+/**
+ * @file
+ * @author Sebastian Hack, Daniel Grund
+ * @date: 04.05.2005
+ * @version $Id$
+ * Copyright: (c) Universitaet Karlsruhe
+ * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
+ */
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "bedomfront.h"
+
+#include "obst.h"
+#include "pmap.h"
+#include "pdeq.h"
+#include "irdom.h"
+#include "array.h"
+#include "irgraph.h"
+#include "iredges_t.h"
+
+/**
+ * The dominance frontier for a graph.
+ */
+struct _be_dom_front_info_t {
+ pmap *df_map; /**< A map, mapping every block to a list of its dominance frontier blocks. */
+ struct obstack obst; /**< An obstack holding all the frontier data. */
+};
+
+/**
+ * A wrapper for get_Block_idom.
+ * This function returns the block itself, if the block is the start
+ * block. Returning NULL would make any != comparison true which
+ * suggests, that the start block is dominated by some other node.
+ * @param bl The block.
+ * @return The immediate dominator of the block.
+ */
+static INLINE
+ir_node *get_idom(ir_node *bl)
+{
+ ir_node *idom = get_Block_idom(bl);
+ return idom == NULL ? bl : idom;
+}
+
+/**
+ * Compute the dominance frontier for a given block.
+ *
+ * @param blk the block where the calculation starts
+ *
+ * @return the list of all blocks in the dominance frontier of blk
+ */
+static
+ir_node **compute_df(ir_node *blk, be_dom_front_info_t *info)
+{
+ ir_node *c;
+ const ir_edge_t *edge;
+ ir_node **df_list = NEW_ARR_F(ir_node *, 0);
+ ir_node **df;
+ int len;
+
+ /* Add local dominance frontiers */
+ foreach_block_succ(blk, edge) {
+ ir_node *y = get_edge_src_irn(edge);
+
+ if (get_idom(y) != blk) {
+ ARR_APP1(ir_node *, df_list, y);
+ }
+ }
+
+ /*
+ * Go recursively down the dominance tree and add all blocks
+ * into the dominance frontiers of the children, which are not
+ * dominated by the given block.
+ */
+ for (c = get_Block_dominated_first(blk); c; c = get_Block_dominated_next(c)) {
+ int i;
+ ir_node **df_c_list = compute_df(c, info);
+
+ for (i = ARR_LEN(df_c_list) - 1; i >= 0; --i) {
+ ir_node *w = df_c_list[i];
+ if (get_idom(w) != blk)
+ ARR_APP1(ir_node *, df_list, w);
+ }
+ }
+
+ /* now copy the flexible array to the obstack */
+ len = ARR_LEN(df_list);
+ df = NEW_ARR_D(ir_node *, &info->obst, len);
+ memcpy(df, df_list, len * sizeof(df[0]));
+ DEL_ARR_F(df_list);
+
+ pmap_insert(info->df_map, blk, df);
+ return df;
+}
+
+be_dom_front_info_t *be_compute_dominance_frontiers(ir_graph *irg)
+{
+ be_dom_front_info_t *info = xmalloc(sizeof(*info));
+
+ edges_assure(irg);
+ obstack_init(&info->obst);
+ info->df_map = pmap_create();
+ assure_doms(irg);
+ (void)compute_df(get_irg_start_block(irg), info);
+
+ return info;
+}
+
+void be_free_dominance_frontiers(be_dom_front_info_t *info)
+{
+ obstack_free(&info->obst, NULL);
+ pmap_destroy(info->df_map);
+ free(info);
+}
+
+/* Get the dominance frontier of a block. */
+ir_node **be_get_dominance_frontier(const be_dom_front_info_t *info,
+ ir_node *block)
+{
+ return pmap_get(info->df_map, block);
+}
+
+/**
+ * Calculates the iterated dominance frontier of a set of blocks.
+ * Also clears the link field of the returned blocks as a side effect
+ */
+void be_get_iterated_dominance_frontiers(const be_dom_front_info_t *domfronts,
+ ir_nodeset_t *blocks)
+{
+ ir_node *block;
+ ir_nodeset_iterator_t iter;
+ waitq *worklist = new_waitq();
+
+ foreach_ir_nodeset(blocks, block, iter) {
+ waitq_put(worklist, block);
+ }
+
+ while(!pdeq_empty(worklist)) {
+ int i;
+ ir_node *block = waitq_get(worklist);
+ ir_node **domfront = be_get_dominance_frontier(domfronts, block);
+ int domfront_len = ARR_LEN(domfront);
+
+ for (i = 0; i < domfront_len; ++i) {
+ ir_node *y = domfront[i];
+ if(!ir_nodeset_insert(blocks, y))
+ continue;
+
+ waitq_put(worklist, y);
+ }
+ }
+
+ del_waitq(worklist);
+}