[issue10013] fix `./libpython2.6.so: undefined reference to `_PyParser_Grammar´` in parallel builds

[Paul Menzel]

New submission from Paul Menzel <paulepanter at users.sourceforge.net>:

Compiling Python in parallel sometimes fails as reported in [1] and [2].

    ./libpython2.6.so: undefined reference to `_PyParser_Grammar´

Fedora applies a patch by dmalcolm <dmalcolm at fedoraproject.org> which fixes this issue [3].

    diff -up Python-2.7/Makefile.pre.in.fix-parallel-make Python-2.7/Makefile.pre.in
    --- Python-2.7/Makefile.pre.in.fix-parallel-make	2010-07-22 15:01:39.567996932 -0400
    +++ Python-2.7/Makefile.pre.in	2010-07-22 15:47:02.437998509 -0400
    @@ -207,6 +207,7 @@ SIGNAL_OBJS=	@SIGNAL_OBJS@
     
     ##########################################################################
     # Grammar
    +GRAMMAR_STAMP=	$(srcdir)/grammar-stamp
     GRAMMAR_H=	$(srcdir)/Include/graminit.h
     GRAMMAR_C=	$(srcdir)/Python/graminit.c
     GRAMMAR_INPUT=	$(srcdir)/Grammar/Grammar
    @@ -530,10 +531,24 @@ Modules/getpath.o: $(srcdir)/Modules/get
     Modules/python.o: $(srcdir)/Modules/python.c
     	$(MAINCC) -c $(PY_CFLAGS) -o $@ $(srcdir)/Modules/python.c
     
    +# GNU "make" interprets rules with two dependents as two copies of the rule.
    +# 
    +# In a parallel build this can lead to pgen being run twice, once for each of
    +# GRAMMAR_H and GRAMMAR_C, leading to race conditions in which the compiler
    +# reads a partially-overwritten copy of one of these files, leading to syntax
    +# errors (or linker errors if the fragment happens to be syntactically valid C)
    +#
    +# See http://www.gnu.org/software/hello/manual/automake/Multiple-Outputs.html
    +# for more information
    +#
    +# Introduce ".grammar-stamp" as a contrived single output from PGEN to avoid
    +# this:
    +$(GRAMMAR_H) $(GRAMMAR_C): $(GRAMMAR_STAMP)
     
    -$(GRAMMAR_H) $(GRAMMAR_C): $(PGEN) $(GRAMMAR_INPUT)
    +$(GRAMMAR_STAMP): $(PGEN) $(GRAMMAR_INPUT)
     		-@$(INSTALL) -d Include
     		-$(PGEN) $(GRAMMAR_INPUT) $(GRAMMAR_H) $(GRAMMAR_C)
    +		touch $(GRAMMAR_STAMP)
     
     $(PGEN):	$(PGENOBJS)
     		$(CC) $(OPT) $(LDFLAGS) $(PGENOBJS) $(LIBS) -o $(PGEN)

Could you please apply it. Could this also be applied to 2.6.x?


[1] http://doc.services.openoffice.org/wiki/RedTinderboxStatusInEIS
[2] http://www.openoffice.org/issues/show_bug.cgi?id=114866
[3] http://pkgs.fedoraproject.org/gitweb/?p=python.git;a=commit;h=b95f6cc2ca6a009f97436c6aa16cfd70547353d9

----------
components: Build
messages: 117865
nosy: PaulePanter
priority: normal
severity: normal
status: open
title: fix `./libpython2.6.so: undefined reference to `_PyParser_Grammar´` in parallel builds
type: compile error
versions: Python 2.6

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