From: anton at samba dot org
Operating system: Linux/RHEL5.2/PowerPC64
PHP version: 5.2.6
PHP Bug Type: Compile Failure
Bug description: Pointer aliasing issue results in miscompile on gcc4.4
Description:
------------
A recent checkout of gcc4.4 miscompiles php on PowerPC64. The following
function reads from p via long * and stores to p via void * which violates
aliasing rules:
static inline void zend_ptr_stack_clear_multiple(TSRMLS_D)
{
void **p = EG(argument_stack).top_element-2;
int delete_count = (int)(zend_uintptr_t) *p;
EG(argument_stack).top -= (delete_count+2);
while (--delete_count>=0) {
zval *q = *(zval **)(--p);
*p = NULL;
zval_ptr_dtor(&q);
}
EG(argument_stack).top_element = p;
}
More details can be found at:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37824
We can remove the (zval **) cast so that we read and write via void *p and
fix the aliasing issue. I will attach a patch.
--
Edit bug report at http://bugs.php.net/?id=46311&edit=1
--
Try a CVS snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=46311&r=trysnapshot52
Try a CVS snapshot (PHP 5.3):
http://bugs.php.net/fix.php?id=46311&r=trysnapshot53
Try a CVS snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=46311&r=trysnapshot60
Fixed in CVS: http://bugs.php.net/fix.php?id=46311&r=fixedcvs
Fixed in release:
http://bugs.php.net/fix.php?id=46311&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=46311&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=46311&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=46311&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=46311&r=support
Expected behavior: http://bugs.php.net/fix.php?id=46311&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=46311&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=46311&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=46311&r=globals
PHP 4 support discontinued: http://bugs.php.net/fix.php?id=46311&r=php4
Daylight Savings: http://bugs.php.net/fix.php?id=46311&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=46311&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=46311&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=46311&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=46311&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=46311&r=mysqlcfg
