Fix for 3303 MultithreadedParallelIsolates has a race condition.

src/arm64/codegen-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "codegen.h"
 #include "macro-assembler.h"
@@ skipping 332 matching lines @@
   __ Pop(lr);
 
   __ Bind(&only_change_map);
   __ Str(target_map, FieldMemOperand(receiver, HeapObject::kMapOffset));
   __ RecordWriteField(receiver, HeapObject::kMapOffset, target_map, x13,
                       kLRHasNotBeenSaved, kDontSaveFPRegs, OMIT_REMEMBERED_SET,
                       OMIT_SMI_CHECK);
 }
 
 
-bool Code::IsYoungSequence(byte* sequence) {
-  return MacroAssembler::IsYoungSequence(sequence);
+CodeAgingHelper::CodeAgingHelper() {
+  ASSERT(young_sequence_.length() == kNoCodeAgeSequenceLength);
+  // The sequence of instructions that is patched out for aging code is the
+  // following boilerplate stack-building prologue that is found both in
+  // FUNCTION and OPTIMIZED_FUNCTION code:
+  PatchingAssembler patcher(young_sequence_.start(),
+                            young_sequence_.length() / kInstructionSize);
+  // The young sequence is the frame setup code for FUNCTION code types. It is
+  // generated by FullCodeGenerator::Generate.
+  MacroAssembler::EmitFrameSetupForCodeAgePatching(&patcher);
+
+#ifdef DEBUG
+  const int length = kCodeAgeStubEntryOffset / kInstructionSize;
+  ASSERT(old_sequence_.length() >= kCodeAgeStubEntryOffset);
+  PatchingAssembler patcher_old(old_sequence_.start(), length);
+  MacroAssembler::EmitCodeAgeSequence(&patcher_old, NULL);
+#endif
 }
 
 
-void Code::GetCodeAgeAndParity(byte* sequence, Age* age,
+#ifdef DEBUG
+bool CodeAgingHelper::IsOld(byte* candidate) const {
+  return memcmp(candidate, old_sequence_.start(), kCodeAgeStubEntryOffset) == 0;
+}
+#endif
+
+
+bool Code::IsYoungSequence(Isolate* isolate, byte* sequence) {
+  return MacroAssembler::IsYoungSequence(isolate, sequence);
+}
+
+
+void Code::GetCodeAgeAndParity(Isolate* isolate, byte* sequence, Age* age,
                                MarkingParity* parity) {
-  if (IsYoungSequence(sequence)) {
+  if (IsYoungSequence(isolate, sequence)) {
     *age = kNoAgeCodeAge;
     *parity = NO_MARKING_PARITY;
   } else {
     byte* target = sequence + kCodeAgeStubEntryOffset;
     Code* stub = GetCodeFromTargetAddress(Memory::Address_at(target));
     GetCodeAgeAndParity(stub, age, parity);
   }
 }
 
 
 void Code::PatchPlatformCodeAge(Isolate* isolate,
                                 byte* sequence,
                                 Code::Age age,
                                 MarkingParity parity) {
-  PatchingAssembler patcher(sequence, kCodeAgeSequenceSize / kInstructionSize);
+  PatchingAssembler patcher(sequence,
+                            kNoCodeAgeSequenceLength / kInstructionSize);
   if (age == kNoAgeCodeAge) {
     MacroAssembler::EmitFrameSetupForCodeAgePatching(&patcher);
   } else {
     Code * stub = GetCodeAgeStub(isolate, age, parity);
     MacroAssembler::EmitCodeAgeSequence(&patcher, stub);
   }
 }
 
 
 void StringCharLoadGenerator::Generate(MacroAssembler* masm,
@@ skipping 197 matching lines @@
   __ Fmul(result, double_temp3, double_temp1);
 
   __ Bind(&done);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64