1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2005, 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 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
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
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
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
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_Discriminal_Subtype_Of_Component
91 (T
: Entity_Id
) return Node_Id
;
92 -- Determine whether a record component has a type that depends on
93 -- discriminants, and build actual subtype for it if so.
95 procedure Build_Elaboration_Entity
(N
: Node_Id
; Spec_Id
: Entity_Id
);
96 -- Given a compilation unit node N, allocate an elaboration boolean for
97 -- the compilation unit, and install it in the Elaboration_Entity field
98 -- of Spec_Id, the entity for the compilation unit.
100 function Cannot_Raise_Constraint_Error
(Expr
: Node_Id
) return Boolean;
101 -- Returns True if the expression cannot possibly raise Constraint_Error.
102 -- The response is conservative in the sense that a result of False does
103 -- not necessarily mean that CE could be raised, but a response of True
104 -- means that for sure CE cannot be raised.
106 procedure Check_Fully_Declared
(T
: Entity_Id
; N
: Node_Id
);
107 -- Verify that the full declaration of type T has been seen. If not,
108 -- place error message on node N. Used in object declarations, type
109 -- conversions, qualified expressions.
111 procedure Check_Potentially_Blocking_Operation
(N
: Node_Id
);
112 -- N is one of the statement forms that is a potentially blocking
113 -- operation. If it appears within a protected action, emit warning.
115 procedure Check_VMS
(Construct
: Node_Id
);
116 -- Check that this the target is OpenVMS, and if so, return with
117 -- no effect, otherwise post an error noting this can only be used
118 -- with OpenVMS ports. The argument is the construct in question
119 -- and is used to post the error message.
121 function Collect_Primitive_Operations
(T
: Entity_Id
) return Elist_Id
;
122 -- Called upon type derivation and extension. We scan the declarative
123 -- part in which the type appears, and collect subprograms that have
124 -- one subsidiary subtype of the type. These subprograms can only
125 -- appear after the type itself.
127 function Compile_Time_Constraint_Error
130 Ent
: Entity_Id
:= Empty
;
131 Loc
: Source_Ptr
:= No_Location
;
132 Warn
: Boolean := False) return Node_Id
;
133 -- Subsidiary to Apply_Compile_Time_Constraint_Error and Checks routines.
134 -- Does not modify any nodes, but generates a warning (or error) message.
135 -- For convenience, the function always returns its first argument. The
136 -- message is a warning if the message ends with ?, or we are operating
137 -- in Ada 83 mode, or if the Warn parameter is set to True.
139 procedure Conditional_Delay
(New_Ent
, Old_Ent
: Entity_Id
);
140 -- Sets the Has_Delayed_Freeze flag of New if the Delayed_Freeze flag
141 -- of Old is set and Old has no yet been Frozen (i.e. Is_Frozen is false);
143 function Current_Entity
(N
: Node_Id
) return Entity_Id
;
144 -- Find the currently visible definition for a given identifier, that is to
145 -- say the first entry in the visibility chain for the Chars of N.
147 function Current_Entity_In_Scope
(N
: Node_Id
) return Entity_Id
;
148 -- Find whether there is a previous definition for identifier N in the
149 -- current scope. Because declarations for a scope are not necessarily
150 -- contiguous (e.g. for packages) the first entry on the visibility chain
151 -- for N is not necessarily in the current scope.
153 function Current_Scope
return Entity_Id
;
154 -- Get entity representing current scope
156 function Current_Subprogram
return Entity_Id
;
157 -- Returns current enclosing subprogram. If Current_Scope is a subprogram,
158 -- then that is what is returned, otherwise the Enclosing_Subprogram of
159 -- the Current_Scope is returned. The returned value is Empty if this
160 -- is called from a library package which is not within any subprogram.
162 function Defining_Entity
(N
: Node_Id
) return Entity_Id
;
163 -- Given a declaration N, returns the associated defining entity. If
164 -- the declaration has a specification, the entity is obtained from
165 -- the specification. If the declaration has a defining unit name,
166 -- then the defining entity is obtained from the defining unit name
167 -- ignoring any child unit prefixes.
169 function Denotes_Discriminant
171 Check_Protected
: Boolean := False) return Boolean;
172 -- Returns True if node N is an Entity_Name node for a discriminant.
173 -- If the flag Check_Protected is true, function also returns true
174 -- when N denotes the discriminal of the discriminant of a protected
175 -- type. This is necessary to disable some optimizations on private
176 -- components of protected types.
