1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
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. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 -- Package containing utility procedures used throughout the semantics
29 with Einfo; use Einfo;
30 with Types; use Types;
31 with Uintp; use Uintp;
32 with Urealp; use Urealp;
36 function Abstract_Interface_List (Typ : Entity_Id) return List_Id;
37 -- Given a type that implements interfaces look for its associated
38 -- definition node and return its list of interfaces.
40 procedure Add_Access_Type_To_Process (E : Entity_Id; A : Entity_Id);
41 -- Add A to the list of access types to process when expanding the
44 function Alignment_In_Bits (E : Entity_Id) return Uint;
45 -- If the alignment of the type or object E is currently known to the
46 -- compiler, then this function returns the alignment value in bits.
47 -- Otherwise Uint_0 is returned, indicating that the alignment of the
48 -- entity is not yet known to the compiler.
50 procedure Apply_Compile_Time_Constraint_Error
53 Reason : RT_Exception_Code;
54 Ent : Entity_Id := Empty;
55 Typ : Entity_Id := Empty;
56 Loc : Source_Ptr := No_Location;
57 Rep : Boolean := True;
58 Warn : Boolean := False);
59 -- N is a subexpression which will raise constraint error when evaluated
60 -- at runtime. Msg is a message that explains the reason for raising the
61 -- exception. The last character is ? if the message is always a warning,
62 -- even in Ada 95, and is not a ? if the message represents an illegality
63 -- (because of violation of static expression rules) in Ada 95 (but not
64 -- in Ada 83). Typically this routine posts all messages at the Sloc of
65 -- node N. However, if Loc /= No_Location, Loc is the Sloc used to output
66 -- the message. After posting the appropriate message, and if the flag
67 -- Rep is set, this routine replaces the expression with an appropriate
68 -- N_Raise_Constraint_Error node using the given Reason code. This node
69 -- is then marked as being static if the original node is static, but
70 -- sets the flag Raises_Constraint_Error, preventing further evaluation.
71 -- The error message may contain a } or & insertion character. This
72 -- normally references Etype (N), unless the Ent argument is given
73 -- explicitly, in which case it is used instead. The type of the raise
74 -- node that is built is normally Etype (N), but if the Typ parameter
75 -- is present, this is used instead. Warn is normally False. If it is
76 -- True then the message is treated as a warning even though it does
77 -- not end with a ? (this is used when the caller wants to parametrize
78 -- whether an error or warning is given.
80 function Build_Actual_Subtype
82 N : Node_Or_Entity_Id) return Node_Id;
83 -- Build an anonymous subtype for an entity or expression, using the
84 -- bounds of the entity or the discriminants of the enclosing record.
85 -- T is the type for which the actual subtype is required, and N is either
86 -- a defining identifier, or any subexpression.
88 function Build_Actual_Subtype_Of_Component
90 N : Node_Id) return Node_Id;
91 -- Determine whether a selected component has a type that depends on
92 -- discriminants, and build actual subtype for it if so.
94 function Build_Default_Subtype
96 N : Node_Id) return Entity_Id;
97 -- If T is an unconstrained type with defaulted discriminants, build a
98 -- subtype constrained by the default values, insert the subtype
99 -- declaration in the tree before N, and return the entity of that
100 -- subtype. Otherwise, simply return T.
102 function Build_Discriminal_Subtype_Of_Component
103 (T : Entity_Id) return Node_Id;
104 -- Determine whether a record component has a type that depends on
105 -- discriminants, and build actual subtype for it if so.
107 procedure Build_Elaboration_Entity (N : Node_Id; Spec_Id : Entity_Id);
108 -- Given a compilation unit node N, allocate an elaboration boolean for
109 -- the compilation unit, and install it in the Elaboration_Entity field
110 -- of Spec_Id, the entity for the compilation unit.
112 function Cannot_Raise_Constraint_Error (Expr : Node_Id) return Boolean;
113 -- Returns True if the expression cannot possibly raise Constraint_Error.
114 -- The response is conservative in the sense that a result of False does
115 -- not necessarily mean that CE could be raised, but a response of True
116 -- means that for sure CE cannot be raised.
118 procedure Check_Fully_Declared (T : Entity_Id; N : Node_Id);
119 -- Verify that the full declaration of type T has been seen. If not,
120 -- place error message on node N. Used in object declarations, type
121 -- conversions, qualified expressions.
123 procedure Check_Potentially_Blocking_Operation (N : Node_Id);
124 -- N is one of the statement forms that is a potentially blocking
125 -- operation. If it appears within a protected action, emit warning.
127 procedure Check_VMS (Construct : Node_Id);
128 -- Check that this the target is OpenVMS, and if so, return with
129 -- no effect, otherwise post an error noting this can only be used
130 -- with OpenVMS ports. The argument is the construct in question
131 -- and is used to post the error message.
133 procedure Collect_Abstract_Interfaces
135 Ifaces_List : out Elist_Id;
136 Exclude_Parent_Interfaces : Boolean := False);
137 -- Ada 2005 (AI-251): Collect whole list of abstract interfaces that are
138 -- directly or indirectly implemented by T. Exclude_Parent_Interfaces is
139 -- used to avoid addition of inherited interfaces to the generated list.
141 function Collect_Primitive_Operations (T : Entity_Id) return Elist_Id;
142 -- Called upon type derivation and extension. We scan the declarative
143 -- part in which the type appears, and collect subprograms that have
144 -- one subsidiary subtype of the type. These subprograms can only
145 -- appear after the type itself.
