gcc/tree.c

   1 /* Language-independent node constructors for parse phase of GNU compiler.
   2    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to the Free
  20 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  21 02110-1301, USA.  */
  22
  23 /* This file contains the low level primitives for operating on tree nodes,
  24    including allocation, list operations, interning of identifiers,
  25    construction of data type nodes and statement nodes,
  26    and construction of type conversion nodes.  It also contains
  27    tables index by tree code that describe how to take apart
  28    nodes of that code.
  29
  30    It is intended to be language-independent, but occasionally
  31    calls language-dependent routines defined (for C) in typecheck.c.  */
  32
  33 #include "config.h"
  34 #include "system.h"
  35 #include "coretypes.h"
  36 #include "tm.h"
  37 #include "flags.h"
  38 #include "tree.h"
  39 #include "real.h"
  40 #include "tm_p.h"
  41 #include "function.h"
  42 #include "obstack.h"
  43 #include "toplev.h"
  44 #include "ggc.h"
  45 #include "hashtab.h"
  46 #include "output.h"
  47 #include "target.h"
  48 #include "langhooks.h"
  49 #include "tree-iterator.h"
  50 #include "basic-block.h"
  51 #include "tree-flow.h"
  52 #include "params.h"
  53 #include "pointer-set.h"
  54
  55 /* Each tree code class has an associated string representation.
  56    These must correspond to the tree_code_class entries.  */
  57
  58 const char *const tree_code_class_strings[] =
  59 {
  60   "exceptional",
  61   "constant",
  62   "type",
  63   "declaration",
  64   "reference",
  65   "comparison",
  66   "unary",
  67   "binary",
  68   "statement",
  69   "expression",
  70 };
  71
  72 /* obstack.[ch] explicitly declined to prototype this.  */
  73 extern int _obstack_allocated_p (struct obstack *h, void *obj);
  74
  75 #ifdef GATHER_STATISTICS
  76 /* Statistics-gathering stuff.  */
  77
  78 int tree_node_counts[(int) all_kinds];
  79 int tree_node_sizes[(int) all_kinds];
  80
  81 /* Keep in sync with tree.h:enum tree_node_kind.  */
  82 static const char * const tree_node_kind_names[] = {
  83   "decls",
  84   "types",
  85   "blocks",
  86   "stmts",
  87   "refs",
  88   "exprs",
  89   "constants",
  90   "identifiers",
  91   "perm_tree_lists",
  92   "temp_tree_lists",
  93   "vecs",
  94   "binfos",
  95   "phi_nodes",
  96   "ssa names",
  97   "constructors",
  98   "random kinds",
  99   "lang_decl kinds",
 100   "lang_type kinds",
 101   "omp clauses"
 102 };
 103 #endif /* GATHER_STATISTICS */
 104
 105 /* Unique id for next decl created.  */
 106 static GTY(()) int next_decl_uid;
 107 /* Unique id for next type created.  */
 108 static GTY(()) int next_type_uid = 1;
 109
 110 /* Since we cannot rehash a type after it is in the table, we have to
 111    keep the hash code.  */
 112
 113 struct type_hash GTY(())
 114 {
 115   unsigned long hash;
 116   tree type;
 117 };
 118
 119 /* Initial size of the hash table (rounded to next prime).  */
 120 #define TYPE_HASH_INITIAL_SIZE 1000
 121
 122 /* Now here is the hash table.  When recording a type, it is added to
 123    the slot whose index is the hash code.  Note that the hash table is
 124    used for several kinds of types (function types, array types and
 125    array index range types, for now).  While all these live in the
 126    same table, they are completely independent, and the hash code is
 127    computed differently for each of these.  */
 128
 129 static GTY ((if_marked ("type_hash_marked_p"), param_is (struct type_hash)))
 130      htab_t type_hash_table;
 131
 132 /* Hash table and temporary node for larger integer const values.  */
 133 static GTY (()) tree int_cst_node;
 134 static GTY ((if_marked ("ggc_marked_p"), param_is (union tree_node)))
 135      htab_t int_cst_hash_table;
 136
 137 /* General tree->tree mapping  structure for use in hash tables.  */
 138
 139
 140 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
 141      htab_t debug_expr_for_decl;
 142
 143 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
 144      htab_t value_expr_for_decl;
 145
 146 static GTY ((if_marked ("tree_int_map_marked_p"), param_is (struct tree_int_map)))
 147   htab_t init_priority_for_decl;
 148
 149 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
 150   htab_t restrict_base_for_decl;
 151
 152 struct tree_int_map GTY(())
 153 {
 154   tree from;
 155   unsigned short to;
 156 };
 157 static unsigned int tree_int_map_hash (const void *);
 158 static int tree_int_map_eq (const void *, const void *);
 159 static int tree_int_map_marked_p (const void *);
 160 static void set_type_quals (tree, int);
 161 static int type_hash_eq (const void *, const void *);
 162 static hashval_t type_hash_hash (const void *);
 163 static hashval_t int_cst_hash_hash (const void *);
 164 static int int_cst_hash_eq (const void *, const void *);
 165 static void print_type_hash_statistics (void);
 166 static void print_debug_expr_statistics (void);
 167 static void print_value_expr_statistics (void);
 168 static tree make_vector_type (tree, int, enum machine_mode);
 169 static int type_hash_marked_p (const void *);
 170 static unsigned int type_hash_list (tree, hashval_t);
 171 static unsigned int attribute_hash_list (tree, hashval_t);
 172
 173 tree global_trees[TI_MAX];
 174 tree integer_types[itk_none];
 175
 176 unsigned char tree_contains_struct[256][64];
 177
 178 /* Number of operands for each OpenMP clause.  */
 179 unsigned const char omp_clause_num_ops[] =
 180 {
 181   0, /* OMP_CLAUSE_ERROR  */
 182   1, /* OMP_CLAUSE_PRIVATE  */
 183   1, /* OMP_CLAUSE_SHARED  */
 184   1, /* OMP_CLAUSE_FIRSTPRIVATE  */
 185   1, /* OMP_CLAUSE_LASTPRIVATE  */
 186   4, /* OMP_CLAUSE_REDUCTION  */
 187   1, /* OMP_CLAUSE_COPYIN  */
 188   1, /* OMP_CLAUSE_COPYPRIVATE  */
 189   1, /* OMP_CLAUSE_IF  */
 190   1, /* OMP_CLAUSE_NUM_THREADS  */
 191   1, /* OMP_CLAUSE_SCHEDULE  */
 192   0, /* OMP_CLAUSE_NOWAIT  */
 193   0, /* OMP_CLAUSE_ORDERED  */
 194   0  /* OMP_CLAUSE_DEFAULT  */
 195 };
 196
 197 const char * const omp_clause_code_name[] =
 198 {
 199   "error_clause",
 200   "private",
 201   "shared",
 202   "firstprivate",
 203   "lastprivate",
 204   "reduction",
 205   "copyin",
 206   "copyprivate",
 207   "if",
 208   "num_threads",
 209   "schedule",
 210   "nowait",
 211   "ordered",
 212   "default"
 213 };
 214 \f
 215 /* Init tree.c.  */
 216
 217 void
 218 init_ttree (void)
 219 {
 220   /* Initialize the hash table of types.  */
 221   type_hash_table = htab_create_ggc (TYPE_HASH_INITIAL_SIZE, type_hash_hash,
 222                                      type_hash_eq, 0);
 223
 224   debug_expr_for_decl = htab_create_ggc (512, tree_map_hash,
 225                                          tree_map_eq, 0);
 226
 227   value_expr_for_decl = htab_create_ggc (512, tree_map_hash,
 228                                          tree_map_eq, 0);
 229   init_priority_for_decl = htab_create_ggc (512, tree_int_map_hash,
 230                                             tree_int_map_eq, 0);
 231   restrict_base_for_decl = htab_create_ggc (256, tree_map_hash,
 232                                             tree_map_eq, 0);
 233
 234   int_cst_hash_table = htab_create_ggc (1024, int_cst_hash_hash,
 235                                         int_cst_hash_eq, NULL);
 236
 237   int_cst_node = make_node (INTEGER_CST);
 238
 239   tree_contains_struct[FUNCTION_DECL][TS_DECL_NON_COMMON] = 1;
 240   tree_contains_struct[TRANSLATION_UNIT_DECL][TS_DECL_NON_COMMON] = 1;
 241   tree_contains_struct[TYPE_DECL][TS_DECL_NON_COMMON] = 1;
 242
 243
 244   tree_contains_struct[CONST_DECL][TS_DECL_COMMON] = 1;
 245   tree_contains_struct[VAR_DECL][TS_DECL_COMMON] = 1;
 246   tree_contains_struct[PARM_DECL][TS_DECL_COMMON] = 1;
 247   tree_contains_struct[RESULT_DECL][TS_DECL_COMMON] = 1;
 248   tree_contains_struct[FUNCTION_DECL][TS_DECL_COMMON] = 1;
 249   tree_contains_struct[TYPE_DECL][TS_DECL_COMMON] = 1;
 250   tree_contains_struct[TRANSLATION_UNIT_DECL][TS_DECL_COMMON] = 1;
 251   tree_contains_struct[LABEL_DECL][TS_DECL_COMMON] = 1;
 252   tree_contains_struct[FIELD_DECL][TS_DECL_COMMON] = 1;
 253
 254
 255   tree_contains_struct[CONST_DECL][TS_DECL_WRTL] = 1;
 256   tree_contains_struct[VAR_DECL][TS_DECL_WRTL] = 1;
 257   tree_contains_struct[PARM_DECL][TS_DECL_WRTL] = 1;
 258   tree_contains_struct[RESULT_DECL][TS_DECL_WRTL] = 1;
 259   tree_contains_struct[FUNCTION_DECL][TS_DECL_WRTL] = 1;
 260   tree_contains_struct[LABEL_DECL][TS_DECL_WRTL] = 1;
 261
 262   tree_contains_struct[CONST_DECL][TS_DECL_MINIMAL] = 1;
 263   tree_contains_struct[VAR_DECL][TS_DECL_MINIMAL] = 1;
 264   tree_contains_struct[PARM_DECL][TS_DECL_MINIMAL] = 1;
 265   tree_contains_struct[RESULT_DECL][TS_DECL_MINIMAL] = 1;
 266   tree_contains_struct[FUNCTION_DECL][TS_DECL_MINIMAL] = 1;
 267   tree_contains_struct[TYPE_DECL][TS_DECL_MINIMAL] = 1;
 268   tree_contains_struct[TRANSLATION_UNIT_DECL][TS_DECL_MINIMAL] = 1;
 269   tree_contains_struct[LABEL_DECL][TS_DECL_MINIMAL] = 1;
 270   tree_contains_struct[FIELD_DECL][TS_DECL_MINIMAL] = 1;
 271   tree_contains_struct[STRUCT_FIELD_TAG][TS_DECL_MINIMAL] = 1;
 272   tree_contains_struct[NAME_MEMORY_TAG][TS_DECL_MINIMAL] = 1;
 273   tree_contains_struct[SYMBOL_MEMORY_TAG][TS_DECL_MINIMAL] = 1;
 274
 275   tree_contains_struct[STRUCT_FIELD_TAG][TS_MEMORY_TAG] = 1;
 276   tree_contains_struct[NAME_MEMORY_TAG][TS_MEMORY_TAG] = 1;
 277   tree_contains_struct[SYMBOL_MEMORY_TAG][TS_MEMORY_TAG] = 1;
 278
 279   tree_contains_struct[STRUCT_FIELD_TAG][TS_STRUCT_FIELD_TAG] = 1;
 280
 281   tree_contains_struct[VAR_DECL][TS_DECL_WITH_VIS] = 1;
 282   tree_contains_struct[FUNCTION_DECL][TS_DECL_WITH_VIS] = 1;
 283   tree_contains_struct[TYPE_DECL][TS_DECL_WITH_VIS] = 1;
 284   tree_contains_struct[TRANSLATION_UNIT_DECL][TS_DECL_WITH_VIS] = 1;
 285
 286   tree_contains_struct[VAR_DECL][TS_VAR_DECL] = 1;
 287   tree_contains_struct[FIELD_DECL][TS_FIELD_DECL] = 1;
 288   tree_contains_struct[PARM_DECL][TS_PARM_DECL] = 1;
 289   tree_contains_struct[LABEL_DECL][TS_LABEL_DECL] = 1;
 290   tree_contains_struct[RESULT_DECL][TS_RESULT_DECL] = 1;
 291   tree_contains_struct[CONST_DECL][TS_CONST_DECL] = 1;
 292   tree_contains_struct[TYPE_DECL][TS_TYPE_DECL] = 1;
 293   tree_contains_struct[FUNCTION_DECL][TS_FUNCTION_DECL] = 1;
 294
 295   lang_hooks.init_ts ();
 296 }
 297
 298 \f
 299 /* The name of the object as the assembler will see it (but before any
 300    translations made by ASM_OUTPUT_LABELREF).  Often this is the same
 301    as DECL_NAME.  It is an IDENTIFIER_NODE.  */
 302 tree
 303 decl_assembler_name (tree decl)
 304 {
 305   if (!DECL_ASSEMBLER_NAME_SET_P (decl))
 306     lang_hooks.set_decl_assembler_name (decl);
 307   return DECL_WITH_VIS_CHECK (decl)->decl_with_vis.assembler_name;
 308 }
 309
 310 /* Compute the number of bytes occupied by a tree with code CODE.
 311    This function cannot be used for TREE_VEC, PHI_NODE, or STRING_CST
 312    codes, which are of variable length.  */
 313 size_t
 314 tree_code_size (enum tree_code code)
 315 {
 316   switch (TREE_CODE_CLASS (code))
 317     {
 318     case tcc_declaration:  /* A decl node */
 319       {
 320         switch (code)
 321           {
 322           case FIELD_DECL:
 323             return sizeof (struct tree_field_decl);
 324           case PARM_DECL:
 325             return sizeof (struct tree_parm_decl);
 326           case VAR_DECL:
 327             return sizeof (struct tree_var_decl);
 328           case LABEL_DECL:
 329             return sizeof (struct tree_label_decl);
 330           case RESULT_DECL:
 331             return sizeof (struct tree_result_decl);
 332           case CONST_DECL:
 333             return sizeof (struct tree_const_decl);
 334           case TYPE_DECL:
 335             return sizeof (struct tree_type_decl);
 336           case FUNCTION_DECL:
 337             return sizeof (struct tree_function_decl);
 338           case NAME_MEMORY_TAG:
 339           case SYMBOL_MEMORY_TAG:
 340             return sizeof (struct tree_memory_tag);
 341           case STRUCT_FIELD_TAG:
 342             return sizeof (struct tree_struct_field_tag);
 343           default:
 344             return sizeof (struct tree_decl_non_common);
 345           }
 346       }
 347
 348     case tcc_type:  /* a type node */
 349       return sizeof (struct tree_type);
 350
 351     case tcc_reference:   /* a reference */
 352     case tcc_expression:  /* an expression */
 353     case tcc_statement:   /* an expression with side effects */
 354     case tcc_comparison:  /* a comparison expression */
 355     case tcc_unary:       /* a unary arithmetic expression */
 356     case tcc_binary:      /* a binary arithmetic expression */
 357       return (sizeof (struct tree_exp)
 358               + (TREE_CODE_LENGTH (code) - 1) * sizeof (char *));
 359
 360     case tcc_constant:  /* a constant */
 361       switch (code)
 362         {
 363         case INTEGER_CST:       return sizeof (struct tree_int_cst);
 364         case REAL_CST:          return sizeof (struct tree_real_cst);
 365         case COMPLEX_CST:       return sizeof (struct tree_complex);
 366         case VECTOR_CST:        return sizeof (struct tree_vector);
 367         case STRING_CST:        gcc_unreachable ();
 368         default:
 369           return lang_hooks.tree_size (code);
 370         }
 371
 372     case tcc_exceptional:  /* something random, like an identifier.  */
 373       switch (code)
 374         {
 375         case IDENTIFIER_NODE:   return lang_hooks.identifier_size;
 376         case TREE_LIST:         return sizeof (struct tree_list);
 377
 378         case ERROR_MARK:
 379         case PLACEHOLDER_EXPR:  return sizeof (struct tree_common);
 380
 381         case TREE_VEC:
 382         case OMP_CLAUSE:
 383         case PHI_NODE:          gcc_unreachable ();
 384
 385         case SSA_NAME:          return sizeof (struct tree_ssa_name);
 386
 387         case STATEMENT_LIST:    return sizeof (struct tree_statement_list);
 388         case BLOCK:             return sizeof (struct tree_block);
 389         case VALUE_HANDLE:      return sizeof (struct tree_value_handle);
 390         case CONSTRUCTOR:       return sizeof (struct tree_constructor);
 391
 392         default:
 393           return lang_hooks.tree_size (code);
 394         }
 395
 396     default:
 397       gcc_unreachable ();
 398     }
 399 }
 400
 401 /* Compute the number of bytes occupied by NODE.  This routine only
 402    looks at TREE_CODE, except for PHI_NODE and TREE_VEC nodes.  */
 403 size_t
 404 tree_size (tree node)
 405 {
 406   enum tree_code code = TREE_CODE (node);
 407   switch (code)
 408     {
 409     case PHI_NODE:
 410       return (sizeof (struct tree_phi_node)
 411               + (PHI_ARG_CAPACITY (node) - 1) * sizeof (struct phi_arg_d));
 412
 413     case TREE_BINFO:
 414       return (offsetof (struct tree_binfo, base_binfos)
 415               + VEC_embedded_size (tree, BINFO_N_BASE_BINFOS (node)));
 416
 417     case TREE_VEC:
 418       return (sizeof (struct tree_vec)
 419               + (TREE_VEC_LENGTH (node) - 1) * sizeof(char *));
 420
 421     case STRING_CST:
 422       return TREE_STRING_LENGTH (node) + offsetof (struct tree_string, str) + 1;
 423
 424     case OMP_CLAUSE:
 425       return (sizeof (struct tree_omp_clause)
 426               + (omp_clause_num_ops[OMP_CLAUSE_CODE (node)] - 1)
 427                 * sizeof (tree));
 428
 429     default:
 430       return tree_code_size (code);
 431     }
 432 }
 433
 434 /* Return a newly allocated node of code CODE.  For decl and type
 435    nodes, some other fields are initialized.  The rest of the node is
 436    initialized to zero.  This function cannot be used for PHI_NODE,
 437    TREE_VEC or OMP_CLAUSE nodes, which is enforced by asserts in
 438    tree_code_size.
 439
 440    Achoo!  I got a code in the node.  */
 441
 442 tree
 443 make_node_stat (enum tree_code code MEM_STAT_DECL)
 444 {
 445   tree t;
 446   enum tree_code_class type = TREE_CODE_CLASS (code);
 447   size_t length = tree_code_size (code);
 448 #ifdef GATHER_STATISTICS
 449   tree_node_kind kind;
 450
 451   switch (type)
 452     {
 453     case tcc_declaration:  /* A decl node */
 454       kind = d_kind;
 455       break;
 456
 457     case tcc_type:  /* a type node */
 458       kind = t_kind;
 459       break;
 460
 461     case tcc_statement:  /* an expression with side effects */
 462       kind = s_kind;
 463       break;
 464
 465     case tcc_reference:  /* a reference */
 466       kind = r_kind;
 467       break;
 468
 469     case tcc_expression:  /* an expression */
 470     case tcc_comparison:  /* a comparison expression */
 471     case tcc_unary:  /* a unary arithmetic expression */
 472     case tcc_binary:  /* a binary arithmetic expression */
 473       kind = e_kind;
 474       break;
 475
 476     case tcc_constant:  /* a constant */
 477       kind = c_kind;
 478       break;
 479
 480     case tcc_exceptional:  /* something random, like an identifier.  */
 481       switch (code)
 482         {
 483         case IDENTIFIER_NODE:
 484           kind = id_kind;
 485           break;
 486
 487         case TREE_VEC:
 488           kind = vec_kind;
 489           break;
 490
 491         case TREE_BINFO:
 492           kind = binfo_kind;
 493           break;
 494
 495         case PHI_NODE:
 496           kind = phi_kind;
 497           break;
 498
 499         case SSA_NAME:
 500           kind = ssa_name_kind;
 501           break;
 502
 503         case BLOCK:
 504           kind = b_kind;
 505           break;
 506
 507         case CONSTRUCTOR:
 508           kind = constr_kind;
 509           break;
 510
 511         default:
 512           kind = x_kind;
 513           break;
 514         }
 515       break;
 516
 517     default:
 518       gcc_unreachable ();
 519     }
 520
 521   tree_node_counts[(int) kind]++;
 522   tree_node_sizes[(int) kind] += length;
 523 #endif
 524
 525   if (code == IDENTIFIER_NODE)
 526     t = ggc_alloc_zone_pass_stat (length, &tree_id_zone);
 527   else
 528     t = ggc_alloc_zone_pass_stat (length, &tree_zone);
 529
 530   memset (t, 0, length);
 531
 532   TREE_SET_CODE (t, code);
 533
 534   switch (type)
 535     {
 536     case tcc_statement:
 537       TREE_SIDE_EFFECTS (t) = 1;
 538       break;
 539
 540     case tcc_declaration:
 541       if (CODE_CONTAINS_STRUCT (code, TS_DECL_WITH_VIS))
 542         DECL_IN_SYSTEM_HEADER (t) = in_system_header;
 543       if (CODE_CONTAINS_STRUCT (code, TS_DECL_COMMON))
 544         {
 545           if (code != FUNCTION_DECL)
 546             DECL_ALIGN (t) = 1;
 547           DECL_USER_ALIGN (t) = 0;
 548           /* We have not yet computed the alias set for this declaration.  */
 549           DECL_POINTER_ALIAS_SET (t) = -1;
 550         }
 551       DECL_SOURCE_LOCATION (t) = input_location;
 552       DECL_UID (t) = next_decl_uid++;
 553
 554       break;
 555
 556     case tcc_type:
 557       TYPE_UID (t) = next_type_uid++;
 558       TYPE_ALIGN (t) = BITS_PER_UNIT;
 559       TYPE_USER_ALIGN (t) = 0;
 560       TYPE_MAIN_VARIANT (t) = t;
 561
 562       /* Default to no attributes for type, but let target change that.  */
 563       TYPE_ATTRIBUTES (t) = NULL_TREE;
 564       targetm.set_default_type_attributes (t);
 565
 566       /* We have not yet computed the alias set for this type.  */
 567       TYPE_ALIAS_SET (t) = -1;
 568       break;
 569
 570     case tcc_constant:
 571       TREE_CONSTANT (t) = 1;
 572       TREE_INVARIANT (t) = 1;
 573       break;
 574
 575     case tcc_expression:
 576       switch (code)
 577         {
 578         case INIT_EXPR:
 579         case MODIFY_EXPR:
 580         case VA_ARG_EXPR:
 581         case PREDECREMENT_EXPR:
 582         case PREINCREMENT_EXPR:
 583         case POSTDECREMENT_EXPR:
 584         case POSTINCREMENT_EXPR:
 585           /* All of these have side-effects, no matter what their
 586              operands are.  */
 587           TREE_SIDE_EFFECTS (t) = 1;
 588           break;
 589
 590         default:
 591           break;
 592         }
 593       break;
 594
 595     default:
 596       /* Other classes need no special treatment.  */
 597       break;
 598     }
 599
 600   return t;
 601 }
 602 \f
 603 /* Return a new node with the same contents as NODE except that its
 604    TREE_CHAIN is zero and it has a fresh uid.  */
 605
 606 tree
 607 copy_node_stat (tree node MEM_STAT_DECL)
 608 {
 609   tree t;
 610   enum tree_code code = TREE_CODE (node);
 611   size_t length;
 612
 613   gcc_assert (code != STATEMENT_LIST);
 614
 615   length = tree_size (node);
 616   t = ggc_alloc_zone_pass_stat (length, &tree_zone);
 617   memcpy (t, node, length);
 618
 619   TREE_CHAIN (t) = 0;
 620   TREE_ASM_WRITTEN (t) = 0;
 621   TREE_VISITED (t) = 0;
 622   t->common.ann = 0;
 623
 624   if (TREE_CODE_CLASS (code) == tcc_declaration)
 625     {
 626       DECL_UID (t) = next_decl_uid++;
 627       if ((TREE_CODE (node) == PARM_DECL || TREE_CODE (node) == VAR_DECL)
 628           && DECL_HAS_VALUE_EXPR_P (node))
 629         {
 630           SET_DECL_VALUE_EXPR (t, DECL_VALUE_EXPR (node));
 631           DECL_HAS_VALUE_EXPR_P (t) = 1;
 632         }
 633       if (TREE_CODE (node) == VAR_DECL && DECL_HAS_INIT_PRIORITY_P (node))
 634         {
 635           SET_DECL_INIT_PRIORITY (t, DECL_INIT_PRIORITY (node));
 636           DECL_HAS_INIT_PRIORITY_P (t) = 1;
 637         }
 638       if (TREE_CODE (node) == VAR_DECL && DECL_BASED_ON_RESTRICT_P (node))
 639         {
 640           SET_DECL_RESTRICT_BASE (t, DECL_GET_RESTRICT_BASE (node));
 641           DECL_BASED_ON_RESTRICT_P (t) = 1;
 642         }
 643     }
 644   else if (TREE_CODE_CLASS (code) == tcc_type)
 645     {
 646       TYPE_UID (t) = next_type_uid++;
 647       /* The following is so that the debug code for
 648          the copy is different from the original type.
 649          The two statements usually duplicate each other
 650          (because they clear fields of the same union),
 651          but the optimizer should catch that.  */
 652       TYPE_SYMTAB_POINTER (t) = 0;
 653       TYPE_SYMTAB_ADDRESS (t) = 0;
 654
 655       /* Do not copy the values cache.  */
 656       if (TYPE_CACHED_VALUES_P(t))
 657         {
 658           TYPE_CACHED_VALUES_P (t) = 0;
 659           TYPE_CACHED_VALUES (t) = NULL_TREE;
 660         }
 661     }
 662
 663   return t;
 664 }
 665
 666 /* Return a copy of a chain of nodes, chained through the TREE_CHAIN field.
 667    For example, this can copy a list made of TREE_LIST nodes.  */
 668
 669 tree
 670 copy_list (tree list)
 671 {
 672   tree head;
 673   tree prev, next;
 674
 675   if (list == 0)
 676     return 0;
 677
 678   head = prev = copy_node (list);
 679   next = TREE_CHAIN (list);
 680   while (next)
 681     {
 682       TREE_CHAIN (prev) = copy_node (next);
 683       prev = TREE_CHAIN (prev);
 684       next = TREE_CHAIN (next);
 685     }
 686   return head;
 687 }
 688
 689 \f
 690 /* Create an INT_CST node with a LOW value sign extended.  */
 691
 692 tree
 693 build_int_cst (tree type, HOST_WIDE_INT low)
 694 {
 695   return build_int_cst_wide (type, low, low < 0 ? -1 : 0);
 696 }
 697
 698 /* Create an INT_CST node with a LOW value zero extended.  */
 699
 700 tree
 701 build_int_cstu (tree type, unsigned HOST_WIDE_INT low)
 702 {
 703   return build_int_cst_wide (type, low, 0);
 704 }
 705
 706 /* Create an INT_CST node with a LOW value in TYPE.  The value is sign extended
 707    if it is negative.  This function is similar to build_int_cst, but
 708    the extra bits outside of the type precision are cleared.  Constants
 709    with these extra bits may confuse the fold so that it detects overflows
 710    even in cases when they do not occur, and in general should be avoided.
 711    We cannot however make this a default behavior of build_int_cst without
 712    more intrusive changes, since there are parts of gcc that rely on the extra
 713    precision of the integer constants.  */
 714
 715 tree
 716 build_int_cst_type (tree type, HOST_WIDE_INT low)
 717 {
 718   unsigned HOST_WIDE_INT val = (unsigned HOST_WIDE_INT) low;
 719   unsigned HOST_WIDE_INT hi, mask;
 720   unsigned bits;
 721   bool signed_p;
 722   bool negative;
 723
 724   if (!type)
 725     type = integer_type_node;
 726
 727   bits = TYPE_PRECISION (type);
 728   signed_p = !TYPE_UNSIGNED (type);
 729
 730   if (bits >= HOST_BITS_PER_WIDE_INT)
 731     negative = (low < 0);
 732   else
 733     {
 734       /* If the sign bit is inside precision of LOW, use it to determine
 735          the sign of the constant.  */
 736       negative = ((val >> (bits - 1)) & 1) != 0;
 737
 738       /* Mask out the bits outside of the precision of the constant.  */
 739       mask = (((unsigned HOST_WIDE_INT) 2) << (bits - 1)) - 1;
 740
 741       if (signed_p && negative)
 742         val |= ~mask;
 743       else
 744         val &= mask;
 745     }
 746
 747   /* Determine the high bits.  */
 748   hi = (negative ? ~(unsigned HOST_WIDE_INT) 0 : 0);
 749
 750   /* For unsigned type we need to mask out the bits outside of the type
 751      precision.  */
 752   if (!signed_p)
 753     {
 754       if (bits <= HOST_BITS_PER_WIDE_INT)
 755         hi = 0;
 756       else
 757         {
 758           bits -= HOST_BITS_PER_WIDE_INT;
 759           mask = (((unsigned HOST_WIDE_INT) 2) << (bits - 1)) - 1;
 760           hi &= mask;
 761         }
 762     }
 763
 764   return build_int_cst_wide (type, val, hi);
 765 }
 766
 767 /* These are the hash table functions for the hash table of INTEGER_CST
 768    nodes of a sizetype.  */
 769
 770 /* Return the hash code code X, an INTEGER_CST.  */
 771
 772 static hashval_t
 773 int_cst_hash_hash (const void *x)
 774 {
 775   tree t = (tree) x;
 776
 777   return (TREE_INT_CST_HIGH (t) ^ TREE_INT_CST_LOW (t)
 778           ^ htab_hash_pointer (TREE_TYPE (t)));
 779 }
 780
 781 /* Return nonzero if the value represented by *X (an INTEGER_CST tree node)
 782    is the same as that given by *Y, which is the same.  */
 783
 784 static int
 785 int_cst_hash_eq (const void *x, const void *y)
 786 {
 787   tree xt = (tree) x;
 788   tree yt = (tree) y;
 789
 790   return (TREE_TYPE (xt) == TREE_TYPE (yt)
 791           && TREE_INT_CST_HIGH (xt) == TREE_INT_CST_HIGH (yt)
 792           && TREE_INT_CST_LOW (xt) == TREE_INT_CST_LOW (yt));
 793 }
 794
 795 /* Create an INT_CST node of TYPE and value HI:LOW.  If TYPE is NULL,
 796    integer_type_node is used.  The returned node is always shared.
 797    For small integers we use a per-type vector cache, for larger ones
 798    we use a single hash table.  */
 799
 800 tree
 801 build_int_cst_wide (tree type, unsigned HOST_WIDE_INT low, HOST_WIDE_INT hi)
 802 {
 803   tree t;
 804   int ix = -1;
 805   int limit = 0;
 806
 807   if (!type)
 808     type = integer_type_node;
 809
 810   switch (TREE_CODE (type))
 811     {
 812     case POINTER_TYPE:
 813     case REFERENCE_TYPE:
 814       /* Cache NULL pointer.  */
 815       if (!hi && !low)
 816         {
 817           limit = 1;
 818           ix = 0;
 819         }
 820       break;
 821
 822     case BOOLEAN_TYPE:
 823       /* Cache false or true.  */
 824       limit = 2;
 825       if (!hi && low < 2)
 826         ix = low;
 827       break;
 828
 829     case INTEGER_TYPE:
 830     case OFFSET_TYPE:
 831       if (TYPE_UNSIGNED (type))
 832         {
 833           /* Cache 0..N */
 834           limit = INTEGER_SHARE_LIMIT;
 835           if (!hi && low < (unsigned HOST_WIDE_INT)INTEGER_SHARE_LIMIT)
 836             ix = low;
 837         }
 838       else
 839         {
 840           /* Cache -1..N */
 841           limit = INTEGER_SHARE_LIMIT + 1;
 842           if (!hi && low < (unsigned HOST_WIDE_INT)INTEGER_SHARE_LIMIT)
 843             ix = low + 1;
 844           else if (hi == -1 && low == -(unsigned HOST_WIDE_INT)1)
 845             ix = 0;
 846         }
 847       break;
 848     default:
 849       break;
 850     }
 851
 852   if (ix >= 0)
 853     {
 854       /* Look for it in the type's vector of small shared ints.  */
 855       if (!TYPE_CACHED_VALUES_P (type))
 856         {
 857           TYPE_CACHED_VALUES_P (type) = 1;
 858           TYPE_CACHED_VALUES (type) = make_tree_vec (limit);
 859         }
 860
 861       t = TREE_VEC_ELT (TYPE_CACHED_VALUES (type), ix);
 862       if (t)
 863         {
 864           /* Make sure no one is clobbering the shared constant.  */
 865           gcc_assert (TREE_TYPE (t) == type);
 866           gcc_assert (TREE_INT_CST_LOW (t) == low);
 867           gcc_assert (TREE_INT_CST_HIGH (t) == hi);
 868         }
 869       else
 870         {
 871           /* Create a new shared int.  */
 872           t = make_node (INTEGER_CST);
 873
 874           TREE_INT_CST_LOW (t) = low;
 875           TREE_INT_CST_HIGH (t) = hi;
 876           TREE_TYPE (t) = type;
 877
 878           TREE_VEC_ELT (TYPE_CACHED_VALUES (type), ix) = t;
 879         }
 880     }
 881   else
 882     {
 883       /* Use the cache of larger shared ints.  */
 884       void **slot;
 885
 886       TREE_INT_CST_LOW (int_cst_node) = low;
 887       TREE_INT_CST_HIGH (int_cst_node) = hi;
 888       TREE_TYPE (int_cst_node) = type;
 889
 890       slot = htab_find_slot (int_cst_hash_table, int_cst_node, INSERT);
 891       t = *slot;
 892       if (!t)
 893         {
 894           /* Insert this one into the hash table.  */
 895           t = int_cst_node;
 896           *slot = t;
 897           /* Make a new node for next time round.  */
 898           int_cst_node = make_node (INTEGER_CST);
 899         }
 900     }
 901
 902   return t;
 903 }
 904
 905 /* Builds an integer constant in TYPE such that lowest BITS bits are ones
 906    and the rest are zeros.  */
 907
 908 tree
 909 build_low_bits_mask (tree type, unsigned bits)
 910 {
 911   unsigned HOST_WIDE_INT low;
 912   HOST_WIDE_INT high;
 913   unsigned HOST_WIDE_INT all_ones = ~(unsigned HOST_WIDE_INT) 0;
 914
 915   gcc_assert (bits <= TYPE_PRECISION (type));
 916
 917   if (bits == TYPE_PRECISION (type)
 918       && !TYPE_UNSIGNED (type))
 919     {
 920       /* Sign extended all-ones mask.  */
 921       low = all_ones;
 922       high = -1;
 923     }
 924   else if (bits <= HOST_BITS_PER_WIDE_INT)
 925     {
 926       low = all_ones >> (HOST_BITS_PER_WIDE_INT - bits);
 927       high = 0;
 928     }
 929   else
 930     {
 931       bits -= HOST_BITS_PER_WIDE_INT;
 932       low = all_ones;
 933       high = all_ones >> (HOST_BITS_PER_WIDE_INT - bits);
 934     }
 935
 936   return build_int_cst_wide (type, low, high);
 937 }
 938
 939 /* Checks that X is integer constant that can be expressed in (unsigned)
 940    HOST_WIDE_INT without loss of precision.  */
 941
 942 bool
 943 cst_and_fits_in_hwi (tree x)
 944 {
 945   if (TREE_CODE (x) != INTEGER_CST)
 946     return false;
 947
 948   if (TYPE_PRECISION (TREE_TYPE (x)) > HOST_BITS_PER_WIDE_INT)
 949     return false;
 950
 951   return (TREE_INT_CST_HIGH (x) == 0
 952           || TREE_INT_CST_HIGH (x) == -1);
 953 }
 954
 955 /* Return a new VECTOR_CST node whose type is TYPE and whose values
 956    are in a list pointed to by VALS.  */
 957
 958 tree
 959 build_vector (tree type, tree vals)
 960 {
 961   tree v = make_node (VECTOR_CST);
 962   int over1 = 0, over2 = 0;
 963   tree link;
 964
 965   TREE_VECTOR_CST_ELTS (v) = vals;
 966   TREE_TYPE (v) = type;
 967
 968   /* Iterate through elements and check for overflow.  */
 969   for (link = vals; link; link = TREE_CHAIN (link))
 970     {
 971       tree value = TREE_VALUE (link);
 972
 973       over1 |= TREE_OVERFLOW (value);
 974       over2 |= TREE_CONSTANT_OVERFLOW (value);
 975     }
 976
 977   TREE_OVERFLOW (v) = over1;
 978   TREE_CONSTANT_OVERFLOW (v) = over2;
 979
 980   return v;
 981 }
 982
 983 /* Return a new VECTOR_CST node whose type is TYPE and whose values
 984    are extracted from V, a vector of CONSTRUCTOR_ELT.  */
 985
 986 tree
 987 build_vector_from_ctor (tree type, VEC(constructor_elt,gc) *v)
 988 {
 989   tree list = NULL_TREE;
 990   unsigned HOST_WIDE_INT idx;
 991   tree value;
 992
 993   FOR_EACH_CONSTRUCTOR_VALUE (v, idx, value)
 994     list = tree_cons (NULL_TREE, value, list);
 995   return build_vector (type, nreverse (list));
 996 }
 997
 998 /* Return a new CONSTRUCTOR node whose type is TYPE and whose values
 999    are in the VEC pointed to by VALS.  */
1000 tree
1001 build_constructor (tree type, VEC(constructor_elt,gc) *vals)
1002 {
1003   tree c = make_node (CONSTRUCTOR);
1004   TREE_TYPE (c) = type;
1005   CONSTRUCTOR_ELTS (c) = vals;
1006   return c;
1007 }
1008
1009 /* Build a CONSTRUCTOR node made of a single initializer, with the specified
1010    INDEX and VALUE.  */
1011 tree
1012 build_constructor_single (tree type, tree index, tree value)
1013 {
1014   VEC(constructor_elt,gc) *v;
1015   constructor_elt *elt;
1016   tree t;
1017
1018   v = VEC_alloc (constructor_elt, gc, 1);
1019   elt = VEC_quick_push (constructor_elt, v, NULL);
1020   elt->index = index;
1021   elt->value = value;
1022
1023   t = build_constructor (type, v);
1024   TREE_CONSTANT (t) = TREE_CONSTANT (value);
1025   return t;
1026 }
1027
1028
1029 /* Return a new CONSTRUCTOR node whose type is TYPE and whose values
1030    are in a list pointed to by VALS.  */
1031 tree
1032 build_constructor_from_list (tree type, tree vals)
1033 {
1034   tree t, val;
1035   VEC(constructor_elt,gc) *v = NULL;
1036   bool constant_p = true;
1037
1038   if (vals)
1039     {
1040       v = VEC_alloc (constructor_elt, gc, list_length (vals));
1041       for (t = vals; t; t = TREE_CHAIN (t))
1042         {
1043           constructor_elt *elt = VEC_quick_push (constructor_elt, v, NULL);
1044           val = TREE_VALUE (t);
1045           elt->index = TREE_PURPOSE (t);
1046           elt->value = val;
1047           if (!TREE_CONSTANT (val))
1048             constant_p = false;
1049         }
1050     }
1051
1052   t = build_constructor (type, v);
1053   TREE_CONSTANT (t) = constant_p;
1054   return t;
1055 }
1056
1057
1058 /* Return a new REAL_CST node whose type is TYPE and value is D.  */
1059
1060 tree
1061 build_real (tree type, REAL_VALUE_TYPE d)
1062 {
1063   tree v;
1064   REAL_VALUE_TYPE *dp;
1065   int overflow = 0;
1066
1067   /* ??? Used to check for overflow here via CHECK_FLOAT_TYPE.
