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   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                               T B U I L D                                --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                            $Revision: 1.69 $
  10 --                                                                          --
  11 --          Copyright (C) 1992-2000, Free Software Foundation, Inc.         --
  12 --                                                                          --
  13 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  16 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  17 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  18 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  21 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- GNAT was originally developed  by the GNAT team at  New York University. --
  25 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  26 --                                                                          --
  27 ------------------------------------------------------------------------------
  28
  29 --  This package contains various utility procedures to assist in
  30 --  building specific types of tree nodes.
  31
  32 with Types; use Types;
  33
  34 package Tbuild is
  35
  36    function Make_DT_Component
  37      (Loc  : Source_Ptr;
  38       Typ  : Entity_Id;
  39       I    : Positive)
  40       return Node_Id;
  41    --  Gives a reference to the Ith component of the Dispatch Table of
  42    --  a given Tagged Type.
  43    --
  44    --  I = 1    --> Inheritance_Depth
  45    --  I = 2    --> Tags (array of ancestors)
  46    --  I = 3, 4 --> predefined primitive
  47    --            function _Size (X : Typ) return Long_Long_Integer;
  48    --            function _Equality (X : Typ; Y : Typ'Class) return Boolean;
  49    --  I >= 5   --> User-Defined Primitive Operations
  50
  51    function Make_DT_Access
  52      (Loc : Source_Ptr; Rec : Node_Id; Typ : Entity_Id) return Node_Id;
  53    --  Create an access to the Dispatch Table by using the Tag field
  54    --  of a tagged record : Acc_Dt (Rec.tag).all
  55
  56    function Make_Implicit_If_Statement
  57      (Node            : Node_Id;
  58       Condition       : Node_Id;
  59       Then_Statements : List_Id;
  60       Elsif_Parts     : List_Id := No_List;
  61       Else_Statements : List_Id := No_List)
  62       return            Node_Id;
  63    pragma Inline (Make_Implicit_If_Statement);
  64    --  This function makes an N_If_Statement node whose fields are filled
  65    --  in with the indicated values (see Sinfo), and whose Sloc field is
  66    --  is set to Sloc (Node). The effect is identical to calling function
  67    --  Nmake.Make_If_Statement except that there is a check for restriction
  68    --  No_Implicit_Conditionals, and if this restriction is being violated,
  69    --  an error message is posted on Node.
  70
  71    function Make_Implicit_Label_Declaration
  72      (Loc                 : Source_Ptr;
  73       Defining_Identifier : Node_Id;
  74       Label_Construct     : Node_Id)
  75       return                Node_Id;
  76    --  Used to contruct an implicit label declaration node, including setting
  77    --  the proper Label_Construct field (since Label_Construct is a semantic
  78    --  field, the normal call to Make_Implicit_Label_Declaration does not
  79    --  set this field).
  80
  81    function Make_Implicit_Loop_Statement
  82      (Node                   : Node_Id;
  83       Statements             : List_Id;
  84       Identifier             : Node_Id := Empty;
  85       Iteration_Scheme       : Node_Id := Empty;
  86       Has_Created_Identifier : Boolean := False;
  87       End_Label              : Node_Id := Empty)
  88       return                   Node_Id;
  89    --  This function makes an N_Loop_Statement node whose fields are filled
  90    --  in with the indicated values (see Sinfo), and whose Sloc field is
  91    --  is set to Sloc (Node). The effect is identical to calling function
  92    --  Nmake.Make_Loop_Statement except that there is a check for restrictions
  93    --  No_Implicit_Loops and No_Implicit_Conditionals (the first applying in
  94    --  all cases, and the second only for while loops), and if one of these
  95    --  restrictions is being violated, an error message is posted on Node.
  96
  97    function Make_Integer_Literal
  98      (Loc    : Source_Ptr;
  99       Intval : Int)
 100       return   Node_Id;
 101    pragma Inline (Make_Integer_Literal);
 102    --  A convenient form of Make_Integer_Literal taking Int instead of Uint
 103
 104    function Make_Unsuppress_Block
 105      (Loc   : Source_Ptr;
 106       Check : Name_Id;
 107       Stmts : List_Id)
 108       return  Node_Id;
 109    --  Build a block with a pragma Suppress on 'Check'. Stmts is the
 110    --  statements list that needs protection against the check
 111
 112    function New_Constraint_Error (Loc : Source_Ptr) return Node_Id;
 113    --  This function builds a tree corresponding to the Ada statement
 114    --  "raise Constraint_Error" and returns the root of this tree,
 115    --  the N_Raise_Statement node.
 116
 117    function New_External_Name
 118      (Related_Id   : Name_Id;
 119       Suffix       : Character := ' ';
 120       Suffix_Index : Int       := 0;
 121       Prefix       : Character := ' ')
 122       return         Name_Id;
 123    function New_External_Name
 124      (Related_Id   : Name_Id;
 125       Suffix       : String;
 126       Suffix_Index : Int       := 0;
 127       Prefix       : Character := ' ')
 128       return         Name_Id;
 129    --  Builds a new entry in the names table of the form:
 130    --
 131    --    [Prefix  &] Related_Id [& Suffix] [& Suffix_Index]
 132    --
 133    --  Prefix is prepended only if Prefix is non-blank (in which case it
 134    --  must be an upper case letter other than O,Q,U,W (which are used for
 135    --  identifier encoding, see Namet), and T is reserved for use by implicit
 136    --  types. and X is reserved for use by debug type encoding (see package
 137    --  Exp_Dbug). Note: the reason that Prefix is last is that it is almost
 138    --  always omitted. The notable case of Prefix being non-null is when
 139    --  it is 'T' for an implicit type.
