[clang] [NFC] explicitly check if ParentMap contains key #121736
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The implementation of ParentMap assumes that the key is absent if it is mapped to nullptr. This breaks when trying to store a tuple as the value type. Remove this assumption by explicit uses of `contains()` and `erase()`.
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@llvm/pr-subscribers-clang Author: Sameer Sahasrabuddhe (ssahasra) ChangesThe implementation of ParentMap assumes that the key is absent if it is mapped to nullptr. This breaks when trying to store a tuple as the value type. Remove this assumption by explicit uses of Full diff: https://github.com/llvm/llvm-project/pull/121736.diff 1 Files Affected:
diff --git a/clang/lib/AST/ParentMap.cpp b/clang/lib/AST/ParentMap.cpp
index fd749b02b758c9..ada7b19487a782 100644
--- a/clang/lib/AST/ParentMap.cpp
+++ b/clang/lib/AST/ParentMap.cpp
@@ -34,13 +34,13 @@ static void BuildParentMap(MapTy& M, Stmt* S,
case Stmt::PseudoObjectExprClass: {
PseudoObjectExpr *POE = cast<PseudoObjectExpr>(S);
- if (OVMode == OV_Opaque && M[POE->getSyntacticForm()])
+ if (OVMode == OV_Opaque && M.contains(POE->getSyntacticForm()))
break;
// If we are rebuilding the map, clear out any existing state.
- if (M[POE->getSyntacticForm()])
+ if (M.contains(POE->getSyntacticForm()))
for (Stmt *SubStmt : S->children())
- M[SubStmt] = nullptr;
+ M.erase(SubStmt);
M[POE->getSyntacticForm()] = S;
BuildParentMap(M, POE->getSyntacticForm(), OV_Transparent);
@@ -78,7 +78,7 @@ static void BuildParentMap(MapTy& M, Stmt* S,
// The right thing to do is to give the OpaqueValueExpr its syntactic
// parent, then not reassign that when traversing the semantic expressions.
OpaqueValueExpr *OVE = cast<OpaqueValueExpr>(S);
- if (OVMode == OV_Transparent || !M[OVE->getSourceExpr()]) {
+ if (OVMode == OV_Transparent || !M.contains(OVE->getSourceExpr())) {
M[OVE->getSourceExpr()] = S;
BuildParentMap(M, OVE->getSourceExpr(), OV_Transparent);
}
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ssahasra
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jayfoad
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Jan 6, 2025
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No objections, just a couple of ideas for improvements. I have no idea if ParentMap lookups are on any kind of hot path.
clang/lib/AST/ParentMap.cpp
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| PseudoObjectExpr *POE = cast<PseudoObjectExpr>(S); | ||
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| if (OVMode == OV_Opaque && M[POE->getSyntacticForm()]) | ||
| if (OVMode == OV_Opaque && M.contains(POE->getSyntacticForm())) |
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Could put this and the next if inside one big if (M.contains) check to avoid a duplicated map lookup.
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Fixed with try_emplace() to avoid the second lookup as well, which inserts when the key is already present.
clang/lib/AST/ParentMap.cpp
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| if (OVMode == OV_Transparent || !M.contains(OVE->getSourceExpr())) { | ||
| M[OVE->getSourceExpr()] = S; |
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Could use M.find to avoid the duplicated lookup here?
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Fixed with try_emplace() to avoid the second lookup as well, which inserts when the key is already present.
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arsenm
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Jan 7, 2025
jayfoad
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Jan 7, 2025
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/52/builds/5076 Here is the relevant piece of the build log for the reference |
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Jan 8, 2025
This fixes a bug that slipped into #121736.
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The implementation of ParentMap assumes that the key is absent if it is mapped to nullptr. This breaks when trying to store a tuple as the value type. Remove this assumption by explicit uses of
contains()anderase().