================
@@ -270,34 +270,49 @@ void Sema::inferLifetimeBoundAttribute(FunctionDecl *FD) {
}
void Sema::inferLifetimeCaptureByAttribute(FunctionDecl *FD) {
- if (!FD)
+ auto *MD = dyn_cast_if_present<CXXMethodDecl>(FD);
+ if (!MD || !MD->getParent()->isInStdNamespace())
return;
- auto *MD = dyn_cast<CXXMethodDecl>(FD);
- if (!MD || !MD->getIdentifier() || !MD->getParent()->isInStdNamespace())
+ auto Annotate = [this](const FunctionDecl *MD) {
+ // Do not infer if any parameter is explicitly annotated.
+ for (ParmVarDecl *PVD : MD->parameters())
+ if (PVD->hasAttr<LifetimeCaptureByAttr>())
+ return;
+ for (ParmVarDecl *PVD : MD->parameters()) {
+ // Methods in standard containers that capture values typically accept
+ // reference-type parameters, e.g., `void push_back(const T& value)`.
+ // We only apply the lifetime_capture_by attribute to parameters of
+ // pointer-like reference types (`const T&`, `T&&`).
+ if (PVD->getType()->isReferenceType() &&
+ sema::isPointerLikeType(PVD->getType().getNonReferenceType())) {
+ int CaptureByThis[] = {LifetimeCaptureByAttr::THIS};
+ PVD->addAttr(
+ LifetimeCaptureByAttr::CreateImplicit(Context, CaptureByThis, 1));
+ }
+ }
+ };
+
+ if (!MD->getIdentifier()) {
+ static const llvm::StringSet<> MapLikeContainer{
+ "map",
+ "multimap",
+ "unordered_map",
+ "unordered_multimap",
+ };
+ // Infer for the map's operator []:
+ // std::map<string_view, ...> m;
+ // m[ReturnString(..)] = ...; // !dangling references in m.
+ if (MD->getOverloadedOperator() != OO_Subscript ||
+ !MapLikeContainer.contains(MD->getParent()->getName()))
+ return;
----------------
usx95 wrote:
nit: early returns complicates this. Maybe simplify like:
```cpp
if (MD->getOverloadedOperator() == OO_Subscript &&
MapLikeContainer.contains(MD->getParent()->getName()))
Annotate(MD);
return;
```
https://github.com/llvm/llvm-project/pull/118078
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