[clang] [analyzer] Fix crash on non-standard string function overloads (PR #180544)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-static-analyzer-1

@llvm/pr-subscribers-clang

Author: hanbeom (ParkHanbum)

<details>
<summary>Changes</summary>

Previously, C++ overloads like strcmp(char*, char) caused assertions. 
Now validates argument types match standard signatures.

Fixed: #<!-- -->180422


---
Full diff: https://github.com/llvm/llvm-project/pull/180544.diff


1 Files Affected:

- (modified) clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp (+16-1) 


``````````diff
diff --git a/clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
index 144411495f5a1..c3ca128ce5246 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
@@ -2801,8 +2801,23 @@ CStringChecker::FnCheck CStringChecker::identifyCall(const CallEvent &Call,
   }
 
   const FnCheck *Callback = Callbacks.lookup(Call);
-  if (Callback)
+  if (Callback) {
+    if (const IdentifierInfo *II = FD->getIdentifier()) {
+      StringRef Name = II->getName();
+      // Logic to confirm if the function has the same type as the known
+      // standard function. String comparison functions (like strcmp) are
+      // expected to take pointers as arguments.
+      // Signature: int strcmp(const char *s1, const char *s2);
+      // Requirement: Exactly 2 arguments, both must be pointers.
+      if (Name == "strcmp" || Name == "strcasecmp" || Name == "strcoll")
+        if (FD->getNumParams() != 2 ||
+            !FD->getParamDecl(0)->getType()->isPointerType() ||
+            !FD->getParamDecl(1)->getType()->isPointerType())
+          return nullptr;
+    }
+
     return *Callback;
+  }
 
   return nullptr;
 }

``````````

</details>


https://github.com/llvm/llvm-project/pull/180544