Hi! As reported by Matthias, --enable-link-serialization=1 can currently start two concurrent links first (e.g. gnat1 and cc1). The problem is that make var = value values seem to work differently between dependencies and actual rules (where it was tested). As the language make fragments can be in different order, we can have: # Part of Makefile added by configure ada.prev = ... magic that will become $(c.serial) under --enable-link-serialization=1 # ada/gcc-interface/Make-lang.in gnat1$(exe): ..... $(ada.prev) ... # c/Make-lang.in c.serial = cc1$(exe) and while if I add echo $(ada.prev) in the gnat1 rule's command, it prints cc1, the dependencies are actually evaluated during reading of the goal or when. The configure creates (and puts into Makefile) some serialization order of the languages and in that order c always comes first, and the rest is actually sorted the way the all_lang_makefrags are already sorted, so just by forcing c/Make-lang.in first we achieve that X.serial variable is always defined before some other Y.prev will use it in its goal dependencies.
Bootstrapped/regtested on x86_64-linux and i686-linux, without --enable-link-serialization altogether, with =1 and with =3, all results look good. Ok for trunk? 2021-01-12 Jakub Jelinek <ja...@redhat.com> * configure.ac: Ensure c/Make-lang.in comes first in @all_lang_makefrags@. * configure: Regenerated. --- gcc/configure.ac.jj 2021-01-05 13:57:59.911905006 +0100 +++ gcc/configure.ac 2021-01-11 14:49:22.878218318 +0100 @@ -6975,7 +6975,12 @@ changequote([,])dnl $ok || continue all_lang_configurefrags="$all_lang_configurefrags \$(srcdir)/$gcc_subdir/config-lang.in" - all_lang_makefrags="$all_lang_makefrags \$(srcdir)/$gcc_subdir/Make-lang.in" + if test "x$language" = xc && test -n "$all_lang_makefrags"; then + # Put c/Make-lang.in fragment first to match serialization languages order. + all_lang_makefrags="\$(srcdir)/$gcc_subdir/Make-lang.in $all_lang_makefrags" + else + all_lang_makefrags="$all_lang_makefrags \$(srcdir)/$gcc_subdir/Make-lang.in" + fi if test -f $srcdir/$gcc_subdir/lang.opt; then lang_opt_files="$lang_opt_files $srcdir/$gcc_subdir/lang.opt" all_opt_files="$all_opt_files $srcdir/$gcc_subdir/lang.opt" --- gcc/configure.jj 2021-01-06 22:17:07.275967932 +0100 +++ gcc/configure 2021-01-11 14:49:29.708140555 +0100 @@ -31174,7 +31174,12 @@ do $ok || continue all_lang_configurefrags="$all_lang_configurefrags \$(srcdir)/$gcc_subdir/config-lang.in" - all_lang_makefrags="$all_lang_makefrags \$(srcdir)/$gcc_subdir/Make-lang.in" + if test "x$language" = xc && test -n "$all_lang_makefrags"; then + # Put c/Make-lang.in fragment first to match serialization languages order. + all_lang_makefrags="\$(srcdir)/$gcc_subdir/Make-lang.in $all_lang_makefrags" + else + all_lang_makefrags="$all_lang_makefrags \$(srcdir)/$gcc_subdir/Make-lang.in" + fi if test -f $srcdir/$gcc_subdir/lang.opt; then lang_opt_files="$lang_opt_files $srcdir/$gcc_subdir/lang.opt" all_opt_files="$all_opt_files $srcdir/$gcc_subdir/lang.opt" Jakub