blob: 419330a7889c1f249c1d4887bd6281b638a57696 [file] [log] [blame]
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "jit/MIR.h"
#include "mozilla/FloatingPoint.h"
#include "mozilla/IntegerPrintfMacros.h"
#include "mozilla/MathAlgorithms.h"
#include "mozilla/SizePrintfMacros.h"
#include <ctype.h>
#include "jslibmath.h"
#include "jsstr.h"
#include "jit/AtomicOperations.h"
#include "jit/BaselineInspector.h"
#include "jit/IonBuilder.h"
#include "jit/JitSpewer.h"
#include "jit/MIRGraph.h"
#include "jit/RangeAnalysis.h"
#include "js/Conversions.h"
#include "jsatominlines.h"
#include "jsobjinlines.h"
#include "jsscriptinlines.h"
using namespace js;
using namespace js::jit;
using JS::ToInt32;
using mozilla::NumbersAreIdentical;
using mozilla::IsFloat32Representable;
using mozilla::IsNaN;
using mozilla::Maybe;
using mozilla::DebugOnly;
#ifdef DEBUG
size_t MUse::index() const
{
return consumer()->indexOf(this);
}
#endif
template<size_t Op> static void
ConvertDefinitionToDouble(TempAllocator& alloc, MDefinition* def, MInstruction* consumer)
{
MInstruction* replace = MToDouble::New(alloc, def);
consumer->replaceOperand(Op, replace);
consumer->block()->insertBefore(consumer, replace);
}
static bool
CheckUsesAreFloat32Consumers(const MInstruction* ins)
{
bool allConsumerUses = true;
for (MUseDefIterator use(ins); allConsumerUses && use; use++)
allConsumerUses &= use.def()->canConsumeFloat32(use.use());
return allConsumerUses;
}
void
MDefinition::PrintOpcodeName(GenericPrinter& out, MDefinition::Opcode op)
{
static const char * const names[] =
{
#define NAME(x) #x,
MIR_OPCODE_LIST(NAME)
#undef NAME
};
const char* name = names[op];
size_t len = strlen(name);
for (size_t i = 0; i < len; i++)
out.printf("%c", tolower(name[i]));
}
const Value&
MDefinition::constantValue()
{
MOZ_ASSERT(isConstantValue());
if (isBox())
return getOperand(0)->constantValue();
return toConstant()->value();
}
const Value*
MDefinition::constantVp()
{
MOZ_ASSERT(isConstantValue());
if (isBox())
return getOperand(0)->constantVp();
return toConstant()->vp();
}
bool
MDefinition::constantToBoolean()
{
MOZ_ASSERT(isConstantValue());
if (isBox())
return getOperand(0)->constantToBoolean();
return toConstant()->valueToBoolean();
}
static MConstant*
EvaluateConstantOperands(TempAllocator& alloc, MBinaryInstruction* ins, bool* ptypeChange = nullptr)
{
MDefinition* left = ins->getOperand(0);
MDefinition* right = ins->getOperand(1);
MOZ_ASSERT(IsNumberType(left->type()) && IsNumberType(right->type()));
if (!left->isConstantValue() || !right->isConstantValue())
return nullptr;
Value lhs = left->constantValue();
Value rhs = right->constantValue();
Value ret = UndefinedValue();
switch (ins->op()) {
case MDefinition::Op_BitAnd:
ret = Int32Value(lhs.toInt32() & rhs.toInt32());
break;
case MDefinition::Op_BitOr:
ret = Int32Value(lhs.toInt32() | rhs.toInt32());
break;
case MDefinition::Op_BitXor:
ret = Int32Value(lhs.toInt32() ^ rhs.toInt32());
break;
case MDefinition::Op_Lsh:
ret = Int32Value(uint32_t(lhs.toInt32()) << (rhs.toInt32() & 0x1F));
break;
case MDefinition::Op_Rsh:
ret = Int32Value(lhs.toInt32() >> (rhs.toInt32() & 0x1F));
break;
case MDefinition::Op_Ursh:
ret.setNumber(uint32_t(lhs.toInt32()) >> (rhs.toInt32() & 0x1F));
break;
case MDefinition::Op_Add:
ret.setNumber(lhs.toNumber() + rhs.toNumber());
break;
case MDefinition::Op_Sub:
ret.setNumber(lhs.toNumber() - rhs.toNumber());
break;
case MDefinition::Op_Mul:
ret.setNumber(lhs.toNumber() * rhs.toNumber());
break;
case MDefinition::Op_Div:
if (ins->toDiv()->isUnsigned())
ret.setInt32(rhs.isInt32(0) ? 0 : uint32_t(lhs.toInt32()) / uint32_t(rhs.toInt32()));
else
ret.setNumber(NumberDiv(lhs.toNumber(), rhs.toNumber()));
break;
case MDefinition::Op_Mod:
if (ins->toMod()->isUnsigned())
ret.setInt32(rhs.isInt32(0) ? 0 : uint32_t(lhs.toInt32()) % uint32_t(rhs.toInt32()));
else
ret.setNumber(NumberMod(lhs.toNumber(), rhs.toNumber()));
break;
default:
MOZ_CRASH("NYI");
}
// setNumber eagerly transforms a number to int32.
// Transform back to double, if the output type is double.
if (ins->type() == MIRType_Double && ret.isInt32())
ret.setDouble(ret.toNumber());
if (ins->type() != MIRTypeFromValue(ret)) {
if (ptypeChange)
*ptypeChange = true;
return nullptr;
}
return MConstant::New(alloc, ret);
}
static MMul*
EvaluateExactReciprocal(TempAllocator& alloc, MDiv* ins)
{
// we should fold only when it is a floating point operation
if (!IsFloatingPointType(ins->type()))
return nullptr;
MDefinition* left = ins->getOperand(0);
MDefinition* right = ins->getOperand(1);
if (!right->isConstantValue())
return nullptr;
Value rhs = right->constantValue();
int32_t num;
if (!mozilla::NumberIsInt32(rhs.toNumber(), &num))
return nullptr;
// check if rhs is a power of two
if (mozilla::Abs(num) & (mozilla::Abs(num) - 1))
return nullptr;
Value ret;
ret.setDouble(1.0 / (double) num);
MConstant* foldedRhs = MConstant::New(alloc, ret);
foldedRhs->setResultType(ins->type());
ins->block()->insertBefore(ins, foldedRhs);
MMul* mul = MMul::New(alloc, left, foldedRhs, ins->type());
mul->setCommutative();
return mul;
}
void
MDefinition::printName(GenericPrinter& out) const
{
PrintOpcodeName(out, op());
out.printf("%u", id());
}
HashNumber
MDefinition::addU32ToHash(HashNumber hash, uint32_t data)
{
return data + (hash << 6) + (hash << 16) - hash;
}
HashNumber
MDefinition::valueHash() const
{
HashNumber out = op();
for (size_t i = 0, e = numOperands(); i < e; i++)
out = addU32ToHash(out, getOperand(i)->id());
if (MInstruction* dep = dependency())
out = addU32ToHash(out, dep->id());
return out;
}
bool
MDefinition::congruentIfOperandsEqual(const MDefinition* ins) const
{
if (op() != ins->op())
return false;
if (type() != ins->type())
return false;
if (isEffectful() || ins->isEffectful())
return false;
if (numOperands() != ins->numOperands())
return false;
for (size_t i = 0, e = numOperands(); i < e; i++) {
if (getOperand(i) != ins->getOperand(i))
return false;
}
return true;
}
MDefinition*
MDefinition::foldsTo(TempAllocator& alloc)
{
// In the default case, there are no constants to fold.
return this;
}
bool
MDefinition::mightBeMagicType() const
{
if (IsMagicType(type()))
return true;
if (MIRType_Value != type())
return false;
return !resultTypeSet() || resultTypeSet()->hasType(TypeSet::MagicArgType());
}
MDefinition*
MInstruction::foldsToStoredValue(TempAllocator& alloc, MDefinition* loaded)
{
// If the type are matching then we return the value which is used as
// argument of the store.
if (loaded->type() != type()) {
// If we expect to read a type which is more generic than the type seen
// by the store, then we box the value used by the store.
if (type() != MIRType_Value)
return this;
MOZ_ASSERT(loaded->type() < MIRType_Value);
MBox* box = MBox::New(alloc, loaded);
loaded = box;
}
return loaded;
}
void
MDefinition::analyzeEdgeCasesForward()
{
}
void
MDefinition::analyzeEdgeCasesBackward()
{
}
void
MInstruction::setResumePoint(MResumePoint* resumePoint)
{
MOZ_ASSERT(!resumePoint_);
resumePoint_ = resumePoint;
resumePoint_->setInstruction(this);
}
void
MInstruction::stealResumePoint(MInstruction* ins)
{
MOZ_ASSERT(ins->resumePoint_->instruction() == ins);
resumePoint_ = ins->resumePoint_;
ins->resumePoint_ = nullptr;
resumePoint_->replaceInstruction(this);
}
void
MInstruction::moveResumePointAsEntry()
{
MOZ_ASSERT(isNop());
block()->clearEntryResumePoint();
block()->setEntryResumePoint(resumePoint_);
resumePoint_->resetInstruction();
resumePoint_ = nullptr;
}
void
MInstruction::clearResumePoint()
{
resumePoint_->resetInstruction();
block()->discardPreAllocatedResumePoint(resumePoint_);
resumePoint_ = nullptr;
}
bool
MDefinition::maybeEmulatesUndefined(CompilerConstraintList* constraints)
{
if (!mightBeType(MIRType_Object))
return false;
TemporaryTypeSet* types = resultTypeSet();
if (!types)
return true;
return types->maybeEmulatesUndefined(constraints);
}
static bool
MaybeCallable(CompilerConstraintList* constraints, MDefinition* op)
{
if (!op->mightBeType(MIRType_Object))
return false;
TemporaryTypeSet* types = op->resultTypeSet();
if (!types)
return true;
return types->maybeCallable(constraints);
}
MTest*
MTest::New(TempAllocator& alloc, MDefinition* ins, MBasicBlock* ifTrue, MBasicBlock* ifFalse)
{
return new(alloc) MTest(ins, ifTrue, ifFalse);
}
void
MTest::cacheOperandMightEmulateUndefined(CompilerConstraintList* constraints)
{
MOZ_ASSERT(operandMightEmulateUndefined());
if (!getOperand(0)->maybeEmulatesUndefined(constraints))
markNoOperandEmulatesUndefined();
}
MDefinition*
MTest::foldsTo(TempAllocator& alloc)
{
MDefinition* op = getOperand(0);
if (op->isNot()) {
// If the operand of the Not is itself a Not, they cancel out.
