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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- E X P _ C H 6 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2009, Free Software Foundation, Inc. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING3. If not, go to -- -- http://www.gnu.org/licenses for a complete copy of the license. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with 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_Atag; use Exp_Atag; 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_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 Exp_VFpt; use Exp_VFpt; with Fname; use Fname; with Freeze; use Freeze; with Inline; use Inline; with Lib; use Lib; with Namet; use Namet; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; with Restrict; use Restrict; with Rident; use Rident; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Aux; use Sem_Aux; 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_Eval; use Sem_Eval; with Sem_Disp; use Sem_Disp; with Sem_Dist; use Sem_Dist; with Sem_Mech; use Sem_Mech; with Sem_Res; use Sem_Res; with Sem_SCIL; use Sem_SCIL; 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 Add_Access_Actual_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Return_Object : Node_Id; Is_Access : Boolean := False); -- Ada 2005 (AI-318-02): Apply the Unrestricted_Access attribute to the -- object name given by Return_Object and add the attribute to the end of -- the actual parameter list associated with the build-in-place function -- call denoted by Function_Call. However, if Is_Access is True, then -- Return_Object is already an access expression, in which case it's passed -- along directly to the build-in-place function. Finally, if Return_Object -- is empty, then pass a null literal as the actual. procedure Add_Alloc_Form_Actual_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Alloc_Form : BIP_Allocation_Form := Unspecified; Alloc_Form_Exp : Node_Id := Empty); -- Ada 2005 (AI-318-02): Add an actual indicating the form of allocation, -- if any, to be done by a build-in-place function. If Alloc_Form_Exp is -- present, then use it, otherwise pass a literal corresponding to the -- Alloc_Form parameter (which must not be Unspecified in that case). procedure Add_Extra_Actual_To_Call (Subprogram_Call : Node_Id; Extra_Formal : Entity_Id; Extra_Actual : Node_Id); -- Adds Extra_Actual as a named parameter association for the formal -- Extra_Formal in Subprogram_Call. procedure Add_Final_List_Actual_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Acc_Type : Entity_Id; Sel_Comp : Node_Id := Empty); -- Ada 2005 (AI-318-02): For a build-in-place call, if the result type has -- controlled parts, add an actual parameter that is a pointer to -- appropriate finalization list. The finalization list is that of the -- current scope, except for "new Acc'(F(...))" in which case it's the -- finalization list of the access type returned by the allocator. Acc_Type -- is that type in the allocator case; Empty otherwise. If Sel_Comp is -- not Empty, then it denotes a selected component and the finalization -- list is obtained from the _controller list of the prefix object. procedure Add_Task_Actuals_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Master_Actual : Node_Id); -- Ada 2005 (AI-318-02): For a build-in-place call, if the result type -- contains tasks, add two actual parameters: the master, and a pointer to -- the caller's activation chain. Master_Actual is the actual parameter -- expression to pass for the master. In most cases, this is the current -- master (_master). The two exceptions are: If the function call is the -- initialization expression for an allocator, we pass the master of the -- access type. If the function call is the initialization expression for -- a return object, we pass along the master passed in by the caller. The -- activation chain to pass is always the local one. 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 or out parameter which is a numeric -- (view) 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 := TypeA (Temp); -- -- after the call. Here TypeA 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 : TypeA renames A; -- Temp : T := Var; -- omitting expression for out parameter. -- ... -- Var := TypeA (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. -- -- For non-scalar objects that are possibly unaligned, add call by copy -- code (copy in for IN and IN OUT, copy out for OUT and IN OUT). 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. function Is_Null_Procedure (Subp : Entity_Id) return Boolean; -- Predicate to recognize stubbed procedures and null procedures, which -- can be inlined unconditionally in all cases. ---------------------------------------------- -- Add_Access_Actual_To_Build_In_Place_Call -- ---------------------------------------------- procedure Add_Access_Actual_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Return_Object : Node_Id; Is_Access : Boolean := False) is Loc : constant Source_Ptr := Sloc (Function_Call); Obj_Address : Node_Id; Obj_Acc_Formal : Entity_Id; begin -- Locate the implicit access parameter in the called function Obj_Acc_Formal := Build_In_Place_Formal (Function_Id, BIP_Object_Access); -- If no return object is provided, then pass null if not Present (Return_Object) then Obj_Address := Make_Null (Loc); Set_Parent (Obj_Address, Function_Call); -- If Return_Object is already an expression of an access type, then use -- it directly, since it must be an access value denoting the return -- object, and couldn't possibly be the return object itself. elsif Is_Access then Obj_Address := Return_Object; Set_Parent (Obj_Address, Function_Call); -- Apply Unrestricted_Access to caller's return object else Obj_Address := Make_Attribute_Reference (Loc, Prefix => Return_Object, Attribute_Name => Name_Unrestricted_Access); Set_Parent (Return_Object, Obj_Address); Set_Parent (Obj_Address, Function_Call); end if; Analyze_And_Resolve (Obj_Address, Etype (Obj_Acc_Formal)); -- Build the parameter association for the new actual and add it to the -- end of the function's actuals. Add_Extra_Actual_To_Call (Function_Call, Obj_Acc_Formal, Obj_Address); end Add_Access_Actual_To_Build_In_Place_Call; -------------------------------------------------- -- Add_Alloc_Form_Actual_To_Build_In_Place_Call -- -------------------------------------------------- procedure Add_Alloc_Form_Actual_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Alloc_Form : BIP_Allocation_Form := Unspecified; Alloc_Form_Exp : Node_Id := Empty) is Loc : constant Source_Ptr := Sloc (Function_Call); Alloc_Form_Actual : Node_Id; Alloc_Form_Formal : Node_Id; begin -- The allocation form generally doesn't need to be passed in the case -- of a constrained result subtype, since normally the caller performs -- the allocation in that case. However this formal is still needed in -- the case where the function has a tagged result, because generally -- such functions can be called in a dispatching context and such calls -- must be handled like calls to class-wide functions. if Is_Constrained (Underlying_Type (Etype (Function_Id))) and then not Is_Tagged_Type (Underlying_Type (Etype (Function_Id))) then return; end if; -- Locate the implicit allocation form parameter in the called function. -- Maybe it would be better for each implicit formal of a build-in-place -- function to have a flag or a Uint attribute to identify it. ??? Alloc_Form_Formal := Build_In_Place_Formal (Function_Id, BIP_Alloc_Form); if Present (Alloc_Form_Exp) then pragma Assert (Alloc_Form = Unspecified); Alloc_Form_Actual := Alloc_Form_Exp; else pragma Assert (Alloc_Form /= Unspecified); Alloc_Form_Actual := Make_Integer_Literal (Loc, Intval => UI_From_Int (BIP_Allocation_Form'Pos (Alloc_Form))); end if; Analyze_And_Resolve (Alloc_Form_Actual, Etype (Alloc_Form_Formal)); -- Build the parameter association for the new actual and add it to the -- end of the function's actuals. Add_Extra_Actual_To_Call (Function_Call, Alloc_Form_Formal, Alloc_Form_Actual); end Add_Alloc_Form_Actual_To_Build_In_Place_Call; ------------------------------ -- Add_Extra_Actual_To_Call -- ------------------------------ procedure Add_Extra_Actual_To_Call (Subprogram_Call : Node_Id; Extra_Formal : Entity_Id; Extra_Actual : Node_Id) is Loc : constant Source_Ptr := Sloc (Subprogram_Call); Param_Assoc : Node_Id; begin Param_Assoc := Make_Parameter_Association (Loc, Selector_Name => New_Occurrence_Of (Extra_Formal, Loc), Explicit_Actual_Parameter => Extra_Actual); Set_Parent (Param_Assoc, Subprogram_Call); Set_Parent (Extra_Actual, Param_Assoc); if Present (Parameter_Associations (Subprogram_Call)) then if Nkind (Last (Parameter_Associations (Subprogram_Call))) = N_Parameter_Association then -- Find last named actual, and append declare L : Node_Id; begin L := First_Actual (Subprogram_Call); while Present (L) loop if No (Next_Actual (L)) then Set_Next_Named_Actual (Parent (L), Extra_Actual); exit; end if; Next_Actual (L); end loop; end; else Set_First_Named_Actual (Subprogram_Call, Extra_Actual); end if; Append (Param_Assoc, To => Parameter_Associations (Subprogram_Call)); else Set_Parameter_Associations (Subprogram_Call, New_List (Param_Assoc)); Set_First_Named_Actual (Subprogram_Call, Extra_Actual); end if; end Add_Extra_Actual_To_Call; -------------------------------------------------- -- Add_Final_List_Actual_To_Build_In_Place_Call -- -------------------------------------------------- procedure Add_Final_List_Actual_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Acc_Type : Entity_Id; Sel_Comp : Node_Id := Empty) is Loc : constant Source_Ptr := Sloc (Function_Call); Final_List : Node_Id; Final_List_Actual : Node_Id; Final_List_Formal : Node_Id; Is_Ctrl_Result : constant Boolean := Needs_Finalization (Underlying_Type (Etype (Function_Id))); begin -- No such extra parameter is needed if there are no controlled parts. -- The test for Needs_Finalization accounts for class-wide results -- (which potentially have controlled parts, even if the root type -- doesn't), and the test for a tagged result type is needed because -- calls to such a function can in general occur in dispatching -- contexts, which must be treated the same as a call to class-wide -- functions. Both of these situations require that a finalization list -- be passed. if not Needs_BIP_Final_List (Function_Id) then return; end if; -- Locate implicit finalization list parameter in the called function Final_List_Formal := Build_In_Place_Formal (Function_Id, BIP_Final_List); -- Create the actual which is a pointer to the appropriate finalization -- list. Acc_Type is present if and only if this call is the -- initialization of an allocator. Use the Current_Scope or the -- Acc_Type as appropriate. if Present (Acc_Type) and then (Ekind (Acc_Type) = E_Anonymous_Access_Type or else Present (Associated_Final_Chain (Base_Type (Acc_Type)))) then Final_List := Find_Final_List (Acc_Type); -- If Sel_Comp is present and the function result is controlled, then -- the finalization list will be obtained from the _controller list of -- the selected component's prefix object. elsif Present (Sel_Comp) and then Is_Ctrl_Result then Final_List := Find_Final_List (Current_Scope, Sel_Comp); else Final_List := Find_Final_List (Current_Scope); end if; Final_List_Actual := Make_Attribute_Reference (Loc, Prefix => Final_List, Attribute_Name => Name_Unrestricted_Access); Analyze_And_Resolve (Final_List_Actual, Etype (Final_List_Formal)); -- Build the parameter association for the new actual and add it to the -- end of the function's actuals. Add_Extra_Actual_To_Call (Function_Call, Final_List_Formal, Final_List_Actual); end Add_Final_List_Actual_To_Build_In_Place_Call; --------------------------------------------- -- Add_Task_Actuals_To_Build_In_Place_Call -- --------------------------------------------- procedure Add_Task_Actuals_To_Build_In_Place_Call (Function_Call : Node_Id; Function_Id : Entity_Id; Master_Actual : Node_Id) -- Note: Master_Actual can be Empty, but only if there are no tasks is Loc : constant Source_Ptr := Sloc (Function_Call); begin -- No such extra parameters are needed if there are no tasks if not Has_Task (Etype (Function_Id)) then return; end if; -- The master declare Master_Formal : Node_Id; begin -- Locate implicit master parameter in the called function Master_Formal := Build_In_Place_Formal (Function_Id, BIP_Master); Analyze_And_Resolve (Master_Actual, Etype (Master_Formal)); -- Build the parameter association for the new actual and add it to -- the end of the function's actuals. Add_Extra_Actual_To_Call (Function_Call, Master_Formal, Master_Actual); end; -- The activation chain declare Activation_Chain_Actual : Node_Id; Activation_Chain_Formal : Node_Id; begin -- Locate implicit activation chain parameter in the called function Activation_Chain_Formal := Build_In_Place_Formal (Function_Id, BIP_Activation_Chain); -- Create the actual which is a pointer to the current activation -- chain Activation_Chain_Actual := Make_Attribute_Reference (Loc, Prefix => Make_Identifier (Loc, Name_uChain), Attribute_Name => Name_Unrestricted_Access); Analyze_And_Resolve (Activation_Chain_Actual, Etype (Activation_Chain_Formal)); -- Build the parameter association for the new actual and add it to -- the end of the function's actuals. Add_Extra_Actual_To_Call (Function_Call, Activation_Chain_Formal, Activation_Chain_Actual); end; end Add_Task_Actuals_To_Build_In_Place_Call; ----------------------- -- BIP_Formal_Suffix -- ----------------------- function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String is begin case Kind is when BIP_Alloc_Form => return "BIPalloc"; when BIP_Final_List => return "BIPfinallist"; when BIP_Master => return "BIPmaster"; when BIP_Activation_Chain => return "BIPactivationchain"; when BIP_Object_Access => return "BIPaccess"; end case; end BIP_Formal_Suffix; --------------------------- -- Build_In_Place_Formal -- --------------------------- function Build_In_Place_Formal (Func : Entity_Id; Kind : BIP_Formal_Kind) return Entity_Id is Extra_Formal : Entity_Id := Extra_Formals (Func); begin -- Maybe it would be better for each implicit formal of a build-in-place -- function to have a flag or a Uint attribute to identify it. ??? loop pragma Assert (Present (Extra_Formal)); exit when Chars (Extra_Formal) = New_External_Name (Chars (Func), BIP_Formal_Suffix (Kind)); Next_Formal_With_Extras (Extra_Formal); end loop; return Extra_Formal; end Build_In_Place_Formal; -------------------------------- -- 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 : constant Elist_Id := New_Elmt_List; -- List of globals referenced by body of procedure Call_List : constant Elist_Id := New_Elmt_List; -- List of recursive calls in body of procedure Shad_List : constant 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 Treat_As_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 (Process); -- 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 Restriction_Active (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. Push_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, Reason => SE_Infinite_Recursion)), 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 cases 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. For an OUT or IN OUT parameter, -- an assignment is also generated to copy the result back. The call -- also takes care of any constraint checks required for the type -- conversion case (on both the way in and the way out). procedure Add_Simple_Call_By_Copy_Code; -- This is similar to the above, but is used in cases where we know -- that all that is needed is to simply create a temporary and copy -- the value in and out of the 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 Is_Legal_Copy return Boolean; -- Check that an actual can be copied before generating the temporary -- to be used in the call. If the actual is of a by_reference type then -- the program is illegal (this can only happen in the presence of -- rep. clauses that force an incorrect alignment). If the formal is -- a by_reference parameter imposed by a DEC pragma, emit a warning to -- the effect that this might lead to unaligned arguments. 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; Indic : Node_Id; Var : Entity_Id; F_Typ : constant Entity_Id := Etype (Formal); V_Typ : Entity_Id; Crep : Boolean; begin if not Is_Legal_Copy then return; end if; Temp := Make_Defining_Identifier (Loc, Chars => New_Internal_Name ('T')); -- Use formal type for temp, unless formal type is an unconstrained -- array, in which case we don't have to worry about bounds checks, -- and we use the actual type, since that has appropriate bounds. if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then Indic := New_Occurrence_Of (Etype (Actual), Loc); else Indic := New_Occurrence_Of (Etype (Formal), Loc); end if; if Nkind (Actual) = N_Type_Conversion then V_Typ := Etype (Expression (Actual)); -- If the formal is an (in-)out parameter, capture the name -- of the variable in order to build the post-call assignment. Var := Make_Var (Expression (Actual)); Crep := not Same_Representation (F_Typ, 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 this is an out parameter, the initial copy is wasteful, so as -- an optimization for the one-dimensional case we extract the -- bounds of the actual and build an uninitialized temporary of the -- right size. if Ekind (Formal) = E_In_Out_Parameter or else (Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ)) then if Nkind (Actual) = N_Type_Conversion then if Conversion_OK (Actual) then Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); else Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); end if; elsif Ekind (Formal) = E_Out_Parameter and then Is_Array_Type (F_Typ) and then Number_Dimensions (F_Typ) = 1 and then not Has_Non_Null_Base_Init_Proc (F_Typ) then -- Actual is a one-dimensional array or slice, and the type -- requires no initialization. Create a temporary of the -- right size, but do not copy actual into it (optimization). Init := Empty; Indic := Make_Subtype_Indication (Loc, Subtype_Mark => New_Occurrence_Of (F_Typ, Loc), Constraint => Make_Index_Or_Discriminant_Constraint (Loc, Constraints => New_List ( Make_Range (Loc, Low_Bound => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Var, Loc), Attribute_Name => Name_First), High_Bound => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Var, Loc), Attribute_Name => Name_Last))))); 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 (F_Typ) or else Is_Bit_Packed_Array (Etype (Expression (Actual)))) then if Conversion_OK (Actual) then Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); else Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); end if; elsif Ekind (Formal) = E_In_Parameter then -- Handle the case in which the actual is a type conversion if Nkind (Actual) = N_Type_Conversion then if Conversion_OK (Actual) then Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); else Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); end if; else Init := New_Occurrence_Of (Var, Loc); end if; else Init := Empty; end if; N_Node := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => Indic, 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; -- For IN parameter, all we do is to replace the actual if Ekind (Formal) = E_In_Parameter then Rewrite (Actual, New_Reference_To (Temp, Loc)); Analyze (Actual); -- Processing for OUT or IN OUT parameter else -- Kill current value indications for the temporary variable we -- created, since we just passed it as an OUT parameter. Kill_Current_Values (Temp); Set_Is_Known_Valid (Temp, False); -- 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); -- If the actual is a conversion of a packed reference, it may -- already have been expanded by Remove_Side_Effects, and the -- resulting variable is a temporary which does not designate -- the proper out-parameter, which may not be addressable. In -- that case, generate an assignment to the original expression -- (before expansion of the packed reference) so that the proper -- expansion of assignment to a packed component can take place. declare Obj : Node_Id; Lhs : Node_Id; begin if Is_Renaming_Of_Object (Var) and then Nkind (Renamed_Object (Var)) = N_Selected_Component and then Is_Entity_Name (Prefix (Renamed_Object (Var))) and then Nkind (Original_Node (Prefix (Renamed_Object (Var)))) = N_Indexed_Component and then Has_Non_Standard_Rep (Etype (Prefix (Renamed_Object (Var)))) then Obj := Renamed_Object (Var); Lhs := Make_Selected_Component (Loc, Prefix => New_Copy_Tree (Original_Node (Prefix (Obj))), Selector_Name => New_Copy (Selector_Name (Obj))); Reset_Analyzed_Flags (Lhs); else Lhs := New_Occurrence_Of (Var, Loc); end if; Set_Assignment_OK (Lhs); Append_To (Post_Call, Make_Assignment_Statement (Loc, Name => Lhs, Expression => Expr)); end; end if; end Add_Call_By_Copy_Code; ---------------------------------- -- Add_Simple_Call_By_Copy_Code -- ---------------------------------- procedure Add_Simple_Call_By_Copy_Code is Temp : Entity_Id; Decl : Node_Id; Incod : Node_Id; Outcod : Node_Id; Lhs : Node_Id; Rhs : Node_Id; Indic : Node_Id; F_Typ : constant Entity_Id := Etype (Formal); begin if not Is_Legal_Copy then return; end if; -- Use formal type for temp, unless formal type is an unconstrained -- array, in which case we don't have to worry about bounds checks, -- and we use the actual type, since that has appropriate bounds. if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then Indic := New_Occurrence_Of (Etype (Actual), Loc); else Indic := New_Occurrence_Of (Etype (Formal), Loc); end if; -- Prepare to generate code Reset_Packed_Prefix; Temp := Make_Defining_Identifier (Loc, Chars => 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 formal or -- this is an initialization call. -- If the formal is an out parameter with discriminants, the -- discriminants must be captured even if the rest of the object -- is in principle uninitialized, because the discriminants may -- be read by the called subprogram. if Ekind (Formal) = E_Out_Parameter then Incod := Empty; if Has_Discriminants (Etype (Formal)) then Indic := New_Occurrence_Of (Etype (Actual), Loc); end if; elsif Inside_Init_Proc then -- Could use a comment here to match comment below ??? if Nkind (Actual) /= N_Selected_Component or else not Has_Discriminant_Dependent_Constraint (Entity (Selector_Name (Actual))) then Incod := Empty; -- Otherwise, keep the component in order to generate the proper -- actual subtype, that depends on enclosing discriminants. else null; end if; end if; Decl := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => Indic, Expression => Incod); if Inside_Init_Proc and then No (Incod) then -- If the call is to initialize a component of a composite type, -- and the component does not depend on discriminants, use the -- actual type of the component. This is required in case the -- component is constrained, because in general the formal of the -- initialization procedure will be unconstrained. Note that if -- the component being initialized is constrained by an enclosing -- discriminant, the presence of the initialization in the -- declaration will generate an expression for the actual subtype. Set_No_Initialization (Decl); Set_Object_Definition (Decl, New_Occurrence_Of (Etype (Actual), Loc)); end if; Insert_Action (N, Decl); -- 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)); Set_Assignment_OK (Name (Last (Post_Call))); end if; end Add_Simple_Call_By_Copy_Code; --------------------------- -- Check_Fortran_Logical -- --------------------------- procedure Check_Fortran_Logical is Logical : constant 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; ------------------- -- Is_Legal_Copy -- ------------------- function Is_Legal_Copy return Boolean is begin -- An attempt to copy a value of such a type can only occur if -- representation clauses give the actual a misaligned address. if Is_By_Reference_Type (Etype (Formal)) then Error_Msg_N ("misaligned actual cannot be passed by reference", Actual); return False; -- For users of Starlet, we assume that the specification of by- -- reference mechanism is mandatory. This may lead to unaligned -- objects but at least for DEC legacy code it is known to work. -- The warning will alert users of this code that a problem may -- be lurking. elsif Mechanism (Formal) = By_Reference and then Is_Valued_Procedure (Scope (Formal)) then Error_Msg_N ("by_reference actual may be misaligned?", Actual); return False; else return True; end if; end Is_Legal_Copy; -------------- -- 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, Chars => 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 not Nkind_In (Pfx, N_Selected_Component, N_Indexed_Component); Pfx := Prefix (Pfx); end loop; end Reset_Packed_Prefix; -- Start of processing for Expand_Actuals begin Post_Call := New_List; Formal := First_Formal (Subp); Actual := First_Actual (N); 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; -- Ada 2005 (AI-318-02): If the actual parameter is a call to a -- build-in-place function, then a temporary return object needs -- to be created and access to it must be passed to the function. -- Currently we limit such functions to those with inherently -- limited result subtypes, but eventually we plan to expand the -- functions that are treated as build-in-place to include other -- composite result types. if Ada_Version >= Ada_05 and then Is_Build_In_Place_Function_Call (Actual) then Make_Build_In_Place_Call_In_Anonymous_Context (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_Simple_Call_By_Copy_Code; -- If a non-scalar actual is possibly bit-aligned, we need a copy -- because the back-end cannot cope with such objects. In other -- cases where alignment forces a copy, the back-end generates -- it properly. It should not be generated unconditionally in the -- front-end because it does not know precisely the alignment -- requirements of the target, and makes too conservative an -- estimate, leading to superfluous copies or spurious errors -- on by-reference parameters. elsif Nkind (Actual) = N_Selected_Component and then Component_May_Be_Bit_Aligned (Entity (Selector_Name (Actual))) and then not Represented_As_Scalar (Etype (Formal)) then Add_Simple_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; -- References to possibly unaligned slices of arrays are expanded elsif Is_Possibly_Unaligned_Slice (Actual) then Add_Call_By_Copy_Code; -- Deal with access types where the actual subtype and the -- formal subtype are not the same, requiring a check. -- It is necessary to exclude tagged types because of "downward -- conversion" errors. 