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Unified Diff: src/hydrogen-instructions.cc

Issue 22378003: Added allocation folding support for old space allocations. (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Created 7 years, 4 months ago
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Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index b0045b8751b06258f0a241416e54615924ea910f..8e0ed38921a2f6d1110b590e33a49ff6e0013f55 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -2366,6 +2366,24 @@ HConstant::HConstant(Handle<Object> handle,
}
+HConstant::HConstant(Handle<Map> handle,
+ UniqueValueId unique_id)
+ : HTemplateInstruction<0>(HType::Tagged()),
+ handle_(handle),
+ unique_id_(unique_id),
+ has_smi_value_(false),
+ has_int32_value_(false),
+ has_double_value_(false),
+ has_external_reference_value_(false),
+ is_internalized_string_(false),
+ is_not_in_new_space_(true),
+ is_cell_(false),
+ boolean_value_(false) {
+ ASSERT(!handle.is_null());
+ Initialize(Representation::Tagged());
+}
+
+
HConstant::HConstant(int32_t integer_value,
Representation r,
bool is_not_in_new_space,
@@ -3180,6 +3198,7 @@ Representation HUnaryMathOperation::RepresentationFromInputs() {
void HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
HValue* dominator) {
ASSERT(side_effect == kChangesNewSpacePromotion);
+ Zone* zone = block()->zone();
if (!FLAG_use_allocation_folding) return;
// Try to fold allocations together with their dominating allocations.
@@ -3191,22 +3210,34 @@ void HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
return;
}
- HAllocate* dominator_allocate_instr = HAllocate::cast(dominator);
- HValue* dominator_size = dominator_allocate_instr->size();
+ HAllocate* dominator_allocate = HAllocate::cast(dominator);
+ HValue* dominator_size = dominator_allocate->size();
HValue* current_size = size();
- // We can just fold allocations that are guaranteed in new space.
+
// TODO(hpayer): Add support for non-constant allocation in dominator.
- if (!IsNewSpaceAllocation() || !current_size->IsInteger32Constant() ||
- !dominator_allocate_instr->IsNewSpaceAllocation() ||
+ if (!current_size->IsInteger32Constant() ||
!dominator_size->IsInteger32Constant()) {
if (FLAG_trace_allocation_folding) {
- PrintF("#%d (%s) cannot fold into #%d (%s)\n",
+ PrintF("#%d (%s) cannot fold into #%d (%s), dynamic allocation size\n",
id(), Mnemonic(), dominator->id(), dominator->Mnemonic());
}
return;
}
+ dominator_allocate = GetFoldableDominator(dominator_allocate);
+ if (dominator_allocate == NULL) {
+ return;
+ }
+
+ ASSERT((IsNewSpaceAllocation() &&
+ dominator_allocate->IsNewSpaceAllocation()) ||
+ (IsOldDataSpaceAllocation() &&
+ dominator_allocate->IsOldDataSpaceAllocation()) ||
+ (IsOldPointerSpaceAllocation() &&
+ dominator_allocate->IsOldPointerSpaceAllocation()));
+
// First update the size of the dominator allocate instruction.
+ dominator_size = dominator_allocate->size();
int32_t dominator_size_constant =
HConstant::cast(dominator_size)->GetInteger32Constant();
int32_t current_size_constant =
@@ -3214,8 +3245,8 @@ void HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
int32_t new_dominator_size = dominator_size_constant + current_size_constant;
if (MustAllocateDoubleAligned()) {
- if (!dominator_allocate_instr->MustAllocateDoubleAligned()) {
- dominator_allocate_instr->MakeDoubleAligned();
+ if (!dominator_allocate->MustAllocateDoubleAligned()) {
+ dominator_allocate->MakeDoubleAligned();
}
if ((dominator_size_constant & kDoubleAlignmentMask) != 0) {
dominator_size_constant += kDoubleSize / 2;
@@ -3226,21 +3257,19 @@ void HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
if (new_dominator_size > Page::kMaxNonCodeHeapObjectSize) {
if (FLAG_trace_allocation_folding) {
PrintF("#%d (%s) cannot fold into #%d (%s) due to size: %d\n",
- id(), Mnemonic(), dominator->id(), dominator->Mnemonic(),
- new_dominator_size);
+ id(), Mnemonic(), dominator_allocate->id(),
+ dominator_allocate->Mnemonic(), new_dominator_size);
}
return;
}
- HBasicBlock* block = dominator->block();
- Zone* zone = block->zone();
- HInstruction* new_dominator_size_constant =
- HConstant::New(zone, context(), new_dominator_size);
- new_dominator_size_constant->InsertBefore(dominator_allocate_instr);
- dominator_allocate_instr->UpdateSize(new_dominator_size_constant);
+
+ HInstruction* new_dominator_size_constant = HConstant::CreateAndInsertBefore(
+ zone, context(), new_dominator_size, dominator_allocate);
+ dominator_allocate->UpdateSize(new_dominator_size_constant);
#ifdef VERIFY_HEAP
- if (FLAG_verify_heap) {
- dominator_allocate_instr->MakePrefillWithFiller();
+ if (FLAG_verify_heap && dominator_allocate->IsNewSpaceAllocation()) {
+ dominator_allocate->MakePrefillWithFiller();
}
#endif
@@ -3248,18 +3277,128 @@ void HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
HInstruction* dominated_allocate_instr =
HInnerAllocatedObject::New(zone,
context(),
- dominator_allocate_instr,
+ dominator_allocate,
dominator_size_constant,
type());
dominated_allocate_instr->InsertBefore(this);
DeleteAndReplaceWith(dominated_allocate_instr);
if (FLAG_trace_allocation_folding) {
PrintF("#%d (%s) folded into #%d (%s)\n",
- id(), Mnemonic(), dominator->id(), dominator->Mnemonic());
+ id(), Mnemonic(), dominator_allocate->id(),
+ dominator_allocate->Mnemonic());
}
}
+HAllocate* HAllocate::GetFoldableDominator(HAllocate* dominator) {
+ if (!IsFoldable(dominator)) {
+ // We cannot hoist old space allocations over new space allocations.
