7c16b83e05
This patch makes single-step breakpoints "real" breakpoints on the global location list. There are several benefits to this: - It removes the currently limitation that only 2 single-step breakpoints can be inserted. See an example here of a discussion around a case that wants more than 2, possibly unbounded: https://sourceware.org/ml/gdb-patches/2014-03/msg00663.html - makes software single-step work on read-only code regions. The logic to convert a software breakpoint to a hardware breakpoint if the memory map says the breakpoint address is in read only memory is in insert_bp_location. Because software single-step breakpoints bypass all that go and straight to target_insert_breakpoint, we can't software single-step over read only memory. This patch removes that limitation, and adds a test that makes sure that works, by forcing a code region to read-only with "mem LOW HIGH ro" and then stepping through that. - Fixes PR breakpoints/9649 This is an assertion failure in insert_single_step_breakpoint in breakpoint.c, because we may leave stale single-step breakpoints behind on error. The tests for stepping through read-only regions exercise the root cause of the bug, which is that we leave single-step breakpoints behind if we fail to insert any single-step breakpoint. Deleting the single-step breakpoints in resume_cleanups, delete_just_stopped_threads_infrun_breakpoints, and fetch_inferior_event fixes this. Without that, we'd no longer hit the assertion, as that code is deleted, but we'd instead run into errors/warnings trying to insert/remove the stale breakpoints on next resume. - Paves the way to have multiple threads software single-stepping at the same time, leaving update_global_location_list to worry about duplicate locations. - Makes the moribund location machinery aware of software single-step breakpoints, paving the way to enable software single-step on non-stop, instead of forcing serialized displaced stepping for all single steps. - It's generaly cleaner. We no longer have to play games with single-step breakpoints inserted at the same address as regular breakpoints, like we recently had to do for 7.8. See this discussion: https://sourceware.org/ml/gdb-patches/2014-06/msg00052.html. Tested on x86_64 Fedora 20, on top of my 'single-step breakpoints on x86' series. gdb/ 2014-10-15 Pedro Alves <palves@redhat.com> PR breakpoints/9649 * breakpoint.c (single_step_breakpoints, single_step_gdbarch): Delete array globals. (single_step_breakpoints): New global. (breakpoint_xfer_memory): Remove special handling for single-step breakpoints. (update_breakpoints_after_exec): Delete bp_single_step breakpoints. (detach_breakpoints): Remove special handling for single-step breakpoints. (breakpoint_init_inferior): Delete bp_single_step breakpoints. (bpstat_stop_status): Add comment. (bpstat_what, bptype_string, print_one_breakpoint_location) (adjust_breakpoint_address, init_bp_location): Handle bp_single_step. (new_single_step_breakpoint): New function. (set_momentary_breakpoint, bkpt_remove_location): Remove special handling for single-step breakpoints. (insert_single_step_breakpoint, single_step_breakpoints_inserted) (remove_single_step_breakpoints, cancel_single_step_breakpoints): Rewrite. (detach_single_step_breakpoints, find_single_step_breakpoint): Delete functions. (breakpoint_has_location_inserted_here): New function. (single_step_breakpoint_inserted_here_p): Rewrite. * breakpoint.h: Remove FIXME. (enum bptype) <bp_single_step>: New enum value. (insert_single_step_breakpoint): Update comment. * infrun.c (resume_cleanups) (delete_step_thread_step_resume_breakpoint): Remove single-step breakpoints. (fetch_inferior_event): Install a cleanup that removes infrun breakpoints. (switch_back_to_stepped_thread) <expect thread advanced also>: Clear step-over info. gdb/testsuite/ 2014-10-15 Pedro Alves <palves@redhat.com> PR breakpoints/9649 * gdb.base/breakpoint-in-ro-region.c (main): Add more instructions. * gdb.base/breakpoint-in-ro-region.exp (probe_target_hardware_step): New procedure. (top level): Probe hardware stepping and hardware breakpoint support. Test stepping through a read-only region, with both "breakpoint auto-hw" on and off and both "always-inserted" on and off.
37 lines
907 B
C
37 lines
907 B
C
/* This testcase is part of GDB, the GNU debugger.
|
|
|
|
Copyright 2014 Free Software Foundation, Inc.
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>. */
|
|
|
|
volatile int i;
|
|
|
|
int
|
|
main (void)
|
|
{
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
i = 0;
|
|
|
|
return 0;
|
|
}
|