gcc/ada/gigi.h

   1 /****************************************************************************
   2  *                                                                          *
   3  *                         GNAT COMPILER COMPONENTS                         *
   4  *                                                                          *
   5  *                                 G I G I                                  *
   6  *                                                                          *
   7  *                              C Header File                               *
   8  *                                                                          *
   9  *                                                                          *
  10  *          Copyright (C) 1992-2002 Free Software Foundation, Inc.          *
  11  *                                                                          *
  12  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  13  * terms of the  GNU General Public License as published  by the Free Soft- *
  14  * ware  Foundation;  either version 2,  or (at your option) any later ver- *
  15  * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
  16  * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
  17  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License *
  18  * for  more details.  You should have  received  a copy of the GNU General *
  19  * Public License  distributed with GNAT;  see file COPYING.  If not, write *
  20  * to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, *
  21  * MA 02111-1307, USA.                                                      *
  22  *                                                                          *
  23  * As a  special  exception,  if you  link  this file  with other  files to *
  24  * produce an executable,  this file does not by itself cause the resulting *
  25  * executable to be covered by the GNU General Public License. This except- *
  26  * ion does not  however invalidate  any other reasons  why the  executable *
  27  * file might be covered by the  GNU Public License.                        *
  28  *                                                                          *
  29  * GNAT was originally developed  by the GNAT team at  New York University. *
  30  * It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). *
  31  *                                                                          *
  32  ****************************************************************************/
  33
  34 /* Declare all functions and types used by gigi.  */
  35
  36 /* See if DECL has an RTL that is indirect via a pseudo-register or a
  37    memory location and replace it with an indirect reference if so.
  38    This improves the debugger's ability to display the value.  */
  39 extern void adjust_decl_rtl     PARAMS ((tree));
  40
  41 /* Record the current code position in GNAT_NODE.  */
  42 extern void record_code_position PARAMS ((Node_Id));
  43
  44 /* Insert the code for GNAT_NODE at the position saved for that node.  */
  45 extern void insert_code_for     PARAMS ((Node_Id));
  46
  47 /* Routine called by gcc for emitting a stack check. GNU_EXPR is the
  48    expression that contains the last address on the stack to check. */
  49 extern tree emit_stack_check    PARAMS ((tree));
  50
  51 /* Make a TRANSFORM_EXPR to later expand GNAT_NODE into code.  */
  52 extern tree make_transform_expr PARAMS ((Node_Id));
  53
  54 /* Update the setjmp buffer BUF with the current stack pointer.  We assume
  55    here that a __builtin_setjmp was done to BUF.  */
  56 extern void update_setjmp_buf PARAMS ((tree));
  57
  58 /* GNU_TYPE is a type. Determine if it should be passed by reference by
  59    default.  */
  60 extern int default_pass_by_ref  PARAMS ((tree));
  61
  62 /* GNU_TYPE is the type of a subprogram parameter.  Determine from the type
  63    if it should be passed by reference.  */
  64 extern int must_pass_by_ref     PARAMS ((tree));
  65
  66 /* This function returns the version of GCC being used.  Here it's GCC 3.  */
  67 extern int gcc_version          PARAMS ((void));
  68
  69 /* Elaboration routines for the front end.  */
  70 extern void elab_all_gnat       PARAMS ((void));
  71
  72 /* Initialize DUMMY_NODE_TABLE.  */
  73 extern void init_dummy_type     PARAMS ((void));
  74
  75 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
  76    entity, this routine returns the equivalent GCC tree for that entity
  77    (an ..._DECL node) and associates the ..._DECL node with the input GNAT
  78    defining identifier.
  79
  80    If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
  81    initial value (in GCC tree form). This is optional for variables.
