codegen.cpp

/*
** codegen.cpp
**
** Compiler backend / code generation for ZScript and DECORATE
**
**---------------------------------------------------------------------------
** Copyright 2008-2016 Christoph Oelckers
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
**    derived from this software without specific prior written permission.
** 4. When not used as part of ZDoom or a ZDoom derivative, this code will be
**    covered by the terms of the GNU General Public License as published by
**    the Free Software Foundation; either version 2 of the License, or (at
**    your option) any later version.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/

#include <stdlib.h>
#include "actor.h"
#include "cmdlib.h"
#include "a_pickups.h"
#include "thingdef.h"
#include "p_lnspec.h"
#include "codegen.h"
#include "v_text.h"
#include "w_wad.h"
#include "doomstat.h"
#include "g_levellocals.h"
#include "v_video.h"
#include "utf8.h"

extern FRandom pr_exrandom;
FMemArena FxAlloc(65536);

struct FLOP
{
	ENamedName Name;
	int Flop;
	double (*Evaluate)(double);
};

// Decorate operates on degrees, so the evaluate functions need to convert
// degrees to radians for those that work with angles.
static const FLOP FxFlops[] =
{
	{ NAME_Exp,		FLOP_EXP,		[](double v) { return g_exp(v); } },
	{ NAME_Log,		FLOP_LOG,		[](double v) { return g_log(v); } },
	{ NAME_Log10,	FLOP_LOG10,		[](double v) { return g_log10(v); } },
	{ NAME_Sqrt,	FLOP_SQRT,		[](double v) { return g_sqrt(v); } },
	{ NAME_Ceil,	FLOP_CEIL,		[](double v) { return ceil(v); } },
	{ NAME_Floor,	FLOP_FLOOR,		[](double v) { return floor(v); } },

	{ NAME_ACos,	FLOP_ACOS_DEG,	[](double v) { return g_acos(v) * (180.0 / M_PI); } },
	{ NAME_ASin,	FLOP_ASIN_DEG,	[](double v) { return g_asin(v) * (180.0 / M_PI); } },
	{ NAME_ATan,	FLOP_ATAN_DEG,	[](double v) { return g_atan(v) * (180.0 / M_PI); } },
	{ NAME_Cos,		FLOP_COS_DEG,	[](double v) { return g_cosdeg(v); } },
	{ NAME_Sin,		FLOP_SIN_DEG,	[](double v) { return g_sindeg(v); } },
	{ NAME_Tan,		FLOP_TAN_DEG,	[](double v) { return g_tan(v * (M_PI / 180.0)); } },

	{ NAME_CosH,	FLOP_COSH,		[](double v) { return g_cosh(v); } },
	{ NAME_SinH,	FLOP_SINH,		[](double v) { return g_sinh(v); } },
	{ NAME_TanH,	FLOP_TANH,		[](double v) { return g_tanh(v); } },

	{ NAME_Round,	FLOP_ROUND,		[](double v) { return round(v);  } },
};


//==========================================================================
//
// FCompileContext
//
//==========================================================================

FCompileContext::FCompileContext(PNamespace *cg, PFunction *fnc, PPrototype *ret, bool fromdecorate, int stateindex, int statecount, int lump, const VersionInfo &ver) 
	: ReturnProto(ret), Function(fnc), Class(nullptr), FromDecorate(fromdecorate), StateIndex(stateindex), StateCount(statecount), Lump(lump), CurGlobals(cg), Version(ver)
{
	if (Version >= MakeVersion(2, 3))
	{
		VersionString.Format("ZScript version %d.%d.%d", Version.major, Version.minor, Version.revision);
	}
	else
	{
		VersionString =  "DECORATE";
	}

	if (fnc != nullptr) Class = fnc->OwningClass;
}

FCompileContext::FCompileContext(PNamespace *cg, PContainerType *cls, bool fromdecorate) 
	: ReturnProto(nullptr), Function(nullptr), Class(cls), FromDecorate(fromdecorate), StateIndex(-1), StateCount(0), Lump(-1), CurGlobals(cg)
{
}

PSymbol *FCompileContext::FindInClass(FName identifier, PSymbolTable *&symt)
{
	return Class != nullptr? Class->Symbols.FindSymbolInTable(identifier, symt) : nullptr;
}

PSymbol *FCompileContext::FindInSelfClass(FName identifier, PSymbolTable *&symt)
{
	// If we have no self we cannot retrieve any values from it.
	if (Function == nullptr || Function->Variants[0].SelfClass == nullptr) return nullptr;
	return Function->Variants[0].SelfClass->Symbols.FindSymbolInTable(identifier, symt);
}
PSymbol *FCompileContext::FindGlobal(FName identifier)
{
	return CurGlobals->Symbols.FindSymbol(identifier, true);
}

void FCompileContext::CheckReturn(PPrototype *proto, FScriptPosition &pos)
{
	assert(proto != nullptr);
	bool fail = false;

	if (ReturnProto == nullptr)
	{
		ReturnProto = proto;
		return;
	}

	// A prototype that defines fewer return types can be compatible with
	// one that defines more if the shorter one matches the initial types
	// for the longer one.
	if (ReturnProto->ReturnTypes.Size() < proto->ReturnTypes.Size())
	{ // Make proto the shorter one to avoid code duplication below.
		swapvalues(proto, ReturnProto);
	}
	// If one prototype returns nothing, they both must.
	if (proto->ReturnTypes.Size() == 0)
	{
		if (ReturnProto->ReturnTypes.Size() != 0)
		{
			fail = true;
		}
	}
	else
	{
		for (unsigned i = 0; i < proto->ReturnTypes.Size(); i++)
		{
			if (ReturnProto->ReturnTypes[i] != proto->ReturnTypes[i])
			{ // Incompatible
				Printf("Return type %s mismatch with %s\n", ReturnProto->ReturnTypes[i]->DescriptiveName(), proto->ReturnTypes[i]->DescriptiveName());
				fail = true;
				break;
			}
		}
	}

	if (fail)
	{
		pos.Message(MSG_ERROR, "Return type mismatch");
	}
}

// [ZZ] I find it really dumb that something called CheckReadOnly returns false for readonly. renamed.
bool FCompileContext::CheckWritable(int flags)
{
	if (!(flags & VARF_ReadOnly)) return false;
	if (!(flags & VARF_InternalAccess)) return true;
	return Wads.GetLumpFile(Lump) != 0;
}

FxLocalVariableDeclaration *FCompileContext::FindLocalVariable(FName name)
{
	if (Block == nullptr)
	{
		return nullptr;
	}
	else
	{
		return Block->FindLocalVariable(name, *this);
	}
}

static PContainerType *FindContainerType(FName name, FCompileContext &ctx)
{
	auto sym = ctx.Class != nullptr? ctx.Class->Symbols.FindSymbol(name, true) : nullptr;
	if (sym == nullptr) sym = ctx.CurGlobals->Symbols.FindSymbol(name, true);
	if (sym && sym->IsKindOf(RUNTIME_CLASS(PSymbolType)))
	{
		auto type = static_cast<PSymbolType*>(sym);
		return type->Type->toContainer();
	}
	return nullptr;
}

// This is for resolving class identifiers which need to be context aware, unlike class names.
static PClass *FindClassType(FName name, FCompileContext &ctx)
{
	auto sym = ctx.CurGlobals->Symbols.FindSymbol(name, true);
	if (sym && sym->IsKindOf(RUNTIME_CLASS(PSymbolType)))
	{
		auto type = static_cast<PSymbolType*>(sym);
		auto ctype = PType::toClass(type->Type);
		if (ctype) return ctype->Descriptor;
	}
	return nullptr;
}

bool isActor(PContainerType *type)
{
	auto cls = PType::toClass(type);
	return cls ? cls->Descriptor->IsDescendantOf(RUNTIME_CLASS(AActor)) : false;
}

//==========================================================================
//
// ExpEmit
//
//==========================================================================

ExpEmit::ExpEmit(VMFunctionBuilder *build, int type, int count)
: RegNum(build->Registers[type].Get(count)), RegType(type), RegCount(count), Konst(false), Fixed(false), Final(false), Target(false)
{
}

void ExpEmit::Free(VMFunctionBuilder *build)
{
	if (!Fixed && !Konst && RegType <= REGT_TYPE)
	{
		build->Registers[RegType].Return(RegNum, RegCount);
	}
}

void ExpEmit::Reuse(VMFunctionBuilder *build)
{
	if (!Fixed && !Konst)
	{
		assert(RegCount == 1);
		bool success = build->Registers[RegType].Reuse(RegNum);
		assert(success && "Attempt to reuse a register that is already in use");
	}
}

//==========================================================================
//
// FindBuiltinFunction
//
// Returns the symbol for a decorate utility function. If not found, create
// it and install it a local symbol table.
//
//==========================================================================

static PFunction *FindBuiltinFunction(FName funcname)
{
	return dyn_cast<PFunction>(RUNTIME_CLASS(DObject)->FindSymbol(funcname, true));
}

//==========================================================================
//
//
//
//==========================================================================

static bool AreCompatiblePointerTypes(PType *dest, PType *source, bool forcompare = false)
{
	if (dest->isPointer() && source->isPointer())
	{
		auto fromtype = source->toPointer();
		auto totype = dest->toPointer();
		// null pointers can be assigned to everything, everything can be assigned to void pointers.
		if (fromtype == nullptr || totype == TypeVoidPtr) return true;
		// when comparing const-ness does not matter.
		if (!forcompare && totype->IsConst != fromtype->IsConst) return false;
		// A type is always compatible to itself.
		if (fromtype == totype) return true;
		// Pointers to different types are only compatible if both point to an object and the source type is a child of the destination type.
		if (source->isObjectPointer() && dest->isObjectPointer())
		{
			auto fromcls = static_cast<PObjectPointer*>(source)->PointedClass();
			auto tocls = static_cast<PObjectPointer*>(dest)->PointedClass();
			if (forcompare && tocls->IsDescendantOf(fromcls)) return true;
			return (fromcls->IsDescendantOf(tocls));
		}
		// The same rules apply to class pointers. A child type can be assigned to a variable of a parent type.
		if (source->isClassPointer() && dest->isClassPointer())
		{
			auto fromcls = static_cast<PClassPointer*>(source)->ClassRestriction;
			auto tocls = static_cast<PClassPointer*>(dest)->ClassRestriction;
			if (forcompare && tocls->IsDescendantOf(fromcls)) return true;
			return (fromcls->IsDescendantOf(tocls));
		}
	}
	return false;
}


//==========================================================================
//
//
//
//==========================================================================

static FxExpression *StringConstToChar(FxExpression *basex)
{
	if (!basex->isConstant()) return nullptr;
	// Allow single character string literals be convertible to integers.
	// This serves as workaround for not being able to use single quoted literals because those are taken for names.
	ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
	FString str = constval.GetString();
	int position = 0;
	int chr = str.GetNextCharacter(position);

	// Only succeed if the full string is consumed, i.e. it contains only one code point.
	if (position == (int)str.Len())
	{
		return new FxConstant(chr, basex->ScriptPosition);
	}
	return nullptr;
}
//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxExpression::Emit (VMFunctionBuilder *build)
{
	ScriptPosition.Message(MSG_ERROR, "Unemitted expression found");
	return ExpEmit();
}


//==========================================================================
//
// Emits a statement and records its position in the source.
//
//==========================================================================

void FxExpression::EmitStatement(VMFunctionBuilder *build)
{
	build->BeginStatement(this);
	ExpEmit exp = Emit(build);
	exp.Free(build);
	build->EndStatement();
}


//==========================================================================
//
//
//
//==========================================================================

void FxExpression::EmitCompare(VMFunctionBuilder *build, bool invert, TArray<size_t> &patchspots_yes, TArray<size_t> &patchspots_no)
{
	ExpEmit op = Emit(build);
	ExpEmit i;
	assert(op.RegType != REGT_NIL && op.RegCount == 1);
	if (op.Konst)
	{
		ScriptPosition.Message(MSG_WARNING, "Conditional expression is constant");
	}
	switch (op.RegType)
	{
	case REGT_INT:
		build->Emit(OP_EQ_K, !invert, op.RegNum, build->GetConstantInt(0));
		break;

	case REGT_FLOAT:
		build->Emit(OP_EQF_K, !invert, op.RegNum, build->GetConstantFloat(0));
		break;

	case REGT_POINTER:
		build->Emit(OP_EQA_K, !invert, op.RegNum, build->GetConstantAddress(0));
		break;

	case REGT_STRING:
		i = ExpEmit(build, REGT_INT);
		build->Emit(OP_LENS, i.RegNum, op.RegNum);
		build->Emit(OP_EQ_K, !invert, i.RegNum, build->GetConstantInt(0));
		i.Free(build);
		break;

	default:
		break;
	}
	patchspots_no.Push(build->Emit(OP_JMP, 0));
	op.Free(build);
}

//==========================================================================
//
//
//
//==========================================================================

bool FxExpression::isConstant() const
{
	return false;
}

//==========================================================================
//
//
//
//==========================================================================

VMFunction *FxExpression::GetDirectFunction(PFunction *callingfunc, const VersionInfo &ver)
{
	return nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxExpression::Resolve(FCompileContext &ctx)
{
	isresolved = true;
	return this;
}

//==========================================================================
//
// Returns true if we can write to the address.
//
//==========================================================================

bool FxExpression::RequestAddress(FCompileContext &ctx, bool *writable)
{
	if (writable != nullptr) *writable = false;
	return false;
}

//==========================================================================
//
// Called by return statements.
//
//==========================================================================

PPrototype *FxExpression::ReturnProto()
{
	assert(ValueType != nullptr);

	TArray<PType *> ret(0);
	TArray<PType *> none(0);
	if (ValueType != TypeVoid)
	{
		ret.Push(ValueType);
	}

	return NewPrototype(ret, none);
}

//==========================================================================
//
//
//
//==========================================================================

int EncodeRegType(ExpEmit reg)
{
	int regtype = reg.RegType;
	if (reg.Fixed && reg.Target)
	{
		regtype |= REGT_ADDROF;
	}
	if (reg.Konst)
	{
		regtype |= REGT_KONST;
	}
	else if (reg.RegCount == 2)
	{
		regtype |= REGT_MULTIREG2;

	}
	else if (reg.RegCount == 3)
	{
		regtype |= REGT_MULTIREG3;
	}
	return regtype;
}


//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxConstant::MakeConstant(PSymbol *sym, const FScriptPosition &pos)
{
	FxExpression *x;
	PSymbolConstNumeric *csym = dyn_cast<PSymbolConstNumeric>(sym);
	if (csym != nullptr)
	{
		if (csym->ValueType->isInt())
		{
			x = new FxConstant(csym->Value, pos);
		}
		else if (csym->ValueType->isFloat())
		{
			x = new FxConstant(csym->Float, pos);
		}
		else
		{
			pos.Message(MSG_ERROR, "Invalid constant '%s'\n", csym->SymbolName.GetChars());
			return nullptr;
		}
	}
	else
	{
		PSymbolConstString *csym = dyn_cast<PSymbolConstString>(sym);
		if (csym != nullptr)
		{
			x = new FxConstant(csym->Str, pos);
		}
		else
		{
			pos.Message(MSG_ERROR, "'%s' is not a constant\n", sym->SymbolName.GetChars());
			x = nullptr;
		}
	}
	return x;
}

ExpEmit FxConstant::Emit(VMFunctionBuilder *build)
{
	ExpEmit out;

	out.Konst = true;
	int regtype = value.Type->GetRegType();
	out.RegType = regtype;
	if (regtype == REGT_INT)
	{
		out.RegNum = build->GetConstantInt(value.Int);
	}
	else if (regtype == REGT_FLOAT)
	{
		out.RegNum = build->GetConstantFloat(value.Float);
	}
	else if (regtype == REGT_POINTER)
	{
		out.RegNum = build->GetConstantAddress(value.pointer);
	}
	else if (regtype == REGT_STRING)
	{
		out.RegNum = build->GetConstantString(value.GetString());
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Cannot emit needed constant");
		out.RegNum = 0;
	}
	return out;
}

//==========================================================================
//
//
//
//==========================================================================

FxVectorValue::FxVectorValue(FxExpression *x, FxExpression *y, FxExpression *z, const FScriptPosition &sc)
	:FxExpression(EFX_VectorValue, sc)
{
	xyz[0] = x;
	xyz[1] = y;
	xyz[2] = z;
	isConst = false;
	ValueType = TypeVoid;	// we do not know yet
}

FxVectorValue::~FxVectorValue()
{
	for (auto &a : xyz)
	{
		SAFE_DELETE(a);
	}
}

FxExpression *FxVectorValue::Resolve(FCompileContext&ctx)
{
	bool fails = false;

	for (auto &a : xyz)
	{
		if (a != nullptr)
		{
			a = a->Resolve(ctx);
			if (a == nullptr) fails = true;
			else
			{
				if (a->ValueType != TypeVector2)	// a vec3 may be initialized with (vec2, z)
				{
					a = new FxFloatCast(a);
					a = a->Resolve(ctx);
					fails |= (a == nullptr);
				}
			}
		}
	}
	if (fails)
	{
		delete this;
		return nullptr;
	}
	// at this point there are three legal cases:
	// * two floats = vector2
	// * three floats = vector3
	// * vector2 + float = vector3
	if (xyz[0]->ValueType == TypeVector2)
	{
		if (xyz[1]->ValueType != TypeFloat64 || xyz[2] != nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Not a valid vector");
			delete this;
			return nullptr;
		}
		ValueType = TypeVector3;
		if (xyz[0]->ExprType == EFX_VectorValue)
		{
			// If two vector initializers are nested, unnest them now.
			auto vi = static_cast<FxVectorValue*>(xyz[0]);
			xyz[2] = xyz[1];
			xyz[1] = vi->xyz[1];
			xyz[0] = vi->xyz[0];
			vi->xyz[0] = vi->xyz[1] = nullptr; // Don't delete our own expressions.
			delete vi;
		}
	}
	else if (xyz[0]->ValueType == TypeFloat64 && xyz[1]->ValueType == TypeFloat64)
	{
		ValueType = xyz[2] == nullptr ? TypeVector2 : TypeVector3;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Not a valid vector");
		delete this;
		return nullptr;
	}

	// check if all elements are constant. If so this can be emitted as a constant vector.
	isConst = true;
	for (auto &a : xyz)
	{
		if (a != nullptr && !a->isConstant()) isConst = false;
	}
	return this;
}

static ExpEmit EmitKonst(VMFunctionBuilder *build, ExpEmit &emit)
{
	if (emit.Konst)
	{
		ExpEmit out(build, REGT_FLOAT);
		build->Emit(OP_LKF, out.RegNum, emit.RegNum);
		return out;
	}
	return emit;
}

ExpEmit FxVectorValue::Emit(VMFunctionBuilder *build)
{
	// no const handling here. Ultimately it's too rarely used (i.e. the only fully constant vector ever allocated in ZDoom is the 0-vector in a very few places)
	// and the negatives (excessive allocation of float constants) outweigh the positives (saved a few instructions)
	assert(xyz[0] != nullptr);
	assert(xyz[1] != nullptr);
	if (ValueType == TypeVector2)
	{
		ExpEmit tempxval = xyz[0]->Emit(build);
		ExpEmit tempyval = xyz[1]->Emit(build);
		ExpEmit xval = EmitKonst(build, tempxval);
		ExpEmit yval = EmitKonst(build, tempyval);
		assert(xval.RegType == REGT_FLOAT && yval.RegType == REGT_FLOAT);
		if (yval.RegNum == xval.RegNum + 1)
		{
			// The results are already in two continuous registers so just return them as-is.
			xval.RegCount++;
			return xval;
		}
		else
		{
			// The values are not in continuous registers so they need to be copied together now.
			ExpEmit out(build, REGT_FLOAT, 2);
			build->Emit(OP_MOVEF, out.RegNum, xval.RegNum);
			build->Emit(OP_MOVEF, out.RegNum + 1, yval.RegNum);
			xval.Free(build);
			yval.Free(build);
			return out;
		}
	}
	else if (xyz[0]->ValueType == TypeVector2)	// vec2+float
	{
		ExpEmit xyval = xyz[0]->Emit(build);
		ExpEmit tempzval = xyz[1]->Emit(build);
		ExpEmit zval = EmitKonst(build, tempzval);
		assert(xyval.RegType == REGT_FLOAT && xyval.RegCount == 2 && zval.RegType == REGT_FLOAT);
		if (zval.RegNum == xyval.RegNum + 2)
		{
			// The results are already in three continuous registers so just return them as-is.
			xyval.RegCount++;
			return xyval;
		}
		else
		{
			// The values are not in continuous registers so they need to be copied together now.
			ExpEmit out(build, REGT_FLOAT, 3);
			build->Emit(OP_MOVEV2, out.RegNum, xyval.RegNum);
			build->Emit(OP_MOVEF, out.RegNum + 2, zval.RegNum);
			xyval.Free(build);
			zval.Free(build);
			return out;
		}
	}
	else // 3*float
	{
		assert(xyz[2] != nullptr);
		ExpEmit tempxval = xyz[0]->Emit(build);
		ExpEmit tempyval = xyz[1]->Emit(build);
		ExpEmit tempzval = xyz[2]->Emit(build);
		ExpEmit xval = EmitKonst(build, tempxval);
		ExpEmit yval = EmitKonst(build, tempyval);
		ExpEmit zval = EmitKonst(build, tempzval);
		assert(xval.RegType == REGT_FLOAT && yval.RegType == REGT_FLOAT && zval.RegType == REGT_FLOAT);
		if (yval.RegNum == xval.RegNum + 1 && zval.RegNum == xval.RegNum + 2)
		{
			// The results are already in three continuous registers so just return them as-is.
			xval.RegCount += 2;
			return xval;
		}
		else
		{
			// The values are not in continuous registers so they need to be copied together now.
			ExpEmit out(build, REGT_FLOAT, 3);
			//Try to optimize a bit...
			if (yval.RegNum == xval.RegNum + 1)
			{
				build->Emit(OP_MOVEV2, out.RegNum, xval.RegNum);
				build->Emit(OP_MOVEF, out.RegNum + 2, zval.RegNum);
			}
			else if (zval.RegNum == yval.RegNum + 1)
			{
				build->Emit(OP_MOVEF, out.RegNum, xval.RegNum);
				build->Emit(OP_MOVEV2, out.RegNum+1, yval.RegNum);
			}
			else
			{
				build->Emit(OP_MOVEF, out.RegNum, xval.RegNum);
				build->Emit(OP_MOVEF, out.RegNum + 1, yval.RegNum);
				build->Emit(OP_MOVEF, out.RegNum + 2, zval.RegNum);
			}
			xval.Free(build);
			yval.Free(build);
			zval.Free(build);
			return out;
		}
	}
}

//==========================================================================
//
//
//
//==========================================================================

FxBoolCast::FxBoolCast(FxExpression *x, bool needvalue)
	: FxExpression(EFX_BoolCast, x->ScriptPosition)
{
	basex = x;
	ValueType = TypeBool;
	NeedValue = needvalue;
}

//==========================================================================
//
//
//
//==========================================================================

FxBoolCast::~FxBoolCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxBoolCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (basex->ValueType == TypeBool)
	{
		FxExpression *x = basex;
		basex = nullptr;
		delete this;
		return x;
	}
	else if (basex->IsBoolCompat())
	{
		if (basex->isConstant())
		{
			assert(basex->ValueType != TypeState && "We shouldn't be able to generate a constant state ref");

			ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
			FxExpression *x = new FxConstant(constval.GetBool(), ScriptPosition);
			delete this;
			return x;
		}
		return this;
	}
	ScriptPosition.Message(MSG_ERROR, "Numeric type expected");
	delete this;
	return nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxBoolCast::Emit(VMFunctionBuilder *build)
{
	ExpEmit from = basex->Emit(build);
	assert(!from.Konst);
	assert(basex->ValueType->GetRegType() == REGT_INT || basex->ValueType->GetRegType() == REGT_FLOAT || basex->ValueType->GetRegType() == REGT_POINTER);

	if (NeedValue)
	{
		ExpEmit to(build, REGT_INT);
		from.Free(build);
		build->Emit(OP_CASTB, to.RegNum, from.RegNum, from.RegType == REGT_INT ? CASTB_I : from.RegType == REGT_FLOAT ? CASTB_F : CASTB_A);
		return to;
	}
	else
	{
		return from;
	}
}

//==========================================================================
//
//
//
//==========================================================================

void FxBoolCast::EmitCompare(VMFunctionBuilder *build, bool invert, TArray<size_t> &patchspots_yes, TArray<size_t> &patchspots_no)
{
	basex->EmitCompare(build, invert, patchspots_yes, patchspots_no);
}

//==========================================================================
//
//
//
//==========================================================================

FxIntCast::FxIntCast(FxExpression *x, bool nowarn, bool explicitly, bool isunsigned)
: FxExpression(EFX_IntCast, x->ScriptPosition)
{
	basex=x;
	ValueType = isunsigned ? TypeUInt32 : TypeSInt32;
	NoWarn = nowarn;
	Explicit = explicitly;
}

//==========================================================================
//
//
//
//==========================================================================

FxIntCast::~FxIntCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxIntCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (basex->ValueType->GetRegType() == REGT_INT)
	{
		if (basex->ValueType->isNumeric() || Explicit)	// names can be converted to int, but only with an explicit type cast.
		{
			FxExpression *x = basex;
			x->ValueType = ValueType;
			basex = nullptr;
			delete this;
			return x;
		}
		else
		{
			// Ugh. This should abort, but too many mods fell into this logic hole somewhere, so this serious error needs to be reduced to a warning. :(
			// At least in ZScript, MSG_OPTERROR always means to report an error, not a warning so the problem only exists in DECORATE.
			if (!basex->isConstant())	
				ScriptPosition.Message(MSG_OPTERROR, "Numeric type expected, got a name");
			else ScriptPosition.Message(MSG_OPTERROR, "Numeric type expected, got \"%s\"", static_cast<FxConstant*>(basex)->GetValue().GetName().GetChars());
			FxExpression * x = new FxConstant(0, ScriptPosition);
			delete this;
			return x;
		}
	}
	else if (basex->IsFloat())
	{
		if (basex->isConstant())
		{
			ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
			FxExpression *x = new FxConstant(constval.GetInt(), ScriptPosition);
			if (constval.GetInt() != constval.GetFloat())
			{
				ScriptPosition.Message(MSG_WARNING, "Truncation of floating point constant %f", constval.GetFloat());
			}

			delete this;
			return x;
		}
		else if (!NoWarn)
		{
			ScriptPosition.Message(MSG_DEBUGWARN, "Truncation of floating point value");
		}

		return this;
	}
	else if (basex->ValueType == TypeString && basex->isConstant())
	{
		FxExpression *x = StringConstToChar(basex);
		if (x)
		{
			x->ValueType = ValueType;
			basex = nullptr;
			delete this;
			return x;
		}
	}
	ScriptPosition.Message(MSG_ERROR, "Numeric type expected");
	delete this;
	return nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxIntCast::Emit(VMFunctionBuilder *build)
{
	ExpEmit from = basex->Emit(build);
	assert(!from.Konst);
	assert(basex->ValueType->GetRegType() == REGT_FLOAT);
	from.Free(build);
	ExpEmit to(build, REGT_INT);
	build->Emit(OP_CAST, to.RegNum, from.RegNum, ValueType == TypeUInt32? CAST_F2U : CAST_F2I);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxFloatCast::FxFloatCast(FxExpression *x)
	: FxExpression(EFX_FloatCast, x->ScriptPosition)
{
	basex = x;
	ValueType = TypeFloat64;
}

//==========================================================================
//
//
//
//==========================================================================

FxFloatCast::~FxFloatCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxFloatCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (basex->IsFloat())
	{
		FxExpression *x = basex;
		x->ValueType = ValueType;
		basex = nullptr;
		delete this;
		return x;
	}
	else if (basex->ValueType->GetRegType() == REGT_INT)
	{
		if (basex->ValueType->isNumeric())
		{
			if (basex->isConstant())
			{
				ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
				FxExpression *x = new FxConstant(constval.GetFloat(), ScriptPosition);
				delete this;
				return x;
			}
			return this;
		}
		else
		{
			// Ugh. This should abort, but too many mods fell into this logic hole somewhere, so this seroious error needs to be reduced to a warning. :(
			// At least in ZScript, MSG_OPTERROR always means to report an error, not a warning so the problem only exists in DECORATE.
			if (!basex->isConstant()) ScriptPosition.Message(MSG_OPTERROR, "Numeric type expected, got a name");
			else ScriptPosition.Message(MSG_OPTERROR, "Numeric type expected, got \"%s\"", static_cast<FxConstant*>(basex)->GetValue().GetName().GetChars());
			FxExpression *x = new FxConstant(0.0, ScriptPosition);
			delete this;
			return x;
		}
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Numeric type expected");
		delete this;
		return nullptr;
	}
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxFloatCast::Emit(VMFunctionBuilder *build)
{
	ExpEmit from = basex->Emit(build);
	assert(!from.Konst);
	assert(basex->ValueType->GetRegType() == REGT_INT);
	from.Free(build);
	ExpEmit to(build, REGT_FLOAT);
	build->Emit(OP_CAST, to.RegNum, from.RegNum, basex->ValueType == TypeUInt32? CAST_U2F : CAST_I2F);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxNameCast::FxNameCast(FxExpression *x, bool explicitly)
	: FxExpression(EFX_NameCast, x->ScriptPosition)
{
	basex = x;
	ValueType = TypeName;
	mExplicit = explicitly;
}

//==========================================================================
//
//
//
//==========================================================================

FxNameCast::~FxNameCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxNameCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (mExplicit && basex->ValueType->isClassPointer())
	{
		if (basex->isConstant())
		{
			auto constval = static_cast<FxConstant *>(basex)->GetValue().GetPointer();
			FxExpression *x = new FxConstant(static_cast<PClass*>(constval)->TypeName, ScriptPosition);
			delete this;
			return x;
		}
		return this;
	}
	else if (basex->ValueType == TypeName)
	{
		FxExpression *x = basex;
		basex = nullptr;
		delete this;
		return x;
	}
	else if (basex->ValueType == TypeString)
	{
		if (basex->isConstant())
		{
			ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
			FxExpression *x = new FxConstant(constval.GetName(), ScriptPosition);
			delete this;
			return x;
		}
		return this;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Cannot convert to name");
		delete this;
		return nullptr;
	}
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxNameCast::Emit(VMFunctionBuilder *build)
{
	if (basex->ValueType == TypeString)
	{
		ExpEmit from = basex->Emit(build);
		assert(!from.Konst);
		assert(basex->ValueType == TypeString);
		from.Free(build);
		ExpEmit to(build, REGT_INT);
		build->Emit(OP_CAST, to.RegNum, from.RegNum, CAST_S2N);
		return to;
	}
	else
	{
		ExpEmit ptr = basex->Emit(build);
		assert(ptr.RegType == REGT_POINTER);
		ptr.Free(build);
		ExpEmit to(build, REGT_INT);
		build->Emit(OP_LW, to.RegNum, ptr.RegNum, build->GetConstantInt(myoffsetof(PClassActor, TypeName)));
		return to;
	}
}

//==========================================================================
//
//
//
//==========================================================================

FxStringCast::FxStringCast(FxExpression *x)
	: FxExpression(EFX_StringCast, x->ScriptPosition)
{
	basex = x;
	ValueType = TypeString;
}

//==========================================================================
//
//
//
//==========================================================================

FxStringCast::~FxStringCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxStringCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (basex->ValueType == TypeString)
	{
		FxExpression *x = basex;
		basex = nullptr;
		delete this;
		return x;
	}
	else if (basex->ValueType == TypeName)
	{
		if (basex->isConstant())
		{
			ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
			FxExpression *x = new FxConstant(constval.GetString(), ScriptPosition);
			delete this;
			return x;
		}
		return this;
	}
	else if (basex->ValueType == TypeSound)
	{
		if (basex->isConstant())
		{
			ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
			FxExpression *x = new FxConstant(S_sfx[constval.GetInt()].name, ScriptPosition);
			delete this;
			return x;
		}
		return this;
	}
	// although it could be done, let's not convert colors back to strings.
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Cannot convert to string");
		delete this;
		return nullptr;
	}
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxStringCast::Emit(VMFunctionBuilder *build)
{
	ExpEmit from = basex->Emit(build);
	assert(!from.Konst);

	from.Free(build);
	ExpEmit to(build, REGT_STRING);
	if (basex->ValueType == TypeName)
	{
		build->Emit(OP_CAST, to.RegNum, from.RegNum, CAST_N2S);
	}
	else if (basex->ValueType == TypeSound)
	{
		build->Emit(OP_CAST, to.RegNum, from.RegNum, CAST_So2S);
	}
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxColorCast::FxColorCast(FxExpression *x)
	: FxExpression(EFX_ColorCast, x->ScriptPosition)
{
	basex = x;
	ValueType = TypeColor;
}

//==========================================================================
//
//
//
//==========================================================================

FxColorCast::~FxColorCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxColorCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (basex->ValueType == TypeColor || basex->ValueType->isInt())
	{
		FxExpression *x = basex;
		x->ValueType = TypeColor;
		basex = nullptr;
		delete this;
		return x;
	}
	else if (basex->ValueType == TypeString)
	{
		if (basex->isConstant())
		{
			ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
			if (constval.GetString().Len() == 0)
			{
				// empty string means 'no state'. This would otherwise just cause endless errors and have the same result anyway.
				FxExpression *x = new FxConstant(-1, ScriptPosition);
				delete this;
				return x;
			}
			else
			{
				FxExpression *x = new FxConstant(V_GetColor(nullptr, constval.GetString(), &ScriptPosition), ScriptPosition);
				delete this;
				return x;
			}
		}
		return this;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Cannot convert to color");
		delete this;
		return nullptr;
	}
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxColorCast::Emit(VMFunctionBuilder *build)
{
	ExpEmit from = basex->Emit(build);
	assert(!from.Konst);
	assert(basex->ValueType == TypeString);
	from.Free(build);
	ExpEmit to(build, REGT_INT);
	build->Emit(OP_CAST, to.RegNum, from.RegNum, CAST_S2Co);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxSoundCast::FxSoundCast(FxExpression *x)
	: FxExpression(EFX_SoundCast, x->ScriptPosition)
{
	basex = x;
	ValueType = TypeSound;
}

//==========================================================================
//
//
//
//==========================================================================

FxSoundCast::~FxSoundCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxSoundCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (basex->ValueType == TypeSound || basex->ValueType->isInt())
	{
		FxExpression *x = basex;
		x->ValueType = TypeSound;
		basex = nullptr;
		delete this;
		return x;
	}
	else if (basex->ValueType == TypeString)
	{
		if (basex->isConstant())
		{
			ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
			FxExpression *x = new FxConstant(FSoundID(constval.GetString()), ScriptPosition);
			delete this;
			return x;
		}
		return this;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Cannot convert to sound");
		delete this;
		return nullptr;
	}
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxSoundCast::Emit(VMFunctionBuilder *build)
{
	ExpEmit from = basex->Emit(build);
	assert(!from.Konst);
	assert(basex->ValueType == TypeString);
	from.Free(build);
	ExpEmit to(build, REGT_INT);
	build->Emit(OP_CAST, to.RegNum, from.RegNum, CAST_S2So);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxFontCast::FxFontCast(FxExpression *x)
	: FxExpression(EFX_FontCast, x->ScriptPosition)
{
	basex = x;
	ValueType = TypeSound;
}

//==========================================================================
//
//
//
//==========================================================================

FxFontCast::~FxFontCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxFontCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (basex->ValueType == TypeFont)
	{
		FxExpression *x = basex;
		basex = nullptr;
		delete this;
		return x;
	}
	// This intentionally does not convert non-constants.
	// The sole reason for this cast is to allow passing both font pointers and string constants to printing functions and have the font names checked at compile time.
	else if ((basex->ValueType == TypeString || basex->ValueType == TypeName) && basex->isConstant())
	{
		ExpVal constval = static_cast<FxConstant *>(basex)->GetValue();
		FFont *font = V_GetFont(constval.GetString());
		// Font must exist. Most internal functions working with fonts do not like null pointers.
		// If checking is needed scripts will have to call Font.GetFont themselves.
		if (font == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Unknown font '%s'", constval.GetString().GetChars());
			delete this;
			return nullptr;
		}

		FxExpression *x = new FxConstant(font, ScriptPosition);
		delete this;
		return x;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Cannot convert to font");
		delete this;
		return nullptr;
	}
}


//==========================================================================
//
// generic type cast operator
//
//==========================================================================

FxTypeCast::FxTypeCast(FxExpression *x, PType *type, bool nowarn, bool explicitly)
	: FxExpression(EFX_TypeCast, x->ScriptPosition)
{
	basex = x;
	ValueType = type;
	NoWarn = nowarn;
	Explicit = explicitly;
	assert(ValueType != nullptr);
}

//==========================================================================
//
//
//
//==========================================================================

FxTypeCast::~FxTypeCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxTypeCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	// first deal with the simple types
	if (ValueType == TypeError || basex->ValueType == TypeError || basex->ValueType == nullptr)
	{
		ScriptPosition.Message(MSG_ERROR, "Trying to cast to invalid type.");
		delete this;
		return nullptr;
	}
	else if (ValueType == TypeVoid)	// this should never happen
	{
		goto errormsg;
	}
	else if (basex->ValueType == TypeVoid)
	{
		goto errormsg;
	}
	else if (basex->ValueType == ValueType)
	{
		// don't go through the entire list if the types are the same.
		goto basereturn;
	}
	else if (basex->ValueType == TypeNullPtr && ValueType->isPointer())
	{
		goto basereturn;
	}
	else if (IsFloat())
	{
		FxExpression *x = new FxFloatCast(basex);
		x = x->Resolve(ctx);
		basex = nullptr;
		delete this;
		return x;
	}
	else if (ValueType->isInt())
	{
		// This is only for casting to actual ints. Subtypes representing an int will be handled elsewhere.
		FxExpression *x = new FxIntCast(basex, NoWarn, Explicit, static_cast<PInt*>(ValueType)->Unsigned);
		x = x->Resolve(ctx);
		basex = nullptr;
		delete this;
		return x;
	}
	else if (ValueType == TypeBool)
	{
		FxExpression *x = new FxBoolCast(basex);
		x = x->Resolve(ctx);
		basex = nullptr;
		delete this;
		return x;
	}
	else if (ValueType == TypeString)
	{
		FxExpression *x = new FxStringCast(basex);
		x = x->Resolve(ctx);
		basex = nullptr;
		delete this;
		return x;
	}
	else if (ValueType == TypeName)
	{
		FxExpression *x = new FxNameCast(basex, Explicit);
		x = x->Resolve(ctx);
		basex = nullptr;
		delete this;
		return x;
	}
	else if (ValueType == TypeSound)
	{
		FxExpression *x = new FxSoundCast(basex);
		x = x->Resolve(ctx);
		basex = nullptr;
		delete this;
		return x;
	}
	else if (ValueType == TypeColor)
	{
		FxExpression *x = new FxColorCast(basex);
		x = x->Resolve(ctx);
		basex = nullptr;
		delete this;
		return x;
	}
	else if (ValueType == TypeSpriteID && basex->IsInteger())
	{
		basex->ValueType = TypeSpriteID;
		auto x = basex;
		basex = nullptr;
		delete this;
		return x;
	}
	else if (ValueType == TypeStateLabel)
	{
		if (basex->ValueType == TypeNullPtr)
		{
			auto x = new FxConstant(0, ScriptPosition);
			x->ValueType = TypeStateLabel;
			delete this;
			return x;
		}
		// Right now this only supports string constants. There should be an option to pass a string variable, too.
		if (basex->isConstant() && (basex->ValueType == TypeString || basex->ValueType == TypeName))
		{
			FString s= static_cast<FxConstant *>(basex)->GetValue().GetString();
			if (s.Len() == 0 && !ctx.FromDecorate)	// DECORATE should never get here at all, but let's better be safe.
			{
				ScriptPosition.Message(MSG_ERROR, "State jump to empty label.");
				delete this;
				return nullptr;
			}
			FxExpression *x = new FxMultiNameState(s, basex->ScriptPosition);
			x = x->Resolve(ctx);
			basex = nullptr;
			delete this;
			return x;
		}
		else if (basex->IsNumeric() && basex->ValueType != TypeSound && basex->ValueType != TypeColor)
		{
			if (ctx.StateIndex < 0)
			{
				ScriptPosition.Message(MSG_ERROR, "State jumps with index can only be used in anonymous state functions.");
				delete this;
				return nullptr;
			}
			if (ctx.StateCount != 1)
			{
				ScriptPosition.Message(MSG_ERROR, "State jumps with index cannot be used on multistate definitions");
				delete this;
				return nullptr;
			}
			if (basex->isConstant())
			{
				int i = static_cast<FxConstant *>(basex)->GetValue().GetInt();
				if (i <= 0)
				{
					ScriptPosition.Message(MSG_ERROR, "State index must be positive");
					delete this;
					return nullptr;
				}
				FxExpression *x = new FxStateByIndex(ctx.StateIndex + i, ScriptPosition);
				x = x->Resolve(ctx);
				basex = nullptr;
				delete this;
				return x;
			}
			else
			{
				FxExpression *x = new FxRuntimeStateIndex(basex);
				x = x->Resolve(ctx);
				basex = nullptr;
				delete this;
				return x;
			}
		}
	}
	else if (ValueType->isClassPointer())
	{
		FxExpression *x = new FxClassTypeCast(static_cast<PClassPointer*>(ValueType), basex, Explicit);
		x = x->Resolve(ctx);
		basex = nullptr;
		delete this;
		return x;
	}
	/* else if (ValueType->isEnum())
	{
	// this is not yet ready and does not get assigned to actual values.
	}
	*/
	else if (ValueType->isClass())	// this should never happen because the VM doesn't handle plain class types - just pointers
	{
		if (basex->ValueType->isClass())
		{
			// class types are only compatible if the base type is a descendant of the result type.
			auto fromtype = static_cast<PClassType *>(basex->ValueType)->Descriptor;
			auto totype = static_cast<PClassType *>(ValueType)->Descriptor;
			if (fromtype->IsDescendantOf(totype)) goto basereturn;
		}
	}
	else if (basex->IsNativeStruct() && ValueType->isRealPointer() && ValueType->toPointer()->PointedType == basex->ValueType)
	{
		bool writable;
		basex->RequestAddress(ctx, &writable);
		basex->ValueType = ValueType;
		auto x = basex;
		basex = nullptr;
		delete this;
		return x;
	}

	else if (AreCompatiblePointerTypes(ValueType, basex->ValueType))
	{
		goto basereturn;
	}
	else if (ValueType == TypeFont)
	{
		FxExpression *x = new FxFontCast(basex);
		x = x->Resolve(ctx);
		basex = nullptr;
		delete this;
		return x;
	}
	// todo: pointers to class objects. 
	// All other types are only compatible to themselves and have already been handled above by the equality check.
	// Anything that falls through here is not compatible and must print an error.

