Pretenure call new support.

test/cctest/test-mementos.cc

 // Copyright 2014 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 39 matching lines @@
   AllocationMemento* memento =
       reinterpret_cast<AllocationMemento*>(new_space->top() + kHeapObjectTag);
   memento->set_map_no_write_barrier(heap->allocation_memento_map());
   memento->set_allocation_site(
       reinterpret_cast<AllocationSite*>(kHeapObjectTag), SKIP_WRITE_BARRIER);
 
   // Call GC to see if we can handle a poisonous memento right after the
   // current new space top pointer.
   heap->CollectAllGarbage(Heap::kAbortIncrementalMarkingMask);
 }
+
+
+TEST(PretenuringCallNew) {
+  CcTest::InitializeVM();
+  if (!i::FLAG_allocation_site_pretenuring) return;
+  if (!i::FLAG_pretenuring_call_new) return;
+
+  v8::HandleScope scope(CcTest::isolate());
+  Isolate* isolate = CcTest::i_isolate();
+  Heap* heap = isolate->heap();
+
+  // We need to create several instances to get past the slack-tracking
+  // phase, where mementos aren't emitted.
+  int call_count = 10;
+  CHECK_GE(call_count, SharedFunctionInfo::kGenerousAllocationCount);
+  i::ScopedVector<char> test_buf(1024);
+  const char* program =
+      "function f() {"
+      "  this.a = 3;"
+      "  this.b = {};"
+      "  return this;"
+      "};"
+      "var a;"
+      "for(var i = 0; i < %d; i++) {"
+      "  a = new f();"
+      "}"
+      "a;";

[Hannes Payer (out of office), 2014/02/18 16:24:26]

a == return a; ?

[mvstanton, 2014/02/19 08:40:26]

Done.

+  i::OS::SNPrintF(test_buf, program, call_count);
+  v8::Local<v8::Value> res = CompileRun(test_buf.start());
+  Handle<JSObject> o =
+      v8::Utils::OpenHandle(*v8::Handle<v8::Object>::Cast(res));
+
+  // The object of class f should have a memento secreted behind it.
+  Address memento_address = o->address() + o->map()->instance_size();
+  AllocationMemento* memento =
+      reinterpret_cast<AllocationMemento*>(memento_address + kHeapObjectTag);
+  CHECK_EQ(memento->map(), heap->allocation_memento_map());
+
+  // Furthermore, how many mementos did we create? The count should match
+  // call_count - SharedFunctionInfo::kGenerousAllocationCount.
+  AllocationSite* site = memento->GetAllocationSite();
+  CHECK_EQ(call_count - SharedFunctionInfo::kGenerousAllocationCount,
+           site->pretenure_create_count()->value());
+}