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GlobOpt.cpp
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GlobOpt.cpp
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//-------------------------------------------------------------------------------------------------------
// Copyright (C) Microsoft Corporation and contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE.txt file in the project root for full license information.
//-------------------------------------------------------------------------------------------------------
#include "Backend.h"
#if DBG_DUMP
#define DO_MEMOP_TRACE() (PHASE_TRACE(Js::MemOpPhase, this->func) ||\
PHASE_TRACE(Js::MemSetPhase, this->func) ||\
PHASE_TRACE(Js::MemCopyPhase, this->func))
#define DO_MEMOP_TRACE_PHASE(phase) (PHASE_TRACE(Js::MemOpPhase, this->func) || PHASE_TRACE(Js::phase ## Phase, this->func))
#define OUTPUT_MEMOP_TRACE(loop, instr, ...) {\
char16 debugStringBuffer[MAX_FUNCTION_BODY_DEBUG_STRING_SIZE];\
Output::Print(15, _u("Function: %s%s, Loop: %u: "), this->func->GetJITFunctionBody()->GetDisplayName(), this->func->GetDebugNumberSet(debugStringBuffer), loop->GetLoopNumber());\
Output::Print(__VA_ARGS__);\
IR::Instr* __instr__ = instr;\
if(__instr__) __instr__->DumpByteCodeOffset();\
if(__instr__) Output::Print(_u(" (%s)"), Js::OpCodeUtil::GetOpCodeName(__instr__->m_opcode));\
Output::Print(_u("\n"));\
Output::Flush(); \
}
#define TRACE_MEMOP(loop, instr, ...) \
if (DO_MEMOP_TRACE()) {\
Output::Print(_u("TRACE MemOp:"));\
OUTPUT_MEMOP_TRACE(loop, instr, __VA_ARGS__)\
}
#define TRACE_MEMOP_VERBOSE(loop, instr, ...) if(CONFIG_FLAG(Verbose)) {TRACE_MEMOP(loop, instr, __VA_ARGS__)}
#define TRACE_MEMOP_PHASE(phase, loop, instr, ...) \
if (DO_MEMOP_TRACE_PHASE(phase))\
{\
Output::Print(_u("TRACE ") _u(#phase) _u(":"));\
OUTPUT_MEMOP_TRACE(loop, instr, __VA_ARGS__)\
}
#define TRACE_MEMOP_PHASE_VERBOSE(phase, loop, instr, ...) if(CONFIG_FLAG(Verbose)) {TRACE_MEMOP_PHASE(phase, loop, instr, __VA_ARGS__)}
#else
#define DO_MEMOP_TRACE()
#define DO_MEMOP_TRACE_PHASE(phase)
#define OUTPUT_MEMOP_TRACE(loop, instr, ...)
#define TRACE_MEMOP(loop, instr, ...)
#define TRACE_MEMOP_VERBOSE(loop, instr, ...)
#define TRACE_MEMOP_PHASE(phase, loop, instr, ...)
#define TRACE_MEMOP_PHASE_VERBOSE(phase, loop, instr, ...)
#endif
class AutoRestoreVal
{
private:
Value *const originalValue;
Value *const tempValue;
Value * *const valueRef;
public:
AutoRestoreVal(Value *const originalValue, Value * *const tempValueRef)
: originalValue(originalValue), tempValue(*tempValueRef), valueRef(tempValueRef)
{
}
~AutoRestoreVal()
{
if(*valueRef == tempValue)
{
*valueRef = originalValue;
}
}
PREVENT_COPY(AutoRestoreVal);
};
GlobOpt::GlobOpt(Func * func)
: func(func),
intConstantToStackSymMap(nullptr),
intConstantToValueMap(nullptr),
currentValue(FirstNewValueNumber),
prePassLoop(nullptr),
alloc(nullptr),
isCallHelper(false),
inInlinedBuiltIn(false),
rootLoopPrePass(nullptr),
noImplicitCallUsesToInsert(nullptr),
valuesCreatedForClone(nullptr),
valuesCreatedForMerge(nullptr),
instrCountSinceLastCleanUp(0),
isRecursiveCallOnLandingPad(false),
updateInductionVariableValueNumber(false),
isPerformingLoopBackEdgeCompensation(false),
currentRegion(nullptr),
changedSymsAfterIncBailoutCandidate(nullptr),
doTypeSpec(
!IsTypeSpecPhaseOff(func)),
doAggressiveIntTypeSpec(
doTypeSpec &&
DoAggressiveIntTypeSpec(func)),
doAggressiveMulIntTypeSpec(
doTypeSpec &&
!PHASE_OFF(Js::AggressiveMulIntTypeSpecPhase, func) &&
(!func->HasProfileInfo() || !func->GetReadOnlyProfileInfo()->IsAggressiveMulIntTypeSpecDisabled(func->IsLoopBody()))),
doDivIntTypeSpec(
doAggressiveIntTypeSpec &&
(!func->HasProfileInfo() || !func->GetReadOnlyProfileInfo()->IsDivIntTypeSpecDisabled(func->IsLoopBody()))),
doLossyIntTypeSpec(
doTypeSpec &&
DoLossyIntTypeSpec(func)),
doFloatTypeSpec(
doTypeSpec &&
DoFloatTypeSpec(func)),
doArrayCheckHoist(
DoArrayCheckHoist(func)),
doArrayMissingValueCheckHoist(
doArrayCheckHoist &&
DoArrayMissingValueCheckHoist(func)),
doArraySegmentHoist(
doArrayCheckHoist &&
DoArraySegmentHoist(ValueType::GetObject(ObjectType::Int32Array), func)),
doJsArraySegmentHoist(
doArraySegmentHoist &&
DoArraySegmentHoist(ValueType::GetObject(ObjectType::Array), func)),
doArrayLengthHoist(
doArrayCheckHoist &&
DoArrayLengthHoist(func)),
doEliminateArrayAccessHelperCall(
doArrayCheckHoist &&
!PHASE_OFF(Js::EliminateArrayAccessHelperCallPhase, func)),
doTrackRelativeIntBounds(
doAggressiveIntTypeSpec &&
DoPathDependentValues() &&
!PHASE_OFF(Js::Phase::TrackRelativeIntBoundsPhase, func)),
doBoundCheckElimination(
doTrackRelativeIntBounds &&
!PHASE_OFF(Js::Phase::BoundCheckEliminationPhase, func)),
doBoundCheckHoist(
doEliminateArrayAccessHelperCall &&
doBoundCheckElimination &&
DoConstFold() &&
!PHASE_OFF(Js::Phase::BoundCheckHoistPhase, func) &&
(!func->HasProfileInfo() || !func->GetReadOnlyProfileInfo()->IsBoundCheckHoistDisabled(func->IsLoopBody()))),
doLoopCountBasedBoundCheckHoist(
doBoundCheckHoist &&
!PHASE_OFF(Js::Phase::LoopCountBasedBoundCheckHoistPhase, func) &&
(!func->HasProfileInfo() || !func->GetReadOnlyProfileInfo()->IsLoopCountBasedBoundCheckHoistDisabled(func->IsLoopBody()))),
doPowIntIntTypeSpec(
doAggressiveIntTypeSpec &&
(!func->HasProfileInfo() || !func->GetReadOnlyProfileInfo()->IsPowIntIntTypeSpecDisabled())),
doTagChecks(
(!func->HasProfileInfo() || !func->GetReadOnlyProfileInfo()->IsTagCheckDisabled())),
isAsmJSFunc(func->GetJITFunctionBody()->IsAsmJsMode())
{
}
void
GlobOpt::BackwardPass(Js::Phase tag)
{
BEGIN_CODEGEN_PHASE(this->func, tag);
::BackwardPass backwardPass(this->func, this, tag);
backwardPass.Optimize();
END_CODEGEN_PHASE(this->func, tag);
}
void
GlobOpt::Optimize()
{
this->objectTypeSyms = nullptr;
this->func->argInsCount = this->func->GetInParamsCount() - 1; //Don't include "this" pointer in the count.
if (!func->DoGlobOpt())
{
this->lengthEquivBv = nullptr;
this->argumentsEquivBv = nullptr;
this->callerEquivBv = nullptr;
// Still need to run the dead store phase to calculate the live reg on back edge
this->BackwardPass(Js::DeadStorePhase);
CannotAllocateArgumentsObjectOnStack();
return;
}
{
this->lengthEquivBv = this->func->m_symTable->m_propertyEquivBvMap->Lookup(Js::PropertyIds::length, nullptr); // Used to kill live "length" properties
this->argumentsEquivBv = func->m_symTable->m_propertyEquivBvMap->Lookup(Js::PropertyIds::arguments, nullptr); // Used to kill live "arguments" properties
this->callerEquivBv = func->m_symTable->m_propertyEquivBvMap->Lookup(Js::PropertyIds::caller, nullptr); // Used to kill live "caller" properties
// The backward phase needs the glob opt's allocator to allocate the propertyTypeValueMap
// in GlobOpt::EnsurePropertyTypeValue and ranges of instructions where int overflow may be ignored.
// (see BackwardPass::TrackIntUsage)
PageAllocator * pageAllocator = this->func->m_alloc->GetPageAllocator();
NoRecoverMemoryJitArenaAllocator localAlloc(_u("BE-GlobOpt"), pageAllocator, Js::Throw::OutOfMemory);
this->alloc = &localAlloc;
NoRecoverMemoryJitArenaAllocator localTempAlloc(_u("BE-GlobOpt temp"), pageAllocator, Js::Throw::OutOfMemory);
this->tempAlloc = &localTempAlloc;
// The forward passes use info (upwardExposedUses) from the backward pass. This info
// isn't available for some of the symbols created during the backward pass, or the forward pass.
