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) 1992-2005 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 /* Declare all functions and types used by gigi.  */
  34
  35 /* The largest alignment, in bits, that is needed for using the widest
  36    move instruction.  */
  37 extern unsigned int largest_move_alignment;
  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 /* GNU_TYPE is a type. Determine if it should be passed by reference by
  44    default.  */
  45 extern bool default_pass_by_ref (tree gnu_type);
  46
  47 /* GNU_TYPE is the type of a subprogram parameter.  Determine from the type
  48    if it should be passed by reference.  */
  49 extern bool must_pass_by_ref (tree gnu_type);
  50
  51 /* Initialize DUMMY_NODE_TABLE.  */
  52 extern void init_dummy_type (void);
  53
  54 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
  55    entity, this routine returns the equivalent GCC tree for that entity
  56    (an ..._DECL node) and associates the ..._DECL node with the input GNAT
  57    defining identifier.
  58
  59    If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
  60    initial value (in GCC tree form). This is optional for variables.
  61    For renamed entities, GNU_EXPR gives the object being renamed.
  62
  63    DEFINITION is nonzero if this call is intended for a definition.  This is
  64    used for separate compilation where it necessary to know whether an
  65    external declaration or a definition should be created if the GCC equivalent
  66    was not created previously.  The value of 1 is normally used for a non-zero
  67    DEFINITION, but a value of 2 is used in special circumstances, defined in
  68    the code.  */
  69 extern tree gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr,
  70                                 int definition);
  71
  72 /* Similar, but if the returned value is a COMPONENT_REF, return the
  73    FIELD_DECL.  */
  74 extern tree gnat_to_gnu_field_decl (Entity_Id gnat_entity);
  75
  76 /* Given GNAT_ENTITY, an entity in the incoming GNAT tree, return a
  77    GCC type corresponding to that entity.  GNAT_ENTITY is assumed to
  78    refer to an Ada type.  */
  79 extern tree gnat_to_gnu_type (Entity_Id gnat_entity);
  80
  81 /* Add GNU_STMT to the current BLOCK_STMT node.  */
  82 extern void add_stmt (tree gnu_stmt);
  83
  84 /* Similar, but set the location of GNU_STMT to that of GNAT_NODE.  */
  85 extern void add_stmt_with_node (tree gnu_stmt, Node_Id gnat_node);
  86
  87 /* Set the BLOCK node corresponding to the current code group to GNU_BLOCK.  */
  88 extern void set_block_for_group (tree);
  89
  90 /* Add a declaration statement for GNU_DECL to the current BLOCK_STMT node.
  91    Get SLOC from GNAT_ENTITY.  */
  92 extern void add_decl_expr (tree gnu_decl, Entity_Id gnat_entity);
  93
  94 /* Given GNAT_ENTITY, elaborate all expressions that are required to
  95    be elaborated at the point of its definition, but do nothing else.  */
  96 extern void elaborate_entity (Entity_Id gnat_entity);
  97
  98 /* Mark GNAT_ENTITY as going out of scope at this point.  Recursively mark
  99    any entities on its entity chain similarly.  */
 100 extern void mark_out_of_scope (Entity_Id gnat_entity);
 101
 102 /* Make a dummy type corresponding to GNAT_TYPE.  */
 103 extern tree make_dummy_type (Entity_Id gnat_type);
 104
 105 /* Get the unpadded version of a GNAT type.  */
 106 extern tree get_unpadded_type (Entity_Id gnat_entity);
 107
 108 /* Called when we need to protect a variable object using a save_expr.  */
 109 extern tree maybe_variable (tree gnu_operand);
 110
 111 /* Create a record type that contains a field of TYPE with a starting bit
 112    position so that it is aligned to ALIGN bits and is SIZE bytes long.  */
 113 extern tree make_aligning_type (tree type, int align, tree size);
 114
 115 /* Ensure that TYPE has SIZE and ALIGN.  Make and return a new padded type
 116    if needed.  We have already verified that SIZE and TYPE are large enough.
 117
 118    GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
 119    to issue a warning.
