Ryan Macnak
877284947b
Like HOST_ARCH_*, HOST_OS_* describes the OS the VM is running on, which may be different from the OS the VM is generating code for during AOT compilation. Currently we conflate the two when emitting AOT as assembly, and we get away with it because Flutter only uses assembly for targeting iOS and one can only target iOS from a Mac, but we expect to use assembly for Android as well so native tools can unwind Dart frames. R=zra@google.com Review-Url: https://codereview.chromium.org/2750843003 .
102 lines
2.6 KiB
C++
102 lines
2.6 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::ReserveInternal(intptr_t size) {
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void* address = VirtualAlloc(NULL, size, MEM_RESERVE, PAGE_NOACCESS);
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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);
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}
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VirtualMemory::~VirtualMemory() {
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if (!vm_owns_region() || (reserved_size_ == 0)) {
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return;
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}
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if (VirtualFree(address(), 0, MEM_RELEASE) == 0) {
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FATAL("VirtualFree failed");
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}
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}
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bool VirtualMemory::FreeSubSegment(int32_t handle,
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void* address,
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intptr_t size) {
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// On Windows only the entire segment returned by VirtualAlloc
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// can be freed. Therefore we will have to waste these unused
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// virtual memory sub-segments.
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return false;
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}
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bool VirtualMemory::Commit(uword addr, intptr_t size, bool executable) {
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ASSERT(Contains(addr));
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ASSERT(Contains(addr + size) || (addr + size == end()));
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int prot = executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
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if (VirtualAlloc(reinterpret_cast<void*>(addr), size, MEM_COMMIT, prot) ==
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NULL) {
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return false;
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}
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return true;
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}
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bool 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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bool result = VirtualProtect(reinterpret_cast<void*>(page_address),
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end_address - page_address, prot, &old_prot);
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return result;
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}
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} // namespace dart
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#endif // defined(HOST_OS_WINDOWS)
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