[Clang][AST] Temporarily undefine IBAction/IBOutlet ObjC macros in attribute headers

[gAlfonso-bit]

Summary

Taken from a downstream fork: https://github.com/apple/llvm-project/pull/3461/files.

IBAction and IBOutlet are defined when compiling with ObjC/ObjC++ enabled. This can cause issues due to macro expansion when we look through these header files while compiling in ObjC++ mode. This patch temporarily undefs these macros so that the compiler doesn't try to expand them when looking through these attribute headers.

[gAlfonso-bit]

This change is no longer necessary.

clang/include/clang/AST/Attr.h

 //===--- Attr.h - Classes for representing attributes ----------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
 //  This file defines the Attr interface and subclasses.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_AST_ATTR_H
 #define LLVM_CLANG_AST_ATTR_H
 
+#pragma push_macro("IBAction")
+#pragma push_macro("IBOutlet")
+#undef IBAction
+#undef IBOutlet
+
 #include "clang/AST/ASTFwd.h"
 #include "clang/AST/AttrIterator.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/AttrKinds.h"
 #include "clang/Basic/AttributeCommonInfo.h"
-#include "clang/Basic/LangOptions.h"
 #include "clang/Basic/LLVM.h"
+#include "clang/Basic/LangOptions.h"
 #include "clang/Basic/OpenMPKinds.h"
 #include "clang/Basic/Sanitizers.h"
 #include "clang/Basic/SourceLocation.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>

 
 inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
                                              const Attr *At) {
   DB.AddTaggedVal(reinterpret_cast<uint64_t>(At), DiagnosticsEngine::ak_attr);
   return DB;
 }
 }  // end namespace clang
 
+#pragma pop_macro("IBAction")
+#pragma pop_macro("IBOutlet")
+
 #endif

clang/include/clang/AST/RecursiveASTVisitor.h

 //===--- RecursiveASTVisitor.h - Recursive AST Visitor ----------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
 //  This file defines the RecursiveASTVisitor interface, which recursively
 //  traverses the entire AST.
 //
 //===----------------------------------------------------------------------===//
 #ifndef LLVM_CLANG_AST_RECURSIVEASTVISITOR_H
 #define LLVM_CLANG_AST_RECURSIVEASTVISITOR_H
 
+#pragma push_macro("IBAction")
+#pragma push_macro("IBOutlet")
+#undef IBAction
+#undef IBOutlet
+
 #include "clang/AST/Attr.h"
 #include "clang/AST/Decl.h"
-#include "clang/AST/DeclarationName.h"
 #include "clang/AST/DeclBase.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclFriend.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/DeclOpenMP.h"
 #include "clang/AST/DeclTemplate.h"
+#include "clang/AST/DeclarationName.h"
 #include "clang/AST/Expr.h"
-#include "clang/AST/ExprConcepts.h"
 #include "clang/AST/ExprCXX.h"
+#include "clang/AST/ExprConcepts.h"
 #include "clang/AST/ExprObjC.h"
 #include "clang/AST/ExprOpenMP.h"
 #include "clang/AST/LambdaCapture.h"
 #include "clang/AST/NestedNameSpecifier.h"
 #include "clang/AST/OpenMPClause.h"
 #include "clang/AST/Stmt.h"
 #include "clang/AST/StmtCXX.h"
 #include "clang/AST/StmtObjC.h"

 #undef DEF_TRAVERSE_STMT
 #undef TRAVERSE_STMT
 #undef TRAVERSE_STMT_BASE
 
 #undef TRY_TO
 
 } // end namespace clang
 
+#pragma pop_macro("IBAction")
+#pragma pop_macro("IBOutlet")
+
 #endif // LLVM_CLANG_AST_RECURSIVEASTVISITOR_H