elide duplicate dummy dependencies as we concatenate them to a library depfile

1 files changed, 50 insertions, 0 deletions

diff --git a/solenv/bin/concat-deps.pl b/solenv/bin/concat-deps.pl
new file mode 100755
index 000000000000..a9788cb0ac3f
--- /dev/null
+++ b/solenv/bin/concat-deps.pl
@@ -0,0 +1,50 @@
+#! /usr/bin/env perl
+
+# reads a list of dependency files from a file, opens and
+# concatenates them, while eliding duplicate nop rules.
+
+sub read_depfiles($)
+{
+    my $name = shift;
+    my $depfh;
+    my @files;
+    open ($depfh, $name) || die "Can't open list of dependencies: $name: $!";
+    while (<$depfh>) {
+	push @files, split(/\s+/, $_);
+    }
+    close ($depfh);
+
+#    print STDERR "dep files: " . join ("'", @files) . "\n";
+    return @files;
+}
+
+my @depfiles = read_depfiles (shift @ARGV);
+
+my %rules;
+print "# concatenated, reduced dependencies generated by solenv/bin/concat-deps.pl\n";
+
+for my $fname (@depfiles) {
+    my $fileh;
+
+    next if ($fname eq '');
+    open ($fileh, $fname) || die "Can't open $fname: $!\n";
+
+    my $last = '';
+    while (<$fileh>) {
+	my $line = $_;
+	if ($line eq "\n") {
+	    if ($last =~ /^(.*):\s*$/) {
+		if (defined $rules{$1}) {
+		    $last = '';
+		    next;
+		}
+		$rules{$1} = 1;
+	    }
+	}
+	print $last;
+	$last = $line;
+    }
+    print $last;
+
+    close ($fileh);
+}