1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                             S E M _ E L A B                              --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 1997-2013, Free Software Foundation, Inc.         --
10--                                                                          --
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.          --
20--                                                                          --
21-- GNAT was originally developed  by the GNAT team at  New York University. --
22-- Extensive contributions were provided by Ada Core Technologies Inc.      --
23--                                                                          --
24------------------------------------------------------------------------------
25
26with Atree;    use Atree;
27with Checks;   use Checks;
28with Debug;    use Debug;
29with Einfo;    use Einfo;
30with Elists;   use Elists;
31with Errout;   use Errout;
32with Exp_Tss;  use Exp_Tss;
33with Exp_Util; use Exp_Util;
34with Expander; use Expander;
35with Fname;    use Fname;
36with Lib;      use Lib;
37with Lib.Load; use Lib.Load;
38with Namet;    use Namet;
39with Nlists;   use Nlists;
40with Nmake;    use Nmake;
41with Opt;      use Opt;
42with Output;   use Output;
43with Restrict; use Restrict;
44with Rident;   use Rident;
45with Sem;      use Sem;
46with Sem_Aux;  use Sem_Aux;
47with Sem_Cat;  use Sem_Cat;
48with Sem_Ch7;  use Sem_Ch7;
49with Sem_Ch8;  use Sem_Ch8;
50with Sem_Util; use Sem_Util;
51with Sinfo;    use Sinfo;
52with Sinput;   use Sinput;
53with Snames;   use Snames;
54with Stand;    use Stand;
55with Table;
56with Tbuild;   use Tbuild;
57with Uintp;    use Uintp;
58with Uname;    use Uname;
59
60package body Sem_Elab is
61
62   --  The following table records the recursive call chain for output in the
63   --  Output routine. Each entry records the call node and the entity of the
64   --  called routine. The number of entries in the table (i.e. the value of
65   --  Elab_Call.Last) indicates the current depth of recursion and is used to
66   --  identify the outer level.
67
68   type Elab_Call_Entry is record
69      Cloc : Source_Ptr;
70      Ent  : Entity_Id;
71   end record;
72
73   package Elab_Call is new Table.Table (
74     Table_Component_Type => Elab_Call_Entry,
75     Table_Index_Type     => Int,
76     Table_Low_Bound      => 1,
77     Table_Initial        => 50,
78     Table_Increment      => 100,
79     Table_Name           => "Elab_Call");
80
81   --  This table is initialized at the start of each outer level call. It
82   --  holds the entities for all subprograms that have been examined for this
83   --  particular outer level call, and is used to prevent both infinite
84   --  recursion, and useless reanalysis of bodies already seen
85
86   package Elab_Visited is new Table.Table (
87     Table_Component_Type => Entity_Id,
88     Table_Index_Type     => Int,
89     Table_Low_Bound      => 1,
90     Table_Initial        => 200,
91     Table_Increment      => 100,
92     Table_Name           => "Elab_Visited");
93
94   --  This table stores calls to Check_Internal_Call that are delayed
95   --  until all generics are instantiated, and in particular that all
96   --  generic bodies have been inserted. We need to delay, because we
97   --  need to be able to look through the inserted bodies.
98
99   type Delay_Element is record
100      N : Node_Id;
101      --  The parameter N from the call to Check_Internal_Call. Note that
102      --  this node may get rewritten over the delay period by expansion
103      --  in the call case (but not in the instantiation case).
104
105      E : Entity_Id;
106      --  The parameter E from the call to Check_Internal_Call
107
108      Orig_Ent : Entity_Id;
109      --  The parameter Orig_Ent from the call to Check_Internal_Call
110
111      Curscop : Entity_Id;
112      --  The current scope of the call. This is restored when we complete
113      --  the delayed call, so that we do this in the right scope.
114
115      From_Elab_Code : Boolean;
116      --  Save indication of whether this call is from elaboration code
117
118      Outer_Scope : Entity_Id;
119      --  Save scope of outer level call
120   end record;
121
122   package Delay_Check is new Table.Table (
123     Table_Component_Type => Delay_Element,
124     Table_Index_Type     => Int,
125     Table_Low_Bound      => 1,
126     Table_Initial        => 1000,
127     Table_Increment      => 100,
128     Table_Name           => "Delay_Check");
129
130   C_Scope : Entity_Id;
131   --  Top level scope of current scope. Compute this only once at the outer
132   --  level, i.e. for a call to Check_Elab_Call from outside this unit.