errormsg:
	ScriptPosition.Message(MSG_ERROR, "Cannot convert %s to %s", basex->ValueType->DescriptiveName(), ValueType->DescriptiveName());
	delete this;
	return nullptr;

basereturn:
	auto x = basex;
	x->ValueType = ValueType;
	basex = nullptr;
	delete this;
	return x;

}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxTypeCast::Emit(VMFunctionBuilder *build)
{
	assert(false);
	// This should never be reached
	return ExpEmit();
}

//==========================================================================
//
//
//
//==========================================================================

FxPlusSign::FxPlusSign(FxExpression *operand)
: FxExpression(EFX_PlusSign, operand->ScriptPosition)
{
	Operand=operand;
}

//==========================================================================
//
//
//
//==========================================================================

FxPlusSign::~FxPlusSign()
{
	SAFE_DELETE(Operand);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxPlusSign::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Operand, ctx);

	if (Operand->IsNumeric() || Operand->IsVector())
	{
		FxExpression *e = Operand;
		Operand = nullptr;
		delete this;
		return e;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Numeric type expected");
		delete this;
		return nullptr;
	}
}

ExpEmit FxPlusSign::Emit(VMFunctionBuilder *build)
{
	return Operand->Emit(build);
}

//==========================================================================
//
//
//
//==========================================================================

FxMinusSign::FxMinusSign(FxExpression *operand)
: FxExpression(EFX_MinusSign, operand->ScriptPosition)
{
	Operand=operand;
}

//==========================================================================
//
//
//
//==========================================================================

FxMinusSign::~FxMinusSign()
{
	SAFE_DELETE(Operand);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxMinusSign::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Operand, ctx);

	if (Operand->IsNumeric() || Operand->IsVector())
	{
		if (Operand->isConstant())
		{
			ExpVal val = static_cast<FxConstant *>(Operand)->GetValue();
			FxExpression *e = val.Type->GetRegType() == REGT_INT ?
				new FxConstant(-val.Int, ScriptPosition) :
				new FxConstant(-val.Float, ScriptPosition);
			delete this;
			return e;
		}
		else if (Operand->ValueType == TypeBool)
		{
			Operand = new FxIntCast(Operand, true);
			Operand = Operand->Resolve(ctx);
			assert(Operand != nullptr);
		}
		ValueType = Operand->ValueType;
		return this;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Numeric type expected");
		delete this;
		return nullptr;
	}
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxMinusSign::Emit(VMFunctionBuilder *build)
{
	assert(ValueType == Operand->ValueType);
	ExpEmit from = Operand->Emit(build);
	ExpEmit to;
	assert(from.Konst == 0);
	assert(ValueType->GetRegCount() == from.RegCount);
	// Do it in-place, unless a local variable
	if (from.Fixed)
	{
		to = ExpEmit(build, from.RegType, from.RegCount);
		from.Free(build);
	}
	else
	{
		to = from;
	}

	if (ValueType->GetRegType() == REGT_INT)
	{
		build->Emit(OP_NEG, to.RegNum, from.RegNum, 0);
	}
	else
	{
		assert(ValueType->GetRegType() == REGT_FLOAT);
		switch (from.RegCount)
		{
		case 1:
			build->Emit(OP_FLOP, to.RegNum, from.RegNum, FLOP_NEG);
			break;

		case 2:
			build->Emit(OP_NEGV2, to.RegNum, from.RegNum);
			break;

		case 3:
			build->Emit(OP_NEGV3, to.RegNum, from.RegNum);
			break;

		}
	}
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxUnaryNotBitwise::FxUnaryNotBitwise(FxExpression *operand)
: FxExpression(EFX_UnaryNotBitwise, operand->ScriptPosition)
{
	Operand=operand;
}

//==========================================================================
//
//
//
//==========================================================================

FxUnaryNotBitwise::~FxUnaryNotBitwise()
{
	SAFE_DELETE(Operand);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxUnaryNotBitwise::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Operand, ctx);

	if  (ctx.FromDecorate && Operand->IsFloat() /* lax */)
	{
		// DECORATE allows floats here so cast them to int.
		Operand = new FxIntCast(Operand, true);
		Operand = Operand->Resolve(ctx);
		if (Operand == nullptr) 
		{
			delete this;
			return nullptr;
		}
	}

	// Names were not blocked in DECORATE here after the scripting branch merge. Now they are again.
	if (!Operand->IsInteger())
	{
		ScriptPosition.Message(MSG_ERROR, "Integer type expected");
		delete this;
		return nullptr;
	}

	if (Operand->isConstant())
	{
		int result = ~static_cast<FxConstant *>(Operand)->GetValue().GetInt();
		FxExpression *e = new FxConstant(result, ScriptPosition);
		e->ValueType = Operand->ValueType == TypeUInt32 ? TypeUInt32 : TypeSInt32;
		delete this;
		return e;
	}
	ValueType = Operand->ValueType == TypeUInt32? TypeUInt32 : TypeSInt32;
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxUnaryNotBitwise::Emit(VMFunctionBuilder *build)
{
	assert(Operand->ValueType->GetRegType() == REGT_INT);
	ExpEmit from = Operand->Emit(build);
	from.Free(build);
	ExpEmit to(build, REGT_INT);
	assert(!from.Konst);
	
	build->Emit(OP_NOT, to.RegNum, from.RegNum, 0);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxUnaryNotBoolean::FxUnaryNotBoolean(FxExpression *operand)
: FxExpression(EFX_UnaryNotBoolean, operand->ScriptPosition)
{
	Operand=operand;
}

//==========================================================================
//
//
//
//==========================================================================

FxUnaryNotBoolean::~FxUnaryNotBoolean()
{
	SAFE_DELETE(Operand);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxUnaryNotBoolean::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Operand, ctx);

	if (Operand->ValueType != TypeBool)
	{
		Operand = new FxBoolCast(Operand);
		SAFE_RESOLVE(Operand, ctx);
	}

	if (Operand->isConstant())
	{
		bool result = !static_cast<FxConstant *>(Operand)->GetValue().GetBool();
		FxExpression *e = new FxConstant(result, ScriptPosition);
		delete this;
		return e;
	}

	ValueType = TypeBool;
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxUnaryNotBoolean::Emit(VMFunctionBuilder *build)
{
	assert(Operand->ValueType == TypeBool);
	assert(ValueType == TypeBool || IsInteger());	// this may have been changed by an int cast.
	ExpEmit from = Operand->Emit(build);
	from.Free(build);
	ExpEmit to(build, REGT_INT);
	assert(!from.Konst);
	// boolean not is the same as XOR-ing the lowest bit

	build->Emit(OP_XOR_RK, to.RegNum, from.RegNum, build->GetConstantInt(1));
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

void FxUnaryNotBoolean::EmitCompare(VMFunctionBuilder *build, bool invert, TArray<size_t> &patchspots_yes, TArray<size_t> &patchspots_no)
{
	Operand->EmitCompare(build, !invert, patchspots_yes, patchspots_no);
}

//==========================================================================
//
//
//
//==========================================================================

FxSizeAlign::FxSizeAlign(FxExpression *operand, int which)
	: FxExpression(EFX_SizeAlign, operand->ScriptPosition)
{
	Operand = operand;
	Which = which;
}

//==========================================================================
//
//
//
//==========================================================================

FxSizeAlign::~FxSizeAlign()
{
	SAFE_DELETE(Operand);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxSizeAlign::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Operand, ctx);

	auto type = Operand->ValueType;
	if (Operand->isConstant())
	{
		ScriptPosition.Message(MSG_ERROR, "cannot determine %s of a constant", Which == TK_AlignOf? "alignment" : "size");
		delete this;
		return nullptr;
	}
	else if (!Operand->RequestAddress(ctx, nullptr))
	{
		ScriptPosition.Message(MSG_ERROR, "Operand must be addressable to determine %s", Which == TK_AlignOf ? "alignment" : "size");
		delete this;
		return nullptr;
	}
	else
	{
		FxExpression *x = new FxConstant(Which == TK_AlignOf ? int(type->Align) : int(type->Size), Operand->ScriptPosition);
		delete this;
		return x->Resolve(ctx);
	}
}

ExpEmit FxSizeAlign::Emit(VMFunctionBuilder *build)
{
	return ExpEmit();
}

//==========================================================================
//
// FxPreIncrDecr
//
//==========================================================================

FxPreIncrDecr::FxPreIncrDecr(FxExpression *base, int token)
: FxExpression(EFX_PreIncrDecr, base->ScriptPosition), Token(token), Base(base)
{
	AddressRequested = false;
	AddressWritable = false;
}

FxPreIncrDecr::~FxPreIncrDecr()
{
	SAFE_DELETE(Base);
}

bool FxPreIncrDecr::RequestAddress(FCompileContext &ctx, bool *writable)
{
	AddressRequested = true;
	if (writable != nullptr) *writable = AddressWritable;
	return true;
}

FxExpression *FxPreIncrDecr::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Base, ctx);

	ValueType = Base->ValueType;

	if (!Base->IsNumeric())
	{
		ScriptPosition.Message(MSG_ERROR, "Numeric type expected");
		delete this;
		return nullptr;
	}
	else if (Base->ValueType == TypeBool)
	{
		ScriptPosition.Message(MSG_ERROR, "%s is not allowed on type bool", FScanner::TokenName(Token).GetChars());
		delete this;
		return nullptr;
	}
	if (!Base->RequestAddress(ctx, &AddressWritable) || !AddressWritable )
	{
		ScriptPosition.Message(MSG_ERROR, "Expression must be a modifiable value");
		delete this;
		return nullptr;
	}

	return this;
}

ExpEmit FxPreIncrDecr::Emit(VMFunctionBuilder *build)
{
	assert(Token == TK_Incr || Token == TK_Decr);
	assert(ValueType == Base->ValueType && IsNumeric());

	int zero = build->GetConstantInt(0);
	int regtype = ValueType->GetRegType();
	ExpEmit pointer = Base->Emit(build);
	ExpEmit value = pointer;

	if (!pointer.Target)
	{
		value = ExpEmit(build, regtype);
		build->Emit(ValueType->GetLoadOp(), value.RegNum, pointer.RegNum, zero);
	}

	if (regtype == REGT_INT)
	{
		build->Emit(OP_ADDI, value.RegNum, value.RegNum, uint8_t((Token == TK_Incr) ? 1 : -1));
	}
	else
	{
		build->Emit((Token == TK_Incr) ? OP_ADDF_RK : OP_SUBF_RK, value.RegNum, value.RegNum, build->GetConstantFloat(1.));
	}

	if (!pointer.Target)
	{
		build->Emit(ValueType->GetStoreOp(), pointer.RegNum, value.RegNum, zero);
	}

	if (AddressRequested)
	{
		value.Free(build);
		return pointer;
	}

	pointer.Free(build);
	value.Target = false;	// This is for 'unrequesting' the address of a register variable. If not done here, passing a preincrement expression to a function will generate bad code.
	return value;
}

//==========================================================================
//
// FxPostIncrDecr
//
//==========================================================================

FxPostIncrDecr::FxPostIncrDecr(FxExpression *base, int token)
: FxExpression(EFX_PostIncrDecr, base->ScriptPosition), Token(token), Base(base)
{
}

FxPostIncrDecr::~FxPostIncrDecr()
{
	SAFE_DELETE(Base);
}

FxExpression *FxPostIncrDecr::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Base, ctx);
	bool AddressWritable;

	ValueType = Base->ValueType;

	if (!Base->IsNumeric())
	{
		ScriptPosition.Message(MSG_ERROR, "Numeric type expected");
		delete this;
		return nullptr;
	}
	else if (Base->ValueType == TypeBool)
	{
		ScriptPosition.Message(MSG_ERROR, "%s is not allowed on type bool", FScanner::TokenName(Token).GetChars());
		delete this;
		return nullptr;
	}
	if (!Base->RequestAddress(ctx, &AddressWritable) || !AddressWritable)
	{
		ScriptPosition.Message(MSG_ERROR, "Expression must be a modifiable value");
		delete this;
		return nullptr;
	}

	return this;
}

ExpEmit FxPostIncrDecr::Emit(VMFunctionBuilder *build)
{
	assert(Token == TK_Incr || Token == TK_Decr);
	assert(ValueType == Base->ValueType && IsNumeric());

	int zero = build->GetConstantInt(0);
	int regtype = ValueType->GetRegType();
	ExpEmit pointer = Base->Emit(build);

	if (!pointer.Target)
	{
		ExpEmit out(build, regtype);
		build->Emit(ValueType->GetLoadOp(), out.RegNum, pointer.RegNum, zero);
		ExpEmit assign(build, regtype);
		if (regtype == REGT_INT)
		{
			build->Emit(OP_ADDI, assign.RegNum, out.RegNum, uint8_t((Token == TK_Incr) ? 1 : -1));
		}
		else
		{
			build->Emit((Token == TK_Incr) ? OP_ADDF_RK : OP_SUBF_RK, assign.RegNum, out.RegNum, build->GetConstantFloat(1.));
		}
		build->Emit(ValueType->GetStoreOp(), pointer.RegNum, assign.RegNum, zero);
		pointer.Free(build);
		assign.Free(build);
		return out;
	}
	else if (NeedResult)
	{
		ExpEmit out(build, regtype);
		if (regtype == REGT_INT)
		{
			build->Emit(OP_MOVE, out.RegNum, pointer.RegNum);
			build->Emit(OP_ADDI, pointer.RegNum, pointer.RegNum, uint8_t((Token == TK_Incr) ? 1 : -1));
		}
		else
		{
			build->Emit(OP_MOVEF, out.RegNum, pointer.RegNum);
			build->Emit((Token == TK_Incr) ? OP_ADDF_RK : OP_SUBF_RK, pointer.RegNum, pointer.RegNum, build->GetConstantFloat(1.));
		}
		pointer.Free(build);
		return out;
	}
	else
	{
		if (regtype == REGT_INT)
		{
			build->Emit(OP_ADDI, pointer.RegNum, pointer.RegNum, uint8_t((Token == TK_Incr) ? 1 : -1));
		}
		else
		{
			build->Emit((Token == TK_Incr) ? OP_ADDF_RK : OP_SUBF_RK, pointer.RegNum, pointer.RegNum, build->GetConstantFloat(1.));
		}
		pointer.Free(build);
		return ExpEmit();
	}
}

//==========================================================================
//
// FxAssign
//
//==========================================================================

FxAssign::FxAssign(FxExpression *base, FxExpression *right, bool ismodify)
: FxExpression(EFX_Assign, base->ScriptPosition), Base(base), Right(right), IsBitWrite(-1), IsModifyAssign(ismodify)
{
	AddressRequested = false;
	AddressWritable = false;
}

FxAssign::~FxAssign()
{
	SAFE_DELETE(Base);
	SAFE_DELETE(Right);
}

/* I don't think we should allow constructs like (a = b) = c;...
bool FxAssign::RequestAddress(FCompileContext &ctx, bool *writable)
{
	AddressRequested = true;
	if (writable != nullptr) *writable = AddressWritable;
	return true;
}
*/

FxExpression *FxAssign::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Base, ctx);

	ValueType = Base->ValueType;

	SAFE_RESOLVE(Right, ctx);

	if (IsModifyAssign && Base->ValueType == TypeBool && Right->ValueType != TypeBool)
	{
		// If the modify operation resulted in a type promotion from bool to int, this must be blocked.
		// (this means, for bool, only &=, ^= and |= are allowed, although DECORATE is more lax.)
		ScriptPosition.Message(MSG_ERROR, "Invalid modify/assign operation with a boolean operand");
		delete this;
		return nullptr;
	}

	// keep the redundant handling for numeric types here to avoid problems with DECORATE.
	// for non-numerics FxTypeCast can be used without issues.
	if (Base->IsNumeric() && Right->IsNumeric())
	{
		if (Right->ValueType != ValueType)
		{
			if (ValueType == TypeBool)
			{
				Right = new FxBoolCast(Right);
			}
			else if (ValueType->GetRegType() == REGT_INT)
			{
				Right = new FxIntCast(Right, ctx.FromDecorate);
			}
			else
			{
				Right = new FxFloatCast(Right);
			}
			SAFE_RESOLVE(Right, ctx);
		}
	}
	else if (Base->ValueType == Right->ValueType)
	{
		if (Base->ValueType->isArray())
		{
			ScriptPosition.Message(MSG_ERROR, "Cannot assign arrays");
			delete this;
			return nullptr;
		}
		else if (Base->IsDynamicArray())
		{
			ScriptPosition.Message(MSG_ERROR, "Cannot assign dynamic arrays, use Copy() or Move() function instead");
			delete this;
			return nullptr;
		}
		if (!Base->IsVector() && Base->ValueType->isStruct())
		{
			ScriptPosition.Message(MSG_ERROR, "Struct assignment not implemented yet");
			delete this;
			return nullptr;
		}
		// Both types are the same so this is ok.
	}
	else if (Right->IsNativeStruct() && Base->ValueType->isRealPointer() && Base->ValueType->toPointer()->PointedType == Right->ValueType)
	{
		// allow conversion of native structs to pointers of the same type. This is necessary to assign elements from global arrays like players, sectors, etc. to local pointers.
		// For all other types this is not needed. Structs are not assignable and classes can only exist as references.
		bool writable;
		Right->RequestAddress(ctx, &writable);
		Right->ValueType = Base->ValueType;
	}
	else
	{
		// pass it to FxTypeCast for complete handling.
		Right = new FxTypeCast(Right, Base->ValueType, false);
		SAFE_RESOLVE(Right, ctx);
	}

	if (!Base->RequestAddress(ctx, &AddressWritable) || !AddressWritable)
	{
		ScriptPosition.Message(MSG_ERROR, "Expression must be a modifiable value");
		delete this;
		return nullptr;
	}

	// Special case: Assignment to a bitfield.
	IsBitWrite = Base->GetBitValue();
	return this;
}

ExpEmit FxAssign::Emit(VMFunctionBuilder *build)
{
	static const uint8_t loadops[] = { OP_LK, OP_LKF, OP_LKS, OP_LKP };
	assert(Base->ValueType->GetRegType() == Right->ValueType->GetRegType());

	ExpEmit pointer = Base->Emit(build);
	Address = pointer;

	ExpEmit result;
	bool intconst = false;
	int intconstval;

	if (Right->isConstant() && Right->ValueType->GetRegType() == REGT_INT)
	{
		intconst = true;
		intconstval = static_cast<FxConstant*>(Right)->GetValue().GetInt();
		result.Konst = true;
		result.RegType = REGT_INT;
	}
	else
	{
		result = Right->Emit(build);
	}
	assert(result.RegType <= REGT_TYPE);

	if (pointer.Target)
	{
		if (result.Konst)
		{
			if (intconst) build->EmitLoadInt(pointer.RegNum, intconstval);
			else build->Emit(loadops[result.RegType], pointer.RegNum, result.RegNum);
		}
		else
		{
			build->Emit(Right->ValueType->GetMoveOp(), pointer.RegNum, result.RegNum);
		}
	}
	else
	{
		if (result.Konst)
		{
			ExpEmit temp(build, result.RegType);
			if (intconst) build->EmitLoadInt(temp.RegNum, intconstval);
			else build->Emit(loadops[result.RegType], temp.RegNum, result.RegNum);
			result.Free(build);
			result = temp;
		}

		if (IsBitWrite == -1)
		{
			build->Emit(Base->ValueType->GetStoreOp(), pointer.RegNum, result.RegNum, build->GetConstantInt(0));
		}
		else
		{
			build->Emit(OP_SBIT, pointer.RegNum, result.RegNum, 1 << IsBitWrite);
		}

	}

	if (AddressRequested)
	{
		result.Free(build);
		return pointer;
	}

	pointer.Free(build);
	return result;
}

//==========================================================================
//
//	FxAssignSelf
//
//==========================================================================

FxAssignSelf::FxAssignSelf(const FScriptPosition &pos)
: FxExpression(EFX_AssignSelf, pos)
{
	Assignment = nullptr;
}

FxExpression *FxAssignSelf::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();

	// This should never happen if FxAssignSelf is used correctly
	assert(Assignment != nullptr);

	ValueType = Assignment->ValueType;

	return this;
}

ExpEmit FxAssignSelf::Emit(VMFunctionBuilder *build)
{
	assert(ValueType == Assignment->ValueType);
	ExpEmit pointer = Assignment->Address; // FxAssign should have already emitted it
	if (!pointer.Target)
	{
		ExpEmit out(build, ValueType->GetRegType(), ValueType->GetRegCount());
		if (Assignment->IsBitWrite != -1)
		{
			build->Emit(OP_LBIT, out.RegNum, pointer.RegNum, 1 << Assignment->IsBitWrite);
		}
		else
		{
			build->Emit(ValueType->GetLoadOp(), out.RegNum, pointer.RegNum, build->GetConstantInt(0));
		}
		return out;
	}
	else
	{
		return pointer;
	}
}


//==========================================================================
//
//
//
//==========================================================================

FxMultiAssign::FxMultiAssign(FArgumentList &base, FxExpression *right, const FScriptPosition &pos)
	:FxExpression(EFX_MultiAssign, pos)
{
	Base = std::move(base);
	Right = right;
	LocalVarContainer = new FxCompoundStatement(ScriptPosition);
}

//==========================================================================
//
//
//
//==========================================================================

FxMultiAssign::~FxMultiAssign()
{
	SAFE_DELETE(Right);
	SAFE_DELETE(LocalVarContainer);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxMultiAssign::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Right, ctx);
	if (Right->ExprType != EFX_VMFunctionCall)
	{
		Right->ScriptPosition.Message(MSG_ERROR, "Function call expected on right side of multi-assigment");
		delete this;
		return nullptr;
	}
	auto VMRight = static_cast<FxVMFunctionCall *>(Right);
	auto rets = VMRight->GetReturnTypes();
	if (rets.Size() < Base.Size())
	{
		Right->ScriptPosition.Message(MSG_ERROR, "Insufficient returns in function %s", VMRight->Function->SymbolName.GetChars());
		delete this;
		return nullptr;
	}
	// Pack the generated data (temp local variables for the results and necessary type casts and single assignments) into a compound statement for easier management.
	for (unsigned i = 0; i < Base.Size(); i++)
	{
		auto singlevar = new FxLocalVariableDeclaration(rets[i], NAME_None, nullptr, 0, ScriptPosition);
		LocalVarContainer->Add(singlevar);
		Base[i] = Base[i]->Resolve(ctx);
		ABORT(Base[i]);
		auto varaccess = new FxLocalVariable(singlevar, ScriptPosition);
		auto assignee = new FxTypeCast(varaccess, Base[i]->ValueType, false);
		LocalVarContainer->Add(new FxAssign(Base[i], assignee, false));
		// now temporary variable owns the current item
		Base[i] = nullptr;
	}
	auto x = LocalVarContainer->Resolve(ctx);
	LocalVarContainer = nullptr;
	ABORT(x);
	LocalVarContainer = static_cast<FxCompoundStatement*>(x);
	static_cast<FxVMFunctionCall *>(Right)->AssignCount = Base.Size();
	ValueType = TypeVoid;
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxMultiAssign::Emit(VMFunctionBuilder *build)
{
	Right->Emit(build);
	for (unsigned i = 0; i < Base.Size(); i++)
	{
		LocalVarContainer->LocalVars[i]->SetReg(static_cast<FxVMFunctionCall *>(Right)->ReturnRegs[i]);
	}
	static_cast<FxVMFunctionCall *>(Right)->ReturnRegs.Clear();
	static_cast<FxVMFunctionCall *>(Right)->ReturnRegs.ShrinkToFit();
	return LocalVarContainer->Emit(build);
}

//==========================================================================
//
//
//
//==========================================================================

FxBinary::FxBinary(int o, FxExpression *l, FxExpression *r)
: FxExpression(EFX_Binary, l->ScriptPosition)
{
	Operator=o;
	left=l;
	right=r;
}

//==========================================================================
//
//
//
//==========================================================================

FxBinary::~FxBinary()
{
	SAFE_DELETE(left);
	SAFE_DELETE(right);
}

//==========================================================================
//
//
//
//==========================================================================

bool FxBinary::Promote(FCompileContext &ctx, bool forceint)
{
	// math operations of unsigned ints results in an unsigned int. (16 and 8 bit values never get here, they get promoted to regular ints elsewhere already.)
	if (left->ValueType == TypeUInt32 && right->ValueType == TypeUInt32)
	{
		ValueType = TypeUInt32;
	}
	else if (left->IsInteger() && right->IsInteger())
	{
		ValueType = TypeSInt32;		// Addition and subtraction forces all integer-derived types to signed int.
	}
	else if (!forceint)
	{
		ValueType = TypeFloat64;
		if (left->IsFloat() && right->IsInteger())
		{
			right = (new FxFloatCast(right))->Resolve(ctx);
		}
		else if (left->IsInteger() && right->IsFloat())
		{
			left = (new FxFloatCast(left))->Resolve(ctx);
		}
	}
	else if (ctx.FromDecorate)
	{
		// For DECORATE which allows floats here. ZScript does not.
		if (left->IsFloat())
		{
			left = new FxIntCast(left, ctx.FromDecorate);
			left = left->Resolve(ctx);
		}
		if (right->IsFloat())
		{
			right = new FxIntCast(right, ctx.FromDecorate);
			right = right->Resolve(ctx);
		}
		if (left == nullptr || right == nullptr)
		{
			delete this;
			return false;
		}
		ValueType = TypeSInt32;

	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Integer operand expected");
		delete this;
		return false;
	}
	return true;
}

//==========================================================================
//
//
//
//==========================================================================

FxAddSub::FxAddSub(int o, FxExpression *l, FxExpression *r)
: FxBinary(o, l, r)
{
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxAddSub::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();

	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	if (!left || !right)
	{
		delete this;
		return nullptr;
	}

	if (left->ValueType == TypeTextureID && right->IsInteger())
	{
		ValueType = TypeTextureID;
	}
	else if (left->ValueType == TypeState && right->IsInteger() && Operator == '+' && !left->isConstant())
	{
		// This is the only special case of pointer addition that will be accepted - because it is used quite often in the existing game code.
		ValueType = TypeState;
		right = new FxMulDiv('*', right, new FxConstant((int)sizeof(FState), ScriptPosition));	// multiply by size here, so that constants can be better optimized.
		right = right->Resolve(ctx);
		ABORT(right);
	}
	else if (left->IsVector() && right->IsVector())
	{
		// a vector2 can be added to or subtracted from a vector 3 but it needs to be the right operand.
		if (left->ValueType == right->ValueType || (left->ValueType == TypeVector3 && right->ValueType == TypeVector2))
		{
			ValueType = left->ValueType;
		}
		else
		{
			goto error;
		}
	}
	else if (left->IsNumeric() && right->IsNumeric())
	{
		Promote(ctx);
	}
	else
	{
		// To check: It may be that this could pass in DECORATE, although setting TypeVoid here would pretty much prevent that.
		goto error;
	}

	if (left->isConstant() && right->isConstant())
	{
		if (IsFloat())
		{
			double v;
			double v1 = static_cast<FxConstant *>(left)->GetValue().GetFloat();
			double v2 = static_cast<FxConstant *>(right)->GetValue().GetFloat();

			v =	Operator == '+'? v1 + v2 : 
				Operator == '-'? v1 - v2 : 0;

			FxExpression *e = new FxConstant(v, ScriptPosition);
			delete this;
			return e;
		}
		else
		{
			int v;
			int v1 = static_cast<FxConstant *>(left)->GetValue().GetInt();
			int v2 = static_cast<FxConstant *>(right)->GetValue().GetInt();

			v =	Operator == '+'? v1 + v2 : 
				Operator == '-'? v1 - v2 : 0;

			FxExpression *e = new FxConstant(v, ScriptPosition);
			delete this;
			return e;

		}
	}
	return this;

error:
	ScriptPosition.Message(MSG_ERROR, "Incompatible operands for %s", Operator == '+' ? "addition" : "subtraction");
	delete this;
	return nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxAddSub::Emit(VMFunctionBuilder *build)
{
	assert(Operator == '+' || Operator == '-');
	ExpEmit op1 = left->Emit(build);
	ExpEmit op2 = right->Emit(build);
	ExpEmit to;
	if (Operator == '+')
	{
		if (op1.RegType == REGT_POINTER)
		{
			assert(!op1.Konst);
			assert(op2.RegType == REGT_INT);
			op1.Free(build);
			op2.Free(build);
			ExpEmit opout(build, REGT_POINTER);
			build->Emit(op2.Konst? OP_ADDA_RK : OP_ADDA_RR, opout.RegNum, op1.RegNum, op2.RegNum);
			return opout;
		}
		// Since addition is commutative, only the second operand may be a constant.
		if (op1.Konst)
		{
			swapvalues(op1, op2);
		}
		assert(!op1.Konst);
		op1.Free(build);
		op2.Free(build);
		to = ExpEmit(build, ValueType->GetRegType(), ValueType->GetRegCount());
		if (IsVector())
		{
			assert(op1.RegType == REGT_FLOAT && op2.RegType == REGT_FLOAT);
			build->Emit(right->ValueType == TypeVector2? OP_ADDV2_RR : OP_ADDV3_RR, to.RegNum, op1.RegNum, op2.RegNum);
			if (left->ValueType == TypeVector3 && right->ValueType == TypeVector2 && to.RegNum != op1.RegNum)
			{
				// must move the z-coordinate
				build->Emit(OP_MOVEF, to.RegNum + 2, op1.RegNum + 2);
			}
			return to;
		}
		else if (ValueType->GetRegType() == REGT_FLOAT)
		{
			assert(op1.RegType == REGT_FLOAT && op2.RegType == REGT_FLOAT);
			build->Emit(op2.Konst ? OP_ADDF_RK : OP_ADDF_RR, to.RegNum, op1.RegNum, op2.RegNum);
			return to;
		}
		else
		{
			assert(ValueType->GetRegType() == REGT_INT);
			assert(op1.RegType == REGT_INT && op2.RegType == REGT_INT);
			build->Emit(op2.Konst ? OP_ADD_RK : OP_ADD_RR, to.RegNum, op1.RegNum, op2.RegNum);
			if (ValueType == TypeTextureID) goto texcheck;
			return to;
		}
	}
	else
	{
		// Subtraction is not commutative, so either side may be constant (but not both).
		assert(!op1.Konst || !op2.Konst);
		op1.Free(build);
		op2.Free(build);
		to = ExpEmit(build, ValueType->GetRegType(), ValueType->GetRegCount());
		if (IsVector())
		{
			assert(op1.RegType == REGT_FLOAT && op2.RegType == REGT_FLOAT);
			build->Emit(right->ValueType == TypeVector2 ? OP_SUBV2_RR : OP_SUBV3_RR, to.RegNum, op1.RegNum, op2.RegNum);
			return to;
		}
		else if (ValueType->GetRegType() == REGT_FLOAT)
		{
			assert(op1.RegType == REGT_FLOAT && op2.RegType == REGT_FLOAT);
			build->Emit(op1.Konst ? OP_SUBF_KR : op2.Konst ? OP_SUBF_RK : OP_SUBF_RR, to.RegNum, op1.RegNum, op2.RegNum);
			return to;
		}
		else
		{
			assert(ValueType->GetRegType() == REGT_INT);
			assert(op1.RegType == REGT_INT && op2.RegType == REGT_INT);
			build->Emit(op1.Konst ? OP_SUB_KR : op2.Konst ? OP_SUB_RK : OP_SUB_RR, to.RegNum, op1.RegNum, op2.RegNum);
			if (ValueType == TypeTextureID) goto texcheck;
			return to;
		}
	}

texcheck:
	// Do a bounds check for the texture index. Note that count can change at run time so this needs to read the value from the texture manager.
	auto * ptr = (FArray*)&TexMan.Textures;
	auto * countptr = &ptr->Count;
	ExpEmit bndp(build, REGT_POINTER);
	ExpEmit bndc(build, REGT_INT);
	build->Emit(OP_LKP, bndp.RegNum, build->GetConstantAddress(countptr));
	build->Emit(OP_LW, bndc.RegNum, bndp.RegNum, build->GetConstantInt(0));
	build->Emit(OP_BOUND_R, to.RegNum, bndc.RegNum);
	bndp.Free(build);
	bndc.Free(build);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxMulDiv::FxMulDiv(int o, FxExpression *l, FxExpression *r)
: FxBinary(o, l, r)
{
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxMulDiv::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();

	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	if (!left || !right)
	{
		delete this;
		return nullptr;
	}
	if (!left->ValueType || !right->ValueType)
	{
		ScriptPosition.Message(MSG_ERROR, "ValueType not set");
		delete this;
		return nullptr;
	}

	if (left->IsVector() || right->IsVector())
	{
		switch (Operator)
		{
		case '/':
			// For division, the vector must be the first operand.
			if (right->IsVector()) goto error;

		case '*':
			if (left->IsVector() && right->IsNumeric())
			{
				if (right->IsInteger())
				{
					right = new FxFloatCast(right);
					right = right->Resolve(ctx);
					if (right == nullptr)
					{
						delete this;
						return nullptr;
					}
				}
				ValueType = left->ValueType;
				break;
			}
			else if (right->IsVector() && left->IsNumeric())
			{
				if (left->IsInteger())
				{
					left = new FxFloatCast(left);
					left = left->Resolve(ctx);
					if (left == nullptr)
					{
						delete this;
						return nullptr;
					}
				}
				ValueType = right->ValueType;
				break;
			}
			// Incompatible operands, intentional fall-through

		default:
			// Vector modulus is not permitted
			goto error;

		}
	}
	else if (left->IsNumeric() && right->IsNumeric())
	{
		Promote(ctx);
	}
	else
	{
		// To check: It may be that this could pass in DECORATE, although setting TypeVoid here would pretty much prevent that.
		goto error;
	}

	if (left->isConstant() && right->isConstant())
	{
		if (IsFloat())
		{
			double v;
			double v1 = static_cast<FxConstant *>(left)->GetValue().GetFloat();
			double v2 = static_cast<FxConstant *>(right)->GetValue().GetFloat();

			if (Operator != '*' && v2 == 0)
			{
				ScriptPosition.Message(MSG_ERROR, "Division by 0");
				delete this;
				return nullptr;
			}

			v =	Operator == '*'? v1 * v2 : 
				Operator == '/'? v1 / v2 : 
				Operator == '%'? fmod(v1, v2) : 0;

			FxExpression *e = new FxConstant(v, ScriptPosition);
			delete this;
			return e;
		}
		else
		{
			int v;
			int v1 = static_cast<FxConstant *>(left)->GetValue().GetInt();
			int v2 = static_cast<FxConstant *>(right)->GetValue().GetInt();

			if (Operator != '*' && v2 == 0)
			{
				ScriptPosition.Message(MSG_ERROR, "Division by 0");
				delete this;
				return nullptr;
			}

			v =	Operator == '*'? v1 * v2 : 
				Operator == '/'? v1 / v2 : 
				Operator == '%'? v1 % v2 : 0;

			FxExpression *e = new FxConstant(v, ScriptPosition);
			delete this;
			return e;

		}
	}
	return this;

error:
	ScriptPosition.Message(MSG_ERROR, "Incompatible operands for %s", Operator == '*' ? "multiplication" : Operator == '%' ? "modulus" : "division");
	delete this;
	return nullptr;

}


//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxMulDiv::Emit(VMFunctionBuilder *build)
{
	ExpEmit op1 = left->Emit(build);
	ExpEmit op2 = right->Emit(build);

	if (IsVector())
	{
		assert(Operator != '%');
		if (right->IsVector())
		{
			swapvalues(op1, op2);
		}
		int op;
		if (op2.Konst)
		{
			op = Operator == '*' ? (ValueType == TypeVector2 ? OP_MULVF2_RK : OP_MULVF3_RK) : (ValueType == TypeVector2 ? OP_DIVVF2_RK : OP_DIVVF3_RK);
		}
		else
		{
			op = Operator == '*' ? (ValueType == TypeVector2 ? OP_MULVF2_RR : OP_MULVF3_RR) : (ValueType == TypeVector2 ? OP_DIVVF2_RR : OP_DIVVF3_RR);
		}
		op1.Free(build);
		op2.Free(build);
		ExpEmit to(build, ValueType->GetRegType(), ValueType->GetRegCount());
		build->Emit(op, to.RegNum, op1.RegNum, op2.RegNum);
		return to;
	}

	if (Operator == '*')
	{
		// Multiplication is commutative, so only the second operand may be constant.
		if (op1.Konst)
		{
			swapvalues(op1, op2);
		}
		assert(!op1.Konst);
		op1.Free(build);
		op2.Free(build);
		ExpEmit to(build, ValueType->GetRegType());
		if (ValueType->GetRegType() == REGT_FLOAT)
		{
			assert(op1.RegType == REGT_FLOAT && op2.RegType == REGT_FLOAT);
			build->Emit(op2.Konst ? OP_MULF_RK : OP_MULF_RR, to.RegNum, op1.RegNum, op2.RegNum);
			return to;
		}
		else
		{
			assert(ValueType->GetRegType() == REGT_INT);
			assert(op1.RegType == REGT_INT && op2.RegType == REGT_INT);
			build->Emit(op2.Konst ? OP_MUL_RK : OP_MUL_RR, to.RegNum, op1.RegNum, op2.RegNum);
			return to;
		}
	}
	else
	{
		// Division is not commutative, so either side may be constant (but not both).
		assert(!op1.Konst || !op2.Konst);
		assert(Operator == '%' || Operator == '/');
		op1.Free(build);
		op2.Free(build);
		ExpEmit to(build, ValueType->GetRegType());
		if (ValueType->GetRegType() == REGT_FLOAT)
		{
			assert(op1.RegType == REGT_FLOAT && op2.RegType == REGT_FLOAT);
			build->Emit(Operator == '/' ? (op1.Konst ? OP_DIVF_KR : op2.Konst ? OP_DIVF_RK : OP_DIVF_RR)
				: (op1.Konst ? OP_MODF_KR : op2.Konst ? OP_MODF_RK : OP_MODF_RR),
				to.RegNum, op1.RegNum, op2.RegNum);
			return to;
		}
		else
		{
			assert(ValueType->GetRegType() == REGT_INT);
			assert(op1.RegType == REGT_INT && op2.RegType == REGT_INT);
			if (ValueType == TypeUInt32)
			{
				build->Emit(Operator == '/' ? (op1.Konst ? OP_DIVU_KR : op2.Konst ? OP_DIVU_RK : OP_DIVU_RR)
					: (op1.Konst ? OP_MODU_KR : op2.Konst ? OP_MODU_RK : OP_MODU_RR),
					to.RegNum, op1.RegNum, op2.RegNum);
			}
			else
			{
				build->Emit(Operator == '/' ? (op1.Konst ? OP_DIV_KR : op2.Konst ? OP_DIV_RK : OP_DIV_RR)
					: (op1.Konst ? OP_MOD_KR : op2.Konst ? OP_MOD_RK : OP_MOD_RR),
					to.RegNum, op1.RegNum, op2.RegNum);
			}
			return to;
		}
	}
}