// Keep track of the last symbol for which we're guaranteed to have data.
this->maxInitialSymID = this->func->m_symTable->GetMaxSymID();
#if DBG
this->BackwardPass(Js::CaptureByteCodeRegUsePhase);
#endif
this->BackwardPass(Js::BackwardPhase);
this->ForwardPass();
this->BackwardPass(Js::DeadStorePhase);
}
this->TailDupPass();
}
bool GlobOpt::ShouldExpectConventionalArrayIndexValue(IR::IndirOpnd *const indirOpnd)
{
Assert(indirOpnd);
if(!indirOpnd->GetIndexOpnd())
{
return indirOpnd->GetOffset() >= 0;
}
IR::RegOpnd *const indexOpnd = indirOpnd->GetIndexOpnd();
if(indexOpnd->m_sym->m_isNotNumber)
{
// Typically, single-def or any sym-specific information for type-specialized syms should not be used because all of
// their defs will not have been accounted for until after the forward pass. But m_isNotNumber is only ever changed from
// false to true, so it's okay in this case.
return false;
}
StackSym *indexVarSym = indexOpnd->m_sym;
if(indexVarSym->IsTypeSpec())
{
indexVarSym = indexVarSym->GetVarEquivSym(nullptr);
Assert(indexVarSym);
}
else if(!IsLoopPrePass())
{
// Don't use single-def info or const flags for type-specialized syms, as all of their defs will not have been accounted
// for until after the forward pass. Also, don't use the const flags in a loop prepass because the const flags may not
// be up-to-date.
if (indexOpnd->IsNotInt())
{
return false;
}
StackSym *const indexSym = indexOpnd->m_sym;
if(indexSym->IsIntConst())
{
return indexSym->GetIntConstValue() >= 0;
}
}
Value *const indexValue = CurrentBlockData()->FindValue(indexVarSym);
if(!indexValue)
{
// Treat it as Uninitialized, assume it's going to be valid
return true;
}
ValueInfo *const indexValueInfo = indexValue->GetValueInfo();
int32 indexConstantValue;
if(indexValueInfo->TryGetIntConstantValue(&indexConstantValue))
{
return indexConstantValue >= 0;
}
if(indexValueInfo->IsUninitialized())
{
// Assume it's going to be valid
return true;
}
return indexValueInfo->HasBeenNumber() && !indexValueInfo->HasBeenFloat();
}
//
// Either result is float or 1/x or cst1/cst2 where cst1%cst2 != 0
//
ValueType GlobOpt::GetDivValueType(IR::Instr* instr, Value* src1Val, Value* src2Val, bool specialize)
{
ValueInfo *src1ValueInfo = (src1Val ? src1Val->GetValueInfo() : nullptr);
ValueInfo *src2ValueInfo = (src2Val ? src2Val->GetValueInfo() : nullptr);
if (instr->IsProfiledInstr() && instr->m_func->HasProfileInfo())
{
ValueType resultType = instr->m_func->GetReadOnlyProfileInfo()->GetDivProfileInfo(static_cast<Js::ProfileId>(instr->AsProfiledInstr()->u.profileId));
if (resultType.IsLikelyInt())
{
if (specialize && src1ValueInfo && src2ValueInfo
&& ((src1ValueInfo->IsInt() && src2ValueInfo->IsInt()) ||
(this->DoDivIntTypeSpec() && src1ValueInfo->IsLikelyInt() && src2ValueInfo->IsLikelyInt())))
{
return ValueType::GetInt(true);
}
return resultType;
}
// Consider: Checking that the sources are numbers.
if (resultType.IsLikelyFloat())
{
return ValueType::Float;
}
return resultType;
}
int32 src1IntConstantValue;
if(!src1ValueInfo || !src1ValueInfo->TryGetIntConstantValue(&src1IntConstantValue))
{
return ValueType::Number;
}
if (src1IntConstantValue == 1)
{
return ValueType::Float;
}
int32 src2IntConstantValue;
if(!src2Val || !src2ValueInfo->TryGetIntConstantValue(&src2IntConstantValue))
{
return ValueType::Number;
}
if (src2IntConstantValue // Avoid divide by zero
&& !(src1IntConstantValue == 0x80000000 && src2IntConstantValue == -1) // Avoid integer overflow
&& (src1IntConstantValue % src2IntConstantValue) != 0)
{
return ValueType::Float;
}
return ValueType::Number;
}
void
GlobOpt::ForwardPass()
{
BEGIN_CODEGEN_PHASE(this->func, Js::ForwardPhase);
#if DBG_DUMP
if (Js::Configuration::Global.flags.Trace.IsEnabled(Js::GlobOptPhase, this->func->GetSourceContextId(), this->func->GetLocalFunctionId()))
{
this->func->DumpHeader();
}
if (Js::Configuration::Global.flags.TestTrace.IsEnabled(Js::GlobOptPhase))
{
this->TraceSettings();
}
#endif
// GetConstantCount() gives us the right size to pick for the SparseArray, but we may need more if we've inlined
// functions with constants. There will be a gap in the symbol numbering between the main constants and
// the inlined ones, so we'll most likely need a new array chunk. Make the min size of the array chunks be 64
// in case we have a main function with very few constants and a bunch of constants from inlined functions.
