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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- E X P _ I N T R -- -- -- -- 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 Einfo; use Einfo; with Elists; use Elists; with Errout; use Errout; with Exp_Atag; use Exp_Atag; with Exp_Ch4; use Exp_Ch4; with Exp_Ch7; use Exp_Ch7; with Exp_Ch11; use Exp_Ch11; with Exp_Code; use Exp_Code; with Exp_Fixd; use Exp_Fixd; with Exp_Util; use Exp_Util; with Freeze; use Freeze; with Namet; use Namet; with Nmake; use Nmake; with Nlists; use Nlists; with Opt; use Opt; with Restrict; use Restrict; with Rident; use Rident; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Eval; use Sem_Eval; with Sem_Res; use Sem_Res; with Sem_Type; use Sem_Type; with Sem_Util; use Sem_Util; with Sinfo; use Sinfo; with Sinput; use Sinput; with Snames; use Snames; with Stand; use Stand; with Stringt; use Stringt; with Tbuild; use Tbuild; with Uintp; use Uintp; with Urealp; use Urealp; package body Exp_Intr is ----------------------- -- Local Subprograms -- ----------------------- procedure Expand_Is_Negative (N : Node_Id); -- Expand a call to the intrinsic Is_Negative function procedure Expand_Dispatching_Constructor_Call (N : Node_Id); -- Expand a call to an instantiation of Generic_Dispatching_Constructor -- into a dispatching call to the actual subprogram associated with the -- Constructor formal subprogram, passing it the Parameters actual of -- the call to the instantiation and dispatching based on call's Tag -- parameter. procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id); -- Expand a call to Exception_Information/Message/Name. The first -- parameter, N, is the node for the function call, and Ent is the -- entity for the corresponding routine in the Ada.Exceptions package. procedure Expand_Import_Call (N : Node_Id); -- Expand a call to Import_Address/Longest_Integer/Value. The parameter -- N is the node for the function call. procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind); -- Expand an intrinsic shift operation, N and E are from the call to -- Expand_Intrinsic_Call (call node and subprogram spec entity) and -- K is the kind for the shift node procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id); -- Expand a call to an instantiation of Unchecked_Conversion into a node -- N_Unchecked_Type_Conversion. procedure Expand_Unc_Deallocation (N : Node_Id); -- Expand a call to an instantiation of Unchecked_Deallocation into a node -- N_Free_Statement and appropriate context. procedure Expand_To_Address (N : Node_Id); procedure Expand_To_Pointer (N : Node_Id); -- Expand a call to corresponding function, declared in an instance of -- System.Address_To_Access_Conversions. procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id); -- Rewrite the node by the appropriate string or positive constant. -- Nam can be one of the following: -- Name_File - expand string that is the name of source file -- Name_Line - expand integer line number -- Name_Source_Location - expand string of form file:line -- Name_Enclosing_Entity - expand string with name of enclosing entity ----------------------------------------- -- Expand_Dispatching_Constructor_Call -- ----------------------------------------- -- Transform a call to an instantiation of Generic_Dispatching_Constructor -- of the form: -- GDC_Instance (The_Tag, Parameters'Access) -- to a class-wide conversion of a dispatching call to the actual -- associated with the formal subprogram Construct, designating The_Tag -- as the controlling tag of the call: -- T'Class (Construct'Actual (Params)) -- Controlling tag is The_Tag -- which will eventually be expanded to the following: -- T'Class (The_Tag.all (Construct'Actual'Index).all (Params)) -- A class-wide membership test is also generated, preceding the call, to -- ensure that the controlling tag denotes a type in T'Class. procedure Expand_Dispatching_Constructor_Call (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Tag_Arg : constant Node_Id := First_Actual (N); Param_Arg : constant Node_Id := Next_Actual (Tag_Arg); Subp_Decl : constant Node_Id := Parent (Parent (Entity (Name (N)))); Inst_Pkg : constant Node_Id := Parent (Subp_Decl); Act_Rename : Node_Id; Act_Constr : Entity_Id; Iface_Tag : Node_Id := Empty; Cnstr_Call : Node_Id; Result_Typ : Entity_Id; begin -- The subprogram is the third actual in the instantiation, and is -- retrieved from the corresponding renaming declaration. However, -- freeze nodes may appear before, so we retrieve the declaration -- with an explicit loop. Act_Rename := First (Visible_Declarations (Inst_Pkg)); while Nkind (Act_Rename) /= N_Subprogram_Renaming_Declaration loop Next (Act_Rename); end loop; Act_Constr := Entity (Name (Act_Rename)); Result_Typ := Class_Wide_Type (Etype (Act_Constr)); -- Ada 2005 (AI-251): If the result is an interface type, the function -- returns a class-wide interface type (otherwise the resulting object -- would be abstract!) if Is_Interface (Etype (Act_Constr)) then Set_Etype (Act_Constr, Result_Typ); -- If the result type is not parent of Tag_Arg then we need to -- locate the tag of the secondary dispatch table. if not Is_Ancestor (Etype (Result_Typ), Etype (Tag_Arg)) then pragma Assert (not Is_Interface (Etype (Tag_Arg))); Iface_Tag := Make_Object_Declaration (Loc, Defining_Identifier => Make_Defining_Identifier (Loc, New_Internal_Name ('V')), Object_Definition => New_Reference_To (RTE (RE_Tag), Loc), Expression => Make_Function_Call (Loc, Name => New_Reference_To (RTE (RE_Secondary_Tag), Loc), Parameter_Associations => New_List ( Relocate_Node (Tag_Arg), New_Reference_To (Node (First_Elmt (Access_Disp_Table (Etype (Etype (Act_Constr))))), Loc)))); Insert_Action (N, Iface_Tag); end if; end if; -- Create the call to the actual Constructor function Cnstr_Call := Make_Function_Call (Loc, Name => New_Occurrence_Of (Act_Constr, Loc), Parameter_Associations => New_List (Relocate_Node (Param_Arg))); -- Establish its controlling tag from the tag passed to the instance -- The tag may be given by a function call, in which case a temporary -- should be generated now, to prevent out-of-order insertions during -- the expansion of that call when stack-checking is enabled. if Present (Iface_Tag) then Set_Controlling_Argument (Cnstr_Call, New_Occurrence_Of (Defining_Identifier (Iface_Tag), Loc)); else Remove_Side_Effects (Tag_Arg); Set_Controlling_Argument (Cnstr_Call, Relocate_Node (Tag_Arg)); end if; -- Rewrite and analyze the call to the instance as a class-wide -- conversion of the call to the actual constructor. Rewrite (N, Convert_To (Result_Typ, Cnstr_Call)); Analyze_And_Resolve (N, Etype (Act_Constr)); -- Do not generate a run-time check on the built object if tag -- checks are suppressed for the result type or VM_Target /= No_VM if Tag_Checks_Suppressed (Etype (Result_Typ)) or else not Tagged_Type_Expansion then null; -- Generate a class-wide membership test to ensure that the call's tag -- argument denotes a type within the class. We must keep separate the -- case in which the Result_Type of the constructor function is a tagged -- type from the case in which it is an abstract interface because the -- run-time subprogram required to check these cases differ (and have -- one difference in their parameters profile). -- Call CW_Membership if the Result_Type is a tagged type to look for -- the tag in the table of ancestor tags. elsif not Is_Interface (Result_Typ) then declare Obj_Tag_Node : Node_Id := Duplicate_Subexpr (Tag_Arg); CW_Test_Node : Node_Id; begin Build_CW_Membership (Loc, Obj_Tag_Node => Obj_Tag_Node, Typ_Tag_Node => New_Reference_To ( Node (First_Elmt (Access_Disp_Table ( Root_Type (Result_Typ)))), Loc), Related_Nod => N, New_Node => CW_Test_Node); Insert_Action (N, Make_Implicit_If_Statement (N, Condition => Make_Op_Not (Loc, CW_Test_Node), Then_Statements => New_List (Make_Raise_Statement (Loc, New_Occurrence_Of (RTE (RE_Tag_Error), Loc))))); end; -- Call IW_Membership test if the Result_Type is an abstract interface -- to look for the tag in the table of interface tags. else Insert_Action (N, Make_Implicit_If_Statement (N, Condition => Make_Op_Not (Loc, Make_Function_Call (Loc, Name => New_Occurrence_Of (RTE (RE_IW_Membership), Loc), Parameter_Associations => New_List ( Make_Attribute_Reference (Loc, Prefix => Duplicate_Subexpr (Tag_Arg), Attribute_Name => Name_Address), New_Reference_To ( Node (First_Elmt (Access_Disp_Table ( Root_Type (Result_Typ)))), Loc)))), Then_Statements => New_List ( Make_Raise_Statement (Loc, Name => New_Occurrence_Of (RTE (RE_Tag_Error), Loc))))); end if; end Expand_Dispatching_Constructor_Call; --------------------------- -- Expand_Exception_Call -- --------------------------- -- If the function call is not within an exception handler, then the call -- is replaced by a null string. Otherwise the appropriate routine in -- Ada.Exceptions is called passing the choice parameter specification -- from the enclosing handler. If the enclosing handler lacks a choice -- parameter, then one is supplied. procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id) is Loc : constant Source_Ptr := Sloc (N); P : Node_Id; E : Entity_Id; begin -- Climb up parents to see if we are in exception handler P := Parent (N); loop -- Case of not in exception handler, replace by null string if No (P) then Rewrite (N, Make_String_Literal (Loc, Strval => "")); exit; -- Case of in exception handler elsif Nkind (P) = N_Exception_Handler then -- Handler cannot be used for a local raise, and furthermore, this -- is a violation of the No_Exception_Propagation restriction. Set_Local_Raise_Not_OK (P); Check_Restriction (No_Exception_Propagation, N); -- If no choice parameter present, then put one there. Note that -- we do not need to put it on the entity chain, since no one will -- be referencing it by normal visibility methods. if No (Choice_Parameter (P)) then E := Make_Defining_Identifier (Loc, New_Internal_Name ('E')); Set_Choice_Parameter (P, E); Set_Ekind (E, E_Variable); Set_Etype (E, RTE (RE_Exception_Occurrence)); Set_Scope (E, Current_Scope); end if; Rewrite (N, Make_Function_Call (Loc, Name => New_Occurrence_Of (RTE (Ent), Loc), Parameter_Associations => New_List ( New_Occurrence_Of (Choice_Parameter (P), Loc)))); exit; -- Keep climbing! else P := Parent (P); end if; end loop; Analyze_And_Resolve (N, Standard_String); end Expand_Exception_Call; ------------------------ -- Expand_Import_Call -- ------------------------ -- The function call must have a static string as its argument. We create -- a dummy variable which uses this string as the external name in an -- Import pragma. The result is then obtained as the address of this -- dummy variable, converted to the appropriate target type. procedure Expand_Import_Call (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Ent : constant Entity_Id := Entity (Name (N)); Str : constant Node_Id := First_Actual (N); Dum : Entity_Id; begin Dum := Make_Defining_Identifier (Loc, New_Internal_Name ('D')); Insert_Actions (N, New_List ( Make_Object_Declaration (Loc, Defining_Identifier => Dum, Object_Definition => New_Occurrence_Of (Standard_Character, Loc)), Make_Pragma (Loc, Chars => Name_Import, Pragma_Argument_Associations => New_List ( Make_Pragma_Argument_Association (Loc, Expression => Make_Identifier (Loc, Name_Ada)), Make_Pragma_Argument_Association (Loc, Expression => Make_Identifier (Loc, Chars (Dum))), Make_Pragma_Argument_Association (Loc, Chars => Name_Link_Name, Expression => Relocate_Node (Str)))))); Rewrite (N, Unchecked_Convert_To (Etype (Ent), Make_Attribute_Reference (Loc, Prefix => Make_Identifier (Loc, Chars (Dum)), Attribute_Name => Name_Address))); Analyze_And_Resolve (N, Etype (Ent)); end Expand_Import_Call; --------------------------- -- Expand_Intrinsic_Call -- --------------------------- procedure Expand_Intrinsic_Call (N : Node_Id; E : Entity_Id) is Nam : Name_Id; begin -- If an external name is specified for the intrinsic, it is handled -- by the back-end: leave the call node unchanged for now. if Present (Interface_Name (E)) then return; end if; -- If the intrinsic subprogram is generic, gets its original name if Present (Parent (E)) and then Present (Generic_Parent (Parent (E))) then Nam := Chars (Generic_Parent (Parent (E))); else Nam := Chars (E); end if; if Nam = Name_Asm then Expand_Asm_Call (N); elsif Nam = Name_Divide then Expand_Decimal_Divide_Call (N); elsif Nam = Name_Exception_Information then Expand_Exception_Call (N, RE_Exception_Information); elsif Nam = Name_Exception_Message then Expand_Exception_Call (N, RE_Exception_Message); elsif Nam = Name_Exception_Name then Expand_Exception_Call (N, RE_Exception_Name_Simple); elsif Nam = Name_Generic_Dispatching_Constructor then Expand_Dispatching_Constructor_Call (N); elsif Nam = Name_Import_Address or else Nam = Name_Import_Largest_Value or else Nam = Name_Import_Value then Expand_Import_Call (N); elsif Nam = Name_Is_Negative then Expand_Is_Negative (N); elsif Nam = Name_Rotate_Left then Expand_Shift (N, E, N_Op_Rotate_Left); elsif Nam = Name_Rotate_Right then Expand_Shift (N, E, N_Op_Rotate_Right); elsif Nam = Name_Shift_Left then Expand_Shift (N, E, N_Op_Shift_Left); elsif Nam = Name_Shift_Right then Expand_Shift (N, E, N_Op_Shift_Right); elsif Nam = Name_Shift_Right_Arithmetic then Expand_Shift (N, E, N_Op_Shift_Right_Arithmetic); elsif Nam = Name_Unchecked_Conversion then Expand_Unc_Conversion (N, E); elsif Nam = Name_Unchecked_Deallocation then Expand_Unc_Deallocation (N); elsif Nam = Name_To_Address then Expand_To_Address (N); elsif Nam = Name_To_Pointer then Expand_To_Pointer (N); elsif Nam = Name_File or else Nam = Name_Line or else Nam = Name_Source_Location or else Nam = Name_Enclosing_Entity then Expand_Source_Info (N, Nam); -- If we have a renaming, expand the call to the original operation, -- which must itself be intrinsic, since renaming requires matching -- conventions and this has already been checked. elsif Present (Alias (E)) then Expand_Intrinsic_Call (N, Alias (E)); -- The only other case is where an external name was specified, -- since this is the only way that an otherwise unrecognized -- name could escape the checking in Sem_Prag. Nothing needs -- to be done in such a case, since we pass such a call to the -- back end unchanged. else null; end if; end Expand_Intrinsic_Call; ------------------------ -- Expand_Is_Negative -- ------------------------ procedure Expand_Is_Negative (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Opnd : constant Node_Id := Relocate_Node (First_Actual (N)); begin -- We replace the function call by the following expression -- if Opnd < 0.0 then -- True -- else -- if Opnd > 0.0 then -- False; -- else -- Float_Unsigned!(Float (Opnd)) /= 0 -- end if; -- end if; Rewrite (N, Make_Conditional_Expression (Loc, Expressions => New_List ( Make_Op_Lt (Loc, Left_Opnd => Duplicate_Subexpr (Opnd), Right_Opnd => Make_Real_Literal (Loc, Ureal_0)), New_Occurrence_Of (Standard_True, Loc), Make_Conditional_Expression (Loc, Expressions => New_List ( Make_Op_Gt (Loc, Left_Opnd => Duplicate_Subexpr_No_Checks (Opnd), Right_Opnd => Make_Real_Literal (Loc, Ureal_0)), New_Occurrence_Of (Standard_False, Loc), Make_Op_Ne (Loc, Left_Opnd => Unchecked_Convert_To (RTE (RE_Float_Unsigned), Convert_To (Standard_Float, Duplicate_Subexpr_No_Checks (Opnd))), Right_Opnd => Make_Integer_Literal (Loc, 0))))))); Analyze_And_Resolve (N, Standard_Boolean); end Expand_Is_Negative; ------------------ -- Expand_Shift -- ------------------ -- This procedure is used to convert a call to a shift function to the -- corresponding operator node. This conversion is not done by the usual -- circuit for converting calls to operator functions (e.g. "+"(1,2)) to -- operator