 120
 121    IS_USER_TYPE is true if we must be sure we complete the original type.
 122
 123    DEFINITION is true if this type is being defined.
 124
 125    SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
 126    set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
 127    type.  */
 128 extern tree maybe_pad_type (tree type, tree size, unsigned int align,
 129                             Entity_Id gnat_entity, const char *name_trailer,
 130                             bool is_user_type, bool definition,
 131                             bool same_rm_size);
 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 operand, Node_Id choices);
 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 t, tree f, tree r);
 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 gnu_type);
 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 gnu_id, const char *suffix);
 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 gnat_entity);
 156
 157 /* Return a name for GNAT_ENTITY concatenated with two underscores and
 158    SUFFIX.  */
 159 extern tree create_concat_name (Entity_Id gnat_entity, const char *suffix);
 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    ??? Needs parameter descriptions  */
 173
 174 extern void gigi (Node_Id gnat_root, int max_gnat_node, int number_name,
 175                   struct Node *nodes_ptr, Node_Id *next_node_ptr,
 176                   Node_Id *prev_node_ptr, struct Elist_Header *elists_ptr,
 177                   struct Elmt_Item *elmts_ptr,
 178                   struct String_Entry *strings_ptr,
 179                   Char_Code *strings_chars_ptr,
 180                   struct List_Header *list_headers_ptr,
 181                   Int number_units ATTRIBUTE_UNUSED,
 182                   char *file_info_ptr ATTRIBUTE_UNUSED,
 183                   Entity_Id standard_integer,
 184                   Entity_Id standard_long_long_float,
 185                   Entity_Id standard_exception_type,
 186                   Int gigi_operating_mode);
 187
 188 /* GNAT_NODE is the root of some GNAT tree.  Return the root of the
 189    GCC tree corresponding to that GNAT tree.  Normally, no code is generated;
 190    we just return an equivalent tree which is used elsewhere to generate
 191    code.  */
 192 extern tree gnat_to_gnu (Node_Id gnat_node);
 193
 194 /* GNU_STMT is a statement.  We generate code for that statement.  */
 195 extern void gnat_expand_stmt (tree gnu_stmt);
 196
 197 /* ??? missing documentation */
 198 extern int gnat_gimplify_expr (tree *expr_p, tree *pre_p,
 199                                tree *post_p ATTRIBUTE_UNUSED);
 200
 201 /* Do the processing for the declaration of a GNAT_ENTITY, a type.  If
 202    a separate Freeze node exists, delay the bulk of the processing.  Otherwise
 203    make a GCC type for GNAT_ENTITY and set up the correspondence.  */
 204 extern void process_type (Entity_Id gnat_entity);
 205
 206 /* Convert Sloc into *LOCUS (a location_t).  Return true if this Sloc
 207    corresponds to a source code location and false if it doesn't.  In the
 208    latter case, we don't update *LOCUS.  We also set the Gigi global variable
 209    REF_FILENAME to the reference file name as given by sinput (i.e no
 210    directory).  */
 211 extern bool Sloc_to_locus (Source_Ptr Sloc, location_t *locus);
 212
 213 /* Post an error message.  MSG is the error message, properly annotated.
 214    NODE is the node at which to post the error and the node to use for the
 215    "&" substitution.  */
 216 extern void post_error (const char *, Node_Id);
 217
 218 /* Similar, but NODE is the node at which to post the error and ENT
 219    is the node to use for the "&" substitution.  */
 220 extern void post_error_ne (const char *msg, Node_Id node, Entity_Id ent);
 221
 222 /* Similar, but NODE is the node at which to post the error, ENT is the node
 223    to use for the "&" substitution, and N is the number to use for the ^.  */
