[src/trunk]: src/usr.bin/xlint/lint1 lint: replace namlist with designation a...

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

details:   https://anonhg.NetBSD.org/src/rev/c06338506841
branches:  trunk
changeset: 953950:c06338506841
user:      rillig <rillig%NetBSD.org@localhost>
date:      Thu Mar 25 21:07:52 2021 +0000

description:
lint: replace namlist with designation and designator

This makes it possible to accurately model C99 initializers, including
their optional designators.  Previously, array subscripts had not been
modeled at all.

In the previous commit, debug_designation crashed immediately since I
had not run the code in debug mode even once.  The condition 'name !=
head' was a left-over from the old times where the designator was still
a circular list.

No functional change outside debug mode.

diffstat:

 usr.bin/xlint/lint1/init.c |  109 ++++++++++++++++++++++----------------------
 1 files changed, 54 insertions(+), 55 deletions(-)

diffs (255 lines):

diff -r 5fa94aadd3d9 -r c06338506841 usr.bin/xlint/lint1/init.c
--- a/usr.bin/xlint/lint1/init.c        Thu Mar 25 20:38:16 2021 +0000
+++ b/usr.bin/xlint/lint1/init.c        Thu Mar 25 21:07:52 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: init.c,v 1.127 2021/03/25 20:38:16 rillig Exp $        */
+/*     $NetBSD: init.c,v 1.128 2021/03/25 21:07:52 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 1.127 2021/03/25 20:38:16 rillig Exp $");
+__RCSID("$NetBSD: init.c,v 1.128 2021/03/25 21:07:52 rillig Exp $");
 #endif
 
 #include <stdlib.h>
@@ -215,22 +215,24 @@
 } initstack_element;
 
 /*
- * The names for a nested C99 initialization designator, in a circular list.
+ * Leads the path to the sub-object to initialize using the expression.
+ * Example designators are '.member' or '.member[123].member.member[1][1]'.
  *
- * Example:
- *     struct stat st = {
- *             .st_size = 123,
- *             .st_mtim.tv_sec = 45,
- *             .st_mtim.tv_nsec
- *     };
- *
- *     During initialization, this list first contains ["st_size"], then
- *     ["st_mtim", "tv_sec"], then ["st_mtim", "tv_nsec"].
+ * See also: C99 6.7.8 "Initialization"
  */
-typedef struct namlist {
-       const char *n_name;
-       struct namlist *n_next;
-} namlist_t;
+typedef struct designator {
+       const char *name;               /* for struct and union */
+       /* TODO: add 'subscript' for arrays */
+       struct designator *next;
+} designator;
+
+/*
+ * See also: C99 6.7.8 "Initialization"
+ */
+typedef struct {
+       designator *head;
+       designator *tail;
+} designation;
 
 struct initialization {
        /*
@@ -251,8 +253,7 @@
         * The C99 designator, if any, for the current initialization
         * expression.
         */
-       namlist_t *designation;
-       namlist_t *designation_tail;
+       designation designation;
 
        struct initialization *next;
 };
@@ -280,14 +281,14 @@
        return &init->initsym;
 }
 
-static namlist_t **
+static designation *
 current_designation_mod(void)
 {
        lint_assert(init != NULL);
        return &init->designation;
 }
 
-static const namlist_t *
+static designation
 current_designation(void)
 {
        return *current_designation_mod();
@@ -375,17 +376,14 @@
 static void
 debug_designation(void)
 {
-       const namlist_t *head = current_designation(), *name;
+       const designator *head = current_designation().head, *p;
        if (head == NULL)
                return;
 
        debug_indent();
        debug_printf("designation: ");
-       name = head;
-       do {
-               debug_printf(".%s", name->n_name);
-               name = name->n_next;
-       } while (name != head);
+       for (p = head; p != NULL; p = p->next)
+               debug_printf(".%s", p->name);
        debug_printf("\n");
 }
 
@@ -475,18 +473,17 @@
 void
 designator_push_name(sbuf_t *sb)
 {
-       const namlist_t *designation = current_designation();
+       designation *dd = current_designation_mod();
 
-       namlist_t *nam = xcalloc(1, sizeof (namlist_t));
-       nam->n_name = sb->sb_name;
+       designator *d = xcalloc(1, sizeof *d);
+       d->name = sb->sb_name;
 