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; -- If the actual is not a scalar and is marked for volatile -- treatment, whereas the formal is not volatile, then pass -- by copy unless it is a by-reference type. -- Note: we use Is_Volatile here rather than Treat_As_Volatile, -- because this is the enforcement of a language rule that applies -- only to "real" volatile variables, not e.g. to the address -- clause overlay case. elsif Is_Entity_Name (Actual) and then Is_Volatile (Entity (Actual)) and then not Is_By_Reference_Type (Etype (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; -- Add call-by-copy code for the case of scalar out parameters -- when it is not known at compile time that the subtype of the -- formal is a subrange of the subtype of the actual (or vice -- versa for in out parameters), in order to get range checks -- on such actuals. (Maybe this case should be handled earlier -- in the if statement???) elsif Is_Scalar_Type (E_Formal) and then (not In_Subrange_Of (E_Formal, Etype (Actual)) or else (Ekind (Formal) = E_In_Out_Parameter and then not In_Subrange_Of (Etype (Actual), E_Formal))) then -- Perhaps the setting back to False should be done within -- Add_Call_By_Copy_Code, since it could get set on other -- cases occurring above??? if Do_Range_Check (Actual) then Set_Do_Range_Check (Actual, False); end if; Add_Call_By_Copy_Code; end if; -- Processing for IN parameters else -- For IN parameters is in the packed array case, we expand an -- 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.) if Nkind (Actual) = N_Indexed_Component and then Is_Packed (Etype (Prefix (Actual))) then Reset_Packed_Prefix; Expand_Packed_Element_Reference (Actual); -- If we have a reference to a bit packed array, we copy it, since -- the actual must be byte aligned. -- Is this really necessary in all cases??? elsif Is_Ref_To_Bit_Packed_Array (Actual) then Add_Simple_Call_By_Copy_Code; -- If a non-scalar actual is possibly unaligned, we need a copy elsif Is_Possibly_Unaligned_Object (Actual) and then not Represented_As_Scalar (Etype (Formal)) then Add_Simple_Call_By_Copy_Code; -- Similarly, we have to expand slices of packed arrays here -- because the result must be byte aligned. elsif Is_Ref_To_Bit_Packed_Slice (Actual) then Add_Call_By_Copy_Code; -- Only processing remaining is to pass by copy if this is a -- reference to a possibly unaligned slice, since the caller -- expects an appropriately aligned argument. elsif Is_Possibly_Unaligned_Slice (Actual) then Add_Call_By_Copy_Code; 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_In (P, N_Triggering_Alternative, 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); Extra_Actuals : List_Id := No_List; Prev : Node_Id := Empty; 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. 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 No (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)); if Nkind (N) = N_Function_Call then Set_Is_Accessibility_Actual (Parent (Expr)); end if; 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 or else not In_Instance 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)) then return Empty; else Gen_Par := Generic_Parent_Type (Parent (Par)); end if; -- If the actual has no generic parent type, the formal is not -- a formal derived type, so nothing to inherit. if No (Gen_Par) then return Empty; end if; -- If the generic parent type is still the generic type, this is a -- private formal, not a derived formal, and there are no operations -- inherited from the formal. if Nkind (Parent (Gen_Par)) = N_Formal_Type_Declaration then return Empty; 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; -- Local variables Remote : constant Boolean := Is_Remote_Call (N); Actual : Node_Id; Formal : Entity_Id; Orig_Subp : Entity_Id := Empty; Param_Count : Natural := 0; Parent_Formal : Entity_Id; Parent_Subp : Entity_Id; Scop : Entity_Id; Subp : Entity_Id; Prev_Orig : Node_Id; -- Original node for an actual, which may have been rewritten. If the -- actual is a function call that has been transformed from a selected -- component, the original node is unanalyzed. Otherwise, it carries -- semantic information used to generate additional actuals. CW_Interface_Formals_Present : Boolean := False; -- Start of processing for Expand_Call begin -- Ignore if previous error if Nkind (N) in N_Has_Etype and then Etype (N) = Any_Type then return; end if; -- 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. -- This improves efficiency by avoiding a run-time test. -- We do not do this if Raise_Exception_Always does not exist, which -- can happen in configurable run time profiles which provide only a -- Raise_Exception. if Is_RTE (Subp, RE_Raise_Exception) and then RTE_Available (RE_Raise_Exception_Always) 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_Name (N, New_Occurrence_Of (Subp, Loc)); end if; end; end if; if Ekind (Subp) = E_Entry then Parent_Subp := Empty; end if; end if; -- Ada 2005 (AI-345): We have a procedure call as a triggering -- alternative in an asynchronous select or as an entry call in -- a conditional or timed select. Check whether the procedure call -- is a renaming of an entry and rewrite it as an entry call. if Ada_Version >= Ada_05 and then Nkind (N) = N_Procedure_Call_Statement and then ((Nkind (Parent (N)) = N_Triggering_Alternative and then Triggering_Statement (Parent (N)) = N) or else (Nkind (Parent (N)) = N_Entry_Call_Alternative and then Entry_Call_Statement (Parent (N)) = N)) then declare Ren_Decl : Node_Id; Ren_Root : Entity_Id := Subp; begin -- This may be a chain of renamings, find the root if Present (Alias (Ren_Root)) then Ren_Root := Alias (Ren_Root); end if; if Present (Original_Node (Parent (Parent (Ren_Root)))) then Ren_Decl := Original_Node (Parent (Parent (Ren_Root))); if Nkind (Ren_Decl) = N_Subprogram_Renaming_Declaration then Rewrite (N, Make_Entry_Call_Statement (Loc, Name => New_Copy_Tree (Name (Ren_Decl)), Parameter_Associations => New_Copy_List_Tree (Parameter_Associations (N)))); return; end if; end if; end; 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 collecting corresponding actuals in Extra_Actuals. -- We also generate any required range checks for actuals for in formals -- as we go through the loop, since this is a convenient place to do it. -- (Though it seems that this would be better done in Expand_Actuals???) Formal := First_Formal (Subp); Actual := First_Actual (N); Param_Count := 1; while Present (Formal) loop -- Generate range check if required if Do_Range_Check (Actual) and then Ekind (Formal) = E_In_Parameter then Set_Do_Range_Check (Actual, False); Generate_Range_Check (Actual, Etype (Formal), CE_Range_Check_Failed); end if; -- Prepare to examine current entry Prev := Actual; Prev_Orig := Original_Node (Prev); -- Ada 2005 (AI-251): Check if any formal is a class-wide interface -- to expand it in a further round. CW_Interface_Formals_Present := CW_Interface_Formals_Present or else (Ekind (Etype (Formal)) = E_Class_Wide_Type and then Is_Interface (Etype (Etype (Formal)))) or else (Ekind (Etype (Formal)) = E_Anonymous_Access_Type and then Is_Interface (Directly_Designated_Type (Etype (Etype (Formal))))); -- 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)); -- Do not produce extra actuals for Unchecked_Union parameters. -- Jump directly to the end of the loop. elsif Is_Unchecked_Union (Base_Type (Etype (Actual))) then goto Skip_Extra_Actual_Generation; 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; begin -- Test for unchecked conversions as well, which can occur -- as out parameter actuals on calls to stream procedures. Act_Prev := Prev; while Nkind_In (Act_Prev, N_Type_Conversion, N_Unchecked_Type_Conversion) loop Act_Prev := Expression (Act_Prev); end loop; -- If the expression is a conversion of a dereference, this -- is internally generated code that manipulates addresses, -- e.g. when building interface tables. No check should -- occur in this case, and the discriminated object is not -- directly a hand. if not Comes_From_Source (Actual) and then Nkind (Actual) = N_Unchecked_Type_Conversion and then Nkind (Act_Prev) = N_Explicit_Dereference then Add_Extra_Actual (New_Occurrence_Of (Standard_False, Loc), Extra_Constrained (Formal)); else Add_Extra_Actual (Make_Attribute_Reference (Sloc (Prev), Prefix => Duplicate_Subexpr_No_Checks (Act_Prev, Name_Req => True), Attribute_Name => Name_Constrained), Extra_Constrained (Formal)); end if; end; end if; end if; -- Create possible extra actual for accessibility level if Present (Extra_Accessibility (Formal)) then -- Ada 2005 (AI-252): If the actual was rewritten as an Access -- attribute, then the original actual may be an aliased object -- occurring as the prefix in a call using "Object.Operation" -- notation. In that case we must pass the level of the object, -- so Prev_Orig is reset to Prev and the attribute will be -- processed by the code for Access attributes further below. if Prev_Orig /= Prev and then Nkind (Prev) = N_Attribute_Reference and then Get_Attribute_Id (Attribute_Name (Prev)) = Attribute_Access and then Is_Aliased_View (Prev_Orig) then Prev_Orig := Prev; end if; -- Ada 2005 (AI-251): Thunks must propagate the extra actuals -- of accessibility levels. if Ekind (Current_Scope) in Subprogram_Kind and then Is_Thunk (Current_Scope) then declare Parm_Ent : Entity_Id; begin if Is_Controlling_Actual (Actual) then -- Find the corresponding actual of the thunk Parm_Ent := First_Entity (Current_Scope); for J in 2 .. Param_Count loop Next_Entity (Parm_Ent); end loop; else pragma Assert (Is_Entity_Name (Actual)); Parm_Ent := Entity (Actual); end if; Add_Extra_Actual (New_Occurrence_Of (Extra_Accessibility (Parm_Ent), Loc), Extra_Accessibility (Formal)); end; elsif Is_Entity_Name (Prev_Orig) then -- When passing an access parameter, or a renaming of an access -- parameter, as the actual to another access parameter we need -- to pass along the actual's own access level parameter. This -- is done if we are within the scope of the formal access -- parameter (if this is an inlined body the extra formal is -- irrelevant). if (Is_Formal (Entity (Prev_Orig)) or else (Present (Renamed_Object (Entity (Prev_Orig))) and then Is_Entity_Name (Renamed_Object (Entity (Prev_Orig))) and then Is_Formal (Entity (Renamed_Object (Entity (Prev_Orig)))))) 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; -- If the actual is an access discriminant, then pass the level -- of the enclosing object (RM05-3.10.2(12.4/2)). elsif Nkind (Prev_Orig) = N_Selected_Component and then Ekind (Entity (Selector_Name (Prev_Orig))) = E_Discriminant and then Ekind (Etype (Entity (Selector_Name (Prev_Orig)))) = E_Anonymous_Access_Type then Add_Extra_Actual (Make_Integer_Literal (Loc, Intval => Object_Access_Level (Prefix (Prev_Orig))), Extra_Accessibility (Formal)); -- All other cases 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, Intval => Scope_Depth (Current_Scope) + 1), Extra_Accessibility (Formal)); -- For other cases we simply pass the level of the actual's -- access type. The type is retrieved from Prev rather than -- Prev_Orig, because in some cases Prev_Orig denotes an -- original expression that has not been analyzed. when others => Add_Extra_Actual (Make_Integer_Literal (Loc, Intval => Type_Access_Level (Etype (Prev))), 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 Ada_Version >= Ada_05 then -- Ada 2005 (AI-231): Check null-excluding access types if Is_Access_Type (Etype (Formal)) and then Can_Never_Be_Null (Etype (Formal)) and then Nkind (Prev) /= N_Raise_Constraint_Error and then (Known_Null (Prev) or else not Can_Never_Be_Null (Etype (Prev))) then Install_Null_Excluding_Check (Prev); end if; -- Ada_Version < Ada_05 else if Ekind (Etype (Formal)) /= E_Anonymous_Access_Type or else Access_Checks_Suppressed (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_In (Prev, N_Allocator, N_Attribute_Reference) then null; -- Suppress null checks when passing to access parameters of Java -- and CIL subprograms. (Should this be done for other foreign -- conventions as well ???) elsif Convention (Subp) = Convention_Java or else Convention (Subp) = Convention_CIL then null; else Install_Null_Excluding_Check (Prev); end if; end if; -- Perform appropriate validity checks on parameters that -- are entities. if Validity_Checks_On then if (Ekind (Formal) = E_In_Parameter and then Validity_Check_In_Params) or else (Ekind (Formal) = E_In_Out_Parameter and then Validity_Check_In_Out_Params) then -- If the actual is an indexed component of a packed type (or -- is an indexed or selected component whose prefix recursively -- meets this condition), it has not been expanded yet. It will -- be copied in the validity code that follows, and has to be -- expanded appropriately, so reanalyze it. -- What we do is just to unset analyzed bits on prefixes till -- we reach something that does not have a prefix. declare Nod : Node_Id; begin Nod := Actual; while Nkind_In (Nod, N_Indexed_Component, N_Selected_Component) loop Set_Analyzed (Nod, False); Nod := Prefix (Nod); end loop; end; 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; -- Mark any scalar OUT parameter that is a simple variable as no -- longer known to be valid (unless the type is always valid). This -- reflects the fact that if an OUT parameter is never set in a -- procedure, then it can become invalid on the procedure return. if Ekind (Formal) = E_Out_Parameter and then Is_Entity_Name (Actual) and then Ekind (Entity (Actual)) = E_Variable and then not Is_Known_Valid (Etype (Actual)) then Set_Is_Known_Valid (Entity (Actual), False); end if; -- For an OUT or IN OUT parameter, if the actual is an entity, then -- clear current values, since they can be clobbered. We are probably -- doing this in more places than we need to, but better safe than -- sorry when it comes to retaining bad current values! if Ekind (Formal) /= E_In_Parameter and then Is_Entity_Name (Actual) and then Present (Entity (Actual)) then declare Ent : constant Entity_Id := Entity (Actual); Sav : Node_Id; begin -- For an OUT or IN OUT parameter that is an assignable entity, -- we do not want to clobber the Last_Assignment field, since -- if it is set, it was precisely because it is indeed an OUT -- or IN OUT parameter! We do reset the Is_Known_Valid flag -- since the subprogram could have returned in invalid value. if (Ekind (Formal) = E_Out_Parameter or else Ekind (Formal) = E_In_Out_Parameter) and then Is_Assignable (Ent) then Sav := Last_Assignment (Ent); Kill_Current_Values (Ent); Set_Last_Assignment (Ent, Sav); Set_Is_Known_Valid (Ent, False); -- For all other cases, just kill the current values else Kill_Current_Values (Ent); end if; end; 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_Transportable_Check (Loc, Duplicate_Subexpr_Move_Checks (Actual))); end if; -- This label is required when skipping extra actual generation for -- Unchecked_Union parameters. <<Skip_Extra_Actual_Generation>> Param_Count := Param_Count + 1; Next_Actual (Actual); Next_Formal (Formal); end loop; -- If we are expanding a rhs of an assignment we need to check if tag -- propagation is needed. You might expect this processing to be in -- Analyze_Assignment but has to be done earlier (bottom-up) because the -- assignment might be transformed to a declaration for an unconstrained -- 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)); elsif Nkind (Parent (N)) = N_Explicit_Dereference 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 if Is_Access_Type (Etype (N)) then if Designated_Type (Etype (N)) /= Root_Type (Etype (Name (Ass))) then Error_Msg_NE ("tag-indeterminate expression " & " must have designated type& (RM 5.2 (6))", N, Root_Type (Etype (Name (Ass)))); else Propagate_Tag (Name (Ass), N); end if; elsif Etype (N) /= Root_Type (Etype (Name (Ass))) then Error_Msg_NE ("tag-indeterminate expression must have type&" & "(RM 5.2 (6))", N, Root_Type (Etype (Name (Ass)))); else Propagate_Tag (Name (Ass), N); end if; -- The call will be rewritten as a dispatching call, and -- expanded as such. return; end if; end; end if; -- Ada 2005 (AI-251): If some formal is a class-wide interface, expand -- it to point to the correct secondary virtual table if Nkind_In (N, N_Function_Call, N_Procedure_Call_Statement) and then CW_Interface_Formals_Present then Expand_Interface_Actuals (N); 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 VM_Target, because -- the VM back-ends directly handle the generation of dispatching -- calls and would have to undo any expansion to an indirect call. if Nkind_In (N, N_Function_Call, N_Procedure_Call_Statement) and then Present (Controlling_Argument (N)) then if Tagged_Type_Expansion then Expand_Dispatching_Call (N); -- The following return is worrisome. Is it really OK to -- skip all remaining processing in this procedure ??? return; else Apply_Tag_Checks (N); -- Expansion of a dispatching call results in an indirect call, -- which in turn causes current values to be killed (see -- Resolve_Call), so on VM targets we do the call here to ensure -- consistent warnings between VM and non-VM targets. Kill_Current_Values; end if; end if; -- 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 rewriting to occur in expanded code. if 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; -- At this point we have all the actuals, so this is the point at -- which the various expansion activities for actuals is carried out. Expand_Actuals (N, Subp); -- 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; -- The below setting of Entity is suspect, see F109-018 discussion??? Set_Entity (Name (N), Parent_Subp); if Is_Abstract_Subprogram (Parent_Subp) and then not In_Instance then Error_Msg_NE ("cannot call abstract subprogram &!", Name (N), Parent_Subp); end if; -- Inspect all formals of derived subprogram Subp. Compare parameter -- types with the parent subprogram and check whether an actual may -- need a type conversion to the corresponding formal of the parent -- subprogram. -- Not clear whether intrinsic subprograms need such conversions. ??? if not Is_Intrinsic_Subprogram (Parent_Subp) or else Is_Generic_Instance (Parent_Subp) then declare procedure Convert (Act : Node_Id; Typ : Entity_Id); -- Rewrite node Act as a type conversion of Act to Typ. Analyze -- and resolve the newly generated construct. ------------- -- Convert -- ------------- procedure Convert (Act : Node_Id; Typ : Entity_Id) is begin Rewrite (Act, OK_Convert_To (Typ, Relocate_Node (Act))); Analyze (Act); Resolve (Act, Typ); end Convert; -- Local variables Actual_Typ : Entity_Id; Formal_Typ : Entity_Id; Parent_Typ : Entity_Id; begin Actual := First_Actual (N); Formal := First_Formal (Subp); Parent_Formal := First_Formal (Parent_Subp); while Present (Formal) loop Actual_Typ := Etype (Actual); Formal_Typ := Etype (Formal); Parent_Typ := Etype (Parent_Formal); -- For an IN parameter of a scalar type, the parent formal -- type and derived formal type differ or the parent formal -- type and actual type do not match statically. if Is_Scalar_Type (Formal_Typ) and then Ekind (Formal) = E_In_Parameter and then Formal_Typ /= Parent_Typ and then not Subtypes_Statically_Match (Parent_Typ, Actual_Typ) and then not Raises_Constraint_Error (Actual) then Convert (Actual, Parent_Typ); Enable_Range_Check (Actual); -- If the actual has been marked as requiring a range -- check, then generate it here. if Do_Range_Check (Actual) then Set_Do_Range_Check (Actual, False); Generate_Range_Check (Actual, Etype (Formal), CE_Range_Check_Failed); end if; -- For access types, the parent formal type and actual type -- differ. elsif Is_Access_Type (Formal_Typ) and then Base_Type (Parent_Typ) /= Base_Type (Actual_Typ) then if Ekind (Formal) /= E_In_Parameter then Convert (Actual, Parent_Typ); elsif Ekind (Parent_Typ) = E_Anonymous_Access_Type and then Designated_Type (Parent_Typ) /= Designated_Type (Actual_Typ) and then not Is_Controlling_Formal (Formal) then -- This unchecked conversion is not necessary unless -- inlining is enabled, because in that case the type -- mismatch may become visible in the body about to be -- inlined. Rewrite (Actual, Unchecked_Convert_To (Parent_Typ, Relocate_Node (Actual))); -- If the relocated node is a function call then it -- can be part of the expansion of the predefined -- equality operator of a tagged type and we may -- need to adjust its SCIL dispatching node. if Generate_SCIL and then Nkind (Actual) /= N_Null and then Nkind (Expression (Actual)) = N_Function_Call then Adjust_SCIL_Node (Actual, Expression (Actual)); end if; Analyze (Actual); Resolve (Actual, Parent_Typ); end if; -- For array and record types, the parent formal type and -- derived formal type have different sizes or pragma Pack -- status. elsif ((Is_Array_Type (Formal_Typ) and then Is_Array_Type (Parent_Typ)) or else (Is_Record_Type (Formal_Typ) and then Is_Record_Type (Parent_Typ))) and then (Esize (Formal_Typ) /= Esize (Parent_Typ) or else Has_Pragma_Pack (Formal_Typ) /= Has_Pragma_Pack (Parent_Typ)) then Convert (Actual, Parent_Typ); end if; Next_Actual (Actual); Next_Formal (Formal); Next_Formal (Parent_Formal); end loop; end; end if; Orig_Subp := Subp; Subp := Parent_Subp; end if; -- Check for violation of No_Abort_Statements if Is_RTE (Subp, RE_Abort_Task) then Check_Restriction (No_Abort_Statements, N); -- Check for violation of No_Dynamic_Attachment elsif RTU_Loaded (Ada_Interrupts) and then (Is_RTE (Subp, RE_Is_Reserved) or else Is_RTE (Subp, RE_Is_Attached) or else Is_RTE (Subp, RE_Current_Handler) or else Is_RTE (Subp, RE_Attach_Handler) or else Is_RTE (Subp, RE_Exchange_Handler) or else Is_RTE (Subp, RE_Detach_Handler) or else Is_RTE (Subp, RE_Reference)) then Check_Restriction (No_Dynamic_Attachment, N); end if; -- Deal with case where call is an explicit dereference if Nkind (Name (N)) = N_Explicit_Dereference then -- Handle case of access to protected subprogram type if Is_Access_Protected_Subprogram_Type (Base_Type (Etype (Prefix (Name (N))))) 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 : constant Node_Id := Prefix (Name (N)); T : constant Entity_Id := Equivalent_Type (Base_Type (Etype (Ptr))); D_T : constant 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, Prefix => 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!) -- In the case where the intrinsic is to be processed by the back end, -- the call to Expand_Intrinsic_Call will do nothing, which is fine, -- since the idea in this case is to pass the call unchanged. -- If the intrinsic is an inherited unchecked conversion, and the -- derived type is the target type of the conversion, we must retain -- it as the return type of the expression. Otherwise the expansion -- below, which uses the parent operation, will yield the wrong type. if Is_Intrinsic_Subprogram (Subp) then Expand_Intrinsic_Call (N, Subp); if Nkind (N) = N_Unchecked_Type_Conversion and then Parent_Subp /= Orig_Subp and then Etype (Parent_Subp) /= Etype (Orig_Subp) then Set_Etype (N, Etype (Orig_Subp)); end if; return; end if; if Ekind (Subp) = E_Function or else Ekind (Subp) = E_Procedure then -- We perform two simple optimization on calls: -- a) replace calls to null procedures unconditionally; -- b) for To_Address, just do an unchecked conversion. Not only is -- this efficient, but it also avoids order of elaboration problems -- when address clauses are inlined (address expression elaborated -- at the wrong point). -- We perform these optimization regardless of whether we are in the -- main unit or in a unit in the context of the main unit, to ensure -- that tree generated is the same in both cases, for Inspector use. if Is_RTE (Subp, RE_To_Address) then Rewrite (N, Unchecked_Convert_To (RTE (RE_Address), Relocate_Node (First_Actual (N)))); return; elsif Is_Null_Procedure (Subp) then Rewrite (N, Make_Null_Statement (Loc)); return; end if; if Is_Inlined (Subp) then Inlined_Subprogram : declare Bod : Node_Id; Must_Inline : Boolean := False; Spec : constant Node_Id := Unit_Declaration_Node (Subp); Scop : constant Entity_Id := Scope (Subp); function In_Unfrozen_Instance return Boolean; -- If the subprogram comes from an instance in the same unit, -- and the instance is not yet frozen, inlining might trigger -- order-of-elaboration problems in gigi. -------------------------- -- In_Unfrozen_Instance -- -------------------------- function In_Unfrozen_Instance return Boolean is S : Entity_Id; begin S := Scop; while Present (S) and then S /= Standard_Standard loop if Is_Generic_Instance (S) and then Present (Freeze_Node (S)) and then not Analyzed (Freeze_Node (S)) then return True; end if; S := Scope (S); end loop; return False; end In_Unfrozen_Instance; -- Start of processing for Inlined_Subprogram 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 the back end. -- This should be documented in sinfo/einfo ??? if No (Spec) or else Nkind (Spec) /= N_Subprogram_Declaration or else No (Body_To_Inline (Spec)) then Must_Inline := False; -- If this an inherited function that returns a private type, -- do not inline if the full view is an unconstrained array, -- because such calls cannot be inlined. elsif Present (Orig_Subp) and then Is_Array_Type (Etype (Orig_Subp)) and then not Is_Constrained (Etype (Orig_Subp)) then Must_Inline := False; elsif In_Unfrozen_Instance then Must_Inline := False; else Bod := Body_To_Inline (Spec); if (In_Extended_Main_Code_Unit (N) or else In_Extended_Main_Code_Unit (Parent (N)) or else Has_Pragma_Inline_Always (Subp)) and then (not In_Same_Extended_Unit (Sloc (Bod), Loc) or else Earlier_In_Extended_Unit (Sloc (Bod), Loc)) then Must_Inline := True; -- If we are compiling a package body that is not the main -- unit, it must be for inlining/instantiation purposes, -- in which case we inline the call to insure that the same -- temporaries are generated when compiling the body by -- itself. Otherwise link errors can occur. -- If the function being called is itself in the main unit, -- we cannot inline, because there is a risk of double -- elaboration and/or circularity: the inlining can make -- visible a private entity in the body of the main unit, -- that gigi will see before its sees its proper definition. elsif not (In_Extended_Main_Code_Unit (N)) and then In_Package_Body then Must_Inline := not In_Extended_Main_Source_Unit (Subp); end if; end if; if Must_Inline 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) then Cannot_Inline ("cannot inline& (body not seen yet)?", N, Subp); end if; end if; end Inlined_Subprogram; end if; end if; -- Check for 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. -- In Ada 2005, this may be an indirect call to an access parameter that -- is an access_to_subprogram. In that case the anonymous type has a -- scope that is a protected operation, but the call is a regular one. Scop := Scope (Subp); if Nkind (N) /= N_Entry_Call_Statement and then Is_Protected_Type (Scop) and then Ekind (Subp) /= E_Subprogram_Type then -- If the call is an internal one, it is rewritten as a call to the -- corresponding unprotected subprogram. Expand_Protected_Subprogram_Call (N, Subp, Scop); end if; -- Functions returning controlled objects need special attention: -- if the return type is limited, the context is an initialization -- and different processing applies. If the call is to a protected -- function, the expansion above will call Expand_Call recusively. -- To prevent a double attachment, check that the current call is -- not a rewriting of a protected function call. if Needs_Finalization (Etype (Subp)) and then not Is_Inherently_Limited_Type (Etype (Subp)) and then (No (First_Formal (Subp)) or else not Is_Concurrent_Record_Type (Etype (First_Formal (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 kept. -- 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; -- 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 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 Discard_Node (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; 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 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))); 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); Is_Predef : constant Boolean := Is_Predefined_File_Name (Unit_File_Name (Get_Source_Unit (Subp))); Orig_Bod : constant Node_Id := Body_To_Inline (Unit_Declaration_Node (Subp)); Blk : Node_Id; Bod : Node_Id; Decl : Node_Id; Decls : constant List_Id := New_List; 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; Ret_Type : Entity_Id; Targ : Node_Id; Targ1 : Node_Id; Temp : Entity_Id; Temp_Typ : Entity_Id; Is_Unc : constant Boolean := Is_Array_Type (Etype (Subp)) and then not Is_Constrained (Etype (Subp)); -- If the type returned by the function is unconstrained and the call -- can be inlined, special processing is required. procedure Make_Exit_Label; -- Build declaration for exit label to be used in Return statements, -- sets Exit_Lab (the label node) and Lab_Decl (corresponding implcit -- declaration). function Process_Formals (N : Node_Id) return Traverse_Result; -- Replace occurrence of a formal with the corresponding actual, or the -- thunk generated for it. function Process_Sloc (Nod : Node_Id) return Traverse_Result; -- If the call being expanded is that of an internal subprogram, set the -- sloc of the generated block to that of the call itself, so that the -- expansion is skipped by the "next" command in gdb. -- Same processing for a subprogram in a predefined file, e.g. -- Ada.Tags. If Debug_Generated_Code is true, suppress this change to -- simplify our own development. 