Ryan Macnak
9764a9f037
-Pre-mark instructions when writing the snapshot. -Write the megamorphic miss function to the snapshot. -Add missing ExceptionHandlers for megamorphic miss code. -Add missing C++ entry points. -Relocate Function and Code entry_points_ when reading precompiled snapshot. -Don't try to load a script again when running from a precompiled snapshot. R=asiva@google.com Review URL: https://codereview.chromium.org//1336763002 .
101 lines
3.0 KiB
C++
101 lines
3.0 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 VM_VIRTUAL_MEMORY_H_
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#define VM_VIRTUAL_MEMORY_H_
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#include "platform/utils.h"
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#include "vm/globals.h"
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#include "vm/memory_region.h"
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namespace dart {
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class VirtualMemory {
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public:
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enum Protection {
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kNoAccess,
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kReadOnly,
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kReadWrite,
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kReadExecute,
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kReadWriteExecute
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};
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// The reserved memory is unmapped on destruction.
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~VirtualMemory();
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uword start() const { return region_.start(); }
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uword end() const { return region_.end(); }
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void* address() const { return region_.pointer(); }
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intptr_t size() const { return region_.size(); }
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static void InitOnce();
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bool Contains(uword addr) const {
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return region_.Contains(addr);
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}
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// Commits the virtual memory area, which is guaranteed to be zeroed. Returns
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// true on success and false on failure (e.g., out-of-memory).
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bool Commit(bool is_executable) {
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return Commit(start(), size(), is_executable);
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}
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// Changes the protection of the virtual memory area.
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static bool Protect(void* address, intptr_t size, Protection mode);
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bool Protect(Protection mode) {
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return Protect(address(), size(), mode);
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}
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// Reserves a virtual memory segment with size. If a segment of the requested
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// size cannot be allocated NULL is returned.
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static VirtualMemory* Reserve(intptr_t size) {
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return ReserveInternal(size);
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}
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static intptr_t PageSize() {
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ASSERT(page_size_ != 0);
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ASSERT(Utils::IsPowerOfTwo(page_size_));
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return page_size_;
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}
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static bool InSamePage(uword address0, uword address1);
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// Truncate this virtual memory segment. If try_unmap is false, the
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// memory beyond the new end is still accessible, but will be returned
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// upon destruction.
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void Truncate(intptr_t new_size, bool try_unmap = true);
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// Commit a reserved memory area, so that the memory can be accessed.
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bool Commit(uword addr, intptr_t size, bool is_executable);
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static VirtualMemory* ForInstructionsSnapshot(void* pointer, uword size);
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private:
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static VirtualMemory* ReserveInternal(intptr_t size);
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// Free a sub segment. On operating systems that support it this
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// can give back the virtual memory to the system. Returns true on success.
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static bool FreeSubSegment(void* address, intptr_t size);
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// This constructor is only used internally when reserving new virtual spaces.
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// It does not reserve any virtual address space on its own.
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explicit VirtualMemory(const MemoryRegion& region) :
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region_(region.pointer(), region.size()),
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reserved_size_(region.size()) { }
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MemoryRegion region_;
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// The size of the underlying reservation not yet given back to the OS.
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// Its start coincides with region_, but its size might not, due to Truncate.
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intptr_t reserved_size_;
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static uword page_size_;
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DISALLOW_IMPLICIT_CONSTRUCTORS(VirtualMemory);
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};
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} // namespace dart
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#endif // VM_VIRTUAL_MEMORY_H_
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