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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                             S E M _ U T I L                              --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 1992-2011, Free Software Foundation, Inc.         --

--                                                                          --

-- GNAT is free software;  you can  redistribute it  and/or modify it under --

-- terms of the  GNU General Public License as published  by the Free Soft- --

-- ware  Foundation;  either version 3,  or (at your option) any later ver- --

-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --

-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --

-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --

-- for  more details.  You should have  received  a copy of the GNU General --

-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --

-- http://www.gnu.org/licenses for a complete copy of the license.          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

--  Package containing utility procedures used throughout the semantics

with Einfo;   use Einfo;

with Exp_Tss; use Exp_Tss;

with Namet;   use Namet;

with Nmake;   use Nmake;

with Snames;  use Snames;

with Types;   use Types;

with Uintp;   use Uintp;

with Urealp;  use Urealp;

package Sem_Util is

   function Abstract_Interface_List (Typ : Entity_Id) return List_Id;

   --  Given a type that implements interfaces look for its associated

   --  definition node and return its list of interfaces.

   procedure Add_Access_Type_To_Process (E : Entity_Id; A : Entity_Id);

   --  Add A to the list of access types to process when expanding the

   --  freeze node of E.

   procedure Add_Global_Declaration (N : Node_Id);

   --  These procedures adds a declaration N at the library level, to be

   --  elaborated before any other code in the unit. It is used for example

   --  for the entity that marks whether a unit has been elaborated. The

   --  declaration is added to the Declarations list of the Aux_Decls_Node

   --  for the current unit. The declarations are added in the current scope,

   --  so the caller should push a new scope as required before the call.

   function Addressable (V : Uint) return Boolean;

   function Addressable (V : Int)  return Boolean;

   pragma Inline (Addressable);

   --  Returns True if the value of V is the word size of an addressable

   --  factor of the word size (typically 8, 16, 32 or 64).

   function Alignment_In_Bits (E : Entity_Id) return Uint;

   --  If the alignment of the type or object E is currently known to the

   --  compiler, then this function returns the alignment value in bits.

   --  Otherwise Uint_0 is returned, indicating that the alignment of the

   --  entity is not yet known to the compiler.

   procedure Apply_Compile_Time_Constraint_Error

     (N      : Node_Id;

      Msg    : String;

      Reason : RT_Exception_Code;

      Ent    : Entity_Id  := Empty;

      Typ    : Entity_Id  := Empty;

      Loc    : Source_Ptr := No_Location;

      Rep    : Boolean    := True;

      Warn   : Boolean    := False);

   --  N is a subexpression which will raise constraint error when evaluated

   --  at runtime. Msg is a message that explains the reason for raising the

   --  exception. The last character is ? if the message is always a warning,

   --  even in Ada 95, and is not a ? if the message represents an illegality

   --  (because of violation of static expression rules) in Ada 95 (but not

   --  in Ada 83). Typically this routine posts all messages at the Sloc of

   --  node N. However, if Loc /= No_Location, Loc is the Sloc used to output

   --  the message. After posting the appropriate message, and if the flag

   --  Rep is set, this routine replaces the expression with an appropriate

   --  N_Raise_Constraint_Error node using the given Reason code. This node

   --  is then marked as being static if the original node is static, but

   --  sets the flag Raises_Constraint_Error, preventing further evaluation.

   --  The error message may contain a } or & insertion character. This

   --  normally references Etype (N), unless the Ent argument is given

   --  explicitly, in which case it is used instead. The type of the raise

   --  node that is built is normally Etype (N), but if the Typ parameter

   --  is present, this is used instead. Warn is normally False. If it is

   --  True then the message is treated as a warning even though it does

   --  not end with a ? (this is used when the caller wants to parameterize

   --  whether an error or warning is given.

   function Available_Full_View_Of_Component (T : Entity_Id) return Boolean;

   --  If at the point of declaration an array type has a private or limited

   --  component, several array operations are not avaiable on the type, and

   --  the array type is flagged accordingly. If in the immediate scope of

   --  the array type the component becomes non-private or non-limited, these

   --  operations become avaiable. This can happen if the scopes of both types

   --  are open, and the scope of the array is not outside the scope of the

   --  component.

   procedure Bad_Predicated_Subtype_Use

     (Msg : String;

      N   : Node_Id;

      Typ : Entity_Id);

   --  This is called when Typ, a predicated subtype, is used in a context

   --  which does not allow the use of a predicated subtype. Msg is passed

   --  to Error_Msg_FE to output an appropriate message using N as the

   --  location, and Typ as the entity. The caller must set up any insertions

   --  other than the & for the type itself. Note that if Typ is a generic

   --  actual type, then the message will be output as a warning, and a

   --  raise Program_Error is inserted using Insert_Action with node N as

   --  the insertion point. Node N also supplies the source location for

   --  construction of the raise node. If Typ is NOT a type with predicates

   --  this call has no effect.

   function Build_Actual_Subtype

     (T : Entity_Id;

      N : Node_Or_Entity_Id) return Node_Id;

   --  Build an anonymous subtype for an entity or expression, using the

   --  bounds of the entity or the discriminants of the enclosing record.

