Hi!

On 2023-01-11T13:31:56+0100, Jakub Jelinek via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> On Wed, Jan 11, 2023 at 12:41:06PM +0100, Thomas Schwinge wrote:
>
> I think this should be reviewed by Joseph as option handling maintainer.

Joseph, please?

>> +@item -Wno-complain-wrong-lang
>> +@opindex Wcomplain-wrong-lang
>> +@opindex Wno-complain-wrong-lang
>> +By default, we complain about command-line options that are not valid
>> +for this front end.
>> +This may be disabled with @code{-Wno-complain-wrong-lang}.
>
> I think this description is too short and confusing, it isn't clear what
> "this" front end is, perhaps say "that are not valid for a front end
> which compiles a particular source file"?
> And certainly give an example and more explanation that the option is
> mostly useful when a single compiler driver invocation is compiling
> multiple sources written in different languages.

Good suggestion, thanks.  I've changed the documentation as follows:

    --- gcc/common.opt
    +++ gcc/common.opt
     Wcomplain-wrong-lang
     Common Var(warn_complain_wrong_lang) Init(1) Warning
    -Complain when a command-line option is not valid for this front end.
    +Complain when a command-line option is valid, but not applicable to the current front end.

    --- gcc/doc/invoke.texi
    +++ gcc/doc/invoke.texi
    @@ -8943,9 +8943,21 @@ Warn for variables that might be changed by @code{longjmp} or
     @item -Wno-complain-wrong-lang
     @opindex Wcomplain-wrong-lang
     @opindex Wno-complain-wrong-lang
    -By default, we complain about command-line options that are not valid
    -for this front end.
    -This may be disabled with @code{-Wno-complain-wrong-lang}.
    +By default, language front ends complain when a command-line option is
    +valid, but not applicable to that front end.
    +This may be disabled with @option{-Wno-complain-wrong-lang},
    +which is mostly useful when invoking a single compiler driver for
    +multiple source files written in different languages, for example:
    +
    +@smallexample
    +$ g++ -fno-rtti a.cc b.f90
    +@end smallexample
    +
    +The driver @file{g++} invokes the C++ front end to compile @file{a.cc}
    +and the Fortran front end to compile @file{b.f90}.
    +The latter front end diagnoses
    +@samp{f951: Warning: command-line option '-fno-rtti' is valid for C++/D/ObjC++ but not for Fortran},
    +which may be disabled with @option{-Wno-complain-wrong-lang}.

Is the attached v2
"Add '-Wno-complain-wrong-lang', and use it in 'gcc/testsuite/lib/target-supports.exp:check_compile' and elsewhere"
OK?


Grüße
 Thomas


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