147 function Compile_Time_Constraint_Error
150 Ent : Entity_Id := Empty;
151 Loc : Source_Ptr := No_Location;
152 Warn : Boolean := False) return Node_Id;
153 -- This is similar to Apply_Compile_Time_Constraint_Error in that it
154 -- generates a warning (or error) message in the same manner, but it does
155 -- not replace any nodes. For convenience, the function always returns its
156 -- first argument. The message is a warning if the message ends with ?, or
157 -- we are operating in Ada 83 mode, or if the Warn parameter is set to
160 procedure Conditional_Delay (New_Ent, Old_Ent : Entity_Id);
161 -- Sets the Has_Delayed_Freeze flag of New if the Delayed_Freeze flag
162 -- of Old is set and Old has no yet been Frozen (i.e. Is_Frozen is false);
164 function Current_Entity (N : Node_Id) return Entity_Id;
165 -- Find the currently visible definition for a given identifier, that is to
166 -- say the first entry in the visibility chain for the Chars of N.
168 function Current_Entity_In_Scope (N : Node_Id) return Entity_Id;
169 -- Find whether there is a previous definition for identifier N in the
170 -- current scope. Because declarations for a scope are not necessarily
171 -- contiguous (e.g. for packages) the first entry on the visibility chain
172 -- for N is not necessarily in the current scope.
174 function Current_Scope return Entity_Id;
175 -- Get entity representing current scope
177 function Current_Subprogram return Entity_Id;
178 -- Returns current enclosing subprogram. If Current_Scope is a subprogram,
179 -- then that is what is returned, otherwise the Enclosing_Subprogram of
180 -- the Current_Scope is returned. The returned value is Empty if this
181 -- is called from a library package which is not within any subprogram.
183 function Defining_Entity (N : Node_Id) return Entity_Id;
184 -- Given a declaration N, returns the associated defining entity. If
185 -- the declaration has a specification, the entity is obtained from
186 -- the specification. If the declaration has a defining unit name,
187 -- then the defining entity is obtained from the defining unit name
188 -- ignoring any child unit prefixes.
190 function Denotes_Discriminant
192 Check_Concurrent : Boolean := False) return Boolean;
193 -- Returns True if node N is an Entity_Name node for a discriminant.
194 -- If the flag Check_Concurrent is true, function also returns true
195 -- when N denotes the discriminal of the discriminant of a concurrent
196 -- type. This is necessary to disable some optimizations on private
197 -- components of protected types, and constraint checks on entry
198 -- families constrained by discriminants.
200 function Depends_On_Discriminant (N : Node_Id) return Boolean;
201 -- Returns True if N denotes a discriminant or if N is a range, a subtype
202 -- indication or a scalar subtype where one of the bounds is a
205 function Designate_Same_Unit
207 Name2 : Node_Id) return Boolean;
208 -- Return true if Name1 and Name2 designate the same unit name;
209 -- each of these names is supposed to be a selected component name,
210 -- an expanded name, a defining program unit name or an identifier
212 function Enclosing_Generic_Body
213 (N : Node_Id) return Node_Id;
214 -- Returns the Node_Id associated with the innermost enclosing
215 -- generic body, if any. If none, then returns Empty.
217 function Enclosing_Generic_Unit
218 (N : Node_Id) return Node_Id;
219 -- Returns the Node_Id associated with the innermost enclosing
220 -- generic unit, if any. If none, then returns Empty.
222 function Enclosing_Lib_Unit_Entity return Entity_Id;
223 -- Returns the entity of enclosing N_Compilation_Unit Node which is the
224 -- root of the current scope (which must not be Standard_Standard, and
225 -- the caller is responsible for ensuring this condition).
227 function Enclosing_Lib_Unit_Node (N : Node_Id) return Node_Id;
228 -- Returns the enclosing N_Compilation_Unit Node that is the root
229 -- of a subtree containing N.
231 function Enclosing_Subprogram (E : Entity_Id) return Entity_Id;
232 -- Utility function to return the Ada entity of the subprogram enclosing
233 -- the entity E, if any. Returns Empty if no enclosing subprogram.
235 procedure Ensure_Freeze_Node (E : Entity_Id);
236 -- Make sure a freeze node is allocated for entity E. If necessary,
237 -- build and initialize a new freeze node and set Has_Delayed_Freeze
238 -- true for entity E.
240 procedure Enter_Name (Def_Id : Entity_Id);
241 -- Insert new name in symbol table of current scope with check for
242 -- duplications (error message is issued if a conflict is found)
243 -- Note: Enter_Name is not used for overloadable entities, instead
244 -- these are entered using Sem_Ch6.Enter_Overloadable_Entity.
246 procedure Explain_Limited_Type (T : Entity_Id; N : Node_Id);
247 -- This procedure is called after issuing a message complaining
248 -- about an inappropriate use of limited type T. If useful, it
249 -- adds additional continuation lines to the message explaining
250 -- why type T is limited. Messages are placed at node N.
252 function Find_Corresponding_Discriminant
254 Typ : Entity_Id) return Entity_Id;
255 -- Because discriminants may have different names in a generic unit
256 -- and in an instance, they are resolved positionally when possible.
257 -- A reference to a discriminant carries the discriminant that it
258 -- denotes when analyzed. Subsequent uses of this id on a different
259 -- type denote the discriminant at the same position in this new type.
261 function First_Actual (Node : Node_Id) return Node_Id;
262 -- Node is an N_Function_Call or N_Procedure_Call_Statement node. The
263 -- result returned is the first actual parameter in declaration order
264 -- (not the order of parameters as they appeared in the source, which
265 -- can be quite different as a result of the use of named parameters).
266 -- Empty is returned for a call with no parameters. The procedure for
267 -- iterating through the actuals in declaration order is to use this
268 -- function to find the first actual, and then use Next_Actual to obtain
269 -- the next actual in declaration order. Note that the value returned
270 -- is always the expression (not the N_Parameter_Association nodes
271 -- even if named association is used).
