[clang] [webkit.RefCntblBaseVirtualDtor] Add support for NoVirtualDestructorBase. (PR #132497)

[Ryosuke Niwa via cfe-commits]

https://github.com/rniwa created https://github.com/llvm/llvm-project/pull/132497

This PR adds the support for WTF::NoVirtualDestructorBase, which signifies to the checker that the class is exempt from having a virtual destructor.

>From a49c213d2ccb82391eb6e550d440ef4e829ecfa8 Mon Sep 17 00:00:00 2001
From: Ryosuke Niwa <rniwa at webkit.org>
Date: Fri, 21 Mar 2025 18:13:35 -0700
Subject: [PATCH] [webkit.RefCntblBaseVirtualDtor] Add support for
 NoVirtualDestructorBase.

This PR adds the support for WTF::NoVirtualDestructorBase, which signifies to the checker that
the class is exempt from having a virtual destructor.
---
 .../WebKit/RefCntblBaseVirtualDtorChecker.cpp   | 10 +++++++++-
 .../WebKit/ref-cntbl-base-virtual-dtor.cpp      | 17 +++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/RefCntblBaseVirtualDtorChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/RefCntblBaseVirtualDtorChecker.cpp
index 77520f1f731c1..98c587d62978b 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/RefCntblBaseVirtualDtorChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/RefCntblBaseVirtualDtorChecker.cpp
@@ -202,6 +202,13 @@ class RefCntblBaseVirtualDtorChecker
           if (!C)
             continue;
 
+          bool isExempt = T.getAsString() == "NoVirtualDestructorBase" &&
+                          safeGetName(C->getParent()) == "WTF";
+          if (isExempt || ExemptDecls.contains(C)) {
+            ExemptDecls.insert(RD);
+            continue;
+          }
+
           if (auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(C)) {
             for (auto &Arg : CTSD->getTemplateArgs().asArray()) {
               if (Arg.getKind() != TemplateArgument::Type)
@@ -223,12 +230,13 @@ class RefCntblBaseVirtualDtorChecker
 
       llvm::SetVector<const CXXRecordDecl *> Decls;
       llvm::DenseSet<const CXXRecordDecl *> CRTPs;
+      llvm::DenseSet<const CXXRecordDecl *> ExemptDecls;
     };
 
     LocalVisitor visitor(this);
     visitor.TraverseDecl(const_cast<TranslationUnitDecl *>(TUD));
     for (auto *RD : visitor.Decls) {
-      if (visitor.CRTPs.contains(RD))
+      if (visitor.CRTPs.contains(RD) || visitor.ExemptDecls.contains(RD))
         continue;
       visitCXXRecordDecl(RD);
     }
diff --git a/clang/test/Analysis/Checkers/WebKit/ref-cntbl-base-virtual-dtor.cpp b/clang/test/Analysis/Checkers/WebKit/ref-cntbl-base-virtual-dtor.cpp
index 5cf7e7614d06e..fd4144d572e01 100644
--- a/clang/test/Analysis/Checkers/WebKit/ref-cntbl-base-virtual-dtor.cpp
+++ b/clang/test/Analysis/Checkers/WebKit/ref-cntbl-base-virtual-dtor.cpp
@@ -1,5 +1,13 @@
 // RUN: %clang_analyze_cc1 -analyzer-checker=webkit.RefCntblBaseVirtualDtor -verify %s
 
+namespace WTF {
+
+class NoVirtualDestructorBase { };
+
+};
+
+using WTF::NoVirtualDestructorBase;
+
 struct RefCntblBase {
   void ref() {}
   void deref() {}
@@ -19,6 +27,15 @@ struct [[clang::suppress]] SuppressedDerivedWithVirtualDtor : RefCntblBase {
   virtual ~SuppressedDerivedWithVirtualDtor() {}
 };
 
+class ClassWithoutVirtualDestructor : public NoVirtualDestructorBase {
+public:
+  void ref() const;
+  void deref() const;
+};
+
+class DerivedClassWithoutVirtualDestructor : public ClassWithoutVirtualDestructor {
+};
+
 // FIXME: Support attributes on base specifiers? Currently clang
 // doesn't support such attributes at all, even though it knows
 // how to parse them.