From e7300e75b51a7e7d4e81975b4be7a6c65f9a8286 Mon Sep 17 00:00:00 2001 From: Aaron Ballman Date: Wed, 18 Jan 2023 08:49:45 -0500 Subject: Diagnose extensions in 'offsetof' https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2350.htm made very clear that it is an UB having type definitions with in offsetof. Clang supports defining a type as the first argument as a conforming extension due to how many projects use the construct in C99 and earlier to calculate the alignment of a type. GCC also supports defining a type as the first argument. This adds extension warnings and documentation for the functionality Clang explicitly supports. Fixes #57065 Reverts the revert of 39da55e8f548a11f7dadefa73ea73d809a5f1729 Co-authored-by: Yingchi Long Co-authored-by: Aaron Ballman Differential Revision: https://reviews.llvm.org/D133574 --- clang/lib/Parse/ParseDecl.cpp | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'clang/lib/Parse/ParseDecl.cpp') diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp index 56e8038..e6812ac 100644 --- a/clang/lib/Parse/ParseDecl.cpp +++ b/clang/lib/Parse/ParseDecl.cpp @@ -4965,14 +4965,15 @@ void Parser::ParseEnumSpecifier(SourceLocation StartLoc, DeclSpec &DS, bool IsDependent = false; const char *PrevSpec = nullptr; unsigned DiagID; - Decl *TagDecl = Actions.ActOnTag( - getCurScope(), DeclSpec::TST_enum, TUK, StartLoc, SS, Name, NameLoc, - attrs, AS, DS.getModulePrivateSpecLoc(), TParams, Owned, IsDependent, - ScopedEnumKWLoc, IsScopedUsingClassTag, BaseType, - DSC == DeclSpecContext::DSC_type_specifier, - DSC == DeclSpecContext::DSC_template_param || - DSC == DeclSpecContext::DSC_template_type_arg, - &SkipBody).get(); + Decl *TagDecl = + Actions.ActOnTag(getCurScope(), DeclSpec::TST_enum, TUK, StartLoc, SS, + Name, NameLoc, attrs, AS, DS.getModulePrivateSpecLoc(), + TParams, Owned, IsDependent, ScopedEnumKWLoc, + IsScopedUsingClassTag, + BaseType, DSC == DeclSpecContext::DSC_type_specifier, + DSC == DeclSpecContext::DSC_template_param || + DSC == DeclSpecContext::DSC_template_type_arg, + OffsetOfState, &SkipBody).get(); if (SkipBody.ShouldSkip) { assert(TUK == Sema::TUK_Definition && "can only skip a definition"); -- cgit v1.1