1------------------------------------------------------------------------------ 2-- -- 3-- GNAT COMPILER COMPONENTS -- 4-- -- 5-- S E M _ C H 8 -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2019, 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 56 procedure Analyze_Use_Package (N : Node_Id; Chain : Boolean := True); 57 -- Analyze a use package clause and control (through the Chain parameter) 58 -- whether to add N to the use clause chain for the name denoted within 59 -- use clause N in case we are reanalyzing a use clause because of stack 60 -- manipulation. 61 62 procedure Analyze_Use_Type (N : Node_Id; Chain : Boolean := True); 63 -- Similar to Analyze_Use_Package except the Chain parameter applies to the 64 -- type within N's subtype mark Current_Use_Clause. 65 66 procedure End_Scope; 67 -- Called at end of scope. On exit from blocks and bodies (subprogram, 68 -- package, task, and protected bodies), the name of the current scope 69 -- must be removed from the scope stack, and the local entities must be 70 -- removed from their homonym chains. On exit from record declarations, 71 -- from package specifications, and from tasks and protected type 72 -- specifications, more specialized procedures are invoked. 73 74 procedure End_Use_Clauses (Clause : Node_Id); 75 -- Invoked on scope exit, to undo the effect of local use clauses. Clause 76 -- is the first use-clause of a scope being exited. This can be the current 77 -- scope, or some enclosing scopes when building a clean environment to 78 -- compile an instance body for inlining. 79 80 procedure End_Use_Package (N : Node_Id); 81 procedure End_Use_Type (N : Node_Id); 82 -- Subsidiaries of End_Use_Clauses. Also called directly for use clauses 83 -- appearing in context clauses. 84 85 procedure Find_Direct_Name 86 (N : Node_Id; 87 Errors_OK : Boolean := True; 88 Marker_OK : Boolean := True; 89 Reference_OK : Boolean := True); 90 -- Given a direct name (Identifier or Operator_Symbol), this routine scans 91 -- the homonym chain for the name, searching for corresponding visible 92 -- entities to find the referenced entity (or in the case of overloading, 93 -- one candidate interpretation). On return, the Entity and Etype fields 94 -- are set. In the non-overloaded case, these are the correct entries. 95 -- In the overloaded case, the flag Is_Overloaded is set, Etype and Entity 96 -- refer to an arbitrary element of the overloads set, and the appropriate 97 -- entries have been added to the overloads table entry for the node. The 98 -- overloading will be disambiguated during type resolution. 99 -- 100 -- Note, when this is called during semantic analysis in the overloaded 101 -- case, the entity set will be the most recently declared homonym. In 102 -- particular, the caller may follow the homonym chain checking for all 103 -- entries in the current scope, and that will give all homonyms that are 104 -- declared before the point of call in the current scope. This is useful 105 -- for example in the processing for pragma Inline. 106 -- 107 -- Flag Errors_OK should be set when error diagnostics are desired. Flag 108 -- Marker_OK should be set when a N_Variable_Reference_Marker needs to be 109 -- generated for a SPARK object in order to detect elaboration issues. Flag 110 -- Reference_OK should be set when N must generate a cross reference. 111 112 procedure Find_Selected_Component (N : Node_Id); 113 -- Resolve various cases of selected components, recognize expanded names 114 115 procedure Find_Type (N : Node_Id); 116 -- Perform name resolution, and verify that the name found is that of a 117 -- type. On return the Entity and Etype fields of the node N are set 118 -- appropriately. If it is an incomplete type whose full declaration has 119 -- been seen, they are set to the entity in the full declaration. If it 120 -- is an incomplete type associated with an interface visible through a 121 -- limited-with clause, whose full declaration has been seen, they are 122 -- set to the entity in the full declaration. Similarly, if the type is 123 -- private, it has received a full declaration, and we are in the private 124 -- part or body of the package, then the two fields are set to the entity 125 -- of the full declaration as well. This procedure also has special 126 -- processing for 'Class attribute references. 