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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                               T B U I L D                                --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 1992-2011, Free Software Foundation, Inc.         --

--                                                                          --

-- GNAT is free software;  you can  redistribute it  and/or modify it under --

-- terms of the  GNU General Public License as published  by the Free Soft- --

-- ware  Foundation;  either version 3,  or (at your option) any later ver- --

-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --

-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --

-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --

-- for  more details.  You should have  received  a copy of the GNU General --

-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --

-- http://www.gnu.org/licenses for a complete copy of the license.          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

--  This package contains various utility procedures to assist in building

--  specific types of tree nodes.

with Namet; use Namet;

with Sinfo; use Sinfo;

with Types; use Types;

with Uintp; use Uintp;

package Tbuild is

   function Checks_Off (N : Node_Id) return Node_Id;

   pragma Inline (Checks_Off);

   --  Returns an N_Unchecked_Expression node whose expression is the given

   --  argument. The results is a subexpression identical to the argument,

   --  except that it will be analyzed and resolved with checks off.

   function Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;

   --  Returns an expression that represents the result of a checked convert

   --  of expression Exp to type T. If the base type of Exp is T, then no

   --  conversion is required, and Exp is returned unchanged. Otherwise an

   --  N_Type_Conversion node is constructed to convert the expression.

   --  If an N_Type_Conversion node is required, Relocate_Node is used on

   --  Exp. This means that it is safe to replace a node by a Convert_To

   --  of itself to some other type.

   procedure Discard_Node (N : Node_Or_Entity_Id);

   pragma Inline (Discard_Node);

   --  This is a dummy procedure that simply returns and does nothing. It is

   --  used when a function returning a Node_Id value is called for its side

   --  effect (e.g. a call to Make to construct a node) but the Node_Id value

   --  is not required.

   procedure Discard_List (L : List_Id);

   pragma Inline (Discard_List);

   --  This is a dummy procedure that simply returns and does nothing. It is

   --  used when a function returning a Node_Id value is called for its side

   --  effect (e.g. a call to the parser to parse a list of compilation

   --  units), but the List_Id value is not required.

   function Make_Byte_Aligned_Attribute_Reference

     (Sloc           : Source_Ptr;

      Prefix         : Node_Id;

      Attribute_Name : Name_Id) return Node_Id;

   pragma Inline (Make_Byte_Aligned_Attribute_Reference);

   --  Like the standard Make_Attribute_Reference but the special flag

   --  Must_Be_Byte_Aligned is set in the attribute reference node. The

   --  Attribute_Name must be Name_Address or Name_Unrestricted_Access.

   function Make_DT_Access

     (Loc : Source_Ptr; Rec : Node_Id; Typ : Entity_Id) return Node_Id;

   --  Create an access to the Dispatch Table by using the Tag field of a

   --  tagged record : Acc_Dt (Rec.tag).all

   function Make_Float_Literal

     (Loc         : Source_Ptr;

      Radix       : Uint;

      Significand : Uint;

      Exponent    : Uint) return Node_Id;

   --  Create a real literal for the floating point expression value

   --  Significand * Radix ** Exponent. Radix must be greater than 1.

   function Make_Implicit_Exception_Handler

     (Sloc              : Source_Ptr;

      Choice_Parameter  : Node_Id := Empty;

      Exception_Choices : List_Id;

      Statements        : List_Id) return Node_Id;

   pragma Inline (Make_Implicit_Exception_Handler);

   --  This is just like Make_Exception_Handler, except that it also sets the

   --  Local_Raise_Statements field to No_Elist, ensuring that it is properly

   --  initialized. This should always be used when creating implicit exception

   --  handlers during expansion (i.e. handlers that do not correspond to user

   --  source program exception handlers).

   function Make_Implicit_If_Statement

     (Node            : Node_Id;

      Condition       : Node_Id;

      Then_Statements : List_Id;

      Elsif_Parts     : List_Id := No_List;

      Else_Statements : List_Id := No_List) return Node_Id;

   pragma Inline (Make_Implicit_If_Statement);

   --  This function makes an N_If_Statement node whose fields are filled

   --  in with the indicated values (see Sinfo), and whose Sloc field is

   --  is set to Sloc (Node). The effect is identical to calling function

   --  Nmake.Make_If_Statement except that there is a check for restriction

   --  No_Implicit_Conditionals, and if this restriction is being violated,

   --  an error message is posted on Node.

   function Make_Implicit_Label_Declaration

     (Loc                 : Source_Ptr;

      Defining_Identifier : Node_Id;

      Label_Construct     : Node_Id) return Node_Id;

   --  Used to construct an implicit label declaration node, including setting

   --  the proper Label_Construct field (since Label_Construct is a semantic

   --  field, the normal call to Make_Implicit_Label_Declaration does not

   --  set this field).

