rpms
/
gdb
2
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
gdb/gdb-6.6-bz237572-ppc-atomic...

1161 lines
42 KiB
Diff
Raw Normal View History

- Support for stepping over PPC atomic instruction sequences (BZ 237572). - `set scheduler-locking step' is no longer enforced but it is now default.
2007-06-21 05:22:01 +00:00
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=235186
2007-01-10 Daniel Jacobowitz <dan@codesourcery.com>
* infrun.c (singlestep_pc): New variable.
(resume): Set singlestep_pc.
(context_switch): Add a debugging message. Flush the frame cache.
(handle_inferior_event): Add debugging messages. Handle thread
hops when a software single step has completed. Let context_switch
handle flushing the frame cache.
--- ./gdb/infrun.c 9 Jan 2007 17:58:51 -0000 1.218
+++ ./gdb/infrun.c 10 Jan 2007 20:10:23 -0000 1.219
@@ -469,6 +469,9 @@ static int singlestep_breakpoints_insert
/* The thread we inserted single-step breakpoints for. */
static ptid_t singlestep_ptid;
+/* PC when we started this single-step. */
+static CORE_ADDR singlestep_pc;
+
/* If another thread hit the singlestep breakpoint, we save the original
thread here so that we can resume single-stepping it later. */
static ptid_t saved_singlestep_ptid;
@@ -563,6 +566,7 @@ resume (int step, enum target_signal sig
`wait_for_inferior' */
singlestep_breakpoints_inserted_p = 1;
singlestep_ptid = inferior_ptid;
+ singlestep_pc = read_pc ();
}
/* If there were any forks/vforks/execs that were caught and are
@@ -1126,6 +1130,14 @@ context_switch (struct execution_control
be lost. This may happen as a result of the target module
mishandling thread creation. */
+ if (debug_infrun)
+ {
+ fprintf_unfiltered (gdb_stdlog, "infrun: Switching context from %s ",
+ target_pid_to_str (inferior_ptid));
+ fprintf_unfiltered (gdb_stdlog, "to %s\n",
+ target_pid_to_str (ecs->ptid));
+ }
+
if (in_thread_list (inferior_ptid) && in_thread_list (ecs->ptid))
{ /* Perform infrun state context switch: */
/* Save infrun state for the old thread. */
@@ -1149,6 +1161,7 @@ context_switch (struct execution_control
&ecs->current_line, &ecs->current_symtab);
}
inferior_ptid = ecs->ptid;
+ flush_cached_frames ();
}
static void
@@ -1609,6 +1622,14 @@ handle_inferior_event (struct execution_
}
else if (SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p)
{
+ /* We have not context switched yet, so this should be true
+ no matter which thread hit the singlestep breakpoint. */
+ gdb_assert (ptid_equal (inferior_ptid, singlestep_ptid));
+ if (debug_infrun)
+ fprintf_unfiltered (gdb_stdlog, "infrun: software single step "
+ "trap for %s\n",
+ target_pid_to_str (ecs->ptid));
+
ecs->random_signal = 0;
/* The call to in_thread_list is necessary because PTIDs sometimes
change when we go from single-threaded to multi-threaded. If
@@ -1617,9 +1638,46 @@ handle_inferior_event (struct execution_
if (!ptid_equal (singlestep_ptid, ecs->ptid)
&& in_thread_list (singlestep_ptid))
{
- thread_hop_needed = 1;
- stepping_past_singlestep_breakpoint = 1;
- saved_singlestep_ptid = singlestep_ptid;
+ /* If the PC of the thread we were trying to single-step
+ has changed, discard this event (which we were going
+ to ignore anyway), and pretend we saw that thread
+ trap. This prevents us continuously moving the
+ single-step breakpoint forward, one instruction at a
+ time. If the PC has changed, then the thread we were
+ trying to single-step has trapped or been signalled,
+ but the event has not been reported to GDB yet.
+
+ There might be some cases where this loses signal
+ information, if a signal has arrived at exactly the
+ same time that the PC changed, but this is the best
+ we can do with the information available. Perhaps we
+ should arrange to report all events for all threads
+ when they stop, or to re-poll the remote looking for
+ this particular thread (i.e. temporarily enable
+ schedlock). */
+ if (read_pc_pid (singlestep_ptid) != singlestep_pc)
+ {
+ if (debug_infrun)
+ fprintf_unfiltered (gdb_stdlog, "infrun: unexpected thread,"
+ " but expected thread advanced also\n");
+
+ /* The current context still belongs to
+ singlestep_ptid. Don't swap here, since that's
+ the context we want to use. Just fudge our
+ state and continue. */
+ ecs->ptid = singlestep_ptid;
+ stop_pc = read_pc_pid (ecs->ptid);
+ }
+ else
+ {
+ if (debug_infrun)
+ fprintf_unfiltered (gdb_stdlog,
+ "infrun: unexpected thread\n");
+
+ thread_hop_needed = 1;
+ stepping_past_singlestep_breakpoint = 1;
+ saved_singlestep_ptid = singlestep_ptid;
+ }
}
}
@@ -1702,8 +1760,6 @@ handle_inferior_event (struct execution_
if (deprecated_context_hook)
deprecated_context_hook (pid_to_thread_id (ecs->ptid));
-
- flush_cached_frames ();
}
if (SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p)
2007-04-12 Luis Machado <luisgpm@br.ibm.com>
* gdbarch.sh (software_single_step): Change the return type
from void to int and reformatted some comments to <= 80
columns.
* gdbarch.c, gdbarch.h: Regenerated.
* alpha-tdep.c (alpha_software_single_step): Likewise.
* alpha-tdep.h (alpha_software_single_step): Likewise.
* arm-tdep.c (arm_software_single_step): Likewise.
* cris-tdep.c (cris_software_single_step): Likewise.
* mips-tdep.c (mips_software_single_step): Likewise.
* mips-tdep.h (mips_software_single_step): Likewise.
* rs6000-tdep.c (rs6000_software_single_step): Likewise.
* rs6000-tdep.h (rs6000_software_single_step): Likewise.
* sparc-tdep.c (sparc_software_single_step): Likewise.
* sparc-tdep.h (sparc_software_single_step): Likewise.
[REMOVED] * spu-tdep.c (spu_software_single_step): Likewise.
* infrun.c (resume): Check the return value from SOFTWARE_SINGLE_STEP
and act accordingly.
--- ./gdb/alpha-tdep.c 27 Feb 2007 20:17:18 -0000 1.162
+++ ./gdb/alpha-tdep.c 12 Apr 2007 14:52:19 -0000 1.163
@@ -1518,7 +1518,7 @@ alpha_next_pc (CORE_ADDR pc)
return (pc + ALPHA_INSN_SIZE);
}
-void
+int
alpha_software_single_step (enum target_signal sig, int insert_breakpoints_p)
{
static CORE_ADDR next_pc;
@@ -1536,6 +1536,7 @@ alpha_software_single_step (enum target_
remove_single_step_breakpoints ();
write_pc (next_pc);
}
+ return 1;
}
--- ./gdb/alpha-tdep.h 9 Jan 2007 17:58:49 -0000 1.27
+++ ./gdb/alpha-tdep.h 12 Apr 2007 14:52:19 -0000 1.28
@@ -107,7 +107,7 @@ struct gdbarch_tdep
};
extern unsigned int alpha_read_insn (CORE_ADDR pc);
-extern void alpha_software_single_step (enum target_signal, int);
+extern int alpha_software_single_step (enum target_signal, int);
extern CORE_ADDR alpha_after_prologue (CORE_ADDR pc);
extern void alpha_mdebug_init_abi (struct gdbarch_info, struct gdbarch *);
--- ./gdb/arm-tdep.c 30 Mar 2007 22:50:33 -0000 1.225
+++ ./gdb/arm-tdep.c 12 Apr 2007 14:52:19 -0000 1.226
@@ -1907,7 +1907,7 @@ arm_get_next_pc (CORE_ADDR pc)
single_step() is also called just after the inferior stops. If we
had set up a simulated single-step, we undo our damage. */
-static void
+static int
arm_software_single_step (enum target_signal sig, int insert_bpt)
{
/* NOTE: This may insert the wrong breakpoint instruction when
@@ -1922,6 +1922,8 @@ arm_software_single_step (enum target_si
}
else
remove_single_step_breakpoints ();
+
+ return 1;
}
#include "bfd-in2.h"
--- ./gdb/cris-tdep.c 27 Feb 2007 20:17:18 -0000 1.138
+++ ./gdb/cris-tdep.c 12 Apr 2007 14:52:19 -0000 1.139
@@ -2119,7 +2119,7 @@ find_step_target (inst_env_type *inst_en
digs through the opcodes in order to find all possible targets.
Either one ordinary target or two targets for branches may be found. */
-static void
+static int
cris_software_single_step (enum target_signal ignore, int insert_breakpoints)
{
inst_env_type inst_env;
@@ -2152,6 +2152,8 @@ cris_software_single_step (enum target_s
}
else
remove_single_step_breakpoints ();
+
+ return 1;
}
/* Calculates the prefix value for quick offset addressing mode. */
--- ./gdb/gdbarch.c 28 Feb 2007 17:34:58 -0000 1.338
+++ ./gdb/gdbarch.c 12 Apr 2007 14:52:19 -0000 1.339
@@ -3289,14 +3289,14 @@ gdbarch_software_single_step_p (struct g
return gdbarch->software_single_step != NULL;
}
-void
+int
gdbarch_software_single_step (struct gdbarch *gdbarch, enum target_signal sig, int insert_breakpoints_p)
{
gdb_assert (gdbarch != NULL);
gdb_assert (gdbarch->software_single_step != NULL);
if (gdbarch_debug >= 2)
fprintf_unfiltered (gdb_stdlog, "gdbarch_software_single_step called\n");
- gdbarch->software_single_step (sig, insert_breakpoints_p);
+ return gdbarch->software_single_step (sig, insert_breakpoints_p);
}
void
--- ./gdb/gdbarch.h 8 Feb 2007 21:00:29 -0000 1.294
+++ ./gdb/gdbarch.h 12 Apr 2007 14:52:19 -0000 1.295
@@ -1144,14 +1144,19 @@ extern void set_gdbarch_smash_text_addre
#define SMASH_TEXT_ADDRESS(addr) (gdbarch_smash_text_address (current_gdbarch, addr))
#endif
-/* FIXME/cagney/2001-01-18: This should be split in two. A target method that indicates if
- the target needs software single step. An ISA method to implement it.
+/* FIXME/cagney/2001-01-18: This should be split in two. A target method that
+ indicates if the target needs software single step. An ISA method to
+ implement it.
- FIXME/cagney/2001-01-18: This should be replaced with something that inserts breakpoints
- using the breakpoint system instead of blatting memory directly (as with rs6000).
+ FIXME/cagney/2001-01-18: This should be replaced with something that inserts
+ breakpoints using the breakpoint system instead of blatting memory directly
+ (as with rs6000).
- FIXME/cagney/2001-01-18: The logic is backwards. It should be asking if the target can
- single step. If not, then implement single step using breakpoints. */
+ FIXME/cagney/2001-01-18: The logic is backwards. It should be asking if the
+ target can single step. If not, then implement single step using breakpoints.
+
+ A return value of 1 means that the software_single_step breakpoints
+ were inserted; 0 means they were not. */
#if defined (SOFTWARE_SINGLE_STEP)
/* Legacy for systems yet to multi-arch SOFTWARE_SINGLE_STEP */
@@ -1168,8 +1173,8 @@ extern int gdbarch_software_single_step_
#define SOFTWARE_SINGLE_STEP_P() (gdbarch_software_single_step_p (current_gdbarch))
#endif
-typedef void (gdbarch_software_single_step_ftype) (enum target_signal sig, int insert_breakpoints_p);
-extern void gdbarch_software_single_step (struct gdbarch *gdbarch, enum target_signal sig, int insert_breakpoints_p);
+typedef int (gdbarch_software_single_step_ftype) (enum target_signal sig, int insert_breakpoints_p);
+extern int gdbarch_software_single_step (struct gdbarch *gdbarch, enum target_signal sig, int insert_breakpoints_p);
extern void set_gdbarch_software_single_step (struct gdbarch *gdbarch, gdbarch_software_single_step_ftype *software_single_step);
#if !defined (GDB_TM_FILE) && defined (SOFTWARE_SINGLE_STEP)
#error "Non multi-arch definition of SOFTWARE_SINGLE_STEP"
--- ./gdb/gdbarch.sh 28 Feb 2007 17:35:00 -0000 1.376
+++ ./gdb/gdbarch.sh 12 Apr 2007 14:52:19 -0000 1.377
@@ -614,15 +614,22 @@ f:=:CORE_ADDR:addr_bits_remove:CORE_ADDR
# It is not at all clear why SMASH_TEXT_ADDRESS is not folded into
# ADDR_BITS_REMOVE.
f:=:CORE_ADDR:smash_text_address:CORE_ADDR addr:addr::core_addr_identity::0
-# FIXME/cagney/2001-01-18: This should be split in two. A target method that indicates if
-# the target needs software single step. An ISA method to implement it.
