1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S E M _ A U X -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2013, 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. 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 COPYING3. If not, go to -- 19-- http://www.gnu.org/licenses for a complete copy of the license. -- 20-- -- 21-- As a special exception, if other files instantiate generics from this -- 22-- unit, or you link this unit with other files to produce an executable, -- 23-- this unit does not by itself cause the resulting executable to be -- 24-- covered by the GNU General Public License. This exception does not -- 25-- however invalidate any other reasons why the executable file might be -- 26-- 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-- Package containing utility procedures used throughout the compiler, 34-- and also by ASIS so dependencies are limited to ASIS included packages. 35 36-- Historical note. Many of the routines here were originally in Einfo, but 37-- Einfo is supposed to be a relatively low level package dealing with the 38-- content of entities in the tree, so this package is used for routines that 39-- require more than minimal semantic knowledge. 40 41with Alloc; use Alloc; 42with Namet; use Namet; 43with Table; 44with Types; use Types; 45 46package Sem_Aux is 47 48 -------------------------------- 49 -- Obsolescent Warnings Table -- 50 -------------------------------- 51 52 -- This table records entities for which a pragma Obsolescent with a 53 -- message argument has been processed. 54 55 type OWT_Record is record 56 Ent : Entity_Id; 57 -- The entity to which the pragma applies 58 59 Msg : String_Id; 60 -- The string containing the message 61 end record; 62 63 package Obsolescent_Warnings is new Table.Table ( 64 Table_Component_Type => OWT_Record, 65 Table_Index_Type => Int, 66 Table_Low_Bound => 0, 67 Table_Initial => Alloc.Obsolescent_Warnings_Initial, 68 Table_Increment => Alloc.Obsolescent_Warnings_Increment, 69 Table_Name => "Obsolescent_Warnings"); 70 71 procedure Initialize; 72 -- Called at the start of compilation of each new main source file to 73 -- initialize the allocation of the Obsolescent_Warnings table. Note that 74 -- Initialize must not be called if Tree_Read is used. 75 76 procedure Tree_Read; 77 -- Initializes Obsolescent_Warnings table from current tree file using the 78 -- relevant Table.Tree_Read routine. 79 80 procedure Tree_Write; 81 -- Writes out Obsolescent_Warnings table to current tree file using the 82 -- relevant Table.Tree_Write routine. 83 84 ----------------- 85 -- Subprograms -- 86 ----------------- 87 88 function Ancestor_Subtype (Typ : Entity_Id) return Entity_Id; 89 -- The argument Id is a type or subtype entity. If the argument is a 90 -- subtype then it returns the subtype or type from which the subtype was 91 -- obtained, otherwise it returns Empty. 92 93 function Available_View (Ent : Entity_Id) return Entity_Id; 94 -- Ent denotes an abstract state or a type that may come from a limited 95 -- with clause. Return the non-limited view of Ent if there is one or Ent 96 -- if this is not the case. 97 98 function Constant_Value (Ent : Entity_Id) return Node_Id; 99 -- Ent is a variable, constant, named integer, or named real entity. This 100 -- call obtains the initialization expression for the entity. Will return 101 -- Empty for a deferred constant whose full view is not available or 102 -- in some other cases of internal entities, which cannot be treated as 103 -- constants from the point of view of constant folding. Empty is also 104 -- returned for variables with no initialization expression. 105 106 function Corresponding_Unsigned_Type (Typ : Entity_Id) return Entity_Id; 107 -- Typ is a signed integer subtype. This routine returns the standard 108 -- unsigned type with the same Esize as the implementation base type of 109 -- Typ, e.g. Long_Integer => Long_Unsigned. 110 111 function Enclosing_Dynamic_Scope (Ent : Entity_Id) return Entity_Id; 112 -- For any entity, Ent, returns the closest dynamic scope in which the 113 -- entity is declared or Standard_Standard for library-level entities. 114 115 function First_Discriminant (Typ : Entity_Id) return Entity_Id; 116 -- Typ is a type with discriminants. The discriminants are the first 117 -- entities declared in the type, so normally this is equivalent to 118 -- First_Entity. The exception arises for tagged types, where the tag 119 -- itself is prepended to the front of the entity chain, so the 120 -- First_Discriminant function steps past the tag if it is present. 