1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                             S E M _ C H 1 2                              --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2018, 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 Inline; use Inline;
27with Types;  use Types;
28
29package Sem_Ch12 is
30   procedure Analyze_Generic_Package_Declaration        (N : Node_Id);
31   procedure Analyze_Generic_Subprogram_Declaration     (N : Node_Id);
32   procedure Analyze_Package_Instantiation              (N : Node_Id);
33   procedure Analyze_Procedure_Instantiation            (N : Node_Id);
34   procedure Analyze_Function_Instantiation             (N : Node_Id);
35   procedure Analyze_Formal_Object_Declaration          (N : Node_Id);
36   procedure Analyze_Formal_Type_Declaration            (N : Node_Id);
37   procedure Analyze_Formal_Subprogram_Declaration      (N : Node_Id);
38   procedure Analyze_Formal_Package_Declaration         (N : Node_Id);
39
40   procedure Add_Pending_Instantiation (Inst : Node_Id; Act_Decl : Node_Id);
41   --  Add an entry in the table of instance bodies that must be analyzed
42   --  when inlining requires its body or the body of a nested instance.
43
44   function Build_Function_Wrapper
45     (Formal_Subp : Entity_Id;
46      Actual_Subp : Entity_Id) return Node_Id;
47   --  In GNATprove mode, create a wrapper function for actuals that are
48   --  functions with any number of formal parameters, in order to propagate
49   --  their contract to the renaming declarations generated for them. This
50   --  is called after the renaming declaration created for the formal in the
51   --  instance has been analyzed, and the actual is known.
52
53   function Build_Operator_Wrapper
54     (Formal_Subp : Entity_Id;
55      Actual_Subp : Entity_Id) return Node_Id;
56   --  In GNATprove mode, create a wrapper function for actuals that are
57   --  operators, in order to propagate their contract to the renaming
58   --  declarations generated for them. The types are (the instances of)
59   --  the types of the formal subprogram.
60
61   procedure Start_Generic;
62   --  Must be invoked before starting to process a generic spec or body
63
64   procedure End_Generic;
65   --  Must be invoked just at the end of the end of the processing of a
66   --  generic spec or body.
67
68   procedure Check_Generic_Child_Unit
69     (Gen_Id           : Node_Id;
70      Parent_Installed : in out Boolean);
71   --  If the name of the generic unit in an instantiation or a renaming is a
72   --  selected component, then the prefix may be an instance and the selector
73   --  may designate a child unit. Retrieve the parent generic and search for
74   --  the child unit that must be declared within. Similarly, if this is the
75   --  name of a generic child unit within an instantiation of its own parent,
76   --  retrieve the parent generic. If the parent is installed as a result of
77   --  this call, then Parent_Installed is set True, otherwise Parent_Installed
78   --  is unchanged by the call.
79
80   function Copy_Generic_Node
81     (N             : Node_Id;
82      Parent_Id     : Node_Id;
83      Instantiating : Boolean) return Node_Id;
84   --  Copy the tree for a generic unit or its body. The unit is copied
85   --  repeatedly: once to produce a copy on which semantic analysis of
86   --  the generic is performed, and once for each instantiation. The tree
87   --  being copied is not semantically analyzed, except that references to
88   --  global entities are marked on terminal nodes. Note that this function
89   --  copies any aspect specifications from the input node N to the returned
90   --  node, as well as the setting of the Has_Aspects flag.
91
92   function Get_Instance_Of (A : Entity_Id) return Entity_Id;
93   --  Retrieve actual associated with given generic parameter.
94   --  If A is uninstantiated or not a generic parameter, return A.
95
96   function Get_Unit_Instantiation_Node (A : Entity_Id) return Node_Id;
97   --  Given the entity of a unit that is an instantiation, retrieve the
98   --  original instance node. This is used when loading the instantiations
99   --  of the ancestors of a child generic that is being instantiated.
100
101   procedure Instantiate_Package_Body
102     (Body_Info     : Pending_Body_Info;
103      Inlined_Body  : Boolean := False;
104      Body_Optional : Boolean := False);
105   --  Called after semantic analysis, to complete the instantiation of
106   --  package instances. The flag Inlined_Body is set if the body is
107   --  being instantiated on the fly for inlining purposes.
108   --
109   --  The flag Body_Optional indicates that the call is for an instance
110   --  that precedes the current instance in the same declarative part.
111   --  This call is needed when instantiating a nested generic whose body
112   --  is to be found in the body of an instance. Normally we instantiate
113   --  package bodies only when they appear in the main unit, or when their
114   --  contents are needed for a nested generic G. If unit U contains several
115   --  instances I1, I2, etc. and I2 contains a nested generic, then when U
116   --  appears in the context of some other unit P that contains an instance
117   --  of G, we compile the body of I2, but not that of I1. However, when we
118   --  compile U as the main unit, we compile both bodies. This will lead to
119   --  link-time errors if the compilation of I1 generates public symbols,
120   --  because those in I2 will receive different names in both cases. This
121   --  forces us to analyze the body of I1 even when U is not the main unit.
122   --  We don't want this additional mechanism to generate an error when the
123   --  body of the generic for I1 is not present, and this is the reason for
124   --  the presence of the flag Body_Optional, which is exchanged between the
125   --  current procedure and Load_Parent_Of_Generic.
