[Interpreter] Make dispatch table point to code entry instead of code objects.

src/x64/builtins-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 665 matching lines @@
           Immediate(BytecodeArray::kHeaderSize - kHeapObjectTag));
   __ Move(
       kInterpreterDispatchTableRegister,
       ExternalReference::interpreter_dispatch_table_address(masm->isolate()));
 
   // Dispatch to the first bytecode handler for the function.
   __ movzxbp(rbx, Operand(kInterpreterBytecodeArrayRegister,
                           kInterpreterBytecodeOffsetRegister, times_1, 0));
   __ movp(rbx, Operand(kInterpreterDispatchTableRegister, rbx,
                        times_pointer_size, 0));
-  // TODO(rmcilroy): Make dispatch table point to code entrys to avoid untagging
-  // and header removal.
-  __ addp(rbx, Immediate(Code::kHeaderSize - kHeapObjectTag));
   __ call(rbx);
 
   // Even though the first bytecode handler was called, we will never return.
   __ Abort(kUnexpectedReturnFromBytecodeHandler);
 
   // Load debug copy of the bytecode array.
   __ bind(&load_debug_bytecode_array);
   Register debug_info = kInterpreterBytecodeArrayRegister;
   __ movp(debug_info, FieldOperand(rax, SharedFunctionInfo::kDebugInfoOffset));
   __ movp(kInterpreterBytecodeArrayRegister,
@@ skipping 141 matching lines @@
       Operand(kInterpreterRegisterFileRegister,
               InterpreterFrameConstants::kBytecodeOffsetFromRegisterPointer));
   __ SmiToInteger32(kInterpreterBytecodeOffsetRegister,
                     kInterpreterBytecodeOffsetRegister);
 
   // Dispatch to the target bytecode.
   __ movzxbp(rbx, Operand(kInterpreterBytecodeArrayRegister,
                           kInterpreterBytecodeOffsetRegister, times_1, 0));
   __ movp(rbx, Operand(kInterpreterDispatchTableRegister, rbx,
                        times_pointer_size, 0));
-  __ addp(rbx, Immediate(Code::kHeaderSize - kHeapObjectTag));
   __ jmp(rbx);
 }
 
 
 static void Generate_InterpreterNotifyDeoptimizedHelper(
     MacroAssembler* masm, Deoptimizer::BailoutType type) {
   // Enter an internal frame.
   {
     FrameScope scope(masm, StackFrame::INTERNAL);
 
@@ skipping 1930 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64