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 build6_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3099              tree arg2, tree arg3, tree arg4, tree arg5 MEM_STAT_DECL)
3100 {
3101   bool constant, read_only, side_effects, invariant;
3102   tree t;
3103
3104   gcc_assert (TREE_CODE_LENGTH (code) == 6);
3105
3106   t = make_node_stat (code PASS_MEM_STAT);
3107   TREE_TYPE (t) = tt;
3108
3109   side_effects = TREE_SIDE_EFFECTS (t);
3110
3111   PROCESS_ARG(0);
3112   PROCESS_ARG(1);
3113   PROCESS_ARG(2);
3114   PROCESS_ARG(3);
3115   PROCESS_ARG(4);
3116   PROCESS_ARG(5);
3117
3118   TREE_SIDE_EFFECTS (t) = side_effects;
3119   TREE_THIS_VOLATILE (t)
3120     = (TREE_CODE_CLASS (code) == tcc_reference
3121        && arg0 && TREE_THIS_VOLATILE (arg0));
3122
3123   return t;
3124 }
3125
3126 tree
3127 build7_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3128              tree arg2, tree arg3, tree arg4, tree arg5,
3129              tree arg6 MEM_STAT_DECL)
3130 {
3131   bool constant, read_only, side_effects, invariant;
3132   tree t;
3133
3134   gcc_assert (code == TARGET_MEM_REF);
3135
3136   t = make_node_stat (code PASS_MEM_STAT);
3137   TREE_TYPE (t) = tt;
3138
3139   side_effects = TREE_SIDE_EFFECTS (t);
3140
3141   PROCESS_ARG(0);
3142   PROCESS_ARG(1);
3143   PROCESS_ARG(2);
3144   PROCESS_ARG(3);
3145   PROCESS_ARG(4);
3146   PROCESS_ARG(5);
3147   PROCESS_ARG(6);
3148
3149   TREE_SIDE_EFFECTS (t) = side_effects;
3150   TREE_THIS_VOLATILE (t) = 0;
3151
3152   return t;
3153 }
3154
3155 /* Similar except don't specify the TREE_TYPE
3156    and leave the TREE_SIDE_EFFECTS as 0.
3157    It is permissible for arguments to be null,
3158    or even garbage if their values do not matter.  */
3159
3160 tree
3161 build_nt (enum tree_code code, ...)
3162 {
3163   tree t;
3164   int length;
3165   int i;
3166   va_list p;
3167
3168   va_start (p, code);
3169
3170   t = make_node (code);
3171   length = TREE_CODE_LENGTH (code);
3172
3173   for (i = 0; i < length; i++)
3174     TREE_OPERAND (t, i) = va_arg (p, tree);
3175
3176   va_end (p);
3177   return t;
3178 }
3179 \f
3180 /* Create a DECL_... node of code CODE, name NAME and data type TYPE.
3181    We do NOT enter this node in any sort of symbol table.
3182
3183    layout_decl is used to set up the decl's storage layout.
3184    Other slots are initialized to 0 or null pointers.  */
3185
3186 tree
3187 build_decl_stat (enum tree_code code, tree name, tree type MEM_STAT_DECL)
3188 {
3189   tree t;
3190
3191   t = make_node_stat (code PASS_MEM_STAT);
3192
3193 /*  if (type == error_mark_node)
3194     type = integer_type_node; */
3195 /* That is not done, deliberately, so that having error_mark_node
3196    as the type can suppress useless errors in the use of this variable.  */
3197
3198   DECL_NAME (t) = name;
3199   TREE_TYPE (t) = type;
3200
3201   if (code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL)
3202     layout_decl (t, 0);
3203   else if (code == FUNCTION_DECL)
3204     DECL_MODE (t) = FUNCTION_MODE;
3205
3206   return t;
3207 }
3208
3209 /* Builds and returns function declaration with NAME and TYPE.  */
3210
3211 tree
3212 build_fn_decl (const char *name, tree type)
3213 {
3214   tree id = get_identifier (name);
3215   tree decl = build_decl (FUNCTION_DECL, id, type);
3216
3217   DECL_EXTERNAL (decl) = 1;
3218   TREE_PUBLIC (decl) = 1;
3219   DECL_ARTIFICIAL (decl) = 1;
3220   TREE_NOTHROW (decl) = 1;
3221
3222   return decl;
3223 }
3224
3225 \f
3226 /* BLOCK nodes are used to represent the structure of binding contours
3227    and declarations, once those contours have been exited and their contents
3228    compiled.  This information is used for outputting debugging info.  */
3229
3230 tree
3231 build_block (tree vars, tree subblocks, tree supercontext, tree chain)
3232 {
3233   tree block = make_node (BLOCK);
3234
3235   BLOCK_VARS (block) = vars;
3236   BLOCK_SUBBLOCKS (block) = subblocks;
3237   BLOCK_SUPERCONTEXT (block) = supercontext;
3238   BLOCK_CHAIN (block) = chain;
3239   return block;
3240 }
3241
3242 #if 1 /* ! defined(USE_MAPPED_LOCATION) */
3243 /* ??? gengtype doesn't handle conditionals */
3244 static GTY(()) source_locus last_annotated_node;
3245 #endif
3246
3247 #ifdef USE_MAPPED_LOCATION
3248
3249 expanded_location
3250 expand_location (source_location loc)
3251 {
3252   expanded_location xloc;
3253   if (loc == 0) { xloc.file = NULL; xloc.line = 0;  xloc.column = 0; }
3254   else
3255     {
3256       const struct line_map *map = linemap_lookup (&line_table, loc);
3257       xloc.file = map->to_file;
3258       xloc.line = SOURCE_LINE (map, loc);
3259       xloc.column = SOURCE_COLUMN (map, loc);
3260     };
3261   return xloc;
3262 }
3263
3264 #else
3265
3266 /* Record the exact location where an expression or an identifier were
3267    encountered.  */
3268
3269 void
3270 annotate_with_file_line (tree node, const char *file, int line)
3271 {
3272   /* Roughly one percent of the calls to this function are to annotate
3273      a node with the same information already attached to that node!
3274      Just return instead of wasting memory.  */
3275   if (EXPR_LOCUS (node)
3276       && EXPR_LINENO (node) == line
3277       && (EXPR_FILENAME (node) == file
3278           || !strcmp (EXPR_FILENAME (node), file)))
3279     {
3280       last_annotated_node = EXPR_LOCUS (node);
3281       return;
3282     }
3283
3284   /* In heavily macroized code (such as GCC itself) this single
3285      entry cache can reduce the number of allocations by more
3286      than half.  */
3287   if (last_annotated_node
3288       && last_annotated_node->line == line
3289       && (last_annotated_node->file == file
3290           || !strcmp (last_annotated_node->file, file)))
3291     {
3292       SET_EXPR_LOCUS (node, last_annotated_node);
3293       return;
3294     }
3295
3296   SET_EXPR_LOCUS (node, ggc_alloc (sizeof (location_t)));
3297   EXPR_LINENO (node) = line;
3298   EXPR_FILENAME (node) = file;
3299   last_annotated_node = EXPR_LOCUS (node);
3300 }
3301
3302 void
3303 annotate_with_locus (tree node, location_t locus)
3304 {
3305   annotate_with_file_line (node, locus.file, locus.line);
3306 }
3307 #endif
3308 \f
3309 /* Return a declaration like DDECL except that its DECL_ATTRIBUTES
3310    is ATTRIBUTE.  */
3311
3312 tree
3313 build_decl_attribute_variant (tree ddecl, tree attribute)
3314 {
3315   DECL_ATTRIBUTES (ddecl) = attribute;
3316   return ddecl;
3317 }
3318
3319 /* Borrowed from hashtab.c iterative_hash implementation.  */
3320 #define mix(a,b,c) \
3321 { \
3322   a -= b; a -= c; a ^= (c>>13); \
3323   b -= c; b -= a; b ^= (a<< 8); \
3324   c -= a; c -= b; c ^= ((b&0xffffffff)>>13); \
3325   a -= b; a -= c; a ^= ((c&0xffffffff)>>12); \
3326   b -= c; b -= a; b = (b ^ (a<<16)) & 0xffffffff; \
3327   c -= a; c -= b; c = (c ^ (b>> 5)) & 0xffffffff; \
3328   a -= b; a -= c; a = (a ^ (c>> 3)) & 0xffffffff; \
3329   b -= c; b -= a; b = (b ^ (a<<10)) & 0xffffffff; \
3330   c -= a; c -= b; c = (c ^ (b>>15)) & 0xffffffff; \
3331 }
3332
3333
3334 /* Produce good hash value combining VAL and VAL2.  */
3335 static inline hashval_t
3336 iterative_hash_hashval_t (hashval_t val, hashval_t val2)
3337 {
3338   /* the golden ratio; an arbitrary value.  */
3339   hashval_t a = 0x9e3779b9;
3340
3341   mix (a, val, val2);
3342   return val2;
3343 }
3344
3345 /* Produce good hash value combining PTR and VAL2.  */
3346 static inline hashval_t
3347 iterative_hash_pointer (void *ptr, hashval_t val2)
3348 {
3349   if (sizeof (ptr) == sizeof (hashval_t))
3350     return iterative_hash_hashval_t ((size_t) ptr, val2);
3351   else
3352     {
3353       hashval_t a = (hashval_t) (size_t) ptr;
3354       /* Avoid warnings about shifting of more than the width of the type on
3355          hosts that won't execute this path.  */
3356       int zero = 0;
3357       hashval_t b = (hashval_t) ((size_t) ptr >> (sizeof (hashval_t) * 8 + zero));
3358       mix (a, b, val2);
3359       return val2;
3360     }
3361 }
3362
3363 /* Produce good hash value combining VAL and VAL2.  */
3364 static inline hashval_t
3365 iterative_hash_host_wide_int (HOST_WIDE_INT val, hashval_t val2)
3366 {
3367   if (sizeof (HOST_WIDE_INT) == sizeof (hashval_t))
3368     return iterative_hash_hashval_t (val, val2);
3369   else
3370     {
3371       hashval_t a = (hashval_t) val;
3372       /* Avoid warnings about shifting of more than the width of the type on
3373          hosts that won't execute this path.  */
3374       int zero = 0;
3375       hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 8 + zero));
3376       mix (a, b, val2);
3377       if (sizeof (HOST_WIDE_INT) > 2 * sizeof (hashval_t))
3378         {
3379           hashval_t a = (hashval_t) (val >> (sizeof (hashval_t) * 16 + zero));
3380           hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 24 + zero));
3381           mix (a, b, val2);
3382         }
3383       return val2;
3384     }
3385 }
3386
3387 /* Return a type like TTYPE except that its TYPE_ATTRIBUTE
3388    is ATTRIBUTE.
3389
3390    Record such modified types already made so we don't make duplicates.  */
3391
3392 tree
3393 build_type_attribute_variant (tree ttype, tree attribute)
3394 {
3395   if (! attribute_list_equal (TYPE_ATTRIBUTES (ttype), attribute))
3396     {
3397       hashval_t hashcode = 0;
3398       tree ntype;
3399       enum tree_code code = TREE_CODE (ttype);
3400
3401       ntype = copy_node (ttype);
3402
3403       TYPE_POINTER_TO (ntype) = 0;
3404       TYPE_REFERENCE_TO (ntype) = 0;
3405       TYPE_ATTRIBUTES (ntype) = attribute;
3406
3407       /* Create a new main variant of TYPE.  */
3408       TYPE_MAIN_VARIANT (ntype) = ntype;
3409       TYPE_NEXT_VARIANT (ntype) = 0;
3410       set_type_quals (ntype, TYPE_UNQUALIFIED);
3411
3412       hashcode = iterative_hash_object (code, hashcode);
3413       if (TREE_TYPE (ntype))
3414         hashcode = iterative_hash_object (TYPE_HASH (TREE_TYPE (ntype)),
3415                                           hashcode);
3416       hashcode = attribute_hash_list (attribute, hashcode);
3417
3418       switch (TREE_CODE (ntype))
3419         {
3420         case FUNCTION_TYPE:
3421           hashcode = type_hash_list (TYPE_ARG_TYPES (ntype), hashcode);
3422           break;
3423         case ARRAY_TYPE:
3424           hashcode = iterative_hash_object (TYPE_HASH (TYPE_DOMAIN (ntype)),
3425                                             hashcode);
3426           break;
3427         case INTEGER_TYPE:
3428           hashcode = iterative_hash_object
3429             (TREE_INT_CST_LOW (TYPE_MAX_VALUE (ntype)), hashcode);
3430           hashcode = iterative_hash_object
3431             (TREE_INT_CST_HIGH (TYPE_MAX_VALUE (ntype)), hashcode);
3432           break;
3433         case REAL_TYPE:
3434           {
3435             unsigned int precision = TYPE_PRECISION (ntype);
3436             hashcode = iterative_hash_object (precision, hashcode);
3437           }
3438           break;
3439         default:
3440           break;
3441         }
3442
3443       ntype = type_hash_canon (hashcode, ntype);
3444       ttype = build_qualified_type (ntype, TYPE_QUALS (ttype));
3445     }
3446
3447   return ttype;
3448 }
3449
3450
3451 /* Return nonzero if IDENT is a valid name for attribute ATTR,
3452    or zero if not.
3453
3454    We try both `text' and `__text__', ATTR may be either one.  */
3455 /* ??? It might be a reasonable simplification to require ATTR to be only
3456    `text'.  One might then also require attribute lists to be stored in
3457    their canonicalized form.  */
3458
3459 static int
3460 is_attribute_with_length_p (const char *attr, int attr_len, tree ident)
3461 {
3462   int ident_len;
3463   const char *p;
3464
3465   if (TREE_CODE (ident) != IDENTIFIER_NODE)
3466     return 0;
3467
3468   p = IDENTIFIER_POINTER (ident);
3469   ident_len = IDENTIFIER_LENGTH (ident);
3470
3471   if (ident_len == attr_len
3472       && strcmp (attr, p) == 0)
3473     return 1;
3474
3475   /* If ATTR is `__text__', IDENT must be `text'; and vice versa.  */
3476   if (attr[0] == '_')
3477     {
3478       gcc_assert (attr[1] == '_');
3479       gcc_assert (attr[attr_len - 2] == '_');
3480       gcc_assert (attr[attr_len - 1] == '_');
3481       if (ident_len == attr_len - 4
3482           && strncmp (attr + 2, p, attr_len - 4) == 0)
3483         return 1;
3484     }
3485   else
3486     {
3487       if (ident_len == attr_len + 4
3488           && p[0] == '_' && p[1] == '_'
3489           && p[ident_len - 2] == '_' && p[ident_len - 1] == '_'
3490           && strncmp (attr, p + 2, attr_len) == 0)
3491         return 1;
3492     }
3493
3494   return 0;
3495 }
3496
3497 /* Return nonzero if IDENT is a valid name for attribute ATTR,
3498    or zero if not.
3499
3500    We try both `text' and `__text__', ATTR may be either one.  */
3501
3502 int
3503 is_attribute_p (const char *attr, tree ident)
3504 {
3505   return is_attribute_with_length_p (attr, strlen (attr), ident);
3506 }
3507
3508 /* Given an attribute name and a list of attributes, return a pointer to the
3509    attribute's list element if the attribute is part of the list, or NULL_TREE
3510    if not found.  If the attribute appears more than once, this only
3511    returns the first occurrence; the TREE_CHAIN of the return value should
3512    be passed back in if further occurrences are wanted.  */
3513
3514 tree
3515 lookup_attribute (const char *attr_name, tree list)
3516 {
3517   tree l;
3518   size_t attr_len = strlen (attr_name);
3519
3520   for (l = list; l; l = TREE_CHAIN (l))
3521     {
3522       gcc_assert (TREE_CODE (TREE_PURPOSE (l)) == IDENTIFIER_NODE);
3523       if (is_attribute_with_length_p (attr_name, attr_len, TREE_PURPOSE (l)))
3524         return l;
3525     }
3526
3527   return NULL_TREE;
3528 }
3529
3530 /* Remove any instances of attribute ATTR_NAME in LIST and return the
3531    modified list.  */
3532
3533 tree
3534 remove_attribute (const char *attr_name, tree list)
3535 {
3536   tree *p;
3537   size_t attr_len = strlen (attr_name);
3538
3539   for (p = &list; *p; )
3540     {
3541       tree l = *p;
3542       gcc_assert (TREE_CODE (TREE_PURPOSE (l)) == IDENTIFIER_NODE);
3543       if (is_attribute_with_length_p (attr_name, attr_len, TREE_PURPOSE (l)))
3544         *p = TREE_CHAIN (l);
3545       else
3546         p = &TREE_CHAIN (l);
3547     }
3548
3549   return list;
3550 }
3551
3552 /* Return an attribute list that is the union of a1 and a2.  */
3553
3554 tree
3555 merge_attributes (tree a1, tree a2)
3556 {
3557   tree attributes;
3558
3559   /* Either one unset?  Take the set one.  */
3560
3561   if ((attributes = a1) == 0)
3562     attributes = a2;
3563
3564   /* One that completely contains the other?  Take it.  */
3565
3566   else if (a2 != 0 && ! attribute_list_contained (a1, a2))
3567     {
3568       if (attribute_list_contained (a2, a1))
3569         attributes = a2;
3570       else
3571         {
3572           /* Pick the longest list, and hang on the other list.  */
3573
3574           if (list_length (a1) < list_length (a2))
3575             attributes = a2, a2 = a1;
3576
3577           for (; a2 != 0; a2 = TREE_CHAIN (a2))
3578             {
3579               tree a;
3580               for (a = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
3581                                          attributes);
3582                    a != NULL_TREE;
3583                    a = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
3584                                          TREE_CHAIN (a)))
3585                 {
3586                   if (TREE_VALUE (a) != NULL
3587                       && TREE_CODE (TREE_VALUE (a)) == TREE_LIST
3588                       && TREE_VALUE (a2) != NULL
3589                       && TREE_CODE (TREE_VALUE (a2)) == TREE_LIST)
3590                     {
3591                       if (simple_cst_list_equal (TREE_VALUE (a),
3592                                                  TREE_VALUE (a2)) == 1)
3593                         break;
3594                     }
3595                   else if (simple_cst_equal (TREE_VALUE (a),
3596                                              TREE_VALUE (a2)) == 1)
3597                     break;
3598                 }
3599               if (a == NULL_TREE)
3600                 {
3601                   a1 = copy_node (a2);
3602                   TREE_CHAIN (a1) = attributes;
3603                   attributes = a1;
3604                 }
3605             }
3606         }
3607     }
3608   return attributes;
3609 }
3610
3611 /* Given types T1 and T2, merge their attributes and return
3612   the result.  */
3613
3614 tree
3615 merge_type_attributes (tree t1, tree t2)
3616 {
3617   return merge_attributes (TYPE_ATTRIBUTES (t1),
3618                            TYPE_ATTRIBUTES (t2));
3619 }
3620
3621 /* Given decls OLDDECL and NEWDECL, merge their attributes and return
3622    the result.  */
3623
3624 tree
3625 merge_decl_attributes (tree olddecl, tree newdecl)
3626 {
3627   return merge_attributes (DECL_ATTRIBUTES (olddecl),
3628                            DECL_ATTRIBUTES (newdecl));
3629 }
3630
3631 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
3632
3633 /* Specialization of merge_decl_attributes for various Windows targets.
3634
3635    This handles the following situation:
3636
3637      __declspec (dllimport) int foo;
3638      int foo;
3639
3640    The second instance of `foo' nullifies the dllimport.  */
3641
3642 tree
3643 merge_dllimport_decl_attributes (tree old, tree new)
3644 {
3645   tree a;
3646   int delete_dllimport_p = 1;
3647
3648   /* What we need to do here is remove from `old' dllimport if it doesn't
3649      appear in `new'.  dllimport behaves like extern: if a declaration is
3650      marked dllimport and a definition appears later, then the object
3651      is not dllimport'd.  We also remove a `new' dllimport if the old list
3652      contains dllexport:  dllexport always overrides dllimport, regardless
3653      of the order of declaration.  */
3654   if (!VAR_OR_FUNCTION_DECL_P (new))
3655     delete_dllimport_p = 0;
3656   else if (DECL_DLLIMPORT_P (new)
3657            && lookup_attribute ("dllexport", DECL_ATTRIBUTES (old)))
3658     {
3659       DECL_DLLIMPORT_P (new) = 0;
3660       warning (OPT_Wattributes, "%q+D already declared with dllexport attribute: "
3661               "dllimport ignored", new);
3662     }
3663   else if (DECL_DLLIMPORT_P (old) && !DECL_DLLIMPORT_P (new))
3664     {
3665       /* Warn about overriding a symbol that has already been used. eg:
3666            extern int __attribute__ ((dllimport)) foo;
3667            int* bar () {return &foo;}
3668            int foo;
3669       */
3670       if (TREE_USED (old))
3671         {
3672           warning (0, "%q+D redeclared without dllimport attribute "
3673                    "after being referenced with dll linkage", new);
3674           /* If we have used a variable's address with dllimport linkage,
3675               keep the old DECL_DLLIMPORT_P flag: the ADDR_EXPR using the
3676               decl may already have had TREE_INVARIANT and TREE_CONSTANT
3677               computed.
