Added default as an expression in argument lists.

Author: Bilge

Zend/zend_ast.h

@@ -74,6 +74,7 @@ enum _zend_ast_kind {
 	ZEND_AST_TYPE,
 	ZEND_AST_CONSTANT_CLASS,
 	ZEND_AST_CALLABLE_CONVERT,
+	ZEND_AST_DEFAULT,
 
 	/* 1 child node */
 	ZEND_AST_VAR = 1 << ZEND_AST_NUM_CHILDREN_SHIFT,

Zend/zend_compile.c

@@ -3778,6 +3778,8 @@ static uint32_t zend_compile_args(
 			arg_count++;
 		}
 
+		CG(arg_num) = arg_num;
+
 		/* Treat passing of $GLOBALS the same as passing a call.
 		 * This will error at runtime if the argument is by-ref. */
 		if (zend_is_call(arg) || is_globals_fetch(arg)) {
@@ -3896,6 +3898,12 @@ static uint32_t zend_compile_args(
 }
 /* }}} */
 
+static void zend_compile_default(znode *result, zend_ast *ast)
+{
+	zend_op *opline = zend_emit_op_tmp(result, ZEND_FETCH_DEFAULT_ARG, NULL, NULL);
+	opline->op1.num = CG(arg_num);
+}
+
 ZEND_API uint8_t zend_get_call_op(const zend_op *init_op, zend_function *fbc) /* {{{ */
 {
 	if (fbc) {
@@ -11497,6 +11505,9 @@ static void zend_compile_expr_inner(znode *result, zend_ast *ast) /* {{{ */
 		case ZEND_AST_MATCH:
 			zend_compile_match(result, ast);
 			return;
+		case ZEND_AST_DEFAULT:
+			zend_compile_default(result, ast);
+			return;
 		default:
 			ZEND_ASSERT(0 /* not supported */);
 	}

Zend/zend_globals.h

@@ -154,6 +154,8 @@ struct _zend_compiler_globals {
 	uint32_t rtd_key_counter;
 
 	zend_stack short_circuiting_opnums;
+
+	uint32_t arg_num;
 #ifdef ZTS
 	uint32_t copied_functions_count;
 #endif

Zend/zend_language_parser.y

@@ -251,7 +251,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 %type <ast> group_use_declaration inline_use_declarations inline_use_declaration
 %type <ast> mixed_group_use_declaration use_declaration unprefixed_use_declaration
 %type <ast> unprefixed_use_declarations const_decl inner_statement
-%type <ast> expr optional_expr while_statement for_statement foreach_variable
+%type <ast> expr expr_with_default optional_expr while_statement for_statement foreach_variable
 %type <ast> foreach_statement declare_statement finally_statement unset_variable variable
 %type <ast> extends_from parameter optional_type_without_static argument global_var
 %type <ast> static_var class_statement trait_adaptation trait_precedence trait_alias
@@ -904,7 +904,7 @@ non_empty_argument_list:
 ;
 
 argument:
-		expr				{ $$ = $1; }
+		expr_with_default   { $$ = $1; }
 	|	identifier ':' expr
 			{ $$ = zend_ast_create(ZEND_AST_NAMED_ARG, $1, $3); }
 	|	T_ELLIPSIS expr	{ $$ = zend_ast_create(ZEND_AST_UNPACK, $2); }
@@ -1326,6 +1326,10 @@ expr:
 	|	match { $$ = $1; }
 ;
 
+expr_with_default:
+		expr		{ $$ = $1; }
+	|	T_DEFAULT   { $$ = zend_ast_create(ZEND_AST_DEFAULT); }
+;
 
 inline_function:
 		function returns_ref backup_doc_comment '(' parameter_list ')' lexical_vars return_type

Zend/zend_vm_def.h

@@ -9808,6 +9808,44 @@ ZEND_VM_HANDLER(209, ZEND_INIT_PARENT_PROPERTY_HOOK_CALL, CONST, UNUSED|NUM, NUM
 	ZEND_VM_NEXT_OPCODE();
 }
 
+ZEND_VM_HANDLER(210, ZEND_FETCH_DEFAULT_ARG, UNUSED, UNUSED)
+{
+	USE_OPLINE
+	SAVE_OPLINE();
+
+	zend_function *called_func = EX(call)->func;
+
+	zend_string *reflection_class_name = ZSTR_INIT_LITERAL("ReflectionParameter", 0);
+	zend_class_entry *reflection_class = zend_fetch_class(reflection_class_name, ZEND_FETCH_CLASS_DEFAULT);
+	zend_string_release(reflection_class_name);
+
+	/*
+	 * [0]: The function (string) or class method (array) to reflect parameters from.
+	 * [1]: A zero-based integer specifying the parameter position.
+	 */
+	zval constructor_params[2];
+	ZVAL_LONG(&constructor_params[1], opline->op1.num - 1);
+	if (called_func->common.scope == NULL) {
+		ZVAL_STR_COPY(&constructor_params[0], called_func->common.function_name);
+	} else {
+		zval arr;
+		array_init_size(&arr, 2);
+		add_next_index_string(&arr, called_func->common.scope->name->val);
+		add_next_index_string(&arr, called_func->common.function_name->val);
+		ZVAL_ARR(&constructor_params[0], Z_ARR(arr));
+	}
+
+	zval reflection_obj;
+	// TODO: Check result.
+	/*zend_result res =*/ object_init_with_constructor(&reflection_obj, reflection_class, 2, constructor_params, NULL);
+
+	zval default_value;
+	zend_call_method_with_0_params(Z_OBJ(reflection_obj), reflection_class, NULL, "getDefaultValue", &default_value);
+
+	ZVAL_COPY_VALUE(EX_VAR(opline->result.var), &default_value);
+	ZEND_VM_NEXT_OPCODE();
+}
+
 ZEND_VM_HOT_TYPE_SPEC_HANDLER(ZEND_JMP, (OP_JMP_ADDR(op, op->op1) > op), ZEND_JMP_FORWARD, JMP_ADDR, ANY)
 {
 	USE_OPLINE