From: Eric Botcazou <ebotcazou@adacore.com>
Date: Fri, 21 May 2021 08:40:41 +0000 (+0200)
Subject: Fix segfault at run time on strict-alignment platforms
X-Git-Tag: releases/gcc-11.2.0~350
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a9591c33e91b7cb1e544b4efb5987a93143a2a07;p=thirdparty%2Fgcc.git

Fix segfault at run time on strict-alignment platforms

This fixes a regression present on the mainline and 11 branch by
restricting the problematic change dealing with bitfields whose
nomimal subtype is self-referential to the cases where the size
is really lower.

gcc/ada/
	* gcc-interface/trans.c (Call_to_gnu): Restrict previous change
	to bitfields whose size is not equal to the type size.
	(gnat_to_gnu): Likewise.
---

diff --git a/gcc/ada/gcc-interface/trans.c b/gcc/ada/gcc-interface/trans.c
index 8d63d03079f9..d4435eab10ae 100644
--- a/gcc/ada/gcc-interface/trans.c
+++ b/gcc/ada/gcc-interface/trans.c
@@ -4553,6 +4553,8 @@ Call_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p, tree gnu_target,
 	  || (gnu_target
 	      && TREE_CODE (gnu_target) == COMPONENT_REF
 	      && DECL_BIT_FIELD (TREE_OPERAND (gnu_target, 1))
+	      && DECL_SIZE (TREE_OPERAND (gnu_target, 1))
+		 != TYPE_SIZE (TREE_TYPE (gnu_target))
 	      && type_is_padding_self_referential (gnu_result_type))))
     {
       gnu_retval = create_temporary ("R", gnu_result_type);
@@ -8271,7 +8273,9 @@ gnat_to_gnu (Node_Id gnat_node)
 	 much data.  But do not remove it if it is already too small.  */
       if (type_is_padding_self_referential (TREE_TYPE (gnu_result))
 	  && !(TREE_CODE (gnu_result) == COMPONENT_REF
-	       && DECL_BIT_FIELD (TREE_OPERAND (gnu_result, 1))))
+	       && DECL_BIT_FIELD (TREE_OPERAND (gnu_result, 1))
+	       && DECL_SIZE (TREE_OPERAND (gnu_result, 1))
+		  != TYPE_SIZE (TREE_TYPE (gnu_result))))
 	gnu_result = convert (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (gnu_result))),
 			      gnu_result);
     }