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. function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean; -- Determine whether a formal parameter is used only once in Orig_Bod --------------------- -- Make_Exit_Label -- --------------------- procedure Make_Exit_Label is begin -- Create exit label for subprogram if one does not exist yet if No (Exit_Lab) then Lab_Id := Make_Identifier (Loc, Chars => 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); -- Rewrite the occurrence of the formal into an occurrence of -- the actual. Also establish visibility on the proper view of -- the actual's subtype for the body's context (if the actual's -- subtype is private at the call point but its full view is -- visible to the body, then the inlined tree here must be -- analyzed with the full view). if Is_Entity_Name (A) then Rewrite (N, New_Occurrence_Of (Entity (A), Loc)); Check_Private_View (N); elsif Nkind (A) = N_Defining_Identifier then Rewrite (N, New_Occurrence_Of (A, Loc)); Check_Private_View (N); -- Numeric literal else Rewrite (N, New_Copy (A)); end if; end if; return Skip; elsif Nkind (N) = N_Simple_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, e.g. 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_In (Expression (N), N_Aggregate, N_Null) 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; -- Remove pragma Unreferenced since it may refer to formals that -- are not visible in the inlined body, and in any case we will -- not be posting warnings on the inlined body so it is unneeded. elsif Nkind (N) = N_Pragma and then Pragma_Name (N) = Name_Unreferenced then Rewrite (N, Make_Null_Statement (Sloc (N))); return OK; else return OK; end if; end Process_Formals; procedure Replace_Formals is new Traverse_Proc (Process_Formals); ------------------ -- Process_Sloc -- ------------------ function Process_Sloc (Nod : Node_Id) return Traverse_Result is begin if not Debug_Generated_Code then Set_Sloc (Nod, Sloc (N)); Set_Comes_From_Source (Nod, False); end if; return OK; end Process_Sloc; procedure Reset_Slocs is new Traverse_Proc (Process_Sloc); --------------------------- -- Rewrite_Function_Call -- --------------------------- procedure Rewrite_Function_Call (N : Node_Id; Blk : Node_Id) is HSS : constant Node_Id := Handled_Statement_Sequence (Blk); Fst : constant 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))) or else (Nkind (Name (Parent (N))) = N_Explicit_Dereference and then Is_Entity_Name (Prefix (Name (Parent (N)))))) then -- Replace assignment with the block declare Original_Assignment : constant Node_Id := Parent (N); begin -- Preserve the original assignment node to keep the complete -- assignment subtree consistent enough for Analyze_Assignment -- to proceed (specifically, the original Lhs node must still -- have an assignment statement as its parent). -- We cannot rely on Original_Node to go back from the block -- node to the assignment node, because the assignment might -- already be a rewrite substitution. Discard_Node (Relocate_Node (Original_Assignment)); Rewrite (Original_Assignment, Blk); end; elsif Nkind (Parent (N)) = N_Object_Declaration then Set_Expression (Parent (N), Empty); Insert_After (Parent (N), Blk); elsif Is_Unc then Insert_Before (Parent (N), Blk); end if; end Rewrite_Function_Call; ---------------------------- -- Rewrite_Procedure_Call -- ---------------------------- procedure Rewrite_Procedure_Call (N : Node_Id; Blk : Node_Id) is HSS : constant Node_Id := Handled_Statement_Sequence (Blk); begin -- If there is a transient scope for N, this will be the scope of the -- actions for N, and the statements in Blk need to be within this -- scope. For example, they need to have visibility on the constant -- declarations created for the formals. -- If N needs no transient scope, and if there are no declarations in -- the inlined body, we can do a little optimization and insert the -- statements for the body directly after N, and rewrite N to a -- null statement, instead of rewriting N into a full-blown block -- statement. if not Scope_Is_Transient and then 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; ------------------------- -- Formal_Is_Used_Once -- ------------------------- function Formal_Is_Used_Once (Formal : Entity_Id) return Boolean is Use_Counter : Int := 0; function Count_Uses (N : Node_Id) return Traverse_Result; -- Traverse the tree and count the uses of the formal parameter. -- In this case, for optimization purposes, we do not need to -- continue the traversal once more than one use is encountered. ---------------- -- Count_Uses -- ---------------- function Count_Uses (N : Node_Id) return Traverse_Result is begin -- The original node is an identifier if Nkind (N) = N_Identifier and then Present (Entity (N)) -- Original node's entity points to the one in the copied body and then Nkind (Entity (N)) = N_Identifier and then Present (Entity (Entity (N))) -- The entity of the copied node is the formal parameter and then Entity (Entity (N)) = Formal then Use_Counter := Use_Counter + 1; if Use_Counter > 1 then -- Denote more than one use and abandon the traversal Use_Counter := 2; return Abandon; end if; end if; return OK; end Count_Uses; procedure Count_Formal_Uses is new Traverse_Proc (Count_Uses); -- Start of processing for Formal_Is_Used_Once begin Count_Formal_Uses (Orig_Bod); return Use_Counter = 1; end Formal_Is_Used_Once; -- Start of processing for Expand_Inlined_Call begin -- Check for an illegal attempt to inline a recursive procedure. If the -- subprogram has parameters this is detected when trying to supply a -- binding for parameters that already have one. For parameterless -- subprograms this must be done explicitly. if In_Open_Scopes (Subp) then Error_Msg_N ("call to recursive subprogram cannot be inlined?", N); Set_Is_Inlined (Subp, False); return; end if; if Nkind (Orig_Bod) = N_Defining_Identifier or else Nkind (Orig_Bod) = N_Defining_Operator_Symbol 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. If -- the renamed subprogram is an inherited operation, we must redo -- the expansion because implicit conversions may be needed. Set_Name (N, New_Occurrence_Of (Orig_Bod, Loc)); if Present (Alias (Orig_Bod)) then Expand_Call (N); end if; 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_For_Inlined_Body (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; -- For the unconstrained case, capture the name of the local -- variable that holds the result. This must be the first declaration -- in the block, because its bounds cannot depend on local variables. -- Otherwise there is no way to declare the result outside of the -- block. Needless to say, in general the bounds will depend on the -- actuals in the call. if Is_Unc then Targ1 := Defining_Identifier (First (Declarations (Blk))); 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; -- Create temporaries for the actuals that are expressions, or that -- are scalars and require copying to preserve semantics. F := First_Formal (Subp); A := First_Actual (N); 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 the actual is a simple name or a literal, no need to -- create a temporary, object can be used directly. -- If the actual is a literal and the formal has its address taken, -- we cannot pass the literal itself as an argument, so its value -- must be captured in a temporary. if (Is_Entity_Name (A) and then (not Is_Scalar_Type (Etype (A)) or else Ekind (Entity (A)) = E_Enumeration_Literal)) -- When the actual is an identifier and the corresponding formal -- is used only once in the original body, the formal can be -- substituted directly with the actual parameter. or else (Nkind (A) = N_Identifier and then Formal_Is_Used_Once (F)) or else (Nkind_In (A, N_Real_Literal, N_Integer_Literal, N_Character_Literal) and then not Address_Taken (F)) then 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; else 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_Parameter 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 the actual has a by-reference type, it cannot be copied, so -- its value is captured in a renaming declaration. Otherwise -- declare a local constant initialized with the actual. -- We also use a renaming declaration for expressions of an array -- type that is not bit-packed, both for efficiency reasons and to -- respect the semantics of the call: in most cases the original -- call will pass the parameter by reference, and thus the inlined -- code will have the same semantics. if Ekind (F) = E_In_Parameter and then not Is_Limited_Type (Etype (A)) and then not Is_Tagged_Type (Etype (A)) and then (not Is_Array_Type (Etype (A)) or else not Is_Object_Reference (A) or else Is_Bit_Packed_Array (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; Append (Decl, Decls); Set_Renamed_Object (F, Temp); 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, i.e. an entity or an explicit dereference of one. 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)); elsif Nkind (Parent (N)) = N_Assignment_Statement and then Nkind (Name (Parent (N))) = N_Explicit_Dereference and then Is_Entity_Name (Prefix (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')); Set_Is_Internal (Temp); -- For the unconstrained case, the generated temporary has the -- same constrained declaration as the result variable. It may -- eventually be possible to remove that temporary and use the -- result variable directly. if Is_Unc then Decl := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => New_Copy_Tree (Object_Definition (Parent (Targ1)))); Replace_Formals (Decl); else Decl := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => New_Occurrence_Of (Ret_Type, Loc)); Set_Etype (Temp, Ret_Type); end if; Set_No_Initialization (Decl); Append (Decl, Decls); Rewrite (N, New_Occurrence_Of (Temp, Loc)); Targ := Temp; end if; end if; Insert_Actions (N, Decls); -- 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 not Comes_From_Source (Subp) or else Is_Predef then Reset_Slocs (Blk); end if; 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. If this is a -- predefined unit, analyze with checks off, as is done in the non- -- inlined run-time units. declare I_Flag : constant Boolean := In_Inlined_Body; begin In_Inlined_Body := True; if Is_Predef then declare Style : constant Boolean := Style_Check; begin Style_Check := False; Analyze (Blk, Suppress => All_Checks); Style_Check := Style; end; else Analyze (Blk); end if; In_Inlined_Body := I_Flag; end; if Ekind (Subp) = E_Procedure then Rewrite_Procedure_Call (N, Blk); else Rewrite_Function_Call (N, Blk); -- For the unconstrained case, the replacement of the call has been -- made prior to the complete analysis of the generated declarations. -- Propagate the proper type now. if Is_Unc then if Nkind (N) = N_Identifier then Set_Etype (N, Etype (Entity (N))); else Set_Etype (N, Etype (Targ1)); end if; end if; 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 begin Expand_Call (N); -- If the return value of a foreign compiled function is VAX Float, then -- expand the return (adjusts the location of the return value on -- Alpha/VMS, no-op everywhere else). -- Comes_From_Source intercepts recursive expansion. if Vax_Float (Etype (N)) and then Nkind (N) = N_Function_Call and then Present (Name (N)) and then Present (Entity (Name (N))) and then Has_Foreign_Convention (Entity (Name (N))) and then Comes_From_Source (Parent (N)) then Expand_Vax_Foreign_Return (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, unless the body will be inlined -- by the back-end. -- Add dummy push/pop label nodes at start and end to clear any local -- exception indications if local-exception-to-goto optimization is active. -- 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 -- Reset Pure indication if any parameter has root type System.Address -- Wrap thread body procedure Expand_N_Subprogram_Body (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); H : constant Node_Id := Handled_Statement_Sequence (N); Body_Id : Entity_Id; Except_H : Node_Id; L : List_Id; Spec_Id : Entity_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_Stm : Node_Id; Loc : Source_Ptr; begin -- Get last statement, ignoring any Pop_xxx_Label nodes, which are -- not relevant in this context since they are not executable. Last_Stm := Last (S); while Nkind (Last_Stm) in N_Pop_xxx_Label loop Prev (Last_Stm); end loop; -- Now insert return unless last statement is a transfer if not Is_Transfer (Last_Stm) then -- The source location for the return is the end label of the -- procedure if present. Otherwise use the sloc of the last -- statement in the list. If the list comes from a generated -- exception handler and we are not debugging generated code, -- all the statements within the handler are made invisible -- to the debugger. if Nkind (Parent (S)) = N_Exception_Handler and then not Comes_From_Source (Parent (S)) then Loc := Sloc (Last_Stm); elsif Present (End_Label (H)) then Loc := Sloc (End_Label (H)); else Loc := Sloc (Last_Stm); end if; declare Rtn : constant Node_Id := Make_Simple_Return_Statement (Loc); begin -- Append return statement, and set analyzed manually. We can't -- call Analyze on this return since the scope is wrong. -- Note: it almost works to push the scope and then do the -- Analyze call, but something goes wrong in some weird cases -- and it is not worth worrying about ??? Append_To (S, Rtn); Set_Analyzed (Rtn); -- Call _Postconditions procedure if appropriate. We need to -- do this explicitly because we did not analyze the generated -- return statement above, so the call did not get inserted. if Ekind (Spec_Id) = E_Procedure and then Has_Postconditions (Spec_Id) then pragma Assert (Present (Postcondition_Proc (Spec_Id))); Insert_Action (Rtn, Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (Postcondition_Proc (Spec_Id), Loc))); end if; end; 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 (H); end if; -- If local-exception-to-goto optimization active, insert dummy push -- statements at start, and dummy pop statements at end. if (Debug_Flag_Dot_G or else Restriction_Active (No_Exception_Propagation)) and then Is_Non_Empty_List (L) then declare FS : constant Node_Id := First (L); FL : constant Source_Ptr := Sloc (FS); LS : Node_Id; LL : Source_Ptr; begin -- LS points to either last statement, if statements are present -- or to the last declaration if there are no statements present. -- It is the node after which the pop's are generated. if Is_Non_Empty_List (Statements (H)) then LS := Last (Statements (H)); else LS := Last (L); end if; LL := Sloc (LS); Insert_List_Before_And_Analyze (FS, New_List ( Make_Push_Constraint_Error_Label (FL), Make_Push_Program_Error_Label (FL), Make_Push_Storage_Error_Label (FL))); Insert_List_After_And_Analyze (LS, New_List ( Make_Pop_Constraint_Error_Label (LL), Make_Pop_Program_Error_Label (LL), Make_Pop_Storage_Error_Label (LL))); end; end if; -- Find entity for subprogram Body_Id := Defining_Entity (N); if Present (Corresponding_Spec (N)) then Spec_Id := Corresponding_Spec (N); else Spec_Id := Body_Id; 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 -- Do not add a polling call if the subprogram is to be inlined by -- the back-end, to avoid repeated calls with multiple inlinings. if Is_Inlined (Spec_Id) and then Front_End_Inlining and then Optimization_Level > 1 then null; else Generate_Poll_Call (First (L)); end if; end if; -- If this is a Pure function which has any parameters whose root type -- is System.Address, reset the Pure indication, since it will likely -- cause incorrect code to be generated as the parameter is probably -- a pointer, and the fact that the same pointer is passed does not mean -- that the same value is being referenced. -- Note that if the programmer gave an explicit Pure_Function pragma, -- then we believe the programmer, and leave the subprogram Pure. -- This code should probably be at the freeze point, so that it happens -- even on a -gnatc (or more importantly -gnatt) compile, so that the -- semantic tree has Is_Pure set properly ??? if Is_Pure (Spec_Id) and then Is_Subprogram (Spec_Id) and then not Has_Pragma_Pure_Function (Spec_Id) then declare F : Entity_Id; begin F := First_Formal (Spec_Id); while Present (F) loop if Is_Descendent_Of_Address (Etype (F)) then Set_Is_Pure (Spec_Id, False); if Spec_Id /= Body_Id then Set_Is_Pure (Body_Id, False); end if; exit; end if; Next_Formal (F); end loop; end; 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; begin -- Loop through formals F := First_Formal (Spec_Id); while Present (F) loop if Is_Scalar_Type (Etype (F)) and then Ekind (F) = E_Out_Parameter then Check_Restriction (No_Default_Initialization, F); -- Insert the initialization. We turn off validity checks -- for this assignment, since we do not want any check on -- the initial value itself (which may well be invalid). Insert_Before_And_Analyze (First (L), Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (F, Loc), Expression => Get_Simple_Init_Val (Etype (F), N)), Suppress => Validity_Check); end if; Next_Formal (F); end loop; 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; -- Create a set of discriminals for the next protected subprogram body if Is_List_Member (N) and then Present (Parent (List_Containing (N))) and then Nkind (Parent (List_Containing (N))) = N_Protected_Body and then Present (Next_Protected_Operation (N)) then Set_Discriminals (Parent (Base_Type (Scope (Spec_Id)))); end if; -- 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_Inherently_Limited_Type (Typ) then Set_Returns_By_Ref (Spec_Id); elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (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. 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, Reason => PE_Missing_Return); begin Set_Handled_Statement_Sequence (N, Make_Handled_Sequence_Of_Statements (Hloc, Statements => New_List (Blok, Rais))); Push_Scope (Spec_Id); Analyze (Blok); Analyze (Rais); Pop_Scope; end; 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; -- 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 -- ------------------------------------- -- 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. -- If the declaration is for a null procedure, emit null body procedure Expand_N_Subprogram_Declaration (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Subp : constant Entity_Id := Defining_Entity (N); Scop : constant Entity_Id := Scope (Subp); Prot_Decl : Node_Id; Prot_Bod : Node_Id; Prot_Id : Entity_Id; begin -- Deal with case of protected subprogram. Do not generate protected -- operation if operation is flagged as eliminated. 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)) and then not Is_Eliminated (Subp) then Prot_Decl := Make_Subprogram_Declaration (Loc, Specification => Build_Protected_Sub_Specification (N, Scop, Unprotected_Mode)); -- The protected subprogram is declared outside of the protected -- body. Given that the body has frozen all entities so far, we -- analyze the subprogram and perform freezing actions explicitly. -- including the generation of an explicit freeze node, to ensure -- that gigi has the proper order of elaboration. -- 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_Decl); Prot_Id := Defining_Unit_Name (Specification (Prot_Decl)); Set_Has_Delayed_Freeze (Prot_Id); Push_Scope (Scope (Scop)); Analyze (Prot_Decl); Insert_Actions (N, Freeze_Entity (Prot_Id, Loc)); Set_Protected_Body_Subprogram (Subp, Prot_Id); -- Create protected operation as well. Even though the operation -- is only accessible within the body, it is possible to make it -- available outside of the protected object by using 'Access to -- provide a callback, so build protected version in all cases. Prot_Decl := Make_Subprogram_Declaration (Loc, Specification => Build_Protected_Sub_Specification (N, Scop, Protected_Mode)); Insert_Before (Prot_Bod, Prot_Decl); Analyze (Prot_Decl); Pop_Scope; end if; -- Ada 2005 (AI-348): Generate body for a null procedure. -- In most cases this is superfluous because calls to it -- will be automatically inlined, but we definitely need -- the body if preconditions for the procedure are present. elsif Nkind (Specification (N)) = N_Procedure_Specification and then Null_Present (Specification (N)) then declare Bod : constant Node_Id := Body_To_Inline (N); begin Set_Has_Completion (Subp, False); Append_Freeze_Action (Subp, Bod); -- The body now contains raise statements, so calls to it will -- not be inlined. Set_Is_Inlined (Subp, False); end; 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, Chars => 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 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 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 : constant Entity_Id := Make_Defining_Identifier (Loc, Chars => 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 reanalyzed 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; -- 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; -- Analyze and resolve the new call. The actuals have already been -- resolved, but expansion of a function call will add extra actuals -- if needed. Analysis of a procedure call already includes resolution. Analyze (N); if Ekind (Subp) = E_Function then Resolve (N, Etype (Subp)); end if; end Expand_Protected_Subprogram_Call; -------------------------------- -- Is_Build_In_Place_Function -- -------------------------------- function Is_Build_In_Place_Function (E : Entity_Id) return Boolean is begin -- For now we test whether E denotes a function or access-to-function -- type whose result subtype is inherently limited. Later this test may -- be revised to allow composite nonlimited types. Functions with a -- foreign convention or whose result type has a foreign convention -- never qualify. if Ekind (E) = E_Function or else Ekind (E) = E_Generic_Function or else (Ekind (E) = E_Subprogram_Type and then Etype (E) /= Standard_Void_Type) then -- Note: If you have Convention (C) on an inherently limited type, -- you're on your own. That is, the C code will have to be carefully -- written to know about the Ada conventions. if Has_Foreign_Convention (E) or else Has_Foreign_Convention (Etype (E)) then return False; -- In Ada 2005 all functions with an inherently limited return type -- must be handled using a build-in-place profile, including the case -- of a function with a limited interface result, where the function -- may return objects of nonlimited descendants. else return Is_Inherently_Limited_Type (Etype (E)) and then Ada_Version >= Ada_05 and then not Debug_Flag_Dot_L; end if; else return False; end if; end Is_Build_In_Place_Function; ------------------------------------- -- Is_Build_In_Place_Function_Call -- ------------------------------------- function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean is Exp_Node : Node_Id := N; Function_Id : Entity_Id; begin -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Exp_Node, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Exp_Node := Expression (N); end if; if Nkind (Exp_Node) /= N_Function_Call then return False; else if Is_Entity_Name (Name (Exp_Node)) then Function_Id := Entity (Name (Exp_Node)); elsif Nkind (Name (Exp_Node)) = N_Explicit_Dereference then Function_Id := Etype (Name (Exp_Node)); end if; return Is_Build_In_Place_Function (Function_Id); end if; end Is_Build_In_Place_Function_Call; ----------------------- -- Freeze_Subprogram -- ----------------------- procedure Freeze_Subprogram (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); procedure Register_Predefined_DT_Entry (Prim : Entity_Id); -- (Ada 2005): Register a predefined primitive in all the secondary -- dispatch tables of its primitive type. ---------------------------------- -- Register_Predefined_DT_Entry -- ---------------------------------- procedure Register_Predefined_DT_Entry (Prim : Entity_Id) is Iface_DT_Ptr : Elmt_Id; Tagged_Typ : Entity_Id; Thunk_Id : Entity_Id; Thunk_Code : Node_Id; begin Tagged_Typ := Find_Dispatching_Type (Prim); if No (Access_Disp_Table (Tagged_Typ)) or else not Has_Interfaces (Tagged_Typ) or else not RTE_Available (RE_Interface_Tag) or else Restriction_Active (No_Dispatching_Calls) then return; end if; -- Skip the first two access-to-dispatch-table pointers since they -- leads to the primary dispatch table (predefined DT and user -- defined DT). We are only concerned with the secondary dispatch -- table pointers. Note that the access-to- dispatch-table pointer -- corresponds to the first implemented interface retrieved below. Iface_DT_Ptr := Next_Elmt (Next_Elmt (First_Elmt (Access_Disp_Table (Tagged_Typ)))); while Present (Iface_DT_Ptr) and then Ekind (Node (Iface_DT_Ptr)) = E_Constant loop pragma Assert (Has_Thunks (Node (Iface_DT_Ptr))); Expand_Interface_Thunk (Prim, Thunk_Id, Thunk_Code); if Present (Thunk_Code) then Insert_Actions_After (N, New_List ( Thunk_Code, Build_Set_Predefined_Prim_Op_Address (Loc, Tag_Node => New_Reference_To (Node (Next_Elmt (Iface_DT_Ptr)), Loc), Position => DT_Position (Prim), Address_Node => Unchecked_Convert_To (RTE (RE_Prim_Ptr), Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Thunk_Id, Loc), Attribute_Name => Name_Unrestricted_Access))), Build_Set_Predefined_Prim_Op_Address (Loc, Tag_Node => New_Reference_To (Node (Next_Elmt (Next_Elmt (Next_Elmt (Iface_DT_Ptr)))), Loc), Position => DT_Position (Prim), Address_Node => Unchecked_Convert_To (RTE (RE_Prim_Ptr), Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Prim, Loc), Attribute_Name => Name_Unrestricted_Access))))); end if; -- Skip the tag of the predefined primitives dispatch table Next_Elmt (Iface_DT_Ptr); pragma Assert (Has_Thunks (Node (Iface_DT_Ptr))); -- Skip the tag of the no-thunks dispatch table Next_Elmt (Iface_DT_Ptr); pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr))); -- Skip the tag of the predefined primitives no-thunks dispatch -- table Next_Elmt (Iface_DT_Ptr); pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr))); Next_Elmt (Iface_DT_Ptr); end loop; end Register_Predefined_DT_Entry; -- Local variables Subp : constant Entity_Id := Entity (N); -- Start of processing for Freeze_Subprogram begin -- We suppress the initialization of the dispatch table entry when -- VM_Target