   --  T is the type for which the actual subtype is required, and N is either

   --  a defining identifier, or any subexpression.

   function Build_Actual_Subtype_Of_Component

     (T : Entity_Id;

      N : Node_Id) return Node_Id;

   --  Determine whether a selected component has a type that depends on

   --  discriminants, and build actual subtype for it if so.

   function Build_Default_Subtype

     (T : Entity_Id;

      N : Node_Id) return Entity_Id;

   --  If T is an unconstrained type with defaulted discriminants, build a

   --  subtype constrained by the default values, insert the subtype

   --  declaration in the tree before N, and return the entity of that

   --  subtype. Otherwise, simply return T.

   function Build_Discriminal_Subtype_Of_Component

     (T : Entity_Id) return Node_Id;

   --  Determine whether a record component has a type that depends on

   --  discriminants, and build actual subtype for it if so.

   procedure Build_Elaboration_Entity (N : Node_Id; Spec_Id : Entity_Id);

   --  Given a compilation unit node N, allocate an elaboration counter for

   --  the compilation unit, and install it in the Elaboration_Entity field

   --  of Spec_Id, the entity for the compilation unit.

      procedure Build_Explicit_Dereference

        (Expr : Node_Id;

         Disc : Entity_Id);

      --  AI05-139: Names with implicit dereference. If the expression N is a

      --  reference type and the context imposes the corresponding designated

      --  type, convert N into N.Disc.all. Such expressions are always over-

      --  loaded with both interpretations, and the dereference interpretation

      --  carries the name of the reference discriminant.

   function Cannot_Raise_Constraint_Error (Expr : Node_Id) return Boolean;

   --  Returns True if the expression cannot possibly raise Constraint_Error.

   --  The response is conservative in the sense that a result of False does

   --  not necessarily mean that CE could be raised, but a response of True

   --  means that for sure CE cannot be raised.

   procedure Check_Implicit_Dereference (Nam : Node_Id; Typ : Entity_Id);

   --  AI05-139-2: Accessors and iterators for containers. This procedure

   --  checks whether T is a reference type, and if so it adds an interprettion

   --  to Expr whose type is the designated type of the reference_discriminant.

   procedure Check_Later_Vs_Basic_Declarations

     (Decls          : List_Id;

      During_Parsing : Boolean);

   --  If During_Parsing is True, check for misplacement of later vs basic

   --  declarations in Ada 83. If During_Parsing is False, and the SPARK

   --  restriction is set, do the same: although SPARK 95 removes the

   --  distinction between initial and later declarative items, the distinction

   --  remains in the Examiner (JB01-005). Note that the Examiner does not

   --  count package declarations in later declarative items.

   procedure Check_Dynamically_Tagged_Expression

     (Expr        : Node_Id;

      Typ         : Entity_Id;

      Related_Nod : Node_Id);

   --  Check wrong use of dynamically tagged expression

   procedure Check_Fully_Declared (T : Entity_Id; N : Node_Id);

   --  Verify that the full declaration of type T has been seen. If not, place

   --  error message on node N. Used in object declarations, type conversions

   --  and qualified expressions.

   procedure Check_Nested_Access (Ent : Entity_Id);

   --  Check whether Ent denotes an entity declared in an uplevel scope, which

   --  is accessed inside a nested procedure, and set Has_Up_Level_Access flag

   --  accordingly. This is currently only enabled for VM_Target /= No_VM.

   procedure Check_Order_Dependence;

   --  Examine the actuals in a top-level call to determine whether aliasing

   --  between two actuals, one of which is writable, can make the call

   --  order-dependent.

   procedure Check_Potentially_Blocking_Operation (N : Node_Id);

   --  N is one of the statement forms that is a potentially blocking

   --  operation. If it appears within a protected action, emit warning.

   procedure Check_Unprotected_Access

     (Context : Node_Id;

      Expr    : Node_Id);

   --  Check whether the expression is a pointer to a protected component,

   --  and the context is external to the protected operation, to warn against

   --  a possible unlocked access to data.

   procedure Check_VMS (Construct : Node_Id);

   --  Check that this the target is OpenVMS, and if so, return with no effect,

   --  otherwise post an error noting this can only be used with OpenVMS ports.

