Reviewers: danno, Benedikt Meurer, Paul Lind, kisg, palfia, dusmil,
Description:
MIPS: Skip write barriers in the fast case when setting up local context.
Port r21481 (5973b48)
Original commit message:
The FastNewContextStub always allocates in new space, so we don't
need to update the write barrier when copying the parameters to
the newly allocated context.
BUG=
Please review this at https://codereview.chromium.org/302633002/
SVN Base: https://github.com/v8/v8.git@gbl
Affected files (+24, -4 lines):
M src/mips/full-codegen-mips.cc
M src/mips/lithium-codegen-mips.cc
Index: src/mips/full-codegen-mips.cc
diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index
5a47a7ce46e4f0ffe9c95d11cb8a07c16a7eb0b9..7310eee88a4e2ec7952cd6346403b109cf928447
100644
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -219,6 +219,7 @@ void FullCodeGenerator::Generate() {
if (heap_slots > 0) {
Comment cmnt(masm_, "[ Allocate context");
// Argument to NewContext is the function, which is still in a1.
+ bool need_write_barrier = true;
if (FLAG_harmony_scoping && info->scope()->is_global_scope()) {
__ push(a1);
__ Push(info->scope()->GetScopeInfo());
@@ -226,6 +227,8 @@ void FullCodeGenerator::Generate() {
} else if (heap_slots <= FastNewContextStub::kMaximumSlots) {
FastNewContextStub stub(isolate(), heap_slots);
__ CallStub(&stub);
+ // Result of FastNewContextStub is always in new space.
+ need_write_barrier = false;
} else {
__ push(a1);
__ CallRuntime(Runtime::kHiddenNewFunctionContext, 1);
@@ -249,8 +252,15 @@ void FullCodeGenerator::Generate() {
__ sw(a0, target);
// Update the write barrier.
- __ RecordWriteContextSlot(
- cp, target.offset(), a0, a3, kRAHasBeenSaved, kDontSaveFPRegs);
+ if (need_write_barrier) {
+ __ RecordWriteContextSlot(
+ cp, target.offset(), a0, a3, kRAHasBeenSaved,
kDontSaveFPRegs);
+ } else if (FLAG_debug_code) {
+ Label done;
+ __ JumpIfInNewSpace(cp, a0, &done);
+ __ Abort(kExpectedNewSpaceObject);
+ __ bind(&done);
+ }
}
}
}
Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc
b/src/mips/lithium-codegen-mips.cc
index
fd30b1a8fff050f52f90ee93b03648c017f7afd1..f1deb387059d6071fc698ce172b3199cf3d2be94
100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -198,10 +198,13 @@ bool LCodeGen::GeneratePrologue() {
int heap_slots = info()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
if (heap_slots > 0) {
Comment(";;; Allocate local context");
+ bool need_write_barrier = true;
// Argument to NewContext is the function, which is in a1.
if (heap_slots <= FastNewContextStub::kMaximumSlots) {
FastNewContextStub stub(isolate(), heap_slots);
__ CallStub(&stub);
+ // Result of FastNewContextStub is always in new space.
+ need_write_barrier = false;
} else {
__ push(a1);
__ CallRuntime(Runtime::kHiddenNewFunctionContext, 1);
@@ -224,8 +227,15 @@ bool LCodeGen::GeneratePrologue() {
MemOperand target = ContextOperand(cp, var->index());
__ sw(a0, target);
// Update the write barrier. This clobbers a3 and a0.
- __ RecordWriteContextSlot(
- cp, target.offset(), a0, a3, GetRAState(), kSaveFPRegs);
+ if (need_write_barrier) {
+ __ RecordWriteContextSlot(
+ cp, target.offset(), a0, a3, GetRAState(), kSaveFPRegs);
+ } else if (FLAG_debug_code) {
+ Label done;
+ __ JumpIfInNewSpace(cp, a0, &done);
+ __ Abort(kExpectedNewSpaceObject);
+ __ bind(&done);
+ }
}
}
Comment(";;; End allocate local context");
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