bool
TypeBarrierPolicy::adjustInputs(TempAllocator &alloc, MInstruction *def)
{
MTypeBarrier *ins = def->toTypeBarrier();
MIRType inputType = ins->getOperand(0)->type();
MIRType outputType = ins->type();
// Input and output type are already in accordance.
if (inputType == outputType)
return true;
// Output is a value, currently box the input.
if (outputType == MIRType_Value) {
// XXX: Possible optimization: decrease resultTypeSet to only include
// the inputType. This will remove the need for boxing.
MOZ_ASSERT(inputType != MIRType_Value);
ins->replaceOperand(0, boxAt(alloc, ins, ins->getOperand(0)));
return true;
}
// Box input if needed.
if (inputType != MIRType_Value) {
MOZ_ASSERT(ins->alwaysBails());
ins->replaceOperand(0, boxAt(alloc, ins, ins->getOperand(0)));
}
// We can't unbox a value to null/undefined/lazyargs. So keep output
// also a value.
// Note: Using setResultType shouldn't be done in TypePolicies,
// Here it is fine, since the type barrier has no uses.
if (IsNullOrUndefined(outputType) || outputType == MIRType_MagicOptimizedArguments) {
MOZ_ASSERT(!ins->hasDefUses());
ins->setResultType(MIRType_Value);
return true;
}
// Unbox / propagate the right type.
MUnbox::Mode mode = MUnbox::TypeBarrier;
MInstruction *replace = MUnbox::New(alloc, ins->getOperand(0), ins->type(), mode);
ins->block()->insertBefore(ins, replace);
ins->replaceOperand(0, replace);
if (!replace->typePolicy()->adjustInputs(alloc, replace))
return false;
// The TypeBarrier is equivalent to removing branches with unexpected
// types. The unexpected types would have changed Range Analysis
// predictions. As such, we need to prevent destructive optimizations.
ins->block()->flagOperandsOfPrunedBranches(replace);
return true;
}
bool
TypeBarrierPolicy::adjustInputs(MInstruction *def)
{
MTypeBarrier *ins = def->toTypeBarrier();
MIRType inputType = ins->getOperand(0)->type();
MIRType outputType = ins->type();
// Input and output type are already in accordance.
if (inputType == outputType)
return true;
// Output is a value, currently box the input.
if (outputType == MIRType_Value) {
// XXX: Possible optimization: decrease resultTypeSet to only include
// the inputType. This will remove the need for boxing.
JS_ASSERT(inputType != MIRType_Value);
ins->replaceOperand(0, boxAt(ins, ins->getOperand(0)));
return true;
}
// Input is a value. Unbox the input to the requested type.
if (inputType == MIRType_Value) {
JS_ASSERT(outputType != MIRType_Value);
// We can't unbox a value to null/undefined. So keep output also a value.
if (IsNullOrUndefined(outputType) || outputType == MIRType_Magic) {
ins->setResultType(MIRType_Value);
return true;
}
MUnbox *unbox = MUnbox::New(ins->getOperand(0), outputType,
MUnbox::TypeBarrier, ins->bailoutKind());
ins->block()->insertBefore(ins, unbox);
ins->replaceOperand(0, unbox);
return true;
}
// In the remaining cases we will alway bail. OutputType doesn't matter.
// Take inputType so we can use redefine during lowering.
JS_ASSERT(ins->alwaysBails());
ins->setResultType(inputType);
return true;
}