[clang] [Clang] Fix __{add, remove}_pointer in Objective-C++ (PR #123678)

[Nikolas Klauser via cfe-commits]

https://github.com/philnik777 updated https://github.com/llvm/llvm-project/pull/123678

>From 2fe753b803a1067872a3d61ca04cdf49b7c023a6 Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Tue, 21 Jan 2025 02:16:02 +0100
Subject: [PATCH] [Clang] Fix __{add,remove}_pointer in Objective-C++

---
 clang/docs/ReleaseNotes.rst          |  2 ++
 clang/lib/Sema/SemaType.cpp          |  6 +++---
 clang/test/SemaObjCXX/type-traits.mm | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 3 deletions(-)
 create mode 100644 clang/test/SemaObjCXX/type-traits.mm

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8be1ea2fb01455..8c290437fe16fe 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -122,6 +122,8 @@ Bug Fixes in This Version
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+- The behvaiour of ``__add_pointer`` and ``__remove_pointer`` for Objective-C++'s ``id`` and interfaces has been fixed.
+
 Bug Fixes to Attribute Support
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 33d5378944ddbf..2781651b5d8f7d 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -1826,7 +1826,8 @@ QualType Sema::BuildPointerType(QualType T,
   if (checkQualifiedFunction(*this, T, Loc, QFK_Pointer))
     return QualType();
 
-  assert(!T->isObjCObjectType() && "Should build ObjCObjectPointerType");
+  if (T->isObjCObjectType())
+    return Context.getObjCObjectPointerType(T);
 
   // In ARC, it is forbidden to build pointers to unqualified pointers.
   if (getLangOpts().ObjCAutoRefCount)
@@ -9807,8 +9808,7 @@ QualType Sema::BuiltinAddPointer(QualType BaseType, SourceLocation Loc) {
 }
 
 QualType Sema::BuiltinRemovePointer(QualType BaseType, SourceLocation Loc) {
-  // We don't want block pointers or ObjectiveC's id type.
-  if (!BaseType->isAnyPointerType() || BaseType->isObjCIdType())
+  if (!BaseType->isAnyPointerType())
     return BaseType;
 
   return BaseType->getPointeeType();
diff --git a/clang/test/SemaObjCXX/type-traits.mm b/clang/test/SemaObjCXX/type-traits.mm
new file mode 100644
index 00000000000000..20cb980e8880bf
--- /dev/null
+++ b/clang/test/SemaObjCXX/type-traits.mm
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -fsyntax-only -verify -std=c++17  %s
+
+// expected-no-diagnostics
+
+ at interface I;
+ at end
+
+static_assert(__is_same(__add_pointer(id), id*));
+static_assert(__is_same(__add_pointer(I), I*));
+
+static_assert(!__is_same(__remove_pointer(id), id));
+static_assert(__is_same(__remove_pointer(id*), id));
+static_assert(__is_same(__remove_pointer(__add_pointer(id)), id));
+static_assert(__is_same(__add_pointer(__remove_pointer(id)), id));