1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                               T B U I L D                                --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2013, 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
29with Namet; use Namet;
30with Sinfo; use Sinfo;
31with Types; use Types;
32with Uintp; use Uintp;
33
34package 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 Convert_To_And_Rewrite (Typ : Entity_Id; Expr : Node_Id);
52   pragma Inline (Convert_To_And_Rewrite);
53   --  Like the function, except that there is an extra step of calling
54   --  Rewrite on the Expr node and replacing it with the converted result.
55   --  As noted above, this is safe, because Relocate_Node is called.
56
57   procedure Discard_Node (N : Node_Or_Entity_Id);
58   pragma Inline (Discard_Node);
59   --  This is a dummy procedure that simply returns and does nothing. It is
60   --  used when a function returning a Node_Id value is called for its side
61   --  effect (e.g. a call to Make to construct a node) but the Node_Id value
62   --  is not required.
63
64   procedure Discard_List (L : List_Id);
65   pragma Inline (Discard_List);
66   --  This is a dummy procedure that simply returns and does nothing. It is
67   --  used when a function returning a Node_Id value is called for its side
68   --  effect (e.g. a call to the parser to parse a list of compilation
69   --  units), but the List_Id value is not required.
70
71   function Make_Byte_Aligned_Attribute_Reference
72     (Sloc           : Source_Ptr;
73      Prefix         : Node_Id;
74      Attribute_Name : Name_Id) return Node_Id;
75   pragma Inline (Make_Byte_Aligned_Attribute_Reference);
76   --  Like the standard Make_Attribute_Reference but the special flag
77   --  Must_Be_Byte_Aligned is set in the attribute reference node. The
78   --  Attribute_Name must be Name_Address or Name_Unrestricted_Access.
79
80   function Make_DT_Access
81     (Loc : Source_Ptr; Rec : Node_Id; Typ : Entity_Id) return Node_Id;
82   --  Create an access to the Dispatch Table by using the Tag field of a
83   --  tagged record : Acc_Dt (Rec.tag).all
84
85   function Make_Float_Literal
86     (Loc         : Source_Ptr;
87      Radix       : Uint;
88      Significand : Uint;
89      Exponent    : Uint) return Node_Id;
90   --  Create a real literal for the floating point expression value
91   --  Significand * Radix ** Exponent. Radix must be greater than 1.
92
93   function Make_Implicit_Exception_Handler
94     (Sloc              : Source_Ptr;
95      Choice_Parameter  : Node_Id := Empty;
96      Exception_Choices : List_Id;
97      Statements        : List_Id) return Node_Id;
98   pragma Inline (Make_Implicit_Exception_Handler);
99   --  This is just like Make_Exception_Handler, except that it also sets the
100   --  Local_Raise_Statements field to No_Elist, ensuring that it is properly
101   --  initialized. This should always be used when creating implicit exception
102   --  handlers during expansion (i.e. handlers that do not correspond to user
103   --  source program exception handlers).
104
105   function Make_Implicit_If_Statement
106     (Node            : Node_Id;
107      Condition       : Node_Id;
108      Then_Statements : List_Id;
109      Elsif_Parts     : List_Id := No_List;
110      Else_Statements : List_Id := No_List) return Node_Id;
111   pragma Inline (Make_Implicit_If_Statement);
112   --  This function makes an N_If_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_If_Statement except that there is a check for restriction
116   --  No_Implicit_Conditionals, and if this restriction is being violated,
117   --  an error message is posted on Node.
118
119   function Make_Implicit_Label_Declaration
120     (Loc                 : Source_Ptr;
121      Defining_Identifier : Node_Id;
122      Label_Construct     : Node_Id) return Node_Id;
123   --  Used to construct an implicit label declaration node, including setting
124   --  the proper Label_Construct field (since Label_Construct is a semantic
125   --  field, the normal call to Make_Implicit_Label_Declaration does not
126   --  set this field).
127
128   function Make_Implicit_Loop_Statement
129     (Node                   : Node_Id;
130      Statements             : List_Id;
131      Identifier             : Node_Id := Empty;
132      Iteration_Scheme       : Node_Id := Empty;
133      Has_Created_Identifier : Boolean := False;
134      End_Label              : Node_Id := Empty) return Node_Id;
135   --  This function makes an N_Loop_Statement node whose fields are filled
136   --  in with the indicated values (see Sinfo), and whose Sloc field is
137   --  is set to Sloc (Node). The effect is identical to calling function
138   --  Nmake.Make_Loop_Statement except that there is a check for restrictions
139   --  No_Implicit_Loops and No_Implicit_Conditionals (the first applying in
140   --  all cases, and the second only for while loops), and if one of these
141   --  restrictions is being violated, an error message is posted on Node.
