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
2927           && node && !TYPE_P (node)
2928           && TREE_CONSTANT (node))
2929         TREE_CONSTANT (t) = 1;
2930       if (TREE_CODE_CLASS (code) == tcc_unary
2931           && node && TREE_INVARIANT (node))
2932         TREE_INVARIANT (t) = 1;
2933       if (TREE_CODE_CLASS (code) == tcc_reference
2934           && node && TREE_THIS_VOLATILE (node))
2935         TREE_THIS_VOLATILE (t) = 1;
2936       break;
2937     }
2938
2939   return t;
2940 }
2941
2942 #define PROCESS_ARG(N)                  \
2943   do {                                  \
2944     TREE_OPERAND (t, N) = arg##N;       \
2945     if (arg##N &&!TYPE_P (arg##N))      \
2946       {                                 \
2947         if (TREE_SIDE_EFFECTS (arg##N)) \
2948           side_effects = 1;             \
2949         if (!TREE_READONLY (arg##N))    \
2950           read_only = 0;                \
2951         if (!TREE_CONSTANT (arg##N))    \
2952           constant = 0;                 \
2953         if (!TREE_INVARIANT (arg##N))   \
2954           invariant = 0;                \
2955       }                                 \
2956   } while (0)
2957
2958 tree
2959 build2_stat (enum tree_code code, tree tt, tree arg0, tree arg1 MEM_STAT_DECL)
2960 {
2961   bool constant, read_only, side_effects, invariant;
2962   tree t;
2963
2964   gcc_assert (TREE_CODE_LENGTH (code) == 2);
2965
2966   t = make_node_stat (code PASS_MEM_STAT);
2967   TREE_TYPE (t) = tt;
2968
2969   /* Below, we automatically set TREE_SIDE_EFFECTS and TREE_READONLY for the
2970      result based on those same flags for the arguments.  But if the
2971      arguments aren't really even `tree' expressions, we shouldn't be trying
2972      to do this.  */
2973
2974   /* Expressions without side effects may be constant if their
2975      arguments are as well.  */
2976   constant = (TREE_CODE_CLASS (code) == tcc_comparison
2977               || TREE_CODE_CLASS (code) == tcc_binary);
2978   read_only = 1;
2979   side_effects = TREE_SIDE_EFFECTS (t);
2980   invariant = constant;
2981
2982   PROCESS_ARG(0);
2983   PROCESS_ARG(1);
2984
2985   TREE_READONLY (t) = read_only;
2986   TREE_CONSTANT (t) = constant;
2987   TREE_INVARIANT (t) = invariant;
2988   TREE_SIDE_EFFECTS (t) = side_effects;
2989   TREE_THIS_VOLATILE (t)
2990     = (TREE_CODE_CLASS (code) == tcc_reference
2991        && arg0 && TREE_THIS_VOLATILE (arg0));
2992
2993   return t;
2994 }
2995
2996 tree
2997 build3_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
2998              tree arg2 MEM_STAT_DECL)
2999 {
3000   bool constant, read_only, side_effects, invariant;
3001   tree t;
3002
3003   gcc_assert (TREE_CODE_LENGTH (code) == 3);
3004
3005   t = make_node_stat (code PASS_MEM_STAT);
3006   TREE_TYPE (t) = tt;
3007
3008   side_effects = TREE_SIDE_EFFECTS (t);
3009
3010   PROCESS_ARG(0);
3011   PROCESS_ARG(1);
3012   PROCESS_ARG(2);
3013
3014   if (code == CALL_EXPR && !side_effects)
3015     {
3016       tree node;
3017       int i;
3018
3019       /* Calls have side-effects, except those to const or
3020          pure functions.  */
3021       i = call_expr_flags (t);
3022       if (!(i & (ECF_CONST | ECF_PURE)))
3023         side_effects = 1;
3024
3025       /* And even those have side-effects if their arguments do.  */
3026       else for (node = arg1; node; node = TREE_CHAIN (node))
3027         if (TREE_SIDE_EFFECTS (TREE_VALUE (node)))
3028           {
3029             side_effects = 1;
3030             break;
3031           }
3032     }
3033
3034   TREE_SIDE_EFFECTS (t) = side_effects;
3035   TREE_THIS_VOLATILE (t)
3036     = (TREE_CODE_CLASS (code) == tcc_reference
3037        && arg0 && TREE_THIS_VOLATILE (arg0));
3038
3039   return t;
3040 }
3041
3042 tree
3043 build4_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3044              tree arg2, tree arg3 MEM_STAT_DECL)
3045 {
3046   bool constant, read_only, side_effects, invariant;
3047   tree t;
3048
3049   gcc_assert (TREE_CODE_LENGTH (code) == 4);
3050
3051   t = make_node_stat (code PASS_MEM_STAT);
3052   TREE_TYPE (t) = tt;
3053
3054   side_effects = TREE_SIDE_EFFECTS (t);
3055
3056   PROCESS_ARG(0);
3057   PROCESS_ARG(1);
3058   PROCESS_ARG(2);
3059   PROCESS_ARG(3);
3060
3061   TREE_SIDE_EFFECTS (t) = side_effects;
3062   TREE_THIS_VOLATILE (t)
3063     = (TREE_CODE_CLASS (code) == tcc_reference
3064        && arg0 && TREE_THIS_VOLATILE (arg0));
3065
3066   return t;
3067 }
3068
3069 tree
3070 build5_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3071              tree arg2, tree arg3, tree arg4 MEM_STAT_DECL)
3072 {
3073   bool constant, read_only, side_effects, invariant;
3074   tree t;
3075
3076   gcc_assert (TREE_CODE_LENGTH (code) == 5);
3077
3078   t = make_node_stat (code PASS_MEM_STAT);
3079   TREE_TYPE (t) = tt;
3080
3081   side_effects = TREE_SIDE_EFFECTS (t);
3082
3083   PROCESS_ARG(0);
3084   PROCESS_ARG(1);
3085   PROCESS_ARG(2);
3086   PROCESS_ARG(3);
3087   PROCESS_ARG(4);
3088
3089   TREE_SIDE_EFFECTS (t) = side_effects;
3090   TREE_THIS_VOLATILE (t)
3091     = (TREE_CODE_CLASS (code) == tcc_reference
3092        && arg0 && TREE_THIS_VOLATILE (arg0));
3093
3094   return t;
3095 }
3096
3097 tree
3098 build7_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3099              tree arg2, tree arg3, tree arg4, tree arg5,
3100              tree arg6 MEM_STAT_DECL)
3101 {
3102   bool constant, read_only, side_effects, invariant;
3103   tree t;
3104
3105   gcc_assert (code == TARGET_MEM_REF);
3106
3107   t = make_node_stat (code PASS_MEM_STAT);
3108   TREE_TYPE (t) = tt;
3109
3110   side_effects = TREE_SIDE_EFFECTS (t);
3111
3112   PROCESS_ARG(0);
3113   PROCESS_ARG(1);
3114   PROCESS_ARG(2);
3115   PROCESS_ARG(3);
3116   PROCESS_ARG(4);
3117   PROCESS_ARG(5);
3118   PROCESS_ARG(6);
3119
3120   TREE_SIDE_EFFECTS (t) = side_effects;
3121   TREE_THIS_VOLATILE (t) = 0;
3122
3123   return t;
3124 }
3125
3126 /* Similar except don't specify the TREE_TYPE
3127    and leave the TREE_SIDE_EFFECTS as 0.
3128    It is permissible for arguments to be null,
3129    or even garbage if their values do not matter.  */
3130
3131 tree
3132 build_nt (enum tree_code code, ...)
3133 {
3134   tree t;
3135   int length;
3136   int i;
3137   va_list p;
3138
3139   va_start (p, code);
3140
3141   t = make_node (code);
3142   length = TREE_CODE_LENGTH (code);
3143
3144   for (i = 0; i < length; i++)
3145     TREE_OPERAND (t, i) = va_arg (p, tree);
3146
3147   va_end (p);
3148   return t;
3149 }
3150 \f
3151 /* Create a DECL_... node of code CODE, name NAME and data type TYPE.
3152    We do NOT enter this node in any sort of symbol table.
3153
3154    layout_decl is used to set up the decl's storage layout.
3155    Other slots are initialized to 0 or null pointers.  */
3156
3157 tree
3158 build_decl_stat (enum tree_code code, tree name, tree type MEM_STAT_DECL)
3159 {
3160   tree t;
3161
3162   t = make_node_stat (code PASS_MEM_STAT);
3163
3164 /*  if (type == error_mark_node)
3165     type = integer_type_node; */
3166 /* That is not done, deliberately, so that having error_mark_node
3167    as the type can suppress useless errors in the use of this variable.  */
3168
3169   DECL_NAME (t) = name;
3170   TREE_TYPE (t) = type;
3171
3172   if (code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL)
3173     layout_decl (t, 0);
3174   else if (code == FUNCTION_DECL)
3175     DECL_MODE (t) = FUNCTION_MODE;
3176
3177   return t;
3178 }
3179
3180 /* Builds and returns function declaration with NAME and TYPE.  */
3181
3182 tree
3183 build_fn_decl (const char *name, tree type)
3184 {
3185   tree id = get_identifier (name);
3186   tree decl = build_decl (FUNCTION_DECL, id, type);
3187
3188   DECL_EXTERNAL (decl) = 1;
3189   TREE_PUBLIC (decl) = 1;
3190   DECL_ARTIFICIAL (decl) = 1;
3191   TREE_NOTHROW (decl) = 1;
3192
3193   return decl;
3194 }
3195
3196 \f
3197 /* BLOCK nodes are used to represent the structure of binding contours
3198    and declarations, once those contours have been exited and their contents
3199    compiled.  This information is used for outputting debugging info.  */
3200
3201 tree
3202 build_block (tree vars, tree subblocks, tree supercontext, tree chain)
3203 {
3204   tree block = make_node (BLOCK);
3205
3206   BLOCK_VARS (block) = vars;
3207   BLOCK_SUBBLOCKS (block) = subblocks;
3208   BLOCK_SUPERCONTEXT (block) = supercontext;
3209   BLOCK_CHAIN (block) = chain;
3210   return block;
3211 }
3212
3213 #if 1 /* ! defined(USE_MAPPED_LOCATION) */
3214 /* ??? gengtype doesn't handle conditionals */
3215 static GTY(()) source_locus last_annotated_node;
3216 #endif
3217
3218 #ifdef USE_MAPPED_LOCATION
3219
3220 expanded_location
3221 expand_location (source_location loc)
3222 {
3223   expanded_location xloc;
3224   if (loc == 0) { xloc.file = NULL; xloc.line = 0;  xloc.column = 0; }
3225   else
3226     {
3227       const struct line_map *map = linemap_lookup (&line_table, loc);
3228       xloc.file = map->to_file;
3229       xloc.line = SOURCE_LINE (map, loc);
3230       xloc.column = SOURCE_COLUMN (map, loc);
3231     };
3232   return xloc;
3233 }
3234
3235 #else
3236
3237 /* Record the exact location where an expression or an identifier were
3238    encountered.  */
3239
3240 void
3241 annotate_with_file_line (tree node, const char *file, int line)
3242 {
3243   /* Roughly one percent of the calls to this function are to annotate
3244      a node with the same information already attached to that node!
3245      Just return instead of wasting memory.  */
3246   if (EXPR_LOCUS (node)
3247       && EXPR_LINENO (node) == line
3248       && (EXPR_FILENAME (node) == file
3249           || !strcmp (EXPR_FILENAME (node), file)))
3250     {
3251       last_annotated_node = EXPR_LOCUS (node);
3252       return;
3253     }
3254
3255   /* In heavily macroized code (such as GCC itself) this single
3256      entry cache can reduce the number of allocations by more
3257      than half.  */
3258   if (last_annotated_node
3259       && last_annotated_node->line == line
3260       && (last_annotated_node->file == file
3261           || !strcmp (last_annotated_node->file, file)))
3262     {
3263       SET_EXPR_LOCUS (node, last_annotated_node);
3264       return;
3265     }
3266
3267   SET_EXPR_LOCUS (node, ggc_alloc (sizeof (location_t)));
3268   EXPR_LINENO (node) = line;
3269   EXPR_FILENAME (node) = file;
3270   last_annotated_node = EXPR_LOCUS (node);
3271 }
3272
3273 void
3274 annotate_with_locus (tree node, location_t locus)
3275 {
3276   annotate_with_file_line (node, locus.file, locus.line);
3277 }
3278 #endif
3279 \f
3280 /* Return a declaration like DDECL except that its DECL_ATTRIBUTES
3281    is ATTRIBUTE.  */
3282
3283 tree
3284 build_decl_attribute_variant (tree ddecl, tree attribute)
3285 {
3286   DECL_ATTRIBUTES (ddecl) = attribute;
3287   return ddecl;
3288 }
3289
3290 /* Borrowed from hashtab.c iterative_hash implementation.  */
3291 #define mix(a,b,c) \
3292 { \
3293   a -= b; a -= c; a ^= (c>>13); \
3294   b -= c; b -= a; b ^= (a<< 8); \
3295   c -= a; c -= b; c ^= ((b&0xffffffff)>>13); \
3296   a -= b; a -= c; a ^= ((c&0xffffffff)>>12); \
3297   b -= c; b -= a; b = (b ^ (a<<16)) & 0xffffffff; \
3298   c -= a; c -= b; c = (c ^ (b>> 5)) & 0xffffffff; \
3299   a -= b; a -= c; a = (a ^ (c>> 3)) & 0xffffffff; \
3300   b -= c; b -= a; b = (b ^ (a<<10)) & 0xffffffff; \
3301   c -= a; c -= b; c = (c ^ (b>>15)) & 0xffffffff; \
3302 }
3303
3304
3305 /* Produce good hash value combining VAL and VAL2.  */
3306 static inline hashval_t
3307 iterative_hash_hashval_t (hashval_t val, hashval_t val2)
3308 {
3309   /* the golden ratio; an arbitrary value.  */
3310   hashval_t a = 0x9e3779b9;
3311
3312   mix (a, val, val2);
3313   return val2;
3314 }
3315
3316 /* Produce good hash value combining PTR and VAL2.  */
3317 static inline hashval_t
3318 iterative_hash_pointer (void *ptr, hashval_t val2)
3319 {
3320   if (sizeof (ptr) == sizeof (hashval_t))
3321     return iterative_hash_hashval_t ((size_t) ptr, val2);
3322   else
3323     {
3324       hashval_t a = (hashval_t) (size_t) ptr;
3325       /* Avoid warnings about shifting of more than the width of the type on
3326          hosts that won't execute this path.  */
3327       int zero = 0;
3328       hashval_t b = (hashval_t) ((size_t) ptr >> (sizeof (hashval_t) * 8 + zero));
3329       mix (a, b, val2);
3330       return val2;
3331     }
3332 }
3333
3334 /* Produce good hash value combining VAL and VAL2.  */
3335 static inline hashval_t
3336 iterative_hash_host_wide_int (HOST_WIDE_INT val, hashval_t val2)
3337 {
3338   if (sizeof (HOST_WIDE_INT) == sizeof (hashval_t))
3339     return iterative_hash_hashval_t (val, val2);
3340   else
3341     {
3342       hashval_t a = (hashval_t) val;
3343       /* Avoid warnings about shifting of more than the width of the type on
3344          hosts that won't execute this path.  */
3345       int zero = 0;
3346       hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 8 + zero));
3347       mix (a, b, val2);
3348       if (sizeof (HOST_WIDE_INT) > 2 * sizeof (hashval_t))
3349         {
3350           hashval_t a = (hashval_t) (val >> (sizeof (hashval_t) * 16 + zero));
3351           hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 24 + zero));
3352           mix (a, b, val2);
3353         }
3354       return val2;
3355     }
3356 }
3357
3358 /* Return a type like TTYPE except that its TYPE_ATTRIBUTE
3359    is ATTRIBUTE.
3360
3361    Record such modified types already made so we don't make duplicates.  */
3362
3363 tree
3364 build_type_attribute_variant (tree ttype, tree attribute)
3365 {
3366   if (! attribute_list_equal (TYPE_ATTRIBUTES (ttype), attribute))
3367     {
3368       hashval_t hashcode = 0;
3369       tree ntype;
3370       enum tree_code code = TREE_CODE (ttype);
3371
3372       ntype = copy_node (ttype);
3373
3374       TYPE_POINTER_TO (ntype) = 0;
3375       TYPE_REFERENCE_TO (ntype) = 0;
3376       TYPE_ATTRIBUTES (ntype) = attribute;
3377
3378       /* Create a new main variant of TYPE.  */
3379       TYPE_MAIN_VARIANT (ntype) = ntype;
3380       TYPE_NEXT_VARIANT (ntype) = 0;
3381       set_type_quals (ntype, TYPE_UNQUALIFIED);
3382
3383       hashcode = iterative_hash_object (code, hashcode);
3384       if (TREE_TYPE (ntype))
3385         hashcode = iterative_hash_object (TYPE_HASH (TREE_TYPE (ntype)),
3386                                           hashcode);
3387       hashcode = attribute_hash_list (attribute, hashcode);
3388
3389       switch (TREE_CODE (ntype))
3390         {
3391         case FUNCTION_TYPE:
3392           hashcode = type_hash_list (TYPE_ARG_TYPES (ntype), hashcode);
3393           break;
3394         case ARRAY_TYPE:
3395           hashcode = iterative_hash_object (TYPE_HASH (TYPE_DOMAIN (ntype)),
3396                                             hashcode);
3397           break;
3398         case INTEGER_TYPE:
3399           hashcode = iterative_hash_object
3400             (TREE_INT_CST_LOW (TYPE_MAX_VALUE (ntype)), hashcode);
3401           hashcode = iterative_hash_object
3402             (TREE_INT_CST_HIGH (TYPE_MAX_VALUE (ntype)), hashcode);
3403           break;
3404         case REAL_TYPE:
3405           {
3406             unsigned int precision = TYPE_PRECISION (ntype);
3407             hashcode = iterative_hash_object (precision, hashcode);
3408           }
3409           break;
3410         default:
3411           break;
3412         }
3413
3414       ntype = type_hash_canon (hashcode, ntype);
3415       ttype = build_qualified_type (ntype, TYPE_QUALS (ttype));
3416     }
3417
3418   return ttype;
3419 }
3420
3421
3422 /* Return nonzero if IDENT is a valid name for attribute ATTR,
3423    or zero if not.
3424
3425    We try both `text' and `__text__', ATTR may be either one.  */
3426 /* ??? It might be a reasonable simplification to require ATTR to be only
3427    `text'.  One might then also require attribute lists to be stored in
3428    their canonicalized form.  */
3429
3430 static int
3431 is_attribute_with_length_p (const char *attr, int attr_len, tree ident)
3432 {
3433   int ident_len;
3434   const char *p;
3435
3436   if (TREE_CODE (ident) != IDENTIFIER_NODE)
3437     return 0;
3438
3439   p = IDENTIFIER_POINTER (ident);
3440   ident_len = IDENTIFIER_LENGTH (ident);
3441
3442   if (ident_len == attr_len
3443       && strcmp (attr, p) == 0)
3444     return 1;
3445
3446   /* If ATTR is `__text__', IDENT must be `text'; and vice versa.  */
3447   if (attr[0] == '_')
3448     {
3449       gcc_assert (attr[1] == '_');
3450       gcc_assert (attr[attr_len - 2] == '_');
3451       gcc_assert (attr[attr_len - 1] == '_');
3452       gcc_assert (attr[1] == '_');
3453       if (ident_len == attr_len - 4
3454           && strncmp (attr + 2, p, attr_len - 4) == 0)
3455         return 1;
3456     }
3457   else
3458     {
3459       if (ident_len == attr_len + 4
3460           && p[0] == '_' && p[1] == '_'
3461           && p[ident_len - 2] == '_' && p[ident_len - 1] == '_'
3462           && strncmp (attr, p + 2, attr_len) == 0)
3463         return 1;
3464     }
3465
3466   return 0;
3467 }
3468
3469 /* Return nonzero if IDENT is a valid name for attribute ATTR,
3470    or zero if not.
3471
3472    We try both `text' and `__text__', ATTR may be either one.  */
3473
3474 int
3475 is_attribute_p (const char *attr, tree ident)
3476 {
3477   return is_attribute_with_length_p (attr, strlen (attr), ident);
3478 }
3479
3480 /* Given an attribute name and a list of attributes, return a pointer to the
3481    attribute's list element if the attribute is part of the list, or NULL_TREE
3482    if not found.  If the attribute appears more than once, this only
3483    returns the first occurrence; the TREE_CHAIN of the return value should
3484    be passed back in if further occurrences are wanted.  */
3485
3486 tree
3487 lookup_attribute (const char *attr_name, tree list)
3488 {
3489   tree l;
3490   size_t attr_len = strlen (attr_name);
3491
3492   for (l = list; l; l = TREE_CHAIN (l))
3493     {
3494       gcc_assert (TREE_CODE (TREE_PURPOSE (l)) == IDENTIFIER_NODE);
3495       if (is_attribute_with_length_p (attr_name, attr_len, TREE_PURPOSE (l)))
3496         return l;
3497     }
3498
3499   return NULL_TREE;
3500 }
3501
3502 /* Remove any instances of attribute ATTR_NAME in LIST and return the
3503    modified list.  */
3504
3505 tree
3506 remove_attribute (const char *attr_name, tree list)
3507 {
3508   tree *p;
3509   size_t attr_len = strlen (attr_name);
3510
3511   for (p = &list; *p; )
3512     {
3513       tree l = *p;
3514       gcc_assert (TREE_CODE (TREE_PURPOSE (l)) == IDENTIFIER_NODE);
3515       if (is_attribute_with_length_p (attr_name, attr_len, TREE_PURPOSE (l)))
3516         *p = TREE_CHAIN (l);
3517       else
3518         p = &TREE_CHAIN (l);
3519     }
3520
3521   return list;
3522 }
3523
3524 /* Return an attribute list that is the union of a1 and a2.  */
3525
3526 tree
3527 merge_attributes (tree a1, tree a2)
3528 {
3529   tree attributes;
3530
3531   /* Either one unset?  Take the set one.  */
3532
3533   if ((attributes = a1) == 0)
3534     attributes = a2;
3535
3536   /* One that completely contains the other?  Take it.  */
3537
3538   else if (a2 != 0 && ! attribute_list_contained (a1, a2))
3539     {
3540       if (attribute_list_contained (a2, a1))
3541         attributes = a2;
3542       else
3543         {
3544           /* Pick the longest list, and hang on the other list.  */
3545
3546           if (list_length (a1) < list_length (a2))
3547             attributes = a2, a2 = a1;
3548
3549           for (; a2 != 0; a2 = TREE_CHAIN (a2))
3550             {
3551               tree a;
3552               for (a = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
3553                                          attributes);
3554                    a != NULL_TREE;
3555                    a = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
3556                                          TREE_CHAIN (a)))
3557                 {
3558                   if (simple_cst_equal (TREE_VALUE (a), TREE_VALUE (a2)) == 1)
3559                     break;
3560                 }
3561               if (a == NULL_TREE)
3562                 {
3563                   a1 = copy_node (a2);
3564                   TREE_CHAIN (a1) = attributes;
3565                   attributes = a1;
3566                 }
3567             }
3568         }
3569     }
3570   return attributes;
3571 }
3572
3573 /* Given types T1 and T2, merge their attributes and return
3574   the result.  */
3575
3576 tree
3577 merge_type_attributes (tree t1, tree t2)
3578 {
3579   return merge_attributes (TYPE_ATTRIBUTES (t1),
3580                            TYPE_ATTRIBUTES (t2));
3581 }
3582
3583 /* Given decls OLDDECL and NEWDECL, merge their attributes and return
3584    the result.  */
3585
3586 tree
3587 merge_decl_attributes (tree olddecl, tree newdecl)
3588 {
3589   return merge_attributes (DECL_ATTRIBUTES (olddecl),
3590                            DECL_ATTRIBUTES (newdecl));
3591 }
3592
3593 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
3594
3595 /* Specialization of merge_decl_attributes for various Windows targets.