   --  The argument is the construct in question and is used to post the error

   --  message.

   procedure Collect_Interfaces

     (T               : Entity_Id;

      Ifaces_List     : out Elist_Id;

      Exclude_Parents : Boolean := False;

      Use_Full_View   : Boolean := True);

   --  Ada 2005 (AI-251): Collect whole list of abstract interfaces that are

   --  directly or indirectly implemented by T. Exclude_Parents is used to

   --  avoid the addition of inherited interfaces to the generated list.

   --  Use_Full_View is used to collect the interfaces using the full-view

   --  (if available).

   procedure Collect_Interface_Components

     (Tagged_Type     : Entity_Id;

      Components_List : out Elist_Id);

   --  Ada 2005 (AI-251): Collect all the tag components associated with the

   --  secondary dispatch tables of a tagged type.

   procedure Collect_Interfaces_Info

     (T               : Entity_Id;

      Ifaces_List     : out Elist_Id;

      Components_List : out Elist_Id;

      Tags_List       : out Elist_Id);

   --  Ada 2005 (AI-251): Collect all the interfaces associated with T plus

   --  the record component and tag associated with each of these interfaces.

   --  On exit Ifaces_List, Components_List and Tags_List have the same number

   --  of elements, and elements at the same position on these tables provide

   --  information on the same interface type.

   procedure Collect_Parents

     (T             : Entity_Id;

      List          : out Elist_Id;

      Use_Full_View : Boolean := True);

   --  Collect all the parents of Typ. Use_Full_View is used to collect them

   --  using the full-view of private parents (if available).

   function Collect_Primitive_Operations (T : Entity_Id) return Elist_Id;

   --  Called upon type derivation and extension. We scan the declarative part

   --  in which the type appears, and collect subprograms that have one

   --  subsidiary subtype of the type. These subprograms can only appear after

   --  the type itself.

   function Compile_Time_Constraint_Error

     (N    : Node_Id;

      Msg  : String;

      Ent  : Entity_Id  := Empty;

      Loc  : Source_Ptr := No_Location;

      Warn : Boolean    := False) return Node_Id;

   --  This is similar to Apply_Compile_Time_Constraint_Error in that it

   --  generates a warning (or error) message in the same manner, but it does

   --  not replace any nodes. For convenience, the function always returns its

   --  first argument. The message is a warning if the message ends with ?, or

   --  we are operating in Ada 83 mode, or the Warn parameter is set to True.

   procedure Conditional_Delay (New_Ent, Old_Ent : Entity_Id);

   --  Sets the Has_Delayed_Freeze flag of New if the Delayed_Freeze flag of

   --  Old is set and Old has no yet been Frozen (i.e. Is_Frozen is false).

   function Copy_Parameter_List (Subp_Id : Entity_Id) return List_Id;

   --  Utility to create a parameter profile for a new subprogram spec, when

   --  the subprogram has a body that acts as spec. This is done for some cases

   --  of inlining, and for private protected ops. Also used to create bodies

   --  for stubbed subprograms.

   function Copy_Component_List

     (R_Typ : Entity_Id;

      Loc   : Source_Ptr) return List_Id;

   --  Copy components from record type R_Typ that come from source. Used to

   --  create a new compatible record type. Loc is the source location assigned

   --  to the created nodes.

   function Current_Entity (N : Node_Id) return Entity_Id;

   pragma Inline (Current_Entity);

   --  Find the currently visible definition for a given identifier, that is to

   --  say the first entry in the visibility chain for the Chars of N.

   function Current_Entity_In_Scope (N : Node_Id) return Entity_Id;

   --  Find whether there is a previous definition for identifier N in the

   --  current scope. Because declarations for a scope are not necessarily

   --  contiguous (e.g. for packages) the first entry on the visibility chain

   --  for N is not necessarily in the current scope.

   function Current_Scope return Entity_Id;

   --  Get entity representing current scope

   function Current_Subprogram return Entity_Id;

   --  Returns current enclosing subprogram. If Current_Scope is a subprogram,

   --  then that is what is returned, otherwise the Enclosing_Subprogram of the

   --  Current_Scope is returned. The returned value is Empty if this is called

   --  from a library package which is not within any subprogram.

   function Deepest_Type_Access_Level (Typ : Entity_Id) return Uint;

   --  Same as Type_Access_Level, except that if the type is the type of an Ada

   --  2012 stand-alone object of an anonymous access type, then return the

   --  static accesssibility level of the object. In that case, the dynamic

   --  accessibility level of the object may take on values in a range. The low

   --  bound of of that range is returned by Type_Access_Level; this function

   --  yields the high bound of that range. Also differs from Type_Access_Level

   --  in the case of a descendant of a generic formal type (returns Int'Last

   --  instead of 0).

   function Defining_Entity (N : Node_Id) return Entity_Id;

   --  Given a declaration N, returns the associated defining entity. If the

   --  declaration has a specification, the entity is obtained from the

   --  specification. If the declaration has a defining unit name, then the

   --  defining entity is obtained from the defining unit name ignoring any

   --  child unit prefixes.

   function Denotes_Discriminant

     (N                : Node_Id;

      Check_Concurrent : Boolean := False) return Boolean;

   --  Returns True if node N is an Entity_Name node for a discriminant. If the

   --  flag Check_Concurrent is true, function also returns true when N denotes

   --  the discriminal of the discriminant of a concurrent type. This is needed

   --  to disable some optimizations on private components of protected types,

   --  and constraint checks on entry families constrained by discriminants.

   function Denotes_Same_Object (A1, A2 : Node_Id) return Boolean;

   function Denotes_Same_Prefix (A1, A2 : Node_Id) return Boolean;

   --  Functions to detect suspicious overlapping between actuals in a call,

   --  when one of them is writable. The predicates are those proposed in

   --  AI05-0144, to detect dangerous order dependence in complex calls.

   --  I would add a parameter Warn which enables more extensive testing of

   --  cases as we find appropriate when we are only warning ??? Or perhaps

   --  return an indication of (Error, Warn, OK) ???

   function Denotes_Variable (N : Node_Id) return Boolean;

   --  Returns True if node N denotes a single variable without parentheses

   function Depends_On_Discriminant (N : Node_Id) return Boolean;

   --  Returns True if N denotes a discriminant or if N is a range, a subtype

   --  indication or a scalar subtype where one of the bounds is a

   --  discriminant.

   function Designate_Same_Unit

     (Name1 : Node_Id;

      Name2 : Node_Id) return  Boolean;

   --  Return true if Name1 and Name2 designate the same unit name; each of

   --  these names is supposed to be a selected component name, an expanded

   --  name, a defining program unit name or an identifier.

   function Dynamic_Accessibility_Level (Expr : Node_Id) return Node_Id;

   --  Expr should be an expression of an access type. Builds an integer

   --  literal except in cases involving anonymous access types where

   --  accessibility levels are tracked at runtime (access parameters and Ada

   --  2012 stand-alone objects).

   function Effective_Extra_Accessibility (Id : Entity_Id) return Entity_Id;

   --  Same as Einfo.Extra_Accessibility except thtat object renames

   --  are looked through.

   function Enclosing_CPP_Parent (Typ : Entity_Id) return Entity_Id;

   --  Returns the closest ancestor of Typ that is a CPP type.

   function Enclosing_Generic_Body

     (N : Node_Id) return Node_Id;

   --  Returns the Node_Id associated with the innermost enclosing generic

   --  body, if any. If none, then returns Empty.

   function Enclosing_Generic_Unit

     (N : Node_Id) return Node_Id;

   --  Returns the Node_Id associated with the innermost enclosing generic

   --  unit, if any. If none, then returns Empty.

   function Enclosing_Lib_Unit_Entity return Entity_Id;

   --  Returns the entity of enclosing N_Compilation_Unit Node which is the

   --  root of the current scope (which must not be Standard_Standard, and the

   --  caller is responsible for ensuring this condition).

   function Enclosing_Lib_Unit_Node (N : Node_Id) return Node_Id;

   --  Returns the enclosing N_Compilation_Unit Node that is the root of a

   --  subtree containing N.

   function Enclosing_Package (E : Entity_Id) return Entity_Id;

   --  Utility function to return the Ada entity of the package enclosing

   --  the entity E, if any. Returns Empty if no enclosing package.

   function Enclosing_Subprogram (E : Entity_Id) return Entity_Id;

   --  Utility function to return the Ada entity of the subprogram enclosing

   --  the entity E, if any. Returns Empty if no enclosing subprogram.

   procedure Ensure_Freeze_Node (E : Entity_Id);

   --  Make sure a freeze node is allocated for entity E. If necessary, build

   --  and initialize a new freeze node and set Has_Delayed_Freeze True for E.

   procedure Enter_Name (Def_Id : Entity_Id);

   --  Insert new name in symbol table of current scope with check for

   --  duplications (error message is issued if a conflict is found).

   --  Note: Enter_Name is not used for overloadable entities, instead these

   --  are entered using Sem_Ch6.Enter_Overloadable_Entity.

   procedure Explain_Limited_Type (T : Entity_Id; N : Node_Id);

   --  This procedure is called after issuing a message complaining about an

   --  inappropriate use of limited type T. If useful, it adds additional

   --  continuation lines to the message explaining why type T is limited.

   --  Messages are placed at node N.

   procedure Find_Actual

     (N      : Node_Id;

      Formal : out Entity_Id;

      Call   : out Node_Id);

   --  Determines if the node N is an actual parameter of a function of a

   --  procedure call. If so, then Formal points to the entity for the formal

   --  (Ekind is E_In_Parameter, E_Out_Parameter, or E_In_Out_Parameter) and

   --  Call is set to the node for the corresponding call. If the node N is not

   --  an actual parameter then Formal and Call are set to Empty.

   function Find_Corresponding_Discriminant

     (Id   : Node_Id;

      Typ  : Entity_Id) return Entity_Id;

   --  Because discriminants may have different names in a generic unit and in

   --  an instance, they are resolved positionally when possible. A reference

   --  to a discriminant carries the discriminant that it denotes when it is

   --  analyzed. Subsequent uses of this id on a different type denotes the

   --  discriminant at the same position in this new type.

   procedure Find_Overlaid_Entity

     (N : Node_Id;

      Ent : out Entity_Id;

      Off : out Boolean);

   --  The node N should be an address representation clause. Determines if

   --  the target expression is the address of an entity with an optional

   --  offset. If so, set Ent to the entity and, if there is an offset, set

   --  Off to True, otherwise to False. If N is not an address representation

   --  clause, or if it is not possible to determine that the address is of

   --  this form, then set Ent to Empty.

   function Find_Parameter_Type (Param : Node_Id) return Entity_Id;

   --  Return the type of formal parameter Param as determined by its

   --  specification.

   function Find_Static_Alternative (N : Node_Id) return Node_Id;

   --  N is a case statement whose expression is a compile-time value.

   --  Determine the alternative chosen, so that the code of non-selected

   --  alternatives, and the warnings that may apply to them, are removed.

   function Find_Body_Discriminal

     (Spec_Discriminant : Entity_Id) return Entity_Id;

   --  Given a discriminant of the record type that implements a task or

   --  protected type, return the discriminal of the corresponding discriminant

   --  of the actual concurrent type.

   function First_Actual (Node : Node_Id) return Node_Id;

   --  Node is an N_Function_Call or N_Procedure_Call_Statement node. The

   --  result returned is the first actual parameter in declaration order

   --  (not the order of parameters as they appeared in the source, which

   --  can be quite different as a result of the use of named parameters).

   --  Empty is returned for a call with no parameters. The procedure for

   --  iterating through the actuals in declaration order is to use this

   --  function to find the first actual, and then use Next_Actual to obtain

   --  the next actual in declaration order. Note that the value returned

   --  is always the expression (not the N_Parameter_Association nodes,

   --  even if named association is used).

   procedure Gather_Components

     (Typ           : Entity_Id;

      Comp_List     : Node_Id;

      Governed_By   : List_Id;

      Into          : Elist_Id;

      Report_Errors : out Boolean);

   --  The purpose of this procedure is to gather the valid components in a

   --  record type according to the values of its discriminants, in order to

   --  validate the components of a record aggregate.

   --

   --    Typ is the type of the aggregate when its constrained discriminants

   --      need to be collected, otherwise it is Empty.

   --

   --    Comp_List is an N_Component_List node.

   --

   --    Governed_By is a list of N_Component_Association nodes, where each

   --     choice list contains the name of a discriminant and the expression

   --     field gives its value. The values of the discriminants governing

   --     the (possibly nested) variant parts in Comp_List are found in this

   --     Component_Association List.

   --

   --    Into is the list where the valid components are appended. Note that

   --     Into need not be an Empty list. If it's not, components are attached

   --     to its tail.

   --

   --    Report_Errors is set to True if the values of the discriminants are

   --     non-static.

   --

   --  This procedure is also used when building a record subtype. If the

   --  discriminant constraint of the subtype is static, the components of the

   --  subtype are only those of the variants selected by the values of the

   --  discriminants. Otherwise all components of the parent must be included

   --  in the subtype for semantic analysis.

   function Get_Actual_Subtype (N : Node_Id) return Entity_Id;

   --  Given a node for an expression, obtain the actual subtype of the

   --  expression. In the case of a parameter where the formal is an

   --  unconstrained array or discriminated type, this will be the previously

   --  constructed subtype of the actual. Note that this is not quite the

   --  "Actual Subtype" of the RM, since it is always a constrained type, i.e.

   --  it is the subtype of the value of the actual. The actual subtype is also

   --  returned in other cases where it has already been constructed for an

   --  object. Otherwise the expression type is returned unchanged, except for

   --  the case of an unconstrained array type, where an actual subtype is

   --  created, using Insert_Actions if necessary to insert any associated

   --  actions.

   function Get_Actual_Subtype_If_Available (N : Node_Id) return Entity_Id;

   --  This is like Get_Actual_Subtype, except that it never constructs an

   --  actual subtype. If an actual subtype is already available, i.e. the

   --  Actual_Subtype field of the corresponding entity is set, then it is

   --  returned. Otherwise the Etype of the node is returned.

   function Get_Body_From_Stub (N : Node_Id) return Node_Id;

   --  Return the body node for a stub (subprogram or package)

   function Get_Default_External_Name (E : Node_Or_Entity_Id) return Node_Id;

   --  This is used to construct the string literal node representing a

   --  default external name, i.e. one that is constructed from the name of an

   --  entity, or (in the case of extended DEC import/export pragmas, an

   --  identifier provided as the external name. Letters in the name are

   --  according to the setting of Opt.External_Name_Default_Casing.

   function Get_Enclosing_Object (N : Node_Id) return Entity_Id;

   --  If expression N references a part of an object, return this object.

   --  Otherwise return Empty. Expression N should have been resolved already.

   function Get_Ensures_From_Test_Case_Pragma (N : Node_Id) return Node_Id;

   --  Return the Ensures component of Test_Case pragma N, or Empty otherwise

   function Get_Generic_Entity (N : Node_Id) return Entity_Id;

   --  Returns the true generic entity in an instantiation. If the name in the

   --  instantiation is a renaming, the function returns the renamed generic.

   procedure Get_Index_Bounds (N : Node_Id; L, H : out Node_Id);

   --  This procedure assigns to L and H respectively the values of the low and

   --  high bounds of node N, which must be a range, subtype indication, or the

   --  name of a scalar subtype. The result in L, H may be set to Error if

   --  there was an earlier error in the range.

   function Get_Enum_Lit_From_Pos

     (T   : Entity_Id;

      Pos : Uint;

      Loc : Source_Ptr) return Node_Id;

   --  This function returns an identifier denoting the E_Enumeration_Literal

   --  entity for the specified value from the enumeration type or subtype T.

   --  The second argument is the Pos value, which is assumed to be in range.

   --  The third argument supplies a source location for constructed nodes

   --  returned by this function.

   procedure Get_Library_Unit_Name_String (Decl_Node : Node_Id);

   --  Retrieve the fully expanded name of the library unit declared by

   --  Decl_Node into the name buffer.

   function Get_Name_Entity_Id (Id : Name_Id) return Entity_Id;

   pragma Inline (Get_Name_Entity_Id);

   --  An entity value is associated with each name in the name table. The

   --  Get_Name_Entity_Id function fetches the Entity_Id of this entity, which

   --  is the innermost visible entity with the given name. See the body of

   --  Sem_Ch8 for further details on handling of entity visibility.

   function Get_Name_From_Test_Case_Pragma (N : Node_Id) return String_Id;

   --  Return the Name component of Test_Case pragma N

   function Get_Pragma_Id (N : Node_Id) return Pragma_Id;

   pragma Inline (Get_Pragma_Id);

   --  Obtains the Pragma_Id from the Chars field of Pragma_Identifier (N)

   function Get_Referenced_Object (N : Node_Id) return Node_Id;

   --  Given a node, return the renamed object if the node represents a renamed

   --  object, otherwise return the node unchanged. The node may represent an

   --  arbitrary expression.

   function Get_Renamed_Entity (E : Entity_Id) return Entity_Id;

   --  Given an entity for an exception, package, subprogram or generic unit,

   --  returns the ultimately renamed entity if this is a renaming. If this is

   --  not a renamed entity, returns its argument. It is an error to call this

   --  with any other kind of entity.

   function Get_Requires_From_Test_Case_Pragma (N : Node_Id) return Node_Id;

   --  Return the Requires component of Test_Case pragma N, or Empty otherwise

   function Get_Subprogram_Entity (Nod : Node_Id) return Entity_Id;

   --  Nod is either a procedure call statement, or a function call, or an

   --  accept statement node. This procedure finds the Entity_Id of the related

   --  subprogram or entry and returns it, or if no subprogram can be found,

   --  returns Empty.

   function Get_Subprogram_Body (E : Entity_Id) return Node_Id;

   --  Given the entity for a subprogram (E_Function or E_Procedure), return

   --  the corresponding N_Subprogram_Body node. If the corresponding body

   --  is missing (as for an imported subprogram), return Empty.

   function Get_Task_Body_Procedure (E : Entity_Id) return Node_Id;

   pragma Inline (Get_Task_Body_Procedure);

   --  Given an entity for a task type or subtype, retrieves the

   --  Task_Body_Procedure field from the corresponding task type declaration.

   function Has_Access_Values (T : Entity_Id) return Boolean;

   --  Returns true if type or subtype T is an access type, or has a component

   --  (at any recursive level) that is an access type. This is a conservative

   --  predicate, if it is not known whether or not T contains access values

   --  (happens for generic formals in some cases), then False is returned.

