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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/virtual_memory.h"
#include "platform/assert.h"
#include "platform/utils.h"
namespace dart {
bool VirtualMemory::InSamePage(uword address0, uword address1) {
return (Utils::RoundDown(address0, PageSize()) ==
Utils::RoundDown(address1, PageSize()));
}
void VirtualMemory::Truncate(intptr_t new_size, bool try_unmap) {
ASSERT((new_size & (PageSize() - 1)) == 0);
ASSERT(new_size <= size());
if (try_unmap &&
(reserved_.size() ==
region_.size()) && /* Don't create holes in reservation. */
FreeSubSegment(reinterpret_cast<void*>(start() + new_size),
size() - new_size)) {
reserved_.set_size(new_size);
}
region_.Subregion(region_, 0, new_size);
}
VirtualMemory* VirtualMemory::ForImagePage(void* pointer, uword size) {
// Memory for precompilated instructions was allocated by the embedder, so
// create a VirtualMemory without allocating.
MemoryRegion region(pointer, size);
MemoryRegion reserved(0, 0); // NULL reservation indicates VM should not
// attempt to free this memory.
VirtualMemory* memory = new VirtualMemory(region, reserved);
ASSERT(!memory->vm_owns_region());
return memory;
}
} // namespace dart