gcc/c-common.c

   1 /* Subroutines shared by all languages that are variants of C.
   2    Copyright (C) 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
   3
   4 This file is part of GNU CC.
   5
   6 GNU CC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU CC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU CC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #include "config.h"
  21 #include "tree.h"
  22 #include "c-lex.h"
  23 #include "c-tree.h"
  24 #include "flags.h"
  25 #include "obstack.h"
  26 #include <stdio.h>
  27 #include <ctype.h>
  28
  29 extern struct obstack permanent_obstack;
  30
  31 enum attrs {A_PACKED, A_NOCOMMON, A_NORETURN, A_CONST, A_T_UNION,
  32             A_CONSTRUCTOR, A_DESTRUCTOR, A_MODE, A_SECTION, A_ALIGNED,
  33             A_UNUSED, A_FORMAT, A_WEAK, A_ALIAS};
  34
  35 static void declare_hidden_char_array   PROTO((char *, char *));
  36 static void add_attribute               PROTO((enum attrs, char *,
  37                                                int, int, int));
  38 static void init_attributes             PROTO((void));
  39
  40 /* Make bindings for __FUNCTION__ and __PRETTY_FUNCTION__.  */
  41
  42 void
  43 declare_function_name ()
  44 {
  45   char *name, *printable_name;
  46
  47   if (current_function_decl == NULL)
  48     {
  49       name = "";
  50       printable_name = "top level";
  51     }
  52   else
  53     {
  54       char *kind = "function";
  55       if (TREE_CODE (TREE_TYPE (current_function_decl)) == METHOD_TYPE)
  56         kind = "method";
  57       /* Allow functions to be nameless (such as artificial ones).  */
  58       if (DECL_NAME (current_function_decl))
  59         name = IDENTIFIER_POINTER (DECL_NAME (current_function_decl));
  60       else
  61         name = "";
  62       printable_name = (*decl_printable_name) (current_function_decl, &kind);
  63     }
  64
  65   declare_hidden_char_array ("__FUNCTION__", name);
  66   declare_hidden_char_array ("__PRETTY_FUNCTION__", printable_name);
  67 }
  68
  69 static void
  70 declare_hidden_char_array (name, value)
  71      char *name, *value;
  72 {
  73   tree decl, type, init;
  74   int vlen;
  75
  76   /* If the default size of char arrays isn't big enough for the name,
  77      or if we want to give warnings for large objects, make a bigger one.  */
  78   vlen = strlen (value) + 1;
  79   type = char_array_type_node;
  80   if (TREE_INT_CST_LOW (TYPE_MAX_VALUE (TREE_TYPE (type))) < vlen
  81       || warn_larger_than)
  82     type = build_array_type (char_type_node,
  83                              build_index_type (build_int_2 (vlen, 0)));
  84   push_obstacks_nochange ();
  85   decl = build_decl (VAR_DECL, get_identifier (name), type);
  86   TREE_STATIC (decl) = 1;
  87   TREE_READONLY (decl) = 1;
  88   TREE_ASM_WRITTEN (decl) = 1;
  89   DECL_SOURCE_LINE (decl) = 0;
  90   DECL_ARTIFICIAL (decl) = 1;
  91   DECL_IN_SYSTEM_HEADER (decl) = 1;
  92   DECL_IGNORED_P (decl) = 1;
  93   init = build_string (vlen, value);
  94   TREE_TYPE (init) = type;
  95   DECL_INITIAL (decl) = init;
  96   finish_decl (pushdecl (decl), init, NULL_TREE);
  97 }
  98
  99 /* Given a chain of STRING_CST nodes,
 100    concatenate them into one STRING_CST
 101    and give it a suitable array-of-chars data type.  */
 102
 103 tree
 104 combine_strings (strings)
 105      tree strings;
 106 {
 107   register tree value, t;
 108   register int length = 1;
 109   int wide_length = 0;
 110   int wide_flag = 0;
 111   int wchar_bytes = TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT;
 112   int nchars;
 113
 114   if (TREE_CHAIN (strings))
 115     {
 116       /* More than one in the chain, so concatenate.  */
 117       register char *p, *q;
 118
 119       /* Don't include the \0 at the end of each substring,
 120          except for the last one.
 121          Count wide strings and ordinary strings separately.  */
 122       for (t = strings; t; t = TREE_CHAIN (t))
 123         {
 124           if (TREE_TYPE (t) == wchar_array_type_node)
 125             {
 126               wide_length += (TREE_STRING_LENGTH (t) - wchar_bytes);
 127               wide_flag = 1;
 128             }
 129           else
 130             length += (TREE_STRING_LENGTH (t) - 1);
 131         }
 132
 133       /* If anything is wide, the non-wides will be converted,
 134          which makes them take more space.  */
 135       if (wide_flag)
 136         length = length * wchar_bytes + wide_length;
 137
 138       p = savealloc (length);
 139
 140       /* Copy the individual strings into the new combined string.
 141          If the combined string is wide, convert the chars to ints
 142          for any individual strings that are not wide.  */
 143
 144       q = p;
 145       for (t = strings; t; t = TREE_CHAIN (t))
 146         {
 147           int len = (TREE_STRING_LENGTH (t)
 148                      - ((TREE_TYPE (t) == wchar_array_type_node)
 149                         ? wchar_bytes : 1));
 150           if ((TREE_TYPE (t) == wchar_array_type_node) == wide_flag)
 151             {
 152               bcopy (TREE_STRING_POINTER (t), q, len);
 153               q += len;
 154             }
 155           else
 156             {
 157               int i;
 158               for (i = 0; i < len; i++)
 159                 ((int *) q)[i] = TREE_STRING_POINTER (t)[i];
 160               q += len * wchar_bytes;
 161             }
 162         }
 163       if (wide_flag)
 164         {
 165           int i;
 166           for (i = 0; i < wchar_bytes; i++)
 167             *q++ = 0;
 168         }
 169       else
 170         *q = 0;
 171
 172       value = make_node (STRING_CST);
 173       TREE_STRING_POINTER (value) = p;
 174       TREE_STRING_LENGTH (value) = length;
 175       TREE_CONSTANT (value) = 1;
 176     }
 177   else
 178     {
 179       value = strings;
 180       length = TREE_STRING_LENGTH (value);
 181       if (TREE_TYPE (value) == wchar_array_type_node)
 182         wide_flag = 1;
 183     }
 184
 185   /* Compute the number of elements, for the array type.  */
 186   nchars = wide_flag ? length / wchar_bytes : length;
 187
 188   /* Create the array type for the string constant.
 189      -Wwrite-strings says make the string constant an array of const char
 190      so that copying it to a non-const pointer will get a warning.  */
 191   if (warn_write_strings
 192       && (! flag_traditional  && ! flag_writable_strings))
 193     {
 194       tree elements
 195         = build_type_variant (wide_flag ? wchar_type_node : char_type_node,
 196                               1, 0);
 197       TREE_TYPE (value)
 198         = build_array_type (elements,
 199                             build_index_type (build_int_2 (nchars - 1, 0)));
 200     }
 201   else
 202     TREE_TYPE (value)
 203       = build_array_type (wide_flag ? wchar_type_node : char_type_node,
 204                           build_index_type (build_int_2 (nchars - 1, 0)));
 205   TREE_CONSTANT (value) = 1;
 206   TREE_STATIC (value) = 1;
 207   return value;
 208 }
 209 \f
 210 /* To speed up processing of attributes, we maintain an array of
 211    IDENTIFIER_NODES and the corresponding attribute types.  */
 212
 213 /* Array to hold attribute information.  */
 214
 215 static struct {enum attrs id; tree name; int min, max, decl_req;} attrtab[50];
 216
 217 static int attrtab_idx = 0;
 218
 219 /* Add an entry to the attribute table above.  */
 220
 221 static void
 222 add_attribute (id, string, min_len, max_len, decl_req)
 223      enum attrs id;
 224      char *string;
 225      int min_len, max_len;
 226      int decl_req;
 227 {
 228   char buf[100];
 229
 230   attrtab[attrtab_idx].id = id;
 231   attrtab[attrtab_idx].name = get_identifier (string);
 232   attrtab[attrtab_idx].min = min_len;
 233   attrtab[attrtab_idx].max = max_len;
 234   attrtab[attrtab_idx++].decl_req = decl_req;
 235
 236   sprintf (buf, "__%s__", string);
 237
 238   attrtab[attrtab_idx].id = id;
 239   attrtab[attrtab_idx].name = get_identifier (buf);
 240   attrtab[attrtab_idx].min = min_len;
 241   attrtab[attrtab_idx].max = max_len;
 242   attrtab[attrtab_idx++].decl_req = decl_req;
 243 }
 244
 245 /* Initialize attribute table.  */
 246
 247 static void
 248 init_attributes ()
 249 {
 250   add_attribute (A_PACKED, "packed", 0, 0, 0);
 251   add_attribute (A_NOCOMMON, "nocommon", 0, 0, 1);
 252   add_attribute (A_NORETURN, "noreturn", 0, 0, 1);
 253   add_attribute (A_NORETURN, "volatile", 0, 0, 1);
 254   add_attribute (A_UNUSED, "unused", 0, 0, 1);
 255   add_attribute (A_CONST, "const", 0, 0, 1);
 256   add_attribute (A_T_UNION, "transparent_union", 0, 0, 0);
 257   add_attribute (A_CONSTRUCTOR, "constructor", 0, 0, 1);
 258   add_attribute (A_DESTRUCTOR, "destructor", 0, 0, 1);
 259   add_attribute (A_MODE, "mode", 1, 1, 1);
 260   add_attribute (A_SECTION, "section", 1, 1, 1);
 261   add_attribute (A_ALIGNED, "aligned", 0, 1, 0);
 262   add_attribute (A_FORMAT, "format", 3, 3, 1);
 263   add_attribute (A_WEAK, "weak", 0, 0, 1);
 264   add_attribute (A_ALIAS, "alias", 1, 1, 1);
 265 }
 266 \f
 267 /* Process the attributes listed in ATTRIBUTES and PREFIX_ATTRIBUTES
 268    and install them in NODE, which is either a DECL (including a TYPE_DECL)
 269    or a TYPE.  PREFIX_ATTRIBUTES can appear after the declaration specifiers
 270    and declaration modifiers but before the declaration proper. */
 271
 272 void
 273 decl_attributes (node, attributes, prefix_attributes)
 274      tree node, attributes, prefix_attributes;
 275 {
 276   tree decl = 0, type;
 277   int is_type;
 278   tree a;
 279
 280   if (attrtab_idx == 0)
 281     init_attributes ();
 282
 283   if (TREE_CODE_CLASS (TREE_CODE (node)) == 'd')
 284     {
 285       decl = node;
 286       type = TREE_TYPE (decl);
 287       is_type = TREE_CODE (node) == TYPE_DECL;
 288     }
 289   else if (TREE_CODE_CLASS (TREE_CODE (node)) == 't')
 290     type = node, is_type = 1;
 291
 292   attributes = chainon (prefix_attributes, attributes);
 293
 294   for (a = attributes; a; a = TREE_CHAIN (a))
 295     {
 296       tree name = TREE_PURPOSE (a);
 297       tree args = TREE_VALUE (a);
 298       int i;
 299       enum attrs id;
 300
 301       for (i = 0; i < attrtab_idx; i++)
 302         if (attrtab[i].name == name)
 303           break;
 304
 305       if (i == attrtab_idx)
 306         {
 307           if (! valid_machine_attribute (name, args, decl, type))
 308             warning ("`%s' attribute directive ignored",
 309                      IDENTIFIER_POINTER (name));
 310           continue;
 311         }
 312       else if (attrtab[i].decl_req && decl == 0)
 313         {
 314           warning ("`%s' attribute does not apply to types",
 315                    IDENTIFIER_POINTER (name));
 316           continue;
 317         }
 318       else if (list_length (args) < attrtab[i].min
 319                || list_length (args) > attrtab[i].max)
 320         {
 321           error ("wrong number of arguments specified for `%s' attribute",
 322                  IDENTIFIER_POINTER (name));
 323           continue;
 324         }
 325
 326       id = attrtab[i].id;
 327       switch (id)
 328         {
 329         case A_PACKED:
 330           if (decl == 0)
 331             TYPE_PACKED (type) = 1;
 332           else if (TREE_CODE (decl) == FIELD_DECL)
 333             DECL_PACKED (decl) = 1;
 334           /* We can't set DECL_PACKED for a VAR_DECL, because the bit is
 335              used for DECL_REGISTER.  It wouldn't mean anything anyway.  */
 336           else
 337             warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
 338           break;
 339
 340         case A_NOCOMMON:
 341           if (TREE_CODE (decl) == VAR_DECL)
 342             DECL_COMMON (decl) = 0;
 343           else
 344             warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
 345           break;
 346
 347         case A_NORETURN:
 348           if (TREE_CODE (decl) == FUNCTION_DECL)
 349             TREE_THIS_VOLATILE (decl) = 1;
 350           else if (TREE_CODE (type) == POINTER_TYPE
 351                    && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
 352             TREE_TYPE (decl) = type
 353               = build_pointer_type
 354                 (build_type_variant (TREE_TYPE (type),
 355                                      TREE_READONLY (TREE_TYPE (type)), 1));
 356           else
 357             warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
 358           break;
 359
 360         case A_UNUSED:
 361           if (TREE_CODE (decl) == PARM_DECL || TREE_CODE (decl) == VAR_DECL
 362               || TREE_CODE (decl) == FUNCTION_DECL)
 363             TREE_USED (decl) = 1;
 364           else
 365             warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
 366           break;
 367
 368         case A_CONST:
 369           if (TREE_CODE (decl) == FUNCTION_DECL)
 370             TREE_READONLY (decl) = 1;
 371           else if (TREE_CODE (type) == POINTER_TYPE
 372                    && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
 373             TREE_TYPE (decl) = type
 374               = build_pointer_type
 375                 (build_type_variant (TREE_TYPE (type), 1,
 376                                      TREE_THIS_VOLATILE (TREE_TYPE (type))));
 377           else
 378             warning ( "`%s' attribute ignored", IDENTIFIER_POINTER (name));
 379           break;
 380
 381         case A_T_UNION:
 382           if (decl != 0 && TREE_CODE (decl) == PARM_DECL
 383               && TREE_CODE (type) == UNION_TYPE
 384               && TYPE_MODE (type) == DECL_MODE (TYPE_FIELDS (type)))
 385             DECL_TRANSPARENT_UNION (decl) = 1;
 386           else if (is_type
 387                    && TREE_CODE (type) == UNION_TYPE
 388                    && TYPE_MODE (type) == DECL_MODE (TYPE_FIELDS (type)))
 389             TYPE_TRANSPARENT_UNION (type) = 1;
 390           else
 391             warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
 392           break;
 393
 394         case A_CONSTRUCTOR:
 395           if (TREE_CODE (decl) == FUNCTION_DECL
 396               && TREE_CODE (type) == FUNCTION_TYPE
 397               && decl_function_context (decl) == 0)
 398             DECL_STATIC_CONSTRUCTOR (decl) = 1;
 399           else
 400             warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
 401           break;
 402
 403         case A_DESTRUCTOR:
 404           if (TREE_CODE (decl) == FUNCTION_DECL
 405               && TREE_CODE (type) == FUNCTION_TYPE
 406               && decl_function_context (decl) == 0)
 407             DECL_STATIC_DESTRUCTOR (decl) = 1;
 408           else
 409             warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
 410           break;
 411
 412         case A_MODE:
 413           if (TREE_CODE (TREE_VALUE (args)) != IDENTIFIER_NODE)
 414             warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
 415           else
 416             {
 417               int j;
 418               char *p = IDENTIFIER_POINTER (TREE_VALUE (args));
 419               int len = strlen (p);
 420               enum machine_mode mode = VOIDmode;
 421               tree typefm;
 422
 423               if (len > 4 && p[0] == '_' && p[1] == '_'
 424                   && p[len - 1] == '_' && p[len - 2] == '_')
 425                 {
 426                   char *newp = (char *) alloca (len - 2);
 427
 428                   strcpy (newp, &p[2]);
 429                   newp[len - 4] = '\0';
 430                   p = newp;
 431                 }
 432
 433               /* Give this decl a type with the specified mode.
 434                  First check for the special modes.  */
 435               if (! strcmp (p, "byte"))
 436                 mode = byte_mode;
 437               else if (!strcmp (p, "word"))
 438                 mode = word_mode;
 439               else if (! strcmp (p, "pointer"))
 440                 mode = ptr_mode;
 441               else
 442                 for (j = 0; j < NUM_MACHINE_MODES; j++)
 443                   if (!strcmp (p, GET_MODE_NAME (j)))
 444                     mode = (enum machine_mode) j;
 445
 446               if (mode == VOIDmode)
 447                 error ("unknown machine mode `%s'", p);
 448               else if (0 == (typefm = type_for_mode (mode,
 449                                                      TREE_UNSIGNED (type))))
 450                 error ("no data type for mode `%s'", p);
 451               else
 452                 {
 453                   TREE_TYPE (decl) = type = typefm;
 454                   DECL_SIZE (decl) = 0;
 455                   layout_decl (decl, 0);
 456                 }
 457             }
 458           break;
 459
 460         case A_SECTION:
 461 #ifdef ASM_OUTPUT_SECTION_NAME
 462           if ((TREE_CODE (decl) == FUNCTION_DECL
 463                || TREE_CODE (decl) == VAR_DECL)
 464               && TREE_CODE (TREE_VALUE (args)) == STRING_CST)
 465             {
 466               if (TREE_CODE (decl) == VAR_DECL
 467                   && current_function_decl != NULL_TREE)
 468                 error_with_decl (decl,
 469                   "section attribute cannot be specified for local variables");
 470               /* The decl may have already been given a section attribute from
 471                  a previous declaration.  Ensure they match.  */
 472               else if (DECL_SECTION_NAME (decl) != NULL_TREE
 473                        && strcmp (TREE_STRING_POINTER (DECL_SECTION_NAME (decl)),
 474                                   TREE_STRING_POINTER (TREE_VALUE (args))) != 0)
 475                 error_with_decl (node,
 476                                  "section of `%s' conflicts with previous declaration");
 477               else
 478                 DECL_SECTION_NAME (decl) = TREE_VALUE (args);
 479             }
 480           else
 481             error_with_decl (node,
 482                            "section attribute not allowed for `%s'");
 483 #else
 484           error_with_decl (node,
 485                   "section attributes are not supported for this target");
 486 #endif
 487           break;
 488
 489         case A_ALIGNED:
 490           {
 491             tree align_expr
 492               = args ? TREE_VALUE (args) : size_int (BIGGEST_ALIGNMENT);
 493             int align;
 494
 495             /* Strip any NOPs of any kind.  */
 496             while (TREE_CODE (align_expr) == NOP_EXPR
 497                    || TREE_CODE (align_expr) == CONVERT_EXPR
 498                    || TREE_CODE (align_expr) == NON_LVALUE_EXPR)
 499               align_expr = TREE_OPERAND (align_expr, 0);
 500
 501             if (TREE_CODE (align_expr) != INTEGER_CST)
 502               {
 503                 error ("requested alignment is not a constant");
 504                 continue;
 505               }
 506
 507             align = TREE_INT_CST_LOW (align_expr) * BITS_PER_UNIT;
 508
 509             if (exact_log2 (align) == -1)
 510               error ("requested alignment is not a power of 2");
 511             else if (is_type)
 512               TYPE_ALIGN (TREE_TYPE (decl)) = align;
 513             else if (TREE_CODE (decl) != VAR_DECL
 514                      && TREE_CODE (decl) != FIELD_DECL)
 515               error_with_decl (decl,
 516                                "alignment may not be specified for `%s'");
 517             else
 518               DECL_ALIGN (decl) = align;
 519           }
 520           break;
 521
 522         case A_FORMAT:
 523           {
 524             tree format_type = TREE_VALUE (args);
 525             tree format_num_expr = TREE_VALUE (TREE_CHAIN (args));
 526             tree first_arg_num_expr
 527               = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (args)));
 528             int format_num;
 529             int first_arg_num;
 530             int is_scan;
 531             tree argument;
 532             int arg_num;
 533
 534             if (TREE_CODE (decl) != FUNCTION_DECL)
 535               {
 536                 error_with_decl (decl,
 537                          "argument format specified for non-function `%s'");
 538                 continue;
 539               }
 540
 541             if (TREE_CODE (format_type) == IDENTIFIER_NODE
 542                 && (!strcmp (IDENTIFIER_POINTER (format_type), "printf")
 543                     || !strcmp (IDENTIFIER_POINTER (format_type),
 544                                 "__printf__")))
 545               is_scan = 0;
 546             else if (TREE_CODE (format_type) == IDENTIFIER_NODE
 547                      && (!strcmp (IDENTIFIER_POINTER (format_type), "scanf")
 548                          || !strcmp (IDENTIFIER_POINTER (format_type),
 549                                      "__scanf__")))
 550               is_scan = 1;
 551             else
 552               {
 553                 error ("unrecognized format specifier for `%s'");
 554                 continue;
 555               }
 556
 557             /* Strip any conversions from the string index and first arg number
 558                and verify they are constants.  */
 559             while (TREE_CODE (format_num_expr) == NOP_EXPR
 560                    || TREE_CODE (format_num_expr) == CONVERT_EXPR
 561                    || TREE_CODE (format_num_expr) == NON_LVALUE_EXPR)
 562               format_num_expr = TREE_OPERAND (format_num_expr, 0);
 563
 564             while (TREE_CODE (first_arg_num_expr) == NOP_EXPR
 565                    || TREE_CODE (first_arg_num_expr) == CONVERT_EXPR
 566                    || TREE_CODE (first_arg_num_expr) == NON_LVALUE_EXPR)
 567               first_arg_num_expr = TREE_OPERAND (first_arg_num_expr, 0);
 568
 569             if (TREE_CODE (format_num_expr) != INTEGER_CST
 570                 || TREE_CODE (first_arg_num_expr) != INTEGER_CST)
 571               {
 572                 error ("format string has non-constant operand number");
 573                 continue;
 574               }
 575
 576             format_num = TREE_INT_CST_LOW (format_num_expr);
 577             first_arg_num = TREE_INT_CST_LOW (first_arg_num_expr);
 578             if (first_arg_num != 0 && first_arg_num <= format_num)
 579               {
 580                 error ("format string arg follows the args to be formatted");
 581                 continue;
 582               }
 583
 584             /* If a parameter list is specified, verify that the format_num
 585                argument is actually a string, in case the format attribute
 586                is in error.  */
 587             argument = TYPE_ARG_TYPES (type);
 588             if (argument)
 589               {
 590                 for (arg_num = 1; ; ++arg_num)
 591                   {
 592                     if (argument == 0 || arg_num == format_num)
 593                       break;
 594                     argument = TREE_CHAIN (argument);
 595                   }
 596                 if (! argument
 597                     || TREE_CODE (TREE_VALUE (argument)) != POINTER_TYPE
 598                   || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (argument)))
 599                       != char_type_node))
 600                   {
 601                     error ("format string arg not a string type");
 602                     continue;
 603                   }
 604                 if (first_arg_num != 0)
 605                   {
 606                     /* Verify that first_arg_num points to the last arg,
 607                        the ... */
 608                     while (argument)
 609                       arg_num++, argument = TREE_CHAIN (argument);
 610                   if (arg_num != first_arg_num)
 611                     {
 612                       error ("args to be formatted is not ...");
 613                       continue;
 614                     }
 615                   }
 616               }
 617
 618             record_function_format (DECL_NAME (decl),
 619                                     DECL_ASSEMBLER_NAME (decl),
 620                                     is_scan, format_num, first_arg_num);
 621             break;
 622           }
 623
 624         case A_WEAK:
 625           declare_weak (decl);
 626           break;
 627
 628         case A_ALIAS:
 629           if ((TREE_CODE (decl) == FUNCTION_DECL && DECL_INITIAL (decl))
 630               || TREE_CODE (decl) != FUNCTION_DECL && ! DECL_EXTERNAL (decl))
 631             error_with_decl (decl,
 632                              "`%s' defined both normally and as an alias");
 633           else if (decl_function_context (decl) == 0)
 634             {
 635               tree id = get_identifier (TREE_STRING_POINTER
 636                                         (TREE_VALUE (args)));
 637               if (TREE_CODE (decl) == FUNCTION_DECL)
 638                 DECL_INITIAL (decl) = error_mark_node;
 639               else
 640                 DECL_EXTERNAL (decl) = 0;
 641               assemble_alias (decl, id);
 642             }
 643           else
 644             warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
 645           break;
 646         }
 647     }
 648 }
 649 \f
 650 /* Check a printf/fprintf/sprintf/scanf/fscanf/sscanf format against
 651    a parameter list.  */
 652
 653 #define T_I     &integer_type_node
 654 #define T_L     &long_integer_type_node
 655 #define T_LL    &long_long_integer_type_node
 656 #define T_S     &short_integer_type_node
 657 #define T_UI    &unsigned_type_node
 658 #define T_UL    &long_unsigned_type_node
 659 #define T_ULL   &long_long_unsigned_type_node
 660 #define T_US    &short_unsigned_type_node
 661 #define T_F     &float_type_node
 662 #define T_D     &double_type_node
 663 #define T_LD    &long_double_type_node
 664 #define T_C     &char_type_node
 665 #define T_V     &void_type_node
 666 #define T_W     &wchar_type_node
 667 #define T_ST    &sizetype
 668
 669 typedef struct {
 670   char *format_chars;
 671   int pointer_count;
 672   /* Type of argument if no length modifier is used.  */
 673   tree *nolen;
 674   /* Type of argument if length modifier for shortening is used.
 675      If NULL, then this modifier is not allowed.  */
 676   tree *hlen;
 677   /* Type of argument if length modifier `l' is used.
 678      If NULL, then this modifier is not allowed.  */
 679   tree *llen;
 680   /* Type of argument if length modifier `q' or `ll' is used.
 681      If NULL, then this modifier is not allowed.  */
 682   tree *qlen;
 683   /* Type of argument if length modifier `L' is used.
 684      If NULL, then this modifier is not allowed.  */
 685   tree *bigllen;
 686   /* List of other modifier characters allowed with these options.  */
 687   char *flag_chars;
 688 } format_char_info;
 689
 690 static format_char_info print_char_table[] = {
 691   { "di",       0,      T_I,    T_I,    T_L,    T_LL,   T_LL,   "-wp0 +"        },
 692   { "oxX",      0,      T_UI,   T_UI,   T_UL,   T_ULL,  T_ULL,  "-wp0#"         },
 693   { "u",        0,      T_UI,   T_UI,   T_UL,   T_ULL,  T_ULL,  "-wp0"          },
 694 /* Two GNU extensions.  */
 695   { "Z",        0,      T_ST,   NULL,   NULL,   NULL,   NULL,   "-wp0"          },
 696   { "m",        0,      T_UI,   T_UI,   T_UL,   NULL,   NULL,   "-wp"           },
 697   { "feEgG",    0,      T_D,    NULL,   NULL,   NULL,   T_LD,   "-wp0 +#"       },
 698   { "c",        0,      T_I,    NULL,   T_W,    NULL,   NULL,   "-w"            },
 699   { "C",        0,      T_W,    NULL,   NULL,   NULL,   NULL,   "-w"            },
 700   { "s",        1,      T_C,    NULL,   T_W,    NULL,   NULL,   "-wp"           },
 701   { "S",        1,      T_W,    NULL,   NULL,   NULL,   NULL,   "-wp"           },
 702   { "p",        1,      T_V,    NULL,   NULL,   NULL,   NULL,   "-w"            },
 703   { "n",        1,      T_I,    T_S,    T_L,    T_LL,   NULL,   ""              },
 704   { NULL }
 705 };
 706
 707 static format_char_info scan_char_table[] = {
 708   { "di",       1,      T_I,    T_S,    T_L,    T_LL,   T_LL,   "*"     },
 709   { "ouxX",     1,      T_UI,   T_US,   T_UL,   T_ULL,  T_ULL,  "*"     },
 710   { "efgEG",    1,      T_F,    NULL,   T_D,    NULL,   T_LD,   "*"     },
 711   { "sc",       1,      T_C,    NULL,   T_W,    NULL,   NULL,   "*a"    },
 712   { "[",        1,      T_C,    NULL,   NULL,   NULL,   NULL,   "*a"    },
 713   { "C",        1,      T_W,    NULL,   NULL,   NULL,   NULL,   "*"     },
 714   { "S",        1,      T_W,    NULL,   NULL,   NULL,   NULL,   "*"     },
 715   { "p",        2,      T_V,    NULL,   NULL,   NULL,   NULL,   "*"     },
 716   { "n",        1,      T_I,    T_S,    T_L,    T_LL,   NULL,   ""      },
 717   { NULL }
 718 };
 719
 720 typedef struct function_format_info {
 721   struct function_format_info *next;  /* next structure on the list */
 722   tree name;                    /* identifier such as "printf" */
 723   tree assembler_name;          /* optional mangled identifier (for C++) */
 724   int is_scan;                  /* TRUE if *scanf */
 725   int format_num;               /* number of format argument */
 726   int first_arg_num;            /* number of first arg (zero for varargs) */
 727 } function_format_info;
 728
 729 static function_format_info *function_format_list = NULL;
 730
 731 static void check_format_info PROTO((function_format_info *, tree));
 732
 733 /* Initialize the table of functions to perform format checking on.
 734    The ANSI functions are always checked (whether <stdio.h> is
 735    included or not), since it is common to call printf without
 736    including <stdio.h>.  There shouldn't be a problem with this,
 737    since ANSI reserves these function names whether you include the
 738    header file or not.  In any case, the checking is harmless.  */
 739
 740 void
 741 init_function_format_info ()
 742 {
 743   record_function_format (get_identifier ("printf"), NULL_TREE, 0, 1, 2);
 744   record_function_format (get_identifier ("fprintf"), NULL_TREE, 0, 2, 3);
 745   record_function_format (get_identifier ("sprintf"), NULL_TREE, 0, 2, 3);
 746   record_function_format (get_identifier ("scanf"), NULL_TREE, 1, 1, 2);
 747   record_function_format (get_identifier ("fscanf"), NULL_TREE, 1, 2, 3);
 748   record_function_format (get_identifier ("sscanf"), NULL_TREE, 1, 2, 3);
 749   record_function_format (get_identifier ("vprintf"), NULL_TREE, 0, 1, 0);
 750   record_function_format (get_identifier ("vfprintf"), NULL_TREE, 0, 2, 0);
 751   record_function_format (get_identifier ("vsprintf"), NULL_TREE, 0, 2, 0);
 752 }
 753
 754 /* Record information for argument format checking.  FUNCTION_IDENT is
 755    the identifier node for the name of the function to check (its decl
 756    need not exist yet).  IS_SCAN is true for scanf-type format checking;
 757    false indicates printf-style format checking.  FORMAT_NUM is the number
 758    of the argument which is the format control string (starting from 1).
 759    FIRST_ARG_NUM is the number of the first actual argument to check
 760    against teh format string, or zero if no checking is not be done
 761    (e.g. for varargs such as vfprintf).  */
 762
 763 void
 764 record_function_format (name, assembler_name, is_scan,
 765                         format_num, first_arg_num)
 766       tree name;
 767       tree assembler_name;
 768       int is_scan;
 769       int format_num;
 770       int first_arg_num;
 771 {
 772   function_format_info *info;
 773
 774   /* Re-use existing structure if it's there.  */
 775
 776   for (info = function_format_list; info; info = info->next)
 777     {
 778       if (info->name == name && info->assembler_name == assembler_name)
 779         break;
 780     }
 781   if (! info)
 782     {
 783       info = (function_format_info *) xmalloc (sizeof (function_format_info));
 784       info->next = function_format_list;
 785       function_format_list = info;
 786
 787       info->name = name;
 788       info->assembler_name = assembler_name;
 789     }
 790
 791   info->is_scan = is_scan;
 792   info->format_num = format_num;
 793   info->first_arg_num = first_arg_num;
 794 }
 795
 796 static char     tfaff[] = "too few arguments for format";
 797 \f
 798 /* Check the argument list of a call to printf, scanf, etc.
 799    NAME is the function identifier.
 800    ASSEMBLER_NAME is the function's assembler identifier.
 801    (Either NAME or ASSEMBLER_NAME, but not both, may be NULL_TREE.)
 802    PARAMS is the list of argument values.  */
 803
 804 void
 805 check_function_format (name, assembler_name, params)
 806      tree name;
 807      tree assembler_name;
 808      tree params;
 809 {
 810   function_format_info *info;
 811
 812   /* See if this function is a format function.  */
 813   for (info = function_format_list; info; info = info->next)
 814     {
 815       if (info->assembler_name
 816           ? (info->assembler_name == assembler_name)
 817           : (info->name == name))
 818         {
 819           /* Yup; check it.  */
 820           check_format_info (info, params);
 821           break;
 822         }
 823     }
 824 }
 825
 826 /* Check the argument list of a call to printf, scanf, etc.
 827    INFO points to the function_format_info structure.
 828    PARAMS is the list of argument values.  */
 829
 830 static void
 831 check_format_info (info, params)
 832      function_format_info *info;
 833      tree params;
 834 {
 835   int i;
 836   int arg_num;
 837   int suppressed, wide, precise;
 838   int length_char;
 839   int format_char;
 840   int format_length;
 841   tree format_tree;
 842   tree cur_param;
 843   tree cur_type;
 844   tree wanted_type;
 845   tree first_fillin_param;
 846   char *format_chars;
 847   format_char_info *fci;
 848   static char message[132];
 849   char flag_chars[8];
 850   int has_operand_number = 0;
 851
 852   /* Skip to format argument.  If the argument isn't available, there's
 853      no work for us to do; prototype checking will catch the problem.  */
 854   for (arg_num = 1; ; ++arg_num)
 855     {
 856       if (params == 0)
 857         return;
 858       if (arg_num == info->format_num)
 859         break;
 860       params = TREE_CHAIN (params);
 861     }
 862   format_tree = TREE_VALUE (params);
 863   params = TREE_CHAIN (params);
 864   if (format_tree == 0)
 865     return;
 866   /* We can only check the format if it's a string constant.  */
 867   while (TREE_CODE (format_tree) == NOP_EXPR)
 868     format_tree = TREE_OPERAND (format_tree, 0); /* strip coercion */
 869   if (format_tree == null_pointer_node)
 870     {
 871       warning ("null format string");
 872       return;
 873     }
 874   if (TREE_CODE (format_tree) != ADDR_EXPR)
 875     return;
 876   format_tree = TREE_OPERAND (format_tree, 0);
 877   if (TREE_CODE (format_tree) != STRING_CST)
 878     return;
 879   format_chars = TREE_STRING_POINTER (format_tree);
 880   format_length = TREE_STRING_LENGTH (format_tree);
 881   if (format_length <= 1)
 882     warning ("zero-length format string");
 883   if (format_chars[--format_length] != 0)
 884     {
 885       warning ("unterminated format string");
 886       return;
 887     }
 888   /* Skip to first argument to check.  */
 889   while (arg_num + 1 < info->first_arg_num)
 890     {
 891       if (params == 0)
 892         return;
 893       params = TREE_CHAIN (params);
 894       ++arg_num;
 895     }
 896
 897   first_fillin_param = params;
 898   while (1)
 899     {
 900       int aflag;
 901       if (*format_chars == 0)
 902         {
 903           if (format_chars - TREE_STRING_POINTER (format_tree) != format_length)
 904             warning ("embedded `\\0' in format");
 905           if (info->first_arg_num != 0 && params != 0 && ! has_operand_number)
 906             warning ("too many arguments for format");
 907           return;
 908         }
 909       if (*format_chars++ != '%')
 910         continue;
 911       if (*format_chars == 0)
 912         {
 913           warning ("spurious trailing `%%' in format");
 914           continue;
 915         }
 916       if (*format_chars == '%')
 917         {
 918           ++format_chars;
 919           continue;
 920         }
 921       flag_chars[0] = 0;
 922       suppressed = wide = precise = FALSE;
 923       if (info->is_scan)
 924         {
 925           suppressed = *format_chars == '*';
 926           if (suppressed)
 927             ++format_chars;
 928           while (isdigit (*format_chars))
 929             ++format_chars;
 930         }
 931       else
 932         {
 933           /* See if we have a number followed by a dollar sign.  If we do,
 934              it is an operand number, so set PARAMS to that operand.  */
 935           if (*format_chars >= '0' && *format_chars <= '9')
 936             {
 937               char *p = format_chars;
 938
 939               while (*p >= '0' && *p++ <= '9')
 940                 ;
 941
 942               if (*p == '$')
 943                 {
 944                   int opnum = atoi (format_chars);
 945
 946                   params = first_fillin_param;
 947                   format_chars = p + 1;
 948                   has_operand_number = 1;
 949
 950                   for (i = 1; i < opnum && params != 0; i++)
 951                     params = TREE_CHAIN (params);
 952
 953                   if (opnum == 0 || params == 0)
 954                     {
 955                       warning ("operand number out of range in format");
 956                       return;
 957                     }
 958                 }
 959             }
 960
 961           while (*format_chars != 0 && index (" +#0-", *format_chars) != 0)
 962             {
 963               if (index (flag_chars, *format_chars) != 0)
 964                 {
 965                   sprintf (message, "repeated `%c' flag in format",
 966                            *format_chars);
 967                   warning (message);
 968                 }
 969               i = strlen (flag_chars);
 970               flag_chars[i++] = *format_chars++;
 971               flag_chars[i] = 0;
 972             }
 973           /* "If the space and + flags both appear,
 974              the space flag will be ignored."  */
 975           if (index (flag_chars, ' ') != 0
 976               && index (flag_chars, '+') != 0)
 977             warning ("use of both ` ' and `+' flags in format");
 978           /* "If the 0 and - flags both appear,
 979              the 0 flag will be ignored."  */
 980           if (index (flag_chars, '0') != 0
 981               && index (flag_chars, '-') != 0)
 982             warning ("use of both `0' and `-' flags in format");
 983           if (*format_chars == '*')
 984             {
 985               wide = TRUE;
 986               /* "...a field width...may be indicated by an asterisk.
 987                  In this case, an int argument supplies the field width..."  */
 988               ++format_chars;
 989               if (params == 0)
 990                 {
 991                   warning (tfaff);
 992                   return;
 993                 }
 994               if (info->first_arg_num != 0)
 995                 {
 996                   cur_param = TREE_VALUE (params);
 997                   params = TREE_CHAIN (params);
 998                   ++arg_num;
 999                   /* size_t is generally not valid here.
1000                      It will work on most machines, because size_t and int
1001                      have the same mode.  But might as well warn anyway,
1002                      since it will fail on other machines.  */
1003                   if ((TYPE_MAIN_VARIANT (TREE_TYPE (cur_param))
1004                        != integer_type_node)
1005                       &&
1006                       (TYPE_MAIN_VARIANT (TREE_TYPE (cur_param))
1007                        != unsigned_type_node))
1008                     {
1009                       sprintf (message,
1010                                "field width is not type int (arg %d)",
1011                                arg_num);
1012                       warning (message);
1013                     }
1014                 }
1015             }
1016           else
1017             {
1018               while (isdigit (*format_chars))
1019                 {
1020                   wide = TRUE;
1021                   ++format_chars;
1022                 }
1023             }
1024           if (*format_chars == '.')
1025             {
1026               precise = TRUE;
1027               ++format_chars;
1028               if (*format_chars != '*' && !isdigit (*format_chars))
1029                 warning ("`.' not followed by `*' or digit in format");
1030               /* "...a...precision...may be indicated by an asterisk.
1031                  In this case, an int argument supplies the...precision."  */
1032               if (*format_chars == '*')
1033                 {
1034                   if (info->first_arg_num != 0)
1035                     {
1036                       ++format_chars;
1037                       if (params == 0)
1038                         {
1039                           warning (tfaff);
1040                           return;
1041                         }
1042                       cur_param = TREE_VALUE (params);
1043                       params = TREE_CHAIN (params);
1044                       ++arg_num;
1045                       if (TYPE_MAIN_VARIANT (TREE_TYPE (cur_param))
1046                           != integer_type_node)
1047                         {
1048                           sprintf (message,
1049                                    "field width is not type int (arg %d)",
1050                                    arg_num);
1051                           warning (message);
1052                         }
1053                     }
1054                 }
1055               else
1056                 {
1057                   while (isdigit (*format_chars))
1058                     ++format_chars;
1059                 }
1060             }
1061         }
1062       if (*format_chars == 'h' || *format_chars == 'l' || *format_chars == 'q' ||
1063           *format_chars == 'L')
1064         length_char = *format_chars++;
1065       else
1066         length_char = 0;
1067       if (length_char == 'l' && *format_chars == 'l')
1068         length_char = 'q', format_chars++;
1069       aflag = 0;
1070       if (*format_chars == 'a')
1071         {
1072           aflag = 1;
1073           format_chars++;
1074         }
1075       if (suppressed && length_char != 0)
1076         {
1077           sprintf (message,
1078                    "use of `*' and `%c' together in format",
1079                    length_char);
1080           warning (message);
1081         }
1082       format_char = *format_chars;
1083       if (format_char == 0)
1084         {
1085           warning ("conversion lacks type at end of format");
1086           continue;
1087         }
1088       format_chars++;
1089       fci = info->is_scan ? scan_char_table : print_char_table;
1090       while (fci->format_chars != 0
1091              && index (fci->format_chars, format_char) == 0)
1092           ++fci;
1093       if (fci->format_chars == 0)
1094         {
1095           if (format_char >= 040 && format_char < 0177)
1096             sprintf (message,
1097                      "unknown conversion type character `%c' in format",
1098                      format_char);
1099           else
1100             sprintf (message,
1101                      "unknown conversion type character 0x%x in format",
1102                      format_char);
1103           warning (message);
1104           continue;
1105         }
1106       if (wide && index (fci->flag_chars, 'w') == 0)
1107         {
1108           sprintf (message, "width used with `%c' format",
1109                    format_char);
1110           warning (message);
1111         }
1112       if (precise && index (fci->flag_chars, 'p') == 0)
1113         {
1114           sprintf (message, "precision used with `%c' format",
1115                    format_char);
1116           warning (message);
1117         }
1118       if (aflag && index (fci->flag_chars, 'a') == 0)
1119         {
1120           sprintf (message, "`a' flag used with `%c' format",
1121                    format_char);
1122           warning (message);
1123         }
1124       if (info->is_scan && format_char == '[')
1125         {
1126           /* Skip over scan set, in case it happens to have '%' in it.  */
1127           if (*format_chars == '^')
1128             ++format_chars;
1129           /* Find closing bracket; if one is hit immediately, then
1130              it's part of the scan set rather than a terminator.  */
1131           if (*format_chars == ']')
1132             ++format_chars;
1133           while (*format_chars && *format_chars != ']')
1134             ++format_chars;
1135           if (*format_chars != ']')
1136               /* The end of the format string was reached.  */
1137               warning ("no closing `]' for `%%[' format");
1138         }
1139       if (suppressed)
1140         {
1141           if (index (fci->flag_chars, '*') == 0)
1142             {
1143               sprintf (message,
1144                        "suppression of `%c' conversion in format",
1145                        format_char);
1146               warning (message);
1147             }
1148           continue;
1149         }
1150       for (i = 0; flag_chars[i] != 0; ++i)
1151         {
1152           if (index (fci->flag_chars, flag_chars[i]) == 0)
1153             {
1154               sprintf (message, "flag `%c' used with type `%c'",
1155                        flag_chars[i], format_char);
1156               warning (message);
1157             }
1158         }
1159       if (precise && index (flag_chars, '0') != 0
1160           && (format_char == 'd' || format_char == 'i'
1161               || format_char == 'o' || format_char == 'u'
1162               || format_char == 'x' || format_char == 'x'))
1163         {
1164           sprintf (message,
1165                    "precision and `0' flag not both allowed with `%c' format",
1166                    format_char);
1167           warning (message);
1168         }
1169       switch (length_char)
1170         {
1171         default: wanted_type = fci->nolen ? *(fci->nolen) : 0; break;
1172         case 'h': wanted_type = fci->hlen ? *(fci->hlen) : 0; break;
1173         case 'l': wanted_type = fci->llen ? *(fci->llen) : 0; break;
1174         case 'q': wanted_type = fci->qlen ? *(fci->qlen) : 0; break;
1175         case 'L': wanted_type = fci->bigllen ? *(fci->bigllen) : 0; break;
1176         }
1177       if (wanted_type == 0)
1178         {
1179           sprintf (message,
1180                    "use of `%c' length character with `%c' type character",
1181                    length_char, format_char);
1182           warning (message);
1183         }
1184
1185       /*
1186        ** XXX -- should kvetch about stuff such as
1187        **       {
1188        **               const int       i;
1189        **
1190        **               scanf ("%d", &i);
1191        **       }
1192        */
1193
1194       /* Finally. . .check type of argument against desired type!  */
1195       if (info->first_arg_num == 0)
1196         continue;
1197       if (params == 0)
1198         {
1199           warning (tfaff);
1200           return;
1201         }
1202       cur_param = TREE_VALUE (params);
1203       params = TREE_CHAIN (params);
1204       ++arg_num;
1205       cur_type = TREE_TYPE (cur_param);
1206
1207       /* Check the types of any additional pointer arguments
1208          that precede the "real" argument.  */
1209       for (i = 0; i < fci->pointer_count; ++i)
1210         {
1211           if (TREE_CODE (cur_type) == POINTER_TYPE)
1212             {
1213               cur_type = TREE_TYPE (cur_type);
1214               continue;
1215             }
1216           sprintf (message,
1217                    "format argument is not a %s (arg %d)",
1218                    ((fci->pointer_count == 1) ? "pointer" : "pointer to a pointer"),
1219                    arg_num);
1220           warning (message);
1221           break;
1222         }
1223
1224       /* Check the type of the "real" argument, if there's a type we want.  */
1225       if (i == fci->pointer_count && wanted_type != 0
1226           && wanted_type != TYPE_MAIN_VARIANT (cur_type)
1227           /* If we want `void *', allow any pointer type.
1228              (Anything else would already have got a warning.)  */
1229           && ! (wanted_type == void_type_node
1230                 && fci->pointer_count > 0)
1231           /* Don't warn about differences merely in signedness.  */
1232           && !(TREE_CODE (wanted_type) == INTEGER_TYPE
1233                && TREE_CODE (TYPE_MAIN_VARIANT (cur_type)) == INTEGER_TYPE
1234                && (TREE_UNSIGNED (wanted_type)
1235                    ? wanted_type == (cur_type = unsigned_type (cur_type))
1236                    : wanted_type == (cur_type = signed_type (cur_type))))
1237           /* Likewise, "signed char", "unsigned char" and "char" are
1238              equivalent but the above test won't consider them equivalent.  */
1239           && ! (wanted_type == char_type_node
1240                 && (TYPE_MAIN_VARIANT (cur_type) == signed_char_type_node
1241                     || TYPE_MAIN_VARIANT (cur_type) == unsigned_char_type_node)))
1242         {
1243           register char *this;
1244           register char *that;
1245
1246           this = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (wanted_type)));
1247           that = 0;
1248           if (TREE_CODE (cur_type) != ERROR_MARK
1249               && TYPE_NAME (cur_type) != 0
1250               && TREE_CODE (cur_type) != INTEGER_TYPE
1251               && !(TREE_CODE (cur_type) == POINTER_TYPE
1252                    && TREE_CODE (TREE_TYPE (cur_type)) == INTEGER_TYPE))
1253             {
1254               if (TREE_CODE (TYPE_NAME (cur_type)) == TYPE_DECL
1255                   && DECL_NAME (TYPE_NAME (cur_type)) != 0)
1256                 that = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (cur_type)));
1257               else
1258                 that = IDENTIFIER_POINTER (TYPE_NAME (cur_type));
1259             }
1260
1261           /* A nameless type can't possibly match what the format wants.
1262              So there will be a warning for it.
1263              Make up a string to describe vaguely what it is.  */
1264           if (that == 0)
1265             {
1266               if (TREE_CODE (cur_type) == POINTER_TYPE)
1267                 that = "pointer";
1268               else
1269                 that = "different type";
1270             }
1271
1272           /* Make the warning better in case of mismatch of int vs long.  */
1273           if (TREE_CODE (cur_type) == INTEGER_TYPE
1274               && TREE_CODE (wanted_type) == INTEGER_TYPE
1275               && TYPE_PRECISION (cur_type) == TYPE_PRECISION (wanted_type)
1276               && TYPE_NAME (cur_type) != 0
1277               && TREE_CODE (TYPE_NAME (cur_type)) == TYPE_DECL)
1278             that = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (cur_type)));
1279
1280           if (strcmp (this, that) != 0)
1281             {
1282               sprintf (message, "%s format, %s arg (arg %d)",
1283                         this, that, arg_num);
1284               warning (message);
1285             }
1286         }
1287     }
1288 }
1289 \f
1290 /* Print a warning if a constant expression had overflow in folding.
1291    Invoke this function on every expression that the language
1292    requires to be a constant expression.
1293    Note the ANSI C standard says it is erroneous for a
1294    constant expression to overflow.  */
1295
1296 void
1297 constant_expression_warning (value)
1298      tree value;
1299 {
1300   if ((TREE_CODE (value) == INTEGER_CST || TREE_CODE (value) == REAL_CST
1301        || TREE_CODE (value) == COMPLEX_CST)
1302       && TREE_CONSTANT_OVERFLOW (value) && pedantic)
1303     pedwarn ("overflow in constant expression");
1304 }
1305
1306 /* Print a warning if an expression had overflow in folding.
1307    Invoke this function on every expression that
1308    (1) appears in the source code, and
1309    (2) might be a constant expression that overflowed, and
1310    (3) is not already checked by convert_and_check;
1311    however, do not invoke this function on operands of explicit casts.  */
1312
1313 void
1314 overflow_warning (value)
1315      tree value;
1316 {
1317   if ((TREE_CODE (value) == INTEGER_CST
1318        || (TREE_CODE (value) == COMPLEX_CST
1319            && TREE_CODE (TREE_REALPART (value)) == INTEGER_CST))
1320       && TREE_OVERFLOW (value))
1321     {
1322       TREE_OVERFLOW (value) = 0;
1323       warning ("integer overflow in expression");
1324     }
1325   else if ((TREE_CODE (value) == REAL_CST
1326             || (TREE_CODE (value) == COMPLEX_CST
1327                 && TREE_CODE (TREE_REALPART (value)) == REAL_CST))
1328            && TREE_OVERFLOW (value))
1329     {
1330       TREE_OVERFLOW (value) = 0;
1331       warning ("floating-pointer overflow in expression");
1332     }
1333 }
1334
1335 /* Print a warning if a large constant is truncated to unsigned,
1336    or if -Wconversion is used and a constant < 0 is converted to unsigned.
1337    Invoke this function on every expression that might be implicitly
1338    converted to an unsigned type.  */
1339
1340 void
1341 unsigned_conversion_warning (result, operand)
1342      tree result, operand;
1343 {
1344   if (TREE_CODE (operand) == INTEGER_CST
1345       && TREE_CODE (TREE_TYPE (result)) == INTEGER_TYPE
1346       && TREE_UNSIGNED (TREE_TYPE (result))
1347       && !int_fits_type_p (operand, TREE_TYPE (result)))
1348     {
1349       if (!int_fits_type_p (operand, signed_type (TREE_TYPE (result))))
1350         /* This detects cases like converting -129 or 256 to unsigned char.  */
1351         warning ("large integer implicitly truncated to unsigned type");
1352       else if (warn_conversion)
1353         warning ("negative integer implicitly converted to unsigned type");
1354     }
1355 }
1356
1357 /* Convert EXPR to TYPE, warning about conversion problems with constants.
1358    Invoke this function on every expression that is converted implicitly,
1359    i.e. because of language rules and not because of an explicit cast.  */
1360
1361 tree
1362 convert_and_check (type, expr)
1363      tree type, expr;
1364 {
1365   tree t = convert (type, expr);
1366   if (TREE_CODE (t) == INTEGER_CST)
1367     {
1368       if (TREE_OVERFLOW (t))
1369         {
1370           TREE_OVERFLOW (t) = 0;
1371
1372           /* Do not diagnose overflow in a constant expression merely
1373              because a conversion overflowed.  */
1374           TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (expr);
1375
1376           /* No warning for converting 0x80000000 to int.  */
1377           if (!(TREE_UNSIGNED (type) < TREE_UNSIGNED (TREE_TYPE (expr))
1378                 && TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
1379                 && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (expr))))
1380             /* If EXPR fits in the unsigned version of TYPE,
1381                don't warn unless pedantic.  */
1382             if (pedantic
1383                 || TREE_UNSIGNED (type)
1384                 || ! int_fits_type_p (expr, unsigned_type (type)))
1385               warning ("overflow in implicit constant conversion");
1386         }
1387       else
1388         unsigned_conversion_warning (t, expr);
1389     }
1390   return t;
1391 }
1392 \f
1393 void
1394 c_expand_expr_stmt (expr)
1395      tree expr;
1396 {
1397   /* Do default conversion if safe and possibly important,
1398      in case within ({...}).  */
1399   if ((TREE_CODE (TREE_TYPE (expr)) == ARRAY_TYPE && lvalue_p (expr))
1400       || TREE_CODE (TREE_TYPE (expr)) == FUNCTION_TYPE)
1401     expr = default_conversion (expr);
1402
1403   if (TREE_TYPE (expr) != error_mark_node
1404       && TYPE_SIZE (TREE_TYPE (expr)) == 0
1405       && TREE_CODE (TREE_TYPE (expr)) != ARRAY_TYPE)
1406     error ("expression statement has incomplete type");
1407
1408   expand_expr_stmt (expr);
1409 }
1410 \f
1411 /* Validate the expression after `case' and apply default promotions.  */
1412
1413 tree
1414 check_case_value (value)
1415      tree value;
1416 {
1417   if (value == NULL_TREE)
1418     return value;
1419
1420   /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
1421   STRIP_TYPE_NOPS (value);
1422
1423   if (TREE_CODE (value) != INTEGER_CST
1424       && value != error_mark_node)
1425     {
1426       error ("case label does not reduce to an integer constant");
1427       value = error_mark_node;
1428     }
1429   else
1430     /* Promote char or short to int.  */
1431     value = default_conversion (value);
1432
1433   constant_expression_warning (value);
1434
1435   return value;
1436 }
1437 \f
1438 /* Return an integer type with BITS bits of precision,
1439    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */
1440
1441 tree
1442 type_for_size (bits, unsignedp)
1443      unsigned bits;
1444      int unsignedp;
1445 {
1446   if (bits == TYPE_PRECISION (integer_type_node))
1447     return unsignedp ? unsigned_type_node : integer_type_node;
1448
1449   if (bits == TYPE_PRECISION (signed_char_type_node))
1450     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1451
1452   if (bits == TYPE_PRECISION (short_integer_type_node))
1453     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1454
1455   if (bits == TYPE_PRECISION (long_integer_type_node))
1456     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1457
1458   if (bits == TYPE_PRECISION (long_long_integer_type_node))
1459     return (unsignedp ? long_long_unsigned_type_node
1460             : long_long_integer_type_node);
1461
1462   if (bits <= TYPE_PRECISION (intQI_type_node))
1463     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1464
1465   if (bits <= TYPE_PRECISION (intHI_type_node))
1466     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1467
1468   if (bits <= TYPE_PRECISION (intSI_type_node))
1469     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1470
1471   if (bits <= TYPE_PRECISION (intDI_type_node))
1472     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1473
1474   return 0;
1475 }
1476
1477 /* Return a data type that has machine mode MODE.
1478    If the mode is an integer,
1479    then UNSIGNEDP selects between signed and unsigned types.  */
1480
1481 tree
1482 type_for_mode (mode, unsignedp)
1483      enum machine_mode mode;
1484      int unsignedp;
1485 {
1486   if (mode == TYPE_MODE (integer_type_node))
1487     return unsignedp ? unsigned_type_node : integer_type_node;
1488
1489   if (mode == TYPE_MODE (signed_char_type_node))
1490     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
1491
1492   if (mode == TYPE_MODE (short_integer_type_node))
1493     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
1494
1495   if (mode == TYPE_MODE (long_integer_type_node))
1496     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
1497
1498   if (mode == TYPE_MODE (long_long_integer_type_node))
1499     return unsignedp ? long_long_unsigned_type_node : long_long_integer_type_node;
1500
1501   if (mode == TYPE_MODE (intQI_type_node))
1502     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
1503
1504   if (mode == TYPE_MODE (intHI_type_node))
1505     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
1506
1507   if (mode == TYPE_MODE (intSI_type_node))
1508     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
1509
1510   if (mode == TYPE_MODE (intDI_type_node))
1511     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
1512
1513   if (mode == TYPE_MODE (float_type_node))
1514     return float_type_node;
1515
1516   if (mode == TYPE_MODE (double_type_node))
1517     return double_type_node;
1518
1519   if (mode == TYPE_MODE (long_double_type_node))
1520     return long_double_type_node;
1521
1522   if (mode == TYPE_MODE (build_pointer_type (char_type_node)))
1523     return build_pointer_type (char_type_node);
1524
1525   if (mode == TYPE_MODE (build_pointer_type (integer_type_node)))
1526     return build_pointer_type (integer_type_node);
1527
1528   return 0;
1529 }
1530 \f
1531 /* Return the minimum number of bits needed to represent VALUE in a
1532    signed or unsigned type, UNSIGNEDP says which.  */
1533
1534 int
1535 min_precision (value, unsignedp)
1536      tree value;
1537      int unsignedp;
1538 {
1539   int log;
1540
1541   /* If the value is negative, compute its negative minus 1.  The latter
1542      adjustment is because the absolute value of the largest negative value
1543      is one larger than the largest positive value.  This is equivalent to
1544      a bit-wise negation, so use that operation instead.  */
1545
1546   if (tree_int_cst_sgn (value) < 0)
1547     value = fold (build1 (BIT_NOT_EXPR, TREE_TYPE (value), value));
1548
1549   /* Return the number of bits needed, taking into account the fact
1550      that we need one more bit for a signed than unsigned type.  */
1551
1552   if (integer_zerop (value))
1553     log = 0;
1554   else if (TREE_INT_CST_HIGH (value) != 0)
1555     log = HOST_BITS_PER_WIDE_INT + floor_log2 (TREE_INT_CST_HIGH (value));
1556   else
1557     log = floor_log2 (TREE_INT_CST_LOW (value));
1558
1559   return log + 1 + ! unsignedp;
1560 }
1561 \f
1562 /* Print an error message for invalid operands to arith operation CODE.
1563    NOP_EXPR is used as a special case (see truthvalue_conversion).  */
1564
1565 void
1566 binary_op_error (code)
1567      enum tree_code code;
1568 {
1569   register char *opname = "unknown";
1570
1571   switch (code)
1572     {
1573     case NOP_EXPR:
1574       error ("invalid truth-value expression");
1575       return;
1576
1577     case PLUS_EXPR:
1578       opname = "+"; break;
1579     case MINUS_EXPR:
1580       opname = "-"; break;
1581     case MULT_EXPR:
1582       opname = "*"; break;
1583     case MAX_EXPR:
1584       opname = "max"; break;
1585     case MIN_EXPR:
1586       opname = "min"; break;
1587     case EQ_EXPR:
1588       opname = "=="; break;
1589     case NE_EXPR:
1590       opname = "!="; break;
1591     case LE_EXPR:
1592       opname = "<="; break;
1593     case GE_EXPR:
1594       opname = ">="; break;
1595     case LT_EXPR:
1596       opname = "<"; break;
1597     case GT_EXPR:
1598       opname = ">"; break;
1599     case LSHIFT_EXPR:
1600       opname = "<<"; break;
1601     case RSHIFT_EXPR:
1602       opname = ">>"; break;
1603     case TRUNC_MOD_EXPR:
1604     case FLOOR_MOD_EXPR:
1605       opname = "%"; break;
1606     case TRUNC_DIV_EXPR:
1607     case FLOOR_DIV_EXPR:
1608       opname = "/"; break;
1609     case BIT_AND_EXPR:
1610       opname = "&"; break;
1611     case BIT_IOR_EXPR:
1612       opname = "|"; break;
1613     case TRUTH_ANDIF_EXPR:
1614       opname = "&&"; break;
1615     case TRUTH_ORIF_EXPR:
1616       opname = "||"; break;
1617     case BIT_XOR_EXPR:
1618       opname = "^"; break;
1619     case LROTATE_EXPR:
1620     case RROTATE_EXPR:
1621       opname = "rotate"; break;
1622     }
1623   error ("invalid operands to binary %s", opname);
1624 }
1625 \f
1626 /* Subroutine of build_binary_op, used for comparison operations.
1627    See if the operands have both been converted from subword integer types
1628    and, if so, perhaps change them both back to their original type.
1629    This function is also responsible for converting the two operands
1630    to the proper common type for comparison.
1631
1632    The arguments of this function are all pointers to local variables
1633    of build_binary_op: OP0_PTR is &OP0, OP1_PTR is &OP1,
1634    RESTYPE_PTR is &RESULT_TYPE and RESCODE_PTR is &RESULTCODE.
1635
1636    If this function returns nonzero, it means that the comparison has
1637    a constant value.  What this function returns is an expression for
1638    that value.  */
1639
1640 tree
1641 shorten_compare (op0_ptr, op1_ptr, restype_ptr, rescode_ptr)
1642      tree *op0_ptr, *op1_ptr;
1643      tree *restype_ptr;
1644      enum tree_code *rescode_ptr;
1645 {
1646   register tree type;
1647   tree op0 = *op0_ptr;
1648   tree op1 = *op1_ptr;
1649   int unsignedp0, unsignedp1;
1650   int real1, real2;
1651   tree primop0, primop1;
1652   enum tree_code code = *rescode_ptr;
1653
1654   /* Throw away any conversions to wider types
1655      already present in the operands.  */
1656
1657   primop0 = get_narrower (op0, &unsignedp0);
1658   primop1 = get_narrower (op1, &unsignedp1);
1659
1660   /* Handle the case that OP0 does not *contain* a conversion
1661      but it *requires* conversion to FINAL_TYPE.  */
1662
1663   if (op0 == primop0 && TREE_TYPE (op0) != *restype_ptr)
1664     unsignedp0 = TREE_UNSIGNED (TREE_TYPE (op0));
1665   if (op1 == primop1 && TREE_TYPE (op1) != *restype_ptr)
1666     unsignedp1 = TREE_UNSIGNED (TREE_TYPE (op1));
1667
1668   /* If one of the operands must be floated, we cannot optimize.  */
1669   real1 = TREE_CODE (TREE_TYPE (primop0)) == REAL_TYPE;
1670   real2 = TREE_CODE (TREE_TYPE (primop1)) == REAL_TYPE;
1671
1672   /* If first arg is constant, swap the args (changing operation
1673      so value is preserved), for canonicalization.  Don't do this if
1674      the second arg is 0.  */
1675
1676   if (TREE_CONSTANT (primop0)
1677       && ! integer_zerop (primop1) && ! real_zerop (primop1))
1678     {
1679       register tree tem = primop0;
1680       register int temi = unsignedp0;
1681       primop0 = primop1;
1682       primop1 = tem;
1683       tem = op0;
1684       op0 = op1;
1685       op1 = tem;
1686       *op0_ptr = op0;
1687       *op1_ptr = op1;
1688       unsignedp0 = unsignedp1;
1689       unsignedp1 = temi;
1690       temi = real1;
1691       real1 = real2;
1692       real2 = temi;
1693
1694       switch (code)
1695         {
1696         case LT_EXPR:
1697           code = GT_EXPR;
1698           break;
1699         case GT_EXPR:
1700           code = LT_EXPR;
1701           break;
1702         case LE_EXPR:
1703           code = GE_EXPR;
1704           break;
1705         case GE_EXPR:
1706           code = LE_EXPR;
1707           break;
1708         }
1709       *rescode_ptr = code;
1710     }
1711
1712   /* If comparing an integer against a constant more bits wide,
1713      maybe we can deduce a value of 1 or 0 independent of the data.
1714      Or else truncate the constant now
1715      rather than extend the variable at run time.
1716
1717      This is only interesting if the constant is the wider arg.
1718      Also, it is not safe if the constant is unsigned and the
1719      variable arg is signed, since in this case the variable
1720      would be sign-extended and then regarded as unsigned.
1721      Our technique fails in this case because the lowest/highest
1722      possible unsigned results don't follow naturally from the
1723      lowest/highest possible values of the variable operand.
1724      For just EQ_EXPR and NE_EXPR there is another technique that
1725      could be used: see if the constant can be faithfully represented
1726      in the other operand's type, by truncating it and reextending it
1727      and see if that preserves the constant's value.  */
1728
1729   if (!real1 && !real2
1730       && TREE_CODE (primop1) == INTEGER_CST
1731       && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr))
1732     {
1733       int min_gt, max_gt, min_lt, max_lt;
1734       tree maxval, minval;
1735       /* 1 if comparison is nominally unsigned.  */
1736       int unsignedp = TREE_UNSIGNED (*restype_ptr);
1737       tree val;
1738
1739       type = signed_or_unsigned_type (unsignedp0, TREE_TYPE (primop0));
1740
1741       maxval = TYPE_MAX_VALUE (type);
1742       minval = TYPE_MIN_VALUE (type);
1743
1744       if (unsignedp && !unsignedp0)
1745         *restype_ptr = signed_type (*restype_ptr);
1746
1747       if (TREE_TYPE (primop1) != *restype_ptr)
1748         primop1 = convert (*restype_ptr, primop1);
1749       if (type != *restype_ptr)
1750         {
1751           minval = convert (*restype_ptr, minval);
1752           maxval = convert (*restype_ptr, maxval);
1753         }
1754
1755       if (unsignedp && unsignedp0)
1756         {
1757           min_gt = INT_CST_LT_UNSIGNED (primop1, minval);
1758           max_gt = INT_CST_LT_UNSIGNED (primop1, maxval);
1759           min_lt = INT_CST_LT_UNSIGNED (minval, primop1);
1760           max_lt = INT_CST_LT_UNSIGNED (maxval, primop1);
1761         }
1762       else
1763         {
1764           min_gt = INT_CST_LT (primop1, minval);
1765           max_gt = INT_CST_LT (primop1, maxval);
1766           min_lt = INT_CST_LT (minval, primop1);
1767           max_lt = INT_CST_LT (maxval, primop1);
1768         }
1769
1770       val = 0;
1771       /* This used to be a switch, but Genix compiler can't handle that.  */
1772       if (code == NE_EXPR)
1773         {
1774           if (max_lt || min_gt)
1775             val = boolean_true_node;
1776         }
1777       else if (code == EQ_EXPR)
1778         {
1779           if (max_lt || min_gt)
1780             val = boolean_false_node;
1781         }
1782       else if (code == LT_EXPR)
1783         {
1784           if (max_lt)
1785             val = boolean_true_node;
1786           if (!min_lt)
1787             val = boolean_false_node;
1788         }
1789       else if (code == GT_EXPR)
1790         {
1791           if (min_gt)
1792             val = boolean_true_node;
1793           if (!max_gt)
1794             val = boolean_false_node;
1795         }
1796       else if (code == LE_EXPR)
1797         {
1798           if (!max_gt)
1799             val = boolean_true_node;
1800           if (min_gt)
1801             val = boolean_false_node;
1802         }
1803       else if (code == GE_EXPR)
1804         {
1805           if (!min_lt)
1806             val = boolean_true_node;
1807           if (max_lt)
1808             val = boolean_false_node;
1809         }
1810
1811       /* If primop0 was sign-extended and unsigned comparison specd,
1812          we did a signed comparison above using the signed type bounds.
1813          But the comparison we output must be unsigned.
1814
1815          Also, for inequalities, VAL is no good; but if the signed
1816          comparison had *any* fixed result, it follows that the
1817          unsigned comparison just tests the sign in reverse
1818          (positive values are LE, negative ones GE).
1819          So we can generate an unsigned comparison
1820          against an extreme value of the signed type.  */
1821
1822       if (unsignedp && !unsignedp0)
1823         {
1824           if (val != 0)
1825             switch (code)
1826               {
1827               case LT_EXPR:
1828               case GE_EXPR:
1829                 primop1 = TYPE_MIN_VALUE (type);
1830                 val = 0;
1831                 break;
1832
1833               case LE_EXPR:
1834               case GT_EXPR:
1835                 primop1 = TYPE_MAX_VALUE (type);
1836                 val = 0;
1837                 break;
1838               }
1839           type = unsigned_type (type);
1840         }
1841
1842       if (!max_gt && !unsignedp0 && TREE_CODE (primop0) != INTEGER_CST)
1843         {
1844           /* This is the case of (char)x >?< 0x80, which people used to use
1845              expecting old C compilers to change the 0x80 into -0x80.  */
1846           if (val == boolean_false_node)
1847             warning ("comparison is always 0 due to limited range of data type");
1848           if (val == boolean_true_node)
1849             warning ("comparison is always 1 due to limited range of data type");
1850         }
1851
1852       if (!min_lt && unsignedp0 && TREE_CODE (primop0) != INTEGER_CST)
1853         {
1854           /* This is the case of (unsigned char)x >?< -1 or < 0.  */
1855           if (val == boolean_false_node)
1856             warning ("comparison is always 0 due to limited range of data type");
1857           if (val == boolean_true_node)
1858             warning ("comparison is always 1 due to limited range of data type");
1859         }
1860
1861       if (val != 0)
1862         {
1863           /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
1864           if (TREE_SIDE_EFFECTS (primop0))
1865             return build (COMPOUND_EXPR, TREE_TYPE (val), primop0, val);
1866           return val;
1867         }
1868
1869       /* Value is not predetermined, but do the comparison
1870          in the type of the operand that is not constant.
1871          TYPE is already properly set.  */
1872     }
1873   else if (real1 && real2
1874            && (TYPE_PRECISION (TREE_TYPE (primop0))
1875                == TYPE_PRECISION (TREE_TYPE (primop1))))
1876     type = TREE_TYPE (primop0);
1877
1878   /* If args' natural types are both narrower than nominal type
1879      and both extend in the same manner, compare them
1880      in the type of the wider arg.
1881      Otherwise must actually extend both to the nominal
1882      common type lest different ways of extending
1883      alter the result.
1884      (eg, (short)-1 == (unsigned short)-1  should be 0.)  */
1885
1886   else if (unsignedp0 == unsignedp1 && real1 == real2
1887            && TYPE_PRECISION (TREE_TYPE (primop0)) < TYPE_PRECISION (*restype_ptr)
1888            && TYPE_PRECISION (TREE_TYPE (primop1)) < TYPE_PRECISION (*restype_ptr))
1889     {
1890       type = common_type (TREE_TYPE (primop0), TREE_TYPE (primop1));
1891       type = signed_or_unsigned_type (unsignedp0
1892                                       || TREE_UNSIGNED (*restype_ptr),
1893                                       type);
1894       /* Make sure shorter operand is extended the right way
1895          to match the longer operand.  */
1896       primop0 = convert (signed_or_unsigned_type (unsignedp0, TREE_TYPE (primop0)),
1897                          primop0);
1898       primop1 = convert (signed_or_unsigned_type (unsignedp1, TREE_TYPE (primop1)),
1899                          primop1);
1900     }
1901   else
1902     {
1903       /* Here we must do the comparison on the nominal type
1904          using the args exactly as we received them.  */
1905       type = *restype_ptr;
1906       primop0 = op0;
1907       primop1 = op1;
1908
1909       if (!real1 && !real2 && integer_zerop (primop1)
1910           && TREE_UNSIGNED (*restype_ptr))
1911         {
1912           tree value = 0;
1913           switch (code)
1914             {
1915             case GE_EXPR:
1916               /* All unsigned values are >= 0, so we warn if extra warnings
1917                  are requested.  However, if OP0 is a constant that is
1918                  >= 0, the signedness of the comparison isn't an issue,
1919                  so suppress the warning.  */
1920               if (extra_warnings
1921                   && ! (TREE_CODE (primop0) == INTEGER_CST
1922                         && ! TREE_OVERFLOW (convert (signed_type (type),
1923                                                      primop0))))
1924                 warning ("unsigned value >= 0 is always 1");
1925               value = boolean_true_node;
1926               break;
1927
1928             case LT_EXPR:
1929               if (extra_warnings
1930                   && ! (TREE_CODE (primop0) == INTEGER_CST
1931                         && ! TREE_OVERFLOW (convert (signed_type (type),
1932                                                      primop0))))
1933                 warning ("unsigned value < 0 is always 0");
1934               value = boolean_false_node;
1935             }
1936
1937           if (value != 0)
1938             {
1939               /* Don't forget to evaluate PRIMOP0 if it has side effects.  */
1940               if (TREE_SIDE_EFFECTS (primop0))
1941                 return build (COMPOUND_EXPR, TREE_TYPE (value),
1942                               primop0, value);
1943               return value;
1944             }
1945         }
1946     }
1947
1948   *op0_ptr = convert (type, primop0);
1949   *op1_ptr = convert (type, primop1);
1950
1951   *restype_ptr = boolean_type_node;
1952
1953   return 0;
1954 }
1955 \f
1956 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR,
1957    or validate its data type for an `if' or `while' statement or ?..: exp.
1958
1959    This preparation consists of taking the ordinary
1960    representation of an expression expr and producing a valid tree
1961    boolean expression describing whether expr is nonzero.  We could
1962    simply always do build_binary_op (NE_EXPR, expr, boolean_false_node, 1),
1963    but we optimize comparisons, &&, ||, and !.
1964
1965    The resulting type should always be `boolean_type_node'.  */
1966
1967 tree
1968 truthvalue_conversion (expr)
1969      tree expr;
1970 {
1971   if (TREE_CODE (expr) == ERROR_MARK)
1972     return expr;
1973
1974 #if 0 /* This appears to be wrong for C++.  */
1975   /* These really should return error_mark_node after 2.4 is stable.
1976      But not all callers handle ERROR_MARK properly.  */
1977   switch (TREE_CODE (TREE_TYPE (expr)))
1978     {
1979     case RECORD_TYPE:
1980       error ("struct type value used where scalar is required");
1981       return boolean_false_node;
1982
1983     case UNION_TYPE:
1984       error ("union type value used where scalar is required");
1985       return boolean_false_node;
1986
1987     case ARRAY_TYPE:
1988       error ("array type value used where scalar is required");
1989       return boolean_false_node;
1990
1991     default:
1992       break;
1993     }
1994 #endif /* 0 */
1995
1996   switch (TREE_CODE (expr))
1997     {
1998       /* It is simpler and generates better code to have only TRUTH_*_EXPR
1999          or comparison expressions as truth values at this level.  */
2000 #if 0
2001     case COMPONENT_REF:
2002       /* A one-bit unsigned bit-field is already acceptable.  */
2003       if (1 == TREE_INT_CST_LOW (DECL_SIZE (TREE_OPERAND (expr, 1)))
2004           && TREE_UNSIGNED (TREE_OPERAND (expr, 1)))
2005         return expr;
2006       break;
2007 #endif
2008
2009     case EQ_EXPR:
2010       /* It is simpler and generates better code to have only TRUTH_*_EXPR
2011          or comparison expressions as truth values at this level.  */
2012 #if 0
2013       if (integer_zerop (TREE_OPERAND (expr, 1)))
2014         return build_unary_op (TRUTH_NOT_EXPR, TREE_OPERAND (expr, 0), 0);
2015 #endif
2016     case NE_EXPR: case LE_EXPR: case GE_EXPR: case LT_EXPR: case GT_EXPR:
2017     case TRUTH_ANDIF_EXPR:
2018     case TRUTH_ORIF_EXPR:
2019     case TRUTH_AND_EXPR:
2020     case TRUTH_OR_EXPR:
2021     case TRUTH_XOR_EXPR:
2022       TREE_TYPE (expr) = boolean_type_node;
2023       return expr;
2024
2025     case ERROR_MARK:
2026       return expr;
2027
2028     case INTEGER_CST:
2029       return integer_zerop (expr) ? boolean_false_node : boolean_true_node;
2030
2031     case REAL_CST:
2032       return real_zerop (expr) ? boolean_false_node : boolean_true_node;
2033
2034     case ADDR_EXPR:
2035       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0)))
2036         return build (COMPOUND_EXPR, boolean_type_node,
2037                       TREE_OPERAND (expr, 0), boolean_true_node);
2038       else
2039         return boolean_true_node;
2040
2041     case COMPLEX_EXPR:
2042       return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))
2043                                ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2044                               truthvalue_conversion (TREE_OPERAND (expr, 0)),
2045                               truthvalue_conversion (TREE_OPERAND (expr, 1)),
2046                               0);
2047
2048     case NEGATE_EXPR:
2049     case ABS_EXPR:
2050     case FLOAT_EXPR:
2051     case FFS_EXPR:
2052       /* These don't change whether an object is non-zero or zero.  */
2053       return truthvalue_conversion (TREE_OPERAND (expr, 0));
2054
2055     case LROTATE_EXPR:
2056     case RROTATE_EXPR:
2057       /* These don't change whether an object is zero or non-zero, but
2058          we can't ignore them if their second arg has side-effects.  */
2059       if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1)))
2060         return build (COMPOUND_EXPR, boolean_type_node, TREE_OPERAND (expr, 1),
2061                       truthvalue_conversion (TREE_OPERAND (expr, 0)));
2062       else
2063         return truthvalue_conversion (TREE_OPERAND (expr, 0));
2064
2065     case COND_EXPR:
2066       /* Distribute the conversion into the arms of a COND_EXPR.  */
2067       return fold (build (COND_EXPR, boolean_type_node, TREE_OPERAND (expr, 0),
2068                           truthvalue_conversion (TREE_OPERAND (expr, 1)),
2069                           truthvalue_conversion (TREE_OPERAND (expr, 2))));
2070
2071     case CONVERT_EXPR:
2072       /* Don't cancel the effect of a CONVERT_EXPR from a REFERENCE_TYPE,
2073          since that affects how `default_conversion' will behave.  */
2074       if (TREE_CODE (TREE_TYPE (expr)) == REFERENCE_TYPE
2075           || TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == REFERENCE_TYPE)
2076         break;
2077       /* fall through... */
2078     case NOP_EXPR:
2079       /* If this is widening the argument, we can ignore it.  */
2080       if (TYPE_PRECISION (TREE_TYPE (expr))
2081           >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (expr, 0))))
2082         return truthvalue_conversion (TREE_OPERAND (expr, 0));
2083       break;
2084
2085     case MINUS_EXPR:
2086       /* With IEEE arithmetic, x - x may not equal 0, so we can't optimize
2087          this case.  */
2088       if (TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
2089           && TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE)
2090         break;
2091       /* fall through... */
2092     case BIT_XOR_EXPR:
2093       /* This and MINUS_EXPR can be changed into a comparison of the
2094          two objects.  */
2095       if (TREE_TYPE (TREE_OPERAND (expr, 0))
2096           == TREE_TYPE (TREE_OPERAND (expr, 1)))
2097         return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2098                                 TREE_OPERAND (expr, 1), 1);
2099       return build_binary_op (NE_EXPR, TREE_OPERAND (expr, 0),
2100                               fold (build1 (NOP_EXPR,
2101                                             TREE_TYPE (TREE_OPERAND (expr, 0)),
2102                                             TREE_OPERAND (expr, 1))), 1);
2103
2104     case BIT_AND_EXPR:
2105       if (integer_onep (TREE_OPERAND (expr, 1)))
2106         return expr;
2107
2108     case MODIFY_EXPR:
2109       if (warn_parentheses && C_EXP_ORIGINAL_CODE (expr) == MODIFY_EXPR)
2110         warning ("suggest parentheses around assignment used as truth value");
2111       break;
2112     }
2113
2114   if (TREE_CODE (TREE_TYPE (expr)) == COMPLEX_TYPE)
2115     return (build_binary_op
2116             ((TREE_SIDE_EFFECTS (expr)
2117               ? TRUTH_OR_EXPR : TRUTH_ORIF_EXPR),
2118              truthvalue_conversion (build_unary_op (REALPART_EXPR, expr, 0)),
2119              truthvalue_conversion (build_unary_op (IMAGPART_EXPR, expr, 0)),
2120              0));
2121
2122   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);
2123 }
2124 \f
2125 /* Read the rest of a #-directive from input stream FINPUT.
2126    In normal use, the directive name and the white space after it
2127    have already been read, so they won't be included in the result.
2128    We allow for the fact that the directive line may contain
2129    a newline embedded within a character or string literal which forms
2130    a part of the directive.
2131
2132    The value is a string in a reusable buffer.  It remains valid
2133    only until the next time this function is called.  */
2134
2135 char *
2136 get_directive_line (finput)
2137      register FILE *finput;
2138 {
2139   static char *directive_buffer = NULL;
2140   static unsigned buffer_length = 0;
2141   register char *p;
2142   register char *buffer_limit;
2143   register int looking_for = 0;
2144   register int char_escaped = 0;
2145
2146   if (buffer_length == 0)
2147     {
2148       directive_buffer = (char *)xmalloc (128);
2149       buffer_length = 128;
2150     }
2151
2152   buffer_limit = &directive_buffer[buffer_length];
2153
2154   for (p = directive_buffer; ; )
2155     {
2156       int c;
2157
2158       /* Make buffer bigger if it is full.  */
2159       if (p >= buffer_limit)
2160         {
2161           register unsigned bytes_used = (p - directive_buffer);
2162
2163           buffer_length *= 2;
2164           directive_buffer
2165             = (char *)xrealloc (directive_buffer, buffer_length);
2166           p = &directive_buffer[bytes_used];
2167           buffer_limit = &directive_buffer[buffer_length];
2168         }
2169
2170       c = getc (finput);
2171
2172       /* Discard initial whitespace.  */
2173       if ((c == ' ' || c == '\t') && p == directive_buffer)
2174         continue;
2175
2176       /* Detect the end of the directive.  */
2177       if (c == '\n' && looking_for == 0)
2178         {
2179           ungetc (c, finput);
2180           c = '\0';
2181         }
2182
2183       *p++ = c;
2184
2185       if (c == 0)
2186         return directive_buffer;
2187
2188       /* Handle string and character constant syntax.  */
2189       if (looking_for)
2190         {
2191           if (looking_for == c && !char_escaped)
2192             looking_for = 0;    /* Found terminator... stop looking.  */
2193         }
2194       else
2195         if (c == '\'' || c == '"')
2196           looking_for = c;      /* Don't stop buffering until we see another
2197                                    another one of these (or an EOF).  */
2198
2199       /* Handle backslash.  */
2200       char_escaped = (c == '\\' && ! char_escaped);
2201     }
2202 }
2203 \f
2204 /* Make a variant type in the proper way for C/C++, propagating qualifiers
2205    down to the element type of an array.  */
2206
2207 tree
2208 c_build_type_variant (type, constp, volatilep)
2209      tree type;
2210      int constp, volatilep;
2211 {
2212   if (TREE_CODE (type) == ARRAY_TYPE)
2213     {
2214       tree real_main_variant = TYPE_MAIN_VARIANT (type);
2215
2216       push_obstacks (TYPE_OBSTACK (real_main_variant),
2217                      TYPE_OBSTACK (real_main_variant));
2218       type = build_array_type (c_build_type_variant (TREE_TYPE (type),
2219                                                      constp, volatilep),
2220                                TYPE_DOMAIN (type));
2221
2222       /* TYPE must be on same obstack as REAL_MAIN_VARIANT.  If not,
2223          make a copy.  (TYPE might have come from the hash table and
2224          REAL_MAIN_VARIANT might be in some function's obstack.)  */
2225
2226       if (TYPE_OBSTACK (type) != TYPE_OBSTACK (real_main_variant))
2227         {
2228           type = copy_node (type);
2229           TYPE_POINTER_TO (type) = TYPE_REFERENCE_TO (type) = 0;
2230         }
2231
2232       TYPE_MAIN_VARIANT (type) = real_main_variant;
2233       pop_obstacks ();
2234     }
2235   return build_type_variant (type, constp, volatilep);
2236 }