178 function Depends_On_Discriminant
(N
: Node_Id
) return Boolean;
179 -- Returns True if N denotes a discriminant or if N is a range, a subtype
180 -- indication or a scalar subtype where one of the bounds is a
183 function Designate_Same_Unit
185 Name2
: Node_Id
) return Boolean;
186 -- Return true if Name1 and Name2 designate the same unit name;
187 -- each of these names is supposed to be a selected component name,
188 -- an expanded name, a defining program unit name or an identifier
190 function Enclosing_Generic_Body
191 (E
: Entity_Id
) return Node_Id
;
192 -- Returns the Node_Id associated with the innermost enclosing
193 -- generic body, if any. If none, then returns Empty.
195 function Enclosing_Lib_Unit_Entity
return Entity_Id
;
196 -- Returns the entity of enclosing N_Compilation_Unit Node which is the
197 -- root of the current scope (which must not be Standard_Standard, and
198 -- the caller is responsible for ensuring this condition).
200 function Enclosing_Lib_Unit_Node
(N
: Node_Id
) return Node_Id
;
201 -- Returns the enclosing N_Compilation_Unit Node that is the root
202 -- of a subtree containing N.
204 function Enclosing_Subprogram
(E
: Entity_Id
) return Entity_Id
;
205 -- Utility function to return the Ada entity of the subprogram enclosing
206 -- the entity E, if any. Returns Empty if no enclosing subprogram.
208 procedure Ensure_Freeze_Node
(E
: Entity_Id
);
209 -- Make sure a freeze node is allocated for entity E. If necessary,
210 -- build and initialize a new freeze node and set Has_Delayed_Freeze
211 -- true for entity E.
213 procedure Enter_Name
(Def_Id
: Node_Id
);
214 -- Insert new name in symbol table of current scope with check for
215 -- duplications (error message is issued if a conflict is found)
216 -- Note: Enter_Name is not used for overloadable entities, instead
217 -- these are entered using Sem_Ch6.Enter_Overloadable_Entity.
219 procedure Explain_Limited_Type
(T
: Entity_Id
; N
: Node_Id
);
220 -- This procedure is called after issuing a message complaining
221 -- about an inappropriate use of limited type T. If useful, it
222 -- adds additional continuation lines to the message explaining
223 -- why type T is limited. Messages are placed at node N.
225 function Find_Corresponding_Discriminant
227 Typ
: Entity_Id
) return Entity_Id
;
228 -- Because discriminants may have different names in a generic unit
229 -- and in an instance, they are resolved positionally when possible.
230 -- A reference to a discriminant carries the discriminant that it
231 -- denotes when analyzed. Subsequent uses of this id on a different
232 -- type denote the discriminant at the same position in this new type.
234 function First_Actual
(Node
: Node_Id
) return Node_Id
;
235 -- Node is an N_Function_Call or N_Procedure_Call_Statement node. The
236 -- result returned is the first actual parameter in declaration order
237 -- (not the order of parameters as they appeared in the source, which
238 -- can be quite different as a result of the use of named parameters).
239 -- Empty is returned for a call with no parameters. The procedure for
240 -- iterating through the actuals in declaration order is to use this
241 -- function to find the first actual, and then use Next_Actual to obtain
242 -- the next actual in declaration order. Note that the value returned
243 -- is always the expression (not the N_Parameter_Association nodes
244 -- even if named association is used).
246 function Full_Qualified_Name
(E
: Entity_Id
) return String_Id
;
247 -- Generates the string literal corresponding to the E's full qualified
248 -- name in upper case. An ASCII.NUL is appended as the last character
250 function Find_Static_Alternative
(N
: Node_Id
) return Node_Id
;
251 -- N is a case statement whose expression is a compile-time value.
252 -- Determine the alternative chosen, so that the code of non-selected
253 -- alternatives, and the warnings that may apply to them, are removed.
255 procedure Gather_Components
258 Governed_By
: List_Id
;
260 Report_Errors
: out Boolean);
261 -- The purpose of this procedure is to gather the valid components in a
262 -- record type according to the values of its discriminants, in order to
263 -- validate the components of a record aggregate.
265 -- Typ is the type of the aggregate when its constrained discriminants
266 -- need to be collected, otherwise it is Empty.
268 -- Comp_List is an N_Component_List node.
270 -- Governed_By is a list of N_Component_Association nodes, where each
271 -- choice list contains the name of a discriminant and the expression
272 -- field gives its value. The values of the discriminants governing
273 -- the (possibly nested) variant parts in Comp_List are found in this
274 -- Component_Association List.
276 -- Into is the list where the valid components are appended. Note that
277 -- Into need not be an Empty list. If it's not, components are attached
280 -- Report_Errors is set to True if the values of the discriminants are
283 -- This procedure is also used when building a record subtype. If the
284 -- discriminant constraint of the subtype is static, the components of the
285 -- subtype are only those of the variants selected by the values of the
286 -- discriminants. Otherwise all components of the parent must be included
287 -- in the subtype for semantic analysis.