this->byteCodeConstantValueArray = SparseArray<Value>::New(this->alloc, max(this->func->GetJITFunctionBody()->GetConstCount(), 64U));
this->byteCodeConstantValueNumbersBv = JitAnew(this->alloc, BVSparse<JitArenaAllocator>, this->alloc);
this->tempBv = JitAnew(this->alloc, BVSparse<JitArenaAllocator>, this->alloc);
this->prePassCopyPropSym = JitAnew(this->alloc, BVSparse<JitArenaAllocator>, this->alloc);
this->slotSyms = JitAnew(this->alloc, BVSparse<JitArenaAllocator>, this->alloc);
this->byteCodeUses = nullptr;
this->propertySymUse = nullptr;
// changedSymsAfterIncBailoutCandidate helps track building incremental bailout in ForwardPass
this->changedSymsAfterIncBailoutCandidate = JitAnew(alloc, BVSparse<JitArenaAllocator>, alloc);
#if DBG
this->byteCodeUsesBeforeOpt = JitAnew(this->alloc, BVSparse<JitArenaAllocator>, this->alloc);
if (Js::Configuration::Global.flags.Trace.IsEnabled(Js::FieldCopyPropPhase) && this->DoFunctionFieldCopyProp())
{
Output::Print(_u("TRACE: CanDoFieldCopyProp Func: "));
this->func->DumpFullFunctionName();
Output::Print(_u("\n"));
}
#endif
OpndList localNoImplicitCallUsesToInsert(alloc);
this->noImplicitCallUsesToInsert = &localNoImplicitCallUsesToInsert;
IntConstantToStackSymMap localIntConstantToStackSymMap(alloc);
this->intConstantToStackSymMap = &localIntConstantToStackSymMap;
IntConstantToValueMap localIntConstantToValueMap(alloc);
this->intConstantToValueMap = &localIntConstantToValueMap;
Int64ConstantToValueMap localInt64ConstantToValueMap(alloc);
this->int64ConstantToValueMap = &localInt64ConstantToValueMap;
AddrConstantToValueMap localAddrConstantToValueMap(alloc);
this->addrConstantToValueMap = &localAddrConstantToValueMap;
StringConstantToValueMap localStringConstantToValueMap(alloc);
this->stringConstantToValueMap = &localStringConstantToValueMap;
SymIdToInstrMap localPrePassInstrMap(alloc);
this->prePassInstrMap = &localPrePassInstrMap;
ValueSetByValueNumber localValuesCreatedForClone(alloc, 64);
this->valuesCreatedForClone = &localValuesCreatedForClone;
ValueNumberPairToValueMap localValuesCreatedForMerge(alloc, 64);
this->valuesCreatedForMerge = &localValuesCreatedForMerge;
#if DBG
BVSparse<JitArenaAllocator> localFinishedStackLiteralInitFld(alloc);
this->finishedStackLiteralInitFld = &localFinishedStackLiteralInitFld;
#endif
FOREACH_BLOCK_IN_FUNC_EDITING(block, this->func)
{
this->OptBlock(block);
} NEXT_BLOCK_IN_FUNC_EDITING;
if (!PHASE_OFF(Js::MemOpPhase, this->func))
{
ProcessMemOp();
}
this->noImplicitCallUsesToInsert = nullptr;
this->intConstantToStackSymMap = nullptr;
this->intConstantToValueMap = nullptr;
this->int64ConstantToValueMap = nullptr;
this->addrConstantToValueMap = nullptr;
this->stringConstantToValueMap = nullptr;
#if DBG
this->finishedStackLiteralInitFld = nullptr;
uint freedCount = 0;
uint spilledCount = 0;
#endif
FOREACH_BLOCK_IN_FUNC(block, this->func)
{
#if DBG
if (block->GetDataUseCount() == 0)
{
freedCount++;
}
else
{
spilledCount++;
}
#endif
block->SetDataUseCount(0);
if (block->cloneStrCandidates)
{
JitAdelete(this->alloc, block->cloneStrCandidates);
block->cloneStrCandidates = nullptr;
}
} NEXT_BLOCK_IN_FUNC;
// Make sure we free most of them.
Assert(freedCount >= spilledCount);
// this->alloc will be freed right after return, no need to free it here
this->changedSymsAfterIncBailoutCandidate = nullptr;
END_CODEGEN_PHASE(this->func, Js::ForwardPhase);
}
void
GlobOpt::OptBlock(BasicBlock *block)
{
if (this->func->m_fg->RemoveUnreachableBlock(block, this))
{
GOPT_TRACE(_u("Removing unreachable block #%d\n"), block->GetBlockNum());
return;
}
Loop * loop = block->loop;
if (loop && block->isLoopHeader)
{
if (loop != this->prePassLoop)
{
OptLoops(loop);
if (!IsLoopPrePass() && loop->parent)
{
loop->fieldPRESymStores->Or(loop->parent->fieldPRESymStores);
}
if (!this->IsLoopPrePass() && DoFieldPRE(loop))
{
// Note: !IsLoopPrePass means this was a root loop pre-pass. FieldPre() is called once per loop.
