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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 --          Copyright (C) 1992-2002, 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 2,  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 COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- GNAT was originally developed  by the GNAT team at  New York University. --
  23 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  24 --                                                                          --
  25 ------------------------------------------------------------------------------
  26
  27 --  This package contains various utility procedures to assist in
  28 --  building specific types of tree nodes.
  29
  30 with Types; use Types;
  31
  32 package Tbuild is
  33
  34    function Checks_Off (N : Node_Id) return Node_Id;
  35    pragma Inline (Checks_Off);
  36    --  Returns an N_Unchecked_Expression node whose expression is the given
  37    --  argument. The results is a subexpression identical to the argument,
  38    --  except that it will be analyzed and resolved with checks off.
  39
  40    function Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
  41    --  Returns an expression that represents the result of a checked convert
  42    --  of expression Exp to type T. If the base type of Exp is T, then no
  43    --  conversion is required, and Exp is returned unchanged. Otherwise an
  44    --  N_Type_Conversion node is constructed to convert the expression.
  45    --  If an N_Type_Conversion node is required, Relocate_Node is used on
  46    --  Exp. This means that it is safe to replace a node by a Convert_To
  47    --  of itself to some other type.
  48
  49    function Make_Byte_Aligned_Attribute_Reference
  50      (Sloc           : Source_Ptr;
  51       Prefix         : Node_Id;
  52       Attribute_Name : Name_Id)
  53       return           Node_Id;
  54    pragma Inline (Make_Byte_Aligned_Attribute_Reference);
  55    --  Like the standard Make_Attribute_Reference but the special flag
  56    --  Must_Be_Byte_Aligned is set in the attribute reference node. The
  57    --  Attribute_Name must be Name_Address or Name_Unrestricted_Access.
  58
  59    function Make_DT_Component
  60      (Loc  : Source_Ptr;
  61       Typ  : Entity_Id;
  62       I    : Positive)
  63       return Node_Id;
  64    --  Gives a reference to the Ith component of the Dispatch Table of
  65    --  a given Tagged Type.
  66    --
  67    --  I = 1    --> Inheritance_Depth
  68    --  I = 2    --> Tags (array of ancestors)
  69    --  I = 3, 4 --> predefined primitive
  70    --            function _Size (X : Typ) return Long_Long_Integer;
  71    --            function _Equality (X : Typ; Y : Typ'Class) return Boolean;
  72    --  I >= 5   --> User-Defined Primitive Operations
  73
  74    function Make_DT_Access
  75      (Loc : Source_Ptr; Rec : Node_Id; Typ : Entity_Id) return Node_Id;
  76    --  Create an access to the Dispatch Table by using the Tag field
  77    --  of a tagged record : Acc_Dt (Rec.tag).all
  78
  79    function Make_Implicit_If_Statement
  80      (Node            : Node_Id;
  81       Condition       : Node_Id;
  82       Then_Statements : List_Id;
  83       Elsif_Parts     : List_Id := No_List;
  84       Else_Statements : List_Id := No_List)
  85       return            Node_Id;
  86    pragma Inline (Make_Implicit_If_Statement);
  87    --  This function makes an N_If_Statement node whose fields are filled
  88    --  in with the indicated values (see Sinfo), and whose Sloc field is
  89    --  is set to Sloc (Node). The effect is identical to calling function
  90    --  Nmake.Make_If_Statement except that there is a check for restriction
  91    --  No_Implicit_Conditionals, and if this restriction is being violated,
  92    --  an error message is posted on Node.
  93
  94    function Make_Implicit_Label_Declaration
  95      (Loc                 : Source_Ptr;
  96       Defining_Identifier : Node_Id;
  97       Label_Construct     : Node_Id)
  98       return                Node_Id;
  99    --  Used to construct an implicit label declaration node, including setting
 100    --  the proper Label_Construct field (since Label_Construct is a semantic
 101    --  field, the normal call to Make_Implicit_Label_Declaration does not
 102    --  set this field).
