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[Bug dynamic-link/22093] ld.so no longer searches in .../x86_64


https://sourceware.org/bugzilla/show_bug.cgi?id=22093

--- Comment #6 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
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The branch, hjl/pr21265/2.26 has been created
        at  5d9b05d1ad4faa68f82e80dee014df7d5f9872c3 (commit)

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=5d9b05d1ad4faa68f82e80dee014df7d5f9872c3

commit 5d9b05d1ad4faa68f82e80dee014df7d5f9872c3
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Mar 23 08:21:52 2017 -0700

    x86-64: Use fxsave/xsave/xsavec in _dl_runtime_resolve [BZ #21265]

    In _dl_runtime_resolve, use fxsave/xsave/xsavec to preserve all vector,
    mask and bound registers.  It simplifies _dl_runtime_resolve and supports
    different calling conventions.  ld.so code size is reduced by more than
    1 KB.  However, use fxsave/xsave/xsavec takes a little bit more cycles
    than saving and restoring vector and bound registers individually.

    Latency for _dl_runtime_resolve to lookup the function, foo, from one
    shared library plus libc.so:

                                 Before    After     Change

    Westmere (SSE)/fxsave         345      866       151%
    IvyBridge (AVX)/xsave         420      643       53%
    Haswell (AVX)/xsave           713      1252      75%
    Skylake (AVX+MPX)/xsavec      559      719       28%
    Skylake (AVX512+MPX)/xsavec   145      272       87%
    Ryzen (AVX)/xsavec            280      553       97%

    This is the worst case where portion of time spent for saving and
    restoring registers is bigger than majority of cases.  With smaller
    _dl_runtime_resolve code size, overall performance impact is negligible.

    On IvyBridge, differences in build and test time of binutils with lazy
    binding GCC and binutils are noises.  On Westmere, differences in
    bootstrap and "makc check" time of GCC 7 with lazy binding GCC and
    binutils are also noises.

        [BZ #21265]
        * sysdeps/x86/cpu-features-offsets.sym (XSAVE_STATE_SIZE_OFFSET):
        New.
        * sysdeps/x86/cpu-features.c: Include <libc-pointer-arith.h>.
        (get_common_indeces): Set xsave_state_size, xsave_state_full_size
        and bit_arch_XSAVEC_Usable if needed.
        (init_cpu_features): Remove bit_arch_Use_dl_runtime_resolve_slow
        and bit_arch_Use_dl_runtime_resolve_opt.
        * sysdeps/x86/cpu-features.h (bit_arch_Use_dl_runtime_resolve_opt):
        Removed.
        (bit_arch_Use_dl_runtime_resolve_slow): Likewise.
        (bit_arch_Prefer_No_AVX512): Updated.
        (bit_arch_MathVec_Prefer_No_AVX512): Likewise.
        (bit_arch_XSAVEC_Usable): New.
        (STATE_SAVE_OFFSET): Likewise.
        (STATE_SAVE_MASK): Likewise.
        [__ASSEMBLER__]: Include <cpu-features-offsets.h>.
        (cpu_features): Add xsave_state_size and xsave_state_full_size.
        (index_arch_Use_dl_runtime_resolve_opt): Removed.
        (index_arch_Use_dl_runtime_resolve_slow): Likewise.
        (index_arch_XSAVEC_Usable): New.
        * sysdeps/x86/cpu-tunables.c (TUNABLE_CALLBACK (set_hwcaps)):
        Support XSAVEC_Usable.  Remove Use_dl_runtime_resolve_slow.
        * sysdeps/x86_64/Makefile (tst-x86_64-1-ENV): New if tunables
        is enabled.
        * sysdeps/x86_64/dl-machine.h (elf_machine_runtime_setup):
        Replace _dl_runtime_resolve_sse, _dl_runtime_resolve_avx,
        _dl_runtime_resolve_avx_slow, _dl_runtime_resolve_avx_opt,
        _dl_runtime_resolve_avx512 and _dl_runtime_resolve_avx512_opt
        with _dl_runtime_resolve_fxsave, _dl_runtime_resolve_xsave and
        _dl_runtime_resolve_xsavec.
        * sysdeps/x86_64/dl-trampoline.S (DL_RUNTIME_UNALIGNED_VEC_SIZE):
        Removed.
        (DL_RUNTIME_RESOLVE_REALIGN_STACK): Check STATE_SAVE_ALIGNMENT
        instead of VEC_SIZE.
        (REGISTER_SAVE_BND0): Removed.
        (REGISTER_SAVE_BND1): Likewise.
        (REGISTER_SAVE_BND3): Likewise.
        (REGISTER_SAVE_RAX): Always defined to 0.
        (VMOV): Removed.
        (_dl_runtime_resolve_avx): Likewise.
        (_dl_runtime_resolve_avx_slow): Likewise.
        (_dl_runtime_resolve_avx_opt): Likewise.
        (_dl_runtime_resolve_avx512): Likewise.
        (_dl_runtime_resolve_avx512_opt): Likewise.
        (_dl_runtime_resolve_sse): Likewise.
        (_dl_runtime_resolve_sse_vex): Likewise.
        (USE_FXSAVE): New.
        (_dl_runtime_resolve_fxsave): Likewise.
        (USE_XSAVE): Likewise.
        (_dl_runtime_resolve_xsave): Likewise.
        (USE_XSAVEC): Likewise.
        (_dl_runtime_resolve_xsavec): Likewise.
        * sysdeps/x86_64/dl-trampoline.h (_dl_runtime_resolve_avx512):
        Removed.
        (_dl_runtime_resolve_avx512_opt): Likewise.
        (_dl_runtime_resolve_avx): Likewise.
        (_dl_runtime_resolve_avx_opt): Likewise.
        (_dl_runtime_resolve_sse): Likewise.
        (_dl_runtime_resolve_sse_vex): Likewise.
        (_dl_runtime_resolve_fxsave): New.
        (_dl_runtime_resolve_xsave): Likewise.
        (_dl_runtime_resolve_xsavec): Likewise.

