[Mesa-dev] [PATCH] genxml: avoid using a GNU make pattern rule

[Jonathan Gray]

On Mon, May 02, 2016 at 11:44:35AM -0700, Jason Ekstrand wrote:
> On Mon, May 2, 2016 at 2:27 AM, Jonathan Gray <jsg at jsg.id.au> wrote:
> 
> > On Mon, May 02, 2016 at 02:23:46AM -0700, Jason Ekstrand wrote:
> > > On May 1, 2016 11:24 PM, "Jonathan Gray" <jsg at jsg.id.au> wrote:
> > > >
> > > > % pattern rules are a GNU extension.  Convert the use of one to a
> > > > suffix rule to allow this to build on OpenBSD.
> > > >
> > > > Signed-off-by: Jonathan Gray <jsg at jsg.id.au>
> > > > ---
> > > >  src/intel/genxml/Makefile.am | 4 +++-
> > > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/src/intel/genxml/Makefile.am
> > b/src/intel/genxml/Makefile.am
> > > > index f493d48..ea68fb9 100644
> > > > --- a/src/intel/genxml/Makefile.am
> > > > +++ b/src/intel/genxml/Makefile.am
> > > > @@ -28,7 +28,9 @@ BUILT_SOURCES =
> > >  \
> > > >
> > > >  PYTHON3_GEN = $(AM_V_GEN)$(PYTHON3) $(PYTHON_FLAGS)
> > > >
> > > > -%_pack.h : %.xml gen_pack_header.py
> > > > +SUFFIXES = _pack.h .xml
> > > > +
> > > > +.xml_pack.h : gen_pack_header.py
> > > >         $(PYTHON3_GEN) $(srcdir)/gen_pack_header.py $< > $@
> > >
> > > We'd better also fix up all the places we include these files. :-)
> >
> > The generated filenames don't change, there is no need to:
> >
> 
> I just read up on Suffix rules (didn't even know they existed).  I think
> what you're doing there *mostly* works.  The problem is that, according to
> the GNU make docs (
> https://www.gnu.org/software/make/manual/html_node/Suffix-Rules.html),
> suffix rules aren't allowed to have any additional prerequisites declared.
> If they do, they get treated as normal non-suffix rules.  How do we do this
> as a suffix rule *and* have it depend on both genN.xml and
> gen_pack_header.py?
> --jason

The docs on OpenBSD suggest adding another target rule for this case
which seems to work as intended here.

see "INFERENCE RULES" in
http://man.openbsd.org/OpenBSD-current/man1/make.1

commit 715e29f2a1db62f69a92e742cd33fc75889367ff
Author: Jonathan Gray <jsg at jsg.id.au>
Date:   Mon May 2 16:14:56 2016 +1000

    genxml: avoid using a GNU make pattern rule
    
    % pattern rules are a GNU extension.  Convert the use of one to a
    inference rule to allow this to build on OpenBSD.
    
    v2: inference rules can't have additional prerequisites
    so add a target rule to still depend on gen_pack_header.py
    
    Signed-off-by: Jonathan Gray <jsg at jsg.id.au>

diff --git a/src/intel/genxml/Makefile.am b/src/intel/genxml/Makefile.am
index f493d48..0b5b3a6 100644
--- a/src/intel/genxml/Makefile.am
+++ b/src/intel/genxml/Makefile.am
@@ -28,7 +28,11 @@ BUILT_SOURCES =                                         \
 
 PYTHON3_GEN = $(AM_V_GEN)$(PYTHON3) $(PYTHON_FLAGS)
 
-%_pack.h : %.xml gen_pack_header.py
+SUFFIXES = _pack.h .xml
+
+$(BUILT_SOURCES): gen_pack_header.py
+
+.xml_pack.h:
 	$(PYTHON3_GEN) $(srcdir)/gen_pack_header.py $< > $@
 
 CLEANFILES = $(BUILT_SOURCES)