133
134   Outer_Level_Sloc : Source_Ptr;
135   --  Save Sloc value for outer level call node for comparisons of source
136   --  locations. A body is too late if it appears after the *outer* level
137   --  call, not the particular call that is being analyzed.
138
139   From_Elab_Code : Boolean;
140   --  This flag shows whether the outer level call currently being examined
141   --  is or is not in elaboration code. We are only interested in calls to
142   --  routines in other units if this flag is True.
143
144   In_Task_Activation : Boolean := False;
145   --  This flag indicates whether we are performing elaboration checks on
146   --  task procedures, at the point of activation. If true, we do not trace
147   --  internal calls in these procedures, because all local bodies are known
148   --  to be elaborated.
149
150   Delaying_Elab_Checks : Boolean := True;
151   --  This is set True till the compilation is complete, including the
152   --  insertion of all instance bodies. Then when Check_Elab_Calls is called,
153   --  the delay table is used to make the delayed calls and this flag is reset
154   --  to False, so that the calls are processed.
155
156   -----------------------
157   -- Local Subprograms --
158   -----------------------
159
160   --  Note: Outer_Scope in all following specs represents the scope of
161   --  interest of the outer level call. If it is set to Standard_Standard,
162   --  then it means the outer level call was at elaboration level, and that
163   --  thus all calls are of interest. If it was set to some other scope,
164   --  then the original call was an inner call, and we are not interested
165   --  in calls that go outside this scope.
166
167   procedure Activate_Elaborate_All_Desirable (N : Node_Id; U : Entity_Id);
168   --  Analysis of construct N shows that we should set Elaborate_All_Desirable
169   --  for the WITH clause for unit U (which will always be present). A special
170   --  case is when N is a function or procedure instantiation, in which case
171   --  it is sufficient to set Elaborate_Desirable, since in this case there is
172   --  no possibility of transitive elaboration issues.
173
174   procedure Check_A_Call
175     (N                 : Node_Id;
176      E                 : Entity_Id;
177      Outer_Scope       : Entity_Id;
178      Inter_Unit_Only   : Boolean;
179      Generate_Warnings : Boolean := True;
180      In_Init_Proc      : Boolean := False);
181   --  This is the internal recursive routine that is called to check for
182   --  possible elaboration error. The argument N is a subprogram call or
183   --  generic instantiation, or 'Access attribute reference to be checked, and
184   --  E is the entity of the called subprogram, or instantiated generic unit,
185   --  or subprogram referenced by 'Access.
186   --
187   --  The flag Outer_Scope is the outer level scope for the original call.
188   --  Inter_Unit_Only is set if the call is only to be checked in the
189   --  case where it is to another unit (and skipped if within a unit).
190   --  Generate_Warnings is set to False to suppress warning messages about
191   --  missing pragma Elaborate_All's. These messages are not wanted for
192   --  inner calls in the dynamic model. Note that an instance of the Access
193   --  attribute applied to a subprogram also generates a call to this
194   --  procedure (since the referenced subprogram may be called later
195   --  indirectly). Flag In_Init_Proc should be set whenever the current
196   --  context is a type init proc.
197
198   procedure Check_Bad_Instantiation (N : Node_Id);
199   --  N is a node for an instantiation (if called with any other node kind,
200   --  Check_Bad_Instantiation ignores the call). This subprogram checks for
201   --  the special case of a generic instantiation of a generic spec in the
202   --  same declarative part as the instantiation where a body is present and
203   --  has not yet been seen. This is an obvious error, but needs to be checked
204   --  specially at the time of the instantiation, since it is a case where we
205   --  cannot insert the body anywhere. If this case is detected, warnings are
206   --  generated, and a raise of Program_Error is inserted. In addition any
207   --  subprograms in the generic spec are stubbed, and the Bad_Instantiation
208   --  flag is set on the instantiation node. The caller in Sem_Ch12 uses this
209   --  flag as an indication that no attempt should be made to insert an
210   --  instance body.
211
212   procedure Check_Internal_Call
213     (N           : Node_Id;
214      E           : Entity_Id;
215      Outer_Scope : Entity_Id;
216      Orig_Ent    : Entity_Id);
217   --  N is a function call or procedure statement call node and E is the
218   --  entity of the called function, which is within the current compilation
219   --  unit (where subunits count as part of the parent). This call checks if
220   --  this call, or any call within any accessed body could cause an ABE, and
221   --  if so, outputs a warning. Orig_Ent differs from E only in the case of
222   --  renamings, and points to the original name of the entity. This is used
223   --  for error messages. Outer_Scope is the outer level scope for the
224   --  original call.
225
226   procedure Check_Internal_Call_Continue
227     (N           : Node_Id;
228      E           : Entity_Id;
229      Outer_Scope : Entity_Id;
230      Orig_Ent    : Entity_Id);
231   --  The processing for Check_Internal_Call is divided up into two phases,
232   --  and this represents the second phase. The second phase is delayed if
233   --  Delaying_Elab_Calls is set to True. In this delayed case, the first
234   --  phase makes an entry in the Delay_Check table, which is processed when
235   --  Check_Elab_Calls is called. N, E and Orig_Ent are as for the call to
236   --  Check_Internal_Call. Outer_Scope is the outer level scope for the
237   --  original call.
238
239   function Has_Generic_Body (N : Node_Id) return Boolean;
240   --  N is a generic package instantiation node, and this routine determines
241   --  if this package spec does in fact have a generic body. If so, then
242   --  True is returned, otherwise False. Note that this is not at all the
243   --  same as checking if the unit requires a body, since it deals with
244   --  the case of optional bodies accurately (i.e. if a body is optional,
245   --  then it looks to see if a body is actually present). Note: this
246   --  function can only do a fully correct job if in generating code mode
247   --  where all bodies have to be present. If we are operating in semantics
248   --  check only mode, then in some cases of optional bodies, a result of
249   --  False may incorrectly be given. In practice this simply means that
250   --  some cases of warnings for incorrect order of elaboration will only
251   --  be given when generating code, which is not a big problem (and is
252   --  inevitable, given the optional body semantics of Ada).
253
254   procedure Insert_Elab_Check (N : Node_Id; C : Node_Id := Empty);
255   --  Given code for an elaboration check (or unconditional raise if the check
256   --  is not needed), inserts the code in the appropriate place. N is the call
257   --  or instantiation node for which the check code is required. C is the
258   --  test whose failure triggers the raise.
259
260   function Is_Finalization_Procedure (Id : Entity_Id) return Boolean;
261   --  Determine whether entity Id denotes a [Deep_]Finalize procedure
262
263   procedure Output_Calls (N : Node_Id);
264   --  Outputs chain of calls stored in the Elab_Call table. The caller has
265   --  already generated the main warning message, so the warnings generated
266   --  are all continuation messages. The argument is the call node at which
267   --  the messages are to be placed.
268
269   function Same_Elaboration_Scope (Scop1, Scop2 : Entity_Id) return Boolean;
270   --  Given two scopes, determine whether they are the same scope from an
271   --  elaboration point of view, i.e. packages and blocks are ignored.
272
273   procedure Set_C_Scope;
274   --  On entry C_Scope is set to some scope. On return, C_Scope is reset
275   --  to be the enclosing compilation unit of this scope.
276
277   function Get_Referenced_Ent (N : Node_Id) return Entity_Id;
278   --  N is either a function or procedure call or an access attribute that
279   --  references a subprogram. This call retrieves the relevant entity. If
280   --  this is a call to a protected subprogram, the entity is a selected
281   --  component. The callable entity may be absent, in which case Empty is
282   --  returned. This happens with non-analyzed calls in nested generics.
283
284   procedure Set_Elaboration_Constraint
285    (Call : Node_Id;
286     Subp : Entity_Id;
287     Scop : Entity_Id);
288   --  The current unit U may depend semantically on some unit P which is not
289   --  in the current context. If there is an elaboration call that reaches P,
290   --  we need to indicate that P requires an Elaborate_All, but this is not
291   --  effective in U's ali file, if there is no with_clause for P. In this
292   --  case we add the Elaborate_All on the unit Q that directly or indirectly
293   --  makes P available. This can happen in two cases:
294   --
295   --    a) Q declares a subtype of a type declared in P, and the call is an
296   --    initialization call for an object of that subtype.
297   --
298   --    b) Q declares an object of some tagged type whose root type is
299   --    declared in P, and the initialization call uses object notation on
300   --    that object to reach a primitive operation or a classwide operation
301   --    declared in P.
302   --
303   --  If P appears in the context of U, the current processing is correct.
