[RFC PATCH, binutils, ELF 9/11] Add support for creating import libraries

[Nick Clifton]

Hi Thomas,

>> Please find an updated patch below.

>> *** bfd/ChangeLog ***
>>
>> 2016-02-17  Thomas Preud'homme  <thomas.preudhomme@arm.com>
>>
>>         * elf-bfd.h (elf_backend_filter_implib_symbols): Declare backend hook.
>>         (_bfd_elf_filter_global_symbols): Declare.
>>         * elf.c (_bfd_elf_filter_global_symbols): New function.
>>         * elflink.c (elf_filter_global_symbols): Likewise.
>>         (elf_output_implib): Likewise.
>>         (bfd_elf_final_link): Call above function, failing if it does.
>>         * elfxx-target.h (elf_backend_filter_implib_symbols): Define macro and
>>         default it to NULL.
>>         (elf_backend_copy_indirect_symbol): Fix spacing.
>>         (elf_backend_hide_symbol): Likewise.
>>         (elfNN_bed): Initialize elf_backend_filter_implib_symbols backend hook.
>>
>>
>> *** include/ChangeLog ***
>>
>> 2015-10-30  Thomas Preud'homme  <thomas.preudhomme@arm.com>
>>
>>         * bfdlink.h (struct bfd_link_info): Declare new ldscript_def and
>>         out_implib_bfd fields.
>>
>>
>> *** ld/ChangeLog ***
>>
>> 2015-11-02  Thomas Preud'homme  <thomas.preudhomme@arm.com>
>>
>>         * emultempl/elf32.em (gld${EMULATION_NAME}_after_open): Open import
>>         library file for writing and initialize implib_bfd field of link_info
>>         structure.
>>         * emultempl/pe.em (pe_implib_filename): Remove variable declaration.
>>         (OPTION_IMPLIB_FILENAME): Remove macro definition.
>>         (gld${EMULATION_NAME}_add_options): Remove --out-implib option.
>>         (gld_${EMULATION_NAME}_list_options): Likewise.
>>         (gld${EMULATION_NAME}_handle_option): Likewise.
>>         (gld_${EMULATION_NAME}_finish): Use command_line.out_implib_filename
>>         instead of pe_implib_filename.
>>         * emultempl/pep.em (pep_implib_filename): Remove variable declaration.
>>         (OPTION_IMPLIB_FILENAME): Remove enumerator.
>>         (gld${EMULATION_NAME}_add_options): Remove --out-implib option.
>>         (gld_${EMULATION_NAME}_list_options): Likewise.
>>         (gld${EMULATION_NAME}_handle_option): Likewise.
>>         (gld_${EMULATION_NAME}_finish): Use command_line.out_implib_filename
>>         instead of pep_implib_filename.
>>         * ld.h (args_type): Declare new out_implib_filename field.
>>         * ld.texinfo (--out-implib): Move documentation to arch-independent
>>         part and rephrase to apply to ELF targets.
>>         * ldexp.c (exp_fold_tree_1): Set ldscript_def field to 1 for symbols
>>         defined in linker scripts.
>>         * ldlex.h (enum option_values): Declare new OPTION_OUT_IMPLIB
>>         enumerator.
>>         * lexsup.c (ld_options): Add entry for new --out-implib switch.
>>         (parse_args): Handle OPTION_OUT_IMPLIB case.
>>
>>
>> *** ld/testsuite/ChangeLog ***
>>
>> 2015-10-30  Thomas Preud'homme  <thomas.preudhomme@arm.com>
>>
>>         * ld-elf/elf.exp (Generate empty import library): New test.
>>         (Generate import library): Likewise.
>>         * ld-elf/implib.s: Likewise.
>>         * ld-elf/implib.rd: New file.
>>         * ld-elf/empty-implib.out: Likewise
>>

Approved - please apply - but please could you add a line to the ld/NEWS 
file mentioning the new feature.

Also - I suspect that you will want this patch to go in to the 2.27 
release.  The decision is up to Tristan, but I would urge that it be
delayed until 2.28 as I think that it needs some time to bed-in, so to
speak.

Cheers
   Nick