289 function Get_Actual_Subtype
(N
: Node_Id
) return Entity_Id
;
290 -- Given a node for an expression, obtain the actual subtype of the
291 -- expression. In the case of a parameter where the formal is an
292 -- unconstrained array or discriminated type, this will be the
293 -- previously constructed subtype of the actual. Note that this is
294 -- not quite the "Actual Subtype" of the RM, since it is always
295 -- a constrained type, i.e. it is the subtype of the value of the
296 -- actual. The actual subtype is also returned in other cases where
297 -- it has already been constructed for an object. Otherwise the
298 -- expression type is returned unchanged, except for the case of an
299 -- unconstrained array type, where an actual subtype is created, using
300 -- Insert_Actions if necessary to insert any associated actions.
302 function Get_Actual_Subtype_If_Available
(N
: Node_Id
) return Entity_Id
;
303 -- This is like Get_Actual_Subtype, except that it never constructs an
304 -- actual subtype. If an actual subtype is already available, i.e. the
305 -- Actual_Subtype field of the corresponding entity is set, then it is
306 -- returned. Otherwise the Etype of the node is returned.
308 function Get_Default_External_Name
(E
: Node_Or_Entity_Id
) return Node_Id
;
309 -- This is used to construct the string literal node representing a
310 -- default external name, i.e. one that is constructed from the name
311 -- of an entity, or (in the case of extended DEC import/export pragmas,
312 -- an identifier provided as the external name. Letters in the name are
313 -- according to the setting of Opt.External_Name_Default_Casing.
315 function Get_Generic_Entity
(N
: Node_Id
) return Entity_Id
;
316 -- Returns the true generic entity in an instantiation. If the name in
317 -- the instantiation is a renaming, the function returns the renamed
320 procedure Get_Index_Bounds
(N
: Node_Id
; L
, H
: out Node_Id
);
321 -- This procedure assigns to L and H respectively the values of the
322 -- low and high bounds of node N, which must be a range, subtype
323 -- indication, or the name of a scalar subtype. The result in L, H
324 -- may be set to Error if there was an earlier error in the range.
326 function Get_Enum_Lit_From_Pos
329 Loc
: Source_Ptr
) return Entity_Id
;
330 -- This function obtains the E_Enumeration_Literal entity for the
331 -- specified value from the enumneration type or subtype T. The
332 -- second argument is the Pos value, which is assumed to be in range.
333 -- The third argument supplies a source location for constructed
334 -- nodes returned by this function.
336 procedure Get_Library_Unit_Name_String
(Decl_Node
: Node_Id
);
337 -- Retrieve the fully expanded name of the library unit declared by
338 -- Decl_Node into the name buffer.
340 function Get_Name_Entity_Id
(Id
: Name_Id
) return Entity_Id
;
341 -- An entity value is associated with each name in the name table. The
342 -- Get_Name_Entity_Id function fetches the Entity_Id of this entity,
343 -- which is the innermost visible entity with the given name. See the
344 -- body of Sem_Ch8 for further details on handling of entity visibility.
346 function Get_Referenced_Object
(N
: Node_Id
) return Node_Id
;
347 -- Given a node, return the renamed object if the node represents
348 -- a renamed object, otherwise return the node unchanged. The node
349 -- may represent an arbitrary expression.
351 function Get_Subprogram_Body
(E
: Entity_Id
) return Node_Id
;
352 -- Given the entity for a subprogram (E_Function or E_Procedure),
353 -- return the corresponding N_Subprogram_Body node. If the corresponding
354 -- body of the declaration is missing (as for an imported subprogram)
357 function Get_Task_Body_Procedure
(E
: Entity_Id
) return Node_Id
;
358 pragma Inline
(Get_Task_Body_Procedure
);
359 -- Given an entity for a task type or subtype, retrieves the
360 -- Task_Body_Procedure field from the corresponding task type
363 function Has_Access_Values
(T
: Entity_Id
) return Boolean;
364 -- Returns true if type or subtype T is an access type, or has a
365 -- component (at any recursive level) that is an access type. This
366 -- is a conservative predicate, if it is not known whether or not
367 -- T contains access values (happens for generic formals in some
368 -- cases), then False is returned.
370 function Has_Declarations
(N
: Node_Id
) return Boolean;
371 -- Determines if the node can have declarations
373 function Has_Discriminant_Dependent_Constraint
374 (Comp
: Entity_Id
) return Boolean;
375 -- Returns True if and only if Comp has a constrained subtype
376 -- that depends on a discriminant.
378 function Has_Infinities
(E
: Entity_Id
) return Boolean;
379 -- Determines if the range of the floating-point type E includes
380 -- infinities. Returns False if E is not a floating-point type.
382 function Has_Private_Component
(Type_Id
: Entity_Id
) return Boolean;
383 -- Check if a type has a (sub)component of a private type that has not
384 -- yet received a full declaration.
