r346491 - [clang-cl] Add warning for /Zc:dllexportInlines- when the flag is used with /fallback

Mon Nov 12 02:59:48 PST 2018

On Mon, Nov 12, 2018 at 4:58 AM Hans Wennborg <hans at chromium.org> wrote:

> Hmm, maybe I misunderstood your initial request for this.
>
> The current implementation does what the warnings says: If the
> compiler falls back to cl.exe, /Zc:dllexportInlines- will be ignored.
> This suggests to the user that it's a bad idea, but they can go ahead
> if they want to.
>
> It sounds like you're suggesting we should always ignore
> /Zc:dllexportInlines- when used together with the /fallback flag?

I thought we'd always emit an error if both flags are present, actually,
something like "/dllexportInlines- is ABI-changing and not compatible with
/fallback". If you still need /fallback, you can't really use
/dllexportInlines-.

> I'm
> not sure that's necessarily better.. it depends on why they're using
> /fallback I guess. If it's because the user has one file that clang-cl
> can't handle for some reason, but they still want
> /Zc:dllexportInlines- for the rest, then ignoring it would break that.
>
> In general, I'm not sure how widely used /fallback is anymore. I
> wonder if it would be possible to remove it...
>
> On Fri, Nov 9, 2018 at 9:52 PM, Nico Weber <thakis at chromium.org> wrote:
> > Ah cool. But the diagnostic is "option /dllexportInlines- is ignored when
> > /fallback happens" – shouldn't it be ignored regardless of if fallback
> > happens? Does that happen and the warning text is wrong?
> >
> > On Fri, Nov 9, 2018 at 11:20 AM Hans Wennborg <hans at chromium.org> wrote:
> >>
> >> On Fri, Nov 9, 2018 at 4:53 PM, Nico Weber <thakis at chromium.org> wrote:
> >> > This only prints the warning when /fallback actually happens, right?
> >>
> >> No, it prints it when the fallback job is created, not when (or if) it
> >> runs. I.e. it prints if the /fallback flag is used, regardless of
> >> whether it actually falls back or not. This is reflected by the test
> >> which uses -###, i.e. nothing is getting run.
> >>
> >> So I think we're good :-)
> >>
> >> > I don't
> >> > think that's good enough: If we build a few TUs with
> /dllexportInlines-
> >> > and
> >> > don't fall back, those .obj files are not abi compatible with the
> >> > cl-built
> >> > ones. (Consider all dllexport TUs of a header being built with
> clang-cl
> >> > but
> >> > all dllimport versions of the same header being built by cl – I think
> >> > this
> >> > will cause link errors). SO I think we should error out if
> >> > /dllexportIlnlines- /fallback is on the same line, even if the
> fallback
> >> > doesn't actually happen.
> >> >
> >> > On Fri, Nov 9, 2018 at 8:28 AM Takuto Ikuta via cfe-commits
> >> > <cfe-commits at lists.llvm.org> wrote:
> >> >>
> >> >> Author: tikuta
> >> >> Date: Fri Nov  9 05:25:45 2018
> >> >> New Revision: 346491
> >> >>
> >> >> URL: http://llvm.org/viewvc/llvm-project?rev=346491&view=rev
> >> >> Log:
> >> >> [clang-cl] Add warning for /Zc:dllexportInlines- when the flag is
> used
> >> >> with /fallback
> >> >>
> >> >> Summary:
> >> >> This is followup of
> >> >> https://reviews.llvm.org/D51340
> >> >>
> >> >> Reviewers: hans, thakis
> >> >>
> >> >> Reviewed By: hans
> >> >>
> >> >> Subscribers: cfe-commits, llvm-commits
> >> >>
> >> >> Differential Revision: https://reviews.llvm.org/D54298
> >> >>
> >> >> Modified:
> >> >>     cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td
> >> >>     cfe/trunk/lib/Driver/ToolChains/MSVC.cpp