nodes, because shifts are not predefined operators. -- As a result, whenever a shift is used in the source program, it will -- remain as a call until converted by this routine to the operator node -- form which Gigi is expecting to see. -- Note: it is possible for the expander to generate shift operator nodes -- directly, which will be analyzed in the normal manner by calling Analyze -- and Resolve. Such shift operator nodes will not be seen by Expand_Shift. procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind) is Loc : constant Source_Ptr := Sloc (N); Typ : constant Entity_Id := Etype (N); Left : constant Node_Id := First_Actual (N); Right : constant Node_Id := Next_Actual (Left); Ltyp : constant Node_Id := Etype (Left); Rtyp : constant Node_Id := Etype (Right); Snode : Node_Id; begin Snode := New_Node (K, Loc); Set_Left_Opnd (Snode, Relocate_Node (Left)); Set_Right_Opnd (Snode, Relocate_Node (Right)); Set_Chars (Snode, Chars (E)); Set_Etype (Snode, Base_Type (Typ)); Set_Entity (Snode, E); if Compile_Time_Known_Value (Type_High_Bound (Rtyp)) and then Expr_Value (Type_High_Bound (Rtyp)) < Esize (Ltyp) then Set_Shift_Count_OK (Snode, True); end if; -- Do the rewrite. Note that we don't call Analyze and Resolve on -- this node, because it already got analyzed and resolved when -- it was a function call! Rewrite (N, Snode); Set_Analyzed (N); end Expand_Shift; ------------------------ -- Expand_Source_Info -- ------------------------ procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id) is Loc : constant Source_Ptr := Sloc (N); Ent : Entity_Id; procedure Write_Entity_Name (E : Entity_Id); -- Recursive procedure to construct string for qualified name of -- enclosing program unit. The qualification stops at an enclosing -- scope has no source name (block or loop). If entity is a subprogram -- instance, skip enclosing wrapper package. ----------------------- -- Write_Entity_Name -- ----------------------- procedure Write_Entity_Name (E : Entity_Id) is SDef : Source_Ptr; TDef : constant Source_Buffer_Ptr := Source_Text (Get_Source_File_Index (Sloc (E))); begin -- Nothing to do if at outer level if Scope (E) = Standard_Standard then null; -- If scope comes from source, write its name elsif Comes_From_Source (Scope (E)) then Write_Entity_Name (Scope (E)); Add_Char_To_Name_Buffer ('.'); -- If in wrapper package skip past it elsif Is_Wrapper_Package (Scope (E)) then Write_Entity_Name (Scope (Scope (E))); Add_Char_To_Name_Buffer ('.'); -- Otherwise nothing to output (happens in unnamed block statements) else null; end if; -- Loop to output the name -- is this right wrt wide char encodings ??? (no!) SDef := Sloc (E); while TDef (SDef) in '0' .. '9' or else TDef (SDef) >= 'A' or else TDef (SDef) = ASCII.ESC loop Add_Char_To_Name_Buffer (TDef (SDef)); SDef := SDef + 1; end loop; end Write_Entity_Name; -- Start of processing for Expand_Source_Info begin -- Integer cases if Nam = Name_Line then Rewrite (N, Make_Integer_Literal (Loc, Intval => UI_From_Int (Int (Get_Logical_Line_Number (Loc))))); Analyze_And_Resolve (N, Standard_Positive); -- String cases else Name_Len := 0; case Nam is when Name_File => Get_Decoded_Name_String (Reference_Name (Get_Source_File_Index (Loc))); when Name_Source_Location => Build_Location_String (Loc); when Name_Enclosing_Entity => -- Skip enclosing blocks to reach enclosing unit Ent := Current_Scope; while Present (Ent) loop exit when Ekind (Ent) /= E_Block and then Ekind (Ent) /= E_Loop; Ent := Scope (Ent); end loop; -- Ent now points to the relevant defining entity Write_Entity_Name (Ent); when others => raise Program_Error; end case; Rewrite (N, Make_String_Literal (Loc, Strval => String_From_Name_Buffer)); Analyze_And_Resolve (N, Standard_String); end if; Set_Is_Static_Expression (N); end Expand_Source_Info; --------------------------- -- Expand_Unc_Conversion -- --------------------------- procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id) is