1068      Consider doing it via real_convert now.  */
1069
1070   v = make_node (REAL_CST);
1071   dp = ggc_alloc (sizeof (REAL_VALUE_TYPE));
1072   memcpy (dp, &d, sizeof (REAL_VALUE_TYPE));
1073
1074   TREE_TYPE (v) = type;
1075   TREE_REAL_CST_PTR (v) = dp;
1076   TREE_OVERFLOW (v) = TREE_CONSTANT_OVERFLOW (v) = overflow;
1077   return v;
1078 }
1079
1080 /* Return a new REAL_CST node whose type is TYPE
1081    and whose value is the integer value of the INTEGER_CST node I.  */
1082
1083 REAL_VALUE_TYPE
1084 real_value_from_int_cst (tree type, tree i)
1085 {
1086   REAL_VALUE_TYPE d;
1087
1088   /* Clear all bits of the real value type so that we can later do
1089      bitwise comparisons to see if two values are the same.  */
1090   memset (&d, 0, sizeof d);
1091
1092   real_from_integer (&d, type ? TYPE_MODE (type) : VOIDmode,
1093                      TREE_INT_CST_LOW (i), TREE_INT_CST_HIGH (i),
1094                      TYPE_UNSIGNED (TREE_TYPE (i)));
1095   return d;
1096 }
1097
1098 /* Given a tree representing an integer constant I, return a tree
1099    representing the same value as a floating-point constant of type TYPE.  */
1100
1101 tree
1102 build_real_from_int_cst (tree type, tree i)
1103 {
1104   tree v;
1105   int overflow = TREE_OVERFLOW (i);
1106
1107   v = build_real (type, real_value_from_int_cst (type, i));
1108
1109   TREE_OVERFLOW (v) |= overflow;
1110   TREE_CONSTANT_OVERFLOW (v) |= overflow;
1111   return v;
1112 }
1113
1114 /* Return a newly constructed STRING_CST node whose value is
1115    the LEN characters at STR.
1116    The TREE_TYPE is not initialized.  */
1117
1118 tree
1119 build_string (int len, const char *str)
1120 {
1121   tree s;
1122   size_t length;
1123
1124   /* Do not waste bytes provided by padding of struct tree_string.  */
1125   length = len + offsetof (struct tree_string, str) + 1;
1126
1127 #ifdef GATHER_STATISTICS
1128   tree_node_counts[(int) c_kind]++;
1129   tree_node_sizes[(int) c_kind] += length;
1130 #endif
1131
1132   s = ggc_alloc_tree (length);
1133
1134   memset (s, 0, sizeof (struct tree_common));
1135   TREE_SET_CODE (s, STRING_CST);
1136   TREE_CONSTANT (s) = 1;
1137   TREE_INVARIANT (s) = 1;
1138   TREE_STRING_LENGTH (s) = len;
1139   memcpy ((char *) TREE_STRING_POINTER (s), str, len);
1140   ((char *) TREE_STRING_POINTER (s))[len] = '\0';
1141
1142   return s;
1143 }
1144
1145 /* Return a newly constructed COMPLEX_CST node whose value is
1146    specified by the real and imaginary parts REAL and IMAG.
1147    Both REAL and IMAG should be constant nodes.  TYPE, if specified,
1148    will be the type of the COMPLEX_CST; otherwise a new type will be made.  */
1149
1150 tree
1151 build_complex (tree type, tree real, tree imag)
1152 {
1153   tree t = make_node (COMPLEX_CST);
1154
1155   TREE_REALPART (t) = real;
1156   TREE_IMAGPART (t) = imag;
1157   TREE_TYPE (t) = type ? type : build_complex_type (TREE_TYPE (real));
1158   TREE_OVERFLOW (t) = TREE_OVERFLOW (real) | TREE_OVERFLOW (imag);
1159   TREE_CONSTANT_OVERFLOW (t)
1160     = TREE_CONSTANT_OVERFLOW (real) | TREE_CONSTANT_OVERFLOW (imag);
1161   return t;
1162 }
1163
1164 /* Return a constant of arithmetic type TYPE which is the
1165    multiplicative identity of the set TYPE.  */
1166
1167 tree
1168 build_one_cst (tree type)
1169 {
1170   switch (TREE_CODE (type))
1171     {
1172     case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
1173     case POINTER_TYPE: case REFERENCE_TYPE:
1174     case OFFSET_TYPE:
1175       return build_int_cst (type, 1);
1176
1177     case REAL_TYPE:
1178       return build_real (type, dconst1);
1179
1180     case VECTOR_TYPE:
1181       {
1182         tree scalar, cst;
1183         int i;
1184
1185         scalar = build_one_cst (TREE_TYPE (type));
1186
1187         /* Create 'vect_cst_ = {cst,cst,...,cst}'  */
1188         cst = NULL_TREE;
1189         for (i = TYPE_VECTOR_SUBPARTS (type); --i >= 0; )
1190           cst = tree_cons (NULL_TREE, scalar, cst);
1191
1192         return build_vector (type, cst);
1193       }
1194
1195     case COMPLEX_TYPE:
1196       return build_complex (type,
1197                             build_one_cst (TREE_TYPE (type)),
1198                             fold_convert (TREE_TYPE (type), integer_zero_node));
1199
1200     default:
1201       gcc_unreachable ();
1202     }
1203 }
1204
1205 /* Build a BINFO with LEN language slots.  */
1206
1207 tree
1208 make_tree_binfo_stat (unsigned base_binfos MEM_STAT_DECL)
1209 {
1210   tree t;
1211   size_t length = (offsetof (struct tree_binfo, base_binfos)
1212                    + VEC_embedded_size (tree, base_binfos));
1213
1214 #ifdef GATHER_STATISTICS
1215   tree_node_counts[(int) binfo_kind]++;
1216   tree_node_sizes[(int) binfo_kind] += length;
1217 #endif
1218
1219   t = ggc_alloc_zone_pass_stat (length, &tree_zone);
1220
1221   memset (t, 0, offsetof (struct tree_binfo, base_binfos));
1222
1223   TREE_SET_CODE (t, TREE_BINFO);
1224
1225   VEC_embedded_init (tree, BINFO_BASE_BINFOS (t), base_binfos);
1226
1227   return t;
1228 }
1229
1230
1231 /* Build a newly constructed TREE_VEC node of length LEN.  */
1232
1233 tree
1234 make_tree_vec_stat (int len MEM_STAT_DECL)
1235 {
1236   tree t;
1237   int length = (len - 1) * sizeof (tree) + sizeof (struct tree_vec);
1238
1239 #ifdef GATHER_STATISTICS
1240   tree_node_counts[(int) vec_kind]++;
1241   tree_node_sizes[(int) vec_kind] += length;
1242 #endif
1243
1244   t = ggc_alloc_zone_pass_stat (length, &tree_zone);
1245
1246   memset (t, 0, length);
1247
1248   TREE_SET_CODE (t, TREE_VEC);
1249   TREE_VEC_LENGTH (t) = len;
1250
1251   return t;
1252 }
1253 \f
1254 /* Return 1 if EXPR is the integer constant zero or a complex constant
1255    of zero.  */
1256
1257 int
1258 integer_zerop (tree expr)
1259 {
1260   STRIP_NOPS (expr);
1261
1262   return ((TREE_CODE (expr) == INTEGER_CST
1263            && TREE_INT_CST_LOW (expr) == 0
1264            && TREE_INT_CST_HIGH (expr) == 0)
1265           || (TREE_CODE (expr) == COMPLEX_CST
1266               && integer_zerop (TREE_REALPART (expr))
1267               && integer_zerop (TREE_IMAGPART (expr))));
1268 }
1269
1270 /* Return 1 if EXPR is the integer constant one or the corresponding
1271    complex constant.  */
1272
1273 int
1274 integer_onep (tree expr)
1275 {
1276   STRIP_NOPS (expr);
1277
1278   return ((TREE_CODE (expr) == INTEGER_CST
1279            && TREE_INT_CST_LOW (expr) == 1
1280            && TREE_INT_CST_HIGH (expr) == 0)
1281           || (TREE_CODE (expr) == COMPLEX_CST
1282               && integer_onep (TREE_REALPART (expr))
1283               && integer_zerop (TREE_IMAGPART (expr))));
1284 }
1285
1286 /* Return 1 if EXPR is an integer containing all 1's in as much precision as
1287    it contains.  Likewise for the corresponding complex constant.  */
1288
1289 int
1290 integer_all_onesp (tree expr)
1291 {
1292   int prec;
1293   int uns;
1294
1295   STRIP_NOPS (expr);
1296
1297   if (TREE_CODE (expr) == COMPLEX_CST
1298       && integer_all_onesp (TREE_REALPART (expr))
1299       && integer_zerop (TREE_IMAGPART (expr)))
1300     return 1;
1301
1302   else if (TREE_CODE (expr) != INTEGER_CST)
1303     return 0;
1304
1305   uns = TYPE_UNSIGNED (TREE_TYPE (expr));
1306   if (TREE_INT_CST_LOW (expr) == ~(unsigned HOST_WIDE_INT) 0
1307       && TREE_INT_CST_HIGH (expr) == -1)
1308     return 1;
1309   if (!uns)
1310     return 0;
1311
1312   /* Note that using TYPE_PRECISION here is wrong.  We care about the
1313      actual bits, not the (arbitrary) range of the type.  */
1314   prec = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (expr)));
1315   if (prec >= HOST_BITS_PER_WIDE_INT)
1316     {
1317       HOST_WIDE_INT high_value;
1318       int shift_amount;
1319
1320       shift_amount = prec - HOST_BITS_PER_WIDE_INT;
1321
1322       /* Can not handle precisions greater than twice the host int size.  */
1323       gcc_assert (shift_amount <= HOST_BITS_PER_WIDE_INT);
1324       if (shift_amount == HOST_BITS_PER_WIDE_INT)
1325         /* Shifting by the host word size is undefined according to the ANSI
1326            standard, so we must handle this as a special case.  */
1327         high_value = -1;
1328       else
1329         high_value = ((HOST_WIDE_INT) 1 << shift_amount) - 1;
1330
1331       return (TREE_INT_CST_LOW (expr) == ~(unsigned HOST_WIDE_INT) 0
1332               && TREE_INT_CST_HIGH (expr) == high_value);
1333     }
1334   else
1335     return TREE_INT_CST_LOW (expr) == ((unsigned HOST_WIDE_INT) 1 << prec) - 1;
1336 }
1337
1338 /* Return 1 if EXPR is an integer constant that is a power of 2 (i.e., has only
1339    one bit on).  */
1340
1341 int
1342 integer_pow2p (tree expr)
1343 {
1344   int prec;
1345   HOST_WIDE_INT high, low;
1346
1347   STRIP_NOPS (expr);
1348
1349   if (TREE_CODE (expr) == COMPLEX_CST
1350       && integer_pow2p (TREE_REALPART (expr))
1351       && integer_zerop (TREE_IMAGPART (expr)))
1352     return 1;
1353
1354   if (TREE_CODE (expr) != INTEGER_CST)
1355     return 0;
1356
1357   prec = (POINTER_TYPE_P (TREE_TYPE (expr))
1358           ? POINTER_SIZE : TYPE_PRECISION (TREE_TYPE (expr)));
1359   high = TREE_INT_CST_HIGH (expr);
1360   low = TREE_INT_CST_LOW (expr);
1361
1362   /* First clear all bits that are beyond the type's precision in case
1363      we've been sign extended.  */
1364
1365   if (prec == 2 * HOST_BITS_PER_WIDE_INT)
1366     ;
1367   else if (prec > HOST_BITS_PER_WIDE_INT)
1368     high &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
1369   else
1370     {
1371       high = 0;
1372       if (prec < HOST_BITS_PER_WIDE_INT)
1373         low &= ~((HOST_WIDE_INT) (-1) << prec);
1374     }
1375
1376   if (high == 0 && low == 0)
1377     return 0;
1378
1379   return ((high == 0 && (low & (low - 1)) == 0)
1380           || (low == 0 && (high & (high - 1)) == 0));
1381 }
1382
1383 /* Return 1 if EXPR is an integer constant other than zero or a
1384    complex constant other than zero.  */
1385
1386 int
1387 integer_nonzerop (tree expr)
1388 {
1389   STRIP_NOPS (expr);
1390
1391   return ((TREE_CODE (expr) == INTEGER_CST
1392            && (TREE_INT_CST_LOW (expr) != 0
1393                || TREE_INT_CST_HIGH (expr) != 0))
1394           || (TREE_CODE (expr) == COMPLEX_CST
1395               && (integer_nonzerop (TREE_REALPART (expr))
1396                   || integer_nonzerop (TREE_IMAGPART (expr)))));
1397 }
1398
1399 /* Return the power of two represented by a tree node known to be a
1400    power of two.  */
1401
1402 int
1403 tree_log2 (tree expr)
1404 {
1405   int prec;
1406   HOST_WIDE_INT high, low;
1407
1408   STRIP_NOPS (expr);
1409
1410   if (TREE_CODE (expr) == COMPLEX_CST)
1411     return tree_log2 (TREE_REALPART (expr));
1412
1413   prec = (POINTER_TYPE_P (TREE_TYPE (expr))
1414           ? POINTER_SIZE : TYPE_PRECISION (TREE_TYPE (expr)));
1415
1416   high = TREE_INT_CST_HIGH (expr);
1417   low = TREE_INT_CST_LOW (expr);
1418
1419   /* First clear all bits that are beyond the type's precision in case
1420      we've been sign extended.  */
1421
1422   if (prec == 2 * HOST_BITS_PER_WIDE_INT)
1423     ;
1424   else if (prec > HOST_BITS_PER_WIDE_INT)
1425     high &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
1426   else
1427     {
1428       high = 0;
1429       if (prec < HOST_BITS_PER_WIDE_INT)
1430         low &= ~((HOST_WIDE_INT) (-1) << prec);
1431     }
1432
1433   return (high != 0 ? HOST_BITS_PER_WIDE_INT + exact_log2 (high)
1434           : exact_log2 (low));
1435 }
1436
1437 /* Similar, but return the largest integer Y such that 2 ** Y is less
1438    than or equal to EXPR.  */
1439
1440 int
1441 tree_floor_log2 (tree expr)
1442 {
1443   int prec;
1444   HOST_WIDE_INT high, low;
1445
1446   STRIP_NOPS (expr);
1447
1448   if (TREE_CODE (expr) == COMPLEX_CST)
1449     return tree_log2 (TREE_REALPART (expr));
1450
1451   prec = (POINTER_TYPE_P (TREE_TYPE (expr))
1452           ? POINTER_SIZE : TYPE_PRECISION (TREE_TYPE (expr)));
1453
1454   high = TREE_INT_CST_HIGH (expr);
1455   low = TREE_INT_CST_LOW (expr);
1456
1457   /* First clear all bits that are beyond the type's precision in case
1458      we've been sign extended.  Ignore if type's precision hasn't been set
1459      since what we are doing is setting it.  */
1460
1461   if (prec == 2 * HOST_BITS_PER_WIDE_INT || prec == 0)
1462     ;
1463   else if (prec > HOST_BITS_PER_WIDE_INT)
1464     high &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
1465   else
1466     {
1467       high = 0;
1468       if (prec < HOST_BITS_PER_WIDE_INT)
1469         low &= ~((HOST_WIDE_INT) (-1) << prec);
1470     }
1471
1472   return (high != 0 ? HOST_BITS_PER_WIDE_INT + floor_log2 (high)
1473           : floor_log2 (low));
1474 }
1475
1476 /* Return 1 if EXPR is the real constant zero.  */
1477
1478 int
1479 real_zerop (tree expr)
1480 {
1481   STRIP_NOPS (expr);
1482
1483   return ((TREE_CODE (expr) == REAL_CST
1484            && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst0))
1485           || (TREE_CODE (expr) == COMPLEX_CST
1486               && real_zerop (TREE_REALPART (expr))
1487               && real_zerop (TREE_IMAGPART (expr))));
1488 }
1489
1490 /* Return 1 if EXPR is the real constant one in real or complex form.  */
1491
1492 int
1493 real_onep (tree expr)
1494 {
1495   STRIP_NOPS (expr);
1496
1497   return ((TREE_CODE (expr) == REAL_CST
1498            && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst1))
1499           || (TREE_CODE (expr) == COMPLEX_CST
1500               && real_onep (TREE_REALPART (expr))
1501               && real_zerop (TREE_IMAGPART (expr))));
1502 }
1503
1504 /* Return 1 if EXPR is the real constant two.  */
1505
1506 int
1507 real_twop (tree expr)
1508 {
1509   STRIP_NOPS (expr);
1510
1511   return ((TREE_CODE (expr) == REAL_CST
1512            && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst2))
1513           || (TREE_CODE (expr) == COMPLEX_CST
1514               && real_twop (TREE_REALPART (expr))
1515               && real_zerop (TREE_IMAGPART (expr))));
1516 }
1517
1518 /* Return 1 if EXPR is the real constant minus one.  */
1519
1520 int
1521 real_minus_onep (tree expr)
1522 {
1523   STRIP_NOPS (expr);
1524
1525   return ((TREE_CODE (expr) == REAL_CST
1526            && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconstm1))
1527           || (TREE_CODE (expr) == COMPLEX_CST
1528               && real_minus_onep (TREE_REALPART (expr))
1529               && real_zerop (TREE_IMAGPART (expr))));
1530 }
1531
1532 /* Nonzero if EXP is a constant or a cast of a constant.  */
1533
1534 int
1535 really_constant_p (tree exp)
1536 {
1537   /* This is not quite the same as STRIP_NOPS.  It does more.  */
1538   while (TREE_CODE (exp) == NOP_EXPR
1539          || TREE_CODE (exp) == CONVERT_EXPR
1540          || TREE_CODE (exp) == NON_LVALUE_EXPR)
1541     exp = TREE_OPERAND (exp, 0);
1542   return TREE_CONSTANT (exp);
1543 }
1544 \f
1545 /* Return first list element whose TREE_VALUE is ELEM.
1546    Return 0 if ELEM is not in LIST.  */
1547
1548 tree
1549 value_member (tree elem, tree list)
1550 {
1551   while (list)
1552     {
1553       if (elem == TREE_VALUE (list))
1554         return list;
1555       list = TREE_CHAIN (list);
1556     }
1557   return NULL_TREE;
1558 }
1559
1560 /* Return first list element whose TREE_PURPOSE is ELEM.
1561    Return 0 if ELEM is not in LIST.  */
1562
1563 tree
1564 purpose_member (tree elem, tree list)
1565 {
1566   while (list)
1567     {
1568       if (elem == TREE_PURPOSE (list))
1569         return list;
1570       list = TREE_CHAIN (list);
1571     }
1572   return NULL_TREE;
1573 }
1574
1575 /* Return nonzero if ELEM is part of the chain CHAIN.  */
1576
1577 int
1578 chain_member (tree elem, tree chain)
1579 {
1580   while (chain)
1581     {
1582       if (elem == chain)
1583         return 1;
1584       chain = TREE_CHAIN (chain);
1585     }
1586
1587   return 0;
1588 }
1589
1590 /* Return the length of a chain of nodes chained through TREE_CHAIN.
1591    We expect a null pointer to mark the end of the chain.
1592    This is the Lisp primitive `length'.  */
1593
1594 int
1595 list_length (tree t)
1596 {
1597   tree p = t;
1598 #ifdef ENABLE_TREE_CHECKING
1599   tree q = t;
1600 #endif
1601   int len = 0;
1602
1603   while (p)
1604     {
1605       p = TREE_CHAIN (p);
1606 #ifdef ENABLE_TREE_CHECKING
1607       if (len % 2)
1608         q = TREE_CHAIN (q);
1609       gcc_assert (p != q);
1610 #endif
1611       len++;
1612     }
1613
1614   return len;
1615 }
1616
1617 /* Returns the number of FIELD_DECLs in TYPE.  */
1618
1619 int
1620 fields_length (tree type)
1621 {
1622   tree t = TYPE_FIELDS (type);
1623   int count = 0;
1624
1625   for (; t; t = TREE_CHAIN (t))
1626     if (TREE_CODE (t) == FIELD_DECL)
1627       ++count;
1628
1629   return count;
1630 }
1631
1632 /* Concatenate two chains of nodes (chained through TREE_CHAIN)
1633    by modifying the last node in chain 1 to point to chain 2.
1634    This is the Lisp primitive `nconc'.  */
1635
1636 tree
1637 chainon (tree op1, tree op2)
1638 {
1639   tree t1;
1640
1641   if (!op1)
1642     return op2;
1643   if (!op2)
1644     return op1;
1645
1646   for (t1 = op1; TREE_CHAIN (t1); t1 = TREE_CHAIN (t1))
1647     continue;
1648   TREE_CHAIN (t1) = op2;
1649
1650 #ifdef ENABLE_TREE_CHECKING
1651   {
1652     tree t2;
1653     for (t2 = op2; t2; t2 = TREE_CHAIN (t2))
1654       gcc_assert (t2 != t1);
1655   }
1656 #endif
1657
1658   return op1;
1659 }
1660
1661 /* Return the last node in a chain of nodes (chained through TREE_CHAIN).  */
1662
1663 tree
1664 tree_last (tree chain)
1665 {
1666   tree next;
1667   if (chain)
1668     while ((next = TREE_CHAIN (chain)))
1669       chain = next;
1670   return chain;
1671 }
1672
1673 /* Reverse the order of elements in the chain T,
1674    and return the new head of the chain (old last element).  */
1675
1676 tree
1677 nreverse (tree t)
1678 {
1679   tree prev = 0, decl, next;
1680   for (decl = t; decl; decl = next)
1681     {
1682       next = TREE_CHAIN (decl);
1683       TREE_CHAIN (decl) = prev;
1684       prev = decl;
1685     }
1686   return prev;
1687 }
1688 \f
1689 /* Return a newly created TREE_LIST node whose
1690    purpose and value fields are PARM and VALUE.  */
1691
1692 tree
1693 build_tree_list_stat (tree parm, tree value MEM_STAT_DECL)
1694 {
1695   tree t = make_node_stat (TREE_LIST PASS_MEM_STAT);
1696   TREE_PURPOSE (t) = parm;
1697   TREE_VALUE (t) = value;
1698   return t;
1699 }
1700
1701 /* Return a newly created TREE_LIST node whose
1702    purpose and value fields are PURPOSE and VALUE
1703    and whose TREE_CHAIN is CHAIN.  */
1704
1705 tree
1706 tree_cons_stat (tree purpose, tree value, tree chain MEM_STAT_DECL)
1707 {
1708   tree node;
1709
1710   node = ggc_alloc_zone_pass_stat (sizeof (struct tree_list), &tree_zone);
1711
1712   memset (node, 0, sizeof (struct tree_common));
1713
1714 #ifdef GATHER_STATISTICS
1715   tree_node_counts[(int) x_kind]++;
1716   tree_node_sizes[(int) x_kind] += sizeof (struct tree_list);
1717 #endif
1718
1719   TREE_SET_CODE (node, TREE_LIST);
1720   TREE_CHAIN (node) = chain;
1721   TREE_PURPOSE (node) = purpose;
1722   TREE_VALUE (node) = value;
1723   return node;
1724 }
1725
1726 \f
1727 /* Return the size nominally occupied by an object of type TYPE
1728    when it resides in memory.  The value is measured in units of bytes,
1729    and its data type is that normally used for type sizes
1730    (which is the first type created by make_signed_type or
1731    make_unsigned_type).  */
1732
1733 tree
1734 size_in_bytes (tree type)
1735 {
1736   tree t;
1737
1738   if (type == error_mark_node)
1739     return integer_zero_node;
1740
1741   type = TYPE_MAIN_VARIANT (type);
1742   t = TYPE_SIZE_UNIT (type);
1743
1744   if (t == 0)
1745     {
1746       lang_hooks.types.incomplete_type_error (NULL_TREE, type);
1747       return size_zero_node;
1748     }
1749
1750   if (TREE_CODE (t) == INTEGER_CST)
1751     t = force_fit_type (t, 0, false, false);
1752
1753   return t;
1754 }
1755
1756 /* Return the size of TYPE (in bytes) as a wide integer
1757    or return -1 if the size can vary or is larger than an integer.  */
1758
1759 HOST_WIDE_INT
1760 int_size_in_bytes (tree type)
1761 {
1762   tree t;
1763
1764   if (type == error_mark_node)
1765     return 0;
1766
1767   type = TYPE_MAIN_VARIANT (type);
1768   t = TYPE_SIZE_UNIT (type);
1769   if (t == 0
1770       || TREE_CODE (t) != INTEGER_CST
1771       || TREE_INT_CST_HIGH (t) != 0
1772       /* If the result would appear negative, it's too big to represent.  */
1773       || (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0)
1774     return -1;
1775
1776   return TREE_INT_CST_LOW (t);
1777 }
1778
1779 /* Return the maximum size of TYPE (in bytes) as a wide integer
1780    or return -1 if the size can vary or is larger than an integer.  */
1781
1782 HOST_WIDE_INT
1783 max_int_size_in_bytes (tree type)
1784 {
1785   HOST_WIDE_INT size = -1;
1786   tree size_tree;
1787
1788   /* If this is an array type, check for a possible MAX_SIZE attached.  */
1789
1790   if (TREE_CODE (type) == ARRAY_TYPE)
1791     {
1792       size_tree = TYPE_ARRAY_MAX_SIZE (type);
1793
1794       if (size_tree && host_integerp (size_tree, 1))
1795         size = tree_low_cst (size_tree, 1);
1796     }
1797
1798   /* If we still haven't been able to get a size, see if the language
1799      can compute a maximum size.  */
1800
1801   if (size == -1)
1802     {
1803       size_tree = lang_hooks.types.max_size (type);
1804
1805       if (size_tree && host_integerp (size_tree, 1))
1806         size = tree_low_cst (size_tree, 1);
1807     }
1808
1809   return size;
1810 }
1811 \f
1812 /* Return the bit position of FIELD, in bits from the start of the record.
1813    This is a tree of type bitsizetype.  */
1814
1815 tree
1816 bit_position (tree field)
1817 {
1818   return bit_from_pos (DECL_FIELD_OFFSET (field),
1819                        DECL_FIELD_BIT_OFFSET (field));
1820 }
1821
1822 /* Likewise, but return as an integer.  It must be representable in
1823    that way (since it could be a signed value, we don't have the
1824    option of returning -1 like int_size_in_byte can.  */
1825
1826 HOST_WIDE_INT
1827 int_bit_position (tree field)
1828 {
1829   return tree_low_cst (bit_position (field), 0);
1830 }
1831 \f
1832 /* Return the byte position of FIELD, in bytes from the start of the record.
1833    This is a tree of type sizetype.  */
1834
1835 tree
1836 byte_position (tree field)
1837 {
1838   return byte_from_pos (DECL_FIELD_OFFSET (field),
1839                         DECL_FIELD_BIT_OFFSET (field));
1840 }
1841
1842 /* Likewise, but return as an integer.  It must be representable in
1843    that way (since it could be a signed value, we don't have the
1844    option of returning -1 like int_size_in_byte can.  */
1845
1846 HOST_WIDE_INT
1847 int_byte_position (tree field)
1848 {
1849   return tree_low_cst (byte_position (field), 0);
1850 }
1851 \f
1852 /* Return the strictest alignment, in bits, that T is known to have.  */
1853
1854 unsigned int
1855 expr_align (tree t)
1856 {
1857   unsigned int align0, align1;
1858
1859   switch (TREE_CODE (t))
1860     {
1861     case NOP_EXPR:  case CONVERT_EXPR:  case NON_LVALUE_EXPR:
1862       /* If we have conversions, we know that the alignment of the
1863          object must meet each of the alignments of the types.  */
1864       align0 = expr_align (TREE_OPERAND (t, 0));
1865       align1 = TYPE_ALIGN (TREE_TYPE (t));
1866       return MAX (align0, align1);
1867
1868     case SAVE_EXPR:         case COMPOUND_EXPR:       case MODIFY_EXPR:
1869     case INIT_EXPR:         case TARGET_EXPR:         case WITH_CLEANUP_EXPR:
1870     case CLEANUP_POINT_EXPR:
1871       /* These don't change the alignment of an object.  */
1872       return expr_align (TREE_OPERAND (t, 0));
1873
1874     case COND_EXPR:
1875       /* The best we can do is say that the alignment is the least aligned
1876          of the two arms.  */
1877       align0 = expr_align (TREE_OPERAND (t, 1));
1878       align1 = expr_align (TREE_OPERAND (t, 2));
1879       return MIN (align0, align1);
1880
1881     case LABEL_DECL:     case CONST_DECL:
1882     case VAR_DECL:       case PARM_DECL:   case RESULT_DECL:
1883       if (DECL_ALIGN (t) != 0)
1884         return DECL_ALIGN (t);
1885       break;
1886
1887     case FUNCTION_DECL:
1888       return FUNCTION_BOUNDARY;
1889
1890     default:
1891       break;
1892     }
1893
1894   /* Otherwise take the alignment from that of the type.  */
1895   return TYPE_ALIGN (TREE_TYPE (t));
1896 }
1897 \f
1898 /* Return, as a tree node, the number of elements for TYPE (which is an
1899    ARRAY_TYPE) minus one. This counts only elements of the top array.  */
1900
1901 tree
1902 array_type_nelts (tree type)
1903 {
1904   tree index_type, min, max;
1905
1906   /* If they did it with unspecified bounds, then we should have already
1907      given an error about it before we got here.  */
1908   if (! TYPE_DOMAIN (type))
1909     return error_mark_node;
1910
1911   index_type = TYPE_DOMAIN (type);
1912   min = TYPE_MIN_VALUE (index_type);
1913   max = TYPE_MAX_VALUE (index_type);
1914
1915   return (integer_zerop (min)
1916           ? max
1917           : fold_build2 (MINUS_EXPR, TREE_TYPE (max), max, min));
1918 }
1919 \f
1920 /* If arg is static -- a reference to an object in static storage -- then
1921    return the object.  This is not the same as the C meaning of `static'.
1922    If arg isn't static, return NULL.  */
1923
1924 tree
1925 staticp (tree arg)
1926 {
1927   switch (TREE_CODE (arg))
1928     {
1929     case FUNCTION_DECL:
1930       /* Nested functions are static, even though taking their address will
1931          involve a trampoline as we unnest the nested function and create
1932          the trampoline on the tree level.  */
1933       return arg;
1934
1935     case VAR_DECL:
1936       return ((TREE_STATIC (arg) || DECL_EXTERNAL (arg))
1937               && ! DECL_THREAD_LOCAL_P (arg)
1938               && ! DECL_DLLIMPORT_P (arg)
1939               ? arg : NULL);
1940
1941     case CONST_DECL:
1942       return ((TREE_STATIC (arg) || DECL_EXTERNAL (arg))
1943               ? arg : NULL);
1944
1945     case CONSTRUCTOR:
1946       return TREE_STATIC (arg) ? arg : NULL;
1947
1948     case LABEL_DECL:
1949     case STRING_CST:
1950       return arg;
1951
1952     case COMPONENT_REF:
1953       /* If the thing being referenced is not a field, then it is
1954          something language specific.  */
1955       if (TREE_CODE (TREE_OPERAND (arg, 1)) != FIELD_DECL)
1956         return (*lang_hooks.staticp) (arg);
1957
1958       /* If we are referencing a bitfield, we can't evaluate an
1959          ADDR_EXPR at compile time and so it isn't a constant.  */
1960       if (DECL_BIT_FIELD (TREE_OPERAND (arg, 1)))
1961         return NULL;
1962
1963       return staticp (TREE_OPERAND (arg, 0));
1964
1965     case BIT_FIELD_REF:
1966       return NULL;
1967
1968     case MISALIGNED_INDIRECT_REF:
1969     case ALIGN_INDIRECT_REF:
1970     case INDIRECT_REF:
1971       return TREE_CONSTANT (TREE_OPERAND (arg, 0)) ? arg : NULL;
1972
1973     case ARRAY_REF:
1974     case ARRAY_RANGE_REF:
1975       if (TREE_CODE (TYPE_SIZE (TREE_TYPE (arg))) == INTEGER_CST
1976           && TREE_CODE (TREE_OPERAND (arg, 1)) == INTEGER_CST)
1977         return staticp (TREE_OPERAND (arg, 0));
1978       else
1979         return false;
1980
1981     default:
1982       if ((unsigned int) TREE_CODE (arg)
1983           >= (unsigned int) LAST_AND_UNUSED_TREE_CODE)
1984         return lang_hooks.staticp (arg);
1985       else
1986         return NULL;
1987     }
1988 }
1989 \f
1990 /* Wrap a SAVE_EXPR around EXPR, if appropriate.