142
143   function Make_Integer_Literal
144     (Loc    : Source_Ptr;
145      Intval : Int) return Node_Id;
146   pragma Inline (Make_Integer_Literal);
147   --  A convenient form of Make_Integer_Literal taking Int instead of Uint
148
149   function Make_Linker_Section_Pragma
150     (Ent : Entity_Id;
151      Loc : Source_Ptr;
152      Sec : String) return Node_Id;
153   --  Construct a Linker_Section pragma for entity Ent, using string Sec as
154   --  the section name. Loc is the Sloc value to use in building the pragma.
155
156   function Make_Pragma
157     (Sloc                         : Source_Ptr;
158      Chars                        : Name_Id;
159      Pragma_Argument_Associations : List_Id := No_List) return Node_Id;
160   --  A convenient form of Make_Pragma not requiring a Pragma_Identifier
161   --  argument (this argument is built from the value given for Chars).
162
163   function Make_Raise_Constraint_Error
164     (Sloc      : Source_Ptr;
165      Condition : Node_Id := Empty;
166      Reason    : RT_Exception_Code) return Node_Id;
167   pragma Inline (Make_Raise_Constraint_Error);
168   --  A convenient form of Make_Raise_Constraint_Error where the Reason
169   --  is given simply as an enumeration value, rather than a Uint code.
170
171   function Make_Raise_Program_Error
172     (Sloc      : Source_Ptr;
173      Condition : Node_Id := Empty;
174      Reason    : RT_Exception_Code) return Node_Id;
175   pragma Inline (Make_Raise_Program_Error);
176   --  A convenient form of Make_Raise_Program_Error where the Reason
177   --  is given simply as an enumeration value, rather than a Uint code.
178
179   function Make_Raise_Storage_Error
180     (Sloc      : Source_Ptr;
181      Condition : Node_Id := Empty;
182      Reason    : RT_Exception_Code) return Node_Id;
183   pragma Inline (Make_Raise_Storage_Error);
184   --  A convenient form of Make_Raise_Storage_Error where the Reason is given
185   --  simply as an enumeration value, rather than a Uint code.
186
187   function Make_String_Literal
188     (Sloc   : Source_Ptr;
189      Strval : String) return Node_Id;
190   --  A convenient form of Make_String_Literal, where the string value is
191   --  given as a normal string instead of a String_Id value.
192
193   function Make_Temporary
194     (Loc          : Source_Ptr;
195      Id           : Character;
196      Related_Node : Node_Id := Empty) return Entity_Id;
197   --  This function should be used for all cases where a defining identifier
198   --  is to be built with a name to be obtained by New_Internal_Name (here Id
199   --  is the character passed as the argument to New_Internal_Name). Loc is
200   --  the location for the Sloc value of the resulting Entity. Note that this
201   --  can be used for all kinds of temporary defining identifiers used in
202   --  expansion (objects, subtypes, functions etc).
203   --
204   --  Related_Node is used when the defining identifier is for an object that
205   --  captures the value of an expression (e.g. an aggregate). It should be
206   --  set whenever possible to point to the expression that is being captured.
207   --  This is provided to get better error messages, e.g. from CodePeer.
208   --
209   --  Make_Temp_Id would probably be a better name for this function???
210
211   function Make_Unsuppress_Block
212     (Loc   : Source_Ptr;
213      Check : Name_Id;
214      Stmts : List_Id) return Node_Id;
215   --  Build a block with a pragma Suppress on 'Check'. Stmts is the statements
216   --  list that needs protection against the check
217
218   function New_Constraint_Error (Loc : Source_Ptr) return Node_Id;
219   --  This function builds a tree corresponding to the Ada statement
220   --  "raise Constraint_Error" and returns the root of this tree,
221   --  the N_Raise_Statement node.
222
223   function New_Op_Node
224     (New_Node_Kind : Node_Kind;
225      New_Sloc      : Source_Ptr) return Node_Id;
226   --  Create node using New_Node and, if its kind is in N_Op, set its Chars
227   --  field accordingly.
