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// 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 <map>
#include "src/base/region-allocator.h"
#include "src/execution/isolate.h"
#include "src/heap/heap-inl.h"
#include "src/heap/spaces-inl.h"
#include "src/utils/ostreams.h"
#include "test/unittests/test-utils.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace v8 {
namespace internal {
// This is a v8::PageAllocator implementation that decorates provided page
// allocator object with page tracking functionality.
class TrackingPageAllocator : public ::v8::PageAllocator {
public:
explicit TrackingPageAllocator(v8::PageAllocator* page_allocator)
: page_allocator_(page_allocator),
allocate_page_size_(page_allocator_->AllocatePageSize()),
commit_page_size_(page_allocator_->CommitPageSize()),
region_allocator_(kNullAddress, size_t{0} - commit_page_size_,
commit_page_size_) {
CHECK_NOT_NULL(page_allocator);
CHECK(IsAligned(allocate_page_size_, commit_page_size_));
}
~TrackingPageAllocator() override = default;
size_t AllocatePageSize() override { return allocate_page_size_; }
size_t CommitPageSize() override { return commit_page_size_; }
void SetRandomMmapSeed(int64_t seed) override {
return page_allocator_->SetRandomMmapSeed(seed);
}
void* GetRandomMmapAddr() override {
return page_allocator_->GetRandomMmapAddr();
}
void* AllocatePages(void* address, size_t size, size_t alignment,
PageAllocator::Permission access) override {
void* result =
page_allocator_->AllocatePages(address, size, alignment, access);
if (result) {
// Mark pages as used.
Address current_page = reinterpret_cast<Address>(result);
CHECK(IsAligned(current_page, allocate_page_size_));
CHECK(IsAligned(size, allocate_page_size_));
CHECK(region_allocator_.AllocateRegionAt(current_page, size));
Address end = current_page + size;
while (current_page < end) {
page_permissions_.insert({current_page, access});
current_page += commit_page_size_;
}
}
return result;
}
bool FreePages(void* address, size_t size) override {
bool result = page_allocator_->FreePages(address, size);
if (result) {
// Mark pages as free.
Address start = reinterpret_cast<Address>(address);
CHECK(IsAligned(start, allocate_page_size_));
CHECK(IsAligned(size, allocate_page_size_));
size_t freed_size = region_allocator_.FreeRegion(start);
CHECK(IsAligned(freed_size, commit_page_size_));
CHECK_EQ(RoundUp(freed_size, allocate_page_size_), size);
auto start_iter = page_permissions_.find(start);
CHECK_NE(start_iter, page_permissions_.end());
auto end_iter = page_permissions_.lower_bound(start + size);
page_permissions_.erase(start_iter, end_iter);
}
return result;
}
bool ReleasePages(void* address, size_t size, size_t new_size) override {
bool result = page_allocator_->ReleasePages(address, size, new_size);
if (result) {
Address start = reinterpret_cast<Address>(address);
CHECK(IsAligned(start, allocate_page_size_));
CHECK(IsAligned(size, commit_page_size_));
CHECK(IsAligned(new_size, commit_page_size_));
CHECK_LT(new_size, size);
CHECK_EQ(region_allocator_.TrimRegion(start, new_size), size - new_size);
auto start_iter = page_permissions_.find(start + new_size);
CHECK_NE(start_iter, page_permissions_.end());
auto end_iter = page_permissions_.lower_bound(start + size);
page_permissions_.erase(start_iter, end_iter);
}
return result;
}
bool SetPermissions(void* address, size_t size,
PageAllocator::Permission access) override {
bool result = page_allocator_->SetPermissions(address, size, access);
if (result) {
UpdatePagePermissions(reinterpret_cast<Address>(address), size, access);
}
return result;
}
// Returns true if all the allocated pages were freed.
