[Clang] Add __builtin_common_reference

[philnik777]

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[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff f334db92be168876b618db72dc93078ce23ffa89 e0db7316b2705398a2ac7e69cd1e3e83ece52613 --extensions h,cpp -- clang/test/SemaCXX/type-trait-common-reference.cpp clang/include/clang/AST/ASTContext.h clang/include/clang/AST/ASTNodeTraverser.h clang/include/clang/AST/DeclID.h clang/include/clang/AST/DeclTemplate.h clang/include/clang/AST/RecursiveASTVisitor.h clang/include/clang/Basic/Builtins.h clang/include/clang/Sema/Sema.h clang/lib/AST/ASTContext.cpp clang/lib/AST/ASTImporter.cpp clang/lib/AST/DeclBase.cpp clang/lib/AST/DeclTemplate.cpp clang/lib/CodeGen/CGDecl.cpp clang/lib/Lex/PPMacroExpansion.cpp clang/lib/Sema/SemaExprCXX.cpp clang/lib/Sema/SemaLookup.cpp clang/lib/Sema/SemaTemplate.cpp clang/lib/Sema/SemaTemplateInstantiateDecl.cpp clang/lib/Sema/SemaType.cpp clang/lib/Serialization/ASTCommon.cpp clang/lib/Serialization/ASTReader.cpp clang/lib/Serialization/ASTWriter.cpp clang/tools/libclang/CIndex.cpp libcxx/include/__type_traits/common_reference.h

View the diff from clang-format here.

diff --git a/clang/include/clang/AST/DeclTemplate.h b/clang/include/clang/AST/DeclTemplate.h
index b765e0d17c..e94dcdb612 100644
--- a/clang/include/clang/AST/DeclTemplate.h
+++ b/clang/include/clang/AST/DeclTemplate.h
@@ -1807,9 +1807,7 @@ public:
     return new (C, DC) CVRefQualifyingTemplateDecl(C, DC, Ref);
   }
 
-  SourceRange getSourceRange() const override LLVM_READONLY {
-    return {};
-  }
+  SourceRange getSourceRange() const override LLVM_READONLY { return {}; }
 
   CVRefQuals getQuals() { return Quals; }
 };
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 635e2eb348..c43ebb2086 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -1697,11 +1697,9 @@ static TemplateParameterList *createBuiltinCommonTypeList(const ASTContext &C,
       nullptr);
 }
 
-static TemplateTypeParmDecl *BICreateTemplateParm(const ASTContext &C,
-                                                  DeclContext *DC,
-                                                  unsigned Depth,
-                                                  unsigned Position,
-                                                  bool ParameterPack = false) {
+static TemplateTypeParmDecl *
+BICreateTemplateParm(const ASTContext &C, DeclContext *DC, unsigned Depth,
+                     unsigned Position, bool ParameterPack = false) {
   return TemplateTypeParmDecl::Create(
       C, DC, SourceLocation(), SourceLocation(), Depth, Position,
       /*Id=*/nullptr, /*Typename=*/false, ParameterPack);
@@ -1733,8 +1731,8 @@ createBuiltinCommonReferenceBasicCommonReferenceT(const ASTContext &C,
                                       /*Position=*/0);
 }
 
-static TemplateParameterList *createBuiltinCommonReferenceList(const ASTContext &C,
-                                                          DeclContext *DC) {
+static TemplateParameterList *
+createBuiltinCommonReferenceList(const ASTContext &C, DeclContext *DC) {
   // template <class, class, template <class> class, template <class> class>
   // class
   auto *BasicCommonReference =
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 4706013ff7..6672fdedd0 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -3232,26 +3232,24 @@ static QualType CondRes(Sema &S, QualType X, QualType Y, SourceLocation Loc) {
   Sema::ContextRAII TUContext(S, S.Context.getTranslationUnitDecl());
 
   // false
-  OpaqueValueExpr CondExpr(SourceLocation(), S.Context.BoolTy,
-                            VK_PRValue);
+  OpaqueValueExpr CondExpr(SourceLocation(), S.Context.BoolTy, VK_PRValue);
   ExprResult Cond = &CondExpr;
 
