Module Name: src
Committed By: rillig
Date: Fri Jun 24 20:44:53 UTC 2022
Modified Files:
src/tests/usr.bin/xlint/lint1: msg_247.c
src/usr.bin/xlint/lint1: tree.c
Log Message:
lint: allow pointer cast between compatible structs
Lint already allowed pointer casts from 'struct counter' to 'struct
counter_impl'. Now it also allows the other direction.
To generate a diff of this commit:
cvs rdiff -u -r1.23 -r1.24 src/tests/usr.bin/xlint/lint1/msg_247.c
cvs rdiff -u -r1.461 -r1.462 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:1.23 src/tests/usr.bin/xlint/lint1/msg_247.c:1.24
--- src/tests/usr.bin/xlint/lint1/msg_247.c:1.23 Fri Jun 24 20:32:12 2022
+++ src/tests/usr.bin/xlint/lint1/msg_247.c Fri Jun 24 20:44:53 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: msg_247.c,v 1.23 2022/06/24 20:32:12 rillig Exp $ */
+/* $NetBSD: msg_247.c,v 1.24 2022/06/24 20:44:53 rillig Exp $ */
# 3 "msg_247.c"
// Test for message: pointer cast from '%s' to '%s' may be troublesome [247]
@@ -117,7 +117,7 @@ counter_new_cast(void)
struct counter_impl *impl = allocate();
impl->public_part.count = 12345;
impl->saved_count = 12346;
- /* expect+1: warning: pointer cast from 'pointer to struct counter_impl' to 'pointer to struct counter' may be troublesome [247] */
+ /* Before tree.c 1.462 from 2022-06-24, lint warned about this cast. */
return (struct counter *)impl;
}
@@ -296,9 +296,9 @@ typedef struct ctl_named_node_s {
} ctl_named_node_t;
void *
-cast_between_initial_struct(void *ptr)
+cast_between_first_member_struct(void *ptr)
{
- /* expect+1: warning: pointer cast from 'pointer to struct ctl_named_node_s' to 'pointer to struct ctl_node_s' may be troublesome [247] */
+ /* Before tree.c 1.462 from 2022-06-24, lint warned about this cast. */
void *t1 = (ctl_node_t *)(ctl_named_node_t *)ptr;
void *t2 = (ctl_named_node_t *)(ctl_node_t *)ptr;
Index: src/usr.bin/xlint/lint1/tree.c
diff -u src/usr.bin/xlint/lint1/tree.c:1.461 src/usr.bin/xlint/lint1/tree.c:1.462
--- src/usr.bin/xlint/lint1/tree.c:1.461 Fri Jun 24 20:16:21 2022
+++ src/usr.bin/xlint/lint1/tree.c Fri Jun 24 20:44:53 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: tree.c,v 1.461 2022/06/24 20:16:21 rillig Exp $ */
+/* $NetBSD: tree.c,v 1.462 2022/06/24 20:44:53 rillig Exp $ */
/*
* Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
#include <sys/cdefs.h>
#if defined(__RCSID)
-__RCSID("$NetBSD: tree.c,v 1.461 2022/06/24 20:16:21 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.462 2022/06/24 20:44:53 rillig Exp $");
#endif
#include <float.h>
@@ -2491,6 +2491,15 @@ check_pointer_integer_conversion(op_t op
}
static bool
+struct_starts_with(const type_t *struct_tp, const type_t *member_tp)
+{
+
+ return struct_tp->t_str->sou_first_member != NULL &&
+ eqtype(struct_tp->t_str->sou_first_member->s_type, member_tp,
+ true, false, NULL);
+}
+
+static bool
is_byte_array(const type_t *tp)
{
@@ -2502,14 +2511,10 @@ static bool
should_warn_about_pointer_cast(const type_t *nstp, tspec_t nst,
const type_t *ostp, tspec_t ost)
{
- /*
- * Casting a pointer to 'struct S' to a pointer to another struct that
- * has 'struct S' as its first member is ok, see msg_247.c, 'struct
- * counter'.
- */
+
if (nst == STRUCT && ost == STRUCT &&
- nstp->t_str->sou_first_member != NULL &&
- nstp->t_str->sou_first_member->s_type == ostp)
+ (struct_starts_with(nstp, ostp) ||
+ struct_starts_with(ostp, nstp)))
return false;
if (is_incomplete(nstp) || is_incomplete(ostp))
