koda@google.com
2965f45064
Also add the ability to truncate without actually unmapping. Note: We never create holes in the underlying reservation. This CL is in preparation for using a thin wrapper around VirtualMemory to verify our upcoming concurrent write barrier. R=iposva@google.com Review URL: https://codereview.chromium.org//644453003 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@41017 260f80e4-7a28-3924-810f-c04153c831b5
31 lines
947 B
C++
31 lines
947 B
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/virtual_memory.h"
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#include "platform/assert.h"
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#include "platform/utils.h"
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namespace dart {
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bool VirtualMemory::InSamePage(uword address0, uword address1) {
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return (Utils::RoundDown(address0, PageSize()) ==
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Utils::RoundDown(address1, PageSize()));
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}
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void VirtualMemory::Truncate(intptr_t new_size, bool try_unmap) {
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ASSERT((new_size & (PageSize() - 1)) == 0);
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ASSERT(new_size <= size());
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if (try_unmap &&
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(reserved_size_ == size()) && /* Don't create holes in reservation. */
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FreeSubSegment(reinterpret_cast<void*>(start() + new_size),
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size() - new_size)) {
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reserved_size_ = new_size;
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}
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region_.Subregion(region_, 0, new_size);
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}
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} // namespace dart
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