PATCH: Make Makefile.am work in parallel

[Mark Mitchell <mark at codesourcery dot com>]

I got annoyed that Makefile.am wants to generate class files in serial.

This is particularly irksome when you have lots of processors (hundreds),
but they are all slow (MIPS R10K 250s).

There were some commments in the Makefile I didn't understand, but here's
the patch I came up with.   It seems to work, and I can't see why it
should behave differently than what was there before.

Assuming the tests go OK, does anyone object to this patch?

--
Mark Mitchell                   mark@codesourcery.com
CodeSourcery, LLC               http://www.codesourcery.com

Index: Makefile.am
===================================================================
RCS file: /cvs/gcc/gcc/libjava/Makefile.am,v
retrieving revision 1.215
diff -c -p -r1.215 Makefile.am
*** Makefile.am	26 Apr 2002 22:39:28 -0000	1.215
--- Makefile.am	6 May 2002 23:08:05 -0000
*************** install-exec-hook:
*** 165,209 ****
  	  $(LN_S) libgcjx.la gnu-awt-xlib.la; \
  	fi

! ## Make the .class files depend on the .zip file.  This seems
! ## backwards, but is right.  This doesn't catch all the .class files,
! ## but that is ok, because the ones it fails to pick up are defined in
! ## a .java file with some other class which is caught.  Note that we
! ## only want to create headers for those files which do not have
! ## hand-maintained headers.
! $(built_java_source_files:.java=.class): libgcj-@gcc_version@.jar
! $(java_source_files:.java=.class): libgcj-@gcc_version@.jar

! ## The .class files for X will not be included in libgcj.jar, but the
! ## rule for libgcj.jar will cause all out-of-date .class files to be
! ## built. We need this to generate headers for the nat-files.
! $(x_java_source_files:.java=.class): libgcj-@gcc_version@.jar

! ## We have the zip file depend on the java sources and not the class
! ## files, because we don't know the names of all the class files.
! ## FIXME: this method fails in a peculiar case: if libgcj.jar is
! ## up-to-date, and foo.class is removed, and bar.java is touched, then
! ## `make libgcj.jar' will not rebuilt foo.class.  That's because
! ## libgcj.jar is not out-of-date with respect to foo.java.
! libgcj-@gcc_version@.jar: $(built_java_source_files) $(java_source_files) 
$(x_java_source_files)
! ## Create a list of all Java sources, without exceeding any shell limits.
! 	@: $(shell echo Creating list of files to compile...) $(shell rm -f 
tmp-list || :) $(shell touch tmp-list) $(foreach source,$?,$(shell echo 
$(source) >> tmp-list))
! 	@set fnord $(MAKEFLAGS); amf=$$2; fail=no; \
! 	javac="$(JAVAC)"; \
! 	cat tmp-list | (while read f; do \
! 	  echo $$javac $(JCFLAGS) -classpath \'\' -bootclasspath 
$(here):$(srcdir) -d $(here) $$f; \
! 	  $$javac $(JCFLAGS) -classpath '' -bootclasspath $(here):$(srcdir) -d 
$(here) $$f \
! 	    || case "$$amf" in *=*) exit 1;; *k*) fail=yes ;; *) exit 1;; esac; \
! 	done; \
! 	test "$$fail" = no)
! 	-@rm -f tmp-list libgcj-@gcc_version@.jar
  ## Note that we explicitly want to include directory information.
  	find java gnu javax org -type d -o -type f -name '*.class' | \
  	  sed -e '/\/\./d' -e '/\/xlib/d' | \
  	  $(ZIP) cfM0E@ $@

  MOSTLYCLEANFILES = $(javao_files) $(nat_files) $(nat_headers) $(c_files) 
$(x_javao_files) $(x_nat_files) $(x_nat_headers)
! CLEANFILES = tmp-list libgcj-@gcc_version@.jar

  clean-local:
  ## We just remove every .class file that was created.
--- 165,190 ----
  	  $(LN_S) libgcjx.la gnu-awt-xlib.la; \
  	fi

! all_java_source_files = \
!     $(java_source_files) \
!     $(built_java_source_files) \
!     $(x_java_source_files)

! all_java_class_files = $(all_java_source_files:.java=.class)

! $(all_java_class_files): $(all_java_source_files)
!     $(JAVAC) $(JCFLAGS) -classpath '' -bootclasspath $(here):$(srcdir) \
!          -d $(here) $(@:.class=.java)
!
! libgcj-@gcc_version@.jar: $(all_java_class_files)
! 	-@rm -f libgcj-@gcc_version@.jar
  ## Note that we explicitly want to include directory information.
  	find java gnu javax org -type d -o -type f -name '*.class' | \
  	  sed -e '/\/\./d' -e '/\/xlib/d' | \
  	  $(ZIP) cfM0E@ $@

  MOSTLYCLEANFILES = $(javao_files) $(nat_files) $(nat_headers) $(c_files) 
$(x_javao_files) $(x_nat_files) $(x_nat_headers)
! CLEANFILES = libgcj-@gcc_version@.jar

  clean-local:
  ## We just remove every .class file that was created.