3678               We still remove the attribute so that assembler code refers
3679               to '&foo rather than '_imp__foo'.  */
3680           if (TREE_CODE (old) == VAR_DECL && TREE_ADDRESSABLE (old))
3681             DECL_DLLIMPORT_P (new) = 1;
3682         }
3683
3684       /* Let an inline definition silently override the external reference,
3685          but otherwise warn about attribute inconsistency.  */
3686       else if (TREE_CODE (new) == VAR_DECL
3687                || !DECL_DECLARED_INLINE_P (new))
3688         warning (OPT_Wattributes, "%q+D redeclared without dllimport attribute: "
3689                   "previous dllimport ignored", new);
3690     }
3691   else
3692     delete_dllimport_p = 0;
3693
3694   a = merge_attributes (DECL_ATTRIBUTES (old), DECL_ATTRIBUTES (new));
3695
3696   if (delete_dllimport_p)
3697     {
3698       tree prev, t;
3699       const size_t attr_len = strlen ("dllimport");
3700
3701       /* Scan the list for dllimport and delete it.  */
3702       for (prev = NULL_TREE, t = a; t; prev = t, t = TREE_CHAIN (t))
3703         {
3704           if (is_attribute_with_length_p ("dllimport", attr_len,
3705                                           TREE_PURPOSE (t)))
3706             {
3707               if (prev == NULL_TREE)
3708                 a = TREE_CHAIN (a);
3709               else
3710                 TREE_CHAIN (prev) = TREE_CHAIN (t);
3711               break;
3712             }
3713         }
3714     }
3715
3716   return a;
3717 }
3718
3719 /* Handle a "dllimport" or "dllexport" attribute; arguments as in
3720    struct attribute_spec.handler.  */
3721
3722 tree
3723 handle_dll_attribute (tree * pnode, tree name, tree args, int flags,
3724                       bool *no_add_attrs)
3725 {
3726   tree node = *pnode;
3727
3728   /* These attributes may apply to structure and union types being created,
3729      but otherwise should pass to the declaration involved.  */
3730   if (!DECL_P (node))
3731     {
3732       if (flags & ((int) ATTR_FLAG_DECL_NEXT | (int) ATTR_FLAG_FUNCTION_NEXT
3733                    | (int) ATTR_FLAG_ARRAY_NEXT))
3734         {
3735           *no_add_attrs = true;
3736           return tree_cons (name, args, NULL_TREE);
3737         }
3738       if (TREE_CODE (node) != RECORD_TYPE && TREE_CODE (node) != UNION_TYPE)
3739         {
3740           warning (OPT_Wattributes, "%qs attribute ignored",
3741                    IDENTIFIER_POINTER (name));
3742           *no_add_attrs = true;
3743         }
3744
3745       return NULL_TREE;
3746     }
3747
3748   if (TREE_CODE (node) != FUNCTION_DECL
3749       && TREE_CODE (node) != VAR_DECL)
3750     {
3751       *no_add_attrs = true;
3752       warning (OPT_Wattributes, "%qs attribute ignored",
3753                IDENTIFIER_POINTER (name));
3754       return NULL_TREE;
3755     }
3756
3757   /* Report error on dllimport ambiguities seen now before they cause
3758      any damage.  */
3759   else if (is_attribute_p ("dllimport", name))
3760     {
3761       /* Honor any target-specific overrides. */
3762       if (!targetm.valid_dllimport_attribute_p (node))
3763         *no_add_attrs = true;
3764
3765      else if (TREE_CODE (node) == FUNCTION_DECL
3766                 && DECL_DECLARED_INLINE_P (node))
3767         {
3768           warning (OPT_Wattributes, "inline function %q+D declared as "
3769                   " dllimport: attribute ignored", node);
3770           *no_add_attrs = true;
3771         }
3772       /* Like MS, treat definition of dllimported variables and
3773          non-inlined functions on declaration as syntax errors. */
3774      else if (TREE_CODE (node) == FUNCTION_DECL && DECL_INITIAL (node))
3775         {
3776           error ("function %q+D definition is marked dllimport", node);
3777           *no_add_attrs = true;
3778         }
3779
3780      else if (TREE_CODE (node) == VAR_DECL)
3781         {
3782           if (DECL_INITIAL (node))
3783             {
3784               error ("variable %q+D definition is marked dllimport",
3785                      node);
3786               *no_add_attrs = true;
3787             }
3788
3789           /* `extern' needn't be specified with dllimport.
3790              Specify `extern' now and hope for the best.  Sigh.  */
3791           DECL_EXTERNAL (node) = 1;
3792           /* Also, implicitly give dllimport'd variables declared within
3793              a function global scope, unless declared static.  */
3794           if (current_function_decl != NULL_TREE && !TREE_STATIC (node))
3795             TREE_PUBLIC (node) = 1;
3796         }
3797
3798       if (*no_add_attrs == false)
3799         DECL_DLLIMPORT_P (node) = 1;
3800     }
3801
3802   /*  Report error if symbol is not accessible at global scope.  */
3803   if (!TREE_PUBLIC (node)
3804       && (TREE_CODE (node) == VAR_DECL
3805           || TREE_CODE (node) == FUNCTION_DECL))
3806     {
3807       error ("external linkage required for symbol %q+D because of "
3808              "%qs attribute", node, IDENTIFIER_POINTER (name));
3809       *no_add_attrs = true;
3810     }
3811
3812   return NULL_TREE;
3813 }
3814
3815 #endif /* TARGET_DLLIMPORT_DECL_ATTRIBUTES  */
3816 \f
3817 /* Set the type qualifiers for TYPE to TYPE_QUALS, which is a bitmask
3818    of the various TYPE_QUAL values.  */
3819
3820 static void
3821 set_type_quals (tree type, int type_quals)
3822 {
3823   TYPE_READONLY (type) = (type_quals & TYPE_QUAL_CONST) != 0;
3824   TYPE_VOLATILE (type) = (type_quals & TYPE_QUAL_VOLATILE) != 0;
3825   TYPE_RESTRICT (type) = (type_quals & TYPE_QUAL_RESTRICT) != 0;
3826 }
3827
3828 /* Returns true iff cand is equivalent to base with type_quals.  */
3829
3830 bool
3831 check_qualified_type (tree cand, tree base, int type_quals)
3832 {
3833   return (TYPE_QUALS (cand) == type_quals
3834           && TYPE_NAME (cand) == TYPE_NAME (base)
3835           /* Apparently this is needed for Objective-C.  */
3836           && TYPE_CONTEXT (cand) == TYPE_CONTEXT (base)
3837           && attribute_list_equal (TYPE_ATTRIBUTES (cand),
3838                                    TYPE_ATTRIBUTES (base)));
3839 }
3840
3841 /* Return a version of the TYPE, qualified as indicated by the
3842    TYPE_QUALS, if one exists.  If no qualified version exists yet,
3843    return NULL_TREE.  */
3844
3845 tree
3846 get_qualified_type (tree type, int type_quals)
3847 {
3848   tree t;
3849
3850   if (TYPE_QUALS (type) == type_quals)
3851     return type;
3852
3853   /* Search the chain of variants to see if there is already one there just
3854      like the one we need to have.  If so, use that existing one.  We must
3855      preserve the TYPE_NAME, since there is code that depends on this.  */
3856   for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
3857     if (check_qualified_type (t, type, type_quals))
3858       return t;
3859
3860   return NULL_TREE;
3861 }
3862
3863 /* Like get_qualified_type, but creates the type if it does not
3864    exist.  This function never returns NULL_TREE.  */
3865
3866 tree
3867 build_qualified_type (tree type, int type_quals)
3868 {
3869   tree t;
3870
3871   /* See if we already have the appropriate qualified variant.  */
3872   t = get_qualified_type (type, type_quals);
3873
3874   /* If not, build it.  */
3875   if (!t)
3876     {
3877       t = build_variant_type_copy (type);
3878       set_type_quals (t, type_quals);
3879     }
3880
3881   return t;
3882 }
3883
3884 /* Create a new distinct copy of TYPE.  The new type is made its own
3885    MAIN_VARIANT.  */
3886
3887 tree
3888 build_distinct_type_copy (tree type)
3889 {
3890   tree t = copy_node (type);
3891
3892   TYPE_POINTER_TO (t) = 0;
3893   TYPE_REFERENCE_TO (t) = 0;
3894
3895   /* Make it its own variant.  */
3896   TYPE_MAIN_VARIANT (t) = t;
3897   TYPE_NEXT_VARIANT (t) = 0;
3898
3899   return t;
3900 }
3901
3902 /* Create a new variant of TYPE, equivalent but distinct.
3903    This is so the caller can modify it.  */
3904
3905 tree
3906 build_variant_type_copy (tree type)
3907 {
3908   tree t, m = TYPE_MAIN_VARIANT (type);
3909
3910   t = build_distinct_type_copy (type);
3911
3912   /* Add the new type to the chain of variants of TYPE.  */
3913   TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (m);
3914   TYPE_NEXT_VARIANT (m) = t;
3915   TYPE_MAIN_VARIANT (t) = m;
3916
3917   return t;
3918 }
3919 \f
3920 /* Return true if the from tree in both tree maps are equal.  */
3921
3922 int
3923 tree_map_eq (const void *va, const void *vb)
3924 {
3925   const struct tree_map  *a = va, *b = vb;
3926   return (a->from == b->from);
3927 }
3928
3929 /* Hash a from tree in a tree_map.  */
3930
3931 unsigned int
3932 tree_map_hash (const void *item)
3933 {
3934   return (((const struct tree_map *) item)->hash);
3935 }
3936
3937 /* Return true if this tree map structure is marked for garbage collection
3938    purposes.  We simply return true if the from tree is marked, so that this
3939    structure goes away when the from tree goes away.  */
3940
3941 int
3942 tree_map_marked_p (const void *p)
3943 {
3944   tree from = ((struct tree_map *) p)->from;
3945
3946   return ggc_marked_p (from);
3947 }
3948
3949 /* Return true if the trees in the tree_int_map *'s VA and VB are equal.  */
3950
3951 static int
3952 tree_int_map_eq (const void *va, const void *vb)
3953 {
3954   const struct tree_int_map  *a = va, *b = vb;
3955   return (a->from == b->from);
3956 }
3957
3958 /* Hash a from tree in the tree_int_map * ITEM.  */
3959
3960 static unsigned int
3961 tree_int_map_hash (const void *item)
3962 {
3963   return htab_hash_pointer (((const struct tree_int_map *)item)->from);
3964 }
3965
3966 /* Return true if this tree int map structure is marked for garbage collection
3967    purposes.  We simply return true if the from tree_int_map *P's from tree is marked, so that this
3968    structure goes away when the from tree goes away.  */
3969
3970 static int
3971 tree_int_map_marked_p (const void *p)
3972 {
3973   tree from = ((struct tree_int_map *) p)->from;
3974
3975   return ggc_marked_p (from);
3976 }
3977 /* Lookup an init priority for FROM, and return it if we find one.  */
3978
3979 unsigned short
3980 decl_init_priority_lookup (tree from)
3981 {
3982   struct tree_int_map *h, in;
3983   in.from = from;
3984
3985   h = htab_find_with_hash (init_priority_for_decl,
3986                            &in, htab_hash_pointer (from));
3987   if (h)
3988     return h->to;
3989   return 0;
3990 }
3991
3992 /* Insert a mapping FROM->TO in the init priority hashtable.  */
3993
3994 void
3995 decl_init_priority_insert (tree from, unsigned short to)
3996 {
3997   struct tree_int_map *h;
3998   void **loc;
3999
4000   h = ggc_alloc (sizeof (struct tree_int_map));
4001   h->from = from;
4002   h->to = to;
4003   loc = htab_find_slot_with_hash (init_priority_for_decl, h,
4004                                   htab_hash_pointer (from), INSERT);
4005   *(struct tree_int_map **) loc = h;
4006 }
4007
4008 /* Look up a restrict qualified base decl for FROM.  */
4009
4010 tree
4011 decl_restrict_base_lookup (tree from)
4012 {
4013   struct tree_map *h;
4014   struct tree_map in;
4015
4016   in.from = from;
4017   h = htab_find_with_hash (restrict_base_for_decl, &in,
4018                            htab_hash_pointer (from));
4019   return h ? h->to : NULL_TREE;
4020 }
4021
4022 /* Record the restrict qualified base TO for FROM.  */
4023
4024 void
4025 decl_restrict_base_insert (tree from, tree to)
4026 {
4027   struct tree_map *h;
4028   void **loc;
4029
4030   h = ggc_alloc (sizeof (struct tree_map));
4031   h->hash = htab_hash_pointer (from);
4032   h->from = from;
4033   h->to = to;
4034   loc = htab_find_slot_with_hash (restrict_base_for_decl, h, h->hash, INSERT);
4035   *(struct tree_map **) loc = h;
4036 }
4037
4038 /* Print out the statistics for the DECL_DEBUG_EXPR hash table.  */
4039
4040 static void
4041 print_debug_expr_statistics (void)
4042 {
4043   fprintf (stderr, "DECL_DEBUG_EXPR  hash: size %ld, %ld elements, %f collisions\n",
4044            (long) htab_size (debug_expr_for_decl),
4045            (long) htab_elements (debug_expr_for_decl),
4046            htab_collisions (debug_expr_for_decl));
4047 }
4048
4049 /* Print out the statistics for the DECL_VALUE_EXPR hash table.  */
4050
4051 static void
4052 print_value_expr_statistics (void)
4053 {
4054   fprintf (stderr, "DECL_VALUE_EXPR  hash: size %ld, %ld elements, %f collisions\n",
4055            (long) htab_size (value_expr_for_decl),
4056            (long) htab_elements (value_expr_for_decl),
4057            htab_collisions (value_expr_for_decl));
4058 }
4059
4060 /* Print out statistics for the RESTRICT_BASE_FOR_DECL hash table, but
4061    don't print anything if the table is empty.  */
4062
4063 static void
4064 print_restrict_base_statistics (void)
4065 {
4066   if (htab_elements (restrict_base_for_decl) != 0)
4067     fprintf (stderr,
4068              "RESTRICT_BASE    hash: size %ld, %ld elements, %f collisions\n",
4069              (long) htab_size (restrict_base_for_decl),
4070              (long) htab_elements (restrict_base_for_decl),
4071              htab_collisions (restrict_base_for_decl));
4072 }
4073
4074 /* Lookup a debug expression for FROM, and return it if we find one.  */
4075
4076 tree
4077 decl_debug_expr_lookup (tree from)
4078 {
4079   struct tree_map *h, in;
4080   in.from = from;
4081
4082   h = htab_find_with_hash (debug_expr_for_decl, &in, htab_hash_pointer (from));
4083   if (h)
4084     return h->to;
4085   return NULL_TREE;
4086 }
4087
4088 /* Insert a mapping FROM->TO in the debug expression hashtable.  */
4089
4090 void
4091 decl_debug_expr_insert (tree from, tree to)
4092 {
4093   struct tree_map *h;
4094   void **loc;
4095
4096   h = ggc_alloc (sizeof (struct tree_map));
4097   h->hash = htab_hash_pointer (from);
4098   h->from = from;
4099   h->to = to;
4100   loc = htab_find_slot_with_hash (debug_expr_for_decl, h, h->hash, INSERT);
4101   *(struct tree_map **) loc = h;
4102 }
4103
4104 /* Lookup a value expression for FROM, and return it if we find one.  */
4105
4106 tree
4107 decl_value_expr_lookup (tree from)
4108 {
4109   struct tree_map *h, in;
4110   in.from = from;
4111
4112   h = htab_find_with_hash (value_expr_for_decl, &in, htab_hash_pointer (from));
4113   if (h)
4114     return h->to;
4115   return NULL_TREE;
4116 }
4117
4118 /* Insert a mapping FROM->TO in the value expression hashtable.  */
4119
4120 void
4121 decl_value_expr_insert (tree from, tree to)
4122 {
4123   struct tree_map *h;
4124   void **loc;
4125
4126   h = ggc_alloc (sizeof (struct tree_map));
4127   h->hash = htab_hash_pointer (from);
4128   h->from = from;
4129   h->to = to;
4130   loc = htab_find_slot_with_hash (value_expr_for_decl, h, h->hash, INSERT);
4131   *(struct tree_map **) loc = h;
4132 }
4133
4134 /* Hashing of types so that we don't make duplicates.
4135    The entry point is `type_hash_canon'.  */
4136
4137 /* Compute a hash code for a list of types (chain of TREE_LIST nodes
4138    with types in the TREE_VALUE slots), by adding the hash codes
4139    of the individual types.  */
4140
4141 unsigned int
4142 type_hash_list (tree list, hashval_t hashcode)
4143 {
4144   tree tail;
4145
4146   for (tail = list; tail; tail = TREE_CHAIN (tail))
4147     if (TREE_VALUE (tail) != error_mark_node)
4148       hashcode = iterative_hash_object (TYPE_HASH (TREE_VALUE (tail)),
4149                                         hashcode);
4150
4151   return hashcode;
4152 }
4153
4154 /* These are the Hashtable callback functions.  */
4155
4156 /* Returns true iff the types are equivalent.  */
4157
4158 static int
4159 type_hash_eq (const void *va, const void *vb)
4160 {
4161   const struct type_hash *a = va, *b = vb;
4162
4163   /* First test the things that are the same for all types.  */
4164   if (a->hash != b->hash
4165       || TREE_CODE (a->type) != TREE_CODE (b->type)
4166       || TREE_TYPE (a->type) != TREE_TYPE (b->type)
4167       || !attribute_list_equal (TYPE_ATTRIBUTES (a->type),
4168                                  TYPE_ATTRIBUTES (b->type))
4169       || TYPE_ALIGN (a->type) != TYPE_ALIGN (b->type)
4170       || TYPE_MODE (a->type) != TYPE_MODE (b->type))
4171     return 0;
4172
4173   switch (TREE_CODE (a->type))
4174     {
4175     case VOID_TYPE:
4176     case COMPLEX_TYPE:
4177     case POINTER_TYPE:
4178     case REFERENCE_TYPE:
4179       return 1;
4180
4181     case VECTOR_TYPE:
4182       return TYPE_VECTOR_SUBPARTS (a->type) == TYPE_VECTOR_SUBPARTS (b->type);
4183
4184     case ENUMERAL_TYPE:
4185       if (TYPE_VALUES (a->type) != TYPE_VALUES (b->type)
4186           && !(TYPE_VALUES (a->type)
4187                && TREE_CODE (TYPE_VALUES (a->type)) == TREE_LIST
4188                && TYPE_VALUES (b->type)
4189                && TREE_CODE (TYPE_VALUES (b->type)) == TREE_LIST
4190                && type_list_equal (TYPE_VALUES (a->type),
4191                                    TYPE_VALUES (b->type))))
4192         return 0;
4193
4194       /* ... fall through ... */
4195
4196     case INTEGER_TYPE:
4197     case REAL_TYPE:
4198     case BOOLEAN_TYPE:
4199       return ((TYPE_MAX_VALUE (a->type) == TYPE_MAX_VALUE (b->type)
4200                || tree_int_cst_equal (TYPE_MAX_VALUE (a->type),
4201                                       TYPE_MAX_VALUE (b->type)))
4202               && (TYPE_MIN_VALUE (a->type) == TYPE_MIN_VALUE (b->type)
4203                   || tree_int_cst_equal (TYPE_MIN_VALUE (a->type),
4204                                          TYPE_MIN_VALUE (b->type))));
4205
4206     case OFFSET_TYPE:
4207       return TYPE_OFFSET_BASETYPE (a->type) == TYPE_OFFSET_BASETYPE (b->type);
4208
4209     case METHOD_TYPE:
4210       return (TYPE_METHOD_BASETYPE (a->type) == TYPE_METHOD_BASETYPE (b->type)
4211               && (TYPE_ARG_TYPES (a->type) == TYPE_ARG_TYPES (b->type)
4212                   || (TYPE_ARG_TYPES (a->type)
4213                       && TREE_CODE (TYPE_ARG_TYPES (a->type)) == TREE_LIST
4214                       && TYPE_ARG_TYPES (b->type)
4215                       && TREE_CODE (TYPE_ARG_TYPES (b->type)) == TREE_LIST
4216                       && type_list_equal (TYPE_ARG_TYPES (a->type),
4217                                           TYPE_ARG_TYPES (b->type)))));
4218
4219     case ARRAY_TYPE:
4220       return TYPE_DOMAIN (a->type) == TYPE_DOMAIN (b->type);
4221
4222     case RECORD_TYPE:
4223     case UNION_TYPE:
4224     case QUAL_UNION_TYPE:
4225       return (TYPE_FIELDS (a->type) == TYPE_FIELDS (b->type)
4226               || (TYPE_FIELDS (a->type)
4227                   && TREE_CODE (TYPE_FIELDS (a->type)) == TREE_LIST
4228                   && TYPE_FIELDS (b->type)
4229                   && TREE_CODE (TYPE_FIELDS (b->type)) == TREE_LIST
4230                   && type_list_equal (TYPE_FIELDS (a->type),
4231                                       TYPE_FIELDS (b->type))));
4232
4233     case FUNCTION_TYPE:
4234       return (TYPE_ARG_TYPES (a->type) == TYPE_ARG_TYPES (b->type)
4235               || (TYPE_ARG_TYPES (a->type)
4236                   && TREE_CODE (TYPE_ARG_TYPES (a->type)) == TREE_LIST
4237                   && TYPE_ARG_TYPES (b->type)
4238                   && TREE_CODE (TYPE_ARG_TYPES (b->type)) == TREE_LIST
4239                   && type_list_equal (TYPE_ARG_TYPES (a->type),
4240                                       TYPE_ARG_TYPES (b->type))));
4241
4242     default:
4243       return 0;
4244     }
4245 }
4246
4247 /* Return the cached hash value.  */
4248
4249 static hashval_t
4250 type_hash_hash (const void *item)
4251 {
4252   return ((const struct type_hash *) item)->hash;
4253 }
4254
4255 /* Look in the type hash table for a type isomorphic to TYPE.
4256    If one is found, return it.  Otherwise return 0.  */
4257
4258 tree
4259 type_hash_lookup (hashval_t hashcode, tree type)
4260 {
4261   struct type_hash *h, in;
4262
4263   /* The TYPE_ALIGN field of a type is set by layout_type(), so we
4264      must call that routine before comparing TYPE_ALIGNs.  */
4265   layout_type (type);
4266
4267   in.hash = hashcode;
4268   in.type = type;
4269
4270   h = htab_find_with_hash (type_hash_table, &in, hashcode);
4271   if (h)
4272     return h->type;
4273   return NULL_TREE;
4274 }
4275
4276 /* Add an entry to the type-hash-table
4277    for a type TYPE whose hash code is HASHCODE.  */
4278
4279 void
4280 type_hash_add (hashval_t hashcode, tree type)
4281 {
4282   struct type_hash *h;
4283   void **loc;
4284
4285   h = ggc_alloc (sizeof (struct type_hash));
4286   h->hash = hashcode;
4287   h->type = type;
4288   loc = htab_find_slot_with_hash (type_hash_table, h, hashcode, INSERT);
4289   *(struct type_hash **) loc = h;
4290 }
4291
4292 /* Given TYPE, and HASHCODE its hash code, return the canonical
4293    object for an identical type if one already exists.
