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diff --git a/gcc/ada/sem_ch10.adb b/gcc/ada/sem_ch10.adb new file mode 100644 index 00000000000..2bbe0a50081 --- /dev/null +++ b/gcc/ada/sem_ch10.adb @@ -0,0 +1,3072 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ C H 1 0 -- +-- -- +-- B o d y -- +-- -- +-- $Revision: 1.402 $ +-- -- +-- Copyright (C) 1992-2001 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 2, 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 COPYING. If not, write -- +-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- +-- MA 02111-1307, USA. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +with Atree; use Atree; +with Debug; use Debug; +with Einfo; use Einfo; +with Errout; use Errout; +with Exp_Util; use Exp_Util; +with Fname; use Fname; +with Fname.UF; use Fname.UF; +with Freeze; use Freeze; +with Impunit; use Impunit; +with Inline; use Inline; +with Lib; use Lib; +with Lib.Load; use Lib.Load; +with Lib.Xref; use Lib.Xref; +with Namet; use Namet; +with Nlists; use Nlists; +with Nmake; use Nmake; +with Opt; use Opt; +with Output; use Output; +with Restrict; use Restrict; +with Sem; use Sem; +with Sem_Ch6; use Sem_Ch6; +with Sem_Ch7; use Sem_Ch7; +with Sem_Ch8; use Sem_Ch8; +with Sem_Dist; use Sem_Dist; +with Sem_Prag; use Sem_Prag; +with Sem_Util; use Sem_Util; +with Sem_Warn; use Sem_Warn; +with Stand; use Stand; +with Sinfo; use Sinfo; +with Sinfo.CN; use Sinfo.CN; +with Sinput; use Sinput; +with Snames; use Snames; +with Style; use Style; +with Tbuild; use Tbuild; +with Ttypes; use Ttypes; +with Uname; use Uname; + +package body Sem_Ch10 is + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Analyze_Context (N : Node_Id); + -- Analyzes items in the context clause of compilation unit + + procedure Check_With_Type_Clauses (N : Node_Id); + -- If N is a body, verify that any with_type clauses on the spec, or + -- on the spec of any parent, have a matching with_clause. + + procedure Check_Private_Child_Unit (N : Node_Id); + -- If a with_clause mentions a private child unit, the compilation + -- unit must be a member of the same family, as described in 10.1.2 (8). + + procedure Check_Stub_Level (N : Node_Id); + -- Verify that a stub is declared immediately within a compilation unit, + -- and not in an inner frame. + + procedure Expand_With_Clause (Nam : Node_Id; N : Node_Id); + -- When a child unit appears in a context clause, the implicit withs on + -- parents are made explicit, and with clauses are inserted in the context + -- clause before the one for the child. If a parent in the with_clause + -- is a renaming, the implicit with_clause is on the renaming whose name + -- is mentioned in the with_clause, and not on the package it renames. + -- N is the compilation unit whose list of context items receives the + -- implicit with_clauses. + + procedure Implicit_With_On_Parent (Child_Unit : Node_Id; N : Node_Id); + -- If the main unit is a child unit, implicit withs are also added for + -- all its ancestors. + + procedure Install_Context_Clauses (N : Node_Id); + -- Subsidiary to previous one. Process only with_ and use_clauses for + -- current unit and its library unit if any. + + procedure Install_Withed_Unit (With_Clause : Node_Id); + -- If the unit is not a child unit, make unit immediately visible. + -- The caller ensures that the unit is not already currently installed. + + procedure Install_Parents (Lib_Unit : Node_Id; Is_Private : Boolean); + -- This procedure establishes the context for the compilation of a child + -- unit. If Lib_Unit is a child library spec then the context of the parent + -- is installed, and the parent itself made immediately visible, so that + -- the child unit is processed in the declarative region of the parent. + -- Install_Parents makes a recursive call to itself to ensure that all + -- parents are loaded in the nested case. If Lib_Unit is a library body, + -- the only effect of Install_Parents is to install the private decls of + -- the parents, because the visible parent declarations will have been + -- installed as part of the context of the corresponding spec. + + procedure Install_Siblings (U_Name : Entity_Id; N : Node_Id); + -- In the compilation of a child unit, a child of any of the ancestor + -- units is directly visible if it is visible, because the parent is in + -- an enclosing scope. Iterate over context to find child units of U_Name + -- or of some ancestor of it. + + function Is_Child_Spec (Lib_Unit : Node_Id) return Boolean; + -- Lib_Unit is a library unit which may be a spec or a body. Is_Child_Spec + -- returns True if Lib_Unit is a library spec which is a child spec, i.e. + -- a library spec that has a parent. If the call to Is_Child_Spec returns + -- True, then Parent_Spec (Lib_Unit) is non-Empty and points to the + -- compilation unit for the parent spec. + -- + -- Lib_Unit can also be a subprogram body that acts as its own spec. If + -- the Parent_Spec is non-empty, this is also a child unit. + + procedure Remove_With_Type_Clause (Name : Node_Id); + -- Remove imported type and its enclosing package from visibility, and + -- remove attributes of imported type so they don't interfere with its + -- analysis (should it appear otherwise in the context). + + procedure Remove_Context_Clauses (N : Node_Id); + -- Subsidiary of previous one. Remove use_ and with_clauses. + + procedure Remove_Parents (Lib_Unit : Node_Id); + -- Remove_Parents checks if Lib_Unit is a child spec. If so then the parent + -- contexts established by the corresponding call to Install_Parents are + -- removed. Remove_Parents contains a recursive call to itself to ensure + -- that all parents are removed in the nested case. + + procedure Remove_Unit_From_Visibility (Unit_Name : Entity_Id); + -- Reset all visibility flags on unit after compiling it, either as a + -- main unit or as a unit in the context. + + procedure Analyze_Proper_Body (N : Node_Id; Nam : Entity_Id); + -- Common processing for all stubs (subprograms, tasks, packages, and + -- protected cases). N is the stub to be analyzed. Once the subunit + -- name is established, load and analyze. Nam is the non-overloadable + -- entity for which the proper body provides a completion. Subprogram + -- stubs are handled differently because they can be declarations. + + ------------------------------ + -- Analyze_Compilation_Unit -- + ------------------------------ + + procedure Analyze_Compilation_Unit (N : Node_Id) is + Unit_Node : constant Node_Id := Unit (N); + Lib_Unit : Node_Id := Library_Unit (N); + Spec_Id : Node_Id; + Main_Cunit : constant Node_Id := Cunit (Main_Unit); + Par_Spec_Name : Unit_Name_Type; + Unum : Unit_Number_Type; + + procedure Generate_Parent_References (N : Node_Id; P_Id : Entity_Id); + -- Generate cross-reference information for the parents of child units. + -- N is a defining_program_unit_name, and P_Id is the immediate parent. + + -------------------------------- + -- Generate_Parent_References -- + -------------------------------- + + procedure Generate_Parent_References (N : Node_Id; P_Id : Entity_Id) is + Pref : Node_Id; + P_Name : Entity_Id := P_Id; + + begin + Pref := Name (Parent (Defining_Entity (N))); + + if Nkind (Pref) = N_Expanded_Name then + + -- Done already, if the unit has been compiled indirectly as + -- part of the closure of its context because of inlining. + + return; + end if; + + while Nkind (Pref) = N_Selected_Component loop + Change_Selected_Component_To_Expanded_Name (Pref); + Set_Entity (Pref, P_Name); + Set_Etype (Pref, Etype (P_Name)); + Generate_Reference (P_Name, Pref, 'r'); + Pref := Prefix (Pref); + P_Name := Scope (P_Name); + end loop; + + -- The guard here on P_Name is to handle the error condition where + -- the parent unit is missing because the file was not found. + + if Present (P_Name) then + Set_Entity (Pref, P_Name); + Set_Etype (Pref, Etype (P_Name)); + Generate_Reference (P_Name, Pref, 'r'); + Style.Check_Identifier (Pref, P_Name); + end if; + end Generate_Parent_References; + + -- Start of processing for Analyze_Compilation_Unit + + begin + Process_Compilation_Unit_Pragmas (N); + + -- If the unit is a subunit whose parent has not been analyzed (which + -- indicates that the main unit is a subunit, either the current one or + -- one of its descendents) then the subunit is compiled as part of the + -- analysis of the parent, which we proceed to do. Basically this gets + -- handled from the top down and we don't want to do anything at this + -- level (i.e. this subunit will be handled on the way down from the + -- parent), so at this level we immediately return. If the subunit + -- ends up not analyzed, it means that the parent did not contain a + -- stub for it, or that there errors were dectected in some ancestor. + + if Nkind (Unit_Node) = N_Subunit + and then not Analyzed (Lib_Unit) + then + Semantics (Lib_Unit); + + if not Analyzed (Proper_Body (Unit_Node)) then + if Errors_Detected > 0 then + Error_Msg_N ("subunit not analyzed (errors in parent unit)", N); + else + Error_Msg_N ("missing stub for subunit", N); + end if; + end if; + + return; + end if; + + -- Analyze context (this will call Sem recursively for with'ed units) + + Analyze_Context (N); + + -- If the unit is a package body, the spec is already loaded and must + -- be analyzed first, before we analyze the body. + + if Nkind (Unit_Node) = N_Package_Body then + + -- If no Lib_Unit, then there was a serious previous error, so + -- just ignore the entire analysis effort + + if No (Lib_Unit) then + return; + + else + Semantics (Lib_Unit); + Check_Unused_Withs (Get_Cunit_Unit_Number (Lib_Unit)); + + -- Verify that the library unit is a package declaration. + + if Nkind (Unit (Lib_Unit)) /= N_Package_Declaration + and then + Nkind (Unit (Lib_Unit)) /= N_Generic_Package_Declaration + then + Error_Msg_N + ("no legal package declaration for package body", N); + return; + + -- Otherwise, the entity in the declaration is visible. Update + -- the version to reflect dependence of this body on the spec. + + else + Spec_Id := Defining_Entity (Unit (Lib_Unit)); + Set_Is_Immediately_Visible (Spec_Id, True); + Version_Update (N, Lib_Unit); + + if Nkind (Defining_Unit_Name (Unit_Node)) + = N_Defining_Program_Unit_Name + then + Generate_Parent_References (Unit_Node, Scope (Spec_Id)); + end if; + end if; + end if; + + -- If the unit is a subprogram body, then we similarly need to analyze + -- its spec. However, things are a little simpler in this case, because + -- here, this analysis is done only for error checking and consistency + -- purposes, so there's nothing else to be done. + + elsif Nkind (Unit_Node) = N_Subprogram_Body then + if Acts_As_Spec (N) then + + -- If the subprogram body is a child unit, we must create a + -- declaration for it, in order to properly load the parent(s). + -- After this, the original unit does not acts as a spec, because + -- there is an explicit one. If this unit appears in a context + -- clause, then an implicit with on the parent will be added when + -- installing the context. If this is the main unit, there is no + -- Unit_Table entry for the declaration, (It has the unit number + -- of the main unit) and code generation is unaffected. + + Unum := Get_Cunit_Unit_Number (N); + Par_Spec_Name := Get_Parent_Spec_Name (Unit_Name (Unum)); + + if Par_Spec_Name /= No_Name then + Unum := + Load_Unit + (Load_Name => Par_Spec_Name, + Required => True, + Subunit => False, + Error_Node => N); + + if Unum /= No_Unit then + + -- Build subprogram declaration and attach parent unit to it + -- This subprogram declaration does not come from source! + + declare + Loc : constant Source_Ptr := Sloc (N); + SCS : constant Boolean := + Get_Comes_From_Source_Default; + + begin + Set_Comes_From_Source_Default (False); + Lib_Unit := + Make_Compilation_Unit (Loc, + Context_Items => New_Copy_List (Context_Items (N)), + Unit => + Make_Subprogram_Declaration (Sloc (N), + Specification => + Copy_Separate_Tree + (Specification (Unit_Node))), + Aux_Decls_Node => + Make_Compilation_Unit_Aux (Loc)); + + Set_Library_Unit (N, Lib_Unit); + Set_Parent_Spec (Unit (Lib_Unit), Cunit (Unum)); + Semantics (Lib_Unit); + Set_Acts_As_Spec (N, False); + Set_Comes_From_Source_Default (SCS); + end; + end if; + end if; + + -- Here for subprogram with separate declaration + + else + Semantics (Lib_Unit); + Check_Unused_Withs (Get_Cunit_Unit_Number (Lib_Unit)); + Version_Update (N, Lib_Unit); + end if; + + if Nkind (Defining_Unit_Name (Specification (Unit_Node))) = + N_Defining_Program_Unit_Name + then + Generate_Parent_References ( + Specification (Unit_Node), + Scope (Defining_Entity (Unit (Lib_Unit)))); + end if; + end if; + + -- If it is a child unit, the parent must be elaborated first + -- and we update version, since we are dependent on our parent. + + if Is_Child_Spec (Unit_Node) then + + -- The analysis of the parent is done with style checks off + + declare + Save_Style_Check : constant Boolean := Opt.Style_Check; + Save_C_Restrict : constant Save_Compilation_Unit_Restrictions := + Compilation_Unit_Restrictions_Save; + + begin + if not GNAT_Mode then + Style_Check := False; + end if; + + Semantics (Parent_Spec (Unit_Node)); + Version_Update (N, Parent_Spec (Unit_Node)); + Style_Check := Save_Style_Check; + Compilation_Unit_Restrictions_Restore (Save_C_Restrict); + end; + end if; + + -- With the analysis done, install the context. Note that we can't + -- install the context from the with clauses as we analyze them, + -- because each with clause must be analyzed in a clean visibility + -- context, so we have to wait and install them all at once. + + Install_Context (N); + + if Is_Child_Spec (Unit_Node) then + + -- Set the entities of all parents in the program_unit_name. + + Generate_Parent_References ( + Unit_Node, Defining_Entity (Unit (Parent_Spec (Unit_Node)))); + end if; + + -- All components of the context: with-clauses, library unit, ancestors + -- if any, (and their context) are analyzed and installed. Now analyze + -- the unit itself, which is either a package, subprogram spec or body. + + Analyze (Unit_Node); + + -- The above call might have made Unit_Node an N_Subprogram_Body + -- from something else, so propagate any Acts_As_Spec flag. + + if Nkind (Unit_Node) = N_Subprogram_Body + and then Acts_As_Spec (Unit_Node) + then + Set_Acts_As_Spec (N); + end if; + + -- Treat compilation unit pragmas that appear after the library unit + + if Present (Pragmas_After (Aux_Decls_Node (N))) then + declare + Prag_Node : Node_Id := First (Pragmas_After (Aux_Decls_Node (N))); + + begin + while Present (Prag_Node) loop + Analyze (Prag_Node); + Next (Prag_Node); + end loop; + end; + end if; + + -- Generate distribution stub files if requested and no error + + if N = Main_Cunit + and then (Distribution_Stub_Mode = Generate_Receiver_Stub_Body + or else + Distribution_Stub_Mode = Generate_Caller_Stub_Body) + and then not Fatal_Error (Main_Unit) + then + if Is_RCI_Pkg_Spec_Or_Body (N) then + + -- Regular RCI package + + Add_Stub_Constructs (N); + + elsif (Nkind (Unit_Node) = N_Package_Declaration + and then Is_Shared_Passive (Defining_Entity + (Specification (Unit_Node)))) + or else (Nkind (Unit_Node) = N_Package_Body + and then + Is_Shared_Passive (Corresponding_Spec (Unit_Node))) + then + -- Shared passive package + + Add_Stub_Constructs (N); + + elsif Nkind (Unit_Node) = N_Package_Instantiation + and then + Is_Remote_Call_Interface + (Defining_Entity (Specification (Instance_Spec (Unit_Node)))) + then + -- Instantiation of a RCI generic package + + Add_Stub_Constructs (N); + end if; + + -- Reanalyze the unit with the new constructs + + Analyze (Unit_Node); + end if; + + if Nkind (Unit_Node) = N_Package_Declaration + or else Nkind (Unit_Node) in N_Generic_Declaration + or else Nkind (Unit_Node) = N_Package_Renaming_Declaration + or else Nkind (Unit_Node) = N_Subprogram_Declaration + then + Remove_Unit_From_Visibility (Defining_Entity (Unit_Node)); + + elsif Nkind (Unit_Node) = N_Package_Body + or else (Nkind (Unit_Node) = N_Subprogram_Body + and then not Acts_As_Spec (Unit_Node)) + then + -- Bodies that are not the main unit are compiled if they + -- are generic or contain generic or inlined units. Their + -- analysis brings in the context of the corresponding spec + -- (unit declaration) which must be removed as well, to + -- return the compilation environment to its proper state. + + Remove_Context (Lib_Unit); + Set_Is_Immediately_Visible (Defining_Entity (Unit (Lib_Unit)), False); + end if; + + -- Last step is to deinstall the context we just installed + -- as well as the unit just compiled. + + Remove_Context (N); + + -- If this is the main unit and we are generating code, we must + -- check that all generic units in the context have a body if they + -- need it, even if they have not been instantiated. In the absence + -- of .ali files for generic units, we must force the load of the body, + -- just to produce the proper error if the body is absent. We skip this + -- verification if the main unit itself is generic. + + if Get_Cunit_Unit_Number (N) = Main_Unit + and then Operating_Mode = Generate_Code + and then Expander_Active + then + -- Indicate that the main unit is now analyzed, to catch possible + -- circularities between it and generic bodies. Remove main unit + -- from visibility. This might seem superfluous, but the main unit + -- must not be visible in the generic body expansions that follow. + + Set_Analyzed (N, True); + Set_Is_Immediately_Visible (Cunit_Entity (Main_Unit), False); + + declare + Item : Node_Id; + Nam : Entity_Id; + Un : Unit_Number_Type; + + Save_Style_Check : constant Boolean := Opt.Style_Check; + Save_C_Restrict : constant Save_Compilation_Unit_Restrictions := + Compilation_Unit_Restrictions_Save; + + begin + Item := First (Context_Items (N)); + + while Present (Item) loop + + if Nkind (Item) = N_With_Clause + and then not Implicit_With (Item) + then + Nam := Entity (Name (Item)); + + if (Ekind (Nam) = E_Generic_Procedure + and then not Is_Intrinsic_Subprogram (Nam)) + or else (Ekind (Nam) = E_Generic_Function + and then not Is_Intrinsic_Subprogram (Nam)) + or else (Ekind (Nam) = E_Generic_Package + and then Unit_Requires_Body (Nam)) + then + Opt.Style_Check := False; + + if Present (Renamed_Object (Nam)) then + Un := + Load_Unit + (Load_Name => Get_Body_Name + (Get_Unit_Name + (Unit_Declaration_Node + (Renamed_Object (Nam)))), + Required => False, + Subunit => False, + Error_Node => N, + Renamings => True); + else + Un := + Load_Unit + (Load_Name => Get_Body_Name + (Get_Unit_Name (Item)), + Required => False, + Subunit => False, + Error_Node => N, + Renamings => True); + end if; + + if Un = No_Unit then + Error_Msg_NE + ("body of generic unit& not found", Item, Nam); + exit; + + elsif not Analyzed (Cunit (Un)) + and then Un /= Main_Unit + then + Opt.Style_Check := False; + Semantics (Cunit (Un)); + end if; + end if; + end if; + + Next (Item); + end loop; + + Style_Check := Save_Style_Check; + Compilation_Unit_Restrictions_Restore (Save_C_Restrict); + end; + end if; + + -- Deal with creating elaboration Boolean if needed. We create an + -- elaboration boolean only for units that come from source since + -- units manufactured by the compiler never need elab checks. + + if Comes_From_Source (N) + and then + (Nkind (Unit (N)) = N_Package_Declaration or else + Nkind (Unit (N)) = N_Generic_Package_Declaration or else + Nkind (Unit (N)) = N_Subprogram_Declaration or else + Nkind (Unit (N)) = N_Generic_Subprogram_Declaration) + then + declare + Loc : constant Source_Ptr := Sloc (N); + Unum : constant Unit_Number_Type := Get_Source_Unit (Loc); + + begin + Spec_Id := Defining_Entity (Unit (N)); + Generate_Definition (Spec_Id); + + -- See if an elaboration entity is required for possible + -- access before elaboration checking. Note that we must + -- allow for this even if -gnatE is not set, since a client + -- may be compiled in -gnatE mode and reference the entity. + + -- Case of units which do not require elaboration checks + + if + -- Pure units do not need checks + + Is_Pure (Spec_Id) + + -- Preelaborated units do not need checks + + or else Is_Preelaborated (Spec_Id) + + -- No checks needed if pagma Elaborate_Body present + + or else Has_Pragma_Elaborate_Body (Spec_Id) + + -- No checks needed if unit does not require a body + + or else not Unit_Requires_Body (Spec_Id) + + -- No checks needed for predefined files + + or else Is_Predefined_File_Name (Unit_File_Name (Unum)) + + -- No checks required if no separate spec + + or else Acts_As_Spec (N) + then + -- This is a case where we only need the entity for + -- checking to prevent multiple elaboration checks. + + Set_Elaboration_Entity_Required (Spec_Id, False); + + -- Case of elaboration entity is required for access before + -- elaboration checking (so certainly we must build it!) + + else + Set_Elaboration_Entity_Required (Spec_Id, True); + end if; + + Build_Elaboration_Entity (N, Spec_Id); + end; + end if; + + -- Finally, freeze the compilation unit entity. This for sure is needed + -- because of some warnings that can be output (see Freeze_Subprogram), + -- but may in general be required. If freezing actions result, place + -- them in the compilation unit actions list, and analyze them. + + declare + Loc : constant Source_Ptr := Sloc (N); + L : constant List_Id := + Freeze_Entity (Cunit_Entity (Current_Sem_Unit), Loc); + + begin + while Is_Non_Empty_List (L) loop + Insert_Library_Level_Action (Remove_Head (L)); + end loop; + end; + + Set_Analyzed (N); + + if Nkind (Unit_Node) = N_Package_Declaration + and then Get_Cunit_Unit_Number (N) /= Main_Unit + and then Front_End_Inlining + and then Expander_Active + then + Check_Body_For_Inlining (N, Defining_Entity (Unit_Node)); + end if; + end Analyze_Compilation_Unit; + + --------------------- + -- Analyze_Context -- + --------------------- + + procedure Analyze_Context (N : Node_Id) is + Item : Node_Id; + + begin + -- Loop through context items + + Item := First (Context_Items (N)); + while Present (Item) loop + + -- For with clause, analyze the with clause, and then update + -- the version, since we are dependent on a unit that we with. + + if Nkind (Item) = N_With_Clause then + + -- Skip analyzing with clause if no unit, nothing to do (this + -- happens for a with that references a non-existant unit) + + if Present (Library_Unit (Item)) then + Analyze (Item); + end if; + + if not Implicit_With (Item) then + Version_Update (N, Library_Unit (Item)); + end if; + + -- But skip use clauses at this stage, since we don't want to do + -- any installing of potentially use visible entities until we + -- we actually install the complete context (in Install_Context). + -- Otherwise things can get installed in the wrong context. + -- Similarly, pragmas are analyzed in Install_Context, after all + -- the implicit with's on parent units are generated. + + else + null; + end if; + + Next (Item); + end loop; + end Analyze_Context; + + ------------------------------- + -- Analyze_Package_Body_Stub -- + ------------------------------- + + procedure Analyze_Package_Body_Stub (N : Node_Id) is + Id : constant Entity_Id := Defining_Identifier (N); + Nam : Entity_Id; + + begin + -- The package declaration must be in the current declarative part. + + Check_Stub_Level (N); + Nam := Current_Entity_In_Scope (Id); + + if No (Nam) or else not Is_Package (Nam) then + Error_Msg_N ("missing specification for package stub", N); + + elsif Has_Completion (Nam) + and then Present (Corresponding_Body (Unit_Declaration_Node (Nam))) + then + Error_Msg_N ("duplicate or redundant stub for package", N); + + else + -- Indicate that the body of the package exists. If we are doing + -- only semantic analysis, the stub stands for the body. If we are + -- generating code, the existence of the body will be confirmed + -- when we load the proper body. + + Set_Has_Completion (Nam); + Set_Scope (Defining_Entity (N), Current_Scope); + Analyze_Proper_Body (N, Nam); + end if; + end Analyze_Package_Body_Stub; + + ------------------------- + -- Analyze_Proper_Body -- + ------------------------- + + procedure Analyze_Proper_Body (N : Node_Id; Nam : Entity_Id) is + Subunit_Name : constant Unit_Name_Type := Get_Unit_Name (N); + Unum : Unit_Number_Type; + Subunit_Not_Found : Boolean := False; + + procedure Optional_Subunit; + -- This procedure is called when the main unit is a stub, or when we + -- are not generating code. In such a case, we analyze the subunit if + -- present, which is user-friendly and in fact required for ASIS, but + -- we don't complain if the subunit is missing. + + ---------------------- + -- Optional_Subunit -- + ---------------------- + + procedure Optional_Subunit is + Comp_Unit : Node_Id; + + begin + -- Try to load subunit, but ignore any errors that occur during + -- the loading of the subunit, by using the special feature in + -- Errout to ignore all errors. Note that Fatal_Error will still + -- be set, so we will be able to check for this case below. + + Ignore_Errors_Enable := Ignore_Errors_Enable + 1; + Unum := + Load_Unit + (Load_Name => Subunit_Name, + Required => False, + Subunit => True, + Error_Node => N); + Ignore_Errors_Enable := Ignore_Errors_Enable - 1; + + -- All done if we successfully loaded the subunit + + if Unum /= No_Unit and then not Fatal_Error (Unum) then + Comp_Unit := Cunit (Unum); + + Set_Corresponding_Stub (Unit (Comp_Unit), N); + Analyze_Subunit (Comp_Unit); + Set_Library_Unit (N, Comp_Unit); + + elsif Unum = No_Unit + and then Present (Nam) + then + if Is_Protected_Type (Nam) then + Set_Corresponding_Body (Parent (Nam), Defining_Identifier (N)); + else + Set_Corresponding_Body ( + Unit_Declaration_Node (Nam), Defining_Identifier (N)); + end if; + end if; + end Optional_Subunit; + + -- Start of processing for Analyze_Proper_Body + + begin + -- If the subunit is already loaded, it means that the main unit + -- is a subunit, and that the current unit is one of its parents + -- which was being analyzed to provide the needed context for the + -- analysis of the subunit. In this case we analyze the subunit and + -- continue with the parent, without looking a subsequent subunits. + + if Is_Loaded (Subunit_Name) then + + -- If the proper body is already linked to the stub node, + -- the stub is in a generic unit and just needs analyzing. + + if Present (Library_Unit (N)) then + Set_Corresponding_Stub (Unit (Library_Unit (N)), N); + Analyze_Subunit (Library_Unit (N)); + + -- Otherwise we must load the subunit and link to it + + else + -- Load the subunit, this must work, since we originally + -- loaded the subunit earlier on. So this will not really + -- load it, just give access to it. + + Unum := + Load_Unit + (Load_Name => Subunit_Name, + Required => True, + Subunit => False, + Error_Node => N); + + -- And analyze the subunit in the parent context (note that we + -- do not call Semantics, since that would remove the parent + -- context). Because of this, we have to manually reset the + -- compiler state to Analyzing since it got destroyed by Load. + + if Unum /= No_Unit then + Compiler_State := Analyzing; + Set_Corresponding_Stub (Unit (Cunit (Unum)), N); + Analyze_Subunit (Cunit (Unum)); + Set_Library_Unit (N, Cunit (Unum)); + end if; + end if; + + -- If the main unit is a subunit, then we are just performing semantic + -- analysis on that subunit, and any other subunits of any parent unit + -- should be ignored, except that if we are building trees for ASIS + -- usage we want to annotate the stub properly. + + elsif Nkind (Unit (Cunit (Main_Unit))) = N_Subunit + and then Subunit_Name /= Unit_Name (Main_Unit) + then + if Tree_Output then + Optional_Subunit; + end if; + + -- But before we return, set the flag for unloaded subunits. This + -- will suppress junk warnings of variables in the same declarative + -- part (or a higher level one) that are in danger of looking unused + -- when in fact there might be a declaration in the subunit that we + -- do not intend to load. + + Unloaded_Subunits := True; + return; + + -- If the subunit is not already loaded, and we are generating code, + -- then this is the case where compilation started from the parent, + -- and we are generating code for an entire subunit tree. In that + -- case we definitely need to load the subunit. + + -- In order to continue the analysis with the rest of the parent, + -- and other subunits, we load the unit without requiring its + -- presence, and emit a warning if not found, rather than terminating + -- the compilation abruptly, as for other missing file problems. + + elsif Operating_Mode = Generate_Code then + + -- If the proper body is already linked to the stub node, + -- the stub is in a generic unit and just needs analyzing. + + -- We update the version. Although we are not technically + -- semantically dependent on the subunit, given our approach + -- of macro substitution of subunits, it makes sense to + -- include it in the version identification. + + if Present (Library_Unit (N)) then + Set_Corresponding_Stub (Unit (Library_Unit (N)), N); + Analyze_Subunit (Library_Unit (N)); + Version_Update (Cunit (Main_Unit), Library_Unit (N)); + + -- Otherwise we must load the subunit and link to it + + else + Unum := + Load_Unit + (Load_Name => Subunit_Name, + Required => False, + Subunit => True, + Error_Node => N); + + if Operating_Mode = Generate_Code + and then Unum = No_Unit + then + Error_Msg_Name_1 := Subunit_Name; + Error_Msg_Name_2 := + Get_File_Name (Subunit_Name, Subunit => True); + Error_Msg_N + ("subunit% in file{ not found!?", N); + Subunits_Missing := True; + Subunit_Not_Found := True; + end if; + + -- Load_Unit may reset Compiler_State, since it may have been + -- necessary to parse an additional units, so we make sure + -- that we reset it to the Analyzing state. + + Compiler_State := Analyzing; + + if Unum /= No_Unit and then not Fatal_Error (Unum) then + + if Debug_Flag_L then + Write_Str ("*** Loaded subunit from stub. Analyze"); + Write_Eol; + end if; + + declare + Comp_Unit : constant Node_Id := Cunit (Unum); + + begin + -- Check for child unit instead of subunit + + if Nkind (Unit (Comp_Unit)) /= N_Subunit then + Error_Msg_N + ("expected SEPARATE subunit, found child unit", + Cunit_Entity (Unum)); + + -- OK, we have a subunit, so go ahead and analyze it, + -- and set Scope of entity in stub, for ASIS use. + + else + Set_Corresponding_Stub (Unit (Comp_Unit), N); + Analyze_Subunit (Comp_Unit); + Set_Library_Unit (N, Comp_Unit); + + -- We update the version. Although we are not technically + -- semantically dependent on the subunit, given our + -- approach of macro substitution of subunits, it makes + -- sense to include it in the version identification. + + Version_Update (Cunit (Main_Unit), Comp_Unit); + end if; + end; + end if; + end if; + + -- The remaining case is when the subunit is not already loaded and + -- we are not generating code. In this case we are just performing + -- semantic analysis on the parent, and we are not interested in + -- the subunit. For subprograms, analyze the stub as a body. For + -- other entities the stub has already been marked as completed. + + else + Optional_Subunit; + end if; + + end Analyze_Proper_Body; + + ---------------------------------- + -- Analyze_Protected_Body_Stub -- + ---------------------------------- + + procedure Analyze_Protected_Body_Stub (N : Node_Id) is + Nam : Entity_Id := Current_Entity_In_Scope (Defining_Identifier (N)); + + begin + Check_Stub_Level (N); + + -- First occurence of name may have been as an incomplete type. + + if Present (Nam) and then Ekind (Nam) = E_Incomplete_Type then + Nam := Full_View (Nam); + end if; + + if No (Nam) + or else not Is_Protected_Type (Etype (Nam)) + then + Error_Msg_N ("missing specification for Protected body", N); + else + Set_Scope (Defining_Entity (N), Current_Scope); + Set_Has_Completion (Etype (Nam)); + Analyze_Proper_Body (N, Etype (Nam)); + end if; + end Analyze_Protected_Body_Stub; + + ---------------------------------- + -- Analyze_Subprogram_Body_Stub -- + ---------------------------------- + + -- A subprogram body stub can appear with or without a previous + -- specification. If there is one, the analysis of the body will + -- find it and verify conformance. The formals appearing in the + -- specification of the stub play no role, except for requiring an + -- additional conformance check. If there is no previous subprogram + -- declaration, the stub acts as a spec, and provides the defining + -- entity for the