/* Target-struct-independent code to start (run) and stop an inferior process.
- Copyright 1986, 1987, 1988, 1989, 1991, 1992, 1993, 1994
+ Copyright 1986, 1987, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996
Free Software Foundation, Inc.
This file is part of GDB.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
-Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#include "defs.h"
-#include <string.h>
+#include "gdb_string.h"
#include <ctype.h>
#include "symtab.h"
#include "frame.h"
#define SKIP_TRAMPOLINE_CODE(pc) 0
#endif
+/* Dynamic function trampolines are similar to solib trampolines in that they
+ are between the caller and the callee. The difference is that when you
+ enter a dynamic trampoline, you can't determine the callee's address. Some
+ (usually complex) code needs to run in the dynamic trampoline to figure out
+ the callee's address. This macro is usually called twice. First, when we
+ enter the trampoline (looks like a normal function call at that point). It
+ should return the PC of a point within the trampoline where the callee's
+ address is known. Second, when we hit the breakpoint, this routine returns
+ the callee's address. At that point, things proceed as per a step resume
+ breakpoint. */
+
+#ifndef DYNAMIC_TRAMPOLINE_NEXTPC
+#define DYNAMIC_TRAMPOLINE_NEXTPC(pc) 0
+#endif
+
/* For SVR4 shared libraries, each call goes through a small piece of
trampoline code in the ".plt" section. IN_SOLIB_CALL_TRAMPOLINE evaluates
to nonzero if we are current stopped in one of these. */
static int trap_expected;
+/* Nonzero if we want to give control to the user when we're notified
+ of shared library events by the dynamic linker. */
+static int stop_on_solib_events;
+
#ifdef HP_OS_BUG
/* Nonzero if the next time we try to continue the inferior, it will
step one instruction and generate a spurious trace trap.
else
pid = target_wait (-1, &w);
+#ifdef HAVE_NONSTEPPABLE_WATCHPOINT
+ have_waited:
+#endif
+
flush_cached_frames ();
/* If it's a new process, add it to the thread database */
continue;
}
- stop_signal = w.value.sig;
-
- stop_pc = read_pc_pid (pid);
-
- if (STOPPED_BY_WATCHPOINT (w))
- {
- write_pc (stop_pc - DECR_PC_AFTER_BREAK);
-
- remove_breakpoints ();
- target_resume (pid, 1, TARGET_SIGNAL_0); /* Single step */
-
- if (target_wait_hook)
- target_wait_hook (pid, &w);
- else
- target_wait (pid, &w);
- insert_breakpoints ();
- }
-
switch (w.kind)
{
case TARGET_WAITKIND_LOADED:
(unsigned int)w.value.integer);
else
printf_filtered ("\nProgram exited normally.\n");
+
+ /* Record the exit code in the convenience variable $_exitcode, so
+ that the user can inspect this again later. */
+ set_internalvar (lookup_internalvar ("_exitcode"),
+ value_from_longest (builtin_type_int,
+ (LONGEST) w.value.integer));
gdb_flush (gdb_stdout);
target_mourn_inferior ();
#ifdef NO_SINGLE_STEP
break;
}
+ stop_signal = w.value.sig;
+
+ stop_pc = read_pc_pid (pid);
+
/* See if a thread hit a thread-specific breakpoint that was meant for
another thread. If so, then step that thread past the breakpoint,
and continue it. */
if (!breakpoint_thread_match (stop_pc - DECR_PC_AFTER_BREAK, pid))
{
/* Saw a breakpoint, but it was hit by the wrong thread. Just continue. */
- write_pc (stop_pc - DECR_PC_AFTER_BREAK);
+ write_pc_pid (stop_pc - DECR_PC_AFTER_BREAK, pid);
remove_breakpoints ();
target_resume (pid, 1, TARGET_SIGNAL_0); /* Single step */
else
target_wait (pid, &w);
insert_breakpoints ();
- target_resume (pid, 0, TARGET_SIGNAL_0);
+
+ /* We need to restart all the threads now. */
+ target_resume (-1, 0, TARGET_SIGNAL_0);
continue;
}
}
/* It's a SIGTRAP or a signal we're interested in. Switch threads,
and fall into the rest of wait_for_inferior(). */
+ /* Save infrun state for the old thread. */
+ save_infrun_state (inferior_pid, prev_pc,
+ prev_func_start, prev_func_name,
+ trap_expected, step_resume_breakpoint,
+ through_sigtramp_breakpoint,
+ step_range_start, step_range_end,
+ step_frame_address, handling_longjmp,
+ another_trap);
+
inferior_pid = pid;
+
+ /* Load infrun state for the new thread. */
+ load_infrun_state (inferior_pid, &prev_pc,
+ &prev_func_start, &prev_func_name,
+ &trap_expected, &step_resume_breakpoint,
+ &through_sigtramp_breakpoint,
+ &step_range_start, &step_range_end,
+ &step_frame_address, &handling_longjmp,
+ &another_trap);
printf_filtered ("[Switching to %s]\n", target_pid_to_str (pid));
flush_cached_frames ();
- trap_expected = 0;
- if (step_resume_breakpoint)
- {
- delete_breakpoint (step_resume_breakpoint);
- step_resume_breakpoint = NULL;
- }
-
- /* Not sure whether we need to blow this away too,
- but probably it is like the step-resume
- breakpoint. */
- if (through_sigtramp_breakpoint)
- {
- delete_breakpoint (through_sigtramp_breakpoint);
- through_sigtramp_breakpoint = NULL;
- }
- prev_pc = 0;
- prev_func_name = NULL;
- step_range_start = 0;
- step_range_end = 0;
- step_frame_address = 0;
- handling_longjmp = 0;
- another_trap = 0;
}
#ifdef NO_SINGLE_STEP
continue;
}
+#ifdef HAVE_STEPPABLE_WATCHPOINT
+ /* It may not be necessary to disable the watchpoint to stop over
+ it. For example, the PA can (with some kernel cooperation)
+ single step over a watchpoint without disabling the watchpoint. */
+ if (STOPPED_BY_WATCHPOINT (w))
+ {
+ resume (1, 0);
+ continue;
+ }
+#endif
+
+#ifdef HAVE_NONSTEPPABLE_WATCHPOINT
+ /* It is far more common to need to disable a watchpoint
+ to step the inferior over it. FIXME. What else might
+ a debug register or page protection watchpoint scheme need
+ here? */
+ if (STOPPED_BY_WATCHPOINT (w))
+ {
+/* At this point, we are stopped at an instruction which has attempted to write
+ to a piece of memory under control of a watchpoint. The instruction hasn't
+ actually executed yet. If we were to evaluate the watchpoint expression
+ now, we would get the old value, and therefore no change would seem to have
+ occurred.
+
+ In order to make watchpoints work `right', we really need to complete the
+ memory write, and then evaluate the watchpoint expression. The following
+ code does that by removing the watchpoint (actually, all watchpoints and
+ breakpoints), single-stepping the target, re-inserting watchpoints, and then
+ falling through to let normal single-step processing handle proceed. Since
+ this includes evaluating watchpoints, things will come to a stop in the
+ correct manner. */
+
+ write_pc (stop_pc - DECR_PC_AFTER_BREAK);
+
+ remove_breakpoints ();
+ target_resume (pid, 1, TARGET_SIGNAL_0); /* Single step */
+
+ if (target_wait_hook)
+ target_wait_hook (pid, &w);
+ else
+ target_wait (pid, &w);
+ insert_breakpoints ();
+ /* FIXME-maybe: is this cleaner than setting a flag? Does it
+ handle things like signals arriving and other things happening
+ in combination correctly? */
+ goto have_waited;
+ }
+#endif
+
+#ifdef HAVE_CONTINUABLE_WATCHPOINT
+ /* It may be possible to simply continue after a watchpoint. */
+ STOPPED_BY_WATCHPOINT (w);
+#endif
+
stop_func_start = 0;
stop_func_name = 0;
/* Don't care about return value; stop_func_start and stop_func_name
another_trap = 1;
break;
+#ifdef SOLIB_ADD
+ case BPSTAT_WHAT_CHECK_SHLIBS:
+ {
+ extern int auto_solib_add;
+
+ /* Check for any newly added shared libraries if we're
+ supposed to be adding them automatically. */
+ if (auto_solib_add)
+ {
+ /* Remove breakpoints, SOLIB_ADD might adjust breakpoint
+ addresses via breakpoint_re_set. */
+ if (breakpoints_inserted)
+ remove_breakpoints ();
+ breakpoints_inserted = 0;
+
+ /* Switch terminal for any messages produced by
+ breakpoint_re_set. */
+ target_terminal_ours_for_output ();
+ SOLIB_ADD (NULL, 0, NULL);
+ target_terminal_inferior ();