1991    Do this to any expression which may be used in more than one place,
1992    but must be evaluated only once.
1993
1994    Normally, expand_expr would reevaluate the expression each time.
1995    Calling save_expr produces something that is evaluated and recorded
1996    the first time expand_expr is called on it.  Subsequent calls to
1997    expand_expr just reuse the recorded value.
1998
1999    The call to expand_expr that generates code that actually computes
2000    the value is the first call *at compile time*.  Subsequent calls
2001    *at compile time* generate code to use the saved value.
2002    This produces correct result provided that *at run time* control
2003    always flows through the insns made by the first expand_expr
2004    before reaching the other places where the save_expr was evaluated.
2005    You, the caller of save_expr, must make sure this is so.
2006
2007    Constants, and certain read-only nodes, are returned with no
2008    SAVE_EXPR because that is safe.  Expressions containing placeholders
2009    are not touched; see tree.def for an explanation of what these
2010    are used for.  */
2011
2012 tree
2013 save_expr (tree expr)
2014 {
2015   tree t = fold (expr);
2016   tree inner;
2017
2018   /* If the tree evaluates to a constant, then we don't want to hide that
2019      fact (i.e. this allows further folding, and direct checks for constants).
2020      However, a read-only object that has side effects cannot be bypassed.
2021      Since it is no problem to reevaluate literals, we just return the
2022      literal node.  */
2023   inner = skip_simple_arithmetic (t);
2024
2025   if (TREE_INVARIANT (inner)
2026       || (TREE_READONLY (inner) && ! TREE_SIDE_EFFECTS (inner))
2027       || TREE_CODE (inner) == SAVE_EXPR
2028       || TREE_CODE (inner) == ERROR_MARK)
2029     return t;
2030
2031   /* If INNER contains a PLACEHOLDER_EXPR, we must evaluate it each time, since
2032      it means that the size or offset of some field of an object depends on
2033      the value within another field.
2034
2035      Note that it must not be the case that T contains both a PLACEHOLDER_EXPR
2036      and some variable since it would then need to be both evaluated once and
2037      evaluated more than once.  Front-ends must assure this case cannot
2038      happen by surrounding any such subexpressions in their own SAVE_EXPR
2039      and forcing evaluation at the proper time.  */
2040   if (contains_placeholder_p (inner))
2041     return t;
2042
2043   t = build1 (SAVE_EXPR, TREE_TYPE (expr), t);
2044
2045   /* This expression might be placed ahead of a jump to ensure that the
2046      value was computed on both sides of the jump.  So make sure it isn't
2047      eliminated as dead.  */
2048   TREE_SIDE_EFFECTS (t) = 1;
2049   TREE_INVARIANT (t) = 1;
2050   return t;
2051 }
2052
2053 /* Look inside EXPR and into any simple arithmetic operations.  Return
2054    the innermost non-arithmetic node.  */
2055
2056 tree
2057 skip_simple_arithmetic (tree expr)
2058 {
2059   tree inner;
2060
2061   /* We don't care about whether this can be used as an lvalue in this
2062      context.  */
2063   while (TREE_CODE (expr) == NON_LVALUE_EXPR)
2064     expr = TREE_OPERAND (expr, 0);
2065
2066   /* If we have simple operations applied to a SAVE_EXPR or to a SAVE_EXPR and
2067      a constant, it will be more efficient to not make another SAVE_EXPR since
2068      it will allow better simplification and GCSE will be able to merge the
2069      computations if they actually occur.  */
2070   inner = expr;
2071   while (1)
2072     {
2073       if (UNARY_CLASS_P (inner))
2074         inner = TREE_OPERAND (inner, 0);
2075       else if (BINARY_CLASS_P (inner))
2076         {
2077           if (TREE_INVARIANT (TREE_OPERAND (inner, 1)))
2078             inner = TREE_OPERAND (inner, 0);
2079           else if (TREE_INVARIANT (TREE_OPERAND (inner, 0)))
2080             inner = TREE_OPERAND (inner, 1);
2081           else
2082             break;
2083         }
2084       else
2085         break;
2086     }
2087
2088   return inner;
2089 }
2090
2091 /* Return which tree structure is used by T.  */
2092
2093 enum tree_node_structure_enum
2094 tree_node_structure (tree t)
2095 {
2096   enum tree_code code = TREE_CODE (t);
2097
2098   switch (TREE_CODE_CLASS (code))
2099     {
2100     case tcc_declaration:
2101       {
2102         switch (code)
2103           {
2104           case FIELD_DECL:
2105             return TS_FIELD_DECL;
2106           case PARM_DECL:
2107             return TS_PARM_DECL;
2108           case VAR_DECL:
2109             return TS_VAR_DECL;
2110           case LABEL_DECL:
2111             return TS_LABEL_DECL;
2112           case RESULT_DECL:
2113             return TS_RESULT_DECL;
2114           case CONST_DECL:
2115             return TS_CONST_DECL;
2116           case TYPE_DECL:
2117             return TS_TYPE_DECL;
2118           case FUNCTION_DECL:
2119             return TS_FUNCTION_DECL;
2120           case SYMBOL_MEMORY_TAG:
2121           case NAME_MEMORY_TAG:
2122           case STRUCT_FIELD_TAG:
2123             return TS_MEMORY_TAG;
2124           default:
2125             return TS_DECL_NON_COMMON;
2126           }
2127       }
2128     case tcc_type:
2129       return TS_TYPE;
2130     case tcc_reference:
2131     case tcc_comparison:
2132     case tcc_unary:
2133     case tcc_binary:
2134     case tcc_expression:
2135     case tcc_statement:
2136       return TS_EXP;
2137     default:  /* tcc_constant and tcc_exceptional */
2138       break;
2139     }
2140   switch (code)
2141     {
2142       /* tcc_constant cases.  */
2143     case INTEGER_CST:           return TS_INT_CST;
2144     case REAL_CST:              return TS_REAL_CST;
2145     case COMPLEX_CST:           return TS_COMPLEX;
2146     case VECTOR_CST:            return TS_VECTOR;
2147     case STRING_CST:            return TS_STRING;
2148       /* tcc_exceptional cases.  */
2149     case ERROR_MARK:            return TS_COMMON;
2150     case IDENTIFIER_NODE:       return TS_IDENTIFIER;
2151     case TREE_LIST:             return TS_LIST;
2152     case TREE_VEC:              return TS_VEC;
2153     case PHI_NODE:              return TS_PHI_NODE;
2154     case SSA_NAME:              return TS_SSA_NAME;
2155     case PLACEHOLDER_EXPR:      return TS_COMMON;
2156     case STATEMENT_LIST:        return TS_STATEMENT_LIST;
2157     case BLOCK:                 return TS_BLOCK;
2158     case CONSTRUCTOR:           return TS_CONSTRUCTOR;
2159     case TREE_BINFO:            return TS_BINFO;
2160     case VALUE_HANDLE:          return TS_VALUE_HANDLE;
2161     case OMP_CLAUSE:            return TS_OMP_CLAUSE;
2162
2163     default:
2164       gcc_unreachable ();
2165     }
2166 }
2167 \f
2168 /* Return 1 if EXP contains a PLACEHOLDER_EXPR; i.e., if it represents a size
2169    or offset that depends on a field within a record.  */
2170
2171 bool
2172 contains_placeholder_p (tree exp)
2173 {
2174   enum tree_code code;
2175
2176   if (!exp)
2177     return 0;
2178
2179   code = TREE_CODE (exp);
2180   if (code == PLACEHOLDER_EXPR)
2181     return 1;
2182
2183   switch (TREE_CODE_CLASS (code))
2184     {
2185     case tcc_reference:
2186       /* Don't look at any PLACEHOLDER_EXPRs that might be in index or bit
2187          position computations since they will be converted into a
2188          WITH_RECORD_EXPR involving the reference, which will assume
2189          here will be valid.  */
2190       return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0));
2191
2192     case tcc_exceptional:
2193       if (code == TREE_LIST)
2194         return (CONTAINS_PLACEHOLDER_P (TREE_VALUE (exp))
2195                 || CONTAINS_PLACEHOLDER_P (TREE_CHAIN (exp)));
2196       break;
2197
2198     case tcc_unary:
2199     case tcc_binary:
2200     case tcc_comparison:
2201     case tcc_expression:
2202       switch (code)
2203         {
2204         case COMPOUND_EXPR:
2205           /* Ignoring the first operand isn't quite right, but works best.  */
2206           return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1));
2207
2208         case COND_EXPR:
2209           return (CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0))
2210                   || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1))
2211                   || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 2)));
2212
2213         case CALL_EXPR:
2214           return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1));
2215
2216         default:
2217           break;
2218         }
2219
2220       switch (TREE_CODE_LENGTH (code))
2221         {
2222         case 1:
2223           return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0));
2224         case 2:
2225           return (CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0))
2226                   || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1)));
2227         default:
2228           return 0;
2229         }
2230
2231     default:
2232       return 0;
2233     }
2234   return 0;
2235 }
2236
2237 /* Return true if any part of the computation of TYPE involves a
2238    PLACEHOLDER_EXPR.  This includes size, bounds, qualifiers
2239    (for QUAL_UNION_TYPE) and field positions.  */
2240
2241 static bool
2242 type_contains_placeholder_1 (tree type)
2243 {
2244   /* If the size contains a placeholder or the parent type (component type in
2245      the case of arrays) type involves a placeholder, this type does.  */
2246   if (CONTAINS_PLACEHOLDER_P (TYPE_SIZE (type))
2247       || CONTAINS_PLACEHOLDER_P (TYPE_SIZE_UNIT (type))
2248       || (TREE_TYPE (type) != 0
2249           && type_contains_placeholder_p (TREE_TYPE (type))))
2250     return true;
2251
2252   /* Now do type-specific checks.  Note that the last part of the check above
2253      greatly limits what we have to do below.  */
2254   switch (TREE_CODE (type))
2255     {
2256     case VOID_TYPE:
2257     case COMPLEX_TYPE:
2258     case ENUMERAL_TYPE:
2259     case BOOLEAN_TYPE:
2260     case POINTER_TYPE:
2261     case OFFSET_TYPE:
2262     case REFERENCE_TYPE:
2263     case METHOD_TYPE:
2264     case FUNCTION_TYPE:
2265     case VECTOR_TYPE:
2266       return false;
2267
2268     case INTEGER_TYPE:
2269     case REAL_TYPE:
2270       /* Here we just check the bounds.  */
2271       return (CONTAINS_PLACEHOLDER_P (TYPE_MIN_VALUE (type))
2272               || CONTAINS_PLACEHOLDER_P (TYPE_MAX_VALUE (type)));
2273
2274     case ARRAY_TYPE:
2275       /* We're already checked the component type (TREE_TYPE), so just check
2276          the index type.  */
2277       return type_contains_placeholder_p (TYPE_DOMAIN (type));
2278
2279     case RECORD_TYPE:
2280     case UNION_TYPE:
2281     case QUAL_UNION_TYPE:
2282       {
2283         tree field;
2284
2285         for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
2286           if (TREE_CODE (field) == FIELD_DECL
2287               && (CONTAINS_PLACEHOLDER_P (DECL_FIELD_OFFSET (field))
2288                   || (TREE_CODE (type) == QUAL_UNION_TYPE
2289                       && CONTAINS_PLACEHOLDER_P (DECL_QUALIFIER (field)))
2290                   || type_contains_placeholder_p (TREE_TYPE (field))))
2291             return true;
2292
2293         return false;
2294       }
2295
2296     default:
2297       gcc_unreachable ();
2298     }
2299 }
2300
2301 bool
2302 type_contains_placeholder_p (tree type)
2303 {
2304   bool result;
2305
2306   /* If the contains_placeholder_bits field has been initialized,
2307      then we know the answer.  */
2308   if (TYPE_CONTAINS_PLACEHOLDER_INTERNAL (type) > 0)
2309     return TYPE_CONTAINS_PLACEHOLDER_INTERNAL (type) - 1;
2310
2311   /* Indicate that we've seen this type node, and the answer is false.
2312      This is what we want to return if we run into recursion via fields.  */
2313   TYPE_CONTAINS_PLACEHOLDER_INTERNAL (type) = 1;
2314
2315   /* Compute the real value.  */
2316   result = type_contains_placeholder_1 (type);
2317
2318   /* Store the real value.  */
2319   TYPE_CONTAINS_PLACEHOLDER_INTERNAL (type) = result + 1;
2320
2321   return result;
2322 }
2323 \f
2324 /* Given a tree EXP, a FIELD_DECL F, and a replacement value R,
2325    return a tree with all occurrences of references to F in a
2326    PLACEHOLDER_EXPR replaced by R.   Note that we assume here that EXP
2327    contains only arithmetic expressions or a CALL_EXPR with a
2328    PLACEHOLDER_EXPR occurring only in its arglist.  */
2329
2330 tree
2331 substitute_in_expr (tree exp, tree f, tree r)
2332 {
2333   enum tree_code code = TREE_CODE (exp);
2334   tree op0, op1, op2, op3;
2335   tree new;
2336   tree inner;
2337
2338   /* We handle TREE_LIST and COMPONENT_REF separately.  */
2339   if (code == TREE_LIST)
2340     {
2341       op0 = SUBSTITUTE_IN_EXPR (TREE_CHAIN (exp), f, r);
2342       op1 = SUBSTITUTE_IN_EXPR (TREE_VALUE (exp), f, r);
2343       if (op0 == TREE_CHAIN (exp) && op1 == TREE_VALUE (exp))
2344         return exp;
2345
2346       return tree_cons (TREE_PURPOSE (exp), op1, op0);
2347     }
2348   else if (code == COMPONENT_REF)
2349    {
2350      /* If this expression is getting a value from a PLACEHOLDER_EXPR
2351         and it is the right field, replace it with R.  */
2352      for (inner = TREE_OPERAND (exp, 0);
2353           REFERENCE_CLASS_P (inner);
2354           inner = TREE_OPERAND (inner, 0))
2355        ;
2356      if (TREE_CODE (inner) == PLACEHOLDER_EXPR
2357          && TREE_OPERAND (exp, 1) == f)
2358        return r;
2359
2360      /* If this expression hasn't been completed let, leave it alone.  */
2361      if (TREE_CODE (inner) == PLACEHOLDER_EXPR && TREE_TYPE (inner) == 0)
2362        return exp;
2363
2364      op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2365      if (op0 == TREE_OPERAND (exp, 0))
2366        return exp;
2367
2368      new = fold_build3 (COMPONENT_REF, TREE_TYPE (exp),
2369                         op0, TREE_OPERAND (exp, 1), NULL_TREE);
2370    }
2371   else
2372     switch (TREE_CODE_CLASS (code))
2373       {
2374       case tcc_constant:
2375       case tcc_declaration:
2376         return exp;
2377
2378       case tcc_exceptional:
2379       case tcc_unary:
2380       case tcc_binary:
2381       case tcc_comparison:
2382       case tcc_expression:
2383       case tcc_reference:
2384         switch (TREE_CODE_LENGTH (code))
2385           {
2386           case 0:
2387             return exp;
2388
2389           case 1:
2390             op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2391             if (op0 == TREE_OPERAND (exp, 0))
2392               return exp;
2393
2394             new = fold_build1 (code, TREE_TYPE (exp), op0);
2395             break;
2396
2397           case 2:
2398             op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2399             op1 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 1), f, r);
2400
2401             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1))
2402               return exp;
2403
2404             new = fold_build2 (code, TREE_TYPE (exp), op0, op1);
2405             break;
2406
2407           case 3:
2408             op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2409             op1 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 1), f, r);
2410             op2 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 2), f, r);
2411
2412             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1)
2413                 && op2 == TREE_OPERAND (exp, 2))
2414               return exp;
2415
2416             new = fold_build3 (code, TREE_TYPE (exp), op0, op1, op2);
2417             break;
2418
2419           case 4:
2420             op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2421             op1 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 1), f, r);
2422             op2 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 2), f, r);
2423             op3 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 3), f, r);
2424
2425             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1)
2426                 && op2 == TREE_OPERAND (exp, 2)
2427                 && op3 == TREE_OPERAND (exp, 3))
2428               return exp;
2429
2430             new = fold (build4 (code, TREE_TYPE (exp), op0, op1, op2, op3));
2431             break;
2432
2433           default:
2434             gcc_unreachable ();
2435           }
2436         break;
2437
2438       default:
2439         gcc_unreachable ();
2440       }
2441
2442   TREE_READONLY (new) = TREE_READONLY (exp);
2443   return new;
2444 }
2445
2446 /* Similar, but look for a PLACEHOLDER_EXPR in EXP and find a replacement
2447    for it within OBJ, a tree that is an object or a chain of references.  */
2448
2449 tree
2450 substitute_placeholder_in_expr (tree exp, tree obj)
2451 {
2452   enum tree_code code = TREE_CODE (exp);
2453   tree op0, op1, op2, op3;
2454
2455   /* If this is a PLACEHOLDER_EXPR, see if we find a corresponding type
2456      in the chain of OBJ.  */
2457   if (code == PLACEHOLDER_EXPR)
2458     {
2459       tree need_type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
2460       tree elt;
2461
2462       for (elt = obj; elt != 0;
2463            elt = ((TREE_CODE (elt) == COMPOUND_EXPR
2464                    || TREE_CODE (elt) == COND_EXPR)
2465                   ? TREE_OPERAND (elt, 1)
2466                   : (REFERENCE_CLASS_P (elt)
2467                      || UNARY_CLASS_P (elt)
2468                      || BINARY_CLASS_P (elt)
2469                      || EXPRESSION_CLASS_P (elt))
2470                   ? TREE_OPERAND (elt, 0) : 0))
2471         if (TYPE_MAIN_VARIANT (TREE_TYPE (elt)) == need_type)
2472           return elt;
2473
2474       for (elt = obj; elt != 0;
2475            elt = ((TREE_CODE (elt) == COMPOUND_EXPR
2476                    || TREE_CODE (elt) == COND_EXPR)
2477                   ? TREE_OPERAND (elt, 1)
2478                   : (REFERENCE_CLASS_P (elt)
2479                      || UNARY_CLASS_P (elt)
2480                      || BINARY_CLASS_P (elt)
2481                      || EXPRESSION_CLASS_P (elt))
2482                   ? TREE_OPERAND (elt, 0) : 0))
2483         if (POINTER_TYPE_P (TREE_TYPE (elt))
2484             && (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (elt)))
2485                 == need_type))
2486           return fold_build1 (INDIRECT_REF, need_type, elt);
2487
2488       /* If we didn't find it, return the original PLACEHOLDER_EXPR.  If it
2489          survives until RTL generation, there will be an error.  */
2490       return exp;
2491     }
2492
2493   /* TREE_LIST is special because we need to look at TREE_VALUE
2494      and TREE_CHAIN, not TREE_OPERANDS.  */
2495   else if (code == TREE_LIST)
2496     {
2497       op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_CHAIN (exp), obj);
2498       op1 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_VALUE (exp), obj);
2499       if (op0 == TREE_CHAIN (exp) && op1 == TREE_VALUE (exp))
2500         return exp;
2501
2502       return tree_cons (TREE_PURPOSE (exp), op1, op0);
2503     }
2504   else
2505     switch (TREE_CODE_CLASS (code))
2506       {
2507       case tcc_constant:
2508       case tcc_declaration:
2509         return exp;
2510
2511       case tcc_exceptional:
2512       case tcc_unary:
2513       case tcc_binary:
2514       case tcc_comparison:
2515       case tcc_expression:
2516       case tcc_reference:
2517       case tcc_statement:
2518         switch (TREE_CODE_LENGTH (code))
2519           {
2520           case 0:
2521             return exp;
2522
2523           case 1:
2524             op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 0), obj);
2525             if (op0 == TREE_OPERAND (exp, 0))
2526               return exp;
2527             else
2528               return fold_build1 (code, TREE_TYPE (exp), op0);
2529
2530           case 2:
2531             op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 0), obj);
2532             op1 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 1), obj);
2533
2534             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1))
2535               return exp;
2536             else
2537               return fold_build2 (code, TREE_TYPE (exp), op0, op1);
2538
2539           case 3:
2540             op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 0), obj);
2541             op1 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 1), obj);
2542             op2 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 2), obj);
2543
2544             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1)
2545                 && op2 == TREE_OPERAND (exp, 2))
2546               return exp;
2547             else
2548               return fold_build3 (code, TREE_TYPE (exp), op0, op1, op2);
2549
2550           case 4:
2551             op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 0), obj);
2552             op1 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 1), obj);
2553             op2 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 2), obj);
2554             op3 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 3), obj);
2555
2556             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1)
2557                 && op2 == TREE_OPERAND (exp, 2)
2558                 && op3 == TREE_OPERAND (exp, 3))
2559               return exp;
2560             else
2561               return fold (build4 (code, TREE_TYPE (exp), op0, op1, op2, op3));
2562
2563           default:
2564             gcc_unreachable ();
2565           }
2566         break;
2567
2568       default:
2569         gcc_unreachable ();
2570       }
2571 }
2572 \f
2573 /* Stabilize a reference so that we can use it any number of times
2574    without causing its operands to be evaluated more than once.
2575    Returns the stabilized reference.  This works by means of save_expr,
2576    so see the caveats in the comments about save_expr.
2577
2578    Also allows conversion expressions whose operands are references.
2579    Any other kind of expression is returned unchanged.  */
2580
2581 tree
2582 stabilize_reference (tree ref)
2583 {
2584   tree result;
2585   enum tree_code code = TREE_CODE (ref);
2586
2587   switch (code)
2588     {
2589     case VAR_DECL:
2590     case PARM_DECL:
2591     case RESULT_DECL:
2592       /* No action is needed in this case.  */
2593       return ref;
2594
2595     case NOP_EXPR:
2596     case CONVERT_EXPR:
2597     case FLOAT_EXPR:
2598     case FIX_TRUNC_EXPR:
2599     case FIX_FLOOR_EXPR:
2600     case FIX_ROUND_EXPR:
2601     case FIX_CEIL_EXPR:
2602       result = build_nt (code, stabilize_reference (TREE_OPERAND (ref, 0)));
2603       break;
2604
2605     case INDIRECT_REF:
2606       result = build_nt (INDIRECT_REF,
2607                          stabilize_reference_1 (TREE_OPERAND (ref, 0)));
2608       break;
2609
2610     case COMPONENT_REF:
2611       result = build_nt (COMPONENT_REF,
2612                          stabilize_reference (TREE_OPERAND (ref, 0)),
2613                          TREE_OPERAND (ref, 1), NULL_TREE);
2614       break;
2615
2616     case BIT_FIELD_REF:
2617       result = build_nt (BIT_FIELD_REF,
2618                          stabilize_reference (TREE_OPERAND (ref, 0)),
2619                          stabilize_reference_1 (TREE_OPERAND (ref, 1)),
2620                          stabilize_reference_1 (TREE_OPERAND (ref, 2)));
2621       break;
2622
2623     case ARRAY_REF:
2624       result = build_nt (ARRAY_REF,
2625                          stabilize_reference (TREE_OPERAND (ref, 0)),
2626                          stabilize_reference_1 (TREE_OPERAND (ref, 1)),
2627                          TREE_OPERAND (ref, 2), TREE_OPERAND (ref, 3));
2628       break;
2629
2630     case ARRAY_RANGE_REF:
2631       result = build_nt (ARRAY_RANGE_REF,
2632                          stabilize_reference (TREE_OPERAND (ref, 0)),
2633                          stabilize_reference_1 (TREE_OPERAND (ref, 1)),
2634                          TREE_OPERAND (ref, 2), TREE_OPERAND (ref, 3));
2635       break;
2636
2637     case COMPOUND_EXPR:
2638       /* We cannot wrap the first expression in a SAVE_EXPR, as then
2639          it wouldn't be ignored.  This matters when dealing with
2640          volatiles.  */
2641       return stabilize_reference_1 (ref);
2642
2643       /* If arg isn't a kind of lvalue we recognize, make no change.
2644          Caller should recognize the error for an invalid lvalue.  */
2645     default:
2646       return ref;
2647
2648     case ERROR_MARK:
2649       return error_mark_node;
2650     }
2651
2652   TREE_TYPE (result) = TREE_TYPE (ref);
2653   TREE_READONLY (result) = TREE_READONLY (ref);
2654   TREE_SIDE_EFFECTS (result) = TREE_SIDE_EFFECTS (ref);
2655   TREE_THIS_VOLATILE (result) = TREE_THIS_VOLATILE (ref);
2656
2657   return result;
2658 }
2659
2660 /* Subroutine of stabilize_reference; this is called for subtrees of
2661    references.  Any expression with side-effects must be put in a SAVE_EXPR
2662    to ensure that it is only evaluated once.
2663
2664    We don't put SAVE_EXPR nodes around everything, because assigning very
2665    simple expressions to temporaries causes us to miss good opportunities
2666    for optimizations.  Among other things, the opportunity to fold in the
2667    addition of a constant into an addressing mode often gets lost, e.g.
2668    "y[i+1] += x;".  In general, we take the approach that we should not make
2669    an assignment unless we are forced into it - i.e., that any non-side effect
2670    operator should be allowed, and that cse should take care of coalescing
2671    multiple utterances of the same expression should that prove fruitful.  */
2672
2673 tree
2674 stabilize_reference_1 (tree e)
2675 {
2676   tree result;
2677   enum tree_code code = TREE_CODE (e);
2678
2679   /* We cannot ignore const expressions because it might be a reference
2680      to a const array but whose index contains side-effects.  But we can
2681      ignore things that are actual constant or that already have been
2682      handled by this function.  */
2683
2684   if (TREE_INVARIANT (e))
2685     return e;
2686
2687   switch (TREE_CODE_CLASS (code))
2688     {
2689     case tcc_exceptional:
2690     case tcc_type:
2691     case tcc_declaration:
2692     case tcc_comparison:
2693     case tcc_statement:
2694     case tcc_expression:
2695     case tcc_reference:
2696       /* If the expression has side-effects, then encase it in a SAVE_EXPR
2697          so that it will only be evaluated once.  */
2698       /* The reference (r) and comparison (<) classes could be handled as
2699          below, but it is generally faster to only evaluate them once.  */
2700       if (TREE_SIDE_EFFECTS (e))
2701         return save_expr (e);
2702       return e;
2703
2704     case tcc_constant:
2705       /* Constants need no processing.  In fact, we should never reach
2706          here.  */
2707       return e;
2708
2709     case tcc_binary:
2710       /* Division is slow and tends to be compiled with jumps,
2711          especially the division by powers of 2 that is often
2712          found inside of an array reference.  So do it just once.  */
2713       if (code == TRUNC_DIV_EXPR || code == TRUNC_MOD_EXPR
2714           || code == FLOOR_DIV_EXPR || code == FLOOR_MOD_EXPR
2715           || code == CEIL_DIV_EXPR || code == CEIL_MOD_EXPR
2716           || code == ROUND_DIV_EXPR || code == ROUND_MOD_EXPR)
2717         return save_expr (e);
2718       /* Recursively stabilize each operand.  */
2719       result = build_nt (code, stabilize_reference_1 (TREE_OPERAND (e, 0)),
2720                          stabilize_reference_1 (TREE_OPERAND (e, 1)));
2721       break;
2722
2723     case tcc_unary:
2724       /* Recursively stabilize each operand.  */
2725       result = build_nt (code, stabilize_reference_1 (TREE_OPERAND (e, 0)));
2726       break;
2727
2728     default:
2729       gcc_unreachable ();
2730     }
2731
2732   TREE_TYPE (result) = TREE_TYPE (e);
2733   TREE_READONLY (result) = TREE_READONLY (e);
2734   TREE_SIDE_EFFECTS (result) = TREE_SIDE_EFFECTS (e);
2735   TREE_THIS_VOLATILE (result) = TREE_THIS_VOLATILE (e);
2736   TREE_INVARIANT (result) = 1;
2737
2738   return result;
2739 }
2740 \f
2741 /* Low-level constructors for expressions.  */
2742
2743 /* A helper function for build1 and constant folders.  Set TREE_CONSTANT,
2744    TREE_INVARIANT, and TREE_SIDE_EFFECTS for an ADDR_EXPR.  */
2745
2746 void
2747 recompute_tree_invariant_for_addr_expr (tree t)
2748 {
2749   tree node;
2750   bool tc = true, ti = true, se = false;
2751
2752   /* We started out assuming this address is both invariant and constant, but
2753      does not have side effects.  Now go down any handled components and see if
2754      any of them involve offsets that are either non-constant or non-invariant.
2755      Also check for side-effects.
2756
2757      ??? Note that this code makes no attempt to deal with the case where
2758      taking the address of something causes a copy due to misalignment.  */
2759
2760 #define UPDATE_TITCSE(NODE)  \
2761 do { tree _node = (NODE); \
2762      if (_node && !TREE_INVARIANT (_node)) ti = false; \
2763      if (_node && !TREE_CONSTANT (_node)) tc = false; \
2764      if (_node && TREE_SIDE_EFFECTS (_node)) se = true; } while (0)
2765
2766   for (node = TREE_OPERAND (t, 0); handled_component_p (node);
2767        node = TREE_OPERAND (node, 0))
2768     {
2769       /* If the first operand doesn't have an ARRAY_TYPE, this is a bogus
2770          array reference (probably made temporarily by the G++ front end),
2771          so ignore all the operands.  */
2772       if ((TREE_CODE (node) == ARRAY_REF
2773            || TREE_CODE (node) == ARRAY_RANGE_REF)
2774           && TREE_CODE (TREE_TYPE (TREE_OPERAND (node, 0))) == ARRAY_TYPE)
2775         {
2776           UPDATE_TITCSE (TREE_OPERAND (node, 1));
2777           if (TREE_OPERAND (node, 2))
2778             UPDATE_TITCSE (TREE_OPERAND (node, 2));
2779           if (TREE_OPERAND (node, 3))
2780             UPDATE_TITCSE (TREE_OPERAND (node, 3));
2781         }
2782       /* Likewise, just because this is a COMPONENT_REF doesn't mean we have a
2783          FIELD_DECL, apparently.  The G++ front end can put something else
2784          there, at least temporarily.  */
2785       else if (TREE_CODE (node) == COMPONENT_REF
2786                && TREE_CODE (TREE_OPERAND (node, 1)) == FIELD_DECL)
2787         {
2788           if (TREE_OPERAND (node, 2))
2789             UPDATE_TITCSE (TREE_OPERAND (node, 2));
2790         }
2791       else if (TREE_CODE (node) == BIT_FIELD_REF)
2792         UPDATE_TITCSE (TREE_OPERAND (node, 2));
2793     }
2794
2795   node = lang_hooks.expr_to_decl (node, &tc, &ti, &se);
2796
2797   /* Now see what's inside.  If it's an INDIRECT_REF, copy our properties from
2798      the address, since &(*a)->b is a form of addition.  If it's a decl, it's
2799      invariant and constant if the decl is static.  It's also invariant if it's
2800      a decl in the current function.  Taking the address of a volatile variable
2801      is not volatile.  If it's a constant, the address is both invariant and
2802      constant.  Otherwise it's neither.  */
2803   if (TREE_CODE (node) == INDIRECT_REF)
2804     UPDATE_TITCSE (TREE_OPERAND (node, 0));
2805   else if (DECL_P (node))
2806     {
2807       if (staticp (node))
2808         ;
2809       else if (decl_function_context (node) == current_function_decl
2810                /* Addresses of thread-local variables are invariant.  */
2811                || (TREE_CODE (node) == VAR_DECL
2812                    && DECL_THREAD_LOCAL_P (node)))
2813         tc = false;
2814       else
2815         ti = tc = false;
2816     }
2817   else if (CONSTANT_CLASS_P (node))
2818     ;
2819   else
2820     {
2821       ti = tc = false;
2822       se |= TREE_SIDE_EFFECTS (node);
2823     }
2824
2825   TREE_CONSTANT (t) = tc;
2826   TREE_INVARIANT (t) = ti;
2827   TREE_SIDE_EFFECTS (t) = se;
2828 #undef UPDATE_TITCSE
2829 }
2830
2831 /* Build an expression of code CODE, data type TYPE, and operands as
2832    specified.  Expressions and reference nodes can be created this way.
2833    Constants, decls, types and misc nodes cannot be.
2834
2835    We define 5 non-variadic functions, from 0 to 4 arguments.  This is
2836    enough for all extant tree codes.  */
2837
2838 tree
2839 build0_stat (enum tree_code code, tree tt MEM_STAT_DECL)
2840 {
2841   tree t;
2842
2843   gcc_assert (TREE_CODE_LENGTH (code) == 0);
2844
2845   t = make_node_stat (code PASS_MEM_STAT);
2846   TREE_TYPE (t) = tt;
2847
2848   return t;
2849 }
2850
2851 tree
2852 build1_stat (enum tree_code code, tree type, tree node MEM_STAT_DECL)
2853 {
2854   int length = sizeof (struct tree_exp);
2855 #ifdef GATHER_STATISTICS
2856   tree_node_kind kind;
2857 #endif
2858   tree t;
2859
2860 #ifdef GATHER_STATISTICS
2861   switch (TREE_CODE_CLASS (code))
2862     {
2863     case tcc_statement:  /* an expression with side effects */
2864       kind = s_kind;
2865       break;
2866     case tcc_reference:  /* a reference */
2867       kind = r_kind;
2868       break;
2869     default:
2870       kind = e_kind;
2871       break;
2872     }
2873
2874   tree_node_counts[(int) kind]++;
2875   tree_node_sizes[(int) kind] += length;
2876 #endif
2877
2878   gcc_assert (TREE_CODE_LENGTH (code) == 1);
2879
2880   t = ggc_alloc_zone_pass_stat (length, &tree_zone);
2881
2882   memset (t, 0, sizeof (struct tree_common));
2883
2884   TREE_SET_CODE (t, code);
2885
2886   TREE_TYPE (t) = type;
2887 #ifdef USE_MAPPED_LOCATION
2888   SET_EXPR_LOCATION (t, UNKNOWN_LOCATION);
2889 #else
2890   SET_EXPR_LOCUS (t, NULL);
2891 #endif
2892   TREE_COMPLEXITY (t) = 0;
2893   TREE_OPERAND (t, 0) = node;
2894   TREE_BLOCK (t) = NULL_TREE;
2895   if (node && !TYPE_P (node))
2896     {
2897       TREE_SIDE_EFFECTS (t) = TREE_SIDE_EFFECTS (node);
2898       TREE_READONLY (t) = TREE_READONLY (node);
2899     }
2900
2901   if (TREE_CODE_CLASS (code) == tcc_statement)
2902     TREE_SIDE_EFFECTS (t) = 1;
2903   else switch (code)
2904     {
2905     case VA_ARG_EXPR:
2906       /* All of these have side-effects, no matter what their
2907          operands are.  */
2908       TREE_SIDE_EFFECTS (t) = 1;
2909       TREE_READONLY (t) = 0;
2910       break;
2911
2912     case MISALIGNED_INDIRECT_REF:
2913     case ALIGN_INDIRECT_REF:
2914     case INDIRECT_REF:
2915       /* Whether a dereference is readonly has nothing to do with whether
2916          its operand is readonly.  */
2917       TREE_READONLY (t) = 0;
2918       break;
2919
2920     case ADDR_EXPR:
2921       if (node)
2922         recompute_tree_invariant_for_addr_expr (t);
2923       break;
2924
2925     default:
2926       if ((TREE_CODE_CLASS (code) == tcc_unary || code == VIEW_CONVERT_EXPR)
2927           && node && !TYPE_P (node)
2928           && TREE_CONSTANT (node))
2929         TREE_CONSTANT (t) = 1;
2930       if ((TREE_CODE_CLASS (code) == tcc_unary || code == VIEW_CONVERT_EXPR)
2931           && node && TREE_INVARIANT (node))
2932         TREE_INVARIANT (t) = 1;
2933       if (TREE_CODE_CLASS (code) == tcc_reference
2934           && node && TREE_THIS_VOLATILE (node))
2935         TREE_THIS_VOLATILE (t) = 1;
2936       break;
2937     }
2938
2939   return t;
2940 }
2941
2942 #define PROCESS_ARG(N)                  \
2943   do {                                  \
2944     TREE_OPERAND (t, N) = arg##N;       \
2945     if (arg##N &&!TYPE_P (arg##N))      \
2946       {                                 \
2947         if (TREE_SIDE_EFFECTS (arg##N)) \
2948           side_effects = 1;             \
2949         if (!TREE_READONLY (arg##N))    \
2950           read_only = 0;                \
2951         if (!TREE_CONSTANT (arg##N))    \
2952           constant = 0;                 \
2953         if (!TREE_INVARIANT (arg##N))   \
2954           invariant = 0;                \
2955       }                                 \
2956   } while (0)
2957
2958 tree
2959 build2_stat (enum tree_code code, tree tt, tree arg0, tree arg1 MEM_STAT_DECL)
2960 {
2961   bool constant, read_only, side_effects, invariant;
2962   tree t;
2963
2964   gcc_assert (TREE_CODE_LENGTH (code) == 2);
2965
2966   t = make_node_stat (code PASS_MEM_STAT);
2967   TREE_TYPE (t) = tt;
2968
2969   /* Below, we automatically set TREE_SIDE_EFFECTS and TREE_READONLY for the
2970      result based on those same flags for the arguments.  But if the
2971      arguments aren't really even `tree' expressions, we shouldn't be trying
2972      to do this.  */
2973
2974   /* Expressions without side effects may be constant if their
2975      arguments are as well.  */
2976   constant = (TREE_CODE_CLASS (code) == tcc_comparison
2977               || TREE_CODE_CLASS (code) == tcc_binary);
2978   read_only = 1;
2979   side_effects = TREE_SIDE_EFFECTS (t);
2980   invariant = constant;
2981
2982   PROCESS_ARG(0);
2983   PROCESS_ARG(1);
2984
2985   TREE_READONLY (t) = read_only;
2986   TREE_CONSTANT (t) = constant;
2987   TREE_INVARIANT (t) = invariant;
2988   TREE_SIDE_EFFECTS (t) = side_effects;
2989   TREE_THIS_VOLATILE (t)
2990     = (TREE_CODE_CLASS (code) == tcc_reference
2991        && arg0 && TREE_THIS_VOLATILE (arg0));
2992
2993   return t;
2994 }
2995
2996 tree
2997 build3_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
2998              tree arg2 MEM_STAT_DECL)
2999 {
3000   bool constant, read_only, side_effects, invariant;
3001   tree t;
3002
3003   gcc_assert (TREE_CODE_LENGTH (code) == 3);
3004
3005   t = make_node_stat (code PASS_MEM_STAT);
3006   TREE_TYPE (t) = tt;
3007
3008   side_effects = TREE_SIDE_EFFECTS (t);
3009
3010   PROCESS_ARG(0);
3011   PROCESS_ARG(1);
3012   PROCESS_ARG(2);
3013
3014   if (code == CALL_EXPR && !side_effects)
3015     {
3016       tree node;
3017       int i;
3018
3019       /* Calls have side-effects, except those to const or
3020          pure functions.  */
3021       i = call_expr_flags (t);
3022       if (!(i & (ECF_CONST | ECF_PURE)))
3023         side_effects = 1;
3024
3025       /* And even those have side-effects if their arguments do.  */
3026       else for (node = arg1; node; node = TREE_CHAIN (node))
3027         if (TREE_SIDE_EFFECTS (TREE_VALUE (node)))
3028           {
3029             side_effects = 1;
3030             break;
3031           }
3032     }
3033
3034   TREE_SIDE_EFFECTS (t) = side_effects;
3035   TREE_THIS_VOLATILE (t)
3036     = (TREE_CODE_CLASS (code) == tcc_reference
3037        && arg0 && TREE_THIS_VOLATILE (arg0));
3038
3039   return t;
3040 }
3041
3042 tree
3043 build4_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3044              tree arg2, tree arg3 MEM_STAT_DECL)
3045 {
3046   bool constant, read_only, side_effects, invariant;
3047   tree t;
3048
3049   gcc_assert (TREE_CODE_LENGTH (code) == 4);
3050
3051   t = make_node_stat (code PASS_MEM_STAT);
3052   TREE_TYPE (t) = tt;
3053
3054   side_effects = TREE_SIDE_EFFECTS (t);
3055
3056   PROCESS_ARG(0);
3057   PROCESS_ARG(1);
3058   PROCESS_ARG(2);
3059   PROCESS_ARG(3);
3060
3061   TREE_SIDE_EFFECTS (t) = side_effects;
3062   TREE_THIS_VOLATILE (t)
3063     = (TREE_CODE_CLASS (code) == tcc_reference
3064        && arg0 && TREE_THIS_VOLATILE (arg0));
3065
3066   return t;
3067 }
3068
3069 tree
3070 build5_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3071              tree arg2, tree arg3, tree arg4 MEM_STAT_DECL)
3072 {
3073   bool constant, read_only, side_effects, invariant;
3074   tree t;
3075
3076   gcc_assert (TREE_CODE_LENGTH (code) == 5);
3077
3078   t = make_node_stat (code PASS_MEM_STAT);
3079   TREE_TYPE (t) = tt;
3080
3081   side_effects = TREE_SIDE_EFFECTS (t);
3082
3083   PROCESS_ARG(0);
3084   PROCESS_ARG(1);
3085   PROCESS_ARG(2);
3086   PROCESS_ARG(3);
3087   PROCESS_ARG(4);
3088
3089   TREE_SIDE_EFFECTS (t) = side_effects;
3090   TREE_THIS_VOLATILE (t)
3091     = (TREE_CODE_CLASS (code) == tcc_reference
3092        && arg0 && TREE_THIS_VOLATILE (arg0));
3093
3094   return t;
3095 }
3096
3097 tree
3098 build7_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3099              tree arg2, tree arg3, tree arg4, tree arg5,
3100              tree arg6 MEM_STAT_DECL)
3101 {
3102   bool constant, read_only, side_effects, invariant;
3103   tree t;
3104
3105   gcc_assert (code == TARGET_MEM_REF);
3106
3107   t = make_node_stat (code PASS_MEM_STAT);
3108   TREE_TYPE (t) = tt;
3109
3110   side_effects = TREE_SIDE_EFFECTS (t);
3111
3112   PROCESS_ARG(0);
3113   PROCESS_ARG(1);
3114   PROCESS_ARG(2);
3115   PROCESS_ARG(3);
3116   PROCESS_ARG(4);
3117   PROCESS_ARG(5);
3118   PROCESS_ARG(6);
3119
3120   TREE_SIDE_EFFECTS (t) = side_effects;
3121   TREE_THIS_VOLATILE (t) = 0;
3122
3123   return t;
3124 }
3125
3126 /* Similar except don't specify the TREE_TYPE
3127    and leave the TREE_SIDE_EFFECTS as 0.
3128    It is permissible for arguments to be null,
3129    or even garbage if their values do not matter.  */
3130
3131 tree
3132 build_nt (enum tree_code code, ...)
3133 {
3134   tree t;
3135   int length;
3136   int i;
3137   va_list p;
3138
3139   va_start (p, code);
3140
3141   t = make_node (code);
3142   length = TREE_CODE_LENGTH (code);
3143
3144   for (i = 0; i < length; i++)
3145     TREE_OPERAND (t, i) = va_arg (p, tree);
3146
3147   va_end (p);
3148   return t;
3149 }
3150 \f
3151 /* Create a DECL_... node of code CODE, name NAME and data type TYPE.
3152    We do NOT enter this node in any sort of symbol table.
3153
3154    layout_decl is used to set up the decl's storage layout.
3155    Other slots are initialized to 0 or null pointers.  */
3156
3157 tree
3158 build_decl_stat (enum tree_code code, tree name, tree type MEM_STAT_DECL)
3159 {
3160   tree t;
3161
3162   t = make_node_stat (code PASS_MEM_STAT);
3163
3164 /*  if (type == error_mark_node)
3165     type = integer_type_node; */
3166 /* That is not done, deliberately, so that having error_mark_node
3167    as the type can suppress useless errors in the use of this variable.  */
3168
3169   DECL_NAME (t) = name;
3170   TREE_TYPE (t) = type;
3171
3172   if (code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL)
3173     layout_decl (t, 0);
3174   else if (code == FUNCTION_DECL)
3175     DECL_MODE (t) = FUNCTION_MODE;
3176
3177   return t;
3178 }
3179
3180 /* Builds and returns function declaration with NAME and TYPE.  */
3181
3182 tree
3183 build_fn_decl (const char *name, tree type)
3184 {
3185   tree id = get_identifier (name);
3186   tree decl = build_decl (FUNCTION_DECL, id, type);
3187
3188   DECL_EXTERNAL (decl) = 1;
3189   TREE_PUBLIC (decl) = 1;
3190   DECL_ARTIFICIAL (decl) = 1;
3191   TREE_NOTHROW (decl) = 1;
3192
3193   return decl;
3194 }
3195
3196 \f
3197 /* BLOCK nodes are used to represent the structure of binding contours
3198    and declarations, once those contours have been exited and their contents
3199    compiled.  This information is used for outputting debugging info.  */
3200
3201 tree
3202 build_block (tree vars, tree subblocks, tree supercontext, tree chain)
3203 {
3204   tree block = make_node (BLOCK);
3205
3206   BLOCK_VARS (block) = vars;
3207   BLOCK_SUBBLOCKS (block) = subblocks;
3208   BLOCK_SUPERCONTEXT (block) = supercontext;
3209   BLOCK_CHAIN (block) = chain;
3210   return block;
3211 }
3212
3213 #if 1 /* ! defined(USE_MAPPED_LOCATION) */
3214 /* ??? gengtype doesn't handle conditionals */
3215 static GTY(()) source_locus last_annotated_node;
3216 #endif
3217
3218 #ifdef USE_MAPPED_LOCATION
3219
3220 expanded_location
3221 expand_location (source_location loc)
3222 {
3223   expanded_location xloc;
3224   if (loc == 0) { xloc.file = NULL; xloc.line = 0;  xloc.column = 0; }
3225   else
3226     {
3227       const struct line_map *map = linemap_lookup (&line_table, loc);
3228       xloc.file = map->to_file;
3229       xloc.line = SOURCE_LINE (map, loc);
3230       xloc.column = SOURCE_COLUMN (map, loc);
3231     };
3232   return xloc;
3233 }
3234
3235 #else
3236
3237 /* Record the exact location where an expression or an identifier were
3238    encountered.  */
3239
3240 void
3241 annotate_with_file_line (tree node, const char *file, int line)
3242 {
3243   /* Roughly one percent of the calls to this function are to annotate
3244      a node with the same information already attached to that node!
3245      Just return instead of wasting memory.  */
3246   if (EXPR_LOCUS (node)
3247       && EXPR_LINENO (node) == line
3248       && (EXPR_FILENAME (node) == file
3249           || !strcmp (EXPR_FILENAME (node), file)))
3250     {
3251       last_annotated_node = EXPR_LOCUS (node);
3252       return;
3253     }
3254
3255   /* In heavily macroized code (such as GCC itself) this single
3256      entry cache can reduce the number of allocations by more
3257      than half.  */
3258   if (last_annotated_node
3259       && last_annotated_node->line == line
3260       && (last_annotated_node->file == file
3261           || !strcmp (last_annotated_node->file, file)))
3262     {
3263       SET_EXPR_LOCUS (node, last_annotated_node);
3264       return;
3265     }
3266
3267   SET_EXPR_LOCUS (node, ggc_alloc (sizeof (location_t)));
3268   EXPR_LINENO (node) = line;
3269   EXPR_FILENAME (node) = file;
3270   last_annotated_node = EXPR_LOCUS (node);
3271 }
3272
3273 void
3274 annotate_with_locus (tree node, location_t locus)
3275 {
3276   annotate_with_file_line (node, locus.file, locus.line);
3277 }
3278 #endif
3279 \f
3280 /* Return a declaration like DDECL except that its DECL_ATTRIBUTES
3281    is ATTRIBUTE.  */
3282
3283 tree
3284 build_decl_attribute_variant (tree ddecl, tree attribute)
3285 {
3286   DECL_ATTRIBUTES (ddecl) = attribute;
3287   return ddecl;
3288 }
3289
3290 /* Borrowed from hashtab.c iterative_hash implementation.  */
3291 #define mix(a,b,c) \
3292 { \
3293   a -= b; a -= c; a ^= (c>>13); \
3294   b -= c; b -= a; b ^= (a<< 8); \
3295   c -= a; c -= b; c ^= ((b&0xffffffff)>>13); \
3296   a -= b; a -= c; a ^= ((c&0xffffffff)>>12); \
3297   b -= c; b -= a; b = (b ^ (a<<16)) & 0xffffffff; \
3298   c -= a; c -= b; c = (c ^ (b>> 5)) & 0xffffffff; \
3299   a -= b; a -= c; a = (a ^ (c>> 3)) & 0xffffffff; \
3300   b -= c; b -= a; b = (b ^ (a<<10)) & 0xffffffff; \
3301   c -= a; c -= b; c = (c ^ (b>>15)) & 0xffffffff; \
3302 }
3303
3304
3305 /* Produce good hash value combining VAL and VAL2.  */
3306 static inline hashval_t
3307 iterative_hash_hashval_t (hashval_t val, hashval_t val2)
3308 {
3309   /* the golden ratio; an arbitrary value.  */
3310   hashval_t a = 0x9e3779b9;
3311
3312   mix (a, val, val2);
3313   return val2;
3314 }
3315
3316 /* Produce good hash value combining PTR and VAL2.  */
3317 static inline hashval_t
3318 iterative_hash_pointer (void *ptr, hashval_t val2)
3319 {
3320   if (sizeof (ptr) == sizeof (hashval_t))
3321     return iterative_hash_hashval_t ((size_t) ptr, val2);
3322   else
3323     {
3324       hashval_t a = (hashval_t) (size_t) ptr;
3325       /* Avoid warnings about shifting of more than the width of the type on
3326          hosts that won't execute this path.  */
3327       int zero = 0;
3328       hashval_t b = (hashval_t) ((size_t) ptr >> (sizeof (hashval_t) * 8 + zero));
3329       mix (a, b, val2);
3330       return val2;
3331     }
3332 }
3333
3334 /* Produce good hash value combining VAL and VAL2.  */
3335 static inline hashval_t
3336 iterative_hash_host_wide_int (HOST_WIDE_INT val, hashval_t val2)
3337 {
3338   if (sizeof (HOST_WIDE_INT) == sizeof (hashval_t))
3339     return iterative_hash_hashval_t (val, val2);
3340   else
3341     {
3342       hashval_t a = (hashval_t) val;
3343       /* Avoid warnings about shifting of more than the width of the type on
3344          hosts that won't execute this path.  */
3345       int zero = 0;
3346       hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 8 + zero));
3347       mix (a, b, val2);
3348       if (sizeof (HOST_WIDE_INT) > 2 * sizeof (hashval_t))
3349         {
3350           hashval_t a = (hashval_t) (val >> (sizeof (hashval_t) * 16 + zero));
3351           hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 24 + zero));
3352           mix (a, b, val2);
3353         }
3354       return val2;
3355     }
3356 }
3357
3358 /* Return a type like TTYPE except that its TYPE_ATTRIBUTE
3359    is ATTRIBUTE.
3360
3361    Record such modified types already made so we don't make duplicates.  */
3362
3363 tree
3364 build_type_attribute_variant (tree ttype, tree attribute)
3365 {
3366   if (! attribute_list_equal (TYPE_ATTRIBUTES (ttype), attribute))
3367     {
3368       hashval_t hashcode = 0;
3369       tree ntype;
3370       enum tree_code code = TREE_CODE (ttype);
3371
3372       ntype = copy_node (ttype);
3373
3374       TYPE_POINTER_TO (ntype) = 0;
3375       TYPE_REFERENCE_TO (ntype) = 0;
3376       TYPE_ATTRIBUTES (ntype) = attribute;
3377
3378       /* Create a new main variant of TYPE.  */
3379       TYPE_MAIN_VARIANT (ntype) = ntype;
3380       TYPE_NEXT_VARIANT (ntype) = 0;
3381       set_type_quals (ntype, TYPE_UNQUALIFIED);
3382
3383       hashcode = iterative_hash_object (code, hashcode);
3384       if (TREE_TYPE (ntype))
3385         hashcode = iterative_hash_object (TYPE_HASH (TREE_TYPE (ntype)),
3386                                           hashcode);
3387       hashcode = attribute_hash_list (attribute, hashcode);
3388
3389       switch (TREE_CODE (ntype))
3390         {
3391         case FUNCTION_TYPE:
3392           hashcode = type_hash_list (TYPE_ARG_TYPES (ntype), hashcode);
3393           break;
3394         case ARRAY_TYPE:
3395           hashcode = iterative_hash_object (TYPE_HASH (TYPE_DOMAIN (ntype)),
3396                                             hashcode);
3397           break;
3398         case INTEGER_TYPE:
3399           hashcode = iterative_hash_object
3400             (TREE_INT_CST_LOW (TYPE_MAX_VALUE (ntype)), hashcode);
3401           hashcode = iterative_hash_object
3402             (TREE_INT_CST_HIGH (TYPE_MAX_VALUE (ntype)), hashcode);
3403           break;
3404         case REAL_TYPE:
3405           {
3406             unsigned int precision = TYPE_PRECISION (ntype);
3407             hashcode = iterative_hash_object (precision, hashcode);
3408           }
3409           break;
3410         default:
3411           break;
3412         }
3413
3414       ntype = type_hash_canon (hashcode, ntype);
3415       ttype = build_qualified_type (ntype, TYPE_QUALS (ttype));
3416     }
3417
3418   return ttype;
3419 }
3420
3421
3422 /* Return nonzero if IDENT is a valid name for attribute ATTR,
3423    or zero if not.
3424
3425    We try both `text' and `__text__', ATTR may be either one.  */
3426 /* ??? It might be a reasonable simplification to require ATTR to be only
3427    `text'.  One might then also require attribute lists to be stored in
3428    their canonicalized form.  */
3429
3430 static int
3431 is_attribute_with_length_p (const char *attr, int attr_len, tree ident)
3432 {
3433   int ident_len;
3434   const char *p;
3435
3436   if (TREE_CODE (ident) != IDENTIFIER_NODE)
3437     return 0;
3438
3439   p = IDENTIFIER_POINTER (ident);
3440   ident_len = IDENTIFIER_LENGTH (ident);
3441
3442   if (ident_len == attr_len
3443       && strcmp (attr, p) == 0)
3444     return 1;
3445
3446   /* If ATTR is `__text__', IDENT must be `text'; and vice versa.  */
3447   if (attr[0] == '_')
3448     {
3449       gcc_assert (attr[1] == '_');
3450       gcc_assert (attr[attr_len - 2] == '_');
3451       gcc_assert (attr[attr_len - 1] == '_');
3452       if (ident_len == attr_len - 4
3453           && strncmp (attr + 2, p, attr_len - 4) == 0)
3454         return 1;
3455     }
3456   else
3457     {
3458       if (ident_len == attr_len + 4
3459           && p[0] == '_' && p[1] == '_'
3460           && p[ident_len - 2] == '_' && p[ident_len - 1] == '_'
3461           && strncmp (attr, p + 2, attr_len) == 0)
3462         return 1;
3463     }
3464
3465   return 0;
3466 }
3467
3468 /* Return nonzero if IDENT is a valid name for attribute ATTR,
3469    or zero if not.
3470
3471    We try both `text' and `__text__', ATTR may be either one.  */
3472
3473 int
3474 is_attribute_p (const char *attr, tree ident)
3475 {
3476   return is_attribute_with_length_p (attr, strlen (attr), ident);
3477 }
3478
3479 /* Given an attribute name and a list of attributes, return a pointer to the
3480    attribute's list element if the attribute is part of the list, or NULL_TREE
3481    if not found.  If the attribute appears more than once, this only
3482    returns the first occurrence; the TREE_CHAIN of the return value should
3483    be passed back in if further occurrences are wanted.  */
3484
3485 tree
3486 lookup_attribute (const char *attr_name, tree list)
3487 {
3488   tree l;
3489   size_t attr_len = strlen (attr_name);
3490
3491   for (l = list; l; l = TREE_CHAIN (l))
3492     {
3493       gcc_assert (TREE_CODE (TREE_PURPOSE (l)) == IDENTIFIER_NODE);
3494       if (is_attribute_with_length_p (attr_name, attr_len, TREE_PURPOSE (l)))
3495         return l;
3496     }
3497
3498   return NULL_TREE;
3499 }
3500
3501 /* Remove any instances of attribute ATTR_NAME in LIST and return the
3502    modified list.  */
3503
3504 tree
3505 remove_attribute (const char *attr_name, tree list)
3506 {
3507   tree *p;
3508   size_t attr_len = strlen (attr_name);
3509
3510   for (p = &list; *p; )
3511     {
3512       tree l = *p;
3513       gcc_assert (TREE_CODE (TREE_PURPOSE (l)) == IDENTIFIER_NODE);
3514       if (is_attribute_with_length_p (attr_name, attr_len, TREE_PURPOSE (l)))
3515         *p = TREE_CHAIN (l);
3516       else
3517         p = &TREE_CHAIN (l);
3518     }
3519
3520   return list;
3521 }
3522
3523 /* Return an attribute list that is the union of a1 and a2.  */
3524
3525 tree
3526 merge_attributes (tree a1, tree a2)
3527 {
3528   tree attributes;
3529
3530   /* Either one unset?  Take the set one.  */
3531
3532   if ((attributes = a1) == 0)
3533     attributes = a2;
3534
3535   /* One that completely contains the other?  Take it.  */
3536
3537   else if (a2 != 0 && ! attribute_list_contained (a1, a2))
3538     {
3539       if (attribute_list_contained (a2, a1))
3540         attributes = a2;
3541       else
3542         {
3543           /* Pick the longest list, and hang on the other list.  */
3544
3545           if (list_length (a1) < list_length (a2))
3546             attributes = a2, a2 = a1;
3547
3548           for (; a2 != 0; a2 = TREE_CHAIN (a2))
3549             {
3550               tree a;
3551               for (a = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
3552                                          attributes);
3553                    a != NULL_TREE;
3554                    a = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
3555                                          TREE_CHAIN (a)))
3556                 {
3557                   if (simple_cst_equal (TREE_VALUE (a), TREE_VALUE (a2)) == 1)
3558                     break;
3559                 }
3560               if (a == NULL_TREE)
3561                 {
3562                   a1 = copy_node (a2);
3563                   TREE_CHAIN (a1) = attributes;
3564                   attributes = a1;
3565                 }
3566             }
3567         }
3568     }
3569   return attributes;
3570 }
3571
3572 /* Given types T1 and T2, merge their attributes and return
3573   the result.  */
3574
3575 tree
3576 merge_type_attributes (tree t1, tree t2)
3577 {
3578   return merge_attributes (TYPE_ATTRIBUTES (t1),
3579                            TYPE_ATTRIBUTES (t2));
3580 }
3581
3582 /* Given decls OLDDECL and NEWDECL, merge their attributes and return
3583    the result.  */
3584
3585 tree
3586 merge_decl_attributes (tree olddecl, tree newdecl)
3587 {
3588   return merge_attributes (DECL_ATTRIBUTES (olddecl),
3589                            DECL_ATTRIBUTES (newdecl));
3590 }
3591
3592 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
3593
3594 /* Specialization of merge_decl_attributes for various Windows targets.
3595
3596    This handles the following situation:
3597
3598      __declspec (dllimport) int foo;
3599      int foo;
3600
3601    The second instance of `foo' nullifies the dllimport.  */
3602
3603 tree
3604 merge_dllimport_decl_attributes (tree old, tree new)
3605 {
3606   tree a;
3607   int delete_dllimport_p = 1;
3608
3609   /* What we need to do here is remove from `old' dllimport if it doesn't
3610      appear in `new'.  dllimport behaves like extern: if a declaration is
3611      marked dllimport and a definition appears later, then the object
3612      is not dllimport'd.  We also remove a `new' dllimport if the old list
3613      contains dllexport:  dllexport always overrides dllimport, regardless
3614      of the order of declaration.  */
3615   if (!VAR_OR_FUNCTION_DECL_P (new))
3616     delete_dllimport_p = 0;
3617   else if (DECL_DLLIMPORT_P (new)
3618            && lookup_attribute ("dllexport", DECL_ATTRIBUTES (old)))
3619     {
3620       DECL_DLLIMPORT_P (new) = 0;
3621       warning (OPT_Wattributes, "%q+D already declared with dllexport attribute: "
3622               "dllimport ignored", new);
3623     }
3624   else if (DECL_DLLIMPORT_P (old) && !DECL_DLLIMPORT_P (new))
3625     {
3626       /* Warn about overriding a symbol that has already been used. eg:
3627            extern int __attribute__ ((dllimport)) foo;
3628            int* bar () {return &foo;}
3629            int foo;
3630       */
3631       if (TREE_USED (old))
3632         {
3633           warning (0, "%q+D redeclared without dllimport attribute "
3634                    "after being referenced with dll linkage", new);
3635           /* If we have used a variable's address with dllimport linkage,
3636               keep the old DECL_DLLIMPORT_P flag: the ADDR_EXPR using the
3637               decl may already have had TREE_INVARIANT and TREE_CONSTANT
3638               computed.
3639               We still remove the attribute so that assembler code refers
3640               to '&foo rather than '_imp__foo'.  */
3641           if (TREE_CODE (old) == VAR_DECL && TREE_ADDRESSABLE (old))
3642             DECL_DLLIMPORT_P (new) = 1;
3643         }
3644
3645       /* Let an inline definition silently override the external reference,
3646          but otherwise warn about attribute inconsistency.  */
3647       else if (TREE_CODE (new) == VAR_DECL
3648                || !DECL_DECLARED_INLINE_P (new))
3649         warning (OPT_Wattributes, "%q+D redeclared without dllimport attribute: "
3650                   "previous dllimport ignored", new);
3651     }
3652   else
3653     delete_dllimport_p = 0;
3654
3655   a = merge_attributes (DECL_ATTRIBUTES (old), DECL_ATTRIBUTES (new));
3656
3657   if (delete_dllimport_p)
3658     {
3659       tree prev, t;
3660       const size_t attr_len = strlen ("dllimport");
3661
3662       /* Scan the list for dllimport and delete it.  */
3663       for (prev = NULL_TREE, t = a; t; prev = t, t = TREE_CHAIN (t))
3664         {
3665           if (is_attribute_with_length_p ("dllimport", attr_len,
3666                                           TREE_PURPOSE (t)))
3667             {
3668               if (prev == NULL_TREE)
3669                 a = TREE_CHAIN (a);
3670               else
3671                 TREE_CHAIN (prev) = TREE_CHAIN (t);
3672               break;
3673             }
3674         }
3675     }
3676
3677   return a;
3678 }
3679
3680 /* Handle a "dllimport" or "dllexport" attribute; arguments as in
3681    struct attribute_spec.handler.  */
3682
3683 tree
3684 handle_dll_attribute (tree * pnode, tree name, tree args, int flags,
3685                       bool *no_add_attrs)
3686 {
3687   tree node = *pnode;
3688
3689   /* These attributes may apply to structure and union types being created,
3690      but otherwise should pass to the declaration involved.  */
3691   if (!DECL_P (node))
3692     {
3693       if (flags & ((int) ATTR_FLAG_DECL_NEXT | (int) ATTR_FLAG_FUNCTION_NEXT
3694                    | (int) ATTR_FLAG_ARRAY_NEXT))
3695         {
3696           *no_add_attrs = true;
3697           return tree_cons (name, args, NULL_TREE);
3698         }
3699       if (TREE_CODE (node) != RECORD_TYPE && TREE_CODE (node) != UNION_TYPE)
3700         {
3701           warning (OPT_Wattributes, "%qs attribute ignored",
3702                    IDENTIFIER_POINTER (name));
3703           *no_add_attrs = true;
3704         }
3705
3706       return NULL_TREE;
3707     }
3708
3709   if (TREE_CODE (node) != FUNCTION_DECL
3710       && TREE_CODE (node) != VAR_DECL)
3711     {
3712       *no_add_attrs = true;
3713       warning (OPT_Wattributes, "%qs attribute ignored",
3714                IDENTIFIER_POINTER (name));
3715       return NULL_TREE;
3716     }
3717
3718   /* Report error on dllimport ambiguities seen now before they cause
3719      any damage.  */
3720   else if (is_attribute_p ("dllimport", name))
3721     {
3722       /* Honor any target-specific overrides. */
3723       if (!targetm.valid_dllimport_attribute_p (node))
3724         *no_add_attrs = true;
3725
3726      else if (TREE_CODE (node) == FUNCTION_DECL
3727                 && DECL_DECLARED_INLINE_P (node))
3728         {
3729           warning (OPT_Wattributes, "inline function %q+D declared as "
3730                   " dllimport: attribute ignored", node);
3731           *no_add_attrs = true;
3732         }
3733       /* Like MS, treat definition of dllimported variables and
3734          non-inlined functions on declaration as syntax errors. */
3735      else if (TREE_CODE (node) == FUNCTION_DECL && DECL_INITIAL (node))
3736         {
3737           error ("function %q+D definition is marked dllimport", node);
3738           *no_add_attrs = true;
3739         }
3740
3741      else if (TREE_CODE (node) == VAR_DECL)
3742         {
3743           if (DECL_INITIAL (node))
3744             {
3745               error ("variable %q+D definition is marked dllimport",
3746                      node);
3747               *no_add_attrs = true;
3748             }
3749
3750           /* `extern' needn't be specified with dllimport.
3751              Specify `extern' now and hope for the best.  Sigh.  */
3752           DECL_EXTERNAL (node) = 1;
3753           /* Also, implicitly give dllimport'd variables declared within
3754              a function global scope, unless declared static.  */
3755           if (current_function_decl != NULL_TREE && !TREE_STATIC (node))
3756             TREE_PUBLIC (node) = 1;
3757         }
3758
3759       if (*no_add_attrs == false)
3760         DECL_DLLIMPORT_P (node) = 1;
3761     }
3762
3763   /*  Report error if symbol is not accessible at global scope.  */
3764   if (!TREE_PUBLIC (node)
3765       && (TREE_CODE (node) == VAR_DECL
3766           || TREE_CODE (node) == FUNCTION_DECL))
3767     {
3768       error ("external linkage required for symbol %q+D because of "
3769              "%qs attribute", node, IDENTIFIER_POINTER (name));
3770       *no_add_attrs = true;
3771     }
3772
3773   return NULL_TREE;
3774 }
3775
3776 #endif /* TARGET_DLLIMPORT_DECL_ATTRIBUTES  */
3777 \f
3778 /* Set the type qualifiers for TYPE to TYPE_QUALS, which is a bitmask
3779    of the various TYPE_QUAL values.  */
3780
3781 static void
3782 set_type_quals (tree type, int type_quals)
3783 {
3784   TYPE_READONLY (type) = (type_quals & TYPE_QUAL_CONST) != 0;
3785   TYPE_VOLATILE (type) = (type_quals & TYPE_QUAL_VOLATILE) != 0;
3786   TYPE_RESTRICT (type) = (type_quals & TYPE_QUAL_RESTRICT) != 0;
3787 }
3788
3789 /* Returns true iff cand is equivalent to base with type_quals.  */
3790
3791 bool
3792 check_qualified_type (tree cand, tree base, int type_quals)
3793 {
3794   return (TYPE_QUALS (cand) == type_quals
3795           && TYPE_NAME (cand) == TYPE_NAME (base)
3796           /* Apparently this is needed for Objective-C.  */
3797           && TYPE_CONTEXT (cand) == TYPE_CONTEXT (base)
3798           && attribute_list_equal (TYPE_ATTRIBUTES (cand),
3799                                    TYPE_ATTRIBUTES (base)));
3800 }
3801
3802 /* Return a version of the TYPE, qualified as indicated by the
3803    TYPE_QUALS, if one exists.  If no qualified version exists yet,
3804    return NULL_TREE.  */
3805
3806 tree
3807 get_qualified_type (tree type, int type_quals)
3808 {
3809   tree t;
3810
3811   if (TYPE_QUALS (type) == type_quals)
3812     return type;
3813
3814   /* Search the chain of variants to see if there is already one there just
3815      like the one we need to have.  If so, use that existing one.  We must
3816      preserve the TYPE_NAME, since there is code that depends on this.  */
3817   for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
3818     if (check_qualified_type (t, type, type_quals))
3819       return t;
3820
3821   return NULL_TREE;
3822 }
3823
3824 /* Like get_qualified_type, but creates the type if it does not
3825    exist.  This function never returns NULL_TREE.  */
3826
3827 tree
3828 build_qualified_type (tree type, int type_quals)
3829 {
3830   tree t;
3831
3832   /* See if we already have the appropriate qualified variant.  */
3833   t = get_qualified_type (type, type_quals);
3834
3835   /* If not, build it.  */
3836   if (!t)
3837     {
3838       t = build_variant_type_copy (type);
3839       set_type_quals (t, type_quals);
3840     }
3841
3842   return t;
3843 }
3844
3845 /* Create a new distinct copy of TYPE.  The new type is made its own
3846    MAIN_VARIANT.  */
3847
3848 tree
3849 build_distinct_type_copy (tree type)
3850 {
3851   tree t = copy_node (type);
3852
3853   TYPE_POINTER_TO (t) = 0;
3854   TYPE_REFERENCE_TO (t) = 0;
3855
3856   /* Make it its own variant.  */
3857   TYPE_MAIN_VARIANT (t) = t;
3858   TYPE_NEXT_VARIANT (t) = 0;
3859
3860   return t;
3861 }
3862
3863 /* Create a new variant of TYPE, equivalent but distinct.
3864    This is so the caller can modify it.  */
3865
3866 tree
3867 build_variant_type_copy (tree type)
3868 {
3869   tree t, m = TYPE_MAIN_VARIANT (type);
3870
3871   t = build_distinct_type_copy (type);
3872
3873   /* Add the new type to the chain of variants of TYPE.  */
3874   TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (m);
3875   TYPE_NEXT_VARIANT (m) = t;
3876   TYPE_MAIN_VARIANT (t) = m;
3877
3878   return t;
3879 }
3880 \f
3881 /* Return true if the from tree in both tree maps are equal.  */
3882
3883 int
3884 tree_map_eq (const void *va, const void *vb)
3885 {
3886   const struct tree_map  *a = va, *b = vb;
3887   return (a->from == b->from);
3888 }
3889
3890 /* Hash a from tree in a tree_map.  */
3891
3892 unsigned int
3893 tree_map_hash (const void *item)
3894 {
3895   return (((const struct tree_map *) item)->hash);
3896 }
3897
3898 /* Return true if this tree map structure is marked for garbage collection
3899    purposes.  We simply return true if the from tree is marked, so that this
3900    structure goes away when the from tree goes away.  */
3901
3902 int
3903 tree_map_marked_p (const void *p)
3904 {
3905   tree from = ((struct tree_map *) p)->from;
3906
3907   return ggc_marked_p (from);
3908 }
3909
3910 /* Return true if the trees in the tree_int_map *'s VA and VB are equal.  */
3911
3912 static int
3913 tree_int_map_eq (const void *va, const void *vb)
3914 {
3915   const struct tree_int_map  *a = va, *b = vb;
3916   return (a->from == b->from);
3917 }
3918
3919 /* Hash a from tree in the tree_int_map * ITEM.  */
3920
3921 static unsigned int
3922 tree_int_map_hash (const void *item)
3923 {
3924   return htab_hash_pointer (((const struct tree_int_map *)item)->from);
3925 }
3926
3927 /* Return true if this tree int map structure is marked for garbage collection
3928    purposes.  We simply return true if the from tree_int_map *P's from tree is marked, so that this
3929    structure goes away when the from tree goes away.  */
3930
3931 static int
3932 tree_int_map_marked_p (const void *p)
3933 {
3934   tree from = ((struct tree_int_map *) p)->from;
3935
3936   return ggc_marked_p (from);
3937 }
3938 /* Lookup an init priority for FROM, and return it if we find one.  */
3939
3940 unsigned short
3941 decl_init_priority_lookup (tree from)
3942 {
3943   struct tree_int_map *h, in;
3944   in.from = from;
3945
3946   h = htab_find_with_hash (init_priority_for_decl,
3947                            &in, htab_hash_pointer (from));
3948   if (h)
3949     return h->to;
3950   return 0;
3951 }
3952
3953 /* Insert a mapping FROM->TO in the init priority hashtable.  */
3954
3955 void
3956 decl_init_priority_insert (tree from, unsigned short to)
3957 {
3958   struct tree_int_map *h;
3959   void **loc;
3960
3961   h = ggc_alloc (sizeof (struct tree_int_map));
3962   h->from = from;
3963   h->to = to;
3964   loc = htab_find_slot_with_hash (init_priority_for_decl, h,
3965                                   htab_hash_pointer (from), INSERT);
3966   *(struct tree_int_map **) loc = h;
3967 }
3968
3969 /* Look up a restrict qualified base decl for FROM.  */
3970
3971 tree
3972 decl_restrict_base_lookup (tree from)
3973 {
3974   struct tree_map *h;
3975   struct tree_map in;
3976
3977   in.from = from;
3978   h = htab_find_with_hash (restrict_base_for_decl, &in,
3979                            htab_hash_pointer (from));
3980   return h ? h->to : NULL_TREE;
3981 }
3982
3983 /* Record the restrict qualified base TO for FROM.  */
3984
3985 void
3986 decl_restrict_base_insert (tree from, tree to)
3987 {
3988   struct tree_map *h;
3989   void **loc;
3990
3991   h = ggc_alloc (sizeof (struct tree_map));
3992   h->hash = htab_hash_pointer (from);
3993   h->from = from;
3994   h->to = to;
3995   loc = htab_find_slot_with_hash (restrict_base_for_decl, h, h->hash, INSERT);
3996   *(struct tree_map **) loc = h;
3997 }
3998
3999 /* Print out the statistics for the DECL_DEBUG_EXPR hash table.  */
4000
4001 static void
4002 print_debug_expr_statistics (void)
4003 {
4004   fprintf (stderr, "DECL_DEBUG_EXPR  hash: size %ld, %ld elements, %f collisions\n",
4005            (long) htab_size (debug_expr_for_decl),
4006            (long) htab_elements (debug_expr_for_decl),
4007            htab_collisions (debug_expr_for_decl));
4008 }
4009
4010 /* Print out the statistics for the DECL_VALUE_EXPR hash table.  */
4011
4012 static void
4013 print_value_expr_statistics (void)
4014 {
4015   fprintf (stderr, "DECL_VALUE_EXPR  hash: size %ld, %ld elements, %f collisions\n",
4016            (long) htab_size (value_expr_for_decl),
4017            (long) htab_elements (value_expr_for_decl),
4018            htab_collisions (value_expr_for_decl));
4019 }
4020
4021 /* Print out statistics for the RESTRICT_BASE_FOR_DECL hash table, but
4022    don't print anything if the table is empty.  */
4023
4024 static void
4025 print_restrict_base_statistics (void)
4026 {
4027   if (htab_elements (restrict_base_for_decl) != 0)
4028     fprintf (stderr,
4029              "RESTRICT_BASE    hash: size %ld, %ld elements, %f collisions\n",
4030              (long) htab_size (restrict_base_for_decl),
4031              (long) htab_elements (restrict_base_for_decl),
4032              htab_collisions (restrict_base_for_decl));
4033 }
4034
4035 /* Lookup a debug expression for FROM, and return it if we find one.  */
4036
4037 tree
4038 decl_debug_expr_lookup (tree from)
4039 {
4040   struct tree_map *h, in;
4041   in.from = from;
4042
4043   h = htab_find_with_hash (debug_expr_for_decl, &in, htab_hash_pointer (from));
4044   if (h)
4045     return h->to;
4046   return NULL_TREE;
4047 }
4048
4049 /* Insert a mapping FROM->TO in the debug expression hashtable.  */
4050
4051 void
4052 decl_debug_expr_insert (tree from, tree to)
4053 {
4054   struct tree_map *h;
4055   void **loc;
4056
4057   h = ggc_alloc (sizeof (struct tree_map));
4058   h->hash = htab_hash_pointer (from);
4059   h->from = from;
4060   h->to = to;
4061   loc = htab_find_slot_with_hash (debug_expr_for_decl, h, h->hash, INSERT);
4062   *(struct tree_map **) loc = h;
4063 }
4064
4065 /* Lookup a value expression for FROM, and return it if we find one.  */
4066
4067 tree
4068 decl_value_expr_lookup (tree from)
4069 {
4070   struct tree_map *h, in;
4071   in.from = from;
4072
4073   h = htab_find_with_hash (value_expr_for_decl, &in, htab_hash_pointer (from));
4074   if (h)
4075     return h->to;
4076   return NULL_TREE;
4077 }
4078
4079 /* Insert a mapping FROM->TO in the value expression hashtable.  */
4080
4081 void
4082 decl_value_expr_insert (tree from, tree to)
4083 {
4084   struct tree_map *h;
4085   void **loc;
4086
4087   h = ggc_alloc (sizeof (struct tree_map));
4088   h->hash = htab_hash_pointer (from);
4089   h->from = from;
4090   h->to = to;
4091   loc = htab_find_slot_with_hash (value_expr_for_decl, h, h->hash, INSERT);
4092   *(struct tree_map **) loc = h;
4093 }
4094
4095 /* Hashing of types so that we don't make duplicates.
4096    The entry point is `type_hash_canon'.  */
4097
4098 /* Compute a hash code for a list of types (chain of TREE_LIST nodes
4099    with types in the TREE_VALUE slots), by adding the hash codes
4100    of the individual types.  */
4101
4102 unsigned int
4103 type_hash_list (tree list, hashval_t hashcode)
4104 {
4105   tree tail;
4106
4107   for (tail = list; tail; tail = TREE_CHAIN (tail))
4108     if (TREE_VALUE (tail) != error_mark_node)
4109       hashcode = iterative_hash_object (TYPE_HASH (TREE_VALUE (tail)),
4110                                         hashcode);
4111
4112   return hashcode;
4113 }
4114
4115 /* These are the Hashtable callback functions.  */
4116
4117 /* Returns true iff the types are equivalent.  */
4118
4119 static int
4120 type_hash_eq (const void *va, const void *vb)
4121 {
4122   const struct type_hash *a = va, *b = vb;
4123
4124   /* First test the things that are the same for all types.  */
4125   if (a->hash != b->hash
4126       || TREE_CODE (a->type) != TREE_CODE (b->type)
4127       || TREE_TYPE (a->type) != TREE_TYPE (b->type)
4128       || !attribute_list_equal (TYPE_ATTRIBUTES (a->type),
4129                                  TYPE_ATTRIBUTES (b->type))
4130       || TYPE_ALIGN (a->type) != TYPE_ALIGN (b->type)
4131       || TYPE_MODE (a->type) != TYPE_MODE (b->type))
4132     return 0;
4133
4134   switch (TREE_CODE (a->type))
4135     {
4136     case VOID_TYPE:
4137     case COMPLEX_TYPE:
4138     case POINTER_TYPE:
4139     case REFERENCE_TYPE:
4140       return 1;
4141
4142     case VECTOR_TYPE:
4143       return TYPE_VECTOR_SUBPARTS (a->type) == TYPE_VECTOR_SUBPARTS (b->type);
4144
4145     case ENUMERAL_TYPE:
4146       if (TYPE_VALUES (a->type) != TYPE_VALUES (b->type)
4147           && !(TYPE_VALUES (a->type)
4148                && TREE_CODE (TYPE_VALUES (a->type)) == TREE_LIST
4149                && TYPE_VALUES (b->type)
4150                && TREE_CODE (TYPE_VALUES (b->type)) == TREE_LIST
4151                && type_list_equal (TYPE_VALUES (a->type),
4152                                    TYPE_VALUES (b->type))))
4153         return 0;
4154
4155       /* ... fall through ... */
4156
4157     case INTEGER_TYPE:
4158     case REAL_TYPE:
4159     case BOOLEAN_TYPE:
4160       return ((TYPE_MAX_VALUE (a->type) == TYPE_MAX_VALUE (b->type)
4161                || tree_int_cst_equal (TYPE_MAX_VALUE (a->type),
4162                                       TYPE_MAX_VALUE (b->type)))
4163               && (TYPE_MIN_VALUE (a->type) == TYPE_MIN_VALUE (b->type)
4164                   || tree_int_cst_equal (TYPE_MIN_VALUE (a->type),
4165                                          TYPE_MIN_VALUE (b->type))));
4166
4167     case OFFSET_TYPE:
4168       return TYPE_OFFSET_BASETYPE (a->type) == TYPE_OFFSET_BASETYPE (b->type);
4169
4170     case METHOD_TYPE:
4171       return (TYPE_METHOD_BASETYPE (a->type) == TYPE_METHOD_BASETYPE (b->type)
4172               && (TYPE_ARG_TYPES (a->type) == TYPE_ARG_TYPES (b->type)
4173                   || (TYPE_ARG_TYPES (a->type)
4174                       && TREE_CODE (TYPE_ARG_TYPES (a->type)) == TREE_LIST
4175                       && TYPE_ARG_TYPES (b->type)
4176                       && TREE_CODE (TYPE_ARG_TYPES (b->type)) == TREE_LIST
4177                       && type_list_equal (TYPE_ARG_TYPES (a->type),
4178                                           TYPE_ARG_TYPES (b->type)))));
4179
4180     case ARRAY_TYPE:
4181       return TYPE_DOMAIN (a->type) == TYPE_DOMAIN (b->type);
4182
4183     case RECORD_TYPE:
4184     case UNION_TYPE:
4185     case QUAL_UNION_TYPE:
4186       return (TYPE_FIELDS (a->type) == TYPE_FIELDS (b->type)
4187               || (TYPE_FIELDS (a->type)
4188                   && TREE_CODE (TYPE_FIELDS (a->type)) == TREE_LIST
4189                   && TYPE_FIELDS (b->type)
4190                   && TREE_CODE (TYPE_FIELDS (b->type)) == TREE_LIST
4191                   && type_list_equal (TYPE_FIELDS (a->type),
4192                                       TYPE_FIELDS (b->type))));
4193
4194     case FUNCTION_TYPE:
4195       return (TYPE_ARG_TYPES (a->type) == TYPE_ARG_TYPES (b->type)
4196               || (TYPE_ARG_TYPES (a->type)
4197                   && TREE_CODE (TYPE_ARG_TYPES (a->type)) == TREE_LIST
4198                   && TYPE_ARG_TYPES (b->type)
4199                   && TREE_CODE (TYPE_ARG_TYPES (b->type)) == TREE_LIST
4200                   && type_list_equal (TYPE_ARG_TYPES (a->type),
4201                                       TYPE_ARG_TYPES (b->type))));
4202
4203     default:
4204       return 0;
4205     }
4206 }
4207
4208 /* Return the cached hash value.  */
4209
4210 static hashval_t
4211 type_hash_hash (const void *item)
4212 {
4213   return ((const struct type_hash *) item)->hash;
4214 }
4215
4216 /* Look in the type hash table for a type isomorphic to TYPE.
4217    If one is found, return it.  Otherwise return 0.  */
4218
4219 tree
4220 type_hash_lookup (hashval_t hashcode, tree type)
4221 {
4222   struct type_hash *h, in;
4223
4224   /* The TYPE_ALIGN field of a type is set by layout_type(), so we
4225      must call that routine before comparing TYPE_ALIGNs.  */
4226   layout_type (type);
4227
4228   in.hash = hashcode;
4229   in.type = type;
4230
4231   h = htab_find_with_hash (type_hash_table, &in, hashcode);
4232   if (h)
4233     return h->type;
4234   return NULL_TREE;
4235 }
4236
4237 /* Add an entry to the type-hash-table
4238    for a type TYPE whose hash code is HASHCODE.  */
4239
4240 void
4241 type_hash_add (hashval_t hashcode, tree type)
4242 {
4243   struct type_hash *h;
4244   void **loc;
4245
4246   h = ggc_alloc (sizeof (struct type_hash));
4247   h->hash = hashcode;
4248   h->type = type;
4249   loc = htab_find_slot_with_hash (type_hash_table, h, hashcode, INSERT);
4250   *(struct type_hash **) loc = h;
4251 }
4252
4253 /* Given TYPE, and HASHCODE its hash code, return the canonical
4254    object for an identical type if one already exists.
4255    Otherwise, return TYPE, and record it as the canonical object.
4256
4257    To use this function, first create a type of the sort you want.
4258    Then compute its hash code from the fields of the type that
4259    make it different from other similar types.
4260    Then call this function and use the value.  */
4261
4262 tree
4263 type_hash_canon (unsigned int hashcode, tree type)
4264 {
4265   tree t1;
4266
4267   /* The hash table only contains main variants, so ensure that's what we're
4268      being passed.  */
4269   gcc_assert (TYPE_MAIN_VARIANT (type) == type);
4270
4271   if (!lang_hooks.types.hash_types)
4272     return type;
4273
4274   /* See if the type is in the hash table already.  If so, return it.
4275      Otherwise, add the type.  */
4276   t1 = type_hash_lookup (hashcode, type);
4277   if (t1 != 0)
4278     {
4279 #ifdef GATHER_STATISTICS
4280       tree_node_counts[(int) t_kind]--;
4281       tree_node_sizes[(int) t_kind] -= sizeof (struct tree_type);
4282 #endif
4283       return t1;
4284     }
4285   else
4286     {
4287       type_hash_add (hashcode, type);
4288       return type;
4289     }
4290 }
4291
4292 /* See if the data pointed to by the type hash table is marked.  We consider
4293    it marked if the type is marked or if a debug type number or symbol
4294    table entry has been made for the type.  This reduces the amount of
4295    debugging output and eliminates that dependency of the debug output on
4296    the number of garbage collections.  */
4297
4298 static int
4299 type_hash_marked_p (const void *p)
4300 {
4301   tree type = ((struct type_hash *) p)->type;
4302
4303   return ggc_marked_p (type) || TYPE_SYMTAB_POINTER (type);
4304 }
4305
4306 static void
4307 print_type_hash_statistics (void)
4308 {
4309   fprintf (stderr, "Type hash: size %ld, %ld elements, %f collisions\n",
4310            (long) htab_size (type_hash_table),
4311            (long) htab_elements (type_hash_table),
4312            htab_collisions (type_hash_table));
4313 }
4314
4315 /* Compute a hash code for a list of attributes (chain of TREE_LIST nodes
4316    with names in the TREE_PURPOSE slots and args in the TREE_VALUE slots),
4317    by adding the hash codes of the individual attributes.  */
4318
4319 unsigned int
4320 attribute_hash_list (tree list, hashval_t hashcode)
4321 {
4322   tree tail;
4323
4324   for (tail = list; tail; tail = TREE_CHAIN (tail))
4325     /* ??? Do we want to add in TREE_VALUE too? */
4326     hashcode = iterative_hash_object
4327       (IDENTIFIER_HASH_VALUE (TREE_PURPOSE (tail)), hashcode);
4328   return hashcode;
4329 }
4330
4331 /* Given two lists of attributes, return true if list l2 is
4332    equivalent to l1.  */
4333
4334 int
4335 attribute_list_equal (tree l1, tree l2)
4336 {
4337   return attribute_list_contained (l1, l2)
4338          && attribute_list_contained (l2, l1);
4339 }
4340
4341 /* Given two lists of attributes, return true if list L2 is
4342    completely contained within L1.  */
4343 /* ??? This would be faster if attribute names were stored in a canonicalized
4344    form.  Otherwise, if L1 uses `foo' and L2 uses `__foo__', the long method
4345    must be used to show these elements are equivalent (which they are).  */
4346 /* ??? It's not clear that attributes with arguments will always be handled
4347    correctly.  */
4348
4349 int
4350 attribute_list_contained (tree l1, tree l2)
4351 {
4352   tree t1, t2;
4353
4354   /* First check the obvious, maybe the lists are identical.  */
4355   if (l1 == l2)
4356     return 1;
4357
4358   /* Maybe the lists are similar.  */
4359   for (t1 = l1, t2 = l2;
4360        t1 != 0 && t2 != 0
4361         && TREE_PURPOSE (t1) == TREE_PURPOSE (t2)
4362         && TREE_VALUE (t1) == TREE_VALUE (t2);
4363        t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2));
4364
4365   /* Maybe the lists are equal.  */
4366   if (t1 == 0 && t2 == 0)
4367     return 1;
4368
4369   for (; t2 != 0; t2 = TREE_CHAIN (t2))
4370     {
4371       tree attr;
4372       for (attr = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (t2)), l1);
4373            attr != NULL_TREE;
4374            attr = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (t2)),
4375                                     TREE_CHAIN (attr)))
4376         {
4377           if (simple_cst_equal (TREE_VALUE (t2), TREE_VALUE (attr)) == 1)
4378             break;
4379         }
4380
4381       if (attr == 0)
4382         return 0;
4383
4384       if (simple_cst_equal (TREE_VALUE (t2), TREE_VALUE (attr)) != 1)
4385         return 0;
4386     }
4387
4388   return 1;
4389 }
4390
4391 /* Given two lists of types
4392    (chains of TREE_LIST nodes with types in the TREE_VALUE slots)
4393    return 1 if the lists contain the same types in the same order.
4394    Also, the TREE_PURPOSEs must match.  */
4395
4396 int
4397 type_list_equal (tree l1, tree l2)
4398 {
4399   tree t1, t2;
4400
4401   for (t1 = l1, t2 = l2; t1 && t2; t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2))
4402     if (TREE_VALUE (t1) != TREE_VALUE (t2)
4403         || (TREE_PURPOSE (t1) != TREE_PURPOSE (t2)
4404             && ! (1 == simple_cst_equal (TREE_PURPOSE (t1), TREE_PURPOSE (t2))
4405                   && (TREE_TYPE (TREE_PURPOSE (t1))
4406                       == TREE_TYPE (TREE_PURPOSE (t2))))))
4407       return 0;
4408
4409   return t1 == t2;
4410 }
4411
4412 /* Returns the number of arguments to the FUNCTION_TYPE or METHOD_TYPE
4413    given by TYPE.  If the argument list accepts variable arguments,
4414    then this function counts only the ordinary arguments.  */
4415
4416 int
4417 type_num_arguments (tree type)
4418 {
4419   int i = 0;
4420   tree t;
4421
4422   for (t = TYPE_ARG_TYPES (type); t; t = TREE_CHAIN (t))
4423     /* If the function does not take a variable number of arguments,
4424        the last element in the list will have type `void'.  */
4425     if (VOID_TYPE_P (TREE_VALUE (t)))
4426       break;
4427     else
4428       ++i;
4429
4430   return i;
4431 }
4432
4433 /* Nonzero if integer constants T1 and T2
4434    represent the same constant value.  */
4435
4436 int
4437 tree_int_cst_equal (tree t1, tree t2)
4438 {
4439   if (t1 == t2)
4440     return 1;
4441
4442   if (t1 == 0 || t2 == 0)
4443     return 0;
4444
4445   if (TREE_CODE (t1) == INTEGER_CST
4446       && TREE_CODE (t2) == INTEGER_CST
4447       && TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
4448       && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2))
4449     return 1;
4450
4451   return 0;
4452 }
4453
4454 /* Nonzero if integer constants T1 and T2 represent values that satisfy <.
4455    The precise way of comparison depends on their data type.  */
4456
4457 int
4458 tree_int_cst_lt (tree t1, tree t2)
4459 {
4460   if (t1 == t2)
4461     return 0;
4462
4463   if (TYPE_UNSIGNED (TREE_TYPE (t1)) != TYPE_UNSIGNED (TREE_TYPE (t2)))
4464     {
4465       int t1_sgn = tree_int_cst_sgn (t1);
4466       int t2_sgn = tree_int_cst_sgn (t2);
4467
4468       if (t1_sgn < t2_sgn)
4469         return 1;
4470       else if (t1_sgn > t2_sgn)
4471         return 0;
4472       /* Otherwise, both are non-negative, so we compare them as
4473          unsigned just in case one of them would overflow a signed
4474          type.  */
4475     }
4476   else if (!TYPE_UNSIGNED (TREE_TYPE (t1)))
4477     return INT_CST_LT (t1, t2);
4478
4479   return INT_CST_LT_UNSIGNED (t1, t2);
4480 }
4481
4482 /* Returns -1 if T1 < T2, 0 if T1 == T2, and 1 if T1 > T2.  */
4483
4484 int
4485 tree_int_cst_compare (tree t1, tree t2)
4486 {
4487   if (tree_int_cst_lt (t1, t2))
4488     return -1;
4489   else if (tree_int_cst_lt (t2, t1))
4490     return 1;
4491   else
4492     return 0;
4493 }
4494
4495 /* Return 1 if T is an INTEGER_CST that can be manipulated efficiently on
4496    the host.  If POS is zero, the value can be represented in a single
4497    HOST_WIDE_INT.  If POS is nonzero, the value must be non-negative and can
4498    be represented in a single unsigned HOST_WIDE_INT.  */
4499
4500 int
4501 host_integerp (tree t, int pos)
4502 {
4503   return (TREE_CODE (t) == INTEGER_CST
4504           && ((TREE_INT_CST_HIGH (t) == 0
4505                && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) >= 0)
4506               || (! pos && TREE_INT_CST_HIGH (t) == -1
4507                   && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0
4508                   && !TYPE_UNSIGNED (TREE_TYPE (t)))
4509               || (pos && TREE_INT_CST_HIGH (t) == 0)));
4510 }
4511
4512 /* Return the HOST_WIDE_INT least significant bits of T if it is an
4513    INTEGER_CST and there is no overflow.  POS is nonzero if the result must
4514    be non-negative.  We must be able to satisfy the above conditions.  */
4515
4516 HOST_WIDE_INT
4517 tree_low_cst (tree t, int pos)
4518 {
4519   gcc_assert (host_integerp (t, pos));
4520   return TREE_INT_CST_LOW (t);
4521 }
4522
4523 /* Return the most significant bit of the integer constant T.  */
4524
4525 int
4526 tree_int_cst_msb (tree t)
4527 {
4528   int prec;
4529   HOST_WIDE_INT h;
4530   unsigned HOST_WIDE_INT l;
4531
4532   /* Note that using TYPE_PRECISION here is wrong.  We care about the
4533      actual bits, not the (arbitrary) range of the type.  */
4534   prec = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (t))) - 1;
4535   rshift_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t), prec,
4536                  2 * HOST_BITS_PER_WIDE_INT, &l, &h, 0);
4537   return (l & 1) == 1;
4538 }
4539
4540 /* Return an indication of the sign of the integer constant T.
4541    The return value is -1 if T < 0, 0 if T == 0, and 1 if T > 0.
4542    Note that -1 will never be returned if T's type is unsigned.  */
4543
4544 int
4545 tree_int_cst_sgn (tree t)
4546 {
4547   if (TREE_INT_CST_LOW (t) == 0 && TREE_INT_CST_HIGH (t) == 0)
4548     return 0;
4549   else if (TYPE_UNSIGNED (TREE_TYPE (t)))
4550     return 1;
4551   else if (TREE_INT_CST_HIGH (t) < 0)
4552     return -1;
4553   else
4554     return 1;
4555 }
4556
4557 /* Compare two constructor-element-type constants.  Return 1 if the lists
4558    are known to be equal; otherwise return 0.  */
4559
4560 int
4561 simple_cst_list_equal (tree l1, tree l2)
4562 {
4563   while (l1 != NULL_TREE && l2 != NULL_TREE)
4564     {
4565       if (simple_cst_equal (TREE_VALUE (l1), TREE_VALUE (l2)) != 1)
4566         return 0;
4567
4568       l1 = TREE_CHAIN (l1);
4569       l2 = TREE_CHAIN (l2);
4570     }
4571
4572   return l1 == l2;
4573 }
4574
4575 /* Return truthvalue of whether T1 is the same tree structure as T2.
4576    Return 1 if they are the same.
4577    Return 0 if they are understandably different.
4578    Return -1 if either contains tree structure not understood by
4579    this function.  */
4580
4581 int
4582 simple_cst_equal (tree t1, tree t2)
4583 {
4584   enum tree_code code1, code2;
4585   int cmp;
4586   int i;
4587
4588   if (t1 == t2)
4589     return 1;
4590   if (t1 == 0 || t2 == 0)
4591     return 0;
4592
4593   code1 = TREE_CODE (t1);
4594   code2 = TREE_CODE (t2);
4595
4596   if (code1 == NOP_EXPR || code1 == CONVERT_EXPR || code1 == NON_LVALUE_EXPR)
4597     {
4598       if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
4599           || code2 == NON_LVALUE_EXPR)
4600         return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4601       else
4602         return simple_cst_equal (TREE_OPERAND (t1, 0), t2);
4603     }
4604
4605   else if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
4606            || code2 == NON_LVALUE_EXPR)
4607     return simple_cst_equal (t1, TREE_OPERAND (t2, 0));
4608
4609   if (code1 != code2)
4610     return 0;
4611
4612   switch (code1)
4613     {
4614     case INTEGER_CST:
4615       return (TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
4616               && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2));
4617
4618     case REAL_CST:
4619       return REAL_VALUES_IDENTICAL (TREE_REAL_CST (t1), TREE_REAL_CST (t2));
4620
4621     case STRING_CST:
4622       return (TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
4623               && ! memcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2),
4624                          TREE_STRING_LENGTH (t1)));
4625
4626     case CONSTRUCTOR:
4627       {
4628         unsigned HOST_WIDE_INT idx;
4629         VEC(constructor_elt, gc) *v1 = CONSTRUCTOR_ELTS (t1);
4630         VEC(constructor_elt, gc) *v2 = CONSTRUCTOR_ELTS (t2);
4631
4632         if (VEC_length (constructor_elt, v1) != VEC_length (constructor_elt, v2))
4633           return false;
4634
4635         for (idx = 0; idx < VEC_length (constructor_elt, v1); ++idx)
4636           /* ??? Should we handle also fields here? */
4637           if (!simple_cst_equal (VEC_index (constructor_elt, v1, idx)->value,
4638                                  VEC_index (constructor_elt, v2, idx)->value))
4639             return false;
4640         return true;
4641       }
4642
4643     case SAVE_EXPR:
4644       return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4645
4646     case CALL_EXPR:
4647       cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4648       if (cmp <= 0)
4649         return cmp;
4650       return
4651         simple_cst_list_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
4652
4653     case TARGET_EXPR:
4654       /* Special case: if either target is an unallocated VAR_DECL,
4655          it means that it's going to be unified with whatever the
4656          TARGET_EXPR is really supposed to initialize, so treat it
4657          as being equivalent to anything.  */
4658       if ((TREE_CODE (TREE_OPERAND (t1, 0)) == VAR_DECL
4659            && DECL_NAME (TREE_OPERAND (t1, 0)) == NULL_TREE
4660            && !DECL_RTL_SET_P (TREE_OPERAND (t1, 0)))
4661           || (TREE_CODE (TREE_OPERAND (t2, 0)) == VAR_DECL
4662               && DECL_NAME (TREE_OPERAND (t2, 0)) == NULL_TREE
4663               && !DECL_RTL_SET_P (TREE_OPERAND (t2, 0))))
4664         cmp = 1;
4665       else
4666         cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4667
4668       if (cmp <= 0)
4669         return cmp;
4670
4671       return simple_cst_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
4672
4673     case WITH_CLEANUP_EXPR:
4674       cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4675       if (cmp <= 0)
4676         return cmp;
4677
4678       return simple_cst_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t1, 1));
4679
4680     case COMPONENT_REF:
4681       if (TREE_OPERAND (t1, 1) == TREE_OPERAND (t2, 1))
4682         return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4683
4684       return 0;
4685
4686     case VAR_DECL:
4687     case PARM_DECL:
4688     case CONST_DECL:
4689     case FUNCTION_DECL:
4690       return 0;
4691
4692     default:
4693       break;
4694     }
4695
4696   /* This general rule works for most tree codes.  All exceptions should be
4697      handled above.  If this is a language-specific tree code, we can't
4698      trust what might be in the operand, so say we don't know
4699      the situation.  */
4700   if ((int) code1 >= (int) LAST_AND_UNUSED_TREE_CODE)
4701     return -1;
4702
4703   switch (TREE_CODE_CLASS (code1))
4704     {
4705     case tcc_unary:
4706     case tcc_binary:
4707     case tcc_comparison:
4708     case tcc_expression:
4709     case tcc_reference:
4710     case tcc_statement:
4711       cmp = 1;
4712       for (i = 0; i < TREE_CODE_LENGTH (code1); i++)
4713         {
4714           cmp = simple_cst_equal (TREE_OPERAND (t1, i), TREE_OPERAND (t2, i));
4715           if (cmp <= 0)
4716             return cmp;
4717         }
4718
4719       return cmp;
4720
4721     default:
4722       return -1;
4723     }
4724 }
4725
4726 /* Compare the value of T, an INTEGER_CST, with U, an unsigned integer value.
4727    Return -1, 0, or 1 if the value of T is less than, equal to, or greater
4728    than U, respectively.  */
4729
4730 int
4731 compare_tree_int (tree t, unsigned HOST_WIDE_INT u)
4732 {
4733   if (tree_int_cst_sgn (t) < 0)
4734     return -1;
4735   else if (TREE_INT_CST_HIGH (t) != 0)
4736     return 1;
4737   else if (TREE_INT_CST_LOW (t) == u)
4738     return 0;
4739   else if (TREE_INT_CST_LOW (t) < u)
4740     return -1;
4741   else
4742     return 1;
4743 }
4744
4745 /* Return true if CODE represents an associative tree code.  Otherwise
4746    return false.  */
4747 bool
4748 associative_tree_code (enum tree_code code)
4749 {
4750   switch (code)
4751     {
4752     case BIT_IOR_EXPR:
4753     case BIT_AND_EXPR:
4754     case BIT_XOR_EXPR:
4755     case PLUS_EXPR:
4756     case MULT_EXPR:
4757     case MIN_EXPR:
4758     case MAX_EXPR:
4759       return true;
4760
4761     default:
4762       break;
4763     }
4764   return false;
4765 }
4766
4767 /* Return true if CODE represents a commutative tree code.  Otherwise
4768    return false.  */
4769 bool
4770 commutative_tree_code (enum tree_code code)
4771 {
4772   switch (code)
4773     {
4774     case PLUS_EXPR:
4775     case MULT_EXPR:
4776     case MIN_EXPR:
4777     case MAX_EXPR:
4778     case BIT_IOR_EXPR:
4779     case BIT_XOR_EXPR:
4780     case BIT_AND_EXPR:
4781     case NE_EXPR:
4782     case EQ_EXPR:
4783     case UNORDERED_EXPR:
4784     case ORDERED_EXPR:
4785     case UNEQ_EXPR:
4786     case LTGT_EXPR:
4787     case TRUTH_AND_EXPR:
4788     case TRUTH_XOR_EXPR:
4789     case TRUTH_OR_EXPR:
4790       return true;
4791
4792     default:
4793       break;
4794     }
4795   return false;
4796 }
4797
4798 /* Generate a hash value for an expression.  This can be used iteratively
4799    by passing a previous result as the "val" argument.
4800
4801    This function is intended to produce the same hash for expressions which
4802    would compare equal using operand_equal_p.  */
4803
4804 hashval_t
4805 iterative_hash_expr (tree t, hashval_t val)
4806 {
4807   int i;
4808   enum tree_code code;
4809   char class;
4810
4811   if (t == NULL_TREE)
4812     return iterative_hash_pointer (t, val);
4813
4814   code = TREE_CODE (t);
4815
4816   switch (code)
4817     {
4818     /* Alas, constants aren't shared, so we can't rely on pointer
4819        identity.  */
4820     case INTEGER_CST:
4821       val = iterative_hash_host_wide_int (TREE_INT_CST_LOW (t), val);
4822       return iterative_hash_host_wide_int (TREE_INT_CST_HIGH (t), val);
4823     case REAL_CST:
4824       {
4825         unsigned int val2 = real_hash (TREE_REAL_CST_PTR (t));
4826
4827         return iterative_hash_hashval_t (val2, val);
4828       }
4829     case STRING_CST:
4830       return iterative_hash (TREE_STRING_POINTER (t),
4831                              TREE_STRING_LENGTH (t), val);
4832     case COMPLEX_CST:
4833       val = iterative_hash_expr (TREE_REALPART (t), val);
4834       return iterative_hash_expr (TREE_IMAGPART (t), val);
4835     case VECTOR_CST:
4836       return iterative_hash_expr (TREE_VECTOR_CST_ELTS (t), val);
4837
4838     case SSA_NAME:
4839     case VALUE_HANDLE:
4840       /* we can just compare by pointer.  */
4841       return iterative_hash_pointer (t, val);
4842
4843     case TREE_LIST:
4844       /* A list of expressions, for a CALL_EXPR or as the elements of a
4845          VECTOR_CST.  */
4846       for (; t; t = TREE_CHAIN (t))
4847         val = iterative_hash_expr (TREE_VALUE (t), val);
4848       return val;
4849     case CONSTRUCTOR:
4850       {
4851         unsigned HOST_WIDE_INT idx;
4852         tree field, value;
4853         FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), idx, field, value)
4854           {
4855             val = iterative_hash_expr (field, val);
4856             val = iterative_hash_expr (value, val);
4857           }
4858         return val;
4859       }
4860     case FUNCTION_DECL:
4861       /* When referring to a built-in FUNCTION_DECL, use the
4862          __builtin__ form.  Otherwise nodes that compare equal
4863          according to operand_equal_p might get different
4864          hash codes.  */
4865       if (DECL_BUILT_IN (t))
4866         {
4867           val = iterative_hash_pointer (built_in_decls[DECL_FUNCTION_CODE (t)],
4868                                       val);
4869           return val;
4870         }
4871       /* else FALL THROUGH */
4872     default:
4873       class = TREE_CODE_CLASS (code);
4874
4875       if (class == tcc_declaration)
4876         {
4877           /* DECL's have a unique ID */
4878           val = iterative_hash_host_wide_int (DECL_UID (t), val);
4879         }
4880       else
4881         {
4882           gcc_assert (IS_EXPR_CODE_CLASS (class));
4883
4884           val = iterative_hash_object (code, val);
4885
4886           /* Don't hash the type, that can lead to having nodes which
4887              compare equal according to operand_equal_p, but which
4888              have different hash codes.  */
4889           if (code == NOP_EXPR
4890               || code == CONVERT_EXPR
4891               || code == NON_LVALUE_EXPR)
4892             {
4893               /* Make sure to include signness in the hash computation.  */
4894               val += TYPE_UNSIGNED (TREE_TYPE (t));
4895               val = iterative_hash_expr (TREE_OPERAND (t, 0), val);
4896             }
4897
4898           else if (commutative_tree_code (code))
4899             {
4900               /* It's a commutative expression.  We want to hash it the same
4901                  however it appears.  We do this by first hashing both operands
4902                  and then rehashing based on the order of their independent
4903                  hashes.  */
4904               hashval_t one = iterative_hash_expr (TREE_OPERAND (t, 0), 0);
4905               hashval_t two = iterative_hash_expr (TREE_OPERAND (t, 1), 0);
4906               hashval_t t;
4907
4908               if (one > two)
4909                 t = one, one = two, two = t;
4910
4911               val = iterative_hash_hashval_t (one, val);
4912               val = iterative_hash_hashval_t (two, val);
4913             }
4914           else
4915             for (i = TREE_CODE_LENGTH (code) - 1; i >= 0; --i)
4916               val = iterative_hash_expr (TREE_OPERAND (t, i), val);
4917         }
4918       return val;
4919       break;
4920     }
4921 }
4922 \f
4923 /* Constructors for pointer, array and function types.
4924    (RECORD_TYPE, UNION_TYPE and ENUMERAL_TYPE nodes are
4925    constructed by language-dependent code, not here.)  */
4926
4927 /* Construct, lay out and return the type of pointers to TO_TYPE with
4928    mode MODE.  If CAN_ALIAS_ALL is TRUE, indicate this type can
4929    reference all of memory. If such a type has already been
4930    constructed, reuse it.  */
4931
4932 tree
4933 build_pointer_type_for_mode (tree to_type, enum machine_mode mode,
4934                              bool can_alias_all)
4935 {
4936   tree t;
4937
4938   if (to_type == error_mark_node)
4939     return error_mark_node;
4940
4941   /* In some cases, languages will have things that aren't a POINTER_TYPE
4942      (such as a RECORD_TYPE for fat pointers in Ada) as TYPE_POINTER_TO.
4943      In that case, return that type without regard to the rest of our
4944      operands.
4945
4946      ??? This is a kludge, but consistent with the way this function has
4947      always operated and there doesn't seem to be a good way to avoid this
4948      at the moment.  */
4949   if (TYPE_POINTER_TO (to_type) != 0
4950       && TREE_CODE (TYPE_POINTER_TO (to_type)) != POINTER_TYPE)
4951     return TYPE_POINTER_TO (to_type);
4952
4953   /* First, if we already have a type for pointers to TO_TYPE and it's
4954      the proper mode, use it.  */
4955   for (t = TYPE_POINTER_TO (to_type); t; t = TYPE_NEXT_PTR_TO (t))
4956     if (TYPE_MODE (t) == mode && TYPE_REF_CAN_ALIAS_ALL (t) == can_alias_all)
4957       return t;
4958
4959   t = make_node (POINTER_TYPE);
4960
4961   TREE_TYPE (t) = to_type;
4962   TYPE_MODE (t) = mode;
4963   TYPE_REF_CAN_ALIAS_ALL (t) = can_alias_all;
4964   TYPE_NEXT_PTR_TO (t) = TYPE_POINTER_TO (to_type);
4965   TYPE_POINTER_TO (to_type) = t;
4966
4967   /* Lay out the type.  This function has many callers that are concerned
4968      with expression-construction, and this simplifies them all.  */
4969   layout_type (t);
4970
4971   return t;
4972 }
4973
4974 /* By default build pointers in ptr_mode.  */
4975
4976 tree
4977 build_pointer_type (tree to_type)
4978 {
4979   return build_pointer_type_for_mode (to_type, ptr_mode, false);
4980 }
4981
4982 /* Same as build_pointer_type_for_mode, but for REFERENCE_TYPE.  */
4983
4984 tree
4985 build_reference_type_for_mode (tree to_type, enum machine_mode mode,
4986                                bool can_alias_all)
4987 {
4988   tree t;
4989
4990   /* In some cases, languages will have things that aren't a REFERENCE_TYPE
4991      (such as a RECORD_TYPE for fat pointers in Ada) as TYPE_REFERENCE_TO.
4992      In that case, return that type without regard to the rest of our
4993      operands.
4994
4995      ??? This is a kludge, but consistent with the way this function has
4996      always operated and there doesn't seem to be a good way to avoid this
4997      at the moment.  */
4998   if (TYPE_REFERENCE_TO (to_type) != 0
4999       && TREE_CODE (TYPE_REFERENCE_TO (to_type)) != REFERENCE_TYPE)
5000     return TYPE_REFERENCE_TO (to_type);
5001
5002   /* First, if we already have a type for pointers to TO_TYPE and it's
5003      the proper mode, use it.  */
5004   for (t = TYPE_REFERENCE_TO (to_type); t; t = TYPE_NEXT_REF_TO (t))
5005     if (TYPE_MODE (t) == mode && TYPE_REF_CAN_ALIAS_ALL (t) == can_alias_all)
5006       return t;
5007
5008   t = make_node (REFERENCE_TYPE);
5009
5010   TREE_TYPE (t) = to_type;
5011   TYPE_MODE (t) = mode;
5012   TYPE_REF_CAN_ALIAS_ALL (t) = can_alias_all;
5013   TYPE_NEXT_REF_TO (t) = TYPE_REFERENCE_TO (to_type);
5014   TYPE_REFERENCE_TO (to_type) = t;
5015
5016   layout_type (t);
5017
5018   return t;
5019 }
5020
5021
5022 /* Build the node for the type of references-to-TO_TYPE by default
5023    in ptr_mode.  */
5024
5025 tree
5026 build_reference_type (tree to_type)
5027 {
5028   return build_reference_type_for_mode (to_type, ptr_mode, false);
5029 }
5030
5031 /* Build a type that is compatible with t but has no cv quals anywhere
5032    in its type, thus
5033
5034    const char *const *const *  ->  char ***.  */
5035
5036 tree
5037 build_type_no_quals (tree t)
5038 {
5039   switch (TREE_CODE (t))
5040     {
5041     case POINTER_TYPE:
5042       return build_pointer_type_for_mode (build_type_no_quals (TREE_TYPE (t)),
5043                                           TYPE_MODE (t),
5044                                           TYPE_REF_CAN_ALIAS_ALL (t));
5045     case REFERENCE_TYPE:
5046       return
5047         build_reference_type_for_mode (build_type_no_quals (TREE_TYPE (t)),
5048                                        TYPE_MODE (t),
5049                                        TYPE_REF_CAN_ALIAS_ALL (t));
5050     default:
5051       return TYPE_MAIN_VARIANT (t);
5052     }
5053 }
5054
5055 /* Create a type of integers to be the TYPE_DOMAIN of an ARRAY_TYPE.
5056    MAXVAL should be the maximum value in the domain
5057    (one less than the length of the array).
5058
5059    The maximum value that MAXVAL can have is INT_MAX for a HOST_WIDE_INT.
5060    We don't enforce this limit, that is up to caller (e.g. language front end).
5061    The limit exists because the result is a signed type and we don't handle
5062    sizes that use more than one HOST_WIDE_INT.  */
5063
5064 tree
5065 build_index_type (tree maxval)
5066 {
5067   tree itype = make_node (INTEGER_TYPE);
5068
5069   TREE_TYPE (itype) = sizetype;
5070   TYPE_PRECISION (itype) = TYPE_PRECISION (sizetype);
5071   TYPE_MIN_VALUE (itype) = size_zero_node;
5072   TYPE_MAX_VALUE (itype) = fold_convert (sizetype, maxval);
5073   TYPE_MODE (itype) = TYPE_MODE (sizetype);
5074   TYPE_SIZE (itype) = TYPE_SIZE (sizetype);
5075   TYPE_SIZE_UNIT (itype) = TYPE_SIZE_UNIT (sizetype);
5076   TYPE_ALIGN (itype) = TYPE_ALIGN (sizetype);
5077   TYPE_USER_ALIGN (itype) = TYPE_USER_ALIGN (sizetype);
5078
5079   if (host_integerp (maxval, 1))
5080     return type_hash_canon (tree_low_cst (maxval, 1), itype);
5081   else
5082     return itype;
5083 }
5084
5085 /* Builds a signed or unsigned integer type of precision PRECISION.
5086    Used for C bitfields whose precision does not match that of
5087    built-in target types.  */
5088 tree
5089 build_nonstandard_integer_type (unsigned HOST_WIDE_INT precision,
5090                                 int unsignedp)
5091 {
5092   tree itype = make_node (INTEGER_TYPE);
5093
5094   TYPE_PRECISION (itype) = precision;
5095
5096   if (unsignedp)
5097     fixup_unsigned_type (itype);
5098   else
5099     fixup_signed_type (itype);
5100
5101   if (host_integerp (TYPE_MAX_VALUE (itype), 1))
5102     return type_hash_canon (tree_low_cst (TYPE_MAX_VALUE (itype), 1), itype);
5103
5104   return itype;
5105 }
5106
5107 /* Create a range of some discrete type TYPE (an INTEGER_TYPE,
5108    ENUMERAL_TYPE or BOOLEAN_TYPE), with low bound LOWVAL and
5109    high bound HIGHVAL.  If TYPE is NULL, sizetype is used.  */
5110
5111 tree
5112 build_range_type (tree type, tree lowval, tree highval)
5113 {
5114   tree itype = make_node (INTEGER_TYPE);
5115
5116   TREE_TYPE (itype) = type;
5117   if (type == NULL_TREE)
5118     type = sizetype;
5119
5120   TYPE_MIN_VALUE (itype) = fold_convert (type, lowval);
5121   TYPE_MAX_VALUE (itype) = highval ? fold_convert (type, highval) : NULL;
5122
5123   TYPE_PRECISION (itype) = TYPE_PRECISION (type);
5124   TYPE_MODE (itype) = TYPE_MODE (type);
5125   TYPE_SIZE (itype) = TYPE_SIZE (type);
5126   TYPE_SIZE_UNIT (itype) = TYPE_SIZE_UNIT (type);
5127   TYPE_ALIGN (itype) = TYPE_ALIGN (type);
5128   TYPE_USER_ALIGN (itype) = TYPE_USER_ALIGN (type);
5129
5130   if (host_integerp (lowval, 0) && highval != 0 && host_integerp (highval, 0))
5131     return type_hash_canon (tree_low_cst (highval, 0)
5132                             - tree_low_cst (lowval, 0),
5133                             itype);
5134   else
5135     return itype;
5136 }
5137
5138 /* Just like build_index_type, but takes lowval and highval instead
5139    of just highval (maxval).  */
5140
5141 tree
5142 build_index_2_type (tree lowval, tree highval)
5143 {
5144   return build_range_type (sizetype, lowval, highval);
5145 }
5146
5147 /* Construct, lay out and return the type of arrays of elements with ELT_TYPE
5148    and number of elements specified by the range of values of INDEX_TYPE.
5149    If such a type has already been constructed, reuse it.  */
5150
5151 tree
5152 build_array_type (tree elt_type, tree index_type)
5153 {
5154   tree t;
5155   hashval_t hashcode = 0;
5156
5157   if (TREE_CODE (elt_type) == FUNCTION_TYPE)
5158     {
5159       error ("arrays of functions are not meaningful");
5160       elt_type = integer_type_node;
5161     }
5162
5163   t = make_node (ARRAY_TYPE);
5164   TREE_TYPE (t) = elt_type;
5165   TYPE_DOMAIN (t) = index_type;
5166
5167   if (index_type == 0)
5168     {
5169       tree save = t;
5170       hashcode = iterative_hash_object (TYPE_HASH (elt_type), hashcode);
5171       t = type_hash_canon (hashcode, t);
5172       if (save == t)
5173         layout_type (t);
5174       return t;
5175     }
5176
5177   hashcode = iterative_hash_object (TYPE_HASH (elt_type), hashcode);
5178   hashcode = iterative_hash_object (TYPE_HASH (index_type), hashcode);
5179   t = type_hash_canon (hashcode, t);
5180
5181   if (!COMPLETE_TYPE_P (t))
5182     layout_type (t);
5183   return t;
5184 }
5185
5186 /* Return the TYPE of the elements comprising
5187    the innermost dimension of ARRAY.  */
5188
5189 tree
5190 get_inner_array_type (tree array)
5191 {
5192   tree type = TREE_TYPE (array);
5193
5194   while (TREE_CODE (type) == ARRAY_TYPE)
5195     type = TREE_TYPE (type);
5196
5197   return type;
5198 }
5199
5200 /* Construct, lay out and return
5201    the type of functions returning type VALUE_TYPE
5202    given arguments of types ARG_TYPES.
5203    ARG_TYPES is a chain of TREE_LIST nodes whose TREE_VALUEs
5204    are data type nodes for the arguments of the function.
5205    If such a type has already been constructed, reuse it.  */
5206
5207 tree
5208 build_function_type (tree value_type, tree arg_types)
5209 {
5210   tree t;
5211   hashval_t hashcode = 0;
5212
5213   if (TREE_CODE (value_type) == FUNCTION_TYPE)
5214     {
5215       error ("function return type cannot be function");
5216       value_type = integer_type_node;
5217     }
5218
5219   /* Make a node of the sort we want.  */
5220   t = make_node (FUNCTION_TYPE);
5221   TREE_TYPE (t) = value_type;
5222   TYPE_ARG_TYPES (t) = arg_types;
5223
5224   /* If we already have such a type, use the old one.  */
5225   hashcode = iterative_hash_object (TYPE_HASH (value_type), hashcode);
5226   hashcode = type_hash_list (arg_types, hashcode);
5227   t = type_hash_canon (hashcode, t);
5228
5229   if (!COMPLETE_TYPE_P (t))
5230     layout_type (t);
5231   return t;
5232 }
5233
5234 /* Build a function type.  The RETURN_TYPE is the type returned by the
5235    function.  If additional arguments are provided, they are
5236    additional argument types.  The list of argument types must always
5237    be terminated by NULL_TREE.  */
5238
5239 tree
5240 build_function_type_list (tree return_type, ...)
5241 {
5242   tree t, args, last;
5243   va_list p;
5244
5245   va_start (p, return_type);
5246
5247   t = va_arg (p, tree);
5248   for (args = NULL_TREE; t != NULL_TREE; t = va_arg (p, tree))
5249     args = tree_cons (NULL_TREE, t, args);
5250
5251   if (args == NULL_TREE)
5252     args = void_list_node;
5253   else
5254     {
5255       last = args;
5256       args = nreverse (args);
5257       TREE_CHAIN (last) = void_list_node;
5258     }
5259   args = build_function_type (return_type, args);
5260
5261   va_end (p);
5262   return args;
5263 }
5264
5265 /* Build a METHOD_TYPE for a member of BASETYPE.  The RETTYPE (a TYPE)
5266    and ARGTYPES (a TREE_LIST) are the return type and arguments types
5267    for the method.  An implicit additional parameter (of type
5268    pointer-to-BASETYPE) is added to the ARGTYPES.  */
5269
5270 tree
5271 build_method_type_directly (tree basetype,
5272                             tree rettype,
5273                             tree argtypes)
5274 {
5275   tree t;
5276   tree ptype;
5277   int hashcode = 0;
5278
5279   /* Make a node of the sort we want.  */
5280   t = make_node (METHOD_TYPE);
5281
5282   TYPE_METHOD_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
5283   TREE_TYPE (t) = rettype;
5284   ptype = build_pointer_type (basetype);
5285
5286   /* The actual arglist for this function includes a "hidden" argument
5287      which is "this".  Put it into the list of argument types.  */
5288   argtypes = tree_cons (NULL_TREE, ptype, argtypes);
5289   TYPE_ARG_TYPES (t) = argtypes;
5290
5291   /* If we already have such a type, use the old one.  */
5292   hashcode = iterative_hash_object (TYPE_HASH (basetype), hashcode);
5293   hashcode = iterative_hash_object (TYPE_HASH (rettype), hashcode);
5294   hashcode = type_hash_list (argtypes, hashcode);
5295   t = type_hash_canon (hashcode, t);
5296
5297   if (!COMPLETE_TYPE_P (t))
5298     layout_type (t);
5299
5300   return t;
5301 }
5302
5303 /* Construct, lay out and return the type of methods belonging to class
5304    BASETYPE and whose arguments and values are described by TYPE.
5305    If that type exists already, reuse it.
5306    TYPE must be a FUNCTION_TYPE node.  */
5307
5308 tree
5309 build_method_type (tree basetype, tree type)
5310 {
5311   gcc_assert (TREE_CODE (type) == FUNCTION_TYPE);
5312
5313   return build_method_type_directly (basetype,
5314                                      TREE_TYPE (type),
5315                                      TYPE_ARG_TYPES (type));
5316 }
5317
5318 /* Construct, lay out and return the type of offsets to a value
5319    of type TYPE, within an object of type BASETYPE.
5320    If a suitable offset type exists already, reuse it.  */
5321
5322 tree
5323 build_offset_type (tree basetype, tree type)
5324 {
5325   tree t;
5326   hashval_t hashcode = 0;
5327
5328   /* Make a node of the sort we want.  */
5329   t = make_node (OFFSET_TYPE);
5330
5331   TYPE_OFFSET_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
5332   TREE_TYPE (t) = type;
5333
5334   /* If we already have such a type, use the old one.  */
5335   hashcode = iterative_hash_object (TYPE_HASH (basetype), hashcode);
5336   hashcode = iterative_hash_object (TYPE_HASH (type), hashcode);
5337   t = type_hash_canon (hashcode, t);
5338
5339   if (!COMPLETE_TYPE_P (t))
5340     layout_type (t);
5341
5342   return t;
5343 }
5344
5345 /* Create a complex type whose components are COMPONENT_TYPE.  */
5346
5347 tree
5348 build_complex_type (tree component_type)
5349 {
5350   tree t;
5351   hashval_t hashcode;
5352
5353   /* Make a node of the sort we want.  */
5354   t = make_node (COMPLEX_TYPE);
5355
5356   TREE_TYPE (t) = TYPE_MAIN_VARIANT (component_type);
5357
5358   /* If we already have such a type, use the old one.  */
5359   hashcode = iterative_hash_object (TYPE_HASH (component_type), 0);
5360   t = type_hash_canon (hashcode, t);
5361
5362   if (!COMPLETE_TYPE_P (t))
5363     layout_type (t);
5364
5365   /* If we are writing Dwarf2 output we need to create a name,
5366      since complex is a fundamental type.  */
5367   if ((write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
5368       && ! TYPE_NAME (t))
5369     {
5370       const char *name;
5371       if (component_type == char_type_node)
5372         name = "complex char";
5373       else if (component_type == signed_char_type_node)
5374         name = "complex signed char";
5375       else if (component_type == unsigned_char_type_node)
5376         name = "complex unsigned char";
5377       else if (component_type == short_integer_type_node)
5378         name = "complex short int";
5379       else if (component_type == short_unsigned_type_node)
5380         name = "complex short unsigned int";
5381       else if (component_type == integer_type_node)
5382         name = "complex int";
5383       else if (component_type == unsigned_type_node)
5384         name = "complex unsigned int";
5385       else if (component_type == long_integer_type_node)
5386         name = "complex long int";
5387       else if (component_type == long_unsigned_type_node)
5388         name = "complex long unsigned int";
5389       else if (component_type == long_long_integer_type_node)
5390         name = "complex long long int";
5391       else if (component_type == long_long_unsigned_type_node)
5392         name = "complex long long unsigned int";
5393       else
5394         name = 0;
5395
5396       if (name != 0)
5397         TYPE_NAME (t) = get_identifier (name);
5398     }
5399
5400   return build_qualified_type (t, TYPE_QUALS (component_type));
5401 }
5402 \f
5403 /* Return OP, stripped of any conversions to wider types as much as is safe.
5404    Converting the value back to OP's type makes a value equivalent to OP.
5405
5406    If FOR_TYPE is nonzero, we return a value which, if converted to
5407    type FOR_TYPE, would be equivalent to converting OP to type FOR_TYPE.
5408
5409    If FOR_TYPE is nonzero, unaligned bit-field references may be changed to the
5410    narrowest type that can hold the value, even if they don't exactly fit.
5411    Otherwise, bit-field references are changed to a narrower type
5412    only if they can be fetched directly from memory in that type.
5413
5414    OP must have integer, real or enumeral type.  Pointers are not allowed!
5415
5416    There are some cases where the obvious value we could return
5417    would regenerate to OP if converted to OP's type,
5418    but would not extend like OP to wider types.
5419    If FOR_TYPE indicates such extension is contemplated, we eschew such values.
5420    For example, if OP is (unsigned short)(signed char)-1,
5421    we avoid returning (signed char)-1 if FOR_TYPE is int,
5422    even though extending that to an unsigned short would regenerate OP,
5423    since the result of extending (signed char)-1 to (int)
5424    is different from (int) OP.  */
5425
5426 tree
5427 get_unwidened (tree op, tree for_type)
5428 {
5429   /* Set UNS initially if converting OP to FOR_TYPE is a zero-extension.  */
5430   tree type = TREE_TYPE (op);
5431   unsigned final_prec
5432     = TYPE_PRECISION (for_type != 0 ? for_type : type);
5433   int uns
5434     = (for_type != 0 && for_type != type
5435        && final_prec > TYPE_PRECISION (type)
5436        && TYPE_UNSIGNED (type));
5437   tree win = op;
5438
5439   while (TREE_CODE (op) == NOP_EXPR
5440          || TREE_CODE (op) == CONVERT_EXPR)
5441     {
5442       int bitschange;
5443
5444       /* TYPE_PRECISION on vector types has different meaning
5445          (TYPE_VECTOR_SUBPARTS) and casts from vectors are view conversions,
5446          so avoid them here.  */
5447       if (TREE_CODE (TREE_TYPE (TREE_OPERAND (op, 0))) == VECTOR_TYPE)
5448         break;
5449
5450       bitschange = TYPE_PRECISION (TREE_TYPE (op))
5451                    - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0)));
5452
5453       /* Truncations are many-one so cannot be removed.
5454          Unless we are later going to truncate down even farther.  */
5455       if (bitschange < 0
5456           && final_prec > TYPE_PRECISION (TREE_TYPE (op)))
5457         break;
5458
5459       /* See what's inside this conversion.  If we decide to strip it,
5460          we will set WIN.  */
5461       op = TREE_OPERAND (op, 0);
5462
5463       /* If we have not stripped any zero-extensions (uns is 0),
5464          we can strip any kind of extension.
5465          If we have previously stripped a zero-extension,
5466          only zero-extensions can safely be stripped.
5467          Any extension can be stripped if the bits it would produce
5468          are all going to be discarded later by truncating to FOR_TYPE.  */
5469
5470       if (bitschange > 0)
5471         {
5472           if (! uns || final_prec <= TYPE_PRECISION (TREE_TYPE (op)))
5473             win = op;
5474           /* TYPE_UNSIGNED says whether this is a zero-extension.
5475              Let's avoid computing it if it does not affect WIN
5476              and if UNS will not be needed again.  */
5477           if ((uns
5478                || TREE_CODE (op) == NOP_EXPR
5479                || TREE_CODE (op) == CONVERT_EXPR)
5480               && TYPE_UNSIGNED (TREE_TYPE (op)))
5481             {
5482               uns = 1;
5483               win = op;
5484             }
5485         }
5486     }
5487
5488   if (TREE_CODE (op) == COMPONENT_REF
5489       /* Since type_for_size always gives an integer type.  */
5490       && TREE_CODE (type) != REAL_TYPE
5491       /* Don't crash if field not laid out yet.  */
5492       && DECL_SIZE (TREE_OPERAND (op, 1)) != 0
5493       && host_integerp (DECL_SIZE (TREE_OPERAND (op, 1)), 1))
5494     {
5495       unsigned int innerprec
5496         = tree_low_cst (DECL_SIZE (TREE_OPERAND (op, 1)), 1);
5497       int unsignedp = (DECL_UNSIGNED (TREE_OPERAND (op, 1))
5498                        || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op, 1))));
5499       type = lang_hooks.types.type_for_size (innerprec, unsignedp);
5500
5501       /* We can get this structure field in the narrowest type it fits in.
5502          If FOR_TYPE is 0, do this only for a field that matches the
5503          narrower type exactly and is aligned for it
5504          The resulting extension to its nominal type (a fullword type)
5505          must fit the same conditions as for other extensions.  */
5506
5507       if (type != 0
5508           && INT_CST_LT_UNSIGNED (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (op)))
5509           && (for_type || ! DECL_BIT_FIELD (TREE_OPERAND (op, 1)))
5510           && (! uns || final_prec <= innerprec || unsignedp))
5511         {
5512           win = build3 (COMPONENT_REF, type, TREE_OPERAND (op, 0),
5513                         TREE_OPERAND (op, 1), NULL_TREE);
5514           TREE_SIDE_EFFECTS (win) = TREE_SIDE_EFFECTS (op);
5515           TREE_THIS_VOLATILE (win) = TREE_THIS_VOLATILE (op);
5516         }
5517     }
5518
5519   return win;
5520 }
5521 \f
5522 /* Return OP or a simpler expression for a narrower value
5523    which can be sign-extended or zero-extended to give back OP.
5524    Store in *UNSIGNEDP_PTR either 1 if the value should be zero-extended
5525    or 0 if the value should be sign-extended.  */
5526
5527 tree
5528 get_narrower (tree op, int *unsignedp_ptr)
5529 {
5530   int uns = 0;
5531   int first = 1;
5532   tree win = op;
5533   bool integral_p = INTEGRAL_TYPE_P (TREE_TYPE (op));
5534
5535   while (TREE_CODE (op) == NOP_EXPR)
5536     {
5537       int bitschange
5538         = (TYPE_PRECISION (TREE_TYPE (op))
5539            - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0))));
5540
5541       /* Truncations are many-one so cannot be removed.  */
5542       if (bitschange < 0)
5543         break;
5544
5545       /* See what's inside this conversion.  If we decide to strip it,
5546          we will set WIN.  */
5547
5548       if (bitschange > 0)
5549         {
5550           op = TREE_OPERAND (op, 0);
5551           /* An extension: the outermost one can be stripped,
5552              but remember whether it is zero or sign extension.  */
5553           if (first)
5554             uns = TYPE_UNSIGNED (TREE_TYPE (op));
5555           /* Otherwise, if a sign extension has been stripped,
5556              only sign extensions can now be stripped;
5557              if a zero extension has been stripped, only zero-extensions.  */
5558           else if (uns != TYPE_UNSIGNED (TREE_TYPE (op)))
5559             break;
5560           first = 0;
5561         }
5562       else /* bitschange == 0 */
5563         {
5564           /* A change in nominal type can always be stripped, but we must
5565              preserve the unsignedness.  */
5566           if (first)
5567             uns = TYPE_UNSIGNED (TREE_TYPE (op));
5568           first = 0;
5569           op = TREE_OPERAND (op, 0);
5570           /* Keep trying to narrow, but don't assign op to win if it
5571              would turn an integral type into something else.  */
5572           if (INTEGRAL_TYPE_P (TREE_TYPE (op)) != integral_p)
5573             continue;
5574         }
5575
5576       win = op;
5577     }
5578
5579   if (TREE_CODE (op) == COMPONENT_REF
5580       /* Since type_for_size always gives an integer type.  */
5581       && TREE_CODE (TREE_TYPE (op)) != REAL_TYPE
5582       /* Ensure field is laid out already.  */
5583       && DECL_SIZE (TREE_OPERAND (op, 1)) != 0
5584       && host_integerp (DECL_SIZE (TREE_OPERAND (op, 1)), 1))
5585     {
5586       unsigned HOST_WIDE_INT innerprec
5587         = tree_low_cst (DECL_SIZE (TREE_OPERAND (op, 1)), 1);
5588       int unsignedp = (DECL_UNSIGNED (TREE_OPERAND (op, 1))
5589                        || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op, 1))));
5590       tree type = lang_hooks.types.type_for_size (innerprec, unsignedp);
5591
5592       /* We can get this structure field in a narrower type that fits it,
5593          but the resulting extension to its nominal type (a fullword type)
5594          must satisfy the same conditions as for other extensions.
5595
5596          Do this only for fields that are aligned (not bit-fields),
5597          because when bit-field insns will be used there is no
5598          advantage in doing this.  */
5599
5600       if (innerprec < TYPE_PRECISION (TREE_TYPE (op))
5601           && ! DECL_BIT_FIELD (TREE_OPERAND (op, 1))
5602           && (first || uns == DECL_UNSIGNED (TREE_OPERAND (op, 1)))
5603           && type != 0)
5604         {
5605           if (first)
5606             uns = DECL_UNSIGNED (TREE_OPERAND (op, 1));
5607           win = build3 (COMPONENT_REF, type, TREE_OPERAND (op, 0),
5608                         TREE_OPERAND (op, 1), NULL_TREE);
5609           TREE_SIDE_EFFECTS (win) = TREE_SIDE_EFFECTS (op);
5610           TREE_THIS_VOLATILE (win) = TREE_THIS_VOLATILE (op);
5611         }
5612     }
5613   *unsignedp_ptr = uns;
5614   return win;
5615 }
5616 \f
5617 /* Nonzero if integer constant C has a value that is permissible
5618    for type TYPE (an INTEGER_TYPE).  */
5619
5620 int
5621 int_fits_type_p (tree c, tree type)
5622 {
5623   tree type_low_bound = TYPE_MIN_VALUE (type);
5624   tree type_high_bound = TYPE_MAX_VALUE (type);
5625   bool ok_for_low_bound, ok_for_high_bound;
5626   tree tmp;
5627
5628   /* If at least one bound of the type is a constant integer, we can check
5629      ourselves and maybe make a decision. If no such decision is possible, but
5630      this type is a subtype, try checking against that.  Otherwise, use
5631      force_fit_type, which checks against the precision.
5632
5633      Compute the status for each possibly constant bound, and return if we see
5634      one does not match. Use ok_for_xxx_bound for this purpose, assigning -1
5635      for "unknown if constant fits", 0 for "constant known *not* to fit" and 1
5636      for "constant known to fit".  */
5637
5638   /* Check if C >= type_low_bound.  */
5639   if (type_low_bound && TREE_CODE (type_low_bound) == INTEGER_CST)
5640     {
5641       if (tree_int_cst_lt (c, type_low_bound))
5642         return 0;
5643       ok_for_low_bound = true;
5644     }
5645   else
5646     ok_for_low_bound = false;
5647
5648   /* Check if c <= type_high_bound.  */
5649   if (type_high_bound && TREE_CODE (type_high_bound) == INTEGER_CST)
5650     {
5651       if (tree_int_cst_lt (type_high_bound, c))
5652         return 0;
5653       ok_for_high_bound = true;
5654     }
5655   else
5656     ok_for_high_bound = false;
5657
5658   /* If the constant fits both bounds, the result is known.  */
5659   if (ok_for_low_bound && ok_for_high_bound)
5660     return 1;
5661
5662   /* Perform some generic filtering which may allow making a decision
5663      even if the bounds are not constant.  First, negative integers
5664      never fit in unsigned types, */
5665   if (TYPE_UNSIGNED (type) && tree_int_cst_sgn (c) < 0)
5666     return 0;
5667
5668   /* Second, narrower types always fit in wider ones.  */
5669   if (TYPE_PRECISION (type) > TYPE_PRECISION (TREE_TYPE (c)))
5670     return 1;
5671
5672   /* Third, unsigned integers with top bit set never fit signed types.  */
5673   if (! TYPE_UNSIGNED (type)
5674       && TYPE_UNSIGNED (TREE_TYPE (c))
5675       && tree_int_cst_msb (c))
5676     return 0;
5677
5678   /* If we haven't been able to decide at this point, there nothing more we
5679      can check ourselves here.  Look at the base type if we have one and it
5680      has the same precision.  */
5681   if (TREE_CODE (type) == INTEGER_TYPE
5682       && TREE_TYPE (type) != 0
5683       && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (type)))
5684     return int_fits_type_p (c, TREE_TYPE (type));
5685
5686   /* Or to force_fit_type, if nothing else.  */
5687   tmp = copy_node (c);
5688   TREE_TYPE (tmp) = type;
5689   tmp = force_fit_type (tmp, -1, false, false);
5690   return TREE_INT_CST_HIGH (tmp) == TREE_INT_CST_HIGH (c)
5691          && TREE_INT_CST_LOW (tmp) == TREE_INT_CST_LOW (c);
5692 }
5693
5694 /* Subprogram of following function.  Called by walk_tree.
5695
5696    Return *TP if it is an automatic variable or parameter of the
5697    function passed in as DATA.  */
5698
5699 static tree
5700 find_var_from_fn (tree *tp, int *walk_subtrees, void *data)
5701 {
5702   tree fn = (tree) data;
5703
5704   if (TYPE_P (*tp))
5705     *walk_subtrees = 0;
5706
5707   else if (DECL_P (*tp)
5708            && lang_hooks.tree_inlining.auto_var_in_fn_p (*tp, fn))
5709     return *tp;
5710
5711   return NULL_TREE;
5712 }
5713
5714 /* Returns true if T is, contains, or refers to a type with variable
5715    size.  For METHOD_TYPEs and FUNCTION_TYPEs we exclude the
5716    arguments, but not the return type.  If FN is nonzero, only return
5717    true if a modifier of the type or position of FN is a variable or
5718    parameter inside FN.
5719
5720    This concept is more general than that of C99 'variably modified types':
5721    in C99, a struct type is never variably modified because a VLA may not
5722    appear as a structure member.  However, in GNU C code like:
5723
5724      struct S { int i[f()]; };
5725
5726    is valid, and other languages may define similar constructs.  */
5727
5728 bool
5729 variably_modified_type_p (tree type, tree fn)
5730 {
5731   tree t;
5732
5733 /* Test if T is either variable (if FN is zero) or an expression containing
5734    a variable in FN.  */
5735 #define RETURN_TRUE_IF_VAR(T)                                           \
5736   do { tree _t = (T);                                                   \
5737     if (_t && _t != error_mark_node && TREE_CODE (_t) != INTEGER_CST    \
5738         && (!fn || walk_tree (&_t, find_var_from_fn, fn, NULL)))        \
5739       return true;  } while (0)
5740
5741   if (type == error_mark_node)
5742     return false;
5743
5744   /* If TYPE itself has variable size, it is variably modified.  */
5745   RETURN_TRUE_IF_VAR (TYPE_SIZE (type));
5746   RETURN_TRUE_IF_VAR (TYPE_SIZE_UNIT (type));
5747
5748   switch (TREE_CODE (type))
5749     {
5750     case POINTER_TYPE:
5751     case REFERENCE_TYPE:
5752     case VECTOR_TYPE:
5753       if (variably_modified_type_p (TREE_TYPE (type), fn))
5754         return true;
5755       break;
5756
5757     case FUNCTION_TYPE:
5758     case METHOD_TYPE:
5759       /* If TYPE is a function type, it is variably modified if the
5760          return type is variably modified.  */
5761       if (variably_modified_type_p (TREE_TYPE (type), fn))
5762           return true;
5763       break;
5764
5765     case INTEGER_TYPE:
5766     case REAL_TYPE:
5767     case ENUMERAL_TYPE:
5768     case BOOLEAN_TYPE:
5769       /* Scalar types are variably modified if their end points
5770          aren't constant.  */
5771       RETURN_TRUE_IF_VAR (TYPE_MIN_VALUE (type));
5772       RETURN_TRUE_IF_VAR (TYPE_MAX_VALUE (type));
5773       break;
5774
5775     case RECORD_TYPE:
5776     case UNION_TYPE:
5777     case QUAL_UNION_TYPE:
5778       /* We can't see if any of the fields are variably-modified by the
5779          definition we normally use, since that would produce infinite
5780          recursion via pointers.  */
5781       /* This is variably modified if some field's type is.  */
5782       for (t = TYPE_FIELDS (type); t; t = TREE_CHAIN (t))
5783         if (TREE_CODE (t) == FIELD_DECL)
5784           {
5785             RETURN_TRUE_IF_VAR (DECL_FIELD_OFFSET (t));
5786             RETURN_TRUE_IF_VAR (DECL_SIZE (t));
5787             RETURN_TRUE_IF_VAR (DECL_SIZE_UNIT (t));
5788
5789             if (TREE_CODE (type) == QUAL_UNION_TYPE)
5790               RETURN_TRUE_IF_VAR (DECL_QUALIFIER (t));
5791           }
5792         break;
5793
5794     case ARRAY_TYPE:
5795       /* Do not call ourselves to avoid infinite recursion.  This is
5796          variably modified if the element type is.  */
5797       RETURN_TRUE_IF_VAR (TYPE_SIZE (TREE_TYPE (type)));
5798       RETURN_TRUE_IF_VAR (TYPE_SIZE_UNIT (TREE_TYPE (type)));
5799       break;
5800
5801     default:
5802       break;
5803     }
5804
5805   /* The current language may have other cases to check, but in general,
5806      all other types are not variably modified.  */
5807   return lang_hooks.tree_inlining.var_mod_type_p (type, fn);
5808
5809 #undef RETURN_TRUE_IF_VAR
5810 }
5811
5812 /* Given a DECL or TYPE, return the scope in which it was declared, or
5813    NULL_TREE if there is no containing scope.  */
5814
5815 tree
5816 get_containing_scope (tree t)
5817 {
5818   return (TYPE_P (t) ? TYPE_CONTEXT (t) : DECL_CONTEXT (t));
5819 }
5820
5821 /* Return the innermost context enclosing DECL that is
5822    a FUNCTION_DECL, or zero if none.  */
5823
5824 tree
5825 decl_function_context (tree decl)
5826 {
5827   tree context;
5828
5829   if (TREE_CODE (decl) == ERROR_MARK)
5830     return 0;
5831
5832   /* C++ virtual functions use DECL_CONTEXT for the class of the vtable
5833      where we look up the function at runtime.  Such functions always take
5834      a first argument of type 'pointer to real context'.
