/
dcast.d
3660 lines (3325 loc) · 120 KB
/
dcast.d
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/**
* Compiler implementation of the
* $(LINK2 http://www.dlang.org, D programming language).
*
* Copyright: Copyright (c) 1999-2017 by Digital Mars, All Rights Reserved
* Authors: $(LINK2 http://www.digitalmars.com, Walter Bright)
* License: $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
* Source: $(LINK2 https://github.com/dlang/dmd/blob/master/src/ddmd/dcast.d, _dcast.d)
*/
module ddmd.dcast;
// Online documentation: https://dlang.org/phobos/ddmd_dcast.html
import core.stdc.stdio;
import core.stdc.string;
import ddmd.aggregate;
import ddmd.aliasthis;
import ddmd.arrayop;
import ddmd.arraytypes;
import ddmd.dclass;
import ddmd.declaration;
import ddmd.dscope;
import ddmd.dstruct;
import ddmd.dsymbol;
import ddmd.errors;
import ddmd.expression;
import ddmd.expressionsem;
import ddmd.func;
import ddmd.globals;
import ddmd.impcnvtab;
import ddmd.init;
import ddmd.intrange;
import ddmd.mtype;
import ddmd.opover;
import ddmd.root.ctfloat;
import ddmd.root.outbuffer;
import ddmd.root.rmem;
import ddmd.semantic;
import ddmd.tokens;
import ddmd.typesem;
import ddmd.utf;
import ddmd.visitor;
enum LOG = false;
/**************************************
* Do an implicit cast.
* Issue error if it can't be done.
*/
extern (C++) Expression implicitCastTo(Expression e, Scope* sc, Type t)
{
extern (C++) final class ImplicitCastTo : Visitor
{
alias visit = super.visit;
public:
Type t;
Scope* sc;
Expression result;
extern (D) this(Scope* sc, Type t)
{
this.sc = sc;
this.t = t;
}
override void visit(Expression e)
{
//printf("Expression.implicitCastTo(%s of type %s) => %s\n", e.toChars(), e.type.toChars(), t.toChars());
MATCH match = e.implicitConvTo(t);
if (match)
{
if (match == MATCH.constant && (e.type.constConv(t) || !e.isLvalue() && e.type.equivalent(t)))
{
/* Do not emit CastExp for const conversions and
* unique conversions on rvalue.
*/
result = e.copy();
result.type = t;
return;
}
result = e.castTo(sc, t);
return;
}
result = e.optimize(WANTvalue);
if (result != e)
{
result.accept(this);
return;
}
if (t.ty != Terror && e.type.ty != Terror)
{
if (!t.deco)
{
e.error("forward reference to type `%s`", t.toChars());
}
else
{
//printf("type %p ty %d deco %p\n", type, type.ty, type.deco);
//type = type.typeSemantic(loc, sc);
//printf("type %s t %s\n", type.deco, t.deco);
e.error("cannot implicitly convert expression `%s` of type `%s` to `%s`",
e.toChars(), e.type.toChars(), t.toChars());
}
}
result = new ErrorExp();
}
override void visit(StringExp e)
{
//printf("StringExp::implicitCastTo(%s of type %s) => %s\n", e.toChars(), e.type.toChars(), t.toChars());
visit(cast(Expression)e);
if (result.op == TOKstring)
{
// Retain polysemous nature if it started out that way
(cast(StringExp)result).committed = e.committed;
}
}
override void visit(ErrorExp e)
{
result = e;
}
override void visit(FuncExp e)
{
//printf("FuncExp::implicitCastTo type = %p %s, t = %s\n", e.type, e.type ? e.type.toChars() : NULL, t.toChars());
FuncExp fe;
if (e.matchType(t, sc, &fe) > MATCH.nomatch)
{
result = fe;
return;
}
visit(cast(Expression)e);
}
override void visit(ArrayLiteralExp e)
{
visit(cast(Expression)e);
Type tb = result.type.toBasetype();
if (tb.ty == Tarray)
semanticTypeInfo(sc, (cast(TypeDArray)tb).next);
}
override void visit(SliceExp e)
{
visit(cast(Expression)e);
if (result.op != TOKslice)
return;
e = cast(SliceExp)result;
if (e.e1.op == TOKarrayliteral)
{
ArrayLiteralExp ale = cast(ArrayLiteralExp)e.e1;
Type tb = t.toBasetype();
Type tx;
if (tb.ty == Tsarray)
tx = tb.nextOf().sarrayOf(ale.elements ? ale.elements.dim : 0);
else
tx = tb.nextOf().arrayOf();
e.e1 = ale.implicitCastTo(sc, tx);
}
}
}
scope ImplicitCastTo v = new ImplicitCastTo(sc, t);
e.accept(v);
return v.result;
}
/*******************************************
* Return MATCH level of implicitly converting e to type t.
