[interpreter] Add accumulator use description to bytecodes.

src/runtime/runtime-interpreter.cc

 // Copyright 2015 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include <iomanip>
 
 #include "src/arguments.h"
 #include "src/frames-inl.h"
@@ skipping 26 matching lines @@
   }
   DCHECK(bytecode_iterator.current_offset() == offset ||
          ((bytecode_iterator.current_offset() + 1) == offset &&
           bytecode_iterator.current_operand_scale() >
               interpreter::OperandScale::kSingle));
 }
 
 void PrintRegisters(std::ostream& os, bool is_input,
                     interpreter::BytecodeArrayIterator& bytecode_iterator,
                     Handle<Object> accumulator) {
-  static const int kRegFieldWidth = static_cast<int>(strlen("accumulator"));
+  static const char kAccumulator[] = "accumulator";
+  static const int kRegFieldWidth = static_cast<int>(sizeof(kAccumulator) - 1);
   static const char* kInputColourCode = "\033[0;36m";
   static const char* kOutputColourCode = "\033[0;35m";
   static const char* kNormalColourCode = "\033[0;m";
   const char* kArrowDirection = is_input ? " -> " : " <- ";
   if (FLAG_log_colour) {
     os << (is_input ? kInputColourCode : kOutputColourCode);
   }
 
+  interpreter::Bytecode bytecode = bytecode_iterator.current_bytecode();
+
   // Print accumulator.
-  os << "      [ accumulator" << kArrowDirection;
-  accumulator->ShortPrint();
-  os << " ]" << std::endl;
+  if ((is_input && interpreter::Bytecodes::ReadsAccumulator(bytecode)) ||
+      (!is_input && interpreter::Bytecodes::WritesAccumulator(bytecode))) {
+    os << "      [ " << kAccumulator << kArrowDirection;
+    accumulator->ShortPrint();
+    os << " ]" << std::endl;
+  }
 
   // Find the location of the register file.
   JavaScriptFrameIterator frame_iterator(
       bytecode_iterator.bytecode_array()->GetIsolate());
   JavaScriptFrame* frame = frame_iterator.frame();
   Address register_file =
       frame->fp() + InterpreterFrameConstants::kRegisterFilePointerFromFp;
 
   // Print the registers.
-  interpreter::Bytecode bytecode = bytecode_iterator.current_bytecode();
   int operand_count = interpreter::Bytecodes::NumberOfOperands(bytecode);
   for (int operand_index = 0; operand_index < operand_count; operand_index++) {
     interpreter::OperandType operand_type =
         interpreter::Bytecodes::GetOperandType(bytecode, operand_index);
     bool should_print =
         is_input
             ? interpreter::Bytecodes::IsRegisterInputOperandType(operand_type)
             : interpreter::Bytecodes::IsRegisterOutputOperandType(operand_type);
     if (should_print) {
       interpreter::Register first_reg =
@@ skipping 82 matching lines @@
 RUNTIME_FUNCTION(Runtime_InterpreterSetPendingMessage) {
   SealHandleScope shs(isolate);
   DCHECK_EQ(1, args.length());
   CONVERT_ARG_HANDLE_CHECKED(Object, message, 0);
   isolate->thread_local_top()->pending_message_obj_ = *message;
   return isolate->heap()->undefined_value();
 }
 
 }  // namespace internal
 }  // namespace v8