gdb/m2-lang.c

   1 /* Modula 2 language support routines for GDB, the GNU debugger.
   2
   3    Copyright (C) 1992-2020 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "symtab.h"
  22 #include "gdbtypes.h"
  23 #include "expression.h"
  24 #include "parser-defs.h"
  25 #include "language.h"
  26 #include "varobj.h"
  27 #include "m2-lang.h"
  28 #include "c-lang.h"
  29 #include "valprint.h"
  30 #include "gdbarch.h"
  31
  32 static void m2_printchar (int, struct type *, struct ui_file *);
  33
  34 /* FIXME:  This is a copy of the same function from c-exp.y.  It should
  35    be replaced with a true Modula version.  */
  36
  37 static void
  38 m2_printchar (int c, struct type *type, struct ui_file *stream)
  39 {
  40   fputs_filtered ("'", stream);
  41   LA_EMIT_CHAR (c, type, stream, '\'');
  42   fputs_filtered ("'", stream);
  43 }
  44
  45 static struct value *
  46 evaluate_subexp_modula2 (struct type *expect_type, struct expression *exp,
  47                          int *pos, enum noside noside)
  48 {
  49   enum exp_opcode op = exp->elts[*pos].opcode;
  50   struct value *arg1;
  51   struct value *arg2;
  52   struct type *type;
  53
  54   switch (op)
  55     {
  56     case UNOP_HIGH:
  57       (*pos)++;
  58       arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
  59
  60       if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
  61         return arg1;
  62       else
  63         {
  64           arg1 = coerce_ref (arg1);
  65           type = check_typedef (value_type (arg1));
  66
  67           if (m2_is_unbounded_array (type))
  68             {
  69               struct value *temp = arg1;
  70
  71               type = type->field (1).type ();
  72               /* i18n: Do not translate the "_m2_high" part!  */
  73               arg1 = value_struct_elt (&temp, NULL, "_m2_high", NULL,
  74                                        _("unbounded structure "
  75                                          "missing _m2_high field"));
  76
  77               if (value_type (arg1) != type)
  78                 arg1 = value_cast (type, arg1);
  79             }
  80         }
  81       return arg1;
  82
  83     case BINOP_SUBSCRIPT:
  84       (*pos)++;
  85       arg1 = evaluate_subexp_with_coercion (exp, pos, noside);
  86       arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
  87       if (noside == EVAL_SKIP)
  88         goto nosideret;
  89       /* If the user attempts to subscript something that is not an
  90          array or pointer type (like a plain int variable for example),
  91          then report this as an error.  */
  92
  93       arg1 = coerce_ref (arg1);
  94       type = check_typedef (value_type (arg1));
  95
  96       if (m2_is_unbounded_array (type))
  97         {
  98           struct value *temp = arg1;
  99           type = type->field (0).type ();
 100           if (type == NULL || (type->code () != TYPE_CODE_PTR))
 101             {
 102               warning (_("internal error: unbounded "
 103                          "array structure is unknown"));
 104               return evaluate_subexp_standard (expect_type, exp, pos, noside);
 105             }
 106           /* i18n: Do not translate the "_m2_contents" part!  */
 107           arg1 = value_struct_elt (&temp, NULL, "_m2_contents", NULL,
 108                                    _("unbounded structure "
 109                                      "missing _m2_contents field"));
 110
 111           if (value_type (arg1) != type)
 112             arg1 = value_cast (type, arg1);
 113
 114           check_typedef (value_type (arg1));
 115           return value_ind (value_ptradd (arg1, value_as_long (arg2)));
 116         }
 117       else
 118         if (type->code () != TYPE_CODE_ARRAY)
 119           {
 120             if (type->name ())
 121               error (_("cannot subscript something of type `%s'"),
 122                      type->name ());
 123             else
 124               error (_("cannot subscript requested type"));
 125           }
 126
 127       if (noside == EVAL_AVOID_SIDE_EFFECTS)
 128         return value_zero (TYPE_TARGET_TYPE (type), VALUE_LVAL (arg1));
 129       else
 130         return value_subscript (arg1, value_as_long (arg2));
 131
 132     default:
 133       return evaluate_subexp_standard (expect_type, exp, pos, noside);
 134     }
 135
 136  nosideret:
 137   return value_from_longest (builtin_type (exp->gdbarch)->builtin_int, 1);
 138 }
 139 \f
 140
 141 /* Table of operators and their precedences for printing expressions.  */
 142
 143 static const struct op_print m2_op_print_tab[] =
 144 {
 145   {"+", BINOP_ADD, PREC_ADD, 0},
 146   {"+", UNOP_PLUS, PREC_PREFIX, 0},
 147   {"-", BINOP_SUB, PREC_ADD, 0},
 148   {"-", UNOP_NEG, PREC_PREFIX, 0},
 149   {"*", BINOP_MUL, PREC_MUL, 0},
 150   {"/", BINOP_DIV, PREC_MUL, 0},
 151   {"DIV", BINOP_INTDIV, PREC_MUL, 0},
 152   {"MOD", BINOP_REM, PREC_MUL, 0},
 153   {":=", BINOP_ASSIGN, PREC_ASSIGN, 1},
 154   {"OR", BINOP_LOGICAL_OR, PREC_LOGICAL_OR, 0},
 155   {"AND", BINOP_LOGICAL_AND, PREC_LOGICAL_AND, 0},
 156   {"NOT", UNOP_LOGICAL_NOT, PREC_PREFIX, 0},
 157   {"=", BINOP_EQUAL, PREC_EQUAL, 0},
 158   {"<>", BINOP_NOTEQUAL, PREC_EQUAL, 0},
 159   {"<=", BINOP_LEQ, PREC_ORDER, 0},
 160   {">=", BINOP_GEQ, PREC_ORDER, 0},
 161   {">", BINOP_GTR, PREC_ORDER, 0},
 162   {"<", BINOP_LESS, PREC_ORDER, 0},
 163   {"^", UNOP_IND, PREC_PREFIX, 0},
 164   {"@", BINOP_REPEAT, PREC_REPEAT, 0},
 165   {"CAP", UNOP_CAP, PREC_BUILTIN_FUNCTION, 0},
 166   {"CHR", UNOP_CHR, PREC_BUILTIN_FUNCTION, 0},
 167   {"ORD", UNOP_ORD, PREC_BUILTIN_FUNCTION, 0},
 168   {"FLOAT", UNOP_FLOAT, PREC_BUILTIN_FUNCTION, 0},
 169   {"HIGH", UNOP_HIGH, PREC_BUILTIN_FUNCTION, 0},
 170   {"MAX", UNOP_MAX, PREC_BUILTIN_FUNCTION, 0},
 171   {"MIN", UNOP_MIN, PREC_BUILTIN_FUNCTION, 0},
 172   {"ODD", UNOP_ODD, PREC_BUILTIN_FUNCTION, 0},
 173   {"TRUNC", UNOP_TRUNC, PREC_BUILTIN_FUNCTION, 0},
 174   {NULL, OP_NULL, PREC_BUILTIN_FUNCTION, 0}
 175 };
 176 \f
 177 /* The built-in types of Modula-2.  */
 178
 179 enum m2_primitive_types {
 180   m2_primitive_type_char,
 181   m2_primitive_type_int,
 182   m2_primitive_type_card,
 183   m2_primitive_type_real,
 184   m2_primitive_type_bool,
 185   nr_m2_primitive_types
 186 };
 187
 188 const struct exp_descriptor exp_descriptor_modula2 =
 189 {
 190   print_subexp_standard,
 191   operator_length_standard,
 192   operator_check_standard,
 193   op_name_standard,
 194   dump_subexp_body_standard,
 195   evaluate_subexp_modula2
 196 };
 197
 198 /* Constant data describing the M2 language.  */
 199
 200 extern const struct language_data m2_language_data =
 201 {
 202   m2_op_print_tab,              /* expression operators for printing */
 203 };
 204
 205 /* Class representing the M2 language.  */
 206
 207 class m2_language : public language_defn
 208 {
 209 public:
 210   m2_language ()
 211     : language_defn (language_m2, m2_language_data)
 212   { /* Nothing.  */ }
 213
 214   /* See language.h.  */
 215
 216   const char *name () const override
 217   { return "modula-2"; }
 218
 219   /* See language.h.  */
 220
 221   const char *natural_name () const override
 222   { return "Modula-2"; }
 223
 224   /* See language.h.  */
 225   void language_arch_info (struct gdbarch *gdbarch,
 226                            struct language_arch_info *lai) const override
 227   {
 228     const struct builtin_m2_type *builtin = builtin_m2_type (gdbarch);
 229
 230     lai->string_char_type = builtin->builtin_char;
 231     lai->primitive_type_vector
 232       = GDBARCH_OBSTACK_CALLOC (gdbarch, nr_m2_primitive_types + 1,
 233                                 struct type *);
 234
 235     lai->primitive_type_vector [m2_primitive_type_char]
 236       = builtin->builtin_char;
 237     lai->primitive_type_vector [m2_primitive_type_int]
 238       = builtin->builtin_int;
 239     lai->primitive_type_vector [m2_primitive_type_card]
 240       = builtin->builtin_card;
 241     lai->primitive_type_vector [m2_primitive_type_real]
 242       = builtin->builtin_real;
 243     lai->primitive_type_vector [m2_primitive_type_bool]
 244       = builtin->builtin_bool;
 245
 246     lai->bool_type_symbol = "BOOLEAN";
 247     lai->bool_type_default = builtin->builtin_bool;
 248   }
 249
 250   /* See language.h.  */
 251
 252   void print_type (struct type *type, const char *varstring,
 253                    struct ui_file *stream, int show, int level,
 254                    const struct type_print_options *flags) const override
 255   {
 256     m2_print_type (type, varstring, stream, show, level, flags);
 257   }
 258
 259   /* See language.h.  */
 260
 261   void value_print_inner
 262         (struct value *val, struct ui_file *stream, int recurse,
 263          const struct value_print_options *options) const override
 264   {
 265     return m2_value_print_inner (val, stream, recurse, options);
 266   }
 267
 268   /* See language.h.  */
 269
 270   int parser (struct parser_state *ps) const override
 271   {
 272     return m2_parse (ps);
 273   }
 274
 275   /* See language.h.  */
 276
 277   void emitchar (int ch, struct type *chtype,
 278                  struct ui_file *stream, int quoter) const override
 279   {
 280     ch &= 0xFF;                 /* Avoid sign bit follies.  */
 281
 282     if (PRINT_LITERAL_FORM (ch))
 283       {
 284         if (ch == '\\' || ch == quoter)
 285           fputs_filtered ("\\", stream);
 286         fprintf_filtered (stream, "%c", ch);
 287       }
 288     else
 289       {
 290         switch (ch)
 291           {
 292           case '\n':
 293             fputs_filtered ("\\n", stream);
 294             break;
 295           case '\b':
 296             fputs_filtered ("\\b", stream);
 297             break;
 298           case '\t':
 299             fputs_filtered ("\\t", stream);
 300             break;
 301           case '\f':
 302             fputs_filtered ("\\f", stream);
 303             break;
 304           case '\r':
 305             fputs_filtered ("\\r", stream);
 306             break;
 307           case '\033':
 308             fputs_filtered ("\\e", stream);
 309             break;
 310           case '\007':
 311             fputs_filtered ("\\a", stream);
 312             break;
 313           default:
 314             fprintf_filtered (stream, "\\%.3o", (unsigned int) ch);
 315             break;
 316           }
 317       }
 318   }
 319
 320   /* See language.h.  */
 321
 322   void printchar (int ch, struct type *chtype,
 323                   struct ui_file *stream) const override
 324   {
 325     m2_printchar (ch, chtype, stream);
 326   }
 327
 328   /* See language.h.  */
 329
 330   void printstr (struct ui_file *stream, struct type *elttype,
 331                  const gdb_byte *string, unsigned int length,
 332                  const char *encoding, int force_ellipses,
 333                  const struct value_print_options *options) const override
 334   {
 335     unsigned int i;
 336     unsigned int things_printed = 0;
 337     int in_quotes = 0;
 338     int need_comma = 0;
 339
 340     if (length == 0)
 341       {
 342         fputs_filtered ("\"\"", gdb_stdout);
 343         return;
 344       }
 345
 346     for (i = 0; i < length && things_printed < options->print_max; ++i)
 347       {
 348         /* Position of the character we are examining
 349            to see whether it is repeated.  */
 350         unsigned int rep1;
 351         /* Number of repetitions we have detected so far.  */
 352         unsigned int reps;
 353
 354         QUIT;
 355
 356         if (need_comma)
 357           {
 358             fputs_filtered (", ", stream);
 359             need_comma = 0;
 360           }
 361
 362         rep1 = i + 1;
 363         reps = 1;
 364         while (rep1 < length && string[rep1] == string[i])
 365           {
 366             ++rep1;
 367             ++reps;
 368           }
 369
 370         if (reps > options->repeat_count_threshold)
 371           {
 372             if (in_quotes)
 373               {
 374                 fputs_filtered ("\", ", stream);
 375                 in_quotes = 0;
 376               }
 377             m2_printchar (string[i], elttype, stream);
 378             fprintf_filtered (stream, " <repeats %u times>", reps);
 379             i = rep1 - 1;
 380             things_printed += options->repeat_count_threshold;
 381             need_comma = 1;
 382           }
 383         else
 384           {
 385             if (!in_quotes)
 386               {
 387                 fputs_filtered ("\"", stream);
 388                 in_quotes = 1;
 389               }
 390             LA_EMIT_CHAR (string[i], elttype, stream, '"');
 391             ++things_printed;
 392           }
 393       }
 394
 395     /* Terminate the quotes if necessary.  */
 396     if (in_quotes)
 397       fputs_filtered ("\"", stream);
 398
 399     if (force_ellipses || i < length)
 400       fputs_filtered ("...", stream);
 401   }
 402
 403   /* See language.h.  */
 404
 405   void print_typedef (struct type *type, struct symbol *new_symbol,
 406                       struct ui_file *stream) const override
 407   {
 408     m2_print_typedef (type, new_symbol, stream);
 409   }
 410
 411   /* See language.h.  */
 412
 413   bool is_string_type_p (struct type *type) const override
 414   {
 415     type = check_typedef (type);
 416     if (type->code () == TYPE_CODE_ARRAY
 417         && TYPE_LENGTH (type) > 0
 418         && TYPE_LENGTH (TYPE_TARGET_TYPE (type)) > 0)
 419       {
 420         struct type *elttype = check_typedef (TYPE_TARGET_TYPE (type));
 421
 422         if (TYPE_LENGTH (elttype) == 1
 423             && (elttype->code () == TYPE_CODE_INT
 424                 || elttype->code () == TYPE_CODE_CHAR))
 425           return true;
 426       }
 427
 428     return false;
 429   }
 430
 431   /* See language.h.  */
 432
 433   bool c_style_arrays_p () const override
 434   { return false; }
 435
 436   /* See language.h.  Despite not having C-style arrays, Modula-2 uses 0
 437      for its string lower bounds.  */
 438
 439   char string_lower_bound () const override
 440   { return 0; }
 441
 442   /* See language.h.  */
 443
 444   bool range_checking_on_by_default () const override
 445   { return true; }
 446
 447   /* See language.h.  */
 448
 449   const struct exp_descriptor *expression_ops () const override
 450   { return &exp_descriptor_modula2; }
 451 };
 452
 453 /* Single instance of the M2 language.  */
 454
 455 static m2_language m2_language_defn;
 456
 457 static void *
 458 build_m2_types (struct gdbarch *gdbarch)
 459 {
 460   struct builtin_m2_type *builtin_m2_type
 461     = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct builtin_m2_type);
 462
 463   /* Modula-2 "pervasive" types.  NOTE:  these can be redefined!!! */
 464   builtin_m2_type->builtin_int
 465     = arch_integer_type (gdbarch, gdbarch_int_bit (gdbarch), 0, "INTEGER");
 466   builtin_m2_type->builtin_card
 467     = arch_integer_type (gdbarch, gdbarch_int_bit (gdbarch), 1, "CARDINAL");
 468   builtin_m2_type->builtin_real
 469     = arch_float_type (gdbarch, gdbarch_float_bit (gdbarch), "REAL",
 470                        gdbarch_float_format (gdbarch));
 471   builtin_m2_type->builtin_char
 472     = arch_character_type (gdbarch, TARGET_CHAR_BIT, 1, "CHAR");
 473   builtin_m2_type->builtin_bool
 474     = arch_boolean_type (gdbarch, gdbarch_int_bit (gdbarch), 1, "BOOLEAN");
 475
 476   return builtin_m2_type;
 477 }
 478
 479 static struct gdbarch_data *m2_type_data;
 480
 481 const struct builtin_m2_type *
 482 builtin_m2_type (struct gdbarch *gdbarch)
 483 {
 484   return (const struct builtin_m2_type *) gdbarch_data (gdbarch, m2_type_data);
 485 }
 486
 487
 488 /* Initialization for Modula-2 */
 489
 490 void _initialize_m2_language ();
 491 void
 492 _initialize_m2_language ()
 493 {
 494   m2_type_data = gdbarch_data_register_post_init (build_m2_types);
 495 }