Fix OSR for nested loops.

src/runtime-profiler.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 172 matching lines @@
 
   // We are not prepared to do OSR for a function that already has an
   // allocated arguments object.  The optimized code would bypass it for
   // arguments accesses, which is unsound.  Don't try OSR.
   if (shared->uses_arguments()) return;
 
   // We're using on-stack replacement: patch the unoptimized code so that
   // any back edge in any unoptimized frame will trigger on-stack
   // replacement for that frame.
   if (FLAG_trace_osr) {
-    PrintF("[patching stack checks in ");
+    PrintF("[patching back edges in ");
     function->PrintName();
     PrintF(" for on-stack replacement]\n");
   }
 
-  // Get the stack check stub code object to match against.  We aren't
+  // Get the interrupt stub code object to match against.  We aren't
   // prepared to generate it, but we don't expect to have to.
-  Code* stack_check_code = NULL;
+  Code* interrupt_code = NULL;
   InterruptStub interrupt_stub;
-  bool found_code = interrupt_stub.FindCodeInCache(&stack_check_code, isolate_);
+  bool found_code = interrupt_stub.FindCodeInCache(&interrupt_code, isolate_);
   if (found_code) {
     Code* replacement_code =
         isolate_->builtins()->builtin(Builtins::kOnStackReplacement);
     Code* unoptimized_code = shared->code();
-    Deoptimizer::PatchStackCheckCode(unoptimized_code,
-                                     stack_check_code,
-                                     replacement_code);
+    Deoptimizer::PatchInterruptCode(
+        unoptimized_code, interrupt_code, replacement_code);
   }
 }
 
 
 void RuntimeProfiler::ClearSampleBuffer() {
   memset(sampler_window_, 0, sizeof(sampler_window_));
   memset(sampler_window_weight_, 0, sizeof(sampler_window_weight_));
 }
 
 
@@ skipping 69 matching lines @@
     if (shared_code->kind() != Code::FUNCTION) continue;
     if (function->IsInRecompileQueue()) continue;
 
     // Attempt OSR if we are still running unoptimized code even though the
     // the function has long been marked or even already been optimized.
     if (!frame->is_optimized() &&
         (function->IsMarkedForLazyRecompilation() ||
          function->IsMarkedForParallelRecompilation() ||
          function->IsOptimized())) {
       int nesting = shared_code->allow_osr_at_loop_nesting_level();
-      if (nesting == 0) AttemptOnStackReplacement(function);
-      int new_nesting = Min(nesting + 1, Code::kMaxLoopNestingMarker);
-      shared_code->set_allow_osr_at_loop_nesting_level(new_nesting);
+      if (nesting < Code::kMaxLoopNestingMarker) {
+        int new_nesting = nesting + 1;
+        shared_code->set_allow_osr_at_loop_nesting_level(new_nesting);
+        AttemptOnStackReplacement(function);
+      }
     }
 
     // Only record top-level code on top of the execution stack and
     // avoid optimizing excessively large scripts since top-level code
     // will be executed only once.
     const int kMaxToplevelSourceSize = 10 * 1024;
     if (shared->is_toplevel() &&
         (frame_count > 1 || shared->SourceSize() > kMaxToplevelSourceSize)) {
       continue;
     }
@@ skipping 170 matching lines @@
 
 
 void RuntimeProfiler::UpdateSamplesAfterCompact(ObjectVisitor* visitor) {
   for (int i = 0; i < kSamplerWindowSize; i++) {
     visitor->VisitPointer(&sampler_window_[i]);
   }
 }
 
 
 } }  // namespace v8::internal