386 function Has_Stream
(T
: Entity_Id
) return Boolean;
387 -- Tests if type T is derived from Ada.Streams.Root_Stream_Type, or
388 -- in the case of a composite type, has a component for which this
389 -- predicate is True, and if so returns True. Otherwise a result of
390 -- False means that there is no Stream type in sight. For a private
391 -- type, the test is applied to the underlying type (or returns False
392 -- if there is no underlying type).
394 function Has_Tagged_Component
(Typ
: Entity_Id
) return Boolean;
395 -- Typ must be a composite type (array or record). This function is used
396 -- to check if '=' has to be expanded into a bunch component comparaisons.
398 function In_Instance
return Boolean;
399 -- Returns True if the current scope is within a generic instance
401 function In_Instance_Body
return Boolean;
402 -- Returns True if current scope is within the body of an instance, where
403 -- several semantic checks (e.g. accessibility checks) are relaxed.
405 function In_Instance_Not_Visible
return Boolean;
406 -- Returns True if current scope is with the private part or the body of
407 -- an instance. Other semantic checks are suppressed in this context.
409 function In_Instance_Visible_Part
return Boolean;
410 -- Returns True if current scope is within the visible part of a package
411 -- instance, where several additional semantic checks apply.
413 function In_Package_Body
return Boolean;
414 -- Returns True if current scope is within a package body
416 function In_Subprogram_Or_Concurrent_Unit
return Boolean;
417 -- Determines if the current scope is within a subprogram compilation
418 -- unit (inside a subprogram declaration, subprogram body, or generic
419 -- subprogram declaration) or within a task or protected body. The test
420 -- is for appearing anywhere within such a construct (that is it does not
421 -- need to be directly within).
423 function In_Visible_Part
(Scope_Id
: Entity_Id
) return Boolean;
424 -- Determine whether a declaration occurs within the visible part of a
425 -- package specification. The package must be on the scope stack, and the
426 -- corresponding private part must not.
428 procedure Insert_Explicit_Dereference
(N
: Node_Id
);
429 -- In a context that requires a composite or subprogram type and
430 -- where a prefix is an access type, rewrite the access type node
431 -- N (which is the prefix, e.g. of an indexed component) as an
432 -- explicit dereference.
434 function Is_AAMP_Float
(E
: Entity_Id
) return Boolean;
435 -- Defined for all type entities. Returns True only for the base type
436 -- of float types with AAMP format. The particular format is determined
437 -- by the Digits_Value value which is 6 for the 32-bit floating point type,
438 -- or 9 for the 48-bit type. This is not an attribute function (like
439 -- VAX_Float) in order to not use up an extra flag and to prevent
440 -- the dependency of Einfo on Targparm which would be required for a
441 -- synthesized attribute.
443 function Is_Actual_Parameter
(N
: Node_Id
) return Boolean;
444 -- Determines if N is an actual parameter in a subprogram call
446 function Is_Aliased_View
(Obj
: Node_Id
) return Boolean;
447 -- Determine if Obj is an aliased view, i.e. the name of an
448 -- object to which 'Access or 'Unchecked_Access can apply.
450 function Is_Ancestor_Package
452 E2
: Entity_Id
) return Boolean;
453 -- Determine whether package E1 is an ancestor of E2
455 function Is_Atomic_Object
(N
: Node_Id
) return Boolean;
456 -- Determines if the given node denotes an atomic object in the sense
457 -- of the legality checks described in RM C.6(12).
459 function Is_Dependent_Component_Of_Mutable_Object
460 (Object
: Node_Id
) return Boolean;
461 -- Returns True if Object is the name of a subcomponent that
462 -- depends on discriminants of a variable whose nominal subtype
463 -- is unconstrained and not indefinite, and the variable is
464 -- not aliased. Otherwise returns False. The nodes passed
465 -- to this function are assumed to denote objects.
467 function Is_Dereferenced
(N
: Node_Id
) return Boolean;
468 -- N is a subexpression node of an access type. This function returns
469 -- true if N appears as the prefix of a node that does a dereference
470 -- of the access value (selected/indexed component, explicit dereference
471 -- or a slice), and false otherwise.
473 function Is_Descendent_Of
(T1
: Entity_Id
; T2
: Entity_Id
) return Boolean;
474 -- Returns True if type T1 is a descendent of type T2, and false otherwise.
475 -- This is the RM definition, a type is a descendent of another type if it
476 -- is the same type or is derived from a descendent of the other type.
478 function Is_Descendent_Of_Address
(T1
: Entity_Id
) return Boolean;
479 -- Returns True if type T1 is a descendent of Address or its base type.
480 -- Similar to calling Is_Descendent_Of with Base_Type (RTE (RE_Address))
481 -- except that it avoids creating an unconditional dependency on System.
