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On S/390 we see quite often registers marked as "bad register" in the readelf --debug-dump=frames or objdump -Wf output. 00000000 0000000000000014 00000000 CIE Version: 1 Augmentation: "zR" Code alignment factor: 1 Data alignment factor: -8 Return address column: 14 Augmentation data: 1b DW_CFA_def_cfa: r15 ofs 160 DW_CFA_nop DW_CFA_nop DW_CFA_nop ... 00000050 000000000000001c 00000054 FDE cie=00000000 pc=0000000080000e58..0000000080000e84 DW_CFA_advance_loc: 6 to 0000000080000e5e DW_CFA_offset: r14 at cfa-48 DW_CFA_offset: r15 at cfa-40 DW_CFA_advance_loc: 6 to 0000000080000e64 DW_CFA_def_cfa_offset: 320 DW_CFA_advance_loc: 18 to 0000000080000e76 DW_CFA_restore: bad register: r15 <------ DW_CFA_restore: r14 DW_CFA_def_cfa_offset: 160 This is triggered by this check in display_debug_frames (dwarf.c): case DW_CFA_restore: if (opa >= (unsigned int) cie->ncols || opa >= (unsigned int) fc->ncols) reg_prefix = bad_reg; cie->ncols is number of registers referenced in the CIE which is 15 due to r14 being given as return address column. So for the CFA_restore of r15 a "bad register" is being printed while the same rule on r14 is ok. The reason for this check is to prevent wild memory accesses when reading input with corrupted register values while accessing the col_type/col_offset arrays. However in that case r15 is a perfectly valid register. It just happens not to be mentioned in the CIE. Hence restoring the CIE rule for r15 should end up with the default rule which is DW_CFA_undefined. This probably wasn't observed on other platforms because they either do not use CFA_restore (x86-64) or do not issue CFA_restore on registers with a higher number than the return address column. binutils/ChangeLog: 2016-09-29 Andreas Krebbel <krebbel@linux.vnet.ibm.com> * dwarf.c (frame_display_row): Fix formatting of return address register column. (display_debug_frames): Ignore invalid indices into cie->col_type/cie->col_offset arrays and default to DW_CF_undefined instead. |
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bfd | ||
binutils | ||
config | ||
cpu | ||
elfcpp | ||
etc | ||
gas | ||
gdb | ||
gold | ||
gprof | ||
include | ||
intl | ||
ld | ||
libdecnumber | ||
libiberty | ||
opcodes | ||
readline | ||
sim | ||
texinfo | ||
zlib | ||
.cvsignore | ||
.gitattributes | ||
.gitignore | ||
ChangeLog | ||
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 | ||
README | ||
README-maintainer-mode | ||
setup.com | ||
src-release.sh | ||
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.