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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 "DFGArithNodeFlagsInferencePhase.h"
#if ENABLE(DFG_JIT)
#include "DFGGraph.h"
#include "DFGPhase.h"
namespace JSC { namespace DFG {
class ArithNodeFlagsInferencePhase : public Phase {
public:
ArithNodeFlagsInferencePhase(Graph& graph)
: Phase(graph, "arithmetic node flags inference")
{
}
void run()
{
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
m_count = 0;
#endif
do {
m_changed = false;
// Up here we start with a backward pass because we suspect that to be
// more profitable.
propagateBackward();
if (!m_changed)
break;
m_changed = false;
propagateForward();
} while (m_changed);
}
private:
bool isNotNegZero(NodeIndex nodeIndex)
{
if (!m_graph.isNumberConstant(nodeIndex))
return false;
double value = m_graph.valueOfNumberConstant(nodeIndex);
return !value && 1.0 / value < 0.0;
}
bool isNotZero(NodeIndex nodeIndex)
{
if (!m_graph.isNumberConstant(nodeIndex))
return false;
return !!m_graph.valueOfNumberConstant(nodeIndex);
}
void propagate(Node& node)
{
if (!node.shouldGenerate())
return;
NodeType op = static_cast<NodeType>(node.op);
NodeFlags flags = node.flags;
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
dataLog(" %s @%u: %s ", Graph::opName(op), m_compileIndex, arithNodeFlagsAsString(flags));
#endif
flags &= NodeUsedAsMask;
bool changed = false;
switch (op) {
case ValueToInt32:
case BitAnd:
case BitOr:
case BitXor:
case BitLShift:
case BitRShift:
case BitURShift: {
// These operations are perfectly happy with truncated integers,
// so we don't want to propagate anything.
break;
}
case UInt32ToNumber: {
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags);
break;
}
case ArithAdd:
case ValueAdd: {
if (isNotNegZero(node.child1().index()) || isNotNegZero(node.child2().index()))
flags &= ~NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags);
changed |= m_graph[node.child2()].mergeArithNodeFlags(flags);
break;
}
case ArithSub: {
if (isNotZero(node.child1().index()) || isNotZero(node.child2().index()))
flags &= ~NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags);
changed |= m_graph[node.child2()].mergeArithNodeFlags(flags);
break;
}
case ArithNegate: {
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags);
break;
}
case ArithMul:
case ArithDiv: {
// As soon as a multiply happens, we can easily end up in the part
// of the double domain where the point at which you do truncation
// can change the outcome. So, ArithMul always checks for overflow
// no matter what, and always forces its inputs to check as well.
flags |= NodeUsedAsNumber | NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags);
changed |= m_graph[node.child2()].mergeArithNodeFlags(flags);
break;
}
case ArithMin:
case ArithMax: {
flags |= NodeUsedAsNumber;
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags);
changed |= m_graph[node.child2()].mergeArithNodeFlags(flags);
break;
}
case ArithAbs: {
flags &= ~NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags);
break;
}
case PutByVal: {
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags | NodeUsedAsNumber | NodeNeedsNegZero);
changed |= m_graph[node.child2()].mergeArithNodeFlags(flags | NodeUsedAsNumber);
changed |= m_graph[node.child3()].mergeArithNodeFlags(flags | NodeUsedAsNumber | NodeNeedsNegZero);
break;
}
case GetByVal: {
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags | NodeUsedAsNumber | NodeNeedsNegZero);
changed |= m_graph[node.child2()].mergeArithNodeFlags(flags | NodeUsedAsNumber);
break;
}
default:
flags |= NodeUsedAsNumber | NodeNeedsNegZero;
if (node.flags & NodeHasVarArgs) {
for (unsigned childIdx = node.firstChild(); childIdx < node.firstChild() + node.numChildren(); childIdx++)
changed |= m_graph[m_graph.m_varArgChildren[childIdx]].mergeArithNodeFlags(flags);
} else {
if (!node.child1())
break;
changed |= m_graph[node.child1()].mergeArithNodeFlags(flags);
if (!node.child2())
break;
changed |= m_graph[node.child2()].mergeArithNodeFlags(flags);
if (!node.child3())
break;
changed |= m_graph[node.child3()].mergeArithNodeFlags(flags);
}
break;
}
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
dataLog("%s\n", changed ? "CHANGED" : "");
#endif
m_changed |= changed;
}
void propagateForward()
{
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
dataLog("Propagating arithmetic node flags forward [%u]\n", ++m_count);
#endif
for (m_compileIndex = 0; m_compileIndex < m_graph.size(); ++m_compileIndex)
propagate(m_graph[m_compileIndex]);
}
void propagateBackward()
{
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
dataLog("Propagating arithmetic node flags backward [%u]\n", ++m_count);
#endif
for (m_compileIndex = m_graph.size(); m_compileIndex-- > 0;)
propagate(m_graph[m_compileIndex]);
}
NodeIndex m_compileIndex;
bool m_changed;
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
unsigned m_count;
#endif
};
void performArithNodeFlagsInference(Graph& graph)
{
runPhase<ArithNodeFlagsInferencePhase>(graph);
}
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)
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