Re: [PATCH] PR ld/19645: Properly implement STT_COMMON

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

On Mon, Feb 22, 2016 at 1:38 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> The BFD configure option, --enable-elf-stt-common, can't be to used to
> verify STT_COMMON implementation with the normal binutils build.  Instead,
> this patch removes it from BFD.  It adds --elf-stt-common=[no|yes] to ELF
> assembler/objcopy and adds -z common/-z nocommon to ld.
>
> A configure option, --enable-elf-stt-common, is added to gas to specify
> whether ELF assembler should generate common symbols with the STT_COMMON
> type by default.
>
> Since BSF_KEEP_G is never used, it is renamed to BSF_ELF_COMMON for ELF
> common symbols.
>
> Any comments?
>
> H.J.
> ---
> bfd/
>
>         PR ld/19645
>         * bfd.c (bfd): Change flags to 20 bits.
>         (BFD_CONVERT_ELF_COMMON): New.
>         (BFD_USE_ELF_STT_COMMON): Likewise.
>         (BFD_FLAGS_SAVED): Add BFD_CONVERT_ELF_COMMON and
>         BFD_USE_ELF_STT_COMMON.
>         (BFD_FLAGS_FOR_BFD_USE_MASK): Likewise.
>         * configure.ac: Remove --enable-elf-stt-common.
>         * elf.c (swap_out_syms): Choose STT_COMMON or STT_OBJECT for
>         common symbol depending on BFD_CONVERT_ELF_COMMON and
>         BFD_USE_ELF_STT_COMMON.
>         * elfcode.h (elf_slurp_symbol_table): Set BSF_ELF_COMMON for
>         STT_COMMON.
>         * elflink.c (bfd_elf_link_mark_dynamic_symbol): Also check
>         STT_COMMON.
>         (elf_link_convert_common_type): New function.
>         (elf_link_output_extsym): Choose STT_COMMON or STT_OBJECT for
>         common symbol depending on BFD_CONVERT_ELF_COMMON and
>         BFD_USE_ELF_STT_COMMON.  Set sym.st_info after sym.st_shndx.
>         * elfxx-target.h (TARGET_BIG_SYM): Add BFD_CONVERT_ELF_COMMON
>         and BFD_USE_ELF_STT_COMMON to object_flags.
>         (TARGET_LITTLE_SYM): Likewise.
>         * syms.c (BSF_KEEP_G): Renamed to ...
>         (BSF_ELF_COMMON): This.
>         * bfd-in2.h: Regenerated.
>         * config.in: Likewise.
>         * configure: Likewise.
>
> binutils/
>
>         PR ld/19645
>         * NEWS: Mention --elf-stt-common= for objcopy.
>         * doc/binutils.texi: Document --elf-stt-common= for objcopy.
>         * objcopy.c (do_elf_stt_common): New.
>         (command_line_switch): Add OPTION_ELF_STT_COMMON.
>         (copy_options): Add --elf-stt-common=.
>         (copy_usage): Add --elf-stt-common=.
>         (copy_object): Also check do_elf_stt_common for ELF targets.
>         (copy_file): Handle do_elf_stt_common.
>         (copy_main): Handle OPTION_ELF_STT_COMMON.
>         * readelf.c (apply_relocations): Support STT_COMMON.
>         * testsuite/binutils-all/common-1.s: New file.
>         * testsuite/binutils-all/common-1a.d: Likewise.
>         * testsuite/binutils-all/common-1b.d: Likewise.
>         * testsuite/binutils-all/common-1c.d: Likewise.
>         * testsuite/binutils-all/common-1d.d: Likewise.
>         * testsuite/binutils-all/common-1e.d: Likewise.
>         * testsuite/binutils-all/common-1f.d: Likewise.
>         * testsuite/binutils-all/common-2.s: Likewise.
>         * testsuite/binutils-all/common-2a.d: Likewise.
>         * testsuite/binutils-all/common-2b.d: Likewise.
>         * testsuite/binutils-all/common-2c.d: Likewise.
>         * testsuite/binutils-all/common-2d.d: Likewise.
>         * testsuite/binutils-all/common-2e.d: Likewise.
>         * testsuite/binutils-all/common-2f.d: Likewise.
>         * testsuite/binutils-all/objcopy.exp
>         (objcopy_test_elf_common_symbols): New proc.
>         Run objcopy_test_elf_common_symbols for ELF targets
>
> gas/
>
>         PR ld/19645
>         * NEWS: Mention --enable-elf-stt-common and --elf-stt-common=
>         for ELF assemblers.
>         * as.c (flag_use_elf_stt_common): New.
>         (show_usage): Add --elf-stt-common=.
