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 26with Types; use Types; 27package 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 183end Sem_Ch8; 184