5835
5836      C++ should really be fixed to use DECL_CONTEXT for the real context,
5837      and use something else for the "virtual context".  */
5838   else if (TREE_CODE (decl) == FUNCTION_DECL && DECL_VINDEX (decl))
5839     context
5840       = TYPE_MAIN_VARIANT
5841         (TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (decl)))));
5842   else
5843     context = DECL_CONTEXT (decl);
5844
5845   while (context && TREE_CODE (context) != FUNCTION_DECL)
5846     {
5847       if (TREE_CODE (context) == BLOCK)
5848         context = BLOCK_SUPERCONTEXT (context);
5849       else
5850         context = get_containing_scope (context);
5851     }
5852
5853   return context;
5854 }
5855
5856 /* Return the innermost context enclosing DECL that is
5857    a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE, or zero if none.
5858    TYPE_DECLs and FUNCTION_DECLs are transparent to this function.  */
5859
5860 tree
5861 decl_type_context (tree decl)
5862 {
5863   tree context = DECL_CONTEXT (decl);
5864
5865   while (context)
5866     switch (TREE_CODE (context))
5867       {
5868       case NAMESPACE_DECL:
5869       case TRANSLATION_UNIT_DECL:
5870         return NULL_TREE;
5871
5872       case RECORD_TYPE:
5873       case UNION_TYPE:
5874       case QUAL_UNION_TYPE:
5875         return context;
5876
5877       case TYPE_DECL:
5878       case FUNCTION_DECL:
5879         context = DECL_CONTEXT (context);
5880         break;
5881
5882       case BLOCK:
5883         context = BLOCK_SUPERCONTEXT (context);
5884         break;
5885
5886       default:
5887         gcc_unreachable ();
5888       }
5889
5890   return NULL_TREE;
5891 }
5892
5893 /* CALL is a CALL_EXPR.  Return the declaration for the function
5894    called, or NULL_TREE if the called function cannot be
5895    determined.  */
5896
5897 tree
5898 get_callee_fndecl (tree call)
5899 {
5900   tree addr;
5901
5902   if (call == error_mark_node)
5903     return call;
5904
5905   /* It's invalid to call this function with anything but a
5906      CALL_EXPR.  */
5907   gcc_assert (TREE_CODE (call) == CALL_EXPR);
5908
5909   /* The first operand to the CALL is the address of the function
5910      called.  */
5911   addr = TREE_OPERAND (call, 0);
5912
5913   STRIP_NOPS (addr);
5914
5915   /* If this is a readonly function pointer, extract its initial value.  */
5916   if (DECL_P (addr) && TREE_CODE (addr) != FUNCTION_DECL
5917       && TREE_READONLY (addr) && ! TREE_THIS_VOLATILE (addr)
5918       && DECL_INITIAL (addr))
5919     addr = DECL_INITIAL (addr);
5920
5921   /* If the address is just `&f' for some function `f', then we know
5922      that `f' is being called.  */
5923   if (TREE_CODE (addr) == ADDR_EXPR
5924       && TREE_CODE (TREE_OPERAND (addr, 0)) == FUNCTION_DECL)
5925     return TREE_OPERAND (addr, 0);
5926
5927   /* We couldn't figure out what was being called.  Maybe the front
5928      end has some idea.  */
5929   return lang_hooks.lang_get_callee_fndecl (call);
5930 }
5931
5932 /* Print debugging information about tree nodes generated during the compile,
5933    and any language-specific information.  */
5934
5935 void
5936 dump_tree_statistics (void)
5937 {
5938 #ifdef GATHER_STATISTICS
5939   int i;
5940   int total_nodes, total_bytes;
5941 #endif
5942
5943   fprintf (stderr, "\n??? tree nodes created\n\n");
5944 #ifdef GATHER_STATISTICS
5945   fprintf (stderr, "Kind                   Nodes      Bytes\n");
5946   fprintf (stderr, "---------------------------------------\n");
5947   total_nodes = total_bytes = 0;
5948   for (i = 0; i < (int) all_kinds; i++)
5949     {
5950       fprintf (stderr, "%-20s %7d %10d\n", tree_node_kind_names[i],
5951                tree_node_counts[i], tree_node_sizes[i]);
5952       total_nodes += tree_node_counts[i];
5953       total_bytes += tree_node_sizes[i];
5954     }
5955   fprintf (stderr, "---------------------------------------\n");
5956   fprintf (stderr, "%-20s %7d %10d\n", "Total", total_nodes, total_bytes);
5957   fprintf (stderr, "---------------------------------------\n");
5958   ssanames_print_statistics ();
5959   phinodes_print_statistics ();
5960 #else
5961   fprintf (stderr, "(No per-node statistics)\n");
5962 #endif
5963   print_type_hash_statistics ();
5964   print_debug_expr_statistics ();
5965   print_value_expr_statistics ();
5966   print_restrict_base_statistics ();
5967   lang_hooks.print_statistics ();
5968 }
5969 \f
5970 #define FILE_FUNCTION_FORMAT "_GLOBAL__%s_%s"
5971
5972 /* Generate a crc32 of a string.  */
5973
5974 unsigned
5975 crc32_string (unsigned chksum, const char *string)
5976 {
5977   do
5978     {
5979       unsigned value = *string << 24;
5980       unsigned ix;
5981
5982       for (ix = 8; ix--; value <<= 1)
5983         {
5984           unsigned feedback;
5985
5986           feedback = (value ^ chksum) & 0x80000000 ? 0x04c11db7 : 0;
5987           chksum <<= 1;
5988           chksum ^= feedback;
5989         }
5990     }
5991   while (*string++);
5992   return chksum;
5993 }
5994
5995 /* P is a string that will be used in a symbol.  Mask out any characters
5996    that are not valid in that context.  */
5997
5998 void
5999 clean_symbol_name (char *p)
6000 {
6001   for (; *p; p++)
6002     if (! (ISALNUM (*p)
6003 #ifndef NO_DOLLAR_IN_LABEL      /* this for `$'; unlikely, but... -- kr */
6004             || *p == '$'
6005 #endif
6006 #ifndef NO_DOT_IN_LABEL         /* this for `.'; unlikely, but...  */
6007             || *p == '.'
6008 #endif
6009            ))
6010       *p = '_';
6011 }
6012
6013 /* Generate a name for a function unique to this translation unit.
6014    TYPE is some string to identify the purpose of this function to the
6015    linker or collect2.  */
6016
6017 tree
6018 get_file_function_name_long (const char *type)
6019 {
6020   char *buf;
6021   const char *p;
6022   char *q;
6023
6024   if (first_global_object_name)
6025     {
6026       p = first_global_object_name;
6027
6028       /* For type 'F', the generated name must be unique not only to this
6029          translation unit but also to any given link.  Since global names
6030          can be overloaded, we concatenate the first global object name
6031          with a string derived from the file name of this object.  */
6032       if (!strcmp (type, "F"))
6033         {
6034           const char *file = main_input_filename;
6035
6036           if (! file)
6037             file = input_filename;
6038
6039           q = alloca (strlen (p) + 10);
6040           sprintf (q, "%s_%08X", p, crc32_string (0, file));
6041
6042           p = q;
6043         }
6044     }
6045   else
6046     {
6047       /* We don't have anything that we know to be unique to this translation
6048          unit, so use what we do have and throw in some randomness.  */
6049       unsigned len;
6050       const char *name = weak_global_object_name;
6051       const char *file = main_input_filename;
6052
6053       if (! name)
6054         name = "";
6055       if (! file)
6056         file = input_filename;
6057
6058       len = strlen (file);
6059       q = alloca (9 * 2 + len + 1);
6060       memcpy (q, file, len + 1);
6061       clean_symbol_name (q);
6062
6063       sprintf (q + len, "_%08X_%08X", crc32_string (0, name),
6064                crc32_string (0, flag_random_seed));
6065
6066       p = q;
6067     }
6068
6069   buf = alloca (sizeof (FILE_FUNCTION_FORMAT) + strlen (p) + strlen (type));
6070
6071   /* Set up the name of the file-level functions we may need.
6072      Use a global object (which is already required to be unique over
6073      the program) rather than the file name (which imposes extra
6074      constraints).  */
6075   sprintf (buf, FILE_FUNCTION_FORMAT, type, p);
6076
6077   return get_identifier (buf);
6078 }
6079
6080 /* If KIND=='I', return a suitable global initializer (constructor) name.
6081    If KIND=='D', return a suitable global clean-up (destructor) name.  */
6082
6083 tree
6084 get_file_function_name (int kind)
6085 {
6086   char p[2];
6087
6088   p[0] = kind;
6089   p[1] = 0;
6090
6091   return get_file_function_name_long (p);
6092 }
6093 \f
6094 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
6095
6096 /* Complain that the tree code of NODE does not match the expected 0
6097    terminated list of trailing codes. The trailing code list can be
6098    empty, for a more vague error message.  FILE, LINE, and FUNCTION
6099    are of the caller.  */
6100
6101 void
6102 tree_check_failed (const tree node, const char *file,
6103                    int line, const char *function, ...)
6104 {
6105   va_list args;
6106   char *buffer;
6107   unsigned length = 0;
6108   int code;
6109
6110   va_start (args, function);
6111   while ((code = va_arg (args, int)))
6112     length += 4 + strlen (tree_code_name[code]);
6113   va_end (args);
6114   if (length)
6115     {
6116       va_start (args, function);
6117       length += strlen ("expected ");
6118       buffer = alloca (length);
6119       length = 0;
6120       while ((code = va_arg (args, int)))
6121         {
6122           const char *prefix = length ? " or " : "expected ";
6123
6124           strcpy (buffer + length, prefix);
6125           length += strlen (prefix);
6126           strcpy (buffer + length, tree_code_name[code]);
6127           length += strlen (tree_code_name[code]);
6128         }
6129       va_end (args);
6130     }
6131   else
6132     buffer = (char *)"unexpected node";
6133
6134   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6135                   buffer, tree_code_name[TREE_CODE (node)],
6136                   function, trim_filename (file), line);
6137 }
6138
6139 /* Complain that the tree code of NODE does match the expected 0
6140    terminated list of trailing codes. FILE, LINE, and FUNCTION are of
6141    the caller.  */
6142
6143 void
6144 tree_not_check_failed (const tree node, const char *file,
6145                        int line, const char *function, ...)
6146 {
6147   va_list args;
6148   char *buffer;
6149   unsigned length = 0;
6150   int code;
6151
6152   va_start (args, function);
6153   while ((code = va_arg (args, int)))
6154     length += 4 + strlen (tree_code_name[code]);
6155   va_end (args);
6156   va_start (args, function);
6157   buffer = alloca (length);
6158   length = 0;
6159   while ((code = va_arg (args, int)))
6160     {
6161       if (length)
6162         {
6163           strcpy (buffer + length, " or ");
6164           length += 4;
6165         }
6166       strcpy (buffer + length, tree_code_name[code]);
6167       length += strlen (tree_code_name[code]);
6168     }
6169   va_end (args);
6170
6171   internal_error ("tree check: expected none of %s, have %s in %s, at %s:%d",
6172                   buffer, tree_code_name[TREE_CODE (node)],
6173                   function, trim_filename (file), line);
6174 }
6175
6176 /* Similar to tree_check_failed, except that we check for a class of tree
6177    code, given in CL.  */
6178
6179 void
6180 tree_class_check_failed (const tree node, const enum tree_code_class cl,
6181                          const char *file, int line, const char *function)
6182 {
6183   internal_error
6184     ("tree check: expected class %qs, have %qs (%s) in %s, at %s:%d",
6185      TREE_CODE_CLASS_STRING (cl),
6186      TREE_CODE_CLASS_STRING (TREE_CODE_CLASS (TREE_CODE (node))),
6187      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6188 }
6189
6190 /* Similar to tree_check_failed, except that instead of specifying a
6191    dozen codes, use the knowledge that they're all sequential.  */
6192
6193 void
6194 tree_range_check_failed (const tree node, const char *file, int line,
6195                          const char *function, enum tree_code c1,
6196                          enum tree_code c2)
6197 {
6198   char *buffer;
6199   unsigned length = 0;
6200   enum tree_code c;
6201
6202   for (c = c1; c <= c2; ++c)
6203     length += 4 + strlen (tree_code_name[c]);
6204
6205   length += strlen ("expected ");
6206   buffer = alloca (length);
6207   length = 0;
6208
6209   for (c = c1; c <= c2; ++c)
6210     {
6211       const char *prefix = length ? " or " : "expected ";
6212
6213       strcpy (buffer + length, prefix);
6214       length += strlen (prefix);
6215       strcpy (buffer + length, tree_code_name[c]);
6216       length += strlen (tree_code_name[c]);
6217     }
6218
6219   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6220                   buffer, tree_code_name[TREE_CODE (node)],
6221                   function, trim_filename (file), line);
6222 }
6223
6224
6225 /* Similar to tree_check_failed, except that we check that a tree does
6226    not have the specified code, given in CL.  */
6227
6228 void
6229 tree_not_class_check_failed (const tree node, const enum tree_code_class cl,
6230                              const char *file, int line, const char *function)
6231 {
6232   internal_error
6233     ("tree check: did not expect class %qs, have %qs (%s) in %s, at %s:%d",
6234      TREE_CODE_CLASS_STRING (cl),
6235      TREE_CODE_CLASS_STRING (TREE_CODE_CLASS (TREE_CODE (node))),
6236      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6237 }
6238
6239
6240 /* Similar to tree_check_failed but applied to OMP_CLAUSE codes.  */
6241
6242 void
6243 omp_clause_check_failed (const tree node, const char *file, int line,
6244                          const char *function, enum omp_clause_code code)
6245 {
6246   internal_error ("tree check: expected omp_clause %s, have %s in %s, at %s:%d",
6247                   omp_clause_code_name[code], tree_code_name[TREE_CODE (node)],
6248                   function, trim_filename (file), line);
6249 }
6250
6251
6252 /* Similar to tree_range_check_failed but applied to OMP_CLAUSE codes.  */
6253
6254 void
6255 omp_clause_range_check_failed (const tree node, const char *file, int line,
6256                                const char *function, enum omp_clause_code c1,
6257                                enum omp_clause_code c2)
6258 {
6259   char *buffer;
6260   unsigned length = 0;
6261   enum omp_clause_code c;
6262
6263   for (c = c1; c <= c2; ++c)
6264     length += 4 + strlen (omp_clause_code_name[c]);
6265
6266   length += strlen ("expected ");
6267   buffer = alloca (length);
6268   length = 0;
6269
6270   for (c = c1; c <= c2; ++c)
6271     {
6272       const char *prefix = length ? " or " : "expected ";
6273
6274       strcpy (buffer + length, prefix);
6275       length += strlen (prefix);
6276       strcpy (buffer + length, omp_clause_code_name[c]);
6277       length += strlen (omp_clause_code_name[c]);
6278     }
6279
6280   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6281                   buffer, omp_clause_code_name[TREE_CODE (node)],
6282                   function, trim_filename (file), line);
6283 }
6284
6285
6286 #undef DEFTREESTRUCT
6287 #define DEFTREESTRUCT(VAL, NAME) NAME,
6288
6289 static const char *ts_enum_names[] = {
6290 #include "treestruct.def"
6291 };
6292 #undef DEFTREESTRUCT
6293
6294 #define TS_ENUM_NAME(EN) (ts_enum_names[(EN)])
6295
6296 /* Similar to tree_class_check_failed, except that we check for
6297    whether CODE contains the tree structure identified by EN.  */
6298
6299 void
6300 tree_contains_struct_check_failed (const tree node,
6301                                    const enum tree_node_structure_enum en,
6302                                    const char *file, int line,
6303                                    const char *function)
6304 {
6305   internal_error
6306     ("tree check: expected tree that contains %qs structure, have %qs  in %s, at %s:%d",
6307      TS_ENUM_NAME(en),
6308      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6309 }
6310
6311
6312 /* Similar to above, except that the check is for the bounds of a TREE_VEC's
6313    (dynamically sized) vector.  */
6314
6315 void
6316 tree_vec_elt_check_failed (int idx, int len, const char *file, int line,
6317                            const char *function)
6318 {
6319   internal_error
6320     ("tree check: accessed elt %d of tree_vec with %d elts in %s, at %s:%d",
6321      idx + 1, len, function, trim_filename (file), line);
6322 }
6323
6324 /* Similar to above, except that the check is for the bounds of a PHI_NODE's
6325    (dynamically sized) vector.  */
6326
6327 void
6328 phi_node_elt_check_failed (int idx, int len, const char *file, int line,
6329                             const char *function)
6330 {
6331   internal_error
6332     ("tree check: accessed elt %d of phi_node with %d elts in %s, at %s:%d",
6333      idx + 1, len, function, trim_filename (file), line);
6334 }
6335
6336 /* Similar to above, except that the check is for the bounds of the operand
6337    vector of an expression node.  */
6338
6339 void
6340 tree_operand_check_failed (int idx, enum tree_code code, const char *file,
6341                            int line, const char *function)
6342 {
6343   internal_error
6344     ("tree check: accessed operand %d of %s with %d operands in %s, at %s:%d",
6345      idx + 1, tree_code_name[code], TREE_CODE_LENGTH (code),
6346      function, trim_filename (file), line);
6347 }
6348
6349 /* Similar to above, except that the check is for the number of
6350    operands of an OMP_CLAUSE node.  */
6351
6352 void
6353 omp_clause_operand_check_failed (int idx, tree t, const char *file,
6354                                  int line, const char *function)
6355 {
6356   internal_error
6357     ("tree check: accessed operand %d of omp_clause %s with %d operands "
6358      "in %s, at %s:%d", idx + 1, omp_clause_code_name[OMP_CLAUSE_CODE (t)],
6359      omp_clause_num_ops [OMP_CLAUSE_CODE (t)], function,
6360      trim_filename (file), line);
6361 }
6362 #endif /* ENABLE_TREE_CHECKING */
6363 \f
6364 /* Create a new vector type node holding SUBPARTS units of type INNERTYPE,
6365    and mapped to the machine mode MODE.  Initialize its fields and build
6366    the information necessary for debugging output.  */
6367
6368 static tree
6369 make_vector_type (tree innertype, int nunits, enum machine_mode mode)
6370 {
6371   tree t = make_node (VECTOR_TYPE);
6372
6373   TREE_TYPE (t) = TYPE_MAIN_VARIANT (innertype);
6374   SET_TYPE_VECTOR_SUBPARTS (t, nunits);
6375   TYPE_MODE (t) = mode;
6376   TYPE_READONLY (t) = TYPE_READONLY (innertype);
6377   TYPE_VOLATILE (t) = TYPE_VOLATILE (innertype);
6378
6379   layout_type (t);
6380
6381   {
6382     tree index = build_int_cst (NULL_TREE, nunits - 1);
6383     tree array = build_array_type (innertype, build_index_type (index));
6384     tree rt = make_node (RECORD_TYPE);
6385
6386     TYPE_FIELDS (rt) = build_decl (FIELD_DECL, get_identifier ("f"), array);
6387     DECL_CONTEXT (TYPE_FIELDS (rt)) = rt;
6388     layout_type (rt);
6389     TYPE_DEBUG_REPRESENTATION_TYPE (t) = rt;
6390     /* In dwarfout.c, type lookup uses TYPE_UID numbers.  We want to output
6391        the representation type, and we want to find that die when looking up
6392        the vector type.  This is most easily achieved by making the TYPE_UID
6393        numbers equal.  */
6394     TYPE_UID (rt) = TYPE_UID (t);
6395   }
6396
6397   /* Build our main variant, based on the main variant of the inner type.  */
6398   if (TYPE_MAIN_VARIANT (innertype) != innertype)
6399     {
6400       tree innertype_main_variant = TYPE_MAIN_VARIANT (innertype);
6401       unsigned int hash = TYPE_HASH (innertype_main_variant);
6402       TYPE_MAIN_VARIANT (t)
6403         = type_hash_canon (hash, make_vector_type (innertype_main_variant,
6404                                                    nunits, mode));
6405     }
6406
6407   return t;
6408 }
6409
6410 static tree
6411 make_or_reuse_type (unsigned size, int unsignedp)
6412 {
6413   if (size == INT_TYPE_SIZE)
6414     return unsignedp ? unsigned_type_node : integer_type_node;
6415   if (size == CHAR_TYPE_SIZE)
6416     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
6417   if (size == SHORT_TYPE_SIZE)
6418     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
6419   if (size == LONG_TYPE_SIZE)
6420     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
6421   if (size == LONG_LONG_TYPE_SIZE)
6422     return (unsignedp ? long_long_unsigned_type_node
6423             : long_long_integer_type_node);
6424
6425   if (unsignedp)
6426     return make_unsigned_type (size);
6427   else
6428     return make_signed_type (size);
6429 }
6430
6431 /* Create nodes for all integer types (and error_mark_node) using the sizes
6432    of C datatypes.  The caller should call set_sizetype soon after calling
6433    this function to select one of the types as sizetype.  */
6434
6435 void
6436 build_common_tree_nodes (bool signed_char, bool signed_sizetype)
6437 {
6438   error_mark_node = make_node (ERROR_MARK);
6439   TREE_TYPE (error_mark_node) = error_mark_node;
6440
6441   initialize_sizetypes (signed_sizetype);
6442
6443   /* Define both `signed char' and `unsigned char'.  */
6444   signed_char_type_node = make_signed_type (CHAR_TYPE_SIZE);
6445   TYPE_STRING_FLAG (signed_char_type_node) = 1;
6446   unsigned_char_type_node = make_unsigned_type (CHAR_TYPE_SIZE);
6447   TYPE_STRING_FLAG (unsigned_char_type_node) = 1;
6448
6449   /* Define `char', which is like either `signed char' or `unsigned char'
6450      but not the same as either.  */
6451   char_type_node
6452     = (signed_char
6453        ? make_signed_type (CHAR_TYPE_SIZE)
6454        : make_unsigned_type (CHAR_TYPE_SIZE));
6455   TYPE_STRING_FLAG (char_type_node) = 1;
6456
6457   short_integer_type_node = make_signed_type (SHORT_TYPE_SIZE);
6458   short_unsigned_type_node = make_unsigned_type (SHORT_TYPE_SIZE);
6459   integer_type_node = make_signed_type (INT_TYPE_SIZE);
6460   unsigned_type_node = make_unsigned_type (INT_TYPE_SIZE);
6461   long_integer_type_node = make_signed_type (LONG_TYPE_SIZE);
6462   long_unsigned_type_node = make_unsigned_type (LONG_TYPE_SIZE);
6463   long_long_integer_type_node = make_signed_type (LONG_LONG_TYPE_SIZE);
6464   long_long_unsigned_type_node = make_unsigned_type (LONG_LONG_TYPE_SIZE);
6465
6466   /* Define a boolean type.  This type only represents boolean values but
6467      may be larger than char depending on the value of BOOL_TYPE_SIZE.
6468      Front ends which want to override this size (i.e. Java) can redefine
6469      boolean_type_node before calling build_common_tree_nodes_2.  */
6470   boolean_type_node = make_unsigned_type (BOOL_TYPE_SIZE);
6471   TREE_SET_CODE (boolean_type_node, BOOLEAN_TYPE);
6472   TYPE_MAX_VALUE (boolean_type_node) = build_int_cst (boolean_type_node, 1);
6473   TYPE_PRECISION (boolean_type_node) = 1;
6474
6475   /* Fill in the rest of the sized types.  Reuse existing type nodes
6476      when possible.  */
6477   intQI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (QImode), 0);
6478   intHI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (HImode), 0);
6479   intSI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (SImode), 0);
6480   intDI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (DImode), 0);
6481   intTI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (TImode), 0);
6482
6483   unsigned_intQI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (QImode), 1);
6484   unsigned_intHI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (HImode), 1);
6485   unsigned_intSI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (SImode), 1);
6486   unsigned_intDI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (DImode), 1);
6487   unsigned_intTI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (TImode), 1);
6488
6489   access_public_node = get_identifier ("public");
6490   access_protected_node = get_identifier ("protected");
6491   access_private_node = get_identifier ("private");
6492 }
6493
6494 /* Call this function after calling build_common_tree_nodes and set_sizetype.
6495    It will create several other common tree nodes.  */
6496
6497 void
6498 build_common_tree_nodes_2 (int short_double)
6499 {
6500   /* Define these next since types below may used them.  */
6501   integer_zero_node = build_int_cst (NULL_TREE, 0);
6502   integer_one_node = build_int_cst (NULL_TREE, 1);
6503   integer_minus_one_node = build_int_cst (NULL_TREE, -1);
6504
6505   size_zero_node = size_int (0);
6506   size_one_node = size_int (1);
6507   bitsize_zero_node = bitsize_int (0);
6508   bitsize_one_node = bitsize_int (1);
6509   bitsize_unit_node = bitsize_int (BITS_PER_UNIT);
6510
6511   boolean_false_node = TYPE_MIN_VALUE (boolean_type_node);
6512   boolean_true_node = TYPE_MAX_VALUE (boolean_type_node);
6513
6514   void_type_node = make_node (VOID_TYPE);
6515   layout_type (void_type_node);
6516
6517   /* We are not going to have real types in C with less than byte alignment,
6518      so we might as well not have any types that claim to have it.  */
6519   TYPE_ALIGN (void_type_node) = BITS_PER_UNIT;
6520   TYPE_USER_ALIGN (void_type_node) = 0;
6521
6522   null_pointer_node = build_int_cst (build_pointer_type (void_type_node), 0);
6523   layout_type (TREE_TYPE (null_pointer_node));
6524
6525   ptr_type_node = build_pointer_type (void_type_node);
6526   const_ptr_type_node
6527     = build_pointer_type (build_type_variant (void_type_node, 1, 0));
6528   fileptr_type_node = ptr_type_node;
6529
6530   float_type_node = make_node (REAL_TYPE);
6531   TYPE_PRECISION (float_type_node) = FLOAT_TYPE_SIZE;
6532   layout_type (float_type_node);
6533
6534   double_type_node = make_node (REAL_TYPE);
6535   if (short_double)
6536     TYPE_PRECISION (double_type_node) = FLOAT_TYPE_SIZE;
6537   else
6538     TYPE_PRECISION (double_type_node) = DOUBLE_TYPE_SIZE;
6539   layout_type (double_type_node);
6540
6541   long_double_type_node = make_node (REAL_TYPE);
6542   TYPE_PRECISION (long_double_type_node) = LONG_DOUBLE_TYPE_SIZE;
6543   layout_type (long_double_type_node);
6544
6545   float_ptr_type_node = build_pointer_type (float_type_node);
6546   double_ptr_type_node = build_pointer_type (double_type_node);
6547   long_double_ptr_type_node = build_pointer_type (long_double_type_node);
6548   integer_ptr_type_node = build_pointer_type (integer_type_node);
6549
6550   /* Decimal float types. */
6551   dfloat32_type_node = make_node (REAL_TYPE);
6552   TYPE_PRECISION (dfloat32_type_node) = DECIMAL32_TYPE_SIZE;
6553   layout_type (dfloat32_type_node);
6554   TYPE_MODE (dfloat32_type_node) = SDmode;
6555   dfloat32_ptr_type_node = build_pointer_type (dfloat32_type_node);
6556
6557   dfloat64_type_node = make_node (REAL_TYPE);
6558   TYPE_PRECISION (dfloat64_type_node) = DECIMAL64_TYPE_SIZE;
6559   layout_type (dfloat64_type_node);
6560   TYPE_MODE (dfloat64_type_node) = DDmode;
6561   dfloat64_ptr_type_node = build_pointer_type (dfloat64_type_node);
6562
6563   dfloat128_type_node = make_node (REAL_TYPE);
6564   TYPE_PRECISION (dfloat128_type_node) = DECIMAL128_TYPE_SIZE;
6565   layout_type (dfloat128_type_node);
6566   TYPE_MODE (dfloat128_type_node) = TDmode;
6567   dfloat128_ptr_type_node = build_pointer_type (dfloat128_type_node);
6568
6569   complex_integer_type_node = make_node (COMPLEX_TYPE);
6570   TREE_TYPE (complex_integer_type_node) = integer_type_node;
6571   layout_type (complex_integer_type_node);
6572
6573   complex_float_type_node = make_node (COMPLEX_TYPE);
6574   TREE_TYPE (complex_float_type_node) = float_type_node;
6575   layout_type (complex_float_type_node);
6576
6577   complex_double_type_node = make_node (COMPLEX_TYPE);
6578   TREE_TYPE (complex_double_type_node) = double_type_node;
6579   layout_type (complex_double_type_node);
6580
6581   complex_long_double_type_node = make_node (COMPLEX_TYPE);
6582   TREE_TYPE (complex_long_double_type_node) = long_double_type_node;
6583   layout_type (complex_long_double_type_node);
6584
6585   {
6586     tree t = targetm.build_builtin_va_list ();
6587
6588     /* Many back-ends define record types without setting TYPE_NAME.
6589        If we copied the record type here, we'd keep the original
6590        record type without a name.  This breaks name mangling.  So,
6591        don't copy record types and let c_common_nodes_and_builtins()
6592        declare the type to be __builtin_va_list.  */
6593     if (TREE_CODE (t) != RECORD_TYPE)
6594       t = build_variant_type_copy (t);
6595
6596     va_list_type_node = t;
6597   }
6598 }
6599
6600 /* A subroutine of build_common_builtin_nodes.  Define a builtin function.  */
6601
6602 static void
6603 local_define_builtin (const char *name, tree type, enum built_in_function code,
6604                       const char *library_name, int ecf_flags)
6605 {
6606   tree decl;
6607
6608   decl = lang_hooks.builtin_function (name, type, code, BUILT_IN_NORMAL,
6609                                       library_name, NULL_TREE);
6610   if (ecf_flags & ECF_CONST)
6611     TREE_READONLY (decl) = 1;
6612   if (ecf_flags & ECF_PURE)
6613     DECL_IS_PURE (decl) = 1;
6614   if (ecf_flags & ECF_NORETURN)
6615     TREE_THIS_VOLATILE (decl) = 1;
6616   if (ecf_flags & ECF_NOTHROW)
6617     TREE_NOTHROW (decl) = 1;
6618   if (ecf_flags & ECF_MALLOC)
6619     DECL_IS_MALLOC (decl) = 1;
6620
6621   built_in_decls[code] = decl;
6622   implicit_built_in_decls[code] = decl;
6623 }
6624
6625 /* Call this function after instantiating all builtins that the language
6626    front end cares about.  This will build the rest of the builtins that
6627    are relied upon by the tree optimizers and the middle-end.  */
6628
6629 void
6630 build_common_builtin_nodes (void)
6631 {
6632   tree tmp, ftype;
6633
6634   if (built_in_decls[BUILT_IN_MEMCPY] == NULL
6635       || built_in_decls[BUILT_IN_MEMMOVE] == NULL)
6636     {
6637       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6638       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6639       tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6640       ftype = build_function_type (ptr_type_node, tmp);
6641
6642       if (built_in_decls[BUILT_IN_MEMCPY] == NULL)
6643         local_define_builtin ("__builtin_memcpy", ftype, BUILT_IN_MEMCPY,
6644                               "memcpy", ECF_NOTHROW);
6645       if (built_in_decls[BUILT_IN_MEMMOVE] == NULL)
6646         local_define_builtin ("__builtin_memmove", ftype, BUILT_IN_MEMMOVE,
6647                               "memmove", ECF_NOTHROW);
6648     }
6649
6650   if (built_in_decls[BUILT_IN_MEMCMP] == NULL)
6651     {
6652       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6653       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6654       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6655       ftype = build_function_type (integer_type_node, tmp);
6656       local_define_builtin ("__builtin_memcmp", ftype, BUILT_IN_MEMCMP,
6657                             "memcmp", ECF_PURE | ECF_NOTHROW);
6658     }
6659
6660   if (built_in_decls[BUILT_IN_MEMSET] == NULL)
6661     {
6662       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6663       tmp = tree_cons (NULL_TREE, integer_type_node, tmp);
6664       tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6665       ftype = build_function_type (ptr_type_node, tmp);
6666       local_define_builtin ("__builtin_memset", ftype, BUILT_IN_MEMSET,
6667                             "memset", ECF_NOTHROW);
6668     }
6669
6670   if (built_in_decls[BUILT_IN_ALLOCA] == NULL)
6671     {
6672       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6673       ftype = build_function_type (ptr_type_node, tmp);
6674       local_define_builtin ("__builtin_alloca", ftype, BUILT_IN_ALLOCA,
6675                             "alloca", ECF_NOTHROW | ECF_MALLOC);
6676     }
6677
6678   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6679   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6680   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6681   ftype = build_function_type (void_type_node, tmp);
6682   local_define_builtin ("__builtin_init_trampoline", ftype,
6683                         BUILT_IN_INIT_TRAMPOLINE,
6684                         "__builtin_init_trampoline", ECF_NOTHROW);
6685
6686   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6687   ftype = build_function_type (ptr_type_node, tmp);
6688   local_define_builtin ("__builtin_adjust_trampoline", ftype,
6689                         BUILT_IN_ADJUST_TRAMPOLINE,
6690                         "__builtin_adjust_trampoline",
6691                         ECF_CONST | ECF_NOTHROW);
6692
6693   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6694   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6695   ftype = build_function_type (void_type_node, tmp);
6696   local_define_builtin ("__builtin_nonlocal_goto", ftype,
6697                         BUILT_IN_NONLOCAL_GOTO,
6698                         "__builtin_nonlocal_goto",
6699                         ECF_NORETURN | ECF_NOTHROW);
6700
6701   ftype = build_function_type (ptr_type_node, void_list_node);
6702   local_define_builtin ("__builtin_stack_save", ftype, BUILT_IN_STACK_SAVE,
6703                         "__builtin_stack_save", ECF_NOTHROW);
6704
6705   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6706   ftype = build_function_type (void_type_node, tmp);
6707   local_define_builtin ("__builtin_stack_restore", ftype,
6708                         BUILT_IN_STACK_RESTORE,
6709                         "__builtin_stack_restore", ECF_NOTHROW);
6710
6711   ftype = build_function_type (void_type_node, void_list_node);
6712   local_define_builtin ("__builtin_profile_func_enter", ftype,
6713                         BUILT_IN_PROFILE_FUNC_ENTER, "profile_func_enter", 0);
6714   local_define_builtin ("__builtin_profile_func_exit", ftype,
6715                         BUILT_IN_PROFILE_FUNC_EXIT, "profile_func_exit", 0);
6716
6717   /* Complex multiplication and division.  These are handled as builtins
6718      rather than optabs because emit_library_call_value doesn't support
6719      complex.  Further, we can do slightly better with folding these
6720      beasties if the real and complex parts of the arguments are separate.  */
6721   {
6722     enum machine_mode mode;
6723
6724     for (mode = MIN_MODE_COMPLEX_FLOAT; mode <= MAX_MODE_COMPLEX_FLOAT; ++mode)
6725       {
6726         char mode_name_buf[4], *q;
6727         const char *p;
6728         enum built_in_function mcode, dcode;
6729         tree type, inner_type;
6730
6731         type = lang_hooks.types.type_for_mode (mode, 0);
6732         if (type == NULL)
6733           continue;
6734         inner_type = TREE_TYPE (type);
6735
6736         tmp = tree_cons (NULL_TREE, inner_type, void_list_node);
6737         tmp = tree_cons (NULL_TREE, inner_type, tmp);
6738         tmp = tree_cons (NULL_TREE, inner_type, tmp);
6739         tmp = tree_cons (NULL_TREE, inner_type, tmp);
6740         ftype = build_function_type (type, tmp);
6741
6742         mcode = BUILT_IN_COMPLEX_MUL_MIN + mode - MIN_MODE_COMPLEX_FLOAT;
6743         dcode = BUILT_IN_COMPLEX_DIV_MIN + mode - MIN_MODE_COMPLEX_FLOAT;
6744
6745         for (p = GET_MODE_NAME (mode), q = mode_name_buf; *p; p++, q++)
6746           *q = TOLOWER (*p);
6747         *q = '\0';
6748
6749         built_in_names[mcode] = concat ("__mul", mode_name_buf, "3", NULL);
6750         local_define_builtin (built_in_names[mcode], ftype, mcode,
6751                               built_in_names[mcode], ECF_CONST | ECF_NOTHROW);
6752
6753         built_in_names[dcode] = concat ("__div", mode_name_buf, "3", NULL);
6754         local_define_builtin (built_in_names[dcode], ftype, dcode,
6755                               built_in_names[dcode], ECF_CONST | ECF_NOTHROW);
6756       }
6757   }
6758 }
6759
6760 /* HACK.  GROSS.  This is absolutely disgusting.  I wish there was a
6761    better way.
