Hi all!
I have some trouble building a yacc parser with Automake (using
ylwrap) in a parallel build. Usually, make -j runs fine on my project
with no errors, but it fails occasionally when trying to build the
parser. Here is a stripped down test case that demonstrates what I'm
doing (using Autoconf 2.63, Automake 1.10.2):
===============
configure.ac:
---------------
AC_PREREQ([2.63])
AC_INIT([testing],[0.1],[d...@not.exist])
AM_INIT_AUTOMAKE([-Wall foreign])
AC_CONFIG_SRCDIR([parser.y])
AC_CONFIG_HEADERS([config.h])
AC_PROG_CC
AM_PROG_LEX
AC_PROG_YACC
AC_PROG_RANLIB
YFLAGS="${YFLAGS} -d"
AC_CONFIG_FILES([Makefile])
AC_OUTPUT
===============
===============
Makefile.am:
---------------
noinst_LIBRARIES=libparser.a
libparser_a_SOURCES=parser.y scanner.l
===============
===============
parser.y
---------------
%{
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /* HAVE_CONFIG_H */
int yylex (void);
void yyerror (char const *);
%}
%token NUM
%token STRING
%token OP
%%
input: NUM
;
===============
===============
scanner.l
---------------
%{
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /* HAVE_CONFIG_H */
#include <stdio.h>
#include "parser.h"
%}
%%
[0-9]+ return NUM;
%%
int yyerror(const char *err) { fprintf(stderr,"Error.\n"); return -1;
}
===============
With only these four files in some directory, execute the following
commands:
$ autoreconf -i
configure.ac:3: installing `./install-sh'
configure.ac:3: installing `./missing'
Makefile.am: installing `./depcomp'
configure.ac: installing `./ylwrap'
$ ./configure
...
$ STOP=0; while test $STOP -eq 0; do make clean && rm -f parser.[ch] scanner.c
&& make -j || STOP=1; done
The last line cleans up the project and performs a parallel build
again and again until it fails -- and it does fail after a couple of
runs, sometimes straight after the first one, sometimes after 10 or
even more, like this:
[...]
/bin/bash ./ylwrap parser.y y.tab.c parser.c y.tab.h parser.h y.output
parser.output -- bison -y -d
/bin/bash ./ylwrap scanner.l lex.yy.c scanner.c -- flex
gcc -DHAVE_CONFIG_H -I. -g -O2 -MT scanner.o -MD -MP -MF .deps/scanner.Tpo
-c -o scanner.o scanner.c
scanner.l:6:20: error: parser.h: No such file or directory
updating parser.h
gcc -DHAVE_CONFIG_H -I. -g -O2 -MT parser.o -MD -MP -MF .deps/parser.Tpo -c
-o parser.o parser.c
scanner.l: In function `yylex':
scanner.l:9: error: `NUM' undeclared (first use in this function)
scanner.l:9: error: (Each undeclared identifier is reported only once
scanner.l:9: error: for each function it appears in.)
make[1]: *** [scanner.o] Error 1
[...]
The file parser.h should have been generated by ylwrap/bison before
compiling scanner.c, but apparently this is not always the case.
I can reproduce this on Linux/amd64 (Ubuntu 8.10, dual core) and on
Solaris 10/i386 (dual core), using GNU Make 3.81 on both machines. The
problem seems to go away, however, when using pmake -j 4 (NetBSD make)
on my Linux machine.
Now, did I forget to add some additional rules to Makefile.am? Or do
you think I have hit a bug in ylwrap or in GNU Make?
Best regards,
Robert Homann
--
Windows is not the answer.
Windows is the question.
The answer is "No".
