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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M . C H 7 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2011, 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. -- -- -- ------------------------------------------------------------------------------ -- This package contains the routines to process package specifications and -- bodies. The most important semantic aspects of package processing are the -- handling of private and full declarations, and the construction of dispatch -- tables for tagged types. with Atree; use Atree; with Debug; use Debug; with Einfo; use Einfo; with Elists; use Elists; with Errout; use Errout; with Exp_Disp; use Exp_Disp; with Exp_Dist; use Exp_Dist; with Exp_Dbug; use Exp_Dbug; with Lib; use Lib; with Lib.Xref; use Lib.Xref; with Namet; use Namet; with Nmake; use Nmake; with Nlists; use Nlists; with Opt; use Opt; with Output; use Output; with Restrict; use Restrict; with Sem; use Sem; with Sem_Aux; use Sem_Aux; with Sem_Cat; use Sem_Cat; with Sem_Ch3; use Sem_Ch3; with Sem_Ch6; use Sem_Ch6; with Sem_Ch8; use Sem_Ch8; with Sem_Ch10; use Sem_Ch10; with Sem_Ch12; use Sem_Ch12; with Sem_Ch13; use Sem_Ch13; with Sem_Disp; use Sem_Disp; with Sem_Eval; use Sem_Eval; with Sem_Util; use Sem_Util; with Sem_Warn; use Sem_Warn; with Snames; use Snames; with Stand; use Stand; with Sinfo; use Sinfo; with Sinput; use Sinput; with Style; with Uintp; use Uintp; package body Sem_Ch7 is ----------------------------------- -- Handling private declarations -- ----------------------------------- -- The principle that each entity has a single defining occurrence clashes -- with the presence of two separate definitions for private types: the -- first is the private type declaration, and the second is the full type -- declaration. It is important that all references to the type point to -- the same defining occurrence, namely the first one. To enforce the two -- separate views of the entity, the corresponding information is swapped -- between the two declarations. Outside of the package, the defining -- occurrence only contains the private declaration information, while in -- the private part and the body of the package the defining occurrence -- contains the full declaration. To simplify the swap, the defining -- occurrence that currently holds the private declaration points to the -- full declaration. During semantic processing the defining occurrence -- also points to a list of private dependents, that is to say access types -- or composite types whose designated types or component types are -- subtypes or derived types of the private type in question. After the -- full declaration has been seen, the private dependents are updated to -- indicate that they have full definitions. ----------------------- -- Local Subprograms -- ----------------------- procedure Analyze_Package_Body_Helper (N : Node_Id); -- Does all the real work of Analyze_Package_Body procedure Check_Anonymous_Access_Types (Spec_Id : Entity_Id; P_Body : Node_Id); -- If the spec of a package has a limited_with_clause, it may declare -- anonymous access types whose designated type is a limited view, such an -- anonymous access return type for a function. This access type cannot be -- elaborated in the spec itself, but it may need an itype reference if it -- is used within a nested scope. In that case the itype reference is -- created at the beginning of the corresponding package body and inserted -- before other body declarations. procedure Install_Package_Entity (Id : Entity_Id); -- Supporting procedure for Install_{Visible,Private}_Declarations. Places -- one entity on its visibility chain, and recurses on the visible part if -- the entity is an inner package. function Is_Private_Base_Type (E : Entity_Id) return Boolean; -- True for a private type that is not a subtype function Is_Visible_Dependent (Dep : Entity_Id) return Boolean; -- If the private dependent is a private type whose full view is derived -- from the parent type, its full properties are revealed only if we are in -- the immediate scope of the private dependent. Should this predicate be -- tightened further??? procedure Declare_Inherited_Private_Subprograms (Id : Entity_Id); -- Called upon entering the private part of a public child package and the -- body of a nested package, to potentially declare certain inherited -- subprograms that were inherited by types in the visible part, but whose -- declaration was deferred because the parent operation was private and -- not visible at that point. These subprograms are located by traversing -- the visible part declarations looking for non-private type extensions -- and then examining each of the primitive operations of such types to -- find those that were inherited but declared with a special internal -- name. Each such operation is now declared as an operation with a normal -- name (using the name of the parent operation) and replaces the previous -- implicit operation in the primitive operations list of the type. If the -- inherited private operation has been overridden, then it's replaced by -- the overriding operation. -------------------------- -- Analyze_Package_Body -- -------------------------- procedure Analyze_Package_Body (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); begin if Debug_Flag_C then Write_Str ("==> package body "); Write_Name (Chars (Defining_Entity (N))); Write_Str (" from "); Write_Location (Loc); Write_Eol; Indent; end if; -- The real work is split out into the helper, so it can do "return;" -- without skipping the debug output. Analyze_Package_Body_Helper (N); if Debug_Flag_C then Outdent; Write_Str ("<== package body "); Write_Name (Chars (Defining_Entity (N))); Write_Str (" from "); Write_Location (Loc); Write_Eol; end if; end Analyze_Package_Body; --------------------------------- -- Analyze_Package_Body_Helper -- --------------------------------- procedure Analyze_Package_Body_Helper (N : Node_Id) is HSS : Node_Id; Body_Id : Entity_Id; Spec_Id : Entity_Id; Last_Spec_Entity : Entity_Id; New_N : Node_Id; Pack_Decl : Node_Id; procedure Install_Composite_Operations (P : Entity_Id); -- Composite types declared in the current scope may depend on types -- that were private at the point of declaration, and whose full view -- is now in scope. Indicate that the corresponding operations on the -- composite type are available. ---------------------------------- -- Install_Composite_Operations -- ---------------------------------- procedure Install_Composite_Operations (P : Entity_Id) is Id : Entity_Id; begin Id := First_Entity (P); while Present (Id) loop if Is_Type (Id) and then (Is_Limited_Composite (Id) or else Is_Private_Composite (Id)) and then No (Private_Component (Id)) then Set_Is_Limited_Composite (Id, False); Set_Is_Private_Composite (Id, False); end if; Next_Entity (Id); end loop; end Install_Composite_Operations; -- Start of processing for Analyze_Package_Body_Helper begin -- Find corresponding package specification, and establish the current -- scope. The visible defining entity for the package is the defining -- occurrence in the spec. On exit from the package body, all body -- declarations are attached to the defining entity for the body, but -- the later is never used for name resolution. In this fashion there -- is only one visible entity that denotes the package. -- Set Body_Id. Note that this Will be reset to point to the generic -- copy later on in the generic case. Body_Id := Defining_Entity (N); if Present (Corresponding_Spec (N)) then -- Body is body of package instantiation. Corresponding spec has -- already been set. Spec_Id := Corresponding_Spec (N); Pack_Decl := Unit_Declaration_Node (Spec_Id); else Spec_Id := Current_Entity_In_Scope (Defining_Entity (N)); if Present (Spec_Id) and then Is_Package_Or_Generic_Package (Spec_Id) then Pack_Decl := Unit_Declaration_Node (Spec_Id); if Nkind (Pack_Decl) = N_Package_Renaming_Declaration then Error_Msg_N ("cannot supply body for package renaming", N); return; elsif Present (Corresponding_Body (Pack_Decl)) then Error_Msg_N ("redefinition of package body", N); return; end if; else Error_Msg_N ("missing specification for package body", N); return; end if; if Is_Package_Or_Generic_Package (Spec_Id) and then (Scope (Spec_Id) = Standard_Standard or else Is_Child_Unit (Spec_Id)) and then not Unit_Requires_Body (Spec_Id) then if Ada_Version = Ada_83 then Error_Msg_N ("optional package body (not allowed in Ada 95)?", N); else Error_Msg_N ("spec of this package does not allow a body", N); end if; end if; end if; Set_Is_Compilation_Unit (Body_Id, Is_Compilation_Unit (Spec_Id)); Style.Check_Identifier (Body_Id, Spec_Id); if Is_Child_Unit (Spec_Id) then if Nkind (Parent (N)) /= N_Compilation_Unit then Error_Msg_NE ("body of child unit& cannot be an inner package", N, Spec_Id); end if; Set_Is_Child_Unit (Body_Id); end if; -- Generic package case if Ekind (Spec_Id) = E_Generic_Package then -- Disable expansion and perform semantic analysis on copy. The -- unannotated body will be used in all instantiations. Body_Id := Defining_Entity (N); Set_Ekind (Body_Id, E_Package_Body); Set_Scope (Body_Id, Scope (Spec_Id)); Set_Is_Obsolescent (Body_Id, Is_Obsolescent (Spec_Id)); Set_Body_Entity (Spec_Id, Body_Id); Set_Spec_Entity (Body_Id, Spec_Id); New_N := Copy_Generic_Node (N, Empty, Instantiating => False); Rewrite (N, New_N); -- Update Body_Id to point to the copied node for the remainder of -- the processing. Body_Id := Defining_Entity (N); Start_Generic; end if; -- The Body_Id is that of the copied node in the generic case, the -- current node otherwise. Note that N was rewritten above, so we must -- be sure to get the latest Body_Id value. Set_Ekind (Body_Id, E_Package_Body); Set_Body_Entity (Spec_Id, Body_Id); Set_Spec_Entity (Body_Id, Spec_Id); -- Defining name for the package body is not a visible entity: Only the -- defining name for the declaration is visible. Set_Etype (Body_Id, Standard_Void_Type); Set_Scope (Body_Id, Scope (Spec_Id)); Set_Corresponding_Spec (N, Spec_Id); Set_Corresponding_Body (Pack_Decl, Body_Id); -- The body entity is not used for semantics or code generation, but -- it is attached to the entity list of the enclosing scope to simplify -- the listing of back-annotations for the types it main contain. if Scope (Spec_Id) /= Standard_Standard then Append_Entity (Body_Id, Scope (Spec_Id)); end if; -- Indicate that we are currently compiling the body of the package Set_In_Package_Body (Spec_Id); Set_Has_Completion (Spec_Id); Last_Spec_Entity := Last_Entity (Spec_Id); Push_Scope (Spec_Id); Set_Categorization_From_Pragmas (N); Install_Visible_Declarations (Spec_Id); Install_Private_Declarations (Spec_Id); Install_Private_With_Clauses (Spec_Id); Install_Composite_Operations (Spec_Id); Check_Anonymous_Access_Types (Spec_Id, N); if Ekind (Spec_Id) = E_Generic_Package then Set_Use (Generic_Formal_Declarations (Pack_Decl)); end if; Set_Use (Visible_Declarations (Specification (Pack_Decl))); Set_Use (Private_Declarations (Specification (Pack_Decl))); -- This is a nested package, so it may be necessary to declare certain -- inherited subprograms that are not yet visible because the parent -- type's subprograms are now visible. if Ekind (Scope (Spec_Id)) = E_Package and then Scope (Spec_Id) /= Standard_Standard then Declare_Inherited_Private_Subprograms (Spec_Id); end if; if Present (Declarations (N)) then Analyze_Declarations (Declarations (N)); Inspect_Deferred_Constant_Completion (Declarations (N)); end if; -- Analyze_Declarations has caused freezing of all types. Now generate -- bodies for RACW primitives and stream attributes, if any. if Ekind (Spec_Id) = E_Package and then Has_RACW (Spec_Id) then -- Attach subprogram bodies to support RACWs declared in spec Append_RACW_Bodies (Declarations (N), Spec_Id); Analyze_List (Declarations (N)); end if; HSS := Handled_Statement_Sequence (N); if Present (HSS) then Process_End_Label (HSS, 't', Spec_Id); Analyze (HSS); -- Check that elaboration code in a preelaborable package body is -- empty other than null statements and labels (RM 10.2.1(6)). Validate_Null_Statement_Sequence (N); end if; Validate_Categorization_Dependency (N, Spec_Id); Check_Completion (Body_Id); -- Generate start of body reference. Note that we do this fairly late, -- because the call will use In_Extended_Main_Source_Unit as a check, -- and we want to make sure that Corresponding_Stub links are set Generate_Reference (Spec_Id, Body_Id, 'b', Set_Ref => False); -- For a generic package, collect global references and mark them on -- the original body so that they are not resolved again at the point -- of instantiation. if Ekind (Spec_Id) /= E_Package then Save_Global_References (Original_Node (N)); End_Generic; end if; -- The entities of the package body have so far been chained onto the -- declaration chain for the spec. That's been fine while we were in the -- body, since we wanted them to be visible, but now that we are leaving -- the package body, they are no longer visible, so we remove them from -- the entity chain of the package spec entity, and copy them to the -- entity chain of the package body entity, where they will never again -- be visible. if Present (Last_Spec_Entity) then Set_First_Entity (Body_Id, Next_Entity (Last_Spec_Entity)); Set_Next_Entity (Last_Spec_Entity, Empty); Set_Last_Entity (Body_Id, Last_Entity (Spec_Id)); Set_Last_Entity (Spec_Id, Last_Spec_Entity); else Set_First_Entity (Body_Id, First_Entity (Spec_Id)); Set_Last_Entity (Body_Id, Last_Entity (Spec_Id)); Set_First_Entity (Spec_Id, Empty); Set_Last_Entity (Spec_Id, Empty); end if; End_Package_Scope (Spec_Id); -- All entities declared in body are not visible declare E : Entity_Id; begin E := First_Entity (Body_Id); while Present (E) loop Set_Is_Immediately_Visible (E, False); Set_Is_Potentially_Use_Visible (E, False); Set_Is_Hidden (E); -- Child units may appear on the entity list (e.g. if they appear -- in the context of a subunit) but they are not body entities. if not Is_Child_Unit (E) then Set_Is_Package_Body_Entity (E); end if; Next_Entity (E); end loop; end; Check_References (Body_Id); -- For a generic unit, check that the formal parameters are referenced, -- and that local variables are used, as for regular packages. if Ekind (Spec_Id) = E_Generic_Package then Check_References (Spec_Id); end if; -- The processing so far has made all entities of the package body -- public (i.e. externally visible to the linker). This is in general -- necessary, since inlined or generic bodies, for which code is -- generated in other units, may need to see these entities. The -- following loop runs backwards from the end of the entities of the -- package body making these entities invisible until we reach a -- referencer, i.e. a declaration that could reference a previous -- declaration, a generic body or an inlined body, or a stub (which may -- contain either of these). This is of course an approximation, but it -- is conservative and definitely correct. -- We only do this at the outer (library) level non-generic packages. -- The reason is simply to cut down on the number of global symbols -- generated, which has a double effect: (1) to make the compilation -- process more efficient and (2) to give the code generator more -- freedom to optimize within each unit, especially subprograms. if (Scope (Spec_Id) = Standard_Standard or else Is_Child_Unit (Spec_Id)) and then not Is_Generic_Unit (Spec_Id) and then Present (Declarations (N)) then Make_Non_Public_Where_Possible : declare function Has_Referencer (L : List_Id; Outer : Boolean) return Boolean; -- Traverse the given list of declarations in reverse order. -- Return True if a referencer is present. Return False if none is -- found. The Outer parameter is True for the outer level call and -- False for inner level calls for nested packages. If Outer is -- True, then any entities up to the point of hitting a referencer -- get their Is_Public flag cleared, so that the entities will be -- treated as static entities in the C sense, and need not have -- fully qualified names. Furthermore, if the referencer is an -- inlined subprogram that doesn't reference other subprograms, -- we keep clearing the Is_Public flag on subprograms. For inner -- levels, we need all names to be fully qualified to deal with -- the same name appearing in parallel packages (right now this -- is tied to their being external). -------------------- -- Has_Referencer -- -------------------- function Has_Referencer (L : List_Id; Outer : Boolean) return Boolean is Has_Referencer_Except_For_Subprograms : Boolean := False; D : Node_Id; E : Entity_Id; K : Node_Kind; S : Entity_Id; function Check_Subprogram_Ref (N : Node_Id) return Traverse_Result; -- Look for references to subprograms -------------------------- -- Check_Subprogram_Ref -- -------------------------- function Check_Subprogram_Ref (N : Node_Id) return Traverse_Result is V : Node_Id; begin -- Check name of procedure or function calls if Nkind_In (N, N_Procedure_Call_Statement, N_Function_Call) and then Is_Entity_Name (Name (N)) then return Abandon; end if; -- Check prefix of attribute references if Nkind (N) = N_Attribute_Reference and then Is_Entity_Name (Prefix (N)) and then Present (Entity (Prefix (N))) and then Ekind (Entity (Prefix (N))) in Subprogram_Kind then return Abandon; end if; -- Check value of constants if Nkind (N) = N_Identifier and then Present (Entity (N)) and then Ekind (Entity (N)) = E_Constant then V := Constant_Value (Entity (N)); if Present (V) and then not Compile_Time_Known_Value_Or_Aggr (V) then return Abandon; end if; end if; return OK; end Check_Subprogram_Ref; function Check_Subprogram_Refs is new Traverse_Func (Check_Subprogram_Ref); -- Start of processing for Has_Referencer begin if No (L) then return False; end if; D := Last (L); while Present (D) loop K := Nkind (D); if K in N_Body_Stub then return True; -- Processing for subprogram bodies elsif K = N_Subprogram_Body then if Acts_As_Spec (D) then E := Defining_Entity (D); -- An inlined body acts as a referencer. Note also -- that we never reset Is_Public for an inlined -- subprogram. Gigi requires Is_Public to be