Implemented function that returns code age.

src/mark-compact.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 986 matching lines @@
     next_candidate = GetNextCandidate(candidate);
     ClearNextCandidate(candidate, undefined);
 
     SharedFunctionInfo* shared = candidate->shared();
 
     Code* code = shared->code();
     MarkBit code_mark = Marking::MarkBitFrom(code);
     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);
+        int age = FLAG_age_code ? code->GetAge() : shared->code_age();
+        PrintF("[code-flushing clears: %s - age: %d]\n", *name, age);

[Michael Starzinger, 2013/06/11 17:30:07]

Won't this age be constant since we at a certain age and the code-flusher should
be active all the time in normal execution (i.e. without attached debugger)
anyways?

[Hannes Payer (out of office), 2013/06/12 08:56:32]

True, an assert is more appropriate.

       }
       shared->set_code(lazy_compile);
       candidate->set_code(lazy_compile);
     } else {
       candidate->set_code(code);
     }
 
     // We are in the middle of a GC cycle so the write barrier in the code
     // setter did not record the slot update and we have to do that manually.
     Address slot = candidate->address() + JSFunction::kCodeEntryOffset;
@@ skipping 20 matching lines @@
   SharedFunctionInfo* next_candidate;
   while (candidate != NULL) {
     next_candidate = GetNextCandidate(candidate);
     ClearNextCandidate(candidate);
 
     Code* code = candidate->code();
     MarkBit code_mark = Marking::MarkBitFrom(code);
     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);
+        int age = FLAG_age_code ? code->GetAge() : candidate->code_age();
+        PrintF("[code-flushing clears: %s - age: %d]\n", *name, age);
       }
       candidate->set_code(lazy_compile);
     }
 
     Object** code_slot =
         HeapObject::RawField(candidate, SharedFunctionInfo::kCodeOffset);
     isolate_->heap()->mark_compact_collector()->
         RecordSlot(code_slot, code_slot, *code_slot);
 
     candidate = next_candidate;
@@ skipping 66 matching lines @@
   optimized_code_map_holder_head_ = NULL;
 }
 
 
 void CodeFlusher::EvictCandidate(SharedFunctionInfo* shared_info) {
   // Make sure previous flushing decisions are revisited.
   isolate_->heap()->incremental_marking()->RecordWrites(shared_info);
 
   if (FLAG_trace_code_flushing) {
     SmartArrayPointer<char> name = shared_info->DebugName()->ToCString();
-    PrintF("[code-flushing abandons function-info: %s]\n", *name);
+    int age = FLAG_age_code ?
+        shared_info->code()->GetAge() : shared_info->code_age();
+    PrintF("[code-flushing abandons function-info: %s - age: %d]\n",
+        *name, age);
   }
 
   SharedFunctionInfo* candidate = shared_function_info_candidates_head_;
   SharedFunctionInfo* next_candidate;
   if (candidate == shared_info) {
     next_candidate = GetNextCandidate(shared_info);
     shared_function_info_candidates_head_ = next_candidate;
     ClearNextCandidate(shared_info);
   } else {
     while (candidate != NULL) {
@@ skipping 15 matching lines @@
 void CodeFlusher::EvictCandidate(JSFunction* function) {
   ASSERT(!function->next_function_link()->IsUndefined());
   Object* undefined = isolate_->heap()->undefined_value();
 
   // Make sure previous flushing decisions are revisited.
   isolate_->heap()->incremental_marking()->RecordWrites(function);
   isolate_->heap()->incremental_marking()->RecordWrites(function->shared());
 
   if (FLAG_trace_code_flushing) {
     SmartArrayPointer<char> name = function->shared()->DebugName()->ToCString();
-    PrintF("[code-flushing abandons closure: %s]\n", *name);
+    int age = FLAG_age_code ?
+        function->shared()->code()->GetAge() : function->shared()->code_age();
+    PrintF("[code-flushing abandons closure: %s - age: %d]\n", *name, age);
   }
 
   JSFunction* candidate = jsfunction_candidates_head_;
   JSFunction* next_candidate;
   if (candidate == function) {
     next_candidate = GetNextCandidate(function);
     jsfunction_candidates_head_ = next_candidate;
     ClearNextCandidate(function, undefined);
   } else {
     while (candidate != NULL) {
@@ skipping 3083 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal