Extend assembler with ability to produce comments for the generated code.

runtime/vm/assembler_x64.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/heap.h"
 #include "vm/memory_region.h"
 #include "vm/runtime_entry.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, print_stop_message, true, "Print stop message.");
+DEFINE_FLAG(bool, code_comments, false, "Include comments into disassembly");
 
 
 void Assembler::InitializeMemoryWithBreakpoints(uword data, int length) {
   memset(reinterpret_cast<void*>(data), Instr::kBreakPointInstruction, length);
 }
 
 
 void Assembler::call(Register reg) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   Operand operand(reg);
@@ skipping 1482 matching lines @@
   ASSERT(shifter == RCX);
   if (wide) {
     EmitRegisterREX(operand, REX_W);
   } else {
     EmitRegisterREX(operand, REX_NONE);
   }
   EmitUint8(0xD3);
   EmitOperand(rm, Operand(operand));
 }
 
+
+void Assembler::Comment(const char* format, ...) {
+  if (FLAG_code_comments) {
+    char buffer[1024];
+
+    va_list args;
+    va_start(args, format);
+    OS::VSNPrint(buffer, sizeof(buffer), format, args);
+    va_end(args);
+
+    comments_.Add(new CodeComment(buffer_.GetPosition(),
+                                  String::Handle(String::New(buffer))));
+  }
+}
+
+
+CodeComments Assembler::GetComments() {
+  CodeComments comments = CodeComments::New(comments_.length());
+
+  for (int i = 0; i < comments_.length(); i++) {
+    comments.SetPCAt(i, comments_[i]->pc());
+    comments.SetCommentAt(i, comments_[i]->comment());
+  }
+
+  return comments;
+}
+
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64