php-src/ext/opcache/Optimizer/pass1_5.c

/* pass 1
 * - substitute persistent constants (true, false, null, etc)
 * - perform compile-time evaluation of constant binary and unary operations
 * - optimize series of ADD_STRING and/or ADD_CHAR
 * - convert CAST(IS_BOOL,x) into BOOL(x)
 * - pre-evaluate constant function calls
 */

#if ZEND_EXTENSION_API_NO > PHP_5_2_X_API_NO
# define ZEND_IS_CONSTANT_TYPE(t)	((t) == IS_CONSTANT)
#else
# define ZEND_IS_CONSTANT_TYPE(t)	((t) == IS_CONSTANT)
#endif

if (ZEND_OPTIMIZER_PASS_1 & OPTIMIZATION_LEVEL) {
	int i = 0;
	zend_op *opline = op_array->opcodes;
	zend_op *end = opline + op_array->last;
	zend_bool collect_constants = (op_array == &ctx->script->main_op_array);

	while (opline < end) {
		switch (opline->opcode) {
		case ZEND_ADD:
		case ZEND_SUB:
		case ZEND_MUL:
		case ZEND_DIV:
		case ZEND_MOD:
#if ZEND_EXTENSION_API_NO >= PHP_5_6_X_API_NO
		case ZEND_POW:
#endif
		case ZEND_SL:
		case ZEND_SR:
		case ZEND_CONCAT:
		case ZEND_IS_EQUAL:
		case ZEND_IS_NOT_EQUAL:
		case ZEND_IS_SMALLER:
		case ZEND_IS_SMALLER_OR_EQUAL:
		case ZEND_IS_IDENTICAL:
		case ZEND_IS_NOT_IDENTICAL:
		case ZEND_BW_OR:
		case ZEND_BW_AND:
		case ZEND_BW_XOR:
		case ZEND_BOOL_XOR:
			if (ZEND_OP1_TYPE(opline) == IS_CONST &&
				ZEND_OP2_TYPE(opline) == IS_CONST) {
				/* binary operation with constant operands */
				int (*binary_op)(zval *result, zval *op1, zval *op2 TSRMLS_DC) = get_binary_op(opline->opcode);
				zend_uint tv = ZEND_RESULT(opline).var;		/* temporary variable */
				zval result;
				int er;

				if (opline->opcode == ZEND_DIV &&
					Z_TYPE(ZEND_OP2_LITERAL(opline)) == IS_LONG &&
					Z_LVAL(ZEND_OP2_LITERAL(opline)) == 0) {
					/* div by 0 */
					break;
				}
				er = EG(error_reporting);
				EG(error_reporting) = 0;
				/* evaluate constant expression */
				if (binary_op(&result, &ZEND_OP1_LITERAL(opline), &ZEND_OP2_LITERAL(opline) TSRMLS_CC) != SUCCESS) {
					EG(error_reporting) = er;
					break;
				}
				EG(error_reporting) = er;
				literal_dtor(&ZEND_OP1_LITERAL(opline));
				literal_dtor(&ZEND_OP2_LITERAL(opline));
				MAKE_NOP(opline);

				replace_tmp_by_const(op_array, opline + 1, tv, &result TSRMLS_CC);
			}
			break;

		case ZEND_CAST:
			if (ZEND_OP1_TYPE(opline) == IS_CONST &&
				opline->extended_value != IS_ARRAY &&
				opline->extended_value != IS_OBJECT &&
				opline->extended_value != IS_RESOURCE) {
				/* cast of constant operand */
				zend_uint tv = ZEND_RESULT(opline).var;		/* temporary variable */
				zval res;
				res = ZEND_OP1_LITERAL(opline);
				zval_copy_ctor(&res);
				switch (opline->extended_value) {
					case IS_NULL:
						convert_to_null(&res);
						break;
					case _IS_BOOL:
						convert_to_boolean(&res);
						break;
					case IS_LONG:
						convert_to_long(&res);
						break;
					case IS_DOUBLE:
						convert_to_double(&res);
						break;
					case IS_STRING:
						convert_to_string(&res);
						break;
				}

				literal_dtor(&ZEND_OP1_LITERAL(opline));
				MAKE_NOP(opline);

				if (opline->result_type == IS_TMP_VAR) {
					replace_tmp_by_const(op_array, opline + 1, tv, &res TSRMLS_CC);
				} else /* if (opline->result_type == IS_VAR) */ {
					replace_var_by_const(op_array, opline + 1, tv, &res TSRMLS_CC);
				}
			} else if (opline->extended_value == _IS_BOOL) {
				/* T = CAST(X, IS_BOOL) => T = BOOL(X) */
				opline->opcode = ZEND_BOOL;
				opline->extended_value = 0;
			}
			break;

		case ZEND_BW_NOT:
		case ZEND_BOOL_NOT:
			if (ZEND_OP1_TYPE(opline) == IS_CONST) {
				/* unary operation on constant operand */
				unary_op_type unary_op = get_unary_op(opline->opcode);
				zval result;
				zend_uint tv = ZEND_RESULT(opline).var;		/* temporary variable */
				int er;

				er = EG(error_reporting);
				EG(error_reporting) = 0;
#if ZEND_EXTENSION_API_NO < PHP_5_3_X_API_NO
				if (unary_op(&result, &ZEND_OP1_LITERAL(opline)) != SUCCESS) {
#else
				if (unary_op(&result, &ZEND_OP1_LITERAL(opline) TSRMLS_CC) != SUCCESS) {
#endif
					EG(error_reporting) = er;
					break;
				}
				EG(error_reporting) = er;
				literal_dtor(&ZEND_OP1_LITERAL(opline));
				MAKE_NOP(opline);

				replace_tmp_by_const(op_array, opline + 1, tv, &result TSRMLS_CC);
			}
			break;

		case ZEND_ADD_STRING:
		case ZEND_ADD_CHAR:
			{
				zend_op *next_op = opline + 1;
				int requires_conversion = (opline->opcode == ZEND_ADD_CHAR? 1 : 0);
				size_t final_length = 0;
				zend_string *str;
				char *ptr;
				zend_op *last_op;

				/* There is always a ZEND_RETURN at the end
				if (next_op>=end) {
					break;
				}
				*/
				while (next_op->opcode == ZEND_ADD_STRING || next_op->opcode == ZEND_ADD_CHAR) {
					if (ZEND_RESULT(opline).var != ZEND_RESULT(next_op).var) {
						break;
					}
					if (next_op->opcode == ZEND_ADD_CHAR) {
						final_length += 1;
					} else { /* ZEND_ADD_STRING */
						final_length += Z_STRLEN(ZEND_OP2_LITERAL(next_op));
					}
					next_op++;
				}
				if (final_length == 0) {
					break;
				}
				last_op = next_op;
				final_length += (requires_conversion? 1 : Z_STRLEN(ZEND_OP2_LITERAL(opline)));
				str = STR_ALLOC(final_length, 0);
				ptr = str->val;
				ptr[final_length] = '\0';
				if (requires_conversion) { /* ZEND_ADD_CHAR */
					char chval = (char)Z_LVAL(ZEND_OP2_LITERAL(opline));

