[gomp4] acc routines bugfix

[Ilya Verbin]

On Fri, Jul 24, 2015 at 08:05:00 -0700, Cesar Philippidis wrote:
> The second point is interesting. Offloaded functions require the "omp
> target" attribute or that function won't reach the lto compiler. That's
> fine because not all targets can handle general code. The problem occurs
> when a user forgets to bless a function as offloaded, which OpenACC
> allows. This patch teaches the lto-wrapper to error on unrecognized
> functions with flag_openacc or hit gcc_unreachable otherwise. I couldn't
> think of a way to test the lto error message because that involves
> having two compilers present. I wonder if it's ok to have libgomp check
> for compiler expected compiler errors? However, that's more of a
> gcc/testsuite type of check.
> 
> I don't think trunk has much support for acc routines just yet, so I
> applied this patch to gomp-4_0-branch for now.

OpenMP has similar issue.

> diff --git a/gcc/lto-cgraph.c b/gcc/lto-cgraph.c
> index 97585c9..bc589bd 100644
> --- a/gcc/lto-cgraph.c
> +++ b/gcc/lto-cgraph.c
> @@ -1219,9 +1219,23 @@ input_overwrite_node (struct lto_file_decl_data *file_data,
>  				     LDPR_NUM_KNOWN);
>    node->instrumentation_clone = bp_unpack_value (bp, 1);
>    node->split_part = bp_unpack_value (bp, 1);
> -  gcc_assert (flag_ltrans
> -	      || (!node->in_other_partition
> -		  && !node->used_from_other_partition));
> +
> +  int success = flag_ltrans || (!node->in_other_partition
> +				&& !node->used_from_other_partition);
> +
> +  if (!success)
> +    {
> +      if (flag_openacc)
> +	{
> +	  if (TREE_CODE (node->decl) == FUNCTION_DECL)
> +	    error ("Missing routine function %<%s%>", node->name ());
> +	  else
> +	    error ("Missing declared variable %<%s%>", node->name ());
> +	}
> +
> +      else
> +	gcc_unreachable ();
> +    }
>  }

This will print an error not only when a fn/var, referenced from offload region,
missed its attribute, but also when something goes wrong in general LTO
partitioning (if flag_openacc is set).  So, maybe just replace gcc_assert ()
with error () without checking for flag_openacc?

And how about similar assert in input_varpool_node?

  -- Ilya