set. -- Note that we test Has_Pragma_Inline here rather -- than Is_Inlined. We are compiling this for a -- client, and it is the client who will decide if -- actual inlining should occur, so we need to assume -- that the procedure could be inlined for the purpose -- of accessing global entities. if Has_Pragma_Inline (E) then if Outer and then Check_Subprogram_Refs (D) = OK then Has_Referencer_Except_For_Subprograms := True; else return True; end if; else Set_Is_Public (E, False); end if; else E := Corresponding_Spec (D); if Present (E) then -- A generic subprogram body acts as a referencer if Is_Generic_Unit (E) then return True; end if; if Has_Pragma_Inline (E) or else Is_Inlined (E) then if Outer and then Check_Subprogram_Refs (D) = OK then Has_Referencer_Except_For_Subprograms := True; else return True; end if; end if; end if; end if; -- Processing for package bodies elsif K = N_Package_Body and then Present (Corresponding_Spec (D)) then E := Corresponding_Spec (D); -- Generic package body is a referencer. It would seem -- that we only have to consider generics that can be -- exported, i.e. where the corresponding spec is the -- spec of the current package, but because of nested -- instantiations, a fully private generic body may -- export other private body entities. Furthermore, -- regardless of whether there was a previous inlined -- subprogram, (an instantiation of) the generic package -- may reference any entity declared before it. if Is_Generic_Unit (E) then return True; -- For non-generic package body, recurse into body unless -- this is an instance, we ignore instances since they -- cannot have references that affect outer entities. elsif not Is_Generic_Instance (E) and then not Has_Referencer_Except_For_Subprograms then if Has_Referencer (Declarations (D), Outer => False) then return True; end if; end if; -- Processing for package specs, recurse into declarations. -- Again we skip this for the case of generic instances. elsif K = N_Package_Declaration and then not Has_Referencer_Except_For_Subprograms then S := Specification (D); if not Is_Generic_Unit (Defining_Entity (S)) then if Has_Referencer (Private_Declarations (S), Outer => False) then return True; elsif Has_Referencer (Visible_Declarations (S), Outer => False) then return True; end if; end if; -- Objects and exceptions need not be public if we have not -- encountered a referencer so far. We only reset the flag -- for outer level entities that are not imported/exported, -- and which have no interface name. elsif Nkind_In (K, N_Object_Declaration, N_Exception_Declaration, N_Subprogram_Declaration) then E := Defining_Entity (D); if Outer and then (not Has_Referencer_Except_For_Subprograms or else K = N_Subprogram_Declaration) and then not Is_Imported (E) and then not Is_Exported (E) and then No (Interface_Name (E)) then Set_Is_Public (E, False); end if; end if; Prev (D); end loop; return Has_Referencer_Except_For_Subprograms; end Has_Referencer; -- Start of processing for Make_Non_Public_Where_Possible begin declare Discard : Boolean; pragma Warnings (Off, Discard); begin Discard := Has_Referencer (Declarations (N), Outer => True); end; end Make_Non_Public_Where_Possible; end if; -- If expander is not active, then here is where we turn off the -- In_Package_Body flag, otherwise it is turned off at the end of the -- corresponding expansion routine. If this is an instance body, we need -- to qualify names of local entities, because the body may have been -- compiled as a preliminary to another instantiation. if not Expander_Active then Set_In_Package_Body (Spec_Id, False); if Is_Generic_Instance (Spec_Id) and then Operating_Mode = Generate_Code then Qualify_Entity_Names (N); end if; end if; end Analyze_Package_Body_Helper; --------------------------------- -- Analyze_Package_Declaration -- --------------------------------- procedure Analyze_Package_Declaration (N : Node_Id) is Id : constant Node_Id := Defining_Entity (N); PF : Boolean; -- True when in the context of a declared pure library unit Body_Required : Boolean; -- True when this package declaration requires a corresponding body Comp_Unit : Boolean; -- True when this package declaration is not a nested declaration begin -- Analye aspect specifications immediately, since we need to recognize -- things like Pure early enough to diagnose violations during analysis. if Has_Aspects (N) then Analyze_Aspect_Specifications (N, Id); end if; -- Ada 2005 (AI-217): Check if the package has been erroneously named -- in a limited-with clause of its own context. In this case the error -- has been previously notified by Analyze_Context. -- limited with Pkg; -- ERROR -- package Pkg is ... if From_With_Type (Id) then return; end if; if Debug_Flag_C then Write_Str ("==> package spec "); Write_Name (Chars (Id)); Write_Str (" from "); Write_Location (Sloc (N)); Write_Eol; Indent; end if; Generate_Definition (Id); Enter_Name (Id); Set_Ekind (Id, E_Package); Set_Etype (Id, Standard_Void_Type); Push_Scope (Id); PF := Is_Pure (Enclosing_Lib_Unit_Entity); Set_Is_Pure (Id, PF); Set_Categorization_From_Pragmas (N); Analyze (Specification (N)); Validate_Categorization_Dependency (N, Id); Body_Required := Unit_Requires_Body (Id); -- When this spec does not require an explicit body, we know that there -- are no entities requiring completion in the language sense; we call -- Check_Completion here only to ensure that any nested package -- declaration that requires an implicit body gets one. (In the case -- where a body is required, Check_Completion is called at the end of -- the body's declarative part.) if not Body_Required then Check_Completion; end if; Comp_Unit := Nkind (Parent (N)) = N_Compilation_Unit; if Comp_Unit then -- Set Body_Required indication on the compilation unit node, and -- determine whether elaboration warnings may be meaningful on it. Set_Body_Required (Parent (N), Body_Required); if not Body_Required then Set_Suppress_Elaboration_Warnings (Id); end if; end if; End_Package_Scope (Id); -- For the declaration of a library unit that is a remote types package, -- check legality rules regarding availability of stream attributes for -- types that contain non-remote access values. This subprogram performs -- visibility tests that rely on the fact that we have exited the scope -- of Id. if Comp_Unit then Validate_RT_RAT_Component (N); end if; if Debug_Flag_C then Outdent; Write_Str ("<== package spec "); Write_Name (Chars (Id)); Write_Str (" from "); Write_Location (Sloc (N)); Write_Eol; end if; end Analyze_Package_Declaration; ----------------------------------- -- Analyze_Package_Specification -- ----------------------------------- -- Note that this code is shared for the analysis of generic package specs -- (see Sem_Ch12.Analyze_Generic_Package_Declaration for details). procedure Analyze_Package_Specification (N : Node_Id) is Id : constant Entity_Id := Defining_Entity (N); Orig_Decl : constant Node_Id := Original_Node (Parent (N)); Vis_Decls : constant List_Id := Visible_Declarations (N); Priv_Decls : constant List_Id := Private_Declarations (N); E : Entity_Id; L : Entity_Id; Public_Child : Boolean; Private_With_Clauses_Installed : Boolean := False; -- In Ada 2005, private with_clauses are visible in the private part -- of a nested package, even if it appears in the public part of the -- enclosing package. This requires a separate step to install these -- private_with_clauses, and remove them at the end of the nested -- package. procedure Check_One_Tagged_Type_Or_Extension_At_Most; -- Issue an error in SPARK mode if a package specification contains -- more than one tagged type or type extension. procedure Clear_Constants (Id : Entity_Id; FE : Entity_Id); -- Clears constant indications (Never_Set_In_Source, Constant_Value, and -- Is_True_Constant) on all variables that are entities of Id, and on -- the chain whose first element is FE. A recursive call is made for all -- packages and generic packages. procedure Generate_Parent_References; -- For a child unit, generate references to parent units, for -- GPS navigation purposes. function Is_Public_Child (Child, Unit : Entity_Id) return Boolean; -- Child and Unit are entities of compilation units. True if Child -- is a public child of Parent as defined in 10.1.1 procedure Inspect_Unchecked_Union_Completion (Decls : List_Id); -- Detects all incomplete or private type declarations having a known -- discriminant part that are completed by an Unchecked_Union. Emits -- the error message "Unchecked_Union may not complete discriminated -- partial view". procedure Install_Parent_Private_Declarations (Inst_Id : Entity_Id); -- Given the package entity of a generic package instantiation or -- formal package whose corresponding generic is a child unit, installs -- the private declarations of each of the child unit's parents. -- This has to be done at the point of entering the instance package's -- private part rather than being done in Sem_Ch12.Install_Parent -- (which is where the parents' visible declarations are installed). ------------------------------------------------ -- Check_One_Tagged_Type_Or_Extension_At_Most -- ------------------------------------------------ procedure Check_One_Tagged_Type_Or_Extension_At_Most is Previous : Node_Id; procedure Check_Decls (Decls : List_Id); -- Check that either Previous is Empty and Decls does not contain -- more than one tagged type or type extension, or Previous is -- already set and Decls contains no tagged type or type extension. ----------------- -- Check_Decls -- ----------------- procedure Check_Decls (Decls : List_Id) is Decl : Node_Id; begin Decl := First (Decls); while Present (Decl) loop if Nkind (Decl) = N_Full_Type_Declaration and then Is_Tagged_Type (Defining_Identifier (Decl)) then if No (Previous) then Previous := Decl; else Error_Msg_Sloc := Sloc (Previous); Check_SPARK_Restriction ("at most one tagged type or type extension allowed", "\\ previous declaration#", Decl); end if; end if; Next (Decl); end loop; end Check_Decls; -- Start of processing for Check_One_Tagged_Type_Or_Extension_At_Most begin Previous := Empty; Check_Decls (Vis_Decls); if Present (Priv_Decls) then Check_Decls (Priv_Decls); end if; end Check_One_Tagged_Type_Or_Extension_At_Most; --------------------- -- Clear_Constants -- --------------------- procedure Clear_Constants (Id : Entity_Id; FE : Entity_Id) is E : Entity_Id; begin -- Ignore package renamings, not interesting and they can cause self -- referential loops in the code below. if Nkind (Parent (Id)) = N_Package_Renaming_Declaration then return; end if; -- Note: in the loop below, the check for Next_Entity pointing back -- to the package entity may seem odd, but it is needed, because a -- package can contain a renaming declaration to itself, and such -- renamings are generated automatically within package instances. E := FE; while Present (E) and then E /= Id loop if Is_Assignable (E) then Set_Never_Set_In_Source (E, False); Set_Is_True_Constant (E, False); Set_Current_Value (E, Empty); Set_Is_Known_Null (E, False); Set_Last_Assignment (E, Empty); if not Can_Never_Be_Null (E) then Set_Is_Known_Non_Null (E, False); end if; elsif Is_Package_Or_Generic_Package (E) then Clear_Constants (E, First_Entity (E)); Clear_Constants (E, First_Private_Entity (E)); end if; Next_Entity (E); end loop; end Clear_Constants; -------------------------------- -- Generate_Parent_References -- -------------------------------- procedure Generate_Parent_References is Decl : constant Node_Id := Parent (N); begin if Id = Cunit_Entity (Main_Unit) or else Parent (Decl) = Library_Unit (Cunit (Main_Unit)) then Generate_Reference (Id, Scope (Id), 'k', False); elsif not Nkind_In (Unit (Cunit (Main_Unit)), N_Subprogram_Body, N_Subunit) then -- If current unit is an ancestor of main unit, generate a -- reference to its own parent. declare U : Node_Id; Main_Spec : Node_Id := Unit (Cunit (Main_Unit)); begin if Nkind (Main_Spec) = N_Package_Body then Main_Spec := Unit (Library_Unit (Cunit (Main_Unit))); end if; U := Parent_Spec (Main_Spec); while Present (U) loop if U = Parent (Decl) then Generate_Reference (Id, Scope (Id), 'k', False); exit; elsif Nkind (Unit (U)) = N_Package_Body then exit; else U := Parent_Spec (Unit (U)); end if; end loop; end; end if; end Generate_Parent_References; --------------------- -- Is_Public_Child -- --------------------- function Is_Public_Child (Child, Unit : Entity_Id) return Boolean is begin if not Is_Private_Descendant (Child) then return True; else if Child = Unit then return not Private_Present ( Parent (Unit_Declaration_Node (Child))); else return Is_Public_Child (Scope (Child), Unit); end if; end if; end Is_Public_Child; ---------------------------------------- -- Inspect_Unchecked_Union_Completion -- ---------------------------------------- procedure Inspect_Unchecked_Union_Completion (Decls : List_Id) is Decl : Node_Id; begin Decl := First (Decls); while Present (Decl) loop -- We are looking at an incomplete or private type declaration -- with a known_discriminant_part whose full view is an -- Unchecked_Union. if Nkind_In (Decl, N_Incomplete_Type_Declaration, N_Private_Type_Declaration) and then Has_Discriminants (Defining_Identifier (Decl)) and then Present (Full_View (Defining_Identifier (Decl))) and then Is_Unchecked_Union (Full_View (Defining_Identifier (Decl))) then Error_Msg_N ("completion of discriminated partial view " & "cannot be an Unchecked_Union", Full_View (Defining_Identifier (Decl))); end if; Next (Decl); end loop; end Inspect_Unchecked_Union_Completion; ----------------------------------------- -- Install_Parent_Private_Declarations -- ----------------------------------------- procedure Install_Parent_Private_Declarations (Inst_Id : Entity_Id) is Inst_Par : Entity_Id; Gen_Par : Entity_Id; Inst_Node : Node_Id; begin Inst_Par := Inst_Id; Gen_Par := Generic_Parent (Specification (Unit_Declaration_Node (Inst_Par))); while Present (Gen_Par) and then Is_Child_Unit (Gen_Par) loop Inst_Node := Get_Package_Instantiation_Node (Inst_Par); if Nkind_In (Inst_Node, N_Package_Instantiation, N_Formal_Package_Declaration) and then Nkind (Name (Inst_Node)) = N_Expanded_Name then Inst_Par := Entity (Prefix (Name (Inst_Node))); if Present (Renamed_Entity (Inst_Par)) then Inst_Par := Renamed_Entity (Inst_Par); end if; Gen_Par := Generic_Parent (Specification (Unit_Declaration_Node (Inst_Par))); -- Install the private declarations and private use clauses -- of a parent instance of the child instance, unless the -- parent instance private declarations have already been -- installed earlier in Analyze_Package_Specification, which -- happens when a generic child is instantiated, and the -- instance is a child of the parent instance. -- Installing the use clauses of the parent instance twice -- is both unnecessary and wrong, because it would cause the -- clauses to be chained to themselves in the use clauses -- list of the scope stack entry. That in turn would cause -- an endless loop from End_Use_Clauses upon scope exit. -- The parent is now fully visible. It may be a hidden open -- scope if we are currently compiling some child instance -- declared within it, but while the current instance is being -- compiled the parent is immediately visible. In particular -- its entities must remain visible if a stack save/restore -- takes place through a call to Rtsfind. if Present (Gen_Par) then if not In_Private_Part (Inst_Par) then Install_Private_Declarations (Inst_Par); Set_Use (Private_Declarations (Specification (Unit_Declaration_Node (Inst_Par)))); Set_Is_Hidden_Open_Scope (Inst_Par, False); end if; -- If we've reached the end of the generic instance parents, -- then finish off by looping through the nongeneric parents -- and installing their private declarations. else while Present (Inst_Par) and then Inst_Par /= Standard_Standard and then (not In_Open_Scopes (Inst_Par) or else not In_Private_Part (Inst_Par)) loop Install_Private_Declarations (Inst_Par); Set_Use (Private_Declarations (Specification (Unit_Declaration_Node (Inst_Par)))); Inst_Par := Scope (Inst_Par); end loop; exit; end if; else exit; end if; end loop; end Install_Parent_Private_Declarations; -- Start of processing for Analyze_Package_Specification begin if Present (Vis_Decls) then Analyze_Declarations (Vis_Decls); end if; -- Verify that incomplete types have received full declarations and -- also build invariant procedures for any types with invariants. E := First_Entity (Id); while Present (E) loop -- Check on incomplete types -- AI05-0213: A formal incomplete type has no completion if Ekind (E) = E_Incomplete_Type and then No (Full_View (E)) and then not Is_Generic_Type (E) then Error_Msg_N ("no declaration in visible part for incomplete}", E); end if; -- Build invariant procedures if Is_Type (E) and then Has_Invariants (E) then Build_Invariant_Procedure (E, N); end if; Next_Entity (E); end loop; if Is_Remote_Call_Interface (Id) and then Nkind (Parent (Parent (N))) = N_Compilation_Unit then Validate_RCI_Declarations (Id); end if; -- Save global references in the visible declarations, before installing -- private declarations of parent unit if there is one, because the -- privacy status of types defined in the parent will change. This is -- only relevant for generic child units, but is done in all cases for -- uniformity. if Ekind (Id) = E_Generic_Package and then Nkind (Orig_Decl) = N_Generic_Package_Declaration then declare Orig_Spec : constant Node_Id := Specification (Orig_Decl); Save_Priv : constant List_Id := Private_Declarations (Orig_Spec); begin Set_Private_Declarations (Orig_Spec, Empty_List); Save_Global_References (Orig_Decl); Set_Private_Declarations (Orig_Spec, Save_Priv); end; end if; -- If package is a public child unit, then make the private declarations -- of the parent visible. Public_Child := False; declare Par : Entity_Id; Pack_Decl : Node_Id; Par_Spec : Node_Id; begin Par := Id; Par_Spec := Parent_Spec (Parent (N)); -- If the package is formal package of an enclosing generic, it is -- transformed into a local generic declaration, and compiled to make -- its spec available. We need to retrieve the original generic to -- determine whether it is a child unit, and install its parents. if