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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) 1992-2007, 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 various utility procedures to assist in
  27 --  building specific types of tree nodes.
  28
  29 with Namet; use Namet;
  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    procedure Discard_Node (N : Node_Or_Entity_Id);
  50    pragma Inline (Discard_Node);
  51    --  This is a dummy procedure that simply returns and does nothing.
  52    --  It is used when a function returning a Node_Id value is called
  53    --  for its side effect (e.g. a call to Make to construct a node)
  54    --  but the Node_Id value is not required.
  55
  56    procedure Discard_List (L : List_Id);
  57    pragma Inline (Discard_List);
  58    --  This is a dummy procedure that simply returns and does nothing.
  59    --  It is used when a function returning a Node_Id value is called
  60    --  for its side effect (e.g. a call to the pareser to parse a list
  61    --  of compilation units), but the List_Id value is not required.
  62
  63    function Make_Byte_Aligned_Attribute_Reference
  64      (Sloc           : Source_Ptr;
  65       Prefix         : Node_Id;
  66       Attribute_Name : Name_Id) return Node_Id;
  67    pragma Inline (Make_Byte_Aligned_Attribute_Reference);
  68    --  Like the standard Make_Attribute_Reference but the special flag
  69    --  Must_Be_Byte_Aligned is set in the attribute reference node. The
  70    --  Attribute_Name must be Name_Address or Name_Unrestricted_Access.
  71
  72    function Make_DT_Access
  73      (Loc : Source_Ptr; Rec : Node_Id; Typ : Entity_Id) return Node_Id;
  74    --  Create an access to the Dispatch Table by using the Tag field
  75    --  of a tagged record : Acc_Dt (Rec.tag).all
  76
  77    function Make_Implicit_Exception_Handler
  78      (Sloc              : Source_Ptr;
  79       Choice_Parameter  : Node_Id := Empty;
  80       Exception_Choices : List_Id;
  81       Statements        : List_Id) return Node_Id;
  82    pragma Inline (Make_Implicit_Exception_Handler);
  83    --  This is just like Make_Exception_Handler, except that it also sets the
  84    --  Local_Raise_Statements field to No_Elist, ensuring that it is properly
  85    --  initialized. This should always be used when creating exception handlers
  86    --  as part of the expansion.
  87
  88    function Make_Implicit_If_Statement
  89      (Node            : Node_Id;
  90       Condition       : Node_Id;
  91       Then_Statements : List_Id;
  92       Elsif_Parts     : List_Id := No_List;
  93       Else_Statements : List_Id := No_List) return Node_Id;
  94    pragma Inline (Make_Implicit_If_Statement);
  95    --  This function makes an N_If_Statement node whose fields are filled
  96    --  in with the indicated values (see Sinfo), and whose Sloc field is
  97    --  is set to Sloc (Node). The effect is identical to calling function
  98    --  Nmake.Make_If_Statement except that there is a check for restriction
  99    --  No_Implicit_Conditionals, and if this restriction is being violated,
 100    --  an error message is posted on Node.
 101
 102    function Make_Implicit_Label_Declaration
 103      (Loc                 : Source_Ptr;
 104       Defining_Identifier : Node_Id;
 105       Label_Construct     : Node_Id) return Node_Id;
 106    --  Used to contruct an implicit label declaration node, including setting
 107    --  the proper Label_Construct field (since Label_Construct is a semantic
 108    --  field, the normal call to Make_Implicit_Label_Declaration does not
 109    --  set this field).
 110
 111    function Make_Implicit_Loop_Statement
 112      (Node                   : Node_Id;
 113       Statements             : List_Id;
 114       Identifier             : Node_Id := Empty;
 115       Iteration_Scheme       : Node_Id := Empty;
 116       Has_Created_Identifier : Boolean := False;
 117       End_Label              : Node_Id := Empty) return Node_Id;
 118    --  This function makes an N_Loop_Statement node whose fields are filled
 119    --  in with the indicated values (see Sinfo), and whose Sloc field is
 120    --  is set to Sloc (Node). The effect is identical to calling function
 121    --  Nmake.Make_Loop_Statement except that there is a check for restrictions
 122    --  No_Implicit_Loops and No_Implicit_Conditionals (the first applying in
 123    --  all cases, and the second only for while loops), and if one of these
 124    --  restrictions is being violated, an error message is posted on Node.
