gcc/ada/gigi.h

   1 /****************************************************************************
   2  *                                                                          *
   3  *                         GNAT COMPILER COMPONENTS                         *
   4  *                                                                          *
   5  *                                 G I G I                                  *
   6  *                                                                          *
   7  *                              C Header File                               *
   8  *                                                                          *
   9  *          Copyright (C) 1992-2004 Free Software Foundation, Inc.          *
  10  *                                                                          *
  11  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  12  * terms of the  GNU General Public License as published  by the Free Soft- *
  13  * ware  Foundation;  either version 2,  or (at your option) any later ver- *
  14  * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
  15  * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
  16  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License *
  17  * for  more details.  You should have  received  a copy of the GNU General *
  18  * Public License  distributed with GNAT;  see file COPYING.  If not, write *
  19  * to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, *
  20  * MA 02111-1307, USA.                                                      *
  21  *                                                                          *
  22  * As a  special  exception,  if you  link  this file  with other  files to *
  23  * produce an executable,  this file does not by itself cause the resulting *
  24  * executable to be covered by the GNU General Public License. This except- *
  25  * ion does not  however invalidate  any other reasons  why the  executable *
  26  * file might be covered by the  GNU Public License.                        *
  27  *                                                                          *
  28  * GNAT was originally developed  by the GNAT team at  New York University. *
  29  * Extensive contributions were provided by Ada Core Technologies Inc.      *
  30  *                                                                          *
  31  ****************************************************************************/
  32
  33 /* The largest alignment, in bits, that is needed for using the widest
  34    move instruction.  */
  35 extern unsigned int largest_move_alignment;
  36
  37 /* Declare all functions and types used by gigi.  */
  38
  39 /* See if DECL has an RTL that is indirect via a pseudo-register or a
  40    memory location and replace it with an indirect reference if so.
  41    This improves the debugger's ability to display the value.  */
  42 extern void adjust_decl_rtl (tree);
  43
  44 /* Record the current code position in GNAT_NODE.  */
  45 extern void record_code_position (Node_Id);
  46
  47 /* Insert the code for GNAT_NODE at the position saved for that node.  */
  48 extern void insert_code_for (Node_Id);
  49
  50 /* Compute the alignment of the largest mode that can be used for copying
  51    objects.  */
  52 extern void gnat_compute_largest_alignment (void);
  53
  54 /* Routine called by gcc for emitting a stack check. GNU_EXPR is the
  55    expression that contains the last address on the stack to check. */
  56 extern tree emit_stack_check (tree);
  57
  58 /* Make a TRANSFORM_EXPR to later expand GNAT_NODE into code.  */
  59 extern tree make_transform_expr (Node_Id);
  60
  61 /* GNU_TYPE is a type. Determine if it should be passed by reference by
  62    default.  */
  63 extern int default_pass_by_ref (tree);
  64
  65 /* GNU_TYPE is the type of a subprogram parameter.  Determine from the type
  66    if it should be passed by reference.  */
  67 extern int must_pass_by_ref (tree);
  68
  69 /* Elaboration routines for the front end.  */
  70 extern void elab_all_gnat (void);
  71
  72 /* Initialize DUMMY_NODE_TABLE.  */
  73 extern void init_dummy_type (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 (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 (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 (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 (Entity_Id);
 104
 105 /* Make a dummy type corresponding to GNAT_TYPE.  */
 106 extern tree make_dummy_type (Entity_Id);
 107
 108 /* Get the unpadded version of a GNAT type.  */
 109 extern tree get_unpadded_type (Entity_Id);
 110
 111 /* Called when we need to protect a variable object using a save_expr.  */
 112 extern tree maybe_variable (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 (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 (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 (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 (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 (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 (Entity_Id);
 143
 144 /* Return a name for GNAT_ENTITY concatenated with two underscores and
 145    SUFFIX.  */
 146 extern tree create_concat_name (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 GTY(()) 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 (Node_Id, int, int, struct Node *, Node_Id *, Node_Id *,
 168                   struct Elist_Header *, struct Elmt_Item *,
 169                   struct String_Entry *, Char_Code *, struct List_Header *,
 170                   Int, char *, Entity_Id, Entity_Id, Entity_Id, Int);
 171
 172 /* This function is the driver of the GNAT to GCC tree transformation process.
