[PATCH 1/2] Fix -fno-lto (PR lto/46905)

[Richard Guenther]

On Thu, Dec 16, 2010 at 1:41 PM, Andi Kleen <andi@firstfloor.org> wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
> This fixes PR lto/46905.
>
> It's sometimes convenient in large Makefiles to globally enable LTO
> in CFLAGS, but disable it again for specific files. The simplest
> way to do that is appending -fno-lto, but that didn't work.
> Add explicit code to handle this case.
>
> Passes bootstrap and full test on x86_64-linux. Ok?

Do you really need the common.opt and opts.c hunks?

> gcc/
>
> 2010-12-15  Andi Kleen  <ak@linux.intel.com>
>
>        PR lto/46905
>        * collect2.c (main): Handle -fno-lto.
>        * common.opt (fno-lto): Add.
>        * opts.c (common_handle_option): Handle OPT_fno_lto.
> ---
>  gcc/collect2.c |    2 ++
>  gcc/common.opt |    4 ++++
>  gcc/opts.c     |    4 ++++
>  3 files changed, 10 insertions(+), 0 deletions(-)
>
> diff --git a/gcc/collect2.c b/gcc/collect2.c
> index 89b21d5..77f794f 100644
> --- a/gcc/collect2.c
> +++ b/gcc/collect2.c
> @@ -1211,6 +1211,8 @@ main (int argc, char **argv)
>         else if ((! strncmp (argv[i], "-flto=", 6)
>                  || ! strcmp (argv[i], "-flto")) && ! use_plugin)
>          lto_mode = LTO_MODE_WHOPR;
> +       else if (!strncmp (argv[i], "-fno-lto", 8))
> +         lto_mode = LTO_MODE_NONE;
>         else if (! strcmp (argv[i], "-plugin"))
>          {
>            use_plugin = true;
> diff --git a/gcc/common.opt b/gcc/common.opt
> index 32df6fc..e6cb5e4 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -1302,6 +1302,10 @@ floop-optimize
>  Common Ignore
>  Does nothing.  Preserved for backward compatibility.
>
> +fno-lto
> +Common RejectNegative
> +Disable link-time optimization
> +
>  flto
>  Common
>  Enable link-time optimization.
> diff --git a/gcc/opts.c b/gcc/opts.c
> index 2c8e767..fc6f272 100644
> --- a/gcc/opts.c
> +++ b/gcc/opts.c
> @@ -1673,6 +1673,10 @@ common_handle_option (struct gcc_options *opts,
>       opts->x_flag_lto = "";
>       break;
>
> +    case OPT_fno_lto:
> +      opts->x_flag_lto = NULL;
> +      break;
> +
>     case OPT_w:
>       dc->dc_inhibit_warnings = true;
>       break;
> --
> 1.7.1
>
>