No (Par_Spec) and then Nkind (Original_Node (Parent (N))) = N_Formal_Package_Declaration then Par := Entity (Name (Original_Node (Parent (N)))); Par_Spec := Parent_Spec (Unit_Declaration_Node (Par)); end if; if Present (Par_Spec) then Generate_Parent_References; while Scope (Par) /= Standard_Standard and then Is_Public_Child (Id, Par) and then In_Open_Scopes (Par) loop Public_Child := True; Par := Scope (Par); Install_Private_Declarations (Par); Install_Private_With_Clauses (Par); Pack_Decl := Unit_Declaration_Node (Par); Set_Use (Private_Declarations (Specification (Pack_Decl))); end loop; end if; end; if Is_Compilation_Unit (Id) then Install_Private_With_Clauses (Id); else -- The current compilation unit may include private with_clauses, -- which are visible in the private part of the current nested -- package, and have to be installed now. This is not done for -- nested instantiations, where the private with_clauses of the -- enclosing unit have no effect once the instantiation info is -- established and we start analyzing the package declaration. declare Comp_Unit : constant Entity_Id := Cunit_Entity (Current_Sem_Unit); begin if Is_Package_Or_Generic_Package (Comp_Unit) and then not In_Private_Part (Comp_Unit) and then not In_Instance then Install_Private_With_Clauses (Comp_Unit); Private_With_Clauses_Installed := True; end if; end; end if; -- If this is a package associated with a generic instance or formal -- package, then the private declarations of each of the generic's -- parents must be installed at this point. if Is_Generic_Instance (Id) then Install_Parent_Private_Declarations (Id); end if; -- Analyze private part if present. The flag In_Private_Part is reset -- in End_Package_Scope. L := Last_Entity (Id); if Present (Priv_Decls) then Set_In_Private_Part (Id); -- Upon entering a public child's private part, it may be necessary -- to declare subprograms that were derived in the package's visible -- part but not yet made visible. if Public_Child then Declare_Inherited_Private_Subprograms (Id); end if; Analyze_Declarations (Priv_Decls); -- Check the private declarations for incomplete deferred constants Inspect_Deferred_Constant_Completion (Priv_Decls); -- The first private entity is the immediate follower of the last -- visible entity, if there was one. if Present (L) then Set_First_Private_Entity (Id, Next_Entity (L)); else Set_First_Private_Entity (Id, First_Entity (Id)); end if; -- There may be inherited private subprograms that need to be declared, -- even in the absence of an explicit private part. If there are any -- public declarations in the package and the package is a public child -- unit, then an implicit private part is assumed. elsif Present (L) and then Public_Child then Set_In_Private_Part (Id); Declare_Inherited_Private_Subprograms (Id); Set_First_Private_Entity (Id, Next_Entity (L)); end if; E := First_Entity (Id); while Present (E) loop -- Check rule of 3.6(11), which in general requires waiting till all -- full types have been seen. if Ekind (E) = E_Record_Type or else Ekind (E) = E_Array_Type then Check_Aliased_Component_Types (E); end if; -- Check preelaborable initialization for full type completing a -- private type for which pragma Preelaborable_Initialization given. if Is_Type (E) and then Must_Have_Preelab_Init (E) and then not Has_Preelaborable_Initialization (E) then Error_Msg_N ("full view of & does not have preelaborable initialization", E); end if; -- An invariant may appear on a full view of a type if Is_Type (E) and then Has_Private_Declaration (E) and then Nkind (Parent (E)) = N_Full_Type_Declaration and then Has_Aspects (Parent (E)) then Build_Invariant_Procedure (E, N); end if; Next_Entity (E); end loop; -- Ada 2005 (AI-216): The completion of an incomplete or private type -- declaration having a known_discriminant_part shall not be an -- Unchecked_Union type. if Present (Vis_Decls) then Inspect_Unchecked_Union_Completion (Vis_Decls); end if; if Present (Priv_Decls) then Inspect_Unchecked_Union_Completion (Priv_Decls); end if; if Ekind (Id) = E_Generic_Package and then Nkind (Orig_Decl) = N_Generic_Package_Declaration and then Present (Priv_Decls) then -- Save global references in private declarations, ignoring the -- visible declarations that were processed earlier. declare Orig_Spec : constant Node_Id := Specification (Orig_Decl); Save_Vis : constant List_Id := Visible_Declarations (Orig_Spec); Save_Form : constant List_Id := Generic_Formal_Declarations (Orig_Decl); begin Set_Visible_Declarations (Orig_Spec, Empty_List); Set_Generic_Formal_Declarations (Orig_Decl, Empty_List); Save_Global_References (Orig_Decl); Set_Generic_Formal_Declarations (Orig_Decl, Save_Form); Set_Visible_Declarations (Orig_Spec, Save_Vis); end; end if; Process_End_Label (N, 'e', Id); -- Remove private_with_clauses of enclosing compilation unit, if they -- were installed. if Private_With_Clauses_Installed then Remove_Private_With_Clauses (Cunit (Current_Sem_Unit)); end if; -- For the case of a library level package, we must go through all the -- entities clearing the indications that the value may be constant and -- not modified. Why? Because any client of this package may modify -- these values freely from anywhere. This also applies to any nested -- packages or generic packages. -- For now we unconditionally clear constants for packages that are -- instances of generic packages. The reason is that we do not have the -- body yet, and we otherwise think things are unreferenced when they -- are not. This should be fixed sometime (the effect is not terrible, -- we just lose some warnings, and also some cases of value propagation) -- ??? if Is_Library_Level_Entity (Id) or else Is_Generic_Instance (Id) then Clear_Constants (Id, First_Entity (Id)); Clear_Constants (Id, First_Private_Entity (Id)); end if; Check_One_Tagged_Type_Or_Extension_At_Most; end Analyze_Package_Specification; -------------------------------------- -- Analyze_Private_Type_Declaration -- -------------------------------------- procedure Analyze_Private_Type_Declaration (N : Node_Id) is PF : constant Boolean := Is_Pure (Enclosing_Lib_Unit_Entity); Id : constant Entity_Id := Defining_Identifier (N); begin Generate_Definition (Id); Set_Is_Pure (Id, PF); Init_Size_Align (Id); if not Is_Package_Or_Generic_Package (Current_Scope) or else In_Private_Part (Current_Scope) then Error_Msg_N ("invalid context for private declaration", N); end if; New_Private_Type (N, Id, N); Set_Depends_On_Private (Id); if Has_Aspects (N) then Analyze_Aspect_Specifications (N, Id); end if; end Analyze_Private_Type_Declaration; ---------------------------------- -- Check_Anonymous_Access_Types -- ---------------------------------- procedure Check_Anonymous_Access_Types (Spec_Id : Entity_Id; P_Body : Node_Id) is E : Entity_Id; IR : Node_Id; begin -- Itype references are only needed by gigi, to force elaboration of -- itypes. In the absence of code generation, they are not needed. if not Expander_Active then return; end if; E := First_Entity (Spec_Id); while Present (E) loop if Ekind (E) = E_Anonymous_Access_Type and then From_With_Type (E) then IR := Make_Itype_Reference (Sloc (P_Body)); Set_Itype (IR, E); if No (Declarations (P_Body)) then Set_Declarations (P_Body, New_List (IR)); else Prepend (IR, Declarations (P_Body)); end if; end if; Next_Entity (E); end loop; end Check_Anonymous_Access_Types; ------------------------------------------- -- Declare_Inherited_Private_Subprograms -- ------------------------------------------- procedure Declare_Inherited_Private_Subprograms (Id : Entity_Id) is function Is_Primitive_Of (T : Entity_Id; S : Entity_Id) return Boolean; -- Check whether an inherited subprogram S is an operation of an -- untagged derived type T. --------------------- -- Is_Primitive_Of -- --------------------- function Is_Primitive_Of (T : Entity_Id; S : Entity_Id) return Boolean is Formal : Entity_Id; begin -- If the full view is a scalar type, the type is the anonymous base -- type, but the operation mentions the first subtype, so check the -- signature against the base type. if Base_Type (Etype (S)) = Base_Type (T) then return True; else Formal := First_Formal (S); while Present (Formal) loop if Base_Type (Etype (Formal)) = Base_Type (T) then return True; end if; Next_Formal (Formal); end loop; return False; end if; end Is_Primitive_Of; -- Local variables E : Entity_Id; Op_List : Elist_Id; Op_Elmt : Elmt_Id; Op_Elmt_2 : Elmt_Id; Prim_Op : Entity_Id; New_Op : Entity_Id := Empty; Parent_Subp : Entity_Id; Tag : Entity_Id; -- Start of processing for Declare_Inherited_Private_Subprograms begin E := First_Entity (Id); while Present (E) loop -- If the entity is a nonprivate type extension whose parent type -- is declared in an open scope, then the type may have inherited -- operations that now need to be made visible. Ditto if the entity -- is a formal derived type in a child unit. if ((Is_Derived_Type (E) and then not Is_Private_Type (E)) or else (Nkind (Parent (E)) = N_Private_Extension_Declaration and then Is_Generic_Type (E))) and then In_Open_Scopes (Scope (Etype (E))) and