273 function Full_Qualified_Name (E : Entity_Id) return String_Id;
274 -- Generates the string literal corresponding to the E's full qualified
275 -- name in upper case. An ASCII.NUL is appended as the last character.
276 -- The names in the string are generated by Namet.Get_Decoded_Name_String.
278 function Find_Static_Alternative (N : Node_Id) return Node_Id;
279 -- N is a case statement whose expression is a compile-time value.
280 -- Determine the alternative chosen, so that the code of non-selected
281 -- alternatives, and the warnings that may apply to them, are removed.
283 procedure Gather_Components
286 Governed_By : List_Id;
288 Report_Errors : out Boolean);
289 -- The purpose of this procedure is to gather the valid components in a
290 -- record type according to the values of its discriminants, in order to
291 -- validate the components of a record aggregate.
293 -- Typ is the type of the aggregate when its constrained discriminants
294 -- need to be collected, otherwise it is Empty.
296 -- Comp_List is an N_Component_List node.
298 -- Governed_By is a list of N_Component_Association nodes, where each
299 -- choice list contains the name of a discriminant and the expression
300 -- field gives its value. The values of the discriminants governing
301 -- the (possibly nested) variant parts in Comp_List are found in this
302 -- Component_Association List.
304 -- Into is the list where the valid components are appended. Note that
305 -- Into need not be an Empty list. If it's not, components are attached
308 -- Report_Errors is set to True if the values of the discriminants are
311 -- This procedure is also used when building a record subtype. If the
312 -- discriminant constraint of the subtype is static, the components of the
313 -- subtype are only those of the variants selected by the values of the
314 -- discriminants. Otherwise all components of the parent must be included
315 -- in the subtype for semantic analysis.
317 function Get_Actual_Subtype (N : Node_Id) return Entity_Id;
318 -- Given a node for an expression, obtain the actual subtype of the
319 -- expression. In the case of a parameter where the formal is an
320 -- unconstrained array or discriminated type, this will be the
321 -- previously constructed subtype of the actual. Note that this is
322 -- not quite the "Actual Subtype" of the RM, since it is always
323 -- a constrained type, i.e. it is the subtype of the value of the
324 -- actual. The actual subtype is also returned in other cases where
325 -- it has already been constructed for an object. Otherwise the
326 -- expression type is returned unchanged, except for the case of an
327 -- unconstrained array type, where an actual subtype is created, using
328 -- Insert_Actions if necessary to insert any associated actions.
330 function Get_Actual_Subtype_If_Available (N : Node_Id) return Entity_Id;
331 -- This is like Get_Actual_Subtype, except that it never constructs an
332 -- actual subtype. If an actual subtype is already available, i.e. the
333 -- Actual_Subtype field of the corresponding entity is set, then it is
334 -- returned. Otherwise the Etype of the node is returned.
336 function Get_Default_External_Name (E : Node_Or_Entity_Id) return Node_Id;
337 -- This is used to construct the string literal node representing a
338 -- default external name, i.e. one that is constructed from the name
339 -- of an entity, or (in the case of extended DEC import/export pragmas,
340 -- an identifier provided as the external name. Letters in the name are
341 -- according to the setting of Opt.External_Name_Default_Casing.
343 function Get_Generic_Entity (N : Node_Id) return Entity_Id;
344 -- Returns the true generic entity in an instantiation. If the name in
345 -- the instantiation is a renaming, the function returns the renamed
348 procedure Get_Index_Bounds (N : Node_Id; L, H : out Node_Id);
349 -- This procedure assigns to L and H respectively the values of the
350 -- low and high bounds of node N, which must be a range, subtype
351 -- indication, or the name of a scalar subtype. The result in L, H
352 -- may be set to Error if there was an earlier error in the range.
354 function Get_Enum_Lit_From_Pos
357 Loc : Source_Ptr) return Entity_Id;
358 -- This function obtains the E_Enumeration_Literal entity for the
359 -- specified value from the enumneration type or subtype T. The
360 -- second argument is the Pos value, which is assumed to be in range.
361 -- The third argument supplies a source location for constructed
362 -- nodes returned by this function.
364 procedure Get_Library_Unit_Name_String (Decl_Node : Node_Id);
365 -- Retrieve the fully expanded name of the library unit declared by
366 -- Decl_Node into the name buffer.
368 function Get_Name_Entity_Id (Id : Name_Id) return Entity_Id;
369 -- An entity value is associated with each name in the name table. The
370 -- Get_Name_Entity_Id function fetches the Entity_Id of this entity,
371 -- which is the innermost visible entity with the given name. See the
372 -- body of Sem_Ch8 for further details on handling of entity visibility.
374 function Get_Subprogram_Entity (Nod : Node_Id) return Entity_Id;
375 -- Nod is either a procedure call statement, or a function call, or
376 -- an accept statement node. This procedure finds the Entity_Id of the
377 -- related subprogram or entry and returns it, or if no subprogram can
378 -- be found, returns Empty.
380 function Get_Referenced_Object (N : Node_Id) return Node_Id;
381 -- Given a node, return the renamed object if the node represents
382 -- a renamed object, otherwise return the node unchanged. The node
383 -- may represent an arbitrary expression.
385 function Get_Subprogram_Body (E : Entity_Id) return Node_Id;
386 -- Given the entity for a subprogram (E_Function or E_Procedure),
387 -- return the corresponding N_Subprogram_Body node. If the corresponding
388 -- body of the declaration is missing (as for an imported subprogram)
391 function Get_Task_Body_Procedure (E : Entity_Id) return Node_Id;
392 pragma Inline (Get_Task_Body_Procedure);
393 -- Given an entity for a task type or subtype, retrieves the
394 -- Task_Body_Procedure field from the corresponding task type
397 function Has_Access_Values (T : Entity_Id) return Boolean;
398 -- Returns true if type or subtype T is an access type, or has a
399 -- component (at any recursive level) that is an access type. This
400 -- is a conservative predicate, if it is not known whether or not
401 -- T contains access values (happens for generic formals in some
402 -- cases), then False is returned.