 224 extern void post_error_ne_num (const char *msg, Node_Id node, Entity_Id ent,
 225                                int n);
 226
 227 /* Similar to post_error_ne_num, but T is a GCC tree representing the number
 228    to write.  If the tree represents a constant that fits within a
 229    host integer, the text inside curly brackets in MSG will be output
 230    (presumably including a '^').  Otherwise that text will not be output
 231    and the text inside square brackets will be output instead.  */
 232 extern void post_error_ne_tree (const char *msg, Node_Id node, Entity_Id ent,
 233                                 tree t);
 234
 235 /* Similar to post_error_ne_tree, except that NUM is a second
 236    integer to write in the message.  */
 237 extern void post_error_ne_tree_2 (const char *msg, Node_Id node, Entity_Id ent,
 238                                   tree t, int num);
 239
 240 /* Protect EXP from multiple evaluation.  This may make a SAVE_EXPR.  */
 241 extern tree protect_multiple_eval (tree exp);
 242
 243 /* Initialize the table that maps GNAT codes to GCC codes for simple
 244    binary and unary operations.  */
 245 extern void init_code_table (void);
 246
 247 /* Current node being treated, in case gigi_abort or Check_Elaboration_Code
 248    called.  */
 249 extern Node_Id error_gnat_node;
 250
 251 /* This is equivalent to stabilize_reference in GCC's tree.c, but we know
 252    how to handle our new nodes and we take an extra argument that says
 253    whether to force evaluation of everything.  */
 254 extern tree gnat_stabilize_reference (tree ref, bool force);
 255
 256 /* Highest number in the front-end node table.  */
 257 extern int max_gnat_nodes;
 258
 259 /* If nonzero, pretend we are allocating at global level.  */
 260 extern int force_global;
 261
 262 /* Standard data type sizes.  Most of these are not used.  */
 263
 264 #ifndef CHAR_TYPE_SIZE
 265 #define CHAR_TYPE_SIZE BITS_PER_UNIT
 266 #endif
 267
 268 #ifndef SHORT_TYPE_SIZE
 269 #define SHORT_TYPE_SIZE (BITS_PER_UNIT * MIN ((UNITS_PER_WORD + 1) / 2, 2))
 270 #endif
 271
 272 #ifndef INT_TYPE_SIZE
 273 #define INT_TYPE_SIZE BITS_PER_WORD
 274 #endif
 275
 276 #ifndef LONG_TYPE_SIZE
 277 #define LONG_TYPE_SIZE BITS_PER_WORD
 278 #endif
 279
 280 #ifndef LONG_LONG_TYPE_SIZE
 281 #define LONG_LONG_TYPE_SIZE (BITS_PER_WORD * 2)
 282 #endif
 283
 284 #ifndef FLOAT_TYPE_SIZE
 285 #define FLOAT_TYPE_SIZE BITS_PER_WORD
 286 #endif
 287
 288 #ifndef DOUBLE_TYPE_SIZE
 289 #define DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
 290 #endif
 291
 292 #ifndef LONG_DOUBLE_TYPE_SIZE
 293 #define LONG_DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
 294 #endif
 295
 296 /* The choice of SIZE_TYPE here is very problematic.  We need a signed
 297    type whose bit width is Pmode.  Assume "long" is such a type here.  */
 298 #undef SIZE_TYPE
 299 #define SIZE_TYPE "long int"
 300
 301 \f
 302 /* Data structures used to represent attributes.  */
 303
 304 enum attr_type {ATTR_MACHINE_ATTRIBUTE, ATTR_LINK_ALIAS,
 305                 ATTR_LINK_SECTION, ATTR_WEAK_EXTERNAL};
 306
 307 struct attrib
 308 {
 309   struct attrib *next;
 310   enum attr_type type;
 311   tree name;
 312   tree args;
 313   Node_Id error_point;
 314 };
 315
 316 /* Define the entries in the standard data array.  */
 317 enum standard_datatypes
 318 {
 319 /* Various standard data types and nodes.  */
 320   ADT_longest_float_type,
 321   ADT_void_type_decl,
 322
 323   /* The type of an exception.  */
 324   ADT_except_type,
 325
 326   /* Type declaration node  <==> typedef void *T */
 327   ADT_ptr_void_type,
 328
 329   /* Function type declaration -- void T() */
 330   ADT_void_ftype,
 331
 332   /* Type declaration node  <==> typedef void *T() */
 333   ADT_ptr_void_ftype,
 334
 335   /* A function declaration node for a run-time function for allocating memory.
