Vyacheslav Egorov
613c6d066c
Fixes #27505
This relands fc775b3e9b with a fix to
VirtualMemory::~VirtualMemory: on Windows the only way to release
virtual address mapping is to invoke VirtualFree(..., MEM_RELEASE) with the
original base pointer returned by VirtualAlloc - that is why we need to call
VirtualFree is size of the reservation is 0: the whole reservation might have
been decommitted by VirtualFree(MEM_DECOMMIT) but it is still present.
Change-Id: I7d1d444693c523b327d44266d5fe70f7a5d8f803
Reviewed-on: https://dart-review.googlesource.com/52642
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
119 lines
3.7 KiB
C++
119 lines
3.7 KiB
C++
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#include "vm/globals.h"
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#if defined(HOST_OS_WINDOWS)
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#include "vm/virtual_memory.h"
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#include "platform/assert.h"
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#include "vm/os.h"
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#include "vm/isolate.h"
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namespace dart {
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uword VirtualMemory::page_size_ = 0;
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void VirtualMemory::InitOnce() {
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SYSTEM_INFO info;
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GetSystemInfo(&info);
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page_size_ = info.dwPageSize;
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}
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VirtualMemory* VirtualMemory::Allocate(intptr_t size,
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bool is_executable,
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const char* name) {
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ASSERT(Utils::IsAligned(size, page_size_));
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int prot = is_executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
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void* address = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT, prot);
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if (address == NULL) {
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return NULL;
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}
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MemoryRegion region(address, size);
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return new VirtualMemory(region, region);
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}
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VirtualMemory* VirtualMemory::AllocateAligned(intptr_t size,
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intptr_t alignment,
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bool is_executable,
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const char* name) {
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ASSERT(Utils::IsAligned(size, page_size_));
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ASSERT(Utils::IsAligned(alignment, page_size_));
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intptr_t reserved_size = size + alignment;
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int prot = is_executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
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void* address = VirtualAlloc(NULL, reserved_size, MEM_RESERVE, prot);
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if (address == NULL) {
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return NULL;
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}
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void* aligned_address = reinterpret_cast<void*>(
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Utils::RoundUp(reinterpret_cast<uword>(address), alignment));
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if (VirtualAlloc(aligned_address, size, MEM_COMMIT, prot) !=
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aligned_address) {
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VirtualFree(address, reserved_size, MEM_RELEASE);
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return NULL;
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}
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MemoryRegion region(aligned_address, size);
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MemoryRegion reserved(address, reserved_size);
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return new VirtualMemory(region, reserved);
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}
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VirtualMemory::~VirtualMemory() {
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// Note that the size of the reserved region might be set to 0 by
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// Truncate(0, true) but that does not actually release the mapping
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// itself. The only way to release the mapping is to invoke VirtualFree
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// with original base pointer and MEM_RELEASE.
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if (!vm_owns_region()) {
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return;
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}
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if (VirtualFree(reserved_.pointer(), 0, MEM_RELEASE) == 0) {
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FATAL1("VirtualFree failed: Error code %d\n", GetLastError());
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}
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}
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bool VirtualMemory::FreeSubSegment(void* address,
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intptr_t size) {
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if (VirtualFree(address, size, MEM_DECOMMIT) == 0) {
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FATAL1("VirtualFree failed: Error code %d\n", GetLastError());
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}
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return true;
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}
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void VirtualMemory::Protect(void* address, intptr_t size, Protection mode) {
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ASSERT(Thread::Current()->IsMutatorThread() ||
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Isolate::Current()->mutator_thread()->IsAtSafepoint());
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uword start_address = reinterpret_cast<uword>(address);
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uword end_address = start_address + size;
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uword page_address = Utils::RoundDown(start_address, PageSize());
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DWORD prot = 0;
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switch (mode) {
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case kNoAccess:
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prot = PAGE_NOACCESS;
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break;
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case kReadOnly:
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prot = PAGE_READONLY;
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break;
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case kReadWrite:
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prot = PAGE_READWRITE;
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break;
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case kReadExecute:
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prot = PAGE_EXECUTE_READ;
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break;
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case kReadWriteExecute:
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prot = PAGE_EXECUTE_READWRITE;
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break;
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}
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DWORD old_prot = 0;
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if (VirtualProtect(reinterpret_cast<void*>(page_address),
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end_address - page_address, prot, &old_prot) == 0) {
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FATAL1("VirtualProtect failed %d\n", GetLastError());
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}
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}
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} // namespace dart
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#endif // defined(HOST_OS_WINDOWS)
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