[clang] 39da55e - Revert "Diagnose extensions in 'offsetof'"

Arthur Eubanks via cfe-commits cfe-commits at lists.llvm.org
Tue Jan 17 22:35:45 PST 2023


Author: Arthur Eubanks
Date: 2023-01-17T22:35:21-08:00
New Revision: 39da55e8f548a11f7dadefa73ea73d809a5f1729

URL: https://github.com/llvm/llvm-project/commit/39da55e8f548a11f7dadefa73ea73d809a5f1729
DIFF: https://github.com/llvm/llvm-project/commit/39da55e8f548a11f7dadefa73ea73d809a5f1729.diff

LOG: Revert "Diagnose extensions in 'offsetof'"

This reverts commit f1f0a0d8e8fdd2e534d9423b2e64c6b8aaa53aee.

Causes crashes on

$ echo 'typedef int a; void c() { __builtin_offsetof(struct {a b}, b); }' | bin/clang -cc1 -emit-llvm -o /dev/null - -x c

Added: 
    

Modified: 
    clang/docs/LanguageExtensions.rst
    clang/docs/ReleaseNotes.rst
    clang/include/clang/Basic/DiagnosticGroups.td
    clang/include/clang/Basic/DiagnosticParseKinds.td
    clang/include/clang/Basic/DiagnosticSemaKinds.td
    clang/include/clang/Parse/Parser.h
    clang/include/clang/Parse/RAIIObjectsForParser.h
    clang/include/clang/Sema/Sema.h
    clang/lib/Parse/ParseDecl.cpp
    clang/lib/Parse/ParseDeclCXX.cpp
    clang/lib/Parse/ParseExpr.cpp
    clang/lib/Sema/SemaDecl.cpp
    clang/lib/Sema/SemaDeclCXX.cpp
    clang/lib/Sema/SemaTemplate.cpp
    clang/test/C/drs/dr4xx.c
    clang/test/CXX/drs/dr4xx.cpp
    clang/test/Parser/declarators.c
    clang/test/SemaCXX/offsetof.cpp

Removed: 
    clang/test/C/C2x/n2350.c


################################################################################
diff  --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index dbec1cd7c1966..9b39dc23e0a5c 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -2360,50 +2360,6 @@ evaluated, so any side effects of the expression will be discarded.
 
 Query for this feature with ``__has_builtin(__builtin_assume)``.
 
-``__builtin_offsetof``
-----------------------
-
-``__builtin_offsetof`` is used to implement the ``offsetof`` macro, which
-calculates the offset (in bytes) to a given member of the given type.
-
-**Syntax**:
-
-.. code-block:: c++
-
-    __builtin_offsetof(type-name, member-designator)
-
-**Example of Use**:
-
-.. code-block:: c++
-
-  struct S {
-    char c;
-    int i;
-    struct T {
-      float f[2];
-    } t;
-  };
-
-  const int offset_to_i = __builtin_offsetof(struct S, i);
-  const int ext1 = __builtin_offsetof(struct U { int i; }, i); // C extension
-  const int ext2 = __builtin_offsetof(struct S, t.f[1]); // C & C++ extension
-
-**Description**:
-
-This builtin is usable in an integer constant expression which returns a value
-of type ``size_t``. The value returned is the offset in bytes to the subobject
-designated by the member-designator from the beginning of an object of type
-``type-name``. Clang extends the required standard functionality in a few ways:
-
-* In C language modes, the first argument may be the definition of a new type.
-  Any type declared this way is scoped to the nearest scope containing the call
-  to the builtin.
-* The second argument may be a member-designator designated by a series of
-  member access expressions using the dot (``.``) operator or array subscript
-  expressions.
-
-Query for this feature with ``__has_builtin(__builtin_offsetof)``.
-
 ``__builtin_call_with_static_chain``
 ------------------------------------
 

diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 288904b023863..b912f77887f9a 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -504,8 +504,7 @@ Non-comprehensive list of changes in this release
 - Clang can now generate a PCH when using ``-fdelayed-template-parsing`` for
   code with templates containing loop hint pragmas, OpenMP pragmas, and
   ``#pragma unused``.
-- Now diagnoses use of a member access expression or array subscript expression
-  within ``__builtin_offsetof`` and ``offsetof`` as being a Clang extension.
+
 
 New Compiler Flags
 ------------------
@@ -685,12 +684,6 @@ C2x Feature Support
       va_end(list);
     }
 
