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) 1992-2008, 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,  51  Franklin  Street,  Fifth  Floor, *
  20  * Boston, MA 02110-1301, 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, an entity in the incoming GNAT tree, return a
  55    GCC type corresponding to that entity.  GNAT_ENTITY is assumed to
  56    refer to an Ada type.  */
  57 extern tree gnat_to_gnu_type (Entity_Id gnat_entity);
  58
  59 /* Given GNAT_ENTITY, a GNAT defining identifier node, which denotes some Ada
  60    entity, this routine returns the equivalent GCC tree for that entity
  61    (an ..._DECL node) and associates the ..._DECL node with the input GNAT
  62    defining identifier.
  63
  64    If GNAT_ENTITY is a variable or a constant declaration, GNU_EXPR gives its
  65    initial value (in GCC tree form). This is optional for variables.
  66    For renamed entities, GNU_EXPR gives the object being renamed.
  67
  68    DEFINITION is nonzero if this call is intended for a definition.  This is
  69    used for separate compilation where it necessary to know whether an
  70    external declaration or a definition should be created if the GCC equivalent
  71    was not created previously.  The value of 1 is normally used for a nonzero
  72    DEFINITION, but a value of 2 is used in special circumstances, defined in
  73    the code.  */
  74 extern tree gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr,
  75                                 int definition);
  76
  77 /* Similar, but if the returned value is a COMPONENT_REF, return the
  78    FIELD_DECL.  */
  79 extern tree gnat_to_gnu_field_decl (Entity_Id gnat_entity);
  80
  81 /* Wrap up compilation of T, a TYPE_DECL, possibly deferring it.  */
  82 extern void rest_of_type_decl_compilation (tree t);
  83
  84 /* Start a new statement group chained to the previous group.  */
  85 extern void start_stmt_group (void);
  86
  87 /* Add GNU_STMT to the current BLOCK_STMT node.  */
  88 extern void add_stmt (tree gnu_stmt);
  89
  90 /* Similar, but set the location of GNU_STMT to that of GNAT_NODE.  */
  91 extern void add_stmt_with_node (tree gnu_stmt, Node_Id gnat_node);
  92
  93 /* Return code corresponding to the current code group.  It is normally
  94    a STATEMENT_LIST, but may also be a BIND_EXPR or TRY_FINALLY_EXPR if
  95    BLOCK or cleanups were set.  */
  96 extern tree end_stmt_group (void);
  97
  98 /* Set the BLOCK node corresponding to the current code group to GNU_BLOCK.  */
  99 extern void set_block_for_group (tree);
 100
 101 /* Add a declaration statement for GNU_DECL to the current BLOCK_STMT node.
 102    Get SLOC from GNAT_ENTITY.  */
 103 extern void add_decl_expr (tree gnu_decl, Entity_Id gnat_entity);
 104
 105 /* Mark nodes rooted at *TP with TREE_VISITED and types as having their
 106    sized gimplified.  We use this to indicate all variable sizes and
 107    positions in global types may not be shared by any subprogram.  */
 108 extern void mark_visited (tree *);
 109
 110 /* Finalize any From_With_Type incomplete types.  We do this after processing
 111    our compilation unit and after processing its spec, if this is a body.  */
 112 extern void finalize_from_with_types (void);
 113
 114 /* Return the equivalent type to be used for GNAT_ENTITY, if it's a
 115    kind of type (such E_Task_Type) that has a different type which Gigi
 116    uses for its representation.  If the type does not have a special type
 117    for its representation, return GNAT_ENTITY.  If a type is supposed to
 118    exist, but does not, abort unless annotating types, in which case
 119    return Empty.   If GNAT_ENTITY is Empty, return Empty.  */
 120 extern Entity_Id Gigi_Equivalent_Type (Entity_Id);
 121
 122 /* Given GNAT_ENTITY, elaborate all expressions that are required to
 123    be elaborated at the point of its definition, but do nothing else.  */
 124 extern void elaborate_entity (Entity_Id gnat_entity);
 125
 126 /* Mark GNAT_ENTITY as going out of scope at this point.  Recursively mark
 127    any entities on its entity chain similarly.  */
 128 extern void mark_out_of_scope (Entity_Id gnat_entity);
 129
 130 /* Make a dummy type corresponding to GNAT_TYPE.  */
 131 extern tree make_dummy_type (Entity_Id gnat_type);
 132
 133 /* Get the unpadded version of a GNAT type.  */
 134 extern tree get_unpadded_type (Entity_Id gnat_entity);
 135
 136 /* Called when we need to protect a variable object using a save_expr.  */
 137 extern tree maybe_variable (tree gnu_operand);
 138
 139 /* Create a record type that contains a SIZE bytes long field of TYPE with a
 140     starting bit position so that it is aligned to ALIGN bits, and leaving at
 141     least ROOM bytes free before the field.  BASE_ALIGN is the alignment the
 142     record is guaranteed to get.  */
 143 extern tree make_aligning_type (tree type, unsigned int align, tree size,
 144                                 unsigned int base_align, int room);
 145
 146 /* Ensure that TYPE has SIZE and ALIGN.  Make and return a new padded type
 147    if needed.  We have already verified that SIZE and TYPE are large enough.
 148
 149    GNAT_ENTITY and NAME_TRAILER are used to name the resulting record and
 150    to issue a warning.
 151
 152    IS_USER_TYPE is true if we must be sure we complete the original type.
 153
 154    DEFINITION is true if this type is being defined.
 155
 156    SAME_RM_SIZE is true if the RM_Size of the resulting type is to be
 157    set to its TYPE_SIZE; otherwise, it's set to the RM_Size of the original
 158    type.  */
 159 extern tree maybe_pad_type (tree type, tree size, unsigned int align,
 160                             Entity_Id gnat_entity, const char *name_trailer,
 161                             bool is_user_type, bool definition,
 162                             bool same_rm_size);
 163
 164 /* Given a GNU tree and a GNAT list of choices, generate an expression to test
 165    the value passed against the list of choices.  */
 166 extern tree choices_to_gnu (tree operand, Node_Id choices);
 167
 168 /* Given a type T, a FIELD_DECL F, and a replacement value R, return a new
 169    type with all size expressions that contain F updated by replacing F
 170    with R.  If F is NULL_TREE, always make a new RECORD_TYPE, even if
 171    nothing has changed.  */
 172 extern tree substitute_in_type (tree t, tree f, tree r);
 173
 174 /* Return the "RM size" of GNU_TYPE.  This is the actual number of bits
 175    needed to represent the object.  */
 176 extern tree rm_size (tree gnu_type);
 177
 178 /* Given GNU_ID, an IDENTIFIER_NODE containing a name, and SUFFIX, a
 179    string, return a new IDENTIFIER_NODE that is the concatenation of
 180    the name in GNU_ID and SUFFIX.  */
 181 extern tree concat_id_with_name (tree gnu_id, const char *suffix);
 182
 183 /* Return the name to be used for GNAT_ENTITY.  If a type, create a
 184    fully-qualified name, possibly with type information encoding.
 185    Otherwise, return the name.  */
 186 extern tree get_entity_name (Entity_Id gnat_entity);
 187
 188 /* Return a name for GNAT_ENTITY concatenated with two underscores and
 189    SUFFIX.  */
 190 extern tree create_concat_name (Entity_Id gnat_entity, const char *suffix);
 191
 192 /* If true, then gigi is being called on an analyzed but unexpanded tree, and
 193    the only purpose of the call is to properly annotate types with
 194    representation information.  */
 195 extern bool type_annotate_only;
 196
 197 /* Current file name without path */
 198 extern const char *ref_filename;
 199
 200 /* This structure must be kept synchronized with Call_Back_End.  */
 201 struct File_Info_Type
 202 {
 203   File_Name_Type File_Name;
 204   Nat Num_Source_Lines;
 205 };
 206
 207 /* This is the main program of the back-end.  It sets up all the table
 208    structures and then generates code.
 209
 210    ??? Needs parameter descriptions  */
 211
 212 extern void gigi (Node_Id gnat_root, int max_gnat_node, int number_name,
 213                   struct Node *nodes_ptr, Node_Id *next_node_ptr,
 214                   Node_Id *prev_node_ptr, struct Elist_Header *elists_ptr,
 215                   struct Elmt_Item *elmts_ptr,
 216                   struct String_Entry *strings_ptr,
 217                   Char_Code *strings_chars_ptr,
 218                   struct List_Header *list_headers_ptr,
 219                   Nat number_file,
 220                   struct File_Info_Type *file_info_ptr,
 221                   Entity_Id standard_integer,
 222                   Entity_Id standard_long_long_float,
 223                   Entity_Id standard_exception_type,
 224                   Int gigi_operating_mode);
 225
 226 /* GNAT_NODE is the root of some GNAT tree.  Return the root of the
 227    GCC tree corresponding to that GNAT tree.  Normally, no code is generated;
 228    we just return an equivalent tree which is used elsewhere to generate
 229    code.  */
 230 extern tree gnat_to_gnu (Node_Id gnat_node);
 231
 232 /* GNU_STMT is a statement.  We generate code for that statement.  */
 233 extern void gnat_expand_stmt (tree gnu_stmt);
 234
 235 /* ??? missing documentation */
 236 extern int gnat_gimplify_expr (tree *expr_p, tree *pre_p,
 237                                tree *post_p ATTRIBUTE_UNUSED);
 238
 239 /* Do the processing for the declaration of a GNAT_ENTITY, a type.  If
 240    a separate Freeze node exists, delay the bulk of the processing.  Otherwise
 241    make a GCC type for GNAT_ENTITY and set up the correspondence.  */
 242 extern void process_type (Entity_Id gnat_entity);
 243
 244 /* Convert SLOC into LOCUS.  Return true if SLOC corresponds to a source code
 245    location and false if it doesn't.  In the former case, set the Gigi global
 246    variable REF_FILENAME to the simple debug file name as given by sinput.  */
 247 extern bool Sloc_to_locus (Source_Ptr Sloc, location_t *locus);
 248
 249 /* Post an error message.  MSG is the error message, properly annotated.
