Zend: make exit/die a function instead of a language construct

Author: Girgias

Zend/Optimizer/block_pass.c

@@ -868,7 +868,6 @@ static void zend_optimize_block(zend_basic_block *block, zend_op_array *op_array
 				break;
 
 			case ZEND_RETURN:
-			case ZEND_EXIT:
 				if (opline->op1_type == IS_TMP_VAR) {
 					src = VAR_SOURCE(opline->op1);
 					if (src && src->opcode == ZEND_QM_ASSIGN) {
@@ -1221,8 +1220,7 @@ static void zend_jmp_optimization(zend_basic_block *block, zend_op_array *op_arr
 				target = op_array->opcodes + target_block->start;
 				if ((target->opcode == ZEND_RETURN ||
 				            target->opcode == ZEND_RETURN_BY_REF ||
-				            target->opcode == ZEND_GENERATOR_RETURN ||
-				            target->opcode == ZEND_EXIT) &&
+				            target->opcode == ZEND_GENERATOR_RETURN) &&
 				           !(op_array->fn_flags & ZEND_ACC_HAS_FINALLY_BLOCK)) {
 					/* JMP L, L: RETURN to immediate RETURN */
 					*last_op = *target;

Zend/Optimizer/pass1.c

@@ -331,7 +331,6 @@ void zend_optimizer_pass1(zend_op_array *op_array, zend_optimizer_ctx *ctx)
 		case ZEND_RETURN:
 		case ZEND_RETURN_BY_REF:
 		case ZEND_GENERATOR_RETURN:
-		case ZEND_EXIT:
 		case ZEND_THROW:
 		case ZEND_MATCH_ERROR:
 		case ZEND_CATCH:

Zend/Optimizer/pass3.c

@@ -88,8 +88,7 @@ void zend_optimizer_pass3(zend_op_array *op_array, zend_optimizer_ctx *ctx)
 					MAKE_NOP(opline);
 				} else if ((target->opcode == ZEND_RETURN ||
 				            target->opcode == ZEND_RETURN_BY_REF ||
-				            target->opcode == ZEND_GENERATOR_RETURN ||
-				            target->opcode == ZEND_EXIT) &&
+				            target->opcode == ZEND_GENERATOR_RETURN) &&
 				           !(op_array->fn_flags & ZEND_ACC_HAS_FINALLY_BLOCK)) {
 					/* JMP L, L: RETURN to immediate RETURN */
 					*opline = *target;

Zend/Optimizer/zend_call_graph.c

@@ -161,10 +161,6 @@ ZEND_API void zend_analyze_calls(zend_arena **arena, zend_script *script, uint32
 					call_info->send_unpack = 1;
 				}
 				break;
-			case ZEND_EXIT:
-				/* In this case the DO_CALL opcode may have been dropped
-				 * and caller_call_opline will be NULL. */
-				break;
 		}
 		opline++;
 	}

Zend/Optimizer/zend_cfg.c

@@ -303,7 +303,6 @@ ZEND_API void zend_build_cfg(zend_arena **arena, const zend_op_array *op_array,
 				}
 				break;
 			case ZEND_MATCH_ERROR:
-			case ZEND_EXIT:
 			case ZEND_THROW:
 				/* Don't treat THROW as terminator if it's used in expression context,
 				 * as we may lose live ranges when eliminating unreachable code. */
@@ -507,7 +506,6 @@ ZEND_API void zend_build_cfg(zend_arena **arena, const zend_op_array *op_array,
 			case ZEND_RETURN:
 			case ZEND_RETURN_BY_REF:
 			case ZEND_GENERATOR_RETURN:
-			case ZEND_EXIT:
 			case ZEND_THROW:
 			case ZEND_MATCH_ERROR:
 			case ZEND_VERIFY_NEVER_TYPE:

Zend/tests/arginfo_zpp_mismatch.inc

@@ -6,6 +6,9 @@ function skipFunction($function): bool {
      || $function === 'readline'
      || $function === 'readline_read_history'
      || $function === 'readline_write_history'
+        /* terminates script */
+     || $function === 'exit'
+     || $function === 'die'
         /* intentionally violate invariants */
      || $function === 'zend_create_unterminated_string'
      || $function === 'zend_test_array_return'

Zend/tests/exit/define_die_constant.phpt

@@ -9,4 +9,4 @@ var_dump(die);
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting identifier in %s on line %d
+Fatal error: Cannot define constant with name die in %s on line %d

Zend/tests/exit/define_die_constant_namespace.phpt

@@ -11,4 +11,4 @@ var_dump(die);
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting identifier in %s on line %d
+Fatal error: Cannot define constant with name die in %s on line %d

Zend/tests/exit/define_die_function.phpt

@@ -7,4 +7,4 @@ function die() { }
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting "(" in %s on line %d
+Fatal error: Defining a custom die() function is not allowed, as the function has special semantics in %s on line %d

Zend/tests/exit/define_die_function_namespace.phpt

@@ -11,4 +11,4 @@ var_dump(die());
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting "(" in %s on line %d
+Fatal error: Defining a custom die() function is not allowed, as the function has special semantics in %s on line %d

Zend/tests/exit/define_exit_constant.phpt

@@ -9,4 +9,4 @@ var_dump(exit);
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting identifier in %s on line %d
+Fatal error: Cannot define constant with name exit in %s on line %d

Zend/tests/exit/define_exit_constant_namespace.phpt

@@ -11,4 +11,4 @@ var_dump(exit);
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting identifier in %s on line %d
+Fatal error: Cannot define constant with name exit in %s on line %d

Zend/tests/exit/define_exit_function.phpt

@@ -7,4 +7,4 @@ function exit() { }
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting "(" in %s on line %d
+Fatal error: Defining a custom exit() function is not allowed, as the function has special semantics in %s on line %d

Zend/tests/exit/define_exit_function_namespace.phpt

@@ -9,4 +9,4 @@ function exit() { }
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting "(" in %s on line %d
+Fatal error: Defining a custom exit() function is not allowed, as the function has special semantics in %s on line %d

Zend/tests/exit/define_goto_label_die.phpt

@@ -10,5 +10,7 @@ die:
 echo "After\n";
 
 ?>
---EXPECTF--
-Parse error: syntax error, unexpected token ":" in %s on line %d
+--EXPECT--
+Before
+In between
+After

Zend/tests/exit/define_goto_label_die_with_jump.phpt

@@ -10,5 +10,6 @@ die:
 echo "After\n";
 
 ?>
---EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting identifier in %s on line %d
+--EXPECT--
+Before
+After

Zend/tests/exit/define_goto_label_exit.phpt

@@ -10,5 +10,7 @@ exit:
 echo "After\n";
 
 ?>
---EXPECTF--
-Parse error: syntax error, unexpected token ":" in %s on line %d
+--EXPECT--
+Before
+In between
+After

Zend/tests/exit/define_goto_label_exit_with_jump.phpt

@@ -10,5 +10,6 @@ exit:
 echo "After\n";
 
 ?>
---EXPECTF--
-Parse error: syntax error, unexpected token "exit", expecting identifier in %s on line %d
+--EXPECT--
+Before
+After

Zend/tests/exit/die_string_cast_exception.phpt

@@ -3,11 +3,12 @@ Bug #79777: String cast exception during die should be handled gracefully
 --FILE--
 <?php
 
-die(new stdClass);
+try {
+    die(new stdClass);
+} catch (TypeError $e) {
+    echo $e->getMessage(), PHP_EOL;
+}
 
 ?>
---EXPECTF--
-Fatal error: Uncaught Error: Object of class stdClass could not be converted to string in %s:%d
-Stack trace:
-#0 {main}
-  thrown in %s on line %d
+--EXPECT--
+die(): Argument #1 ($code) must be of type string|int, stdClass given

Zend/tests/exit/disabling_die.phpt

@@ -9,3 +9,4 @@ die();
 
 ?>
 --EXPECT--
+Warning: Cannot disable function die() in Unknown on line 0

Zend/tests/exit/disabling_exit.phpt

@@ -9,3 +9,4 @@ exit();
 
 ?>
 --EXPECT--
+Warning: Cannot disable function exit() in Unknown on line 0

Zend/tests/exit/exit_as_function.phpt

@@ -19,5 +19,24 @@ foreach ($values as $value) {
 }
 
 ?>
---EXPECTF--
-Parse error: syntax error, unexpected token "...", expecting ")" in %s on line %d
+--EXPECT--
+string(4) "exit"
+string(3) "die"
+object(Closure)#1 (2) {
+  ["function"]=>
+  string(4) "exit"
+  ["parameter"]=>
+  array(1) {
+    ["$code"]=>
+    string(10) "<optional>"
+  }
+}
+object(Closure)#2 (2) {
+  ["function"]=>
+  string(3) "die"
+  ["parameter"]=>
+  array(1) {
+    ["$code"]=>
+    string(10) "<optional>"
+  }
+}

Zend/tests/exit/exit_values.phpt

@@ -80,15 +80,15 @@ const FILE_PATH = __DIR__ . '/exit_values.inc';
 Using NULL as value:
 Exit status is: 0
 Output is:
-
+Deprecated: exit(): Passing null to parameter #1 ($code) of type string|int is deprecated in %s on line %d
 Using false as value:
 Exit status is: 0
 Output is:
 
 Using true as value:
-Exit status is: 0
+Exit status is: 1
 Output is:
-1
+
 Using 0 as value:
 Exit status is: 0
 Output is:
@@ -102,45 +102,45 @@ Exit status is: 20
 Output is:
 