-       /* TODO: remove direct access to 'init' */
-       if (designation != NULL) {
-               init->designation_tail->n_next = nam;
-               init->designation_tail = nam;
+       if (dd->head != NULL) {
+               dd->tail->next = d;
+               dd->tail = d;
        } else {
-               init->designation = nam;
-               init->designation_tail = nam;
+               dd->head = d;
+               dd->tail = d;
        }
 
        debug_designation();
@@ -524,13 +521,14 @@
 {
        /* 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;
+       lint_assert(init->designation.head != NULL);
+       if (init->designation.head == init->designation.tail) {
+               free(init->designation.head);
+               init->designation.head = NULL;
+               init->designation.tail = NULL;
        } else {
-               namlist_t *head = init->designation;
-               init->designation = init->designation->n_next;
+               designator *head = init->designation.head;
+               init->designation.head = init->designation.head->next;
                free(head);
        }
 
@@ -552,7 +550,7 @@
                return;
 
        /* TODO: merge into init_using_expr */
-       while (current_designation() != NULL)
+       while (current_designation().head != NULL)
                designator_shift_name();
 
        debug_enter();
@@ -585,7 +583,7 @@
         * related to initializing the named member.
         */
        debug_step("initializing named member '%s'",
-           current_designation()->n_name);
+           current_designation().head->name);
 
        if (istk->i_type->t_tspec != STRUCT &&
            istk->i_type->t_tspec != UNION) {
@@ -601,7 +599,7 @@
                if (m->s_bitfield && m->s_name == unnamed)
                        continue;
 
-               if (strcmp(m->s_name, current_designation()->n_name) == 0) {
+               if (strcmp(m->s_name, current_designation().head->name) == 0) {
                        debug_step("found matching member");
                        istk->i_subt = m->s_type;
                        /* XXX: why ++? */
@@ -613,7 +611,7 @@
        }
 
        /* undefined struct/union member: %s */
-       error(101, current_designation()->n_name);
+       error(101, current_designation().head->name);
 
        designator_shift_name();
        istk->i_seen_named_member = true;
@@ -666,7 +664,7 @@
        lint_assert(istk->i_remaining >= 0);
        debug_step("%d elements remaining", istk->i_remaining);
 
-       if (current_designation() != NULL)
+       if (current_designation().head != NULL)
                initstack_pop_item_named_member();
        else
                initstack_pop_item_unnamed();
@@ -806,12 +804,12 @@
                 * look_up_struct_next
                 * look_up_struct_designator
                 */
-               if (current_designation() != NULL) {
+               if (current_designation().head != NULL) {
                        /* XXX: this log entry looks unnecessarily verbose */
                        debug_step("have member '%s', want member '%s'",
-                           m->s_name, current_designation()->n_name);
-                       if (strcmp(m->s_name, current_designation()->n_name) ==
-                           0) {
+                           m->s_name, current_designation().head->name);
+                       if (strcmp(m->s_name,
+                           current_designation().head->name) == 0) {
                                cnt++;
                                break;
                        } else
@@ -823,7 +821,7 @@
                }
        }
 
-       if (current_designation() != NULL) {
+       if (current_designation().head != NULL) {
                if (m == NULL) {
                        debug_step("pop struct");
                        return true;
@@ -831,7 +829,8 @@
                istk->i_next_member = m;
                istk->i_subt = m->s_type;
                istk->i_seen_named_member = true;
-               debug_step("named member '%s'", current_designation()->n_name);
+               debug_step("named member '%s'",
+                   current_designation().head->name);
                designator_shift_name();
                cnt = istk->i_type->t_tspec == STRUCT ? 2 : 1;
        }
@@ -876,9 +875,9 @@
        lint_assert(istk->i_type != NULL);
        switch (istk->i_type->t_tspec) {
        case ARRAY:
-               if (current_designation() != NULL) {
+               if (current_designation().head != NULL) {
                        debug_step("pop array, named member '%s'%s",
-                           current_designation()->n_name,
+                           current_designation().head->name,
                            istk->i_brace ? ", needs closing brace" : "");
                        goto pop;
                }
@@ -896,7 +895,7 @@
                        goto pop;
                break;
        default:
-               if (current_designation() != NULL) {
+               if (current_designation().head != NULL) {
                        debug_step("pop scalar");
        pop:
                        /* TODO: extract this into end_initializer_level */