gcc/tree-browser.c

   1 /* Tree browser.
   2    Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
   3    Contributed by Sebastian Pop <s.pop@laposte.net>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "tree.h"
  27 #include "tree-inline.h"
  28 #include "diagnostic.h"
  29 #include "hashtab.h"
  30
  31
  32 #define TB_OUT_FILE stdout
  33 #define TB_IN_FILE stdin
  34 #define TB_NIY fprintf (TB_OUT_FILE, "Sorry this command is not yet implemented.\n")
  35 #define TB_WF fprintf (TB_OUT_FILE, "Warning, this command failed.\n")
  36
  37
  38 /* Structures for handling Tree Browser's commands.  */
  39 #define DEFTBCODE(COMMAND, STRING, HELP)   COMMAND,
  40 enum TB_Comm_code {
  41 #include "tree-browser.def"
  42   TB_UNUSED_COMMAND
  43 };
  44 #undef DEFTBCODE
  45 typedef enum TB_Comm_code TB_CODE;
  46
  47 struct tb_command {
  48   const char *help_msg;
  49   const char *comm_text;
  50   size_t comm_len;
  51   TB_CODE comm_code;
  52 };
  53
  54 #define DEFTBCODE(code, str, help) { help, str, sizeof(str) - 1, code },
  55 static const struct tb_command tb_commands[] =
  56 {
  57 #include "tree-browser.def"
  58 };
  59 #undef DEFTBCODE
  60
  61 #define TB_COMMAND_LEN(N) (tb_commands[N].comm_len)
  62 #define TB_COMMAND_TEXT(N) (tb_commands[N].comm_text)
  63 #define TB_COMMAND_CODE(N) (tb_commands[N].comm_code)
  64 #define TB_COMMAND_HELP(N) (tb_commands[N].help_msg)
  65
  66
  67 /* Next structure is for parsing TREE_CODEs.  */
  68 struct tb_tree_code {
  69   enum tree_code code;
  70   const char *code_string;
  71   size_t code_string_len;
  72 };
  73
  74 #define DEFTREECODE(SYM, STRING, TYPE, NARGS) { SYM, STRING, sizeof (STRING) - 1 },
  75 static const struct tb_tree_code tb_tree_codes[] =
  76 {
  77 #include "tree.def"
  78 };
  79 #undef DEFTREECODE
  80
  81 #define TB_TREE_CODE(N) (tb_tree_codes[N].code)
  82 #define TB_TREE_CODE_TEXT(N) (tb_tree_codes[N].code_string)
  83 #define TB_TREE_CODE_LEN(N) (tb_tree_codes[N].code_string_len)
  84
  85
  86 /* Function declarations.  */
  87
  88 static long TB_getline (char **, long *, FILE *);
  89 static TB_CODE TB_get_command (char *);
  90 static enum tree_code TB_get_tree_code (char *);
  91 static tree find_node_with_code (tree *, int *, void *);
  92 static tree store_child_info (tree *, int *, void *);
  93 static void TB_update_up (tree);
  94 static tree TB_current_chain_node (tree);
  95 static tree TB_prev_expr (tree);
  96 static tree TB_next_expr (tree);
  97 static tree TB_up_expr (tree);
  98 static tree TB_first_in_bind (tree);
  99 static tree TB_last_in_bind (tree);
 100 static int  TB_parent_eq (const void *, const void *);
 101 static tree TB_history_prev (void);
 102
 103 /* FIXME: To be declared in a .h file.  */
 104 void browse_tree (tree);
 105
 106 /* Static variables.  */
 107 static htab_t TB_up_ht;
 108 static tree TB_history_stack = NULL_TREE;
 109 static int TB_verbose = 1;
 110
 111
 112 /* Entry point in the Tree Browser.  */
 113
 114 void
 115 browse_tree (tree begin)
 116 {
 117   tree head;
 118   TB_CODE tbc = TB_UNUSED_COMMAND;
 119   ssize_t rd;
 120   char *input = NULL;
 121   long input_size = 0;
 122
 123   fprintf (TB_OUT_FILE, "\nTree Browser\n");
 124
 125 #define TB_SET_HEAD(N) do {                                           \
 126   TB_history_stack = tree_cons (NULL_TREE, (N), TB_history_stack);    \
 127   head = N;                                                           \
 128   if (TB_verbose)                                                     \