   // declval<X(&)()>()()
   OpaqueValueExpr LHSExpr(Loc, X.getNonLValueExprType(S.Context),
-                              Expr::getValueKindForType(X));
+                          Expr::getValueKindForType(X));
   ExprResult LHS = &LHSExpr;
 
   // declval<Y(&)()>()()
   OpaqueValueExpr RHSExpr(Loc, Y.getNonLValueExprType(S.Context),
-                              Expr::getValueKindForType(Y));
+                          Expr::getValueKindForType(Y));
   ExprResult RHS = &RHSExpr;
 
   ExprValueKind VK = VK_PRValue;
   ExprObjectKind OK = OK_Ordinary;
 
   // decltype(false ? declval<X(&)()>()() : declval<Y(&)()>()())
-  QualType Result =
-      S.CheckConditionalOperands(Cond, LHS, RHS, VK, OK, Loc);
+  QualType Result = S.CheckConditionalOperands(Cond, LHS, RHS, VK, OK, Loc);
 
   if (SFINAE.hasErrorOccurred())
     return QualType();
@@ -3260,8 +3258,7 @@ static QualType CondRes(Sema &S, QualType X, QualType Y, SourceLocation Loc) {
   return Result;
 }
 
-static QualType CommonRef(Sema &S, QualType A, QualType B,
-                             SourceLocation Loc) {
+static QualType CommonRef(Sema &S, QualType A, QualType B, SourceLocation Loc) {
   // Given types A and B, let X be remove_reference_t<A>, let Y be
   // remove_reference_t<B>, and let COMMON-​REF(A, B) be:
   assert(A->isReferenceType() && B->isReferenceType() &&
@@ -3394,13 +3391,15 @@ static QualType builtinCommonReferenceImpl(Sema &S,
     auto T1 = Ts[0];
     auto T2 = Ts[1];
     auto Rest = Ts.drop_front(2);
-    auto C = builtinCommonReferenceImpl(S, CommonReference, CommonType, TemplateLoc, {T1, T2});
+    auto C = builtinCommonReferenceImpl(S, CommonReference, CommonType,
+                                        TemplateLoc, {T1, T2});
     if (C.isNull())
       return QualType();
     llvm::SmallVector<TemplateArgument, 4> Args;
     Args.emplace_back(C);
     Args.append(Rest.begin(), Rest.end());
-    return builtinCommonReferenceImpl(S, CommonReference, CommonType, TemplateLoc, Args);
+    return builtinCommonReferenceImpl(S, CommonReference, CommonType,
+                                      TemplateLoc, Args);
   }
   }
 }
diff --git a/libcxx/include/__type_traits/common_reference.h b/libcxx/include/__type_traits/common_reference.h
index a41143670b..31889b2c61 100644
--- a/libcxx/include/__type_traits/common_reference.h
+++ b/libcxx/include/__type_traits/common_reference.h
@@ -38,15 +38,16 @@ using common_reference_t = typename common_reference<_Types...>::type;
 template <class, class, template <class> class, template <class> class>
 struct basic_common_reference {};
 
-#if __has_builtin(__builtin_common_reference)
+#  if __has_builtin(__builtin_common_reference)
 
 template <class _Tp, class _Up, template <class> class _Tx, template <class> class _Ux>
 using __basic_common_reference_t = basic_common_reference<_Tp, _Up, _Tx, _Ux>::type;
 
 template <class... _Args>
-struct common_reference : __builtin_common_reference<__basic_common_reference_t, common_type_t, type_identity, __empty, _Args...> {};
+struct common_reference
+    : __builtin_common_reference<__basic_common_reference_t, common_type_t, type_identity, __empty, _Args...> {};
 
-#else
+#  else
 
 // Let COND_RES(X, Y) be:
 template <class _Xp, class _Yp>
@@ -198,7 +199,7 @@ struct common_reference<_Tp, _Up, _Vp, _Rest...> : common_reference<common_refer
 template <class...>
 struct common_reference {};
 
-#endif // __has_builtin(__builtin_common_reference)
+#  endif // __has_builtin(__builtin_common_reference)
 
 _LIBCPP_END_NAMESPACE_STD