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Patrick Palka bb9d5f81c3 Fix PR12526: -location watchpoints for bitfield arguments
PR 12526 reports that -location watchpoints against bitfield arguments
trigger false positives when bits around the bitfield, but not the
bitfield itself, are modified.

This happens because -location watchpoints naturally operate at the
byte level, not at the bit level.  When the address of a bitfield
lvalue is taken, information about the bitfield (i.e. its offset and
size) is lost in the process.

This information must first be retained throughout the lifetime of the
-location watchpoint.  This patch achieves this by adding two new
fields to the watchpoint struct: val_bitpos and val_bitsize.  These
fields are set when a watchpoint is first defined in watch_command_1.
They are both equal to zero if the watchpoint is not a -location
watchpoint or if the argument is not a bitfield.

Then these bitfield parameters are used inside update_watchpoint and
watchpoint_check to extract the actual value of the bitfield from the
watchpoint address, with the help of a local helper function
extract_bitfield_from_watchpoint_value.

Finally when creating a HW breakpoint pointing to a bitfield, we
optimize the address and length of the breakpoint.  By skipping over
the bytes that don't cover the bitfield, this step reduces the
frequency at which a read watchpoint for the bitfield is triggered.
It also reduces the number of times a false-positive call to
check_watchpoint is triggered for a write watchpoint.

gdb/
	PR breakpoints/12526
	* breakpoint.h (struct watchpoint): New fields val_bitpos and
	val_bitsize.
	* breakpoint.c (watch_command_1): Use these fields to retain
	bitfield information.
	(extract_bitfield_from_watchpoint_value): New function.
	(watchpoint_check): Use it.
	(update_watchpoint): Use it.  Optimize the address and length of a
	HW watchpoint pointing to a bitfield.
	* value.h (unpack_value_bitfield): New prototype.
	* value.c (unpack_value_bitfield): Make extern.

gdb/testsuite/
	PR breakpoints/12526
	* gdb.base/watch-bitfields.exp: New file.
	* gdb.base/watch-bitfields.c: New file.
2014-09-16 17:40:06 +01:00
bfd Make the linker return an error status if it fails to merge ARM binaries with 2014-09-16 13:08:22 +01:00
binutils Make the linker return an error status if it fails to merge ARM binaries with 2014-09-16 13:08:22 +01:00
config Fix --diable-shared --enable-plugins build breakage 2014-08-19 21:59:56 +09:30
cpu or1k: add missing l.msync, l.psync and l.psync instructions. 2014-07-20 20:26:09 +03:00
elfcpp Add support for MIPS R6. 2014-09-15 12:15:55 +01:00
etc PR external/{16327,16328}: Remove etc/configure.texi and etc/standards.texi. 2014-06-27 11:33:25 +02:00
gas Add -mevexrcig={rne|rd|ru|rz} option to x86 assembler. 2014-09-16 08:45:28 -07:00
gdb Fix PR12526: -location watchpoints for bitfield arguments 2014-09-16 17:40:06 +01:00
gold Add NaCl (NativeClient) specific classes Target_mips_nacl and 2014-09-03 09:44:11 -07:00
gprof Fix --diable-shared --enable-plugins build breakage 2014-08-19 21:59:56 +09:30
include NDS32: Code refactoring of relaxation. 2014-09-16 13:08:00 +08:00
intl
ld Make the linker return an error status if it fails to merge ARM binaries with 2014-09-16 13:08:22 +01:00
libdecnumber PR c/59871 c/ * c-typeck.c (build_compound_expr): Warn even for right-hand operand of a comma expression. (emit_side_effect_warnings): Likewise. libdecnumber/ * decNumberLocal.h (UBFROMUS, UBFROMUI): Remove last argument. testsuite/ * gcc.dg/20020220-2.c: Adjust dg-warning message. * gcc.dg/pr59871.c: New test. 2014-05-08 10:18:28 -06:00
libiberty Delete temporary string within demangler even in failure cases. 2014-06-11 11:41:51 +01:00
opcodes NDS32/opcodes: Add audio ISA extension and modify the disassemble implemnt. 2014-09-16 12:28:11 +08:00
readline * readline.c (bind_arrow_keys_internal): 2013-09-24 14:49:48 +00:00
sim Shadow SIM's debug_printf function 2014-08-28 11:59:09 +01:00
texinfo
.cvsignore
.gitattributes Add a .gitattributes file for use with git-merge-changelog 2014-07-25 18:07:23 -04:00
.gitignore Sync the root .gitignore file with GCC's. 2013-01-11 15:17:35 +00:00
ChangeLog Add mips*-img-elf* target triple. 2014-09-12 14:25:15 +01:00
compile
config-ml.in * config-ml.in: Don't handle arc-*-elf*. 2011-03-22 20:01:13 +00:00
config.guess * config.sub, config.guess: Import from upstream. 2014-05-01 21:49:01 +01:00
config.rpath
config.sub Import config.sub from upstream config repo 2014-07-29 07:04:52 -04:00
configure Add mips*-img-elf* target triple. 2014-09-12 14:25:15 +01:00
configure.ac Add mips*-img-elf* target triple. 2014-09-12 14:25:15 +01:00
COPYING
COPYING.LIB
COPYING.LIBGLOSS 2013-01-07 Jeff Johnston <jjohnstn@redhat.com> 2013-01-07 21:39:26 +00:00
COPYING.NEWLIB 2013-10-01 Jeff Johnston <jjohnstn@redhat.com> 2013-10-01 18:14:04 +00:00
COPYING3
COPYING3.LIB
depcomp
djunpack.bat
install-sh
libtool.m4 * libtool.m4 (_LT_ENABLE_LOCK <ld -m flags>): Remove non-canonical 2013-09-20 09:51:25 +00:00
ltgcc.m4
ltmain.sh PR target/59788 2014-02-06 11:01:57 +01:00
ltoptions.m4
ltsugar.m4
ltversion.m4
lt~obsolete.m4
MAINTAINERS MAINTAINERS: clarify policy with config/ (and other top level files) 2012-05-12 03:10:17 +00:00
Makefile.def PR sanitizer/56781 * Makefile.def: Set bootstrap=true; for host fixincludes. * configure.ac: Don't bootstrap host fixincludes unless --with-build-config=bootstrap-{a,ub}san. * Makefile.in: Regenerated. * configure: Regenerated. 2014-05-08 10:18:30 -06:00
Makefile.in PR sanitizer/56781 * Makefile.def: Set bootstrap=true; for host fixincludes. * configure.ac: Don't bootstrap host fixincludes unless --with-build-config=bootstrap-{a,ub}san. * Makefile.in: Regenerated. * configure: Regenerated. 2014-05-08 10:18:30 -06:00
Makefile.tpl PR bootstrap/58572 * Makefile.tpl (POSTSTAGE1_CXX_EXPORT): Use -isystem instead of -I for libstdc++-v3 includes if $(LEAN). * Makefile.in: Regenerated. 2014-05-08 10:18:29 -06:00
makefile.vms
missing
mkdep
mkinstalldirs
move-if-change
README
README-maintainer-mode
setup.com
src-release.sh src-release.sh: Convert src-release to a shell script 2014-08-27 13:50:06 +01:00
symlink-tree
ylwrap

		   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.