 250    NODE is the node at which to post the error and the node to use for the
 251    "&" substitution.  */
 252 extern void post_error (const char *, Node_Id);
 253
 254 /* Similar, but NODE is the node at which to post the error and ENT
 255    is the node to use for the "&" substitution.  */
 256 extern void post_error_ne (const char *msg, Node_Id node, Entity_Id ent);
 257
 258 /* Similar, but NODE is the node at which to post the error, ENT is the node
 259    to use for the "&" substitution, and N is the number to use for the ^.  */
 260 extern void post_error_ne_num (const char *msg, Node_Id node, Entity_Id ent,
 261                                int n);
 262
 263 /* Similar to post_error_ne_num, but T is a GCC tree representing the number
 264    to write.  If the tree represents a constant that fits within a
 265    host integer, the text inside curly brackets in MSG will be output
 266    (presumably including a '^').  Otherwise that text will not be output
 267    and the text inside square brackets will be output instead.  */
 268 extern void post_error_ne_tree (const char *msg, Node_Id node, Entity_Id ent,
 269                                 tree t);
 270
 271 /* Similar to post_error_ne_tree, except that NUM is a second
 272    integer to write in the message.  */
 273 extern void post_error_ne_tree_2 (const char *msg, Node_Id node, Entity_Id ent,
 274                                   tree t, int num);
 275
 276 /* Protect EXP from multiple evaluation.  This may make a SAVE_EXPR.  */
 277 extern tree protect_multiple_eval (tree exp);
 278
 279 /* Return a label to branch to for the exception type in KIND or NULL_TREE
 280    if none.  */
 281 extern tree get_exception_label (char);
 282
 283 /* Current node being treated, in case gigi_abort or Check_Elaboration_Code
 284    called.  */
 285 extern Node_Id error_gnat_node;
 286
 287 /* This is equivalent to stabilize_reference in tree.c, but we know how to
 288    handle our own nodes and we take extra arguments.  FORCE says whether to
 289    force evaluation of everything.  We set SUCCESS to true unless we walk
 290    through something we don't know how to stabilize.  */
 291 extern tree maybe_stabilize_reference (tree ref, bool force, bool *success);
 292
 293 /* Highest number in the front-end node table.  */
 294 extern int max_gnat_nodes;
 295
 296 /* If nonzero, pretend we are allocating at global level.  */
 297 extern int force_global;
 298
 299 /* Standard data type sizes.  Most of these are not used.  */
 300
 301 #ifndef CHAR_TYPE_SIZE
 302 #define CHAR_TYPE_SIZE BITS_PER_UNIT
 303 #endif
 304
 305 #ifndef SHORT_TYPE_SIZE
 306 #define SHORT_TYPE_SIZE (BITS_PER_UNIT * MIN ((UNITS_PER_WORD + 1) / 2, 2))
 307 #endif
 308
 309 #ifndef INT_TYPE_SIZE
 310 #define INT_TYPE_SIZE BITS_PER_WORD
 311 #endif
 312
 313 #ifndef LONG_TYPE_SIZE
 314 #define LONG_TYPE_SIZE BITS_PER_WORD
 315 #endif
 316
 317 #ifndef LONG_LONG_TYPE_SIZE
 318 #define LONG_LONG_TYPE_SIZE (BITS_PER_WORD * 2)
 319 #endif
 320
 321 #ifndef FLOAT_TYPE_SIZE
 322 #define FLOAT_TYPE_SIZE BITS_PER_WORD
 323 #endif
 324
 325 #ifndef DOUBLE_TYPE_SIZE
 326 #define DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
 327 #endif
 328
 329 #ifndef LONG_DOUBLE_TYPE_SIZE
 330 #define LONG_DOUBLE_TYPE_SIZE (BITS_PER_WORD * 2)
 331 #endif
 332
 333 /* The choice of SIZE_TYPE here is very problematic.  We need a signed
 334    type whose bit width is Pmode.  Assume "long" is such a type here.  */
 335 #undef SIZE_TYPE
 336 #define SIZE_TYPE "long int"
 337 \f
 338 /* Data structures used to represent attributes.  */
 339
 340 enum attr_type
 341 {
 342   ATTR_MACHINE_ATTRIBUTE,
 343   ATTR_LINK_ALIAS,
 344   ATTR_LINK_SECTION,
 345   ATTR_LINK_CONSTRUCTOR,
 346   ATTR_LINK_DESTRUCTOR,
 347   ATTR_WEAK_EXTERNAL
 348 };
 349
 350 struct attrib
 351 {
 352   struct attrib *next;
 353   enum attr_type type;
 354   tree name;
 355   tree args;
 356   Node_Id error_point;
 357 };
 358
 359 /* Table of machine-independent internal attributes.  */
 360 extern const struct attribute_spec gnat_internal_attribute_table[];
 361
 362 /* Define the entries in the standard data array.  */
 363 enum standard_datatypes
 364 {
 365 /* Various standard data types and nodes.  */
 366   ADT_longest_float_type,
 367   ADT_void_type_decl,
 368
 369   /* The type of an exception.  */
 370   ADT_except_type,
 371
 372   /* Type declaration node  <==> typedef void *T */
 373   ADT_ptr_void_type,
 374
 375   /* Function type declaration -- void T() */
 376   ADT_void_ftype,
 377
 378   /* Type declaration node  <==> typedef void *T() */
 379   ADT_ptr_void_ftype,
 380
 381   /* Type declaration node  <==> typedef virtual void *T() */
 382   ADT_fdesc_type,
 383
 384   /* Null pointer for above type */
 385   ADT_null_fdesc,
 386
 387   /* Function declaration nodes for run-time functions for allocating memory.