304   --  Otherwise we must identify these two cases to retrieve Q and place the
305   --  Elaborate_All_Desirable on it.
306
307   function Spec_Entity (E : Entity_Id) return Entity_Id;
308   --  Given a compilation unit entity, if it is a spec entity, it is returned
309   --  unchanged. If it is a body entity, then the spec for the corresponding
310   --  spec is returned
311
312   procedure Supply_Bodies (N : Node_Id);
313   --  Given a node, N, that is either a subprogram declaration or a package
314   --  declaration, this procedure supplies dummy bodies for the subprogram
315   --  or for all subprograms in the package. If the given node is not one
316   --  of these two possibilities, then Supply_Bodies does nothing. The
317   --  dummy body contains a single Raise statement.
318
319   procedure Supply_Bodies (L : List_Id);
320   --  Calls Supply_Bodies for all elements of the given list L
321
322   function Within (E1, E2 : Entity_Id) return Boolean;
323   --  Given two scopes E1 and E2, returns True if E1 is equal to E2, or is one
324   --  of its contained scopes, False otherwise.
325
326   function Within_Elaborate_All
327     (Unit : Unit_Number_Type;
328      E    : Entity_Id) return Boolean;
329   --  Return True if we are within the scope of an Elaborate_All for E, or if
330   --  we are within the scope of an Elaborate_All for some other unit U, and U
331   --  with's E. This prevents spurious warnings when the called entity is
332   --  renamed within U, or in case of generic instances.
333
334   --------------------------------------
335   -- Activate_Elaborate_All_Desirable --
336   --------------------------------------
337
338   procedure Activate_Elaborate_All_Desirable (N : Node_Id; U : Entity_Id) is
339      UN  : constant Unit_Number_Type := Get_Code_Unit (N);
340      CU  : constant Node_Id          := Cunit (UN);
341      UE  : constant Entity_Id        := Cunit_Entity (UN);
342      Unm : constant Unit_Name_Type   := Unit_Name (UN);
343      CI  : constant List_Id          := Context_Items (CU);
344      Itm : Node_Id;
345      Ent : Entity_Id;
346
347      procedure Add_To_Context_And_Mark (Itm : Node_Id);
348      --  This procedure is called when the elaborate indication must be
349      --  applied to a unit not in the context of the referencing unit. The
350      --  unit gets added to the context as an implicit with.
351
352      function In_Withs_Of (UEs : Entity_Id) return Boolean;
353      --  UEs is the spec entity of a unit. If the unit to be marked is
354      --  in the context item list of this unit spec, then the call returns
355      --  True and Itm is left set to point to the relevant N_With_Clause node.
356
357      procedure Set_Elab_Flag (Itm : Node_Id);
358      --  Sets Elaborate_[All_]Desirable as appropriate on Itm
359
360      -----------------------------
361      -- Add_To_Context_And_Mark --
362      -----------------------------
363
364      procedure Add_To_Context_And_Mark (Itm : Node_Id) is
365         CW : constant Node_Id :=
366                Make_With_Clause (Sloc (Itm),
367                  Name => Name (Itm));
368
369      begin
370         Set_Library_Unit  (CW, Library_Unit (Itm));
371         Set_Implicit_With (CW, True);
372
373         --  Set elaborate all desirable on copy and then append the copy to
374         --  the list of body with's and we are done.
375
376         Set_Elab_Flag (CW);
377         Append_To (CI, CW);
378      end Add_To_Context_And_Mark;
379
380      -----------------
381      -- In_Withs_Of --
382      -----------------
383
384      function In_Withs_Of (UEs : Entity_Id) return Boolean is
385         UNs : constant Unit_Number_Type := Get_Source_Unit (UEs);
386         CUs : constant Node_Id          := Cunit (UNs);
387         CIs : constant List_Id          := Context_Items (CUs);
388
389      begin
390         Itm := First (CIs);
391         while Present (Itm) loop
392            if Nkind (Itm) = N_With_Clause then
393               Ent :=
394                 Cunit_Entity (Get_Cunit_Unit_Number (Library_Unit (Itm)));
395
396               if U = Ent then
397                  return True;
398               end if;
399            end if;
400
401            Next (Itm);
402         end loop;
403
404         return False;
405      end In_Withs_Of;
406
407      -------------------
408      -- Set_Elab_Flag --
409      -------------------
410
411      procedure Set_Elab_Flag (Itm : Node_Id) is
412      begin
413         if Nkind (N) in N_Subprogram_Instantiation then
414            Set_Elaborate_Desirable (Itm);
415         else
416            Set_Elaborate_All_Desirable (Itm);
417         end if;
418      end Set_Elab_Flag;
419
420   --  Start of processing for Activate_Elaborate_All_Desirable
421
422   begin
423      --  Do not set binder indication if expansion is disabled, as when
424      --  compiling a generic unit.