483 function Is_False
(U
: Uint
) return Boolean;
484 -- The argument is a Uint value which is the Boolean'Pos value of a
485 -- Boolean operand (i.e. is either 0 for False, or 1 for True). This
486 -- function simply tests if it is False (i.e. zero)
488 function Is_Fixed_Model_Number
(U
: Ureal
; T
: Entity_Id
) return Boolean;
489 -- Returns True iff the number U is a model number of the fixed-
490 -- point type T, i.e. if it is an exact multiple of Small.
492 function Is_Fully_Initialized_Type
(Typ
: Entity_Id
) return Boolean;
493 -- Typ is a type entity. This function returns true if this type is
494 -- fully initialized, meaning that an object of the type is fully
495 -- initialized. Note that initialization resulting from the use of
496 -- pragma Normalized_Scalars does not count. Note that this is only
497 -- used for the purpose of issuing warnings for objects that are
498 -- potentially referenced uninitialized. This means that the result
499 -- returned is not crucial, but probably should err on the side of
500 -- thinking things are fully initialized if it does not know.
502 function Is_Inherited_Operation
(E
: Entity_Id
) return Boolean;
503 -- E is a subprogram. Return True is E is an implicit operation inherited
504 -- by a derived type declarations.
506 function Is_Lvalue
(N
: Node_Id
) return Boolean;
507 -- Determines if N could be an lvalue (e.g. an assignment left hand side).
508 -- This determination is conservative, it must never answer False if N is
509 -- an lvalue, but it can answer True when N is not an lvalue. An lvalue is
510 -- defined as any expression which appears in a context where a name is
511 -- required by the syntax, and the identity, rather than merely the value
512 -- of the node is needed (for example, the prefix of an Access attribute
513 -- is in this category).
515 function Is_Library_Level_Entity
(E
: Entity_Id
) return Boolean;
516 -- A library-level declaration is one that is accessible from Standard,
517 -- i.e. a library unit or an entity declared in a library package.
519 function Is_Local_Variable_Reference
(Expr
: Node_Id
) return Boolean;
520 -- Determines whether Expr is a refeference to a variable or IN OUT
521 -- mode parameter of the current enclosing subprogram.
522 -- Why are OUT parameters not considered here ???
524 function Is_Object_Reference
(N
: Node_Id
) return Boolean;
525 -- Determines if the tree referenced by N represents an object. Both
526 -- variable and constant objects return True (compare Is_Variable).
528 function Is_OK_Variable_For_Out_Formal
(AV
: Node_Id
) return Boolean;
529 -- Used to test if AV is an acceptable formal for an OUT or IN OUT
530 -- formal. Note that the Is_Variable function is not quite the right
531 -- test because this is a case in which conversions whose expression
532 -- is a variable (in the Is_Variable sense) with a non-tagged type
533 -- target are considered view conversions and hence variables.
535 function Is_Partially_Initialized_Type
(Typ
: Entity_Id
) return Boolean;
536 -- Typ is a type entity. This function returns true if this type is
537 -- partly initialized, meaning that an object of the type is at least
538 -- partly initialized (in particular in the record case, that at least
539 -- one field has an initialization expression). Note that initialization
540 -- resulting from the use of pragma Normalized_Scalars does not count.
542 function Is_Potentially_Persistent_Type
(T
: Entity_Id
) return Boolean;
543 -- Determines if type T is a potentially persistent type. A potentially
544 -- persistent type is defined (recursively) as a scalar type, a non-tagged
545 -- record whose components are all of a potentially persistent type, or an
546 -- array with all static constraints whose component type is potentially
547 -- persistent. A private type is potentially persistent if the full type
548 -- is potentially persistent.
550 function Is_RCI_Pkg_Spec_Or_Body
(Cunit
: Node_Id
) return Boolean;
551 -- Return True if a compilation unit is the specification or the
552 -- body of a remote call interface package.
554 function Is_Remote_Access_To_Class_Wide_Type
(E
: Entity_Id
) return Boolean;
555 -- Return True if E is a remote access-to-class-wide-limited_private type
557 function Is_Remote_Access_To_Subprogram_Type
(E
: Entity_Id
) return Boolean;
558 -- Return True if E is a remote access to subprogram type
560 function Is_Remote_Call
(N
: Node_Id
) return Boolean;
561 -- Return True if N denotes a potentially remote call
563 function Is_Selector_Name
(N
: Node_Id
) return Boolean;
564 -- Given an N_Identifier node N, determines if it is a Selector_Name.
565 -- As described in Sinfo, Selector_Names are special because they
566 -- represent use of the N_Identifier node for a true identifer, when
567 -- normally such nodes represent a direct name.
569 function Is_Statement
(N
: Node_Id
) return Boolean;
570 -- Check if the node N is a statement node. Note that this includes
571 -- the case of procedure call statements (unlike the direct use of
572 -- the N_Statement_Other_Than_Procedure_Call subtype from Sinfo).