 388      Ada allocators cause calls to these functions to be generated.  Malloc32
 389      is used only on 64bit systems needing to allocate 32bit memory. */
 390   ADT_malloc_decl,
 391   ADT_malloc32_decl,
 392
 393   /* Likewise for freeing memory.  */
 394   ADT_free_decl,
 395
 396   /* Types and decls used by our temporary exception mechanism.  See
 397      init_gigi_decls for details.  */
 398   ADT_jmpbuf_type,
 399   ADT_jmpbuf_ptr_type,
 400   ADT_get_jmpbuf_decl,
 401   ADT_set_jmpbuf_decl,
 402   ADT_get_excptr_decl,
 403   ADT_setjmp_decl,
 404   ADT_longjmp_decl,
 405   ADT_update_setjmp_buf_decl,
 406   ADT_raise_nodefer_decl,
 407   ADT_begin_handler_decl,
 408   ADT_end_handler_decl,
 409   ADT_others_decl,
 410   ADT_all_others_decl,
 411   ADT_LAST};
 412
 413 extern GTY(()) tree gnat_std_decls[(int) ADT_LAST];
 414 extern GTY(()) tree gnat_raise_decls[(int) LAST_REASON_CODE + 1];
 415
 416 #define longest_float_type_node gnat_std_decls[(int) ADT_longest_float_type]
 417 #define void_type_decl_node gnat_std_decls[(int) ADT_void_type_decl]
 418 #define except_type_node gnat_std_decls[(int) ADT_except_type]
 419 #define ptr_void_type_node gnat_std_decls[(int) ADT_ptr_void_type]
 420 #define void_ftype gnat_std_decls[(int) ADT_void_ftype]
 421 #define ptr_void_ftype gnat_std_decls[(int) ADT_ptr_void_ftype]
 422 #define fdesc_type_node gnat_std_decls[(int) ADT_fdesc_type]
 423 #define null_fdesc_node gnat_std_decls[(int) ADT_null_fdesc]
 424 #define malloc_decl gnat_std_decls[(int) ADT_malloc_decl]
 425 #define malloc32_decl gnat_std_decls[(int) ADT_malloc32_decl]
 426 #define free_decl gnat_std_decls[(int) ADT_free_decl]
 427 #define jmpbuf_type gnat_std_decls[(int) ADT_jmpbuf_type]
 428 #define jmpbuf_ptr_type gnat_std_decls[(int) ADT_jmpbuf_ptr_type]
 429 #define get_jmpbuf_decl gnat_std_decls[(int) ADT_get_jmpbuf_decl]
 430 #define set_jmpbuf_decl gnat_std_decls[(int) ADT_set_jmpbuf_decl]
 431 #define get_excptr_decl gnat_std_decls[(int) ADT_get_excptr_decl]
 432 #define setjmp_decl gnat_std_decls[(int) ADT_setjmp_decl]
 433 #define longjmp_decl gnat_std_decls[(int) ADT_longjmp_decl]
 434 #define update_setjmp_buf_decl gnat_std_decls[(int) ADT_update_setjmp_buf_decl]
 435 #define raise_nodefer_decl gnat_std_decls[(int) ADT_raise_nodefer_decl]
 436 #define begin_handler_decl gnat_std_decls[(int) ADT_begin_handler_decl]
 437 #define others_decl gnat_std_decls[(int) ADT_others_decl]
 438 #define all_others_decl gnat_std_decls[(int) ADT_all_others_decl]
 439 #define end_handler_decl gnat_std_decls[(int) ADT_end_handler_decl]
 440
 441 /* Routines expected by the gcc back-end. They must have exactly the same
 442    prototype and names as below.  */
 443
 444 /* Returns nonzero if we are currently in the global binding level.  */
 445 extern int global_bindings_p (void);
 446
 447 /* Enter and exit a new binding level. */
 448 extern void gnat_pushlevel (void);
 449 extern void gnat_poplevel (void);
 450
 451 /* Set SUPERCONTEXT of the BLOCK for the current binding level to FNDECL
 452    and point FNDECL to this BLOCK.  */
 453 extern void set_current_block_context (tree fndecl);
 454
 455 /* Set the jmpbuf_decl for the current binding level to DECL.  */
 456 extern void set_block_jmpbuf_decl (tree decl);
 457
 458 /* Get the setjmp_decl, if any, for the current binding level.  */
 459 extern tree get_block_jmpbuf_decl (void);
 460
 461 /* Records a ..._DECL node DECL as belonging to the current lexical scope
 462    and uses GNAT_NODE for location information.  */
 463 extern void gnat_pushdecl (tree decl, Node_Id gnat_node);
 464
 465 extern void gnat_init_decl_processing (void);
 466 extern void init_gigi_decls (tree long_long_float_type, tree exception_type);
 467 extern void gnat_init_gcc_eh (void);
 468
 469 /* Return an integer type with the number of bits of precision given by
 470    PRECISION.  UNSIGNEDP is nonzero if the type is unsigned; otherwise
 471    it is a signed type.  */
 472 extern tree gnat_type_for_size (unsigned precision, int unsignedp);
 473
 474 /* Return a data type that has machine mode MODE.  UNSIGNEDP selects
 475    an unsigned type; otherwise a signed type is returned.  */
 476 extern tree gnat_type_for_mode (enum machine_mode mode, int unsignedp);
 477
 478 /* Emit debug info for all global variable declarations.  */
 479 extern void gnat_write_global_declarations (void);
 480
 481 /* Return the unsigned version of a TYPE_NODE, a scalar type.  */
 482 extern tree gnat_unsigned_type (tree type_node);
 483
 484 /* Return the signed version of a TYPE_NODE, a scalar type.  */
 485 extern tree gnat_signed_type (tree type_node);
 486
 487 /* Return 1 if the types T1 and T2 are compatible, i.e. if they can be
 488    transparently converted to each other.  */
 489 extern int gnat_types_compatible_p (tree t1, tree t2);
 490
 491 /* Create an expression whose value is that of EXPR,
 492    converted to type TYPE.  The TREE_TYPE of the value
 493    is always TYPE.  This function implements all reasonable
 494    conversions; callers should filter out those that are
 495    not permitted by the language being compiled.  */
 496 extern tree convert (tree type, tree expr);
