File : sem_ch8.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S E M _ C H 8 --
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 with Types; use Types;
27 package Sem_Ch8 is
28
29 -----------------------------------
30 -- Handling extensions of System --
31 -----------------------------------
32
33 -- For targets that define a much larger System package than given in
34 -- the RM, we use a child package containing additional declarations,
35 -- which is loaded when needed, and whose entities are conceptually
36 -- within System itself. The presence of this auxiliary package is
37 -- controlled with the pragma Extend_System. The following variable
38 -- holds the entity of the auxiliary package, to simplify the special
39 -- visibility rules that apply to it.
40
41 System_Aux_Id : Entity_Id := Empty;
42
43 -----------------
44 -- Subprograms --
45 -----------------
46
47 procedure Analyze_Exception_Renaming (N : Node_Id);
48 procedure Analyze_Expanded_Name (N : Node_Id);
49 procedure Analyze_Generic_Function_Renaming (N : Node_Id);
50 procedure Analyze_Generic_Package_Renaming (N : Node_Id);
51 procedure Analyze_Generic_Procedure_Renaming (N : Node_Id);
52 procedure Analyze_Object_Renaming (N : Node_Id);
53 procedure Analyze_Package_Renaming (N : Node_Id);
54 procedure Analyze_Subprogram_Renaming (N : Node_Id);
55 procedure Analyze_Use_Package (N : Node_Id);
56 procedure Analyze_Use_Type (N : Node_Id);
57
58 procedure End_Scope;
59 -- Called at end of scope. On exit from blocks and bodies (subprogram,
60 -- package, task, and protected bodies), the name of the current scope
61 -- must be removed from the scope stack, and the local entities must be
62 -- removed from their homonym chains. On exit from record declarations,
63 -- from package specifications, and from tasks and protected type
64 -- specifications, more specialized procedures are invoked.
65
66 procedure End_Use_Clauses (Clause : Node_Id);
67 -- Invoked on scope exit, to undo the effect of local use clauses. Clause
68 -- is the first use-clause of a scope being exited. This can be the current
69 -- scope, or some enclosing scopes when building a clean environment to
70 -- compile an instance body for inlining.
71
72 procedure End_Use_Package (N : Node_Id);
73 procedure End_Use_Type (N : Node_Id);
74 -- Subsidiaries of End_Use_Clauses. Also called directly for use clauses
75 -- appearing in context clauses.
76
77 procedure Find_Direct_Name (N : Node_Id);
78 -- Given a direct name (Identifier or Operator_Symbol), this routine scans
79 -- the homonym chain for the name, searching for corresponding visible
80 -- entities to find the referenced entity (or in the case of overloading,
81 -- one candidate interpretation). On return, the Entity and Etype fields
82 -- are set. In the non-overloaded case, these are the correct entries.
83 -- In the overloaded case, the flag Is_Overloaded is set, Etype and Entity
84 -- refer to an arbitrary element of the overloads set, and the appropriate
85 -- entries have been added to the overloads table entry for the node. The
86 -- overloading will be disambiguated during type resolution.
87 --
88 -- Note, when this is called during semantic analysis in the overloaded
89 -- case, the entity set will be the most recently declared homonym. In
90 -- particular, the caller may follow the homonym chain checking for all
91 -- entries in the current scope, and that will give all homonyms that are
92 -- declared before the point of call in the current scope. This is useful
93 -- for example in the processing for pragma Inline.
94
95 procedure Find_Selected_Component (N : Node_Id);
96 -- Resolve various cases of selected components, recognize expanded names
97
98 procedure Find_Type (N : Node_Id);
99 -- Perform name resolution, and verify that the name found is that of a
100 -- type. On return the Entity and Etype fields of the node N are set
101 -- appropriately. If it is an incomplete type whose full declaration has
102 -- been seen, they are set to the entity in the full declaration. If it
103 -- is an incomplete type associated with an interface visible through a
104 -- limited-with clause, whose full declaration has been seen, they are
105 -- set to the entity in the full declaration. Similarly, if the type is
106 -- private, it has received a full declaration, and we are in the private
107 -- part or body of the package, then the two fields are set to the entity
108 -- of the full declaration as well. This procedure also has special
109 -- processing for 'Class attribute references.
