Hi,
Valgrind memory checker detects the following bug in
vim-7.1 (patches 1-68) on Linux x86.
==7405== Conditional jump or move depends on uninitialised value(s)
==7405== at 0x8152C76: spell_move_to (spell.c:2150)
==7405== by 0x813DC28: win_line (screen.c:3040)
==7405== by 0x813BC14: win_update (screen.c:1760)
==7405== by 0x813A022: update_screen (screen.c:522)
==7405== by 0x80CD213: main_loop (main.c:1109)
==7405== by 0x80CCF62: main (main.c:939)
==7405==
==7405== Conditional jump or move depends on uninitialised value(s)
==7405== at 0x8152C8D: spell_move_to (spell.c:2157)
==7405== by 0x813DC28: win_line (screen.c:3040)
==7405== by 0x813BC14: win_update (screen.c:1760)
==7405== by 0x813A022: update_screen (screen.c:522)
==7405== by 0x80CD213: main_loop (main.c:1109)
==7405== by 0x80CCF62: main (main.c:939)
Looking at the code, 'can_spell' variable is meant to be initialized
at line spell.c:2148 and then used at line spell.c:2150 and
spell.c:2157:
spell.c:
2144 # ifdef FEAT_SYN_HL
2145 if (has_syntax)
2146 {
2147 col = (int)(p - buf);
INIT 2148 (void)syn_get_id(wp, lnum, (colnr_T)col,
2149 FALSE, &can_spell);
USE 2150 if (!can_spell)
2151 attr = HLF_COUNT;
2152 }
2153 else
2154 #endif
2155 can_spell = TRUE;
2156
USE 2157 if (can_spell)
2158 {
However, there are several paths inside syn_get_id()->get_syntax_attr()
where 'can_spell' may not be initialized (which does happens in practice
since valgrind detects it).
Bug happens with syntax highlighting + spelling checker on a C file.
I can reproduce it 100% of the time by doing something a bit silly
(but that's often how we find bugs): visual select all lines of a
C file, use J command to join all lines (then valgrind detects bug).
I attach a patch which ensures default initialization of 'can_spell'
variable.
-- Dominique
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Index: syntax.c
===================================================================
RCS file: /cvsroot/vim/vim7/src/syntax.c,v
retrieving revision 1.70
diff -c -r1.70 syntax.c
*** syntax.c 26 Jul 2007 20:58:19 -0000 1.70
--- syntax.c 12 Aug 2007 17:02:55 -0000
***************
*** 1727,1732 ****
--- 1727,1735 ----
{
int attr = 0;
+ if (can_spell != NULL)
+ *can_spell = FALSE; /* default value */
+
/* check for out of memory situation */
if (syn_buf->b_sst_array == NULL)
return 0;
