From 4fd78904be3edda9e9c0e3b8e591125308649e1b Mon Sep 17 00:00:00 2001 From: "plind44@gmail.com" Date: Mon, 26 May 2014 14:40:55 +0000 Subject: [PATCH] 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= R=plind44@gmail.com Review URL: https://codereview.chromium.org/302633002 Patch from Balazs Kilvady . git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21500 ce2b1a6d-e550-0410-aec6-3dcde31c8c00 --- src/mips/full-codegen-mips.cc | 14 ++++++++++++-- src/mips/lithium-codegen-mips.cc | 14 ++++++++++++-- 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc index 5a47a7c..7310eee 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); + } } } } diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc index fd30b1a..f1deb38 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"); -- 2.7.4