[src/trunk]: src/usr.bin/xlint/lint1 tests/lint: explain difference between i...

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

details:   https://anonhg.NetBSD.org/src/rev/edc8c4843e39
branches:  trunk
changeset: 987429:edc8c4843e39
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Sep 26 14:52:37 2021 +0000

description:
tests/lint: explain difference between i386 and sparc for 259

Seen in usr.bin/make/cond.c 1.278 from 2021-09-21, line 800, the call to
is_token, where unsigned char gets converted to unsigned int or unsigned
long, depending on the platform.

diffstat:

 tests/usr.bin/xlint/lint1/platform_int.c    |   9 ++++++++-
 tests/usr.bin/xlint/lint1/platform_int.exp  |   2 +-
 tests/usr.bin/xlint/lint1/platform_long.c   |  16 ++++++++++++++--
 tests/usr.bin/xlint/lint1/platform_long.exp |   2 +-
 usr.bin/xlint/lint1/tree.c                  |   8 ++++++--
 5 files changed, 30 insertions(+), 7 deletions(-)

diffs (100 lines):

diff -r a55795257633 -r edc8c4843e39 tests/usr.bin/xlint/lint1/platform_int.c
--- a/tests/usr.bin/xlint/lint1/platform_int.c  Sun Sep 26 14:32:02 2021 +0000
+++ b/tests/usr.bin/xlint/lint1/platform_int.c  Sun Sep 26 14:52:37 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: platform_int.c,v 1.2 2021/09/26 14:28:22 rillig Exp $  */
+/*     $NetBSD: platform_int.c,v 1.3 2021/09/26 14:52:37 rillig Exp $  */
 # 3 "platform_int.c"
 
 /*
@@ -11,9 +11,16 @@
 
 void to_size(typeof(sizeof(int)));
 
+/* See should_warn_about_prototype_conversion. */
 void
 convert_unsigned_char_to_size(unsigned char uc)
 {
+       /*
+        * In this function call, uc is first promoted to INT. It is then
+        * converted to size_t, which is UINT. The portable bit size of INT
+        * and UINT is the same, 32, but the signedness changes, therefore
+        * the warning.
+        */
        /* expect+1: warning: argument #1 is converted from 'unsigned char' to 'unsigned int' due to prototype [259] */
        to_size(uc);
 }
diff -r a55795257633 -r edc8c4843e39 tests/usr.bin/xlint/lint1/platform_int.exp
--- a/tests/usr.bin/xlint/lint1/platform_int.exp        Sun Sep 26 14:32:02 2021 +0000
+++ b/tests/usr.bin/xlint/lint1/platform_int.exp        Sun Sep 26 14:52:37 2021 +0000
@@ -1,1 +1,1 @@
-platform_int.c(18): warning: argument #1 is converted from 'unsigned char' to 'unsigned int' due to prototype [259]
+platform_int.c(25): warning: argument #1 is converted from 'unsigned char' to 'unsigned int' due to prototype [259]
diff -r a55795257633 -r edc8c4843e39 tests/usr.bin/xlint/lint1/platform_long.c
--- a/tests/usr.bin/xlint/lint1/platform_long.c Sun Sep 26 14:32:02 2021 +0000
+++ b/tests/usr.bin/xlint/lint1/platform_long.c Sun Sep 26 14:52:37 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: platform_long.c,v 1.2 2021/09/26 14:28:22 rillig Exp $ */
+/*     $NetBSD: platform_long.c,v 1.3 2021/09/26 14:52:37 rillig Exp $ */
 # 3 "platform_long.c"
 
 /*
@@ -11,10 +11,22 @@
 
 void to_size(typeof(sizeof(int)));
 
+/* See should_warn_about_prototype_conversion. */
 void
 convert_unsigned_char_to_size(unsigned char uc)
 {
-       /* no warning, unlike in platform_int */
+       /*
+        * In this function call, uc is first promoted to INT. It is then
+        * converted to size_t, which is ULONG. The portable bit size of INT
+        * is 24 (see INT_RSIZE in inittyp.c), which is less than the 32 of
+        * ULONG. Since the portable bit size increases from 24 to 32, there
+        * is no warning.
+        *
+        * XXX: Investigate whether this rule makes sense. Warning 259 is
+        * about prototype mismatch, not about lossy integer conversions,
+        * and there is a clear mismatch here between INT and LONG,
+        * therefore a warning makes sense.
+        */
        to_size(uc);
 }
 
diff -r a55795257633 -r edc8c4843e39 tests/usr.bin/xlint/lint1/platform_long.exp
--- a/tests/usr.bin/xlint/lint1/platform_long.exp       Sun Sep 26 14:32:02 2021 +0000
+++ b/tests/usr.bin/xlint/lint1/platform_long.exp       Sun Sep 26 14:52:37 2021 +0000
@@ -1,1 +1,1 @@
-platform_long.c(22): warning: static variable unused_variable unused [226]
+platform_long.c(34): warning: static variable unused_variable unused [226]
diff -r a55795257633 -r edc8c4843e39 usr.bin/xlint/lint1/tree.c
--- a/usr.bin/xlint/lint1/tree.c        Sun Sep 26 14:32:02 2021 +0000
+++ b/usr.bin/xlint/lint1/tree.c        Sun Sep 26 14:52:37 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tree.c,v 1.382 2021/09/18 10:46:17 jmcneill Exp $      */
+/*     $NetBSD: tree.c,v 1.383 2021/09/26 14:52:37 rillig Exp $        */
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID) && !defined(lint)
-__RCSID("$NetBSD: tree.c,v 1.382 2021/09/18 10:46:17 jmcneill Exp $");
+__RCSID("$NetBSD: tree.c,v 1.383 2021/09/26 14:52:37 rillig Exp $");
 #endif
 
 #include <float.h>
@@ -2035,6 +2035,10 @@
                /* representation and/or width change */
                if (!is_integer(ot))
                        return true;
+               /*
+                * XXX: Investigate whether this rule makes sense; see
+                * tests/usr.bin/xlint/lint1/platform_long.c.
+                */
                return portable_size_in_bits(ot) > portable_size_in_bits(INT);
        }