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

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 86bd0b75b5a41a80af1696a8b22783424d70eb19..5b528ce22574bf81c1110d663a6259e50fa304ab 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -6072,11 +6072,65 @@ const char* ExceptionHandlers::ToCString() const {
 }
 
 
+CodeComments CodeComments::New(int count) {
+  if (count == 0) return CodeComments();
+  return CodeComments(Array::New(count * kNumberOfEntries));
+}
+
+
+intptr_t CodeComments::Length() {
+  return comments_.IsNull() ? 0 : (comments_.Length() / kNumberOfEntries);
+}
+
+
+intptr_t CodeComments::PCAt(int idx)  {
+  return Smi::CheckedHandle(
+      comments_.At(idx * kNumberOfEntries + kPCEntry)).Value();
+}
+
+
+void CodeComments::SetPCAt(int idx, intptr_t pc)  {
+  comments_.SetAt(idx * kNumberOfEntries + kPCEntry,
+                  Smi::Handle(Smi::New(pc)));
+}
+
+
+const String& CodeComments::CommentAt(int idx) {
+  return String::CheckedHandle(
+      comments_.At(idx * kNumberOfEntries + kCommentEntry));
+}
+
+
+void CodeComments::SetCommentAt(int idx, const String& comment) {
+  comments_.SetAt(idx * kNumberOfEntries + kCommentEntry, comment);
+}
+
+
+CodeComments::CodeComments(RawArray* comments)
+    : comments_(Array::Handle(comments)) {
+}
+
+
+CodeComments::CodeComments()
+    : comments_(Array::Handle()) {
+}
+
+
 void Code::set_stackmaps(const Array& maps) const {
   StorePointer(&raw_ptr()->stackmaps_, maps.raw());
 }
 
 
+CodeComments Code::comments() const  {
+  return CodeComments(raw_ptr()->comments_);
+}
+
+
+void Code::set_comments(const CodeComments& comments) const {
+  StorePointer(&raw_ptr()->comments_, comments.comments_.raw());
+}
+
+
 RawCode* Code::New(int pointer_offsets_length) {
   const Class& cls = Class::Handle(Object::code_class());
   Code& result = Code::Handle();