because the dispatching mechanism is handled internally -- by the VM. if Is_Dispatching_Operation (Subp) and then not Is_Abstract_Subprogram (Subp) and then Present (DTC_Entity (Subp)) and then Present (Scope (DTC_Entity (Subp))) and then Tagged_Type_Expansion and then not Restriction_Active (No_Dispatching_Calls) and then RTE_Available (RE_Tag) then declare Typ : constant Entity_Id := Scope (DTC_Entity (Subp)); begin -- Handle private overridden primitives if not Is_CPP_Class (Typ) then Check_Overriding_Operation (Subp); end if; -- We assume that imported CPP primitives correspond with objects -- whose constructor is in the CPP side; therefore we don't need -- to generate code to register them in the dispatch table. if Is_CPP_Class (Typ) then null; -- Handle CPP primitives found in derivations of CPP_Class types. -- These primitives must have been inherited from some parent, and -- there is no need to register them in the dispatch table because -- Build_Inherit_Prims takes care of the initialization of these -- slots. elsif Is_Imported (Subp) and then (Convention (Subp) = Convention_CPP or else Convention (Subp) = Convention_C) then null; -- Generate code to register the primitive in non statically -- allocated dispatch tables elsif not Static_Dispatch_Tables or else not Is_Library_Level_Tagged_Type (Scope (DTC_Entity (Subp))) then -- When a primitive is frozen, enter its name in its dispatch -- table slot. if not Is_Interface (Typ) or else Present (Interface_Alias (Subp)) then if Is_Predefined_Dispatching_Operation (Subp) then Register_Predefined_DT_Entry (Subp); end if; Insert_Actions_After (N, Register_Primitive (Loc, Prim => Subp)); end if; end if; end; 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 (Subp); Utyp : constant Entity_Id := Underlying_Type (Typ); begin if Is_Inherently_Limited_Type (Typ) then Set_Returns_By_Ref (Subp); elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then Set_Returns_By_Ref (Subp); end if; end; end Freeze_Subprogram; ----------------------- -- Is_Null_Procedure -- ----------------------- function Is_Null_Procedure (Subp : Entity_Id) return Boolean is Decl : constant Node_Id := Unit_Declaration_Node (Subp); begin if Ekind (Subp) /= E_Procedure then return False; -- Check if this is a declared null procedure elsif Nkind (Decl) = N_Subprogram_Declaration then if not Null_Present (Specification (Decl)) then return False; elsif No (Body_To_Inline (Decl)) then return False; -- Check if the body contains only a null statement, followed by -- the return statement added during expansion. else declare Orig_Bod : constant Node_Id := Body_To_Inline (Decl); Stat : Node_Id; Stat2 : Node_Id; begin if Nkind (Orig_Bod) /= N_Subprogram_Body then return False; else -- We must skip SCIL nodes because they are currently -- implemented as special N_Null_Statement nodes. Stat := First_Non_SCIL_Node (Statements (Handled_Statement_Sequence (Orig_Bod))); Stat2 := Next_Non_SCIL_Node (Stat); return Is_Empty_List (Declarations (Orig_Bod)) and then Nkind (Stat) = N_Null_Statement and then (No (Stat2) or else (Nkind (Stat2) = N_Simple_Return_Statement and then No (Next (Stat2)))); end if; end; end if; else return False; end if; end Is_Null_Procedure; ------------------------------------------- -- Make_Build_In_Place_Call_In_Allocator -- ------------------------------------------- procedure Make_Build_In_Place_Call_In_Allocator (Allocator : Node_Id; Function_Call : Node_Id) is Loc : Source_Ptr; Func_Call : Node_Id := Function_Call; Function_Id : Entity_Id; Result_Subt : Entity_Id; Acc_Type : constant Entity_Id := Etype (Allocator); New_Allocator : Node_Id; Return_Obj_Access : Entity_Id; begin -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Func_Call, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Func_Call := Expression (Func_Call); end if; -- If the call has already been processed to add build-in-place actuals -- then return. This should not normally occur in an allocator context, -- but we add the protection as a defensive measure. if Is_Expanded_Build_In_Place_Call (Func_Call) then return; end if; -- Mark the call as processed as a build-in-place call Set_Is_Expanded_Build_In_Place_Call (Func_Call); Loc := Sloc (Function_Call); if Is_Entity_Name (Name (Func_Call)) then Function_Id := Entity (Name (Func_Call)); elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then Function_Id := Etype (Name (Func_Call)); else raise Program_Error; end if; Result_Subt := Etype (Function_Id); -- When the result subtype is constrained, the return object must be -- allocated on the caller side, and access to it is passed to the -- function. -- Here and in related routines, we must examine the full view of the -- type, because the view at the point of call may differ from that -- that in the function body, and the expansion mechanism depends on -- the characteristics of the full view. if Is_Constrained (Underlying_Type (Result_Subt)) then -- Replace the initialized allocator of form "new T'(Func (...))" -- with an uninitialized allocator of form "new T", where T is the -- result subtype of the called function. The call to the function -- is handled separately further below. New_Allocator := Make_Allocator (Loc, Expression => New_Reference_To (Result_Subt, Loc)); Set_No_Initialization (New_Allocator); -- Copy attributes to new allocator. Note that the new allocator -- logically comes from source if the original one did, so copy the -- relevant flag. This ensures proper treatment of the restriction -- No_Implicit_Heap_Allocations in this case. Set_Storage_Pool (New_Allocator, Storage_Pool (Allocator)); Set_Procedure_To_Call (New_Allocator, Procedure_To_Call (Allocator)); Set_Comes_From_Source (New_Allocator, Comes_From_Source (Allocator)); Rewrite (Allocator, New_Allocator); -- Create a new access object and initialize it to the result of the -- new uninitialized allocator. Return_Obj_Access := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); Set_Etype (Return_Obj_Access, Acc_Type); Insert_Action (Allocator, Make_Object_Declaration (Loc, Defining_Identifier => Return_Obj_Access, Object_Definition => New_Reference_To (Acc_Type, Loc), Expression => Relocate_Node (Allocator))); -- When the function has a controlling result, an allocation-form -- parameter must be passed indicating that the caller is allocating -- the result object. This is needed because such a function can be -- called as a dispatching operation and must be treated similarly -- to functions with unconstrained result subtypes. Add_Alloc_Form_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); Add_Final_List_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Acc_Type); Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type)); -- Add an implicit actual to the function call that provides access -- to the allocated object. An unchecked conversion to the (specific) -- result subtype of the function is inserted to handle cases where -- the access type of the allocator has a class-wide designated type. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Reference_To (Result_Subt, Loc), Expression => Make_Explicit_Dereference (Loc, Prefix => New_Reference_To (Return_Obj_Access, Loc)))); -- When the result subtype is unconstrained, the function itself must -- perform the allocation of the return object, so we pass parameters -- indicating that. We don't yet handle the case where the allocation -- must be done in a user-defined storage pool, which will require -- passing another actual or two to provide allocation/deallocation -- operations. ??? else -- Pass an allocation parameter indicating that the function should -- allocate its result on the heap. Add_Alloc_Form_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Global_Heap); Add_Final_List_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Acc_Type); Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type)); -- The caller does not provide the return object in this case, so we -- have to pass null for the object access actual. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Return_Object => Empty); end if; -- Finally, replace the allocator node with a reference to the result -- of the function call itself (which will effectively be an access -- to the object created by the allocator). Rewrite (Allocator, Make_Reference (Loc, Relocate_Node (Function_Call))); Analyze_And_Resolve (Allocator, Acc_Type); end Make_Build_In_Place_Call_In_Allocator; --------------------------------------------------- -- Make_Build_In_Place_Call_In_Anonymous_Context -- --------------------------------------------------- procedure Make_Build_In_Place_Call_In_Anonymous_Context (Function_Call : Node_Id) is Loc : Source_Ptr; Func_Call : Node_Id := Function_Call; Function_Id : Entity_Id; Result_Subt : Entity_Id; Return_Obj_Id : Entity_Id; Return_Obj_Decl : Entity_Id; begin -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Func_Call, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Func_Call := Expression (Func_Call); end if; -- If the call has already been processed to add build-in-place actuals -- then return. One place this can occur is for calls to build-in-place -- functions that occur within a call to a protected operation, where -- due to rewriting and expansion of the protected call there can be -- more than one call to Expand_Actuals for the same set of actuals. if Is_Expanded_Build_In_Place_Call (Func_Call) then return; end if; -- Mark the call as processed as a build-in-place call Set_Is_Expanded_Build_In_Place_Call (Func_Call); Loc := Sloc (Function_Call); if Is_Entity_Name (Name (Func_Call)) then Function_Id := Entity (Name (Func_Call)); elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then Function_Id := Etype (Name (Func_Call)); else raise Program_Error; end if; Result_Subt := Etype (Function_Id); -- When the result subtype is constrained, an object of the subtype is -- declared and an access value designating it is passed as an actual. if Is_Constrained (Underlying_Type (Result_Subt)) then -- Create a temporary object to hold the function result Return_Obj_Id := Make_Defining_Identifier (Loc, Chars => New_Internal_Name ('R')); Set_Etype (Return_Obj_Id, Result_Subt); Return_Obj_Decl := Make_Object_Declaration (Loc, Defining_Identifier => Return_Obj_Id, Aliased_Present => True, Object_Definition => New_Reference_To (Result_Subt, Loc)); Set_No_Initialization (Return_Obj_Decl); Insert_Action (Func_Call, Return_Obj_Decl); -- When the function has a controlling result, an allocation-form -- parameter must be passed indicating that the caller is allocating -- the result object. This is needed because such a function can be -- called as a dispatching operation and must be treated similarly -- to functions with unconstrained result subtypes. Add_Alloc_Form_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); Add_Final_List_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Acc_Type => Empty); Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); -- Add an implicit actual to the function call that provides access -- to the caller's return object. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, New_Reference_To (Return_Obj_Id, Loc)); -- When the result subtype is unconstrained, the function must allocate -- the return object in the secondary stack, so appropriate implicit -- parameters are added to the call to indicate that. A transient -- scope is established to ensure eventual cleanup of the result. else -- Pass an allocation parameter indicating that the function should -- allocate its result on the secondary stack. Add_Alloc_Form_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Secondary_Stack); Add_Final_List_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Acc_Type => Empty); Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); -- Pass a null value to the function since no return object is -- available on the caller side. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Empty); Establish_Transient_Scope (Func_Call, Sec_Stack => True); end if; end Make_Build_In_Place_Call_In_Anonymous_Context; -------------------------------------------- -- Make_Build_In_Place_Call_In_Assignment -- -------------------------------------------- procedure Make_Build_In_Place_Call_In_Assignment (Assign : Node_Id; Function_Call : Node_Id) is Lhs : constant Node_Id := Name (Assign); Func_Call : Node_Id := Function_Call; Func_Id : Entity_Id; Loc : Source_Ptr; Obj_Decl : Node_Id; Obj_Id : Entity_Id; Ptr_Typ : Entity_Id; Ptr_Typ_Decl : Node_Id; Result_Subt : Entity_Id; Target : Node_Id; begin -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Func_Call, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Func_Call := Expression (Func_Call); end if; -- If the call has already been processed to add build-in-place actuals -- then return. This should not normally occur in an assignment context, -- but we add the protection as a defensive measure. if Is_Expanded_Build_In_Place_Call (Func_Call) then return; end if; -- Mark the call as processed as a build-in-place call Set_Is_Expanded_Build_In_Place_Call (Func_Call); Loc := Sloc (Function_Call); if Is_Entity_Name (Name (Func_Call)) then Func_Id := Entity (Name (Func_Call)); elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then Func_Id := Etype (Name (Func_Call)); else raise Program_Error; end if; Result_Subt := Etype (Func_Id); -- When the result subtype is unconstrained, an additional actual must -- be passed to indicate that the caller is providing the return object. -- This parameter must also be passed when the called function has a -- controlling result, because dispatching calls to the function needs -- to be treated effectively the same as calls to class-wide functions. Add_Alloc_Form_Actual_To_Build_In_Place_Call (Func_Call, Func_Id, Alloc_Form => Caller_Allocation); -- If Lhs is a selected component, then pass it along so that its prefix -- object will be used as the source of the finalization list. if Nkind (Lhs) = N_Selected_Component then Add_Final_List_Actual_To_Build_In_Place_Call (Func_Call, Func_Id, Acc_Type => Empty, Sel_Comp => Lhs); else Add_Final_List_Actual_To_Build_In_Place_Call (Func_Call, Func_Id, Acc_Type => Empty); end if; Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Func_Id, Make_Identifier (Loc, Name_uMaster)); -- Add an implicit actual to the function call that provides access to -- the caller's return object. Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Func_Id, Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Reference_To (Result_Subt, Loc), Expression => Relocate_Node (Lhs))); -- Create an access type designating the function's result subtype Ptr_Typ := Make_Defining_Identifier (Loc, New_Internal_Name ('A')); Ptr_Typ_Decl := Make_Full_Type_Declaration (Loc, Defining_Identifier => Ptr_Typ, Type_Definition => Make_Access_To_Object_Definition (Loc, All_Present => True, Subtype_Indication => New_Reference_To (Result_Subt, Loc))); Insert_After_And_Analyze (Assign, Ptr_Typ_Decl); -- Finally, create an access object initialized to a reference to the -- function call. Obj_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); Set_Etype (Obj_Id, Ptr_Typ); Obj_Decl := Make_Object_Declaration (Loc, Defining_Identifier => Obj_Id, Object_Definition => New_Reference_To (Ptr_Typ, Loc), Expression => Make_Reference (Loc, Prefix => Relocate_Node (Func_Call))); Insert_After_And_Analyze (Ptr_Typ_Decl, Obj_Decl); Rewrite (Assign, Make_Null_Statement (Loc)); -- Retrieve the target of the assignment if Nkind (Lhs) = N_Selected_Component then Target := Selector_Name (Lhs); elsif Nkind (Lhs) = N_Type_Conversion then Target := Expression (Lhs); else Target := Lhs; end if; -- If we are assigning to a return object or this is an expression of -- an extension aggregate, the target should either be an identifier -- or a simple expression. All other cases imply a different scenario. if Nkind (Target) in N_Has_Entity then Target := Entity (Target); else return; end if; -- When the target of the assignment is a return object of an enclosing -- build-in-place function and also requires finalization, the list -- generated for the assignment must be moved to that of the enclosing -- function. -- function Enclosing_BIP_Function return Ctrl_Typ is -- begin -- return (Ctrl_Parent_Part => BIP_Function with ...); -- end Enclosing_BIP_Function; if Is_Return_Object (Target) and then Needs_Finalization (Etype (Target)) and then Needs_Finalization (Result_Subt) then declare Obj_List : constant Node_Id := Find_Final_List (Obj_Id); Encl_List : Node_Id; Encl_Scop : Entity_Id; begin Encl_Scop := Scope (Target); -- Locate the scope of the extended return statement while Present (Encl_Scop) and then Ekind (Encl_Scop) /= E_Return_Statement loop Encl_Scop := Scope (Encl_Scop); end loop; -- A return object should always be enclosed by a return statement -- scope at some level. pragma Assert (Present (Encl_Scop)); Encl_List := Make_Attribute_Reference (Loc, Prefix => New_Reference_To ( Finalization_Chain_Entity (Encl_Scop), Loc), Attribute_Name => Name_Unrestricted_Access); -- Generate a call to move final list Insert_After_And_Analyze (Obj_Decl, Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (RTE (RE_Move_Final_List), Loc), Parameter_Associations => New_List (Obj_List, Encl_List))); end; end if; end Make_Build_In_Place_Call_In_Assignment; ---------------------------------------------------- -- Make_Build_In_Place_Call_In_Object_Declaration -- ---------------------------------------------------- procedure Make_Build_In_Place_Call_In_Object_Declaration (Object_Decl : Node_Id; Function_Call : Node_Id) is Loc : Source_Ptr; Obj_Def_Id : constant Entity_Id := Defining_Identifier (Object_Decl); Func_Call : Node_Id := Function_Call; Function_Id : Entity_Id; Result_Subt : Entity_Id; Caller_Object : Node_Id; Call_Deref : Node_Id; Ref_Type : Entity_Id; Ptr_Typ_Decl : Node_Id; Def_Id : Entity_Id; New_Expr : Node_Id; Enclosing_Func : Entity_Id; Pass_Caller_Acc : Boolean := False; begin -- Step past qualification or unchecked conversion (the latter can occur -- in cases of calls to 'Input). if Nkind_In (Func_Call, N_Qualified_Expression, N_Unchecked_Type_Conversion) then Func_Call := Expression (Func_Call); end if; -- If the call has already been processed to add build-in-place actuals -- then return. This should not normally occur in an object declaration, -- but we add the protection as a defensive measure. if Is_Expanded_Build_In_Place_Call (Func_Call) then return; end if; -- Mark the call as processed as a build-in-place call Set_Is_Expanded_Build_In_Place_Call (Func_Call); Loc := Sloc (Function_Call); if Is_Entity_Name (Name (Func_Call)) then Function_Id := Entity (Name (Func_Call)); elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then Function_Id := Etype (Name (Func_Call)); else raise Program_Error; end if; Result_Subt := Etype (Function_Id); -- In the constrained case, add an implicit actual to the function call -- that provides access to the declared object. An unchecked conversion -- to the (specific) result type of the function is inserted to handle -- the case where the object is declared with a class-wide type. if Is_Constrained (Underlying_Type (Result_Subt)) then Caller_Object := Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Reference_To (Result_Subt, Loc), Expression => New_Reference_To (Obj_Def_Id, Loc)); -- When the function has a controlling result, an allocation-form -- parameter must be passed indicating that the caller is allocating -- the result object. This is needed because such a function can be -- called as a dispatching operation and must be treated similarly -- to functions with unconstrained result subtypes. Add_Alloc_Form_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); -- If the function's result subtype is unconstrained and the object is -- a return object of an enclosing build-in-place function, then the -- implicit build-in-place parameters of the enclosing function must be -- passed along to the called function. (Unfortunately, this won't cover -- the case of extension aggregates where the ancestor part is a build- -- in-place unconstrained function call that should be passed along the -- caller's parameters. Currently those get mishandled by reassigning -- the result of the call to the aggregate return object, when the call -- result should really be directly built in place in the aggregate and -- not built in a temporary. ???) elsif Is_Return_Object (Defining_Identifier (Object_Decl)) then Pass_Caller_Acc := True; Enclosing_Func := Enclosing_Subprogram (Obj_Def_Id); -- If the enclosing function has a constrained result type, then -- caller allocation will be used. if Is_Constrained (Etype (Enclosing_Func)) then Add_Alloc_Form_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); -- Otherwise, when the enclosing function has an unconstrained result -- type, the BIP_Alloc_Form formal of the enclosing function must be -- passed along to the callee. else Add_Alloc_Form_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form_Exp => New_Reference_To (Build_In_Place_Formal (Enclosing_Func, BIP_Alloc_Form), Loc)); end if; -- Retrieve the BIPacc formal from the enclosing function and convert -- it to the access type of the callee's BIP_Object_Access formal. Caller_Object := Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Reference_To (Etype (Build_In_Place_Formal (Function_Id, BIP_Object_Access)), Loc), Expression => New_Reference_To (Build_In_Place_Formal (Enclosing_Func, BIP_Object_Access), Loc)); -- In other unconstrained cases, pass an indication to do the allocation -- on the secondary stack and set Caller_Object to Empty so that a null -- value will be passed for the caller's object address. A transient -- scope is established to ensure eventual cleanup of the result. else Add_Alloc_Form_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Alloc_Form => Secondary_Stack); Caller_Object := Empty; Establish_Transient_Scope (Object_Decl, Sec_Stack => True); end if; Add_Final_List_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Acc_Type => Empty); if Nkind (Parent (Object_Decl)) = N_Extended_Return_Statement and then Has_Task (Result_Subt) then Enclosing_Func := Enclosing_Subprogram (Obj_Def_Id); -- Here we're passing along the master that was passed in to this -- function. Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Master_Actual => New_Reference_To (Build_In_Place_Formal (Enclosing_Func, BIP_Master), Loc)); else Add_Task_Actuals_To_Build_In_Place_Call (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); end if; Add_Access_Actual_To_Build_In_Place_Call (Func_Call, Function_Id, Caller_Object, Is_Access => Pass_Caller_Acc); -- Create an access type designating the function's result subtype Ref_Type := Make_Defining_Identifier (Loc, New_Internal_Name ('A')); Ptr_Typ_Decl := Make_Full_Type_Declaration (Loc, Defining_Identifier => Ref_Type, Type_Definition => Make_Access_To_Object_Definition (Loc, All_Present => True, Subtype_Indication => New_Reference_To (Result_Subt, Loc))); -- The access type and its accompanying object must be inserted after -- the object declaration in the constrained case, so that the function -- call can be passed access to the object. In the unconstrained case, -- the access type and object must be inserted before the object, since -- the object declaration is rewritten to be a renaming of a dereference -- of the access object. if Is_Constrained (Underlying_Type (Result_Subt)) then Insert_After_And_Analyze (Object_Decl, Ptr_Typ_Decl); else Insert_Action (Object_Decl, Ptr_Typ_Decl); end if; -- Finally, create an access object initialized to a reference to the -- function call. Def_Id := Make_Defining_Identifier (Loc, Chars => New_Internal_Name ('R')); Set_Etype (Def_Id, Ref_Type); New_Expr := Make_Reference (Loc, Prefix => Relocate_Node (Func_Call)); Insert_After_And_Analyze (Ptr_Typ_Decl, Make_Object_Declaration (Loc, Defining_Identifier => Def_Id, Object_Definition => New_Reference_To (Ref_Type, Loc), Expression => New_Expr)); if Is_Constrained (Underlying_Type (Result_Subt)) then Set_Expression (Object_Decl, Empty); Set_No_Initialization (Object_Decl); -- In case of an unconstrained result subtype, rewrite the object -- declaration as an object renaming where the renamed object is a -- dereference of <function_Call>'reference: -- -- Obj : Subt renames <function_call>'Ref.all; else Call_Deref := Make_Explicit_Dereference (Loc, Prefix => New_Reference_To (Def_Id, Loc)); Rewrite (Object_Decl, Make_Object_Renaming_Declaration (Loc, Defining_Identifier => Make_Defining_Identifier (Loc, New_Internal_Name ('D')), Access_Definition => Empty, Subtype_Mark => New_Occurrence_Of (Result_Subt, Loc), Name => Call_Deref)); Set_Renamed_Object (Defining_Identifier (Object_Decl), Call_Deref); Analyze (Object_Decl); -- Replace the internal identifier of the renaming declaration's -- entity with identifier of the original object entity. We also have -- to exchange the entities containing their defining identifiers to -- ensure the correct replacement of the object declaration by the -- object renaming declaration to avoid homograph conflicts (since -- the object declaration's defining identifier was already entered -- in current scope). The Next_Entity links of the two entities also -- have to be swapped since the entities are part of the return -- scope's entity list and the list structure would otherwise be -- corrupted. Finally, the homonym chain must be preserved as well. declare Renaming_Def_Id : constant Entity_Id := Defining_Identifier (Object_Decl); Next_Entity_Temp : constant Entity_Id := Next_Entity (Renaming_Def_Id); begin Set_Chars (Renaming_Def_Id, Chars (Obj_Def_Id)); -- Swap next entity links in preparation for exchanging entities Set_Next_Entity (Renaming_Def_Id, Next_Entity (Obj_Def_Id)); Set_Next_Entity (Obj_Def_Id, Next_Entity_Temp); Set_Homonym (Renaming_Def_Id, Homonym (Obj_Def_Id)); Exchange_Entities (Renaming_Def_Id, Obj_Def_Id); end; end if; -- If the object entity has a class-wide Etype, then we need to change -- it to the result subtype of the function call, because otherwise the -- object will be class-wide without an explicit initialization and -- won't be allocated properly by the back end. It seems unclean to make -- such a revision to the type at this point, and we should try to -- improve this treatment when build-in-place functions with class-wide -- results are implemented. ??? if Is_Class_Wide_Type (Etype (Defining_Identifier (Object_Decl))) then Set_Etype (Defining_Identifier (Object_Decl), Result_Subt); end if; end Make_Build_In_Place_Call_In_Object_Declaration; -------------------------- -- Needs_BIP_Final_List -- -------------------------- function Needs_BIP_Final_List (E : Entity_Id) return Boolean is pragma Assert (Is_Build_In_Place_Function (E)); Result_Subt : constant Entity_Id := Underlying_Type (Etype (E)); begin -- We need the BIP_Final_List if the result type needs finalization. We -- also need it for tagged types, even if not class-wide, because some -- type extension might need finalization, and all overriding functions -- must have the same calling conventions. However, if there is a -- pragma Restrictions (No_Finalization), we never need this parameter. return (Needs_Finalization (Result_Subt) or else Is_Tagged_Type (Underlying_Type (Result_Subt))) and then not Restriction_Active (No_Finalization); end Needs_BIP_Final_List; end Exp_Ch6;
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