Re: [PATCH v2 2/4] gold: Correctly get and put r_info for Mips64el.

[Cary Coutant <ccoutant at gmail dot com>]

> elfcpp/
>         * elfcpp.h (class Rel): Add new constructor.
>         (class Rel_write): Likewise.
>         (class Rela): Likewise.
>         (class Rela_write): Likewise.
>         (Rela::get_r_info): Correctly get r_info for Mips64 little endian.
>         (Rela_write::put_r_info): Correctly put r_info for Mips64 little endian.
>
> gold/
>         * gc.h (gc_process_relocs): Call new constructor for Reltype.
>         * target-reloc.h (scan_relocs): Likewise.
>         (relocate_section): Likewise.
>         (scan_relocatable_relocs): Likewise.
>         (relocate_relocs): Call new constructor for Reltype and for Reltype_write.
>         * target.h (Target::is_mips64el): New virtual function.

I've taken a different approach. Rather than store a flag in the
elfcpp accessor class, which will have to be tested every time the
r_info field is accessed, I've extended the Classify_reloc interface
to provide methods for reading the r_sym and r_type fields. For the
templated routines in gc.h and target-reloc.h that use Classify_reloc
or Default_scan_relocatable_relocs, this allows us to provide the MIPS
accessor functions without a runtime check.

The commit description and ChangeLog entry are copied below. The patch
is attached.

-cary


For MIPS-64, the r_info field in the relocation format is
replaced by several individual fields, including r_sym and
r_type. To enable support for this format, I've refactored
target-independent code to remove almost all uses of the r_info
field. (I've left alone a couple of routines used only for
incremental linking, which I can update if/when the MIPS target
adds support for incremental linking.)

For routines that are already templated on a Classify_reloc class
(namely, gc_process_relocs, relocate_section, and
relocate_relocs), I've extended the Classify_reloc interface to
include sh_type (which no longer needs to be a separate template
parameter) as well as get_r_sym() and get_r_type() methods for
extracting the r_sym and r_type fields. For
scan_relocatable_relocs, I've extended the
Default_scan_relocatable_relocs class by converting it to a class
template with Classify_reloc as a template parameter. For the
remaining routines that need to access r_sym, I've added a
virtual Target::get_r_sym() method with an override for the MIPS
target.

In elfcpp, I've added Mips64_rel, etc., accessor classes and
corresponding internal data structures. The MIPS target uses
these new classes within its own Mips_classify_reloc class.
The Mips64_ accessor classes also expose the r_ssym, r_type2,
and r_type3 fields from the relocation.

These changes should be functionally the same for all but the
MIPS target.


2016-01-11  Cary Coutant  <ccoutant@gmail.com>

elfcpp/
        * elfcpp.h (Mips64_rel, Mips64_rel_write): New classes.
        (Mips64_rela, Mips64_rela_write): New classes.
        * elfcpp_internal.h (Mips64_rel_data, Mips64_rela_data): New structs.

