Track JS allocations as they arrive with no affection on performance when tracking is switched off

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 74e3fcc33a1701d4a1836090188de51776bc22f5..40f132a019eb0b1034e084497eda12ac23105669 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -3858,6 +3858,8 @@ void MacroAssembler::Allocate(int object_size,
   // Load address of new object into result.
   LoadAllocationTopHelper(result, scratch, flags);
 
+  RecordObjectAllocation(isolate(), result, object_size);
+
   // Align the next allocation. Storing the filler map without checking top is
   // safe in new-space because the limit of the heap is aligned there.
   if (((flags & DOUBLE_ALIGNMENT) != 0) && FLAG_debug_code) {
@@ -3937,6 +3939,8 @@ void MacroAssembler::Allocate(Register object_size,
   // Load address of new object into result.
   LoadAllocationTopHelper(result, scratch, flags);
 
+  RecordObjectAllocation(isolate(), result, object_size);
+
   // Align the next allocation. Storing the filler map without checking top is
   // safe in new-space because the limit of the heap is aligned there.
   if (((flags & DOUBLE_ALIGNMENT) != 0) && FLAG_debug_code) {
@@ -4698,6 +4702,50 @@ void MacroAssembler::TestJSArrayForAllocationMemento(
 }
 
 
+void MacroAssembler::RecordObjectAllocation(Isolate* isolate,
+                                            Register object,
+                                            Register object_size) {
+  Label done;
+  cmpb(ExternalOperand(

[Hannes Payer (out of office), 2013/08/28 10:35:05]

I am concerned about the performance impact of that. 

+           ExternalReference::is_tracking_allocations_address(isolate)),
+       Immediate(0));
+  j(zero, &done, Label::kNear);
+  FrameScope frame(this, StackFrame::MANUAL);
+  PushSafepointRegisters();
+  PrepareCallCFunction(3);
+  // In case object is rdx
+  movq(kScratchRegister, object);
+  movq(arg_reg_3, object_size);
+  movq(arg_reg_2, kScratchRegister);
+  movq(arg_reg_1, isolate, RelocInfo::EXTERNAL_REFERENCE);
+  CallCFunction(
+      ExternalReference::record_object_allocation_function(isolate), 3);
+  PopSafepointRegisters();
+  bind(&done);
+}
+
+
+void MacroAssembler::RecordObjectAllocation(Isolate* isolate,
+                                            Register object,
+                                            int object_size) {
+  Label done;
+  cmpb(ExternalOperand(
+           ExternalReference::is_tracking_allocations_address(isolate)),
+       Immediate(0));
+  j(zero, &done, Label::kNear);
+  FrameScope frame(this, StackFrame::MANUAL);
+  PushSafepointRegisters();
+  PrepareCallCFunction(3);
+  movq(arg_reg_2, object);
+  movq(arg_reg_3, Immediate(object_size));
+  movq(arg_reg_1, isolate, RelocInfo::EXTERNAL_REFERENCE);
+  CallCFunction(
+      ExternalReference::record_object_allocation_function(isolate), 3);
+  PopSafepointRegisters();
+  bind(&done);
+}
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64