[4.5.1,PR42776] Backport LTO-COFF implementation.

[Richard Guenther]

On Sat, Jun 12, 2010 at 10:17 AM, Richard Guenther
<richard.guenther@gmail.com> wrote:
> On Sat, Jun 12, 2010 at 5:05 AM, Dave Korn <dave.korn.cygwin@gmail.com> wrote:
>>
>>    Hi list,
>>
>>  The attached patch backports the LTO-COFF implementation from mainline to
>> 4.5 branch, as we discussed at the time it was committed to trunk.
>>
>> ChangeLog:
>>
>>  Backport from mainline:
>>  2010-04-27  Dave Korn  <dave.korn.cygwin@gmail.com>
>>
>>        PR lto/42776
>>        * configure.ac (--enable-lto): Refactor handling so libelf tests
>>        are only performed inside then-clause of ACX_ELF_TARGET_IFELSE,
>>        and allow LTO to be explicitly enabled on non-ELF platforms that
>>        are known to support it inside else-clause.
>>        * configure: Regenerate.
>>
>> gcc/ChangeLog:
>>
>>  Backport from mainline:
>>  2010-04-27  Dave Korn  <dave.korn.cygwin@gmail.com>
>>
>>        PR lto/42776
>>        * configure.ac (gcc_cv_as_section_has_align): Set if installed
>>        binutils supports extended .section directive needed by LTO, or
>>        warn if older binutils found.
>>        (LTO_BINARY_READER): New AC_SUBST'd variable.
>>        (LTO_USE_LIBELF): Likewise.
>>        * config.gcc (lto_binary_reader): New target-specific configure
>>        variable.
>>        * Makefile.in (LTO_BINARY_READER): Import AC_SUBST'd autoconf var.
>>        (LTO_USE_LIBELF): Likewise.
>>        * configure: Regenerate.
>>        * collect2.c (is_elf): Rename from this ...
>>        (is_elf_or_coff): ... to this, and recognize and allow i386 COFF
>>         object files in addition to ELF-formatted ones.
>>        (scan_prog_file): Caller updated.  Also allow for LTO info marker
>>        symbol to be prefixed or not by an extra underscore.
>>        * config/i386/t-cygming (winnt.o): Also depend on LTO_STREAMER_H.
>>        * config/i386/winnt.c: Also #include lto-streamer.h
>>        (i386_pe_asm_named_section): Specify 1-byte section alignment for
>>        LTO named sections.
>>        (i386_pe_asm_output_aligned_decl_common): Add comment.
>>        (i386_pe_maybe_record_exported_symbol): Allow decl arg to be NULL.
>>
>> gcc/lto/ChangeLog:
>>
>>  Backport from mainline:
>>  2010-04-27  Dave Korn  <dave.korn.cygwin@gmail.com>
>>
>>        PR lto/42776
>>        * Make-lang.in (LTO_OBJS): Use LTO_BINARY_READER instead of
>>        hardcoding 'lto-elf.o'.
>>        ($(LTO_EXE)): Use LTO_USE_LIBELF instead of hardcoding '-lelf'.
>>        * lto-coff.h: New file.
>>        * lto-coff.c: Likewise.
>>
>>  2010-04-26  Dave Korn  <dave.korn.cygwin@gmail.com>
>>
>>        * lto.h (lto_elf_file_open): Rename prototype from this ...
>>        (lto_obj_file_open): ... to this.
>>        (lto_elf_file_close): Likewise ...
>>        (lto_obj_file_close): ... and likewise.
>>        (lto_elf_build_section_table): Likewise ...
>>        (lto_obj_build_section_table): ... and likewise.
>>        (lto_elf_begin_section): Likewise ...
>>        (lto_obj_begin_section): ... and likewise.
>>        (lto_elf_append_data): Likewise ...
>>        (lto_obj_append_data): ... and likewise.
>>        (lto_elf_end_section): Likewise ...
>>        (lto_obj_end_section): ... and likewise.
>>        * lto.c (lto_file_read): Update references to the above.
>>        (lto_wpa_write_files): Likewise.
>>        (lto_read_all_file_options): Likewise.
>>        (read_cgraph_and_symbols): Likewise.
>>        * lto-lang.c (LANG_HOOKS_BEGIN_SECTION): Likewise.
>>        (LANG_HOOKS_APPEND_DATA): Likewise.
>>        (LANG_HOOKS_END_SECTION): Likewise.
>>        * lto-elf.c (lto_elf_file_open): Rename from this ...
>>        (lto_obj_file_open): ... to this, updating any references.
>>        (lto_elf_file_close): Likewise ...
>>        (lto_obj_file_close): ... and likewise.
>>        (lto_elf_build_section_table): Likewise ...
>>        (lto_obj_build_section_table): ... and likewise.
>>        (lto_elf_begin_section): Likewise ...
>>        (lto_obj_begin_section): ... and likewise.
>>        (lto_elf_append_data): Likewise ...
>>        (lto_obj_append_data): ... and likewise.
>>        (lto_elf_end_section): Likewise ...
>>        (lto_obj_end_section): ... and likewise.
>>
>>
>>  Bootstrapped and tests running on i686-pc-cygwin; ok for branch if (when) no
>> regressions?
>
> Ok.  If you did the backport by applying the respective trunk revisions can
> you after the commit diff the 4.5 variants of the new files to the trunk
> variant to see if there are other fixes worth backporting?
>
> Can you also post your testresults to gcc-testresults?

Oh, and add an entry to gcc-4.5/changes.html to the section for 4.5.1.

> Thanks,
> Richard.
>
>>    cheers,
>>      DaveK
>>
>>
>>
>