4294    Otherwise, return TYPE, and record it as the canonical object.
4295
4296    To use this function, first create a type of the sort you want.
4297    Then compute its hash code from the fields of the type that
4298    make it different from other similar types.
4299    Then call this function and use the value.  */
4300
4301 tree
4302 type_hash_canon (unsigned int hashcode, tree type)
4303 {
4304   tree t1;
4305
4306   /* The hash table only contains main variants, so ensure that's what we're
4307      being passed.  */
4308   gcc_assert (TYPE_MAIN_VARIANT (type) == type);
4309
4310   if (!lang_hooks.types.hash_types)
4311     return type;
4312
4313   /* See if the type is in the hash table already.  If so, return it.
4314      Otherwise, add the type.  */
4315   t1 = type_hash_lookup (hashcode, type);
4316   if (t1 != 0)
4317     {
4318 #ifdef GATHER_STATISTICS
4319       tree_node_counts[(int) t_kind]--;
4320       tree_node_sizes[(int) t_kind] -= sizeof (struct tree_type);
4321 #endif
4322       return t1;
4323     }
4324   else
4325     {
4326       type_hash_add (hashcode, type);
4327       return type;
4328     }
4329 }
4330
4331 /* See if the data pointed to by the type hash table is marked.  We consider
4332    it marked if the type is marked or if a debug type number or symbol
4333    table entry has been made for the type.  This reduces the amount of
4334    debugging output and eliminates that dependency of the debug output on
4335    the number of garbage collections.  */
4336
4337 static int
4338 type_hash_marked_p (const void *p)
4339 {
4340   tree type = ((struct type_hash *) p)->type;
4341
4342   return ggc_marked_p (type) || TYPE_SYMTAB_POINTER (type);
4343 }
4344
4345 static void
4346 print_type_hash_statistics (void)
4347 {
4348   fprintf (stderr, "Type hash: size %ld, %ld elements, %f collisions\n",
4349            (long) htab_size (type_hash_table),
4350            (long) htab_elements (type_hash_table),
4351            htab_collisions (type_hash_table));
4352 }
4353
4354 /* Compute a hash code for a list of attributes (chain of TREE_LIST nodes
4355    with names in the TREE_PURPOSE slots and args in the TREE_VALUE slots),
4356    by adding the hash codes of the individual attributes.  */
4357
4358 unsigned int
4359 attribute_hash_list (tree list, hashval_t hashcode)
4360 {
4361   tree tail;
4362
4363   for (tail = list; tail; tail = TREE_CHAIN (tail))
4364     /* ??? Do we want to add in TREE_VALUE too? */
4365     hashcode = iterative_hash_object
4366       (IDENTIFIER_HASH_VALUE (TREE_PURPOSE (tail)), hashcode);
4367   return hashcode;
4368 }
4369
4370 /* Given two lists of attributes, return true if list l2 is
4371    equivalent to l1.  */
4372
4373 int
4374 attribute_list_equal (tree l1, tree l2)
4375 {
4376   return attribute_list_contained (l1, l2)
4377          && attribute_list_contained (l2, l1);
4378 }
4379
4380 /* Given two lists of attributes, return true if list L2 is
4381    completely contained within L1.  */
4382 /* ??? This would be faster if attribute names were stored in a canonicalized
4383    form.  Otherwise, if L1 uses `foo' and L2 uses `__foo__', the long method
4384    must be used to show these elements are equivalent (which they are).  */
4385 /* ??? It's not clear that attributes with arguments will always be handled
4386    correctly.  */
4387
4388 int
4389 attribute_list_contained (tree l1, tree l2)
4390 {
4391   tree t1, t2;
4392
4393   /* First check the obvious, maybe the lists are identical.  */
4394   if (l1 == l2)
4395     return 1;
4396
4397   /* Maybe the lists are similar.  */
4398   for (t1 = l1, t2 = l2;
4399        t1 != 0 && t2 != 0
4400         && TREE_PURPOSE (t1) == TREE_PURPOSE (t2)
4401         && TREE_VALUE (t1) == TREE_VALUE (t2);
4402        t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2));
4403
4404   /* Maybe the lists are equal.  */
4405   if (t1 == 0 && t2 == 0)
4406     return 1;
4407
4408   for (; t2 != 0; t2 = TREE_CHAIN (t2))
4409     {
4410       tree attr;
4411       for (attr = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (t2)), l1);
4412            attr != NULL_TREE;
4413            attr = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (t2)),
4414                                     TREE_CHAIN (attr)))
4415         {
4416           if (TREE_VALUE (t2) != NULL
4417               && TREE_CODE (TREE_VALUE (t2)) == TREE_LIST
4418               && TREE_VALUE (attr) != NULL
4419               && TREE_CODE (TREE_VALUE (attr)) == TREE_LIST)
4420             {
4421               if (simple_cst_list_equal (TREE_VALUE (t2),
4422                                          TREE_VALUE (attr)) == 1)
4423                 break;
4424             }
4425           else if (simple_cst_equal (TREE_VALUE (t2), TREE_VALUE (attr)) == 1)
4426             break;
4427         }
4428
4429       if (attr == 0)
4430         return 0;
4431     }
4432
4433   return 1;
4434 }
4435
4436 /* Given two lists of types
4437    (chains of TREE_LIST nodes with types in the TREE_VALUE slots)
4438    return 1 if the lists contain the same types in the same order.
4439    Also, the TREE_PURPOSEs must match.  */
4440
4441 int
4442 type_list_equal (tree l1, tree l2)
4443 {
4444   tree t1, t2;
4445
4446   for (t1 = l1, t2 = l2; t1 && t2; t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2))
4447     if (TREE_VALUE (t1) != TREE_VALUE (t2)
4448         || (TREE_PURPOSE (t1) != TREE_PURPOSE (t2)
4449             && ! (1 == simple_cst_equal (TREE_PURPOSE (t1), TREE_PURPOSE (t2))
4450                   && (TREE_TYPE (TREE_PURPOSE (t1))
4451                       == TREE_TYPE (TREE_PURPOSE (t2))))))
4452       return 0;
4453
4454   return t1 == t2;
4455 }
4456
4457 /* Returns the number of arguments to the FUNCTION_TYPE or METHOD_TYPE
4458    given by TYPE.  If the argument list accepts variable arguments,
4459    then this function counts only the ordinary arguments.  */
4460
4461 int
4462 type_num_arguments (tree type)
4463 {
4464   int i = 0;
4465   tree t;
4466
4467   for (t = TYPE_ARG_TYPES (type); t; t = TREE_CHAIN (t))
4468     /* If the function does not take a variable number of arguments,
4469        the last element in the list will have type `void'.  */
4470     if (VOID_TYPE_P (TREE_VALUE (t)))
4471       break;
4472     else
4473       ++i;
4474
4475   return i;
4476 }
4477
4478 /* Nonzero if integer constants T1 and T2
4479    represent the same constant value.  */
4480
4481 int
4482 tree_int_cst_equal (tree t1, tree t2)
4483 {
4484   if (t1 == t2)
4485     return 1;
4486
4487   if (t1 == 0 || t2 == 0)
4488     return 0;
4489
4490   if (TREE_CODE (t1) == INTEGER_CST
4491       && TREE_CODE (t2) == INTEGER_CST
4492       && TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
4493       && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2))
4494     return 1;
4495
4496   return 0;
4497 }
4498
4499 /* Nonzero if integer constants T1 and T2 represent values that satisfy <.
4500    The precise way of comparison depends on their data type.  */
4501
4502 int
4503 tree_int_cst_lt (tree t1, tree t2)
4504 {
4505   if (t1 == t2)
4506     return 0;
4507
4508   if (TYPE_UNSIGNED (TREE_TYPE (t1)) != TYPE_UNSIGNED (TREE_TYPE (t2)))
4509     {
4510       int t1_sgn = tree_int_cst_sgn (t1);
4511       int t2_sgn = tree_int_cst_sgn (t2);
4512
4513       if (t1_sgn < t2_sgn)
4514         return 1;
4515       else if (t1_sgn > t2_sgn)
4516         return 0;
4517       /* Otherwise, both are non-negative, so we compare them as
4518          unsigned just in case one of them would overflow a signed
4519          type.  */
4520     }
4521   else if (!TYPE_UNSIGNED (TREE_TYPE (t1)))
4522     return INT_CST_LT (t1, t2);
4523
4524   return INT_CST_LT_UNSIGNED (t1, t2);
4525 }
4526
4527 /* Returns -1 if T1 < T2, 0 if T1 == T2, and 1 if T1 > T2.  */
4528
4529 int
4530 tree_int_cst_compare (tree t1, tree t2)
4531 {
4532   if (tree_int_cst_lt (t1, t2))
4533     return -1;
4534   else if (tree_int_cst_lt (t2, t1))
4535     return 1;
4536   else
4537     return 0;
4538 }
4539
4540 /* Return 1 if T is an INTEGER_CST that can be manipulated efficiently on
4541    the host.  If POS is zero, the value can be represented in a single
4542    HOST_WIDE_INT.  If POS is nonzero, the value must be non-negative and can
4543    be represented in a single unsigned HOST_WIDE_INT.  */
4544
4545 int
4546 host_integerp (tree t, int pos)
4547 {
4548   return (TREE_CODE (t) == INTEGER_CST
4549           && ((TREE_INT_CST_HIGH (t) == 0
4550                && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) >= 0)
4551               || (! pos && TREE_INT_CST_HIGH (t) == -1
4552                   && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0
4553                   && !TYPE_UNSIGNED (TREE_TYPE (t)))
4554               || (pos && TREE_INT_CST_HIGH (t) == 0)));
4555 }
4556
4557 /* Return the HOST_WIDE_INT least significant bits of T if it is an
4558    INTEGER_CST and there is no overflow.  POS is nonzero if the result must
4559    be non-negative.  We must be able to satisfy the above conditions.  */
4560
4561 HOST_WIDE_INT
4562 tree_low_cst (tree t, int pos)
4563 {
4564   gcc_assert (host_integerp (t, pos));
4565   return TREE_INT_CST_LOW (t);
4566 }
4567
4568 /* Return the most significant bit of the integer constant T.  */
4569
4570 int
4571 tree_int_cst_msb (tree t)
4572 {
4573   int prec;
4574   HOST_WIDE_INT h;
4575   unsigned HOST_WIDE_INT l;
4576
4577   /* Note that using TYPE_PRECISION here is wrong.  We care about the
4578      actual bits, not the (arbitrary) range of the type.  */
4579   prec = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (t))) - 1;
4580   rshift_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t), prec,
4581                  2 * HOST_BITS_PER_WIDE_INT, &l, &h, 0);
4582   return (l & 1) == 1;
4583 }
4584
4585 /* Return an indication of the sign of the integer constant T.
4586    The return value is -1 if T < 0, 0 if T == 0, and 1 if T > 0.
4587    Note that -1 will never be returned if T's type is unsigned.  */
4588
4589 int
4590 tree_int_cst_sgn (tree t)
4591 {
4592   if (TREE_INT_CST_LOW (t) == 0 && TREE_INT_CST_HIGH (t) == 0)
4593     return 0;
4594   else if (TYPE_UNSIGNED (TREE_TYPE (t)))
4595     return 1;
4596   else if (TREE_INT_CST_HIGH (t) < 0)
4597     return -1;
4598   else
4599     return 1;
4600 }
4601
4602 /* Compare two constructor-element-type constants.  Return 1 if the lists
4603    are known to be equal; otherwise return 0.  */
4604
4605 int
4606 simple_cst_list_equal (tree l1, tree l2)
4607 {
4608   while (l1 != NULL_TREE && l2 != NULL_TREE)
4609     {
4610       if (simple_cst_equal (TREE_VALUE (l1), TREE_VALUE (l2)) != 1)
4611         return 0;
4612
4613       l1 = TREE_CHAIN (l1);
4614       l2 = TREE_CHAIN (l2);
4615     }
4616
4617   return l1 == l2;
4618 }
4619
4620 /* Return truthvalue of whether T1 is the same tree structure as T2.
4621    Return 1 if they are the same.
4622    Return 0 if they are understandably different.
4623    Return -1 if either contains tree structure not understood by
4624    this function.  */
4625
4626 int
4627 simple_cst_equal (tree t1, tree t2)
4628 {
4629   enum tree_code code1, code2;
4630   int cmp;
4631   int i;
4632
4633   if (t1 == t2)
4634     return 1;
4635   if (t1 == 0 || t2 == 0)
4636     return 0;
4637
4638   code1 = TREE_CODE (t1);
4639   code2 = TREE_CODE (t2);
4640
4641   if (code1 == NOP_EXPR || code1 == CONVERT_EXPR || code1 == NON_LVALUE_EXPR)
4642     {
4643       if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
4644           || code2 == NON_LVALUE_EXPR)
4645         return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4646       else
4647         return simple_cst_equal (TREE_OPERAND (t1, 0), t2);
4648     }
4649
4650   else if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
4651            || code2 == NON_LVALUE_EXPR)
4652     return simple_cst_equal (t1, TREE_OPERAND (t2, 0));
4653
4654   if (code1 != code2)
4655     return 0;
4656
4657   switch (code1)
4658     {
4659     case INTEGER_CST:
4660       return (TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
4661               && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2));
4662
4663     case REAL_CST:
4664       return REAL_VALUES_IDENTICAL (TREE_REAL_CST (t1), TREE_REAL_CST (t2));
4665
4666     case STRING_CST:
4667       return (TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
4668               && ! memcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2),
4669                          TREE_STRING_LENGTH (t1)));
4670
4671     case CONSTRUCTOR:
4672       {
4673         unsigned HOST_WIDE_INT idx;
4674         VEC(constructor_elt, gc) *v1 = CONSTRUCTOR_ELTS (t1);
4675         VEC(constructor_elt, gc) *v2 = CONSTRUCTOR_ELTS (t2);
4676
4677         if (VEC_length (constructor_elt, v1) != VEC_length (constructor_elt, v2))
4678           return false;
4679
4680         for (idx = 0; idx < VEC_length (constructor_elt, v1); ++idx)
4681           /* ??? Should we handle also fields here? */
4682           if (!simple_cst_equal (VEC_index (constructor_elt, v1, idx)->value,
4683                                  VEC_index (constructor_elt, v2, idx)->value))
4684             return false;
4685         return true;
4686       }
4687
4688     case SAVE_EXPR:
4689       return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4690
4691     case CALL_EXPR:
4692       cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4693       if (cmp <= 0)
4694         return cmp;
4695       return
4696         simple_cst_list_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
4697
4698     case TARGET_EXPR:
4699       /* Special case: if either target is an unallocated VAR_DECL,
4700          it means that it's going to be unified with whatever the
4701          TARGET_EXPR is really supposed to initialize, so treat it
4702          as being equivalent to anything.  */
4703       if ((TREE_CODE (TREE_OPERAND (t1, 0)) == VAR_DECL
4704            && DECL_NAME (TREE_OPERAND (t1, 0)) == NULL_TREE
4705            && !DECL_RTL_SET_P (TREE_OPERAND (t1, 0)))
4706           || (TREE_CODE (TREE_OPERAND (t2, 0)) == VAR_DECL
4707               && DECL_NAME (TREE_OPERAND (t2, 0)) == NULL_TREE
4708               && !DECL_RTL_SET_P (TREE_OPERAND (t2, 0))))
4709         cmp = 1;
4710       else
4711         cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4712
4713       if (cmp <= 0)
4714         return cmp;
4715
4716       return simple_cst_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
4717
4718     case WITH_CLEANUP_EXPR:
4719       cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4720       if (cmp <= 0)
4721         return cmp;
4722
4723       return simple_cst_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t1, 1));
4724
4725     case COMPONENT_REF:
4726       if (TREE_OPERAND (t1, 1) == TREE_OPERAND (t2, 1))
4727         return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4728
4729       return 0;
4730
4731     case VAR_DECL:
4732     case PARM_DECL:
4733     case CONST_DECL:
4734     case FUNCTION_DECL:
4735       return 0;
4736
4737     default:
4738       break;
4739     }
4740
4741   /* This general rule works for most tree codes.  All exceptions should be
4742      handled above.  If this is a language-specific tree code, we can't
4743      trust what might be in the operand, so say we don't know
4744      the situation.  */
4745   if ((int) code1 >= (int) LAST_AND_UNUSED_TREE_CODE)
4746     return -1;
4747
4748   switch (TREE_CODE_CLASS (code1))
4749     {
4750     case tcc_unary:
4751     case tcc_binary:
4752     case tcc_comparison:
4753     case tcc_expression:
4754     case tcc_reference:
4755     case tcc_statement:
4756       cmp = 1;
4757       for (i = 0; i < TREE_CODE_LENGTH (code1); i++)
4758         {
4759           cmp = simple_cst_equal (TREE_OPERAND (t1, i), TREE_OPERAND (t2, i));
4760           if (cmp <= 0)
4761             return cmp;
4762         }
4763
4764       return cmp;
4765
4766     default:
4767       return -1;
4768     }
4769 }
4770
4771 /* Compare the value of T, an INTEGER_CST, with U, an unsigned integer value.
4772    Return -1, 0, or 1 if the value of T is less than, equal to, or greater
4773    than U, respectively.  */
4774
4775 int
4776 compare_tree_int (tree t, unsigned HOST_WIDE_INT u)
4777 {
4778   if (tree_int_cst_sgn (t) < 0)
4779     return -1;
4780   else if (TREE_INT_CST_HIGH (t) != 0)
4781     return 1;
4782   else if (TREE_INT_CST_LOW (t) == u)
4783     return 0;
4784   else if (TREE_INT_CST_LOW (t) < u)
4785     return -1;
4786   else
4787     return 1;
4788 }
4789
4790 /* Return true if CODE represents an associative tree code.  Otherwise
4791    return false.  */
4792 bool
4793 associative_tree_code (enum tree_code code)
4794 {
4795   switch (code)
4796     {
4797     case BIT_IOR_EXPR:
4798     case BIT_AND_EXPR:
4799     case BIT_XOR_EXPR:
4800     case PLUS_EXPR:
4801     case MULT_EXPR:
4802     case MIN_EXPR:
4803     case MAX_EXPR:
4804       return true;
4805
4806     default:
4807       break;
4808     }
4809   return false;
4810 }
4811
4812 /* Return true if CODE represents a commutative tree code.  Otherwise
4813    return false.  */
4814 bool
4815 commutative_tree_code (enum tree_code code)
4816 {
4817   switch (code)
4818     {
4819     case PLUS_EXPR:
4820     case MULT_EXPR:
4821     case MIN_EXPR:
4822     case MAX_EXPR:
4823     case BIT_IOR_EXPR:
4824     case BIT_XOR_EXPR:
4825     case BIT_AND_EXPR:
4826     case NE_EXPR:
4827     case EQ_EXPR:
4828     case UNORDERED_EXPR:
4829     case ORDERED_EXPR:
4830     case UNEQ_EXPR:
4831     case LTGT_EXPR:
4832     case TRUTH_AND_EXPR:
4833     case TRUTH_XOR_EXPR:
4834     case TRUTH_OR_EXPR:
4835       return true;
4836
4837     default:
4838       break;
4839     }
4840   return false;
4841 }
4842
4843 /* Generate a hash value for an expression.  This can be used iteratively
4844    by passing a previous result as the "val" argument.
