Add a flag to deoptimize all functions every n garbage collections.

R=mstarzinger@chromium.org

Review URL: https://chromiumcodereview.appspot.com/14091013

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14395 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/flag-definitions.h

@@ -230,6 +230,9 @@ DEFINE_bool(stress_environments, false, "environment for every instruction")
 DEFINE_int(deopt_every_n_times,
            0,
            "deoptimize every n times a deopt point is passed")
+DEFINE_int(deopt_every_n_garbage_collections,
+           0,
+           "deoptimize every n garbage collections")
 DEFINE_bool(trap_on_deopt, false, "put a break point before deoptimizing")
 DEFINE_bool(deoptimize_uncommon_cases, true, "deoptimize uncommon cases")
 DEFINE_bool(polymorphic_inlining, true, "polymorphic inlining")

src/heap.cc

@@ -157,6 +157,7 @@ Heap::Heap()
       ms_count_at_last_idle_notification_(0),
       gc_count_at_last_idle_gc_(0),
       scavenges_since_last_idle_round_(kIdleScavengeThreshold),
+      gcs_since_last_deopt_(0),
 #ifdef VERIFY_HEAP
       no_weak_embedded_maps_verification_scope_depth_(0),
 #endif
@@ -487,6 +488,12 @@ void Heap::GarbageCollectionEpilogue() {
   if (FLAG_gc_verbose) Print();
   if (FLAG_code_stats) ReportCodeStatistics("After GC");
 #endif
+  if (FLAG_deopt_every_n_garbage_collections > 0) {
+    if (++gcs_since_last_deopt_ == FLAG_deopt_every_n_garbage_collections) {
+      Deoptimizer::DeoptimizeAll(isolate());
+      gcs_since_last_deopt_ = 0;
+    }
+  }
 
   isolate_->counters()->alive_after_last_gc()->Set(
       static_cast<int>(SizeOfObjects()));

src/heap.h

@@ -2295,6 +2295,11 @@ class Heap {
   unsigned int gc_count_at_last_idle_gc_;
   int scavenges_since_last_idle_round_;
 
+  // If the --deopt_every_n_garbage_collections flag is set to a positive value,
+  // this variable holds the number of garbage collections since the last
+  // deoptimization triggered by garbage collection.
+  int gcs_since_last_deopt_;
+
 #ifdef VERIFY_HEAP
   int no_weak_embedded_maps_verification_scope_depth_;
 #endif