nsz Git - libfirm/blob - ir/ana/analyze_irg_args.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      read/write analyze of graph argument, which have mode reference.
  23  * @author     Beyhan Veliev
  24  */
  25 #include "config.h"
  26
  27 #include <stdlib.h>
  28
  29 #include "irouts.h"
  30 #include "irnode_t.h"
  31 #include "irmode_t.h"
  32 #include "array_t.h"
  33 #include "irprog.h"
  34 #include "entity_t.h"
  35
  36 #include "analyze_irg_args.h"
  37
  38 /**
  39  * Walk recursive the successors of a graph argument
  40  * with mode reference and mark if it will be read,
  41  * written or stored.
  42  *
  43  * @param arg   The graph argument with mode reference,
  44  *             that must be checked.
  45  */
  46 static ptr_access_kind analyze_arg(ir_node *arg, ptr_access_kind bits)
  47 {
  48         int i, p;
  49         ir_node *succ;
  50
  51         /* We must visit a node once to avoid endless recursion.*/
  52         mark_irn_visited(arg);
  53
  54         for (i = get_irn_n_outs(arg) - 1; i >= 0; --i) {
  55                 succ = get_irn_out(arg, i);
  56
  57                 /* We was here.*/
  58                 if (irn_visited(succ))
  59                         continue;
  60
  61                 /* We should not walk over the memory edge.*/
  62                 if (get_irn_mode(succ) == mode_M)
  63                         continue;
  64
  65                 /* If we reach with the recursion a Call node and our reference
  66                    isn't the address of this Call we accept that the reference will
  67                    be read and written if the graph of the method represented by
  68                    "Call" isn't computed else we analyze that graph. If our
  69                    reference is the address of this
  70                    Call node that mean the reference will be read.*/
  71                 switch (get_irn_opcode(succ)) {
  72
  73                 case iro_Call: {
  74                         ir_node *ptr  = get_Call_ptr(succ);
  75
  76                         if (ptr == arg) {
  77                                 /* Hmm: not sure what this is, most likely a read */
  78                                 bits |= ptr_access_read;
  79                         } else {
  80                                 ir_entity *meth_ent;
  81
  82                                 if (is_SymConst_addr_ent(ptr)) {
  83                                         meth_ent = get_SymConst_entity(ptr);
  84
  85                                         for (p = get_Call_n_params(succ) - 1; p >= 0; --p) {
  86                                                 if (get_Call_param(succ, p) == arg) {
  87                                                         /* an arg can be used more than once ! */
  88                                                         bits |= get_method_param_access(meth_ent, p);
  89                                                 }
  90                                         }
  91                                 } else if (is_Sel(ptr) && get_irp_callee_info_state() == irg_callee_info_consistent) {
  92                                         /* is be a polymorphic call but callee information is available */
  93                                         int n_params = get_Call_n_params(succ);
  94                                         int c;
  95
  96                                         /* simply look into ALL possible callees */
  97                                         for (c = get_Call_n_callees(succ) - 1; c >= 0; --c) {
  98                                                 meth_ent = get_Call_callee(succ, c);
  99
 100                                                 /* unknown_entity is used to signal that we don't know what is called */
 101                                                 if (is_unknown_entity(meth_ent)) {
 102                                                         bits |= ptr_access_all;
 103                                                         break;
 104                                                 }
 105
 106                                                 for (p = n_params - 1; p >= 0; --p) {
 107                                                         if (get_Call_param(succ, p) == arg) {
 108                                                                 /* an arg can be used more than once ! */
 109                                                                 bits |= get_method_param_access(meth_ent, p);
 110                                                         }
 111                                                 }
 112                                         }
 113                                 } else /* can do anything */
 114                                         bits |= ptr_access_all;
 115                         }
 116
 117                         /* search stops here anyway */
 118                         continue;
 119                 }
 120                 case iro_Store:
 121                         /* We have reached a Store node => the reference is written or stored. */
 122                         if (get_Store_ptr(succ) == arg) {
 123                                 /* written to */
 124                                 bits |= ptr_access_write;
 125                         } else {
 126                                 /* stored itself */
 127                                 bits |= ptr_access_store;
 128                         }
 129
 130                         /* search stops here anyway */
 131                         continue;
 132
 133                 case iro_Load:
 134                         /* We have reached a Load node => the reference is read. */
 135                         bits |= ptr_access_read;
 136
 137                         /* search stops here anyway */
 138                         continue;
 139
 140                 case iro_Conv:
 141                         /* our address is casted into something unknown. Break our search. */
 142                         bits = ptr_access_all;
 143                         break;
 144
 145                 default:
 146                         break;
 147                 }
 148
 149                 /* If we know that, the argument will be read, write and stored, we
 150                    can break the recursion.*/
 151                 if (bits == ptr_access_all) {
 152                         bits = ptr_access_all;
 153                         break;
 154                 }
 155
 156                 /*
 157                  * A calculation that do not lead to a reference mode ends our search.
