From 0734a97ed8c728b6d9133e1433cccf79a823e5d4 Mon Sep 17 00:00:00 2001
From: Matthias Braun <matze@braunis.de>
Date: Fri, 18 Feb 2011 16:45:53 +0000
Subject: [PATCH] implement sizeof(func) and alignof(func) in gnu99 mode

[r28414]
---
 ast2firm.c | 12 +++++++++++-
 parser.c   | 28 ++++++++++++++++++++++------
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/ast2firm.c b/ast2firm.c
index 3464616..7b2881d 100644
--- a/ast2firm.c
+++ b/ast2firm.c
@@ -3040,6 +3040,11 @@ static ir_node *sizeof_to_firm(const typeprop_expression_t *expression)
 			&& expression->tp_expression != NULL) {
 		expression_to_firm(expression->tp_expression);
 	}
+	/* strange gnu extensions: sizeof(function) == 1 */
+	if (is_type_function(type)) {
+		ir_mode *mode = get_ir_mode_storage(type_size_t);
+		return new_Const(get_mode_one(mode));
+	}
 
 	return get_type_size_node(type);
 }
@@ -3079,7 +3084,12 @@ static ir_node *alignof_to_firm(const typeprop_expression_t *expression)
 	if (tp_expression != NULL) {
 		entity_t *entity = get_expression_entity(tp_expression);
 		if (entity != NULL) {
-			alignment = get_cparser_entity_alignment(entity);
+			if (entity->kind == ENTITY_FUNCTION) {
+				/* a gnu-extension */
+				alignment = 1;
+			} else {
+				alignment = get_cparser_entity_alignment(entity);
+			}
 		}
 	}
 
diff --git a/parser.c b/parser.c
index 70a7dc5..cd2f037 100644
--- a/parser.c
+++ b/parser.c
@@ -7274,12 +7274,28 @@ typeprop_expression:
 
 	tp_expression->typeprop.type   = orig_type;
 	type_t const* const type       = skip_typeref(orig_type);
-	char   const* const wrong_type =
-		GNU_MODE && is_type_atomic(type, ATOMIC_TYPE_VOID) ? NULL                  :
-		is_type_incomplete(type)                           ? "incomplete"          :
-		type->kind == TYPE_FUNCTION                        ? "function designator" :
-		type->kind == TYPE_BITFIELD                        ? "bitfield"            :
-		NULL;
+	char   const*       wrong_type = NULL;
+	if (is_type_incomplete(type)) {
+		if (!is_type_atomic(type, ATOMIC_TYPE_VOID) || !GNU_MODE)
+			wrong_type = "incomplete";
+	} else if (type->kind == TYPE_FUNCTION) {
+		if (GNU_MODE) {
+			/* function types are allowed (and return 1) */
+			if (warning.other) {
+				char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
+				warningf(&tp_expression->base.source_position,
+				         "%s expression with function argument returns invalid result", what);
+			}
+		} else {
+			wrong_type = "function";
+		}
+	} else {
+		if (is_type_incomplete(type))
+			wrong_type = "incomplete";
+	}
+	if (type->kind == TYPE_BITFIELD)
+		wrong_type = "bitfield";
+
 	if (wrong_type != NULL) {
 		char const* const what = kind == EXPR_SIZEOF ? "sizeof" : "alignof";
 		errorf(&tp_expression->base.source_position,
-- 
2.20.1