3596
3597    This handles the following situation:
3598
3599      __declspec (dllimport) int foo;
3600      int foo;
3601
3602    The second instance of `foo' nullifies the dllimport.  */
3603
3604 tree
3605 merge_dllimport_decl_attributes (tree old, tree new)
3606 {
3607   tree a;
3608   int delete_dllimport_p = 1;
3609
3610   /* What we need to do here is remove from `old' dllimport if it doesn't
3611      appear in `new'.  dllimport behaves like extern: if a declaration is
3612      marked dllimport and a definition appears later, then the object
3613      is not dllimport'd.  We also remove a `new' dllimport if the old list
3614      contains dllexport:  dllexport always overrides dllimport, regardless
3615      of the order of declaration.  */
3616   if (!VAR_OR_FUNCTION_DECL_P (new))
3617     delete_dllimport_p = 0;
3618   else if (DECL_DLLIMPORT_P (new)
3619            && lookup_attribute ("dllexport", DECL_ATTRIBUTES (old)))
3620     {
3621       DECL_DLLIMPORT_P (new) = 0;
3622       warning (OPT_Wattributes, "%q+D already declared with dllexport attribute: "
3623               "dllimport ignored", new);
3624     }
3625   else if (DECL_DLLIMPORT_P (old) && !DECL_DLLIMPORT_P (new))
3626     {
3627       /* Warn about overriding a symbol that has already been used. eg:
3628            extern int __attribute__ ((dllimport)) foo;
3629            int* bar () {return &foo;}
3630            int foo;
3631       */
3632       if (TREE_USED (old))
3633         {
3634           warning (0, "%q+D redeclared without dllimport attribute "
3635                    "after being referenced with dll linkage", new);
3636           /* If we have used a variable's address with dllimport linkage,
3637               keep the old DECL_DLLIMPORT_P flag: the ADDR_EXPR using the
3638               decl may already have had TREE_INVARIANT and TREE_CONSTANT
3639               computed.
3640               We still remove the attribute so that assembler code refers
3641               to '&foo rather than '_imp__foo'.  */
3642           if (TREE_CODE (old) == VAR_DECL && TREE_ADDRESSABLE (old))
3643             DECL_DLLIMPORT_P (new) = 1;
3644         }
3645
3646       /* Let an inline definition silently override the external reference,
3647          but otherwise warn about attribute inconsistency.  */
3648       else if (TREE_CODE (new) == VAR_DECL
3649                || !DECL_DECLARED_INLINE_P (new))
3650         warning (OPT_Wattributes, "%q+D redeclared without dllimport attribute: "
3651                   "previous dllimport ignored", new);
3652     }
3653   else
3654     delete_dllimport_p = 0;
3655
3656   a = merge_attributes (DECL_ATTRIBUTES (old), DECL_ATTRIBUTES (new));
3657
3658   if (delete_dllimport_p)
3659     {
3660       tree prev, t;
3661       const size_t attr_len = strlen ("dllimport");
3662
3663       /* Scan the list for dllimport and delete it.  */
3664       for (prev = NULL_TREE, t = a; t; prev = t, t = TREE_CHAIN (t))
3665         {
3666           if (is_attribute_with_length_p ("dllimport", attr_len,
3667                                           TREE_PURPOSE (t)))
3668             {
3669               if (prev == NULL_TREE)
3670                 a = TREE_CHAIN (a);
3671               else
3672                 TREE_CHAIN (prev) = TREE_CHAIN (t);
3673               break;
3674             }
3675         }
3676     }
3677
3678   return a;
3679 }
3680
3681 /* Handle a "dllimport" or "dllexport" attribute; arguments as in
3682    struct attribute_spec.handler.  */
3683
3684 tree
3685 handle_dll_attribute (tree * pnode, tree name, tree args, int flags,
3686                       bool *no_add_attrs)
3687 {
3688   tree node = *pnode;
3689
3690   /* These attributes may apply to structure and union types being created,
3691      but otherwise should pass to the declaration involved.  */
3692   if (!DECL_P (node))
3693     {
3694       if (flags & ((int) ATTR_FLAG_DECL_NEXT | (int) ATTR_FLAG_FUNCTION_NEXT
3695                    | (int) ATTR_FLAG_ARRAY_NEXT))
3696         {
3697           *no_add_attrs = true;
3698           return tree_cons (name, args, NULL_TREE);
3699         }
3700       if (TREE_CODE (node) != RECORD_TYPE && TREE_CODE (node) != UNION_TYPE)
3701         {
3702           warning (OPT_Wattributes, "%qs attribute ignored",
3703                    IDENTIFIER_POINTER (name));
3704           *no_add_attrs = true;
3705         }
3706
3707       return NULL_TREE;
3708     }
3709
3710   /* Report error on dllimport ambiguities seen now before they cause
3711      any damage.  */
3712   if (is_attribute_p ("dllimport", name))
3713     {
3714       /* Honor any target-specific overrides. */
3715       if (!targetm.valid_dllimport_attribute_p (node))
3716         *no_add_attrs = true;
3717
3718      else if (TREE_CODE (node) == FUNCTION_DECL
3719                 && DECL_DECLARED_INLINE_P (node))
3720         {
3721           warning (OPT_Wattributes, "inline function %q+D declared as "
3722                   " dllimport: attribute ignored", node);
3723           *no_add_attrs = true;
3724         }
3725       /* Like MS, treat definition of dllimported variables and
3726          non-inlined functions on declaration as syntax errors. */
3727      else if (TREE_CODE (node) == FUNCTION_DECL && DECL_INITIAL (node))
3728         {
3729           error ("function %q+D definition is marked dllimport", node);
3730           *no_add_attrs = true;
3731         }
3732
3733      else if (TREE_CODE (node) == VAR_DECL)
3734         {
3735           if (DECL_INITIAL (node))
3736             {
3737               error ("variable %q+D definition is marked dllimport",
3738                      node);
3739               *no_add_attrs = true;
3740             }
3741
3742           /* `extern' needn't be specified with dllimport.
3743              Specify `extern' now and hope for the best.  Sigh.  */
3744           DECL_EXTERNAL (node) = 1;
3745           /* Also, implicitly give dllimport'd variables declared within
3746              a function global scope, unless declared static.  */
3747           if (current_function_decl != NULL_TREE && !TREE_STATIC (node))
3748             TREE_PUBLIC (node) = 1;
3749         }
3750
3751       if (*no_add_attrs == false)
3752         DECL_DLLIMPORT_P (node) = 1;
3753     }
3754
3755   /*  Report error if symbol is not accessible at global scope.  */
3756   if (!TREE_PUBLIC (node)
3757       && (TREE_CODE (node) == VAR_DECL
3758           || TREE_CODE (node) == FUNCTION_DECL))
3759     {
3760       error ("external linkage required for symbol %q+D because of "
3761              "%qs attribute", node, IDENTIFIER_POINTER (name));
3762       *no_add_attrs = true;
3763     }
3764
3765   return NULL_TREE;
3766 }
3767
3768 #endif /* TARGET_DLLIMPORT_DECL_ATTRIBUTES  */
3769 \f
3770 /* Set the type qualifiers for TYPE to TYPE_QUALS, which is a bitmask
3771    of the various TYPE_QUAL values.  */
3772
3773 static void
3774 set_type_quals (tree type, int type_quals)
3775 {
3776   TYPE_READONLY (type) = (type_quals & TYPE_QUAL_CONST) != 0;
3777   TYPE_VOLATILE (type) = (type_quals & TYPE_QUAL_VOLATILE) != 0;
3778   TYPE_RESTRICT (type) = (type_quals & TYPE_QUAL_RESTRICT) != 0;
3779 }
3780
3781 /* Returns true iff cand is equivalent to base with type_quals.  */
3782
3783 bool
3784 check_qualified_type (tree cand, tree base, int type_quals)
3785 {
3786   return (TYPE_QUALS (cand) == type_quals
3787           && TYPE_NAME (cand) == TYPE_NAME (base)
3788           /* Apparently this is needed for Objective-C.  */
3789           && TYPE_CONTEXT (cand) == TYPE_CONTEXT (base)
3790           && attribute_list_equal (TYPE_ATTRIBUTES (cand),
3791                                    TYPE_ATTRIBUTES (base)));
3792 }
3793
3794 /* Return a version of the TYPE, qualified as indicated by the
3795    TYPE_QUALS, if one exists.  If no qualified version exists yet,
3796    return NULL_TREE.  */
3797
3798 tree
3799 get_qualified_type (tree type, int type_quals)
3800 {
3801   tree t;
3802
3803   if (TYPE_QUALS (type) == type_quals)
3804     return type;
3805
3806   /* Search the chain of variants to see if there is already one there just
3807      like the one we need to have.  If so, use that existing one.  We must
3808      preserve the TYPE_NAME, since there is code that depends on this.  */
3809   for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
3810     if (check_qualified_type (t, type, type_quals))
3811       return t;
3812
3813   return NULL_TREE;
3814 }
3815
3816 /* Like get_qualified_type, but creates the type if it does not
3817    exist.  This function never returns NULL_TREE.  */
3818
3819 tree
3820 build_qualified_type (tree type, int type_quals)
3821 {
3822   tree t;
3823
3824   /* See if we already have the appropriate qualified variant.  */
3825   t = get_qualified_type (type, type_quals);
3826
3827   /* If not, build it.  */
3828   if (!t)
3829     {
3830       t = build_variant_type_copy (type);
3831       set_type_quals (t, type_quals);
3832     }
3833
3834   return t;
3835 }
3836
3837 /* Create a new distinct copy of TYPE.  The new type is made its own
3838    MAIN_VARIANT.  */
3839
3840 tree
3841 build_distinct_type_copy (tree type)
3842 {
3843   tree t = copy_node (type);
3844
3845   TYPE_POINTER_TO (t) = 0;
3846   TYPE_REFERENCE_TO (t) = 0;
3847
3848   /* Make it its own variant.  */
3849   TYPE_MAIN_VARIANT (t) = t;
3850   TYPE_NEXT_VARIANT (t) = 0;
3851
3852   return t;
3853 }
3854
3855 /* Create a new variant of TYPE, equivalent but distinct.
3856    This is so the caller can modify it.  */
3857
3858 tree
3859 build_variant_type_copy (tree type)
3860 {
3861   tree t, m = TYPE_MAIN_VARIANT (type);
3862
3863   t = build_distinct_type_copy (type);
3864
3865   /* Add the new type to the chain of variants of TYPE.  */
3866   TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (m);
3867   TYPE_NEXT_VARIANT (m) = t;
3868   TYPE_MAIN_VARIANT (t) = m;
3869
3870   return t;
3871 }
3872 \f
3873 /* Return true if the from tree in both tree maps are equal.  */
3874
3875 int
3876 tree_map_eq (const void *va, const void *vb)
3877 {
3878   const struct tree_map  *a = va, *b = vb;
3879   return (a->from == b->from);
3880 }
3881
3882 /* Hash a from tree in a tree_map.  */
3883
3884 unsigned int
3885 tree_map_hash (const void *item)
3886 {
3887   return (((const struct tree_map *) item)->hash);
3888 }
3889
3890 /* Return true if this tree map structure is marked for garbage collection
3891    purposes.  We simply return true if the from tree is marked, so that this
3892    structure goes away when the from tree goes away.  */
3893
3894 int
3895 tree_map_marked_p (const void *p)
3896 {
3897   tree from = ((struct tree_map *) p)->from;
3898
3899   return ggc_marked_p (from);
3900 }
3901
3902 /* Return true if the trees in the tree_int_map *'s VA and VB are equal.  */
3903
3904 static int
3905 tree_int_map_eq (const void *va, const void *vb)
3906 {
3907   const struct tree_int_map  *a = va, *b = vb;
3908   return (a->from == b->from);
3909 }
3910
3911 /* Hash a from tree in the tree_int_map * ITEM.  */
3912
3913 static unsigned int
3914 tree_int_map_hash (const void *item)
3915 {
3916   return htab_hash_pointer (((const struct tree_int_map *)item)->from);
3917 }
3918
3919 /* Return true if this tree int map structure is marked for garbage collection
3920    purposes.  We simply return true if the from tree_int_map *P's from tree is marked, so that this
3921    structure goes away when the from tree goes away.  */
3922
3923 static int
3924 tree_int_map_marked_p (const void *p)
3925 {
3926   tree from = ((struct tree_int_map *) p)->from;
3927
3928   return ggc_marked_p (from);
3929 }
3930 /* Lookup an init priority for FROM, and return it if we find one.  */
3931
3932 unsigned short
3933 decl_init_priority_lookup (tree from)
3934 {
3935   struct tree_int_map *h, in;
3936   in.from = from;
3937
3938   h = htab_find_with_hash (init_priority_for_decl,
3939                            &in, htab_hash_pointer (from));
3940   if (h)
3941     return h->to;
3942   return 0;
3943 }
3944
3945 /* Insert a mapping FROM->TO in the init priority hashtable.  */
3946
3947 void
3948 decl_init_priority_insert (tree from, unsigned short to)
3949 {
3950   struct tree_int_map *h;
3951   void **loc;
3952
3953   h = ggc_alloc (sizeof (struct tree_int_map));
3954   h->from = from;
3955   h->to = to;
3956   loc = htab_find_slot_with_hash (init_priority_for_decl, h,
3957                                   htab_hash_pointer (from), INSERT);
3958   *(struct tree_int_map **) loc = h;
3959 }
3960
3961 /* Look up a restrict qualified base decl for FROM.  */
3962
3963 tree
3964 decl_restrict_base_lookup (tree from)
3965 {
3966   struct tree_map *h;
3967   struct tree_map in;
3968
3969   in.from = from;
3970   h = htab_find_with_hash (restrict_base_for_decl, &in,
3971                            htab_hash_pointer (from));
3972   return h ? h->to : NULL_TREE;
3973 }
3974
3975 /* Record the restrict qualified base TO for FROM.  */
3976
3977 void
3978 decl_restrict_base_insert (tree from, tree to)
3979 {
3980   struct tree_map *h;
3981   void **loc;
3982
3983   h = ggc_alloc (sizeof (struct tree_map));
3984   h->hash = htab_hash_pointer (from);
3985   h->from = from;
3986   h->to = to;
3987   loc = htab_find_slot_with_hash (restrict_base_for_decl, h, h->hash, INSERT);
3988   *(struct tree_map **) loc = h;
3989 }
3990
3991 /* Print out the statistics for the DECL_DEBUG_EXPR hash table.  */
3992
3993 static void
3994 print_debug_expr_statistics (void)
3995 {
3996   fprintf (stderr, "DECL_DEBUG_EXPR  hash: size %ld, %ld elements, %f collisions\n",
3997            (long) htab_size (debug_expr_for_decl),
3998            (long) htab_elements (debug_expr_for_decl),
3999            htab_collisions (debug_expr_for_decl));
4000 }
4001
4002 /* Print out the statistics for the DECL_VALUE_EXPR hash table.  */
4003
4004 static void
4005 print_value_expr_statistics (void)
4006 {
4007   fprintf (stderr, "DECL_VALUE_EXPR  hash: size %ld, %ld elements, %f collisions\n",
4008            (long) htab_size (value_expr_for_decl),
4009            (long) htab_elements (value_expr_for_decl),
4010            htab_collisions (value_expr_for_decl));
4011 }
4012
4013 /* Print out statistics for the RESTRICT_BASE_FOR_DECL hash table, but
4014    don't print anything if the table is empty.  */
4015
4016 static void
4017 print_restrict_base_statistics (void)
4018 {
4019   if (htab_elements (restrict_base_for_decl) != 0)
4020     fprintf (stderr,
4021              "RESTRICT_BASE    hash: size %ld, %ld elements, %f collisions\n",
4022              (long) htab_size (restrict_base_for_decl),
4023              (long) htab_elements (restrict_base_for_decl),
4024              htab_collisions (restrict_base_for_decl));
4025 }
4026
4027 /* Lookup a debug expression for FROM, and return it if we find one.  */
4028
4029 tree
4030 decl_debug_expr_lookup (tree from)
4031 {
4032   struct tree_map *h, in;
4033   in.from = from;
4034
4035   h = htab_find_with_hash (debug_expr_for_decl, &in, htab_hash_pointer (from));
4036   if (h)
4037     return h->to;
4038   return NULL_TREE;
4039 }
4040
4041 /* Insert a mapping FROM->TO in the debug expression hashtable.  */
4042
4043 void
4044 decl_debug_expr_insert (tree from, tree to)
4045 {
4046   struct tree_map *h;
4047   void **loc;
4048
4049   h = ggc_alloc (sizeof (struct tree_map));
4050   h->hash = htab_hash_pointer (from);
4051   h->from = from;
4052   h->to = to;
4053   loc = htab_find_slot_with_hash (debug_expr_for_decl, h, h->hash, INSERT);
4054   *(struct tree_map **) loc = h;
4055 }
4056
4057 /* Lookup a value expression for FROM, and return it if we find one.  */
4058
4059 tree
4060 decl_value_expr_lookup (tree from)
4061 {
4062   struct tree_map *h, in;
4063   in.from = from;
4064
4065   h = htab_find_with_hash (value_expr_for_decl, &in, htab_hash_pointer (from));
4066   if (h)
4067     return h->to;
4068   return NULL_TREE;
4069 }
4070
4071 /* Insert a mapping FROM->TO in the value expression hashtable.  */
4072
4073 void
4074 decl_value_expr_insert (tree from, tree to)
4075 {
4076   struct tree_map *h;
4077   void **loc;
4078
4079   h = ggc_alloc (sizeof (struct tree_map));
4080   h->hash = htab_hash_pointer (from);
4081   h->from = from;
4082   h->to = to;
4083   loc = htab_find_slot_with_hash (value_expr_for_decl, h, h->hash, INSERT);
4084   *(struct tree_map **) loc = h;
4085 }
4086
4087 /* Hashing of types so that we don't make duplicates.
4088    The entry point is `type_hash_canon'.  */
4089
4090 /* Compute a hash code for a list of types (chain of TREE_LIST nodes
4091    with types in the TREE_VALUE slots), by adding the hash codes
4092    of the individual types.  */
4093
4094 unsigned int
4095 type_hash_list (tree list, hashval_t hashcode)
4096 {
4097   tree tail;
4098
4099   for (tail = list; tail; tail = TREE_CHAIN (tail))
4100     if (TREE_VALUE (tail) != error_mark_node)
4101       hashcode = iterative_hash_object (TYPE_HASH (TREE_VALUE (tail)),
4102                                         hashcode);
4103
4104   return hashcode;
4105 }
4106
4107 /* These are the Hashtable callback functions.  */
4108
4109 /* Returns true iff the types are equivalent.  */
4110
4111 static int
4112 type_hash_eq (const void *va, const void *vb)
4113 {
4114   const struct type_hash *a = va, *b = vb;
4115
4116   /* First test the things that are the same for all types.  */
4117   if (a->hash != b->hash
4118       || TREE_CODE (a->type) != TREE_CODE (b->type)
4119       || TREE_TYPE (a->type) != TREE_TYPE (b->type)
4120       || !attribute_list_equal (TYPE_ATTRIBUTES (a->type),
4121                                  TYPE_ATTRIBUTES (b->type))
4122       || TYPE_ALIGN (a->type) != TYPE_ALIGN (b->type)
4123       || TYPE_MODE (a->type) != TYPE_MODE (b->type))
4124     return 0;
4125
4126   switch (TREE_CODE (a->type))
4127     {
4128     case VOID_TYPE:
4129     case COMPLEX_TYPE:
4130     case POINTER_TYPE:
4131     case REFERENCE_TYPE:
4132       return 1;
4133
4134     case VECTOR_TYPE:
4135       return TYPE_VECTOR_SUBPARTS (a->type) == TYPE_VECTOR_SUBPARTS (b->type);
4136
4137     case ENUMERAL_TYPE:
4138       if (TYPE_VALUES (a->type) != TYPE_VALUES (b->type)
4139           && !(TYPE_VALUES (a->type)
4140                && TREE_CODE (TYPE_VALUES (a->type)) == TREE_LIST
4141                && TYPE_VALUES (b->type)
4142                && TREE_CODE (TYPE_VALUES (b->type)) == TREE_LIST
4143                && type_list_equal (TYPE_VALUES (a->type),
4144                                    TYPE_VALUES (b->type))))
4145         return 0;
4146
4147       /* ... fall through ... */
4148
4149     case INTEGER_TYPE:
4150     case REAL_TYPE:
4151     case BOOLEAN_TYPE:
4152       return ((TYPE_MAX_VALUE (a->type) == TYPE_MAX_VALUE (b->type)
4153                || tree_int_cst_equal (TYPE_MAX_VALUE (a->type),
4154                                       TYPE_MAX_VALUE (b->type)))
4155               && (TYPE_MIN_VALUE (a->type) == TYPE_MIN_VALUE (b->type)
4156                   || tree_int_cst_equal (TYPE_MIN_VALUE (a->type),
4157                                          TYPE_MIN_VALUE (b->type))));
4158
4159     case OFFSET_TYPE:
4160       return TYPE_OFFSET_BASETYPE (a->type) == TYPE_OFFSET_BASETYPE (b->type);
4161
4162     case METHOD_TYPE:
4163       return (TYPE_METHOD_BASETYPE (a->type) == TYPE_METHOD_BASETYPE (b->type)
4164               && (TYPE_ARG_TYPES (a->type) == TYPE_ARG_TYPES (b->type)
4165                   || (TYPE_ARG_TYPES (a->type)
4166                       && TREE_CODE (TYPE_ARG_TYPES (a->type)) == TREE_LIST
4167                       && TYPE_ARG_TYPES (b->type)
4168                       && TREE_CODE (TYPE_ARG_TYPES (b->type)) == TREE_LIST
4169                       && type_list_equal (TYPE_ARG_TYPES (a->type),
4170                                           TYPE_ARG_TYPES (b->type)))));
4171
4172     case ARRAY_TYPE:
4173       return TYPE_DOMAIN (a->type) == TYPE_DOMAIN (b->type);
4174
4175     case RECORD_TYPE:
4176     case UNION_TYPE:
4177     case QUAL_UNION_TYPE:
4178       return (TYPE_FIELDS (a->type) == TYPE_FIELDS (b->type)
4179               || (TYPE_FIELDS (a->type)
4180                   && TREE_CODE (TYPE_FIELDS (a->type)) == TREE_LIST
4181                   && TYPE_FIELDS (b->type)
4182                   && TREE_CODE (TYPE_FIELDS (b->type)) == TREE_LIST
4183                   && type_list_equal (TYPE_FIELDS (a->type),
4184                                       TYPE_FIELDS (b->type))));
4185
4186     case FUNCTION_TYPE:
4187       return (TYPE_ARG_TYPES (a->type) == TYPE_ARG_TYPES (b->type)
4188               || (TYPE_ARG_TYPES (a->type)
4189                   && TREE_CODE (TYPE_ARG_TYPES (a->type)) == TREE_LIST
4190                   && TYPE_ARG_TYPES (b->type)
4191                   && TREE_CODE (TYPE_ARG_TYPES (b->type)) == TREE_LIST
4192                   && type_list_equal (TYPE_ARG_TYPES (a->type),
4193                                       TYPE_ARG_TYPES (b->type))));
4194
4195     default:
4196       return 0;
4197     }
4198 }
4199
4200 /* Return the cached hash value.  */
4201
4202 static hashval_t
4203 type_hash_hash (const void *item)
4204 {
4205   return ((const struct type_hash *) item)->hash;
4206 }
4207
4208 /* Look in the type hash table for a type isomorphic to TYPE.
