Re: PING: PATCH: PR target/46770: Use .init_array/.fini_array sections

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

PING.

On Sat, Aug 6, 2011 at 7:40 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> PING.
>
> On Fri, Jul 22, 2011 at 7:06 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Fri, Jul 22, 2011 at 7:00 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Fri, Jul 22, 2011 at 6:03 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>> On Fri, Jul 22, 2011 at 5:30 AM, Jakub Jelinek <jakub@redhat.com> wrote:
>>>>> On Fri, Jul 22, 2011 at 04:59:28AM -0700, H.J. Lu wrote:
>>>>>> @@ -2660,6 +2664,7 @@ esac
>>>>>>  case ${target} in
>>>>>>  i[34567]86-*-linux* | x86_64-*-linux*)
>>>>>>       tmake_file="${tmake_file} i386/t-pmm_malloc i386/t-i386"
>>>>>> +     use_initfini_array=yes
>>>>>>       ;;
>>>>>>  i[34567]86-*-* | x86_64-*-*)
>>>>>>       tmake_file="${tmake_file} i386/t-gmm_malloc i386/t-i386"
>>>>>
>>>>> What is i?86/x86_64 specific on it?  Don't most other glibc targets
>>>>> want to use it too, perhaps with some arch specific tweaks?
>>>>
>>>> I do have a patch for all ELF targets:
>>>>
>>>> http://gcc.gnu.org/ml/gcc-patches/2011-06/msg01416.html
>>>>
>>>> It touches many targets. .  But I only have one feedback from one
>>>> target maintainer.  I don't know how long it will take to review it.
>>>>
>>>>
>>>>>> --- /dev/null
>>>>>> +++ b/gcc/config/initfini-array.c
>>>>>
>>>>> This is ugly.  varasm.c already has lots of ELF specific code, simply
>>>>> put them there as well and only let configury set some macro which will
>>>>> allow targets to choose which of the implementations in the generic code
>>>>> they want to use (or if they want their own which e.g. calls the generic
>>>>> routine and does something additional to it etc.).  The sections probably
>>>>> can be created only the first time you actually need them.
>>>>
>>>> I will do that.
>>>>
>>>>>> --- a/gcc/crtstuff.c
>>>>>> +++ b/gcc/crtstuff.c
>>>>>> @@ -189,6 +190,9 @@ typedef void (*func_ptr) (void);
>>>>>>     refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__
>>>>>>     symbol in crtbegin.o, where they are defined.  */
>>>>>>
>>>>>> +/* No need for .ctors/.dtors section if linker can place them in
>>>>>> +   .init_array/.fini_array section.  */
>>>>>> +#ifndef NO_CTORS_DTORS_SECTIONS
>>>>>>  /* The -1 is a flag to __do_global_[cd]tors indicating that this table
>>>>>>     does not start with a count of elements.  */
>>>>>>  #ifdef CTOR_LIST_BEGIN
>>>>>> @@ -219,6 +223,7 @@ STATIC func_ptr __DTOR_LIST__[1]
>>>>>>    __attribute__((section(".dtors"), aligned(sizeof(func_ptr))))
>>>>>>    = { (func_ptr) (-1) };
>>>>>>  #endif /* __DTOR_LIST__ alternatives */
>>>>>> +#endif /* NO_CTORS_DTORS_SECTIONS */
>>>>>>
>>>>>>  #ifdef USE_EH_FRAME_REGISTRY
>>>>>>  /* Stick a label at the beginning of the frame unwind info so we can register
>>>>>> @@ -489,6 +494,9 @@ __do_global_ctors_1(void)
>>>>>>
>>>>>>  #elif defined(CRT_END) /* ! CRT_BEGIN */
>>>>>>
>>>>>> +/* No need for .ctors/.dtors section if linker can place them in
>>>>>> +   .init_array/.fini_array section.  */
>>>>>> +#ifndef NO_CTORS_DTORS_SECTIONS
>>>>>>  /* Put a word containing zero at the end of each of our two lists of function
>>>>>>     addresses.  Note that the words defined here go into the .ctors and .dtors
>>>>>>     sections of the crtend.o file, and since that file is always linked in
