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

src/x64/macro-assembler-x64.h

 // 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 1031 matching lines @@
                                 Register key,
                                 Register r0,
                                 Register r1,
                                 Register r2,
                                 Register result);
 
 
   // ---------------------------------------------------------------------------
   // Allocation support
 
+  void RecordObjectAllocation(Isolate* isolate,
+                              Register object,
+                              Register object_size);
+
+  void RecordObjectAllocation(Isolate* isolate,
+                              Register object,
+                              int object_size);

[Hannes Payer (out of office), 2013/08/28 09:51:32]

Can we move these methods after the Allocate(...) methods and add a comment.

[Alexandra Mikhaylova, 2013/09/19 16:03:38]

Done.

+
   // Allocate an object in new space or old pointer space. If the given space
   // is exhausted control continues at the gc_required label. The allocated
   // object is returned in result and end of the new object is returned in
   // result_end. The register scratch can be passed as no_reg in which case
   // an additional object reference will be added to the reloc info. The
   // returned pointers in result and result_end have not yet been tagged as
   // heap objects. If result_contains_top_on_entry is true the content of
   // result is known to be the allocation top on entry (could be result_end
   // from a previous call). If result_contains_top_on_entry is true scratch
   // should be no_reg as it is never used.
@@ skipping 481 matching lines @@
     masm->popfq();                                                           \
   }                                                                          \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_