 129     if (head)                                                         \
 130       {                                                               \
 131         print_generic_expr (TB_OUT_FILE, head, 0);                    \
 132         fprintf (TB_OUT_FILE, "\n");                                  \
 133       }                                                               \
 134 } while (0)
 135
 136   TB_SET_HEAD (begin);
 137
 138   /* Store in a hashtable information about previous and upper statements.  */
 139   {
 140     TB_up_ht = htab_create (1023, htab_hash_pointer, &TB_parent_eq, NULL);
 141     TB_update_up (head);
 142   }
 143
 144   while (24)
 145     {
 146       fprintf (TB_OUT_FILE, "TB> ");
 147       rd = TB_getline (&input, &input_size, TB_IN_FILE);
 148
 149       if (rd == -1)
 150         /* EOF.  */
 151         goto ret;
 152
 153       if (rd != 1)
 154         /* Get a new command.  Otherwise the user just pressed enter, and thus
 155            she expects the last command to be reexecuted.  */
 156         tbc = TB_get_command (input);
 157
 158       switch (tbc)
 159         {
 160         case TB_UPDATE_UP:
 161           TB_update_up (head);
 162           break;
 163
 164         case TB_MAX:
 165           if (head && (INTEGRAL_TYPE_P (head)
 166                        || TREE_CODE (head) == REAL_TYPE))
 167             TB_SET_HEAD (TYPE_MAX_VALUE (head));
 168           else
 169             TB_WF;
 170           break;
 171
 172         case TB_MIN:
 173           if (head && (INTEGRAL_TYPE_P (head)
 174                        || TREE_CODE (head) == REAL_TYPE))
 175             TB_SET_HEAD (TYPE_MIN_VALUE (head));
 176           else
 177             TB_WF;
 178           break;
 179
 180         case TB_ELT:
 181           if (head && TREE_CODE (head) == TREE_VEC)
 182             {
 183               /* This command takes another argument: the element number:
 184                  for example "elt 1".  */
 185               TB_NIY;
 186             }
 187           else if (head && TREE_CODE (head) == VECTOR_CST)
 188             {
 189               /* This command takes another argument: the element number:
 190                  for example "elt 1".  */
 191               TB_NIY;
 192             }
 193           else
 194             TB_WF;
 195           break;
 196
 197         case TB_VALUE:
 198           if (head && TREE_CODE (head) == TREE_LIST)
 199             TB_SET_HEAD (TREE_VALUE (head));
 200           else
 201             TB_WF;
 202           break;
 203
 204         case TB_PURPOSE:
 205           if (head && TREE_CODE (head) == TREE_LIST)
 206             TB_SET_HEAD (TREE_PURPOSE (head));
 207           else
 208             TB_WF;
 209           break;
 210
 211         case TB_IMAG:
 212           if (head && TREE_CODE (head) == COMPLEX_CST)
 213             TB_SET_HEAD (TREE_IMAGPART (head));
 214           else
 215             TB_WF;
 216           break;
 217
 218         case TB_REAL:
 219           if (head && TREE_CODE (head) == COMPLEX_CST)
 220             TB_SET_HEAD (TREE_REALPART (head));
 221           else
 222             TB_WF;
 223           break;
 224
 225         case TB_BLOCK:
 226           if (head && TREE_CODE (head) == BIND_EXPR)
 227             TB_SET_HEAD (TREE_OPERAND (head, 2));
 228           else
 229             TB_WF;
 230           break;
 231
 232         case TB_SUBBLOCKS:
 233           if (head && TREE_CODE (head) == BLOCK)
