Reviewers: mvstanton, Michael Starzinger,
Description:
Clear next map word when folding allocations into js arrays.
BUG=
Please review this at https://codereview.chromium.org/22915007/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/hydrogen-instructions.h
M src/hydrogen-instructions.cc
M test/mjsunit/allocation-folding.js
Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index
b0045b8751b06258f0a241416e54615924ea910f..61eb1a098c58bfe6364a6fbf03c5bbf035e16969
100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -3209,6 +3209,7 @@ void HAllocate::HandleSideEffectDominator(GVNFlag
side_effect,
// First update the size of the dominator allocate instruction.
int32_t dominator_size_constant =
HConstant::cast(dominator_size)->GetInteger32Constant();
+ int32_t object_offset = dominator_size_constant;
int32_t current_size_constant =
HConstant::cast(current_size)->GetInteger32Constant();
int32_t new_dominator_size = dominator_size_constant +
current_size_constant;
@@ -3238,6 +3239,20 @@ void HAllocate::HandleSideEffectDominator(GVNFlag
side_effect,
new_dominator_size_constant->InsertBefore(dominator_allocate_instr);
dominator_allocate_instr->UpdateSize(new_dominator_size_constant);
+ // TODO(hpayer): This is a short-term hack to make allocation mementos
+ // work again in new space.
+ if (dominator_allocate_instr->type().Equals(HType::JSArray()) &&
+ !dominator_allocate_instr->clear_next_map_word_) {
+ HObjectAccess access =
+ HObjectAccess::ForJSObjectOffset(object_offset);
+ HStoreNamedField* clear_next_map =
+ HStoreNamedField::New(zone, context(), dominator_allocate_instr,
access,
+ block->graph()->GetConstantNull());
+ clear_next_map->ClearAllSideEffects();
+ clear_next_map->InsertAfter(dominator_allocate_instr);
+ dominator_allocate_instr->clear_next_map_word_ = true;
+ }
+
#ifdef VERIFY_HEAP
if (FLAG_verify_heap) {
dominator_allocate_instr->MakePrefillWithFiller();
Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index
685a5e883cd4085e231cd2d2b2f99c9a8f863dde..d0d5886c8597446cdc698ccc4e970d40caa56805
100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -5126,7 +5126,8 @@ class HAllocate V8_FINAL : public
HTemplateInstruction<2> {
HType type,
PretenureFlag pretenure_flag,
InstanceType instance_type)
- : HTemplateInstruction<2>(type) {
+ : HTemplateInstruction<2>(type),
+ clear_next_map_word_(false) {
SetOperandAt(0, context);
SetOperandAt(1, size);
set_representation(Representation::Tagged());
@@ -5145,6 +5146,7 @@ class HAllocate V8_FINAL : public
HTemplateInstruction<2> {
Flags flags_;
Handle<Map> known_initial_map_;
+ bool clear_next_map_word_;
};
Index: test/mjsunit/allocation-folding.js
diff --git a/test/mjsunit/allocation-folding.js
b/test/mjsunit/allocation-folding.js
index
fe5fa6d855e5894c2a3f136db2c14a3a865fbe40..f57de11d533f8137ff1ce9e6f8fb98b8af665c39
100644
--- a/test/mjsunit/allocation-folding.js
+++ b/test/mjsunit/allocation-folding.js
@@ -56,7 +56,7 @@ function doubles() {
doubles(); doubles(); doubles();
%OptimizeFunctionOnNextCall(doubles);
-var result = doubles();
+result = doubles();
gc();
@@ -72,8 +72,31 @@ function doubles_int() {
doubles_int(); doubles_int(); doubles_int();
%OptimizeFunctionOnNextCall(doubles_int);
-var result = doubles_int();
+result = doubles_int();
gc();
assertEquals(result[1], 3.1);
+
+// Test allocation folding of over a branch.
+
+function branch_int(left) {
+ var elem1 = [1, 2];
+ var elem2;
+ if (left) {
+ elem2 = [3, 4];
+ } else {
+ elem2 = [5, 6];
+ }
+ return elem2;
+}
+
+branch_int(1); branch_int(1); branch_int(1);
+%OptimizeFunctionOnNextCall(branch_int);
+result = branch_int(1);
+var result2 = branch_int(0);
+
+gc();
+
+assertEquals(result[1], 4);
+assertEquals(result2[1], 6);
--
--
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