127 128 function Has_Loop_In_Inner_Open_Scopes (S : Entity_Id) return Boolean; 129 -- S is the entity of an open scope. This function determines if there is 130 -- an inner scope of S which is a loop (i.e. it appears somewhere in the 131 -- scope stack after S). 132 133 function In_Open_Scopes (S : Entity_Id) return Boolean; 134 -- S is the entity of a scope. This function determines if this scope is 135 -- currently open (i.e. it appears somewhere in the scope stack). 136 137 procedure Initialize; 138 -- Initializes data structures used for visibility analysis. Must be 139 -- called before analyzing each new main source program. 140 141 procedure Install_Use_Clauses 142 (Clause : Node_Id; 143 Force_Installation : Boolean := False); 144 -- Applies the use clauses appearing in a given declarative part, 145 -- when the corresponding scope has been placed back on the scope 146 -- stack after unstacking to compile a different context (subunit or 147 -- parent of generic body). Force_Installation is used when called from 148 -- Analyze_Subunit.Re_Install_Use_Clauses to insure that, after the 149 -- analysis of the subunit, the parent's environment is again identical. 150 151 procedure Mark_Use_Clauses (Id : Node_Or_Entity_Id); 152 -- Mark a given entity or node Id's relevant use clauses as effective, 153 -- including redundant ones and ones outside of the current scope. 154 155 procedure Push_Scope (S : Entity_Id); 156 -- Make new scope stack entry, pushing S, the entity for a scope onto the 157 -- top of the scope table. The current setting of the scope suppress flags 158 -- is saved for restoration on exit. 159 160 procedure Pop_Scope; 161 -- Remove top entry from scope stack, restoring the saved setting of the 162 -- scope suppress flags. 163 164 function Present_System_Aux (N : Node_Id := Empty) return Boolean; 165 -- Return True if the auxiliary system file has been successfully loaded. 166 -- Otherwise attempt to load it, using the name supplied by a previous 167 -- Extend_System pragma, and report on the success of the load. If N is 168 -- present, it is a selected component whose prefix is System, or else a 169 -- with-clause on system. N is absent when the function is called to find 170 -- the visibility of implicit operators. 171 172 function Save_Scope_Stack 173 (Handle_Use : Boolean := True) return Elist_Id; 174 procedure Restore_Scope_Stack 175 (List : Elist_Id; 176 Handle_Use : Boolean := True); 177 -- These two subprograms are called from Semantics, when a unit U1 is to 178 -- be compiled in the course of the compilation of another unit U2. This 179 -- happens whenever Rtsfind is called. U1, the unit retrieved by Rtsfind, 180 -- must be compiled in its own context, and the current scope stack 181 -- containing U2 and local scopes must be made unreachable. This is 182 -- achieved using a call to Save_Scope_Stack. On return, the contents 183 -- of the scope stack must be made accessible again with a call to 184 -- Restore_Scope_Stack. 185 -- 186 -- The flag Handle_Use indicates whether local use clauses must be removed 187 -- or installed. In the case of inlining of instance bodies, the visibility 188 -- handling is done fully in Inline_Instance_Body, and use clauses are 189 -- handled there. Save_Scope_Stack returns the list of entities which have 190 -- been temporarily removed from visibility; that list must be passed to 191 -- Restore_Scope_Stack to restore their visibility. 192 193 procedure Set_Use (L : List_Id); 194 -- Find use clauses that are declarative items in a package declaration 195 -- and set the potentially use-visible flags of imported entities before 196 -- analyzing the corresponding package body. 197 198 procedure Update_Use_Clause_Chain; 199 -- Called at the end of a declarative region to detect unused use type 200 -- clauses and maintain the Current_Use_Clause for type entities. 201 202 procedure ws; 203 -- Debugging routine for use in gdb: dump all entities on scope stack 204 205 procedure we (S : Entity_Id); 206 -- Debugging routine for use in gdb: dump all entities in given scope 207 208end Sem_Ch8; 209