gcc/ada/sem_ch8.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              S E M _ C H 8                               --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                                                                          --
  10 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- GNAT was originally developed  by the GNAT team at  New York University. --
  24 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  25 --                                                                          --
  26 ------------------------------------------------------------------------------
  27
  28 with Types; use Types;
  29 package Sem_Ch8 is
  30
  31    -----------------------------------
  32    -- Handling extensions of System --
  33    -----------------------------------
  34
  35    --  For targets that define a much larger System package than given in
  36    --  the RM, we use a child package containing additional declarations,
  37    --  which is loaded when needed, and whose entities are conceptually
  38    --  within System itself. The presence of this auxiliary package is
  39    --  controlled with the pragma Extend_System. The following variable
  40    --  holds the entity of the auxiliary package, to simplify the special
  41    --  visibility rules that apply to it.
  42
  43    System_Aux_Id : Entity_Id := Empty;
  44
  45    -----------------
  46    -- Subprograms --
  47    -----------------
  48
  49    procedure Analyze_Exception_Renaming                 (N : Node_Id);
  50    procedure Analyze_Expanded_Name                      (N : Node_Id);
  51    procedure Analyze_Generic_Function_Renaming          (N : Node_Id);
  52    procedure Analyze_Generic_Package_Renaming           (N : Node_Id);
  53    procedure Analyze_Generic_Procedure_Renaming         (N : Node_Id);
  54    procedure Analyze_Object_Renaming                    (N : Node_Id);
  55    procedure Analyze_Package_Renaming                   (N : Node_Id);
  56    procedure Analyze_Subprogram_Renaming                (N : Node_Id);
  57    procedure Analyze_Use_Package                        (N : Node_Id);
  58    procedure Analyze_Use_Type                           (N : Node_Id);
  59
  60    function Applicable_Use (Pack_Name : Node_Id) return Boolean;
  61    --  Common code to Use_One_Package and Set_Use, to determine whether
  62    --  use clause must be processed. Pack_Name is an entity name that
  63    --  references the package in question.
  64
  65    procedure End_Scope;
  66    --  Called at end of scope. On exit from blocks and bodies (subprogram,
  67    --  package, task, and protected bodies), the name of the current scope
  68    --  must be removed from the scope stack, and the local entities must be
  69    --  removed from their homonym chains. On exit from record declarations,
  70    --  from package specifications, and from tasks and protected type
  71    --  specifications, more specialized procedures are invoked.
  72
  73    procedure End_Use_Clauses (Clause : Node_Id);
  74    --  Invoked on scope exit, to undo the effect of local use clauses. U is
  75    --  the first Use clause of a scope being exited. This can be the current
  76    --  scope, or some enclosing scopes when building a clean environment to
  77    --  compile an instance body for inlining.
  78
  79    procedure End_Use_Package (N : Node_Id);
  80    procedure End_Use_Type    (N : Node_Id);
  81    --  Subsidiaries of End_Use_Clauses.  Also called directly for use clauses
  82    --  appearing in context clauses.
  83
  84    procedure Find_Direct_Name (N : Node_Id);
  85    --  Given a direct name (Identifier or Operator_Symbol), this routine
  86    --  scans the homonym chain for the name searching for corresponding
  87    --  visible entities to find the referenced entity (or in the case of
  88    --  overloading), entities. On return, the Entity, and Etype fields
  89    --  are set. In the non-overloaded case, these are the correct final
  90    --  entries. In the overloaded case, Is_Overloaded is set, Etype and
  91    --  Entity refer to an arbitrary element of the overloads set, and
  92    --  an appropriate list of entries has been made in the overload
  93    --  interpretation table (to be disambiguated in the resolve phase).
  94
  95    procedure Find_Expanded_Name (N : Node_Id);
  96    --  Selected component is known to be expanded name. Verify legality
  97    --  of selector given the scope denoted by prefix.
  98
  99    procedure Find_Selected_Component (N : Node_Id);
 100    --  Resolve various cases of selected components, recognize expanded names
 101
 102    procedure Find_Type (N : Node_Id);
 103    --  Perform name resolution, and verify that the name found is that of a
 104    --  type. On return the Entity and Etype fields of the node N are set
 105    --  appropriately. If it is an incomplete type whose full declaration has
 106    --  been seen, return the entity in the full declaration. Similarly, if
 107    --  the type is private, it has receivd a full declaration, and we are
 108    --  in the private part or body of the package, return the full
 109    --  declaration as well. Special processing for Class types as well.