gold/
        * gc.h (get_embedded_addend_size): Remove sh_type parameter.
        (gc_process_relocs): Remove sh_type template parameter.
        Use Classify_reloc to access r_sym, r_type, and r_addend fields.
        * object.h (Sized_relobj_file::split_stack_adjust): Add target
        parameter.
        (Sized_relobj_file::split_stack_adjust_reltype): Likewise.
        * reloc-types.h (Reloc_types::copy_reloc_addend): (SHT_REL and SHT_RELA
        specializations) Remove.
        * reloc.cc (Emit_relocs_strategy): Rename and move to target-reloc.h.
        (Sized_relobj_file::emit_relocs_scan): Call Target::emit_relocs_scan().
        (Sized_relobj_file::emit_relocs_scan_reltype): Remove.
        (Sized_relobj_file::split_stack_adjust): Add target parameter.
        Adjust all callers.
        (Sized_relobj_file::split_stack_adjust_reltype): Likewise. Call
        Target::get_r_sym() to get r_sym field from relocations.
        (Track_relocs::next_symndx): Call Target::get_r_sym().
        * target-reloc.h (scan_relocs): Remove sh_type template parameter;
        add Classify_reloc template parameter.  Use for accessing r_sym and
        r_type.
        (relocate_section): Likewise.
        (Default_classify_reloc): New class (renamed and moved from reloc.cc).
        (Default_scan_relocatable_relocs): Remove sh_type template parameter.
        (Default_scan_relocatable_relocs::Reltype): New typedef.
        (Default_scan_relocatable_relocs::reloc_size): New const.
        (Default_scan_relocatable_relocs::sh_type): New const.
        (Default_scan_relocatable_relocs::get_r_sym): New method.
        (Default_scan_relocatable_relocs::get_r_type): New method.
        (Default_emit_relocs_strategy): New class.
        (scan_relocatable_relocs): Replace sh_type template parameter with
        Scan_relocatable_relocs class.  Use it to access r_sym and r_type
        fields.
        (relocate_relocs): Replace sh_type template parameter with
        Classify_reloc class.  Use it to access r_sym and r_type fields.
        * target.h (Target::is_call_to_non_split): Replace r_type parameter
        with pointer to relocation. Adjust all callers.
        (Target::do_is_call_to_non_split): Likewise.
        (Target::emit_relocs_scan): New virtual method.
        (Sized_target::get_r_sym): New virtual method.
        * target.cc (Target::do_is_call_to_non_split): Replace r_type parameter
        with pointer to relocation.

