[src/trunk]: src/usr.bin/make make: clean up parsing of variable assignments

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

details:   https://anonhg.NetBSD.org/src/rev/5dd2eda1364e
branches:  trunk
changeset: 1027630:5dd2eda1364e
user:      rillig <rillig%NetBSD.org@localhost>
date:      Tue Dec 14 00:17:53 2021 +0000

description:
make: clean up parsing of variable assignments

Assign pairs of variables in a consistent order, as far as possible.

Use string functions instead of raw byte access, to make the code more
human-readable.  GCC 10 optimizes the code reasonably.

No functional change.

diffstat:

 usr.bin/make/parse.c |  17 ++++++++---------
 1 files changed, 8 insertions(+), 9 deletions(-)

diffs (68 lines):

diff -r 2842401818e9 -r 5dd2eda1364e usr.bin/make/parse.c
--- a/usr.bin/make/parse.c      Tue Dec 14 00:02:57 2021 +0000
+++ b/usr.bin/make/parse.c      Tue Dec 14 00:17:53 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: parse.c,v 1.578 2021/12/14 00:02:57 rillig Exp $       */
+/*     $NetBSD: parse.c,v 1.579 2021/12/14 00:17:53 rillig Exp $       */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -109,7 +109,7 @@
 #include "pathnames.h"
 
 /*     "@(#)parse.c    8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: parse.c,v 1.578 2021/12/14 00:02:57 rillig Exp $");
+MAKE_RCSID("$NetBSD: parse.c,v 1.579 2021/12/14 00:17:53 rillig Exp $");
 
 /* types and constants */
 
@@ -1732,8 +1732,8 @@
        VarAssignOp type;
 
        if (op > name && op[-1] == '+') {
+               op--;
                type = VAR_APPEND;
-               op--;
 
        } else if (op > name && op[-1] == '?') {
                op--;
@@ -1753,10 +1753,9 @@
                while (op > name && ch_isspace(op[-1]))
                        op--;
 
-               if (op >= name + 3 && op[-3] == ':' && op[-2] == 's' &&
-                   op[-1] == 'h') {
+               if (op >= name + 3 && memcmp(op - 3, ":sh", 3) == 0) {
+                       op -= 3;
                        type = VAR_SHELL;
-                       op -= 3;
                }
 #endif
        }
@@ -1979,7 +1978,7 @@
                Var_ExportVars(avalue);
 }
 
-/* Perform the variable variable assignment in the given scope. */
+/* Perform the variable assignment in the given scope. */
 void
 Parse_Var(VarAssign *var, GNode *scope)
 {
@@ -2009,7 +2008,7 @@
                char endc;
 
                /* XXX: What if progname != "make"? */
-               if (p[0] == 'm' && p[1] == 'a' && p[2] == 'k' && p[3] == 'e')
+               if (strncmp(p, "make", 4) == 0)
                        if (start == cmd || !ch_isalnum(p[-1]))
                                if (!ch_isalnum(p[4]))
                                        return true;
@@ -2029,7 +2028,7 @@
                if (*p == '.')  /* Accept either ${.MAKE} or ${MAKE}. */
                        p++;
 
-               if (p[0] == 'M' && p[1] == 'A' && p[2] == 'K' && p[3] == 'E')
+               if (strncmp(p, "MAKE", 4) == 0)
                        if (p[4] == endc)
                                return true;
        }