425
426      if not Expander_Active then
427         return;
428      end if;
429
430      Itm := First (CI);
431      while Present (Itm) loop
432         if Nkind (Itm) = N_With_Clause then
433            Ent := Cunit_Entity (Get_Cunit_Unit_Number (Library_Unit (Itm)));
434
435            --  If we find it, then mark elaborate all desirable and return
436
437            if U = Ent then
438               Set_Elab_Flag (Itm);
439               return;
440            end if;
441         end if;
442
443         Next (Itm);
444      end loop;
445
446      --  If we fall through then the with clause is not present in the
447      --  current unit. One legitimate possibility is that the with clause
448      --  is present in the spec when we are a body.
449
450      if Is_Body_Name (Unm)
451        and then In_Withs_Of (Spec_Entity (UE))
452      then
453         Add_To_Context_And_Mark (Itm);
454         return;
455      end if;
456
457      --  Similarly, we may be in the spec or body of a child unit, where
458      --  the unit in question is with'ed by some ancestor of the child unit.
459
460      if Is_Child_Name (Unm) then
461         declare
462            Pkg : Entity_Id;
463
464         begin
465            Pkg := UE;
466            loop
467               Pkg := Scope (Pkg);
468               exit when Pkg = Standard_Standard;
469
470               if In_Withs_Of (Pkg) then
471                  Add_To_Context_And_Mark (Itm);
472                  return;
473               end if;
474            end loop;
475         end;
476      end if;
477
478      --  Here if we do not find with clause on spec or body. We just ignore
479      --  this case, it means that the elaboration involves some other unit
480      --  than the unit being compiled, and will be caught elsewhere.
481
482      null;
483   end Activate_Elaborate_All_Desirable;
484
485   ------------------
486   -- Check_A_Call --
487   ------------------
488
489   procedure Check_A_Call
490     (N                 : Node_Id;
491      E                 : Entity_Id;
492      Outer_Scope       : Entity_Id;
493      Inter_Unit_Only   : Boolean;
494      Generate_Warnings : Boolean := True;
495      In_Init_Proc      : Boolean := False)
496   is
497      Loc  : constant Source_Ptr := Sloc (N);
498      Ent  : Entity_Id;
499      Decl : Node_Id;
500
501      E_Scope : Entity_Id;
502      --  Top level scope of entity for called subprogram. This value includes
503      --  following renamings and derivations, so this scope can be in a
504      --  non-visible unit. This is the scope that is to be investigated to
505      --  see whether an elaboration check is required.
506
507      W_Scope : Entity_Id;
508      --  Top level scope of directly called entity for subprogram. This
509      --  differs from E_Scope in the case where renamings or derivations
510      --  are involved, since it does not follow these links. W_Scope is
511      --  generally in a visible unit, and it is this scope that may require
512      --  an Elaborate_All. However, there are some cases (initialization
513      --  calls and calls involving object notation) where W_Scope might not
514      --  be in the context of the current unit, and there is an intermediate
515      --  package that is, in which case the Elaborate_All has to be placed
516      --  on this intermediate package. These special cases are handled in
517      --  Set_Elaboration_Constraint.
518
519      Body_Acts_As_Spec : Boolean;
520      --  Set to true if call is to body acting as spec (no separate spec)
521
522      Inst_Case : constant Boolean := Nkind (N) in N_Generic_Instantiation;
523      --  Indicates if we have instantiation case
524
525      Access_Case : constant Boolean := Nkind (N) = N_Attribute_Reference;
526      --  Indicates if we have Access attribute case
527
528      Caller_Unit_Internal : Boolean;
529      Callee_Unit_Internal : Boolean;
530
531      Inst_Caller : Source_Ptr;
532      Inst_Callee : Source_Ptr;
533
534      Unit_Caller : Unit_Number_Type;
535      Unit_Callee : Unit_Number_Type;
536
537      Cunit_SC : Boolean := False;
538      --  Set to suppress dynamic elaboration checks where one of the
539      --  enclosing scopes has Elaboration_Checks_Suppressed set, or else
540      --  if a pragma Elaborate (_All) applies to that scope, in which case
541      --  warnings on the scope are also suppressed. For the internal case,
542      --  we ignore this flag.