 497
 498 /* Routines created solely for the tree translator's sake. Their prototypes
 499    can be changed as desired.  */
 500
 501 /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
 502    GNU_DECL is the GCC tree which is to be associated with
 503    GNAT_ENTITY. Such gnu tree node is always an ..._DECL node.
 504    If NO_CHECK is nonzero, the latter check is suppressed.
 505    If GNU_DECL is zero, a previous association is to be reset.  */
 506 extern void save_gnu_tree (Entity_Id gnat_entity, tree gnu_decl,
 507                            bool no_check);
 508
 509 /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
 510    Return the ..._DECL node that was associated with it.  If there is no tree
 511    node associated with GNAT_ENTITY, abort.  */
 512 extern tree get_gnu_tree (Entity_Id gnat_entity);
 513
 514 /* Return nonzero if a GCC tree has been associated with GNAT_ENTITY.  */
 515 extern bool present_gnu_tree (Entity_Id gnat_entity);
 516
 517 /* Initialize tables for above routines.  */
 518 extern void init_gnat_to_gnu (void);
 519
 520 /* Given a record type RECORD_TYPE and a chain of FIELD_DECL nodes FIELDLIST,
 521    finish constructing the record or union type.  If REP_LEVEL is zero, this
 522    record has no representation clause and so will be entirely laid out here.
 523    If REP_LEVEL is one, this record has a representation clause and has been
 524    laid out already; only set the sizes and alignment.  If REP_LEVEL is two,
 525    this record is derived from a parent record and thus inherits its layout;
 526    only make a pass on the fields to finalize them.  If DO_NOT_FINALIZE is
 527    true, the record type is expected to be modified afterwards so it will
 528    not be sent to the back-end for finalization.  */
 529 extern void finish_record_type (tree record_type, tree fieldlist,
 530                                 int rep_level, bool do_not_finalize);
 531
 532 /* Wrap up compilation of RECORD_TYPE, i.e. most notably output all
 533    the debug information associated with it.  It need not be invoked
 534    directly in most cases since finish_record_type takes care of doing
 535    so, unless explicitly requested not to through DO_NOT_FINALIZE.  */
 536 extern void rest_of_record_type_compilation (tree record_type);
 537
 538 /* Returns a FUNCTION_TYPE node. RETURN_TYPE is the type returned by the
 539    subprogram. If it is void_type_node, then we are dealing with a procedure,
 540    otherwise we are dealing with a function. PARAM_DECL_LIST is a list of
 541    PARM_DECL nodes that are the subprogram arguments.  CICO_LIST is the
 542    copy-in/copy-out list to be stored into TYPE_CI_CO_LIST.
 543    RETURNS_UNCONSTRAINED is true if the function returns an unconstrained
 544    object.  RETURNS_BY_REF is true if the function returns by reference.
 545    RETURNS_BY_TARGET_PTR is true if the function is to be passed (as its
 546    first parameter) the address of the place to copy its result.  */
 547 extern tree create_subprog_type (tree return_type, tree param_decl_list,
 548                                  tree cico_list, bool returns_unconstrained,
 549                                  bool returns_by_ref,
 550                                  bool returns_by_target_ptr);
 551
 552 /* Return a copy of TYPE, but safe to modify in any way.  */
 553 extern tree copy_type (tree type);
 554
 555 /* Return an INTEGER_TYPE of SIZETYPE with range MIN to MAX and whose
 556    TYPE_INDEX_TYPE is INDEX.  GNAT_NODE is used for the position of
 557    the decl.  */
 558 extern tree create_index_type (tree min, tree max, tree index,
 559                                Node_Id gnat_node);
 560
 561 /* Return a TYPE_DECL node. TYPE_NAME gives the name of the type (a character
 562    string) and TYPE is a ..._TYPE node giving its data type.
 563    ARTIFICIAL_P is true if this is a declaration that was generated
 564    by the compiler.  DEBUG_INFO_P is true if we need to write debugging
 565    information about this type.  GNAT_NODE is used for the position of
 566    the decl.  */
 567 extern tree create_type_decl (tree type_name, tree type,
 568                               struct attrib *attr_list,
 569                               bool artificial_p, bool debug_info_p,
 570                               Node_Id gnat_node);
 571
 572 /* Return a VAR_DECL or CONST_DECL node.
 573
 574    VAR_NAME gives the name of the variable.  ASM_NAME is its assembler name
 575    (if provided).  TYPE is its data type (a GCC ..._TYPE node).  VAR_INIT is
 576    the GCC tree for an optional initial expression; NULL_TREE if none.
 577
 578    CONST_FLAG is true if this variable is constant, in which case we might
 579    return a CONST_DECL node unless CONST_DECL_ALLOWED_P is false.
 580
 581    PUBLIC_FLAG is true if this definition is to be made visible outside of
 582    the current compilation unit. This flag should be set when processing the
 583    variable definitions in a package specification.
 584
 585    EXTERN_FLAG is nonzero when processing an external variable declaration (as
 586    opposed to a definition: no storage is to be allocated for the variable).
 587
 588    STATIC_FLAG is only relevant when not at top level.  In that case
 589    it indicates whether to always allocate storage to the variable.