 173    GNAT_NODE is the root of some gnat tree.  It generates code for that
 174    part of the tree.  */
 175 extern void gnat_to_code (Node_Id);
 176
 177 /* GNAT_NODE is the root of some GNAT tree.  Return the root of the
 178    GCC tree corresponding to that GNAT tree.  Normally, no code is generated;
 179    we just return an equivalent tree which is used elsewhere to generate
 180    code.  */
 181 extern tree gnat_to_gnu (Node_Id);
 182
 183 /* GNU_STMT is a statement.  We generate code for that statement.  */
 184 extern void gnat_expand_stmt (tree);
 185
 186 /* Do the processing for the declaration of a GNAT_ENTITY, a type.  If
 187    a separate Freeze node exists, delay the bulk of the processing.  Otherwise
 188    make a GCC type for GNAT_ENTITY and set up the correspondance.  */
 189
 190 extern void process_type (Entity_Id);
 191
 192 /* Determine the input_filename and the input_line from the source location
 193    (Sloc) of GNAT_NODE node.  Set the global variable input_filename and
 194    input_line.  If WRITE_NOTE_P is true, emit a line number note. */
 195 extern void set_lineno (Node_Id, int);
 196
 197 /* Likewise, but passed a Sloc.  */
 198 extern void set_lineno_from_sloc (Source_Ptr, 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 (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 (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 (const char *, Node_Id, Entity_Id, int);
 212
 213 /* Similar to post_error_ne_num, but T is a GCC tree representing the number
 214    to write.  If the tree represents a constant that fits within a
 215    host integer, the text inside curly brackets in MSG will be output
 216    (presumably including a '^').  Otherwise that text will not be output
 217    and the text inside square brackets will be output instead.  */
 218 extern void post_error_ne_tree (const char *, Node_Id, Entity_Id, tree);
 219
 220 /* Similar to post_error_ne_tree, except that NUM is a second
 221    integer to write in the message.  */
 222 extern void post_error_ne_tree_2 (const char *, Node_Id, Entity_Id, tree, int);
 223
 224 /* Set the node for a second '&' in the error message.  */
 225 extern void set_second_error_entity (Entity_Id);
 226
 227 /* Protect EXP from multiple evaluation.  This may make a SAVE_EXPR.  */
 228 extern tree protect_multiple_eval (tree);
 229
 230 /* Signal abort, with "Gigi abort" as the error label, and error_gnat_node
 231    as the relevant node that provides the location info for the error.