Func : constant Entity_Id := Entity (Name (N)); Conv : Node_Id; Ftyp : Entity_Id; Ttyp : Entity_Id; begin -- Rewrite as unchecked conversion node. Note that we must convert -- the operand to the formal type of the input parameter of the -- function, so that the resulting N_Unchecked_Type_Conversion -- call indicates the correct types for Gigi. -- Right now, we only do this if a scalar type is involved. It is -- not clear if it is needed in other cases. If we do attempt to -- do the conversion unconditionally, it crashes 3411-018. To be -- investigated further ??? Conv := Relocate_Node (First_Actual (N)); Ftyp := Etype (First_Formal (Func)); if Is_Scalar_Type (Ftyp) then Conv := Convert_To (Ftyp, Conv); Set_Parent (Conv, N); Analyze_And_Resolve (Conv); end if; -- The instantiation of Unchecked_Conversion creates a wrapper package, -- and the target type is declared as a subtype of the actual. Recover -- the actual, which is the subtype indic. in the subtype declaration -- for the target type. This is semantically correct, and avoids -- anomalies with access subtypes. For entities, leave type as is. -- We do the analysis here, because we do not want the compiler -- to try to optimize or otherwise reorganize the unchecked -- conversion node. Ttyp := Etype (E); if Is_Entity_Name (Conv) then null; elsif Nkind (Parent (Ttyp)) = N_Subtype_Declaration then Ttyp := Entity (Subtype_Indication (Parent (Etype (E)))); elsif Is_Itype (Ttyp) then Ttyp := Entity (Subtype_Indication (Associated_Node_For_Itype (Ttyp))); else raise Program_Error; end if; Rewrite (N, Unchecked_Convert_To (Ttyp, Conv)); Set_Etype (N, Ttyp); Set_Analyzed (N); if Nkind (N) = N_Unchecked_Type_Conversion then Expand_N_Unchecked_Type_Conversion (N); end if; end Expand_Unc_Conversion; ----------------------------- -- Expand_Unc_Deallocation -- ----------------------------- -- Generate the following Code : -- if Arg /= null then -- <Finalize_Call> (.., T'Class(Arg.all), ..); -- for controlled types -- Free (Arg); -- Arg := Null; -- end if; -- For a task, we also generate a call to Free_Task to ensure that the -- task itself is freed if it is terminated, ditto for a simple protected -- object, with a call to Finalize_Protection. For composite types that -- have tasks or simple protected objects as components, we traverse the -- structures to find and terminate those components. procedure Expand_Unc_Deallocation (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Arg : constant Node_Id := First_Actual (N); Typ : constant Entity_Id := Etype (Arg); Stmts : constant List_Id := New_List; Rtyp : constant Entity_Id := Underlying_Type (Root_Type (Typ)); Pool : constant Entity_Id := Associated_Storage_Pool (Rtyp); Desig_T : constant Entity_Id := Designated_Type (Typ); Gen_Code : Node_Id; Free_Node : Node_Id; Deref : Node_Id; Free_Arg : Node_Id; Free_Cod : List_Id; Blk : Node_Id; Arg_Known_Non_Null : constant Boolean := Known_Non_Null (N); -- This captures whether we know the argument to be non-null so that -- we can avoid the test. The reason that we need to capture this is -- that we analyze some generated statements before properly attaching -- them to the tree, and that can disturb current value settings. begin if No_Pool_Assigned (Rtyp) then Error_Msg_N ("?deallocation from empty storage pool!", N); end if; -- Nothing to do if we know the argument is null if Known_Null (N) then return; end if; -- Processing for pointer to controlled type if Needs_Finalization (Desig_T) then Deref := Make_Explicit_Dereference (Loc, Prefix => Duplicate_Subexpr_No_Checks (Arg)); -- If the type is tagged, then we must force dispatching on the -- finalization call because the designated type may not be the -- actual type of the object. if Is_Tagged_Type (Desig_T) and then not Is_Class_Wide_Type (Desig_T) then Deref := Unchecked_Convert_To (Class_Wide_Type (Desig_T), Deref); elsif not Is_Tagged_Type (Desig_T) then -- Set type of