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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) 1992-2010, 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 building
  27 --  specific types of tree nodes.
  28
  29 with Namet; use Namet;
  30 with Sinfo; use Sinfo;
  31 with Types; use Types;
  32 with Uintp; use Uintp;
  33
  34 package Tbuild is
  35
  36    function Checks_Off (N : Node_Id) return Node_Id;
  37    pragma Inline (Checks_Off);
  38    --  Returns an N_Unchecked_Expression node whose expression is the given
  39    --  argument. The results is a subexpression identical to the argument,
  40    --  except that it will be analyzed and resolved with checks off.
  41
  42    function Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
  43    --  Returns an expression that represents the result of a checked convert
  44    --  of expression Exp to type T. If the base type of Exp is T, then no
  45    --  conversion is required, and Exp is returned unchanged. Otherwise an
  46    --  N_Type_Conversion node is constructed to convert the expression.
  47    --  If an N_Type_Conversion node is required, Relocate_Node is used on
  48    --  Exp. This means that it is safe to replace a node by a Convert_To
  49    --  of itself to some other type.
  50
  51    procedure Discard_Node (N : Node_Or_Entity_Id);
  52    pragma Inline (Discard_Node);
  53    --  This is a dummy procedure that simply returns and does nothing. It is
  54    --  used when a function returning a Node_Id value is called for its side
  55    --  effect (e.g. a call to Make to construct a node) but the Node_Id value
  56    --  is not required.
  57
  58    procedure Discard_List (L : List_Id);
  59    pragma Inline (Discard_List);
  60    --  This is a dummy procedure that simply returns and does nothing. It is
  61    --  used when a function returning a Node_Id value is called for its side
  62    --  effect (e.g. a call to the parser to parse a list of compilation
  63    --  units), but the List_Id value is not required.
  64
  65    function Make_Byte_Aligned_Attribute_Reference
  66      (Sloc           : Source_Ptr;
  67       Prefix         : Node_Id;
  68       Attribute_Name : Name_Id) return Node_Id;
  69    pragma Inline (Make_Byte_Aligned_Attribute_Reference);
  70    --  Like the standard Make_Attribute_Reference but the special flag
  71    --  Must_Be_Byte_Aligned is set in the attribute reference node. The
  72    --  Attribute_Name must be Name_Address or Name_Unrestricted_Access.
  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 of a
  77    --  tagged record : Acc_Dt (Rec.tag).all
  78
  79    function Make_Float_Literal
  80      (Loc         : Source_Ptr;
  81       Radix       : Uint;
  82       Significand : Uint;
  83       Exponent    : Uint) return Node_Id;
  84    --  Create a real literal for the floating point expression value
  85    --  Significand * Radix ** Exponent. Radix must be greater than 1.
  86
  87    function Make_Implicit_Exception_Handler
  88      (Sloc              : Source_Ptr;
  89       Choice_Parameter  : Node_Id := Empty;
  90       Exception_Choices : List_Id;
  91       Statements        : List_Id) return Node_Id;
  92    pragma Inline (Make_Implicit_Exception_Handler);
  93    --  This is just like Make_Exception_Handler, except that it also sets the
  94    --  Local_Raise_Statements field to No_Elist, ensuring that it is properly
  95    --  initialized. This should always be used when creating implicit exception
  96    --  handlers during expansion (i.e. handlers that do not correspond to user
  97    --  source program exception handlers).
  98
  99    function Make_Implicit_If_Statement
 100      (Node            : Node_Id;
 101       Condition       : Node_Id;
 102       Then_Statements : List_Id;
 103       Elsif_Parts     : List_Id := No_List;
 104       Else_Statements : List_Id := No_List) return Node_Id;
 105    pragma Inline (Make_Implicit_If_Statement);
 106    --  This function makes an N_If_Statement node whose fields are filled
 107    --  in with the indicated values (see Sinfo), and whose Sloc field is
 108    --  is set to Sloc (Node). The effect is identical to calling function
 109    --  Nmake.Make_If_Statement except that there is a check for restriction
 110    --  No_Implicit_Conditionals, and if this restriction is being violated,
 111    --  an error message is posted on Node.
 112
 113    function Make_Implicit_Label_Declaration
 114      (Loc                 : Source_Ptr;
 115       Defining_Identifier : Node_Id;
 116       Label_Construct     : Node_Id) return Node_Id;
 117    --  Used to construct an implicit label declaration node, including setting
 118    --  the proper Label_Construct field (since Label_Construct is a semantic
 119    --  field, the normal call to Make_Implicit_Label_Declaration does not
 120    --  set this field).
 121
 122    function Make_Implicit_Loop_Statement
 123      (Node                   : Node_Id;
 124       Statements             : List_Id;
 125       Identifier             : Node_Id := Empty;
 126       Iteration_Scheme       : Node_Id := Empty;
 127       Has_Created_Identifier : Boolean := False;
 128       End_Label              : Node_Id := Empty) return Node_Id;
 129    --  This function makes an N_Loop_Statement node whose fields are filled
 130    --  in with the indicated values (see Sinfo), and whose Sloc field is
 131    --  is set to Sloc (Node). The effect is identical to calling function
 132    --  Nmake.Make_Loop_Statement except that there is a check for restrictions
 133    --  No_Implicit_Loops and No_Implicit_Conditionals (the first applying in
 134    --  all cases, and the second only for while loops), and if one of these
 135    --  restrictions is being violated, an error message is posted on Node.
 136
 137    function Make_Integer_Literal
 138      (Loc    : Source_Ptr;
 139       Intval : Int) return Node_Id;
 140    pragma Inline (Make_Integer_Literal);
 141    --  A convenient form of Make_Integer_Literal taking Int instead of Uint
 142
 143    function Make_Linker_Section_Pragma
 144      (Ent : Entity_Id;
 145       Loc : Source_Ptr;
 146       Sec : String) return Node_Id;
 147    --  Construct a Linker_Section pragma for entity Ent, using string Sec as
 148    --  the section name. Loc is the Sloc value to use in building the pragma.
 149
 150    function Make_Pragma
 151      (Sloc                         : Source_Ptr;
 152       Chars                        : Name_Id;
 153       Pragma_Argument_Associations : List_Id := No_List;
 154       Debug_Statement              : Node_Id := Empty) return Node_Id;
 155    --  A convenient form of Make_Pragma not requiring a Pragma_Identifier
 156    --  argument (this argument is built from the value given for Chars).
 157
 158    function Make_Raise_Constraint_Error
 159      (Sloc      : Source_Ptr;
 160       Condition : Node_Id := Empty;
 161       Reason    : RT_Exception_Code) return Node_Id;
 162    pragma Inline (Make_Raise_Constraint_Error);
 163    --  A convenient form of Make_Raise_Constraint_Error where the Reason
 164    --  is given simply as an enumeration value, rather than a Uint code.
 165
 166    function Make_Raise_Program_Error
 167      (Sloc      : Source_Ptr;
 168       Condition : Node_Id := Empty;
 169       Reason    : RT_Exception_Code) return Node_Id;
 170    pragma Inline (Make_Raise_Program_Error);
 171    --  A convenient form of Make_Raise_Program_Error where the Reason
 172    --  is given simply as an enumeration value, rather than a Uint code.
 173
 174    function Make_Raise_Storage_Error
 175      (Sloc      : Source_Ptr;
 176       Condition : Node_Id := Empty;
 177       Reason    : RT_Exception_Code) return Node_Id;
 178    pragma Inline (Make_Raise_Storage_Error);
 179    --  A convenient form of Make_Raise_Storage_Error where the Reason is given
 180    --  simply as an enumeration value, rather than a Uint code.
 181
 182    function Make_String_Literal
 183      (Sloc   : Source_Ptr;
 184       Strval : String) return Node_Id;
 185    --  A convenient form of Make_String_Literal, where the string value is
 186    --  given as a normal string instead of a String_Id value.
 187
 188    function Make_Temporary
 189      (Loc          : Source_Ptr;
 190       Id           : Character;
 191       Related_Node : Node_Id := Empty) return Entity_Id;
 192    --  This function should be used for all cases where a defining identifier
 193    --  is to be built with a name to be obtained by New_Internal_Name (here Id
 194    --  is the character passed as the argument to New_Internal_Name). Loc is
 195    --  the location for the Sloc value of the resulting Entity. Note that this
 196    --  can be used for all kinds of temporary defining identifiers used in
 197    --  expansion (objects, subtypes, functions etc).
 198    --
 199    --  Related_Node is used when the defining identifier is for an object that
 200    --  captures the value of an expression (e.g. an aggregate). It should be
 201    --  set whenever possible to point to the expression that is being captured.
 202    --  This is provided to get better error messages, e.g. from CodePeer.
 203    --
 204    --  Make_Temp_Id would probably be a better name for this function???
 205
 206    function Make_Unsuppress_Block
 207      (Loc   : Source_Ptr;
 208       Check : Name_Id;
 209       Stmts : List_Id) return Node_Id;
 210    --  Build a block with a pragma Suppress on 'Check'. Stmts is the statements
 211    --  list that needs protection against the check
 212
 213    function New_Constraint_Error (Loc : Source_Ptr) return Node_Id;
 214    --  This function builds a tree corresponding to the Ada statement
 215    --  "raise Constraint_Error" and returns the root of this tree,
 216    --  the N_Raise_Statement node.
 217
 218    function New_Op_Node
 219      (New_Node_Kind : Node_Kind;
 220       New_Sloc      : Source_Ptr) return Node_Id;
 221    --  Create node using New_Node and, if its kind is in N_Op, set its Chars
 222    --  field accordingly.
