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) 2006-2010, 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    procedure Build_CW_Membership
  45      (Loc          : Source_Ptr;
  46       Obj_Tag_Node : in out Node_Id;
  47       Typ_Tag_Node : Node_Id;
  48       Related_Nod  : Node_Id;
  49       New_Node     : out Node_Id);
  50    --  Build code that returns true if Obj_Tag is in Typ_Tag'Class. Each DT
  51    --  has a table of ancestors and its inheritance level (Idepth). Obj is in
  52    --  Typ'Class if Typ'Tag is found in the table of ancestors referenced by
  53    --  Obj'Tag. Knowing the level of inheritance of both types, this can be
  54    --  computed in constant time by the formula:
  55    --
  56    --   Index := TSD (Obj'Tag).Idepth - TSD (Typ'Tag).Idepth;
  57    --   Index > 0 and then TSD (Obj'Tag).Tags_Table (Index) = Typ'Tag
  58    --
  59    --  Related_Nod is the node where the implicit declaration of variable Index
  60    --  is inserted. Obj_Tag_Node is relocated.
  61
  62    function Build_Get_Access_Level
  63      (Loc      : Source_Ptr;
  64       Tag_Node : Node_Id) return Node_Id;
  65    --  Build code that retrieves the accessibility level of the tagged type.
  66    --
  67    --  Generates: TSD (Tag).Access_Level
  68
  69    procedure Build_Get_Predefined_Prim_Op_Address
  70      (Loc      : Source_Ptr;
  71       Position : Uint;
  72       Tag_Node : in out Node_Id;
  73       New_Node : out Node_Id);
  74    --  Given a pointer to a dispatch table (T) and a position in the DT, build
  75    --  code that gets the address of the predefined virtual function stored in
  76    --  it (used for dispatching calls). Tag_Node is relocated.
  77    --
  78    --  Generates: Predefined_DT (Tag).D (Position);
  79
  80    procedure Build_Get_Prim_Op_Address
  81      (Loc      : Source_Ptr;
  82       Typ      : Entity_Id;
  83       Position : Uint;
  84       Tag_Node : in out Node_Id;
  85       New_Node : out Node_Id);
  86    --  Build code that retrieves the address of the virtual function stored in
  87    --  a given position of the dispatch table (used for dispatching calls).
  88    --  Tag_Node is relocated.
  89    --
  90    --  Generates: To_Tag (Tag).D (Position);
  91
  92    function Build_Get_Transportable
  93      (Loc      : Source_Ptr;
  94       Tag_Node : Node_Id) return Node_Id;
  95    --  Build code that retrieves the value of the Transportable flag for
  96    --  the given Tag.
  97    --
  98    --  Generates: TSD (Tag).Transportable;
  99
 100    function Build_Inherit_CPP_Prims (Typ : Entity_Id) return List_Id;
 101    --  Build code that copies from Typ's parent the dispatch table slots of
 102    --  inherited primitives and updates slots of overridden primitives. The
 103    --  generated code handles primary and secondary dispatch tables of Typ.
 104
 105    function Build_Inherit_Predefined_Prims
 106      (Loc          : Source_Ptr;
 107       Old_Tag_Node : Node_Id;
 108       New_Tag_Node : Node_Id) return Node_Id;
 109    --  Build code that inherits the predefined primitives of the parent.
 110    --
 111    --  Generates: Predefined_DT (New_T).D (All_Predefined_Prims) :=
 112    --               Predefined_DT (Old_T).D (All_Predefined_Prims);
 113    --
 114    --  Required to build non-library level dispatch tables. Also required
 115    --  when compiling without static dispatch tables support.
 116
 117    function Build_Inherit_Prims
 118      (Loc          : Source_Ptr;
 119       Typ          : Entity_Id;
 120       Old_Tag_Node : Node_Id;
 121       New_Tag_Node : Node_Id;
 122       Num_Prims    : Nat) return Node_Id;
 123    --  Build code that inherits Num_Prims user-defined primitives from the
 124    --  dispatch table of the parent type of tagged type Typ. It is used to
 125    --  copy the dispatch table of the parent in the following cases:
 126    --    a) case of derivations of CPP_Class types
 127    --    b) tagged types whose dispatch table is not statically allocated
 128    --
 129    --  Generates:
 130    --    New_Tag.Prims_Ptr (1 .. Num_Prims) :=
 131    --      Old_Tag.Prims_Ptr (1 .. Num_Prims);
 132
 133    function Build_Offset_To_Top
 134      (Loc       : Source_Ptr;
 135       This_Node : Node_Id) return Node_Id;
 136    --  Build code that references the Offset_To_Top component of the primary
 137    --  or secondary dispatch table associated with This_Node. This subprogram
 138    --  provides a subset of the functionality provided by the function
 139    --  Offset_To_Top of package Ada.Tags, and is only called by the frontend
 140    --  when such routine is not available in a configurable runtime.
 141    --
 142    --  Generates:
 143    --    Offset_To_Top_Ptr
 144    --      (Address!(Tag_Ptr!(This).all) - Offset_To_Top_Offset)
 145
 146    function Build_Set_Predefined_Prim_Op_Address
 147      (Loc          : Source_Ptr;
 148       Tag_Node     : Node_Id;
 149       Position     : Uint;
 150       Address_Node : Node_Id) return Node_Id;
 151    --  Build code that saves the address of a virtual function in a given
 152    --  Position of the portion of the dispatch table associated with the
 153    --  predefined primitives of Tag. Called from Exp_Disp.Fill_DT_Entry
 154    --  and Exp_Disp.Fill_Secondary_DT_Entry. It is used for:
 155    --   1) Filling the dispatch table of CPP_Class types.
 156    --   2) Late overriding (see Check_Dispatching_Operation).
 157    --
 158    --  Generates: Predefined_DT (Tag).D (Position) := Value
 159
 160    function Build_Set_Prim_Op_Address
 161      (Loc          : Source_Ptr;
 162       Typ          : Entity_Id;
 163       Tag_Node     : Node_Id;
 164       Position     : Uint;
 165       Address_Node : Node_Id) return Node_Id;
 166    --  Build code that saves the address of a virtual function in a given
 167    --  Position of the dispatch table associated with the Tag. Called from
 168    --  Exp_Disp.Fill_DT_Entry and Exp_Disp.Fill_Secondary_DT_Entry. Used for:
 169    --   1) Filling the dispatch table of CPP_Class types.
 170    --   2) Late overriding (see Check_Dispatching_Operation).
 171    --
 172    --  Generates: Tag.D (Position) := Value
 173
 174    function Build_Set_Size_Function
 175      (Loc       : Source_Ptr;
 176       Tag_Node  : Node_Id;
 177       Size_Func : Entity_Id) return Node_Id;
 178    --  Build code that saves in the TSD the address of the function
 179    --  calculating _size of the object.
 180
 181    function Build_Set_Static_Offset_To_Top
 182      (Loc          : Source_Ptr;
 183       Iface_Tag    : Node_Id;
 184       Offset_Value : Node_Id) return Node_Id;
 185    --  Build code that initialize the Offset_To_Top component of the
 186    --  secondary dispatch table referenced by Iface_Tag.
 187    --
 188    --  Generates:
 189    --    Offset_To_Top_Ptr
 190    --      (Address!(Tag_Ptr!(This).all) - Offset_To_Top_Offset).all
 191    --     := Offset_Value
 192
 193 end Exp_Atag;