					ZVAL_NEW_STR(&ZEND_OP2_LITERAL(opline), str);
					ptr[0] = chval;
					opline->opcode = ZEND_ADD_STRING;
					ptr++;
				} else { /* ZEND_ADD_STRING */
					memcpy(ptr, Z_STRVAL(ZEND_OP2_LITERAL(opline)), Z_STRLEN(ZEND_OP2_LITERAL(opline)));
					STR_RELEASE(Z_STR(ZEND_OP2_LITERAL(opline)));
					Z_STR(ZEND_OP2_LITERAL(opline)) = str;
					ptr += Z_STRLEN(ZEND_OP2_LITERAL(opline));
				}
				Z_STRLEN(ZEND_OP2_LITERAL(opline)) = final_length;
				next_op = opline + 1;
				while (next_op < last_op) {
					if (next_op->opcode == ZEND_ADD_STRING) {
						memcpy(ptr, Z_STRVAL(ZEND_OP2_LITERAL(next_op)), Z_STRLEN(ZEND_OP2_LITERAL(next_op)));
						ptr += Z_STRLEN(ZEND_OP2_LITERAL(next_op));
						literal_dtor(&ZEND_OP2_LITERAL(next_op));
					} else { /* ZEND_ADD_CHAR */
						*ptr = (char)Z_LVAL(ZEND_OP2_LITERAL(next_op));
						ptr++;
					}
					MAKE_NOP(next_op);
					next_op++;
				}
				if (!((ZEND_OPTIMIZER_PASS_5|ZEND_OPTIMIZER_PASS_10) & OPTIMIZATION_LEVEL)) {
					/* NOP removal is disabled => insert JMP over NOPs */
					if (last_op-opline >= 3) { /* If we have more than 2 NOPS then JMP over them */
						(opline + 1)->opcode = ZEND_JMP;
						ZEND_OP1(opline + 1).opline_num = last_op - op_array->opcodes; /* that's OK even for ZE2, since opline_num's are resolved in pass 2 later */
					}
				}
			}
			break;

		case ZEND_FETCH_CONSTANT:
			if (ZEND_OP1_TYPE(opline) == IS_UNUSED &&
				ZEND_OP2_TYPE(opline) == IS_CONST &&
				Z_TYPE(ZEND_OP2_LITERAL(opline)) == IS_STRING &&
				Z_STRLEN(ZEND_OP2_LITERAL(opline)) == sizeof("__COMPILER_HALT_OFFSET__") - 1 &&
				memcmp(Z_STRVAL(ZEND_OP2_LITERAL(opline)), "__COMPILER_HALT_OFFSET__", sizeof("__COMPILER_HALT_OFFSET__") - 1) == 0) {
				/* substitute __COMPILER_HALT_OFFSET__ constant */
				zend_execute_data *orig_execute_data = EG(current_execute_data);
				zend_execute_data fake_execute_data;
				zval *offset;

				memset(&fake_execute_data, 0, sizeof(zend_execute_data));
				fake_execute_data.func = (zend_function*)op_array;
				EG(current_execute_data) = &fake_execute_data;
				if ((offset = zend_get_constant_str("__COMPILER_HALT_OFFSET__", sizeof("__COMPILER_HALT_OFFSET__") - 1 TSRMLS_CC)) != NULL) {
					zend_uint tv = ZEND_RESULT(opline).var;

					literal_dtor(&ZEND_OP2_LITERAL(opline));
					MAKE_NOP(opline);
					replace_tmp_by_const(op_array, opline, tv, offset TSRMLS_CC);
				}
				EG(current_execute_data) = orig_execute_data;
				break;
			}

			if (ZEND_OP1_TYPE(opline) == IS_UNUSED &&
				ZEND_OP2_TYPE(opline) == IS_CONST &&
				Z_TYPE(ZEND_OP2_LITERAL(opline)) == IS_STRING) {
				/* substitute persistent constants */
				zend_uint tv = ZEND_RESULT(opline).var;
				zval c;

				if (!zend_get_persistent_constant(Z_STR(ZEND_OP2_LITERAL(opline)), &c, 1 TSRMLS_CC)) {
					if (!ctx->constants || !zend_optimizer_get_collected_constant(ctx->constants, &ZEND_OP2_LITERAL(opline), &c)) {
						break;
					}
				}
				literal_dtor(&ZEND_OP2_LITERAL(opline));
				MAKE_NOP(opline);
				replace_tmp_by_const(op_array, opline, tv, &c TSRMLS_CC);
			}

