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// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/globals.h"
#if defined(DART_HOST_OS_WINDOWS)
#include "vm/virtual_memory.h"
#include "platform/assert.h"
#include "vm/isolate.h"
#include "vm/os.h"
#include "vm/virtual_memory_compressed.h"
namespace dart {
DECLARE_FLAG(bool, write_protect_code);
uword VirtualMemory::page_size_ = 0;
VirtualMemory* VirtualMemory::compressed_heap_ = nullptr;
intptr_t VirtualMemory::CalculatePageSize() {
SYSTEM_INFO info;
GetSystemInfo(&info);
const intptr_t page_size = info.dwPageSize;
ASSERT(page_size != 0);
ASSERT(Utils::IsPowerOfTwo(page_size));
return page_size;
}
static void* AllocateAlignedImpl(intptr_t size,
intptr_t alignment,
intptr_t reserved_size,
int prot,
void** out_reserved_address) {
void* address = VirtualAlloc(nullptr, reserved_size, MEM_RESERVE, prot);
if (address == nullptr) {
return nullptr;
}
void* aligned_address = reinterpret_cast<void*>(
Utils::RoundUp(reinterpret_cast<uword>(address), alignment));
if (VirtualAlloc(aligned_address, size, MEM_COMMIT, prot) !=
aligned_address) {
VirtualFree(address, reserved_size, MEM_RELEASE);
return nullptr;
}
if (out_reserved_address != nullptr) {
*out_reserved_address = address;
}
return aligned_address;
}
void VirtualMemory::Init() {
if (FLAG_old_gen_heap_size < 0 || FLAG_old_gen_heap_size > kMaxAddrSpaceMB) {
OS::PrintErr(
"warning: value specified for --old_gen_heap_size %d is larger than"
" the physically addressable range, using 0(unlimited) instead.`\n",
FLAG_old_gen_heap_size);
FLAG_old_gen_heap_size = 0;
}
if (FLAG_new_gen_semi_max_size < 0 ||
FLAG_new_gen_semi_max_size > kMaxAddrSpaceMB) {
OS::PrintErr(
"warning: value specified for --new_gen_semi_max_size %d is larger"
" than the physically addressable range, using %" Pd " instead.`\n",
FLAG_new_gen_semi_max_size, kDefaultNewGenSemiMaxSize);
FLAG_new_gen_semi_max_size = kDefaultNewGenSemiMaxSize;
}
page_size_ = CalculatePageSize();
#if defined(DART_COMPRESSED_POINTERS)
ASSERT(compressed_heap_ == nullptr);
compressed_heap_ = Reserve(kCompressedHeapSize, kCompressedHeapAlignment);
if (compressed_heap_ == nullptr) {
int error = GetLastError();
FATAL("Failed to reserve region for compressed heap: %d", error);
}
VirtualMemoryCompressedHeap::Init(compressed_heap_->address(),
compressed_heap_->size());
#endif // defined(DART_COMPRESSED_POINTERS)
}
void VirtualMemory::Cleanup() {
#if defined(DART_COMPRESSED_POINTERS)
delete compressed_heap_;
#endif // defined(DART_COMPRESSED_POINTERS)
page_size_ = 0;
#if defined(DART_COMPRESSED_POINTERS)
compressed_heap_ = nullptr;
VirtualMemoryCompressedHeap::Cleanup();
#endif // defined(DART_COMPRESSED_POINTERS)
}
VirtualMemory* VirtualMemory::AllocateAligned(intptr_t size,
intptr_t alignment,
bool is_executable,
bool is_compressed,
const char* name) {
// When FLAG_write_protect_code is active, code memory (indicated by
// is_executable = true) is allocated as non-executable and later
// changed to executable via VirtualMemory::Protect.
