1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S E M _ A T T R -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2015, 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 3, 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. -- 17-- -- 18-- You should have received a copy of the GNU General Public License along -- 19-- with this program; see file COPYING3. If not see -- 20-- <http://www.gnu.org/licenses/>. -- 21-- -- 22-- GNAT was originally developed by the GNAT team at New York University. -- 23-- Extensive contributions were provided by Ada Core Technologies Inc. -- 24-- -- 25------------------------------------------------------------------------------ 26 27-- Attribute handling is isolated in a separate package to ease the addition 28-- of implementation defined attributes. Logically this processing belongs 29-- in chapter 4. See Sem_Ch4 for a description of the relation of the 30-- Analyze and Resolve routines for expression components. 31 32-- This spec also documents all GNAT implementation defined pragmas 33 34with Exp_Tss; use Exp_Tss; 35with Namet; use Namet; 36with Snames; use Snames; 37with Types; use Types; 38 39package Sem_Attr is 40 41 ----------------------------------------- 42 -- Implementation Dependent Attributes -- 43 ----------------------------------------- 44 45 -- This section describes the implementation dependent attributes provided 46 -- in GNAT, as well as constructing an array of flags indicating which 47 -- attributes these are. 48 49 Attribute_Impl_Def : Attribute_Class_Array := Attribute_Class_Array'( 50 51 ------------------ 52 -- Abort_Signal -- 53 ------------------ 54 55 Attribute_Abort_Signal => True, 56 -- Standard'Abort_Signal (Standard is the only allowed prefix) provides 57 -- the entity for the special exception used to signal task abort or 58 -- asynchronous transfer of control. Normally this attribute should only 59 -- be used in the tasking runtime (it is highly peculiar, and completely 60 -- outside the normal semantics of Ada, for a user program to intercept 61 -- the abort exception). 62 63 ------------------ 64 -- Address_Size -- 65 ------------------ 66 67 Attribute_Address_Size => True, 68 -- Standard'Address_Size (Standard is the only allowed prefix) is 69 -- a static constant giving the number of bits in an Address. It 70 -- is used primarily for constructing the definition of Memory_Size 71 -- in package Standard, but may be freely used in user programs. 72 -- This is a static attribute. 73 74 --------------- 75 -- Asm_Input -- 76 --------------- 77 78 Attribute_Asm_Input => True, 79 -- Used only in conjunction with the Asm subprograms in package 80 -- Machine_Code to construct machine instructions. See documentation 81 -- in package Machine_Code in file s-maccod.ads. 82 83 ---------------- 84 -- Asm_Output -- 85 ---------------- 86 87 Attribute_Asm_Output => True, 88 -- Used only in conjunction with the Asm subprograms in package 89 -- Machine_Code to construct machine instructions. See documentation 90 -- in package Machine_Code in file s-maccod.ads. 91 92 --------- 93 -- Bit -- 94 --------- 95 96 Attribute_Bit => True, 97 -- Obj'Bit, where Obj is any object, yields the bit offset within the 98 -- storage unit (byte) that contains the first bit of storage allocated 99 -- for the object. The attribute value is of type Universal_Integer, 100 -- and is always a non-negative number not exceeding the value of 101 -- System.Storage_Unit. 102 -- 103 -- For an object that is a variable or a constant allocated in a 104 -- register, the value is zero. (The use of this attribute does not 105 -- force the allocation of a variable to memory). 106 -- 107 -- For an object that is a formal parameter, this attribute applies to 108 -- either the matching actual parameter or to a copy of the matching 109 -- actual parameter. 110 -- 111 -- For an access object the value is zero. Note that Obj.all'Bit is 112 -- subject to an Access_Check for the designated object. Similarly 113 -- for a record component X.C'Bit is subject to a discriminant check 114 -- and X(I).Bit and X(I1..I2)'Bit are subject to index checks. 115 -- 116 -- This attribute is designed to be compatible with the DEC Ada 117 -- definition and implementation of the Bit attribute. 