Re: [google][4.8] Expose all target specific builtins unconditionally for LIPO builds

[Xinliang David Li <davidxl at google dot com>]

Can you collect some number on ggc_memory increase  with this change
in profile_gen build -- the value is recorded gcov_module_info object
in coverage.c.

thanks,

David

On Wed, Jul 24, 2013 at 3:14 PM, Sriraman Tallam <tmsriram@google.com> wrote:
> The following test-case fails in LIPO mode during profile-use build:
>
> main.cc
> ------------
> __attribute__((target("sse4.2")))
> unsigned int problem_aux (unsigned int A, unsigned int B);
>
>
> int main (int argc, char *argv[])
> {
>   return problem_aux (0, 0);
> }
>
> aux.cc
> ---------
> __attribute__((target("sse4.2")))
> unsigned int problem_aux (unsigned int A, unsigned int B)
> {
>   return __builtin_ia32_crc32qi (A, B);
> }
>
> $ g++ -O2 -fprofile-generate main.cc aux.cc
> $ ./a.out
> $ g++ -O2 -fprofile-use main.cc
> error: '__builtin_ia32_crc32qi' was not declared in this scope
>
> This happens when parsing the auxiliary module. __builtin_ia32_crc32qi
> is a target specific builtin that gets created after the target
> attribute is seen in the declaration of problem_aux in the primary
> module. This is too late for adding theisbuiltin to the list of
> knowns, the buitlins get saved when cp_save_built_in_decl_pre_parsing
> in cp/cp-objcp-common.c is called much earlier.  Hence, this builtin
> which is created during primary module parsing is not available when
> parsing the auxiliary module.
>
> A simple fix is to expose all target builtins unconditionally in LIPO
> mode. Patch:
>
>
> Index: config/i386/i386.c
> ===================================================================
> --- config/i386/i386.c  (revision 201046)
> +++ config/i386/i386.c  (working copy)
> @@ -26957,7 +26957,8 @@ def_builtin (HOST_WIDE_INT mask, const char *name,
>        ix86_builtins_isa[(int) code].isa = mask;
>
>        mask &= ~OPTION_MASK_ISA_64BIT;
> -      if (mask == 0
> +      if (flag_dyn_ipa
> +         || mask == 0
>           || (mask & ix86_isa_flags) != 0
>           || (lang_hooks.builtin_function
>               == lang_hooks.builtin_function_ext_scope))
>
>
> Is this ok?
>
> Thanks
> Sri