[PATCH] D151325: [analyzer] Differentiate lifetime extended temporaries

[Gábor Horváth via Phabricator via cfe-commits]

xazax.hun accepted this revision.
xazax.hun added inline comments.


================
Comment at: clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h:1282
+  LLVM_ATTRIBUTE_RETURNS_NONNULL
+  const Expr *getExpr() const { return Ex; }
+  LLVM_ATTRIBUTE_RETURNS_NONNULL
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tomasz-kaminski-sonarsource wrote:
> xazax.hun wrote:
> > Do we actually need this `Expr` in the memory region?
> Yes they are needed for region identification, as one variable my be lifetime extending multiple temporary.
> For illustration consider following example from test:
> ```
>   auto const& viaReference = RefAggregate{10, Composite{}}; // extends `int`, `Composite`, and `RefAggregate`
>   clang_analyzer_dump(viaReference);    // expected-warning-re {{&lifetime_extended_object{RefAggregate, viaReference, S{{[0-9]+}}} }}
>   clang_analyzer_dump(viaReference.rx); // expected-warning-re {{&lifetime_extended_object{int, viaReference, S{{[0-9]+}}} }}
>   clang_analyzer_dump(viaReference.ry); // expected-warning-re {{&lifetime_extended_object{Composite, viaReference, S{{[0-9]+}}} }}
> ```
> `viaReference` declaration is extending 3 temporaries, and they get identified by expression.
Ah, OK. Makes sense, thanks!


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https://reviews.llvm.org/D151325