4209    If one is found, return it.  Otherwise return 0.  */
4210
4211 tree
4212 type_hash_lookup (hashval_t hashcode, tree type)
4213 {
4214   struct type_hash *h, in;
4215
4216   /* The TYPE_ALIGN field of a type is set by layout_type(), so we
4217      must call that routine before comparing TYPE_ALIGNs.  */
4218   layout_type (type);
4219
4220   in.hash = hashcode;
4221   in.type = type;
4222
4223   h = htab_find_with_hash (type_hash_table, &in, hashcode);
4224   if (h)
4225     return h->type;
4226   return NULL_TREE;
4227 }
4228
4229 /* Add an entry to the type-hash-table
4230    for a type TYPE whose hash code is HASHCODE.  */
4231
4232 void
4233 type_hash_add (hashval_t hashcode, tree type)
4234 {
4235   struct type_hash *h;
4236   void **loc;
4237
4238   h = ggc_alloc (sizeof (struct type_hash));
4239   h->hash = hashcode;
4240   h->type = type;
4241   loc = htab_find_slot_with_hash (type_hash_table, h, hashcode, INSERT);
4242   *(struct type_hash **) loc = h;
4243 }
4244
4245 /* Given TYPE, and HASHCODE its hash code, return the canonical
4246    object for an identical type if one already exists.
4247    Otherwise, return TYPE, and record it as the canonical object.
4248
4249    To use this function, first create a type of the sort you want.
4250    Then compute its hash code from the fields of the type that
4251    make it different from other similar types.
4252    Then call this function and use the value.  */
4253
4254 tree
4255 type_hash_canon (unsigned int hashcode, tree type)
4256 {
4257   tree t1;
4258
4259   /* The hash table only contains main variants, so ensure that's what we're
4260      being passed.  */
4261   gcc_assert (TYPE_MAIN_VARIANT (type) == type);
4262
4263   if (!lang_hooks.types.hash_types)
4264     return type;
4265
4266   /* See if the type is in the hash table already.  If so, return it.
4267      Otherwise, add the type.  */
4268   t1 = type_hash_lookup (hashcode, type);
4269   if (t1 != 0)
4270     {
4271 #ifdef GATHER_STATISTICS
4272       tree_node_counts[(int) t_kind]--;
4273       tree_node_sizes[(int) t_kind] -= sizeof (struct tree_type);
4274 #endif
4275       return t1;
4276     }
4277   else
4278     {
4279       type_hash_add (hashcode, type);
4280       return type;
4281     }
4282 }
4283
4284 /* See if the data pointed to by the type hash table is marked.  We consider
4285    it marked if the type is marked or if a debug type number or symbol
4286    table entry has been made for the type.  This reduces the amount of
4287    debugging output and eliminates that dependency of the debug output on
4288    the number of garbage collections.  */
4289
4290 static int
4291 type_hash_marked_p (const void *p)
4292 {
4293   tree type = ((struct type_hash *) p)->type;
4294
4295   return ggc_marked_p (type) || TYPE_SYMTAB_POINTER (type);
4296 }
4297
4298 static void
4299 print_type_hash_statistics (void)
4300 {
4301   fprintf (stderr, "Type hash: size %ld, %ld elements, %f collisions\n",
4302            (long) htab_size (type_hash_table),
4303            (long) htab_elements (type_hash_table),
4304            htab_collisions (type_hash_table));
4305 }
4306
4307 /* Compute a hash code for a list of attributes (chain of TREE_LIST nodes
4308    with names in the TREE_PURPOSE slots and args in the TREE_VALUE slots),
4309    by adding the hash codes of the individual attributes.  */
4310
4311 unsigned int
4312 attribute_hash_list (tree list, hashval_t hashcode)
4313 {
4314   tree tail;
4315
4316   for (tail = list; tail; tail = TREE_CHAIN (tail))
4317     /* ??? Do we want to add in TREE_VALUE too? */
4318     hashcode = iterative_hash_object
4319       (IDENTIFIER_HASH_VALUE (TREE_PURPOSE (tail)), hashcode);
4320   return hashcode;
4321 }
4322
4323 /* Given two lists of attributes, return true if list l2 is
4324    equivalent to l1.  */
4325
4326 int
4327 attribute_list_equal (tree l1, tree l2)
4328 {
4329   return attribute_list_contained (l1, l2)
4330          && attribute_list_contained (l2, l1);
4331 }
4332
4333 /* Given two lists of attributes, return true if list L2 is
4334    completely contained within L1.  */
4335 /* ??? This would be faster if attribute names were stored in a canonicalized
4336    form.  Otherwise, if L1 uses `foo' and L2 uses `__foo__', the long method
4337    must be used to show these elements are equivalent (which they are).  */
4338 /* ??? It's not clear that attributes with arguments will always be handled
4339    correctly.  */
4340
4341 int
4342 attribute_list_contained (tree l1, tree l2)
4343 {
4344   tree t1, t2;
4345
4346   /* First check the obvious, maybe the lists are identical.  */
4347   if (l1 == l2)
4348     return 1;
4349
4350   /* Maybe the lists are similar.  */
4351   for (t1 = l1, t2 = l2;
4352        t1 != 0 && t2 != 0
4353         && TREE_PURPOSE (t1) == TREE_PURPOSE (t2)
4354         && TREE_VALUE (t1) == TREE_VALUE (t2);
4355        t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2));
4356
4357   /* Maybe the lists are equal.  */
4358   if (t1 == 0 && t2 == 0)
4359     return 1;
4360
4361   for (; t2 != 0; t2 = TREE_CHAIN (t2))
4362     {
4363       tree attr;
4364       for (attr = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (t2)), l1);
4365            attr != NULL_TREE;
4366            attr = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (t2)),
4367                                     TREE_CHAIN (attr)))
4368         {
4369           if (simple_cst_equal (TREE_VALUE (t2), TREE_VALUE (attr)) == 1)
4370             break;
4371         }
4372
4373       if (attr == 0)
4374         return 0;
4375
4376       if (simple_cst_equal (TREE_VALUE (t2), TREE_VALUE (attr)) != 1)
4377         return 0;
4378     }
4379
4380   return 1;
4381 }
4382
4383 /* Given two lists of types
4384    (chains of TREE_LIST nodes with types in the TREE_VALUE slots)
4385    return 1 if the lists contain the same types in the same order.
4386    Also, the TREE_PURPOSEs must match.  */
4387
4388 int
4389 type_list_equal (tree l1, tree l2)
4390 {
4391   tree t1, t2;
4392
4393   for (t1 = l1, t2 = l2; t1 && t2; t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2))
4394     if (TREE_VALUE (t1) != TREE_VALUE (t2)
4395         || (TREE_PURPOSE (t1) != TREE_PURPOSE (t2)
4396             && ! (1 == simple_cst_equal (TREE_PURPOSE (t1), TREE_PURPOSE (t2))
4397                   && (TREE_TYPE (TREE_PURPOSE (t1))
4398                       == TREE_TYPE (TREE_PURPOSE (t2))))))
4399       return 0;
4400
4401   return t1 == t2;
4402 }
4403
4404 /* Returns the number of arguments to the FUNCTION_TYPE or METHOD_TYPE
4405    given by TYPE.  If the argument list accepts variable arguments,
4406    then this function counts only the ordinary arguments.  */
4407
4408 int
4409 type_num_arguments (tree type)
4410 {
4411   int i = 0;
4412   tree t;
4413
4414   for (t = TYPE_ARG_TYPES (type); t; t = TREE_CHAIN (t))
4415     /* If the function does not take a variable number of arguments,
4416        the last element in the list will have type `void'.  */
4417     if (VOID_TYPE_P (TREE_VALUE (t)))
4418       break;
4419     else
4420       ++i;
4421
4422   return i;
4423 }
4424
4425 /* Nonzero if integer constants T1 and T2
4426    represent the same constant value.  */
4427
4428 int
4429 tree_int_cst_equal (tree t1, tree t2)
4430 {
4431   if (t1 == t2)
4432     return 1;
4433
4434   if (t1 == 0 || t2 == 0)
4435     return 0;
4436
4437   if (TREE_CODE (t1) == INTEGER_CST
4438       && TREE_CODE (t2) == INTEGER_CST
4439       && TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
4440       && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2))
4441     return 1;
4442
4443   return 0;
4444 }
4445
4446 /* Nonzero if integer constants T1 and T2 represent values that satisfy <.
4447    The precise way of comparison depends on their data type.  */
4448
4449 int
4450 tree_int_cst_lt (tree t1, tree t2)
4451 {
4452   if (t1 == t2)
4453     return 0;
4454
4455   if (TYPE_UNSIGNED (TREE_TYPE (t1)) != TYPE_UNSIGNED (TREE_TYPE (t2)))
4456     {
4457       int t1_sgn = tree_int_cst_sgn (t1);
4458       int t2_sgn = tree_int_cst_sgn (t2);
4459
4460       if (t1_sgn < t2_sgn)
4461         return 1;
4462       else if (t1_sgn > t2_sgn)
4463         return 0;
4464       /* Otherwise, both are non-negative, so we compare them as
4465          unsigned just in case one of them would overflow a signed
4466          type.  */
4467     }
4468   else if (!TYPE_UNSIGNED (TREE_TYPE (t1)))
4469     return INT_CST_LT (t1, t2);
4470
4471   return INT_CST_LT_UNSIGNED (t1, t2);
4472 }
4473
4474 /* Returns -1 if T1 < T2, 0 if T1 == T2, and 1 if T1 > T2.  */
4475
4476 int
4477 tree_int_cst_compare (tree t1, tree t2)
4478 {
4479   if (tree_int_cst_lt (t1, t2))
4480     return -1;
4481   else if (tree_int_cst_lt (t2, t1))
4482     return 1;
4483   else
4484     return 0;
4485 }
4486
4487 /* Return 1 if T is an INTEGER_CST that can be manipulated efficiently on
4488    the host.  If POS is zero, the value can be represented in a single
4489    HOST_WIDE_INT.  If POS is nonzero, the value must be non-negative and can
4490    be represented in a single unsigned HOST_WIDE_INT.  */
4491
4492 int
4493 host_integerp (tree t, int pos)
4494 {
4495   return (TREE_CODE (t) == INTEGER_CST
4496           && ((TREE_INT_CST_HIGH (t) == 0
4497                && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) >= 0)
4498               || (! pos && TREE_INT_CST_HIGH (t) == -1
4499                   && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0
4500                   && !TYPE_UNSIGNED (TREE_TYPE (t)))
4501               || (pos && TREE_INT_CST_HIGH (t) == 0)));
4502 }
4503
4504 /* Return the HOST_WIDE_INT least significant bits of T if it is an
4505    INTEGER_CST and there is no overflow.  POS is nonzero if the result must
4506    be non-negative.  We must be able to satisfy the above conditions.  */
4507
4508 HOST_WIDE_INT
4509 tree_low_cst (tree t, int pos)
4510 {
4511   gcc_assert (host_integerp (t, pos));
4512   return TREE_INT_CST_LOW (t);
4513 }
4514
4515 /* Return the most significant bit of the integer constant T.  */
4516
4517 int
4518 tree_int_cst_msb (tree t)
4519 {
4520   int prec;
4521   HOST_WIDE_INT h;
4522   unsigned HOST_WIDE_INT l;
4523
4524   /* Note that using TYPE_PRECISION here is wrong.  We care about the
4525      actual bits, not the (arbitrary) range of the type.  */
4526   prec = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (t))) - 1;
4527   rshift_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t), prec,
4528                  2 * HOST_BITS_PER_WIDE_INT, &l, &h, 0);
4529   return (l & 1) == 1;
4530 }
4531
4532 /* Return an indication of the sign of the integer constant T.
4533    The return value is -1 if T < 0, 0 if T == 0, and 1 if T > 0.
4534    Note that -1 will never be returned if T's type is unsigned.  */
4535
4536 int
4537 tree_int_cst_sgn (tree t)
4538 {
4539   if (TREE_INT_CST_LOW (t) == 0 && TREE_INT_CST_HIGH (t) == 0)
4540     return 0;
4541   else if (TYPE_UNSIGNED (TREE_TYPE (t)))
4542     return 1;
4543   else if (TREE_INT_CST_HIGH (t) < 0)
4544     return -1;
4545   else
4546     return 1;
4547 }
4548
4549 /* Compare two constructor-element-type constants.  Return 1 if the lists
4550    are known to be equal; otherwise return 0.  */
4551
4552 int
4553 simple_cst_list_equal (tree l1, tree l2)
4554 {
4555   while (l1 != NULL_TREE && l2 != NULL_TREE)
4556     {
4557       if (simple_cst_equal (TREE_VALUE (l1), TREE_VALUE (l2)) != 1)
4558         return 0;
4559
4560       l1 = TREE_CHAIN (l1);
4561       l2 = TREE_CHAIN (l2);
4562     }
4563
4564   return l1 == l2;
4565 }
4566
4567 /* Return truthvalue of whether T1 is the same tree structure as T2.
4568    Return 1 if they are the same.
4569    Return 0 if they are understandably different.
4570    Return -1 if either contains tree structure not understood by
4571    this function.  */
4572
4573 int
4574 simple_cst_equal (tree t1, tree t2)
4575 {
4576   enum tree_code code1, code2;
4577   int cmp;
4578   int i;
4579
4580   if (t1 == t2)
4581     return 1;
4582   if (t1 == 0 || t2 == 0)
4583     return 0;
4584
4585   code1 = TREE_CODE (t1);
4586   code2 = TREE_CODE (t2);
4587
4588   if (code1 == NOP_EXPR || code1 == CONVERT_EXPR || code1 == NON_LVALUE_EXPR)
4589     {
4590       if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
4591           || code2 == NON_LVALUE_EXPR)
4592         return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4593       else
4594         return simple_cst_equal (TREE_OPERAND (t1, 0), t2);
4595     }
4596
4597   else if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
4598            || code2 == NON_LVALUE_EXPR)
4599     return simple_cst_equal (t1, TREE_OPERAND (t2, 0));
4600
4601   if (code1 != code2)
4602     return 0;
4603
4604   switch (code1)
4605     {
4606     case INTEGER_CST:
4607       return (TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
4608               && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2));
4609
4610     case REAL_CST:
4611       return REAL_VALUES_IDENTICAL (TREE_REAL_CST (t1), TREE_REAL_CST (t2));
4612
4613     case STRING_CST:
4614       return (TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
4615               && ! memcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2),
4616                          TREE_STRING_LENGTH (t1)));
4617
4618     case CONSTRUCTOR:
4619       {
4620         unsigned HOST_WIDE_INT idx;
4621         VEC(constructor_elt, gc) *v1 = CONSTRUCTOR_ELTS (t1);
4622         VEC(constructor_elt, gc) *v2 = CONSTRUCTOR_ELTS (t2);
4623
4624         if (VEC_length (constructor_elt, v1) != VEC_length (constructor_elt, v2))
4625           return false;
4626
4627         for (idx = 0; idx < VEC_length (constructor_elt, v1); ++idx)
4628           /* ??? Should we handle also fields here? */
4629           if (!simple_cst_equal (VEC_index (constructor_elt, v1, idx)->value,
4630                                  VEC_index (constructor_elt, v2, idx)->value))
4631             return false;
4632         return true;
4633       }
4634
4635     case SAVE_EXPR:
4636       return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4637
4638     case CALL_EXPR:
4639       cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4640       if (cmp <= 0)
4641         return cmp;
4642       return
4643         simple_cst_list_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
4644
4645     case TARGET_EXPR:
4646       /* Special case: if either target is an unallocated VAR_DECL,
4647          it means that it's going to be unified with whatever the
4648          TARGET_EXPR is really supposed to initialize, so treat it
4649          as being equivalent to anything.  */
4650       if ((TREE_CODE (TREE_OPERAND (t1, 0)) == VAR_DECL
4651            && DECL_NAME (TREE_OPERAND (t1, 0)) == NULL_TREE
4652            && !DECL_RTL_SET_P (TREE_OPERAND (t1, 0)))
4653           || (TREE_CODE (TREE_OPERAND (t2, 0)) == VAR_DECL
4654               && DECL_NAME (TREE_OPERAND (t2, 0)) == NULL_TREE
4655               && !DECL_RTL_SET_P (TREE_OPERAND (t2, 0))))
4656         cmp = 1;
4657       else
4658         cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4659
4660       if (cmp <= 0)
4661         return cmp;
4662
4663       return simple_cst_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
4664
4665     case WITH_CLEANUP_EXPR:
4666       cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4667       if (cmp <= 0)
4668         return cmp;
4669
4670       return simple_cst_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t1, 1));
4671
4672     case COMPONENT_REF:
4673       if (TREE_OPERAND (t1, 1) == TREE_OPERAND (t2, 1))
4674         return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4675
4676       return 0;
4677
4678     case VAR_DECL:
4679     case PARM_DECL:
4680     case CONST_DECL:
4681     case FUNCTION_DECL:
4682       return 0;
4683
4684     default:
4685       break;
4686     }
4687
4688   /* This general rule works for most tree codes.  All exceptions should be
4689      handled above.  If this is a language-specific tree code, we can't
4690      trust what might be in the operand, so say we don't know
4691      the situation.  */
4692   if ((int) code1 >= (int) LAST_AND_UNUSED_TREE_CODE)
4693     return -1;
4694
4695   switch (TREE_CODE_CLASS (code1))
4696     {
4697     case tcc_unary:
4698     case tcc_binary:
4699     case tcc_comparison:
4700     case tcc_expression:
4701     case tcc_reference:
4702     case tcc_statement:
4703       cmp = 1;
4704       for (i = 0; i < TREE_CODE_LENGTH (code1); i++)
4705         {
4706           cmp = simple_cst_equal (TREE_OPERAND (t1, i), TREE_OPERAND (t2, i));
4707           if (cmp <= 0)
4708             return cmp;
4709         }
4710
4711       return cmp;
4712
4713     default:
4714       return -1;
4715     }
4716 }
4717
4718 /* Compare the value of T, an INTEGER_CST, with U, an unsigned integer value.
4719    Return -1, 0, or 1 if the value of T is less than, equal to, or greater
4720    than U, respectively.  */
4721
4722 int
4723 compare_tree_int (tree t, unsigned HOST_WIDE_INT u)
4724 {
4725   if (tree_int_cst_sgn (t) < 0)
4726     return -1;
4727   else if (TREE_INT_CST_HIGH (t) != 0)
4728     return 1;
4729   else if (TREE_INT_CST_LOW (t) == u)
4730     return 0;
4731   else if (TREE_INT_CST_LOW (t) < u)
4732     return -1;
4733   else
4734     return 1;
4735 }
4736
4737 /* Return true if CODE represents an associative tree code.  Otherwise
4738    return false.  */
4739 bool
4740 associative_tree_code (enum tree_code code)
4741 {
4742   switch (code)
4743     {
4744     case BIT_IOR_EXPR:
4745     case BIT_AND_EXPR:
4746     case BIT_XOR_EXPR:
4747     case PLUS_EXPR:
4748     case MULT_EXPR:
4749     case MIN_EXPR:
4750     case MAX_EXPR:
4751       return true;
4752
4753     default:
4754       break;
4755     }
4756   return false;
4757 }
4758
4759 /* Return true if CODE represents a commutative tree code.  Otherwise
4760    return false.  */
4761 bool
4762 commutative_tree_code (enum tree_code code)
4763 {
4764   switch (code)
4765     {
4766     case PLUS_EXPR:
4767     case MULT_EXPR:
4768     case MIN_EXPR:
4769     case MAX_EXPR:
4770     case BIT_IOR_EXPR:
4771     case BIT_XOR_EXPR:
4772     case BIT_AND_EXPR:
4773     case NE_EXPR:
4774     case EQ_EXPR:
4775     case UNORDERED_EXPR:
4776     case ORDERED_EXPR:
4777     case UNEQ_EXPR:
4778     case LTGT_EXPR:
4779     case TRUTH_AND_EXPR:
4780     case TRUTH_XOR_EXPR:
4781     case TRUTH_OR_EXPR:
4782       return true;
4783
4784     default:
4785       break;
4786     }
4787   return false;
4788 }
4789
4790 /* Generate a hash value for an expression.  This can be used iteratively
4791    by passing a previous result as the "val" argument.
