[clang] [analyzer] Support C++23 static operator calls (PR #84972)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

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

Author: Balazs Benics (steakhal)

<details>
<summary>Changes</summary>

Made by following:
https://github.com/llvm/llvm-project/pull/83585#issuecomment-1980340866

Thanks for the details Tomek!

---
Full diff: https://github.com/llvm/llvm-project/pull/84972.diff


5 Files Affected:

- (modified) clang/docs/ReleaseNotes.rst (+2) 
- (modified) clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h (+55) 
- (modified) clang/lib/StaticAnalyzer/Core/CallEvent.cpp (+4-1) 
- (modified) clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp (+1) 
- (added) clang/test/Analysis/cxx23-static-operator.cpp (+16) 


``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e14c92eae0afe1..7629707c122470 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -473,6 +473,8 @@ libclang
 Static Analyzer
 ---------------
 
+- Support C++23 static operator calls.
+
 New features
 ^^^^^^^^^^^^
 
diff --git a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h
index 0d36587484bf9c..be6d713f9f55fb 100644
--- a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h
+++ b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h
@@ -59,6 +59,7 @@ namespace ento {
 
 enum CallEventKind {
   CE_Function,
+  CE_CXXStaticOperator,
   CE_CXXMember,
   CE_CXXMemberOperator,
   CE_CXXDestructor,
@@ -709,6 +710,60 @@ class CXXInstanceCall : public AnyFunctionCall {
   }
 };
 
+/// Represents a static C++ operator call.
+///
+/// "A" in this example.
+/// However, "B" and "C" are represented by SimpleFunctionCall.
+/// \code
+///   struct S {
+///     int pad;
+///     static void operator()(int x, int y);
+///   };
+///   S s{10};
+///   void (*fptr)(int, int) = &S::operator();
+///
+///   s(1, 2);  // A
+///   S::operator()(1, 2);  // B
+///   fptr(1, 2); // C
+/// \endcode
+class CXXStaticOperatorCall : public SimpleFunctionCall {
+  friend class CallEventManager;
+
+protected:
+  CXXStaticOperatorCall(const CallExpr *CE, ProgramStateRef St,
+                        const LocationContext *LCtx,
+                        CFGBlock::ConstCFGElementRef ElemRef)
+      : SimpleFunctionCall(CE, St, LCtx, ElemRef) {}
+  CXXStaticOperatorCall(const CXXStaticOperatorCall &Other) = default;
+
+  void cloneTo(void *Dest) const override {
+    new (Dest) CXXStaticOperatorCall(*this);
+  }
+
+public:
+  const CXXOperatorCallExpr *getOriginExpr() const override {
+    return cast<CXXOperatorCallExpr>(SimpleFunctionCall::getOriginExpr());
+  }
+
+  unsigned getNumArgs() const override {
+    // Ignore the implicit object parameter.
+    assert(getOriginExpr()->getNumArgs() > 0);
+    return getOriginExpr()->getNumArgs() - 1;
+  }
+
+  const Expr *getArgExpr(unsigned Index) const override {
+    // Ignore the implicit object parameter.
+    return getOriginExpr()->getArg(Index + 1);
+  }
+
+  Kind getKind() const override { return CE_CXXStaticOperator; }
+  StringRef getKindAsString() const override { return "CXXStaticOperatorCall"; }
+
+  static bool classof(const CallEvent *CA) {
+    return CA->getKind() == CE_CXXStaticOperator;
+  }
+};
+
 /// Represents a non-static C++ member function call.
 ///
 /// Example: \c obj.fun()
diff --git a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
index bc14aea27f6736..0e317ec765ec09 100644
--- a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -1408,9 +1408,12 @@ CallEventManager::getSimpleCall(const CallExpr *CE, ProgramStateRef State,
 
   if (const auto *OpCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
     const FunctionDecl *DirectCallee = OpCE->getDirectCallee();
-    if (const auto *MD = dyn_cast<CXXMethodDecl>(DirectCallee))
+    if (const auto *MD = dyn_cast<CXXMethodDecl>(DirectCallee)) {
       if (MD->isImplicitObjectMemberFunction())
         return create<CXXMemberOperatorCall>(OpCE, State, LCtx, ElemRef);
+      if (MD->isStatic())
+        return create<CXXStaticOperatorCall>(OpCE, State, LCtx, ElemRef);
+    }
 
   } else if (CE->getCallee()->getType()->isBlockPointerType()) {
     return create<BlockCall>(CE, State, LCtx, ElemRef);
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
index 4755b6bfa6dc0a..9d3e4fc944fb7b 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
@@ -846,6 +846,7 @@ ExprEngine::mayInlineCallKind(const CallEvent &Call, const ExplodedNode *Pred,
   const StackFrameContext *CallerSFC = CurLC->getStackFrame();
   switch (Call.getKind()) {
   case CE_Function:
+  case CE_CXXStaticOperator:
   case CE_Block:
     break;
   case CE_CXXMember:
diff --git a/clang/test/Analysis/cxx23-static-operator.cpp b/clang/test/Analysis/cxx23-static-operator.cpp
new file mode 100644
index 00000000000000..3c541c336f417a
--- /dev/null
+++ b/clang/test/Analysis/cxx23-static-operator.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_analyze_cc1 -std=c++2b -verify %s \
+// RUN:   -analyzer-checker=core,debug.ExprInspection
+
+template <typename T> void clang_analyzer_dump(T);
+
+struct Adder {
+  int data;
+  static int operator()(int x, int y) {
+    return x + y;
+  }
+};
+
+void static_operator_call_inlines() {
+  Adder s{10};
+  clang_analyzer_dump(s(1, 2)); // expected-warning {{3 S32b}}
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/84972