//==========================================================================
//
//
//
//==========================================================================

FxPow::FxPow(FxExpression *l, FxExpression *r)
	: FxBinary(TK_MulMul, new FxFloatCast(l), new FxFloatCast(r))
{
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxPow::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();

	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	if (!left || !right)
	{
		delete this;
		return nullptr;
	}
	if (!left->IsNumeric() || !right->IsNumeric())
	{
		ScriptPosition.Message(MSG_ERROR, "Numeric type expected for '**'");
		delete this;
		return nullptr;
	}
	if (!left->IsFloat())
	{
		left = (new FxFloatCast(left))->Resolve(ctx);
		ABORT(left);
	}
	if (!right->IsFloat())
	{
		right = (new FxFloatCast(right))->Resolve(ctx);
		ABORT(right);
	}
	ValueType = TypeFloat64;
	if (left->isConstant() && right->isConstant())
	{
		double v1 = static_cast<FxConstant *>(left)->GetValue().GetFloat();
		double v2 = static_cast<FxConstant *>(right)->GetValue().GetFloat();
		return new FxConstant(g_pow(v1, v2), left->ScriptPosition);
	}
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxPow::Emit(VMFunctionBuilder *build)
{
	ExpEmit op1 = left->Emit(build);
	ExpEmit op2 = right->Emit(build);

	// Pow is not commutative, so either side may be constant (but not both).
	assert(!op1.Konst || !op2.Konst);
	op1.Free(build);
	op2.Free(build);
	assert(op1.RegType == REGT_FLOAT && op2.RegType == REGT_FLOAT);
	ExpEmit to(build, REGT_FLOAT);
	build->Emit((op1.Konst ? OP_POWF_KR : op2.Konst ? OP_POWF_RK : OP_POWF_RR),	to.RegNum, op1.RegNum, op2.RegNum);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxCompareRel::FxCompareRel(int o, FxExpression *l, FxExpression *r)
: FxBinary(o, l, r)
{
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxCompareRel::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();

	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	if (!left || !right)
	{
		delete this;
		return nullptr;
	}

	FxExpression *x;
	if (left->IsNumeric() && right->ValueType == TypeString && (x = StringConstToChar(right)))
	{
		delete right;
		right = x;
	}
	else if (right->IsNumeric() && left->ValueType == TypeString && (x = StringConstToChar(left)))
	{
		delete left;
		left = x;
	}

	if (left->ValueType == TypeString || right->ValueType == TypeString)
	{
		if (left->ValueType != TypeString)
		{
			left = new FxStringCast(left);
			left = left->Resolve(ctx);
			if (left == nullptr)
			{
				delete this;
				return nullptr;
			}
		}
		if (right->ValueType != TypeString)
		{
			right = new FxStringCast(right);
			right = right->Resolve(ctx);
			if (right == nullptr)
			{
				delete this;
				return nullptr;
			}
		}
		ValueType = TypeString;
	}
	else if (left->IsNumeric() && right->IsNumeric())
	{
		Promote(ctx);
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Incompatible operands for relative comparison");
		delete this;
		return nullptr;
	}

	if (left->isConstant() && right->isConstant())
	{
		int v;

		if (ValueType == TypeString)
		{
			FString v1 = static_cast<FxConstant *>(left)->GetValue().GetString();
			FString v2 = static_cast<FxConstant *>(right)->GetValue().GetString();
			int res = v1.Compare(v2);
			v = Operator == '<' ? res < 0 :
				Operator == '>' ? res > 0 :
				Operator == TK_Geq ? res >= 0 :
				Operator == TK_Leq ? res <= 0 : 0;
		}
		else if (IsFloat())
		{
			double v1 = static_cast<FxConstant *>(left)->GetValue().GetFloat();
			double v2 = static_cast<FxConstant *>(right)->GetValue().GetFloat();
			v =	Operator == '<'? v1 < v2 : 
				Operator == '>'? v1 > v2 : 
				Operator == TK_Geq? v1 >= v2 : 
				Operator == TK_Leq? v1 <= v2 : 0;
		}
		else if (ValueType == TypeUInt32)
		{
			int v1 = static_cast<FxConstant *>(left)->GetValue().GetUInt();
			int v2 = static_cast<FxConstant *>(right)->GetValue().GetUInt();
			v =	Operator == '<'? v1 < v2 : 
				Operator == '>'? v1 > v2 : 
				Operator == TK_Geq? v1 >= v2 : 
				Operator == TK_Leq? v1 <= v2 : 0;
		}
		else 
		{
			int v1 = static_cast<FxConstant *>(left)->GetValue().GetInt();
			int v2 = static_cast<FxConstant *>(right)->GetValue().GetInt();
			v = Operator == '<' ? v1 < v2 :
				Operator == '>' ? v1 > v2 :
				Operator == TK_Geq ? v1 >= v2 :
				Operator == TK_Leq ? v1 <= v2 : 0;
		}
		FxExpression *e = new FxConstant(v, ScriptPosition);
		delete this;
		return e;
	}
	CompareType = ValueType;	// needs to be preserved for detection of unsigned compare.
	ValueType = TypeBool;
	return this;
}


//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxCompareRel::EmitCommon(VMFunctionBuilder *build, bool forcompare, bool invert)
{
	ExpEmit op1 = left->Emit(build);
	ExpEmit op2 = right->Emit(build);
	assert(op1.RegType == op2.RegType);
	assert(!op1.Konst || !op2.Konst);

	if (op1.RegType == REGT_STRING)
	{
		ExpEmit to(build, REGT_INT);
		int a = Operator == '<' ? CMP_LT :
			Operator == '>' ? CMP_LE | CMP_CHECK :
			Operator == TK_Geq ? CMP_LT | CMP_CHECK : CMP_LE;

		if (op1.Konst)
		{
			a |= CMP_BK;
		}
		else
		{
			op1.Free(build);
		}
		if (op2.Konst)
		{
			a |= CMP_CK;
		}
		else
		{
			op2.Free(build);
		}
		if (invert) a ^= CMP_CHECK;

		if (!forcompare) build->Emit(OP_LI, to.RegNum, 0, 0);
		build->Emit(OP_CMPS, a, op1.RegNum, op2.RegNum);
		if (!forcompare)
		{
			build->Emit(OP_JMP, 1);
			build->Emit(OP_LI, to.RegNum, 1);
		}
		return to;
	}
	else
	{
		assert(op1.RegType == REGT_INT || op1.RegType == REGT_FLOAT);
		assert(Operator == '<' || Operator == '>' || Operator == TK_Geq || Operator == TK_Leq);
		static const VM_UBYTE InstrMap[][4] =
		{
			{ OP_LT_RR, OP_LTF_RR, OP_LTU_RR, 0 },	// <
			{ OP_LE_RR, OP_LEF_RR, OP_LEU_RR, 1 },	// >
			{ OP_LT_RR, OP_LTF_RR, OP_LTU_RR, 1 },	// >=
			{ OP_LE_RR, OP_LEF_RR, OP_LEU_RR, 0 }	// <=
		};
		int instr, check;
		ExpEmit to(build, REGT_INT);
		int index = Operator == '<' ? 0 :
			Operator == '>' ? 1 :
			Operator == TK_Geq ? 2 : 3;

		int mode = op1.RegType == REGT_FLOAT ? 1 : CompareType == TypeUInt32 ? 2 : 0;
		instr = InstrMap[index][mode];
		check = InstrMap[index][3];
		if (op2.Konst)
		{
			instr += 1;
		}
		else
		{
			op2.Free(build);
		}
		if (op1.Konst)
		{
			instr += 2;
		}
		else
		{
			op1.Free(build);
		}
		if (invert) check ^= 1;

		// See FxBoolCast for comments, since it's the same thing.
		if (!forcompare) build->Emit(OP_LI, to.RegNum, 0, 0);
		build->Emit(instr, check, op1.RegNum, op2.RegNum);
		if (!forcompare)
		{
			build->Emit(OP_JMP, 1);
			build->Emit(OP_LI, to.RegNum, 1);
		}
		return to;
	}
}

ExpEmit FxCompareRel::Emit(VMFunctionBuilder *build)
{
	return EmitCommon(build, false, false);
}

void FxCompareRel::EmitCompare(VMFunctionBuilder *build, bool invert, TArray<size_t> &patchspots_yes, TArray<size_t> &patchspots_no)
{
	ExpEmit emit = EmitCommon(build, true, invert);
	emit.Free(build);
	patchspots_no.Push(build->Emit(OP_JMP, 0));
}

//==========================================================================
//
//
//
//==========================================================================

FxCompareEq::FxCompareEq(int o, FxExpression *l, FxExpression *r)
: FxBinary(o, l, r)
{
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxCompareEq::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();

	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	if (!left || !right)
	{
		delete this;
		return nullptr;
	}

	if (left->ValueType != right->ValueType)	// identical types are always comparable, if they can be placed in a register, so we can save most checks if this is the case.
	{
		FxExpression *x;
		if (left->IsNumeric() && right->ValueType == TypeString && (x = StringConstToChar(right)))
		{
			delete right;
			right = x;
		}
		else if (right->IsNumeric() && left->ValueType == TypeString && (x = StringConstToChar(left)))
		{
			delete left;
			left = x;
		}
		// Special cases: Compare strings and names with names, sounds, colors, state labels and class types.
		// These are all types a string can be implicitly cast into, so for convenience, so they should when doing a comparison.
		if ((left->ValueType == TypeString || left->ValueType == TypeName) &&
			(right->ValueType == TypeName || right->ValueType == TypeSound || right->ValueType == TypeColor || right->ValueType->isClassPointer() || right->ValueType == TypeStateLabel))
		{
			left = new FxTypeCast(left, right->ValueType, false, true);
			left = left->Resolve(ctx);
			ABORT(left);
			ValueType = right->ValueType;
		}
		else if ((right->ValueType == TypeString || right->ValueType == TypeName) &&
			(left->ValueType == TypeName || left->ValueType == TypeSound || left->ValueType == TypeColor || left->ValueType->isClassPointer() || left->ValueType == TypeStateLabel))
		{
			right = new FxTypeCast(right, left->ValueType, false, true);
			right = right->Resolve(ctx);
			ABORT(right);
			ValueType = left->ValueType;
		}
		else if (left->IsNumeric() && right->IsNumeric())
		{
			Promote(ctx);
		}
		// allows comparing state labels with null pointers.
		else if (left->ValueType == TypeStateLabel && right->ValueType == TypeNullPtr)
		{
			right = new FxTypeCast(right, TypeStateLabel, false);
			SAFE_RESOLVE(right, ctx);
		}
		else if (right->ValueType == TypeStateLabel && left->ValueType == TypeNullPtr)
		{
			left = new FxTypeCast(left, TypeStateLabel, false);
			SAFE_RESOLVE(left, ctx);
		}
		else if (left->ValueType->GetRegType() == REGT_POINTER && right->ValueType->GetRegType() == REGT_POINTER)
		{
			if (left->ValueType != right->ValueType && right->ValueType != TypeNullPtr && left->ValueType != TypeNullPtr &&
				!AreCompatiblePointerTypes(left->ValueType, right->ValueType, true))
			{
				goto error;
			}
		}
		else if (left->IsPointer() && left->ValueType->toPointer()->PointedType == right->ValueType)
		{
			bool writable;
			if (!right->RequestAddress(ctx, &writable)) goto error;
		}
		else if (right->IsPointer() && right->ValueType->toPointer()->PointedType == left->ValueType)
		{
			bool writable;
			if (!left->RequestAddress(ctx, &writable)) goto error;
		}
		else
		{
			goto error;
		}
	}
	else if (left->ValueType->GetRegType() == REGT_NIL)
	{
		goto error;
	}
	else
	{
		ValueType = left->ValueType;
	}

	if (Operator == TK_ApproxEq && ValueType->GetRegType() != REGT_FLOAT && ValueType->GetRegType() != REGT_STRING)
	{
		// Only floats, vectors and strings have handling for '~==', for all other types this is an error.
		goto error;
	}

	if (left->isConstant() && right->isConstant())
	{
		int v;

		if (ValueType == TypeString)
		{
			FString v1 = static_cast<FxConstant *>(left)->GetValue().GetString();
			FString v2 = static_cast<FxConstant *>(right)->GetValue().GetString();
			if (Operator == TK_ApproxEq) v = !v1.CompareNoCase(v2);
			else
			{
				v = !!v1.Compare(v2);
				if (Operator == TK_Eq) v = !v;
			}
		}
		else if (ValueType->GetRegType() == REGT_FLOAT)
		{
			double v1 = static_cast<FxConstant *>(left)->GetValue().GetFloat();
			double v2 = static_cast<FxConstant *>(right)->GetValue().GetFloat();
			v = Operator == TK_Eq? v1 == v2 : Operator == TK_Neq? v1 != v2 : fabs(v1-v2) < VM_EPSILON;
		}
		else
		{
			int v1 = static_cast<FxConstant *>(left)->GetValue().GetInt();
			int v2 = static_cast<FxConstant *>(right)->GetValue().GetInt();
			v = Operator == TK_Eq? v1 == v2 : v1 != v2;
		}
		FxExpression *e = new FxConstant(v, ScriptPosition);
		delete this;
		return e;
	}
	else
	{
		// also simplify comparisons against zero. For these a bool cast/unary not on the other value will do just as well and create better code.
		if (Operator != TK_ApproxEq)
		{
			if (left->isConstant())
			{
				bool leftisnull;
				switch (left->ValueType->GetRegType())
				{
				case REGT_INT:
					leftisnull = static_cast<FxConstant *>(left)->GetValue().GetInt() == 0;
					break;

				case REGT_FLOAT:
					assert(left->ValueType->GetRegCount() == 1);	// vectors should not be able to get here.
					leftisnull = static_cast<FxConstant *>(left)->GetValue().GetFloat() == 0;
					break;

				case REGT_POINTER:
					leftisnull = static_cast<FxConstant *>(left)->GetValue().GetPointer() == nullptr;
					break;

				default:
					leftisnull = false;
				}
				if (leftisnull)
				{
					FxExpression *x;
					if (Operator == TK_Eq) x = new FxUnaryNotBoolean(right);
					else x = new FxBoolCast(right);
					right = nullptr;
					delete this;
					return x->Resolve(ctx);
				}

			}
			if (right->isConstant())
			{
				bool rightisnull;
				switch (right->ValueType->GetRegType())
				{
				case REGT_INT:
					rightisnull = static_cast<FxConstant *>(right)->GetValue().GetInt() == 0;
					break;

				case REGT_FLOAT:
					assert(right->ValueType->GetRegCount() == 1);	// vectors should not be able to get here.
					rightisnull = static_cast<FxConstant *>(right)->GetValue().GetFloat() == 0;
					break;

				case REGT_POINTER:
					rightisnull = static_cast<FxConstant *>(right)->GetValue().GetPointer() == nullptr;
					break;

				default:
					rightisnull = false;
				}
				if (rightisnull)
				{
					FxExpression *x;
					if (Operator == TK_Eq) x = new FxUnaryNotBoolean(left);
					else x = new FxBoolCast(left);
					left = nullptr;
					delete this;
					return x->Resolve(ctx);
				}
			}
		}
	}
	ValueType = TypeBool;
	return this;

error:
	ScriptPosition.Message(MSG_ERROR, "Incompatible operands for %s comparison", Operator == TK_Eq ? "==" : Operator == TK_Neq ? "!=" : "~==");
	delete this;
	return nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxCompareEq::EmitCommon(VMFunctionBuilder *build, bool forcompare, bool invert)
{
	ExpEmit op1 = left->Emit(build);
	ExpEmit op2 = right->Emit(build);
	assert(op1.RegType == op2.RegType);
	int instr;

	if (op1.RegType == REGT_STRING)
	{
		ExpEmit to(build, REGT_INT);
		assert(Operator == TK_Eq || Operator == TK_Neq || Operator == TK_ApproxEq);
		int a = Operator == TK_Eq ? CMP_EQ :
			Operator == TK_Neq ? CMP_EQ | CMP_CHECK : CMP_EQ | CMP_APPROX;

		if (op1.Konst) a |= CMP_BK;
		if (op2.Konst) a |= CMP_CK;
		if (invert) a ^= CMP_CHECK;

		if (!forcompare) build->Emit(OP_LI, to.RegNum, 0, 0);
		build->Emit(OP_CMPS, a, op1.RegNum, op2.RegNum);
		if (!forcompare)
		{
			build->Emit(OP_JMP, 1);
			build->Emit(OP_LI, to.RegNum, 1);
		}
		op1.Free(build);
		op2.Free(build);
		return to;
	}
	else
	{

		// Only the second operand may be constant.
		if (op1.Konst)
		{
			swapvalues(op1, op2);
		}
		assert(!op1.Konst);
		assert(op1.RegCount >= 1 && op1.RegCount <= 3);

		ExpEmit to(build, REGT_INT);

		static int flops[] = { OP_EQF_R, OP_EQV2_R, OP_EQV3_R };
		instr = op1.RegType == REGT_INT ? OP_EQ_R :
			op1.RegType == REGT_FLOAT ? flops[op1.RegCount - 1] :
			OP_EQA_R;
		op1.Free(build);
		if (!op2.Konst)
		{
			op2.Free(build);
		}
		else
		{
			instr += 1;
		}

		// See FxUnaryNotBoolean for comments, since it's the same thing.
		if (!forcompare) build->Emit(OP_LI, to.RegNum, 0, 0);
		build->Emit(instr, int(invert) ^ (Operator == TK_ApproxEq ? CMP_APPROX : ((Operator != TK_Eq) ? CMP_CHECK : 0)), op1.RegNum, op2.RegNum);
		if (!forcompare)
		{
			build->Emit(OP_JMP, 1);
			build->Emit(OP_LI, to.RegNum, 1);
		}
		return to;
	}
}

ExpEmit FxCompareEq::Emit(VMFunctionBuilder *build)
{
	return EmitCommon(build, false, false);
}

void FxCompareEq::EmitCompare(VMFunctionBuilder *build, bool invert, TArray<size_t> &patchspots_yes, TArray<size_t> &patchspots_no)
{
	ExpEmit emit = EmitCommon(build, true, invert);
	emit.Free(build);
	patchspots_no.Push(build->Emit(OP_JMP, 0));
}

//==========================================================================
//
//
//
//==========================================================================

FxBitOp::FxBitOp(int o, FxExpression *l, FxExpression *r)
: FxBinary(o, l, r)
{
	ValueType = TypeSInt32;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxBitOp::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();

	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	if (!left || !right)
	{
		delete this;
		return nullptr;
	}

	if (left->ValueType == TypeBool && right->ValueType == TypeBool)
	{
		ValueType = TypeBool;
	}
	else if (left->IsNumeric() && right->IsNumeric())
	{
		if (!Promote(ctx, true)) return nullptr;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Incompatible operands for bit operation");
		delete this;
		return nullptr;
	}

	if (left->isConstant() && right->isConstant())
	{
		int v1 = static_cast<FxConstant *>(left)->GetValue().GetInt();
		int v2 = static_cast<FxConstant *>(right)->GetValue().GetInt();

		FxExpression *e = new FxConstant(
			Operator == '&'? v1 & v2 : 
			Operator == '|'? v1 | v2 : 
			Operator == '^'? v1 ^ v2 : 0, ScriptPosition);

		delete this;
		return e;
	}
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxBitOp::Emit(VMFunctionBuilder *build)
{
	assert(left->ValueType->GetRegType() == REGT_INT);
	assert(right->ValueType->GetRegType() == REGT_INT);
	int instr, rop;
	ExpEmit op1, op2;

	op1 = left->Emit(build);
	op2 = right->Emit(build);
	if (op1.Konst)
	{
		swapvalues(op1, op2);
	}
	assert(!op1.Konst);
	rop = op2.RegNum;
	op2.Free(build);
	op1.Free(build);

	instr = Operator == '&' ? OP_AND_RR :
			Operator == '|' ? OP_OR_RR :
			Operator == '^' ? OP_XOR_RR : -1;

	assert(instr > 0);
	ExpEmit to(build, REGT_INT);
	build->Emit(instr + op2.Konst, to.RegNum, op1.RegNum, rop);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxShift::FxShift(int o, FxExpression *l, FxExpression *r)
	: FxBinary(o, l, r)
{
	ValueType = TypeSInt32;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxShift::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	if (!left || !right)
	{
		delete this;
		return nullptr;
	}

	if (left->IsNumeric() && right->IsNumeric())
	{
		if (!Promote(ctx, true)) return nullptr;
		if ((left->ValueType == TypeUInt32 && ctx.Version >= MakeVersion(3, 7)) && Operator == TK_RShift) Operator = TK_URShift;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Incompatible operands for shift operation");
		delete this;
		return nullptr;
	}

	if (left->isConstant() && right->isConstant())
	{
		int v1 = static_cast<FxConstant *>(left)->GetValue().GetInt();
		int v2 = static_cast<FxConstant *>(right)->GetValue().GetInt();

		FxExpression *e = new FxConstant(
			Operator == TK_LShift ? v1 << v2 :
			Operator == TK_RShift ? v1 >> v2 :
			Operator == TK_URShift ? int((unsigned int)(v1) >> v2) : 0, ScriptPosition);

		delete this;
		return e;
	}
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxShift::Emit(VMFunctionBuilder *build)
{
	assert(left->ValueType->GetRegType() == REGT_INT);
	assert(right->ValueType->GetRegType() == REGT_INT);
	static const VM_UBYTE InstrMap[][4] =
	{
		{ OP_SLL_RR, OP_SLL_KR, OP_SLL_RI },	// TK_LShift
		{ OP_SRA_RR, OP_SRA_KR, OP_SRA_RI },	// TK_RShift
		{ OP_SRL_RR, OP_SRL_KR, OP_SRL_RI },	// TK_URShift
	};
	int index, instr, rop;
	ExpEmit op1, op2;

	index = Operator == TK_LShift ? 0 :
			Operator == TK_RShift ? 1 :
			Operator == TK_URShift ? 2 : -1;
	assert(index >= 0);
	op1 = left->Emit(build);

	// Shift instructions use right-hand immediates instead of constant registers.
	if (right->isConstant())
	{
		rop = static_cast<FxConstant *>(right)->GetValue().GetInt();
		op2.Konst = true;
	}
	else
	{
		op2 = right->Emit(build);
		assert(!op2.Konst);
		op2.Free(build);
		rop = op2.RegNum;
	}

	if (!op1.Konst)
	{
		op1.Free(build);
		instr = InstrMap[index][op2.Konst? 2:0];
	}
	else
	{
		assert(!op2.Konst);
		instr = InstrMap[index][1];
	}
	assert(instr != 0);
	ExpEmit to(build, REGT_INT);
	build->Emit(instr, to.RegNum, op1.RegNum, rop);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxLtGtEq::FxLtGtEq(FxExpression *l, FxExpression *r)
	: FxBinary(TK_LtGtEq, l, r)
{
	ValueType = TypeSInt32;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxLtGtEq::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();

	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	if (!left || !right)
	{
		delete this;
		return nullptr;
	}

	if (left->IsNumeric() && right->IsNumeric())
	{
		Promote(ctx);
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "<>= expects two numeric operands");
		delete this;
		return nullptr;
	}

	if (left->isConstant() && right->isConstant())
	{
		// let's cut this short and always compare doubles. For integers the result will be exactly the same as with an integer comparison, either signed or unsigned.
		auto v1 = static_cast<FxConstant *>(left)->GetValue().GetFloat();
		auto v2 = static_cast<FxConstant *>(right)->GetValue().GetFloat();
		auto e = new FxConstant(v1 < v2 ? -1 : v1 > v2 ? 1 : 0, ScriptPosition);
		delete this;
		return e;
	}
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxLtGtEq::Emit(VMFunctionBuilder *build)
{
	ExpEmit op1 = left->Emit(build);
	ExpEmit op2 = right->Emit(build);

	assert(op1.RegType == op2.RegType);
	assert(op1.RegType == REGT_INT || op1.RegType == REGT_FLOAT);
	assert(!op1.Konst || !op2.Konst);

	ExpEmit to(build, REGT_INT);

	int instr = op1.RegType == REGT_INT ? (left->ValueType == TypeUInt32? OP_LTU_RR : OP_LT_RR) : OP_LTF_RR;
	if (op1.Konst) instr += 2;
	if (op2.Konst) instr++;


	build->Emit(OP_LI, to.RegNum, 1);										// default to 1
	build->Emit(instr, 0, op1.RegNum, op2.RegNum);							// if (left < right)
	auto j1 = build->Emit(OP_JMP, 1);
	build->Emit(OP_LI, to.RegNum, -1);										// result is -1
	auto j2 = build->Emit(OP_JMP, 1);										// jump to end
	build->BackpatchToHere(j1);
	build->Emit(instr + OP_LE_RR - OP_LT_RR, 0, op1.RegNum, op2.RegNum);	// if (left == right)
	auto j3 = build->Emit(OP_JMP, 1);
	build->Emit(OP_LI, to.RegNum, 0);										// result is 0
	build->BackpatchToHere(j2);
	build->BackpatchToHere(j3);

	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxConcat::FxConcat(FxExpression *l, FxExpression *r)
	: FxBinary(TK_DotDot, l, r)
{
	ValueType = TypeString;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxConcat::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();

	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	if (!left || !right)
	{
		delete this;
		return nullptr;
	}

	// To concatenate two operands the only requirement is that they are integral types, i.e. can occupy a register
	if (left->ValueType->GetRegType() == REGT_NIL || right->ValueType->GetRegType() == REGT_NIL)
	{
		ScriptPosition.Message(MSG_ERROR, "Invalid operand for string concatenation");
		delete this;
		return nullptr;
	}

	if (left->isConstant() && right->isConstant() && (left->ValueType == TypeString || left->ValueType == TypeName) && (right->ValueType == TypeString || right->ValueType == TypeName))
	{
		// for now this is only types which have a constant string representation.
		auto v1 = static_cast<FxConstant *>(left)->GetValue().GetString();
		auto v2 = static_cast<FxConstant *>(right)->GetValue().GetString();
		auto e = new FxConstant(v1 + v2, ScriptPosition);
		delete this;
		return e;
	}
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxConcat::Emit(VMFunctionBuilder *build)
{
	ExpEmit op1 = left->Emit(build);
	ExpEmit op2 = right->Emit(build);
	ExpEmit strng, strng2;

	if (op1.RegType == REGT_STRING && op1.Konst)
	{
		strng = ExpEmit(build, REGT_STRING);
		build->Emit(OP_LKS, strng.RegNum, op1.RegNum);
	}
	else if (op1.RegType == REGT_STRING)
	{
		strng = op1;
	}
	else
	{
		int cast = 0;
		strng = ExpEmit(build, REGT_STRING);
		if (op1.Konst)
		{
			ExpEmit nonconst(build, op1.RegType);
			build->Emit(op1.RegType == REGT_INT ? OP_LK : op1.RegType == REGT_FLOAT ? OP_LKF : OP_LKP, nonconst.RegNum, op1.RegNum);
			op1 = nonconst;
		}
		if (op1.RegType == REGT_FLOAT) cast = op1.RegCount == 1 ? CAST_F2S : op1.RegCount == 2 ? CAST_V22S : CAST_V32S;
		else if (left->ValueType == TypeUInt32) cast = CAST_U2S;
		else if (left->ValueType == TypeName) cast = CAST_N2S;
		else if (left->ValueType == TypeSound) cast = CAST_So2S;
		else if (left->ValueType == TypeColor) cast = CAST_Co2S;
		else if (left->ValueType == TypeSpriteID) cast = CAST_SID2S;
		else if (left->ValueType == TypeTextureID) cast = CAST_TID2S;
		else if (op1.RegType == REGT_POINTER) cast = CAST_P2S;
		else if (op1.RegType == REGT_INT) cast = CAST_I2S;
		else assert(false && "Bad type for string concatenation");
		build->Emit(OP_CAST, strng.RegNum, op1.RegNum, cast);
		op1.Free(build);
	}

	if (op2.RegType == REGT_STRING && op2.Konst)
	{
		strng2 = ExpEmit(build, REGT_STRING);
		build->Emit(OP_LKS, strng2.RegNum, op2.RegNum);
	}
	else if (op2.RegType == REGT_STRING)
	{
		strng2 = op2;
	}
	else
	{
		int cast = 0;
		strng2 = ExpEmit(build, REGT_STRING);
		if (op2.Konst)
		{
			ExpEmit nonconst(build, op2.RegType);
			build->Emit(op2.RegType == REGT_INT ? OP_LK : op2.RegType == REGT_FLOAT ? OP_LKF : OP_LKP, nonconst.RegNum, op2.RegNum);
			op2 = nonconst;
		}
		if (op2.RegType == REGT_FLOAT) cast = op2.RegCount == 1 ? CAST_F2S : op2.RegCount == 2 ? CAST_V22S : CAST_V32S;
		else if (right->ValueType == TypeUInt32) cast = CAST_U2S;
		else if (right->ValueType == TypeName) cast = CAST_N2S;
		else if (right->ValueType == TypeSound) cast = CAST_So2S;
		else if (right->ValueType == TypeColor) cast = CAST_Co2S;
		else if (right->ValueType == TypeSpriteID) cast = CAST_SID2S;
		else if (right->ValueType == TypeTextureID) cast = CAST_TID2S;
		else if (op2.RegType == REGT_POINTER) cast = CAST_P2S;
		else if (op2.RegType == REGT_INT) cast = CAST_I2S;
		else assert(false && "Bad type for string concatenation");
		build->Emit(OP_CAST, strng2.RegNum, op2.RegNum, cast);
		op2.Free(build);
	}
	strng.Free(build);
	strng2.Free(build);
	ExpEmit dest(build, REGT_STRING);
	assert(strng.RegType == strng2.RegType && strng.RegType == REGT_STRING);
	build->Emit(OP_CONCAT, dest.RegNum, strng.RegNum, strng2.RegNum);
	return dest;
}

//==========================================================================
//
//
//
//==========================================================================

FxBinaryLogical::FxBinaryLogical(int o, FxExpression *l, FxExpression *r)
: FxExpression(EFX_BinaryLogical, l->ScriptPosition)
{
	Operator=o;
	left=l;
	right=r;
	ValueType = TypeBool;
}

//==========================================================================
//
//
//
//==========================================================================

FxBinaryLogical::~FxBinaryLogical()
{
	SAFE_DELETE(left);
	SAFE_DELETE(right);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxBinaryLogical::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	ABORT(right && left);

	if (left->ValueType != TypeBool)
	{
		left = new FxBoolCast(left);
		SAFE_RESOLVE(left, ctx);
	}
	if (right->ValueType != TypeBool)
	{
		right = new FxBoolCast(right);
		SAFE_RESOLVE(right, ctx);
	}

	int b_left=-1, b_right=-1;
	if (left->isConstant()) b_left = static_cast<FxConstant *>(left)->GetValue().GetBool();
	if (right->isConstant()) b_right = static_cast<FxConstant *>(right)->GetValue().GetBool();

	// Do some optimizations. This will throw out all sub-expressions that are not
	// needed to retrieve the final result.
	if (Operator == TK_AndAnd)
	{
		if (b_left==0 || b_right==0)
		{
			FxExpression *x = new FxConstant(true, ScriptPosition);
			delete this;
			return x;
		}
		else if (b_left==1 && b_right==1)
		{
			FxExpression *x = new FxConstant(false, ScriptPosition);
			delete this;
			return x;
		}
		else if (b_left==1)
		{
			FxExpression *x = right;
			right=nullptr;
			delete this;
			return x;
		}
		else if (b_right==1)
		{
			FxExpression *x = left;
			left=nullptr;
			delete this;
			return x;
		}
	}
	else if (Operator == TK_OrOr)
	{
		if (b_left==1 || b_right==1)
		{
			FxExpression *x = new FxConstant(true, ScriptPosition);
			delete this;
			return x;
		}
		if (b_left==0 && b_right==0)
		{
			FxExpression *x = new FxConstant(false, ScriptPosition);
			delete this;
			return x;
		}
		else if (b_left==0)
		{
			FxExpression *x = right;
			right=nullptr;
			delete this;
			return x;
		}
		else if (b_right==0)
		{
			FxExpression *x = left;
			left=nullptr;
			delete this;
			return x;
		}
	}
	Flatten();
	return this;
}

//==========================================================================
//
// flatten a list of the same operator into a single node.
//
//==========================================================================

void FxBinaryLogical::Flatten()
{
	if (left->ExprType == EFX_BinaryLogical && static_cast<FxBinaryLogical *>(left)->Operator == Operator)
	{
		list = std::move(static_cast<FxBinaryLogical *>(left)->list);
		delete left;
	}
	else
	{
		list.Push(left);
	}

	if (right->ExprType == EFX_BinaryLogical && static_cast<FxBinaryLogical *>(right)->Operator == Operator)
	{
		auto &rlist = static_cast<FxBinaryLogical *>(right)->list;
		auto cnt = rlist.Size();
		auto v = list.Reserve(cnt);
		for (unsigned i = 0; i < cnt; i++)
		{
			list[v + i] = rlist[i];
			rlist[i] = nullptr;
		}
		delete right;
	}
	else
	{
		list.Push(right);
	}
	left = right = nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxBinaryLogical::Emit(VMFunctionBuilder *build)
{
	TArray<size_t> yes, no;
	bool invert = Operator == TK_OrOr;

	for (unsigned i = 0; i < list.Size(); i++)
	{
		list[i]->EmitCompare(build, invert, yes, no);
	}
	build->BackpatchListToHere(yes);
	ExpEmit to(build, REGT_INT);
	build->Emit(OP_LI, to.RegNum, (Operator == TK_AndAnd) ? 1 : 0);
	build->Emit(OP_JMP, 1);
	build->BackpatchListToHere(no);
	auto ctarget = build->Emit(OP_LI, to.RegNum, (Operator == TK_AndAnd) ? 0 : 1);
	list.DeleteAndClear();
	list.ShrinkToFit();
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxDotCross::FxDotCross(int o, FxExpression *l, FxExpression *r)
	: FxExpression(EFX_DotCross, l->ScriptPosition)
{
	Operator = o;
	left = l;
	right = r;
}

//==========================================================================
//
//
//
//==========================================================================

FxDotCross::~FxDotCross()
{
	SAFE_DELETE(left);
	SAFE_DELETE(right);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxDotCross::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	ABORT(right && left);

	if (!left->IsVector() || left->ValueType != right->ValueType || (Operator == TK_Cross && left->ValueType != TypeVector3))
	{
		ScriptPosition.Message(MSG_ERROR, "Incompatible operants for %sproduct", Operator == TK_Cross ? "cross-" : "dot-");
		delete this;
		return nullptr;
	}
	ValueType = Operator == TK_Cross ? (PType*)TypeVector3 : TypeFloat64;
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxDotCross::Emit(VMFunctionBuilder *build)
{
	ExpEmit to(build, ValueType->GetRegType(), ValueType->GetRegCount());
	ExpEmit op1 = left->Emit(build);
	ExpEmit op2 = right->Emit(build);
	int op = Operator == TK_Cross ? OP_CROSSV_RR : left->ValueType == TypeVector3 ? OP_DOTV3_RR : OP_DOTV2_RR;
	build->Emit(op, to.RegNum, op1.RegNum, op2.RegNum);
	op1.Free(build);
	op2.Free(build);
	return to;
}

//==========================================================================
//
//
//
//==========================================================================

FxTypeCheck::FxTypeCheck(FxExpression *l, FxExpression *r)
	: FxExpression(EFX_TypeCheck, l->ScriptPosition)
{
	left = l;
	right = r;
	ValueType = TypeBool;
}

//==========================================================================
//
//
//
//==========================================================================

FxTypeCheck::~FxTypeCheck()
{
	SAFE_DELETE(left);
	SAFE_DELETE(right);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxTypeCheck::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	// This must resolve the cast separately so that it can set the proper type for class descriptors.
	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	ABORT(right && left);

	if (left->ValueType->isClassPointer())
	{
		left = new FxClassTypeCast(NewClassPointer(RUNTIME_CLASS(DObject)), left, false);
		ClassCheck = true;
	}
	else
	{
		left = new FxTypeCast(left, NewPointer(RUNTIME_CLASS(DObject)), false);
		ClassCheck = false;
	}
	right = new FxClassTypeCast(NewClassPointer(RUNTIME_CLASS(DObject)), right, false);

	RESOLVE(left, ctx);
	RESOLVE(right, ctx);
	ABORT(right && left);

	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxTypeCheck::EmitCommon(VMFunctionBuilder *build)
{
	ExpEmit castee = left->Emit(build);
	ExpEmit casttype = right->Emit(build);
	castee.Free(build);
	casttype.Free(build);
	ExpEmit ares(build, REGT_POINTER);
	if (!ClassCheck) build->Emit(casttype.Konst ? OP_DYNCAST_K : OP_DYNCAST_R, ares.RegNum, castee.RegNum, casttype.RegNum);
	else build->Emit(casttype.Konst ? OP_DYNCASTC_K : OP_DYNCASTC_R, ares.RegNum, castee.RegNum, casttype.RegNum);
	return ares;
}

ExpEmit FxTypeCheck::Emit(VMFunctionBuilder *build)
{
	ExpEmit ares = EmitCommon(build);
	ares.Free(build);
	ExpEmit bres(build, REGT_INT);
	build->Emit(OP_CASTB, bres.RegNum, ares.RegNum, CASTB_A);
	return bres;
}

void FxTypeCheck::EmitCompare(VMFunctionBuilder *build, bool invert, TArray<size_t> &patchspots_yes, TArray<size_t> &patchspots_no)
{
	ExpEmit ares = EmitCommon(build);
	ares.Free(build);
	build->Emit(OP_EQA_K, !invert, ares.RegNum, build->GetConstantAddress(nullptr));
	patchspots_no.Push(build->Emit(OP_JMP, 0));
}

//==========================================================================
//
//
//
//==========================================================================

FxDynamicCast::FxDynamicCast(PClass * cls, FxExpression *r)
	: FxExpression(EFX_DynamicCast, r->ScriptPosition)
{
	expr = r;
	CastType = cls;
}

//==========================================================================
//
//
//
//==========================================================================

FxDynamicCast::~FxDynamicCast()
{
	SAFE_DELETE(expr);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxDynamicCast::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(expr, ctx);
	bool constflag = expr->ValueType->isPointer() && expr->ValueType->toPointer()->IsConst;	
	expr = new FxTypeCast(expr, NewPointer(RUNTIME_CLASS(DObject), constflag), true, true);
	expr = expr->Resolve(ctx);
	if (expr == nullptr)
	{
		delete this;
		return nullptr;
	}
	ValueType = NewPointer(CastType, constflag);
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxDynamicCast::Emit(VMFunctionBuilder *build)
{
	ExpEmit castee = expr->Emit(build);
	castee.Free(build);
	ExpEmit ares(build, REGT_POINTER);
	build->Emit(OP_DYNCAST_K, ares.RegNum, castee.RegNum, build->GetConstantAddress(CastType));
	return ares;
}

//==========================================================================
//
//
//
//==========================================================================

FxConditional::FxConditional(FxExpression *c, FxExpression *t, FxExpression *f)
: FxExpression(EFX_Conditional, c->ScriptPosition)
{
	condition = c;
	truex=t;
	falsex=f;
}

//==========================================================================
//
//
//
//==========================================================================

FxConditional::~FxConditional()
{
	SAFE_DELETE(condition);
	SAFE_DELETE(truex);
	SAFE_DELETE(falsex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxConditional::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	RESOLVE(condition, ctx);
	RESOLVE(truex, ctx);
	RESOLVE(falsex, ctx);
	ABORT(condition && truex && falsex);

	if (truex->ValueType == falsex->ValueType)
		ValueType = truex->ValueType;
	else if (truex->ValueType == TypeBool && falsex->ValueType == TypeBool)
		ValueType = TypeBool;
	else if (truex->IsInteger() && falsex->IsInteger())
		ValueType = TypeSInt32;
	else if (truex->IsNumeric() && falsex->IsNumeric())
		ValueType = TypeFloat64;
	else if (truex->IsPointer() && falsex->ValueType == TypeNullPtr)
		ValueType = truex->ValueType;
	else if (falsex->IsPointer() && truex->ValueType == TypeNullPtr)
		ValueType = falsex->ValueType;
	else
		ValueType = TypeVoid;
	//else if (truex->ValueType != falsex->ValueType)

	if (ValueType->GetRegType() == REGT_NIL)
	{
		ScriptPosition.Message(MSG_ERROR, "Incompatible types for ?: operator");
		delete this;
		return nullptr;
	}

	if (condition->ValueType != TypeBool)
	{
		condition = new FxBoolCast(condition);
		SAFE_RESOLVE(condition, ctx);
	}

	if (condition->isConstant())
	{
		ExpVal condval = static_cast<FxConstant *>(condition)->GetValue();
		bool result = condval.GetBool();

