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libraries. As explained in https://sourceware.org/ml/gdb-patches/2008-08/msg00361.html, after a shared library was unloaded, we can no longer insert or remove breakpoints into/from its (no longer present) code segment. That'll fail with memory errors. However, that concern does not apply to hardware breakpoints. By definition, hardware breakpoints are implemented using a mechanism that is not dependent on being able to modify the target's memory. Usually, by setting up CPU debug registers. IOW, we should be able to set hw breakpoints in an unmapped address. We don't seem to have a test that exercises that, so this patch adds one. I noticed the error supression because of a related issue -- the target_insert_hw_breakpoint/target_remove_hw_breakpoint interfaces don't really distinguish "not supported" from "error" return, and so remote.c returns -1 in both cases. This results in hardware breakpoints set in shared libraries silently ending up pending forever even though the target doesn't actually support hw breakpoints. (gdb) set breakpoint always-inserted on (gdb) set remote Z-packet off (gdb) info breakpoints No breakpoints or watchpoints. (gdb) hbreak shrfunc Hardware assisted breakpoint 3 at 0x7ffff7dfb657: file ../../../src/gdb/testsuite/gdb.base/hbreak-in-shr-unsupported-shr.c, line 21. (gdb) info break Num Type Disp Enb Address What 3 hw breakpoint keep y <PENDING> shrfunc After the patch we get the expected: (gdb) hbreak shrfunc Hardware assisted breakpoint 3 at 0x7ffff7dfb657: file ../../../src/gdb/testsuite/gdb.base/hbreak-in-shr-unsupported-shr.c, line 21. Warning: Cannot insert hardware breakpoint 3. Could not insert hardware breakpoints: You may have requested too many hardware breakpoints/watchpoints. (gdb) info break Num Type Disp Enb Address What 3 hw breakpoint keep y 0x00007ffff7dfb657 in shrfunc at ../../../src/gdb/testsuite/gdb.base/hbreak-in-shr-unsupported-shr.c:21 (HW breakpoints set in the main executable, when the target doesn't support HW breakpoints always resulted in the latter output.) We probably should improve the insert/remove interface to return a different error code for unsupported. But I chose to fix the error supression first, as it's a deeper and wider issue. Tested on x86_64 Fedora 17, native and gdbserver. gdb/ 2014-04-23 Pedro Alves <palves@redhat.com> * breakpoint.c (insert_bp_location, remove_breakpoint_1): If the breakpoint is set in a shared library, only suppress errors for software breakpoints, not hardware breakpoints. gdb/testsuite/ 2014-04-23 Pedro Alves <palves@redhat.com> * gdb.base/hbreak-in-shr-unsupported-shr.c: New file. * gdb.base/hbreak-in-shr-unsupported.c: New file. * gdb.base/hbreak-in-shr-unsupported.exp: New file. * gdb.base/hbreak-unmapped.c: New file. * gdb.base/hbreak-unmapped.exp: New file. * gdb.trace/qtro.exp (gdb_is_target_remote): Move ... * lib/gdb.exp (gdb_is_target_remote): ... here. |
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| include | ||
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| opcodes | ||
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| COPYING3 | ||
| COPYING3.LIB | ||
| ChangeLog | ||
| MAINTAINERS | ||
| Makefile.def | ||
| Makefile.in | ||
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| README | ||
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README
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.