On Tue, Jun 4, 2024 at 7:54 AM Jason Merrill <ja...@redhat.com> wrote:
>
> On 3/14/24 04:01, Ken Matsui wrote:
> > On Sat, Mar 2, 2024 at 5:04 AM Ken Matsui <kmat...@gcc.gnu.org> wrote:
> >>
> >> This patch adds a warning switch for "#pragma once in main file". The
> >> warning option name is Wpragma-once-outside-header, which is the same
> >> as Clang.
> >
> > Ping.
> >
> >>
> >> PR preprocessor/89808
> >>
> >> gcc/c-family/ChangeLog:
> >>
> >> * c-opts.cc (c_common_handle_option): Handle
> >> OPT_Wpragma_once_outside_header.
> >> * c.opt (Wpragma_once_outside_header): Define new option.
> >>
> >> gcc/ChangeLog:
> >>
> >> * doc/invoke.texi (Warning Options): Document
> >> -Wno-pragma-once-outside-header.
> >>
> >> libcpp/ChangeLog:
> >>
> >> * include/cpplib.h (struct cpp_options): Define
> >> cpp_warn_pragma_once_outside_header.
> >> * directives.cc (do_pragma_once): Use
> >> cpp_warn_pragma_once_outside_header.
> >> * init.cc (cpp_create_reader): Handle
> >> cpp_warn_pragma_once_outside_header.
> >>
> >> gcc/testsuite/ChangeLog:
> >>
> >> * g++.dg/Wpragma-once-outside-header.C: New test.
>
> Please drop this file, keeping the duplicate in the warn subdirectory.
>
> >> * g++.dg/warn/Wno-pragma-once-outside-header.C: New test.
> >> * g++.dg/warn/Wpragma-once-outside-header.C: New test.
> >>
> >> Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
> >> ---
> >> gcc/c-family/c-opts.cc | 9 +++++++++
> >> gcc/c-family/c.opt | 4 ++++
> >> gcc/doc/invoke.texi | 10 ++++++++--
> >> gcc/testsuite/g++.dg/Wpragma-once-outside-header.C | 5 +++++
> >> .../g++.dg/warn/Wno-pragma-once-outside-header.C | 5 +++++
> >> .../g++.dg/warn/Wpragma-once-outside-header.C | 5 +++++
> >> libcpp/directives.cc | 8 ++++++--
> >> libcpp/include/cpplib.h | 4 ++++
> >> libcpp/init.cc | 1 +
> >> 9 files changed, 47 insertions(+), 4 deletions(-)
> >> create mode 100644 gcc/testsuite/g++.dg/Wpragma-once-outside-header.C
> >> create mode 100644
> >> gcc/testsuite/g++.dg/warn/Wno-pragma-once-outside-header.C
> >> create mode 100644
> >> gcc/testsuite/g++.dg/warn/Wpragma-once-outside-header.C
> >>
> >> diff --git a/gcc/c-family/c-opts.cc b/gcc/c-family/c-opts.cc
> >> index be3058dca63..4edd8c6c515 100644
> >> --- a/gcc/c-family/c-opts.cc
> >> +++ b/gcc/c-family/c-opts.cc
> >> @@ -430,6 +430,15 @@ c_common_handle_option (size_t scode, const char
> >> *arg, HOST_WIDE_INT value,
> >> cpp_opts->warn_num_sign_change = value;
> >> break;
> >>
> >> + case OPT_Wpragma_once_outside_header:
> >> + if (value == 0)
> >> + cpp_opts->cpp_warn_pragma_once_outside_header = 0;
> >> + else if (kind == DK_ERROR)
> >> + cpp_opts->cpp_warn_pragma_once_outside_header = 2;
> >> + else
> >> + cpp_opts->cpp_warn_pragma_once_outside_header = 1;
> >> + break;
>
> Rather than encode the -Werror this way...
>
> >> case OPT_Wunknown_pragmas:
> >> /* Set to greater than 1, so that even unknown pragmas in
> >> system headers will be warned about. */
> >> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
> >> index b7a4a1a68e3..6841a5a5e81 100644
> >> --- a/gcc/c-family/c.opt
> >> +++ b/gcc/c-family/c.opt
> >> @@ -1180,6 +1180,10 @@ Wpragmas
> >> C ObjC C++ ObjC++ Var(warn_pragmas) Init(1) Warning
> >> Warn about misuses of pragmas.
> >>
> >> +Wpragma-once-outside-header
> >> +C ObjC C++ ObjC++ Var(warn_pragma_once_outside_header) Init(1) Warning
> >> +Warn about #pragma once outside of a header.
> >> +
> >> Wprio-ctor-dtor
> >> C ObjC C++ ObjC++ Var(warn_prio_ctor_dtor) Init(1) Warning
> >> Warn if constructor or destructors with priorities from 0 to 100 are
> >> used.