-- Diagnose type definitions in the ``type`` argument of ``__builtin_offsetof``
-  as a conforming C extension according to
-  `WG14 N2350 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm>`_.
-  Also documents the builtin appropriately. Note, a type definition in C++
-  continues to be rejected.
-
 C++ Language Changes in Clang
 -----------------------------
 - Implemented `DR692 <https://wg21.link/cwg692>`_, `DR1395 <https://wg21.link/cwg1395>`_,

diff  --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index d754fdb594c02..f71bb401e9a10 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -173,7 +173,6 @@ def DeleteNonVirtualDtor : DiagGroup<"delete-non-virtual-dtor",
                                       DeleteAbstractNonVirtualDtor]>;
 def AbstractFinalClass : DiagGroup<"abstract-final-class">;
 def FinalDtorNonFinalClass : DiagGroup<"final-dtor-non-final-class">;
-def GNUOffsetofExtensions : DiagGroup<"gnu-offsetof-extensions">;
 
 def CXX11CompatDeprecatedWritableStr :
   DiagGroup<"c++11-compat-deprecated-writable-strings">;
@@ -1140,9 +1139,9 @@ def GNU : DiagGroup<"gnu", [GNUAlignofExpression, GNUAnonymousStruct,
                             GNUFlexibleArrayUnionMember, GNUFoldingConstant,
                             GNUImaginaryConstant, GNUIncludeNext,
                             GNULabelsAsValue, GNULineMarker, GNUNullPointerArithmetic,
-                            GNUOffsetofExtensions, GNUPointerArith,
-                            RedeclaredClassMember, GNURedeclaredEnum,
-                            GNUStatementExpression, GNUStaticFloatInit,
+                            GNUPointerArith, RedeclaredClassMember,
+                            GNURedeclaredEnum, GNUStatementExpression,
+                            GNUStaticFloatInit,
                             GNUStringLiteralOperatorTemplate, GNUUnionCast,
                             GNUVariableSizedTypeNotAtEnd, ZeroLengthArray,
                             GNUZeroLineDirective,

diff  --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index 6bc35fadbf7e0..79035b4de163f 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -1607,11 +1607,6 @@ def err_import_in_wrong_fragment : Error<
 def err_export_empty : Error<"export declaration cannot be empty">;
 }
 
-def ext_offsetof_member_designator : Extension<
-  "using %select{a member access expression|an array subscript expression}0 "
-  "within '%select{__builtin_offsetof|offsetof}1' is a Clang extension">,
-  InGroup<GNUOffsetofExtensions>;
-
 let CategoryName = "Generics Issue" in {
 
 def err_objc_expected_type_parameter : Error<

diff  --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 02a6c2c4214e8..318bbd7e78d36 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1650,9 +1650,6 @@ def err_type_defined_in_condition : Error<
   "%0 cannot be defined in a condition">;
 def err_type_defined_in_enum : Error<
   "%0 cannot be defined in an enumeration">;
-def ext_type_defined_in_offsetof : Extension<
-  "defining a type within '%select{__builtin_offsetof|offsetof}0' is a Clang "
-  "extension">, InGroup<GNUOffsetofExtensions>;
 
 def note_pure_virtual_function : Note<
   "unimplemented pure virtual method %0 in %1">;

diff  --git a/clang/include/clang/Parse/Parser.h b/clang/include/clang/Parse/Parser.h
index 6f9581b9ea1fc..7a33532eec14e 100644
--- a/clang/include/clang/Parse/Parser.h
+++ b/clang/include/clang/Parse/Parser.h
@@ -62,7 +62,6 @@ class Parser : public CodeCompletionHandler {
   friend class ColonProtectionRAIIObject;
   friend class ParsingOpenMPDirectiveRAII;
   friend class InMessageExpressionRAIIObject;
-  friend class OffsetOfStateRAIIObject;
   friend class PoisonSEHIdentifiersRAIIObject;
   friend class ObjCDeclContextSwitch;
   friend class ParenBraceBracketBalancer;
@@ -249,8 +248,6 @@ class Parser : public CodeCompletionHandler {
   /// function call.
   bool CalledSignatureHelp = false;
 
-  Sema::OffsetOfKind OffsetOfState = Sema::OffsetOfKind::OOK_Outside;
-
   /// The "depth" of the template parameters currently being parsed.
   unsigned TemplateParameterDepth;
 

diff  --git a/clang/include/clang/Parse/RAIIObjectsForParser.h b/clang/include/clang/Parse/RAIIObjectsForParser.h
index cb525c9d0edd6..5ae609e600734 100644
--- a/clang/include/clang/Parse/RAIIObjectsForParser.h
+++ b/clang/include/clang/Parse/RAIIObjectsForParser.h
@@ -341,19 +341,6 @@ namespace clang {
     }
   };
 
