Re: [PATCH] Fix segfault on empty else

Andrew STUBBS
2006-07-07T11:08:30Z

[-- Attachment #1: Type: text/plain, Size: 339 bytes --]

Daniel Jacobowitz wrote:
> Does this work better?

Yes much better, thanks. It now runs all the tests, no matter what, and
reports crashes as failures. The only exception is the very last one,
which really is unresolved following the failure of the previous test.

How about the attached patch then?

:ADDPATCH testsuite:

Andrew Stubbs

[-- Attachment #2: empty-else-test.patch --]
[-- Type: text/plain, Size: 3652 bytes --]

2006-07-07 Andrew Stubbs <andrew.stubbs@st.com>

* gdb.base/ifelse.exp: New file.

Index: src/gdb/testsuite/gdb.base/ifelse.exp
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ src/gdb/testsuite/gdb.base/ifelse.exp 2006-07-07 11:59:28.000000000 +0100
@@ -0,0 +1,105 @@
+# Copyright 2006 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 2 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, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+# This test checks that the if .. else .. end construct works and may
+# contain empty bodies without crashing.
+
+if $tracelevel then {
+ strace $tracelevel
+}
+
+gdb_exit
+gdb_start
+
+# First test that the if command works with an empty body
+# Test with different conditions because the body is ignored
+# if it is not executed.
+
+# with true condition
+set message "if 1 with empty body"
+gdb_test_multiple "if 1\nend\necho got here\\n" $message {
+ -re ".*got here.*$gdb_prompt $" {pass $message}
+ eof {
+ fail "$message (crashed)"
+ gdb_exit
+ gdb_start
+ }
+}
+
+# with false condition
+set message "if 0 with empty body"
+gdb_test_multiple "if 0\nend\necho got here\\n" $message {
+ -re ".*got here.*$gdb_prompt $" {pass $message}
+ eof {
+ fail "$message (crashed)"
+ gdb_exit
+ gdb_start
+ }
+}
+
+# Second, do the same tests with an empty else body.
+# This fails in GDB <=6.5
+
+# Unfortunately it was an uninitialised memory problem so
+# sometimes it just works. Preceed it with an if else end with
+# bodies and hopefully the memory with be dirty and the problem
+# will show itself (this works at time of writing).
+
+gdb_test "if 1\necho true\\n\nelse\necho false\\n\nend" "true" ""
+
+# with true condition
+set message "if 1 .. else with empty body"
+gdb_test_multiple "if 1\nelse\nend\necho got here\\n" $message {
+ -re ".*got here.*$gdb_prompt $" {pass $message}
+ eof {
+ fail "$message (crashed)"
+ gdb_exit
+ gdb_start
+ }
+}
+
+# dirty memory
+gdb_test "if 1\necho true\\n\nelse\necho false\\n\nend" "true" ""
+
+# with false condition
+set message "if 0 .. else with empty body"
+gdb_test_multiple "if 0\nelse\nend\necho got here\\n" $message {
+ -re ".*got here.*$gdb_prompt $" {pass $message}
+ eof {
+ fail "$message (crashed)"
+ gdb_exit
+ gdb_start
+ }
+}
+
+gdb_test "set confirm off" "" ""
+
+# Test that a define with an empty else can be replaced.
+# If there is memory corruption then free will fail.
+# dirty memory
+gdb_test "if 1\necho true\\n\nelse\necho false\\n\nend" "true" ""
+# create
+gdb_test "define abc\nif 1\nelse\nend\nend" "" "create define with empty else"
+# call (note that condition is 1 so should pass)
+gdb_test "abc" "" "call original define"
+# replace
+set message "replace define with if .. else with empty body"
+gdb_test_multiple "define abc\necho got here\\n\nend" $message {
+ -re "$gdb_prompt $" {pass $message}
+ eof {fail "$message (crashed)"}
+}
+# call
+gdb_test "abc" "got here" "call replacement define"