[RFC] Convert exit (and die) from language constructs to functions (php#13483)

RFC: https://wiki.php.net/rfc/exit-as-function

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

@@ -162,10 +162,6 @@ 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

@@ -302,7 +302,6 @@ 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. */
@@ -506,7 +505,6 @@ 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/die_string_cast_exception.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Printing AST of die "constant" via assert
+--INI--
+zend.assertions=1
+--FILE--
+<?php
+
+try {
+    assert(0 && die);
+} catch (Throwable $e) {
+    echo $e::class, ': ', $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECT--
+AssertionError: assert(0 && \exit())

Zend/tests/exit/ast_print_assert_die_const.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Printing AST of die function via assert
+--INI--
+zend.assertions=1
+--FILE--
+<?php
+
+try {
+    assert(0 && die());
+} catch (Throwable $e) {
+    echo $e::class, ': ', $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECT--
+AssertionError: assert(0 && \exit())

Zend/tests/exit/ast_print_assert_die_function.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Printing AST of exit "constant" via assert
+--INI--
+zend.assertions=1
+--FILE--
+<?php
+
+try {
+    assert(0 && exit);
+} catch (Throwable $e) {
+    echo $e::class, ': ', $e->getMessage(), PHP_EOL;
+}
+
+?>
+--EXPECT--
+AssertionError: assert(0 && \exit())