404 type Alignment_Result is (Known_Compatible, Unknown, Known_Incompatible);
405 -- Result of Has_Compatible_Alignment test, description found below. Note
406 -- that the values are arranged in increasing order of problematicness.
408 function Has_Abstract_Interfaces (Tagged_Type : Entity_Id) return Boolean;
409 -- Returns true if Tagged_Type implements some abstract interface
411 function Has_Compatible_Alignment
413 Expr : Node_Id) return Alignment_Result;
414 -- Obj is an object entity, and expr is a node for an object reference. If
415 -- the alignment of the object referenced by Expr is known to be compatible
416 -- with the alignment of Obj (i.e. is larger or the same), then the result
417 -- is Known_Compatible. If the alignment of the object referenced by Expr
418 -- is known to be less than the alignment of Obj, then Known_Incompatible
419 -- is returned. If neither condition can be reliably established at compile
420 -- time, then Unknown is returned. This is used to determine if alignment
421 -- checks are required for address clauses, and also whether copies must
422 -- be made when objects are passed by reference.
424 -- Note: Known_Incompatible does not mean that at run time the alignment
425 -- of Expr is known to be wrong for Obj, just that it can be determined
426 -- that alignments have been explicitly or implicitly specified which
427 -- are incompatible (whereas Unknown means that even this is not known).
428 -- The appropriate reaction of a caller to Known_Incompatible is to treat
429 -- it as Unknown, but issue a warning that there may be an alignment error.
431 function Has_Declarations (N : Node_Id) return Boolean;
432 -- Determines if the node can have declarations
434 function Has_Discriminant_Dependent_Constraint
435 (Comp : Entity_Id) return Boolean;
436 -- Returns True if and only if Comp has a constrained subtype
437 -- that depends on a discriminant.
439 function Has_Infinities (E : Entity_Id) return Boolean;
440 -- Determines if the range of the floating-point type E includes
441 -- infinities. Returns False if E is not a floating-point type.
443 function Has_Null_Exclusion (N : Node_Id) return Boolean;
444 -- Determine whether node N has a null exclusion
446 function Has_Preelaborable_Initialization (E : Entity_Id) return Boolean;
447 -- Return True iff type E has preelaborable initialiation as defined in
448 -- Ada 2005 (see AI-161 for details of the definition of this attribute).
450 function Has_Private_Component (Type_Id : Entity_Id) return Boolean;
451 -- Check if a type has a (sub)component of a private type that has not
452 -- yet received a full declaration.
454 function Has_Stream (T : Entity_Id) return Boolean;
455 -- Tests if type T is derived from Ada.Streams.Root_Stream_Type, or
456 -- in the case of a composite type, has a component for which this
457 -- predicate is True, and if so returns True. Otherwise a result of
458 -- False means that there is no Stream type in sight. For a private
459 -- type, the test is applied to the underlying type (or returns False
460 -- if there is no underlying type).
462 function Has_Tagged_Component (Typ : Entity_Id) return Boolean;
463 -- Typ must be a composite type (array or record). This function is used
464 -- to check if '=' has to be expanded into a bunch component comparaisons.
466 function In_Instance return Boolean;
467 -- Returns True if the current scope is within a generic instance
469 function In_Instance_Body return Boolean;
470 -- Returns True if current scope is within the body of an instance, where
471 -- several semantic checks (e.g. accessibility checks) are relaxed.
473 function In_Instance_Not_Visible return Boolean;
474 -- Returns True if current scope is with the private part or the body of
475 -- an instance. Other semantic checks are suppressed in this context.
477 function In_Instance_Visible_Part return Boolean;
478 -- Returns True if current scope is within the visible part of a package
479 -- instance, where several additional semantic checks apply.
481 function In_Package_Body return Boolean;
482 -- Returns True if current scope is within a package body
484 function In_Subprogram_Or_Concurrent_Unit return Boolean;
485 -- Determines if the current scope is within a subprogram compilation
486 -- unit (inside a subprogram declaration, subprogram body, or generic
487 -- subprogram declaration) or within a task or protected body. The test
488 -- is for appearing anywhere within such a construct (that is it does not
489 -- need to be directly within).
491 function In_Visible_Part (Scope_Id : Entity_Id) return Boolean;
492 -- Determine whether a declaration occurs within the visible part of a
493 -- package specification. The package must be on the scope stack, and the
494 -- corresponding private part must not.
496 procedure Insert_Explicit_Dereference (N : Node_Id);
497 -- In a context that requires a composite or subprogram type and
498 -- where a prefix is an access type, rewrite the access type node
499 -- N (which is the prefix, e.g. of an indexed component) as an
500 -- explicit dereference.
502 function Is_AAMP_Float (E : Entity_Id) return Boolean;
503 -- Defined for all type entities. Returns True only for the base type
504 -- of float types with AAMP format. The particular format is determined
505 -- by the Digits_Value value which is 6 for the 32-bit floating point type,
506 -- or 9 for the 48-bit type. This is not an attribute function (like
507 -- VAX_Float) in order to not use up an extra flag and to prevent
508 -- the dependency of Einfo on Targparm which would be required for a
509 -- synthesized attribute.
511 function Is_Actual_Parameter (N : Node_Id) return Boolean;
512 -- Determines if N is an actual parameter in a subprogram call
514 function Is_Aliased_View (Obj : Node_Id) return Boolean;
515 -- Determine if Obj is an aliased view, i.e. the name of an
516 -- object to which 'Access or 'Unchecked_Access can apply.