 336      Ada allocators cause calls to this function to be generated.   */
 337   ADT_malloc_decl,
 338
 339   /* Likewise for freeing memory.  */
 340   ADT_free_decl,
 341
 342   /* Types and decls used by our temporary exception mechanism.  See
 343      init_gigi_decls for details.  */
 344   ADT_jmpbuf_type,
 345   ADT_jmpbuf_ptr_type,
 346   ADT_get_jmpbuf_decl,
 347   ADT_set_jmpbuf_decl,
 348   ADT_get_excptr_decl,
 349   ADT_setjmp_decl,
 350   ADT_longjmp_decl,
 351   ADT_update_setjmp_buf_decl,
 352   ADT_raise_nodefer_decl,
 353   ADT_begin_handler_decl,
 354   ADT_end_handler_decl,
 355   ADT_others_decl,
 356   ADT_all_others_decl,
 357   ADT_LAST};
 358
 359 extern GTY(()) tree gnat_std_decls[(int) ADT_LAST];
 360 extern GTY(()) tree gnat_raise_decls[(int) LAST_REASON_CODE + 1];
 361
 362 #define longest_float_type_node gnat_std_decls[(int) ADT_longest_float_type]
 363 #define void_type_decl_node gnat_std_decls[(int) ADT_void_type_decl]
 364 #define except_type_node gnat_std_decls[(int) ADT_except_type]
 365 #define ptr_void_type_node gnat_std_decls[(int) ADT_ptr_void_type]
 366 #define void_ftype gnat_std_decls[(int) ADT_void_ftype]
 367 #define ptr_void_ftype gnat_std_decls[(int) ADT_ptr_void_ftype]
 368 #define malloc_decl gnat_std_decls[(int) ADT_malloc_decl]
 369 #define free_decl gnat_std_decls[(int) ADT_free_decl]
 370 #define jmpbuf_type gnat_std_decls[(int) ADT_jmpbuf_type]
 371 #define jmpbuf_ptr_type gnat_std_decls[(int) ADT_jmpbuf_ptr_type]
 372 #define get_jmpbuf_decl gnat_std_decls[(int) ADT_get_jmpbuf_decl]
 373 #define set_jmpbuf_decl gnat_std_decls[(int) ADT_set_jmpbuf_decl]
 374 #define get_excptr_decl gnat_std_decls[(int) ADT_get_excptr_decl]
 375 #define setjmp_decl gnat_std_decls[(int) ADT_setjmp_decl]
 376 #define longjmp_decl gnat_std_decls[(int) ADT_longjmp_decl]
 377 #define update_setjmp_buf_decl gnat_std_decls[(int) ADT_update_setjmp_buf_decl]
 378 #define raise_nodefer_decl gnat_std_decls[(int) ADT_raise_nodefer_decl]
 379 #define begin_handler_decl gnat_std_decls[(int) ADT_begin_handler_decl]
 380 #define others_decl gnat_std_decls[(int) ADT_others_decl]
 381 #define all_others_decl gnat_std_decls[(int) ADT_all_others_decl]
 382 #define end_handler_decl gnat_std_decls[(int) ADT_end_handler_decl]
 383
 384 /* Routines expected by the gcc back-end. They must have exactly the same
 385    prototype and names as below.  */
 386
 387 /* Returns non-zero if we are currently in the global binding level       */
 388 extern int global_bindings_p (void);
 389
 390 /* Enter and exit a new binding level. */
 391 extern void gnat_pushlevel (void);
 392 extern void gnat_poplevel (void);
 393
 394 /* Set SUPERCONTEXT of the BLOCK for the current binding level to FNDECL
 395    and point FNDECL to this BLOCK.  */
 396 extern void set_current_block_context (tree fndecl);
 397
 398 /* Set the jmpbuf_decl for the current binding level to DECL.  */
 399 extern void set_block_jmpbuf_decl (tree decl);
 400
 401 /* Get the setjmp_decl, if any, for the current binding level.  */
 402 extern tree get_block_jmpbuf_decl (void);
 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 (tree block);
 408
 409 /* Records a ..._DECL node DECL as belonging to the current lexical scope
 410    and uses GNAT_NODE for location information.  */
 411 extern void gnat_pushdecl (tree decl, Node_Id gnat_node);
 412
 413 extern void gnat_init_stmt_group (void);
 414 extern void gnat_init_decl_processing (void);
 415 extern void init_gigi_decls (tree long_long_float_type, tree exception_type);
 416 extern void gnat_init_gcc_eh (void);
 417
 418 /* Return an integer type with the number of bits of precision given by
 419    PRECISION.  UNSIGNEDP is nonzero if the type is unsigned; otherwise
 420    it is a signed type.  */
 421 extern tree gnat_type_for_size (unsigned precision, int unsignedp);
 422
 423 /* Return a data type that has machine mode MODE.  UNSIGNEDP selects
 424    an unsigned type; otherwise a signed type is returned.  */
 425 extern tree gnat_type_for_mode (enum machine_mode mode, int unsignedp);
 426
 427 /* Return the unsigned version of a TYPE_NODE, a scalar type.  */
 428 extern tree gnat_unsigned_type (tree type_node);
 429
 430 /* Return the signed version of a TYPE_NODE, a scalar type.  */
 431 extern tree gnat_signed_type (tree type_node);
 432
 433 /* Return a type the same as TYPE except unsigned or signed according to
 434    UNSIGNEDP.  */
 435 extern tree gnat_signed_or_unsigned_type (int unsignedp, tree type);
 436
 437 /* Create an expression whose value is that of EXPR,
 438    converted to type TYPE.  The TREE_TYPE of the value
 439    is always TYPE.  This function implements all reasonable
 440    conversions; callers should filter out those that are
 441    not permitted by the language being compiled.  */
 442 extern tree convert (tree type, tree expr);
