[src/trunk]: src/usr.bin/xlint/lint1 lint: use vector instead of list for des...

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

details:   https://anonhg.NetBSD.org/src/rev/e4b679e953d5
branches:  trunk
changeset: 1027739:e4b679e953d5
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat Dec 18 11:25:15 2021 +0000

description:
lint: use vector instead of list for designation in initialization

This change is a prerequisite for fixing the current bugs in handling
initializations.  Part of the fix will be designation_pop, which is
costly for a singly linked list.

As a side benefit, memory management becomes simpler and needs fewer
malloc calls.

No functional change.

diffstat:

 usr.bin/xlint/lint1/init.c |  82 +++++++++++++++++----------------------------
 1 files changed, 32 insertions(+), 50 deletions(-)

diffs (177 lines):

diff -r d51f91de0e9f -r e4b679e953d5 usr.bin/xlint/lint1/init.c
--- a/usr.bin/xlint/lint1/init.c        Sat Dec 18 10:50:48 2021 +0000
+++ b/usr.bin/xlint/lint1/init.c        Sat Dec 18 11:25:15 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: init.c,v 1.217 2021/12/17 17:27:19 rillig Exp $        */
+/*     $NetBSD: init.c,v 1.218 2021/12/18 11:25:15 rillig Exp $        */
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -38,7 +38,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID) && !defined(lint)
-__RCSID("$NetBSD: init.c,v 1.217 2021/12/17 17:27:19 rillig Exp $");
+__RCSID("$NetBSD: init.c,v 1.218 2021/12/18 11:25:15 rillig Exp $");
 #endif
 
 #include <stdlib.h>
@@ -97,7 +97,6 @@
 struct designator {
        const char      *dr_name;       /* for struct and union */
        size_t          dr_subscript;   /* for array */
-       struct designator *dr_next;
 };
 
 /*
@@ -108,8 +107,9 @@
  * C99 6.7.8p6, 6.7.8p7
  */
 struct designation {
-       struct designator *dn_head;
-       struct designator *dn_tail;
+       struct designator *dn_items;
+       size_t dn_len;
+       size_t dn_cap;
 };
 
 /*
@@ -371,25 +371,6 @@
 }
 
 
-static struct designator *
-designator_new(const char *name, size_t subscript)
-{
-       struct designator *dr;
-
-       dr = xcalloc(1, sizeof(*dr));
-       dr->dr_name = name;
-       dr->dr_subscript = subscript;
-       return dr;
-}
-
-static void
-designator_free(struct designator *dr)
-{
-
-       free(dr);
-}
-
-
 static const type_t *
 designator_look_up(const struct designator *dr, const type_t *tp)
 {
@@ -427,14 +408,15 @@
 static void
 designation_debug(const struct designation *dn)
 {
-       const struct designator *dr;
+       size_t i;
 
-       if (dn->dn_head == NULL)
+       if (dn->dn_len == 0)
                return;
 
        debug_indent();
        debug_printf("designation: ");
-       for (dr = dn->dn_head; dr != NULL; dr = dr->dr_next) {
+       for (i = 0; i < dn->dn_len; i++) {
+               const struct designator *dr = dn->dn_items + i;
                if (dr->dr_name != NULL) {
                        debug_printf(".%s", dr->dr_name);
                        lint_assert(dr->dr_subscript == 0);
@@ -450,17 +432,16 @@
 static void
 designation_add(struct designation *dn, const char *name, size_t subscript)
 {
-       struct designator *dr;
-
-       dr = designator_new(name, subscript);
 
-       if (dn->dn_head != NULL) {
-               dn->dn_tail->dr_next = dr;
-               dn->dn_tail = dr;
-       } else {
-               dn->dn_head = dr;
-               dn->dn_tail = dr;
+       if (dn->dn_len == dn->dn_cap) {
+               dn->dn_cap += 4;
+               dn->dn_items = xrealloc(dn->dn_items,
+                   dn->dn_cap * sizeof(dn->dn_items[0]));
        }
+
+       dn->dn_items[dn->dn_len].dr_name = name;
+       dn->dn_items[dn->dn_len].dr_subscript = subscript;
+       dn->dn_len++;
 }
 
 /*
@@ -472,25 +453,25 @@
 static const type_t *
 designation_look_up(const struct designation *dn, const type_t *tp)
 {
-       const struct designator *dr;
+       size_t i;
 
-       for (dr = dn->dn_head; dr != NULL && tp != NULL; dr = dr->dr_next)
-               tp = designator_look_up(dr, tp);
+       for (i = 0; i < dn->dn_len && tp != NULL; i++)
+               tp = designator_look_up(dn->dn_items + i, tp);
        return tp;
 }
 
 static void
 designation_reset(struct designation *dn)
 {
-       struct designator *dr, *next;
+
+       dn->dn_len = 0;
+}
 
-       for (dr = dn->dn_head; dr != NULL; dr = next) {
-               next = dr->dr_next;
-               designator_free(dr);
-       }
+static void
+designation_free(struct designation *dn)
+{
 
-       dn->dn_head = NULL;
-       dn->dn_tail = NULL;
+       free(dn->dn_items);
 }
 
 
@@ -512,7 +493,7 @@
 brace_level_free(struct brace_level *bl)
 {
 
-       designation_reset(&bl->bl_designation);
+       designation_free(&bl->bl_designation);
        free(bl);
 }
 
@@ -542,7 +523,7 @@
 brace_level_sub_type(const struct brace_level *bl, bool is_string)
 {
 
-       if (bl->bl_designation.dn_head != NULL)
+       if (bl->bl_designation.dn_len > 0)
                return designation_look_up(&bl->bl_designation, bl->bl_type);
 
        switch (bl->bl_type->t_tspec) {
@@ -583,10 +564,11 @@
 static void
 brace_level_apply_designation(struct brace_level *bl)
 {
-       const struct designator *dr = bl->bl_designation.dn_head;
+       const struct designator *dr;
 
-       if (dr == NULL)
+       if (bl->bl_designation.dn_len == 0)
                return;
+       dr = &bl->bl_designation.dn_items[0];
 
        designation_debug(&bl->bl_designation);