[turbofan] Implement OSR for outer loops.

src/compiler/ast-graph-builder.h

 // Copyright 2014 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_COMPILER_AST_GRAPH_BUILDER_H_
 #define V8_COMPILER_AST_GRAPH_BUILDER_H_
 
 #include "src/v8.h"
 
 #include "src/ast.h"
@@ skipping 96 matching lines @@
   Node* BuildHoleCheckSilent(Node* value, Node* for_hole, Node* not_hole);
   Node* BuildHoleCheckThrow(Node* value, Variable* var, Node* not_hole,
                             BailoutId bailout_id);
 
   // Builders for binary operations.
   Node* BuildBinaryOp(Node* left, Node* right, Token::Value op);
 
   // Builder for stack-check guards.
   Node* BuildStackCheck();
 
+  bool IsOsrLoopEntry(IterationStatement* stmt);
+
 #define DECLARE_VISIT(type) virtual void Visit##type(type* node) OVERRIDE;
   // Visiting functions for AST nodes make this an AstVisitor.
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
   // Visiting function for declarations list is overridden.
   void VisitDeclarations(ZoneList<Declaration*>* declarations) OVERRIDE;
 
  private:
   CompilationInfo* info_;
   AstContext* ast_context_;
   JSGraph* jsgraph_;
 
   // List of global declarations for functions and variables.
   ZoneVector<Handle<Object>> globals_;
 
   // Stack of breakable statements entered by the visitor.
   BreakableScope* breakable_;
 
   // Stack of context objects pushed onto the chain by the visitor.
   ContextScope* execution_context_;
 
   // Nodes representing values in the activation record.
   SetOncePointer<Node> function_closure_;
   SetOncePointer<Node> function_context_;
 
+  // The node representing the OSR entry into the loop, if any.
+  SetOncePointer<Node> osr_loop_entry_;
+
   // Result of loop assignment analysis performed before graph creation.
   LoopAssignmentAnalysis* loop_assignment_analysis_;
 
   CompilationInfo* info() const { return info_; }
   inline StrictMode strict_mode() const;
   JSGraph* jsgraph() { return jsgraph_; }
   JSOperatorBuilder* javascript() { return jsgraph_->javascript(); }
   ZoneVector<Handle<Object>>* globals() { return &globals_; }
 
   // Current scope during visitation.
@@ skipping 289 matching lines @@
 
 Scope* AstGraphBuilder::current_scope() const {
   return execution_context_->scope();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_AST_GRAPH_BUILDER_H_