Initial support for count-based profiling

src/runtime.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 8693 matching lines @@
       succeeded = false;
     }
   }
 
   // Revert to the original stack checks in the original unoptimized code.
   if (FLAG_trace_osr) {
     PrintF("[restoring original stack checks in ");
     function->PrintName();
     PrintF("]\n");
   }
-  StackCheckStub check_stub;
-  Handle<Code> check_code = check_stub.GetCode();
+  Handle<Code> check_code;
+  if (FLAG_count_based_interrupts) {
+    InterruptStub interrupt_stub;
+    check_code = interrupt_stub.GetCode();
+  } else {
+    StackCheckStub check_stub;
+    check_code = check_stub.GetCode();
+  }
   Handle<Code> replacement_code = isolate->builtins()->OnStackReplacement();
   Deoptimizer::RevertStackCheckCode(*unoptimized,
                                     *check_code,
                                     *replacement_code);
 
   // Allow OSR only at nesting level zero again.
   unoptimized->set_allow_osr_at_loop_nesting_level(0);
 
   // If the optimization attempt succeeded, return the AST id tagged as a
   // smi. This tells the builtin that we need to translate the unoptimized
@@ skipping 533 matching lines @@
   // First check if this is a real stack overflow.
   if (isolate->stack_guard()->IsStackOverflow()) {
     NoHandleAllocation na;
     return isolate->StackOverflow();
   }
 
   return Execution::HandleStackGuardInterrupt();
 }
 
 
+RUNTIME_FUNCTION(MaybeObject*, Runtime_Interrupt) {
+  ASSERT(args.length() == 0);
+  return Execution::HandleStackGuardInterrupt();
+}
+
+
 static int StackSize() {
   int n = 0;
   for (JavaScriptFrameIterator it; !it.done(); it.Advance()) n++;
   return n;
 }
 
 
 static void PrintTransition(Object* result) {
   // indentation
   { const int nmax = 80;
@@ skipping 4378 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal