binutils-gdb/gdb/testsuite/gdb.ada/str_uninit.exp

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# Copyright 2014-2016 Free Software Foundation, Inc.
Internal error trying to print uninitialized string. Trying to print the value of a string whose size is not known at compile-time before it gets assigned a value can lead to the following internal error: (gdb) p my_str $1 = /[...]/utils.c:1089: internal-error: virtual memory exhausted. What happens is that my_str is described as a reference to an array type whose bounds are dynamic. During the read of that variable's value (in default_read_var_value), we end up resolving dynamic types which, for reference types, makes us also resolve the target of that reference type. This means we resolve our variable to a reference to an array whose bounds are undefined, and unfortunately very far appart. So, when we pass that value to ada-valprint, and in particular to da_val_print_ref, we eventually try to allocate too large of a buffer corresponding to the (bogus) size of our array, hence the internal error. This patch fixes the problem by adding a size_check before trying to print the dereferenced value. To perform this check, a function that was previously specific to ada-lang.c (check_size) gets exported, and renamed to something less prone to name collisions (ada_ensure_varsize_limit). gdb/ChangeLog: * ada-lang.h (ada_ensure_varsize_limit): Declare. * ada-lang.c (check_size): Remove advance declaration. (ada_ensure_varsize_limit): Renames check_size. Replace calls to check_size by calls to ada_ensure_varsize_limit throughout. * ada-valprint.c (ada_val_print_ref): Add call to ada_ensure_varsize_limit. Add comment explaining why. gdb/testsuite/ChangeLog: * gdb.ada/str_uninit: New testcase.
2014-12-08 16:37:00 +01:00
#
# 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/>.
load_lib "ada.exp"
standard_ada_testfile parse
if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug ]] != "" } {
return -1
}
clean_restart ${testfile}
set bp_location [gdb_get_line_number "START" ${testdir}/parse.adb]
if ![runto "parse.adb:$bp_location" ] then {
perror "Couldn't run ${testfile}"
return
}
# Print MY_STR. Since the string has not been initialized, including
# its bounds, anything can happen, including an error. The purpose
# of this test is just to verify that we do not get an _internal_
# error.
gdb_test "print my_str" " = .*"
# Just to be certain that the debugger is really still alive,
# try printing something really simple.
gdb_test "print 1235813" " = 1235813"