[PATCH] D142757: [clang][driver] Emit an error for `/clang:-x`

[Fangrui Song via Phabricator via cfe-commits]

MaskRay added inline comments.


================
Comment at: clang/lib/Driver/Driver.cpp:2571
     // No driver mode exposes -x and /TC or /TP; we don't support mixing them.
     assert(!Args.hasArg(options::OPT_x) && "-x and /TC or /TP is not allowed");
   }
----------------
Fznamznon wrote:
> MaskRay wrote:
> > ```
> > -    assert(!Args.hasArg(options::OPT_x) && "-x and /TC or /TP is not allowed");
> > +    if (auto *A = Args.getLastArg(options::OPT_x))
> > +      Diag(diag::err_drv_unsupported_opt_with_suggestion)
> > +          << A->getAsString(Args) << "/TC' or '/TP";
> > ```
> Thank you, the suggestion seems reasonable to me. Although, the concrete place doesn't.
> The suggested line to change is under if (we have /TC or /TP argument), so if I put error emission there it won't be emitted if no /TC or /TP was passed and the original problem reported in https://github.com/llvm/llvm-project/issues/59307 won't be resolved. People will still be confused by the warning saying `-x c` passed after last input when in fact they passed `/clang:-x` before the input.
> 
> Also, the whole function doesn't return even if diagnostic is emitted, so I put error emission in a way to not emit a warning saying that -x is passed after last input together with it, because both errors emitted like this:
> 
> error: '-x c' after last input file has no effect
> error: unsupported option '-x c'; did you mean '/TC' or '/TP'?
> 
> look confusing.
You need to remove `assert(!Args.hasArg(options::OPT_x) && "-x and /TC or /TP is not allowed");` as otherwise `/clang:-x /TC` leads to a crash in an assert build of clang (`LLVM_ENABLE_ASSERTIONS=on`).


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D142757/new/

https://reviews.llvm.org/D142757