Simplify isolates access during stack iteration (WAS: Move SafeStackFrameIterator::active_count_...)

src/frames-inl.h

Index: src/frames-inl.h
diff --git a/src/frames-inl.h b/src/frames-inl.h
index e6eaec0e0ce518591370193e2e5edcf35ee3176b..2962ce75bb2b9a957ef508b49dbdb103dd60f930 100644
--- a/src/frames-inl.h
+++ b/src/frames-inl.h
@@ -89,10 +89,20 @@ inline Address* StackHandler::pc_address() const {
 
 
 inline StackHandler* StackFrame::top_handler() const {
+  ASSERT((tagged_isolate_ptr_ & kIsolateTag) == 0);
   return iterator_->handler();
 }
 
 
+inline Isolate* StackFrame::isolate() const {

[Vitaly Repeshko, 2011/04/04 20:37:08]

I'm not convinced we need this tricky stuff. Usually we only create one frame
object per type and reuse them while a stack iterator is active, and we don't
care that much about the memory usage in the live edit case. Please use an
explicit isolate field.

[mnaganov (inactive), 2011/04/05 08:28:23]

I agree. I was in a premature optimization mood. Split into two fields.

+  if ((tagged_isolate_ptr_ & kIsolateTag) == 0) {
+    return iterator_->isolate();
+  } else {
+    return reinterpret_cast<Isolate*>(tagged_isolate_ptr_ & ~kIsolateTag);
+  }
+}
+
+
 inline Code* StackFrame::GetContainingCode(Isolate* isolate, Address pc) {
   return isolate->pc_to_code_cache()->GetCacheEntry(pc)->code;
 }
@@ -168,6 +178,13 @@ inline Object* JavaScriptFrame::function() const {
 
 
 template<typename Iterator>
+inline JavaScriptFrameIteratorTemp<Iterator>::JavaScriptFrameIteratorTemp(
+    Isolate* isolate)
+    : iterator_(isolate) {
+  if (!done()) Advance();
+}
+
+template<typename Iterator>
 inline JavaScriptFrame* JavaScriptFrameIteratorTemp<Iterator>::frame() const {
   // TODO(1233797): The frame hierarchy needs to change. It's
   // problematic that we can't use the safe-cast operator to cast to
@@ -181,11 +198,9 @@ inline JavaScriptFrame* JavaScriptFrameIteratorTemp<Iterator>::frame() const {
 
 template<typename Iterator>
 JavaScriptFrameIteratorTemp<Iterator>::JavaScriptFrameIteratorTemp(
-    StackFrame::Id id) {
-  while (!done()) {
-    Advance();
-    if (frame()->id() == id) return;
-  }
+    Isolate* isolate, StackFrame::Id id)
+    : iterator_(isolate) {
+  AdvanceToId(id);
 }
 
 
@@ -206,6 +221,15 @@ void JavaScriptFrameIteratorTemp<Iterator>::AdvanceToArgumentsFrame() {
 
 
 template<typename Iterator>
+void JavaScriptFrameIteratorTemp<Iterator>::AdvanceToId(StackFrame::Id id) {
+  while (!done()) {
+    Advance();
+    if (frame()->id() == id) return;
+  }
+}
+
+
+template<typename Iterator>
 void JavaScriptFrameIteratorTemp<Iterator>::Reset() {
   iterator_.Reset();
   if (!done()) Advance();