# New Ticket Created by Mark Glines
# Please include the string: [perl #52462]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=52462 >
When doing a test for --gc=libc, I noticed test 10 of t/op/calling.t
was hanging. The test creates a FixedIntegerArray from the string "0,
0x20, 0x20, 0". The new_from_string() constructor relies on STRING*
buffers containing a trailing NULL (which isn't counted in the
"strlen" tally). The existence of that NULL is not a valid assumption
in the gc=libc case. Everything goes ok until the following code:
125 start = p;
126 elem = strtoul(p, &p, base);
127 --p;
128 i -= (p - start);
129 SELF.set_integer_keyed_int(n, elem);
130 break;
The string is 16 bytes long. On gc=<default>, the cstring buffer is
NULL terminated, and everything works fine. But the planets have
aligned toward my laptop, or whatever. So on gc=libc, the cstring
buffer happens to have a "1" directly afterwards in memory. So the
buffer actually looks like "0, 0x20, 0x20, 01", where the "1" is at
buffer[16]. In other words, directly after the valid area of the
buffer. But strtoul() doesn't know any better, so it sets &p to
&buffer[17], and the enclosing for() loop spins forever.
I've attached a fix. It isn't very pretty, and it probably really hurts
performance. But it fixes the hang, and allows the test script to
complete successfully. I am submitting it to RT in the hopes that
someone with better knowledge of parrot internals can come up with a
Better Way (tm).
Mark
Index: src/pmc/fixedintegerarray.pmc
===================================================================
--- src/pmc/fixedintegerarray.pmc (revision 26715)
+++ src/pmc/fixedintegerarray.pmc (working copy)
@@ -56,11 +56,15 @@
=cut
*/
- VTABLE PMC *new_from_string(STRING *rep, INTVAL flags) {
+ VTABLE PMC *new_from_string(STRING *rep_orig, INTVAL flags) {
const INTVAL type = SELF->vtable->base_type;
INTVAL n, elem, i, l;
char *p, *start;
int base;
+ /* the use of strtoul(), below, requires NULL termination. */
+ STRING *null = string_from_cstring(interp, "\0", 1);
+ STRING *rep = string_concat(interp, rep_orig, null, 0);
+ rep->strlen--;
if (flags & PObj_constant_FLAG)
SELF = constant_pmc_new(INTERP, type);