* Don't do the actual cast; don't change e.
*/
extern (C++) MATCH implicitConvTo(Expression e, Type t)
{
extern (C++) final class ImplicitConvTo : Visitor
{
alias visit = super.visit;
public:
Type t;
MATCH result;
extern (D) this(Type t)
{
this.t = t;
result = MATCH.nomatch;
}
override void visit(Expression e)
{
version (none)
{
printf("Expression::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
//static int nest; if (++nest == 10) assert(0);
if (t == Type.terror)
return;
if (!e.type)
{
e.error("`%s` is not an expression", e.toChars());
e.type = Type.terror;
}
Expression ex = e.optimize(WANTvalue);
if (ex.type.equals(t))
{
result = MATCH.exact;
return;
}
if (ex != e)
{
//printf("\toptimized to %s of type %s\n", e.toChars(), e.type.toChars());
result = ex.implicitConvTo(t);
return;
}
MATCH match = e.type.implicitConvTo(t);
if (match != MATCH.nomatch)
{
result = match;
return;
}
/* See if we can do integral narrowing conversions
*/
if (e.type.isintegral() && t.isintegral() && e.type.isTypeBasic() && t.isTypeBasic())
{
IntRange src = getIntRange(e);
IntRange target = IntRange.fromType(t);
if (target.contains(src))
{
result = MATCH.convert;
return;
}
}
}
/******
* Given expression e of type t, see if we can implicitly convert e
* to type tprime, where tprime is type t with mod bits added.
* Returns:
* match level
*/
static MATCH implicitMod(Expression e, Type t, MOD mod)
{
Type tprime;
if (t.ty == Tpointer)
tprime = t.nextOf().castMod(mod).pointerTo();
else if (t.ty == Tarray)
tprime = t.nextOf().castMod(mod).arrayOf();
else if (t.ty == Tsarray)
tprime = t.nextOf().castMod(mod).sarrayOf(t.size() / t.nextOf().size());
else
tprime = t.castMod(mod);
return e.implicitConvTo(tprime);
}
static MATCH implicitConvToAddMin(BinExp e, Type t)
{
/* Is this (ptr +- offset)? If so, then ask ptr
* if the conversion can be done.
* This is to support doing things like implicitly converting a mutable unique
* pointer to an immutable pointer.