this->FieldPRE(loop);
// Re-optimize the landing pad
BasicBlock *landingPad = loop->landingPad;
this->isRecursiveCallOnLandingPad = true;
this->OptBlock(landingPad);
this->isRecursiveCallOnLandingPad = false;
}
}
}
this->currentBlock = block;
PrepareLoopArrayCheckHoist();
block->MergePredBlocksValueMaps(this);
this->intOverflowCurrentlyMattersInRange = true;
this->intOverflowDoesNotMatterRange = this->currentBlock->intOverflowDoesNotMatterRange;
if (!DoFieldCopyProp() && !DoFieldRefOpts())
{
this->KillAllFields(CurrentBlockData()->liveFields);
}
this->tempAlloc->Reset();
if(loop && block->isLoopHeader)
{
loop->firstValueNumberInLoop = this->currentValue;
}
GOPT_TRACE_BLOCK(block, true);
FOREACH_INSTR_IN_BLOCK_EDITING(instr, instrNext, block)
{
GOPT_TRACE_INSTRTRACE(instr);
BailOutInfo* oldBailOutInfo = nullptr;
bool isCheckAuxBailoutNeeded = this->func->IsJitInDebugMode() && !this->IsLoopPrePass();
if (isCheckAuxBailoutNeeded && instr->HasAuxBailOut() && !instr->HasBailOutInfo())
{
oldBailOutInfo = instr->GetBailOutInfo();
Assert(oldBailOutInfo);
}
bool isInstrRemoved = false;
instrNext = this->OptInstr(instr, &isInstrRemoved);
// If we still have instrs with only aux bail out, convert aux bail out back to regular bail out and fill it.
// During OptInstr some instr can be moved out to a different block, in this case bailout info is going to be replaced
// with e.g. loop bailout info which is filled as part of processing that block, thus we don't need to fill it here.
if (isCheckAuxBailoutNeeded && !isInstrRemoved && instr->HasAuxBailOut() && !instr->HasBailOutInfo())
{
if (instr->GetBailOutInfo() == oldBailOutInfo)
{
instr->PromoteAuxBailOut();
FillBailOutInfo(block, instr);
}
else
{
AssertMsg(instr->GetBailOutInfo(), "With aux bailout, the bailout info should not be removed by OptInstr.");
}
}
} NEXT_INSTR_IN_BLOCK_EDITING;
GOPT_TRACE_BLOCK(block, false);
if (block->loop)
{
if (IsLoopPrePass())
{
if (DoBoundCheckHoist())
{
DetectUnknownChangesToInductionVariables(&block->globOptData);
}
}
else
{
isPerformingLoopBackEdgeCompensation = true;
Assert(this->tempBv->IsEmpty());
BVSparse<JitArenaAllocator> tempBv2(this->tempAlloc);
// On loop back-edges, we need to restore the state of the type specialized
// symbols to that of the loop header.
FOREACH_SUCCESSOR_BLOCK(succ, block)
{
if (succ->isLoopHeader && succ->loop->IsDescendentOrSelf(block->loop))
{
BVSparse<JitArenaAllocator> *liveOnBackEdge = block->loop->regAlloc.liveOnBackEdgeSyms;
liveOnBackEdge->Or(block->loop->fieldPRESymStores);
this->tempBv->Minus(block->loop->varSymsOnEntry, block->globOptData.liveVarSyms);
this->tempBv->And(liveOnBackEdge);
this->ToVar(this->tempBv, block);
// Lossy int in the loop header, and no int on the back-edge - need a lossy conversion to int
this->tempBv->Minus(block->loop->lossyInt32SymsOnEntry, block->globOptData.liveInt32Syms);
this->tempBv->And(liveOnBackEdge);
this->ToInt32(this->tempBv, block, true /* lossy */);
// Lossless int in the loop header, and no lossless int on the back-edge - need a lossless conversion to int
this->tempBv->Minus(block->loop->int32SymsOnEntry, block->loop->lossyInt32SymsOnEntry);
tempBv2.Minus(block->globOptData.liveInt32Syms, block->globOptData.liveLossyInt32Syms);
this->tempBv->Minus(&tempBv2);
this->tempBv->And(liveOnBackEdge);
this->ToInt32(this->tempBv, block, false /* lossy */);
this->tempBv->Minus(block->loop->float64SymsOnEntry, block->globOptData.liveFloat64Syms);
this->tempBv->And(liveOnBackEdge);
this->ToFloat64(this->tempBv, block);
// For ints and floats, go aggressive and type specialize in the landing pad any symbol which was specialized on
// entry to the loop body (in the loop header), and is still specialized on this tail, but wasn't specialized in
// the landing pad.