6762
6763    If we requested a pointer to a vector, build up the pointers that
6764    we stripped off while looking for the inner type.  Similarly for
6765    return values from functions.
6766
6767    The argument TYPE is the top of the chain, and BOTTOM is the
6768    new type which we will point to.  */
6769
6770 tree
6771 reconstruct_complex_type (tree type, tree bottom)
6772 {
6773   tree inner, outer;
6774
6775   if (POINTER_TYPE_P (type))
6776     {
6777       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6778       outer = build_pointer_type (inner);
6779     }
6780   else if (TREE_CODE (type) == ARRAY_TYPE)
6781     {
6782       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6783       outer = build_array_type (inner, TYPE_DOMAIN (type));
6784     }
6785   else if (TREE_CODE (type) == FUNCTION_TYPE)
6786     {
6787       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6788       outer = build_function_type (inner, TYPE_ARG_TYPES (type));
6789     }
6790   else if (TREE_CODE (type) == METHOD_TYPE)
6791     {
6792       tree argtypes;
6793       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6794       /* The build_method_type_directly() routine prepends 'this' to argument list,
6795          so we must compensate by getting rid of it.  */
6796       argtypes = TYPE_ARG_TYPES (type);
6797       outer = build_method_type_directly (TYPE_METHOD_BASETYPE (type),
6798                                           inner,
6799                                           TYPE_ARG_TYPES (type));
6800       TYPE_ARG_TYPES (outer) = argtypes;
6801     }
6802   else
6803     return bottom;
6804
6805   TYPE_READONLY (outer) = TYPE_READONLY (type);
6806   TYPE_VOLATILE (outer) = TYPE_VOLATILE (type);
6807
6808   return outer;
6809 }
6810
6811 /* Returns a vector tree node given a mode (integer, vector, or BLKmode) and
6812    the inner type.  */
6813 tree
6814 build_vector_type_for_mode (tree innertype, enum machine_mode mode)
6815 {
6816   int nunits;
6817
6818   switch (GET_MODE_CLASS (mode))
6819     {
6820     case MODE_VECTOR_INT:
6821     case MODE_VECTOR_FLOAT:
6822       nunits = GET_MODE_NUNITS (mode);
6823       break;
6824
6825     case MODE_INT:
6826       /* Check that there are no leftover bits.  */
6827       gcc_assert (GET_MODE_BITSIZE (mode)
6828                   % TREE_INT_CST_LOW (TYPE_SIZE (innertype)) == 0);
6829
6830       nunits = GET_MODE_BITSIZE (mode)
6831                / TREE_INT_CST_LOW (TYPE_SIZE (innertype));
6832       break;
6833
6834     default:
6835       gcc_unreachable ();
6836     }
6837
6838   return make_vector_type (innertype, nunits, mode);
6839 }
6840
6841 /* Similarly, but takes the inner type and number of units, which must be
6842    a power of two.  */
6843
6844 tree
6845 build_vector_type (tree innertype, int nunits)
6846 {
6847   return make_vector_type (innertype, nunits, VOIDmode);
6848 }
6849
6850 /* Build RESX_EXPR with given REGION_NUMBER.  */
6851 tree
6852 build_resx (int region_number)
6853 {
6854   tree t;
6855   t = build1 (RESX_EXPR, void_type_node,
6856               build_int_cst (NULL_TREE, region_number));
6857   return t;
6858 }
6859
6860 /* Given an initializer INIT, return TRUE if INIT is zero or some
6861    aggregate of zeros.  Otherwise return FALSE.  */
6862 bool
6863 initializer_zerop (tree init)
6864 {
6865   tree elt;
6866
6867   STRIP_NOPS (init);
6868
6869   switch (TREE_CODE (init))
6870     {
6871     case INTEGER_CST:
6872       return integer_zerop (init);
6873
6874     case REAL_CST:
6875       /* ??? Note that this is not correct for C4X float formats.  There,
6876          a bit pattern of all zeros is 1.0; 0.0 is encoded with the most
6877          negative exponent.  */
6878       return real_zerop (init)
6879         && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (init));
6880
6881     case COMPLEX_CST:
6882       return integer_zerop (init)
6883         || (real_zerop (init)
6884             && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_REALPART (init)))
6885             && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_IMAGPART (init))));
6886
6887     case VECTOR_CST:
6888       for (elt = TREE_VECTOR_CST_ELTS (init); elt; elt = TREE_CHAIN (elt))
6889         if (!initializer_zerop (TREE_VALUE (elt)))
6890           return false;
6891       return true;
6892
6893     case CONSTRUCTOR:
6894       {
6895         unsigned HOST_WIDE_INT idx;
6896
6897         FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), idx, elt)
6898           if (!initializer_zerop (elt))
6899             return false;
6900         return true;
6901       }
6902
6903     default:
6904       return false;
6905     }
6906 }
6907
6908 /* Build an empty statement.  */
6909
6910 tree
6911 build_empty_stmt (void)
6912 {
6913   return build1 (NOP_EXPR, void_type_node, size_zero_node);
6914 }
6915
6916
6917 /* Build an OpenMP clause with code CODE.  */
6918
6919 tree
6920 build_omp_clause (enum omp_clause_code code)
6921 {
6922   tree t;
6923   int size, length;
6924
6925   length = omp_clause_num_ops[code];
6926   size = (sizeof (struct tree_omp_clause) + (length - 1) * sizeof (tree));
6927
6928   t = ggc_alloc (size);
6929   memset (t, 0, size);
6930   TREE_SET_CODE (t, OMP_CLAUSE);
6931   OMP_CLAUSE_SET_CODE (t, code);
6932
6933 #ifdef GATHER_STATISTICS
6934   tree_node_counts[(int) omp_clause_kind]++;
6935   tree_node_sizes[(int) omp_clause_kind] += size;
6936 #endif
6937
6938   return t;
6939 }
6940
6941
6942 /* Returns true if it is possible to prove that the index of
6943    an array access REF (an ARRAY_REF expression) falls into the
6944    array bounds.  */
6945
6946 bool
6947 in_array_bounds_p (tree ref)
6948 {
6949   tree idx = TREE_OPERAND (ref, 1);
6950   tree min, max;
6951
6952   if (TREE_CODE (idx) != INTEGER_CST)
6953     return false;
6954
6955   min = array_ref_low_bound (ref);
6956   max = array_ref_up_bound (ref);
6957   if (!min
6958       || !max
6959       || TREE_CODE (min) != INTEGER_CST
6960       || TREE_CODE (max) != INTEGER_CST)
6961     return false;
6962
6963   if (tree_int_cst_lt (idx, min)
6964       || tree_int_cst_lt (max, idx))
6965     return false;
6966
6967   return true;
6968 }
6969
6970 /* Returns true if it is possible to prove that the range of
6971    an array access REF (an ARRAY_RANGE_REF expression) falls
6972    into the array bounds.  */
6973
6974 bool
6975 range_in_array_bounds_p (tree ref)
6976 {
6977   tree domain_type = TYPE_DOMAIN (TREE_TYPE (ref));
6978   tree range_min, range_max, min, max;
6979
6980   range_min = TYPE_MIN_VALUE (domain_type);
6981   range_max = TYPE_MAX_VALUE (domain_type);
6982   if (!range_min
6983       || !range_max
6984       || TREE_CODE (range_min) != INTEGER_CST
6985       || TREE_CODE (range_max) != INTEGER_CST)
6986     return false;
6987
6988   min = array_ref_low_bound (ref);
6989   max = array_ref_up_bound (ref);
6990   if (!min
6991       || !max
6992       || TREE_CODE (min) != INTEGER_CST
6993       || TREE_CODE (max) != INTEGER_CST)
6994     return false;
6995
6996   if (tree_int_cst_lt (range_min, min)
6997       || tree_int_cst_lt (max, range_max))
6998     return false;
6999
7000   return true;
7001 }
7002
7003 /* Return true if T (assumed to be a DECL) is a global variable.  */
7004
7005 bool
7006 is_global_var (tree t)
7007 {
7008   if (MTAG_P (t))
7009     return (TREE_STATIC (t) || MTAG_GLOBAL (t));
7010   else
7011     return (TREE_STATIC (t) || DECL_EXTERNAL (t));
7012 }
7013
7014 /* Return true if T (assumed to be a DECL) must be assigned a memory
7015    location.  */
7016
7017 bool
7018 needs_to_live_in_memory (tree t)
7019 {
7020   return (TREE_ADDRESSABLE (t)
7021           || is_global_var (t)
7022           || (TREE_CODE (t) == RESULT_DECL
7023               && aggregate_value_p (t, current_function_decl)));
7024 }
7025
7026 /* There are situations in which a language considers record types
7027    compatible which have different field lists.  Decide if two fields
7028    are compatible.  It is assumed that the parent records are compatible.  */
7029
7030 bool
7031 fields_compatible_p (tree f1, tree f2)
7032 {
7033   if (!operand_equal_p (DECL_FIELD_BIT_OFFSET (f1),
7034                         DECL_FIELD_BIT_OFFSET (f2), OEP_ONLY_CONST))
7035     return false;
7036
7037   if (!operand_equal_p (DECL_FIELD_OFFSET (f1),
7038                         DECL_FIELD_OFFSET (f2), OEP_ONLY_CONST))
7039     return false;
7040
7041   if (!lang_hooks.types_compatible_p (TREE_TYPE (f1), TREE_TYPE (f2)))
7042     return false;
7043
7044   return true;
7045 }
7046
7047 /* Locate within RECORD a field that is compatible with ORIG_FIELD.  */
7048
7049 tree
7050 find_compatible_field (tree record, tree orig_field)
7051 {
7052   tree f;
7053
7054   for (f = TYPE_FIELDS (record); f ; f = TREE_CHAIN (f))
7055     if (TREE_CODE (f) == FIELD_DECL
7056         && fields_compatible_p (f, orig_field))
7057       return f;
7058
7059   /* ??? Why isn't this on the main fields list?  */
7060   f = TYPE_VFIELD (record);
7061   if (f && TREE_CODE (f) == FIELD_DECL
7062       && fields_compatible_p (f, orig_field))
7063     return f;
7064
7065   /* ??? We should abort here, but Java appears to do Bad Things
7066      with inherited fields.  */
7067   return orig_field;
7068 }
7069
7070 /* Return value of a constant X.  */
7071
7072 HOST_WIDE_INT
7073 int_cst_value (tree x)
7074 {
7075   unsigned bits = TYPE_PRECISION (TREE_TYPE (x));
7076   unsigned HOST_WIDE_INT val = TREE_INT_CST_LOW (x);
7077   bool negative = ((val >> (bits - 1)) & 1) != 0;
7078
7079   gcc_assert (bits <= HOST_BITS_PER_WIDE_INT);
7080
7081   if (negative)
7082     val |= (~(unsigned HOST_WIDE_INT) 0) << (bits - 1) << 1;
7083   else
7084     val &= ~((~(unsigned HOST_WIDE_INT) 0) << (bits - 1) << 1);
7085
7086   return val;
7087 }
7088
7089 /* Returns the greatest common divisor of A and B, which must be
7090    INTEGER_CSTs.  */
7091
7092 tree
7093 tree_fold_gcd (tree a, tree b)
7094 {
7095   tree a_mod_b;
7096   tree type = TREE_TYPE (a);
7097
7098   gcc_assert (TREE_CODE (a) == INTEGER_CST);
7099   gcc_assert (TREE_CODE (b) == INTEGER_CST);
7100
7101   if (integer_zerop (a))
7102     return b;
7103
7104   if (integer_zerop (b))
7105     return a;
7106
7107   if (tree_int_cst_sgn (a) == -1)
7108     a = fold_build2 (MULT_EXPR, type, a,
7109                      build_int_cst (type, -1));
7110
7111   if (tree_int_cst_sgn (b) == -1)
7112     b = fold_build2 (MULT_EXPR, type, b,
7113                      build_int_cst (type, -1));
7114
7115   while (1)
7116     {
7117       a_mod_b = fold_build2 (FLOOR_MOD_EXPR, type, a, b);
7118
7119       if (!TREE_INT_CST_LOW (a_mod_b)
7120           && !TREE_INT_CST_HIGH (a_mod_b))
7121         return b;
7122
7123       a = b;
7124       b = a_mod_b;
7125     }
7126 }
7127
7128 /* Returns unsigned variant of TYPE.  */
7129
7130 tree
7131 unsigned_type_for (tree type)
7132 {
7133   if (POINTER_TYPE_P (type))
7134     return lang_hooks.types.unsigned_type (size_type_node);
7135   return lang_hooks.types.unsigned_type (type);
7136 }
7137
7138 /* Returns signed variant of TYPE.  */
7139
7140 tree
7141 signed_type_for (tree type)
7142 {
7143   if (POINTER_TYPE_P (type))
7144     return lang_hooks.types.signed_type (size_type_node);
7145   return lang_hooks.types.signed_type (type);
7146 }
7147
7148 /* Returns the largest value obtainable by casting something in INNER type to
7149    OUTER type.  */
7150
7151 tree
7152 upper_bound_in_type (tree outer, tree inner)
7153 {
7154   unsigned HOST_WIDE_INT lo, hi;
7155   unsigned int det = 0;
7156   unsigned oprec = TYPE_PRECISION (outer);
7157   unsigned iprec = TYPE_PRECISION (inner);
7158   unsigned prec;
7159
7160   /* Compute a unique number for every combination.  */
7161   det |= (oprec > iprec) ? 4 : 0;
7162   det |= TYPE_UNSIGNED (outer) ? 2 : 0;
7163   det |= TYPE_UNSIGNED (inner) ? 1 : 0;
7164
7165   /* Determine the exponent to use.  */
7166   switch (det)
7167     {
7168     case 0:
7169     case 1:
7170       /* oprec <= iprec, outer: signed, inner: don't care.  */
7171       prec = oprec - 1;
7172       break;
7173     case 2:
7174     case 3:
7175       /* oprec <= iprec, outer: unsigned, inner: don't care.  */
7176       prec = oprec;
7177       break;
7178     case 4:
7179       /* oprec > iprec, outer: signed, inner: signed.  */
7180       prec = iprec - 1;
7181       break;
7182     case 5:
7183       /* oprec > iprec, outer: signed, inner: unsigned.  */
7184       prec = iprec;
7185       break;
7186     case 6:
7187       /* oprec > iprec, outer: unsigned, inner: signed.  */
7188       prec = oprec;
7189       break;
7190     case 7:
7191       /* oprec > iprec, outer: unsigned, inner: unsigned.  */
7192       prec = iprec;
7193       break;
7194     default:
7195       gcc_unreachable ();
7196     }
7197
7198   /* Compute 2^^prec - 1.  */
7199   if (prec <= HOST_BITS_PER_WIDE_INT)
7200     {
7201       hi = 0;
7202       lo = ((~(unsigned HOST_WIDE_INT) 0)
7203             >> (HOST_BITS_PER_WIDE_INT - prec));
7204     }
7205   else
7206     {
7207       hi = ((~(unsigned HOST_WIDE_INT) 0)
7208             >> (2 * HOST_BITS_PER_WIDE_INT - prec));
7209       lo = ~(unsigned HOST_WIDE_INT) 0;
7210     }
7211
7212   return build_int_cst_wide (outer, lo, hi);
7213 }
7214
7215 /* Returns the smallest value obtainable by casting something in INNER type to
7216    OUTER type.  */
7217
7218 tree
7219 lower_bound_in_type (tree outer, tree inner)
7220 {
7221   unsigned HOST_WIDE_INT lo, hi;
7222   unsigned oprec = TYPE_PRECISION (outer);
7223   unsigned iprec = TYPE_PRECISION (inner);
7224
7225   /* If OUTER type is unsigned, we can definitely cast 0 to OUTER type
7226      and obtain 0.  */
7227   if (TYPE_UNSIGNED (outer)
7228       /* If we are widening something of an unsigned type, OUTER type
7229          contains all values of INNER type.  In particular, both INNER
7230          and OUTER types have zero in common.  */
7231       || (oprec > iprec && TYPE_UNSIGNED (inner)))
7232     lo = hi = 0;
7233   else
7234     {
7235       /* If we are widening a signed type to another signed type, we
7236          want to obtain -2^^(iprec-1).  If we are keeping the
7237          precision or narrowing to a signed type, we want to obtain
7238          -2^(oprec-1).  */
7239       unsigned prec = oprec > iprec ? iprec : oprec;
7240
7241       if (prec <= HOST_BITS_PER_WIDE_INT)
7242         {
7243           hi = ~(unsigned HOST_WIDE_INT) 0;
7244           lo = (~(unsigned HOST_WIDE_INT) 0) << (prec - 1);
7245         }
7246       else
7247         {
7248           hi = ((~(unsigned HOST_WIDE_INT) 0)
7249                 << (prec - HOST_BITS_PER_WIDE_INT - 1));
7250           lo = 0;
7251         }
7252     }
7253
7254   return build_int_cst_wide (outer, lo, hi);
7255 }
7256
7257 /* Return nonzero if two operands that are suitable for PHI nodes are
7258    necessarily equal.  Specifically, both ARG0 and ARG1 must be either
7259    SSA_NAME or invariant.  Note that this is strictly an optimization.
7260    That is, callers of this function can directly call operand_equal_p
7261    and get the same result, only slower.  */
7262
7263 int
7264 operand_equal_for_phi_arg_p (tree arg0, tree arg1)
7265 {
7266   if (arg0 == arg1)
7267     return 1;
7268   if (TREE_CODE (arg0) == SSA_NAME || TREE_CODE (arg1) == SSA_NAME)
7269     return 0;
7270   return operand_equal_p (arg0, arg1, 0);
7271 }
7272
7273 /* Returns number of zeros at the end of binary representation of X.
7274
7275    ??? Use ffs if available?  */
7276
7277 tree
7278 num_ending_zeros (tree x)
7279 {
7280   unsigned HOST_WIDE_INT fr, nfr;
7281   unsigned num, abits;
7282   tree type = TREE_TYPE (x);
7283
7284   if (TREE_INT_CST_LOW (x) == 0)
7285     {
7286       num = HOST_BITS_PER_WIDE_INT;
7287       fr = TREE_INT_CST_HIGH (x);
7288     }
7289   else
7290     {
7291       num = 0;
7292       fr = TREE_INT_CST_LOW (x);
7293     }
7294
7295   for (abits = HOST_BITS_PER_WIDE_INT / 2; abits; abits /= 2)
7296     {
7297       nfr = fr >> abits;
7298       if (nfr << abits == fr)
7299         {
7300           num += abits;
7301           fr = nfr;
7302         }
7303     }
7304
7305   if (num > TYPE_PRECISION (type))
7306     num = TYPE_PRECISION (type);
7307
7308   return build_int_cst_type (type, num);
7309 }
7310
7311
7312 #define WALK_SUBTREE(NODE)                              \
7313   do                                                    \
7314     {                                                   \
7315       result = walk_tree (&(NODE), func, data, pset);   \
7316       if (result)                                       \
7317         return result;                                  \
7318     }                                                   \
7319   while (0)
7320
7321 /* This is a subroutine of walk_tree that walks field of TYPE that are to
7322    be walked whenever a type is seen in the tree.  Rest of operands and return
7323    value are as for walk_tree.  */
7324
7325 static tree
7326 walk_type_fields (tree type, walk_tree_fn func, void *data,
7327                   struct pointer_set_t *pset)
7328 {
7329   tree result = NULL_TREE;
7330
7331   switch (TREE_CODE (type))
7332     {
7333     case POINTER_TYPE:
7334     case REFERENCE_TYPE:
7335       /* We have to worry about mutually recursive pointers.  These can't
7336          be written in C.  They can in Ada.  It's pathological, but
7337          there's an ACATS test (c38102a) that checks it.  Deal with this
7338          by checking if we're pointing to another pointer, that one
7339          points to another pointer, that one does too, and we have no htab.
7340          If so, get a hash table.  We check three levels deep to avoid
7341          the cost of the hash table if we don't need one.  */
7342       if (POINTER_TYPE_P (TREE_TYPE (type))
7343           && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (type)))
7344           && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (TREE_TYPE (type))))
7345           && !pset)
7346         {
7347           result = walk_tree_without_duplicates (&TREE_TYPE (type),
7348                                                  func, data);
7349           if (result)
7350             return result;
7351
7352           break;
7353         }
7354
7355       /* ... fall through ... */
7356
7357     case COMPLEX_TYPE:
7358       WALK_SUBTREE (TREE_TYPE (type));
7359       break;
7360
7361     case METHOD_TYPE:
7362       WALK_SUBTREE (TYPE_METHOD_BASETYPE (type));
7363
7364       /* Fall through.  */
7365
7366     case FUNCTION_TYPE:
7367       WALK_SUBTREE (TREE_TYPE (type));
7368       {
7369         tree arg;
7370
7371         /* We never want to walk into default arguments.  */
7372         for (arg = TYPE_ARG_TYPES (type); arg; arg = TREE_CHAIN (arg))
7373           WALK_SUBTREE (TREE_VALUE (arg));
7374       }
7375       break;
7376
7377     case ARRAY_TYPE:
7378       /* Don't follow this nodes's type if a pointer for fear that we'll
7379          have infinite recursion.  Those types are uninteresting anyway.  */
7380       if (!POINTER_TYPE_P (TREE_TYPE (type))
7381           && TREE_CODE (TREE_TYPE (type)) != OFFSET_TYPE)
7382         WALK_SUBTREE (TREE_TYPE (type));
7383       WALK_SUBTREE (TYPE_DOMAIN (type));
7384       break;
7385
7386     case BOOLEAN_TYPE:
7387     case ENUMERAL_TYPE:
7388     case INTEGER_TYPE:
7389     case REAL_TYPE:
7390       WALK_SUBTREE (TYPE_MIN_VALUE (type));
7391       WALK_SUBTREE (TYPE_MAX_VALUE (type));
7392       break;
7393
7394     case OFFSET_TYPE:
7395       WALK_SUBTREE (TREE_TYPE (type));
7396       WALK_SUBTREE (TYPE_OFFSET_BASETYPE (type));
7397       break;
7398
7399     default:
7400       break;
7401     }
7402
7403   return NULL_TREE;
7404 }
7405
7406 /* Apply FUNC to all the sub-trees of TP in a pre-order traversal.  FUNC is
7407    called with the DATA and the address of each sub-tree.  If FUNC returns a
7408    non-NULL value, the traversal is stopped, and the value returned by FUNC
7409    is returned.  If PSET is non-NULL it is used to record the nodes visited,
7410    and to avoid visiting a node more than once.  */
7411
7412 tree
7413 walk_tree (tree *tp, walk_tree_fn func, void *data, struct pointer_set_t *pset)
7414 {
7415   enum tree_code code;
7416   int walk_subtrees;
7417   tree result;
7418
7419 #define WALK_SUBTREE_TAIL(NODE)                         \
7420   do                                                    \
7421     {                                                   \
7422        tp = & (NODE);                                   \
7423        goto tail_recurse;                               \
7424     }                                                   \
7425   while (0)
7426
7427  tail_recurse:
7428   /* Skip empty subtrees.  */
7429   if (!*tp)
7430     return NULL_TREE;
7431
7432   /* Don't walk the same tree twice, if the user has requested
7433      that we avoid doing so.  */
7434   if (pset && pointer_set_insert (pset, *tp))
7435     return NULL_TREE;
7436
7437   /* Call the function.  */
7438   walk_subtrees = 1;
7439   result = (*func) (tp, &walk_subtrees, data);
7440
7441   /* If we found something, return it.  */
7442   if (result)
7443     return result;
7444
7445   code = TREE_CODE (*tp);
7446
7447   /* Even if we didn't, FUNC may have decided that there was nothing
7448      interesting below this point in the tree.  */
7449   if (!walk_subtrees)
7450     {
7451       /* But we still need to check our siblings.  */
7452       if (code == TREE_LIST)
7453         WALK_SUBTREE_TAIL (TREE_CHAIN (*tp));
7454       else if (code == OMP_CLAUSE)
7455         WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7456       else
7457         return NULL_TREE;
7458     }
7459
7460   result = lang_hooks.tree_inlining.walk_subtrees (tp, &walk_subtrees, func,
7461                                                    data, pset);
7462   if (result || ! walk_subtrees)
7463     return result;
7464
7465   switch (code)
7466     {
7467     case ERROR_MARK:
7468     case IDENTIFIER_NODE:
7469     case INTEGER_CST:
7470     case REAL_CST:
7471     case VECTOR_CST:
7472     case STRING_CST:
7473     case BLOCK:
7474     case PLACEHOLDER_EXPR:
7475     case SSA_NAME:
7476     case FIELD_DECL:
7477     case RESULT_DECL:
7478       /* None of these have subtrees other than those already walked
7479          above.  */
7480       break;
7481
7482     case TREE_LIST:
7483       WALK_SUBTREE (TREE_VALUE (*tp));
7484       WALK_SUBTREE_TAIL (TREE_CHAIN (*tp));
7485       break;
7486
7487     case TREE_VEC:
7488       {
7489         int len = TREE_VEC_LENGTH (*tp);
7490
7491         if (len == 0)
7492           break;
7493
7494         /* Walk all elements but the first.  */
7495         while (--len)
7496           WALK_SUBTREE (TREE_VEC_ELT (*tp, len));
7497
7498         /* Now walk the first one as a tail call.  */
7499         WALK_SUBTREE_TAIL (TREE_VEC_ELT (*tp, 0));
7500       }
7501
7502     case COMPLEX_CST:
7503       WALK_SUBTREE (TREE_REALPART (*tp));
7504       WALK_SUBTREE_TAIL (TREE_IMAGPART (*tp));
7505
7506     case CONSTRUCTOR:
7507       {
7508         unsigned HOST_WIDE_INT idx;
7509         constructor_elt *ce;
7510
7511         for (idx = 0;
7512              VEC_iterate(constructor_elt, CONSTRUCTOR_ELTS (*tp), idx, ce);
7513              idx++)
7514           WALK_SUBTREE (ce->value);
7515       }
7516       break;
7517
7518     case SAVE_EXPR:
7519       WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, 0));
7520
7521     case BIND_EXPR:
7522       {
7523         tree decl;
7524         for (decl = BIND_EXPR_VARS (*tp); decl; decl = TREE_CHAIN (decl))
7525           {
7526             /* Walk the DECL_INITIAL and DECL_SIZE.  We don't want to walk
7527                into declarations that are just mentioned, rather than
7528                declared; they don't really belong to this part of the tree.
7529                And, we can see cycles: the initializer for a declaration
7530                can refer to the declaration itself.  */
7531             WALK_SUBTREE (DECL_INITIAL (decl));
7532             WALK_SUBTREE (DECL_SIZE (decl));
7533             WALK_SUBTREE (DECL_SIZE_UNIT (decl));
7534           }
7535         WALK_SUBTREE_TAIL (BIND_EXPR_BODY (*tp));
7536       }
7537
7538     case STATEMENT_LIST:
7539       {
7540         tree_stmt_iterator i;
7541         for (i = tsi_start (*tp); !tsi_end_p (i); tsi_next (&i))
7542           WALK_SUBTREE (*tsi_stmt_ptr (i));
7543       }
7544       break;
7545
7546     case OMP_CLAUSE:
7547       switch (OMP_CLAUSE_CODE (*tp))
7548         {
7549         case OMP_CLAUSE_PRIVATE:
7550         case OMP_CLAUSE_SHARED:
7551         case OMP_CLAUSE_FIRSTPRIVATE:
7552         case OMP_CLAUSE_LASTPRIVATE:
7553         case OMP_CLAUSE_COPYIN:
7554         case OMP_CLAUSE_COPYPRIVATE:
7555         case OMP_CLAUSE_IF:
7556         case OMP_CLAUSE_NUM_THREADS:
7557         case OMP_CLAUSE_SCHEDULE:
7558           WALK_SUBTREE (OMP_CLAUSE_OPERAND (*tp, 0));
7559           /* FALLTHRU */
7560
7561         case OMP_CLAUSE_NOWAIT:
7562         case OMP_CLAUSE_ORDERED:
7563         case OMP_CLAUSE_DEFAULT:
7564           WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7565
7566         case OMP_CLAUSE_REDUCTION:
7567           {
7568             int i;
7569             for (i = 0; i < 4; i++)
7570               WALK_SUBTREE (OMP_CLAUSE_OPERAND (*tp, i));
7571             WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7572           }
7573
7574         default:
7575           gcc_unreachable ();
7576         }
7577       break;
7578
7579     case TARGET_EXPR:
7580       {
7581         int i, len;
7582
7583         /* TARGET_EXPRs are peculiar: operands 1 and 3 can be the same.
7584            But, we only want to walk once.  */
7585         len = (TREE_OPERAND (*tp, 3) == TREE_OPERAND (*tp, 1)) ? 2 : 3;
7586         for (i = 0; i < len; ++i)
7587           WALK_SUBTREE (TREE_OPERAND (*tp, i));
7588         WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, len));
7589       }
7590
7591     case DECL_EXPR:
7592       /* Walk into various fields of the type that it's defining.  We only
7593          want to walk into these fields of a type in this case.  Note that
7594          decls get walked as part of the processing of a BIND_EXPR.
7595
7596          ??? Precisely which fields of types that we are supposed to walk in
7597          this case vs. the normal case aren't well defined.  */
7598       if (TREE_CODE (DECL_EXPR_DECL (*tp)) == TYPE_DECL
7599           && TREE_CODE (TREE_TYPE (DECL_EXPR_DECL (*tp))) != ERROR_MARK)
7600         {
7601           tree *type_p = &TREE_TYPE (DECL_EXPR_DECL (*tp));
7602
7603           /* Call the function for the type.  See if it returns anything or
7604              doesn't want us to continue.  If we are to continue, walk both
7605              the normal fields and those for the declaration case.  */
7606           result = (*func) (type_p, &walk_subtrees, data);
7607           if (result || !walk_subtrees)
7608             return NULL_TREE;
7609
7610           result = walk_type_fields (*type_p, func, data, pset);
7611           if (result)
7612             return result;
7613
7614           /* If this is a record type, also walk the fields.  */
7615           if (TREE_CODE (*type_p) == RECORD_TYPE
7616               || TREE_CODE (*type_p) == UNION_TYPE
7617               || TREE_CODE (*type_p) == QUAL_UNION_TYPE)
7618             {
7619               tree field;
7620
7621               for (field = TYPE_FIELDS (*type_p); field;
7622                    field = TREE_CHAIN (field))
7623                 {
7624                   /* We'd like to look at the type of the field, but we can
7625                      easily get infinite recursion.  So assume it's pointed
7626                      to elsewhere in the tree.  Also, ignore things that
7627                      aren't fields.  */
7628                   if (TREE_CODE (field) != FIELD_DECL)
7629                     continue;
7630
7631                   WALK_SUBTREE (DECL_FIELD_OFFSET (field));
7632                   WALK_SUBTREE (DECL_SIZE (field));
7633                   WALK_SUBTREE (DECL_SIZE_UNIT (field));
7634                   if (TREE_CODE (*type_p) == QUAL_UNION_TYPE)
7635                     WALK_SUBTREE (DECL_QUALIFIER (field));
7636                 }
7637             }
7638
7639           WALK_SUBTREE (TYPE_SIZE (*type_p));
7640           WALK_SUBTREE_TAIL (TYPE_SIZE_UNIT (*type_p));
7641         }
7642       /* FALLTHRU */
7643
7644     default:
7645       if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
7646         {
7647           int i, len;
7648
7649           /* Walk over all the sub-trees of this operand.  */
7650           len = TREE_CODE_LENGTH (code);
7651
7652           /* Go through the subtrees.  We need to do this in forward order so
7653              that the scope of a FOR_EXPR is handled properly.  */
7654           if (len)
7655             {
7656               for (i = 0; i < len - 1; ++i)
7657                 WALK_SUBTREE (TREE_OPERAND (*tp, i));
7658               WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, len - 1));
7659             }
7660         }
7661
7662       /* If this is a type, walk the needed fields in the type.  */
7663       else if (TYPE_P (*tp))
7664         return walk_type_fields (*tp, func, data, pset);
7665       break;
7666     }
7667
7668   /* We didn't find what we were looking for.  */
7669   return NULL_TREE;
7670
7671 #undef WALK_SUBTREE_TAIL
7672 }
7673 #undef WALK_SUBTREE
7674
7675 /* Like walk_tree, but does not walk duplicate nodes more than once.  */
7676
7677 tree
7678 walk_tree_without_duplicates (tree *tp, walk_tree_fn func, void *data)
7679 {
7680   tree result;
7681   struct pointer_set_t *pset;
7682
7683   pset = pointer_set_create ();
7684   result = walk_tree (tp, func, data, pset);
7685   pointer_set_destroy (pset);
7686   return result;
7687 }
7688
7689
7690 /* Return true if STMT is an empty statement or contains nothing but
7691    empty statements.  */
7692
7693 bool
7694 empty_body_p (tree stmt)
7695 {
7696   tree_stmt_iterator i;
7697   tree body;
7698
7699   if (IS_EMPTY_STMT (stmt))
7700     return true;
7701   else if (TREE_CODE (stmt) == BIND_EXPR)
7702     body = BIND_EXPR_BODY (stmt);
7703   else if (TREE_CODE (stmt) == STATEMENT_LIST)
7704     body = stmt;
7705   else
7706     return false;
7707
7708   for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i))
7709     if (!empty_body_p (tsi_stmt (i)))
7710       return false;
7711
7712   return true;
7713 }
7714
7715 #include "gt-tree.h"