mirror of
https://github.com/darlinghq/darling-JavaScriptCore.git
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103 lines
3.6 KiB
C++
103 lines
3.6 KiB
C++
/*
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* Copyright (C) 2013 Apple Inc. All rights reserved.
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*
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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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* are met:
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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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*
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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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*/
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#include "config.h"
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#include "DFGCriticalEdgeBreakingPhase.h"
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#if ENABLE(DFG_JIT)
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#include "DFGBasicBlockInlines.h"
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#include "DFGBlockInsertionSet.h"
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#include "DFGGraph.h"
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#include "DFGPhase.h"
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#include "JSCJSValueInlines.h"
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namespace JSC { namespace DFG {
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class CriticalEdgeBreakingPhase : public Phase {
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public:
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CriticalEdgeBreakingPhase(Graph& graph)
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: Phase(graph, "critical edge breaking")
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, m_insertionSet(graph)
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{
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}
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bool run()
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{
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for (BlockIndex blockIndex = 0; blockIndex < m_graph.numBlocks(); ++blockIndex) {
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BasicBlock* block = m_graph.block(blockIndex);
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if (!block)
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continue;
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// An edge A->B is critical if A has multiple successor and B has multiple
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// predecessors. Thus we fail early if we don't have multiple successors.
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if (block->numSuccessors() <= 1)
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continue;
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// Break critical edges by inserting a "Jump" pad block in place of each
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// unique A->B critical edge.
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HashMap<BasicBlock*, BasicBlock*> successorPads;
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for (unsigned i = block->numSuccessors(); i--;) {
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BasicBlock** successor = &block->successor(i);
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if ((*successor)->predecessors.size() <= 1)
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continue;
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BasicBlock* pad = nullptr;
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auto iter = successorPads.find(*successor);
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if (iter == successorPads.end()) {
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pad = m_insertionSet.insertBefore(*successor, (*successor)->executionCount);
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pad->appendNode(
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m_graph, SpecNone, Jump, (*successor)->at(0)->origin, OpInfo(*successor));
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pad->predecessors.append(block);
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(*successor)->replacePredecessor(block, pad);
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successorPads.set(*successor, pad);
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} else
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pad = iter->value;
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*successor = pad;
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}
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}
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return m_insertionSet.execute();
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}
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private:
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BlockInsertionSet m_insertionSet;
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};
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bool performCriticalEdgeBreaking(Graph& graph)
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{
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return runPhase<CriticalEdgeBreakingPhase>(graph);
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}
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} } // namespace JSC::DFG
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#endif // ENABLE(DFG_JIT)
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