[src/trunk]: src/usr.bin/xlint/lint1 lint: do not use portable type sizes in ...

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

details:   https://anonhg.NetBSD.org/src/rev/0b53dad82bb2
branches:  trunk
changeset: 377355:0b53dad82bb2
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat Jul 08 15:26:25 2023 +0000

description:
lint: do not use portable type sizes in integer constraints

This reverts the change from tree.c 1.547 from 2023-07-03.  Back then, I
didn't know that the actual value from a type's 'portable size in bits'
was not supposed to be used.

diffstat:

 tests/usr.bin/xlint/lint1/msg_247_portable.c    |   3 ++-
 tests/usr.bin/xlint/lint1/platform_ilp32_long.c |  16 +++++++++-------
 usr.bin/xlint/lint1/tree.c                      |  13 ++++++-------
 3 files changed, 17 insertions(+), 15 deletions(-)

diffs (91 lines):

diff -r c54c3ea935a5 -r 0b53dad82bb2 tests/usr.bin/xlint/lint1/msg_247_portable.c
--- a/tests/usr.bin/xlint/lint1/msg_247_portable.c      Sat Jul 08 14:05:51 2023 +0000
+++ b/tests/usr.bin/xlint/lint1/msg_247_portable.c      Sat Jul 08 15:26:25 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: msg_247_portable.c,v 1.2 2023/07/05 11:42:14 rillig Exp $      */
+/*     $NetBSD: msg_247_portable.c,v 1.3 2023/07/08 15:26:25 rillig Exp $      */
 # 3 "msg_247_portable.c"
 
 // Test for message: pointer cast from '%s' to '%s' may be troublesome [247]
@@ -11,6 +11,7 @@
 //     msg_247_ilp32_ldbl64.c
 //     msg_247_lp64_ldbl128.c
 
+/* lint1-only-if: long */
 /* lint1-extra-flags: -c -p -X 351 */
 
 typedef double double_array[5];
diff -r c54c3ea935a5 -r 0b53dad82bb2 tests/usr.bin/xlint/lint1/platform_ilp32_long.c
--- a/tests/usr.bin/xlint/lint1/platform_ilp32_long.c   Sat Jul 08 14:05:51 2023 +0000
+++ b/tests/usr.bin/xlint/lint1/platform_ilp32_long.c   Sat Jul 08 15:26:25 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: platform_ilp32_long.c,v 1.3 2023/07/03 21:36:16 rillig Exp $   */
+/*     $NetBSD: platform_ilp32_long.c,v 1.4 2023/07/08 15:26:25 rillig Exp $   */
 # 3 "platform_ilp32_long.c"
 
 /*
@@ -22,15 +22,17 @@ void
 convert_between_int_and_long(void)
 {
        /*
-        * Even though 'long' and 'int' have the same size on this platform,
-        * the option '-p' enables additional portability checks that assume
-        * a 24-bit int and a 32-bit long type, to proactively detect loss of
-        * accuracy on potential other platforms.
+        * The '-p' option enables checks that apply independently of the
+        * current platform, assuming that 'long' is always wider than 'int'.
+        * This assumption, when applied on its own, leads to wrong warnings
+        * that a 32-bit 'long' may lose accuracy when converted to a 32-bit
+        * 'int'.
+        *
+        * To avoid these, take a look at the actually possible values of the
+        * right-hand side, and if they fit in the left-hand side, don't warn.
         */
-       /* expect+1: warning: conversion from 'long' to 'int' may lose accuracy [132] */
        s32 = sl32;
        sl32 = s32;
-       /* expect+1: warning: conversion from 'unsigned long' to 'unsigned int' may lose accuracy [132] */
        u32 = ul32;
        ul32 = u32;
 }
diff -r c54c3ea935a5 -r 0b53dad82bb2 usr.bin/xlint/lint1/tree.c
--- a/usr.bin/xlint/lint1/tree.c        Sat Jul 08 14:05:51 2023 +0000
+++ b/usr.bin/xlint/lint1/tree.c        Sat Jul 08 15:26:25 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tree.c,v 1.552 2023/07/08 12:45:43 rillig Exp $        */
+/*     $NetBSD: tree.c,v 1.553 2023/07/08 15:26:25 rillig Exp $        */
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID)
-__RCSID("$NetBSD: tree.c,v 1.552 2023/07/08 12:45:43 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.553 2023/07/08 15:26:25 rillig Exp $");
 #endif
 
 #include <float.h>
@@ -95,9 +95,7 @@ width_in_bits(const type_t *tp)
        lint_assert(is_integer(tp->t_tspec));
        return tp->t_bitfield
            ? tp->t_bit_field_width
-           // FIXME: The rank of a type is only intended as a relative size,
-           // its value is not to be taken literally.
-           : type_properties(tp->t_tspec)->tt_rank;
+           : size_in_bits(tp->t_tspec);
 }
 
 static int
@@ -3450,8 +3448,9 @@ convert_integer_from_integer(op_t op, in
            (portable_rank_cmp(ot, LONG) >= 0 || aflag > 1) &&
             // XXX: The portable_rank_cmp above aims at portable mode,
             // independent of the current platform, while can_represent acts
-            // on the actual types from the current platform.  This mix is
-            // inconsistent.
+            // on the actual type sizes from the current platform.  This mix
+            // is inconsistent, but anything else would make the exact
+            // conditions too complicated to grasp.
            !can_represent(tp, tn)) {
                if (op == FARG) {
                        /* conversion from '%s' to '%s' may lose ... */