-  class OffsetOfStateRAIIObject {
-    Sema::OffsetOfKind &OffsetOfState;
-    Sema::OffsetOfKind OldValue;
-
-  public:
-    OffsetOfStateRAIIObject(Parser &P, Sema::OffsetOfKind Value)
-        : OffsetOfState(P.OffsetOfState), OldValue(P.OffsetOfState) {
-      OffsetOfState = Value;
-    }
-
-    ~OffsetOfStateRAIIObject() { OffsetOfState = OldValue; }
-  };
-
   /// RAII object that makes sure paren/bracket/brace count is correct
   /// after declaration/statement parsing, even when there's a parsing error.
   class ParenBraceBracketBalancer {

diff  --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index 35e319879a98d..30c5ea608f7a0 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -3304,16 +3304,6 @@ class Sema final {
     TUK_Friend       // Friend declaration:  'friend struct foo;'
   };
 
-  enum OffsetOfKind {
-    // Not parsing a type within __builtin_offsetof.
-    OOK_Outside,
-    // Parsing a type within __builtin_offsetof.
-    OOK_Builtin,
-    // Parsing a type within macro "offsetof", defined in __buitin_offsetof
-    // To improve our diagnostic message.
-    OOK_Macro,
-  };
-
   Decl *ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
                  SourceLocation KWLoc, CXXScopeSpec &SS, IdentifierInfo *Name,
                  SourceLocation NameLoc, const ParsedAttributesView &Attr,
@@ -3322,7 +3312,7 @@ class Sema final {
                  bool &IsDependent, SourceLocation ScopedEnumKWLoc,
                  bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
                  bool IsTypeSpecifier, bool IsTemplateParamOrArg,
-                 OffsetOfKind OOK, SkipBodyInfo *SkipBody = nullptr);
+                 SkipBodyInfo *SkipBody = nullptr);
 
   Decl *ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
                                 unsigned TagSpec, SourceLocation TagLoc,

diff  --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 75937c0d6a952..56fe9c3ac7bac 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -4972,7 +4972,7 @@ void Parser::ParseEnumSpecifier(SourceLocation StartLoc, DeclSpec &DS,
       DSC == DeclSpecContext::DSC_type_specifier,
       DSC == DeclSpecContext::DSC_template_param ||
           DSC == DeclSpecContext::DSC_template_type_arg,
-      OffsetOfState, &SkipBody);
+      &SkipBody);
 
   if (SkipBody.ShouldSkip) {
     assert(TUK == Sema::TUK_Definition && "can only skip a definition");

diff  --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 227c1df2bdddd..5d721f48140f7 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -2074,7 +2074,7 @@ void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
         DSC == DeclSpecContext::DSC_type_specifier,
         DSC == DeclSpecContext::DSC_template_param ||
             DSC == DeclSpecContext::DSC_template_type_arg,
-        OffsetOfState, &SkipBody);
+        &SkipBody);
 
     // If ActOnTag said the type was dependent, try again with the
     // less common call.

diff  --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 392ed29467a97..b1bf988307b12 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -2592,21 +2592,10 @@ ExprResult Parser::ParseBuiltinPrimaryExpression() {
   }
   case tok::kw___builtin_offsetof: {
     SourceLocation TypeLoc = Tok.getLocation();
-    auto OOK = Sema::OffsetOfKind::OOK_Builtin;
-    if (Tok.getLocation().isMacroID()) {
-      StringRef MacroName = Lexer::getImmediateMacroNameForDiagnostics(
-          Tok.getLocation(), PP.getSourceManager(), getLangOpts());
-      if (MacroName == "offsetof")
-        OOK = Sema::OffsetOfKind::OOK_Macro;
-    }
-    TypeResult Ty;
-    {
-      OffsetOfStateRAIIObject InOffsetof(*this, OOK);
-      Ty = ParseTypeName();
-      if (Ty.isInvalid()) {
-        SkipUntil(tok::r_paren, StopAtSemi);
-        return ExprError();
-      }
+    TypeResult Ty = ParseTypeName();
+    if (Ty.isInvalid()) {
+      SkipUntil(tok::r_paren, StopAtSemi);
+      return ExprError();
     }
 
     if (ExpectAndConsume(tok::comma)) {
@@ -2629,12 +2618,6 @@ ExprResult Parser::ParseBuiltinPrimaryExpression() {
     Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
     Comps.back().LocStart = Comps.back().LocEnd = ConsumeToken();
 
