nsz Git - libfirm/blob - ir/ir/irgmod.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    Support for ir graph modification.
  23  * @author   Martin Trapp, Christian Schaefer, Goetz Lindenmaier
  24  * @version  $Id$
  25  */
  26 #include "config.h"
  27
  28 #include "irflag_t.h"
  29 #include "irgwalk.h"
  30 #include "irnode_t.h"
  31 #include "irgraph_t.h"
  32 #include "irgmod.h"
  33 #include "array.h"
  34 #include "ircons.h"
  35 #include "irhooks.h"
  36 #include "iredges_t.h"
  37 #include "irtools.h"
  38 #include "error.h"
  39
  40 /**
  41  * Turns a node into a "useless" Tuple.  The Tuple just forms a tuple
  42  * from several inputs.
  43  * This is useful if a node returning a tuple is removed, but the Projs
  44  * extracting values from the tuple are not available.
  45  */
  46 void turn_into_tuple(ir_node *node, int arity)
  47 {
  48         ir_graph *irg = get_irn_irg(node);
  49         ir_node **in  = ALLOCAN(ir_node*, arity);
  50         int       i;
  51
  52         /* construct a new in array, with every input being bad */
  53         for (i = 0; i < arity; ++i) {
  54                 in[i] = new_r_Bad(irg);
  55         }
  56         set_irn_in(node, arity, in);
  57         set_irn_op(node, op_Tuple);
  58 }
  59
  60 /**
  61  * Insert irnode `new' in place of irnode `old'
  62  * Since `new' may be bigger than `old' replace `old'
  63  * by an op_Id which is smaller than everything.
  64  */
  65 void exchange(ir_node *old, ir_node *nw)
  66 {
  67         ir_graph *irg;
  68
  69         assert(old && nw);
  70         assert(old != nw && "Exchanging node with itself is not allowed");
  71
  72         irg = get_irn_irg(old);
  73         assert(irg == get_irn_irg(nw) && "New node must be in same irg as old node");
  74
  75         hook_replace(old, nw);
  76
  77         /*
  78          * If new outs are on, we can skip the id node creation and reroute
  79          * the edges from the old node to the new directly.
  80          */
  81         if (edges_activated(irg)) {
  82                 /* copy all dependencies from old to new */
  83                 add_irn_deps(nw, old);
  84
  85                 edges_reroute(old, nw, irg);
  86                 edges_reroute_kind(old, nw, EDGE_KIND_DEP, irg);
  87                 edges_node_deleted(old, irg);
  88                 /* noone is allowed to reference this node anymore */
  89                 set_irn_op(old, op_Deleted);
  90         } else {
  91                 /* Else, do it the old-fashioned way. */
  92                 ir_node *block;
  93
  94                 hook_turn_into_id(old);
  95
  96                 block = old->in[0];
  97                 if (! block) {
  98                         block = is_Block(nw) ? nw : get_nodes_block(nw);
  99
 100                         if (! block) {
 101                                 panic("cannot find legal block for id");
 102                         }
 103                 }
 104
 105                 if (get_irn_op(old)->opar == oparity_dynamic) {
 106                         DEL_ARR_F(get_irn_in(old));
 107                 }
 108
 109                 old->op    = op_Id;
 110                 old->in    = NEW_ARR_D (ir_node *, irg->obst, 2);
 111                 old->in[0] = block;
 112                 old->in[1] = nw;
 113         }
 114 }
 115
 116 /*--------------------------------------------------------------------*/
 117 /*  Functionality for collect_phis                                    */
 118 /*--------------------------------------------------------------------*/
 119
 120 /**
 121  * Walker: links all Phi nodes to their Blocks lists,
 122  *         all Proj nodes to there predecessors and all
 123  *         partBlocks to there MacroBlock header.
 124  */
 125 static void collect_phiprojs_walker(ir_node *n, void *env)
 126 {
 127         ir_node *pred;
 128         (void) env;
 129
 130         if (is_Phi(n)) {
 131                 ir_node *block = get_nodes_block(n);
 132                 add_Block_phi(block, n);
 133         } else if (is_Proj(n)) {
 134                 pred = n;
 135                 do {
 136                         pred = get_Proj_pred(pred);
 137                 } while (is_Proj(pred));
 138
 139                 set_irn_link(n, get_irn_link(pred));
 140                 set_irn_link(pred, n);
 141         } else if (is_Block(n)) {
 142                 ir_node *mbh = get_Block_MacroBlock(n);
 143
 144                 if (mbh != n) {
 145                         set_irn_link(n, get_irn_link(mbh));
 146                         set_irn_link(mbh, n);
 147                 }
 148         }
 149 }
 150
 151 void collect_phiprojs(ir_graph *irg)
 152 {
 153         assert((ir_resources_reserved(irg) & (IR_RESOURCE_IRN_LINK|IR_RESOURCE_PHI_LIST)) ==
 154                 (IR_RESOURCE_IRN_LINK|IR_RESOURCE_PHI_LIST));
 155         irg_walk_graph(irg, firm_clear_node_and_phi_links, collect_phiprojs_walker, NULL);
 156 }
 157
 158 /*--------------------------------------------------------------------*/
 159 /*  Functionality for part_block                                      */
 160 /*--------------------------------------------------------------------*/
 161
 162 /**
 163  * Moves node and all predecessors of node from from_bl to to_bl.
 164  * Does not move predecessors of Phi nodes (or block nodes).