 103
 104    function Make_Implicit_Loop_Statement
 105      (Node                   : Node_Id;
 106       Statements             : List_Id;
 107       Identifier             : Node_Id := Empty;
 108       Iteration_Scheme       : Node_Id := Empty;
 109       Has_Created_Identifier : Boolean := False;
 110       End_Label              : Node_Id := Empty)
 111       return                   Node_Id;
 112    --  This function makes an N_Loop_Statement node whose fields are filled
 113    --  in with the indicated values (see Sinfo), and whose Sloc field is
 114    --  is set to Sloc (Node). The effect is identical to calling function
 115    --  Nmake.Make_Loop_Statement except that there is a check for restrictions
 116    --  No_Implicit_Loops and No_Implicit_Conditionals (the first applying in
 117    --  all cases, and the second only for while loops), and if one of these
 118    --  restrictions is being violated, an error message is posted on Node.
 119
 120    function Make_Integer_Literal
 121      (Loc    : Source_Ptr;
 122       Intval : Int)
 123       return   Node_Id;
 124    pragma Inline (Make_Integer_Literal);
 125    --  A convenient form of Make_Integer_Literal taking Int instead of Uint
 126
 127    function Make_Raise_Constraint_Error
 128      (Sloc      : Source_Ptr;
 129       Condition : Node_Id := Empty;
 130       Reason    : RT_Exception_Code)
 131       return      Node_Id;
 132    pragma Inline (Make_Raise_Constraint_Error);
 133    --  A convenient form of Make_Raise_Constraint_Error where the Reason
 134    --  is given simply as an enumeration value, rather than a Uint code.
 135
 136    function Make_Raise_Program_Error
 137      (Sloc      : Source_Ptr;
 138       Condition : Node_Id := Empty;
 139       Reason    : RT_Exception_Code)
 140       return      Node_Id;
 141    pragma Inline (Make_Raise_Program_Error);
 142    --  A convenient form of Make_Raise_Program_Error where the Reason
 143    --  is given simply as an enumeration value, rather than a Uint code.
 144
 145    function Make_Raise_Storage_Error
 146      (Sloc      : Source_Ptr;
 147       Condition : Node_Id := Empty;
 148       Reason    : RT_Exception_Code)
 149       return      Node_Id;
 150    pragma Inline (Make_Raise_Storage_Error);
 151    --  A convenient form of Make_Raise_Storage_Error where the Reason
 152    --  is given simply as an enumeration value, rather than a Uint code.
 153
 154    function Make_Unsuppress_Block
 155      (Loc   : Source_Ptr;
 156       Check : Name_Id;
 157       Stmts : List_Id)
 158       return  Node_Id;
 159    --  Build a block with a pragma Suppress on 'Check'. Stmts is the
 160    --  statements list that needs protection against the check
 161
 162    function New_Constraint_Error (Loc : Source_Ptr) return Node_Id;
 163    --  This function builds a tree corresponding to the Ada statement
 164    --  "raise Constraint_Error" and returns the root of this tree,
 165    --  the N_Raise_Statement node.
 166
 167    function New_External_Name
 168      (Related_Id   : Name_Id;
 169       Suffix       : Character := ' ';
 170       Suffix_Index : Int       := 0;
 171       Prefix       : Character := ' ')
 172       return         Name_Id;
 173    function New_External_Name
 174      (Related_Id   : Name_Id;
 175       Suffix       : String;
 176       Suffix_Index : Int       := 0;
 177       Prefix       : Character := ' ')
 178       return         Name_Id;
 179    --  Builds a new entry in the names table of the form:
 180    --
 181    --    [Prefix  &] Related_Id [& Suffix] [& Suffix_Index]
 182    --
 183    --  Prefix is prepended only if Prefix is non-blank (in which case it
 184    --  must be an upper case letter other than O,Q,U,W (which are used for
 185    --  identifier encoding, see Namet), and T is reserved for use by implicit
 186    --  types. and X is reserved for use by debug type encoding (see package
 187    --  Exp_Dbug). Note: the reason that Prefix is last is that it is almost
 188    --  always omitted. The notable case of Prefix being non-null is when
 189    --  it is 'T' for an implicit type.
 190
 191    --  Suffix_Index'Image is appended only if the value of Suffix_Index is
 192    --  positive, or if Suffix_Index is negative 1, then a unique serialized
 193    --  suffix is added. If Suffix_Index is zero, then no index is appended.
