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/Sema/SemaTemplate.cpp | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'clang/lib/Sema/SemaTemplate.cpp') diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp index 6b49c3f..b40bd09 100644 --- a/clang/lib/Sema/SemaTemplate.cpp +++ b/clang/lib/Sema/SemaTemplate.cpp @@ -10181,13 +10181,11 @@ 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).get(); + 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).get(); assert(!IsDependent && "explicit instantiation of dependent name not yet handled"); if (!TagD) -- cgit v1.1