[clang][analyzer] Handle CXXParenInitListExpr alongside InitListExpr by fangyi-zhou · Pull Request #136041 · llvm/llvm-project (original) (raw)

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As reported in #135665, C++20 parenthesis initializer list expressions are not handled correctly and were causing crashes. This commit attempts to fix the issue by handing parenthesis initializer lists along side existing initializer lists.

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@llvm/pr-subscribers-clang-static-analyzer-1

@llvm/pr-subscribers-clang

Author: Fangyi Zhou (fangyi-zhou)

Changes

Full diff: https://github.com/llvm/llvm-project/pull/136041.diff

3 Files Affected:

(modified) clang/lib/StaticAnalyzer/Checkers/DynamicTypePropagation.cpp (+6-4)
(modified) clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp (+7-4)
(added) clang/test/Analysis/PR135665.cpp (+19)

diff --git a/clang/lib/StaticAnalyzer/Checkers/DynamicTypePropagation.cpp b/clang/lib/StaticAnalyzer/Checkers/DynamicTypePropagation.cpp index a0bf776b11f53..6fad0601e87ca 100644 --- a/clang/lib/StaticAnalyzer/Checkers/DynamicTypePropagation.cpp +++ b/clang/lib/StaticAnalyzer/Checkers/DynamicTypePropagation.cpp @@ -379,10 +379,12 @@ void DynamicTypePropagation::checkPostCall(const CallEvent &Call, // aggregates, and in such case no top-frame constructor will be called. // Figure out if we need to do anything in this case. // FIXME: Instead of relying on the ParentMap, we should have the

   // trigger-statement (InitListExpr in this case) available in this

   // callback, ideally as part of CallEvent.

```
   if (isa_and_nonnull<InitListExpr>(
```

           LCtx->getParentMap().getParent(Ctor->getOriginExpr())))

   // trigger-statement (InitListExpr or CXXParenListInitExpr in this case)

   // available in this callback, ideally as part of CallEvent.

```
   const Stmt *Parent =
```

       LCtx->getParentMap().getParent(Ctor->getOriginExpr());

   if (isa_and_nonnull<InitListExpr>(Parent) ||

       isa_and_nonnull<CXXParenListInitExpr>(Parent))
     return;

   recordFixedType(Target, cast<CXXConstructorDecl>(LCtx->getDecl()), C);

diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp index 7e878f922a939..914859861b948 100644 --- a/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp +++ b/clang/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp @@ -644,9 +644,11 @@ void ExprEngine::handleConstructor(const Expr *E, // FIXME: For now this code essentially bails out. We need to find the // correct target region and set it. // FIXME: Instead of relying on the ParentMap, we should have the

// trigger-statement (InitListExpr in this case) passed down from CFG or
// otherwise always available during construction.
if (isa_and_nonnull(LCtx->getParentMap().getParent(E))) {

// trigger-statement (InitListExpr or CXXParenListInitExpr in this case)
// passed down from CFG or otherwise always available during construction.
if (isa_and_nonnull(LCtx->getParentMap().getParent(E)) ||

   isa_and_nonnull<CXXParenListInitExpr>(

       LCtx->getParentMap().getParent(E))) {
 MemRegionManager &MRMgr = getSValBuilder().getRegionManager();
 Target = loc::MemRegionVal(MRMgr.getCXXTempObjectRegion(E, LCtx));
 CallOpts.IsCtorOrDtorWithImproperlyModeledTargetRegion = true;

@@ -1017,7 +1019,8 @@ void ExprEngine::VisitCXXNewExpr(const CXXNewExpr *CNE, ExplodedNode *Pred, // values are properly placed inside the required region, however if an // initializer list is used, this doesn't happen automatically. auto *Init = CNE->getInitializer();

 bool isInitList = isa_and_nonnull<InitListExpr>(Init);

 bool isInitList = isa_and_nonnull<InitListExpr>(Init) ||

                   isa_and_nonnull<CXXParenListInitExpr>(Init);

 QualType ObjTy =
     isInitList ? Init->getType() : CNE->getType()->getPointeeType();

diff --git a/clang/test/Analysis/PR135665.cpp b/clang/test/Analysis/PR135665.cpp new file mode 100644 index 0000000000000..124b8c9b97b04 --- /dev/null +++ b/clang/test/Analysis/PR135665.cpp @@ -0,0 +1,19 @@ +// RUN: %clang_analyze_cc1 -std=c++20 -analyzer-checker=core -verify %s + +// expected-no-diagnostics + +template<typename... F> +struct overload : public F... +{

using F::operator()...; +};
+template<typename... F> +overload(F&&...) -> overload<F...>;
+int main() +{
const auto l = overload([](const int* i) {});
return 0; +}

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Thank you for your patch! Please add a release note in clang/docs/ReleaseNotes.rst .

As reported in llvm#135665, C++20 parenthesis initializer list expressions are not handled correctly and were causing crashes. This commit attempts to fix the issue by handing parenthesis initializer lists along side existing initializer lists.

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LGTM, thanks. FYI we usually ping once a week.

@fangyi-zhou Congratulations on having your first Pull Request (PR) merged into the LLVM Project!

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FYI we usually ping once a week.

Oh, I see. IIUC @ llvm/pr-subscribers-clang-static-analyzer-1 is also a ping, which I didn't know.

Ah, I see now your perspective.
Yes, any PRs tagged with the CSA tag will hit our inboxes.

IanWood1 pushed a commit to IanWood1/llvm-project that referenced this pull request

May 6, 2025

…lvm#136041)

Fixes llvm#135665.

IanWood1 pushed a commit to IanWood1/llvm-project that referenced this pull request

May 6, 2025

…lvm#136041)

Fixes llvm#135665.

IanWood1 pushed a commit to IanWood1/llvm-project that referenced this pull request

May 6, 2025

…lvm#136041)

Fixes llvm#135665.