 590
 591    GNAT_NODE is used for the position of the decl.  */
 592 tree
 593 create_var_decl_1 (tree var_name, tree asm_name, tree type, tree var_init,
 594                    bool const_flag, bool public_flag, bool extern_flag,
 595                    bool static_flag, bool const_decl_allowed_p,
 596                    struct attrib *attr_list, Node_Id gnat_node);
 597
 598 /* Wrapper around create_var_decl_1 for cases where we don't care whether
 599    a VAR or a CONST decl node is created.  */
 600 #define create_var_decl(var_name, asm_name, type, var_init,     \
 601                         const_flag, public_flag, extern_flag,   \
 602                         static_flag, attr_list, gnat_node)      \
 603   create_var_decl_1 (var_name, asm_name, type, var_init,        \
 604                      const_flag, public_flag, extern_flag,      \
 605                      static_flag, true, attr_list, gnat_node)
 606
 607 /* Wrapper around create_var_decl_1 for cases where a VAR_DECL node is
 608    required.  The primary intent is for DECL_CONST_CORRESPONDING_VARs, which
 609    must be VAR_DECLs and on which we want TREE_READONLY set to have them
 610    possibly assigned to a readonly data section.  */
 611 #define create_true_var_decl(var_name, asm_name, type, var_init,        \
 612                              const_flag, public_flag, extern_flag,      \
 613                              static_flag, attr_list, gnat_node)         \
 614   create_var_decl_1 (var_name, asm_name, type, var_init,                \
 615                      const_flag, public_flag, extern_flag,              \
 616                      static_flag, false, attr_list, gnat_node)
 617
 618 /* Given a DECL and ATTR_LIST, apply the listed attributes.  */
 619 extern void process_attributes (tree decl, struct attrib *attr_list);
 620
 621 /* Record a global renaming pointer.  */
 622 void record_global_renaming_pointer (tree);
 623
 624 /* Invalidate the global renaming pointers.   */
 625 void invalidate_global_renaming_pointers (void);
 626
 627 /* Returns a FIELD_DECL node. FIELD_NAME the field name, FIELD_TYPE is its
 628    type, and RECORD_TYPE is the type of the parent.  PACKED is nonzero if
 629    this field is in a record type with a "pragma pack".  If SIZE is nonzero
 630    it is the specified size for this field.  If POS is nonzero, it is the bit
 631    position.  If ADDRESSABLE is nonzero, it means we are allowed to take
 632    the address of this field for aliasing purposes.  */
 633 extern tree create_field_decl (tree field_name, tree field_type,
 634                                tree record_type, int packed, tree size,
 635                                tree pos, int addressable);
 636
 637 /* Returns a PARM_DECL node. PARAM_NAME is the name of the parameter,
 638    PARAM_TYPE is its type.  READONLY is true if the parameter is
 639    readonly (either an In parameter or an address of a pass-by-ref
 640    parameter). */
 641 extern tree create_param_decl (tree param_name, tree param_type,
 642                                bool readonly);
 643
 644 /* Returns a FUNCTION_DECL node.  SUBPROG_NAME is the name of the subprogram,
 645    ASM_NAME is its assembler name, SUBPROG_TYPE is its type (a FUNCTION_TYPE
 646    node), PARAM_DECL_LIST is the list of the subprogram arguments (a list of
 647    PARM_DECL nodes chained through the TREE_CHAIN field).
 648
 649    INLINE_FLAG, PUBLIC_FLAG, EXTERN_FLAG, and ATTR_LIST are used to set the
 650    appropriate fields in the FUNCTION_DECL.  GNAT_NODE gives the location.  */
 651 extern tree create_subprog_decl (tree subprog_name, tree asm_name,
 652                                  tree subprog_type, tree param_decl_list,
 653                                  bool inlinee_flag, bool public_flag,
 654                                  bool extern_flag,
 655                                  struct attrib *attr_list, Node_Id gnat_node);
 656
 657 /* Returns a LABEL_DECL node for LABEL_NAME.  */
 658 extern tree create_label_decl (tree label_name);
 659
 660 /* Set up the framework for generating code for SUBPROG_DECL, a subprogram
 661    body. This routine needs to be invoked before processing the declarations
 662    appearing in the subprogram.  */
 663 extern void begin_subprog_body (tree subprog_decl);
 664
 665 /* Finish the definition of the current subprogram and compile it all the way
 666    to assembler language output.  BODY is the tree corresponding to
 667    the subprogram.  */
 668 extern void end_subprog_body (tree body);
 669
 670 /* Build a template of type TEMPLATE_TYPE from the array bounds of ARRAY_TYPE.
