------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ C H 8 -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2019, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING3. If not, go to -- -- http://www.gnu.org/licenses for a complete copy of the license. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with Types; use Types; package Sem_Ch8 is ----------------------------------- -- Handling extensions of System -- ----------------------------------- -- For targets that define a much larger System package than given in -- the RM, we use a child package containing additional declarations, -- which is loaded when needed, and whose entities are conceptually -- within System itself. The presence of this auxiliary package is -- controlled with the pragma Extend_System. The following variable -- holds the entity of the auxiliary package, to simplify the special -- visibility rules that apply to it. System_Aux_Id : Entity_Id := Empty; ----------------- -- Subprograms -- ----------------- procedure Analyze_Exception_Renaming (N : Node_Id); procedure Analyze_Expanded_Name (N : Node_Id); procedure Analyze_Generic_Function_Renaming (N : Node_Id); procedure Analyze_Generic_Package_Renaming (N : Node_Id); procedure Analyze_Generic_Procedure_Renaming (N : Node_Id); procedure Analyze_Object_Renaming (N : Node_Id); procedure Analyze_Package_Renaming (N : Node_Id); procedure Analyze_Subprogram_Renaming (N : Node_Id); procedure Analyze_Use_Package (N : Node_Id; Chain : Boolean := True); -- Analyze a use package clause and control (through the Chain parameter) -- whether to add N to the use clause chain for the name denoted within -- use clause N in case we are reanalyzing a use clause because of stack -- manipulation. procedure Analyze_Use_Type (N : Node_Id; Chain : Boolean := True); -- Similar to Analyze_Use_Package except the Chain parameter applies to the -- type within N's subtype mark Current_Use_Clause. procedure End_Scope; -- Called at end of scope. On exit from blocks and bodies (subprogram, -- package, task, and protected bodies), the name of the current scope -- must be removed from the scope stack, and the local entities must be -- removed from their homonym chains. On exit from record declarations, -- from package specifications, and from tasks and protected type -- specifications, more specialized procedures are invoked. procedure End_Use_Clauses (Clause : Node_Id); -- Invoked on scope exit, to undo the effect of local use clauses. Clause -- is the first use-clause of a scope being exited. This can be the current -- scope, or some enclosing scopes when building a clean environment to -- compile an instance body for inlining. procedure End_Use_Package (N : Node_Id); procedure End_Use_Type (N : Node_Id); -- Subsidiaries of End_Use_Clauses. Also called directly for use clauses -- appearing in context clauses. procedure Find_Direct_Name (N : Node_Id; Errors_OK : Boolean := True; Marker_OK : Boolean := True; Reference_OK : Boolean := True); -- Given a direct name (Identifier or Operator_Symbol), this routine scans -- the homonym chain for the name, searching for corresponding visible -- entities to find the referenced entity (or in the case of overloading, -- one candidate interpretation). On return, the Entity and Etype fields -- are set. In the non-overloaded case, these are the correct entries. -- In the overloaded case, the flag Is_Overloaded is set, Etype and Entity -- refer to an arbitrary element of the overloads set, and the appropriate -- entries have been added to the overloads table entry for the node. The -- overloading will be disambiguated during type resolution. -- -- Note, when this is called during semantic analysis in the overloaded -- case, the entity set will be the most recently declared homonym. In -- particular, the caller may follow the homonym chain checking for all -- entries in the current scope, and that will give all homonyms that are -- declared before the point of call in the current scope. This is useful -- for example in the processing for pragma Inline. -- -- Flag Errors_OK should be set when error diagnostics are desired. Flag -- Marker_OK should be set when a N_Variable_Reference_Marker needs to be -- generated for a SPARK object in order to detect elaboration issues. Flag -- Reference_OK should be set when N must generate a cross reference. procedure Find_Selected_Component (N : Node_Id); -- Resolve various cases of selected components, recognize expanded names procedure Find_Type (N : Node_Id); -- Perform