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Folding of bounded dynamic size allocations with const size allocations.

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R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/301973014

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21675 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
ishell@chromium.org 2014-06-04 13:39:02 +00:00
parent 90a5b1414d
commit d0cd026821
2 changed files with 90 additions and 64 deletions
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148
src/hydrogen-instructions.cc
View File

@ -3757,25 +3757,13 @@ bool HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
}
HAllocate* dominator_allocate = HAllocate::cast(dominator);
HValue* dominator_size = dominator_allocate->size();
HValue* current_size = size();
// TODO(hpayer): Add support for non-constant allocation in dominator.
if (!dominator_size->IsInteger32Constant()) {
if (FLAG_trace_allocation_folding) {
PrintF("#%d (%s) cannot fold into #%d (%s), "
"dynamic allocation size in dominator\n",
id(), Mnemonic(), dominator->id(), dominator->Mnemonic());
}
return false;
}
dominator_allocate = GetFoldableDominator(dominator_allocate);
if (dominator_allocate == NULL) {
return false;
}
if (!has_size_upper_bound()) {
if (!has_size_upper_bound() || !dominator_allocate->has_size_upper_bound()) {
if (FLAG_trace_allocation_folding) {
PrintF("#%d (%s) cannot fold into #%d (%s), "
"can't estimate total allocation size\n",
@ -3784,6 +3772,19 @@ bool HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
return false;
}
HValue* dominator_size = dominator_allocate->size();
// TODO(ishell): support folding of dynamic size allocation with
// double aligned allocation.
if (!dominator_size->IsInteger32Constant() && MustAllocateDoubleAligned()) {
if (FLAG_trace_allocation_folding) {
PrintF("#%d (%s) cannot fold into #%d (%s), dynamic size "
"in dominator and double aligned requirement\n",
id(), Mnemonic(), dominator->id(), dominator->Mnemonic());
}
return false;
}
HValue* current_size = size();
if (!current_size->IsInteger32Constant()) {
// If it's not constant then it is a size_in_bytes calculation graph
// like this: (const_header_size + const_element_size * size).
@ -3808,61 +3809,82 @@ bool HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
(IsOldPointerSpaceAllocation() &&
dominator_allocate->IsOldPointerSpaceAllocation()));
// First update the size of the dominator allocate instruction.
dominator_size = dominator_allocate->size();
int32_t original_object_size =
HConstant::cast(dominator_size)->GetInteger32Constant();
int32_t dominator_size_constant = original_object_size;
// First update the size and size upper bound of the dominator allocate
// instruction.
int32_t dominator_size_upper_bound_value =
dominator_allocate->size_upper_bound()->GetInteger32Constant();
if (MustAllocateDoubleAligned()) {
if ((dominator_size_constant & kDoubleAlignmentMask) != 0) {
dominator_size_constant += kDoubleSize / 2;
if ((dominator_size_upper_bound_value & kDoubleAlignmentMask) != 0) {
dominator_size_upper_bound_value += kDoubleSize / 2;
}
}
int32_t current_size_max_value = size_upper_bound()->GetInteger32Constant();
int32_t new_dominator_size = dominator_size_constant + current_size_max_value;
int32_t new_dominator_size_upper_bound_value =
dominator_size_upper_bound_value +
size_upper_bound()->GetInteger32Constant();
// Since we clear the first word after folded memory, we cannot use the
// whole Page::kMaxRegularHeapObjectSize memory.
if (new_dominator_size > Page::kMaxRegularHeapObjectSize - kPointerSize) {
if (new_dominator_size_upper_bound_value >
Page::kMaxRegularHeapObjectSize - kPointerSize) {
if (FLAG_trace_allocation_folding) {
PrintF("#%d (%s) cannot fold into #%d (%s) due to size: %d\n",
id(), Mnemonic(), dominator_allocate->id(),
dominator_allocate->Mnemonic(), new_dominator_size);
dominator_allocate->Mnemonic(), new_dominator_size_upper_bound_value);
}
return false;
}
HInstruction* new_dominator_size_value;
if (current_size->IsInteger32Constant()) {
new_dominator_size_value =
HValue* aligned_dominator_size;
if (dominator_size->IsInteger32Constant()) {
aligned_dominator_size =
HConstant::CreateAndInsertBefore(zone,
context(),
new_dominator_size,
Representation::None(),
dominator_allocate);
} else {
HValue* new_dominator_size_constant =