>         (option_values): Add OPTION_ELF_STT_COMMON.
>         (std_longopts): Add --elf-stt-common=.
>         (parse_args): Handle --elf-stt-common=.
>         * as.h (flag_use_elf_stt_common): New.
>         * config.in: Regenerated.
>         * configure: Likewise.
>         * configure.ac: Add --enable-elf-stt-common and define
>         DEFAULT_GENERATE_ELF_STT_COMMON.
>         * gas/write.c (write_object_file): Set BFD_CONVERT_ELF_COMMON
>         and BFD_USE_ELF_STT_COMMON if flag_use_elf_stt_common is set.
>         * doc/as.texinfo: Document --elf-stt-common=.
>         * testsuite/gas/elf/common3.s: New file.
>         * testsuite/gas/elf/common3a.d: Likewise.
>         * testsuite/gas/elf/common3b.d: Likewise.
>         * testsuite/gas/elf/common4.s: Likewise.
>         * testsuite/gas/elf/common4a.d: Likewise.
>         * testsuite/gas/elf/common4b.d: Likewise.
>         * testsuite/gas/i386/dw2-compress-3b.d: Likewise.
>         * testsuite/gas/i386/dw2-compressed-3b.d: Likewise.
>         * testsuite/gas/elf/elf.exp: Run common3a, common3b, common4a
>         and common4b.
>         * testsuite/gas/i386/dw2-compress-3.d: Renamed to ...
>         * testsuite/gas/i386/dw2-compress-3a.d: This.  Pass
>         --elf-stt-common=no to as.
>         * testsuite/gas/i386/dw2-compressed-3.d: Renamed to ...
>         * testsuite/gas/i386/dw2-compressed-3a.d: This.  Pass
>         --elf-stt-common=no to as.
>         * testsuite/gas/i386/i386.exp: Run dw2-compress-3a,
>         dw2-compress-3b, dw2-compressed-3a and dw2-compressed-3b instead
>         of dw2-compress-3 and dw2-compressed-3.
>
> include/
>
>         PR ld/19645
>         * bfdlink.h (bfd_link_elf_stt_common): New enum.
>         (bfd_link_info): Add elf_stt_common.
>
> ld/
>
>         PR ld/19645
>         * NEWS: Mention -z common/-z nocommon for ELF targets.
>         * emultempl/elf32.em (gld${EMULATION_NAME}_handle_option): Handle
>         -z common and -z nocommon.
>         * ld.texinfo: Document -z common/-z nocommon.
>         * lexsup.c (elf_shlib_list_options): Add -z common/-z nocommon.
>         * testsuite/ld-elf/tls_common.exp: Test --elf-stt-common=no and
>         --elf-stt-common=yes with assembler.
>         * testsuite/ld-elfcomm/common-1.s: New file.
>         * testsuite/ld-elfcomm/common-1a.d: Likewise.
>         * testsuite/ld-elfcomm/common-1b.d: Likewise.
>         * testsuite/ld-elfcomm/common-1c.d: Likewise.
>         * testsuite/ld-elfcomm/common-1d.d: Likewise.
>         * testsuite/ld-elfcomm/common-1e.d: Likewise.
>         * testsuite/ld-elfcomm/common-1f.d: Likewise.
>         * testsuite/ld-elfcomm/common-2.s: Likewise.
>         * testsuite/ld-elfcomm/common-2a.d: Likewise.
>         * testsuite/ld-elfcomm/common-2b.d: Likewise.
>         * testsuite/ld-elfcomm/common-2c.d: Likewise.
>         * testsuite/ld-elfcomm/common-2d.d: Likewise.
>         * testsuite/ld-elfcomm/common-2e.d: Likewise.
>         * testsuite/ld-elfcomm/common-2f.d: Likewise.
>         * testsuite/ld-elfcomm/common-3a.rd: Likewise.
>         * testsuite/ld-elfcomm/common-3b.rd: Likewise.
>         * testsuite/ld-i386/pr19645.d: Likewise.
>         * testsuite/ld-i386/pr19645.s: Likewise.
>         * testsuite/ld-x86-64/pr19645.d: Likewise.
>         * testsuite/ld-x86-64/pr19645.s: Likewise.
>         * testsuite/ld-elfcomm/elfcomm.exp: Test --elf-stt-common=yes
>         with assembler.
>         (assembler_generates_commons): Removed.
>         Run -z common/-z nocommon tests.  Run *.d tests.
>         * testsuite/ld-i386/i386.exp: Run pr19645.
>         * testsuite/ld-x86-64/x86-64.exp: Likewise.
>         * testsuite/ld-x86-64/dwarfreloc.exp: Test --elf-stt-common with
>         assembler.  Test STT_COMMON with readelf.

This is the patch I am going to check in.



-- 
H.J.

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