*/
Type tb = t.toBasetype();
Type typeb = e.type.toBasetype();
if (typeb.ty != Tpointer || tb.ty != Tpointer)
return MATCH.nomatch;
Type t1b = e.e1.type.toBasetype();
Type t2b = e.e2.type.toBasetype();
if (t1b.ty == Tpointer && t2b.isintegral() && t1b.equivalent(tb))
{
// ptr + offset
// ptr - offset
MATCH m = e.e1.implicitConvTo(t);
return (m > MATCH.constant) ? MATCH.constant : m;
}
if (t2b.ty == Tpointer && t1b.isintegral() && t2b.equivalent(tb))
{
// offset + ptr
MATCH m = e.e2.implicitConvTo(t);
return (m > MATCH.constant) ? MATCH.constant : m;
}
return MATCH.nomatch;
}
override void visit(AddExp e)
{
version (none)
{
printf("AddExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
visit(cast(Expression)e);
if (result == MATCH.nomatch)
result = implicitConvToAddMin(e, t);
}
override void visit(MinExp e)
{
version (none)
{
printf("MinExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
visit(cast(Expression)e);
if (result == MATCH.nomatch)
result = implicitConvToAddMin(e, t);
}
override void visit(IntegerExp e)
{
version (none)
{
printf("IntegerExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
MATCH m = e.type.implicitConvTo(t);
if (m >= MATCH.constant)
{
result = m;
return;
}
TY ty = e.type.toBasetype().ty;
TY toty = t.toBasetype().ty;
TY oldty = ty;
if (m == MATCH.nomatch && t.ty == Tenum)
return;
if (t.ty == Tvector)
{
TypeVector tv = cast(TypeVector)t;
TypeBasic tb = tv.elementType();
if (tb.ty == Tvoid)
return;
toty = tb.ty;
}
switch (ty)
{
case Tbool:
case Tint8:
case Tchar:
case Tuns8:
case Tint16:
case Tuns16:
case Twchar:
ty = Tint32;
break;
case Tdchar:
ty = Tuns32;
break;
default:
break;
}
// Only allow conversion if no change in value
dinteger_t value = e.toInteger();
switch (toty)
{
case Tbool:
if ((value & 1) != value)
return;
break;
case Tint8:
if (ty == Tuns64 && value & ~0x7FU)
return;
else if (cast(byte)value != value)
return;
break;
case Tchar:
if ((oldty == Twchar || oldty == Tdchar) && value > 0x7F)
return;
goto case Tuns8;
case Tuns8:
//printf("value = %llu %llu\n", (dinteger_t)(unsigned char)value, value);
if (cast(ubyte)value != value)
return;
break;
case Tint16:
if (ty == Tuns64 && value & ~0x7FFFU)
return;
else if (cast(short)value != value)
return;
break;
case Twchar:
if (oldty == Tdchar && value > 0xD7FF && value < 0xE000)
return;
goto case Tuns16;
case Tuns16:
if (cast(ushort)value != value)
return;
break;
case Tint32:
if (ty == Tuns32)
{
}
else if (ty == Tuns64 && value & ~0x7FFFFFFFU)
return;
else if (cast(int)value != value)
return;
break;
case Tuns32:
if (ty == Tint32)
{
}
else if (cast(uint)value != value)
return;
break;
case Tdchar:
if (value > 0x10FFFFU)
return;
break;
case Tfloat32:
{
float f;
if (e.type.isunsigned())
{
f = cast(float)value;
if (f != value)
return;
}
else
{
f = cast(float)cast(sinteger_t)value;
if (f != cast(sinteger_t)value)
return;
}
break;
}
case Tfloat64:
{
double f;
if (e.type.isunsigned())
{
f = cast(double)value;
if (f != value)
return;
}
else
{
f = cast(double)cast(sinteger_t)value;
if (f != cast(sinteger_t)value)
return;
}
break;
}
case Tfloat80:
{
if (e.type.isunsigned())
{
const f = real_t(value);
if (cast(dinteger_t)f != value) // isn't this a noop, because the compiler prefers ld
return;
}
else
{
const f = real_t(cast(sinteger_t)value);
if (cast(sinteger_t)f != cast(sinteger_t)value)
return;
}
break;
}
case Tpointer:
//printf("type = %s\n", type.toBasetype()->toChars());
//printf("t = %s\n", t.toBasetype()->toChars());
if (ty == Tpointer && e.type.toBasetype().nextOf().ty == t.toBasetype().nextOf().ty)
{
/* Allow things like:
* const char* P = cast(char *)3;
* char* q = P;
*/
break;
}
goto default;
default:
visit(cast(Expression)e);
return;
}
//printf("MATCH.convert\n");
result = MATCH.convert;
}
override void visit(ErrorExp e)
{
// no match
}
override void visit(NullExp e)
{
version (none)
{
printf("NullExp::implicitConvTo(this=%s, type=%s, t=%s, committed = %d)\n", e.toChars(), e.type.toChars(), t.toChars(), e.committed);
}
if (e.type.equals(t))
{
result = MATCH.exact;
return;
}
/* Allow implicit conversions from immutable to mutable|const,
* and mutable to immutable. It works because, after all, a null
* doesn't actually point to anything.
