MapCache simplification. It is now a FixedArray that maps number of properties to a WeakCell with...

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 21193 matching lines @@
   obj->Set(v8_num(2), v8_str("foobar"));
   CHECK_EQ(v8_str("DONT_CHANGE"), obj->Get(v8_num(2)));
 
   // Test non-smi case.
   obj->ForceSet(v8_str("2000000000"), v8_str("DONT_CHANGE"), v8::ReadOnly);
   obj->Set(v8_str("2000000000"), v8_str("foobar"));
   CHECK_EQ(v8_str("DONT_CHANGE"), obj->Get(v8_str("2000000000")));
 }
 
 
+static int CountLiveMapsInMapCache(i::Context* context) {
+  i::FixedArray* map_cache = i::FixedArray::cast(context->map_cache());
+  int length = map_cache->length();
+  int count = 0;
+  for (int i = 0; i < length; i++) {
+    i::Object* value = map_cache->get(i);
+    if (value->IsWeakCell() && !i::WeakCell::cast(value)->cleared()) count++;
+  }
+  return count;
+}
+
+
 THREADED_TEST(Regress1516) {
   LocalContext context;
   v8::HandleScope scope(context->GetIsolate());
 
+  // Object with 20 properties is not a common case, so it should be removed
+  // from the cache after GC.
   { v8::HandleScope temp_scope(context->GetIsolate());
-    CompileRun("({'a': 0})");
+    CompileRun(
+        "({"
+        "'a00': 0, 'a01': 0, 'a02': 0, 'a03': 0, 'a04': 0, "
+        "'a05': 0, 'a06': 0, 'a07': 0, 'a08': 0, 'a09': 0, "
+        "'a10': 0, 'a11': 0, 'a12': 0, 'a13': 0, 'a14': 0, "
+        "'a15': 0, 'a16': 0, 'a17': 0, 'a18': 0, 'a19': 0, "
+        "})");
   }
 
-  int elements;
-  { i::MapCache* map_cache =
-        i::MapCache::cast(CcTest::i_isolate()->context()->map_cache());
-    elements = map_cache->NumberOfElements();
-    CHECK_LE(1, elements);
-  }
+  int elements = CountLiveMapsInMapCache(CcTest::i_isolate()->context());
+  CHECK_LE(1, elements);
 
-  CcTest::heap()->CollectAllGarbage(
-      i::Heap::kAbortIncrementalMarkingMask);
-  { i::Object* raw_map_cache = CcTest::i_isolate()->context()->map_cache();
-    if (raw_map_cache != CcTest::heap()->undefined_value()) {
-      i::MapCache* map_cache = i::MapCache::cast(raw_map_cache);
-      CHECK_GT(elements, map_cache->NumberOfElements());
-    }
-  }
+  CcTest::heap()->CollectAllGarbage(i::Heap::kAbortIncrementalMarkingMask);
+
+  CHECK_GT(elements, CountLiveMapsInMapCache(CcTest::i_isolate()->context()));
 }
 
 
 static bool BlockProtoNamedSecurityTestCallback(Local<v8::Object> global,
                                                 Local<Value> name,
                                                 v8::AccessType type,
                                                 Local<Value> data) {
   // Only block read access to __proto__.
   if (type == v8::ACCESS_GET &&
       name->IsString() &&
@@ skipping 2937 matching lines @@
   char chunk2[] =
       "XX\xec\x92\x81r = 13;\n"
       "  return foob\xec\x92\x81\xec\x92\x81r;\n"
       "}\n";
   chunk1[strlen(chunk1) - 1] = reference[0];
   chunk2[0] = reference[1];
   chunk2[1] = reference[2];
   const char* chunks[] = {chunk1, chunk2, "foo();", NULL};
   RunStreamingTest(chunks, v8::ScriptCompiler::StreamedSource::UTF8);
 }