4845
4846    This function is intended to produce the same hash for expressions which
4847    would compare equal using operand_equal_p.  */
4848
4849 hashval_t
4850 iterative_hash_expr (tree t, hashval_t val)
4851 {
4852   int i;
4853   enum tree_code code;
4854   char class;
4855
4856   if (t == NULL_TREE)
4857     return iterative_hash_pointer (t, val);
4858
4859   code = TREE_CODE (t);
4860
4861   switch (code)
4862     {
4863     /* Alas, constants aren't shared, so we can't rely on pointer
4864        identity.  */
4865     case INTEGER_CST:
4866       val = iterative_hash_host_wide_int (TREE_INT_CST_LOW (t), val);
4867       return iterative_hash_host_wide_int (TREE_INT_CST_HIGH (t), val);
4868     case REAL_CST:
4869       {
4870         unsigned int val2 = real_hash (TREE_REAL_CST_PTR (t));
4871
4872         return iterative_hash_hashval_t (val2, val);
4873       }
4874     case STRING_CST:
4875       return iterative_hash (TREE_STRING_POINTER (t),
4876                              TREE_STRING_LENGTH (t), val);
4877     case COMPLEX_CST:
4878       val = iterative_hash_expr (TREE_REALPART (t), val);
4879       return iterative_hash_expr (TREE_IMAGPART (t), val);
4880     case VECTOR_CST:
4881       return iterative_hash_expr (TREE_VECTOR_CST_ELTS (t), val);
4882
4883     case SSA_NAME:
4884     case VALUE_HANDLE:
4885       /* we can just compare by pointer.  */
4886       return iterative_hash_pointer (t, val);
4887
4888     case TREE_LIST:
4889       /* A list of expressions, for a CALL_EXPR or as the elements of a
4890          VECTOR_CST.  */
4891       for (; t; t = TREE_CHAIN (t))
4892         val = iterative_hash_expr (TREE_VALUE (t), val);
4893       return val;
4894     case CONSTRUCTOR:
4895       {
4896         unsigned HOST_WIDE_INT idx;
4897         tree field, value;
4898         FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), idx, field, value)
4899           {
4900             val = iterative_hash_expr (field, val);
4901             val = iterative_hash_expr (value, val);
4902           }
4903         return val;
4904       }
4905     case FUNCTION_DECL:
4906       /* When referring to a built-in FUNCTION_DECL, use the
4907          __builtin__ form.  Otherwise nodes that compare equal
4908          according to operand_equal_p might get different
4909          hash codes.  */
4910       if (DECL_BUILT_IN (t))
4911         {
4912           val = iterative_hash_pointer (built_in_decls[DECL_FUNCTION_CODE (t)],
4913                                       val);
4914           return val;
4915         }
4916       /* else FALL THROUGH */
4917     default:
4918       class = TREE_CODE_CLASS (code);
4919
4920       if (class == tcc_declaration)
4921         {
4922           /* DECL's have a unique ID */
4923           val = iterative_hash_host_wide_int (DECL_UID (t), val);
4924         }
4925       else
4926         {
4927           gcc_assert (IS_EXPR_CODE_CLASS (class));
4928
4929           val = iterative_hash_object (code, val);
4930
4931           /* Don't hash the type, that can lead to having nodes which
4932              compare equal according to operand_equal_p, but which
4933              have different hash codes.  */
4934           if (code == NOP_EXPR
4935               || code == CONVERT_EXPR
4936               || code == NON_LVALUE_EXPR)
4937             {
4938               /* Make sure to include signness in the hash computation.  */
4939               val += TYPE_UNSIGNED (TREE_TYPE (t));
4940               val = iterative_hash_expr (TREE_OPERAND (t, 0), val);
4941             }
4942
4943           else if (commutative_tree_code (code))
4944             {
4945               /* It's a commutative expression.  We want to hash it the same
4946                  however it appears.  We do this by first hashing both operands
4947                  and then rehashing based on the order of their independent
4948                  hashes.  */
4949               hashval_t one = iterative_hash_expr (TREE_OPERAND (t, 0), 0);
4950               hashval_t two = iterative_hash_expr (TREE_OPERAND (t, 1), 0);
4951               hashval_t t;
4952
4953               if (one > two)
4954                 t = one, one = two, two = t;
4955
4956               val = iterative_hash_hashval_t (one, val);
4957               val = iterative_hash_hashval_t (two, val);
4958             }
4959           else
4960             for (i = TREE_CODE_LENGTH (code) - 1; i >= 0; --i)
4961               val = iterative_hash_expr (TREE_OPERAND (t, i), val);
4962         }
4963       return val;
4964       break;
4965     }
4966 }
4967 \f
4968 /* Constructors for pointer, array and function types.
4969    (RECORD_TYPE, UNION_TYPE and ENUMERAL_TYPE nodes are
4970    constructed by language-dependent code, not here.)  */
4971
4972 /* Construct, lay out and return the type of pointers to TO_TYPE with
4973    mode MODE.  If CAN_ALIAS_ALL is TRUE, indicate this type can
4974    reference all of memory. If such a type has already been
4975    constructed, reuse it.  */
4976
4977 tree
4978 build_pointer_type_for_mode (tree to_type, enum machine_mode mode,
4979                              bool can_alias_all)
4980 {
4981   tree t;
4982
4983   if (to_type == error_mark_node)
4984     return error_mark_node;
4985
4986   /* In some cases, languages will have things that aren't a POINTER_TYPE
4987      (such as a RECORD_TYPE for fat pointers in Ada) as TYPE_POINTER_TO.
4988      In that case, return that type without regard to the rest of our
4989      operands.
4990
4991      ??? This is a kludge, but consistent with the way this function has
4992      always operated and there doesn't seem to be a good way to avoid this
4993      at the moment.  */
4994   if (TYPE_POINTER_TO (to_type) != 0
4995       && TREE_CODE (TYPE_POINTER_TO (to_type)) != POINTER_TYPE)
4996     return TYPE_POINTER_TO (to_type);
4997
4998   /* First, if we already have a type for pointers to TO_TYPE and it's
4999      the proper mode, use it.  */
5000   for (t = TYPE_POINTER_TO (to_type); t; t = TYPE_NEXT_PTR_TO (t))
5001     if (TYPE_MODE (t) == mode && TYPE_REF_CAN_ALIAS_ALL (t) == can_alias_all)
5002       return t;
5003
5004   t = make_node (POINTER_TYPE);
5005
5006   TREE_TYPE (t) = to_type;
5007   TYPE_MODE (t) = mode;
5008   TYPE_REF_CAN_ALIAS_ALL (t) = can_alias_all;
5009   TYPE_NEXT_PTR_TO (t) = TYPE_POINTER_TO (to_type);
5010   TYPE_POINTER_TO (to_type) = t;
5011
5012   /* Lay out the type.  This function has many callers that are concerned
5013      with expression-construction, and this simplifies them all.  */
5014   layout_type (t);
5015
5016   return t;
5017 }
5018
5019 /* By default build pointers in ptr_mode.  */
5020
5021 tree
5022 build_pointer_type (tree to_type)
5023 {
5024   return build_pointer_type_for_mode (to_type, ptr_mode, false);
5025 }
5026
5027 /* Same as build_pointer_type_for_mode, but for REFERENCE_TYPE.  */
5028
5029 tree
5030 build_reference_type_for_mode (tree to_type, enum machine_mode mode,
5031                                bool can_alias_all)
5032 {
5033   tree t;
5034
5035   /* In some cases, languages will have things that aren't a REFERENCE_TYPE
5036      (such as a RECORD_TYPE for fat pointers in Ada) as TYPE_REFERENCE_TO.
5037      In that case, return that type without regard to the rest of our
5038      operands.
5039
5040      ??? This is a kludge, but consistent with the way this function has
5041      always operated and there doesn't seem to be a good way to avoid this
5042      at the moment.  */
5043   if (TYPE_REFERENCE_TO (to_type) != 0
5044       && TREE_CODE (TYPE_REFERENCE_TO (to_type)) != REFERENCE_TYPE)
5045     return TYPE_REFERENCE_TO (to_type);
5046
5047   /* First, if we already have a type for pointers to TO_TYPE and it's
5048      the proper mode, use it.  */
5049   for (t = TYPE_REFERENCE_TO (to_type); t; t = TYPE_NEXT_REF_TO (t))
5050     if (TYPE_MODE (t) == mode && TYPE_REF_CAN_ALIAS_ALL (t) == can_alias_all)
5051       return t;
5052
5053   t = make_node (REFERENCE_TYPE);
5054
5055   TREE_TYPE (t) = to_type;
5056   TYPE_MODE (t) = mode;
5057   TYPE_REF_CAN_ALIAS_ALL (t) = can_alias_all;
5058   TYPE_NEXT_REF_TO (t) = TYPE_REFERENCE_TO (to_type);
5059   TYPE_REFERENCE_TO (to_type) = t;
5060
5061   layout_type (t);
5062
5063   return t;
5064 }
5065
5066
5067 /* Build the node for the type of references-to-TO_TYPE by default
5068    in ptr_mode.  */
5069
5070 tree
5071 build_reference_type (tree to_type)
5072 {
5073   return build_reference_type_for_mode (to_type, ptr_mode, false);
5074 }
5075
5076 /* Build a type that is compatible with t but has no cv quals anywhere
5077    in its type, thus
5078
5079    const char *const *const *  ->  char ***.  */
5080
5081 tree
5082 build_type_no_quals (tree t)
5083 {
5084   switch (TREE_CODE (t))
5085     {
5086     case POINTER_TYPE:
5087       return build_pointer_type_for_mode (build_type_no_quals (TREE_TYPE (t)),
5088                                           TYPE_MODE (t),
5089                                           TYPE_REF_CAN_ALIAS_ALL (t));
5090     case REFERENCE_TYPE:
5091       return
5092         build_reference_type_for_mode (build_type_no_quals (TREE_TYPE (t)),
5093                                        TYPE_MODE (t),
5094                                        TYPE_REF_CAN_ALIAS_ALL (t));
5095     default:
5096       return TYPE_MAIN_VARIANT (t);
5097     }
5098 }
5099
5100 /* Create a type of integers to be the TYPE_DOMAIN of an ARRAY_TYPE.
5101    MAXVAL should be the maximum value in the domain
5102    (one less than the length of the array).
5103
5104    The maximum value that MAXVAL can have is INT_MAX for a HOST_WIDE_INT.
5105    We don't enforce this limit, that is up to caller (e.g. language front end).
5106    The limit exists because the result is a signed type and we don't handle
5107    sizes that use more than one HOST_WIDE_INT.  */
5108
5109 tree
5110 build_index_type (tree maxval)
5111 {
5112   tree itype = make_node (INTEGER_TYPE);
5113
5114   TREE_TYPE (itype) = sizetype;
5115   TYPE_PRECISION (itype) = TYPE_PRECISION (sizetype);
5116   TYPE_MIN_VALUE (itype) = size_zero_node;
5117   TYPE_MAX_VALUE (itype) = fold_convert (sizetype, maxval);
5118   TYPE_MODE (itype) = TYPE_MODE (sizetype);
5119   TYPE_SIZE (itype) = TYPE_SIZE (sizetype);
5120   TYPE_SIZE_UNIT (itype) = TYPE_SIZE_UNIT (sizetype);
5121   TYPE_ALIGN (itype) = TYPE_ALIGN (sizetype);
5122   TYPE_USER_ALIGN (itype) = TYPE_USER_ALIGN (sizetype);
5123
5124   if (host_integerp (maxval, 1))
5125     return type_hash_canon (tree_low_cst (maxval, 1), itype);
5126   else
5127     return itype;
5128 }
5129
5130 /* Builds a signed or unsigned integer type of precision PRECISION.
5131    Used for C bitfields whose precision does not match that of
5132    built-in target types.  */
5133 tree
5134 build_nonstandard_integer_type (unsigned HOST_WIDE_INT precision,
5135                                 int unsignedp)
5136 {
5137   tree itype = make_node (INTEGER_TYPE);
5138
5139   TYPE_PRECISION (itype) = precision;
5140
5141   if (unsignedp)
5142     fixup_unsigned_type (itype);
5143   else
5144     fixup_signed_type (itype);
5145
5146   if (host_integerp (TYPE_MAX_VALUE (itype), 1))
5147     return type_hash_canon (tree_low_cst (TYPE_MAX_VALUE (itype), 1), itype);
5148
5149   return itype;
5150 }
5151
5152 /* Create a range of some discrete type TYPE (an INTEGER_TYPE,
5153    ENUMERAL_TYPE or BOOLEAN_TYPE), with low bound LOWVAL and
5154    high bound HIGHVAL.  If TYPE is NULL, sizetype is used.  */
5155
5156 tree
5157 build_range_type (tree type, tree lowval, tree highval)
5158 {
5159   tree itype = make_node (INTEGER_TYPE);
5160
5161   TREE_TYPE (itype) = type;
5162   if (type == NULL_TREE)
5163     type = sizetype;
5164
5165   TYPE_MIN_VALUE (itype) = fold_convert (type, lowval);
5166   TYPE_MAX_VALUE (itype) = highval ? fold_convert (type, highval) : NULL;
5167
5168   TYPE_PRECISION (itype) = TYPE_PRECISION (type);
5169   TYPE_MODE (itype) = TYPE_MODE (type);
5170   TYPE_SIZE (itype) = TYPE_SIZE (type);
5171   TYPE_SIZE_UNIT (itype) = TYPE_SIZE_UNIT (type);
5172   TYPE_ALIGN (itype) = TYPE_ALIGN (type);
5173   TYPE_USER_ALIGN (itype) = TYPE_USER_ALIGN (type);
5174
5175   if (host_integerp (lowval, 0) && highval != 0 && host_integerp (highval, 0))
5176     return type_hash_canon (tree_low_cst (highval, 0)
5177                             - tree_low_cst (lowval, 0),
5178                             itype);
5179   else
5180     return itype;
5181 }
5182
5183 /* Just like build_index_type, but takes lowval and highval instead
5184    of just highval (maxval).  */
5185
5186 tree
5187 build_index_2_type (tree lowval, tree highval)
5188 {
5189   return build_range_type (sizetype, lowval, highval);
5190 }
5191
5192 /* Construct, lay out and return the type of arrays of elements with ELT_TYPE
5193    and number of elements specified by the range of values of INDEX_TYPE.
5194    If such a type has already been constructed, reuse it.  */
5195
5196 tree
5197 build_array_type (tree elt_type, tree index_type)
5198 {
5199   tree t;
5200   hashval_t hashcode = 0;
5201
5202   if (TREE_CODE (elt_type) == FUNCTION_TYPE)
5203     {
5204       error ("arrays of functions are not meaningful");
5205       elt_type = integer_type_node;
5206     }
5207
5208   t = make_node (ARRAY_TYPE);
5209   TREE_TYPE (t) = elt_type;
5210   TYPE_DOMAIN (t) = index_type;
5211
5212   if (index_type == 0)
5213     {
5214       tree save = t;
5215       hashcode = iterative_hash_object (TYPE_HASH (elt_type), hashcode);
5216       t = type_hash_canon (hashcode, t);
5217       if (save == t)
5218         layout_type (t);
5219       return t;
5220     }
5221
5222   hashcode = iterative_hash_object (TYPE_HASH (elt_type), hashcode);
5223   hashcode = iterative_hash_object (TYPE_HASH (index_type), hashcode);
5224   t = type_hash_canon (hashcode, t);
5225
5226   if (!COMPLETE_TYPE_P (t))
5227     layout_type (t);
5228   return t;
5229 }
5230
5231 /* Return the TYPE of the elements comprising
5232    the innermost dimension of ARRAY.  */
5233
5234 tree
5235 get_inner_array_type (tree array)
5236 {
5237   tree type = TREE_TYPE (array);
5238
5239   while (TREE_CODE (type) == ARRAY_TYPE)
5240     type = TREE_TYPE (type);
5241
5242   return type;
5243 }
5244
5245 /* Construct, lay out and return
5246    the type of functions returning type VALUE_TYPE
5247    given arguments of types ARG_TYPES.
5248    ARG_TYPES is a chain of TREE_LIST nodes whose TREE_VALUEs
5249    are data type nodes for the arguments of the function.
5250    If such a type has already been constructed, reuse it.  */
5251
5252 tree
5253 build_function_type (tree value_type, tree arg_types)
5254 {
5255   tree t;
5256   hashval_t hashcode = 0;
5257
5258   if (TREE_CODE (value_type) == FUNCTION_TYPE)
5259     {
5260       error ("function return type cannot be function");
5261       value_type = integer_type_node;
5262     }
5263
5264   /* Make a node of the sort we want.  */
5265   t = make_node (FUNCTION_TYPE);
5266   TREE_TYPE (t) = value_type;
5267   TYPE_ARG_TYPES (t) = arg_types;
5268
5269   /* If we already have such a type, use the old one.  */
5270   hashcode = iterative_hash_object (TYPE_HASH (value_type), hashcode);
5271   hashcode = type_hash_list (arg_types, hashcode);
5272   t = type_hash_canon (hashcode, t);
5273
5274   if (!COMPLETE_TYPE_P (t))
5275     layout_type (t);
5276   return t;
5277 }
5278
5279 /* Build a function type.  The RETURN_TYPE is the type returned by the
5280    function.  If additional arguments are provided, they are
5281    additional argument types.  The list of argument types must always
5282    be terminated by NULL_TREE.  */
5283
5284 tree
5285 build_function_type_list (tree return_type, ...)
5286 {
5287   tree t, args, last;
5288   va_list p;
5289
5290   va_start (p, return_type);
5291
5292   t = va_arg (p, tree);
5293   for (args = NULL_TREE; t != NULL_TREE; t = va_arg (p, tree))
5294     args = tree_cons (NULL_TREE, t, args);
5295
5296   if (args == NULL_TREE)
5297     args = void_list_node;
5298   else
5299     {
5300       last = args;
5301       args = nreverse (args);
5302       TREE_CHAIN (last) = void_list_node;
5303     }
5304   args = build_function_type (return_type, args);
5305
5306   va_end (p);
5307   return args;
5308 }
5309
5310 /* Build a METHOD_TYPE for a member of BASETYPE.  The RETTYPE (a TYPE)
5311    and ARGTYPES (a TREE_LIST) are the return type and arguments types
5312    for the method.  An implicit additional parameter (of type
5313    pointer-to-BASETYPE) is added to the ARGTYPES.  */
5314
5315 tree
5316 build_method_type_directly (tree basetype,
5317                             tree rettype,
5318                             tree argtypes)
5319 {
5320   tree t;
5321   tree ptype;
5322   int hashcode = 0;
5323
5324   /* Make a node of the sort we want.  */
5325   t = make_node (METHOD_TYPE);
5326
5327   TYPE_METHOD_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
5328   TREE_TYPE (t) = rettype;
5329   ptype = build_pointer_type (basetype);
5330
5331   /* The actual arglist for this function includes a "hidden" argument
5332      which is "this".  Put it into the list of argument types.  */
5333   argtypes = tree_cons (NULL_TREE, ptype, argtypes);
5334   TYPE_ARG_TYPES (t) = argtypes;
5335
5336   /* If we already have such a type, use the old one.  */
5337   hashcode = iterative_hash_object (TYPE_HASH (basetype), hashcode);
5338   hashcode = iterative_hash_object (TYPE_HASH (rettype), hashcode);
5339   hashcode = type_hash_list (argtypes, hashcode);
5340   t = type_hash_canon (hashcode, t);
5341
5342   if (!COMPLETE_TYPE_P (t))
5343     layout_type (t);
5344
5345   return t;
5346 }
5347
5348 /* Construct, lay out and return the type of methods belonging to class
5349    BASETYPE and whose arguments and values are described by TYPE.
5350    If that type exists already, reuse it.
5351    TYPE must be a FUNCTION_TYPE node.  */
5352
5353 tree
5354 build_method_type (tree basetype, tree type)
5355 {
5356   gcc_assert (TREE_CODE (type) == FUNCTION_TYPE);
5357
5358   return build_method_type_directly (basetype,
5359                                      TREE_TYPE (type),
5360                                      TYPE_ARG_TYPES (type));
5361 }
5362
5363 /* Construct, lay out and return the type of offsets to a value
5364    of type TYPE, within an object of type BASETYPE.
5365    If a suitable offset type exists already, reuse it.  */
5366
5367 tree
5368 build_offset_type (tree basetype, tree type)
5369 {
5370   tree t;
5371   hashval_t hashcode = 0;
5372
5373   /* Make a node of the sort we want.  */
5374   t = make_node (OFFSET_TYPE);
5375
5376   TYPE_OFFSET_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
5377   TREE_TYPE (t) = type;
5378
5379   /* If we already have such a type, use the old one.  */
5380   hashcode = iterative_hash_object (TYPE_HASH (basetype), hashcode);
5381   hashcode = iterative_hash_object (TYPE_HASH (type), hashcode);
5382   t = type_hash_canon (hashcode, t);
5383
5384   if (!COMPLETE_TYPE_P (t))
5385     layout_type (t);
5386
5387   return t;
5388 }
5389
5390 /* Create a complex type whose components are COMPONENT_TYPE.  */
5391
5392 tree
5393 build_complex_type (tree component_type)
5394 {
5395   tree t;
5396   hashval_t hashcode;
5397
5398   /* Make a node of the sort we want.  */
5399   t = make_node (COMPLEX_TYPE);
5400
5401   TREE_TYPE (t) = TYPE_MAIN_VARIANT (component_type);
5402
5403   /* If we already have such a type, use the old one.  */
5404   hashcode = iterative_hash_object (TYPE_HASH (component_type), 0);
5405   t = type_hash_canon (hashcode, t);
5406
5407   if (!COMPLETE_TYPE_P (t))
5408     layout_type (t);
5409
5410   /* If we are writing Dwarf2 output we need to create a name,
5411      since complex is a fundamental type.  */
5412   if ((write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
5413       && ! TYPE_NAME (t))
5414     {
5415       const char *name;
5416       if (component_type == char_type_node)
5417         name = "complex char";
5418       else if (component_type == signed_char_type_node)
5419         name = "complex signed char";
5420       else if (component_type == unsigned_char_type_node)
5421         name = "complex unsigned char";
5422       else if (component_type == short_integer_type_node)
5423         name = "complex short int";
5424       else if (component_type == short_unsigned_type_node)
5425         name = "complex short unsigned int";
5426       else if (component_type == integer_type_node)
5427         name = "complex int";
5428       else if (component_type == unsigned_type_node)
5429         name = "complex unsigned int";
5430       else if (component_type == long_integer_type_node)
5431         name = "complex long int";
5432       else if (component_type == long_unsigned_type_node)
5433         name = "complex long unsigned int";
5434       else if (component_type == long_long_integer_type_node)
5435         name = "complex long long int";
5436       else if (component_type == long_long_unsigned_type_node)
5437         name = "complex long long unsigned int";
5438       else
5439         name = 0;
5440
5441       if (name != 0)
5442         TYPE_NAME (t) = get_identifier (name);
5443     }
5444
5445   return build_qualified_type (t, TYPE_QUALS (component_type));
5446 }
5447 \f
5448 /* Return OP, stripped of any conversions to wider types as much as is safe.
5449    Converting the value back to OP's type makes a value equivalent to OP.
5450
5451    If FOR_TYPE is nonzero, we return a value which, if converted to
5452    type FOR_TYPE, would be equivalent to converting OP to type FOR_TYPE.
5453
5454    If FOR_TYPE is nonzero, unaligned bit-field references may be changed to the
5455    narrowest type that can hold the value, even if they don't exactly fit.
5456    Otherwise, bit-field references are changed to a narrower type
5457    only if they can be fetched directly from memory in that type.
5458
5459    OP must have integer, real or enumeral type.  Pointers are not allowed!
5460
5461    There are some cases where the obvious value we could return
5462    would regenerate to OP if converted to OP's type,
5463    but would not extend like OP to wider types.
