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diff --git a/gcc/ada/exp_ch6.adb b/gcc/ada/exp_ch6.adb new file mode 100644 index 00000000000..e15328519cb --- /dev/null +++ b/gcc/ada/exp_ch6.adb @@ -0,0 +1,3227 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- E X P _ C H 6 -- +-- -- +-- B o d y -- +-- -- +-- $Revision: 1.343 $ +-- -- +-- Copyright (C) 1992-2001, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 2, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING. If not, write -- +-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- +-- MA 02111-1307, USA. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +with Atree; use Atree; +with Checks; use Checks; +with Debug; use Debug; +with Einfo; use Einfo; +with Errout; use Errout; +with Elists; use Elists; +with Exp_Ch2; use Exp_Ch2; +with Exp_Ch3; use Exp_Ch3; +with Exp_Ch7; use Exp_Ch7; +with Exp_Ch9; use Exp_Ch9; +with Exp_Ch11; use Exp_Ch11; +with Exp_Dbug; use Exp_Dbug; +with Exp_Disp; use Exp_Disp; +with Exp_Dist; use Exp_Dist; +with Exp_Intr; use Exp_Intr; +with Exp_Pakd; use Exp_Pakd; +with Exp_Tss; use Exp_Tss; +with Exp_Util; use Exp_Util; +with Freeze; use Freeze; +with Hostparm; use Hostparm; +with Inline; use Inline; +with Lib; use Lib; +with Nlists; use Nlists; +with Nmake; use Nmake; +with Opt; use Opt; +with Restrict; use Restrict; +with Rtsfind; use Rtsfind; +with Sem; use Sem; +with Sem_Ch6; use Sem_Ch6; +with Sem_Ch8; use Sem_Ch8; +with Sem_Ch12; use Sem_Ch12; +with Sem_Ch13; use Sem_Ch13; +with Sem_Disp; use Sem_Disp; +with Sem_Dist; use Sem_Dist; +with Sem_Res; use Sem_Res; +with Sem_Util; use Sem_Util; +with Sinfo; use Sinfo; +with Snames; use Snames; +with Stand; use Stand; +with Tbuild; use Tbuild; +with Uintp; use Uintp; +with Validsw; use Validsw; + +package body Exp_Ch6 is + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Check_Overriding_Operation (Subp : Entity_Id); + -- Subp is a dispatching operation. Check whether it may override an + -- inherited private operation, in which case its DT entry is that of + -- the hidden operation, not the one it may have received earlier. + -- This must be done before emitting the code to set the corresponding + -- DT to the address of the subprogram. The actual placement of Subp in + -- the proper place in the list of primitive operations is done in + -- Declare_Inherited_Private_Subprograms, which also has to deal with + -- implicit operations. This duplication is unavoidable for now??? + + procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id); + -- This procedure is called only if the subprogram body N, whose spec + -- has the given entity Spec, contains a parameterless recursive call. + -- It attempts to generate runtime code to detect if this a case of + -- infinite recursion. + -- + -- The body is scanned to determine dependencies. If the only external + -- dependencies are on a small set of scalar variables, then the values + -- of these variables are captured on entry to the subprogram, and if + -- the values are not changed for the call, we know immediately that + -- we have an infinite recursion. + + procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id); + -- For each actual of an in-out parameter which is a numeric conversion + -- of the form T(A), where A denotes a variable, we insert the declaration: + -- + -- Temp : T := T(A); + -- + -- prior to the call. Then we replace the actual with a reference to Temp, + -- and append the assignment: + -- + -- A := T' (Temp); + -- + -- after the call. Here T' is the actual type of variable A. + -- For out parameters, the initial declaration has no expression. + -- If A is not an entity name, we generate instead: + -- + -- Var : T' renames A; + -- Temp : T := Var; -- omitting expression for out parameter. + -- ... + -- Var := T' (Temp); + -- + -- For other in-out parameters, we emit the required constraint checks + -- before and/or after the call. + + -- For all parameter modes, actuals that denote components and slices + -- of packed arrays are expanded into suitable temporaries. + + procedure Expand_Inlined_Call + (N : Node_Id; + Subp : Entity_Id; + Orig_Subp : Entity_Id); + -- If called subprogram can be inlined by the front-end, retrieve the + -- analyzed body, replace formals with actuals and expand call in place. + -- Generate thunks for actuals that are expressions, and insert the + -- corresponding constant declarations before the call. If the original + -- call is to a derived operation, the return type is the one of the + -- derived operation, but the body is that of the original, so return + -- expressions in the body must be converted to the desired type (which + -- is simply not noted in the tree without inline expansion). + + function Expand_Protected_Object_Reference + (N : Node_Id; + Scop : Entity_Id) + return Node_Id; + + procedure Expand_Protected_Subprogram_Call + (N : Node_Id; + Subp : Entity_Id; + Scop : Entity_Id); + -- A call to a protected subprogram within the protected object may appear + -- as a regular call. The list of actuals must be expanded to contain a + -- reference to the object itself, and the call becomes a call to the + -- corresponding protected subprogram. + + --------------------------------- + -- Check_Overriding_Operation -- + --------------------------------- + + procedure Check_Overriding_Operation (Subp : Entity_Id) is + Typ : constant Entity_Id := Find_Dispatching_Type (Subp); + Op_List : constant Elist_Id := Primitive_Operations (Typ); + Op_Elmt : Elmt_Id; + Prim_Op : Entity_Id; + Par_Op : Entity_Id; + + begin + if Is_Derived_Type (Typ) + and then not Is_Private_Type (Typ) + and then In_Open_Scopes (Scope (Etype (Typ))) + and then Typ = Base_Type (Typ) + then + -- Subp overrides an inherited private operation if there is + -- an inherited operation with a different name than Subp (see + -- Derive_Subprogram) whose Alias is a hidden subprogram with + -- the same name as Subp. + + Op_Elmt := First_Elmt (Op_List); + while Present (Op_Elmt) loop + Prim_Op := Node (Op_Elmt); + Par_Op := Alias (Prim_Op); + + if Present (Par_Op) + and then not Comes_From_Source (Prim_Op) + and then Chars (Prim_Op) /= Chars (Par_Op) + and then Chars (Par_Op) = Chars (Subp) + and then Is_Hidden (Par_Op) + and then Type_Conformant (Prim_Op, Subp) + then + Set_DT_Position (Subp, DT_Position (Prim_Op)); + end if; + + Next_Elmt (Op_Elmt); + end loop; + end if; + end Check_Overriding_Operation; + + ------------------------------- + -- Detect_Infinite_Recursion -- + ------------------------------- + + procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id) is + Loc : constant Source_Ptr := Sloc (N); + + Var_List : Elist_Id := New_Elmt_List; + -- List of globals referenced by body of procedure + + Call_List : Elist_Id := New_Elmt_List; + -- List of recursive calls in body of procedure + + Shad_List : Elist_Id := New_Elmt_List; + -- List of entity id's for entities created to capture the + -- value of referenced globals on entry to the procedure. + + Scop : constant Uint := Scope_Depth (Spec); + -- This is used to record the scope depth of the current + -- procedure, so that we can identify global references. + + Max_Vars : constant := 4; + -- Do not test more than four global variables + + Count_Vars : Natural := 0; + -- Count variables found so far + + Var : Entity_Id; + Elm : Elmt_Id; + Ent : Entity_Id; + Call : Elmt_Id; + Decl : Node_Id; + Test : Node_Id; + Elm1 : Elmt_Id; + Elm2 : Elmt_Id; + Last : Node_Id; + + function Process (Nod : Node_Id) return Traverse_Result; + -- Function to traverse the subprogram body (using Traverse_Func) + + ------------- + -- Process -- + ------------- + + function Process (Nod : Node_Id) return Traverse_Result is + begin + -- Procedure call + + if Nkind (Nod) = N_Procedure_Call_Statement then + + -- Case of one of the detected recursive calls + + if Is_Entity_Name (Name (Nod)) + and then Has_Recursive_Call (Entity (Name (Nod))) + and then Entity (Name (Nod)) = Spec + then + Append_Elmt (Nod, Call_List); + return Skip; + + -- Any other procedure call may have side effects + + else + return Abandon; + end if; + + -- A call to a pure function can always be ignored + + elsif Nkind (Nod) = N_Function_Call + and then Is_Entity_Name (Name (Nod)) + and then Is_Pure (Entity (Name (Nod))) + then + return Skip; + + -- Case of an identifier reference + + elsif Nkind (Nod) = N_Identifier then + Ent := Entity (Nod); + + -- If no entity, then ignore the reference + + -- Not clear why this can happen. To investigate, remove this + -- test and look at the crash that occurs here in 3401-004 ??? + + if No (Ent) then + return Skip; + + -- Ignore entities with no Scope, again not clear how this + -- can happen, to investigate, look at 4108-008 ??? + + elsif No (Scope (Ent)) then + return Skip; + + -- Ignore the reference if not to a more global object + + elsif Scope_Depth (Scope (Ent)) >= Scop then + return Skip; + + -- References to types, exceptions and constants are always OK + + elsif Is_Type (Ent) + or else Ekind (Ent) = E_Exception + or else Ekind (Ent) = E_Constant + then + return Skip; + + -- If other than a non-volatile scalar variable, we have some + -- kind of global reference (e.g. to a function) that we cannot + -- deal with so we forget the attempt. + + elsif Ekind (Ent) /= E_Variable + or else not Is_Scalar_Type (Etype (Ent)) + or else Is_Volatile (Ent) + then + return Abandon; + + -- Otherwise we have a reference to a global scalar + + else + -- Loop through global entities already detected + + Elm := First_Elmt (Var_List); + loop + -- If not detected before, record this new global reference + + if No (Elm) then + Count_Vars := Count_Vars + 1; + + if Count_Vars <= Max_Vars then + Append_Elmt (Entity (Nod), Var_List); + else + return Abandon; + end if; + + exit; + + -- If recorded before, ignore + + elsif Node (Elm) = Entity (Nod) then + return Skip; + + -- Otherwise keep looking + + else + Next_Elmt (Elm); + end if; + end loop; + + return Skip; + end if; + + -- For all other node kinds, recursively visit syntactic children + + else + return OK; + end if; + end Process; + + function Traverse_Body is new Traverse_Func; + + -- Start of processing for Detect_Infinite_Recursion + + begin + -- Do not attempt detection in No_Implicit_Conditional mode, + -- since we won't be able to generate the code to handle the + -- recursion in any case. + + if Restrictions (No_Implicit_Conditionals) then + return; + end if; + + -- Otherwise do traversal and quit if we get abandon signal + + if Traverse_Body (N) = Abandon then + return; + + -- We must have a call, since Has_Recursive_Call was set. If not + -- just ignore (this is only an error check, so if we have a funny + -- situation, due to bugs or errors, we do not want to bomb!) + + elsif Is_Empty_Elmt_List (Call_List) then + return; + end if; + + -- Here is the case where we detect recursion at compile time + + -- Push our current scope for analyzing the declarations and + -- code that we will insert for the checking. + + New_Scope (Spec); + + -- This loop builds temporary variables for each of the + -- referenced globals, so that at the end of the loop the + -- list Shad_List contains these temporaries in one-to-one + -- correspondence with the elements in Var_List. + + Last := Empty; + Elm := First_Elmt (Var_List); + while Present (Elm) loop + Var := Node (Elm); + Ent := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('S')); + Append_Elmt (Ent, Shad_List); + + -- Insert a declaration for this temporary at the start of + -- the declarations for the procedure. The temporaries are + -- declared as constant objects initialized to the current + -- values of the corresponding temporaries. + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Ent, + Object_Definition => New_Occurrence_Of (Etype (Var), Loc), + Constant_Present => True, + Expression => New_Occurrence_Of (Var, Loc)); + + if No (Last) then + Prepend (Decl, Declarations (N)); + else + Insert_After (Last, Decl); + end if; + + Last := Decl; + Analyze (Decl); + Next_Elmt (Elm); + end loop; + + -- Loop through calls + + Call := First_Elmt (Call_List); + while Present (Call) loop + + -- Build a predicate expression of the form + + -- True + -- and then global1 = temp1 + -- and then global2 = temp2 + -- ... + + -- This predicate determines if any of the global values + -- referenced by the procedure have changed since the + -- current call, if not an infinite recursion is assured. + + Test := New_Occurrence_Of (Standard_True, Loc); + + Elm1 := First_Elmt (Var_List); + Elm2 := First_Elmt (Shad_List); + while Present (Elm1) loop + Test := + Make_And_Then (Loc, + Left_Opnd => Test, + Right_Opnd => + Make_Op_Eq (Loc, + Left_Opnd => New_Occurrence_Of (Node (Elm1), Loc), + Right_Opnd => New_Occurrence_Of (Node (Elm2), Loc))); + + Next_Elmt (Elm1); + Next_Elmt (Elm2); + end loop; + + -- Now we replace the call with the sequence + + -- if no-changes (see above) then + -- raise Storage_Error; + -- else + -- original-call + -- end if; + + Rewrite (Node (Call), + Make_If_Statement (Loc, + Condition => Test, + Then_Statements => New_List ( + Make_Raise_Storage_Error (Loc)), + + Else_Statements => New_List ( + Relocate_Node (Node (Call))))); + + Analyze (Node (Call)); + + Next_Elmt (Call); + end loop; + + -- Remove temporary scope stack entry used for analysis + + Pop_Scope; + end Detect_Infinite_Recursion; + + -------------------- + -- Expand_Actuals -- + -------------------- + + procedure Expand_Actuals (N : Node_Id; Subp : Entity_Id) is + Loc : constant Source_Ptr := Sloc (N); + Actual : Node_Id; + Formal : Entity_Id; + N_Node : Node_Id; + Post_Call : List_Id; + E_Formal : Entity_Id; + + procedure Add_Call_By_Copy_Code; + -- For In and In-Out parameters, where the parameter must be passed + -- by copy, this routine generates a temporary variable into which + -- the actual is copied, and then passes this as the parameter. This + -- routine also takes care of any constraint checks required for the + -- type conversion case (on both the way in and the way out). + + procedure Add_Packed_Call_By_Copy_Code; + -- This is used when the actual involves a reference to an element + -- of a packed array, where we can appropriately use a simpler + -- approach than the full call by copy code. We just copy the value + -- in and out of an apropriate temporary. + + procedure Check_Fortran_Logical; + -- A value of type Logical that is passed through a formal parameter + -- must be normalized because .TRUE. usually does not have the same + -- representation as True. We assume that .FALSE. = False = 0. + -- What about functions that return a logical type ??? + + function Make_Var (Actual : Node_Id) return Entity_Id; + -- Returns an entity that refers to the given actual parameter, + -- Actual (not including any type conversion). If Actual is an + -- entity name, then this entity is returned unchanged, otherwise + -- a renaming is created to provide an entity for the actual. + + procedure Reset_Packed_Prefix; + -- The expansion of a packed array component reference is delayed in + -- the context of a call. Now we need to complete the expansion, so we + -- unmark the analyzed bits in all prefixes. + + --------------------------- + -- Add_Call_By_Copy_Code -- + --------------------------- + + procedure Add_Call_By_Copy_Code is + Expr : Node_Id; + Init : Node_Id; + Temp : Entity_Id; + Var : Entity_Id; + V_Typ : Entity_Id; + Crep : Boolean; + + begin + Temp := Make_Defining_Identifier (Loc, New_Internal_Name ('T')); + + if Nkind (Actual) = N_Type_Conversion then + V_Typ := Etype (Expression (Actual)); + Var := Make_Var (Expression (Actual)); + Crep := not Same_Representation + (Etype (Formal), Etype (Expression (Actual))); + else + V_Typ := Etype (Actual); + Var := Make_Var (Actual); + Crep := False; + end if; + + -- Setup initialization for case of in out parameter, or an out + -- parameter where the formal is an unconstrained array (in the + -- latter case, we have to pass in an object with bounds). + + if Ekind (Formal) = E_In_Out_Parameter + or else (Is_Array_Type (Etype (Formal)) + and then + not Is_Constrained (Etype (Formal))) + then + if Nkind (Actual) = N_Type_Conversion then + if Conversion_OK (Actual) then + Init := OK_Convert_To + (Etype (Formal), New_Occurrence_Of (Var, Loc)); + else + Init := Convert_To + (Etype (Formal), New_Occurrence_Of (Var, Loc)); + end if; + else + Init := New_Occurrence_Of (Var, Loc); + end if; + + -- An initialization is created for packed conversions as + -- actuals for out parameters to enable Make_Object_Declaration + -- to determine the proper subtype for N_Node. Note that this + -- is wasteful because the extra copying on the call side is + -- not required for such out parameters. ??? + + elsif Ekind (Formal) = E_Out_Parameter + and then Nkind (Actual) = N_Type_Conversion + and then (Is_Bit_Packed_Array (Etype (Formal)) + or else + Is_Bit_Packed_Array (Etype (Expression (Actual)))) + then + if Conversion_OK (Actual) then + Init := + OK_Convert_To (Etype (Formal), New_Occurrence_Of (Var, Loc)); + else + Init := + Convert_To (Etype (Formal), New_Occurrence_Of (Var, Loc)); + end if; + else + Init := Empty; + end if; + + N_Node := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => + New_Occurrence_Of (Etype (Formal), Loc), + Expression => Init); + Set_Assignment_OK (N_Node); + Insert_Action (N, N_Node); + + -- Now, normally the deal here is that we use the defining + -- identifier created by that object declaration. There is + -- one exception to this. In the change of representation case + -- the above declaration will end up looking like: + + -- temp : type := identifier; + + -- And in this case we might as well use the identifier directly + -- and eliminate the temporary. Note that the analysis of the + -- declaration was not a waste of time in that case, since it is + -- what generated the necessary change of representation code. If + -- the change of representation introduced additional code, as in + -- a fixed-integer conversion, the expression is not an identifier + -- and must be kept. + + if Crep + and then Present (Expression (N_Node)) + and then Is_Entity_Name (Expression (N_Node)) + then + Temp := Entity (Expression (N_Node)); + Rewrite (N_Node, Make_Null_Statement (Loc)); + end if; + + -- If type conversion, use reverse conversion on exit + + if Nkind (Actual) = N_Type_Conversion then + if Conversion_OK (Actual) then + Expr := OK_Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc)); + else + Expr := Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc)); + end if; + else + Expr := New_Occurrence_Of (Temp, Loc); + end if; + + Rewrite (Actual, New_Reference_To (Temp, Loc)); + Analyze (Actual); + + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Var, Loc), + Expression => Expr)); + + Set_Assignment_OK (Name (Last (Post_Call))); + end Add_Call_By_Copy_Code; + + ---------------------------------- + -- Add_Packed_Call_By_Copy_Code -- + ---------------------------------- + + procedure Add_Packed_Call_By_Copy_Code is + Temp : Entity_Id; + Incod : Node_Id; + Outcod : Node_Id; + Lhs : Node_Id; + Rhs : Node_Id; + + begin + Reset_Packed_Prefix; + + -- Prepare to generate code + + Temp := Make_Defining_Identifier (Loc, New_Internal_Name ('T')); + Incod := Relocate_Node (Actual); + Outcod := New_Copy_Tree (Incod); + + -- Generate declaration of temporary variable, initializing it + -- with the input parameter unless we have an OUT variable. + + if Ekind (Formal) = E_Out_Parameter then + Incod := Empty; + end if; + + Insert_Action (N, + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => + New_Occurrence_Of (Etype (Formal), Loc), + Expression => Incod)); + + -- The actual is simply a reference to the temporary + + Rewrite (Actual, New_Occurrence_Of (Temp, Loc)); + + -- Generate copy out if OUT or IN OUT parameter + + if Ekind (Formal) /= E_In_Parameter then + Lhs := Outcod; + Rhs := New_Occurrence_Of (Temp, Loc); + + -- Deal with conversion + + if Nkind (Lhs) = N_Type_Conversion then + Lhs := Expression (Lhs); + Rhs := Convert_To (Etype (Actual), Rhs); + end if; + + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => Lhs, + Expression => Rhs)); + end if; + end Add_Packed_Call_By_Copy_Code; + + --------------------------- + -- Check_Fortran_Logical -- + --------------------------- + + procedure Check_Fortran_Logical is + Logical : Entity_Id := Etype (Formal); + Var : Entity_Id; + + -- Note: this is very incomplete, e.g. it does not handle arrays + -- of logical values. This is really not the right approach at all???) + + begin + if Convention (Subp) = Convention_Fortran + and then Root_Type (Etype (Formal)) = Standard_Boolean + and then Ekind (Formal) /= E_In_Parameter + then + Var := Make_Var (Actual); + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Var, Loc), + Expression => + Unchecked_Convert_To ( + Logical, + Make_Op_Ne (Loc, + Left_Opnd => New_Occurrence_Of (Var, Loc), + Right_Opnd => + Unchecked_Convert_To ( + Logical, + New_Occurrence_Of (Standard_False, Loc)))))); + end if; + end Check_Fortran_Logical; + + -------------- + -- Make_Var -- + -------------- + + function Make_Var (Actual : Node_Id) return Entity_Id is + Var : Entity_Id; + + begin + if Is_Entity_Name (Actual) then + return Entity (Actual); + + else + Var := Make_Defining_Identifier (Loc, New_Internal_Name ('T')); + + N_Node := + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Var, + Subtype_Mark => + New_Occurrence_Of (Etype (Actual), Loc), + Name => Relocate_Node (Actual)); + + Insert_Action (N, N_Node); + return Var; + end if; + end Make_Var; + + ------------------------- + -- Reset_Packed_Prefix -- + ------------------------- + + procedure Reset_Packed_Prefix is + Pfx : Node_Id := Actual; + + begin + loop + Set_Analyzed (Pfx, False); + exit when Nkind (Pfx) /= N_Selected_Component + and then Nkind (Pfx) /= N_Indexed_Component; + Pfx := Prefix (Pfx); + end loop; + end Reset_Packed_Prefix; + + -- Start of processing for Expand_Actuals + + begin + Formal := First_Formal (Subp); + Actual := First_Actual (N); + + Post_Call := New_List; + + while Present (Formal) loop + E_Formal := Etype (Formal); + + if Is_Scalar_Type (E_Formal) + or else Nkind (Actual) = N_Slice + then + Check_Fortran_Logical; + + -- RM 6.4.1 (11) + + elsif Ekind (Formal) /= E_Out_Parameter then + + -- The unusual case of the current instance of a protected type + -- requires special handling. This can only occur in the context + -- of a call within the body of a protected operation. + + if Is_Entity_Name (Actual) + and then Ekind (Entity (Actual)) = E_Protected_Type + and then In_Open_Scopes (Entity (Actual)) + then + if Scope (Subp) /= Entity (Actual) then + Error_Msg_N ("operation outside protected type may not " + & "call back its protected operations?", Actual); + end if; + + Rewrite (Actual, + Expand_Protected_Object_Reference (N, Entity (Actual))); + end if; + + Apply_Constraint_Check (Actual, E_Formal); + + -- Out parameter case. No constraint checks on access type + -- RM 6.4.1 (13) + + elsif Is_Access_Type (E_Formal) then + null; + + -- RM 6.4.1 (14) + + elsif Has_Discriminants (Base_Type (E_Formal)) + or else Has_Non_Null_Base_Init_Proc (E_Formal) + then + Apply_Constraint_Check (Actual, E_Formal); + + -- RM 6.4.1 (15) + + else + Apply_Constraint_Check (Actual, Base_Type (E_Formal)); + end if; + + -- Processing for IN-OUT and OUT parameters + + if Ekind (Formal) /= E_In_Parameter then + + -- For type conversions of arrays, apply length/range checks + + if Is_Array_Type (E_Formal) + and then Nkind (Actual) = N_Type_Conversion + then + if Is_Constrained (E_Formal) then + Apply_Length_Check (Expression (Actual), E_Formal); + else + Apply_Range_Check (Expression (Actual), E_Formal); + end if; + end if; + + -- If argument is a type conversion for a type that is passed + -- by copy, then we must pass the parameter by copy. + + if Nkind (Actual) = N_Type_Conversion + and then + (Is_Numeric_Type (E_Formal) + or else Is_Access_Type (E_Formal) + or else Is_Enumeration_Type (E_Formal) + or else Is_Bit_Packed_Array (Etype (Formal)) + or else Is_Bit_Packed_Array (Etype (Expression (Actual))) + + -- Also pass by copy if change of representation + + or else not Same_Representation + (Etype (Formal), + Etype (Expression (Actual)))) + then + Add_Call_By_Copy_Code; + + -- References to components of bit packed arrays are expanded + -- at this point, rather than at the point of analysis of the + -- actuals, to handle the expansion of the assignment to + -- [in] out parameters. + + elsif Is_Ref_To_Bit_Packed_Array (Actual) then + Add_Packed_Call_By_Copy_Code; + + -- References to slices of bit packed arrays are expanded + + elsif Is_Ref_To_Bit_Packed_Slice (Actual) then + Add_Call_By_Copy_Code; + + -- Deal with access types where the actual subtpe and the + -- formal subtype are not the same, requiring a check. + + -- It is neccessary to exclude tagged types because of "downward + -- conversion" errors and a strange assertion error in namet + -- from gnatf in bug 1215-001 ??? + + elsif Is_Access_Type (E_Formal) + and then not Same_Type (E_Formal, Etype (Actual)) + and then not Is_Tagged_Type (Designated_Type (E_Formal)) + then + Add_Call_By_Copy_Code; + + elsif Is_Entity_Name (Actual) + and then Is_Volatile (Entity (Actual)) + and then not Is_Scalar_Type (Etype (Entity (Actual))) + and then not Is_Volatile (E_Formal) + then + Add_Call_By_Copy_Code; + + elsif Nkind (Actual) = N_Indexed_Component + and then Is_Entity_Name (Prefix (Actual)) + and then Has_Volatile_Components (Entity (Prefix (Actual))) + then + Add_Call_By_Copy_Code; + end if; + + -- The only processing required for IN parameters is in the packed + -- array case, where we expand the indexed component (the circuit + -- in Exp_Ch4 deliberately left indexed components appearing as + -- actuals untouched, so that the special processing above for + -- the OUT and IN OUT cases could be performed. We could make the + -- test in Exp_Ch4 more complex and have it detect the parameter + -- mode, but it is easier simply to handle all cases here. + + -- Similarly, we have to expand slices of packed arrays here + + else + if Nkind (Actual) = N_Indexed_Component + and then Is_Packed (Etype (Prefix (Actual))) + then + Reset_Packed_Prefix; + Expand_Packed_Element_Reference (Actual); + + elsif Is_Ref_To_Bit_Packed_Array (Actual) then + Add_Packed_Call_By_Copy_Code; + + elsif Is_Ref_To_Bit_Packed_Slice (Actual) then + declare + Typ : constant Entity_Id := Etype (Actual); + + Ent : constant Entity_Id := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('T')); + + Decl : constant Node_Id := + Make_Object_Declaration (Loc, + Defining_Identifier => Ent, + Object_Definition => + New_Occurrence_Of (Typ, Loc)); + + begin + Set_No_Initialization (Decl); + + Insert_Actions (N, New_List ( + Decl, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Ent, Loc), + Expression => Relocate_Node (Actual)))); + + Rewrite + (Actual, New_Occurrence_Of (Ent, Loc)); + Analyze_And_Resolve (Actual, Typ); + end; + end if; + end if; + + Next_Formal (Formal); + Next_Actual (Actual); + end loop; + + -- Find right place to put post call stuff if it is present + + if not Is_Empty_List (Post_Call) then + + -- If call is not a list member, it must be the triggering + -- statement of a triggering alternative or an entry call + -- alternative, and we can add the post call stuff to the + -- corresponding statement list. + + if not Is_List_Member (N) then + declare + P : constant Node_Id := Parent (N); + + begin + pragma Assert (Nkind (P) = N_Triggering_Alternative + or else Nkind (P) = N_Entry_Call_Alternative); + + if Is_Non_Empty_List (Statements (P)) then + Insert_List_Before_And_Analyze + (First (Statements (P)), Post_Call); + else + Set_Statements (P, Post_Call); + end if; + end; + + -- Otherwise, normal case where N is in a statement sequence, + -- just put the post-call stuff after the call statement. + + else + Insert_Actions_After (N, Post_Call); + end if; + end if; + + -- The call node itself is re-analyzed in Expand_Call. + + end Expand_Actuals; + + ----------------- + -- Expand_Call -- + ----------------- + + -- This procedure handles expansion of function calls and procedure call + -- statements (i.e. it serves as the body for Expand_N_Function_Call and + -- Expand_N_Procedure_Call_Statement. Processing for calls includes: + + -- Replace call to Raise_Exception by Raise_Exception always if possible + -- Provide values of actuals for all formals in Extra_Formals list + -- Replace "call" to enumeration literal function by literal itself + -- Rewrite call to predefined operator as operator + -- Replace actuals to in-out parameters that are numeric conversions, + -- with explicit assignment to temporaries before and after the call. + -- Remove optional actuals if First_Optional_Parameter specified. + + -- Note that the list of actuals has been filled with default expressions + -- during semantic analysis of the call. Only the extra actuals required + -- for the 'Constrained attribute and for accessibility checks are added + -- at this point. + + procedure Expand_Call (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Remote : constant Boolean := Is_Remote_Call (N); + Subp : Entity_Id; + Orig_Subp : Entity_Id := Empty; + Parent_Subp : Entity_Id; + Parent_Formal : Entity_Id; + Actual : Node_Id; + Formal : Entity_Id; + Prev : Node_Id := Empty; + Prev_Orig : Node_Id; + Scop : Entity_Id; + Extra_Actuals : List_Id := No_List; + Cond : Node_Id; + + procedure Add_Actual_Parameter (Insert_Param : Node_Id); + -- Adds one entry to the end of the actual parameter list. Used for + -- default parameters and for extra actuals (for Extra_Formals). + -- The argument is an N_Parameter_Association node. + + procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id); + -- Adds an extra actual to the list of extra actuals. Expr + -- is the expression for the value of the actual, EF is the + -- entity for the extra formal. + + function Inherited_From_Formal (S : Entity_Id) return Entity_Id; + -- Within an instance, a type derived from a non-tagged formal derived + -- type inherits from the original parent, not from the actual. This is + -- tested in 4723-003. The current derivation mechanism has the derived + -- type inherit from the actual, which is only correct outside of the + -- instance. If the subprogram is inherited, we test for this particular + -- case through a convoluted tree traversal before setting the proper + -- subprogram to be called. + + -------------------------- + -- Add_Actual_Parameter -- + -------------------------- + + procedure Add_Actual_Parameter (Insert_Param : Node_Id) is + Actual_Expr : constant Node_Id := + Explicit_Actual_Parameter (Insert_Param); + + begin + -- Case of insertion is first named actual + + if No (Prev) or else + Nkind (Parent (Prev)) /= N_Parameter_Association + then + Set_Next_Named_Actual (Insert_Param, First_Named_Actual (N)); + Set_First_Named_Actual (N, Actual_Expr); + + if No (Prev) then + if not Present (Parameter_Associations (N)) then + Set_Parameter_Associations (N, New_List); + Append (Insert_Param, Parameter_Associations (N)); + end if; + else + Insert_After (Prev, Insert_Param); + end if; + + -- Case of insertion is not first named actual + + else + Set_Next_Named_Actual + (Insert_Param, Next_Named_Actual (Parent (Prev))); + Set_Next_Named_Actual (Parent (Prev), Actual_Expr); + Append (Insert_Param, Parameter_Associations (N)); + end if; + + Prev := Actual_Expr; + end Add_Actual_Parameter; + + ---------------------- + -- Add_Extra_Actual -- + ---------------------- + + procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id) is + Loc : constant Source_Ptr := Sloc (Expr); + + begin + if Extra_Actuals = No_List then + Extra_Actuals := New_List; + Set_Parent (Extra_Actuals, N); + end if; + + Append_To (Extra_Actuals, + Make_Parameter_Association (Loc, + Explicit_Actual_Parameter => Expr, + Selector_Name => + Make_Identifier (Loc, Chars (EF)))); + + Analyze_And_Resolve (Expr, Etype (EF)); + + end Add_Extra_Actual; + + --------------------------- + -- Inherited_From_Formal -- + --------------------------- + + function Inherited_From_Formal (S : Entity_Id) return Entity_Id is + Par : Entity_Id; + Gen_Par : Entity_Id; + Gen_Prim : Elist_Id; + Elmt : Elmt_Id; + Indic : Node_Id; + + begin + -- If the operation is inherited, it is attached to the corresponding + -- type derivation. If the parent in the derivation is a generic + -- actual, it is a subtype of the actual, and we have to recover the + -- original derived type declaration to find the proper parent. + + if Nkind (Parent (S)) /= N_Full_Type_Declaration + or else not Is_Derived_Type (Defining_Identifier (Parent (S))) + or else Nkind (Type_Definition (Original_Node (Parent (S)))) + /= N_Derived_Type_Definition + then + return Empty; + + else + Indic := + (Subtype_Indication + (Type_Definition (Original_Node (Parent (S))))); + + if Nkind (Indic) = N_Subtype_Indication then + Par := Entity (Subtype_Mark (Indic)); + else + Par := Entity (Indic); + end if; + end if; + + if not Is_Generic_Actual_Type (Par) + or else Is_Tagged_Type (Par) + or else Nkind (Parent (Par)) /= N_Subtype_Declaration + or else not In_Open_Scopes (Scope (Par)) + or else not In_Instance + then + return Empty; + + else + Gen_Par := Generic_Parent_Type (Parent (Par)); + end if; + + Gen_Prim := Collect_Primitive_Operations (Gen_Par); + Elmt := First_Elmt (Gen_Prim); + + while Present (Elmt) loop + if Chars (Node (Elmt)) = Chars (S) then + declare + F1 : Entity_Id; + F2 : Entity_Id; + begin + + F1 := First_Formal (S); + F2 := First_Formal (Node (Elmt)); + + while Present (F1) + and then Present (F2) + loop + + if Etype (F1) = Etype (F2) + or else Etype (F2) = Gen_Par + then + Next_Formal (F1); + Next_Formal (F2); + else + Next_Elmt (Elmt); + exit; -- not the right subprogram + end if; + + return Node (Elmt); + end loop; + end; + + else + Next_Elmt (Elmt); + end if; + end loop; + + raise Program_Error; + end Inherited_From_Formal; + + -- Start of processing for Expand_Call + + begin + -- Call using access to subprogram with explicit dereference + + if Nkind (Name (N)) = N_Explicit_Dereference then + Subp := Etype (Name (N)); + Parent_Subp := Empty; + + -- Case of call to