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[pushed/Ada] Internal error trying to print uninitialized string.
- From: Joel Brobecker <brobecker at adacore dot com>
- To: gdb-patches at sourceware dot org
- Date: Sat, 13 Dec 2014 11:01:44 -0500
- Subject: [pushed/Ada] Internal error trying to print uninitialized string.
- Authentication-results: sourceware.org; auth=none
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.
Tested on x86_64-linux, and pushed.
---
gdb/ChangeLog | 10 ++++++++
gdb/ada-lang.c | 16 ++++++------
gdb/ada-lang.h | 2 ++
gdb/ada-valprint.c | 6 +++++
gdb/testsuite/ChangeLog | 4 +++
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 ++++++++++++++++++
9 files changed, 143 insertions(+), 9 deletions(-)
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
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c12de3a..079be77 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,15 @@
2014-12-13 Joel Brobecker <brobecker@adacore.com>
+ * 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.
+
+2014-12-13 Joel Brobecker <brobecker@adacore.com>
+
* utils.c (make_hex_string): Replace use of sprintf by use of
xsnprintf.
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 69b43f6..a45e770 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -232,8 +232,6 @@ static int ada_is_direct_array_type (struct type *);
static void ada_language_arch_info (struct gdbarch *,
struct language_arch_info *);
-static void check_size (const struct type *);
-
static struct value *ada_index_struct_field (int, struct value *, int,
struct type *);
@@ -678,7 +676,7 @@ coerce_unspec_val_to_type (struct value *val, struct type *type)
/* Make sure that the object size is not unreasonable before
trying to allocate some memory for it. */
- check_size (type);
+ ada_ensure_varsize_limit (type);
if (value_lazy (val)
|| TYPE_LENGTH (type) > TYPE_LENGTH (value_type (val)))
@@ -740,8 +738,8 @@ lim_warning (const char *format, ...)
i.e. if it would be a bad idea to allocate a value of this type in
GDB. */
-static void
-check_size (const struct type *type)
+void
+ada_ensure_varsize_limit (const struct type *type)
{
if (TYPE_LENGTH (type) > varsize_limit)
error (_("object size is larger than varsize-limit"));
@@ -2052,7 +2050,7 @@ ada_coerce_to_simple_array (struct value *arr)
if (arrVal == NULL)
error (_("Bounds unavailable for null array pointer."));
- check_size (TYPE_TARGET_TYPE (value_type (arrVal)));
+ ada_ensure_varsize_limit (TYPE_TARGET_TYPE (value_type (arrVal)));
return value_ind (arrVal);
}
else if (ada_is_constrained_packed_array_type (value_type (arr)))
@@ -7917,7 +7915,7 @@ ada_template_to_fixed_record_type_1 (struct type *type,
initialized, the type size may be completely bogus and
GDB may fail to allocate a value for it. So check the
size first before creating the value. */
- check_size (rtype);
+ ada_ensure_varsize_limit (rtype);
/* Using plain value_from_contents_and_address here
causes problems because we will end up trying to
resolve a type that is currently being
@@ -7965,7 +7963,7 @@ ada_template_to_fixed_record_type_1 (struct type *type,
large (due to an uninitialized variable in the inferior)
that it would cause an overflow when adding it to the
record size. */
- check_size (field_type);
+ ada_ensure_varsize_limit (field_type);
TYPE_FIELD_TYPE (rtype, f) = field_type;
TYPE_FIELD_NAME (rtype, f) = TYPE_FIELD_NAME (type, f);
@@ -10907,7 +10905,7 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
(ada_aligned_type
(ada_check_typedef (TYPE_TARGET_TYPE (type))));
}
- check_size (type);
+ ada_ensure_varsize_limit (type);
return value_zero (type, lval_memory);
}
else if (TYPE_CODE (type) == TYPE_CODE_INT)
diff --git a/gdb/ada-lang.h b/gdb/ada-lang.h
index ba3b9d8..964d569 100644
--- a/gdb/ada-lang.h
+++ b/gdb/ada-lang.h
@@ -162,6 +162,8 @@ struct ada_task_info
extern void *grow_vect (void *, size_t *, size_t, int);
+extern void ada_ensure_varsize_limit (const struct type *type);
+
extern int ada_get_field_index (const struct type *type,
const char *field_name,
int maybe_missing);
diff --git a/gdb/ada-valprint.c b/gdb/ada-valprint.c
index 6f68fae..1808cb6 100644
--- a/gdb/ada-valprint.c
+++ b/gdb/ada-valprint.c
@@ -1055,6 +1055,12 @@ ada_val_print_ref (struct type *type, const gdb_byte *valaddr,
if (ada_is_tagged_type (value_type (deref_val), 1))
deref_val = ada_tag_value_at_base_address (deref_val);
+ /* Make sure that the object does not have an unreasonable size
+ before trying to print it. This can happen for instance with
+ references to dynamic objects whose contents is uninitialized
+ (Eg: an array whose bounds are not set yet). */
+ ada_ensure_varsize_limit (value_type (deref_val));
+
val_print (value_type (deref_val),
value_contents_for_printing (deref_val),
value_embedded_offset (deref_val),
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index a0acd98..5e8953c 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2014-12-13 Joel Brobecker <brobecker@adacore.com>
+
+ * gdb.ada/str_uninit: New testcase.
+
2014-12-13 Jan Kratochvil <jan.kratochvil@redhat.com>
PR symtab/17642
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 <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"
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 <http://www.gnu.org/licenses/>.
+
+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 <http://www.gnu.org/licenses/>.
+
+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 <http://www.gnu.org/licenses/>.
+
+with System;
+
+package Pck is
+
+ procedure Do_Nothing (A : System.Address);
+
+ function Foos return String;
+
+end Pck;
--
1.9.1