[rfa+testsuite] don't search off the end of partial symbol tables

[David Carlton <carlton at math dot stanford dot edu>]

It turns out that the binary search in lookup_partial_symbol isn't too
careful about array boundaries: it looks for the first partial symbol
with the appropriate name (if there is one), and then looks, starting
at that position, for the partial symbol that is in the correct
namespace.  It stops when it finds a match or when it finds a symbol
with the wrong name.

So if you construct a partial symbol table whose last element has the
name you're looking for but is in the wrong namespace, then GDB will
read off the end of the psymtab.

The robustness of GDB with respect to partial symbol errors is a
constant sources of joy and delight.  Or something.  Jim: you'll be
happy to learn that I found this bug while running gdb.c++/psmang.exp
on a branch.

Here's a patch, and a test to catch it.  This patch is completely
orthogonal to (and much less important than) other patches of mine
that are awaiting review.

David Carlton
carlton@math.stanford.edu

2002-12-16  David Carlton  <carlton@math.stanford.edu>

	* symtab.c (lookup_partial_symbol): Don't search past the end of
	the partial symbols.

2002-12-16  David Carlton  <carlton@math.stanford.edu>

	* gdb.base/psymtab.exp: New file.
	* gdb.base/psymtab1.c: Ditto.
	* gdb.base/psymtab2.c: Ditto.

Index: symtab.c
===================================================================
RCS file: /cvs/src/src/gdb/symtab.c,v
retrieving revision 1.81
diff -u -p -r1.81 symtab.c
--- symtab.c	5 Dec 2002 21:26:57 -0000	1.81
+++ symtab.c	17 Dec 2002 00:33:20 -0000
@@ -1300,7 +1300,7 @@ lookup_partial_symbol (struct partial_sy
 {
   struct partial_symbol *temp;
   struct partial_symbol **start, **psym;
-  struct partial_symbol **top, **bottom, **center;
+  struct partial_symbol **top, **real_top, **bottom, **center;
   int length = (global ? pst->n_global_syms : pst->n_static_syms);
   int do_linear_search = 1;
   
@@ -1323,6 +1323,7 @@ lookup_partial_symbol (struct partial_sy
 
       bottom = start;
       top = start + length - 1;
+      real_top = top;
       while (top > bottom)
 	{
 	  center = bottom + (top - bottom) / 2;
@@ -1348,7 +1349,7 @@ lookup_partial_symbol (struct partial_sy
       /* djb - 2000-06-03 - Use SYMBOL_MATCHES_NAME, not a strcmp, so
 	 we don't have to force a linear search on C++. Probably holds true
 	 for JAVA as well, no way to check.*/
-      while (SYMBOL_MATCHES_NAME (*top,name))
+      while (top <= real_top && SYMBOL_MATCHES_NAME (*top,name))
 	{
 	  if (SYMBOL_NAMESPACE (*top) == namespace)
 	    {
Index: gdb.base/psymtab.exp
--- /dev/null	Thu Apr 11 07:25:15 2002
+++ /extra/gdb/working/src/gdb/testsuite/gdb.base/psymtab.exp	Mon Dec 16 16:44:17 2002
@@ -0,0 +1,72 @@
+# Copyright 2002 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.  
+
+# Please email any bugs, comments, and/or additions to this file to:
+# bug-gdb@prep.ai.mit.edu
+
+# This file is part of the gdb testsuite
+
+# This is intended to be a repository for tests that partial symbols
+# are working properly.  If multiple tests are added, make sure that
+# you exit and restart GDB between tests.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+#
+# test running programs
+#
+
+set prms_id 0
+set bug_id 0
+
+if { [skip_cplus_tests] } { continue }
+
+set testfile "psymtab"
+set binfile ${objdir}/${subdir}/${testfile}
+
+if  { [gdb_compile "${srcdir}/${subdir}/${testfile}1.c" "${testfile}1.o" object {debug}] != "" } {
+     gdb_suppress_entire_file "Testcase compile failed, so all tests in this file will automatically fail."
+}
+
+if  { [gdb_compile "${srcdir}/${subdir}/${testfile}2.c" "${testfile}2.o" object {debug}] != "" } {
+     gdb_suppress_entire_file "Testcase compile failed, so all tests in this file will automatically fail."
+}
+
+if  { [gdb_compile "${testfile}1.o ${testfile}2.o" ${binfile} executable {debug}] != "" } {
+     gdb_suppress_entire_file "Testcase compile failed, so all tests in this file will automatically fail."
+}
+
+# Create and source the file that provides information about the compiler
+# used to compile the test case.
+if [get_compiler_info ${binfile}] {
+    return -1;
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# This test is looking for a bug that manifested itself when GDB was
+# looking for a partial symbol such that there wasn't such a partial
+# symbol in the psymtab, but such that the last psym in the psymtab
+# had the right name but the wrong namespace.  Here, searching for
+# zzz::dummy currently causes a search for 'zzz' in STRUCT_NAMESPACE
+# without a preceding search for 'zzz' in VAR_NAMESPACE.
+
+gdb_test "break zzz::dummy" "Can't find member of namespace, class, struct, or union named \"zzz::dummy\"\r\n.*" "Don't search past end of psymtab."
Index: gdb.base/psymtab1.c
--- /dev/null	Thu Apr 11 07:25:15 2002
+++ /extra/gdb/working/src/gdb/testsuite/gdb.base/psymtab1.c	Mon Dec 16 16:29:37 2002
@@ -0,0 +1,4 @@
+int main ()
+{
+  return 0;
+}
Index: gdb.base/psymtab2.c
--- /dev/null	Thu Apr 11 07:25:15 2002
+++ /extra/gdb/working/src/gdb/testsuite/gdb.base/psymtab2.c	Mon Dec 16 16:29:49 2002
@@ -0,0 +1,3 @@
+extern int zzz;
+
+int zzz = 123;