[src/trunk]: src/usr.bin/xlint/lint1 lint: clean up packing of structs and un...

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

details:   https://anonhg.NetBSD.org/src/rev/e92cd2195cc0
branches:  trunk
changeset: 377186:e92cd2195cc0
user:      rillig <rillig%NetBSD.org@localhost>
date:      Fri Jun 30 14:39:23 2023 +0000

description:
lint: clean up packing of structs and unions

No functional change outside debug mode.

diffstat:

 usr.bin/xlint/lint1/debug.c |   9 +++++-
 usr.bin/xlint/lint1/decl.c  |  56 ++++++++++++++++++++------------------------
 2 files changed, 32 insertions(+), 33 deletions(-)

diffs (125 lines):

diff -r e8b7fd922107 -r e92cd2195cc0 usr.bin/xlint/lint1/debug.c
--- a/usr.bin/xlint/lint1/debug.c       Fri Jun 30 12:21:25 2023 +0000
+++ b/usr.bin/xlint/lint1/debug.c       Fri Jun 30 14:39:23 2023 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: debug.c,v 1.37 2023/06/29 22:52:44 rillig Exp $ */
+/* $NetBSD: debug.c,v 1.38 2023/06/30 14:39:23 rillig Exp $ */
 
 /*-
  * Copyright (c) 2021 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID)
-__RCSID("$NetBSD: debug.c,v 1.37 2023/06/29 22:52:44 rillig Exp $");
+__RCSID("$NetBSD: debug.c,v 1.38 2023/06/30 14:39:23 rillig Exp $");
 #endif
 
 #include <stdlib.h>
@@ -125,6 +125,11 @@ debug_type_details(const type_t *tp)
 
        if (is_struct_or_union(tp->t_tspec)) {
                debug_indent_inc();
+               debug_step("size %u bits, align %u bits, %s",
+                   tp->t_sou->sou_size_in_bits,
+                   (unsigned int)tp->t_sou->sou_align_in_bits,
+                   tp->t_sou->sou_incomplete ? "incomplete" : "complete");
+
                for (const sym_t *mem = tp->t_sou->sou_first_member;
                     mem != NULL; mem = mem->s_next) {
                        debug_sym("", mem, "\n");
diff -r e8b7fd922107 -r e92cd2195cc0 usr.bin/xlint/lint1/decl.c
--- a/usr.bin/xlint/lint1/decl.c        Fri Jun 30 12:21:25 2023 +0000
+++ b/usr.bin/xlint/lint1/decl.c        Fri Jun 30 14:39:23 2023 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: decl.c,v 1.324 2023/06/30 07:18:02 rillig Exp $ */
+/* $NetBSD: decl.c,v 1.325 2023/06/30 14:39:23 rillig Exp $ */
 
 /*
  * Copyright (c) 1996 Christopher G. Demetriou.  All Rights Reserved.
@@ -38,7 +38,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID)
-__RCSID("$NetBSD: decl.c,v 1.324 2023/06/30 07:18:02 rillig Exp $");
+__RCSID("$NetBSD: decl.c,v 1.325 2023/06/30 14:39:23 rillig Exp $");
 #endif
 
 #include <sys/param.h>
@@ -471,37 +471,31 @@ bit_field_width(sym_t **mem)
 }
 
 static void
-set_packed_size(type_t *tp)
+pack_struct_or_union(type_t *tp)
 {
-       struct_or_union *sp;
-       sym_t *mem;
-
-       switch (tp->t_tspec) {
-       case STRUCT:
-       case UNION:
-               sp = tp->t_sou;
-               sp->sou_size_in_bits = 0;
-               for (mem = sp->sou_first_member;
-                    mem != NULL; mem = mem->s_next) {
-                       unsigned int x;
-
-                       if (mem->s_type->t_bitfield) {
-                               sp->sou_size_in_bits += bit_field_width(&mem);
-                               if (mem == NULL)
-                                       break;
-                       }
-                       x = type_size_in_bits(mem->s_type);
-                       if (tp->t_tspec == STRUCT)
-                               sp->sou_size_in_bits += x;
-                       else if (x > sp->sou_size_in_bits)
-                               sp->sou_size_in_bits = x;
-               }
-               break;
-       default:
+
+       if (!is_struct_or_union(tp->t_tspec)) {
                /* attribute '%s' ignored for '%s' */
                warning(326, "packed", type_name(tp));
-               break;
+               return;
        }
+
+       unsigned int bits = 0;
+       for (sym_t *mem = tp->t_sou->sou_first_member;
+            mem != NULL; mem = mem->s_next) {
+               // TODO: Maybe update mem->u.s_member.sm_offset_in_bits.
+               if (mem->s_type->t_bitfield) {
+                       bits += bit_field_width(&mem);
+                       if (mem == NULL)
+                               break;
+               }
+               unsigned int mem_bits = type_size_in_bits(mem->s_type);
+               if (tp->t_tspec == STRUCT)
+                       bits += mem_bits;
+               else if (mem_bits > bits)
+                       bits = mem_bits;
+       }
+       tp->t_sou->sou_size_in_bits = bits;
 }
 
 void
@@ -510,7 +504,7 @@ dcs_add_packed(void)
        if (dcs->d_type == NULL)
                dcs->d_packed = true;
        else
-               set_packed_size(dcs->d_type);
+               pack_struct_or_union(dcs->d_type);
 }
 
 void
@@ -1792,7 +1786,7 @@ complete_struct_or_union(sym_t *first_me
        sp->sou_incomplete = false;
        sp->sou_first_member = first_member;
        if (tp->t_packed)
-               set_packed_size(tp);
+               pack_struct_or_union(tp);
        else
                sp->sou_size_in_bits = dcs->d_offset_in_bits;