 125
 126    function Make_Integer_Literal
 127      (Loc    : Source_Ptr;
 128       Intval : Int) return Node_Id;
 129    pragma Inline (Make_Integer_Literal);
 130    --  A convenient form of Make_Integer_Literal taking Int instead of Uint
 131
 132    function Make_Linker_Section_Pragma
 133      (Ent : Entity_Id;
 134       Loc : Source_Ptr;
 135       Sec : String) return Node_Id;
 136    --  Construct a Linker_Section pragma for entity Ent, using string Sec as
 137    --  the section name. Loc is the Sloc value to use in building the pragma.
 138
 139    function Make_Raise_Constraint_Error
 140      (Sloc      : Source_Ptr;
 141       Condition : Node_Id := Empty;
 142       Reason    : RT_Exception_Code) return Node_Id;
 143    pragma Inline (Make_Raise_Constraint_Error);
 144    --  A convenient form of Make_Raise_Constraint_Error where the Reason
 145    --  is given simply as an enumeration value, rather than a Uint code.
 146
 147    function Make_Raise_Program_Error
 148      (Sloc      : Source_Ptr;
 149       Condition : Node_Id := Empty;
 150       Reason    : RT_Exception_Code) return Node_Id;
 151    pragma Inline (Make_Raise_Program_Error);
 152    --  A convenient form of Make_Raise_Program_Error where the Reason
 153    --  is given simply as an enumeration value, rather than a Uint code.
 154
 155    function Make_Raise_Storage_Error
 156      (Sloc      : Source_Ptr;
 157       Condition : Node_Id := Empty;
 158       Reason    : RT_Exception_Code) return Node_Id;
 159    pragma Inline (Make_Raise_Storage_Error);
 160    --  A convenient form of Make_Raise_Storage_Error where the Reason
 161    --  is given simply as an enumeration value, rather than a Uint code.
 162
 163    function Make_String_Literal
 164      (Sloc   : Source_Ptr;
 165       Strval : String) return Node_Id;
 166    --  A convenient form of Make_String_Literal, where the string value
 167    --  is given as a normal string instead of a String_Id value.
 168
 169    function Make_Unsuppress_Block
 170      (Loc   : Source_Ptr;
 171       Check : Name_Id;
 172       Stmts : List_Id) return Node_Id;
 173    --  Build a block with a pragma Suppress on 'Check'. Stmts is the
 174    --  statements list that needs protection against the check
 175
 176    function New_Constraint_Error (Loc : Source_Ptr) return Node_Id;
 177    --  This function builds a tree corresponding to the Ada statement
 178    --  "raise Constraint_Error" and returns the root of this tree,
 179    --  the N_Raise_Statement node.
 180
 181    function New_External_Name
 182      (Related_Id   : Name_Id;
 183       Suffix       : Character := ' ';
 184       Suffix_Index : Int       := 0;
 185       Prefix       : Character := ' ') return Name_Id;
 186    function New_External_Name
 187      (Related_Id   : Name_Id;
 188       Suffix       : String;
 189       Suffix_Index : Int       := 0;
 190       Prefix       : Character := ' ') return Name_Id;
 191    --  Builds a new entry in the names table of the form:
 192    --
 193    --    [Prefix  &] Related_Id [& Suffix] [& Suffix_Index]
 194    --
 195    --  Prefix is prepended only if Prefix is non-blank (in which case it
 196    --  must be an upper case letter other than O,Q,U,W (which are used for
 197    --  identifier encoding, see Namet), and T is reserved for use by implicit
 198    --  types. and X is reserved for use by debug type encoding (see package
 199    --  Exp_Dbug). Note: the reason that Prefix is last is that it is almost
 200    --  always omitted. The notable case of Prefix being non-null is when
 201    --  it is 'T' for an implicit type.
 202
 203    --  Suffix_Index'Image is appended only if the value of Suffix_Index is
 204    --  positive, or if Suffix_Index is negative 1, then a unique serialized
 205    --  suffix is added. If Suffix_Index is zero, then no index is appended.
