Module Name: src
Committed By: rillig
Date: Fri Jun 24 20:16:21 UTC 2022
Modified Files:
src/tests/usr.bin/xlint/lint1: msg_247.c
src/usr.bin/xlint/lint1: tree.c
Log Message:
lint: do not warn about pointer cast between sockaddr variants
To generate a diff of this commit:
cvs rdiff -u -r1.21 -r1.22 src/tests/usr.bin/xlint/lint1/msg_247.c
cvs rdiff -u -r1.460 -r1.461 src/usr.bin/xlint/lint1/tree.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/tests/usr.bin/xlint/lint1/msg_247.c
diff -u src/tests/usr.bin/xlint/lint1/msg_247.c:1.21 src/tests/usr.bin/xlint/lint1/msg_247.c:1.22
--- src/tests/usr.bin/xlint/lint1/msg_247.c:1.21 Fri Jun 24 20:02:58 2022
+++ src/tests/usr.bin/xlint/lint1/msg_247.c Fri Jun 24 20:16:21 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: msg_247.c,v 1.21 2022/06/24 20:02:58 rillig Exp $ */
+/* $NetBSD: msg_247.c,v 1.22 2022/06/24 20:16:21 rillig Exp $ */
# 3 "msg_247.c"
// Test for message: pointer cast from '%s' to '%s' may be troublesome [247]
@@ -14,13 +14,14 @@ struct Other {
int id;
};
-void
+PDisplay
example(struct Other *arg)
{
- PDisplay display;
-
/*
- * XXX: The target type is reported as 'struct <unnamed>'. In cases
+ * Before tree.c 1.461 from 2022-06-24, lint warned about the cast
+ * between the structs.
+ *
+ * XXX: The target type was reported as 'struct <unnamed>'. In cases
* like these, it would be helpful to print at least the type name
* of the pointer. This type name though is discarded immediately
* in the grammar rule 'typespec: T_TYPENAME'.
@@ -28,8 +29,7 @@ example(struct Other *arg)
* with no hint at all that there is a typedef for a pointer to the
* struct.
*/
- /* expect+1: warning: pointer cast from 'pointer to struct Other' to 'pointer to struct <unnamed>' may be troublesome [247] */
- display = (PDisplay)arg;
+ return (PDisplay)arg;
}
/*
@@ -249,21 +249,26 @@ struct sockaddr_in6 {
uint32_t sin6_scope_id;
};
+/*
+ * Before tree.c 1.461 from 2022-06-24, lint warned about the cast between the
+ * sockaddr variants. Since then, lint allows casts between pointers to
+ * structs if the initial members have compatible types and either of the
+ * struct types continues with a byte array.
+ */
void *
cast_between_sockaddr_variants(void *ptr)
{
- /* expect+1: warning: pointer cast from 'pointer to struct sockaddr' to 'pointer to struct sockaddr_in' may be troublesome [247] */
void *t1 = (struct sockaddr_in *)(struct sockaddr *)ptr;
-
- /* expect+1: warning: pointer cast from 'pointer to struct sockaddr_in' to 'pointer to struct sockaddr' may be troublesome [247] */
void *t2 = (struct sockaddr *)(struct sockaddr_in *)t1;
-
- /* expect+1: warning: pointer cast from 'pointer to struct sockaddr' to 'pointer to struct sockaddr_in6' may be troublesome [247] */
void *t3 = (struct sockaddr_in6 *)(struct sockaddr *)t2;
-
- /* expect+1: warning: pointer cast from 'pointer to struct sockaddr_in6' to 'pointer to struct sockaddr' may be troublesome [247] */
void *t4 = (struct sockaddr *)(struct sockaddr_in6 *)t3;
- return t4;
+ /* expect+1: warning: pointer cast from 'pointer to struct sockaddr_in6' to 'pointer to struct sockaddr_in' may be troublesome [247] */
+ void *t5 = (struct sockaddr_in *)(struct sockaddr_in6 *)t4;
+
+ /* expect+1: warning: pointer cast from 'pointer to struct sockaddr_in' to 'pointer to struct sockaddr_in6' may be troublesome [247] */
+ void *t6 = (struct sockaddr_in6 *)(struct sockaddr_in *)t5;
+
+ return t6;
}
Index: src/usr.bin/xlint/lint1/tree.c
diff -u src/usr.bin/xlint/lint1/tree.c:1.460 src/usr.bin/xlint/lint1/tree.c:1.461
--- src/usr.bin/xlint/lint1/tree.c:1.460 Fri Jun 24 19:27:43 2022
+++ src/usr.bin/xlint/lint1/tree.c Fri Jun 24 20:16:21 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: tree.c,v 1.460 2022/06/24 19:27:43 rillig Exp $ */
+/* $NetBSD: tree.c,v 1.461 2022/06/24 20:16:21 rillig Exp $ */
/*
* Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
#include <sys/cdefs.h>
#if defined(__RCSID)
-__RCSID("$NetBSD: tree.c,v 1.460 2022/06/24 19:27:43 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.461 2022/06/24 20:16:21 rillig Exp $");
#endif
#include <float.h>
@@ -2491,6 +2491,14 @@ check_pointer_integer_conversion(op_t op
}
static bool
+is_byte_array(const type_t *tp)
+{
+
+ return tp->t_tspec == ARRAY &&
+ (tp->t_subt->t_tspec == CHAR || tp->t_subt->t_tspec == UCHAR);
+}
+
+static bool
should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst,
const type_t *ostp, tspec_t ost)
{
@@ -2512,6 +2520,21 @@ should_warn_about_pointer_cast(const typ
if (ost == CHAR || ost == UCHAR)
return false; /* for the sake of traditional C code */
+ /* Allow cast between pointers to sockaddr variants. */
+ if (nst == STRUCT && ost == STRUCT) {
+ const sym_t *nmem = nstp->t_str->sou_first_member;
+ const sym_t *omem = ostp->t_str->sou_first_member;
+ while (nmem != NULL && omem != NULL &&
+ eqtype(nmem->s_type, omem->s_type, true, false, NULL))
+ nmem = nmem->s_next, omem = omem->s_next;
+ if (nmem != NULL && is_byte_array(nmem->s_type))
+ return false;
+ if (omem != NULL && is_byte_array(omem->s_type))
+ return false;
+ if (nmem == NULL && omem == NULL)
+ return false;
+ }
+
if (is_struct_or_union(nst) && nstp->t_str != ostp->t_str)
return true;
