Reland "[heap] Add page evacuation mode for new->new"

test/cctest/heap/test-page-promotion.cc

+// Copyright 2016 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/heap/array-buffer-tracker.h"
+#include "test/cctest/cctest.h"
+#include "test/cctest/heap/heap-utils.h"
+
+namespace {
+
+v8::Isolate* NewIsolateForPagePromotion() {
+  i::FLAG_page_promotion = true;
+  i::FLAG_page_promotion_threshold = 0;  // %
+  i::FLAG_min_semi_space_size = 8 * (i::Page::kPageSize / i::MB);
+  // We cannot optimize for size as we require a new space with more than one
+  // page.
+  i::FLAG_optimize_for_size = false;
+  // Set max_semi_space_size because it could've been initialized by an
+  // implication of optimize_for_size.
+  i::FLAG_max_semi_space_size = i::FLAG_min_semi_space_size;
+  v8::Isolate::CreateParams create_params;
+  create_params.array_buffer_allocator = CcTest::array_buffer_allocator();
+  v8::Isolate* isolate = v8::Isolate::New(create_params);
+  return isolate;
+}
+
+}  // namespace
+
+namespace v8 {
+namespace internal {
+
+UNINITIALIZED_TEST(PagePromotion_NewToOld) {
+  v8::Isolate* isolate = NewIsolateForPagePromotion();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  {
+    v8::Isolate::Scope isolate_scope(isolate);
+    v8::HandleScope handle_scope(isolate);
+    v8::Context::New(isolate)->Enter();
+    Heap* heap = i_isolate->heap();
+
+    std::vector<Handle<FixedArray>> handles;
+    heap::SimulateFullSpace(heap->new_space(), &handles);
+    heap->CollectGarbage(NEW_SPACE);
+    CHECK_GT(handles.size(), 0u);
+    // First object in handle should be on the first page.
+    Handle<FixedArray> first_object = handles.front();
+    Page* first_page = Page::FromAddress(first_object->address());
+    // To perform a sanity check on live bytes we need to mark the heap.
+    heap::SimulateIncrementalMarking(heap, true);
+    // Sanity check that the page meets the requirements for promotion.
+    const int threshold_bytes =
+        FLAG_page_promotion_threshold * Page::kAllocatableMemory / 100;
+    CHECK_GE(first_page->LiveBytes(), threshold_bytes);
+
+    // Actual checks: The page is in new space first, but is moved to old space
+    // during a full GC.
+    CHECK(heap->new_space()->ContainsSlow(first_page->address()));
+    CHECK(!heap->old_space()->ContainsSlow(first_page->address()));
+    heap::GcAndSweep(heap, OLD_SPACE);
+    CHECK(!heap->new_space()->ContainsSlow(first_page->address()));
+    CHECK(heap->old_space()->ContainsSlow(first_page->address()));
+  }
+}
+
+UNINITIALIZED_TEST(PagePromotion_NewToNew) {
+  v8::Isolate* isolate = NewIsolateForPagePromotion();
+  Isolate* i_isolate = reinterpret_cast<Isolate*>(isolate);
+  {
+    v8::Isolate::Scope isolate_scope(isolate);
+    v8::HandleScope handle_scope(isolate);
+    v8::Context::New(isolate)->Enter();
+    Heap* heap = i_isolate->heap();
+
+    std::vector<Handle<FixedArray>> handles;
+    heap::SimulateFullSpace(heap->new_space(), &handles);
+    CHECK_GT(handles.size(), 0u);
+    // Last object in handles should definitely be on the last page which does
+    // not contain the age mark.
+    Handle<FixedArray> last_object = handles.back();
+    Page* to_be_promoted_page = Page::FromAddress(last_object->address());
+    CHECK(to_be_promoted_page->Contains(last_object->address()));
+    CHECK(heap->new_space()->ToSpaceContainsSlow(last_object->address()));
+    heap::GcAndSweep(heap, OLD_SPACE);
+    CHECK(heap->new_space()->ToSpaceContainsSlow(last_object->address()));
+    CHECK(to_be_promoted_page->Contains(last_object->address()));
+  }
+}
+
+UNINITIALIZED_TEST(PagePromotion_NewToNewJSArrayBuffer) {
+  // Test makes sure JSArrayBuffer backing stores are still tracked after
+  // new-to-new promotion.
+  v8::Isolate* isolate = NewIsolateForPagePromotion();
+  Isolate* i_isolate = reinterpret_cast<Isolate*>(isolate);
+  {
+    v8::Isolate::Scope isolate_scope(isolate);
+    v8::HandleScope handle_scope(isolate);
+    v8::Context::New(isolate)->Enter();
+    Heap* heap = i_isolate->heap();
+
+    // Fill the current page which potentially contains the age mark.
+    heap::FillCurrentPage(heap->new_space());
+
+    // Allocate a buffer we would like to check against.
+    Handle<JSArrayBuffer> buffer =
+        i_isolate->factory()->NewJSArrayBuffer(SharedFlag::kNotShared);
+    JSArrayBuffer::SetupAllocatingData(buffer, i_isolate, 100);
+    std::vector<Handle<FixedArray>> handles;
+    // Simulate a full space, filling the interesting page with live objects.
+    heap::SimulateFullSpace(heap->new_space(), &handles);
+    CHECK_GT(handles.size(), 0u);
+    // Last object in handles should definitely be on the last page which does
+    // not contain the age mark.
+    Handle<FixedArray> first_object = handles.front();
+    Page* to_be_promoted_page = Page::FromAddress(first_object->address());
+    CHECK(to_be_promoted_page->Contains(first_object->address()));
+    CHECK(to_be_promoted_page->Contains(buffer->address()));
+    CHECK(heap->new_space()->ToSpaceContainsSlow(first_object->address()));
+    CHECK(heap->new_space()->ToSpaceContainsSlow(buffer->address()));
+    heap::GcAndSweep(heap, OLD_SPACE);
+    CHECK(heap->new_space()->ToSpaceContainsSlow(first_object->address()));
+    CHECK(heap->new_space()->ToSpaceContainsSlow(buffer->address()));
+    CHECK(to_be_promoted_page->Contains(first_object->address()));
+    CHECK(to_be_promoted_page->Contains(buffer->address()));
+    CHECK(ArrayBufferTracker::IsTracked(*buffer));
+  }
+}
+
+}  // namespace internal
+}  // namespace v8