Introduce concurrent on-stack replacement.

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index bdb168fe0d107a397a724bded304902be20a8774..e8e1fc5743a5570ff9a692f62c6004569780cb9b 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -496,11 +496,13 @@ class LChunk;
 // using last_status().
 class OptimizingCompiler: public ZoneObject {
  public:
-  explicit OptimizingCompiler(CompilationInfo* info)
+  explicit OptimizingCompiler(CompilationInfo* info,
+                              uint32_t osr_pc_offset = 0)
       : info_(info),
         graph_builder_(NULL),
         graph_(NULL),
         chunk_(NULL),
+        osr_pc_offset_(osr_pc_offset),

[titzer, 2013/09/02 17:03:35]

This is the PC offset of the backedge. It seems weird that it's going be part of
the compiler. Seems like it would fit better in the CompilationInfo.

[Yang, 2013/09/03 08:50:10]

Done.

         last_status_(FAILED) { }
 
   enum Status {
@@ -514,6 +516,7 @@ class OptimizingCompiler: public ZoneObject {
   Status last_status() const { return last_status_; }
   CompilationInfo* info() const { return info_; }
   Isolate* isolate() const { return info()->isolate(); }
+  uint32_t osr_pc_offset() { return osr_pc_offset_; }
 
   MUST_USE_RESULT Status AbortOptimization() {
     info_->AbortOptimization();
@@ -529,6 +532,7 @@ class OptimizingCompiler: public ZoneObject {
   TimeDelta time_taken_to_create_graph_;
   TimeDelta time_taken_to_optimize_;
   TimeDelta time_taken_to_codegen_;
+  uint32_t osr_pc_offset_;
   Status last_status_;
 
   MUST_USE_RESULT Status SetLastStatus(Status status) {
@@ -600,7 +604,8 @@ class Compiler : public AllStatic {
   // success and false if the compilation resulted in a stack overflow.
   static bool CompileLazy(CompilationInfo* info);
 
-  static void RecompileConcurrent(Handle<JSFunction> function);
+  static void RecompileConcurrent(Handle<JSFunction> function,
+                                  uint32_t osr_pc_offset = 0);
 
   // Compile a shared function info object (the function is possibly lazily
   // compiled).
@@ -615,6 +620,12 @@ class Compiler : public AllStatic {
 
   static void InstallOptimizedCode(OptimizingCompiler* info);
 
+  static bool CompileForOnStackReplacement(Handle<JSFunction> function,
+                                           BailoutId* ast_id_out);
+
+  static bool CompileForConcurrentOSR(Handle<JSFunction> function,
+                                      BailoutId* ast_id_out);
+
 #ifdef ENABLE_DEBUGGER_SUPPORT
   static bool MakeCodeForLiveEdit(CompilationInfo* info);
 #endif