*/
if (t.equivalent(e.type))
{
result = MATCH.constant;
return;
}
visit(cast(Expression)e);
}
override void visit(StructLiteralExp e)
{
version (none)
{
printf("StructLiteralExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
visit(cast(Expression)e);
if (result != MATCH.nomatch)
return;
if (e.type.ty == t.ty && e.type.ty == Tstruct && (cast(TypeStruct)e.type).sym == (cast(TypeStruct)t).sym)
{
result = MATCH.constant;
for (size_t i = 0; i < e.elements.dim; i++)
{
Expression el = (*e.elements)[i];
if (!el)
continue;
Type te = el.type;
te = e.sd.fields[i].type.addMod(t.mod);
MATCH m2 = el.implicitConvTo(te);
//printf("\t%s => %s, match = %d\n", el.toChars(), te.toChars(), m2);
if (m2 < result)
result = m2;
}
}
}
override void visit(StringExp e)
{
version (none)
{
printf("StringExp::implicitConvTo(this=%s, committed=%d, type=%s, t=%s)\n", e.toChars(), e.committed, e.type.toChars(), t.toChars());
}
if (!e.committed && t.ty == Tpointer && t.nextOf().ty == Tvoid)
return;
if (e.type.ty == Tsarray || e.type.ty == Tarray || e.type.ty == Tpointer)
{
TY tyn = e.type.nextOf().ty;
if (tyn == Tchar || tyn == Twchar || tyn == Tdchar)
{
switch (t.ty)
{
case Tsarray:
if (e.type.ty == Tsarray)
{
TY tynto = t.nextOf().ty;
if (tynto == tyn)
{
if ((cast(TypeSArray)e.type).dim.toInteger() == (cast(TypeSArray)t).dim.toInteger())
{
result = MATCH.exact;
}
return;
}
if (tynto == Tchar || tynto == Twchar || tynto == Tdchar)
{
if (e.committed && tynto != tyn)
return;
size_t fromlen = e.numberOfCodeUnits(tynto);
size_t tolen = cast(size_t)(cast(TypeSArray)t).dim.toInteger();
if (tolen < fromlen)
return;
if (tolen != fromlen)
{
// implicit length extending
result = MATCH.convert;
return;
}
}
if (!e.committed && (tynto == Tchar || tynto == Twchar || tynto == Tdchar))
{
result = MATCH.exact;
return;
}
}
else if (e.type.ty == Tarray)
{
TY tynto = t.nextOf().ty;
if (tynto == Tchar || tynto == Twchar || tynto == Tdchar)
{
if (e.committed && tynto != tyn)
return;
size_t fromlen = e.numberOfCodeUnits(tynto);
size_t tolen = cast(size_t)(cast(TypeSArray)t).dim.toInteger();
if (tolen < fromlen)
return;
if (tolen != fromlen)
{
// implicit length extending
result = MATCH.convert;
return;
}
}
if (tynto == tyn)
{
result = MATCH.exact;
return;
}
if (!e.committed && (tynto == Tchar || tynto == Twchar || tynto == Tdchar))
{
result = MATCH.exact;
return;
}
}
goto case; /+ fall through +/
case Tarray:
case Tpointer:
Type tn = t.nextOf();
MATCH m = MATCH.exact;
if (e.type.nextOf().mod != tn.mod)
{
if (!tn.isConst())
return;
m = MATCH.constant;
}
if (!e.committed)
{
switch (tn.ty)
{
case Tchar:
if (e.postfix == 'w' || e.postfix == 'd')
m = MATCH.convert;
result = m;
return;
case Twchar:
if (e.postfix != 'w')
m = MATCH.convert;
result = m;
return;
case Tdchar:
if (e.postfix != 'd')
m = MATCH.convert;
result = m;
return;
default:
break;
}
}
break;
default:
break;
}
}
}
visit(cast(Expression)e);
}
override void visit(ArrayLiteralExp e)
{
version (none)
{
printf("ArrayLiteralExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
Type tb = t.toBasetype();
Type typeb = e.type.toBasetype();
if ((tb.ty == Tarray || tb.ty == Tsarray) &&
(typeb.ty == Tarray || typeb.ty == Tsarray))
{
result = MATCH.exact;
Type typen = typeb.nextOf().toBasetype();
if (tb.ty == Tsarray)
