1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 2014-2018, 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 Debug
; use Debug
;
28 with Einfo
; use Einfo
;
29 with Elists
; use Elists
;
31 with Namet
; use Namet
;
32 with Nlists
; use Nlists
;
33 with Nmake
; use Nmake
;
35 with Output
; use Output
;
36 with Rtsfind
; use Rtsfind
;
38 with Sem_Aux
; use Sem_Aux
;
39 with Sem_Ch8
; use Sem_Ch8
;
40 with Sem_Mech
; use Sem_Mech
;
41 with Sem_Res
; use Sem_Res
;
42 with Sem_Util
; use Sem_Util
;
43 with Sinfo
; use Sinfo
;
44 with Sinput
; use Sinput
;
45 with Snames
; use Snames
;
46 with Stand
; use Stand
;
47 with Tbuild
; use Tbuild
;
48 with Uintp
; use Uintp
;
50 package body Exp_Unst
is
52 -----------------------
53 -- Local Subprograms --
54 -----------------------
56 procedure Unnest_Subprogram
(Subp
: Entity_Id
; Subp_Body
: Node_Id
);
57 -- Subp is a library-level subprogram which has nested subprograms, and
58 -- Subp_Body is the corresponding N_Subprogram_Body node. This procedure
59 -- declares the AREC types and objects, adds assignments to the AREC record
60 -- as required, defines the xxxPTR types for uplevel referenced objects,
61 -- adds the ARECP parameter to all nested subprograms which need it, and
62 -- modifies all uplevel references appropriately.
68 -- Table to record calls within the nest being analyzed. These are the
69 -- calls which may need to have an AREC actual added. This table is built
70 -- new for each subprogram nest and cleared at the end of processing each
73 type Call_Entry
is record
78 -- Entity of the subprogram containing the call (can be at any level)
81 -- Entity of the subprogram called (always at level 2 or higher). Note
82 -- that in accordance with the basic rules of nesting, the level of To
83 -- is either less than or equal to the level of From, or one greater.
86 package Calls
is new Table
.Table
(
87 Table_Component_Type
=> Call_Entry
,
88 Table_Index_Type
=> Nat
,
91 Table_Increment
=> 200,
92 Table_Name
=> "Unnest_Calls");
93 -- Records each call within the outer subprogram and all nested subprograms
94 -- that are to other subprograms nested within the outer subprogram. These
95 -- are the calls that may need an additional parameter.
97 procedure Append_Unique_Call
(Call
: Call_Entry
);
98 -- Append a call entry to the Calls table. A check is made to see if the
99 -- table already contains this entry and if so it has no effect.
101 ----------------------------------
102 -- Subprograms For Fat Pointers --
103 ----------------------------------
105 function Build_Access_Type_Decl
107 Scop
: Entity_Id
) return Node_Id
;
108 -- For an uplevel reference that involves an unconstrained array type,
109 -- build an access type declaration for the corresponding activation
110 -- record component. The relevant attributes of the access type are
111 -- set here to avoid a full analysis that would require a scope stack.
113 function Needs_Fat_Pointer
(E
: Entity_Id
) return Boolean;
114 -- A formal parameter of an unconstrained array type that appears in an
115 -- uplevel reference requires the construction of an access type, to be
116 -- used in the corresponding component declaration.
122 -- Table to record explicit uplevel references to objects (variables,
123 -- constants, formal parameters). These are the references that will
124 -- need rewriting to use the activation table (AREC) pointers. Also
125 -- included are implicit and explicit uplevel references to types, but
126 -- these do not get rewritten by the front end. This table is built new
127 -- for each subprogram nest and cleared at the end of processing each
130 type Uref_Entry
is record
132 -- The reference itself. For objects this is always an entity reference
133 -- and the referenced entity will have its Is_Uplevel_Referenced_Entity
134 -- flag set and will appear in the Uplevel_Referenced_Entities list of
135 -- the subprogram declaring this entity.
138 -- The Entity_Id of the uplevel referenced object or type
141 -- The entity for the subprogram immediately containing this entity
144 -- The entity for the subprogram containing the referenced entity. Note
145 -- that the level of Callee must be less than the level of Caller, since
146 -- this is an uplevel reference.
149 package Urefs
is new Table
.Table
(
150 Table_Component_Type
=> Uref_Entry
,
151 Table_Index_Type
=> Nat
,
152 Table_Low_Bound
=> 1,
153 Table_Initial
=> 100,
154 Table_Increment
=> 200,
155 Table_Name
=> "Unnest_Urefs");
157 ------------------------
158 -- Append_Unique_Call --
159 ------------------------
161 procedure Append_Unique_Call
(Call
: Call_Entry
) is
163 for J
in Calls
.First
.. Calls
.Last
loop
164 if Calls
.Table
(J
) = Call
then
170 end Append_Unique_Call
;
172 -----------------------------
173 -- Build_Access_Type_Decl --
174 -----------------------------
176 function Build_Access_Type_Decl
178 Scop
: Entity_Id
) return Node_Id
180 Loc
: constant Source_Ptr
:= Sloc
(E
);
184 Typ
:= Make_Temporary
(Loc
, 'S');
185 Set_Ekind
(Typ
, E_General_Access_Type
);
186 Set_Etype
(Typ
, Typ
);
187 Set_Scope
(Typ
, Scop
);
188 Set_Directly_Designated_Type
(Typ
, Etype
(E
));
191 Make_Full_Type_Declaration
(Loc
,
192 Defining_Identifier
=> Typ
,
194 Make_Access_To_Object_Definition
(Loc
,
195 Subtype_Indication
=> New_Occurrence_Of
(Etype
(E
), Loc
)));
196 end Build_Access_Type_Decl
;
202 function Get_Level
(Subp
: Entity_Id
; Sub
: Entity_Id
) return Nat
is
214 S
:= Enclosing_Subprogram
(S
);
219 --------------------------
220 -- In_Synchronized_Unit --
221 --------------------------
223 function In_Synchronized_Unit
(Subp
: Entity_Id
) return Boolean is
224 S
: Entity_Id
:= Scope
(Subp
);
227 while Present
(S
) and then S
/= Standard_Standard
loop
228 if Is_Concurrent_Type
(S
) then
236 end In_Synchronized_Unit
;
238 -----------------------
239 -- Needs_Fat_Pointer --
240 -----------------------
242 function Needs_Fat_Pointer
(E
: Entity_Id
) return Boolean is
245 and then Is_Array_Type
(Etype
(E
))
246 and then not Is_Constrained
(Etype
(E
));
247 end Needs_Fat_Pointer
;
253 function Subp_Index
(Sub
: Entity_Id
) return SI_Type
is
254 E
: Entity_Id
:= Sub
;
257 pragma Assert
(Is_Subprogram
(E
));
259 if Subps_Index
(E
) = Uint_0
then
260 E
:= Ultimate_Alias
(E
);
262 if Ekind
(E
) = E_Function
263 and then Rewritten_For_C
(E
)
264 and then Present
(Corresponding_Procedure
(E
))
266 E
:= Corresponding_Procedure
(E
);
270 pragma Assert
(Subps_Index
(E
) /= Uint_0
);
271 return SI_Type
(UI_To_Int
(Subps_Index
(E
)));
274 -----------------------
275 -- Unnest_Subprogram --
276 -----------------------
278 procedure Unnest_Subprogram
(Subp
: Entity_Id
; Subp_Body
: Node_Id
) is
279 function AREC_Name
(J
: Pos
; S
: String) return Name_Id
;
280 -- Returns name for string ARECjS, where j is the decimal value of j
282 function Enclosing_Subp
(Subp
: SI_Type
) return SI_Type
;
283 -- Subp is the index of a subprogram which has a Lev greater than 1.
284 -- This function returns the index of the enclosing subprogram which
285 -- will have a Lev value one less than this.
287 function Img_Pos
(N
: Pos
) return String;
288 -- Return image of N without leading blank
293 Clist
: List_Id
) return Name_Id
;
294 -- This function returns the name to be used in the activation record to
295 -- reference the variable uplevel. Clist is the list of components that
296 -- have been created in the activation record so far. Normally the name
297 -- is just a copy of the Chars field of the entity. The exception is
298 -- when the name has already been used, in which case we suffix the name
299 -- with the index value Index to avoid duplication. This happens with
300 -- declare blocks and generic parameters at least.
306 function AREC_Name
(J
: Pos
; S
: String) return Name_Id
is
308 return Name_Find
("AREC" & Img_Pos
(J
) & S
);
315 function Enclosing_Subp
(Subp
: SI_Type
) return SI_Type
is
316 STJ
: Subp_Entry
renames Subps
.Table
(Subp
);
317 Ret
: constant SI_Type
:= Subp_Index
(Enclosing_Subprogram
(STJ
.Ent
));
319 pragma Assert
(STJ
.Lev
> 1);
320 pragma Assert
(Subps
.Table
(Ret
).Lev
= STJ
.Lev
- 1);
328 function Img_Pos
(N
: Pos
) return String is
329 Buf
: String (1 .. 20);
337 Buf
(Ptr
) := Character'Val (48 + NV
mod 10);
342 return Buf
(Ptr
+ 1 .. Buf
'Last);
352 Clist
: List_Id
) return Name_Id
361 elsif Chars
(Defining_Identifier
(C
)) = Chars
(Ent
) then
363 Name_Find
(Get_Name_String
(Chars
(Ent
)) & Img_Pos
(Index
));
370 -- Start of processing for Unnest_Subprogram
373 -- Nothing to do inside a generic (all processing is for instance)
375 if Inside_A_Generic
then
379 -- If the main unit is a package body then we need to examine the spec
380 -- to determine whether the main unit is generic (the scope stack is not
381 -- present when this is called on the main unit).
383 if Ekind
(Cunit_Entity
(Main_Unit
)) = E_Package_Body
384 and then Is_Generic_Unit
(Spec_Entity
(Cunit_Entity
(Main_Unit
)))
389 -- Only unnest when generating code for the main source unit
391 if not In_Extended_Main_Code_Unit
(Subp_Body
) then
395 -- This routine is called late, after the scope stack is gone. The
396 -- following creates a suitable dummy scope stack to be used for the
397 -- analyze/expand calls made from this routine.
401 -- First step, we must mark all nested subprograms that require a static
402 -- link (activation record) because either they contain explicit uplevel
403 -- references (as indicated by Is_Uplevel_Referenced_Entity being set at
404 -- this point), or they make calls to other subprograms in the same nest
405 -- that require a static link (in which case we set this flag).
407 -- This is a recursive definition, and to implement this, we have to
408 -- build a call graph for the set of nested subprograms, and then go
409 -- over this graph to implement recursively the invariant that if a
410 -- subprogram has a call to a subprogram requiring a static link, then
411 -- the calling subprogram requires a static link.
413 -- First populate the above tables
415 Subps_First
:= Subps
.Last
+ 1;
419 Build_Tables
: declare
420 Current_Subprogram
: Entity_Id
;
421 -- When we scan a subprogram body, we set Current_Subprogram to the
422 -- corresponding entity. This gets recursively saved and restored.
424 function Visit_Node
(N
: Node_Id
) return Traverse_Result
;
425 -- Visit a single node in Subp
431 procedure Visit
is new Traverse_Proc
(Visit_Node
);
432 -- Used to traverse the body of Subp, populating the tables
438 function Visit_Node
(N
: Node_Id
) return Traverse_Result
is
443 procedure Check_Static_Type
444 (T
: Entity_Id
; N
: Node_Id
; DT
: in out Boolean);
445 -- Given a type T, checks if it is a static type defined as a type
446 -- with no dynamic bounds in sight. If so, the only action is to
447 -- set Is_Static_Type True for T. If T is not a static type, then
448 -- all types with dynamic bounds associated with T are detected,
449 -- and their bounds are marked as uplevel referenced if not at the
450 -- library level, and DT is set True. If N is specified, it's the
451 -- node that will need to be replaced. If not specified, it means
452 -- we can't do a replacement because the bound is implicit.
454 procedure Note_Uplevel_Ref
459 -- Called when we detect an explicit or implicit uplevel reference
460 -- from within Caller to entity E declared in Callee. E can be a
461 -- an object or a type.
463 procedure Register_Subprogram
(E
: Entity_Id
; Bod
: Node_Id
);
464 -- Enter a subprogram whose body is visible or which is a
465 -- subprogram instance into the subprogram table.
467 -----------------------
468 -- Check_Static_Type --
469 -----------------------
471 procedure Check_Static_Type
472 (T
: Entity_Id
; N
: Node_Id
; DT
: in out Boolean)
474 procedure Note_Uplevel_Bound
(N
: Node_Id
; Ref
: Node_Id
);
475 -- N is the bound of a dynamic type. This procedure notes that
476 -- this bound is uplevel referenced, it can handle references
477 -- to entities (typically _FIRST and _LAST entities), and also
478 -- attribute references of the form T'name (name is typically
479 -- FIRST or LAST) where T is the uplevel referenced bound.
480 -- Ref, if Present, is the location of the reference to
483 ------------------------
484 -- Note_Uplevel_Bound --
485 ------------------------
487 procedure Note_Uplevel_Bound
(N
: Node_Id
; Ref
: Node_Id
) is
489 -- Entity name case. Make sure that the entity is declared
490 -- in a subprogram. This may not be the case for for a type
491 -- in a loop appearing in a precondition.
492 -- Exclude explicitly discriminants (that can appear
493 -- in bounds of discriminated components).
495 if Is_Entity_Name
(N
) then
496 if Present
(Entity
(N
))
497 and then Present
(Enclosing_Subprogram
(Entity
(N
)))
498 and then Ekind
(Entity
(N
)) /= E_Discriminant
503 Caller
=> Current_Subprogram
,
504 Callee
=> Enclosing_Subprogram
(Entity
(N
)));
507 -- Attribute or indexed component case
509 elsif Nkind_In
(N
, N_Attribute_Reference
,
512 Note_Uplevel_Bound
(Prefix
(N
), Ref
);
514 -- The indices of the indexed components, or the
515 -- associated expressions of an attribute reference,
516 -- may also involve uplevel references.
522 Expr
:= First
(Expressions
(N
));
523 while Present
(Expr
) loop
524 Note_Uplevel_Bound
(Expr
, Ref
);
529 -- Binary operator cases. These can apply to arrays for
530 -- which we may need bounds.
532 elsif Nkind
(N
) in N_Binary_Op
then
533 Note_Uplevel_Bound
(Left_Opnd
(N
), Ref
);
534 Note_Uplevel_Bound
(Right_Opnd
(N
), Ref
);
536 -- Unary operator case
538 elsif Nkind
(N
) in N_Unary_Op
then
539 Note_Uplevel_Bound
(Right_Opnd
(N
), Ref
);
541 -- Explicit dereference case
543 elsif Nkind
(N
) = N_Explicit_Dereference
then
544 Note_Uplevel_Bound
(Prefix
(N
), Ref
);
548 elsif Nkind
(N
) = N_Type_Conversion
then
549 Note_Uplevel_Bound
(Expression
(N
), Ref
);
551 end Note_Uplevel_Bound
;
553 -- Start of processing for Check_Static_Type
556 -- If already marked static, immediate return
558 if Is_Static_Type
(T
) then
562 -- If the type is at library level, always consider it static,
563 -- since such uplevel references are irrelevant.
565 if Is_Library_Level_Entity
(T
) then
566 Set_Is_Static_Type
(T
);
570 -- Otherwise figure out what the story is with this type
572 -- For a scalar type, check bounds
574 if Is_Scalar_Type
(T
) then
576 -- If both bounds static, then this is a static type
579 LB
: constant Node_Id
:= Type_Low_Bound
(T
);
580 UB
: constant Node_Id
:= Type_High_Bound
(T
);
583 if not Is_Static_Expression
(LB
) then
584 Note_Uplevel_Bound
(LB
, N
);
588 if not Is_Static_Expression
(UB
) then
589 Note_Uplevel_Bound
(UB
, N
);
594 -- For record type, check all components and discriminant
595 -- constraints if present.
597 elsif Is_Record_Type
(T
) then
603 C
:= First_Component_Or_Discriminant
(T
);
604 while Present
(C
) loop
605 Check_Static_Type
(Etype
(C
), N
, DT
);
606 Next_Component_Or_Discriminant
(C
);
609 if Has_Discriminants
(T
)
610 and then Present
(Discriminant_Constraint
(T
))
612 D
:= First_Elmt
(Discriminant_Constraint
(T
));
613 while Present
(D
) loop
614 if not Is_Static_Expression
(Node
(D
)) then
615 Note_Uplevel_Bound
(Node
(D
), N
);
624 -- For array type, check index types and component type
626 elsif Is_Array_Type
(T
) then
630 Check_Static_Type
(Component_Type
(T
), N
, DT
);
632 IX
:= First_Index
(T
);
633 while Present
(IX
) loop
634 Check_Static_Type
(Etype
(IX
), N
, DT
);
639 -- For private type, examine whether full view is static
641 elsif Is_Private_Type
(T
) and then Present
(Full_View
(T
)) then
642 Check_Static_Type
(Full_View
(T
), N
, DT
);
644 if Is_Static_Type
(Full_View
(T
)) then
645 Set_Is_Static_Type
(T
);
648 -- For now, ignore other types
655 Set_Is_Static_Type
(T
);
657 end Check_Static_Type
;
659 ----------------------
660 -- Note_Uplevel_Ref --
661 ----------------------
663 procedure Note_Uplevel_Ref
669 Full_E
: Entity_Id
:= E
;
671 -- Nothing to do for static type
673 if Is_Static_Type
(E
) then
677 -- Nothing to do if Caller and Callee are the same
679 if Caller
= Callee
then
682 -- Callee may be a function that returns an array, and that has
683 -- been rewritten as a procedure. If caller is that procedure,
684 -- nothing to do either.
686 elsif Ekind
(Callee
) = E_Function
687 and then Rewritten_For_C
(Callee
)
688 and then Corresponding_Procedure
(Callee
) = Caller
693 -- We have a new uplevel referenced entity
695 if Ekind
(E
) = E_Constant
and then Present
(Full_View
(E
)) then
696 Full_E
:= Full_View
(E
);
699 -- All we do at this stage is to add the uplevel reference to
700 -- the table. It's too early to do anything else, since this
701 -- uplevel reference may come from an unreachable subprogram
702 -- in which case the entry will be deleted.
704 Urefs
.Append
((N
, Full_E
, Caller
, Callee
));
705 end Note_Uplevel_Ref
;
707 -------------------------
708 -- Register_Subprogram --
709 -------------------------
711 procedure Register_Subprogram
(E
: Entity_Id
; Bod
: Node_Id
) is
712 L
: constant Nat
:= Get_Level
(Subp
, E
);
715 -- Subprograms declared in tasks and protected types cannot
716 -- be eliminated because calls to them may be in other units,
717 -- so they must be treated as reachable.
723 Reachable
=> In_Synchronized_Unit
(E
),
725 -- Subprograms declared in tasks and protected types are
726 -- reachable and cannot be eliminated.
729 Declares_AREC
=> False,
739 Set_Subps_Index
(E
, UI_From_Int
(Subps
.Last
));
740 end Register_Subprogram
;
742 -- Start of processing for Visit_Node
747 -- Record a subprogram call
750 | N_Procedure_Call_Statement
752 -- We are only interested in direct calls, not indirect
753 -- calls (where Name (N) is an explicit dereference) at
756 if Nkind
(Name
(N
)) in N_Has_Entity
then
757 Ent
:= Entity
(Name
(N
));
759 -- We are only interested in calls to subprograms nested
760 -- within Subp. Calls to Subp itself or to subprograms
761 -- outside the nested structure do not affect us.
763 if Scope_Within
(Ent
, Subp
)
764 and then Is_Subprogram
(Ent
)
765 and then not Is_Imported
(Ent
)
767 Append_Unique_Call
((N
, Current_Subprogram
, Ent
));
771 -- For all calls where the formal is an unconstrained array
772 -- and the actual is constrained we need to check the bounds
773 -- for uplevel references.
777 DT
: Boolean := False;
782 if Nkind
(Name
(N
)) = N_Explicit_Dereference
then
783 Subp
:= Etype
(Name
(N
));
785 Subp
:= Entity
(Name
(N
));
788 Actual
:= First_Actual
(N
);
789 Formal
:= First_Formal_With_Extras
(Subp
);
790 while Present
(Actual
) loop
791 if Is_Array_Type
(Etype
(Formal
))
792 and then not Is_Constrained
(Etype
(Formal
))
793 and then Is_Constrained
(Etype
(Actual
))
795 Check_Static_Type
(Etype
(Actual
), Empty
, DT
);
798 Next_Actual
(Actual
);
799 Next_Formal_With_Extras
(Formal
);
803 -- An At_End_Proc in a statement sequence indicates that there
804 -- is a call from the enclosing construct or block to that
805 -- subprogram. As above, the called entity must be local and
808 when N_Handled_Sequence_Of_Statements
=>
809 if Present
(At_End_Proc
(N
))
810 and then Scope_Within
(Entity
(At_End_Proc
(N
)), Subp
)
811 and then not Is_Imported
(Entity
(At_End_Proc
(N
)))
814 ((N
, Current_Subprogram
, Entity
(At_End_Proc
(N
))));
817 -- Similarly, the following constructs include a semantic
818 -- attribute Procedure_To_Call that must be handled like
819 -- other calls. Likewise for attribute Storage_Pool.
822 | N_Extended_Return_Statement
824 | N_Simple_Return_Statement
827 Pool
: constant Entity_Id
:= Storage_Pool
(N
);
828 Proc
: constant Entity_Id
:= Procedure_To_Call
(N
);
832 and then Scope_Within
(Proc
, Subp
)
833 and then not Is_Imported
(Proc
)
835 Append_Unique_Call
((N
, Current_Subprogram
, Proc
));
839 and then not Is_Library_Level_Entity
(Pool
)
840 and then Scope_Within_Or_Same
(Scope
(Pool
), Subp
)
842 Caller
:= Current_Subprogram
;
843 Callee
:= Enclosing_Subprogram
(Pool
);
845 if Callee
/= Caller
then
846 Note_Uplevel_Ref
(Pool
, Empty
, Caller
, Callee
);
851 -- For an allocator with a qualified expression, check type
852 -- of expression being qualified. The explicit type name is
853 -- handled as an entity reference.
855 if Nkind
(N
) = N_Allocator
856 and then Nkind
(Expression
(N
)) = N_Qualified_Expression
859 DT
: Boolean := False;
862 (Etype
(Expression
(Expression
(N
))), Empty
, DT
);
866 -- A 'Access reference is a (potential) call. So is 'Address,
867 -- in particular on imported subprograms. Other attributes
868 -- require special handling.
870 when N_Attribute_Reference
=>
872 Attr
: constant Attribute_Id
:=
873 Get_Attribute_Id
(Attribute_Name
(N
));
876 when Attribute_Access
877 | Attribute_Unchecked_Access
878 | Attribute_Unrestricted_Access
881 if Nkind
(Prefix
(N
)) in N_Has_Entity
then
882 Ent
:= Entity
(Prefix
(N
));
884 -- We only need to examine calls to subprograms
885 -- nested within current Subp.
887 if Scope_Within
(Ent
, Subp
) then
888 if Is_Imported
(Ent
) then
891 elsif Is_Subprogram
(Ent
) then
893 ((N
, Current_Subprogram
, Ent
));
898 -- References to bounds can be uplevel references if
899 -- the type isn't static.
905 -- Special-case attributes of objects whose bounds
906 -- may be uplevel references. More complex prefixes
907 -- handled during full traversal. Note that if the
908 -- nominal subtype of the prefix is unconstrained,
909 -- the bound must be obtained from the object, not
910 -- from the (possibly) uplevel reference.
912 if Is_Constrained
(Etype
(Prefix
(N
))) then
914 DT
: Boolean := False;
917 (Etype
(Prefix
(N
)), Empty
, DT
);
928 -- Component associations in aggregates are either static or
929 -- else the aggregate will be expanded into assignments, in
930 -- which case the expression is analyzed later and provides
931 -- no relevant code generation.
933 when N_Component_Association
=>
934 if No
(Expression
(N
))
935 or else No
(Etype
(Expression
(N
)))
940 -- Generic associations are not analyzed: the actuals are
941 -- transferred to renaming and subtype declarations that
942 -- are the ones that must be examined.
944 when N_Generic_Association
=>
947 -- Indexed references can be uplevel if the type isn't static
948 -- and if the lower bound (or an inner bound for a multi-
949 -- dimensional array) is uplevel.
951 when N_Indexed_Component
954 if Is_Constrained
(Etype
(Prefix
(N
))) then
956 DT
: Boolean := False;
958 Check_Static_Type
(Etype
(Prefix
(N
)), Empty
, DT
);
962 -- A selected component can have an implicit up-level
963 -- reference due to the bounds of previous fields in the
964 -- record. We simplify the processing here by examining
965 -- all components of the record.
967 -- Selected components appear as unit names and end labels
968 -- for child units. Prefixes of these nodes denote parent
969 -- units and carry no type information so they are skipped.
971 when N_Selected_Component
=>
972 if Present
(Etype
(Prefix
(N
))) then
974 DT
: Boolean := False;
976 Check_Static_Type
(Etype
(Prefix
(N
)), Empty
, DT
);
980 -- For EQ/NE comparisons, we need the type of the operands
981 -- in order to do the comparison, which means we need the
988 DT
: Boolean := False;
990 Check_Static_Type
(Etype
(Left_Opnd
(N
)), Empty
, DT
);
991 Check_Static_Type
(Etype
(Right_Opnd
(N
)), Empty
, DT
);
994 -- Likewise we need the sizes to compute how much to move in
997 when N_Assignment_Statement
=>
999 DT
: Boolean := False;
1001 Check_Static_Type
(Etype
(Name
(N
)), Empty
, DT
);
1002 Check_Static_Type
(Etype
(Expression
(N
)), Empty
, DT
);
1005 -- Record a subprogram. We record a subprogram body that acts
1006 -- as a spec. Otherwise we record a subprogram declaration,
1007 -- providing that it has a corresponding body we can get hold
1008 -- of. The case of no corresponding body being available is
1011 when N_Subprogram_Body
=>
1012 Ent
:= Unique_Defining_Entity
(N
);
1014 -- Ignore generic subprogram
1016 if Is_Generic_Subprogram
(Ent
) then
1020 -- Make new entry in subprogram table if not already made
1022 Register_Subprogram
(Ent
, N
);
1024 -- We make a recursive call to scan the subprogram body, so
1025 -- that we can save and restore Current_Subprogram.
1028 Save_CS
: constant Entity_Id
:= Current_Subprogram
;
1032 Current_Subprogram
:= Ent
;
1034 -- Scan declarations
1036 Decl
:= First
(Declarations
(N
));
1037 while Present
(Decl
) loop
1044 Visit
(Handled_Statement_Sequence
(N
));
1046 -- Restore current subprogram setting
1048 Current_Subprogram
:= Save_CS
;
1051 -- Now at this level, return skipping the subprogram body
1052 -- descendants, since we already took care of them!
1056 -- If we have a body stub, visit the associated subunit, which
1057 -- is a semantic descendant of the stub.
1060 Visit
(Library_Unit
(N
));
1062 -- A declaration of a wrapper package indicates a subprogram
1063 -- instance for which there is no explicit body. Enter the
1064 -- subprogram instance in the table.
1066 when N_Package_Declaration
=>
1067 if Is_Wrapper_Package
(Defining_Entity
(N
)) then
1069 (Related_Instance
(Defining_Entity
(N
)), Empty
);
1072 -- Skip generic declarations
1074 when N_Generic_Declaration
=>
1077 -- Skip generic package body
1079 when N_Package_Body
=>
1080 if Present
(Corresponding_Spec
(N
))
1081 and then Ekind
(Corresponding_Spec
(N
)) = E_Generic_Package
1086 -- Pragmas and component declarations can be ignored
1088 when N_Component_Declaration
1093 -- Otherwise record an uplevel reference in a local identifier
1096 if Nkind
(N
) in N_Has_Entity
1097 and then Present
(Entity
(N
))
1101 -- Only interested in entities declared within our nest
1103 if not Is_Library_Level_Entity
(Ent
)
1104 and then Scope_Within_Or_Same
(Scope
(Ent
), Subp
)
1106 -- Skip entities defined in inlined subprograms
1109 Chars
(Enclosing_Subprogram
(Ent
)) /= Name_uParent
1111 -- Constants and variables are potentially uplevel
1112 -- references to global declarations.
1115 (Ekind_In
(Ent
, E_Constant
,
1119 -- Formals are interesting, but not if being used
1120 -- as mere names of parameters for name notation
1126 (Nkind
(Parent
(N
)) = N_Parameter_Association
1127 and then Selector_Name
(Parent
(N
)) = N
))
1129 -- Types other than known Is_Static types are
1130 -- potentially interesting.
1133 (Is_Type
(Ent
) and then not Is_Static_Type
(Ent
)))
1135 -- Here we have a potentially interesting uplevel
1136 -- reference to examine.
1138 if Is_Type
(Ent
) then
1140 DT
: Boolean := False;
1143 Check_Static_Type
(Ent
, N
, DT
);
1145 if Is_Static_Type
(Ent
) then
1151 Caller
:= Current_Subprogram
;
1152 Callee
:= Enclosing_Subprogram
(Ent
);
1155 and then (not Is_Static_Type
(Ent
)
1156 or else Needs_Fat_Pointer
(Ent
))
1158 Note_Uplevel_Ref
(Ent
, N
, Caller
, Callee
);
1160 -- Check the type of a formal parameter of the current
1161 -- subprogram, whose formal type may be an uplevel
1164 elsif Is_Formal
(Ent
)
1165 and then Scope
(Ent
) = Current_Subprogram
1168 DT
: Boolean := False;
1171 Check_Static_Type
(Etype
(Ent
), Empty
, DT
);
1178 -- Fall through to continue scanning children of this node
1183 -- Start of processing for Build_Tables
1186 -- Traverse the body to get subprograms, calls and uplevel references
1191 -- Now do the first transitive closure which determines which
1192 -- subprograms in the nest are actually reachable.
1194 Reachable_Closure
: declare
1198 Subps
.Table
(Subps_First
).Reachable
:= True;
1200 -- We use a simple minded algorithm as follows (obviously this can
1201 -- be done more efficiently, using one of the standard algorithms
1202 -- for efficient transitive closure computation, but this is simple
1203 -- and most likely fast enough that its speed does not matter).
1205 -- Repeatedly scan the list of calls. Any time we find a call from
1206 -- A to B, where A is reachable, but B is not, then B is reachable,
1207 -- and note that we have made a change by setting Modified True. We
1208 -- repeat this until we make a pass with no modifications.
1212 Inner
: for J
in Calls
.First
.. Calls
.Last
loop
1214 CTJ
: Call_Entry
renames Calls
.Table
(J
);
1216 SINF
: constant SI_Type
:= Subp_Index
(CTJ
.Caller
);
1217 SINT
: constant SI_Type
:= Subp_Index
(CTJ
.Callee
);
1219 SUBF
: Subp_Entry
renames Subps
.Table
(SINF
);
1220 SUBT
: Subp_Entry
renames Subps
.Table
(SINT
);
1223 if SUBF
.Reachable
and then not SUBT
.Reachable
then
1224 SUBT
.Reachable
:= True;
1230 exit Outer
when not Modified
;
1232 end Reachable_Closure
;
1234 -- Remove calls from unreachable subprograms
1241 for J
in Calls
.First
.. Calls
.Last
loop
1243 CTJ
: Call_Entry
renames Calls
.Table
(J
);
1245 SINF
: constant SI_Type
:= Subp_Index
(CTJ
.Caller
);
1246 SINT
: constant SI_Type
:= Subp_Index
(CTJ
.Callee
);
1248 SUBF
: Subp_Entry
renames Subps
.Table
(SINF
);
1249 SUBT
: Subp_Entry
renames Subps
.Table
(SINT
);
1252 if SUBF
.Reachable
then
1253 pragma Assert
(SUBT
.Reachable
);
1254 New_Index
:= New_Index
+ 1;
1255 Calls
.Table
(New_Index
) := Calls
.Table
(J
);
1260 Calls
.Set_Last
(New_Index
);
1263 -- Remove uplevel references from unreachable subprograms
1270 for J
in Urefs
.First
.. Urefs
.Last
loop
1272 URJ
: Uref_Entry
renames Urefs
.Table
(J
);
1274 SINF
: constant SI_Type
:= Subp_Index
(URJ
.Caller
);
1275 SINT
: constant SI_Type
:= Subp_Index
(URJ
.Callee
);
1277 SUBF
: Subp_Entry
renames Subps
.Table
(SINF
);
1278 SUBT
: Subp_Entry
renames Subps
.Table
(SINT
);
1283 -- Keep reachable reference
1285 if SUBF
.Reachable
then
1286 New_Index
:= New_Index
+ 1;
1287 Urefs
.Table
(New_Index
) := Urefs
.Table
(J
);
1289 -- And since we know we are keeping this one, this is a good
1290 -- place to fill in information for a good reference.
1292 -- Mark all enclosing subprograms need to declare AREC
1296 S
:= Enclosing_Subprogram
(S
);
1298 -- If we are at the top level, as can happen with
1299 -- references to formals in aspects of nested subprogram
1300 -- declarations, there are no further subprograms to mark
1301 -- as requiring activation records.
1306 SUBI
: Subp_Entry
renames Subps
.Table
(Subp_Index
(S
));
1308 SUBI
.Declares_AREC
:= True;
1310 -- If this entity was marked reachable because it is
1311 -- in a task or protected type, there may not appear
1312 -- to be any calls to it, which would normally adjust
1313 -- the levels of the parent subprograms. So we need to
1314 -- be sure that the uplevel reference of that entity
1315 -- takes into account possible calls.
1317 if In_Synchronized_Unit
(SUBF
.Ent
)
1318 and then SUBT
.Lev
< SUBI
.Uplevel_Ref
1320 SUBI
.Uplevel_Ref
:= SUBT
.Lev
;
1324 exit when S
= URJ
.Callee
;
1327 -- Add to list of uplevel referenced entities for Callee.
1328 -- We do not add types to this list, only actual references
1329 -- to objects that will be referenced uplevel, and we use
1330 -- the flag Is_Uplevel_Referenced_Entity to avoid making
1331 -- duplicate entries in the list.
1332 -- Discriminants are also excluded, only the enclosing
1333 -- object can appear in the list.
1335 if not Is_Uplevel_Referenced_Entity
(URJ
.Ent
)
1336 and then Ekind
(URJ
.Ent
) /= E_Discriminant
1338 Set_Is_Uplevel_Referenced_Entity
(URJ
.Ent
);
1340 if not Is_Type
(URJ
.Ent
) then
1341 Append_New_Elmt
(URJ
.Ent
, SUBT
.Uents
);
1345 -- And set uplevel indication for caller
1347 if SUBT
.Lev
< SUBF
.Uplevel_Ref
then
1348 SUBF
.Uplevel_Ref
:= SUBT
.Lev
;
1354 Urefs
.Set_Last
(New_Index
);
1357 -- Remove unreachable subprograms from Subps table. Note that we do
1358 -- this after eliminating entries from the other two tables, since
1359 -- those elimination steps depend on referencing the Subps table.
1365 New_SI
:= Subps_First
- 1;
1366 for J
in Subps_First
.. Subps
.Last
loop
1368 STJ
: Subp_Entry
renames Subps
.Table
(J
);
1373 -- Subprogram is reachable, copy and reset index
1375 if STJ
.Reachable
then
1376 New_SI
:= New_SI
+ 1;
1377 Subps
.Table
(New_SI
) := STJ
;
1378 Set_Subps_Index
(STJ
.Ent
, UI_From_Int
(New_SI
));
1380 -- Subprogram is not reachable
1383 -- Clear index, since no longer active
1385 Set_Subps_Index
(Subps
.Table
(J
).Ent
, Uint_0
);
1387 -- Output debug information if -gnatd.3 set
1389 if Debug_Flag_Dot_3
then
1390 Write_Str
("Eliminate ");
1391 Write_Name
(Chars
(Subps
.Table
(J
).Ent
));
1393 Write_Location
(Sloc
(Subps
.Table
(J
).Ent
));
1394 Write_Str
(" (not referenced)");
1398 -- Rewrite declaration and body to null statements
1400 -- A subprogram instantiation does not have an explicit
1401 -- body. If unused, we could remove the corresponding
1402 -- wrapper package and its body (TBD).
1404 if Present
(STJ
.Bod
) then
1405 Spec
:= Corresponding_Spec
(STJ
.Bod
);
1407 if Present
(Spec
) then
1408 Decl
:= Parent
(Declaration_Node
(Spec
));
1409 Rewrite
(Decl
, Make_Null_Statement
(Sloc
(Decl
)));
1412 Rewrite
(STJ
.Bod
, Make_Null_Statement
(Sloc
(STJ
.Bod
)));
1418 Subps
.Set_Last
(New_SI
);
1421 -- Now it is time for the second transitive closure, which follows calls
1422 -- and makes sure that A calls B, and B has uplevel references, then A
1423 -- is also marked as having uplevel references.
1425 Closure_Uplevel
: declare
1429 -- We use a simple minded algorithm as follows (obviously this can
1430 -- be done more efficiently, using one of the standard algorithms
1431 -- for efficient transitive closure computation, but this is simple
1432 -- and most likely fast enough that its speed does not matter).
1434 -- Repeatedly scan the list of calls. Any time we find a call from
1435 -- A to B, where B has uplevel references, make sure that A is marked
1436 -- as having at least the same level of uplevel referencing.
1440 Inner2
: for J
in Calls
.First
.. Calls
.Last
loop
1442 CTJ
: Call_Entry
renames Calls
.Table
(J
);
1443 SINF
: constant SI_Type
:= Subp_Index
(CTJ
.Caller
);
1444 SINT
: constant SI_Type
:= Subp_Index
(CTJ
.Callee
);
1445 SUBF
: Subp_Entry
renames Subps
.Table
(SINF
);
1446 SUBT
: Subp_Entry
renames Subps
.Table
(SINT
);
1448 if SUBT
.Lev
> SUBT
.Uplevel_Ref
1449 and then SUBF
.Uplevel_Ref
> SUBT
.Uplevel_Ref
1451 SUBF
.Uplevel_Ref
:= SUBT
.Uplevel_Ref
;
1457 exit Outer2
when not Modified
;
1459 end Closure_Uplevel
;
1461 -- We have one more step before the tables are complete. An uplevel
1462 -- call from subprogram A to subprogram B where subprogram B has uplevel
1463 -- references is in effect an uplevel reference, and must arrange for
1464 -- the proper activation link to be passed.
1466 for J
in Calls
.First
.. Calls
.Last
loop
1468 CTJ
: Call_Entry
renames Calls
.Table
(J
);
1470 SINF
: constant SI_Type
:= Subp_Index
(CTJ
.Caller
);
1471 SINT
: constant SI_Type
:= Subp_Index
(CTJ
.Callee
);
1473 SUBF
: Subp_Entry
renames Subps
.Table
(SINF
);
1474 SUBT
: Subp_Entry
renames Subps
.Table
(SINT
);
1479 -- If callee has uplevel references
1481 if SUBT
.Uplevel_Ref
< SUBT
.Lev
1483 -- And this is an uplevel call
1485 and then SUBT
.Lev
< SUBF
.Lev
1487 -- We need to arrange for finding the uplink
1491 A
:= Enclosing_Subprogram
(A
);
1492 Subps
.Table
(Subp_Index
(A
)).Declares_AREC
:= True;
1493 exit when A
= CTJ
.Callee
;
1495 -- In any case exit when we get to the outer level. This
1496 -- happens in some odd cases with generics (in particular
1497 -- sem_ch3.adb does not compile without this kludge ???).
1505 -- The tables are now complete, so we can record the last index in the
1506 -- Subps table for later reference in Cprint.
1508 Subps
.Table
(Subps_First
).Last
:= Subps
.Last
;
1510 -- Next step, create the entities for code we will insert. We do this
1511 -- at the start so that all the entities are defined, regardless of the
1512 -- order in which we do the code insertions.
1514 Create_Entities
: for J
in Subps_First
.. Subps
.Last
loop
1516 STJ
: Subp_Entry
renames Subps
.Table
(J
);
1517 Loc
: constant Source_Ptr
:= Sloc
(STJ
.Bod
);
1520 -- First we create the ARECnF entity for the additional formal for
1521 -- all subprograms which need an activation record passed.
1523 if STJ
.Uplevel_Ref
< STJ
.Lev
then
1525 Make_Defining_Identifier
(Loc
, Chars
=> AREC_Name
(J
, "F"));
1528 -- Define the AREC entities for the activation record if needed
1530 if STJ
.Declares_AREC
then
1532 Make_Defining_Identifier
(Loc
, AREC_Name
(J
, ""));
1534 Make_Defining_Identifier
(Loc
, AREC_Name
(J
, "T"));
1536 Make_Defining_Identifier
(Loc
, AREC_Name
(J
, "PT"));
1538 Make_Defining_Identifier
(Loc
, AREC_Name
(J
, "P"));
1540 -- Define uplink component entity if inner nesting case
1542 if Present
(STJ
.ARECnF
) then
1544 Make_Defining_Identifier
(Loc
, AREC_Name
(J
, "U"));
1548 end loop Create_Entities
;
1550 -- Loop through subprograms
1553 Addr
: constant Entity_Id
:= RTE
(RE_Address
);
1556 for J
in Subps_First
.. Subps
.Last
loop
1558 STJ
: Subp_Entry
renames Subps
.Table
(J
);
1561 -- First add the extra formal if needed. This applies to all
1562 -- nested subprograms that require an activation record to be
1563 -- passed, as indicated by ARECnF being defined.
1565 if Present
(STJ
.ARECnF
) then
1567 -- Here we need the extra formal. We do the expansion and
1568 -- analysis of this manually, since it is fairly simple,
1569 -- and it is not obvious how we can get what we want if we
1570 -- try to use the normal Analyze circuit.
