| blob | 2892916c75708b4687f7d7b2dea3f810035c9378 |
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) 1992-2014, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
26 -- Package containing utility procedures used throughout the semantics
40 -- Given a type that implements interfaces look for its associated
41 -- definition node and return its list of interfaces.
44 -- Add A to the list of access types to process when expanding the
45 -- freeze node of E.
48 -- Given a block statement N, generate an internal E_Block label and make
49 -- it the identifier of the block. Id denotes the generated entity. If the
50 -- block already has an identifier, Id returns the entity of its label.
53 -- Add pragma Prag to the contract of an entry, a package [body], a
54 -- subprogram [body] or variable denoted by Id. The following are valid
55 -- pragmas:
56 -- Abstract_States
57 -- Async_Readers
58 -- Async_Writers
59 -- Contract_Cases
60 -- Depends
61 -- Effective_Reads
62 -- Effective_Writes
63 -- Global
64 -- Initial_Condition
65 -- Initializes
66 -- Part_Of
67 -- Postcondition
68 -- Precondition
69 -- Refined_Depends
70 -- Refined_Global
71 -- Refined_Post
72 -- Refined_States
73 -- Test_Case
76 -- These procedures adds a declaration N at the library level, to be
77 -- elaborated before any other code in the unit. It is used for example
78 -- for the entity that marks whether a unit has been elaborated. The
79 -- declaration is added to the Declarations list of the Aux_Decls_Node
80 -- for the current unit. The declarations are added in the current scope,
81 -- so the caller should push a new scope as required before the call.
84 -- Given two types, returns True if we are in Allow_Integer_Address mode
85 -- and one of the types is (a descendent of) System.Address (and this type
86 -- is private), and the other type is any integer type.
91 -- Returns True if the value of V is the word size or an addressable factor
92 -- of the word size (typically 8, 16, 32 or 64).
94 procedure Aggregate_Constraint_Checks
97 -- Checks expression Exp against subtype Check_Typ. If Exp is an aggregate
98 -- and Check_Typ a constrained record type with discriminants, we generate
99 -- the appropriate discriminant checks. If Exp is an array aggregate then
100 -- emit the appropriate length checks. If Exp is a scalar type, or a string
101 -- literal, Exp is changed into Check_Typ'(Exp) to ensure that range checks
102 -- are performed at run time. Also used for expressions in the argument of
103 -- 'Update, which shares some of the features of an aggregate.
106 -- If the alignment of the type or object E is currently known to the
107 -- compiler, then this function returns the alignment value in bits.
108 -- Otherwise Uint_0 is returned, indicating that the alignment of the
109 -- entity is not yet known to the compiler.
112 -- If the parent of the operation is declared in the visible part of
113 -- the current scope, the inherited operation is visible even though the
114 -- derived type that inherits the operation may be completed in the private
115 -- part of the current package.
117 procedure Apply_Compile_Time_Constraint_Error
126 -- N is a subexpression which will raise constraint error when evaluated
127 -- at runtime. Msg is a message that explains the reason for raising the
128 -- exception. The last character is ? if the message is always a warning,
129 -- even in Ada 95, and is not a ? if the message represents an illegality
130 -- (because of violation of static expression rules) in Ada 95 (but not
131 -- in Ada 83). Typically this routine posts all messages at the Sloc of
132 -- node N. However, if Loc /= No_Location, Loc is the Sloc used to output
133 -- the message. After posting the appropriate message, and if the flag
134 -- Rep is set, this routine replaces the expression with an appropriate
135 -- N_Raise_Constraint_Error node using the given Reason code. This node
136 -- is then marked as being static if the original node is static, but
137 -- sets the flag Raises_Constraint_Error, preventing further evaluation.
138 -- The error message may contain a } or & insertion character. This
139 -- normally references Etype (N), unless the Ent argument is given
140 -- explicitly, in which case it is used instead. The type of the raise
141 -- node that is built is normally Etype (N), but if the Typ parameter
142 -- is present, this is used instead. Warn is normally False. If it is
143 -- True then the message is treated as a warning even though it does
144 -- not end with a ? (this is used when the caller wants to parameterize
145 -- whether an error or warning is given).
148 -- Given the entity of an abstract state or a variable, determine whether
149 -- Id is subject to external property Async_Readers and if it is, the
150 -- related expression evaluates to True.
153 -- Given the entity of an abstract state or a variable, determine whether
154 -- Id is subject to external property Async_Writers and if it is, the
155 -- related expression evaluates to True.
158 -- If at the point of declaration an array type has a private or limited
159 -- component, several array operations are not avaiable on the type, and
160 -- the array type is flagged accordingly. If in the immediate scope of
161 -- the array type the component becomes non-private or non-limited, these
162 -- operations become avaiable. This can happen if the scopes of both types
163 -- are open, and the scope of the array is not outside the scope of the
164 -- component.
166 procedure Bad_Attribute
170 -- Called when node N is expected to contain a valid attribute name, and
171 -- Nam is found instead. If Warn is set True this is a warning, else this
172 -- is an error.
174 procedure Bad_Predicated_Subtype_Use
179 -- This is called when Typ, a predicated subtype, is used in a context
180 -- which does not allow the use of a predicated subtype. Msg is passed to
181 -- Error_Msg_FE to output an appropriate message using N as the location,
182 -- and Typ as the entity. The caller must set up any insertions other than
183 -- the & for the type itself. Note that if Typ is a generic actual type,
184 -- then the message will be output as a warning, and a raise Program_Error
185 -- is inserted using Insert_Action with node N as the insertion point. Node
186 -- N also supplies the source location for construction of the raise node.
187 -- If Typ does not have any predicates, the call has no effect. Set flag
188 -- Suggest_Static when the context warrants an advice on how to avoid the
189 -- use error.
191 function Bad_Unordered_Enumeration_Reference
194 -- Node N contains a potentially dubious reference to type T, either an
195 -- explicit comparison, or an explicit range. This function returns True
196 -- if the type T is an enumeration type for which No pragma Order has been
197 -- given, and the reference N is not in the same extended source unit as
198 -- the declaration of T.
200 function Build_Actual_Subtype
203 -- Build an anonymous subtype for an entity or expression, using the
204 -- bounds of the entity or the discriminants of the enclosing record.
205 -- T is the type for which the actual subtype is required, and N is either
206 -- a defining identifier, or any subexpression.
208 function Build_Actual_Subtype_Of_Component
211 -- Determine whether a selected component has a type that depends on
212 -- discriminants, and build actual subtype for it if so.
214 function Build_Default_Init_Cond_Call
218 -- Build a call to the default initial condition procedure of type Typ with
219 -- Obj_Id as the actual parameter.
222 -- Inspect the contents of private declarations Priv_Decls and build the
223 -- bodies the default initial condition procedures for all types subject
224 -- to pragma Default_Initial_Condition.
227 -- If private type Typ is subject to pragma Default_Initial_Condition,
228 -- build the declaration of the procedure which verifies the assumption
229 -- of the pragma at runtime. The declaration is inserted after the related
230 -- pragma.
232 function Build_Default_Subtype
235 -- If T is an unconstrained type with defaulted discriminants, build a
236 -- subtype constrained by the default values, insert the subtype
237 -- declaration in the tree before N, and return the entity of that
238 -- subtype. Otherwise, simply return T.
240 function Build_Discriminal_Subtype_Of_Component
242 -- Determine whether a record component has a type that depends on
243 -- discriminants, and build actual subtype for it if so.
246 -- Given a compilation unit node N, allocate an elaboration counter for
247 -- the compilation unit, and install it in the Elaboration_Entity field
248 -- of Spec_Id, the entity for the compilation unit.
250 procedure Build_Explicit_Dereference
253 -- AI05-139: Names with implicit dereference. If the expression N is a
254 -- reference type and the context imposes the corresponding designated
255 -- type, convert N into N.Disc.all. Such expressions are always over-
256 -- loaded with both interpretations, and the dereference interpretation
257 -- carries the name of the reference discriminant.
260 -- Returns True if the expression cannot possibly raise Constraint_Error.
261 -- The response is conservative in the sense that a result of False does
262 -- not necessarily mean that CE could be raised, but a response of True
263 -- means that for sure CE cannot be raised.
265 procedure Check_Dynamically_Tagged_Expression
269 -- Check wrong use of dynamically tagged expression
272 -- Verify that the full declaration of type T has been seen. If not, place
273 -- error message on node N. Used in object declarations, type conversions
274 -- and qualified expressions.
277 -- (Ada 2012): If the construct N has two or more direct constituents that
278 -- are names or expressions whose evaluation may occur in an arbitrary
279 -- order, at least one of which contains a function call with an in out or
280 -- out parameter, then the construct is legal only if: for each name that
281 -- is passed as a parameter of mode in out or out to some inner function
282 -- call C2 (not including the construct N itself), there is no other name
283 -- anywhere within a direct constituent of the construct C other than
284 -- the one containing C2, that is known to refer to the same object (RM
285 -- 6.4.1(6.17/3)).
