Enable optimization of top-level code.

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 238 matching lines @@
           total_code_generated_ > 0 &&
           total_code_generated_ < 2000) {
         // If no code was generated and no IC was patched since the last tick,
         // but a little code has already been generated since last Reset(),
         // then type info might already be stable and we can optimize now.
         Optimize(function, "stable on startup");
       } else {
         function->shared()->set_profiler_ticks(ticks + 1);
       }
     } else {  // !FLAG_counting_profiler
+      // Only record top-level code on top of the execution stack and

[Jakob Kummerow, 2012/02/14 10:08:26]

It seems this entire addition is independent of the profiler implementation, so
please move it before the if/else block (i.e. before line 235).

[fschneider, 2012/02/14 13:03:11]

Done.

Good point. It should work with both profilers.

+      // avoid optimizing excessively large scripts since top-level code
+      // will be executed only once.
+      const int kMaxToplevelSourceSize = 10 * 1024;
+      if (function->shared()->is_toplevel()
+          && (frame_count > 1
+              || function->shared()->SourceSize() > kMaxToplevelSourceSize)) {
+        continue;
+      }
+
       samples[sample_count++] = function;
 
       int function_size = function->shared()->SourceSize();
       int threshold_size_factor = (function_size > kSizeLimit)
           ? sampler_threshold_size_factor_
           : 1;
 
       int threshold = sampler_threshold_ * threshold_size_factor;
 
       if (LookupSample(function) >= threshold) {
@@ skipping 136 matching lines @@
 
 bool RuntimeProfilerRateLimiter::SuspendIfNecessary() {
   if (!RuntimeProfiler::IsSomeIsolateInJS()) {
     return RuntimeProfiler::WaitForSomeIsolateToEnterJS();
   }
   return false;
 }
 
 
 } }  // namespace v8::internal