2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief SSA construction for a set of nodes
23 * @author Sebastian Hack, Daniel Grund, Matthias Braun, Christian Wuerdig
26 * The problem: Given a value and a set of "copies" that are known to
27 * represent the same abstract value, rewire all usages of the original value
28 * to their closest copy while introducing phis as necessary.
30 * Algorithm: Mark all blocks in the iterated dominance frontiers of the value
31 * and its copies. Link the copies ordered by dominance to the blocks. Then
32 * we search for each use all definitions in the current block, if none is
33 * found, then we search one in the immediate dominator. If we are in a block
34 * of the dominance frontier, create a phi and do the same search for all
37 * A copy in this context means, that you want to introduce several new
38 * abstract values (in Firm: nodes) for which you know, that they
39 * represent the same concrete value. This is the case if you
45 * This function reroutes all uses of the original value to the copies in the
46 * corresponding dominance subtrees and creates Phi functions where necessary.
48 #ifndef FIRM_BE_BESSACONSTR_H
49 #define FIRM_BE_BESSACONSTR_H
52 #include "firm_types.h"
53 #include "irnodeset.h"
58 #include "irnodemap.h"
61 typedef struct be_ssa_construction_env_t {
64 const arch_register_req_t *phi_req;
66 const ir_nodeset_t *ignore_uses;
68 bool iterated_domfront_calculated;
71 } be_ssa_construction_env_t;
74 * Initializes an SSA construction environment.
76 * @param env an empty SSA construction environment
77 * @param irg the graph
79 void be_ssa_construction_init(be_ssa_construction_env_t *env, ir_graph *irg);
81 void be_ssa_construction_add_copy(be_ssa_construction_env_t *env,
84 void be_ssa_construction_add_copies(be_ssa_construction_env_t *env,
85 ir_node **copies, size_t copies_len);
87 void be_ssa_construction_set_ignore_uses(be_ssa_construction_env_t *env,
88 const ir_nodeset_t *ignore_uses);
91 * Reconstructs the SSA form for all users of node @p node
93 void be_ssa_construction_fix_users(be_ssa_construction_env_t *env,
96 void be_ssa_construction_fix_users_array(be_ssa_construction_env_t *env,
97 ir_node **nodes, size_t nodes_len);
100 * Recompute the liveness of the inserted phis.
101 * @note Remember that you have to call update_liveness on the copies yourself
103 void be_ssa_construction_update_liveness_phis(be_ssa_construction_env_t *env,
106 ir_node **be_ssa_construction_get_new_phis(be_ssa_construction_env_t *env);
109 * Destroys an SSA construction environment.
111 void be_ssa_construction_destroy(be_ssa_construction_env_t *env);
113 #endif /* FIRM_BE_BESSACONSTR_H */