Move profiler_ticks to Code object, don't walk the stack when patching ICs

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 243 matching lines @@
           // modify and reset the ticks until next adjustment.
           if (sampler_threshold_ > kSamplerThresholdMin) {
             sampler_threshold_ -= kSamplerThresholdDelta;
             sampler_ticks_until_threshold_adjustment_ =
                 kSamplerTicksBetweenThresholdAdjustment;
           }
         }
       }
     }
 
-    if (function->IsMarkedForLazyRecompilation() &&
-        function->shared()->code()->kind() == Code::FUNCTION) {
-      Code* unoptimized = function->shared()->code();
-      int nesting = unoptimized->allow_osr_at_loop_nesting_level();
+    Code* shared_code = function->shared()->code();
+    if (shared_code->kind() != Code::FUNCTION) continue;
+
+    if (function->IsMarkedForLazyRecompilation()) {
+      int nesting = shared_code->allow_osr_at_loop_nesting_level();
       if (nesting == 0) AttemptOnStackReplacement(function);
       int new_nesting = Min(nesting + 1, Code::kMaxLoopNestingMarker);
-      unoptimized->set_allow_osr_at_loop_nesting_level(new_nesting);
+      shared_code->set_allow_osr_at_loop_nesting_level(new_nesting);
     }
 
     // Do not record non-optimizable functions.
     if (!function->IsOptimizable()) continue;
     if (function->shared()->optimization_disabled()) continue;
 
     // 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 (function->shared()->is_toplevel()
         && (frame_count > 1
             || function->shared()->SourceSize() > kMaxToplevelSourceSize)) {
       continue;
     }
 
     if (FLAG_watch_ic_patching) {
-      int ticks = function->shared()->profiler_ticks();
+      int ticks = shared_code->profiler_ticks();
 
       if (ticks >= kProfilerTicksBeforeOptimization) {
         int typeinfo, total, percentage;
         GetICCounts(function, &typeinfo, &total, &percentage);
         if (percentage >= FLAG_type_info_threshold) {
           // If this particular function hasn't had any ICs patched for enough
           // ticks, optimize it now.
           Optimize(function, "hot and stable");
         } else if (ticks >= 100) {

[ulan, 2012/03/27 11:40:58]

I think 100 should be a named constant with a static assert that the constant <
256.

[Jakob Kummerow, 2012/03/27 12:19:10]

Done.

           // If this function does not have enough type info, but has
           // seen a huge number of ticks, optimize it as it is.
           Optimize(function, "not much type info but very hot");
         } else {
-          function->shared()->set_profiler_ticks(ticks + 1);
+          shared_code->set_profiler_ticks(ticks + 1);
           if (FLAG_trace_opt_verbose) {
             PrintF("[not yet optimizing ");
             function->PrintName();
             PrintF(", not enough type info: %d/%d (%d%%)]\n",
                    typeinfo, total, percentage);
           }
         }
       } else if (!any_ic_changed_ &&
-          function->shared()->code()->instruction_size() < kMaxSizeEarlyOpt) {
+          shared_code->instruction_size() < kMaxSizeEarlyOpt) {
         // If no IC was patched since the last tick and this function is very
         // small, optimistically optimize it now.
         Optimize(function, "small function");
       } else if (!code_generated_ &&
           !any_ic_changed_ &&
           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);
+        shared_code->set_profiler_ticks(ticks + 1);
       }
     } else {  // !FLAG_watch_ic_patching
       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;
@@ skipping 143 matching lines @@
 
 bool RuntimeProfilerRateLimiter::SuspendIfNecessary() {
   if (!RuntimeProfiler::IsSomeIsolateInJS()) {
     return RuntimeProfiler::WaitForSomeIsolateToEnterJS();
   }
   return false;
 }
 
 
 } }  // namespace v8::internal