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Yao Qi 42d38f42dc Skip gdb.base/relativedebug.exp if libc doesn't have debug info
Hi,
I see the fail in gdb.base/relativedebug.exp on aarch64 box on which
glibc doesn't have debug info,

 bt^M
 #0 0x0000002000061a88 in raise () from /lib/aarch64-linux-gnu/libc.so.6^M
 #1 0x0000002000064efc in abort () from /lib/aarch64-linux-gnu/libc.so.6^M
 #2 0x0000000000400640 in handler (signo=14) at ../../../binutils-gdb/gdb/testsuite/gdb.base/relativedebug.c:25^M
 #3 <signal handler called>^M
 #4 0x00000020000cc478 in ?? () from /lib/aarch64-linux-gnu/libc.so.6^M
 #5 0x0000000000400664 in main () at ../../../binutils-gdb/gdb/testsuite/gdb.base/relativedebug.c:32^M
 (gdb) FAIL: gdb.base/relativedebug.exp: pause found in backtrace

if glibc has debug info, this test doesn't fail.

In sysdeps/unix/sysv/linux/generic/pause.c, __libc_pause calls
__syscall_pause,

  static int
  __syscall_pause (void)
  {
    sigset_t set;

    int rc =
      INLINE_SYSCALL (rt_sigprocmask, 4, SIG_BLOCK, NULL, &set, _NSIG / 8);
    if (rc == 0)
      rc = INLINE_SYSCALL (rt_sigsuspend, 2, &set, _NSIG / 8);

    return rc;
  }

  int
  __libc_pause (void)
  {
    if (SINGLE_THREAD_P)
      return __syscall_pause ();     <--- tail call

    int oldtype = LIBC_CANCEL_ASYNC ();

    int result = __syscall_pause ();

    LIBC_CANCEL_RESET (oldtype);

    return result;
  }

and GDB unwinder is confused by the GCC optimized code,

(gdb) disassemble pause
Dump of assembler code for function pause:
   0x0000007fb7f274c4 <+0>:     stp     x29, x30, [sp,#-32]!
   0x0000007fb7f274c8 <+4>:     mov     x29, sp
   0x0000007fb7f274cc <+8>:     adrp    x0, 0x7fb7fd2000
   0x0000007fb7f274d0 <+12>:    ldr     w0, [x0,#364]
   0x0000007fb7f274d4 <+16>:    stp     x19, x20, [sp,#16]
   0x0000007fb7f274d8 <+20>:    cbnz    w0, 0x7fb7f274e8 <pause+36>

   0x0000007fb7f274dc <+24>:    ldp     x19, x20, [sp,#16]
   0x0000007fb7f274e0 <+28>:    ldp     x29, x30, [sp],#32
   0x0000007fb7f274e4 <+32>:    b       0x7fb7f27434    <---- __syscall_pause

   0x0000007fb7f274e8 <+36>:    bl      0x7fb7f5e080

Note that the program stops in __syscall_pause, but its symbol is
stripped in glibc, so GDB doesn't know where the program stops.
__syscall_pause is a tail call in __libc_pause, so it returns to main
instead of __libc_pause.  As a result, the backtrace is like,

 #0  0x0000007fb7ebca88 in raise () from /lib/aarch64-linux-gnu/libc.so.6
 #1  0x0000007fb7ebfefc in abort () from /lib/aarch64-linux-gnu/libc.so.6
 #2  0x0000000000400640 in handler (signo=14) at ../../../binutils-gdb/gdb/testsuite/gdb.base/relativedebug.c:25
 #3  <signal handler called>
 #4  0x0000007fb7f27478 in ?? () from /lib/aarch64-linux-gnu/libc.so.6   <-- [in __syscall_pause]
 #5  0x0000000000400664 in main () at ../../../binutils-gdb/gdb/testsuite/gdb.base/relativedebug.c:32

looks GDB does nothing wrong here.  I looked back at the test case
gdb.base/relativedebug.exp, which was added
https://sourceware.org/ml/gdb-patches/2006-10/msg00305.html
This test was indented to test the problem that "backtraces no longer
display some libc functions" after separate debug info is installed.
IOW, it makes few sense to test against libc which doesn't have debug
info at all, such as my case.

This patch is to tweak the test case to catch the output of
"info shared", if "(*)" is found for libc.so, which means libc doesn't
have debug info, then skip the test.

gdb/testsuite:

2015-04-30  Yao Qi  <yao.qi@linaro.org>

	* gdb.base/relativedebug.exp: Invoke gdb command
	"info sharedlibrary", and if libc.so doesn't have debug info,
	skip the test.
2015-04-30 09:55:06 +01:00
bfd Automatic date update in version.in 2015-04-30 00:00:08 +00:00
binutils S/390: z13 use GNU attribute to indicate vector ABI 2015-04-27 10:32:23 +02:00
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elfcpp Add chdr_size, Chdr, Chdr_write and Chdr_data 2015-04-08 10:29:40 -07:00
etc
gas Fix an internal error in GAS when assembling a bogus piece of source code. 2015-04-29 17:09:05 +01:00
gdb Skip gdb.base/relativedebug.exp if libc doesn't have debug info 2015-04-30 09:55:06 +01:00
gold Updated translations for various binutils components. 2015-04-29 16:26:14 +01:00
gprof Updated translations for various binutils components. 2015-04-29 16:26:14 +01:00
include S/390: z13 use GNU attribute to indicate vector ABI 2015-04-27 10:32:23 +02:00
intl
ld Link the last *normal against libfoozlib.so 2015-04-29 08:43:22 -07:00
libdecnumber Another part of fixing "make TAGS". 2015-01-22 21:07:31 +02:00
libiberty libiberty/setenv.c: Do not declare environ if defined as a macro. 2015-04-22 12:37:52 -07:00
opcodes Updated translations for various binutils components. 2015-04-29 16:26:14 +01:00
readline Fix executable indicator in file name completion on Windows. 2014-12-30 21:14:25 +02:00
sim Fix problems in the sim sources discovered by running the cppcheck static analysis tool. 2015-04-29 16:02:02 +01:00
texinfo
zlib Add missing ChangeLog entry 2015-03-31 13:15:01 -07:00
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compile
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config.rpath
config.sub Update config.guess and config.sub to the latest upstream version 2015-03-30 16:28:14 -04:00
configure Add --with-system-zlib to top level configure 2015-04-01 04:57:28 -07:00
configure.ac Add --with-system-zlib to top level configure 2015-04-01 04:57:28 -07:00
COPYING
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ltgcc.m4
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lt~obsolete.m4
MAINTAINERS
Makefile.def Make all-bfd depend on all-zlib 2015-03-30 10:18:34 -07:00
Makefile.in Make all-bfd depend on all-zlib 2015-03-30 10:18:34 -07:00
Makefile.tpl Update top-level files from GCC trunk 2015-03-16 09:12:37 -07:00
makefile.vms
missing
mkdep
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move-if-change Update `move-if-change' from gnulib 2014-11-16 17:04:02 +01:00
README
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setup.com
src-release.sh Adjust src-release.sh for sim using the gdb create-version.sh. 2015-04-15 04:08:51 +02:00
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
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If you are receiving this as part of a GDB release, see the file gdb/README.
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see libg++/README, etc.  That'll give you info about this
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It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

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then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
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If you have more than one compiler on your system, it is often best to
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also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

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the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
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