[PATCH] Fix MI crash with Ada string access
Tom Tromey
tromey@adacore.com
Thu Aug 13 20:53:29 GMT 2020
I happened to notice that using -var-create at a certain spot in an
Ada program caused a crash. This happens because
ada_get_decoded_value can return NULL -- in particular, deeper in the
code it can hit this return in ada_type_of_array:
descriptor = desc_bounds (arr);
if (value_as_long (descriptor) == 0)
return NULL;
This patch avoids the crash by handling this NULL return.
gdb/ChangeLog
2020-08-13 Tom Tromey <tromey@adacore.com>
* ada-varobj.c (ada_varobj_decode_var): Handle case where
ada_get_decoded_value returns NULL.
gdb/testsuite/ChangeLog
2020-08-13 Tom Tromey <tromey@adacore.com>
* gdb.ada/mi_var_access.exp: New file.
* gdb.ada/mi_var_access/mi_access.adb: New file.
* gdb.ada/mi_var_access/pck.adb: New file.
* gdb.ada/mi_var_access/pck.ads: New file.
---
gdb/ChangeLog | 5 ++
gdb/ada-varobj.c | 8 +--
gdb/testsuite/ChangeLog | 7 +++
gdb/testsuite/gdb.ada/mi_var_access.exp | 52 +++++++++++++++++++
.../gdb.ada/mi_var_access/mi_access.adb | 37 +++++++++++++
gdb/testsuite/gdb.ada/mi_var_access/pck.adb | 26 ++++++++++
gdb/testsuite/gdb.ada/mi_var_access/pck.ads | 23 ++++++++
7 files changed, 154 insertions(+), 4 deletions(-)
create mode 100644 gdb/testsuite/gdb.ada/mi_var_access.exp
create mode 100644 gdb/testsuite/gdb.ada/mi_var_access/mi_access.adb
create mode 100644 gdb/testsuite/gdb.ada/mi_var_access/pck.adb
create mode 100644 gdb/testsuite/gdb.ada/mi_var_access/pck.ads
diff --git a/gdb/ada-varobj.c b/gdb/ada-varobj.c
index f67fe5002a3..a72653af37a 100644
--- a/gdb/ada-varobj.c
+++ b/gdb/ada-varobj.c
@@ -63,10 +63,10 @@ static void
ada_varobj_decode_var (struct value **value_ptr, struct type **type_ptr)
{
if (*value_ptr)
- {
- *value_ptr = ada_get_decoded_value (*value_ptr);
- *type_ptr = ada_check_typedef (value_type (*value_ptr));
- }
+ *value_ptr = ada_get_decoded_value (*value_ptr);
+
+ if (*value_ptr != nullptr)
+ *type_ptr = ada_check_typedef (value_type (*value_ptr));
else
*type_ptr = ada_get_decoded_type (*type_ptr);
}
diff --git a/gdb/testsuite/gdb.ada/mi_var_access.exp b/gdb/testsuite/gdb.ada/mi_var_access.exp
new file mode 100644
index 00000000000..5ffc0ae8772
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/mi_var_access.exp
@@ -0,0 +1,52 @@
+# Copyright 2020 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"
+
+if {[skip_ada_tests]} {
+ return -1
+}
+
+standard_ada_testfile mi_access
+
+load_lib mi-support.exp
+set MIFLAGS "-i=mi"
+
+if {[gdb_compile_ada "${srcfile}" "${binfile}" executable debug] != "" } {
+ return -1
+}
+
+if {[mi_gdb_start]} {
+ continue
+}
+
+mi_delete_breakpoints
+mi_gdb_reinitialize_dir $srcdir/$subdir
+mi_gdb_load ${binfile}
+
+if ![mi_run_to_main] then {
+ fail "cannot run to main, testcase aborted"
+ return 0
+}
+
+set bp_location [gdb_get_line_number "STOP" ${testdir}/mi_access.adb]
+mi_continue_to_line \
+ "mi_access.adb:$bp_location" \
+ "stop at start of mi_access"
+
+# The bug was that creating a varobj for A_String_Access would crash.
+mi_gdb_test "-var-create A_String_Access * A_String_Access" \
+ "\\^done,name=\"A_String_Access\",numchild=\"1\",.*" \
+ "Create varobj"
diff --git a/gdb/testsuite/gdb.ada/mi_var_access/mi_access.adb b/gdb/testsuite/gdb.ada/mi_var_access/mi_access.adb
new file mode 100644
index 00000000000..d5f5f881463
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/mi_var_access/mi_access.adb
@@ -0,0 +1,37 @@
+-- Copyright 2020 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 Mi_Access is
+ A_String : String (3 .. 5) := "345"; -- STOP
+ A_String_Access : String_Access;
+ A_Pointer : Pointer;
+begin
+ Do_Nothing (A_String'Address);
+ A_String (4) := '6';
+ A_String_Access := Copy (A_String);
+ A_Pointer.P := A_String_Access;
+ Do_Nothing (A_String_Access'Address);
+ A_String_Access (4) := 'a';
+ Do_Nothing (A_Pointer'Address);
+ A_String_Access := Copy("Hi");
+ A_Pointer.P := A_String_Access;
+ Do_Nothing (A_String_Access'Address);
+ A_String_Access := null;
+ A_Pointer.P := null;
+ Do_Nothing (A_Pointer'Address);
+ Do_Nothing (A_String'Address);
+end Mi_Access;
diff --git a/gdb/testsuite/gdb.ada/mi_var_access/pck.adb b/gdb/testsuite/gdb.ada/mi_var_access/pck.adb
new file mode 100644
index 00000000000..9aff885f65b
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/mi_var_access/pck.adb
@@ -0,0 +1,26 @@
+-- Copyright 2020 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
+ function Copy (S : String) return String_Access is
+ begin
+ return new String'(S);
+ end Copy;
+
+ procedure Do_Nothing (A : System.Address) is
+ begin
+ null;
+ end Do_Nothing;
+end Pck;
diff --git a/gdb/testsuite/gdb.ada/mi_var_access/pck.ads b/gdb/testsuite/gdb.ada/mi_var_access/pck.ads
new file mode 100644
index 00000000000..307a0aacd6d
--- /dev/null
+++ b/gdb/testsuite/gdb.ada/mi_var_access/pck.ads
@@ -0,0 +1,23 @@
+-- Copyright 2020 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
+ type String_Access is access all String;
+ type Pointer is record P : String_Access; end record;
+
+ function Copy (S : String) return String_Access;
+ procedure Do_Nothing (A : System.Address);
+end Pck;
--
2.26.2
More information about the Gdb-patches
mailing list