-    enum class Kind { MemberAccess, ArraySubscript };
-    auto DiagExt = [&](SourceLocation Loc, Kind K) {
-      Diag(Loc, diag::ext_offsetof_member_designator)
-          << (K == Kind::ArraySubscript) << (OOK == Sema::OOK_Macro);
-    };
-
     // FIXME: This loop leaks the index expressions on error.
     while (true) {
       if (Tok.is(tok::period)) {
@@ -2648,9 +2631,9 @@ ExprResult Parser::ParseBuiltinPrimaryExpression() {
           SkipUntil(tok::r_paren, StopAtSemi);
           return ExprError();
         }
-        DiagExt(Comps.back().LocStart, Kind::MemberAccess);
         Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
         Comps.back().LocEnd = ConsumeToken();
+
       } else if (Tok.is(tok::l_square)) {
         if (CheckProhibitedCXX11Attribute())
           return ExprError();
@@ -2666,7 +2649,6 @@ ExprResult Parser::ParseBuiltinPrimaryExpression() {
           SkipUntil(tok::r_paren, StopAtSemi);
           return Res;
         }
-        DiagExt(Comps.back().LocStart, Kind::ArraySubscript);
         Comps.back().U.E = Res.get();
 
         ST.consumeClose();

diff  --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 0fd68c55cc172..baadaf3210ee4 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -16593,7 +16593,7 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
                      SourceLocation ScopedEnumKWLoc,
                      bool ScopedEnumUsesClassTag, TypeResult UnderlyingType,
                      bool IsTypeSpecifier, bool IsTemplateParamOrArg,
-                     OffsetOfKind OOK, SkipBodyInfo *SkipBody) {
+                     SkipBodyInfo *SkipBody) {
   // If this is not a definition, it must have a name.
   IdentifierInfo *OrigName = Name;
   assert((Name != nullptr || TUK == TUK_Definition) &&
@@ -17366,16 +17366,10 @@ Decl *Sema::ActOnTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
                                cast_or_null<RecordDecl>(PrevDecl));
   }
 
-  if (OOK != OOK_Outside && TUK == TUK_Definition && !getLangOpts().CPlusPlus) {
-    Diag(New->getLocation(), diag::ext_type_defined_in_offsetof)
-        << (OOK == OOK_Macro) << New->getSourceRange();
-    Invalid = true;
-  }
-
   // C++11 [dcl.type]p3:
   //   A type-specifier-seq shall not define a class or enumeration [...].
-  if (!Invalid && getLangOpts().CPlusPlus &&
-      (IsTypeSpecifier || IsTemplateParamOrArg) && TUK == TUK_Definition) {
+  if (getLangOpts().CPlusPlus && (IsTypeSpecifier || IsTemplateParamOrArg) &&
+      TUK == TUK_Definition) {
     Diag(New->getLocation(), diag::err_type_defined_in_type_specifier)
       << Context.getTagDeclType(New);
     Invalid = true;

diff  --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index cf1242beffe99..f66b8b722b9be 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -16974,15 +16974,15 @@ Decl *Sema::ActOnTemplatedFriendTag(Scope *S, SourceLocation FriendLoc,
     if (SS.isEmpty()) {
       bool Owned = false;
       bool IsDependent = false;
-      return ActOnTag(S, TagSpec, TUK_Friend, TagLoc, SS, Name, NameLoc, Attr,
-                      AS_public,
+      return ActOnTag(S, TagSpec, TUK_Friend, TagLoc, SS, Name, NameLoc,
+                      Attr, AS_public,
                       /*ModulePrivateLoc=*/SourceLocation(),
                       MultiTemplateParamsArg(), Owned, IsDependent,
                       /*ScopedEnumKWLoc=*/SourceLocation(),
                       /*ScopedEnumUsesClassTag=*/false,
                       /*UnderlyingType=*/TypeResult(),
                       /*IsTypeSpecifier=*/false,
-                      /*IsTemplateParamOrArg=*/false, /*OOK=*/OOK_Outside);
+                      /*IsTemplateParamOrArg=*/false);
     }
 
     NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);

diff  --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 1b30116192616..8466ed0da3901 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -10181,12 +10181,13 @@ Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
 
   bool Owned = false;
   bool IsDependent = false;
-  Decl *TagD = ActOnTag(
-      S, TagSpec, Sema::TUK_Reference, KWLoc, SS, Name, NameLoc, Attr, AS_none,
-      /*ModulePrivateLoc=*/SourceLocation(), MultiTemplateParamsArg(), Owned,
-      IsDependent, SourceLocation(), false, TypeResult(),
-      /*IsTypeSpecifier*/ false,
-      /*IsTemplateParamOrArg=*/false, /*OOK=*/OOK_Outside);
+  Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
+                        KWLoc, SS, Name, NameLoc, Attr, AS_none,
+                        /*ModulePrivateLoc=*/SourceLocation(),
+                        MultiTemplateParamsArg(), Owned, IsDependent,
+                        SourceLocation(), false, TypeResult(),
+                        /*IsTypeSpecifier*/false,
+                        /*IsTemplateParamOrArg*/false);
   assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
 
   if (!TagD)

diff  --git a/clang/test/C/C2x/n2350.c b/clang/test/C/C2x/n2350.c
deleted file mode 100644
index 93ab5070b6c63..0000000000000
--- a/clang/test/C/C2x/n2350.c
+++ /dev/null
@@ -1,74 +0,0 @@
-// RUN: %clang_cc1 -fsyntax-only -verify=silent %s
-// RUN: %clang_cc1 -fsyntax-only -verify=cpp -x c++ %s
-// RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -verify %s
-// RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c89 -verify %s
-// RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c99 -verify %s
-// RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c11 -verify %s
-// RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c17 -verify %s
-// RUN: %clang_cc1 -fsyntax-only -pedantic -Wno-comment -std=c2x -verify %s
-
-// silent-no-diagnostics
-
-// Reject definitions in __builtin_offsetof
-// https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm
-int simple(void) {
-  return __builtin_offsetof(struct A // cpp-error {{'A' cannot be defined in a type specifier}} \
-                                        expected-warning {{defining a type within '__builtin_offsetof' is a Clang extension}}
-  {
-    int a;
-    struct B // expected-warning {{defining a type within '__builtin_offsetof' is a Clang extension}}
-    {
-      int c;
-      int d;
-    } x;
-  }, a);
-}
-
-int anonymous_struct(void) {
-  return __builtin_offsetof(struct // cpp-error-re {{'(unnamed struct at {{.*}})' cannot be defined in a type specifier}} \
-                                      expected-warning {{defining a type within '__builtin_offsetof' is a Clang extension}}
-  {
-    int a;
-    int b;
-  }, a);
-}
-
-int struct_in_second_param(void) {
-  struct A {
-    int a, b;
-    int x[20];
-  };
-  return __builtin_offsetof(struct A, x[sizeof(struct B{int a;})]); // cpp-error {{'B' cannot be defined in a type specifier}} \
-                                                                       expected-warning {{using an array subscript expression within '__builtin_offsetof' is a Clang extension}}
-}
-
-
-#define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER)
-
-
-int macro(void) {
-  return offsetof(struct A // cpp-error {{'A' cannot be defined in a type specifier}} \
-                              expected-warning 2 {{defining a type within 'offsetof' is a Clang extension}}
-  {
-    int a;
-    struct B // verifier seems to think the error is emitted by the macro
-             // In fact the location of the error is "B" on the line above
-    {
-      int c;
-      int d;
-    } x;
-  }, a);
-}
-
-#undef offsetof
-
-#define offsetof(TYPE, MEMBER) (&((TYPE *)0)->MEMBER)
-
-// no warning for traditional offsetof as a function-like macro
-int * macro_func(void) {
-  return offsetof(struct A // cpp-error {{'A' cannot be defined in a type specifier}}
-  {
-    int a;
-    int b;
-  }, a);
-}