 671    EXPR is an expression that we can use to locate any PLACEHOLDER_EXPRs.
 672    Return a constructor for the template.  */
 673 extern tree build_template (tree template_type, tree array_type, tree expr);
 674
 675 /* Build a VMS descriptor from a Mechanism_Type, which must specify
 676    a descriptor type, and the GCC type of an object.  Each FIELD_DECL
 677    in the type contains in its DECL_INITIAL the expression to use when
 678    a constructor is made for the type.  GNAT_ENTITY is a gnat node used
 679    to print out an error message if the mechanism cannot be applied to
 680    an object of that type and also for the name.  */
 681 extern tree build_vms_descriptor (tree type, Mechanism_Type mech,
 682                                   Entity_Id gnat_entity);
 683
 684 /* Build a stub for the subprogram specified by the GCC tree GNU_SUBPROG
 685    and the GNAT node GNAT_SUBPROG.  */
 686 extern void build_function_stub (tree gnu_subprog, Entity_Id gnat_subprog);
 687
 688 /* Build a type to be used to represent an aliased object whose nominal
 689    type is an unconstrained array.  This consists of a RECORD_TYPE containing
 690    a field of TEMPLATE_TYPE and a field of OBJECT_TYPE, which is an
 691    ARRAY_TYPE.  If ARRAY_TYPE is that of the unconstrained array, this
 692    is used to represent an arbitrary unconstrained object.  Use NAME
 693    as the name of the record.  */
 694 extern tree build_unc_object_type (tree template_type, tree object_type,
 695                                    tree name);
 696
 697 /* Same as build_unc_object_type, but taking a thin or fat pointer type
 698    instead of the template type. */
 699 extern tree build_unc_object_type_from_ptr (tree thin_fat_ptr_type,
 700                                             tree object_type, tree name);
 701
 702 /* Shift the component offsets within an unconstrained object TYPE to make it
 703    suitable for use as a designated type for thin pointers.  */
 704 extern void shift_unc_components_for_thin_pointers (tree type);
 705
 706 /* Update anything previously pointing to OLD_TYPE to point to NEW_TYPE.  In
 707    the normal case this is just two adjustments, but we have more to do
 708    if NEW is an UNCONSTRAINED_ARRAY_TYPE.  */
 709 extern void update_pointer_to (tree old_type, tree new_type);
 710
 711 /* EXP is an expression for the size of an object.  If this size contains
 712    discriminant references, replace them with the maximum (if MAX_P) or
 713    minimum (if !MAX_P) possible value of the discriminant.  */
 714 extern tree max_size (tree exp, bool max_p);
 715
 716 /* Remove all conversions that are done in EXP.  This includes converting
 717    from a padded type or to a left-justified modular type.  If TRUE_ADDRESS
 718    is true, always return the address of the containing object even if
 719    the address is not bit-aligned.  */
 720 extern tree remove_conversions (tree exp, bool true_address);
 721
 722 /* If EXP's type is an UNCONSTRAINED_ARRAY_TYPE, return an expression that
 723    refers to the underlying array.  If its type has TYPE_CONTAINS_TEMPLATE_P,
 724    likewise return an expression pointing to the underlying array.  */
 725 extern tree maybe_unconstrained_array (tree exp);
 726
 727 /* Return an expression that does an unchecked conversion of EXPR to TYPE.
 728    If NOTRUNC_P is true, truncation operations should be suppressed.  */
 729 extern tree unchecked_convert (tree type, tree expr, bool notrunc_p);
 730
 731 /* Return the appropriate GCC tree code for the specified GNAT type,
 732    the latter being a record type as predicated by Is_Record_Type.  */
 733 extern enum tree_code tree_code_for_record_type (Entity_Id);
 734
 735 /* Return true if GNU_TYPE is suitable as the type of a non-aliased
 736    component of an aggregate type.  */
 737 extern bool type_for_nonaliased_component_p (tree);
 738
 739 /* Prepare expr to be an argument of a TRUTH_NOT_EXPR or other logical
 740    operation.
 741
 742    This preparation consists of taking the ordinary
 743    representation of an expression EXPR and producing a valid tree
 744    boolean expression describing whether EXPR is nonzero.  We could
 745    simply always do build_binary_op (NE_EXPR, expr, integer_zero_node, 1),
 746    but we optimize comparisons, &&, ||, and !.
 747
 748    The resulting type should always be the same as the input type.
 749    This function is simpler than the corresponding C version since
 750    the only possible operands will be things of Boolean type.  */
 751 extern tree gnat_truthvalue_conversion (tree expr);
 752
 753 /* Return the base type of TYPE.  */
 754 extern tree get_base_type (tree type);
 755
 756 /* EXP is a GCC tree representing an address.  See if we can find how
 757    strictly the object at that address is aligned.   Return that alignment
 758    strictly the object at that address is aligned.   Return that alignment
 759    in bits.  If we don't know anything about the alignment, return 0.  */
 760 extern unsigned int known_alignment (tree exp);
 761
 762 /* Return true if VALUE is a multiple of FACTOR. FACTOR must be a power
 763    of 2. */
 764 extern bool value_factor_p (tree value, HOST_WIDE_INT factor);
 765
 766 /* Make a binary operation of kind OP_CODE.  RESULT_TYPE is the type
 767    desired for the result.  Usually the operation is to be performed
 768    in that type.  For MODIFY_EXPR and ARRAY_REF, RESULT_TYPE may be 0
 769    in which case the type to be used will be derived from the operands.  */
 770 extern tree build_binary_op (enum tree_code op_code, tree retult_type,
 771                              tree left_operand, tree right_operand);
 772
 773 /* Similar, but make unary operation.   */
 774 extern tree build_unary_op (enum tree_code op_code, tree result_type,
 775                             tree operand);
 776
 777 /* Similar, but for COND_EXPR.  */
 778 extern tree build_cond_expr (tree result_type, tree condition_operand,
 779                              tree true_operand, tree false_operand);
 780
 781 /* Similar, but for RETURN_EXPR.  */
 782 extern tree build_return_expr (tree result_decl, tree ret_val);
 783
 784 /* Build a CALL_EXPR to call FUNDECL with one argument, ARG.  Return
 785    the CALL_EXPR.  */
 786 extern tree build_call_1_expr (tree fundecl, tree arg);
 787
 788 /* Build a CALL_EXPR to call FUNDECL with two argument, ARG1 & ARG2.  Return
 789    the CALL_EXPR.  */
 790 extern tree build_call_2_expr (tree fundecl, tree arg1, tree arg2);
 791
 792 /* Likewise to call FUNDECL with no arguments.  */
 793 extern tree build_call_0_expr (tree fundecl);
 794
 795 /* Call a function that raises an exception and pass the line number and file
 796    name, if requested.  MSG says which exception function to call.
