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

runtime/vm/assembler_ia32.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_IA32)
 
 #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 code and disassembly");
 
 
 class DirectCallRelocation : public AssemblerFixup {
  public:
   void Process(const MemoryRegion& region, int position) {
     // Direct calls are relative to the following instruction on x86.
     int32_t pointer = region.Load<int32_t>(position);
     int32_t delta = region.start() + position + sizeof(int32_t);
     region.Store<int32_t>(position, pointer - delta);
   }
@@ skipping 1525 matching lines @@
 
 void Assembler::EmitGenericShift(int rm,
                                  Register operand,
                                  Register shifter) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   ASSERT(shifter == ECX);
   EmitUint8(0xD3);
   EmitOperand(rm, Operand(operand));
 }
 
+
+void Assembler::Comment(const char* comment) {
+  if (FLAG_code_comments) {
+    comments_.Add(new CodeComment(buffer_.GetPosition(),
+                                  String::Handle(String::New(comment))));
+  }
+}
+
+
+const Code::Comments& Assembler::GetCodeComments() const {
+  Code::Comments& comments = Code::Comments::New(comments_.length());
+
+  for (intptr_t i = 0; i < comments_.length(); i++) {
+    comments.SetPCOffsetAt(i, comments_[i]->pc_offset());
+    comments.SetCommentAt(i, comments_[i]->comment());
+  }
+
+  return comments;
+}
+
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32