gdb/compile/compile-c-types.c

   1 /* Convert types from GDB to GCC
   2
   3    Copyright (C) 2014-2015 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 /* An object that maps a gdb type to a gcc type.  */
  25
  26 struct type_map_instance
  27 {
  28   /* The gdb type.  */
  29
  30   struct type *type;
  31
  32   /* The corresponding gcc type handle.  */
  33
  34   gcc_type gcc_type;
  35 };
  36
  37 /* Hash a type_map_instance.  */
  38
  39 static hashval_t
  40 hash_type_map_instance (const void *p)
  41 {
  42   const struct type_map_instance *inst = p;
  43
  44   return htab_hash_pointer (inst->type);
  45 }
  46
  47 /* Check two type_map_instance objects for equality.  */
  48
  49 static int
  50 eq_type_map_instance (const void *a, const void *b)
  51 {
  52   const struct type_map_instance *insta = a;
  53   const struct type_map_instance *instb = b;
  54
  55   return insta->type == instb->type;
  56 }
  57
  58 \f
  59
  60 /* Insert an entry into the type map associated with CONTEXT that maps
  61    from the gdb type TYPE to the gcc type GCC_TYPE.  It is ok for a
  62    given type to be inserted more than once, provided that the exact
  63    same association is made each time.  This simplifies how type
  64    caching works elsewhere in this file -- see how struct type caching
  65    is handled.  */
  66
  67 static void
  68 insert_type (struct compile_c_instance *context, struct type *type,
  69              gcc_type gcc_type)
  70 {
  71   struct type_map_instance inst, *add;
  72   void **slot;
  73
  74   inst.type = type;
  75   inst.gcc_type = gcc_type;
  76   slot = htab_find_slot (context->type_map, &inst, INSERT);
  77
  78   add = *slot;
  79   /* The type might have already been inserted in order to handle
  80      recursive types.  */
  81   gdb_assert (add == NULL || add->gcc_type == gcc_type);
  82
  83   if (add == NULL)
  84     {
  85       add = XNEW (struct type_map_instance);
  86       *add = inst;
  87       *slot = add;
  88     }
  89 }
  90
  91 /* Convert a pointer type to its gcc representation.  */
  92
  93 static gcc_type
  94 convert_pointer (struct compile_c_instance *context, struct type *type)
  95 {
  96   gcc_type target = convert_type (context, TYPE_TARGET_TYPE (type));
  97
  98   return C_CTX (context)->c_ops->build_pointer_type (C_CTX (context),
  99                                                      target);
 100 }
 101
 102 /* Convert an array type to its gcc representation.  */
 103
 104 static gcc_type
 105 convert_array (struct compile_c_instance *context, struct type *type)
 106 {
 107   gcc_type element_type;
 108   struct type *range = TYPE_INDEX_TYPE (type);
 109
 110   element_type = convert_type (context, TYPE_TARGET_TYPE (type));
 111
 112   if (TYPE_LOW_BOUND_KIND (range) != PROP_CONST)
 113     return C_CTX (context)->c_ops->error (C_CTX (context),
 114                                           _("array type with non-constant"
 115                                             " lower bound is not supported"));
 116   if (TYPE_LOW_BOUND (range) != 0)
 117     return C_CTX (context)->c_ops->error (C_CTX (context),
 118                                           _("cannot convert array type with "
 119                                             "non-zero lower bound to C"));
 120
 121   if (TYPE_HIGH_BOUND_KIND (range) == PROP_LOCEXPR
 122       || TYPE_HIGH_BOUND_KIND (range) == PROP_LOCLIST)
 123     {
 124       gcc_type result;
 125       char *upper_bound;
 126
 127       if (TYPE_VECTOR (type))
 128         return C_CTX (context)->c_ops->error (C_CTX (context),
 129                                               _("variably-sized vector type"
 130                                                 " is not supported"));
 131
 132       upper_bound = c_get_range_decl_name (&TYPE_RANGE_DATA (range)->high);
 133       result = C_CTX (context)->c_ops->build_vla_array_type (C_CTX (context),
 134                                                              element_type,
 135                                                              upper_bound);
 136       xfree (upper_bound);
 137       return result;
 138     }
 139   else
 140     {
 141       LONGEST low_bound, high_bound, count;
 142
 143       if (get_array_bounds (type, &low_bound, &high_bound) == 0)
 144         count = -1;
 145       else
 146         {
 147           gdb_assert (low_bound == 0); /* Ensured above.  */
 148           count = high_bound + 1;
 149         }
 150
 151       if (TYPE_VECTOR (type))
 152         return C_CTX (context)->c_ops->build_vector_type (C_CTX (context),
 153                                                           element_type,
 154                                                           count);
 155       return C_CTX (context)->c_ops->build_array_type (C_CTX (context),
 156                                                        element_type, count);
 157     }
 158 }
 159
 160 /* Convert a struct or union type to its gcc representation.  */