118 119 ------------------ 120 -- Code_Address -- 121 ------------------ 122 123 Attribute_Code_Address => True, 124 -- The reference subp'Code_Address, where subp is a subprogram entity, 125 -- gives the address of the first generated instruction for the sub- 126 -- program. This is often, but not always the same as the 'Address 127 -- value, which is the address to be used in a call. The differences 128 -- occur in the case of a nested procedure (where Address yields the 129 -- address of the trampoline code used to load the static link), and on 130 -- some systems which use procedure descriptors (in which case Address 131 -- yields the address of the descriptor). 132 133 ----------------------- 134 -- Default_Bit_Order -- 135 ----------------------- 136 137 Attribute_Default_Bit_Order => True, 138 -- Standard'Default_Bit_Order (Standard is the only permissible prefix) 139 -- provides the value System.Default_Bit_Order as a Pos value (0 for 140 -- High_Order_First, 1 for Low_Order_First). This is used to construct 141 -- the definition of Default_Bit_Order in package System. This is a 142 -- static attribute. 143 144 ---------------------------------- 145 -- Default_Scalar_Storage_Order -- 146 ---------------------------------- 147 148 Attribute_Default_Scalar_Storage_Order => True, 149 -- Standard'Default_Scalar_Storage_Order (Standard is the 150 -- only permissible prefix) provides the current value of the 151 -- default scalar storage order (as specified using pragma 152 -- Default_Scalar_Storage_Order, or equal to Default_Bit_Order if 153 -- unspecified) as a System.Bit_Order value. This is a static attribute. 154 155 ----------- 156 -- Deref -- 157 ----------- 158 159 Attribute_Deref => True, 160 -- typ'Deref (expr) is valid only if expr is of type System'Address. 161 -- The result is an object of type typ that is obtained by treating the 162 -- address as an access-to-typ value that points to the result. It is 163 -- basically equivalent to (atyp!expr).all where atyp is an access type 164 -- for the type. 165 166 --------------- 167 -- Elab_Body -- 168 --------------- 169 170 Attribute_Elab_Body => True, 171 -- This attribute can only be applied to a program unit name. It 172 -- returns the entity for the corresponding elaboration procedure for 173 -- elaborating the body of the referenced unit. This is used in the main 174 -- generated elaboration procedure by the binder, and is not normally 175 -- used in any other context, but there may be specialized situations in 176 -- which it is useful to be able to call this elaboration procedure from 177 -- Ada code, e.g. if it is necessary to do selective reelaboration to 178 -- fix some error. 179 180 -------------------- 181 -- Elab_Subp_Body -- 182 -------------------- 183 184 Attribute_Elab_Subp_Body => True, 185 -- This attribute can only be applied to a library level subprogram 186 -- name and is only relevant in CodePeer mode. It returns the entity 187 -- for the corresponding elaboration procedure for elaborating the body 188 -- of the referenced subprogram unit. This is used in the main generated 189 -- elaboration procedure by the binder in CodePeer mode only. 190 191 --------------- 192 -- Elab_Spec -- 193 --------------- 194 195 Attribute_Elab_Spec => True, 196 -- This attribute can only be applied to a program unit name. It 197 -- returns the entity for the corresponding elaboration procedure for 198 -- elaborating the spec of the referenced unit. This is used in the main 199 -- generated elaboration procedure by the binder, and is not normally 200 -- used in any other context, but there may be specialized situations in 201 -- which it is useful to be able to call this elaboration procedure from 202 -- Ada code, e.g. if it is necessary to do selective reelaboration to 203 -- fix some error. 204 205 ---------------- 206 -- Elaborated -- 207 ---------------- 208 209 Attribute_Elaborated => True, 210 -- Lunit'Elaborated, where Lunit is a library unit, yields a boolean 211 -- value indicating whether or not the body of the designated library 212 -- unit has been elaborated yet. 213 214 -------------- 215 -- Enum_Rep -- 216 -------------- 217 218 Attribute_Enum_Rep => True, 219 -- For every enumeration subtype S, S'Enum_Rep denotes a function 220 -- with the following specification: 221 -- 222 -- function S'Enum_Rep (Arg : S'Base) return universal_integer; 223 -- 224 -- The function returns the representation value for the given 225 -- enumeration value. This will be equal to the 'Pos value in the 226 -- absence of an enumeration representation clause. This is a static 227 -- attribute (i.e. the result is static if the argument is static). 