 443
 444 /* Routines created solely for the tree translator's sake. Their prototypes
 445    can be changed as desired.  */
 446
 447 /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
 448    GNU_DECL is the GCC tree which is to be associated with
 449    GNAT_ENTITY. Such gnu tree node is always an ..._DECL node.
 450    If NO_CHECK is nonzero, the latter check is suppressed.
 451    If GNU_DECL is zero, a previous association is to be reset.  */
 452 extern void save_gnu_tree (Entity_Id gnat_entity, tree gnu_decl,
 453                            bool no_check);
 454
 455 /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
 456    Return the ..._DECL node that was associated with it.  If there is no tree
 457    node associated with GNAT_ENTITY, abort.  */
 458 extern tree get_gnu_tree (Entity_Id gnat_entity);
 459
 460 /* Return nonzero if a GCC tree has been associated with GNAT_ENTITY.  */
 461 extern bool present_gnu_tree (Entity_Id gnat_entity);
 462
 463 /* Initialize tables for above routines.  */
 464 extern void init_gnat_to_gnu (void);
 465
 466 /* Given a record type (RECORD_TYPE) and a chain of FIELD_DECL
 467    nodes (FIELDLIST), finish constructing the record or union type.
 468    If HAS_REP is true, this record has a rep clause; don't call
 469    layout_type but merely set the size and alignment ourselves.
 470    If DEFER_DEBUG is true, do not call the debugging routines
 471    on this type; it will be done later. */
 472 extern void finish_record_type (tree record_type, tree fieldlist,
 473                                 bool has_rep, bool defer_debug);
 474
 475 /*  Output the debug information associated to a record type.  */
 476 extern void write_record_type_debug_info (tree);
 477
 478 /* Returns a FUNCTION_TYPE node. RETURN_TYPE is the type returned by the
 479    subprogram. If it is void_type_node, then we are dealing with a procedure,
 480    otherwise we are dealing with a function. PARAM_DECL_LIST is a list of
 481    PARM_DECL nodes that are the subprogram arguments.  CICO_LIST is the
 482    copy-in/copy-out list to be stored into TYPE_CI_CO_LIST.
 483    RETURNS_UNCONSTRAINED is true if the function returns an unconstrained
 484    object.  RETURNS_BY_REF is true if the function returns by reference.
 485    RETURNS_WITH_DSP is true if the function is to return with a
 486    depressed stack pointer.  RETURNS_BY_TARGET_PTR is true if the function
 487    is to be passed (as its first parameter) the address of the place to copy
 488    its result.  */
 489 extern tree create_subprog_type (tree return_type, tree param_decl_list,
 490                                  tree cico_list, bool returns_unconstrained,
 491                                  bool returns_by_ref, bool returns_with_dsp,
 492                                  bool returns_by_target_ptr);
 493
 494 /* Return a copy of TYPE, but safe to modify in any way.  */
 495 extern tree copy_type (tree type);
 496
 497 /* Return an INTEGER_TYPE of SIZETYPE with range MIN to MAX and whose
 498    TYPE_INDEX_TYPE is INDEX.  */
 499 extern tree create_index_type (tree min, tree max, tree index);
 500
 501 /* Return a TYPE_DECL node. TYPE_NAME gives the name of the type (a character
 502    string) and TYPE is a ..._TYPE node giving its data type.