518 function Is_Ancestor_Package
520 E2 : Entity_Id) return Boolean;
521 -- Determine whether package E1 is an ancestor of E2
523 function Is_Atomic_Object (N : Node_Id) return Boolean;
524 -- Determines if the given node denotes an atomic object in the sense
525 -- of the legality checks described in RM C.6(12).
527 function Is_Controlling_Limited_Procedure
528 (Proc_Nam : Entity_Id) return Boolean;
529 -- Ada 2005 (AI-345): Determine whether Proc_Nam is a primitive procedure
530 -- of a limited interface with a controlling first parameter.
532 function Is_Dependent_Component_Of_Mutable_Object
533 (Object : Node_Id) return Boolean;
534 -- Returns True if Object is the name of a subcomponent that
535 -- depends on discriminants of a variable whose nominal subtype
536 -- is unconstrained and not indefinite, and the variable is
537 -- not aliased. Otherwise returns False. The nodes passed
538 -- to this function are assumed to denote objects.
540 function Is_Dereferenced (N : Node_Id) return Boolean;
541 -- N is a subexpression node of an access type. This function returns
542 -- true if N appears as the prefix of a node that does a dereference
543 -- of the access value (selected/indexed component, explicit dereference
544 -- or a slice), and false otherwise.
546 function Is_Descendent_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean;
547 -- Returns True if type T1 is a descendent of type T2, and false otherwise.
548 -- This is the RM definition, a type is a descendent of another type if it
549 -- is the same type or is derived from a descendent of the other type.
551 function Is_Descendent_Of_Address (T1 : Entity_Id) return Boolean;
552 -- Returns True if type T1 is a descendent of Address or its base type.
553 -- Similar to calling Is_Descendent_Of with Base_Type (RTE (RE_Address))
554 -- except that it avoids creating an unconditional dependency on System.
556 function Is_False (U : Uint) return Boolean;
557 -- The argument is a Uint value which is the Boolean'Pos value of a
558 -- Boolean operand (i.e. is either 0 for False, or 1 for True). This
559 -- function simply tests if it is False (i.e. zero)
561 function Is_Fixed_Model_Number (U : Ureal; T : Entity_Id) return Boolean;
562 -- Returns True iff the number U is a model number of the fixed-
563 -- point type T, i.e. if it is an exact multiple of Small.
565 function Is_Fully_Initialized_Type (Typ : Entity_Id) return Boolean;
566 -- Typ is a type entity. This function returns true if this type is
567 -- fully initialized, meaning that an object of the type is fully
568 -- initialized. Note that initialization resulting from the use of
569 -- pragma Normalized_Scalars does not count. Note that this is only
570 -- used for the purpose of issuing warnings for objects that are
571 -- potentially referenced uninitialized. This means that the result
572 -- returned is not crucial, but probably should err on the side of
573 -- thinking things are fully initialized if it does not know.
575 function Is_Inherited_Operation (E : Entity_Id) return Boolean;
576 -- E is a subprogram. Return True is E is an implicit operation inherited
577 -- by a derived type declarations.
579 function Is_Library_Level_Entity (E : Entity_Id) return Boolean;
580 -- A library-level declaration is one that is accessible from Standard,
581 -- i.e. a library unit or an entity declared in a library package.
583 function Is_Local_Variable_Reference (Expr : Node_Id) return Boolean;
584 -- Determines whether Expr is a refeference to a variable or IN OUT
585 -- mode parameter of the current enclosing subprogram.
586 -- Why are OUT parameters not considered here ???
588 function Is_Object_Reference (N : Node_Id) return Boolean;
589 -- Determines if the tree referenced by N represents an object. Both
590 -- variable and constant objects return True (compare Is_Variable).
592 function Is_OK_Variable_For_Out_Formal (AV : Node_Id) return Boolean;
593 -- Used to test if AV is an acceptable formal for an OUT or IN OUT
594 -- formal. Note that the Is_Variable function is not quite the right
595 -- test because this is a case in which conversions whose expression
596 -- is a variable (in the Is_Variable sense) with a non-tagged type
597 -- target are considered view conversions and hence variables.
601 E2 : Entity_Id) return Boolean;
602 -- Determine whether E1 is a parent of E2. For a concurrent type, the
603 -- parent is the first element of its list of interface types; for other
604 -- types, this function provides the same result as Is_Ancestor.
606 function Is_Partially_Initialized_Type (Typ : Entity_Id) return Boolean;
607 -- Typ is a type entity. This function returns true if this type is
608 -- partly initialized, meaning that an object of the type is at least
609 -- partly initialized (in particular in the record case, that at least
610 -- one component has an initialization expression). Note that
611 -- initialization resulting from the use of pragma Normalized_Scalars does
614 function Is_Potentially_Persistent_Type (T : Entity_Id) return Boolean;
615 -- Determines if type T is a potentially persistent type. A potentially
616 -- persistent type is defined (recursively) as a scalar type, a non-tagged
617 -- record whose components are all of a potentially persistent type, or an
618 -- array with all static constraints whose component type is potentially
619 -- persistent. A private type is potentially persistent if the full type
620 -- is potentially persistent.
622 function Is_RCI_Pkg_Spec_Or_Body (Cunit : Node_Id) return Boolean;
623 -- Return True if a compilation unit is the specification or the
624 -- body of a remote call interface package.
626 function Is_Remote_Access_To_Class_Wide_Type (E : Entity_Id) return Boolean;
627 -- Return True if E is a remote access-to-class-wide type
629 function Is_Remote_Access_To_Subprogram_Type (E : Entity_Id) return Boolean;
630 -- Return True if E is a remote access to subprogram type
632 function Is_Remote_Call (N : Node_Id) return Boolean;
633 -- Return True if N denotes a potentially remote call
635 function Is_Renamed_Entry (Proc_Nam : Entity_Id) return Boolean;
636 -- Return True if Proc_Nam is a procedure renaming of an entry
638 function Is_Selector_Name (N : Node_Id) return Boolean;
639 -- Given an N_Identifier node N, determines if it is a Selector_Name.