then Is_Base_Type (E) then if Is_Tagged_Type (E) then Op_List := Primitive_Operations (E); New_Op := Empty; Tag := First_Tag_Component (E); Op_Elmt := First_Elmt (Op_List); while Present (Op_Elmt) loop Prim_Op := Node (Op_Elmt); -- Search primitives that are implicit operations with an -- internal name whose parent operation has a normal name. if Present (Alias (Prim_Op)) and then Find_Dispatching_Type (Alias (Prim_Op)) /= E and then not Comes_From_Source (Prim_Op) and then Is_Internal_Name (Chars (Prim_Op)) and then not Is_Internal_Name (Chars (Alias (Prim_Op))) then Parent_Subp := Alias (Prim_Op); -- Case 1: Check if the type has also an explicit -- overriding for this primitive. Op_Elmt_2 := Next_Elmt (Op_Elmt); while Present (Op_Elmt_2) loop -- Skip entities with attribute Interface_Alias since -- they are not overriding primitives (these entities -- link an interface primitive with their covering -- primitive) if Chars (Node (Op_Elmt_2)) = Chars (Parent_Subp) and then Type_Conformant (Prim_Op, Node (Op_Elmt_2)) and then No (Interface_Alias (Node (Op_Elmt_2))) then -- The private inherited operation has been -- overridden by an explicit subprogram: replace -- the former by the latter. New_Op := Node (Op_Elmt_2); Replace_Elmt (Op_Elmt, New_Op); Remove_Elmt (Op_List, Op_Elmt_2); Set_Overridden_Operation (New_Op, Parent_Subp); -- We don't need to inherit its dispatching slot. -- Set_All_DT_Position has previously ensured that -- the same slot was assigned to the two primitives if Present (Tag) and then Present (DTC_Entity (New_Op)) and then Present (DTC_Entity (Prim_Op)) then pragma Assert (DT_Position (New_Op) = DT_Position (Prim_Op)); null; end if; goto Next_Primitive; end if; Next_Elmt (Op_Elmt_2); end loop; -- Case 2: We have not found any explicit overriding and -- hence we need to declare the operation (i.e., make it -- visible). Derive_Subprogram (New_Op, Alias (Prim_Op), E, Etype (E)); -- Inherit the dispatching slot if E is already frozen if Is_Frozen (E) and then Present (DTC_Entity (Alias (Prim_Op))) then Set_DTC_Entity_Value (E, New_Op); Set_DT_Position (New_Op, DT_Position (Alias (Prim_Op))); end if; pragma Assert (Is_Dispatching_Operation (New_Op) and then Node (Last_Elmt (Op_List)) = New_Op); -- Substitute the new operation for the old one in the -- type's primitive operations list. Since the new -- operation was also just added to the end of list, -- the last element must be removed. -- (Question: is there a simpler way of declaring the -- operation, say by just replacing the name of the -- earlier operation, reentering it in the in the symbol -- table (how?), and marking it as private???) Replace_Elmt (Op_Elmt, New_Op); Remove_Last_Elmt (Op_List); end if; <<Next_Primitive>> Next_Elmt (Op_Elmt); end loop; -- Generate listing showing the contents of the dispatch table if Debug_Flag_ZZ then Write_DT (E); end if; else -- Non-tagged type, scan forward to locate inherited hidden -- operations. Prim_Op := Next_Entity (E); while Present (Prim_Op) loop if Is_Subprogram (Prim_Op) and then Present (Alias (Prim_Op)) and then not Comes_From_Source (Prim_Op) and then Is_Internal_Name (Chars (Prim_Op)) and then not Is_Internal_Name (Chars (Alias (Prim_Op))) and then Is_Primitive_Of (E, Prim_Op) then Derive_Subprogram (New_Op, Alias (Prim_Op), E, Etype (E)); end if; Next_Entity (Prim_Op); end loop; end if; end if; Next_Entity (E); end loop; end Declare_Inherited_Private_Subprograms; ----------------------- -- End_Package_Scope -- ----------------------- procedure End_Package_Scope (P : Entity_Id) is begin Uninstall_Declarations (P); Pop_Scope; end End_Package_Scope; --------------------------- -- Exchange_Declarations -- --------------------------- procedure Exchange_Declarations (Id : Entity_Id) is Full_Id : constant Entity_Id := Full_View (Id); H1 : constant Entity_Id := Homonym (Id); Next1 : constant Entity_Id := Next_Entity (Id); H2 : Entity_Id; Next2 : Entity_Id; begin -- If missing full declaration for type, nothing to exchange if No (Full_Id) then return; end if; -- Otherwise complete the exchange, and preserve semantic links Next2 := Next_Entity (Full_Id); H2 := Homonym (Full_Id); -- Reset full declaration pointer to reflect the switched entities and -- readjust the next entity chains. Exchange_Entities (Id, Full_Id); Set_Next_Entity (Id, Next1); Set_Homonym (Id, H1); Set_Full_View (Full_Id, Id); Set_Next_Entity (Full_Id, Next2); Set_Homonym (Full_Id, H2); end Exchange_Declarations; ---------------------------- -- Install_Package_Entity -- ---------------------------- procedure Install_Package_Entity (Id : Entity_Id) is begin if not Is_Internal (Id) then if Debug_Flag_E then Write_Str ("Install: "); Write_Name (Chars (Id)); Write_Eol; end if; if not Is_Child_Unit (Id) then Set_Is_Immediately_Visible (Id); end if; end if; end Install_Package_Entity; ---------------------------------- -- Install_Private_Declarations -- ---------------------------------- procedure Install_Private_Declarations (P : Entity_Id) is Id : Entity_Id; Priv_Elmt : Elmt_Id; Priv : Entity_Id; Full : Entity_Id; begin -- First exchange declarations for private types, so that the full -- declaration is visible. For each private type, we check its -- Private_Dependents list and also exchange any subtypes of or derived -- types from it. Finally, if this is a Taft amendment type, the -- incomplete declaration is irrelevant, and we want to link the -- eventual full declaration with the original private one so we also -- skip the exchange. Id := First_Entity (P); while Present (Id) and then Id /= First_Private_Entity (P) loop if Is_Private_Base_Type (Id) and then Comes_From_Source (Full_View (Id)) and then Present (Full_View (Id)) and then Scope (Full_View (Id)) = Scope (Id) and then Ekind (Full_View (Id)) /= E_Incomplete_Type then -- If there is a use-type clause on the private type, set the -- full view accordingly. Set_In_Use (Full_View (Id), In_Use (Id)); Full := Full_View (Id); if Is_Private_Base_Type (Full) and then Has_Private_Declaration (Full) and then Nkind (Parent (Full)) = N_Full_Type_Declaration and then In_Open_Scopes (Scope (Etype (Full))) and then In_Package_Body (Current_Scope) and then not Is_Private_Type (Etype (Full)) then -- This is the completion of a private type by a derivation -- from another private type which is not private anymore. This -- can only happen in a package nested within a child package, -- when the parent type is defined in the parent unit. At this -- point the current type is not private either, and we have to -- install the underlying full view, which is now visible. Save -- the current full view as well, so that all views can be -- restored on exit. It may seem that after compiling the child -- body there are not environments to restore, but the back-end -- expects those links to be valid, and freeze nodes depend on -- them. if No (Full_View (Full)) and then Present (Underlying_Full_View (Full)) then Set_Full_View (Id, Underlying_Full_View (Full)); Set_Underlying_Full_View (Id, Full); Set_Underlying_Full_View (Full, Empty); Set_Is_Frozen (Full_View (Id)); end if; end if; Priv_Elmt := First_Elmt (Private_Dependents (Id)); Exchange_Declarations (Id); Set_Is_Immediately_Visible (Id); while Present (Priv_Elmt) loop Priv := Node (Priv_Elmt); -- Before the exchange, verify that the presence of the -- Full_View field. It will be empty if the entity has already -- been installed due to a previous call. if Present (Full_View (Priv)) and then Is_Visible_Dependent (Priv) then -- For each subtype that is swapped, we also swap the -- reference to it in Private_Dependents, to allow access -- to it when we swap them out in End_Package_Scope. Replace_Elmt (Priv_Elmt, Full_View (Priv)); Exchange_Declarations (Priv); Set_Is_Immediately_Visible (Priv, In_Open_Scopes (Scope (Priv))); Set_Is_Potentially_Use_Visible (Priv, Is_Potentially_Use_Visible (Node (Priv_Elmt))); end if; Next_Elmt (Priv_Elmt); end loop; end if; Next_Entity (Id); end loop; -- Next make other declarations in the private part visible as well Id := First_Private_Entity (P); while Present (Id) loop Install_Package_Entity (Id); Set_Is_Hidden (Id, False); Next_Entity (Id); end loop; -- Indicate that the private part is currently visible, so it can be -- properly reset on exit. Set_In_Private_Part (P); end Install_Private_Declarations; ---------------------------------- -- Install_Visible_Declarations -- ---------------------------------- procedure Install_Visible_Declarations (P : Entity_Id) is Id : Entity_Id; Last_Entity : Entity_Id; begin pragma Assert (Is_Package_Or_Generic_Package (P) or else Is_Record_Type (P)); if Is_Package_Or_Generic_Package (P) then Last_Entity := First_Private_Entity (P); else Last_Entity := Empty; end if; Id := First_Entity (P); while Present (Id) and then Id /= Last_Entity loop Install_Package_Entity (Id); Next_Entity (Id); end loop; end Install_Visible_Declarations; -------------------------- -- Is_Private_Base_Type -- -------------------------- function Is_Private_Base_Type (E : Entity_Id) return Boolean is begin return Ekind (E) = E_Private_Type or else