 232    The single parameter CODE is an integer code that is included in the
 233    additional error message generated. */
 234 extern void gigi_abort (int) ATTRIBUTE_NORETURN;
 235
 236 /* Initialize the table that maps GNAT codes to GCC codes for simple
 237    binary and unary operations.  */
 238 extern void init_code_table (void);
 239
 240 /* Current node being treated, in case gigi_abort or Check_Elaboration_Code
 241    called.  */
 242 extern Node_Id error_gnat_node;
 243
 244 /* This is equivalent to stabilize_reference in GCC's tree.c, but we know
 245    how to handle our new nodes and we take an extra argument that says
 246    whether to force evaluation of everything.  */
 247
 248 extern tree gnat_stabilize_reference (tree, int);
 249
 250 /* Highest number in the front-end node table.  */
 251 extern int max_gnat_nodes;
 252
 253 /* If nonzero, pretend we are allocating at global level.  */
 254 extern int force_global;
 255
 256 /* Standard data type sizes.  Most of these are not used.  */
 257
 258 #ifndef CHAR_TYPE_SIZE
 259 #define CHAR_TYPE_SIZE BITS_PER_UNIT
 260 #endif
 261
 262 #ifndef SHORT_TYPE_SIZE
 263 #define SHORT_TYPE_SIZE (BITS_PER_UNIT * MIN ((UNITS_PER_WORD + 1) / 2, 2))
 264 #endif
 265
 266 #ifndef INT_TYPE_SIZE
 267 #define INT_TYPE_SIZE BITS_PER_WORD
 268 #endif
 269
 270 #ifndef LONG_TYPE_SIZE
 271 #define LONG_TYPE_SIZE BITS_PER_WORD
 272 #endif
 273
 274 #ifndef LONG_LONG_TYPE_SIZE
 275 #define LONG_LONG_TYPE_SIZE (BITS_PER_WORD * 2)
 276 #endif
 277
 278 #ifndef FLOAT_TYPE_SIZE
 279 #define FLOAT_TYPE_SIZE BITS_PER_WORD
 280 #endif
 281
 282 #ifndef DOUBLE_TYPE_SIZE
 283 #define DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
 284 #endif
 285
 286 #ifndef LONG_DOUBLE_TYPE_SIZE
 287 #define LONG_DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
 288 #endif
 289
 290 /* The choice of SIZE_TYPE here is very problematic.  We need a signed
 291    type whose bit width is Pmode.  Assume "long" is such a type here.  */
 292 #undef SIZE_TYPE
 293 #define SIZE_TYPE "long int"
 294
 295 \f
 296 /* Data structures used to represent attributes.  */
 297
 298 enum attr_type {ATTR_MACHINE_ATTRIBUTE, ATTR_LINK_ALIAS,
 299                 ATTR_LINK_SECTION, ATTR_WEAK_EXTERNAL};
 300
 301 struct attrib
 302 {
 303   struct attrib *next;
 304   enum attr_type type;
 305   tree name;
 306   tree arg;
 307   Node_Id error_point;
 308 };
 309
 310 /* Define the entries in the standard data array.  */
 311 enum standard_datatypes
 312 {
 313 /* Various standard data types and nodes.  */
 314   ADT_longest_float_type,
 315   ADT_void_type_decl,
 316
 317   /* The type of an exception.  */
 318   ADT_except_type,
 319
 320   /* Type declaration node  <==> typedef void *T */
 321   ADT_ptr_void_type,
 322
 323   /* Function type declaration -- void T() */
 324   ADT_void_ftype,
 325
 326   /* Type declaration node  <==> typedef void *T() */
 327   ADT_ptr_void_ftype,
 328
 329   /* A function declaration node for a run-time function for allocating memory.
 330      Ada allocators cause calls to this function to be generated.   */
 331   ADT_malloc_decl,
 332
 333   /* Likewise for freeing memory.  */
 334   ADT_free_decl,
 335
 336   /* Types and decls used by our temporary exception mechanism.  See
 337      init_gigi_decls for details.  */
 338   ADT_jmpbuf_type,
 339   ADT_jmpbuf_ptr_type,
 340   ADT_get_jmpbuf_decl,
 341   ADT_set_jmpbuf_decl,
 342   ADT_get_excptr_decl,
 343   ADT_setjmp_decl,
 344   ADT_longjmp_decl,
 345   ADT_update_setjmp_buf_decl,
 346   ADT_raise_nodefer_decl,
 347   ADT_begin_handler_decl,
 348   ADT_end_handler_decl,
 349   ADT_LAST};
 350
 351 extern GTY(()) tree gnat_std_decls[(int) ADT_LAST];
 352 extern GTY(()) 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 update_setjmp_buf_decl gnat_std_decls[(int) ADT_update_setjmp_buf_decl]
 370 #define raise_nodefer_decl gnat_std_decls[(int) ADT_raise_nodefer_decl]
 371 #define begin_handler_decl gnat_std_decls[(int) ADT_begin_handler_decl]
 372 #define end_handler_decl gnat_std_decls[(int) ADT_end_handler_decl]
 373
 374 /* Routines expected by the gcc back-end. They must have exactly the same
 375    prototype and names as below.  */
 376
 377 /* Returns non-zero if we are currently in the global binding level       */
 378 extern int global_bindings_p (void);
 379
 380 /* Returns the list of declarations in the current level. Note that this list
 381    is in reverse order (it has to be so for back-end compatibility).  */
 382 extern tree getdecls (void);
 383
 384 /* Nonzero if the current level needs to have a BLOCK made.  */
 385 extern int kept_level_p (void);
 386
 387 /* Enter a new binding level. The input parameter is ignored, but has to be
 388    specified for back-end compatibility.  */
 389 extern void pushlevel (int);
 390
 391 /* Exit a binding level.