573 -- Note that a label is *not* a statement, and will return False.
575 function Is_Transfer
(N
: Node_Id
) return Boolean;
576 -- Returns True if the node N is a statement which is known to cause
577 -- an unconditional transfer of control at runtime, i.e. the following
578 -- statement definitely will not be executed.
580 function Is_True
(U
: Uint
) return Boolean;
581 -- The argument is a Uint value which is the Boolean'Pos value of a
582 -- Boolean operand (i.e. is either 0 for False, or 1 for True). This
583 -- function simply tests if it is True (i.e. non-zero)
585 function Is_Variable
(N
: Node_Id
) return Boolean;
586 -- Determines if the tree referenced by N represents a variable, i.e.
587 -- can appear on the left side of an assignment. There is one situation,
588 -- namely formal parameters, in which non-tagged type conversions are
589 -- also considered variables, but Is_Variable returns False for such
590 -- cases, since it has no knowledge of the context. Note that this is
591 -- the point at which Assignment_OK is checked, and True is returned
592 -- for any tree thus marked.
594 function Is_Volatile_Object
(N
: Node_Id
) return Boolean;
595 -- Determines if the given node denotes an volatile object in the sense
596 -- of the legality checks described in RM C.6(12). Note that the test
597 -- here is for something actually declared as volatile, not for an object
598 -- that gets treated as volatile (see Einfo.Treat_As_Volatile).
600 procedure Kill_Current_Values
;
601 -- This procedure is called to clear all constant indications from all
602 -- entities in the current scope and in any parent scopes if the current
603 -- scope is a block or a pacakage (and that recursion continues to the
604 -- top scope that is not a block or a package). This is used when the
605 -- sequential flow-of-control assumption is violated (occurence of a
606 -- label, head of a loop, or start of an exception handler). The effect
607 -- of the call is to clear the Constant_Value field (but we do not need
608 -- to clear the Is_True_Constant flag, since that only gets reset if
609 -- there really is an assignment somewhere in the entity scope). This
610 -- procedure also calls Kill_All_Checks, since this is a special case
611 -- of needing to forget saved values. This procedure also clears any
612 -- Is_Known_Non_Null flags in variables, constants or parameters
613 -- since these are also not known to be valid.
615 procedure Kill_Size_Check_Code
(E
: Entity_Id
);
616 -- Called when an address clause or pragma Import is applied to an
617 -- entity. If the entity is a variable or a constant, and size check
618 -- code is present, this size check code is killed, since the object
619 -- will not be allocated by the program.
621 function New_External_Entity
623 Scope_Id
: Entity_Id
;
624 Sloc_Value
: Source_Ptr
;
625 Related_Id
: Entity_Id
;
627 Suffix_Index
: Nat
:= 0;
628 Prefix
: Character := ' ') return Entity_Id
;
629 -- This function creates an N_Defining_Identifier node for an internal
630 -- created entity, such as an implicit type or subtype, or a record
631 -- initialization procedure. The entity name is constructed with a call
632 -- to New_External_Name (Related_Id, Suffix, Suffix_Index, Prefix), so
633 -- that the generated name may be referenced as a public entry, and the
634 -- Is_Public flag is set if needed (using Set_Public_Status). If the
635 -- entity is for a type or subtype, the size/align fields are initialized
636 -- to unknown (Uint_0).
638 function New_Internal_Entity
640 Scope_Id
: Entity_Id
;
641 Sloc_Value
: Source_Ptr
;
642 Id_Char
: Character) return Entity_Id
;
643 -- This function is similar to New_External_Entity, except that the
644 -- name is constructed by New_Internal_Name (Id_Char). This is used
645 -- when the resulting entity does not have to be referenced as a
646 -- public entity (and in this case Is_Public is not set).
648 procedure Next_Actual
(Actual_Id
: in out Node_Id
);
649 pragma Inline
(Next_Actual
);
650 -- Next_Actual (N) is equivalent to N := Next_Actual (N)
652 function Next_Actual
(Actual_Id
: Node_Id
) return Node_Id
;
653 -- Find next actual parameter in declaration order. As described for
654 -- First_Actual, this is the next actual in the declaration order, not
655 -- the call order, so this does not correspond to simply taking the
656 -- next entry of the Parameter_Associations list. The argument is an
657 -- actual previously returned by a call to First_Actual or Next_Actual.
658 -- Note that the result produced is always an expression, not a parameter
659 -- assciation node, even if named notation was used.
661 procedure Normalize_Actuals
665 Success
: out Boolean);
666 -- Reorders lists of actuals according to names of formals, value returned
667 -- in Success indicates sucess of reordering. For more details, see body.
668 -- Errors are reported only if Report is set to True.