+
+# FIXME/cagney/2001-01-18: This should be split in two. A target method that
+# indicates if the target needs software single step. An ISA method to
+# implement it.
+#
+# FIXME/cagney/2001-01-18: This should be replaced with something that inserts
+# breakpoints using the breakpoint system instead of blatting memory directly
+# (as with rs6000).
#
-# FIXME/cagney/2001-01-18: This should be replaced with something that inserts breakpoints
-# using the breakpoint system instead of blatting memory directly (as with rs6000).
+# FIXME/cagney/2001-01-18: The logic is backwards. It should be asking if the
+# target can single step. If not, then implement single step using breakpoints.
#
-# FIXME/cagney/2001-01-18: The logic is backwards. It should be asking if the target can
-# single step. If not, then implement single step using breakpoints.
-F:=:void:software_single_step:enum target_signal sig, int insert_breakpoints_p:sig, insert_breakpoints_p
+# A return value of 1 means that the software_single_step breakpoints
+# were inserted; 0 means they were not.
+F:=:int:software_single_step:enum target_signal sig, int insert_breakpoints_p:sig, insert_breakpoints_p
+
# Return non-zero if the processor is executing a delay slot and a
# further single-step is needed before the instruction finishes.
M::int:single_step_through_delay:struct frame_info *frame:frame
--- ./gdb/infrun.c 29 Mar 2007 07:35:39 -0000 1.225
+++ ./gdb/infrun.c 12 Apr 2007 14:52:19 -0000 1.226
@@ -548,14 +548,16 @@ resume (int step, enum target_signal sig
if (SOFTWARE_SINGLE_STEP_P () && step)
{
/* Do it the hard way, w/temp breakpoints */
- SOFTWARE_SINGLE_STEP (sig, 1 /*insert-breakpoints */ );
- /* ...and don't ask hardware to do it. */
- step = 0;
- /* and do not pull these breakpoints until after a `wait' in
- `wait_for_inferior' */
- singlestep_breakpoints_inserted_p = 1;
- singlestep_ptid = inferior_ptid;
- singlestep_pc = read_pc ();
+ if (SOFTWARE_SINGLE_STEP (sig, 1 /*insert-breakpoints */ ))
+ {
+ /* ...and don't ask hardware to do it. */
+ step = 0;
+ /* and do not pull these breakpoints until after a `wait' in
+ `wait_for_inferior' */
+ singlestep_breakpoints_inserted_p = 1;
+ singlestep_ptid = inferior_ptid;
+ singlestep_pc = read_pc ();
+ }
}
/* If there were any forks/vforks/execs that were caught and are
@@ -1378,7 +1380,7 @@ handle_inferior_event (struct execution_
(LONGEST) ecs->ws.value.integer));
gdb_flush (gdb_stdout);
target_mourn_inferior ();
- singlestep_breakpoints_inserted_p = 0; /*SOFTWARE_SINGLE_STEP_P() */
+ singlestep_breakpoints_inserted_p = 0; /* SOFTWARE_SINGLE_STEP_P() */
stop_print_frame = 0;
stop_stepping (ecs);
return;
@@ -1398,7 +1400,7 @@ handle_inferior_event (struct execution_
target_mourn_inferior ();
print_stop_reason (SIGNAL_EXITED, stop_signal);
- singlestep_breakpoints_inserted_p = 0; /*SOFTWARE_SINGLE_STEP_P() */
+ singlestep_breakpoints_inserted_p = 0; /* SOFTWARE_SINGLE_STEP_P() */
stop_stepping (ecs);
return;
@@ -1569,7 +1571,7 @@ handle_inferior_event (struct execution_
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, "infrun: stepping_past_singlestep_breakpoint\n");
/* Pull the single step breakpoints out of the target. */
- SOFTWARE_SINGLE_STEP (0, 0);
+ (void) SOFTWARE_SINGLE_STEP (0, 0);
singlestep_breakpoints_inserted_p = 0;
ecs->random_signal = 0;
@@ -1678,7 +1680,7 @@ handle_inferior_event (struct execution_
if (SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p)
{
/* Pull the single step breakpoints out of the target. */
- SOFTWARE_SINGLE_STEP (0, 0);
+ (void) SOFTWARE_SINGLE_STEP (0, 0);
singlestep_breakpoints_inserted_p = 0;
}
@@ -1749,7 +1751,7 @@ handle_inferior_event (struct execution_
if (SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p)
{
/* Pull the single step breakpoints out of the target. */
- SOFTWARE_SINGLE_STEP (0, 0);
+ (void) SOFTWARE_SINGLE_STEP (0, 0);
singlestep_breakpoints_inserted_p = 0;
}
--- ./gdb/mips-tdep.c 30 Mar 2007 22:50:33 -0000 1.407
+++ ./gdb/mips-tdep.c 12 Apr 2007 14:52:19 -0000 1.408
@@ -2204,7 +2204,7 @@ mips_addr_bits_remove (CORE_ADDR addr)
single_step is also called just after the inferior stops. If we had
set up a simulated single-step, we undo our damage. */
-void
+int
mips_software_single_step (enum target_signal sig, int insert_breakpoints_p)
{
CORE_ADDR pc, next_pc;
@@ -2218,6 +2218,8 @@ mips_software_single_step (enum target_s
}
else
remove_single_step_breakpoints ();
+
+ return 1;
}
/* Test whether the PC points to the return instruction at the
--- ./gdb/mips-tdep.h 30 Mar 2007 22:50:33 -0000 1.20
+++ ./gdb/mips-tdep.h 12 Apr 2007 14:52:20 -0000 1.21
@@ -100,7 +100,7 @@ enum
};
/* Single step based on where the current instruction will take us. */
-extern void mips_software_single_step (enum target_signal, int);
+extern int mips_software_single_step (enum target_signal, int);
/* Tell if the program counter value in MEMADDR is in a MIPS16
function. */
--- ./gdb/rs6000-tdep.c 10 Apr 2007 16:02:41 -0000 1.270
+++ ./gdb/rs6000-tdep.c 12 Apr 2007 14:52:20 -0000 1.271
@@ -722,7 +722,7 @@ rs6000_breakpoint_from_pc (CORE_ADDR *bp
/* AIX does not support PT_STEP. Simulate it. */
-void
+int
rs6000_software_single_step (enum target_signal signal,
int insert_breakpoints_p)
{
@@ -761,6 +761,7 @@ rs6000_software_single_step (enum target
errno = 0; /* FIXME, don't ignore errors! */
/* What errors? {read,write}_memory call error(). */
+ return 1;
}
--- ./gdb/rs6000-tdep.h 27 Feb 2007 23:04:28 -0000 1.3
+++ ./gdb/rs6000-tdep.h 12 Apr 2007 14:52:20 -0000 1.4
@@ -21,8 +21,8 @@
#include "defs.h"
-extern void rs6000_software_single_step (enum target_signal signal,
- int insert_breakpoints_p);
+extern int rs6000_software_single_step (enum target_signal signal,
+ int insert_breakpoints_p);
/* Hook in rs6000-tdep.c for determining the TOC address when
calling functions in the inferior. */
--- ./gdb/sparc-tdep.c 11 Apr 2007 07:10:08 -0000 1.179
+++ ./gdb/sparc-tdep.c 12 Apr 2007 14:52:20 -0000 1.180
@@ -1329,7 +1329,7 @@ sparc_step_trap (unsigned long insn)
return 0;
}
-void
+int
sparc_software_single_step (enum target_signal sig, int insert_breakpoints_p)
{
struct gdbarch *arch = current_gdbarch;
@@ -1359,6 +1359,8 @@ sparc_software_single_step (enum target_
}
else
remove_single_step_breakpoints ();
+
+ return 1;
}
static void
--- ./gdb/sparc-tdep.h 9 Jan 2007 17:58:58 -0000 1.12
+++ ./gdb/sparc-tdep.h 12 Apr 2007 14:52:20 -0000 1.13
@@ -167,8 +167,8 @@ extern struct sparc_frame_cache *
-extern void sparc_software_single_step (enum target_signal sig,
- int insert_breakpoints_p);
+extern int sparc_software_single_step (enum target_signal sig,
+ int insert_breakpoints_p);
extern void sparc_supply_rwindow (struct regcache *regcache,
CORE_ADDR sp, int regnum);
2007-04-14 Ulrich Weigand <uweigand@de.ibm.com>
* alpha-tdep.c (alpha_software_single_step): Do not call write_pc
when removing single-step breakpoints.
--- ./gdb/alpha-tdep.c 12 Apr 2007 14:52:19 -0000 1.163
+++ ./gdb/alpha-tdep.c 14 Apr 2007 16:17:39 -0000 1.164
@@ -1521,7 +1521,7 @@ alpha_next_pc (CORE_ADDR pc)
int
alpha_software_single_step (enum target_signal sig, int insert_breakpoints_p)
{
- static CORE_ADDR next_pc;
+ CORE_ADDR next_pc;
CORE_ADDR pc;
if (insert_breakpoints_p)
@@ -1534,7 +1534,6 @@ alpha_software_single_step (enum target_
else
{
remove_single_step_breakpoints ();
- write_pc (next_pc);
}
return 1;
}
2007-04-14 Ulrich Weigand <uweigand@de.ibm.com>
* gdbarch.sh (software_single_step): Remove "insert_breakpoints_p" and
"sig" arguments, add "regcache" argument.
* gdbarch.c, gdbarch.h: Regenerate.
* infrun.c (resume): Update SOFTWARE_SINGLE_STEP call arguments.
(handle_inferior_event): Call remove_single_step_breakpoints directly
instead of calling SOFTWARE_SINGLE_STEP to remove breakpoints.
* alpha-tdep.c (alpha_software_single_step): Update argument list.
Remove handling of !insert_breakpoints_p case.
* arm-tdep.c (arm_software_single_step): Likewise.
* cris-tdep.c (cris_software_single_step): Likewise.
* mips-tdep.c (mips_software_single_step): Likewise.
* rs6000-tdep.c (rs6000_software_single_step): Likewise.
* sparc-tdep.c (sparc_software_single_step): Likewise.
[REMOVED] * spu-tdep.c (spu_software_single_step): Likewise.
* alpha-tdep.h (alpha_software_single_step): Update prototype.
* mips-tdep.h (mips_software_single_step): Likewise.
* rs6000-tdep.h (rs6000_software_single_step): Likewise.
* sparc-tdep.h (sparc_software_single_step): Likewise.
--- ./gdb/alpha-tdep.c 14 Apr 2007 16:17:39 -0000 1.164
+++ ./gdb/alpha-tdep.c 14 Apr 2007 18:10:54 -0000 1.165
@@ -1391,10 +1391,7 @@ fp_register_sign_bit (LONGEST reg)
/* alpha_software_single_step() is called just before we want to resume
the inferior, if we want to single-step it but there is no hardware
or kernel single-step support (NetBSD on Alpha, for example). We find
- the target of the coming instruction and breakpoint it.
-
- single_step is also called just after the inferior stops. If we had
- set up a simulated single-step, we undo our damage. */
+ the target of the coming instruction and breakpoint it. */
static CORE_ADDR
alpha_next_pc (CORE_ADDR pc)
@@ -1519,22 +1516,14 @@ alpha_next_pc (CORE_ADDR pc)
}
int
-alpha_software_single_step (enum target_signal sig, int insert_breakpoints_p)
+alpha_software_single_step (struct regcache *regcache)
{
- CORE_ADDR next_pc;
- CORE_ADDR pc;
+ CORE_ADDR pc, next_pc;
- if (insert_breakpoints_p)
- {
- pc = read_pc ();
- next_pc = alpha_next_pc (pc);
+ pc = read_pc ();
+ next_pc = alpha_next_pc (pc);
- insert_single_step_breakpoint (next_pc);
- }
- else
- {
- remove_single_step_breakpoints ();
- }
+ insert_single_step_breakpoint (next_pc);
return 1;
}
--- ./gdb/alpha-tdep.h 12 Apr 2007 14:52:19 -0000 1.28
+++ ./gdb/alpha-tdep.h 14 Apr 2007 18:10:54 -0000 1.29
@@ -107,7 +107,7 @@ struct gdbarch_tdep
};
extern unsigned int alpha_read_insn (CORE_ADDR pc);
-extern int alpha_software_single_step (enum target_signal, int);
+extern int alpha_software_single_step (struct regcache *regcache);
extern CORE_ADDR alpha_after_prologue (CORE_ADDR pc);
extern void alpha_mdebug_init_abi (struct gdbarch_info, struct gdbarch *);
--- ./gdb/arm-tdep.c 12 Apr 2007 14:52:19 -0000 1.226
+++ ./gdb/arm-tdep.c 14 Apr 2007 18:10:54 -0000 1.227
@@ -1902,26 +1902,17 @@ arm_get_next_pc (CORE_ADDR pc)
/* single_step() is called just before we want to resume the inferior,
if we want to single-step it but there is no hardware or kernel
single-step support. We find the target of the coming instruction
- and breakpoint it.
-
- single_step() is also called just after the inferior stops. If we
- had set up a simulated single-step, we undo our damage. */
+ and breakpoint it. */
static int
-arm_software_single_step (enum target_signal sig, int insert_bpt)
+arm_software_single_step (struct regcache *regcache)
{
/* NOTE: This may insert the wrong breakpoint instruction when
single-stepping over a mode-changing instruction, if the
CPSR heuristics are used. */
- if (insert_bpt)
- {
- CORE_ADDR next_pc = arm_get_next_pc (read_register (ARM_PC_REGNUM));
-
- insert_single_step_breakpoint (next_pc);
- }
- else
- remove_single_step_breakpoints ();
+ CORE_ADDR next_pc = arm_get_next_pc (read_register (ARM_PC_REGNUM));
+ insert_single_step_breakpoint (next_pc);
return 1;
}
--- ./gdb/cris-tdep.c 12 Apr 2007 14:52:19 -0000 1.139
+++ ./gdb/cris-tdep.c 14 Apr 2007 18:10:54 -0000 1.140
@@ -2120,38 +2120,33 @@ find_step_target (inst_env_type *inst_en
Either one ordinary target or two targets for branches may be found. */
static int
-cris_software_single_step (enum target_signal ignore, int insert_breakpoints)
+cris_software_single_step (struct regcache *regcache)
{
inst_env_type inst_env;
- if (insert_breakpoints)
- {
- /* Analyse the present instruction environment and insert
- breakpoints. */
- int status = find_step_target (&inst_env);
- if (status == -1)
- {
- /* Could not find a target. Things are likely to go downhill
- from here. */
- warning (_("CRIS software single step could not find a step target."));
- }
- else
- {
- /* Insert at most two breakpoints. One for the next PC content
- and possibly another one for a branch, jump, etc. */
- CORE_ADDR next_pc = (CORE_ADDR) inst_env.reg[PC_REGNUM];
- insert_single_step_breakpoint (next_pc);
- if (inst_env.branch_found
- && (CORE_ADDR) inst_env.branch_break_address != next_pc)
- {
- CORE_ADDR branch_target_address
- = (CORE_ADDR) inst_env.branch_break_address;
- insert_single_step_breakpoint (branch_target_address);
- }
- }
+ /* Analyse the present instruction environment and insert
+ breakpoints. */
+ int status = find_step_target (&inst_env);
+ if (status == -1)
+ {
+ /* Could not find a target. Things are likely to go downhill
+ from here. */
+ warning (_("CRIS software single step could not find a step target."));
}
else
- remove_single_step_breakpoints ();
+ {
+ /* Insert at most two breakpoints. One for the next PC content
+ and possibly another one for a branch, jump, etc. */
+ CORE_ADDR next_pc = (CORE_ADDR) inst_env.reg[PC_REGNUM];
+ insert_single_step_breakpoint (next_pc);
+ if (inst_env.branch_found
+ && (CORE_ADDR) inst_env.branch_break_address != next_pc)
+ {
+ CORE_ADDR branch_target_address
+ = (CORE_ADDR) inst_env.branch_break_address;
+ insert_single_step_breakpoint (branch_target_address);
+ }
+ }
return 1;
}
--- ./gdb/gdbarch.c 12 Apr 2007 14:52:19 -0000 1.339
+++ ./gdb/gdbarch.c 14 Apr 2007 18:10:54 -0000 1.340
@@ -1522,8 +1522,8 @@ gdbarch_dump (struct gdbarch *current_gd
#ifdef SOFTWARE_SINGLE_STEP
fprintf_unfiltered (file,
"gdbarch_dump: %s # %s\n",
- "SOFTWARE_SINGLE_STEP(sig, insert_breakpoints_p)",
- XSTRING (SOFTWARE_SINGLE_STEP (sig, insert_breakpoints_p)));
+ "SOFTWARE_SINGLE_STEP(regcache)",
+ XSTRING (SOFTWARE_SINGLE_STEP (regcache)));
#endif
fprintf_unfiltered (file,
"gdbarch_dump: software_single_step = <0x%lx>\n",
@@ -3290,13 +3290,13 @@ gdbarch_software_single_step_p (struct g
}
int
-gdbarch_software_single_step (struct gdbarch *gdbarch, enum target_signal sig, int insert_breakpoints_p)
+gdbarch_software_single_step (struct gdbarch *gdbarch, struct regcache *regcache)
{
gdb_assert (gdbarch != NULL);
gdb_assert (gdbarch->software_single_step != NULL);
if (gdbarch_debug >= 2)
fprintf_unfiltered (gdb_stdlog, "gdbarch_software_single_step called\n");
- return gdbarch->software_single_step (sig, insert_breakpoints_p);
+ return gdbarch->software_single_step (regcache);
}
void
--- ./gdb/gdbarch.h 12 Apr 2007 14:52:19 -0000 1.295
+++ ./gdb/gdbarch.h 14 Apr 2007 18:10:54 -0000 1.296
@@ -1173,14 +1173,14 @@ extern int gdbarch_software_single_step_
#define SOFTWARE_SINGLE_STEP_P() (gdbarch_software_single_step_p (current_gdbarch))
#endif
-typedef int (gdbarch_software_single_step_ftype) (enum target_signal sig, int insert_breakpoints_p);
-extern int gdbarch_software_single_step (struct gdbarch *gdbarch, enum target_signal sig, int insert_breakpoints_p);
+typedef int (gdbarch_software_single_step_ftype) (struct regcache *regcache);
+extern int gdbarch_software_single_step (struct gdbarch *gdbarch, struct regcache *regcache);
extern void set_gdbarch_software_single_step (struct gdbarch *gdbarch, gdbarch_software_single_step_ftype *software_single_step);
#if !defined (GDB_TM_FILE) && defined (SOFTWARE_SINGLE_STEP)
#error "Non multi-arch definition of SOFTWARE_SINGLE_STEP"
#endif
#if !defined (SOFTWARE_SINGLE_STEP)
-#define SOFTWARE_SINGLE_STEP(sig, insert_breakpoints_p) (gdbarch_software_single_step (current_gdbarch, sig, insert_breakpoints_p))
+#define SOFTWARE_SINGLE_STEP(regcache) (gdbarch_software_single_step (current_gdbarch, regcache))
#endif
/* Return non-zero if the processor is executing a delay slot and a
--- ./gdb/gdbarch.sh 12 Apr 2007 14:52:19 -0000 1.377
+++ ./gdb/gdbarch.sh 14 Apr 2007 18:10:54 -0000 1.378
@@ -628,7 +628,7 @@ f:=:CORE_ADDR:smash_text_address:CORE_AD
#
# A return value of 1 means that the software_single_step breakpoints
# were inserted; 0 means they were not.
-F:=:int:software_single_step:enum target_signal sig, int insert_breakpoints_p:sig, insert_breakpoints_p
+F:=:int:software_single_step:struct regcache *regcache:regcache
# Return non-zero if the processor is executing a delay slot and a
# further single-step is needed before the instruction finishes.
--- ./gdb/infrun.c 13 Apr 2007 13:29:42 -0000 1.227
+++ ./gdb/infrun.c 14 Apr 2007 18:10:54 -0000 1.228
@@ -548,7 +548,7 @@ resume (int step, enum target_signal sig
if (SOFTWARE_SINGLE_STEP_P () && step)
{
/* Do it the hard way, w/temp breakpoints */
- if (SOFTWARE_SINGLE_STEP (sig, 1 /*insert-breakpoints */ ))
+ if (SOFTWARE_SINGLE_STEP (current_regcache))
{
/* ...and don't ask hardware to do it. */
step = 0;
@@ -1571,7 +1571,7 @@ handle_inferior_event (struct execution_
if (debug_infrun)
fprintf_unfiltered (gdb_stdlog, "infrun: stepping_past_singlestep_breakpoint\n");
/* Pull the single step breakpoints out of the target. */
- (void) SOFTWARE_SINGLE_STEP (0, 0);
+ remove_single_step_breakpoints ();
singlestep_breakpoints_inserted_p = 0;
ecs->random_signal = 0;
@@ -1680,7 +1680,7 @@ handle_inferior_event (struct execution_
if (SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p)
{
/* Pull the single step breakpoints out of the target. */
- (void) SOFTWARE_SINGLE_STEP (0, 0);
+ remove_single_step_breakpoints ();
singlestep_breakpoints_inserted_p = 0;
}
@@ -1751,7 +1751,7 @@ handle_inferior_event (struct execution_
if (SOFTWARE_SINGLE_STEP_P () && singlestep_breakpoints_inserted_p)
{
/* Pull the single step breakpoints out of the target. */
- (void) SOFTWARE_SINGLE_STEP (0, 0);
+ remove_single_step_breakpoints ();
singlestep_breakpoints_inserted_p = 0;
}
--- ./gdb/mips-tdep.c 12 Apr 2007 14:52:19 -0000 1.408
+++ ./gdb/mips-tdep.c 14 Apr 2007 18:10:54 -0000 1.409
@@ -2199,26 +2199,17 @@ mips_addr_bits_remove (CORE_ADDR addr)
/* mips_software_single_step() is called just before we want to resume
the inferior, if we want to single-step it but there is no hardware
or kernel single-step support (MIPS on GNU/Linux for example). We find
- the target of the coming instruction and breakpoint it.
-
- single_step is also called just after the inferior stops. If we had
- set up a simulated single-step, we undo our damage. */
+ the target of the coming instruction and breakpoint it. */
int
-mips_software_single_step (enum target_signal sig, int insert_breakpoints_p)
+mips_software_single_step (struct regcache *regcache)
{
CORE_ADDR pc, next_pc;
- if (insert_breakpoints_p)
- {
- pc = read_register (mips_regnum (current_gdbarch)->pc);
- next_pc = mips_next_pc (pc);
-
- insert_single_step_breakpoint (next_pc);
- }
- else
- remove_single_step_breakpoints ();
+ pc = read_register (mips_regnum (current_gdbarch)->pc);
+ next_pc = mips_next_pc (pc);
+ insert_single_step_breakpoint (next_pc);
return 1;
}
--- ./gdb/mips-tdep.h 12 Apr 2007 14:52:20 -0000 1.21
+++ ./gdb/mips-tdep.h 14 Apr 2007 18:10:54 -0000 1.22
@@ -100,7 +100,7 @@ enum
};
/* Single step based on where the current instruction will take us. */
-extern int mips_software_single_step (enum target_signal, int);
+extern int mips_software_single_step (struct regcache *regcache);
/* Tell if the program counter value in MEMADDR is in a MIPS16
function. */
--- ./gdb/rs6000-tdep.c 12 Apr 2007 14:52:20 -0000 1.271
+++ ./gdb/rs6000-tdep.c 14 Apr 2007 18:10:54 -0000 1.272
@@ -723,8 +723,7 @@ rs6000_breakpoint_from_pc (CORE_ADDR *bp
/* AIX does not support PT_STEP. Simulate it. */
int
-rs6000_software_single_step (enum target_signal signal,
- int insert_breakpoints_p)
+rs6000_software_single_step (struct regcache *regcache)
{
CORE_ADDR dummy;
int breakp_sz;
@@ -734,30 +733,25 @@ rs6000_software_single_step (enum target
CORE_ADDR breaks[2];
int opcode;
- if (insert_breakpoints_p)
- {
- loc = read_pc ();
+ loc = read_pc ();
- insn = read_memory_integer (loc, 4);
+ insn = read_memory_integer (loc, 4);
- breaks[0] = loc + breakp_sz;
- opcode = insn >> 26;
- breaks[1] = branch_dest (opcode, insn, loc, breaks[0]);
+ breaks[0] = loc + breakp_sz;
+ opcode = insn >> 26;
+ breaks[1] = branch_dest (opcode, insn, loc, breaks[0]);
- /* Don't put two breakpoints on the same address. */
- if (breaks[1] == breaks[0])
- breaks[1] = -1;
+ /* Don't put two breakpoints on the same address. */
+ if (breaks[1] == breaks[0])
+ breaks[1] = -1;
- for (ii = 0; ii < 2; ++ii)
- {
- /* ignore invalid breakpoint. */
- if (breaks[ii] == -1)
- continue;
- insert_single_step_breakpoint (breaks[ii]);
- }
+ for (ii = 0; ii < 2; ++ii)
+ {
+ /* ignore invalid breakpoint. */
+ if (breaks[ii] == -1)
+ continue;
+ insert_single_step_breakpoint (breaks[ii]);
}
- else
- remove_single_step_breakpoints ();
errno = 0; /* FIXME, don't ignore errors! */
/* What errors? {read,write}_memory call error(). */
--- ./gdb/rs6000-tdep.h 12 Apr 2007 14:52:20 -0000 1.4
+++ ./gdb/rs6000-tdep.h 14 Apr 2007 18:10:54 -0000 1.5
@@ -21,8 +21,7 @@
#include "defs.h"
-extern int rs6000_software_single_step (enum target_signal signal,
- int insert_breakpoints_p);
+extern int rs6000_software_single_step (struct regcache *regcache);
/* Hook in rs6000-tdep.c for determining the TOC address when
calling functions in the inferior. */
--- ./gdb/sparc-tdep.c 12 Apr 2007 14:52:20 -0000 1.180
+++ ./gdb/sparc-tdep.c 14 Apr 2007 18:10:54 -0000 1.181
@@ -1330,35 +1330,30 @@ sparc_step_trap (unsigned long insn)
}
int
-sparc_software_single_step (enum target_signal sig, int insert_breakpoints_p)
+sparc_software_single_step (struct regcache *regcache)
{
struct gdbarch *arch = current_gdbarch;
struct gdbarch_tdep *tdep = gdbarch_tdep (arch);
CORE_ADDR npc, nnpc;
- if (insert_breakpoints_p)
- {
- CORE_ADDR pc, orig_npc;
+ CORE_ADDR pc, orig_npc;
- pc = sparc_address_from_register (tdep->pc_regnum);
- orig_npc = npc = sparc_address_from_register (tdep->npc_regnum);
+ pc = sparc_address_from_register (tdep->pc_regnum);
+ orig_npc = npc = sparc_address_from_register (tdep->npc_regnum);
- /* Analyze the instruction at PC. */
- nnpc = sparc_analyze_control_transfer (arch, pc, &npc);
- if (npc != 0)
- insert_single_step_breakpoint (npc);
-
- if (nnpc != 0)
- insert_single_step_breakpoint (nnpc);
-
- /* Assert that we have set at least one breakpoint, and that
- they're not set at the same spot - unless we're going
- from here straight to NULL, i.e. a call or jump to 0. */
- gdb_assert (npc != 0 || nnpc != 0 || orig_npc == 0);
- gdb_assert (nnpc != npc || orig_npc == 0);
- }
- else
- remove_single_step_breakpoints ();
+ /* Analyze the instruction at PC. */
+ nnpc = sparc_analyze_control_transfer (arch, pc, &npc);
+ if (npc != 0)
+ insert_single_step_breakpoint (npc);
+
+ if (nnpc != 0)
+ insert_single_step_breakpoint (nnpc);
+
+ /* Assert that we have set at least one breakpoint, and that
+ they're not set at the same spot - unless we're going
+ from here straight to NULL, i.e. a call or jump to 0. */
+ gdb_assert (npc != 0 || nnpc != 0 || orig_npc == 0);
+ gdb_assert (nnpc != npc || orig_npc == 0);
return 1;
}
--- ./gdb/sparc-tdep.h 12 Apr 2007 14:52:20 -0000 1.13
+++ ./gdb/sparc-tdep.h 14 Apr 2007 18:10:54 -0000 1.14
@@ -167,8 +167,7 @@ extern struct sparc_frame_cache *
-extern int sparc_software_single_step (enum target_signal sig,
- int insert_breakpoints_p);
+extern int sparc_software_single_step (struct regcache *regcache);
extern void sparc_supply_rwindow (struct regcache *regcache,
CORE_ADDR sp, int regnum);
2007-05-11 Ulrich Weigand <uweigand@de.ibm.com>
* breakpoint.c (single_step_breakpoint_inserted_here_p): New function.
(breakpoint_inserted_here_p): Call it.
(software_breakpoint_inserted_here_p): Likewise.
--- ./gdb/breakpoint.c 3 May 2007 17:42:25 -0000 1.247
+++ ./gdb/breakpoint.c 11 May 2007 12:44:34 -0000 1.248
@@ -202,6 +202,8 @@ static void tcatch_command (char *arg, i
static void ep_skip_leading_whitespace (char **s);
+static int single_step_breakpoint_inserted_here_p (CORE_ADDR pc);
+
/* Prototypes for exported functions. */
/* If FALSE, gdb will not use hardware support for watchpoints, even
@@ -1841,6 +1843,10 @@ breakpoint_inserted_here_p (CORE_ADDR pc
}
}
+ /* Also check for software single-step breakpoints. */
+ if (single_step_breakpoint_inserted_here_p (pc))
+ return 1;
+
return 0;
}
@@ -1872,6 +1878,10 @@ software_breakpoint_inserted_here_p (COR
}
}
+ /* Also check for software single-step breakpoints. */
+ if (single_step_breakpoint_inserted_here_p (pc))
+ return 1;
+
return 0;
}
@@ -7951,6 +7961,23 @@ remove_single_step_breakpoints (void)
}
}
+/* Check whether a software single-step breakpoint is inserted at PC. */
+
+static int
+single_step_breakpoint_inserted_here_p (CORE_ADDR pc)
+{
+ int i;
+
+ for (i = 0; i < 2; i++)
+ {
+ struct bp_target_info *bp_tgt = single_step_breakpoints[i];
+ if (bp_tgt && bp_tgt->placed_address == pc)
+ return 1;
+ }
+
+ return 0;
+}
+
/* This help string is used for the break, hbreak, tbreak and thbreak commands.
It is defined as a macro to prevent duplication.
2007-05-08 Paul Gilliam <pgilliam@us.ibm.com>
Luis Machado <luisgpm@br.ibm.com>
* rs6000-tdep.c: (LWARX_MASK, LWARX_INSTRUCTION, LDARX_INSTRUCTION,
STWCX_MASK, STWCX_INSTRUCTION, STDCX_INSTRUCTION, BC_MASK,
BC_INSTRUCTION): Define.
(deal_with_atomic_sequence): New function.
(rs6000_software_single_step): Call deal_with_atomic_sequence.
(rs6000_gdbarch_init): Install deal_with_atomic_sequence as
gdbarch_software_single_step routine.
--- ./gdb/rs6000-tdep.c 7 May 2007 01:25:07 -0000 1.274
+++ ./gdb/rs6000-tdep.c 8 May 2007 12:49:12 -0000 1.275
@@ -707,7 +707,95 @@ rs6000_breakpoint_from_pc (CORE_ADDR *bp
}
-/* AIX does not support PT_STEP. Simulate it. */
+/* Instruction masks used during single-stepping of atomic sequences. */
+#define LWARX_MASK 0xfc0007fe
+#define LWARX_INSTRUCTION 0x7c000028
+#define LDARX_INSTRUCTION 0x7c0000A8
+#define STWCX_MASK 0xfc0007ff
+#define STWCX_INSTRUCTION 0x7c00012d
+#define STDCX_INSTRUCTION 0x7c0001ad
+#define BC_MASK 0xfc000000
+#define BC_INSTRUCTION 0x40000000
+
+/* Checks for an atomic sequence of instructions beginning with a LWARX/LDARX
+ instruction and ending with a STWCX/STDCX instruction. If such a sequence
+ is found, attempt to step through it. A breakpoint is placed at the end of
+ the sequence. */
+
+static int
+deal_with_atomic_sequence (struct regcache *regcache)
+{
+ CORE_ADDR pc = read_pc ();
+ CORE_ADDR breaks[2] = {-1, -1};
+ CORE_ADDR loc = pc;
+ CORE_ADDR branch_bp; /* Breakpoint at branch instruction's destination. */
+ int insn = read_memory_integer (loc, PPC_INSN_SIZE);
+ int insn_count;
+ int index;
+ int last_breakpoint = 0; /* Defaults to 0 (no breakpoints placed). */
+ const int atomic_sequence_length = 16; /* Instruction sequence length. */
+ const int opcode = BC_INSTRUCTION; /* Branch instruction's OPcode. */
+ int bc_insn_count = 0; /* Conditional branch instruction count. */
+
+ /* Assume all atomic sequences start with a lwarx/ldarx instruction. */
+ if ((insn & LWARX_MASK) != LWARX_INSTRUCTION
+ && (insn & LWARX_MASK) != LDARX_INSTRUCTION)
+ return 0;
+
+ /* Assume that no atomic sequence is longer than "atomic_sequence_length"
+ instructions. */
+ for (insn_count = 0; insn_count < atomic_sequence_length; ++insn_count)
+ {
+ loc += PPC_INSN_SIZE;
+ insn = read_memory_integer (loc, PPC_INSN_SIZE);
+
+ /* Assume that there is at most one conditional branch in the atomic
+ sequence. If a conditional branch is found, put a breakpoint in
+ its destination address. */
+ if ((insn & BC_MASK) == BC_INSTRUCTION)
+ {
+ if (bc_insn_count >= 1)
+ return 0; /* More than one conditional branch found, fallback
+ to the standard single-step code. */
+
+ branch_bp = branch_dest (opcode, insn, pc, breaks[0]);
+
+ if (branch_bp != -1)
+ {
+ breaks[1] = branch_bp;
+ bc_insn_count++;
+ last_breakpoint++;
+ }
+ }
+
+ if ((insn & STWCX_MASK) == STWCX_INSTRUCTION
+ || (insn & STWCX_MASK) == STDCX_INSTRUCTION)
+ break;
+ }
+
+ /* Assume that the atomic sequence ends with a stwcx/stdcx instruction. */
+ if ((insn & STWCX_MASK) != STWCX_INSTRUCTION
+ && (insn & STWCX_MASK) != STDCX_INSTRUCTION)
+ return 0;
+
+ loc += PPC_INSN_SIZE;
+ insn = read_memory_integer (loc, PPC_INSN_SIZE);
+
+ /* Insert a breakpoint right after the end of the atomic sequence. */
+ breaks[0] = loc;
+
+ /* Check for duplicated breakpoints. */
+ if (last_breakpoint && (breaks[1] == breaks[0]))
+ last_breakpoint = 0;
+
+ /* Effectively inserts the breakpoints. */
+ for (index = 0; index <= last_breakpoint; index++)
+ insert_single_step_breakpoint (breaks[index]);
+
+ return 1;
+}
+
+/* AIX does not support PT_STEP. Simulate it. */
int
rs6000_software_single_step (struct regcache *regcache)
@@ -724,6 +812,9 @@ rs6000_software_single_step (struct regc
insn = read_memory_integer (loc, 4);
+ if (deal_with_atomic_sequence (regcache))
+ return 1;
+
breaks[0] = loc + breakp_sz;
opcode = insn >> 26;
breaks[1] = branch_dest (opcode, insn, loc, breaks[0]);
@@ -3448,6 +3539,9 @@ rs6000_gdbarch_init (struct gdbarch_info
set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
set_gdbarch_breakpoint_from_pc (gdbarch, rs6000_breakpoint_from_pc);
+ /* Handles single stepping of atomic sequences. */
+ set_gdbarch_software_single_step (gdbarch, deal_with_atomic_sequence);
+
/* Handle the 64-bit SVR4 minimal-symbol convention of using "FN"
for the descriptor and ".FN" for the entry-point -- a user
specifying "break FN" will unexpectedly end up with a breakpoint