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Fix bad join order in SsaDefinitionsImpl::reachesEndOfBlock.

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Taus Brock-Nannestad
2019-07-03 16:26:10 +02:00
parent 315dcb8720
commit 11ceaf3e3c
1 changed files with 9 additions and 6 deletions
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15
python/ql/src/semmle/dataflow/SsaCompute.qll
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@@ -267,6 +267,12 @@ private cached module SsaComputeImpl {
cached module SsaDefinitionsImpl {
pragma [noinline]
private predicate reachesEndOfBlockRec(SsaSourceVariable v, BasicBlock defbb, int defindex, BasicBlock b) {
exists(BasicBlock idom | reachesEndOfBlock(v, defbb, defindex, idom) |
idom = b.getImmediateDominator()
)
}
/**
* The SSA definition of `v` at `def` reaches the end of a basic block `b`, at
* which point it is still live, without crossing another SSA definition of `v`.
@@ -277,13 +283,10 @@ private cached module SsaComputeImpl {
(
defbb = b and SsaComputeImpl::ssaDefReachesRank(v, defbb, defindex, SsaComputeImpl::lastRank(v, b))
or
exists(BasicBlock idom |
idom = b.getImmediateDominator() and
// It is sufficient to traverse the dominator graph, cf. discussion above.
reachesEndOfBlock(v, defbb, defindex, idom) and
not SsaComputeImpl::ssaDef(v, b)
// It is sufficient to traverse the dominator graph, cf. discussion above.
reachesEndOfBlockRec(v, defbb, defindex, b) and
not SsaComputeImpl::ssaDef(v, b)
)
)
}
/**