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