543
544   begin
545      --  If the call is known to be within a local Suppress Elaboration
546      --  pragma, nothing to check. This can happen in task bodies.
547
548      if Nkind (N) in N_Subprogram_Call
549        and then No_Elaboration_Check (N)
550      then
551         return;
552      end if;
553
554      --  Go to parent for derived subprogram, or to original subprogram in the
555      --  case of a renaming (Alias covers both these cases).
556
557      Ent := E;
558      loop
559         if (Suppress_Elaboration_Warnings (Ent)
560              or else Elaboration_Checks_Suppressed (Ent))
561           and then (Inst_Case or else No (Alias (Ent)))
562         then
563            return;
564         end if;
565
566         --  Nothing to do for imported entities
567
568         if Is_Imported (Ent) then
569            return;
570         end if;
571
572         exit when Inst_Case or else No (Alias (Ent));
573         Ent := Alias (Ent);
574      end loop;
575
576      Decl := Unit_Declaration_Node (Ent);
577
578      if Nkind (Decl) = N_Subprogram_Body then
579         Body_Acts_As_Spec := True;
580
581      elsif Nkind (Decl) = N_Subprogram_Declaration
582        or else Nkind (Decl) = N_Subprogram_Body_Stub
583        or else Inst_Case
584      then
585         Body_Acts_As_Spec := False;
586
587      --  If we have none of an instantiation, subprogram body or
588      --  subprogram declaration, then it is not a case that we want
589      --  to check. (One case is a call to a generic formal subprogram,
590      --  where we do not want the check in the template).
591
592      else
593         return;
594      end if;
595
596      E_Scope := Ent;
597      loop
598         if Elaboration_Checks_Suppressed (E_Scope)
599           or else Suppress_Elaboration_Warnings (E_Scope)
600         then
601            Cunit_SC := True;
602         end if;
603
604         --  Exit when we get to compilation unit, not counting subunits
605
606         exit when Is_Compilation_Unit (E_Scope)
607           and then (Is_Child_Unit (E_Scope)
608                       or else Scope (E_Scope) = Standard_Standard);
609
610         --  If we did not find a compilation unit, other than standard,
611         --  then nothing to check (happens in some instantiation cases)
612
613         if E_Scope = Standard_Standard then
614            return;
615
616         --  Otherwise move up a scope looking for compilation unit
617
618         else
619            E_Scope := Scope (E_Scope);
620         end if;
621      end loop;
622
623      --  No checks needed for pure or preelaborated compilation units
624
625      if Is_Pure (E_Scope) or else Is_Preelaborated (E_Scope) then
626         return;
627      end if;
628
629      --  If the generic entity is within a deeper instance than we are, then
630      --  either the instantiation to which we refer itself caused an ABE, in
631      --  which case that will be handled separately, or else we know that the
632      --  body we need appears as needed at the point of the instantiation.
633      --  However, this assumption is only valid if we are in static mode.
634
635      if not Dynamic_Elaboration_Checks
636        and then Instantiation_Depth (Sloc (Ent)) >
637                 Instantiation_Depth (Sloc (N))
638      then
639         return;
640      end if;
641
642      --  Do not give a warning for a package with no body
643
644      if Ekind (Ent) = E_Generic_Package
645        and then not Has_Generic_Body (N)
646      then
647         return;
648      end if;
649
650      --  Case of entity is not in current unit (i.e. with'ed unit case)
651
652      if E_Scope /= C_Scope then
653
654         --  We are only interested in such calls if the outer call was from
655         --  elaboration code, or if we are in Dynamic_Elaboration_Checks mode.
656
657         if not From_Elab_Code and then not Dynamic_Elaboration_Checks then
658            return;
659         end if;
660
661         --  Nothing to do if some scope said that no checks were required
662
663         if Cunit_SC then
664            return;
665         end if;
666
667         --  Nothing to do for a generic instance, because in this case the
668         --  checking was at the point of instantiation of the generic However,
669         --  this shortcut is only applicable in static mode.