5464    If FOR_TYPE indicates such extension is contemplated, we eschew such values.
5465    For example, if OP is (unsigned short)(signed char)-1,
5466    we avoid returning (signed char)-1 if FOR_TYPE is int,
5467    even though extending that to an unsigned short would regenerate OP,
5468    since the result of extending (signed char)-1 to (int)
5469    is different from (int) OP.  */
5470
5471 tree
5472 get_unwidened (tree op, tree for_type)
5473 {
5474   /* Set UNS initially if converting OP to FOR_TYPE is a zero-extension.  */
5475   tree type = TREE_TYPE (op);
5476   unsigned final_prec
5477     = TYPE_PRECISION (for_type != 0 ? for_type : type);
5478   int uns
5479     = (for_type != 0 && for_type != type
5480        && final_prec > TYPE_PRECISION (type)
5481        && TYPE_UNSIGNED (type));
5482   tree win = op;
5483
5484   while (TREE_CODE (op) == NOP_EXPR
5485          || TREE_CODE (op) == CONVERT_EXPR)
5486     {
5487       int bitschange;
5488
5489       /* TYPE_PRECISION on vector types has different meaning
5490          (TYPE_VECTOR_SUBPARTS) and casts from vectors are view conversions,
5491          so avoid them here.  */
5492       if (TREE_CODE (TREE_TYPE (TREE_OPERAND (op, 0))) == VECTOR_TYPE)
5493         break;
5494
5495       bitschange = TYPE_PRECISION (TREE_TYPE (op))
5496                    - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0)));
5497
5498       /* Truncations are many-one so cannot be removed.
5499          Unless we are later going to truncate down even farther.  */
5500       if (bitschange < 0
5501           && final_prec > TYPE_PRECISION (TREE_TYPE (op)))
5502         break;
5503
5504       /* See what's inside this conversion.  If we decide to strip it,
5505          we will set WIN.  */
5506       op = TREE_OPERAND (op, 0);
5507
5508       /* If we have not stripped any zero-extensions (uns is 0),
5509          we can strip any kind of extension.
5510          If we have previously stripped a zero-extension,
5511          only zero-extensions can safely be stripped.
5512          Any extension can be stripped if the bits it would produce
5513          are all going to be discarded later by truncating to FOR_TYPE.  */
5514
5515       if (bitschange > 0)
5516         {
5517           if (! uns || final_prec <= TYPE_PRECISION (TREE_TYPE (op)))
5518             win = op;
5519           /* TYPE_UNSIGNED says whether this is a zero-extension.
5520              Let's avoid computing it if it does not affect WIN
5521              and if UNS will not be needed again.  */
5522           if ((uns
5523                || TREE_CODE (op) == NOP_EXPR
5524                || TREE_CODE (op) == CONVERT_EXPR)
5525               && TYPE_UNSIGNED (TREE_TYPE (op)))
5526             {
5527               uns = 1;
5528               win = op;
5529             }
5530         }
5531     }
5532
5533   if (TREE_CODE (op) == COMPONENT_REF
5534       /* Since type_for_size always gives an integer type.  */
5535       && TREE_CODE (type) != REAL_TYPE
5536       /* Don't crash if field not laid out yet.  */
5537       && DECL_SIZE (TREE_OPERAND (op, 1)) != 0
5538       && host_integerp (DECL_SIZE (TREE_OPERAND (op, 1)), 1))
5539     {
5540       unsigned int innerprec
5541         = tree_low_cst (DECL_SIZE (TREE_OPERAND (op, 1)), 1);
5542       int unsignedp = (DECL_UNSIGNED (TREE_OPERAND (op, 1))
5543                        || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op, 1))));
5544       type = lang_hooks.types.type_for_size (innerprec, unsignedp);
5545
5546       /* We can get this structure field in the narrowest type it fits in.
5547          If FOR_TYPE is 0, do this only for a field that matches the
5548          narrower type exactly and is aligned for it
5549          The resulting extension to its nominal type (a fullword type)
5550          must fit the same conditions as for other extensions.  */
5551
5552       if (type != 0
5553           && INT_CST_LT_UNSIGNED (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (op)))
5554           && (for_type || ! DECL_BIT_FIELD (TREE_OPERAND (op, 1)))
5555           && (! uns || final_prec <= innerprec || unsignedp))
5556         {
5557           win = build3 (COMPONENT_REF, type, TREE_OPERAND (op, 0),
5558                         TREE_OPERAND (op, 1), NULL_TREE);
5559           TREE_SIDE_EFFECTS (win) = TREE_SIDE_EFFECTS (op);
5560           TREE_THIS_VOLATILE (win) = TREE_THIS_VOLATILE (op);
5561         }
5562     }
5563
5564   return win;
5565 }
5566 \f
5567 /* Return OP or a simpler expression for a narrower value
5568    which can be sign-extended or zero-extended to give back OP.
5569    Store in *UNSIGNEDP_PTR either 1 if the value should be zero-extended
5570    or 0 if the value should be sign-extended.  */
5571
5572 tree
5573 get_narrower (tree op, int *unsignedp_ptr)
5574 {
5575   int uns = 0;
5576   int first = 1;
5577   tree win = op;
5578   bool integral_p = INTEGRAL_TYPE_P (TREE_TYPE (op));
5579
5580   while (TREE_CODE (op) == NOP_EXPR)
5581     {
5582       int bitschange
5583         = (TYPE_PRECISION (TREE_TYPE (op))
5584            - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0))));
5585
5586       /* Truncations are many-one so cannot be removed.  */
5587       if (bitschange < 0)
5588         break;
5589
5590       /* See what's inside this conversion.  If we decide to strip it,
5591          we will set WIN.  */
5592
5593       if (bitschange > 0)
5594         {
5595           op = TREE_OPERAND (op, 0);
5596           /* An extension: the outermost one can be stripped,
5597              but remember whether it is zero or sign extension.  */
5598           if (first)
5599             uns = TYPE_UNSIGNED (TREE_TYPE (op));
5600           /* Otherwise, if a sign extension has been stripped,
5601              only sign extensions can now be stripped;
5602              if a zero extension has been stripped, only zero-extensions.  */
5603           else if (uns != TYPE_UNSIGNED (TREE_TYPE (op)))
5604             break;
5605           first = 0;
5606         }
5607       else /* bitschange == 0 */
5608         {
5609           /* A change in nominal type can always be stripped, but we must
5610              preserve the unsignedness.  */
5611           if (first)
5612             uns = TYPE_UNSIGNED (TREE_TYPE (op));
5613           first = 0;
5614           op = TREE_OPERAND (op, 0);
5615           /* Keep trying to narrow, but don't assign op to win if it
5616              would turn an integral type into something else.  */
5617           if (INTEGRAL_TYPE_P (TREE_TYPE (op)) != integral_p)
5618             continue;
5619         }
5620
5621       win = op;
5622     }
5623
5624   if (TREE_CODE (op) == COMPONENT_REF
5625       /* Since type_for_size always gives an integer type.  */
5626       && TREE_CODE (TREE_TYPE (op)) != REAL_TYPE
5627       /* Ensure field is laid out already.  */
5628       && DECL_SIZE (TREE_OPERAND (op, 1)) != 0
5629       && host_integerp (DECL_SIZE (TREE_OPERAND (op, 1)), 1))
5630     {
5631       unsigned HOST_WIDE_INT innerprec
5632         = tree_low_cst (DECL_SIZE (TREE_OPERAND (op, 1)), 1);
5633       int unsignedp = (DECL_UNSIGNED (TREE_OPERAND (op, 1))
5634                        || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op, 1))));
5635       tree type = lang_hooks.types.type_for_size (innerprec, unsignedp);
5636
5637       /* We can get this structure field in a narrower type that fits it,
5638          but the resulting extension to its nominal type (a fullword type)
5639          must satisfy the same conditions as for other extensions.
5640
5641          Do this only for fields that are aligned (not bit-fields),
5642          because when bit-field insns will be used there is no
5643          advantage in doing this.  */
5644
5645       if (innerprec < TYPE_PRECISION (TREE_TYPE (op))
5646           && ! DECL_BIT_FIELD (TREE_OPERAND (op, 1))
5647           && (first || uns == DECL_UNSIGNED (TREE_OPERAND (op, 1)))
5648           && type != 0)
5649         {
5650           if (first)
5651             uns = DECL_UNSIGNED (TREE_OPERAND (op, 1));
5652           win = build3 (COMPONENT_REF, type, TREE_OPERAND (op, 0),
5653                         TREE_OPERAND (op, 1), NULL_TREE);
5654           TREE_SIDE_EFFECTS (win) = TREE_SIDE_EFFECTS (op);
5655           TREE_THIS_VOLATILE (win) = TREE_THIS_VOLATILE (op);
5656         }
5657     }
5658   *unsignedp_ptr = uns;
5659   return win;
5660 }
5661 \f
5662 /* Nonzero if integer constant C has a value that is permissible
5663    for type TYPE (an INTEGER_TYPE).  */
5664
5665 int
5666 int_fits_type_p (tree c, tree type)
5667 {
5668   tree type_low_bound = TYPE_MIN_VALUE (type);
5669   tree type_high_bound = TYPE_MAX_VALUE (type);
5670   bool ok_for_low_bound, ok_for_high_bound;
5671   tree tmp;
5672
5673   /* If at least one bound of the type is a constant integer, we can check
5674      ourselves and maybe make a decision. If no such decision is possible, but
5675      this type is a subtype, try checking against that.  Otherwise, use
5676      force_fit_type, which checks against the precision.
5677
5678      Compute the status for each possibly constant bound, and return if we see
5679      one does not match. Use ok_for_xxx_bound for this purpose, assigning -1
5680      for "unknown if constant fits", 0 for "constant known *not* to fit" and 1
5681      for "constant known to fit".  */
5682
5683   /* Check if C >= type_low_bound.  */
5684   if (type_low_bound && TREE_CODE (type_low_bound) == INTEGER_CST)
5685     {
5686       if (tree_int_cst_lt (c, type_low_bound))
5687         return 0;
5688       ok_for_low_bound = true;
5689     }
5690   else
5691     ok_for_low_bound = false;
5692
5693   /* Check if c <= type_high_bound.  */
5694   if (type_high_bound && TREE_CODE (type_high_bound) == INTEGER_CST)
5695     {
5696       if (tree_int_cst_lt (type_high_bound, c))
5697         return 0;
5698       ok_for_high_bound = true;
5699     }
5700   else
5701     ok_for_high_bound = false;
5702
5703   /* If the constant fits both bounds, the result is known.  */
5704   if (ok_for_low_bound && ok_for_high_bound)
5705     return 1;
5706
5707   /* Perform some generic filtering which may allow making a decision
5708      even if the bounds are not constant.  First, negative integers
5709      never fit in unsigned types, */
5710   if (TYPE_UNSIGNED (type) && tree_int_cst_sgn (c) < 0)
5711     return 0;
5712
5713   /* Second, narrower types always fit in wider ones.  */
5714   if (TYPE_PRECISION (type) > TYPE_PRECISION (TREE_TYPE (c)))
5715     return 1;
5716
5717   /* Third, unsigned integers with top bit set never fit signed types.  */
5718   if (! TYPE_UNSIGNED (type)
5719       && TYPE_UNSIGNED (TREE_TYPE (c))
5720       && tree_int_cst_msb (c))
5721     return 0;
5722
5723   /* If we haven't been able to decide at this point, there nothing more we
5724      can check ourselves here.  Look at the base type if we have one and it
5725      has the same precision.  */
5726   if (TREE_CODE (type) == INTEGER_TYPE
5727       && TREE_TYPE (type) != 0
5728       && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (type)))
5729     return int_fits_type_p (c, TREE_TYPE (type));
5730
5731   /* Or to force_fit_type, if nothing else.  */
5732   tmp = copy_node (c);
5733   TREE_TYPE (tmp) = type;
5734   tmp = force_fit_type (tmp, -1, false, false);
5735   return TREE_INT_CST_HIGH (tmp) == TREE_INT_CST_HIGH (c)
5736          && TREE_INT_CST_LOW (tmp) == TREE_INT_CST_LOW (c);
5737 }
5738
5739 /* Subprogram of following function.  Called by walk_tree.
5740
5741    Return *TP if it is an automatic variable or parameter of the
5742    function passed in as DATA.  */
5743
5744 static tree
5745 find_var_from_fn (tree *tp, int *walk_subtrees, void *data)
5746 {
5747   tree fn = (tree) data;
5748
5749   if (TYPE_P (*tp))
5750     *walk_subtrees = 0;
5751
5752   else if (DECL_P (*tp)
5753            && lang_hooks.tree_inlining.auto_var_in_fn_p (*tp, fn))
5754     return *tp;
5755
5756   return NULL_TREE;
5757 }
5758
5759 /* Returns true if T is, contains, or refers to a type with variable
5760    size.  For METHOD_TYPEs and FUNCTION_TYPEs we exclude the
5761    arguments, but not the return type.  If FN is nonzero, only return
5762    true if a modifier of the type or position of FN is a variable or
5763    parameter inside FN.
5764
5765    This concept is more general than that of C99 'variably modified types':
5766    in C99, a struct type is never variably modified because a VLA may not
5767    appear as a structure member.  However, in GNU C code like:
5768
5769      struct S { int i[f()]; };
5770
5771    is valid, and other languages may define similar constructs.  */
5772
5773 bool
5774 variably_modified_type_p (tree type, tree fn)
5775 {
5776   tree t;
5777
5778 /* Test if T is either variable (if FN is zero) or an expression containing
5779    a variable in FN.  */
5780 #define RETURN_TRUE_IF_VAR(T)                                           \
5781   do { tree _t = (T);                                                   \
5782     if (_t && _t != error_mark_node && TREE_CODE (_t) != INTEGER_CST    \
5783         && (!fn || walk_tree (&_t, find_var_from_fn, fn, NULL)))        \
5784       return true;  } while (0)
5785
5786   if (type == error_mark_node)
5787     return false;
5788
5789   /* If TYPE itself has variable size, it is variably modified.  */
5790   RETURN_TRUE_IF_VAR (TYPE_SIZE (type));
5791   RETURN_TRUE_IF_VAR (TYPE_SIZE_UNIT (type));
5792
5793   switch (TREE_CODE (type))
5794     {
5795     case POINTER_TYPE:
5796     case REFERENCE_TYPE:
5797     case VECTOR_TYPE:
5798       if (variably_modified_type_p (TREE_TYPE (type), fn))
5799         return true;
5800       break;
5801
5802     case FUNCTION_TYPE:
5803     case METHOD_TYPE:
5804       /* If TYPE is a function type, it is variably modified if the
5805          return type is variably modified.  */
5806       if (variably_modified_type_p (TREE_TYPE (type), fn))
5807           return true;
5808       break;
5809
5810     case INTEGER_TYPE:
5811     case REAL_TYPE:
5812     case ENUMERAL_TYPE:
5813     case BOOLEAN_TYPE:
5814       /* Scalar types are variably modified if their end points
5815          aren't constant.  */
5816       RETURN_TRUE_IF_VAR (TYPE_MIN_VALUE (type));
5817       RETURN_TRUE_IF_VAR (TYPE_MAX_VALUE (type));
5818       break;
5819
5820     case RECORD_TYPE:
5821     case UNION_TYPE:
5822     case QUAL_UNION_TYPE:
5823       /* We can't see if any of the fields are variably-modified by the
5824          definition we normally use, since that would produce infinite
5825          recursion via pointers.  */
5826       /* This is variably modified if some field's type is.  */
5827       for (t = TYPE_FIELDS (type); t; t = TREE_CHAIN (t))
5828         if (TREE_CODE (t) == FIELD_DECL)
5829           {
5830             RETURN_TRUE_IF_VAR (DECL_FIELD_OFFSET (t));
5831             RETURN_TRUE_IF_VAR (DECL_SIZE (t));
5832             RETURN_TRUE_IF_VAR (DECL_SIZE_UNIT (t));
5833
5834             if (TREE_CODE (type) == QUAL_UNION_TYPE)
5835               RETURN_TRUE_IF_VAR (DECL_QUALIFIER (t));
5836           }
5837         break;
5838
5839     case ARRAY_TYPE:
5840       /* Do not call ourselves to avoid infinite recursion.  This is
5841          variably modified if the element type is.  */
5842       RETURN_TRUE_IF_VAR (TYPE_SIZE (TREE_TYPE (type)));
5843       RETURN_TRUE_IF_VAR (TYPE_SIZE_UNIT (TREE_TYPE (type)));
5844       break;
5845
5846     default:
5847       break;
5848     }
5849
5850   /* The current language may have other cases to check, but in general,
5851      all other types are not variably modified.  */
5852   return lang_hooks.tree_inlining.var_mod_type_p (type, fn);
5853
5854 #undef RETURN_TRUE_IF_VAR
5855 }
5856
5857 /* Given a DECL or TYPE, return the scope in which it was declared, or
5858    NULL_TREE if there is no containing scope.  */
5859
5860 tree
5861 get_containing_scope (tree t)
5862 {
5863   return (TYPE_P (t) ? TYPE_CONTEXT (t) : DECL_CONTEXT (t));
5864 }
5865
5866 /* Return the innermost context enclosing DECL that is
5867    a FUNCTION_DECL, or zero if none.  */
5868
5869 tree
5870 decl_function_context (tree decl)
5871 {
5872   tree context;
5873
5874   if (TREE_CODE (decl) == ERROR_MARK)
5875     return 0;
5876
5877   /* C++ virtual functions use DECL_CONTEXT for the class of the vtable
5878      where we look up the function at runtime.  Such functions always take
5879      a first argument of type 'pointer to real context'.
5880
5881      C++ should really be fixed to use DECL_CONTEXT for the real context,
5882      and use something else for the "virtual context".  */
5883   else if (TREE_CODE (decl) == FUNCTION_DECL && DECL_VINDEX (decl))
5884     context
5885       = TYPE_MAIN_VARIANT
5886         (TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (decl)))));
5887   else
5888     context = DECL_CONTEXT (decl);
5889
5890   while (context && TREE_CODE (context) != FUNCTION_DECL)
5891     {
5892       if (TREE_CODE (context) == BLOCK)
5893         context = BLOCK_SUPERCONTEXT (context);
5894       else
5895         context = get_containing_scope (context);
5896     }
5897
5898   return context;
5899 }
5900
5901 /* Return the innermost context enclosing DECL that is
5902    a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE, or zero if none.
5903    TYPE_DECLs and FUNCTION_DECLs are transparent to this function.  */
5904
5905 tree
5906 decl_type_context (tree decl)
5907 {
5908   tree context = DECL_CONTEXT (decl);
5909
5910   while (context)
5911     switch (TREE_CODE (context))
5912       {
5913       case NAMESPACE_DECL:
5914       case TRANSLATION_UNIT_DECL:
5915         return NULL_TREE;
5916
5917       case RECORD_TYPE:
5918       case UNION_TYPE:
5919       case QUAL_UNION_TYPE:
5920         return context;
5921
5922       case TYPE_DECL:
5923       case FUNCTION_DECL:
5924         context = DECL_CONTEXT (context);
5925         break;
5926
5927       case BLOCK:
5928         context = BLOCK_SUPERCONTEXT (context);
5929         break;
5930
5931       default:
5932         gcc_unreachable ();
5933       }
5934
5935   return NULL_TREE;
5936 }
5937
5938 /* CALL is a CALL_EXPR.  Return the declaration for the function
5939    called, or NULL_TREE if the called function cannot be
5940    determined.  */
5941
5942 tree
5943 get_callee_fndecl (tree call)
5944 {
5945   tree addr;
5946
5947   if (call == error_mark_node)
5948     return call;
5949
5950   /* It's invalid to call this function with anything but a
5951      CALL_EXPR.  */
5952   gcc_assert (TREE_CODE (call) == CALL_EXPR);
5953
5954   /* The first operand to the CALL is the address of the function
5955      called.  */
5956   addr = TREE_OPERAND (call, 0);
5957
5958   STRIP_NOPS (addr);
5959
5960   /* If this is a readonly function pointer, extract its initial value.  */
5961   if (DECL_P (addr) && TREE_CODE (addr) != FUNCTION_DECL
5962       && TREE_READONLY (addr) && ! TREE_THIS_VOLATILE (addr)
5963       && DECL_INITIAL (addr))
5964     addr = DECL_INITIAL (addr);
5965
5966   /* If the address is just `&f' for some function `f', then we know
5967      that `f' is being called.  */
5968   if (TREE_CODE (addr) == ADDR_EXPR
5969       && TREE_CODE (TREE_OPERAND (addr, 0)) == FUNCTION_DECL)
5970     return TREE_OPERAND (addr, 0);
5971
5972   /* We couldn't figure out what was being called.  Maybe the front
5973      end has some idea.  */
5974   return lang_hooks.lang_get_callee_fndecl (call);
5975 }
5976
5977 /* Print debugging information about tree nodes generated during the compile,
5978    and any language-specific information.  */
5979
5980 void
5981 dump_tree_statistics (void)
5982 {
5983 #ifdef GATHER_STATISTICS
5984   int i;
5985   int total_nodes, total_bytes;
5986 #endif
5987
5988   fprintf (stderr, "\n??? tree nodes created\n\n");
5989 #ifdef GATHER_STATISTICS
5990   fprintf (stderr, "Kind                   Nodes      Bytes\n");
5991   fprintf (stderr, "---------------------------------------\n");
5992   total_nodes = total_bytes = 0;
5993   for (i = 0; i < (int) all_kinds; i++)
5994     {
5995       fprintf (stderr, "%-20s %7d %10d\n", tree_node_kind_names[i],
5996                tree_node_counts[i], tree_node_sizes[i]);
5997       total_nodes += tree_node_counts[i];
5998       total_bytes += tree_node_sizes[i];
5999     }
6000   fprintf (stderr, "---------------------------------------\n");
6001   fprintf (stderr, "%-20s %7d %10d\n", "Total", total_nodes, total_bytes);
6002   fprintf (stderr, "---------------------------------------\n");
6003   ssanames_print_statistics ();
6004   phinodes_print_statistics ();
6005 #else
6006   fprintf (stderr, "(No per-node statistics)\n");
6007 #endif
6008   print_type_hash_statistics ();
6009   print_debug_expr_statistics ();
6010   print_value_expr_statistics ();
6011   print_restrict_base_statistics ();
6012   lang_hooks.print_statistics ();
6013 }
6014 \f
6015 #define FILE_FUNCTION_FORMAT "_GLOBAL__%s_%s"
6016
6017 /* Generate a crc32 of a string.  */
6018
6019 unsigned
6020 crc32_string (unsigned chksum, const char *string)
6021 {
6022   do
6023     {
6024       unsigned value = *string << 24;
6025       unsigned ix;
6026
6027       for (ix = 8; ix--; value <<= 1)
6028         {
6029           unsigned feedback;
6030
6031           feedback = (value ^ chksum) & 0x80000000 ? 0x04c11db7 : 0;
6032           chksum <<= 1;
6033           chksum ^= feedback;
6034         }
6035     }
6036   while (*string++);
6037   return chksum;
6038 }
6039
6040 /* P is a string that will be used in a symbol.  Mask out any characters
6041    that are not valid in that context.  */
6042
6043 void
6044 clean_symbol_name (char *p)
6045 {
6046   for (; *p; p++)
6047     if (! (ISALNUM (*p)
6048 #ifndef NO_DOLLAR_IN_LABEL      /* this for `$'; unlikely, but... -- kr */
6049             || *p == '$'
6050 #endif
6051 #ifndef NO_DOT_IN_LABEL         /* this for `.'; unlikely, but...  */
6052             || *p == '.'