288 -- AI05-139-2: Accessors and iterators for containers. This procedure
289 -- checks whether T is a reference type, and if so it adds an interprettion
290 -- to Expr whose type is the designated type of the reference_discriminant.
293 -- Within a protected function, the current object is a constant, and
294 -- internal calls to a procedure or entry are illegal. Similarly, other
295 -- uses of a protected procedure in a renaming or a generic instantiation
296 -- in the context of a protected function are illegal (AI05-0225).
298 procedure Check_Later_Vs_Basic_Declarations
301 -- If During_Parsing is True, check for misplacement of later vs basic
302 -- declarations in Ada 83. If During_Parsing is False, and the SPARK
303 -- restriction is set, do the same: although SPARK 95 removes the
304 -- distinction between initial and later declarative items, the distinction
305 -- remains in the Examiner (JB01-005). Note that the Examiner does not
306 -- count package declarations in later declarative items.
309 -- Check whether Ent denotes an entity declared in an uplevel scope, which
310 -- is accessed inside a nested procedure, and set Has_Up_Level_Access flag
311 -- accordingly. This is currently only enabled for VM_Target /= No_VM.
314 -- Determine whether object or state Id introduces a hidden state. If this
315 -- is the case, emit an error.
318 -- N is one of the statement forms that is a potentially blocking
319 -- operation. If it appears within a protected action, emit warning.
321 procedure Check_Result_And_Post_State
324 -- Determine whether pragma Prag mentions attribute 'Result and whether
325 -- the pragma contains an expression that evaluates differently in pre-
326 -- and post-state. Prag is a [refined] postcondition or a contract-cases
327 -- pragma. Result_Seen is set when the pragma mentions attribute 'Result.
329 procedure Check_Unprotected_Access
332 -- Check whether the expression is a pointer to a protected component,
333 -- and the context is external to the protected operation, to warn against
334 -- a possible unlocked access to data.
336 procedure Collect_Interfaces
341 -- Ada 2005 (AI-251): Collect whole list of abstract interfaces that are
342 -- directly or indirectly implemented by T. Exclude_Parents is used to
343 -- avoid the addition of inherited interfaces to the generated list.
344 -- Use_Full_View is used to collect the interfaces using the full-view
345 -- (if available).
347 procedure Collect_Interface_Components
350 -- Ada 2005 (AI-251): Collect all the tag components associated with the
351 -- secondary dispatch tables of a tagged type.
353 procedure Collect_Interfaces_Info
358 -- Ada 2005 (AI-251): Collect all the interfaces associated with T plus
359 -- the record component and tag associated with each of these interfaces.
360 -- On exit Ifaces_List, Components_List and Tags_List have the same number
361 -- of elements, and elements at the same position on these tables provide
362 -- information on the same interface type.
364 procedure Collect_Parents
368 -- Collect all the parents of Typ. Use_Full_View is used to collect them
369 -- using the full-view of private parents (if available).
372 -- Called upon type derivation and extension. We scan the declarative part
373 -- in which the type appears, and collect subprograms that have one
374 -- subsidiary subtype of the type. These subprograms can only appear after
375 -- the type itself.
377 function Compile_Time_Constraint_Error
383 -- This is similar to Apply_Compile_Time_Constraint_Error in that it
384 -- generates a warning (or error) message in the same manner, but it does
385 -- not replace any nodes. For convenience, the function always returns its
386 -- first argument. The message is a warning if the message ends with ?, or
387 -- we are operating in Ada 83 mode, or the Warn parameter is set to True.
390 -- Sets the Has_Delayed_Freeze flag of New if the Delayed_Freeze flag of
391 -- Old is set and Old has no yet been Frozen (i.e. Is_Frozen is false).
394 -- Determine whether pragma Prag contains a reference to the entity of an
395 -- abstract state with a visible refinement. Prag must denote one of the
396 -- following pragmas:
397 -- Depends
398 -- Global
401 -- Utility to create a parameter profile for a new subprogram spec, when
402 -- the subprogram has a body that acts as spec. This is done for some cases
403 -- of inlining, and for private protected ops. Also used to create bodies
404 -- for stubbed subprograms.
406 function Copy_Component_List
409 -- Copy components from record type R_Typ that come from source. Used to
410 -- create a new compatible record type. Loc is the source location assigned
411 -- to the created nodes.
414 -- If a type is a generic actual type, return the corresponding formal in
415 -- the generic parent unit. There is no direct link in the tree for this
416 -- attribute, except in the case of formal private and derived types.
417 -- Possible optimization???
421 -- Find the currently visible definition for a given identifier, that is to
422 -- say the first entry in the visibility chain for the Chars of N.
425 -- Find whether there is a previous definition for identifier N in the
426 -- current scope. Because declarations for a scope are not necessarily
427 -- contiguous (e.g. for packages) the first entry on the visibility chain
428 -- for N is not necessarily in the current scope.
431 -- Get entity representing current scope
434 -- Returns current enclosing subprogram. If Current_Scope is a subprogram,
435 -- then that is what is returned, otherwise the Enclosing_Subprogram of the
436 -- Current_Scope is returned. The returned value is Empty if this is called
437 -- from a library package which is not within any subprogram.
440 -- Same as Type_Access_Level, except that if the type is the type of an Ada
441 -- 2012 stand-alone object of an anonymous access type, then return the
442 -- static accesssibility level of the object. In that case, the dynamic
443 -- accessibility level of the object may take on values in a range. The low
444 -- bound of of that range is returned by Type_Access_Level; this function
445 -- yields the high bound of that range. Also differs from Type_Access_Level
446 -- in the case of a descendant of a generic formal type (returns Int'Last
447 -- instead of 0).
450 -- Given a declaration N, returns the associated defining entity. If the
451 -- declaration has a specification, the entity is obtained from the
452 -- specification. If the declaration has a defining unit name, then the
453 -- defining entity is obtained from the defining unit name ignoring any
454 -- child unit prefixes.
455 --
456 -- Iterator loops also have a defining entity, which holds the list of
457 -- local entities declared during loop expansion. These entities need
458 -- debugging information, generated through QUalify_Entity_Names, and
459 -- the loop declaration must be placed in the table Name_Qualify_Units.
461 function Denotes_Discriminant
464 -- Returns True if node N is an Entity_Name node for a discriminant. If the
465 -- flag Check_Concurrent is true, function also returns true when N denotes
466 -- the discriminal of the discriminant of a concurrent type. This is needed
467 -- to disable some optimizations on private components of protected types,
468 -- and constraint checks on entry families constrained by discriminants.
471 -- Detect suspicious overlapping between actuals in a call, when both are
472 -- writable (RM 2012 6.4.1(6.4/3))
475 -- Functions to detect suspicious overlapping between actuals in a call,
476 -- when one of them is writable. The predicates are those proposed in
477 -- AI05-0144, to detect dangerous order dependence in complex calls.
478 -- I would add a parameter Warn which enables more extensive testing of
479 -- cases as we find appropriate when we are only warning ??? Or perhaps
480 -- return an indication of (Error, Warn, OK) ???
483 -- Returns True if node N denotes a single variable without parentheses
486 -- Returns True if N denotes a discriminant or if N is a range, a subtype
487 -- indication or a scalar subtype where one of the bounds is a
488 -- discriminant.
490 function Designate_Same_Unit
493 -- Return true if Name1 and Name2 designate the same unit name; each of
494 -- these names is supposed to be a selected component name, an expanded
495 -- name, a defining program unit name or an identifier.
498 -- Expr should be an expression of an access type. Builds an integer
499 -- literal except in cases involving anonymous access types where
500 -- accessibility levels are tracked at runtime (access parameters and Ada
501 -- 2012 stand-alone objects).
504 -- Same as Einfo.Extra_Accessibility except thtat object renames
505 -- are looked through.
508 -- Given the entity of an abstract state or a variable, determine whether
509 -- Id is subject to external property Effective_Reads and if it is, the
510 -- related expression evaluates to True.
513 -- Given the entity of an abstract state or a variable, determine whether
514 -- Id is subject to external property Effective_Writes and if it is, the
515 -- related expression evaluates to True.
518 -- Returns the enclosing N_Compilation_Unit Node that is the root of a
519 -- subtree containing N.
522 -- Returns the closest ancestor of Typ that is a CPP type.
524 function Enclosing_Generic_Body
526 -- Returns the Node_Id associated with the innermost enclosing generic
527 -- body, if any. If none, then returns Empty.
529 function Enclosing_Generic_Unit
531 -- Returns the Node_Id associated with the innermost enclosing generic
532 -- unit, if any. If none, then returns Empty.
534 function Enclosing_Lib_Unit_Entity
536 -- Returns the entity of enclosing library unit node which is the
537 -- root of the current scope (which must not be Standard_Standard, and the
538 -- caller is responsible for ensuring this condition) or other specified
539 -- entity.