MDefinition* opop = op->getOperand(0);
if (opop->isNot())
return MTest::New(alloc, opop->toNot()->input(), ifTrue(), ifFalse());
return MTest::New(alloc, op->toNot()->input(), ifFalse(), ifTrue());
}
if (op->isConstantValue() && !op->constantValue().isMagic())
return MGoto::New(alloc, op->constantToBoolean() ? ifTrue() : ifFalse());
switch (op->type()) {
case MIRType_Undefined:
case MIRType_Null:
return MGoto::New(alloc, ifFalse());
case MIRType_Symbol:
return MGoto::New(alloc, ifTrue());
case MIRType_Object:
if (!operandMightEmulateUndefined())
return MGoto::New(alloc, ifTrue());
break;
default:
break;
}
return this;
}
void
MTest::filtersUndefinedOrNull(bool trueBranch, MDefinition** subject, bool* filtersUndefined,
bool* filtersNull)
{
MDefinition* ins = getOperand(0);
if (ins->isCompare()) {
ins->toCompare()->filtersUndefinedOrNull(trueBranch, subject, filtersUndefined, filtersNull);
return;
}
if (!trueBranch && ins->isNot()) {
*subject = ins->getOperand(0);
*filtersUndefined = *filtersNull = true;
return;
}
if (trueBranch) {
*subject = ins;
*filtersUndefined = *filtersNull = true;
return;
}
*filtersUndefined = *filtersNull = false;
*subject = nullptr;
}
void
MDefinition::printOpcode(GenericPrinter& out) const
{
PrintOpcodeName(out, op());
for (size_t j = 0, e = numOperands(); j < e; j++) {
out.printf(" ");
if (getUseFor(j)->hasProducer())
getOperand(j)->printName(out);
else
out.printf("(null)");
}
}
void
MDefinition::dump(GenericPrinter& out) const
{
printName(out);
out.printf(" = ");
printOpcode(out);
out.printf("\n");
if (isInstruction()) {
if (MResumePoint* resume = toInstruction()->resumePoint())
resume->dump(out);
}
}
void
MDefinition::dump() const
{
Fprinter out(stderr);
dump(out);
out.finish();
}
void
MDefinition::dumpLocation(GenericPrinter& out) const
{
MResumePoint* rp = nullptr;
const char* linkWord = nullptr;
if (isInstruction() && toInstruction()->resumePoint()) {
rp = toInstruction()->resumePoint();
linkWord = "at";
} else {
rp = block()->entryResumePoint();
linkWord = "after";
}
while (rp) {
JSScript* script = rp->block()->info().script();
uint32_t lineno = PCToLineNumber(rp->block()->info().script(), rp->pc());
out.printf(" %s %s:%d\n", linkWord, script->filename(), lineno);
rp = rp->caller();
linkWord = "in";
}
}
void
MDefinition::dumpLocation() const
{
Fprinter out(stderr);
dumpLocation(out);
out.finish();
}
#if defined(DEBUG) || defined(JS_JITSPEW)
size_t
MDefinition::useCount() const
{
size_t count = 0;
for (MUseIterator i(uses_.begin()); i != uses_.end(); i++)
count++;
return count;
}
size_t
MDefinition::defUseCount() const
{
size_t count = 0;
for (MUseIterator i(uses_.begin()); i != uses_.end(); i++)
if ((*i)->consumer()->isDefinition())
count++;
return count;
}
#endif
bool
MDefinition::hasOneUse() const
{
MUseIterator i(uses_.begin());
if (i == uses_.end())
return false;
i++;
return i == uses_.end();
}
bool
MDefinition::hasOneDefUse() const
{
bool hasOneDefUse = false;
for (MUseIterator i(uses_.begin()); i != uses_.end(); i++) {
if (!(*i)->consumer()->isDefinition())
continue;
// We already have a definition use. So 1+
if (hasOneDefUse)
return false;
// We saw one definition. Loop to test if there is another.
hasOneDefUse = true;
}
return hasOneDefUse;
}
bool
MDefinition::hasDefUses() const
{
for (MUseIterator i(uses_.begin()); i != uses_.end(); i++) {
if ((*i)->consumer()->isDefinition())
return true;
}
return false;
}
bool
MDefinition::hasLiveDefUses() const
{
for (MUseIterator i(uses_.begin()); i != uses_.end(); i++) {
MNode* ins = (*i)->consumer();
if (ins->isDefinition()) {
if (!ins->toDefinition()->isRecoveredOnBailout())
return true;
} else {
MOZ_ASSERT(ins->isResumePoint());
if (!ins->toResumePoint()->isRecoverableOperand(*i))
return true;
}
}
return false;
}
void
MDefinition::replaceAllUsesWith(MDefinition* dom)
{
for (size_t i = 0, e = numOperands(); i < e; ++i)
getOperand(i)->setUseRemovedUnchecked();
justReplaceAllUsesWith(dom);
}
void
MDefinition::justReplaceAllUsesWith(MDefinition* dom)
{
MOZ_ASSERT(dom != nullptr);
MOZ_ASSERT(dom != this);
// Carry over the fact the value has uses which are no longer inspectable
// with the graph.
if (isUseRemoved())
dom->setUseRemovedUnchecked();
for (MUseIterator i(usesBegin()), e(usesEnd()); i != e; ++i)
i->setProducerUnchecked(dom);
dom->uses_.takeElements(uses_);
}
void
MDefinition::justReplaceAllUsesWithExcept(MDefinition* dom)
{
MOZ_ASSERT(dom != nullptr);
MOZ_ASSERT(dom != this);
// Carry over the fact the value has uses which are no longer inspectable
// with the graph.
if (isUseRemoved())
dom->setUseRemovedUnchecked();
// Move all uses to new dom. Save the use of the dominating instruction.
MUse *exceptUse = nullptr;
for (MUseIterator i(usesBegin()), e(usesEnd()); i != e; ++i) {
if (i->consumer() != dom) {
i->setProducerUnchecked(dom);
} else {
MOZ_ASSERT(!exceptUse);
exceptUse = *i;
}
}
dom->uses_.takeElements(uses_);
// Restore the use to the original definition.
dom->uses_.remove(exceptUse);
exceptUse->setProducerUnchecked(this);
uses_.pushFront(exceptUse);
}
void
MDefinition::optimizeOutAllUses(TempAllocator& alloc)
{
for (MUseIterator i(usesBegin()), e(usesEnd()); i != e;) {
MUse* use = *i++;
MConstant* constant = use->consumer()->block()->optimizedOutConstant(alloc);
// Update the resume point operand to use the optimized-out constant.
use->setProducerUnchecked(constant);
constant->addUseUnchecked(use);
}
// Remove dangling pointers.
this->uses_.clear();
}
void
MDefinition::replaceAllLiveUsesWith(MDefinition* dom)
{
for (MUseIterator i(usesBegin()), e(usesEnd()); i != e; ) {
MUse* use = *i++;
MNode* consumer = use->consumer();
if (consumer->isResumePoint())
continue;
if (consumer->isDefinition() && consumer->toDefinition()->isRecoveredOnBailout())
continue;
// Update the operand to use the dominating definition.
use->replaceProducer(dom);
}
}
bool
MDefinition::emptyResultTypeSet() const
{
return resultTypeSet() && resultTypeSet()->empty();
}
MConstant*
MConstant::New(TempAllocator& alloc, const Value& v, CompilerConstraintList* constraints)
{
return new(alloc) MConstant(v, constraints);
}
MConstant*
MConstant::NewTypedValue(TempAllocator& alloc, const Value& v, MIRType type,
CompilerConstraintList* constraints)
{
MOZ_ASSERT(!IsSimdType(type));
MOZ_ASSERT_IF(type == MIRType_Float32,
IsNaN(v.toDouble()) || v.toDouble() == double(float(v.toDouble())));
MConstant* constant = new(alloc) MConstant(v, constraints);
constant->setResultType(type);
return constant;
}
MConstant*
MConstant::NewAsmJS(TempAllocator& alloc, const Value& v, MIRType type)
{
if (type == MIRType_Float32)
return NewTypedValue(alloc, Float32Value(v.toNumber()), type);
return NewTypedValue(alloc, v, type);
}
MConstant*
MConstant::NewConstraintlessObject(TempAllocator& alloc, JSObject* v)
{
return new(alloc) MConstant(v);
}
static TemporaryTypeSet*
MakeSingletonTypeSetFromKey(CompilerConstraintList* constraints, TypeSet::ObjectKey* key)
{
// Invalidate when this object's ObjectGroup gets unknown properties. This
// happens for instance when we mutate an object's __proto__, in this case
// we want to invalidate and mark this TypeSet as containing AnyObject
// (because mutating __proto__ will change an object's ObjectGroup).