diff  --git a/clang/test/C/drs/dr4xx.c b/clang/test/C/drs/dr4xx.c
index 3ad9b17a83df1..768897cd4f2bb 100644
--- a/clang/test/C/drs/dr4xx.c
+++ b/clang/test/C/drs/dr4xx.c
@@ -337,13 +337,12 @@ void dr496(void) {
    * because it references an array of another struct. Clang calculates the
    * correct offset to each of those fields.
    */
-  _Static_assert(__builtin_offsetof(struct B, a.n) == 0, ""); /* expected-warning {{using a member access expression within '__builtin_offsetof' is a Clang extension}} */
+  _Static_assert(__builtin_offsetof(struct B, a.n) == 0, "");
   /* First int below is for 'n' and the second int is for 'a[0]'; this presumes
    * there is no padding involved.
    */
-  _Static_assert(__builtin_offsetof(struct B, a.a[1]) == sizeof(int) + sizeof(int), ""); /* expected-warning {{using a member access expression within '__builtin_offsetof' is a Clang extension}}
-                                                                                            expected-warning {{using an array subscript expression within '__builtin_offsetof' is a Clang extension}}
-                                                                                          */
+  _Static_assert(__builtin_offsetof(struct B, a.a[1]) == sizeof(int) + sizeof(int), "");
+
   /* However, we do not support using the -> operator to access a member, even
    * if that would be a valid expression. FIXME: GCC accepts this, perhaps we
    * should as well.
@@ -353,10 +352,11 @@ void dr496(void) {
                                              */
 
   /* The DR asked a question about whether defining a new type within offsetof
-   * is allowed. C2x N2350 made this explicitly undefined behavior, but GCC and
-   * Clang both support it as an extension.
+   * is allowed. C2x N2350 made this explicitly undefined behavior, but Clang
+   * has always supported defining a type in this location, and GCC also
+   * supports it.
    */
-   (void)__builtin_offsetof(struct S { int a; }, a); /* expected-warning{{defining a type within '__builtin_offsetof' is a Clang extension}} */
+   (void)__builtin_offsetof(struct S { int a; }, a);
 }
 
 /* WG14 DR499: yes

diff  --git a/clang/test/CXX/drs/dr4xx.cpp b/clang/test/CXX/drs/dr4xx.cpp
index 476d80ef0720d..3617af8b683c0 100644
--- a/clang/test/CXX/drs/dr4xx.cpp
+++ b/clang/test/CXX/drs/dr4xx.cpp
@@ -687,9 +687,9 @@ namespace dr447 { // dr447: yes
     U<__builtin_offsetof(A, n)>::type a;
     U<__builtin_offsetof(T, n)>::type b; // expected-error +{{}} expected-warning 0+{{}}
     // as an extension, we allow the member-designator to include array indices
-    g(__builtin_offsetof(A, a[0])).h<int>(); // expected-error {{using an array subscript expression within '__builtin_offsetof' is a Clang extension}}
-    g(__builtin_offsetof(A, a[N])).h<int>(); // expected-error {{using an array subscript expression within '__builtin_offsetof' is a Clang extension}}
-    U<__builtin_offsetof(A, a[0])>::type c; // expected-error {{using an array subscript expression within '__builtin_offsetof' is a Clang extension}}
+    g(__builtin_offsetof(A, a[0])).h<int>();
+    g(__builtin_offsetof(A, a[N])).h<int>();
+    U<__builtin_offsetof(A, a[0])>::type c;
     U<__builtin_offsetof(A, a[N])>::type d; // expected-error +{{}} expected-warning 0+{{}}
   }
 }

diff  --git a/clang/test/Parser/declarators.c b/clang/test/Parser/declarators.c
index 3af09817e6b63..464fafeaa0d27 100644
--- a/clang/test/Parser/declarators.c
+++ b/clang/test/Parser/declarators.c
@@ -80,6 +80,10 @@ struct test9 {
 struct test10 { int a; } static test10x;
 struct test11 { int a; } const test11x;
 
+// PR6216
+void test12(void) {
+  (void)__builtin_offsetof(struct { char c; int i; }, i);
+}
 
 // rdar://7608537
 struct test13 { int a; } (test13x);

diff  --git a/clang/test/SemaCXX/offsetof.cpp b/clang/test/SemaCXX/offsetof.cpp
index 39ea3804dce31..c4b288aa05d43 100644
--- a/clang/test/SemaCXX/offsetof.cpp
+++ b/clang/test/SemaCXX/offsetof.cpp
@@ -83,18 +83,3 @@ struct Derived : virtual Base {
                                                               expected-error {{invalid application of 'offsetof' to a field of a virtual base}}
 };
 }
-
-int test_definition(void) {
-  return __builtin_offsetof(struct A // expected-error {{'A' cannot be defined in a type specifier}}
-  {
-    int a;
-    struct B // FIXME: error diagnostic message for nested definitions
-             // https://reviews.llvm.org/D133574
-             // fixme-error{{'A' cannot be defined in '__builtin_offsetof'}}
-    {
-      int c;
-      int d;
-    };
-    B x;
-  }, a);
-}


        


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