Enable preaging of code objects when --optimize-for-size.

src/objects.cc

 // Copyright 2013 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 10253 matching lines @@
     } else if (RelocInfo::IsCodeTarget(mode)) {
       // rewrite code handles in inline cache targets to direct
       // pointers to the first instruction in the code object
       Handle<Object> p = it.rinfo()->target_object_handle(origin);
       Code* code = Code::cast(*p);
       it.rinfo()->set_target_address(code->instruction_start(),
                                      SKIP_WRITE_BARRIER);
     } else if (RelocInfo::IsRuntimeEntry(mode)) {
       Address p = it.rinfo()->target_runtime_entry(origin);
       it.rinfo()->set_target_runtime_entry(p, SKIP_WRITE_BARRIER);
+    } else if (mode == RelocInfo::CODE_AGE_SEQUENCE) {
+      Handle<Object> p = it.rinfo()->code_age_stub_handle(origin);
+      Code* code = Code::cast(*p);
+      it.rinfo()->set_code_age_stub(code);
     } else {
       it.rinfo()->apply(delta);
     }
   }
   CPU::FlushICache(instruction_start(), instruction_size());
 }
 
 
 // Locate the source position which is closest to the address in the code. This
 // is using the source position information embedded in the relocation info.
@@ skipping 221 matching lines @@
   }
   return BailoutId::None();
 }
 
 
 void Code::MakeCodeAgeSequenceYoung(byte* sequence, Isolate* isolate) {
   PatchPlatformCodeAge(isolate, sequence, kNoAge, NO_MARKING_PARITY);
 }
 
 
+void Code::MarkCodeAsExecuted(byte* sequence, Isolate* isolate) {
+  PatchPlatformCodeAge(isolate, sequence, kExecutedOnceCodeAge,
+      NO_MARKING_PARITY);
+}
+
+
 void Code::MakeOlder(MarkingParity current_parity) {
   byte* sequence = FindCodeAgeSequence();
   if (sequence != NULL) {
     Age age;
     MarkingParity code_parity;
     GetCodeAgeAndParity(sequence, &age, &code_parity);
     if (age != kLastCodeAge && code_parity != current_parity) {
       PatchPlatformCodeAge(GetIsolate(),
                            sequence,
                            static_cast<Age>(age + 1),
                            current_parity);
     }
   }
 }
 
 
 bool Code::IsOld() {
-  byte* sequence = FindCodeAgeSequence();
-  if (sequence == NULL) return false;
-  Age age;
-  MarkingParity parity;
-  GetCodeAgeAndParity(sequence, &age, &parity);
-  return age >= kSexagenarianCodeAge;
+  Age age = GetAge();
+  return age >= kIsOldCodeAge;
 }
 
 
 byte* Code::FindCodeAgeSequence() {
   return FLAG_age_code &&
-      prologue_offset() != kPrologueOffsetNotSet &&
+      prologue_offset() != Code::kPrologueOffsetNotSet &&
       (kind() == OPTIMIZED_FUNCTION ||
        (kind() == FUNCTION && !has_debug_break_slots()))
       ? instruction_start() + prologue_offset()
       : NULL;
 }
 
 
-int Code::GetAge() {
+Code::Age Code::GetAge() {
   byte* sequence = FindCodeAgeSequence();
   if (sequence == NULL) {
     return Code::kNoAge;
   }
   Age age;
   MarkingParity parity;
   GetCodeAgeAndParity(sequence, &age, &parity);
   return age;
 }
 
@@ skipping 11 matching lines @@
     return;                                                             \
   }                                                                     \
   stub = *builtins->Make##AGE##CodeYoungAgainOddMarking();              \
   if (code == stub) {                                                   \
     *age = k##AGE##CodeAge;                                             \
     *parity = ODD_MARKING_PARITY;                                       \
     return;                                                             \
   }
   CODE_AGE_LIST(HANDLE_CODE_AGE)
 #undef HANDLE_CODE_AGE
+  stub = *builtins->MarkCodeAsExecutedOnce();
+  if (code == stub) {
+    // Treat that's never been executed as old immediatly.
+    *age = kIsOldCodeAge;
+    *parity = NO_MARKING_PARITY;
+    return;
+  }
+  stub = *builtins->MarkCodeAsExecutedTwice();
+  if (code == stub) {
+    // Pre-age code that has only been executed once.
+    *age = kPreAgedCodeAge;
+    *parity = NO_MARKING_PARITY;
+    return;
+  }
   UNREACHABLE();
 }
 
 
 Code* Code::GetCodeAgeStub(Isolate* isolate, Age age, MarkingParity parity) {
   Builtins* builtins = isolate->builtins();
   switch (age) {
 #define HANDLE_CODE_AGE(AGE)                                            \
     case k##AGE##CodeAge: {                                             \
       Code* stub = parity == EVEN_MARKING_PARITY                        \
           ? *builtins->Make##AGE##CodeYoungAgainEvenMarking()           \
           : *builtins->Make##AGE##CodeYoungAgainOddMarking();           \
       return stub;                                                      \
     }
     CODE_AGE_LIST(HANDLE_CODE_AGE)
 #undef HANDLE_CODE_AGE
+    case kNotExecutedCodeAge: {
+      ASSERT(parity == NO_MARKING_PARITY);
+      return *builtins->MarkCodeAsExecutedOnce();
+    }
+    case kExecutedOnceCodeAge: {
+      ASSERT(parity == NO_MARKING_PARITY);
+      return *builtins->MarkCodeAsExecutedTwice();
+    }
     default:
       UNREACHABLE();
       break;
   }
   return NULL;
 }
 
 
 void Code::PrintDeoptLocation(int bailout_id) {
   const char* last_comment = NULL;
@@ skipping 5652 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal