From c1b5a1a6e732a65350af930c499b23018f8663cc Mon Sep 17 00:00:00 2001 From: Joel Brobecker Date: Mon, 8 Dec 2014 10:37:00 -0500 Subject: 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. --- gdb/testsuite/gdb.ada/str_uninit.exp | 40 ++++++++++++++++++++++++++++++ gdb/testsuite/gdb.ada/str_uninit/parse.adb | 22 ++++++++++++++++ gdb/testsuite/gdb.ada/str_uninit/pck.adb | 28 +++++++++++++++++++++ gdb/testsuite/gdb.ada/str_uninit/pck.ads | 24 ++++++++++++++++++ 4 files changed, 114 insertions(+) create mode 100644 gdb/testsuite/gdb.ada/str_uninit.exp create mode 100644 gdb/testsuite/gdb.ada/str_uninit/parse.adb create mode 100644 gdb/testsuite/gdb.ada/str_uninit/pck.adb create mode 100644 gdb/testsuite/gdb.ada/str_uninit/pck.ads (limited to 'gdb/testsuite/gdb.ada') diff --git a/gdb/testsuite/gdb.ada/str_uninit.exp b/gdb/testsuite/gdb.ada/str_uninit.exp new file mode 100644 index 0000000..706d57d --- /dev/null +++ b/gdb/testsuite/gdb.ada/str_uninit.exp @@ -0,0 +1,40 @@ +# Copyright 2014 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 . + +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" diff --git a/gdb/testsuite/gdb.ada/str_uninit/parse.adb b/gdb/testsuite/gdb.ada/str_uninit/parse.adb new file mode 100644 index 0000000..8567377 --- /dev/null +++ b/gdb/testsuite/gdb.ada/str_uninit/parse.adb @@ -0,0 +1,22 @@ +-- Copyright 2014 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 . + +with Pck; use Pck; + +procedure Parse is + My_Str : String := Foos; -- START +begin + Do_Nothing (My_Str'Address); +end Parse; diff --git a/gdb/testsuite/gdb.ada/str_uninit/pck.adb b/gdb/testsuite/gdb.ada/str_uninit/pck.adb new file mode 100644 index 0000000..bfc5305 --- /dev/null +++ b/gdb/testsuite/gdb.ada/str_uninit/pck.adb @@ -0,0 +1,28 @@ +-- Copyright 2011-2014 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 . + +package body Pck is + + procedure Do_Nothing (A : System.Address) is + begin + null; + end Do_Nothing; + + function Foos return String is + begin + return "string"; + end Foos; + +end Pck; diff --git a/gdb/testsuite/gdb.ada/str_uninit/pck.ads b/gdb/testsuite/gdb.ada/str_uninit/pck.ads new file mode 100644 index 0000000..e109375 --- /dev/null +++ b/gdb/testsuite/gdb.ada/str_uninit/pck.ads @@ -0,0 +1,24 @@ +-- Copyright 2011-2014 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 . + +with System; + +package Pck is + + procedure Do_Nothing (A : System.Address); + + function Foos return String; + +end Pck; -- cgit v1.1