6053 #endif
6054            ))
6055       *p = '_';
6056 }
6057
6058 /* Generate a name for a function unique to this translation unit.
6059    TYPE is some string to identify the purpose of this function to the
6060    linker or collect2.  */
6061
6062 tree
6063 get_file_function_name_long (const char *type)
6064 {
6065   char *buf;
6066   const char *p;
6067   char *q;
6068
6069   if (first_global_object_name)
6070     {
6071       p = first_global_object_name;
6072
6073       /* For type 'F', the generated name must be unique not only to this
6074          translation unit but also to any given link.  Since global names
6075          can be overloaded, we concatenate the first global object name
6076          with a string derived from the file name of this object.  */
6077       if (!strcmp (type, "F"))
6078         {
6079           const char *file = main_input_filename;
6080
6081           if (! file)
6082             file = input_filename;
6083
6084           q = alloca (strlen (p) + 10);
6085           sprintf (q, "%s_%08X", p, crc32_string (0, file));
6086
6087           p = q;
6088         }
6089     }
6090   else
6091     {
6092       /* We don't have anything that we know to be unique to this translation
6093          unit, so use what we do have and throw in some randomness.  */
6094       unsigned len;
6095       const char *name = weak_global_object_name;
6096       const char *file = main_input_filename;
6097
6098       if (! name)
6099         name = "";
6100       if (! file)
6101         file = input_filename;
6102
6103       len = strlen (file);
6104       q = alloca (9 * 2 + len + 1);
6105       memcpy (q, file, len + 1);
6106       clean_symbol_name (q);
6107
6108       sprintf (q + len, "_%08X_%08X", crc32_string (0, name),
6109                crc32_string (0, flag_random_seed));
6110
6111       p = q;
6112     }
6113
6114   buf = alloca (sizeof (FILE_FUNCTION_FORMAT) + strlen (p) + strlen (type));
6115
6116   /* Set up the name of the file-level functions we may need.
6117      Use a global object (which is already required to be unique over
6118      the program) rather than the file name (which imposes extra
6119      constraints).  */
6120   sprintf (buf, FILE_FUNCTION_FORMAT, type, p);
6121
6122   return get_identifier (buf);
6123 }
6124
6125 /* If KIND=='I', return a suitable global initializer (constructor) name.
6126    If KIND=='D', return a suitable global clean-up (destructor) name.  */
6127
6128 tree
6129 get_file_function_name (int kind)
6130 {
6131   char p[2];
6132
6133   p[0] = kind;
6134   p[1] = 0;
6135
6136   return get_file_function_name_long (p);
6137 }
6138 \f
6139 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
6140
6141 /* Complain that the tree code of NODE does not match the expected 0
6142    terminated list of trailing codes. The trailing code list can be
6143    empty, for a more vague error message.  FILE, LINE, and FUNCTION
6144    are of the caller.  */
6145
6146 void
6147 tree_check_failed (const tree node, const char *file,
6148                    int line, const char *function, ...)
6149 {
6150   va_list args;
6151   char *buffer;
6152   unsigned length = 0;
6153   int code;
6154
6155   va_start (args, function);
6156   while ((code = va_arg (args, int)))
6157     length += 4 + strlen (tree_code_name[code]);
6158   va_end (args);
6159   if (length)
6160     {
6161       va_start (args, function);
6162       length += strlen ("expected ");
6163       buffer = alloca (length);
6164       length = 0;
6165       while ((code = va_arg (args, int)))
6166         {
6167           const char *prefix = length ? " or " : "expected ";
6168
6169           strcpy (buffer + length, prefix);
6170           length += strlen (prefix);
6171           strcpy (buffer + length, tree_code_name[code]);
6172           length += strlen (tree_code_name[code]);
6173         }
6174       va_end (args);
6175     }
6176   else
6177     buffer = (char *)"unexpected node";
6178
6179   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6180                   buffer, tree_code_name[TREE_CODE (node)],
6181                   function, trim_filename (file), line);
6182 }
6183
6184 /* Complain that the tree code of NODE does match the expected 0
6185    terminated list of trailing codes. FILE, LINE, and FUNCTION are of
6186    the caller.  */
6187
6188 void
6189 tree_not_check_failed (const tree node, const char *file,
6190                        int line, const char *function, ...)
6191 {
6192   va_list args;
6193   char *buffer;
6194   unsigned length = 0;
6195   int code;
6196
6197   va_start (args, function);
6198   while ((code = va_arg (args, int)))
6199     length += 4 + strlen (tree_code_name[code]);
6200   va_end (args);
6201   va_start (args, function);
6202   buffer = alloca (length);
6203   length = 0;
6204   while ((code = va_arg (args, int)))
6205     {
6206       if (length)
6207         {
6208           strcpy (buffer + length, " or ");
6209           length += 4;
6210         }
6211       strcpy (buffer + length, tree_code_name[code]);
6212       length += strlen (tree_code_name[code]);
6213     }
6214   va_end (args);
6215
6216   internal_error ("tree check: expected none of %s, have %s in %s, at %s:%d",
6217                   buffer, tree_code_name[TREE_CODE (node)],
6218                   function, trim_filename (file), line);
6219 }
6220
6221 /* Similar to tree_check_failed, except that we check for a class of tree
6222    code, given in CL.  */
6223
6224 void
6225 tree_class_check_failed (const tree node, const enum tree_code_class cl,
6226                          const char *file, int line, const char *function)
6227 {
6228   internal_error
6229     ("tree check: expected class %qs, have %qs (%s) in %s, at %s:%d",
6230      TREE_CODE_CLASS_STRING (cl),
6231      TREE_CODE_CLASS_STRING (TREE_CODE_CLASS (TREE_CODE (node))),
6232      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6233 }
6234
6235 /* Similar to tree_check_failed, except that instead of specifying a
6236    dozen codes, use the knowledge that they're all sequential.  */
6237
6238 void
6239 tree_range_check_failed (const tree node, const char *file, int line,
6240                          const char *function, enum tree_code c1,
6241                          enum tree_code c2)
6242 {
6243   char *buffer;
6244   unsigned length = 0;
6245   enum tree_code c;
6246
6247   for (c = c1; c <= c2; ++c)
6248     length += 4 + strlen (tree_code_name[c]);
6249
6250   length += strlen ("expected ");
6251   buffer = alloca (length);
6252   length = 0;
6253
6254   for (c = c1; c <= c2; ++c)
6255     {
6256       const char *prefix = length ? " or " : "expected ";
6257
6258       strcpy (buffer + length, prefix);
6259       length += strlen (prefix);
6260       strcpy (buffer + length, tree_code_name[c]);
6261       length += strlen (tree_code_name[c]);
6262     }
6263
6264   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6265                   buffer, tree_code_name[TREE_CODE (node)],
6266                   function, trim_filename (file), line);
6267 }
6268
6269
6270 /* Similar to tree_check_failed, except that we check that a tree does
6271    not have the specified code, given in CL.  */
6272
6273 void
6274 tree_not_class_check_failed (const tree node, const enum tree_code_class cl,
6275                              const char *file, int line, const char *function)
6276 {
6277   internal_error
6278     ("tree check: did not expect class %qs, have %qs (%s) in %s, at %s:%d",
6279      TREE_CODE_CLASS_STRING (cl),
6280      TREE_CODE_CLASS_STRING (TREE_CODE_CLASS (TREE_CODE (node))),
6281      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6282 }
6283
6284
6285 /* Similar to tree_check_failed but applied to OMP_CLAUSE codes.  */
6286
6287 void
6288 omp_clause_check_failed (const tree node, const char *file, int line,
6289                          const char *function, enum omp_clause_code code)
6290 {
6291   internal_error ("tree check: expected omp_clause %s, have %s in %s, at %s:%d",
6292                   omp_clause_code_name[code], tree_code_name[TREE_CODE (node)],
6293                   function, trim_filename (file), line);
6294 }
6295
6296
6297 /* Similar to tree_range_check_failed but applied to OMP_CLAUSE codes.  */
6298
6299 void
6300 omp_clause_range_check_failed (const tree node, const char *file, int line,
6301                                const char *function, enum omp_clause_code c1,
6302                                enum omp_clause_code c2)
6303 {
6304   char *buffer;
6305   unsigned length = 0;
6306   enum omp_clause_code c;
6307
6308   for (c = c1; c <= c2; ++c)
6309     length += 4 + strlen (omp_clause_code_name[c]);
6310
6311   length += strlen ("expected ");
6312   buffer = alloca (length);
6313   length = 0;
6314
6315   for (c = c1; c <= c2; ++c)
6316     {
6317       const char *prefix = length ? " or " : "expected ";
6318
6319       strcpy (buffer + length, prefix);
6320       length += strlen (prefix);
6321       strcpy (buffer + length, omp_clause_code_name[c]);
6322       length += strlen (omp_clause_code_name[c]);
6323     }
6324
6325   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6326                   buffer, omp_clause_code_name[TREE_CODE (node)],
6327                   function, trim_filename (file), line);
6328 }
6329
6330
6331 #undef DEFTREESTRUCT
6332 #define DEFTREESTRUCT(VAL, NAME) NAME,
6333
6334 static const char *ts_enum_names[] = {
6335 #include "treestruct.def"
6336 };
6337 #undef DEFTREESTRUCT
6338
6339 #define TS_ENUM_NAME(EN) (ts_enum_names[(EN)])
6340
6341 /* Similar to tree_class_check_failed, except that we check for
6342    whether CODE contains the tree structure identified by EN.  */
6343
6344 void
6345 tree_contains_struct_check_failed (const tree node,
6346                                    const enum tree_node_structure_enum en,
6347                                    const char *file, int line,
6348                                    const char *function)
6349 {
6350   internal_error
6351     ("tree check: expected tree that contains %qs structure, have %qs  in %s, at %s:%d",
6352      TS_ENUM_NAME(en),
6353      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6354 }
6355
6356
6357 /* Similar to above, except that the check is for the bounds of a TREE_VEC's
6358    (dynamically sized) vector.  */
6359
6360 void
6361 tree_vec_elt_check_failed (int idx, int len, const char *file, int line,
6362                            const char *function)
6363 {
6364   internal_error
6365     ("tree check: accessed elt %d of tree_vec with %d elts in %s, at %s:%d",
6366      idx + 1, len, function, trim_filename (file), line);
6367 }
6368
6369 /* Similar to above, except that the check is for the bounds of a PHI_NODE's
6370    (dynamically sized) vector.  */
6371
6372 void
6373 phi_node_elt_check_failed (int idx, int len, const char *file, int line,
6374                             const char *function)
6375 {
6376   internal_error
6377     ("tree check: accessed elt %d of phi_node with %d elts in %s, at %s:%d",
6378      idx + 1, len, function, trim_filename (file), line);
6379 }
6380
6381 /* Similar to above, except that the check is for the bounds of the operand
6382    vector of an expression node.  */
6383
6384 void
6385 tree_operand_check_failed (int idx, enum tree_code code, const char *file,
6386                            int line, const char *function)
6387 {
6388   internal_error
6389     ("tree check: accessed operand %d of %s with %d operands in %s, at %s:%d",
6390      idx + 1, tree_code_name[code], TREE_CODE_LENGTH (code),
6391      function, trim_filename (file), line);
6392 }
6393
6394 /* Similar to above, except that the check is for the number of
6395    operands of an OMP_CLAUSE node.  */
6396
6397 void
6398 omp_clause_operand_check_failed (int idx, tree t, const char *file,
6399                                  int line, const char *function)
6400 {
6401   internal_error
6402     ("tree check: accessed operand %d of omp_clause %s with %d operands "
6403      "in %s, at %s:%d", idx + 1, omp_clause_code_name[OMP_CLAUSE_CODE (t)],
6404      omp_clause_num_ops [OMP_CLAUSE_CODE (t)], function,
6405      trim_filename (file), line);
6406 }
6407 #endif /* ENABLE_TREE_CHECKING */
6408 \f
6409 /* Create a new vector type node holding SUBPARTS units of type INNERTYPE,
6410    and mapped to the machine mode MODE.  Initialize its fields and build
6411    the information necessary for debugging output.  */
6412
6413 static tree
6414 make_vector_type (tree innertype, int nunits, enum machine_mode mode)
6415 {
6416   tree t = make_node (VECTOR_TYPE);
6417
6418   TREE_TYPE (t) = TYPE_MAIN_VARIANT (innertype);
6419   SET_TYPE_VECTOR_SUBPARTS (t, nunits);
6420   TYPE_MODE (t) = mode;
6421   TYPE_READONLY (t) = TYPE_READONLY (innertype);
6422   TYPE_VOLATILE (t) = TYPE_VOLATILE (innertype);
6423
6424   layout_type (t);
6425
6426   {
6427     tree index = build_int_cst (NULL_TREE, nunits - 1);
6428     tree array = build_array_type (innertype, build_index_type (index));
6429     tree rt = make_node (RECORD_TYPE);
6430
6431     TYPE_FIELDS (rt) = build_decl (FIELD_DECL, get_identifier ("f"), array);
6432     DECL_CONTEXT (TYPE_FIELDS (rt)) = rt;
6433     layout_type (rt);
6434     TYPE_DEBUG_REPRESENTATION_TYPE (t) = rt;
6435     /* In dwarfout.c, type lookup uses TYPE_UID numbers.  We want to output
6436        the representation type, and we want to find that die when looking up
6437        the vector type.  This is most easily achieved by making the TYPE_UID
6438        numbers equal.  */
6439     TYPE_UID (rt) = TYPE_UID (t);
6440   }
6441
6442   /* Build our main variant, based on the main variant of the inner type.  */
6443   if (TYPE_MAIN_VARIANT (innertype) != innertype)
6444     {
6445       tree innertype_main_variant = TYPE_MAIN_VARIANT (innertype);
6446       unsigned int hash = TYPE_HASH (innertype_main_variant);
6447       TYPE_MAIN_VARIANT (t)
6448         = type_hash_canon (hash, make_vector_type (innertype_main_variant,
6449                                                    nunits, mode));
6450     }
6451
6452   return t;
6453 }
6454
6455 static tree
6456 make_or_reuse_type (unsigned size, int unsignedp)
6457 {
6458   if (size == INT_TYPE_SIZE)
6459     return unsignedp ? unsigned_type_node : integer_type_node;
6460   if (size == CHAR_TYPE_SIZE)
6461     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
6462   if (size == SHORT_TYPE_SIZE)
6463     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
6464   if (size == LONG_TYPE_SIZE)
6465     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
6466   if (size == LONG_LONG_TYPE_SIZE)
6467     return (unsignedp ? long_long_unsigned_type_node
6468             : long_long_integer_type_node);
6469
6470   if (unsignedp)
6471     return make_unsigned_type (size);
6472   else
6473     return make_signed_type (size);
6474 }
6475
6476 /* Create nodes for all integer types (and error_mark_node) using the sizes
6477    of C datatypes.  The caller should call set_sizetype soon after calling
6478    this function to select one of the types as sizetype.  */
6479
6480 void
6481 build_common_tree_nodes (bool signed_char, bool signed_sizetype)
6482 {
6483   error_mark_node = make_node (ERROR_MARK);
6484   TREE_TYPE (error_mark_node) = error_mark_node;
6485
6486   initialize_sizetypes (signed_sizetype);
6487
6488   /* Define both `signed char' and `unsigned char'.  */
6489   signed_char_type_node = make_signed_type (CHAR_TYPE_SIZE);
6490   TYPE_STRING_FLAG (signed_char_type_node) = 1;
6491   unsigned_char_type_node = make_unsigned_type (CHAR_TYPE_SIZE);
6492   TYPE_STRING_FLAG (unsigned_char_type_node) = 1;
6493
6494   /* Define `char', which is like either `signed char' or `unsigned char'
6495      but not the same as either.  */
6496   char_type_node
6497     = (signed_char
6498        ? make_signed_type (CHAR_TYPE_SIZE)
6499        : make_unsigned_type (CHAR_TYPE_SIZE));
6500   TYPE_STRING_FLAG (char_type_node) = 1;
6501
6502   short_integer_type_node = make_signed_type (SHORT_TYPE_SIZE);
6503   short_unsigned_type_node = make_unsigned_type (SHORT_TYPE_SIZE);
6504   integer_type_node = make_signed_type (INT_TYPE_SIZE);
6505   unsigned_type_node = make_unsigned_type (INT_TYPE_SIZE);
6506   long_integer_type_node = make_signed_type (LONG_TYPE_SIZE);
6507   long_unsigned_type_node = make_unsigned_type (LONG_TYPE_SIZE);
6508   long_long_integer_type_node = make_signed_type (LONG_LONG_TYPE_SIZE);
6509   long_long_unsigned_type_node = make_unsigned_type (LONG_LONG_TYPE_SIZE);
6510
6511   /* Define a boolean type.  This type only represents boolean values but
6512      may be larger than char depending on the value of BOOL_TYPE_SIZE.
6513      Front ends which want to override this size (i.e. Java) can redefine
6514      boolean_type_node before calling build_common_tree_nodes_2.  */
6515   boolean_type_node = make_unsigned_type (BOOL_TYPE_SIZE);
6516   TREE_SET_CODE (boolean_type_node, BOOLEAN_TYPE);
6517   TYPE_MAX_VALUE (boolean_type_node) = build_int_cst (boolean_type_node, 1);
6518   TYPE_PRECISION (boolean_type_node) = 1;
6519
6520   /* Fill in the rest of the sized types.  Reuse existing type nodes
6521      when possible.  */
6522   intQI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (QImode), 0);
6523   intHI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (HImode), 0);
6524   intSI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (SImode), 0);
6525   intDI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (DImode), 0);
6526   intTI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (TImode), 0);
6527
6528   unsigned_intQI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (QImode), 1);
6529   unsigned_intHI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (HImode), 1);
6530   unsigned_intSI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (SImode), 1);
6531   unsigned_intDI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (DImode), 1);
6532   unsigned_intTI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (TImode), 1);
6533
6534   access_public_node = get_identifier ("public");
6535   access_protected_node = get_identifier ("protected");
6536   access_private_node = get_identifier ("private");
6537 }
6538
6539 /* Call this function after calling build_common_tree_nodes and set_sizetype.