4792
4793    This function is intended to produce the same hash for expressions which
4794    would compare equal using operand_equal_p.  */
4795
4796 hashval_t
4797 iterative_hash_expr (tree t, hashval_t val)
4798 {
4799   int i;
4800   enum tree_code code;
4801   char class;
4802
4803   if (t == NULL_TREE)
4804     return iterative_hash_pointer (t, val);
4805
4806   code = TREE_CODE (t);
4807
4808   switch (code)
4809     {
4810     /* Alas, constants aren't shared, so we can't rely on pointer
4811        identity.  */
4812     case INTEGER_CST:
4813       val = iterative_hash_host_wide_int (TREE_INT_CST_LOW (t), val);
4814       return iterative_hash_host_wide_int (TREE_INT_CST_HIGH (t), val);
4815     case REAL_CST:
4816       {
4817         unsigned int val2 = real_hash (TREE_REAL_CST_PTR (t));
4818
4819         return iterative_hash_hashval_t (val2, val);
4820       }
4821     case STRING_CST:
4822       return iterative_hash (TREE_STRING_POINTER (t),
4823                              TREE_STRING_LENGTH (t), val);
4824     case COMPLEX_CST:
4825       val = iterative_hash_expr (TREE_REALPART (t), val);
4826       return iterative_hash_expr (TREE_IMAGPART (t), val);
4827     case VECTOR_CST:
4828       return iterative_hash_expr (TREE_VECTOR_CST_ELTS (t), val);
4829
4830     case SSA_NAME:
4831     case VALUE_HANDLE:
4832       /* we can just compare by pointer.  */
4833       return iterative_hash_pointer (t, val);
4834
4835     case TREE_LIST:
4836       /* A list of expressions, for a CALL_EXPR or as the elements of a
4837          VECTOR_CST.  */
4838       for (; t; t = TREE_CHAIN (t))
4839         val = iterative_hash_expr (TREE_VALUE (t), val);
4840       return val;
4841     case CONSTRUCTOR:
4842       {
4843         unsigned HOST_WIDE_INT idx;
4844         tree field, value;
4845         FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), idx, field, value)
4846           {
4847             val = iterative_hash_expr (field, val);
4848             val = iterative_hash_expr (value, val);
4849           }
4850         return val;
4851       }
4852     case FUNCTION_DECL:
4853       /* When referring to a built-in FUNCTION_DECL, use the
4854          __builtin__ form.  Otherwise nodes that compare equal
4855          according to operand_equal_p might get different
4856          hash codes.  */
4857       if (DECL_BUILT_IN (t))
4858         {
4859           val = iterative_hash_pointer (built_in_decls[DECL_FUNCTION_CODE (t)],
4860                                       val);
4861           return val;
4862         }
4863       /* else FALL THROUGH */
4864     default:
4865       class = TREE_CODE_CLASS (code);
4866
4867       if (class == tcc_declaration)
4868         {
4869           /* DECL's have a unique ID */
4870           val = iterative_hash_host_wide_int (DECL_UID (t), val);
4871         }
4872       else
4873         {
4874           gcc_assert (IS_EXPR_CODE_CLASS (class));
4875
4876           val = iterative_hash_object (code, val);
4877
4878           /* Don't hash the type, that can lead to having nodes which
4879              compare equal according to operand_equal_p, but which
4880              have different hash codes.  */
4881           if (code == NOP_EXPR
4882               || code == CONVERT_EXPR
4883               || code == NON_LVALUE_EXPR)
4884             {
4885               /* Make sure to include signness in the hash computation.  */
4886               val += TYPE_UNSIGNED (TREE_TYPE (t));
4887               val = iterative_hash_expr (TREE_OPERAND (t, 0), val);
4888             }
4889
4890           else if (commutative_tree_code (code))
4891             {
4892               /* It's a commutative expression.  We want to hash it the same
4893                  however it appears.  We do this by first hashing both operands
4894                  and then rehashing based on the order of their independent
4895                  hashes.  */
4896               hashval_t one = iterative_hash_expr (TREE_OPERAND (t, 0), 0);
4897               hashval_t two = iterative_hash_expr (TREE_OPERAND (t, 1), 0);
4898               hashval_t t;
4899
4900               if (one > two)
4901                 t = one, one = two, two = t;
4902
4903               val = iterative_hash_hashval_t (one, val);
4904               val = iterative_hash_hashval_t (two, val);
4905             }
4906           else
4907             for (i = TREE_CODE_LENGTH (code) - 1; i >= 0; --i)
4908               val = iterative_hash_expr (TREE_OPERAND (t, i), val);
4909         }
4910       return val;
4911       break;
4912     }
4913 }
4914 \f
4915 /* Constructors for pointer, array and function types.
4916    (RECORD_TYPE, UNION_TYPE and ENUMERAL_TYPE nodes are
4917    constructed by language-dependent code, not here.)  */
4918
4919 /* Construct, lay out and return the type of pointers to TO_TYPE with
4920    mode MODE.  If CAN_ALIAS_ALL is TRUE, indicate this type can
4921    reference all of memory. If such a type has already been
4922    constructed, reuse it.  */
4923
4924 tree
4925 build_pointer_type_for_mode (tree to_type, enum machine_mode mode,
4926                              bool can_alias_all)
4927 {
4928   tree t;
4929
4930   if (to_type == error_mark_node)
4931     return error_mark_node;
4932
4933   /* In some cases, languages will have things that aren't a POINTER_TYPE
4934      (such as a RECORD_TYPE for fat pointers in Ada) as TYPE_POINTER_TO.
4935      In that case, return that type without regard to the rest of our
4936      operands.
4937
4938      ??? This is a kludge, but consistent with the way this function has
4939      always operated and there doesn't seem to be a good way to avoid this
4940      at the moment.  */
4941   if (TYPE_POINTER_TO (to_type) != 0
4942       && TREE_CODE (TYPE_POINTER_TO (to_type)) != POINTER_TYPE)
4943     return TYPE_POINTER_TO (to_type);
4944
4945   /* First, if we already have a type for pointers to TO_TYPE and it's
4946      the proper mode, use it.  */
4947   for (t = TYPE_POINTER_TO (to_type); t; t = TYPE_NEXT_PTR_TO (t))
4948     if (TYPE_MODE (t) == mode && TYPE_REF_CAN_ALIAS_ALL (t) == can_alias_all)
4949       return t;
4950
4951   t = make_node (POINTER_TYPE);
4952
4953   TREE_TYPE (t) = to_type;
4954   TYPE_MODE (t) = mode;
4955   TYPE_REF_CAN_ALIAS_ALL (t) = can_alias_all;
4956   TYPE_NEXT_PTR_TO (t) = TYPE_POINTER_TO (to_type);
4957   TYPE_POINTER_TO (to_type) = t;
4958
4959   /* Lay out the type.  This function has many callers that are concerned
4960      with expression-construction, and this simplifies them all.  */
4961   layout_type (t);
4962
4963   return t;
4964 }
4965
4966 /* By default build pointers in ptr_mode.  */
4967
4968 tree
4969 build_pointer_type (tree to_type)
4970 {
4971   return build_pointer_type_for_mode (to_type, ptr_mode, false);
4972 }
4973
4974 /* Same as build_pointer_type_for_mode, but for REFERENCE_TYPE.  */
4975
4976 tree
4977 build_reference_type_for_mode (tree to_type, enum machine_mode mode,
4978                                bool can_alias_all)
4979 {
4980   tree t;
4981
4982   /* In some cases, languages will have things that aren't a REFERENCE_TYPE
4983      (such as a RECORD_TYPE for fat pointers in Ada) as TYPE_REFERENCE_TO.
4984      In that case, return that type without regard to the rest of our
4985      operands.
4986
4987      ??? This is a kludge, but consistent with the way this function has
4988      always operated and there doesn't seem to be a good way to avoid this
4989      at the moment.  */
4990   if (TYPE_REFERENCE_TO (to_type) != 0
4991       && TREE_CODE (TYPE_REFERENCE_TO (to_type)) != REFERENCE_TYPE)
4992     return TYPE_REFERENCE_TO (to_type);
4993
4994   /* First, if we already have a type for pointers to TO_TYPE and it's
4995      the proper mode, use it.  */
4996   for (t = TYPE_REFERENCE_TO (to_type); t; t = TYPE_NEXT_REF_TO (t))
4997     if (TYPE_MODE (t) == mode && TYPE_REF_CAN_ALIAS_ALL (t) == can_alias_all)
4998       return t;
4999
5000   t = make_node (REFERENCE_TYPE);
5001
5002   TREE_TYPE (t) = to_type;
5003   TYPE_MODE (t) = mode;
5004   TYPE_REF_CAN_ALIAS_ALL (t) = can_alias_all;
5005   TYPE_NEXT_REF_TO (t) = TYPE_REFERENCE_TO (to_type);
5006   TYPE_REFERENCE_TO (to_type) = t;
5007
5008   layout_type (t);
5009
5010   return t;
5011 }
5012
5013
5014 /* Build the node for the type of references-to-TO_TYPE by default
5015    in ptr_mode.  */
5016
5017 tree
5018 build_reference_type (tree to_type)
5019 {
5020   return build_reference_type_for_mode (to_type, ptr_mode, false);
5021 }
5022
5023 /* Build a type that is compatible with t but has no cv quals anywhere
5024    in its type, thus
5025
5026    const char *const *const *  ->  char ***.  */
5027
5028 tree
5029 build_type_no_quals (tree t)
5030 {
5031   switch (TREE_CODE (t))
5032     {
5033     case POINTER_TYPE:
5034       return build_pointer_type_for_mode (build_type_no_quals (TREE_TYPE (t)),
5035                                           TYPE_MODE (t),
5036                                           TYPE_REF_CAN_ALIAS_ALL (t));
5037     case REFERENCE_TYPE:
5038       return
5039         build_reference_type_for_mode (build_type_no_quals (TREE_TYPE (t)),
5040                                        TYPE_MODE (t),
5041                                        TYPE_REF_CAN_ALIAS_ALL (t));
5042     default:
5043       return TYPE_MAIN_VARIANT (t);
5044     }
5045 }
5046
5047 /* Create a type of integers to be the TYPE_DOMAIN of an ARRAY_TYPE.
5048    MAXVAL should be the maximum value in the domain
5049    (one less than the length of the array).
5050
5051    The maximum value that MAXVAL can have is INT_MAX for a HOST_WIDE_INT.
5052    We don't enforce this limit, that is up to caller (e.g. language front end).
5053    The limit exists because the result is a signed type and we don't handle
5054    sizes that use more than one HOST_WIDE_INT.  */
5055
5056 tree
5057 build_index_type (tree maxval)
5058 {
5059   tree itype = make_node (INTEGER_TYPE);
5060
5061   TREE_TYPE (itype) = sizetype;
5062   TYPE_PRECISION (itype) = TYPE_PRECISION (sizetype);
5063   TYPE_MIN_VALUE (itype) = size_zero_node;
5064   TYPE_MAX_VALUE (itype) = fold_convert (sizetype, maxval);
5065   TYPE_MODE (itype) = TYPE_MODE (sizetype);
5066   TYPE_SIZE (itype) = TYPE_SIZE (sizetype);
5067   TYPE_SIZE_UNIT (itype) = TYPE_SIZE_UNIT (sizetype);
5068   TYPE_ALIGN (itype) = TYPE_ALIGN (sizetype);
5069   TYPE_USER_ALIGN (itype) = TYPE_USER_ALIGN (sizetype);
5070
5071   if (host_integerp (maxval, 1))
5072     return type_hash_canon (tree_low_cst (maxval, 1), itype);
5073   else
5074     return itype;
5075 }
5076
5077 /* Builds a signed or unsigned integer type of precision PRECISION.
5078    Used for C bitfields whose precision does not match that of
5079    built-in target types.  */
5080 tree
5081 build_nonstandard_integer_type (unsigned HOST_WIDE_INT precision,
5082                                 int unsignedp)
5083 {
5084   tree itype = make_node (INTEGER_TYPE);
5085
5086   TYPE_PRECISION (itype) = precision;
5087
5088   if (unsignedp)
5089     fixup_unsigned_type (itype);
5090   else
5091     fixup_signed_type (itype);
5092
5093   if (host_integerp (TYPE_MAX_VALUE (itype), 1))
5094     return type_hash_canon (tree_low_cst (TYPE_MAX_VALUE (itype), 1), itype);
5095
5096   return itype;
5097 }
5098
5099 /* Create a range of some discrete type TYPE (an INTEGER_TYPE,
5100    ENUMERAL_TYPE or BOOLEAN_TYPE), with low bound LOWVAL and
5101    high bound HIGHVAL.  If TYPE is NULL, sizetype is used.  */
5102
5103 tree
5104 build_range_type (tree type, tree lowval, tree highval)
5105 {
5106   tree itype = make_node (INTEGER_TYPE);
5107
5108   TREE_TYPE (itype) = type;
5109   if (type == NULL_TREE)
5110     type = sizetype;
5111
5112   TYPE_MIN_VALUE (itype) = fold_convert (type, lowval);
5113   TYPE_MAX_VALUE (itype) = highval ? fold_convert (type, highval) : NULL;
5114
5115   TYPE_PRECISION (itype) = TYPE_PRECISION (type);
5116   TYPE_MODE (itype) = TYPE_MODE (type);
5117   TYPE_SIZE (itype) = TYPE_SIZE (type);
5118   TYPE_SIZE_UNIT (itype) = TYPE_SIZE_UNIT (type);
5119   TYPE_ALIGN (itype) = TYPE_ALIGN (type);
5120   TYPE_USER_ALIGN (itype) = TYPE_USER_ALIGN (type);
5121
5122   if (host_integerp (lowval, 0) && highval != 0 && host_integerp (highval, 0))
5123     return type_hash_canon (tree_low_cst (highval, 0)
5124                             - tree_low_cst (lowval, 0),
5125                             itype);
5126   else
5127     return itype;
5128 }
5129
5130 /* Just like build_index_type, but takes lowval and highval instead
5131    of just highval (maxval).  */
5132
5133 tree
5134 build_index_2_type (tree lowval, tree highval)
5135 {
5136   return build_range_type (sizetype, lowval, highval);
5137 }
5138
5139 /* Construct, lay out and return the type of arrays of elements with ELT_TYPE
5140    and number of elements specified by the range of values of INDEX_TYPE.
5141    If such a type has already been constructed, reuse it.  */
5142
5143 tree
5144 build_array_type (tree elt_type, tree index_type)
5145 {
5146   tree t;
5147   hashval_t hashcode = 0;
5148
5149   if (TREE_CODE (elt_type) == FUNCTION_TYPE)
5150     {
5151       error ("arrays of functions are not meaningful");
5152       elt_type = integer_type_node;
5153     }
5154
5155   t = make_node (ARRAY_TYPE);
5156   TREE_TYPE (t) = elt_type;
5157   TYPE_DOMAIN (t) = index_type;
5158
5159   if (index_type == 0)
5160     {
5161       layout_type (t);
5162       return t;
5163     }
5164
5165   hashcode = iterative_hash_object (TYPE_HASH (elt_type), hashcode);
5166   hashcode = iterative_hash_object (TYPE_HASH (index_type), hashcode);
5167   t = type_hash_canon (hashcode, t);
5168
5169   if (!COMPLETE_TYPE_P (t))
5170     layout_type (t);
5171   return t;
5172 }
5173
5174 /* Return the TYPE of the elements comprising
5175    the innermost dimension of ARRAY.  */
5176
5177 tree
5178 get_inner_array_type (tree array)
5179 {
5180   tree type = TREE_TYPE (array);
5181
5182   while (TREE_CODE (type) == ARRAY_TYPE)
5183     type = TREE_TYPE (type);
5184
5185   return type;
5186 }
5187
5188 /* Construct, lay out and return
5189    the type of functions returning type VALUE_TYPE
5190    given arguments of types ARG_TYPES.
5191    ARG_TYPES is a chain of TREE_LIST nodes whose TREE_VALUEs
5192    are data type nodes for the arguments of the function.
5193    If such a type has already been constructed, reuse it.  */
5194
5195 tree
5196 build_function_type (tree value_type, tree arg_types)
5197 {
5198   tree t;
5199   hashval_t hashcode = 0;
5200
5201   if (TREE_CODE (value_type) == FUNCTION_TYPE)
5202     {
5203       error ("function return type cannot be function");
5204       value_type = integer_type_node;
5205     }
5206
5207   /* Make a node of the sort we want.  */
5208   t = make_node (FUNCTION_TYPE);
5209   TREE_TYPE (t) = value_type;
5210   TYPE_ARG_TYPES (t) = arg_types;
5211
5212   /* If we already have such a type, use the old one.  */
5213   hashcode = iterative_hash_object (TYPE_HASH (value_type), hashcode);
5214   hashcode = type_hash_list (arg_types, hashcode);
5215   t = type_hash_canon (hashcode, t);
5216
5217   if (!COMPLETE_TYPE_P (t))
5218     layout_type (t);
5219   return t;
5220 }
5221
5222 /* Build a function type.  The RETURN_TYPE is the type returned by the
5223    function.  If additional arguments are provided, they are
5224    additional argument types.  The list of argument types must always
5225    be terminated by NULL_TREE.  */
5226
5227 tree
5228 build_function_type_list (tree return_type, ...)
5229 {
5230   tree t, args, last;
5231   va_list p;
5232
5233   va_start (p, return_type);
5234
5235   t = va_arg (p, tree);
5236   for (args = NULL_TREE; t != NULL_TREE; t = va_arg (p, tree))
5237     args = tree_cons (NULL_TREE, t, args);
5238
5239   if (args == NULL_TREE)
5240     args = void_list_node;
5241   else
5242     {
5243       last = args;
5244       args = nreverse (args);
5245       TREE_CHAIN (last) = void_list_node;
5246     }
5247   args = build_function_type (return_type, args);
5248
5249   va_end (p);
5250   return args;
5251 }
5252
5253 /* Build a METHOD_TYPE for a member of BASETYPE.  The RETTYPE (a TYPE)
5254    and ARGTYPES (a TREE_LIST) are the return type and arguments types
5255    for the method.  An implicit additional parameter (of type
5256    pointer-to-BASETYPE) is added to the ARGTYPES.  */
5257
5258 tree
5259 build_method_type_directly (tree basetype,
5260                             tree rettype,
5261                             tree argtypes)
5262 {
5263   tree t;
5264   tree ptype;
5265   int hashcode = 0;
5266
5267   /* Make a node of the sort we want.  */
5268   t = make_node (METHOD_TYPE);
5269
5270   TYPE_METHOD_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
5271   TREE_TYPE (t) = rettype;
5272   ptype = build_pointer_type (basetype);
5273
5274   /* The actual arglist for this function includes a "hidden" argument
5275      which is "this".  Put it into the list of argument types.  */
5276   argtypes = tree_cons (NULL_TREE, ptype, argtypes);
5277   TYPE_ARG_TYPES (t) = argtypes;
5278
5279   /* If we already have such a type, use the old one.  */
5280   hashcode = iterative_hash_object (TYPE_HASH (basetype), hashcode);
5281   hashcode = iterative_hash_object (TYPE_HASH (rettype), hashcode);
5282   hashcode = type_hash_list (argtypes, hashcode);
5283   t = type_hash_canon (hashcode, t);
5284
5285   if (!COMPLETE_TYPE_P (t))
5286     layout_type (t);
5287
5288   return t;
5289 }
5290
5291 /* Construct, lay out and return the type of methods belonging to class
5292    BASETYPE and whose arguments and values are described by TYPE.
5293    If that type exists already, reuse it.
5294    TYPE must be a FUNCTION_TYPE node.  */
5295
5296 tree
5297 build_method_type (tree basetype, tree type)
5298 {
5299   gcc_assert (TREE_CODE (type) == FUNCTION_TYPE);
5300
5301   return build_method_type_directly (basetype,
5302                                      TREE_TYPE (type),
5303                                      TYPE_ARG_TYPES (type));
5304 }
5305
5306 /* Construct, lay out and return the type of offsets to a value
5307    of type TYPE, within an object of type BASETYPE.
5308    If a suitable offset type exists already, reuse it.  */
5309
5310 tree
5311 build_offset_type (tree basetype, tree type)
5312 {
5313   tree t;
5314   hashval_t hashcode = 0;
5315
5316   /* Make a node of the sort we want.  */
5317   t = make_node (OFFSET_TYPE);
5318
5319   TYPE_OFFSET_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
5320   TREE_TYPE (t) = type;
5321
5322   /* If we already have such a type, use the old one.  */
5323   hashcode = iterative_hash_object (TYPE_HASH (basetype), hashcode);
5324   hashcode = iterative_hash_object (TYPE_HASH (type), hashcode);
5325   t = type_hash_canon (hashcode, t);
5326
5327   if (!COMPLETE_TYPE_P (t))
5328     layout_type (t);
5329
5330   return t;
5331 }
5332
5333 /* Create a complex type whose components are COMPONENT_TYPE.  */
5334
5335 tree
5336 build_complex_type (tree component_type)
5337 {
5338   tree t;
5339   hashval_t hashcode;
5340
5341   /* Make a node of the sort we want.  */
5342   t = make_node (COMPLEX_TYPE);
5343
5344   TREE_TYPE (t) = TYPE_MAIN_VARIANT (component_type);
5345
5346   /* If we already have such a type, use the old one.  */
5347   hashcode = iterative_hash_object (TYPE_HASH (component_type), 0);
5348   t = type_hash_canon (hashcode, t);
5349
5350   if (!COMPLETE_TYPE_P (t))
5351     layout_type (t);
5352
5353   /* If we are writing Dwarf2 output we need to create a name,
5354      since complex is a fundamental type.  */
5355   if ((write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
5356       && ! TYPE_NAME (t))
5357     {
5358       const char *name;
5359       if (component_type == char_type_node)
5360         name = "complex char";
5361       else if (component_type == signed_char_type_node)
5362         name = "complex signed char";
5363       else if (component_type == unsigned_char_type_node)
5364         name = "complex unsigned char";
5365       else if (component_type == short_integer_type_node)
5366         name = "complex short int";
5367       else if (component_type == short_unsigned_type_node)
5368         name = "complex short unsigned int";
5369       else if (component_type == integer_type_node)
5370         name = "complex int";
5371       else if (component_type == unsigned_type_node)
5372         name = "complex unsigned int";
5373       else if (component_type == long_integer_type_node)
5374         name = "complex long int";
5375       else if (component_type == long_unsigned_type_node)
5376         name = "complex long unsigned int";
5377       else if (component_type == long_long_integer_type_node)
5378         name = "complex long long int";
5379       else if (component_type == long_long_unsigned_type_node)
5380         name = "complex long long unsigned int";
5381       else
5382         name = 0;
5383
5384       if (name != 0)
5385         TYPE_NAME (t) = get_identifier (name);
5386     }
5387
5388   return build_qualified_type (t, TYPE_QUALS (component_type));
5389 }
5390 \f
5391 /* Return OP, stripped of any conversions to wider types as much as is safe.