   function Make_Implicit_Loop_Statement

     (Node                   : Node_Id;

      Statements             : List_Id;

      Identifier             : Node_Id := Empty;

      Iteration_Scheme       : Node_Id := Empty;

      Has_Created_Identifier : Boolean := False;

      End_Label              : Node_Id := Empty) return Node_Id;

   --  This function makes an N_Loop_Statement node whose fields are filled

   --  in with the indicated values (see Sinfo), and whose Sloc field is

   --  is set to Sloc (Node). The effect is identical to calling function

   --  Nmake.Make_Loop_Statement except that there is a check for restrictions

   --  No_Implicit_Loops and No_Implicit_Conditionals (the first applying in

   --  all cases, and the second only for while loops), and if one of these

   --  restrictions is being violated, an error message is posted on Node.

   function Make_Integer_Literal

     (Loc    : Source_Ptr;

      Intval : Int) return Node_Id;

   pragma Inline (Make_Integer_Literal);

   --  A convenient form of Make_Integer_Literal taking Int instead of Uint

   function Make_Linker_Section_Pragma

     (Ent : Entity_Id;

      Loc : Source_Ptr;

      Sec : String) return Node_Id;

   --  Construct a Linker_Section pragma for entity Ent, using string Sec as

   --  the section name. Loc is the Sloc value to use in building the pragma.

   function Make_Pragma

     (Sloc                         : Source_Ptr;

      Chars                        : Name_Id;

      Pragma_Argument_Associations : List_Id := No_List) return Node_Id;

   --  A convenient form of Make_Pragma not requiring a Pragma_Identifier

   --  argument (this argument is built from the value given for Chars).

   function Make_Raise_Constraint_Error

     (Sloc      : Source_Ptr;

      Condition : Node_Id := Empty;

      Reason    : RT_Exception_Code) return Node_Id;

   pragma Inline (Make_Raise_Constraint_Error);

   --  A convenient form of Make_Raise_Constraint_Error where the Reason

   --  is given simply as an enumeration value, rather than a Uint code.

   function Make_Raise_Program_Error

     (Sloc      : Source_Ptr;

      Condition : Node_Id := Empty;

      Reason    : RT_Exception_Code) return Node_Id;

   pragma Inline (Make_Raise_Program_Error);

   --  A convenient form of Make_Raise_Program_Error where the Reason

   --  is given simply as an enumeration value, rather than a Uint code.

   function Make_Raise_Storage_Error

     (Sloc      : Source_Ptr;

      Condition : Node_Id := Empty;

      Reason    : RT_Exception_Code) return Node_Id;

   pragma Inline (Make_Raise_Storage_Error);

   --  A convenient form of Make_Raise_Storage_Error where the Reason is given

   --  simply as an enumeration value, rather than a Uint code.

   function Make_String_Literal

     (Sloc   : Source_Ptr;

      Strval : String) return Node_Id;

   --  A convenient form of Make_String_Literal, where the string value is

   --  given as a normal string instead of a String_Id value.

   function Make_Temporary

     (Loc          : Source_Ptr;

      Id           : Character;

      Related_Node : Node_Id := Empty) return Entity_Id;

   --  This function should be used for all cases where a defining identifier

   --  is to be built with a name to be obtained by New_Internal_Name (here Id

   --  is the character passed as the argument to New_Internal_Name). Loc is

   --  the location for the Sloc value of the resulting Entity. Note that this

   --  can be used for all kinds of temporary defining identifiers used in

   --  expansion (objects, subtypes, functions etc).

   --

   --  Related_Node is used when the defining identifier is for an object that

   --  captures the value of an expression (e.g. an aggregate). It should be

   --  set whenever possible to point to the expression that is being captured.

   --  This is provided to get better error messages, e.g. from CodePeer.

   --

   --  Make_Temp_Id would probably be a better name for this function???

   function Make_Unsuppress_Block

     (Loc   : Source_Ptr;

      Check : Name_Id;

      Stmts : List_Id) return Node_Id;

   --  Build a block with a pragma Suppress on 'Check'. Stmts is the statements

   --  list that needs protection against the check

   function New_Constraint_Error (Loc : Source_Ptr) return Node_Id;

   --  This function builds a tree corresponding to the Ada statement

   --  "raise Constraint_Error" and returns the root of this tree,

   --  the N_Raise_Statement node.

   function New_Op_Node

     (New_Node_Kind : Node_Kind;

      New_Sloc      : Source_Ptr) return Node_Id;

   --  Create node using New_Node and, if its kind is in N_Op, set its Chars

   --  field accordingly.

   function New_External_Name

     (Related_Id   : Name_Id;

      Suffix       : Character := ' ';

      Suffix_Index : Int       := 0;

      Prefix       : Character := ' ') return Name_Id;

   function New_External_Name

     (Related_Id   : Name_Id;

      Suffix       : String;

      Suffix_Index : Int       := 0;

      Prefix       : Character := ' ') return Name_Id;

   --  Builds a new entry in the names table of the form:

   --

   --    [Prefix  &] Related_Id [& Suffix] [& Suffix_Index]

   --

   --  Prefix is prepended only if Prefix is non-blank (in which case it

   --  must be an upper case letter other than O,Q,U,W (which are used for

   --  identifier encoding, see Namet), or an underscore, and T is reserved for

   --  use by implicit types, and X is reserved for use by debug type encoding

   --  (see package Exp_Dbug). Note: the reason that Prefix is last is that it

   --  is almost always omitted. The notable case of Prefix being non-null is

   --  when it is 'T' for an implicit type.