542 -- Utility function to return the Ada entity of the package enclosing
543 -- the entity E, if any. Returns Empty if no enclosing package.
546 -- Utility function to return the Ada entity of the subprogram enclosing
547 -- the entity E, if any. Returns Empty if no enclosing subprogram.
550 -- Make sure a freeze node is allocated for entity E. If necessary, build
551 -- and initialize a new freeze node and set Has_Delayed_Freeze True for E.
554 -- Insert new name in symbol table of current scope with check for
555 -- duplications (error message is issued if a conflict is found).
556 -- Note: Enter_Name is not used for overloadable entities, instead these
557 -- are entered using Sem_Ch6.Enter_Overloadable_Entity.
560 -- Return the entity of N or Empty. If N is a renaming, return the entity
561 -- of the root renamed object.
564 -- This procedure is called after issuing a message complaining about an
565 -- inappropriate use of limited type T. If useful, it adds additional
566 -- continuation lines to the message explaining why type T is limited.
567 -- Messages are placed at node N.
569 procedure Find_Actual
573 -- Determines if the node N is an actual parameter of a function of a
574 -- procedure call. If so, then Formal points to the entity for the formal
575 -- (Ekind is E_In_Parameter, E_Out_Parameter, or E_In_Out_Parameter) and
576 -- Call is set to the node for the corresponding call. If the node N is not
577 -- an actual parameter then Formal and Call are set to Empty.
580 -- Find specific type of a class-wide type, and handle the case of an
581 -- incomplete type coming either from a limited_with clause or from an
582 -- incomplete type declaration. If resulting type is private return its
583 -- full view.
585 function Find_Body_Discriminal
587 -- Given a discriminant of the record type that implements a task or
588 -- protected type, return the discriminal of the corresponding discriminant
589 -- of the actual concurrent type.
591 function Find_Corresponding_Discriminant
594 -- Because discriminants may have different names in a generic unit and in
595 -- an instance, they are resolved positionally when possible. A reference
596 -- to a discriminant carries the discriminant that it denotes when it is
597 -- analyzed. Subsequent uses of this id on a different type denotes the
598 -- discriminant at the same position in this new type.
601 -- Given an arbitrary entity, try to find the nearest enclosing iterator
602 -- loop. If such a loop is found, return the entity of its identifier (the
603 -- E_Loop scope), otherwise return Empty.
606 -- Find the nested loop statement in a conditional block. Loops subject to
607 -- attribute 'Loop_Entry are transformed into blocks. Parts of the original
608 -- loop are nested within the block.
610 procedure Find_Overlaid_Entity
614 -- The node N should be an address representation clause. Determines if
615 -- the target expression is the address of an entity with an optional
616 -- offset. If so, set Ent to the entity and, if there is an offset, set
617 -- Off to True, otherwise to False. If N is not an address representation
618 -- clause, or if it is not possible to determine that the address is of
619 -- this form, then set Ent to Empty.
622 -- Return the type of formal parameter Param as determined by its
623 -- specification.
625 -- The following type describes the placement of an arbitrary entity with
626 -- respect to SPARK visible / hidden state space.
630 -- An entity is not in the visible, private or body state space when
631 -- the immediate enclosing construct is not a package.
633 Visible_State_Space,
634 -- An entity is in the visible state space when it appears immediately
635 -- within the visible declarations of a package or when it appears in
636 -- the visible state space of a nested package which in turn is declared
637 -- in the visible declarations of an enclosing package:
639 -- package Pack is
640 -- Visible_Variable : ...
641 -- package Nested
642 -- with Abstract_State => Visible_State
643 -- is
644 -- Visible_Nested_Variable : ...
645 -- end Nested;
646 -- end Pack;
648 -- Entities associated with a package instantiation inherit the state
649 -- space from the instance placement:
651 -- generic
652 -- package Gen is
653 -- Generic_Variable : ...
654 -- end Gen;
656 -- with Gen;
657 -- package Pack is
658 -- package Inst is new Gen;
659 -- -- Generic_Variable is in the visible state space of Pack
660 -- end Pack;
662 Private_State_Space,
663 -- An entity is in the private state space when it appears immediately
664 -- within the private declarations of a package or when it appears in
665 -- the visible state space of a nested package which in turn is declared
666 -- in the private declarations of an enclosing package:
668 -- package Pack is
669 -- private
670 -- Private_Variable : ...
671 -- package Nested
672 -- with Abstract_State => Private_State
673 -- is
674 -- Private_Nested_Variable : ...
675 -- end Nested;
676 -- end Pack;
678 -- The same placement principle applies to package instantiations
680 Body_State_Space);
681 -- An entity is in the body state space when it appears immediately
682 -- within the declarations of a package body or when it appears in the
683 -- visible state space of a nested package which in turn is declared in
684 -- the declarations of an enclosing package body:
686 -- package body Pack is
687 -- Body_Variable : ...
688 -- package Nested
689 -- with Abstract_State => Body_State
690 -- is
691 -- Body_Nested_Variable : ...
692 -- end Nested;
693 -- end Pack;
695 -- The same placement principle applies to package instantiations
697 procedure Find_Placement_In_State_Space
701 -- Determine the state space placement of an item. Item_Id denotes the
702 -- entity of an abstract state, variable or package instantiation.
703 -- Placement captures the precise placement of the item in the enclosing
704 -- state space. If the state space is that of a package, Pack_Id denotes
705 -- its entity, otherwise Pack_Id is Empty.
708 -- N is a case statement whose expression is a compile-time value.
709 -- Determine the alternative chosen, so that the code of non-selected
710 -- alternatives, and the warnings that may apply to them, are removed.
713 -- Node is an N_Function_Call or N_Procedure_Call_Statement node. The
714 -- result returned is the first actual parameter in declaration order
715 -- (not the order of parameters as they appeared in the source, which
716 -- can be quite different as a result of the use of named parameters).
717 -- Empty is returned for a call with no parameters. The procedure for
718 -- iterating through the actuals in declaration order is to use this
719 -- function to find the first actual, and then use Next_Actual to obtain
720 -- the next actual in declaration order. Note that the value returned
721 -- is always the expression (not the N_Parameter_Association nodes,
722 -- even if named association is used).
724 procedure Gather_Components
730 -- The purpose of this procedure is to gather the valid components in a
731 -- record type according to the values of its discriminants, in order to
732 -- validate the components of a record aggregate.
733 --
734 -- Typ is the type of the aggregate when its constrained discriminants
735 -- need to be collected, otherwise it is Empty.
736 --
737 -- Comp_List is an N_Component_List node.
738 --
739 -- Governed_By is a list of N_Component_Association nodes, where each
740 -- choice list contains the name of a discriminant and the expression
741 -- field gives its value. The values of the discriminants governing
742 -- the (possibly nested) variant parts in Comp_List are found in this
743 -- Component_Association List.
744 --
745 -- Into is the list where the valid components are appended. Note that
746 -- Into need not be an Empty list. If it's not, components are attached
747 -- to its tail.
748 --
749 -- Report_Errors is set to True if the values of the discriminants are
750 -- non-static.
751 --
752 -- This procedure is also used when building a record subtype. If the
753 -- discriminant constraint of the subtype is static, the components of the
754 -- subtype are only those of the variants selected by the values of the
755 -- discriminants. Otherwise all components of the parent must be included
756 -- in the subtype for semantic analysis.
759 -- Given a node for an expression, obtain the actual subtype of the
760 -- expression. In the case of a parameter where the formal is an
761 -- unconstrained array or discriminated type, this will be the previously
762 -- constructed subtype of the actual. Note that this is not quite the
763 -- "Actual Subtype" of the RM, since it is always a constrained type, i.e.
764 -- it is the subtype of the value of the actual. The actual subtype is also
765 -- returned in other cases where it has already been constructed for an
766 -- object. Otherwise the expression type is returned unchanged, except for
767 -- the case of an unconstrained array type, where an actual subtype is
768 -- created, using Insert_Actions if necessary to insert any associated
769 -- actions.
772 -- This is like Get_Actual_Subtype, except that it never constructs an
773 -- actual subtype. If an actual subtype is already available, i.e. the
774 -- Actual_Subtype field of the corresponding entity is set, then it is
775 -- returned. Otherwise the Etype of the node is returned.
778 -- Return the body node for a stub (subprogram or package)
780 function Get_Cursor_Type
783 -- Find Cursor type in scope of formal container Typ, by locating primitive
784 -- operation First. For use in resolving the other primitive operations
785 -- of an Iterable type and expanding loops and quantified expressions
786 -- over formal containers.
789 -- This is used to construct the string literal node representing a
790 -- default external name, i.e. one that is constructed from the name of an
791 -- entity, or (in the case of extended DEC import/export pragmas, an
792 -- identifier provided as the external name. Letters in the name are
793 -- according to the setting of Opt.External_Name_Default_Casing.
796 -- If expression N references a part of an object, return this object.