5392    Converting the value back to OP's type makes a value equivalent to OP.
5393
5394    If FOR_TYPE is nonzero, we return a value which, if converted to
5395    type FOR_TYPE, would be equivalent to converting OP to type FOR_TYPE.
5396
5397    If FOR_TYPE is nonzero, unaligned bit-field references may be changed to the
5398    narrowest type that can hold the value, even if they don't exactly fit.
5399    Otherwise, bit-field references are changed to a narrower type
5400    only if they can be fetched directly from memory in that type.
5401
5402    OP must have integer, real or enumeral type.  Pointers are not allowed!
5403
5404    There are some cases where the obvious value we could return
5405    would regenerate to OP if converted to OP's type,
5406    but would not extend like OP to wider types.
5407    If FOR_TYPE indicates such extension is contemplated, we eschew such values.
5408    For example, if OP is (unsigned short)(signed char)-1,
5409    we avoid returning (signed char)-1 if FOR_TYPE is int,
5410    even though extending that to an unsigned short would regenerate OP,
5411    since the result of extending (signed char)-1 to (int)
5412    is different from (int) OP.  */
5413
5414 tree
5415 get_unwidened (tree op, tree for_type)
5416 {
5417   /* Set UNS initially if converting OP to FOR_TYPE is a zero-extension.  */
5418   tree type = TREE_TYPE (op);
5419   unsigned final_prec
5420     = TYPE_PRECISION (for_type != 0 ? for_type : type);
5421   int uns
5422     = (for_type != 0 && for_type != type
5423        && final_prec > TYPE_PRECISION (type)
5424        && TYPE_UNSIGNED (type));
5425   tree win = op;
5426
5427   while (TREE_CODE (op) == NOP_EXPR
5428          || TREE_CODE (op) == CONVERT_EXPR)
5429     {
5430       int bitschange;
5431
5432       /* TYPE_PRECISION on vector types has different meaning
5433          (TYPE_VECTOR_SUBPARTS) and casts from vectors are view conversions,
5434          so avoid them here.  */
5435       if (TREE_CODE (TREE_TYPE (TREE_OPERAND (op, 0))) == VECTOR_TYPE)
5436         break;
5437
5438       bitschange = TYPE_PRECISION (TREE_TYPE (op))
5439                    - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0)));
5440
5441       /* Truncations are many-one so cannot be removed.
5442          Unless we are later going to truncate down even farther.  */
5443       if (bitschange < 0
5444           && final_prec > TYPE_PRECISION (TREE_TYPE (op)))
5445         break;
5446
5447       /* See what's inside this conversion.  If we decide to strip it,
5448          we will set WIN.  */
5449       op = TREE_OPERAND (op, 0);
5450
5451       /* If we have not stripped any zero-extensions (uns is 0),
5452          we can strip any kind of extension.
5453          If we have previously stripped a zero-extension,
5454          only zero-extensions can safely be stripped.
5455          Any extension can be stripped if the bits it would produce
5456          are all going to be discarded later by truncating to FOR_TYPE.  */
5457
5458       if (bitschange > 0)
5459         {
5460           if (! uns || final_prec <= TYPE_PRECISION (TREE_TYPE (op)))
5461             win = op;
5462           /* TYPE_UNSIGNED says whether this is a zero-extension.
5463              Let's avoid computing it if it does not affect WIN
5464              and if UNS will not be needed again.  */
5465           if ((uns
5466                || TREE_CODE (op) == NOP_EXPR
5467                || TREE_CODE (op) == CONVERT_EXPR)
5468               && TYPE_UNSIGNED (TREE_TYPE (op)))
5469             {
5470               uns = 1;
5471               win = op;
5472             }
5473         }
5474     }
5475
5476   if (TREE_CODE (op) == COMPONENT_REF
5477       /* Since type_for_size always gives an integer type.  */
5478       && TREE_CODE (type) != REAL_TYPE
5479       /* Don't crash if field not laid out yet.  */
5480       && DECL_SIZE (TREE_OPERAND (op, 1)) != 0
5481       && host_integerp (DECL_SIZE (TREE_OPERAND (op, 1)), 1))
5482     {
5483       unsigned int innerprec
5484         = tree_low_cst (DECL_SIZE (TREE_OPERAND (op, 1)), 1);
5485       int unsignedp = (DECL_UNSIGNED (TREE_OPERAND (op, 1))
5486                        || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op, 1))));
5487       type = lang_hooks.types.type_for_size (innerprec, unsignedp);
5488
5489       /* We can get this structure field in the narrowest type it fits in.
5490          If FOR_TYPE is 0, do this only for a field that matches the
5491          narrower type exactly and is aligned for it
5492          The resulting extension to its nominal type (a fullword type)
5493          must fit the same conditions as for other extensions.  */
5494
5495       if (type != 0
5496           && INT_CST_LT_UNSIGNED (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (op)))
5497           && (for_type || ! DECL_BIT_FIELD (TREE_OPERAND (op, 1)))
5498           && (! uns || final_prec <= innerprec || unsignedp))
5499         {
5500           win = build3 (COMPONENT_REF, type, TREE_OPERAND (op, 0),
5501                         TREE_OPERAND (op, 1), NULL_TREE);
5502           TREE_SIDE_EFFECTS (win) = TREE_SIDE_EFFECTS (op);
5503           TREE_THIS_VOLATILE (win) = TREE_THIS_VOLATILE (op);
5504         }
5505     }
5506
5507   return win;
5508 }
5509 \f
5510 /* Return OP or a simpler expression for a narrower value
5511    which can be sign-extended or zero-extended to give back OP.
5512    Store in *UNSIGNEDP_PTR either 1 if the value should be zero-extended
5513    or 0 if the value should be sign-extended.  */
5514
5515 tree
5516 get_narrower (tree op, int *unsignedp_ptr)
5517 {
5518   int uns = 0;
5519   int first = 1;
5520   tree win = op;
5521   bool integral_p = INTEGRAL_TYPE_P (TREE_TYPE (op));
5522
5523   while (TREE_CODE (op) == NOP_EXPR)
5524     {
5525       int bitschange
5526         = (TYPE_PRECISION (TREE_TYPE (op))
5527            - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0))));
5528
5529       /* Truncations are many-one so cannot be removed.  */
5530       if (bitschange < 0)
5531         break;
5532
5533       /* See what's inside this conversion.  If we decide to strip it,
5534          we will set WIN.  */
5535
5536       if (bitschange > 0)
5537         {
5538           op = TREE_OPERAND (op, 0);
5539           /* An extension: the outermost one can be stripped,
5540              but remember whether it is zero or sign extension.  */
5541           if (first)
5542             uns = TYPE_UNSIGNED (TREE_TYPE (op));
5543           /* Otherwise, if a sign extension has been stripped,
5544              only sign extensions can now be stripped;
5545              if a zero extension has been stripped, only zero-extensions.  */
5546           else if (uns != TYPE_UNSIGNED (TREE_TYPE (op)))
5547             break;
5548           first = 0;
5549         }
5550       else /* bitschange == 0 */
5551         {
5552           /* A change in nominal type can always be stripped, but we must
5553              preserve the unsignedness.  */
5554           if (first)
5555             uns = TYPE_UNSIGNED (TREE_TYPE (op));
5556           first = 0;
5557           op = TREE_OPERAND (op, 0);
5558           /* Keep trying to narrow, but don't assign op to win if it
5559              would turn an integral type into something else.  */
5560           if (INTEGRAL_TYPE_P (TREE_TYPE (op)) != integral_p)
5561             continue;
5562         }
5563
5564       win = op;
5565     }
5566
5567   if (TREE_CODE (op) == COMPONENT_REF
5568       /* Since type_for_size always gives an integer type.  */
5569       && TREE_CODE (TREE_TYPE (op)) != REAL_TYPE
5570       /* Ensure field is laid out already.  */
5571       && DECL_SIZE (TREE_OPERAND (op, 1)) != 0
5572       && host_integerp (DECL_SIZE (TREE_OPERAND (op, 1)), 1))
5573     {
5574       unsigned HOST_WIDE_INT innerprec
5575         = tree_low_cst (DECL_SIZE (TREE_OPERAND (op, 1)), 1);
5576       int unsignedp = (DECL_UNSIGNED (TREE_OPERAND (op, 1))
5577                        || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op, 1))));
5578       tree type = lang_hooks.types.type_for_size (innerprec, unsignedp);
5579
5580       /* We can get this structure field in a narrower type that fits it,
5581          but the resulting extension to its nominal type (a fullword type)
5582          must satisfy the same conditions as for other extensions.
5583
5584          Do this only for fields that are aligned (not bit-fields),
5585          because when bit-field insns will be used there is no
5586          advantage in doing this.  */
5587
5588       if (innerprec < TYPE_PRECISION (TREE_TYPE (op))
5589           && ! DECL_BIT_FIELD (TREE_OPERAND (op, 1))
5590           && (first || uns == DECL_UNSIGNED (TREE_OPERAND (op, 1)))
5591           && type != 0)
5592         {
5593           if (first)
5594             uns = DECL_UNSIGNED (TREE_OPERAND (op, 1));
5595           win = build3 (COMPONENT_REF, type, TREE_OPERAND (op, 0),
5596                         TREE_OPERAND (op, 1), NULL_TREE);
5597           TREE_SIDE_EFFECTS (win) = TREE_SIDE_EFFECTS (op);
5598           TREE_THIS_VOLATILE (win) = TREE_THIS_VOLATILE (op);
5599         }
5600     }
5601   *unsignedp_ptr = uns;
5602   return win;
5603 }
5604 \f
5605 /* Nonzero if integer constant C has a value that is permissible
5606    for type TYPE (an INTEGER_TYPE).  */
5607
5608 int
5609 int_fits_type_p (tree c, tree type)
5610 {
5611   tree type_low_bound = TYPE_MIN_VALUE (type);
5612   tree type_high_bound = TYPE_MAX_VALUE (type);
5613   bool ok_for_low_bound, ok_for_high_bound;
5614   tree tmp;
5615
5616   /* If at least one bound of the type is a constant integer, we can check
5617      ourselves and maybe make a decision. If no such decision is possible, but
5618      this type is a subtype, try checking against that.  Otherwise, use
5619      force_fit_type, which checks against the precision.
5620
5621      Compute the status for each possibly constant bound, and return if we see
5622      one does not match. Use ok_for_xxx_bound for this purpose, assigning -1
5623      for "unknown if constant fits", 0 for "constant known *not* to fit" and 1
5624      for "constant known to fit".  */
5625
5626   /* Check if C >= type_low_bound.  */
5627   if (type_low_bound && TREE_CODE (type_low_bound) == INTEGER_CST)
5628     {
5629       if (tree_int_cst_lt (c, type_low_bound))
5630         return 0;
5631       ok_for_low_bound = true;
5632     }
5633   else
5634     ok_for_low_bound = false;
5635
5636   /* Check if c <= type_high_bound.  */
5637   if (type_high_bound && TREE_CODE (type_high_bound) == INTEGER_CST)
5638     {
5639       if (tree_int_cst_lt (type_high_bound, c))
5640         return 0;
5641       ok_for_high_bound = true;
5642     }
5643   else
5644     ok_for_high_bound = false;
5645
5646   /* If the constant fits both bounds, the result is known.  */
5647   if (ok_for_low_bound && ok_for_high_bound)
5648     return 1;
5649
5650   /* Perform some generic filtering which may allow making a decision
5651      even if the bounds are not constant.  First, negative integers
5652      never fit in unsigned types, */
5653   if (TYPE_UNSIGNED (type) && tree_int_cst_sgn (c) < 0)
5654     return 0;
5655
5656   /* Second, narrower types always fit in wider ones.  */
5657   if (TYPE_PRECISION (type) > TYPE_PRECISION (TREE_TYPE (c)))
5658     return 1;
5659
5660   /* Third, unsigned integers with top bit set never fit signed types.  */
5661   if (! TYPE_UNSIGNED (type)
5662       && TYPE_UNSIGNED (TREE_TYPE (c))
5663       && tree_int_cst_msb (c))
5664     return 0;
5665
5666   /* If we haven't been able to decide at this point, there nothing more we
5667      can check ourselves here.  Look at the base type if we have one and it
5668      has the same precision.  */
5669   if (TREE_CODE (type) == INTEGER_TYPE
5670       && TREE_TYPE (type) != 0
5671       && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (type)))
5672     return int_fits_type_p (c, TREE_TYPE (type));
5673
5674   /* Or to force_fit_type, if nothing else.  */
5675   tmp = copy_node (c);
5676   TREE_TYPE (tmp) = type;
5677   tmp = force_fit_type (tmp, -1, false, false);
5678   return TREE_INT_CST_HIGH (tmp) == TREE_INT_CST_HIGH (c)
5679          && TREE_INT_CST_LOW (tmp) == TREE_INT_CST_LOW (c);
5680 }
5681
5682 /* Subprogram of following function.  Called by walk_tree.
5683
5684    Return *TP if it is an automatic variable or parameter of the
5685    function passed in as DATA.  */
5686
5687 static tree
5688 find_var_from_fn (tree *tp, int *walk_subtrees, void *data)
5689 {
5690   tree fn = (tree) data;
5691
5692   if (TYPE_P (*tp))
5693     *walk_subtrees = 0;
5694
5695   else if (DECL_P (*tp)
5696            && lang_hooks.tree_inlining.auto_var_in_fn_p (*tp, fn))
5697     return *tp;
5698
5699   return NULL_TREE;
5700 }
5701
5702 /* Returns true if T is, contains, or refers to a type with variable
5703    size.  For METHOD_TYPEs and FUNCTION_TYPEs we exclude the
5704    arguments, but not the return type.  If FN is nonzero, only return
5705    true if a modifier of the type or position of FN is a variable or
5706    parameter inside FN.
5707
5708    This concept is more general than that of C99 'variably modified types':
5709    in C99, a struct type is never variably modified because a VLA may not
5710    appear as a structure member.  However, in GNU C code like:
5711
5712      struct S { int i[f()]; };
5713
5714    is valid, and other languages may define similar constructs.  */
5715
5716 bool
5717 variably_modified_type_p (tree type, tree fn)
5718 {
5719   tree t;
5720
5721 /* Test if T is either variable (if FN is zero) or an expression containing
5722    a variable in FN.  */
5723 #define RETURN_TRUE_IF_VAR(T)                                           \
5724   do { tree _t = (T);                                                   \
5725     if (_t && _t != error_mark_node && TREE_CODE (_t) != INTEGER_CST    \
5726         && (!fn || walk_tree (&_t, find_var_from_fn, fn, NULL)))        \
5727       return true;  } while (0)
5728
5729   if (type == error_mark_node)
5730     return false;
5731
5732   /* If TYPE itself has variable size, it is variably modified.  */
5733   RETURN_TRUE_IF_VAR (TYPE_SIZE (type));
5734   RETURN_TRUE_IF_VAR (TYPE_SIZE_UNIT (type));
5735
5736   switch (TREE_CODE (type))
5737     {
5738     case POINTER_TYPE:
5739     case REFERENCE_TYPE:
5740     case VECTOR_TYPE:
5741       if (variably_modified_type_p (TREE_TYPE (type), fn))
5742         return true;
5743       break;
5744
5745     case FUNCTION_TYPE:
5746     case METHOD_TYPE:
5747       /* If TYPE is a function type, it is variably modified if the
5748          return type is variably modified.  */
5749       if (variably_modified_type_p (TREE_TYPE (type), fn))
5750           return true;
5751       break;
5752
5753     case INTEGER_TYPE:
5754     case REAL_TYPE:
5755     case ENUMERAL_TYPE:
5756     case BOOLEAN_TYPE:
5757       /* Scalar types are variably modified if their end points
5758          aren't constant.  */
5759       RETURN_TRUE_IF_VAR (TYPE_MIN_VALUE (type));
5760       RETURN_TRUE_IF_VAR (TYPE_MAX_VALUE (type));
5761       break;
5762
5763     case RECORD_TYPE:
5764     case UNION_TYPE:
5765     case QUAL_UNION_TYPE:
5766       /* We can't see if any of the fields are variably-modified by the
5767          definition we normally use, since that would produce infinite
5768          recursion via pointers.  */
5769       /* This is variably modified if some field's type is.  */
5770       for (t = TYPE_FIELDS (type); t; t = TREE_CHAIN (t))
5771         if (TREE_CODE (t) == FIELD_DECL)
5772           {
5773             RETURN_TRUE_IF_VAR (DECL_FIELD_OFFSET (t));
5774             RETURN_TRUE_IF_VAR (DECL_SIZE (t));
5775             RETURN_TRUE_IF_VAR (DECL_SIZE_UNIT (t));
5776
5777             if (TREE_CODE (type) == QUAL_UNION_TYPE)
5778               RETURN_TRUE_IF_VAR (DECL_QUALIFIER (t));
5779           }
5780         break;
5781
5782     case ARRAY_TYPE:
5783       /* Do not call ourselves to avoid infinite recursion.  This is
5784          variably modified if the element type is.  */
5785       RETURN_TRUE_IF_VAR (TYPE_SIZE (TREE_TYPE (type)));
5786       RETURN_TRUE_IF_VAR (TYPE_SIZE_UNIT (TREE_TYPE (type)));
5787       break;
5788
5789     default:
5790       break;
5791     }
5792
5793   /* The current language may have other cases to check, but in general,
5794      all other types are not variably modified.  */
5795   return lang_hooks.tree_inlining.var_mod_type_p (type, fn);
5796
5797 #undef RETURN_TRUE_IF_VAR
5798 }
5799
5800 /* Given a DECL or TYPE, return the scope in which it was declared, or
5801    NULL_TREE if there is no containing scope.  */
5802
5803 tree
5804 get_containing_scope (tree t)
5805 {
5806   return (TYPE_P (t) ? TYPE_CONTEXT (t) : DECL_CONTEXT (t));
5807 }
5808
5809 /* Return the innermost context enclosing DECL that is
5810    a FUNCTION_DECL, or zero if none.  */
5811
5812 tree
5813 decl_function_context (tree decl)
5814 {
5815   tree context;
5816
5817   if (TREE_CODE (decl) == ERROR_MARK)
5818     return 0;
5819
5820   /* C++ virtual functions use DECL_CONTEXT for the class of the vtable
5821      where we look up the function at runtime.  Such functions always take
5822      a first argument of type 'pointer to real context'.
5823
5824      C++ should really be fixed to use DECL_CONTEXT for the real context,
5825      and use something else for the "virtual context".  */
5826   else if (TREE_CODE (decl) == FUNCTION_DECL && DECL_VINDEX (decl))
5827     context
5828       = TYPE_MAIN_VARIANT
5829         (TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (decl)))));
5830   else
5831     context = DECL_CONTEXT (decl);
5832
5833   while (context && TREE_CODE (context) != FUNCTION_DECL)
5834     {
5835       if (TREE_CODE (context) == BLOCK)
5836         context = BLOCK_SUPERCONTEXT (context);
5837       else
5838         context = get_containing_scope (context);
5839     }
5840
5841   return context;
5842 }
5843
5844 /* Return the innermost context enclosing DECL that is
5845    a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE, or zero if none.