 503    ARTIFICIAL_P is true if this is a declaration that was generated
 504    by the compiler.  DEBUG_INFO_P is true if we need to write debugging
 505    information about this type.  GNAT_NODE is used for the position of
 506    the decl.  */
 507 extern tree create_type_decl (tree type_name, tree type,
 508                               struct attrib *attr_list,
 509                               bool artificial_p, bool debug_info_p,
 510                               Node_Id gnat_node);
 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 true if this variable is constant.
 518
 519    PUBLIC_FLAG is true 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
 525    STATIC_FLAG is only relevant when not at top level.  In that case
 526    it indicates whether to always allocate storage to the variable.
 527
 528    GNAT_NODE is used for the position of the decl.  */
 529 extern tree create_var_decl (tree var_name, tree asm_name, tree type,
 530                              tree var_init, bool const_flag,
 531                              bool public_flag, bool extern_flag,
 532                              bool static_flag,
 533                              struct attrib *attr_list, Node_Id gnat_node);
 534
 535 /* Given a DECL and ATTR_LIST, apply the listed attributes.  */
 536 extern void process_attributes (tree decl, struct attrib *attr_list);
 537
 538 /* Returns a FIELD_DECL node. FIELD_NAME the field name, FIELD_TYPE is its
 539    type, and RECORD_TYPE is the type of the parent.  PACKED is nonzero if
 540    this field is in a record type with a "pragma pack".  If SIZE is nonzero
 541    it is the specified size for this field.  If POS is nonzero, it is the bit
 542    position.  If ADDRESSABLE is nonzero, it means we are allowed to take
 543    the address of this field for aliasing purposes.  */
 544 extern tree create_field_decl (tree field_name, tree field_type,
 545                                tree record_type, int packed, tree size,
 546                                tree pos, int addressable);
 547
 548 /* Returns a PARM_DECL node. PARAM_NAME is the name of the parameter,
 549    PARAM_TYPE is its type.  READONLY is true if the parameter is
 550    readonly (either an IN parameter or an address of a pass-by-ref
 551    parameter). */
 552 extern tree create_param_decl (tree param_name, tree param_type,
 553                                bool readonly);
 554
 555 /* Returns a FUNCTION_DECL node.  SUBPROG_NAME is the name of the subprogram,
 556    ASM_NAME is its assembler name, SUBPROG_TYPE is its type (a FUNCTION_TYPE
 557    node), PARAM_DECL_LIST is the list of the subprogram arguments (a list of
 558    PARM_DECL nodes chained through the TREE_CHAIN field).
 559
 560    INLINE_FLAG, PUBLIC_FLAG, EXTERN_FLAG, and ATTR_LIST are used to set the
 561    appropriate fields in the FUNCTION_DECL.  GNAT_NODE gives the location.  */
 562 extern tree create_subprog_decl (tree subprog_name, tree asm_name,
 563                                  tree subprog_type, tree param_decl_list,
 564                                  bool inlinee_flag, bool public_flag,
 565                                  bool extern_flag,
 566                                  struct attrib *attr_list, Node_Id gnat_node);
 567
 568 /* Returns a LABEL_DECL node for LABEL_NAME.  */
 569 extern tree create_label_decl (tree label_name);
 570
 571 /* Set up the framework for generating code for SUBPROG_DECL, a subprogram
 572    body. This routine needs to be invoked before processing the declarations
 573    appearing in the subprogram.  */
 574 extern void begin_subprog_body (tree subprog_decl);
 575
 576 /* Finish the definition of the current subprogram and compile it all the way
 577    to assembler language output.  BODY is the tree corresponding to
 578    the subprogram.  */
 579 extern void end_subprog_body (tree body);
 580
 581 /* Build a template of type TEMPLATE_TYPE from the array bounds of ARRAY_TYPE.
