Re: [PATCH] Makefile fix

[Doug Evans <xdje42 at gmail dot com>]

On Sat, Feb 8, 2014 at 3:41 AM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
>> Date: Fri, 7 Feb 2014 21:00:35 -0800
>> From: Doug Evans <dje@google.com>
>>
>> On Tue, Feb 4, 2014 at 2:33 AM, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
>> > The diff below fixes an issue that has been bothering me for quite a
>> > while.  When using OpenBSD make, almost everything in gdb/ gets
>> > rebuilt.  The problem is the use of the all-lib phony target, which is
>> > always considered to be out-of-date, and used as a prerequisite of
>> > libgnu.a and the gnulib string.h, which are therefore also considered
>> > to be out-of-date.  I have no idea why this problem doesn't show up
>> > with GNU make.  But the GNU make manual clearly states that phony
>> > targets should not be prerequisites of real target files:
>> >
>> >   <http://www.gnu.org/software/make/manual/make.html#Phony-Targets>
>> >
>> > It seems to me that the phony target can be easily avoided; see the
>> > diff below.  But perhaps I'm missing something?
>> >
>> >
>> >
>> > diff --git a/gdb/Makefile.in b/gdb/Makefile.in
>> > index ed84e35..937478b 100644
>> > --- a/gdb/Makefile.in
>> > +++ b/gdb/Makefile.in
>> > @@ -1263,10 +1263,8 @@ gdb$(EXEEXT): gdb.o $(LIBGDB_OBS) $(ADD_DEPS) $(CDEPS) $(TDEPLIBS)
>> >                 $(TDEPLIBS) $(TUI_LIBRARY) $(CLIBS) $(LOADLIBES)
>> >
>> >  # Convenience rule to handle recursion.
>> > -$(LIBGNU) $(GNULIB_H): all-lib
>> > -all-lib: $(GNULIB_BUILDDIR)/Makefile
>> > +$(LIBGNU) $(GNULIB_H): $(GNULIB_BUILDDIR)/Makefile
>> >         @$(MAKE) $(FLAGS_TO_PASS) DO=all DODIRS=$(GNULIB_BUILDDIR) subdir_do
>> > -.PHONY: all-lib
>> >
>> >  # Convenience rule to handle recursion.
>> >  .PHONY: all-data-directory
>>
>> I found the patch where this went in but I couldn't find anything interesting.
>> "all-lib" is there, I'm guessing, just as a convenience for typing,
>> but I'm not sure how often it's used so if it's getting in the way I'm
>> ok with this change.
>> I can't think of any problems with the patch.
>> [And we could still keep all-lib as a convenience rule, but I'm ok
>> with deleting it for now.]
>
> Thanks.  Here's what I committed:
>
> From 0a6bd22df74bb5b6ffa30c3b10243a34d9055c32 Mon Sep 17 00:00:00 2001
> From: Mark Kettenis <kettenis@gnu.org>
> Date: Sat, 8 Feb 2014 12:36:17 +0100
> Subject: [PATCH] A phony target should not be a prerequisite of a real target
>  file
>
> gdb/ChangeLog:
>
>         * Makefile.in (all-lib): Remove.
>         ($(LIBGNU) $(GNULIB_H)): Replace with gits of remove all-lib target.
> ---
>  gdb/ChangeLog   | 5 +++++
>  gdb/Makefile.in | 4 +---
>  2 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
> index c2c9236..bb64a23 100644
> --- a/gdb/ChangeLog
> +++ b/gdb/ChangeLog
> @@ -1,3 +1,8 @@
> +2014-02-08  Mark Kettenis  <kettenis@gnu.org>
> +
> +       * Makefile.in (all-lib): Remove.
> +       ($(LIBGNU) $(GNULIB_H)): Replace with gits of remove all-lib target.
> +
>  2014-02-07  Doug Evans  <dje@google.com>
>
>         * extension-priv.h (extension_language_script_ops): Add comment.
> diff --git a/gdb/Makefile.in b/gdb/Makefile.in
> index e714550..0976615 100644
> --- a/gdb/Makefile.in
> +++ b/gdb/Makefile.in
> @@ -1265,10 +1265,8 @@ gdb$(EXEEXT): gdb.o $(LIBGDB_OBS) $(ADD_DEPS) $(CDEPS) $(TDEPLIBS)
>                 $(TDEPLIBS) $(TUI_LIBRARY) $(CLIBS) $(LOADLIBES)
>
>  # Convenience rule to handle recursion.
> -$(LIBGNU) $(GNULIB_H): all-lib
> -all-lib: $(GNULIB_BUILDDIR)/Makefile
> +$(LIBGNU) $(GNULIB_H): $(GNULIB_BUILDDIR)/Makefile
>         @$(MAKE) $(FLAGS_TO_PASS) DO=all DODIRS=$(GNULIB_BUILDDIR) subdir_do
> -.PHONY: all-lib
>
>  # Convenience rule to handle recursion.
>  .PHONY: all-data-directory
> --
> 1.8.5.3
>

I'm getting gnulib related build failures on linux, I'm guessing it's
this change.
Sorry 'bout that.
I think it's that a parallel make is now entering build-gnulib twice.
So we need to serialize it, without using a phony target.