From: Eric Botcazou <ebotcazou@adacore.come>
Date: Mon, 11 Nov 2024 10:16:26 +0000 (+0100)
Subject: ada: Do not use ATTR_ADDR_EXPR for 'Unrestricted_Access
X-Git-Tag: basepoints/gcc-16~3860
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ae7c0475f108f14cabcc1613df449670b1e9d1a2;p=thirdparty%2Fgcc.git

ada: Do not use ATTR_ADDR_EXPR for 'Unrestricted_Access

Unlike for 'Access or 'Unchecked_Access, the Attribute_to_gnu routine passes
ATTR_ADDR_EXPR to build_unary_op for 'Unrestricted_Access, which causes the
processing done in build_unary_op to flatten the reference, in particular to
remove all intermediate (view) conversions, which may be problematic for the
SUBSTITUTE_PLACEHOLDER_IN_EXPR machinery.

gcc/ada/ChangeLog:

	* gcc-interface/trans.cc (Attribute_to_gnu) <Attr_Access>: Do not
	pass ATTR_ADDR_EXPR to build_unary_op for 'Unrestricted_Access.
---

diff --git a/gcc/ada/gcc-interface/trans.cc b/gcc/ada/gcc-interface/trans.cc
index 5d971c1681d6..3aa41253d74c 100644
--- a/gcc/ada/gcc-interface/trans.cc
+++ b/gcc/ada/gcc-interface/trans.cc
@@ -1840,10 +1840,15 @@ Attribute_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p,
       gcc_assert (TREE_CODE (gnu_prefix) != TYPE_DECL);
 
       gnu_result_type = get_unpadded_type (Etype (gnat_node));
+
+      /* We used to pass ATTR_ADDR_EXPR for Attr_Unrestricted_Access too, but
+	 the processing done in build_unary_op for it flattens the reference,
+	 in particular removes all intermediate (view) conversions, which may
+	 cause SUBSTITUTE_PLACEHOLDER_IN_EXPR to fail to substitute in the
+	 bounds of a fat pointer returned for Attr_Unrestricted_Access.  */
       gnu_result
-	= build_unary_op (((attribute == Attr_Address
-			    || attribute == Attr_Unrestricted_Access)
-			   && !Must_Be_Byte_Aligned (gnat_node))
+	= build_unary_op (attribute == Attr_Address
+			  && !Must_Be_Byte_Aligned (gnat_node)
 			  ? ATTR_ADDR_EXPR : ADDR_EXPR,
 			  gnu_result_type, gnu_prefix);