result, to force a conversion when needed (see -- exp_ch7, Convert_View), given that Deep_Finalize may be -- inherited from the parent type, and we need the type of the -- expression to see whether the conversion is in fact needed. Set_Etype (Deref, Desig_T); end if; Free_Cod := Make_Final_Call (Ref => Deref, Typ => Desig_T, With_Detach => New_Reference_To (Standard_True, Loc)); if Abort_Allowed then Prepend_To (Free_Cod, Build_Runtime_Call (Loc, RE_Abort_Defer)); Blk := Make_Block_Statement (Loc, Handled_Statement_Sequence => Make_Handled_Sequence_Of_Statements (Loc, Statements => Free_Cod, At_End_Proc => New_Occurrence_Of (RTE (RE_Abort_Undefer_Direct), Loc))); -- We now expand the exception (at end) handler. We set a -- temporary parent pointer since we have not attached Blk -- to the tree yet. Set_Parent (Blk, N); Analyze (Blk); Expand_At_End_Handler (Handled_Statement_Sequence (Blk), Entity (Identifier (Blk))); Append (Blk, Stmts); -- We kill saved current values, since analyzing statements not -- properly attached to the tree can set wrong current values. Kill_Current_Values; else Append_List_To (Stmts, Free_Cod); end if; end if; -- For a task type, call Free_Task before freeing the ATCB if Is_Task_Type (Desig_T) then declare Stat : Node_Id := Prev (N); Nam1 : Node_Id; Nam2 : Node_Id; begin -- An Abort followed by a Free will not do what the user -- expects, because the abort is not immediate. This is -- worth a friendly warning. while Present (Stat) and then not Comes_From_Source (Original_Node (Stat)) loop Prev (Stat); end loop; if Present (Stat) and then Nkind (Original_Node (Stat)) = N_Abort_Statement then Stat := Original_Node (Stat); Nam1 := First (Names (Stat)); Nam2 := Original_Node (First (Parameter_Associations (N))); if Nkind (Nam1) = N_Explicit_Dereference and then Is_Entity_Name (Prefix (Nam1)) and then Is_Entity_Name (Nam2) and then Entity (Prefix (Nam1)) = Entity (Nam2) then Error_Msg_N ("abort may take time to complete?", N); Error_Msg_N ("\deallocation might have no effect?", N); Error_Msg_N ("\safer to wait for termination.?", N); end if; end if; end; Append_To (Stmts, Cleanup_Task (N, Duplicate_Subexpr_No_Checks (Arg))); -- For composite types that contain tasks, recurse over the structure -- to build the selectors for the task subcomponents. elsif Has_Task (Desig_T) then if Is_Record_Type (Desig_T) then Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T)); elsif Is_Array_Type (Desig_T) then Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T)); end if; end if; -- Same for simple protected types. Eventually call Finalize_Protection -- before freeing the PO for each protected component. if Is_Simple_Protected_Type (Desig_T) then Append_To (Stmts, Cleanup_Protected_Object (N, Duplicate_Subexpr_No_Checks (Arg))); elsif Has_Simple_Protected_Object (Desig_T) then if Is_Record_Type (Desig_T) then Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T)); elsif Is_Array_Type (Desig_T) then Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T)); end if; end if; -- Normal processing for non-controlled types Free_Arg := Duplicate_Subexpr_No_Checks (Arg); Free_Node := Make_Free_Statement (Loc, Empty); Append_To (Stmts, Free_Node); Set_Storage_Pool (Free_Node, Pool); -- Deal with storage pool if Present (Pool) then -- Freeing the secondary stack is meaningless if Is_RTE (Pool, RE_SS_Pool) then null; elsif Is_Class_Wide_Type (Etype (Pool)) then -- Case of a class-wide pool type: make a dispatching call -- to Deallocate through the class-wide Deallocate_Any. Set_Procedure_To_Call (Free_Node, RTE (RE_Deallocate_Any)); else -- Case of a specific pool type: make a statically bound call Set_Procedure_To_Call (Free_Node, Find_Prim_Op (Etype (Pool), Name_Deallocate)); end if; end if; if Present (Procedure_To_Call (Free_Node)) then -- For all cases of a Deallocate call, the back-end needs to be -- able to compute the size of the object being freed. This may -- require some adjustments for objects of dynamic size. -- -- If the type is class wide, we generate an implicit type with the -- right dynamic size, so that the deallocate call gets the right -- size parameter computed by GIGI. Same for an access to -- unconstrained packed array. if Is_Class_Wide_Type (Desig_T) or else (Is_Array_Type (Desig_T) and then not Is_Constrained (Desig_T) and then Is_Packed (Desig_T)) then declare Deref : constant Node_Id := Make_Explicit_Dereference (Loc, Duplicate_Subexpr_No_Checks (Arg)); D_Subtyp : Node_Id; D_Type : Entity_Id; begin Set_Etype (Deref, Typ); Set_Parent (Deref, Free_Node); D_Subtyp := Make_Subtype_From_Expr (Deref, Desig_T); if Nkind (D_Subtyp) in N_Has_Entity then D_Type := Entity (D_Subtyp); else D_Type := Make_Defining_Identifier (Loc, New_Internal_Name ('A')); Insert_Action (Deref, Make_Subtype_Declaration (Loc, Defining_Identifier => D_Type, Subtype_Indication => D_Subtyp)); end if; -- Force freezing at the point of the dereference. For the -- class wide case, this avoids having the subtype frozen -- before the equivalent type. Freeze_Itype (D_Type, Deref); Set_Actual_Designated_Subtype (Free_Node, D_Type); end; end if; end if; -- Ada 2005 (AI-251): In case of abstract interface type we must -- displace the pointer to reference the base of the object to -- deallocate its memory, unless we're targetting a VM, in which case -- no special processing is required. -- Generate: -- free (Base_Address (Obj_Ptr)) if Is_Interface (Directly_Designated_Type (Typ)) and then Tagged_Type_Expansion then Set_Expression (Free_Node, Unchecked_Convert_To (Typ, Make_Function_Call (Loc, Name => New_Reference_To (RTE (RE_Base_Address), Loc), Parameter_Associations => New_List ( Unchecked_Convert_To (RTE (RE_Address), Free_Arg))))); -- Generate: -- free (Obj_Ptr) else Set_Expression (Free_Node, Free_Arg); end if; -- Only remaining step is to set result to null, or generate a -- raise of constraint error if the target object is "not null". if Can_Never_Be_Null (Etype (Arg)) then Append_To (Stmts, Make_Raise_Constraint_Error (Loc, Reason => CE_Access_Check_Failed)); else declare Lhs : constant Node_Id := Duplicate_Subexpr_No_Checks (Arg); begin Set_Assignment_OK (Lhs); Append_To (Stmts, Make_Assignment_Statement (Loc, Name => Lhs, Expression => Make_Null (Loc))); end; end if; -- If we know the argument is non-null, then make a block statement -- that contains the required statements, no need for a test. if Arg_Known_Non_Null then Gen_Code := Make_Block_Statement (Loc, Handled_Statement_Sequence => Make_Handled_Sequence_Of_Statements (Loc, Statements => Stmts)); -- If the argument may be null, wrap the statements inside an IF that -- does an explicit test to exclude the null case. else Gen_Code := Make_Implicit_If_Statement (N, Condition => Make_Op_Ne (Loc, Left_Opnd => Duplicate_Subexpr (Arg), Right_Opnd => Make_Null (Loc)), Then_Statements => Stmts); end if; -- Rewrite the call Rewrite (N, Gen_Code); Analyze (N); end Expand_Unc_Deallocation; ----------------------- -- Expand_To_Address -- ----------------------- procedure Expand_To_Address (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Arg : constant Node_Id := First_Actual (N); Obj : Node_Id; begin Remove_Side_Effects (Arg); Obj := Make_Explicit_Dereference (Loc, Relocate_Node (Arg)); Rewrite (N, Make_Conditional_Expression (Loc, Expressions => New_List ( Make_Op_Eq (Loc, Left_Opnd => New_Copy_Tree (Arg), Right_Opnd => Make_Null (Loc)), New_Occurrence_Of (RTE (RE_Null_Address), Loc), Make_Attribute_Reference (Loc, Prefix => Obj, Attribute_Name => Name_Address)))); Analyze_And_Resolve (N, RTE (RE_Address)); end Expand_To_Address; ----------------------- -- Expand_To_Pointer -- ----------------------- procedure Expand_To_Pointer (N : Node_Id) is Arg : constant Node_Id := First_Actual (N); begin Rewrite (N, Unchecked_Convert_To (Etype (N), Arg)); Analyze (N); end Expand_To_Pointer; end Exp_Intr;