#if ZEND_EXTENSION_API_NO > PHP_5_3_X_API_NO
			/* class constant */
			if (ZEND_OP1_TYPE(opline) != IS_UNUSED &&
			    ZEND_OP2_TYPE(opline) == IS_CONST &&
				Z_TYPE(ZEND_OP2_LITERAL(opline)) == IS_STRING) {

				zend_class_entry *ce = NULL;

				if (ZEND_OP1_TYPE(opline) == IS_CONST &&
			        Z_TYPE(ZEND_OP1_LITERAL(opline)) == IS_STRING) {
					/* for A::B */
					if (op_array->scope && 
						!strncasecmp(Z_STRVAL(ZEND_OP1_LITERAL(opline)),
						op_array->scope->name->val, Z_STRLEN(ZEND_OP1_LITERAL(opline)) + 1)) {
						ce = op_array->scope;
					} else { 
						if ((ce = zend_hash_find_ptr(EG(class_table), 
								Z_STR(op_array->literals[opline->op1.constant + 1]))) == NULL ||
								(ce->type == ZEND_INTERNAL_CLASS &&
								 ce->info.internal.module->type != MODULE_PERSISTENT) ||
								(ce->type == ZEND_USER_CLASS &&
								 ZEND_CE_FILENAME(ce) != op_array->filename)) {
							break;
						}
					}
				} else if (op_array->scope &&
					ZEND_OP1_TYPE(opline) == IS_VAR &&
					(opline - 1)->opcode == ZEND_FETCH_CLASS && 
					(ZEND_OP1_TYPE(opline - 1) == IS_UNUSED &&
					((opline - 1)->extended_value & ~ZEND_FETCH_CLASS_NO_AUTOLOAD) == ZEND_FETCH_CLASS_SELF) &&
					ZEND_RESULT((opline - 1)).var == ZEND_OP1(opline).var) {
					/* for self::B */
					ce = op_array->scope;
				}

				if (ce) {
					zend_uint tv = ZEND_RESULT(opline).var;
					zval *c, t;

					if ((c = zend_hash_find(&ce->constants_table,
							Z_STR(ZEND_OP2_LITERAL(opline)))) != NULL) {
						ZVAL_DEREF(c);
						if (ZEND_IS_CONSTANT_TYPE(Z_TYPE_P(c))) { 
							if (!zend_get_persistent_constant(Z_STR_P(c), &t, 1 TSRMLS_CC) ||
							    ZEND_IS_CONSTANT_TYPE(Z_TYPE(t))) {
								break;
							}
						} else {
							ZVAL_COPY_VALUE(&t, c);
							zval_copy_ctor(&t);
						}

						if (ZEND_OP1_TYPE(opline) == IS_CONST) {
							literal_dtor(&ZEND_OP1_LITERAL(opline));
						} else {
							MAKE_NOP((opline - 1));
						}
						literal_dtor(&ZEND_OP2_LITERAL(opline));
						MAKE_NOP(opline);
						replace_tmp_by_const(op_array, opline, tv, &t TSRMLS_CC);
					}
				}
			}
#endif
			break;

		case ZEND_INIT_FCALL:
			/* define("name", scalar); */
			if (collect_constants &&
			    ZEND_OP2_TYPE(opline) == IS_CONST &&
			    Z_TYPE(ZEND_OP2_LITERAL(opline)) == IS_STRING &&
			    Z_STRLEN(ZEND_OP2_LITERAL(opline)) == sizeof("define")-1 &&
			    zend_binary_strcasecmp(Z_STRVAL(ZEND_OP2_LITERAL(opline)), Z_STRLEN(ZEND_OP2_LITERAL(opline)), "define", sizeof("define")-1) == 0) {
				
				if ((opline+1)->opcode == ZEND_SEND_VAL &&
				    ZEND_OP1_TYPE(opline+1) == IS_CONST &&
				    Z_TYPE(ZEND_OP1_LITERAL(opline+1)) == IS_STRING &&
				    (opline+2)->opcode == ZEND_SEND_VAL &&
				    ZEND_OP1_TYPE(opline+2) == IS_CONST &&
				    Z_TYPE(ZEND_OP1_LITERAL(opline+2)) <= IS_STRING &&
				    (opline+3)->opcode == ZEND_DO_FCALL) {

					zend_optimizer_collect_constant(ctx, &ZEND_OP1_LITERAL(opline+1), &ZEND_OP1_LITERAL(opline+2));
					break;
				}
			} else {
				/* don't colllect constants after any other function call */
				collect_constants = 0;
			}

