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/*
* Copyright (C) 2011 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"
namespace JSC { namespace DFG {
class VirtualRegisterAllocationPhase : public Phase {
public:
VirtualRegisterAllocationPhase(Graph& graph)
: Phase(graph, "virtual register allocation")
{
}
void run()
{
#if DFG_ENABLE(DEBUG_VERBOSE)
dataLog("Preserved vars: ");
m_graph.m_preservedVars.dump(WTF::dataFile());
dataLog("\n");
#endif
ScoreBoard scoreBoard(m_graph, m_graph.m_preservedVars);
unsigned sizeExcludingPhiNodes = m_graph.m_blocks.last()->end;
for (size_t i = 0; i < sizeExcludingPhiNodes; ++i) {
Node& node = m_graph[i];
if (!node.shouldGenerate())
continue;
// GetLocal nodes are effectively phi nodes in the graph, referencing
// results from prior blocks.
if (node.op != GetLocal) {
// 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.op & NodeHasVarArgs) {
for (unsigned childIdx = node.firstChild(); childIdx < node.firstChild() + node.numChildren(); childIdx++)
scoreBoard.use(m_graph.m_varArgChildren[childIdx]);
} else {
scoreBoard.use(node.child1());
scoreBoard.use(node.child2());
scoreBoard.use(node.child3());
}
}
if (!node.hasResult())
continue;
node.setVirtualRegister(scoreBoard.allocate());
// 'mustGenerate' nodes have their useCount artificially elevated,
// call use now to account for this.
if (node.mustGenerate())
scoreBoard.use(i);
}
// 'm_numCalleeRegisters' is the number of locals and temporaries allocated
// for the function (and checked for on entry). Since we perform a new and
// different allocation of temporaries, more registers may now be required.
unsigned calleeRegisters = scoreBoard.highWatermark() + m_graph.m_parameterSlots;
if ((unsigned)codeBlock()->m_numCalleeRegisters < calleeRegisters)
codeBlock()->m_numCalleeRegisters = calleeRegisters;
#if DFG_ENABLE(DEBUG_VERBOSE)
dataLog("Num callee registers: %u\n", calleeRegisters);
#endif
}
};
void performVirtualRegisterAllocation(Graph& graph)
{
runPhase<VirtualRegisterAllocationPhase>(graph);
}
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)
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