gcc:
[official-gcc.git] / gcc / ada / sem_util.ads
blobad2404b372e5e1234ae4f144c745d44415bb9b98
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ U T I L --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
21 -- --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 -- --
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;
34 package Sem_Util is
36 procedure Add_Access_Type_To_Process (E : Entity_Id; A : Entity_Id);
37 -- Add A to the list of access types to process when expanding the
38 -- freeze node of E.
40 function Alignment_In_Bits (E : Entity_Id) return Uint;
41 -- If the alignment of the type or object E is currently known to the
42 -- compiler, then this function returns the alignment value in bits.
43 -- Otherwise Uint_0 is returned, indicating that the alignment of the
44 -- entity is not yet known to the compiler.
46 procedure Apply_Compile_Time_Constraint_Error
47 (N : Node_Id;
48 Msg : String;
49 Reason : RT_Exception_Code;
50 Ent : Entity_Id := Empty;
51 Typ : Entity_Id := Empty;
52 Loc : Source_Ptr := No_Location;
53 Rep : Boolean := True;
54 Warn : Boolean := False);
55 -- N is a subexpression which will raise constraint error when evaluated
56 -- at runtime. Msg is a message that explains the reason for raising the
57 -- exception. The last character is ? if the message is always a warning,
58 -- even in Ada 95, and is not a ? if the message represents an illegality
59 -- (because of violation of static expression rules) in Ada 95 (but not
60 -- in Ada 83). Typically this routine posts all messages at the Sloc of
61 -- node N. However, if Loc /= No_Location, Loc is the Sloc used to output
62 -- the message. After posting the appropriate message, and if the flag
63 -- Rep is set, this routine replaces the expression with an appropriate
64 -- N_Raise_Constraint_Error node using the given Reason code. This node
65 -- is then marked as being static if the original node is static, but
66 -- sets the flag Raises_Constraint_Error, preventing further evaluation.
67 -- The error message may contain a } or & insertion character. This
68 -- normally references Etype (N), unless the Ent argument is given
69 -- explicitly, in which case it is used instead. The type of the raise
70 -- node that is built is normally Etype (N), but if the Typ parameter
71 -- is present, this is used instead. Warn is normally False. If it is
72 -- True then the message is treated as a warning even though it does
73 -- not end with a ? (this is used when the caller wants to parametrize
74 -- whether an error or warning is given.
76 function Build_Actual_Subtype
77 (T : Entity_Id;
78 N : Node_Or_Entity_Id) return Node_Id;
79 -- Build an anonymous subtype for an entity or expression, using the
80 -- bounds of the entity or the discriminants of the enclosing record.
81 -- T is the type for which the actual subtype is required, and N is either
82 -- a defining identifier, or any subexpression.
84 function Build_Actual_Subtype_Of_Component
85 (T : Entity_Id;
86 N : Node_Id) return Node_Id;
87 -- Determine whether a selected component has a type that depends on
88 -- discriminants, and build actual subtype for it if so.
90 function Build_Default_Subtype
91 (T : Entity_Id;
92 N : Node_Id) return Entity_Id;
93 -- If T is an unconstrained type with defaulted discriminants, build a
94 -- subtype constrained by the default values, insert the subtype
95 -- declaration in the tree before N, and return the entity of that
96 -- subtype. Otherwise, simply return T.
98 function Build_Discriminal_Subtype_Of_Component
99 (T : Entity_Id) return Node_Id;
100 -- Determine whether a record component has a type that depends on
101 -- discriminants, and build actual subtype for it if so.
103 procedure Build_Elaboration_Entity (N : Node_Id; Spec_Id : Entity_Id);
104 -- Given a compilation unit node N, allocate an elaboration boolean for
105 -- the compilation unit, and install it in the Elaboration_Entity field
106 -- of Spec_Id, the entity for the compilation unit.
108 function Cannot_Raise_Constraint_Error (Expr : Node_Id) return Boolean;
109 -- Returns True if the expression cannot possibly raise Constraint_Error.
110 -- The response is conservative in the sense that a result of False does
111 -- not necessarily mean that CE could be raised, but a response of True
112 -- means that for sure CE cannot be raised.
114 procedure Check_Fully_Declared (T : Entity_Id; N : Node_Id);
115 -- Verify that the full declaration of type T has been seen. If not,
116 -- place error message on node N. Used in object declarations, type
117 -- conversions, qualified expressions.
119 procedure Check_Potentially_Blocking_Operation (N : Node_Id);
120 -- N is one of the statement forms that is a potentially blocking
121 -- operation. If it appears within a protected action, emit warning.
123 procedure Check_VMS (Construct : Node_Id);
124 -- Check that this the target is OpenVMS, and if so, return with
125 -- no effect, otherwise post an error noting this can only be used
126 -- with OpenVMS ports. The argument is the construct in question
127 -- and is used to post the error message.
129 procedure Collect_Abstract_Interfaces
130 (T : Entity_Id;
131 Ifaces_List : out Elist_Id;
132 Exclude_Parent_Interfaces : Boolean := False);
133 -- Ada 2005 (AI-251): Collect whole list of abstract interfaces that are
134 -- directly or indirectly implemented by T. Exclude_Parent_Interfaces is
135 -- used to avoid addition of inherited interfaces to the generated list.
137 function Collect_Primitive_Operations (T : Entity_Id) return Elist_Id;
138 -- Called upon type derivation and extension. We scan the declarative
139 -- part in which the type appears, and collect subprograms that have
140 -- one subsidiary subtype of the type. These subprograms can only
141 -- appear after the type itself.
143 procedure Collect_Synchronized_Interfaces
144 (Typ : Entity_Id;
145 Ifaces_List : out Elist_Id);
146 -- Similar to Collect_Abstract_Interfaces, but tailored to task and
147 -- protected types.
