* lto-streamer-out.c (struct sccs): Turn to ...

	* lto-streamer-out.c (struct sccs): Turn to ...
	(class DFS): ... this one; refactor the DFS walk so it can
	be re-done on per-SCC basis.
	(DFS::DFS): New constructor.
	(DFS::~DFS): New destructor.
	(hash_tree): Add new MAP argument holding in-SCC hash values;
	remove POINTER_TYPE hashing hack.
	(scc_entry_compare): Rename to ...
	(DFS::scc_entry_compare): ... this one.
	(hash_scc): Rename to ...
	(DFS::hash_scc): ... this one; pass output_block instead
	of streamer_cache; work harder to get unique and stable SCC
	hashes.
	(DFS_write_tree): Rename to ...
	(DFS::DFS_write_tree): ... this one; add SINGLE_P parameter.
	(lto_output_tree): Update.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@213059 138bc75d-0d04-0410-961f-82ee72b054a4