[PATCH] Fix ICE in categorize_decl_for_section with TLS decl (PR middle-end/82095)

[Jeff Law]

On 09/05/2017 03:16 PM, Jakub Jelinek wrote:
> Hi!
> 
> If a DECL_THREAD_LOCAL_P decl has NULL DECL_INITIAL and
> -fzero-initialized-in-bss (the default), we ICE starting with
> r251602, which changed bss_initializer_p:
> +  /* Do not put constants into the .bss section, they belong in a readonly
> +     section.  */
> +  return (!TREE_READONLY (decl)
> +	  &&
> to:
>           (DECL_INITIAL (decl) == NULL
>               /* In LTO we have no errors in program; error_mark_node is used
>                  to mark offlined constructors.  */
>               || (DECL_INITIAL (decl) == error_mark_node
>                   && !in_lto_p)
>               || (flag_zero_initialized_in_bss
>                   && initializer_zerop (DECL_INITIAL (decl))))
> Previously because bss_initializer_p for these returned true, ret was
> SECCAT_BSS and therefore we set it to SECCAT_TBSS as intended, but now ret
> is not SECCAT_BSS, but as TLS has only tbss and tdata possibilities, we
> still want to use tbss.  DECL_INITIAL NULL for a decl means implicit zero
> initialization.
> 
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?
> 
> 2017-09-05  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR middle-end/82095
> 	* varasm.c (categorize_decl_for_section): Use SECCAT_TBSS for TLS vars with
> 	NULL DECL_INITIAL.
> 
> 	* gcc.dg/tls/pr82095.c: New test.
THanks.  Sorry about the breakage.  TLS didn't even cross my mind.
Presumably the TLS initialization sections are readonly and copied into
the actual thread specific locations.

Jeff