simple entry, where the Name is a selected component + -- whose prefix is the task, and whose selector name is the entry name + + elsif Nkind (Name (N)) = N_Selected_Component then + Subp := Entity (Selector_Name (Name (N))); + Parent_Subp := Empty; + + -- Case of call to member of entry family, where Name is an indexed + -- component, with the prefix being a selected component giving the + -- task and entry family name, and the index being the entry index. + + elsif Nkind (Name (N)) = N_Indexed_Component then + Subp := Entity (Selector_Name (Prefix (Name (N)))); + Parent_Subp := Empty; + + -- Normal case + + else + Subp := Entity (Name (N)); + Parent_Subp := Alias (Subp); + + -- Replace call to Raise_Exception by call to Raise_Exception_Always + -- if we can tell that the first parameter cannot possibly be null. + + if not Restrictions (No_Exception_Handlers) + and then Is_RTE (Subp, RE_Raise_Exception) + then + declare + FA : constant Node_Id := Original_Node (First_Actual (N)); + + begin + -- The case we catch is where the first argument is obtained + -- using the Identity attribute (which must always be non-null) + + if Nkind (FA) = N_Attribute_Reference + and then Attribute_Name (FA) = Name_Identity + then + Subp := RTE (RE_Raise_Exception_Always); + Set_Entity (Name (N), Subp); + end if; + end; + end if; + + if Ekind (Subp) = E_Entry then + Parent_Subp := Empty; + end if; + end if; + + -- First step, compute extra actuals, corresponding to any + -- Extra_Formals present. Note that we do not access Extra_Formals + -- directly, instead we simply note the presence of the extra + -- formals as we process the regular formals and collect the + -- corresponding actuals in Extra_Actuals. + + Formal := First_Formal (Subp); + Actual := First_Actual (N); + + while Present (Formal) loop + Prev := Actual; + Prev_Orig := Original_Node (Prev); + + -- Create possible extra actual for constrained case. Usually, + -- the extra actual is of the form actual'constrained, but since + -- this attribute is only available for unconstrained records, + -- TRUE is expanded if the type of the formal happens to be + -- constrained (for instance when this procedure is inherited + -- from an unconstrained record to a constrained one) or if the + -- actual has no discriminant (its type is constrained). An + -- exception to this is the case of a private type without + -- discriminants. In this case we pass FALSE because the + -- object has underlying discriminants with defaults. + + if Present (Extra_Constrained (Formal)) then + if Ekind (Etype (Prev)) in Private_Kind + and then not Has_Discriminants (Base_Type (Etype (Prev))) + then + Add_Extra_Actual ( + New_Occurrence_Of (Standard_False, Loc), + Extra_Constrained (Formal)); + + elsif Is_Constrained (Etype (Formal)) + or else not Has_Discriminants (Etype (Prev)) + then + Add_Extra_Actual ( + New_Occurrence_Of (Standard_True, Loc), + Extra_Constrained (Formal)); + + else + -- If the actual is a type conversion, then the constrained + -- test applies to the actual, not the target type. + + declare + Act_Prev : Node_Id := Prev; + + begin + -- Test for unchecked conversions as well, which can + -- occur as out parameter actuals on calls to stream + -- procedures. + + if Nkind (Act_Prev) = N_Type_Conversion + or else Nkind (Act_Prev) = N_Unchecked_Type_Conversion + then + Act_Prev := Expression (Act_Prev); + end if; + + Add_Extra_Actual ( + Make_Attribute_Reference (Sloc (Prev), + Prefix => Duplicate_Subexpr (Act_Prev, Name_Req => True), + Attribute_Name => Name_Constrained), + Extra_Constrained (Formal)); + end; + end if; + end if; + + -- Create possible extra actual for accessibility level + + if Present (Extra_Accessibility (Formal)) then + if Is_Entity_Name (Prev_Orig) then + + -- When passing an access parameter as the actual to another + -- access parameter we need to pass along the actual's own + -- associated access level parameter. This is done is we are + -- in the scope of the formal access parameter (if this is an + -- inlined body the extra formal is irrelevant). + + if Ekind (Entity (Prev_Orig)) in Formal_Kind + and then Ekind (Etype (Prev_Orig)) = E_Anonymous_Access_Type + and then In_Open_Scopes (Scope (Entity (Prev_Orig))) + then + declare + Parm_Ent : constant Entity_Id := Param_Entity (Prev_Orig); + + begin + pragma Assert (Present (Parm_Ent)); + + if Present (Extra_Accessibility (Parm_Ent)) then + Add_Extra_Actual ( + New_Occurrence_Of + (Extra_Accessibility (Parm_Ent), Loc), + Extra_Accessibility (Formal)); + + -- If the actual access parameter does not have an + -- associated extra formal providing its scope level, + -- then treat the actual as having library-level + -- accessibility. + + else + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Intval => Scope_Depth (Standard_Standard)), + Extra_Accessibility (Formal)); + end if; + end; + + -- The actual is a normal access value, so just pass the + -- level of the actual's access type. + + else + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Intval => Type_Access_Level (Etype (Prev_Orig))), + Extra_Accessibility (Formal)); + end if; + + else + case Nkind (Prev_Orig) is + + when N_Attribute_Reference => + + case Get_Attribute_Id (Attribute_Name (Prev_Orig)) is + + -- For X'Access, pass on the level of the prefix X + + when Attribute_Access => + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Intval => + Object_Access_Level (Prefix (Prev_Orig))), + Extra_Accessibility (Formal)); + + -- Treat the unchecked attributes as library-level + + when Attribute_Unchecked_Access | + Attribute_Unrestricted_Access => + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Intval => Scope_Depth (Standard_Standard)), + Extra_Accessibility (Formal)); + + -- No other cases of attributes returning access + -- values that can be passed to access parameters + + when others => + raise Program_Error; + + end case; + + -- For allocators we pass the level of the execution of + -- the called subprogram, which is one greater than the + -- current scope level. + + when N_Allocator => + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Scope_Depth (Current_Scope) + 1), + Extra_Accessibility (Formal)); + + -- For other cases we simply pass the level of the + -- actual's access type. + + when others => + Add_Extra_Actual ( + Make_Integer_Literal (Loc, + Intval => Type_Access_Level (Etype (Prev_Orig))), + Extra_Accessibility (Formal)); + + end case; + end if; + end if; + + -- Perform the check of 4.6(49) that prevents a null value + -- from being passed as an actual to an access parameter. + -- Note that the check is elided in the common cases of + -- passing an access attribute or access parameter as an + -- actual. Also, we currently don't enforce this check for + -- expander-generated actuals and when -gnatdj is set. + + if Ekind (Etype (Formal)) /= E_Anonymous_Access_Type + or else Suppress_Accessibility_Checks (Subp) + then + null; + + elsif Debug_Flag_J then + null; + + elsif not Comes_From_Source (Prev) then + null; + + elsif Is_Entity_Name (Prev) + and then Ekind (Etype (Prev)) = E_Anonymous_Access_Type + then + null; + + elsif Nkind (Prev) = N_Allocator + or else Nkind (Prev) = N_Attribute_Reference + then + null; + + -- Suppress null checks when passing to access parameters + -- of Java subprograms. (Should this be done for other + -- foreign conventions as well ???) + + elsif Convention (Subp) = Convention_Java then + null; + + else + Cond := + Make_Op_Eq (Loc, + Left_Opnd => Duplicate_Subexpr (Prev), + Right_Opnd => Make_Null (Loc)); + Insert_Action (Prev, Make_Raise_Constraint_Error (Loc, Cond)); + end if; + + -- Perform apropriate validity checks on parameters + + if Validity_Checks_On then + + if Ekind (Formal) = E_In_Parameter + and then Validity_Check_In_Params + then + Ensure_Valid (Actual); + + elsif Ekind (Formal) = E_In_Out_Parameter + and then Validity_Check_In_Out_Params + then + Ensure_Valid (Actual); + end if; + end if; + + -- For IN OUT and OUT parameters, ensure that subscripts are valid + -- since this is a left side reference. We only do this for calls + -- from the source program since we assume that compiler generated + -- calls explicitly generate any required checks. We also need it + -- only if we are doing standard validity checks, since clearly it + -- is not needed if validity checks are off, and in subscript + -- validity checking mode, all indexed components are checked with + -- a call directly from Expand_N_Indexed_Component. + + if Comes_From_Source (N) + and then Ekind (Formal) /= E_In_Parameter + and then Validity_Checks_On + and then Validity_Check_Default + and then not Validity_Check_Subscripts + then + Check_Valid_Lvalue_Subscripts (Actual); + end if; + + -- If the formal is class wide and the actual is an aggregate, force + -- evaluation so that the back end who does not know about class-wide + -- type, does not generate a temporary of the wrong size. + + if not Is_Class_Wide_Type (Etype (Formal)) then + null; + + elsif Nkind (Actual) = N_Aggregate + or else (Nkind (Actual) = N_Qualified_Expression + and then Nkind (Expression (Actual)) = N_Aggregate) + then + Force_Evaluation (Actual); + end if; + + -- In a remote call, if the formal is of a class-wide type, check + -- that the actual meets the requirements described in E.4(18). + + if Remote + and then Is_Class_Wide_Type (Etype (Formal)) + then + Insert_Action (Actual, + Make_Implicit_If_Statement (N, + Condition => + Make_Op_Not (Loc, + Get_Remotely_Callable (Duplicate_Subexpr (Actual))), + Then_Statements => New_List ( + Make_Procedure_Call_Statement (Loc, + New_Occurrence_Of (RTE + (RE_Raise_Program_Error_For_E_4_18), Loc))))); + end if; + + Next_Actual (Actual); + Next_Formal (Formal); + end loop; + + -- If we are expanding a rhs of an assignement we need to check if + -- tag propagation is needed. This code belongs theorically in Analyze + -- Assignment but has to be done earlier (bottom-up) because the + -- assignment might be transformed into a declaration for an uncons- + -- trained value, if the expression is classwide. + + if Nkind (N) = N_Function_Call + and then Is_Tag_Indeterminate (N) + and then Is_Entity_Name (Name (N)) + then + declare + Ass : Node_Id := Empty; + + begin + if Nkind (Parent (N)) = N_Assignment_Statement then + Ass := Parent (N); + + elsif Nkind (Parent (N)) = N_Qualified_Expression + and then Nkind (Parent (Parent (N))) = N_Assignment_Statement + then + Ass := Parent (Parent (N)); + end if; + + if Present (Ass) + and then Is_Class_Wide_Type (Etype (Name (Ass))) + then + Propagate_Tag (Name (Ass), N); + return; + end if; + end; + end if; + + -- Deals with Dispatch_Call if we still have a call, before expanding + -- extra actuals since this will be done on the re-analysis of the + -- dispatching call. Note that we do not try to shorten the actual + -- list for a dispatching call, it would not make sense to do so. + -- Expansion of dispatching calls is suppressed when Java_VM, because + -- the JVM back end directly handles the generation of dispatching + -- calls and would have to undo any expansion to an indirect call. + + if (Nkind (N) = N_Function_Call + or else Nkind (N) = N_Procedure_Call_Statement) + and then Present (Controlling_Argument (N)) + and then not Java_VM + then + Expand_Dispatch_Call (N); + return; + + -- Similarly, expand calls to RCI subprograms on which pragma + -- All_Calls_Remote applies. The rewriting will be reanalyzed + -- later. Do this only when the call comes from source since we do + -- not want such a rewritting to occur in expanded code. + + elsif Is_All_Remote_Call (N) then + Expand_All_Calls_Remote_Subprogram_Call (N); + + -- Similarly, do not add extra actuals for an entry call whose entity + -- is a protected procedure, or for an internal protected subprogram + -- call, because it will be rewritten as a protected subprogram call + -- and reanalyzed (see Expand_Protected_Subprogram_Call). + + elsif Is_Protected_Type (Scope (Subp)) + and then (Ekind (Subp) = E_Procedure + or else Ekind (Subp) = E_Function) + then + null; + + -- During that loop we gathered the extra actuals (the ones that + -- correspond to Extra_Formals), so now they can be appended. + + else + while Is_Non_Empty_List (Extra_Actuals) loop + Add_Actual_Parameter (Remove_Head (Extra_Actuals)); + end loop; + end if; + + if Ekind (Subp) = E_Procedure + or else (Ekind (Subp) = E_Subprogram_Type + and then Etype (Subp) = Standard_Void_Type) + or else Is_Entry (Subp) + then + Expand_Actuals (N, Subp); + end if; + + -- If the subprogram is a renaming, or if it is inherited, replace it + -- in the call with the name of the actual subprogram being called. + -- If this is a dispatching call, the run-time decides what to call. + -- The Alias attribute does not apply to entries. + + if Nkind (N) /= N_Entry_Call_Statement + and then No (Controlling_Argument (N)) + and then Present (Parent_Subp) + then + if Present (Inherited_From_Formal (Subp)) then + Parent_Subp := Inherited_From_Formal (Subp); + else + while Present (Alias (Parent_Subp)) loop + Parent_Subp := Alias (Parent_Subp); + end loop; + end if; + + Set_Entity (Name (N), Parent_Subp); + + if Is_Abstract (Parent_Subp) + and then not In_Instance + then + Error_Msg_NE + ("cannot call abstract subprogram &!", Name (N), Parent_Subp); + end if; + + -- Add an explicit conversion for parameter of the derived type. + -- This is only done for scalar and access in-parameters. Others + -- have been expanded in expand_actuals. + + Formal := First_Formal (Subp); + Parent_Formal := First_Formal (Parent_Subp); + Actual := First_Actual (N); + + -- It is not clear that conversion is needed for intrinsic + -- subprograms, but it certainly is for those that are user- + -- defined, and that can be inherited on derivation, namely + -- unchecked conversion and deallocation. + -- General case needs study ??? + + if not Is_Intrinsic_Subprogram (Parent_Subp) + or else Is_Generic_Instance (Parent_Subp) + then + while Present (Formal) loop + + if Etype (Formal) /= Etype (Parent_Formal) + and then Is_Scalar_Type (Etype (Formal)) + and then Ekind (Formal) = E_In_Parameter + then + Rewrite (Actual, + OK_Convert_To (Etype (Parent_Formal), + Relocate_Node (Actual))); + + Analyze (Actual); + Resolve (Actual, Etype (Parent_Formal)); + Enable_Range_Check (Actual); + + elsif Is_Access_Type (Etype (Formal)) + and then Base_Type (Etype (Parent_Formal)) + /= Base_Type (Etype (Actual)) + then + if Ekind (Formal) /= E_In_Parameter then + Rewrite (Actual, + Convert_To (Etype (Parent_Formal), + Relocate_Node (Actual))); + + Analyze (Actual); + Resolve (Actual, Etype (Parent_Formal)); + + elsif + Ekind (Etype (Parent_Formal)) = E_Anonymous_Access_Type + and then + Designated_Type (Etype (Parent_Formal)) + /= Designated_Type (Etype (Actual)) + and then not Is_Controlling_Formal (Formal) + then + + -- This unchecked conversion is not necessary unless + -- inlining is unabled, because in that case the type + -- mismatch may become visible in the body about to be + -- inlined. + + Rewrite (Actual, + Unchecked_Convert_To (Etype (Parent_Formal), + Relocate_Node (Actual))); + + Analyze (Actual); + Resolve (Actual, Etype (Parent_Formal)); + end if; + end if; + + Next_Formal (Formal); + Next_Formal (Parent_Formal); + Next_Actual (Actual); + end loop; + end if; + + Orig_Subp := Subp; + Subp := Parent_Subp; + end if; + + -- Some more special cases for cases other than explicit dereference + + if Nkind (Name (N)) /= N_Explicit_Dereference then + + -- Calls to an enumeration literal are replaced by the literal + -- This case occurs only when we have a call to a function that + -- is a renaming of an enumeration literal. The normal case of + -- a direct reference to an enumeration literal has already been + -- been dealt with by Resolve_Call. If the function is itself + -- inherited (see 7423-001) the literal of the parent type must + -- be explicitly converted to the return type of the function. + + if Ekind (Subp) = E_Enumeration_Literal then + if Base_Type (Etype (Subp)) /= Base_Type (Etype (N)) then + Rewrite + (N, Convert_To (Etype (N), New_Occurrence_Of (Subp, Loc))); + else + Rewrite (N, New_Occurrence_Of (Subp, Loc)); + Resolve (N, Etype (N)); + end if; + end if; + + -- Handle case of access to protected subprogram type + + else + if Ekind (Base_Type (Etype (Prefix (Name (N))))) = + E_Access_Protected_Subprogram_Type + then + -- If this is a call through an access to protected operation, + -- the prefix has the form (object'address, operation'access). + -- Rewrite as a for other protected calls: the object is the + -- first parameter of the list of actuals. + + declare + Call : Node_Id; + Parm : List_Id; + Nam : Node_Id; + Obj : Node_Id; + Ptr : Node_Id := Prefix (Name (N)); + T : Entity_Id := Equivalent_Type (Base_Type (Etype (Ptr))); + D_T : Entity_Id := Designated_Type (Base_Type (Etype (Ptr))); + + begin + Obj := Make_Selected_Component (Loc, + Prefix => Unchecked_Convert_To (T, Ptr), + Selector_Name => New_Occurrence_Of (First_Entity (T), Loc)); + + Nam := Make_Selected_Component (Loc, + Prefix => Unchecked_Convert_To (T, Ptr), + Selector_Name => New_Occurrence_Of ( + Next_Entity (First_Entity (T)), Loc)); + + Nam := Make_Explicit_Dereference (Loc, Nam); + + if Present (Parameter_Associations (N)) then + Parm := Parameter_Associations (N); + else + Parm := New_List; + end if; + + Prepend (Obj, Parm); + + if Etype (D_T) = Standard_Void_Type then + Call := Make_Procedure_Call_Statement (Loc, + Name => Nam, + Parameter_Associations => Parm); + else + Call := Make_Function_Call (Loc, + Name => Nam, + Parameter_Associations => Parm); + end if; + + Set_First_Named_Actual (Call, First_Named_Actual (N)); + + Set_Etype (Call, Etype (D_T)); + + -- We do not re-analyze the call to avoid infinite recursion. + -- We analyze separately the prefix and the object, and set + -- the checks on the prefix that would otherwise be emitted + -- when resolving a call. + + Rewrite (N, Call); + Analyze (Nam); + Apply_Access_Check (Nam); + Analyze (Obj); + return; + end; + end if; + end if; + + -- If this is a call to an intrinsic subprogram, then perform the + -- appropriate expansion to the corresponding tree node and we + -- are all done (since after that the call is gone!) + + if Is_Intrinsic_Subprogram (Subp) then + Expand_Intrinsic_Call (N, Subp); + return; + end if; + + if Ekind (Subp) = E_Function + or else Ekind (Subp) = E_Procedure + then + if Is_Inlined (Subp) then + + declare + Spec : constant Node_Id := Unit_Declaration_Node (Subp); + + begin + -- Verify that the body to inline has already been seen, + -- and that if the body is in the current unit the inlining + -- does not occur earlier. This avoids order-of-elaboration + -- problems in gigi. + + if Present (Spec) + and then Nkind (Spec) = N_Subprogram_Declaration + and then Present (Body_To_Inline (Spec)) + and then (In_Extended_Main_Code_Unit (N) + or else In_Extended_Main_Code_Unit (Parent (N))) + and then (not In_Same_Extended_Unit + (Sloc (Body_To_Inline (Spec)), Loc) + or else + Earlier_In_Extended_Unit + (Sloc (Body_To_Inline (Spec)), Loc)) + then + Expand_Inlined_Call (N, Subp, Orig_Subp); + + else + -- Let the back-end handle it. + + Add_Inlined_Body (Subp); + + if Front_End_Inlining + and then Nkind (Spec) = N_Subprogram_Declaration + and then (In_Extended_Main_Code_Unit (N)) + and then No (Body_To_Inline (Spec)) + and then not Has_Completion (Subp) + and then In_Same_Extended_Unit (Sloc (Spec), Loc) + and then Ineffective_Inline_Warnings + then + Error_Msg_N + ("call cannot be inlined before body is seen?", N); + end if; + end if; + end; + end if; + end if; + + -- Check for a protected subprogram. This is either an intra-object + -- call, or a protected function call. Protected procedure calls are + -- rewritten as entry calls and handled accordingly. + + Scop := Scope (Subp); + + if Nkind (N) /= N_Entry_Call_Statement + and then Is_Protected_Type (Scop) + then + -- If the call is an internal one, it is rewritten as a call to + -- to the corresponding unprotected subprogram. + + Expand_Protected_Subprogram_Call (N, Subp, Scop); + end if; + + -- Functions returning controlled objects need special attention + + if Controlled_Type (Etype (Subp)) + and then not Is_Return_By_Reference_Type (Etype (Subp)) + then + Expand_Ctrl_Function_Call (N); + end if; + + -- Test for First_Optional_Parameter, and if so, truncate parameter + -- list if there are optional parameters at the trailing end. + -- Note we never delete procedures for call via a pointer. + + if (Ekind (Subp) = E_Procedure or else Ekind (Subp) = E_Function) + and then Present (First_Optional_Parameter (Subp)) + then + declare + Last_Keep_Arg : Node_Id; + + begin + -- Last_Keep_Arg will hold the last actual that should be + -- retained. If it remains empty at the end, it means that + -- all parameters are optional. + + Last_Keep_Arg := Empty; + + -- Find first optional parameter, must be present since we + -- checked the validity of the parameter before setting it. + + Formal := First_Formal (Subp); + Actual := First_Actual (N); + while Formal /= First_Optional_Parameter (Subp) loop + Last_Keep_Arg := Actual; + Next_Formal (Formal); + Next_Actual (Actual); + end loop; + + -- Now we have Formal and Actual pointing to the first + -- potentially droppable argument. We can drop all the + -- trailing arguments whose actual matches the default. + -- Note that we know that all remaining formals have + -- defaults, because we checked that this requirement + -- was met before setting First_Optional_Parameter. + + -- We use Fully_Conformant_Expressions to check for identity + -- between formals and actuals, which may miss some cases, but + -- on the other hand, this is only an optimization (if we fail + -- to truncate a parameter it does not affect functionality). + -- So if the default is 3 and the actual is 1+2, we consider + -- them unequal, which hardly seems worrisome. + + while Present (Formal) loop + if not Fully_Conformant_Expressions + (Actual, Default_Value (Formal)) + then + Last_Keep_Arg := Actual; + end if; + + Next_Formal (Formal); + Next_Actual (Actual); + end loop; + + -- If no arguments, delete entire list, this is the easy case + + if No (Last_Keep_Arg) then + while Is_Non_Empty_List (Parameter_Associations (N)) loop + Delete_Tree (Remove_Head (Parameter_Associations (N))); + end loop; + + Set_Parameter_Associations (N, No_List); + Set_First_Named_Actual (N, Empty); + + -- Case where at the last retained argument is positional. This + -- is also an easy case, since the retained arguments are already + -- in the right form, and we don't need to worry about the order + -- of arguments that get eliminated. + + elsif Is_List_Member (Last_Keep_Arg) then + while Present (Next (Last_Keep_Arg)) loop + Delete_Tree (Remove_Next (Last_Keep_Arg)); + end loop; + + Set_First_Named_Actual (N, Empty); + + -- This is the annoying case where the last retained argument + -- is a named parameter. Since the original arguments are not + -- in declaration order, we may have to delete some fairly + -- random collection of arguments. + + else + declare + Temp : Node_Id; + Passoc : Node_Id; + Junk : Node_Id; + + begin + -- First step, remove all the named parameters from the + -- list (they are still chained using First_Named_Actual + -- and Next_Named_Actual, so we have not lost them!) + + Temp := First (Parameter_Associations (N)); + + -- Case of all parameters named, remove them all + + if Nkind (Temp) = N_Parameter_Association then + while Is_Non_Empty_List (Parameter_Associations (N)) loop + Temp := Remove_Head (Parameter_Associations (N)); + end loop; + + -- Case of mixed positional/named, remove named parameters + + else + while Nkind (Next (Temp)) /= N_Parameter_Association loop + Next (Temp); + end loop; + + while Present (Next (Temp)) loop + Junk := Remove_Next (Temp); + end loop; + end if; + + -- Now we loop through the named parameters, till we get + -- to the last one to be retained, adding them to the list. + -- Note that the Next_Named_Actual list does not need to be + -- touched since we are only reordering them on the actual + -- parameter association list. + + Passoc := Parent (First_Named_Actual (N)); + loop + Temp := Relocate_Node (Passoc); + Append_To + (Parameter_Associations (N), Temp); + exit when + Last_Keep_Arg = Explicit_Actual_Parameter (Passoc); + Passoc := Parent (Next_Named_Actual (Passoc)); + end loop; + + Set_Next_Named_Actual (Temp, Empty); + + loop + Temp := Next_Named_Actual (Passoc); + exit when No (Temp); + Set_Next_Named_Actual + (Passoc, Next_Named_Actual (Parent (Temp))); + Delete_Tree (Temp); + end loop; + end; + end if; + end; + end if; + + end Expand_Call; + + -------------------------- + -- Expand_Inlined_Call -- + -------------------------- + + procedure Expand_Inlined_Call + (N : Node_Id; + Subp : Entity_Id; + Orig_Subp : Entity_Id) + is + Loc : constant Source_Ptr := Sloc (N); + Blk : Node_Id; + Bod : Node_Id; + Decl : Node_Id; + Exit_Lab : Entity_Id := Empty; + F : Entity_Id; + A : Node_Id; + Lab_Decl : Node_Id; + Lab_Id : Node_Id; + New_A : Node_Id; + Num_Ret : Int := 0; + Orig_Bod : constant Node_Id := + Body_To_Inline (Unit_Declaration_Node (Subp)); + Ret_Type : Entity_Id; + Targ : Node_Id; + Temp : Entity_Id; + Temp_Typ : Entity_Id; + + procedure Make_Exit_Label; + -- Build declaration for exit label to be used in Return statements. + + function Process_Formals (N : Node_Id) return Traverse_Result; + -- Replace occurrence of a formal with the corresponding actual, or + -- the thunk generated for it. + + procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id); + -- If the function body is a single expression, replace call with + -- expression, else insert block appropriately. + + procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id); + -- If procedure body has no local variables, inline body without + -- creating block, otherwise rewrite call with block. + + --------------------- + -- Make_Exit_Label -- + --------------------- + + procedure Make_Exit_Label is + begin + -- Create exit label for subprogram, if one doesn't exist yet. + + if No (Exit_Lab) then + Lab_Id := Make_Identifier (Loc, New_Internal_Name ('L')); + Set_Entity (Lab_Id, + Make_Defining_Identifier (Loc, Chars (Lab_Id))); + Exit_Lab := Make_Label (Loc, Lab_Id); + + Lab_Decl := + Make_Implicit_Label_Declaration (Loc, + Defining_Identifier => Entity (Lab_Id), + Label_Construct => Exit_Lab); + end if; + end Make_Exit_Label; + + --------------------- + -- Process_Formals -- + --------------------- + + function Process_Formals (N : Node_Id) return Traverse_Result is + A : Entity_Id; + E : Entity_Id; + Ret : Node_Id; + + begin + if Is_Entity_Name (N) + and then Present (Entity (N)) + then + E := Entity (N); + + if Is_Formal (E) + and then Scope (E) = Subp + then + A := Renamed_Object (E); + + if Is_Entity_Name (A) then + Rewrite (N, New_Occurrence_Of (Entity (A), Loc)); + + elsif Nkind (A) = N_Defining_Identifier then + Rewrite (N, New_Occurrence_Of (A, Loc)); + + else -- numeric literal + Rewrite (N, New_Copy (A)); + end if; + end if; + + return Skip; + + elsif Nkind (N) = N_Return_Statement then + + if No (Expression (N)) then + Make_Exit_Label; + Rewrite (N, Make_Goto_Statement (Loc, + Name => New_Copy (Lab_Id))); + + else + if Nkind (Parent (N)) = N_Handled_Sequence_Of_Statements + and then Nkind (Parent (Parent (N))) = N_Subprogram_Body + then + -- function body is a single expression. No need for + -- exit label. + null; + + else + Num_Ret := Num_Ret + 1; + Make_Exit_Label; + end if; + + -- Because of the presence of private types, the views of the + -- expression and the context may be different, so place an + -- unchecked conversion to the context type to avoid spurious + -- errors, eg. when the expression is a numeric literal and + -- the context is private. If the expression is an aggregate, + -- use a qualified expression, because an aggregate is not a + -- legal argument of a conversion. + + if Nkind (Expression (N)) = N_Aggregate then + Ret := + Make_Qualified_Expression (Sloc (N), + Subtype_Mark => New_Occurrence_Of (Ret_Type, Sloc (N)), + Expression => Relocate_Node (Expression (N))); + else + Ret := + Unchecked_Convert_To + (Ret_Type, Relocate_Node (Expression (N))); + end if; + + if Nkind (Targ) = N_Defining_Identifier then + Rewrite (N, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Targ, Loc), + Expression => Ret)); + else + Rewrite (N, + Make_Assignment_Statement (Loc, + Name => New_Copy (Targ), + Expression => Ret)); + end if; + + Set_Assignment_OK (Name (N)); + + if Present (Exit_Lab) then + Insert_After (N, + Make_Goto_Statement (Loc, + Name => New_Copy (Lab_Id))); + end if; + end if; + + return OK; + + else + return OK; + end if; + end Process_Formals; + + procedure Replace_Formals is new Traverse_Proc (Process_Formals); + + --------------------------- + -- Rewrite_Function_Call -- + --------------------------- + + procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id) is + HSS : Node_Id := Handled_Statement_Sequence (Blk); + Fst : Node_Id := First (Statements (HSS)); + + begin + + -- Optimize simple case: function body is a single return statement, + -- which has been expanded into an assignment. + + if Is_Empty_List (Declarations (Blk)) + and then Nkind (Fst) = N_Assignment_Statement + and then No (Next (Fst)) + then + + -- The function call may have been rewritten as the temporary + -- that holds the result of the call, in which case remove the + -- now useless declaration. + + if Nkind (N) = N_Identifier + and then Nkind (Parent (Entity (N))) = N_Object_Declaration + then + Rewrite (Parent (Entity (N)), Make_Null_Statement (Loc)); + end if; + + Rewrite (N, Expression (Fst)); + + elsif Nkind (N) = N_Identifier + and then Nkind (Parent (Entity (N))) = N_Object_Declaration + then + + -- The block assigns the result of the call to the temporary. + + Insert_After (Parent (Entity (N)), Blk); + + elsif Nkind (Parent (N)) = N_Assignment_Statement + and then Is_Entity_Name (Name (Parent (N))) + then + + -- replace assignment with the block. + + Rewrite (Parent (N), Blk); + + elsif Nkind (Parent (N)) = N_Object_Declaration then + Set_Expression (Parent (N), Empty); + Insert_After (Parent (N), Blk); + end if; + end Rewrite_Function_Call; + + ---------------------------- + -- Rewrite_Procedure_Call -- + ---------------------------- + + procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id) is + HSS : Node_Id := Handled_Statement_Sequence (Blk); + + begin + if Is_Empty_List (Declarations (Blk)) then + Insert_List_After (N, Statements (HSS)); + Rewrite (N, Make_Null_Statement (Loc)); + else + Rewrite (N, Blk); + end if; + end Rewrite_Procedure_Call; + + -- Start of processing for Expand_Inlined_Call + + begin + if Nkind (Orig_Bod) = N_Defining_Identifier then + + -- Subprogram is a renaming_as_body. Calls appearing after the + -- renaming can be replaced with calls to the renamed entity + -- directly, because the subprograms are subtype conformant. + + Set_Name (N, New_Occurrence_Of (Orig_Bod, Loc)); + return; + end if; + + -- Use generic machinery to copy body of inlined subprogram, as if it + -- were an instantiation, resetting source locations appropriately, so + -- that nested inlined calls appear in the main unit. + + Save_Env (Subp, Empty); + Set_Copied_Sloc (N, Defining_Entity (Orig_Bod)); + + Bod := + Copy_Generic_Node (Orig_Bod, Empty, Instantiating => True); + + Blk := + Make_Block_Statement (Loc, + Declarations => Declarations (Bod), + Handled_Statement_Sequence => Handled_Statement_Sequence (Bod)); + + if No (Declarations (Bod)) then + Set_Declarations (Blk, New_List); + end if; + + -- If this is a derived function, establish the proper return type. + + if Present (Orig_Subp) + and then Orig_Subp /= Subp + then + Ret_Type := Etype (Orig_Subp); + else + Ret_Type := Etype (Subp); + end if; + + F := First_Formal (Subp); + A := First_Actual (N); + + -- Create temporaries for the actuals that are expressions, or that + -- are scalars and require copying to preserve semantics. + + while Present (F) loop + + if Present (Renamed_Object (F)) then + Error_Msg_N (" cannot inline call to recursive subprogram", N); + return; + end if; + + -- If the argument may be a controlling argument in a call within + -- the inlined body, we must preserve its classwide nature to + -- insure that dynamic dispatching take place subsequently. + -- If the formal has a constraint it must be preserved to retain + -- the semantics of the body. + + if Is_Class_Wide_Type (Etype (F)) + or else (Is_Access_Type (Etype (F)) + and then + Is_Class_Wide_Type (Designated_Type (Etype (F)))) + then + Temp_Typ := Etype (F); + + elsif Base_Type (Etype (F)) = Base_Type (Etype (A)) + and then Etype (F) /= Base_Type (Etype (F)) + then + Temp_Typ := Etype (F); + + else + Temp_Typ := Etype (A); + end if; + + if (not Is_Entity_Name (A) + and then Nkind (A) /= N_Integer_Literal + and then Nkind (A) /= N_Real_Literal) + + or else Is_Scalar_Type (Etype (A)) + then + Temp := + Make_Defining_Identifier (Loc, + Chars => New_Internal_Name ('C')); + + -- If the actual for an in/in-out parameter is a view conversion, + -- make it into an unchecked conversion, given that an untagged + -- type conversion is not a proper object for a renaming. + -- In-out conversions that involve real conversions have already + -- been transformed in Expand_Actuals. + + if Nkind (A) = N_Type_Conversion + and then + (Ekind (F) = E_In_Out_Parameter + or else not Is_Tagged_Type (Etype (F))) + then + New_A := Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Etype (F), Loc), + Expression => Relocate_Node (Expression (A))); + + elsif Etype (F) /= Etype (A) then + New_A := Unchecked_Convert_To (Etype (F), Relocate_Node (A)); + Temp_Typ := Etype (F); + + else + New_A := Relocate_Node (A); + end if; + + Set_Sloc (New_A, Sloc (N)); + + if Ekind (F) = E_In_Parameter + and then not Is_Limited_Type (Etype (A)) + then + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Temp_Typ, Loc), + Expression => New_A); + else + Decl := + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Temp, + Subtype_Mark => New_Occurrence_Of (Temp_Typ, Loc), + Name => New_A); + end if; + + Prepend (Decl, Declarations (Blk)); + Set_Renamed_Object (F, Temp); + + else + if Etype (F) /= Etype (A) then + Set_Renamed_Object + (F, Unchecked_Convert_To (Etype (F), Relocate_Node (A))); + else + Set_Renamed_Object (F, A); + end if; + end if; + + Next_Formal (F); + Next_Actual (A); + end loop; + + -- Establish target of function call. If context is not assignment or + -- declaration, create a temporary as a target. The declaration for + -- the temporary may be subsequently optimized away if the body is a + -- single expression, or if the left-hand side of the assignment is + -- simple enough. + + if Ekind (Subp) = E_Function then + if Nkind (Parent (N)) = N_Assignment_Statement + and then Is_Entity_Name (Name (Parent (N))) + then + Targ := Name (Parent (N)); + + else + -- Replace call with temporary, and create its declaration. + + Temp := + Make_Defining_Identifier (Loc, New_Internal_Name ('C')); + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => + New_Occurrence_Of (Ret_Type, Loc)); + + Set_No_Initialization (Decl); + Insert_Action (N, Decl); + Rewrite (N, New_Occurrence_Of (Temp, Loc)); + Targ := Temp; + end if; + end if; + + -- Traverse the tree and replace formals with actuals or their thunks. + -- Attach block to tree before analysis and rewriting. + + Replace_Formals (Blk); + Set_Parent (Blk, N); + + if Present (Exit_Lab) then + + -- If the body was a single expression, the single return statement + -- and the corresponding label are useless. + + if Num_Ret = 1 + and then + Nkind (Last (Statements (Handled_Statement_Sequence (Blk)))) = + N_Goto_Statement + then + Remove (Last (Statements (Handled_Statement_Sequence (Blk)))); + else + Append (Lab_Decl, (Declarations (Blk))); + Append (Exit_Lab, Statements (Handled_Statement_Sequence (Blk))); + end if; + end if; + + -- Analyze Blk with In_Inlined_Body set, to avoid spurious errors on + -- conflicting private views that Gigi would ignore. + + declare + I_Flag : constant Boolean := In_Inlined_Body; + + begin + In_Inlined_Body := True; + Analyze (Blk); + In_Inlined_Body := I_Flag; + end; + + if Ekind (Subp) = E_Procedure then + Rewrite_Procedure_Call (N, Blk); + else + Rewrite_Function_Call (N, Blk); + end if; + + Restore_Env; + + -- Cleanup mapping between formals and actuals, for other expansions. + + F := First_Formal (Subp); + + while Present (F) loop + Set_Renamed_Object (F, Empty); + Next_Formal (F); + end loop; + end Expand_Inlined_Call; + + ---------------------------- + -- Expand_N_Function_Call -- + ---------------------------- + + procedure Expand_N_Function_Call (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + + function Returned_By_Reference return Boolean; + -- If the return type is returned through the secondary stack. i.e. + -- by reference, we don't want to create a temporary to force stack + -- checking. + + function Returned_By_Reference return Boolean is + S : Entity_Id := Current_Scope; + + begin + if Is_Return_By_Reference_Type (Typ) then + return True; + + elsif Nkind (Parent (N)) /= N_Return_Statement then + return False; + + elsif Requires_Transient_Scope (Typ) then + + -- Verify that the return type of the enclosing function has + -- the same constrained status as that of the expression. + + while Ekind (S) /= E_Function loop + S := Scope (S); + end loop; + + return Is_Constrained (Typ) = Is_Constrained (Etype (S)); + else + return False; + end if; + end Returned_By_Reference; + + -- Start of processing for Expand_N_Function_Call + + begin + -- A special check. If stack checking is enabled, and the return type + -- might generate a large temporary, and the call is not the right + -- side of an assignment, then generate an explicit temporary. We do + -- this because otherwise gigi may generate a large temporary on the + -- fly and this can cause trouble with stack checking. + + if May_Generate_Large_Temp (Typ) + and then Nkind (Parent (N)) /= N_Assignment_Statement + and then + (Nkind (Parent (N)) /= N_Object_Declaration + or else Expression (Parent (N)) /= N) + and then not Returned_By_Reference + then + -- Note: it might be thought that it would be OK to use a call to + -- Force_Evaluation here, but that's not good enough, because that + -- results in a 'Reference construct that may still need a temporary. + + declare + Loc : constant Source_Ptr := Sloc (N); + Temp_Obj : constant Entity_Id := Make_Defining_Identifier (Loc, + New_Internal_Name ('F')); + Temp_Typ : Entity_Id := Typ; + Decl : Node_Id; + A : Node_Id; + F : Entity_Id; + Proc : Entity_Id; + + begin + if Is_Tagged_Type (Typ) + and then Present (Controlling_Argument (N)) + then + if Nkind (Parent (N)) /= N_Procedure_Call_Statement + and then Nkind (Parent (N)) /= N_Function_Call + then + -- If this is a tag-indeterminate call, the object must + -- be classwide. + + if Is_Tag_Indeterminate (N) then + Temp_Typ := Class_Wide_Type (Typ); + end if; + + else + -- If this is a dispatching call that is itself the + -- controlling argument of an enclosing call, the nominal + -- subtype of the object that replaces it must be classwide, + -- so that dispatching will take place properly. If it is + -- not a controlling argument, the object is not classwide. + + Proc := Entity (Name (Parent (N))); + F := First_Formal (Proc); + A := First_Actual (Parent (N)); + + while A /= N loop + Next_Formal (F); + Next_Actual (A); + end loop; + + if Is_Controlling_Formal (F) then + Temp_Typ := Class_Wide_Type (Typ); + end if; + end if; + end if; + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp_Obj, + Object_Definition => New_Occurrence_Of (Temp_Typ, Loc), + Constant_Present => True, + Expression => Relocate_Node (N)); + Set_Assignment_OK (Decl); + + Insert_Actions (N, New_List (Decl)); + Rewrite (N, New_Occurrence_Of (Temp_Obj, Loc)); + end; + + -- Normal case, expand the call + + else + Expand_Call (N); + end if; + end Expand_N_Function_Call; + + --------------------------------------- + -- Expand_N_Procedure_Call_Statement -- + --------------------------------------- + + procedure Expand_N_Procedure_Call_Statement (N : Node_Id) is + begin + Expand_Call (N); + end Expand_N_Procedure_Call_Statement; + + ------------------------------ + -- Expand_N_Subprogram_Body -- + ------------------------------ + + -- Add poll call if ATC polling is enabled + + -- Add return statement if last statement in body is not a return + -- statement (this makes things easier on Gigi which does not want + -- to have to handle a missing return). + + -- Add call to Activate_Tasks if body is a task activator + + -- Deal with possible detection of infinite recursion + + -- Eliminate body completely if convention stubbed + + -- Encode entity names within body, since we will not need to reference + -- these entities any longer in the front end. + + -- Initialize scalar out parameters if Initialize/Normalize_Scalars + + procedure Expand_N_Subprogram_Body (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + H : constant Node_Id := Handled_Statement_Sequence (N); + Spec_Id : Entity_Id; + Except_H : Node_Id; + Scop : Entity_Id; + Dec : Node_Id; + Next_Op : Node_Id; + L : List_Id; + + procedure Add_Return (S : List_Id); + -- Append a return statement to the statement sequence S if the last + -- statement is not already a return or a goto statement. Note that + -- the latter test is not critical, it does not matter if we add a + -- few extra returns, since they get eliminated anyway later on. + + ---------------- + -- Add_Return -- + ---------------- + + procedure Add_Return (S : List_Id) is + Last_S : constant Node_Id := Last (S); + -- Get original node, in case raise has been rewritten + + begin + if not Is_Transfer (Last_S) then + Append_To (S, Make_Return_Statement (Sloc (Last_S))); + end if; + end Add_Return; + + -- Start of processing for Expand_N_Subprogram_Body + + begin + -- Set L to either the list of declarations if present, or + -- to the list of statements if no declarations are present. + -- This is used to insert new stuff at the start. + + if Is_Non_Empty_List (Declarations (N)) then + L := Declarations (N); + else + L := Statements (Handled_Statement_Sequence (N)); + end if; + + -- Need poll on entry to subprogram if polling enabled. We only + -- do this for non-empty subprograms, since it does not seem + -- necessary to poll for a dummy null subprogram. + + if Is_Non_Empty_List (L) then + Generate_Poll_Call (First (L)); + end if; + + -- Find entity for subprogram + + if Present (Corresponding_Spec (N)) then + Spec_Id := Corresponding_Spec (N); + else + Spec_Id := Defining_Entity (N); + end if; + + -- Initialize any scalar OUT args if Initialize/Normalize_Scalars + + if Init_Or_Norm_Scalars and then Is_Subprogram (Spec_Id) then + declare + F : Entity_Id := First_Formal (Spec_Id); + V : constant Boolean := Validity_Checks_On; + + begin + -- We turn off validity checking, since we do not want any + -- check on the initializing value itself (which we know + -- may well be invalid!) + + Validity_Checks_On := False; + + -- Loop through formals + + while Present (F) loop + if Is_Scalar_Type (Etype (F)) + and then Ekind (F) = E_Out_Parameter + then + Insert_Before_And_Analyze (First (L), + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (F, Loc), + Expression => Get_Simple_Init_Val (Etype (F), Loc))); + end if; + + Next_Formal (F); + end loop; + + Validity_Checks_On := V; + end; + end if; + + -- Clear out statement list for stubbed procedure + + if Present (Corresponding_Spec (N)) then + Set_Elaboration_Flag (N, Spec_Id); + + if Convention (Spec_Id) = Convention_Stubbed + or else Is_Eliminated (Spec_Id) + then + Set_Declarations (N, Empty_List); + Set_Handled_Statement_Sequence (N, + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List ( + Make_Null_Statement (Loc)))); + return; + end if; + end if; + + Scop := Scope (Spec_Id); + + -- Returns_By_Ref flag is normally set when the subprogram is frozen + -- but subprograms with no specs are not frozen + + declare + Typ : constant Entity_Id := Etype (Spec_Id); + Utyp : constant Entity_Id := Underlying_Type (Typ); + + begin + if not Acts_As_Spec (N) + and then Nkind (Parent (Parent (Spec_Id))) /= + N_Subprogram_Body_Stub + then + null; + + elsif Is_Return_By_Reference_Type (Typ) then + Set_Returns_By_Ref (Spec_Id); + + elsif Present (Utyp) and then Controlled_Type (Utyp) then + Set_Returns_By_Ref (Spec_Id); + end if; + end; + + -- For a procedure, we add a return for all possible syntactic ends + -- of the subprogram. Note that reanalysis is not necessary in this + -- case since it would require a lot of work and accomplish nothing. + + if Ekind (Spec_Id) = E_Procedure + or else Ekind (Spec_Id) = E_Generic_Procedure + then + Add_Return (Statements (H)); + + if Present (Exception_Handlers (H)) then + Except_H := First_Non_Pragma (Exception_Handlers (H)); + + while Present (Except_H) loop + Add_Return (Statements (Except_H)); + Next_Non_Pragma (Except_H); + end loop; + end if; + + -- For a function, we must deal with the case where there is at + -- least one missing return. What we do is to wrap the entire body + -- of the function in a block: + + -- begin + -- ... + -- end; + + -- becomes + + -- begin + -- begin + -- ... + -- end; + + -- raise Program_Error; + -- end; + + -- This approach is necessary because the raise must be signalled + -- to the caller, not handled by any local handler (RM 6.4(11)). + + -- Note: we do not need to analyze the constructed sequence here, + -- since it has