Keep a canonical list of shared function infos.

test/cctest/test-heap.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 5908 matching lines @@
   const char* flag = "--turbo-filter=*";
   FlagList::SetFlagsFromString(flag, StrLength(flag));
   FLAG_always_opt = true;
   FLAG_turbo_try_catch = true;
   FLAG_turbo_try_finally = true;
 
   CompileRun(test);
 }
 
 
+static void CheckEqualSharedFunctionInfos(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  Handle<Object> obj1 = v8::Utils::OpenHandle(*args[0]);
+  Handle<Object> obj2 = v8::Utils::OpenHandle(*args[1]);
+  Handle<JSFunction> fun1 = Handle<JSFunction>::cast(obj1);
+  Handle<JSFunction> fun2 = Handle<JSFunction>::cast(obj2);
+  CHECK(fun1->shared() == fun2->shared());
+}
+
+
+static void RemoveCodeAndGC(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  Isolate* isolate = CcTest::i_isolate();
+  Handle<Object> obj = v8::Utils::OpenHandle(*args[0]);
+  Handle<JSFunction> fun = Handle<JSFunction>::cast(obj);
+  fun->ReplaceCode(*isolate->builtins()->CompileLazy());
+  fun->shared()->ReplaceCode(*isolate->builtins()->CompileLazy());
+  isolate->heap()->CollectAllAvailableGarbage("remove code and gc");
+}
+
+
+TEST(CanonicalSharedFunctionInfo) {
+  CcTest::InitializeVM();
+  v8::Isolate* isolate = CcTest::isolate();
+  v8::HandleScope scope(isolate);
+  v8::Handle<v8::ObjectTemplate> global = v8::ObjectTemplate::New(isolate);
+  global->Set(isolate, "check", v8::FunctionTemplate::New(
+                                    isolate, CheckEqualSharedFunctionInfos));
+  global->Set(isolate, "remove",
+              v8::FunctionTemplate::New(isolate, RemoveCodeAndGC));
+  v8::Local<v8::Context> context = v8::Context::New(isolate, NULL, global);
+  v8::Context::Scope cscope(context);
+  CompileRun(
+      "function f() { return function g() {}; }"
+      "var g1 = f();"
+      "remove(f);"
+      "var g2 = f();"
+      "check(g1, g2);");
+
+  CompileRun(
+      "function f() { return (function() { return function g() {}; })(); }"
+      "var g1 = f();"
+      "remove(f);"
+      "var g2 = f();"
+      "check(g1, g2);");
+}
+
+
 TEST(OldGenerationAllocationThroughput) {
   CcTest::InitializeVM();
   v8::HandleScope scope(CcTest::isolate());
   Isolate* isolate = CcTest::i_isolate();
   Heap* heap = isolate->heap();
   GCTracer* tracer = heap->tracer();
   int time1 = 100;
   size_t counter1 = 1000;
   tracer->SampleAllocation(time1, 0, counter1);
   int time2 = 200;
@@ skipping 24 matching lines @@
   size_t counter2 = 2000;
   tracer->SampleAllocation(time2, counter2, counter2);
   size_t throughput = tracer->AllocationThroughputInBytesPerMillisecond(100);
   CHECK_EQ(2 * (counter2 - counter1) / (time2 - time1), throughput);
   int time3 = 1000;
   size_t counter3 = 30000;
   tracer->SampleAllocation(time3, counter3, counter3);
   throughput = tracer->AllocationThroughputInBytesPerMillisecond(100);
   CHECK_EQ(2 * (counter3 - counter1) / (time3 - time1), throughput);
 }