797 -- Otherwise return Empty. Expression N should have been resolved already.
800 -- Return the Ensures component of Test_Case pragma N, or Empty otherwise
801 -- Bad name now that this no longer applies to Contract_Case ???
804 -- Returns the true generic entity in an instantiation. If the name in the
805 -- instantiation is a renaming, the function returns the renamed generic.
808 -- Implements the notion introduced ever-so briefly in RM 7.3.1 (5.2/3):
809 -- in a child unit a derived type is within the derivation class of an
810 -- ancestor declared in a parent unit, even if there is an intermediate
811 -- derivation that does not see the full view of that ancestor.
814 -- This procedure assigns to L and H respectively the values of the low and
815 -- high bounds of node N, which must be a range, subtype indication, or the
816 -- name of a scalar subtype. The result in L, H may be set to Error if
817 -- there was an earlier error in the range.
819 function Get_Enum_Lit_From_Pos
823 -- This function returns an identifier denoting the E_Enumeration_Literal
824 -- entity for the specified value from the enumeration type or subtype T.
825 -- The second argument is the Pos value, which is assumed to be in range.
826 -- The third argument supplies a source location for constructed nodes
827 -- returned by this function.
829 function Get_Iterable_Type_Primitive
832 -- Retrieve one of the primitives First, Next, Has_Element, Element from
833 -- the value of the Iterable aspect of a formal type.
836 -- Retrieve the fully expanded name of the library unit declared by
837 -- Decl_Node into the name buffer.
841 -- An entity value is associated with each name in the name table. The
842 -- Get_Name_Entity_Id function fetches the Entity_Id of this entity, which
843 -- is the innermost visible entity with the given name. See the body of
844 -- Sem_Ch8 for further details on handling of entity visibility.
847 -- Return the Name component of Test_Case pragma N
848 -- Bad name now that this no longer applies to Contract_Case ???
851 -- Get defining entity of parent unit of a child unit. In most cases this
852 -- is the defining entity of the unit, but for a child instance whose
853 -- parent needs a body for inlining, the instantiation node of the parent
854 -- has not yet been rewritten as a package declaration, and the entity has
855 -- to be retrieved from the Instance_Spec of the unit.
859 -- Obtains the Pragma_Id from the Chars field of Pragma_Identifier (N)
862 -- Recursive routine to analyze reason argument for pragma Warnings. The
863 -- value of the reason argument is appended to the current string using
864 -- Store_String_Chars. The reason argument is expected to be a string
865 -- literal or concatenation of string literals. An error is given for
866 -- any other form.
869 -- Given a node, return the renamed object if the node represents a renamed
870 -- object, otherwise return the node unchanged. The node may represent an
871 -- arbitrary expression.
874 -- Given an entity for an exception, package, subprogram or generic unit,
875 -- returns the ultimately renamed entity if this is a renaming. If this is
876 -- not a renamed entity, returns its argument. It is an error to call this
877 -- with any other kind of entity.
880 -- Return the Requires component of Test_Case pragma N, or Empty otherwise
881 -- Bad name now that this no longer applies to Contract_Case ???
884 -- Nod is either a procedure call statement, or a function call, or an
885 -- accept statement node. This procedure finds the Entity_Id of the related
886 -- subprogram or entry and returns it, or if no subprogram can be found,
887 -- returns Empty.
890 -- Given the entity for a subprogram (E_Function or E_Procedure), return
891 -- the corresponding N_Subprogram_Body node. If the corresponding body
892 -- is missing (as for an imported subprogram), return Empty.
896 -- Given an entity for a task type or subtype, retrieves the
897 -- Task_Body_Procedure field from the corresponding task type declaration.
900 -- Returns true if type or subtype T is an access type, or has a component
901 -- (at any recursive level) that is an access type. This is a conservative
902 -- predicate, if it is not known whether or not T contains access values
903 -- (happens for generic formals in some cases), then False is returned.
904 -- Note that tagged types return False. Even though the tag is implemented
905 -- as an access type internally, this function tests only for access types
906 -- known to the programmer. See also Has_Tagged_Component.
909 -- Simple predicate to test for defaulted discriminants
912 -- Result of Has_Compatible_Alignment test, description found below. Note
913 -- that the values are arranged in increasing order of problematicness.
915 function Has_Compatible_Alignment
918 -- Obj is an object entity, and expr is a node for an object reference. If
919 -- the alignment of the object referenced by Expr is known to be compatible
920 -- with the alignment of Obj (i.e. is larger or the same), then the result
921 -- is Known_Compatible. If the alignment of the object referenced by Expr
922 -- is known to be less than the alignment of Obj, then Known_Incompatible
923 -- is returned. If neither condition can be reliably established at compile
924 -- time, then Unknown is returned. This is used to determine if alignment
925 -- checks are required for address clauses, and also whether copies must
926 -- be made when objects are passed by reference.
927 --
928 -- Note: Known_Incompatible does not mean that at run time the alignment
929 -- of Expr is known to be wrong for Obj, just that it can be determined
930 -- that alignments have been explicitly or implicitly specified which are
931 -- incompatible (whereas Unknown means that even this is not known). The
932 -- appropriate reaction of a caller to Known_Incompatible is to treat it as
933 -- Unknown, but issue a warning that there may be an alignment error.
936 -- Determines if the node can have declarations
939 -- Determines if the floating-point type E supports denormal numbers.
940 -- Returns False if E is not a floating-point type.
942 function Has_Discriminant_Dependent_Constraint
944 -- Returns True if and only if Comp has a constrained subtype that depends
945 -- on a discriminant.
948 -- Determines if the range of the floating-point type E includes
949 -- infinities. Returns False if E is not a floating-point type.
951 function Has_Interfaces
954 -- Where T is a concurrent type or a record type, returns true if T covers
955 -- any abstract interface types. In case of private types the argument
956 -- Use_Full_View controls if the check is done using its full view (if
957 -- available).
960 -- This is a simple minded function for determining whether an expression
961 -- has no obvious side effects. It is used only for determining whether
962 -- warnings are needed in certain situations, and is not guaranteed to
963 -- be accurate in either direction. Exceptions may mean an expression
964 -- does in fact have side effects, but this may be ignored and True is
965 -- returned, or a complex expression may in fact be side effect free
966 -- but we don't recognize it here and return False. The Side_Effect_Free
967 -- routine in Remove_Side_Effects is much more extensive and perhaps could
968 -- be shared, so that this routine would be more accurate.
971 -- Determine whether node N has a null exclusion
974 -- Predicate to determine whether a controlled type has a user-defined
975 -- Initialize primitive (and, in Ada 2012, whether that primitive is
976 -- non-null), which causes the type to not have preelaborable
977 -- initialization.
980 -- Return True iff type E has preelaborable initialization as defined in
981 -- Ada 2005 (see AI-161 for details of the definition of this attribute).
984 -- Check if a type has a (sub)component of a private type that has not
985 -- yet received a full declaration.
988 -- Determines if the floating-point type E supports signed zeros.
989 -- Returns False if E is not a floating-point type.
992 -- Return whether an array type has static bounds
995 -- Tests if type T is derived from Ada.Streams.Root_Stream_Type, or in the
996 -- case of a composite type, has a component for which this predicate is
997 -- True, and if so returns True. Otherwise a result of False means that
998 -- there is no Stream type in sight. For a private type, the test is
999 -- applied to the underlying type (or returns False if there is no
1000 -- underlying type).
1003 -- Returns true if the last character of E is Suffix. Used in Assertions.
1006 -- Returns the name of E adding Suffix
1009 -- Returns the name of E without Suffix
1012 -- Returns True if Typ is a composite type (array or record) which is
1013 -- either itself a tagged type, or has a component (recursively) which is
1014 -- a tagged type. Returns False for non-composite type, or if no tagged
1015 -- component is present. This function is used to check if "=" has to be
1016 -- expanded into a bunch component comparisons.
1019 -- Given an arbitrary type, determine whether it contains at least one
1020 -- volatile component.
1023 -- Subp is a subprogram marked with pragma Implemented. Return the specific
1024 -- implementation requirement which the pragma imposes. The return value is
1025 -- either Name_By_Any, Name_By_Entry or Name_By_Protected_Procedure.
1027 function Implements_Interface
1031 -- Returns true if the Typ_Ent implements interface Iface_Ent
1034 -- Determine whether an arbitrary node appears in a pragma that acts as an
1035 -- assertion expression. See Sem_Prag for the list of qualifying pragmas.
1038 -- Returns True if the current scope is within a generic instance
1041 -- Returns True if current scope is within the body of an instance, where
1042 -- several semantic checks (e.g. accessibility checks) are relaxed.
1045 -- Returns True if current scope is with the private part or the body of
1046 -- an instance. Other semantic checks are suppressed in this context.
1049 -- Returns True if current scope is within the visible part of a package
1050 -- instance, where several additional semantic checks apply.