126
127   procedure Instantiate_Subprogram_Body
128     (Body_Info     : Pending_Body_Info;
129      Body_Optional : Boolean := False);
130   --  Called after semantic analysis, to complete the instantiation of
131   --  function and procedure instances. The flag Body_Optional has the
132   --  same purpose as described for Instantiate_Package_Body.
133
134   function Need_Subprogram_Instance_Body
135     (N    : Node_Id;
136      Subp : Entity_Id) return Boolean;
137   --  If a subprogram instance is inlined, indicate that the body of it
138   --  must be created, to be used in inlined calls by the back-end. The
139   --  subprogram may be inlined because the generic itself carries the
140   --  pragma, or because a pragma appears for the instance in the scope.
141   --  of the instance.
142
143   procedure Save_Global_References (Templ : Node_Id);
144   --  Traverse the original generic unit, and capture all references to
145   --  entities that are defined outside of the generic in the analyzed tree
146   --  for the template. These references are copied into the original tree,
147   --  so that they appear automatically in every instantiation. A critical
148   --  invariant in this approach is that if an id in the generic resolves to
149   --  a local entity, the corresponding id in the instance will resolve to
150   --  the homologous entity in the instance, even though the enclosing context
151   --  for resolution is different, as long as the global references have been
152   --  captured as described here.
153
154   --  Because instantiations can be nested, the environment of the instance,
155   --  involving the actuals and other data-structures, must be saved and
156   --  restored in stack-like fashion. Front-end inlining also uses these
157   --  structures for the management of private/full views.
158
159   procedure Save_Global_References_In_Aspects (N : Node_Id);
160   --  Save all global references found within the expressions of all aspects
161   --  that appear on node N.
162
163   procedure Set_Copied_Sloc_For_Inlined_Body (N : Node_Id; E : Entity_Id);
164   --  This procedure is used when a subprogram body is inlined. This process
165   --  shares the same circuitry as the creation of an instantiated copy of
166   --  a generic template. The call to this procedure establishes a new source
167   --  file entry representing the inlined body as an instantiation, marked as
168   --  an inlined body (so that errout can distinguish cases for generating
169   --  error messages, otherwise the treatment is identical). In this call
170   --  N is the subprogram body and E is the defining identifier of the
171   --  subprogram in question. The resulting Sloc adjustment factor is
172   --  saved as part of the internal state of the Sem_Ch12 package for use
173   --  in subsequent calls to copy nodes.
174
175   procedure Set_Copied_Sloc_For_Inherited_Pragma
176     (N : Node_Id;
177      E : Entity_Id);
178   --  This procedure is used when a class-wide pre- or postcondition is
179   --  inherited. This process shares the same circuitry as the creation of
180   --  an instantiated copy of a generic template. The call to this procedure
181   --  establishes a new source file entry representing the inherited pragma
182   --  as an instantiation, marked as an inherited pragma (so that errout can
183   --  distinguish cases for generating error messages, otherwise the treatment
184   --  is identical). In this call, N is the subprogram declaration from
185   --  which the pragma is inherited and E is the defining identifier of
186   --  the overriding subprogram (when the subprogram is redefined) or the
187   --  defining identifier of the extension type (when the subprogram is
188   --  inherited). The resulting Sloc adjustment factor is saved as part of the
189   --  internal state of the Sem_Ch12 package for use in subsequent calls to
190   --  copy nodes.
191
192   procedure Adjust_Inherited_Pragma_Sloc (N : Node_Id);
193   --  This procedure is used when a class-wide pre- or postcondition
194   --  is inherited. It is called on each node of the pragma expression
195   --  to adjust its sloc. These call should be preceded by a call to
196   --  Set_Copied_Sloc_For_Inherited_Pragma that sets the required sloc
197   --  adjustment. This is done directly, instead of using Copy_Generic_Node
198   --  to copy nodes and adjust slocs, as Copy_Generic_Node expects a specific
199   --  structure to be in place, which is not the case for inherited pragmas.
200
201   procedure Save_Env
202     (Gen_Unit : Entity_Id;
203      Act_Unit : Entity_Id);
204   --  Because instantiations can be nested, the compiler maintains a stack
205   --  of environments that holds variables relevant to the current instance:
206   --  most importanty Instantiated_Parent, Exchanged_Views, Hidden_Entities,
207   --  and others (see full list in Instance_Env).
208
209   procedure Restore_Env;
210   --  After processing an instantiation, or aborting one because of semantic
211   --  errors, remove the current Instantiation_Env from Instantation_Envs.
212
213   procedure Initialize;
214   --  Initializes internal data structures
215
216   procedure Check_Private_View (N : Node_Id);
217   --  Check whether the type of a generic entity has a different view between
218   --  the point of generic analysis and the point of instantiation. If the
219   --  view has changed, then at the point of instantiation we restore the
220   --  correct view to perform semantic analysis of the instance, and reset
221   --  the current view after instantiation. The processing is driven by the
222   --  current private status of the type of the node, and Has_Private_View,
223   --  a flag that is set at the point of generic compilation. If view and
224   --  flag are inconsistent then the type is updated appropriately.
225   --
226   --  This subprogram is used in Check_Generic_Actuals and Copy_Generic_Node,
227   --  and is exported here for the purpose of front-end inlining (see Exp_Ch6.
228   --  Expand_Inlined_Call.Process_Formals).
229
230end Sem_Ch12;
231