 234             TB_SET_HEAD (BLOCK_SUBBLOCKS (head));
 235           else
 236             TB_WF;
 237           break;
 238
 239         case TB_SUPERCONTEXT:
 240           if (head && TREE_CODE (head) == BLOCK)
 241             TB_SET_HEAD (BLOCK_SUPERCONTEXT (head));
 242           else
 243             TB_WF;
 244           break;
 245
 246         case TB_VARS:
 247           if (head && TREE_CODE (head) == BLOCK)
 248             TB_SET_HEAD (BLOCK_VARS (head));
 249           else if (head && TREE_CODE (head) == BIND_EXPR)
 250             TB_SET_HEAD (TREE_OPERAND (head, 0));
 251           else
 252             TB_WF;
 253           break;
 254
 255         case TB_REFERENCE_TO_THIS:
 256           if (head && TYPE_P (head))
 257             TB_SET_HEAD (TYPE_REFERENCE_TO (head));
 258           else
 259             TB_WF;
 260           break;
 261
 262         case TB_POINTER_TO_THIS:
 263           if (head && TYPE_P (head))
 264             TB_SET_HEAD (TYPE_POINTER_TO (head));
 265           else
 266             TB_WF;
 267           break;
 268
 269         case TB_BASETYPE:
 270           if (head && TREE_CODE (head) == OFFSET_TYPE)
 271             TB_SET_HEAD (TYPE_OFFSET_BASETYPE (head));
 272           else
 273             TB_WF;
 274           break;
 275
 276         case TB_ARG_TYPES:
 277           if (head && (TREE_CODE (head) == FUNCTION_TYPE
 278                        || TREE_CODE (head) == METHOD_TYPE))
 279             TB_SET_HEAD (TYPE_ARG_TYPES (head));
 280           else
 281             TB_WF;
 282           break;
 283
 284         case TB_METHOD_BASE_TYPE:
 285           if (head && (TREE_CODE (head) == FUNCTION_TYPE
 286                        || TREE_CODE (head) == METHOD_TYPE)
 287               && TYPE_METHOD_BASETYPE (head))
 288             TB_SET_HEAD (TYPE_METHOD_BASETYPE (head));
 289           else
 290             TB_WF;
 291           break;
 292
 293         case TB_FIELDS:
 294           if (head && (TREE_CODE (head) == RECORD_TYPE
 295                        || TREE_CODE (head) == UNION_TYPE
 296                        || TREE_CODE (head) == QUAL_UNION_TYPE))
 297             TB_SET_HEAD (TYPE_FIELDS (head));
 298           else
 299             TB_WF;
 300           break;
 301
 302         case TB_DOMAIN:
 303           if (head && TREE_CODE (head) == ARRAY_TYPE)
 304             TB_SET_HEAD (TYPE_DOMAIN (head));
 305           else
 306             TB_WF;
 307           break;
 308
 309         case TB_VALUES:
 310           if (head && TREE_CODE (head) == ENUMERAL_TYPE)
 311             TB_SET_HEAD (TYPE_VALUES (head));
 312           else
 313             TB_WF;
 314           break;
 315
 316         case TB_ARG_TYPE:
 317           if (head && TREE_CODE (head) == PARM_DECL)
 318             TB_SET_HEAD (DECL_ARG_TYPE (head));
 319           else
 320             TB_WF;
 321           break;
 322
 323         case TB_INITIAL:
 324           if (head && DECL_P (head))
 325             TB_SET_HEAD (DECL_INITIAL (head));
 326           else
 327             TB_WF;
 328           break;
 329
 330         case TB_RESULT:
 331           if (head && DECL_P (head))
 332             TB_SET_HEAD (DECL_RESULT_FLD (head));
 333           else
 334             TB_WF;
 335           break;
 336
 337         case TB_ARGUMENTS:
 338           if (head && DECL_P (head))
 339             TB_SET_HEAD (DECL_ARGUMENTS (head));
 340           else
 341             TB_WF;
 342           break;
 343
 344         case TB_ABSTRACT_ORIGIN:
