[src/trunk]: src/usr.bin/xlint/lint1 lint: remove over-engineered doubly-link...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5fa94aadd3d9
branches:  trunk
changeset: 953949:5fa94aadd3d9
user:      rillig <rillig%NetBSD.org@localhost>
date:      Thu Mar 25 20:38:16 2021 +0000

description:
lint: remove over-engineered doubly-linked circular list

The designation only needs to be navigated from head to tail, not the
other way round.

No functional change.

diffstat:

 usr.bin/xlint/lint1/init.c |  43 +++++++++++++++++++------------------------
 1 files changed, 19 insertions(+), 24 deletions(-)

diffs (90 lines):

diff -r 5125da1fed8c -r 5fa94aadd3d9 usr.bin/xlint/lint1/init.c
--- a/usr.bin/xlint/lint1/init.c        Thu Mar 25 20:11:18 2021 +0000
+++ b/usr.bin/xlint/lint1/init.c        Thu Mar 25 20:38:16 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: init.c,v 1.126 2021/03/25 20:11:18 rillig Exp $        */
+/*     $NetBSD: init.c,v 1.127 2021/03/25 20:38:16 rillig Exp $        */
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID) && !defined(lint)
-__RCSID("$NetBSD: init.c,v 1.126 2021/03/25 20:11:18 rillig Exp $");
+__RCSID("$NetBSD: init.c,v 1.127 2021/03/25 20:38:16 rillig Exp $");
 #endif
 
 #include <stdlib.h>
@@ -229,7 +229,6 @@
  */
 typedef struct namlist {
        const char *n_name;
-       struct namlist *n_prev;
        struct namlist *n_next;
 } namlist_t;
 
@@ -253,6 +252,7 @@
         * expression.
         */
        namlist_t *designation;
+       namlist_t *designation_tail;
 
        struct initialization *next;
 };
@@ -475,23 +475,18 @@
 void
 designator_push_name(sbuf_t *sb)
 {
-       namlist_t *designation = *current_designation_mod();
+       const namlist_t *designation = current_designation();
+
        namlist_t *nam = xcalloc(1, sizeof (namlist_t));
        nam->n_name = sb->sb_name;
 
-       if (designation == NULL) {
-               /*
-                * XXX: Why is this a circular list?
-                * XXX: Why is this a doubly-linked list?
-                * A simple queue should suffice.
-                */
-               nam->n_prev = nam->n_next = nam;
-               *current_designation_mod() = nam;
+       /* TODO: remove direct access to 'init' */
+       if (designation != NULL) {
+               init->designation_tail->n_next = nam;
+               init->designation_tail = nam;
        } else {
-               designation->n_prev->n_next = nam;
-               nam->n_prev = designation->n_prev;
-               nam->n_next = designation;
-               designation->n_prev = nam;
+               init->designation = nam;
+               init->designation_tail = nam;
        }
 
        debug_designation();
@@ -527,15 +522,15 @@
 static void
 designator_shift_name(void)
 {
-       namlist_t *head = *current_designation_mod();
-
-       if (head->n_next == head) {
-               free(head);
-               *current_designation_mod() = NULL;
+       /* TODO: remove direct access to 'init' */
+       lint_assert(init != NULL);
+       if (init->designation == init->designation_tail) {
+               free(init->designation);
+               init->designation = NULL;
+               init->designation_tail = NULL;
        } else {
-               *current_designation_mod() = head->n_next;
-               head->n_prev->n_next = head->n_next;
-               head->n_next->n_prev = head->n_prev;
+               namlist_t *head = init->designation;
+               init->designation = init->designation->n_next;
                free(head);
        }