kmillikin@google.com
57f5dbafd6
The bitmaps describing the stack have an explicit length field. It is now an assertion failure to read bits outside the length --- they are no longer assumed to be false. Also remove an unused method and simplify the implementation of BitmapBuilder by removing an embedded member that was always referred to via a pointer. R=vegorov@google.com BUG= Review URL: https://chromiumcodereview.appspot.com//10832410 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@11138 260f80e4-7a28-3924-810f-c04153c831b5
75 lines
2.1 KiB
C++
75 lines
2.1 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_BITMAP_H_
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#define VM_BITMAP_H_
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#include "vm/allocation.h"
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#include "vm/isolate.h"
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#include "vm/zone.h"
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namespace dart {
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// Forward declarations.
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class RawStackmap;
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class Stackmap;
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// BitmapBuilder is used to build a bitmap. The implementation is optimized
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// for a dense set of small bit maps without a fixed upper bound (e.g: a
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// pointer map description of a stack).
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class BitmapBuilder : public ZoneAllocated {
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public:
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BitmapBuilder()
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: length_(0),
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data_size_in_bytes_(kInitialSizeInBytes),
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data_(Isolate::Current()->current_zone()->Alloc<uint8_t>(
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kInitialSizeInBytes)) {
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memset(data_, 0, kInitialSizeInBytes);
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}
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intptr_t Length() const { return length_; }
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void SetLength(intptr_t length);
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// Get/Set individual bits in the bitmap, setting bits beyond the bitmap's
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// length increases the length and expands the underlying bitmap if
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// needed.
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bool Get(intptr_t bit_offset) const;
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void Set(intptr_t bit_offset, bool value);
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// Return the bit offset of the highest bit set.
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intptr_t Maximum() const;
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// Return the bit offset of the lowest bit set.
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intptr_t Minimum() const;
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// Sets min..max (inclusive) to value.
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void SetRange(intptr_t min, intptr_t max, bool value);
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private:
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static const intptr_t kInitialSizeInBytes = 16;
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static const intptr_t kIncrementSizeInBytes = 16;
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bool InRange(intptr_t offset) const {
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return (offset >= 0) && (offset < length_);
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}
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// Get/Set a bit that is known to be covered by the backing store.
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bool GetBit(intptr_t bit_offset) const;
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void SetBit(intptr_t bit_offset, bool value);
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intptr_t length_;
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// Backing store for the bitmap. Reading bits beyond the backing store
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// (up to length_) is allowed and they are assumed to be false.
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intptr_t data_size_in_bytes_;
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uint8_t* data_;
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DISALLOW_COPY_AND_ASSIGN(BitmapBuilder);
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};
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} // namespace dart
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#endif // VM_BITMAP_H_
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