6540    It will create several other common tree nodes.  */
6541
6542 void
6543 build_common_tree_nodes_2 (int short_double)
6544 {
6545   /* Define these next since types below may used them.  */
6546   integer_zero_node = build_int_cst (NULL_TREE, 0);
6547   integer_one_node = build_int_cst (NULL_TREE, 1);
6548   integer_minus_one_node = build_int_cst (NULL_TREE, -1);
6549
6550   size_zero_node = size_int (0);
6551   size_one_node = size_int (1);
6552   bitsize_zero_node = bitsize_int (0);
6553   bitsize_one_node = bitsize_int (1);
6554   bitsize_unit_node = bitsize_int (BITS_PER_UNIT);
6555
6556   boolean_false_node = TYPE_MIN_VALUE (boolean_type_node);
6557   boolean_true_node = TYPE_MAX_VALUE (boolean_type_node);
6558
6559   void_type_node = make_node (VOID_TYPE);
6560   layout_type (void_type_node);
6561
6562   /* We are not going to have real types in C with less than byte alignment,
6563      so we might as well not have any types that claim to have it.  */
6564   TYPE_ALIGN (void_type_node) = BITS_PER_UNIT;
6565   TYPE_USER_ALIGN (void_type_node) = 0;
6566
6567   null_pointer_node = build_int_cst (build_pointer_type (void_type_node), 0);
6568   layout_type (TREE_TYPE (null_pointer_node));
6569
6570   ptr_type_node = build_pointer_type (void_type_node);
6571   const_ptr_type_node
6572     = build_pointer_type (build_type_variant (void_type_node, 1, 0));
6573   fileptr_type_node = ptr_type_node;
6574
6575   float_type_node = make_node (REAL_TYPE);
6576   TYPE_PRECISION (float_type_node) = FLOAT_TYPE_SIZE;
6577   layout_type (float_type_node);
6578
6579   double_type_node = make_node (REAL_TYPE);
6580   if (short_double)
6581     TYPE_PRECISION (double_type_node) = FLOAT_TYPE_SIZE;
6582   else
6583     TYPE_PRECISION (double_type_node) = DOUBLE_TYPE_SIZE;
6584   layout_type (double_type_node);
6585
6586   long_double_type_node = make_node (REAL_TYPE);
6587   TYPE_PRECISION (long_double_type_node) = LONG_DOUBLE_TYPE_SIZE;
6588   layout_type (long_double_type_node);
6589
6590   float_ptr_type_node = build_pointer_type (float_type_node);
6591   double_ptr_type_node = build_pointer_type (double_type_node);
6592   long_double_ptr_type_node = build_pointer_type (long_double_type_node);
6593   integer_ptr_type_node = build_pointer_type (integer_type_node);
6594
6595   /* Decimal float types. */
6596   dfloat32_type_node = make_node (REAL_TYPE);
6597   TYPE_PRECISION (dfloat32_type_node) = DECIMAL32_TYPE_SIZE;
6598   layout_type (dfloat32_type_node);
6599   TYPE_MODE (dfloat32_type_node) = SDmode;
6600   dfloat32_ptr_type_node = build_pointer_type (dfloat32_type_node);
6601
6602   dfloat64_type_node = make_node (REAL_TYPE);
6603   TYPE_PRECISION (dfloat64_type_node) = DECIMAL64_TYPE_SIZE;
6604   layout_type (dfloat64_type_node);
6605   TYPE_MODE (dfloat64_type_node) = DDmode;
6606   dfloat64_ptr_type_node = build_pointer_type (dfloat64_type_node);
6607
6608   dfloat128_type_node = make_node (REAL_TYPE);
6609   TYPE_PRECISION (dfloat128_type_node) = DECIMAL128_TYPE_SIZE;
6610   layout_type (dfloat128_type_node);
6611   TYPE_MODE (dfloat128_type_node) = TDmode;
6612   dfloat128_ptr_type_node = build_pointer_type (dfloat128_type_node);
6613
6614   complex_integer_type_node = make_node (COMPLEX_TYPE);
6615   TREE_TYPE (complex_integer_type_node) = integer_type_node;
6616   layout_type (complex_integer_type_node);
6617
6618   complex_float_type_node = make_node (COMPLEX_TYPE);
6619   TREE_TYPE (complex_float_type_node) = float_type_node;
6620   layout_type (complex_float_type_node);
6621
6622   complex_double_type_node = make_node (COMPLEX_TYPE);
6623   TREE_TYPE (complex_double_type_node) = double_type_node;
6624   layout_type (complex_double_type_node);
6625
6626   complex_long_double_type_node = make_node (COMPLEX_TYPE);
6627   TREE_TYPE (complex_long_double_type_node) = long_double_type_node;
6628   layout_type (complex_long_double_type_node);
6629
6630   {
6631     tree t = targetm.build_builtin_va_list ();
6632
6633     /* Many back-ends define record types without setting TYPE_NAME.
6634        If we copied the record type here, we'd keep the original
6635        record type without a name.  This breaks name mangling.  So,
6636        don't copy record types and let c_common_nodes_and_builtins()
6637        declare the type to be __builtin_va_list.  */
6638     if (TREE_CODE (t) != RECORD_TYPE)
6639       t = build_variant_type_copy (t);
6640
6641     va_list_type_node = t;
6642   }
6643 }
6644
6645 /* A subroutine of build_common_builtin_nodes.  Define a builtin function.  */
6646
6647 static void
6648 local_define_builtin (const char *name, tree type, enum built_in_function code,
6649                       const char *library_name, int ecf_flags)
6650 {
6651   tree decl;
6652
6653   decl = lang_hooks.builtin_function (name, type, code, BUILT_IN_NORMAL,
6654                                       library_name, NULL_TREE);
6655   if (ecf_flags & ECF_CONST)
6656     TREE_READONLY (decl) = 1;
6657   if (ecf_flags & ECF_PURE)
6658     DECL_IS_PURE (decl) = 1;
6659   if (ecf_flags & ECF_NORETURN)
6660     TREE_THIS_VOLATILE (decl) = 1;
6661   if (ecf_flags & ECF_NOTHROW)
6662     TREE_NOTHROW (decl) = 1;
6663   if (ecf_flags & ECF_MALLOC)
6664     DECL_IS_MALLOC (decl) = 1;
6665
6666   built_in_decls[code] = decl;
6667   implicit_built_in_decls[code] = decl;
6668 }
6669
6670 /* Call this function after instantiating all builtins that the language
6671    front end cares about.  This will build the rest of the builtins that
6672    are relied upon by the tree optimizers and the middle-end.  */
6673
6674 void
6675 build_common_builtin_nodes (void)
6676 {
6677   tree tmp, ftype;
6678
6679   if (built_in_decls[BUILT_IN_MEMCPY] == NULL
6680       || built_in_decls[BUILT_IN_MEMMOVE] == NULL)
6681     {
6682       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6683       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6684       tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6685       ftype = build_function_type (ptr_type_node, tmp);
6686
6687       if (built_in_decls[BUILT_IN_MEMCPY] == NULL)
6688         local_define_builtin ("__builtin_memcpy", ftype, BUILT_IN_MEMCPY,
6689                               "memcpy", ECF_NOTHROW);
6690       if (built_in_decls[BUILT_IN_MEMMOVE] == NULL)
6691         local_define_builtin ("__builtin_memmove", ftype, BUILT_IN_MEMMOVE,
6692                               "memmove", ECF_NOTHROW);
6693     }
6694
6695   if (built_in_decls[BUILT_IN_MEMCMP] == NULL)
6696     {
6697       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6698       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6699       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6700       ftype = build_function_type (integer_type_node, tmp);
6701       local_define_builtin ("__builtin_memcmp", ftype, BUILT_IN_MEMCMP,
6702                             "memcmp", ECF_PURE | ECF_NOTHROW);
6703     }
6704
6705   if (built_in_decls[BUILT_IN_MEMSET] == NULL)
6706     {
6707       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6708       tmp = tree_cons (NULL_TREE, integer_type_node, tmp);
6709       tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6710       ftype = build_function_type (ptr_type_node, tmp);
6711       local_define_builtin ("__builtin_memset", ftype, BUILT_IN_MEMSET,
6712                             "memset", ECF_NOTHROW);
6713     }
6714
6715   if (built_in_decls[BUILT_IN_ALLOCA] == NULL)
6716     {
6717       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6718       ftype = build_function_type (ptr_type_node, tmp);
6719       local_define_builtin ("__builtin_alloca", ftype, BUILT_IN_ALLOCA,
6720                             "alloca", ECF_NOTHROW | ECF_MALLOC);
6721     }
6722
6723   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6724   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6725   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6726   ftype = build_function_type (void_type_node, tmp);
6727   local_define_builtin ("__builtin_init_trampoline", ftype,
6728                         BUILT_IN_INIT_TRAMPOLINE,
6729                         "__builtin_init_trampoline", ECF_NOTHROW);
6730
6731   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6732   ftype = build_function_type (ptr_type_node, tmp);
6733   local_define_builtin ("__builtin_adjust_trampoline", ftype,
6734                         BUILT_IN_ADJUST_TRAMPOLINE,
6735                         "__builtin_adjust_trampoline",
6736                         ECF_CONST | ECF_NOTHROW);
6737
6738   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6739   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6740   ftype = build_function_type (void_type_node, tmp);
6741   local_define_builtin ("__builtin_nonlocal_goto", ftype,
6742                         BUILT_IN_NONLOCAL_GOTO,
6743                         "__builtin_nonlocal_goto",
6744                         ECF_NORETURN | ECF_NOTHROW);
6745
6746   ftype = build_function_type (ptr_type_node, void_list_node);
6747   local_define_builtin ("__builtin_stack_save", ftype, BUILT_IN_STACK_SAVE,
6748                         "__builtin_stack_save", ECF_NOTHROW);
6749
6750   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6751   ftype = build_function_type (void_type_node, tmp);
6752   local_define_builtin ("__builtin_stack_restore", ftype,
6753                         BUILT_IN_STACK_RESTORE,
6754                         "__builtin_stack_restore", ECF_NOTHROW);
6755
6756   ftype = build_function_type (void_type_node, void_list_node);
6757   local_define_builtin ("__builtin_profile_func_enter", ftype,
6758                         BUILT_IN_PROFILE_FUNC_ENTER, "profile_func_enter", 0);
6759   local_define_builtin ("__builtin_profile_func_exit", ftype,
6760                         BUILT_IN_PROFILE_FUNC_EXIT, "profile_func_exit", 0);
6761
6762   /* Complex multiplication and division.  These are handled as builtins
6763      rather than optabs because emit_library_call_value doesn't support
6764      complex.  Further, we can do slightly better with folding these
6765      beasties if the real and complex parts of the arguments are separate.  */
6766   {
6767     enum machine_mode mode;
6768
6769     for (mode = MIN_MODE_COMPLEX_FLOAT; mode <= MAX_MODE_COMPLEX_FLOAT; ++mode)
6770       {
6771         char mode_name_buf[4], *q;
6772         const char *p;
6773         enum built_in_function mcode, dcode;
6774         tree type, inner_type;
6775
6776         type = lang_hooks.types.type_for_mode (mode, 0);
6777         if (type == NULL)
6778           continue;
6779         inner_type = TREE_TYPE (type);
6780
6781         tmp = tree_cons (NULL_TREE, inner_type, void_list_node);
6782         tmp = tree_cons (NULL_TREE, inner_type, tmp);
6783         tmp = tree_cons (NULL_TREE, inner_type, tmp);
6784         tmp = tree_cons (NULL_TREE, inner_type, tmp);
6785         ftype = build_function_type (type, tmp);
6786
6787         mcode = BUILT_IN_COMPLEX_MUL_MIN + mode - MIN_MODE_COMPLEX_FLOAT;
6788         dcode = BUILT_IN_COMPLEX_DIV_MIN + mode - MIN_MODE_COMPLEX_FLOAT;
6789
6790         for (p = GET_MODE_NAME (mode), q = mode_name_buf; *p; p++, q++)
6791           *q = TOLOWER (*p);
6792         *q = '\0';
6793
6794         built_in_names[mcode] = concat ("__mul", mode_name_buf, "3", NULL);
6795         local_define_builtin (built_in_names[mcode], ftype, mcode,
6796                               built_in_names[mcode], ECF_CONST | ECF_NOTHROW);
6797
6798         built_in_names[dcode] = concat ("__div", mode_name_buf, "3", NULL);
6799         local_define_builtin (built_in_names[dcode], ftype, dcode,
6800                               built_in_names[dcode], ECF_CONST | ECF_NOTHROW);
6801       }
6802   }
6803 }
6804
6805 /* HACK.  GROSS.  This is absolutely disgusting.  I wish there was a
6806    better way.
6807
6808    If we requested a pointer to a vector, build up the pointers that
6809    we stripped off while looking for the inner type.  Similarly for
6810    return values from functions.
6811
6812    The argument TYPE is the top of the chain, and BOTTOM is the
6813    new type which we will point to.  */
6814
6815 tree
6816 reconstruct_complex_type (tree type, tree bottom)
6817 {
6818   tree inner, outer;
6819
6820   if (POINTER_TYPE_P (type))
6821     {
6822       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6823       outer = build_pointer_type (inner);
6824     }
6825   else if (TREE_CODE (type) == ARRAY_TYPE)
6826     {
6827       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6828       outer = build_array_type (inner, TYPE_DOMAIN (type));
6829     }
6830   else if (TREE_CODE (type) == FUNCTION_TYPE)
6831     {
6832       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6833       outer = build_function_type (inner, TYPE_ARG_TYPES (type));
6834     }
6835   else if (TREE_CODE (type) == METHOD_TYPE)
6836     {
6837       tree argtypes;
6838       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6839       /* The build_method_type_directly() routine prepends 'this' to argument list,
6840          so we must compensate by getting rid of it.  */
6841       argtypes = TYPE_ARG_TYPES (type);
6842       outer = build_method_type_directly (TYPE_METHOD_BASETYPE (type),
6843                                           inner,
6844                                           TYPE_ARG_TYPES (type));
6845       TYPE_ARG_TYPES (outer) = argtypes;
6846     }
6847   else
6848     return bottom;
6849
6850   TYPE_READONLY (outer) = TYPE_READONLY (type);
6851   TYPE_VOLATILE (outer) = TYPE_VOLATILE (type);
6852
6853   return outer;
6854 }
6855
6856 /* Returns a vector tree node given a mode (integer, vector, or BLKmode) and
6857    the inner type.  */
6858 tree
6859 build_vector_type_for_mode (tree innertype, enum machine_mode mode)
6860 {
6861   int nunits;
6862
6863   switch (GET_MODE_CLASS (mode))
6864     {
6865     case MODE_VECTOR_INT:
6866     case MODE_VECTOR_FLOAT:
6867       nunits = GET_MODE_NUNITS (mode);
6868       break;
6869
6870     case MODE_INT:
6871       /* Check that there are no leftover bits.  */
6872       gcc_assert (GET_MODE_BITSIZE (mode)
6873                   % TREE_INT_CST_LOW (TYPE_SIZE (innertype)) == 0);
6874
6875       nunits = GET_MODE_BITSIZE (mode)
6876                / TREE_INT_CST_LOW (TYPE_SIZE (innertype));
6877       break;
6878
6879     default:
6880       gcc_unreachable ();
6881     }
6882
6883   return make_vector_type (innertype, nunits, mode);
6884 }
6885
6886 /* Similarly, but takes the inner type and number of units, which must be
6887    a power of two.  */
6888
6889 tree
6890 build_vector_type (tree innertype, int nunits)
6891 {
6892   return make_vector_type (innertype, nunits, VOIDmode);
6893 }
6894
6895 /* Build RESX_EXPR with given REGION_NUMBER.  */
6896 tree
6897 build_resx (int region_number)
6898 {
6899   tree t;
6900   t = build1 (RESX_EXPR, void_type_node,
6901               build_int_cst (NULL_TREE, region_number));
6902   return t;
6903 }
6904
6905 /* Given an initializer INIT, return TRUE if INIT is zero or some
6906    aggregate of zeros.  Otherwise return FALSE.  */
6907 bool
6908 initializer_zerop (tree init)
6909 {
6910   tree elt;
6911
6912   STRIP_NOPS (init);
6913
6914   switch (TREE_CODE (init))
6915     {
6916     case INTEGER_CST:
6917       return integer_zerop (init);
6918
6919     case REAL_CST:
6920       /* ??? Note that this is not correct for C4X float formats.  There,
6921          a bit pattern of all zeros is 1.0; 0.0 is encoded with the most
6922          negative exponent.  */
6923       return real_zerop (init)
6924         && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (init));
6925
6926     case COMPLEX_CST:
6927       return integer_zerop (init)
6928         || (real_zerop (init)
6929             && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_REALPART (init)))
6930             && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_IMAGPART (init))));
6931
6932     case VECTOR_CST:
6933       for (elt = TREE_VECTOR_CST_ELTS (init); elt; elt = TREE_CHAIN (elt))
6934         if (!initializer_zerop (TREE_VALUE (elt)))
6935           return false;
6936       return true;
6937
6938     case CONSTRUCTOR:
6939       {
6940         unsigned HOST_WIDE_INT idx;
6941
6942         FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), idx, elt)
6943           if (!initializer_zerop (elt))
6944             return false;
6945         return true;
6946       }
6947
6948     default:
6949       return false;
6950     }
6951 }
6952
6953 /* Build an empty statement.  */
6954
6955 tree
6956 build_empty_stmt (void)
6957 {
6958   return build1 (NOP_EXPR, void_type_node, size_zero_node);
6959 }
6960
6961
6962 /* Build an OpenMP clause with code CODE.  */
6963
6964 tree
6965 build_omp_clause (enum omp_clause_code code)
6966 {
6967   tree t;
6968   int size, length;
6969
6970   length = omp_clause_num_ops[code];
6971   size = (sizeof (struct tree_omp_clause) + (length - 1) * sizeof (tree));
6972
6973   t = ggc_alloc (size);
6974   memset (t, 0, size);
6975   TREE_SET_CODE (t, OMP_CLAUSE);
6976   OMP_CLAUSE_SET_CODE (t, code);
6977
6978 #ifdef GATHER_STATISTICS
6979   tree_node_counts[(int) omp_clause_kind]++;
6980   tree_node_sizes[(int) omp_clause_kind] += size;
6981 #endif
6982
6983   return t;
6984 }
6985
6986
6987 /* Returns true if it is possible to prove that the index of
6988    an array access REF (an ARRAY_REF expression) falls into the
6989    array bounds.  */
6990
6991 bool
6992 in_array_bounds_p (tree ref)
6993 {
6994   tree idx = TREE_OPERAND (ref, 1);
6995   tree min, max;
6996
6997   if (TREE_CODE (idx) != INTEGER_CST)
6998     return false;
6999
7000   min = array_ref_low_bound (ref);
7001   max = array_ref_up_bound (ref);
7002   if (!min
7003       || !max
7004       || TREE_CODE (min) != INTEGER_CST
7005       || TREE_CODE (max) != INTEGER_CST)
7006     return false;
7007
7008   if (tree_int_cst_lt (idx, min)
7009       || tree_int_cst_lt (max, idx))
7010     return false;
7011
7012   return true;
7013 }
7014
7015 /* Returns true if it is possible to prove that the range of
7016    an array access REF (an ARRAY_RANGE_REF expression) falls
7017    into the array bounds.  */
7018
7019 bool
7020 range_in_array_bounds_p (tree ref)
7021 {
7022   tree domain_type = TYPE_DOMAIN (TREE_TYPE (ref));
7023   tree range_min, range_max, min, max;
7024
7025   range_min = TYPE_MIN_VALUE (domain_type);
7026   range_max = TYPE_MAX_VALUE (domain_type);
7027   if (!range_min
7028       || !range_max
7029       || TREE_CODE (range_min) != INTEGER_CST
7030       || TREE_CODE (range_max) != INTEGER_CST)
7031     return false;
7032
7033   min = array_ref_low_bound (ref);
7034   max = array_ref_up_bound (ref);
7035   if (!min
7036       || !max
7037       || TREE_CODE (min) != INTEGER_CST
7038       || TREE_CODE (max) != INTEGER_CST)
7039     return false;
7040
7041   if (tree_int_cst_lt (range_min, min)
7042       || tree_int_cst_lt (max, range_max))
7043     return false;
7044
7045   return true;
7046 }
7047
7048 /* Return true if T (assumed to be a DECL) is a global variable.  */
7049
7050 bool
7051 is_global_var (tree t)
7052 {
7053   if (MTAG_P (t))
7054     return (TREE_STATIC (t) || MTAG_GLOBAL (t));
7055   else
7056     return (TREE_STATIC (t) || DECL_EXTERNAL (t));
7057 }
7058
7059 /* Return true if T (assumed to be a DECL) must be assigned a memory
7060    location.  */
7061
7062 bool
7063 needs_to_live_in_memory (tree t)
7064 {
7065   return (TREE_ADDRESSABLE (t)
7066           || is_global_var (t)
7067           || (TREE_CODE (t) == RESULT_DECL
7068               && aggregate_value_p (t, current_function_decl)));
7069 }
7070
7071 /* There are situations in which a language considers record types
7072    compatible which have different field lists.  Decide if two fields
7073    are compatible.  It is assumed that the parent records are compatible.  */
7074
7075 bool
7076 fields_compatible_p (tree f1, tree f2)
7077 {
7078   if (!operand_equal_p (DECL_FIELD_BIT_OFFSET (f1),
7079                         DECL_FIELD_BIT_OFFSET (f2), OEP_ONLY_CONST))
7080     return false;
7081
7082   if (!operand_equal_p (DECL_FIELD_OFFSET (f1),
7083                         DECL_FIELD_OFFSET (f2), OEP_ONLY_CONST))
7084     return false;
7085
7086   if (!lang_hooks.types_compatible_p (TREE_TYPE (f1), TREE_TYPE (f2)))
7087     return false;
7088
7089   return true;
7090 }
7091
7092 /* Locate within RECORD a field that is compatible with ORIG_FIELD.  */
7093
7094 tree
7095 find_compatible_field (tree record, tree orig_field)
7096 {
7097   tree f;
7098
7099   for (f = TYPE_FIELDS (record); f ; f = TREE_CHAIN (f))
7100     if (TREE_CODE (f) == FIELD_DECL
7101         && fields_compatible_p (f, orig_field))
7102       return f;
7103
7104   /* ??? Why isn't this on the main fields list?  */
7105   f = TYPE_VFIELD (record);
7106   if (f && TREE_CODE (f) == FIELD_DECL
7107       && fields_compatible_p (f, orig_field))
7108     return f;
7109
7110   /* ??? We should abort here, but Java appears to do Bad Things
7111      with inherited fields.  */
7112   return orig_field;
7113 }
7114
7115 /* Return value of a constant X.  */
7116
7117 HOST_WIDE_INT
7118 int_cst_value (tree x)
7119 {
7120   unsigned bits = TYPE_PRECISION (TREE_TYPE (x));
7121   unsigned HOST_WIDE_INT val = TREE_INT_CST_LOW (x);
7122   bool negative = ((val >> (bits - 1)) & 1) != 0;
7123
7124   gcc_assert (bits <= HOST_BITS_PER_WIDE_INT);
7125
7126   if (negative)
7127     val |= (~(unsigned HOST_WIDE_INT) 0) << (bits - 1) << 1;
7128   else
7129     val &= ~((~(unsigned HOST_WIDE_INT) 0) << (bits - 1) << 1);
7130
7131   return val;
7132 }
7133
7134 /* Returns the greatest common divisor of A and B, which must be
7135    INTEGER_CSTs.  */
7136
7137 tree
7138 tree_fold_gcd (tree a, tree b)
7139 {
7140   tree a_mod_b;
7141   tree type = TREE_TYPE (a);
7142
7143   gcc_assert (TREE_CODE (a) == INTEGER_CST);
7144   gcc_assert (TREE_CODE (b) == INTEGER_CST);
7145
7146   if (integer_zerop (a))
7147     return b;
7148
7149   if (integer_zerop (b))
7150     return a;
7151
7152   if (tree_int_cst_sgn (a) == -1)
7153     a = fold_build2 (MULT_EXPR, type, a,
7154                      build_int_cst (type, -1));
7155
7156   if (tree_int_cst_sgn (b) == -1)
7157     b = fold_build2 (MULT_EXPR, type, b,
7158                      build_int_cst (type, -1));
7159
7160   while (1)
7161     {
7162       a_mod_b = fold_build2 (FLOOR_MOD_EXPR, type, a, b);
7163
7164       if (!TREE_INT_CST_LOW (a_mod_b)
7165           && !TREE_INT_CST_HIGH (a_mod_b))
7166         return b;
7167
7168       a = b;
7169       b = a_mod_b;
7170     }
7171 }
7172
7173 /* Returns unsigned variant of TYPE.  */
7174
7175 tree
7176 unsigned_type_for (tree type)
7177 {
7178   if (POINTER_TYPE_P (type))
7179     return lang_hooks.types.unsigned_type (size_type_node);
7180   return lang_hooks.types.unsigned_type (type);
7181 }
7182
7183 /* Returns signed variant of TYPE.  */
7184
7185 tree
7186 signed_type_for (tree type)
7187 {
7188   if (POINTER_TYPE_P (type))
7189     return lang_hooks.types.signed_type (size_type_node);
7190   return lang_hooks.types.signed_type (type);
7191 }
7192
7193 /* Returns the largest value obtainable by casting something in INNER type to
7194    OUTER type.  */
7195
7196 tree
7197 upper_bound_in_type (tree outer, tree inner)
7198 {
7199   unsigned HOST_WIDE_INT lo, hi;
7200   unsigned int det = 0;
7201   unsigned oprec = TYPE_PRECISION (outer);
7202   unsigned iprec = TYPE_PRECISION (inner);
7203   unsigned prec;
7204
7205   /* Compute a unique number for every combination.  */
7206   det |= (oprec > iprec) ? 4 : 0;
7207   det |= TYPE_UNSIGNED (outer) ? 2 : 0;
7208   det |= TYPE_UNSIGNED (inner) ? 1 : 0;
7209
7210   /* Determine the exponent to use.  */
7211   switch (det)
7212     {
7213     case 0:
7214     case 1:
7215       /* oprec <= iprec, outer: signed, inner: don't care.  */
7216       prec = oprec - 1;
7217       break;
7218     case 2:
7219     case 3:
7220       /* oprec <= iprec, outer: unsigned, inner: don't care.  */
7221       prec = oprec;
7222       break;
7223     case 4:
7224       /* oprec > iprec, outer: signed, inner: signed.  */
7225       prec = iprec - 1;
7226       break;
7227     case 5:
7228       /* oprec > iprec, outer: signed, inner: unsigned.  */
7229       prec = iprec;
7230       break;
7231     case 6:
7232       /* oprec > iprec, outer: unsigned, inner: signed.  */
7233       prec = oprec;
7234       break;
7235     case 7:
7236       /* oprec > iprec, outer: unsigned, inner: unsigned.  */
7237       prec = iprec;
7238       break;
7239     default:
7240       gcc_unreachable ();
7241     }
7242
7243   /* Compute 2^^prec - 1.  */
7244   if (prec <= HOST_BITS_PER_WIDE_INT)
7245     {
7246       hi = 0;
7247       lo = ((~(unsigned HOST_WIDE_INT) 0)
7248             >> (HOST_BITS_PER_WIDE_INT - prec));
7249     }
7250   else
7251     {
7252       hi = ((~(unsigned HOST_WIDE_INT) 0)
7253             >> (2 * HOST_BITS_PER_WIDE_INT - prec));
7254       lo = ~(unsigned HOST_WIDE_INT) 0;
7255     }
7256
7257   return build_int_cst_wide (outer, lo, hi);
7258 }
7259
7260 /* Returns the smallest value obtainable by casting something in INNER type to
7261    OUTER type.  */
7262
7263 tree
7264 lower_bound_in_type (tree outer, tree inner)
7265 {
7266   unsigned HOST_WIDE_INT lo, hi;
7267   unsigned oprec = TYPE_PRECISION (outer);
7268   unsigned iprec = TYPE_PRECISION (inner);
7269
7270   /* If OUTER type is unsigned, we can definitely cast 0 to OUTER type
7271      and obtain 0.  */
7272   if (TYPE_UNSIGNED (outer)
7273       /* If we are widening something of an unsigned type, OUTER type
7274          contains all values of INNER type.  In particular, both INNER
7275          and OUTER types have zero in common.  */
7276       || (oprec > iprec && TYPE_UNSIGNED (inner)))
7277     lo = hi = 0;
7278   else
7279     {
7280       /* If we are widening a signed type to another signed type, we
7281          want to obtain -2^^(iprec-1).  If we are keeping the
7282          precision or narrowing to a signed type, we want to obtain
7283          -2^(oprec-1).  */
7284       unsigned prec = oprec > iprec ? iprec : oprec;
7285
7286       if (prec <= HOST_BITS_PER_WIDE_INT)
7287         {
7288           hi = ~(unsigned HOST_WIDE_INT) 0;
7289           lo = (~(unsigned HOST_WIDE_INT) 0) << (prec - 1);
7290         }
7291       else
7292         {
7293           hi = ((~(unsigned HOST_WIDE_INT) 0)
7294                 << (prec - HOST_BITS_PER_WIDE_INT - 1));
7295           lo = 0;
7296         }
7297     }
7298
7299   return build_int_cst_wide (outer, lo, hi);
