From 8eed4cdd8812dffe77b82501dc08e1ef96b32275 Mon Sep 17 00:00:00 2001
From: Andrew Johnson <anj@aps.anl.gov>
Date: Sun, 27 Jul 2014 23:37:58 -0500
Subject: [PATCH] Perl DBD Parser: Autovivify record types in device() entries

If a record type named in a device() entry does not exist when
the device is seen, the DBD parser will now print a warning
and create an empty record type with that name to hold the
device entry information.
This will allow support modules to be built into libraries that
include their own registerRecordDeviceDriver code, which was
apparently possible with 3.14 although not officially supported.
To avoid the warning message, the DBD file can declare each
record type before the device statement that uses it.

A record type declaration looks like this:
    recordtype(ao) {}
    device(ao, ....)
An IOC will accept and ignore a record type declaration, but it
must have loaded the full record type definition first.
---
 src/tools/DBD/Parser.pm | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/tools/DBD/Parser.pm b/src/tools/DBD/Parser.pm
index 8cace9c17..b8cc82783 100644
--- a/src/tools/DBD/Parser.pm
+++ b/src/tools/DBD/Parser.pm
@@ -59,9 +59,12 @@ sub ParseDBD {
                           \s* $RXstr \s* , \s*$RXstr \s* \)/oxgc) {
             print "Device: $1, $2, $3, $4\n" if $debug;
             my $rtyp = $dbd->recordtype($1);
-            dieContext("Unknown record type '$1'")
-                unless defined $rtyp;
-            $rtyp->add_device(DBD::Device->new($2, $3, $4));
+	    if (!defined $rtyp) {
+	        $rtyp = DBD::Recordtype->new($1);
+		warn "Device using undefined record type '$1', place-holder created\n";
+		$dbd->add($rtyp);
+            }
+	    $rtyp->add_device(DBD::Device->new($2, $3, $4));
         } else {
             last unless m/\G (.*) $/moxgc;
             dieContext("Syntax error in '$1'");