1053 -- Returns True if current scope is within a package body
1056 -- Returns True if node N belongs to a parameter specification
1059 -- Returns true if the expression N occurs within a pragma with name Nam
1062 -- Returns True if N denotes a component or subcomponent in a record or
1063 -- array that has Reverse_Storage_Order.
1066 -- Determines if the current scope is within a subprogram compilation unit
1067 -- (inside a subprogram declaration, subprogram body, or generic subprogram
1068 -- declaration) or within a task or protected body. The test is for
1069 -- appearing anywhere within such a construct (that is it does not need
1070 -- to be directly within).
1073 -- Determine whether a declaration occurs within the visible part of a
1074 -- package specification. The package must be on the scope stack, and the
1075 -- corresponding private part must not.
1078 -- Given the entity of a type, retrieve the incomplete or private view of
1079 -- the same type. Note that Typ may not have a partial view to begin with,
1080 -- in that case the function returns Empty.
1083 -- Inherit the default initial condition procedure from the parent type of
1084 -- derived type Typ.
1087 -- In a context that requires a composite or subprogram type and where a
1088 -- prefix is an access type, rewrite the access type node N (which is the
1089 -- prefix, e.g. of an indexed component) as an explicit dereference.
1092 -- Examine all deferred constants in the declaration list Decls and check
1093 -- whether they have been completed by a full constant declaration or an
1094 -- Import pragma. Emit the error message if that is not the case.
1097 -- Determines if N is an actual parameter of out mode in a subprogram call
1100 -- Determines if N is an actual parameter in a subprogram call
1103 -- Determines if N is an actual parameter of a formal of tagged type in a
1104 -- subprogram call.
1107 -- Determine if Obj is an aliased view, i.e. the name of an object to which
1108 -- 'Access or 'Unchecked_Access can apply. Note that this routine uses the
1109 -- rules of the language, it does not take into account the restriction
1110 -- No_Implicit_Aliasing, so it can return True if the restriction is active
1111 -- and Obj violates the restriction. The caller is responsible for calling
1112 -- Restrict.Check_No_Implicit_Aliasing if True is returned, but there is a
1113 -- requirement for obeying the restriction in the call context.
1115 function Is_Ancestor_Package
1118 -- Determine whether package E1 is an ancestor of E2
1121 -- Determines if the given node denotes an atomic object in the sense of
1122 -- the legality checks described in RM C.6(12).
1125 -- Determine whether node N denotes attribute 'Result
1128 -- Determine whether node N denotes a body or a package declaration
1131 -- True if T is a bounded string type. Used to make sure "=" composes
1132 -- properly for bounded string types.
1135 -- Exp is the expression for an array bound. Determines whether the
1136 -- bound is a compile-time known value, or a constant entity, or an
1137 -- enumeration literal, or an expression composed of constant-bound
1138 -- subexpressions which are evaluated by means of standard operators.
1141 -- This routine recognizes expressions that denote an element of one of
1142 -- the predefined containers, when the source only contains an indexing
1143 -- operation and an implicit dereference is inserted by the compiler.
1144 -- In the absence of this optimization, the indexing creates a temporary
1145 -- controlled cursor that sets the tampering bit of the container, and
1146 -- restricts the use of the convenient notation C (X) to contexts that
1147 -- do not check the tampering bit (e.g. C.Include (X, C (Y)). Exp is an
1148 -- explicit dereference. The transformation applies when it has the form
1149 -- F (X).Discr.all.
1151 function Is_Controlling_Limited_Procedure
1153 -- Ada 2005 (AI-345): Determine whether Proc_Nam is a primitive procedure
1154 -- of a limited interface with a controlling first parameter.
1157 -- Returns True if N is a call to a CPP constructor
1159 function Is_Child_Or_Sibling
1162 -- Determine the following relations between two arbitrary packages:
1163 -- 1) One package is the parent of a child package
1164 -- 2) Both packages are siblings and share a common parent
1167 -- First determine whether type T is an interface and then check whether
1168 -- it is of protected, synchronized or task kind.
1171 -- Returns true if type T represents a delegate. A Delegate is the CIL
1172 -- object used to represent access-to-subprogram types. This is only
1173 -- relevant to CIL, will always return false for other targets.
1175 function Is_Dependent_Component_Of_Mutable_Object
1177 -- Returns True if Object is the name of a subcomponent that depends on
1178 -- discriminants of a variable whose nominal subtype is unconstrained and
1179 -- not indefinite, and the variable is not aliased. Otherwise returns
1180 -- False. The nodes passed to this function are assumed to denote objects.
1183 -- N is a subexpression node of an access type. This function returns true
1184 -- if N appears as the prefix of a node that does a dereference of the
1185 -- access value (selected/indexed component, explicit dereference or a
1186 -- slice), and false otherwise.
1189 -- Returns True if type T1 is a descendent of type T2, and false otherwise.
1190 -- This is the RM definition, a type is a descendent of another type if it
1191 -- is the same type or is derived from a descendent of the other type.
1194 -- The SPARK property "effectively volatile" applies to both types and
1195 -- objects. To qualify as such, an entity must be either volatile or be
1196 -- (of) an array type subject to aspect Volatile_Components.
1199 -- Determine whether an arbitrary node denotes an effectively volatile
1200 -- object.
1203 -- Predicate to determine whether a scope entity comes from a rewritten
1204 -- expression function call, and should be inlined unconditionally. Also
1205 -- used to determine that such a call does not constitute a freeze point.
1209 -- The argument is a Uint value which is the Boolean'Pos value of a Boolean
1210 -- operand (i.e. is either 0 for False, or 1 for True). This function tests
1211 -- if it is False (i.e. zero).
1214 -- Returns True iff the number U is a model number of the fixed-point type
1215 -- T, i.e. if it is an exact multiple of Small.
1218 -- Typ is a type entity. This function returns true if this type is fully
1219 -- initialized, meaning that an object of the type is fully initialized.
1220 -- Note that initialization resulting from use of pragma Normalized_Scalars
1221 -- does not count. Note that this is only used for the purpose of issuing
1222 -- warnings for objects that are potentially referenced uninitialized. This
1223 -- means that the result returned is not crucial, but should err on the
1224 -- side of thinking things are fully initialized if it does not know.
1227 -- E is a subprogram. Return True is E is an implicit operation inherited
1228 -- by a derived type declaration.
1230 function Is_Inherited_Operation_For_Type
1233 -- E is a subprogram. Return True is E is an implicit operation inherited
1234 -- by the derived type declaration for type Typ.
1237 -- AI05-0139-2: Check whether Typ is one of the predefined interfaces in
1238 -- Ada.Iterator_Interfaces, or it is derived from one.
1242 -- Returns Yes if N is definitely used as Name in an assignment statement.
1243 -- Returns No if N is definitely NOT used as a Name in an assignment
1244 -- statement. Returns Unknown if we can't tell at this stage (happens in
1245 -- the case where we don't know the type of N yet, and we have something
1246 -- like N.A := 3, where this counts as N being used on the left side of
1247 -- an assignment only if N is not an access type. If it is an access type
1248 -- then it is N.all.A that is assigned, not N.
1251 -- A library-level declaration is one that is accessible from Standard,
1252 -- i.e. a library unit or an entity declared in a library package.
1255 -- Determine whether a given type is a limited class-wide type, in which
1256 -- case it needs a Master_Id, because extensions of its designated type
1257 -- may include task components. A class-wide type that comes from a
1258 -- limited view must be treated in the same way.
1261 -- Determines whether Expr is a reference to a variable or IN OUT mode
1262 -- parameter of the current enclosing subprogram.
1263 -- Why are OUT parameters not considered here ???
1266 -- Determines if the tree referenced by N represents an object. Both
1267 -- variable and constant objects return True (compare Is_Variable).
1270 -- Used to test if AV is an acceptable formal for an OUT or IN OUT formal.
1271 -- Note that the Is_Variable function is not quite the right test because
1272 -- this is a case in which conversions whose expression is a variable (in
1273 -- the Is_Variable sense) with an untagged type target are considered view
1274 -- conversions and hence variables.
1276 function Is_Partially_Initialized_Type
1279 -- Typ is a type entity. This function returns true if this type is partly
1280 -- initialized, meaning that an object of the type is at least partly
1281 -- initialized (in particular in the record case, that at least one
1282 -- component has an initialization expression). Note that initialization
1283 -- resulting from the use of pragma Normalized_Scalars does not count.
1284 -- Include_Implicit controls whether implicit initialization of access
1285 -- values to null, and of discriminant values, is counted as making the
1286 -- type be partially initialized. For the default setting of True, these
1287 -- implicit cases do count, and discriminated types or types containing
1288 -- access values not explicitly initialized will return True. Otherwise
1289 -- if Include_Implicit is False, these cases do not count as making the
1290 -- type be partially initialized.