121 122 function First_Stored_Discriminant (Typ : Entity_Id) return Entity_Id; 123 -- Typ is a type with discriminants. Gives the first discriminant stored 124 -- in an object of this type. In many cases, these are the same as the 125 -- normal visible discriminants for the type, but in the case of renamed 126 -- discriminants, this is not always the case. 127 -- 128 -- For tagged types, and untagged types which are root types or derived 129 -- types but which do not rename discriminants in their root type, the 130 -- stored discriminants are the same as the actual discriminants of the 131 -- type, and hence this function is the same as First_Discriminant. 132 -- 133 -- For derived non-tagged types that rename discriminants in the root type 134 -- this is the first of the discriminants that occur in the root type. To 135 -- be precise, in this case stored discriminants are entities attached to 136 -- the entity chain of the derived type which are a copy of the 137 -- discriminants of the root type. Furthermore their Is_Completely_Hidden 138 -- flag is set since although they are actually stored in the object, they 139 -- are not in the set of discriminants that is visible in the type. 140 -- 141 -- For derived untagged types, the set of stored discriminants are the real 142 -- discriminants from Gigi's standpoint, i.e. those that will be stored in 143 -- actual objects of the type. 144 145 function First_Subtype (Typ : Entity_Id) return Entity_Id; 146 -- Applies to all types and subtypes. For types, yields the first subtype 147 -- of the type. For subtypes, yields the first subtype of the base type of 148 -- the subtype. 149 150 function First_Tag_Component (Typ : Entity_Id) return Entity_Id; 151 -- Typ must be a tagged record type. This function returns the Entity for 152 -- the first _Tag field in the record type. 153 154 function Get_Rep_Item 155 (E : Entity_Id; 156 Nam : Name_Id; 157 Check_Parents : Boolean := True) return Node_Id; 158 -- Searches the Rep_Item chain for a given entity E, for an instance of a 159 -- rep item (pragma, attribute definition clause, or aspect specification) 160 -- whose name matches the given name Nam. If Check_Parents is False then it 161 -- only returns rep item that has been directly specified for E (and not 162 -- inherited from its parents, if any). If one is found, it is returned, 163 -- otherwise Empty is returned. A special case is that when Nam is 164 -- Name_Priority, the call will also find Interrupt_Priority. 165 166 function Get_Rep_Item 167 (E : Entity_Id; 168 Nam1 : Name_Id; 169 Nam2 : Name_Id; 170 Check_Parents : Boolean := True) return Node_Id; 171 -- Searches the Rep_Item chain for a given entity E, for an instance of a 172 -- rep item (pragma, attribute definition clause, or aspect specification) 173 -- whose name matches one of the given names Nam1 or Nam2. If Check_Parents 174 -- is False then it only returns rep item that has been directly specified 175 -- for E (and not inherited from its parents, if any). If one is found, it 176 -- is returned, otherwise Empty is returned. A special case is that when 177 -- one of the given names is Name_Priority, the call will also find 178 -- Interrupt_Priority. 179 180 function Get_Rep_Pragma 181 (E : Entity_Id; 182 Nam : Name_Id; 183 Check_Parents : Boolean := True) return Node_Id; 184 -- Searches the Rep_Item chain for a given entity E, for an instance of a 185 -- representation pragma whose name matches the given name Nam. If 186 -- Check_Parents is False then it only returns representation pragma that 187 -- has been directly specified for E (and not inherited from its parents, 188 -- if any). If one is found and if it is the first rep item in the list 189 -- that matches Nam, it is returned, otherwise Empty is returned. A special 190 -- case is that when Nam is Name_Priority, the call will also find 191 -- Interrupt_Priority. 192 193 function Get_Rep_Pragma 194 (E : Entity_Id; 195 Nam1 : Name_Id; 196 Nam2 : Name_Id; 197 Check_Parents : Boolean := True) return Node_Id; 198 -- Searches the Rep_Item chain for a given entity E, for an instance of a 199 -- representation pragma whose name matches one of the given names Nam1 or 200 -- Nam2. If Check_Parents is False then it only returns representation 201 -- pragma that has been directly specified for E (and not inherited from 202 -- its parents, if any). If one is found and if it is the first rep item in 203 -- the list that matches one of the given names, it is returned, otherwise 204 -- Empty is returned. A special case is that when one of the given names is 205 -- Name_Priority, the call will also find Interrupt_Priority. 