[clang] Fix an issue where we erroneously diagnose a `[[noreturn]]` function with `warn_suggest_noreturn_function` (PR #148695)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: None (term-est)

<details>
<summary>Changes</summary>

The following snippet,

```c++
#include &lt;cassert&gt;
#include &lt;stdexcept&gt;

[[noreturn]] void foo() { throw std::runtime_error("Why...?"); }

int main() {
    try {
        foo();
    } catch (std::runtime_error const&amp; ex) {
        (void)ex;
    }
}
```

is diagnosed with `error: function 'foo' could be declared with attribute 
'noreturn' [-Werror,-Wmissing-noreturn]` when compiled with clang_trunk using 
`-Werror=missing-noreturn` flag. See more at 
[godbolt](https://godbolt.org/z/5zMsev4as)


AST shows
```
| `-CXX11NoReturnAttr 0x1896e81eb00 &lt;line:2:20&gt; Inherited noreturn
|-FunctionDecl 0x1896e81ebd8 &lt;line:10:14, col:46&gt; col:19 used foo 'void 
()'
| |-CompoundStmt 0x1896e81ee20 &lt;col:25, col:46&gt;
| | `-CXXThrowExpr 0x1896e81ee08 &lt;col:27, col:43&gt; 'void'
| |   `-ImplicitCastExpr 0x1896e81edf0 &lt;col:33, col:43&gt; 'const char *' 
&lt;ArrayToPointerDecay&gt;
| |     `-ParenExpr 0x1896e81eda0 &lt;col:33, col:43&gt; 'const char[8]' lvalue
| |       `-StringLiteral 0x1896e81ed80 &lt;col:34&gt; 'const char[8]' lvalue 
"Why...?"
| |-CXX11NoReturnAttr 0x1896e81ec80 &lt;col:3&gt; noreturn
| `-InferredNoReturnAttr 0x1896e81ee38 &lt;&lt;invalid sloc&gt;&gt; Implicit
```

but the responsible code only checks for `NoReturnAttr`, adding a check for 
`CXX11NoReturnAttr` before emitting the diagnostic should fix this issue.

---
Full diff: https://github.com/llvm/llvm-project/pull/148695.diff


1 Files Affected:

- (modified) clang/lib/Sema/SemaDeclAttr.cpp (+1-1) 


``````````diff
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 099207727c8c8..6d0a5d71d49ff 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -1976,7 +1976,7 @@ void clang::inferNoReturnAttr(Sema &S, const Decl *D) {
       Diags.isIgnored(diag::warn_suggest_noreturn_function, FD->getLocation()))
     return;
 
-  if (!FD->hasAttr<NoReturnAttr>() && !FD->hasAttr<InferredNoReturnAttr>() &&
+  if (!FD->hasAttr<NoReturnAttr>() && !FD->hasAttr<CXX11NoReturnAttr>() && 
!FD->hasAttr<InferredNoReturnAttr>() &&
       isKnownToAlwaysThrow(FD)) {
     NonConstFD->addAttr(InferredNoReturnAttr::CreateImplicit(S.Context));
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/148695
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits