| Message ID | 20101216165611.GE26663@basil.fritz.box |
|---|---|
| State | New |
| Headers | show |
On Thu, Dec 16, 2010 at 5:56 PM, Andi Kleen <andi@firstfloor.org> wrote: > On Thu, Dec 16, 2010 at 03:39:33PM +0000, Joseph S. Myers wrote: >> On Thu, 16 Dec 2010, Richard Guenther wrote: >> >> > > I also tried to do it without opts.c, but setting an 0 initialization >> > > value for the -fno-lto entry, but that didn't work either. >> > >> > Huh, that's strange. Joseph, do you have any idea why? Is it because >> > of how flags get passed to collect2? >> >> Having both flto and fno-lto in common.opt seems dodgy. Try making the >> code in opts.c that handles OPT_flto check "value" (value == 0 meaning >> -fno-lto) instead. > > That worked. Here's an updated version. Ok now? Ok. Can you check if you also need to update the linker plugin to not claim object files if -fno-lto is in effect? Btw, what happens with -flto -fno-lto -flto? Thanks, Richard. > From: Andi Kleen <ak@linux.intel.com> > Date: Wed, 15 Dec 2010 20:10:22 +0100 > Subject: [PATCH] Fix -fno-lto (PR lto/46905) > > 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. > > 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. > > 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/opts.c b/gcc/opts.c > index 2c8e767..cc4181e 100644 > --- a/gcc/opts.c > +++ b/gcc/opts.c > @@ -1670,7 +1670,7 @@ common_handle_option (struct gcc_options *opts, > break; > > case OPT_flto: > - opts->x_flag_lto = ""; > + opts->x_flag_lto = value ? "" : NULL; > break; > > case OPT_w: >
On Sat, Dec 18, 2010 at 09:24:39PM +0100, Richard Guenther wrote: > On Thu, Dec 16, 2010 at 5:56 PM, Andi Kleen <andi@firstfloor.org> wrote: > > On Thu, Dec 16, 2010 at 03:39:33PM +0000, Joseph S. Myers wrote: > >> On Thu, 16 Dec 2010, Richard Guenther wrote: > >> > >> > > I also tried to do it without opts.c, but setting an 0 initialization > >> > > value for the -fno-lto entry, but that didn't work either. > >> > > >> > Huh, that's strange. Joseph, do you have any idea why? Is it because > >> > of how flags get passed to collect2? > >> > >> Having both flto and fno-lto in common.opt seems dodgy. Try making the > >> code in opts.c that handles OPT_flto check "value" (value == 0 meaning > >> -fno-lto) instead. > > > > That worked. Here's an updated version. Ok now? > > Ok. Committed. > > Can you check if you also need to update the linker plugin to not > claim object files if -fno-lto is in effect? When -fuse-linker-plugin is specified the plugin will be unconditionally called and always claim independent of any other options. > > Btw, what happens with -flto -fno-lto -flto? Does LTO on a simple test. -Andi
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/opts.c b/gcc/opts.c index 2c8e767..cc4181e 100644 --- a/gcc/opts.c +++ b/gcc/opts.c @@ -1670,7 +1670,7 @@ common_handle_option (struct gcc_options *opts, break; case OPT_flto: - opts->x_flag_lto = ""; + opts->x_flag_lto = value ? "" : NULL; break; case OPT_w: