X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Fada%2Fexp_util.adb;h=93798b30eb23e24355674bfb7d8025d7eeb45eab;hb=afb9ca771908720c4a5d0a5600d29f51e9fa7805;hp=9d1c78bbe1ec3937540c8475444f170bb1bcc352;hpb=5c99c290e017aced8ef378745fd0070ec80894af;p=pf3gnuchains%2Fgcc-fork.git diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb index 9d1c78bbe1e..93798b30eb2 100644 --- a/gcc/ada/exp_util.adb +++ b/gcc/ada/exp_util.adb @@ -6,7 +6,7 @@ -- -- -- B o d y -- -- -- --- Copyright (C) 1992-2004, Free Software Foundation, Inc. -- +-- Copyright (C) 1992-2007, 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- -- @@ -16,8 +16,8 @@ -- 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. -- +-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- +-- Boston, MA 02110-1301, USA. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- @@ -26,17 +26,15 @@ with Atree; use Atree; with Checks; use Checks; +with Debug; use Debug; with Einfo; use Einfo; with Elists; use Elists; with Errout; use Errout; +with Exp_Aggr; use Exp_Aggr; with Exp_Ch7; use Exp_Ch7; -with Exp_Ch11; use Exp_Ch11; -with Exp_Tss; use Exp_Tss; -with Hostparm; use Hostparm; with Inline; use Inline; with Itypes; use Itypes; with Lib; use Lib; -with Namet; use Namet; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; @@ -46,8 +44,8 @@ with Sem; use Sem; with Sem_Ch8; use Sem_Ch8; with Sem_Eval; use Sem_Eval; with Sem_Res; use Sem_Res; +with Sem_Type; use Sem_Type; with Sem_Util; use Sem_Util; -with Sinfo; use Sinfo; with Snames; use Snames; with Stand; use Stand; with Stringt; use Stringt; @@ -68,8 +66,7 @@ package body Exp_Util is (Loc : Source_Ptr; Id_Ref : Node_Id; A_Type : Entity_Id; - Dyn : Boolean := False) - return Node_Id; + Dyn : Boolean := False) return Node_Id; -- Build function to generate the image string for a task that is an -- array component, concatenating the images of each index. To avoid -- storage leaks, the string is built with successive slice assignments. @@ -81,8 +78,7 @@ package body Exp_Util is (Loc : Source_Ptr; Decls : List_Id; Stats : List_Id; - Res : Entity_Id) - return Node_Id; + Res : Entity_Id) return Node_Id; -- Common processing for Task_Array_Image and Task_Record_Image. -- Build function body that computes image. @@ -101,8 +97,7 @@ package body Exp_Util is function Build_Task_Record_Image (Loc : Source_Ptr; Id_Ref : Node_Id; - Dyn : Boolean := False) - return Node_Id; + Dyn : Boolean := False) return Node_Id; -- Build function to generate the image string for a task that is a -- record component. Concatenate name of variable with that of selector. -- The flag Dyn indicates whether this is called for the initialization @@ -110,9 +105,8 @@ package body Exp_Util is -- created task that is assigned to a selected component. function Make_CW_Equivalent_Type - (T : Entity_Id; - E : Node_Id) - return Entity_Id; + (T : Entity_Id; + E : Node_Id) return Entity_Id; -- T is a class-wide type entity, E is the initial expression node that -- constrains T in case such as: " X: T := E" or "new T'(E)" -- This function returns the entity of the Equivalent type and inserts @@ -128,8 +122,7 @@ package body Exp_Util is function Make_Literal_Range (Loc : Source_Ptr; - Literal_Typ : Entity_Id) - return Node_Id; + Literal_Typ : Entity_Id) return Node_Id; -- Produce a Range node whose bounds are: -- Low_Bound (Literal_Type) .. -- Low_Bound (Literal_Type) + Length (Literal_Typ) - 1 @@ -137,9 +130,8 @@ package body Exp_Util is function New_Class_Wide_Subtype (CW_Typ : Entity_Id; - N : Node_Id) - return Entity_Id; - -- Create an implicit subtype of CW_Typ attached to node N. + N : Node_Id) return Entity_Id; + -- Create an implicit subtype of CW_Typ attached to node N ---------------------- -- Adjust_Condition -- @@ -274,13 +266,13 @@ package body Exp_Util is -------------------------- procedure Append_Freeze_Action (T : Entity_Id; N : Node_Id) is - Fnode : Node_Id := Freeze_Node (T); + Fnode : Node_Id; begin Ensure_Freeze_Node (T); Fnode := Freeze_Node (T); - if not Present (Actions (Fnode)) then + if No (Actions (Fnode)) then Set_Actions (Fnode, New_List); end if; @@ -376,14 +368,13 @@ package body Exp_Util is (Loc : Source_Ptr; Id_Ref : Node_Id; A_Type : Entity_Id; - Dyn : Boolean := False) - return Node_Id + Dyn : Boolean := False) return Node_Id is Dims : constant Nat := Number_Dimensions (A_Type); - -- Number of dimensions for array of tasks. + -- Number of dimensions for array of tasks Temps : array (1 .. Dims) of Entity_Id; - -- Array of temporaries to hold string for each index. + -- Array of temporaries to hold string for each index Indx : Node_Id; -- Index expression @@ -425,7 +416,8 @@ package body Exp_Util is Defining_Identifier => Pref, Object_Definition => New_Occurrence_Of (Standard_String, Loc), Expression => - Make_String_Literal (Loc, Strval => String_From_Name_Buffer))); + Make_String_Literal (Loc, + Strval => String_From_Name_Buffer))); else Append_To (Decls, @@ -495,7 +487,7 @@ package body Exp_Util is Make_Character_Literal (Loc, Chars => Name_Find, Char_Literal_Value => - Char_Code (Character'Pos ('('))))); + UI_From_Int (Character'Pos ('('))))); Append_To (Stats, Make_Assignment_Statement (Loc, @@ -554,7 +546,7 @@ package body Exp_Util is Make_Character_Literal (Loc, Chars => Name_Find, Char_Literal_Value => - Char_Code (Character'Pos (','))))); + UI_From_Int (Character'Pos (','))))); Append_To (Stats, Make_Assignment_Statement (Loc, @@ -577,7 +569,7 @@ package body Exp_Util is Make_Character_Literal (Loc, Chars => Name_Find, Char_Literal_Value => - Char_Code (Character'Pos (')'))))); + UI_From_Int (Character'Pos (')'))))); return Build_Task_Image_Function (Loc, Decls, Stats, Res); end Build_Task_Array_Image; @@ -586,10 +578,10 @@ package body Exp_Util is ---------------------------- function Build_Task_Image_Decls - (Loc : Source_Ptr; - Id_Ref : Node_Id; - A_Type : Entity_Id) - return List_Id + (Loc : Source_Ptr; + Id_Ref : Node_Id; + A_Type : Entity_Id; + In_Init_Proc : Boolean := False) return List_Id is Decls : constant List_Id := New_List; T_Id : Entity_Id := Empty; @@ -617,24 +609,27 @@ package body Exp_Util is Defining_Identifier => T_Id, Object_Definition => New_Occurrence_Of (Standard_String, Loc), Expression => - Make_String_Literal - (Loc, Strval => String_From_Name_Buffer))); + Make_String_Literal (Loc, + Strval => String_From_Name_Buffer))); else if Nkind (Id_Ref) = N_Identifier or else Nkind (Id_Ref) = N_Defining_Identifier then - -- For a simple variable, the image of the task is the name - -- of the variable. + -- For a simple variable, the image of the task is built from + -- the name of the variable. To avoid possible conflict with + -- the anonymous type created for a single protected object, + -- add a numeric suffix. T_Id := Make_Defining_Identifier (Loc, - New_External_Name (Chars (Id_Ref), 'T')); + New_External_Name (Chars (Id_Ref), 'T', 1)); Get_Name_String (Chars (Id_Ref)); - Expr := Make_String_Literal - (Loc, Strval => String_From_Name_Buffer); + Expr := + Make_String_Literal (Loc, + Strval => String_From_Name_Buffer); elsif Nkind (Id_Ref) = N_Selected_Component then T_Id := @@ -655,6 +650,10 @@ package body Exp_Util is Append (Fun, Decls); Expr := Make_Function_Call (Loc, Name => New_Occurrence_Of (Defining_Entity (Fun), Loc)); + + if not In_Init_Proc and then VM_Target = No_VM then + Set_Uses_Sec_Stack (Defining_Entity (Fun)); + end if; end if; Decl := Make_Object_Declaration (Loc, @@ -675,8 +674,7 @@ package body Exp_Util is (Loc : Source_Ptr; Decls : List_Id; Stats : List_Id; - Res : Entity_Id) - return Node_Id + Res : Entity_Id) return Node_Id is Spec : Node_Id; @@ -688,13 +686,11 @@ package body Exp_Util is Spec := Make_Function_Specification (Loc, Defining_Unit_Name => Make_Defining_Identifier (Loc, New_Internal_Name ('F')), - Subtype_Mark => New_Occurrence_Of (Standard_String, Loc)); + Result_Definition => New_Occurrence_Of (Standard_String, Loc)); -- Calls to 'Image use the secondary stack, which must be cleaned -- up after the task name is built. - Set_Uses_Sec_Stack (Defining_Unit_Name (Spec)); - return Make_Subprogram_Body (Loc, Specification => Spec, Declarations => Decls, @@ -789,8 +785,7 @@ package body Exp_Util is function Build_Task_Record_Image (Loc : Source_Ptr; Id_Ref : Node_Id; - Dyn : Boolean := False) - return Node_Id + Dyn : Boolean := False) return Node_Id is Len : Entity_Id; -- Total length of generated name @@ -805,7 +800,7 @@ package body Exp_Util is -- Name of enclosing variable, prefix of resulting name Sum : Node_Id; - -- Expression to compute total size of string. + -- Expression to compute total size of string Sel : Entity_Id; -- Entity for selector name @@ -826,7 +821,8 @@ package body Exp_Util is Defining_Identifier => Pref, Object_Definition => New_Occurrence_Of (Standard_String, Loc), Expression => - Make_String_Literal (Loc, Strval => String_From_Name_Buffer))); + Make_String_Literal (Loc, + Strval => String_From_Name_Buffer))); else Append_To (Decls, @@ -845,7 +841,8 @@ package body Exp_Util is Defining_Identifier => Sel, Object_Definition => New_Occurrence_Of (Standard_String, Loc), Expression => - Make_String_Literal (Loc, Strval => String_From_Name_Buffer))); + Make_String_Literal (Loc, + Strval => String_From_Name_Buffer))); Sum := Make_Integer_Literal (Loc, Nat (Name_Len + 1)); @@ -874,7 +871,7 @@ package body Exp_Util is Make_Character_Literal (Loc, Chars => Name_Find, Char_Literal_Value => - Char_Code (Character'Pos ('.'))))); + UI_From_Int (Character'Pos ('.'))))); Append_To (Stats, Make_Assignment_Statement (Loc, @@ -1008,8 +1005,7 @@ package body Exp_Util is function Duplicate_Subexpr (Exp : Node_Id; - Name_Req : Boolean := False) - return Node_Id + Name_Req : Boolean := False) return Node_Id is begin Remove_Side_Effects (Exp, Name_Req); @@ -1022,8 +1018,7 @@ package body Exp_Util is function Duplicate_Subexpr_No_Checks (Exp : Node_Id; - Name_Req : Boolean := False) - return Node_Id + Name_Req : Boolean := False) return Node_Id is New_Exp : Node_Id; @@ -1040,8 +1035,7 @@ package body Exp_Util is function Duplicate_Subexpr_Move_Checks (Exp : Node_Id; - Name_Req : Boolean := False) - return Node_Id + Name_Req : Boolean := False) return Node_Id is New_Exp : Node_Id; @@ -1073,7 +1067,6 @@ package body Exp_Util is -- in gigi. P := Parent (N); - while Present (P) and then Nkind (P) /= N_Subprogram_Body loop @@ -1132,8 +1125,8 @@ package body Exp_Util is -- objects which are constrained by an initial expression. Basically it -- transforms an unconstrained subtype indication into a constrained one. -- The expression may also be transformed in certain cases in order to - -- avoid multiple evaulation. In the static allocation case, the general - -- scheme is : + -- avoid multiple evaluation. In the static allocation case, the general + -- scheme is: -- Val : T := Expr; @@ -1226,9 +1219,32 @@ package body Exp_Util is then if Is_Itype (Exp_Typ) then - -- No need to generate a new one. + -- Within