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Kevin Buettner e2b9ea4bbb libthread_db initialization changes related to upcoming glibc-2.34
This commit makes some adjustments to accomodate the upcoming
glibc-2.34 release.  Beginning with glibc-2.34, functionality formerly
contained in libpthread has been moved to libc.  For the time being,
libpthread.so still exists in the file system, but it won't show up in
ldd output and therefore won't be able to trigger initialization of
libthread_db related code.  E.g...

Fedora 34 / glibc-2.33.9000:

[kev@f34-2 gdb]$ ldd testsuite/outputs/gdb.threads/tls/tls
	linux-vdso.so.1 (0x00007ffcf94fa000)
	libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007ff0ba9af000)
	libm.so.6 => /lib64/libm.so.6 (0x00007ff0ba8d4000)
	libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007ff0ba8b9000)
	libc.so.6 => /lib64/libc.so.6 (0x00007ff0ba6c6000)
	/lib64/ld-linux-x86-64.so.2 (0x00007ff0babf0000)

Fedora 34 / glibc-2.33:

[kev@f34-1 gdb]$ ldd testsuite/outputs/gdb.threads/tls/tls
	linux-vdso.so.1 (0x00007fff32dc0000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f815f6de000)
	libstdc++.so.6 => /lib64/libstdc++.so.6 (0x00007f815f4bf000)
	libm.so.6 => /lib64/libm.so.6 (0x00007f815f37b000)
	libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f815f360000)
	libc.so.6 => /lib64/libc.so.6 (0x00007f815f191000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f815f721000)

Note that libpthread is missing from the ldd output for the
glibc-2.33.9000 machine.

This means that (unless we happen to think of some entirely different
mechanism), we'll now need to potentially match "libc" in addition to
"libpthread" as libraries which might be thread libraries.  This
accounts for the change made in solib.c.  Note that the new code
attempts to match "/libc." via strstr().  That trailing dot (".")
avoids inadvertently matching libraries such as libcrypt (and
all the other many libraries which begin with "libc").

To avoid attempts to load libthread_db when encountering older
versions of libc, we now attempt to find "pthread_create" (which is a
symbol that we'd expect to be in any pthread library) in the
associated objfile.  This accounts for the changes in
linux-thread-db.c.

I think that other small adjustments will need to be made elsewhere
too.  I've been working through regressions on my glibc-2.33.9000
machine; I've fixed some fairly "obvious" changes in the testsuite
(which are in other commits).  For the rest, it's not yet clear to me
whether the handful of remaining failures represent a problem in glibc
or gdb.  I'm still investigating, however, I'll note that these are
problems that I only see on my glibc-2.33.9000 machine.

gdb/ChangeLog:

	* solib.c (libpthread_name_p): Match "libc" in addition
	to "libpthread".
	* linux-thread-db.c (libpthread_objfile_p): New function.
	(libpthread_name_p): Adjust preexisting callers to use
	libpthread_objfile_p().
2021-06-11 14:52:38 -07:00
bfd PR27952, Disallow ET_DYN DF_1_PIE linker input 2021-06-11 14:06:47 +09:30
binutils readelf info leaks from one object to the next 2021-06-11 14:23:18 +09:30
config
contrib
cpu
elfcpp
etc
gas x86: Always define TC_PARSE_CONS_EXPRESSION 2021-06-11 06:31:59 -07:00
gdb libthread_db initialization changes related to upcoming glibc-2.34 2021-06-11 14:52:38 -07:00
gdbserver
gdbsupport
gnulib gnulib: import select 2021-06-08 00:47:03 -04:00
gold
gprof PR4283, update gprof manual with note about GMON_OUT_PREFIX 2021-06-03 21:26:33 +09:30
include arc: Construct disassembler options dynamically 2021-06-02 15:32:58 +03:00
intl
ld PR27952, Disallow ET_DYN DF_1_PIE linker input 2021-06-11 14:06:47 +09:30
libctf
libdecnumber
libiberty
opcodes PR1202, mcore disassembler: wrong address loopt 2021-06-03 13:05:57 +09:30
readline
sim sim: cleanup obsolete NULL fallback 2021-06-09 19:07:09 -04:00
texinfo
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ChangeLog sim: leverage gnulib 2021-05-29 11:56:43 -04:00
compile
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config.sub
configure sim: leverage gnulib 2021-05-29 11:56:43 -04:00
configure.ac sim: leverage gnulib 2021-05-29 11:56:43 -04:00
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		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

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

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
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,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
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

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.