1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree; use Atree;
27 with Checks; use Checks;
28 with Einfo; use Einfo;
29 with Elists; use Elists;
30 with Errout; use Errout;
31 with Exp_Atag; use Exp_Atag;
32 with Exp_Ch4; use Exp_Ch4;
33 with Exp_Ch7; use Exp_Ch7;
34 with Exp_Ch11; use Exp_Ch11;
35 with Exp_Code; use Exp_Code;
36 with Exp_Fixd; use Exp_Fixd;
37 with Exp_Util; use Exp_Util;
38 with Freeze; use Freeze;
39 with Namet; use Namet;
40 with Nmake; use Nmake;
41 with Nlists; use Nlists;
43 with Restrict; use Restrict;
44 with Rident; use Rident;
45 with Rtsfind; use Rtsfind;
47 with Sem_Eval; use Sem_Eval;
48 with Sem_Res; use Sem_Res;
49 with Sem_Type; use Sem_Type;
50 with Sem_Util; use Sem_Util;
51 with Sinfo; use Sinfo;
52 with Sinput; use Sinput;
53 with Snames; use Snames;
54 with Stand; use Stand;
55 with Stringt; use Stringt;
56 with Tbuild; use Tbuild;
57 with Uintp; use Uintp;
58 with Urealp; use Urealp;
60 package body Exp_Intr is
62 -----------------------
63 -- Local Subprograms --
64 -----------------------
66 procedure Expand_Is_Negative (N : Node_Id);
67 -- Expand a call to the intrinsic Is_Negative function
69 procedure Expand_Dispatching_Constructor_Call (N : Node_Id);
70 -- Expand a call to an instantiation of Generic_Dispatching_Constructor
71 -- into a dispatching call to the actual subprogram associated with the
72 -- Constructor formal subprogram, passing it the Parameters actual of
73 -- the call to the instantiation and dispatching based on call's Tag
76 procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id);
77 -- Expand a call to Exception_Information/Message/Name. The first
78 -- parameter, N, is the node for the function call, and Ent is the
79 -- entity for the corresponding routine in the Ada.Exceptions package.
81 procedure Expand_Import_Call (N : Node_Id);
82 -- Expand a call to Import_Address/Longest_Integer/Value. The parameter
83 -- N is the node for the function call.
85 procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind);
86 -- Expand an intrinsic shift operation, N and E are from the call to
87 -- Expand_Intrinsic_Call (call node and subprogram spec entity) and
88 -- K is the kind for the shift node
90 procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id);
91 -- Expand a call to an instantiation of Unchecked_Conversion into a node
92 -- N_Unchecked_Type_Conversion.
94 procedure Expand_Unc_Deallocation (N : Node_Id);
95 -- Expand a call to an instantiation of Unchecked_Deallocation into a node
96 -- N_Free_Statement and appropriate context.
98 procedure Expand_To_Address (N : Node_Id);
99 procedure Expand_To_Pointer (N : Node_Id);
100 -- Expand a call to corresponding function, declared in an instance of
101 -- System.Address_To_Access_Conversions.
103 procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id);
104 -- Rewrite the node by the appropriate string or positive constant.
105 -- Nam can be one of the following:
106 -- Name_File - expand string that is the name of source file
107 -- Name_Line - expand integer line number
108 -- Name_Source_Location - expand string of form file:line
109 -- Name_Enclosing_Entity - expand string with name of enclosing entity
111 -----------------------------------------
112 -- Expand_Dispatching_Constructor_Call --
113 -----------------------------------------
115 -- Transform a call to an instantiation of Generic_Dispatching_Constructor
118 -- GDC_Instance (The_Tag, Parameters'Access)
120 -- to a class-wide conversion of a dispatching call to the actual
121 -- associated with the formal subprogram Construct, designating The_Tag
122 -- as the controlling tag of the call:
124 -- T'Class (Construct'Actual (Params)) -- Controlling tag is The_Tag
126 -- which will eventually be expanded to the following:
128 -- T'Class (The_Tag.all (Construct'Actual'Index).all (Params))
130 -- A class-wide membership test is also generated, preceding the call, to
131 -- ensure that the controlling tag denotes a type in T'Class.
133 procedure Expand_Dispatching_Constructor_Call (N : Node_Id) is
134 Loc : constant Source_Ptr := Sloc (N);
135 Tag_Arg : constant Node_Id := First_Actual (N);
136 Param_Arg : constant Node_Id := Next_Actual (Tag_Arg);
137 Subp_Decl : constant Node_Id := Parent (Parent (Entity (Name (N))));
138 Inst_Pkg : constant Node_Id := Parent (Subp_Decl);
139 Act_Rename : Node_Id;
140 Act_Constr : Entity_Id;
141 Iface_Tag : Node_Id := Empty;
142 Cnstr_Call : Node_Id;
143 Result_Typ : Entity_Id;
146 -- The subprogram is the third actual in the instantiation, and is
147 -- retrieved from the corresponding renaming declaration. However,
148 -- freeze nodes may appear before, so we retrieve the declaration
149 -- with an explicit loop.
151 Act_Rename := First (Visible_Declarations (Inst_Pkg));
152 while Nkind (Act_Rename) /= N_Subprogram_Renaming_Declaration loop
156 Act_Constr := Entity (Name (Act_Rename));
157 Result_Typ := Class_Wide_Type (Etype (Act_Constr));
159 -- Ada 2005 (AI-251): If the result is an interface type, the function
160 -- returns a class-wide interface type (otherwise the resulting object
161 -- would be abstract!)
163 if Is_Interface (Etype (Act_Constr)) then
164 Set_Etype (Act_Constr, Result_Typ);
166 -- If the result type is not parent of Tag_Arg then we need to
167 -- locate the tag of the secondary dispatch table.
169 if not Is_Ancestor (Etype (Result_Typ), Etype (Tag_Arg)) then
170 pragma Assert (not Is_Interface (Etype (Tag_Arg)));
173 Make_Object_Declaration (Loc,
174 Defining_Identifier =>
175 Make_Defining_Identifier (Loc, New_Internal_Name ('V')),
177 New_Reference_To (RTE (RE_Tag), Loc),
179 Make_Function_Call (Loc,
180 Name => New_Reference_To (RTE (RE_Secondary_Tag), Loc),
181 Parameter_Associations => New_List (
182 Relocate_Node (Tag_Arg),
184 (Node (First_Elmt (Access_Disp_Table
185 (Etype (Etype (Act_Constr))))),
187 Insert_Action (N, Iface_Tag);
191 -- Create the call to the actual Constructor function
194 Make_Function_Call (Loc,
195 Name => New_Occurrence_Of (Act_Constr, Loc),
196 Parameter_Associations => New_List (Relocate_Node (Param_Arg)));
198 -- Establish its controlling tag from the tag passed to the instance
199 -- The tag may be given by a function call, in which case a temporary
200 -- should be generated now, to prevent out-of-order insertions during
201 -- the expansion of that call when stack-checking is enabled.
203 if Present (Iface_Tag) then
204 Set_Controlling_Argument (Cnstr_Call,
205 New_Occurrence_Of (Defining_Identifier (Iface_Tag), Loc));
207 Remove_Side_Effects (Tag_Arg);
208 Set_Controlling_Argument (Cnstr_Call,
209 Relocate_Node (Tag_Arg));
212 -- Rewrite and analyze the call to the instance as a class-wide
213 -- conversion of the call to the actual constructor.
215 Rewrite (N, Convert_To (Result_Typ, Cnstr_Call));
216 Analyze_And_Resolve (N, Etype (Act_Constr));
218 -- Do not generate a run-time check on the built object if tag
219 -- checks are suppressed for the result type or VM_Target /= No_VM
221 if Tag_Checks_Suppressed (Etype (Result_Typ))
222 or else not Tagged_Type_Expansion
226 -- Generate a class-wide membership test to ensure that the call's tag
227 -- argument denotes a type within the class. We must keep separate the
228 -- case in which the Result_Type of the constructor function is a tagged
229 -- type from the case in which it is an abstract interface because the
230 -- run-time subprogram required to check these cases differ (and have
231 -- one difference in their parameters profile).
233 -- Call CW_Membership if the Result_Type is a tagged type to look for
234 -- the tag in the table of ancestor tags.
236 elsif not Is_Interface (Result_Typ) then
238 Make_Implicit_If_Statement (N,
241 Build_CW_Membership (Loc,
242 Obj_Tag_Node => Duplicate_Subexpr (Tag_Arg),
245 Node (First_Elmt (Access_Disp_Table (
246 Root_Type (Result_Typ)))), Loc))),
248 New_List (Make_Raise_Statement (Loc,
249 New_Occurrence_Of (RTE (RE_Tag_Error), Loc)))));
251 -- Call IW_Membership test if the Result_Type is an abstract interface
252 -- to look for the tag in the table of interface tags.
256 Make_Implicit_If_Statement (N,
259 Make_Function_Call (Loc,
260 Name => New_Occurrence_Of (RTE (RE_IW_Membership), Loc),
261 Parameter_Associations => New_List (
262 Make_Attribute_Reference (Loc,
263 Prefix => Duplicate_Subexpr (Tag_Arg),
264 Attribute_Name => Name_Address),
267 Node (First_Elmt (Access_Disp_Table (
268 Root_Type (Result_Typ)))), Loc)))),
271 Make_Raise_Statement (Loc,
272 Name => New_Occurrence_Of (RTE (RE_Tag_Error), Loc)))));
274 end Expand_Dispatching_Constructor_Call;
276 ---------------------------
277 -- Expand_Exception_Call --
278 ---------------------------
280 -- If the function call is not within an exception handler, then the call
281 -- is replaced by a null string. Otherwise the appropriate routine in
282 -- Ada.Exceptions is called passing the choice parameter specification
283 -- from the enclosing handler. If the enclosing handler lacks a choice
284 -- parameter, then one is supplied.
286 procedure Expand_Exception_Call (N : Node_Id; Ent : RE_Id) is
287 Loc : constant Source_Ptr := Sloc (N);
292 -- Climb up parents to see if we are in exception handler
296 -- Case of not in exception handler, replace by null string
300 Make_String_Literal (Loc,
304 -- Case of in exception handler
306 elsif Nkind (P) = N_Exception_Handler then
308 -- Handler cannot be used for a local raise, and furthermore, this
309 -- is a violation of the No_Exception_Propagation restriction.
311 Set_Local_Raise_Not_OK (P);
312 Check_Restriction (No_Exception_Propagation, N);
314 -- If no choice parameter present, then put one there. Note that
315 -- we do not need to put it on the entity chain, since no one will
316 -- be referencing it by normal visibility methods.
318 if No (Choice_Parameter (P)) then
319 E := Make_Defining_Identifier (Loc, New_Internal_Name ('E'));
320 Set_Choice_Parameter (P, E);
321 Set_Ekind (E, E_Variable);
322 Set_Etype (E, RTE (RE_Exception_Occurrence));
323 Set_Scope (E, Current_Scope);
327 Make_Function_Call (Loc,
328 Name => New_Occurrence_Of (RTE (Ent), Loc),
329 Parameter_Associations => New_List (
330 New_Occurrence_Of (Choice_Parameter (P), Loc))));
340 Analyze_And_Resolve (N, Standard_String);
341 end Expand_Exception_Call;
343 ------------------------
344 -- Expand_Import_Call --
345 ------------------------
347 -- The function call must have a static string as its argument. We create
348 -- a dummy variable which uses this string as the external name in an
349 -- Import pragma. The result is then obtained as the address of this
350 -- dummy variable, converted to the appropriate target type.
352 procedure Expand_Import_Call (N : Node_Id) is
353 Loc : constant Source_Ptr := Sloc (N);
354 Ent : constant Entity_Id := Entity (Name (N));
355 Str : constant Node_Id := First_Actual (N);
359 Dum := Make_Defining_Identifier (Loc, New_Internal_Name ('D'));
361 Insert_Actions (N, New_List (
362 Make_Object_Declaration (Loc,
363 Defining_Identifier => Dum,
365 New_Occurrence_Of (Standard_Character, Loc)),
368 Chars => Name_Import,
369 Pragma_Argument_Associations => New_List (
370 Make_Pragma_Argument_Association (Loc,
371 Expression => Make_Identifier (Loc, Name_Ada)),
373 Make_Pragma_Argument_Association (Loc,
374 Expression => Make_Identifier (Loc, Chars (Dum))),
376 Make_Pragma_Argument_Association (Loc,
377 Chars => Name_Link_Name,
378 Expression => Relocate_Node (Str))))));
381 Unchecked_Convert_To (Etype (Ent),
382 Make_Attribute_Reference (Loc,
383 Prefix => Make_Identifier (Loc, Chars (Dum)),
384 Attribute_Name => Name_Address)));
386 Analyze_And_Resolve (N, Etype (Ent));
387 end Expand_Import_Call;
389 ---------------------------
390 -- Expand_Intrinsic_Call --
391 ---------------------------
393 procedure Expand_Intrinsic_Call (N : Node_Id; E : Entity_Id) is
397 -- If an external name is specified for the intrinsic, it is handled
398 -- by the back-end: leave the call node unchanged for now.
400 if Present (Interface_Name (E)) then
404 -- If the intrinsic subprogram is generic, gets its original name
406 if Present (Parent (E))
407 and then Present (Generic_Parent (Parent (E)))
409 Nam := Chars (Generic_Parent (Parent (E)));
414 if Nam = Name_Asm then
417 elsif Nam = Name_Divide then
418 Expand_Decimal_Divide_Call (N);
420 elsif Nam = Name_Exception_Information then
421 Expand_Exception_Call (N, RE_Exception_Information);
423 elsif Nam = Name_Exception_Message then
424 Expand_Exception_Call (N, RE_Exception_Message);
426 elsif Nam = Name_Exception_Name then
427 Expand_Exception_Call (N, RE_Exception_Name_Simple);
429 elsif Nam = Name_Generic_Dispatching_Constructor then
430 Expand_Dispatching_Constructor_Call (N);
432 elsif Nam = Name_Import_Address
434 Nam = Name_Import_Largest_Value
436 Nam = Name_Import_Value
438 Expand_Import_Call (N);
440 elsif Nam = Name_Is_Negative then
441 Expand_Is_Negative (N);
443 elsif Nam = Name_Rotate_Left then
444 Expand_Shift (N, E, N_Op_Rotate_Left);
446 elsif Nam = Name_Rotate_Right then
447 Expand_Shift (N, E, N_Op_Rotate_Right);
449 elsif Nam = Name_Shift_Left then
450 Expand_Shift (N, E, N_Op_Shift_Left);
452 elsif Nam = Name_Shift_Right then
453 Expand_Shift (N, E, N_Op_Shift_Right);
455 elsif Nam = Name_Shift_Right_Arithmetic then
456 Expand_Shift (N, E, N_Op_Shift_Right_Arithmetic);
458 elsif Nam = Name_Unchecked_Conversion then
459 Expand_Unc_Conversion (N, E);
461 elsif Nam = Name_Unchecked_Deallocation then
462 Expand_Unc_Deallocation (N);
464 elsif Nam = Name_To_Address then
465 Expand_To_Address (N);
467 elsif Nam = Name_To_Pointer then
468 Expand_To_Pointer (N);
470 elsif Nam = Name_File
471 or else Nam = Name_Line
472 or else Nam = Name_Source_Location
473 or else Nam = Name_Enclosing_Entity
475 Expand_Source_Info (N, Nam);
477 -- If we have a renaming, expand the call to the original operation,
478 -- which must itself be intrinsic, since renaming requires matching
479 -- conventions and this has already been checked.
481 elsif Present (Alias (E)) then
482 Expand_Intrinsic_Call (N, Alias (E));
484 -- The only other case is where an external name was specified,
485 -- since this is the only way that an otherwise unrecognized
486 -- name could escape the checking in Sem_Prag. Nothing needs
487 -- to be done in such a case, since we pass such a call to the
488 -- back end unchanged.
493 end Expand_Intrinsic_Call;
495 ------------------------
496 -- Expand_Is_Negative --
497 ------------------------
499 procedure Expand_Is_Negative (N : Node_Id) is
500 Loc : constant Source_Ptr := Sloc (N);
501 Opnd : constant Node_Id := Relocate_Node (First_Actual (N));
505 -- We replace the function call by the following expression
507 -- if Opnd < 0.0 then
510 -- if Opnd > 0.0 then
513 -- Float_Unsigned!(Float (Opnd)) /= 0
518 Make_Conditional_Expression (Loc,
519 Expressions => New_List (
521 Left_Opnd => Duplicate_Subexpr (Opnd),
522 Right_Opnd => Make_Real_Literal (Loc, Ureal_0)),
524 New_Occurrence_Of (Standard_True, Loc),
526 Make_Conditional_Expression (Loc,
527 Expressions => New_List (
529 Left_Opnd => Duplicate_Subexpr_No_Checks (Opnd),
530 Right_Opnd => Make_Real_Literal (Loc, Ureal_0)),
532 New_Occurrence_Of (Standard_False, Loc),
537 (RTE (RE_Float_Unsigned),
540 Duplicate_Subexpr_No_Checks (Opnd))),
542 Make_Integer_Literal (Loc, 0)))))));
544 Analyze_And_Resolve (N, Standard_Boolean);
545 end Expand_Is_Negative;
551 -- This procedure is used to convert a call to a shift function to the
552 -- corresponding operator node. This conversion is not done by the usual
553 -- circuit for converting calls to operator functions (e.g. "+"(1,2)) to
554 -- operator nodes, because shifts are not predefined operators.
556 -- As a result, whenever a shift is used in the source program, it will
557 -- remain as a call until converted by this routine to the operator node
558 -- form which Gigi is expecting to see.
560 -- Note: it is possible for the expander to generate shift operator nodes
561 -- directly, which will be analyzed in the normal manner by calling Analyze
562 -- and Resolve. Such shift operator nodes will not be seen by Expand_Shift.
564 procedure Expand_Shift (N : Node_Id; E : Entity_Id; K : Node_Kind) is
565 Loc : constant Source_Ptr := Sloc (N);
566 Typ : constant Entity_Id := Etype (N);
567 Left : constant Node_Id := First_Actual (N);
568 Right : constant Node_Id := Next_Actual (Left);
569 Ltyp : constant Node_Id := Etype (Left);
570 Rtyp : constant Node_Id := Etype (Right);
574 Snode := New_Node (K, Loc);
575 Set_Left_Opnd (Snode, Relocate_Node (Left));
576 Set_Right_Opnd (Snode, Relocate_Node (Right));
577 Set_Chars (Snode, Chars (E));
578 Set_Etype (Snode, Base_Type (Typ));
579 Set_Entity (Snode, E);
581 if Compile_Time_Known_Value (Type_High_Bound (Rtyp))
582 and then Expr_Value (Type_High_Bound (Rtyp)) < Esize (Ltyp)
584 Set_Shift_Count_OK (Snode, True);
587 -- Do the rewrite. Note that we don't call Analyze and Resolve on
588 -- this node, because it already got analyzed and resolved when
589 -- it was a function call!
595 ------------------------
596 -- Expand_Source_Info --
597 ------------------------
599 procedure Expand_Source_Info (N : Node_Id; Nam : Name_Id) is
600 Loc : constant Source_Ptr := Sloc (N);
603 procedure Write_Entity_Name (E : Entity_Id);
604 -- Recursive procedure to construct string for qualified name of
605 -- enclosing program unit. The qualification stops at an enclosing
606 -- scope has no source name (block or loop). If entity is a subprogram
607 -- instance, skip enclosing wrapper package.
609 -----------------------
610 -- Write_Entity_Name --
611 -----------------------
613 procedure Write_Entity_Name (E : Entity_Id) is
615 TDef : constant Source_Buffer_Ptr :=
616 Source_Text (Get_Source_File_Index (Sloc (E)));
619 -- Nothing to do if at outer level
621 if Scope (E) = Standard_Standard then
624 -- If scope comes from source, write its name
626 elsif Comes_From_Source (Scope (E)) then
627 Write_Entity_Name (Scope (E));
628 Add_Char_To_Name_Buffer ('.');
630 -- If in wrapper package skip past it
632 elsif Is_Wrapper_Package (Scope (E)) then
633 Write_Entity_Name (Scope (Scope (E)));
634 Add_Char_To_Name_Buffer ('.');
636 -- Otherwise nothing to output (happens in unnamed block statements)
642 -- Loop to output the name
644 -- is this right wrt wide char encodings ??? (no!)
647 while TDef (SDef) in '0' .. '9'
648 or else TDef (SDef) >= 'A'
649 or else TDef (SDef) = ASCII.ESC
651 Add_Char_To_Name_Buffer (TDef (SDef));
654 end Write_Entity_Name;
656 -- Start of processing for Expand_Source_Info
661 if Nam = Name_Line then
663 Make_Integer_Literal (Loc,
664 Intval => UI_From_Int (Int (Get_Logical_Line_Number (Loc)))));
665 Analyze_And_Resolve (N, Standard_Positive);
674 Get_Decoded_Name_String
675 (Reference_Name (Get_Source_File_Index (Loc)));
677 when Name_Source_Location =>
678 Build_Location_String (Loc);
680 when Name_Enclosing_Entity =>
682 -- Skip enclosing blocks to reach enclosing unit
684 Ent := Current_Scope;
685 while Present (Ent) loop
686 exit when Ekind (Ent) /= E_Block
687 and then Ekind (Ent) /= E_Loop;
691 -- Ent now points to the relevant defining entity
693 Write_Entity_Name (Ent);
700 Make_String_Literal (Loc,
701 Strval => String_From_Name_Buffer));
702 Analyze_And_Resolve (N, Standard_String);
705 Set_Is_Static_Expression (N);
706 end Expand_Source_Info;
708 ---------------------------
709 -- Expand_Unc_Conversion --
710 ---------------------------
712 procedure Expand_Unc_Conversion (N : Node_Id; E : Entity_Id) is
713 Func : constant Entity_Id := Entity (Name (N));
719 -- Rewrite as unchecked conversion node. Note that we must convert
720 -- the operand to the formal type of the input parameter of the
721 -- function, so that the resulting N_Unchecked_Type_Conversion
722 -- call indicates the correct types for Gigi.
724 -- Right now, we only do this if a scalar type is involved. It is
725 -- not clear if it is needed in other cases. If we do attempt to
726 -- do the conversion unconditionally, it crashes 3411-018. To be
727 -- investigated further ???
729 Conv := Relocate_Node (First_Actual (N));
730 Ftyp := Etype (First_Formal (Func));
732 if Is_Scalar_Type (Ftyp) then
733 Conv := Convert_To (Ftyp, Conv);
734 Set_Parent (Conv, N);
735 Analyze_And_Resolve (Conv);
738 -- The instantiation of Unchecked_Conversion creates a wrapper package,
739 -- and the target type is declared as a subtype of the actual. Recover
740 -- the actual, which is the subtype indic. in the subtype declaration
741 -- for the target type. This is semantically correct, and avoids
742 -- anomalies with access subtypes. For entities, leave type as is.
744 -- We do the analysis here, because we do not want the compiler
745 -- to try to optimize or otherwise reorganize the unchecked
750 if Is_Entity_Name (Conv) then
753 elsif Nkind (Parent (Ttyp)) = N_Subtype_Declaration then
754 Ttyp := Entity (Subtype_Indication (Parent (Etype (E))));
756 elsif Is_Itype (Ttyp) then
758 Entity (Subtype_Indication (Associated_Node_For_Itype (Ttyp)));
763 Rewrite (N, Unchecked_Convert_To (Ttyp, Conv));
767 if Nkind (N) = N_Unchecked_Type_Conversion then
768 Expand_N_Unchecked_Type_Conversion (N);
770 end Expand_Unc_Conversion;
772 -----------------------------
773 -- Expand_Unc_Deallocation --
774 -----------------------------
776 -- Generate the following Code :
778 -- if Arg /= null then
779 -- <Finalize_Call> (.., T'Class(Arg.all), ..); -- for controlled types
784 -- For a task, we also generate a call to Free_Task to ensure that the
785 -- task itself is freed if it is terminated, ditto for a simple protected
786 -- object, with a call to Finalize_Protection. For composite types that
787 -- have tasks or simple protected objects as components, we traverse the
788 -- structures to find and terminate those components.
790 procedure Expand_Unc_Deallocation (N : Node_Id) is
791 Loc : constant Source_Ptr := Sloc (N);
792 Arg : constant Node_Id := First_Actual (N);
793 Typ : constant Entity_Id := Etype (Arg);
794 Stmts : constant List_Id := New_List;
795 Rtyp : constant Entity_Id := Underlying_Type (Root_Type (Typ));
796 Pool : constant Entity_Id := Associated_Storage_Pool (Rtyp);
798 Desig_T : constant Entity_Id := Designated_Type (Typ);
806 Arg_Known_Non_Null : constant Boolean := Known_Non_Null (N);
807 -- This captures whether we know the argument to be non-null so that
808 -- we can avoid the test. The reason that we need to capture this is
809 -- that we analyze some generated statements before properly attaching
810 -- them to the tree, and that can disturb current value settings.
813 if No_Pool_Assigned (Rtyp) then
814 Error_Msg_N ("?deallocation from empty storage pool!", N);
817 -- Nothing to do if we know the argument is null
819 if Known_Null (N) then
823 -- Processing for pointer to controlled type
825 if Needs_Finalization (Desig_T) then
827 Make_Explicit_Dereference (Loc,
828 Prefix => Duplicate_Subexpr_No_Checks (Arg));
830 -- If the type is tagged, then we must force dispatching on the
831 -- finalization call because the designated type may not be the
832 -- actual type of the object.
834 if Is_Tagged_Type (Desig_T)
835 and then not Is_Class_Wide_Type (Desig_T)
837 Deref := Unchecked_Convert_To (Class_Wide_Type (Desig_T), Deref);
839 elsif not Is_Tagged_Type (Desig_T) then
841 -- Set type of result, to force a conversion when needed (see
842 -- exp_ch7, Convert_View), given that Deep_Finalize may be
843 -- inherited from the parent type, and we need the type of the
844 -- expression to see whether the conversion is in fact needed.
846 Set_Etype (Deref, Desig_T);
853 With_Detach => New_Reference_To (Standard_True, Loc));
855 if Abort_Allowed then
856 Prepend_To (Free_Cod,
857 Build_Runtime_Call (Loc, RE_Abort_Defer));
860 Make_Block_Statement (Loc, Handled_Statement_Sequence =>
861 Make_Handled_Sequence_Of_Statements (Loc,
862 Statements => Free_Cod,
864 New_Occurrence_Of (RTE (RE_Abort_Undefer_Direct), Loc)));
866 -- We now expand the exception (at end) handler. We set a
867 -- temporary parent pointer since we have not attached Blk
872 Expand_At_End_Handler
873 (Handled_Statement_Sequence (Blk), Entity (Identifier (Blk)));
876 -- We kill saved current values, since analyzing statements not
877 -- properly attached to the tree can set wrong current values.
882 Append_List_To (Stmts, Free_Cod);
886 -- For a task type, call Free_Task before freeing the ATCB
888 if Is_Task_Type (Desig_T) then
890 Stat : Node_Id := Prev (N);
895 -- An Abort followed by a Free will not do what the user
896 -- expects, because the abort is not immediate. This is
897 -- worth a friendly warning.
900 and then not Comes_From_Source (Original_Node (Stat))
906 and then Nkind (Original_Node (Stat)) = N_Abort_Statement
908 Stat := Original_Node (Stat);
909 Nam1 := First (Names (Stat));
910 Nam2 := Original_Node (First (Parameter_Associations (N)));
912 if Nkind (Nam1) = N_Explicit_Dereference
913 and then Is_Entity_Name (Prefix (Nam1))
914 and then Is_Entity_Name (Nam2)
915 and then Entity (Prefix (Nam1)) = Entity (Nam2)
917 Error_Msg_N ("abort may take time to complete?", N);
918 Error_Msg_N ("\deallocation might have no effect?", N);
919 Error_Msg_N ("\safer to wait for termination.?", N);
925 (Stmts, Cleanup_Task (N, Duplicate_Subexpr_No_Checks (Arg)));
927 -- For composite types that contain tasks, recurse over the structure
928 -- to build the selectors for the task subcomponents.
930 elsif Has_Task (Desig_T) then
931 if Is_Record_Type (Desig_T) then
932 Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T));
934 elsif Is_Array_Type (Desig_T) then
935 Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T));
939 -- Same for simple protected types. Eventually call Finalize_Protection
940 -- before freeing the PO for each protected component.
942 if Is_Simple_Protected_Type (Desig_T) then
944 Cleanup_Protected_Object (N, Duplicate_Subexpr_No_Checks (Arg)));
946 elsif Has_Simple_Protected_Object (Desig_T) then
947 if Is_Record_Type (Desig_T) then
948 Append_List_To (Stmts, Cleanup_Record (N, Arg, Desig_T));
949 elsif Is_Array_Type (Desig_T) then
950 Append_List_To (Stmts, Cleanup_Array (N, Arg, Desig_T));
954 -- Normal processing for non-controlled types
956 Free_Arg := Duplicate_Subexpr_No_Checks (Arg);
957 Free_Node := Make_Free_Statement (Loc, Empty);
958 Append_To (Stmts, Free_Node);
959 Set_Storage_Pool (Free_Node, Pool);
961 -- Deal with storage pool
963 if Present (Pool) then
965 -- Freeing the secondary stack is meaningless
967 if Is_RTE (Pool, RE_SS_Pool) then
970 elsif Is_Class_Wide_Type (Etype (Pool)) then
972 -- Case of a class-wide pool type: make a dispatching call
973 -- to Deallocate through the class-wide Deallocate_Any.
975 Set_Procedure_To_Call (Free_Node,
976 RTE (RE_Deallocate_Any));
979 -- Case of a specific pool type: make a statically bound call
981 Set_Procedure_To_Call (Free_Node,
982 Find_Prim_Op (Etype (Pool), Name_Deallocate));
986 if Present (Procedure_To_Call (Free_Node)) then
988 -- For all cases of a Deallocate call, the back-end needs to be
989 -- able to compute the size of the object being freed. This may
990 -- require some adjustments for objects of dynamic size.
992 -- If the type is class wide, we generate an implicit type with the
993 -- right dynamic size, so that the deallocate call gets the right
994 -- size parameter computed by GIGI. Same for an access to
995 -- unconstrained packed array.
997 if Is_Class_Wide_Type (Desig_T)
999 (Is_Array_Type (Desig_T)
1000 and then not Is_Constrained (Desig_T)
1001 and then Is_Packed (Desig_T))
1004 Deref : constant Node_Id :=
1005 Make_Explicit_Dereference (Loc,
1006 Duplicate_Subexpr_No_Checks (Arg));
1011 Set_Etype (Deref, Typ);
1012 Set_Parent (Deref, Free_Node);
1013 D_Subtyp := Make_Subtype_From_Expr (Deref, Desig_T);
1015 if Nkind (D_Subtyp) in N_Has_Entity then
1016 D_Type := Entity (D_Subtyp);
1019 D_Type := Make_Defining_Identifier (Loc,
1020 New_Internal_Name ('A'));
1021 Insert_Action (Deref,
1022 Make_Subtype_Declaration (Loc,
1023 Defining_Identifier => D_Type,
1024 Subtype_Indication => D_Subtyp));
1028 -- Force freezing at the point of the dereference. For the
1029 -- class wide case, this avoids having the subtype frozen
1030 -- before the equivalent type.
1032 Freeze_Itype (D_Type, Deref);
1034 Set_Actual_Designated_Subtype (Free_Node, D_Type);
1040 -- Ada 2005 (AI-251): In case of abstract interface type we must
1041 -- displace the pointer to reference the base of the object to
1042 -- deallocate its memory, unless we're targetting a VM, in which case
1043 -- no special processing is required.
1046 -- free (Base_Address (Obj_Ptr))
1048 if Is_Interface (Directly_Designated_Type (Typ))
1049 and then Tagged_Type_Expansion
1051 Set_Expression (Free_Node,
1052 Unchecked_Convert_To (Typ,
1053 Make_Function_Call (Loc,
1054 Name => New_Reference_To (RTE (RE_Base_Address), Loc),
1055 Parameter_Associations => New_List (
1056 Unchecked_Convert_To (RTE (RE_Address), Free_Arg)))));
1062 Set_Expression (Free_Node, Free_Arg);
1065 -- Only remaining step is to set result to null, or generate a
1066 -- raise of constraint error if the target object is "not null".
1068 if Can_Never_Be_Null (Etype (Arg)) then
1070 Make_Raise_Constraint_Error (Loc,
1071 Reason => CE_Access_Check_Failed));
1075 Lhs : constant Node_Id := Duplicate_Subexpr_No_Checks (Arg);
1077 Set_Assignment_OK (Lhs);
1079 Make_Assignment_Statement (Loc,
1081 Expression => Make_Null (Loc)));
1085 -- If we know the argument is non-null, then make a block statement
1086 -- that contains the required statements, no need for a test.
1088 if Arg_Known_Non_Null then
1090 Make_Block_Statement (Loc,
1091 Handled_Statement_Sequence =>
1092 Make_Handled_Sequence_Of_Statements (Loc,
1093 Statements => Stmts));
1095 -- If the argument may be null, wrap the statements inside an IF that
1096 -- does an explicit test to exclude the null case.
1100 Make_Implicit_If_Statement (N,
1103 Left_Opnd => Duplicate_Subexpr (Arg),
1104 Right_Opnd => Make_Null (Loc)),
1105 Then_Statements => Stmts);
1110 Rewrite (N, Gen_Code);
1112 end Expand_Unc_Deallocation;
1114 -----------------------
1115 -- Expand_To_Address --
1116 -----------------------
1118 procedure Expand_To_Address (N : Node_Id) is
1119 Loc : constant Source_Ptr := Sloc (N);
1120 Arg : constant Node_Id := First_Actual (N);
1124 Remove_Side_Effects (Arg);
1126 Obj := Make_Explicit_Dereference (Loc, Relocate_Node (Arg));
1129 Make_Conditional_Expression (Loc,
1130 Expressions => New_List (
1132 Left_Opnd => New_Copy_Tree (Arg),
1133 Right_Opnd => Make_Null (Loc)),
1134 New_Occurrence_Of (RTE (RE_Null_Address), Loc),
1135 Make_Attribute_Reference (Loc,
1137 Attribute_Name => Name_Address))));
1139 Analyze_And_Resolve (N, RTE (RE_Address));
1140 end Expand_To_Address;
1142 -----------------------
1143 -- Expand_To_Pointer --
1144 -----------------------
1146 procedure Expand_To_Pointer (N : Node_Id) is
1147 Arg : constant Node_Id := First_Actual (N);
1150 Rewrite (N, Unchecked_Convert_To (Etype (N), Arg));
1152 end Expand_To_Pointer;