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 47 matching lines @@
 
 static const int kSamplerThresholdSizeFactorInit = 3;
 
 static const int kSizeLimit = 1500;
 
 // Constants for counter based profiler.
 
 // Number of times a function has to be seen on the stack before it is
 // optimized.
 static const int kProfilerTicksBeforeOptimization = 2;
+// If a function does not have enough type info (according to
+// FLAG_type_info_threshold), but has seen a huge number of ticks,
+// optimize it as it is.
+static const int kTicksWhenNotEnoughTypeInfo = 100;
+// We only have one byte to store the number of ticks.
+STATIC_ASSERT(kTicksWhenNotEnoughTypeInfo < 256);
 
 // Maximum size in bytes of generated code for a function to be optimized
 // the very first time it is seen on the stack.
 static const int kMaxSizeEarlyOpt = 500;
 
 
 Atomic32 RuntimeProfiler::state_ = 0;
 
 // TODO(isolates): Clean up the semaphore when it is no longer required.
 static LazySemaphore<0>::type semaphore = LAZY_SEMAPHORE_INITIALIZER;
@@ skipping 20 matching lines @@
 void RuntimeProfiler::GlobalSetup() {
   ASSERT(!has_been_globally_set_up_);
   enabled_ = V8::UseCrankshaft() && FLAG_opt;
 #ifdef DEBUG
   has_been_globally_set_up_ = true;
 #endif
 }
 
 
 static void GetICCounts(JSFunction* function,
-                        int* ic_with_typeinfo_count,
+                        int* ic_with_type_info_count,
                         int* ic_total_count,
                         int* percentage) {
   *ic_total_count = 0;
-  *ic_with_typeinfo_count = 0;
+  *ic_with_type_info_count = 0;
   Object* raw_info =
       function->shared()->code()->type_feedback_info();
   if (raw_info->IsTypeFeedbackInfo()) {
     TypeFeedbackInfo* info = TypeFeedbackInfo::cast(raw_info);
-    *ic_with_typeinfo_count = info->ic_with_typeinfo_count();
+    *ic_with_type_info_count = info->ic_with_type_info_count();
     *ic_total_count = info->ic_total_count();
   }
   *percentage = *ic_total_count > 0
-      ? 100 * *ic_with_typeinfo_count / *ic_total_count
+      ? 100 * *ic_with_type_info_count / *ic_total_count
       : 100;
 }
 
 
 void RuntimeProfiler::Optimize(JSFunction* function, const char* reason) {
   ASSERT(function->IsOptimizable());
   if (FLAG_trace_opt) {
     PrintF("[marking ");
     function->PrintName();
     PrintF(" 0x%" V8PRIxPTR, reinterpret_cast<intptr_t>(function->address()));
@@ skipping 122 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) {
-          // If this function does not have enough type info, but has
-          // seen a huge number of ticks, optimize it as it is.
+        } else if (ticks >= kTicksWhenNotEnoughTypeInfo) {
           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