5846    TYPE_DECLs and FUNCTION_DECLs are transparent to this function.  */
5847
5848 tree
5849 decl_type_context (tree decl)
5850 {
5851   tree context = DECL_CONTEXT (decl);
5852
5853   while (context)
5854     switch (TREE_CODE (context))
5855       {
5856       case NAMESPACE_DECL:
5857       case TRANSLATION_UNIT_DECL:
5858         return NULL_TREE;
5859
5860       case RECORD_TYPE:
5861       case UNION_TYPE:
5862       case QUAL_UNION_TYPE:
5863         return context;
5864
5865       case TYPE_DECL:
5866       case FUNCTION_DECL:
5867         context = DECL_CONTEXT (context);
5868         break;
5869
5870       case BLOCK:
5871         context = BLOCK_SUPERCONTEXT (context);
5872         break;
5873
5874       default:
5875         gcc_unreachable ();
5876       }
5877
5878   return NULL_TREE;
5879 }
5880
5881 /* CALL is a CALL_EXPR.  Return the declaration for the function
5882    called, or NULL_TREE if the called function cannot be
5883    determined.  */
5884
5885 tree
5886 get_callee_fndecl (tree call)
5887 {
5888   tree addr;
5889
5890   if (call == error_mark_node)
5891     return call;
5892
5893   /* It's invalid to call this function with anything but a
5894      CALL_EXPR.  */
5895   gcc_assert (TREE_CODE (call) == CALL_EXPR);
5896
5897   /* The first operand to the CALL is the address of the function
5898      called.  */
5899   addr = TREE_OPERAND (call, 0);
5900
5901   STRIP_NOPS (addr);
5902
5903   /* If this is a readonly function pointer, extract its initial value.  */
5904   if (DECL_P (addr) && TREE_CODE (addr) != FUNCTION_DECL
5905       && TREE_READONLY (addr) && ! TREE_THIS_VOLATILE (addr)
5906       && DECL_INITIAL (addr))
5907     addr = DECL_INITIAL (addr);
5908
5909   /* If the address is just `&f' for some function `f', then we know
5910      that `f' is being called.  */
5911   if (TREE_CODE (addr) == ADDR_EXPR
5912       && TREE_CODE (TREE_OPERAND (addr, 0)) == FUNCTION_DECL)
5913     return TREE_OPERAND (addr, 0);
5914
5915   /* We couldn't figure out what was being called.  Maybe the front
5916      end has some idea.  */
5917   return lang_hooks.lang_get_callee_fndecl (call);
5918 }
5919
5920 /* Print debugging information about tree nodes generated during the compile,
5921    and any language-specific information.  */
5922
5923 void
5924 dump_tree_statistics (void)
5925 {
5926 #ifdef GATHER_STATISTICS
5927   int i;
5928   int total_nodes, total_bytes;
5929 #endif
5930
5931   fprintf (stderr, "\n??? tree nodes created\n\n");
5932 #ifdef GATHER_STATISTICS
5933   fprintf (stderr, "Kind                   Nodes      Bytes\n");
5934   fprintf (stderr, "---------------------------------------\n");
5935   total_nodes = total_bytes = 0;
5936   for (i = 0; i < (int) all_kinds; i++)
5937     {
5938       fprintf (stderr, "%-20s %7d %10d\n", tree_node_kind_names[i],
5939                tree_node_counts[i], tree_node_sizes[i]);
5940       total_nodes += tree_node_counts[i];
5941       total_bytes += tree_node_sizes[i];
5942     }
5943   fprintf (stderr, "---------------------------------------\n");
5944   fprintf (stderr, "%-20s %7d %10d\n", "Total", total_nodes, total_bytes);
5945   fprintf (stderr, "---------------------------------------\n");
5946   ssanames_print_statistics ();
5947   phinodes_print_statistics ();
5948 #else
5949   fprintf (stderr, "(No per-node statistics)\n");
5950 #endif
5951   print_type_hash_statistics ();
5952   print_debug_expr_statistics ();
5953   print_value_expr_statistics ();
5954   print_restrict_base_statistics ();
5955   lang_hooks.print_statistics ();
5956 }
5957 \f
5958 #define FILE_FUNCTION_FORMAT "_GLOBAL__%s_%s"
5959
5960 /* Generate a crc32 of a string.  */
5961
5962 unsigned
5963 crc32_string (unsigned chksum, const char *string)
5964 {
5965   do
5966     {
5967       unsigned value = *string << 24;
5968       unsigned ix;
5969
5970       for (ix = 8; ix--; value <<= 1)
5971         {
5972           unsigned feedback;
5973
5974           feedback = (value ^ chksum) & 0x80000000 ? 0x04c11db7 : 0;
5975           chksum <<= 1;
5976           chksum ^= feedback;
5977         }
5978     }
5979   while (*string++);
5980   return chksum;
5981 }
5982
5983 /* P is a string that will be used in a symbol.  Mask out any characters
5984    that are not valid in that context.  */
5985
5986 void
5987 clean_symbol_name (char *p)
5988 {
5989   for (; *p; p++)
5990     if (! (ISALNUM (*p)
5991 #ifndef NO_DOLLAR_IN_LABEL      /* this for `$'; unlikely, but... -- kr */
5992             || *p == '$'
5993 #endif
5994 #ifndef NO_DOT_IN_LABEL         /* this for `.'; unlikely, but...  */
5995             || *p == '.'
5996 #endif
5997            ))
5998       *p = '_';
5999 }
6000
6001 /* Generate a name for a function unique to this translation unit.
6002    TYPE is some string to identify the purpose of this function to the
6003    linker or collect2.  */
6004
6005 tree
6006 get_file_function_name_long (const char *type)
6007 {
6008   char *buf;
6009   const char *p;
6010   char *q;
6011
6012   if (first_global_object_name)
6013     {
6014       p = first_global_object_name;
6015
6016       /* For type 'F', the generated name must be unique not only to this
6017          translation unit but also to any given link.  Since global names
6018          can be overloaded, we concatenate the first global object name
6019          with a string derived from the file name of this object.  */
6020       if (!strcmp (type, "F"))
6021         {
6022           const char *file = main_input_filename;
6023
6024           if (! file)
6025             file = input_filename;
6026
6027           q = alloca (strlen (p) + 10);
6028           sprintf (q, "%s_%08X", p, crc32_string (0, file));
6029
6030           p = q;
6031         }
6032     }
6033   else
6034     {
6035       /* We don't have anything that we know to be unique to this translation
6036          unit, so use what we do have and throw in some randomness.  */
6037       unsigned len;
6038       const char *name = weak_global_object_name;
6039       const char *file = main_input_filename;
6040
6041       if (! name)
6042         name = "";
6043       if (! file)
6044         file = input_filename;
6045
6046       len = strlen (file);
6047       q = alloca (9 * 2 + len + 1);
6048       memcpy (q, file, len + 1);
6049       clean_symbol_name (q);
6050
6051       sprintf (q + len, "_%08X_%08X", crc32_string (0, name),
6052                crc32_string (0, flag_random_seed));
6053
6054       p = q;
6055     }
6056
6057   buf = alloca (sizeof (FILE_FUNCTION_FORMAT) + strlen (p) + strlen (type));
6058
6059   /* Set up the name of the file-level functions we may need.
6060      Use a global object (which is already required to be unique over
6061      the program) rather than the file name (which imposes extra
6062      constraints).  */
6063   sprintf (buf, FILE_FUNCTION_FORMAT, type, p);
6064
6065   return get_identifier (buf);
6066 }
6067
6068 /* If KIND=='I', return a suitable global initializer (constructor) name.
6069    If KIND=='D', return a suitable global clean-up (destructor) name.  */
6070
6071 tree
6072 get_file_function_name (int kind)
6073 {
6074   char p[2];
6075
6076   p[0] = kind;
6077   p[1] = 0;
6078
6079   return get_file_function_name_long (p);
6080 }
6081 \f
6082 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
6083
6084 /* Complain that the tree code of NODE does not match the expected 0
6085    terminated list of trailing codes. The trailing code list can be
6086    empty, for a more vague error message.  FILE, LINE, and FUNCTION
6087    are of the caller.  */
6088
6089 void
6090 tree_check_failed (const tree node, const char *file,
6091                    int line, const char *function, ...)
6092 {
6093   va_list args;
6094   char *buffer;
6095   unsigned length = 0;
6096   int code;
6097
6098   va_start (args, function);
6099   while ((code = va_arg (args, int)))
6100     length += 4 + strlen (tree_code_name[code]);
6101   va_end (args);
6102   if (length)
6103     {
6104       va_start (args, function);
6105       length += strlen ("expected ");
6106       buffer = alloca (length);
6107       length = 0;
6108       while ((code = va_arg (args, int)))
6109         {
6110           const char *prefix = length ? " or " : "expected ";
6111
6112           strcpy (buffer + length, prefix);
6113           length += strlen (prefix);
6114           strcpy (buffer + length, tree_code_name[code]);
6115           length += strlen (tree_code_name[code]);
6116         }
6117       va_end (args);
6118     }
6119   else
6120     buffer = (char *)"unexpected node";
6121
6122   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6123                   buffer, tree_code_name[TREE_CODE (node)],
6124                   function, trim_filename (file), line);
6125 }
6126
6127 /* Complain that the tree code of NODE does match the expected 0
6128    terminated list of trailing codes. FILE, LINE, and FUNCTION are of
6129    the caller.  */
6130
6131 void
6132 tree_not_check_failed (const tree node, const char *file,
6133                        int line, const char *function, ...)
6134 {
6135   va_list args;
6136   char *buffer;
6137   unsigned length = 0;
6138   int code;
6139
6140   va_start (args, function);
6141   while ((code = va_arg (args, int)))
6142     length += 4 + strlen (tree_code_name[code]);
6143   va_end (args);
6144   va_start (args, function);
6145   buffer = alloca (length);
6146   length = 0;
6147   while ((code = va_arg (args, int)))
6148     {
6149       if (length)
6150         {
6151           strcpy (buffer + length, " or ");
6152           length += 4;
6153         }
6154       strcpy (buffer + length, tree_code_name[code]);
6155       length += strlen (tree_code_name[code]);
6156     }
6157   va_end (args);
6158
6159   internal_error ("tree check: expected none of %s, have %s in %s, at %s:%d",
6160                   buffer, tree_code_name[TREE_CODE (node)],
6161                   function, trim_filename (file), line);
6162 }
6163
6164 /* Similar to tree_check_failed, except that we check for a class of tree
6165    code, given in CL.  */
6166
6167 void
6168 tree_class_check_failed (const tree node, const enum tree_code_class cl,
6169                          const char *file, int line, const char *function)
6170 {
6171   internal_error
6172     ("tree check: expected class %qs, have %qs (%s) in %s, at %s:%d",
6173      TREE_CODE_CLASS_STRING (cl),
6174      TREE_CODE_CLASS_STRING (TREE_CODE_CLASS (TREE_CODE (node))),
6175      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6176 }
6177
6178 /* Similar to tree_check_failed, except that instead of specifying a
6179    dozen codes, use the knowledge that they're all sequential.  */
6180
6181 void
6182 tree_range_check_failed (const tree node, const char *file, int line,
6183                          const char *function, enum tree_code c1,
6184                          enum tree_code c2)
6185 {
6186   char *buffer;
6187   unsigned length = 0;
6188   enum tree_code c;
6189
6190   for (c = c1; c <= c2; ++c)
6191     length += 4 + strlen (tree_code_name[c]);
6192
6193   length += strlen ("expected ");
6194   buffer = alloca (length);
6195   length = 0;
6196
6197   for (c = c1; c <= c2; ++c)
6198     {
6199       const char *prefix = length ? " or " : "expected ";
6200
6201       strcpy (buffer + length, prefix);
6202       length += strlen (prefix);
6203       strcpy (buffer + length, tree_code_name[c]);
6204       length += strlen (tree_code_name[c]);
6205     }
6206
6207   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6208                   buffer, tree_code_name[TREE_CODE (node)],
6209                   function, trim_filename (file), line);
6210 }
6211
6212
6213 /* Similar to tree_check_failed, except that we check that a tree does
6214    not have the specified code, given in CL.  */
6215
6216 void
6217 tree_not_class_check_failed (const tree node, const enum tree_code_class cl,
6218                              const char *file, int line, const char *function)
6219 {
6220   internal_error
6221     ("tree check: did not expect class %qs, have %qs (%s) in %s, at %s:%d",
6222      TREE_CODE_CLASS_STRING (cl),
6223      TREE_CODE_CLASS_STRING (TREE_CODE_CLASS (TREE_CODE (node))),
6224      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6225 }
6226
6227
6228 /* Similar to tree_check_failed but applied to OMP_CLAUSE codes.  */
6229
6230 void
6231 omp_clause_check_failed (const tree node, const char *file, int line,
6232                          const char *function, enum omp_clause_code code)
6233 {
6234   internal_error ("tree check: expected omp_clause %s, have %s in %s, at %s:%d",
6235                   omp_clause_code_name[code], tree_code_name[TREE_CODE (node)],
6236                   function, trim_filename (file), line);
6237 }
6238
6239
6240 /* Similar to tree_range_check_failed but applied to OMP_CLAUSE codes.  */
6241
6242 void
6243 omp_clause_range_check_failed (const tree node, const char *file, int line,
6244                                const char *function, enum omp_clause_code c1,
6245                                enum omp_clause_code c2)
6246 {
6247   char *buffer;
6248   unsigned length = 0;
6249   enum omp_clause_code c;
6250
6251   for (c = c1; c <= c2; ++c)
6252     length += 4 + strlen (omp_clause_code_name[c]);
6253
6254   length += strlen ("expected ");
6255   buffer = alloca (length);
6256   length = 0;
6257
6258   for (c = c1; c <= c2; ++c)
6259     {
6260       const char *prefix = length ? " or " : "expected ";
6261
6262       strcpy (buffer + length, prefix);
6263       length += strlen (prefix);
6264       strcpy (buffer + length, omp_clause_code_name[c]);
6265       length += strlen (omp_clause_code_name[c]);
6266     }
6267
6268   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6269                   buffer, omp_clause_code_name[TREE_CODE (node)],
6270                   function, trim_filename (file), line);
6271 }
6272
6273
6274 #undef DEFTREESTRUCT
6275 #define DEFTREESTRUCT(VAL, NAME) NAME,
6276
6277 static const char *ts_enum_names[] = {
6278 #include "treestruct.def"
6279 };
6280 #undef DEFTREESTRUCT
6281
6282 #define TS_ENUM_NAME(EN) (ts_enum_names[(EN)])
6283
6284 /* Similar to tree_class_check_failed, except that we check for
6285    whether CODE contains the tree structure identified by EN.  */
6286
6287 void
6288 tree_contains_struct_check_failed (const tree node,
6289                                    const enum tree_node_structure_enum en,
6290                                    const char *file, int line,
6291                                    const char *function)
6292 {
6293   internal_error
6294     ("tree check: expected tree that contains %qs structure, have %qs  in %s, at %s:%d",
6295      TS_ENUM_NAME(en),
6296      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6297 }
6298
6299
6300 /* Similar to above, except that the check is for the bounds of a TREE_VEC's
6301    (dynamically sized) vector.  */
6302
6303 void
6304 tree_vec_elt_check_failed (int idx, int len, const char *file, int line,
6305                            const char *function)
6306 {
6307   internal_error
6308     ("tree check: accessed elt %d of tree_vec with %d elts in %s, at %s:%d",
6309      idx + 1, len, function, trim_filename (file), line);
6310 }
6311
6312 /* Similar to above, except that the check is for the bounds of a PHI_NODE's
6313    (dynamically sized) vector.  */
6314
6315 void
6316 phi_node_elt_check_failed (int idx, int len, const char *file, int line,
6317                             const char *function)
6318 {
6319   internal_error
6320     ("tree check: accessed elt %d of phi_node with %d elts in %s, at %s:%d",
6321      idx + 1, len, function, trim_filename (file), line);
6322 }
6323
6324 /* Similar to above, except that the check is for the bounds of the operand
6325    vector of an expression node.  */
6326
6327 void
6328 tree_operand_check_failed (int idx, enum tree_code code, const char *file,
6329                            int line, const char *function)
6330 {
6331   internal_error
6332     ("tree check: accessed operand %d of %s with %d operands in %s, at %s:%d",
6333      idx + 1, tree_code_name[code], TREE_CODE_LENGTH (code),
6334      function, trim_filename (file), line);
6335 }
6336
6337 /* Similar to above, except that the check is for the number of
6338    operands of an OMP_CLAUSE node.  */
6339
6340 void
6341 omp_clause_operand_check_failed (int idx, tree t, const char *file,
6342                                  int line, const char *function)
6343 {
6344   internal_error
6345     ("tree check: accessed operand %d of omp_clause %s with %d operands "
6346      "in %s, at %s:%d", idx + 1, omp_clause_code_name[OMP_CLAUSE_CODE (t)],
6347      omp_clause_num_ops [OMP_CLAUSE_CODE (t)], function,
6348      trim_filename (file), line);
6349 }
6350 #endif /* ENABLE_TREE_CHECKING */
6351 \f
6352 /* Create a new vector type node holding SUBPARTS units of type INNERTYPE,
6353    and mapped to the machine mode MODE.  Initialize its fields and build
6354    the information necessary for debugging output.  */
6355
6356 static tree
6357 make_vector_type (tree innertype, int nunits, enum machine_mode mode)
6358 {
6359   tree t = make_node (VECTOR_TYPE);
6360
6361   TREE_TYPE (t) = TYPE_MAIN_VARIANT (innertype);
6362   SET_TYPE_VECTOR_SUBPARTS (t, nunits);
6363   TYPE_MODE (t) = mode;
6364   TYPE_READONLY (t) = TYPE_READONLY (innertype);
6365   TYPE_VOLATILE (t) = TYPE_VOLATILE (innertype);
6366
6367   layout_type (t);
6368
6369   {
6370     tree index = build_int_cst (NULL_TREE, nunits - 1);
6371     tree array = build_array_type (innertype, build_index_type (index));
6372     tree rt = make_node (RECORD_TYPE);
6373
6374     TYPE_FIELDS (rt) = build_decl (FIELD_DECL, get_identifier ("f"), array);
6375     DECL_CONTEXT (TYPE_FIELDS (rt)) = rt;
6376     layout_type (rt);
6377     TYPE_DEBUG_REPRESENTATION_TYPE (t) = rt;
6378     /* In dwarfout.c, type lookup uses TYPE_UID numbers.  We want to output
6379        the representation type, and we want to find that die when looking up
6380        the vector type.  This is most easily achieved by making the TYPE_UID
6381        numbers equal.  */
6382     TYPE_UID (rt) = TYPE_UID (t);
6383   }
6384
6385   /* Build our main variant, based on the main variant of the inner type.  */
6386   if (TYPE_MAIN_VARIANT (innertype) != innertype)
6387     {
6388       tree innertype_main_variant = TYPE_MAIN_VARIANT (innertype);
6389       unsigned int hash = TYPE_HASH (innertype_main_variant);
6390       TYPE_MAIN_VARIANT (t)
6391         = type_hash_canon (hash, make_vector_type (innertype_main_variant,
6392                                                    nunits, mode));
6393     }
6394
6395   return t;
6396 }
6397
6398 static tree
6399 make_or_reuse_type (unsigned size, int unsignedp)
6400 {
6401   if (size == INT_TYPE_SIZE)
6402     return unsignedp ? unsigned_type_node : integer_type_node;
6403   if (size == CHAR_TYPE_SIZE)
6404     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
6405   if (size == SHORT_TYPE_SIZE)
6406     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
6407   if (size == LONG_TYPE_SIZE)
6408     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
6409   if (size == LONG_LONG_TYPE_SIZE)
6410     return (unsignedp ? long_long_unsigned_type_node
6411             : long_long_integer_type_node);
6412
6413   if (unsignedp)
6414     return make_unsigned_type (size);
6415   else
6416     return make_signed_type (size);
6417 }
6418
6419 /* Create nodes for all integer types (and error_mark_node) using the sizes
6420    of C datatypes.  The caller should call set_sizetype soon after calling
6421    this function to select one of the types as sizetype.  */
6422
6423 void
6424 build_common_tree_nodes (bool signed_char, bool signed_sizetype)
6425 {
6426   error_mark_node = make_node (ERROR_MARK);
6427   TREE_TYPE (error_mark_node) = error_mark_node;
6428
6429   initialize_sizetypes (signed_sizetype);
6430
6431   /* Define both `signed char' and `unsigned char'.  */
6432   signed_char_type_node = make_signed_type (CHAR_TYPE_SIZE);
6433   TYPE_STRING_FLAG (signed_char_type_node) = 1;
6434   unsigned_char_type_node = make_unsigned_type (CHAR_TYPE_SIZE);
6435   TYPE_STRING_FLAG (unsigned_char_type_node) = 1;
6436
6437   /* Define `char', which is like either `signed char' or `unsigned char'
6438      but not the same as either.  */
6439   char_type_node
6440     = (signed_char
6441        ? make_signed_type (CHAR_TYPE_SIZE)
6442        : make_unsigned_type (CHAR_TYPE_SIZE));
6443   TYPE_STRING_FLAG (char_type_node) = 1;
6444
6445   short_integer_type_node = make_signed_type (SHORT_TYPE_SIZE);
6446   short_unsigned_type_node = make_unsigned_type (SHORT_TYPE_SIZE);
6447   integer_type_node = make_signed_type (INT_TYPE_SIZE);
6448   unsigned_type_node = make_unsigned_type (INT_TYPE_SIZE);
6449   long_integer_type_node = make_signed_type (LONG_TYPE_SIZE);
6450   long_unsigned_type_node = make_unsigned_type (LONG_TYPE_SIZE);
6451   long_long_integer_type_node = make_signed_type (LONG_LONG_TYPE_SIZE);
6452   long_long_unsigned_type_node = make_unsigned_type (LONG_LONG_TYPE_SIZE);
6453
6454   /* Define a boolean type.  This type only represents boolean values but
6455      may be larger than char depending on the value of BOOL_TYPE_SIZE.
6456      Front ends which want to override this size (i.e. Java) can redefine
6457      boolean_type_node before calling build_common_tree_nodes_2.  */
6458   boolean_type_node = make_unsigned_type (BOOL_TYPE_SIZE);
6459   TREE_SET_CODE (boolean_type_node, BOOLEAN_TYPE);
6460   TYPE_MAX_VALUE (boolean_type_node) = build_int_cst (boolean_type_node, 1);
6461   TYPE_PRECISION (boolean_type_node) = 1;
6462
6463   /* Fill in the rest of the sized types.  Reuse existing type nodes
6464      when possible.  */
6465   intQI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (QImode), 0);
6466   intHI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (HImode), 0);
6467   intSI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (SImode), 0);
6468   intDI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (DImode), 0);
6469   intTI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (TImode), 0);
6470
6471   unsigned_intQI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (QImode), 1);
6472   unsigned_intHI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (HImode), 1);
6473   unsigned_intSI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (SImode), 1);
6474   unsigned_intDI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (DImode), 1);
6475   unsigned_intTI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (TImode), 1);
6476
6477   access_public_node = get_identifier ("public");
6478   access_protected_node = get_identifier ("protected");
6479   access_private_node = get_identifier ("private");
6480 }
6481
6482 /* Call this function after calling build_common_tree_nodes and set_sizetype.
6483    It will create several other common tree nodes.  */
6484
6485 void
6486 build_common_tree_nodes_2 (int short_double)
6487 {
6488   /* Define these next since types below may used them.  */
6489   integer_zero_node = build_int_cst (NULL_TREE, 0);
6490   integer_one_node = build_int_cst (NULL_TREE, 1);
6491   integer_minus_one_node = build_int_cst (NULL_TREE, -1);
6492
6493   size_zero_node = size_int (0);
6494   size_one_node = size_int (1);
6495   bitsize_zero_node = bitsize_int (0);
6496   bitsize_one_node = bitsize_int (1);
6497   bitsize_unit_node = bitsize_int (BITS_PER_UNIT);
6498
6499   boolean_false_node = TYPE_MIN_VALUE (boolean_type_node);
6500   boolean_true_node = TYPE_MAX_VALUE (boolean_type_node);
6501
6502   void_type_node = make_node (VOID_TYPE);
6503   layout_type (void_type_node);
6504
6505   /* We are not going to have real types in C with less than byte alignment,
6506      so we might as well not have any types that claim to have it.  */
6507   TYPE_ALIGN (void_type_node) = BITS_PER_UNIT;
6508   TYPE_USER_ALIGN (void_type_node) = 0;
6509
6510   null_pointer_node = build_int_cst (build_pointer_type (void_type_node), 0);
6511   layout_type (TREE_TYPE (null_pointer_node));
6512
6513   ptr_type_node = build_pointer_type (void_type_node);
6514   const_ptr_type_node
6515     = build_pointer_type (build_type_variant (void_type_node, 1, 0));
6516   fileptr_type_node = ptr_type_node;
6517
6518   float_type_node = make_node (REAL_TYPE);
6519   TYPE_PRECISION (float_type_node) = FLOAT_TYPE_SIZE;
6520   layout_type (float_type_node);
6521
6522   double_type_node = make_node (REAL_TYPE);
6523   if (short_double)
6524     TYPE_PRECISION (double_type_node) = FLOAT_TYPE_SIZE;
6525   else
6526     TYPE_PRECISION (double_type_node) = DOUBLE_TYPE_SIZE;
6527   layout_type (double_type_node);
6528
6529   long_double_type_node = make_node (REAL_TYPE);
6530   TYPE_PRECISION (long_double_type_node) = LONG_DOUBLE_TYPE_SIZE;
6531   layout_type (long_double_type_node);
6532
6533   float_ptr_type_node = build_pointer_type (float_type_node);
6534   double_ptr_type_node = build_pointer_type (double_type_node);
6535   long_double_ptr_type_node = build_pointer_type (long_double_type_node);
6536   integer_ptr_type_node = build_pointer_type (integer_type_node);
6537
6538   /* Decimal float types. */
6539   dfloat32_type_node = make_node (REAL_TYPE);
6540   TYPE_PRECISION (dfloat32_type_node) = DECIMAL32_TYPE_SIZE;
6541   layout_type (dfloat32_type_node);
6542   TYPE_MODE (dfloat32_type_node) = SDmode;
6543   dfloat32_ptr_type_node = build_pointer_type (dfloat32_type_node);
6544
6545   dfloat64_type_node = make_node (REAL_TYPE);
6546   TYPE_PRECISION (dfloat64_type_node) = DECIMAL64_TYPE_SIZE;
6547   layout_type (dfloat64_type_node);
6548   TYPE_MODE (dfloat64_type_node) = DDmode;
6549   dfloat64_ptr_type_node = build_pointer_type (dfloat64_type_node);
6550
6551   dfloat128_type_node = make_node (REAL_TYPE);
6552   TYPE_PRECISION (dfloat128_type_node) = DECIMAL128_TYPE_SIZE;
6553   layout_type (dfloat128_type_node);
6554   TYPE_MODE (dfloat128_type_node) = TDmode;
6555   dfloat128_ptr_type_node = build_pointer_type (dfloat128_type_node);
6556
6557   complex_integer_type_node = make_node (COMPLEX_TYPE);
6558   TREE_TYPE (complex_integer_type_node) = integer_type_node;
6559   layout_type (complex_integer_type_node);
6560
6561   complex_float_type_node = make_node (COMPLEX_TYPE);
6562   TREE_TYPE (complex_float_type_node) = float_type_node;
6563   layout_type (complex_float_type_node);
6564
6565   complex_double_type_node = make_node (COMPLEX_TYPE);
6566   TREE_TYPE (complex_double_type_node) = double_type_node;
6567   layout_type (complex_double_type_node);
6568
6569   complex_long_double_type_node = make_node (COMPLEX_TYPE);
6570   TREE_TYPE (complex_long_double_type_node) = long_double_type_node;
6571   layout_type (complex_long_double_type_node);
6572
6573   {
6574     tree t = targetm.build_builtin_va_list ();
6575
6576     /* Many back-ends define record types without setting TYPE_NAME.
6577        If we copied the record type here, we'd keep the original
6578        record type without a name.  This breaks name mangling.  So,
6579        don't copy record types and let c_common_nodes_and_builtins()
6580        declare the type to be __builtin_va_list.  */
6581     if (TREE_CODE (t) != RECORD_TYPE)
6582       t = build_variant_type_copy (t);
6583
6584     va_list_type_node = t;
6585   }
6586 }
6587
6588 /* A subroutine of build_common_builtin_nodes.  Define a builtin function.  */
6589
6590 static void
6591 local_define_builtin (const char *name, tree type, enum built_in_function code,
6592                       const char *library_name, int ecf_flags)
6593 {
6594   tree decl;
6595
6596   decl = lang_hooks.builtin_function (name, type, code, BUILT_IN_NORMAL,
6597                                       library_name, NULL_TREE);
6598   if (ecf_flags & ECF_CONST)
6599     TREE_READONLY (decl) = 1;
6600   if (ecf_flags & ECF_PURE)
6601     DECL_IS_PURE (decl) = 1;
6602   if (ecf_flags & ECF_NORETURN)
6603     TREE_THIS_VOLATILE (decl) = 1;
6604   if (ecf_flags & ECF_NOTHROW)
6605     TREE_NOTHROW (decl) = 1;
6606   if (ecf_flags & ECF_MALLOC)
6607     DECL_IS_MALLOC (decl) = 1;
6608
6609   built_in_decls[code] = decl;
6610   implicit_built_in_decls[code] = decl;
6611 }
6612
6613 /* Call this function after instantiating all builtins that the language
6614    front end cares about.  This will build the rest of the builtins that
6615    are relied upon by the tree optimizers and the middle-end.  */
6616
6617 void
6618 build_common_builtin_nodes (void)
6619 {
6620   tree tmp, ftype;
6621
6622   if (built_in_decls[BUILT_IN_MEMCPY] == NULL
6623       || built_in_decls[BUILT_IN_MEMMOVE] == NULL)
6624     {
6625       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6626       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6627       tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6628       ftype = build_function_type (ptr_type_node, tmp);
6629
6630       if (built_in_decls[BUILT_IN_MEMCPY] == NULL)
6631         local_define_builtin ("__builtin_memcpy", ftype, BUILT_IN_MEMCPY,
6632                               "memcpy", ECF_NOTHROW);
6633       if (built_in_decls[BUILT_IN_MEMMOVE] == NULL)
6634         local_define_builtin ("__builtin_memmove", ftype, BUILT_IN_MEMMOVE,
6635                               "memmove", ECF_NOTHROW);
6636     }
6637
6638   if (built_in_decls[BUILT_IN_MEMCMP] == NULL)
6639     {
6640       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6641       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6642       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6643       ftype = build_function_type (integer_type_node, tmp);
6644       local_define_builtin ("__builtin_memcmp", ftype, BUILT_IN_MEMCMP,
6645                             "memcmp", ECF_PURE | ECF_NOTHROW);
6646     }
6647
6648   if (built_in_decls[BUILT_IN_MEMSET] == NULL)
6649     {
6650       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6651       tmp = tree_cons (NULL_TREE, integer_type_node, tmp);
6652       tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6653       ftype = build_function_type (ptr_type_node, tmp);
6654       local_define_builtin ("__builtin_memset", ftype, BUILT_IN_MEMSET,
6655                             "memset", ECF_NOTHROW);
6656     }
6657
6658   if (built_in_decls[BUILT_IN_ALLOCA] == NULL)
6659     {
6660       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6661       ftype = build_function_type (ptr_type_node, tmp);
6662       local_define_builtin ("__builtin_alloca", ftype, BUILT_IN_ALLOCA,
6663                             "alloca", ECF_NOTHROW | ECF_MALLOC);
6664     }
6665
6666   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6667   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6668   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6669   ftype = build_function_type (void_type_node, tmp);
6670   local_define_builtin ("__builtin_init_trampoline", ftype,
6671                         BUILT_IN_INIT_TRAMPOLINE,
6672                         "__builtin_init_trampoline", ECF_NOTHROW);
6673
6674   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6675   ftype = build_function_type (ptr_type_node, tmp);
6676   local_define_builtin ("__builtin_adjust_trampoline", ftype,
6677                         BUILT_IN_ADJUST_TRAMPOLINE,
6678                         "__builtin_adjust_trampoline",
6679                         ECF_CONST | ECF_NOTHROW);
6680
6681   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6682   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6683   ftype = build_function_type (void_type_node, tmp);
6684   local_define_builtin ("__builtin_nonlocal_goto", ftype,
6685                         BUILT_IN_NONLOCAL_GOTO,
6686                         "__builtin_nonlocal_goto",
6687                         ECF_NORETURN | ECF_NOTHROW);
6688
6689   ftype = build_function_type (ptr_type_node, void_list_node);
6690   local_define_builtin ("__builtin_stack_save", ftype, BUILT_IN_STACK_SAVE,
6691                         "__builtin_stack_save", ECF_NOTHROW);
6692
6693   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
6694   ftype = build_function_type (void_type_node, tmp);
6695   local_define_builtin ("__builtin_stack_restore", ftype,
6696                         BUILT_IN_STACK_RESTORE,
6697                         "__builtin_stack_restore", ECF_NOTHROW);
6698
6699   ftype = build_function_type (void_type_node, void_list_node);
6700   local_define_builtin ("__builtin_profile_func_enter", ftype,
6701                         BUILT_IN_PROFILE_FUNC_ENTER, "profile_func_enter", 0);
6702   local_define_builtin ("__builtin_profile_func_exit", ftype,
6703                         BUILT_IN_PROFILE_FUNC_EXIT, "profile_func_exit", 0);
6704
6705   /* Complex multiplication and division.  These are handled as builtins
6706      rather than optabs because emit_library_call_value doesn't support
6707      complex.  Further, we can do slightly better with folding these
6708      beasties if the real and complex parts of the arguments are separate.  */
6709   {
6710     enum machine_mode mode;
6711
6712     for (mode = MIN_MODE_COMPLEX_FLOAT; mode <= MAX_MODE_COMPLEX_FLOAT; ++mode)
6713       {
6714         char mode_name_buf[4], *q;
6715         const char *p;
6716         enum built_in_function mcode, dcode;
6717         tree type, inner_type;
6718
6719         type = lang_hooks.types.type_for_mode (mode, 0);
6720         if (type == NULL)
6721           continue;
6722         inner_type = TREE_TYPE (type);
6723
6724         tmp = tree_cons (NULL_TREE, inner_type, void_list_node);
6725         tmp = tree_cons (NULL_TREE, inner_type, tmp);
6726         tmp = tree_cons (NULL_TREE, inner_type, tmp);
6727         tmp = tree_cons (NULL_TREE, inner_type, tmp);
6728         ftype = build_function_type (type, tmp);
6729
6730         mcode = BUILT_IN_COMPLEX_MUL_MIN + mode - MIN_MODE_COMPLEX_FLOAT;
6731         dcode = BUILT_IN_COMPLEX_DIV_MIN + mode - MIN_MODE_COMPLEX_FLOAT;
6732
6733         for (p = GET_MODE_NAME (mode), q = mode_name_buf; *p; p++, q++)
6734           *q = TOLOWER (*p);
6735         *q = '\0';
6736
6737         built_in_names[mcode] = concat ("__mul", mode_name_buf, "3", NULL);
6738         local_define_builtin (built_in_names[mcode], ftype, mcode,
6739                               built_in_names[mcode], ECF_CONST | ECF_NOTHROW);
6740
6741         built_in_names[dcode] = concat ("__div", mode_name_buf, "3", NULL);
6742         local_define_builtin (built_in_names[dcode], ftype, dcode,
6743                               built_in_names[dcode], ECF_CONST | ECF_NOTHROW);
6744       }
6745   }
6746 }
6747
6748 /* HACK.  GROSS.  This is absolutely disgusting.  I wish there was a
6749    better way.
6750
6751    If we requested a pointer to a vector, build up the pointers that
6752    we stripped off while looking for the inner type.  Similarly for
6753    return values from functions.
6754
6755    The argument TYPE is the top of the chain, and BOTTOM is the
6756    new type which we will point to.  */
6757
6758 tree
6759 reconstruct_complex_type (tree type, tree bottom)
6760 {
6761   tree inner, outer;
6762
6763   if (POINTER_TYPE_P (type))
6764     {
6765       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6766       outer = build_pointer_type (inner);
6767     }
6768   else if (TREE_CODE (type) == ARRAY_TYPE)
6769     {
6770       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6771       outer = build_array_type (inner, TYPE_DOMAIN (type));
6772     }
6773   else if (TREE_CODE (type) == FUNCTION_TYPE)
6774     {
6775       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6776       outer = build_function_type (inner, TYPE_ARG_TYPES (type));
6777     }
6778   else if (TREE_CODE (type) == METHOD_TYPE)
6779     {
6780       tree argtypes;
6781       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
6782       /* The build_method_type_directly() routine prepends 'this' to argument list,
6783          so we must compensate by getting rid of it.  */
6784       argtypes = TYPE_ARG_TYPES (type);
6785       outer = build_method_type_directly (TYPE_METHOD_BASETYPE (type),
6786                                           inner,
6787                                           TYPE_ARG_TYPES (type));
6788       TYPE_ARG_TYPES (outer) = argtypes;
6789     }
6790   else
6791     return bottom;
6792
6793   TYPE_READONLY (outer) = TYPE_READONLY (type);
6794   TYPE_VOLATILE (outer) = TYPE_VOLATILE (type);
6795
6796   return outer;
6797 }
6798
6799 /* Returns a vector tree node given a mode (integer, vector, or BLKmode) and
6800    the inner type.  */
6801 tree
6802 build_vector_type_for_mode (tree innertype, enum machine_mode mode)
6803 {
6804   int nunits;
6805
6806   switch (GET_MODE_CLASS (mode))
6807     {
6808     case MODE_VECTOR_INT:
6809     case MODE_VECTOR_FLOAT:
6810       nunits = GET_MODE_NUNITS (mode);
6811       break;
6812
6813     case MODE_INT:
6814       /* Check that there are no leftover bits.  */
6815       gcc_assert (GET_MODE_BITSIZE (mode)
6816                   % TREE_INT_CST_LOW (TYPE_SIZE (innertype)) == 0);
6817
6818       nunits = GET_MODE_BITSIZE (mode)
6819                / TREE_INT_CST_LOW (TYPE_SIZE (innertype));
6820       break;
6821
6822     default:
6823       gcc_unreachable ();
6824     }
6825
6826   return make_vector_type (innertype, nunits, mode);
6827 }
6828
6829 /* Similarly, but takes the inner type and number of units, which must be
6830    a power of two.  */
6831
6832 tree
6833 build_vector_type (tree innertype, int nunits)
6834 {
6835   return make_vector_type (innertype, nunits, VOIDmode);
6836 }
6837
6838 /* Build RESX_EXPR with given REGION_NUMBER.  */
6839 tree
6840 build_resx (int region_number)
6841 {
6842   tree t;
6843   t = build1 (RESX_EXPR, void_type_node,
6844               build_int_cst (NULL_TREE, region_number));
6845   return t;
6846 }
6847
6848 /* Given an initializer INIT, return TRUE if INIT is zero or some
6849    aggregate of zeros.  Otherwise return FALSE.  */
6850 bool
6851 initializer_zerop (tree init)
6852 {
6853   tree elt;
6854
6855   STRIP_NOPS (init);
6856
6857   switch (TREE_CODE (init))
6858     {
6859     case INTEGER_CST:
6860       return integer_zerop (init);
6861
6862     case REAL_CST:
6863       /* ??? Note that this is not correct for C4X float formats.  There,
6864          a bit pattern of all zeros is 1.0; 0.0 is encoded with the most
6865          negative exponent.  */
6866       return real_zerop (init)
6867         && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (init));
6868
6869     case COMPLEX_CST:
6870       return integer_zerop (init)
6871         || (real_zerop (init)
6872             && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_REALPART (init)))
6873             && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_IMAGPART (init))));
6874
6875     case VECTOR_CST:
6876       for (elt = TREE_VECTOR_CST_ELTS (init); elt; elt = TREE_CHAIN (elt))
6877         if (!initializer_zerop (TREE_VALUE (elt)))
6878           return false;
6879       return true;
6880
6881     case CONSTRUCTOR:
6882       {
6883         unsigned HOST_WIDE_INT idx;
6884
6885         FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), idx, elt)
6886           if (!initializer_zerop (elt))
6887             return false;
6888         return true;
6889       }
6890
6891     default:
6892       return false;
6893     }
6894 }
6895
6896 /* Build an empty statement.  */
6897
6898 tree
6899 build_empty_stmt (void)
6900 {
6901   return build1 (NOP_EXPR, void_type_node, size_zero_node);
6902 }
6903
6904
6905 /* Build an OpenMP clause with code CODE.  */
6906
6907 tree
6908 build_omp_clause (enum omp_clause_code code)
6909 {
6910   tree t;
6911   int size, length;
6912
6913   length = omp_clause_num_ops[code];
6914   size = (sizeof (struct tree_omp_clause) + (length - 1) * sizeof (tree));
6915
6916   t = ggc_alloc (size);
6917   memset (t, 0, size);
6918   TREE_SET_CODE (t, OMP_CLAUSE);
6919   OMP_CLAUSE_SET_CODE (t, code);
6920
6921 #ifdef GATHER_STATISTICS
6922   tree_node_counts[(int) omp_clause_kind]++;
6923   tree_node_sizes[(int) omp_clause_kind] += size;
6924 #endif
6925
6926   return t;
6927 }
6928
6929
6930 /* Returns true if it is possible to prove that the index of
6931    an array access REF (an ARRAY_REF expression) falls into the
6932    array bounds.  */
6933
6934 bool
6935 in_array_bounds_p (tree ref)
6936 {
6937   tree idx = TREE_OPERAND (ref, 1);
6938   tree min, max;
6939
6940   if (TREE_CODE (idx) != INTEGER_CST)
6941     return false;
6942
6943   min = array_ref_low_bound (ref);
6944   max = array_ref_up_bound (ref);
6945   if (!min
6946       || !max
6947       || TREE_CODE (min) != INTEGER_CST
6948       || TREE_CODE (max) != INTEGER_CST)
6949     return false;
6950
6951   if (tree_int_cst_lt (idx, min)
6952       || tree_int_cst_lt (max, idx))
6953     return false;
6954
6955   return true;
6956 }
6957
6958 /* Returns true if it is possible to prove that the range of
6959    an array access REF (an ARRAY_RANGE_REF expression) falls
6960    into the array bounds.  */
6961
6962 bool
6963 range_in_array_bounds_p (tree ref)
6964 {
6965   tree domain_type = TYPE_DOMAIN (TREE_TYPE (ref));
6966   tree range_min, range_max, min, max;
6967
6968   range_min = TYPE_MIN_VALUE (domain_type);
6969   range_max = TYPE_MAX_VALUE (domain_type);
6970   if (!range_min
6971       || !range_max
6972       || TREE_CODE (range_min) != INTEGER_CST
6973       || TREE_CODE (range_max) != INTEGER_CST)
6974     return false;
6975
6976   min = array_ref_low_bound (ref);
6977   max = array_ref_up_bound (ref);
6978   if (!min
6979       || !max
6980       || TREE_CODE (min) != INTEGER_CST
6981       || TREE_CODE (max) != INTEGER_CST)
6982     return false;
6983
6984   if (tree_int_cst_lt (range_min, min)
6985       || tree_int_cst_lt (max, range_max))
6986     return false;
6987
6988   return true;
6989 }
6990
6991 /* Return true if T (assumed to be a DECL) is a global variable.  */
6992
6993 bool
6994 is_global_var (tree t)
6995 {
6996   if (MTAG_P (t))
6997     return (TREE_STATIC (t) || MTAG_GLOBAL (t));
6998   else
6999     return (TREE_STATIC (t) || DECL_EXTERNAL (t));
7000 }
7001
7002 /* Return true if T (assumed to be a DECL) must be assigned a memory
7003    location.  */
7004
7005 bool
7006 needs_to_live_in_memory (tree t)
7007 {
7008   return (TREE_ADDRESSABLE (t)
7009           || is_global_var (t)
7010           || (TREE_CODE (t) == RESULT_DECL
7011               && aggregate_value_p (t, current_function_decl)));
7012 }
7013
7014 /* There are situations in which a language considers record types
7015    compatible which have different field lists.  Decide if two fields
7016    are compatible.  It is assumed that the parent records are compatible.  */
7017
7018 bool
7019 fields_compatible_p (tree f1, tree f2)
7020 {
7021   if (!operand_equal_p (DECL_FIELD_BIT_OFFSET (f1),
7022                         DECL_FIELD_BIT_OFFSET (f2), OEP_ONLY_CONST))
7023     return false;
7024
7025   if (!operand_equal_p (DECL_FIELD_OFFSET (f1),
7026                         DECL_FIELD_OFFSET (f2), OEP_ONLY_CONST))
7027     return false;
7028
7029   if (!lang_hooks.types_compatible_p (TREE_TYPE (f1), TREE_TYPE (f2)))
7030     return false;
7031
7032   return true;
7033 }
7034
7035 /* Locate within RECORD a field that is compatible with ORIG_FIELD.  */
7036
7037 tree
7038 find_compatible_field (tree record, tree orig_field)
7039 {
7040   tree f;
7041
7042   for (f = TYPE_FIELDS (record); f ; f = TREE_CHAIN (f))
7043     if (TREE_CODE (f) == FIELD_DECL
7044         && fields_compatible_p (f, orig_field))
7045       return f;
7046
7047   /* ??? Why isn't this on the main fields list?  */
7048   f = TYPE_VFIELD (record);
7049   if (f && TREE_CODE (f) == FIELD_DECL
7050       && fields_compatible_p (f, orig_field))
7051     return f;
7052
7053   /* ??? We should abort here, but Java appears to do Bad Things
7054      with inherited fields.  */
7055   return orig_field;
7056 }
7057
7058 /* Return value of a constant X.  */
7059
7060 HOST_WIDE_INT
7061 int_cst_value (tree x)
7062 {
7063   unsigned bits = TYPE_PRECISION (TREE_TYPE (x));
7064   unsigned HOST_WIDE_INT val = TREE_INT_CST_LOW (x);
7065   bool negative = ((val >> (bits - 1)) & 1) != 0;
7066
7067   gcc_assert (bits <= HOST_BITS_PER_WIDE_INT);
7068
7069   if (negative)
7070     val |= (~(unsigned HOST_WIDE_INT) 0) << (bits - 1) << 1;
7071   else
7072     val &= ~((~(unsigned HOST_WIDE_INT) 0) << (bits - 1) << 1);
7073
7074   return val;
7075 }
7076
7077 /* Returns the greatest common divisor of A and B, which must be
7078    INTEGER_CSTs.  */
7079
7080 tree
7081 tree_fold_gcd (tree a, tree b)
7082 {
7083   tree a_mod_b;
7084   tree type = TREE_TYPE (a);
7085
7086   gcc_assert (TREE_CODE (a) == INTEGER_CST);
7087   gcc_assert (TREE_CODE (b) == INTEGER_CST);
7088
7089   if (integer_zerop (a))
7090     return b;
7091
7092   if (integer_zerop (b))
7093     return a;
7094
7095   if (tree_int_cst_sgn (a) == -1)
7096     a = fold_build2 (MULT_EXPR, type, a,
7097                      build_int_cst (type, -1));
7098
7099   if (tree_int_cst_sgn (b) == -1)
7100     b = fold_build2 (MULT_EXPR, type, b,
7101                      build_int_cst (type, -1));
7102
7103   while (1)
7104     {
7105       a_mod_b = fold_build2 (FLOOR_MOD_EXPR, type, a, b);
7106
7107       if (!TREE_INT_CST_LOW (a_mod_b)
7108           && !TREE_INT_CST_HIGH (a_mod_b))
7109         return b;
7110
7111       a = b;
7112       b = a_mod_b;
7113     }
7114 }
7115
7116 /* Returns unsigned variant of TYPE.  */
7117
7118 tree
7119 unsigned_type_for (tree type)
7120 {
7121   if (POINTER_TYPE_P (type))
7122     return lang_hooks.types.unsigned_type (size_type_node);
7123   return lang_hooks.types.unsigned_type (type);
7124 }
7125
7126 /* Returns signed variant of TYPE.  */
7127
7128 tree
7129 signed_type_for (tree type)
7130 {
7131   if (POINTER_TYPE_P (type))
7132     return lang_hooks.types.signed_type (size_type_node);
7133   return lang_hooks.types.signed_type (type);
7134 }
7135
7136 /* Returns the largest value obtainable by casting something in INNER type to
7137    OUTER type.  */
7138
7139 tree
7140 upper_bound_in_type (tree outer, tree inner)
7141 {
7142   unsigned HOST_WIDE_INT lo, hi;
7143   unsigned int det = 0;
7144   unsigned oprec = TYPE_PRECISION (outer);
7145   unsigned iprec = TYPE_PRECISION (inner);
7146   unsigned prec;
7147
7148   /* Compute a unique number for every combination.  */
7149   det |= (oprec > iprec) ? 4 : 0;
7150   det |= TYPE_UNSIGNED (outer) ? 2 : 0;
7151   det |= TYPE_UNSIGNED (inner) ? 1 : 0;
7152
7153   /* Determine the exponent to use.  */
7154   switch (det)
7155     {
7156     case 0:
7157     case 1:
7158       /* oprec <= iprec, outer: signed, inner: don't care.  */
7159       prec = oprec - 1;
7160       break;
7161     case 2:
7162     case 3:
7163       /* oprec <= iprec, outer: unsigned, inner: don't care.  */
7164       prec = oprec;
7165       break;
7166     case 4:
7167       /* oprec > iprec, outer: signed, inner: signed.  */
7168       prec = iprec - 1;
7169       break;
7170     case 5:
7171       /* oprec > iprec, outer: signed, inner: unsigned.  */
7172       prec = iprec;
7173       break;
7174     case 6:
7175       /* oprec > iprec, outer: unsigned, inner: signed.  */
7176       prec = oprec;
7177       break;
7178     case 7:
7179       /* oprec > iprec, outer: unsigned, inner: unsigned.  */
7180       prec = iprec;
7181       break;
7182     default:
7183       gcc_unreachable ();
7184     }
7185
7186   /* Compute 2^^prec - 1.  */
7187   if (prec <= HOST_BITS_PER_WIDE_INT)
7188     {
7189       hi = 0;
7190       lo = ((~(unsigned HOST_WIDE_INT) 0)
7191             >> (HOST_BITS_PER_WIDE_INT - prec));
7192     }
7193   else
7194     {
7195       hi = ((~(unsigned HOST_WIDE_INT) 0)
7196             >> (2 * HOST_BITS_PER_WIDE_INT - prec));
7197       lo = ~(unsigned HOST_WIDE_INT) 0;
7198     }
7199
7200   return build_int_cst_wide (outer, lo, hi);
7201 }
7202
7203 /* Returns the smallest value obtainable by casting something in INNER type to
7204    OUTER type.  */
7205
7206 tree
7207 lower_bound_in_type (tree outer, tree inner)
7208 {
7209   unsigned HOST_WIDE_INT lo, hi;
7210   unsigned oprec = TYPE_PRECISION (outer);
7211   unsigned iprec = TYPE_PRECISION (inner);
7212
7213   /* If OUTER type is unsigned, we can definitely cast 0 to OUTER type
7214      and obtain 0.  */
7215   if (TYPE_UNSIGNED (outer)
7216       /* If we are widening something of an unsigned type, OUTER type
7217          contains all values of INNER type.  In particular, both INNER
7218          and OUTER types have zero in common.  */
7219       || (oprec > iprec && TYPE_UNSIGNED (inner)))
7220     lo = hi = 0;
7221   else
7222     {
7223       /* If we are widening a signed type to another signed type, we
7224          want to obtain -2^^(iprec-1).  If we are keeping the
7225          precision or narrowing to a signed type, we want to obtain
7226          -2^(oprec-1).  */
7227       unsigned prec = oprec > iprec ? iprec : oprec;
7228
7229       if (prec <= HOST_BITS_PER_WIDE_INT)
7230         {
7231           hi = ~(unsigned HOST_WIDE_INT) 0;
7232           lo = (~(unsigned HOST_WIDE_INT) 0) << (prec - 1);
7233         }
7234       else
7235         {
7236           hi = ((~(unsigned HOST_WIDE_INT) 0)
7237                 << (prec - HOST_BITS_PER_WIDE_INT - 1));
7238           lo = 0;
7239         }
7240     }
7241
7242   return build_int_cst_wide (outer, lo, hi);
7243 }
7244
7245 /* Return nonzero if two operands that are suitable for PHI nodes are
7246    necessarily equal.  Specifically, both ARG0 and ARG1 must be either
7247    SSA_NAME or invariant.  Note that this is strictly an optimization.
7248    That is, callers of this function can directly call operand_equal_p
7249    and get the same result, only slower.  */
7250
7251 int
7252 operand_equal_for_phi_arg_p (tree arg0, tree arg1)
7253 {
7254   if (arg0 == arg1)
7255     return 1;
7256   if (TREE_CODE (arg0) == SSA_NAME || TREE_CODE (arg1) == SSA_NAME)
7257     return 0;
7258   return operand_equal_p (arg0, arg1, 0);
7259 }
7260
7261 /* Returns number of zeros at the end of binary representation of X.
7262
7263    ??? Use ffs if available?  */
7264
7265 tree
7266 num_ending_zeros (tree x)
7267 {
7268   unsigned HOST_WIDE_INT fr, nfr;
7269   unsigned num, abits;
7270   tree type = TREE_TYPE (x);
7271
7272   if (TREE_INT_CST_LOW (x) == 0)
7273     {
7274       num = HOST_BITS_PER_WIDE_INT;
7275       fr = TREE_INT_CST_HIGH (x);
7276     }
7277   else
7278     {
7279       num = 0;
7280       fr = TREE_INT_CST_LOW (x);
7281     }
7282
7283   for (abits = HOST_BITS_PER_WIDE_INT / 2; abits; abits /= 2)
7284     {
7285       nfr = fr >> abits;
7286       if (nfr << abits == fr)
7287         {
7288           num += abits;
7289           fr = nfr;
7290         }
7291     }
7292
7293   if (num > TYPE_PRECISION (type))
7294     num = TYPE_PRECISION (type);
7295
7296   return build_int_cst_type (type, num);
7297 }
7298
7299
7300 #define WALK_SUBTREE(NODE)                              \
7301   do                                                    \
7302     {                                                   \
7303       result = walk_tree (&(NODE), func, data, pset);   \
7304       if (result)                                       \
7305         return result;                                  \
7306     }                                                   \
7307   while (0)
7308
7309 /* This is a subroutine of walk_tree that walks field of TYPE that are to
7310    be walked whenever a type is seen in the tree.  Rest of operands and return
7311    value are as for walk_tree.  */
7312
7313 static tree
7314 walk_type_fields (tree type, walk_tree_fn func, void *data,
7315                   struct pointer_set_t *pset)
7316 {
7317   tree result = NULL_TREE;
7318
7319   switch (TREE_CODE (type))
7320     {
7321     case POINTER_TYPE:
7322     case REFERENCE_TYPE:
7323       /* We have to worry about mutually recursive pointers.  These can't
7324          be written in C.  They can in Ada.  It's pathological, but
7325          there's an ACATS test (c38102a) that checks it.  Deal with this
7326          by checking if we're pointing to another pointer, that one
7327          points to another pointer, that one does too, and we have no htab.
7328          If so, get a hash table.  We check three levels deep to avoid
7329          the cost of the hash table if we don't need one.  */
7330       if (POINTER_TYPE_P (TREE_TYPE (type))
7331           && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (type)))
7332           && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (TREE_TYPE (type))))
7333           && !pset)
7334         {
7335           result = walk_tree_without_duplicates (&TREE_TYPE (type),
7336                                                  func, data);
7337           if (result)
7338             return result;
7339
7340           break;
7341         }
7342
7343       /* ... fall through ... */
7344
7345     case COMPLEX_TYPE:
7346       WALK_SUBTREE (TREE_TYPE (type));
7347       break;
7348
7349     case METHOD_TYPE:
7350       WALK_SUBTREE (TYPE_METHOD_BASETYPE (type));
7351
7352       /* Fall through.  */
7353
7354     case FUNCTION_TYPE:
7355       WALK_SUBTREE (TREE_TYPE (type));
7356       {
7357         tree arg;
7358
7359         /* We never want to walk into default arguments.  */
7360         for (arg = TYPE_ARG_TYPES (type); arg; arg = TREE_CHAIN (arg))
7361           WALK_SUBTREE (TREE_VALUE (arg));
7362       }
7363       break;
7364
7365     case ARRAY_TYPE:
7366       /* Don't follow this nodes's type if a pointer for fear that we'll
7367          have infinite recursion.  Those types are uninteresting anyway.  */
7368       if (!POINTER_TYPE_P (TREE_TYPE (type))
7369           && TREE_CODE (TREE_TYPE (type)) != OFFSET_TYPE)
7370         WALK_SUBTREE (TREE_TYPE (type));
7371       WALK_SUBTREE (TYPE_DOMAIN (type));
7372       break;
7373
7374     case BOOLEAN_TYPE:
7375     case ENUMERAL_TYPE:
7376     case INTEGER_TYPE:
7377     case REAL_TYPE:
7378       WALK_SUBTREE (TYPE_MIN_VALUE (type));
7379       WALK_SUBTREE (TYPE_MAX_VALUE (type));
7380       break;
7381
7382     case OFFSET_TYPE:
7383       WALK_SUBTREE (TREE_TYPE (type));
7384       WALK_SUBTREE (TYPE_OFFSET_BASETYPE (type));
7385       break;
7386
7387     default:
7388       break;
7389     }
7390
7391   return NULL_TREE;
7392 }
7393
7394 /* Apply FUNC to all the sub-trees of TP in a pre-order traversal.  FUNC is
7395    called with the DATA and the address of each sub-tree.  If FUNC returns a
7396    non-NULL value, the traversal is stopped, and the value returned by FUNC
7397    is returned.  If PSET is non-NULL it is used to record the nodes visited,
7398    and to avoid visiting a node more than once.  */
7399
7400 tree
7401 walk_tree (tree *tp, walk_tree_fn func, void *data, struct pointer_set_t *pset)
7402 {
7403   enum tree_code code;
7404   int walk_subtrees;
7405   tree result;
7406
7407 #define WALK_SUBTREE_TAIL(NODE)                         \
7408   do                                                    \
7409     {                                                   \
7410        tp = & (NODE);                                   \
7411        goto tail_recurse;                               \
7412     }                                                   \
7413   while (0)
7414
7415  tail_recurse:
7416   /* Skip empty subtrees.  */
7417   if (!*tp)
7418     return NULL_TREE;
7419
7420   /* Don't walk the same tree twice, if the user has requested
7421      that we avoid doing so.  */
7422   if (pset && pointer_set_insert (pset, *tp))
7423     return NULL_TREE;
7424
7425   /* Call the function.  */
7426   walk_subtrees = 1;
7427   result = (*func) (tp, &walk_subtrees, data);
7428
7429   /* If we found something, return it.  */
7430   if (result)
7431     return result;
7432
7433   code = TREE_CODE (*tp);
7434
7435   /* Even if we didn't, FUNC may have decided that there was nothing
7436      interesting below this point in the tree.  */
7437   if (!walk_subtrees)
7438     {
7439       /* But we still need to check our siblings.  */
7440       if (code == TREE_LIST)
7441         WALK_SUBTREE_TAIL (TREE_CHAIN (*tp));
7442       else if (code == OMP_CLAUSE)
7443         WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7444       else
7445         return NULL_TREE;
7446     }
7447
7448   result = lang_hooks.tree_inlining.walk_subtrees (tp, &walk_subtrees, func,
7449                                                    data, pset);
7450   if (result || ! walk_subtrees)
7451     return result;
7452
7453   switch (code)
7454     {
7455     case ERROR_MARK:
7456     case IDENTIFIER_NODE:
7457     case INTEGER_CST:
7458     case REAL_CST:
7459     case VECTOR_CST:
7460     case STRING_CST:
7461     case BLOCK:
7462     case PLACEHOLDER_EXPR:
7463     case SSA_NAME:
7464     case FIELD_DECL:
7465     case RESULT_DECL:
7466       /* None of these have subtrees other than those already walked
7467          above.  */
7468       break;
7469
7470     case TREE_LIST:
7471       WALK_SUBTREE (TREE_VALUE (*tp));
7472       WALK_SUBTREE_TAIL (TREE_CHAIN (*tp));
7473       break;
7474
7475     case TREE_VEC:
7476       {
7477         int len = TREE_VEC_LENGTH (*tp);
7478
7479         if (len == 0)
7480           break;
7481
7482         /* Walk all elements but the first.  */
7483         while (--len)
7484           WALK_SUBTREE (TREE_VEC_ELT (*tp, len));
7485
7486         /* Now walk the first one as a tail call.  */
7487         WALK_SUBTREE_TAIL (TREE_VEC_ELT (*tp, 0));
7488       }
7489
7490     case COMPLEX_CST:
7491       WALK_SUBTREE (TREE_REALPART (*tp));
7492       WALK_SUBTREE_TAIL (TREE_IMAGPART (*tp));
7493
7494     case CONSTRUCTOR:
7495       {
7496         unsigned HOST_WIDE_INT idx;
7497         constructor_elt *ce;
7498
7499         for (idx = 0;
7500              VEC_iterate(constructor_elt, CONSTRUCTOR_ELTS (*tp), idx, ce);
7501              idx++)
7502           WALK_SUBTREE (ce->value);
7503       }
7504       break;
7505
7506     case SAVE_EXPR:
7507       WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, 0));
7508
7509     case BIND_EXPR:
7510       {
7511         tree decl;
7512         for (decl = BIND_EXPR_VARS (*tp); decl; decl = TREE_CHAIN (decl))
7513           {
7514             /* Walk the DECL_INITIAL and DECL_SIZE.  We don't want to walk
7515                into declarations that are just mentioned, rather than
7516                declared; they don't really belong to this part of the tree.
7517                And, we can see cycles: the initializer for a declaration
7518                can refer to the declaration itself.  */
7519             WALK_SUBTREE (DECL_INITIAL (decl));
7520             WALK_SUBTREE (DECL_SIZE (decl));
7521             WALK_SUBTREE (DECL_SIZE_UNIT (decl));
7522           }
7523         WALK_SUBTREE_TAIL (BIND_EXPR_BODY (*tp));
7524       }
7525
7526     case STATEMENT_LIST:
7527       {
7528         tree_stmt_iterator i;
7529         for (i = tsi_start (*tp); !tsi_end_p (i); tsi_next (&i))
7530           WALK_SUBTREE (*tsi_stmt_ptr (i));
7531       }
7532       break;
7533
7534     case OMP_CLAUSE:
7535       switch (OMP_CLAUSE_CODE (*tp))
7536         {
7537         case OMP_CLAUSE_PRIVATE:
7538         case OMP_CLAUSE_SHARED:
7539         case OMP_CLAUSE_FIRSTPRIVATE:
7540         case OMP_CLAUSE_LASTPRIVATE:
7541         case OMP_CLAUSE_COPYIN:
7542         case OMP_CLAUSE_COPYPRIVATE:
7543         case OMP_CLAUSE_IF:
7544         case OMP_CLAUSE_NUM_THREADS:
7545         case OMP_CLAUSE_SCHEDULE:
7546           WALK_SUBTREE (OMP_CLAUSE_OPERAND (*tp, 0));
7547           /* FALLTHRU */
7548
7549         case OMP_CLAUSE_NOWAIT:
7550         case OMP_CLAUSE_ORDERED:
7551         case OMP_CLAUSE_DEFAULT:
7552           WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7553
7554         case OMP_CLAUSE_REDUCTION:
7555           {
7556             int i;
7557             for (i = 0; i < 4; i++)
7558               WALK_SUBTREE (OMP_CLAUSE_OPERAND (*tp, i));
7559             WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7560           }
7561
7562         default:
7563           gcc_unreachable ();
7564         }
7565       break;
7566
7567     case TARGET_EXPR:
7568       {
7569         int i, len;
7570
7571         /* TARGET_EXPRs are peculiar: operands 1 and 3 can be the same.
7572            But, we only want to walk once.  */
7573         len = (TREE_OPERAND (*tp, 3) == TREE_OPERAND (*tp, 1)) ? 2 : 3;
7574         for (i = 0; i < len; ++i)
7575           WALK_SUBTREE (TREE_OPERAND (*tp, i));
7576         WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, len));
7577       }
7578
7579     case DECL_EXPR:
7580       /* Walk into various fields of the type that it's defining.  We only
7581          want to walk into these fields of a type in this case.  Note that
7582          decls get walked as part of the processing of a BIND_EXPR.
7583
7584          ??? Precisely which fields of types that we are supposed to walk in
7585          this case vs. the normal case aren't well defined.  */
7586       if (TREE_CODE (DECL_EXPR_DECL (*tp)) == TYPE_DECL
7587           && TREE_CODE (TREE_TYPE (DECL_EXPR_DECL (*tp))) != ERROR_MARK)
7588         {
7589           tree *type_p = &TREE_TYPE (DECL_EXPR_DECL (*tp));
7590
7591           /* Call the function for the type.  See if it returns anything or
7592              doesn't want us to continue.  If we are to continue, walk both
7593              the normal fields and those for the declaration case.  */
7594           result = (*func) (type_p, &walk_subtrees, data);
7595           if (result || !walk_subtrees)
7596             return NULL_TREE;
7597
7598           result = walk_type_fields (*type_p, func, data, pset);
7599           if (result)
7600             return result;
7601
7602           /* If this is a record type, also walk the fields.  */
7603           if (TREE_CODE (*type_p) == RECORD_TYPE
7604               || TREE_CODE (*type_p) == UNION_TYPE
7605               || TREE_CODE (*type_p) == QUAL_UNION_TYPE)
7606             {
7607               tree field;
7608
7609               for (field = TYPE_FIELDS (*type_p); field;
7610                    field = TREE_CHAIN (field))
7611                 {
7612                   /* We'd like to look at the type of the field, but we can
7613                      easily get infinite recursion.  So assume it's pointed
7614                      to elsewhere in the tree.  Also, ignore things that
7615                      aren't fields.  */
7616                   if (TREE_CODE (field) != FIELD_DECL)
7617                     continue;
7618
7619                   WALK_SUBTREE (DECL_FIELD_OFFSET (field));
7620                   WALK_SUBTREE (DECL_SIZE (field));
7621                   WALK_SUBTREE (DECL_SIZE_UNIT (field));
7622                   if (TREE_CODE (*type_p) == QUAL_UNION_TYPE)
7623                     WALK_SUBTREE (DECL_QUALIFIER (field));
7624                 }
7625             }
7626
7627           WALK_SUBTREE (TYPE_SIZE (*type_p));
7628           WALK_SUBTREE_TAIL (TYPE_SIZE_UNIT (*type_p));
7629         }
7630       /* FALLTHRU */
7631
7632     default:
7633       if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
7634         {
7635           int i, len;
7636
7637           /* Walk over all the sub-trees of this operand.  */
7638           len = TREE_CODE_LENGTH (code);
7639
7640           /* Go through the subtrees.  We need to do this in forward order so
7641              that the scope of a FOR_EXPR is handled properly.  */
7642           if (len)
7643             {
7644               for (i = 0; i < len - 1; ++i)
7645                 WALK_SUBTREE (TREE_OPERAND (*tp, i));
7646               WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, len - 1));
7647             }
7648         }
7649
7650       /* If this is a type, walk the needed fields in the type.  */
7651       else if (TYPE_P (*tp))
7652         return walk_type_fields (*tp, func, data, pset);
7653       break;
7654     }
7655
7656   /* We didn't find what we were looking for.  */
7657   return NULL_TREE;
7658
7659 #undef WALK_SUBTREE_TAIL
7660 }
7661 #undef WALK_SUBTREE
7662
7663 /* Like walk_tree, but does not walk duplicate nodes more than once.  */
7664
7665 tree
7666 walk_tree_without_duplicates (tree *tp, walk_tree_fn func, void *data)
7667 {
7668   tree result;
7669   struct pointer_set_t *pset;
7670
7671   pset = pointer_set_create ();
7672   result = walk_tree (tp, func, data, pset);
7673   pointer_set_destroy (pset);
7674   return result;
7675 }
7676
7677
7678 /* Return true if STMT is an empty statement or contains nothing but
7679    empty statements.  */
7680
7681 bool
7682 empty_body_p (tree stmt)
7683 {
7684   tree_stmt_iterator i;
7685   tree body;
7686
7687   if (IS_EMPTY_STMT (stmt))
7688     return true;
7689   else if (TREE_CODE (stmt) == BIND_EXPR)
7690     body = BIND_EXPR_BODY (stmt);
7691   else if (TREE_CODE (stmt) == STATEMENT_LIST)
7692     body = stmt;
7693   else
7694     return false;
7695
7696   for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i))
7697     if (!empty_body_p (tsi_stmt (i)))
7698       return false;
7699
7700   return true;
7701 }
7702
7703 #include "gt-tree.h"