MOZ_ASSERT(constraints);
key->hasStableClassAndProto(constraints);
LifoAlloc* alloc = GetJitContext()->temp->lifoAlloc();
return alloc->new_<TemporaryTypeSet>(alloc, TypeSet::ObjectType(key));
}
TemporaryTypeSet*
jit::MakeSingletonTypeSet(CompilerConstraintList* constraints, JSObject* obj)
{
return MakeSingletonTypeSetFromKey(constraints, TypeSet::ObjectKey::get(obj));
}
TemporaryTypeSet*
jit::MakeSingletonTypeSet(CompilerConstraintList* constraints, ObjectGroup* obj)
{
return MakeSingletonTypeSetFromKey(constraints, TypeSet::ObjectKey::get(obj));
}
static TemporaryTypeSet*
MakeUnknownTypeSet()
{
LifoAlloc* alloc = GetJitContext()->temp->lifoAlloc();
return alloc->new_<TemporaryTypeSet>(alloc, TypeSet::UnknownType());
}
#ifdef DEBUG
bool
jit::IonCompilationCanUseNurseryPointers()
{
// If we are doing backend compilation, which could occur on a helper
// thread but might actually be on the main thread, check the flag set on
// the PerThreadData by AutoEnterIonCompilation.
if (CurrentThreadIsIonCompiling())
return !CurrentThreadIsIonCompilingSafeForMinorGC();
// Otherwise, we must be on the main thread during MIR construction. The
// store buffer must have been notified that minor GCs must cancel pending
// or in progress Ion compilations.
JSRuntime* rt = TlsPerThreadData.get()->runtimeFromMainThread();
return rt->gc.storeBuffer.cancelIonCompilations();
}
#endif // DEBUG
MConstant::MConstant(const js::Value& vp, CompilerConstraintList* constraints)
: value_(vp)
{
setResultType(MIRTypeFromValue(vp));
if (vp.isObject()) {
// Create a singleton type set for the object. This isn't necessary for
// other types as the result type encodes all needed information.
MOZ_ASSERT_IF(IsInsideNursery(&vp.toObject()), IonCompilationCanUseNurseryPointers());
setResultTypeSet(MakeSingletonTypeSet(constraints, &vp.toObject()));
}
if (vp.isMagic() && vp.whyMagic() == JS_UNINITIALIZED_LEXICAL) {
// JS_UNINITIALIZED_LEXICAL does not escape to script and is not
// observed in type sets. However, it may flow around freely during
// Ion compilation. Give it an unknown typeset to poison any type sets
// it merges with.
//
// TODO We could track uninitialized lexicals more precisely by tracking
// them in type sets.
setResultTypeSet(MakeUnknownTypeSet());
}
MOZ_ASSERT_IF(vp.isString(), vp.toString()->isAtom());
setMovable();
}
MConstant::MConstant(JSObject* obj)
: value_(ObjectValue(*obj))
{
MOZ_ASSERT_IF(IsInsideNursery(obj), IonCompilationCanUseNurseryPointers());
setResultType(MIRType_Object);
setMovable();
}
HashNumber
MConstant::valueHash() const
{
// Fold all 64 bits into the 32-bit result. It's tempting to just discard
// half of the bits, as this is just a hash, however there are many common
// patterns of values where only the low or the high bits vary, so
// discarding either side would lead to excessive hash collisions.
uint64_t bits = JSVAL_TO_IMPL(value_).asBits;
return (HashNumber)bits ^ (HashNumber)(bits >> 32);
}
bool
MConstant::congruentTo(const MDefinition* ins) const
{
if (!ins->isConstant())
return false;
return ins->toConstant()->value() == value();
}
void
MConstant::printOpcode(GenericPrinter& out) const
{
PrintOpcodeName(out, op());
out.printf(" ");
switch (type()) {
case MIRType_Undefined:
out.printf("undefined");
break;
case MIRType_Null:
out.printf("null");
break;
case MIRType_Boolean:
out.printf(value().toBoolean() ? "true" : "false");
break;
case MIRType_Int32:
out.printf("0x%x", value().toInt32());
break;
case MIRType_Double:
out.printf("%.16g", value().toDouble());
break;
case MIRType_Float32:
{
float val = value().toDouble();
out.printf("%.16g", val);
break;
}
case MIRType_Object:
if (value().toObject().is<JSFunction>()) {
JSFunction* fun = &value().toObject().as<JSFunction>();
if (fun->displayAtom()) {
out.put("function ");
EscapedStringPrinter(out, fun->displayAtom(), 0);
} else {
out.put("unnamed function");
}
if (fun->hasScript()) {
JSScript* script = fun->nonLazyScript();
out.printf(" (%s:%" PRIuSIZE ")",
script->filename() ? script->filename() : "", script->lineno());
}
out.printf(" at %p", (void*) fun);
break;
}
out.printf("object %p (%s)", (void*)&value().toObject(),
value().toObject().getClass()->name);
break;
case MIRType_Symbol:
out.printf("symbol at %p", (void*)value().toSymbol());
break;
case MIRType_String:
out.printf("string %p", (void*)value().toString());
break;
case MIRType_MagicOptimizedArguments:
out.printf("magic lazyargs");
break;
case MIRType_MagicHole:
out.printf("magic hole");
break;
case MIRType_MagicIsConstructing:
out.printf("magic is-constructing");
break;
case MIRType_MagicOptimizedOut:
out.printf("magic optimized-out");
break;
case MIRType_MagicUninitializedLexical:
out.printf("magic uninitialized-lexical");
break;
default:
MOZ_CRASH("unexpected type");
}
}
bool
MConstant::canProduceFloat32() const
{
if (!IsNumberType(type()))
return false;
if (type() == MIRType_Int32)
return IsFloat32Representable(static_cast<double>(value_.toInt32()));
if (type() == MIRType_Double)
return IsFloat32Representable(value_.toDouble());
return true;
}
MDefinition*
MSimdValueX4::foldsTo(TempAllocator& alloc)
{
DebugOnly<MIRType> laneType = SimdTypeToLaneType(type());
bool allConstants = true;
bool allSame = true;
for (size_t i = 0; i < 4; ++i) {
MDefinition* op = getOperand(i);
MOZ_ASSERT(op->type() == laneType);
if (!op->isConstantValue())
allConstants = false;
if (i > 0 && op != getOperand(i - 1))
allSame = false;
}
if (!allConstants && !allSame)
return this;
if (allConstants) {
SimdConstant cst;
switch (type()) {
case MIRType_Int32x4: {
int32_t a[4];
for (size_t i = 0; i < 4; ++i)
a[i] = getOperand(i)->constantValue().toInt32();
cst = SimdConstant::CreateX4(a);
break;
}
case MIRType_Float32x4: {
float a[4];
for (size_t i = 0; i < 4; ++i)
a[i] = getOperand(i)->constantValue().toNumber();
cst = SimdConstant::CreateX4(a);
break;
}
default: MOZ_CRASH("unexpected type in MSimdValueX4::foldsTo");
}
return MSimdConstant::New(alloc, cst, type());
}
MOZ_ASSERT(allSame);
return MSimdSplatX4::New(alloc, getOperand(0), type());
}
MDefinition*
MSimdSplatX4::foldsTo(TempAllocator& alloc)
{
DebugOnly<MIRType> laneType = SimdTypeToLaneType(type());
MDefinition* op = getOperand(0);
if (!op->isConstantValue())
return this;
MOZ_ASSERT(op->type() == laneType);
SimdConstant cst;
switch (type()) {
case MIRType_Int32x4: {
int32_t a[4];
int32_t v = getOperand(0)->constantValue().toInt32();
for (size_t i = 0; i < 4; ++i)
a[i] = v;
cst = SimdConstant::CreateX4(a);
break;
}
case MIRType_Float32x4: {
float a[4];
float v = getOperand(0)->constantValue().toNumber();
for (size_t i = 0; i < 4; ++i)
a[i] = v;
cst = SimdConstant::CreateX4(a);
break;
}
default: MOZ_CRASH("unexpected type in MSimdSplatX4::foldsTo");
}
return MSimdConstant::New(alloc, cst, type());
}
MDefinition*
MSimdUnbox::foldsTo(TempAllocator& alloc)
{
MDefinition* in = input();
if (in->isSimdBox()) {
// If the operand is a MSimdBox, then we just reuse the operand of the
// MSimdBox as long as the type corresponds to what we are supposed to
// unbox.
