118 lines
4.4 KiB
C++
118 lines
4.4 KiB
C++
/*
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* Copyright (C) 2011, 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 "DFGVirtualRegisterAllocationPhase.h"
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#if ENABLE(DFG_JIT)
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#include "DFGGraph.h"
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#include "DFGScoreBoard.h"
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#include "JSCJSValueInlines.h"
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namespace JSC { namespace DFG {
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class VirtualRegisterAllocationPhase : public Phase {
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public:
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VirtualRegisterAllocationPhase(Graph& graph)
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: Phase(graph, "virtual register allocation")
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{
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}
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bool run()
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{
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DFG_ASSERT(m_graph, nullptr, m_graph.m_form == ThreadedCPS);
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ScoreBoard scoreBoard(m_graph.m_nextMachineLocal);
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scoreBoard.assertClear();
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for (size_t 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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if (!block->isReachable)
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continue;
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if (ASSERT_ENABLED) {
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// Force usage of highest-numbered virtual registers.
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scoreBoard.sortFree();
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}
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for (auto* node : *block) {
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if (!node->shouldGenerate())
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continue;
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switch (node->op()) {
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case Phi:
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case Flush:
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case PhantomLocal:
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continue;
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case GetLocal:
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ASSERT(!node->child1()->hasResult());
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break;
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default:
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break;
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}
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// First, call use on all of the current node's children, then
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// allocate a VirtualRegister for this node. We do so in this
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// order so that if a child is on its last use, and a
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// VirtualRegister is freed, then it may be reused for node.
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if (node->flags() & NodeHasVarArgs) {
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for (unsigned childIdx = node->firstChild(); childIdx < node->firstChild() + node->numChildren(); childIdx++)
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scoreBoard.useIfHasResult(m_graph.m_varArgChildren[childIdx]);
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} else {
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scoreBoard.useIfHasResult(node->child1());
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scoreBoard.useIfHasResult(node->child2());
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scoreBoard.useIfHasResult(node->child3());
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}
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if (!node->hasResult())
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continue;
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VirtualRegister virtualRegister = scoreBoard.allocate();
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node->setVirtualRegister(virtualRegister);
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// 'mustGenerate' nodes have their useCount artificially elevated,
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// call use now to account for this.
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if (node->mustGenerate())
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scoreBoard.use(node);
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}
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scoreBoard.assertClear();
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}
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// Record the number of virtual registers we're using. This is used by calls
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// to figure out where to put the parameters.
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m_graph.m_nextMachineLocal = scoreBoard.highWatermark();
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return true;
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}
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};
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bool performVirtualRegisterAllocation(Graph& graph)
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{
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return runPhase<VirtualRegisterAllocationPhase>(graph);
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}
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} } // namespace JSC::DFG
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#endif // ENABLE(DFG_JIT)
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