1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                              S E M _ C H 6                               --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2015, 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
26with Types; use Types;
27package Sem_Ch6 is
28
29   type Conformance_Type is
30     (Type_Conformant, Mode_Conformant, Subtype_Conformant, Fully_Conformant);
31   pragma Ordered (Conformance_Type);
32   --  Conformance type used in conformance checks between specs and bodies,
33   --  and for overriding. The literals match the RM definitions of the
34   --  corresponding terms. This is an ordered type, since each conformance
35   --  type is stronger than the ones preceding it.
36
37   procedure Analyze_Abstract_Subprogram_Declaration (N : Node_Id);
38   procedure Analyze_Expression_Function             (N : Node_Id);
39   procedure Analyze_Extended_Return_Statement       (N : Node_Id);
40   procedure Analyze_Function_Call                   (N : Node_Id);
41   procedure Analyze_Operator_Symbol                 (N : Node_Id);
42   procedure Analyze_Parameter_Association           (N : Node_Id);
43   procedure Analyze_Procedure_Call                  (N : Node_Id);
44   procedure Analyze_Simple_Return_Statement         (N : Node_Id);
45   procedure Analyze_Subprogram_Declaration          (N : Node_Id);
46   procedure Analyze_Subprogram_Body                 (N : Node_Id);
47
48   procedure Analyze_Subprogram_Body_Contract (Body_Id : Entity_Id);
49   --  Analyze all delayed aspects chained on the contract of subprogram body
50   --  Body_Id as if they appeared at the end of a declarative region. Aspects
51   --  in question are:
52   --    Contract_Cases   (stand alone body)
53   --    Depends          (stand alone body)
54   --    Global           (stand alone body)
55   --    Postcondition    (stand alone body)
56   --    Precondition     (stand alone body)
57   --    Refined_Depends
58   --    Refined_Global
59   --    Refined_Post
60   --    Test_Case        (stand alone body)
61
62   procedure Analyze_Subprogram_Contract (Subp_Id : Entity_Id);
63   --  Analyze all delayed aspects chained on the contract of subprogram
64   --  Subp_Id as if they appeared at the end of a declarative region. The
65   --  aspects in question are:
66   --    Contract_Cases
67   --    Depends
68   --    Global
69   --    Postcondition
70   --    Precondition
71   --    Test_Case
72
73   function Analyze_Subprogram_Specification (N : Node_Id) return Entity_Id;
74   --  Analyze subprogram specification in both subprogram declarations
75   --  and body declarations. Returns the defining entity for the
76   --  specification N.
77
78   procedure Check_Conventions (Typ : Entity_Id);
79   --  Ada 2005 (AI-430): Check that the conventions of all inherited and
80   --  overridden dispatching operations of type Typ are consistent with their
81   --  respective counterparts.
82
83   procedure Check_Delayed_Subprogram (Designator : Entity_Id);
84   --  Designator can be a E_Subprogram_Type, E_Procedure or E_Function. If a
85   --  type in its profile depends on a private type without a full
86   --  declaration, indicate that the subprogram or type is delayed.
87
88   procedure Check_Discriminant_Conformance
89     (N        : Node_Id;
90      Prev     : Entity_Id;
91      Prev_Loc : Node_Id);
92   --  Check that the discriminants of a full type N fully conform to the
93   --  discriminants of the corresponding partial view Prev. Prev_Loc indicates
94   --  the source location of the partial view, which may be different than
95   --  Prev in the case of private types.
96
97   procedure Check_Fully_Conformant
98     (New_Id  : Entity_Id;
99      Old_Id  : Entity_Id;
100      Err_Loc : Node_Id := Empty);
101   --  Check that two callable entities (subprograms, entries, literals)
102   --  are fully conformant, post error message if not (RM 6.3.1(17)) with
103   --  the flag being placed on the Err_Loc node if it is specified, and
104   --  on the appropriate component of the New_Id construct if not. Note:
105   --  when checking spec/body conformance, New_Id must be the body entity
106   --  and Old_Id is the spec entity (the code in the implementation relies
107   --  on this ordering, and in any case, this makes sense, since if flags
108   --  are to be placed on the construct, they clearly belong on the body.
109
110   procedure Check_Mode_Conformant
111     (New_Id   : Entity_Id;
112      Old_Id   : Entity_Id;
113      Err_Loc  : Node_Id := Empty;
114      Get_Inst : Boolean := False);
115   --  Check that two callable entities (subprograms, entries, literals)
116   --  are mode conformant, post error message if not (RM 6.3.1(15)) with
117   --  the flag being placed on the Err_Loc node if it is specified, and
118   --  on the appropriate component of the New_Id construct if not. The
119   --  argument Get_Inst is set to True when this is a check against a
120   --  formal access-to-subprogram type, indicating that mapping of types
121   --  is needed.