640 -- As described in Sinfo, Selector_Names are special because they
641 -- represent use of the N_Identifier node for a true identifer, when
642 -- normally such nodes represent a direct name.
644 function Is_Statement (N : Node_Id) return Boolean;
645 -- Check if the node N is a statement node. Note that this includes
646 -- the case of procedure call statements (unlike the direct use of
647 -- the N_Statement_Other_Than_Procedure_Call subtype from Sinfo).
648 -- Note that a label is *not* a statement, and will return False.
650 function Is_Transfer (N : Node_Id) return Boolean;
651 -- Returns True if the node N is a statement which is known to cause
652 -- an unconditional transfer of control at runtime, i.e. the following
653 -- statement definitely will not be executed.
655 function Is_True (U : Uint) return Boolean;
656 -- The argument is a Uint value which is the Boolean'Pos value of a
657 -- Boolean operand (i.e. is either 0 for False, or 1 for True). This
658 -- function simply tests if it is True (i.e. non-zero)
660 function Is_Variable (N : Node_Id) return Boolean;
661 -- Determines if the tree referenced by N represents a variable, i.e.
662 -- can appear on the left side of an assignment. There is one situation,
663 -- namely formal parameters, in which non-tagged type conversions are
664 -- also considered variables, but Is_Variable returns False for such
665 -- cases, since it has no knowledge of the context. Note that this is
666 -- the point at which Assignment_OK is checked, and True is returned
667 -- for any tree thus marked.
669 function Is_Volatile_Object (N : Node_Id) return Boolean;
670 -- Determines if the given node denotes an volatile object in the sense
671 -- of the legality checks described in RM C.6(12). Note that the test
672 -- here is for something actually declared as volatile, not for an object
673 -- that gets treated as volatile (see Einfo.Treat_As_Volatile).
675 procedure Kill_Current_Values;
676 -- This procedure is called to clear all constant indications from all
677 -- entities in the current scope and in any parent scopes if the current
678 -- scope is a block or a package (and that recursion continues to the
679 -- top scope that is not a block or a package). This is used when the
680 -- sequential flow-of-control assumption is violated (occurence of a
681 -- label, head of a loop, or start of an exception handler). The effect
682 -- of the call is to clear the Constant_Value field (but we do not need
683 -- to clear the Is_True_Constant flag, since that only gets reset if
684 -- there really is an assignment somewhere in the entity scope). This
685 -- procedure also calls Kill_All_Checks, since this is a special case
686 -- of needing to forget saved values. This procedure also clears any
687 -- Is_Known_Non_Null flags in variables, constants or parameters
688 -- since these are also not known to be valid.
690 procedure Kill_Current_Values (Ent : Entity_Id);
691 -- This performs the same processing as described above for the form with
692 -- no argument, but for the specific entity given. The call has no effect
693 -- if the entity Ent is not for an object.
695 procedure Kill_Size_Check_Code (E : Entity_Id);
696 -- Called when an address clause or pragma Import is applied to an
697 -- entity. If the entity is a variable or a constant, and size check
698 -- code is present, this size check code is killed, since the object
699 -- will not be allocated by the program.
701 function Known_To_Be_Assigned (N : Node_Id) return Boolean;
702 -- The node N is an entity reference. This function determines whether the
703 -- reference is for sure an assignment of the entity, returning True if
704 -- so. This differs from May_Be_Lvalue in that it defaults in the other
705 -- direction. Cases which may possibly be assignments but are not known to
706 -- be may return True from May_Be_Lvalue, but False from this function.
708 function May_Be_Lvalue (N : Node_Id) return Boolean;
709 -- Determines if N could be an lvalue (e.g. an assignment left hand side).
710 -- An lvalue is defined as any expression which appears in a context where
711 -- a name is required by the syntax, and the identity, rather than merely
712 -- the value of the node is needed (for example, the prefix of an Access
713 -- attribute is in this category). Note that, as implied by the name, this
714 -- test is conservative. If it cannot be sure that N is NOT an lvalue, then
715 -- it returns True. It tries hard to get the answer right, but it is hard
716 -- to guarantee this in all cases. Note that it is more possible to give
717 -- correct answer if the tree is fully analyzed.
719 function Needs_One_Actual (E : Entity_Id) return Boolean;
720 -- Returns True if a function has defaults for all but its first
721 -- formal. Used in Ada 2005 mode to solve the syntactic ambiguity that
722 -- results from an indexing of a function call written in prefix form.
724 function New_External_Entity
726 Scope_Id : Entity_Id;
727 Sloc_Value : Source_Ptr;
728 Related_Id : Entity_Id;
730 Suffix_Index : Nat := 0;
731 Prefix : Character := ' ') return Entity_Id;
732 -- This function creates an N_Defining_Identifier node for an internal
733 -- created entity, such as an implicit type or subtype, or a record
734 -- initialization procedure. The entity name is constructed with a call
735 -- to New_External_Name (Related_Id, Suffix, Suffix_Index, Prefix), so
736 -- that the generated name may be referenced as a public entry, and the
737 -- Is_Public flag is set if needed (using Set_Public_Status). If the
738 -- entity is for a type or subtype, the size/align fields are initialized
739 -- to unknown (Uint_0).
741 function New_Internal_Entity
743 Scope_Id : Entity_Id;
744 Sloc_Value : Source_Ptr;
745 Id_Char : Character) return Entity_Id;
746 -- This function is similar to New_External_Entity, except that the
747 -- name is constructed by New_Internal_Name (Id_Char). This is used
748 -- when the resulting entity does not have to be referenced as a
749 -- public entity (and in this case Is_Public is not set).
