[clang-tools-extra] [clang-tidy]add new check `bugprone-compare-pointer-to-member-virtual-function` (PR #66055)

[via cfe-commits]

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@@ -0,0 +1,107 @@
+//===--- ComparePointerToMemberVirtualFunctionCheck.cpp - clang-tidy ------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "ComparePointerToMemberVirtualFunctionCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/ASTTypeTraits.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/OperationKinds.h"
+#include "clang/AST/Type.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/ASTMatchers/ASTMatchersMacros.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticIDs.h"
+#include "llvm/ADT/SmallVector.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::bugprone {
+
+namespace {
+
+AST_MATCHER(CXXMethodDecl, isVirtual) { return Node.isVirtual(); }
+
+static const char *const ErrorMsg =
+    "comparing a pointer to member virtual function with other pointer is "
+    "unspecified behavior, only compare it with a null-pointer constant for "
+    "equality.";
+    
+} // namespace
+
+void ComparePointerToMemberVirtualFunctionCheck::registerMatchers(
+    MatchFinder *Finder) {
+
+  auto DirectMemberVirtualFunctionPointer = unaryOperator(
+      allOf(hasOperatorName("&"),
+            hasUnaryOperand(declRefExpr(to(cxxMethodDecl(isVirtual()))))));
+  auto IndirectMemberPointer =
+      ignoringImpCasts(declRefExpr().bind("indirect_member_pointer"));
+
+  Finder->addMatcher(
+      binaryOperator(
+          allOf(hasAnyOperatorName("==", "!="),
+                hasEitherOperand(
+                    hasType(memberPointerType(pointee(functionType())))),
+                anyOf(hasEitherOperand(DirectMemberVirtualFunctionPointer),
+                      hasEitherOperand(IndirectMemberPointer)),
+                unless(hasEitherOperand(
+                    castExpr(hasCastKind(CK_NullToMemberPointer))))))
+          .bind("binary_operator"),
+      this);
+}
+
+void ComparePointerToMemberVirtualFunctionCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const BinaryOperator *BO =
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EugeneZelenko wrote:

`const auto *` could be used, because type is explicitly stated in same statement. Same below.

https://github.com/llvm/llvm-project/pull/66055