 223
 224    function New_External_Name
 225      (Related_Id   : Name_Id;
 226       Suffix       : Character := ' ';
 227       Suffix_Index : Int       := 0;
 228       Prefix       : Character := ' ') return Name_Id;
 229    function New_External_Name
 230      (Related_Id   : Name_Id;
 231       Suffix       : String;
 232       Suffix_Index : Int       := 0;
 233       Prefix       : Character := ' ') return Name_Id;
 234    --  Builds a new entry in the names table of the form:
 235    --
 236    --    [Prefix  &] Related_Id [& Suffix] [& Suffix_Index]
 237    --
 238    --  Prefix is prepended only if Prefix is non-blank (in which case it
 239    --  must be an upper case letter other than O,Q,U,W (which are used for
 240    --  identifier encoding, see Namet), or an underscore, and T is reserved for
 241    --  use by implicit types, and X is reserved for use by debug type encoding
 242    --  (see package Exp_Dbug). Note: the reason that Prefix is last is that it
 243    --  is almost always omitted. The notable case of Prefix being non-null is
 244    --  when it is 'T' for an implicit type.
 245
 246    --  Suffix_Index'Image is appended only if the value of Suffix_Index is
 247    --  positive, or if Suffix_Index is negative 1, then a unique serialized
 248    --  suffix is added. If Suffix_Index is zero, then no index is appended.
 249
 250    --  Suffix is also a single upper case letter other than O,Q,U,W,X and is a
 251    --  required parameter (T is permitted). The constructed name is stored
 252    --  using Name_Find so that it can be located using a subsequent Name_Find
 253    --  operation (i.e. it is properly hashed into the names table). The upper
 254    --  case letter given as the Suffix argument ensures that the name does
 255    --  not clash with any Ada identifier name. These generated names are
 256    --  permitted, but not required, to be made public by setting the flag
 257    --  Is_Public in the associated entity.
 258
 259    function New_External_Name
 260      (Suffix       : Character;
 261       Suffix_Index : Nat) return Name_Id;
 262    --  Builds a new entry in the names table of the form
 263    --    Suffix & Suffix_Index'Image
 264    --  where Suffix is a single upper case letter other than O,Q,U,W,X and is
 265    --  a required parameter (T is permitted). The constructed name is stored
 266    --  using Name_Find so that it can be located using a subsequent Name_Find
 267    --  operation (i.e. it is properly hashed into the names table). The upper
 268    --  case letter given as the Suffix argument ensures that the name does
 269    --  not clash with any Ada identifier name. These generated names are
 270    --  permitted, but not required, to be made public by setting the flag
 271    --  Is_Public in the associated entity.
 272
 273    function New_Internal_Name (Id_Char : Character) return Name_Id;
 274    --  Id_Char is an upper case letter other than O,Q,U,W (which are reserved
 275    --  for identifier encoding (see Namet package for details) and X which is
 276    --  used for debug encoding (see Exp_Dbug). The letter T is permitted, but
 277    --  is reserved by convention for the case of internally generated types.
 278    --  The result of the call is a new generated unique name of the form XyyyU
 279    --  where X is Id_Char, yyy is a unique serial number, and U is either a
 280    --  lower case s or b indicating if the current unit is a spec or a body.
 281    --
 282    --  The name is entered into the names table using Name_Enter rather than
 283    --  Name_Find, because there can never be a need to locate the entry using
 284    --  the Name_Find procedure later on. Names created by New_Internal_Name
 285    --  are guaranteed to be consistent from one compilation to another (i.e.
 286    --  if the identical unit is compiled with a semantically consistent set
 287    --  of sources, the numbers will be consistent. This means that it is fine
 288    --  to use these as public symbols.
 289    --
 290    --  Note: Nearly all uses of this function are via calls to Make_Temporary,
 291    --  but there are just a few cases where it is called directly.
 292
 293    function New_Occurrence_Of
 294      (Def_Id : Entity_Id;
 295       Loc    : Source_Ptr) return Node_Id;
 296    --  New_Occurrence_Of creates an N_Identifier node which is an occurrence
 297    --  of the defining identifier which is passed as its argument. The Entity
 298    --  and Etype of the result are set from the given defining identifier as
 299    --  follows: Entity is simply a copy of Def_Id. Etype is a copy of Def_Id
 300    --  for types, and a copy of the Etype of Def_Id for other entities.
 301
 302    function New_Reference_To
 303      (Def_Id : Entity_Id;
 304       Loc    : Source_Ptr) return Node_Id;
 305    --  This is like New_Occurrence_Of, but it does not set the Etype field. It
 306    --  is used from the expander, where Etype fields are generally not set,
 307    --  since they are set when the expanded tree is reanalyzed.
 308
 309    function New_Suffixed_Name
 310      (Related_Id : Name_Id;
 311       Suffix     : String) return Name_Id;
 312    --  This function is used to create special suffixed names used by the
 313    --  debugger. Suffix is a string of upper case letters, used to construct
 314    --  the required name. For instance, the special type used to record the
 315    --  fixed-point small is called typ_SMALL where typ is the name of the
 316    --  fixed-point type (as passed in Related_Id), and Suffix is "SMALL".
 317
 318    function OK_Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
 319    --  Like Convert_To, except that a conversion node is always generated, and
 320    --  the Conversion_OK flag is set on this conversion node.
 321
 322    function Unchecked_Convert_To
 323      (Typ  : Entity_Id;
 324       Expr : Node_Id) return Node_Id;
 325    --  Like Convert_To, but if a conversion is actually needed, constructs an
 326    --  N_Unchecked_Type_Conversion node to do the required conversion.
 327
 328 end Tbuild;