subprogram. + + procedure Analyze_Subprogram_Body_Stub (N : Node_Id) is + Decl : Node_Id; + + begin + Check_Stub_Level (N); + + -- Verify that the identifier for the stub is unique within this + -- declarative part. + + if Nkind (Parent (N)) = N_Block_Statement + or else Nkind (Parent (N)) = N_Package_Body + or else Nkind (Parent (N)) = N_Subprogram_Body + then + Decl := First (Declarations (Parent (N))); + + while Present (Decl) + and then Decl /= N + loop + if Nkind (Decl) = N_Subprogram_Body_Stub + and then (Chars (Defining_Unit_Name (Specification (Decl))) + = Chars (Defining_Unit_Name (Specification (N)))) + then + Error_Msg_N ("identifier for stub is not unique", N); + end if; + + Next (Decl); + end loop; + end if; + + -- Treat stub as a body, which checks conformance if there is a previous + -- declaration, or else introduces entity and its signature. + + Analyze_Subprogram_Body (N); + + if Errors_Detected = 0 then + Analyze_Proper_Body (N, Empty); + end if; + + end Analyze_Subprogram_Body_Stub; + + --------------------- + -- Analyze_Subunit -- + --------------------- + + -- A subunit is compiled either by itself (for semantic checking) + -- or as part of compiling the parent (for code generation). In + -- either case, by the time we actually process the subunit, the + -- parent has already been installed and analyzed. The node N is + -- a compilation unit, whose context needs to be treated here, + -- because we come directly here from the parent without calling + -- Analyze_Compilation_Unit. + + -- The compilation context includes the explicit context of the + -- subunit, and the context of the parent, together with the parent + -- itself. In order to compile the current context, we remove the + -- one inherited from the parent, in order to have a clean visibility + -- table. We restore the parent context before analyzing the proper + -- body itself. On exit, we remove only the explicit context of the + -- subunit. + + procedure Analyze_Subunit (N : Node_Id) is + Lib_Unit : constant Node_Id := Library_Unit (N); + Par_Unit : constant Entity_Id := Current_Scope; + + Lib_Spec : Node_Id := Library_Unit (Lib_Unit); + Num_Scopes : Int := 0; + Use_Clauses : array (1 .. Scope_Stack.Last) of Node_Id; + Enclosing_Child : Entity_Id := Empty; + + procedure Analyze_Subunit_Context; + -- Capture names in use clauses of the subunit. This must be done + -- before re-installing parent declarations, because items in the + -- context must not be hidden by declarations local to the parent. + + procedure Re_Install_Parents (L : Node_Id; Scop : Entity_Id); + -- Recursive procedure to restore scope of all ancestors of subunit, + -- from outermost in. If parent is not a subunit, the call to install + -- context installs context of spec and (if parent is a child unit) + -- the context of its parents as well. It is confusing that parents + -- should be treated differently in both cases, but the semantics are + -- just not identical. + + procedure Re_Install_Use_Clauses; + -- As part of the removal of the parent scope, the use clauses are + -- removed, to be reinstalled when the context of the subunit has + -- been analyzed. Use clauses may also have been affected by the + -- analysis of the context of the subunit, so they have to be applied + -- again, to insure that the compilation environment of the rest of + -- the parent unit is identical. + + procedure Remove_Scope; + -- Remove current scope from scope stack, and preserve the list + -- of use clauses in it, to be reinstalled after context is analyzed. + + ------------------------------ + -- Analyze_Subunit_Context -- + ------------------------------ + + procedure Analyze_Subunit_Context is + Item : Node_Id; + Nam : Node_Id; + Unit_Name : Entity_Id; + + begin + Analyze_Context (N); + Item := First (Context_Items (N)); + + -- make withed units immediately visible. If child unit, make the + -- ultimate parent immediately visible. + + while Present (Item) loop + + if Nkind (Item) = N_With_Clause then + Unit_Name := Entity (Name (Item)); + + while Is_Child_Unit (Unit_Name) loop + Set_Is_Visible_Child_Unit (Unit_Name); + Unit_Name := Scope (Unit_Name); + end loop; + + if not Is_Immediately_Visible (Unit_Name) then + Set_Is_Immediately_Visible (Unit_Name); + Set_Context_Installed (Item); + end if; + + elsif Nkind (Item) = N_Use_Package_Clause then + Nam := First (Names (Item)); + + while Present (Nam) loop + Analyze (Nam); + Next (Nam); + end loop; + + elsif Nkind (Item) = N_Use_Type_Clause then + Nam := First (Subtype_Marks (Item)); + + while Present (Nam) loop + Analyze (Nam); + Next (Nam); + end loop; + end if; + + Next (Item); + end loop; + + Item := First (Context_Items (N)); + + -- reset visibility of withed units. They will be made visible + -- again when we install the subunit context. + + while Present (Item) loop + + if Nkind (Item) = N_With_Clause then + Unit_Name := Entity (Name (Item)); + + while Is_Child_Unit (Unit_Name) loop + Set_Is_Visible_Child_Unit (Unit_Name, False); + Unit_Name := Scope (Unit_Name); + end loop; + + if Context_Installed (Item) then + Set_Is_Immediately_Visible (Unit_Name, False); + Set_Context_Installed (Item, False); + end if; + end if; + + Next (Item); + end loop; + + end Analyze_Subunit_Context; + + ------------------------ + -- Re_Install_Parents -- + ------------------------ + + procedure Re_Install_Parents (L : Node_Id; Scop : Entity_Id) is + E : Entity_Id; + + begin + if Nkind (Unit (L)) = N_Subunit then + Re_Install_Parents (Library_Unit (L), Scope (Scop)); + end if; + + Install_Context (L); + + -- If the subunit occurs within a child unit, we must restore the + -- immediate visibility of any siblings that may occur in context. + + if Present (Enclosing_Child) then + Install_Siblings (Enclosing_Child, L); + end if; + + New_Scope (Scop); + + if Scop /= Par_Unit then + Set_Is_Immediately_Visible (Scop); + end if; + + E := First_Entity (Current_Scope); + + while Present (E) loop + Set_Is_Immediately_Visible (E); + Next_Entity (E); + end loop; + + -- A subunit appears within a body, and for a nested subunits + -- all the parents are bodies. Restore full visibility of their + -- private entities. + + if Ekind (Scop) = E_Package then + Set_In_Package_Body (Scop); + Install_Private_Declarations (Scop); + end if; + end Re_Install_Parents; + + ---------------------------- + -- Re_Install_Use_Clauses -- + ---------------------------- + + procedure Re_Install_Use_Clauses is + U : Node_Id; + + begin + for J in reverse 1 .. Num_Scopes loop + U := Use_Clauses (J); + Scope_Stack.Table (Scope_Stack.Last - J + 1).First_Use_Clause := U; + Install_Use_Clauses (U); + end loop; + end Re_Install_Use_Clauses; + + ------------------ + -- Remove_Scope -- + ------------------ + + procedure Remove_Scope is + E : Entity_Id; + + begin + Num_Scopes := Num_Scopes + 1; + Use_Clauses (Num_Scopes) := + Scope_Stack.Table (Scope_Stack.Last).First_Use_Clause; + E := First_Entity (Current_Scope); + + while Present (E) loop + Set_Is_Immediately_Visible (E, False); + Next_Entity (E); + end loop; + + if Is_Child_Unit (Current_Scope) then + Enclosing_Child := Current_Scope; + end if; + + Pop_Scope; + end Remove_Scope; + + -- Start of processing for Analyze_Subunit + + begin + if not Is_Empty_List (Context_Items (N)) then + + -- Save current use clauses. + + Remove_Scope; + Remove_Context (Lib_Unit); + + -- Now remove parents and their context, including enclosing + -- subunits and the outer parent body which is not a subunit. + + if Present (Lib_Spec) then + Remove_Context (Lib_Spec); + + while Nkind (Unit (Lib_Spec)) = N_Subunit loop + Lib_Spec := Library_Unit (Lib_Spec); + Remove_Scope; + Remove_Context (Lib_Spec); + end loop; + + if Nkind (Unit (Lib_Unit)) = N_Subunit then + Remove_Scope; + end if; + + if Nkind (Unit (Lib_Spec)) = N_Package_Body then + Remove_Context (Library_Unit (Lib_Spec)); + end if; + end if; + + Analyze_Subunit_Context; + Re_Install_Parents (Lib_Unit, Par_Unit); + + -- If the context includes a child unit of the parent of the + -- subunit, the parent will have been removed from visibility, + -- after compiling that cousin in the context. The visibility + -- of the parent must be restored now. This also applies if the + -- context includes another subunit of the same parent which in + -- turn includes a child unit in its context. + + if Ekind (Par_Unit) = E_Package then + if not Is_Immediately_Visible (Par_Unit) + or else (Present (First_Entity (Par_Unit)) + and then not Is_Immediately_Visible + (First_Entity (Par_Unit))) + then + Set_Is_Immediately_Visible (Par_Unit); + Install_Visible_Declarations (Par_Unit); + Install_Private_Declarations (Par_Unit); + end if; + end if; + + Re_Install_Use_Clauses; + Install_Context (N); + + -- If the subunit is within a child unit, then siblings of any + -- parent unit that appear in the context clause of the subunit + -- must also be made immediately visible. + + if Present (Enclosing_Child) then + Install_Siblings (Enclosing_Child, N); + end if; + + end if; + + Analyze (Proper_Body (Unit (N))); + Remove_Context (N); + + end Analyze_Subunit; + + ---------------------------- + -- Analyze_Task_Body_Stub -- + ---------------------------- + + procedure Analyze_Task_Body_Stub (N : Node_Id) is + Nam : Entity_Id := Current_Entity_In_Scope (Defining_Identifier (N)); + Loc : constant Source_Ptr := Sloc (N); + + begin + Check_Stub_Level (N); + + -- First occurence of name may have been as an incomplete type. + + if Present (Nam) and then Ekind (Nam) = E_Incomplete_Type then + Nam := Full_View (Nam); + end if; + + if No (Nam) + or else not Is_Task_Type (Etype (Nam)) + then + Error_Msg_N ("missing specification for task body", N); + else + Set_Scope (Defining_Entity (N), Current_Scope); + Set_Has_Completion (Etype (Nam)); + Analyze_Proper_Body (N, Etype (Nam)); + + -- Set elaboration flag to indicate that entity is callable. + -- This cannot be done in the expansion of the body itself, + -- because the proper body is not in a declarative part. This + -- is only done if expansion is active, because the context + -- may be generic and the flag not defined yet. + + if Expander_Active then + Insert_After (N, + Make_Assignment_Statement (Loc, + Name => + Make_Identifier (Loc, + New_External_Name (Chars (Etype (Nam)), 'E')), + Expression => New_Reference_To (Standard_True, Loc))); + end if; + + end if; + end Analyze_Task_Body_Stub; + + ------------------------- + -- Analyze_With_Clause -- + ------------------------- + + -- Analyze the declaration of a unit in a with clause. At end, + -- label the with clause with the defining entity for the unit. + + procedure Analyze_With_Clause (N : Node_Id) is + Unit_Kind : constant Node_Kind := Nkind (Unit (Library_Unit (N))); + E_Name : Entity_Id; + Par_Name : Entity_Id; + Pref : Node_Id; + U : Node_Id; + + Intunit : Boolean; + -- Set True if the