From 1afd5965eda86caed3af7f23fd1f8802831360b6 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Fri, 7 Aug 2015 17:23:58 +0100 Subject: [PATCH] Misc switch_back_to_stepped_thread cleanups Several misc cleanups that prepare the tail end of this function, the part that actually re-resumes the stepped thread. The most non-obvious would be the currently_stepping change, I guess. That's because it isn't ever correct to pass step=1 to target_resume on software single-step targets, and currently_stepping works at a conceptual higher level, it returns step=true even on software step targets. It doesn't really matter on hardware step targets, as the breakpoint will be hit immediately, but it's just wrong on software step targets. I tested it against my x86 software single-step branch, and it indeed fixes failed assertions (that catch spurious PTRACE_SINGLESTEP requests) there. gdb/ChangeLog: 2015-08-07 Pedro Alves * infrun.c (switch_back_to_stepped_thread): Use ecs->ptid instead of inferior_ptid. If the stepped thread vanished, return 0 instead of resuming here. Use reset_ecs. Print the prev_pc and the current stop_pc in log message. Clear trap_expected if the thread advanced. Don't pass currently_stepping to do_target_resume. --- gdb/ChangeLog | 9 +++++++++ gdb/infrun.c | 33 ++++++++++++++++++--------------- 2 files changed, 27 insertions(+), 15 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3a6668a0ea..bd9f96905e 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,12 @@ +2015-08-07 Pedro Alves + + * infrun.c (switch_back_to_stepped_thread): Use ecs->ptid instead + of inferior_ptid. If the stepped thread vanished, return 0 + instead of resuming here. Use reset_ecs. Print the prev_pc and + the current stop_pc in log message. Clear trap_expected if the + thread advanced. Don't pass currently_stepping to + do_target_resume. + 2015-08-07 Pedro Alves * gdbthread.h (struct thread_info) : Extend comment. diff --git a/gdb/infrun.c b/gdb/infrun.c index 94075ce1f2..455fc2d960 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -5717,7 +5717,7 @@ switch_back_to_stepped_thread (struct execution_control_state *ecs) { /* Ignore threads of processes we're not resuming. */ if (!sched_multi - && ptid_get_pid (tp->ptid) != ptid_get_pid (inferior_ptid)) + && ptid_get_pid (tp->ptid) != ptid_get_pid (ecs->ptid)) continue; /* When stepping over a breakpoint, we lock all threads @@ -5781,19 +5781,17 @@ switch_back_to_stepped_thread (struct execution_control_state *ecs) "stepped thread, it has vanished\n"); delete_thread (tp->ptid); - keep_going (ecs); - return 1; + return 0; } if (debug_infrun) fprintf_unfiltered (gdb_stdlog, "infrun: switching back to stepped thread\n"); - ecs->event_thread = tp; - ecs->ptid = tp->ptid; - context_switch (ecs->ptid); + reset_ecs (ecs, tp); + switch_to_thread (tp->ptid); - stop_pc = regcache_read_pc (get_thread_regcache (ecs->ptid)); + stop_pc = regcache_read_pc (get_thread_regcache (tp->ptid)); frame = get_current_frame (); gdbarch = get_frame_arch (frame); @@ -5817,23 +5815,28 @@ switch_back_to_stepped_thread (struct execution_control_state *ecs) if (debug_infrun) fprintf_unfiltered (gdb_stdlog, - "infrun: expected thread advanced also\n"); + "infrun: expected thread advanced also " + "(%s -> %s)\n", + paddress (target_gdbarch (), tp->prev_pc), + paddress (target_gdbarch (), stop_pc)); /* Clear the info of the previous step-over, as it's no - longer valid. It's what keep_going would do too, if - we called it. Must do this before trying to insert - the sss breakpoint, otherwise if we were previously - trying to step over this exact address in another - thread, the breakpoint ends up not installed. */ + longer valid (if the thread was trying to step over a + breakpoint, it has already succeeded). It's what + keep_going would do too, if we called it. Do this + before trying to insert the sss breakpoint, otherwise + if we were previously trying to step over this exact + address in another thread, the breakpoint is + skipped. */ clear_step_over_info (); + tp->control.trap_expected = 0; insert_single_step_breakpoint (get_frame_arch (frame), get_frame_address_space (frame), stop_pc); resume_ptid = user_visible_resume_ptid (tp->control.stepping_command); - do_target_resume (resume_ptid, - currently_stepping (tp), GDB_SIGNAL_0); + do_target_resume (resume_ptid, 0, GDB_SIGNAL_0); prepare_to_wait (ecs); } else -- 2.34.1