1293 -- Predicate to implement definition given in RM 6.1.1 (20/3)
1296 -- Determines if type T is a potentially persistent type. A potentially
1297 -- persistent type is defined (recursively) as a scalar type, an untagged
1298 -- record whose components are all of a potentially persistent type, or an
1299 -- array with all static constraints whose component type is potentially
1300 -- persistent. A private type is potentially persistent if the full type
1301 -- is potentially persistent.
1304 -- Return True if node N denotes a protected type name which represents
1305 -- the current instance of a protected object according to RM 9.4(21/2).
1308 -- Return True if a compilation unit is the specification or the
1309 -- body of a remote call interface package.
1312 -- Return True if E is a remote access-to-class-wide type
1315 -- Return True if E is a remote access to subprogram type
1318 -- Return True if N denotes a potentially remote call
1321 -- Return True if Proc_Nam is a procedure renaming of an entry
1324 -- AI05-0139-2: Check whether Typ is derived from the predefined interface
1325 -- Ada.Iterator_Interfaces.Reversible_Iterator.
1328 -- Given an N_Identifier node N, determines if it is a Selector_Name.
1329 -- As described in Sinfo, Selector_Names are special because they
1330 -- represent use of the N_Identifier node for a true identifier, when
1331 -- normally such nodes represent a direct name.
1334 -- Determines if the tree referenced by N represents an initialization
1335 -- expression in SPARK 2005, suitable for initializing an object in an
1336 -- object declaration.
1339 -- Determines if the tree referenced by N represents an object in SPARK
1340 -- 2005. This differs from Is_Object_Reference in that only variables,
1341 -- constants, formal parameters, and selected_components of those are
1342 -- valid objects in SPARK 2005.
1346 -- Check if the node N is a statement node. Note that this includes
1347 -- the case of procedure call statements (unlike the direct use of
1348 -- the N_Statement_Other_Than_Procedure_Call subtype from Sinfo).
1349 -- Note that a label is *not* a statement, and will return False.
1351 function Is_Subprogram_Stub_Without_Prior_Declaration
1353 -- Return True if N is a subprogram stub with no prior subprogram
1354 -- declaration.
1357 -- Returns True if E is a synchronized tagged type (AARM 3.9.4 (6/2))
1360 -- Returns True if the node N is a statement which is known to cause an
1361 -- unconditional transfer of control at runtime, i.e. the following
1362 -- statement definitely will not be executed.
1366 -- The argument is a Uint value which is the Boolean'Pos value of a Boolean
1367 -- operand (i.e. is either 0 for False, or 1 for True). This function tests
1368 -- if it is True (i.e. non-zero).
1371 -- Determine whether an arbitrary entity denotes an instance of function
1372 -- Ada.Unchecked_Conversion.
1376 -- True if T is Universal_Integer or Universal_Real
1379 -- Returns true if type T represents a value type. This is only relevant to
1380 -- CIL, will always return false for other targets. A value type is a CIL
1381 -- object that is accessed directly, as opposed to the other CIL objects
1382 -- that are accessed through managed pointers.
1385 -- Returns true if E has variable size components
1388 -- Returns true if E has variable size components
1390 function Is_Variable
1393 -- Determines if the tree referenced by N represents a variable, i.e. can
1394 -- appear on the left side of an assignment. There is one situation (formal
1395 -- parameters) in which untagged type conversions are also considered
1396 -- variables, but Is_Variable returns False for such cases, since it has
1397 -- no knowledge of the context. Note that this is the point at which
1398 -- Assignment_OK is checked, and True is returned for any tree thus marked.
1399 -- Use_Original_Node is used to perform the test on Original_Node (N). By
1400 -- default is True since this routine is commonly invoked as part of the
1401 -- semantic analysis and it must not be disturbed by the rewriten nodes.
1404 -- Check whether T is derived from a visibly controlled type. This is true
1405 -- if the root type is declared in Ada.Finalization. If T is derived
1406 -- instead from a private type whose full view is controlled, an explicit
1407 -- Initialize/Adjust/Finalize subprogram does not override the inherited
1408 -- one.
1411 -- Determines if the given node denotes an volatile object in the sense of
1412 -- the legality checks described in RM C.6(12). Note that the test here is
1413 -- for something actually declared as volatile, not for an object that gets
1414 -- treated as volatile (see Einfo.Treat_As_Volatile).
1417 -- Applies to Itypes. True if the Itype is attached to a declaration for
1418 -- the type through its Parent field, which may or not be present in the
1419 -- tree.
1422 -- This procedure is called to clear all constant indications from all
1423 -- entities in the current scope and in any parent scopes if the current
1424 -- scope is a block or a package (and that recursion continues to the top
1425 -- scope that is not a block or a package). This is used when the
1426 -- sequential flow-of-control assumption is violated (occurrence of a
1427 -- label, head of a loop, or start of an exception handler). The effect of
1428 -- the call is to clear the Current_Value field (but we do not need to
1429 -- clear the Is_True_Constant flag, since that only gets reset if there
1430 -- really is an assignment somewhere in the entity scope). This procedure
1431 -- also calls Kill_All_Checks, since this is a special case of needing to
1432 -- forget saved values. This procedure also clears the Is_Known_Null and
1433 -- Is_Known_Non_Null and Is_Known_Valid flags in variables, constants or
1434 -- parameters since these are also not known to be trustable any more.
1435 --
1436 -- The Last_Assignment_Only flag is set True to clear only Last_Assignment
1437 -- fields and leave other fields unchanged. This is used when we encounter
1438 -- an unconditional flow of control change (return, goto, raise). In such
1439 -- cases we don't need to clear the current values, since it may be that
1440 -- the flow of control change occurs in a conditional context, and if it
1441 -- is not taken, then it is just fine to keep the current values. But the
1442 -- Last_Assignment field is different, if we have a sequence assign-to-v,
1443 -- conditional-return, assign-to-v, we do not want to complain that the
1444 -- second assignment clobbers the first.
1446 procedure Kill_Current_Values
1449 -- This performs the same processing as described above for the form with
1450 -- no argument, but for the specific entity given. The call has no effect
1451 -- if the entity Ent is not for an object. Last_Assignment_Only has the
1452 -- same meaning as for the call with no Ent.
1455 -- Called when an address clause or pragma Import is applied to an entity.
1456 -- If the entity is a variable or a constant, and size check code is
1457 -- present, this size check code is killed, since the object will not be
1458 -- allocated by the program.
1461 -- The node N is an entity reference. This function determines whether the
1462 -- reference is for sure an assignment of the entity, returning True if
1463 -- so. This differs from May_Be_Lvalue in that it defaults in the other
1464 -- direction. Cases which may possibly be assignments but are not known to
1465 -- be may return True from May_Be_Lvalue, but False from this function.
1468 -- HSS is a handled statement sequence. This function returns the last
1469 -- statement in Statements (HSS) that has Comes_From_Source set. If no
1470 -- such statement exists, Empty is returned.
1472 function Matching_Static_Array_Bounds
1475 -- L_Typ and R_Typ are two array types. Returns True when they have the
1476 -- same number of dimensions, and the same static bounds for each index
1477 -- position.
1480 -- Given a node which designates the context of analysis and an origin in
1481 -- the tree, traverse from Root_Nod and mark all allocators as either
1482 -- dynamic or static depending on Context_Nod. Any incorrect marking is
1483 -- cleaned up during resolution.
1486 -- Determines if N could be an lvalue (e.g. an assignment left hand side).
1487 -- An lvalue is defined as any expression which appears in a context where
1488 -- a name is required by the syntax, and the identity, rather than merely
1489 -- the value of the node is needed (for example, the prefix of an Access
1490 -- attribute is in this category). Note that, as implied by the name, this
1491 -- test is conservative. If it cannot be sure that N is NOT an lvalue, then
1492 -- it returns True. It tries hard to get the answer right, but it is hard
1493 -- to guarantee this in all cases. Note that it is more possible to give
1494 -- correct answer if the tree is fully analyzed.
1497 -- Return true if Subp must be inlined by the frontend
1500 -- Returns True if a function has defaults for all but its first
1501 -- formal. Used in Ada 2005 mode to solve the syntactic ambiguity that
1502 -- results from an indexing of a function call written in prefix form.
1505 -- Copy recursively an analyzed list of nodes. Uses New_Copy_Tree defined
1506 -- below. As for New_Copy_Tree, it is illegal to attempt to copy extended
1507 -- nodes (entities) either directly or indirectly using this function.
1509 function New_Copy_Tree
1514 -- Given a node that is the root of a subtree, Copy_Tree copies the entire
1515 -- syntactic subtree, including recursively any descendents whose parent
1516 -- field references a copied node (descendents not linked to a copied node
1517 -- by the parent field are not copied, instead the copied tree references
1518 -- the same descendent as the original in this case, which is appropriate
1519 -- for non-syntactic fields such as Etype). The parent pointers in the
1520 -- copy are properly set. Copy_Tree (Empty/Error) returns Empty/Error.