 392    Pop the level off, and restore the state of the identifier-decl mappings
 393    that were in effect when this level was entered.
 394
 395    If KEEP is nonzero, this level had explicit declarations, so
 396    and create a "block" (a BLOCK node) for the level
 397    to record its declarations and subblocks for symbol table output.
 398
 399    If FUNCTIONBODY is nonzero, this level is the body of a function,
 400    so create a block as if KEEP were set and also clear out all
 401    label names.
 402
 403    If REVERSE is nonzero, reverse the order of decls before putting
 404    them into the BLOCK.  */
 405 extern tree poplevel (int, int, int);
 406
 407 /* Insert BLOCK at the end of the list of subblocks of the
 408    current binding level.  This is used when a BIND_EXPR is expanded,
 409    to handle the BLOCK node inside the BIND_EXPR.  */
 410 extern void insert_block (tree);
 411
 412 /* Set the BLOCK node for the innermost scope
 413    (the one we are currently in).  */
 414 extern void set_block (tree);
 415
 416 /* Records a ..._DECL node DECL as belonging to the current lexical scope.
 417    Returns the ..._DECL node. */
 418 extern tree pushdecl (tree);
 419
 420 /* Create the predefined scalar types such as `integer_type_node' needed
 421    in the gcc back-end and initialize the global binding level.  */
 422 extern void gnat_init_decl_processing (void);
 423 extern void init_gigi_decls (tree, tree);
 424 extern void gnat_init_gcc_eh (void);
 425
 426 /* Return an integer type with the number of bits of precision given by
 427    PRECISION.  UNSIGNEDP is nonzero if the type is unsigned; otherwise
 428    it is a signed type.  */
 429 extern tree gnat_type_for_size (unsigned, int);
 430
 431 /* Return a data type that has machine mode MODE.  UNSIGNEDP selects
 432    an unsigned type; otherwise a signed type is returned.  */
 433 extern tree gnat_type_for_mode (enum machine_mode, int);
 434
 435 /* Return the unsigned version of a TYPE_NODE, a scalar type.  */
 436 extern tree gnat_unsigned_type (tree);
 437
 438 /* Return the signed version of a TYPE_NODE, a scalar type.  */
 439 extern tree gnat_signed_type (tree);
 440
 441 /* Return a type the same as TYPE except unsigned or signed according to
 442    UNSIGNEDP.  */
 443 extern tree gnat_signed_or_unsigned_type (int, tree);
 444
 445 /* Create an expression whose value is that of EXPR,
 446    converted to type TYPE.  The TREE_TYPE of the value
 447    is always TYPE.  This function implements all reasonable
 448    conversions; callers should filter out those that are
 449    not permitted by the language being compiled.  */
 450 extern tree convert (tree, tree);
 451
 452 /* Routines created solely for the tree translator's sake. Their prototypes
 453    can be changed as desired.  */
 454
 455 /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
 456    GNU_DECL is the GCC tree which is to be associated with
 457    GNAT_ENTITY. Such gnu tree node is always an ..._DECL node.
 458    If NO_CHECK is nonzero, the latter check is suppressed.
 459    If GNU_DECL is zero, a previous association is to be reset.  */
 460 extern void save_gnu_tree (Entity_Id, tree, int);
 461
 462 /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
 463    Return the ..._DECL node that was associated with it.  If there is no tree
 464    node associated with GNAT_ENTITY, abort.  */
 465 extern tree get_gnu_tree (Entity_Id);
 466
 467 /* Return nonzero if a GCC tree has been associated with GNAT_ENTITY.  */
 468 extern int present_gnu_tree (Entity_Id);
 469
 470 /* Initialize tables for above routines.  */
 471 extern void init_gnat_to_gnu (void);
 472
 473 /* Given a record type (RECORD_TYPE) and a chain of FIELD_DECL
 474    nodes (FIELDLIST), finish constructing the record or union type.