+ }
+
+ /* If requested, stop when the dynamic linker notifies
+ gdb of events. This allows the user to get control
+ and place breakpoints in initializer routines for
+ dynamically loaded objects (among other things). */
+ if (stop_on_solib_events)
+ {
+ stop_print_frame = 0;
+ goto stop_stepping;
+ }
+ else
+ {
+ /* We want to step over this breakpoint, then keep going. */
+ another_trap = 1;
+ remove_breakpoints_on_following_step = 1;
+ break;
+ }
+ }
+#endif
+
case BPSTAT_WHAT_LAST:
/* Not a real code, but listed here to shut up gcc -Wall. */
/* If stepping through a line, keep going if still within it. */
if (stop_pc >= step_range_start
&& stop_pc < step_range_end
+#if 0
+/* I haven't a clue what might trigger this clause, and it seems wrong anyway,
+ so I've disabled it until someone complains. -Stu 10/24/95 */
+
/* The step range might include the start of the
function, so if we are at the start of the
step range and either the stack or frame pointers
&& !(stop_pc == step_range_start
&& FRAME_FP (get_current_frame ())
&& (read_sp () INNER_THAN step_sp
- || FRAME_FP (get_current_frame ()) != step_frame_address)))
+ || FRAME_FP (get_current_frame ()) != step_frame_address))
+#endif
+)
{
/* We might be doing a BPSTAT_WHAT_SINGLE and getting a signal.
So definately need to check for sigtramp here. */
goto keep_going;
}
-#if 1
+#if 0
+ /* I disabled this test because it was too complicated and slow. The
+ SKIP_PROLOGUE was especially slow, because it caused unnecessary
+ prologue examination on various architectures. The code in the #else
+ clause has been tested on the Sparc, Mips, PA, and Power
+ architectures, so it's pretty likely to be correct. -Stu 10/24/95 */
+
/* See if we left the step range due to a subroutine call that
we should proceed to the end of. */
handling_longjmp stuff is working. */
))
#else
-/* This is experimental code which greatly simplifies the subroutine call
- test. I've actually tested on the Alpha, and it works great. -Stu */
-
- if (in_prologue (stop_pc, NULL)
- || (prev_func_start != 0
- && stop_func_start == 0))
+ /* This test is a much more streamlined, (but hopefully correct)
+ replacement for the code above. It's been tested on the Sparc,
+ Mips, PA, and Power architectures with good results. */
+
+ if (stop_pc == stop_func_start /* Quick test */
+ || in_prologue (stop_pc, stop_func_start)
+ || IN_SOLIB_CALL_TRAMPOLINE (stop_pc, stop_func_name)
+ || stop_func_start == 0)
#endif
+
{
/* It's a subroutine call. */
tmp = SKIP_TRAMPOLINE_CODE (stop_pc);
if (tmp != 0)
stop_func_start = tmp;
+ else
+ {
+ tmp = DYNAMIC_TRAMPOLINE_NEXTPC (stop_pc);
+ if (tmp)
+ {
+ struct symtab_and_line xxx;
+
+ xxx.pc = tmp;
+ xxx.symtab = NULL;
+ xxx.line = 0;
+ step_resume_breakpoint =
+ set_momentary_breakpoint (xxx, NULL, bp_step_resume);
+ insert_breakpoints ();
+ goto keep_going;
+ }
+ }
/* If we have line number information for the function we
are thinking of stepping into, step into it.
target_terminal_ours ();
+ if (stop_bpstat
+ && stop_bpstat->breakpoint_at
+ && stop_bpstat->breakpoint_at->type == bp_shlib_event)
+ printf_filtered ("Stopped due to shared library event\n");
+
/* Look up the hook_stop and run it if it exists. */
if (stop_command->hook)
signal_print[TARGET_SIGNAL_POLL] = 0;
signal_stop[TARGET_SIGNAL_URG] = 0;
signal_print[TARGET_SIGNAL_URG] = 0;
+
+#ifdef SOLIB_ADD
+ add_show_from_set
+ (add_set_cmd ("stop-on-solib-events", class_support, var_zinteger,
+ (char *) &stop_on_solib_events,
+ "Set stopping for shared library events.\n\
+If nonzero, gdb will give control to the user when the dynamic linker\n\
+notifies gdb of shared library events. The most common event of interest\n\
+to the user would be loading/unloading of a new library.\n",
+ &setlist),
+ &showlist);
+#endif
}
projects / deliverable / binutils-gdb.git / blobdiff