name resolution, and verify that the name found is that of a -- type. On return the Entity and Etype fields of the node N are set -- appropriately. If it is an incomplete type whose full declaration has -- been seen, they are set to the entity in the full declaration. If it -- is an incomplete type associated with an interface visible through a -- limited-with clause, whose full declaration has been seen, they are -- set to the entity in the full declaration. Similarly, if the type is -- private, it has received a full declaration, and we are in the private -- part or body of the package, then the two fields are set to the entity -- of the full declaration as well. This procedure also has special -- processing for 'Class attribute references. function Has_Loop_In_Inner_Open_Scopes (S : Entity_Id) return Boolean; -- S is the entity of an open scope. This function determines if there is -- an inner scope of S which is a loop (i.e. it appears somewhere in the -- scope stack after S). function In_Open_Scopes (S : Entity_Id) return Boolean; -- S is the entity of a scope. This function determines if this scope is -- currently open (i.e. it appears somewhere in the scope stack). procedure Initialize; -- Initializes data structures used for visibility analysis. Must be -- called before analyzing each new main source program. procedure Install_Use_Clauses (Clause : Node_Id; Force_Installation : Boolean := False); -- Applies the use clauses appearing in a given declarative part, -- when the corresponding scope has been placed back on the scope -- stack after unstacking to compile a different context (subunit or -- parent of generic body). Force_Installation is used when called from -- Analyze_Subunit.Re_Install_Use_Clauses to insure that, after the -- analysis of the subunit, the parent's environment is again identical. procedure Mark_Use_Clauses (Id : Node_Or_Entity_Id); -- Mark a given entity or node Id's relevant use clauses as effective, -- including redundant ones and ones outside of the current scope. procedure Push_Scope (S : Entity_Id); -- Make new scope stack entry, pushing S, the entity for a scope onto the -- top of the scope table. The current setting of the scope suppress flags -- is saved for restoration on exit. procedure Pop_Scope; -- Remove top entry from scope stack, restoring the saved setting of the -- scope suppress flags. function Present_System_Aux (N : Node_Id := Empty) return Boolean; -- Return True if the auxiliary system file has been successfully loaded. -- Otherwise attempt to load it, using the name supplied by a previous -- Extend_System pragma, and report on the success of the load. If N is -- present, it is a selected component whose prefix is System, or else a -- with-clause on system. N is absent when the function is called to find -- the visibility of implicit operators. function Save_Scope_Stack (Handle_Use : Boolean := True) return Elist_Id; procedure Restore_Scope_Stack (List : Elist_Id; Handle_Use : Boolean := True); -- These two subprograms are called from Semantics, when a unit U1 is to -- be compiled in the course of the compilation of another unit U2. This -- happens whenever Rtsfind is called. U1, the unit retrieved by Rtsfind, -- must be compiled in its own context, and the current scope stack -- containing U2 and local scopes must be made unreachable. This is -- achieved using a call to Save_Scope_Stack. On return, the contents -- of the scope stack must be made accessible again with a call to -- Restore_Scope_Stack. -- -- The flag Handle_Use indicates whether local use clauses must be removed -- or installed. In the case of inlining of instance bodies, the visibility -- handling is done fully in Inline_Instance_Body, and use clauses are -- handled there. Save_Scope_Stack returns the list of entities which have -- been temporarily removed from visibility; that list must be passed to -- Restore_Scope_Stack to restore their visibility. procedure Set_Use (L : List_Id); -- Find use clauses that are declarative items in a package declaration -- and set the potentially use-visible flags of imported entities before -- analyzing the corresponding package body. procedure Update_Use_Clause_Chain; -- Called at the end of a declarative region to detect unused use type -- clauses and maintain the Current_Use_Clause for type entities. procedure ws; -- Debugging routine for use in gdb: dump all entities on scope stack procedure we (S : Entity_Id); -- Debugging routine for use in gdb: dump all entities in given scope end Sem_Ch8;