in = in->toSimdBox()->input();
if (in->type() != type())
return this;
return in;
}
return this;
}
MDefinition*
MSimdSwizzle::foldsTo(TempAllocator& alloc)
{
if (lanesMatch(0, 1, 2, 3))
return input();
return this;
}
MDefinition*
MSimdGeneralShuffle::foldsTo(TempAllocator& alloc)
{
FixedList<uint32_t> lanes;
if (!lanes.init(alloc, numLanes()))
return this;
for (size_t i = 0; i < numLanes(); i++) {
if (!lane(i)->isConstant() || lane(i)->type() != MIRType_Int32)
return this;
int32_t temp = lane(i)->toConstant()->value().toInt32();
if (temp < 0 || uint32_t(temp) >= numLanes() * numVectors())
return this;
lanes[i] = uint32_t(temp);
}
if (numVectors() == 1)
return MSimdSwizzle::New(alloc, vector(0), type(), lanes[0], lanes[1], lanes[2], lanes[3]);
MOZ_ASSERT(numVectors() == 2);
return MSimdShuffle::New(alloc, vector(0), vector(1), type(), lanes[0], lanes[1], lanes[2], lanes[3]);
}
template <typename T>
static void
PrintOpcodeOperation(T* mir, GenericPrinter& out)
{
mir->MDefinition::printOpcode(out);
out.printf(" (%s)", T::OperationName(mir->operation()));
}
void
MSimdBinaryArith::printOpcode(GenericPrinter& out) const
{
PrintOpcodeOperation(this, out);
}
void
MSimdBinaryBitwise::printOpcode(GenericPrinter& out) const
{
PrintOpcodeOperation(this, out);
}
void
MSimdUnaryArith::printOpcode(GenericPrinter& out) const
{
PrintOpcodeOperation(this, out);
}
void
MSimdBinaryComp::printOpcode(GenericPrinter& out) const
{
PrintOpcodeOperation(this, out);
}
void
MSimdShift::printOpcode(GenericPrinter& out) const
{
PrintOpcodeOperation(this, out);
}
void
MSimdInsertElement::printOpcode(GenericPrinter& out) const
{
MDefinition::printOpcode(out);
out.printf(" (%s)", MSimdInsertElement::LaneName(lane()));
}
MCloneLiteral*
MCloneLiteral::New(TempAllocator& alloc, MDefinition* obj)
{
return new(alloc) MCloneLiteral(obj);
}
void
MControlInstruction::printOpcode(GenericPrinter& out) const
{
MDefinition::printOpcode(out);
for (size_t j = 0; j < numSuccessors(); j++)
out.printf(" block%u", getSuccessor(j)->id());
}
void
MCompare::printOpcode(GenericPrinter& out) const
{
MDefinition::printOpcode(out);
out.printf(" %s", CodeName[jsop()]);
}
void
MConstantElements::printOpcode(GenericPrinter& out) const
{
PrintOpcodeName(out, op());
out.printf(" 0x%" PRIxPTR, value().asValue());
}
void
MLoadUnboxedScalar::printOpcode(GenericPrinter& out) const
{
MDefinition::printOpcode(out);
out.printf(" %s", ScalarTypeDescr::typeName(storageType()));
}
void
MAssertRange::printOpcode(GenericPrinter& out) const
{
MDefinition::printOpcode(out);
out.put(" ");
assertedRange()->dump(out);
}
const char*
MMathFunction::FunctionName(Function function)
{
switch (function) {
case Log: return "Log";
case Sin: return "Sin";
case Cos: return "Cos";
case Exp: return "Exp";
case Tan: return "Tan";
case ACos: return "ACos";
case ASin: return "ASin";
case ATan: return "ATan";
case Log10: return "Log10";
case Log2: return "Log2";
case Log1P: return "Log1P";
case ExpM1: return "ExpM1";
case CosH: return "CosH";
case SinH: return "SinH";
case TanH: return "TanH";
case ACosH: return "ACosH";
case ASinH: return "ASinH";
case ATanH: return "ATanH";
case Sign: return "Sign";
case Trunc: return "Trunc";
case Cbrt: return "Cbrt";
case Floor: return "Floor";
case Ceil: return "Ceil";
case Round: return "Round";
default:
MOZ_CRASH("Unknown math function");
}
}
void
MMathFunction::printOpcode(GenericPrinter& out) const
{
MDefinition::printOpcode(out);
out.printf(" %s", FunctionName(function()));
}
MDefinition*
MMathFunction::foldsTo(TempAllocator& alloc)
{
MDefinition* input = getOperand(0);
if (!input->isConstant())
return this;
Value val = input->toConstant()->value();
if (!val.isNumber())
return this;
double in = val.toNumber();
double out;
switch (function_) {
case Log:
out = js::math_log_uncached(in);
break;
case Sin:
out = js::math_sin_uncached(in);
break;
case Cos:
out = js::math_cos_uncached(in);
break;
case Exp:
out = js::math_exp_uncached(in);
break;
case Tan:
out = js::math_tan_uncached(in);
break;
case ACos:
out = js::math_acos_uncached(in);
break;
case ASin:
out = js::math_asin_uncached(in);
break;
case ATan:
out = js::math_atan_uncached(in);
break;
case Log10:
out = js::math_log10_uncached(in);
break;
case Log2:
out = js::math_log2_uncached(in);
break;
case Log1P:
out = js::math_log1p_uncached(in);
break;
case ExpM1:
out = js::math_expm1_uncached(in);
break;
case CosH:
out = js::math_cosh_uncached(in);
break;
case SinH:
out = js::math_sinh_uncached(in);
break;
case TanH:
out = js::math_tanh_uncached(in);
break;
case ACosH:
out = js::math_acosh_uncached(in);
break;
case ASinH:
out = js::math_asinh_uncached(in);
break;
case ATanH:
out = js::math_atanh_uncached(in);
break;
case Sign:
out = js::math_sign_uncached(in);
break;
case Trunc:
out = js::math_trunc_uncached(in);
break;
case Cbrt:
out = js::math_cbrt_uncached(in);
break;
case Floor:
out = js::math_floor_impl(in);
break;
case Ceil:
out = js::math_ceil_impl(in);
break;
case Round:
out = js::math_round_impl(in);
break;
default:
return this;
}
if (input->type() == MIRType_Float32)
return MConstant::NewTypedValue(alloc, DoubleValue(out), MIRType_Float32);
return MConstant::New(alloc, DoubleValue(out));
}
MDefinition*
MAtomicIsLockFree::foldsTo(TempAllocator& alloc)
{
MDefinition* input = getOperand(0);
if (!input->isConstantValue())
return this;
Value val = input->constantValue();
if (!val.isInt32())
return this;
return MConstant::New(alloc, BooleanValue(AtomicOperations::isLockfree(val.toInt32())));
}
MParameter*
MParameter::New(TempAllocator& alloc, int32_t index, TemporaryTypeSet* types)
{
return new(alloc) MParameter(index, types);
}
void
MParameter::printOpcode(GenericPrinter& out) const
{
PrintOpcodeName(out, op());
if (index() == THIS_SLOT)
out.printf(" THIS_SLOT");
else
out.printf(" %d", index());
}
HashNumber
MParameter::valueHash() const
{
HashNumber hash = MDefinition::valueHash();
hash = addU32ToHash(hash, index_);
return hash;
}
bool
MParameter::congruentTo(const MDefinition* ins) const
{
if (!ins->isParameter())
return false;
return ins->toParameter()->index() == index_;
}
MCall*
MCall::New(TempAllocator& alloc, JSFunction* target, size_t maxArgc, size_t numActualArgs,
bool construct, bool isDOMCall)
{
MOZ_ASSERT(maxArgc >= numActualArgs);
MCall* ins;
if (isDOMCall) {
MOZ_ASSERT(!construct);
ins = new(alloc) MCallDOMNative(target, numActualArgs);
} else {
ins = new(alloc) MCall(target, numActualArgs, construct);
}
if (!ins->init(alloc, maxArgc + NumNonArgumentOperands))
return nullptr;
return ins;
}
AliasSet
MCallDOMNative::getAliasSet() const
{
const JSJitInfo* jitInfo = getJitInfo();
// If we don't know anything about the types of our arguments, we have to
// assume that type-coercions can have side-effects, so we need to alias
// everything.
if (jitInfo->aliasSet() == JSJitInfo::AliasEverything || !jitInfo->isTypedMethodJitInfo())
return AliasSet::Store(AliasSet::Any);
uint32_t argIndex = 0;
const JSTypedMethodJitInfo* methodInfo =
reinterpret_cast<const JSTypedMethodJitInfo*>(jitInfo);
for (const JSJitInfo::ArgType* argType = methodInfo->argTypes;
*argType != JSJitInfo::ArgTypeListEnd;
++argType, ++argIndex)
{
if (argIndex >= numActualArgs()) {
// Passing through undefined can't have side-effects
continue;
}
// getArg(0) is "this", so skip it
MDefinition* arg = getArg(argIndex+1);
MIRType actualType = arg->type();
// The only way to reliably avoid side-effects given the information we
// have here is if we're passing in a known primitive value to an
// argument that expects a primitive value.
//
// XXXbz maybe we need to communicate better information. For example,
// a sequence argument will sort of unavoidably have side effects, while
// a typed array argument won't have any, but both are claimed to be
// JSJitInfo::Object. But if we do that, we need to watch out for our
// movability/DCE-ability bits: if we have an arg type that can reliably
// throw an exception on conversion, that might not affect our alias set
// per se, but it should prevent us being moved or DCE-ed, unless we
// know the incoming things match that arg type and won't throw.
//
if ((actualType == MIRType_Value || actualType == MIRType_Object) ||
(*argType & JSJitInfo::Object))
{
return AliasSet::Store(AliasSet::Any);
}
}
// We checked all the args, and they check out. So we only alias DOM
// mutations or alias nothing, depending on the alias set in the jitinfo.
if (jitInfo->aliasSet() == JSJitInfo::AliasNone)
return AliasSet::None();
MOZ_ASSERT(jitInfo->aliasSet() == JSJitInfo::AliasDOMSets);
return AliasSet::Load(AliasSet::DOMProperty);
}
void
MCallDOMNative::computeMovable()
{
// We are movable if the jitinfo says we can be and if we're also not
// effectful. The jitinfo can't check for the latter, since it depends on
// the types of our arguments.
const JSJitInfo* jitInfo = getJitInfo();
MOZ_ASSERT_IF(jitInfo->isMovable,
jitInfo->aliasSet() != JSJitInfo::AliasEverything);
if (jitInfo->isMovable && !isEffectful())
setMovable();
}
bool
MCallDOMNative::congruentTo(const MDefinition* ins) const
{
if (!isMovable())
return false;
if (!ins->isCall())
return false;
const MCall* call = ins->toCall();
if (!call->isCallDOMNative())
return false;
if (getSingleTarget() != call->getSingleTarget())
return false;
if (isConstructing() != call->isConstructing())
return false;
if (numActualArgs() != call->numActualArgs())
return false;
if (needsArgCheck() != call->needsArgCheck())
return false;
if (!congruentIfOperandsEqual(call))
return false;
// The other call had better be movable at this point!