122
123   procedure Check_Overriding_Indicator
124     (Subp            : Entity_Id;
125      Overridden_Subp : Entity_Id;
126      Is_Primitive    : Boolean);
127   --  Verify the consistency of an overriding_indicator given for subprogram
128   --  declaration, body, renaming, or instantiation.  Overridden_Subp is set
129   --  if the scope where we are introducing the subprogram contains a
130   --  type-conformant subprogram that becomes hidden by the new subprogram.
131   --  Is_Primitive indicates whether the subprogram is primitive.
132
133   procedure Check_Subtype_Conformant
134     (New_Id                   : Entity_Id;
135      Old_Id                   : Entity_Id;
136      Err_Loc                  : Node_Id := Empty;
137      Skip_Controlling_Formals : Boolean := False;
138      Get_Inst                 : Boolean := False);
139   --  Check that two callable entities (subprograms, entries, literals)
140   --  are subtype conformant, post error message if not (RM 6.3.1(16)),
141   --  the flag being placed on the Err_Loc node if it is specified, and
142   --  on the appropriate component of the New_Id construct if not.
143   --  Skip_Controlling_Formals is True when checking the conformance of
144   --  a subprogram that implements an interface operation. In that case,
145   --  only the non-controlling formals can (and must) be examined. The
146   --  argument Get_Inst is set to True when this is a check against a
147   --  formal access-to-subprogram type, indicating that mapping of types
148   --  is needed.
149
150   procedure Check_Type_Conformant
151     (New_Id  : Entity_Id;
152      Old_Id  : Entity_Id;
153      Err_Loc : Node_Id := Empty);
154   --  Check that two callable entities (subprograms, entries, literals)
155   --  are type conformant, post error message if not (RM 6.3.1(14)) with
156   --  the flag being placed on the Err_Loc node if it is specified, and
157   --  on the appropriate component of the New_Id construct if not.
158
159   function Conforming_Types
160     (T1       : Entity_Id;
161      T2       : Entity_Id;
162      Ctype    : Conformance_Type;
163      Get_Inst : Boolean := False) return Boolean;
164   --  Check that the types of two formal parameters are conforming. In most
165   --  cases this is just a name comparison, but within an instance it involves
166   --  generic actual types, and in the presence of anonymous access types
167   --  it must examine the designated types. The argument Get_Inst is set to
168   --  True when this is a check against a formal access-to-subprogram type,
169   --  indicating that mapping of types is needed.
170
171   procedure Create_Extra_Formals (E : Entity_Id);
172   --  For each parameter of a subprogram or entry that requires an additional
173   --  formal (such as for access parameters and indefinite discriminated
174   --  parameters), creates the appropriate formal and attach it to its
175   --  associated parameter. Each extra formal will also be appended to
176   --  the end of Subp's parameter list (with each subsequent extra formal
177   --  being attached to the preceding extra formal).
178
179   function Find_Corresponding_Spec
180     (N          : Node_Id;
181      Post_Error : Boolean := True) return Entity_Id;
182   --  Use the subprogram specification in the body to retrieve the previous
183   --  subprogram declaration, if any.
184
185   function Fully_Conformant (New_Id, Old_Id : Entity_Id) return Boolean;
186   --  Determine whether two callable entities (subprograms, entries,
187   --  literals) are fully conformant (RM 6.3.1(17))
188
189   function Fully_Conformant_Expressions
190     (Given_E1 : Node_Id;
191      Given_E2 : Node_Id) return Boolean;
192   --  Determines if two (non-empty) expressions are fully conformant
193   --  as defined by (RM 6.3.1(18-21))
194
195   function Fully_Conformant_Discrete_Subtypes
196      (Given_S1 : Node_Id;
197       Given_S2 : Node_Id) return Boolean;
198   --  Determines if two subtype definitions are fully conformant. Used
199   --  for entry family conformance checks (RM 6.3.1 (24)).
200
201   procedure Install_Entity (E : Entity_Id);
202   --  Place a single entity on the visibility chain
203
204   procedure Install_Formals (Id : Entity_Id);
205   --  On entry to a subprogram body, make the formals visible. Note that
206   --  simply placing the subprogram on the scope stack is not sufficient:
207   --  the formals must become the current entities for their names. This
208   --  procedure is also used to get visibility to the formals when analyzing
209   --  preconditions and postconditions appearing in the spec.