HConstant::CreateAndInsertBefore(zone,
context(),
dominator_size_constant,
dominator_size_upper_bound_value,
Representation::Integer32(),
dominator_allocate);
// Add old and new size together and insert.
current_size->ChangeRepresentation(Representation::Integer32());
new_dominator_size_value = HAdd::New(zone, context(),
new_dominator_size_constant, current_size);
new_dominator_size_value->ClearFlag(HValue::kCanOverflow);
new_dominator_size_value->ChangeRepresentation(Representation::Integer32());
new_dominator_size_value->InsertBefore(dominator_allocate);
} else {
aligned_dominator_size = dominator_size;
}
dominator_allocate->UpdateSize(new_dominator_size_value);
HConstant* new_dominator_size_upper_bound =
HConstant::CreateAndInsertBefore(zone,
context(),
new_dominator_size_upper_bound_value,
Representation::None(),
dominator_allocate);
HInstruction* new_dominator_size;
if (current_size->IsInteger32Constant() &&
dominator_size->IsInteger32Constant()) {
new_dominator_size = new_dominator_size_upper_bound;
} else {
// Add old and new size together and insert.
if (current_size->IsInteger32Constant()) {
// Create a copy of constant and put it into the right place
current_size =
HConstant::CreateAndInsertBefore(zone,
context(),
current_size->GetInteger32Constant(),
Representation::Integer32(),
dominator_allocate);
} else {
current_size->ChangeRepresentation(Representation::Integer32());
}
new_dominator_size = HAdd::New(zone, context(),
aligned_dominator_size, current_size);
new_dominator_size->ClearFlag(HValue::kCanOverflow);
new_dominator_size->ChangeRepresentation(Representation::Integer32());
new_dominator_size->InsertBefore(dominator_allocate);
}
dominator_allocate->UpdateSize(new_dominator_size,
new_dominator_size_upper_bound);
if (MustAllocateDoubleAligned()) {
if (!dominator_allocate->MustAllocateDoubleAligned()) {
@ -3880,24 +3902,17 @@ bool HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
} else {
// TODO(hpayer): This is a short-term hack to make allocation mementos
// work again in new space.
dominator_allocate->ClearNextMapWord(original_object_size);
dominator_allocate->ClearNextMapWord(dominator_size);
}
dominator_allocate->UpdateClearNextMapWord(MustClearNextMapWord());
// After that replace the dominated allocate instruction.
HInstruction* inner_offset = HConstant::CreateAndInsertBefore(
zone,
context(),
dominator_size_constant,
Representation::None(),
this);
HInstruction* dominated_allocate_instr =
HInnerAllocatedObject::New(zone,
context(),
dominator_allocate,
inner_offset,
aligned_dominator_size,
type());
dominated_allocate_instr->InsertBefore(this);
DeleteAndReplaceWith(dominated_allocate_instr);
@ -4024,14 +4039,25 @@ void HAllocate::CreateFreeSpaceFiller(int32_t free_space_size) {
}
void HAllocate::ClearNextMapWord(int offset) {
void HAllocate::ClearNextMapWord(HValue* offset) {
if (MustClearNextMapWord()) {
Zone* zone = block()->zone();
HObjectAccess access =
HObjectAccess::ForObservableJSObjectOffset(offset);
HStoreNamedField* clear_next_map =
HStoreNamedField::New(zone, context(), this, access,
block()->graph()->GetConstant0());
HInstruction* clear_next_map;
if (offset->IsInteger32Constant()) {
int offset_value = HConstant::cast(offset)->GetInteger32Constant();
HObjectAccess access =
HObjectAccess::ForObservableJSObjectOffset(offset_value);
clear_next_map =
HStoreNamedField::New(zone, context(), this, access,
block()->graph()->GetConstant0());
} else {
clear_next_map =
HStoreKeyed::New(zone, context(),
this, offset,
block()->graph()->GetConstant0(),
FAST_HOLEY_SMI_ELEMENTS);
}
clear_next_map->ClearAllSideEffects();
clear_next_map->InsertAfter(this);
}

6
src/hydrogen-instructions.h
View File

@ -5589,12 +5589,12 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
: flags_ & ~CLEAR_NEXT_MAP_WORD);
}
void UpdateSize(HValue* size) {
void UpdateSize(HValue* size, HConstant* size_upper_bound = NULL) {
SetOperandAt(1, size);
if (size->IsInteger32Constant()) {
size_upper_bound_ = HConstant::cast(size);
} else {
size_upper_bound_ = NULL;
size_upper_bound_ = size_upper_bound;
}
}
@ -5611,7 +5611,7 @@ class HAllocate V8_FINAL : public HTemplateInstruction<2> {
allocate->IsOldPointerSpaceAllocation());
}
void ClearNextMapWord(int offset);
void ClearNextMapWord(HValue* offset);
Flags flags_;
Handle<Map> known_initial_map_;