Re: [Patch, AVR]: AVR backend cleanup: use elfos.h

[Georg-Johann Lay <avr at gjlay dot de>]

Denis Chertykov wrote:
> 2011/6/27 Georg-Johann Lay <avr@gjlay.de>:
>> This patch removes ELF dependencies from avr.h and redundancies from
>> avr.h and avr.c
>>
>> The AVR BE defines many things that are readily available in elfos.h.
>> ELF is the only target supported by avr-gcc.
>>
>> The patch includes elfos.h in config.gcc for all avr* targets together
>> with a new file avr/elf.h.
>>
>> ELF for avr deviates in some points from elfos.h. The needed overrides
>> are defined in avr/elf.h.  avr/elf.h is included after elfos.h because
>> that is the only way to achieve the needed overrides/undefs.
>>
>> The patch removes some hundreds lines from the AVR BE which are
>> redundant, and the new avr/elf.h makes it much clearer what the actual
>> deviations to default ELF implementation are.
>>
>> Some overrides like that there is no .ident emitted by avr presumably
>> have just historical reasons; anyway the patch tries to be neutral
>> compared to the present implementation.
>>
>> Same applies for other defines like READONLY_DATA_SECTION_ASM_OP:
>> .rodata is mapped to .data by avr ldscripts anyway, so there is
>> actually no need to set readonly_data_section = data_section and
>> merging of STRING_CST could save some space.
>>
>> For zeroes memory the patch will emit
>>   .zero N
>> instead of
>>   .skip N,0
>>
>> Tested without regressions and asm-output diffed for real-world avr-code.
>>
>> Johann
>>        * config.gcc (tm_file): Add elfos.h and avr/elf.h for
>>        avr-*-* and avr-*-rtems* targets.
>>
>>        * config/avr/elf.h: New file.
>>        (ASM_OUTPUT_BEFORE_CASE_LABEL): Define.
>>        (TARGET_ASM_SELECT_SECTION): Define.
>>        (INIT_SECTION_ASM_OP): Undefine.
>>        (FINI_SECTION_ASM_OP): Undefine.
>>        (IDENT_ASM_OP): Undefine.
>>        (ASM_OUTPUT_IDENT): Undefine.
>>        (READONLY_DATA_SECTION_ASM_OP): Undefine.
>>        (PCC_BITFIELD_TYPE_MATTERS): Undefine.
>>        (TARGET_HAVE_SWITCHABLE_BSS_SECTIONS): Undefine.
>>        * config/avr/avr.h:
>>        (PREFERRED_DEBUGGING_TYPE): Move to elf.h.
>>        (TARGET_ASM_NAMED_SECTION): Move to elf.h.
>>        (MAX_OFILE_ALIGNMENT): Move to elf.h.
>>        (STRING_LIMIT): Move to elf.h.
>>        (ASM_DECLARE_FUNCTION_NAME): Move to elf.h.
>>        (ASM_DECLARE_OBJECT_NAME): Remove.
>>        (ESCAPES): Remove.
>>        (ASM_OUTPUT_SKIP): Remove.
>>        (DWARF2_DEBUGGING_INFO): Remove.
>>        (OBJECT_FORMAT_ELF): Remove.
>>        (USER_LABEL_PREFIX): Remove.
>>        (ASM_OUTPUT_EXTERNAL): Remove.
>>        (ASM_OUTPUT_ASCII): Remove.
>>        (TYPE_ASM_OP): Remove.
>>        (SIZE_ASM_OP): Remove.
>>        (WEAK_ASM_OP): Remove.
>>        (STRING_ASM_OP): Remove.
>>        (SET_ASM_OP): Remove.
>>        (ASM_WEAKEN_LABEL): Remove.
>>        (TYPE_OPERAND_FMT): Remove.
>>        (ASM_DECLARE_FUNCTION_SIZE): Remove.
>>        (ASM_FINISH_DECLARE_OBJECT): Remove.
>>        (NO_DOLLAR_IN_LABEL): Remove.
>>        (ASM_GENERATE_INTERNAL_LABEL): Remove.
>>        (ASM_OUTPUT_CASE_LABEL): Remove.
>>        * config/avr/avr.c (avr_asm_output_aligned_decl_common): Use
>>        ASM_OUTPUT_ALIGNED_LOCAL, ASM_OUTPUT_ALIGNED_COMMON.
>>        (gas_output_ascii): Remove.
>>        (gas_output_limited_string): Remove.
>>        (TARGET_ASM_FILE_START_FILE_DIRECTIVE): Remove.
>>        * config/avr/avr-protos.h
>>        (gas_output_ascii): Remove prototye.
>>        (gas_output_limited_string): Remove prototype.
>>
> 
> Approved.
> 
> Denis.

http://gcc.gnu.org/ml/gcc-patches/2011-06/msg02011.html

Is that also for the config.gcc part?
Or does it need review from global reviewer?

Is there a specific reason not to emit .ident?
If not, I would remove the #undefs of IDENT_ASM_OP and
ASM_OUTPUT_IDENT from avr/elf.h.

Johann