 797
 798    GNAT_NODE is the gnat node conveying the source location for which the
 799    error should be signaled, or Empty in which case the error is signaled on
 800    the current ref_file_name/input_line.
 801
 802    KIND says which kind of exception this is for
 803     (N_Raise_{Constraint,Storage,Program}_Error).  */
 804 extern tree build_call_raise (int msg, Node_Id gnat_node, char kind);
 805
 806 /* Return a CONSTRUCTOR of TYPE whose list is LIST.  This is not the
 807    same as build_constructor in the language-independent tree.c.  */
 808 extern tree gnat_build_constructor (tree type, tree list);
 809
 810 /* Return a COMPONENT_REF to access a field that is given by COMPONENT,
 811    an IDENTIFIER_NODE giving the name of the field, FIELD, a FIELD_DECL,
 812    for the field, or both.  Don't fold the result if NO_FOLD_P.  */
 813 extern tree build_component_ref (tree record_variable, tree component,
 814                                  tree field, bool no_fold_p);
 815
 816 /* Build a GCC tree to call an allocation or deallocation function.
 817    If GNU_OBJ is nonzero, it is an object to deallocate.  Otherwise,
 818    generate an allocator.
 819
 820    GNU_SIZE is the size of the object and ALIGN is the alignment.
 821    GNAT_PROC, if present is a procedure to call and GNAT_POOL is the
 822    storage pool to use.  If not preset, malloc and free will be used.  */
 823 extern tree build_call_alloc_dealloc (tree gnu_obj, tree gnu_size,
 824                                       unsigned align, Entity_Id gnat_proc,
 825                                       Entity_Id gnat_pool, Node_Id gnat_node);
 826
 827 /* Build a GCC tree to correspond to allocating an object of TYPE whose
 828    initial value if INIT, if INIT is nonzero.  Convert the expression to
 829    RESULT_TYPE, which must be some type of pointer.  Return the tree.
 830    GNAT_PROC and GNAT_POOL optionally give the procedure to call and
 831    the storage pool to use.  GNAT_NODE is used to provide an error
 832    location for restriction violations messages.  If IGNORE_INIT_TYPE is
 833    true, ignore the type of INIT for the purpose of determining the size;
 834    this will cause the maximum size to be allocated if TYPE is of
 835    self-referential size.  */
 836 extern tree build_allocator (tree type, tree init, tree result_type,
 837                              Entity_Id gnat_proc, Entity_Id gnat_pool,
 838                              Node_Id gnat_node, bool);
 839
 840 /* Fill in a VMS descriptor for EXPR and return a constructor for it.
 841    GNAT_FORMAL is how we find the descriptor record.  */
 842
 843 extern tree fill_vms_descriptor (tree expr, Entity_Id gnat_formal);
 844
 845 /* Indicate that we need to make the address of EXPR_NODE and it therefore
 846    should not be allocated in a register.  Return true if successful.  */
 847 extern bool gnat_mark_addressable (tree expr_node);
 848
 849 /* Implementation of the builtin_function langhook.  */
 850 extern tree gnat_builtin_function (tree decl);
 851
 852 /* Search the chain of currently reachable declarations for a builtin
 853    FUNCTION_DECL node corresponding to function NAME (an IDENTIFIER_NODE).
 854    Return the first node found, if any, or NULL_TREE otherwise.  */
 855 extern tree builtin_decl_for (tree name);
 856
 857 /* This function is called by the front end to enumerate all the supported
 858    modes for the machine.  We pass a function which is called back with
 859    the following integer parameters:
 860
 861    FLOAT_P      nonzero if this represents a floating-point mode
 862    COMPLEX_P    nonzero is this represents a complex mode
 863    COUNT        count of number of items, nonzero for vector mode
 864    PRECISION    number of bits in data representation
 865    MANTISSA     number of bits in mantissa, if FP and known, else zero.
 866    SIZE         number of bits used to store data
 867    ALIGN        number of bits to which mode is aligned.  */
 868 extern void enumerate_modes (void (*f) (int, int, int, int, int, int,
 869                                         unsigned int));
 870
 871 /* These are temporary function to deal with recent GCC changes related to
 872    FP type sizes and precisions.  */
 873 extern int fp_prec_to_size (int prec);
 874 extern int fp_size_to_prec (int size);
 875
 876 /* These functions return the basic data type sizes and related parameters
 877    about the target machine.  */
 878
 879 extern Pos get_target_bits_per_unit (void);
 880 extern Pos get_target_bits_per_word (void);
 881 extern Pos get_target_char_size (void);
 882 extern Pos get_target_wchar_t_size (void);
 883 extern Pos get_target_short_size (void);
 884 extern Pos get_target_int_size (void);
 885 extern Pos get_target_long_size (void);
 886 extern Pos get_target_long_long_size (void);
 887 extern Pos get_target_float_size (void);
 888 extern Pos get_target_double_size (void);
 889 extern Pos get_target_long_double_size (void);
 890 extern Pos get_target_pointer_size (void);
 891 extern Pos get_target_maximum_alignment (void);
 892 extern Pos get_target_default_allocator_alignment (void);
 893 extern Pos get_target_maximum_default_alignment (void);
 894 extern Pos get_target_maximum_allowed_alignment (void);
 895 extern Nat get_float_words_be (void);
 896 extern Nat get_words_be (void);
 897 extern Nat get_bytes_be (void);
 898 extern Nat get_bits_be (void);
 899 extern Nat get_strict_alignment (void);