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/*
* Copyright (C) 2011, 2013 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "DFGVirtualRegisterAllocationPhase.h"
#if ENABLE(DFG_JIT)
#include "DFGGraph.h"
#include "DFGScoreBoard.h"
#include "JSCInlines.h"
#include "StackAlignment.h"
#include <wtf/StdLibExtras.h>
namespace JSC { namespace DFG {
class VirtualRegisterAllocationPhase : public Phase {
public:
VirtualRegisterAllocationPhase(Graph& graph)
: Phase(graph, "virtual register allocation")
{
}
bool run()
{
DFG_ASSERT(m_graph, nullptr, m_graph.m_form == ThreadedCPS);
ScoreBoard scoreBoard(m_graph.m_nextMachineLocal);
scoreBoard.assertClear();
for (size_t blockIndex = 0; blockIndex < m_graph.numBlocks(); ++blockIndex) {
BasicBlock* block = m_graph.block(blockIndex);
if (!block)
continue;
if (!block->isReachable)
continue;
if (!ASSERT_DISABLED) {
// Force usage of highest-numbered virtual registers.
scoreBoard.sortFree();
}
for (size_t indexInBlock = 0; indexInBlock < block->size(); ++indexInBlock) {
Node* node = block->at(indexInBlock);
if (!node->shouldGenerate())
continue;
switch (node->op()) {
case Phi:
case Flush:
case PhantomLocal:
continue;
case GetLocal:
ASSERT(!node->child1()->hasResult());
break;
default:
break;
}
// First, call use on all of the current node's children, then
// allocate a VirtualRegister for this node. We do so in this
// order so that if a child is on its last use, and a
// VirtualRegister is freed, then it may be reused for node.
if (node->flags() & NodeHasVarArgs) {
for (unsigned childIdx = node->firstChild(); childIdx < node->firstChild() + node->numChildren(); childIdx++)
scoreBoard.useIfHasResult(m_graph.m_varArgChildren[childIdx]);
} else {
scoreBoard.useIfHasResult(node->child1());
scoreBoard.useIfHasResult(node->child2());
scoreBoard.useIfHasResult(node->child3());
}
if (!node->hasResult())
continue;
VirtualRegister virtualRegister = scoreBoard.allocate();
node->setVirtualRegister(virtualRegister);
// 'mustGenerate' nodes have their useCount artificially elevated,
// call use now to account for this.
if (node->mustGenerate())
scoreBoard.use(node);
}
scoreBoard.assertClear();
}
// Record the number of virtual registers we're using. This is used by calls
// to figure out where to put the parameters.
m_graph.m_nextMachineLocal = scoreBoard.highWatermark();
return true;
}
};
bool performVirtualRegisterAllocation(Graph& graph)
{
SamplingRegion samplingRegion("DFG Virtual Register Allocation Phase");
return runPhase<VirtualRegisterAllocationPhase>(graph);
}
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)
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