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* Copyright (C) 2011 Apple Inc. All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "DFGDominators.h"
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namespace JSC { namespace DFG {
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Dominators::Dominators()
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Dominators::~Dominators()
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void Dominators::compute(Graph& graph)
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// This implements a naive dominator solver.
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ASSERT(graph.m_blocks[0]->m_predecessors.isEmpty());
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unsigned numBlocks = graph.m_blocks.size();
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if (numBlocks > m_results.size()) {
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m_results.grow(numBlocks);
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for (unsigned i = numBlocks; i--;)
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m_results[i].resize(numBlocks);
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m_scratch.resize(numBlocks);
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m_results[0].clearAll();
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for (unsigned i = numBlocks; i--;) {
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if (!graph.m_blocks[i])
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for (unsigned i = numBlocks; i-- > 1;) {
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if (!graph.m_blocks[i] || graph.m_blocks[i]->m_predecessors.isEmpty())
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m_results[i].clearAll();
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m_results[i].set(m_scratch);
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for (unsigned i = 1; i < numBlocks; ++i)
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changed |= iterateForBlock(graph, i);
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for (unsigned i = numBlocks; i-- > 1;)
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changed |= iterateForBlock(graph, i);
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bool Dominators::iterateForBlock(Graph& graph, BlockIndex i)
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BasicBlock* block = graph.m_blocks[i].get();
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if (block->m_predecessors.isEmpty())
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m_scratch.set(m_results[block->m_predecessors[0]]);
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for (unsigned j = block->m_predecessors.size(); j-- > 1;)
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m_scratch.filter(m_results[block->m_predecessors[j]]);
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return m_results[i].setAndCheck(m_scratch);
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} } // namespace JSC::DFG
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#endif // ENABLE(DFG_JIT)