MOZ_ASSERT(call->isMovable());
return true;
}
const JSJitInfo*
MCallDOMNative::getJitInfo() const
{
MOZ_ASSERT(getSingleTarget() && getSingleTarget()->isNative());
const JSJitInfo* jitInfo = getSingleTarget()->jitInfo();
MOZ_ASSERT(jitInfo);
return jitInfo;
}
MApplyArgs*
MApplyArgs::New(TempAllocator& alloc, JSFunction* target, MDefinition* fun, MDefinition* argc,
MDefinition* self)
{
return new(alloc) MApplyArgs(target, fun, argc, self);
}
MApplyArray*
MApplyArray::New(TempAllocator& alloc, JSFunction* target, MDefinition* fun, MDefinition* elements,
MDefinition* self)
{
return new(alloc) MApplyArray(target, fun, elements, self);
}
MDefinition*
MStringLength::foldsTo(TempAllocator& alloc)
{
if ((type() == MIRType_Int32) && (string()->isConstantValue())) {
Value value = string()->constantValue();
JSAtom* atom = &value.toString()->asAtom();
return MConstant::New(alloc, Int32Value(atom->length()));
}
return this;
}
MDefinition*
MConcat::foldsTo(TempAllocator& alloc)
{
if (lhs()->isConstantValue() && lhs()->constantValue().toString()->empty())
return rhs();
if (rhs()->isConstantValue() && rhs()->constantValue().toString()->empty())
return lhs();
return this;
}
static bool
EnsureFloatInputOrConvert(MUnaryInstruction* owner, TempAllocator& alloc)
{
MDefinition* input = owner->input();
if (!input->canProduceFloat32()) {
if (input->type() == MIRType_Float32)
ConvertDefinitionToDouble<0>(alloc, input, owner);
return false;
}
return true;
}
void
MFloor::trySpecializeFloat32(TempAllocator& alloc)
{
MOZ_ASSERT(type() == MIRType_Int32);
if (EnsureFloatInputOrConvert(this, alloc))
specialization_ = MIRType_Float32;
}
void
MCeil::trySpecializeFloat32(TempAllocator& alloc)
{
MOZ_ASSERT(type() == MIRType_Int32);
if (EnsureFloatInputOrConvert(this, alloc))
specialization_ = MIRType_Float32;
}
void
MRound::trySpecializeFloat32(TempAllocator& alloc)
{
MOZ_ASSERT(type() == MIRType_Int32);
if (EnsureFloatInputOrConvert(this, alloc))
specialization_ = MIRType_Float32;
}
MCompare*
MCompare::New(TempAllocator& alloc, MDefinition* left, MDefinition* right, JSOp op)
{
return new(alloc) MCompare(left, right, op);
}
MCompare*
MCompare::NewAsmJS(TempAllocator& alloc, MDefinition* left, MDefinition* right, JSOp op,
CompareType compareType)
{
MOZ_ASSERT(compareType == Compare_Int32 || compareType == Compare_UInt32 ||
compareType == Compare_Double || compareType == Compare_Float32);
MCompare* comp = new(alloc) MCompare(left, right, op);
comp->compareType_ = compareType;
comp->operandMightEmulateUndefined_ = false;
comp->setResultType(MIRType_Int32);
return comp;
}
MTableSwitch*
MTableSwitch::New(TempAllocator& alloc, MDefinition* ins, int32_t low, int32_t high)
{
return new(alloc) MTableSwitch(alloc, ins, low, high);
}
MGoto*
MGoto::New(TempAllocator& alloc, MBasicBlock* target)
{
MOZ_ASSERT(target);
return new(alloc) MGoto(target);
}
void
MUnbox::printOpcode(GenericPrinter& out) const
{
PrintOpcodeName(out, op());
out.printf(" ");
getOperand(0)->printName(out);
out.printf(" ");
switch (type()) {
case MIRType_Int32: out.printf("to Int32"); break;
case MIRType_Double: out.printf("to Double"); break;
case MIRType_Boolean: out.printf("to Boolean"); break;
case MIRType_String: out.printf("to String"); break;
case MIRType_Symbol: out.printf("to Symbol"); break;
case MIRType_Object: out.printf("to Object"); break;
default: break;
}
switch (mode()) {
case Fallible: out.printf(" (fallible)"); break;
case Infallible: out.printf(" (infallible)"); break;
case TypeBarrier: out.printf(" (typebarrier)"); break;
default: break;
}
}
MDefinition*
MUnbox::foldsTo(TempAllocator &alloc)
{
if (!input()->isLoadFixedSlot())
return this;
MLoadFixedSlot* load = input()->toLoadFixedSlot();
if (load->type() != MIRType_Value)
return this;
if (type() != MIRType_Boolean && !IsNumberType(type()))
return this;
// Only optimize if the load comes immediately before the unbox, so it's
// safe to copy the load's dependency field.
MInstructionIterator iter(load->block()->begin(load));
++iter;
if (*iter != this)
return this;
MLoadFixedSlotAndUnbox* ins = MLoadFixedSlotAndUnbox::New(alloc, load->object(), load->slot(),
mode(), type(), bailoutKind());
// As GVN runs after the Alias Analysis, we have to set the dependency by hand
ins->setDependency(load->dependency());
return ins;
}
void
MTypeBarrier::printOpcode(GenericPrinter& out) const
{
PrintOpcodeName(out, op());
out.printf(" ");
getOperand(0)->printName(out);
}
bool
MTypeBarrier::congruentTo(const MDefinition* def) const
{
if (!def->isTypeBarrier())
return false;
const MTypeBarrier* other = def->toTypeBarrier();
if (barrierKind() != other->barrierKind() || isGuard() != other->isGuard())
return false;
if (!resultTypeSet()->equals(other->resultTypeSet()))
return false;
return congruentIfOperandsEqual(other);
}
#ifdef DEBUG
void
MPhi::assertLoopPhi() const
{
// getLoopPredecessorOperand and getLoopBackedgeOperand rely on these
// predecessors being at indices 0 and 1.
MBasicBlock* pred = block()->getPredecessor(0);
MBasicBlock* back = block()->getPredecessor(1);
MOZ_ASSERT(pred == block()->loopPredecessor());
MOZ_ASSERT(pred->successorWithPhis() == block());
MOZ_ASSERT(pred->positionInPhiSuccessor() == 0);
MOZ_ASSERT(back == block()->backedge());
MOZ_ASSERT(back->successorWithPhis() == block());
MOZ_ASSERT(back->positionInPhiSuccessor() == 1);
}
#endif
void
MPhi::removeOperand(size_t index)
{
MOZ_ASSERT(index < numOperands());
MOZ_ASSERT(getUseFor(index)->index() == index);
MOZ_ASSERT(getUseFor(index)->consumer() == this);
// If we have phi(..., a, b, c, d, ..., z) and we plan
// on removing a, then first shift downward so that we have
// phi(..., b, c, d, ..., z, z):
MUse* p = inputs_.begin() + index;
MUse* e = inputs_.end();
p->producer()->removeUse(p);
for (; p < e - 1; ++p) {
MDefinition* producer = (p + 1)->producer();
p->setProducerUnchecked(producer);
producer->replaceUse(p + 1, p);
}
// truncate the inputs_ list:
inputs_.popBack();
}
void
MPhi::removeAllOperands()
{
for (MUse& p : inputs_)
p.producer()->removeUse(&p);
inputs_.clear();
}
MDefinition*
MPhi::foldsTernary()
{
/* Look if this MPhi is a ternary construct.
* This is a very loose term as it actually only checks for
*
* MTest X
* / \
* ... ...
* \ /
* MPhi X Y
*
* Which we will simply call:
* x ? x : y or x ? y : x
*/
if (numOperands() != 2)
return nullptr;
MOZ_ASSERT(block()->numPredecessors() == 2);
MBasicBlock* pred = block()->immediateDominator();
if (!pred || !pred->lastIns()->isTest())
return nullptr;
MTest* test = pred->lastIns()->toTest();
// True branch may only dominate one edge of MPhi.
if (test->ifTrue()->dominates(block()->getPredecessor(0)) ==
test->ifTrue()->dominates(block()->getPredecessor(1)))
{
return nullptr;
}
// False branch may only dominate one edge of MPhi.
if (test->ifFalse()->dominates(block()->getPredecessor(0)) ==
test->ifFalse()->dominates(block()->getPredecessor(1)))
{
return nullptr;
}
// True and false branch must dominate different edges of MPhi.
if (test->ifTrue()->dominates(block()->getPredecessor(0)) ==
test->ifFalse()->dominates(block()->getPredecessor(0)))
{
return nullptr;
}
// We found a ternary construct.
bool firstIsTrueBranch = test->ifTrue()->dominates(block()->getPredecessor(0));
MDefinition* trueDef = firstIsTrueBranch ? getOperand(0) : getOperand(1);
MDefinition* falseDef = firstIsTrueBranch ? getOperand(1) : getOperand(0);
// Accept either
// testArg ? testArg : constant or
// testArg ? constant : testArg
if (!trueDef->isConstant() && !falseDef->isConstant())
return nullptr;
MConstant* c = trueDef->isConstant() ? trueDef->toConstant() : falseDef->toConstant();
MDefinition* testArg = (trueDef == c) ? falseDef : trueDef;
if (testArg != test->input())
return nullptr;
// This check should be a tautology, except that the constant might be the
// result of the removal of a branch. In such case the domination scope of
// the block which is holding the constant might be incomplete. This
// condition is used to prevent doing this optimization based on incomplete
// information.