		FxExpression *e = result? truex:falsex;
		delete (result? falsex:truex);
		falsex = truex = nullptr;
		delete this;
		return e;
	}

	if (IsFloat())
	{
		if (truex->ValueType->GetRegType() != REGT_FLOAT)
		{
			truex = new FxFloatCast(truex);
			RESOLVE(truex, ctx);
		}
		if (falsex->ValueType->GetRegType() != REGT_FLOAT)
		{
			falsex = new FxFloatCast(falsex);
			RESOLVE(falsex, ctx);
		}
	}

	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxConditional::Emit(VMFunctionBuilder *build)
{
	size_t truejump;
	ExpEmit out, falseout;

	// The true and false expressions ought to be assigned to the
	// same temporary instead of being copied to it. Oh well; good enough
	// for now.
	TArray<size_t> yes, no;
	condition->EmitCompare(build, false, yes, no);

	build->BackpatchListToHere(yes);

	if (truex->isConstant() && truex->ValueType->GetRegType() == REGT_INT)
	{
		out = ExpEmit(build, REGT_INT);
		build->EmitLoadInt(out.RegNum, static_cast<FxConstant *>(truex)->GetValue().GetInt());
	}
	else
	{
		ExpEmit trueop = truex->Emit(build);
		if (trueop.Konst)
		{
			trueop.Free(build);
			if (trueop.RegType == REGT_FLOAT)
			{
				out = ExpEmit(build, REGT_FLOAT);
				build->Emit(OP_LKF, out.RegNum, trueop.RegNum);
			}
			else if (trueop.RegType == REGT_POINTER)
			{
				out = ExpEmit(build, REGT_POINTER);
				build->Emit(OP_LKP, out.RegNum, trueop.RegNum);
			}
			else
			{
				assert(trueop.RegType == REGT_STRING);
				out = ExpEmit(build, REGT_STRING);
				build->Emit(OP_LKS, out.RegNum, trueop.RegNum);
			}
		}
		else
		{
			// Use the register returned by the true condition as the
			// target for the false condition, if temporary.
			// If this is a local variable we need another register for the result.
			if (trueop.Fixed)
			{
				out = ExpEmit(build, trueop.RegType, trueop.RegCount);
				build->Emit(truex->ValueType->GetMoveOp(), out.RegNum, trueop.RegNum, 0);
			}
			else out = trueop;
		}
	}
	// Make sure to skip the false path.
	truejump = build->Emit(OP_JMP, 0);

	// Evaluate false expression.
	build->BackpatchListToHere(no);
	if (falsex->isConstant() && falsex->ValueType->GetRegType() == REGT_INT)
	{
		build->EmitLoadInt(out.RegNum, static_cast<FxConstant *>(falsex)->GetValue().GetInt());
	}
	else
	{
		ExpEmit falseop = falsex->Emit(build);
		if (falseop.Konst)
		{
			if (falseop.RegType == REGT_FLOAT)
			{
				build->Emit(OP_LKF, out.RegNum, falseop.RegNum);
			}
			else if (falseop.RegType == REGT_POINTER)
			{
				build->Emit(OP_LKP, out.RegNum, falseop.RegNum);
			}
			else
			{
				assert(falseop.RegType == REGT_STRING);
				build->Emit(OP_LKS, out.RegNum, falseop.RegNum);
			}
			falseop.Free(build);
		}
		else
		{
			// Move result from the register returned by "false" to the one
			// returned by "true" so that only one register is returned by
			// this tree.
			falseop.Free(build);
			build->Emit(falsex->ValueType->GetMoveOp(), out.RegNum, falseop.RegNum, 0);
		}
	}
	build->BackpatchToHere(truejump);

	return out;
}

//==========================================================================
//
//
//
//==========================================================================
FxAbs::FxAbs(FxExpression *v)
: FxExpression(EFX_Abs, v->ScriptPosition)
{
	val = v;
	ValueType = v->ValueType;
}

//==========================================================================
//
//
//
//==========================================================================

FxAbs::~FxAbs()
{
	SAFE_DELETE(val);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxAbs::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(val, ctx);

	if (val->ValueType == TypeBool)	// abs of a boolean is always the same as the operand
	{
		auto v = val;
		val = nullptr;
		delete this;
		return v;
	}
	if (!val->IsNumeric())
	{
		ScriptPosition.Message(MSG_ERROR, "Numeric type expected");
		delete this;
		return nullptr;
	}
	else if (val->isConstant())
	{
		ExpVal value = static_cast<FxConstant *>(val)->GetValue();
		switch (value.Type->GetRegType())
		{
		case REGT_INT:
			value.Int = abs(value.Int);
			break;

		case REGT_FLOAT:
			value.Float = fabs(value.Float);
			break;

		default:
			// shouldn't happen
			delete this;
			return nullptr;
		}
		FxExpression *x = new FxConstant(value, ScriptPosition);
		delete this;
		return x;
	}
	ValueType = val->ValueType;
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxAbs::Emit(VMFunctionBuilder *build)
{
	assert(ValueType == val->ValueType);
	ExpEmit from = val->Emit(build);
	ExpEmit to;
	assert(from.Konst == 0);
	assert(ValueType->GetRegCount() == 1);
	// Do it in-place, unless a local variable
	if (from.Fixed)
	{
		to = ExpEmit(build, from.RegType);
		from.Free(build);
	}
	else
	{
		to = from;
	}

	if (ValueType->GetRegType() == REGT_INT)
	{
		build->Emit(OP_ABS, to.RegNum, from.RegNum, 0);
	}
	else
	{
		build->Emit(OP_FLOP, to.RegNum, from.RegNum, FLOP_ABS);
	}
	return to;
}

//==========================================================================
//
//
//
//==========================================================================
FxATan2::FxATan2(FxExpression *y, FxExpression *x, const FScriptPosition &pos)
: FxExpression(EFX_ATan2, pos)
{
	yval = y;
	xval = x;
}

//==========================================================================
//
//
//
//==========================================================================
FxATan2::~FxATan2()
{
	SAFE_DELETE(yval);
	SAFE_DELETE(xval);
}

//==========================================================================
//
//
//
//==========================================================================
FxExpression *FxATan2::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(yval, ctx);
	SAFE_RESOLVE(xval, ctx);

	if (!yval->IsNumeric() || !xval->IsNumeric())
	{
		ScriptPosition.Message(MSG_ERROR, "numeric value expected for parameter");
		delete this;
		return nullptr;
	}
	if (yval->isConstant() && xval->isConstant())
	{
		double y = static_cast<FxConstant *>(yval)->GetValue().GetFloat();
		double x = static_cast<FxConstant *>(xval)->GetValue().GetFloat();
		FxExpression *z = new FxConstant(g_atan2(y, x) * (180 / M_PI), ScriptPosition);
		delete this;
		return z;
	}
	if (yval->ValueType->GetRegType() != REGT_FLOAT && !yval->isConstant())
	{
		yval = new FxFloatCast(yval);
	}
	if (xval->ValueType->GetRegType() != REGT_FLOAT && !xval->isConstant())
	{
		xval = new FxFloatCast(xval);
	}
	ValueType = TypeFloat64;
	return this;
}

//==========================================================================
//
//
//
//==========================================================================
ExpEmit FxATan2::Emit(VMFunctionBuilder *build)
{
	ExpEmit yreg = ToReg(build, yval);
	ExpEmit xreg = ToReg(build, xval);
	yreg.Free(build);
	xreg.Free(build);
	ExpEmit out(build, REGT_FLOAT);
	build->Emit(OP_ATAN2, out.RegNum, yreg.RegNum, xreg.RegNum);
	return out;
}

//==========================================================================
//
//
//
//==========================================================================
FxNew::FxNew(FxExpression *v)
	: FxExpression(EFX_New, v->ScriptPosition)
{
	val = new FxClassTypeCast(NewClassPointer(RUNTIME_CLASS(DObject)), v, false);
	ValueType = NewPointer(RUNTIME_CLASS(DObject));
	CallingFunction = nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

FxNew::~FxNew()
{
	SAFE_DELETE(val);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxNew::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(val, ctx);

	CallingFunction = ctx.Function;
	if (!val->ValueType->isClassPointer())
	{
		ScriptPosition.Message(MSG_ERROR, "Class type expected");
		delete this;
		return nullptr;
	}
	if (val->isConstant())
	{
		auto cls = static_cast<PClass *>(static_cast<FxConstant*>(val)->GetValue().GetPointer());
		if (cls->bAbstract)
		{
			ScriptPosition.Message(MSG_ERROR, "Cannot instantiate abstract class %s", cls->TypeName.GetChars());
			delete this;
			return nullptr;
		}

		//
		int outerside = ctx.Function && ctx.Function->Variants.Size() ? FScopeBarrier::SideFromFlags(ctx.Function->Variants[0].Flags) : FScopeBarrier::Side_Virtual;
		if (outerside == FScopeBarrier::Side_Virtual)
			outerside = FScopeBarrier::SideFromObjectFlags(ctx.Class->ScopeFlags);
		int innerside = FScopeBarrier::SideFromObjectFlags(cls->VMType->ScopeFlags);
		if ((outerside != innerside) && (innerside != FScopeBarrier::Side_PlainData)) // "cannot construct ui class ... from data context"
		{
			ScriptPosition.Message(MSG_ERROR, "Cannot construct %s class %s from %s context", FScopeBarrier::StringFromSide(innerside), cls->TypeName.GetChars(), FScopeBarrier::StringFromSide(outerside));
			delete this;
			return nullptr;
		}

		ValueType = NewPointer(cls);
	}

	return this;
}

//==========================================================================
//
// The CVAR is for finding places where thinkers are created.
// Those will require code changes in ZScript 4.0.
//
//==========================================================================
CVAR(Bool, vm_warnthinkercreation, false, 0)

static DObject *BuiltinNew(PClass *cls, int outerside, int backwardscompatible)
{
	if (cls == nullptr)
	{
		ThrowAbortException(X_OTHER, "New without a class");
		return nullptr;
	}
	if (cls->ConstructNative == nullptr)
	{
		ThrowAbortException(X_OTHER, "Class %s requires native construction", cls->TypeName.GetChars());
		return nullptr;
	}
	if (cls->bAbstract)
	{
		ThrowAbortException(X_OTHER, "Cannot instantiate abstract class %s", cls->TypeName.GetChars());
		return nullptr;
	}
	// Creating actors here must be outright prohibited,
	if (cls->IsDescendantOf(NAME_Actor))
	{
		ThrowAbortException(X_OTHER, "Cannot create actors with 'new'");
		return nullptr;
	}
	if ((vm_warnthinkercreation || !backwardscompatible) && cls->IsDescendantOf(NAME_Thinker))
	{
		// This must output a diagnostic warning
		Printf("Using 'new' to create thinkers is deprecated.");
	}
	// [ZZ] validate readonly and between scope construction
	if (outerside) FScopeBarrier::ValidateNew(cls, outerside - 1);
	DObject *object;
	if (!cls->IsDescendantOf(NAME_Thinker))
	{
		object = cls->CreateNew();
	}
	else
	{
		object = currentVMLevel->CreateThinker(cls);
	}
	return object;
}

DEFINE_ACTION_FUNCTION_NATIVE(DObject, BuiltinNew, BuiltinNew)
{
	PARAM_PROLOGUE;
	PARAM_CLASS(cls, DObject);
	PARAM_INT(outerside);
	PARAM_INT(compatible);
	ACTION_RETURN_OBJECT(BuiltinNew(cls, outerside, compatible));
}

ExpEmit FxNew::Emit(VMFunctionBuilder *build)
{
	ExpEmit to(build, REGT_POINTER);

	// Call DecoRandom to generate a random number.
	VMFunction *callfunc;
	auto sym = FindBuiltinFunction(NAME_BuiltinNew);
	
	assert(sym);
	callfunc = sym->Variants[0].Implementation;
	
	FunctionCallEmitter emitters(callfunc);

	int outerside = -1;
	if (!val->isConstant())
	{
		int outerside = FScopeBarrier::SideFromFlags(CallingFunction->Variants[0].Flags);
		if (outerside == FScopeBarrier::Side_Virtual)
			outerside = FScopeBarrier::SideFromObjectFlags(CallingFunction->OwningClass->ScopeFlags);
	}
	emitters.AddParameter(build, val);
	emitters.AddParameterIntConst(outerside + 1);
	emitters.AddParameterIntConst(1);	// Todo: 1 only if version < 4.0.0
	emitters.AddReturn(REGT_POINTER);
	return emitters.EmitCall(build);
}

//==========================================================================
//
// The atan2 opcode only takes registers as parameters, so any constants
// must be loaded into registers first.
//
//==========================================================================
ExpEmit FxATan2::ToReg(VMFunctionBuilder *build, FxExpression *val)
{
	if (val->isConstant())
	{
		ExpEmit reg(build, REGT_FLOAT);
		build->Emit(OP_LKF, reg.RegNum, build->GetConstantFloat(static_cast<FxConstant*>(val)->GetValue().GetFloat()));
		return reg;
	}
	return val->Emit(build);
}

//==========================================================================
//
//
//
//==========================================================================
FxMinMax::FxMinMax(TArray<FxExpression*> &expr, FName type, const FScriptPosition &pos)
: FxExpression(EFX_MinMax, pos), Type(type)
{
	assert(expr.Size() > 0);
	assert(type == NAME_Min || type == NAME_Max);

	choices.Resize(expr.Size());
	for (unsigned i = 0; i < expr.Size(); ++i)
	{
		choices[i] = expr[i];
		expr[i] = nullptr;
	}
}

//==========================================================================
//
//
//
//==========================================================================
FxExpression *FxMinMax::Resolve(FCompileContext &ctx)
{
	unsigned int i;
	int intcount, floatcount, uintcount;

	CHECKRESOLVED();

	// Determine if float or int
	uintcount = intcount = floatcount = 0;

	for (i = 0; i < choices.Size(); ++i)
	{
		RESOLVE(choices[i], ctx);
		ABORT(choices[i]);

		if (choices[i]->IsFloat())
		{
			floatcount++;
		}
		else if (choices[i]->IsInteger())
		{
			intcount++;
			auto type = choices[i]->ValueType;
			if (type == TypeUInt32 || type == TypeUInt16 || type == TypeUInt8 || type == TypeBool) uintcount++;
			else if (choices[i]->isConstant() && static_cast<FxConstant*>(choices[i])->GetValue().GetInt() > 0) uintcount++;
		}
		else
		{
			ScriptPosition.Message(MSG_ERROR, "Arguments must be of type int or float");
			delete this;
			return nullptr;
		}
	}
	if (floatcount != 0)
	{
		ValueType = TypeFloat64;
		if (intcount != 0)
		{ // There are some ints that need to be cast to floats
			for (i = 0; i < choices.Size(); ++i)
			{
				if (choices[i]->ValueType->GetRegType() == REGT_INT)
				{
					choices[i] = new FxFloatCast(choices[i]);
					RESOLVE(choices[i], ctx);
					ABORT(choices[i]);
				}
			}
		}
	}
	else
	{
		ValueType = uintcount == intcount? TypeUInt32 : TypeSInt32;
	}

	// If at least two arguments are constants, they can be solved now.

	// Look for first constant
	for (i = 0; i < choices.Size(); ++i)
	{
		if (choices[i]->isConstant())
		{
			ExpVal best = static_cast<FxConstant *>(choices[i])->GetValue();
			// Compare against remaining constants, which are removed.
			// The best value gets stored in this one.
			for (unsigned j = i + 1; j < choices.Size(); )
			{
				if (!choices[j]->isConstant())
				{
					j++;
				}
				else
				{
					ExpVal value = static_cast<FxConstant *>(choices[j])->GetValue();
					assert(value.Type == ValueType);
					if (Type == NAME_Min)
					{
						if (value.Type->GetRegType() == REGT_FLOAT)
						{
							if (value.Float < best.Float)
							{
								best.Float = value.Float;
							}
						}
						else
						{
							if (value.Int < best.Int)
							{
								best.Int = value.Int;
							}
						}
					}
					else
					{
						if (value.Type->GetRegType() == REGT_FLOAT)
						{
							if (value.Float > best.Float)
							{
								best.Float = value.Float;
							}
						}
						else
						{
							if (value.Int > best.Int)
							{
								best.Int = value.Int;
							}
						}
					}
					delete choices[j];
					choices[j] = nullptr;
					choices.Delete(j);
				}
			}
			FxExpression *x = new FxConstant(best, ScriptPosition);
			if (i == 0 && choices.Size() == 1)
			{ // Every choice was constant
				delete this;
				return x;
			}
			delete choices[i];
			choices[i] = x;
			break;
		}
	}
	// If the first choice is constant, swap it with the second one.
	// Note that all constants have already been folded together so there can only be one constant in the list of choices.
	if (choices[0]->isConstant())
	{
		std::swap(choices[0], choices[1]);
	}
	return this;
}

//==========================================================================
//
//
//
//==========================================================================
static void EmitLoad(VMFunctionBuilder *build, const ExpEmit resultreg, const ExpVal &value)
{
	if (resultreg.RegType == REGT_FLOAT)
	{
		build->Emit(OP_LKF, resultreg.RegNum, build->GetConstantFloat(value.GetFloat()));
	}
	else
	{
		build->EmitLoadInt(resultreg.RegNum, value.GetInt());
	}
}

ExpEmit FxMinMax::Emit(VMFunctionBuilder *build)
{
	unsigned i;
	int opcode;

	assert(choices.Size() > 0);
	assert(!choices[0]->isConstant());
	static_assert(OP_MAXF_RK == OP_MAXF_RR+1, "maxf opcodes not continuous");
	static_assert(OP_MAX_RK == OP_MAX_RR+1, "max opcodes not continuous");
	static_assert(OP_MINF_RK == OP_MINF_RR+1, "minf opcodes not continuous");
	static_assert(OP_MIN_RK == OP_MIN_RR+1, "min opcodes not continuous");
	static_assert(OP_MAXU_RK == OP_MAXU_RR + 1, "maxu opcodes not continuous");
	static_assert(OP_MINU_RK == OP_MINU_RR + 1, "minu opcodes not continuous");

	if (Type == NAME_Min)
	{
		opcode = ValueType->GetRegType() == REGT_FLOAT ? OP_MINF_RR : ValueType == TypeUInt32? OP_MINU_RR : OP_MIN_RR;
	}
	else
	{
		opcode = ValueType->GetRegType() == REGT_FLOAT ? OP_MAXF_RR : ValueType == TypeUInt32 ? OP_MAXU_RR : OP_MAX_RR;
	}

	ExpEmit firstreg = choices[0]->Emit(build);
	ExpEmit destreg;

	if (firstreg.Fixed)
	{
		destreg = ExpEmit(build, firstreg.RegType);
		firstreg.Free(build);
	}
	else
	{
		destreg = firstreg;
	}


	// Compare every choice. Better matches get copied to the bestreg.
	for (i = 1; i < choices.Size(); ++i)
	{
		ExpEmit checkreg = choices[i]->Emit(build);
		assert(checkreg.RegType == firstreg.RegType);
		build->Emit(opcode + checkreg.Konst, destreg.RegNum, firstreg.RegNum, checkreg.RegNum);
		firstreg = destreg;
		checkreg.Free(build);
	}
	return destreg;
}

//==========================================================================
//
//
//
//==========================================================================
FxRandom::FxRandom(EFxType type, FRandom * r, const FScriptPosition &pos)
: FxExpression(EFX_Random, pos)
{
	rng = r;
}

//==========================================================================
//
//
//
//==========================================================================
FxRandom::FxRandom(FRandom * r, FxExpression *mi, FxExpression *ma, const FScriptPosition &pos, bool nowarn)
	: FxRandom(EFX_Random, r, pos)
{
	assert(mi && ma);
	min = new FxIntCast(mi, nowarn);
	max = new FxIntCast(ma, nowarn);
	ValueType = TypeSInt32;
}

//==========================================================================
//
//
//
//==========================================================================

FxRandom::~FxRandom()
{
	SAFE_DELETE(min);
	SAFE_DELETE(max);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxRandom::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	if (min && max)
	{
		RESOLVE(min, ctx);
		RESOLVE(max, ctx);
		ABORT(min && max);
		assert(min->ValueType == ValueType);
		assert(max->ValueType == ValueType);
	}
	return this;
};


//==========================================================================
//
//
//
//==========================================================================

static int NativeRandom(FRandom *rng, int min, int max)
{
	if (max < min)
	{
		std::swap(max, min);
	}
	return (*rng)(max - min + 1) + min;
}

DEFINE_ACTION_FUNCTION_NATIVE(DObject, BuiltinRandom, NativeRandom)
{
	PARAM_PROLOGUE;
	PARAM_POINTER(rng, FRandom);
	PARAM_INT(min);
	PARAM_INT(max);
	ACTION_RETURN_INT(NativeRandom(rng, min, max));
}

ExpEmit FxRandom::Emit(VMFunctionBuilder *build)
{
	// Call DecoRandom to generate a random number.
	VMFunction *callfunc;
	auto sym = FindBuiltinFunction(NAME_BuiltinRandom);

	assert(sym);
	callfunc = sym->Variants[0].Implementation;
	assert(min && max);

	FunctionCallEmitter emitters(callfunc);
	emitters.AddParameterPointerConst(rng);
	emitters.AddParameter(build, min);
	emitters.AddParameter(build, max);
	emitters.AddReturn(REGT_INT);
	return emitters.EmitCall(build);
}

//==========================================================================
//
//
//
//==========================================================================
FxRandomPick::FxRandomPick(FRandom *r, TArray<FxExpression*> &expr, bool floaty, const FScriptPosition &pos, bool nowarn)
: FxExpression(EFX_RandomPick, pos)
{
	assert(expr.Size() > 0);
	choices.Resize(expr.Size());
	for (unsigned int index = 0; index < expr.Size(); index++)
	{
		if (floaty)
		{
			choices[index] = new FxFloatCast(expr[index]);
			expr[index] = nullptr;
		}
		else
		{
			choices[index] = new FxIntCast(expr[index], nowarn);
			expr[index] = nullptr;
		}

	}
	rng = r;
	if (floaty)
	{
		ValueType = TypeFloat64;
	}
	else
	{
		ValueType = TypeSInt32;
	}
}

//==========================================================================
//
//
//
//==========================================================================

FxRandomPick::~FxRandomPick()
{
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxRandomPick::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	for (unsigned int index = 0; index < choices.Size(); index++)
	{
		RESOLVE(choices[index], ctx);
		ABORT(choices[index]);
		assert(choices[index]->ValueType == ValueType);
	}
	return this;
};


//==========================================================================
//
// FxPick :: Emit
//
// The expression:
//   a = pick[rng](i_0, i_1, i_2, ..., i_n)
//   [where i_x is a complete expression and not just a value]
// is syntactic sugar for:
//
//   switch(random[rng](0, n)) {
//     case 0: a = i_0;
//     case 1: a = i_1;
//     case 2: a = i_2;
//     ...
//     case n: a = i_n;
//   }
//
//==========================================================================

ExpEmit FxRandomPick::Emit(VMFunctionBuilder *build)
{
	unsigned i;

	assert(choices.Size() > 0);

	// Call BuiltinRandom to generate a random number.
	VMFunction *callfunc;
	auto sym = FindBuiltinFunction(NAME_BuiltinRandom);

	assert(sym);
	callfunc = sym->Variants[0].Implementation;

	FunctionCallEmitter emitters(callfunc);
	emitters.AddParameterPointerConst(rng);
	emitters.AddParameterIntConst(0);
	emitters.AddParameterIntConst(choices.Size() - 1);
	emitters.AddReturn(REGT_INT);
	auto resultreg = emitters.EmitCall(build);

	build->Emit(OP_IJMP, resultreg.RegNum, choices.Size());

	// Free the result register now. The simple code generation algorithm should
	// automatically pick it as the destination register for each case.
	resultreg.Free(build);

	// For floating point results, we need to get a new register, since we can't
	// reuse the integer one used to store the random result.
	if (ValueType->GetRegType() == REGT_FLOAT)
	{
		resultreg = ExpEmit(build, REGT_FLOAT);
		resultreg.Free(build);
	}

	// Allocate space for the jump table.
	size_t jumptable = build->Emit(OP_JMP, 0);
	for (i = 1; i < choices.Size(); ++i)
	{
		build->Emit(OP_JMP, 0);
	}

	// Emit each case
	TArray<size_t> finishes(choices.Size() - 1);
	for (unsigned i = 0; i < choices.Size(); ++i)
	{
		build->BackpatchToHere(jumptable + i);
		if (choices[i]->isConstant())
		{
			EmitLoad(build, resultreg, static_cast<FxConstant *>(choices[i])->GetValue());
		}
		else
		{
			ExpEmit casereg = choices[i]->Emit(build);
			if (casereg.RegNum != resultreg.RegNum)
			{ // The result of the case is in a different register from what
			  // was expected. Copy it to the one we wanted.

				resultreg.Reuse(build);	// This is really just for the assert in Reuse()
				build->Emit(ValueType->GetRegType() == REGT_INT ? OP_MOVE : OP_MOVEF, resultreg.RegNum, casereg.RegNum, 0);
				resultreg.Free(build);
			}
			// Free this register so the remaining cases can use it.
			casereg.Free(build);
		}
		// All but the final case needs a jump to the end of the expression's code.
		if (i + 1 < choices.Size())
		{
			size_t loc = build->Emit(OP_JMP, 0);
			finishes.Push(loc);
		}
	}
	// Backpatch each case (except the last, since it ends here) to jump to here.
	for (i = 0; i < choices.Size() - 1; ++i)
	{
		build->BackpatchToHere(finishes[i]);
	}
	// The result register needs to be in-use when we return.
	// It should have been freed earlier, so restore its in-use flag.
	resultreg.Reuse(build);
	choices.DeleteAndClear();
	choices.ShrinkToFit();
	return resultreg;
}

//==========================================================================
//
//
//
//==========================================================================
FxFRandom::FxFRandom(FRandom *r, FxExpression *mi, FxExpression *ma, const FScriptPosition &pos)
: FxRandom(EFX_FRandom, r, pos)
{
	assert(mi && ma);
	min = new FxFloatCast(mi);
	max = new FxFloatCast(ma);
	ValueType = TypeFloat64;
}

//==========================================================================
//
//
//
//==========================================================================

static double NativeFRandom(FRandom *rng, double min, double max)
{
	int random = (*rng)(0x40000000);
	double frandom = random / double(0x40000000);

	if (max < min)
	{
		std::swap(max, min);
	}
	return frandom * (max - min) + min;
}

DEFINE_ACTION_FUNCTION_NATIVE(DObject, BuiltinFRandom, NativeFRandom)
{
	PARAM_PROLOGUE;
	PARAM_POINTER(rng, FRandom);
	PARAM_FLOAT(min);
	PARAM_FLOAT(max);

	ACTION_RETURN_FLOAT(NativeFRandom(rng, min, max));
}

ExpEmit FxFRandom::Emit(VMFunctionBuilder *build)
{
	// Call the BuiltinFRandom function to generate a floating point random number..
	VMFunction *callfunc;
	auto sym = FindBuiltinFunction(NAME_BuiltinFRandom);

	assert(sym);
	callfunc = sym->Variants[0].Implementation;

	assert(min && max);

	FunctionCallEmitter emitters(callfunc);
	emitters.AddParameterPointerConst(rng);
	emitters.AddParameter(build, min);
	emitters.AddParameter(build, max);
	emitters.AddReturn(REGT_FLOAT);
	return emitters.EmitCall(build);
}

//==========================================================================
//
//
//
//==========================================================================

FxRandom2::FxRandom2(FRandom *r, FxExpression *m, const FScriptPosition &pos, bool nowarn)
: FxExpression(EFX_Random2, pos)
{
	rng = r;
	if (m) mask = new FxIntCast(m, nowarn);
	else mask = new FxConstant(-1, pos);
	ValueType = TypeSInt32;
}

//==========================================================================
//
//
//
//==========================================================================

FxRandom2::~FxRandom2()
{
	SAFE_DELETE(mask);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxRandom2::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(mask, ctx);
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

static int NativeRandom2(FRandom *rng, int maskval)
{
	return rng->Random2(maskval);
}

DEFINE_ACTION_FUNCTION_NATIVE(DObject, BuiltinRandom2, NativeRandom2)
{
	PARAM_PROLOGUE;
	PARAM_POINTER(rng, FRandom);
	PARAM_INT(maskval);
	ACTION_RETURN_INT(rng->Random2(maskval));
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxRandom2::Emit(VMFunctionBuilder *build)
{
	// Call the BuiltinRandom function to generate the random number.
	VMFunction *callfunc;
	auto sym = FindBuiltinFunction(NAME_BuiltinRandom2);

	assert(sym);
	callfunc = sym->Variants[0].Implementation;

	FunctionCallEmitter emitters(callfunc);

	emitters.AddParameterPointerConst(rng);
	emitters.AddParameter(build, mask);
	emitters.AddReturn(REGT_INT);
	return emitters.EmitCall(build);
}

//==========================================================================
//
//
//
//==========================================================================
FxRandomSeed::FxRandomSeed(FRandom * r, FxExpression *s, const FScriptPosition &pos, bool nowarn)
	: FxExpression(EFX_Random, pos)
{
	seed = new FxIntCast(s, nowarn);
	rng = r;
	ValueType = TypeVoid;
}

//==========================================================================
//
//
//
//==========================================================================

FxRandomSeed::~FxRandomSeed()
{
	SAFE_DELETE(seed);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxRandomSeed::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(seed, ctx);
	return this;
};


//==========================================================================
//
//
//
//==========================================================================

static void NativeRandomSeed(FRandom *rng, int seed)
{
	rng->Init(seed);
}

DEFINE_ACTION_FUNCTION_NATIVE(DObject, BuiltinRandomSeed, NativeRandomSeed)
{
	PARAM_PROLOGUE;
	PARAM_POINTER(rng, FRandom)
	PARAM_INT(seed);
	rng->Init(seed);
	return 0;
}

ExpEmit FxRandomSeed::Emit(VMFunctionBuilder *build)
{
	// Call DecoRandom to generate a random number.
	VMFunction *callfunc;
	auto sym = FindBuiltinFunction(NAME_BuiltinRandomSeed);

	assert(sym);
	callfunc = sym->Variants[0].Implementation;

	FunctionCallEmitter emitters(callfunc);
	emitters.AddParameterPointerConst(rng);
	emitters.AddParameter(build, seed);
	return emitters.EmitCall(build);
}

//==========================================================================
//
//
//
//==========================================================================

FxIdentifier::FxIdentifier(FName name, const FScriptPosition &pos)
: FxExpression(EFX_Identifier, pos)
{
	Identifier = name;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxIdentifier::Resolve(FCompileContext& ctx)
{
	PSymbol * sym;
	FxExpression *newex = nullptr;
	int num;
	
	CHECKRESOLVED();

	// Local variables have highest priority.
	FxLocalVariableDeclaration *local = ctx.FindLocalVariable(Identifier);
	if (local != nullptr)
	{
		if (local->ExprType == EFX_StaticArray)
		{
			auto x = new FxStaticArrayVariable(local, ScriptPosition);
			delete this;
			return x->Resolve(ctx);
		}
		else if (local->ValueType->GetRegType() != REGT_NIL)
		{
			auto x = new FxLocalVariable(local, ScriptPosition);
			delete this;
			return x->Resolve(ctx);
		}
		else
		{
			auto x = new FxStackVariable(local->ValueType, local->StackOffset, ScriptPosition);
			delete this;
			return x->Resolve(ctx);
		}
	}

	if (Identifier == NAME_Default)
	{
		if (ctx.Function == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Unable to access class defaults from constant declaration");
			delete this;
			return nullptr;
		}
		if (ctx.Function->Variants[0].SelfClass == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Unable to access class defaults from static function");
			delete this;
			return nullptr;
		}
		if (!isActor(ctx.Function->Variants[0].SelfClass))
		{
			ScriptPosition.Message(MSG_ERROR, "'Default' requires an actor type.");
			delete this;
			return nullptr;
		}

		FxExpression * x = new FxClassDefaults(new FxSelf(ScriptPosition), ScriptPosition);
		delete this;
		return x->Resolve(ctx);
	}

	// Ugh, the horror. Constants need to be taken from the owning class, but members from the self class to catch invalid accesses here...
	// see if the current class (if valid) defines something with this name.
	PSymbolTable *symtbl;

	// first check fields in self
	if ((sym = ctx.FindInSelfClass(Identifier, symtbl)) != nullptr)
	{
		if (sym->IsKindOf(RUNTIME_CLASS(PField)))
		{
			if (ctx.Function == nullptr)
			{
				ScriptPosition.Message(MSG_ERROR, "Unable to access class member %s from constant declaration", Identifier.GetChars());
				delete this;
				return nullptr;
			}
			FxExpression *self = new FxSelf(ScriptPosition);
			self = self->Resolve(ctx);
			newex = ResolveMember(ctx, ctx.Function->Variants[0].SelfClass, self, ctx.Function->Variants[0].SelfClass);
			ABORT(newex);
			goto foundit;
		}
	}

	// now check in the owning class.
	if (newex == nullptr && (sym = ctx.FindInClass(Identifier, symtbl)) != nullptr)
	{
		if (sym->IsKindOf(RUNTIME_CLASS(PSymbolConst)))
		{
			ScriptPosition.Message(MSG_DEBUGLOG, "Resolving name '%s' as class constant\n", Identifier.GetChars());
			newex = FxConstant::MakeConstant(sym, ScriptPosition);
			goto foundit;
		}
		else if (ctx.Function == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Unable to access class member %s from constant declaration", sym->SymbolName.GetChars());
			delete this;
			return nullptr;
		}
		// The following only applies to non-static content.
		// Static functions have no access to non-static parts of a class and should be able to see global identifiers of the same name.
		else if (ctx.Function->Variants[0].SelfClass != nullptr)
		{
			// Do this check for ZScript as well, so that a clearer error message can be printed. MSG_OPTERROR will default to MSG_ERROR there.
			if (ctx.Function->Variants[0].SelfClass != ctx.Class && sym->IsKindOf(RUNTIME_CLASS(PField)))
			{
				FxExpression *self = new FxSelf(ScriptPosition, true);
				self = self->Resolve(ctx);
				newex = ResolveMember(ctx, ctx.Class, self, ctx.Class);
				ABORT(newex);
				ScriptPosition.Message(MSG_OPTERROR, "Self pointer used in ambiguous context; VM execution may abort!");
				ctx.Unsafe = true;
				goto foundit;
			}
			else
			{
				if (sym->IsKindOf(RUNTIME_CLASS(PFunction)))
				{
					ScriptPosition.Message(MSG_ERROR, "Function '%s' used without ().\n", Identifier.GetChars());
					delete this;
					return nullptr;
				}
				else
				{
					ScriptPosition.Message(MSG_ERROR, "Invalid member identifier '%s'.\n", Identifier.GetChars());
					delete this;
					return nullptr;
				}
			}
		}
	}

	if (noglobal)
	{
		// This is needed to properly resolve class names on the left side of the member access operator
		ValueType = TypeError;
		return this;
	}

	// now check the global identifiers.
	if (newex == nullptr && (sym = ctx.FindGlobal(Identifier)) != nullptr)
	{
		if (sym->IsKindOf(RUNTIME_CLASS(PSymbolConst)))
		{
			ScriptPosition.Message(MSG_DEBUGLOG, "Resolving name '%s' as global constant\n", Identifier.GetChars());
			newex = FxConstant::MakeConstant(sym, ScriptPosition);
			goto foundit;
		}
		else if (sym->IsKindOf(RUNTIME_CLASS(PField)))
		{
			PField *vsym = static_cast<PField*>(sym);

			if (vsym->GetVersion() > ctx.Version)
			{
				ScriptPosition.Message(MSG_ERROR, "%s not accessible to %s", sym->SymbolName.GetChars(), ctx.VersionString.GetChars());
				delete this;
				return nullptr;
			}

			// internally defined global variable
			ScriptPosition.Message(MSG_DEBUGLOG, "Resolving name '%s' as global variable\n", Identifier.GetChars());

			if ((vsym->Flags & VARF_Deprecated))
			{
				if (sym->mVersion <= ctx.Version)
				{
					// Allow use of deprecated symbols in deprecated functions of the internal code. This is meant to allow deprecated code to remain as it was, 
					// even if it depends on some deprecated symbol. 
					// The main motivation here is to keep the deprecated static functions accessing the global level variable as they were.
					// Print these only if debug output is active and at the highest verbosity level.
					const bool internal = (ctx.Function->Variants[0].Flags & VARF_Deprecated) && Wads.GetLumpFile(ctx.Lump) == 0;

					ScriptPosition.Message(internal ? MSG_DEBUGMSG : MSG_WARNING, 
						"%sAccessing deprecated global variable %s - deprecated since %d.%d.%d", internal ? TEXTCOLOR_BLUE : "",
						sym->SymbolName.GetChars(), vsym->mVersion.major, vsym->mVersion.minor, vsym->mVersion.revision);
				}
			}
			

			newex = new FxGlobalVariable(static_cast<PField *>(sym), ScriptPosition);
			goto foundit;
		}
		else
		{
			ScriptPosition.Message(MSG_ERROR, "Invalid global identifier '%s'\n", Identifier.GetChars());
			delete this;
			return nullptr;
		}
	}

	// and line specials
	if (newex == nullptr && (num = P_FindLineSpecial(Identifier, nullptr, nullptr)))
	{
		ScriptPosition.Message(MSG_DEBUGLOG, "Resolving name '%s' as line special %d\n", Identifier.GetChars(), num);
		newex = new FxConstant(num, ScriptPosition);
		goto foundit;
	}

	if (auto *cvar = FindCVar(Identifier.GetChars(), nullptr))
	{
		if (cvar->GetFlags() & CVAR_USERINFO)
		{
			ScriptPosition.Message(MSG_ERROR, "Cannot access userinfo CVARs directly. Use GetCVar() instead.");
			delete this;
			return nullptr;
		}
		newex = new FxCVar(cvar, ScriptPosition);
		goto foundit;
	}
	
	ScriptPosition.Message(MSG_ERROR, "Unknown identifier '%s'", Identifier.GetChars());
	delete this;
	return nullptr;

foundit:
	delete this;
	return newex? newex->Resolve(ctx) : nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxIdentifier::ResolveMember(FCompileContext &ctx, PContainerType *classctx, FxExpression *&object, PContainerType *objtype)
{
	PSymbol *sym;
	PSymbolTable *symtbl;
	bool isclass = objtype->isClass();

	if (Identifier == NAME_Default)
	{
		if (!isActor(objtype))
		{
			ScriptPosition.Message(MSG_ERROR, "'Default' requires an actor type.");
			delete object;
			object = nullptr;
			return nullptr;
		}

		FxExpression * x = new FxClassDefaults(object, ScriptPosition);
		object = nullptr;
		delete this;
		return x->Resolve(ctx);
	}

	if (objtype != nullptr && (sym = objtype->Symbols.FindSymbolInTable(Identifier, symtbl)) != nullptr)
	{
		if (sym->IsKindOf(RUNTIME_CLASS(PSymbolConst)))
		{
			ScriptPosition.Message(MSG_DEBUGLOG, "Resolving name '%s' as %s constant\n", Identifier.GetChars(), isclass ? "class" : "struct");
			delete object;
			object = nullptr;
			return FxConstant::MakeConstant(sym, ScriptPosition);
		}
		else if (sym->IsKindOf(RUNTIME_CLASS(PField)))
		{
			PField *vsym = static_cast<PField*>(sym);
			if (vsym->GetVersion() > ctx.Version)
			{
				ScriptPosition.Message(MSG_ERROR, "%s not accessible to %s", sym->SymbolName.GetChars(), ctx.VersionString.GetChars());
				delete object;
				object = nullptr;
				return nullptr;
			}
			if ((vsym->Flags & VARF_Deprecated))
			{
				if (sym->mVersion <= ctx.Version)
				{
					ScriptPosition.Message(MSG_WARNING, "Accessing deprecated member variable %s - deprecated since %d.%d.%d", sym->SymbolName.GetChars(), vsym->mVersion.major, vsym->mVersion.minor, vsym->mVersion.revision);
				}
			}

			// We have 4 cases to consider here:
			// 1. The symbol is a static/meta member which is always accessible.
			// 2. This is a static function 
			// 3. This is an action function with a restricted self pointer
			// 4. This is a normal member or unrestricted action function.
			if ((vsym->Flags & VARF_Private) && symtbl != &classctx->Symbols)
			{
				ScriptPosition.Message(MSG_ERROR, "Private member %s not accessible", vsym->SymbolName.GetChars());
				delete object;
				object = nullptr;
				return nullptr;
			}
			auto cls_ctx = PType::toClass(classctx);
			auto cls_target = PType::toClass(objtype);
			// [ZZ] neither PSymbol, PField or PSymbolTable have the necessary information. so we need to do the more complex check here.
			if (vsym->Flags & VARF_Protected)
			{
				// early break.
				if (!cls_ctx || !cls_target)
				{
					ScriptPosition.Message(MSG_ERROR, "Protected member %s not accessible", vsym->SymbolName.GetChars());
					delete object;
					object = nullptr;
					return nullptr;
				}