1572 Add_Extra_Formal
: declare
1573 Encl
: constant SI_Type
:= Enclosing_Subp
(J
);
1574 STJE
: Subp_Entry
renames Subps
.Table
(Encl
);
1575 -- Index and Subp_Entry for enclosing routine
1577 Form
: constant Entity_Id
:= STJ
.ARECnF
;
1578 -- The formal to be added. Note that n here is one less
1579 -- than the level of the subprogram itself (STJ.Ent).
1581 procedure Add_Form_To_Spec
(F
: Entity_Id
; S
: Node_Id
);
1582 -- S is an N_Function/Procedure_Specification node, and F
1583 -- is the new entity to add to this subprogramn spec as
1584 -- the last Extra_Formal.
1586 ----------------------
1587 -- Add_Form_To_Spec --
1588 ----------------------
1590 procedure Add_Form_To_Spec
(F
: Entity_Id
; S
: Node_Id
) is
1591 Sub
: constant Entity_Id
:= Defining_Entity
(S
);
1595 -- Case of at least one Extra_Formal is present, set
1596 -- ARECnF as the new last entry in the list.
1598 if Present
(Extra_Formals
(Sub
)) then
1599 Ent
:= Extra_Formals
(Sub
);
1600 while Present
(Extra_Formal
(Ent
)) loop
1601 Ent
:= Extra_Formal
(Ent
);
1604 Set_Extra_Formal
(Ent
, F
);
1606 -- No Extra formals present
1609 Set_Extra_Formals
(Sub
, F
);
1610 Ent
:= Last_Formal
(Sub
);
1612 if Present
(Ent
) then
1613 Set_Extra_Formal
(Ent
, F
);
1616 end Add_Form_To_Spec
;
1618 -- Start of processing for Add_Extra_Formal
1621 -- Decorate the new formal entity
1623 Set_Scope
(Form
, STJ
.Ent
);
1624 Set_Ekind
(Form
, E_In_Parameter
);
1625 Set_Etype
(Form
, STJE
.ARECnPT
);
1626 Set_Mechanism
(Form
, By_Copy
);
1627 Set_Never_Set_In_Source
(Form
, True);
1628 Set_Analyzed
(Form
, True);
1629 Set_Comes_From_Source
(Form
, False);
1630 Set_Is_Activation_Record
(Form
, True);
1632 -- Case of only body present
1634 if Acts_As_Spec
(STJ
.Bod
) then
1635 Add_Form_To_Spec
(Form
, Specification
(STJ
.Bod
));
1637 -- Case of separate spec
1640 Add_Form_To_Spec
(Form
, Parent
(STJ
.Ent
));
1642 end Add_Extra_Formal
;
1645 -- Processing for subprograms that declare an activation record
1647 if Present
(STJ
.ARECn
) then
1649 -- Local declarations for one such subprogram
1652 Loc
: constant Source_Ptr
:= Sloc
(STJ
.Bod
);
1654 Decls
: constant List_Id
:= New_List
;
1655 -- List of new declarations we create
1660 Decl_Assign
: Node_Id
;
1661 -- Assigment to set uplink, Empty if none
1663 Decl_ARECnT
: Node_Id
;
1664 Decl_ARECnPT
: Node_Id
;
1665 Decl_ARECn
: Node_Id
;
1666 Decl_ARECnP
: Node_Id
;
1667 -- Declaration nodes for the AREC entities we build
1670 -- Build list of component declarations for ARECnT
1672 Clist
:= Empty_List
;
1674 -- If we are in a subprogram that has a static link that
1675 -- is passed in (as indicated by ARECnF being defined),
1676 -- then include ARECnU : ARECmPT where ARECmPT comes from
1677 -- the level one higher than the current level, and the
1678 -- entity ARECnPT comes from the enclosing subprogram.
1680 if Present
(STJ
.ARECnF
) then
1683 renames Subps
.Table
(Enclosing_Subp
(J
));
1686 Make_Component_Declaration
(Loc
,
1687 Defining_Identifier
=> STJ
.ARECnU
,
1688 Component_Definition
=>
1689 Make_Component_Definition
(Loc
,
1690 Subtype_Indication
=>
1691 New_Occurrence_Of
(STJE
.ARECnPT
, Loc
))));
1695 -- Add components for uplevel referenced entities
1697 if Present
(STJ
.Uents
) then
1704 -- 1's origin of index in list of elements. This is
1705 -- used to uniquify names if needed in Upref_Name.
1708 Elmt
:= First_Elmt
(STJ
.Uents
);
1710 while Present
(Elmt
) loop
1711 Uent
:= Node
(Elmt
);
1715 Make_Defining_Identifier
(Loc
,
1716 Chars
=> Upref_Name
(Uent
, Indx
, Clist
));
1718 Set_Activation_Record_Component
1721 if Needs_Fat_Pointer
(Uent
) then
1723 -- Build corresponding access type
1726 Build_Access_Type_Decl
1727 (Etype
(Uent
), STJ
.Ent
);
1728 Append_To
(Decls
, Ptr_Decl
);
1730 -- And use its type in the corresponding
1734 Make_Component_Declaration
(Loc
,
1735 Defining_Identifier
=> Comp
,
1736 Component_Definition
=>
1737 Make_Component_Definition
(Loc
,
1738 Subtype_Indication
=>
1740 (Defining_Identifier
(Ptr_Decl
),
1744 Make_Component_Declaration
(Loc
,
1745 Defining_Identifier
=> Comp
,
1746 Component_Definition
=>
1747 Make_Component_Definition
(Loc
,
1748 Subtype_Indication
=>
1749 New_Occurrence_Of
(Addr
, Loc
))));
1756 -- Now we can insert the AREC declarations into the body
1757 -- type ARECnT is record .. end record;
1758 -- pragma Suppress_Initialization (ARECnT);
1760 -- Note that we need to set the Suppress_Initialization
1761 -- flag after Decl_ARECnT has been analyzed.
1764 Make_Full_Type_Declaration
(Loc
,
1765 Defining_Identifier
=> STJ
.ARECnT
,
1767 Make_Record_Definition
(Loc
,
1769 Make_Component_List
(Loc
,
1770 Component_Items
=> Clist
)));
1771 Append_To
(Decls
, Decl_ARECnT
);
1773 -- type ARECnPT is access all ARECnT;
1776 Make_Full_Type_Declaration
(Loc
,
1777 Defining_Identifier
=> STJ
.ARECnPT
,
1779 Make_Access_To_Object_Definition
(Loc
,
1780 All_Present
=> True,
1781 Subtype_Indication
=>
1782 New_Occurrence_Of
(STJ
.ARECnT
, Loc
)));
1783 Append_To
(Decls
, Decl_ARECnPT
);
1785 -- ARECn : aliased ARECnT;
1788 Make_Object_Declaration
(Loc
,
1789 Defining_Identifier
=> STJ
.ARECn
,
1790 Aliased_Present
=> True,
1791 Object_Definition
=>
1792 New_Occurrence_Of
(STJ
.ARECnT
, Loc
));
1793 Append_To
(Decls
, Decl_ARECn
);
1795 -- ARECnP : constant ARECnPT := ARECn'Access;
1798 Make_Object_Declaration
(Loc
,
1799 Defining_Identifier
=> STJ
.ARECnP
,
1800 Constant_Present
=> True,
1801 Object_Definition
=>
1802 New_Occurrence_Of
(STJ
.ARECnPT
, Loc
),
1804 Make_Attribute_Reference
(Loc
,
1806 New_Occurrence_Of
(STJ
.ARECn
, Loc
),
1807 Attribute_Name
=> Name_Access
));
1808 Append_To
(Decls
, Decl_ARECnP
);
1810 -- If we are in a subprogram that has a static link that
1811 -- is passed in (as indicated by ARECnF being defined),
1812 -- then generate ARECn.ARECmU := ARECmF where m is
1813 -- one less than the current level to set the uplink.
1815 if Present
(STJ
.ARECnF
) then
1817 Make_Assignment_Statement
(Loc
,
1819 Make_Selected_Component
(Loc
,
1821 New_Occurrence_Of
(STJ
.ARECn
, Loc
),
1823 New_Occurrence_Of
(STJ
.ARECnU
, Loc
)),
1825 New_Occurrence_Of
(STJ
.ARECnF
, Loc
));
1826 Append_To
(Decls
, Decl_Assign
);
1829 Decl_Assign
:= Empty
;
1832 Prepend_List_To
(Declarations
(STJ
.Bod
), Decls
);
1834 -- Analyze the newly inserted declarations. Note that we
1835 -- do not need to establish the whole scope stack, since
1836 -- we have already set all entity fields (so there will
1837 -- be no searching of upper scopes to resolve names). But
1838 -- we do set the scope of the current subprogram, so that
1839 -- newly created entities go in the right entity chain.
1841 -- We analyze with all checks suppressed (since we do
1842 -- not expect any exceptions).
1844 Push_Scope
(STJ
.Ent
);
1845 Analyze
(Decl_ARECnT
, Suppress
=> All_Checks
);
1847 -- Note that we need to call Set_Suppress_Initialization
1848 -- after Decl_ARECnT has been analyzed, but before
1849 -- analyzing Decl_ARECnP so that the flag is properly
1850 -- taking into account.
1852 Set_Suppress_Initialization
(STJ
.ARECnT
);
1854 Analyze
(Decl_ARECnPT
, Suppress
=> All_Checks
);
1855 Analyze
(Decl_ARECn
, Suppress
=> All_Checks
);
1856 Analyze
(Decl_ARECnP
, Suppress
=> All_Checks
);
1858 if Present
(Decl_Assign
) then
1859 Analyze
(Decl_Assign
, Suppress
=> All_Checks
);
1864 -- Next step, for each uplevel referenced entity, add
1865 -- assignment operations to set the component in the
1866 -- activation record.
1868 if Present
(STJ
.Uents
) then
1873 Elmt
:= First_Elmt
(STJ
.Uents
);
1874 while Present
(Elmt
) loop
1876 Ent
: constant Entity_Id
:= Node
(Elmt
);
1877 Loc
: constant Source_Ptr
:= Sloc
(Ent
);
1878 Dec
: constant Node_Id
:=
1879 Declaration_Node
(Ent
);
1886 -- For parameters, we insert the assignment
1887 -- right after the declaration of ARECnP.
1888 -- For all other entities, we insert the
1889 -- assignment immediately after the
1890 -- declaration of the entity or after the
1891 -- freeze node if present.
1893 -- Note: we don't need to mark the entity
1894 -- as being aliased, because the address
1895 -- attribute will mark it as Address_Taken,
1896 -- and that is good enough.
1898 if Is_Formal
(Ent
) then
1901 elsif Has_Delayed_Freeze
(Ent
) then
1902 Ins
:= Freeze_Node
(Ent
);
1908 -- Build and insert the assignment:
1909 -- ARECn.nam := nam'Address
1910 -- or else 'Access for unconstrained array
1912 if Needs_Fat_Pointer
(Ent
) then
1913 Attr
:= Name_Access
;
1915 Attr
:= Name_Address
;
1919 Make_Assignment_Statement
(Loc
,
1921 Make_Selected_Component
(Loc
,
1923 New_Occurrence_Of
(STJ
.ARECn
, Loc
),
1926 (Activation_Record_Component
1931 Make_Attribute_Reference
(Loc
,
1933 New_Occurrence_Of
(Ent
, Loc
),
1934 Attribute_Name
=> Attr
));
1936 -- If we have a loop parameter, we have
1937 -- to insert before the first statement
1938 -- of the loop. Ins points to the
1939 -- N_Loop_Parameter_Specification.
1941 if Ekind
(Ent
) = E_Loop_Parameter
then
1944 (Statements
(Parent
(Parent
(Ins
))));
1945 Insert_Before
(Ins
, Asn
);
1948 Insert_After
(Ins
, Asn
);
1951 -- Analyze the assignment statement. We do
1952 -- not need to establish the relevant scope
1953 -- stack entries here, because we have
1954 -- already set the correct entity references,
1955 -- so no name resolution is required, and no
1956 -- new entities are created, so we don't even
1957 -- need to set the current scope.
1959 -- We analyze with all checks suppressed
1960 -- (since we do not expect any exceptions).
1962 Analyze
(Asn
, Suppress
=> All_Checks
);
1975 -- Next step, process uplevel references. This has to be done in a
1976 -- separate pass, after completing the processing in Sub_Loop because we
1977 -- need all the AREC declarations generated, inserted, and analyzed so
1978 -- that the uplevel references can be successfully analyzed.
1980 Uplev_Refs
: for J
in Urefs
.First
.. Urefs
.Last
loop
1982 UPJ
: Uref_Entry
renames Urefs
.Table
(J
);
1985 -- Ignore type references, these are implicit references that do
1986 -- not need rewriting (e.g. the appearence in a conversion).
1987 -- Also ignore if no reference was specified or if the rewriting
1988 -- has already been done (this can happen if the N_Identifier
1989 -- occurs more than one time in the tree).
1990 -- Also ignore uplevel references to bounds of types that come
1991 -- from the original type reference.
1993 if Is_Type
(UPJ
.Ent
)
1994 or else No
(UPJ
.Ref
)
1995 or else not Is_Entity_Name
(UPJ
.Ref
)
1996 or else not Present
(Entity
(UPJ
.Ref
))
1997 or else Is_Type
(Entity
(UPJ
.Ref
))
2002 -- Also ignore uplevel references to bounds of types that come
2003 -- from the original type reference.
2005 if Is_Entity_Name
(UPJ
.Ref
)
2006 and then Present
(Entity
(UPJ
.Ref
))
2007 and then Is_Type
(Entity
(UPJ
.Ref
))
2012 -- Rewrite one reference
2014 Rewrite_One_Ref
: declare
2015 Loc
: constant Source_Ptr
:= Sloc
(UPJ
.Ref
);
2016 -- Source location for the reference
2018 Typ
: constant Entity_Id
:= Etype
(UPJ
.Ent
);
2019 -- The type of the referenced entity
2022 -- The actual subtype of the reference
2024 RS_Caller
: constant SI_Type
:= Subp_Index
(UPJ
.Caller
);
2025 -- Subp_Index for caller containing reference
2027 STJR
: Subp_Entry
renames Subps
.Table
(RS_Caller
);
2028 -- Subp_Entry for subprogram containing reference
2030 RS_Callee
: constant SI_Type
:= Subp_Index
(UPJ
.Callee
);
2031 -- Subp_Index for subprogram containing referenced entity
2033 STJE
: Subp_Entry
renames Subps
.Table
(RS_Callee
);
2034 -- Subp_Entry for subprogram containing referenced entity
2041 Atyp
:= Etype
(UPJ
.Ref
);
2043 if Ekind
(Atyp
) /= E_Record_Subtype
then
2044 Atyp
:= Get_Actual_Subtype
(UPJ
.Ref
);
2047 -- Ignore if no ARECnF entity for enclosing subprogram which
2048 -- probably happens as a result of not properly treating
2049 -- instance bodies. To be examined ???
2051 -- If this test is omitted, then the compilation of freeze.adb
2052 -- and inline.adb fail in unnesting mode.
2054 if No
(STJR
.ARECnF
) then
2058 -- Push the current scope, so that the pointer type Tnn, and
2059 -- any subsidiary entities resulting from the analysis of the
2060 -- rewritten reference, go in the right entity chain.
2062 Push_Scope
(STJR
.Ent
);
2064 -- Now we need to rewrite the reference. We have a reference
2065 -- from level STJR.Lev to level STJE.Lev. The general form of
2066 -- the rewritten reference for entity X is:
2068 -- Typ'Deref (ARECaF.ARECbU.ARECcU.ARECdU....ARECmU.X)
2070 -- where a,b,c,d .. m =
2071 -- STJR.Lev - 1, STJR.Lev - 2, .. STJE.Lev
2073 pragma Assert
(STJR
.Lev
> STJE
.Lev
);
2075 -- Compute the prefix of X. Here are examples to make things
2076 -- clear (with parens to show groupings, the prefix is
2077 -- everything except the .X at the end).
2079 -- level 2 to level 1
2083 -- level 3 to level 1
2085 -- (AREC2F.AREC1U).X
2087 -- level 4 to level 1
2089 -- ((AREC3F.AREC2U).AREC1U).X
2091 -- level 6 to level 2
2093 -- (((AREC5F.AREC4U).AREC3U).AREC2U).X
2095 -- In the above, ARECnF and ARECnU are pointers, so there are
2096 -- explicit dereferences required for these occurrences.
2099 Make_Explicit_Dereference
(Loc
,
2100 Prefix
=> New_Occurrence_Of
(STJR
.ARECnF
, Loc
));
2102 for L
in STJE
.Lev
.. STJR
.Lev
- 2 loop
2103 SI
:= Enclosing_Subp
(SI
);
2105 Make_Explicit_Dereference
(Loc
,
2107 Make_Selected_Component
(Loc
,
2110 New_Occurrence_Of
(Subps
.Table
(SI
).ARECnU
, Loc
)));
2113 -- Get activation record component (must exist)
2115 Comp
:= Activation_Record_Component
(UPJ
.Ent
);
2116 pragma Assert
(Present
(Comp
));
2118 -- Do the replacement. If the component type is an access type,
2119 -- this is an uplevel reference for an entity that requires a
2120 -- fat pointer, so dereference the component.