228 229 -------------- 230 -- Enum_Val -- 231 -------------- 232 233 Attribute_Enum_Val => True, 234 -- For every enumeration subtype S, S'Enum_Val denotes a function with 235 -- the following specification: 236 -- 237 -- function S'Enum_Val (Arg : universal_integer) return S'Base; 238 -- 239 -- This function performs the inverse transformation to Enum_Rep. Given 240 -- a representation value for the type, it returns the corresponding 241 -- enumeration value. Constraint_Error is raised if no value of the 242 -- enumeration type corresponds to the given integer value. 243 244 ----------------- 245 -- Fixed_Value -- 246 ----------------- 247 248 Attribute_Fixed_Value => True, 249 -- For every fixed-point type S, S'Fixed_Value denotes a function 250 -- with the following specification: 251 -- 252 -- function S'Fixed_Value (Arg : universal_integer) return S; 253 -- 254 -- The value returned is the fixed-point value V such that 255 -- 256 -- V = Arg * S'Small 257 -- 258 -- The effect is thus equivalent to first converting the argument to 259 -- the integer type used to represent S, and then doing an unchecked 260 -- conversion to the fixed-point type. This attribute is primarily 261 -- intended for use in implementation of the input-output functions 262 -- for fixed-point values. 263 264 ----------------------- 265 -- Has_Discriminants -- 266 ----------------------- 267 268 Attribute_Has_Discriminants => True, 269 -- Gtyp'Has_Discriminants, where Gtyp is a generic formal type, yields 270 -- a Boolean value indicating whether or not the actual instantiation 271 -- type has discriminants. 272 273 --------- 274 -- Img -- 275 --------- 276 277 Attribute_Img => True, 278 -- The 'Img function is defined for any prefix, P, that denotes an 279 -- object of scalar type T. P'Img is equivalent to T'Image (P). This 280 -- is convenient for debugging. For example: 281 -- 282 -- Put_Line ("X = " & X'Img); 283 -- 284 -- has the same meaning as the more verbose: 285 -- 286 -- Put_Line ("X = " & Temperature_Type'Image (X)); 287 -- 288 -- where Temperature_Type is the subtype of the object X. 289 290 ------------------- 291 -- Integer_Value -- 292 ------------------- 293 294 Attribute_Integer_Value => True, 295 -- For every integer type S, S'Integer_Value denotes a function 296 -- with the following specification: 297 -- 298 -- function S'Integer_Value (Arg : universal_fixed) return S; 299 -- 300 -- The value returned is the integer value V, such that 301 -- 302 -- Arg = V * fixed-type'Small 303 -- 304 -- The effect is thus equivalent to first doing an unchecked convert 305 -- from the fixed-point type to its corresponding implementation type, 306 -- and then converting the result to the target integer type. This 307 -- attribute is primarily intended for use in implementation of the 308 -- standard input-output functions for fixed-point values. 309 310 Attribute_Invalid_Value => True, 311 -- For every scalar type, S'Invalid_Value designates an undefined value 312 -- of the type. If possible this value is an invalid value, and in fact 313 -- is identical to the value that would be set if Initialize_Scalars 314 -- mode were in effect (including the behavior of its value on 315 -- environment variables or binder switches). The intended use is to 316 -- set a value where initialization is required (e.g. as a result of the 317 -- coding standards in use), but logically no initialization is needed, 318 -- and the value should never be accessed. 319 320 Attribute_Loop_Entry => True, 321 -- For every object of a non-limited type, S'Loop_Entry [(Loop_Name)] 322 -- denotes the constant value of prefix S at the point of entry into the 323 -- related loop. The type of the attribute is the type of the prefix. 324 325 ------------------ 326 -- Machine_Size -- 327 ------------------ 328 329 Attribute_Machine_Size => True, 330 -- This attribute is identical to the Object_Size attribute. It is 331 -- provided for compatibility with the DEC attribute of this name. 332 333 ----------------------- 334 -- Maximum_Alignment -- 335 ----------------------- 336 337 Attribute_Maximum_Alignment => True, 338 -- Standard'Maximum_Alignment (Standard is the only permissible prefix) 339 -- provides the maximum useful alignment value for the target. This is a 340 -- static value that can be used to specify the alignment for an object, 341 -- guaranteeing that it is properly aligned in all cases. The time this 342 -- is useful is when an external object is imported and its alignment 343 -- requirements are unknown. This is a static attribute. 