//
// As GVN removed a branch, it will update the dominations rules before
// trying to fold this MPhi again. Thus, this condition does not inhibit
// this optimization.
MBasicBlock* truePred = block()->getPredecessor(firstIsTrueBranch ? 0 : 1);
MBasicBlock* falsePred = block()->getPredecessor(firstIsTrueBranch ? 1 : 0);
if (!trueDef->block()->dominates(truePred) ||
!falseDef->block()->dominates(falsePred))
{
return nullptr;
}
// If testArg is an int32 type we can:
// - fold testArg ? testArg : 0 to testArg
// - fold testArg ? 0 : testArg to 0
if (testArg->type() == MIRType_Int32 && c->vp()->toNumber() == 0) {
// When folding to the constant we need to hoist it.
if (trueDef == c && !c->block()->dominates(block()))
c->block()->moveBefore(pred->lastIns(), c);
return trueDef;
}
// If testArg is a string type we can:
// - fold testArg ? testArg : "" to testArg
// - fold testArg ? "" : testArg to ""
if (testArg->type() == MIRType_String &&
c->vp()->toString() == GetJitContext()->runtime->emptyString())
{
// When folding to the constant we need to hoist it.
if (trueDef == c && !c->block()->dominates(block()))
c->block()->moveBefore(pred->lastIns(), c);
return trueDef;
}
return nullptr;
}
MDefinition*
MPhi::operandIfRedundant()
{
if (inputs_.length() == 0)
return nullptr;
// If this phi is redundant (e.g., phi(a,a) or b=phi(a,this)),
// returns the operand that it will always be equal to (a, in
// those two cases).
MDefinition* first = getOperand(0);
for (size_t i = 1, e = numOperands(); i < e; i++) {
MDefinition* op = getOperand(i);
if (op != first && op != this)
return nullptr;
}
return first;
}
MDefinition*
MPhi::foldsFilterTypeSet()
{
// Fold phi with as operands a combination of 'subject' and
// MFilterTypeSet(subject) to 'subject'.
if (inputs_.length() == 0)
return nullptr;
MDefinition* subject = getOperand(0);
if (subject->isFilterTypeSet())
subject = subject->toFilterTypeSet()->input();
// Not same type, don't fold.
if (subject->type() != type())
return nullptr;
// Phi is better typed (has typeset). Don't fold.
if (resultTypeSet() && !subject->resultTypeSet())
return nullptr;
// Phi is better typed (according to typeset). Don't fold.
if (subject->resultTypeSet() && resultTypeSet()) {
if (!subject->resultTypeSet()->isSubset(resultTypeSet()))
return nullptr;
}
for (size_t i = 1, e = numOperands(); i < e; i++) {
MDefinition* op = getOperand(i);
if (op == subject)
continue;
if (op->isFilterTypeSet() && op->toFilterTypeSet()->input() == subject)
continue;
return nullptr;
}
return subject;
}
MDefinition*
MPhi::foldsTo(TempAllocator& alloc)
{
if (MDefinition* def = operandIfRedundant())
return def;
if (MDefinition* def = foldsTernary())
return def;
if (MDefinition* def = foldsFilterTypeSet())
return def;
return this;
}
bool
MPhi::congruentTo(const MDefinition* ins) const
{
if (!ins->isPhi())
return false;
// Phis in different blocks may have different control conditions.
// For example, these phis:
//
// if (p)
// goto a
// a:
// t = phi(x, y)
//
// if (q)
// goto b
// b:
// s = phi(x, y)
//
// have identical operands, but they are not equvalent because t is
// effectively p?x:y and s is effectively q?x:y.
//
// For now, consider phis in different blocks incongruent.
if (ins->block() != block())
return false;
return congruentIfOperandsEqual(ins);
}
static inline TemporaryTypeSet*
MakeMIRTypeSet(MIRType type)
{
MOZ_ASSERT(type != MIRType_Value);
TypeSet::Type ntype = type == MIRType_Object
? TypeSet::AnyObjectType()
: TypeSet::PrimitiveType(ValueTypeFromMIRType(type));
LifoAlloc* alloc = GetJitContext()->temp->lifoAlloc();
return alloc->new_<TemporaryTypeSet>(alloc, ntype);
}
bool
jit::MergeTypes(MIRType* ptype, TemporaryTypeSet** ptypeSet,
MIRType newType, TemporaryTypeSet* newTypeSet)
{
if (newTypeSet && newTypeSet->empty())
return true;
if (newType != *ptype) {
if (IsNumberType(newType) && IsNumberType(*ptype)) {
*ptype = MIRType_Double;
} else if (*ptype != MIRType_Value) {
if (!*ptypeSet) {
*ptypeSet = MakeMIRTypeSet(*ptype);
if (!*ptypeSet)
return false;
}
*ptype = MIRType_Value;
} else if (*ptypeSet && (*ptypeSet)->empty()) {
*ptype = newType;
}
}
if (*ptypeSet) {
LifoAlloc* alloc = GetJitContext()->temp->lifoAlloc();
if (!newTypeSet && newType != MIRType_Value) {
newTypeSet = MakeMIRTypeSet(newType);
if (!newTypeSet)
return false;
}
if (newTypeSet) {
if (!newTypeSet->isSubset(*ptypeSet)) {
*ptypeSet = TypeSet::unionSets(*ptypeSet, newTypeSet, alloc);
if (!*ptypeSet)
return false;
}
} else {
*ptypeSet = nullptr;
}
}
return true;
}
// Tests whether 'types' includes all possible values represented by
// input/inputTypes.
bool
jit::TypeSetIncludes(TypeSet* types, MIRType input, TypeSet* inputTypes)
{
if (!types)
return inputTypes && inputTypes->empty();
switch (input) {
case MIRType_Undefined:
case MIRType_Null:
case MIRType_Boolean:
case MIRType_Int32:
case MIRType_Double:
case MIRType_Float32:
case MIRType_String:
case MIRType_Symbol:
case MIRType_MagicOptimizedArguments:
return types->hasType(TypeSet::PrimitiveType(ValueTypeFromMIRType(input)));
case MIRType_Object:
return types->unknownObject() || (inputTypes && inputTypes->isSubset(types));
case MIRType_Value:
return types->unknown() || (inputTypes && inputTypes->isSubset(types));
default:
MOZ_CRASH("Bad input type");
}
}
// Tests if two type combos (type/typeset) are equal.
bool
jit::EqualTypes(MIRType type1, TemporaryTypeSet* typeset1,
MIRType type2, TemporaryTypeSet* typeset2)
{
// Types should equal.
if (type1 != type2)
return false;
// Both have equal type and no typeset.
if (!typeset1 && !typeset2)
return true;
// If only one instructions has a typeset.
// Test if the typset contains the same information as the MIRType.
if (typeset1 && !typeset2)
return TypeSetIncludes(typeset1, type2, nullptr);
if (!typeset1 && typeset2)
return TypeSetIncludes(typeset2, type1, nullptr);
// Typesets should equal.
return typeset1->equals(typeset2);
}
// Tests whether input/inputTypes can always be stored to an unboxed
// object/array property with the given unboxed type.
bool
jit::CanStoreUnboxedType(TempAllocator& alloc,
JSValueType unboxedType, MIRType input, TypeSet* inputTypes)
{
TemporaryTypeSet types;
switch (unboxedType) {
case JSVAL_TYPE_BOOLEAN:
case JSVAL_TYPE_INT32:
case JSVAL_TYPE_DOUBLE:
case JSVAL_TYPE_STRING:
types.addType(TypeSet::PrimitiveType(unboxedType), alloc.lifoAlloc());
break;
case JSVAL_TYPE_OBJECT:
types.addType(TypeSet::AnyObjectType(), alloc.lifoAlloc());
types.addType(TypeSet::NullType(), alloc.lifoAlloc());
break;
default:
MOZ_CRASH("Bad unboxed type");
}
return TypeSetIncludes(&types, input, inputTypes);
}
static bool
CanStoreUnboxedType(TempAllocator& alloc, JSValueType unboxedType, MDefinition* value)
{
return CanStoreUnboxedType(alloc, unboxedType, value->type(), value->resultTypeSet());
}
bool
MPhi::specializeType()
{
#ifdef DEBUG
MOZ_ASSERT(!specialized_);
specialized_ = true;
#endif
MOZ_ASSERT(!inputs_.empty());
size_t start;
if (hasBackedgeType_) {
// The type of this phi has already been populated with potential types
// that could come in via loop backedges.
