Allow Crankshaft to tolerate certain do-expressions

src/crankshaft/hydrogen.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_CRANKSHAFT_HYDROGEN_H_
 #define V8_CRANKSHAFT_HYDROGEN_H_
 
 #include "src/accessors.h"
 #include "src/allocation.h"
 #include "src/ast/ast.h"
@@ skipping 866 matching lines @@
 
   HArgumentsElements* arguments_elements() { return arguments_elements_; }
   void set_arguments_elements(HArgumentsElements* arguments_elements) {
     arguments_elements_ = arguments_elements;
   }
 
   bool arguments_pushed() { return arguments_elements() != NULL; }
 
   int inlining_id() const { return inlining_id_; }
 
+  void IncrementInDoExpressionScope() { do_expression_scope_count_++; }
+  void DecrementInDoExpressionScope() { do_expression_scope_count_--; }
+  bool IsInsideDoExpressionScope() { return do_expression_scope_count_ > 0; }
+
  private:
   HOptimizedGraphBuilder* owner_;
 
   CompilationInfo* compilation_info_;
 
   // During function inlining, expression context of the call being
   // inlined. NULL when not inlining.
   AstContext* call_context_;
 
   // The kind of call which is currently being inlined.
@@ skipping 12 matching lines @@
   // When inlining HEnterInlined instruction corresponding to the function
   // entry.
   HEnterInlined* entry_;
 
   HArgumentsObject* arguments_object_;
   HArgumentsElements* arguments_elements_;
 
   int inlining_id_;
   SourcePosition outer_source_position_;
 
+  int do_expression_scope_count_;
+
   FunctionState* outer_;
 };
 
 
 class HIfContinuation final {
  public:
   HIfContinuation()
     : continuation_captured_(false),
       true_branch_(NULL),
       false_branch_(NULL) {}
@@ skipping 2089 matching lines @@
     builder_->graph()->IncrementInNoSideEffectsScope();
   }
   ~NoObservableSideEffectsScope() {
     builder_->graph()->DecrementInNoSideEffectsScope();
   }
 
  private:
   HGraphBuilder* builder_;
 };
 
+class DoExpressionScope final {
+ public:
+  explicit DoExpressionScope(HOptimizedGraphBuilder* builder)
+      : builder_(builder) {
+    builder_->function_state()->IncrementInDoExpressionScope();
+  }
+  ~DoExpressionScope() {
+    builder_->function_state()->DecrementInDoExpressionScope();
+  }
+
+ private:
+  HOptimizedGraphBuilder* builder_;
+};
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CRANKSHAFT_HYDROGEN_H_