mirror of
https://github.com/dart-lang/sdk
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b247090c9e
Allows quick access to the page header for any old-space object, which is a convenient place to keep forwarding information. Also combine the reserve and commit operations of VirtualMemory. Bug: https://github.com/dart-lang/sdk/issues/30978 Change-Id: Id3fe06932f7bef882bb1cc29d72441b0a3602eb6 Reviewed-on: https://dart-review.googlesource.com/17046 Reviewed-by: Erik Corry <erikcorry@google.com> Reviewed-by: Zach Anderson <zra@google.com>
130 lines
3.8 KiB
C++
130 lines
3.8 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_ANDROID)
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#include "vm/virtual_memory.h"
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#include <sys/mman.h> // NOLINT
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#include <unistd.h> // NOLINT
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#include "platform/assert.h"
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#include "platform/utils.h"
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#include "vm/isolate.h"
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namespace dart {
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// standard MAP_FAILED causes "error: use of old-style cast" as it
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// defines MAP_FAILED as ((void *) -1)
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#undef MAP_FAILED
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#define MAP_FAILED reinterpret_cast<void*>(-1)
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uword VirtualMemory::page_size_ = 0;
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void VirtualMemory::InitOnce() {
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page_size_ = getpagesize();
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}
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static void unmap(void* address, intptr_t size) {
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if (size == 0) {
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return;
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}
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if (munmap(address, size) != 0) {
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FATAL("munmap failed\n");
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}
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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 = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
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void* address = mmap(NULL, size, prot, MAP_PRIVATE | MAP_ANON, -1, 0);
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if (address == MAP_FAILED) {
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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 allocated_size = size + alignment;
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int prot = PROT_READ | PROT_WRITE | (is_executable ? PROT_EXEC : 0);
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void* address =
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mmap(NULL, allocated_size, prot, MAP_PRIVATE | MAP_ANON, -1, 0);
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if (address == MAP_FAILED) {
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return NULL;
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}
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uword base = reinterpret_cast<uword>(address);
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uword aligned_base = Utils::RoundUp(base, alignment);
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ASSERT(base <= aligned_base);
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if (base != aligned_base) {
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uword extra_leading_size = aligned_base - base;
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unmap(reinterpret_cast<void*>(base), extra_leading_size);
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allocated_size -= extra_leading_size;
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}
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if (allocated_size != size) {
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uword extra_trailing_size = allocated_size - size;
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unmap(reinterpret_cast<void*>(aligned_base + size), extra_trailing_size);
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}
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MemoryRegion region(reinterpret_cast<void*>(aligned_base), size);
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return new VirtualMemory(region, region);
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}
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VirtualMemory::~VirtualMemory() {
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if (vm_owns_region()) {
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unmap(reserved_.pointer(), reserved_.size());
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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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unmap(address, size);
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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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int prot = 0;
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switch (mode) {
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case kNoAccess:
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prot = PROT_NONE;
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break;
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case kReadOnly:
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prot = PROT_READ;
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break;
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case kReadWrite:
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prot = PROT_READ | PROT_WRITE;
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break;
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case kReadExecute:
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prot = PROT_READ | PROT_EXEC;
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break;
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case kReadWriteExecute:
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prot = PROT_READ | PROT_WRITE | PROT_EXEC;
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break;
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}
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return (mprotect(reinterpret_cast<void*>(page_address),
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end_address - page_address, prot) == 0);
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}
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} // namespace dart
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#endif // defined(HOST_OS_ANDROID)
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