149 function Compile_Time_Constraint_Error
150 (N : Node_Id;
151 Msg : String;
152 Ent : Entity_Id := Empty;
153 Loc : Source_Ptr := No_Location;
154 Warn : Boolean := False) return Node_Id;
155 -- This is similar to Apply_Compile_Time_Constraint_Error in that it
156 -- generates a warning (or error) message in the same manner, but it does
157 -- not replace any nodes. For convenience, the function always returns its
158 -- first argument. The message is a warning if the message ends with ?, or
159 -- we are operating in Ada 83 mode, or if the Warn parameter is set to
160 -- True.
162 procedure Conditional_Delay (New_Ent, Old_Ent : Entity_Id);
163 -- Sets the Has_Delayed_Freeze flag of New if the Delayed_Freeze flag
164 -- of Old is set and Old has no yet been Frozen (i.e. Is_Frozen is false);
166 function Current_Entity (N : Node_Id) return Entity_Id;
167 -- Find the currently visible definition for a given identifier, that is to
168 -- say the first entry in the visibility chain for the Chars of N.
170 function Current_Entity_In_Scope (N : Node_Id) return Entity_Id;
171 -- Find whether there is a previous definition for identifier N in the
172 -- current scope. Because declarations for a scope are not necessarily
173 -- contiguous (e.g. for packages) the first entry on the visibility chain
174 -- for N is not necessarily in the current scope.
176 function Current_Scope return Entity_Id;
177 -- Get entity representing current scope
179 function Current_Subprogram return Entity_Id;
180 -- Returns current enclosing subprogram. If Current_Scope is a subprogram,
181 -- then that is what is returned, otherwise the Enclosing_Subprogram of
182 -- the Current_Scope is returned. The returned value is Empty if this
183 -- is called from a library package which is not within any subprogram.
185 function Defining_Entity (N : Node_Id) return Entity_Id;
186 -- Given a declaration N, returns the associated defining entity. If
187 -- the declaration has a specification, the entity is obtained from
188 -- the specification. If the declaration has a defining unit name,
189 -- then the defining entity is obtained from the defining unit name
190 -- ignoring any child unit prefixes.
192 function Denotes_Discriminant
193 (N : Node_Id;
194 Check_Concurrent : Boolean := False) return Boolean;
195 -- Returns True if node N is an Entity_Name node for a discriminant.
196 -- If the flag Check_Concurrent is true, function also returns true
197 -- when N denotes the discriminal of the discriminant of a concurrent
198 -- type. This is necessary to disable some optimizations on private
199 -- components of protected types, and constraint checks on entry
200 -- families constrained by discriminants.
202 function Depends_On_Discriminant (N : Node_Id) return Boolean;
203 -- Returns True if N denotes a discriminant or if N is a range, a subtype
204 -- indication or a scalar subtype where one of the bounds is a
205 -- discriminant.
207 function Designate_Same_Unit
208 (Name1 : Node_Id;
209 Name2 : Node_Id) return Boolean;
210 -- Return true if Name1 and Name2 designate the same unit name;
211 -- each of these names is supposed to be a selected component name,
212 -- an expanded name, a defining program unit name or an identifier
214 function Enclosing_Generic_Body
215 (N : Node_Id) return Node_Id;
216 -- Returns the Node_Id associated with the innermost enclosing
217 -- generic body, if any. If none, then returns Empty.
219 function Enclosing_Generic_Unit
220 (N : Node_Id) return Node_Id;
221 -- Returns the Node_Id associated with the innermost enclosing
222 -- generic unit, if any. If none, then returns Empty.
224 function Enclosing_Lib_Unit_Entity return Entity_Id;
225 -- Returns the entity of enclosing N_Compilation_Unit Node which is the
226 -- root of the current scope (which must not be Standard_Standard, and
227 -- the caller is responsible for ensuring this condition).
229 function Enclosing_Lib_Unit_Node (N : Node_Id) return Node_Id;
230 -- Returns the enclosing N_Compilation_Unit Node that is the root
231 -- of a subtree containing N.
233 function Enclosing_Subprogram (E : Entity_Id) return Entity_Id;
234 -- Utility function to return the Ada entity of the subprogram enclosing
235 -- the entity E, if any. Returns Empty if no enclosing subprogram.
237 procedure Ensure_Freeze_Node (E : Entity_Id);
238 -- Make sure a freeze node is allocated for entity E. If necessary,
239 -- build and initialize a new freeze node and set Has_Delayed_Freeze
240 -- true for entity E.
242 procedure Enter_Name (Def_Id : Entity_Id);
243 -- Insert new name in symbol table of current scope with check for
244 -- duplications (error message is issued if a conflict is found)
245 -- Note: Enter_Name is not used for overloadable entities, instead
246 -- these are entered using Sem_Ch6.Enter_Overloadable_Entity.
248 procedure Explain_Limited_Type (T : Entity_Id; N : Node_Id);
249 -- This procedure is called after issuing a message complaining
250 -- about an inappropriate use of limited type T. If useful, it
251 -- adds additional continuation lines to the message explaining
252 -- why type T is limited. Messages are placed at node N.
254 function Find_Corresponding_Discriminant
255 (Id : Node_Id;
256 Typ : Entity_Id) return Entity_Id;
257 -- Because discriminants may have different names in a generic unit
258 -- and in an instance, they are resolved positionally when possible.
259 -- A reference to a discriminant carries the discriminant that it
260 -- denotes when analyzed. Subsequent uses of this id on a different
261 -- type denote the discriminant at the same position in this new type.
263 function First_Actual (Node : Node_Id) return Node_Id;
264 -- Node is an N_Function_Call or N_Procedure_Call_Statement node. The
265 -- result returned is the first actual parameter in declaration order
266 -- (not the order of parameters as they appeared in the source, which
267 -- can be quite different as a result of the use of named parameters).
268 -- Empty is returned for a call with no parameters. The procedure for
269 -- iterating through the actuals in declaration order is to use this
270 -- function to find the first actual, and then use Next_Actual to obtain
271 -- the next actual in declaration order. Note that the value returned
272 -- is always the expression (not the N_Parameter_Association nodes
273 -- even if named association is used).
275 function Full_Qualified_Name (E : Entity_Id) return String_Id;
276 -- Generates the string literal corresponding to the E's full qualified
277 -- name in upper case. An ASCII.NUL is appended as the last character.
278 -- The names in the string are generated by Namet.Get_Decoded_Name_String.
280 function Find_Static_Alternative (N : Node_Id) return Node_Id;
281 -- N is a case statement whose expression is a compile-time value.
282 -- Determine the alternative chosen, so that the code of non-selected
283 -- alternatives, and the warnings that may apply to them, are removed.
285 procedure Gather_Components
286 (Typ : Entity_Id;
287 Comp_List : Node_Id;
288 Governed_By : List_Id;
289 Into : Elist_Id;
290 Report_Errors : out Boolean);
291 -- The purpose of this procedure is to gather the valid components in a
292 -- record type according to the values of its discriminants, in order to
293 -- validate the components of a record aggregate.
295 -- Typ is the type of the aggregate when its constrained discriminants
296 -- need to be collected, otherwise it is Empty.
298 -- Comp_List is an N_Component_List node.
300 -- Governed_By is a list of N_Component_Association nodes, where each
301 -- choice list contains the name of a discriminant and the expression
302 -- field gives its value. The values of the discriminants governing
303 -- the (possibly nested) variant parts in Comp_List are found in this
304 -- Component_Association List.
306 -- Into is the list where the valid components are appended. Note that
307 -- Into need not be an Empty list. If it's not, components are attached
308 -- to its tail.
310 -- Report_Errors is set to True if the values of the discriminants are
311 -- non-static.
313 -- This procedure is also used when building a record subtype. If the
314 -- discriminant constraint of the subtype is static, the components of the
315 -- subtype are only those of the variants selected by the values of the
316 -- discriminants. Otherwise all components of the parent must be included
317 -- in the subtype for semantic analysis.
319 function Get_Actual_Subtype (N : Node_Id) return Entity_Id;
320 -- Given a node for an expression, obtain the actual subtype of the
321 -- expression. In the case of a parameter where the formal is an
322 -- unconstrained array or discriminated type, this will be the
323 -- previously constructed subtype of the actual. Note that this is
324 -- not quite the "Actual Subtype" of the RM, since it is always
325 -- a constrained type, i.e. it is the subtype of the value of the
326 -- actual. The actual subtype is also returned in other cases where
327 -- it has already been constructed for an object. Otherwise the
328 -- expression type is returned unchanged, except for the case of an
329 -- unconstrained array type, where an actual subtype is created, using
330 -- Insert_Actions if necessary to insert any associated actions.
332 function Get_Actual_Subtype_If_Available (N : Node_Id) return Entity_Id;
333 -- This is like Get_Actual_Subtype, except that it never constructs an
334 -- actual subtype. If an actual subtype is already available, i.e. the
335 -- Actual_Subtype field of the corresponding entity is set, then it is
336 -- returned. Otherwise the Etype of the node is returned.
338 function Get_Default_External_Name (E : Node_Or_Entity_Id) return Node_Id;
339 -- This is used to construct the string literal node representing a
340 -- default external name, i.e. one that is constructed from the name
341 -- of an entity, or (in the case of extended DEC import/export pragmas,
342 -- an identifier provided as the external name. Letters in the name are
343 -- according to the setting of Opt.External_Name_Default_Casing.
345 function Get_Generic_Entity (N : Node_Id) return Entity_Id;
346 -- Returns the true generic entity in an instantiation. If the name in
347 -- the instantiation is a renaming, the function returns the renamed
348 -- generic.
350 procedure Get_Index_Bounds (N : Node_Id; L, H : out Node_Id);
351 -- This procedure assigns to L and H respectively the values of the
352 -- low and high bounds of node N, which must be a range, subtype
353 -- indication, or the name of a scalar subtype. The result in L, H
354 -- may be set to Error if there was an earlier error in the range.
356 function Get_Enum_Lit_From_Pos
357 (T : Entity_Id;
358 Pos : Uint;
359 Loc : Source_Ptr) return Entity_Id;
360 -- This function obtains the E_Enumeration_Literal entity for the
361 -- specified value from the enumneration type or subtype T. The
362 -- second argument is the Pos value, which is assumed to be in range.
363 -- The third argument supplies a source location for constructed
364 -- nodes returned by this function.
366 procedure Get_Library_Unit_Name_String (Decl_Node : Node_Id);
367 -- Retrieve the fully expanded name of the library unit declared by
368 -- Decl_Node into the name buffer.
370 function Get_Name_Entity_Id (Id : Name_Id) return Entity_Id;
371 -- An entity value is associated with each name in the name table. The
372 -- Get_Name_Entity_Id function fetches the Entity_Id of this entity,
373 -- which is the innermost visible entity with the given name. See the
374 -- body of Sem_Ch8 for further details on handling of entity visibility.
376 function Get_Subprogram_Entity (Nod : Node_Id) return Entity_Id;
377 -- Nod is either a procedure call statement, or a function call, or
378 -- an accept statement node. This procedure finds the Entity_Id of the
379 -- related subprogram or entry and returns it, or if no subprogram can
380 -- be found, returns Empty.
382 function Get_Referenced_Object (N : Node_Id) return Node_Id;
383 -- Given a node, return the renamed object if the node represents
384 -- a renamed object, otherwise return the node unchanged. The node
385 -- may represent an arbitrary expression.
387 function Get_Subprogram_Body (E : Entity_Id) return Node_Id;
388 -- Given the entity for a subprogram (E_Function or E_Procedure),
389 -- return the corresponding N_Subprogram_Body node. If the corresponding
390 -- body of the declaration is missing (as for an imported subprogram)
391 -- return Empty.
393 function Get_Task_Body_Procedure (E : Entity_Id) return Node_Id;
394 pragma Inline (Get_Task_Body_Procedure);
395 -- Given an entity for a task type or subtype, retrieves the
396 -- Task_Body_Procedure field from the corresponding task type
397 -- declaration.
399 function Has_Access_Values (T : Entity_Id) return Boolean;
400 -- Returns true if type or subtype T is an access type, or has a
401 -- component (at any recursive level) that is an access type. This
402 -- is a conservative predicate, if it is not known whether or not
403 -- T contains access values (happens for generic formals in some
404 -- cases), then False is returned.
406 type Alignment_Result is (Known_Compatible, Unknown, Known_Incompatible);
407 -- Result of Has_Compatible_Alignment test, description found below. Note
408 -- that the values are arranged in increasing order of problematicness.
410 function Has_Abstract_Interfaces (Tagged_Type : Entity_Id) return Boolean;
411 -- Returns true if Tagged_Type implements some abstract interface
413 function Has_Compatible_Alignment
414 (Obj : Entity_Id;
415 Expr : Node_Id) return Alignment_Result;
416 -- Obj is an object entity, and expr is a node for an object reference. If
417 -- the alignment of the object referenced by Expr is known to be compatible
418 -- with the alignment of Obj (i.e. is larger or the same), then the result
419 -- is Known_Compatible. If the alignment of the object referenced by Expr
420 -- is known to be less than the alignment of Obj, then Known_Incompatible
421 -- is returned. If neither condition can be reliably established at compile
422 -- time, then Unknown is returned. This is used to determine if alignment
423 -- checks are required for address clauses, and also whether copies must
424 -- be made when objects are passed by reference.
426 -- Note: Known_Incompatible does not mean that at run time the alignment
427 -- of Expr is known to be wrong for Obj, just that it can be determined
428 -- that alignments have been explicitly or implicitly specified which
429 -- are incompatible (whereas Unknown means that even this is not known).
430 -- The appropriate reaction of a caller to Known_Incompatible is to treat
431 -- it as Unknown, but issue a warning that there may be an alignment error.
433 function Has_Declarations (N : Node_Id) return Boolean;
434 -- Determines if the node can have declarations
436 function Has_Discriminant_Dependent_Constraint
437 (Comp : Entity_Id) return Boolean;
438 -- Returns True if and only if Comp has a constrained subtype
439 -- that depends on a discriminant.
441 function Has_Infinities (E : Entity_Id) return Boolean;
442 -- Determines if the range of the floating-point type E includes
443 -- infinities. Returns False if E is not a floating-point type.
445 function Has_Null_Exclusion (N : Node_Id) return Boolean;
446 -- Determine whether node N has a null exclusion
448 function Has_Preelaborable_Initialization (E : Entity_Id) return Boolean;
449 -- Return True iff type E has preelaborable initialiation as defined in
450 -- Ada 2005 (see AI-161 for details of the definition of this attribute).
452 function Has_Private_Component (Type_Id : Entity_Id) return Boolean;
453 -- Check if a type has a (sub)component of a private type that has not
454 -- yet received a full declaration.
456 function Has_Stream (T : Entity_Id) return Boolean;
457 -- Tests if type T is derived from Ada.Streams.Root_Stream_Type, or
458 -- in the case of a composite type, has a component for which this
459 -- predicate is True, and if so returns True. Otherwise a result of
460 -- False means that there is no Stream type in sight. For a private
461 -- type, the test is applied to the underlying type (or returns False
462 -- if there is no underlying type).
464 function Has_Tagged_Component (Typ : Entity_Id) return Boolean;
465 -- Typ must be a composite type (array or record). This function is used
466 -- to check if '=' has to be expanded into a bunch component comparaisons.
468 function In_Instance return Boolean;
469 -- Returns True if the current scope is within a generic instance
471 function In_Instance_Body return Boolean;
472 -- Returns True if current scope is within the body of an instance, where
473 -- several semantic checks (e.g. accessibility checks) are relaxed.
475 function In_Instance_Not_Visible return Boolean;
476 -- Returns True if current scope is with the private part or the body of
477 -- an instance. Other semantic checks are suppressed in this context.
479 function In_Instance_Visible_Part return Boolean;
480 -- Returns True if current scope is within the visible part of a package
481 -- instance, where several additional semantic checks apply.
483 function In_Package_Body return Boolean;
484 -- Returns True if current scope is within a package body
486 function In_Subprogram_Or_Concurrent_Unit return Boolean;
487 -- Determines if the current scope is within a subprogram compilation
488 -- unit (inside a subprogram declaration, subprogram body, or generic
489 -- subprogram declaration) or within a task or protected body. The test
490 -- is for appearing anywhere within such a construct (that is it does not
491 -- need to be directly within).
493 function In_Visible_Part (Scope_Id : Entity_Id) return Boolean;
494 -- Determine whether a declaration occurs within the visible part of a
495 -- package specification. The package must be on the scope stack, and the
496 -- corresponding private part must not.
498 procedure Insert_Explicit_Dereference (N : Node_Id);
499 -- In a context that requires a composite or subprogram type and
500 -- where a prefix is an access type, rewrite the access type node
501 -- N (which is the prefix, e.g. of an indexed component) as an
502 -- explicit dereference.
504 function Is_AAMP_Float (E : Entity_Id) return Boolean;
505 -- Defined for all type entities. Returns True only for the base type
506 -- of float types with AAMP format. The particular format is determined
507 -- by the Digits_Value value which is 6 for the 32-bit floating point type,
508 -- or 9 for the 48-bit type. This is not an attribute function (like
509 -- VAX_Float) in order to not use up an extra flag and to prevent
510 -- the dependency of Einfo on Targparm which would be required for a
511 -- synthesized attribute.
513 function Is_Actual_Parameter (N : Node_Id) return Boolean;
514 -- Determines if N is an actual parameter in a subprogram call
516 function Is_Aliased_View (Obj : Node_Id) return Boolean;
517 -- Determine if Obj is an aliased view, i.e. the name of an
518 -- object to which 'Access or 'Unchecked_Access can apply.
520 function Is_Ancestor_Package
521 (E1 : Entity_Id;
522 E2 : Entity_Id) return Boolean;
523 -- Determine whether package E1 is an ancestor of E2
525 function Is_Atomic_Object (N : Node_Id) return Boolean;
526 -- Determines if the given node denotes an atomic object in the sense
527 -- of the legality checks described in RM C.6(12).
529 function Is_Controlling_Limited_Procedure
530 (Proc_Nam : Entity_Id) return Boolean;
531 -- Ada 2005 (AI-345): Determine whether Proc_Nam is a primitive procedure
532 -- of a limited interface with a controlling first parameter.
534 function Is_Dependent_Component_Of_Mutable_Object
535 (Object : Node_Id) return Boolean;
536 -- Returns True if Object is the name of a subcomponent that
537 -- depends on discriminants of a variable whose nominal subtype
538 -- is unconstrained and not indefinite, and the variable is
539 -- not aliased. Otherwise returns False. The nodes passed
540 -- to this function are assumed to denote objects.
542 function Is_Dereferenced (N : Node_Id) return Boolean;
543 -- N is a subexpression node of an access type. This function returns
544 -- true if N appears as the prefix of a node that does a dereference
545 -- of the access value (selected/indexed component, explicit dereference
546 -- or a slice), and false otherwise.
548 function Is_Descendent_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean;
549 -- Returns True if type T1 is a descendent of type T2, and false otherwise.
550 -- This is the RM definition, a type is a descendent of another type if it
551 -- is the same type or is derived from a descendent of the other type.
553 function Is_Descendent_Of_Address (T1 : Entity_Id) return Boolean;
554 -- Returns True if type T1 is a descendent of Address or its base type.
555 -- Similar to calling Is_Descendent_Of with Base_Type (RTE (RE_Address))
556 -- except that it avoids creating an unconditional dependency on System.
558 function Is_False (U : Uint) return Boolean;
559 -- The argument is a Uint value which is the Boolean'Pos value of a
560 -- Boolean operand (i.e. is either 0 for False, or 1 for True). This
561 -- function simply tests if it is False (i.e. zero)
563 function Is_Fixed_Model_Number (U : Ureal; T : Entity_Id) return Boolean;
564 -- Returns True iff the number U is a model number of the fixed-
565 -- point type T, i.e. if it is an exact multiple of Small.
567 function Is_Fully_Initialized_Type (Typ : Entity_Id) return Boolean;
568 -- Typ is a type entity. This function returns true if this type is
569 -- fully initialized, meaning that an object of the type is fully
570 -- initialized. Note that initialization resulting from the use of
571 -- pragma Normalized_Scalars does not count. Note that this is only
572 -- used for the purpose of issuing warnings for objects that are
573 -- potentially referenced uninitialized. This means that the result
574 -- returned is not crucial, but probably should err on the side of
575 -- thinking things are fully initialized if it does not know.
577 function Is_Inherited_Operation (E : Entity_Id) return Boolean;
578 -- E is a subprogram. Return True is E is an implicit operation inherited
579 -- by a derived type declarations.
581 function Is_Library_Level_Entity (E : Entity_Id) return Boolean;
582 -- A library-level declaration is one that is accessible from Standard,
583 -- i.e. a library unit or an entity declared in a library package.
585 function Is_Local_Variable_Reference (Expr : Node_Id) return Boolean;
586 -- Determines whether Expr is a refeference to a variable or IN OUT
587 -- mode parameter of the current enclosing subprogram.
588 -- Why are OUT parameters not considered here ???
590 function Is_Object_Reference (N : Node_Id) return Boolean;
591 -- Determines if the tree referenced by N represents an object. Both
592 -- variable and constant objects return True (compare Is_Variable).
594 function Is_OK_Variable_For_Out_Formal (AV : Node_Id) return Boolean;
595 -- Used to test if AV is an acceptable formal for an OUT or IN OUT
596 -- formal. Note that the Is_Variable function is not quite the right
597 -- test because this is a case in which conversions whose expression
598 -- is a variable (in the Is_Variable sense) with a non-tagged type
599 -- target are considered view conversions and hence variables.
601 function Is_Partially_Initialized_Type (Typ : Entity_Id) return Boolean;
602 -- Typ is a type entity. This function returns true if this type is
603 -- partly initialized, meaning that an object of the type is at least
604 -- partly initialized (in particular in the record case, that at least
605 -- one field has an initialization expression). Note that initialization
606 -- resulting from the use of pragma Normalized_Scalars does not count.
608 function Is_Potentially_Persistent_Type (T : Entity_Id) return Boolean;
609 -- Determines if type T is a potentially persistent type. A potentially
610 -- persistent type is defined (recursively) as a scalar type, a non-tagged
611 -- record whose components are all of a potentially persistent type, or an
612 -- array with all static constraints whose component type is potentially
613 -- persistent. A private type is potentially persistent if the full type
614 -- is potentially persistent.
616 function Is_RCI_Pkg_Spec_Or_Body (Cunit : Node_Id) return Boolean;
617 -- Return True if a compilation unit is the specification or the
618 -- body of a remote call interface package.
620 function Is_Remote_Access_To_Class_Wide_Type (E : Entity_Id) return Boolean;
621 -- Return True if E is a remote access-to-class-wide-limited_private type
623 function Is_Remote_Access_To_Subprogram_Type (E : Entity_Id) return Boolean;
624 -- Return True if E is a remote access to subprogram type
626 function Is_Remote_Call (N : Node_Id) return Boolean;
627 -- Return True if N denotes a potentially remote call
629 function Is_Renamed_Entry (Proc_Nam : Entity_Id) return Boolean;
630 -- Return True if Proc_Nam is a procedure renaming of an entry
632 function Is_Selector_Name (N : Node_Id) return Boolean;
633 -- Given an N_Identifier node N, determines if it is a Selector_Name.