 165  */
 166 static void move(ir_node *node, ir_node *from_bl, ir_node *to_bl)
 167 {
 168         int i, arity;
 169
 170         /* move this node */
 171         set_nodes_block(node, to_bl);
 172
 173         /* move its Projs */
 174         if (get_irn_mode(node) == mode_T) {
 175                 ir_node *proj = get_irn_link(node);
 176                 while (proj) {
 177                         if (get_nodes_block(proj) == from_bl)
 178                                 set_nodes_block(proj, to_bl);
 179                         proj = get_irn_link(proj);
 180                 }
 181         }
 182
 183         /* recursion ... */
 184         if (is_Phi(node))
 185                 return;
 186
 187         arity = get_irn_arity(node);
 188         for (i = 0; i < arity; i++) {
 189                 ir_node *pred = get_irn_n(node, i);
 190                 if (get_nodes_block(pred) == from_bl)
 191                         move(pred, from_bl, to_bl);
 192         }
 193 }
 194
 195 void part_block(ir_node *node)
 196 {
 197         ir_node *new_block, *old_block, *mbh;
 198         ir_node *phi, *jmp, *next, *block;
 199         ir_graph *rem = current_ir_graph;
 200
 201         /* Turn off optimizations so that blocks are not merged again. */
 202         int rem_opt = get_opt_optimize();
 203         set_optimize(0);
 204
 205         current_ir_graph = get_irn_irg(node);
 206
 207         /* Transform the control flow */
 208         old_block = get_nodes_block(node);
 209         mbh       = get_Block_MacroBlock(old_block);
 210         new_block = new_Block(get_Block_n_cfgpreds(old_block),
 211                               get_Block_cfgpred_arr(old_block));
 212
 213         if (mbh != old_block) {
 214                 /* we splitting a partBlock */
 215                 set_Block_MacroBlock(new_block, mbh);
 216         } else {
 217                 /* we are splitting a header: this creates a new header */
 218                 set_Block_MacroBlock(new_block, new_block);
 219         }
 220
 221         /* create a jump from new_block to old_block, which is now the lower one */
 222         jmp = new_r_Jmp(new_block);
 223         set_irn_in(old_block, 1, &jmp);
 224
 225         /* move node and its predecessors to new_block */
 226         move(node, old_block, new_block);
 227
 228         /* move Phi nodes to new_block */
 229         phi = get_Block_phis(old_block);
 230         set_Block_phis(new_block, phi);
 231         set_Block_phis(old_block, NULL);
 232         while (phi) {
 233                 set_nodes_block(phi, new_block);
 234                 phi = get_Phi_next(phi);
 235         }
 236
 237         /* rewire partBlocks: This is necessary, because old_block is a new MacroBlock
 238            header now */
 239         if (mbh != old_block) {
 240                 ir_node *list = NULL;
 241
 242                 /* move blocks from mbh to old_block if old_block dominates them */
 243                 block = get_irn_link(mbh);
 244
 245                 /* mbh's list will be rebuild */
 246                 set_irn_link(mbh, NULL);
 247                 /* old_block is a new mbh */
 248                 set_Block_MacroBlock(old_block, old_block);
 249
 250                 /* note that we must splice the list of partBlock here */
 251                 for (; block != NULL; block = next) {
 252                         ir_node *curr = block;
 253                         assert(is_Block(curr));
 254
 255                         next = get_irn_link(block);
 256
 257                         if (block == old_block) {
 258                                 /* this effectively removed old_block from mbh's list */
 259                                 continue;
 260                         }
 261
 262                         assert(get_Block_MacroBlock(curr) == mbh);
 263
 264                         for (;;) {
 265                                 if (curr == old_block) {
 266                                         /* old_block dominates the block, so old_block will be
 267                                            the new macro block header */
 268                                         set_Block_MacroBlock(block, old_block);
 269                                         set_irn_link(block, list);
 270                                         list = block;
 271                                         break;
 272                                 }
 273                                 if (curr == mbh) {
 274                                         /* leave it in the mbh */
 275                                         set_irn_link(block, get_irn_link(mbh));
 276                                         set_irn_link(mbh, block);
 277                                         break;
 278                                 }
 279
 280                                 assert(get_Block_n_cfgpreds(curr) == 1);
 281                                 curr = get_Block_cfgpred_block(curr, 0);
 282                         }
 283                 }
 284                 /* beware: do NOT directly manipulate old_block's list, as old_block is
 285                    in mbh's list and this would destroy the list! */
 286                 set_irn_link(old_block, list);
 287
 288                 /* finally add new_block to mbh's list */
 289                 set_irn_link(new_block, get_irn_link(mbh));
 290                 set_irn_link(mbh, new_block);
 291         } else {
 292                 /* old_block is the mbh, as well as new_block */
 293                 set_Block_MacroBlock(new_block, new_block);
 294         }
 295
 296         set_optimize(rem_opt);
 297         current_ir_graph = rem;
 298 }
 299
 300 /* kill a node by setting its predecessors to Bad and finally exchange the node by Bad itself. */
 301 void kill_node(ir_node *node)
 302 {
 303         ir_graph *irg = get_irn_irg(node);
 304         ir_node *bad = get_irg_bad(irg);
 305         int i;
 306
 307         for (i = get_irn_arity(node) - 1; i >= -1; --i) {
 308                 set_irn_n(node, i, bad);
 309         }
 310         exchange(node, bad);
 311 }