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) 2006-2023, 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      (Typ   : Entity_Id;
  39       Stmts : List_Id);
  40    --  Ada 2005 (AI-345): Build statements that are common to the expansion of
  41    --  timed, asynchronous, and conditional select and append them to Stmts.
  42    --  Typ is the tagged type used for dispatching calls.
  43
  44    function Build_Get_Access_Level
  45      (Loc      : Source_Ptr;
  46       Tag_Node : Node_Id) return Node_Id;
  47    --  Build code that retrieves the accessibility level of the tagged type.
  48    --
  49    --  Generates: TSD (Tag).Access_Level
  50
  51    function Build_Get_Alignment
  52      (Loc      : Source_Ptr;
  53       Tag_Node : Node_Id) return Node_Id;
  54    --  Build code that retrieves the alignment of the tagged type.
  55    --  Generates: TSD (Tag).Alignment
  56
  57    procedure Build_Get_Predefined_Prim_Op_Address
  58      (Loc      : Source_Ptr;
  59       Position : Uint;
  60       Tag_Node : in out Node_Id;
  61       New_Node : out Node_Id);
  62    --  Given a pointer to a dispatch table (T) and a position in the DT, build
  63    --  code that gets the address of the predefined virtual function stored in
  64    --  it (used for dispatching calls). Tag_Node is relocated.
  65    --
  66    --  Generates: Predefined_DT (Tag).D (Position);
  67
  68    procedure Build_Get_Prim_Op_Address
  69      (Loc      : Source_Ptr;
  70       Typ      : Entity_Id;
  71       Position : Uint;
  72       Tag_Node : in out Node_Id;
  73       New_Node : out Node_Id);
  74    --  Build code that retrieves the address of the virtual function stored in
  75    --  a given position of the dispatch table (used for dispatching calls).
  76    --  Tag_Node is relocated.
  77    --
  78    --  Generates: To_Tag (Tag).D (Position);
  79
  80    function Build_Get_Transportable
  81      (Loc      : Source_Ptr;
  82       Tag_Node : Node_Id) return Node_Id;
  83    --  Build code that retrieves the value of the Transportable flag for
  84    --  the given Tag.
  85    --
  86    --  Generates: TSD (Tag).Transportable;
  87
  88    function Build_Inherit_CPP_Prims (Typ : Entity_Id) return List_Id;
  89    --  Build code that copies from Typ's parent the dispatch table slots of
  90    --  inherited primitives and updates slots of overridden primitives. The
  91    --  generated code handles primary and secondary dispatch tables of Typ.
  92
  93    function Build_Inherit_Predefined_Prims
  94      (Loc              : Source_Ptr;
  95       Old_Tag_Node     : Node_Id;
  96       New_Tag_Node     : Node_Id;
  97       Num_Predef_Prims : Nat) return Node_Id;
  98    --  Build code that inherits the predefined primitives of the parent.
  99    --
 100    --  Generates: Predefined_DT (New_T).D (All_Predefined_Prims) :=
 101    --               Predefined_DT (Old_T).D (All_Predefined_Prims);
 102    --
 103    --  Required to build non-library level dispatch tables. Also required
 104    --  when compiling without static dispatch tables support.
 105
 106    function Build_Inherit_Prims
 107      (Loc          : Source_Ptr;
 108       Typ          : Entity_Id;
 109       Old_Tag_Node : Node_Id;
 110       New_Tag_Node : Node_Id;
 111       Num_Prims    : Nat) return Node_Id;
 112    --  Build code that inherits Num_Prims user-defined primitives from the
 113    --  dispatch table of the parent type of tagged type Typ. It is used to
 114    --  copy the dispatch table of the parent in the following cases:
 115    --    a) case of derivations of CPP_Class types
 116    --    b) tagged types whose dispatch table is not statically allocated
 117    --
 118    --  Generates:
 119    --    New_Tag.Prims_Ptr (1 .. Num_Prims) :=
 120    --      Old_Tag.Prims_Ptr (1 .. Num_Prims);
 121
 122    function Build_Offset_To_Top
 123      (Loc       : Source_Ptr;
 124       This_Node : Node_Id) return Node_Id;
 125    --  Build code that references the Offset_To_Top component of the primary
 126    --  or secondary dispatch table associated with This_Node. This subprogram
 127    --  provides a subset of the functionality provided by the function
 128    --  Offset_To_Top of package Ada.Tags, and is only called by the frontend
 129    --  when such routine is not available in a configurable runtime.
 130    --
 131    --  Generates:
 132    --    Offset_To_Top_Ptr
 133    --      (Address!(Tag_Ptr!(This).all) - Offset_To_Top_Offset).all
 134
 135    function Build_Set_Predefined_Prim_Op_Address
 136      (Loc          : Source_Ptr;
 137       Tag_Node     : Node_Id;
 138       Position     : Uint;
 139       Address_Node : Node_Id) return Node_Id;
 140    --  Build code that saves the address of a virtual function in a given
 141    --  Position of the portion of the dispatch table associated with the
 142    --  predefined primitives of Tag. Called from Exp_Disp.Fill_DT_Entry
 143    --  and Exp_Disp.Fill_Secondary_DT_Entry. It is used for:
 144    --   1) Filling the dispatch table of CPP_Class types.
 145    --   2) Late overriding (see Check_Dispatching_Operation).
 146    --
 147    --  Generates: Predefined_DT (Tag).D (Position) := Value
 148
 149    function Build_Set_Prim_Op_Address
 150      (Loc          : Source_Ptr;
 151       Typ          : Entity_Id;
 152       Tag_Node     : Node_Id;
 153       Position     : Uint;
 154       Address_Node : Node_Id) return Node_Id;
 155    --  Build code that saves the address of a virtual function in a given
 156    --  Position of the dispatch table associated with the Tag. Called from
 157    --  Exp_Disp.Fill_DT_Entry and Exp_Disp.Fill_Secondary_DT_Entry. Used for:
 158    --   1) Filling the dispatch table of CPP_Class types.
 159    --   2) Late overriding (see Check_Dispatching_Operation).
 160    --
 161    --  Generates: Tag.D (Position) := Value
 162
 163    function Build_Set_Size_Function
 164      (Loc       : Source_Ptr;
 165       Tag_Node  : Node_Id;
 166       Size_Func : Entity_Id) return Node_Id;
 167    --  Build code that saves in the TSD the address of the function
 168    --  calculating _size of the object.
 169
 170    function Build_Set_Static_Offset_To_Top
 171      (Loc          : Source_Ptr;
 172       Iface_Tag    : Node_Id;
 173       Offset_Value : Node_Id) return Node_Id;
 174    --  Build code that initialize the Offset_To_Top component of the
 175    --  secondary dispatch table referenced by Iface_Tag.
 176    --
 177    --  Generates:
 178    --    Offset_To_Top_Ptr
 179    --      (Address!(Tag_Ptr!(This).all) - Offset_To_Top_Offset).all
 180    --     := Offset_Value
 181
 182 end Exp_Atag;