Fix secondary stub cache and add a test for the stub cache lookups.

test/cctest/test-api.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 16084 matching lines @@
   CompileRun("throw 'exception';");
 }
 
 
 TEST(CallCompletedCallbackTwoExceptions) {
   v8::HandleScope scope;
   LocalContext env;
   v8::V8::AddCallCompletedCallback(CallCompletedCallbackException);
   CompileRun("throw 'first exception';");
 }
+
+
+static int probes_counter = 0;
+static int misses_counter = 0;
+static int updates_counter = 0;
+
+
+static int* LookupCounter(const char* name) {

[Sven Panne, 2012/02/29 09:37:42]

It seems that all those statics here are only used in DEBUG mode, so I guess
that gcc will complain in release mode.

[Erik Corry, 2012/02/29 10:45:59]

It does not complain about probes_counter etc. but it does complain about
kMegaMorphicTestProgram.  Go figure.

+  if (strcmp(name, "c:V8.MegamorphicStubCacheProbes") == 0) {
+    return &probes_counter;
+  } else if (strcmp(name, "c:V8.MegamorphicStubCacheMisses") == 0) {
+    return &misses_counter;
+  } else if (strcmp(name, "c:V8.MegamorphicStubCacheUpdates") == 0) {
+    return &updates_counter;
+  }
+  return NULL;
+}
+
+
+static const char* kMegamorphicTestProgram =
+    "function ClassA() { };"
+    "function ClassB() { };"
+    "ClassA.prototype.foo = function() { };"
+    "ClassB.prototype.foo = function() { };"
+    "function fooify(obj) { obj.foo(); };"
+    "var a = new ClassA();"
+    "var b = new ClassB();"
+    "for (var i = 0; i < 10000; i++) {"
+    "  fooify(a);"
+    "  fooify(b);"
+    "}";
+
+
+TEST(SecondaryStubCache) {

[Sven Panne, 2012/02/29 09:37:42]

This differs from TEST(PrimaryStubCache) only in a single line, so a separate
method for the common code might be appropriate.

Just out of curiosity: Where/how do we set/reset the i::FLAG_foo flags for each
test?

[Erik Corry, 2012/02/29 10:45:59]

Done
 
Each test is run in its own process, which terminates, so no need to reset
anything.  This is why these tests are not THREADED_TEST tests.

+#ifdef DEBUG
+  i::FLAG_native_code_counters = true;
+  i::FLAG_test_secondary_stub_cache = true;
+  i::FLAG_crankshaft = false;
+  V8::SetCounterFunction(LookupCounter);
+  v8::HandleScope scope;
+  LocalContext env;
+  int initial_probes = probes_counter;
+  int initial_misses = misses_counter;
+  int initial_updates = updates_counter;
+  CompileRun(kMegamorphicTestProgram);
+  int probes = probes_counter - initial_probes;
+  int misses = misses_counter - initial_misses;
+  int updates = updates_counter - initial_updates;
+  CHECK_LT(updates, 10);
+  CHECK_LT(misses, 10);
+  CHECK_GE(probes, 10000);
+#endif
+}
+
+
+TEST(PrimaryStubCache) {
+#ifdef DEBUG
+  i::FLAG_native_code_counters = true;
+  i::FLAG_test_primary_stub_cache = true;
+  i::FLAG_crankshaft = false;
+  V8::SetCounterFunction(LookupCounter);
+  v8::HandleScope scope;
+  LocalContext env;
+  int initial_probes = probes_counter;
+  int initial_misses = misses_counter;
+  int initial_updates = updates_counter;
+  CompileRun(kMegamorphicTestProgram);
+  int probes = probes_counter - initial_probes;
+  int misses = misses_counter - initial_misses;
+  int updates = updates_counter - initial_updates;
+  CHECK_LT(updates, 10);
+  CHECK_LT(misses, 10);
+  CHECK_GE(probes, 10000);
+#endif
+}
+