 345           if (head && DECL_P (head))
 346             TB_SET_HEAD (DECL_ABSTRACT_ORIGIN (head));
 347           else if (head && TREE_CODE (head) == BLOCK)
 348             TB_SET_HEAD (BLOCK_ABSTRACT_ORIGIN (head));
 349           else
 350             TB_WF;
 351           break;
 352
 353         case TB_ATTRIBUTES:
 354           if (head && DECL_P (head))
 355             TB_SET_HEAD (DECL_ATTRIBUTES (head));
 356           else if (head && TYPE_P (head))
 357             TB_SET_HEAD (TYPE_ATTRIBUTES (head));
 358           else
 359             TB_WF;
 360           break;
 361
 362         case TB_CONTEXT:
 363           if (head && DECL_P (head))
 364             TB_SET_HEAD (DECL_CONTEXT (head));
 365           else if (head && TYPE_P (head)
 366                    && TYPE_CONTEXT (head))
 367             TB_SET_HEAD (TYPE_CONTEXT (head));
 368           else
 369             TB_WF;
 370           break;
 371
 372         case TB_OFFSET:
 373           if (head && TREE_CODE (head) == FIELD_DECL)
 374             TB_SET_HEAD (DECL_FIELD_OFFSET (head));
 375           else
 376             TB_WF;
 377           break;
 378
 379         case TB_BIT_OFFSET:
 380           if (head && TREE_CODE (head) == FIELD_DECL)
 381             TB_SET_HEAD (DECL_FIELD_BIT_OFFSET (head));
 382           else
 383             TB_WF;
 384           break;
 385
 386         case TB_UNIT_SIZE:
 387           if (head && DECL_P (head))
 388             TB_SET_HEAD (DECL_SIZE_UNIT (head));
 389           else if (head && TYPE_P (head))
 390             TB_SET_HEAD (TYPE_SIZE_UNIT (head));
 391           else
 392             TB_WF;
 393           break;
 394
 395         case TB_SIZE:
 396           if (head && DECL_P (head))
 397             TB_SET_HEAD (DECL_SIZE (head));
 398           else if (head && TYPE_P (head))
 399             TB_SET_HEAD (TYPE_SIZE (head));
 400           else
 401             TB_WF;
 402           break;
 403
 404         case TB_TYPE:
 405           if (head && TREE_TYPE (head))
 406             TB_SET_HEAD (TREE_TYPE (head));
 407           else
 408             TB_WF;
 409           break;
 410
 411         case TB_DECL_SAVED_TREE:
 412           if (head && TREE_CODE (head) == FUNCTION_DECL
 413               && DECL_SAVED_TREE (head))
 414             TB_SET_HEAD (DECL_SAVED_TREE (head));
 415           else
 416             TB_WF;
 417           break;
 418
 419         case TB_BODY:
 420           if (head && TREE_CODE (head) == BIND_EXPR)
 421             TB_SET_HEAD (TREE_OPERAND (head, 1));
 422           else
 423             TB_WF;
 424           break;
 425
 426         case TB_CHILD_0:
 427           if (head && EXPR_P (head) && TREE_OPERAND (head, 0))
 428             TB_SET_HEAD (TREE_OPERAND (head, 0));
 429           else
 430             TB_WF;
 431           break;
 432
 433         case TB_CHILD_1:
 434           if (head && EXPR_P (head) && TREE_OPERAND (head, 1))
 435             TB_SET_HEAD (TREE_OPERAND (head, 1));
 436           else
 437             TB_WF;
 438           break;
 439
 440         case TB_CHILD_2:
 441           if (head && EXPR_P (head) && TREE_OPERAND (head, 2))
 442             TB_SET_HEAD (TREE_OPERAND (head, 2));
 443           else
 444             TB_WF;
 445           break;
 446
 447         case TB_CHILD_3:
 448           if (head && EXPR_P (head) && TREE_OPERAND (head, 3))
 449             TB_SET_HEAD (TREE_OPERAND (head, 3));
 450           else
 451             TB_WF;