 475    If HAS_REP is nonzero, this record has a rep clause; don't call
 476    layout_type but merely set the size and alignment ourselves.
 477    If DEFER_DEBUG is nonzero, do not call the debugging routines
 478    on this type; it will be done later. */
 479 extern void finish_record_type (tree, tree, int, int);
 480
 481 /* Returns a FUNCTION_TYPE node. RETURN_TYPE is the type returned by the
 482    subprogram. If it is void_type_node, then we are dealing with a procedure,
 483    otherwise we are dealing with a function. PARAM_DECL_LIST is a list of
 484    PARM_DECL nodes that are the subprogram arguments.  CICO_LIST is the
 485    copy-in/copy-out list to be stored into TYPE_CI_CO_LIST.
 486    RETURNS_UNCONSTRAINED is nonzero if the function returns an unconstrained
 487    object.  RETURNS_BY_REF is nonzero if the function returns by reference.
 488    RETURNS_WITH_DSP is nonzero if the function is to return with a
 489    depressed stack pointer.  */
 490 extern tree create_subprog_type (tree, tree, tree, int, int, int);
 491
 492 /* Return a copy of TYPE, but safe to modify in any way.  */
 493 extern tree copy_type (tree);
 494
 495 /* Return an INTEGER_TYPE of SIZETYPE with range MIN to MAX and whose
 496    TYPE_INDEX_TYPE is INDEX.  */
 497 extern tree create_index_type (tree, tree, tree);
 498
 499 /* Return a TYPE_DECL node. TYPE_NAME gives the name of the type (a character
 500    string) and TYPE is a ..._TYPE node giving its data type.
 501    ARTIFICIAL_P is nonzero if this is a declaration that was generated
 502    by the compiler.  DEBUG_INFO_P is nonzero if we need to write debugging
 503    information about this type.  */
 504 extern tree create_type_decl (tree, tree, struct attrib *, int, int);
 505
 506 /* Returns a GCC VAR_DECL node. VAR_NAME gives the name of the variable.
 507    ASM_NAME is its assembler name (if provided).  TYPE is
 508    its data type (a GCC ..._TYPE node).  VAR_INIT is the GCC tree for an
 509    optional initial expression; NULL_TREE if none.
 510
 511    CONST_FLAG is nonzero if this variable is constant.
 512
 513    PUBLIC_FLAG is nonzero if this definition is to be made visible outside of
 514    the current compilation unit. This flag should be set when processing the
 515    variable definitions in a package specification.  EXTERN_FLAG is nonzero
 516    when processing an external variable declaration (as opposed to a
 517    definition: no storage is to be allocated for the variable here).