344 345 -------------------- 346 -- Mechanism_Code -- 347 -------------------- 348 349 Attribute_Mechanism_Code => True, 350 -- function'Mechanism_Code yields an integer code for the mechanism 351 -- used for the result of function, and subprogram'Mechanism_Code (n) 352 -- yields the mechanism used for formal parameter number n (a static 353 -- integer value, 1 = first parameter). The code returned is: 354 -- 355 -- 1 = by copy (value) 356 -- 2 = by reference 357 -- 3 = by descriptor (default descriptor type) 358 -- 4 = by descriptor (UBS unaligned bit string) 359 -- 5 = by descriptor (UBSB aligned bit string with arbitrary bounds) 360 -- 6 = by descriptor (UBA unaligned bit array) 361 -- 7 = by descriptor (S string, also scalar access type parameter) 362 -- 8 = by descriptor (SB string with arbitrary bounds) 363 -- 9 = by descriptor (A contiguous array) 364 -- 10 = by descriptor (NCA non-contiguous array) 365 366 -------------------- 367 -- Null_Parameter -- 368 -------------------- 369 370 Attribute_Null_Parameter => True, 371 -- A reference T'Null_Parameter denotes an (imaginary) object of type 372 -- or subtype T allocated at (machine) address zero. The attribute is 373 -- allowed only as the default expression of a formal parameter, or 374 -- as an actual expression of a subprogram call. In either case, the 375 -- subprogram must be imported. 376 -- 377 -- The identity of the object is represented by the address zero in 378 -- the argument list, independent of the passing mechanism (explicit 379 -- or default). 380 -- 381 -- The reason that this capability is needed is that for a record or 382 -- other composite object passed by reference, there is no other way 383 -- of specifying that a zero address should be passed. 384 385 ----------------- 386 -- Object_Size -- 387 ----------------- 388 389 Attribute_Object_Size => True, 390 -- Type'Object_Size is the same as Type'Size for all types except 391 -- fixed-point types and discrete types. For fixed-point types and 392 -- discrete types, this attribute gives the size used for default 393 -- allocation of objects and components of the size. See section in 394 -- Einfo ("Handling of type'Size values") for further details. 395 396 ------------------------- 397 -- Passed_By_Reference -- 398 ------------------------- 399 400 Attribute_Passed_By_Reference => True, 401 -- T'Passed_By_Reference for any subtype T returns a boolean value that 402 -- is true if the type is normally passed by reference and false if the 403 -- type is normally passed by copy in calls. For scalar types, the 404 -- result is always False and is static. For non-scalar types, the 405 -- result is non-static (since it is computed by Gigi). 406 407 ------------------ 408 -- Range_Length -- 409 ------------------ 410 411 Attribute_Range_Length => True, 412 -- T'Range_Length for any discrete type T yields the number of values 413 -- represented by the subtype (zero for a null range). The result is 414 -- static for static subtypes. Note that Range_Length applied to the 415 -- index subtype of a one dimensional array always gives the same result 416 -- as Range applied to the array itself. The result is of type universal 417 -- integer. 418 419 --------- 420 -- Ref -- 421 --------- 422 423 Attribute_Ref => True, 424 -- System.Address'Ref (Address is the only permissible prefix) is 425 -- equivalent to System'To_Address, provided for compatibility with 426 -- other compilers. 427 428 ------------------ 429 -- Storage_Unit -- 430 ------------------ 431 432 Attribute_Storage_Unit => True, 433 -- Standard'Storage_Unit (Standard is the only permissible prefix) 434 -- provides the value System.Storage_Unit, and is intended primarily 435 -- for constructing this definition in package System (see note above 436 -- in Default_Bit_Order description). The is a static attribute. 437 438 --------------- 439 -- Stub_Type -- 440 --------------- 441 442 Attribute_Stub_Type => True, 443 -- The GNAT implementation of remote access-to-classwide types is 444 -- organised as described in AARM E.4(20.t): a value of an RACW type 445 -- (designating a remote object) is represented as a normal access 446 -- value, pointing to a "stub" object which in turn contains the 447 -- necessary information to contact the designated remote object. A 448 -- call on any dispatching operation of such a stub object does the 449 -- remote call, if necessary, using the information in the stub object 450 -- to locate the target partition, etc. 451 -- 452 -- For a prefix T that denotes a remote access-to-classwide type, 453 -- T'Stub_Type denotes the type of the corresponding stub objects. 