nsz Git - libfirm/blob - ir/be/beirgmod.c

   1 /*
   2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   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.
  10  *
  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.
  14  *
  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
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief       Backend IRG modification routines.
  23  * @author      Sebastian Hack, Daniel Grund, Matthias Braun, Christian Wuerdig
  24  * @date        04.05.2005
  25  * @version     $Id$
  26  *
  27  * This file contains the following IRG modifications for be routines:
  28  * - insertion of Perm nodes
  29  * - empty block elimination
  30  * - a simple dead node elimination (set inputs of unreachable nodes to BAD)
  31  */
  32 #include "config.h"
  33
  34 #include <stdlib.h>
  35
  36 #include "hashptr.h"
  37 #include "pdeq.h"
  38 #include "pset.h"
  39 #include "pmap.h"
  40 #include "util.h"
  41 #include "debug.h"
  42 #include "error.h"
  43 #include "xmalloc.h"
  44
  45 #include "irflag_t.h"
  46 #include "ircons_t.h"
  47 #include "irnode_t.h"
  48 #include "ircons_t.h"
  49 #include "irmode_t.h"
  50 #include "irdom_t.h"
  51 #include "iredges_t.h"
  52 #include "irgraph_t.h"
  53 #include "irgopt.h"
  54 #include "irgmod.h"
  55 #include "irprintf_t.h"
  56 #include "irgwalk.h"
  57
  58 #include "be_t.h"
  59 #include "bechordal_t.h"
  60 #include "bearch.h"
  61 #include "besched.h"
  62 #include "belive_t.h"
  63 #include "benode.h"
  64 #include "beutil.h"
  65 #include "beinsn_t.h"
  66 #include "bessaconstr.h"
  67 #include "beirg.h"
  68 #include "beirgmod.h"
  69 #include "bemodule.h"
  70
  71 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  72
  73 /*
  74   ___                     _     ____
  75  |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___ _ __ _ __ ___
  76   | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ '__| '_ ` _ \
  77   | || | | \__ \  __/ |  | |_  |  __/  __/ |  | | | | | |
  78  |___|_| |_|___/\___|_|   \__| |_|   \___|_|  |_| |_| |_|
  79
  80 */
  81
  82 ir_node *insert_Perm_after(be_irg_t *birg,
  83                                                    const arch_register_class_t *cls,
  84                                                    ir_node *pos)
  85 {
  86         be_lv_t *lv     = birg->lv;
  87         ir_node *bl     = is_Block(pos) ? pos : get_nodes_block(pos);
  88         ir_nodeset_t          live;
  89         ir_nodeset_iterator_t iter;
  90
  91         ir_node *curr, *irn, *perm, **nodes;
  92         size_t i, n;
  93
  94         DBG((dbg, LEVEL_1, "Insert Perm after: %+F\n", pos));
  95
  96         ir_nodeset_init(&live);
  97         be_liveness_nodes_live_at(lv, cls, pos, &live);
  98
  99         n = ir_nodeset_size(&live);
 100         if (n == 0) {
 101                 ir_nodeset_destroy(&live);
 102                 return NULL;
 103         }
 104
 105         nodes = XMALLOCN(ir_node*, n);
 106
 107         DBG((dbg, LEVEL_1, "live:\n"));
 108         i = 0;
 109         foreach_ir_nodeset(&live, irn, iter) {
 110                 DBG((dbg, LEVEL_1, "\t%+F\n", irn));
 111                 nodes[i] = irn;
 112                 i++;
 113         }
 114         ir_nodeset_destroy(&live);
 115
 116         perm = be_new_Perm(cls, bl, n, nodes);
 117         sched_add_after(pos, perm);
 118         free(nodes);
 119
 120         curr = perm;
 121         for (i = 0; i < n; ++i) {
 122                 ir_node *perm_op = get_irn_n(perm, i);
 123                 const arch_register_t *reg = arch_get_irn_register(perm_op);
 124                 be_ssa_construction_env_t senv;
 125
 126                 ir_mode *mode = get_irn_mode(perm_op);
 127                 ir_node *proj = new_r_Proj(perm, mode, i);
 128                 arch_set_irn_register(proj, reg);
 129
 130                 curr = proj;
 131
 132                 be_ssa_construction_init(&senv, birg->irg);
 133                 be_ssa_construction_add_copy(&senv, perm_op);
 134                 be_ssa_construction_add_copy(&senv, proj);
 135                 be_ssa_construction_fix_users(&senv, perm_op);
 136                 be_ssa_construction_update_liveness_phis(&senv, lv);
 137                 be_liveness_update(lv, perm_op);
 138                 be_liveness_update(lv, proj);
 139                 be_ssa_construction_destroy(&senv);
 140         }
 141
 142         return perm;
 143 }
 144
 145 static int blocks_removed;
 146
 147 /**
 148  * Post-block-walker: Find blocks containing only one jump and
 149  * remove them.