    (cherry picked from commit b52b0d793dcb226ecb0ecca1e672ca265973233c)

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=aca8619adb0e5d96f6e7d821d39adc6cca6d6c55

commit aca8619adb0e5d96f6e7d821d39adc6cca6d6c55
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Sep 11 08:18:11 2017 -0700

    x86: Add x86_64 to x86-64 HWCAP [BZ #22093]

    Before glibc 2.26, ld.so set dl_platform to "x86_64" and searched the
    "x86_64" subdirectory when loading a shared library.  ld.so in glibc
    2.26 was changed to set dl_platform to "haswell" or "xeon_phi", based
    on supported ISAs.  This led to shared library loading failure for
    shared libraries placed under the "x86_64" subdirectory.

    This patch adds "x86_64" to x86-64 dl_hwcap so that ld.so will always
    search the "x86_64" subdirectory when loading a shared library.

    NB: We can't set x86-64 dl_platform to "x86-64" since ld.so will skip
    the "haswell" and "xeon_phi" subdirectories on "haswell" and "xeon_phi"
    machines.

    Tested on i686 and x86-64.

        [BZ #22093]
        * sysdeps/x86/cpu-features.c (init_cpu_features): Initialize
        GLRO(dl_hwcap) to HWCAP_X86_64 for x86-64.
        * sysdeps/x86/dl-hwcap.h (HWCAP_COUNT): Updated.
        (HWCAP_IMPORTANT): Likewise.
        (HWCAP_X86_64): New enum.
        (HWCAP_X86_AVX512_1): Updated.
        * sysdeps/x86/dl-procinfo.c (_dl_x86_hwcap_flags): Add "x86_64".
        * sysdeps/x86_64/Makefile (tests): Add tst-x86_64-1.
        (modules-names): Add x86_64/tst-x86_64mod-1.
        (LDFLAGS-tst-x86_64mod-1.so): New.
        ($(objpfx)tst-x86_64-1): Likewise.
        ($(objpfx)x86_64/tst-x86_64mod-1.os): Likewise.
        (tst-x86_64-1-clean): Likewise.
        * sysdeps/x86_64/tst-x86_64-1.c: New file.
        * sysdeps/x86_64/tst-x86_64mod-1.c: Likewise.

    (cherry picked from commit 45ff34638f034877b6a490c217d6a0632ce263f4)

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