From: Gary Dismukes <dismukes@adacore.com>
Date: Fri, 5 Sep 2025 20:58:54 +0000 (+0000)
Subject: ada: Incorrect expansion of VADS Size attribute applied to an array type
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b0f15d09da63effeb92d3d59f39bfab3c664bcaf;p=thirdparty%2Fgcc.git

ada: Incorrect expansion of VADS Size attribute applied to an array type

The compiler fails, either with an Assert_Failure (for a compiler with
assertions enabled) or by producing a bad value, when processing a VADS_Size
attribute (or a Size attribute when pragma Use_VADS_Size is in force),
in the case where the prefix denotes a composite type or subtype whose
object size (Esise) is not known by the front end. The bug is due to
Eval_Attribute attempting to fold a VADS-related size attribute even
when Esize is not yet known for the type.

gcc/ada/ChangeLog:

	* sem_attr.adb (Eval_Attribute): In the case of a VADS-specific
	size attribute, only fold to the object size when the Esize field
	is known.
---

diff --git a/gcc/ada/sem_attr.adb b/gcc/ada/sem_attr.adb
index e08dc42d903..bde4d40dcb5 100644
--- a/gcc/ada/sem_attr.adb
+++ b/gcc/ada/sem_attr.adb
@@ -10493,10 +10493,10 @@ package body Sem_Attr is
                         Fold_Uint (N, Expr_Value (Expression (S)), Static);
 
                      --  If no size is specified, then we simply use the object
-                     --  size in the VADS_Size case (e.g. Natural'Size is equal
-                     --  to Integer'Size, not one less).
+                     --  size (when known) in the VADS_Size case (for example,
+                     --  Natural'Size is equal to Integer'Size, not one less).
 
-                     else
+                     elsif Known_Esize (P_TypeA) then
                         Fold_Uint (N, Esize (P_TypeA), Static);
                      end if;
                   end;