Re: [PATCH] Do not prepend target triple to -fuse-ld=lld,mold.

[Richard Biener <rguenther@suse.de>]

On Mon, 16 Oct 2023, Tatsuyuki Ishi wrote:

> lld and mold are platform-agnostic and not prefixed with target triple.
> Prepending the target triple makes it less likely to find the intended
> linker executable.
> 
> A potential breaking change is that we no longer try to search for
> triple-prefixed lld/mold binaries anymore. However, since there doesn't
> seem to be support to build LLVM or mold with triple-prefixed executable
> names, it seems better to just not bother with that case.
> 
> 	PR driver/111605
> 
> gcc/Changelog:
> 
> 	* collect2.cc (main): Do not prepend target triple to
> 	-fuse-ld=lld,mold.
> ---
>  gcc/collect2.cc | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/gcc/collect2.cc b/gcc/collect2.cc
> index 63b9a0c233a..c943f9f577c 100644
> --- a/gcc/collect2.cc
> +++ b/gcc/collect2.cc
> @@ -865,12 +865,15 @@ main (int argc, char **argv)
>    int i;
>  
>    for (i = 0; i < USE_LD_MAX; i++)
> -    full_ld_suffixes[i]
>  #ifdef CROSS_DIRECTORY_STRUCTURE
> -      = concat (target_machine, "-", ld_suffixes[i], NULL);
> -#else
> -      = ld_suffixes[i];
> -#endif
> +    /* lld and mold are platform-agnostic and not prefixed with target
> +       triple.  */
> +    if (!(i == USE_LLD_LD || i == USE_MOLD_LD))
> +      full_ld_suffixes[i] = concat (target_machine, "-", ld_suffixes[i],
> +				    NULL);
> +    else
> +#endif
> +      full_ld_suffixes[i] = ld_suffixes[i];
>  
>    p = argv[0] + strlen (argv[0]);
>    while (p != argv[0] && !IS_DIR_SEPARATOR (p[-1]))

Since we later do

  /* Search the compiler directories for `ld'.  We have protection against
     recursive calls in find_a_file.  */
  if (ld_file_name == 0)
    ld_file_name = find_a_file (&cpath, ld_suffixes[selected_linker], 
X_OK);
  /* Search the ordinary system bin directories
     for `ld' (if native linking) or `TARGET-ld' (if cross).  */
  if (ld_file_name == 0)
    ld_file_name = find_a_file (&path, full_ld_suffixes[selected_linker], 
X_OK);

I wonder how having full_ld_suffixes[LLD|MOLD] == ld_suffixes[LLD|MOLD]
fixes anything?

Richard.