210
211   function Is_Interface_Conformant
212     (Tagged_Type : Entity_Id;
213      Iface_Prim  : Entity_Id;
214      Prim        : Entity_Id) return Boolean;
215   --  Returns true if both primitives have a matching name (including support
216   --  for names of inherited private primitives --which have suffix 'P'), they
217   --  are type conformant, and Prim is defined in the scope of Tagged_Type.
218   --  Special management is done for functions returning interfaces.
219
220   procedure List_Inherited_Pre_Post_Aspects (E : Entity_Id);
221   --  E is the entity for a subprogram or generic subprogram spec. This call
222   --  lists all inherited Pre/Post aspects if List_Inherited_Pre_Post is True.
223
224   procedure May_Need_Actuals (Fun : Entity_Id);
225   --  Flag functions that can be called without parameters, i.e. those that
226   --  have no parameters, or those for which defaults exist for all parameters
227   --  Used for subprogram declarations and for access subprogram declarations,
228   --  where they apply to the anonymous designated type. On return the flag
229   --  Set_Needs_No_Actuals is set appropriately in Fun.
230
231   function Mode_Conformant (New_Id, Old_Id : Entity_Id) return Boolean;
232   --  Determine whether two callable entities (subprograms, entries,
233   --  literals) are mode conformant (RM 6.3.1(15))
234
235   procedure New_Overloaded_Entity
236     (S            : Entity_Id;
237      Derived_Type : Entity_Id := Empty);
238   --  Process new overloaded entity. Overloaded entities are created by
239   --  enumeration type declarations, subprogram specifications, entry
240   --  declarations, and (implicitly) by type derivations. If Derived_Type
241   --  is non-empty then this is a subprogram derived for that type.
242
243   procedure Process_Formals (T : List_Id; Related_Nod : Node_Id);
244   --  Enter the formals in the scope of the subprogram or entry, and
245   --  analyze default expressions if any. The implicit types created for
246   --  access parameter are attached to the Related_Nod which comes from the
247   --  context.
248
249   procedure Reference_Body_Formals (Spec : Entity_Id; Bod : Entity_Id);
250   --  If there is a separate spec for a subprogram or generic subprogram, the
251   --  formals of the body are treated as references to the corresponding
252   --  formals of the spec. This reference does not count as an actual use of
253   --  the formal, in order to diagnose formals that are unused in the body.
254   --  This procedure is also used in renaming_as_body declarations, where
255   --  the formals of the specification must be treated as body formals that
256   --  correspond to the previous subprogram declaration, and not as new
257   --  entities with their defining entry in the cross-reference information.
258
259   procedure Set_Actual_Subtypes (N : Node_Id; Subp : Entity_Id);
260   --  If the formals of a subprogram are unconstrained, build a subtype
261   --  declaration that uses the bounds or discriminants of the actual to
262   --  construct an actual subtype for them. This is an optimization that
263   --  is done only in some cases where the actual subtype cannot change
264   --  during execution of the subprogram. By setting the actual subtype
265   --  once, we avoid recomputing it unnecessarily.
266
267   procedure Set_Formal_Mode (Formal_Id : Entity_Id);
268   --  Set proper Ekind to reflect formal mode (in, out, in out)
269
270   function Subtype_Conformant
271     (New_Id                   : Entity_Id;
272      Old_Id                   : Entity_Id;
273      Skip_Controlling_Formals : Boolean := False) return Boolean;
274   --  Determine whether two callable entities (subprograms, entries, literals)
275   --  are subtype conformant (RM 6.3.1(16)). Skip_Controlling_Formals is True
276   --  when checking the conformance of a subprogram that implements an
277   --  interface operation. In that case, only the non-controlling formals
278   --  can (and must) be examined.
279
280   function Type_Conformant
281     (New_Id                   : Entity_Id;
282      Old_Id                   : Entity_Id;
283      Skip_Controlling_Formals : Boolean := False) return Boolean;
284   --  Determine whether two callable entities (subprograms, entries, literals)
285   --  are type conformant (RM 6.3.1(14)). Skip_Controlling_Formals is True
286   --  when checking the conformance of a subprogram that implements an
287   --  interface operation. In that case, only the non-controlling formals
288   --  can (and must) be examined.
289
290   procedure Valid_Operator_Definition (Designator : Entity_Id);
291   --  Verify that an operator definition has the proper number of formals
292
293end Sem_Ch6;
294