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

[Elena Zannoni <ezannoni at redhat dot com>]

David Carlton writes:
 > 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.
 > 

Ahh. Good catch.

 > 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.
 > 

Yes, sorry, but also easier to review... :-) 

OK. 

Wait for Fernando's word on the tests.

Elena


 > 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;