mirror of
https://github.com/darlinghq/darling-JavaScriptCore.git
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113 lines
3.7 KiB
C++
113 lines
3.7 KiB
C++
/*
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* Copyright (C) 2014, 2015 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 "DFGStaticExecutionCountEstimationPhase.h"
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#if ENABLE(DFG_JIT)
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#include "DFGGraph.h"
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#include "DFGNaturalLoops.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 StaticExecutionCountEstimationPhase : public Phase {
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public:
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StaticExecutionCountEstimationPhase(Graph& graph)
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: Phase(graph, "static execution count estimation")
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{
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}
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bool run()
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{
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m_graph.ensureCPSNaturalLoops();
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// Estimate basic block execution counts based on loop depth.
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for (BlockIndex 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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block->executionCount = pow(10, m_graph.m_cpsNaturalLoops->loopDepth(block));
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}
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// Estimate branch weights based on execution counts. This isn't quite correct. It'll
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// assume that each block's conditional successor only has that block as its
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// predecessor.
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for (BlockIndex 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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Node* terminal = block->terminal();
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switch (terminal->op()) {
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case Branch: {
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BranchData* data = terminal->branchData();
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applyCounts(data->taken);
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applyCounts(data->notTaken);
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break;
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}
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case Switch: {
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SwitchData* data = terminal->switchData();
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for (unsigned i = data->cases.size(); i--;)
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applyCounts(data->cases[i].target);
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applyCounts(data->fallThrough);
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break;
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}
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case EntrySwitch: {
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DFG_CRASH(m_graph, terminal, "Unexpected EntrySwitch in CPS form.");
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break;
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}
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default:
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break;
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}
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}
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return true;
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}
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private:
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void applyCounts(BranchTarget& target)
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{
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target.count = target.block->executionCount;
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}
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};
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bool performStaticExecutionCountEstimation(Graph& graph)
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{
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return runPhase<StaticExecutionCountEstimationPhase>(graph);
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}
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} } // namespace JSC::DFG
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#endif // ENABLE(DFG_JIT)
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