 161
 162 static gcc_type
 163 convert_struct_or_union (struct compile_c_instance *context, struct type *type)
 164 {
 165   int i;
 166   gcc_type result;
 167
 168   /* First we create the resulting type and enter it into our hash
 169      table.  This lets recursive types work.  */
 170   if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
 171     result = C_CTX (context)->c_ops->build_record_type (C_CTX (context));
 172   else
 173     {
 174       gdb_assert (TYPE_CODE (type) == TYPE_CODE_UNION);
 175       result = C_CTX (context)->c_ops->build_union_type (C_CTX (context));
 176     }
 177   insert_type (context, type, result);
 178
 179   for (i = 0; i < TYPE_NFIELDS (type); ++i)
 180     {
 181       gcc_type field_type;
 182       unsigned long bitsize = TYPE_FIELD_BITSIZE (type, i);
 183
 184       field_type = convert_type (context, TYPE_FIELD_TYPE (type, i));
 185       if (bitsize == 0)
 186         bitsize = 8 * TYPE_LENGTH (TYPE_FIELD_TYPE (type, i));
 187       C_CTX (context)->c_ops->build_add_field (C_CTX (context), result,
 188                                                TYPE_FIELD_NAME (type, i),
 189                                                field_type,
 190                                                bitsize,
 191                                                TYPE_FIELD_BITPOS (type, i));
 192     }
 193
 194   C_CTX (context)->c_ops->finish_record_or_union (C_CTX (context), result,
 195                                                   TYPE_LENGTH (type));
 196   return result;
 197 }
 198
 199 /* Convert an enum type to its gcc representation.  */
 200
 201 static gcc_type
 202 convert_enum (struct compile_c_instance *context, struct type *type)
 203 {
 204   gcc_type int_type, result;
 205   int i;
 206   struct gcc_c_context *ctx = C_CTX (context);
 207
 208   int_type = ctx->c_ops->int_type (ctx,
 209                                    TYPE_UNSIGNED (type),
 210                                    TYPE_LENGTH (type));
 211
 212   result = ctx->c_ops->build_enum_type (ctx, int_type);
 213   for (i = 0; i < TYPE_NFIELDS (type); ++i)
 214     {
 215       ctx->c_ops->build_add_enum_constant (ctx,
 216                                            result,
 217                                            TYPE_FIELD_NAME (type, i),
 218                                            TYPE_FIELD_ENUMVAL (type, i));
 219     }
 220
 221   ctx->c_ops->finish_enum_type (ctx, result);
 222
 223   return result;
 224 }
 225
 226 /* Convert a function type to its gcc representation.  */
 227
 228 static gcc_type
 229 convert_func (struct compile_c_instance *context, struct type *type)
 230 {
 231   int i;
 232   gcc_type result, return_type;
 233   struct gcc_type_array array;
 234   int is_varargs = TYPE_VARARGS (type) || !TYPE_PROTOTYPED (type);
 235
 236   /* This approach means we can't make self-referential function
 237      types.  Those are impossible in C, though.  */
 238   return_type = convert_type (context, TYPE_TARGET_TYPE (type));
 239
 240   array.n_elements = TYPE_NFIELDS (type);
 241   array.elements = XNEWVEC (gcc_type, TYPE_NFIELDS (type));
 242   for (i = 0; i < TYPE_NFIELDS (type); ++i)
 243     array.elements[i] = convert_type (context, TYPE_FIELD_TYPE (type, i));
 244
 245   result = C_CTX (context)->c_ops->build_function_type (C_CTX (context),
 246                                                         return_type,
 247                                                         &array, is_varargs);
 248   xfree (array.elements);
 249
 250   return result;
 251 }
 252
 253 /* Convert an integer type to its gcc representation.  */
 254
 255 static gcc_type
 256 convert_int (struct compile_c_instance *context, struct type *type)
 257 {
 258   return C_CTX (context)->c_ops->int_type (C_CTX (context),
 259                                            TYPE_UNSIGNED (type),
 260                                            TYPE_LENGTH (type));
 261 }
 262
 263 /* Convert a floating-point type to its gcc representation.  */
 264
 265 static gcc_type
 266 convert_float (struct compile_c_instance *context, struct type *type)
 267 {
 268   return C_CTX (context)->c_ops->float_type (C_CTX (context),
 269                                              TYPE_LENGTH (type));
 270 }
 271
 272 /* Convert the 'void' type to its gcc representation.  */
 273
 274 static gcc_type
 275 convert_void (struct compile_c_instance *context, struct type *type)
 276 {
 277   return C_CTX (context)->c_ops->void_type (C_CTX (context));
 278 }
 279
 280 /* Convert a boolean type to its gcc representation.  */
 281
 282 static gcc_type
 283 convert_bool (struct compile_c_instance *context, struct type *type)
 284 {
 285   return C_CTX (context)->c_ops->bool_type (C_CTX (context));
 286 }
 287
 288 /* Convert a qualified type to its gcc representation.  */
 289
 290 static gcc_type
 291 convert_qualified (struct compile_c_instance *context, struct type *type)
 292 {
 293   struct type *unqual = make_unqualified_type (type);
 294   gcc_type unqual_converted;
 295   int quals = 0;
 296
 297   unqual_converted = convert_type (context, unqual);
 298
 299   if (TYPE_CONST (type))
 300     quals |= GCC_QUALIFIER_CONST;
 301   if (TYPE_VOLATILE (type))
 302     quals |= GCC_QUALIFIER_VOLATILE;
 303   if (TYPE_RESTRICT (type))
 304     quals |= GCC_QUALIFIER_RESTRICT;
 305
 306   return C_CTX (context)->c_ops->build_qualified_type (C_CTX (context),
 307                                                        unqual_converted,
 308                                                        quals);
 309 }
 310
 311 /* Convert a complex type to its gcc representation.  */
 312
 313 static gcc_type
 314 convert_complex (struct compile_c_instance *context, struct type *type)
 315 {
 316   gcc_type base = convert_type (context, TYPE_TARGET_TYPE (type));
 317
 318   return C_CTX (context)->c_ops->build_complex_type (C_CTX (context), base);
 319 }
 320
 321 /* A helper function which knows how to convert most types from their
 322    gdb representation to the corresponding gcc form.  This examines
 323    the TYPE and dispatches to the appropriate conversion function.  It
 324    returns the gcc type.  */
 325
 326 static gcc_type
 327 convert_type_basic (struct compile_c_instance *context, struct type *type)
 328 {
 329   /* If we are converting a qualified type, first convert the
 330      unqualified type and then apply the qualifiers.  */
 331   if ((TYPE_INSTANCE_FLAGS (type) & (TYPE_INSTANCE_FLAG_CONST
 332                                      | TYPE_INSTANCE_FLAG_VOLATILE
 333                                      | TYPE_INSTANCE_FLAG_RESTRICT)) != 0)
 334     return convert_qualified (context, type);
 335
 336   switch (TYPE_CODE (type))
 337     {
 338     case TYPE_CODE_PTR:
 339       return convert_pointer (context, type);
 340
 341     case TYPE_CODE_ARRAY:
 342       return convert_array (context, type);
 343
 344     case TYPE_CODE_STRUCT:
 345     case TYPE_CODE_UNION:
 346       return convert_struct_or_union (context, type);
 347
 348     case TYPE_CODE_ENUM:
 349       return convert_enum (context, type);
 350
 351     case TYPE_CODE_FUNC:
 352       return convert_func (context, type);
 353
 354     case TYPE_CODE_INT:
 355       return convert_int (context, type);
 356
 357     case TYPE_CODE_FLT:
 358       return convert_float (context, type);
 359
 360     case TYPE_CODE_VOID:
 361       return convert_void (context, type);
 362
 363     case TYPE_CODE_BOOL:
 364       return convert_bool (context, type);
 365
 366     case TYPE_CODE_COMPLEX:
 367       return convert_complex (context, type);
 368     }
 369
 370   return C_CTX (context)->c_ops->error (C_CTX (context),
 371                                         _("cannot convert gdb type "
 372                                           "to gcc type"));
 373 }
 374
 375 /* See compile-internal.h.  */
 376
 377 gcc_type
 378 convert_type (struct compile_c_instance *context, struct type *type)
 379 {
 380   struct type_map_instance inst, *found;
 381   gcc_type result;
 382
 383   /* We don't ever have to deal with typedefs in this code, because
 384      those are only needed as symbols by the C compiler.  */
 385   CHECK_TYPEDEF (type);
 386
 387   inst.type = type;
 388   found = htab_find (context->type_map, &inst);
 389   if (found != NULL)
 390     return found->gcc_type;
 391
 392   result = convert_type_basic (context, type);
 393   insert_type (context, type, result);
 394   return result;
 395 }
 396
 397 \f
 398
 399 /* Delete the compiler instance C.  */
 400
 401 static void
 402 delete_instance (struct compile_instance *c)
 403 {
 404   struct compile_c_instance *context = (struct compile_c_instance *) c;
 405
 406   context->base.fe->ops->destroy (context->base.fe);
 407   htab_delete (context->type_map);
 408   if (context->symbol_err_map != NULL)
 409     htab_delete (context->symbol_err_map);
 410   xfree (context);
 411 }
 412
 413 /* See compile-internal.h.  */
 414
 415 struct compile_instance *
 416 new_compile_instance (struct gcc_c_context *fe)
 417 {
 418   struct compile_c_instance *result = XCNEW (struct compile_c_instance);
 419
 420   result->base.fe = &fe->base;
 421   result->base.destroy = delete_instance;
 422   result->base.gcc_target_options = ("-std=gnu11"
 423                                      /* Otherwise the .o file may need
 424                                         "_Unwind_Resume" and
 425                                         "__gcc_personality_v0".  */
 426                                      " -fno-exceptions");
 427
 428   result->type_map = htab_create_alloc (10, hash_type_map_instance,
 429                                         eq_type_map_instance,
 430                                         xfree, xcalloc, xfree);
 431
 432   fe->c_ops->set_callbacks (fe, gcc_convert_symbol,
 433                             gcc_symbol_address, result);
 434
 435   return &result->base;
 436 }