 150  */
 151 static void remove_empty_block(ir_node *block)
 152 {
 153         const ir_edge_t *edge, *next;
 154         int      i, arity;
 155         ir_node *node;
 156         ir_node *pred;
 157         ir_node *succ_block;
 158         ir_node *jump = NULL;
 159
 160         if (irn_visited_else_mark(block))
 161                 return;
 162
 163         if (get_Block_n_cfgpreds(block) != 1)
 164                 goto check_preds;
 165
 166         sched_foreach(block, node) {
 167                 if (! is_Jmp(node)
 168                                 && !(arch_irn_get_flags(node) & arch_irn_flags_simple_jump))
 169                         goto check_preds;
 170                 if (jump != NULL) {
 171                         /* we should never have 2 jumps in a block */
 172                         panic("found 2 jumps in a block");
 173                 }
 174                 jump = node;
 175         }
 176
 177         if (jump == NULL)
 178                 goto check_preds;
 179
 180         pred       = get_Block_cfgpred(block, 0);
 181         succ_block = NULL;
 182         foreach_out_edge_safe(jump, edge, next) {
 183                 int pos = get_edge_src_pos(edge);
 184
 185                 assert(succ_block == NULL);
 186                 succ_block = get_edge_src_irn(edge);
 187                 if (has_Block_entity(succ_block) && has_Block_entity(block)) {
 188                         /*
 189                          * Currently we can add only one label for a block.
 190                          * Therefore we cannot combine them if  both block already have one.
 191                          */
 192                         goto check_preds;
 193                 }
 194
 195                 set_irn_n(succ_block, pos, pred);
 196         }
 197
 198         if (has_Block_entity(block)) {
 199                 /* move the label to the successor block */
 200                 ir_entity *entity = get_Block_entity(block);
 201                 set_Block_entity(succ_block, entity);
 202         }
 203
 204         /* there can be some non-scheduled Pin nodes left in the block, move them
 205          * to the succ block (Pin) or pred block (Sync) */
 206         foreach_out_edge_safe(block, edge, next) {
 207                 node = get_edge_src_irn(edge);
 208
 209                 if (node == jump)
 210                         continue;
 211                 if (is_Block(node)) {
 212                         /* a Block->Block edge: This should be the MacroBlock
 213                            edge, ignore it. */
 214                         assert(get_Block_MacroBlock(node) == block && "Wrong Block->Block edge");
 215                         continue;
 216                 }
 217                 /* we simply kill Pins, because there are some strange interactions
 218                  * between jump threading, which produce PhiMs with Pins, we simply
 219                  * kill the pins here, everything is scheduled anyway */
 220                 if (is_Pin(node)) {
 221                         exchange(node, get_Pin_op(node));
 222                         continue;
 223                 }
 224                 if (is_Sync(node)) {
 225                         set_nodes_block(node, get_nodes_block(pred));
 226                         continue;
 227                 }
 228                 if (is_End(node)) { /* End-keep, reroute it to the successor */
 229                         int pos = get_edge_src_pos(edge);
 230                         set_irn_n(node, pos, succ_block);
 231                         continue;
 232                 }
 233                 panic("Unexpected node %+F in block %+F with empty schedule", node, block);
 234         }
 235
 236         set_Block_cfgpred(block, 0, new_Bad());
 237         kill_node(jump);
 238         blocks_removed = 1;
 239
 240         /* check predecessor */
 241         remove_empty_block(get_nodes_block(pred));
 242         return;
 243
 244 check_preds:
 245         arity = get_Block_n_cfgpreds(block);
 246         for (i = 0; i < arity; ++i) {
 247                 ir_node *pred = get_Block_cfgpred_block(block, i);
 248                 remove_empty_block(pred);
 249         }
 250 }
 251
 252 /* removes basic blocks that just contain a jump instruction */
 253 int be_remove_empty_blocks(ir_graph *irg)
 254 {
 255         ir_node *end;
 256         int      i, arity;
 257
 258         blocks_removed = 0;
 259
 260         ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
 261         inc_irg_visited(irg);
 262         remove_empty_block(get_irg_end_block(irg));
 263         end   = get_irg_end(irg);
 264         arity = get_irn_arity(end);
 265         for (i = 0; i < arity; ++i) {
 266                 ir_node *pred = get_irn_n(end, i);
 267                 if (!is_Block(pred))
 268                         continue;
 269                 remove_empty_block(pred);
 270         }
 271         ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
 272
 273         if (blocks_removed) {
 274                 /* invalidate analysis info */
 275                 set_irg_doms_inconsistent(irg);
 276                 set_irg_extblk_inconsistent(irg);
 277                 set_irg_outs_inconsistent(irg);
 278                 set_irg_loopinfo_inconsistent(irg);
 279         }
 280         return blocks_removed;
 281 }
 282
 283 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_irgmod);
 284 void be_init_irgmod(void)
 285 {
 286         FIRM_DBG_REGISTER(dbg, "firm.be.irgmod");
 287 }