   --  Note that tagged types return False. Even though the tag is implemented

   --  as an access type internally, this function tests only for access types

   --  known to the programmer. See also Has_Tagged_Component.

   type Alignment_Result is (Known_Compatible, Unknown, Known_Incompatible);

   --  Result of Has_Compatible_Alignment test, description found below. Note

   --  that the values are arranged in increasing order of problematicness.

   function Has_Compatible_Alignment

     (Obj  : Entity_Id;

      Expr : Node_Id) return Alignment_Result;

   --  Obj is an object entity, and expr is a node for an object reference. If

   --  the alignment of the object referenced by Expr is known to be compatible

   --  with the alignment of Obj (i.e. is larger or the same), then the result

   --  is Known_Compatible. If the alignment of the object referenced by Expr

   --  is known to be less than the alignment of Obj, then Known_Incompatible

   --  is returned. If neither condition can be reliably established at compile

   --  time, then Unknown is returned. This is used to determine if alignment

   --  checks are required for address clauses, and also whether copies must

   --  be made when objects are passed by reference.

   --

   --  Note: Known_Incompatible does not mean that at run time the alignment

   --  of Expr is known to be wrong for Obj, just that it can be determined

   --  that alignments have been explicitly or implicitly specified which are

   --  incompatible (whereas Unknown means that even this is not known). The

   --  appropriate reaction of a caller to Known_Incompatible is to treat it as

   --  Unknown, but issue a warning that there may be an alignment error.

   function Has_Declarations (N : Node_Id) return Boolean;

   --  Determines if the node can have declarations

   function Has_Discriminant_Dependent_Constraint

     (Comp : Entity_Id) return Boolean;

   --  Returns True if and only if Comp has a constrained subtype that depends

   --  on a discriminant.

   function Has_Infinities (E : Entity_Id) return Boolean;

   --  Determines if the range of the floating-point type E includes

   --  infinities. Returns False if E is not a floating-point type.

   function Has_Interfaces

     (T             : Entity_Id;

      Use_Full_View : Boolean := True) return Boolean;

   --  Where T is a concurrent type or a record type, returns true if T covers

   --  any abstract interface types. In case of private types the argument

   --  Use_Full_View controls if the check is done using its full view (if

   --  available).

   function Has_Null_Exclusion (N : Node_Id) return Boolean;

   --  Determine whether node N has a null exclusion

   function Has_Overriding_Initialize (T : Entity_Id) return Boolean;

   --  Predicate to determine whether a controlled type has a user-defined

   --  Initialize primitive (and, in Ada 2012, whether that primitive is

   --  non-null), which causes the type to not have preelaborable

   --  initialization.

   function Has_Preelaborable_Initialization (E : Entity_Id) return Boolean;

   --  Return True iff type E has preelaborable initialization as defined in

   --  Ada 2005 (see AI-161 for details of the definition of this attribute).

   function Has_Private_Component (Type_Id : Entity_Id) return Boolean;

   --  Check if a type has a (sub)component of a private type that has not

   --  yet received a full declaration.

   function Has_Static_Array_Bounds (Typ : Node_Id) return Boolean;

   --  Return whether an array type has static bounds

   function Has_Stream (T : Entity_Id) return Boolean;

   --  Tests if type T is derived from Ada.Streams.Root_Stream_Type, or in the

   --  case of a composite type, has a component for which this predicate is

   --  True, and if so returns True. Otherwise a result of False means that

   --  there is no Stream type in sight. For a private type, the test is

   --  applied to the underlying type (or returns False if there is no

   --  underlying type).

   function Has_Suffix (E : Entity_Id; Suffix : Character) return Boolean;

   --  Returns true if the last character of E is Suffix. Used in Assertions.

   function Add_Suffix (E : Entity_Id; Suffix : Character) return Name_Id;

   --  Returns the name of E adding Suffix

   function Remove_Suffix (E : Entity_Id; Suffix : Character) return Name_Id;

   --  Returns the name of E without Suffix

   function Has_Tagged_Component (Typ : Entity_Id) return Boolean;