670 procedure Note_Possible_Modification
(N
: Node_Id
);
671 -- This routine is called if the sub-expression N maybe the target of
672 -- an assignment (e.g. it is the left side of an assignment, used as
673 -- an out parameters, or used as prefixes of access attributes). It
674 -- sets May_Be_Modified in the associated entity if there is one,
675 -- taking into account the rule that in the case of renamed objects,
676 -- it is the flag in the renamed object that must be set.
678 function Object_Access_Level
(Obj
: Node_Id
) return Uint
;
679 -- Return the accessibility level of the view of the object Obj.
680 -- For convenience, qualified expressions applied to object names
681 -- are also allowed as actuals for this function.
683 function Private_Component
(Type_Id
: Entity_Id
) return Entity_Id
;
684 -- Returns some private component (if any) of the given Type_Id.
685 -- Used to enforce the rules on visibility of operations on composite
686 -- types, that depend on the full view of the component type. For a
687 -- record type there may be several such components, we just return
690 procedure Process_End_Label
694 -- N is a node whose End_Label is to be processed, generating all
695 -- appropriate cross-reference entries, and performing style checks
696 -- for any identifier references in the end label. Typ is either
697 -- 'e' or 't indicating the type of the cross-reference entity
698 -- (e for spec, t for body, see Lib.Xref spec for details). The
699 -- parameter Ent gives the entity to which the End_Label refers,
700 -- and to which cross-references are to be generated.
702 function Real_Convert
(S
: String) return Node_Id
;
703 -- S is a possibly signed syntactically valid real literal. The result
704 -- returned is an N_Real_Literal node representing the literal value.
706 function Rep_To_Pos_Flag
(E
: Entity_Id
; Loc
: Source_Ptr
) return Node_Id
;
707 -- This is used to construct the second argument in a call to Rep_To_Pos
708 -- which is Standard_True if range checks are enabled (E is an entity to
709 -- which the Range_Checks_Suppressed test is applied), and Standard_False
710 -- if range checks are suppressed. Loc is the location for the node that
711 -- is returned (which is a New_Occurrence of the appropriate entity).
713 -- Note: one might think that it would be fine to always use True and
714 -- to ignore the suppress in this case, but it is generally better to
715 -- believe a request to suppress exceptions if possible, and further
716 -- more there is at least one case in the generated code (the code for
717 -- array assignment in a loop) that depends on this suppression.
719 procedure Require_Entity
(N
: Node_Id
);
720 -- N is a node which should have an entity value if it is an entity name.
721 -- If not, then check if there were previous errors. If so, just fill
722 -- in with Any_Id and ignore. Otherwise signal a program error exception.
723 -- This is used as a defense mechanism against ill-formed trees caused by
724 -- previous errors (particularly in -gnatq mode).
726 function Requires_Transient_Scope
(Id
: Entity_Id
) return Boolean;
727 -- E is a type entity. The result is True when temporaries of this
728 -- type need to be wrapped in a transient scope to be reclaimed
729 -- properly when a secondary stack is in use. Examples of types
730 -- requiring such wrapping are controlled types and variable-sized
731 -- types including unconstrained arrays
733 procedure Reset_Analyzed_Flags
(N
: Node_Id
);
734 -- Reset the Analyzed flags in all nodes of the tree whose root is N
736 function Safe_To_Capture_Value
740 -- The caller is interested in capturing a value (either the current
741 -- value, or an indication that the value is non-null) for the given
742 -- entity Ent. This value can only be captured if sequential execution
743 -- semantics can be properly guaranteed so that a subsequent reference
744 -- will indeed be sure that this current value indication is correct.
745 -- The node N is the construct which resulted in the possible capture
746 -- of the value (this is used to check if we are in a conditional).
748 function Same_Name
(N1
, N2
: Node_Id
) return Boolean;
749 -- Determine if two (possibly expanded) names are the same name
751 function Same_Type
(T1
, T2
: Entity_Id
) return Boolean;
752 -- Determines if T1 and T2 represent exactly the same type. Two types
753 -- are the same if they are identical, or if one is an unconstrained
754 -- subtype of the other, or they are both common subtypes of the same
755 -- type with identical constraints. The result returned is conservative.
756 -- It is True if the types are known to be the same, but a result of
757 -- False is indecisive (e.g. the compiler may not be able to tell that
758 -- two constraints are identical).
760 function Scope_Within_Or_Same
(Scope1
, Scope2
: Entity_Id
) return Boolean;
761 -- Determines if the entity Scope1 is the same as Scope2, or if it is
762 -- inside it, where both entities represent scopes. Note that scopes
763 -- are only partially ordered, so Scope_Within_Or_Same (A,B) and
764 -- Scope_Within_Or_Same (B,A) can both be False for a given pair A,B.