> >> >>     cfe/trunk/test/Driver/cl-options.c
> >> >>
> >> >> Modified: cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td
> >> >> URL:
> >> >>
> >> >>
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td?rev=346491&r1=346490&r2=346491&view=diff
> >> >>
> >> >>
> >> >>
> ==============================================================================
> >> >> --- cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td (original)
> >> >> +++ cfe/trunk/include/clang/Basic/DiagnosticDriverKinds.td Fri Nov  9
> >> >> 05:25:45 2018
> >> >> @@ -161,6 +161,10 @@ def warn_drv_yc_multiple_inputs_clang_cl
> >> >>    "support for '/Yc' with more than one source file not implemented
> >> >> yet;
> >> >> flag ignored">,
> >> >>    InGroup<ClangClPch>;
> >> >>
> >> >> +def warn_drv_non_fallback_argument_clang_cl : Warning<
> >> >> +  "option '%0' is ignored when /fallback happens">,
> >> >> +  InGroup<OptionIgnored>;
> >> >> +
> >> >>  def err_drv_invalid_value : Error<"invalid value '%1' in '%0'">;
> >> >>  def err_drv_invalid_int_value : Error<"invalid integral value '%1'
> in
> >> >> '%0'">;
> >> >>  def err_drv_invalid_remap_file : Error<
> >> >>
> >> >> Modified: cfe/trunk/lib/Driver/ToolChains/MSVC.cpp
> >> >> URL:
> >> >>
> >> >>
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains/MSVC.cpp?rev=346491&r1=346490&r2=346491&view=diff
> >> >>
> >> >>
> >> >>
> ==============================================================================
> >> >> --- cfe/trunk/lib/Driver/ToolChains/MSVC.cpp (original)
> >> >> +++ cfe/trunk/lib/Driver/ToolChains/MSVC.cpp Fri Nov  9 05:25:45 2018
> >> >> @@ -669,6 +669,12 @@ std::unique_ptr<Command> visualstudio::C
> >> >>    // them too.
> >> >>    Args.AddAllArgs(CmdArgs, options::OPT_UNKNOWN);
> >> >>
> >> >> +  // Warning for ignored flag.
> >> >> +  if (const Arg *dllexportInlines =
> >> >> +      Args.getLastArg(options::OPT__SLASH_Zc_dllexportInlines_))
> >> >> +
> >> >>
> >> >>
> C.getDriver().Diag(clang::diag::warn_drv_non_fallback_argument_clang_cl)
> >> >> +      << dllexportInlines->getAsString(Args);
> >> >> +
> >> >>    // Input filename.
> >> >>    assert(Inputs.size() == 1);
> >> >>    const InputInfo &II = Inputs[0];
> >> >>
> >> >> Modified: cfe/trunk/test/Driver/cl-options.c
> >> >> URL:
> >> >>
> >> >>
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/cl-options.c?rev=346491&r1=346490&r2=346491&view=diff
> >> >>
> >> >>
> >> >>
> ==============================================================================
> >> >> --- cfe/trunk/test/Driver/cl-options.c (original)
> >> >> +++ cfe/trunk/test/Driver/cl-options.c Fri Nov  9 05:25:45 2018
> >> >> @@ -494,6 +494,8 @@
> >> >>  // NoDllExportInlines: "-fno-dllexport-inlines"
> >> >>  // RUN: %clang_cl /Zc:dllexportInlines /c -### -- %s 2>&1 |
> FileCheck
> >> >> -check-prefix=DllExportInlines %s
> >> >>  // DllExportInlines-NOT: "-fno-dllexport-inlines"
> >> >> +// RUN: %clang_cl /fallback /Zc:dllexportInlines- /c -### -- %s
> 2>&1 |
> >> >> FileCheck -check-prefix=DllExportInlinesFallback %s
> >> >> +// DllExportInlinesFallback: warning: option '/Zc:dllexportInlines-'
> >> >> is
> >> >> ignored when /fallback happens [-Woption-ignored]
> >> >>
> >> >>  // RUN: %clang_cl /Zi /c -### -- %s 2>&1 | FileCheck
> -check-prefix=Zi
> >> >> %s
> >> >>  // Zi: "-gcodeview"
> >> >>
> >> >>
> >> >> _______________________________________________
> >> >> cfe-commits mailing list
> >> >> cfe-commits at lists.llvm.org
> >> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20181112/365d9988/attachment.html>