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Tom Tromey 3b3978bca2 Introduce thread-safe way to handle SIGSEGV
The gdb demangler installs a SIGSEGV handler in order to protect gdb
from demangler bugs.  However, this is not thread-safe, as signal
handlers are global to the process.

This patch changes gdb to always install a global SIGSEGV handler, and
then lets threads indicate their interest in handling the signal by
setting a thread-local variable.

This patch then arranges for the demangler code to use this; being
sure to arrange for calls to warning and the like to be done on the
main thread.

One thing I wondered while writing this patch is if there are any
systems that do not have "sigaction".  If gdb could assume this, it
would simplify this code.

gdb/ChangeLog
2019-11-26  Tom Tromey  <tom@tromey.com>

	* event-top.h (thread_local_segv_handler): Declare.
	* event-top.c (thread_local_segv_handler): New global.
	(install_handle_sigsegv, handle_sigsegv): New functions.
	(async_init_signals): Install SIGSEGV handler.
	* cp-support.c (gdb_demangle_jmp_buf): Change type.  Now
	thread-local.
	(report_failed_demangle): New function.
	(gdb_demangle): Make core_dump_allowed atomic.  Remove signal
	handler-setting code, instead use segv_handler.  Run warning code
	on main thread.

Change-Id: Ic832bbb033b64744e4b44f14b41db7e4168ce427
2019-11-26 14:02:57 -07:00
bfd Fix comparison operations in SH code that trigger warning in clang. 2019-11-26 14:06:12 +00:00
binutils Introduce new section flag: SEC_ELF_OCTETS 2019-11-25 14:32:19 +10:30
config
contrib contrib: Update dg-extract-results.* from gcc 2019-10-21 15:26:48 +01:00
cpu cpu: fix comment in bpf.cpu 2019-11-20 10:16:24 +01:00
elfcpp
etc
gas Fix "psb CSYNC" and "bti C". 2019-11-25 18:27:26 +00:00
gdb Introduce thread-safe way to handle SIGSEGV 2019-11-26 14:02:57 -07:00
gnulib Add no-dist to gnulib configure 2019-11-15 13:48:27 -07:00
gold Introduce new .text.sorted.* sections. 2019-11-26 17:20:10 +01:00
gprof Revert previous delta. 2019-11-15 11:52:50 +00:00
include Introduce new section flag: SEC_ELF_OCTETS 2019-11-25 14:32:19 +10:30
intl
ld Introduce new .text.sorted.* sections. 2019-11-26 17:20:10 +01:00
libctf
libdecnumber
libiberty
opcodes Arm: Change CRC from fpu feature to archititectural extension 2019-11-22 13:47:26 +00:00
readline Minor updates to readline configury 2019-11-15 13:46:54 -07:00
sim
texinfo
zlib
.cvsignore
.gitattributes
.gitignore
ar-lib
ChangeLog Add libctf to src-release.sh:GDB_SUPPORT_DIRS 2019-10-17 14:00:51 -04:00
compile
config-ml.in
config.guess
config.rpath
config.sub
configure
configure.ac
COPYING
COPYING3
COPYING3.LIB
COPYING.LIB
COPYING.LIBGLOSS
COPYING.NEWLIB
depcomp
djunpack.bat
install-sh
libtool.m4
lt~obsolete.m4
ltgcc.m4
ltmain.sh
ltoptions.m4
ltsugar.m4
ltversion.m4
MAINTAINERS
Makefile.def
Makefile.in
Makefile.tpl
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
multilib.am
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setup.com
src-release.sh Add libctf to src-release.sh:GDB_SUPPORT_DIRS 2019-10-17 14:00:51 -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.