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

src/x64/macro-assembler-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3840 matching lines @@
       }
     }
     jmp(gc_required);
     return;
   }
   ASSERT(!result.is(result_end));
 
   // 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) {
     testq(result, Immediate(kDoubleAlignmentMask));
     Check(zero, kAllocationIsNotDoubleAligned);
   }
 
   // Calculate new top and bail out if new space is exhausted.
   ExternalReference allocation_limit =
       AllocationUtils::GetAllocationLimitReference(isolate(), flags);
@@ skipping 59 matching lines @@
       // object_size is left unchanged by this function.
     }
     jmp(gc_required);
     return;
   }
   ASSERT(!result.is(result_end));
 
   // 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) {
     testq(result, Immediate(kDoubleAlignmentMask));
     Check(zero, kAllocationIsNotDoubleAligned);
   }
 
   // Calculate new top and bail out if new space is exhausted.
   ExternalReference allocation_limit =
       AllocationUtils::GetAllocationLimitReference(isolate(), flags);
@@ skipping 741 matching lines @@
   cmpq(scratch_reg, kScratchRegister);
   j(less, &no_memento_available);
   cmpq(scratch_reg, ExternalOperand(new_space_allocation_top));
   j(greater, &no_memento_available);
   CompareRoot(MemOperand(scratch_reg, -AllocationMemento::kSize),
               Heap::kAllocationMementoMapRootIndex);
   bind(&no_memento_available);
 }
 
 
+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