1521 -- The one exception to the rule of not copying semantic fields is that
1522 -- any implicit types attached to the subtree are duplicated, so that
1523 -- the copy contains a distinct set of implicit type entities. Thus this
1524 -- function is used when it is necessary to duplicate an analyzed tree,
1525 -- declared in the same or some other compilation unit. This function is
1526 -- declared here rather than in atree because it uses semantic information
1527 -- in particular concerning the structure of itypes and the generation of
1528 -- public symbols.
1530 -- The Map argument, if set to a non-empty Elist, specifies a set of
1531 -- mappings to be applied to entities in the tree. The map has the form:
1532 --
1533 -- old entity 1
1534 -- new entity to replace references to entity 1
1535 -- old entity 2
1536 -- new entity to replace references to entity 2
1537 -- ...
1538 --
1539 -- The call destroys the contents of Map in this case
1540 --
1541 -- The parameter New_Sloc, if set to a value other than No_Location, is
1542 -- used as the Sloc value for all nodes in the new copy. If New_Sloc is
1543 -- set to its default value No_Location, then the Sloc values of the
1544 -- nodes in the copy are simply copied from the corresponding original.
1545 --
1546 -- The Comes_From_Source indication is unchanged if New_Sloc is set to
1547 -- the default No_Location value, but is reset if New_Sloc is given, since
1548 -- in this case the result clearly is neither a source node or an exact
1549 -- copy of a source node.
1550 --
1551 -- The parameter New_Scope, if set to a value other than Empty, is the
1552 -- value to use as the Scope for any Itypes that are copied. The most
1553 -- typical value for this parameter, if given, is Current_Scope.
1555 function New_External_Entity
1563 -- This function creates an N_Defining_Identifier node for an internal
1564 -- created entity, such as an implicit type or subtype, or a record
1565 -- initialization procedure. The entity name is constructed with a call
1566 -- to New_External_Name (Related_Id, Suffix, Suffix_Index, Prefix), so
1567 -- that the generated name may be referenced as a public entry, and the
1568 -- Is_Public flag is set if needed (using Set_Public_Status). If the
1569 -- entity is for a type or subtype, the size/align fields are initialized
1570 -- to unknown (Uint_0).
1572 function New_Internal_Entity
1577 -- This function is similar to New_External_Entity, except that the
1578 -- name is constructed by New_Internal_Name (Id_Char). This is used
1579 -- when the resulting entity does not have to be referenced as a
1580 -- public entity (and in this case Is_Public is not set).
1584 -- Next_Actual (N) is equivalent to N := Next_Actual (N). Note that we
1585 -- inline this procedural form, but not the functional form that follows.
1588 -- Find next actual parameter in declaration order. As described for
1589 -- First_Actual, this is the next actual in the declaration order, not
1590 -- the call order, so this does not correspond to simply taking the
1591 -- next entry of the Parameter_Associations list. The argument is an
1592 -- actual previously returned by a call to First_Actual or Next_Actual.
1593 -- Note that the result produced is always an expression, not a parameter
1594 -- association node, even if named notation was used.
1596 procedure Normalize_Actuals
1601 -- Reorders lists of actuals according to names of formals, value returned
1602 -- in Success indicates success of reordering. For more details, see body.
1603 -- Errors are reported only if Report is set to True.
1606 -- This routine is called if the sub-expression N maybe the target of
1607 -- an assignment (e.g. it is the left side of an assignment, used as
1608 -- an out parameters, or used as prefixes of access attributes). It
1609 -- sets May_Be_Modified in the associated entity if there is one,
1610 -- taking into account the rule that in the case of renamed objects,
1611 -- it is the flag in the renamed object that must be set.
1612 --
1613 -- The parameter Sure is set True if the modification is sure to occur
1614 -- (e.g. target of assignment, or out parameter), and to False if the
1615 -- modification is only potential (e.g. address of entity taken).
1618 -- Return the accessibility level of the view of the object Obj. For
1619 -- convenience, qualified expressions applied to object names are also
1620 -- allowed as actuals for this function.
1623 -- [Ada 2012: AI05-0125-1]: If S is an inherited dispatching primitive S2,
1624 -- or overrides an inherited dispatching primitive S2, the original
1625 -- corresponding operation of S is the original corresponding operation of
1626 -- S2. Otherwise, it is S itself.
1629 -- N is a pragma node or aspect specification node. This function returns
1630 -- the name of the pragma or aspect in original source form, taking into
1631 -- account possible rewrites, and also cases where a pragma comes from an
1632 -- aspect (in such cases, the name can be different from the pragma name,
1633 -- e.g. a Pre aspect generates a Precondition pragma). This also deals with
1634 -- the presence of 'Class, which results in one of the special names
1635 -- Name_uPre, Name_uPost, Name_uInvariant, or Name_uType_Invariant being
1636 -- returned to represent the corresponding aspects with x'Class names.
1639 -- Subp is the entity for a subprogram call. This function returns True if
1640 -- predicate tests are required for the arguments in this call (this is the
1641 -- normal case). It returns False for special cases where these predicate
1642 -- tests should be skipped (see body for details).
1645 -- Returns True if the names of both entities correspond with matching
1646 -- primitives. This routine includes support for the case in which one
1647 -- or both entities correspond with entities built by Derive_Subprogram
1648 -- with a special name to avoid being overridden (i.e. return true in case
1649 -- of entities with names "nameP" and "name" or vice versa).
1652 -- Returns some private component (if any) of the given Type_Id.
1653 -- Used to enforce the rules on visibility of operations on composite
1654 -- types, that depend on the full view of the component type. For a
1655 -- record type there may be several such components, we just return
1656 -- the first one.
1658 procedure Process_End_Label
1662 -- N is a node whose End_Label is to be processed, generating all
1663 -- appropriate cross-reference entries, and performing style checks
1664 -- for any identifier references in the end label. Typ is either
1665 -- 'e' or 't indicating the type of the cross-reference entity
1666 -- (e for spec, t for body, see Lib.Xref spec for details). The
1667 -- parameter Ent gives the entity to which the End_Label refers,
1668 -- and to which cross-references are to be generated.
1671 -- Determine whether entity Id is referenced within expression Expr
1674 -- Returns True if the expression Expr contains any references to a
1675 -- generic type. This can only happen within a generic template.
1678 -- Removes E from the homonym chain
1681 -- This is used to construct the second argument in a call to Rep_To_Pos
1682 -- which is Standard_True if range checks are enabled (E is an entity to
1683 -- which the Range_Checks_Suppressed test is applied), and Standard_False
1684 -- if range checks are suppressed. Loc is the location for the node that
1685 -- is returned (which is a New_Occurrence of the appropriate entity).
1686 --
1687 -- Note: one might think that it would be fine to always use True and
1688 -- to ignore the suppress in this case, but it is generally better to
1689 -- believe a request to suppress exceptions if possible, and further
1690 -- more there is at least one case in the generated code (the code for
1691 -- array assignment in a loop) that depends on this suppression.
1694 -- N is a node which should have an entity value if it is an entity name.
1695 -- If not, then check if there were previous errors. If so, just fill
1696 -- in with Any_Id and ignore. Otherwise signal a program error exception.
1697 -- This is used as a defense mechanism against ill-formed trees caused by
1698 -- previous errors (particularly in -gnatq mode).
1700 function Requires_State_Refinement
1703 -- Determine whether a package denoted by its spec and body entities
1704 -- requires refinement of abstract states.
1707 -- Id is a type entity. The result is True when temporaries of this type
1708 -- need to be wrapped in a transient scope to be reclaimed properly when a
1709 -- secondary stack is in use. Examples of types requiring such wrapping are
1710 -- controlled types and variable-sized types including unconstrained
1711 -- arrays.
1714 -- Reset the Analyzed flags in all nodes of the tree whose root is N
1717 -- Set the current SPARK_Mode to whatever Mode denotes. This routime must
1718 -- be used in tandem with Save_SPARK_Mode_And_Set.
1721 -- Return true if Subp is a function that returns an unconstrained type
1724 -- Similar to attribute Root_Type, but this version always follows the
1725 -- Full_View of a private type (if available) while searching for the
1726 -- ultimate derivation ancestor.
1728 function Safe_To_Capture_Value
1732 -- The caller is interested in capturing a value (either the current value,
1733 -- or an indication that the value is non-null) for the given entity Ent.
1734 -- This value can only be captured if sequential execution semantics can be
1735 -- properly guaranteed so that a subsequent reference will indeed be sure
1736 -- that this current value indication is correct. The node N is the
1737 -- construct which resulted in the possible capture of the value (this
1738 -- is used to check if we are in a conditional).
1739 --
1740 -- Cond is used to skip the test for being inside a conditional. It is used
1741 -- in the case of capturing values from if/while tests, which already do a
1742 -- proper job of handling scoping issues without this help.
1743 --
1744 -- The only entities whose values can be captured are OUT and IN OUT formal
1745 -- parameters, and variables unless Cond is True, in which case we also
1746 -- allow IN formals, loop parameters and constants, where we cannot ever
1747 -- capture actual value information, but we can capture conditional tests.
