gcc/ada/exp_atag.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             E X P _ A T A G                              --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2006-2008, 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 ------------------------------------------------------------------------------
  25
  26 --  This package contains routines involved in the frontend expansion of
  27 --  subprograms of package Ada.Tags
  28
  29 with Types; use Types;
  30 with Uintp; use Uintp;
  31
  32 package Exp_Atag is
  33
  34    --  Note: In all the subprograms of this package formal 'Loc' is the source
  35    --  location used in constructing the corresponding nodes.
  36
  37    procedure Build_Common_Dispatching_Select_Statements
  38      (Loc    : Source_Ptr;
  39       DT_Ptr : Entity_Id;
  40       Stmts  : List_Id);
  41    --  Ada 2005 (AI-345): Generate statements that are common between timed,
  42    --  asynchronous, and conditional select expansion.
  43
  44    function Build_CW_Membership
  45      (Loc          : Source_Ptr;
  46       Obj_Tag_Node : Node_Id;
  47       Typ_Tag_Node : Node_Id) return Node_Id;
  48    --  Build code that returns true if Obj_Tag is in Typ_Tag'Class. Each DT
  49    --  has a table of ancestors and its inheritance level (Idepth). Obj is in
  50    --  Typ'Class if Typ'Tag is found in the table of ancestors referenced by
  51    --  Obj'Tag. Knowing the level of inheritance of both types, this can be
  52    --  computed in constant time by the formula:
  53    --
  54    --   TSD (Obj'tag).Tags_Table (TSD (Obj'tag).Idepth - TSD (Typ'tag).Idepth)
  55    --     = Typ'tag
  56
  57    function Build_Get_Access_Level
  58      (Loc      : Source_Ptr;
  59       Tag_Node : Node_Id) return Node_Id;
  60    --  Build code that retrieves the accessibility level of the tagged type.
  61    --
  62    --  Generates: TSD (Tag).Access_Level
  63
  64    function Build_Get_Predefined_Prim_Op_Address
  65      (Loc      : Source_Ptr;
  66       Tag_Node : Node_Id;
  67       Position : Uint) return Node_Id;
  68    --  Given a pointer to a dispatch table (T) and a position in the DT, build
  69    --  code that gets the address of the predefined virtual function stored in
  70    --  it (used for dispatching calls).
  71    --
  72    --  Generates: Predefined_DT (Tag).D (Position);
  73
  74    function Build_Get_Prim_Op_Address
  75      (Loc      : Source_Ptr;
  76       Typ      : Entity_Id;
  77       Tag_Node : Node_Id;
  78       Position : Uint) return Node_Id;
  79    --  Build code that retrieves the address of the virtual function stored in
  80    --  a given position of the dispatch table (used for dispatching calls).
  81    --
  82    --  Generates: To_Tag (Tag).D (Position);
  83
  84    function Build_Get_Transportable
  85      (Loc      : Source_Ptr;
  86       Tag_Node : Node_Id) return Node_Id;
  87    --  Build code that retrieves the value of the Transportable flag for
  88    --  the given Tag.
  89    --
  90    --  Generates: TSD (Tag).Transportable;
  91
  92    function Build_Inherit_Predefined_Prims
  93      (Loc          : Source_Ptr;
  94       Old_Tag_Node : Node_Id;
  95       New_Tag_Node : Node_Id) return Node_Id;
  96    --  Build code that inherits the predefined primitives of the parent.
  97    --
  98    --  Generates: Predefined_DT (New_T).D (All_Predefined_Prims) :=
  99    --               Predefined_DT (Old_T).D (All_Predefined_Prims);
 100    --
 101    --  Required to build non-library level dispatch tables. Also required
 102    --  when compiling without static dispatch tables support.
 103
 104    function Build_Inherit_Prims
 105      (Loc          : Source_Ptr;
 106       Typ          : Entity_Id;
 107       Old_Tag_Node : Node_Id;
 108       New_Tag_Node : Node_Id;
 109       Num_Prims    : Nat) return Node_Id;
 110    --  Build code that inherits Num_Prims user-defined primitives from the
 111    --  dispatch table of the parent type of tagged type Typ. It is used to
 112    --  copy the dispatch table of the parent in the following cases:
 113    --    a) case of derivations of CPP_Class types
 114    --    b) tagged types whose dispatch table is not statically allocated
 115    --
 116    --  Generates:
 117    --    New_Tag.Prims_Ptr (1 .. Num_Prims) :=
 118    --      Old_Tag.Prims_Ptr (1 .. Num_Prims);
 119
 120    function Build_Offset_To_Top
 121      (Loc       : Source_Ptr;
 122       This_Node : Node_Id) return Node_Id;
 123    --  Build code that references the Offset_To_Top component of the primary
 124    --  or secondary dispatch table associated with This_Node. This subprogram
 125    --  provides a subset of the functionality provided by the function
 126    --  Offset_To_Top of package Ada.Tags, and is only called by the frontend
 127    --  when such routine is not available in a configurable runtime.
 128    --
 129    --  Generates:
 130    --    Offset_To_Top_Ptr
 131    --      (Address!(Tag_Ptr!(This).all) - Offset_To_Top_Offset)
 132
 133    function Build_Set_Predefined_Prim_Op_Address
 134      (Loc          : Source_Ptr;
 135       Tag_Node     : Node_Id;
 136       Position     : Uint;
 137       Address_Node : Node_Id) return Node_Id;
 138    --  Build code that saves the address of a virtual function in a given
 139    --  Position of the portion of the dispatch table associated with the
 140    --  predefined primitives of Tag. Called from Exp_Disp.Fill_DT_Entry
 141    --  and Exp_Disp.Fill_Secondary_DT_Entry. It is used for:
 142    --   1) Filling the dispatch table of CPP_Class types.
 143    --   2) Late overriding (see Check_Dispatching_Operation).
 144    --
 145    --  Generates: Predefined_DT (Tag).D (Position) := Value
 146
 147    function Build_Set_Prim_Op_Address
 148      (Loc          : Source_Ptr;
 149       Typ          : Entity_Id;
 150       Tag_Node     : Node_Id;
 151       Position     : Uint;
 152       Address_Node : Node_Id) return Node_Id;
 153    --  Build code that saves the address of a virtual function in a given
 154    --  Position of the dispatch table associated with the Tag. Called from
 155    --  Exp_Disp.Fill_DT_Entry and Exp_Disp.Fill_Secondary_DT_Entry. Used for:
 156    --   1) Filling the dispatch table of CPP_Class types.
 157    --   2) Late overriding (see Check_Dispatching_Operation).
 158    --
 159    --  Generates: Tag.D (Position) := Value
 160
 161    function Build_Set_Size_Function
 162      (Loc       : Source_Ptr;
 163       Tag_Node  : Node_Id;
 164       Size_Func : Entity_Id) return Node_Id;
 165    --  Build code that saves in the TSD the address of the function
 166    --  calculating _size of the object.
 167
 168    function Build_Set_Static_Offset_To_Top
 169      (Loc          : Source_Ptr;
 170       Iface_Tag    : Node_Id;
 171       Offset_Value : Node_Id) return Node_Id;
 172    --  Build code that initialize the Offset_To_Top component of the
 173    --  secondary dispatch table referenced by Iface_Tag.
 174    --
 175    --  Generates:
 176    --    Offset_To_Top_Ptr
 177    --      (Address!(Tag_Ptr!(This).all) - Offset_To_Top_Offset).all
 178    --     := Offset_Value
 179
 180 end Exp_Atag;