   --  Returns True if Typ is a composite type (array or record) which is

   --  either itself a tagged type, or has a component (recursively) which is

   --  a tagged type. Returns False for non-composite type, or if no tagged

   --  component is present. This function is used to check if "=" has to be

   --  expanded into a bunch component comparisons.

   function Implementation_Kind (Subp : Entity_Id) return Name_Id;

   --  Subp is a subprogram marked with pragma Implemented. Return the specific

   --  implementation requirement which the pragma imposes. The return value is

   --  either Name_By_Any, Name_By_Entry or Name_By_Protected_Procedure.

   function Implements_Interface

     (Typ_Ent         : Entity_Id;

      Iface_Ent       : Entity_Id;

      Exclude_Parents : Boolean := False) return Boolean;

   --  Returns true if the Typ_Ent implements interface Iface_Ent

   function In_Instance return Boolean;

   --  Returns True if the current scope is within a generic instance

   function In_Instance_Body return Boolean;

   --  Returns True if current scope is within the body of an instance, where

   --  several semantic checks (e.g. accessibility checks) are relaxed.

   function In_Instance_Not_Visible return Boolean;

   --  Returns True if current scope is with the private part or the body of

   --  an instance. Other semantic checks are suppressed in this context.

   function In_Instance_Visible_Part return Boolean;

   --  Returns True if current scope is within the visible part of a package

   --  instance, where several additional semantic checks apply.

   function In_Package_Body return Boolean;

   --  Returns True if current scope is within a package body

   function In_Parameter_Specification (N : Node_Id) return Boolean;

   --  Returns True if node N belongs to a parameter specification

   function In_Subprogram_Or_Concurrent_Unit return Boolean;

   --  Determines if the current scope is within a subprogram compilation unit

   --  (inside a subprogram declaration, subprogram body, or generic

   --  subprogram declaration) or within a task or protected body. The test is

   --  for appearing anywhere within such a construct (that is it does not need

   --  to be directly within).

   function In_Visible_Part (Scope_Id : Entity_Id) return Boolean;

   --  Determine whether a declaration occurs within the visible part of a

   --  package specification. The package must be on the scope stack, and the

   --  corresponding private part must not.

   function Incomplete_Or_Private_View (Typ : Entity_Id) return Entity_Id;

   --  Given the entity of a type, retrieve the incomplete or private view of

   --  the same type. Note that Typ may not have a partial view to begin with,

   --  in that case the function returns Empty.

   procedure Insert_Explicit_Dereference (N : Node_Id);

   --  In a context that requires a composite or subprogram type and where a

   --  prefix is an access type, rewrite the access type node N (which is the

   --  prefix, e.g. of an indexed component) as an explicit dereference.

   procedure Inspect_Deferred_Constant_Completion (Decls : List_Id);

   --  Examine all deferred constants in the declaration list Decls and check

   --  whether they have been completed by a full constant declaration or an

   --  Import pragma. Emit the error message if that is not the case.

   function Is_Actual_Out_Parameter (N : Node_Id) return Boolean;

   --  Determines if N is an actual parameter of out mode in a subprogram call

   function Is_Actual_Parameter (N : Node_Id) return Boolean;

   --  Determines if N is an actual parameter in a subprogram call

   function Is_Actual_Tagged_Parameter (N : Node_Id) return Boolean;

   --  Determines if N is an actual parameter of a formal of tagged type in a

   --  subprogram call.

   function Is_Aliased_View (Obj : Node_Id) return Boolean;

   --  Determine if Obj is an aliased view, i.e. the name of an object to which

   --  'Access or 'Unchecked_Access can apply. Note that this routine uses the

   --  rules of the language, it does not take into account the restriction

   --  No_Implicit_Aliasing, so it can return True if the restriction is active

   --  and Obj violates the restriction. The caller is responsible for calling

   --  Restrict.Check_No_Implicit_Aliasing if True is returned, but there is a

   --  requirement for obeying the restriction in the call context.

   function Is_Ancestor_Package

     (E1 : Entity_Id;

      E2 : Entity_Id) return Boolean;

   --  Determine whether package E1 is an ancestor of E2

   function Is_Atomic_Object (N : Node_Id) return Boolean;

   --  Determines if the given node denotes an atomic object in the sense of

   --  the legality checks described in RM C.6(12).

   function Is_Controlling_Limited_Procedure

     (Proc_Nam : Entity_Id) return Boolean;

   --  Ada 2005 (AI-345): Determine whether Proc_Nam is a primitive procedure

   --  of a limited interface with a controlling first parameter.

   function Is_CPP_Constructor_Call (N : Node_Id) return Boolean;

   --  Returns True if N is a call to a CPP constructor