no handler, and an attempt to analyze the handled + -- statement sequence twice is risky in various ways (e.g. the + -- issue of expanding cleanup actions twice). + + elsif Has_Missing_Return (Spec_Id) then + declare + Hloc : constant Source_Ptr := Sloc (H); + Blok : constant Node_Id := + Make_Block_Statement (Hloc, + Handled_Statement_Sequence => H); + Rais : constant Node_Id := + Make_Raise_Program_Error (Hloc); + + begin + Set_Handled_Statement_Sequence (N, + Make_Handled_Sequence_Of_Statements (Hloc, + Statements => New_List (Blok, Rais))); + + New_Scope (Spec_Id); + Analyze (Blok); + Analyze (Rais); + Pop_Scope; + end; + end if; + + -- Add discriminal renamings to protected subprograms. + -- Install new discriminals for expansion of the next + -- subprogram of this protected type, if any. + + if Is_List_Member (N) + and then Present (Parent (List_Containing (N))) + and then Nkind (Parent (List_Containing (N))) = N_Protected_Body + then + Add_Discriminal_Declarations + (Declarations (N), Scop, Name_uObject, Loc); + Add_Private_Declarations (Declarations (N), Scop, Name_uObject, Loc); + + -- Associate privals and discriminals with the next protected + -- operation body to be expanded. These are used to expand + -- references to private data objects and discriminants, + -- respectively. + + Next_Op := Next_Protected_Operation (N); + + if Present (Next_Op) then + Dec := Parent (Base_Type (Scop)); + Set_Privals (Dec, Next_Op, Loc); + Set_Discriminals (Dec, Next_Op, Loc); + end if; + + end if; + + -- If subprogram contains a parameterless recursive call, then we may + -- have an infinite recursion, so see if we can generate code to check + -- for this possibility if storage checks are not suppressed. + + if Ekind (Spec_Id) = E_Procedure + and then Has_Recursive_Call (Spec_Id) + and then not Storage_Checks_Suppressed (Spec_Id) + then + Detect_Infinite_Recursion (N, Spec_Id); + end if; + + -- Finally, if we are in Normalize_Scalars mode, then any scalar out + -- parameters must be initialized to the appropriate default value. + + if Ekind (Spec_Id) = E_Procedure and then Normalize_Scalars then + declare + Floc : Source_Ptr; + Formal : Entity_Id; + Stm : Node_Id; + + begin + Formal := First_Formal (Spec_Id); + + while Present (Formal) loop + Floc := Sloc (Formal); + + if Ekind (Formal) = E_Out_Parameter + and then Is_Scalar_Type (Etype (Formal)) + then + Stm := + Make_Assignment_Statement (Floc, + Name => New_Occurrence_Of (Formal, Floc), + Expression => + Get_Simple_Init_Val (Etype (Formal), Floc)); + Prepend (Stm, Declarations (N)); + Analyze (Stm); + end if; + + Next_Formal (Formal); + end loop; + end; + end if; + + -- If the subprogram does not have pending instantiations, then we + -- must generate the subprogram descriptor now, since the code for + -- the subprogram is complete, and this is our last chance. However + -- if there are pending instantiations, then the code is not + -- complete, and we will delay the generation. + + if Is_Subprogram (Spec_Id) + and then not Delay_Subprogram_Descriptors (Spec_Id) + then + Generate_Subprogram_Descriptor_For_Subprogram (N, Spec_Id); + end if; + + -- Set to encode entity names in package body before gigi is called + + Qualify_Entity_Names (N); + end Expand_N_Subprogram_Body; + + ----------------------------------- + -- Expand_N_Subprogram_Body_Stub -- + ----------------------------------- + + procedure Expand_N_Subprogram_Body_Stub (N : Node_Id) is + begin + if Present (Corresponding_Body (N)) then + Expand_N_Subprogram_Body ( + Unit_Declaration_Node (Corresponding_Body (N))); + end if; + + end Expand_N_Subprogram_Body_Stub; + + ------------------------------------- + -- Expand_N_Subprogram_Declaration -- + ------------------------------------- + + -- The first task to be performed is the construction of default + -- expression functions for in parameters with default values. These + -- are parameterless inlined functions that are used to evaluate + -- default expressions that are more complicated than simple literals + -- or identifiers referencing constants and variables. + + -- If the declaration appears within a protected body, it is a private + -- operation of the protected type. We must create the corresponding + -- protected subprogram an associated formals. For a normal protected + -- operation, this is done when expanding the protected type declaration. + + procedure Expand_N_Subprogram_Declaration (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Subp : Entity_Id := Defining_Entity (N); + Scop : Entity_Id := Scope (Subp); + Prot_Sub : Entity_Id; + Prot_Bod : Node_Id; + + begin + -- Deal with case of protected subprogram + + if Is_List_Member (N) + and then Present (Parent (List_Containing (N))) + and then Nkind (Parent (List_Containing (N))) = N_Protected_Body + and then Is_Protected_Type (Scop) + then + if No (Protected_Body_Subprogram (Subp)) then + Prot_Sub := + Make_Subprogram_Declaration (Loc, + Specification => + Build_Protected_Sub_Specification + (N, Scop, Unprotected => True)); + + -- The protected subprogram is declared outside of the protected + -- body. Given that the body has frozen all entities so far, we + -- freeze the subprogram explicitly. If the body is a subunit, + -- the insertion point is before the stub in the parent. + + Prot_Bod := Parent (List_Containing (N)); + + if Nkind (Parent (Prot_Bod)) = N_Subunit then + Prot_Bod := Corresponding_Stub (Parent (Prot_Bod)); + end if; + + Insert_Before (Prot_Bod, Prot_Sub); + + New_Scope (Scope (Scop)); + Analyze (Prot_Sub); + Set_Protected_Body_Subprogram (Subp, + Defining_Unit_Name (Specification (Prot_Sub))); + Pop_Scope; + end if; + end if; + end Expand_N_Subprogram_Declaration; + + --------------------------------------- + -- Expand_Protected_Object_Reference -- + --------------------------------------- + + function Expand_Protected_Object_Reference + (N : Node_Id; + Scop : Entity_Id) + return Node_Id + is + Loc : constant Source_Ptr := Sloc (N); + Corr : Entity_Id; + Rec : Node_Id; + Param : Entity_Id; + Proc : Entity_Id; + + begin + Rec := Make_Identifier (Loc, Name_uObject); + Set_Etype (Rec, Corresponding_Record_Type (Scop)); + + -- Find enclosing protected operation, and retrieve its first + -- parameter, which denotes the enclosing protected object. + -- If the enclosing operation is an entry, we are immediately + -- within the protected body, and we can retrieve the object + -- from the service entries procedure. A barrier function has + -- has the same signature as an entry. A barrier function is + -- compiled within the protected object, but unlike protected + -- operations its never needs locks, so that its protected body + -- subprogram points to itself. + + Proc := Current_Scope; + + while Present (Proc) + and then Scope (Proc) /= Scop + loop + Proc := Scope (Proc); + end loop; + + Corr := Protected_Body_Subprogram (Proc); + + if No (Corr) then + + -- Previous error left expansion incomplete. + -- Nothing to do on this call. + + return Empty; + end if; + + Param := + Defining_Identifier + (First (Parameter_Specifications (Parent (Corr)))); + + if Is_Subprogram (Proc) + and then Proc /= Corr + then + -- Protected function or procedure. + + Set_Entity (Rec, Param); + + -- Rec is a reference to an entity which will not be in scope + -- when the call is reanalyzed, and needs no further analysis. + + Set_Analyzed (Rec); + + else + -- Entry or barrier function for entry body. + -- The first parameter of the entry body procedure is a + -- pointer to the object. We create a local variable + -- of the proper type, duplicating what is done to define + -- _object later on. + + declare + Decls : List_Id; + Obj_Ptr : Entity_Id := Make_Defining_Identifier + (Loc, New_Internal_Name ('T')); + begin + Decls := New_List ( + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Obj_Ptr, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + Subtype_Indication => + New_Reference_To + (Corresponding_Record_Type (Scop), Loc)))); + + Insert_Actions (N, Decls); + Insert_Actions (N, Freeze_Entity (Obj_Ptr, Sloc (N))); + + Rec := + Make_Explicit_Dereference (Loc, + Unchecked_Convert_To (Obj_Ptr, + New_Occurrence_Of (Param, Loc))); + + -- Analyze new actual. Other actuals in calls are already + -- analyzed and the list of actuals is not renalyzed after + -- rewriting. + + Set_Parent (Rec, N); + Analyze (Rec); + end; + end if; + + return Rec; + end Expand_Protected_Object_Reference; + + -------------------------------------- + -- Expand_Protected_Subprogram_Call -- + -------------------------------------- + + procedure Expand_Protected_Subprogram_Call + (N : Node_Id; + Subp : Entity_Id; + Scop : Entity_Id) + is + Rec : Node_Id; + + begin + -- If the protected object is not an enclosing scope, this is + -- an inter-object function call. Inter-object procedure + -- calls are expanded by Exp_Ch9.Build_Simple_Entry_Call. + -- The call is intra-object only if the subprogram being + -- called is in the protected body being compiled, and if the + -- protected object in the call is statically the enclosing type. + -- The object may be an component of some other data structure, + -- in which case this must be handled as an inter-object call. + + if not In_Open_Scopes (Scop) + or else not Is_Entity_Name (Name (N)) + then + if Nkind (Name (N)) = N_Selected_Component then + Rec := Prefix (Name (N)); + + else + pragma Assert (Nkind (Name (N)) = N_Indexed_Component); + Rec := Prefix (Prefix (Name (N))); + end if; + + Build_Protected_Subprogram_Call (N, + Name => New_Occurrence_Of (Subp, Sloc (N)), + Rec => Convert_Concurrent (Rec, Etype (Rec)), + External => True); + + else + Rec := Expand_Protected_Object_Reference (N, Scop); + + if No (Rec) then + return; + end if; + + Build_Protected_Subprogram_Call (N, + Name => Name (N), + Rec => Rec, + External => False); + + end if; + + Analyze (N); + + -- If it is a function call it can appear in elaboration code and + -- the called entity must be frozen here. + + if Ekind (Subp) = E_Function then + Freeze_Expression (Name (N)); + end if; + end Expand_Protected_Subprogram_Call; + + ----------------------- + -- Freeze_Subprogram -- + ----------------------- + + procedure Freeze_Subprogram (N : Node_Id) is + E : constant Entity_Id := Entity (N); + + begin + -- When a primitive is frozen, enter its name in the corresponding + -- dispatch table. If the DTC_Entity field is not set this is an + -- overridden primitive that can be ignored. We suppress the + -- initialization of the dispatch table entry when Java_VM because + -- the dispatching mechanism is handled internally by the JVM. + + if Is_Dispatching_Operation (E) + and then not Is_Abstract (E) + and then Present (DTC_Entity (E)) + and then not Is_CPP_Class (Scope (DTC_Entity (E))) + and then not Java_VM + then + Check_Overriding_Operation (E); + Insert_After (N, Fill_DT_Entry (Sloc (N), E)); + end if; + + -- Mark functions that return by reference. Note that it cannot be + -- part of the normal semantic analysis of the spec since the + -- underlying returned type may not be known yet (for private types) + + declare + Typ : constant Entity_Id := Etype (E); + Utyp : constant Entity_Id := Underlying_Type (Typ); + + begin + if Is_Return_By_Reference_Type (Typ) then + Set_Returns_By_Ref (E); + + elsif Present (Utyp) and then Controlled_Type (Utyp) then + Set_Returns_By_Ref (E); + end if; + end; + + end Freeze_Subprogram; + +end Exp_Ch6; |