bool IsEmpty() { return page_permissions_.empty(); }
void CheckIsFree(Address address, size_t size) {
CHECK(IsAligned(address, allocate_page_size_));
CHECK(IsAligned(size, allocate_page_size_));
EXPECT_TRUE(region_allocator_.IsFree(address, size));
}
void CheckPagePermissions(Address address, size_t size,
PageAllocator::Permission access) {
ForEachPage(address, size, [=](PagePermissionsMap::value_type* value) {
EXPECT_EQ(access, value->second);
});
}
void Print(const char* comment) const {
i::StdoutStream os;
os << "\n========================================="
<< "\nTracingPageAllocator state: ";
if (comment) os << comment;
os << "\n-----------------------------------------\n";
region_allocator_.Print(os);
os << "-----------------------------------------"
<< "\nPage permissions:";
if (page_permissions_.empty()) {
os << " empty\n";
return;
}
os << "\n" << std::hex << std::showbase;
Address contiguous_region_start = static_cast<Address>(-1);
Address contiguous_region_end = contiguous_region_start;
PageAllocator::Permission contiguous_region_access =
PageAllocator::kNoAccess;
for (auto& pair : page_permissions_) {
if (contiguous_region_end == pair.first &&
pair.second == contiguous_region_access) {
contiguous_region_end += commit_page_size_;
continue;
}
if (contiguous_region_start != contiguous_region_end) {
PrintRegion(os, contiguous_region_start, contiguous_region_end,
contiguous_region_access);
}
contiguous_region_start = pair.first;
contiguous_region_end = pair.first + commit_page_size_;
contiguous_region_access = pair.second;
}
if (contiguous_region_start != contiguous_region_end) {
PrintRegion(os, contiguous_region_start, contiguous_region_end,
contiguous_region_access);
}
}
private:
using PagePermissionsMap = std::map<Address, PageAllocator::Permission>;
using ForEachFn = std::function<void(PagePermissionsMap::value_type*)>;
static void PrintRegion(std::ostream& os, Address start, Address end,
PageAllocator::Permission access) {
os << " page: [" << start << ", " << end << "), access: ";
switch (access) {
case PageAllocator::kNoAccess:
os << "--";
break;
case PageAllocator::kRead:
os << "R";
break;
case PageAllocator::kReadWrite:
os << "RW";
break;
case PageAllocator::kReadWriteExecute:
os << "RWX";
break;
case PageAllocator::kReadExecute:
os << "RX";
break;
}
os << "\n";
}
void ForEachPage(Address address, size_t size, const ForEachFn& fn) {
CHECK(IsAligned(address, commit_page_size_));
CHECK(IsAligned(size, commit_page_size_));
auto start_iter = page_permissions_.find(address);
// Start page must exist in page_permissions_.
CHECK_NE(start_iter, page_permissions_.end());
auto end_iter = page_permissions_.find(address + size - commit_page_size_);
// Ensure the last but one page exists in page_permissions_.
CHECK_NE(end_iter, page_permissions_.end());
// Now make it point to the next element in order to also process is by the
// following for loop.
++end_iter;
for (auto iter = start_iter; iter != end_iter; ++iter) {
PagePermissionsMap::value_type& pair = *iter;
fn(&pair);
}
}
void UpdatePagePermissions(Address address, size_t size,
PageAllocator::Permission access) {
ForEachPage(address, size, [=](PagePermissionsMap::value_type* value) {
value->second = access;
});
}
v8::PageAllocator* const page_allocator_;
const size_t allocate_page_size_;
const size_t commit_page_size_;
// Region allocator tracks page allocation/deallocation requests.
base::RegionAllocator region_allocator_;
// This map keeps track of allocated pages' permissions.
