On Wed, Dec 14, 2022 at 1:56 AM chuanqi.xcq <yedeng...@linux.alibaba.com> wrote: > > Hi David, > > > I think Nathan might've been asking not only about what currently > happens, but what we think should happen? > > Yes. > > > Is that consistent with `-o`? (I assume so, but don't know - I guess > there aren't many cases where `-o` is unused (maybe `-fsyntax-only`), > so that behavior might be a bit less well specified) > > `-o` wouldn't emit a warning if it is not used. (with `-fsyntax-only` for > example). > Since we want to make the behavior of `-fmodule-output` to be consistent with > `-o`. > I've changed the behavior in https://reviews.llvm.org/D140001. > > > This seems surprising/possibly wrong to me - do we have precedent from > other flags to draw from? > > I feel it makes sense since `-fmodule-output=` will provide more information > than `-fmodule-output`. > So it is naturally to me that `-fmodule-output=` has higher priority. > > For examples, I don't enumerate all the flags but I find the following cases > in minutes: > - `-fpack-struct=` has higher priority than `-fpack-struct`. > - `-fsave-optimization-record=` has higher priority than > `-fsave-optimization-record=`. > - `-ftime-report=` has higher priority than `-ftime-report`. > - `-ftime-trace=` has higher priority than `-ftime-trace`. > > So I think the bahavior should be correct.
Fair enough - thanks for the references! Nathan - is that consistent with your preference/understanding/experience? > > Thanks, > Chuanqi > > > ------------------------------------------------------------------ > From:David Blaikie <dblai...@gmail.com> > Send Time:2022年12月13日(星期二) 23:56 > To:chuanqi.xcq <yedeng...@linux.alibaba.com> > Cc:Iain Sandoe <i...@sandoe.co.uk>; GCC Development <gcc@gcc.gnu.org>; Nathan > Sidwell <nathanmsidw...@gmail.com>; Jonathan Wakely <jwakely....@gmail.com>; > ben.boeckel <ben.boec...@kitware.com> > Subject:Re: Naming flag for specifying the output file name for Binary Module > Interface files > > I think Nathan might've been asking not only about what currently > happens, but what we think should happen? > > On Mon, Dec 12, 2022 at 7:11 PM chuanqi.xcq <yedeng...@linux.alibaba.com> > wrote: > > > > Hi Nathan, > > > > > 1) Are these flags silently ignored, if no module output is to be > > > generated? Or is some kind of diagnostic generated? > > > > Currently, clang will generate the unused-command-line-argument warning for > > this case: > > > > ``` > > argument unused during compilation: '-fmodule-output' > > [-Wunused-command-line-argument] > > ``` > > Is that consistent with `-o`? (I assume so, but don't know - I guess > there aren't many cases where `-o` is unused (maybe `-fsyntax-only`), > so that behavior might be a bit less well specified) > > > > 2) what happens if you specify both -- do you get two outputs, a > > > diagnostic, or > > is one silently selected? > > > > If someone specify both `-fmodule-output` and `-fmodule-output=/path`, > > the `-fmodule-output=/path` will be selected always no matter what the > > order is. > > This seems surprising/possibly wrong to me - do we have precedent from > other flags to draw from? > > > And if multiple `-fmodule-output=/path` are specified, the last one will be > > selected. > > > > > 3) What is the behaviour if compilation fails? Does nothing happen to > > > the file > > indicated (potentially leaving an older version there), or does the > > equivalent > > of 'rm -f $MODULE.pcm' happen? > > > > The module file will be deleted. The behavior is the same with `-o`. > > > > Thanks, > > Chuanqi > > > > > > ------------------------------------------------------------------ > > From:Nathan Sidwell <nat...@acm.org> > > Send Time:2022年12月12日(星期一) 22:30 > > To:Iain Sandoe <i...@sandoe.co.uk>; GCC Development <gcc@gcc.gnu.org> > > Cc:Nathan Sidwell <nathanmsidw...@gmail.com>; Jonathan Wakely > > <jwakely....@gmail.com>; David Blaikie <dblai...@gmail.com>; ben.boeckel > > <ben.boec...@kitware.com>; chuanqi.xcq <yedeng...@linux.alibaba.com> > > Subject:Re: Naming flag for specifying the output file name for Binary > > Module Interface files > > > > On 12/9/22 12:33, Iain Sandoe wrote: > > > Hello all. > > > > > >> On 9 Dec 2022, at 01:58, chuanqi.xcq <yedeng...@linux.alibaba.com> wrote: > > >> > > >> It looks like `-fmodule-file` is better from the discussion. So let's > > >> take it. Thanks for everyone here > > > > > > So FAOD (after this discussion) Chuanqi's current patchset implements the > > > following in clang: > > > > > > -fmodule-output > > > > > > - this causes the BMI to be saved in the CWG with the basename of the > > > source file and a suffix of .pcm. > > > > > > -fmodule-output=<path> > > > > > > - this causes the BMI to be saved at the path specified. > > > > > > > 1) Are these flags silently ignored, if no module output is to be > > generated? Or > > is some kind of diagnostic generated? > > > > 2) what happens if you specify both -- do you get two outputs, a > > diagnostic, or > > is one silently selected? > > > > 3) What is the behaviour if compilation fails? Does nothing happen to the > > file > > indicated (potentially leaving an older version there), or does the > > equivalent > > of 'rm -f $MODULE.pcm' happen? > > > > nathan > > > > -- > > Nathan Sidwell > > > > > >
