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![Ryan Macnak](/assets/img/avatar_default.png)
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>
85 lines
2.4 KiB
C++
85 lines
2.4 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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#ifndef RUNTIME_VM_MEMORY_REGION_H_
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#define RUNTIME_VM_MEMORY_REGION_H_
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#include "platform/assert.h"
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#include "vm/allocation.h"
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#include "vm/globals.h"
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namespace dart {
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// Memory regions are useful for accessing memory with bounds check in
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// debug mode. They can be safely passed by value and do not assume ownership
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// of the region.
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class MemoryRegion : public ValueObject {
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public:
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MemoryRegion() : pointer_(NULL), size_(0) {}
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MemoryRegion(void* pointer, uword size) : pointer_(pointer), size_(size) {}
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MemoryRegion(const MemoryRegion& other) : ValueObject() { *this = other; }
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MemoryRegion& operator=(const MemoryRegion& other) {
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pointer_ = other.pointer_;
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size_ = other.size_;
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return *this;
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}
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void* pointer() const { return pointer_; }
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uword size() const { return size_; }
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void set_size(uword new_size) { size_ = new_size; }
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uword start() const { return reinterpret_cast<uword>(pointer_); }
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uword end() const { return start() + size_; }
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template <typename T>
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T Load(uword offset) const {
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return *ComputeInternalPointer<T>(offset);
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}
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template <typename T>
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void Store(uword offset, T value) const {
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*ComputeInternalPointer<T>(offset) = value;
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}
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template <typename T>
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T* PointerTo(uword offset) const {
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return ComputeInternalPointer<T>(offset);
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}
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bool Contains(uword address) const {
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return (address >= start()) && (address < end());
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}
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void CopyFrom(uword offset, const MemoryRegion& from) const;
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// Compute a sub memory region based on an existing one.
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void Subregion(const MemoryRegion& from, uword offset, uword size) {
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ASSERT(from.size() >= size);
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ASSERT(offset <= (from.size() - size));
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pointer_ = reinterpret_cast<void*>(from.start() + offset);
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size_ = size;
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}
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// Compute an extended memory region based on an existing one.
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void Extend(const MemoryRegion& region, uword extra) {
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pointer_ = region.pointer();
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size_ = (region.size() + extra);
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}
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private:
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template <typename T>
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T* ComputeInternalPointer(uword offset) const {
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ASSERT(size() >= sizeof(T));
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ASSERT(offset <= size() - sizeof(T));
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return reinterpret_cast<T*>(start() + offset);
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}
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void* pointer_;
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uword size_;
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};
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} // namespace dart
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#endif // RUNTIME_VM_MEMORY_REGION_H_
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