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[Bug ld/22263] -fpie -pie generates dynamic relocations in text section

From: cvs-commit at gcc dot gnu.org
Subject: [Bug ld/22263] -fpie -pie generates dynamic relocations in text section
Date: Tue, 27 Nov 2018 12:43:38 +0000


--- Comment #18 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot 
gnu.org> ---
The master branch has been updated by Tamar Christina


commit 9fca35fc3486283562a7fcd9eb0ff845b0152d98
Author: Tamar Christina <address@hidden>
Date:   Tue Nov 27 12:33:21 2018 +0000

    AArch64: Fix regression in Cortex A53 erratum when PIE. (PR ld/23904)

    The fix for PR ld/22263 causes TLS relocations using ADRP to be relaxed
    into MOVZ, however this causes issues for the erratum code.

    The erratum code scans the input sections looking for ADRP instructions
    and notes their location in the stream.

    It then later tries to find them again in order to generate the linker
    stubs.  Due to the relaxation it instead finds a MOVZ and hard aborts.

    Since this relaxation is a valid one, and in which case the erratum no
    longer applies, it shouldn't abort but instead just continue.

    This changes the TLS relaxation code such that when it finds an ADRP and
    it relaxes it, it removes the erratum entry from the work list by changing
    the stub type into none so the stub is ignored.

    The entry is not actually removed as removal is a more expensive operation
    and we have already allocated the memory anyway.

    The clearing is done for IE->LE and GD->LE relaxations, and a testcase is
    added for the IE case. The GD case I believe to be impossible to get
    with the erratum sequence due to the required BL which would break the
    However to cover all basis I have added the guard there as well.

    build on native hardware and regtested on
      aarch64-none-elf, aarch64-none-elf (32 bit host),
      aarch64-none-linux-gnu, aarch64-none-linux-gnu (32 bit host)

    Cross-compiled and regtested on
      aarch64-none-linux-gnu, aarch64_be-none-linux-gnu

    Testcase in PR23940 tested and works as expected now and benchmarks ran on
    showing no regressions and no issues.


        PR ld/23904
        * elfnn-aarch64.c (_bfd_aarch64_adrp_p): Use existing constants.
        (_bfd_aarch64_erratum_843419_branch_to_stub): Use _bfd_aarch64_adrp_p.
        (struct erratum_835769_branch_to_stub_clear_data): New.
        (_bfd_aarch64_erratum_843419_clear_stub): New.
        (clear_erratum_843419_entry): New.
        (elfNN_aarch64_tls_relax): Use it.
        (elfNN_aarch64_relocate_section): Pass input_section.
        (aarch64_map_one_stub): Handle branch type none as valid.


        PR ld/23904
        * testsuite/ld-aarch64/aarch64-elf.exp: Add erratum843419_tls_ie.
        * testsuite/ld-aarch64/erratum843419_tls_ie.d: New test.
        * testsuite/ld-aarch64/erratum843419_tls_ie.s: New test.

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