[src/trunk]: src/usr.bin/xlint/lint1 lint: prevent undefined behavior when fo...

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

details:   https://anonhg.NetBSD.org/src/rev/13e502f891e3
branches:  trunk
changeset: 368279:13e502f891e3
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat Jul 02 10:47:29 2022 +0000

description:
lint: prevent undefined behavior when folding '<<' or '>>'

diffstat:

 usr.bin/xlint/lint1/tree.c |  12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diffs (39 lines):

diff -r 817482e1f31a -r 13e502f891e3 usr.bin/xlint/lint1/tree.c
--- a/usr.bin/xlint/lint1/tree.c        Sat Jul 02 10:41:13 2022 +0000
+++ b/usr.bin/xlint/lint1/tree.c        Sat Jul 02 10:47:29 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tree.c,v 1.468 2022/07/02 10:41:13 rillig Exp $        */
+/*     $NetBSD: tree.c,v 1.469 2022/07/02 10:47:29 rillig Exp $        */
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID)
-__RCSID("$NetBSD: tree.c,v 1.468 2022/07/02 10:41:13 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.469 2022/07/02 10:47:29 rillig Exp $");
 #endif
 
 #include <float.h>
@@ -3507,16 +3507,16 @@
                        ovfl = true;
                break;
        case SHL:
-               /* TODO: warn against out-of-bounds 'sr'. */
-               q = utyp ? (int64_t)(ul << sr) : sl << sr;
+               /* TODO: warn about out-of-bounds 'sr'. */
+               q = utyp ? (int64_t)(ul << (sr & 63)) : sl << (sr & 63);
                break;
        case SHR:
                /*
                 * The sign must be explicitly extended because
                 * shifts of signed values are implementation dependent.
                 */
-               /* TODO: warn against out-of-bounds 'sr'. */
-               q = ul >> sr;
+               /* TODO: warn about out-of-bounds 'sr'. */
+               q = ul >> (sr & 63);
                q = convert_integer(q, t, size_in_bits(t) - (int)sr);
                break;
        case LT: