[clang] [Clang] Fix: Handle member pointer in `EmitNullabilityChecks` (PR #227738)

[via cfe-commits]

https://github.com/def3r updated https://github.com/llvm/llvm-project/pull/227738

>From 3e85ab54be07e16a7929131a1c556d50c4c9aaf9 Mon Sep 17 00:00:00 2001
From: Ayaan Khan <ayaanandayaan2 at gmail.com>
Date: Wed, 30 Sep 2026 19:56:15 +0530
Subject: [PATCH 1/2] emit member ptr not null check

---
 clang/lib/CodeGen/CGDecl.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index e1ed66ae71243e..10ca7504262834 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -783,7 +783,14 @@ void CodeGenFunction::EmitNullabilityCheck(LValue LHS, llvm::Value *RHS,
   auto CheckOrdinal = SanitizerKind::SO_NullabilityAssign;
   auto CheckHandler = SanitizerHandler::TypeMismatch;
   SanitizerDebugLocation SanScope(this, {CheckOrdinal}, CheckHandler);
-  llvm::Value *IsNotNull = Builder.CreateIsNotNull(RHS);
+  llvm::Value *IsNotNull;
+  if (RHS->getType()->isAggregateType()) {
+    const MemberPointerType *MPT = LHS.getType()->getAs<MemberPointerType>();
+    assert(MPT && "Aggregate Type is not a Member Pointer Type");
+    IsNotNull = CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, RHS, MPT);
+  } else {
+    IsNotNull = Builder.CreateIsNotNull(RHS);
+  }
   llvm::Constant *StaticData[] = {
       EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(LHS.getType()),
       llvm::ConstantInt::get(Int8Ty, 0), // The LogAlignment info is unused.

>From 5a08ae381e989222e28ee29890c349e83c027bdf Mon Sep 17 00:00:00 2001
From: Ayaan Khan <ayaanandayaan2 at gmail.com>
Date: Thu, 1 Oct 2026 00:19:26 +0530
Subject: [PATCH 2/2] add test

---
 clang/test/CodeGenCXX/ubsan-nullability-assign.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/clang/test/CodeGenCXX/ubsan-nullability-assign.cpp b/clang/test/CodeGenCXX/ubsan-nullability-assign.cpp
index 08c7f0090220ee..0897424a75e643 100644
--- a/clang/test/CodeGenCXX/ubsan-nullability-assign.cpp
+++ b/clang/test/CodeGenCXX/ubsan-nullability-assign.cpp
@@ -2,6 +2,7 @@
 
 struct S1 {
   int *_Nonnull p;
+  void q() {}
 };
 
 struct S2 {
@@ -29,6 +30,18 @@ void f1(int *p) {
   // CHECK: store
   u.s2.s1.p = p;
 
+  using MemberPtr = void (S1::*)(void);
+
+  // CHECK: br i1 true, label %cont{{.*}}, !nosanitize
+  // CHECK: call void @__ubsan_handle_type_mismatch{{.*}} !nosanitize
+  // CHECK: store
+  MemberPtr _Nonnull qptr = &S1::q;
+
+  // CHECK: br i1 false, label %cont{{.*}}, !nosanitize
+  // CHECK: call void @__ubsan_handle_type_mismatch{{.*}} !nosanitize
+  // CHECK: store
+  MemberPtr _Nonnull nqptr = nullptr;
+
   // CHECK-NOT: __ubsan_handle_type_mismatch
   // CHECK-NOT: store
   // CHECK: ret void