  82    For renamed entities, GNU_EXPR gives the object being renamed.
  83
  84    DEFINITION is nonzero if this call is intended for a definition.  This is
  85    used for separate compilation where it necessary to know whether an
  86    external declaration or a definition should be created if the GCC equivalent
  87    was not created previously.  The value of 1 is normally used for a non-zero
  88    DEFINITION, but a value of 2 is used in special circumstances, defined in
  89    the code.  */
  90 extern tree gnat_to_gnu_entity  PARAMS ((Entity_Id, tree, int));
  91
  92 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
  93    GCC type corresponding to that entity.  GNAT_ENTITY is assumed to
  94    refer to an Ada type.  */
  95 extern tree gnat_to_gnu_type    PARAMS ((Entity_Id));
  96
  97 /* Given GNAT_ENTITY, elaborate all expressions that are required to
  98    be elaborated at the point of its definition, but do nothing else.  */
  99 extern void elaborate_entity    PARAMS ((Entity_Id));
 100
 101 /* Mark GNAT_ENTITY as going out of scope at this point.  Recursively mark
 102    any entities on its entity chain similarly.  */
 103 extern void mark_out_of_scope   PARAMS ((Entity_Id));
 104
 105 /* Make a dummy type corresponding to GNAT_TYPE.  */
 106 extern tree make_dummy_type     PARAMS ((Entity_Id));
 107
 108 /* Get the unpadded version of a GNAT type.  */
 109 extern tree get_unpadded_type   PARAMS ((Entity_Id));
 110
 111 /* Called when we need to protect a variable object using a save_expr.  */
 112 extern tree maybe_variable      PARAMS ((tree, Node_Id));
 113
 114 /* Create a record type that contains a field of TYPE with a starting bit
 115    position so that it is aligned to ALIGN bits.  */
 116 /* Create a record type that contains a field of TYPE with a starting bit
 117    position so that it is aligned to ALIGN bits and is SIZE bytes long.  */
 118 extern tree make_aligning_type  PARAMS ((tree, int, tree));
 119
 120 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
 121    the value passed against the list of choices.  */
 122 extern tree choices_to_gnu      PARAMS ((tree, Node_Id));
 123
 124 /* Given a type T, a FIELD_DECL F, and a replacement value R,
 125    return a new type with all size expressions that contain F
 126    updated by replacing F with R.  This is identical to GCC's
 127    substitute_in_type except that it knows about TYPE_INDEX_TYPE.  */
 128 extern tree gnat_substitute_in_type PARAMS ((tree, tree, tree));
 129
 130 /* Return the "RM size" of GNU_TYPE.  This is the actual number of bits
 131    needed to represent the object.  */
 132 extern tree rm_size             PARAMS ((tree));
 133
 134 /* Given GNU_ID, an IDENTIFIER_NODE containing a name and SUFFIX, a
 135    string, return a new IDENTIFIER_NODE that is the concatenation of
 136    the name in GNU_ID and SUFFIX.  */
 137 extern tree concat_id_with_name PARAMS ((tree, const char *));
 138
 139 /* Return the name to be used for GNAT_ENTITY.  If a type, create a
 140    fully-qualified name, possibly with type information encoding.
 141    Otherwise, return the name.  */
 142 extern tree get_entity_name PARAMS ((Entity_Id));
 143
 144 /* Return a name for GNAT_ENTITY concatenated with two underscores and
 145    SUFFIX.  */
 146 extern tree create_concat_name PARAMS ((Entity_Id, const char *));
 147
 148 /* Flag indicating whether file names are discarded in exception messages */
 149 extern int discard_file_names;
 150
 151 /* If true, then gigi is being called on an analyzed but unexpanded
 152    tree, and the only purpose of the call is to properly annotate
 153    types with representation information */
 154 extern int type_annotate_only;
 155
 156 /* Current file name without path */
 157 extern const char *ref_filename;
 158
 159 /* List of TREE_LIST nodes representing a block stack.  TREE_VALUE
 160    of each gives the variable used for the setjmp buffer in the current
 161    block, if any.  */
 162 extern tree gnu_block_stack;
 163
 164 /* This is the main program of the back-end.  It sets up all the table
 165    structures and then generates code.  */
 166
 167 extern void gigi                PARAMS ((Node_Id, int, int, struct Node *,
 168                                          Node_Id *, Node_Id *,
 169                                          struct Elist_Header *,
 170                                          struct Elmt_Item *,
 171                                          struct String_Entry *,
 172                                          Char_Code *,
 173                                          struct List_Header *,
 174                                          Int, char *,
 175                                          Entity_Id, Entity_Id, Entity_Id,
 176                                          Int));
 177
 178 /* This function is the driver of the GNAT to GCC tree transformation process.
 179    GNAT_NODE is the root of some gnat tree.  It generates code for that
 180    part of the tree.  */
 181 extern void gnat_to_code        PARAMS ((Node_Id));
 182
 183 /* GNAT_NODE is the root of some GNAT tree.  Return the root of the
 184    GCC tree corresponding to that GNAT tree.  Normally, no code is generated;
 185    we just return an equivalent tree which is used elsewhere to generate
 186    code.  */
 187 extern tree gnat_to_gnu         PARAMS ((Node_Id));
 188
 189 /* Do the processing for the declaration of a GNAT_ENTITY, a type.  If
 190    a separate Freeze node exists, delay the bulk of the processing.  Otherwise
 191    make a GCC type for GNAT_ENTITY and set up the correspondance.  */
 192
 193 extern void process_type        PARAMS ((Entity_Id));
 194
 195 /* Determine the input_filename and the lineno from the source location
 196    (Sloc) of GNAT_NODE node.  Set the global variable input_filename and
 197    lineno.  If WRITE_NOTE_P is true, emit a line number note. */
 198 extern void set_lineno          PARAMS ((Node_Id, int));
 199
 200 /* Post an error message.  MSG is the error message, properly annotated.