an initialization procedure, a selected component + -- denotes a component of the enclosing record, and it appears + -- as an actual in a call to its own initialization procedure. + -- If this component depends on the outer discriminant, we must + -- generate the proper actual subtype for it. + + if Nkind (Exp) = N_Selected_Component + and then Within_Init_Proc + then + declare + Decl : constant Node_Id := + Build_Actual_Subtype_Of_Component (Exp_Typ, Exp); + begin + if Present (Decl) then + Insert_Action (N, Decl); + T := Defining_Identifier (Decl); + else + T := Exp_Typ; + end if; + end; + + -- No need to generate a new one (new what???) - T := Exp_Typ; + else + T := Exp_Typ; + end if; else T := @@ -1261,6 +1277,47 @@ package body Exp_Util is then null; + -- Nothing to be done for derived types with unknown discriminants if + -- the parent type also has unknown discriminants. + + elsif Is_Record_Type (Unc_Type) + and then not Is_Class_Wide_Type (Unc_Type) + and then Has_Unknown_Discriminants (Unc_Type) + and then Has_Unknown_Discriminants (Underlying_Type (Unc_Type)) + then + null; + + -- In Ada95, Nothing to be done if the type of the expression is + -- limited, because in this case the expression cannot be copied, + -- and its use can only be by reference. + + -- In Ada2005, the context can be an object declaration whose expression + -- is a function that returns in place. If the nominal subtype has + -- unknown discriminants, the call still provides constraints on the + -- object, and we have to create an actual subtype from it. + + -- If the type is class-wide, the expression is dynamically tagged and + -- we do not create an actual subtype either. Ditto for an interface. + + elsif Is_Limited_Type (Exp_Typ) + and then + (Is_Class_Wide_Type (Exp_Typ) + or else Is_Interface (Exp_Typ) + or else not Has_Unknown_Discriminants (Exp_Typ) + or else not Is_Composite_Type (Unc_Type)) + then + null; + + -- For limited interfaces, nothing to be done + + -- This branch may be redundant once the limited interface issue is + -- sorted out??? + + elsif Is_Interface (Exp_Typ) + and then Is_Limited_Interface (Exp_Typ) + then + null; + else Remove_Side_Effects (Exp); Rewrite (Subtype_Indic, @@ -1268,6 +1325,391 @@ package body Exp_Util is end if; end Expand_Subtype_From_Expr; + ------------------------ + -- Find_Interface_ADT -- + ------------------------ + + function Find_Interface_ADT + (T : Entity_Id; + Iface : Entity_Id) return Entity_Id + is + ADT : Elmt_Id; + Found : Boolean := False; + Typ : Entity_Id := T; + + procedure Find_Secondary_Table (Typ : Entity_Id); + -- Internal subprogram used to recursively climb to the ancestors + + -------------------------- + -- Find_Secondary_Table -- + -------------------------- + + procedure Find_Secondary_Table (Typ : Entity_Id) is + AI_Elmt : Elmt_Id; + AI : Node_Id; + + begin + pragma Assert (Typ /= Iface); + + -- Climb to the ancestor (if any) handling synchronized interface + -- derivations and private types + + if Is_Concurrent_Record_Type (Typ) then + declare + Iface_List : constant List_Id := Abstract_Interface_List (Typ); + + begin + if Is_Non_Empty_List (Iface_List) then + Find_Secondary_Table (Etype (First (Iface_List))); + end if; + end; + + elsif Present (Full_View (Etype (Typ))) then + if Full_View (Etype (Typ)) /= Typ then + Find_Secondary_Table (Full_View (Etype (Typ))); + end if; + + elsif Etype (Typ) /= Typ then + Find_Secondary_Table (Etype (Typ)); + end if; + + -- Traverse the list of interfaces implemented by the type + + if not Found + and then Present (Abstract_Interfaces (Typ)) + and then not Is_Empty_Elmt_List (Abstract_Interfaces (Typ)) + then + AI_Elmt := First_Elmt (Abstract_Interfaces (Typ)); + while Present (AI_Elmt) loop + AI := Node (AI_Elmt); + + if AI = Iface or else Is_Ancestor (Iface, AI) then + Found := True; + return; + end if; + + Next_Elmt (ADT); + Next_Elmt (AI_Elmt); + end loop; + end if; + end Find_Secondary_Table; + + -- Start of processing for Find_Interface_ADT + + begin + pragma Assert (Is_Interface (Iface)); + + -- Handle private types + + if Has_Private_Declaration (Typ) + and then Present (Full_View (Typ)) + then + Typ := Full_View (Typ); + end if; + + -- Handle access types + + if Is_Access_Type (Typ) then + Typ := Directly_Designated_Type (Typ); + end if; + + -- Handle task and protected types implementing interfaces + + if Is_Concurrent_Type (Typ) then + Typ := Corresponding_Record_Type (Typ); + end if; + + pragma Assert + (not Is_Class_Wide_Type (Typ) + and then Ekind (Typ) /= E_Incomplete_Type); + + ADT := Next_Elmt (First_Elmt (Access_Disp_Table (Typ))); + pragma Assert (Present (Node (ADT))); + Find_Secondary_Table (Typ); + pragma Assert (Found); + return Node (ADT); + end Find_Interface_ADT; + + ------------------------ + -- Find_Interface_Tag -- + ------------------------ + + function Find_Interface_Tag + (T : Entity_Id; + Iface : Entity_Id) return Entity_Id + is + AI_Tag : Entity_Id; + Found : Boolean := False; + Typ : Entity_Id := T; + + Is_Primary_Tag : Boolean := False; + + Is_Sync_Typ : Boolean := False; + -- In case of non concurrent-record-types each parent-type has the + -- tags associated with the interface types that are not implemented + -- by the ancestors; concurrent-record-types have their whole list of + -- interface tags (and this case requires some special management). + + procedure Find_Tag (Typ : Entity_Id); + -- Internal subprogram used to recursively climb to the ancestors + + -------------- + -- Find_Tag -- + -------------- + + procedure Find_Tag (Typ : Entity_Id) is + AI_Elmt : Elmt_Id; + AI : Node_Id; + + begin + -- Check if the interface is an immediate ancestor of the type and + -- therefore shares the main tag. + + if Typ = Iface then + if Is_Sync_Typ then + Is_Primary_Tag := True; + else + pragma Assert + (Etype (First_Tag_Component (Typ)) = RTE (RE_Tag)); + AI_Tag := First_Tag_Component (Typ); + end if; + + Found := True; + return; + end if; + + -- Handle synchronized interface derivations + + if Is_Concurrent_Record_Type (Typ) then + declare + Iface_List : constant List_Id := Abstract_Interface_List (Typ); + begin + if Is_Non_Empty_List (Iface_List) then + Find_Tag (Etype (First (Iface_List))); + end if; + end; + + -- Climb to the root type handling private types + + elsif Present (Full_View (Etype (Typ))) then + if Full_View (Etype (Typ)) /= Typ then + Find_Tag (Full_View (Etype (Typ))); + end if; + + elsif Etype (Typ) /= Typ then + Find_Tag (Etype (Typ)); + end if; + + -- Traverse the list of interfaces implemented by the type + + if not Found + and then Present (Abstract_Interfaces (Typ)) + and then not (Is_Empty_Elmt_List (Abstract_Interfaces (Typ))) + then + -- Skip the tag associated with the primary table + + if not Is_Sync_Typ then + pragma Assert + (Etype (First_Tag_Component (Typ)) = RTE (RE_Tag)); + AI_Tag := Next_Tag_Component (First_Tag_Component (Typ)); + pragma Assert (Present (AI_Tag)); + end if; + + AI_Elmt := First_Elmt (Abstract_Interfaces (Typ)); + while Present (AI_Elmt) loop + AI := Node (AI_Elmt); + + if AI = Iface or else Is_Ancestor (Iface, AI) then + Found := True; + return; + end if; + + AI_Tag := Next_Tag_Component (AI_Tag); + Next_Elmt (AI_Elmt); + end loop; + end if; + end Find_Tag; + + -- Start of processing for Find_Interface_Tag + + begin + pragma Assert (Is_Interface (Iface)); + + -- Handle private types + + if Has_Private_Declaration (Typ) + and then Present (Full_View (Typ)) + then + Typ := Full_View (Typ); + end if; + + -- Handle access types + + if Is_Access_Type (Typ) then + Typ := Directly_Designated_Type (Typ); + end if; + + -- Handle task and protected types implementing interfaces + + if Is_Concurrent_Type (Typ) then + Typ := Corresponding_Record_Type (Typ); + end if; + + if Is_Class_Wide_Type (Typ) then + Typ := Etype (Typ); + end if; + + -- Handle entities from the limited view + + if Ekind (Typ) = E_Incomplete_Type then + pragma Assert (Present (Non_Limited_View (Typ))); + Typ := Non_Limited_View (Typ); + end if; + + if not Is_Concurrent_Record_Type (Typ) then + Find_Tag (Typ); + pragma Assert (Found); + return AI_Tag; + + -- Concurrent record types + + else + Is_Sync_Typ := True; + AI_Tag := Next_Tag_Component (First_Tag_Component (Typ)); + Find_Tag (Typ); + pragma Assert (Found); + + if Is_Primary_Tag then + return First_Tag_Component (Typ); + else + return AI_Tag; + end if; + end if; + end Find_Interface_Tag; + + -------------------- + -- Find_Interface -- + -------------------- + + function Find_Interface + (T : Entity_Id; + Comp : Entity_Id) return Entity_Id + is + AI_Tag : Entity_Id; + Found : Boolean := False; + Iface : Entity_Id; + Typ : Entity_Id := T; + + Is_Sync_Typ : Boolean := False; + -- In case of non concurrent-record-types each parent-type has the + -- tags associated with the interface types that are not implemented + -- by the ancestors; concurrent-record-types have their whole list of + -- interface tags (and this case requires some special management). + + procedure Find_Iface (Typ : Entity_Id); + -- Internal subprogram used to recursively climb to the ancestors + + ---------------- + -- Find_Iface -- + ---------------- + + procedure Find_Iface (Typ : Entity_Id) is + AI_Elmt : Elmt_Id; + + begin + -- Climb to the root type + + -- Handle sychronized interface derivations + + if Is_Concurrent_Record_Type (Typ) then + declare + Iface_List : constant List_Id := Abstract_Interface_List (Typ); + begin + if Is_Non_Empty_List (Iface_List) then + Find_Iface (Etype (First (Iface_List))); + end if; + end; + + -- Handle the common case + + elsif Etype (Typ) /= Typ then + pragma Assert (not Present (Full_View (Etype (Typ)))); + Find_Iface (Etype (Typ)); + end if; + + -- Traverse the list of interfaces implemented by the type + + if not Found + and then Present (Abstract_Interfaces (Typ)) + and then not (Is_Empty_Elmt_List (Abstract_Interfaces (Typ))) + then + -- Skip the tag associated with the primary table + + if not Is_Sync_Typ then + pragma Assert + (Etype (First_Tag_Component (Typ)) = RTE (RE_Tag)); + AI_Tag := Next_Tag_Component (First_Tag_Component (Typ)); + pragma Assert (Present (AI_Tag)); + end if; + + AI_Elmt := First_Elmt (Abstract_Interfaces (Typ)); + while Present (AI_Elmt) loop + if AI_Tag = Comp then + Iface := Node (AI_Elmt); + Found := True; + return; + end if; + + AI_Tag := Next_Tag_Component (AI_Tag); + Next_Elmt (AI_Elmt); + end loop; + end if; + end Find_Iface; + + -- Start of processing for Find_Interface + + begin + -- Handle private types + + if Has_Private_Declaration (Typ) + and then Present (Full_View (Typ)) + then + Typ := Full_View (Typ); + end if; + + -- Handle access types + + if Is_Access_Type (Typ) then + Typ := Directly_Designated_Type (Typ); + end if; + + -- Handle task and protected types implementing interfaces + + if Is_Concurrent_Type (Typ) then + Typ := Corresponding_Record_Type (Typ); + end if; + + if Is_Class_Wide_Type (Typ) then + Typ := Etype (Typ); + end if; + + -- Handle entities from the limited view + + if Ekind (Typ) = E_Incomplete_Type then + pragma Assert (Present (Non_Limited_View (Typ))); + Typ := Non_Limited_View (Typ); + end if; + + if Is_Concurrent_Record_Type (Typ) then + Is_Sync_Typ := True; + AI_Tag := Next_Tag_Component (First_Tag_Component (Typ)); + end if; + + Find_Iface (Typ); + pragma Assert (Found); + return Iface; + end Find_Interface; + ------------------ -- Find_Prim_Op -- ------------------ @@ -1275,6 +1717,7 @@ package body Exp_Util is function Find_Prim_Op (T : Entity_Id; Name : Name_Id) return Entity_Id is Prim : Elmt_Id; Typ : Entity_Id := T; + Op : Entity_Id; begin if Is_Class_Wide_Type (Typ) then @@ -1283,8 +1726,22 @@ package body Exp_Util is Typ := Underlying_Type (Typ); + -- Loop through primitive operations + Prim := First_Elmt (Primitive_Operations (Typ)); - while Chars (Node (Prim)) /= Name loop + while Present (Prim) loop + Op := Node (Prim); + + -- We can retrieve primitive operations by name if it is an internal + -- name. For equality we must check that both of its operands have + -- the same type, to avoid confusion with user-defined equalities + -- than may have a non-symmetric signature. + + exit when Chars (Op) = Name + and then + (Name /= Name_Op_Eq + or else Etype (First_Entity (Op)) = Etype (Last_Entity (Op))); + Next_Elmt (Prim); pragma Assert (Present (Prim)); end loop; @@ -1292,6 +1749,10 @@ package body Exp_Util is return Node (Prim); end Find_Prim_Op; + ------------------ + -- Find_Prim_Op -- + ------------------ + function Find_Prim_Op (T : Entity_Id; Name : TSS_Name_Type) return Entity_Id @@ -1320,41 +1781,8 @@ package body Exp_Util is ---------------------- procedure Force_Evaluation (Exp : Node_Id; Name_Req : Boolean := False) is - Component_In_Lhs : Boolean := False; - Par : Node_Id; - begin - -- Loop to determine whether there is a component reference in - -- the left hand side if this appears on the left side of an - -- assignment statement. Needed to determine if form of result - -- must be a variable. - - Par := Exp; - while Present (Par) - and then Nkind (Par) = N_Selected_Component - loop - if Nkind (Parent (Par)) = N_Assignment_Statement - and then Par = Name (Parent (Par)) - then - Component_In_Lhs := True; - exit; - else - Par := Parent (Par); - end if; - end loop; - - -- If the expression is a selected component, it is being evaluated - -- as part of a discriminant check. If it is part of a left-hand - -- side, this is the last use of its value and it is safe to create - -- a renaming for it, rather than a temporary. In addition, if it - -- is not an addressable field, creating a temporary may be a problem - -- for gigi, or might drop the value of the assignment. Therefore, - -- if the expression is on the lhs of an assignment, remove side - -- effects without requiring a temporary, and create a renaming. - -- (See remove_side_effects for details). - - Remove_Side_Effects - (Exp, Name_Req, Variable_Ref => not Component_In_Lhs); + Remove_Side_Effects (Exp, Name_Req, Variable_Ref => True); end Force_Evaluation; ------------------------ @@ -1381,175 +1809,363 @@ package body Exp_Util is -- Get_Current_Value_Condition -- --------------------------------- + -- Note: the implementation of this procedure is very closely tied to the + -- implementation of Set_Current_Value_Condition. In the Get procedure, we + -- interpret Current_Value fields set by the Set procedure, so the two + -- procedures need to be closely coordinated. + procedure Get_Current_Value_Condition (Var : Node_Id; Op : out Node_Kind; Val : out Node_Id) is - Loc : constant Source_Ptr := Sloc (Var); - CV : constant Node_Id := Current_Value (Entity (Var)); - Sens : Boolean; - Stm : Node_Id; - Cond : Node_Id; + Loc : constant Source_Ptr := Sloc (Var); + Ent : constant Entity_Id := Entity (Var); + + procedure Process_Current_Value_Condition + (N : Node_Id; + S : Boolean); + -- N is an expression which holds either True (S = True) or False (S = + -- False) in the condition. This procedure digs out the expression and + -- if it refers to Ent, sets Op and Val appropriately. + + ------------------------------------- + -- Process_Current_Value_Condition -- + ------------------------------------- + + procedure Process_Current_Value_Condition + (N : Node_Id; + S : Boolean) + is + Cond : Node_Id; + Sens : Boolean; - begin - Op := N_Empty; - Val := Empty; + begin + Cond := N; + Sens := S; - -- If statement. Condition is known true in THEN section, known False - -- in any ELSIF or ELSE part, and unknown outside the IF statement. + -- Deal with NOT operators, inverting sense - if Nkind (CV) = N_If_Statement then + while Nkind (Cond) = N_Op_Not loop + Cond := Right_Opnd (Cond); + Sens := not Sens; + end loop; - -- Before start of IF statement + -- Deal with AND THEN and AND cases - if Loc < Sloc (CV) then - return; + if Nkind (Cond) = N_And_Then + or else Nkind (Cond) = N_Op_And + then + -- Don't ever try to invert a condition that is of the form + -- of an AND or AND THEN (since we are not doing sufficiently + -- general processing to allow this). - -- After end of IF statement + if Sens = False then + Op := N_Empty; + Val := Empty; + return; + end if; - elsif Loc >= Sloc (CV) + Text_Ptr (UI_To_Int (End_Span (CV))) then - return; - end if; + -- Recursively process AND and AND THEN branches - -- At this stage we know that we are within the IF statement, but - -- unfortunately, the tree does not record the SLOC of the ELSE so - -- we cannot use a simple SLOC comparison to distinguish between - -- the then/else statements, so we have to climb the tree. + Process_Current_Value_Condition (Left_Opnd (Cond), True); - declare - N : Node_Id; + if Op /= N_Empty then + return; + end if; - begin - N := Parent (Var); - while Parent (N) /= CV loop - N := Parent (N); + Process_Current_Value_Condition (Right_Opnd (Cond), True); + return; - -- If we fall off the top of the tree, then that's odd, but - -- perhaps it could occur in some error situation, and the - -- safest response is simply to assume that the outcome of - -- the condition is unknown. No point in bombing during an - -- attempt to optimize things. + -- Case of relational operator - if No (N) then - return; - end if; - end loop; + elsif Nkind (Cond) in N_Op_Compare then + Op := Nkind (Cond); - -- Now we have N pointing to a node whose parent is the IF - -- statement in question, so now we can tell if we are within - -- the THEN statements. + -- Invert sense of test if inverted test - if Is_List_Member (N) - and then List_Containing (N) = Then_Statements (CV) - then - Sens := True; + if Sens = False then + case Op is + when N_Op_Eq => Op := N_Op_Ne; + when N_Op_Ne => Op := N_Op_Eq; + when N_Op_Lt => Op := N_Op_Ge; + when N_Op_Gt => Op := N_Op_Le; + when N_Op_Le => Op := N_Op_Gt; + when N_Op_Ge => Op := N_Op_Lt; + when others => raise Program_Error; + end case; + end if; - -- Otherwise we must be in ELSIF or ELSE part + -- Case of entity op value - else - Sens := False; - end if; - end; + if Is_Entity_Name (Left_Opnd (Cond)) + and then Ent = Entity (Left_Opnd (Cond)) + and then Compile_Time_Known_Value (Right_Opnd (Cond)) + then + Val := Right_Opnd (Cond); - -- ELSIF part. Condition is known true within the referenced - -- ELSIF, known False in any subsequent ELSIF or ELSE part, - -- and unknown before the ELSE part or after the IF statement. + -- Case of value op entity - elsif Nkind (CV) = N_Elsif_Part then - Stm := Parent (CV); + elsif Is_Entity_Name (Right_Opnd (Cond)) + and then Ent = Entity (Right_Opnd (Cond)) + and then Compile_Time_Known_Value (Left_Opnd (Cond)) + then + Val := Left_Opnd (Cond); - -- Before start of ELSIF part + -- We are effectively swapping operands - if Loc < Sloc (CV) then - return; + case Op is + when N_Op_Eq => null; + when N_Op_Ne => null; + when N_Op_Lt => Op := N_Op_Gt; + when N_Op_Gt => Op := N_Op_Lt; + when N_Op_Le => Op := N_Op_Ge; + when N_Op_Ge => Op := N_Op_Le; + when others => raise Program_Error; + end case; - -- After end of IF statement + else + Op := N_Empty; + end if; - elsif Loc >= Sloc (Stm) + - Text_Ptr (UI_To_Int (End_Span (Stm))) - then return; - end if; - -- Again we lack the SLOC of the ELSE, so we need to climb the - -- tree to see if we are within the ELSIF part in question. + -- Case of Boolean variable reference, return as though the + -- reference had said var = True. - declare - N : Node_Id; + else + if Is_Entity_Name (Cond) + and then Ent = Entity (Cond) + then + Val := New_Occurrence_Of (Standard_True, Sloc (Cond)); - begin - N := Parent (Var); - while Parent (N) /= Stm loop - N := Parent (N); + if Sens = False then + Op := N_Op_Ne; + else + Op := N_Op_Eq; + end if; + end if; + end if; + end Process_Current_Value_Condition; - -- If we fall off the top of the tree, then that's odd, but - -- perhaps it could occur in some error situation, and the - -- safest response is simply to assume that the outcome of - -- the condition is unknown. No point in bombing during an - -- attempt to optimize things. + -- Start of processing for Get_Current_Value_Condition - if No (N) then + begin + Op := N_Empty; + Val := Empty; + + -- Immediate return, nothing doing, if this is not an object + + if Ekind (Ent) not in Object_Kind then + return; + end if; + + -- Otherwise examine current value + + declare + CV : constant Node_Id := Current_Value (Ent); + Sens : Boolean; + Stm : Node_Id; + + begin + -- If statement. Condition is known true in THEN section, known False + -- in any ELSIF or ELSE part, and unknown outside the IF statement. + + if Nkind (CV) = N_If_Statement then + + -- Before start of IF statement + + if Loc < Sloc (CV) then + return; + + -- After end of IF statement + + elsif Loc >= Sloc (CV) + Text_Ptr (UI_To_Int (End_Span (CV))) then + return; + end if; + + -- At this stage we know that we are within the IF statement, but + -- unfortunately, the tree does not record the SLOC of the ELSE so + -- we cannot use a simple SLOC comparison to distinguish between + -- the then/else statements, so we have to climb the tree. + + declare + N : Node_Id; + + begin + N := Parent (Var); + while Parent (N) /= CV loop + N := Parent (N); + + -- If we fall off the top of the tree, then that's odd, but + -- perhaps it could occur in some error situation, and the + -- safest response is simply to assume that the outcome of + -- the condition is unknown. No point in bombing during an + -- attempt to optimize things. + + if No (N) then + return; + end if; + end loop; + + -- Now we have N pointing to a node whose parent is the IF + -- statement in question, so now we can tell if we are within + -- the THEN statements. + + if Is_List_Member (N) + and then List_Containing (N) = Then_Statements (CV) + then + Sens := True; + + -- If the variable reference does not come from source, we + -- cannot reliably tell whether it appears in the else part. + -- In particular, if if appears in generated