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a6a20ad7a1
We noticed the following hang trying to run a program where one
of the subroutines we built without debugging info (opaque_routine):
$ gdb my_program
(gdb) break opaque_routine
(gdb) run
[...hangs...]
The problem comes from the fact that, at the breakpoint's address,
we have the following code:
=> 0x0000000000401994 <+4>: pop %rbp
At some point after hitting the breakpoint and stopping, GDB calls
amd64_windows_frame_decode_epilogue, which then gets stuck in the
following infinite loop:
| /* We don't care about the instruction deallocating the frame:
| if it hasn't been executed, the pc is still in the body,
| if it has been executed, the following epilog decoding will work. */
|
| /* First decode:
| - pop reg [41 58-5f] or [58-5f]. */
|
| while (1)
| {
| /* Read opcode. */
| if (target_read_memory (pc, &op, 1) != 0)
| return -1;
|
| if (op >= 0x40 && op <= 0x4f)
| {
| /* REX prefix. */
| rex = op;
|
| /* Read opcode. */
| if (target_read_memory (pc + 1, &op, 1) != 0)
| return -1;
| }
| else
| rex = 0;
|
| if (op >= 0x58 && op <= 0x5f)
| {
| /* pop reg */
| gdb_byte reg = (op & 0x0f) | ((rex & 1) << 3);
|
| cache->prev_reg_addr[amd64_windows_w2gdb_regnum[reg]] = cur_sp;
| cur_sp += 8;
| }
| else
| break;
|
| /* Allow the user to break this loop. This shouldn't happen as the
| number of consecutive pop should be small. */
| QUIT;
| }
Nothing in that loop updates PC, and therefore, because the instruction
we stopped at is a "pop", we keep looping forever doing the same thing
over and over!
This patch fixes the issue by advancing PC to the beginning of
the next instruction if the current one is a "pop reg" instruction.
gdb/ChangeLog:
* amd64-windows-tdep.c (amd64_windows_frame_decode_epilogue):
Increment PC in while loop skipping "pop reg" instructions.
|
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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.