// Lossy int in the loop header and no int in the landing pad - need a lossy conversion to int
// (entry.lossyInt32 - landingPad.int32)
this->tempBv->Minus(block->loop->lossyInt32SymsOnEntry, block->loop->landingPad->globOptData.liveInt32Syms);
this->tempBv->And(liveOnBackEdge);
this->ToInt32(this->tempBv, block->loop->landingPad, true /* lossy */);
// Lossless int in the loop header, and no lossless int in the landing pad - need a lossless conversion to int
// ((entry.int32 - entry.lossyInt32) - (landingPad.int32 - landingPad.lossyInt32))
this->tempBv->Minus(block->loop->int32SymsOnEntry, block->loop->lossyInt32SymsOnEntry);
tempBv2.Minus(
block->loop->landingPad->globOptData.liveInt32Syms,
block->loop->landingPad->globOptData.liveLossyInt32Syms);
this->tempBv->Minus(&tempBv2);
this->tempBv->And(liveOnBackEdge);
this->ToInt32(this->tempBv, block->loop->landingPad, false /* lossy */);
// ((entry.float64 - landingPad.float64) & block.float64)
this->tempBv->Minus(block->loop->float64SymsOnEntry, block->loop->landingPad->globOptData.liveFloat64Syms);
this->tempBv->And(block->globOptData.liveFloat64Syms);
this->tempBv->And(liveOnBackEdge);
this->ToFloat64(this->tempBv, block->loop->landingPad);
if (block->loop->symsRequiringCompensationToMergedValueInfoMap)
{
InsertValueCompensation(block, succ, block->loop->symsRequiringCompensationToMergedValueInfoMap);
}
// Now that we're done with the liveFields within this loop, trim the set to those syms
// that the backward pass told us were live out of the loop.
// This assumes we have no further need of the liveFields within the loop.
if (block->loop->liveOutFields)
{
block->globOptData.liveFields->And(block->loop->liveOutFields);
}
}
} NEXT_SUCCESSOR_BLOCK;
this->tempBv->ClearAll();
isPerformingLoopBackEdgeCompensation = false;
}
}
block->PathDepBranchFolding(this);
#if DBG
// The set of live lossy int32 syms should be a subset of all live int32 syms
this->tempBv->And(block->globOptData.liveInt32Syms, block->globOptData.liveLossyInt32Syms);
Assert(this->tempBv->Count() == block->globOptData.liveLossyInt32Syms->Count());
// The set of live lossy int32 syms should be a subset of live var or float syms (var or float sym containing the lossless
// value of the sym should be live)
this->tempBv->Or(block->globOptData.liveVarSyms, block->globOptData.liveFloat64Syms);
this->tempBv->And(block->globOptData.liveLossyInt32Syms);
Assert(this->tempBv->Count() == block->globOptData.liveLossyInt32Syms->Count());
this->tempBv->ClearAll();
Assert(this->currentBlock == block);
#endif
}
void
GlobOpt::OptLoops(Loop *loop)
{
Assert(loop != nullptr);
#if DBG
if (Js::Configuration::Global.flags.Trace.IsEnabled(Js::FieldCopyPropPhase) &&
!DoFunctionFieldCopyProp() && DoFieldCopyProp(loop))
{
Output::Print(_u("TRACE: CanDoFieldCopyProp Loop: "));
this->func->DumpFullFunctionName();
uint loopNumber = loop->GetLoopNumber();
Assert(loopNumber != Js::LoopHeader::NoLoop);
Output::Print(_u(" Loop: %d\n"), loopNumber);
}
#endif
Loop *previousLoop = this->prePassLoop;
this->prePassLoop = loop;
if (previousLoop == nullptr)
{
Assert(this->rootLoopPrePass == nullptr);
this->rootLoopPrePass = loop;
this->prePassInstrMap->Clear();
if (loop->parent == nullptr)
{
// Outer most loop...
this->prePassCopyPropSym->ClearAll();
}
}
Assert(loop->symsAssignedToInLoop != nullptr);
if (loop->symsUsedBeforeDefined == nullptr)
{
loop->symsUsedBeforeDefined = JitAnew(alloc, BVSparse<JitArenaAllocator>, this->alloc);
loop->likelyIntSymsUsedBeforeDefined = JitAnew(alloc, BVSparse<JitArenaAllocator>, this->alloc);
loop->likelyNumberSymsUsedBeforeDefined = JitAnew(alloc, BVSparse<JitArenaAllocator>, this->alloc);
loop->forceFloat64SymsOnEntry = JitAnew(this->alloc, BVSparse<JitArenaAllocator>, this->alloc);
loop->symsDefInLoop = JitAnew(this->alloc, BVSparse<JitArenaAllocator>, this->alloc);
loop->fieldKilled = JitAnew(alloc, BVSparse<JitArenaAllocator>, this->alloc);