			/* pre-evaluate constant functions:
			   defined(x)
			   constant(x)
			   function_exists(x)
			   is_callable(x)
			   extension_loaded(x)
			*/
			if ((opline + 1)->opcode == ZEND_SEND_VAL &&
			    (opline + 2)->opcode == ZEND_DO_FCALL &&
				ZEND_OP1_TYPE(opline + 1) == IS_CONST && Z_TYPE(ZEND_OP1_LITERAL(opline + 1)) == IS_STRING &&
				ZEND_OP2_TYPE(opline) == IS_CONST && Z_TYPE(ZEND_OP2_LITERAL(opline)) == IS_STRING) {
				if ((Z_STRLEN(ZEND_OP2_LITERAL(opline)) == sizeof("function_exists")-1 &&
					!memcmp(Z_STRVAL(ZEND_OP2_LITERAL(opline)),
						"function_exists", sizeof("function_exists")-1)) ||
					(Z_STRLEN(ZEND_OP2_LITERAL(opline)) == sizeof("is_callable")-1 &&
					!memcmp(Z_STRVAL(ZEND_OP2_LITERAL(opline)),
						"is_callable", sizeof("is_callable")))) {
					zend_internal_function *func;
					char *lc_name = zend_str_tolower_dup(
							Z_STRVAL(ZEND_OP1_LITERAL(opline + 1)), Z_STRLEN(ZEND_OP1_LITERAL(opline + 1)));
					
					if ((func = zend_hash_str_find_ptr(EG(function_table), lc_name, Z_STRLEN(ZEND_OP1_LITERAL(opline + 1)))) != NULL &&
							func->type == ZEND_INTERNAL_FUNCTION &&
							func->module->type == MODULE_PERSISTENT) {
						zval t;
						ZVAL_BOOL(&t, 1);
						if (replace_var_by_const(op_array, opline + 3, ZEND_RESULT(opline + 2).var, &t TSRMLS_CC)) {
							literal_dtor(&ZEND_OP2_LITERAL(opline));
							MAKE_NOP(opline);
							literal_dtor(&ZEND_OP1_LITERAL(opline + 1));
							MAKE_NOP(opline + 1);
							MAKE_NOP(opline + 2);
						}
					}
					efree(lc_name);
				} else if (Z_STRLEN(ZEND_OP2_LITERAL(opline)) == sizeof("extension_loaded")-1 &&
					!memcmp(Z_STRVAL(ZEND_OP2_LITERAL(opline)),
						"extension_loaded", sizeof("extension_loaded")-1)) {
					zval t;
					char *lc_name = zend_str_tolower_dup(
							Z_STRVAL(ZEND_OP1_LITERAL(opline + 1)), Z_STRLEN(ZEND_OP1_LITERAL(opline + 1)));
					zend_module_entry *m = zend_hash_str_find_ptr(&module_registry,
							lc_name, Z_STRLEN(ZEND_OP1_LITERAL(opline + 1)));

					efree(lc_name);
					if (!m) {
						if (!PG(enable_dl)) {
							break;
						} else {
							ZVAL_BOOL(&t, 0);
						}
					} else {
						if (m->type == MODULE_PERSISTENT) {
							ZVAL_BOOL(&t, 1);
						} else {
							break;
						}
					} 

					if (replace_var_by_const(op_array, opline + 3, ZEND_RESULT(opline + 2).var, &t TSRMLS_CC)) {
						literal_dtor(&ZEND_OP2_LITERAL(opline));
						MAKE_NOP(opline);
						literal_dtor(&ZEND_OP1_LITERAL(opline + 1));
						MAKE_NOP(opline + 1);
						MAKE_NOP(opline + 2);
					}
				} else if (Z_STRLEN(ZEND_OP2_LITERAL(opline)) == sizeof("defined")-1 &&
					!memcmp(Z_STRVAL(ZEND_OP2_LITERAL(opline)),
						"defined", sizeof("defined")-1)) {
					zval t;

					if (zend_get_persistent_constant(Z_STR(ZEND_OP1_LITERAL(opline + 1)), &t, 0 TSRMLS_CC)) {

