cshapiro@google.com
0928c651e5
The previous algorithm would visit each pointer in the heap and verify it without regard for whether the pointer had already been visited. The new algorithm computes the set of allocated objects and verifies each object in the set. In a second pass, each pointer is visited and tested for membership in the set. BUG=2606 Review URL: https://chromiumcodereview.appspot.com//10696029 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@9532 260f80e4-7a28-3924-810f-c04153c831b5
75 lines
1.9 KiB
C++
75 lines
1.9 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_OBJECT_SET_H_
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#define VM_OBJECT_SET_H_
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#include "vm/globals.h"
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namespace dart {
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class ObjectSet {
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public:
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ObjectSet(uword start, uword end) : start_(start), end_(end) {
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ASSERT(start_ <= end_);
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size_ = SizeFor((end_ - start_) >> kWordSizeLog2);
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allocation_ = new uword[size_];
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data_ = &allocation_[-((start >> kWordSizeLog2) / kBitsPerWord)];
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ASSERT(allocation_ == &data_[(start >> kWordSizeLog2) / kBitsPerWord]);
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Clear();
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}
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~ObjectSet() {
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delete[] allocation_;
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}
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bool Contains(RawObject* raw_obj) const {
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uword raw_addr = RawObject::ToAddr(raw_obj);
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ASSERT(raw_addr >= start_);
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ASSERT(raw_addr < end_);
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uword i = raw_addr >> kWordSizeLog2;
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uword mask = (static_cast<uword>(1) << (i % kBitsPerWord));
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return (data_[i / kBitsPerWord] & mask) != 0;
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}
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void Add(RawObject* raw_obj) {
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uword raw_addr = RawObject::ToAddr(raw_obj);
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ASSERT(raw_addr >= start_);
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ASSERT(raw_addr < end_);
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uword i = raw_addr >> kWordSizeLog2;
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data_[i / kBitsPerWord] |= (static_cast<uword>(1) << (i % kBitsPerWord));
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}
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void Clear() {
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memset(allocation_, 0, (size_ * sizeof(allocation_[0])));
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}
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private:
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static intptr_t SizeFor(intptr_t length) {
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return 1 + ((length - 1) / kBitsPerWord);
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}
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// Biased data pointer aliased to allocation_. This value can be
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// indexed without adjusting for the starting address of the heap.
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uword* data_;
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// Allocated data pointer.
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uword* allocation_;
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// Allocation size in uwords.
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intptr_t size_;
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// Lowest possible heap address, inclusive.
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uword start_;
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// Highest possible heap address, exclusive.
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uword end_;
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DISALLOW_IMPLICIT_CONSTRUCTORS(ObjectSet);
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};
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} // namespace dart
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#endif // VM_OBJECT_SET_H_
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