634 -- As described in Sinfo, Selector_Names are special because they
635 -- represent use of the N_Identifier node for a true identifer, when
636 -- normally such nodes represent a direct name.
638 function Is_Statement (N : Node_Id) return Boolean;
639 -- Check if the node N is a statement node. Note that this includes
640 -- the case of procedure call statements (unlike the direct use of
641 -- the N_Statement_Other_Than_Procedure_Call subtype from Sinfo).
642 -- Note that a label is *not* a statement, and will return False.
644 function Is_Transfer (N : Node_Id) return Boolean;
645 -- Returns True if the node N is a statement which is known to cause
646 -- an unconditional transfer of control at runtime, i.e. the following
647 -- statement definitely will not be executed.
649 function Is_True (U : Uint) return Boolean;
650 -- The argument is a Uint value which is the Boolean'Pos value of a
651 -- Boolean operand (i.e. is either 0 for False, or 1 for True). This
652 -- function simply tests if it is True (i.e. non-zero)
654 function Is_Variable (N : Node_Id) return Boolean;
655 -- Determines if the tree referenced by N represents a variable, i.e.
656 -- can appear on the left side of an assignment. There is one situation,
657 -- namely formal parameters, in which non-tagged type conversions are
658 -- also considered variables, but Is_Variable returns False for such
659 -- cases, since it has no knowledge of the context. Note that this is
660 -- the point at which Assignment_OK is checked, and True is returned
661 -- for any tree thus marked.
663 function Is_Volatile_Object (N : Node_Id) return Boolean;
664 -- Determines if the given node denotes an volatile object in the sense
665 -- of the legality checks described in RM C.6(12). Note that the test
666 -- here is for something actually declared as volatile, not for an object
667 -- that gets treated as volatile (see Einfo.Treat_As_Volatile).
669 procedure Kill_Current_Values;
670 -- This procedure is called to clear all constant indications from all
671 -- entities in the current scope and in any parent scopes if the current
672 -- scope is a block or a package (and that recursion continues to the
673 -- top scope that is not a block or a package). This is used when the
674 -- sequential flow-of-control assumption is violated (occurence of a
675 -- label, head of a loop, or start of an exception handler). The effect
676 -- of the call is to clear the Constant_Value field (but we do not need
677 -- to clear the Is_True_Constant flag, since that only gets reset if
678 -- there really is an assignment somewhere in the entity scope). This
679 -- procedure also calls Kill_All_Checks, since this is a special case
680 -- of needing to forget saved values. This procedure also clears any
681 -- Is_Known_Non_Null flags in variables, constants or parameters
682 -- since these are also not known to be valid.
684 procedure Kill_Current_Values (Ent : Entity_Id);
685 -- This performs the same processing as described above for the form with
686 -- no argument, but for the specific entity given. The call has no effect
687 -- if the entity Ent is not for an object.
689 procedure Kill_Size_Check_Code (E : Entity_Id);
690 -- Called when an address clause or pragma Import is applied to an
691 -- entity. If the entity is a variable or a constant, and size check
692 -- code is present, this size check code is killed, since the object
693 -- will not be allocated by the program.
695 function Known_To_Be_Assigned (N : Node_Id) return Boolean;
696 -- The node N is an entity reference. This function determines whether the
697 -- reference is for sure an assignment of the entity, returning True if
698 -- so. This differs from May_Be_Lvalue in that it defaults in the other
699 -- direction. Cases which may possibly be assignments but are not known to
700 -- be may return True from May_Be_Lvalue, but False from this function.
702 function May_Be_Lvalue (N : Node_Id) return Boolean;
703 -- Determines if N could be an lvalue (e.g. an assignment left hand side).
704 -- An lvalue is defined as any expression which appears in a context where
705 -- a name is required by the syntax, and the identity, rather than merely
706 -- the value of the node is needed (for example, the prefix of an Access
707 -- attribute is in this category). Note that, as implied by the name, this
708 -- test is conservative. If it cannot be sure that N is NOT an lvalue, then
709 -- it returns True. It tries hard to get the answer right, but it is hard
710 -- to guarantee this in all cases. Note that it is more possible to give
711 -- correct answer if the tree is fully analyzed.
713 function New_External_Entity
714 (Kind : Entity_Kind;
715 Scope_Id : Entity_Id;
716 Sloc_Value : Source_Ptr;
717 Related_Id : Entity_Id;
718 Suffix : Character;
719 Suffix_Index : Nat := 0;
720 Prefix : Character := ' ') return Entity_Id;
721 -- This function creates an N_Defining_Identifier node for an internal
722 -- created entity, such as an implicit type or subtype, or a record
723 -- initialization procedure. The entity name is constructed with a call
724 -- to New_External_Name (Related_Id, Suffix, Suffix_Index, Prefix), so
725 -- that the generated name may be referenced as a public entry, and the
726 -- Is_Public flag is set if needed (using Set_Public_Status). If the
727 -- entity is for a type or subtype, the size/align fields are initialized
728 -- to unknown (Uint_0).
730 function New_Internal_Entity
731 (Kind : Entity_Kind;
732 Scope_Id : Entity_Id;
733 Sloc_Value : Source_Ptr;
734 Id_Char : Character) return Entity_Id;
735 -- This function is similar to New_External_Entity, except that the
736 -- name is constructed by New_Internal_Name (Id_Char). This is used
737 -- when the resulting entity does not have to be referenced as a
738 -- public entity (and in this case Is_Public is not set).