> >> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> >> index bdf05be387d..eeb8954bcdf 100644
> >> --- a/gcc/doc/invoke.texi
> >> +++ b/gcc/doc/invoke.texi
> >> @@ -391,8 +391,8 @@ Objective-C and Objective-C++ Dialects}.
> >> -Wpacked -Wno-packed-bitfield-compat -Wpacked-not-aligned -Wpadded
> >> -Wparentheses -Wno-pedantic-ms-format
> >> -Wpointer-arith -Wno-pointer-compare -Wno-pointer-to-int-cast
> >> --Wno-pragmas -Wno-prio-ctor-dtor -Wredundant-decls
> >> --Wrestrict -Wno-return-local-addr -Wreturn-type
> >> +-Wno-pragmas -Wno-pragma-once-outside-header -Wno-prio-ctor-dtor
> >> +-Wredundant-decls -Wrestrict -Wno-return-local-addr -Wreturn-type
> >> -Wno-scalar-storage-order -Wsequence-point
> >> -Wshadow -Wshadow=global -Wshadow=local -Wshadow=compatible-local
> >> -Wno-shadow-ivar
> >> @@ -7955,6 +7955,12 @@ Do not warn about misuses of pragmas, such as
> >> incorrect parameters,
> >> invalid syntax, or conflicts between pragmas. See also
> >> @option{-Wunknown-pragmas}.
> >>
> >> +@opindex Wno-pragma-once-outside-header
> >> +@opindex Wpragma-once-outside-header
> >> +@item -Wno-pragma-once-outside-header
> >> +Do not warn when @code{#pragma once} is used in a file that is not a
> >> header
> >> +file, such as a main file.
> >> +
> >> @opindex Wno-prio-ctor-dtor
> >> @opindex Wprio-ctor-dtor
> >> @item -Wno-prio-ctor-dtor
> >> diff --git a/gcc/testsuite/g++.dg/Wpragma-once-outside-header.C
> >> b/gcc/testsuite/g++.dg/Wpragma-once-outside-header.C
> >> new file mode 100644
> >> index 00000000000..678bd4e7626
> >> --- /dev/null
> >> +++ b/gcc/testsuite/g++.dg/Wpragma-once-outside-header.C
> >> @@ -0,0 +1,5 @@
> >> +/* { dg-do assemble } */
> >> +/* { dg-options "-Werror=pragma-once-outside-header" } */
> >> +
> >> +#pragma once // { dg-error "#pragma once in main file" }
> >> +int main() {}
> >> diff --git a/gcc/testsuite/g++.dg/warn/Wno-pragma-once-outside-header.C
> >> b/gcc/testsuite/g++.dg/warn/Wno-pragma-once-outside-header.C
> >> new file mode 100644
> >> index 00000000000..b5be4d25a9d
> >> --- /dev/null
> >> +++ b/gcc/testsuite/g++.dg/warn/Wno-pragma-once-outside-header.C
> >> @@ -0,0 +1,5 @@
> >> +// { dg-do assemble }
> >> +// { dg-options "-Wno-pragma-once-outside-header" }
> >> +
> >> +#pragma once
> >> +int main() {}
> >> diff --git a/gcc/testsuite/g++.dg/warn/Wpragma-once-outside-header.C
> >> b/gcc/testsuite/g++.dg/warn/Wpragma-once-outside-header.C
> >> new file mode 100644
> >> index 00000000000..ae958d3beb8
> >> --- /dev/null
> >> +++ b/gcc/testsuite/g++.dg/warn/Wpragma-once-outside-header.C
> >> @@ -0,0 +1,5 @@
> >> +// { dg-do assemble }
> >> +// { dg-options "-Werror=pragma-once-outside-header" }
> >> +
> >> +#pragma once // { dg-error "#pragma once in main file" }
> >> +int main() {}
> >> diff --git a/libcpp/directives.cc b/libcpp/directives.cc
> >> index 479f8c716e8..b6121a459f8 100644
> >> --- a/libcpp/directives.cc
> >> +++ b/libcpp/directives.cc
> >> @@ -1588,8 +1588,12 @@ do_pragma (cpp_reader *pfile)
> >> static void
> >> do_pragma_once (cpp_reader *pfile)
> >> {
> >> - if (_cpp_in_main_source_file (pfile))
> >> - cpp_error (pfile, CPP_DL_WARNING, "#pragma once in main file");
> >> + const unsigned char warn_level =
> >> + CPP_OPTION (pfile, cpp_warn_pragma_once_outside_header);
> >> +
> >> + if (warn_level && _cpp_in_main_source_file (pfile))
> >> + cpp_error (pfile, (warn_level == 1 ? CPP_DL_WARNING : CPP_DL_ERROR),
> >> + "#pragma once in main file");
>
> ...it would seem better to use cpp_warning and add a cpp_warning_reason
> for this diagnostic, so the normal -Werror handling (including #pragma
> GCC diagnostic) takes care of it?
Thank you for your review! I'll soon update this patch.
>
> Jason
>
