[src/trunk]: src/usr.bin/make make(1): remove redundant null checks for the a...

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

details:   https://anonhg.NetBSD.org/src/rev/77b4614e86bf
branches:  trunk
changeset: 1014608:77b4614e86bf
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Sep 27 12:26:23 2020 +0000

description:
make(1): remove redundant null checks for the active targets

Before August 2020, the Lst library passed null pointers through.  This
was a confusing design pattern that has been removed since.  Now the Lst
functions fail fast on null pointers.

The 'targets' list is one of the few places where there is indeed an
optional list that may sometimes be null.  Back then, there was not
enough inline documentation to understand when the targets list was null
and when it wasn't.

Now that the documentation is there, the redundant and thereby
misleading null checks are no longer useful.

diffstat:

 usr.bin/make/parse.c |  29 +++++++++++++----------------
 1 files changed, 13 insertions(+), 16 deletions(-)

diffs (114 lines):

diff -r a87284d9c436 -r 77b4614e86bf usr.bin/make/parse.c
--- a/usr.bin/make/parse.c      Sun Sep 27 12:10:51 2020 +0000
+++ b/usr.bin/make/parse.c      Sun Sep 27 12:26:23 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: parse.c,v 1.335 2020/09/27 12:05:04 rillig Exp $       */
+/*     $NetBSD: parse.c,v 1.336 2020/09/27 12:26:23 rillig Exp $       */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -131,7 +131,7 @@
 #include "pathnames.h"
 
 /*     "@(#)parse.c    8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: parse.c,v 1.335 2020/09/27 12:05:04 rillig Exp $");
+MAKE_RCSID("$NetBSD: parse.c,v 1.336 2020/09/27 12:26:23 rillig Exp $");
 
 /* types and constants */
 
@@ -214,7 +214,9 @@
 
 /* eval state */
 
-/* During parsing, the targets from the previous dependency line.
+/* During parsing, the targets from the currently active dependency line,
+ * or NULL if the current line does not belong to a dependency line, for
+ * example because it is a variable assignment.
  *
  * See unit-tests/deptgt.mk, keyword "parse.c:targets". */
 static GNodeList *targets;
@@ -931,8 +933,7 @@
        if (keywd != -1) {
            int op = parseKeywords[keywd].op;
            if (op != 0) {
-               if (targets != NULL)
-                   Lst_ForEachUntil(targets, ParseDoOp, &op);
+               Lst_ForEachUntil(targets, ParseDoOp, &op);
                return;
            }
            if (parseKeywords[keywd].spec == Wait) {
@@ -950,7 +951,7 @@
                if (doing_depend)
                    ParseMark(gn);
                gn->type = OP_WAIT | OP_PHONY | OP_DEPENDS | OP_NOTMAIN;
-               if (targets != NULL) {
+               {
                    struct ParseLinkSrcArgs args = { gn, specType };
                    Lst_ForEach(targets, ParseLinkSrc, &args);
                }
@@ -1021,7 +1022,7 @@
        if (tOp) {
            gn->type |= tOp;
        } else {
-           if (targets != NULL) {
+           {
                struct ParseLinkSrcArgs args = { gn, specType };
                Lst_ForEach(targets, ParseLinkSrc, &args);
            }
@@ -1040,8 +1041,6 @@
 
     if (mainNode != NULL)
         return;
-    if (targets == NULL)
-       return;
 
     for (ln = targets->first; ln != NULL; ln = ln->next) {
        GNode *gn = ln->datum;
@@ -1188,7 +1187,7 @@
      * First, grind through the targets.
      */
 
-    while (TRUE) {
+    for (;;) {
        /*
         * Here LINE points to the beginning of the next word, and
         * LSTART points to the actual beginning of the line.
@@ -1434,7 +1433,7 @@
     Lst_Free(curTargs);
     curTargs = NULL;
 
-    if (targets != NULL && !Lst_IsEmpty(targets)) {
+    if (!Lst_IsEmpty(targets)) {
        switch(specType) {
            default:
                Parse_Error(PARSE_WARNING, "Special and mundane targets don't mix. Mundane ones ignored");
@@ -1484,8 +1483,7 @@
      * operator a target was defined with. It fails if the operator
      * used isn't consistent across all references.
      */
-    if (targets != NULL)
-       Lst_ForEachUntil(targets, ParseDoOp, &op);
+    Lst_ForEachUntil(targets, ParseDoOp, &op);
 
     /*
      * Onward to the sources.
@@ -2802,8 +2800,8 @@
     if (targets != NULL) {
        Lst_ForEach(targets, SuffEndTransform, NULL);
        Lst_Destroy(targets, ParseHasCommands);
+       targets = NULL;
     }
-    targets = NULL;
 }
 
 /* Add the command to each target from the current dependency spec. */
@@ -3101,8 +3099,7 @@
 {
 #ifdef CLEANUP
     Lst_Destroy(targCmds, free);
-    if (targets)
-       Lst_Free(targets);
+    assert(targets == NULL);
     Lst_Destroy(defIncPath, Dir_Destroy);
     Lst_Destroy(sysIncPath, Dir_Destroy);
     Lst_Destroy(parseIncPath, Dir_Destroy);