On 16/06/2023 09:07, Jason Merrill wrote: > On 6/16/23 07:58, Alex Coplan wrote: > > Hi, > > > > This is a v3 patch addressing feedback for: > > https://gcc.gnu.org/pipermail/gcc-patches/2023-June/621714.html > > > > The only change since the previous version is that the new option is > > documented in invoke.texi (and the description in c.opt was shortened as > > requested). > > > > ------ > > > > macOS SDK headers using the CF_ENUM macro can expand to invalid C++ code > > of the form: > > > > typedef enum T : BaseType T; > > > > i.e. an elaborated-type-specifier with an additional enum-base. > > Upstream LLVM can be made to accept the above construct with > > -Wno-error=elaborated-enum-base. > > > > This patch adds the -Welaborated-enum-base warning to GCC and adjusts > > the C++ parser to emit this warning instead of rejecting this code > > outright. > > > > The macro expansion in the macOS headers occurs in the case that the > > compiler declares support for enums with underlying type using > > __has_feature, see > > https://gcc.gnu.org/pipermail/gcc-patches/2023-May/618450.html > > > > GCC rejecting this construct outright means that GCC fails to bootstrap > > on Darwin in the case that it (correctly) implements __has_feature and > > declares support for C++ enums with underlying type. > > > > With this patch, GCC can bootstrap on Darwin in combination with the > > (WIP) __has_feature patch posted at: > > https://gcc.gnu.org/pipermail/gcc-patches/2023-May/617878.html > > > > Bootstrapped/regtested on aarch64-linux-gnu and x86_64-apple-darwin. > > OK for trunk? > > OK, thanks.
Thanks for the reviews, pushed as g:b106f11dc6adb8df15cc5c268896d314c76ca35f. > > > Thanks, > > Alex > > > > gcc/c-family/ChangeLog: > > > > * c.opt (Welaborated-enum-base): New. > > > > gcc/ChangeLog: > > > > * doc/invoke.texi: Document -Welaborated-enum-base. > > > > gcc/cp/ChangeLog: > > > > * parser.cc (cp_parser_enum_specifier): Don't reject > > elaborated-type-specifier with enum-base, instead emit new > > Welaborated-enum-base warning. > > > > gcc/testsuite/ChangeLog: > > > > * g++.dg/cpp0x/enum40.C: Adjust expected diagnostics. > > * g++.dg/cpp0x/forw_enum6.C: Likewise. > > * g++.dg/cpp0x/elab-enum-base.C: New test. >
