Re: [PHP-DEV] Re: #20993 [Ver]: Element value changeswithoutasking

[Moriyoshi Koizumi]

Oops, the patch was wrong as the runtime occationally segfaults
in a case like:

<?php
  $a = 0;
  $a = &$a; /* is_ref=1, refcount=1 */
?>

Attached is the revised patch. Please try it out.

And the result of a tiny benchmark follows:

[Before patching]
1: 0.263245
2: 0.142505
3: 0.328045
4: 0.137149

[After patching]
1: 0.273811
2: 0.141965
3: 0.699429
4: 0.137010

Moriyoshi

> My proposal, was based on 2 things: fix or document. I'm sure Zeev/Andi had a
> good reason not to always separate, and that probably is performance.
> 
> IF this impacts overall performance very negatively, then maybe the better
> choice is to document it.
> 
> I'll try the patch though.
> 
> 
> With kind regards,
> 
> Melvyn Sopacua
> <?php include("not_reflecting_employers_views.txt"); ?>
> 
> 
> -- 
> PHP Development Mailing List <http://www.php.net/>
> To unsubscribe, visit: http://www.php.net/unsub.php
> 

Index: zend_execute.c
===================================================================
RCS file: /repository/Zend/zend_execute.c,v
retrieving revision 1.316.2.2
diff -u -r1.316.2.2 zend_execute.c
--- zend_execute.c      17 Nov 2002 22:00:32 -0000      1.316.2.2
+++ zend_execute.c      15 Dec 2002 06:47:03 -0000
@@ -65,6 +65,7 @@
 static void zend_extension_statement_handler(zend_extension *extension, zend_op_array 
*op_array TSRMLS_DC);
 static void zend_extension_fcall_begin_handler(zend_extension *extension, 
zend_op_array *op_array TSRMLS_DC);
 static void zend_extension_fcall_end_handler(zend_extension *extension, zend_op_array 
*op_array TSRMLS_DC);
+static int _zval_array_disref(zval **ppz);
 
 #define RETURN_VALUE_USED(opline) (!((opline)->result.u.EA.type & EXT_TYPE_UNUSED))
 
@@ -1816,6 +1817,7 @@
                                        } else if (PZVAL_IS_REF(*param)) {
                                                
zend_assign_to_variable_reference(NULL, get_zval_ptr_ptr(&EX(opline)->result, EX(Ts), 
BP_VAR_W), param, NULL TSRMLS_CC);
                                        } else {
+                                               _zval_array_disref(param);
                                                zend_assign_to_variable(NULL, 
&EX(opline)->result, NULL, *param, IS_VAR, EX(Ts) TSRMLS_CC);
                                        }
                                }
@@ -2480,4 +2482,59 @@
                }
        }
        zend_error(E_ERROR, "Arrived at end of main loop which shouldn't happen");
+}
+
+static int _zval_ref_check(zval **p, void *flag)
+{
+       if ((*p)->is_ref) {
+               *(int *)flag = 1;
+       }
+       _zval_array_disref(p);
+       return ZEND_HASH_APPLY_KEEP;
+}
+
+static void zval_dis_ref(zval **p)
+{
+       if ((*p)->is_ref) {
+               zval *newzv;
+               ALLOC_ZVAL(newzv);
+               *newzv = **p;
+               zval_copy_ctor(newzv);
+               newzv->refcount = 1;
+               newzv->is_ref = 0;
+
+               if ((*p)->refcount < 1) {
+                       zval_dtor((*p));
+                       FREE_ZVAL(*p);
+               }
+
+               *p = newzv;
+       } else {
+               ((*p))->refcount++;
+       }
+}
+
+static int _zval_array_disref(zval **ppz)
+{
+       TSRMLS_FETCH();
+       if ((*ppz)->type == IS_ARRAY) {
+               int flag = 0;
+               if ((*ppz)->value.ht == &EG(symbol_table)) {
+                       return SUCCESS;
+               }
+               zend_hash_apply_with_argument((*ppz)->value.ht, (apply_func_arg_t) 
+_zval_ref_check, (void *)&flag TSRMLS_CC);
+               if (flag) {
+                       zval *newzv, *tmp;
+                       ALLOC_ZVAL(newzv);
+                       *newzv = **ppz;
+                       ALLOC_HASHTABLE(newzv->value.ht);
+                       zend_hash_init(newzv->value.ht, 0, NULL, ZVAL_PTR_DTOR, 0);
+                       zend_hash_copy(newzv->value.ht, Z_ARRVAL_PP(ppz), 
+(copy_ctor_func_t) zval_dis_ref, (void *) &tmp, sizeof(zval *));
+                       zval_ptr_dtor(ppz);
+                       *ppz = newzv;
+                       newzv->is_ref = 0;
+                       newzv->refcount = 1;
+               }
+       } 
+       return SUCCESS;
 }

<?php
        function timediff($ts, $te) {
                list($ts_usec, $ts_sec) = explode(' ', $ts);
                list($te_usec, $te_sec) = explode(' ', $te);
                return ((float)$te_usec - (float)$ts_usec) + (float)( (int)$te_sec - 
(int)$ts_sec );
        }

        function test1( $ary ) {
                $ary[32048] = '3';
        }

        function test2( &$ary ) {
                $ary[32048] = '3';
        }

        for ($i=0; $i<100000; ++$i) { 
                $ary_org[$i] = str_repeat("\\", rand( 0, 12 )).sprintf("%08x", 
rand(-1,0x7fffffff));
        } 

        for ($i=0; $i<100000; ++$i) { 
                $ary_ref[$i] = &$ary_ref[$i];
        } 

        $ts = microtime();
        $ary = $ary_org;
        test1($ary);
        $te = microtime();
        printf("1: %f\n", timediff($ts, $te));

        $ts = microtime();
        $ary = $ary_org;
        test2($ary);
        $te = microtime();
        printf("2: %f\n", timediff($ts, $te));

        $ts = microtime();
        $ary = $ary_ref;
        test1($ary);
        $te = microtime();
        printf("3: %f\n", timediff($ts, $te));

        $ts = microtime();
        $ary = $ary_ref;
        test2($ary);
        $te = microtime();
        printf("4: %f\n", timediff($ts, $te));


?>

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