[clang] [Clang] Prevent null pointer dereference in target attribute mangling (PR #94228)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-codegen

Author: None (smanna12)

<details>
<summary>Changes</summary>

This patch adds an assert in getMangledNameImpl() to ensure that the expected attributes (TargetAttr, TargetVersionAttr, and TargetClonesAttr) are checked for NULL value before being used by appendAttributeMangling().

---
Full diff: https://github.com/llvm/llvm-project/pull/94228.diff


1 Files Affected:

- (modified) clang/lib/CodeGen/CodeGenModule.cpp (+3) 


``````````diff
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index c2314c3a57d33..7541817e41e86 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1853,18 +1853,21 @@ static std::string getMangledNameImpl(CodeGenModule &CGM, GlobalDecl GD,
         break;
       case MultiVersionKind::Target: {
         auto *Attr = FD->getAttr<TargetAttr>();
+        assert(Attr && "Expected TargetAttr to be present for attribute mangling");
         const ABIInfo &Info = CGM.getTargetCodeGenInfo().getABIInfo();
         Info.appendAttributeMangling(Attr, Out);
         break;
       }
       case MultiVersionKind::TargetVersion: {
         auto *Attr = FD->getAttr<TargetVersionAttr>();
+        assert(Attr && "Expected TargetVersionAttr to be present for attribute mangling");
         const ABIInfo &Info = CGM.getTargetCodeGenInfo().getABIInfo();
         Info.appendAttributeMangling(Attr, Out);
         break;
       }
       case MultiVersionKind::TargetClones: {
         auto *Attr = FD->getAttr<TargetClonesAttr>();
+        assert(Attr && "Expected TargetClonesAttr to be present for attribute mangling");
         unsigned Index = GD.getMultiVersionIndex();
         const ABIInfo &Info = CGM.getTargetCodeGenInfo().getABIInfo();
         Info.appendAttributeMangling(Attr, Index, Out);

``````````

</details>


https://github.com/llvm/llvm-project/pull/94228