[turbofan] Implement OSR for outer loops.

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 0337c813b9e08d4f6ccb5898ef1104934b2579ba..92c8712347f3e410ca341ee145d3928cbd36b7ed 100644
--- a/src/compiler/ast-graph-builder.h
+++ b/src/compiler/ast-graph-builder.h
@@ -114,7 +114,10 @@ class AstGraphBuilder : public StructuredGraphBuilder, public AstVisitor {
   // Builder for stack-check guards.
   Node* BuildStackCheck();
 
+  bool IsOsrLoopEntry(IterationStatement* stmt);
+
 #define DECLARE_VISIT(type) void Visit##type(type* node) OVERRIDE;
+
   // Visiting functions for AST nodes make this an AstVisitor.
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
@@ -140,6 +143,9 @@ class AstGraphBuilder : public StructuredGraphBuilder, public AstVisitor {
   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_;