 201    NODE is the node at which to post the error and the node to use for the
 202    "&" substitution.  */
 203 extern void post_error          PARAMS ((const char *, Node_Id));
 204
 205 /* Similar, but NODE is the node at which to post the error and ENT
 206    is the node to use for the "&" substitution.  */
 207 extern void post_error_ne       PARAMS ((const char *, Node_Id, Entity_Id));
 208
 209 /* Similar, but NODE is the node at which to post the error, ENT is the node
 210    to use for the "&" substitution, and N is the number to use for the ^.  */
 211 extern void post_error_ne_num   PARAMS ((const char *, Node_Id, Entity_Id,
 212                                          int));
 213
 214 /* Similar to post_error_ne_num, but T is a GCC tree representing the number
 215    to write.  If the tree represents a constant that fits within a
 216    host integer, the text inside curly brackets in MSG will be output
 217    (presumably including a '^').  Otherwise that text will not be output
 218    and the text inside square brackets will be output instead.  */
 219 extern void post_error_ne_tree  PARAMS ((const char *, Node_Id, Entity_Id,
 220                                          tree));
 221
 222 /* Similar to post_error_ne_tree, except that NUM is a second
 223    integer to write in the message.  */
 224 extern void post_error_ne_tree_2 PARAMS ((const char *, Node_Id, Entity_Id,
 225                                           tree, int));
 226
 227 /* Set the node for a second '&' in the error message.  */
 228 extern void set_second_error_entity PARAMS ((Entity_Id));
 229
 230 /* Protect EXP from multiple evaluation.  This may make a SAVE_EXPR.  */
 231 extern tree protect_multiple_eval PARAMS ((tree));
 232
 233 /* Signal abort, with "Gigi abort" as the error label, and error_gnat_node
 234    as the relevant node that provides the location info for the error.
 235    The single parameter CODE is an integer code that is included in the
 236    additional error message generated. */
 237 extern void gigi_abort          PARAMS ((int)) ATTRIBUTE_NORETURN;
 238
 239 /* Initialize the table that maps GNAT codes to GCC codes for simple
 240    binary and unary operations.  */
 241 extern void init_code_table     PARAMS ((void));
 242
 243 /* Current node being treated, in case gigi_abort or Check_Elaboration_Code
 244    called.  */
 245 extern Node_Id error_gnat_node;
 246
 247 /* This is equivalent to stabilize_reference in GCC's tree.c, but we know
 248    how to handle our new nodes and we take an extra argument that says
 249    whether to force evaluation of everything.  */
 250
 251 extern tree gnat_stabilize_reference PARAMS ((tree, int));
 252
 253 /* Highest number in the front-end node table.  */
 254 extern int max_gnat_nodes;
 255
 256 /* If nonzero, pretend we are allocating at global level.  */
 257 extern int force_global;
 258
 259 /* Standard data type sizes.  Most of these are not used.  */
 260
 261 #ifndef CHAR_TYPE_SIZE
 262 #define CHAR_TYPE_SIZE BITS_PER_UNIT
 263 #endif
 264
 265 #ifndef SHORT_TYPE_SIZE
 266 #define SHORT_TYPE_SIZE (BITS_PER_UNIT * MIN ((UNITS_PER_WORD + 1) / 2, 2))
 267 #endif
 268
 269 #ifndef INT_TYPE_SIZE
 270 #define INT_TYPE_SIZE BITS_PER_WORD
 271 #endif
 272
 273 #ifndef LONG_TYPE_SIZE
 274 #define LONG_TYPE_SIZE BITS_PER_WORD
 275 #endif
 276
 277 #ifndef LONG_LONG_TYPE_SIZE
 278 #define LONG_LONG_TYPE_SIZE (BITS_PER_WORD * 2)
 279 #endif
 280
 281 #ifndef FLOAT_TYPE_SIZE
 282 #define FLOAT_TYPE_SIZE BITS_PER_WORD
 283 #endif
 284
 285 #ifndef DOUBLE_TYPE_SIZE
 286 #define DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
 287 #endif
 288
 289 #ifndef LONG_DOUBLE_TYPE_SIZE
 290 #define LONG_DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
 291 #endif
 292
 293 /* The choice of SIZE_TYPE here is very problematic.  We need a signed
 294    type whose bit width is Pmode.  Assume "long" is such a type here.  */
 295 #undef SIZE_TYPE
 296 #define SIZE_TYPE "long int"
 297
 298 \f
 299 /* Data structures used to represent attributes.  */
 300
 301 enum attr_type {ATTR_MACHINE_ATTRIBUTE, ATTR_LINK_ALIAS,
 302                 ATTR_LINK_SECTION, ATTR_WEAK_EXTERNAL};
 303
 304 struct attrib
 305 {
 306   struct attrib *next;
 307   enum attr_type type;
 308   tree name;
 309   tree arg;
 310   Node_Id error_point;
 311 };
 312
 313 /* Define the entries in the standard data array.  */
 314 enum standard_datatypes
 315 {
 316 /* Various standard data types and nodes.  */
 317   ADT_longest_float_type,
 318   ADT_void_type_decl,
 319
 320   /* The type of an exception.  */
 321   ADT_except_type,
 322
 323   /* Type declaration node  <==> typedef void *T */
 324   ADT_ptr_void_type,
 325
 326   /* Function type declaration -- void T() */
 327   ADT_void_ftype,
 328
 329   /* Type declaration node  <==> typedef void *T() */
 330   ADT_ptr_void_ftype,
 331
 332   /* A function declaration node for a run-time function for allocating memory.
 333      Ada allocators cause calls to this function to be generated.   */
 334   ADT_malloc_decl,
 335
 336   /* Likewise for freeing memory.  */
 337   ADT_free_decl,
 338
 339   /* Types and decls used by our temporary exception mechanism.  See
 340      init_gigi_decls for details.  */
 341   ADT_jmpbuf_type,
 342   ADT_jmpbuf_ptr_type,
 343   ADT_get_jmpbuf_decl,
 344   ADT_set_jmpbuf_decl,
 345   ADT_get_excptr_decl,
 346   ADT_setjmp_decl,
 347   ADT_longjmp_decl,
 348   ADT_raise_nodefer_decl,
 349   ADT_LAST};
 350
 351 extern tree gnat_std_decls[(int) ADT_LAST];
 352 extern tree gnat_raise_decls[(int) LAST_REASON_CODE + 1];
 353
 354 #define longest_float_type_node gnat_std_decls[(int) ADT_longest_float_type]
 355 #define void_type_decl_node gnat_std_decls[(int) ADT_void_type_decl]
 356 #define except_type_node gnat_std_decls[(int) ADT_except_type]
 357 #define ptr_void_type_node gnat_std_decls[(int) ADT_ptr_void_type]
 358 #define void_ftype gnat_std_decls[(int) ADT_void_ftype]
 359 #define ptr_void_ftype gnat_std_decls[(int) ADT_ptr_void_ftype]
 360 #define malloc_decl gnat_std_decls[(int) ADT_malloc_decl]
 361 #define free_decl gnat_std_decls[(int) ADT_free_decl]
 362 #define jmpbuf_type gnat_std_decls[(int) ADT_jmpbuf_type]
 363 #define jmpbuf_ptr_type gnat_std_decls[(int) ADT_jmpbuf_ptr_type]
 364 #define get_jmpbuf_decl gnat_std_decls[(int) ADT_get_jmpbuf_decl]
 365 #define set_jmpbuf_decl gnat_std_decls[(int) ADT_set_jmpbuf_decl]
 366 #define get_excptr_decl gnat_std_decls[(int) ADT_get_excptr_decl]
 367 #define setjmp_decl gnat_std_decls[(int) ADT_setjmp_decl]
 368 #define longjmp_decl gnat_std_decls[(int) ADT_longjmp_decl]
 369 #define raise_nodefer_decl gnat_std_decls[(int) ADT_raise_nodefer_decl]
 370
 371 /* Routines expected by the gcc back-end. They must have exactly the same
 372    prototype and names as below.  */
 373
 374 /* Returns non-zero if we are currently in the global binding level       */
 375 extern int global_bindings_p            PARAMS ((void));
 376
 377 /* Returns the list of declarations in the current level. Note that this list
 378    is in reverse order (it has to be so for back-end compatibility).  */
 379 extern tree getdecls                    PARAMS ((void));
 380
 381 /* Nonzero if the current level needs to have a BLOCK made.  */
 382 extern int kept_level_p                 PARAMS ((void));
 383
 384 /* Enter a new binding level. The input parameter is ignored, but has to be
 385    specified for back-end compatibility.  */
 386 extern void pushlevel                   PARAMS ((int));
 387
 388 /* Exit a binding level.
 389    Pop the level off, and restore the state of the identifier-decl mappings
 390    that were in effect when this level was entered.
 391
 392    If KEEP is nonzero, this level had explicit declarations, so
 393    and create a "block" (a BLOCK node) for the level
 394    to record its declarations and subblocks for symbol table output.
 395
 396    If FUNCTIONBODY is nonzero, this level is the body of a function,
 397    so create a block as if KEEP were set and also clear out all
 398    label names.
 399
 400    If REVERSE is nonzero, reverse the order of decls before putting
 401    them into the BLOCK.  */
 402 extern tree poplevel                    PARAMS ((int,int, int));
 403
 404 /* Insert BLOCK at the end of the list of subblocks of the
 405    current binding level.  This is used when a BIND_EXPR is expanded,
 406    to handle the BLOCK node inside the BIND_EXPR.  */
 407 extern void insert_block                PARAMS ((tree));
 408
 409 /* Set the BLOCK node for the innermost scope
 410    (the one we are currently in).  */
 411 extern void set_block                   PARAMS ((tree));
 412
 413 /* Records a ..._DECL node DECL as belonging to the current lexical scope.
 414    Returns the ..._DECL node. */
 415 extern tree pushdecl                    PARAMS ((tree));
 416
 417 /* Create the predefined scalar types such as `integer_type_node' needed
 418    in the gcc back-end and initialize the global binding level.  */
 419 extern void gnat_init_decl_processing   PARAMS ((void));
 420 extern void init_gigi_decls             PARAMS ((tree, tree));
 421 extern void gnat_init_gcc_eh            PARAMS ((void));
 422
 423 /* Return an integer type with the number of bits of precision given by
 424    PRECISION.  UNSIGNEDP is nonzero if the type is unsigned; otherwise
 425    it is a signed type.  */
 426 extern tree gnat_type_for_size          PARAMS ((unsigned, int));
 427
 428 /* Return a data type that has machine mode MODE.  UNSIGNEDP selects
 429    an unsigned type; otherwise a signed type is returned.  */
 430 extern tree gnat_type_for_mode          PARAMS ((enum machine_mode, int));
 431
 432 /* Return the unsigned version of a TYPE_NODE, a scalar type.  */
 433 extern tree gnat_unsigned_type          PARAMS ((tree));
 434
 435 /* Return the signed version of a TYPE_NODE, a scalar type.  */
 436 extern tree gnat_signed_type            PARAMS ((tree));
 437
 438 /* Return a type the same as TYPE except unsigned or signed according to
 439    UNSIGNEDP.  */
 440 extern tree gnat_signed_or_unsigned_type PARAMS ((int, tree));
 441
 442 /* This function is called indirectly from toplev.c to handle incomplete
 443    declarations, i.e. VAR_DECL nodes whose DECL_SIZE is zero.  To be precise,
 444    compile_file in toplev.c makes an indirect call through the function pointer
 445    incomplete_decl_finalize_hook which is initialized to this routine in
 446    init_decl_processing.  */
 447 extern void gnat_finish_incomplete_decl PARAMS ((tree));
 448
 449 /* Create an expression whose value is that of EXPR,
 450    converted to type TYPE.  The TREE_TYPE of the value
 451    is always TYPE.  This function implements all reasonable
 452    conversions; callers should filter out those that are
 453    not permitted by the language being compiled.  */
 454 extern tree convert                     PARAMS ((tree, tree));
 455
 456 /* Routines created solely for the tree translator's sake. Their prototypes
 457    can be changed as desired.  */
 458
 459 /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
 460    GNU_DECL is the GCC tree which is to be associated with
 461    GNAT_ENTITY. Such gnu tree node is always an ..._DECL node.
 462    If NO_CHECK is nonzero, the latter check is suppressed.
 463    If GNU_DECL is zero, a previous association is to be reset.  */
 464 extern void save_gnu_tree               PARAMS ((Entity_Id, tree, int));
 465
 466 /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
 467    Return the ..._DECL node that was associated with it.  If there is no tree
 468    node associated with GNAT_ENTITY, abort.  */
 469 extern tree get_gnu_tree                PARAMS ((Entity_Id));
 470
 471 /* Return nonzero if a GCC tree has been associated with GNAT_ENTITY.  */
 472 extern int present_gnu_tree             PARAMS ((Entity_Id));
 473
 474 /* Initialize tables for above routines.  */
 475 extern void init_gnat_to_gnu            PARAMS ((void));
 476
 477 /* Given a record type (RECORD_TYPE) and a chain of FIELD_DECL
 478    nodes (FIELDLIST), finish constructing the record or union type.
 479    If HAS_REP is nonzero, this record has a rep clause; don't call
 480    layout_type but merely set the size and alignment ourselves.
 481    If DEFER_DEBUG is nonzero, do not call the debugging routines
 482    on this type; it will be done later. */
 483 extern void finish_record_type          PARAMS ((tree, tree, int, int));
 484
 485 /* Returns a FUNCTION_TYPE node. RETURN_TYPE is the type returned by the
 486    subprogram. If it is void_type_node, then we are dealing with a procedure,
 487    otherwise we are dealing with a function. PARAM_DECL_LIST is a list of
 488    PARM_DECL nodes that are the subprogram arguments.  CICO_LIST is the
 489    copy-in/copy-out list to be stored into TYPE_CI_CO_LIST.
 490    RETURNS_UNCONSTRAINED is nonzero if the function returns an unconstrained
 491    object.  RETURNS_BY_REF is nonzero if the function returns by reference.
 492    RETURNS_WITH_DSP is nonzero if the function is to return with a
 493    depressed stack pointer.  */
 494 extern tree create_subprog_type         PARAMS ((tree, tree, tree, int, int,
 495                                                  int));
 496
 497 /* Return a copy of TYPE, but safe to modify in any way.  */
 498 extern tree copy_type                   PARAMS ((tree));
 499
 500 /* Return an INTEGER_TYPE of SIZETYPE with range MIN to MAX and whose
 501    TYPE_INDEX_TYPE is INDEX.  */
 502 extern tree create_index_type           PARAMS ((tree, tree, tree));
 503
 504 /* Return a TYPE_DECL node. TYPE_NAME gives the name of the type (a character
 505    string) and TYPE is a ..._TYPE node giving its data type.
 506    ARTIFICIAL_P is nonzero if this is a declaration that was generated
 507    by the compiler.  DEBUG_INFO_P is nonzero if we need to write debugging
 508    information about this type.  */
 509 extern tree create_type_decl            PARAMS ((tree, tree, struct attrib *,
 510                                                  int, int));
 511
 512 /* Returns a GCC VAR_DECL node. VAR_NAME gives the name of the variable.
 513    ASM_NAME is its assembler name (if provided).  TYPE is
 514    its data type (a GCC ..._TYPE node).  VAR_INIT is the GCC tree for an
 515    optional initial expression; NULL_TREE if none.
 516
 517    CONST_FLAG is nonzero if this variable is constant.
 518
 519    PUBLIC_FLAG is nonzero if this definition is to be made visible outside of
 520    the current compilation unit. This flag should be set when processing the
 521    variable definitions in a package specification.  EXTERN_FLAG is nonzero
 522    when processing an external variable declaration (as opposed to a
 523    definition: no storage is to be allocated for the variable here).
 524    STATIC_FLAG is only relevant when not at top level.  In that case
 525    it indicates whether to always allocate storage to the variable.  */
 526 extern tree create_var_decl             PARAMS ((tree, tree, tree, tree, int,
 527                                                  int, int, int,
 528                                                  struct attrib *));
 529
 530 /* Given a DECL and ATTR_LIST, apply the listed attributes.  */
 531 extern void process_attributes          PARAMS ((tree, struct attrib *));
 532
 533 /* Obtain any pending elaborations and clear the old list.  */
 534 extern tree get_pending_elaborations    PARAMS ((void));
 535
 536 /* Return nonzero if there are pending elaborations.  */
 537 extern int pending_elaborations_p       PARAMS ((void));
 538
 539 /* Save a copy of the current pending elaboration list and make a new
 540    one.  */
 541 extern void push_pending_elaborations   PARAMS ((void));
 542
 543 /* Pop the stack of pending elaborations.  */
 544 extern void pop_pending_elaborations    PARAMS ((void));
 545
 546 /* Return the current position in pending_elaborations so we can insert
 547    elaborations after that point.  */
 548 extern tree get_elaboration_location    PARAMS ((void));
 549
 550 /* Insert the current elaborations after ELAB, which is in some elaboration
 551    list.  */
 552 extern void insert_elaboration_list     PARAMS ((tree));
 553
 554 /* Add some pending elaborations to the current list.  */
 555 extern void add_pending_elaborations    PARAMS ((tree, tree));
 556
 557 /* Returns a FIELD_DECL node. FIELD_NAME the field name, FIELD_TYPE is its
 558    type, and RECORD_TYPE is the type of the parent.  PACKED is nonzero if
 559    this field is in a record type with a "pragma pack".  If SIZE is nonzero
 560    it is the specified size for this field.  If POS is nonzero, it is the bit
 561    position.  If ADDRESSABLE is nonzero, it means we are allowed to take
 562    the address of this field for aliasing purposes.  */
 563 extern tree create_field_decl           PARAMS ((tree, tree, tree, int,
 564                                                  tree, tree, int));
 565
 566 /* Returns a PARM_DECL node. PARAM_NAME is the name of the parameter,
 567    PARAM_TYPE is its type.  READONLY is nonzero if the parameter is
 568    readonly (either an IN parameter or an address of a pass-by-ref
 569    parameter). */
 570 extern tree create_param_decl           PARAMS ((tree, tree, int));
 571
 572 /* Returns a FUNCTION_DECL node.  SUBPROG_NAME is the name of the subprogram,
 573    ASM_NAME is its assembler name, SUBPROG_TYPE is its type (a FUNCTION_TYPE
 574    node), PARAM_DECL_LIST is the list of the subprogram arguments (a list of
 575    PARM_DECL nodes chained through the TREE_CHAIN field).
 576
 577    INLINE_FLAG, PUBLIC_FLAG, and EXTERN_FLAG are used to set the appropriate
 578    fields in the FUNCTION_DECL.  */
 579 extern tree create_subprog_decl         PARAMS ((tree, tree, tree, tree, int,
 580                                                  int, int, struct attrib *));
 581
 582 /* Returns a LABEL_DECL node for LABEL_NAME.  */
 583 extern tree create_label_decl           PARAMS ((tree));
 584
 585 /* Set up the framework for generating code for SUBPROG_DECL, a subprogram
 586    body. This routine needs to be invoked before processing the declarations
 587    appearing in the subprogram.  */
 588 extern void begin_subprog_body          PARAMS ((tree));
 589
 590 /* Finish the definition of the current subprogram and compile it all the way
 591    to assembler language output.  */
 592 extern void end_subprog_body            PARAMS ((void));
 593
 594 /* Build a template of type TEMPLATE_TYPE from the array bounds of ARRAY_TYPE.
 595    EXPR is an expression that we can use to locate any PLACEHOLDER_EXPRs.
 596    Return a constructor for the template.  */
 597 extern tree build_template              PARAMS ((tree, tree, tree));
 598
 599 /* Build a VMS descriptor from a Mechanism_Type, which must specify
 600    a descriptor type, and the GCC type of an object.  Each FIELD_DECL
 601    in the type contains in its DECL_INITIAL the expression to use when
 602    a constructor is made for the type.  GNAT_ENTITY is a gnat node used
 603    to print out an error message if the mechanism cannot be applied to
 604    an object of that type and also for the name.  */
 605
 606 extern tree build_vms_descriptor        PARAMS ((tree, Mechanism_Type,
 607                                                  Entity_Id));
 608
 609 /* Build a type to be used to represent an aliased object whose nominal
 610    type is an unconstrained array.  This consists of a RECORD_TYPE containing
 611    a field of TEMPLATE_TYPE and a field of OBJECT_TYPE, which is an
 612    ARRAY_TYPE.  If ARRAY_TYPE is that of the unconstrained array, this
 613    is used to represent an arbitrary unconstrained object.  Use NAME
 614    as the name of the record.  */
 615 extern tree build_unc_object_type       PARAMS ((tree, tree, tree));
 616
 617 /* Update anything previously pointing to OLD_TYPE to point to NEW_TYPE.  In
 618    the normal case this is just two adjustments, but we have more to do
 619    if NEW is an UNCONSTRAINED_ARRAY_TYPE.  */
 620 extern void update_pointer_to           PARAMS ((tree, tree));
 621
 622 /* EXP is an expression for the size of an object.  If this size contains
 623    discriminant references, replace them with the maximum (if MAX_P) or
 624    minimum (if ! MAX_P) possible value of the discriminant.  */
 625 extern tree max_size                    PARAMS ((tree, int));
 626
 627 /* Remove all conversions that are done in EXP.  This includes converting
 628    from a padded type or to a left-justified modular type.  If TRUE_ADDRESS
 629    is nonzero, always return the address of the containing object even if
 630    the address is not bit-aligned.  */
 631 extern tree remove_conversions          PARAMS ((tree, int));
 632
 633 /* If EXP's type is an UNCONSTRAINED_ARRAY_TYPE, return an expression that
 634    refers to the underlying array.  If its type has TYPE_CONTAINS_TEMPLATE_P,
 635    likewise return an expression pointing to the underlying array.  */
 636 extern tree maybe_unconstrained_array   PARAMS ((tree));
 637
 638 /* Return an expression that does an unchecked converstion of EXPR to TYPE.  */
 639 extern tree unchecked_convert           PARAMS ((tree, tree));
 640
 641 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR or other logical
 642    operation.
 643
 644    This preparation consists of taking the ordinary
 645    representation of an expression expr and producing a valid tree
 646    boolean expression describing whether expr is nonzero.  We could
 647    simply always do build_binary_op (NE_EXPR, expr, integer_zero_node, 1),
 648    but we optimize comparisons, &&, ||, and !.
 649
 650    The resulting type should always be the same as the input type.
 651    This function is simpler than the corresponding C version since
 652    the only possible operands will be things of Boolean type.  */
 653 extern tree gnat_truthvalue_conversion      PARAMS((tree));
 654
 655 /* Return the base type of TYPE.  */
 656 extern tree get_base_type       PARAMS((tree));
 657
 658 /* Likewise, but only return types known at Ada source.  */
 659 extern tree get_ada_base_type   PARAMS((tree));
 660
 661 /* EXP is a GCC tree representing an address.  See if we can find how
 662    strictly the object at that address is aligned.   Return that alignment
 663    strictly the object at that address is aligned.   Return that alignment
 664    in bits.  If we don't know anything about the alignment, return 0.  */
 665 extern unsigned int known_alignment     PARAMS((tree));
 666
 667 /* Make a binary operation of kind OP_CODE.  RESULT_TYPE is the type
 668    desired for the result.  Usually the operation is to be performed
 669    in that type.  For MODIFY_EXPR and ARRAY_REF, RESULT_TYPE may be 0
 670    in which case the type to be used will be derived from the operands.  */
 671 extern tree build_binary_op     PARAMS((enum tree_code, tree, tree, tree));
 672
 673 /* Similar, but make unary operation.   */
 674 extern tree build_unary_op      PARAMS((enum tree_code, tree, tree));
 675
 676 /* Similar, but for COND_EXPR.  */
 677 extern tree build_cond_expr     PARAMS((tree, tree, tree, tree));
 678
 679 /* Build a CALL_EXPR to call FUNDECL with one argument, ARG.  Return
 680    the CALL_EXPR.  */
 681 extern tree build_call_1_expr   PARAMS((tree, tree));
 682
 683 /* Build a CALL_EXPR to call FUNDECL with two argument, ARG1 & ARG2.  Return
 684    the CALL_EXPR.  */
 685 extern tree build_call_2_expr   PARAMS((tree, tree, tree));
 686
 687 /* Likewise to call FUNDECL with no arguments.  */
 688 extern tree build_call_0_expr   PARAMS((tree));
 689
 690 /* Call a function that raises an exception and pass the line number and file
 691    name, if requested.  MSG says which exception function to call.  */
 692 extern tree build_call_raise    PARAMS((int));
 693
 694 /* Return a CONSTRUCTOR of TYPE whose list is LIST.  */
 695 extern tree build_constructor   PARAMS((tree, tree));
 696
 697 /* Return a COMPONENT_REF to access a field that is given by COMPONENT,
 698    an IDENTIFIER_NODE giving the name of the field, FIELD, a FIELD_DECL,
 699    for the field, or both.  */
 700 extern tree build_component_ref PARAMS((tree, tree, tree));
 701
 702 /* Build a GCC tree to call an allocation or deallocation function.
 703    If GNU_OBJ is nonzero, it is an object to deallocate.  Otherwise,
 704    genrate an allocator.
 705
 706    GNU_SIZE is the size of the object and ALIGN is the alignment.
 707    GNAT_PROC, if present is a procedure to call and GNAT_POOL is the
 708    storage pool to use.  If not preset, malloc and free will be used.  */
 709 extern tree build_call_alloc_dealloc PARAMS((tree, tree, int, Entity_Id,
 710                                              Entity_Id));
 711
 712 /* Build a GCC tree to correspond to allocating an object of TYPE whose
 713    initial value if INIT, if INIT is nonzero.  Convert the expression to
 714    RESULT_TYPE, which must be some type of pointer.  Return the tree.
 715    GNAT_PROC and GNAT_POOL optionally give the procedure to call and
 716    the storage pool to use.  */
 717 extern tree build_allocator     PARAMS((tree, tree, tree, Entity_Id,
 718                                         Entity_Id));
 719
 720 /* Fill in a VMS descriptor for EXPR and return a constructor for it.
 721    GNAT_FORMAL is how we find the descriptor record.  */
 722
 723 extern tree fill_vms_descriptor PARAMS((tree, Entity_Id));
 724
 725 /* Indicate that we need to make the address of EXPR_NODE and it therefore
 726    should not be allocated in a register.  Return true if successful.  */
 727 extern bool gnat_mark_addressable PARAMS((tree));
 728
 729 /* These functions return the basic data type sizes and related parameters
 730    about the target machine.  */
 731
 732 extern Pos get_target_bits_per_unit             PARAMS ((void));
 733 extern Pos get_target_bits_per_word             PARAMS ((void));
 734 extern Pos get_target_char_size                 PARAMS ((void));
 735 extern Pos get_target_wchar_t_size              PARAMS ((void));
 736 extern Pos get_target_short_size                PARAMS ((void));
 737 extern Pos get_target_int_size                  PARAMS ((void));
 738 extern Pos get_target_long_size                 PARAMS ((void));
 739 extern Pos get_target_long_long_size            PARAMS ((void));
 740 extern Pos get_target_float_size                PARAMS ((void));
 741 extern Pos get_target_double_size               PARAMS ((void));
 742 extern Pos get_target_long_double_size          PARAMS ((void));
 743 extern Pos get_target_pointer_size              PARAMS ((void));
 744 extern Pos get_target_maximum_alignment         PARAMS ((void));
 745 extern Boolean get_target_no_dollar_in_label    PARAMS ((void));
 746 extern Nat get_float_words_be                   PARAMS ((void));
 747 extern Nat get_words_be                         PARAMS ((void));
 748 extern Nat get_bytes_be                         PARAMS ((void));
 749 extern Nat get_bits_be                          PARAMS ((void));
 750 extern Nat get_strict_alignment                 PARAMS ((void));