PagePermissionsMap page_permissions_;
};
class SequentialUnmapperTest : public TestWithIsolate {
public:
SequentialUnmapperTest() = default;
~SequentialUnmapperTest() override = default;
static void SetUpTestCase() {
CHECK_NULL(tracking_page_allocator_);
old_page_allocator_ = GetPlatformPageAllocator();
tracking_page_allocator_ = new TrackingPageAllocator(old_page_allocator_);
CHECK(tracking_page_allocator_->IsEmpty());
CHECK_EQ(old_page_allocator_,
SetPlatformPageAllocatorForTesting(tracking_page_allocator_));
old_flag_ = i::FLAG_concurrent_sweeping;
i::FLAG_concurrent_sweeping = false;
TestWithIsolate::SetUpTestCase();
}
static void TearDownTestCase() {
TestWithIsolate::TearDownTestCase();
i::FLAG_concurrent_sweeping = old_flag_;
CHECK(tracking_page_allocator_->IsEmpty());
delete tracking_page_allocator_;
tracking_page_allocator_ = nullptr;
}
Heap* heap() { return isolate()->heap(); }
MemoryAllocator* allocator() { return heap()->memory_allocator(); }
MemoryAllocator::Unmapper* unmapper() { return allocator()->unmapper(); }
TrackingPageAllocator* tracking_page_allocator() {
return tracking_page_allocator_;
}
private:
static TrackingPageAllocator* tracking_page_allocator_;
static v8::PageAllocator* old_page_allocator_;
static bool old_flag_;
DISALLOW_COPY_AND_ASSIGN(SequentialUnmapperTest);
};
TrackingPageAllocator* SequentialUnmapperTest::tracking_page_allocator_ =
nullptr;
v8::PageAllocator* SequentialUnmapperTest::old_page_allocator_ = nullptr;
bool SequentialUnmapperTest::old_flag_;
// TODO(v8:7464): Enable these once there is a good way to free the shared
// read-only space.
#ifndef V8_SHARED_RO_HEAP
// See v8:5945.
TEST_F(SequentialUnmapperTest, UnmapOnTeardownAfterAlreadyFreeingPooled) {
Page* page = allocator()->AllocatePage(
MemoryChunkLayout::AllocatableMemoryInDataPage(),
static_cast<PagedSpace*>(heap()->old_space()),
Executability::NOT_EXECUTABLE);
EXPECT_NE(nullptr, page);
const size_t page_size = tracking_page_allocator()->AllocatePageSize();
tracking_page_allocator()->CheckPagePermissions(page->address(), page_size,
PageAllocator::kReadWrite);
allocator()->Free<MemoryAllocator::kPooledAndQueue>(page);
tracking_page_allocator()->CheckPagePermissions(page->address(), page_size,
PageAllocator::kReadWrite);
unmapper()->FreeQueuedChunks();
tracking_page_allocator()->CheckPagePermissions(page->address(), page_size,
PageAllocator::kNoAccess);
unmapper()->TearDown();
if (i_isolate()->isolate_allocation_mode() ==
IsolateAllocationMode::kInV8Heap) {
// In this mode Isolate uses bounded page allocator which allocates pages
// inside prereserved region. Thus these pages are kept reserved until
// the Isolate dies.
tracking_page_allocator()->CheckPagePermissions(page->address(), page_size,
PageAllocator::kNoAccess);
} else {
CHECK_EQ(IsolateAllocationMode::kInCppHeap,
i_isolate()->isolate_allocation_mode());
tracking_page_allocator()->CheckIsFree(page->address(), page_size);
}
}
// See v8:5945.
TEST_F(SequentialUnmapperTest, UnmapOnTeardown) {
Page* page = allocator()->AllocatePage(
MemoryChunkLayout::AllocatableMemoryInDataPage(),
static_cast<PagedSpace*>(heap()->old_space()),
Executability::NOT_EXECUTABLE);
EXPECT_NE(nullptr, page);
const size_t page_size = tracking_page_allocator()->AllocatePageSize();
tracking_page_allocator()->CheckPagePermissions(page->address(), page_size,
PageAllocator::kReadWrite);
allocator()->Free<MemoryAllocator::kPooledAndQueue>(page);
tracking_page_allocator()->CheckPagePermissions(page->address(), page_size,
PageAllocator::kReadWrite);
unmapper()->TearDown();
if (i_isolate()->isolate_allocation_mode() ==
IsolateAllocationMode::kInV8Heap) {
// In this mode Isolate uses bounded page allocator which allocates pages
// inside prereserved region. Thus these pages are kept reserved until
// the Isolate dies.
tracking_page_allocator()->CheckPagePermissions(page->address(), page_size,
PageAllocator::kNoAccess);
} else {
CHECK_EQ(IsolateAllocationMode::kInCppHeap,
i_isolate()->isolate_allocation_mode());
tracking_page_allocator()->CheckIsFree(page->address(), page_size);
}
}
#endif // V8_SHARED_RO_HEAP
} // namespace internal
} // namespace v8