206 207 function Has_Rep_Item 208 (E : Entity_Id; 209 Nam : Name_Id; 210 Check_Parents : Boolean := True) return Boolean; 211 -- Searches the Rep_Item chain for the given entity E, for an instance of a 212 -- rep item (pragma, attribute definition clause, or aspect specification) 213 -- with the given name Nam. If Check_Parents is False then it only checks 214 -- for a rep item that has been directly specified for E (and not inherited 215 -- from its parents, if any). If found then True is returned, otherwise 216 -- False indicates that no matching entry was found. 217 218 function Has_Rep_Item 219 (E : Entity_Id; 220 Nam1 : Name_Id; 221 Nam2 : Name_Id; 222 Check_Parents : Boolean := True) return Boolean; 223 -- Searches the Rep_Item chain for the given entity E, for an instance of a 224 -- rep item (pragma, attribute definition clause, or aspect specification) 225 -- with the given names Nam1 or Nam2. If Check_Parents is False then it 226 -- only checks for a rep item that has been directly specified for E (and 227 -- not inherited from its parents, if any). If found then True is returned, 228 -- otherwise False indicates that no matching entry was found. 229 230 function Has_Rep_Pragma 231 (E : Entity_Id; 232 Nam : Name_Id; 233 Check_Parents : Boolean := True) return Boolean; 234 -- Searches the Rep_Item chain for the given entity E, for an instance of a 235 -- representation pragma with the given name Nam. If Check_Parents is False 236 -- then it only checks for a representation pragma that has been directly 237 -- specified for E (and not inherited from its parents, if any). If found 238 -- and if it is the first rep item in the list that matches Nam then True 239 -- is returned, otherwise False indicates that no matching entry was found. 240 241 function Has_Rep_Pragma 242 (E : Entity_Id; 243 Nam1 : Name_Id; 244 Nam2 : Name_Id; 245 Check_Parents : Boolean := True) return Boolean; 246 -- Searches the Rep_Item chain for the given entity E, for an instance of a 247 -- representation pragma with the given names Nam1 or Nam2. If 248 -- Check_Parents is False then it only checks for a rep item that has been 249 -- directly specified for E (and not inherited from its parents, if any). 250 -- If found and if it is the first rep item in the list that matches one of 251 -- the given names then True is returned, otherwise False indicates that no 252 -- matching entry was found. 253 254 function Has_Unconstrained_Elements (T : Entity_Id) return Boolean; 255 -- True if T has discriminants and is unconstrained, or is an array type 256 -- whose element type Has_Unconstrained_Elements. 257 258 function In_Generic_Body (Id : Entity_Id) return Boolean; 259 -- Determine whether entity Id appears inside a generic body 260 261 function Initialization_Suppressed (Typ : Entity_Id) return Boolean; 262 pragma Inline (Initialization_Suppressed); 263 -- Returns True if initialization should be suppressed for the given type 264 -- or subtype. This is true if Suppress_Initialization is set either for 265 -- the subtype itself, or for the corresponding base type. 266 267 function Is_Body (N : Node_Id) return Boolean; 268 -- Determine whether an arbitrary node denotes a body 269 270 function Is_By_Copy_Type (Ent : Entity_Id) return Boolean; 271 -- Ent is any entity. Returns True if Ent is a type entity where the type 272 -- is required to be passed by copy, as defined in (RM 6.2(3)). 273 274 function Is_By_Reference_Type (Ent : Entity_Id) return Boolean; 275 -- Ent is any entity. Returns True if Ent is a type entity where the type 276 -- is required to be passed by reference, as defined in (RM 6.2(4-9)). 277 278 function Is_Derived_Type (Ent : Entity_Id) return Boolean; 279 -- Determines if the given entity Ent is a derived type. Result is always 280 -- false if argument is not a type. 281 282 function Is_Generic_Formal (E : Entity_Id) return Boolean; 283 -- Determine whether E is a generic formal parameter. In particular this is 284 -- used to set the visibility of generic formals of a generic package 285 -- declared with a box or with partial parameterization. 286 287 function Is_Indefinite_Subtype (Ent : Entity_Id) return Boolean; 288 -- Ent is any entity. Determines if given entity is an unconstrained array 289 -- type or subtype, a discriminated record type or subtype with no initial 290 -- discriminant values or a class wide type or subtype and returns True if 291 -- so. False for other type entities, or any entities that are not types. 