loop->fieldPRESymStores = JitAnew(alloc, BVSparse<JitArenaAllocator>, this->alloc);
loop->allFieldsKilled = false;
}
else
{
loop->symsUsedBeforeDefined->ClearAll();
loop->likelyIntSymsUsedBeforeDefined->ClearAll();
loop->likelyNumberSymsUsedBeforeDefined->ClearAll();
loop->forceFloat64SymsOnEntry->ClearAll();
loop->symsDefInLoop->ClearAll();
loop->fieldKilled->ClearAll();
loop->allFieldsKilled = false;
loop->initialValueFieldMap.Reset();
}
FOREACH_BLOCK_IN_LOOP(block, loop)
{
block->SetDataUseCount(block->GetSuccList()->Count());
OptBlock(block);
} NEXT_BLOCK_IN_LOOP;
if (previousLoop == nullptr)
{
Assert(this->rootLoopPrePass == loop);
this->rootLoopPrePass = nullptr;
}
this->prePassLoop = previousLoop;
}
void
GlobOpt::TailDupPass()
{
FOREACH_LOOP_IN_FUNC_EDITING(loop, this->func)
{
BasicBlock* header = loop->GetHeadBlock();
BasicBlock* loopTail = nullptr;
FOREACH_PREDECESSOR_BLOCK(pred, header)
{
if (loop->IsDescendentOrSelf(pred->loop))
{
loopTail = pred;
break;
}
} NEXT_PREDECESSOR_BLOCK;
if (loopTail)
{
AssertMsg(loopTail->GetLastInstr()->IsBranchInstr(), "LastInstr of loop should always be a branch no?");
if (!loopTail->GetPredList()->HasOne())
{
TryTailDup(loopTail->GetLastInstr()->AsBranchInstr());
}
}
} NEXT_LOOP_IN_FUNC_EDITING;
}
bool
GlobOpt::TryTailDup(IR::BranchInstr *tailBranch)
{
if (PHASE_OFF(Js::TailDupPhase, tailBranch->m_func->GetTopFunc()))
{
return false;
}
if (tailBranch->IsConditional())
{
return false;
}
IR::Instr *instr;
uint instrCount = 0;
for (instr = tailBranch->GetPrevRealInstrOrLabel(); !instr->IsLabelInstr(); instr = instr->GetPrevRealInstrOrLabel())
{
if (instr->HasBailOutInfo())
{
break;
}
if (!OpCodeAttr::CanCSE(instr->m_opcode))
{
// Consider: We could be more aggressive here
break;
}
instrCount++;
if (instrCount > 1)
{
// Consider: If copy handled single-def tmps renaming, we could do more instrs
break;
}
}
if (!instr->IsLabelInstr())
{
return false;
}
IR::LabelInstr *mergeLabel = instr->AsLabelInstr();
IR::Instr *mergeLabelPrev = mergeLabel->m_prev;
// Skip unreferenced labels
while (mergeLabelPrev->IsLabelInstr() && mergeLabelPrev->AsLabelInstr()->labelRefs.Empty())
{
mergeLabelPrev = mergeLabelPrev->m_prev;
}
BasicBlock* labelBlock = mergeLabel->GetBasicBlock();
uint origPredCount = labelBlock->GetPredList()->Count();
uint dupCount = 0;
// We are good to go. Let's do the tail duplication.
FOREACH_SLISTCOUNTED_ENTRY_EDITING(IR::BranchInstr*, branchEntry, &mergeLabel->labelRefs, iter)
{
if (branchEntry->IsUnconditional() && !branchEntry->IsMultiBranch() && branchEntry != mergeLabelPrev && branchEntry != tailBranch)
{
for (instr = mergeLabel->m_next; instr != tailBranch; instr = instr->m_next)
{
branchEntry->InsertBefore(instr->Copy());
}
instr = branchEntry;
branchEntry->ReplaceTarget(mergeLabel, tailBranch->GetTarget());
while(!instr->IsLabelInstr())
{
instr = instr->m_prev;
}
BasicBlock* branchBlock = instr->AsLabelInstr()->GetBasicBlock();
labelBlock->RemovePred(branchBlock, func->m_fg);
func->m_fg->AddEdge(branchBlock, tailBranch->GetTarget()->GetBasicBlock());
dupCount++;
}
} NEXT_SLISTCOUNTED_ENTRY_EDITING;
// If we've duplicated everywhere, tail block is dead and should be removed.
if (dupCount == origPredCount)
{
AssertMsg(mergeLabel->labelRefs.Empty(), "Should not remove block with referenced label.");
func->m_fg->RemoveBlock(labelBlock, nullptr, true);
}
return true;
}
void
GlobOpt::ToVar(BVSparse<JitArenaAllocator> *bv, BasicBlock *block)
{
FOREACH_BITSET_IN_SPARSEBV(id, bv)
{
StackSym *stackSym = this->func->m_symTable->FindStackSym(id);
IR::RegOpnd *newOpnd = IR::RegOpnd::New(stackSym, TyVar, this->func);
IR::Instr *lastInstr = block->GetLastInstr();
if (lastInstr->IsBranchInstr() || lastInstr->m_opcode == Js::OpCode::BailTarget)
{
// If branch is using this symbol, hoist the operand as the ToVar load will get
// inserted right before the branch.