start = 0;
} else {
setResultType(getOperand(0)->type());
setResultTypeSet(getOperand(0)->resultTypeSet());
start = 1;
}
MIRType resultType = this->type();
TemporaryTypeSet* resultTypeSet = this->resultTypeSet();
for (size_t i = start; i < inputs_.length(); i++) {
MDefinition* def = getOperand(i);
if (!MergeTypes(&resultType, &resultTypeSet, def->type(), def->resultTypeSet()))
return false;
}
setResultType(resultType);
setResultTypeSet(resultTypeSet);
return true;
}
bool
MPhi::addBackedgeType(MIRType type, TemporaryTypeSet* typeSet)
{
MOZ_ASSERT(!specialized_);
if (hasBackedgeType_) {
MIRType resultType = this->type();
TemporaryTypeSet* resultTypeSet = this->resultTypeSet();
if (!MergeTypes(&resultType, &resultTypeSet, type, typeSet))
return false;
setResultType(resultType);
setResultTypeSet(resultTypeSet);
} else {
setResultType(type);
setResultTypeSet(typeSet);
hasBackedgeType_ = true;
}
return true;
}
bool
MPhi::typeIncludes(MDefinition* def)
{
if (def->type() == MIRType_Int32 && this->type() == MIRType_Double)
return true;
if (TemporaryTypeSet* types = def->resultTypeSet()) {
if (this->resultTypeSet())
return types->isSubset(this->resultTypeSet());
if (this->type() == MIRType_Value || types->empty())
return true;
return this->type() == types->getKnownMIRType();
}
if (def->type() == MIRType_Value) {
// This phi must be able to be any value.
return this->type() == MIRType_Value
&& (!this->resultTypeSet() || this->resultTypeSet()->unknown());
}
return this->mightBeType(def->type());
}
bool
MPhi::checkForTypeChange(MDefinition* ins, bool* ptypeChange)
{
MIRType resultType = this->type();
TemporaryTypeSet* resultTypeSet = this->resultTypeSet();
if (!MergeTypes(&resultType, &resultTypeSet, ins->type(), ins->resultTypeSet()))
return false;
if (resultType != this->type() || resultTypeSet != this->resultTypeSet()) {
*ptypeChange = true;
setResultType(resultType);
setResultTypeSet(resultTypeSet);
}
return true;
}
void
MCall::addArg(size_t argnum, MDefinition* arg)
{
// The operand vector is initialized in reverse order by the IonBuilder.
// It cannot be checked for consistency until all arguments are added.
// FixedList doesn't initialize its elements, so do an unchecked init.
initOperand(argnum + NumNonArgumentOperands, arg);
}
static inline bool
IsConstant(MDefinition* def, double v)
{
if (!def->isConstant())
return false;
return NumbersAreIdentical(def->toConstant()->value().toNumber(), v);
}
MDefinition*
MBinaryBitwiseInstruction::foldsTo(TempAllocator& alloc)
{
if (specialization_ != MIRType_Int32)
return this;
if (MDefinition* folded = EvaluateConstantOperands(alloc, this))
return folded;
return this;
}
MDefinition*
MBinaryBitwiseInstruction::foldUnnecessaryBitop()
{
if (specialization_ != MIRType_Int32)
return this;
// Eliminate bitwise operations that are no-ops when used on integer
// inputs, such as (x | 0).
MDefinition* lhs = getOperand(0);
MDefinition* rhs = getOperand(1);
if (IsConstant(lhs, 0))
return foldIfZero(0);
if (IsConstant(rhs, 0))
return foldIfZero(1);
if (IsConstant(lhs, -1))
return foldIfNegOne(0);
if (IsConstant(rhs, -1))
return foldIfNegOne(1);
if (lhs == rhs)
return foldIfEqual();
return this;
}
void
MBinaryBitwiseInstruction::infer(BaselineInspector*, jsbytecode*)
{
if (getOperand(0)->mightBeType(MIRType_Object) || getOperand(0)->mightBeType(MIRType_Symbol) ||
getOperand(1)->mightBeType(MIRType_Object) || getOperand(1)->mightBeType(MIRType_Symbol))
{
specialization_ = MIRType_None;
} else {
specializeAsInt32();
}
}
void
MBinaryBitwiseInstruction::specializeAsInt32()
{
specialization_ = MIRType_Int32;
MOZ_ASSERT(type() == MIRType_Int32);
if (isBitOr() || isBitAnd() || isBitXor())
setCommutative();
}
void
MShiftInstruction::infer(BaselineInspector*, jsbytecode*)
{
if (getOperand(0)->mightBeType(MIRType_Object) || getOperand(1)->mightBeType(MIRType_Object) ||
getOperand(0)->mightBeType(MIRType_Symbol) || getOperand(1)->mightBeType(MIRType_Symbol))
specialization_ = MIRType_None;
else
specialization_ = MIRType_Int32;
}
void
MUrsh::infer(BaselineInspector* inspector, jsbytecode* pc)
{
if (getOperand(0)->mightBeType(MIRType_Object) || getOperand(1)->mightBeType(MIRType_Object) ||
getOperand(0)->mightBeType(MIRType_Symbol) || getOperand(1)->mightBeType(MIRType_Symbol))
{
specialization_ = MIRType_None;
setResultType(MIRType_Value);
return;
}
if (inspector->hasSeenDoubleResult(pc)) {
specialization_ = MIRType_Double;
setResultType(MIRType_Double);
return;
}
specialization_ = MIRType_Int32;
setResultType(MIRType_Int32);
}
static inline bool
CanProduceNegativeZero(MDefinition* def) {
// Test if this instruction can produce negative zero even when bailing out
// and changing types.
switch (def->op()) {
case MDefinition::Op_Constant:
if (def->type() == MIRType_Double && def->constantValue().toDouble() == -0.0)
return true;
case MDefinition::Op_BitAnd:
case MDefinition::Op_BitOr:
case MDefinition::Op_BitXor:
case MDefinition::Op_BitNot:
case MDefinition::Op_Lsh:
case MDefinition::Op_Rsh:
return false;
default:
return true;
}
}
static inline bool
NeedNegativeZeroCheck(MDefinition* def)
{
// Test if all uses have the same semantics for -0 and 0
for (MUseIterator use = def->usesBegin(); use != def->usesEnd(); use++) {
if (use->consumer()->isResumePoint())
continue;
MDefinition* use_def = use->consumer()->toDefinition();
switch (use_def->op()) {
case MDefinition::Op_Add: {
// If add is truncating -0 and 0 are observed as the same.
if (use_def->toAdd()->isTruncated())
break;
// x + y gives -0, when both x and y are -0
// Figure out the order in which the addition's operands will
// execute. EdgeCaseAnalysis::analyzeLate has renumbered the MIR
// definitions for us so that this just requires comparing ids.
MDefinition* first = use_def->toAdd()->lhs();
MDefinition* second = use_def->toAdd()->rhs();
if (first->id() > second->id()) {
MDefinition* temp = first;
first = second;
second = temp;
}
// Negative zero checks can be removed on the first executed
// operand only if it is guaranteed the second executed operand
// will produce a value other than -0. While the second is
// typed as an int32, a bailout taken between execution of the
// operands may change that type and cause a -0 to flow to the
// second.
//
// There is no way to test whether there are any bailouts
// between execution of the operands, so remove negative
// zero checks from the first only if the second's type is
// independent from type changes that may occur after bailing.
if (def == first && CanProduceNegativeZero(second))
return true;
// The negative zero check can always be removed on the second
// executed operand; by the time this executes the first will have
// been evaluated as int32 and the addition's result cannot be -0.
break;
}
case MDefinition::Op_Sub: {
// If sub is truncating -0 and 0 are observed as the same
if (use_def->toSub()->isTruncated())
break;
// x + y gives -0, when x is -0 and y is 0
// We can remove the negative zero check on the rhs, only if we
// are sure the lhs isn't negative zero.
// The lhs is typed as integer (i.e. not -0.0), but it can bailout
// and change type. This should be fine if the lhs is executed
// first. However if the rhs is executed first, the lhs can bail,
// change type and become -0.0 while the rhs has already been
// optimized to not make a difference between zero and negative zero.
MDefinition* lhs = use_def->toSub()->lhs();
MDefinition* rhs = use_def->toSub()->rhs();
if (rhs->id() < lhs->id() && CanProduceNegativeZero(lhs))
return true;
/* Fall through... */
}
case MDefinition::Op_StoreElement:
case MDefinition::Op_StoreElementHole:
case MDefinition::Op_LoadElement:
case MDefinition::Op_LoadElementHole:
case MDefinition::Op_LoadUnboxedScalar:
case MDefinition::Op_LoadTypedArrayElementHole:
case MDefinition::Op_CharCodeAt:
case MDefinition::Op_Mod:
// Only allowed to remove check when definition is the second operand
if (use_def->getOperand(0) == def)
return true;
for (size_t i = 2, e = use_def->numOperands(); i < e; i++) {
if (use_def->getOperand(i) == def)
return true;
}
break;
case MDefinition::Op_BoundsCheck:
// Only allowed to remove check when definition is the first operand
if (use_def->toBoundsCheck()->getOperand(1) == def)
return true;
break;
case MDefinition::Op_ToString:
case MDefinition::Op_FromCharCode:
case MDefinition::Op_TableSwitch:
case MDefinition::Op_Compare:
case MDefinition::Op_BitAnd:
case MDefinition::Op_BitOr:
case MDefinition::Op_BitXor:
case MDefinition::Op_Abs:
case MDefinition::Op_TruncateToInt32:
// Always allowed to remove check. No matter which operand.
break;
default:
return true;
}
}
return false;
}
MBinaryArithInstruction*
MBinaryArithInstruction::New(TempAllocator& alloc, Opcode op,
MDefinition* left, MDefinition* right)
{
switch (op) {
case Op_Add:
return MAdd::New(alloc, left, right);
case Op_Sub:
return MSub::New(alloc, left, right);
case Op_Mul:
return MMul::New(alloc, left, right);
case Op_Div:
return MDiv::New(alloc, left, right);
case Op_Mod:
return MMod::New(alloc, left, right);
default:
MOZ_CRASH("unexpected binary opcode");
}
}
void
MBinaryArithInstruction::setNumberSpecialization(TempAllocator& alloc, BaselineInspector* inspector,
jsbytecode* pc)
{
setSpecialization(MIRType_Double);
// Try to specialize as int32.
