New subject: wmc and ElectricFence

18 Dec 2002


      Sure enough, valgrind finds something to complain about:
$ cd dlls/kernel
$ make messages/winerr_enu.mc.rc
LD_LIBRARY_PATH="../../library:../../unicode:$LD_LIBRARY_PATH" valgrind ../../tools/wmc/wmc -i -U -H 
/dev/null -o messages/winerr_enu.mc.rc messages/winerr_enu.mc
...
==7935== Invalid read of size 4
==7935==    at 0x804B7A4: yyparse (./mcy.y:232)
==7935==    by 0x804A4B3: main (wmc.c:256)
==7935==    by 0x420158D3: __libc_start_main (in /lib/i686/libc-2.2.93.so)
==7935==    by 0x8048E50: (within /home/dank/wine-20021125/tools/wmc/wmc)
==7935==    Address 0x4106E5E4 is 8 bytes inside a block of size 24 free'd
==7935==    at 0x4015D715: free (vg_clientfuncs.c:182)
==7935==    by 0x804B79A: yyparse (./mcy.y:231)
==7935==    by 0x804A4B3: main (wmc.c:256)
==7935==    by 0x420158D3: __libc_start_main (in /lib/i686/libc-2.2.93.so)
Recompiling wmc with -O0 and rerunning, I get
==7970== Invalid read of size 4
==7970==    at 0x804C73E: yyparse (./mcy.y:232)
==7970==    by 0x804AA3B: main (wmc.c:256)
==7970==    by 0x420158D3: __libc_start_main (in /lib/i686/libc-2.2.93.so)
==7970==    by 0x8048D6C: (within /home/dank/wine-20021125/tools/wmc/wmc)
==7970==    Address 0x4106E5E4 is 8 bytes inside a block of size 24 free'd
==7970==    at 0x4015D715: free (vg_clientfuncs.c:182)
==7970==    by 0x804D2F4: do_add_token (./mcy.y:434)
==7970==    by 0x804C731: yyparse (./mcy.y:231)
==7970==    by 0x804AA3B: main (wmc.c:256)
Looking at y.tab.c, I see the bug is that do_add_token
sometimes frees its 2nd argument, which trips up the
following line sometimes.  Here's the sequence that crashed:
do_add_token(tok_language, yyvsp[-6].tok, "language");
   if(!find_language(yyvsp[-6].tok->token) && !find_cpxlat(yyvsp[-6].tok->token))
These come from mcy.y:
do_add_token(tok_language, $1, "language");
   if(!find_language($1->token) && !find_cpxlat($1->token))
Can someone who knows wmc have a look?
- Dan

re: wmc and ElectricFence