[src/trunk]: src/usr.bin/make make(1): remove UNCONST from Dir_Expand

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

details:   https://anonhg.NetBSD.org/src/rev/57528a416bad
branches:  trunk
changeset: 941591:57528a416bad
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat Oct 24 23:27:33 2020 +0000

description:
make(1): remove UNCONST from Dir_Expand

That code is called so seldom that one more memory allocation doesn't
hurt.  It needs a wildcard character in a dependency declaration, which
is rare in practice; see dep-wildcards.mk for an example.

diffstat:

 usr.bin/make/dir.c |  14 +++++---------
 1 files changed, 5 insertions(+), 9 deletions(-)

diffs (46 lines):

diff -r 4011a87f921e -r 57528a416bad usr.bin/make/dir.c
--- a/usr.bin/make/dir.c        Sat Oct 24 23:06:15 2020 +0000
+++ b/usr.bin/make/dir.c        Sat Oct 24 23:27:33 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: dir.c,v 1.173 2020/10/24 09:18:09 rillig Exp $ */
+/*     $NetBSD: dir.c,v 1.174 2020/10/24 23:27:33 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -135,7 +135,7 @@
 #include "job.h"
 
 /*     "@(#)dir.c      8.2 (Berkeley) 1/2/94"  */
-MAKE_RCSID("$NetBSD: dir.c,v 1.173 2020/10/24 09:18:09 rillig Exp $");
+MAKE_RCSID("$NetBSD: dir.c,v 1.174 2020/10/24 23:27:33 rillig Exp $");
 
 #define DIR_DEBUG0(text) DEBUG0(DIR, text)
 #define DIR_DEBUG1(fmt, arg1) DEBUG1(DIR, fmt, arg1)
@@ -808,7 +808,6 @@
  *
  * Side Effects:
  *     Directories may be opened. Who knows?
- *     Undefined behavior if the word is really in read-only memory.
  *-----------------------------------------------------------------------
  */
 void
@@ -850,16 +849,13 @@
                    cp--;
                }
                if (cp != word) {
-                   char sc;
-                   char *dirpath;
+                   char *prefix = bmake_strsedup(word, cp + 1);
                    /*
                     * If the glob isn't in the first component, try and find
                     * all the components up to the one with a wildcard.
                     */
-                   sc = cp[1];
-                   ((char *)UNCONST(cp))[1] = '\0';
-                   dirpath = Dir_FindFile(word, path);
-                   ((char *)UNCONST(cp))[1] = sc;
+                   char *dirpath = Dir_FindFile(prefix, path);
+                   free(prefix);
                    /*
                     * dirpath is null if can't find the leading component
                     * XXX: Dir_FindFile won't find internal components.