Implemented function that returns code age.

This may be used to display debugging information.

BUG=
R=danno@chromium.org, mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/16509005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15083 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mark-compact.cc

@@ -1004,7 +1004,7 @@ void CodeFlusher::ProcessJSFunctionCandidates() {
     if (!code_mark.Get()) {
       if (FLAG_trace_code_flushing && shared->is_compiled()) {
         SmartArrayPointer<char> name = shared->DebugName()->ToCString();
-        PrintF("[code-flushing clears: %s]\n", *name);
+        PrintF("[code-flushing clears: %s - age: %d]\n", *name, code->GetAge());
       }
       shared->set_code(lazy_compile);
       candidate->set_code(lazy_compile);
@@ -1045,7 +1045,7 @@ void CodeFlusher::ProcessSharedFunctionInfoCandidates() {
     if (!code_mark.Get()) {
       if (FLAG_trace_code_flushing && candidate->is_compiled()) {
         SmartArrayPointer<char> name = candidate->DebugName()->ToCString();
-        PrintF("[code-flushing clears: %s]\n", *name);
+        PrintF("[code-flushing clears: %s - age: %d]\n", *name, code->GetAge());
       }
       candidate->set_code(lazy_compile);
     }

src/objects.cc

@@ -10299,6 +10299,18 @@ byte* Code::FindCodeAgeSequence() {
 }
 
 
+int Code::GetAge() {
+  byte* sequence = FindCodeAgeSequence();
+  if (sequence == NULL) {
+    return Code::kNoAge;
+  }
+  Age age;
+  MarkingParity parity;
+  GetCodeAgeAndParity(sequence, &age, &parity);
+  return age;
+}
+
+
 void Code::GetCodeAgeAndParity(Code* code, Age* age,
                                MarkingParity* parity) {
   Isolate* isolate = Isolate::Current();

src/objects.h

@@ -4825,6 +4825,7 @@ class Code: public HeapObject {
   void MakeOlder(MarkingParity);
   static bool IsYoungSequence(byte* sequence);
   bool IsOld();
+  int GetAge();
 
   void PrintDeoptLocation(int bailout_id);
 
@@ -4966,8 +4967,8 @@ class Code: public HeapObject {
 
   // Code aging
   byte* FindCodeAgeSequence();
-  static void  GetCodeAgeAndParity(Code* code, Age* age,
-                                   MarkingParity* parity);
+  static void GetCodeAgeAndParity(Code* code, Age* age,
+                                  MarkingParity* parity);
   static void GetCodeAgeAndParity(byte* sequence, Age* age,
                                   MarkingParity* parity);
   static Code* GetCodeAgeStub(Age age, MarkingParity parity);