From 92751409f7e9c403cbfeb503cc494279c712c9ab Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Sat, 29 Oct 2016 13:28:03 -0700
Subject: Provide mechanism to track library dependencies

Now, ar/lib rules can list static libraries or other .d files. These (as well as
the target library) are written to a file called $lib.d. link/exe rules can list
these .d files, causing them to be flattened into an RSP file and appear on the
command line as @$rsp.

The rule to generate the dependency list files depends on the libraries they
contain, so they also act as a stamp file for the dependencies. This gives us
dependency management for free.
---
 ninja.rc        | 26 ++++++++++++++++++++++----
 rules.ninja     |  5 +++++
 scripts/rsp.awk | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 4 deletions(-)
 create mode 100644 scripts/rsp.awk

diff --git a/ninja.rc b/ninja.rc
index 0733e2d3..d1f3550b 100644
--- a/ninja.rc
+++ b/ninja.rc
@@ -74,24 +74,42 @@ fn cc {
 }
 
 fn link {
-	out='$outdir'/$1 objs=() {
+	out='$outdir'/$1 objs=() deps=() {
 		shift
 		for(obj in $*) {
 			if(! ~ $obj '$'*) obj='$outdir'/$obj
-			objs=($objs $obj)
+			switch($obj) {
+			case *.d
+				deps=($deps $obj)
+			case *
+				objs=($objs $obj)
+			}
+		}
+		if(! ~ $#deps 0) {
+			build $out.rsp awk $deps '|' scripts/rsp.awk ; with expr '-f scripts/rsp.awk'
+			objs=($objs '|' $out.rsp)
 		}
 		build $out link $objs
+		if(! ~ $#deps 0)
+			with ldlibs @$out.rsp
+		status=()
 	}
 }
 
 fn ar {
-	out='$outdir'/$1 objs=() {
+	out='$outdir'/$1 objs=() deps=() {
 		shift
 		for(obj in $*) {
 			if(! ~ $obj '$'*) obj='$outdir'/$obj
-			objs=($objs $obj)
+			switch($obj) {
+			case *.[ad]
+				deps=($deps $obj)
+			case *
+				objs=($objs $obj)
+			}
 		}
 		build $out ar $objs
+		build $out.d lines $out $deps
 	}
 }
 
diff --git a/rules.ninja b/rules.ninja
index 45821074..6ab2b0da 100644
--- a/rules.ninja
+++ b/rules.ninja
@@ -17,6 +17,11 @@ rule link
 rule ar
   command = rm -f $out && $ar crs $out $in
 
+rule lines
+  command = ln -f $rspfile $out
+  rspfile = $out.tmp
+  rspfile_content = $in_newline
+
 rule nasm
   command = nasm $nasmflags -o $out $in
 
diff --git a/scripts/rsp.awk b/scripts/rsp.awk
new file mode 100644
index 00000000..d157e249
--- /dev/null
+++ b/scripts/rsp.awk
@@ -0,0 +1,34 @@
+function line() {
+	if (match($0, /\.d$/))
+		read($0)
+	else
+		libs[++n] = $0
+}
+
+function read(name) {
+	for (;;) {
+		ret = getline < name
+		if (ret < 0) {
+			print "failed to read line from " name > "/proc/self/fd/2"
+			exit(1)
+		}
+		if (ret == 0)
+			break
+		line()
+	}
+	close(name)
+}
+
+{line()}
+
+END {
+	for (i = n; i > 0; --i) {
+		lib = libs[i]
+		if (lib in seen)
+			continue
+		seen[lib] = 1
+		uniq[++m] = lib
+	}
+	for (i = m; i > 0; --i)
+		print uniq[i]
+}
-- 
cgit v1.2.3