[docs] bootstrapping guide

docs/bootstrapping.pod

@@ -0,0 +1,48 @@
+=head1 Bootstrapping procedure for nqp-rx
+
+NPQ-rx is a bootstrapped compiler, which means that it uses itself to compile
+itself.
+
+To make the first compilation possible, a compiled version of the compiler is
+stored in F</src/stage0/*.pir> and included in the source code repository.
+Also the parrot virtual machine ships the same
+C<stage0/*.pir> files.
+
+When you make changes to the compiler, eventually you need to update these
+I<stage0> files.
+
+Here is how you proceed to update the bootstrapping files nqp-rx and parrot.
+At any stage, if C<make test> fails, don't go ahead with the following steps,
+but fix the problem first.
+
+=over
+
+=item *
+
+Make your changes, run C<make test>
+
+=item *
+
+Run C<make bootstrap-files> and C<make test>
+
+=item *
+
+Commit the non-bootstrap files that you modified yourself
+
+=item *
+
+Commit the bootstrap files
+
+=item *
+
+Copy the I<stage0> files over to parrot:
+
+    cp src/stage0/*.pir $PARROT_SRC/ext/nqp/src/stage0
+
+=item *
+
+In the parrot source, run C<make test> and commit
+
+=back
+
+References: L<http://irclog.perlgeek.de/perl6/2010-04-22#i_2253227>