 452           break;
 453
 454         case TB_PRINT:
 455           if (head)
 456             debug_tree (head);
 457           else
 458             TB_WF;
 459           break;
 460
 461         case TB_PRETTY_PRINT:
 462           if (head)
 463             {
 464               print_generic_stmt (TB_OUT_FILE, head, 0);
 465               fprintf (TB_OUT_FILE, "\n");
 466             }
 467           else
 468             TB_WF;
 469           break;
 470
 471         case TB_SEARCH_NAME:
 472
 473           break;
 474
 475         case TB_SEARCH_CODE:
 476           {
 477             enum tree_code code;
 478             char *arg_text;
 479
 480             arg_text = strchr (input, ' ');
 481             if (arg_text == NULL)
 482               {
 483                 fprintf (TB_OUT_FILE, "First argument is missing.  This isn't a valid search command.  \n");
 484                 break;
 485               }
 486             code = TB_get_tree_code (arg_text + 1);
 487
 488             /* Search in the subtree a node with the given code.  */
 489             {
 490               tree res;
 491
 492               res = walk_tree (&head, find_node_with_code, &code, NULL);
 493               if (res == NULL_TREE)
 494                 {
 495                   fprintf (TB_OUT_FILE, "There's no node with this code (reachable via the walk_tree function from this node).\n");
 496                 }
 497               else
 498                 {
 499                   fprintf (TB_OUT_FILE, "Achoo!  I got this node in the tree.\n");
 500                   TB_SET_HEAD (res);
 501                 }
 502             }
 503             break;
 504           }
 505
 506 #define TB_MOVE_HEAD(FCT) do {       \
 507   if (head)                          \
 508     {                                \
 509       tree t;                        \
 510       t = FCT (head);                \
 511       if (t)                         \
 512         TB_SET_HEAD (t);             \
 513       else                           \
 514         TB_WF;                       \
 515     }                                \
 516   else                               \
 517     TB_WF;                           \
 518 } while (0)
 519
 520         case TB_FIRST:
 521           TB_MOVE_HEAD (TB_first_in_bind);
 522           break;
 523
 524         case TB_LAST:
 525           TB_MOVE_HEAD (TB_last_in_bind);
 526           break;
 527
 528         case TB_UP:
 529           TB_MOVE_HEAD (TB_up_expr);
 530           break;
 531
 532         case TB_PREV:
 533           TB_MOVE_HEAD (TB_prev_expr);
 534           break;
 535
 536         case TB_NEXT:
 537           TB_MOVE_HEAD (TB_next_expr);
 538           break;
 539
 540         case TB_HPREV:
 541           /* This command is a little bit special, since it deals with history
 542              stack.  For this reason it should keep the "head = ..." statement
 543              and not use TB_MOVE_HEAD.  */
 544           if (head)
 545             {
 546               tree t;
 547               t = TB_history_prev ();
 548               if (t)
 549                 {
 550                   head = t;
 551                   if (TB_verbose)
 552                     {
 553                       print_generic_expr (TB_OUT_FILE, head, 0);
 554                       fprintf (TB_OUT_FILE, "\n");
 555                     }
 556                 }
 557               else
 558                 TB_WF;
 559             }
 560           else
 561             TB_WF;
 562           break;
 563
 564         case TB_CHAIN:
 565           /* Don't go further if it's the last node in this chain.  */
 566           if (head && TREE_CODE (head) == BLOCK)
 567             TB_SET_HEAD (BLOCK_CHAIN (head));
 568           else if (head && TREE_CHAIN (head))
 569             TB_SET_HEAD (TREE_CHAIN (head));
 570           else
 571             TB_WF;
 572           break;
 573
 574         case TB_FUN:
 575           /* Go up to the current function declaration.  */
 576           TB_SET_HEAD (current_function_decl);
 577           fprintf (TB_OUT_FILE, "Current function declaration.\n");
 578           break;
 579
 580         case TB_HELP:
 581           /* Display a help message.  */
 582           {
 583             int i;
 584             fprintf (TB_OUT_FILE, "Possible commands are:\n\n");
 585             for (i = 0; i < TB_UNUSED_COMMAND; i++)
 586               {
 587                 fprintf (TB_OUT_FILE, "%20s  -  %s\n", TB_COMMAND_TEXT (i), TB_COMMAND_HELP (i));
 588               }
 589           }
 590           break;
 591
 592         case TB_VERBOSE:
 593           if (TB_verbose == 0)
 594             {
 595               TB_verbose = 1;
 596               fprintf (TB_OUT_FILE, "Verbose on.\n");
 597             }
 598           else
 599             {
 600               TB_verbose = 0;
 601               fprintf (TB_OUT_FILE, "Verbose off.\n");
 602             }
 603           break;
 604
 605         case TB_EXIT:
 606         case TB_QUIT:
 607           /* Just exit from this function.  */
 608           goto ret;
 609
 610         default:
 611           TB_NIY;
 612         }
 613     }
 614
 615  ret:;
 616   htab_delete (TB_up_ht);
 617   return;
 618 }
 619
 620
 621 /* Search the first node in this BIND_EXPR.  */
 622
 623 static tree
 624 TB_first_in_bind (tree node)
 625 {
 626   tree t;
 627
 628   if (node == NULL_TREE)
 629     return NULL_TREE;
 630
 631   while ((t = TB_prev_expr (node)))
 632     node = t;
 633
 634   return node;
 635 }
 636
 637 /* Search the last node in this BIND_EXPR.  */
 638
 639 static tree
 640 TB_last_in_bind (tree node)
 641 {
 642   tree t;
 643
 644   if (node == NULL_TREE)
 645     return NULL_TREE;
 646
 647   while ((t = TB_next_expr (node)))
 648     node = t;
 649
 650   return node;
 651 }
 652
 653 /* Search the parent expression for this node.  */
 654
 655 static tree
 656 TB_up_expr (tree node)
 657 {
 658   tree res;
 659   if (node == NULL_TREE)
 660     return NULL_TREE;
 661
 662   res = (tree) htab_find (TB_up_ht, node);
 663   return res;
 664 }
 665
 666 /* Search the previous expression in this BIND_EXPR.  */
 667
 668 static tree
 669 TB_prev_expr (tree node)
 670 {
 671   node = TB_current_chain_node (node);
 672
 673   if (node == NULL_TREE)
 674     return NULL_TREE;
 675
 676   node = TB_up_expr (node);
 677   if (node && TREE_CODE (node) == COMPOUND_EXPR)
 678     return node;
 679   else
 680     return NULL_TREE;
 681 }
 682
 683 /* Search the next expression in this BIND_EXPR.  */
 684
 685 static tree
 686 TB_next_expr (tree node)
 687 {
 688   node = TB_current_chain_node (node);
 689
 690   if (node == NULL_TREE)
 691     return NULL_TREE;
 692
 693   node = TREE_OPERAND (node, 1);
 694   return node;
 695 }
 696
 697 static tree
 698 TB_current_chain_node (tree node)
 699 {
 700   if (node == NULL_TREE)
 701     return NULL_TREE;
 702
 703   if (TREE_CODE (node) == COMPOUND_EXPR)
 704     return node;
 705
 706   node = TB_up_expr (node);
 707   if (node)
 708     {
 709       if (TREE_CODE (node) == COMPOUND_EXPR)
 710         return node;
 711
 712       node = TB_up_expr (node);
 713       if (TREE_CODE (node) == COMPOUND_EXPR)
 714         return node;
 715     }
 716
 717   return NULL_TREE;
 718 }
 719
 720 /* For each node store in its children nodes that the current node is their
 721    parent.  This function is used by walk_tree.  */
 722
 723 static tree
 724 store_child_info (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
 725                   void *data ATTRIBUTE_UNUSED)
 726 {
 727   tree node;
 728   void **slot;
 729
 730   node = *tp;
 731
 732   /* 'node' is the parent of 'TREE_OPERAND (node, *)'.  */
 733   if (EXPR_P (node))
 734     {
 735       int n = TREE_OPERAND_LENGTH (node);
 736       int i;
 737       for (i = 0; i < n; i++)
 738         {
 739           tree op = TREE_OPERAND (node, i);
 740           slot = htab_find_slot (TB_up_ht, op, INSERT);
 741           *slot = (void *) node;
 742         }
 743     }
 744
 745   /* Never stop walk_tree.  */
 746   return NULL_TREE;
 747 }
 748
 749 /* Function used in TB_up_ht.  */
 750
 751 static int
 752 TB_parent_eq (const void *p1, const void *p2)
 753 {
 754   tree node, parent;
 755   node = (tree) p2;
 756   parent = (tree) p1;
 757
 758   if (p1 == NULL || p2 == NULL)
 759     return 0;
 760
 761   if (EXPR_P (parent))
 762     {
 763       int n = TREE_OPERAND_LENGTH (parent);
 764       int i;
 765       for (i = 0; i < n; i++)
 766         if (node == TREE_OPERAND (parent, i))
 767           return 1;
 768     }
 769   return 0;
 770 }
 771
 772 /* Update information about upper expressions in the hash table.  */
 773
 774 static void
 775 TB_update_up (tree node)
 776 {
 777   while (node)
 778     {
 779       walk_tree (&node, store_child_info, NULL, NULL);
 780
 781       /* Walk function's body.  */
 782       if (TREE_CODE (node) == FUNCTION_DECL)
 783         if (DECL_SAVED_TREE (node))
 784           walk_tree (&DECL_SAVED_TREE (node), store_child_info, NULL, NULL);
 785
 786       /* Walk rest of the chain.  */
 787       node = TREE_CHAIN (node);
 788     }
 789   fprintf (TB_OUT_FILE, "Up/prev expressions updated.\n");
 790 }
 791
 792 /* Parse the input string for determining the command the user asked for.  */
 793
 794 static TB_CODE
 795 TB_get_command (char *input)
 796 {
 797   unsigned int mn, size_tok;
 798   int comp;
 799   char *space;
 800
 801   space = strchr (input, ' ');
 802   if (space != NULL)
 803     size_tok = strlen (input) - strlen (space);
 804   else
 805     size_tok = strlen (input) - 1;
 806
 807   for (mn = 0; mn < TB_UNUSED_COMMAND; mn++)
 808     {
 809       if (size_tok != TB_COMMAND_LEN (mn))
 810         continue;
 811
 812       comp = memcmp (input, TB_COMMAND_TEXT (mn), TB_COMMAND_LEN (mn));
 813       if (comp == 0)
 814         /* Here we just determined the command.  If this command takes
 815            an argument, then the argument is determined later.  */
 816         return TB_COMMAND_CODE (mn);
 817     }
 818
 819   /* Not a valid command.  */
 820   return TB_UNUSED_COMMAND;
 821 }
 822
 823 /* Parse the input string for determining the tree code.  */
 824
 825 static enum tree_code
 826 TB_get_tree_code (char *input)
 827 {
 828   unsigned int mn, size_tok;
 829   int comp;
 830   char *space;
 831
 832   space = strchr (input, ' ');
 833   if (space != NULL)
 834     size_tok = strlen (input) - strlen (space);
 835   else
 836     size_tok = strlen (input) - 1;
 837
 838   for (mn = 0; mn < LAST_AND_UNUSED_TREE_CODE; mn++)
 839     {
 840       if (size_tok != TB_TREE_CODE_LEN (mn))
 841         continue;
 842
 843       comp = memcmp (input, TB_TREE_CODE_TEXT (mn), TB_TREE_CODE_LEN (mn));
 844       if (comp == 0)
 845         {
 846           fprintf (TB_OUT_FILE, "%s\n", TB_TREE_CODE_TEXT (mn));
 847           return TB_TREE_CODE (mn);
 848         }
 849     }
 850
 851   /* This isn't a valid code.  */
 852   return LAST_AND_UNUSED_TREE_CODE;
 853 }
 854
 855 /* Find a node with a given code.  This function is used as an argument to
 856    walk_tree.  */
 857
 858 static tree
 859 find_node_with_code (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
 860                      void *data)
 861 {
 862   enum tree_code *code;
 863   code = (enum tree_code *) data;
 864   if (*code == TREE_CODE (*tp))
 865     return *tp;
 866
 867   return NULL_TREE;
 868 }
 869
 870 /* Returns a pointer to the last visited node.  */
 871
 872 static tree
 873 TB_history_prev (void)
 874 {
 875   if (TB_history_stack)
 876     {
 877       TB_history_stack = TREE_CHAIN (TB_history_stack);
 878       if (TB_history_stack)
 879         return TREE_VALUE (TB_history_stack);
 880     }
 881   return NULL_TREE;
 882 }
 883
 884 /* Read up to (and including) a '\n' from STREAM into *LINEPTR
 885    (and null-terminate it). *LINEPTR is a pointer returned from malloc
 886    (or NULL), pointing to *N characters of space.  It is realloc'd as
 887    necessary.  Returns the number of characters read (not including the
 888    null terminator), or -1 on error or EOF.
 889    This function comes from sed (and is supposed to be a portable version
 890    of getline).  */
 891
 892 static long
 893 TB_getline (char **lineptr, long *n, FILE *stream)
 894 {
 895   char *line, *p;
 896   long size, copy;
 897
 898   if (lineptr == NULL || n == NULL)
 899     {
 900       errno = EINVAL;
 901       return -1;
 902     }
 903
 904   if (ferror (stream))
 905     return -1;
 906
 907   /* Make sure we have a line buffer to start with.  */
 908   if (*lineptr == NULL || *n < 2) /* !seen and no buf yet need 2 chars.  */
 909     {
 910 #ifndef MAX_CANON
 911 #define MAX_CANON       256
 912 #endif
 913       line = (char *) xrealloc (*lineptr, MAX_CANON);
 914       if (line == NULL)
 915         return -1;
 916       *lineptr = line;
 917       *n = MAX_CANON;
 918     }
 919
 920   line = *lineptr;
 921   size = *n;
 922
 923   copy = size;
 924   p = line;
 925
 926   while (1)
 927     {
 928       long len;
 929
 930       while (--copy > 0)
 931         {
 932           register int c = getc (stream);
 933           if (c == EOF)
 934             goto lose;
 935           else if ((*p++ = c) == '\n')
 936             goto win;
 937         }
 938
 939       /* Need to enlarge the line buffer.  */
 940       len = p - line;
 941       size *= 2;
 942       line = (char *) xrealloc (line, size);
 943       if (line == NULL)
 944         goto lose;
 945       *lineptr = line;
 946       *n = size;
 947       p = line + len;
 948       copy = size - len;
 949     }
 950
 951  lose:
 952   if (p == *lineptr)
 953     return -1;
 954
 955   /* Return a partial line since we got an error in the middle.  */
 956  win:
 957 #if defined(WIN32) || defined(_WIN32) || defined(__CYGWIN__) || defined(MSDOS)
 958   if (p - 2 >= *lineptr && p[-2] == '\r')
 959     p[-2] = p[-1], --p;
 960 #endif
 961   *p = '\0';
 962   return p - *lineptr;
 963 }