 518    STATIC_FLAG is only relevant when not at top level.  In that case
 519    it indicates whether to always allocate storage to the variable.  */
 520 extern tree create_var_decl (tree, tree, tree, tree, int, int, int, int,
 521                              struct attrib *);
 522
 523 /* Given a DECL and ATTR_LIST, apply the listed attributes.  */
 524 extern void process_attributes (tree, struct attrib *);
 525
 526 /* Obtain any pending elaborations and clear the old list.  */
 527 extern tree get_pending_elaborations (void);
 528
 529 /* Return nonzero if there are pending elaborations.  */
 530 extern int pending_elaborations_p (void);
 531
 532 /* Save a copy of the current pending elaboration list and make a new
 533    one.  */
 534 extern void push_pending_elaborations (void);
 535
 536 /* Pop the stack of pending elaborations.  */
 537 extern void pop_pending_elaborations (void);
 538
 539 /* Return the current position in pending_elaborations so we can insert
 540    elaborations after that point.  */
 541 extern tree get_elaboration_location (void);
 542
 543 /* Insert the current elaborations after ELAB, which is in some elaboration
 544    list.  */
 545 extern void insert_elaboration_list (tree);
 546
 547 /* Add some pending elaborations to the current list.  */
 548 extern void add_pending_elaborations (tree, tree);
 549
 550 /* Returns a FIELD_DECL node. FIELD_NAME the field name, FIELD_TYPE is its
 551    type, and RECORD_TYPE is the type of the parent.  PACKED is nonzero if
 552    this field is in a record type with a "pragma pack".  If SIZE is nonzero
 553    it is the specified size for this field.  If POS is nonzero, it is the bit
 554    position.  If ADDRESSABLE is nonzero, it means we are allowed to take
 555    the address of this field for aliasing purposes.  */
 556 extern tree create_field_decl (tree, tree, tree, int, tree, tree, int);
 557
 558 /* Returns a PARM_DECL node. PARAM_NAME is the name of the parameter,
 559    PARAM_TYPE is its type.  READONLY is nonzero if the parameter is
 560    readonly (either an IN parameter or an address of a pass-by-ref
 561    parameter). */
 562 extern tree create_param_decl (tree, tree, int);
 563
 564 /* Returns a FUNCTION_DECL node.  SUBPROG_NAME is the name of the subprogram,
 565    ASM_NAME is its assembler name, SUBPROG_TYPE is its type (a FUNCTION_TYPE
 566    node), PARAM_DECL_LIST is the list of the subprogram arguments (a list of
 567    PARM_DECL nodes chained through the TREE_CHAIN field).
 568
 569    INLINE_FLAG, PUBLIC_FLAG, and EXTERN_FLAG are used to set the appropriate
 570    fields in the FUNCTION_DECL.  */
 571 extern tree create_subprog_decl (tree, tree, tree, tree, int, int, int,
 572                                  struct attrib *);
 573
 574 /* Returns a LABEL_DECL node for LABEL_NAME.  */
 575 extern tree create_label_decl (tree);
 576
 577 /* Set up the framework for generating code for SUBPROG_DECL, a subprogram
 578    body. This routine needs to be invoked before processing the declarations
 579    appearing in the subprogram.  */
 580 extern void begin_subprog_body (tree);
 581
 582 /* Finish the definition of the current subprogram and compile it all the way
 583    to assembler language output.  */
 584 extern void end_subprog_body (void);
 585
 586 /* Build a template of type TEMPLATE_TYPE from the array bounds of ARRAY_TYPE.