+ if (IsNewSpaceAllocation() || dominator->IsNewSpaceAllocation()) {
+ if (FLAG_trace_allocation_folding) {
+ PrintF("#%d (%s) cannot fold into #%d (%s), new space hoisting\n",
+ id(), Mnemonic(), dominator->id(), dominator->Mnemonic());
+ }
+ return NULL;
+ }
+
+ HAllocate* dominator_dominator = dominator->dominating_allocate_;
+
+ // We can hoist old data space allocations over an old pointer space
+ // allocation and vice versa. For that we have to check the dominator
+ // of the dominator allocate instruction.
+ if (dominator_dominator == NULL) {
+ dominating_allocate_ = dominator;
+ if (FLAG_trace_allocation_folding) {
+ PrintF("#%d (%s) cannot fold into #%d (%s), different spaces\n",
+ id(), Mnemonic(), dominator->id(), dominator->Mnemonic());
+ }
+ return NULL;
+ }
+
+ // We can just fold old space allocations that are in the same basic block,
+ // since it is not guaranteed that we fill up the whole allocated old
+ // space memory.
+ // TODO(hpayer): Remove this limitation and add filler maps for each each
+ // allocation as soon as we have store elimination.
+ if (block()->block_id() != dominator_dominator->block()->block_id()) {
+ if (FLAG_trace_allocation_folding) {
+ PrintF("#%d (%s) cannot fold into #%d (%s), different basic blocks\n",
+ id(), Mnemonic(), dominator_dominator->id(),
+ dominator_dominator->Mnemonic());
+ }
+ return NULL;
+ }
+
+ ASSERT((IsOldDataSpaceAllocation() &&
+ dominator_dominator->IsOldDataSpaceAllocation()) ||
+ (IsOldPointerSpaceAllocation() &&
+ dominator_dominator->IsOldPointerSpaceAllocation()));
+
+ int32_t current_size = HConstant::cast(size())->GetInteger32Constant();
+ HStoreNamedField* dominator_free_space_size =
+ dominator->filler_free_space_size_;
+ if (dominator_free_space_size != NULL) {
+ // We already hoisted one old space allocation, i.e., we already installed
+ // a filler map. Hence, we just have to update the free space size.
+ dominator->UpdateFreeSpaceFiller(current_size);
+ } else {
+ // This is the first old space allocation that gets hoisted. We have to
+ // install a filler map since the follwing allocation may cause a GC.
+ dominator->CreateFreeSpaceFiller(current_size);
+ }
+
+ // We can hoist the old space allocation over the actual dominator.
+ return dominator_dominator;
+ }
+ return dominator;
+}
+
+
+void HAllocate::UpdateFreeSpaceFiller(int32_t free_space_size) {
+ ASSERT(filler_free_space_size_ != NULL);
+ Zone* zone = block()->zone();
+ HConstant* new_free_space_size = HConstant::CreateAndInsertBefore(
+ zone,
+ context(),
+ filler_free_space_size_->value()->GetInteger32Constant() +
+ free_space_size,
+ filler_free_space_size_);
+ filler_free_space_size_->UpdateValue(new_free_space_size);
+}
+
+
+void HAllocate::CreateFreeSpaceFiller(int32_t free_space_size) {
+ ASSERT(filler_free_space_size_ == NULL);
+ Zone* zone = block()->zone();
+ int32_t dominator_size =
+ HConstant::cast(dominating_allocate_->size())->GetInteger32Constant();
+ HInstruction* free_space_instr =
+ HInnerAllocatedObject::New(zone, context(), dominating_allocate_,
+ dominator_size, type());
+ free_space_instr->InsertBefore(this);
+ HConstant* filler_map = HConstant::New(
+ zone,
+ context(),
+ isolate()->factory()->free_space_map(),
+ UniqueValueId(isolate()->heap()->free_space_map()));
+ filler_map->InsertAfter(free_space_instr);
+ HInstruction* store_map = HStoreNamedField::New(zone, context(),
+ free_space_instr, HObjectAccess::ForMap(), filler_map);
+ store_map->SetFlag(HValue::kHasNoObservableSideEffects);
+ store_map->InsertAfter(filler_map);
+
+ HConstant* filler_size = HConstant::CreateAndInsertAfter(
+ zone, context(), free_space_size, store_map);
+ HObjectAccess access =
+ HObjectAccess::ForJSObjectOffset(FreeSpace::kSizeOffset);
+ HStoreNamedField* store_size = HStoreNamedField::New(zone, context(),
+ free_space_instr, access, filler_size);
+ store_size->SetFlag(HValue::kHasNoObservableSideEffects);
+ store_size->InsertAfter(filler_size);
+ filler_free_space_size_ = store_size;
+}
+
+
void HAllocate::PrintDataTo(StringStream* stream) {
size()->PrintNameTo(stream);
stream->Add(" (");
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