[Interpreter] Save bytecode offset in interpreter stack frames.

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 1a6ee7cda1e836d9b9a5fe465f9edb43080bd339..39dceeef521371046574ddc9c80e3f0ca1038852 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -593,6 +593,10 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   __ Push(rdi);  // Callee's JS function.
   __ Push(rdx);  // Callee's new target.
 
+  // Push zero for bytecode array offset.
+  __ movp(rax, Immediate(0));
+  __ Push(rax);
+
   // Get the bytecode array from the function object and load the pointer to the
   // first entry into edi (InterpreterBytecodeRegister).
   __ movp(rax, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset));
@@ -623,10 +627,10 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
     __ bind(&ok);
 
     // If ok, push undefined as the initial value for all register file entries.
+    // (plus one for the accumulator save slot).
     Label loop_header;
     Label loop_check;
     __ LoadRoot(rdx, Heap::kUndefinedValueRootIndex);
-    __ j(always, &loop_check);
     __ bind(&loop_header);
     // TODO(rmcilroy): Consider doing more than one push per loop iteration.
     __ Push(rdx);
@@ -658,9 +662,8 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   // registers.
   __ LoadRoot(kInterpreterAccumulatorRegister, Heap::kUndefinedValueRootIndex);
   __ movp(kInterpreterRegisterFileRegister, rbp);
-  __ subp(kInterpreterRegisterFileRegister,
-          Immediate(2 * kPointerSize +
-                    StandardFrameConstants::kFixedFrameSizeFromFp));
+  __ addp(kInterpreterRegisterFileRegister,
+          Immediate(InterpreterFrameConstants::kRegisterFilePointerFromFp));
   __ movp(kInterpreterBytecodeOffsetRegister,
           Immediate(BytecodeArray::kHeaderSize - kHeapObjectTag));
   __ LoadRoot(kInterpreterDispatchTableRegister,