 582    EXPR is an expression that we can use to locate any PLACEHOLDER_EXPRs.
 583    Return a constructor for the template.  */
 584 extern tree build_template (tree template_type, tree array_type, tree expr);
 585
 586 /* Build a VMS descriptor from a Mechanism_Type, which must specify
 587    a descriptor type, and the GCC type of an object.  Each FIELD_DECL
 588    in the type contains in its DECL_INITIAL the expression to use when
 589    a constructor is made for the type.  GNAT_ENTITY is a gnat node used
 590    to print out an error message if the mechanism cannot be applied to
 591    an object of that type and also for the name.  */
 592
 593 extern tree build_vms_descriptor (tree type, Mechanism_Type mech,
 594                                   Entity_Id gnat_entity);
 595
 596 /* Build a type to be used to represent an aliased object whose nominal
 597    type is an unconstrained array.  This consists of a RECORD_TYPE containing
 598    a field of TEMPLATE_TYPE and a field of OBJECT_TYPE, which is an
 599    ARRAY_TYPE.  If ARRAY_TYPE is that of the unconstrained array, this
 600    is used to represent an arbitrary unconstrained object.  Use NAME
 601    as the name of the record.  */
 602 extern tree build_unc_object_type (tree template_type, tree object_type,
 603                                    tree name);
 604
 605 /* Update anything previously pointing to OLD_TYPE to point to NEW_TYPE.  In
 606    the normal case this is just two adjustments, but we have more to do
 607    if NEW is an UNCONSTRAINED_ARRAY_TYPE.  */
 608 extern void update_pointer_to (tree old_type, tree new_type);
 609
 610 /* EXP is an expression for the size of an object.  If this size contains
 611    discriminant references, replace them with the maximum (if MAX_P) or
 612    minimum (if !MAX_P) possible value of the discriminant.  */
 613 extern tree max_size (tree exp, bool max_p);
 614
 615 /* Remove all conversions that are done in EXP.  This includes converting
 616    from a padded type or to a left-justified modular type.  If TRUE_ADDRESS
 617    is true, always return the address of the containing object even if
 618    the address is not bit-aligned.  */
 619 extern tree remove_conversions (tree exp, bool true_address);
 620
 621 /* If EXP's type is an UNCONSTRAINED_ARRAY_TYPE, return an expression that
 622    refers to the underlying array.  If its type has TYPE_CONTAINS_TEMPLATE_P,
 623    likewise return an expression pointing to the underlying array.  */
 624 extern tree maybe_unconstrained_array (tree exp);
 625
 626 /* Return an expression that does an unchecked conversion of EXPR to TYPE.
 627    If NOTRUNC_P is true, truncation operations should be suppressed.  */
 628 extern tree unchecked_convert (tree type, tree expr, bool notrunc_p);
 629
 630 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR or other logical
 631    operation.
 632
 633    This preparation consists of taking the ordinary
 634    representation of an expression EXPR and producing a valid tree
 635    boolean expression describing whether EXPR is nonzero.  We could
 636    simply always do build_binary_op (NE_EXPR, expr, integer_zero_node, 1),
 637    but we optimize comparisons, &&, ||, and !.
 638
 639    The resulting type should always be the same as the input type.
 640    This function is simpler than the corresponding C version since
 641    the only possible operands will be things of Boolean type.  */
 642 extern tree gnat_truthvalue_conversion (tree expr);
 643
 644 /* Return the base type of TYPE.  */
 645 extern tree get_base_type (tree type);
 646
 647 /* Likewise, but only return types known at Ada source.  */
 648 extern tree get_ada_base_type (tree type);
 649
 650 /* EXP is a GCC tree representing an address.  See if we can find how
 651    strictly the object at that address is aligned.   Return that alignment
 652    strictly the object at that address is aligned.   Return that alignment
 653    in bits.  If we don't know anything about the alignment, return 0.  */
 654 extern unsigned int known_alignment (tree exp);
 655
 656 /* Make a binary operation of kind OP_CODE.  RESULT_TYPE is the type
 657    desired for the result.  Usually the operation is to be performed
 658    in that type.  For MODIFY_EXPR and ARRAY_REF, RESULT_TYPE may be 0
 659    in which case the type to be used will be derived from the operands.  */
 660 extern tree build_binary_op (enum tree_code op_code, tree retult_type,
 661                              tree left_operand, tree right_operand);
 662
 663 /* Similar, but make unary operation.   */
 664 extern tree build_unary_op (enum tree_code op_code, tree result_type,
 665                             tree operand);
 666
 667 /* Similar, but for COND_EXPR.  */
 668 extern tree build_cond_expr (tree result_type, tree condition_operand,
 669                              tree true_operand, tree false_operand);
 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 fundecl, tree arg);
 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 fundecl, tree arg1, tree arg2);
 678
 679 /* Likewise to call FUNDECL with no arguments.  */
 680 extern tree build_call_0_expr (tree fundecl);
 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 msg);
 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 type, tree list);
 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 record_variable, tree component,
 694                                  tree field, bool no_fold_p);
 695
 696 /* Build a GCC tree to call an allocation or deallocation function.