740 procedure Next_Actual (Actual_Id : in out Node_Id);
741 pragma Inline (Next_Actual);
742 -- Next_Actual (N) is equivalent to N := Next_Actual (N)
744 function Next_Actual (Actual_Id : Node_Id) return Node_Id;
745 -- Find next actual parameter in declaration order. As described for
746 -- First_Actual, this is the next actual in the declaration order, not
747 -- the call order, so this does not correspond to simply taking the
748 -- next entry of the Parameter_Associations list. The argument is an
749 -- actual previously returned by a call to First_Actual or Next_Actual.
750 -- Note that the result produced is always an expression, not a parameter
751 -- assciation node, even if named notation was used.
753 procedure Normalize_Actuals
754 (N : Node_Id;
755 S : Entity_Id;
756 Report : Boolean;
757 Success : out Boolean);
758 -- Reorders lists of actuals according to names of formals, value returned
759 -- in Success indicates sucess of reordering. For more details, see body.
760 -- Errors are reported only if Report is set to True.
762 procedure Note_Possible_Modification (N : Node_Id);
763 -- This routine is called if the sub-expression N maybe the target of
764 -- an assignment (e.g. it is the left side of an assignment, used as
765 -- an out parameters, or used as prefixes of access attributes). It
766 -- sets May_Be_Modified in the associated entity if there is one,
767 -- taking into account the rule that in the case of renamed objects,
768 -- it is the flag in the renamed object that must be set.
770 function Object_Access_Level (Obj : Node_Id) return Uint;
771 -- Return the accessibility level of the view of the object Obj.
772 -- For convenience, qualified expressions applied to object names
773 -- are also allowed as actuals for this function.
775 function Overrides_Synchronized_Primitive
776 (Def_Id : Entity_Id;
777 First_Hom : Entity_Id;
778 Ifaces_List : Elist_Id;
779 In_Scope : Boolean := True) return Entity_Id;
780 -- Determine whether entry or subprogram Def_Id overrides a primitive
781 -- operation that belongs to one of the interfaces in Ifaces_List. A
782 -- specific homonym chain can be specified by setting First_Hom. Flag
783 -- In_Scope is used to designate whether the entry or subprogram was
784 -- declared inside the scope of the synchronized type or after. Return
785 -- the overriden entity or Empty.
787 function Private_Component (Type_Id : Entity_Id) return Entity_Id;
788 -- Returns some private component (if any) of the given Type_Id.
789 -- Used to enforce the rules on visibility of operations on composite
790 -- types, that depend on the full view of the component type. For a
791 -- record type there may be several such components, we just return
792 -- the first one.
794 procedure Process_End_Label
795 (N : Node_Id;
796 Typ : Character;
797 Ent : Entity_Id);
798 -- N is a node whose End_Label is to be processed, generating all
799 -- appropriate cross-reference entries, and performing style checks
800 -- for any identifier references in the end label. Typ is either
801 -- 'e' or 't indicating the type of the cross-reference entity
802 -- (e for spec, t for body, see Lib.Xref spec for details). The
803 -- parameter Ent gives the entity to which the End_Label refers,
804 -- and to which cross-references are to be generated.
806 function Real_Convert (S : String) return Node_Id;
807 -- S is a possibly signed syntactically valid real literal. The result
808 -- returned is an N_Real_Literal node representing the literal value.
810 function Rep_To_Pos_Flag (E : Entity_Id; Loc : Source_Ptr) return Node_Id;
811 -- This is used to construct the second argument in a call to Rep_To_Pos
812 -- which is Standard_True if range checks are enabled (E is an entity to
813 -- which the Range_Checks_Suppressed test is applied), and Standard_False
814 -- if range checks are suppressed. Loc is the location for the node that
815 -- is returned (which is a New_Occurrence of the appropriate entity).
817 -- Note: one might think that it would be fine to always use True and
818 -- to ignore the suppress in this case, but it is generally better to
819 -- believe a request to suppress exceptions if possible, and further
820 -- more there is at least one case in the generated code (the code for
821 -- array assignment in a loop) that depends on this suppression.
823 procedure Require_Entity (N : Node_Id);
824 -- N is a node which should have an entity value if it is an entity name.
825 -- If not, then check if there were previous errors. If so, just fill
826 -- in with Any_Id and ignore. Otherwise signal a program error exception.
827 -- This is used as a defense mechanism against ill-formed trees caused by
828 -- previous errors (particularly in -gnatq mode).
830 function Requires_Transient_Scope (Id : Entity_Id) return Boolean;
831 -- E is a type entity. The result is True when temporaries of this
832 -- type need to be wrapped in a transient scope to be reclaimed
833 -- properly when a secondary stack is in use. Examples of types
834 -- requiring such wrapping are controlled types and variable-sized
835 -- types including unconstrained arrays
837 procedure Reset_Analyzed_Flags (N : Node_Id);
838 -- Reset the Analyzed flags in all nodes of the tree whose root is N
840 function Safe_To_Capture_Value
841 (N : Node_Id;
842 Ent : Entity_Id;
843 Cond : Boolean := False) return Boolean;
844 -- The caller is interested in capturing a value (either the current value,
845 -- or an indication that the value is non-null) for the given entity Ent.
846 -- This value can only be captured if sequential execution semantics can be
847 -- properly guaranteed so that a subsequent reference will indeed be sure
848 -- that this current value indication is correct. The node N is the
849 -- construct which resulted in the possible capture of the value (this
850 -- is used to check if we are in a conditional).
852 -- Cond is used to skip the test for being inside a conditional. It is used
853 -- in the case of capturing values from if/while tests, which already do a
854 -- proper job of handling scoping issues without this help.
856 -- The only entities whose values can be captured are OUT and IN OUT formal
857 -- parameters, and variables unless Cond is True, in which case we also
858 -- allow IN formals, loop parameters and constants, where we cannot ever
859 -- capture actual value information, but we can capture conditional tests.