   --  Suffix_Index'Image is appended only if the value of Suffix_Index is

   --  positive, or if Suffix_Index is negative 1, then a unique serialized

   --  suffix is added. If Suffix_Index is zero, then no index is appended.

   --  Suffix is also a single upper case letter other than O,Q,U,W,X and is a

   --  required parameter (T is permitted). The constructed name is stored

   --  using Name_Find so that it can be located using a subsequent Name_Find

   --  operation (i.e. it is properly hashed into the names table). The upper

   --  case letter given as the Suffix argument ensures that the name does

   --  not clash with any Ada identifier name. These generated names are

   --  permitted, but not required, to be made public by setting the flag

   --  Is_Public in the associated entity.

   function New_External_Name

     (Suffix       : Character;

      Suffix_Index : Nat) return Name_Id;

   --  Builds a new entry in the names table of the form

   --    Suffix & Suffix_Index'Image

   --  where Suffix is a single upper case letter other than O,Q,U,W,X and is

   --  a required parameter (T is permitted). The constructed name is stored

   --  using Name_Find so that it can be located using a subsequent Name_Find

   --  operation (i.e. it is properly hashed into the names table). The upper

   --  case letter given as the Suffix argument ensures that the name does

   --  not clash with any Ada identifier name. These generated names are

   --  permitted, but not required, to be made public by setting the flag

   --  Is_Public in the associated entity.

   function New_Internal_Name (Id_Char : Character) return Name_Id;

   --  Id_Char is an upper case letter other than O,Q,U,W (which are reserved

   --  for identifier encoding (see Namet package for details) and X which is

   --  used for debug encoding (see Exp_Dbug). The letter T is permitted, but

   --  is reserved by convention for the case of internally generated types.

   --  The result of the call is a new generated unique name of the form XyyyU

   --  where X is Id_Char, yyy is a unique serial number, and U is either a

   --  lower case s or b indicating if the current unit is a spec or a body.

   --

   --  The name is entered into the names table using Name_Enter rather than

   --  Name_Find, because there can never be a need to locate the entry using

   --  the Name_Find procedure later on. Names created by New_Internal_Name

   --  are guaranteed to be consistent from one compilation to another (i.e.

   --  if the identical unit is compiled with a semantically consistent set

   --  of sources, the numbers will be consistent. This means that it is fine

   --  to use these as public symbols.

   --

   --  Note: Nearly all uses of this function are via calls to Make_Temporary,

   --  but there are just a few cases where it is called directly.

   function New_Occurrence_Of

     (Def_Id : Entity_Id;

      Loc    : Source_Ptr) return Node_Id;

   --  New_Occurrence_Of creates an N_Identifier node which is an occurrence

   --  of the defining identifier which is passed as its argument. The Entity

   --  and Etype of the result are set from the given defining identifier as

   --  follows: Entity is simply a copy of Def_Id. Etype is a copy of Def_Id

   --  for types, and a copy of the Etype of Def_Id for other entities.

   function New_Reference_To

     (Def_Id : Entity_Id;

      Loc    : Source_Ptr) return Node_Id;

   --  This is like New_Occurrence_Of, but it does not set the Etype field. It

   --  is used from the expander, where Etype fields are generally not set,

   --  since they are set when the expanded tree is reanalyzed.

   function New_Suffixed_Name

     (Related_Id : Name_Id;

      Suffix     : String) return Name_Id;

   --  This function is used to create special suffixed names used by the

   --  debugger. Suffix is a string of upper case letters, used to construct

   --  the required name. For instance, the special type used to record the

   --  fixed-point small is called typ_SMALL where typ is the name of the

   --  fixed-point type (as passed in Related_Id), and Suffix is "SMALL".

   function OK_Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;

   --  Like Convert_To, except that a conversion node is always generated, and

   --  the Conversion_OK flag is set on this conversion node.

   function Unchecked_Convert_To

     (Typ  : Entity_Id;

      Expr : Node_Id) return Node_Id;

   --  Like Convert_To, but if a conversion is actually needed, constructs an

   --  N_Unchecked_Type_Conversion node to do the required conversion.

end Tbuild;