[Bug 1388999] Re: gdb is realy slow starting debugging.

[Matthias Klose]

is there a standalone test case for this issue? Also is this issue
reported upstream?  I can't see any Ubuntu specific patches which would
affect this.

** Changed in: gdb (Ubuntu)
       Status: New => Incomplete

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Title:
  gdb is realy slow starting debugging.

Status in “gdb” package in Ubuntu:
  Incomplete

Bug description:
  On binaries with a lot of symbols a massive performance degradation
  has happened between 14.04 and 14.10

  I have bisected the gdb performance degradation to this gdb commit

  commit 5840bf271c87c3fc14739173fdc91c6a14057130 (refs/bisect/bad)
  Author: H.J. Lu <hjl.tools at gmail.com>
  Date:   Wed Jul 16 17:16:24 2014

      Properly match PLT entry against .got.plt relocation
      
      Relocations against .got.plt section may not be in the same order as
      entries in PLT section.  It is incorrect to assume that the Ith reloction
      index against .got.plt section always maps to the (I + 1)th entry in PLT
      section.  This patch matches the .got.plt relocation offset/index in PLT
      entry against the index in .got.plt relocation table.  It only checks
      R_*_JUMP_SLOT and R_*_IRELATIVE relocations.  It ignores R_*_TLS_DESC
      and R_*_TLSDESC relocations since they have different PLT entries.
      
      bfd/
      
          PR binutils/17154
          * elf32-i386.c (elf_i386_plt_sym_val): Only match R_*_JUMP_SLOT
          and R_*_IRELATIVE relocation offset with PLT entry.
          * elf64-x86-64.c (elf_x86_64_plt_sym_val): Likewise.
          (elf_x86_64_plt_sym_val_offset_plt_bnd): New.
          (elf_x86_64_get_synthetic_symtab): Use it.
      
      ld/testsuite/
      
          PR binutils/17154
          * ld-ifunc/pr17154-i386.d: New file.
          * ld-ifunc/pr17154-x86-64.d: Likewise.
          * ld-ifunc/pr17154-x86.s: Likewise.
          * ld-x86-64/bnd-ifunc-2.d: Likewise.
          * ld-x86-64/bnd-ifunc-2.s: Likewise.
          * ld-x86-64/mpx.exp: Run bnd-ifunc-2.
          * ld-x86-64/tlsdesc-nacl.pd: Updated.
          * ld-x86-64/tlsdesc.pd: Likewise.

  ProblemType: Bug
  DistroRelease: Ubuntu 14.10
  Package: gdb 7.8-1ubuntu4
  ProcVersionSignature: Ubuntu 3.16.0-24.32-lowlatency 3.16.4
  Uname: Linux 3.16.0-24-lowlatency x86_64
  ApportVersion: 2.14.7-0ubuntu8
  Architecture: amd64
  CurrentDesktop: KDE
  Date: Mon Nov  3 23:27:53 2014
  InstallationDate: Installed on 2014-07-11 (115 days ago)
  InstallationMedia: Kubuntu 14.10 "Utopic Unicorn" - Alpha amd64 (20140710)
  SourcePackage: gdb
  UpgradeStatus: No upgrade log present (probably fresh install)

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