unit currently being compiled is an internal unit + + Save_Style_Check : constant Boolean := Opt.Style_Check; + Save_C_Restrict : constant Save_Compilation_Unit_Restrictions := + Compilation_Unit_Restrictions_Save; + + begin + -- We reset ordinary style checking during the analysis of a with'ed + -- unit, but we do NOT reset GNAT special analysis mode (the latter + -- definitely *does* apply to with'ed units). + + if not GNAT_Mode then + Style_Check := False; + end if; + + -- If the library unit is a predefined unit, and we are in no + -- run time mode, then temporarily reset No_Run_Time mode for the + -- analysis of the with'ed unit. The No_Run_Time pragma does not + -- prevent explicit with'ing of run-time units. + + if No_Run_Time + and then + Is_Predefined_File_Name + (Unit_File_Name (Get_Source_Unit (Unit (Library_Unit (N))))) + then + No_Run_Time := False; + Semantics (Library_Unit (N)); + No_Run_Time := True; + + else + Semantics (Library_Unit (N)); + end if; + + U := Unit (Library_Unit (N)); + Intunit := Is_Internal_File_Name (Unit_File_Name (Current_Sem_Unit)); + + -- Following checks are skipped for dummy packages (those supplied + -- for with's where no matching file could be found). Such packages + -- are identified by the Sloc value being set to No_Location + + if Sloc (U) /= No_Location then + + -- Check restrictions, except that we skip the check if this + -- is an internal unit unless we are compiling the internal + -- unit as the main unit. We also skip this for dummy packages. + + if not Intunit or else Current_Sem_Unit = Main_Unit then + Check_Restricted_Unit (Unit_Name (Get_Source_Unit (U)), N); + end if; + + -- Check for inappropriate with of internal implementation unit + -- if we are currently compiling the main unit and the main unit + -- is itself not an internal unit. + + if Implementation_Unit_Warnings + and then Current_Sem_Unit = Main_Unit + and then Implementation_Unit (Get_Source_Unit (U)) + and then not Intunit + then + Error_Msg_N ("& is an internal 'G'N'A'T unit?", Name (N)); + Error_Msg_N + ("\use of this unit is non-portable and version-dependent?", + Name (N)); + end if; + end if; + + -- Semantic analysis of a generic unit is performed on a copy of + -- the original tree. Retrieve the entity on which semantic info + -- actually appears. + + if Unit_Kind in N_Generic_Declaration then + E_Name := Defining_Entity (U); + + -- Note: in the following test, Unit_Kind is the original Nkind, but + -- in the case of an instantiation, the call to Semantics above will + -- have replaced the unit by its instantiated version. + + elsif Unit_Kind = N_Package_Instantiation + and then Nkind (U) = N_Package_Body + then + -- Instantiation node is replaced with body of instance. + -- Unit name is defining unit name in corresponding spec. + + E_Name := Corresponding_Spec (U); + + elsif Unit_Kind = N_Package_Instantiation + and then Nkind (U) = N_Package_Instantiation + then + -- If the instance has not been rewritten as a package declaration, + -- then it appeared already in a previous with clause. Retrieve + -- the entity from the previous instance. + + E_Name := Defining_Entity (Specification (Instance_Spec (U))); + + elsif Unit_Kind = N_Procedure_Instantiation + or else Unit_Kind = N_Function_Instantiation + then + -- Instantiation node is replaced with a package that contains + -- renaming declarations and instance itself. The subprogram + -- Instance is declared in the visible part of the wrapper package. + + E_Name := First_Entity (Defining_Entity (U)); + + while Present (E_Name) loop + exit when Is_Subprogram (E_Name) + and then Is_Generic_Instance (E_Name); + E_Name := Next_Entity (E_Name); + end loop; + + elsif Unit_Kind = N_Package_Renaming_Declaration + or else Unit_Kind in N_Generic_Renaming_Declaration + then + E_Name := Defining_Entity (U); + + elsif Unit_Kind = N_Subprogram_Body + and then Nkind (Name (N)) = N_Selected_Component + and then not Acts_As_Spec (Library_Unit (N)) + then + -- For a child unit that has no spec, one has been created and + -- analyzed. The entity required is that of the spec. + + E_Name := Corresponding_Spec (U); + + else + E_Name := Defining_Entity (U); + end if; + + if Nkind (Name (N)) = N_Selected_Component then + + -- Child unit in a with clause + + Change_Selected_Component_To_Expanded_Name (Name (N)); + end if; + + -- Restore style checks and restrictions + + Style_Check := Save_Style_Check; + Compilation_Unit_Restrictions_Restore (Save_C_Restrict); + + -- Record the reference, but do NOT set the unit as referenced, we + -- want to consider the unit as unreferenced if this is the only + -- reference that occurs. + + Set_Entity_With_Style_Check (Name (N), E_Name); + Generate_Reference (E_Name, Name (N), Set_Ref => False); + + if Is_Child_Unit (E_Name) then + Pref := Prefix (Name (N)); + Par_Name := Scope (E_Name); + + while Nkind (Pref) = N_Selected_Component loop + Change_Selected_Component_To_Expanded_Name (Pref); + Set_Entity_With_Style_Check (Pref, Par_Name); + + Generate_Reference (Par_Name, Pref); + Pref := Prefix (Pref); + Par_Name := Scope (Par_Name); + end loop; + + if Present (Entity (Pref)) + and then not Analyzed (Parent (Parent (Entity (Pref)))) + then + -- If the entity is set without its unit being compiled, + -- the original parent is a renaming, and Par_Name is the + -- renamed entity. For visibility purposes, we need the + -- original entity, which must be analyzed now, because + -- Load_Unit retrieves directly the renamed unit, and the + -- renaming declaration itself has not been analyzed. + + Analyze (Parent (Parent (Entity (Pref)))); + pragma Assert (Renamed_Object (Entity (Pref)) = Par_Name); + Par_Name := Entity (Pref); + end if; + + Set_Entity_With_Style_Check (Pref, Par_Name); + Generate_Reference (Par_Name, Pref); + end if; + + -- If the withed unit is System, and a system extension pragma is + -- present, compile the extension now, rather than waiting for + -- a visibility check on a specific entity. + + if Chars (E_Name) = Name_System + and then Scope (E_Name) = Standard_Standard + and then Present (System_Extend_Pragma_Arg) + and then Present_System_Aux (N) + then + -- If the extension is not present, an error will have been emitted. + + null; + end if; + end Analyze_With_Clause; + + ------------------------------ + -- Analyze_With_Type_Clause -- + ------------------------------ + + procedure Analyze_With_Type_Clause (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Nam : Node_Id := Name (N); + Pack : Node_Id; + Decl : Node_Id; + P : Entity_Id; + Unum : Unit_Number_Type; + Sel : Node_Id; + + procedure Decorate_Tagged_Type (T : Entity_Id; Kind : Entity_Kind); + -- Set basic attributes of type, including its class_wide type. + + function In_Chain (E : Entity_Id) return Boolean; + -- Check that the imported type is not already in the homonym chain, + -- for example through a with_type clause in a parent unit. + + -------------------------- + -- Decorate_Tagged_Type -- + -------------------------- + + procedure Decorate_Tagged_Type (T : Entity_Id; Kind : Entity_Kind) is + CW : Entity_Id; + + begin + Set_Ekind (T, E_Record_Type); + Set_Is_Tagged_Type (T); + Set_Etype (T, T); + Set_From_With_Type (T); + Set_Scope (T, P); + + if not In_Chain (T) then + Set_Homonym (T, Current_Entity (T)); + Set_Current_Entity (T); + end if; + + -- Build bogus class_wide type, if not previously done. + + if No (Class_Wide_Type (T)) then + CW := Make_Defining_Identifier (Loc, New_Internal_Name ('S')); + + Set_Ekind (CW, E_Class_Wide_Type); + Set_Etype (CW, T); + Set_Scope (CW, P); + Set_Is_Tagged_Type (CW); + Set_Is_First_Subtype (CW, True); + Init_Size_Align (CW); + Set_Has_Unknown_Discriminants + (CW, True); + Set_Class_Wide_Type (CW, CW); + Set_Equivalent_Type (CW, Empty); + Set_From_With_Type (CW); + + Set_Class_Wide_Type (T, CW); + end if; + end Decorate_Tagged_Type; + + -------------- + -- In_Chain -- + -------------- + + function In_Chain (E : Entity_Id) return Boolean is + H : Entity_Id := Current_Entity (E); + + begin + while Present (H) loop + + if H = E then + return True; + else + H := Homonym (H); + end if; + end loop; + + return False; + end In_Chain; + + -- Start of processing for Analyze_With_Type_Clause + + begin + if Nkind (Nam) = N_Selected_Component then + Pack := New_Copy_Tree (Prefix (Nam)); + Sel := Selector_Name (Nam); + + else + Error_Msg_N ("illegal name for imported type", Nam); + return; + end if; + + Decl := + Make_Package_Declaration (Loc, + Specification => + (Make_Package_Specification (Loc, + Defining_Unit_Name => Pack, + Visible_Declarations => New_List, + End_Label => Empty))); + + Unum := + Load_Unit + (Load_Name => Get_Unit_Name (Decl), + Required => True, + Subunit => False, + Error_Node => Nam); + + if Unum = No_Unit + or else Nkind (Unit (Cunit (Unum))) /= N_Package_Declaration + then + Error_Msg_N ("imported type must be declared in package", Nam); + return; + + elsif Unum = Current_Sem_Unit then + + -- If type is defined in unit being analyzed, then the clause + -- is redundant. + + return; + + else + P := Cunit_Entity (Unum); + end if; + + -- Find declaration for imported type, and set its basic attributes + -- if it has not been analyzed (which will be the case if there is + -- circular dependence). + + declare + Decl : Node_Id; + Typ : Entity_Id; + + begin + if not Analyzed (Cunit (Unum)) + and then not From_With_Type (P) + then + Set_Ekind (P, E_Package); + Set_Etype (P, Standard_Void_Type); + Set_From_With_Type (P); + Set_Scope (P, Standard_Standard); + Set_Homonym (P, Current_Entity (P)); + Set_Current_Entity (P); + + elsif Analyzed (Cunit (Unum)) + and then Is_Child_Unit (P) + then + -- If the child unit is already in scope, indicate that it is + -- visible, and remains so after intervening calls to rtsfind. + + Set_Is_Visible_Child_Unit (P); + end if; + + if Nkind (Parent (P)) = N_Defining_Program_Unit_Name then + + -- Make parent packages visible. + + declare + Parent_Comp : Node_Id; + Parent_Id : Entity_Id; + Child : Entity_Id; + + begin + Child := P; + Parent_Comp := Parent_Spec (Unit (Cunit (Unum))); + + loop + Parent_Id := Defining_Entity (Unit (Parent_Comp)); + Set_Scope (Child, Parent_Id); + + -- The type may be imported from a child unit, in which + -- case the current compilation appears in the name. Do + -- not change its visibility here because it will conflict + -- with the subsequent normal processing. + + if not Analyzed (Unit_Declaration_Node (Parent_Id)) + and then Parent_Id /= Cunit_Entity (Current_Sem_Unit) + then + Set_Ekind (Parent_Id, E_Package); + Set_Etype (Parent_Id, Standard_Void_Type); + + -- The same package may appear is several with_type + -- clauses. + + if not From_With_Type (Parent_Id) then + Set_Homonym (Parent_Id, Current_Entity (Parent_Id)); + Set_Current_Entity (Parent_Id); + Set_From_With_Type (Parent_Id); + end if; + end if; + + Set_Is_Immediately_Visible (Parent_Id); + + Child := Parent_Id; + Parent_Comp := Parent_Spec (Unit (Parent_Comp)); + exit when No (Parent_Comp); + end loop; + + Set_Scope (Parent_Id, Standard_Standard); + end; + end if; + + -- Even if analyzed, the package may not be currently visible. It + -- must be while the with_type clause is active. + + Set_Is_Immediately_Visible (P); + + Decl := + First (Visible_Declarations (Specification (Unit (Cunit (Unum))))); + + while Present (Decl) loop + + if Nkind (Decl) = N_Full_Type_Declaration + and then Chars (Defining_Identifier (Decl)) = Chars (Sel) + then + Typ := Defining_Identifier (Decl); + + if Tagged_Present (N) then + + -- The declaration must indicate that this is a tagged + -- type or a type extension. + + if (Nkind (Type_Definition (Decl)) = N_Record_Definition + and then Tagged_Present (Type_Definition (Decl))) + or else + (Nkind (Type_Definition (Decl)) + = N_Derived_Type_Definition + and then Present + (Record_Extension_Part (Type_Definition (Decl)))) + then + null; + else + Error_Msg_N ("imported type is not a tagged type", Nam); + return; + end if; + + if not Analyzed (Decl) then + + -- Unit is not currently visible. Add basic attributes + -- to type and build its class-wide type. + + Init_Size_Align (Typ); + Decorate_Tagged_Type (Typ, E_Record_Type); + end if; + + else + if Nkind (Type_Definition (Decl)) + /= N_Access_To_Object_Definition + then + Error_Msg_N + ("imported type is not an access type", Nam); + + elsif not Analyzed (Decl) then + Set_Ekind (Typ, E_Access_Type); + Set_Etype (Typ, Typ); + Set_Scope (Typ, P); + Init_Size (Typ, System_Address_Size); + Init_Alignment (Typ); + Set_Directly_Designated_Type (Typ, Standard_Integer); + Set_From_With_Type (Typ); + + if not In_Chain (Typ) then + Set_Homonym (Typ, Current_Entity (Typ)); + Set_Current_Entity (Typ); + end if; + end if; + end if; + + Set_Entity (Sel, Typ); + return; + + elsif ((Nkind (Decl) = N_Private_Type_Declaration + and then Tagged_Present (Decl)) + or else (Nkind (Decl) = N_Private_Extension_Declaration)) + and then Chars (Defining_Identifier (Decl)) = Chars (Sel) + then + Typ := Defining_Identifier (Decl); + + if not Tagged_Present (N) then + Error_Msg_N ("type must be declared tagged", N); + + elsif not Analyzed (Decl) then + Decorate_Tagged_Type (Typ, E_Private_Type); + end if; + + Set_Entity (Sel, Typ); + Set_From_With_Type (Typ); + return; + end if; + + Decl := Next (Decl); + end loop; + + Error_Msg_NE ("not a visible access or tagged type in&", Nam, P); + end; + end Analyze_With_Type_Clause; + + ----------------------------- + -- Check_With_Type_Clauses -- + ----------------------------- + + procedure Check_With_Type_Clauses (N : Node_Id) is + Lib_Unit : constant Node_Id := Unit (N); + + procedure Check_Parent_Context (U : Node_Id); + -- Examine context items of parent unit to locate with_type clauses. + + -------------------------- + -- Check_Parent_Context -- + -------------------------- + + procedure Check_Parent_Context (U : Node_Id) is + Item : Node_Id; + + begin + Item := First (Context_Items (U)); + while Present (Item) loop + if Nkind (Item) = N_With_Type_Clause + and then not Error_Posted (Item) + and then + From_With_Type (Scope (Entity (Selector_Name (Name (Item))))) + then + Error_Msg_Sloc := Sloc (Item); + Error_Msg_N ("Missing With_Clause for With_Type_Clause#", N); + end if; + + Next (Item); + end loop; + end Check_Parent_Context; + + -- Start of processing for Check_With_Type_Clauses + + begin + if Extensions_Allowed + and then (Nkind (Lib_Unit) = N_Package_Body + or else Nkind (Lib_Unit) = N_Subprogram_Body) + then + Check_Parent_Context (Library_Unit (N)); + if Is_Child_Spec (Unit (Library_Unit (N))) then + Check_Parent_Context (Parent_Spec (Unit (Library_Unit (N)))); + end if; + end if; + end Check_With_Type_Clauses; + + ------------------------------ + -- Check_Private_Child_Unit -- + ------------------------------ + + procedure Check_Private_Child_Unit (N : Node_Id) is + Lib_Unit : constant Node_Id := Unit (N); + Item : Node_Id; + Curr_Unit : Entity_Id; + Sub_Parent : Node_Id; + Priv_Child : Entity_Id; + Par_Lib : Entity_Id; + Par_Spec : Node_Id; + + function Is_Private_Library_Unit (Unit : Entity_Id) return Boolean; + -- Returns true if and only if the library unit is declared with + -- an explicit designation of private. + + function Is_Private_Library_Unit (Unit : Entity_Id) return Boolean is + begin + return Private_Present (Parent (Unit_Declaration_Node (Unit))); + end Is_Private_Library_Unit; + + -- Start of processing for Check_Private_Child_Unit + + begin + if Nkind (Lib_Unit) = N_Package_Body + or else Nkind (Lib_Unit) = N_Subprogram_Body + then + Curr_Unit := Defining_Entity (Unit (Library_Unit (N))); + Par_Lib := Curr_Unit; + + elsif Nkind (Lib_Unit) = N_Subunit then + + -- The parent is itself a body. The parent entity is to be found + -- in the corresponding spec. + + Sub_Parent := Library_Unit (N); + Curr_Unit := Defining_Entity (Unit (Library_Unit (Sub_Parent))); + + -- If the parent itself is a subunit, Curr_Unit is the entity + -- of the enclosing body, retrieve the spec entity which is + -- the proper ancestor we need for the following tests. + + if Ekind (Curr_Unit) = E_Package_Body then + Curr_Unit := Spec_Entity (Curr_Unit); + end if; + + Par_Lib := Curr_Unit; + + else + Curr_Unit := Defining_Entity (Lib_Unit); + + Par_Lib := Curr_Unit; + Par_Spec := Parent_Spec (Lib_Unit); + + if No (Par_Spec) then + Par_Lib := Empty; + else + Par_Lib := Defining_Entity (Unit (Par_Spec)); + end if; + end if; + + -- Loop through context items + + Item := First (Context_Items (N)); + while Present (Item) loop + + if Nkind (Item) = N_With_Clause + and then not Implicit_With (Item) + and then Is_Private_Descendant (Entity (Name (Item))) + then + Priv_Child := Entity (Name (Item)); + + declare + Curr_Parent : Entity_Id := Par_Lib; + Child_Parent : Entity_Id := Scope (Priv_Child); + Prv_Ancestor : Entity_Id := Child_Parent; + Curr_Private : Boolean := Is_Private_Library_Unit (Curr_Unit); + + begin + -- If the child unit is a public child then locate + -- the nearest private ancestor; Child_Parent will + -- then be set to the parent of that ancestor. + + if not Is_Private_Library_Unit (Priv_Child) then + while Present (Prv_Ancestor) + and then not Is_Private_Library_Unit (Prv_Ancestor) + loop + Prv_Ancestor := Scope (Prv_Ancestor); + end loop; + + if Present (Prv_Ancestor) then + Child_Parent := Scope (Prv_Ancestor); + end if; + end if; + + while Present (Curr_Parent) + and then Curr_Parent /= Standard_Standard + and then Curr_Parent /= Child_Parent + loop + Curr_Private := + Curr_Private or else Is_Private_Library_Unit (Curr_Parent); + Curr_Parent := Scope (Curr_Parent); + end loop; + + if not Present (Curr_Parent) then + Curr_Parent := Standard_Standard; + end if; + + if Curr_Parent /= Child_Parent then + + if Ekind (Priv_Child) = E_Generic_Package + and then Chars (Priv_Child) in Text_IO_Package_Name + and then Chars (Scope (Scope (Priv_Child))) = Name_Ada + then + Error_Msg_NE + ("& is a nested package, not a compilation unit", + Name (Item), Priv_Child); + + else + Error_Msg_N + ("unit in with clause is private child unit!", Item); + Error_Msg_NE + ("current unit must also have parent&!", + Item, Child_Parent); + end if; + + elsif not Curr_Private + and then Nkind (Lib_Unit) /= N_Package_Body + and then Nkind (Lib_Unit) /= N_Subprogram_Body + and then Nkind (Lib_Unit) /= N_Subunit + then + Error_Msg_NE + ("current unit must also be private descendant of&", + Item, Child_Parent); + end if; + end; + end if; + + Next (Item); + end loop; + + end Check_Private_Child_Unit; + + ---------------------- + -- Check_Stub_Level -- + ---------------------- + + procedure Check_Stub_Level (N : Node_Id) is + Par : constant Node_Id := Parent (N); + Kind : constant Node_Kind := Nkind (Par); + + begin + if (Kind = N_Package_Body + or else Kind = N_Subprogram_Body + or else Kind = N_Task_Body + or else Kind = N_Protected_Body) + + and then (Nkind (Parent (Par)) = N_Compilation_Unit + or else Nkind (Parent (Par)) = N_Subunit) + then + null; + + -- In an instance, a missing stub appears at any level. A warning + -- message will have been emitted already for the missing file. + + elsif not In_Instance then + Error_Msg_N ("stub cannot appear in an inner scope", N); + + elsif Expander_Active then + Error_Msg_N ("missing proper body", N); + end if; + end Check_Stub_Level; + + ------------------------ + -- Expand_With_Clause -- + ------------------------ + + procedure Expand_With_Clause (Nam : Node_Id; N : Node_Id) is + Loc : constant Source_Ptr := Sloc (Nam); + Ent : constant Entity_Id := Entity (Nam); + Withn : Node_Id; + P : Node_Id; + + function Build_Unit_Name (Nam : Node_Id) return Node_Id; + + function Build_Unit_Name (Nam : Node_Id) return Node_Id is + Result : Node_Id; + + begin + if Nkind (Nam) = N_Identifier then + return New_Occurrence_Of (Entity (Nam), Loc); + + else + Result := + Make_Expanded_Name (Loc, + Chars => Chars (Entity (Nam)), + Prefix => Build_Unit_Name (Prefix (Nam)), + Selector_Name => New_Occurrence_Of (Entity (Nam), Loc)); + Set_Entity (Result, Entity (Nam)); + return Result; + end if; + end Build_Unit_Name; + + begin + New_Nodes_OK := New_Nodes_OK + 1; + Withn := + Make_With_Clause (Loc, Name => Build_Unit_Name (Nam)); + + P := Parent (Unit_Declaration_Node (Ent)); + Set_Library_Unit (Withn, P); + Set_Corresponding_Spec (Withn, Ent); + Set_First_Name (Withn, True); + Set_Implicit_With (Withn, True); + + Prepend (Withn, Context_Items (N)); + Mark_Rewrite_Insertion (Withn); + Install_Withed_Unit (Withn); + + if Nkind (Nam) = N_Expanded_Name then + Expand_With_Clause (Prefix (Nam), N); + end if; + + New_Nodes_OK := New_Nodes_OK - 1; + end Expand_With_Clause; + + ----------------------------- + -- Implicit_With_On_Parent -- + ----------------------------- + + procedure Implicit_With_On_Parent + (Child_Unit : Node_Id; + N : Node_Id) + is + Loc : constant Source_Ptr := Sloc (N); + P : constant Node_Id := Parent_Spec (Child_Unit); + P_Unit : constant Node_Id := Unit (P); + + P_Name : Entity_Id := Defining_Entity (P_Unit); + Withn : Node_Id; + + function Build_Ancestor_Name (P : Node_Id) return Node_Id; + -- Build prefix of child unit name. Recurse if needed. + + function Build_Unit_Name return Node_Id; + -- If the unit is a child unit, build qualified name with all + -- ancestors. + + ------------------------- + -- Build_Ancestor_Name -- + ------------------------- + + function Build_Ancestor_Name (P : Node_Id) return Node_Id is + P_Ref : Node_Id := New_Reference_To (Defining_Entity (P), Loc); + + begin + if No (Parent_Spec (P)) then + return P_Ref; + else + return + Make_Selected_Component (Loc, + Prefix => Build_Ancestor_Name (Unit (Parent_Spec (P))), + Selector_Name => P_Ref); + end if; + end Build_Ancestor_Name; + + --------------------- + -- Build_Unit_Name -- + --------------------- + + function Build_Unit_Name return Node_Id is + Result : Node_Id; + + begin + if No (Parent_Spec (P_Unit)) then + return New_Reference_To (P_Name, Loc); + else + Result := + Make_Expanded_Name (Loc, + Chars => Chars (P_Name), + Prefix => Build_Ancestor_Name (Unit (Parent_Spec (P_Unit))), + Selector_Name => New_Reference_To (P_Name, Loc)); + Set_Entity (Result, P_Name); + return Result; + end if; + end Build_Unit_Name; + + -- Start of processing for Implicit_With_On_Parent + + begin + New_Nodes_OK := New_Nodes_OK + 1; + Withn := Make_With_Clause (Loc, Name => Build_Unit_Name); + + Set_Library_Unit (Withn, P); + Set_Corresponding_Spec (Withn, P_Name); + Set_First_Name (Withn, True); + Set_Implicit_With (Withn, True); + + -- Node is placed at the beginning of the context items, so that + -- subsequent use clauses on the parent can be validated. + + Prepend (Withn, Context_Items (N)); + Mark_Rewrite_Insertion (Withn); + Install_Withed_Unit (Withn); + + if Is_Child_Spec (P_Unit) then + Implicit_With_On_Parent (P_Unit, N); + end if; + New_Nodes_OK := New_Nodes_OK - 1; + end Implicit_With_On_Parent; + + --------------------- + -- Install_Context -- + --------------------- + + procedure Install_Context (N : Node_Id) is + Lib_Unit : Node_Id := Unit (N); + + begin + Install_Context_Clauses (N); + + if Is_Child_Spec (Lib_Unit) then + Install_Parents (Lib_Unit, Private_Present (Parent (Lib_Unit))); + end if; + + Check_With_Type_Clauses (N); + end Install_Context; + + ----------------------------- + -- Install_Context_Clauses -- + ----------------------------- + + procedure Install_Context_Clauses (N : Node_Id) is + Lib_Unit : Node_Id := Unit (N); + Item : Node_Id; + Uname_Node : Entity_Id; + Check_Private : Boolean := False; + Decl_Node : Node_Id; + Lib_Parent : Entity_Id; + + begin + -- Loop through context clauses to find the with/use clauses + + Item := First (Context_Items (N)); + while Present (Item) loop + + -- Case of explicit WITH clause + + if Nkind (Item) = N_With_Clause + and then not Implicit_With (Item) + then + -- If Name (Item) is not an entity name, something is wrong, and + -- this will be detected in due course, for now ignore the item + + if not Is_Entity_Name (Name (Item)) then + goto Continue; + end if; + + Uname_Node := Entity (Name (Item)); + + if Is_Private_Descendant (Uname_Node) then + Check_Private := True; + end if; + + Install_Withed_Unit (Item); + + Decl_Node := Unit_Declaration_Node (Uname_Node); + + -- If the unit is a subprogram instance, it appears nested + -- within a package that carries the parent information. + + if Is_Generic_Instance (Uname_Node) + and then Ekind (Uname_Node) /= E_Package + then + Decl_Node := Parent (Parent (Decl_Node)); + end if; + + if Is_Child_Spec (Decl_Node) then + if Nkind (Name (Item)) = N_Expanded_Name then + Expand_With_Clause (Prefix (Name (Item)), N); + else + -- if not an expanded name, the child unit must be a + -- renaming, nothing to do. + + null; + end if; + + elsif Nkind (Decl_Node) = N_Subprogram_Body + and then not Acts_As_Spec (Parent (Decl_Node)) + and then Is_Child_Spec (Unit (Library_Unit (Parent (Decl_Node)))) + then + Implicit_With_On_Parent + (Unit (Library_Unit (Parent (Decl_Node))), N); + end if; + + -- Check license conditions unless this is a dummy unit + + if Sloc (Library_Unit (Item)) /= No_Location then + License_Check : declare + Withl : constant License_Type := + License (Source_Index + (Get_Source_Unit + (Library_Unit (Item)))); + + Unitl : constant License_Type := + License (Source_Index (Current_Sem_Unit)); + + procedure License_Error; + -- Signal error of bad license + + ------------------- + -- License_Error -- + ------------------- + + procedure License_Error is + begin + Error_Msg_N + ("?license of with'ed unit & is incompatible", + Name (Item)); + end License_Error; + + -- Start of processing for License_Check + + begin + case Unitl is + when Unknown => + null; + + when Restricted => + if Withl = GPL then + License_Error; + end if; + + when GPL => + if Withl = Restricted then + License_Error; + end if; + + when Modified_GPL => + if Withl = Restricted or else Withl = GPL then + License_Error; + end if; + + when Unrestricted => + null; + end case; + end License_Check; + end if; + + -- Case of USE PACKAGE clause + + elsif Nkind (Item) = N_Use_Package_Clause then + Analyze_Use_Package (Item); + + -- Case of USE TYPE clause + + elsif Nkind (Item) = N_Use_Type_Clause then + Analyze_Use_Type (Item); + + -- Case of WITH TYPE clause + + -- A With_Type_Clause is processed when installing the context, + -- because it is a visibility mechanism and does not create a + -- semantic dependence on other units, as a With_Clause does. + + elsif Nkind (Item) = N_With_Type_Clause then + Analyze_With_Type_Clause (Item); + + -- case of PRAGMA + + elsif Nkind (Item) = N_Pragma then + Analyze (Item); + end if; + + <<Continue>> + Next (Item); + end loop; + + if Is_Child_Spec (Lib_Unit) then + + -- The unit also has implicit withs on its own parents. + + if No (Context_Items (N)) then + Set_Context_Items (N, New_List); + end if; + + Implicit_With_On_Parent (Lib_Unit, N); + end if; + + -- If the unit is a body, the context of the specification must also + -- be installed. + + if Nkind (Lib_Unit) = N_Package_Body + or else (Nkind (Lib_Unit) = N_Subprogram_Body + and then not Acts_As_Spec (N)) + then + Install_Context (Library_Unit (N)); + + if Is_Child_Spec (Unit (Library_Unit (N))) then + + -- If the unit is the body of a public child unit, the private + -- declarations of the parent must be made visible. If the child + -- unit is private, the private declarations have been installed + -- already in the call to Install_Parents for the spec. Installing + -- private declarations must be done for all ancestors of public + -- child units. In addition, sibling units mentioned in the + -- context clause of the body are directly visible. + + declare + Lib_Spec : Node_Id := Unit (Library_Unit (N)); + P : Node_Id; + P_Name : Entity_Id; + + begin + while Is_Child_Spec (Lib_Spec) loop + P := Unit (Parent_Spec (Lib_Spec)); + + if not (Private_Present (Parent (Lib_Spec))) then + P_Name := Defining_Entity (P); + Install_Private_Declarations (P_Name); + Set_Use (Private_Declarations (Specification (P))); + end if; + + Lib_Spec := P; + end loop; + end; + end if; + + -- For a package body, children in context are immediately visible + + Install_Siblings (Defining_Entity (Unit (Library_Unit (N))), N); + end if; + + if Nkind (Lib_Unit) = N_Generic_Package_Declaration + or else Nkind (Lib_Unit) = N_Generic_Subprogram_Declaration + or else Nkind (Lib_Unit) = N_Package_Declaration + or else Nkind (Lib_Unit) = N_Subprogram_Declaration + then + if Is_Child_Spec (Lib_Unit) then + Lib_Parent := Defining_Entity (Unit (Parent_Spec (Lib_Unit))); + Set_Is_Private_Descendant + (Defining_Entity (Lib_Unit), + Is_Private_Descendant (Lib_Parent) + or else Private_Present (Parent (Lib_Unit))); + + else + Set_Is_Private_Descendant + (Defining_Entity (Lib_Unit), + Private_Present (Parent (Lib_Unit))); + end if; + end if; + + if Check_Private then + Check_Private_Child_Unit (N); + end if; + end Install_Context_Clauses; + + --------------------- + -- Install_Parents -- + --------------------- + + procedure Install_Parents (Lib_Unit : Node_Id; Is_Private : Boolean) is + P : Node_Id; + E_Name : Entity_Id; + P_Name : Entity_Id; + P_Spec : Node_Id; + + begin + P := Unit (Parent_Spec (Lib_Unit)); + P_Name := Defining_Entity (P); + + if Etype (P_Name) = Any_Type then + return; + end if; + + if Ekind (P_Name) = E_Generic_Package + and then Nkind (Lib_Unit) /= N_Generic_Subprogram_Declaration + and then Nkind (Lib_Unit) /= N_Generic_Package_Declaration + and then Nkind (Lib_Unit) not in N_Generic_Renaming_Declaration + then + Error_Msg_N + ("child of a generic package must be a generic unit", Lib_Unit); + + elsif not Is_Package (P_Name) then + Error_Msg_N + ("parent unit must be package or generic package", Lib_Unit); + raise Unrecoverable_Error; + + elsif Present (Renamed_Object (P_Name)) then + Error_Msg_N ("parent unit cannot be a renaming", Lib_Unit); + raise Unrecoverable_Error; + + -- Verify that a child of an instance is itself an instance, or + -- the renaming of one. Given that an instance that is a unit is + -- replaced with a package declaration, check against the original + -- node. + + elsif Nkind (Original_Node (P)) = N_Package_Instantiation + and then Nkind (Lib_Unit) + not in N_Renaming_Declaration + and then Nkind (Original_Node (Lib_Unit)) + not in N_Generic_Instantiation + then + Error_Msg_N + ("child of an instance must be an instance or renaming", Lib_Unit); + end if; + + -- This is the recursive call that ensures all parents are loaded + + if Is_Child_Spec (P) then + Install_Parents (P, + Is_Private or else Private_Present (Parent (Lib_Unit))); + end if; + + -- Now we can install the context for this parent + + Install_Context_Clauses (Parent_Spec (Lib_Unit)); + Install_Siblings (P_Name, Parent (Lib_Unit)); + + -- The child unit is in the declarative region of the parent. The + -- parent must therefore appear in the scope stack and be visible, + -- as when compiling the corresponding body. If the child unit is + -- private or it is a package body, private declarations must be + -- accessible as well. Use declarations in the parent must also + -- be installed. Finally, other child units of the same parent that + -- are in the context are immediately visible. + + -- Find entity for compilation unit, and set its private descendant + -- status as needed. + + E_Name := Defining_Entity (Lib_Unit); + + Set_Is_Child_Unit (E_Name); + + Set_Is_Private_Descendant (E_Name, + Is_Private_Descendant (P_Name) + or else Private_Present (Parent (Lib_Unit))); + + P_Spec := Specification (Unit_Declaration_Node (P_Name)); + New_Scope (P_Name); + + -- Save current visibility of unit + + Scope_Stack.Table (Scope_Stack.Last).Previous_Visibility := + Is_Immediately_Visible (P_Name); + Set_Is_Immediately_Visible (P_Name); + Install_Visible_Declarations (P_Name); + Set_Use (Visible_Declarations (P_Spec)); + + if Is_Private + or else Private_Present (Parent (Lib_Unit)) + then + Install_Private_Declarations (P_Name); + Set_Use (Private_Declarations (P_Spec)); + end if; + end Install_Parents; + + ---------------------- + -- Install_Siblings -- + ---------------------- + + procedure Install_Siblings (U_Name : Entity_Id; N : Node_Id) is + Item : Node_Id; + Id : Entity_Id; + Prev : Entity_Id; + + function Is_Ancestor (E : Entity_Id) return Boolean; + -- Determine whether the scope of a child unit is an ancestor of + -- the current unit. + -- Shouldn't this be somewhere more general ??? + + function Is_Ancestor (E : Entity_Id) return Boolean is + Par : Entity_Id; + + begin + Par := U_Name; + + while Present (Par) + and then Par /= Standard_Standard + loop + + if Par = E then + return True; + end if; + + Par := Scope (Par); + end loop; + + return False; + end Is_Ancestor; + + -- Start of processing for Install_Siblings + + begin + -- Iterate over explicit with clauses, and check whether the + -- scope of each entity is an ancestor of the current unit. + + Item := First (Context_Items (N)); + + while Present (Item) loop + + if Nkind (Item) = N_With_Clause + and then not Implicit_With (Item) + then + Id := Entity (Name (Item)); + + if Is_Child_Unit (Id) + and then Is_Ancestor (Scope (Id)) + then + Set_Is_Immediately_Visible (Id); + Prev := Current_Entity (Id); + + -- Check for the presence of another unit in the context, + -- that may be inadvertently hidden by the child. + + if Present (Prev) + and then Is_Immediately_Visible (Prev) + and then not Is_Child_Unit (Prev) + then + declare + Clause : Node_Id; + + begin + Clause := First (Context_Items (N)); + + while Present (Clause) loop + if Nkind (Clause) = N_With_Clause + and then Entity (Name (Clause)) = Prev + then + Error_Msg_NE + ("child unit& hides compilation unit " & + "with the same name?", + Name (Item), Id); + exit; + end if; + + Next (Clause); + end loop; + end; + end if; + + -- the With_Clause may be on a grand-child, which makes + -- the child immediately visible. + + elsif Is_Child_Unit (Scope (Id)) + and then Is_Ancestor (Scope (Scope (Id))) + then + Set_Is_Immediately_Visible (Scope (Id)); + end if; + end if; + + Next (Item); + end loop; + end Install_Siblings; + + ------------------------- + -- Install_Withed_Unit -- + ------------------------- + + procedure Install_Withed_Unit (With_Clause : Node_Id) is + Uname : constant Entity_Id := Entity (Name (With_Clause)); + P : constant Entity_Id := Scope (Uname); + + begin + -- We do not apply the restrictions to an internal unit unless + -- we are compiling the internal unit as a main unit. This check + -- is also skipped for dummy units (for missing packages). + + if Sloc (Uname) /= No_Location + and then (not Is_Internal_File_Name (Unit_File_Name (Current_Sem_Unit)) + or else Current_Sem_Unit = Main_Unit) + then + Check_Restricted_Unit + (Unit_Name (Get_Source_Unit (Uname)), With_Clause); + end if; + + if P /= Standard_Standard then + + -- If the unit is not analyzed after analysis of the with clause, + -- and it is an instantiation, then it awaits a body and is the main + -- unit. Its appearance in the context of some other unit indicates + -- a circular dependency (DEC suite perversity). + + if not Analyzed (Uname) + and then Nkind (Parent (Uname)) = N_Package_Instantiation + then + Error_Msg_N + ("instantiation depends on itself", Name (With_Clause)); + + elsif not Is_Visible_Child_Unit (Uname) then + Set_Is_Visible_Child_Unit (Uname); + + if Is_Generic_Instance (Uname) + and then Ekind (Uname) in Subprogram_Kind + then + -- Set flag as well on the visible entity that denotes the + -- instance, which renames the current one. + + Set_Is_Visible_Child_Unit + (Related_Instance + (Defining_Entity (Unit (Library_Unit (With_Clause))))); + null; + end if; + + -- The parent unit may have been installed already, and + -- may have appeared in a use clause. + + if In_Use (Scope (Uname)) then + Set_Is_Potentially_Use_Visible (Uname); + end if; + + Set_Context_Installed (With_Clause); + end if; + + elsif not Is_Immediately_Visible (Uname) then + Set_Is_Immediately_Visible (Uname); + Set_Context_Installed (With_Clause); + end if; + + -- A with-clause overrides a with-type clause: there are no restric- + -- tions on the use of package entities. + + if Ekind (Uname) = E_Package then + Set_From_With_Type (Uname, False); + end if; + end Install_Withed_Unit; + + ------------------- + -- Is_Child_Spec -- + ------------------- + + function Is_Child_Spec (Lib_Unit : Node_Id) return Boolean is + K : constant Node_Kind := Nkind (Lib_Unit); + + begin + return (K in N_Generic_Declaration or else + K in N_Generic_Instantiation or else + K in N_Generic_Renaming_Declaration or else + K = N_Package_Declaration or else + K = N_Package_Renaming_Declaration or else + K = N_Subprogram_Declaration or else + K = N_Subprogram_Renaming_Declaration) + and then Present (Parent_Spec (Lib_Unit)); + end Is_Child_Spec; + + ----------------------- + -- Load_Needed_Body -- + ----------------------- + + -- N is a generic unit named in a with clause, or else it is + -- a unit that contains a generic unit or an inlined function. + -- In order to perform an instantiation, the body of the unit + -- must be present. If the unit itself is generic, we assume + -- that an instantiation follows, and load and analyze the body + -- unconditionally. This forces analysis of the spec as well. + + -- If the unit is not generic, but contains a generic unit, it + -- is loaded on demand, at the point of instantiation (see ch12). + + procedure Load_Needed_Body (N : Node_Id; OK : out Boolean) is + Body_Name : Unit_Name_Type; + Unum : Unit_Number_Type; + + Save_Style_Check : constant Boolean := Opt.Style_Check; + -- The loading and analysis is done with style checks off + + begin + if not GNAT_Mode then + Style_Check := False; + end if; + + Body_Name := Get_Body_Name (Get_Unit_Name (Unit (N))); + Unum := + Load_Unit + (Load_Name => Body_Name, + Required => False, + Subunit => False, + Error_Node => N, + Renamings => True); + + if Unum = No_Unit then + OK := False; + + else + Compiler_State := Analyzing; -- reset after load + + if not Fatal_Error (Unum) then + if Debug_Flag_L then + Write_Str ("*** Loaded generic body"); + Write_Eol; + end if; + + Semantics (Cunit (Unum)); + end if; + + OK := True; + end if; + + Style_Check := Save_Style_Check; + end Load_Needed_Body; + + -------------------- + -- Remove_Context -- + -------------------- + + procedure Remove_Context (N : Node_Id) is + Lib_Unit : constant Node_Id := Unit (N); + + begin + -- If this is a child unit, first remove the parent units. + + if Is_Child_Spec (Lib_Unit) then + Remove_Parents (Lib_Unit); + end if; + + Remove_Context_Clauses (N); + end Remove_Context; + + ---------------------------- + -- Remove_Context_Clauses -- + ---------------------------- + + procedure Remove_Context_Clauses (N : Node_Id) is + Item : Node_Id; + Unit_Name : Entity_Id; + + begin + + -- Loop through context items and undo with_clauses and use_clauses. + + Item := First (Context_Items (N)); + + while Present (Item) loop + + -- We are interested only in with clauses which got installed + -- on entry, as indicated by their Context_Installed flag set + + if Nkind (Item) = N_With_Clause + and then Context_Installed (Item) + then + -- Remove items from one with'ed unit + + Unit_Name := Entity (Name (Item)); + Remove_Unit_From_Visibility (Unit_Name); + Set_Context_Installed (Item, False); + + elsif Nkind (Item) = N_Use_Package_Clause then + End_Use_Package (Item); + + elsif Nkind (Item) = N_Use_Type_Clause then + End_Use_Type (Item); + + elsif Nkind (Item) = N_With_Type_Clause then + Remove_With_Type_Clause (Name (Item)); + end if; + + Next (Item); + end loop; + + end Remove_Context_Clauses; + + -------------------- + -- Remove_Parents -- + -------------------- + + procedure Remove_Parents (Lib_Unit : Node_Id) is + P : Node_Id; + P_Name : Entity_Id; + E : Entity_Id; + Vis : constant Boolean := + Scope_Stack.Table (Scope_Stack.Last).Previous_Visibility; + + begin + if Is_Child_Spec (Lib_Unit) then + P := Unit (Parent_Spec (Lib_Unit)); + P_Name := Defining_Entity (P); + + Remove_Context_Clauses (Parent_Spec (Lib_Unit)); + End_Package_Scope (P_Name); + Set_Is_Immediately_Visible (P_Name, Vis); + + -- Remove from visibility the siblings as well, which are directly + -- visible while the parent is in scope. + + E := First_Entity (P_Name); + + while Present (E) loop + + if Is_Child_Unit (E) then + Set_Is_Immediately_Visible (E, False); + end if; + + Next_Entity (E); + end loop; + + Set_In_Package_Body (P_Name, False); + + -- This is the recursive call to remove the context of any + -- higher level parent. This recursion ensures that all parents + -- are removed in the reverse order of their installation. + + Remove_Parents (P); + end if; + end Remove_Parents; + + ----------------------------- + -- Remove_With_Type_Clause -- + ----------------------------- + + procedure Remove_With_Type_Clause (Name : Node_Id) is + Typ : Entity_Id; + P : Entity_Id; + + procedure Unchain (E : Entity_Id); + -- Remove entity from visibility list. + + procedure Unchain (E : Entity_Id) is + Prev : Entity_Id; + + begin + Prev := Current_Entity (E); + + -- Package entity may appear is several with_type_clauses, and + -- may have been removed already. + + if No (Prev) then + return; + + elsif Prev = E then + Set_Name_Entity_Id (Chars (E), Homonym (E)); + + else + while Present (Prev) + and then Homonym (Prev) /= E + loop + Prev := Homonym (Prev); + end loop; + + if (Present (Prev)) then + Set_Homonym (Prev, Homonym (E)); + end if; + end if; + end Unchain; + + begin + if Nkind (Name) = N_Selected_Component then + Typ := Entity (Selector_Name (Name)); + + if No (Typ) then -- error in declaration. + return; + end if; + else + return; + end if; + + P := Scope (Typ); + + -- If the exporting package has been analyzed, it has appeared in the + -- context already and should be left alone. Otherwise, remove from + -- visibility. + + if not Analyzed (Unit_Declaration_Node (P)) then + Unchain (P); + Unchain (Typ); + Set_Is_Frozen (Typ, False); + end if; + + if Ekind (Typ) = E_Record_Type then + Set_From_With_Type (Class_Wide_Type (Typ), False); + Set_From_With_Type (Typ, False); + end if; + + Set_From_With_Type (P, False); + + -- If P is a child unit, remove parents as well. + + P := Scope (P); + + while Present (P) + and then P /= Standard_Standard + loop + Set_From_With_Type (P, False); + + if not Analyzed (Unit_Declaration_Node (P)) then + Unchain (P); + end if; + + P := Scope (P); + end loop; + + -- The back-end needs to know that an access type is imported, so it + -- does not need elaboration and can appear in a mutually recursive + -- record definition, so the imported flag on an access type is + -- preserved. + + end Remove_With_Type_Clause; + + --------------------------------- + -- Remove_Unit_From_Visibility -- + --------------------------------- + + procedure Remove_Unit_From_Visibility (Unit_Name : Entity_Id) is + P : Entity_Id := Scope (Unit_Name); + + begin + + if Debug_Flag_I then + Write_Str ("remove withed unit "); + Write_Name (Chars (Unit_Name)); + Write_Eol; + end if; + + if P /= Standard_Standard then + Set_Is_Visible_Child_Unit (Unit_Name, False); + end if; + + Set_Is_Potentially_Use_Visible (Unit_Name, False); + Set_Is_Immediately_Visible (Unit_Name, False); + + end Remove_Unit_From_Visibility; + +end Sem_Ch10; |