				// find the class that declared this field.
				auto p = cls_target;
				while (p)
				{
					if (&p->Symbols == symtbl)
					{
						cls_target = p;
						break;
					}

					p = p->ParentType;
				}

				if (!cls_ctx->Descriptor->IsDescendantOf(cls_target->Descriptor))
				{
					ScriptPosition.Message(MSG_ERROR, "Protected member %s not accessible", vsym->SymbolName.GetChars());
					delete object;
					object = nullptr;
					return nullptr;
				}
			}

			auto x = isclass ? new FxClassMember(object, vsym, ScriptPosition) : new FxStructMember(object, vsym, ScriptPosition);
			object = nullptr;
			return x->Resolve(ctx);
		}
		else
		{
			if (sym->IsKindOf(RUNTIME_CLASS(PFunction)))
			{
				ScriptPosition.Message(MSG_ERROR, "Function '%s' used without ().\n", Identifier.GetChars());
			}
			else
			{
				ScriptPosition.Message(MSG_ERROR, "Invalid member identifier '%s'.\n", Identifier.GetChars());
			}
			delete object;
			object = nullptr;
			return nullptr;
		}
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Unknown identifier '%s'", Identifier.GetChars());
		delete object;
		object = nullptr;
		return nullptr;
	}
}

//==========================================================================
//
//
//
//==========================================================================

FxMemberIdentifier::FxMemberIdentifier(FxExpression *left, FName name, const FScriptPosition &pos)
	: FxIdentifier(name, pos)
{
	Object = left;
	ExprType = EFX_MemberIdentifier;
}

FxMemberIdentifier::~FxMemberIdentifier()
{
	SAFE_DELETE(Object);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxMemberIdentifier::Resolve(FCompileContext& ctx)
{
	PContainerType *ccls = nullptr;
	CHECKRESOLVED();

	if (Object->ExprType == EFX_Identifier)
	{
		auto id = static_cast<FxIdentifier *>(Object)->Identifier;
		// If the left side is a class name for a static member function call it needs to be resolved manually 
		// because the resulting value type would cause problems in nearly every other place where identifiers are being used.
		ccls = FindContainerType(id, ctx);
		if (ccls != nullptr)
		{
			static_cast<FxIdentifier *>(Object)->noglobal = true;
		}
		else
		{
			PType *type;
			// Another special case to deal with here is constants assigned to non-struct types. The code below cannot deal with them so it needs to be done here explicitly.
			// Thanks to the messed up search logic of the type system, which doesn't allow any search by type name for the basic types at all,
			// we have to do this manually, though and check for all types that may have values attached explicitly. 
			// (What's the point of attached fields to types if you cannot even search for the types...???)
			switch (id)
			{
			default:
				type = nullptr;
				break;

			case NAME_Byte:
			case NAME_uint8:
				type = TypeUInt8;
				break;

			case NAME_sByte:
			case NAME_int8:
				type = TypeSInt8;
				break;

			case NAME_uShort:
			case NAME_uint16:
				type = TypeUInt16;
				break;

			case NAME_Short:
			case NAME_int16:
				type = TypeSInt16;
				break;

			case NAME_Int:
				type = TypeSInt32;
				break;

			case NAME_uInt:
				type = TypeUInt32;
				break;

			case NAME_Float:
				type = TypeFloat32;
				break;

			case NAME_Double:
				type = TypeFloat64;
				break;
			}
			if (type != nullptr)
			{
				auto sym = type->Symbols.FindSymbol(Identifier, true);
				if (sym != nullptr)
				{
					// non-struct symbols must be constant numbers and can only be defined internally.
					assert(sym->IsKindOf(RUNTIME_CLASS(PSymbolConstNumeric)));
					auto sn = static_cast<PSymbolConstNumeric*>(sym);

					TypedVMValue vmv;
					if (sn->ValueType->isIntCompatible()) vmv = sn->Value;
					else vmv = sn->Float;
					auto x = new FxConstant(sn->ValueType, vmv, ScriptPosition);
					delete this;
					return x->Resolve(ctx);
				}
			}
		}
	}

	SAFE_RESOLVE(Object, ctx);

	// check for class or struct constants if the left side is a type name.
	if (Object->ValueType == TypeError)
	{
		if (ccls != nullptr)
		{
			PSymbol *sym;
			if ((sym = ccls->Symbols.FindSymbol(Identifier, true)) != nullptr)
			{
				if (sym->IsKindOf(RUNTIME_CLASS(PSymbolConst)))
				{
					ScriptPosition.Message(MSG_DEBUGLOG, "Resolving name '%s.%s' as constant\n", ccls->TypeName.GetChars(), Identifier.GetChars());
					delete this;
					return FxConstant::MakeConstant(sym, ScriptPosition);
				}
				else
				{
					auto f = dyn_cast<PField>(sym);
					if (f != nullptr && (f->Flags & (VARF_Static | VARF_ReadOnly | VARF_Meta)) == (VARF_Static | VARF_ReadOnly))
					{
						auto x = new FxGlobalVariable(f, ScriptPosition);
						delete this;
						return x->Resolve(ctx);
					}
					else
					{
						ScriptPosition.Message(MSG_ERROR, "Unable to access '%s.%s' in a static context\n", ccls->TypeName.GetChars(), Identifier.GetChars());
						delete this;
						return nullptr;
					}
				}
			}
			else
			{
				ScriptPosition.Message(MSG_ERROR, "%s is not a member of %s", Identifier.GetChars(), ccls->TypeName.GetChars());
				delete this;
				return nullptr;
			}
		}
	}

	// allow accessing the color channels by mapping the type to a matching struct which defines them.
	if (Object->ValueType == TypeColor)
	{
		Object->ValueType = TypeColorStruct;
	}
	if (Object->ValueType->isRealPointer())
	{
		auto ptype = Object->ValueType->toPointer()->PointedType;
		if (ptype->isContainer())
		{
			auto ret = ResolveMember(ctx, ctx.Class, Object, static_cast<PContainerType *>(ptype));
			delete this;
			return ret;
		}
	}
	else if (Object->ValueType->isStruct())
	{
		auto ret = ResolveMember(ctx, ctx.Class, Object, static_cast<PStruct *>(Object->ValueType));
		delete this;
		return ret;
	}

	ScriptPosition.Message(MSG_ERROR, "Left side of %s is not a struct or class", Identifier.GetChars());
	delete this;
	return nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

FxLocalVariable::FxLocalVariable(FxLocalVariableDeclaration *var, const FScriptPosition &sc)
	: FxExpression(EFX_LocalVariable, sc)
{
	Variable = var;
	ValueType = var->ValueType;
	AddressRequested = false;
	RegOffset = 0;
}

FxExpression *FxLocalVariable::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	return this;
}

bool FxLocalVariable::RequestAddress(FCompileContext &ctx, bool *writable)
{
	AddressRequested = true;
	if (writable != nullptr) *writable = !ctx.CheckWritable(Variable->VarFlags);
	return true;
}
	
ExpEmit FxLocalVariable::Emit(VMFunctionBuilder *build)
{
	// 'Out' variables are actually pointers but this fact must be hidden to the script.
	if (Variable->VarFlags & VARF_Out)
	{
		if (!AddressRequested)
		{
			ExpEmit reg(build, ValueType->GetRegType(), ValueType->GetRegCount());
			build->Emit(ValueType->GetLoadOp(), reg.RegNum, Variable->RegNum, build->GetConstantInt(RegOffset));
			return reg;
		}
		else
		{
			if (RegOffset == 0) return ExpEmit(Variable->RegNum, REGT_POINTER, false, true);
			ExpEmit reg(build, REGT_POINTER);
			build->Emit(OP_ADDA_RK, reg.RegNum, Variable->RegNum, build->GetConstantInt(RegOffset));
			return reg;
		}
	}
	else
	{
		ExpEmit ret(Variable->RegNum + RegOffset, Variable->ValueType->GetRegType(), false, true);
		ret.RegCount = ValueType->GetRegCount();
		if (AddressRequested) ret.Target = true;
		return ret;
	}
}


//==========================================================================
//
//
//
//==========================================================================

FxStaticArrayVariable::FxStaticArrayVariable(FxLocalVariableDeclaration *var, const FScriptPosition &sc)
	: FxExpression(EFX_StaticArrayVariable, sc)
{
	Variable = static_cast<FxStaticArray*>(var);
	ValueType = Variable->ValueType;
}

FxExpression *FxStaticArrayVariable::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	return this;
}

bool FxStaticArrayVariable::RequestAddress(FCompileContext &ctx, bool *writable)
{
	AddressRequested = true;
	if (writable != nullptr) *writable = false;
	return true;
}

ExpEmit FxStaticArrayVariable::Emit(VMFunctionBuilder *build)
{
	// returns the first const register for this array
	return ExpEmit(Variable->StackOffset, Variable->ElementType->GetRegType(), true, false);
}


//==========================================================================
//
//
//
//==========================================================================

FxSelf::FxSelf(const FScriptPosition &pos, bool deccheck)
: FxExpression(EFX_Self, pos)
{
	check = deccheck;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxSelf::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	if (ctx.Function == nullptr || ctx.Function->Variants[0].SelfClass == nullptr)
	{
		ScriptPosition.Message(MSG_ERROR, "self used outside of a member function");
		delete this;
		return nullptr;
	}
	ValueType = NewPointer(ctx.Function->Variants[0].SelfClass);
	return this;
}  

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxSelf::Emit(VMFunctionBuilder *build)
{
	if (check)
	{
		build->Emit(OP_EQA_R, 1, 0, 1);
		build->Emit(OP_JMP, 1);
		build->Emit(OP_THROW, 2, X_BAD_SELF);
	}
	// self is always the first pointer passed to the function
	return ExpEmit(0, REGT_POINTER, false, true);
}


//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxSuper::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	if (ctx.Function == nullptr || ctx.Function->Variants[0].SelfClass == nullptr)
	{
		ScriptPosition.Message(MSG_ERROR, "super used outside of a member function");
		delete this;
		return nullptr;
	}
	ValueType = TypeError;	// this intentionally resolves to an invalid type so that it cannot be used outside of super calls.
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

FxClassDefaults::FxClassDefaults(FxExpression *X, const FScriptPosition &pos)
	: FxExpression(EFX_ClassDefaults, pos)
{
	obj = X;
}

FxClassDefaults::~FxClassDefaults()
{
	SAFE_DELETE(obj);
}


//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxClassDefaults::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(obj, ctx);
	assert(obj->ValueType->isRealPointer());
	ValueType = NewPointer(obj->ValueType->toPointer()->PointedType, true);
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxClassDefaults::Emit(VMFunctionBuilder *build)
{
	ExpEmit ob = obj->Emit(build);
	ob.Free(build);
	ExpEmit meta(build, REGT_POINTER);
	build->Emit(OP_CLSS, meta.RegNum, ob.RegNum);
	build->Emit(OP_LP, meta.RegNum, meta.RegNum, build->GetConstantInt(myoffsetof(PClass, Defaults)));
	return meta;

}

//==========================================================================
//
//
//
//==========================================================================

FxGlobalVariable::FxGlobalVariable(PField* mem, const FScriptPosition &pos)
	: FxMemberBase(EFX_GlobalVariable, mem, pos)
{
}

//==========================================================================
//
//
//
//==========================================================================

bool FxGlobalVariable::RequestAddress(FCompileContext &ctx, bool *writable)
{
	AddressRequested = true;
	if (writable != nullptr) *writable = AddressWritable && !ctx.CheckWritable(membervar->Flags);
	return true;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxGlobalVariable::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	ValueType = membervar->Type;
	return this;
}

ExpEmit FxGlobalVariable::Emit(VMFunctionBuilder *build)
{
	ExpEmit obj(build, REGT_POINTER);

	build->Emit(OP_LKP, obj.RegNum, build->GetConstantAddress((void*)(intptr_t)membervar->Offset));
	if (AddressRequested)
	{
		return obj;
	}

	ExpEmit loc(build, membervar->Type->GetRegType(), membervar->Type->GetRegCount());

	if (membervar->BitValue == -1)
	{
		int offsetreg = build->GetConstantInt(0);
		build->Emit(membervar->Type->GetLoadOp(), loc.RegNum, obj.RegNum, offsetreg);
	}
	else
	{
		build->Emit(OP_LBIT, loc.RegNum, obj.RegNum, 1 << membervar->BitValue);
	}
	obj.Free(build);
	return loc;
}


//==========================================================================
//
//
//
//==========================================================================

FxCVar::FxCVar(FBaseCVar *cvar, const FScriptPosition &pos)
	: FxExpression(EFX_CVar, pos)
{
	CVar = cvar;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxCVar::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	switch (CVar->GetRealType())
	{
	case CVAR_Bool:
	case CVAR_DummyBool:
		ValueType = TypeBool;
		break;

	case CVAR_Int:
	case CVAR_DummyInt:
		ValueType = TypeSInt32;
		break;

	case CVAR_Color:
		ValueType = TypeColor;
		break;

	case CVAR_Float:
		ValueType = TypeFloat64;
		break;

	case CVAR_String:
		ValueType = TypeString;
		break;

	default:
		ScriptPosition.Message(MSG_ERROR, "Unknown CVar type for %s", CVar->GetName());
		delete this;
		return nullptr;
	}
	return this;
}

ExpEmit FxCVar::Emit(VMFunctionBuilder *build)
{
	ExpEmit dest(build, ValueType->GetRegType());
	ExpEmit addr(build, REGT_POINTER);
	int nul = build->GetConstantInt(0);
	switch (CVar->GetRealType())
	{
	case CVAR_Int:
		build->Emit(OP_LKP, addr.RegNum, build->GetConstantAddress(&static_cast<FIntCVar *>(CVar)->Value));
		build->Emit(OP_LW, dest.RegNum, addr.RegNum, nul);
		break;

	case CVAR_Color:
		build->Emit(OP_LKP, addr.RegNum, build->GetConstantAddress(&static_cast<FColorCVar *>(CVar)->Value));
		build->Emit(OP_LW, dest.RegNum, addr.RegNum, nul);
		break;

	case CVAR_Float:
		build->Emit(OP_LKP, addr.RegNum, build->GetConstantAddress(&static_cast<FFloatCVar *>(CVar)->Value));
		build->Emit(OP_LSP, dest.RegNum, addr.RegNum, nul);
		break;

	case CVAR_Bool:
		build->Emit(OP_LKP, addr.RegNum, build->GetConstantAddress(&static_cast<FBoolCVar *>(CVar)->Value));
		build->Emit(OP_LBU, dest.RegNum, addr.RegNum, nul);
		break;

	case CVAR_String:
		build->Emit(OP_LKP, addr.RegNum, build->GetConstantAddress(&static_cast<FStringCVar *>(CVar)->Value));
		build->Emit(OP_LCS, dest.RegNum, addr.RegNum, nul);
		break;

	case CVAR_DummyBool:
	{
		int *pVal;
		auto cv = static_cast<FFlagCVar *>(CVar);
		auto vcv = &cv->ValueVar;
		pVal = &vcv->Value;
		build->Emit(OP_LKP, addr.RegNum, build->GetConstantAddress(pVal));
		build->Emit(OP_LW, dest.RegNum, addr.RegNum, nul);
		build->Emit(OP_SRL_RI, dest.RegNum, dest.RegNum, cv->BitNum);
		build->Emit(OP_AND_RK, dest.RegNum, dest.RegNum, build->GetConstantInt(1));
		break;
	}

	case CVAR_DummyInt:
	{
		auto cv = static_cast<FMaskCVar *>(CVar);
		build->Emit(OP_LKP, addr.RegNum, build->GetConstantAddress(&cv->ValueVar.Value));
		build->Emit(OP_LW, dest.RegNum, addr.RegNum, nul);
		build->Emit(OP_AND_RK, dest.RegNum, dest.RegNum, build->GetConstantInt(cv->BitVal));
		build->Emit(OP_SRL_RI, dest.RegNum, dest.RegNum, cv->BitNum);
		break;
	}

	default:
		assert(false && "Unsupported CVar type");
		break;
	}
	addr.Free(build);
	return dest;
}


//==========================================================================
//
//
//
//==========================================================================

FxStackVariable::FxStackVariable(PType *type, int offset, const FScriptPosition &pos)
	: FxMemberBase(EFX_StackVariable, Create<PField>(NAME_None, type, 0, offset), pos)
{
}

//==========================================================================
//
// force delete the PField because we know we won't need it anymore
// and it won't get GC'd until the compiler finishes.
//
//==========================================================================

FxStackVariable::~FxStackVariable()
{
	membervar->ObjectFlags |= OF_YesReallyDelete;
	delete membervar;
}

//==========================================================================
//
//
//
//==========================================================================

bool FxStackVariable::RequestAddress(FCompileContext &ctx, bool *writable)
{
	AddressRequested = true;
	if (writable != nullptr) *writable = AddressWritable && !ctx.CheckWritable(membervar->Flags);
	return true;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxStackVariable::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	ValueType = membervar->Type;
	return this;
}

ExpEmit FxStackVariable::Emit(VMFunctionBuilder *build)
{
	int offsetreg = -1;
	
	if (membervar->Offset != 0) offsetreg = build->GetConstantInt((int)membervar->Offset);

	if (AddressRequested)
	{
		if (offsetreg >= 0)
		{
			ExpEmit obj(build, REGT_POINTER);
			build->Emit(OP_ADDA_RK, obj.RegNum, build->FramePointer.RegNum, offsetreg);
			return obj;
		}
		else
		{
			return build->FramePointer;
		}
	}
	ExpEmit loc(build, membervar->Type->GetRegType(), membervar->Type->GetRegCount());

	if (membervar->BitValue == -1)
	{
		if (offsetreg == -1) offsetreg = build->GetConstantInt(0);
		auto op = membervar->Type->GetLoadOp();
		if (op == OP_LO)
			op = OP_LP;
		build->Emit(op, loc.RegNum, build->FramePointer.RegNum, offsetreg);
	}
	else
	{
		ExpEmit obj(build, REGT_POINTER);
		if (offsetreg >= 0) build->Emit(OP_ADDA_RK, obj.RegNum, build->FramePointer.RegNum, offsetreg);
		obj.Free(build);
		build->Emit(OP_LBIT, loc.RegNum, obj.RegNum, 1 << membervar->BitValue);
	}
	return loc;
}


//==========================================================================
//
//
//
//==========================================================================
FxMemberBase::FxMemberBase(EFxType type, PField *f, const FScriptPosition &p)
	:FxExpression(type, p), membervar(f)
{
}


FxStructMember::FxStructMember(FxExpression *x, PField* mem, const FScriptPosition &pos)
	: FxMemberBase(EFX_StructMember, mem, pos)
{
	classx = x;
}

//==========================================================================
//
//
//
//==========================================================================

FxStructMember::~FxStructMember()
{
	SAFE_DELETE(classx);
}

//==========================================================================
//
//
//
//==========================================================================

bool FxStructMember::RequestAddress(FCompileContext &ctx, bool *writable)
{
	AddressRequested = true;
	if (membervar->Flags & VARF_Meta)
	{
		// Meta variables are read only.
		*writable = false;
	}
	else if (writable != nullptr)
	{
		// [ZZ] original check.
		bool bWritable = (AddressWritable && !ctx.CheckWritable(membervar->Flags) &&
			(!classx->ValueType->isPointer() || !classx->ValueType->toPointer()->IsConst));
		// [ZZ] implement write barrier between different scopes
		if (bWritable)
		{
			int outerflags = 0;
			if (ctx.Function)
			{
				outerflags = ctx.Function->Variants[0].Flags;
				if (((outerflags & (VARF_VirtualScope | VARF_Virtual)) == (VARF_VirtualScope | VARF_Virtual)) && ctx.Class)
					outerflags = FScopeBarrier::FlagsFromSide(FScopeBarrier::SideFromObjectFlags(ctx.Class->ScopeFlags));
			}
			FScopeBarrier scopeBarrier(outerflags, FScopeBarrier::FlagsFromSide(BarrierSide), membervar->SymbolName.GetChars());
			if (!scopeBarrier.writable)
				bWritable = false;
		}

		*writable = bWritable;
	}
	return true;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxStructMember::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(classx, ctx);

	if (membervar->SymbolName == NAME_Default)
	{
		if (!classx->ValueType->isObjectPointer()
			|| !static_cast<PObjectPointer *>(classx->ValueType)->PointedClass()->IsDescendantOf(RUNTIME_CLASS(AActor)))
		{
			ScriptPosition.Message(MSG_ERROR, "'Default' requires an actor type");
			delete this;
			return nullptr;
		}
		FxExpression * x = new FxClassDefaults(classx, ScriptPosition);
		classx = nullptr;
		delete this;
		return x->Resolve(ctx);
	}

	// [ZZ] support magic
	int outerflags = 0;
	if (ctx.Function)
	{
		outerflags = ctx.Function->Variants[0].Flags;
		if (((outerflags & (VARF_VirtualScope | VARF_Virtual)) == (VARF_VirtualScope | VARF_Virtual)) && ctx.Class)
			outerflags = FScopeBarrier::FlagsFromSide(FScopeBarrier::SideFromObjectFlags(ctx.Class->ScopeFlags));
	}
	FScopeBarrier scopeBarrier(outerflags, membervar->Flags, membervar->SymbolName.GetChars());
	if (!scopeBarrier.readable)
	{
		ScriptPosition.Message(MSG_ERROR, "%s", scopeBarrier.readerror.GetChars());
		delete this;
		return nullptr;
	}

	BarrierSide = scopeBarrier.sidelast;
	if (classx->ExprType == EFX_StructMember && ExprType == EFX_StructMember) // note: only do this for structs now
	{
		FxStructMember* pmember = (FxStructMember*)classx;
		if (BarrierSide == FScopeBarrier::Side_PlainData && pmember)
			BarrierSide = pmember->BarrierSide;
	}

	// Even though this is global, static and readonly, we still need to do the scope checks for consistency.
	if ((membervar->Flags & (VARF_Static | VARF_ReadOnly | VARF_Meta)) == (VARF_Static | VARF_ReadOnly))
	{
		// This is a static constant array, which is stored at a constant address, like a global variable.
		auto x = new FxGlobalVariable(membervar, ScriptPosition);
		delete this;
		return x->Resolve(ctx);
	}

	if (classx->ValueType->isPointer())
	{
		PPointer *ptrtype = classx->ValueType->toPointer();
		if (ptrtype == nullptr || !ptrtype->PointedType->isContainer())
		{
			ScriptPosition.Message(MSG_ERROR, "Member variable requires a struct or class object");
			delete this;
			return nullptr;
		}
	}
	else if (classx->ValueType->isStruct())
	{
		// if this is a struct within a class or another struct we can simplify the expression by creating a Create<PField> with a cumulative offset.
		if (classx->ExprType == EFX_ClassMember || classx->ExprType == EFX_StructMember || classx->ExprType == EFX_GlobalVariable || classx->ExprType == EFX_StackVariable)
		{
			auto parentfield = static_cast<FxMemberBase *>(classx)->membervar;
			// PFields are garbage collected so this will be automatically taken care of later.
			// [ZZ] call ChangeSideInFlags to ensure that we don't get ui+play
			auto newfield = Create<PField>(NAME_None, membervar->Type, FScopeBarrier::ChangeSideInFlags(membervar->Flags | parentfield->Flags, BarrierSide), membervar->Offset + parentfield->Offset);
			newfield->BitValue = membervar->BitValue;
			static_cast<FxMemberBase *>(classx)->membervar = newfield;
			classx->isresolved = false;	// re-resolve the parent so it can also check if it can be optimized away.
			auto x = classx->Resolve(ctx);
			classx = nullptr;
			return x;
		}
		else if (classx->ExprType == EFX_LocalVariable && classx->IsVector())	// vectors are a special case because they are held in registers
		{
			// since this is a vector, all potential things that may get here are single float or an xy-vector.
			auto locvar = static_cast<FxLocalVariable *>(classx);
			locvar->RegOffset = int(membervar->Offset / 8);
			locvar->ValueType = membervar->Type;
			classx = nullptr;
			delete this;
			return locvar;
		}
		else if (classx->ExprType == EFX_LocalVariable && classx->ValueType == TypeColorStruct)
		{
			// This needs special treatment because it'd require accessing the register via address.
			// Fortunately this is the only place where this kind of access is ever needed so an explicit handling is acceptable.
			int bits;
			switch (membervar->SymbolName.GetIndex())
			{
			case NAME_a: bits = 24; break;
			case NAME_r: bits = 16; break;
			case NAME_g: bits = 8; break;
			case NAME_b: default: bits = 0; break;
			}
			classx->ValueType = TypeColor;	// need to set it back.
			FxExpression *x = classx;
			if (bits > 0) x = new FxShift(TK_URShift, x, new FxConstant(bits, ScriptPosition));
			x = new FxBitOp('&', x, new FxConstant(255, ScriptPosition));
			classx = nullptr;
			delete this;
			return x->Resolve(ctx);
		}
		else
		{
			if (!(classx->RequestAddress(ctx, &AddressWritable)))
			{
				ScriptPosition.Message(MSG_ERROR, "Unable to dereference left side of %s", membervar->SymbolName.GetChars());
				delete this;
				return nullptr;
			}
		}
	}
	ValueType = membervar->Type;
	return this;
}

ExpEmit FxStructMember::Emit(VMFunctionBuilder *build)
{
	ExpEmit obj = classx->Emit(build);
	assert(obj.RegType == REGT_POINTER);

	if (obj.Konst)
	{
		// If the situation where we are dereferencing a constant
		// pointer is common, then it would probably be worthwhile
		// to add new opcodes for those. But as of right now, I
		// don't expect it to be a particularly common case.
		ExpEmit newobj(build, REGT_POINTER);
		build->Emit(OP_LKP, newobj.RegNum, obj.RegNum);
		obj = newobj;
	}

	if (membervar->Flags & VARF_Meta)
	{
		obj.Free(build);
		ExpEmit meta(build, REGT_POINTER);
		build->Emit(OP_META, meta.RegNum, obj.RegNum);
		obj = meta;
	}

	if (AddressRequested)
	{
		if (membervar->Offset == 0)
		{
			return obj;
		}
		obj.Free(build);
		ExpEmit out(build, REGT_POINTER);
		build->Emit(OP_ADDA_RK, out.RegNum, obj.RegNum, build->GetConstantInt((int)membervar->Offset));
		return out;
	}

	int offsetreg = build->GetConstantInt((int)membervar->Offset);
	ExpEmit loc(build, membervar->Type->GetRegType(), membervar->Type->GetRegCount());

	if (membervar->BitValue == -1)
	{
		build->Emit(membervar->Type->GetLoadOp(), loc.RegNum, obj.RegNum, offsetreg);
	}
	else
	{
		ExpEmit out(build, REGT_POINTER);
		build->Emit(OP_ADDA_RK, out.RegNum, obj.RegNum, offsetreg);
		build->Emit(OP_LBIT, loc.RegNum, out.RegNum, 1 << membervar->BitValue);
		out.Free(build);
	}
	obj.Free(build);
	return loc;
}


//==========================================================================
//
//
//
//==========================================================================

FxClassMember::FxClassMember(FxExpression *x, PField* mem, const FScriptPosition &pos)
: FxStructMember(x, mem, pos)
{
	ExprType = EFX_ClassMember;
}

//==========================================================================
//
//
//
//==========================================================================

FxArrayElement::FxArrayElement(FxExpression *base, FxExpression *_index)
:FxExpression(EFX_ArrayElement, base->ScriptPosition)
{
	Array=base;
	index = _index;
	AddressRequested = false;
	AddressWritable = false;
	SizeAddr = ~0u;
}

//==========================================================================
//
//
//
//==========================================================================

FxArrayElement::~FxArrayElement()
{
	SAFE_DELETE(Array);
	SAFE_DELETE(index);
}

//==========================================================================
//
//
//
//==========================================================================

bool FxArrayElement::RequestAddress(FCompileContext &ctx, bool *writable)
{
	AddressRequested = true;
	if (writable != nullptr) *writable = AddressWritable;
	return true;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxArrayElement::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Array,ctx);
	SAFE_RESOLVE(index,ctx);

	if (index->ValueType->GetRegType() == REGT_FLOAT /* lax */)
	{
		// DECORATE allows floats here so cast them to int.
		index = new FxIntCast(index, ctx.FromDecorate);
		index = index->Resolve(ctx);
		if (index == nullptr) 
		{
			delete this;
			return nullptr;
		}
	}
	if (!index->IsInteger())
	{
		ScriptPosition.Message(MSG_ERROR, "Array index must be integer");
		delete this;
		return nullptr;
	}

	PArray *arraytype = nullptr;
	PType *elementtype = nullptr;
	if (Array->IsDynamicArray())
	{
		PDynArray *darraytype = static_cast<PDynArray*>(Array->ValueType);
		elementtype = darraytype->ElementType;
		Array->ValueType = NewPointer(NewStaticArray(elementtype));	// change type so that this can use the code for resizable arrays unchanged.
		arrayispointer = true;
	}
	else
	{
		if (!Array->ValueType->isArray())
		{
			// Check if we got a pointer to an array. Some native data structures (like the line list in sectors) use this.
			PPointer *ptype = Array->ValueType->toPointer();
			if (ptype == nullptr || !ptype->PointedType->isArray())
			{
				ScriptPosition.Message(MSG_ERROR, "'[]' can only be used with arrays.");
				delete this;
				return nullptr;
			}
			arraytype = static_cast<PArray*>(ptype->PointedType);
			arrayispointer = true;
		}
		else
		{
			arraytype = static_cast<PArray*>(Array->ValueType);
		}
		elementtype = arraytype->ElementType;
	}

	if (Array->isStaticArray())
	{
		// if this is an array within a class or another struct we can simplify the expression by creating a Create<PField> with a cumulative offset.
		if (Array->ExprType == EFX_ClassMember || Array->ExprType == EFX_StructMember || Array->ExprType == EFX_GlobalVariable || Array->ExprType == EFX_StackVariable)
		{
			auto parentfield = static_cast<FxMemberBase *>(Array)->membervar;
			SizeAddr = parentfield->Offset + sizeof(void*);
		}
		else if (Array->ExprType == EFX_ArrayElement)
		{
			SizeAddr = ~0u;
		}
		else
		{
			ScriptPosition.Message(MSG_ERROR, "Invalid resizable array");
			delete this;
			return nullptr;
		}
	}
	// constant indices can only be resolved at compile time for statically sized arrays.
	else if (index->isConstant() && arraytype != nullptr && !arrayispointer)
	{
		unsigned indexval = static_cast<FxConstant *>(index)->GetValue().GetInt();
		if (indexval >= arraytype->ElementCount)
		{
			ScriptPosition.Message(MSG_ERROR, "Array index out of bounds");
			delete this;
			return nullptr;
		}

		// if this is an array within a class or another struct we can simplify the expression by creating a Create<PField> with a cumulative offset.
		if (Array->ExprType == EFX_ClassMember || Array->ExprType == EFX_StructMember || Array->ExprType == EFX_GlobalVariable || Array->ExprType == EFX_StackVariable)
		{
			auto parentfield = static_cast<FxMemberBase *>(Array)->membervar;
			// PFields are garbage collected so this will be automatically taken care of later.
			auto newfield = Create<PField>(NAME_None, elementtype, parentfield->Flags, indexval * arraytype->ElementSize + parentfield->Offset);
			static_cast<FxMemberBase *>(Array)->membervar = newfield;
			Array->isresolved = false;	// re-resolve the parent so it can also check if it can be optimized away.
			auto x = Array->Resolve(ctx);
			Array = nullptr;
			return x;
		}
	}

	ValueType = elementtype;
	if (!Array->RequestAddress(ctx, &AddressWritable))
	{
		ScriptPosition.Message(MSG_ERROR, "Unable to dereference array.");
		delete this;
		return nullptr;
	}
	return this;
}

//==========================================================================
//
// in its current state this won't be able to do more than handle the args array.
//
//==========================================================================

ExpEmit FxArrayElement::Emit(VMFunctionBuilder *build)
{
	PArray *arraytype;
	
	if (arrayispointer)
	{
		auto ptr = Array->ValueType->toPointer();
		if (ptr != nullptr)
		{
			arraytype = static_cast<PArray*>(ptr->PointedType);
		}
		else
		{
			ScriptPosition.Message(MSG_ERROR, "Internal error when generating code for array access");
			return ExpEmit();
		}
	}
	else
	{
		arraytype = static_cast<PArray*>(Array->ValueType);
	}
	ExpEmit arrayvar = Array->Emit(build);
	ExpEmit start;
	ExpEmit bound;
	bool nestedarray = false;
	
	if (SizeAddr != ~0u)
	{
		bool ismeta = Array->ExprType == EFX_ClassMember && static_cast<FxClassMember*>(Array)->membervar->Flags & VARF_Meta;

		start = ExpEmit(build, REGT_POINTER);
		build->Emit(OP_LP, start.RegNum, arrayvar.RegNum, build->GetConstantInt(0));

		auto f = Create<PField>(NAME_None, TypeUInt32, ismeta? VARF_Meta : 0, SizeAddr);
		auto arraymemberbase = static_cast<FxMemberBase *>(Array);

		auto origmembervar = arraymemberbase->membervar;
		auto origaddrreq = arraymemberbase->AddressRequested;
		auto origvaluetype = Array->ValueType;

		arraymemberbase->membervar = f;
		arraymemberbase->AddressRequested = false;
		Array->ValueType = TypeUInt32;

		bound = Array->Emit(build);

		arraymemberbase->membervar = origmembervar;
		arraymemberbase->AddressRequested = origaddrreq;
		Array->ValueType = origvaluetype;

		arrayvar.Free(build);
	}
	else if (Array->ExprType == EFX_ArrayElement && Array->isStaticArray())
	{
		bound = ExpEmit(build, REGT_INT);
		build->Emit(OP_LW, bound.RegNum, arrayvar.RegNum, build->GetConstantInt(myoffsetof(FArray, Count)));

		arrayvar.Free(build);
		start = ExpEmit(build, REGT_POINTER);
		build->Emit(OP_LP, start.RegNum, arrayvar.RegNum, build->GetConstantInt(0));

		nestedarray = true;
	}
	else start = arrayvar;

	if (index->isConstant())
	{
		unsigned indexval = static_cast<FxConstant *>(index)->GetValue().GetInt();
		assert(SizeAddr != ~0u || nestedarray || (indexval < arraytype->ElementCount && "Array index out of bounds"));

		// For resizable arrays we even need to check the bounds if if the index is constant because they are not known at compile time.
		if (SizeAddr != ~0u || nestedarray)
		{
			ExpEmit indexreg(build, REGT_INT);
			build->EmitLoadInt(indexreg.RegNum, indexval);
			build->Emit(OP_BOUND_R, indexreg.RegNum, bound.RegNum);
			indexreg.Free(build);
			bound.Free(build);
		}
		if (AddressRequested)
		{
			if (indexval != 0)
			{
				indexval *= arraytype->ElementSize;
				if (!start.Fixed)
				{
					build->Emit(OP_ADDA_RK, start.RegNum, start.RegNum, build->GetConstantInt(indexval));
				}
				else
				{
					// do not clobber local variables.
					ExpEmit temp(build, start.RegType);
					build->Emit(OP_ADDA_RK, temp.RegNum, start.RegNum, build->GetConstantInt(indexval));
					start.Free(build);
					start = temp;
				}
			}
			return start;
		}
		else if (!start.Konst)
		{
			start.Free(build);
			ExpEmit dest(build, ValueType->GetRegType());
			build->Emit(arraytype->ElementType->GetLoadOp(), dest.RegNum, start.RegNum, build->GetConstantInt(indexval* arraytype->ElementSize));
			return dest;
		}
		else
		{
			static int LK_Ops[] = { OP_LK, OP_LKF, OP_LKS, OP_LKP };
			assert(start.RegType == ValueType->GetRegType());
			ExpEmit dest(build, start.RegType);
			build->Emit(LK_Ops[start.RegType], dest.RegNum, start.RegNum + indexval);
			return dest;
		}
	}
	else
	{
		ExpEmit indexv(index->Emit(build));
		if (SizeAddr != ~0u || nestedarray)
		{
			build->Emit(OP_BOUND_R, indexv.RegNum, bound.RegNum);
			bound.Free(build);
		}
		else if (arraytype->ElementCount > 65535)
		{
			build->Emit(OP_BOUND_K, indexv.RegNum, build->GetConstantInt(arraytype->ElementCount));
		}
		else
		{
			build->Emit(OP_BOUND, indexv.RegNum, arraytype->ElementCount);
		}

		if (!start.Konst)
		{
			int shiftbits = 0;
			while (1u << shiftbits < arraytype->ElementSize)
			{
				shiftbits++;
			}
			ExpEmit indexwork = indexv.Fixed && arraytype->ElementSize > 1 ? ExpEmit(build, indexv.RegType) : indexv;
			if (1u << shiftbits == arraytype->ElementSize)
			{
				if (shiftbits > 0)
				{
					build->Emit(OP_SLL_RI, indexwork.RegNum, indexv.RegNum, shiftbits);
				}
			}
			else
			{
				// A shift won't do, so use a multiplication
				build->Emit(OP_MUL_RK, indexwork.RegNum, indexv.RegNum, build->GetConstantInt(arraytype->ElementSize));
			}
			indexwork.Free(build);

			if (AddressRequested)
			{
				start.Free(build);
				// do not clobber local variables.
				ExpEmit temp(build, start.RegType);
				build->Emit(OP_ADDA_RR, temp.RegNum, start.RegNum, indexwork.RegNum);
				return temp;
			}
			else
			{
				start.Free(build);
				ExpEmit dest(build, ValueType->GetRegType(), ValueType->GetRegCount());
				// added 1 to use the *_R version that takes the offset from a register
				build->Emit(arraytype->ElementType->GetLoadOp() + 1, dest.RegNum, start.RegNum, indexwork.RegNum);
				return dest;
			}
		}
		else
		{
			static int LKR_Ops[] = { OP_LK_R, OP_LKF_R, OP_LKS_R, OP_LKP_R };
			assert(start.RegType == ValueType->GetRegType());
			ExpEmit dest(build, start.RegType);
			if (start.RegNum <= 255)
			{
				// Since large constant tables are the exception, the constant component in C is an immediate value here.
				build->Emit(LKR_Ops[start.RegType], dest.RegNum, indexv.RegNum, start.RegNum);
			}
			else
			{
				build->Emit(OP_ADD_RK, indexv.RegNum, indexv.RegNum, build->GetConstantInt(start.RegNum));
				build->Emit(LKR_Ops[start.RegType], dest.RegNum, indexv.RegNum, 0);
			}
			indexv.Free(build);
			return dest;
		}
	}
}

//==========================================================================
//
// Checks if a function may be called from the current context.
//
//==========================================================================

static bool CheckFunctionCompatiblity(FScriptPosition &ScriptPosition, PFunction *caller, PFunction *callee)
{
	if (callee->Variants[0].Flags & VARF_Method)
	{
		// The called function must support all usage modes of the current function. It may support more, but must not support less.
		if ((callee->Variants[0].UseFlags & caller->Variants[0].UseFlags) != caller->Variants[0].UseFlags)
		{
			ScriptPosition.Message(MSG_ERROR, "Function %s incompatible with current context\n", callee->SymbolName.GetChars());
			return false;
		}

		if (!(caller->Variants[0].Flags & VARF_Method))
		{
			ScriptPosition.Message(MSG_ERROR, "Call to non-static function %s from a static context", callee->SymbolName.GetChars());
			return false;
		}
		else
		{
			auto callingself = caller->Variants[0].SelfClass;
			auto calledself = callee->Variants[0].SelfClass;
			bool match = (callingself == calledself);
			if (!match)
			{
				auto callingselfcls = PType::toClass(caller->Variants[0].SelfClass);
				auto calledselfcls = PType::toClass(callee->Variants[0].SelfClass);
				match = callingselfcls != nullptr && calledselfcls != nullptr && callingselfcls->Descriptor->IsDescendantOf(calledselfcls->Descriptor);
			}

			if (!match)
			{
				ScriptPosition.Message(MSG_ERROR, "Call to member function %s with incompatible self pointer.", callee->SymbolName.GetChars());
				return false;
			}
		}
	}
	return true;
}

//==========================================================================
//
//
//
//==========================================================================

FxFunctionCall::FxFunctionCall(FName methodname, FName rngname, FArgumentList &args, const FScriptPosition &pos)
: FxExpression(EFX_FunctionCall, pos)
{
	MethodName = methodname;
	RNG = &pr_exrandom;
	ArgList = std::move(args);
	if (rngname != NAME_None)
	{
		switch (MethodName)
		{
		case NAME_Random:
		case NAME_FRandom:
		case NAME_RandomPick:
		case NAME_FRandomPick:
		case NAME_Random2:
		case NAME_SetRandomSeed:
			RNG = FRandom::StaticFindRNG(rngname.GetChars());
			break;

		default:
			pos.Message(MSG_ERROR, "Cannot use named RNGs with %s", MethodName.GetChars());
			break;

		}
	}
}

//==========================================================================
//
//
//
//==========================================================================