110
111 function Has_Loop_In_Inner_Open_Scopes (S : Entity_Id) return Boolean;
112 -- S is the entity of an open scope. This function determines if there is
113 -- an inner scope of S which is a loop (i.e. it appears somewhere in the
114 -- scope stack after S).
115
116 function In_Open_Scopes (S : Entity_Id) return Boolean;
117 -- S is the entity of a scope. This function determines if this scope is
118 -- currently open (i.e. it appears somewhere in the scope stack).
119
120 procedure Initialize;
121 -- Initializes data structures used for visibility analysis. Must be
122 -- called before analyzing each new main source program.
123
124 procedure Install_Use_Clauses
125 (Clause : Node_Id;
126 Force_Installation : Boolean := False);
127 -- Applies the use clauses appearing in a given declarative part,
128 -- when the corresponding scope has been placed back on the scope
129 -- stack after unstacking to compile a different context (subunit or
130 -- parent of generic body). Force_Installation is used when called from
131 -- Analyze_Subunit.Re_Install_Use_Clauses to insure that, after the
132 -- analysis of the subunit, the parent's environment is again identical.
133
134 procedure Push_Scope (S : Entity_Id);
135 -- Make new scope stack entry, pushing S, the entity for a scope onto the
136 -- top of the scope table. The current setting of the scope suppress flags
137 -- is saved for restoration on exit.
138
139 procedure Pop_Scope;
140 -- Remove top entry from scope stack, restoring the saved setting of the
141 -- scope suppress flags.
142
143 function Present_System_Aux (N : Node_Id := Empty) return Boolean;
144 -- Return True if the auxiliary system file has been successfully loaded.
145 -- Otherwise attempt to load it, using the name supplied by a previous
146 -- Extend_System pragma, and report on the success of the load. If N is
147 -- present, it is a selected component whose prefix is System, or else a
148 -- with-clause on system. N is absent when the function is called to find
149 -- the visibility of implicit operators.
150
151 function Save_Scope_Stack
152 (Handle_Use : Boolean := True) return Elist_Id;
153 procedure Restore_Scope_Stack
154 (List : Elist_Id;
155 Handle_Use : Boolean := True);
156 -- These two subprograms are called from Semantics, when a unit U1 is to
157 -- be compiled in the course of the compilation of another unit U2. This
158 -- happens whenever Rtsfind is called. U1, the unit retrieved by Rtsfind,
159 -- must be compiled in its own context, and the current scope stack
160 -- containing U2 and local scopes must be made unreachable. This is
161 -- achieved using a call to Save_Scope_Stack. On return, the contents
162 -- of the scope stack must be made accessible again with a call to
163 -- Restore_Scope_Stack.
164 --
165 -- The flag Handle_Use indicates whether local use clauses must be removed
166 -- or installed. In the case of inlining of instance bodies, the visibility
167 -- handling is done fully in Inline_Instance_Body, and use clauses are
168 -- handled there. Save_Scope_Stack returns the list of entities which have
169 -- been temporarily removed from visibility; that list must be passed to
170 -- Restore_Scope_Stack to restore their visibility.
171
172 procedure Set_Use (L : List_Id);
173 -- Find use clauses that are declarative items in a package declaration
174 -- and set the potentially use-visible flags of imported entities before
175 -- analyzing the corresponding package body.
176
177 procedure ws;
178 -- Debugging routine for use in gdb: dump all entities on scope stack
179
180 procedure we (S : Entity_Id);
181 -- Debugging routine for use in gdb: dump all entities in given scope
182
183 end Sem_Ch8;