Ekind (E) = E_Limited_Private_Type or else Ekind (E) = E_Record_Type_With_Private; end Is_Private_Base_Type; -------------------------- -- Is_Visible_Dependent -- -------------------------- function Is_Visible_Dependent (Dep : Entity_Id) return Boolean is S : constant Entity_Id := Scope (Dep); begin -- Renamings created for actual types have the visibility of the actual if Ekind (S) = E_Package and then Is_Generic_Instance (S) and then (Is_Generic_Actual_Type (Dep) or else Is_Generic_Actual_Type (Full_View (Dep))) then return True; elsif not (Is_Derived_Type (Dep)) and then Is_Derived_Type (Full_View (Dep)) then -- When instantiating a package body, the scope stack is empty, so -- check instead whether the dependent type is defined in the same -- scope as the instance itself. return In_Open_Scopes (S) or else (Is_Generic_Instance (Current_Scope) and then Scope (Dep) = Scope (Current_Scope)); else return True; end if; end Is_Visible_Dependent; ---------------------------- -- May_Need_Implicit_Body -- ---------------------------- procedure May_Need_Implicit_Body (E : Entity_Id) is P : constant Node_Id := Unit_Declaration_Node (E); S : constant Node_Id := Parent (P); B : Node_Id; Decls : List_Id; begin if not Has_Completion (E) and then Nkind (P) = N_Package_Declaration and then (Present (Activation_Chain_Entity (P)) or else Has_RACW (E)) then B := Make_Package_Body (Sloc (E), Defining_Unit_Name => Make_Defining_Identifier (Sloc (E), Chars => Chars (E)), Declarations => New_List); if Nkind (S) = N_Package_Specification then if Present (Private_Declarations (S)) then Decls := Private_Declarations (S); else Decls := Visible_Declarations (S); end if; else Decls := Declarations (S); end if; Append (B, Decls); Analyze (B); end if; end May_Need_Implicit_Body; ---------------------- -- New_Private_Type -- ---------------------- procedure New_Private_Type (N : Node_Id; Id : Entity_Id; Def : Node_Id) is begin -- For other than Ada 2012, enter the name in the current scope if Ada_Version < Ada_2012 then Enter_Name (Id); -- Ada 2012 (AI05-0162): Enter the name in the current scope handling -- private type that completes an incomplete type. else declare Prev : Entity_Id; begin Prev := Find_Type_Name (N); pragma Assert (Prev = Id or else (Ekind (Prev) = E_Incomplete_Type and then Present (Full_View (Prev)) and then Full_View (Prev) = Id)); end; end if; if Limited_Present (Def) then Set_Ekind (Id, E_Limited_Private_Type); else Set_Ekind (Id, E_Private_Type); end if; Set_Etype (Id, Id); Set_Has_Delayed_Freeze (Id); Set_Is_First_Subtype (Id); Init_Size_Align (Id); Set_Is_Constrained (Id, No (Discriminant_Specifications (N)) and then not Unknown_Discriminants_Present (N)); -- Set tagged flag before processing discriminants, to catch illegal -- usage. Set_Is_Tagged_Type (Id, Tagged_Present (Def)); Set_Discriminant_Constraint (Id, No_Elist); Set_Stored_Constraint (Id, No_Elist); if Present (Discriminant_Specifications (N)) then Push_Scope (Id); Process_Discriminants (N); End_Scope; elsif Unknown_Discriminants_Present (N) then Set_Has_Unknown_Discriminants (Id); end if; Set_Private_Dependents (Id, New_Elmt_List); if Tagged_Present (Def) then Set_Ekind (Id, E_Record_Type_With_Private); Set_Direct_Primitive_Operations (Id, New_Elmt_List); Set_Is_Abstract_Type (Id, Abstract_Present (Def)); Set_Is_Limited_Record (Id, Limited_Present (Def)); Set_Has_Delayed_Freeze (Id, True); -- Create a class-wide type with the same attributes Make_Class_Wide_Type (Id); elsif Abstract_Present (Def) then Error_Msg_N ("only a tagged type can be abstract", N); end if; end New_Private_Type; ---------------------------- -- Uninstall_Declarations -- ---------------------------- procedure Uninstall_Declarations (P : Entity_Id) is Decl : constant Node_Id := Unit_Declaration_Node (P); Id : Entity_Id; Full : Entity_Id; Priv_Elmt : Elmt_Id; Priv_Sub : Entity_Id; procedure Preserve_Full_Attributes (Priv, Full : Entity_Id); -- Copy to the private declaration the attributes of the full view that -- need to be available for the partial view also. function Type_In_Use (T : Entity_Id) return Boolean; -- Check whether type or base type appear in an active use_type clause ------------------------------ -- Preserve_Full_Attributes -- ------------------------------ procedure Preserve_Full_Attributes (Priv, Full : Entity_Id) is Priv_Is_Base_Type : constant Boolean := Is_Base_Type (Priv); begin Set_Size_Info (Priv, (Full)); Set_RM_Size (Priv, RM_Size (Full)); Set_Size_Known_At_Compile_Time (Priv, Size_Known_At_Compile_Time (Full)); Set_Is_Volatile (Priv, Is_Volatile (Full)); Set_Treat_As_Volatile (Priv, Treat_As_Volatile (Full)); Set_Is_Ada_2005_Only (Priv, Is_Ada_2005_Only (Full)); Set_Is_Ada_2012_Only (Priv, Is_Ada_2012_Only (Full)); Set_Has_Pragma_Unmodified (Priv, Has_Pragma_Unmodified (Full)); Set_Has_Pragma_Unreferenced (Priv, Has_Pragma_Unreferenced (Full)); Set_Has_Pragma_Unreferenced_Objects (Priv, Has_Pragma_Unreferenced_Objects (Full)); if Is_Unchecked_Union (Full) then Set_Is_Unchecked_Union (Base_Type (Priv)); end if; -- Why is atomic not copied here ??? if Referenced (Full) then Set_Referenced (Priv); end if; if Priv_Is_Base_Type then Set_Is_Controlled (Priv, Is_Controlled (Base_Type (Full))); Set_Finalize_Storage_Only (Priv, Finalize_Storage_Only (Base_Type (Full))); Set_Has_Task (Priv, Has_Task (Base_Type (Full))); Set_Has_Controlled_Component (Priv, Has_Controlled_Component (Base_Type (Full))); end if; Set_Freeze_Node (Priv, Freeze_Node (Full)); if Is_Tagged_Type (Priv) and then Is_Tagged_Type (Full) and then not Error_Posted (Full) then if Is_Tagged_Type (Priv) then -- If the type is tagged, the tag itself must be available on -- the partial view, for expansion purposes. Set_First_Entity (Priv, First_Entity (Full)); -- If there are discriminants in the partial view, these remain -- visible. Otherwise only the tag itself is visible, and there -- are no nameable components in the partial view. if No (Last_Entity (Priv)) then Set_Last_Entity (Priv, First_Entity (Priv)); end if; end if; Set_Has_Discriminants (Priv, Has_Discriminants (Full)); if Has_Discriminants (Full) then Set_Discriminant_Constraint (Priv, Discriminant_Constraint (Full)); end if; end if; end Preserve_Full_Attributes; ----------------- -- Type_In_Use -- ----------------- function Type_In_Use (T : Entity_Id) return Boolean is begin return Scope (Base_Type (T)) = P and then (In_Use (T) or else In_Use (Base_Type (T))); end Type_In_Use; -- Start of processing for Uninstall_Declarations begin Id := First_Entity (P); while Present (Id) and then Id /= First_Private_Entity (P) loop if Debug_Flag_E then Write_Str ("unlinking visible entity "); Write_Int (Int (Id)); Write_Eol; end if; -- On exit from the package scope, we must preserve the visibility -- established by use clauses in the current scope. Two cases: -- a) If the entity is an operator, it may be a primitive operator of -- a type for which there is a visible use-type clause. -- b) for other entities, their use-visibility is determined by a -- visible use clause for the package itself. For a generic instance, -- the instantiation of the formals appears in the visible part, -- but the formals are private and remain so. if Ekind (Id) = E_Function and then Is_Operator_Symbol_Name (Chars (Id)) and then not Is_Hidden (Id) and then not Error_Posted (Id) then Set_Is_Potentially_Use_Visible (Id, In_Use (P) or else Type_In_Use (Etype (Id)) or else Type_In_Use (Etype (First_Formal (Id))) or else (Present (Next_Formal (First_Formal (Id))) and then Type_In_Use (Etype (Next_Formal (First_Formal (Id)))))); else if In_Use (P) and then not Is_Hidden (Id) then -- A child unit of a use-visible package remains use-visible -- only if it is itself a visible child unit. Otherwise it -- would remain visible in other contexts where P is use- -- visible, because once compiled it stays in the entity list -- of its parent unit. if Is_Child_Unit (Id) then Set_Is_Potentially_Use_Visible (Id, Is_Visible_Child_Unit (Id)); else Set_Is_Potentially_Use_Visible (Id); end if; else Set_Is_Potentially_Use_Visible (Id, False); end if; end if; -- Local entities are not immediately visible outside of the package Set_Is_Immediately_Visible (Id, False); -- If this is a private type with a full view (for example a local -- subtype of a private type declared elsewhere), ensure that the -- full view is also removed from visibility: it may be exposed when -- swapping views in an instantiation. if Is_Type (Id) and then Present (Full_View (Id)) then Set_Is_Immediately_Visible (Full_View (Id), False); end if; if Is_Tagged_Type (Id) and then Ekind (Id) = E_Record_Type then Check_Abstract_Overriding (Id); Check_Conventions (Id); end if; if (Ekind (Id) = E_Private_Type or else Ekind (Id) = E_Limited_Private_Type) and then No (Full_View (Id)) and then not Is_Generic_Type (Id) and then not Is_Derived_Type (Id) then Error_Msg_N ("missing full declaration for private type&", Id); elsif Ekind (Id) = E_Record_Type_With_Private and then not Is_Generic_Type (Id) and then No (Full_View (Id)) then if Nkind (Parent (Id)) = N_Private_Type_Declaration