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Merge pull request #10818 from github/mathiasvp/fix-join-in-ssa-internals

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C++: Fix join in `SsaInternals`
This commit is contained in:
Robert Marsh
2022-10-17 13:36:32 -04:00
committed by GitHub
parent 5cd6dafe27 134cc6291c
commit 2f0c7729ff
1 changed files with 16 additions and 4 deletions
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20
cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/SsaInternals.qll
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@@ -371,6 +371,21 @@ predicate ssaFlow(Node nodeFrom, Node nodeTo) {
)
}
/**
* Holds if `use` is a use of `sv` and is a next adjacent use of `phi` in
* index `i1` in basic block `bb1`.
*
* This predicate exists to prevent an early join of `adjacentDefRead` with `definesAt`.
*/
pragma[nomagic]
private predicate fromPhiNodeToUse(PhiNode phi, SourceVariable sv, IRBlock bb1, int i1, UseOrPhi use) {
exists(IRBlock bb2, int i2 |
use.asDefOrUse().hasIndexInBlock(bb2, i2, sv) and
adjacentDefRead(pragma[only_bind_into](phi), pragma[only_bind_into](bb1),
pragma[only_bind_into](i1), pragma[only_bind_into](bb2), pragma[only_bind_into](i2))
)
}
/** Holds if `nodeTo` receives flow from the phi node `nodeFrom`. */
predicate fromPhiNode(SsaPhiNode nodeFrom, Node nodeTo) {
exists(PhiNode phi, SourceVariable sv, IRBlock bb1, int i1, UseOrPhi use |
@@ -378,10 +393,7 @@ predicate fromPhiNode(SsaPhiNode nodeFrom, Node nodeTo) {
phi.definesAt(sv, bb1, i1) and
useToNode(use, nodeTo)
|
exists(IRBlock bb2, int i2 |
use.asDefOrUse().hasIndexInBlock(bb2, i2, sv) and
adjacentDefRead(phi, bb1, i1, bb2, i2)
)
fromPhiNodeToUse(phi, sv, bb1, i1, use)
or
exists(PhiNode phiTo |
lastRefRedef(phi, _, _, phiTo) and