[clang] [WebKit checkers] Treat function pointers with "Singleton" suffix as singleton. (PR #158012)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Ryosuke Niwa (rniwa)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/158012.diff


4 Files Affected:

- (modified) clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp (+5) 
- (modified) clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp (+1-1) 
- (modified) clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h (+2-1) 
- (modified) clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm (+11) 


``````````diff
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
index 478bd85177143..e851d0834226c 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
@@ -153,6 +153,11 @@ bool tryToFindPtrOrigin(
         if (Name == "__builtin___CFStringMakeConstantString" ||
             Name == "NSClassFromString")
           return callback(E, true);
+      } else if (auto* CalleeE = call->getCallee()) {
+        if (auto *E = dyn_cast<DeclRefExpr>(CalleeE->IgnoreParenCasts())) {
+          if (isSingleton(E->getFoundDecl()))
+            return callback(E, true);
+        }
       }
     }
     if (auto *ObjCMsgExpr = dyn_cast<ObjCMessageExpr>(E)) {
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
index 36c12582a5787..e86859a6aa56d 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
@@ -479,7 +479,7 @@ bool isTrivialBuiltinFunction(const FunctionDecl *F) {
          Name.starts_with("os_log") || Name.starts_with("_os_log");
 }
 
-bool isSingleton(const FunctionDecl *F) {
+bool isSingleton(const NamedDecl *F) {
   assert(F);
   // FIXME: check # of params == 1
   if (auto *MethodDecl = dyn_cast<CXXMethodDecl>(F)) {
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h
index 3c9560cb8059b..d2095d07e1434 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h
@@ -21,6 +21,7 @@ class CXXMethodDecl;
 class CXXRecordDecl;
 class Decl;
 class FunctionDecl;
+class NamedDecl;
 class QualType;
 class RecordType;
 class Stmt;
@@ -156,7 +157,7 @@ bool isPtrConversion(const FunctionDecl *F);
 bool isTrivialBuiltinFunction(const FunctionDecl *F);
 
 /// \returns true if \p F is a static singleton function.
-bool isSingleton(const FunctionDecl *F);
+bool isSingleton(const NamedDecl *F);
 
 /// An inter-procedural analysis facility that detects functions with "trivial"
 /// behavior with respect to reference counting, such as simple field getters.
diff --git a/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm b/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm
index c69113c48806d..b9010d2be9162 100644
--- a/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm
+++ b/clang/test/Analysis/Checkers/WebKit/unretained-call-args.mm
@@ -438,6 +438,17 @@ void use_const_local() {
 
 } // namespace const_global
 
+namespace var_decl_ref_singleton {
+
+static Class initSomeObject() { return nil; }
+static Class (*getSomeObjectClassSingleton)() = initSomeObject;
+
+bool foo(NSString *obj) {
+  return [obj isKindOfClass:getSomeObjectClassSingleton()];
+}
+
+} // namespace var_decl_ref_singleton
+
 @interface TestObject : NSObject
 - (void)doWork:(NSString *)msg, ...;
 - (void)doWorkOnSelf;

``````````

</details>


https://github.com/llvm/llvm-project/pull/158012