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

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 27d064d3b4bbbdf355b9d8ca667a7f13b4259429..bf0bc94fbc7bc6f7e510133fec055ad3c6110d6a 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -164,13 +164,24 @@ bool LCodeGen::GeneratePrologue() {
   if (NeedsEagerFrame()) {
     ASSERT(!frame_is_built_);
     frame_is_built_ = true;
-    __ push(rbp);  // Caller's frame pointer.
-    __ movq(rbp, rsp);
-    __ push(rsi);  // Callee's context.
-    if (info()->IsStub()) {
-      __ Push(Smi::FromInt(StackFrame::STUB));
+    if (FLAG_optimize_for_size && FLAG_age_code && !info()->IsStub()) {
+        // Pre-age the code.
+      __ Call(isolate()->builtins()->MarkCodeAsExecutedOnce(),
+             RelocInfo::CODE_AGE_SEQUENCE);
+      for (int i = Assembler::kShortCallInstructionLength;
+           i < kNoCodeAgeSequenceLength;
+           i++) {
+        __ nop();
+      }
     } else {
-      __ push(rdi);  // Callee's JS function.
+      __ push(rbp);  // Caller's frame pointer.
+      __ movq(rbp, rsp);
+      __ push(rsi);  // Callee's context.
+      if (info()->IsStub()) {
+        __ Push(Smi::FromInt(StackFrame::STUB));
+      } else {
+        __ push(rdi);  // Callee's JS function.
+      }
     }
     info()->AddNoFrameRange(0, masm_->pc_offset());
   }