gdb/python: allow for catchpoint type breakpoints in python

This commit adds initial support for catchpoints to the python
breakpoint API.

This commit adds a BP_CATCHPOINT constant which corresponds to
GDB's internal bp_catchpoint.  The new constant is documented in the
manual.

The user can't create breakpoints with type BP_CATCHPOINT after this
commit, but breakpoints that already exist, obtained with the
`gdb.breakpoints` function, can now have this type.  Additionally,
when a stop event is reported for hitting a catchpoint, GDB will now
report a BreakpointEvent with the attached breakpoint being of type
BP_CATCHPOINT - previously GDB would report a generic StopEvent in
this situation.

gdb/ChangeLog:

	* NEWS: Mention Python BP_CATCHPOINT feature.
	* python/py-breakpoint.c (pybp_codes): Add bp_catchpoint support.
	(bppy_init): Likewise.
	(gdbpy_breakpoint_created): Likewise.

gdb/doc/ChangeLog:

	* python.texinfo (Breakpoints In Python): Add BP_CATCHPOINT
	description.

gdb/testsuite/ChangeLog:

	* gdb.python/py-breakpoint.c (do_throw): New function.
	(main): Call do_throw.
	* gdb.python/py-breakpoint.exp (test_catchpoints): New proc.

gdb/testsuite/gdb.python/py-breakpoint.c

@@ -39,6 +39,11 @@ int add (int i)
   return i + i;  /* Break at function add.  */
 }
 
+void
+do_throw ()
+{
+  throw 123;
+}
 
 int main (int argc, char *argv[])
 {
@@ -46,6 +51,15 @@ int main (int argc, char *argv[])
   int bar = 42;
   int i;
 
+  try
+    {
+      do_throw ();
+    }
+  catch (...)
+    {
+      /* Nothing.  */
+    }
+
   for (i = 0; i < 10; i++)
     {
       result += multiply (foo);  /* Break at multiply. */

gdb/testsuite/gdb.python/py-breakpoint.exp

@@ -737,11 +737,71 @@ proc_with_prefix test_bkpt_probe {} {
 	"-probe in spec string"
 }
 
+proc_with_prefix test_catchpoints {} {
+    global srcfile testfile
+    global gdb_prompt decimal
+
+    # Start with a fresh gdb.
+    clean_restart ${testfile}
+
+    if ![runto_main] then {
+	fail "cannot run to main."
+	return 0
+    }
+
+    # Try to create a catchpoint, currently this isn't supported via
+    # the python api.
+    gdb_test "python gdb.Breakpoint (\"syscall\", type=gdb.BP_CATCHPOINT)" \
+	[multi_line \
+	     "gdb.error: BP_CATCHPOINT not supported" \
+	     "Error while executing Python code\\."] \
+	"create a catchpoint via the api"
+
+    # Setup a catchpoint.
+    set num "XXX"
+    gdb_test_multiple "catch throw" "" {
+	-re "The feature \'catch throw\' is not supported.*\r\n$gdb_prompt $" {
+	    unsupported "catch syscall isn't supported"
+	    return -1
+	}
+	-re "Catchpoint ($decimal) \\(throw\\)\r\n$gdb_prompt $" {
+	    set num $expect_out(1,string)
+	    pass $gdb_test_name
+	}
+    }
+
+    # Look for the catchpoint in the breakpoint list.
+    gdb_test_multiline "scan breakpoint list for BP_CATCHPOINT" \
+	"python" "" \
+	"def scan_bp_list ():" "" \
+	"  for b in gdb.breakpoints():" "" \
+	"    if b.type == gdb.BP_CATCHPOINT:" "" \
+	"      print(\"breakpoint #%d, type BP_CATCHPOINT\" % b.number)" "" \
+	"end" ""
+    gdb_test "python scan_bp_list ()" \
+	"breakpoint #${num}, type BP_CATCHPOINT" \
+	"scan breakpoint for BP_CATCHPOINT"
+
+    # Arrange to print something when GDB stops, then continue to the
+    # catchpoint and check we get the expected event.
+    gdb_test_multiline "setup stop event handler" \
+	"python" "" \
+	"def stop_handler (event):" "" \
+	"  if (isinstance (event, gdb.BreakpointEvent)" "" \
+	"      and isinstance (event.breakpoint, gdb.Breakpoint)" "" \
+	"      and event.breakpoint.type == gdb.BP_CATCHPOINT):" "" \
+	"    print (\"Stopped at catchpoint event: %d\" % event.breakpoint.number)" "" \
+	"end" "" \
+	"python gdb.events.stop.connect (stop_handler)" ""
+    gdb_test "continue" "Stopped at catchpoint event: ${num}"
+}
+
 test_bkpt_basic
 test_bkpt_deletion
 test_bkpt_cond_and_cmds
 test_bkpt_invisible
 test_hardware_breakpoints
+test_catchpoints
 test_watchpoints
 test_bkpt_internal
 test_bkpt_eval_funcs