[pph] Add initial support for including nested pph images (issue4847044)

[gchare@google.com]

So if I understand correctly, the reference system doesn't work yet, you
just put out the design in this patch and you'll fill up functionality
in an upcoming patch so that's it's clearer what you're adding?

Cheers,
Gab


http://codereview.appspot.com/4847044/diff/1/gcc/cp/pph-streamer-in.c
File gcc/cp/pph-streamer-in.c (right):

http://codereview.appspot.com/4847044/diff/1/gcc/cp/pph-streamer-in.c#newcode1491
gcc/cp/pph-streamer-in.c:1491: pph_add_include (stream);
does this mean the included pph has the include information for all of
the headers in it's transitive closure? i.e. we don't need to load child
information of a child? if so, isn't this bad from a dependency point of
view?

http://codereview.appspot.com/4847044/diff/1/gcc/cp/pph.c
File gcc/cp/pph.c (right):

http://codereview.appspot.com/4847044/diff/1/gcc/cp/pph.c#newcode164
gcc/cp/pph.c:164: if (pph_out_file != NULL)
shouldn't you use your new pph_enabled_p function here?

http://codereview.appspot.com/4847044/diff/1/gcc/testsuite/g++.dg/pph/c1pr44948-1a.cc
File gcc/testsuite/g++.dg/pph/c1pr44948-1a.cc (right):

http://codereview.appspot.com/4847044/diff/1/gcc/testsuite/g++.dg/pph/c1pr44948-1a.cc#newcode1
gcc/testsuite/g++.dg/pph/c1pr44948-1a.cc:1: /* { dg-options "-O
-Wno-psabi -mtune=generic" } */
Is this related to the rest of the changes in this patch? I don't see it
mentioned in your patch comments

http://codereview.appspot.com/4847044/