 110
 111    function Get_Full_View (T_Name : Entity_Id) return Entity_Id;
 112    --  If T_Name is an incomplete type and the full declaration has been
 113    --  seen, or is the name of a class_wide type whose root is incomplete.
 114    --  return the corresponding full declaration.
 115
 116    function Has_Implicit_Operator (N : Node_Id) return Boolean;
 117    --  N is an expanded name whose selector is an operator name (eg P."+").
 118    --  A declarative part contains an implicit declaration of an operator
 119    --  if it has a declaration of a type to which one of the predefined
 120    --  operators apply. The existence of this routine is an artifact of
 121    --  our implementation: a more straightforward but more space-consuming
 122    --  choice would be to make all inherited operators explicit in the
 123    --  symbol table.
 124
 125    procedure Initialize;
 126    --  Initializes data structures used for visibility analysis. Must be
 127    --  called before analyzing each new main source program.
 128
 129    procedure Install_Use_Clauses (Clause : Node_Id);
 130    --  applies the use clauses appearing in a given declarative part,
 131    --  when the corresponding scope has been placed back on the scope
 132    --  stack after unstacking to compile a different context (subunit or
 133    --  parent of generic body).
 134
 135    function In_Open_Scopes (S : Entity_Id) return Boolean;
 136    --  S is the entity of a scope. This function determines if this scope
 137    --  is currently open (i.e. it appears somewhere in the scope stack).
 138
 139    function Is_Appropriate_For_Record (T : Entity_Id) return Boolean;
 140    --  Prefix is appropriate for record if it is of a record type, or
 141    --  an access to such.
 142
 143    function Is_Appropriate_For_Entry_Prefix (T : Entity_Id) return Boolean;
 144    --  True if it is of a task type, a protected type, or else an access
 145    --  to one of these types.
 146
 147    procedure New_Scope (S : Entity_Id);
 148    --  Make new scope stack entry, pushing S, the entity for a scope
 149    --  onto the top of the scope table. The current setting of the scope
 150    --  suppress flags is saved for restoration on exit.
 151
 152    procedure Pop_Scope;
 153    --  Remove top entry from scope stack, restoring the saved setting
 154    --  of the scope suppress flags.
 155
 156    function Present_System_Aux (N : Node_Id := Empty) return Boolean;
 157    --  Return True if the auxiliary system file has been successfully loaded.
 158    --  Otherwise attempt to load it, using the name supplied by a previous
 159    --  Extend_System pragma, and report on the success of the load.
 160    --  If N is present, it is a selected component whose prefix is System,
 161    --  or else a with-clause on system. N is absent when the function is
 162    --  called to find the visibility of implicit operators.
 163
 164    procedure Restore_Scope_Stack;
 165    procedure Save_Scope_Stack;
 166    --  These two procedures are called from Semantics, when a unit U1 is
 167    --  to be compiled in the course of the compilation of another unit U2.
 168    --  This happens whenever Rtsfind is called. U1, the unit retrieved by
 169    --  Rtsfind, must be compiled in its own context, and the current scope
 170    --  stack containing U2 and local scopes must be made unreachable. On
 171    --  return, the contents of the scope stack must be made accessible again.
 172
 173    procedure Use_One_Package (P : Entity_Id; N : Node_Id);
 174    --  Make visible entities declarated in package P potentially use-visible
 175    --  in the current context. Also used in the analysis of subunits, when
 176    --  re-installing use clauses of parent units. N is the use_clause that
 177    --  names P (and possibly other packages).
 178
 179    procedure Use_One_Type (Id : Node_Id);
 180    --  Id is the subtype mark from a use type clause. This procedure makes
 181    --  the primitive operators of the type potentially use-visible.
 182
 183    procedure Set_Use (L : List_Id);
 184    --  Find use clauses that are declarative items in a package declaration
 185    --  and  set the potentially use-visible flags of imported entities before
 186    --  analyzing the corresponding package body.
 187
 188 end Sem_Ch8;