 Using 10.0 as value:
-Exit status is: 0
+Exit status is: 10
 Output is:
-10
+
 Using 15.5 as value:
-Exit status is: 0
+Exit status is: 15
 Output is:
-15.5
+Deprecated: Implicit conversion from float 15.5 to int loses precision in %s on line %d
 Using 'Hello world' as value:
 Exit status is: 0
 Output is:
 Hello world
 Using [] as value:
 Exit status is: 0
 Output is:
-Warning: Array to string conversion in %s on line 3Array
+TypeError: exit(): Argument #1 ($code) must be of type string|int, array given
 Using STDERR as value:
 Exit status is: 0
 Output is:
-Resource id #3
+TypeError: exit(): Argument #1 ($code) must be of type string|int, resource given
 Using new stdClass() as value:
 Exit status is: 0
 Output is:
-Error: Object of class stdClass could not be converted to string
+TypeError: exit(): Argument #1 ($code) must be of type string|int, stdClass given
 As a statement:
 Exit status is: 0
 Output is:
-Error: Object of class stdClass could not be converted to string
+TypeError: exit(): Argument #1 ($code) must be of type string|int, stdClass given
 Using NULL as value:
 Exit status is: 0
 Output is:
-
+Deprecated: die(): Passing null to parameter #1 ($code) of type string|int is deprecated in %s on line %d
 Using false as value:
 Exit status is: 0
 Output is:
 
 Using true as value:
-Exit status is: 0
+Exit status is: 1
 Output is:
-1
+
 Using 0 as value:
 Exit status is: 0
 Output is:
@@ -154,30 +154,30 @@ Exit status is: 20
 Output is:
 
 Using 10.0 as value:
-Exit status is: 0
+Exit status is: 10
 Output is:
-10
+
 Using 15.5 as value:
-Exit status is: 0
+Exit status is: 15
 Output is:
-15.5
+Deprecated: Implicit conversion from float 15.5 to int loses precision in %s on line %d
 Using 'Hello world' as value:
 Exit status is: 0
 Output is:
 Hello world
 Using [] as value:
 Exit status is: 0
 Output is:
-Warning: Array to string conversion in %s on line 3Array
+TypeError: die(): Argument #1 ($code) must be of type string|int, array given
 Using STDERR as value:
 Exit status is: 0
 Output is:
-Resource id #3
+TypeError: die(): Argument #1 ($code) must be of type string|int, resource given
 Using new stdClass() as value:
 Exit status is: 0
 Output is:
-Error: Object of class stdClass could not be converted to string
+TypeError: die(): Argument #1 ($code) must be of type string|int, stdClass given
 As a statement:
 Exit status is: 0
 Output is:
-Error: Object of class stdClass could not be converted to string
+TypeError: die(): Argument #1 ($code) must be of type string|int, stdClass given

Zend/zend_API.c

@@ -3541,6 +3541,13 @@ ZEND_API zend_result zend_set_hash_symbol(zval *symbol, const char *name, size_t
 
 static void zend_disable_function(const char *function_name, size_t function_name_length)
 {
+	if (UNEXPECTED(
+		(function_name_length == strlen("exit") && !memcmp(function_name, "exit", strlen("exit")))
+		|| (function_name_length == strlen("die") && !memcmp(function_name, "die", strlen("die")))
+	)) {
+		zend_error(E_WARNING, "Cannot disable function %s()", function_name);
+		return;
+	}
 	zend_hash_str_del(CG(function_table), function_name, function_name_length);
 }
 

Zend/zend_builtin_functions.c

@@ -69,6 +69,29 @@ zend_result zend_startup_builtin_functions(void) /* {{{ */
 }
 /* }}} */
 
+ZEND_FUNCTION(exit)
+{
+	zend_string *str = NULL;
+	zend_long code = 0;
+
+	ZEND_PARSE_PARAMETERS_START(0, 1)
+		Z_PARAM_OPTIONAL
+		Z_PARAM_STR_OR_LONG(str, code)
+	ZEND_PARSE_PARAMETERS_END();
+
+	if (str) {
+		size_t len = ZSTR_LEN(str);
+		if (len != 0) {
+			zend_write(ZSTR_VAL(str), len);
+		}
+	} else {
+		EG(exit_status) = code;
+	}
+
+	ZEND_ASSERT(!EG(exception));
+	zend_throw_unwind_exit();
+}
+
 /* {{{ Get the version of the Zend Engine */
 ZEND_FUNCTION(zend_version)
 {

Zend/zend_builtin_functions.stub.php

@@ -7,6 +7,11 @@ class stdClass
 {
 }
 
+function exit(string|int $code = 0): never {}
+
+/** @alias exit */
+function die(string|int $code = 0): never {}
+
 /** @refcount 1 */
 function zend_version(): string {}