						ZVAL_BOOL(&t, 1);
						if (replace_var_by_const(op_array, opline + 3, ZEND_RESULT(opline + 2).var, &t TSRMLS_CC)) {
							literal_dtor(&ZEND_OP2_LITERAL(opline));
							MAKE_NOP(opline);
							literal_dtor(&ZEND_OP1_LITERAL(opline + 1));
							MAKE_NOP(opline + 1);
							MAKE_NOP(opline + 2);
						}
					}
				} else if (Z_STRLEN(ZEND_OP2_LITERAL(opline)) == sizeof("constant")-1 &&
					!memcmp(Z_STRVAL(ZEND_OP2_LITERAL(opline)),
						"constant", sizeof("constant")-1)) {
					zval t;
					
					if (zend_get_persistent_constant(Z_STR(ZEND_OP1_LITERAL(opline + 1)), &t, 1 TSRMLS_CC)) {
						if (replace_var_by_const(op_array, opline + 3, ZEND_RESULT(opline + 2).var, &t TSRMLS_CC)) {
							literal_dtor(&ZEND_OP2_LITERAL(opline));
							MAKE_NOP(opline);
							literal_dtor(&ZEND_OP1_LITERAL(opline + 1));
							MAKE_NOP(opline + 1);
							MAKE_NOP(opline + 2);
						}
					}
				} else if ((CG(compiler_options) & ZEND_COMPILE_NO_BUILTIN_STRLEN) == 0 &&
					Z_STRLEN(ZEND_OP2_LITERAL(opline)) == sizeof("strlen")-1 &&
					!memcmp(Z_STRVAL(ZEND_OP2_LITERAL(opline)),
						"strlen", sizeof("strlen")-1)) {
					zval t;

					ZVAL_LONG(&t, Z_STRLEN(ZEND_OP1_LITERAL(opline + 1)));
					if (replace_var_by_const(op_array, opline + 3, ZEND_RESULT(opline + 2).var, &t TSRMLS_CC)) {
						literal_dtor(&ZEND_OP2_LITERAL(opline));
						MAKE_NOP(opline);
						literal_dtor(&ZEND_OP1_LITERAL(opline + 1));
						MAKE_NOP(opline + 1);
						MAKE_NOP(opline + 2);
					}
				}
			}			
			break;
		case ZEND_STRLEN:
			if (ZEND_OP1_TYPE(opline) == IS_CONST &&
			    Z_TYPE(ZEND_OP1_LITERAL(opline)) == IS_STRING) {
				zval t;

				ZVAL_LONG(&t, Z_STRLEN(ZEND_OP1_LITERAL(opline)));
				replace_tmp_by_const(op_array, opline + 1, ZEND_RESULT(opline).var, &t TSRMLS_CC);
				literal_dtor(&ZEND_OP1_LITERAL(opline));
				MAKE_NOP(opline);
			}
			break;
#if ZEND_EXTENSION_API_NO > PHP_5_2_X_API_NO
		case ZEND_DECLARE_CONST:
			if (collect_constants &&
			    Z_TYPE(ZEND_OP1_LITERAL(opline)) == IS_STRING &&
			    Z_TYPE(ZEND_OP2_LITERAL(opline)) <= IS_STRING) {
				zend_optimizer_collect_constant(ctx, &ZEND_OP1_LITERAL(opline), &ZEND_OP2_LITERAL(opline));
			}
			break;
#endif

