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From: sergiodj+buildbot@redhat.com To: gdb-testers@sourceware.org Subject: [binutils-gdb] PowerPC64 thread-safe stubs not needed for iplt Date: Thu, 26 Feb 2015 17:59:00 -0000 [thread overview] Message-ID: <bd4d2eaad0f624bc47b2e27222480a44d1a48108@kwanyin> (raw) *** TEST RESULTS FOR COMMIT bd4d2eaad0f624bc47b2e27222480a44d1a48108 *** Author: Alan Modra <amodra@gmail.com> Branch: master Commit: bd4d2eaad0f624bc47b2e27222480a44d1a48108 PowerPC64 thread-safe stubs not needed for iplt I was looking at a current glibc using objdump today and saw an odd plt call stub. 0000000000044d80 <00000033.plt_call.__strchrnul>: 44d80: f8 41 00 28 std r2,40(r1) 44d84: e9 82 8c f8 ld r12,-29448(r2) 44d88: 7d 89 03 a6 mtctr r12 44d8c: e8 42 8d 00 ld r2,-29440(r2) 44d90: 28 22 00 00 cmpldi r2,0 44d94: 4c e2 04 20 bnectr+ 44d98: 48 13 84 f0 b 17d288 <realloc@plt> What? It doesn't branch to __strchrnul@plt on finding a zero r2? Turns out this isn't a real problem since the stub is for loading an ifunc, so will not be lazily resolved and thus r2 will never be zero. Of course, that means the thread-safety check is unnecessary. I also tweak the special __tls_get_addr_opt call stub here, to restore r2 immediately after the call. Not doing that might affect eh_frame unwinding. * elf64-ppc.c (plt_stub_size, build_plt_stub): Don't build thread-safe stubs for iplt. (build_tls_get_addr_stub): Restore r2 immediately after call.
next reply other threads:[~2015-02-26 16:34 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-02-26 17:59 sergiodj+buildbot [this message] 2015-02-26 18:16 ` Failures on Fedora-ppc64be-cc-with-index, branch master sergiodj+buildbot 2015-02-26 18:39 ` Failures on Fedora-ppc64be-native-gdbserver-m64, " sergiodj+buildbot 2015-02-26 22:07 ` Failures on Fedora-i686, " sergiodj+buildbot 2015-02-26 22:16 ` Failures on Fedora-x86_64-m32, " sergiodj+buildbot 2015-02-26 22:29 ` Failures on Fedora-x86_64-cc-with-index, " sergiodj+buildbot 2015-02-26 23:30 ` Failures on Fedora-x86_64-m64, " sergiodj+buildbot 2015-02-26 23:46 ` Failures on Fedora-x86_64-native-gdbserver-m32, " sergiodj+buildbot 2015-02-27 7:07 ` Failures on Debian-i686, " sergiodj+buildbot 2015-02-27 8:23 ` Failures on Debian-i686-native-gdbserver, " sergiodj+buildbot 2015-02-27 18:51 ` Failures on Debian-x86_64-native-gdbserver-m64, " sergiodj+buildbot
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