File : sem_ch12.ads
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) 1992-2016, 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 with Inline; use Inline;
27 with Types; use Types;
28
29 package 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_Package_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
230 end Sem_Ch12;