 158                  * This is dangerous: It would allow to cast into integer and that cast back ...
 159                  * so, when we detect a Conv we go mad, see the Conv case above.
 160                  */
 161                 if (!mode_is_reference(get_irn_mode(succ)))
 162                         continue;
 163
 164                 /* follow further the address calculation */
 165                 bits = analyze_arg(succ, bits);
 166         }
 167         set_irn_link(arg, NULL);
 168         return bits;
 169 }
 170
 171 /**
 172  * Check if a argument of the ir graph with mode
 173  * reference is read, write or both.
 174  *
 175  * @param irg   The ir graph to analyze.
 176  */
 177 static void analyze_ent_args(ir_entity *ent)
 178 {
 179         ir_graph *irg;
 180         ir_node *irg_args, *arg;
 181         ir_mode *arg_mode;
 182         int nparams, i;
 183         long proj_nr;
 184         ir_type *mtp;
 185         ptr_access_kind *rw_info;
 186
 187         mtp     = get_entity_type(ent);
 188         nparams = get_method_n_params(mtp);
 189
 190         ent->attr.mtd_attr.param_access = NEW_ARR_F(ptr_access_kind, nparams);
 191
 192         /* If the method haven't parameters we have
 193          * nothing to do.
 194          */
 195         if (nparams <= 0)
 196                 return;
 197
 198         irg = get_entity_irg(ent);
 199
 200   /* we have not yet analyzed the graph, set ALL access for pointer args */
 201         for (i = nparams - 1; i >= 0; --i) {
 202                 ir_type *type = get_method_param_type(mtp, i);
 203                 ent->attr.mtd_attr.param_access[i] = is_Pointer_type(type) ? ptr_access_all : ptr_access_none;
 204         }
 205
 206         if (! irg) {
 207                 /* no graph, no better info */
 208                 return;
 209         }
 210
 211         assure_irg_outs(irg);
 212
 213         irg_args = get_irg_args(irg);
 214
 215         /* A array to save the information for each argument with
 216            mode reference.*/
 217         NEW_ARR_A(ptr_access_kind, rw_info, nparams);
 218
 219         /* We initialize the element with none state. */
 220         for (i = nparams - 1; i >= 0; --i)
 221                 rw_info[i] = ptr_access_none;
 222
 223         /* search for arguments with mode reference
 224            to analyze them.*/
 225         for (i = get_irn_n_outs(irg_args) - 1; i >= 0; --i) {
 226                 arg      = get_irn_out(irg_args, i);
 227                 arg_mode = get_irn_mode(arg);
 228                 proj_nr  = get_Proj_proj(arg);
 229
 230                 if (mode_is_reference(arg_mode))
 231                         rw_info[proj_nr] |= analyze_arg(arg, rw_info[proj_nr]);
 232         }
 233
 234         /* copy the temporary info */
 235         memcpy(ent->attr.mtd_attr.param_access, rw_info,
 236                 nparams * sizeof(ent->attr.mtd_attr.param_access[0]));
 237
 238 #if 0
 239         printf("\n%s:\n", get_entity_name(ent));
 240         for (i = 0; i < nparams; ++i) {
 241                 if (is_Pointer_type(get_method_param_type(mtp, i)))
 242                         if (ent->attr.mtd_attr.param_access[i] != ptr_access_none) {
 243                                 printf("  Pointer Arg %d access: ", i);
 244                                 if (ent->attr.mtd_attr.param_access[i] & ptr_access_read)
 245                                         printf("READ ");
 246                                 if (ent->attr.mtd_attr.param_access[i] & ptr_access_write)
 247                                         printf("WRITE ");
 248                                 if (ent->attr.mtd_attr.param_access[i] & ptr_access_store)
 249                                         printf("STORE ");
 250                                 printf("\n");
 251                         }
 252         }
 253 #endif
 254 }
 255
 256 void analyze_irg_args(ir_graph *irg)
 257 {
 258         ir_entity *ent;
 259
 260         if (irg == get_const_code_irg())
 261                 return;
 262
 263         ent = get_irg_entity(irg);
 264         if (! ent)
 265                 return;
 266
 267         if (! ent->attr.mtd_attr.param_access)
 268                 analyze_ent_args(ent);
 269 }
 270
 271 ptr_access_kind get_method_param_access(ir_entity *ent, size_t pos)
 272 {
 273 #ifndef NDEBUG
 274         ir_type *mtp = get_entity_type(ent);
 275         int is_variadic = get_method_variadicity(mtp) == variadicity_variadic;
 276
 277         assert(is_variadic || pos < get_method_n_params(mtp));
 278 #endif
 279
 280         if (ent->attr.mtd_attr.param_access) {
 281                 if (pos < ARR_LEN(ent->attr.mtd_attr.param_access))
 282                         return ent->attr.mtd_attr.param_access[pos];
 283                 else
 284                         return ptr_access_all;
 285         }
 286
 287         analyze_ent_args(ent);
 288
 289         if (pos < ARR_LEN(ent->attr.mtd_attr.param_access))
 290                 return ent->attr.mtd_attr.param_access[pos];
 291         else
 292                 return ptr_access_all;
 293 }
 294
 295 /* Weights for parameters */
 296 enum args_weight {
 297         null_weight          = 0,   /**< If can't be anything optimized. */
 298         binop_weight         = 1,   /**< If the argument have mode_weight and take part in binop. */
 299         const_binop_weight   = 1,   /**< If the argument have mode_weight and take part in binop with a constant.*/
 300         cmp_weight           = 4,   /**< If the argument take part in cmp. */
 301         const_cmp_weight     = 10,  /**< If the argument take part in cmp with a constant. */
 302         indirect_call_weight = 125, /**< If the argument is the address of an indirect Call. */
 303 };
 304
 305 /**
 306  * Compute the weight of a method parameter
 307  *
 308  * @param arg  The parameter them weight muss be computed.
 309  */
 310 static unsigned calc_method_param_weight(ir_node *arg)
 311 {
 312         int      i, j, k;
 313         ir_node  *succ, *op;
 314         unsigned weight = null_weight;
 315
 316         /* We mark the nodes to avoid endless recursion */
 317         mark_irn_visited(arg);
 318
 319         for (i = get_irn_n_outs(arg) - 1; i >= 0; i--) {
 320                 succ = get_irn_out(arg, i);
 321
 322                 /* We was here.*/
 323                 if (irn_visited(succ))
 324                         continue;
 325
 326                 /* We should not walk over the memory edge.*/
 327                 if (get_irn_mode(succ) == mode_M)
 328                         continue;
 329
 330                 switch (get_irn_opcode(succ)) {
 331                 case iro_Call:
 332                         if (get_Call_ptr(succ) == arg) {
 333                                 /* the arguments is used as an pointer input for a call,
 334                                    we can probably change an indirect Call into a direct one. */
 335                                 weight += indirect_call_weight;
 336                         }
 337                         break;
 338                 case iro_Cmp:
 339                         /* We have reached a cmp and we must increase the
 340                            weight with the cmp_weight. */
 341                         if (get_Cmp_left(succ) == arg)
 342                                 op = get_Cmp_right(succ);
 343                         else
 344                                 op = get_Cmp_left(succ);
 345
 346                         if (is_irn_constlike(op)) {
 347                                 weight += const_cmp_weight;
 348                         } else
 349                                 weight += cmp_weight;
 350                         break;
 351                 case iro_Cond:
 352                         /* the argument is used for a SwitchCond, a big win */
 353                         weight += const_cmp_weight * get_irn_n_outs(succ);
 354                         break;
 355                 case iro_Id:
 356                         /* when looking backward we might find Id nodes */
 357                         weight += calc_method_param_weight(succ);
 358                         break;
 359                 case iro_Tuple:
 360                         /* unoptimized tuple */
 361                         for (j = get_Tuple_n_preds(succ) - 1; j >= 0; --j) {
 362                                 ir_node *pred = get_Tuple_pred(succ, j);
 363                                 if (pred == arg) {
 364                                         /* look for Proj(j) */
 365                                         for (k = get_irn_n_outs(succ) - 1; k >= 0; --k) {
 366                                                 ir_node *succ_succ = get_irn_out(succ, k);
 367                                                 if (is_Proj(succ_succ)) {
 368                                                         if (get_Proj_proj(succ_succ) == j) {
 369                                                                 /* found */
 370                                                                 weight += calc_method_param_weight(succ_succ);
 371                                                         }
 372                                                 } else {
 373                                                         /* this should NOT happen */
 374                                                 }
 375                                         }
 376                                 }
 377                         }
 378                         break;
 379                 default:
 380                         if (is_binop(succ)) {
 381                                 /* We have reached a BinOp and we must increase the
 382                                    weight with the binop_weight. If the other operand of the
 383                                    BinOp is a constant we increase the weight with const_binop_weight
 384                                    and call the function recursive.
