From 5e0ee893cdb9e42d7454624fd46fd6979688ba90 Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <riastradh@NetBSD.org>
Date: Mon, 30 Jul 2018 21:30:31 +0000
Subject: [PATCH] Tag each .c file with the options that might have brought it
 in.

---
 usr.bin/config/mkmakefile.c | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/usr.bin/config/mkmakefile.c b/usr.bin/config/mkmakefile.c
index eebc5086b4b5..63e773363b4b 100644
--- a/usr.bin/config/mkmakefile.c
+++ b/usr.bin/config/mkmakefile.c
@@ -584,6 +584,36 @@ emitincludes(FILE *fp)
 }
 
 /*
+ * Emit all options included in a conditional expression
+ */
+static void
+emitopts(FILE *fp, struct condexpr *cond, int include)
+{
+
+again:	switch (cond->cx_type) {
+	case CX_ATOM:
+		if (include) {
+			fprintf(fp, " %s", cond->cx_u.atom);
+		}
+		break;
+	case CX_NOT:
+		cond = cond->cx_u.not;
+		include = !include;
+		goto again;
+	case CX_AND:
+		emitopts(fp, cond->cx_u.and.left, include);
+		cond = cond->cx_u.and.right;
+		goto again;
+	case CX_OR:
+		emitopts(fp, cond->cx_u.and.left, include);
+		cond = cond->cx_u.and.right;
+		goto again;
+	default:
+		cfgerror("bug");
+	}
+}
+
+/*
  * Emit appending makeoptions.
  */
 static void
@@ -591,6 +621,17 @@ emitappmkoptions(FILE *fp)
 {
 	struct nvlist *nv;
 	struct condexpr *cond;
+	size_t i;
+
+	for (i = 0; i < nselfiles; i++) {
+		struct files *const fi = selfiles[i];
+
+		if (fi->fi_optx) {
+			fprintf(fp, "OPT.%s.c+=", fi->fi_base);
+			emitopts(fp, fi->fi_optx, 1);
+			fprintf(fp, "\n");
+		}
+	}
 
 	for (nv = appmkoptions; nv != NULL; nv = nv->nv_next)
 		fprintf(fp, "%s+=%s\n", nv->nv_name, nv->nv_str);
-- 
2.11.0