test/cctest/test-feedback-vector.cc

// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/v8.h"
#include "test/cctest/cctest.h"

#include "src/api.h"
#include "src/debug.h"
#include "src/execution.h"
#include "src/factory.h"
#include "src/global-handles.h"
#include "src/macro-assembler.h"
#include "src/objects.h"

using namespace v8::internal;

namespace {

TEST(VectorStructure) {
  LocalContext context;
  v8::HandleScope scope(context->GetIsolate());
  Isolate* isolate = CcTest::i_isolate();
  Factory* factory = isolate->factory();

  // Empty vectors are the empty fixed array.
  Handle<TypeFeedbackVector> vector = factory->NewTypeFeedbackVector(0, 0);
  CHECK(Handle<FixedArray>::cast(vector)
            .is_identical_to(factory->empty_fixed_array()));
  // Which can nonetheless be queried.
  CHECK_EQ(0, vector->ic_with_type_info_count());
  CHECK_EQ(0, vector->ic_generic_count());
  CHECK_EQ(0, vector->Slots());
  CHECK_EQ(0, vector->ICSlots());

  vector = factory->NewTypeFeedbackVector(1, 0);
  CHECK_EQ(1, vector->Slots());
  CHECK_EQ(0, vector->ICSlots());

  vector = factory->NewTypeFeedbackVector(0, 1);
  CHECK_EQ(0, vector->Slots());
  CHECK_EQ(1, vector->ICSlots());

  vector = factory->NewTypeFeedbackVector(3, 5);
  CHECK_EQ(3, vector->Slots());
  CHECK_EQ(5, vector->ICSlots());

  int index = vector->GetIndex(FeedbackVectorSlot(0));
  CHECK_EQ(TypeFeedbackVector::kReservedIndexCount, index);
  CHECK(FeedbackVectorSlot(0) == vector->ToSlot(index));

  index = vector->GetIndex(FeedbackVectorICSlot(0));
  CHECK_EQ(index, TypeFeedbackVector::kReservedIndexCount + 3);
  CHECK(FeedbackVectorICSlot(0) == vector->ToICSlot(index));

  CHECK_EQ(TypeFeedbackVector::kReservedIndexCount + 3 + 5, vector->length());
}


TEST(VectorSlotClearing) {
  LocalContext context;
  v8::HandleScope scope(context->GetIsolate());
  Isolate* isolate = CcTest::i_isolate();
  Factory* factory = isolate->factory();

  // We only test clearing FeedbackVectorSlots, not FeedbackVectorICSlots.
  // The reason is that FeedbackVectorICSlots need a full code environment
  // to fully test (See VectorICProfilerStatistics test below).
  Handle<TypeFeedbackVector> vector = factory->NewTypeFeedbackVector(5, 0);

  // Fill with information
  vector->Set(FeedbackVectorSlot(0), Smi::FromInt(1));
  vector->Set(FeedbackVectorSlot(1), *factory->fixed_array_map());
  Handle<AllocationSite> site = factory->NewAllocationSite();
  vector->Set(FeedbackVectorSlot(2), *site);

  vector->ClearSlots(NULL);

  // The feedback vector slots are cleared. AllocationSites are granted
  // an exemption from clearing, as are smis.
  CHECK_EQ(Smi::FromInt(1), vector->Get(FeedbackVectorSlot(0)));
  CHECK_EQ(*TypeFeedbackVector::UninitializedSentinel(isolate),
           vector->Get(FeedbackVectorSlot(1)));
  CHECK(vector->Get(FeedbackVectorSlot(2))->IsAllocationSite());
}


TEST(VectorICProfilerStatistics) {
  if (i::FLAG_always_opt) return;
  CcTest::InitializeVM();
  LocalContext context;
  v8::HandleScope scope(context->GetIsolate());
  Isolate* isolate = CcTest::i_isolate();
  Heap* heap = isolate->heap();

  // Make sure function f has a call that uses a type feedback slot.
  CompileRun(
      "function fun() {};"
      "function f(a) { a(); } f(fun);");
  Handle<JSFunction> f = v8::Utils::OpenHandle(
      *v8::Handle<v8::Function>::Cast(CcTest::global()->Get(v8_str("f"))));
  // There should be one IC.
  Code* code = f->shared()->code();
  TypeFeedbackInfo* feedback_info =
      TypeFeedbackInfo::cast(code->type_feedback_info());
  CHECK_EQ(1, feedback_info->ic_total_count());
  CHECK_EQ(0, feedback_info->ic_with_type_info_count());
  CHECK_EQ(0, feedback_info->ic_generic_count());
  TypeFeedbackVector* feedback_vector = f->shared()->feedback_vector();
  CHECK_EQ(1, feedback_vector->ic_with_type_info_count());
  CHECK_EQ(0, feedback_vector->ic_generic_count());

  // Now send the information generic.
  CompileRun("f(Object);");
  feedback_vector = f->shared()->feedback_vector();
  CHECK_EQ(0, feedback_vector->ic_with_type_info_count());
  CHECK_EQ(1, feedback_vector->ic_generic_count());

  // A collection will make the site uninitialized again.
  heap->CollectAllGarbage(i::Heap::kNoGCFlags);
  feedback_vector = f->shared()->feedback_vector();
  CHECK_EQ(0, feedback_vector->ic_with_type_info_count());
  CHECK_EQ(0, feedback_vector->ic_generic_count());

  // The Array function is special. A call to array remains monomorphic
  // and isn't cleared by gc because an AllocationSite is being held.
  CompileRun("f(Array);");
  feedback_vector = f->shared()->feedback_vector();
  CHECK_EQ(1, feedback_vector->ic_with_type_info_count());
  CHECK_EQ(0, feedback_vector->ic_generic_count());

  CHECK(feedback_vector->Get(FeedbackVectorICSlot(0))->IsAllocationSite());
  heap->CollectAllGarbage(i::Heap::kNoGCFlags);
  feedback_vector = f->shared()->feedback_vector();
  CHECK_EQ(1, feedback_vector->ic_with_type_info_count());
  CHECK_EQ(0, feedback_vector->ic_generic_count());
  CHECK(feedback_vector->Get(FeedbackVectorICSlot(0))->IsAllocationSite());
}
}