766 function Scope_Within
(Scope1
, Scope2
: Entity_Id
) return Boolean;
767 -- Like Scope_Within_Or_Same, except that this function returns
768 -- False in the case where Scope1 and Scope2 are the same scope.
770 procedure Set_Current_Entity
(E
: Entity_Id
);
771 -- Establish the entity E as the currently visible definition of its
772 -- associated name (i.e. the Node_Id associated with its name)
774 procedure Set_Entity_With_Style_Check
(N
: Node_Id
; Val
: Entity_Id
);
775 -- This procedure has the same calling sequence as Set_Entity, but
776 -- if Style_Check is set, then it calls a style checking routine which
777 -- can check identifier spelling style.
779 procedure Set_Name_Entity_Id
(Id
: Name_Id
; Val
: Entity_Id
);
780 -- Sets the Entity_Id value associated with the given name, which is the
781 -- Id of the innermost visible entity with the given name. See the body
782 -- of package Sem_Ch8 for further details on the handling of visibility.
784 procedure Set_Next_Actual
(Ass1_Id
: Node_Id
; Ass2_Id
: Node_Id
);
785 -- The arguments may be parameter associations, whose descendants
786 -- are the optional formal name and the actual parameter. Positional
787 -- parameters are already members of a list, and do not need to be
788 -- chained separately. See also First_Actual and Next_Actual.
790 procedure Set_Public_Status
(Id
: Entity_Id
);
791 -- If an entity (visible or otherwise) is defined in a library
792 -- package, or a package that is itself public, then this subprogram
793 -- labels the entity public as well.
795 procedure Set_Scope_Is_Transient
(V
: Boolean := True);
796 -- Set the flag Is_Transient of the current scope
798 procedure Set_Size_Info
(T1
, T2
: Entity_Id
);
799 -- Copies the Esize field and Has_Biased_Representation flag from sub(type)
800 -- entity T2 to (sub)type entity T1. Also copies the Is_Unsigned_Type flag
801 -- in the fixed-point and discrete cases, and also copies the alignment
802 -- value from T2 to T1. It does NOT copy the RM_Size field, which must be
803 -- separately set if this is required to be copied also.
805 function Scope_Is_Transient
return Boolean;
806 -- True if the current scope is transient
808 function Static_Integer
(N
: Node_Id
) return Uint
;
809 -- This function analyzes the given expression node and then resolves it
810 -- as any integer type. If the result is static, then the value of the
811 -- universal expression is returned, otherwise an error message is output
812 -- and a value of No_Uint is returned.
814 function Statically_Different
(E1
, E2
: Node_Id
) return Boolean;
815 -- Return True if it can be statically determined that the Expressions
816 -- E1 and E2 refer to different objects
818 function Subprogram_Access_Level
(Subp
: Entity_Id
) return Uint
;
819 -- Return the accessibility level of the view denoted by Subp
821 procedure Trace_Scope
(N
: Node_Id
; E
: Entity_Id
; Msg
: String);
822 -- Print debugging information on entry to each unit being analyzed
824 procedure Transfer_Entities
(From
: Entity_Id
; To
: Entity_Id
);
825 -- Move a list of entities from one scope to another, and recompute
826 -- Is_Public based upon the new scope.
828 function Type_Access_Level
(Typ
: Entity_Id
) return Uint
;
829 -- Return the accessibility level of Typ
831 function Unit_Declaration_Node
(Unit_Id
: Entity_Id
) return Node_Id
;
832 -- Unit_Id is the simple name of a program unit, this function returns the
833 -- corresponding xxx_Declaration node for the entity. Also applies to the
834 -- body entities for subprograms, tasks and protected units, in which case
835 -- it returns the subprogram, task or protected body node for it. The unit
836 -- may be a child unit with any number of ancestors.
838 function Universal_Interpretation
(Opnd
: Node_Id
) return Entity_Id
;
839 -- Yields universal_Integer or Universal_Real if this is a candidate
841 function Within_Init_Proc
return Boolean;
842 -- Determines if Current_Scope is within an init proc
844 procedure Wrong_Type
(Expr
: Node_Id
; Expected_Type
: Entity_Id
);
845 -- Output error message for incorrectly typed expression. Expr is the
846 -- node for the incorrectly typed construct (Etype (Expr) is the type
847 -- found), and Expected_Type is the entity for the expected type. Note
848 -- that Expr does not have to be a subexpression, anything with an
849 -- Etype field may be used.
852 pragma Inline
(Current_Entity
);
853 pragma Inline
(Get_Name_Entity_Id
);
854 pragma Inline
(Is_False
);
855 pragma Inline
(Is_Statement
);
856 pragma Inline
(Is_True
);
857 pragma Inline
(Set_Current_Entity
);
858 pragma Inline
(Set_Name_Entity_Id
);
859 pragma Inline
(Set_Size_Info
);