228
229   function New_External_Name
230     (Related_Id   : Name_Id;
231      Suffix       : Character := ' ';
232      Suffix_Index : Int       := 0;
233      Prefix       : Character := ' ') return Name_Id;
234   function New_External_Name
235     (Related_Id   : Name_Id;
236      Suffix       : String;
237      Suffix_Index : Int       := 0;
238      Prefix       : Character := ' ') return Name_Id;
239   --  Builds a new entry in the names table of the form:
240   --
241   --    [Prefix  &] Related_Id [& Suffix] [& Suffix_Index]
242   --
243   --  Prefix is prepended only if Prefix is non-blank (in which case it
244   --  must be an upper case letter other than O,Q,U,W (which are used for
245   --  identifier encoding, see Namet), or an underscore, and T is reserved for
246   --  use by implicit types, and X is reserved for use by debug type encoding
247   --  (see package Exp_Dbug). Note: the reason that Prefix is last is that it
248   --  is almost always omitted. The notable case of Prefix being non-null is
249   --  when it is 'T' for an implicit type.
250
251   --  Suffix_Index'Image is appended only if the value of Suffix_Index is
252   --  positive, or if Suffix_Index is negative 1, then a unique serialized
253   --  suffix is added. If Suffix_Index is zero, then no index is appended.
254
255   --  Suffix is also a single upper case letter other than O,Q,U,W,X and is a
256   --  required parameter (T is permitted). The constructed name is stored
257   --  using Name_Find so that it can be located using a subsequent Name_Find
258   --  operation (i.e. it is properly hashed into the names table). The upper
259   --  case letter given as the Suffix argument ensures that the name does
260   --  not clash with any Ada identifier name. These generated names are
261   --  permitted, but not required, to be made public by setting the flag
262   --  Is_Public in the associated entity.
263
264   function New_External_Name
265     (Suffix       : Character;
266      Suffix_Index : Nat) return Name_Id;
267   --  Builds a new entry in the names table of the form
268   --    Suffix & Suffix_Index'Image
269   --  where Suffix is a single upper case letter other than O,Q,U,W,X and is
270   --  a required parameter (T is permitted). The constructed name is stored
271   --  using Name_Find so that it can be located using a subsequent Name_Find
272   --  operation (i.e. it is properly hashed into the names table). The upper
273   --  case letter given as the Suffix argument ensures that the name does
274   --  not clash with any Ada identifier name. These generated names are
275   --  permitted, but not required, to be made public by setting the flag
276   --  Is_Public in the associated entity.
277
278   function New_Internal_Name (Id_Char : Character) return Name_Id;
279   --  Id_Char is an upper case letter other than O,Q,U,W (which are reserved
280   --  for identifier encoding (see Namet package for details) and X which is
281   --  used for debug encoding (see Exp_Dbug). The letter T is permitted, but
282   --  is reserved by convention for the case of internally generated types.
283   --  The result of the call is a new generated unique name of the form XyyyU
284   --  where X is Id_Char, yyy is a unique serial number, and U is either a
285   --  lower case s or b indicating if the current unit is a spec or a body.
286   --
287   --  The name is entered into the names table using Name_Enter rather than
288   --  Name_Find, because there can never be a need to locate the entry using
289   --  the Name_Find procedure later on. Names created by New_Internal_Name
290   --  are guaranteed to be consistent from one compilation to another (i.e.
291   --  if the identical unit is compiled with a semantically consistent set
292   --  of sources, the numbers will be consistent. This means that it is fine
293   --  to use these as public symbols.
294   --
295   --  Note: Nearly all uses of this function are via calls to Make_Temporary,
296   --  but there are just a few cases where it is called directly.
297
298   function New_Occurrence_Of
299     (Def_Id : Entity_Id;
300      Loc    : Source_Ptr) return Node_Id;
301   --  New_Occurrence_Of creates an N_Identifier node which is an occurrence
302   --  of the defining identifier which is passed as its argument. The Entity
303   --  and Etype of the result are set from the given defining identifier as
304   --  follows: Entity is simply a copy of Def_Id. Etype is a copy of Def_Id
305   --  for types, and a copy of the Etype of Def_Id for other entities.
306
307   function New_Suffixed_Name
308     (Related_Id : Name_Id;
309      Suffix     : String) return Name_Id;
310   --  This function is used to create special suffixed names used by the
311   --  debugger. Suffix is a string of upper case letters, used to construct
312   --  the required name. For instance, the special type used to record the
313   --  fixed-point small is called typ_SMALL where typ is the name of the
314   --  fixed-point type (as passed in Related_Id), and Suffix is "SMALL".
315
316   function OK_Convert_To (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
317   --  Like Convert_To, except that a conversion node is always generated, and
318   --  the Conversion_OK flag is set on this conversion node.
319
320   function Unchecked_Convert_To
321     (Typ  : Entity_Id;
322      Expr : Node_Id) return Node_Id;
323   --  Like Convert_To, but if a conversion is actually needed, constructs an
324   --  N_Unchecked_Type_Conversion node to do the required conversion.
325
326end Tbuild;
327