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Bug 1059187 - Set Undefined/Null in else branch of filtering. r=h4writer.

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This commit is contained in:
Sushant Dinesh 2014-10-14 02:19:00 +02:00
parent 79eb0d5c68
commit bcd31ebf4e
1 changed files with 46 additions and 24 deletions
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70
js/src/jit/IonBuilder.cpp
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@ -3276,42 +3276,64 @@ IonBuilder::improveTypesAtCompare(MCompare *ins, bool trueBranch, MTest *test)
return true;
}
MOZ_ASSERT(ins->jsop() == JSOP_STRICTNE || ins->jsop() == JSOP_NE ||
ins->jsop() == JSOP_STRICTEQ || ins->jsop() == JSOP_EQ);
// altersUndefined/Null represents if we can filter/set Undefined/Null.
bool altersUndefined, altersNull;
JSOp op = ins->jsop();
// JSOP_*NE only removes undefined/null from if/true branch
if (!trueBranch && (ins->jsop() == JSOP_STRICTNE || ins->jsop() == JSOP_NE))
return true;
// JSOP_*EQ only removes undefined/null from else/false branch
if (trueBranch && (ins->jsop() == JSOP_STRICTEQ || ins->jsop() == JSOP_EQ))
return true;
bool filtersUndefined = false;
bool filtersNull = false;
if (ins->jsop() == JSOP_STRICTEQ || ins->jsop() == JSOP_STRICTNE) {
filtersUndefined = (ins->compareType() == MCompare::Compare_Undefined);
filtersNull = (ins->compareType() == MCompare::Compare_Null);
} else {
filtersUndefined = filtersNull = true;
switch(op) {
case JSOP_STRICTNE:
case JSOP_STRICTEQ:
altersUndefined = ins->compareType() == MCompare::Compare_Undefined;
altersNull = ins->compareType() == MCompare::Compare_Null;
break;
case JSOP_NE:
case JSOP_EQ:
altersUndefined = altersNull = true;
break;
default:
MOZ_CRASH("Relational compares not supported");
}
MDefinition *subject = ins->lhs();
MOZ_ASSERT(IsNullOrUndefined(ins->rhs()->type()));
MDefinition *subject = ins->lhs();
if (!subject->resultTypeSet() || subject->resultTypeSet()->unknown())
return true;
// Make sure the type is present we want to filter else this is a NOP.
if ((!filtersUndefined || !subject->mightBeType(MIRType_Undefined)) &&
(!filtersNull || !subject->mightBeType(MIRType_Null)))
if (!subject->mightBeType(MIRType_Undefined) &&
!subject->mightBeType(MIRType_Null))
{
return true;
}
types::TemporaryTypeSet *type =
subject->resultTypeSet()->filter(alloc_->lifoAlloc(), filtersUndefined,
filtersNull);
if (!altersUndefined && !altersNull)
return true;
types::TemporaryTypeSet *type;
// Decide if we need to filter the type or set it.
if ((op == JSOP_STRICTEQ || op == JSOP_EQ) ^ trueBranch) {
// Filter undefined/null
type = subject->resultTypeSet()->filter(alloc_->lifoAlloc(), altersUndefined,
altersNull);
} else {
// Set undefined/null.
uint32_t flags = 0;
if (altersUndefined) {
flags |= types::TYPE_FLAG_UNDEFINED;
// If TypeSet emulates undefined, then we cannot filter the objects.
if (subject->resultTypeSet()->maybeEmulatesUndefined())
flags |= types::TYPE_FLAG_ANYOBJECT;
}
if (altersNull)
flags |= types::TYPE_FLAG_NULL;
types::TemporaryTypeSet base(flags, static_cast<types::TypeObjectKey**>(nullptr));
type = types::TypeSet::intersectSets(&base, subject->resultTypeSet(), alloc_->lifoAlloc());
}
if (!type)
return false;