gdb/compile/compile-c-types.c

   1 /* Convert types from GDB to GCC
   2
   3    Copyright (C) 2014 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
  21 #include "defs.h"
  22 #include "gdbtypes.h"
  23 #include "compile-internal.h"
  24 #include "gdb_assert.h"
  25
  26 /* An object that maps a gdb type to a gcc type.  */
  27
  28 struct type_map_instance
  29 {
  30   /* The gdb type.  */
  31
  32   struct type *type;
  33
  34   /* The corresponding gcc type handle.  */
  35
  36   gcc_type gcc_type;
  37 };
  38
  39 /* Hash a type_map_instance.  */
  40
  41 static hashval_t
  42 hash_type_map_instance (const void *p)
  43 {
  44   const struct type_map_instance *inst = p;
  45
  46   return htab_hash_pointer (inst->type);
  47 }
  48
  49 /* Check two type_map_instance objects for equality.  */
  50
  51 static int
  52 eq_type_map_instance (const void *a, const void *b)
  53 {
  54   const struct type_map_instance *insta = a;
  55   const struct type_map_instance *instb = b;
  56
  57   return insta->type == instb->type;
  58 }
  59
  60 \f
  61
  62 /* Insert an entry into the type map associated with CONTEXT that maps
  63    from the gdb type TYPE to the gcc type GCC_TYPE.  It is ok for a
  64    given type to be inserted more than once, provided that the exact
  65    same association is made each time.  This simplifies how type
  66    caching works elsewhere in this file -- see how struct type caching
  67    is handled.  */
  68
  69 static void
  70 insert_type (struct compile_c_instance *context, struct type *type,
  71              gcc_type gcc_type)
  72 {
  73   struct type_map_instance inst, *add;
  74   void **slot;
  75
  76   inst.type = type;
  77   inst.gcc_type = gcc_type;
  78   slot = htab_find_slot (context->type_map, &inst, INSERT);
  79
  80   add = *slot;
  81   /* The type might have already been inserted in order to handle
  82      recursive types.  */
  83   gdb_assert (add == NULL || add->gcc_type == gcc_type);
  84
  85   if (add == NULL)
  86     {
  87       add = XNEW (struct type_map_instance);
  88       *add = inst;
  89       *slot = add;
  90     }
  91 }
  92
  93 /* Convert a pointer type to its gcc representation.  */
  94
  95 static gcc_type
  96 convert_pointer (struct compile_c_instance *context, struct type *type)
  97 {
  98   gcc_type target = convert_type (context, TYPE_TARGET_TYPE (type));
  99
 100   return C_CTX (context)->c_ops->build_pointer_type (C_CTX (context),
 101                                                      target);
 102 }
 103
 104 /* Convert an array type to its gcc representation.  */
 105
 106 static gcc_type
 107 convert_array (struct compile_c_instance *context, struct type *type)
 108 {
 109   gcc_type element_type;
 110   struct type *range = TYPE_INDEX_TYPE (type);
 111
 112   element_type = convert_type (context, TYPE_TARGET_TYPE (type));
 113
 114   if (TYPE_LOW_BOUND_KIND (range) != PROP_CONST)
 115     return C_CTX (context)->c_ops->error (C_CTX (context),
 116                                           _("array type with non-constant"
 117                                             " lower bound is not supported"));
 118   if (TYPE_LOW_BOUND (range) != 0)
 119     return C_CTX (context)->c_ops->error (C_CTX (context),
 120                                           _("cannot convert array type with "
 121                                             "non-zero lower bound to C"));
 122
 123   if (TYPE_HIGH_BOUND_KIND (range) == PROP_LOCEXPR
 124       || TYPE_HIGH_BOUND_KIND (range) == PROP_LOCLIST)
 125     {
 126       gcc_type result;
 127       char *upper_bound;
 128
 129       if (TYPE_VECTOR (type))
 130         return C_CTX (context)->c_ops->error (C_CTX (context),
 131                                               _("variably-sized vector type"
 132                                                 " is not supported"));
 133
 134       upper_bound = c_get_range_decl_name (&TYPE_RANGE_DATA (range)->high);
 135       result = C_CTX (context)->c_ops->build_vla_array_type (C_CTX (context),
 136                                                              element_type,
 137                                                              upper_bound);
 138       xfree (upper_bound);
 139       return result;
 140     }
 141   else
 142     {
 143       LONGEST low_bound, high_bound, count;
 144
 145       if (get_array_bounds (type, &low_bound, &high_bound) == 0)
 146         count = -1;
 147       else
 148         {
 149           gdb_assert (low_bound == 0); /* Ensured above.  */
 150           count = high_bound + 1;
 151         }
 152
 153       if (TYPE_VECTOR (type))
 154         return C_CTX (context)->c_ops->build_vector_type (C_CTX (context),
 155                                                           element_type,
 156                                                           count);
 157       return C_CTX (context)->c_ops->build_array_type (C_CTX (context),
 158                                                        element_type, count);
 159     }
 160 }
 161
 162 /* Convert a struct or union type to its gcc representation.  */
 163
 164 static gcc_type
 165 convert_struct_or_union (struct compile_c_instance *context, struct type *type)
 166 {
 167   int i;
 168   gcc_type result;
 169
 170   /* First we create the resulting type and enter it into our hash
 171      table.  This lets recursive types work.  */
 172   if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
 173     result = C_CTX (context)->c_ops->build_record_type (C_CTX (context));
 174   else
 175     {
 176       gdb_assert (TYPE_CODE (type) == TYPE_CODE_UNION);
 177       result = C_CTX (context)->c_ops->build_union_type (C_CTX (context));
 178     }
 179   insert_type (context, type, result);
 180
 181   for (i = 0; i < TYPE_NFIELDS (type); ++i)
 182     {
 183       gcc_type field_type;
 184       unsigned long bitsize = TYPE_FIELD_BITSIZE (type, i);
 185
 186       field_type = convert_type (context, TYPE_FIELD_TYPE (type, i));
 187       if (bitsize == 0)
 188         bitsize = 8 * TYPE_LENGTH (TYPE_FIELD_TYPE (type, i));
 189       C_CTX (context)->c_ops->build_add_field (C_CTX (context), result,
 190                                                TYPE_FIELD_NAME (type, i),
 191                                                field_type,
 192                                                bitsize,
 193                                                TYPE_FIELD_BITPOS (type, i));
 194     }
 195
 196   C_CTX (context)->c_ops->finish_record_or_union (C_CTX (context), result,
 197                                                   TYPE_LENGTH (type));
 198   return result;
 199 }
 200
 201 /* Convert an enum type to its gcc representation.  */
 202
 203 static gcc_type
 204 convert_enum (struct compile_c_instance *context, struct type *type)
 205 {
 206   gcc_type int_type, result;
 207   int i;
 208   struct gcc_c_context *ctx = C_CTX (context);
 209
 210   int_type = ctx->c_ops->int_type (ctx,
 211                                    TYPE_UNSIGNED (type),
 212                                    TYPE_LENGTH (type));
 213
 214   result = ctx->c_ops->build_enum_type (ctx, int_type);
 215   for (i = 0; i < TYPE_NFIELDS (type); ++i)
 216     {
 217       ctx->c_ops->build_add_enum_constant (ctx,
 218                                            result,
 219                                            TYPE_FIELD_NAME (type, i),
 220                                            TYPE_FIELD_ENUMVAL (type, i));
 221     }
 222
 223   ctx->c_ops->finish_enum_type (ctx, result);
 224
 225   return result;
 226 }
 227
 228 /* Convert a function type to its gcc representation.  */
 229
 230 static gcc_type
 231 convert_func (struct compile_c_instance *context, struct type *type)
 232 {
 233   int i;
 234   gcc_type result, return_type;
 235   struct gcc_type_array array;
 236   int is_varargs = TYPE_VARARGS (type) || !TYPE_PROTOTYPED (type);
 237
 238   /* This approach means we can't make self-referential function
 239      types.  Those are impossible in C, though.  */
 240   return_type = convert_type (context, TYPE_TARGET_TYPE (type));
 241
 242   array.n_elements = TYPE_NFIELDS (type);
 243   array.elements = XNEWVEC (gcc_type, TYPE_NFIELDS (type));
 244   for (i = 0; i < TYPE_NFIELDS (type); ++i)
 245     array.elements[i] = convert_type (context, TYPE_FIELD_TYPE (type, i));
 246
 247   result = C_CTX (context)->c_ops->build_function_type (C_CTX (context),
 248                                                         return_type,
 249                                                         &array, is_varargs);
 250   xfree (array.elements);
 251
 252   return result;
 253 }
 254
 255 /* Convert an integer type to its gcc representation.  */
 256
 257 static gcc_type
 258 convert_int (struct compile_c_instance *context, struct type *type)
 259 {
 260   return C_CTX (context)->c_ops->int_type (C_CTX (context),
 261                                            TYPE_UNSIGNED (type),
 262                                            TYPE_LENGTH (type));
 263 }
 264
 265 /* Convert a floating-point type to its gcc representation.  */
 266
 267 static gcc_type
 268 convert_float (struct compile_c_instance *context, struct type *type)
 269 {
 270   return C_CTX (context)->c_ops->float_type (C_CTX (context),
 271                                              TYPE_LENGTH (type));
 272 }
 273
 274 /* Convert the 'void' type to its gcc representation.  */
 275
 276 static gcc_type
 277 convert_void (struct compile_c_instance *context, struct type *type)
 278 {
 279   return C_CTX (context)->c_ops->void_type (C_CTX (context));
 280 }
 281
 282 /* Convert a boolean type to its gcc representation.  */
 283
 284 static gcc_type
 285 convert_bool (struct compile_c_instance *context, struct type *type)
 286 {
 287   return C_CTX (context)->c_ops->bool_type (C_CTX (context));
 288 }
 289
 290 /* Convert a qualified type to its gcc representation.  */
 291
 292 static gcc_type
 293 convert_qualified (struct compile_c_instance *context, struct type *type)
 294 {
 295   struct type *unqual = make_unqualified_type (type);
 296   gcc_type unqual_converted;
 297   int quals = 0;
 298
 299   unqual_converted = convert_type (context, unqual);
 300
 301   if (TYPE_CONST (type))
 302     quals |= GCC_QUALIFIER_CONST;
 303   if (TYPE_VOLATILE (type))
 304     quals |= GCC_QUALIFIER_VOLATILE;
 305   if (TYPE_RESTRICT (type))
 306     quals |= GCC_QUALIFIER_RESTRICT;
 307
 308   return C_CTX (context)->c_ops->build_qualified_type (C_CTX (context),
 309                                                        unqual_converted,
 310                                                        quals);
 311 }
 312
 313 /* Convert a complex type to its gcc representation.  */
 314
 315 static gcc_type
 316 convert_complex (struct compile_c_instance *context, struct type *type)
 317 {
 318   gcc_type base = convert_type (context, TYPE_TARGET_TYPE (type));
 319
 320   return C_CTX (context)->c_ops->build_complex_type (C_CTX (context), base);
 321 }
 322
 323 /* A helper function which knows how to convert most types from their
 324    gdb representation to the corresponding gcc form.  This examines
 325    the TYPE and dispatches to the appropriate conversion function.  It
 326    returns the gcc type.  */
 327
 328 static gcc_type
 329 convert_type_basic (struct compile_c_instance *context, struct type *type)
 330 {
 331   /* If we are converting a qualified type, first convert the
 332      unqualified type and then apply the qualifiers.  */
 333   if ((TYPE_INSTANCE_FLAGS (type) & (TYPE_INSTANCE_FLAG_CONST
 334                                      | TYPE_INSTANCE_FLAG_VOLATILE
 335                                      | TYPE_INSTANCE_FLAG_RESTRICT)) != 0)
 336     return convert_qualified (context, type);
 337
 338   switch (TYPE_CODE (type))
 339     {
 340     case TYPE_CODE_PTR:
 341       return convert_pointer (context, type);
 342
 343     case TYPE_CODE_ARRAY:
 344       return convert_array (context, type);
 345
 346     case TYPE_CODE_STRUCT:
 347     case TYPE_CODE_UNION:
 348       return convert_struct_or_union (context, type);
 349
 350     case TYPE_CODE_ENUM:
 351       return convert_enum (context, type);
 352
 353     case TYPE_CODE_FUNC:
 354       return convert_func (context, type);
 355
 356     case TYPE_CODE_INT:
 357       return convert_int (context, type);
 358
 359     case TYPE_CODE_FLT:
 360       return convert_float (context, type);
 361
 362     case TYPE_CODE_VOID:
 363       return convert_void (context, type);
 364
 365     case TYPE_CODE_BOOL:
 366       return convert_bool (context, type);
 367
 368     case TYPE_CODE_COMPLEX:
 369       return convert_complex (context, type);
 370     }
 371
 372   return C_CTX (context)->c_ops->error (C_CTX (context),
 373                                         _("cannot convert gdb type "
 374                                           "to gcc type"));
 375 }
 376
 377 /* See compile-internal.h.  */
 378
 379 gcc_type
 380 convert_type (struct compile_c_instance *context, struct type *type)
 381 {
 382   struct type_map_instance inst, *found;
 383   gcc_type result;
 384
 385   /* We don't ever have to deal with typedefs in this code, because
 386      those are only needed as symbols by the C compiler.  */
 387   CHECK_TYPEDEF (type);
 388
 389   inst.type = type;
 390   found = htab_find (context->type_map, &inst);
 391   if (found != NULL)
 392     return found->gcc_type;
 393
 394   result = convert_type_basic (context, type);
 395   insert_type (context, type, result);
 396   return result;
 397 }
 398
 399 \f
 400
 401 /* Delete the compiler instance C.  */
 402
 403 static void
 404 delete_instance (struct compile_instance *c)
 405 {
 406   struct compile_c_instance *context = (struct compile_c_instance *) c;
 407
 408   context->base.fe->ops->destroy (context->base.fe);
 409   htab_delete (context->type_map);
 410   if (context->symbol_err_map != NULL)
 411     htab_delete (context->symbol_err_map);
 412   xfree (context);
 413 }
 414
 415 /* See compile-internal.h.  */
 416
 417 struct compile_instance *
 418 new_compile_instance (struct gcc_c_context *fe)
 419 {
 420   struct compile_c_instance *result = XCNEW (struct compile_c_instance);
 421
 422   result->base.fe = &fe->base;
 423   result->base.destroy = delete_instance;
 424   result->base.gcc_target_options = ("-std=gnu11"
 425                                      /* Otherwise the .o file may need
 426                                         "_Unwind_Resume" and
 427                                         "__gcc_personality_v0".  */
 428                                      " -fno-exceptions");
 429
 430   result->type_map = htab_create_alloc (10, hash_type_map_instance,
 431                                         eq_type_map_instance,
 432                                         xfree, xcalloc, xfree);
 433
 434   fe->c_ops->set_callbacks (fe, gcc_convert_symbol,
 435                             gcc_symbol_address, result);
 436
 437   return &result->base;
 438 }