        * aarch64.cc (Target_aarch64::emit_relocs_scan): New method.
        (Target_aarch64::Relocatable_size_for_reloc): Remove.
        (Target_aarch64::gc_process_relocs): Use Default_classify_reloc.
        (Target_aarch64::scan_relocs): Likewise.
        (Target_aarch64::relocate_section): Likewise.
        (Target_aarch64::Relocatable_size_for_reloc::get_size_for_reloc):
        Remove.
        (Target_aarch64::scan_relocatable_relocs): Use Default_classify_reloc.
        (Target_aarch64::relocate_relocs): Use Default_classify_reloc.
        * arm.cc (Target_arm::Arm_scan_relocatable_relocs): Remove sh_type
        template parameter.
        (Target_arm::emit_relocs_scan): New method.
        (Target_arm::Relocatable_size_for_reloc): Replace with...
        (Target_arm::Classify_reloc): ...this.
        (Target_arm::gc_process_relocs): Use Classify_reloc.
        (Target_arm::scan_relocs): Likewise.
        (Target_arm::relocate_section): Likewise.
        (Target_arm::scan_relocatable_relocs): Likewise.
        (Target_arm::relocate_relocs): Likewise.
        * i386.cc (Target_i386::emit_relocs_scan): New method.
        (Target_i386::Relocatable_size_for_reloc): Replace with...
        (Target_i386::Classify_reloc): ...this.
        (Target_i386::gc_process_relocs): Use Classify_reloc.
        (Target_i386::scan_relocs): Likewise.
        (Target_i386::relocate_section): Likewise.
        (Target_i386::scan_relocatable_relocs): Likewise.
        (Target_i386::relocate_relocs): Likewise.
        * mips.cc (Mips_scan_relocatable_relocs): Remove sh_type template
        parameter.
        (Mips_reloc_types): New class template.
        (Mips_classify_reloc): New class template.
        (Target_mips::Reltype): New typedef.
        (Target_mips::Relatype): New typedef.
        (Target_mips::emit_relocs_scan): New method.
        (Target_mips::get_r_sym): New method.
        (Target_mips::Relocatable_size_for_reloc): Replace with
        Mips_classify_reloc.
        (Target_mips::copy_reloc): Use Mips_classify_reloc.
        (Target_mips::gc_process_relocs): Likewise.
        (Target_mips::scan_relocs): Likewise.
        (Target_mips::relocate_section): Likewise.
        (Target_mips::scan_relocatable_relocs): Likewise.
        (Target_mips::relocate_relocs): Likewise.
        (mips_get_size_for_reloc): New function, factored out from
        Relocatable_size_for_reloc::get_size_for_reloc.
        (Target_mips::Scan::local): Use Mips_classify_reloc.
        (Target_mips::Scan::global): Likewise.
        (Target_mips::Relocate::relocate): Likewise.
        * powerpc.cc (Target_powerpc::emit_relocs_scan): New method.
        (Target_powerpc::Relocatable_size_for_reloc): Remove.
        (Target_powerpc::gc_process_relocs): Use Default_classify_reloc.
        (Target_powerpc::scan_relocs): Likewise.
        (Target_powerpc::relocate_section): Likewise.
        (Powerpc_scan_relocatable_reloc): Convert to class template.
        (Powerpc_scan_relocatable_reloc::Reltype): New typedef.
        (Powerpc_scan_relocatable_reloc::reloc_size): New const.
        (Powerpc_scan_relocatable_reloc::sh_type): New const.
        (Powerpc_scan_relocatable_reloc::get_r_sym): New method.
        (Powerpc_scan_relocatable_reloc::get_r_type): New method.
        (Target_powerpc::scan_relocatable_relocs): Use
        Powerpc_scan_relocatable_reloc.
        (Target_powerpc::relocate_relocs): Use Default_classify_reloc.
        * s390.cc (Target_s390::emit_relocs_scan): New method.
        (Target_s390::Relocatable_size_for_reloc): Remove.
        (Target_s390::gc_process_relocs): Use Default_classify_reloc.
        (Target_s390::scan_relocs): Likewise.
        (Target_s390::relocate_section): Likewise.
        (Target_s390::Relocatable_size_for_reloc::get_size_for_reloc):
        Remove.
        (Target_s390::scan_relocatable_relocs): Use Default_classify_reloc.
        (Target_s390::relocate_relocs): Use Default_classify_reloc.
        * sparc.cc (Target_sparc::emit_relocs_scan): New method.
        (Target_sparc::Relocatable_size_for_reloc): Remove.
        (Target_sparc::gc_process_relocs): Use Default_classify_reloc.
        (Target_sparc::scan_relocs): Likewise.
        (Target_sparc::relocate_section): Likewise.
        (Target_sparc::Relocatable_size_for_reloc::get_size_for_reloc):
        Remove.
        (Target_sparc::scan_relocatable_relocs): Use Default_classify_reloc.
        (Target_sparc::relocate_relocs): Use Default_classify_reloc.
        * tilegx.cc (Target_tilegx::emit_relocs_scan): New method.
        (Target_tilegx::Relocatable_size_for_reloc): Remove.
        (Target_tilegx::gc_process_relocs): Use Default_classify_reloc.
        (Target_tilegx::scan_relocs): Likewise.
        (Target_tilegx::relocate_section): Likewise.
        (Target_tilegx::Relocatable_size_for_reloc::get_size_for_reloc):
        Remove.
        (Target_tilegx::scan_relocatable_relocs): Use Default_classify_reloc.
        (Target_tilegx::relocate_relocs): Use Default_classify_reloc.
        * x86_64.cc (Target_x86_64::emit_relocs_scan): New method.
        (Target_x86_64::Relocatable_size_for_reloc): Remove.
        (Target_x86_64::gc_process_relocs): Use Default_classify_reloc.
        (Target_x86_64::scan_relocs): Likewise.
        (Target_x86_64::relocate_section): Likewise.
        (Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc):
        Remove.
        (Target_x86_64::scan_relocatable_relocs): Use Default_classify_reloc.
        (Target_x86_64::relocate_relocs): Use Default_classify_reloc.

        * testsuite/testfile.cc (Target_test::emit_relocs_scan): New method.

Attachment: mips-r-info.patch
Description: Binary data