[PATCH][GOLD] Make EXIDX sections work with ld -r

[=?big5?b?RG91ZyBLd2FuICjD9q62vHcp?= <dougkwan at google dot com>]

Hi

    This patch add code to make .ARM.exidx sections correctly linked
to their text sections in a relocatable link, which is used in the
kernel.  The patch also make the EXIDX section handling code more
robust in case of an error.  It also improve error reporting a bit by
printing the section name in an error message.  This patch is enough
to get stack unwinding working in the kernel but I believe the right
thing to do is to implement support for SHF_LINK_ORDER in gold.

-Doug


2010-07-13  Doug Kwan  <dougkwan@google.com>

        * arm.cc (Arm_input_section::Arm_input_section): For a
        SHT_ARM_EXIDX section, always keeps the input sections.
        (Arm_input_section::set_exidx_section_link): New method.
        (Arm_exidx_input_section::Arm_exidx_input_section): Initialize
        has_errors_ to false.
        (Arm_exidx_input_section::has_errors,
        Arm_exidx_input_section::set_has_errors): New methods.
        (Arm_exidx_input_section::has_errors_): New data member.
        (Arm_relobj::get_exidx_shndx_list): New method.
        (Arm_output_section::append_text_sections_to_list): Do not skip
        section without SHF_EXECINSTR.
        (Arm_output_section::fix_exidx_coverage): Skip input sections with
        errors.
        (Arm_relobj::make_exidx_input_section): Add new parameter for text
        section header.  Make error messages more verbose.  Check for
        a non-executable section linked to an EXIDX section.
        (Arm_relobj::do_read_symbols): Remove error checking, which has been
        moved to Arm_relobj::make_exidx_input_section.  Add an assertion to
        check that there is no deferred EXIDX section if we exit early.
        Instead of not making an EXIDX section in case of an error, make one
        and set the has_errors flag of it.
        (Target_arm::do_finalize_sections): Fix up links of EXIDX sections
        in a relocatable link.
        (Target_arm::do_relax): Look for the EXIDX output section instead of
        assuming that it is called .ARM.exidx.
        (Target_arm::fix_exidx_coverage): Add a new parameter for input
        section list.  Do not check for SHF_EXECINSTR section flags but
        skip any input section with errors.
        * output.cc (Output_section::Output_section): Initialize
        always_keeps_input_sections_ to false.
        (Output_section::add_input_section): Check for
        always_keeps_input_sections_.
        *  output.h (Output_section::always_keeps_input_sections,
        Output_section::set_always_keeps_input_sections): New methods.
        (Output_section::always_keeps_input_sections): New data member.

Attachment: patch-exidx.txt
Description: Text document