 140
 141    --  Suffix_Index'Image is appended only if the value of Suffix_Index is
 142    --  positive, or if Suffix_Index is negative 1, then a unique serialized
 143    --  suffix is added. If Suffix_Index is zero, then no index is appended.
 144
 145    --  Suffix is also a single upper case letter other than O,Q,U,W,X and is a
 146    --  required parameter (T is permitted). The constructed name is stored
 147    --  using Find_Name so that it can be located using a subsequent Find_Name
 148    --  operation (i.e. it is properly hashed into the names table). The upper
 149    --  case letter given as the Suffix argument ensures that the name does
 150    --  not clash with any Ada identifier name. These generated names are
 151    --  permitted, but not required, to be made public by setting the flag
 152    --  Is_Public in the associated entity.
 153
 154    function New_External_Name
 155      (Suffix       : Character;
 156       Suffix_Index : Nat)
 157       return         Name_Id;
 158    --  Builds a new entry in the names table of the form
 159    --    Suffix & Suffix_Index'Image
 160    --  where Suffix is a single upper case letter other than O,Q,U,W,X and is
 161    --  a required parameter (T is permitted). The constructed name is stored
 162    --  using Find_Name so that it can be located using a subsequent Find_Name
 163    --  operation (i.e. it is properly hashed into the names table). The upper
 164    --  case letter given as the Suffix argument ensures that the name does
 165    --  not clash with any Ada identifier name. These generated names are
 166    --  permitted, but not required, to be made public by setting the flag
 167    --  Is_Public in the associated entity.
 168
 169    function New_Internal_Name (Id_Char : Character) return Name_Id;
 170    --  Id_Char is an upper case letter other than O,Q,U,W (which are reserved
 171    --  for identifier encoding (see Namet package for details) and X which is
 172    --  used for debug encoding (see Exp_Dbug). The letter T is permitted, but
 173    --  is reserved by convention for the case of internally generated types.
 174    --  The result of the call is a new generated unique name of the form XyyyU
 175    --  where X is Id_Char, yyy is a unique serial number, and U is either a
 176    --  lower case s or b indicating if the current unit is a spec or a body.
 177    --
 178    --  The name is entered into the names table using Name_Enter rather than
 179    --  Name_Find, because there can never be a need to locate the entry using
 180    --  the Name_Find procedure later on. Names created by New_Internal_Name
 181    --  are guaranteed to be consistent from one compilation to another (i.e.
 182    --  if the identical unit is compiled with a semantically consistent set
 183    --  of sources, the numbers will be consistent. This means that it is fine
 184    --  to use these as public symbols.
 185
 186    function New_Suffixed_Name
 187      (Related_Id : Name_Id;
 188       Suffix     : String)
 189       return       Name_Id;
 190    --  This function is used to create special suffixed names used by the
 191    --  debugger. Suffix is a string of upper case letters, used to construct
 192    --  the required name. For instance, the special type used to record the
 193    --  fixed-point small is called typ_SMALL where typ is the name of the
 194    --  fixed-point type (as passed in Related_Id), and Suffix is "SMALL".
 195
 196    function New_Occurrence_Of
 197      (Def_Id : Entity_Id;
 198       Loc    : Source_Ptr)
 199       return   Node_Id;
 200    --  New_Occurrence_Of creates an N_Identifier node which is an
 201    --  occurrence of the defining identifier which is passed as its
 202    --  argument. The Entity and Etype of the result are set from
 203    --  the given defining identifier as follows: Entity is simply
 204    --  a copy of Def_Id. Etype is a copy of Def_Id for types, and
 205    --  a copy of the Etype of Def_Id for other entities.
 206
 207    function New_Reference_To
 208      (Def_Id : Entity_Id;
 209       Loc    : Source_Ptr)
 210       return   Node_Id;
 211    --  This is like New_Occurrence_Of, but it does not set the Etype field.
 212    --  It is used from the expander, where Etype fields are generally not set,
 213    --  since they are set when the expanded tree is reanalyzed.
 214
 215    function Checks_Off (N : Node_Id) return Node_Id;
 216    pragma Inline (Checks_Off);
 217    --  Returns an N_Unchecked_Expression node whose expression is the given
 218    --  argument. The results is a subexpression identical to the argument,
 219    --  except that it will be analyzed and resolved with checks off.
 220
 221    function Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
 222    --  Returns an expression that represents the result of a checked convert
 223    --  of expression Exp to type T. If the base type of Exp is T, then no
 224    --  conversion is required, and Exp is returned unchanged. Otherwise an
 225    --  N_Type_Conversion node is constructed to convert the expression.
 226    --  If an N_Type_Conversion node is required, Relocate_Node is used on
 227    --  Exp. This means that it is safe to replace a node by a Convert_To
 228    --  of itself to some other type.
 229
 230    function OK_Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
 231    --  Like Convert_To, except that a conversion node is always generated,
 232    --  and the Conversion_OK flag is set on this conversion node.
 233
 234    function Unchecked_Convert_To
 235      (Typ  : Entity_Id;
 236       Expr : Node_Id)
 237       return Node_Id;
 238    --  Like Convert_To, but if a conversion is actually needed, constructs
 239    --  an N_Unchecked_Type_Conversion node to do the required conversion.
 240
 241 end Tbuild;