code for a node + -- that requires finalization, it may be attached to a list + -- that has not been yet inserted into the code. For now, + -- treat it as unknown. + + elsif not Comes_From_Source (N) then return; + + -- Otherwise we must be in ELSIF or ELSE part + + else + Sens := False; end if; - end loop; + end; - -- Now we have N pointing to a node whose parent is the IF - -- statement in question, so see if is the ELSIF part we want. - -- the THEN statements. + -- ELSIF part. Condition is known true within the referenced + -- ELSIF, known False in any subsequent ELSIF or ELSE part, and + -- unknown before the ELSE part or after the IF statement. - if N = CV then - Sens := True; + elsif Nkind (CV) = N_Elsif_Part then + Stm := Parent (CV); - -- Otherwise we must be in susbequent ELSIF or ELSE part + -- Before start of ELSIF part - else - Sens := False; + if Loc < Sloc (CV) then + return; + + -- After end of IF statement + + elsif Loc >= Sloc (Stm) + + Text_Ptr (UI_To_Int (End_Span (Stm))) + then + return; end if; - end; - -- All other cases of Current_Value settings + -- Again we lack the SLOC of the ELSE, so we need to climb the + -- tree to see if we are within the ELSIF part in question. - else - return; - end if; + declare + N : Node_Id; - -- If we fall through here, then we have a reportable - -- condition, Sens is True if the condition is true and - -- False if it needs inverting. + begin + N := Parent (Var); + while Parent (N) /= Stm loop + N := Parent (N); - Cond := Condition (CV); + -- If we fall off the top of the tree, then that's odd, but + -- perhaps it could occur in some error situation, and the + -- safest response is simply to assume that the outcome of + -- the condition is unknown. No point in bombing during an + -- attempt to optimize things. - -- Deal with NOT operators, inverting sense + if No (N) then + return; + end if; + end loop; - while Nkind (Cond) = N_Op_Not loop - Cond := Right_Opnd (Cond); - Sens := not Sens; - end loop; + -- Now we have N pointing to a node whose parent is the IF + -- statement in question, so see if is the ELSIF part we want. + -- the THEN statements. - -- Now we must have a relational operator + if N = CV then + Sens := True; - pragma Assert (Entity (Var) = Entity (Left_Opnd (Cond))); - Val := Right_Opnd (Cond); - Op := Nkind (Cond); + -- Otherwise we must be in susbequent ELSIF or ELSE part - if Sens = False then - case Op is - when N_Op_Eq => Op := N_Op_Ne; - when N_Op_Ne => Op := N_Op_Eq; - when N_Op_Lt => Op := N_Op_Ge; - when N_Op_Gt => Op := N_Op_Le; - when N_Op_Le => Op := N_Op_Gt; - when N_Op_Ge => Op := N_Op_Lt; + else + Sens := False; + end if; + end; - -- No other entry should be possible + -- Iteration scheme of while loop. The condition is known to be + -- true within the body of the loop. - when others => - raise Program_Error; - end case; - end if; + elsif Nkind (CV) = N_Iteration_Scheme then + declare + Loop_Stmt : constant Node_Id := Parent (CV); + + begin + -- Before start of body of loop + + if Loc < Sloc (Loop_Stmt) then + return; + + -- After end of LOOP statement + + elsif Loc >= Sloc (End_Label (Loop_Stmt)) then + return; + + -- We are within the body of the loop + + else + Sens := True; + end if; + end; + + -- All other cases of Current_Value settings + + else + return; + end if; + + -- If we fall through here, then we have a reportable condition, Sens + -- is True if the condition is true and False if it needs inverting. + + Process_Current_Value_Condition (Condition (CV), Sens); + end; end Get_Current_Value_Condition; + --------------------------------- + -- Has_Controlled_Coextensions -- + --------------------------------- + + function Has_Controlled_Coextensions (Typ : Entity_Id) return Boolean is + D_Typ : Entity_Id; + Discr : Entity_Id; + + begin + -- Only consider record types + + if Ekind (Typ) /= E_Record_Type + and then Ekind (Typ) /= E_Record_Subtype + then + return False; + end if; + + if Has_Discriminants (Typ) then + Discr := First_Discriminant (Typ); + while Present (Discr) loop + D_Typ := Etype (Discr); + + if Ekind (D_Typ) = E_Anonymous_Access_Type + and then + (Is_Controlled (Directly_Designated_Type (D_Typ)) + or else + Is_Concurrent_Type (Directly_Designated_Type (D_Typ))) + then + return True; + end if; + + Next_Discriminant (Discr); + end loop; + end if; + + return False; + end Has_Controlled_Coextensions; + -------------------- -- Homonym_Number -- -------------------- @@ -1708,7 +2324,7 @@ package body Exp_Util is -- Capture root of the transient scope if Scope_Is_Transient then - Wrapped_Node := Node_To_Be_Wrapped; + Wrapped_Node := Node_To_Be_Wrapped; end if; loop @@ -1814,7 +2430,7 @@ package body Exp_Util is return; end if; - -- Statements, declarations, pragmas, representation clauses. + -- Statements, declarations, pragmas, representation clauses when -- Statements @@ -1839,8 +2455,9 @@ package body Exp_Util is N_Entry_Body | N_Exception_Declaration | N_Exception_Renaming_Declaration | + N_Formal_Abstract_Subprogram_Declaration | + N_Formal_Concrete_Subprogram_Declaration | N_Formal_Object_Declaration | - N_Formal_Subprogram_Declaration | N_Formal_Type_Declaration | N_Full_Type_Declaration | N_Function_Instantiation | @@ -1886,8 +2503,9 @@ package body Exp_Util is null; -- Do not insert if parent of P is an N_Component_Association - -- node (i.e. we are in the context of an N_Aggregate node. - -- In this case we want to insert before the entire aggregate. + -- node (i.e. we are in the context of an N_Aggregate or + -- N_Extension_Aggregate node. In this case we want to insert + -- before the entire aggregate. elsif Nkind (Parent (P)) = N_Component_Association then null; @@ -1921,7 +2539,7 @@ package body Exp_Util is -- Otherwise we can go ahead and do the insertion - elsif P = Wrapped_Node then + elsif P = Wrapped_Node then Store_Before_Actions_In_Scope (Ins_Actions); return; @@ -1976,13 +2594,14 @@ package body Exp_Util is else declare - Decl : Node_Id := Assoc_Node; + Decl : Node_Id; begin -- Check whether these actions were generated -- by a declaration that is part of the loop_ -- actions for the component_association. + Decl := Assoc_Node; while Present (Decl) loop exit when Parent (Decl) = P and then Is_List_Member (Decl) @@ -2127,10 +2746,16 @@ package body Exp_Util is N_Package_Specification | N_Parameter_Association | N_Parameter_Specification | + N_Pop_Constraint_Error_Label | + N_Pop_Program_Error_Label | + N_Pop_Storage_Error_Label | N_Pragma_Argument_Association | N_Procedure_Specification | N_Protected_Body | N_Protected_Definition | + N_Push_Constraint_Error_Label | + N_Push_Program_Error_Label | + N_Push_Storage_Error_Label | N_Qualified_Expression | N_Range | N_Range_Constraint | @@ -2160,8 +2785,7 @@ package body Exp_Util is N_Variant | N_Variant_Part | N_Validate_Unchecked_Conversion | - N_With_Clause | - N_With_Type_Clause + N_With_Clause => null; @@ -2190,19 +2814,19 @@ package body Exp_Util is P := Parent (N); end if; end loop; - end Insert_Actions; -- Version with check(s) suppressed procedure Insert_Actions - (Assoc_Node : Node_Id; Ins_Actions : List_Id; Suppress : Check_Id) + (Assoc_Node : Node_Id; + Ins_Actions : List_Id; + Suppress : Check_Id) is begin if Suppress = All_Checks then declare Svg : constant Suppress_Array := Scope_Suppress; - begin Scope_Suppress := (others => True); Insert_Actions (Assoc_Node, Ins_Actions); @@ -2212,7 +2836,6 @@ package body Exp_Util is else declare Svg : constant Boolean := Scope_Suppress (Suppress); - begin Scope_Suppress (Suppress) := True; Insert_Actions (Assoc_Node, Ins_Actions); @@ -2247,7 +2870,8 @@ package body Exp_Util is Aux : constant Node_Id := Aux_Decls_Node (Cunit (Main_Unit)); begin - New_Scope (Cunit_Entity (Main_Unit)); + Push_Scope (Cunit_Entity (Main_Unit)); + -- ??? should this be Current_Sem_Unit instead of Main_Unit? if No (Actions (Aux)) then Set_Actions (Aux, New_List (N)); @@ -2268,7 +2892,8 @@ package body Exp_Util is begin if Is_Non_Empty_List (L) then - New_Scope (Cunit_Entity (Main_Unit)); + Push_Scope (Cunit_Entity (Main_Unit)); + -- ??? should this be Current_Sem_Unit instead of Main_Unit? if No (Actions (Aux)) then Set_Actions (Aux, L); @@ -2323,54 +2948,184 @@ package body Exp_Util is return True; end Is_All_Null_Statements; + ----------------------------------------- + -- Is_Predefined_Dispatching_Operation -- + ----------------------------------------- + + function Is_Predefined_Dispatching_Operation (E : Entity_Id) return Boolean + is + TSS_Name : TSS_Name_Type; + + begin + if not Is_Dispatching_Operation (E) then + return False; + end if; + + Get_Name_String (Chars (E)); + + if Name_Len > TSS_Name_Type'Last then + TSS_Name := TSS_Name_Type (Name_Buffer (Name_Len - TSS_Name'Length + 1 + .. Name_Len)); + if Chars (E) = Name_uSize + or else Chars (E) = Name_uAlignment + or else TSS_Name = TSS_Stream_Read + or else TSS_Name = TSS_Stream_Write + or else TSS_Name = TSS_Stream_Input + or else TSS_Name = TSS_Stream_Output + or else + (Chars (E) = Name_Op_Eq + and then Etype (First_Entity (E)) = Etype (Last_Entity (E))) + or else Chars (E) = Name_uAssign + or else TSS_Name = TSS_Deep_Adjust + or else TSS_Name = TSS_Deep_Finalize + or else (Ada_Version >= Ada_05 + and then (Chars (E) = Name_uDisp_Asynchronous_Select + or else Chars (E) = Name_uDisp_Conditional_Select + or else Chars (E) = Name_uDisp_Get_Prim_Op_Kind + or else Chars (E) = Name_uDisp_Get_Task_Id + or else Chars (E) = Name_uDisp_Timed_Select)) + then + return True; + end if; + end if; + + return False; + end Is_Predefined_Dispatching_Operation; + ---------------------------------- -- Is_Possibly_Unaligned_Object -- ---------------------------------- - function Is_Possibly_Unaligned_Object (P : Node_Id) return Boolean is + function Is_Possibly_Unaligned_Object (N : Node_Id) return Boolean is + T : constant Entity_Id := Etype (N); + begin - -- If target does not have strict alignment, result is always - -- False, since correctness of code does no depend on alignment. + -- If renamed object, apply test to underlying object - if not Target_Strict_Alignment then - return False; + if Is_Entity_Name (N) + and then Is_Object (Entity (N)) + and then Present (Renamed_Object (Entity (N))) + then + return Is_Possibly_Unaligned_Object (Renamed_Object (Entity (N))); end if; - -- If renamed object, apply test to underlying object + -- Tagged and controlled types and aliased types are always aligned, + -- as are concurrent types. - if Is_Entity_Name (P) - and then Is_Object (Entity (P)) - and then Present (Renamed_Object (Entity (P))) + if Is_Aliased (T) + or else Has_Controlled_Component (T) + or else Is_Concurrent_Type (T) + or else Is_Tagged_Type (T) + or else Is_Controlled (T) then - return Is_Possibly_Unaligned_Object (Renamed_Object (Entity (P))); + return False; end if; -- If this is an element of a packed array, may be unaligned - if Is_Ref_To_Bit_Packed_Array (P) then + if Is_Ref_To_Bit_Packed_Array (N) then return True; end if; -- Case of component reference - if Nkind (P) = N_Selected_Component then + if Nkind (N) = N_Selected_Component then + declare + P : constant Node_Id := Prefix (N); + C : constant Entity_Id := Entity (Selector_Name (N)); + M : Nat; + S : Nat; - -- If component reference is for a record that is bit packed - -- or has a specified alignment (that might be too small) or - -- the component reference has a component clause, then the - -- object may be unaligned. + begin + -- If component reference is for an array with non-static bounds, + -- then it is always aligned: we can only process unaligned + -- arrays with static bounds (more accurately bounds known at + -- compile time). - if Is_Packed (Etype (Prefix (P))) - or else Known_Alignment (Etype (Prefix (P))) - or else Present (Component_Clause (Entity (Selector_Name (P)))) - then - return True; + if Is_Array_Type (T) + and then not Compile_Time_Known_Bounds (T) + then + return False; + end if; - -- Otherwise, for a component reference, test prefix + -- If component is aliased, it is definitely properly aligned - else - return Is_Possibly_Unaligned_Object (Prefix (P)); - end if; + if Is_Aliased (C) then + return False; + end if; + + -- If component is for a type implemented as a scalar, and the + -- record is packed, and the component is other than the first + -- component of the record, then the component may be unaligned. + + if Is_Packed (Etype (P)) + and then Represented_As_Scalar (Etype (C)) + and then First_Entity (Scope (C)) /= C + then + return True; + end if; + + -- Compute maximum possible alignment for T + + -- If alignment is known, then that settles things + + if Known_Alignment (T) then + M := UI_To_Int (Alignment (T)); + + -- If alignment is not known, tentatively set max alignment + + else + M := Ttypes.Maximum_Alignment; + + -- We can reduce this if the Esize is known since the default + -- alignment will never be more than the smallest power of 2 + -- that does not exceed this Esize value. + + if Known_Esize (T) then + S := UI_To_Int (Esize (T)); + + while (M / 2) >= S loop + M := M / 2; + end loop; + end if; + end if; + + -- If the component reference is for a record that has a specified + -- alignment, and we either know it is too small, or cannot tell, + -- then the component may be unaligned + + if Known_Alignment (Etype (P)) + and then Alignment (Etype (P)) < Ttypes.Maximum_Alignment + and then M > Alignment (Etype (P)) + then + return True; + end if; + + -- Case of component clause present which may specify an + -- unaligned position. + + if Present (Component_Clause (C)) then + + -- Otherwise we can do a test to make sure that the actual + -- start position in the record, and the length, are both + -- consistent with the required alignment. If not, we know + -- that we are unaligned. + + declare + Align_In_Bits : constant Nat := M * System_Storage_Unit; + begin + if Component_Bit_Offset (C) mod Align_In_Bits /= 0 + or else Esize (C) mod Align_In_Bits /= 0 + then + return True; + end if; + end; + end if; + + -- Otherwise, for a component reference, test prefix + + return Is_Possibly_Unaligned_Object (P); + end; -- If not a component reference, must be aligned @@ -2383,27 +3138,20 @@ package body Exp_Util is -- Is_Possibly_Unaligned_Slice -- --------------------------------- - function Is_Possibly_Unaligned_Slice (P : Node_Id) return Boolean is + function Is_Possibly_Unaligned_Slice (N : Node_Id) return Boolean is begin - -- ??? GCC3 will eventually handle strings with arbitrary alignments, - -- but for now the following check must be disabled. + -- Go to renamed object - -- if get_gcc_version >= 3 then - -- return False; - -- end if; - - -- For renaming case, go to renamed object - - if Is_Entity_Name (P) - and then Is_Object (Entity (P)) - and then Present (Renamed_Object (Entity (P))) + if Is_Entity_Name (N) + and then Is_Object (Entity (N)) + and then Present (Renamed_Object (Entity (N))) then - return Is_Possibly_Unaligned_Slice (Renamed_Object (Entity (P))); + return Is_Possibly_Unaligned_Slice (Renamed_Object (Entity (N))); end if; -- The reference must be a slice - if Nkind (P) /= N_Slice then + if Nkind (N) /= N_Slice then return False; end if; @@ -2411,10 +3159,10 @@ package body Exp_Util is -- component clause, which gigi/gcc does not appear to handle well. -- It is not clear why this special test is needed at all ??? - if Nkind (Prefix (P)) = N_Selected_Component - and then Nkind (Prefix (Prefix (P))) = N_Selected_Component + if Nkind (Prefix (N)) = N_Selected_Component + and then Nkind (Prefix (Prefix (N))) = N_Selected_Component and then - Present (Component_Clause (Entity (Selector_Name (Prefix (P))))) + Present (Component_Clause (Entity (Selector_Name (Prefix (N))))) then return True; end if; @@ -2428,10 +3176,10 @@ package body Exp_Util is -- If it is a slice, then look at the array type being sliced declare - Sarr : constant Node_Id := Prefix (P); + Sarr : constant Node_Id := Prefix (N); -- Prefix of the slice, i.e. the array being sliced - Styp : constant Entity_Id := Etype (Prefix (P)); + Styp : constant Entity_Id := Etype (Prefix (N)); -- Type of the array being sliced Pref : Node_Id; @@ -2523,31 +3271,30 @@ package body Exp_Util is -- Is_Ref_To_Bit_Packed_Array -- -------------------------------- - function Is_Ref_To_Bit_Packed_Array (P : Node_Id) return Boolean is + function Is_Ref_To_Bit_Packed_Array (N : Node_Id) return Boolean is Result : Boolean; Expr : Node_Id; begin - if Is_Entity_Name (P) - and then Is_Object (Entity (P)) - and then Present (Renamed_Object (Entity (P))) + if Is_Entity_Name (N) + and then Is_Object (Entity (N)) + and then Present (Renamed_Object (Entity (N))) then - return Is_Ref_To_Bit_Packed_Array (Renamed_Object (Entity (P))); + return Is_Ref_To_Bit_Packed_Array (Renamed_Object (Entity (N))); end if; - if Nkind (P) = N_Indexed_Component + if Nkind (N) = N_Indexed_Component or else - Nkind (P) = N_Selected_Component + Nkind (N) = N_Selected_Component then - if Is_Bit_Packed_Array (Etype (Prefix (P))) then + if Is_Bit_Packed_Array (Etype (Prefix (N))) then Result := True; else - Result := Is_Ref_To_Bit_Packed_Array (Prefix (P)); + Result := Is_Ref_To_Bit_Packed_Array (Prefix (N)); end if; - if Result and then Nkind (P) = N_Indexed_Component then - Expr := First (Expressions (P)); - + if Result and then Nkind (N) = N_Indexed_Component then + Expr := First (Expressions (N)); while Present (Expr) loop Force_Evaluation (Expr); Next (Expr); @@ -2565,25 +3312,27 @@ package body Exp_Util is -- Is_Ref_To_Bit_Packed_Slice -- -------------------------------- - function Is_Ref_To_Bit_Packed_Slice (P : Node_Id) return Boolean is + function Is_Ref_To_Bit_Packed_Slice (N : Node_Id) return Boolean is begin - if Is_Entity_Name (P) - and then Is_Object (Entity (P)) - and then Present (Renamed_Object (Entity (P))) + if Nkind (N) = N_Type_Conversion then + return Is_Ref_To_Bit_Packed_Slice (Expression (N)); + + elsif Is_Entity_Name (N) + and then Is_Object (Entity (N)) + and then Present (Renamed_Object (Entity (N))) then - return Is_Ref_To_Bit_Packed_Slice (Renamed_Object (Entity (P))); - end if; + return Is_Ref_To_Bit_Packed_Slice (Renamed_Object (Entity (N))); - if Nkind (P) = N_Slice - and then Is_Bit_Packed_Array (Etype (Prefix (P))) + elsif Nkind (N) = N_Slice + and then Is_Bit_Packed_Array (Etype (Prefix (N))) then return True; - elsif Nkind (P) = N_Indexed_Component + elsif Nkind (N) = N_Indexed_Component or else - Nkind (P) = N_Selected_Component + Nkind (N) = N_Selected_Component then - return Is_Ref_To_Bit_Packed_Slice (Prefix (P)); + return Is_Ref_To_Bit_Packed_Slice (Prefix (N)); else return False; @@ -2624,19 +3373,22 @@ package body Exp_Util is and then not Is_Tagged_Type (Full_View (T)) and then Is_Derived_Type (Full_View (T)) and then Etype (Full_View (T)) /= T); - end Is_Untagged_Derivation; -------------------- -- Kill_Dead_Code -- -------------------- - procedure Kill_Dead_Code (N : Node_Id) is + procedure Kill_Dead_Code (N : Node_Id; Warn : Boolean := False) is begin if Present (N) then - Remove_Handler_Entries (N); Remove_Warning_Messages (N); + if Warn then + Error_Msg_F + ("?this code can never be executed and has been deleted", N); + end if; + -- Recurse into block statements and bodies to process declarations -- and statements @@ -2644,13 +3396,31 @@ package body Exp_Util is or else Nkind (N) = N_Subprogram_Body or else Nkind (N) = N_Package_Body then - Kill_Dead_Code (Declarations (N)); - Kill_Dead_Code (Statements (Handled_Statement_Sequence (N))); + Kill_Dead_Code + (Declarations (N), False); + Kill_Dead_Code + (Statements (Handled_Statement_Sequence (N))); if Nkind (N) = N_Subprogram_Body then Set_Is_Eliminated (Defining_Entity (N)); end if; + elsif Nkind (N) = N_Package_Declaration then + Kill_Dead_Code (Visible_Declarations (Specification (N))); + Kill_Dead_Code (Private_Declarations (Specification (N))); + + declare + E : Entity_Id := First_Entity (Defining_Entity (N)); + begin + while Present (E) loop + if Ekind (E) = E_Operator then + Set_Is_Eliminated (E); + end if; + + Next_Entity (E); + end loop; + end; + -- Recurse into composite statement to kill individual statements, -- in particular instantiations. @@ -2664,9 +3434,9 @@ package body Exp_Util is elsif Nkind (N) = N_Case_Statement then declare - Alt : Node_Id := First (Alternatives (N)); - + Alt : Node_Id; begin + Alt := First (Alternatives (N)); while Present (Alt) loop Kill_Dead_Code (Statements (Alt)); Next (Alt); @@ -2688,15 +3458,17 @@ package body Exp_Util is -- Case where argument is a list of nodes to be killed - procedure Kill_Dead_Code (L : List_Id) is + procedure Kill_Dead_Code (L : List_Id; Warn : Boolean := False) is N : Node_Id; - + W : Boolean; begin + W := Warn; if Is_Non_Empty_List (L) then loop N := Remove_Head (L); exit when No (N); - Kill_Dead_Code (N); + Kill_Dead_Code (N, W); + W := False; end loop; end if; end Kill_Dead_Code; @@ -2729,27 +3501,38 @@ package body Exp_Util is function Known_Non_Null (N : Node_Id) return Boolean is begin - pragma Assert (Is_Access_Type (Underlying_Type (Etype (N)))); + -- Checks for case where N is an entity reference - -- Case of entity for which Is_Known_Non_Null is True + if Is_Entity_Name (N) and then Present (Entity (N)) then + declare + E : constant Entity_Id := Entity (N); + Op : Node_Kind; + Val : Node_Id; - if Is_Entity_Name (N) and then Is_Known_Non_Null (Entity (N)) then + begin + -- First check if we are in decisive conditional - -- If the entity is aliased or volatile, then we decide that - -- we don't know it is really non-null even if the sequential - -- flow indicates that it is, since such variables can be - -- changed without us noticing. + Get_Current_Value_Condition (N, Op, Val); - if Is_Aliased (Entity (N)) - or else Treat_As_Volatile (Entity (N)) - then - return False; + if Nkind (Val) = N_Null then + if Op = N_Op_Eq then + return False; + elsif Op = N_Op_Ne