Ping: check initializer to be zero in .bss-like sections

["Jan Beulich" <JBeulich@suse.com>]

>>> On 10.12.15 at 08:21,  wrote:
> Just like gas, which has recently learned to reject such initializers,
> gcc shouldn't accept such either.
> ---
> The only question really is whether the new test case should be limited
> to certain targets - I haven't been able to figure out possible valid
> qualifiers to use here.
> 
> gcc/
> 2015-12-10  Jan Beulich  <jbeulich@suse.com>
> 
> 	* varasm.c (get_variable_section): Validate initializer in
> 	named .bss-like sections.
> 
> gcc/testsuite/
> 2015-12-10  Jan Beulich  <jbeulich@suse.com>
> 
> 	* gcc.dg/bss.c: New.
> 
> --- 2015-12-09/gcc/testsuite/gcc.dg/bss.c
> +++ 2015-12-09/gcc/testsuite/gcc.dg/bss.c
> @@ -0,0 +1,8 @@
> +/* Test non-zero initializers in .bss-like sections get properly refused.  
> */
> +/* { dg-do compile } */
> +/* { dg-options "" } */
> +
> +int __attribute__((section(".bss.local"))) x = 1; /* { dg-error "" "zero 
> init" } */
> +int *__attribute__((section(".bss.local"))) px = &x; /* { dg-error "" "zero 
> init" } */
> +int __attribute__((section(".bss.local"))) y = 0;
> +int *__attribute__((section(".bss.local"))) py = (void*)0;
> --- 2015-12-09/gcc/varasm.c
> +++ 2015-12-09/gcc/varasm.c
> @@ -1150,7 +1150,18 @@ get_variable_section (tree decl, bool pr
>  
>    resolve_unique_section (decl, reloc, flag_data_sections);
>    if (IN_NAMED_SECTION (decl))
> -    return get_named_section (decl, NULL, reloc);
> +    {
> +      section *sect = get_named_section (decl, NULL, reloc);
> +
> +      if ((sect->common.flags & SECTION_BSS) && !bss_initializer_p (decl))
> +	{
> +	  error_at (DECL_SOURCE_LOCATION (decl),
> +		    "only zero initializers are allowed in section %qs",
> +		    sect->named.name);
> +	  DECL_INITIAL (decl) = error_mark_node;
> +	}
> +      return sect;
> +    }
>  
>    if (ADDR_SPACE_GENERIC_P (as)
>        && !DECL_THREAD_LOCAL_P (decl)
> 
> 
>