Initial support for count-based profiling

src/execution.cc

Index: src/execution.cc
diff --git a/src/execution.cc b/src/execution.cc
index 71e8ea34a1eb72b2050086889d812afa666c68cd..56d102f9a9f5b95c9a1ff5e5b57a2531c6679139 100644
--- a/src/execution.cc
+++ b/src/execution.cc
@@ -1,4 +1,4 @@
-// Copyright 2011 the V8 project authors. All rights reserved.
+// 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:
@@ -49,6 +49,7 @@ StackGuard::StackGuard()
 
 
 void StackGuard::set_interrupt_limits(const ExecutionAccess& lock) {
+  if (FLAG_count_based_interrupts) return;
   ASSERT(isolate_ != NULL);
   // Ignore attempts to interrupt when interrupts are postponed.
   if (should_postpone_interrupts(lock)) return;
@@ -59,6 +60,7 @@ void StackGuard::set_interrupt_limits(const ExecutionAccess& lock) {
 
 
 void StackGuard::reset_limits(const ExecutionAccess& lock) {
+  if (FLAG_count_based_interrupts) return;
   ASSERT(isolate_ != NULL);
   thread_local_.jslimit_ = thread_local_.real_jslimit_;
   thread_local_.climit_ = thread_local_.real_climit_;
@@ -882,7 +884,9 @@ MaybeObject* Execution::HandleStackGuardInterrupt() {
   }
 
   isolate->counters()->stack_interrupts()->Increment();
-  if (stack_guard->IsRuntimeProfilerTick()) {
+  // If FLAG_count_based_interrupts, every interrupt is a profiler interrupt.
+  if (FLAG_count_based_interrupts ||
+      stack_guard->IsRuntimeProfilerTick()) {
     isolate->counters()->runtime_profiler_ticks()->Increment();
     stack_guard->Continue(RUNTIME_PROFILER_TICK);
     isolate->runtime_profiler()->OptimizeNow();
@@ -904,4 +908,5 @@ MaybeObject* Execution::HandleStackGuardInterrupt() {
   return isolate->heap()->undefined_value();
 }
 
+
 } }  // namespace v8::internal