{
TypeSArray tsa = cast(TypeSArray)tb;
if (e.elements.dim != tsa.dim.toInteger())
result = MATCH.nomatch;
}
Type telement = tb.nextOf();
if (!e.elements.dim)
{
if (typen.ty != Tvoid)
result = typen.implicitConvTo(telement);
}
else
{
if (e.basis)
{
MATCH m = e.basis.implicitConvTo(telement);
if (m < result)
result = m;
}
for (size_t i = 0; i < e.elements.dim; i++)
{
Expression el = (*e.elements)[i];
if (result == MATCH.nomatch)
break;
if (!el)
continue;
MATCH m = el.implicitConvTo(telement);
if (m < result)
result = m; // remember worst match
}
}
if (!result)
result = e.type.implicitConvTo(t);
return;
}
else if (tb.ty == Tvector && (typeb.ty == Tarray || typeb.ty == Tsarray))
{
result = MATCH.exact;
// Convert array literal to vector type
TypeVector tv = cast(TypeVector)tb;
TypeSArray tbase = cast(TypeSArray)tv.basetype;
assert(tbase.ty == Tsarray);
const edim = e.elements.dim;
const tbasedim = tbase.dim.toInteger();
if (edim > tbasedim)
{
result = MATCH.nomatch;
return;
}
Type telement = tv.elementType();
if (edim < tbasedim)
{
Expression el = typeb.nextOf.defaultInitLiteral(e.loc);
MATCH m = el.implicitConvTo(telement);
if (m < result)
result = m; // remember worst match
}
foreach (i; 0 .. edim)
{
Expression el = (*e.elements)[i];
MATCH m = el.implicitConvTo(telement);
if (m < result)
result = m; // remember worst match
if (result == MATCH.nomatch)
break; // no need to check for worse
}
return;
}
visit(cast(Expression)e);
}
override void visit(AssocArrayLiteralExp e)
{
Type tb = t.toBasetype();
Type typeb = e.type.toBasetype();
if (tb.ty == Taarray && typeb.ty == Taarray)
{
result = MATCH.exact;
for (size_t i = 0; i < e.keys.dim; i++)
{
Expression el = (*e.keys)[i];
MATCH m = el.implicitConvTo((cast(TypeAArray)tb).index);
if (m < result)
result = m; // remember worst match
if (result == MATCH.nomatch)
break; // no need to check for worse
el = (*e.values)[i];
m = el.implicitConvTo(tb.nextOf());
if (m < result)
result = m; // remember worst match
if (result == MATCH.nomatch)
break; // no need to check for worse
}
return;
}
else
visit(cast(Expression)e);
}
override void visit(CallExp e)
{
enum LOG = 0;
static if (LOG)
{
printf("CallExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
visit(cast(Expression)e);
if (result != MATCH.nomatch)
return;
/* Allow the result of strongly pure functions to
* convert to immutable
*/
if (e.f && e.f.isReturnIsolated())
{
result = e.type.immutableOf().implicitConvTo(t);
if (result > MATCH.constant) // Match level is MATCH.constant at best.
result = MATCH.constant;
return;
}
/* Conversion is 'const' conversion if:
* 1. function is pure (weakly pure is ok)
* 2. implicit conversion only fails because of mod bits
* 3. each function parameter can be implicitly converted to the mod bits
*/
Type tx = e.f ? e.f.type : e.e1.type;
tx = tx.toBasetype();
if (tx.ty != Tfunction)
return;
TypeFunction tf = cast(TypeFunction)tx;
if (tf.purity == PUREimpure)
return;
if (e.f && e.f.isNested())
return;
/* See if fail only because of mod bits.
*
* https://issues.dlang.org/show_bug.cgi?id=14155
* All pure functions can access global immutable data.
* So the returned pointer may refer an immutable global data,
* and then the returned pointer that points non-mutable object
* cannot be unique pointer.
*
* Example:
* immutable g;
* static this() { g = 1; }
* const(int*) foo() pure { return &g; }
* void test() {
* immutable(int*) ip = foo(); // OK
* int* mp = foo(); // should be disallowed
* }
*/
if (e.type.immutableOf().implicitConvTo(t) < MATCH.constant && e.type.addMod(MODshared).implicitConvTo(t) < MATCH.constant && e.type.implicitConvTo(t.addMod(MODshared)) < MATCH.constant)
{
return;
}
// Allow a conversion to immutable type, or
// conversions of mutable types between thread-local and shared.
/* Get mod bits of what we're converting to
*/
Type tb = t.toBasetype();
MOD mod = tb.mod;
if (tf.isref)
{
}
else
{
Type ti = getIndirection(t);
if (ti)
mod = ti.mod;
}
static if (LOG)
{
printf("mod = x%x\n", mod);
}
if (mod & MODwild)
return; // not sure what to do with this
/* Apply mod bits to each function parameter,
* and see if we can convert the function argument to the modded type
*/
size_t nparams = Parameter.dim(tf.parameters);
size_t j = (tf.linkage == LINKd && tf.varargs == 1); // if TypeInfoArray was prepended
if (e.e1.op == TOKdotvar)
{
/* Treat 'this' as just another function argument
*/
DotVarExp dve = cast(DotVarExp)e.e1;
Type targ = dve.e1.type;
if (targ.constConv(targ.castMod(mod)) == MATCH.nomatch)
return;
}
for (size_t i = j; i < e.arguments.dim; ++i)
{
Expression earg = (*e.arguments)[i];
Type targ = earg.type.toBasetype();
static if (LOG)
{
printf("[%d] earg: %s, targ: %s\n", cast(int)i, earg.toChars(), targ.toChars());
}
if (i - j < nparams)
{
Parameter fparam = Parameter.getNth(tf.parameters, i - j);
if (fparam.storageClass & STClazy)
return; // not sure what to do with this
Type tparam = fparam.type;
if (!tparam)
continue;
if (fparam.storageClass & (STCout | STCref))
{
if (targ.constConv(tparam.castMod(mod)) == MATCH.nomatch)
return;
continue;
}
}
static if (LOG)
{
printf("[%d] earg: %s, targm: %s\n", cast(int)i, earg.toChars(), targ.addMod(mod).toChars());
}
if (implicitMod(earg, targ, mod) == MATCH.nomatch)
return;
}
/* Success
*/
result = MATCH.constant;
}
override void visit(AddrExp e)
{
version (none)
{
printf("AddrExp::implicitConvTo(this=%s, type=%s, t=%s)\n", e.toChars(), e.type.toChars(), t.toChars());
}
result = e.type.implicitConvTo(t);
//printf("\tresult = %d\n", result);
if (result != MATCH.nomatch)
return;
Type tb = t.toBasetype();
Type typeb = e.type.toBasetype();
// Look for pointers to functions where the functions are overloaded.
if (e.e1.op == TOKoverloadset &&
(tb.ty == Tpointer || tb.ty == Tdelegate) && tb.nextOf().ty == Tfunction)
{
OverExp eo = cast(OverExp)e.e1;
FuncDeclaration f = null;
for (size_t i = 0; i < eo.vars.a.dim; i++)
{
Dsymbol s = eo.vars.a[i];
FuncDeclaration f2 = s.isFuncDeclaration();
assert(f2);
if (f2.overloadExactMatch(tb.nextOf()))
{
if (f)
{
/* Error if match in more than one overload set,
* even if one is a 'better' match than the other.
*/
ScopeDsymbol.multiplyDefined(e.loc, f, f2);
}
else
f = f2;
result = MATCH.exact;
}
}
}
if (e.e1.op == TOKvar &&
typeb.ty == Tpointer && typeb.nextOf().ty == Tfunction &&
tb.ty == Tpointer && tb.nextOf().ty == Tfunction)
{
/* I don't think this can ever happen -
* it should have been
* converted to a SymOffExp.
*/
assert(0);
}
//printf("\tresult = %d\n", result);
}
override void visit(SymOffExp e)
{