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Make it possible to assert that certain instance types are compatible wrt HAllocate.

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Turns clear_next_map_word_ into a flag and adds a new method
CompatibleInstanceTypes(). This is used in BuildUncheckedStringAdd()
to ASSERT that there's no difference wrt. HAllocate in using
CONS_STRING_TYPE vs CONS_ASCII_STRING_TYPE.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/110443003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18428 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
bmeurer@chromium.org 2014-01-02 06:26:44 +00:00
parent c82a2e648b
commit a53dcc9da1
3 changed files with 48 additions and 23 deletions
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4
src/hydrogen-instructions.cc
View File

@ -3492,7 +3492,7 @@ void HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
dominator_allocate->ClearNextMapWord(original_object_size);
#endif
dominator_allocate->clear_next_map_word_ = clear_next_map_word_;
dominator_allocate->UpdateClearNextMapWord(MustClearNextMapWord());
// After that replace the dominated allocate instruction.
HInstruction* inner_offset = HConstant::CreateAndInsertBefore(
@ -3635,7 +3635,7 @@ void HAllocate::CreateFreeSpaceFiller(int32_t free_space_size) {
void HAllocate::ClearNextMapWord(int offset) {
if (clear_next_map_word_) {
if (MustClearNextMapWord()) {
Zone* zone = block()->zone();
HObjectAccess access = HObjectAccess::ForJSObjectOffset(offset);
HStoreNamedField* clear_next_map =

65
src/hydrogen-instructions.h
View File

@ -5438,6 +5438,12 @@ class HLoadGlobalGeneric V8_FINAL : public HTemplateInstruction<2> {
class HAllocate V8_FINAL : public HTemplateInstruction<2> {
public:
static bool CompatibleInstanceTypes(InstanceType type1,
InstanceType type2) {
return ComputeFlags(TENURED, type1) == ComputeFlags(TENURED, type2) &&
ComputeFlags(NOT_TENURED, type1) == ComputeFlags(NOT_TENURED, type2);
}
static HAllocate* New(Zone* zone,
HValue* context,
HValue* size,
@ -5496,6 +5502,10 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
flags_ = static_cast<HAllocate::Flags>(flags_ | PREFILL_WITH_FILLER);
}
bool MustClearNextMapWord() const {
return (flags_ & CLEAR_NEXT_MAP_WORD) != 0;
}
void MakeDoubleAligned() {
flags_ = static_cast<HAllocate::Flags>(flags_ | ALLOCATE_DOUBLE_ALIGNED);
}
@ -5513,7 +5523,8 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
ALLOCATE_IN_OLD_DATA_SPACE = 1 << 1,
ALLOCATE_IN_OLD_POINTER_SPACE = 1 << 2,
ALLOCATE_DOUBLE_ALIGNED = 1 << 3,
PREFILL_WITH_FILLER = 1 << 4
PREFILL_WITH_FILLER = 1 << 4,
CLEAR_NEXT_MAP_WORD = 1 << 5
};
HAllocate(HValue* context,
@ -5524,32 +5535,15 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
Handle<AllocationSite> allocation_site =
Handle<AllocationSite>::null())
: HTemplateInstruction<2>(type),
flags_(ComputeFlags(pretenure_flag, instance_type)),
dominating_allocate_(NULL),
filler_free_space_size_(NULL),
clear_next_map_word_(false) {
filler_free_space_size_(NULL) {
SetOperandAt(0, context);
SetOperandAt(1, size);
set_representation(Representation::Tagged());
SetFlag(kTrackSideEffectDominators);
SetGVNFlag(kChangesNewSpacePromotion);
SetGVNFlag(kDependsOnNewSpacePromotion);
flags_ = pretenure_flag == TENURED
? (Heap::TargetSpaceId(instance_type) == OLD_POINTER_SPACE
? ALLOCATE_IN_OLD_POINTER_SPACE : ALLOCATE_IN_OLD_DATA_SPACE)
: ALLOCATE_IN_NEW_SPACE;
if (instance_type == FIXED_DOUBLE_ARRAY_TYPE) {
flags_ = static_cast<HAllocate::Flags>(flags_ | ALLOCATE_DOUBLE_ALIGNED);
}
// We have to fill the allocated object with one word fillers if we do
// not use allocation folding since some allocations may depend on each
// other, i.e., have a pointer to each other. A GC in between these
// allocations may leave such objects behind in a not completely initialized
// state.
if (!FLAG_use_gvn || !FLAG_use_allocation_folding) {
flags_ = static_cast<HAllocate::Flags>(flags_ | PREFILL_WITH_FILLER);
}
clear_next_map_word_ = pretenure_flag == NOT_TENURED &&
AllocationSite::CanTrack(instance_type);
if (FLAG_trace_pretenuring) {
PrintF("HAllocate with AllocationSite %p %s\n",
@ -5560,6 +5554,36 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
}
}
static Flags ComputeFlags(PretenureFlag pretenure_flag,
InstanceType instance_type) {
Flags flags = pretenure_flag == TENURED
? (Heap::TargetSpaceId(instance_type) == OLD_POINTER_SPACE
? ALLOCATE_IN_OLD_POINTER_SPACE : ALLOCATE_IN_OLD_DATA_SPACE)
: ALLOCATE_IN_NEW_SPACE;
if (instance_type == FIXED_DOUBLE_ARRAY_TYPE) {
flags = static_cast<Flags>(flags | ALLOCATE_DOUBLE_ALIGNED);
}
// We have to fill the allocated object with one word fillers if we do
// not use allocation folding since some allocations may depend on each
// other, i.e., have a pointer to each other. A GC in between these
// allocations may leave such objects behind in a not completely initialized
// state.
if (!FLAG_use_gvn || !FLAG_use_allocation_folding) {
flags = static_cast<Flags>(flags | PREFILL_WITH_FILLER);
}
if (pretenure_flag == NOT_TENURED &&
AllocationSite::CanTrack(instance_type)) {
flags = static_cast<Flags>(flags | CLEAR_NEXT_MAP_WORD);
}
return flags;
}
void UpdateClearNextMapWord(bool clear_next_map_word) {
flags_ = static_cast<Flags>(clear_next_map_word
? flags_ | CLEAR_NEXT_MAP_WORD
: flags_ & ~CLEAR_NEXT_MAP_WORD);
}
void UpdateSize(HValue* size) {
SetOperandAt(1, size);
}
@ -5583,7 +5607,6 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
Handle<Map> known_initial_map_;
HAllocate* dominating_allocate_;
HStoreNamedField* filler_free_space_size_;
bool clear_next_map_word_;
};

2
src/hydrogen.cc
View File

@ -1779,6 +1779,8 @@ HValue* HGraphBuilder::BuildUncheckedStringAdd(HValue* left,
// pass CONS_STRING_TYPE or CONS_ASCII_STRING_TYPE here, so we just use
// CONS_STRING_TYPE here. Below we decide whether the cons string is
// one-byte or two-byte and set the appropriate map.
ASSERT(HAllocate::CompatibleInstanceTypes(CONS_STRING_TYPE,
CONS_ASCII_STRING_TYPE));
HAllocate* string = Add<HAllocate>(Add<HConstant>(ConsString::kSize),
HType::String(), pretenure_flag,
CONS_STRING_TYPE);