On Fri, 2020-11-13 at 09:57 -0500, Austin Morton via Gcc-patches wrote: > On the contrary, as a user of GCC I would much prefer a consistent > behavior for #pragma region based purely on GCC version. > > IE, so you can tell people: > "just update to GCC X.Y and those warnings will go away" > rather than: > "update to GCC X.Y and pass some new flags - but make sure > not to pass them to old GCC versions, since that will generate > a new warning" > > I do agree it may be generally useful to have a configurable way to > specify pragmas to ignore at runtime, but that is not what I was > trying > to accomplish here. > > Both clang and MSVC handle this pragma without any runtime > configuration, and I think GCC should as well.
FWIW I like the patch (but I don't think I can approve it). How much does this pragma get used "in the wild"? Thinking aloud, I wonder if it would be useful to capture regions in the diagnostic subsystem, and emit "In region <FOO>..." messages, rather like we emit "In function <FOO>..." when first emitting a diagnostic within a region? (not sure if good idea, just brainstorming) Dave > Austin > > On Thu, Nov 12, 2020 at 11:25 PM Jeff Law <l...@redhat.com> wrote: > > > > On 9/2/20 6:59 PM, Austin Morton via Gcc-patches wrote: > > > #pragma region is a feature introduced by Microsoft in order to > > > allow > > > manual grouping and folding of code within Visual Studio. It is > > > entirely ignored by the compiler. Clang has supported this > > > feature > > > since 2012 when in MSVC compatibility mode, and enabled it across > > > the > > > board in 2018. > > > > > > As it stands, you cannot use #pragma region within GCC without > > > disabling unknown pragma warnings, which is not advisable. > > > > > > I propose GCC adopt "#pragma region" and "#pragma endregion" in > > > order > > > to alleviate these issues. Because the pragma has no purpose at > > > compile time, the implementation is trivial. > > > > > > > > > Microsoft Documentation on the feature: > > > https://docs.microsoft.com/en-us/cpp/preprocessor/region-endregion > > > > > > LLVM change which enabled pragma region across the board: > > > https://reviews.llvm.org/D42248 > > > --- > > > gcc/ChangeLog | 5 +++++ > > > gcc/c-family/ChangeLog | 5 +++++ > > > gcc/c-family/c-pragma.c | 10 ++++++++++ > > > gcc/doc/cpp.texi | 6 ++++++ > > > gcc/testsuite/ChangeLog | 5 +++++ > > > gcc/testsuite/gcc.dg/pragma-region.c | 21 +++++++++++++++++++++ > > > 6 files changed, 52 insertions(+) > > > create mode 100644 gcc/testsuite/gcc.dg/pragma-region.c > > > > I'm not sure that this is really the way we want to handle this > > stuff. > > I understand the problem you're trying to solve, but embedding a > > list of > > pragmas to ignore into the compiler itself just seems like the > > wrong > > approach -- it bakes that set of pragmas to ignore into the > > compiler. > > > > > > ISTM that we'd be better off either having a command line option to > > list > > the set of pragmas to ignore, or they should be pulled from a file > > specified on the command line. That would seem to be a lot more > > friendly to downstream users since each project could set the list > > of > > pragmas to ignore on their own and have that set updated > > dynamically > > over time without having to patch and update GCC. > > > > > > Any chance you would be willing to work on that? > > > > Jeff > >