[turbofan] Keep AstGraphBuilder context chain length in sync.

src/compiler/ast-graph-builder.h

Index: src/compiler/ast-graph-builder.h
diff --git a/src/compiler/ast-graph-builder.h b/src/compiler/ast-graph-builder.h
index f851a3003665bb85f1f1e343e664352dbcb415d3..b7ed350e569f10b05ad93e24058695b821b1ca52 100644
--- a/src/compiler/ast-graph-builder.h
+++ b/src/compiler/ast-graph-builder.h
@@ -384,6 +384,7 @@ class AstGraphBuilder::Environment : public ZoneObject {
 
   int parameters_count() const { return parameters_count_; }
   int locals_count() const { return locals_count_; }
+  int context_chain_length() { return static_cast<int>(contexts_.size()); }
   int stack_height() {
     return static_cast<int>(values()->size()) - parameters_count_ -
            locals_count_;
@@ -394,9 +395,11 @@ class AstGraphBuilder::Environment : public ZoneObject {
   Node* Lookup(Variable* variable);
   void MarkAllLocalsLive();
 
+  // Operations on the context chain.
   Node* Context() const { return contexts_.back(); }
   void PushContext(Node* context) { contexts()->push_back(context); }
   void PopContext() { contexts()->pop_back(); }
+  void TrimContext(int trim_to_length) { contexts()->resize(trim_to_length); }

[titzer, 2015/04/02 11:03:28]

TrimContextChain?

[Michael Starzinger, 2015/04/02 11:29:20]

Done.

 
   // Operations on the operand stack.
   void Push(Node* node) {
@@ -478,8 +481,6 @@ class AstGraphBuilder::Environment : public ZoneObject {
     return CopyAndShareLiveness();
   }
 
-  int ContextStackDepth() { return static_cast<int>(contexts_.size()); }
-
  private:
   AstGraphBuilder* builder_;
   int parameters_count_;