>>>>>> @@ -534,6 +542,7 @@ STATIC func_ptr __DTOR_END__[1]
>>>>>>    __attribute__((used, section(".dtors"), aligned(sizeof(func_ptr))))
>>>>>>    = { (func_ptr) 0 };
>>>>>>  #endif
>>>>>> +#endif /* NO_CTORS_DTORS_SECTIONS */
>>>>>>
>>>>>>  #ifdef EH_FRAME_SECTION_NAME
>>>>>>  /* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
>>>>>
>>>>> I don't see how you can do this.  It would IMO break any time you link code
>>>>> built by different gcc versions where some code emitted by the older gcc
>>>>> used .ctors or .dtors.
>>>>
>>>> crtstuff.c is used to generate crt*.o, which is the part of GCC.  You only use
>>>> it with the GCC you are using.  Since your GCC doesn't put anything in
>>>> .ctors/.dtors section, you don't need them.  As for .o files generated by
>>>> old GCCs, that is the linker test, use_initfini_array, is for.  The newer linker
>>>> can put input .ctors/.dtors sections in output .init_array/,fini_array sections.
>>>>
>>>>
>>>
>>> Here is the updated patch.  Any comments?
>>>
>>> Thanks.
>>>
>>> --
>>> H.J.
>>> ---
>>> 2011-07-22  H.J. Lu  <hongjiu.lu@intel.com>
>>>
>>>        PR target/46770
>>>        * config.gcc (use_initfini_array): New variable.
>>>        Use .init_arary/.fini_array if they are supported.
>>>
>>>        * crtstuff.c: Don't generate .ctors nor .dtors sections if
>>>        USE_INITFINI_ARRAY is defined.
>>>
>>>        * output.h (default_initfini_array_init_sections): New.
>>>        * varasm.c (elf_init_array_section): Likewise.
>>>        (elf_fini_array_section): Likewise.
>>>        (get_elf_initfini_array_priority_section): Likewise.
>>>        (default_elf_init_array_asm_out_constructor): Likewise.
>>>        (default_elf_fini_array_asm_out_destructor): Likewise.
>>>        (default_initfini_array_init_sections): Likewise.
>>>
>>>        * config/initfini-array.h: New.
>>>        * config/t-initfini-array: Likewise.
>>>
>>
>> No need for config/t-initfini-array.  Here is the updated patch.
>>
>>
>> --
>> H.J.
>> ----
>> 2011-07-22  H.J. Lu  <hongjiu.lu@intel.com>
>>
>>        PR target/46770
>>        * config.gcc (use_initfini_array): New variable.
>>        Use .init_arary/.fini_array if they are supported.
>>
>>        * crtstuff.c: Don't generate .ctors nor .dtors sections if
>>        USE_INITFINI_ARRAY is defined.
>>
>>        * output.h (default_initfini_array_init_sections): New.
>>        * varasm.c (elf_init_array_section): Likewise.
>>        (elf_fini_array_section): Likewise.
>>        (get_elf_initfini_array_priority_section): Likewise.
>>        (default_elf_init_array_asm_out_constructor): Likewise.
>>        (default_elf_fini_array_asm_out_destructor): Likewise.
>>        (default_initfini_array_init_sections): Likewise.
>>
>>        * config/initfini-array.h: New.
>>
>>        * config/arm/arm.c (arm_asm_init_sections): Call
>>        default_initfini_array_init_sections.
>>        * config/avr/avr.c (avr_asm_init_sections): Likewise.
>>        * config/ia64/ia64.c (ia64_asm_init_sections): Likewise.
>>        * config/mep/mep.c (mep_asm_init_sections): Likewise.
>>        * config/microblaze/microblaze.c (microblaze_elf_asm_init_sections):
>>        Likewise.
>>        * config/rs6000/rs6000.c (rs6000_elf_asm_init_sections): Likewise.
>>        * config/stormy16/stormy16.c (xstormy16_asm_init_sections):
>>        Likewise.
>>        * config/v850/v850.c (v850_asm_init_sections): Likewise.
>>
>
>
>
> --
> H.J.
>



-- 
H.J.