then Error_Msg_N ("missing full declaration for private type&", Id); else Error_Msg_N ("missing full declaration for private extension", Id); end if; -- Case of constant, check for deferred constant declaration with -- no full view. Likely just a matter of a missing expression, or -- accidental use of the keyword constant. elsif Ekind (Id) = E_Constant -- OK if constant value present and then No (Constant_Value (Id)) -- OK if full view present and then No (Full_View (Id)) -- OK if imported, since that provides the completion and then not Is_Imported (Id) -- OK if object declaration replaced by renaming declaration as -- a result of OK_To_Rename processing (e.g. for concatenation) and then Nkind (Parent (Id)) /= N_Object_Renaming_Declaration -- OK if object declaration with the No_Initialization flag set and then not (Nkind (Parent (Id)) = N_Object_Declaration and then No_Initialization (Parent (Id))) then -- If no private declaration is present, we assume the user did -- not intend a deferred constant declaration and the problem -- is simply that the initializing expression is missing. if not Has_Private_Declaration (Etype (Id)) then -- We assume that the user did not intend a deferred constant -- declaration, and the expression is just missing. Error_Msg_N ("constant declaration requires initialization expression", Parent (Id)); if Is_Limited_Type (Etype (Id)) then Error_Msg_N ("\if variable intended, remove CONSTANT from declaration", Parent (Id)); end if; -- Otherwise if a private declaration is present, then we are -- missing the full declaration for the deferred constant. else Error_Msg_N ("missing full declaration for deferred constant (RM 7.4)", Id); if Is_Limited_Type (Etype (Id)) then Error_Msg_N ("\if variable intended, remove CONSTANT from declaration", Parent (Id)); end if; end if; end if; Next_Entity (Id); end loop; -- If the specification was installed as the parent of a public child -- unit, the private declarations were not installed, and there is -- nothing to do. if not In_Private_Part (P) then return; else Set_In_Private_Part (P, False); end if; -- Make private entities invisible and exchange full and private -- declarations for private types. Id is now the first private entity -- in the package. while Present (Id) loop if Debug_Flag_E then Write_Str ("unlinking private entity "); Write_Int (Int (Id)); Write_Eol; end if; if Is_Tagged_Type (Id) and then Ekind (Id) = E_Record_Type then Check_Abstract_Overriding (Id); Check_Conventions (Id); end if; Set_Is_Immediately_Visible (Id, False); if Is_Private_Base_Type (Id) and then Present (Full_View (Id)) then Full := Full_View (Id); -- If the partial view is not declared in the visible part of the -- package (as is the case when it is a type derived from some -- other private type in the private part of the current package), -- no exchange takes place. if No (Parent (Id)) or else List_Containing (Parent (Id)) /= Visible_Declarations (Specification (Decl)) then goto Next_Id; end if; -- The entry in the private part points to the full declaration, -- which is currently visible. Exchange them so only the private -- type declaration remains accessible, and link private and full -- declaration in the opposite direction. Before the actual -- exchange, we copy back attributes of the full view that must -- be available to the partial view too. Preserve_Full_Attributes (Id, Full); Set_Is_Potentially_Use_Visible (Id, In_Use (P)); if Is_Indefinite_Subtype (Full) and then not Is_Indefinite_Subtype (Id) then Error_Msg_N ("full view of type must be definite subtype", Full); end if; Priv_Elmt := First_Elmt (Private_Dependents (Id)); -- Swap out the subtypes and derived types of Id that were -- compiled in this scope, or installed previously by -- Install_Private_Declarations. -- Before we do the swap, we verify the presence of the Full_View -- field which may be empty due to a swap by a previous call to -- End_Package_Scope (e.g. from the freezing mechanism). while Present (Priv_Elmt) loop Priv_Sub := Node (Priv_Elmt); if Present (Full_View (Priv_Sub)) then if Scope (Priv_Sub) = P or else not In_Open_Scopes (Scope (Priv_Sub)) then Set_Is_Immediately_Visible (Priv_Sub, False); end if; if Is_Visible_Dependent (Priv_Sub) then Preserve_Full_Attributes (Priv_Sub, Full_View (Priv_Sub)); Replace_Elmt (Priv_Elmt, Full_View (Priv_Sub)); Exchange_Declarations (Priv_Sub); end if; end if; Next_Elmt (Priv_Elmt); end loop; -- Now restore the type itself to its private view Exchange_Declarations (Id); -- If we have installed an underlying full view for a type derived -- from a private type in a child unit, restore the proper views -- of private and full view. See corresponding code in -- Install_Private_Declarations. -- After the exchange, Full denotes the private type in the -- visible part of the package. if Is_Private_Base_Type (Full) and then Present (Full_View (Full)) and then Present (Underlying_Full_View (Full)) and then In_Package_Body (Current_Scope) then Set_Full_View (Full, Underlying_Full_View (Full)); Set_Underlying_Full_View (Full, Empty); end if; elsif Ekind (Id) = E_Incomplete_Type and then Comes_From_Source (Id) and then No (Full_View (Id)) then -- Mark Taft amendment types. Verify that there are no primitive -- operations declared for the type (3.10.1(9)). Set_Has_Completion_In_Body (Id); declare Elmt : Elmt_Id; Subp : Entity_Id; begin Elmt := First_Elmt (Private_Dependents (Id)); while Present (Elmt) loop Subp := Node (Elmt); -- Is_Primitive is tested because there can be cases where -- nonprimitive subprograms (in nested packages) are added -- to the Private_Dependents list. if Is_Overloadable (Subp) and then Is_Primitive (Subp) then Error_Msg_NE ("type& must be completed in the private part", Parent (Subp), Id); -- The result type of an access-to-function type cannot be a -- Taft-amendment type, unless the version is Ada 2012 or -- later (see AI05-151). elsif Ada_Version < Ada_2012 and then Ekind (Subp) = E_Subprogram_Type then if Etype (Subp) = Id or else (Is_Class_Wide_Type (Etype (Subp)) and then Etype (Etype (Subp)) = Id) then Error_Msg_NE ("type& must be completed in the private part", Associated_Node_For_Itype (Subp), Id); end if; end if; Next_Elmt (Elmt); end loop; end; elsif not Is_Child_Unit (Id) and then (not Is_Private_Type (Id) or else No (Full_View (Id))) then Set_Is_Hidden (Id); Set_Is_Potentially_Use_Visible (Id, False); end if; <<Next_Id>> Next_Entity (Id); end loop; end Uninstall_Declarations; ------------------------ -- Unit_Requires_Body -- ------------------------ function Unit_Requires_Body (P : Entity_Id) return Boolean is E : Entity_Id; begin -- Imported entity never requires body. Right now, only subprograms can -- be imported, but perhaps in the future we will allow import of -- packages. if Is_Imported (P) then return False; -- Body required if library package with pragma Elaborate_Body elsif Has_Pragma_Elaborate_Body (P) then return True; -- Body required if subprogram elsif Is_Subprogram (P) or else Is_Generic_Subprogram (P) then return True; -- Treat a block as requiring a body elsif Ekind (P) = E_Block then return True; elsif Ekind (P) = E_Package and then Nkind (Parent (P)) = N_Package_Specification and then Present (Generic_Parent (Parent (P))) then declare G_P : constant Entity_Id := Generic_Parent (Parent (P)); begin if Has_Pragma_Elaborate_Body (G_P) then return True; end if; end; end if; -- Otherwise search entity chain for entity requiring completion E := First_Entity (P); while Present (E) loop -- Always ignore child units. Child units get added to the entity -- list of a parent unit, but are not original entities of the -- parent, and so do not affect whether the parent needs a body. if Is_Child_Unit (E) then null; -- Ignore formal packages and their renamings elsif Ekind (E) = E_Package and then Nkind (Original_Node (Unit_Declaration_Node (E))) = N_Formal_Package_Declaration then null; -- Otherwise test to see if entity requires a completion. -- Note that subprogram entities whose declaration does not come -- from source are ignored here on the basis that we assume the -- expander will provide an implicit completion at some point. elsif (Is_Overloadable (E) and then Ekind (E) /= E_Enumeration_Literal and then Ekind (E) /= E_Operator and then not Is_Abstract_Subprogram (E) and then not Has_Completion (E) and then Comes_From_Source (Parent (E))) or else (Ekind (E) = E_Package and then E /= P and then not Has_Completion (E) and then Unit_Requires_Body (E)) or else (Ekind (E) = E_Incomplete_Type and then No (Full_View (E)) and then not Is_Generic_Type (E)) or else ((Ekind (E) = E_Task_Type or else Ekind (E) = E_Protected_Type) and then not Has_Completion (E)) or else (Ekind (E) = E_Generic_Package and then E /= P and then not Has_Completion (E) and then Unit_Requires_Body (E)) or else (Is_Generic_Subprogram (E) and then not Has_Completion (E)) then return True; -- Entity that does not require completion else null; end if; Next_Entity (E); end loop; return False; end Unit_Requires_Body; end Sem_Ch7;
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