X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fbe%2Fbessaconstr.h;h=ab08c76e8ba783668892c265c8c487813fd90eea;hb=c1fdf770d4d000dd5cf22daead32369342c5f5d1;hp=d92640493e575f559dceb0aecc844cfb789aa128;hpb=4d5c3365a58cba59993045a9e08e686d8ae079a7;p=libfirm

diff --git a/ir/be/bessaconstr.h b/ir/be/bessaconstr.h
index d92640493..ab08c76e8 100644
--- a/ir/be/bessaconstr.h
+++ b/ir/be/bessaconstr.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
+ * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
  *
  * This file is part of libFirm.
  *
@@ -19,13 +19,22 @@
 
 /**
  * @file
- * @brief     Introduce several copies for one node.
- * @author    Sebastian Hack, Daniel Grund, Matthias Braun, Christian Wuerdig
- * @date      30.03.2007
- * @version   $Id$
- * Copyright: (c) Universitaet Karlsruhe
- * Licence:   This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
-
+ * @brief       SSA construction for a set of nodes
+ * @author      Sebastian Hack, Daniel Grund, Matthias Braun, Christian Wuerdig
+ * @date        30.03.2007
+ * @version     $Id$
+ *
+ * The problem: Given a value and a set of "copies" that are known to
+ * represent the same abstract value, rewire all usages of the original value
+ * to their closest copy while introducing phis as necessary.
+ *
+ * Algorithm: Mark all blocks in the iterated dominance frontiers of the value
+ * and it's copies. Link the copies ordered by dominance to the blocks.  Then
+ * we search for each use all definitions in the current block, if none is
+ * found, then we search one in the immediate dominator. If we are in a block
+ * of the dominance frontier, create a phi and do the same search for all
+ * phi arguments.
+ *
  * A copy in this context means, that you want to introduce several new
  * abstract values (in Firm: nodes) for which you know, that they
  * represent the same concrete value. This is the case if you
@@ -37,29 +46,32 @@
  * This function reroutes all uses of the original value to the copies in the
  * corresponding dominance subtrees and creates Phi functions where necessary.
  */
-#ifndef FIRM_BE_SSACONSTR_H
-#define FIRM_BE_SSACONSTR_H
+#ifndef FIRM_BE_BESSACONSTR_H
+#define FIRM_BE_BESSACONSTR_H
 
-#include <stdlib.h>
+#include "firm_types.h"
 #include "bedomfront.h"
-#include "irnode.h"
 #include "irnodeset.h"
 #include "belive.h"
+#include "bitset.h"
 #include "beirg.h"
 #include "pdeq.h"
 
 typedef struct be_ssa_construction_env_t {
-	ir_graph                   *irg;
-	const be_dom_front_info_t  *domfronts;
-	ir_mode                    *mode;
-	waitq                      *worklist;
-	const ir_nodeset_t         *ignore_uses;
+	ir_graph                  *irg;
+	const be_dom_front_info_t *domfronts;
+	ir_mode                   *mode;
+	waitq                     *worklist;
+	const ir_nodeset_t        *ignore_uses;
 	ir_node                   **new_phis;
-	int                         iterated_domfront_calculated;
+	int                       iterated_domfront_calculated;
 } be_ssa_construction_env_t;
 
 /**
- * Initializes an ssa construction environment.
+ * Initializes an SSA construction environment.
+ *
+ * @param env    an SSA empty construction environment
+ * @param birg
  */
 void be_ssa_construction_init(be_ssa_construction_env_t *env, be_irg_t *birg);
 
@@ -95,4 +107,4 @@ ir_node **be_ssa_construction_get_new_phis(be_ssa_construction_env_t *env);
  */
 void be_ssa_construction_destroy(be_ssa_construction_env_t *env);
 
-#endif
+#endif /* FIRM_BE_BESSACONSTR_H */