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
100 lines
3.1 KiB
C++
100 lines
3.1 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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#include "vm/bitmap.h"
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#include "platform/assert.h"
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#include "vm/object.h"
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namespace dart {
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void BitmapBuilder::SetLength(intptr_t new_length) {
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// When this function is used to shorten the length, affected bits in the
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// backing store need to be cleared because the implementation assumes it.
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if (new_length < length_) {
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// Byte offset containing the first bit to be cleared.
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intptr_t byte_offset = new_length >> kBitsPerByteLog2;
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if (byte_offset < data_size_in_bytes_) {
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// First bit index (in the byte) to be cleared.
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intptr_t bit_index = new_length & (kBitsPerByte - 1);
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intptr_t mask = (1 << bit_index) - 1;
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data_[byte_offset] &= mask;
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// Clear the rest.
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++byte_offset;
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if (byte_offset < data_size_in_bytes_) {
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memset(&data_[byte_offset], 0, data_size_in_bytes_ - byte_offset);
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}
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}
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}
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length_ = new_length;
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}
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bool BitmapBuilder::Get(intptr_t bit_offset) const {
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ASSERT(InRange(bit_offset));
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intptr_t byte_offset = bit_offset >> kBitsPerByteLog2;
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// Bits not covered by the backing store are implicitly false.
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return (byte_offset < data_size_in_bytes_) && GetBit(bit_offset);
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}
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void BitmapBuilder::Set(intptr_t bit_offset, bool value) {
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ASSERT(bit_offset >= 0);
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if (!InRange(bit_offset)) {
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length_ = bit_offset + 1;
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// Bits not covered by the backing store are implicitly false.
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if (!value) return;
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// Grow the backing store if necessary.
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intptr_t byte_offset = bit_offset >> kBitsPerByteLog2;
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if (byte_offset >= data_size_in_bytes_) {
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uint8_t* old_data = data_;
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intptr_t old_size = data_size_in_bytes_;
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data_size_in_bytes_ =
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Utils::RoundUp(byte_offset + 1, kIncrementSizeInBytes);
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ASSERT(data_size_in_bytes_ > 0);
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data_ = Isolate::Current()->current_zone()->Alloc<uint8_t>(
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data_size_in_bytes_);
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ASSERT(data_ != NULL);
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memmove(data_, old_data, old_size);
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memset(&data_[old_size], 0, (data_size_in_bytes_ - old_size));
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}
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}
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SetBit(bit_offset, value);
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}
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void BitmapBuilder::SetRange(intptr_t min, intptr_t max, bool value) {
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for (intptr_t i = min; i <= max; i++) {
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Set(i, value);
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}
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}
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bool BitmapBuilder::GetBit(intptr_t bit_offset) const {
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ASSERT(InRange(bit_offset));
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intptr_t byte_offset = bit_offset >> kBitsPerByteLog2;
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ASSERT(byte_offset < data_size_in_bytes_);
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intptr_t bit_remainder = bit_offset & (kBitsPerByte - 1);
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uint8_t mask = 1U << bit_remainder;
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ASSERT(data_ != NULL);
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return ((data_[byte_offset] & mask) != 0);
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}
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void BitmapBuilder::SetBit(intptr_t bit_offset, bool value) {
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ASSERT(InRange(bit_offset));
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int byte_offset = bit_offset >> kBitsPerByteLog2;
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ASSERT(byte_offset < data_size_in_bytes_);
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int bit_remainder = bit_offset & (kBitsPerByte - 1);
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uint8_t mask = 1U << bit_remainder;
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ASSERT(data_ != NULL);
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if (value) {
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data_[byte_offset] |= mask;
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} else {
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data_[byte_offset] &= ~mask;
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}
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}
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} // namespace dart
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