Re: [ada] Redo Make-lang.in rules to not always regenerategnat_ug_*.texi

[Laurent GUERBY <laurent at guerby dot net>]

On Thu, 2003-12-18 at 16:44, Nathanael Nerode wrote:
> Kelley Cook wrote:
> > Since this hunk was unrelated to the bug that is present in rest of 
> > PR/12744, I am now submitting it broken out for a seperate approval.
> > 
> > On my first attempt to fix PR/12744, Joseph Myers pointed out 
> > (http://gcc.gnu.org/ml/gcc-patches/2003-11/msg00258.html) that both the 
> > fortran77 and the ada directories have generated .texi files which are 
> > required to still be in the CVS directory so a script can easily 
> > generate current webpage documentation without requiring a complete 
> > bootstrap.
> > 
> > However, it soon became obvious to me that the current gnat_ug_*.texi 
> > rules cause them to be always be (identically) regenerated on any build, 
> > since they each depend on the ada/doctools/xgnatug which does not exist 
> > in the source tree, so that file will always be built and will of course 
> > be newer than the .texi file.
> > 
> > Additionally, that executable was also missing a $(buildexe), so the 
> > dependency likely wouldn't quite work under mingw32 or any other 
> > environments which use extensions.
> > 
> > This is a perfect job for order-only dependencies, but unfortunately 
> > that nifty feature didn't yet exist in gnu make 3.79.
> > 
> > So this patch fixes those bugs in the same way the fortran folks did by 
> > punting and introducing a stamp file which contains the real dependency 
> > of the .texi files.  As a bonus ada/doctools/xgnatug($buildexe) will not 
> > be built unless those dependency were touch thereby reducing bootstrap 
> > times by a few seconds.
> > 
> > Bootstrapped numerous times on i686-pc-cygwin as part of testing larger 
> > patch.
> > 
> > OK, assuming regtest with just this hunk passes?
> Yes, OK.

The second bootstrap with the same srcdir and a different builddir
fails, this patch does not look so ok.

make[3]: Leaving directory `/home/guerby/work/gcc/build/build-20031220T133234/gcc'
ada/doctools/xgnatug vms /home/guerby/work/gcc/gcc/gcc/ada/gnat_ug.texi \
 	  /home/guerby/work/gcc/gcc/gcc/ada/ug_words \
  /home/guerby/work/gcc/gcc/gcc/ada/gnat_ug_vms.texi
make[2]: ada/doctools/xgnatug: Command not found
make[2]: *** [/home/guerby/work/gcc/gcc/gcc/ada/gnat_ug_vms.texi] Error 127
make[2]: Leaving directory `/home/guerby/work/gcc/build/build-20031220T133234/gcc'
make[1]: *** [stage1_build] Error 2
make[1]: Leaving directory `/home/guerby/work/gcc/build/build-20031220T133234/gcc'
make: *** [bootstrap] Error 2

srcdir/ada/stamp-xgnatug is present (from first bootstrap) but
builddir/ada/doctools/xgnatug is not rebuilt. If I understand correctly
what is going on, once stamp-xgnatug is present, all subsequent
builds in a clean dir will fail.

Laurent