Re: [PATCH] i386: Access external function via GOT slot for -fno-plt

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Thu, Jun 23, 2016 at 9:23 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Thu, Jun 23, 2016 at 6:08 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>
>> Here is the updated patch.  OK for trunk?
>>
>> PR target/66232
>> PR target/67400
>> * configure.ac (as_ix86_tls_ldm_opt): Renamed to ...
>> (as_ix86_gas_opt): This.
>> (ld_ix86_tls_ldm_opt): Renamed to ...
>> (ld_ix86_gld_opt): This.
>> (R_386_TLS_LDM reloc): Updated.
>> (R_386_GOT32X reloc): New assembler/linker check.
>> (HAVE_AS_IX86_GOT32X): New.  Defined to 1 if 32-bit assembler and
>> linker support "jmp *_start@GOT" and "cmpl $0, bar@GOT".  Otherise,
>> defined to 0.
>> * config.in: Regenerated.
>> * configure: Likewise.
>> * config/i386/i386.c (ix86_force_load_from_GOT_p): Return
>> true if HAVE_AS_IX86_GOT32X is 1 in 32-bit mode.
>> (ix86_legitimate_address_p): Allow UNSPEC_GOT for -fno-plt
>> if ix86_force_load_from_GOT_p returns true.
>> (ix86_print_operand_address_as): Also support UNSPEC_GOT if
>> ix86_force_load_from_GOT_p returns true.
>> (ix86_expand_move): Generate UNSPEC_GOT in 32-bit mode to load
>> the external function address via the GOT slot.
>> (ix86_nopic_noplt_attribute_p): Check both TARGET_64BIT and
>> HAVE_AS_IX86_GOT32X before returning false.
>> (ix86_output_call_insn): Generate "%!jmp/call\t*%p0@GOT" in
>> 32-bit mode if ix86_nopic_noplt_attribute_p returns true.
>>
>> gcc/testsuite/
>>
>> PR target/66232
>> PR target/67400
>> * gcc.target/i386/pr66232-14.c: New file.
>> * gcc.target/i386/pr66232-15.c: Likewise.
>> * gcc.target/i386/pr66232-16.c: Likewise.
>> * gcc.target/i386/pr66232-17.c: Likewise.
>> * gcc.target/i386/pr67400-1.c: Don't disable for ia32.  Scan for
>> ia32 if R_386_GOT32X relocation is supported.
>> * gcc.target/i386/pr67400-2.c: Likewise.
>> * gcc.target/i386/pr67400-3.c: Likewise.
>> * gcc.target/i386/pr67400-4.c: Likewise.
>> * gcc.target/i386/pr67400-6.c: Likewise.
>> * gcc.target/i386/pr67400-7.c: Likewise.
>> * lib/target-supports.exp (check_effective_target_got32x_reloc):
>> New.
>
> OK with a nit below.
>
> Thanks,
> Uros.
>
> --- a/gcc/configure.ac
> +++ b/gcc/configure.ac
> @@ -4164,13 +4164,13 @@ tls_ld:
>
>      # Enforce 32-bit output with gas and gld.
>      if test x$gas = xyes; then
> -      as_ix86_tls_ldm_opt="--32"
> +      as_ix86_gas_opt="--32"
>      fi
>      if echo "$ld_ver" | grep GNU > /dev/null; then
>        if $gcc_cv_ld -V 2>/dev/null | grep elf_i386_sol2 > /dev/null; then
> -        ld_ix86_tls_ldm_opt="-melf_i386_sol2"
> +        ld_ix86_gld_opt="-melf_i386_sol2"
>        else
> -        ld_ix86_tls_ldm_opt="-melf_i386"
> +        ld_ix86_gld_opt="-melf_i386"
>        fi
>      fi
>      conftest_s='
>
> I'd like to suggest better names, perhaps as_ix86_gas_32_opt and
> ld_ix86_gld_32_opt to mark that they are intended for 32bit targets.
> But it is up to you, we can also live with above names.

I checked it with the name change suggested above.

Thanks.


-- 
H.J.