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

[Hans Wennborg via cfe-commits]

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"
>>
>>
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