major overhaul of the way make handle jobs, inspired by dpb:

instead of forking a "job" per target, and having that job further fork
separate commands, have make maintain a list of jobs, indexed by pid
of currently running commands, and handle process termination
continuation-style.  This has lots of benefits:
- make is responsible for most printing, so we no longer need pipes nor
job control: make -j jobs see the tty.
- no more special-casing for jobs that don't really execute anything.
- unify code for make -jn and make -B, including signal handlers and
job waiting.  So make -n, make -q, +cmd now run commands in the same
way in all cases.
- unified more accurate error-reporting, as make knows precisely which
command failed. Commands are tagged with their lines, and we display failing
commands in silent mode.
- fine-grained "expensive" command handling (recursion limiter). Do it
per-command instead of per-target.

Moreover, signal response is now simpler, as we just block the signals
in a small critical sections, test for events, and sigpause (thanks a lot
to guenther@ and millert@), so running make is now almost always paused
without any busy-waiting.

Thanks to everyone who tested and gave input.

1 files changed, 4 insertions, 1 deletions

diff --git a/usr.bin/make/buf.h b/usr.bin/make/buf.h
index 980d15a9546..4806b434b51 100644
--- a/usr.bin/make/buf.h
+++ b/usr.bin/make/buf.h
@@ -1,7 +1,7 @@
 #ifndef _BUF_H
 #define _BUF_H
 
-/*	$OpenBSD: buf.h,v 1.19 2010/07/19 19:46:43 espie Exp $	*/
+/*	$OpenBSD: buf.h,v 1.20 2012/09/21 07:55:20 espie Exp $	*/
 /*	$NetBSD: buf.h,v 1.7 1996/12/31 17:53:22 christos Exp $ */
 
 /*
@@ -133,4 +133,7 @@ do {						\
  *	Removes non-backslashed spaces at the end of a buffer. */
 extern void Buf_KillTrailingSpaces(Buffer);
 
+extern void Buf_printf(Buffer, const char *, ...);
+#define Buf_puts(b, s)	Buf_AddChars((b), strlen(s), (s))
+
 #endif /* _BUF_H */