 697    If GNU_OBJ is nonzero, it is an object to deallocate.  Otherwise,
 698    genrate an allocator.
 699
 700    GNU_SIZE is the size of the object and ALIGN is the alignment.
 701    GNAT_PROC, if present is a procedure to call and GNAT_POOL is the
 702    storage pool to use.  If not preset, malloc and free will be used.  */
 703 extern tree build_call_alloc_dealloc (tree gnu_obj, tree gnu_size,
 704                                       unsigned align, Entity_Id gnat_proc,
 705                                       Entity_Id gnat_pool, Node_Id gnat_node);
 706
 707 /* Build a GCC tree to correspond to allocating an object of TYPE whose
 708    initial value if INIT, if INIT is nonzero.  Convert the expression to
 709    RESULT_TYPE, which must be some type of pointer.  Return the tree.
 710    GNAT_PROC and GNAT_POOL optionally give the procedure to call and
 711    the storage pool to use.  GNAT_NODE is used to provide an error
 712    location for restriction violations messages.  */
 713 extern tree build_allocator (tree type, tree init, tree result_type,
 714                              Entity_Id gnat_proc, Entity_Id gnat_pool,
 715                              Node_Id gnat_node);
 716
 717 /* Fill in a VMS descriptor for EXPR and return a constructor for it.
 718    GNAT_FORMAL is how we find the descriptor record.  */
 719
 720 extern tree fill_vms_descriptor (tree expr, Entity_Id gnat_formal);
 721
 722 /* Indicate that we need to make the address of EXPR_NODE and it therefore
 723    should not be allocated in a register.  Return true if successful.  */
 724 extern bool gnat_mark_addressable (tree expr_node);
 725
 726 /* Implementation of the builtin_function langhook.  */
 727 extern tree builtin_function (const char *name, tree type, int function_code,
 728                               enum built_in_class class,
 729                               const char *library_name, tree attrs);
 730
 731 /* Search the chain of currently reachable declarations for a builtin
 732    FUNCTION_DECL node corresponding to function NAME (an IDENTIFIER_NODE).
 733    Return the first node found, if any, or NULL_TREE otherwise.  */
 734 extern tree builtin_decl_for (tree name ATTRIBUTE_UNUSED);
 735
 736 /* This function is called by the front end to enumerate all the supported
 737    modes for the machine.  We pass a function which is called back with
 738    the following integer parameters:
 739
 740    FLOAT_P      nonzero if this represents a floating-point mode
 741    COMPLEX_P    nonzero is this represents a complex mode
 742    COUNT        count of number of items, nonzero for vector mode
 743    PRECISION    number of bits in data representation
 744    MANTISSA     number of bits in mantissa, if FP and known, else zero.
 745    SIZE         number of bits used to store data
 746    ALIGN        number of bits to which mode is aligned.  */
 747 extern void enumerate_modes (void (*f) (int, int, int, int, int, int,
 748                                         unsigned int));
 749
 750 /* These are temporary function to deal with recent GCC changes related to
 751    FP type sizes and precisions.  */
 752 extern int fp_prec_to_size (int prec);
 753 extern int fp_size_to_prec (int size);
 754
 755 /* These functions return the basic data type sizes and related parameters
 756    about the target machine.  */
 757
 758 extern Pos get_target_bits_per_unit (void);
 759 extern Pos get_target_bits_per_word (void);
 760 extern Pos get_target_char_size (void);
 761 extern Pos get_target_wchar_t_size (void);
 762 extern Pos get_target_short_size (void);
 763 extern Pos get_target_int_size (void);
 764 extern Pos get_target_long_size (void);
 765 extern Pos get_target_long_long_size (void);
 766 extern Pos get_target_float_size (void);
 767 extern Pos get_target_double_size (void);
 768 extern Pos get_target_long_double_size (void);
 769 extern Pos get_target_pointer_size (void);
 770 extern Pos get_target_maximum_alignment (void);
 771 extern Nat get_float_words_be (void);
 772 extern Nat get_words_be (void);
 773 extern Nat get_bytes_be (void);
 774 extern Nat get_bits_be (void);
 775 extern Nat get_strict_alignment (void);