2122 if Is_Access_Type
(Etype
(Comp
)) then
2124 Make_Explicit_Dereference
(Loc
,
2126 Make_Selected_Component
(Loc
,
2129 New_Occurrence_Of
(Comp
, Loc
))));
2133 Make_Attribute_Reference
(Loc
,
2134 Prefix
=> New_Occurrence_Of
(Atyp
, Loc
),
2135 Attribute_Name
=> Name_Deref
,
2136 Expressions
=> New_List
(
2137 Make_Selected_Component
(Loc
,
2140 New_Occurrence_Of
(Comp
, Loc
)))));
2143 -- Analyze and resolve the new expression. We do not need to
2144 -- establish the relevant scope stack entries here, because we
2145 -- have already set all the correct entity references, so no
2146 -- name resolution is needed. We have already set the current
2147 -- scope, so that any new entities created will be in the right
2150 -- We analyze with all checks suppressed (since we do not
2151 -- expect any exceptions)
2153 Analyze_And_Resolve
(UPJ
.Ref
, Typ
, Suppress
=> All_Checks
);
2155 end Rewrite_One_Ref
;
2160 end loop Uplev_Refs
;
2162 -- Finally, loop through all calls adding extra actual for the
2163 -- activation record where it is required.
2165 Adjust_Calls
: for J
in Calls
.First
.. Calls
.Last
loop
2167 -- Process a single call, we are only interested in a call to a
2168 -- subprogram that actually needs a pointer to an activation record,
2169 -- as indicated by the ARECnF entity being set. This excludes the
2170 -- top level subprogram, and any subprogram not having uplevel refs.
2172 Adjust_One_Call
: declare
2173 CTJ
: Call_Entry
renames Calls
.Table
(J
);
2174 STF
: Subp_Entry
renames Subps
.Table
(Subp_Index
(CTJ
.Caller
));
2175 STT
: Subp_Entry
renames Subps
.Table
(Subp_Index
(CTJ
.Callee
));
2177 Loc
: constant Source_Ptr
:= Sloc
(CTJ
.N
);
2185 if Present
(STT
.ARECnF
)
2186 and then Nkind
(CTJ
.N
) in N_Subprogram_Call
2188 -- CTJ.N is a call to a subprogram which may require a pointer
2189 -- to an activation record. The subprogram containing the call
2190 -- is CTJ.From and the subprogram being called is CTJ.To, so we
2191 -- have a call from level STF.Lev to level STT.Lev.
2193 -- There are three possibilities:
2195 -- For a call to the same level, we just pass the activation
2196 -- record passed to the calling subprogram.
2198 if STF
.Lev
= STT
.Lev
then
2199 Extra
:= New_Occurrence_Of
(STF
.ARECnF
, Loc
);
2201 -- For a call that goes down a level, we pass a pointer to the
2202 -- activation record constructed within the caller (which may
2203 -- be the outer-level subprogram, but also may be a more deeply
2206 elsif STT
.Lev
= STF
.Lev
+ 1 then
2207 Extra
:= New_Occurrence_Of
(STF
.ARECnP
, Loc
);
2209 -- Otherwise we must have an upcall (STT.Lev < STF.LEV),
2210 -- since it is not possible to do a downcall of more than
2213 -- For a call from level STF.Lev to level STT.Lev, we
2214 -- have to find the activation record needed by the
2215 -- callee. This is as follows:
2217 -- ARECaF.ARECbU.ARECcU....ARECmU
2219 -- where a,b,c .. m =
2220 -- STF.Lev - 1, STF.Lev - 2, STF.Lev - 3 .. STT.Lev
2223 pragma Assert
(STT
.Lev
< STF
.Lev
);
2225 Extra
:= New_Occurrence_Of
(STF
.ARECnF
, Loc
);
2226 SubX
:= Subp_Index
(CTJ
.Caller
);
2227 for K
in reverse STT
.Lev
.. STF
.Lev
- 1 loop
2228 SubX
:= Enclosing_Subp
(SubX
);
2230 Make_Selected_Component
(Loc
,
2234 (Subps
.Table
(SubX
).ARECnU
, Loc
));
2238 -- Extra is the additional parameter to be added. Build a
2239 -- parameter association that we can append to the actuals.
2242 Make_Parameter_Association
(Loc
,
2244 New_Occurrence_Of
(STT
.ARECnF
, Loc
),
2245 Explicit_Actual_Parameter
=> Extra
);
2247 if No
(Parameter_Associations
(CTJ
.N
)) then
2248 Set_Parameter_Associations
(CTJ
.N
, Empty_List
);
2251 Append
(ExtraP
, Parameter_Associations
(CTJ
.N
));
2253 -- We need to deal with the actual parameter chain as well. The
2254 -- newly added parameter is always the last actual.
2256 Act
:= First_Named_Actual
(CTJ
.N
);
2259 Set_First_Named_Actual
(CTJ
.N
, Extra
);
2261 -- If call has been relocated (as with an expression in
2262 -- an aggregate), set First_Named pointer in original node
2263 -- as well, because that's the parent of the parameter list.
2265 Set_First_Named_Actual
2266 (Parent
(List_Containing
(ExtraP
)), Extra
);
2268 -- Here we must follow the chain and append the new entry
2277 PAN
:= Parent
(Act
);
2278 pragma Assert
(Nkind
(PAN
) = N_Parameter_Association
);
2279 NNA
:= Next_Named_Actual
(PAN
);
2282 Set_Next_Named_Actual
(PAN
, Extra
);
2291 -- Analyze and resolve the new actual. We do not need to
2292 -- establish the relevant scope stack entries here, because
2293 -- we have already set all the correct entity references, so
2294 -- no name resolution is needed.
2296 -- We analyze with all checks suppressed (since we do not
2297 -- expect any exceptions, and also we temporarily turn off
2298 -- Unested_Subprogram_Mode to avoid trying to mark uplevel
2299 -- references (not needed at this stage, and in fact causes
2300 -- a bit of recursive chaos).
2302 Opt
.Unnest_Subprogram_Mode
:= False;
2304 (Extra
, Etype
(STT
.ARECnF
), Suppress
=> All_Checks
);
2305 Opt
.Unnest_Subprogram_Mode
:= True;
2307 end Adjust_One_Call
;
2308 end loop Adjust_Calls
;
2311 end Unnest_Subprogram
;
2313 ------------------------
2314 -- Unnest_Subprograms --
2315 ------------------------
2317 procedure Unnest_Subprograms
(N
: Node_Id
) is
2318 function Search_Subprograms
(N
: Node_Id
) return Traverse_Result
;
2319 -- Tree visitor that search for outer level procedures with nested
2320 -- subprograms and invokes Unnest_Subprogram()
2326 procedure Do_Search
is new Traverse_Proc
(Search_Subprograms
);
2327 -- Subtree visitor instantiation
2329 ------------------------
2330 -- Search_Subprograms --
2331 ------------------------
2333 function Search_Subprograms
(N
: Node_Id
) return Traverse_Result
is
2335 if Nkind_In
(N
, N_Subprogram_Body
, N_Subprogram_Body_Stub
) then
2337 Spec_Id
: constant Entity_Id
:= Unique_Defining_Entity
(N
);
2340 -- We are only interested in subprograms (not generic
2341 -- subprograms), that have nested subprograms.
2343 if Is_Subprogram
(Spec_Id
)
2344 and then Has_Nested_Subprogram
(Spec_Id
)
2345 and then Is_Library_Level_Entity
(Spec_Id
)
2347 Unnest_Subprogram
(Spec_Id
, N
);
2352 -- The proper body of a stub may contain nested subprograms, and
2353 -- therefore must be visited explicitly. Nested stubs are examined
2354 -- recursively in Visit_Node.
2356 if Nkind
(N
) in N_Body_Stub
then
2357 Do_Search
(Library_Unit
(N
));
2361 end Search_Subprograms
;
2363 -- Start of processing for Unnest_Subprograms
2366 if not Opt
.Unnest_Subprogram_Mode
or not Opt
.Expander_Active
then
2370 -- A specification will contain bodies if it contains instantiations so
2371 -- examine package or subprogram declaration of the main unit, when it
2374 if Nkind
(Unit
(N
)) = N_Package_Body
2375 or else (Nkind
(Unit
(N
)) = N_Subprogram_Body
2376 and then not Acts_As_Spec
(N
))
2378 Do_Search
(Library_Unit
(N
));
2382 end Unnest_Subprograms
;