		case ZEND_RETURN:
#if ZEND_EXTENSION_API_NO > PHP_5_3_X_API_NO
		case ZEND_RETURN_BY_REF:
#endif
#if ZEND_EXTENSION_API_NO > PHP_5_4_X_API_NO
		case ZEND_GENERATOR_RETURN:
#endif
		case ZEND_EXIT:
		case ZEND_THROW:
		case ZEND_CATCH:
		case ZEND_BRK:
		case ZEND_CONT:
#if ZEND_EXTENSION_API_NO >= PHP_5_3_X_API_NO
		case ZEND_GOTO:
#endif
#if ZEND_EXTENSION_API_NO > PHP_5_4_X_API_NO
		case ZEND_FAST_CALL:
		case ZEND_FAST_RET:
#endif
		case ZEND_JMP:
		case ZEND_JMPZNZ:
		case ZEND_JMPZ:
		case ZEND_JMPNZ:
		case ZEND_JMPZ_EX:
		case ZEND_JMPNZ_EX:
		case ZEND_FE_RESET:
		case ZEND_FE_FETCH:
		case ZEND_NEW:
		case ZEND_DO_FCALL:
#if ZEND_EXTENSION_API_NO >= PHP_5_3_X_API_NO
		case ZEND_JMP_SET:
#endif
#if ZEND_EXTENSION_API_NO > PHP_5_3_X_API_NO
		case ZEND_JMP_SET_VAR:
#endif
			collect_constants = 0;
			break;
#if ZEND_EXTENSION_API_NO >= PHP_5_5_X_API_NO
		case ZEND_FETCH_R:
		case ZEND_FETCH_W:
		case ZEND_FETCH_RW:
		case ZEND_FETCH_FUNC_ARG:
		case ZEND_FETCH_IS:
		case ZEND_FETCH_UNSET:
			if (opline != op_array->opcodes &&
			    (opline-1)->opcode == ZEND_BEGIN_SILENCE &&
			    (opline->extended_value & ZEND_FETCH_TYPE_MASK) == ZEND_FETCH_LOCAL &&
				opline->op1_type == IS_CONST &&
			    opline->op2_type == IS_UNUSED &&
			    Z_TYPE(ZEND_OP1_LITERAL(opline)) == IS_STRING &&
			    (Z_STRLEN(ZEND_OP1_LITERAL(opline)) != sizeof("this")-1 ||
			     memcmp(Z_STRVAL(ZEND_OP1_LITERAL(opline)), "this", sizeof("this") - 1) != 0)) {

			    int var = opline->result.var;
			    int level = 0;
				zend_op *op = opline + 1;
				zend_op *use = NULL;

				while (op < end) {
					if (op->opcode == ZEND_BEGIN_SILENCE) {
						level++;
					} else if (op->opcode == ZEND_END_SILENCE) {
						if (level == 0) {
							break;
						} else {
							level--;
						}
					}
					if (op->op1_type == IS_VAR && op->op1.var == var) {
						if (use) {
							/* used more than once */
							use = NULL;
							break;
						}
						use = op;
					} else if (op->op2_type == IS_VAR && op->op2.var == var) {
						if (use) {
							/* used more than once */
							use = NULL;
							break;
						}
						use = op;
					}
					op++;
				}
				if (use) {
					if (use->op1_type == IS_VAR && use->op1.var == var) {
						use->op1_type = IS_CV;
						use->op1.var = zend_optimizer_lookup_cv(op_array,
							Z_STR(ZEND_OP1_LITERAL(opline)));
						MAKE_NOP(opline);
					} else if (use->op2_type == IS_VAR && use->op2.var == var) {
						use->op2_type = IS_CV;
						use->op2.var = zend_optimizer_lookup_cv(op_array,
							Z_STR(ZEND_OP1_LITERAL(opline)));
						MAKE_NOP(opline);
					}
				}
			}
			break;
#endif
		}
		opline++;
		i++;
	}
}