FxFunctionCall::~FxFunctionCall()
{
}

//==========================================================================
//
// Check function that gets called
//
//==========================================================================

static bool CheckArgSize(FName fname, FArgumentList &args, int min, int max, FScriptPosition &sc)
{
	int s = args.Size();
	if (s < min)
	{
		sc.Message(MSG_ERROR, "Insufficient arguments in call to %s, expected %d, got %d", fname.GetChars(), min, s);
		return false;
	}
	else if (s > max && max >= 0)
	{
		sc.Message(MSG_ERROR, "Too many arguments in call to %s, expected %d, got %d", fname.GetChars(), min, s);
		return false;
	}
	return true;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxFunctionCall::Resolve(FCompileContext& ctx)
{
	bool error = false;

	for (auto a : ArgList)
	{
		if (a == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Empty function argument.");
			delete this;
			return nullptr;
		}
	}

	if (ctx.Class != nullptr)
	{
		PFunction *afd = FindClassMemberFunction(ctx.Class, ctx.Class, MethodName, ScriptPosition, &error, ctx.Version);

		if (afd != nullptr)
		{
			if (ctx.Function == nullptr)
			{
				ScriptPosition.Message(MSG_ERROR, "Unable to call function %s from constant declaration", MethodName.GetChars());
				delete this;
				return nullptr;
			}

			// [ZZ] validate call
			int outerflags = 0;
			if (ctx.Function)
			{
				outerflags = ctx.Function->Variants[0].Flags;
				if (((outerflags & (VARF_VirtualScope | VARF_Virtual)) == (VARF_VirtualScope | VARF_Virtual)) && ctx.Class)
					outerflags = FScopeBarrier::FlagsFromSide(FScopeBarrier::SideFromObjectFlags(ctx.Class->ScopeFlags));
			}
			int innerflags = afd->Variants[0].Flags;
			int innerside = FScopeBarrier::SideFromFlags(innerflags);
			// [ZZ] check this at compile time. this would work for most legit cases.
			if (innerside == FScopeBarrier::Side_Virtual)
			{
				innerside = FScopeBarrier::SideFromObjectFlags(ctx.Class->ScopeFlags);
				innerflags = FScopeBarrier::FlagsFromSide(innerside);
			}
			FScopeBarrier scopeBarrier(outerflags, innerflags, MethodName.GetChars());
			if (!scopeBarrier.callable)
			{
				ScriptPosition.Message(MSG_ERROR, "%s", scopeBarrier.callerror.GetChars());
				delete this;
				return nullptr;
			}

			// [ZZ] this is only checked for VARF_Methods in the other place. bug?
			if (!CheckFunctionCompatiblity(ScriptPosition, ctx.Function, afd))
			{
				delete this;
				return nullptr;
			}

			auto self = (afd->Variants[0].Flags & VARF_Method) ? new FxSelf(ScriptPosition) : nullptr;
			auto x = new FxVMFunctionCall(self, afd, ArgList, ScriptPosition, false);
			delete this;
			return x->Resolve(ctx);
		}
	}

	for (size_t i = 0; i < countof(FxFlops); ++i)
	{
		if (MethodName == FxFlops[i].Name)
		{
			FxExpression *x = new FxFlopFunctionCall(i, ArgList, ScriptPosition);
			delete this;
			return x->Resolve(ctx);
		}
	}

	int min, max, special;
	if (MethodName == NAME_ACS_NamedExecuteWithResult || MethodName == NAME_CallACS)
	{
		special = -ACS_ExecuteWithResult;
		min = 1;
		max = 5;
	}
	else
	{
		// This alias is needed because Actor has a Teleport function.
		if (MethodName == NAME_TeleportSpecial) MethodName = NAME_Teleport;
		special = P_FindLineSpecial(MethodName.GetChars(), &min, &max);
	}
	if (special != 0 && min >= 0)
	{
		int paramcount = ArgList.Size();
		if (ctx.Function == nullptr || ctx.Class == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Unable to call action special %s from constant declaration", MethodName.GetChars());
			delete this;
			return nullptr;
		}
		else if (paramcount < min)
		{
			ScriptPosition.Message(MSG_ERROR, "Not enough parameters for '%s' (expected %d, got %d)", 
				MethodName.GetChars(), min, paramcount);
			delete this;
			return nullptr;
		}
		else if (paramcount > max)
		{
			ScriptPosition.Message(MSG_ERROR, "too many parameters for '%s' (expected %d, got %d)", 
				MethodName.GetChars(), max, paramcount);
			delete this;
			return nullptr;
		}
		FxExpression *self = (ctx.Function && (ctx.Function->Variants[0].Flags & VARF_Method) && isActor(ctx.Class)) ? new FxSelf(ScriptPosition) : (FxExpression*)new FxConstant(ScriptPosition);
		FxExpression *x = new FxActionSpecialCall(self, special, ArgList, ScriptPosition);
		delete this;
		return x->Resolve(ctx);
	}

	PClass *cls = FindClassType(MethodName, ctx);
	if (cls != nullptr)
	{
		if (CheckArgSize(MethodName, ArgList, 1, 1, ScriptPosition))
		{
			FxExpression *x = new FxDynamicCast(cls, ArgList[0]);
			ArgList[0] = nullptr;
			delete this;
			return x->Resolve(ctx);
		}
		else
		{
			delete this;
			return nullptr;
		}
	}


	// Last but not least: Check builtins and type casts. The random functions can take a named RNG if specified.
	// Note that for all builtins the used arguments have to be nulled in the ArgList so that they won't get deleted before they get used.
	FxExpression *func = nullptr;

	switch (MethodName)
	{
	case NAME_Color:
		if (ArgList.Size() == 3 || ArgList.Size() == 4)
		{
			func = new FxColorLiteral(ArgList, ScriptPosition);
			break;
		}
		// fall through
	case NAME_Bool:
	case NAME_Int:
	case NAME_uInt:
	case NAME_Float:
	case NAME_Double:
	case NAME_Name:
	case NAME_Sound:
	case NAME_State:
	case NAME_SpriteID:
	case NAME_TextureID:
		if (CheckArgSize(MethodName, ArgList, 1, 1, ScriptPosition))
		{
			PType *type = 
				MethodName == NAME_Bool ? TypeBool :
				MethodName == NAME_Int ? TypeSInt32 :
				MethodName == NAME_uInt ? TypeUInt32 :
				MethodName == NAME_Float ? TypeFloat64 :
				MethodName == NAME_Double ? TypeFloat64 :
				MethodName == NAME_Name ? TypeName :
				MethodName == NAME_SpriteID ? TypeSpriteID :
				MethodName == NAME_TextureID ? TypeTextureID :
				MethodName == NAME_State ? TypeState :
				MethodName == NAME_Color ? TypeColor : (PType*)TypeSound;

			func = new FxTypeCast(ArgList[0], type, true, true);
			ArgList[0] = nullptr;
		}
		break;

	case NAME_GetClass:
		if (CheckArgSize(NAME_GetClass, ArgList, 0, 0, ScriptPosition))
		{
			func = new FxGetClass(new FxSelf(ScriptPosition));
		}
		break;

	case NAME_GetParentClass:
		if (CheckArgSize(NAME_GetParentClass, ArgList, 0, 0, ScriptPosition))
		{
			func = new FxGetParentClass(new FxSelf(ScriptPosition));
		}
		break;

	case NAME_GetClassName:
		if (CheckArgSize(NAME_GetClassName, ArgList, 0, 0, ScriptPosition))
		{
			func = new FxGetClassName(new FxSelf(ScriptPosition));
		}
		break;

	case NAME_GetDefaultByType:
		if (CheckArgSize(NAME_GetDefaultByType, ArgList, 1, 1, ScriptPosition))
		{
			func = new FxGetDefaultByType(ArgList[0]);
			ArgList[0] = nullptr;
		}
		break;

	case NAME_SetRandomSeed:
		if (CheckArgSize(NAME_Random, ArgList, 1, 1, ScriptPosition))
		{
			func = new FxRandomSeed(RNG, ArgList[0], ScriptPosition, ctx.FromDecorate);
			ArgList[0] = nullptr;
		}
		break;

	case NAME_Random:
		// allow calling Random without arguments to default to (0, 255)
		if (ArgList.Size() == 0)
		{
			func = new FxRandom(RNG, new FxConstant(0, ScriptPosition), new FxConstant(255, ScriptPosition), ScriptPosition, ctx.FromDecorate);
		}
		else if (CheckArgSize(NAME_Random, ArgList, 2, 2, ScriptPosition))
		{
			func = new FxRandom(RNG, ArgList[0], ArgList[1], ScriptPosition, ctx.FromDecorate);
			ArgList[0] = ArgList[1] = nullptr;
		}
		break;

	case NAME_FRandom:
		if (CheckArgSize(NAME_FRandom, ArgList, 2, 2, ScriptPosition))
		{
			func = new FxFRandom(RNG, ArgList[0], ArgList[1], ScriptPosition);
			ArgList[0] = ArgList[1] = nullptr;
		}
		break;

	case NAME_RandomPick:
	case NAME_FRandomPick:
		if (CheckArgSize(MethodName, ArgList, 1, -1, ScriptPosition))
		{
			func = new FxRandomPick(RNG, ArgList, MethodName == NAME_FRandomPick, ScriptPosition, ctx.FromDecorate);
		}
		break;

	case NAME_Random2:
		if (CheckArgSize(NAME_Random2, ArgList, 0, 1, ScriptPosition))
		{
			func = new FxRandom2(RNG, ArgList.Size() == 0? nullptr : ArgList[0], ScriptPosition, ctx.FromDecorate);
			if (ArgList.Size() > 0) ArgList[0] = nullptr;
		}
		break;

	case NAME_Min:
	case NAME_Max:
		if (CheckArgSize(MethodName, ArgList, 2, -1, ScriptPosition))
		{
			func = new FxMinMax(ArgList, MethodName, ScriptPosition);
		}
		break;

	case NAME_Clamp:
		if (CheckArgSize(MethodName, ArgList, 3, 3, ScriptPosition))
		{
			TArray<FxExpression *> pass;
			pass.Resize(2);
			pass[0] = ArgList[0];
			pass[1] = ArgList[1];
			pass[0] = new FxMinMax(pass, NAME_Max, ScriptPosition);
			pass[1] = ArgList[2];
			func = new FxMinMax(pass, NAME_Min, ScriptPosition);
			ArgList[0] = ArgList[1] = ArgList[2] = nullptr;
		}
		break;

	case NAME_Abs:
		if (CheckArgSize(MethodName, ArgList, 1, 1, ScriptPosition))
		{
			func = new FxAbs(ArgList[0]);
			ArgList[0] = nullptr;
		}
		break;

	case NAME_ATan2:
	case NAME_VectorAngle:
		if (CheckArgSize(MethodName, ArgList, 2, 2, ScriptPosition))
		{
			func = MethodName == NAME_ATan2 ? new FxATan2(ArgList[0], ArgList[1], ScriptPosition) : new FxATan2(ArgList[1], ArgList[0], ScriptPosition);
			ArgList[0] = ArgList[1] = nullptr;
		}
		break;

	case NAME_New:
		if (CheckArgSize(MethodName, ArgList, 0, 1, ScriptPosition))
		{
			// [ZZ] allow implicit new() call to mean "create current class instance"
			if (!ArgList.Size() && !ctx.Class->isClass())
			{
				ScriptPosition.Message(MSG_ERROR, "Cannot use implicit new() in a struct");
				delete this;
				return nullptr;
			}
			else if (!ArgList.Size())
			{
				auto cls = static_cast<PClassType*>(ctx.Class)->Descriptor;
				ArgList.Push(new FxConstant(cls, NewClassPointer(cls), ScriptPosition));
			}

			func = new FxNew(ArgList[0]);
			ArgList[0] = nullptr;
		}
		break;


	default:
		ScriptPosition.Message(MSG_ERROR, "Call to unknown function '%s'", MethodName.GetChars());
		break;
	}
	if (func != nullptr)
	{
		delete this;
		return func->Resolve(ctx);
	}
	delete this;
	return nullptr;
}


//==========================================================================
//
//
//
//==========================================================================

FxMemberFunctionCall::FxMemberFunctionCall(FxExpression *self, FName methodname, FArgumentList &args, const FScriptPosition &pos)
	: FxExpression(EFX_MemberFunctionCall, pos)
{
	Self = self;
	MethodName = methodname;
	ArgList = std::move(args);
}

//==========================================================================
//
//
//
//==========================================================================

FxMemberFunctionCall::~FxMemberFunctionCall()
{
	SAFE_DELETE(Self);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxMemberFunctionCall::Resolve(FCompileContext& ctx)
{
	PContainerType *cls = nullptr;
	bool staticonly = false;
	bool novirtual = false;
	bool isreadonly = false;

	PContainerType *ccls = nullptr;

	if (ctx.Class == nullptr)
	{
		// There's no way that a member function call can resolve to a constant so abort right away.
		ScriptPosition.Message(MSG_ERROR, "Expression is not constant");
		delete this;
		return nullptr;
	}

	for (auto a : ArgList)
	{
		if (a == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Empty function argument");
			delete this;
			return nullptr;
		}
	}

	if (Self->ExprType == EFX_Identifier)
	{
		auto id = static_cast<FxIdentifier *>(Self)->Identifier;
		// If the left side is a class name for a static member function call it needs to be resolved manually 
		// because the resulting value type would cause problems in nearly every other place where identifiers are being used.
		// [ZZ] substitute ccls for String internal type.
		if (id == NAME_String) ccls = TypeStringStruct;
		else ccls = FindContainerType(id, ctx);
		if (ccls != nullptr) static_cast<FxIdentifier *>(Self)->noglobal = true;
	}

	SAFE_RESOLVE(Self, ctx);

	if (Self->ValueType == TypeError)
	{
		if (ccls != nullptr)
		{
			cls = ccls;
			staticonly = true;
			if (ccls->isClass())
			{
				if (ctx.Function == nullptr)
				{
					ScriptPosition.Message(MSG_ERROR, "Unable to call %s from constant declaration", MethodName.GetChars());
					delete this;
					return nullptr;
				}
				auto clstype = PType::toClass(ctx.Function->Variants[0].SelfClass);
				if (clstype != nullptr)
				{
					novirtual = clstype->Descriptor->IsDescendantOf(static_cast<PClassType*>(ccls)->Descriptor);
					if (novirtual)
					{
						bool error;
						PFunction *afd = FindClassMemberFunction(ccls, ctx.Class, MethodName, ScriptPosition, &error, ctx.Version);
						if ((nullptr != afd) && (afd->Variants[0].Flags & VARF_Method) && (afd->Variants[0].Flags & VARF_Virtual))
						{
							staticonly = false;
							novirtual = true;
							delete Self;
							Self = new FxSelf(ScriptPosition);
							Self->ValueType = NewPointer(cls);
						}
						else novirtual = false;
					}
				}
			}
			if (!novirtual) goto isresolved;
		}
	}

	if (Self->ExprType == EFX_Super)
	{
		if (ctx.Function == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Unable to call %s from constant declaration", MethodName.GetChars());
			delete this;
			return nullptr;
		}
		auto clstype = PType::toClass(ctx.Function->Variants[0].SelfClass);
		if (clstype != nullptr)
		{
			// give the node the proper value type now that we know it's properly used.
			cls = clstype->ParentType;
			Self->ValueType = NewPointer(cls);
			Self->ExprType = EFX_Self;
			novirtual = true;	// super calls are always non-virtual
		}
		else
		{
			ScriptPosition.Message(MSG_ERROR, "Super requires a class type");
		}
	}

	// Note: These builtins would better be relegated to the actual type objects, instead of polluting this file, but that's a task for later.

	// Texture builtins.
	else if (Self->ValueType == TypeTextureID)
	{
		if (MethodName == NAME_IsValid || MethodName == NAME_IsNull || MethodName == NAME_Exists || MethodName == NAME_SetInvalid || MethodName == NAME_SetNull)
		{
			if (ArgList.Size() > 0)
			{
				ScriptPosition.Message(MSG_ERROR, "Too many parameters in call to %s", MethodName.GetChars());
				delete this;
				return nullptr;
			}
			// No need to create a dedicated node here, all builtins map directly to trivial operations.
			Self->ValueType = TypeSInt32;	// all builtins treat the texture index as integer.
			FxExpression *x;
			switch (MethodName)
			{
			case NAME_IsValid:
				x = new FxCompareRel('>', Self, new FxConstant(0, ScriptPosition));
				break;

			case NAME_IsNull:
				x = new FxCompareEq(TK_Eq, Self, new FxConstant(0, ScriptPosition));
				break;

			case NAME_Exists:
				x = new FxCompareRel(TK_Geq, Self, new FxConstant(0, ScriptPosition));
				break;

			case NAME_SetInvalid:
				x = new FxAssign(Self, new FxConstant(-1, ScriptPosition));
				break;

			case NAME_SetNull:
				x = new FxAssign(Self, new FxConstant(0, ScriptPosition));
				break;
			}
			Self = nullptr;
			SAFE_RESOLVE(x, ctx);
			if (MethodName == NAME_SetInvalid || MethodName == NAME_SetNull) x->ValueType = TypeVoid; // override the default type of the assignment operator.
			delete this;
			return x;
		}
	}

	else if (Self->IsVector())
	{
		// handle builtins: Vectors got 2: Length and Unit.
		if (MethodName == NAME_Length || MethodName == NAME_Unit)
		{
			if (ArgList.Size() > 0)
			{
				ScriptPosition.Message(MSG_ERROR, "Too many parameters in call to %s", MethodName.GetChars());
				delete this;
				return nullptr;
			}
			auto x = new FxVectorBuiltin(Self, MethodName);
			Self = nullptr;
			delete this;
			return x->Resolve(ctx);
		}
	}

	else if (Self->ValueType == TypeString)
	{
		if (MethodName == NAME_Length)	// This is an intrinsic because a dedicated opcode exists for it.
		{
			auto x = new FxStrLen(Self);
			Self = nullptr;
			delete this;
			return x->Resolve(ctx);
		}
		// same for String methods. It also uses a hidden struct type to define them.
		Self->ValueType = TypeStringStruct;
	}
	else if (Self->IsDynamicArray())
	{
		if (MethodName == NAME_Size)
		{
			FxExpression *x = new FxMemberIdentifier(Self, NAME_Size, ScriptPosition);	// todo: obfuscate the name to prevent direct access.
			Self->ValueType = static_cast<PDynArray*>(Self->ValueType)->BackingType;
			Self = nullptr;
			delete this;
			return x->Resolve(ctx);
		}
		else
		{
			auto elementType = static_cast<PDynArray*>(Self->ValueType)->ElementType;
			Self->ValueType = static_cast<PDynArray*>(Self->ValueType)->BackingType;
			bool isDynArrayObj = elementType->isObjectPointer();
			// this requires some added type checks for the passed types.
			int idx = 0;
			for (auto &a : ArgList)
			{
				a = a->Resolve(ctx);
				if (a == nullptr)
				{
					delete this;
					return nullptr;
				}
				if (isDynArrayObj && ((MethodName == NAME_Push && idx == 0) || (MethodName == NAME_Insert && idx == 1)))
				{
					// Null pointers are always valid.
					if (!a->isConstant() || static_cast<FxConstant*>(a)->GetValue().GetPointer() != nullptr)
					{
						// The DynArray_Obj declaration in dynarrays.txt doesn't support generics yet. Check the type here as if it did.
						if (!a->ValueType->isObjectPointer() ||
							!static_cast<PObjectPointer*>(elementType)->PointedClass()->IsAncestorOf(static_cast<PObjectPointer*>(a->ValueType)->PointedClass()))
						{
							ScriptPosition.Message(MSG_ERROR, "Type mismatch in function argument");
							delete this;
							return nullptr;
						}
					}
				}
				if (a->IsDynamicArray())
				{
					// Copy and Move must turn their parameter into a pointer to the backing struct type.
					auto backingtype = static_cast<PDynArray*>(a->ValueType)->BackingType;
					if (elementType != static_cast<PDynArray*>(a->ValueType)->ElementType)
					{
						ScriptPosition.Message(MSG_ERROR, "Type mismatch in function argument");
						delete this;
						return nullptr;
					}
					bool writable;
					if (!a->RequestAddress(ctx, &writable))
					{
						ScriptPosition.Message(MSG_ERROR, "Unable to dereference array variable");
						delete this;
						return nullptr;
					}
					a->ValueType = NewPointer(backingtype);

					// Also change the field's type so the code generator can work with this (actually this requires swapping out the entire field.)
					if (Self->ExprType == EFX_StructMember || Self->ExprType == EFX_ClassMember || Self->ExprType == EFX_StackVariable)
					{
						auto member = static_cast<FxMemberBase*>(Self);
						auto newfield = Create<PField>(NAME_None, backingtype, 0, member->membervar->Offset);
						member->membervar = newfield;
					}
				}
				else if (a->IsPointer() && Self->ValueType->isPointer())
				{
					// the only case which must be checked up front is for pointer arrays receiving a new element.
					// Since there is only one native backing class it uses a neutral void pointer as its argument,
					// meaning that FxMemberFunctionCall is unable to do a proper check. So we have to do it here.
					if (a->ValueType != elementType)
					{
						ScriptPosition.Message(MSG_ERROR, "Type mismatch in function argument. Got %s, expected %s", a->ValueType->DescriptiveName(), elementType->DescriptiveName());
						delete this;
						return nullptr;
					}
				}
				idx++;
			}
		}
	}
	else if (Self->IsArray())
	{
		if (MethodName == NAME_Size)
		{
			if (ArgList.Size() > 0)
			{
				ScriptPosition.Message(MSG_ERROR, "Too many parameters in call to %s", MethodName.GetChars());
				delete this;
				return nullptr;
			}
			if (!Self->isStaticArray())
			{
				auto atype = Self->ValueType;
				if (Self->ValueType->isPointer()) atype = ValueType->toPointer()->PointedType;
				auto size = static_cast<PArray*>(atype)->ElementCount;
				auto x = new FxConstant(size, ScriptPosition);
				delete this;
				return x;
			}
			else
			{
				// Resizable arrays can only be defined in C code and they can only exist in pointer form to reduce their impact on the code generator.
				if (Self->ExprType == EFX_StructMember || Self->ExprType == EFX_ClassMember || Self->ExprType == EFX_GlobalVariable)
				{
					auto member = static_cast<FxMemberBase*>(Self);
					auto newfield = Create<PField>(NAME_None, TypeUInt32, VARF_ReadOnly, member->membervar->Offset + sizeof(void*));	// the size is stored right behind the pointer.
					member->membervar = newfield;
					Self = nullptr;
					delete this;
					member->ValueType = TypeUInt32;
					return member;
				}
				else
				{
					// This should never happen because resizable arrays cannot be defined in scripts.
					ScriptPosition.Message(MSG_ERROR, "Cannot retrieve size of array");
					delete this;
					return nullptr;
				}
			}
		}
	}


	if (MethodName == NAME_GetParentClass &&
		(Self->IsObject() || Self->ValueType->isClassPointer()))
	{
		if (CheckArgSize(NAME_GetParentClass, ArgList, 0, 0, ScriptPosition))
		{
			auto x = new FxGetParentClass(Self);
			return x->Resolve(ctx);
		}
	}
	if (MethodName == NAME_GetClassName &&
		(Self->IsObject() || Self->ValueType->isClassPointer()))
	{
		if (CheckArgSize(NAME_GetClassName, ArgList, 0, 0, ScriptPosition))
		{
			auto x = new FxGetClassName(Self);
			return x->Resolve(ctx);
		}
	}

	if (Self->ValueType->isRealPointer())
	{
		auto ptype = Self->ValueType->toPointer()->PointedType;
		cls = ptype->toContainer();
		if (cls != nullptr)
		{
			if (ptype->isClass() && MethodName == NAME_GetClass)
			{
				if (ArgList.Size() > 0)
				{
					ScriptPosition.Message(MSG_ERROR, "Too many parameters in call to %s", MethodName.GetChars());
					delete this;
					return nullptr;
				}
				auto x = new FxGetClass(Self);
				return x->Resolve(ctx);
			}
		}
		else
		{
			ScriptPosition.Message(MSG_ERROR, "Left hand side of %s must point to a class object", MethodName.GetChars());
			delete this;
			return nullptr;
		}
	}
	else if (Self->ValueType->isStruct())
	{
		bool writable;

		// [ZZ] allow const method to be called on a readonly struct
		isreadonly = !(Self->RequestAddress(ctx, &writable) && writable);
		cls = static_cast<PStruct*>(Self->ValueType);
		Self->ValueType = NewPointer(Self->ValueType);
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "Invalid expression on left hand side of %s", MethodName.GetChars());
		delete this;
		return nullptr;
	}

	// Todo: handle member calls from instantiated structs.

isresolved:
	bool error = false;
	PFunction *afd = FindClassMemberFunction(cls, ctx.Class, MethodName, ScriptPosition, &error, ctx.Version);
	if (error)
	{
		delete this;
		return nullptr;
	}

	if (afd == nullptr)
	{
		ScriptPosition.Message(MSG_ERROR, "Unknown function %s", MethodName.GetChars());
		delete this;
		return nullptr;
	}

	if (isreadonly && !(afd->Variants[0].Flags & VARF_ReadOnly))
	{
		// Cannot be made writable so we cannot use its methods.
		// [ZZ] Why this esoteric message?
		ScriptPosition.Message(MSG_ERROR, "Readonly struct on left hand side of %s not allowed", MethodName.GetChars());
		delete this;
		return nullptr;
	}

	// [ZZ] if self is a struct or a class member, check if it's valid to call this function at all.
	//		implement more magic
	int outerflags = 0;
	if (ctx.Function)
	{
		outerflags = ctx.Function->Variants[0].Flags;
		if (((outerflags & (VARF_VirtualScope | VARF_Virtual)) == (VARF_VirtualScope | VARF_Virtual)) && ctx.Class)
			outerflags = FScopeBarrier::FlagsFromSide(FScopeBarrier::SideFromObjectFlags(ctx.Class->ScopeFlags));
	}
	int innerflags = afd->Variants[0].Flags;
	int innerside = FScopeBarrier::SideFromFlags(innerflags);
	// [ZZ] check this at compile time. this would work for most legit cases.
	if (innerside == FScopeBarrier::Side_Virtual)
	{
		innerside = FScopeBarrier::SideFromObjectFlags(cls->ScopeFlags);
		innerflags = FScopeBarrier::FlagsFromSide(innerside);
	}
	else if (innerside != FScopeBarrier::Side_Clear)
	{
		if (Self->ExprType == EFX_StructMember)
		{
			FxStructMember* pmember = (FxStructMember*)Self;
			if (innerside == FScopeBarrier::Side_PlainData)
				innerflags = FScopeBarrier::ChangeSideInFlags(innerflags, pmember->BarrierSide);
		}
	}
	FScopeBarrier scopeBarrier(outerflags, innerflags, MethodName.GetChars());
	if (!scopeBarrier.callable)
	{
		ScriptPosition.Message(MSG_ERROR, "%s", scopeBarrier.callerror.GetChars());
		delete this;
		return nullptr;
	}

	if (staticonly && (afd->Variants[0].Flags & VARF_Method))
	{
		if (!novirtual || !(afd->Variants[0].Flags & VARF_Virtual))
		{
			auto clstype = PType::toClass(ctx.Class);
			auto ccls = PType::toClass(cls);
			if (clstype == nullptr || ccls == nullptr || !clstype->Descriptor->IsDescendantOf(ccls->Descriptor))
			{
				ScriptPosition.Message(MSG_ERROR, "Cannot call non-static function %s::%s from here", cls->TypeName.GetChars(), MethodName.GetChars());
				delete this;
				return nullptr;
			}
			else
			{
				// Todo: If this is a qualified call to a parent class function, let it through (but this needs to disable virtual calls later.)
				ScriptPosition.Message(MSG_ERROR, "Qualified member call to parent class %s::%s is not yet implemented", cls->TypeName.GetChars(), MethodName.GetChars());
				delete this;
				return nullptr;
			}
		}
	}

	if (afd->Variants[0].Flags & VARF_Method)
	{
		if (ctx.Function == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Unable to call %s from constant declaration", MethodName.GetChars());
			delete this;
			return nullptr;
		}
		if (Self->ExprType == EFX_Self)
		{
			if (!CheckFunctionCompatiblity(ScriptPosition, ctx.Function, afd))
			{
				delete this;
				return nullptr;
			}
		}
		else
		{
			// Functions with no Actor usage may not be called through a pointer because they will lose their context.
			if (!(afd->Variants[0].UseFlags & SUF_ACTOR))
			{
				ScriptPosition.Message(MSG_ERROR, "Function %s cannot be used with a non-self object", afd->SymbolName.GetChars());
				delete this;
				return nullptr;
			}
		}
	}

	// do not pass the self pointer to static functions.
	auto self = (afd->Variants[0].Flags & VARF_Method) ? Self : nullptr;
	auto x = new FxVMFunctionCall(self, afd, ArgList, ScriptPosition, staticonly|novirtual);
	if (Self == self) Self = nullptr;
	delete this;
	return x->Resolve(ctx);
}


//==========================================================================
//
// FxActionSpecialCall
//
// If special is negative, then the first argument will be treated as a
// name for ACS_NamedExecuteWithResult.
//
//==========================================================================

FxActionSpecialCall::FxActionSpecialCall(FxExpression *self, int special, FArgumentList &args, const FScriptPosition &pos)
: FxExpression(EFX_ActionSpecialCall, pos)
{
	Self = self;
	Special = special;
	ArgList = std::move(args);
	while (ArgList.Size() < 5)
	{
		ArgList.Push(new FxConstant(0, ScriptPosition));
	}
}

//==========================================================================
//
//
//
//==========================================================================

FxActionSpecialCall::~FxActionSpecialCall()
{
	SAFE_DELETE(Self);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxActionSpecialCall::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	bool failed = false;

	SAFE_RESOLVE_OPT(Self, ctx);
	for (unsigned i = 0; i < ArgList.Size(); i++)
	{
		ArgList[i] = ArgList[i]->Resolve(ctx);
		if (ArgList[i] == nullptr)
		{
			failed = true;
		}
		else if (Special < 0 && i == 0)
		{
			if (ArgList[i]->ValueType == TypeString)
			{
				ArgList[i] = new FxNameCast(ArgList[i]);
				ArgList[i] = ArgList[i]->Resolve(ctx);
				if (ArgList[i] == nullptr)
				{
					failed = true;
				}
			}
			else if (ArgList[i]->ValueType != TypeName)
			{
				ScriptPosition.Message(MSG_ERROR, "Name expected for parameter %d", i);
				failed = true;
			}
		}
		else if (!ArgList[i]->IsInteger())
		{
			if (ArgList[i]->ValueType->GetRegType() == REGT_FLOAT /* lax */)
			{
				ArgList[i] = new FxIntCast(ArgList[i], ctx.FromDecorate);
				ArgList[i] = ArgList[i]->Resolve(ctx);
				if (ArgList[i] == nullptr)
				{
					delete this;
					return nullptr;
				}
			}
			else
			{
				ScriptPosition.Message(MSG_ERROR, "Integer expected for parameter %d", i);
				failed = true;
			}
		}
	}


	if (failed)
	{
		delete this;
		return nullptr;
	}
	ValueType = TypeSInt32;
	return this;
}


//==========================================================================
//
// 
//
//==========================================================================

int BuiltinCallLineSpecial(int special, AActor *activator, int arg1, int arg2, int arg3, int arg4, int arg5)
{
	return P_ExecuteSpecial(currentVMLevel , special, nullptr, activator, 0, arg1, arg2, arg3, arg4, arg5);
}

DEFINE_ACTION_FUNCTION_NATIVE(DObject, BuiltinCallLineSpecial, BuiltinCallLineSpecial)
{
	PARAM_PROLOGUE;
	PARAM_INT(special);
	PARAM_OBJECT(activator, AActor);
	PARAM_INT(arg1);
	PARAM_INT(arg2);
	PARAM_INT(arg3);
	PARAM_INT(arg4);
	PARAM_INT(arg5);

	ACTION_RETURN_INT(P_ExecuteSpecial(currentVMLevel, special, nullptr, activator, 0, arg1, arg2, arg3, arg4, arg5));
}

ExpEmit FxActionSpecialCall::Emit(VMFunctionBuilder *build)
{
	unsigned i = 0;

	// Call the BuiltinCallLineSpecial function to perform the desired special.
	static uint8_t reginfo[] = { REGT_INT, REGT_POINTER, REGT_INT, REGT_INT, REGT_INT, REGT_INT, REGT_INT };
	auto sym = FindBuiltinFunction(NAME_BuiltinCallLineSpecial);

	assert(sym);
	auto callfunc = sym->Variants[0].Implementation;

	FunctionCallEmitter emitters(callfunc);

	emitters.AddParameterIntConst(abs(Special));			// pass special number
	emitters.AddParameter(build, Self);


	for (; i < ArgList.Size(); ++i)
	{
		FxExpression *argex = ArgList[i];
		if (Special < 0 && i == 0)
		{
			assert(argex->ValueType == TypeName);
			assert(argex->isConstant());
			emitters.AddParameterIntConst(-static_cast<FxConstant *>(argex)->GetValue().GetName());
		}
		else
		{
			assert(argex->ValueType->GetRegType() == REGT_INT);
			if (argex->isConstant())
			{
				emitters.AddParameterIntConst(static_cast<FxConstant *>(argex)->GetValue().GetInt());
			}
			else
			{
				emitters.AddParameter(build, argex);
			}
		}
	}
	ArgList.DeleteAndClear();
	ArgList.ShrinkToFit();

	emitters.AddReturn(REGT_INT);
	return emitters.EmitCall(build);
}

//==========================================================================
//
// FxVMFunctionCall
//
//==========================================================================

FxVMFunctionCall::FxVMFunctionCall(FxExpression *self, PFunction *func, FArgumentList &args, const FScriptPosition &pos, bool novirtual)
: FxExpression(EFX_VMFunctionCall, pos)
{
	Self = self;
	Function = func;
	ArgList = std::move(args);
	NoVirtual = novirtual;
	CallingFunction = nullptr;
}

//==========================================================================
//
//
//
//==========================================================================

FxVMFunctionCall::~FxVMFunctionCall()
{
}

//==========================================================================
//
//
//
//==========================================================================

PPrototype *FxVMFunctionCall::ReturnProto()
{
	if (hasStringArgs) 
		return FxExpression::ReturnProto();

	return Function->Variants[0].Proto;
}


bool FxVMFunctionCall::CheckAccessibility(const VersionInfo &ver)
{
	if (Function->mVersion > ver && !(Function->Variants[0].Flags & VARF_Deprecated))
	{
		FString VersionString;
		if (ver >= MakeVersion(2, 3))
		{
			VersionString.Format("ZScript version %d.%d.%d", ver.major, ver.minor, ver.revision);
		}
		else
		{
			VersionString = "DECORATE";
		}
		ScriptPosition.Message(MSG_ERROR, "%s not accessible to %s", Function->SymbolName.GetChars(), VersionString.GetChars());
		return false;
	}
	if ((Function->Variants[0].Flags & VARF_Deprecated))
	{
		if (Function->mVersion <= ver)
		{
			ScriptPosition.Message(MSG_WARNING, "Accessing deprecated function %s - deprecated since %d.%d.%d", Function->SymbolName.GetChars(), Function->mVersion.major, Function->mVersion.minor, Function->mVersion.revision);
		}
	}
	return true;
}
//==========================================================================
//
//
//
//==========================================================================

VMFunction *FxVMFunctionCall::GetDirectFunction(PFunction *callingfunc, const VersionInfo &ver)
{
	// If this return statement calls a non-virtual function with no arguments,
	// then it can be a "direct" function. That is, the DECORATE
	// definition can call that function directly without wrapping
	// it inside VM code.

	if (ArgList.Size() == 0 && !(Function->Variants[0].Flags & VARF_Virtual) && CheckAccessibility(ver) && CheckFunctionCompatiblity(ScriptPosition, callingfunc, Function))
	{
		unsigned imp = Function->GetImplicitArgs();
		if (Function->Variants[0].ArgFlags.Size() > imp && !(Function->Variants[0].ArgFlags[imp] & VARF_Optional)) return nullptr;
		return Function->Variants[0].Implementation;
	}
	
	return nullptr;
}

//==========================================================================
//
// FxVMFunctionCall :: UnravelVarArgAJump
//
// Converts A_Jump(chance, a, b, c, d) -> A_Jump(chance, RandomPick[cajump](a, b, c, d))
// so that varargs are restricted to either text formatting or graphics drawing.
//
//==========================================================================
extern FRandom pr_cajump;

bool FxVMFunctionCall::UnravelVarArgAJump(FCompileContext &ctx)
{
	FArgumentList rplist;

	for (unsigned i = 1; i < ArgList.Size(); i++)
	{
		// This needs a bit of casting voodoo because RandomPick wants integer parameters.
		auto x = new FxIntCast(new FxTypeCast(ArgList[i], TypeStateLabel, true, true), true, true);
		rplist.Push(x->Resolve(ctx));
		ArgList[i] = nullptr;
		if (rplist[i - 1] == nullptr)
		{
			return false;
		}
	}
	FxExpression *x = new FxRandomPick(&pr_cajump, rplist, false, ScriptPosition, true);
	x = x->Resolve(ctx);
	// This cannot be done with a cast because that interprets the value as an index.
	// All we want here is to take the literal value and change its type.
	if (x) x->ValueType = TypeStateLabel;	
	ArgList[1] = x;
	ArgList.Clamp(2);
	return x != nullptr;
}

//==========================================================================
//
// FxVMFunctionCall :: Resolve
//
//==========================================================================

FxExpression *FxVMFunctionCall::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE_OPT(Self, ctx);
	bool failed = false;
	auto proto = Function->Variants[0].Proto;
	auto &argtypes = proto->ArgumentTypes;
	auto &argnames = Function->Variants[0].ArgNames;
	auto &argflags = Function->Variants[0].ArgFlags;
	auto &defaults = Function->Variants[0].Implementation->DefaultArgs;

	int implicit = Function->GetImplicitArgs();

	if (!CheckAccessibility(ctx.Version))
	{
		delete this;
		return nullptr;
	}
	// This should never happen.
	if (Self == nullptr && (Function->Variants[0].Flags & VARF_Method))
	{
		ScriptPosition.Message(MSG_ERROR, "Call to non-static function without a self pointer");
		delete this;
		return nullptr;
	}

	// Unfortunately the PrintableName is the only safe thing to catch this special case here.
	if (Function->Variants[0].Implementation->PrintableName.CompareNoCase("Actor.A_Jump [Native]") == 0)
	{
		// Unravel the varargs part of this function here so that the VM->native interface does not have to deal with it anymore.
		if (ArgList.Size() > 2)
		{
			auto ret = UnravelVarArgAJump(ctx);
			if (!ret)
			{
				return nullptr;
			}
		}
	}

	CallingFunction = ctx.Function;
	if (ArgList.Size() > 0)
	{
		if (argtypes.Size() == 0)
		{
			ScriptPosition.Message(MSG_ERROR, "Too many arguments in call to %s", Function->SymbolName.GetChars());
			delete this;
			return nullptr;
		}
		
		bool foundvarargs = false;
		PType * type = nullptr;
		int flag = 0;
		if (argtypes.Size() > 0 && argtypes.Last() != nullptr && ArgList.Size() + implicit > argtypes.Size())
		{
			ScriptPosition.Message(MSG_ERROR, "Too many arguments in call to %s", Function->SymbolName.GetChars());
			delete this;
			return nullptr;
		}

		for (unsigned i = 0; i < ArgList.Size(); i++)
		{
			// Varargs must all have the same type as the last typed argument. A_Jump is the only function using it.
			// [ZZ] Varargs MAY have arbitrary types if the method is marked vararg.
			if (!foundvarargs)
			{
				if (argtypes[i + implicit] == nullptr) foundvarargs = true;
				else
				{
					type = argtypes[i + implicit];
					flag = argflags[i + implicit];
				}
			}
			assert(type != nullptr);

			if (ArgList[i]->ExprType == EFX_NamedNode)
			{
				if (!(flag & VARF_Optional))
				{
					ScriptPosition.Message(MSG_ERROR, "Cannot use a named argument here - not all required arguments have been passed.");
					delete this;
					return nullptr;
				}
				if (foundvarargs)
				{
					ScriptPosition.Message(MSG_ERROR, "Cannot use a named argument in the varargs part of the parameter list.");
					delete this;
					return nullptr;
				}
				unsigned j;
				bool done = false;
				FName name = static_cast<FxNamedNode *>(ArgList[i])->name;
				for (j = 0; j < argnames.Size() - implicit; j++)
				{
					if (argnames[j + implicit] == name)
					{
						if (j < i)
						{
							ScriptPosition.Message(MSG_ERROR, "Named argument %s comes before current position in argument list.", name.GetChars());
							delete this;
							return nullptr;
						}
						// copy the original argument into the list
						auto old = static_cast<FxNamedNode *>(ArgList[i]);
						ArgList[i] = old->value; 
						old->value = nullptr;
						delete old;
						// now fill the gap with constants created from the default list so that we got a full list of arguments.
						int insert = j - i;
						int skipdefs = 0;
						// Defaults contain multiple entries for pointers so we need to calculate how much additional defaults we need to skip
						for (unsigned k = 0; k < i + implicit; k++)
						{
							skipdefs += argtypes[k]->GetRegCount() - 1;
						}
						for (int k = 0; k < insert; k++)
						{
							auto ntype = argtypes[i + k + implicit];
							// If this is a reference argument, the pointer type must be undone because the code below expects the pointed type as value type.
							if (argflags[i + k + implicit] & VARF_Ref)
							{
								assert(ntype->isPointer());
								ntype = TypeNullPtr; // the default of a reference type can only be a null pointer
							}
							if (ntype->GetRegCount() == 1)
							{
								auto x = new FxConstant(ntype, defaults[i + k + skipdefs + implicit], ScriptPosition);
								ArgList.Insert(i + k, x);
							}
							else 
							{
								// Vectors need special treatment because they are not normal constants
								FxConstant *cs[3] = { nullptr };
								for (int l = 0; l < ntype->GetRegCount(); l++)
								{
									cs[l] = new FxConstant(TypeFloat64, defaults[l + i + k + skipdefs + implicit], ScriptPosition);
								}
								FxExpression *x = new FxVectorValue(cs[0], cs[1], cs[2], ScriptPosition);
								ArgList.Insert(i + k, x);
								skipdefs += ntype->GetRegCount() - 1;
							}
						}
						done = true;
						break;
					}
				}
				if (!done)
				{
					ScriptPosition.Message(MSG_ERROR, "Named argument %s not found.", name.GetChars());
					delete this;
					return nullptr;
				}
				// re-get the proper info for the inserted node.
				type = argtypes[i + implicit];
				flag = argflags[i + implicit];
			}

