On Mon, 15 Dec 2014, Prathamesh Kulkarni wrote:
Caused segfault for pattern containing no captures at:
info.safe_grow_cleared(capture_max + 1); in capture_info::capture_info
artificial test-case:
(define_predicates integer_zerop)
(simplify
(bit_not integer_zerop)
{ build_zero_cst (type); })
* genmatch.c
(simplify::simplify): Set simplify::capture_max to 0 if pattern
contains no captures.
Hmm, I think I've seen this before and I think that vec should be
more robust. In fact
vecint v = vNULL;
v.quick_grow (0);
will segfault as called via
1572vecT, va_heap, vl_ptr::safe_grow (unsigned len MEM_STAT_DECL)
1573{
1574 unsigned oldlen = length ();
1575 gcc_checking_assert (oldlen = len);
1576 reserve_exact (len - oldlen PASS_MEM_STAT);
1577 m_vec-quick_grow (len);
in fact it is documented here:
/* Allocator for heap memory. Ensure there are at least RESERVE free
slots in V. If EXACT is true, grow exactly, else grow
exponentially. As a special case, if the vector had not been
allocated and and RESERVE is 0, no vector will be created. */
templatetypename T
inline void
va_heap::reserve (vecT, va_heap, vl_embed *v, unsigned reserve, bool
exact
MEM_STAT_DECL)
{
if we don't want to do that we should simply guard the safe_grow_cleared
call, not artificially increase the number of elements.
But I think the following is the best and also matches vec::truncate.
Boostrap regtest running on x86_64-unknown-linux-gnu.
Richard.
2014-12-15 Richard Biener rguent...@suse.de
* vec.h (vec::safe_grow): Guard against a grow to zero size.
Index: gcc/vec.h
===
--- gcc/vec.h (revision 218746)
+++ gcc/vec.h (working copy)
@@ -1574,7 +1574,10 @@ vecT, va_heap, vl_ptr::safe_grow (unsi
unsigned oldlen = length ();
gcc_checking_assert (oldlen = len);
reserve_exact (len - oldlen PASS_MEM_STAT);
- m_vec-quick_grow (len);
+ if (m_vec)
+m_vec-quick_grow (len);
+ else
+gcc_checking_assert (len == 0);
}
