Xapian devel - Jan 2009 - Xapian core build failure under gcc 2.95

Hi,


Under gcc 2.95 Xapian fails to build like so:

 g++ -DHAVE_CONFIG_H -I. -I./common -I./include 
-I/home/dsainty/not-backed-up/pkgsrc/textproc/xapian/work/.buildlink/include 
-Wall -W -Wredundant-decls -Wpointer-arith -Wcast-qual -Wcast-align 
-Wno-long-long -Wformat-security -fno-gnu-keywords -Wundef -O2 -c 
queryparser/queryparser_internal.cc 
-Wp,-MD,queryparser/.deps/queryparser_internal.TPlo  -fPIC -DPIC -o 
queryparser/.libs/queryparser_internal.o
/data/home/olly/tmp/xapian-svn-snapshot/tags/1.0.10/xapian/xapian-core/queryparser/queryparser.lemony:25:
queryparser_internal.h: No such file or directory
/data/home/olly/tmp/xapian-svn-snapshot/tags/1.0.10/xapian/xapian-core/queryparser/queryparser.lemony:31:
queryparser_token.h: No such file or directory
*** Error code 1

The problem seems to be that the build system is relying on the compiler 
to imply -Iqueryparser when the source file is 
queryparser/queryparser_internal.cc.  Modern gcc makes this implication, 
gcc 2.95 doesn't.

queryparser/Makefile.mk has an almost-solution there already, but it's 
conditionally disabled.

  if VPATH_BUILD
  # We need this so that generated sources can find non-generated 
headers in a
  # VPATH build from SVN.
  INCLUDES += -I$(top_srcdir)/queryparser

  if MAINTAINER_MODE
  # We need this because otherwise, if depcomp is being used (as it will 
be for a
  # build with gcc-2.95), depcomp will be unable to find 
queryparser_token.h.
  # This may be a bug in depcomp, but it certainly happens with 
automake-1.10.
  INCLUDES += -I$(top_builddir)/queryparser
  endif
  endif

If instead it unconditionally set: INCLUDES += -I$(top_builddir)/queryparser

... regardless of flags, that should fix the build on old GCC and 
perhaps some other non-GCC compilers, and would make it clearer what is 
happening for those people like me that still find the newer GCC 
behaviour a little odd :)

(Please CC: email, I'm not on the list)

Cheers,

Dave

David Sainty wrote:
> Hi,
>
> Under gcc 2.95 Xapian fails to build like so:
I can confirm that the attached patch fixes the build under gcc 2.95 
(after an automake).

Cheers,

Dave
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: xapian-gcc-295
URL:
<http://lists.xapian.org/pipermail/xapian-devel/attachments/20090115/cbdc4c91/attachment.ksh>

On Thu, Jan 15, 2009 at 04:53:52PM +1300, David Sainty
wrote:
> David Sainty wrote:
> >Under gcc 2.95 Xapian fails to build like so:
> 
> I can confirm that the attached patch fixes the build under gcc 2.95 
> (after an automake).
Thanks for the patch.

But it seems there's something odd going on, as other subdirectories
also include headers from the same directory without an explicit -I.
The files here are generated, but that shouldn't make a difference as
they are shipped in the tarball and it appears you're building from the
1.0.10 source tarball.

Perhaps the issue is the "#line" directives with full paths in
queryparser_internal.cc - if GCC 2.95 resolves header includes relative
to the filename given by "#line" then that would cause this problem.

Could you try:

perl -pi -e 's/^#line.*//' queryparser/queryparser_internal.cc

And then building without your patch.

(Unfortunately I no longer have access to GCC 2.95 to test this myself).

Another question - what's the reason for using GCC 2.95?

We came quite closing to dropping support for GCC < 3 a while back (but
instead we ended up requiring 2.95.3 which added <sstream>).  But I'd
assumed that 2.95 was probably no longer used by now, and there are a
few minor issues we currently work around to keep support for it, so if
there are still people using it I'm interested as to why.

Cheers,
    Olly