			FxExpression *x = nullptr;
			if (foundvarargs && (Function->Variants[0].Flags & VARF_VarArg))
			{
				// only cast implicit-string types for vararg, leave everything else as-is
				// this was outright copypasted from FxFormat
				x = ArgList[i]->Resolve(ctx);
				if (x)
				{
					if (x->ValueType == TypeName ||
						x->ValueType == TypeSound) // spriteID can be a string too.
					{
						x = new FxStringCast(x);
						x = x->Resolve(ctx);
					}
				}
			}
			else if (!(flag & (VARF_Ref|VARF_Out)))
			{
				x = new FxTypeCast(ArgList[i], type, false);
				x = x->Resolve(ctx);
			}
			else
			{
				bool writable;
				ArgList[i] = ArgList[i]->Resolve(ctx);	// must be resolved before the address is requested.
				if (ArgList[i] != nullptr && ArgList[i]->ValueType != TypeNullPtr)
				{
					if (type == ArgList[i]->ValueType && type->isRealPointer() && type->toPointer()->PointedType->isStruct())
					{
						// trying to pass a struct reference as a struct reference. This must preserve the type.
					}
					else
					{
						ArgList[i]->RequestAddress(ctx, &writable);
						if (flag & VARF_Ref)ArgList[i]->ValueType = NewPointer(ArgList[i]->ValueType);
					}

					// For a reference argument the types must match 100%.
					if (type != ArgList[i]->ValueType)
					{
						ScriptPosition.Message(MSG_ERROR, "Type mismatch in reference argument %s", Function->SymbolName.GetChars());
						x = nullptr;
					}
					else
					{
						x = ArgList[i];
					}
				}
				else x = ArgList[i];
			}
			failed |= (x == nullptr);
			ArgList[i] = x;
			if (!failed && x->ValueType == TypeString)
			{
				hasStringArgs = true;
			}
		}
		int numargs = ArgList.Size() + implicit;
		if ((unsigned)numargs < argtypes.Size() && argtypes[numargs] != nullptr)
		{
			auto flags = Function->Variants[0].ArgFlags[numargs];
			if (!(flags & VARF_Optional))
			{
				ScriptPosition.Message(MSG_ERROR, "Insufficient arguments in call to %s", Function->SymbolName.GetChars());
				delete this;
				return nullptr;
			}
		}
	}
	else
	{
		if ((unsigned)implicit < argtypes.Size() && argtypes[implicit] != nullptr)
		{
			auto flags = Function->Variants[0].ArgFlags[implicit];
			if (!(flags & VARF_Optional))
			{
				ScriptPosition.Message(MSG_ERROR, "Insufficient arguments in call to %s", Function->SymbolName.GetChars());
				delete this;
				return nullptr;
			}
		}
	}
	if (failed)
	{
		delete this;
		return nullptr;
	}
	TArray<PType *> &rets = proto->ReturnTypes;
	if (rets.Size() > 0)
	{
		ValueType = rets[0];
	}
	else
	{
		ValueType = TypeVoid;
	}
	return this;
}

//==========================================================================
//
//
//
//==========================================================================

ExpEmit FxVMFunctionCall::Emit(VMFunctionBuilder *build)
{
	assert(build->Registers[REGT_POINTER].GetMostUsed() >= build->NumImplicits);
	int count = 0;

	if (count == 1)
	{
		ExpEmit reg;
		if (CheckEmitCast(build, false, reg))
		{
			ArgList.DeleteAndClear();
			ArgList.ShrinkToFit();
			return reg;
		}
	}

	VMFunction *vmfunc = Function->Variants[0].Implementation;
	bool staticcall = ((vmfunc->VarFlags & VARF_Final) || vmfunc->VirtualIndex == ~0u || NoVirtual);

	count = 0;
	FunctionCallEmitter emitters(vmfunc);
	// Emit code to pass implied parameters
	ExpEmit selfemit;
	if (Function->Variants[0].Flags & VARF_Method)
	{
		assert(Self != nullptr);
		selfemit = Self->Emit(build);
		assert(selfemit.RegType == REGT_POINTER || selfemit.RegType == REGT_STRING || (selfemit.Fixed && selfemit.Target));

		int innerside = FScopeBarrier::SideFromFlags(Function->Variants[0].Flags);

		if (innerside == FScopeBarrier::Side_Virtual)
		{
			auto selfside = FScopeBarrier::SideFromObjectFlags(Self->ValueType->toPointer()->PointedType->ScopeFlags);

			int outerside = FScopeBarrier::SideFromFlags(CallingFunction->Variants[0].Flags);
			if (outerside == FScopeBarrier::Side_Virtual)
				outerside = FScopeBarrier::SideFromObjectFlags(CallingFunction->OwningClass->ScopeFlags);

			// [ZZ] only emit if target side cannot be checked at compile time.
			if (selfside == FScopeBarrier::Side_PlainData)
			{
				// Check the self object against the calling function's flags at run time
				build->Emit(OP_SCOPE, selfemit.RegNum, outerside + 1, build->GetConstantAddress(vmfunc));
			}
		}

		emitters.AddParameter(selfemit, (selfemit.Fixed && selfemit.Target) || selfemit.RegType == REGT_STRING);
		if (Function->Variants[0].Flags & VARF_Action)
		{
			static_assert(NAP == 3, "This code needs to be updated if NAP changes");
			if (build->NumImplicits == NAP && selfemit.RegNum == 0)	// only pass this function's stateowner and stateinfo if the subfunction is run in self's context.
			{
				emitters.AddParameterPointer(1, false);
				emitters.AddParameterPointer(2, false);
			}
			else
			{
				// pass self as stateowner, otherwise all attempts of the subfunction to retrieve a state from a name would fail.
				emitters.AddParameter(selfemit, (selfemit.Fixed && selfemit.Target) || selfemit.RegType == REGT_STRING);
				emitters.AddParameterPointerConst(nullptr);
			}
		}
	}
	else staticcall = true;
	// Emit code to pass explicit parameters
	for (unsigned i = 0; i < ArgList.Size(); ++i)
	{
		emitters.AddParameter(build, ArgList[i]);
	}
	// Complete the parameter list from the defaults.
	auto &defaults = Function->Variants[0].Implementation->DefaultArgs;
	for (unsigned i = emitters.Count(); i < defaults.Size(); i++)
	{
		switch (defaults[i].Type)
		{
		default:
		case REGT_INT:
			emitters.AddParameterIntConst(defaults[i].i);
			break;
		case REGT_FLOAT:
			emitters.AddParameterFloatConst(defaults[i].f);
			break;
		case REGT_POINTER:
			emitters.AddParameterPointerConst(defaults[i].a);
			break;
		case REGT_STRING:
			emitters.AddParameterStringConst(defaults[i].s());
			break;
		}
	}
	ArgList.DeleteAndClear();
	ArgList.ShrinkToFit();

	if (!staticcall) emitters.SetVirtualReg(selfemit.RegNum);
	int resultcount = vmfunc->Proto->ReturnTypes.Size() == 0 ? 0 : MAX(AssignCount, 1);

	assert((unsigned)resultcount <= vmfunc->Proto->ReturnTypes.Size());
	for (int i = 0; i < resultcount; i++)
	{
		emitters.AddReturn(vmfunc->Proto->ReturnTypes[i]->GetRegType(), vmfunc->Proto->ReturnTypes[i]->GetRegCount());
	}
	return emitters.EmitCall(build, resultcount > 1? &ReturnRegs : nullptr);
}

//==========================================================================
//
// If calling one of the casting kludge functions, don't bother calling the
// function; just use the parameter directly. Returns true if this was a
// kludge function, false otherwise.
//
//==========================================================================

bool FxVMFunctionCall::CheckEmitCast(VMFunctionBuilder *build, bool returnit, ExpEmit &reg)
{
	FName funcname = Function->SymbolName;
	if (funcname == NAME___decorate_internal_int__ ||
		funcname == NAME___decorate_internal_bool__ ||
		funcname == NAME___decorate_internal_float__)
	{
		FxExpression *arg = ArgList[0];
		if (returnit)
		{
			if (arg->isConstant() &&
				(funcname == NAME___decorate_internal_int__ ||
				 funcname == NAME___decorate_internal_bool__))
			{ // Use immediate version for integers in range
				build->EmitRetInt(0, true, static_cast<FxConstant *>(arg)->GetValue().Int);
			}
			else
			{
				ExpEmit where = arg->Emit(build);
				build->Emit(OP_RET, RET_FINAL, EncodeRegType(where), where.RegNum);
				where.Free(build);
			}
			reg = ExpEmit();
			reg.Final = true;
		}
		else
		{
			reg = arg->Emit(build);
		}
		return true;
	}
	return false;
}

//==========================================================================
//
//
//
//==========================================================================

FxFlopFunctionCall::FxFlopFunctionCall(size_t index, FArgumentList &args, const FScriptPosition &pos)
: FxExpression(EFX_FlopFunctionCall, pos)
{
	assert(index < countof(FxFlops) && "FLOP index out of range");
	Index = (int)index;
	ArgList = std::move(args);
}

//==========================================================================
//
//
//
//==========================================================================

FxFlopFunctionCall::~FxFlopFunctionCall()
{
}

FxExpression *FxFlopFunctionCall::Resolve(FCompileContext& ctx)
{
	CHECKRESOLVED();

	if (ArgList.Size() != 1)
	{
		ScriptPosition.Message(MSG_ERROR, "%s only has one parameter", FName(FxFlops[Index].Name).GetChars());
		delete this;
		return nullptr;
	}

	ArgList[0] = ArgList[0]->Resolve(ctx);
	if (ArgList[0] == nullptr)
	{
		delete this;
		return nullptr;
	}

	if (!ArgList[0]->IsNumeric())
	{
		ScriptPosition.Message(MSG_ERROR, "numeric value expected for parameter");
		delete this;
		return nullptr;
	}
	if (ArgList[0]->isConstant())
	{
		double v = static_cast<FxConstant *>(ArgList[0])->GetValue().GetFloat();
		v = FxFlops[Index].Evaluate(v);
		FxExpression *x = new FxConstant(v, ScriptPosition);
		delete this;
		return x;
	}
	if (ArgList[0]->ValueType->GetRegType() == REGT_INT)
	{
		ArgList[0] = new FxFloatCast(ArgList[0]);
	}
	ValueType = TypeFloat64;
	return this;
}

//==========================================================================
//
//
//==========================================================================

ExpEmit FxFlopFunctionCall::Emit(VMFunctionBuilder *build)
{
	assert(ValueType == ArgList[0]->ValueType);
	ExpEmit from = ArgList[0]->Emit(build);
	ExpEmit to;
	assert(from.Konst == 0);
	assert(ValueType->GetRegCount() == 1);
	// Do it in-place, unless a local variable
	if (from.Fixed)
	{
		to = ExpEmit(build, from.RegType);
		from.Free(build);
	}
	else
	{
		to = from;
	}

	build->Emit(OP_FLOP, to.RegNum, from.RegNum, FxFlops[Index].Flop);
	ArgList.DeleteAndClear();
	ArgList.ShrinkToFit();
	return to;
}

//==========================================================================
//
//
//==========================================================================

FxVectorBuiltin::FxVectorBuiltin(FxExpression *self, FName name)
	:FxExpression(EFX_VectorBuiltin, self->ScriptPosition), Function(name), Self(self)
{
}

FxVectorBuiltin::~FxVectorBuiltin()
{
	SAFE_DELETE(Self);
}

FxExpression *FxVectorBuiltin::Resolve(FCompileContext &ctx)
{
	SAFE_RESOLVE(Self, ctx);
	assert(Self->IsVector());	// should never be created for anything else.
	ValueType = Function == NAME_Length ? TypeFloat64 : Self->ValueType;
	return this;
}

ExpEmit FxVectorBuiltin::Emit(VMFunctionBuilder *build)
{
	ExpEmit to(build, ValueType->GetRegType(), ValueType->GetRegCount());
	ExpEmit op = Self->Emit(build);
	if (Function == NAME_Length)
	{
		build->Emit(Self->ValueType == TypeVector2 ? OP_LENV2 : OP_LENV3, to.RegNum, op.RegNum);
	}
	else
	{
		ExpEmit len(build, REGT_FLOAT);
		build->Emit(Self->ValueType == TypeVector2 ? OP_LENV2 : OP_LENV3, len.RegNum, op.RegNum);
		build->Emit(Self->ValueType == TypeVector2 ? OP_DIVVF2_RR : OP_DIVVF3_RR, to.RegNum, op.RegNum, len.RegNum);
		len.Free(build);
	}
	op.Free(build);
	return to;
}

//==========================================================================
//
//
//==========================================================================

FxStrLen::FxStrLen(FxExpression *self)
	:FxExpression(EFX_StrLen, self->ScriptPosition)
{
	Self = self;
}

FxStrLen::~FxStrLen()
{
	SAFE_DELETE(Self);
}

FxExpression *FxStrLen::Resolve(FCompileContext &ctx)
{
	SAFE_RESOLVE(Self, ctx);
	assert(Self->ValueType == TypeString);
	if (Self->isConstant())
	{
		auto constself = static_cast<FxConstant *>(Self);
		auto constlen = new FxConstant((int)constself->GetValue().GetString().Len(), Self->ScriptPosition);
		delete this;
		return constlen->Resolve(ctx);
	}
	ValueType = TypeUInt32;
	return this;
}

ExpEmit FxStrLen::Emit(VMFunctionBuilder *build)
{
	ExpEmit to(build, REGT_INT);
	ExpEmit op = Self->Emit(build);
	build->Emit(OP_LENS, to.RegNum, op.RegNum);
	op.Free(build);
	return to;
}

//==========================================================================
//
//
//==========================================================================

FxGetClass::FxGetClass(FxExpression *self)
	:FxExpression(EFX_GetClass, self->ScriptPosition)
{
	Self = self;
}

FxGetClass::~FxGetClass()
{
	SAFE_DELETE(Self);
}

FxExpression *FxGetClass::Resolve(FCompileContext &ctx)
{
	SAFE_RESOLVE(Self, ctx);
	if (!Self->IsObject())
	{
		ScriptPosition.Message(MSG_ERROR, "GetClass() requires an object");
		delete this;
		return nullptr;
	}
	ValueType = NewClassPointer(static_cast<PClassType*>(Self->ValueType->toPointer()->PointedType)->Descriptor);
	return this;
}

ExpEmit FxGetClass::Emit(VMFunctionBuilder *build)
{
	ExpEmit op = Self->Emit(build);
	op.Free(build);
	ExpEmit to(build, REGT_POINTER);
	build->Emit(OP_CLSS, to.RegNum, op.RegNum);
	return to;
}

//==========================================================================
//
//
//==========================================================================

FxGetParentClass::FxGetParentClass(FxExpression *self)
	:FxExpression(EFX_GetParentClass, self->ScriptPosition)
{
	Self = self;
}

FxGetParentClass::~FxGetParentClass()
{
	SAFE_DELETE(Self);
}

FxExpression *FxGetParentClass::Resolve(FCompileContext &ctx)
{
	SAFE_RESOLVE(Self, ctx);

	if (!Self->ValueType->isClassPointer() && !Self->IsObject())
	{
		ScriptPosition.Message(MSG_ERROR, "GetParentClass() requires an object");
		delete this;
		return nullptr;
	}
	ValueType = NewClassPointer(RUNTIME_CLASS(DObject));
	return this;
}

ExpEmit FxGetParentClass::Emit(VMFunctionBuilder *build)
{
	ExpEmit op = Self->Emit(build);
	op.Free(build);
	if (Self->IsObject())
	{
		ExpEmit to(build, REGT_POINTER);
		build->Emit(OP_CLSS, to.RegNum, op.RegNum);
		op = to;
		op.Free(build);
	}
	ExpEmit to(build, REGT_POINTER);
	build->Emit(OP_LP, to.RegNum, op.RegNum, build->GetConstantInt(myoffsetof(PClass, ParentClass)));
	return to;
}

//==========================================================================
//
//
//==========================================================================

FxGetClassName::FxGetClassName(FxExpression *self)
	:FxExpression(EFX_GetClassName, self->ScriptPosition)
{
	Self = self;
}

FxGetClassName::~FxGetClassName()
{
	SAFE_DELETE(Self);
}

FxExpression *FxGetClassName::Resolve(FCompileContext &ctx)
{
	SAFE_RESOLVE(Self, ctx);

	if (!Self->ValueType->isClassPointer() && !Self->IsObject())
	{
		ScriptPosition.Message(MSG_ERROR, "GetClassName() requires an object");
		delete this;
		return nullptr;
	}
	ValueType = TypeName;
	return this;
}

ExpEmit FxGetClassName::Emit(VMFunctionBuilder *build)
{
	ExpEmit op = Self->Emit(build);
	op.Free(build);
	if (Self->IsObject())
	{
		ExpEmit to(build, REGT_POINTER);
		build->Emit(OP_CLSS, to.RegNum, op.RegNum);
		op = to;
		op.Free(build);
	}
	ExpEmit to(build, REGT_INT);
	build->Emit(OP_LW, to.RegNum, op.RegNum, build->GetConstantInt(myoffsetof(PClass, TypeName)));
	return to;
}

//==========================================================================
//
//
//==========================================================================

FxGetDefaultByType::FxGetDefaultByType(FxExpression *self)
	:FxExpression(EFX_GetDefaultByType, self->ScriptPosition)
{
	Self = self;
}

FxGetDefaultByType::~FxGetDefaultByType()
{
	SAFE_DELETE(Self);
}

FxExpression *FxGetDefaultByType::Resolve(FCompileContext &ctx)
{
	SAFE_RESOLVE(Self, ctx);
	PClass *cls = nullptr;

	if (Self->ValueType == TypeString || Self->ValueType == TypeName)
	{
		if (Self->isConstant())
		{
			cls = PClass::FindActor(static_cast<FxConstant *>(Self)->GetValue().GetName());
			if (cls == nullptr)
			{
				ScriptPosition.Message(MSG_ERROR, "GetDefaultByType() requires an actor class type, but got %s", static_cast<FxConstant *>(Self)->GetValue().GetString().GetChars());
				delete this;
				return nullptr;
			}
			Self = new FxConstant(cls, NewClassPointer(cls), ScriptPosition);
		}
		else
		{
			// this is the ugly case. We do not know what we have and cannot do proper type casting.
			// For now error out and let this case require explicit handling on the user side.
			ScriptPosition.Message(MSG_ERROR, "GetDefaultByType() requires an actor class type, but got %s", static_cast<FxConstant *>(Self)->GetValue().GetString().GetChars());
			delete this;
			return nullptr;
		}
	}
	else
	{
		auto cp = PType::toClassPointer(Self->ValueType);
		if (cp == nullptr || !cp->ClassRestriction->IsDescendantOf(RUNTIME_CLASS(AActor)))
		{
			ScriptPosition.Message(MSG_ERROR, "GetDefaultByType() requires an actor class type");
			delete this;
			return nullptr;
		}
		cls = cp->ClassRestriction;
	}
	ValueType = NewPointer(cls, true);
	return this;
}

ExpEmit FxGetDefaultByType::Emit(VMFunctionBuilder *build)
{
	ExpEmit op = Self->Emit(build);
	op.Free(build);
	ExpEmit to(build, REGT_POINTER);
	if (op.Konst)
	{
		build->Emit(OP_LKP, to.RegNum, op.RegNum);
		op = to;
	}
	build->Emit(OP_LP, to.RegNum, op.RegNum, build->GetConstantInt(myoffsetof(PClass, Defaults)));
	return to;
}

//==========================================================================
//
//
//==========================================================================

FxColorLiteral::FxColorLiteral(FArgumentList &args, FScriptPosition &sc)
	:FxExpression(EFX_ColorLiteral, sc)
{
	ArgList = std::move(args);
}

FxExpression *FxColorLiteral::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	unsigned constelements = 0;
	assert(ArgList.Size() == 3 || ArgList.Size() == 4);
	if (ArgList.Size() == 3) ArgList.Insert(0, nullptr);
	for (int i = 0; i < 4; i++)
	{
		if (ArgList[i] != nullptr)
		{
			SAFE_RESOLVE(ArgList[i], ctx);
			if (!ArgList[i]->IsInteger())
			{
				ScriptPosition.Message(MSG_ERROR, "Integer expected for color component");
				delete this;
				return nullptr;
			}
			if (ArgList[i]->isConstant())
			{
				constval += clamp(static_cast<FxConstant *>(ArgList[i])->GetValue().GetInt(), 0, 255) << (24 - i * 8);
				delete ArgList[i];
				ArgList[i] = nullptr;
				constelements++;
			}
		}
		else constelements++;
	}
	if (constelements == 4)
	{
		auto x = new FxConstant(constval, ScriptPosition);
		x->ValueType = TypeColor;
		delete this;
		return x;
	}
	ValueType = TypeColor;
	return this;
}

ExpEmit FxColorLiteral::Emit(VMFunctionBuilder *build)
{
	ExpEmit out(build, REGT_INT);
	build->Emit(OP_LK, out.RegNum, build->GetConstantInt(constval));
	for (int i = 0; i < 4; i++)
	{
		if (ArgList[i] != nullptr)
		{
			assert(!ArgList[i]->isConstant());
			ExpEmit in = ArgList[i]->Emit(build);
			in.Free(build);
			ExpEmit work(build, REGT_INT);
			build->Emit(OP_MAX_RK, work.RegNum, in.RegNum, build->GetConstantInt(0));
			build->Emit(OP_MIN_RK, work.RegNum, work.RegNum, build->GetConstantInt(255));
			if (i != 3) build->Emit(OP_SLL_RI, work.RegNum, work.RegNum, 24 - (i * 8));
			build->Emit(OP_OR_RR, out.RegNum, out.RegNum, work.RegNum);
		}
	}
	return out;
}

//==========================================================================
//
// FxSequence :: Resolve
//
//==========================================================================

FxExpression *FxSequence::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	bool fail = false;
	for (unsigned i = 0; i < Expressions.Size(); ++i)
	{
		if (nullptr == (Expressions[i] = Expressions[i]->Resolve(ctx)))
		{
			fail = true;
		}
		else if (Expressions[i]->ValueType == TypeError)
		{
			ScriptPosition.Message(MSG_ERROR, "Invalid statement");
			fail = true;
		}
	}
	if (fail)
	{
		delete this;
		return nullptr;
	}
	return this;
}

//==========================================================================
//
// FxSequence :: CheckReturn
//
//==========================================================================

bool FxSequence::CheckReturn()
{
	// a sequence always returns when its last element returns.
	return Expressions.Size() > 0 && Expressions.Last()->CheckReturn();
}

//==========================================================================
//
// FxSequence :: Emit
//
//==========================================================================

ExpEmit FxSequence::Emit(VMFunctionBuilder *build)
{
	for (unsigned i = 0; i < Expressions.Size(); ++i)
	{
		Expressions[i]->EmitStatement(build);
	}
	return ExpEmit();
}

//==========================================================================
//
// FxSequence :: GetDirectFunction
//
//==========================================================================

VMFunction *FxSequence::GetDirectFunction(PFunction *func, const VersionInfo &ver)
{
	if (Expressions.Size() == 1)
	{
		return Expressions[0]->GetDirectFunction(func, ver);
	}
	return nullptr;
}

//==========================================================================
//
// FxCompoundStatement :: Resolve
//
//==========================================================================

FxExpression *FxCompoundStatement::Resolve(FCompileContext &ctx)
{
	auto outer = ctx.Block;
	Outer = ctx.Block;
	ctx.Block = this;
	auto x = FxSequence::Resolve(ctx);
	ctx.Block = outer;
	return x;
}

//==========================================================================
//
// FxCompoundStatement :: Emit
//
//==========================================================================

ExpEmit FxCompoundStatement::Emit(VMFunctionBuilder *build)
{
	auto e = FxSequence::Emit(build);
	// Release all local variables in this block.
	for (auto l : LocalVars)
	{
		l->Release(build);
	}
	return e;
}

//==========================================================================
//
// FxCompoundStatement :: FindLocalVariable
//
// Looks for a variable name in any of the containing compound statements
// This does a simple linear search on each block's variables. 
// The lists here normally don't get large enough to justify something more complex.
//
//==========================================================================

FxLocalVariableDeclaration *FxCompoundStatement::FindLocalVariable(FName name, FCompileContext &ctx)
{
	auto block = this;
	while (block != nullptr)
	{
		for (auto l : block->LocalVars)
		{
			if (l->Name == name)
			{
				return l;
			}
		}
		block = block->Outer;
	}
	// finally check the context for function arguments
	for (auto arg : ctx.FunctionArgs)
	{
		if (arg->Name == name)
		{
			return arg;
		}
	}
	return nullptr;
}

//==========================================================================
//
// FxCompoundStatement :: CheckLocalVariable
//
// Checks if the current block already contains a local variable 
// of the given name.
//
//==========================================================================

bool FxCompoundStatement::CheckLocalVariable(FName name)
{
	for (auto l : LocalVars)
	{
		if (l->Name == name)
		{
			return true;
		}
	}
	return false;
}

//==========================================================================
//
// FxSwitchStatement
//
//==========================================================================

FxSwitchStatement::FxSwitchStatement(FxExpression *cond, FArgumentList &content, const FScriptPosition &pos)
	: FxExpression(EFX_SwitchStatement, pos)
{
	Condition = cond;
	Content = std::move(content);
}

FxSwitchStatement::~FxSwitchStatement()
{
	SAFE_DELETE(Condition);
}

FxExpression *FxSwitchStatement::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Condition, ctx);

	if (Condition->ValueType != TypeName)
	{
		Condition = new FxIntCast(Condition, false);
		SAFE_RESOLVE(Condition, ctx);
	}

	if (Content.Size() == 0)
	{
		ScriptPosition.Message(MSG_WARNING, "Empty switch statement");
		if (Condition->isConstant())
		{
			return new FxNop(ScriptPosition);
		}
		else
		{
			// The condition may have a side effect so it should be processed (possible to-do: Analyze all nodes in there and delete if not.)
			auto x = Condition;
			Condition = nullptr;
			delete this;
			x->NeedResult = false;
			return x;
		}
	}

	auto outerctrl = ctx.ControlStmt;
	ctx.ControlStmt = this;

	for (auto &line : Content)
	{
		SAFE_RESOLVE(line, ctx);
		line->NeedResult = false;
	}
	ctx.ControlStmt = outerctrl;

	if (Condition->isConstant())
	{
		ScriptPosition.Message(MSG_WARNING, "Case expression is constant");
		auto &content = Content;
		int defaultindex = -1;
		int defaultbreak = -1;
		int caseindex = -1;
		int casebreak = -1;
		// look for a case label with a matching value
		for (unsigned i = 0; i < content.Size(); i++)
		{
			if (content[i] != nullptr)
			{
				if (content[i]->ExprType == EFX_CaseStatement)
				{
					auto casestmt = static_cast<FxCaseStatement *>(content[i]);
					if (casestmt->Condition == nullptr) defaultindex = i;
					else if (casestmt->CaseValue == static_cast<FxConstant *>(Condition)->GetValue().GetInt()) caseindex = i;
					if (casestmt->Condition && casestmt->Condition->ValueType != Condition->ValueType)
					{
						casestmt->Condition->ScriptPosition.Message(MSG_ERROR, "Type mismatch in case statement");
						delete this;
						return nullptr;
					}
				}
				if (content[i]->ExprType == EFX_JumpStatement && static_cast<FxJumpStatement *>(content[i])->Token == TK_Break)
				{
					if (defaultindex >= 0 && defaultbreak < 0) defaultbreak = i;
					if (caseindex >= 0 && casebreak < 0)
					{
						casebreak = i;
						break;	// when we find this we do not need to look any further.
					}
				}
			}
		}
		if (caseindex < 0)
		{
			caseindex = defaultindex;
			casebreak = defaultbreak;
		}
		if (caseindex > 0 && casebreak - caseindex > 1)
		{
			auto seq = new FxSequence(ScriptPosition);
			for (int i = caseindex + 1; i < casebreak; i++)
			{
				if (content[i] != nullptr && content[i]->ExprType != EFX_CaseStatement)
				{
					seq->Add(content[i]);
					content[i] = nullptr;
				}
			}
			delete this;
			return seq->Resolve(ctx);
		}
		delete this;
		return new FxNop(ScriptPosition);
	}

	int mincase = INT_MAX;
	int maxcase = INT_MIN;
	for (auto line : Content)
	{
		if (line->ExprType == EFX_CaseStatement)
		{
			auto casestmt = static_cast<FxCaseStatement *>(line);
			if (casestmt->Condition != nullptr)
			{
				CaseAddr ca = { casestmt->CaseValue, 0 };
				CaseAddresses.Push(ca);
				if (ca.casevalue < mincase) mincase = ca.casevalue;
				if (ca.casevalue > maxcase) maxcase = ca.casevalue;
			}
		}
	}
	return this;
}

ExpEmit FxSwitchStatement::Emit(VMFunctionBuilder *build)
{
	assert(Condition != nullptr);
	ExpEmit emit = Condition->Emit(build);
	assert(emit.RegType == REGT_INT);
	// todo: 
	// - sort jump table by value.
	// - optimize the switch dispatcher to run in native code instead of executing each single branch instruction on its own.
	// e.g.: build->Emit(OP_SWITCH, emit.RegNum, build->GetConstantInt(CaseAddresses.Size());
	for (auto &ca : CaseAddresses)
	{
		if (ca.casevalue >= 0 && ca.casevalue <= 0xffff)
		{
			build->Emit(OP_TEST, emit.RegNum, (VM_SHALF)ca.casevalue);
		}
		else if (ca.casevalue < 0 && ca.casevalue >= -0xffff)
		{
			build->Emit(OP_TESTN, emit.RegNum, (VM_SHALF)-ca.casevalue);
		}
		else
		{
			build->Emit(OP_EQ_K, 1, emit.RegNum, build->GetConstantInt(ca.casevalue));
		}
		ca.jumpaddress = build->Emit(OP_JMP, 0);
	}
	size_t DefaultAddress = build->Emit(OP_JMP, 0);
	bool defaultset = false;

	for (auto line : Content)
	{
		switch (line->ExprType)
		{
		case EFX_CaseStatement:
			if (static_cast<FxCaseStatement *>(line)->Condition != nullptr)
			{
				for (auto &ca : CaseAddresses)
				{
					if (ca.casevalue == static_cast<FxCaseStatement *>(line)->CaseValue)
					{
						build->BackpatchToHere(ca.jumpaddress);
						break;
					}
				}
			}
			else
			{
				build->BackpatchToHere(DefaultAddress);
				defaultset = true;
			}
			break;

		default:
			line->EmitStatement(build);
			break;
		}
	}
	for (auto addr : Breaks)
	{
		build->BackpatchToHere(addr->Address);
	}
	if (!defaultset) build->BackpatchToHere(DefaultAddress);
	Content.DeleteAndClear();
	Content.ShrinkToFit();
	return ExpEmit();
}

//==========================================================================
//
// FxSequence :: CheckReturn
//
//==========================================================================

bool FxSwitchStatement::CheckReturn()
{
	bool founddefault = false;
	//A switch statement returns when it contains a no breaks, a default case, and ends with a return
	for (auto line : Content)
	{
		if (line->ExprType == EFX_JumpStatement)
		{
			return false;	// Break means that the end of the statement will be reached, Continue cannot happen in the last statement of the last block.
		}
		else if (line->ExprType == EFX_CaseStatement)
		{
			if (static_cast<FxCaseStatement*>(line)->Condition == nullptr) founddefault = true;
		}
	}
	return founddefault && Content.Size() > 0 && Content.Last()->CheckReturn();
}

//==========================================================================
//
// FxCaseStatement
//
//==========================================================================

FxCaseStatement::FxCaseStatement(FxExpression *cond, const FScriptPosition &pos)
	: FxExpression(EFX_CaseStatement, pos)
{
	Condition = cond;
}

FxCaseStatement::~FxCaseStatement()
{
	SAFE_DELETE(Condition);
}

FxExpression *FxCaseStatement::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE_OPT(Condition, ctx);

	if (Condition != nullptr)
	{
		if (!Condition->isConstant())
		{
			ScriptPosition.Message(MSG_ERROR, "Case label must be a constant value");
			delete this;
			return nullptr;
		}
		// Case labels can be ints or names.
		if (Condition->ValueType != TypeName)
		{
			Condition = new FxIntCast(Condition, false);
			SAFE_RESOLVE(Condition, ctx);
			CaseValue = static_cast<FxConstant *>(Condition)->GetValue().GetInt();
		}
		else
		{
			CaseValue = static_cast<FxConstant *>(Condition)->GetValue().GetName();
		}
	}
	return this;
}

//==========================================================================
//
// FxIfStatement
//
//==========================================================================

FxIfStatement::FxIfStatement(FxExpression *cond, FxExpression *true_part,
	FxExpression *false_part, const FScriptPosition &pos)
: FxExpression(EFX_IfStatement, pos)
{
	Condition = cond;
	WhenTrue = true_part;
	WhenFalse = false_part;
	if (WhenTrue != nullptr) WhenTrue->NeedResult = false;
	if (WhenFalse != nullptr) WhenFalse->NeedResult = false;
	assert(cond != nullptr);
}

FxIfStatement::~FxIfStatement()
{
	SAFE_DELETE(Condition);
	SAFE_DELETE(WhenTrue);
	SAFE_DELETE(WhenFalse);
}

FxExpression *FxIfStatement::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();

	if (WhenTrue == nullptr && WhenFalse == nullptr)
	{ // We don't do anything either way, so disappear
		delete this;
		ScriptPosition.Message(MSG_WARNING, "empty if statement");
		return new FxNop(ScriptPosition);
	}

	SAFE_RESOLVE(Condition, ctx);

	if (Condition->ValueType != TypeBool)
	{
		Condition = new FxBoolCast(Condition, false);
		SAFE_RESOLVE(Condition, ctx);
	}

	if (WhenTrue != nullptr)
	{
		WhenTrue = WhenTrue->Resolve(ctx);
		ABORT(WhenTrue);
	}
	if (WhenFalse != nullptr)
	{
		WhenFalse = WhenFalse->Resolve(ctx);
		ABORT(WhenFalse);
	}

	ValueType = TypeVoid;

	if (Condition->isConstant())
	{
		ExpVal condval = static_cast<FxConstant *>(Condition)->GetValue();
		bool result = condval.GetBool();

		FxExpression *e = result ? WhenTrue : WhenFalse;
		delete (result ? WhenFalse : WhenTrue);
		WhenTrue = WhenFalse = nullptr;
		if (e == nullptr) e = new FxNop(ScriptPosition);	// create a dummy if this statement gets completely removed by optimizing out the constant parts.
		delete this;
		return e;
	}

	return this;
}

ExpEmit FxIfStatement::Emit(VMFunctionBuilder *build)
{
	ExpEmit v;
	size_t jumpspot = ~0u;

	TArray<size_t> yes, no;
	Condition->EmitCompare(build, WhenTrue == nullptr, yes, no);

	if (WhenTrue != nullptr)
	{
		build->BackpatchListToHere(yes);
		WhenTrue->EmitStatement(build);
	}
	if (WhenFalse != nullptr)
	{
		if (WhenTrue != nullptr)
		{
			if (!WhenTrue->CheckReturn()) jumpspot = build->Emit(OP_JMP, 0);	// no need to emit a jump if the block returns.
			build->BackpatchListToHere(no);
		}
		WhenFalse->EmitStatement(build);
		if (jumpspot != ~0u) build->BackpatchToHere(jumpspot);
		if (WhenTrue == nullptr) build->BackpatchListToHere(no);
	}
	else
	{
		build->BackpatchListToHere(no);
	}
	return ExpEmit();
}


//==========================================================================
//
// FxIfStatement :: CheckReturn
//
//==========================================================================

bool FxIfStatement::CheckReturn()
{
	//An if statement returns if both branches return. Both branches must be present.
	return WhenTrue != nullptr && WhenTrue->CheckReturn() &&
			WhenFalse != nullptr && WhenFalse->CheckReturn();
}

//==========================================================================
//
// FxLoopStatement :: Resolve
//
// saves the loop pointer in the context and sets this object as the current loop
// so that continues and breaks always resolve to the innermost loop.
//
//==========================================================================

FxExpression *FxLoopStatement::Resolve(FCompileContext &ctx)
{
	auto outerctrl = ctx.ControlStmt;
	auto outer = ctx.Loop;
	ctx.ControlStmt = this;
	ctx.Loop = this;
	auto x = DoResolve(ctx);
	ctx.Loop = outer;
	ctx.ControlStmt = outerctrl;
	return x;
}

void FxLoopStatement::Backpatch(VMFunctionBuilder *build, size_t loopstart, size_t loopend)
{
	// Give a proper address to any break/continue statement within this loop.
	for (unsigned int i = 0; i < Jumps.Size(); i++)
	{
		if (Jumps[i]->Token == TK_Break)
		{
			build->Backpatch(Jumps[i]->Address, loopend);
		}
		else
		{ // Continue statement.
			build->Backpatch(Jumps[i]->Address, loopstart);
		}
	}
}

//==========================================================================
//
// FxWhileLoop
//
//==========================================================================

FxWhileLoop::FxWhileLoop(FxExpression *condition, FxExpression *code, const FScriptPosition &pos)
: FxLoopStatement(EFX_WhileLoop, pos), Condition(condition), Code(code)
{
	ValueType = TypeVoid;
}

FxWhileLoop::~FxWhileLoop()
{
	SAFE_DELETE(Condition);
	SAFE_DELETE(Code);
}

FxExpression *FxWhileLoop::DoResolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE_OPT(Condition, ctx);
	SAFE_RESOLVE_OPT(Code, ctx);

	if (Condition == nullptr)
	{
		Condition = new FxConstant(true, ScriptPosition);
	}

	if (Condition->ValueType != TypeBool)
	{
		Condition = new FxBoolCast(Condition);
		SAFE_RESOLVE(Condition, ctx);
	}

	if (Condition->isConstant())
	{
		if (static_cast<FxConstant *>(Condition)->GetValue().GetBool() == false)
		{ // Nothing happens
			FxExpression *nop = new FxNop(ScriptPosition);
			delete this;
			return nop;
		}
		else if (Code == nullptr)
		{ // "while (true) { }"
		  // Someone could be using this for testing.
			ScriptPosition.Message(MSG_WARNING, "Infinite empty loop");
		}
	}

	return this;
}

ExpEmit FxWhileLoop::Emit(VMFunctionBuilder *build)
{
	assert(Condition->ValueType == TypeBool);

	size_t loopstart, loopend;
	TArray<size_t> yes, no;

	// Evaluate the condition and execute/break out of the loop.
	loopstart = build->GetAddress();
	if (!Condition->isConstant())
	{
		Condition->EmitCompare(build, false, yes, no);
	}
	else assert(static_cast<FxConstant *>(Condition)->GetValue().GetBool() == true);

	build->BackpatchListToHere(yes);
	// Execute the loop's content.
	if (Code != nullptr)
	{
		Code->EmitStatement(build);
	}

	// Loop back.
	build->Backpatch(build->Emit(OP_JMP, 0), loopstart);
	build->BackpatchListToHere(no);
	loopend = build->GetAddress();
	Backpatch(build, loopstart, loopend);
	return ExpEmit();
}