861 function Same_Name (N1, N2 : Node_Id) return Boolean;
862 -- Determine if two (possibly expanded) names are the same name
864 function Same_Type (T1, T2 : Entity_Id) return Boolean;
865 -- Determines if T1 and T2 represent exactly the same type. Two types
866 -- are the same if they are identical, or if one is an unconstrained
867 -- subtype of the other, or they are both common subtypes of the same
868 -- type with identical constraints. The result returned is conservative.
869 -- It is True if the types are known to be the same, but a result of
870 -- False is indecisive (e.g. the compiler may not be able to tell that
871 -- two constraints are identical).
873 function Scope_Within_Or_Same (Scope1, Scope2 : Entity_Id) return Boolean;
874 -- Determines if the entity Scope1 is the same as Scope2, or if it is
875 -- inside it, where both entities represent scopes. Note that scopes
876 -- are only partially ordered, so Scope_Within_Or_Same (A,B) and
877 -- Scope_Within_Or_Same (B,A) can both be False for a given pair A,B.
879 function Scope_Within (Scope1, Scope2 : Entity_Id) return Boolean;
880 -- Like Scope_Within_Or_Same, except that this function returns
881 -- False in the case where Scope1 and Scope2 are the same scope.
883 procedure Set_Current_Entity (E : Entity_Id);
884 -- Establish the entity E as the currently visible definition of its
885 -- associated name (i.e. the Node_Id associated with its name)
887 procedure Set_Entity_With_Style_Check (N : Node_Id; Val : Entity_Id);
888 -- This procedure has the same calling sequence as Set_Entity, but
889 -- if Style_Check is set, then it calls a style checking routine which
890 -- can check identifier spelling style.
892 procedure Set_Name_Entity_Id (Id : Name_Id; Val : Entity_Id);
893 -- Sets the Entity_Id value associated with the given name, which is the
894 -- Id of the innermost visible entity with the given name. See the body
895 -- of package Sem_Ch8 for further details on the handling of visibility.
897 procedure Set_Next_Actual (Ass1_Id : Node_Id; Ass2_Id : Node_Id);
898 -- The arguments may be parameter associations, whose descendants
899 -- are the optional formal name and the actual parameter. Positional
900 -- parameters are already members of a list, and do not need to be
901 -- chained separately. See also First_Actual and Next_Actual.
903 procedure Set_Public_Status (Id : Entity_Id);
904 -- If an entity (visible or otherwise) is defined in a library
905 -- package, or a package that is itself public, then this subprogram
906 -- labels the entity public as well.
908 procedure Set_Scope_Is_Transient (V : Boolean := True);
909 -- Set the flag Is_Transient of the current scope
911 procedure Set_Size_Info (T1, T2 : Entity_Id);
912 -- Copies the Esize field and Has_Biased_Representation flag from sub(type)
913 -- entity T2 to (sub)type entity T1. Also copies the Is_Unsigned_Type flag
914 -- in the fixed-point and discrete cases, and also copies the alignment
915 -- value from T2 to T1. It does NOT copy the RM_Size field, which must be
916 -- separately set if this is required to be copied also.
918 function Scope_Is_Transient return Boolean;
919 -- True if the current scope is transient
921 function Static_Integer (N : Node_Id) return Uint;
922 -- This function analyzes the given expression node and then resolves it
923 -- as any integer type. If the result is static, then the value of the
924 -- universal expression is returned, otherwise an error message is output
925 -- and a value of No_Uint is returned.
927 function Statically_Different (E1, E2 : Node_Id) return Boolean;
928 -- Return True if it can be statically determined that the Expressions
929 -- E1 and E2 refer to different objects
931 function Subprogram_Access_Level (Subp : Entity_Id) return Uint;
932 -- Return the accessibility level of the view denoted by Subp
934 procedure Trace_Scope (N : Node_Id; E : Entity_Id; Msg : String);
935 -- Print debugging information on entry to each unit being analyzed
937 procedure Transfer_Entities (From : Entity_Id; To : Entity_Id);
938 -- Move a list of entities from one scope to another, and recompute
939 -- Is_Public based upon the new scope.
941 function Type_Access_Level (Typ : Entity_Id) return Uint;
942 -- Return the accessibility level of Typ
944 function Unit_Declaration_Node (Unit_Id : Entity_Id) return Node_Id;
945 -- Unit_Id is the simple name of a program unit, this function returns the
946 -- corresponding xxx_Declaration node for the entity. Also applies to the
947 -- body entities for subprograms, tasks and protected units, in which case
948 -- it returns the subprogram, task or protected body node for it. The unit
949 -- may be a child unit with any number of ancestors.
951 function Universal_Interpretation (Opnd : Node_Id) return Entity_Id;
952 -- Yields universal_Integer or Universal_Real if this is a candidate
954 function Unqualify (Expr : Node_Id) return Node_Id;
955 -- Removes any qualifications from Expr. For example, for T1'(T2'(X)),
956 -- this returns X. If Expr is not a qualified expression, returns Expr.
958 function Within_Init_Proc return Boolean;
959 -- Determines if Current_Scope is within an init proc
961 procedure Wrong_Type (Expr : Node_Id; Expected_Type : Entity_Id);
962 -- Output error message for incorrectly typed expression. Expr is the
963 -- node for the incorrectly typed construct (Etype (Expr) is the type
964 -- found), and Expected_Type is the entity for the expected type. Note
965 -- that Expr does not have to be a subexpression, anything with an
966 -- Etype field may be used.
968 private
969 pragma Inline (Current_Entity);
970 pragma Inline (Get_Name_Entity_Id);
971 pragma Inline (Is_False);
972 pragma Inline (Is_Statement);
973 pragma Inline (Is_True);
974 pragma Inline (Set_Current_Entity);
975 pragma Inline (Set_Name_Entity_Id);
976 pragma Inline (Set_Size_Info);
977 pragma Inline (Unqualify);
979 end Sem_Util;