 385                                  */
 386                                 if (get_binop_left(succ) == arg)
 387                                         op = get_binop_right(succ);
 388                                 else
 389                                         op = get_binop_left(succ);
 390
 391                                 if (is_irn_constlike(op)) {
 392                                         weight += const_binop_weight;
 393                                         weight += calc_method_param_weight(succ);
 394                                 } else
 395                                         weight += binop_weight;
 396                         } else if (is_unop(succ)) {
 397                                 /* We have reached a binop and we must increase the
 398                                    weight with the const_binop_weight and call the function recursive.*/
 399                                 weight += const_binop_weight;
 400                                 weight += calc_method_param_weight(succ);
 401                         }
 402                         break;
 403                 }
 404         }
 405         set_irn_link(arg, NULL);
 406         return weight;
 407 }
 408
 409 /**
 410  * Calculate a weight for each argument of an entity.
 411  *
 412  * @param ent  The entity of the ir_graph.
 413  */
 414 static void analyze_method_params_weight(ir_entity *ent)
 415 {
 416         ir_type  *mtp;
 417         ir_graph *irg;
 418         int      nparams, i, proj_nr;
 419         ir_node  *irg_args, *arg;
 420
 421         mtp      = get_entity_type(ent);
 422         nparams  = get_method_n_params(mtp);
 423
 424         /* allocate a new array. currently used as 'analysed' flag */
 425         ent->attr.mtd_attr.param_weight = NEW_ARR_F(unsigned, nparams);
 426
 427         /* If the method haven't parameters we have nothing to do. */
 428         if (nparams <= 0)
 429           return;
 430
 431         /* First we initialize the parameter weights with 0. */
 432         for (i = nparams - 1; i >= 0; i--)
 433                 ent->attr.mtd_attr.param_weight[i] = null_weight;
 434
 435         irg = get_entity_irg(ent);
 436         if (irg == NULL) {
 437                 /* no graph, no better info */
 438                 return;
 439         }
 440
 441         /* Call algorithm that computes the out edges */
 442         assure_irg_outs(irg);
 443
 444         irg_args = get_irg_args(irg);
 445         for (i = get_irn_n_outs(irg_args) - 1; i >= 0; --i) {
 446                 arg     = get_irn_out(irg_args, i);
 447                 proj_nr = get_Proj_proj(arg);
 448                 ent->attr.mtd_attr.param_weight[proj_nr] += calc_method_param_weight(arg);
 449         }
 450 }
 451
 452 unsigned get_method_param_weight(ir_entity *ent, size_t pos)
 453 {
 454         if (ent->attr.mtd_attr.param_weight) {
 455                 if (pos < ARR_LEN(ent->attr.mtd_attr.param_weight))
 456                         return ent->attr.mtd_attr.param_weight[pos];
 457                 else
 458                         return null_weight;
 459         }
 460
 461         analyze_method_params_weight(ent);
 462
 463         if (pos < ARR_LEN(ent->attr.mtd_attr.param_weight))
 464                 return ent->attr.mtd_attr.param_weight[pos];
 465         else
 466                 return null_weight;
 467 }
 468
 469 void analyze_irg_args_weight(ir_graph *irg)
 470 {
 471         ir_entity *entity = get_irg_entity(irg);
 472         if (entity == NULL)
 473                 return;
 474
 475         assert(is_method_entity(entity));
 476         if (entity->attr.mtd_attr.param_weight != NULL)
 477                 return;
 478
 479         ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
 480         inc_irg_visited(irg);
 481         analyze_method_params_weight(entity);
 482         ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
 483 }