7300 }
7301
7302 /* Return nonzero if two operands that are suitable for PHI nodes are
7303    necessarily equal.  Specifically, both ARG0 and ARG1 must be either
7304    SSA_NAME or invariant.  Note that this is strictly an optimization.
7305    That is, callers of this function can directly call operand_equal_p
7306    and get the same result, only slower.  */
7307
7308 int
7309 operand_equal_for_phi_arg_p (tree arg0, tree arg1)
7310 {
7311   if (arg0 == arg1)
7312     return 1;
7313   if (TREE_CODE (arg0) == SSA_NAME || TREE_CODE (arg1) == SSA_NAME)
7314     return 0;
7315   return operand_equal_p (arg0, arg1, 0);
7316 }
7317
7318 /* Returns number of zeros at the end of binary representation of X.
7319
7320    ??? Use ffs if available?  */
7321
7322 tree
7323 num_ending_zeros (tree x)
7324 {
7325   unsigned HOST_WIDE_INT fr, nfr;
7326   unsigned num, abits;
7327   tree type = TREE_TYPE (x);
7328
7329   if (TREE_INT_CST_LOW (x) == 0)
7330     {
7331       num = HOST_BITS_PER_WIDE_INT;
7332       fr = TREE_INT_CST_HIGH (x);
7333     }
7334   else
7335     {
7336       num = 0;
7337       fr = TREE_INT_CST_LOW (x);
7338     }
7339
7340   for (abits = HOST_BITS_PER_WIDE_INT / 2; abits; abits /= 2)
7341     {
7342       nfr = fr >> abits;
7343       if (nfr << abits == fr)
7344         {
7345           num += abits;
7346           fr = nfr;
7347         }
7348     }
7349
7350   if (num > TYPE_PRECISION (type))
7351     num = TYPE_PRECISION (type);
7352
7353   return build_int_cst_type (type, num);
7354 }
7355
7356
7357 #define WALK_SUBTREE(NODE)                              \
7358   do                                                    \
7359     {                                                   \
7360       result = walk_tree (&(NODE), func, data, pset);   \
7361       if (result)                                       \
7362         return result;                                  \
7363     }                                                   \
7364   while (0)
7365
7366 /* This is a subroutine of walk_tree that walks field of TYPE that are to
7367    be walked whenever a type is seen in the tree.  Rest of operands and return
7368    value are as for walk_tree.  */
7369
7370 static tree
7371 walk_type_fields (tree type, walk_tree_fn func, void *data,
7372                   struct pointer_set_t *pset)
7373 {
7374   tree result = NULL_TREE;
7375
7376   switch (TREE_CODE (type))
7377     {
7378     case POINTER_TYPE:
7379     case REFERENCE_TYPE:
7380       /* We have to worry about mutually recursive pointers.  These can't
7381          be written in C.  They can in Ada.  It's pathological, but
7382          there's an ACATS test (c38102a) that checks it.  Deal with this
7383          by checking if we're pointing to another pointer, that one
7384          points to another pointer, that one does too, and we have no htab.
7385          If so, get a hash table.  We check three levels deep to avoid
7386          the cost of the hash table if we don't need one.  */
7387       if (POINTER_TYPE_P (TREE_TYPE (type))
7388           && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (type)))
7389           && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (TREE_TYPE (type))))
7390           && !pset)
7391         {
7392           result = walk_tree_without_duplicates (&TREE_TYPE (type),
7393                                                  func, data);
7394           if (result)
7395             return result;
7396
7397           break;
7398         }
7399
7400       /* ... fall through ... */
7401
7402     case COMPLEX_TYPE:
7403       WALK_SUBTREE (TREE_TYPE (type));
7404       break;
7405
7406     case METHOD_TYPE:
7407       WALK_SUBTREE (TYPE_METHOD_BASETYPE (type));
7408
7409       /* Fall through.  */
7410
7411     case FUNCTION_TYPE:
7412       WALK_SUBTREE (TREE_TYPE (type));
7413       {
7414         tree arg;
7415
7416         /* We never want to walk into default arguments.  */
7417         for (arg = TYPE_ARG_TYPES (type); arg; arg = TREE_CHAIN (arg))
7418           WALK_SUBTREE (TREE_VALUE (arg));
7419       }
7420       break;
7421
7422     case ARRAY_TYPE:
7423       /* Don't follow this nodes's type if a pointer for fear that we'll
7424          have infinite recursion.  Those types are uninteresting anyway.  */
7425       if (!POINTER_TYPE_P (TREE_TYPE (type))
7426           && TREE_CODE (TREE_TYPE (type)) != OFFSET_TYPE)
7427         WALK_SUBTREE (TREE_TYPE (type));
7428       WALK_SUBTREE (TYPE_DOMAIN (type));
7429       break;
7430
7431     case BOOLEAN_TYPE:
7432     case ENUMERAL_TYPE:
7433     case INTEGER_TYPE:
7434     case REAL_TYPE:
7435       WALK_SUBTREE (TYPE_MIN_VALUE (type));
7436       WALK_SUBTREE (TYPE_MAX_VALUE (type));
7437       break;
7438
7439     case OFFSET_TYPE:
7440       WALK_SUBTREE (TREE_TYPE (type));
7441       WALK_SUBTREE (TYPE_OFFSET_BASETYPE (type));
7442       break;
7443
7444     default:
7445       break;
7446     }
7447
7448   return NULL_TREE;
7449 }
7450
7451 /* Apply FUNC to all the sub-trees of TP in a pre-order traversal.  FUNC is
7452    called with the DATA and the address of each sub-tree.  If FUNC returns a
7453    non-NULL value, the traversal is stopped, and the value returned by FUNC
7454    is returned.  If PSET is non-NULL it is used to record the nodes visited,
7455    and to avoid visiting a node more than once.  */
7456
7457 tree
7458 walk_tree (tree *tp, walk_tree_fn func, void *data, struct pointer_set_t *pset)
7459 {
7460   enum tree_code code;
7461   int walk_subtrees;
7462   tree result;
7463
7464 #define WALK_SUBTREE_TAIL(NODE)                         \
7465   do                                                    \
7466     {                                                   \
7467        tp = & (NODE);                                   \
7468        goto tail_recurse;                               \
7469     }                                                   \
7470   while (0)
7471
7472  tail_recurse:
7473   /* Skip empty subtrees.  */
7474   if (!*tp)
7475     return NULL_TREE;
7476
7477   /* Don't walk the same tree twice, if the user has requested
7478      that we avoid doing so.  */
7479   if (pset && pointer_set_insert (pset, *tp))
7480     return NULL_TREE;
7481
7482   /* Call the function.  */
7483   walk_subtrees = 1;
7484   result = (*func) (tp, &walk_subtrees, data);
7485
7486   /* If we found something, return it.  */
7487   if (result)
7488     return result;
7489
7490   code = TREE_CODE (*tp);
7491
7492   /* Even if we didn't, FUNC may have decided that there was nothing
7493      interesting below this point in the tree.  */
7494   if (!walk_subtrees)
7495     {
7496       /* But we still need to check our siblings.  */
7497       if (code == TREE_LIST)
7498         WALK_SUBTREE_TAIL (TREE_CHAIN (*tp));
7499       else if (code == OMP_CLAUSE)
7500         WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7501       else
7502         return NULL_TREE;
7503     }
7504
7505   result = lang_hooks.tree_inlining.walk_subtrees (tp, &walk_subtrees, func,
7506                                                    data, pset);
7507   if (result || ! walk_subtrees)
7508     return result;
7509
7510   switch (code)
7511     {
7512     case ERROR_MARK:
7513     case IDENTIFIER_NODE:
7514     case INTEGER_CST:
7515     case REAL_CST:
7516     case VECTOR_CST:
7517     case STRING_CST:
7518     case BLOCK:
7519     case PLACEHOLDER_EXPR:
7520     case SSA_NAME:
7521     case FIELD_DECL:
7522     case RESULT_DECL:
7523       /* None of these have subtrees other than those already walked
7524          above.  */
7525       break;
7526
7527     case TREE_LIST:
7528       WALK_SUBTREE (TREE_VALUE (*tp));
7529       WALK_SUBTREE_TAIL (TREE_CHAIN (*tp));
7530       break;
7531
7532     case TREE_VEC:
7533       {
7534         int len = TREE_VEC_LENGTH (*tp);
7535
7536         if (len == 0)
7537           break;
7538
7539         /* Walk all elements but the first.  */
7540         while (--len)
7541           WALK_SUBTREE (TREE_VEC_ELT (*tp, len));
7542
7543         /* Now walk the first one as a tail call.  */
7544         WALK_SUBTREE_TAIL (TREE_VEC_ELT (*tp, 0));
7545       }
7546
7547     case COMPLEX_CST:
7548       WALK_SUBTREE (TREE_REALPART (*tp));
7549       WALK_SUBTREE_TAIL (TREE_IMAGPART (*tp));
7550
7551     case CONSTRUCTOR:
7552       {
7553         unsigned HOST_WIDE_INT idx;
7554         constructor_elt *ce;
7555
7556         for (idx = 0;
7557              VEC_iterate(constructor_elt, CONSTRUCTOR_ELTS (*tp), idx, ce);
7558              idx++)
7559           WALK_SUBTREE (ce->value);
7560       }
7561       break;
7562
7563     case SAVE_EXPR:
7564       WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, 0));
7565
7566     case BIND_EXPR:
7567       {
7568         tree decl;
7569         for (decl = BIND_EXPR_VARS (*tp); decl; decl = TREE_CHAIN (decl))
7570           {
7571             /* Walk the DECL_INITIAL and DECL_SIZE.  We don't want to walk
7572                into declarations that are just mentioned, rather than
7573                declared; they don't really belong to this part of the tree.
7574                And, we can see cycles: the initializer for a declaration
7575                can refer to the declaration itself.  */
7576             WALK_SUBTREE (DECL_INITIAL (decl));
7577             WALK_SUBTREE (DECL_SIZE (decl));
7578             WALK_SUBTREE (DECL_SIZE_UNIT (decl));
7579           }
7580         WALK_SUBTREE_TAIL (BIND_EXPR_BODY (*tp));
7581       }
7582
7583     case STATEMENT_LIST:
7584       {
7585         tree_stmt_iterator i;
7586         for (i = tsi_start (*tp); !tsi_end_p (i); tsi_next (&i))
7587           WALK_SUBTREE (*tsi_stmt_ptr (i));
7588       }
7589       break;
7590
7591     case OMP_CLAUSE:
7592       switch (OMP_CLAUSE_CODE (*tp))
7593         {
7594         case OMP_CLAUSE_PRIVATE:
7595         case OMP_CLAUSE_SHARED:
7596         case OMP_CLAUSE_FIRSTPRIVATE:
7597         case OMP_CLAUSE_LASTPRIVATE:
7598         case OMP_CLAUSE_COPYIN:
7599         case OMP_CLAUSE_COPYPRIVATE:
7600         case OMP_CLAUSE_IF:
7601         case OMP_CLAUSE_NUM_THREADS:
7602         case OMP_CLAUSE_SCHEDULE:
7603           WALK_SUBTREE (OMP_CLAUSE_OPERAND (*tp, 0));
7604           /* FALLTHRU */
7605
7606         case OMP_CLAUSE_NOWAIT:
7607         case OMP_CLAUSE_ORDERED:
7608         case OMP_CLAUSE_DEFAULT:
7609           WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7610
7611         case OMP_CLAUSE_REDUCTION:
7612           {
7613             int i;
7614             for (i = 0; i < 4; i++)
7615               WALK_SUBTREE (OMP_CLAUSE_OPERAND (*tp, i));
7616             WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7617           }
7618
7619         default:
7620           gcc_unreachable ();
7621         }
7622       break;
7623
7624     case TARGET_EXPR:
7625       {
7626         int i, len;
7627
7628         /* TARGET_EXPRs are peculiar: operands 1 and 3 can be the same.
7629            But, we only want to walk once.  */
7630         len = (TREE_OPERAND (*tp, 3) == TREE_OPERAND (*tp, 1)) ? 2 : 3;
7631         for (i = 0; i < len; ++i)
7632           WALK_SUBTREE (TREE_OPERAND (*tp, i));
7633         WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, len));
7634       }
7635
7636     case DECL_EXPR:
7637       /* Walk into various fields of the type that it's defining.  We only
7638          want to walk into these fields of a type in this case.  Note that
7639          decls get walked as part of the processing of a BIND_EXPR.
7640
7641          ??? Precisely which fields of types that we are supposed to walk in
7642          this case vs. the normal case aren't well defined.  */
7643       if (TREE_CODE (DECL_EXPR_DECL (*tp)) == TYPE_DECL
7644           && TREE_CODE (TREE_TYPE (DECL_EXPR_DECL (*tp))) != ERROR_MARK)
7645         {
7646           tree *type_p = &TREE_TYPE (DECL_EXPR_DECL (*tp));
7647
7648           /* Call the function for the type.  See if it returns anything or
7649              doesn't want us to continue.  If we are to continue, walk both
7650              the normal fields and those for the declaration case.  */
7651           result = (*func) (type_p, &walk_subtrees, data);
7652           if (result || !walk_subtrees)
7653             return NULL_TREE;
7654
7655           result = walk_type_fields (*type_p, func, data, pset);
7656           if (result)
7657             return result;
7658
7659           /* If this is a record type, also walk the fields.  */
7660           if (TREE_CODE (*type_p) == RECORD_TYPE
7661               || TREE_CODE (*type_p) == UNION_TYPE
7662               || TREE_CODE (*type_p) == QUAL_UNION_TYPE)
7663             {
7664               tree field;
7665
7666               for (field = TYPE_FIELDS (*type_p); field;
7667                    field = TREE_CHAIN (field))
7668                 {
7669                   /* We'd like to look at the type of the field, but we can
7670                      easily get infinite recursion.  So assume it's pointed
7671                      to elsewhere in the tree.  Also, ignore things that
7672                      aren't fields.  */
7673                   if (TREE_CODE (field) != FIELD_DECL)
7674                     continue;
7675
7676                   WALK_SUBTREE (DECL_FIELD_OFFSET (field));
7677                   WALK_SUBTREE (DECL_SIZE (field));
7678                   WALK_SUBTREE (DECL_SIZE_UNIT (field));
7679                   if (TREE_CODE (*type_p) == QUAL_UNION_TYPE)
7680                     WALK_SUBTREE (DECL_QUALIFIER (field));
7681                 }
7682             }
7683
7684           WALK_SUBTREE (TYPE_SIZE (*type_p));
7685           WALK_SUBTREE_TAIL (TYPE_SIZE_UNIT (*type_p));
7686         }
7687       /* FALLTHRU */
7688
7689     default:
7690       if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
7691         {
7692           int i, len;
7693
7694           /* Walk over all the sub-trees of this operand.  */
7695           len = TREE_CODE_LENGTH (code);
7696
7697           /* Go through the subtrees.  We need to do this in forward order so
7698              that the scope of a FOR_EXPR is handled properly.  */
7699           if (len)
7700             {
7701               for (i = 0; i < len - 1; ++i)
7702                 WALK_SUBTREE (TREE_OPERAND (*tp, i));
7703               WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, len - 1));
7704             }
7705         }
7706
7707       /* If this is a type, walk the needed fields in the type.  */
7708       else if (TYPE_P (*tp))
7709         return walk_type_fields (*tp, func, data, pset);
7710       break;
7711     }
7712
7713   /* We didn't find what we were looking for.  */
7714   return NULL_TREE;
7715
7716 #undef WALK_SUBTREE_TAIL
7717 }
7718 #undef WALK_SUBTREE
7719
7720 /* Like walk_tree, but does not walk duplicate nodes more than once.  */
7721
7722 tree
7723 walk_tree_without_duplicates (tree *tp, walk_tree_fn func, void *data)
7724 {
7725   tree result;
7726   struct pointer_set_t *pset;
7727
7728   pset = pointer_set_create ();
7729   result = walk_tree (tp, func, data, pset);
7730   pointer_set_destroy (pset);
7731   return result;
7732 }
7733
7734
7735 /* Return true if STMT is an empty statement or contains nothing but
7736    empty statements.  */
7737
7738 bool
7739 empty_body_p (tree stmt)
7740 {
7741   tree_stmt_iterator i;
7742   tree body;
7743
7744   if (IS_EMPTY_STMT (stmt))
7745     return true;
7746   else if (TREE_CODE (stmt) == BIND_EXPR)
7747     body = BIND_EXPR_BODY (stmt);
7748   else if (TREE_CODE (stmt) == STATEMENT_LIST)
7749     body = stmt;
7750   else
7751     return false;
7752
7753   for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i))
7754     if (!empty_body_p (tsi_stmt (i)))
7755       return false;
7756
7757   return true;
7758 }
7759
7760 #include "gt-tree.h"