751 procedure Next_Actual (Actual_Id : in out Node_Id);
752 pragma Inline (Next_Actual);
753 -- Next_Actual (N) is equivalent to N := Next_Actual (N)
755 function Next_Actual (Actual_Id : Node_Id) return Node_Id;
756 -- Find next actual parameter in declaration order. As described for
757 -- First_Actual, this is the next actual in the declaration order, not
758 -- the call order, so this does not correspond to simply taking the
759 -- next entry of the Parameter_Associations list. The argument is an
760 -- actual previously returned by a call to First_Actual or Next_Actual.
761 -- Note that the result produced is always an expression, not a parameter
762 -- assciation node, even if named notation was used.
764 procedure Normalize_Actuals
768 Success : out Boolean);
769 -- Reorders lists of actuals according to names of formals, value returned
770 -- in Success indicates sucess of reordering. For more details, see body.
771 -- Errors are reported only if Report is set to True.
773 procedure Note_Possible_Modification (N : Node_Id);
774 -- This routine is called if the sub-expression N maybe the target of
775 -- an assignment (e.g. it is the left side of an assignment, used as
776 -- an out parameters, or used as prefixes of access attributes). It
777 -- sets May_Be_Modified in the associated entity if there is one,
778 -- taking into account the rule that in the case of renamed objects,
779 -- it is the flag in the renamed object that must be set.
781 function Object_Access_Level (Obj : Node_Id) return Uint;
782 -- Return the accessibility level of the view of the object Obj.
783 -- For convenience, qualified expressions applied to object names
784 -- are also allowed as actuals for this function.
786 function Overrides_Synchronized_Primitive
788 First_Hom : Entity_Id;
789 Ifaces_List : Elist_Id;
790 In_Scope : Boolean := True) return Entity_Id;
791 -- Determine whether entry or subprogram Def_Id overrides a primitive
792 -- operation that belongs to one of the interfaces in Ifaces_List. A
793 -- specific homonym chain can be specified by setting First_Hom. Flag
794 -- In_Scope is used to designate whether the entry or subprogram was
795 -- declared inside the scope of the synchronized type or after. Return
796 -- the overriden entity or Empty.
798 function Private_Component (Type_Id : Entity_Id) return Entity_Id;
799 -- Returns some private component (if any) of the given Type_Id.
800 -- Used to enforce the rules on visibility of operations on composite
801 -- types, that depend on the full view of the component type. For a
802 -- record type there may be several such components, we just return
805 procedure Process_End_Label
809 -- N is a node whose End_Label is to be processed, generating all
810 -- appropriate cross-reference entries, and performing style checks
811 -- for any identifier references in the end label. Typ is either
812 -- 'e' or 't indicating the type of the cross-reference entity
813 -- (e for spec, t for body, see Lib.Xref spec for details). The
814 -- parameter Ent gives the entity to which the End_Label refers,
815 -- and to which cross-references are to be generated.
817 function Real_Convert (S : String) return Node_Id;
818 -- S is a possibly signed syntactically valid real literal. The result
819 -- returned is an N_Real_Literal node representing the literal value.
821 function Rep_To_Pos_Flag (E : Entity_Id; Loc : Source_Ptr) return Node_Id;
822 -- This is used to construct the second argument in a call to Rep_To_Pos
823 -- which is Standard_True if range checks are enabled (E is an entity to
824 -- which the Range_Checks_Suppressed test is applied), and Standard_False
825 -- if range checks are suppressed. Loc is the location for the node that
826 -- is returned (which is a New_Occurrence of the appropriate entity).
828 -- Note: one might think that it would be fine to always use True and
829 -- to ignore the suppress in this case, but it is generally better to
830 -- believe a request to suppress exceptions if possible, and further
831 -- more there is at least one case in the generated code (the code for
832 -- array assignment in a loop) that depends on this suppression.
834 procedure Require_Entity (N : Node_Id);
835 -- N is a node which should have an entity value if it is an entity name.
836 -- If not, then check if there were previous errors. If so, just fill
837 -- in with Any_Id and ignore. Otherwise signal a program error exception.
838 -- This is used as a defense mechanism against ill-formed trees caused by
839 -- previous errors (particularly in -gnatq mode).
841 function Requires_Transient_Scope (Id : Entity_Id) return Boolean;
842 -- E is a type entity. The result is True when temporaries of this
843 -- type need to be wrapped in a transient scope to be reclaimed
844 -- properly when a secondary stack is in use. Examples of types
845 -- requiring such wrapping are controlled types and variable-sized
846 -- types including unconstrained arrays
848 procedure Reset_Analyzed_Flags (N : Node_Id);
849 -- Reset the Analyzed flags in all nodes of the tree whose root is N
851 function Safe_To_Capture_Value
854 Cond : Boolean := False) return Boolean;
855 -- The caller is interested in capturing a value (either the current value,
856 -- or an indication that the value is non-null) for the given entity Ent.
857 -- This value can only be captured if sequential execution semantics can be
858 -- properly guaranteed so that a subsequent reference will indeed be sure
859 -- that this current value indication is correct. The node N is the
860 -- construct which resulted in the possible capture of the value (this
861 -- is used to check if we are in a conditional).
863 -- Cond is used to skip the test for being inside a conditional. It is used
864 -- in the case of capturing values from if/while tests, which already do a
865 -- proper job of handling scoping issues without this help.
867 -- The only entities whose values can be captured are OUT and IN OUT formal
868 -- parameters, and variables unless Cond is True, in which case we also
869 -- allow IN formals, loop parameters and constants, where we cannot ever
870 -- capture actual value information, but we can capture conditional tests.