454 -- 455 -- By construction, the layout of T'Stub_Type is identical to that of 456 -- System.Partition_Interface.RACW_Stub_Type (see implementation notes 457 -- in body of Exp_Dist). 458 459 ----------------- 460 -- Target_Name -- 461 ----------------- 462 463 Attribute_Target_Name => True, 464 -- Standard'Target_Name yields the string identifying the target for the 465 -- compilation, taken from Sdefault.Target_Name. 466 467 ---------------- 468 -- To_Address -- 469 ---------------- 470 471 Attribute_To_Address => True, 472 -- System'To_Address (System is the only permissible prefix) is a 473 -- function that takes any integer value, and converts it into an 474 -- address value. The semantics is to first convert the integer value to 475 -- type Integer_Address according to normal conversion rules, and then 476 -- to convert this to an address using the same semantics as the 477 -- System.Storage_Elements.To_Address function. The important difference 478 -- is that this is a static attribute so it can be used in 479 -- initializations in preelaborate packages. 480 481 ---------------- 482 -- Type_Class -- 483 ---------------- 484 485 Attribute_Type_Class => True, 486 -- T'Type_Class for any type or subtype T yields the value of the type 487 -- class for the full type of T. If T is a generic formal type, then the 488 -- value is the value for the corresponding actual subtype. The value of 489 -- this attribute is of type System.Aux_DEC.Type_Class, which has the 490 -- following definition: 491 -- 492 -- type Type_Class is 493 -- (Type_Class_Enumeration, 494 -- Type_Class_Integer, 495 -- Type_Class_Fixed_Point, 496 -- Type_Class_Floating_Point, 497 -- Type_Class_Array, 498 -- Type_Class_Record, 499 -- Type_Class_Access, 500 -- Type_Class_Task, 501 -- Type_Class_Address); 502 -- 503 -- Protected types yield the value Type_Class_Task, which thus applies 504 -- to all concurrent types. This attribute is designed to be compatible 505 -- with the DEC Ada attribute of the same name. 506 -- 507 -- Note: if pragma Extend_System is used to merge the definitions of 508 -- Aux_DEC into System, then the type Type_Class can be referenced 509 -- as an entity within System, as can its enumeration literals. 510 511 ----------------- 512 -- UET_Address -- 513 ----------------- 514 515 Attribute_UET_Address => True, 516 -- Unit'UET_Address, where Unit is a program unit, yields the address 517 -- of the unit exception table for the specified unit. This is only 518 -- used in the internal implementation of exception handling. See the 519 -- implementation of unit Ada.Exceptions for details on its use. 520 521 ------------------------------ 522 -- Universal_Literal_String -- 523 ------------------------------ 524 525 Attribute_Universal_Literal_String => True, 526 -- The prefix of 'Universal_Literal_String must be a named number. 527 -- The static result is the string consisting of the characters of 528 -- the number as defined in the original source. This allows the 529 -- user program to access the actual text of named numbers without 530 -- intermediate conversions and without the need to enclose the 531 -- strings in quotes (which would preclude their use as numbers). 532 533 ------------------------- 534 -- Unrestricted_Access -- 535 ------------------------- 536 537 Attribute_Unrestricted_Access => True, 538 -- The Unrestricted_Access attribute is similar to Access except that 539 -- all accessibility and aliased view checks are omitted. This is very 540 -- much a user-beware attribute. Basically its status is very similar 541 -- to Address, for which it is a desirable replacement where the value 542 -- desired is an access type. In other words, its effect is identical 543 -- to first taking 'Address and then doing an unchecked conversion to 544 -- a desired access type. Note that in GNAT, but not necessarily in 545 -- other implementations, the use of static chains for inner level 546 -- subprograms means that Unrestricted_Access applied to a subprogram 547 -- yields a value that can be called as long as the subprogram is in 548 -- scope (normal Ada 95 accessibility rules restrict this usage). 549 550 --------------- 551 -- VADS_Size -- 552 --------------- 553 554 Attribute_VADS_Size => True, 555 -- Typ'VADS_Size yields the Size value typically yielded by some Ada 83 556 -- compilers. The differences between VADS_Size and Size is that for 557 -- scalar types for which no Size has been specified, VADS_Size yields 558 -- the Object_Size rather than the Value_Size. For example, while 559 -- Natural'Size is typically 31, the value of Natural'VADS_Size is 32. 