 206
 207    --  Suffix is also a single upper case letter other than O,Q,U,W,X and is a
 208    --  required parameter (T is permitted). The constructed name is stored
 209    --  using Find_Name so that it can be located using a subsequent Find_Name
 210    --  operation (i.e. it is properly hashed into the names table). The upper
 211    --  case letter given as the Suffix argument ensures that the name does
 212    --  not clash with any Ada identifier name. These generated names are
 213    --  permitted, but not required, to be made public by setting the flag
 214    --  Is_Public in the associated entity.
 215
 216    function New_External_Name
 217      (Suffix       : Character;
 218       Suffix_Index : Nat) return Name_Id;
 219    --  Builds a new entry in the names table of the form
 220    --    Suffix & Suffix_Index'Image
 221    --  where Suffix is a single upper case letter other than O,Q,U,W,X and is
 222    --  a required parameter (T is permitted). The constructed name is stored
 223    --  using Find_Name so that it can be located using a subsequent Find_Name
 224    --  operation (i.e. it is properly hashed into the names table). The upper
 225    --  case letter given as the Suffix argument ensures that the name does
 226    --  not clash with any Ada identifier name. These generated names are
 227    --  permitted, but not required, to be made public by setting the flag
 228    --  Is_Public in the associated entity.
 229
 230    function New_Internal_Name (Id_Char : Character) return Name_Id;
 231    --  Id_Char is an upper case letter other than O,Q,U,W (which are reserved
 232    --  for identifier encoding (see Namet package for details) and X which is
 233    --  used for debug encoding (see Exp_Dbug). The letter T is permitted, but
 234    --  is reserved by convention for the case of internally generated types.
 235    --  The result of the call is a new generated unique name of the form XyyyU
 236    --  where X is Id_Char, yyy is a unique serial number, and U is either a
 237    --  lower case s or b indicating if the current unit is a spec or a body.
 238    --
 239    --  The name is entered into the names table using Name_Enter rather than
 240    --  Name_Find, because there can never be a need to locate the entry using
 241    --  the Name_Find procedure later on. Names created by New_Internal_Name
 242    --  are guaranteed to be consistent from one compilation to another (i.e.
 243    --  if the identical unit is compiled with a semantically consistent set
 244    --  of sources, the numbers will be consistent. This means that it is fine
 245    --  to use these as public symbols.
 246
 247    function New_Occurrence_Of
 248      (Def_Id : Entity_Id;
 249       Loc    : Source_Ptr) return Node_Id;
 250    --  New_Occurrence_Of creates an N_Identifier node which is an
 251    --  occurrence of the defining identifier which is passed as its
 252    --  argument. The Entity and Etype of the result are set from
 253    --  the given defining identifier as follows: Entity is simply
 254    --  a copy of Def_Id. Etype is a copy of Def_Id for types, and
 255    --  a copy of the Etype of Def_Id for other entities.
 256
 257    function New_Reference_To
 258      (Def_Id : Entity_Id;
 259       Loc    : Source_Ptr) return Node_Id;
 260    --  This is like New_Occurrence_Of, but it does not set the Etype field.
 261    --  It is used from the expander, where Etype fields are generally not set,
 262    --  since they are set when the expanded tree is reanalyzed.
 263
 264    function New_Suffixed_Name
 265      (Related_Id : Name_Id;
 266       Suffix     : String) return Name_Id;
 267    --  This function is used to create special suffixed names used by the
 268    --  debugger. Suffix is a string of upper case letters, used to construct
 269    --  the required name. For instance, the special type used to record the
 270    --  fixed-point small is called typ_SMALL where typ is the name of the
 271    --  fixed-point type (as passed in Related_Id), and Suffix is "SMALL".
 272
 273    function OK_Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
 274    --  Like Convert_To, except that a conversion node is always generated,
 275    --  and the Conversion_OK flag is set on this conversion node.
 276
 277    function Unchecked_Convert_To
 278      (Typ  : Entity_Id;
 279       Expr : Node_Id) return Node_Id;
 280    --  Like Convert_To, but if a conversion is actually needed, constructs
 281    --  an N_Unchecked_Type_Conversion node to do the required conversion.
 282
 283 end Tbuild;