872 function Same_Name (N1, N2 : Node_Id) return Boolean;
873 -- Determine if two (possibly expanded) names are the same name
875 function Same_Type (T1, T2 : Entity_Id) return Boolean;
876 -- Determines if T1 and T2 represent exactly the same type. Two types
877 -- are the same if they are identical, or if one is an unconstrained
878 -- subtype of the other, or they are both common subtypes of the same
879 -- type with identical constraints. The result returned is conservative.
880 -- It is True if the types are known to be the same, but a result of
881 -- False is indecisive (e.g. the compiler may not be able to tell that
882 -- two constraints are identical).
884 function Scope_Within_Or_Same (Scope1, Scope2 : Entity_Id) return Boolean;
885 -- Determines if the entity Scope1 is the same as Scope2, or if it is
886 -- inside it, where both entities represent scopes. Note that scopes
887 -- are only partially ordered, so Scope_Within_Or_Same (A,B) and
888 -- Scope_Within_Or_Same (B,A) can both be False for a given pair A,B.
890 function Scope_Within (Scope1, Scope2 : Entity_Id) return Boolean;
891 -- Like Scope_Within_Or_Same, except that this function returns
892 -- False in the case where Scope1 and Scope2 are the same scope.
894 procedure Set_Current_Entity (E : Entity_Id);
895 -- Establish the entity E as the currently visible definition of its
896 -- associated name (i.e. the Node_Id associated with its name)
898 procedure Set_Entity_With_Style_Check (N : Node_Id; Val : Entity_Id);
899 -- This procedure has the same calling sequence as Set_Entity, but
900 -- if Style_Check is set, then it calls a style checking routine which
901 -- can check identifier spelling style.
903 procedure Set_Name_Entity_Id (Id : Name_Id; Val : Entity_Id);
904 -- Sets the Entity_Id value associated with the given name, which is the
905 -- Id of the innermost visible entity with the given name. See the body
906 -- of package Sem_Ch8 for further details on the handling of visibility.
908 procedure Set_Next_Actual (Ass1_Id : Node_Id; Ass2_Id : Node_Id);
909 -- The arguments may be parameter associations, whose descendants
910 -- are the optional formal name and the actual parameter. Positional
911 -- parameters are already members of a list, and do not need to be
912 -- chained separately. See also First_Actual and Next_Actual.
914 procedure Set_Public_Status (Id : Entity_Id);
915 -- If an entity (visible or otherwise) is defined in a library
916 -- package, or a package that is itself public, then this subprogram
917 -- labels the entity public as well.
919 procedure Set_Scope_Is_Transient (V : Boolean := True);
920 -- Set the flag Is_Transient of the current scope
922 procedure Set_Size_Info (T1, T2 : Entity_Id);
923 -- Copies the Esize field and Has_Biased_Representation flag from sub(type)
924 -- entity T2 to (sub)type entity T1. Also copies the Is_Unsigned_Type flag
925 -- in the fixed-point and discrete cases, and also copies the alignment
926 -- value from T2 to T1. It does NOT copy the RM_Size field, which must be
927 -- separately set if this is required to be copied also.
929 function Scope_Is_Transient return Boolean;
930 -- True if the current scope is transient
932 function Static_Integer (N : Node_Id) return Uint;
933 -- This function analyzes the given expression node and then resolves it
934 -- as any integer type. If the result is static, then the value of the
935 -- universal expression is returned, otherwise an error message is output
936 -- and a value of No_Uint is returned.
938 function Statically_Different (E1, E2 : Node_Id) return Boolean;
939 -- Return True if it can be statically determined that the Expressions
940 -- E1 and E2 refer to different objects
942 function Subprogram_Access_Level (Subp : Entity_Id) return Uint;
943 -- Return the accessibility level of the view denoted by Subp
945 procedure Trace_Scope (N : Node_Id; E : Entity_Id; Msg : String);
946 -- Print debugging information on entry to each unit being analyzed
948 procedure Transfer_Entities (From : Entity_Id; To : Entity_Id);
949 -- Move a list of entities from one scope to another, and recompute
950 -- Is_Public based upon the new scope.
952 function Type_Access_Level (Typ : Entity_Id) return Uint;
953 -- Return the accessibility level of Typ
955 function Unit_Declaration_Node (Unit_Id : Entity_Id) return Node_Id;
956 -- Unit_Id is the simple name of a program unit, this function returns the
957 -- corresponding xxx_Declaration node for the entity. Also applies to the
958 -- body entities for subprograms, tasks and protected units, in which case
959 -- it returns the subprogram, task or protected body node for it. The unit
960 -- may be a child unit with any number of ancestors.
962 function Universal_Interpretation (Opnd : Node_Id) return Entity_Id;
963 -- Yields universal_Integer or Universal_Real if this is a candidate
965 function Unqualify (Expr : Node_Id) return Node_Id;
966 -- Removes any qualifications from Expr. For example, for T1'(T2'(X)),
967 -- this returns X. If Expr is not a qualified expression, returns Expr.
969 function Within_Init_Proc return Boolean;
970 -- Determines if Current_Scope is within an init proc
972 procedure Wrong_Type (Expr : Node_Id; Expected_Type : Entity_Id);
973 -- Output error message for incorrectly typed expression. Expr is the
974 -- node for the incorrectly typed construct (Etype (Expr) is the type
975 -- found), and Expected_Type is the entity for the expected type. Note
976 -- that Expr does not have to be a subexpression, anything with an
977 -- Etype field may be used.
980 pragma Inline (Current_Entity);
981 pragma Inline (Get_Name_Entity_Id);
982 pragma Inline (Is_False);
983 pragma Inline (Is_Statement);
984 pragma Inline (Is_True);
985 pragma Inline (Set_Current_Entity);
986 pragma Inline (Set_Name_Entity_Id);
987 pragma Inline (Set_Size_Info);
988 pragma Inline (Unqualify);