//==========================================================================
//
// FxDoWhileLoop
//
//==========================================================================

FxDoWhileLoop::FxDoWhileLoop(FxExpression *condition, FxExpression *code, const FScriptPosition &pos)
: FxLoopStatement(EFX_DoWhileLoop, pos), Condition(condition), Code(code)
{
	ValueType = TypeVoid;
}

FxDoWhileLoop::~FxDoWhileLoop()
{
	SAFE_DELETE(Condition);
	SAFE_DELETE(Code);
}

FxExpression *FxDoWhileLoop::DoResolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Condition, ctx);
	SAFE_RESOLVE_OPT(Code, ctx);

	if (Condition->ValueType != TypeBool)
	{
		Condition = new FxBoolCast(Condition);
		SAFE_RESOLVE(Condition, ctx);
	}

	if (Condition->isConstant())
	{
		if (static_cast<FxConstant *>(Condition)->GetValue().GetBool() == false)
		{ // The code executes once, if any.
			if (Jumps.Size() == 0)
			{ // We would still have to handle the jumps however.
				FxExpression *e = Code;
				if (e == nullptr) e = new FxNop(ScriptPosition);
				Code = nullptr;
				delete this;
				return e;
			}
		}
		else if (Code == nullptr)
		{ // "do { } while (true);"
		  // Someone could be using this for testing.
			ScriptPosition.Message(MSG_WARNING, "Infinite empty loop");
		}
	}

	return this;
}

ExpEmit FxDoWhileLoop::Emit(VMFunctionBuilder *build)
{
	assert(Condition->ValueType == TypeBool);

	size_t loopstart, loopend;
	size_t codestart;

	// Execute the loop's content.
	codestart = build->GetAddress();
	if (Code != nullptr)
	{
		Code->EmitStatement(build);
	}

	// Evaluate the condition and execute/break out of the loop.
	loopstart = build->GetAddress();
	if (!Condition->isConstant())
	{
		TArray<size_t> yes, no;
		Condition->EmitCompare(build, true, yes, no);
		build->BackpatchList(no, codestart);
		build->BackpatchListToHere(yes);
	}
	else if (static_cast<FxConstant *>(Condition)->GetValue().GetBool() == true)
	{ // Always looping
		build->Backpatch(build->Emit(OP_JMP, 0), codestart);
	}
	loopend = build->GetAddress();
	Backpatch(build, loopstart, loopend);

	return ExpEmit();
}

//==========================================================================
//
// FxForLoop
//
//==========================================================================

FxForLoop::FxForLoop(FxExpression *init, FxExpression *condition, FxExpression *iteration, FxExpression *code, const FScriptPosition &pos)
: FxLoopStatement(EFX_ForLoop, pos), Init(init), Condition(condition), Iteration(iteration), Code(code)
{
	ValueType = TypeVoid;
	if (Iteration != nullptr) Iteration->NeedResult = false;
	if (Code != nullptr) Code->NeedResult = false;
}

FxForLoop::~FxForLoop()
{
	SAFE_DELETE(Init);
	SAFE_DELETE(Condition);
	SAFE_DELETE(Iteration);
	SAFE_DELETE(Code);
}

FxExpression *FxForLoop::DoResolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE_OPT(Init, ctx);
	SAFE_RESOLVE_OPT(Condition, ctx);
	SAFE_RESOLVE_OPT(Iteration, ctx);
	SAFE_RESOLVE_OPT(Code, ctx);

	if (Condition != nullptr)
	{
		if (Condition->ValueType != TypeBool)
		{
			Condition = new FxBoolCast(Condition);
			SAFE_RESOLVE(Condition, ctx);
		}

		if (Condition->isConstant())
		{
			if (static_cast<FxConstant *>(Condition)->GetValue().GetBool() == false)
			{ // Nothing happens
				FxExpression *nop = new FxNop(ScriptPosition);
				delete this;
				return nop;
			}
			else
			{ // "for (..; true; ..)"
				delete Condition;
				Condition = nullptr;
			}
		}
	}
	if (Condition == nullptr && Code == nullptr)
	{ // "for (..; ; ..) { }"
	  // Someone could be using this for testing.
		ScriptPosition.Message(MSG_WARNING, "Infinite empty loop");
	}

	return this;
}

ExpEmit FxForLoop::Emit(VMFunctionBuilder *build)
{
	assert((Condition && Condition->ValueType == TypeBool && !Condition->isConstant()) || Condition == nullptr);

	size_t loopstart, loopend;
	size_t codestart;
	TArray<size_t> yes, no;

	// Init statement (only used by DECORATE. ZScript is pulling it before the loop statement and enclosing the entire loop in a compound statement so that Init can have local variables.)
	if (Init != nullptr)
	{
		ExpEmit init = Init->Emit(build);
		init.Free(build);
	}

	// Evaluate the condition and execute/break out of the loop.
	codestart = build->GetAddress();
	if (Condition != nullptr)
	{
		Condition->EmitCompare(build, false, yes, no);
	}

	build->BackpatchListToHere(yes);
	// Execute the loop's content.
	if (Code != nullptr)
	{
		Code->EmitStatement(build);
	}

	// Iteration statement.
	loopstart = build->GetAddress();
	if (Iteration != nullptr)
	{
		ExpEmit iter = Iteration->Emit(build);
		iter.Free(build);
	}
	build->Backpatch(build->Emit(OP_JMP, 0), codestart);

	// End of loop.
	loopend = build->GetAddress();
	build->BackpatchListToHere(no);

	Backpatch(build, loopstart, loopend);
	return ExpEmit();
}

//==========================================================================
//
// FxJumpStatement
//
//==========================================================================

FxJumpStatement::FxJumpStatement(int token, const FScriptPosition &pos)
: FxExpression(EFX_JumpStatement, pos), Token(token)
{
	ValueType = TypeVoid;
}

FxExpression *FxJumpStatement::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();

	if (ctx.ControlStmt != nullptr)
	{
		if (ctx.ControlStmt == ctx.Loop || Token == TK_Continue)
		{
			ctx.Loop->Jumps.Push(this);
		}
		else
		{
			// break in switch.
			static_cast<FxSwitchStatement*>(ctx.ControlStmt)->Breaks.Push(this);
		}
		return this;
	}
	else
	{
		ScriptPosition.Message(MSG_ERROR, "'%s' outside of a loop", Token == TK_Break ? "break" : "continue");
		delete this;
		return nullptr;
	}
}

ExpEmit FxJumpStatement::Emit(VMFunctionBuilder *build)
{
	Address = build->Emit(OP_JMP, 0);

	return ExpEmit();
}

//==========================================================================
//
//==========================================================================

FxReturnStatement::FxReturnStatement(FxExpression *value, const FScriptPosition &pos)
: FxExpression(EFX_ReturnStatement, pos)
{
	if (value != nullptr) Args.Push(value);
	ValueType = TypeVoid;
}

FxReturnStatement::FxReturnStatement(FArgumentList &values, const FScriptPosition &pos)
	: FxExpression(EFX_ReturnStatement, pos)
{
	Args = std::move(values);
	ValueType = TypeVoid;
}

FxReturnStatement::~FxReturnStatement()
{
}

FxExpression *FxReturnStatement::Resolve(FCompileContext &ctx)
{
	bool fail = false;
	CHECKRESOLVED();
	for (auto &Value : Args)
	{
		SAFE_RESOLVE_OPT(Value, ctx);
		fail |= (Value == nullptr);
	}
	if (fail)
	{
		delete this;
		return nullptr;
	}

	PPrototype *retproto;

	if (ctx.ReturnProto != nullptr && ctx.ReturnProto->ReturnTypes.Size() == 0 && ctx.ReturnProto->ReturnTypes.Size() != Args.Size())
	{
		int severity = ctx.Version >= MakeVersion(3, 7) ? MSG_ERROR : MSG_WARNING;
		ScriptPosition.Message(severity, "Incorrect number of return values. Got %u, but expected %u", Args.Size(), ctx.ReturnProto->ReturnTypes.Size());
		if (severity == MSG_ERROR)
		{
			delete this;
			return nullptr;
		}
		// For older script versions this must fall through.
	}
	
	if (Args.Size() == 0)
	{
		TArray<PType *> none(0);
		retproto = NewPrototype(none, none);
	}
	else if (Args.Size() == 1)
	{
		// If we already know the real return type we need at least try to cast the value to its proper type (unless in an anonymous function.)
		if (ctx.ReturnProto != nullptr && ctx.ReturnProto->ReturnTypes.Size() > 0 && ctx.Function->SymbolName != NAME_None)
		{
			Args[0] = new FxTypeCast(Args[0], ctx.ReturnProto->ReturnTypes[0], false, false);
			Args[0] = Args[0]->Resolve(ctx);
			ABORT(Args[0]);
		}
		retproto = Args[0]->ReturnProto();
	}
	else
	{
		for (unsigned i = 0; i < Args.Size(); i++)
		{
			Args[i] = new FxTypeCast(Args[i], ctx.ReturnProto->ReturnTypes[i], false, false);
			Args[i] = Args[i]->Resolve(ctx);
			if (Args[i] == nullptr) fail = true;
		}
		if (fail)
		{
			delete this;
			return nullptr;
		}
		return this;	// no point calling CheckReturn here.
	}

	ctx.CheckReturn(retproto, ScriptPosition);

	return this;
}

ExpEmit FxReturnStatement::Emit(VMFunctionBuilder *build)
{
	TArray<ExpEmit> outs;

	ExpEmit out(0, REGT_NIL);

	// If there's structs to destroy here we need to emit all returns before destroying them.
	if (build->ConstructedStructs.Size())
	{
		for (auto ret : Args)
		{
			ExpEmit r = ret->Emit(build);
			outs.Push(r);
		}
	}

	// call the destructors for all structs requiring one.
	// go in reverse order of construction
	for (int i = build->ConstructedStructs.Size() - 1; i >= 0; i--)
	{
		auto pstr = static_cast<PStruct*>(build->ConstructedStructs[i]->ValueType);
		assert(pstr->mDestructor != nullptr);
		ExpEmit reg(build, REGT_POINTER);
		build->Emit(OP_ADDA_RK, reg.RegNum, build->FramePointer.RegNum, build->GetConstantInt(build->ConstructedStructs[i]->StackOffset));
		FunctionCallEmitter emitters(pstr->mDestructor);
		emitters.AddParameter(reg, false);
		emitters.EmitCall(build);
	}

	// If we return nothing, use a regular RET opcode.
	// Otherwise just return the value we're given.
	if (Args.Size() == 0)
	{
		build->Emit(OP_RET, RET_FINAL, REGT_NIL, 0);
	}
	else if (Args.Size() == 1)
	{
		out = outs.Size() > 0? outs[0] : Args[0]->Emit(build);

		// Check if it is a function call that simplified itself
		// into a tail call in which case we don't emit anything.
		if (!out.Final)
		{
			if (Args[0]->ValueType == TypeVoid)
			{ // Nothing is returned.
				build->Emit(OP_RET, RET_FINAL, REGT_NIL, 0);
			}
			else
			{
				build->Emit(OP_RET, RET_FINAL, EncodeRegType(out), out.RegNum);
			}
		}
	}
	else
	{
		for (unsigned i = 0; i < Args.Size(); i++)
		{
			out = outs.Size() > 0 ? outs[i] : Args[i]->Emit(build);
			build->Emit(OP_RET, i < Args.Size() - 1 ? i : i+RET_FINAL, EncodeRegType(out), out.RegNum);
		}
	}

	out.Final = true;
	return out;
}

VMFunction *FxReturnStatement::GetDirectFunction(PFunction *func, const VersionInfo &ver)
{
	if (Args.Size() == 1)
	{
		return Args[0]->GetDirectFunction(func, ver);
	}
	return nullptr;
}

//==========================================================================
//
//==========================================================================

FxClassTypeCast::FxClassTypeCast(PClassPointer *dtype, FxExpression *x, bool explicitily)
: FxExpression(EFX_ClassTypeCast, x->ScriptPosition)
{
	ValueType = dtype;
	desttype = dtype->ClassRestriction;
	basex=x;
	Explicit = explicitily;
}

//==========================================================================
//
//
//
//==========================================================================

FxClassTypeCast::~FxClassTypeCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxClassTypeCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (basex->ValueType == TypeNullPtr)
	{
		basex->ValueType = ValueType;
		auto x = basex;
		basex = nullptr;
		delete this;
		return x;
	}
	auto to = static_cast<PClassPointer *>(ValueType);
	if (basex->ValueType->isClassPointer())
	{
		auto from = static_cast<PClassPointer *>(basex->ValueType);
		if (from->ClassRestriction->IsDescendantOf(to->ClassRestriction))
		{
			basex->ValueType = to;
			auto x = basex;
			basex = nullptr;
			delete this;
			return x;
		}
		ScriptPosition.Message(MSG_ERROR, "Cannot convert from %s to %s: Incompatible class types", from->ClassRestriction->TypeName.GetChars(), to->ClassRestriction->TypeName.GetChars());
		delete this;
		return nullptr;
	}
	
	if (basex->ValueType != TypeName && basex->ValueType != TypeString)
	{
		ScriptPosition.Message(MSG_ERROR, "Cannot convert %s to class type", basex->ValueType->DescriptiveName());
		delete this;
		return nullptr;
	}

	if (basex->isConstant())
	{
		FName clsname = static_cast<FxConstant *>(basex)->GetValue().GetName();
		PClass *cls = nullptr;

		if (clsname != NAME_None)
		{
			if (Explicit) cls = FindClassType(clsname, ctx);
			else cls = PClass::FindClass(clsname);
			
			if (cls == nullptr || cls->VMType == nullptr)
			{
				/* lax */
				// Since this happens in released WADs it must pass without a terminal error... :(
				ScriptPosition.Message(MSG_OPTERROR,
					"Unknown class name '%s' of type '%s'",
					clsname.GetChars(), desttype->TypeName.GetChars());
				// When originating from DECORATE this must pass, when in ZScript it's an error that must abort the code generation here.
				if (!ctx.FromDecorate)
				{
					delete this;
					return nullptr;
				}
			}
			else
			{
				if (!cls->IsDescendantOf(desttype))
				{
					ScriptPosition.Message(MSG_OPTERROR, "class '%s' is not compatible with '%s'", clsname.GetChars(), desttype->TypeName.GetChars());
					cls = nullptr;
				}
				else ScriptPosition.Message(MSG_DEBUGLOG, "resolving '%s' as class name", clsname.GetChars());
			}
		}
		FxExpression *x = new FxConstant(cls, to, ScriptPosition);
		delete this;
		return x;
	}
	if (basex->ValueType == TypeString)
	{
		basex = new FxNameCast(basex);
	}
	return this;
}

//==========================================================================
//
// 
//
//==========================================================================

static PClass *NativeNameToClass(int _clsname, PClass *desttype)
{
	PClass *cls = nullptr;
	FName clsname = ENamedName(_clsname);
	if (clsname != NAME_None)
	{
		cls = PClass::FindClass(clsname);
		if (cls != nullptr && (cls->VMType == nullptr || !cls->IsDescendantOf(desttype)))
		{
			// does not match required parameters or is invalid.
			return nullptr;
		}
	}
	return cls;
}

DEFINE_ACTION_FUNCTION_NATIVE(DObject, BuiltinNameToClass, NativeNameToClass)
{
	PARAM_PROLOGUE;
	PARAM_NAME(clsname);
	PARAM_CLASS(desttype, DObject);

	ACTION_RETURN_POINTER(NativeNameToClass(clsname, desttype));
}

ExpEmit FxClassTypeCast::Emit(VMFunctionBuilder *build)
{
	if (basex->ValueType != TypeName)
	{
		return ExpEmit(build->GetConstantAddress(nullptr), REGT_POINTER, true);
	}

	// Call the BuiltinNameToClass function to convert from 'name' to class.
	VMFunction *callfunc;
	auto sym = FindBuiltinFunction(NAME_BuiltinNameToClass);

	assert(sym);
	callfunc = sym->Variants[0].Implementation;

	FunctionCallEmitter emitters(callfunc);
	emitters.AddParameter(build, basex);
	emitters.AddParameterPointerConst(const_cast<PClass *>(desttype));
	emitters.AddReturn(REGT_POINTER);
	return emitters.EmitCall(build);
}

//==========================================================================
//
//==========================================================================

FxClassPtrCast::FxClassPtrCast(PClass *dtype, FxExpression *x)
	: FxExpression(EFX_ClassPtrCast, x->ScriptPosition)
{
	ValueType = NewClassPointer(dtype);
	desttype = dtype;
	basex = x;
}

//==========================================================================
//
//
//
//==========================================================================

FxClassPtrCast::~FxClassPtrCast()
{
	SAFE_DELETE(basex);
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxClassPtrCast::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(basex, ctx);

	if (basex->ValueType == TypeNullPtr)
	{
		basex->ValueType = ValueType;
		auto x = basex;
		basex = nullptr;
		delete this;
		return x;
	}
	auto to = static_cast<PClassPointer *>(ValueType);
	if (basex->ValueType->isClassPointer())
	{
		auto from = static_cast<PClassPointer *>(basex->ValueType);
		// Downcast is always ok.
		if (from->ClassRestriction->IsDescendantOf(to->ClassRestriction))
		{
			basex->ValueType = to;
			auto x = basex;
			basex = nullptr;
			delete this;
			return x;
		}
		// Upcast needs a runtime check.
		else if (to->ClassRestriction->IsDescendantOf(from->ClassRestriction))
		{
			return this;
		}
	}
	else if (basex->ValueType == TypeString || basex->ValueType == TypeName)
	{
		FxExpression *x = new FxClassTypeCast(to, basex, true);
		basex = nullptr;
		delete this;
		return x->Resolve(ctx);
	}
	// Everything else is an error.
	ScriptPosition.Message(MSG_ERROR, "Cannot cast %s to %s. The types are incompatible.", basex->ValueType->DescriptiveName(), to->DescriptiveName());
	delete this;
	return nullptr;
}

//==========================================================================
//
// 
//
//==========================================================================

static PClass *NativeClassCast(PClass *from, PClass *to)
{
	return from && to && from->IsDescendantOf(to) ? from : nullptr;
}

DEFINE_ACTION_FUNCTION_NATIVE(DObject, BuiltinClassCast, NativeClassCast)
{
	PARAM_PROLOGUE;
	PARAM_CLASS(from, DObject);
	PARAM_CLASS(to, DObject);
	ACTION_RETURN_POINTER(NativeClassCast(from, to));
}

ExpEmit FxClassPtrCast::Emit(VMFunctionBuilder *build)
{
	ExpEmit clsname = basex->Emit(build);

	VMFunction *callfunc;
	auto sym = FindBuiltinFunction(NAME_BuiltinClassCast);

	assert(sym);
	callfunc = sym->Variants[0].Implementation;

	FunctionCallEmitter emitters(callfunc);
	emitters.AddParameter(clsname, false);
	emitters.AddParameterPointerConst(desttype);

	emitters.AddReturn(REGT_POINTER);
	return emitters.EmitCall(build);
}

//==========================================================================
//
// Symbolic state labels. 
// Conversion will not happen inside the compiler anymore because it causes
// just too many problems.
//
//==========================================================================

FxExpression *FxStateByIndex::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	ABORT(ctx.Class);
	auto vclass = PType::toClass(ctx.Class);
	assert(vclass != nullptr);
	auto aclass = ValidateActor(vclass->Descriptor);

	// This expression type can only be used from actors, for everything else it has already produced a compile error.
	assert(aclass != nullptr && aclass->GetStateCount() > 0);

	if (aclass->GetStateCount() <= index)
	{
		ScriptPosition.Message(MSG_ERROR, "%s: Attempt to jump to non existing state index %d", 
			ctx.Class->TypeName.GetChars(), index);
		delete this;
		return nullptr;
	}
	int symlabel = StateLabels.AddPointer(aclass->GetStates() + index);
	FxExpression *x = new FxConstant(symlabel, ScriptPosition);
	x->ValueType = TypeStateLabel;
	delete this;
	return x;
}

//==========================================================================
//
//
//
//==========================================================================

FxRuntimeStateIndex::FxRuntimeStateIndex(FxExpression *index)
: FxExpression(EFX_RuntimeStateIndex, index->ScriptPosition), Index(index)
{
	ValueType = TypeStateLabel;
}

FxRuntimeStateIndex::~FxRuntimeStateIndex()
{
	SAFE_DELETE(Index);
}

FxExpression *FxRuntimeStateIndex::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	SAFE_RESOLVE(Index, ctx);

	if (!Index->IsNumeric())
	{
		ScriptPosition.Message(MSG_ERROR, "Numeric type expected");
		delete this;
		return nullptr;
	}
	else if (Index->isConstant())
	{
		int index = static_cast<FxConstant *>(Index)->GetValue().GetInt();
		if (index < 0 || (index == 0 && !ctx.FromDecorate))
		{
			ScriptPosition.Message(MSG_ERROR, "State index must be positive");
			delete this;
			return nullptr;
		}
		else if (index == 0)
		{
			int symlabel = StateLabels.AddPointer(nullptr);
			auto x = new FxConstant(symlabel, ScriptPosition);
			delete this;
			x->ValueType = TypeStateLabel;
			return x;
		}
		else
		{
			auto x = new FxStateByIndex(ctx.StateIndex + index, ScriptPosition);
			delete this;
			return x->Resolve(ctx);
		}
	}
	else if (Index->ValueType->GetRegType() != REGT_INT)
	{ // Float.
		Index = new FxIntCast(Index, ctx.FromDecorate);
		SAFE_RESOLVE(Index, ctx);
	}

	auto vclass = PType::toClass(ctx.Class);
	assert(vclass != nullptr);
	auto aclass = ValidateActor(vclass->Descriptor);
	assert(aclass != nullptr && aclass->GetStateCount() > 0);

	symlabel = StateLabels.AddPointer(aclass->GetStates() + ctx.StateIndex);
	ValueType = TypeStateLabel;
	return this;
}

ExpEmit FxRuntimeStateIndex::Emit(VMFunctionBuilder *build)
{
	ExpEmit out = Index->Emit(build);
	// out = (clamp(Index, 0, 32767) << 16) | symlabel | 0x80000000;  0x80000000 is here to make it negative.
	build->Emit(OP_MAX_RK, out.RegNum, out.RegNum, build->GetConstantInt(0));
	build->Emit(OP_MIN_RK, out.RegNum, out.RegNum, build->GetConstantInt(32767));
	build->Emit(OP_SLL_RI, out.RegNum, out.RegNum, 16);
	build->Emit(OP_OR_RK, out.RegNum, out.RegNum, build->GetConstantInt(symlabel|0x80000000));
	return out;
}

//==========================================================================
//
//
//
//==========================================================================

FxMultiNameState::FxMultiNameState(const char *_statestring, const FScriptPosition &pos, PClassActor *checkclass)
	:FxExpression(EFX_MultiNameState, pos)
{
	FName scopename = NAME_None;
	FString statestring = _statestring;
	int scopeindex = statestring.IndexOf("::");

	if (scopeindex >= 0)
	{
		scopename = FName(statestring, scopeindex, false);
		statestring = statestring.Right(statestring.Len() - scopeindex - 2);
	}
	names = MakeStateNameList(statestring);
	names.Insert(0, scopename);
	scope = checkclass;
}

//==========================================================================
//
//
//
//==========================================================================

FxExpression *FxMultiNameState::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	ABORT(ctx.Class);
	int symlabel;

	auto vclass = PType::toClass(ctx.Class);
	//assert(vclass != nullptr);
	auto clstype = vclass == nullptr? nullptr : ValidateActor(vclass->Descriptor);

	if (names[0] == NAME_None)
	{
		scope = nullptr;
	}
	else if (clstype == nullptr)
	{
		// not in an actor, so any further checks are pointless.
		ScriptPosition.Message(MSG_ERROR, "'%s' is not an ancestor of '%s'", names[0].GetChars(), ctx.Class->TypeName.GetChars());
		delete this;
		return nullptr;
	}
	else if (names[0] == NAME_Super)
	{
		scope = ValidateActor(clstype->ParentClass);
	}
	else
	{
		scope = PClass::FindActor(names[0]);
		if (scope == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Unknown class '%s' in state label", names[0].GetChars());
			delete this;
			return nullptr;
		}
		else if (!scope->IsAncestorOf(clstype))
		{
			ScriptPosition.Message(MSG_ERROR, "'%s' is not an ancestor of '%s'", names[0].GetChars(), ctx.Class->TypeName.GetChars());
			delete this;
			return nullptr;
		}
	}
	if (scope != nullptr)
	{
		FState *destination = nullptr;
		// If the label is class specific we can resolve it right here
		if (names[1] != NAME_None)
		{
			destination = scope->FindState(names.Size()-1, &names[1], false);
			if (destination == nullptr)
			{
				ScriptPosition.Message(MSG_OPTERROR, "Unknown state jump destination");
				/* lax */
				return this;
			}
		}
		symlabel = StateLabels.AddPointer(destination);
	}
	else
	{
		names.Delete(0);
		symlabel = StateLabels.AddNames(names);
	}
	FxExpression *x = new FxConstant(symlabel, ScriptPosition);
	x->ValueType = TypeStateLabel;
	delete this;
	return x;
}

//==========================================================================
//
// declares a single local variable (no arrays)
//
//==========================================================================

FxLocalVariableDeclaration::FxLocalVariableDeclaration(PType *type, FName name, FxExpression *initval, int varflags, const FScriptPosition &p)
	:FxExpression(EFX_LocalVariableDeclaration, p)
{
	ValueType = type;
	VarFlags = varflags;
	Name = name;
	RegCount = type == TypeVector2 ? 2 : type == TypeVector3 ? 3 : 1;
	Init = initval;
}

FxLocalVariableDeclaration::~FxLocalVariableDeclaration()
{
	SAFE_DELETE(Init);
}

FxExpression *FxLocalVariableDeclaration::Resolve(FCompileContext &ctx)
{
	CHECKRESOLVED();
	if (ctx.Block == nullptr)
	{
		ScriptPosition.Message(MSG_ERROR, "Variable declaration outside compound statement");
		delete this;
		return nullptr;
	}
	if (ValueType->RegType == REGT_NIL && ValueType != TypeAuto)
	{
		auto sfunc = static_cast<VMScriptFunction *>(ctx.Function->Variants[0].Implementation);
		StackOffset = sfunc->AllocExtraStack(ValueType);
		
		if (Init != nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Cannot initialize non-scalar variable %s here", Name.GetChars());
			delete this;
			return nullptr;
		}
	}
	else if (ValueType !=TypeAuto)
	{
		if (Init) Init = new FxTypeCast(Init, ValueType, false);
		SAFE_RESOLVE_OPT(Init, ctx);
	}
	else
	{
		if (Init == nullptr)
		{
			ScriptPosition.Message(MSG_ERROR, "Automatic type deduction requires an initializer for variable %s", Name.GetChars());
			delete this;
			return nullptr;
		}
		SAFE_RESOLVE_OPT(Init, ctx);
		if (Init->ValueType->RegType == REGT_NIL)
		{
			ScriptPosition.Message(MSG_ERROR, "Cannot initialize non-scalar variable %s here", Name.GetChars());
			delete this;
			return nullptr;
		}
		ValueType = Init->ValueType;
		// check for undersized ints and floats. These are not allowed as local variables.
		if (IsInteger() && ValueType->Align < sizeof(int)) ValueType = TypeSInt32;
		else if (IsFloat() && ValueType->Align < sizeof(double)) ValueType = TypeFloat64;
	}
	if (Name != NAME_None)
	{
		for (auto l : ctx.Block->LocalVars)
		{
			if (l->Name == Name)
			{
				ScriptPosition.Message(MSG_ERROR, "Local variable %s already defined", Name.GetChars());
				l->ScriptPosition.Message(MSG_ERROR, "Original definition is here ");
				delete this;
				return nullptr;
			}
		}
	}
	ctx.Block->LocalVars.Push(this);
	return this;
}

void FxLocalVariableDeclaration::SetReg(ExpEmit emit)
{
	assert(ValueType->GetRegType() == emit.RegType && ValueType->GetRegCount() == emit.RegCount);
	RegNum = emit.RegNum;
}

ExpEmit FxLocalVariableDeclaration::Emit(VMFunctionBuilder *build)
{
	if (ValueType->RegType != REGT_NIL)
	{
		if (Init == nullptr)
		{
			if (RegNum == -1)
			{
				if (!(VarFlags & VARF_Out))
				{
					const int regType = ValueType->GetRegType();
					assert(regType <= REGT_TYPE);

					auto& registers = build->Registers[regType];
					RegNum = registers.Get(RegCount);

					// Check for reused registers and clean them if needed
					bool useDirtyRegisters = false;

					for (int reg = RegNum, end = RegNum + RegCount; reg < end; ++reg)
					{
						if (!registers.IsDirty(reg))
						{
							continue;
						}

						useDirtyRegisters = true;

						switch (regType)
						{
						case REGT_INT:
							build->Emit(OP_LI, reg, 0, 0);
							break;

						case REGT_FLOAT:
							build->Emit(OP_LKF, reg, build->GetConstantFloat(0.0));
							break;

						case REGT_STRING:
							build->Emit(OP_LKS, reg, build->GetConstantString(nullptr));
							break;

						case REGT_POINTER:
							build->Emit(OP_LKP, reg, build->GetConstantAddress(nullptr));
							break;

						default:
							assert(false);
							break;
						}
					}

					if (useDirtyRegisters)
					{
						ScriptPosition.Message(MSG_DEBUGMSG, "Implicit initialization of variable %s", Name.GetChars());
					}
				}
				else
				{
					RegNum = build->Registers[REGT_POINTER].Get(1);
				}
			}
		}
		else
		{
			assert(!(VarFlags & VARF_Out));	// 'out' variables should never be initialized, they can only exist as function parameters.
			ExpEmit emitval = Init->Emit(build);

			int regtype = emitval.RegType;
			if (regtype < REGT_INT || regtype > REGT_TYPE)
			{
				ScriptPosition.Message(MSG_ERROR, "Attempted to assign a non-value");
				return ExpEmit();
			}
			if (emitval.Konst)
			{
				auto constval = static_cast<FxConstant *>(Init);
				RegNum = build->Registers[regtype].Get(1);
				switch (regtype)
				{
				default:
				case REGT_INT:
					build->Emit(OP_LK, RegNum, build->GetConstantInt(constval->GetValue().GetInt()));
					break;

				case REGT_FLOAT:
					build->Emit(OP_LKF, RegNum, build->GetConstantFloat(constval->GetValue().GetFloat()));
					break;

				case REGT_POINTER:
				{
					build->Emit(OP_LKP, RegNum, build->GetConstantAddress(constval->GetValue().GetPointer()));
					break;
				}
				case REGT_STRING:
					build->Emit(OP_LKS, RegNum, build->GetConstantString(constval->GetValue().GetString()));
				}
				emitval.Free(build);
			}
			else if (!emitval.Fixed)
			{
				// take over the register that got allocated while emitting the Init expression.
				RegNum = emitval.RegNum;
			}
			else
			{
				ExpEmit out(build, emitval.RegType, emitval.RegCount);
				build->Emit(ValueType->GetMoveOp(), out.RegNum, emitval.RegNum);
				RegNum = out.RegNum;
			}
		}
	}
	else
	{
		// Init arrays and structs.
		if (ValueType->isStruct())
		{
			auto pstr = static_cast<PStruct*>(ValueType);
			if (pstr->mConstructor != nullptr)
			{
				ExpEmit reg(build, REGT_POINTER);
				build->Emit(OP_ADDA_RK, reg.RegNum, build->FramePointer.RegNum, build->GetConstantInt(StackOffset));
				FunctionCallEmitter emitters(pstr->mConstructor);
				emitters.AddParameter(reg, false);
				emitters.EmitCall(build);
			}
			if (pstr->mDestructor != nullptr) build->ConstructedStructs.Push(this);
		}
	}
	return ExpEmit();
}

void FxLocalVariableDeclaration::Release(VMFunctionBuilder *build)
{
	// Release the register after the containing block gets closed
	if(RegNum != -1)
	{
		build->Registers[ValueType->GetRegType()].Return(RegNum, RegCount);
	}
	else
	{
		if (ValueType->isStruct())
		{
			auto pstr = static_cast<PStruct*>(ValueType);
			if (pstr->mDestructor != nullptr)
			{
				ExpEmit reg(build, REGT_POINTER);
				build->Emit(OP_ADDA_RK, reg.RegNum, build->FramePointer.RegNum, build->GetConstantInt(StackOffset));
				FunctionCallEmitter emitters(pstr->mDestructor);
				emitters.AddParameter(reg, false);
				emitters.EmitCall(build);
			}
			build->ConstructedStructs.Delete(build->ConstructedStructs.Find(this));
		}
	}
	// Stack space will not be released because that would make controlled destruction impossible.
	// For that all local stack variables need to live for the entire execution of a function.
}


FxStaticArray::FxStaticArray(PType *type, FName name, FArgumentList &args, const FScriptPosition &pos)
	: FxLocalVariableDeclaration(NewArray(type, args.Size()), name, nullptr, VARF_Static|VARF_ReadOnly, pos)
{
	ElementType = type;
	ExprType = EFX_StaticArray;
	values = std::move(args);
}

FxExpression *FxStaticArray::Resolve(FCompileContext &ctx)
{
	bool fail = false;
	for (unsigned i = 0; i < values.Size(); i++)
	{
		values[i] = new FxTypeCast(values[i], ElementType, false);
		values[i] = values[i]->Resolve(ctx);
		if (values[i] == nullptr) fail = true;
		else if (!values[i]->isConstant())
		{
			ScriptPosition.Message(MSG_ERROR, "Initializer must be constant");
			fail = true;
		}
	}
	if (fail)
	{
		delete this;
		return nullptr;
	}
	if (ElementType->GetRegType() == REGT_NIL)
	{
		ScriptPosition.Message(MSG_ERROR, "Invalid type for constant array");
		delete this;
		return nullptr;
	}

	ctx.Block->LocalVars.Push(this);
	return this;
}

ExpEmit FxStaticArray::Emit(VMFunctionBuilder *build)
{
	switch (ElementType->GetRegType())
	{
	default:
		assert(false && "Invalid register type");
		break;

	case REGT_INT:
	{
		TArray<int> cvalues;
		for (auto v : values) cvalues.Push(static_cast<FxConstant *>(v)->GetValue().GetInt());
		StackOffset = build->AllocConstantsInt(cvalues.Size(), &cvalues[0]);
		break;
	}
	case REGT_FLOAT:
	{
		TArray<double> cvalues;
		for (auto v : values) cvalues.Push(static_cast<FxConstant *>(v)->GetValue().GetFloat());
		StackOffset = build->AllocConstantsFloat(cvalues.Size(), &cvalues[0]);
		break;
	}
	case REGT_STRING:
	{
		TArray<FString> cvalues;
		for (auto v : values) cvalues.Push(static_cast<FxConstant *>(v)->GetValue().GetString());
		StackOffset = build->AllocConstantsString(cvalues.Size(), &cvalues[0]);
		break;
	}
	case REGT_POINTER:
	{
		TArray<void*> cvalues;
		for (auto v : values) cvalues.Push(static_cast<FxConstant *>(v)->GetValue().GetPointer());
		StackOffset = build->AllocConstantsAddress(cvalues.Size(), &cvalues[0]);
		break;
	}
	}
	return ExpEmit();
}

FxLocalArrayDeclaration::FxLocalArrayDeclaration(PType *type, FName name, FArgumentList &args, int varflags, const FScriptPosition &pos)
	: FxLocalVariableDeclaration(type, name, nullptr, varflags, pos)
{
	ExprType = EFX_LocalArrayDeclaration;
	values = std::move(args);
	clearExpr = nullptr;
}

FxExpression *FxLocalArrayDeclaration::Resolve(FCompileContext &ctx)
{
	if (isresolved)
	{
		return this;
	}

	FxLocalVariableDeclaration::Resolve(ctx);

	auto stackVar = new FxStackVariable(ValueType, StackOffset, ScriptPosition);
	auto elementType = (static_cast<PArray *> (ValueType))->ElementType;
	auto elementCount = (static_cast<PArray *> (ValueType))->ElementCount;

	// We HAVE to clear dynamic arrays before initializing them
	if (IsDynamicArray())
	{
		FArgumentList argsList;
		argsList.Clear();

		clearExpr = new FxMemberFunctionCall(stackVar, "Clear", argsList, (const FScriptPosition) ScriptPosition);
		SAFE_RESOLVE(clearExpr, ctx);
	}

	if (values.Size() > elementCount)
	{
		ScriptPosition.Message(MSG_ERROR, "Initializer contains more elements than the array can contain");
		delete this;
		return nullptr;
	}

	for (unsigned int i = 0; i < values.Size(); i++)
	{
		if (values[i] == nullptr)
		{
			delete this;
			return nullptr;
		}

		FxExpression *v = new FxTypeCast(values[i], elementType, false);
		SAFE_RESOLVE(v, ctx);
		if (v == nullptr)
		{
			delete this;
			return nullptr;
		}

		if (!IsDynamicArray())
		{
			if (v->IsNativeStruct() && elementType->isRealPointer() && elementType->toPointer()->PointedType == v->ValueType)
			{
				// Allow conversion of native structs to pointers of the same type.
				// For all other types this is not needed. Structs are not assignable and classes can only exist as references.
				bool writable;
				v->RequestAddress(ctx, &writable);
				v->ValueType = elementType;
			}
		}
		else
		{
			FArgumentList argsList;
			argsList.Clear();
			argsList.Push(v);

			FxExpression *funcCall = new FxMemberFunctionCall(stackVar, NAME_Push, argsList, (const FScriptPosition) v->ScriptPosition);
			SAFE_RESOLVE(funcCall, ctx);

			v = funcCall;
		}

		values[i] = v;
	}

	return this;
}

ExpEmit FxLocalArrayDeclaration::Emit(VMFunctionBuilder *build)
{
	assert(!(VarFlags & VARF_Out));	// 'out' variables should never be initialized, they can only exist as function parameters.

	if (IsDynamicArray() && clearExpr != nullptr)
	{
		clearExpr->Emit(build);
	}

	auto elementSizeConst = build->GetConstantInt(static_cast<PArray *>(ValueType)->ElementSize);
	auto arrOffsetReg = build->Registers[REGT_INT].Get(1);
	build->Emit(OP_LK, arrOffsetReg, build->GetConstantInt(StackOffset));

	for (auto v : values)
	{
		ExpEmit emitval = v->Emit(build);

		if (IsDynamicArray())
		{
			continue;
		}

		int regtype = emitval.RegType;
		if (regtype < REGT_INT || regtype > REGT_TYPE)
		{
			ScriptPosition.Message(MSG_ERROR, "Attempted to assign a non-value");
			return ExpEmit();
		}
		if (emitval.Konst)
		{
			auto constval = static_cast<FxConstant *>(v);
			int regNum = build->Registers[regtype].Get(1);
			switch (regtype)
			{
			default:
			case REGT_INT:
				build->Emit(OP_LK, regNum, build->GetConstantInt(constval->GetValue().GetInt()));
				build->Emit(OP_SW_R, build->FramePointer.RegNum, regNum, arrOffsetReg);
				break;

			case REGT_FLOAT:
				build->Emit(OP_LKF, regNum, build->GetConstantFloat(constval->GetValue().GetFloat()));
				build->Emit(OP_SDP_R, build->FramePointer.RegNum, regNum, arrOffsetReg);
				break;

			case REGT_POINTER:
				build->Emit(OP_LKP, regNum, build->GetConstantAddress(constval->GetValue().GetPointer()));
				build->Emit(OP_SP_R, build->FramePointer.RegNum, regNum, arrOffsetReg);
				break;

			case REGT_STRING:
				build->Emit(OP_LKS, regNum, build->GetConstantString(constval->GetValue().GetString()));
				build->Emit(OP_SS_R, build->FramePointer.RegNum, regNum, arrOffsetReg);
				break;
			}
			build->Registers[regtype].Return(regNum, 1);
			
			emitval.Free(build);
		}
		else
		{
			switch (regtype)
			{
			default:
			case REGT_INT:
				build->Emit(OP_SW_R, build->FramePointer.RegNum, emitval.RegNum, arrOffsetReg);
				break;

			case REGT_FLOAT:
				build->Emit(OP_SDP_R, build->FramePointer.RegNum, emitval.RegNum, arrOffsetReg);
				break;

			case REGT_POINTER:
				build->Emit(OP_SP_R, build->FramePointer.RegNum, emitval.RegNum, arrOffsetReg);
				break;

			case REGT_STRING:
				build->Emit(OP_SS_R, build->FramePointer.RegNum, emitval.RegNum, arrOffsetReg);
				break;
			}
			emitval.Free(build);
		}

		build->Emit(OP_ADD_RK, arrOffsetReg, arrOffsetReg, elementSizeConst);
	}
	build->Registers[REGT_INT].Return(arrOffsetReg, 1);

	return ExpEmit();
}