Write barrier for storing a code entry, and usage in CompileLazy builtin.

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index a4851db55809eee9c48f770233a0c7c5d0d47c9d..db56b0092d926ce9ee1a2ec721ea175851e3b15a 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -982,6 +982,8 @@ void Builtins::Generate_CompileLazy(MacroAssembler* masm) {
   Label install_optimized_code_and_tailcall;
   __ bind(&install_optimized_code_and_tailcall);
   __ movp(FieldOperand(closure, JSFunction::kCodeEntryOffset), entry);
+  __ movp(rbx, entry);
+  __ RecordWriteCodeEntryField(closure, rbx, rax);
 
   // Link the closure into the optimized function list.
   // rcx : code entry (entry)
@@ -1036,6 +1038,8 @@ void Builtins::Generate_CompileLazy(MacroAssembler* masm) {
   // Yes, install the full code.
   __ leap(entry, FieldOperand(entry, Code::kHeaderSize));
   __ movp(FieldOperand(closure, JSFunction::kCodeEntryOffset), entry);
+  __ movp(rbx, entry);
+  __ RecordWriteCodeEntryField(closure, rbx, rax);
   __ jmp(entry);
 
   __ bind(&gotta_call_runtime);