then + return True; + end if; + end if; - -- For all other cases, the flag is decisive + -- If OK to do replacement, test Is_Known_Non_Null flag - else - return True; - end if; + if OK_To_Do_Constant_Replacement (E) then + return Is_Known_Non_Null (E); + + -- Otherwise if not safe to do replacement, then say so + + else + return False; + end if; + end; -- True if access attribute @@ -2772,26 +3555,70 @@ package body Exp_Util is elsif Nkind (N) = N_Type_Conversion then return Known_Non_Null (Expression (N)); - -- One more case is when Current_Value references a condition - -- that ensures a non-null value. + -- Above are all cases where the value could be determined to be + -- non-null. In all other cases, we don't know, so return False. + + else + return False; + end if; + end Known_Non_Null; + + ---------------- + -- Known_Null -- + ---------------- + + function Known_Null (N : Node_Id) return Boolean is + begin + -- Checks for case where N is an entity reference - elsif Is_Entity_Name (N) then + if Is_Entity_Name (N) and then Present (Entity (N)) then declare + E : constant Entity_Id := Entity (N); Op : Node_Kind; Val : Node_Id; begin + -- First check if we are in decisive conditional + Get_Current_Value_Condition (N, Op, Val); - return Op = N_Op_Ne and then Nkind (Val) = N_Null; + + if Nkind (Val) = N_Null then + if Op = N_Op_Eq then + return True; + elsif Op = N_Op_Ne then + return False; + end if; + end if; + + -- If OK to do replacement, test Is_Known_Null flag + + if OK_To_Do_Constant_Replacement (E) then + return Is_Known_Null (E); + + -- Otherwise if not safe to do replacement, then say so + + else + return False; + end if; end; - -- Above are all cases where the value could be determined to be - -- non-null. In all other cases, we don't know, so return False. + -- True if explicit reference to null + + elsif Nkind (N) = N_Null then + return True; + + -- For a conversion, true if expression is known null + + elsif Nkind (N) = N_Type_Conversion then + return Known_Null (Expression (N)); + + -- Above are all cases where the value could be determined to be null. + -- In all other cases, we don't know, so return False. else return False; end if; - end Known_Non_Null; + end Known_Null; ----------------------------- -- Make_CW_Equivalent_Type -- @@ -2811,13 +3638,13 @@ package body Exp_Util is -- derived types function Make_CW_Equivalent_Type - (T : Entity_Id; - E : Node_Id) - return Entity_Id + (T : Entity_Id; + E : Node_Id) return Entity_Id is Loc : constant Source_Ptr := Sloc (E); Root_Typ : constant Entity_Id := Root_Type (T); List_Def : constant List_Id := Empty_List; + Comp_List : constant List_Id := New_List; Equiv_Type : Entity_Id; Range_Type : Entity_Id; Str_Type : Entity_Id; @@ -2840,22 +3667,35 @@ package body Exp_Util is Make_Subtype_From_Expr (E, Root_Typ))); end if; - -- subtype rg__xx is Storage_Offset range - -- (Expr'size - typ'size) / Storage_Unit + -- Generate the range subtype declaration Range_Type := Make_Defining_Identifier (Loc, New_Internal_Name ('G')); - Sizexpr := - Make_Op_Subtract (Loc, - Left_Opnd => - Make_Attribute_Reference (Loc, - Prefix => - OK_Convert_To (T, Duplicate_Subexpr_No_Checks (E)), - Attribute_Name => Name_Size), - Right_Opnd => - Make_Attribute_Reference (Loc, - Prefix => New_Reference_To (Constr_Root, Loc), - Attribute_Name => Name_Object_Size)); + if not Is_Interface (Root_Typ) then + -- subtype rg__xx is + -- Storage_Offset range 1 .. (Expr'size - typ'size) / Storage_Unit + + Sizexpr := + Make_Op_Subtract (Loc, + Left_Opnd => + Make_Attribute_Reference (Loc, + Prefix => + OK_Convert_To (T, Duplicate_Subexpr_No_Checks (E)), + Attribute_Name => Name_Size), + Right_Opnd => + Make_Attribute_Reference (Loc, + Prefix => New_Reference_To (Constr_Root, Loc), + Attribute_Name => Name_Object_Size)); + else + -- subtype rg__xx is + -- Storage_Offset range 1 .. Expr'size / Storage_Unit + + Sizexpr := + Make_Attribute_Reference (Loc, + Prefix => + OK_Convert_To (T, Duplicate_Subexpr_No_Checks (E)), + Attribute_Name => Name_Size); + end if; Set_Paren_Count (Sizexpr, 1); @@ -2890,7 +3730,7 @@ package body Exp_Util is New_List (New_Reference_To (Range_Type, Loc)))))); -- type Equiv_T is record - -- _parent : Tnn; + -- [ _parent : Tnn; ] -- E : Str_Type; -- end Equiv_T; @@ -2911,36 +3751,41 @@ package body Exp_Util is Set_Ekind (Equiv_Type, E_Record_Type); Set_Parent_Subtype (Equiv_Type, Constr_Root); - Append_To (List_Def, - Make_Full_Type_Declaration (Loc, - Defining_Identifier => Equiv_Type, + if not Is_Interface (Root_Typ) then + Append_To (Comp_List, + Make_Component_Declaration (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, Name_uParent), + Component_Definition => + Make_Component_Definition (Loc, + Aliased_Present => False, + Subtype_Indication => New_Reference_To (Constr_Root, Loc)))); + end if; + + Append_To (Comp_List, + Make_Component_Declaration (Loc, + Defining_Identifier => + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('C')), + Component_Definition => + Make_Component_Definition (Loc, + Aliased_Present => False, + Subtype_Indication => New_Reference_To (Str_Type, Loc)))); + Append_To (List_Def, + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Equiv_Type, Type_Definition => Make_Record_Definition (Loc, - Component_List => Make_Component_List (Loc, - Component_Items => New_List ( - Make_Component_Declaration (Loc, - Defining_Identifier => - Make_Defining_Identifier (Loc, Name_uParent), - Component_Definition => - Make_Component_Definition (Loc, - Aliased_Present => False, - Subtype_Indication => - New_Reference_To (Constr_Root, Loc))), - - Make_Component_Declaration (Loc, - Defining_Identifier => - Make_Defining_Identifier (Loc, - Chars => New_Internal_Name ('C')), - Component_Definition => - Make_Component_Definition (Loc, - Aliased_Present => False, - Subtype_Indication => - New_Reference_To (Str_Type, Loc)))), - - Variant_Part => Empty)))); - - Insert_Actions (E, List_Def); + Component_List => + Make_Component_List (Loc, + Component_Items => Comp_List, + Variant_Part => Empty)))); + + -- Suppress all checks during the analysis of the expanded code + -- to avoid the generation of spurious warnings under ZFP run-time. + + Insert_Actions (E, List_Def, Suppress => All_Checks); return Equiv_Type; end Make_CW_Equivalent_Type; @@ -2950,8 +3795,7 @@ package body Exp_Util is function Make_Literal_Range (Loc : Source_Ptr; - Literal_Typ : Entity_Id) - return Node_Id + Literal_Typ : Entity_Id) return Node_Id is Lo : constant Node_Id := New_Copy_Tree (String_Literal_Low_Bound (Literal_Typ)); @@ -2988,8 +3832,7 @@ package body Exp_Util is function Make_Subtype_From_Expr (E : Node_Id; - Unc_Typ : Entity_Id) - return Node_Id + Unc_Typ : Entity_Id) return Node_Id is Loc : constant Source_Ptr := Sloc (E); List_Constr : constant List_Id := New_List; @@ -3005,7 +3848,8 @@ package body Exp_Util is and then Has_Unknown_Discriminants (Unc_Typ) then -- Prepare the subtype completion, Go to base type to - -- find underlying type. + -- find underlying type, because the type may be a generic + -- actual or an explicit subtype. Utyp := Underlying_Type (Base_Type (Unc_Typ)); Full_Subtyp := Make_Defining_Identifier (Loc, @@ -3026,7 +3870,7 @@ package body Exp_Util is -- Define the dummy private subtype Set_Ekind (Priv_Subtyp, Subtype_Kind (Ekind (Unc_Typ))); - Set_Etype (Priv_Subtyp, Unc_Typ); + Set_Etype (Priv_Subtyp, Base_Type (Unc_Typ)); Set_Scope (Priv_Subtyp, Full_Subtyp); Set_Is_Constrained (Priv_Subtyp); Set_Is_Tagged_Type (Priv_Subtyp, Is_Tagged_Type (Unc_Typ)); @@ -3069,12 +3913,12 @@ package body Exp_Util is EQ_Typ : Entity_Id := Empty; begin - -- A class-wide equivalent type is not needed when Java_VM - -- because the JVM back end handles the class-wide object + -- A class-wide equivalent type is not needed when VM_Target + -- because the VM back-ends handle the class-wide object -- initialization itself (and doesn't need or want the -- additional intermediate type to handle the assignment). - if Expander_Active and then not Java_VM then + if Expander_Active and then VM_Target = No_VM then EQ_Typ := Make_CW_Equivalent_Type (Unc_Typ, E); end if; @@ -3090,7 +3934,7 @@ package body Exp_Util is return New_Occurrence_Of (CW_Subtype, Loc); end; - -- Comment needed (what case is this ???) + -- Indefinite record type with discriminants else D := First_Discriminant (Unc_Typ); @@ -3118,7 +3962,7 @@ package body Exp_Util is -- At the current time, the only types that we return False for (i.e. -- where we decide we know they cannot generate large temps) are ones - -- where we know the size is 128 bits or less at compile time, and we + -- where we know the size is 256 bits or less at compile time, and we -- are still not doing a thorough job on arrays and records ??? function May_Generate_Large_Temp (Typ : Entity_Id) return Boolean is @@ -3147,8 +3991,7 @@ package body Exp_Util is function New_Class_Wide_Subtype (CW_Typ : Entity_Id; - N : Node_Id) - return Entity_Id + N : Node_Id) return Entity_Id is Res : constant Entity_Id := Create_Itype (E_Void, N); Res_Name : constant Name_Id := Chars (Res); @@ -3156,6 +3999,7 @@ package body Exp_Util is begin Copy_Node (CW_Typ, Res); + Set_Comes_From_Source (Res, False); Set_Sloc (Res, Sloc (N)); Set_Is_Itype (Res); Set_Associated_Node_For_Itype (Res, N); @@ -3182,6 +4026,152 @@ package body Exp_Util is return (Res); end New_Class_Wide_Subtype; + -------------------------------- + -- Non_Limited_Designated_Type -- + --------------------------------- + + function Non_Limited_Designated_Type (T : Entity_Id) return Entity_Id is + Desig : constant Entity_Id := Designated_Type (T); + begin + if Ekind (Desig) = E_Incomplete_Type + and then Present (Non_Limited_View (Desig)) + then + return Non_Limited_View (Desig); + else + return Desig; + end if; + end Non_Limited_Designated_Type; + + ----------------------------------- + -- OK_To_Do_Constant_Replacement -- + ----------------------------------- + + function OK_To_Do_Constant_Replacement (E : Entity_Id) return Boolean is + ES : constant Entity_Id := Scope (E); + CS : Entity_Id; + + begin + -- Do not replace statically allocated objects, because they may be + -- modified outside the current scope. + + if Is_Statically_Allocated (E) then + return False; + + -- Do not replace aliased or volatile objects, since we don't know what + -- else might change the value. + + elsif Is_Aliased (E) or else Treat_As_Volatile (E) then + return False; + + -- Debug flag -gnatdM disconnects this optimization + + elsif Debug_Flag_MM then + return False; + + -- Otherwise check scopes + + else + CS := Current_Scope; + + loop + -- If we are in right scope, replacement is safe + + if CS = ES then + return True; + + -- Packages do not affect the determination of safety + + elsif Ekind (CS) = E_Package then + exit when CS = Standard_Standard; + CS := Scope (CS); + + -- Blocks do not affect the determination of safety + + elsif Ekind (CS) = E_Block then + CS := Scope (CS); + + -- Loops do not affect the determination of safety. Note that we + -- kill all current values on entry to a loop, so we are just + -- talking about processing within a loop here. + + elsif Ekind (CS) = E_Loop then + CS := Scope (CS); + + -- Otherwise, the reference is dubious, and we cannot be sure that + -- it is safe to do the replacement. + + else + exit; + end if; + end loop; + + return False; + end if; + end OK_To_Do_Constant_Replacement; + + ------------------------------------ + -- Possible_Bit_Aligned_Component -- + ------------------------------------ + + function Possible_Bit_Aligned_Component (N : Node_Id) return Boolean is + begin + case Nkind (N) is + + -- Case of indexed component + + when N_Indexed_Component => + declare + P : constant Node_Id := Prefix (N); + Ptyp : constant Entity_Id := Etype (P); + + begin + -- If we know the component size and it is less than 64, then + -- we are definitely OK. The back end always does assignment + -- of misaligned small objects correctly. + + if Known_Static_Component_Size (Ptyp) + and then Component_Size (Ptyp) <= 64 + then + return False; + + -- Otherwise, we need to test the prefix, to see if we are + -- indexing from a possibly unaligned component. + + else + return Possible_Bit_Aligned_Component (P); + end if; + end; + + -- Case of selected component + + when N_Selected_Component => + declare + P : constant Node_Id := Prefix (N); + Comp : constant Entity_Id := Entity (Selector_Name (N)); + + begin + -- If there is no component clause, then we are in the clear + -- since the back end will never misalign a large component + -- unless it is forced to do so. In the clear means we need + -- only the recursive test on the prefix. + + if Component_May_Be_Bit_Aligned (Comp) then + return True; + else + return Possible_Bit_Aligned_Component (P); + end if; + end; + + -- If we have neither a record nor array component, it means that we + -- have fallen off the top testing prefixes recursively, and we now + -- have a stand alone object, where we don't have a problem. + + when others => + return False; + + end case; + end Possible_Bit_Aligned_Component; + ------------------------- -- Remove_Side_Effects -- ------------------------- @@ -3191,7 +4181,7 @@ package body Exp_Util is Name_Req : Boolean := False; Variable_Ref : Boolean := False) is - Loc : constant Source_Ptr := Sloc (Exp); + Loc : constant Source_Ptr := Sloc (Exp); Exp_Type : constant Entity_Id := Etype (Exp); Svg_Suppress : constant Suppress_Array := Scope_Suppress; Def_Id : Entity_Id; @@ -3202,31 +4192,30 @@ package body Exp_Util is E : Node_Id; function Side_Effect_Free (N : Node_Id) return Boolean; - -- Determines if the tree N represents an expession that is known - -- not to have side effects, and for which no processing is required. + -- Determines if the tree N represents an expression that is known not + -- to have side effects, and for which no processing is required. function Side_Effect_Free (L : List_Id) return Boolean; -- Determines if all elements of the list L are side effect free function Safe_Prefixed_Reference (N : Node_Id) return Boolean; - -- The argument N is a construct where the Prefix is dereferenced - -- if it is a an access type and the result is a variable. The call - -- returns True if the construct is side effect free (not considering - -- side effects in other than the prefix which are to be tested by the - -- caller). + -- The argument N is a construct where the Prefix is dereferenced if it + -- is an access type and the result is a variable. The call returns True + -- if the construct is side effect free (not considering side effects in + -- other than the prefix which are to be tested by the caller). function Within_In_Parameter (N : Node_Id) return Boolean; - -- Determines if N is a subcomponent of a composite in-parameter. - -- If so, N is not side-effect free when the actual is global and - -- modifiable indirectly from within a subprogram, because it may - -- be passed by reference. The front-end must be conservative here - -- and assume that this may happen with any array or record type. - -- On the other hand, we cannot create temporaries for all expressions - -- for which this condition is true, for various reasons that might - -- require clearing up ??? For example, descriminant references that - -- appear out of place, or spurious type errors with class-wide - -- expressions. As a result, we limit the transformation to loop - -- bounds, which is so far the only case that requires it. + -- Determines if N is a subcomponent of a composite in-parameter. If so, + -- N is not side-effect free when the actual is global and modifiable + -- indirectly from within a subprogram, because it may be passed by + -- reference. The front-end must be conservative here and assume that + -- this may happen with any array or record type. On the other hand, we + -- cannot create temporaries for all expressions for which this + -- condition is true, for various reasons that might require clearing up + -- ??? For example, descriminant references that appear out of place, or + -- spurious type errors with class-wide expressions. As a result, we + -- limit the transformation to loop bounds, which is so far the only + -- case that requires it. ----------------------------- -- Safe_Prefixed_Reference -- @@ -3335,6 +4324,17 @@ package body Exp_Util is elsif Compile_Time_Known_Value (N) then return True; + + -- A variable renaming is not side-effet free, because the + -- renaming will function like a macro in the front-end in + -- some cases, and an assignment can modify the the component + -- designated by N, so we need to create a temporary for it. + + elsif Is_Entity_Name (Original_Node (N)) + and then Is_Renaming_Of_Object (Entity (Original_Node (N))) + and then Ekind (Entity (Original_Node (N))) /= E_Constant + then + return False; end if; -- For other than entity names and compile time known values, @@ -3350,6 +4350,7 @@ package body Exp_Util is when N_Attribute_Reference => return Side_Effect_Free (Expressions (N)) + and then Attribute_Name (N) /= Name_Input and then (Is_Entity_Name (Prefix (N)) or else Side_Effect_Free (Prefix (N))); @@ -3357,11 +4358,10 @@ package body Exp_Util is -- are side effect free. For this purpose binary operators -- include membership tests and short circuit forms - when N_Binary_Op | - N_In | - N_Not_In | - N_And_Then | - N_Or_Else => + when N_Binary_Op | + N_Membership_Test | + N_And_Then | + N_Or_Else => return Side_Effect_Free (Left_Opnd (N)) and then Side_Effect_Free (Right_Opnd (N)); @@ -3474,7 +4474,6 @@ package body Exp_Util is else N := First (L); - while Present (N) loop if not Side_Effect_Free (N) then return False; @@ -3524,10 +4523,37 @@ package body Exp_Util is Scope_Suppress := (others => True); + -- If it is a scalar type and we need to capture the value, just + -- make a copy. Likewise for a function call. And if we have a + -- volatile variable and Nam_Req is not set (see comments above + -- for Side_Effect_Free). + + if Is_Elementary_Type (Exp_Type) + and then (Variable_Ref + or else Nkind (Exp) = N_Function_Call + or else (not Name_Req + and then Is_Entity_Name (Exp) + and then Treat_As_Volatile (Entity (Exp)))) + then + + Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); + Set_Etype (Def_Id, Exp_Type); + Res := New_Reference_To (Def_Id, Loc); + + E := + Make_Object_Declaration (Loc, + Defining_Identifier => Def_Id, + Object_Definition => New_Reference_To (Exp_Type, Loc), + Constant_Present => True, + Expression => Relocate_Node (Exp)); + + Set_Assignment_OK (E); + Insert_Action (Exp, E); + -- If the expression has the form v.all then we can just capture -- the pointer, and then do an explicit dereference on the result. - if Nkind (Exp) = N_Explicit_Dereference then + elsif Nkind (Exp) = N_Explicit_Dereference then Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); Res := @@ -3547,7 +4573,7 @@ package body Exp_Util is elsif Nkind (Exp) = N_Unchecked_Type_Conversion and then Nkind (Expression (Exp)) = N_Explicit_Dereference then - Remove_Side_Effects (Expression (Exp), Variable_Ref); + Remove_Side_Effects (Expression (Exp), Name_Req, Variable_Ref); Scope_Suppress := Svg_Suppress; return; @@ -3555,46 +4581,64 @@ package body Exp_Util is -- the side effects in the expression. This is important in several -- circumstances: for change of representations, and also when this -- is a view conversion to a smaller object, where gigi can end up - -- its own temporary of the wrong size. - - -- ??? this transformation is inhibited for elementary types that are - -- not involved in a change of representation because it causes - -- regressions that are not fully understood yet. + -- creating its own temporary of the wrong size. - elsif Nkind (Exp) = N_Type_Conversion - and then (not Is_Elementary_Type (Underlying_Type (Exp_Type)) - or else Nkind (Parent (Exp)) = N_Assignment_Statement) - then - Remove_Side_Effects (Expression (Exp), Variable_Ref); + elsif Nkind (Exp) = N_Type_Conversion then + Remove_Side_Effects (Expression (Exp), Name_Req, Variable_Ref); Scope_Suppress := Svg_Suppress; return; + -- If this is an unchecked conversion that Gigi can't handle, make + -- a copy or a use a renaming to capture the value. + + elsif Nkind (Exp) = N_Unchecked_Type_Conversion + and then not Safe_Unchecked_Type_Conversion (Exp) + then + if CW_Or_Controlled_Type (Exp_Type) then + + -- Use a renaming to capture the expression, rather than create + -- a controlled temporary. + + Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); + Res := New_Reference_To (Def_Id, Loc); + + Insert_Action (Exp, + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Def_Id, + Subtype_Mark => New_Reference_To (Exp_Type, Loc), + Name => Relocate_Node (Exp))); + + else + Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); + Set_Etype (Def_Id, Exp_Type); + Res := New_Reference_To (Def_Id, Loc); + + E := + Make_Object_Declaration (Loc, + Defining_Identifier => Def_Id, + Object_Definition => New_Reference_To (Exp_Type, Loc), + Constant_Present => not Is_Variable (Exp), + Expression => Relocate_Node (Exp)); + + Set_Assignment_OK (E); + Insert_Action (Exp, E); + end if; + -- For expressions that denote objects, we can use a renaming scheme. -- We skip using this if we have a volatile variable and we do not -- have Nam_Req set true (see comments above for Side_Effect_Free). - -- We also skip this scheme for class-wide expressions in order to - -- avoid recursive expansion (see Expand_N_Object_Renaming_Declaration) - -- If the object is a function call, we need to create a temporary and - -- not a renaming. - - -- Note that we could use ordinary object declarations in the case of - -- expressions not appearing as lvalues. That is left as a possible - -- optimization in the future but we prefer to generate renamings - -- right now, since we may indeed be transforming an lvalue. elsif Is_Object_Reference (Exp) and then Nkind (Exp) /= N_Function_Call - and then not Variable_Ref and then (Name_Req or else not Is_Entity_Name (Exp) or else not Treat_As_Volatile (Entity (Exp))) - and then not Is_Class_Wide_Type (Exp_Type) then Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); if Nkind (Exp) = N_Selected_Component and then Nkind (Prefix (Exp)) = N_Function_Call - and then Is_Array_Type (Etype (Exp)) + and then Is_Array_Type (Exp_Type) then -- Avoid generating a variable-sized temporary, by generating -- the renaming declaration just for the function call. The @@ -3613,12 +4657,6 @@ package body Exp_Util is New_Reference_To (Base_Type (Etype (Prefix (Exp))), Loc), Name => Relocate_Node (Prefix (Exp)))); - -- The temporary must be elaborated by gigi, and is of course - -- not to be replaced in-line by the expression it renames, - -- which would defeat the purpose of removing the side-effect. - - Set_Is_Renaming_Of_Object (Def_Id, False); - else Res := New_Reference_To (Def_Id, Loc); @@ -3628,61 +4666,23 @@ package body Exp_Util is Subtype_Mark => New_Reference_To (Exp_Type, Loc), Name => Relocate_Node (Exp))); - Set_Is_Renaming_Of_Object (Def_Id, False); end if; - -- If it is a scalar type, just make a copy. - - elsif Is_Elementary_Type (Exp_Type) then - Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); - Set_Etype (Def_Id, Exp_Type); - Res := New_Reference_To (Def_Id, Loc); - - E := - Make_Object_Declaration (Loc, - Defining_Identifier => Def_Id, - Object_Definition => New_Reference_To (Exp_Type, Loc), - Constant_Present => True, - Expression => Relocate_Node (Exp)); - - Set_Assignment_OK (E); - Insert_Action (Exp, E); - - -- Always use a renaming for an unchecked conversion - -- If this is an unchecked conversion that Gigi can't handle, make - -- a copy or a use a renaming to capture the value. - - elsif Nkind (Exp) = N_Unchecked_Type_Conversion - and then not Safe_Unchecked_Type_Conversion (Exp) - then - if Controlled_Type (Etype (Exp)) then - - -- Use a renaming to capture the expression, rather than create - -- a controlled temporary. - - Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); - Res := New_Reference_To (Def_Id, Loc); - - Insert_Action (Exp, - Make_Object_Renaming_Declaration (Loc, - Defining_Identifier => Def_Id, - Subtype_Mark => New_Reference_To (Exp_Type, Loc), - Name => Relocate_Node (Exp))); - + -- If this is a packed reference, or a selected component with a + -- non-standard representation, a reference to the temporary will + -- be replaced by a copy of the original expression (see + -- exp_ch2.Expand_Renaming). Otherwise the temporary must be + -- elaborated by gigi, and is of course not to be replaced in-line + -- by the expression it renames, which would defeat the purpose of + -- removing the side-effect. + + if (Nkind (Exp) = N_Selected_Component + or else Nkind (Exp) = N_Indexed_Component) + and then Has_Non_Standard_Rep (Etype (Prefix (Exp))) + then + null; else - Def_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); - Set_Etype (Def_Id, Exp_Type); - Res := New_Reference_To (Def_Id, Loc); - - E := - Make_Object_Declaration (Loc, - Defining_Identifier => Def_Id, - Object_Definition => New_Reference_To (Exp_Type, Loc), - Constant_Present => not Is_Variable (Exp), - Expression => Relocate_Node (Exp)); - - Set_Assignment_OK (E); - Insert_Action (Exp, E); + Set_Is_Renaming_Of_Object (Def_Id, False); end if; -- Otherwise we generate a reference to the value @@ -3716,8 +4716,22 @@ package body Exp_Util is New_Exp := Make_Reference (Loc, E); end if; - if Nkind (E) = N_Aggregate and then Expansion_Delayed (E) then - Set_Expansion_Delayed (E, False); + if Is_Delayed_Aggregate (E) then + + -- The expansion of nested aggregates is delayed until the + -- enclosing aggregate is expanded. As aggregates are often + -- qualified, the predicate applies to qualified expressions + -- as well, indicating that the enclosing aggregate has not + -- been expanded yet. At this point the aggregate is part of + -- a stand-alone declaration, and must be fully expanded. + + if Nkind (E) = N_Qualified_Expression then + Set_Expansion_Delayed (Expression (E), False); + Set_Analyzed (Expression (E), False); + else + Set_Expansion_Delayed (E, False); + end if; + Set_Analyzed (E, False); end if; @@ -3741,6 +4755,18 @@ package body Exp_Util is Scope_Suppress := Svg_Suppress; end Remove_Side_Effects; + --------------------------- + -- Represented_As_Scalar -- + --------------------------- + + function Represented_As_Scalar (T : Entity_Id) return Boolean is + UT : constant Entity_Id := Underlying_Type (T); + begin + return Is_Scalar_Type (UT) + or else (Is_Bit_Packed_Array (UT) + and then Is_Scalar_Type (Packed_Array_Type (UT))); + end Represented_As_Scalar; + ------------------------------------ -- Safe_Unchecked_Type_Conversion -- ------------------------------------ @@ -3839,6 +4865,16 @@ package body Exp_Util is if Implementation_Base_Type (Otyp) = Implementation_Base_Type (Ityp) then return True; + -- Same if this is an upwards conversion of an untagged type, and there + -- are no constraints involved (could be more general???) + + elsif Etype (Ityp) = Otyp + and then not Is_Tagged_Type (Ityp) + and then not Has_Discriminants (Ityp) + and then No (First_Rep_Item (Base_Type (Ityp))) + then + return True; + -- If the size of output type is known at compile time, there is -- never a problem. Note that unconstrained records are considered -- to be of known size, but we can't consider them that way here, @@ -3912,14 +4948,118 @@ package body Exp_Util is then return True; - -- Otherwise, Gigi cannot handle this and we must make a temporary. + -- Otherwise, Gigi cannot handle this and we must make a temporary else return False; end if; - end Safe_Unchecked_Type_Conversion; + --------------------------------- + -- Set_Current_Value_Condition -- + --------------------------------- + + -- Note: the implementation of this procedure is very closely tied to the + -- implementation of Get_Current_Value_Condition. Here we set required + -- Current_Value fields, and in Get_Current_Value_Condition, we interpret + -- them, so they must have a consistent view. + + procedure Set_Current_Value_Condition (Cnode : Node_Id) is + + procedure Set_Entity_Current_Value (N : Node_Id); + -- If N is an entity reference, where the entity is of an appropriate + -- kind, then set the current value of this entity to Cnode, unless + -- there is already a definite value set there. + + procedure Set_Expression_Current_Value (N : Node_Id); + -- If N is of an appropriate form, sets an appropriate entry in current + -- value fields of relevant entities. Multiple entities can be affected + -- in the case of an AND or AND THEN. + + ------------------------------ + -- Set_Entity_Current_Value -- + ------------------------------ + + procedure Set_Entity_Current_Value (N : Node_Id) is + begin + if Is_Entity_Name (N) then + declare + Ent : constant Entity_Id := Entity (N); + + begin + -- Don't capture if not safe to do so + + if not Safe_To_Capture_Value (N, Ent, Cond => True) then + return; + end if; + + -- Here we have a case where the Current_Value field may + -- need to be set. We set it if it is not already set to a + -- compile time expression value. + + -- Note that this represents a decision that one condition + -- blots out another previous one. That's certainly right + -- if they occur at the same level. If the second one is + -- nested, then the decision is neither right nor wrong (it + -- would be equally OK to leave the outer one in place, or + -- take the new inner one. Really we should record both, but + -- our data structures are not that elaborate. + + if Nkind (Current_Value (Ent)) not in N_Subexpr then + Set_Current_Value (Ent, Cnode); + end if; + end; + end if; + end Set_Entity_Current_Value; + + ---------------------------------- + -- Set_Expression_Current_Value -- + ---------------------------------- + + procedure Set_Expression_Current_Value (N : Node_Id) is + Cond : Node_Id; + + begin + Cond := N; + + -- Loop to deal with (ignore for now) any NOT operators present. The + -- presence of NOT operators will be handled properly when we call + -- Get_Current_Value_Condition. + + while Nkind (Cond) = N_Op_Not loop + Cond := Right_Opnd (Cond); + end loop; + + -- For an AND or AND THEN, recursively process operands + + if Nkind (Cond) = N_Op_And or else Nkind (Cond) = N_And_Then then + Set_Expression_Current_Value (Left_Opnd (Cond)); + Set_Expression_Current_Value (Right_Opnd (Cond)); + return; + end if; + + -- Check possible relational operator + + if Nkind (Cond) in N_Op_Compare then + if Compile_Time_Known_Value (Right_Opnd (Cond)) then + Set_Entity_Current_Value (Left_Opnd (Cond)); + elsif Compile_Time_Known_Value (Left_Opnd (Cond)) then + Set_Entity_Current_Value (Right_Opnd (Cond)); + end if; + + -- Check possible boolean variable reference + + else + Set_Entity_Current_Value (Cond); + end if; + end Set_Expression_Current_Value; + + -- Start of processing for Set_Current_Value_Condition + + begin + Set_Expression_Current_Value (Condition (Cnode)); + end Set_Current_Value_Condition; + -------------------------- -- Set_Elaboration_Flag -- -------------------------- @@ -3964,6 +5104,32 @@ package body Exp_Util is end if; end Set_Elaboration_Flag; + ---------------------------- + -- Set_Renamed_Subprogram -- + ---------------------------- + + procedure Set_Renamed_Subprogram (N : Node_Id; E : Entity_Id) is + begin + -- If input node is an identifier, we can just reset it + + if Nkind (N) = N_Identifier then + Set_Chars (N, Chars (E)); + Set_Entity (N, E); + + -- Otherwise we have to do a rewrite, preserving Comes_From_Source + + else + declare + CS : constant Boolean := Comes_From_Source (N); + begin + Rewrite (N, Make_Identifier (Sloc (N), Chars => Chars (E))); + Set_Entity (N, E); + Set_Comes_From_Source (N, CS); + Set_Analyzed (N, True); + end; + end if; + end Set_Renamed_Subprogram; + -------------------------- -- Target_Has_Fixed_Ops -- -------------------------- @@ -3982,8 +5148,7 @@ package body Exp_Util is function Target_Has_Fixed_Ops (Left_Typ : Entity_Id; Right_Typ : Entity_Id; - Result_Typ : Entity_Id) - return Boolean + Result_Typ : Entity_Id) return Boolean is function Is_Fractional_Type (Typ : Entity_Id) return Boolean; -- Return True if the given type is a fixed-point type with a small @@ -4068,20 +5233,15 @@ package body Exp_Util is E : Entity_Id; begin - E := First_Entity (Typ); + E := First_Component_Or_Discriminant (Typ); while Present (E) loop - if Ekind (E) = E_Component - or else Ekind (E) = E_Discriminant + if Component_May_Be_Bit_Aligned (E) + or else Type_May_Have_Bit_Aligned_Components (Etype (E)) then - if Component_May_Be_Bit_Aligned (E) - or else - Type_May_Have_Bit_Aligned_Components (Etype (E)) - then - return True; - end if; + return True; end if; - Next_Entity (E); + Next_Component_Or_Discriminant (E); end loop; return False;