2009-10-14  Richard Guenther  <rguenther@suse.de>

	* lto-symtab.c (lto_symtab_compatible): Fold in ...
	(lto_symtab_merge): ... here.  Rewrite both to take the
	prevailing and a to-be-merged entry and to queue diagnostics
	properly.
	(lto_symtab_resolve_replaceable_p): New predicate for
	symbol resolution.
	(lto_symtab_resolve_can_prevail_p): Likewise.
	(lto_symtab_resolve_symbols): Rewrite.  Fold in code that
	handles merging commons by choosing the largest decl.  Fold
	in code that gives ODR errors.
	(lto_symtab_merge_decls_2): Simplify a lot.  Emit queued
	diagnostics here.
	(lto_symtab_merge_decls_1): Re-structure.  Deal with the
	case of no prevailing decl here.  Diagnose mismatches
	in object types here.  Drop all but the prevailing decls.
	(lto_symtab_prevailing_decl): Return the single prevailing decl.
	* lto-streamer-in.c (lto_input_tree_ref): Deal with
	VIEW_CONVERT_EXPRs in decl slots.  Unshare the tree in this case.

	lto/
	* lto.c (lto_fixup_tree): In case the prevailing decl is not
	compatible with the one we replace wrap it around a
	VIEW_CONVERT_EXPR.

From-SVN: r152768