Fix parallel build issues with parse.y and version.h/syntax.c.

(Portage version: 2.2.0_alpha59/cvs/Linux x86_64)

3 files changed, 75 insertions, 2 deletions

diff --git a/app-shells/bash/ChangeLog b/app-shells/bash/ChangeLog
index 341e66d3b211..5ba11d4b51c4 100644
--- a/app-shells/bash/ChangeLog
+++ b/app-shells/bash/ChangeLog
@@ -1,6 +1,10 @@
 # ChangeLog for app-shells/bash
 # Copyright 1999-2011 Gentoo Foundation; Distributed under the GPL v2
-# $Header: /var/cvsroot/gentoo-x86/app-shells/bash/ChangeLog,v 1.291 2011/09/16 17:25:35 vapier Exp $
+# $Header: /var/cvsroot/gentoo-x86/app-shells/bash/ChangeLog,v 1.292 2011/10/07 20:01:04 vapier Exp $
+
+  07 Oct 2011; Mike Frysinger <vapier@gentoo.org> bash-4.2_p10.ebuild,
+  +files/bash-4.2-parallel-build.patch:
+  Fix parallel build issues with parse.y and version.h/syntax.c.
 
   16 Sep 2011; Mike Frysinger <vapier@gentoo.org> bash-4.2_p10.ebuild,
   +files/bash-4.2-execute-job-control.patch:
diff --git a/app-shells/bash/bash-4.2_p10.ebuild b/app-shells/bash/bash-4.2_p10.ebuild
index a1921e4b9134..006b9c14dfd8 100644
--- a/app-shells/bash/bash-4.2_p10.ebuild
+++ b/app-shells/bash/bash-4.2_p10.ebuild
@@ -1,6 +1,6 @@
 # Copyright 1999-2011 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
-# $Header: /var/cvsroot/gentoo-x86/app-shells/bash/bash-4.2_p10.ebuild,v 1.4 2011/09/16 17:25:35 vapier Exp $
+# $Header: /var/cvsroot/gentoo-x86/app-shells/bash/bash-4.2_p10.ebuild,v 1.5 2011/10/07 20:01:04 vapier Exp $
 
 EAPI="1"
 
@@ -73,6 +73,7 @@ src_unpack() {
 	cd ../..
 
 	epatch "${FILESDIR}"/${PN}-4.2-execute-job-control.patch #383237
+	epatch "${FILESDIR}"/${PN}-4.2-parallel-build.patch
 }
 
 src_compile() {
diff --git a/app-shells/bash/files/bash-4.2-parallel-build.patch b/app-shells/bash/files/bash-4.2-parallel-build.patch
new file mode 100644
index 000000000000..9a7f36fafbd8
--- /dev/null
+++ b/app-shells/bash/files/bash-4.2-parallel-build.patch
@@ -0,0 +1,68 @@
+the current yacc rules allow multiple runs to generate the same files.  usually
+this doesn't come up as the generated files are shipped in the tarball, but
+when you modify parse.y (applying a patch or developing or whatever), you can
+hit this problem.
+
+simple way of showing this:
+	make -j y.tab.{c,h}
+a correct system would not show the yacc parser running twice :)
+
+simple patch is to have the .h file depend on the .c file, and have the .h file
+itself issue a dummy rule (to avoid make thinking things changed).
+
+--- a/Makefile.in
++++ b/Makefile.in
+@@ -579,16 +579,17 @@
+ 
+ # old rules
+ GRAM_H = parser-built
+-y.tab.o: y.tab.c ${GRAM_H} command.h ${BASHINCDIR}/stdc.h input.h
++y.tab.o: y.tab.h y.tab.c ${GRAM_H} command.h ${BASHINCDIR}/stdc.h input.h
+ ${GRAM_H}:	y.tab.h
+ 	@-if test -f y.tab.h ; then \
+ 		cmp -s $@ y.tab.h 2>/dev/null || cp -p y.tab.h $@; \
+ 	fi
+-y.tab.c y.tab.h: parse.y
++y.tab.c: parse.y
+ #	-if test -f y.tab.h; then mv -f y.tab.h old-y.tab.h; fi
+ 	$(YACC) -d $(srcdir)/parse.y
+ 	touch parser-built
+ #	-if cmp -s old-y.tab.h y.tab.h; then mv old-y.tab.h y.tab.h; else cp -p y.tab.h ${GRAM_H}; fi
++y.tab.h: y.tab.c ; @true
+ 
+ # experimental new rules - work with GNU make but not BSD (or OSF) make
+ #y.tab.o: y.tab.c y.tab.h
+
+the current code generates a bunch of local libraries in subdirs and then
+links bash against that.  those subdirs sometimes need version.h.  so they
+have a rule to change back up to the parent dir and build version.h (which is
+fine).  the trouble is that the top level objects and the subdirs are allowed
+to build in parallel, so it's possible for multiple children to see that
+version.h is not available and that it needs to be created, so they all do.
+
+there is even more trouble is that version.h depends on all the top level
+sources, some of which are compiled (like syntax.c).  so these parallel
+children all kick off a job to generate syntax.c which in turn requires the
+mksyntax helper executable.  obviously multiple processes rm-ing, compiling,
+and linking the same files quickly falls apart.
+
+so tweak the subdirs to all depend on the .build target which in turn depends
+on all of these top level files being generated.  now the subdirs won't try and
+recursively enter the top level.
+
+(noticed by David James)
+
+--- a/Makefile.in
++++ b/Makefile.in
+@@ -597,6 +598,11 @@
+ #	$(YACC) -d $(srcdir)/parse.y
+ #	-if cmp -s old-y.tab.h y.tab.h; then mv old-y.tab.h y.tab.h; fi
+ 
++# Subdirs will often times want version.h, so they'll change back up to
++# the top level and try to create it.  This causes parallel build issues
++# so just force top level sanity before we descend.
++$(LIBDEP): .build
++
+ $(READLINE_LIBRARY): config.h $(READLINE_SOURCE)
+ 	@echo making $@ in ${RL_LIBDIR}
+ 	@( { test "${RL_LIBDIR}" = "${libdir}" && exit 0; } || \