 194
 195    --  Suffix is also a single upper case letter other than O,Q,U,W,X and is a
 196    --  required parameter (T is permitted). The constructed name is stored
 197    --  using Find_Name so that it can be located using a subsequent Find_Name
 198    --  operation (i.e. it is properly hashed into the names table). The upper
 199    --  case letter given as the Suffix argument ensures that the name does
 200    --  not clash with any Ada identifier name. These generated names are
 201    --  permitted, but not required, to be made public by setting the flag
 202    --  Is_Public in the associated entity.
 203
 204    function New_External_Name
 205      (Suffix       : Character;
 206       Suffix_Index : Nat)
 207       return         Name_Id;
 208    --  Builds a new entry in the names table of the form
 209    --    Suffix & Suffix_Index'Image
 210    --  where Suffix is a single upper case letter other than O,Q,U,W,X and is
 211    --  a required parameter (T is permitted). The constructed name is stored
 212    --  using Find_Name so that it can be located using a subsequent Find_Name
 213    --  operation (i.e. it is properly hashed into the names table). The upper
 214    --  case letter given as the Suffix argument ensures that the name does
 215    --  not clash with any Ada identifier name. These generated names are
 216    --  permitted, but not required, to be made public by setting the flag
 217    --  Is_Public in the associated entity.
 218
 219    function New_Internal_Name (Id_Char : Character) return Name_Id;
 220    --  Id_Char is an upper case letter other than O,Q,U,W (which are reserved
 221    --  for identifier encoding (see Namet package for details) and X which is
 222    --  used for debug encoding (see Exp_Dbug). The letter T is permitted, but
 223    --  is reserved by convention for the case of internally generated types.
 224    --  The result of the call is a new generated unique name of the form XyyyU
 225    --  where X is Id_Char, yyy is a unique serial number, and U is either a
 226    --  lower case s or b indicating if the current unit is a spec or a body.
 227    --
 228    --  The name is entered into the names table using Name_Enter rather than
 229    --  Name_Find, because there can never be a need to locate the entry using
 230    --  the Name_Find procedure later on. Names created by New_Internal_Name
 231    --  are guaranteed to be consistent from one compilation to another (i.e.
 232    --  if the identical unit is compiled with a semantically consistent set
 233    --  of sources, the numbers will be consistent. This means that it is fine
 234    --  to use these as public symbols.
 235
 236    function New_Occurrence_Of
 237      (Def_Id : Entity_Id;
 238       Loc    : Source_Ptr)
 239       return   Node_Id;
 240    --  New_Occurrence_Of creates an N_Identifier node which is an
 241    --  occurrence of the defining identifier which is passed as its
 242    --  argument. The Entity and Etype of the result are set from
 243    --  the given defining identifier as follows: Entity is simply
 244    --  a copy of Def_Id. Etype is a copy of Def_Id for types, and
 245    --  a copy of the Etype of Def_Id for other entities.
 246
 247    function New_Reference_To
 248      (Def_Id : Entity_Id;
 249       Loc    : Source_Ptr)
 250       return   Node_Id;
 251    --  This is like New_Occurrence_Of, but it does not set the Etype field.
 252    --  It is used from the expander, where Etype fields are generally not set,
 253    --  since they are set when the expanded tree is reanalyzed.
 254
 255    function New_Suffixed_Name
 256      (Related_Id : Name_Id;
 257       Suffix     : String)
 258       return       Name_Id;
 259    --  This function is used to create special suffixed names used by the
 260    --  debugger. Suffix is a string of upper case letters, used to construct
 261    --  the required name. For instance, the special type used to record the
 262    --  fixed-point small is called typ_SMALL where typ is the name of the
 263    --  fixed-point type (as passed in Related_Id), and Suffix is "SMALL".
 264
 265    function OK_Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
 266    --  Like Convert_To, except that a conversion node is always generated,
 267    --  and the Conversion_OK flag is set on this conversion node.
 268
 269    function Unchecked_Convert_To
 270      (Typ  : Entity_Id;
 271       Expr : Node_Id)
 272       return Node_Id;
 273    --  Like Convert_To, but if a conversion is actually needed, constructs
 274    --  an N_Unchecked_Type_Conversion node to do the required conversion.
 275
 276 end Tbuild;