IR::Opnd *src1 = lastInstr->GetSrc1();
if (src1)
{
if (src1->IsRegOpnd() && src1->AsRegOpnd()->m_sym == stackSym)
{
lastInstr->HoistSrc1(Js::OpCode::Ld_A);
}
IR::Opnd *src2 = lastInstr->GetSrc2();
if (src2)
{
if (src2->IsRegOpnd() && src2->AsRegOpnd()->m_sym == stackSym)
{
lastInstr->HoistSrc2(Js::OpCode::Ld_A);
}
}
}
this->ToVar(lastInstr, newOpnd, block, nullptr, false);
}
else
{
IR::Instr *lastNextInstr = lastInstr->m_next;
this->ToVar(lastNextInstr, newOpnd, block, nullptr, false);
}
} NEXT_BITSET_IN_SPARSEBV;
}
void
GlobOpt::ToInt32(BVSparse<JitArenaAllocator> *bv, BasicBlock *block, bool lossy, IR::Instr *insertBeforeInstr)
{
return this->ToTypeSpec(bv, block, TyInt32, IR::BailOutIntOnly, lossy, insertBeforeInstr);
}
void
GlobOpt::ToFloat64(BVSparse<JitArenaAllocator> *bv, BasicBlock *block)
{
return this->ToTypeSpec(bv, block, TyFloat64, IR::BailOutNumberOnly);
}
void
GlobOpt::ToTypeSpec(BVSparse<JitArenaAllocator> *bv, BasicBlock *block, IRType toType, IR::BailOutKind bailOutKind, bool lossy, IR::Instr *insertBeforeInstr)
{
FOREACH_BITSET_IN_SPARSEBV(id, bv)
{
StackSym *stackSym = this->func->m_symTable->FindStackSym(id);
IRType fromType = TyIllegal;
// Win8 bug: 757126. If we are trying to type specialize the arguments object,
// let's make sure stack args optimization is not enabled. This is a problem, particularly,
// if the instruction comes from an unreachable block. In other cases, the pass on the
// instruction itself should disable arguments object optimization.
if(block->globOptData.argObjSyms && block->globOptData.IsArgumentsSymID(id))
{
CannotAllocateArgumentsObjectOnStack();
}
if (block->globOptData.liveVarSyms->Test(id))
{
fromType = TyVar;
}
else if (block->globOptData.liveInt32Syms->Test(id) && !block->globOptData.liveLossyInt32Syms->Test(id))
{
fromType = TyInt32;
stackSym = stackSym->GetInt32EquivSym(this->func);
}
else if (block->globOptData.liveFloat64Syms->Test(id))
{
fromType = TyFloat64;
stackSym = stackSym->GetFloat64EquivSym(this->func);
}
else
{
Assert(UNREACHED);
}
IR::RegOpnd *newOpnd = IR::RegOpnd::New(stackSym, fromType, this->func);
this->ToTypeSpecUse(nullptr, newOpnd, block, nullptr, nullptr, toType, bailOutKind, lossy, insertBeforeInstr);
} NEXT_BITSET_IN_SPARSEBV;
}
void GlobOpt::PRE::FindPossiblePRECandidates(Loop *loop, JitArenaAllocator *alloc)
{
// Find the set of PRE candidates
BasicBlock *loopHeader = loop->GetHeadBlock();
PRECandidates *candidates = nullptr;
bool firstBackEdge = true;
FOREACH_PREDECESSOR_BLOCK(blockPred, loopHeader)
{
if (!loop->IsDescendentOrSelf(blockPred->loop))
{
// Not a loop back-edge
continue;
}
if (firstBackEdge)
{
candidates = this->globOpt->FindBackEdgePRECandidates(blockPred, alloc);
}
else
{
blockPred->globOptData.RemoveUnavailableCandidates(candidates);
}
} NEXT_PREDECESSOR_BLOCK;
this->candidates = candidates;
}
BOOL GlobOpt::PRE::PreloadPRECandidate(Loop *loop, GlobHashBucket* candidate)
{
// Insert a load for each field PRE candidate.
PropertySym *propertySym = candidate->value->AsPropertySym();
if (!candidates->candidatesToProcess->TestAndClear(propertySym->m_id))
{
return false;
}
Value * propSymValueOnBackEdge = candidate->element;
StackSym *objPtrSym = propertySym->m_stackSym;
Sym * objPtrCopyPropSym = nullptr;
if (!loop->landingPad->globOptData.IsLive(objPtrSym))
{
if (PHASE_OFF(Js::MakeObjSymLiveInLandingPadPhase, this->globOpt->func))
{
return false;
}
if (objPtrSym->IsSingleDef())
{
// We can still try to do PRE if the object sym is single def, even if its not live in the landing pad.
// We'll have to add a def instruction for the object sym in the landing pad, and then we can continue
// pre-loading the current PRE candidate.
// Case in point:
// $L1
// value|symStore
// t1 = o.x (v1|t3)
// t2 = t1.y (v2|t4) <-- t1 is not live in the loop landing pad
// jmp $L1
if (!InsertSymDefinitionInLandingPad(objPtrSym, loop, &objPtrCopyPropSym))
{
#if DBG_DUMP
TraceFailedPreloadInLandingPad(loop, propertySym, _u("Failed to insert load of object sym in landing pad"));
#endif
return false;
}
}
else
{
#if DBG_DUMP
TraceFailedPreloadInLandingPad(loop, propertySym, _u("Object sym not live in landing pad and not single-def"));
#endif
return false;
}
}
Assert(loop->landingPad->globOptData.IsLive(objPtrSym));
BasicBlock *landingPad = loop->landingPad;
Sym *symStore = propSymValueOnBackEdge->GetValueInfo()->GetSymStore();