ASSERT(Utils::IsAligned(size, PageSize()));
ASSERT(Utils::IsPowerOfTwo(alignment));
ASSERT(Utils::IsAligned(alignment, PageSize()));
#if defined(DART_COMPRESSED_POINTERS)
if (is_compressed) {
RELEASE_ASSERT(!is_executable);
MemoryRegion region =
VirtualMemoryCompressedHeap::Allocate(size, alignment);
if (region.pointer() == nullptr) {
return nullptr;
}
Commit(region.pointer(), region.size());
return new VirtualMemory(region, region);
}
#endif // defined(DART_COMPRESSED_POINTERS)
intptr_t reserved_size = size + alignment - PageSize();
int prot = (is_executable && !FLAG_write_protect_code)
? PAGE_EXECUTE_READWRITE
: PAGE_READWRITE;
void* reserved_address;
void* aligned_address = AllocateAlignedImpl(size, alignment, reserved_size,
prot, &reserved_address);
if (aligned_address == nullptr) {
return nullptr;
}
MemoryRegion region(aligned_address, size);
MemoryRegion reserved(reserved_address, reserved_size);
return new VirtualMemory(region, reserved);
}
VirtualMemory* VirtualMemory::Reserve(intptr_t size, intptr_t alignment) {
ASSERT(Utils::IsAligned(size, PageSize()));
ASSERT(Utils::IsPowerOfTwo(alignment));
ASSERT(Utils::IsAligned(alignment, PageSize()));
intptr_t reserved_size = size + alignment - PageSize();
void* reserved_address =
VirtualAlloc(nullptr, reserved_size, MEM_RESERVE, PAGE_NOACCESS);
if (reserved_address == nullptr) {
return nullptr;
}
void* aligned_address = reinterpret_cast<void*>(
Utils::RoundUp(reinterpret_cast<uword>(reserved_address), alignment));
MemoryRegion region(aligned_address, size);
MemoryRegion reserved(reserved_address, reserved_size);
return new VirtualMemory(region, reserved);
}
void VirtualMemory::Commit(void* address, intptr_t size) {
ASSERT(Utils::IsAligned(address, PageSize()));
ASSERT(Utils::IsAligned(size, PageSize()));
void* result = VirtualAlloc(address, size, MEM_COMMIT, PAGE_READWRITE);
if (result == nullptr) {
int error = GetLastError();
FATAL("Failed to commit: %d\n", error);
}
}
void VirtualMemory::Decommit(void* address, intptr_t size) {
ASSERT(Utils::IsAligned(address, PageSize()));
ASSERT(Utils::IsAligned(size, PageSize()));
bool result = VirtualFree(address, size, MEM_DECOMMIT);
if (!result) {
int error = GetLastError();
FATAL("Failed to decommit: %d\n", error);
}
}
VirtualMemory::~VirtualMemory() {
// Note that the size of the reserved region might be set to 0 by
// Truncate(0, true) but that does not actually release the mapping
// itself. The only way to release the mapping is to invoke VirtualFree
// with original base pointer and MEM_RELEASE.
#if defined(DART_COMPRESSED_POINTERS)
if (VirtualMemoryCompressedHeap::Contains(reserved_.pointer()) &&
(this != compressed_heap_)) {
Decommit(reserved_.pointer(), reserved_.size());
VirtualMemoryCompressedHeap::Free(reserved_.pointer(), reserved_.size());
return;
}
#endif // defined(DART_COMPRESSED_POINTERS)
if (!vm_owns_region()) {
return;
}
if (VirtualFree(reserved_.pointer(), 0, MEM_RELEASE) == 0) {
FATAL("VirtualFree failed: Error code %d\n", GetLastError());
}
}
bool VirtualMemory::FreeSubSegment(void* address, intptr_t size) {
#if defined(DART_COMPRESSED_POINTERS)
// Don't free the sub segment if it's managed by the compressed pointer heap.
if (VirtualMemoryCompressedHeap::Contains(address)) {
return false;
}
#endif // defined(DART_COMPRESSED_POINTERS)
if (VirtualFree(address, size, MEM_DECOMMIT) == 0) {
FATAL("VirtualFree failed: Error code %d\n", GetLastError());
}
return true;
}
void VirtualMemory::Protect(void* address, intptr_t size, Protection mode) {
#if defined(DEBUG)
Thread* thread = Thread::Current();
ASSERT(thread == nullptr || thread->IsDartMutatorThread() ||
thread->isolate() == nullptr ||
thread->isolate()->mutator_thread()->IsAtSafepoint());
#endif
uword start_address = reinterpret_cast<uword>(address);
uword end_address = start_address + size;
uword page_address = Utils::RoundDown(start_address, PageSize());
DWORD prot = 0;
switch (mode) {
case kNoAccess:
prot = PAGE_NOACCESS;
break;
case kReadOnly:
prot = PAGE_READONLY;
break;
case kReadWrite:
prot = PAGE_READWRITE;
break;
case kReadExecute:
prot = PAGE_EXECUTE_READ;
break;
case kReadWriteExecute:
prot = PAGE_EXECUTE_READWRITE;
break;
}
DWORD old_prot = 0;
if (VirtualProtect(reinterpret_cast<void*>(page_address),
end_address - page_address, prot, &old_prot) == 0) {
FATAL("VirtualProtect failed %d\n", GetLastError());
}
}
void VirtualMemory::DontNeed(void* address, intptr_t size) {}
} // namespace dart
#endif // defined(DART_HOST_OS_WINDOWS)