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Unified Diff: src/ia32/macro-assembler-ia32.cc

Issue 1845463003: Remove usages of Heap::NewSpaceStart and its external reference (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: Only use 1 constant, reordered checks a bit to have earlier bail outs for old space Created 4 years, 9 months ago
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Index: src/ia32/macro-assembler-ia32.cc
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index 556e71076b2ce54919416e547f8e349a365277b1..b1c16f2357891f567363bd287f8d2da95b9f7e9e 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -3327,19 +3327,40 @@ void MacroAssembler::TestJSArrayForAllocationMemento(
Register receiver_reg,
Register scratch_reg,
Label* no_memento_found) {
- ExternalReference new_space_start =
- ExternalReference::new_space_start(isolate());
+ Label map_check;
+ Label top_check;
ExternalReference new_space_allocation_top =
ExternalReference::new_space_allocation_top_address(isolate());
-
- lea(scratch_reg, Operand(receiver_reg,
- JSArray::kSize + AllocationMemento::kSize - kHeapObjectTag));
- cmp(scratch_reg, Immediate(new_space_start));
- j(less, no_memento_found);
+ const int kMementoMapOffset = JSArray::kSize - kHeapObjectTag;
+ const int kMementoEndOffset = kMementoMapOffset + AllocationMemento::kSize;
+
+ // Bail out if the object is not in new space.
+ JumpIfNotInNewSpace(receiver_reg, scratch_reg, no_memento_found);
+ // If the object is in new space, we need to check whether it is on the same
+ // page as the current top.
+ lea(scratch_reg, Operand(receiver_reg, kMementoEndOffset));
+ xor_(scratch_reg, Operand::StaticVariable(new_space_allocation_top));
+ test(scratch_reg, Immediate(~Page::kPageAlignmentMask));
+ j(zero, &top_check);
+ // The object is on a different page than allocation top. Bail out if the
+ // object sits on the page boundary as no memento can follow and we cannot
+ // touch the memory following it.
+ lea(scratch_reg, Operand(receiver_reg, kMementoEndOffset));
+ xor_(scratch_reg, receiver_reg);
+ test(scratch_reg, Immediate(~Page::kPageAlignmentMask));
+ j(not_zero, no_memento_found);
+ // Continue with the actual map check.
+ jmp(&map_check);
+ // If top is on the same page as the current object, we need to check whether
+ // we are below top.
+ bind(&top_check);
+ lea(scratch_reg, Operand(receiver_reg, kMementoEndOffset));
cmp(scratch_reg, Operand::StaticVariable(new_space_allocation_top));
j(greater, no_memento_found);
- cmp(MemOperand(scratch_reg, -AllocationMemento::kSize),
- Immediate(isolate()->factory()->allocation_memento_map()));
+ // Memento map check.
+ bind(&map_check);
+ mov(scratch_reg, Operand(receiver_reg, kMementoMapOffset));
+ cmp(scratch_reg, Immediate(isolate()->factory()->allocation_memento_map()));
}
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