[src/trunk]: src/usr.bin/make meta.c: add .MAKE.META.CMP_FILTER

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

details:   https://anonhg.NetBSD.org/src/rev/cb45595c0e53
branches:  trunk
changeset: 359600:cb45595c0e53
user:      sjg <sjg%NetBSD.org@localhost>
date:      Thu Jan 13 04:51:50 2022 +0000

description:
meta.c: add .MAKE.META.CMP_FILTER

On rare occasions it is useful to be able to filter command lines
before comparison.

diffstat:

 usr.bin/make/make.1 |  10 ++++++++--
 usr.bin/make/meta.c |  46 ++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 52 insertions(+), 4 deletions(-)

diffs (119 lines):

diff -r 7c95b0d529c9 -r cb45595c0e53 usr.bin/make/make.1
--- a/usr.bin/make/make.1       Thu Jan 13 00:21:41 2022 +0000
+++ b/usr.bin/make/make.1       Thu Jan 13 04:51:50 2022 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: make.1,v 1.300 2021/12/12 20:45:48 sjg Exp $
+.\"    $NetBSD: make.1,v 1.301 2022/01/13 04:51:50 sjg Exp $
 .\"
 .\" Copyright (c) 1990, 1993
 .\"    The Regents of the University of California.  All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\"    from: @(#)make.1        8.4 (Berkeley) 3/19/94
 .\"
-.Dd December 12, 2021
+.Dd January 12, 2022
 .Dt MAKE 1
 .Os
 .Sh NAME
@@ -954,6 +954,12 @@
 .Va .OBJDIR
 but within said bailiwick is missing,
 the current target is considered out-of-date.
+.It Va .MAKE.META.CMP_FILTER
+In "meta" mode, it can (very rarely!) be useful to filter command
+lines before comparison.
+This variable can be set to a set of modifiers that will be applied to
+each line of the old and new command that differ, if the filtered
+commands still differ, the target is considered out-of-date.
 .It Va .MAKE.META.CREATED
 In "meta" mode, this variable contains a list of all the meta files
 updated.
diff -r 7c95b0d529c9 -r cb45595c0e53 usr.bin/make/meta.c
--- a/usr.bin/make/meta.c       Thu Jan 13 00:21:41 2022 +0000
+++ b/usr.bin/make/meta.c       Thu Jan 13 04:51:50 2022 +0000
@@ -1,4 +1,4 @@
-/*      $NetBSD: meta.c,v 1.186 2021/12/13 01:51:12 rillig Exp $ */
+/*      $NetBSD: meta.c,v 1.187 2022/01/13 04:51:50 sjg Exp $ */
 
 /*
  * Implement 'meta' mode.
@@ -65,6 +65,9 @@
 #ifndef MAKE_META_IGNORE_FILTER
 #define MAKE_META_IGNORE_FILTER ".MAKE.META.IGNORE_FILTER"
 #endif
+#ifndef MAKE_META_CMP_FILTER
+#define MAKE_META_CMP_FILTER ".MAKE.META.CMP_FILTER"
+#endif
 
 bool useMeta = false;
 static bool useFilemon = false;
@@ -76,6 +79,7 @@
 static bool metaIgnoreCMDs = false;    /* ignore CMDs in .meta files */
 static bool metaIgnorePatterns = false; /* do we need to do pattern matches */
 static bool metaIgnoreFilter = false;  /* do we have more complex filtering? */
+static bool metaCmpFilter = false;     /* do we have CMP_FILTER ? */
 static bool metaCurdirOk = false;      /* write .meta in .CURDIR Ok? */
 static bool metaSilent = false;                /* if we have a .meta be SILENT */
 
@@ -661,6 +665,11 @@
        metaIgnoreFilter = true;
        FStr_Done(&value);
     }
+    value = Var_Value(SCOPE_GLOBAL, MAKE_META_CMP_FILTER);
+    if (value.str != NULL) {
+       metaCmpFilter = true;
+       FStr_Done(&value);
+    }
 }
 
 /*
@@ -1077,6 +1086,39 @@
     Lst_Append(list, bmake_strdup(str));
 }
 
+static char *
+meta_filter_cmd(Buffer *buf, GNode *gn, char *s)
+{
+    Buf_Clear(buf);
+    Buf_AddStr(buf, "${");
+    Buf_AddStr(buf, s);
+    Buf_AddStr(buf, ":L:${" MAKE_META_CMP_FILTER ":ts:}}");
+    Var_Subst(buf->data, gn, VARE_WANTRES, &s);
+    return s;
+}
+    
+static int
+meta_cmd_cmp(GNode *gn, char *a, char *b)
+{
+    static int once = 0;
+    static Buffer buf;
+    int rc;
+
+    rc = strcmp(a, b);
+    if (rc == 0 || !metaCmpFilter)
+       return rc;
+    if (!once) {
+       once++;
+       Buf_InitSize(&buf, BUFSIZ);
+    }
+    a = meta_filter_cmd(&buf, gn, a);
+    b = meta_filter_cmd(&buf, gn, b);
+    rc = strcmp(a, b);
+    free(a);
+    free(b);
+    return rc;
+}
+
 bool
 meta_oodate(GNode *gn, bool oodate)
 {
@@ -1552,7 +1594,7 @@
                    if (p != NULL &&
                        !hasOODATE &&
                        !(gn->type & OP_NOMETA_CMP) &&
-                       (strcmp(p, cmd) != 0)) {
+                       (meta_cmd_cmp(gn, p, cmd) != 0)) {
                        DEBUG4(META, "%s: %d: a build command has changed\n%s\nvs\n%s\n",
                               fname, lineno, p, cmd);
                        if (!metaIgnoreCMDs)