Fix RC tracking of op1 of FETCH_OBJ

Fixes GH-17151

Author: iluuu1994

Zend/Optimizer/zend_inference.c

@@ -3767,6 +3767,36 @@ static zend_always_inline zend_result _zend_update_type_info(
 		case ZEND_FETCH_OBJ_W:
 		case ZEND_FETCH_OBJ_UNSET:
 		case ZEND_FETCH_OBJ_FUNC_ARG:
+			if (ssa_op->op1_def >= 0) {
+				tmp = t1;
+				if (tmp & (MAY_BE_RC1|MAY_BE_RCN)) {
+					do {
+						const zend_class_entry *ce = NULL;
+
+						if (opline->op1_type == IS_UNUSED) {
+							ce = op_array->scope;
+						} else if (ssa_op->op1_use >= 0 && !ssa->var_info[ssa_op->op1_use].is_instanceof) {
+							ce = ssa->var_info[ssa_op->op1_use].ce;
+						}
+
+						// FIXME: Could be more permissive by checking for corresponding bp type,
+						// handler, hook and magic method.
+						if (ce
+						 && !ce->create_object
+						 && ce->default_object_handlers == &std_object_handlers) {
+							const zend_property_info *prop_info = zend_fetch_prop_info(op_array, ssa, opline, ssa_op);
+							if ((prop_info && !prop_info->hooks)
+							 || (!ce->__get && !ce->__set && !ce->__isset && !ce->__unset)) {
+								break;
+							}
+						}
+
+						tmp |= (MAY_BE_RC1|MAY_BE_RCN);
+					} while (0);
+				}
+				UPDATE_SSA_TYPE(tmp, ssa_op->op1_def);
+				COPY_SSA_OBJ_TYPE(ssa_op->op1_use, ssa_op->op1_def);
+			}
 			if (ssa_op->result_def >= 0) {
 				uint32_t tmp = 0;
 				ce = NULL;

Zend/Optimizer/zend_ssa.c

@@ -794,7 +794,18 @@ static zend_always_inline int _zend_ssa_rename_op(const zend_op_array *op_array,
 					}
 				}
 			}
+			break;
 		}
+		case ZEND_FETCH_OBJ_R:
+		case ZEND_FETCH_OBJ_IS:
+		case ZEND_FETCH_OBJ_RW:
+		case ZEND_FETCH_OBJ_W:
+		case ZEND_FETCH_OBJ_UNSET:
+		case ZEND_FETCH_OBJ_FUNC_ARG:
+			if ((build_flags & ZEND_SSA_RC_INFERENCE) && (opline->op1_type & (IS_CV|IS_VAR|IS_TMP_VAR))) {
+				goto add_op1_def;
+			}
+			break;
 		default:
 			break;
 	}

ext/opcache/jit/zend_jit_ir.c

@@ -14591,6 +14591,9 @@ static int zend_jit_fetch_obj(zend_jit_ctx         *jit,
 			if (on_this) {
 				op1_info &= ~MAY_BE_RC1;
 			}
+			if (ssa_op->op1_def >= 0) {
+				op1_info |= (ssa->var_info[ssa_op->op1_def].type & (MAY_BE_RC1|MAY_BE_RCN));
+			}
 			jit_FREE_OP(jit, opline->op1_type, opline->op1, op1_info, opline);
 		}
 	}

ext/opcache/tests/jit/gh17151_1.phpt

@@ -0,0 +1,22 @@
+--TEST--
+GH-17151: ZEND_FETCH_OBJ_R may modify RC of op1
+--FILE--
+<?php
+
+class C {
+    public function __get($name) {
+        return $this;
+    }
+}
+
+function test() {
+    $x = (new C)->bar;
+    var_dump($x);
+}
+
+test();
+
+?>
+--EXPECTF--
+object(C)#%d (0) {
+}

ext/opcache/tests/jit/gh17151_2.phpt

@@ -0,0 +1,29 @@
+--TEST--
+GH-17151: ZEND_FETCH_OBJ_R may modify RC of op1
+--FILE--
+<?php
+
+class C {
+    public static $prop;
+
+    public function __get($name) {
+        C::$prop = null;
+    }
+
+    public function __destruct() {
+        echo __METHOD__, "\n";
+    }
+}
+
+function test() {
+    C::$prop = new C();
+    C::$prop->bar;
+}
+
+test();
+echo "Done\n";
+
+?>
+--EXPECT--
+C::__destruct
+Done