if (getOperand(0)->type() == MIRType_Int32 && getOperand(1)->type() == MIRType_Int32) {
bool seenDouble = inspector->hasSeenDoubleResult(pc);
// Use int32 specialization if the operation doesn't overflow on its
// constant operands and if the operation has never overflowed.
if (!seenDouble && !constantDoubleResult(alloc))
setInt32Specialization();
}
}
bool
MBinaryArithInstruction::constantDoubleResult(TempAllocator& alloc)
{
bool typeChange = false;
EvaluateConstantOperands(alloc, this, &typeChange);
return typeChange;
}
MDefinition*
MBinaryArithInstruction::foldsTo(TempAllocator& alloc)
{
if (specialization_ == MIRType_None)
return this;
MDefinition* lhs = getOperand(0);
MDefinition* rhs = getOperand(1);
if (MConstant* folded = EvaluateConstantOperands(alloc, this)) {
if (isTruncated()) {
if (!folded->block())
block()->insertBefore(this, folded);
return MTruncateToInt32::New(alloc, folded);
}
return folded;
}
// 0 + -0 = 0. So we can't remove addition
if (isAdd() && specialization_ != MIRType_Int32)
return this;
if (IsConstant(rhs, getIdentity())) {
if (isTruncated())
return MTruncateToInt32::New(alloc, lhs);
return lhs;
}
// subtraction isn't commutative. So we can't remove subtraction when lhs equals 0
if (isSub())
return this;
if (IsConstant(lhs, getIdentity())) {
if (isTruncated())
return MTruncateToInt32::New(alloc, rhs);
return rhs; // x op id => x
}
return this;
}
void
MFilterTypeSet::trySpecializeFloat32(TempAllocator& alloc)
{
MDefinition* in = input();
if (in->type() != MIRType_Float32)
return;
setResultType(MIRType_Float32);
}
bool
MFilterTypeSet::canProduceFloat32() const
{
// A FilterTypeSet should be a producer if the input is a producer too.
// Also, be overly conservative by marking as not float32 producer when the
// input is a phi, as phis can be cyclic (phiA -> FilterTypeSet -> phiB ->
// phiA) and FilterTypeSet doesn't belong in the Float32 phi analysis.
return !input()->isPhi() && input()->canProduceFloat32();
}
bool
MFilterTypeSet::canConsumeFloat32(MUse* operand) const
{
MOZ_ASSERT(getUseFor(0) == operand);
// A FilterTypeSet should be a consumer if all uses are consumer. See also
// comment below MFilterTypeSet::canProduceFloat32.
bool allConsumerUses = true;
for (MUseDefIterator use(this); allConsumerUses && use; use++)
allConsumerUses &= !use.def()->isPhi() && use.def()->canConsumeFloat32(use.use());
return allConsumerUses;
}
void
MBinaryArithInstruction::trySpecializeFloat32(TempAllocator& alloc)
{
// Do not use Float32 if we can use int32.
if (specialization_ == MIRType_Int32)
return;
if (specialization_ == MIRType_None)
return;
MDefinition* left = lhs();
MDefinition* right = rhs();
if (!left->canProduceFloat32() || !right->canProduceFloat32() ||
!CheckUsesAreFloat32Consumers(this))
{
if (left->type() == MIRType_Float32)
ConvertDefinitionToDouble<0>(alloc, left, this);
if (right->type() == MIRType_Float32)
ConvertDefinitionToDouble<1>(alloc, right, this);
return;
}
specialization_ = MIRType_Float32;
setResultType(MIRType_Float32);
}
void
MMinMax::trySpecializeFloat32(TempAllocator& alloc)
{
if (specialization_ == MIRType_Int32)
return;
MDefinition* left = lhs();
MDefinition* right = rhs();
if (!(left->canProduceFloat32() || (left->isMinMax() && left->type() == MIRType_Float32)) ||
!(right->canProduceFloat32() || (right->isMinMax() && right->type() == MIRType_Float32)))
{
if (left->type() == MIRType_Float32)
ConvertDefinitionToDouble<0>(alloc, left, this);
if (right->type() == MIRType_Float32)
ConvertDefinitionToDouble<1>(alloc, right, this);
return;
}
specialization_ = MIRType_Float32;
setResultType(MIRType_Float32);
}
MDefinition*
MMinMax::foldsTo(TempAllocator& alloc)
{
if (!lhs()->isConstant() && !rhs()->isConstant())
return this;
// Directly apply math utility to compare the rhs() and lhs() when
// they are both constants.
if (lhs()->isConstant() && rhs()->isConstant()) {
Value lval = lhs()->toConstant()->value();
Value rval = rhs()->toConstant()->value();
if (!lval.isNumber() || !rval.isNumber())
return this;
double lnum = lval.toNumber();
double rnum = rval.toNumber();
double result;
if (isMax())
result = js::math_max_impl(lnum, rnum);
else
result = js::math_min_impl(lnum, rnum);
// The folded MConstant should maintain the same MIRType with
// the original MMinMax.
if (type() == MIRType_Int32) {
int32_t cast;
if (mozilla::NumberEqualsInt32(result, &cast))
return MConstant::New(alloc, Int32Value(cast));
} else {
MOZ_ASSERT(IsFloatingPointType(type()));
MConstant* constant = MConstant::New(alloc, DoubleValue(result));
if (type() == MIRType_Float32)
constant->setResultType(MIRType_Float32);
return constant;
}
}
MDefinition* operand = lhs()->isConstantValue() ? rhs() : lhs();
const js::Value& val = lhs()->isConstantValue() ? lhs()->constantValue() : rhs()->constantValue();
if (operand->isToDouble() && operand->getOperand(0)->type() == MIRType_Int32) {
// min(int32, cte >= INT32_MAX) = int32
if (val.isDouble() && val.toDouble() >= INT32_MAX && !isMax()) {
MLimitedTruncate* limit =
MLimitedTruncate::New(alloc, operand->getOperand(0), MDefinition::NoTruncate);
block()->insertBefore(this, limit);
MToDouble* toDouble = MToDouble::New(alloc, limit);
return toDouble;
}
// max(int32, cte <= INT32_MIN) = int32
if (val.isDouble() && val.toDouble() <= INT32_MIN && isMax()) {
MLimitedTruncate* limit =
MLimitedTruncate::New(alloc, operand->getOperand(0), MDefinition::NoTruncate);
block()->insertBefore(this, limit);
MToDouble* toDouble = MToDouble::New(alloc, limit);
return toDouble;
}
}
return this;
}
bool
MAbs::fallible() const
{
return !implicitTruncate_ && (!range() || !range()->hasInt32Bounds());
}
void
MAbs::trySpecializeFloat32(TempAllocator& alloc)
{
// Do not use Float32 if we can use int32.
if (input()->type() == MIRType_Int32)
return;
if (!input()->canProduceFloat32() || !CheckUsesAreFloat32Consumers(this)) {
if (input()->type() == MIRType_Float32)
ConvertDefinitionToDouble<0>(alloc, input(), this);
return;
}
setResultType(MIRType_Float32);
specialization_ = MIRType_Float32;
}
MDefinition*
MDiv::foldsTo(TempAllocator& alloc)
{
if (specialization_ == MIRType_None)
return this;
if (MDefinition* folded = EvaluateConstantOperands(alloc, this))
return folded;
if (MDefinition* folded = EvaluateExactReciprocal(alloc, this))
return folded;
return this;
}
void
MDiv::analyzeEdgeCasesForward()
{
// This is only meaningful when doing integer division.
if (specialization_ != MIRType_Int32)
return;
// Try removing divide by zero check
if (rhs()->isConstantValue() && !rhs()->constantValue().isInt32(0))
canBeDivideByZero_ = false;
// If lhs is a constant int != INT32_MIN, then
// negative overflow check can be skipped.
if (lhs()->isConstantValue() && !lhs()->constantValue().isInt32(INT32_MIN))
canBeNegativeOverflow_ = false;
// If rhs is a constant int != -1, likewise.
if (rhs()->isConstantValue() && !rhs()->constantValue().isInt32(-1))
canBeNegativeOverflow_ = false;
// If lhs is != 0, then negative zero check can be skipped.
if (lhs()->isConstantValue() && !lhs()->constantValue().isInt32(0))
setCanBeNegativeZero(false);
// If rhs is >= 0, likewise.
if (rhs()->isConstantValue()) {
const js::Value& val = rhs()->constantValue();
if (val.isInt32() && val.toInt32() >= 0)
setCanBeNegativeZero(false);
}
}
void
MDiv::analyzeEdgeCasesBackward()
{
if (canBeNegativeZero() && !NeedNegativeZeroCheck(this))
setCanBeNegativeZero(false);
}
bool
MDiv::fallible() const
{
return !isTruncated();
}
MDefinition*
MMod::foldsTo(TempAllocator& alloc)
{
if (specialization_ == MIRType_None)
return this;
if (MDefinition* folded = EvaluateConstantOperands(alloc, this))
return folded;
return this;
}
void
MMod::analyzeEdgeCasesForward()
{
// These optimizations make sense only for integer division
if (specialization_ != MIRType_Int32)
return;
if (rhs()->isConstantValue() && !rhs()->constantValue().isInt32(0))
canBeDivideByZero_ = false;
if (rhs()->isConstantValue()) {
int32_t n = rhs()->constantValue().toInt32();
if (n > 0 && !IsPowerOfTwo(n))
canBePowerOfTwoDivisor_ = false;
}