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

src/x64/assembler-x64-inl.h

Index: src/x64/assembler-x64-inl.h
diff --git a/src/x64/assembler-x64-inl.h b/src/x64/assembler-x64-inl.h
index 07d07033e9546b1b6a6b5086c6817532a8598d10..4887899b506137eb674b57e987a1734148164392 100644
--- a/src/x64/assembler-x64-inl.h
+++ b/src/x64/assembler-x64-inl.h
@@ -43,6 +43,7 @@ namespace internal {
 
 
 static const byte kCallOpcode = 0xE8;
+static const int kNoCodeAgeSequenceLength = 6;
 
 
 void Assembler::emitl(uint32_t x) {
@@ -79,7 +80,8 @@ void Assembler::emitw(uint16_t x) {
 void Assembler::emit_code_target(Handle<Code> target,
                                  RelocInfo::Mode rmode,
                                  TypeFeedbackId ast_id) {
-  ASSERT(RelocInfo::IsCodeTarget(rmode));
+  ASSERT(RelocInfo::IsCodeTarget(rmode) ||
+      rmode == RelocInfo::CODE_AGE_SEQUENCE);
   if (rmode == RelocInfo::CODE_TARGET && !ast_id.IsNone()) {
     RecordRelocInfo(RelocInfo::CODE_TARGET_WITH_ID, ast_id.ToInt());
   } else {
@@ -392,6 +394,13 @@ bool RelocInfo::IsPatchedDebugBreakSlotSequence() {
 }
 
 
+Handle<Object> RelocInfo::code_age_stub_handle(Assembler* origin) {
+  ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
+  ASSERT(*pc_ == kCallOpcode);
+  return origin->code_target_object_handle_at(pc_ + 1);
+}
+
+
 Code* RelocInfo::code_age_stub() {
   ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
   ASSERT(*pc_ == kCallOpcode);