 587    EXPR is an expression that we can use to locate any PLACEHOLDER_EXPRs.
 588    Return a constructor for the template.  */
 589 extern tree build_template (tree, tree, tree);
 590
 591 /* Build a VMS descriptor from a Mechanism_Type, which must specify
 592    a descriptor type, and the GCC type of an object.  Each FIELD_DECL
 593    in the type contains in its DECL_INITIAL the expression to use when
 594    a constructor is made for the type.  GNAT_ENTITY is a gnat node used
 595    to print out an error message if the mechanism cannot be applied to
 596    an object of that type and also for the name.  */
 597
 598 extern tree build_vms_descriptor (tree, Mechanism_Type, Entity_Id);
 599
 600 /* Build a type to be used to represent an aliased object whose nominal
 601    type is an unconstrained array.  This consists of a RECORD_TYPE containing
 602    a field of TEMPLATE_TYPE and a field of OBJECT_TYPE, which is an
 603    ARRAY_TYPE.  If ARRAY_TYPE is that of the unconstrained array, this
 604    is used to represent an arbitrary unconstrained object.  Use NAME
 605    as the name of the record.  */
 606 extern tree build_unc_object_type (tree, tree, tree);
 607
 608 /* Update anything previously pointing to OLD_TYPE to point to NEW_TYPE.  In
 609    the normal case this is just two adjustments, but we have more to do
 610    if NEW is an UNCONSTRAINED_ARRAY_TYPE.  */
 611 extern void update_pointer_to (tree, tree);
 612
 613 /* EXP is an expression for the size of an object.  If this size contains
 614    discriminant references, replace them with the maximum (if MAX_P) or
 615    minimum (if ! MAX_P) possible value of the discriminant.  */
 616 extern tree max_size (tree, int);
 617
 618 /* Remove all conversions that are done in EXP.  This includes converting
 619    from a padded type or to a left-justified modular type.  If TRUE_ADDRESS
 620    is nonzero, always return the address of the containing object even if
 621    the address is not bit-aligned.  */
 622 extern tree remove_conversions (tree, int);
 623
 624 /* If EXP's type is an UNCONSTRAINED_ARRAY_TYPE, return an expression that
 625    refers to the underlying array.  If its type has TYPE_CONTAINS_TEMPLATE_P,
 626    likewise return an expression pointing to the underlying array.  */
 627 extern tree maybe_unconstrained_array (tree);
 628
 629 /* Return an expression that does an unchecked converstion of EXPR to TYPE.
 630    If NOTRUNC_P is set, truncation operations should be suppressed.  */
 631 extern tree unchecked_convert (tree, tree, int);
 632
 633 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR or other logical
 634    operation.
 635
 636    This preparation consists of taking the ordinary
 637    representation of an expression expr and producing a valid tree
 638    boolean expression describing whether expr is nonzero.  We could
 639    simply always do build_binary_op (NE_EXPR, expr, integer_zero_node, 1),
 640    but we optimize comparisons, &&, ||, and !.
 641
 642    The resulting type should always be the same as the input type.
 643    This function is simpler than the corresponding C version since
 644    the only possible operands will be things of Boolean type.  */
 645 extern tree gnat_truthvalue_conversion (tree);
 646
 647 /* Return the base type of TYPE.  */
 648 extern tree get_base_type (tree);
 649
 650 /* Likewise, but only return types known at Ada source.  */
 651 extern tree get_ada_base_type (tree);
 652
 653 /* EXP is a GCC tree representing an address.  See if we can find how
 654    strictly the object at that address is aligned.   Return that alignment
 655    strictly the object at that address is aligned.   Return that alignment
 656    in bits.  If we don't know anything about the alignment, return 0.  */
 657 extern unsigned int known_alignment (tree);
 658
 659 /* Make a binary operation of kind OP_CODE.  RESULT_TYPE is the type
 660    desired for the result.  Usually the operation is to be performed
 661    in that type.  For MODIFY_EXPR and ARRAY_REF, RESULT_TYPE may be 0
 662    in which case the type to be used will be derived from the operands.  */
 663 extern tree build_binary_op (enum tree_code, tree, tree, tree);
 664
 665 /* Similar, but make unary operation.   */
 666 extern tree build_unary_op (enum tree_code, tree, tree);
 667
 668 /* Similar, but for COND_EXPR.  */
 669 extern tree build_cond_expr (tree, tree, tree, tree);
 670
 671 /* Build a CALL_EXPR to call FUNDECL with one argument, ARG.  Return
 672    the CALL_EXPR.  */
 673 extern tree build_call_1_expr (tree, tree);
 674
 675 /* Build a CALL_EXPR to call FUNDECL with two argument, ARG1 & ARG2.  Return
 676    the CALL_EXPR.  */
 677 extern tree build_call_2_expr (tree, tree, tree);
 678
 679 /* Likewise to call FUNDECL with no arguments.  */
 680 extern tree build_call_0_expr (tree);
 681
 682 /* Call a function that raises an exception and pass the line number and file
 683    name, if requested.  MSG says which exception function to call.  */
 684 extern tree build_call_raise (int);
 685
 686 /* Return a CONSTRUCTOR of TYPE whose list is LIST.  This is not the
 687    same as build_constructor in the language-independent tree.c.  */
 688 extern tree gnat_build_constructor (tree, tree);
 689
 690 /* Return a COMPONENT_REF to access a field that is given by COMPONENT,
 691    an IDENTIFIER_NODE giving the name of the field, FIELD, a FIELD_DECL,
 692    for the field, or both.  Don't fold the result if NO_FOLD_P.  */
 693 extern tree build_component_ref (tree, tree, tree, int);
 694
 695 /* Build a GCC tree to call an allocation or deallocation function.
 696    If GNU_OBJ is nonzero, it is an object to deallocate.  Otherwise,
 697    genrate an allocator.
 698
 699    GNU_SIZE is the size of the object and ALIGN is the alignment.
 700    GNAT_PROC, if present is a procedure to call and GNAT_POOL is the
 701    storage pool to use.  If not preset, malloc and free will be used.  */
 702 extern tree build_call_alloc_dealloc (tree, tree, unsigned int, Entity_Id,
 703                                       Entity_Id, Node_Id);
 704
 705 /* Build a GCC tree to correspond to allocating an object of TYPE whose
 706    initial value if INIT, if INIT is nonzero.  Convert the expression to
 707    RESULT_TYPE, which must be some type of pointer.  Return the tree.
 708    GNAT_PROC and GNAT_POOL optionally give the procedure to call and
 709    the storage pool to use.  GNAT_NODE is used to provide an error
 710    location for restriction violations messages.  */
 711 extern tree build_allocator (tree, tree, tree, Entity_Id, Entity_Id, Node_Id);
 712
 713 /* Fill in a VMS descriptor for EXPR and return a constructor for it.
 714    GNAT_FORMAL is how we find the descriptor record.  */
 715
 716 extern tree fill_vms_descriptor (tree, Entity_Id);
 717
 718 /* Indicate that we need to make the address of EXPR_NODE and it therefore
 719    should not be allocated in a register.  Return true if successful.  */
 720 extern bool gnat_mark_addressable (tree);
 721
 722 /* This function is called by the front end to enumerate all the supported
 723    modes for the machine.  We pass a function which is called back with
 724    the following integer parameters:
 725
 726    FLOAT_P      nonzero if this represents a floating-point mode
 727    COMPLEX_P    nonzero is this represents a complex mode
 728    COUNT        count of number of items, nonzero for vector mode
 729    PRECISION    number of bits in data representation
 730    MANTISSA     number of bits in mantissa, if FP and known, else zero.
 731    SIZE         number of bits used to store data
 732    ALIGN        number of bits to which mode is aligned.  */
 733 extern void enumerate_modes (void (*f) (int, int, int, int, int, int,
 734                                         unsigned int));
 735
 736 /* These are temporary function to deal with recent GCC changes related to
 737    FP type sizes and precisions.  */
 738 extern int fp_prec_to_size (int);
 739 extern int fp_size_to_prec (int);
 740
 741 /* These functions return the basic data type sizes and related parameters
 742    about the target machine.  */
 743
 744 extern Pos get_target_bits_per_unit (void);
 745 extern Pos get_target_bits_per_word (void);
 746 extern Pos get_target_char_size (void);
 747 extern Pos get_target_wchar_t_size (void);
 748 extern Pos get_target_short_size (void);
 749 extern Pos get_target_int_size (void);
 750 extern Pos get_target_long_size (void);
 751 extern Pos get_target_long_long_size (void);
 752 extern Pos get_target_float_size (void);
 753 extern Pos get_target_double_size (void);
 754 extern Pos get_target_long_double_size (void);
 755 extern Pos get_target_pointer_size (void);
 756 extern Pos get_target_maximum_alignment (void);
 757 extern Nat get_float_words_be (void);
 758 extern Nat get_words_be (void);
 759 extern Nat get_bytes_be (void);
 760 extern Nat get_bits_be (void);
 761 extern Nat get_strict_alignment (void);