1750 -- Determine if two (possibly expanded) names are the same name. This is
1751 -- a purely syntactic test, and N1 and N2 need not be analyzed.
1754 -- Determine if Node1 and Node2 are known to designate the same object.
1755 -- This is a semantic test and both nodes must be fully analyzed. A result
1756 -- of True is decisively correct. A result of False does not necessarily
1757 -- mean that different objects are designated, just that this could not
1758 -- be reliably determined at compile time.
1761 -- Determines if T1 and T2 represent exactly the same type. Two types
1762 -- are the same if they are identical, or if one is an unconstrained
1763 -- subtype of the other, or they are both common subtypes of the same
1764 -- type with identical constraints. The result returned is conservative.
1765 -- It is True if the types are known to be the same, but a result of
1766 -- False is indecisive (e.g. the compiler may not be able to tell that
1767 -- two constraints are identical).
1770 -- Determines if Node1 and Node2 are known to be the same value, which is
1771 -- true if they are both compile time known values and have the same value,
1772 -- or if they are the same object (in the sense of function Same_Object).
1773 -- A result of False does not necessarily mean they have different values,
1774 -- just that it is not possible to determine they have the same value.
1776 procedure Save_SPARK_Mode_And_Set
1779 -- Save the current SPARK_Mode in effect in Mode. Establish the SPARK_Mode
1780 -- (if any) of a package or a subprogram denoted by Context. This routine
1781 -- must be used in tandem with Restore_SPARK_Mode.
1784 -- Tests if type T can be determined at compile time to have at least one
1785 -- scalar part in the sense of the Valid_Scalars attribute. Returns True if
1786 -- this is the case, and False if no scalar parts are present (meaning that
1787 -- the result of Valid_Scalars applied to T is always vacuously True).
1790 -- Determines if the entity Scope1 is the same as Scope2, or if it is
1791 -- inside it, where both entities represent scopes. Note that scopes
1792 -- are only partially ordered, so Scope_Within_Or_Same (A,B) and
1793 -- Scope_Within_Or_Same (B,A) can both be False for a given pair A,B.
1796 -- Like Scope_Within_Or_Same, except that this function returns
1797 -- False in the case where Scope1 and Scope2 are the same scope.
1800 -- Same as Basic_Set_Convention, but with an extra check for access types.
1801 -- In particular, if E is an access-to-subprogram type, and Val is a
1802 -- foreign convention, then we set Can_Use_Internal_Rep to False on E.
1803 -- Also, if the Etype of E is set and is an anonymous access type with
1804 -- no convention set, this anonymous type inherits the convention of E.
1808 -- Establish the entity E as the currently visible definition of its
1809 -- associated name (i.e. the Node_Id associated with its name).
1812 -- Sets the Debug_Info_Needed flag on entity T , and also on any entities
1813 -- that are needed by T (for an object, the type of the object is needed,
1814 -- and for a type, various subsidiary types are needed -- see body for
1815 -- details). Never has any effect on T if the Debug_Info_Off flag is set.
1816 -- This routine should always be used instead of Set_Needs_Debug_Info to
1817 -- ensure that subsidiary entities are properly handled.
1820 -- This procedure has the same calling sequence as Set_Entity, but it
1821 -- performs additional checks as follows:
1822 --
1823 -- If Style_Check is set, then it calls a style checking routine which
1824 -- can check identifier spelling style. This procedure also takes care
1825 -- of checking the restriction No_Implementation_Identifiers.
1826 --
1827 -- If restriction No_Abort_Statements is set, then it checks that the
1828 -- entity is not Ada.Task_Identification.Abort_Task.
1829 --
1830 -- If restriction No_Dynamic_Attachment is set, then it checks that the
1831 -- entity is not one of the restricted names for this restriction.
1832 --
1833 -- If restriction No_Long_Long_Integers is set, then it checks that the
1834 -- entity is not Standard.Long_Long_Integer.
1835 --
1836 -- If restriction No_Implementation_Identifiers is set, then it checks
1837 -- that the entity is not implementation defined.
1841 -- Sets the Entity_Id value associated with the given name, which is the
1842 -- Id of the innermost visible entity with the given name. See the body
1843 -- of package Sem_Ch8 for further details on the handling of visibility.
1846 -- The arguments may be parameter associations, whose descendants
1847 -- are the optional formal name and the actual parameter. Positional
1848 -- parameters are already members of a list, and do not need to be
1849 -- chained separately. See also First_Actual and Next_Actual.
1853 -- Sets Optimize_Alignment_Space/Time flags in E from current settings
1856 -- If an entity (visible or otherwise) is defined in a library
1857 -- package, or a package that is itself public, then this subprogram
1858 -- labels the entity public as well.
1861 -- N is the node for either a left hand side (Out_Param set to False),
1862 -- or an Out or In_Out parameter (Out_Param set to True). If there is
1863 -- an assignable entity being referenced, then the appropriate flag
1864 -- (Referenced_As_LHS if Out_Param is False, Referenced_As_Out_Parameter
1865 -- if Out_Param is True) is set True, and the other flag set False.
1868 -- Set the flag Is_Transient of the current scope
1872 -- Copies the Esize field and Has_Biased_Representation flag from sub(type)
1873 -- entity T2 to (sub)type entity T1. Also copies the Is_Unsigned_Type flag
1874 -- in the fixed-point and discrete cases, and also copies the alignment
1875 -- value from T2 to T1. It does NOT copy the RM_Size field, which must be
1876 -- separately set if this is required to be copied also.
1879 -- True if the current scope is transient
1882 -- This function analyzes the given expression node and then resolves it
1883 -- as Standard.Boolean. If the result is static, then Uint_1 or Uint_0 is
1884 -- returned corresponding to the value, otherwise an error message is
1885 -- output and No_Uint is returned.
1888 -- This function analyzes the given expression node and then resolves it
1889 -- as any integer type. If the result is static, then the value of the
1890 -- universal expression is returned, otherwise an error message is output
1891 -- and a value of No_Uint is returned.
1894 -- Return True if it can be statically determined that the Expressions
1895 -- E1 and E2 refer to different objects
1898 -- Determine whether node N is a loop statement subject to at least one
1899 -- 'Loop_Entry attribute.
1902 -- Return the accessibility level of the view denoted by Subp
1905 -- Return True if Typ supports the GCC built-in atomic operations (i.e. if
1906 -- Typ is properly sized and aligned).
1909 -- Print debugging information on entry to each unit being analyzed
1912 -- Move a list of entities from one scope to another, and recompute
1913 -- Is_Public based upon the new scope.
1916 -- Return the accessibility level of Typ
1918 function Type_Without_Stream_Operation
1921 -- AI05-0161: In Ada 2012, if the restriction No_Default_Stream_Attributes
1922 -- is active then we cannot generate stream subprograms for composite types
1923 -- with elementary subcomponents that lack user-defined stream subprograms.
1924 -- This predicate determines whether a type has such an elementary
1925 -- subcomponent. If Op is TSS_Null, a type that lacks either Read or Write
1926 -- prevents the construction of a composite stream operation. If Op is
1927 -- specified we check only for the given stream operation.
1930 -- Return the entity which represents declaration N, so that different
1931 -- views of the same entity have the same unique defining entity:
1932 -- * package spec and body;
1933 -- * subprogram declaration, subprogram stub and subprogram body;
1934 -- * private view and full view of a type;
1935 -- * private view and full view of a deferred constant.
1936 -- In other cases, return the defining entity for N.
1939 -- Return the unique entity for entity E, which would be returned by
1940 -- Unique_Defining_Entity if applied to the enclosing declaration of E.
1943 -- Return a unique name for entity E, which could be used to identify E
1944 -- across compilation units.
1947 -- Determine whether a compilation unit is visible in the current context,
1948 -- because there is a with_clause that makes the unit available. Used to
1949 -- provide better messages on common visiblity errors on operators.
1952 -- Yields Universal_Integer or Universal_Real if this is a candidate
1956 -- Removes any qualifications from Expr. For example, for T1'(T2'(X)), this
1957 -- returns X. If Expr is not a qualified expression, returns Expr.
1960 -- [Ada 2012:AI-0125-1]: Collect all the visible parents and progenitors
1961 -- of a type extension or private extension declaration. If the full-view
1962 -- of private parents and progenitors is available then it is used to
1963 -- generate the list of visible ancestors; otherwise their partial
1964 -- view is added to the resulting list.
1967 -- Determines if Current_Scope is within an init proc
1970 -- Returns True if entity Id is declared within scope S
1973 -- Output error message for incorrectly typed expression. Expr is the node
1974 -- for the incorrectly typed construct (Etype (Expr) is the type found),
1975 -- and Expected_Type is the entity for the expected type. Note that Expr
1976 -- does not have to be a subexpression, anything with an Etype field may
1977 -- be used.