[PATCH] avoid error_mark_node in -Wsizeof-pointer-memaccess (PR 88065)

[Martin Sebor]

-Wsizeof-pointer-memaccess fails with an ICE when one of
the arguments is ill-formed (error_mark_node).  To avoid
the error the attached patch has the function bail in this
case.

Martin

PR c/88065 - ICE in -Wsizeof-pointer-memaccess on an invalid strncpy

gcc/c-family/ChangeLog:

	PR c/88065
	* c-warn.c (sizeof_pointer_memaccess_warning): Bail if source
	or destination is an error.

gcc/testsuite/ChangeLog:

	PR c/88065
	* gcc.dg/Wsizeof-pointer-memaccess2.c: New test.

Index: gcc/c-family/c-warn.c
===================================================================
--- gcc/c-family/c-warn.c	(revision 266240)
+++ gcc/c-family/c-warn.c	(working copy)
@@ -784,7 +784,10 @@ sizeof_pointer_memaccess_warning (location_t *size
   if (idx >= 3)
     return;
 
-  if (sizeof_arg[idx] == NULL || sizeof_arg[idx] == error_mark_node)
+  if (src == error_mark_node
+      || dest == error_mark_node
+      || sizeof_arg[idx] == NULL
+      || sizeof_arg[idx] == error_mark_node)
     return;
 
   type = TYPE_P (sizeof_arg[idx])
Index: gcc/testsuite/gcc.dg/Wsizeof-pointer-memaccess2.c
===================================================================
--- gcc/testsuite/gcc.dg/Wsizeof-pointer-memaccess2.c	(nonexistent)
+++ gcc/testsuite/gcc.dg/Wsizeof-pointer-memaccess2.c	(working copy)
@@ -0,0 +1,24 @@
+/* PR c/88065 - ICE in -Wsizeof-pointer-memaccess on an invalid strncpy
+   { dg-do compile }
+   { dg-options "-Wall" } */
+
+typedef __SIZE_TYPE__ size_t;
+
+char* strncpy (char*, const char*, size_t);
+
+struct S { char a[4], b[6]; };
+
+void test_invalid_dst (struct S *p)
+{
+  strncpy (q->a, p->b, sizeof p->b);    /* { dg-error ".q. undeclared" } */
+}
+
+void test_invalid_src (struct S *p)
+{
+  strncpy (p->a, q->b, sizeof p->b);    /* { dg-error ".q. undeclared" } */
+}
+
+void test_invalid_bound (struct S *p)
+{
+  strncpy (p->a, p->b, sizeof q->b);    /* { dg-error ".q. undeclared" } */
+}