560 -- For all other types, Size and VADS_Size yield the same value. 561 562 ------------------- 563 -- Valid_Scalars -- 564 ------------------- 565 566 Attribute_Valid_Scalars => True, 567 -- Obj'Valid_Scalars can be applied to any object. The result depends 568 -- on the type of the object: 569 -- 570 -- For a scalar type, the result is the same as obj'Valid 571 -- 572 -- For an array object, the result is True if the result of applying 573 -- Valid_Scalars to every component is True. For an empty array the 574 -- result is True. 575 -- 576 -- For a record object, the result is True if the result of applying 577 -- Valid_Scalars to every component is True. For class-wide types, 578 -- only the components of the base type are checked. For variant 579 -- records, only the components actually present are checked. The 580 -- discriminants, if any, are also checked. If there are no components 581 -- or discriminants, the result is True. 582 -- 583 -- For any other type that has discriminants, the result is True if 584 -- the result of applying Valid_Scalars to each discriminant is True. 585 -- 586 -- For all other types, the result is always True 587 -- 588 -- A warning is given for a trivially True result, when the attribute 589 -- is applied to an object that is not of scalar, array, or record 590 -- type, or in the composite case if no scalar subcomponents exist. For 591 -- a variant record, the warning is given only if none of the variants 592 -- have scalar subcomponents. In addition, the warning is suppressed 593 -- for private types, or generic formal types in an instance. 594 595 ---------------- 596 -- Value_Size -- 597 ---------------- 598 599 Attribute_Value_Size => True, 600 -- Type'Value_Size is the number of bits required to represent value of 601 -- the given subtype. It is the same as Type'Size, but, unlike Size, may 602 -- be set for non-first subtypes. See section in Einfo ("Handling of 603 -- type'Size values") for further details. 604 605 --------------- 606 -- Word_Size -- 607 --------------- 608 609 Attribute_Word_Size => True, 610 -- Standard'Word_Size (Standard is the only permissible prefix) 611 -- provides the value System.Word_Size, and is intended primarily 612 -- for constructing this definition in package System (see note above 613 -- in Default_Bit_Order description). This is a static attribute. 614 615 others => False); 616 617 ----------------- 618 -- Subprograms -- 619 ----------------- 620 621 procedure Analyze_Attribute (N : Node_Id); 622 -- Performs bottom up semantic analysis of an attribute. Note that the 623 -- parser has already checked that type returning attributes appear only 624 -- in appropriate contexts (i.e. in subtype marks, or as prefixes for 625 -- other attributes). 626 627 function Name_Implies_Lvalue_Prefix (Nam : Name_Id) return Boolean; 628 -- Determine whether the name of an attribute reference categorizes its 629 -- prefix as an lvalue. The following attributes fall under this bracket 630 -- by directly or indirectly modifying their prefixes. 631 -- Access 632 -- Address 633 -- Input 634 -- Read 635 -- Unchecked_Access 636 -- Unrestricted_Access 637 638 procedure Resolve_Attribute (N : Node_Id; Typ : Entity_Id); 639 -- Performs type resolution of attribute. If the attribute yields a 640 -- universal value, mark its type as that of the context. On the other 641 -- hand, if the context itself is universal (as in T'Val (T'Pos (X)), mark 642 -- the type as being the largest type of that class that can be used at 643 -- run-time. This is correct since either the value gets folded (in which 644 -- case it doesn't matter what type of the class we give if, since the 645 -- folding uses universal arithmetic anyway) or it doesn't get folded (in 646 -- which case it is going to be dealt with at runtime, and the largest type 647 -- is right). 648 649 function Stream_Attribute_Available 650 (Typ : Entity_Id; 651 Nam : TSS_Name_Type; 652 Partial_View : Entity_Id := Empty) return Boolean; 653 -- For a limited type Typ, return True if and only if the given attribute 654 -- is available. For Ada 2005, availability is defined by 13.13.2(36/1). 655 -- For Ada 95, an attribute is considered to be available if it has been 656 -- specified using an attribute definition clause for the type, or for its 657 -- full view, or for an ancestor of either. Parameter Partial_View is used 658 -- only internally, when checking for an attribute definition clause that 659 -- is not visible (Ada 95 only). 660 661end Sem_Attr; 662