From 3d8c4d1ed095ef10e24e1a81cdbe53c3600d4834 Mon Sep 17 00:00:00 2001
From: Mike Gerwitz <mike.gerwitz@ryansg.com>
Date: Thu, 28 Sep 2023 10:12:40 -0400
Subject: [PATCH] preproc/domain: Eliminate duplicate domain generation

I have long forgotten about this system.  It converts typedefs into a more
generic domain, but the way in which it does so causes duplicate domains,
for two reasons:

  - Both `preproc:mkdomain` and the caller (`preproc:expand`) recurse into
    unions and generate domains; and
  - Each `preproc:expand` pass generates domains.

So, for example, if there are two `preproc:expand` passes on a union, then
the outer typedef (union) will have domains generated twice (once for each
pass), and the inner typedefs will have domains generated four times (for
each expansion pass, and twice for each pass).

This resolves the issue before the next commit makes further changes to move
this into a generated header file.
---
 src/current/include/preproc/domain.xsl |  5 ++---
 src/current/include/preproc/expand.xsl | 10 +++++++---
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/current/include/preproc/domain.xsl b/src/current/include/preproc/domain.xsl
index 435532e8..308bbb08 100644
--- a/src/current/include/preproc/domain.xsl
+++ b/src/current/include/preproc/domain.xsl
@@ -54,7 +54,6 @@
   "
   mode="preproc:mkdomain" priority="5">
 
-  <!-- generate all contained domains -->
   <variable name="subdomains">
     <variable name="union-types" select="
       lv:union/lv:typedef" />
@@ -70,7 +69,7 @@
     </if>
 
     <apply-templates mode="preproc:mkdomain"
-      select="$union-types" />
+                     select="$union-types" />
   </variable>
 
   <!-- provide a denormalized domain for performance and to reduce
@@ -80,7 +79,7 @@
     <with-param name="subdomains" select="$subdomains" />
   </call-template>
 
-  <copy-of select="$subdomains" />
+  <sequence select="$subdomains" />
 </template>
 
 
diff --git a/src/current/include/preproc/expand.xsl b/src/current/include/preproc/expand.xsl
index 2a1555d0..e337736f 100644
--- a/src/current/include/preproc/expand.xsl
+++ b/src/current/include/preproc/expand.xsl
@@ -85,10 +85,14 @@
 <!--
   Domain data are extracted from typedefs
 
-  Eventually, the typedefs will be converted into templates and removed entirely.
+  We must be sure that we (a) have not yet processed this typedef and (b)
+  that we do not handle nested typedefs (within unions), since that is done
+  for us by `preproc:mkdomain`.
 -->
-<template match="lv:typedef"
-  mode="preproc:expand" priority="5">
+<template match="lv:typedef[
+                   not( preceding-sibling::lv:domain/@name = @name )
+                   and not( ancestor::lv:union ) ]"
+          mode="preproc:expand" priority="5">
 
   <apply-templates select="." mode="preproc:mkdomain" />