binutils-gdb/gdb/testsuite/lib/prompt.exp
Anders Granlund 717cf30c82 Introduce gdb_interact in testsuite
gdb_interact is a small utility that we have found quite useful to debug
test cases.

Putting gdb_interact in a test suspends it and allows to interact with
gdb to inspect whatever you want. You can then type ">>>" to resume the
test execution. Of course, this is only for gdb devs. It wouldn't make
sense to leave a gdb_interact permanently in a test case.

When starting the interaction with the user, the script prints this
banner:

+------------------------------------------+
| Script interrupted, you can now interact |
| with by gdb. Type >>> to continue.       |
+------------------------------------------+

Notes:
* When gdb is launched, the gdb_spawn_id variable (lib/gdb.exp) is
  assigned -1. Given the name, I would expect it to contain the gdb
  expect spawn id, which is needed for interact. I changed all places
  that set gdb_spawn_id to -1 to set it to the actual gdb spawn id
  instead.

* When entering the "interact" mode, the last (gdb) prompt is already
  eaten by expect, so it doesn't show up on the terminal. Subsequent
  prompts do appear though. We tried to print "(gdb)" just before the
  interact to replace it. However, it could be misleading if you are
  debugging an MI test case, it makes you think that you are typing in a
  CLI prompt, when in reality it's MI. In the end I decided that since
  the feature is for developers who know what they're doing and that one
  is normally consciously using gdb_interact, the script doesn't need
  to babysit the user.

* There are probably some quirks depending on where in the script
  gdb_interact appears (e.g. it could interfere with following
  commands and make them fail), but it works for most cases. Quirks can
  always be fixed later.

The idea and original implementation was contributed by Anders
Granlund, a colleague of mine. Thanks to him.

gdb/testsuite/ChangeLog:

	* gdb.base/statistics.exp: Assign spawn id to gdb_spawn_id.
	* gdb.base/valgrind-db-attach.exp: Same.
	* gdb.base/valgrind-infcall.exp: Same.
	* lib/mi-support.exp (default_mi_gdb_start): Same.
	* lib/prompt.exp (default_prompt_gdb_start): Same.
	* lib/gdb.exp (default_gdb_spawn): Same.
	(gdb_interact): New.
2015-01-22 15:49:08 -05:00

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# Copyright (C) 2011-2015 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/>.
# Specialized subroutines for launching gdb and testing the very first prompt.
#
# start gdb -- start gdb running, prompt procedure
# this procedure differs from the default in that you must pass 'set height 0',
# and 'set width 0', yourself in GDBFLAGS, and it has a gdb_prompt_fail variable,
#
# uses pass if it sees $gdb_prompt, and fail if it sees $gdb_prompt_fail.
#
proc default_prompt_gdb_start { } {
global verbose
global GDB
global INTERNAL_GDBFLAGS GDBFLAGS
global gdb_prompt
global gdb_prompt_fail
global timeout
global gdb_spawn_id
gdb_stop_suppressing_tests
verbose "Spawning $GDB $INTERNAL_GDBFLAGS $GDBFLAGS"
if [info exists gdb_spawn_id] {
return 0
}
if ![is_remote host] {
if { [which $GDB] == 0 } then {
perror "$GDB does not exist."
exit 1
}
}
set res [remote_spawn host "$GDB $INTERNAL_GDBFLAGS $GDBFLAGS [host_info gdb_opts]"]
if { $res < 0 || $res == "" } {
perror "Spawning $GDB failed."
return 1
}
gdb_expect 360 {
-re ".*$gdb_prompt_fail.*$gdb_prompt_fail.*" {
fail "double prompted fail prompt"
}
-re ".*$gdb_prompt.*$gdb_prompt.*" {
fail "double prompted"
}
-re "\[\r\n\]$gdb_prompt_fail $" {
fail "GDB initializing first prompt"
}
-re "\[\r\n\]$gdb_prompt $" {
pass "GDB initializing first prompt"
}
-re "$gdb_prompt $" {
perror "GDB never initialized."
return -1
}
-re "$gdb_prompt_fail $" {
perror "GDB never initialized."
return -1
}
timeout {
perror "(timeout) GDB never initialized after 10 seconds."
remote_close host
return -1
}
}
set gdb_spawn_id $res
return 0
}
#
# Overridable function. You can override this function in your
# baseboard file.
#
proc prompt_gdb_start { } {
default_prompt_gdb_start
}