292 293 function Is_Immutably_Limited_Type (Ent : Entity_Id) return Boolean; 294 -- Implements definition in Ada 2012 RM-7.5 (8.1/3). This differs from the 295 -- following predicate in that an untagged record with immutably limited 296 -- components is NOT by itself immutably limited. This matters, e.g. when 297 -- checking the legality of an access to the current instance. 298 299 function Is_Limited_View (Ent : Entity_Id) return Boolean; 300 -- Ent is any entity. True for a type that is "inherently" limited (i.e. 301 -- cannot become nonlimited). From the Ada 2005 RM-7.5(8.1/2), "a type with 302 -- a part that is of a task, protected, or explicitly limited record type". 303 -- These are the types that are defined as return-by-reference types in Ada 304 -- 95 (see RM95-6.5(11-16)). In Ada 2005, these are the types that require 305 -- build-in-place for function calls. Note that build-in-place is allowed 306 -- for other types, too. This is also used for identifying pure procedures 307 -- whose calls should not be eliminated (RM 10.2.1(18/2)). 308 309 function Is_Limited_Type (Ent : Entity_Id) return Boolean; 310 -- Ent is any entity. Returns true if Ent is a limited type (limited 311 -- private type, limited interface type, task type, protected type, 312 -- composite containing a limited component, or a subtype of any of 313 -- these types). This older routine overlaps with the previous one, this 314 -- should be cleaned up??? 315 316 function Nearest_Ancestor (Typ : Entity_Id) return Entity_Id; 317 -- Given a subtype Typ, this function finds out the nearest ancestor from 318 -- which constraints and predicates are inherited. There is no simple link 319 -- for doing this, consider: 320 -- 321 -- subtype R is Integer range 1 .. 10; 322 -- type T is new R; 323 -- 324 -- In this case the nearest ancestor is R, but the Etype of T'Base will 325 -- point to R'Base, so we have to go rummaging in the declarations to get 326 -- this information. It is used for making sure we freeze this before we 327 -- freeze Typ, and also for retrieving inherited predicate information. 328 -- For the case of base types or first subtypes, there is no useful entity 329 -- to return, so Empty is returned. 330 -- 331 -- Note: this is similar to Ancestor_Subtype except that it also deals 332 -- with the case of derived types. 333 334 function Nearest_Dynamic_Scope (Ent : Entity_Id) return Entity_Id; 335 -- This is similar to Enclosing_Dynamic_Scope except that if Ent is itself 336 -- a dynamic scope, then it is returned. Otherwise the result is the same 337 -- as that returned by Enclosing_Dynamic_Scope. 338 339 function Next_Tag_Component (Tag : Entity_Id) return Entity_Id; 340 -- Tag must be an entity representing a _Tag field of a tagged record. 341 -- The result returned is the next _Tag field in this record, or Empty 342 -- if this is the last such field. 343 344 function Number_Discriminants (Typ : Entity_Id) return Pos; 345 -- Typ is a type with discriminants, yields number of discriminants in type 346 347 function Object_Type_Has_Constrained_Partial_View 348 (Typ : Entity_Id; 349 Scop : Entity_Id) return Boolean; 350 -- Return True if type of object has attribute Has_Constrained_Partial_View 351 -- set to True; in addition, within a generic body, return True if subtype 352 -- of the object is a descendant of an untagged generic formal private or 353 -- derived type, and the subtype is not an unconstrained array subtype 354 -- (RM 3.3(23.10/3)). 355 356 function Ultimate_Alias (Prim : Entity_Id) return Entity_Id; 357 pragma Inline (Ultimate_Alias); 358 -- Return the last entity in the chain of aliased entities of Prim. If Prim 359 -- has no alias return Prim. 360 361 function Unit_Declaration_Node (Unit_Id : Entity_Id) return Node_Id; 362 -- Unit_Id is the simple name of a program unit, this function returns the 363 -- corresponding xxx_Declaration node for the entity. Also applies to the 364 -- body entities for subprograms, tasks and protected units, in which case 365 -- it returns the subprogram, task or protected body node for it. The unit 366 -- may be a child unit with any number of ancestors. 367 368 function Package_Specification (Pack_Id : Entity_Id) return Node_Id; 369 -- Given an entity for a package or generic package, return corresponding 370 -- package specification. Simplifies handling of child units, and better 371 -- than the old idiom: Specification (Unit_Declaration_Node (Pack_Id)). 372end Sem_Aux; 373