670
671         if Is_Generic_Instance (Ent) and not Dynamic_Elaboration_Checks then
672            return;
673         end if;
674
675         --  Nothing to do if subprogram with no separate spec. However, a
676         --  call to Deep_Initialize may result in a call to a user-defined
677         --  Initialize procedure, which imposes a body dependency. This
678         --  happens only if the type is controlled and the Initialize
679         --  procedure is not inherited.
680
681         if Body_Acts_As_Spec then
682            if Is_TSS (Ent, TSS_Deep_Initialize) then
683               declare
684                  Typ  : constant Entity_Id := Etype (First_Formal (Ent));
685                  Init : Entity_Id;
686
687               begin
688                  if not Is_Controlled (Typ) then
689                     return;
690                  else
691                     Init := Find_Prim_Op (Typ, Name_Initialize);
692
693                     if Comes_From_Source (Init) then
694                        Ent := Init;
695                     else
696                        return;
697                     end if;
698                  end if;
699               end;
700
701            else
702               return;
703            end if;
704         end if;
705
706         --  Check cases of internal units
707
708         Callee_Unit_Internal :=
709           Is_Internal_File_Name
710             (Unit_File_Name (Get_Source_Unit (E_Scope)));
711
712         --  Do not give a warning if the with'ed unit is internal and this is
713         --  the generic instantiation case (this saves a lot of hassle dealing
714         --  with the Text_IO special child units)
715
716         if Callee_Unit_Internal and Inst_Case then
717            return;
718         end if;
719
720         if C_Scope = Standard_Standard then
721            Caller_Unit_Internal := False;
722         else
723            Caller_Unit_Internal :=
724              Is_Internal_File_Name
725                (Unit_File_Name (Get_Source_Unit (C_Scope)));
726         end if;
727
728         --  Do not give a warning if the with'ed unit is internal and the
729         --  caller is not internal (since the binder always elaborates
730         --  internal units first).
731
732         if Callee_Unit_Internal and (not Caller_Unit_Internal) then
733            return;
734         end if;
735
736         --  For now, if debug flag -gnatdE is not set, do no checking for
737         --  one internal unit withing another. This fixes the problem with
738         --  the sgi build and storage errors. To be resolved later ???
739
740         if (Callee_Unit_Internal and Caller_Unit_Internal)
741            and then not Debug_Flag_EE
742         then
743            return;
744         end if;
745
746         if Is_TSS (E, TSS_Deep_Initialize) then
747            Ent := E;
748         end if;
749
750         --  If the call is in an instance, and the called entity is not
751         --  defined in the same instance, then the elaboration issue focuses
752         --  around the unit containing the template, it is this unit which
753         --  requires an Elaborate_All.
754
755         --  However, if we are doing dynamic elaboration, we need to chase the
756         --  call in the usual manner.
757
758         --  We do not handle the case of calling a generic formal correctly in
759         --  the static case.???
760
761         Inst_Caller := Instantiation (Get_Source_File_Index (Sloc (N)));
762         Inst_Callee := Instantiation (Get_Source_File_Index (Sloc (Ent)));
763
764         if Inst_Caller = No_Location then
765            Unit_Caller := No_Unit;
766         else
767            Unit_Caller := Get_Source_Unit (N);
768         end if;
769
770         if Inst_Callee = No_Location then
771            Unit_Callee := No_Unit;
772         else
773            Unit_Callee := Get_Source_Unit (Ent);
774         end if;
775
776         if Unit_Caller /= No_Unit
777           and then Unit_Callee /= Unit_Caller
778           and then not Dynamic_Elaboration_Checks
779         then
780            E_Scope := Spec_Entity (Cunit_Entity (Unit_Caller));
781
782            --  If we don't get a spec entity, just ignore call. Not quite
783            --  clear why this check is necessary. ???
784
785            if No (E_Scope) then
786               return;
787            end if;
788
789            --  Otherwise step to enclosing compilation unit
790
791            while not Is_Compilation_Unit (E_Scope) loop
792               E_Scope := Scope (E_Scope);
793            end loop;
794
795         --  For the case N is not an instance, or a call within instance, we
796         --  recompute E_Scope for the error message, since we do NOT want to
797         --  go to the unit which has the ultimate declaration in the case of
798         --  renaming and derivation and we also want to go to the generic unit
799         --  in the case of an instance, and no further.
800
801         else
802            --  Loop to carefully follow renamings and derivations one step
803            --  outside the current unit, but not further.
804
805            if not Inst_Case
806              and then Present (Alias (Ent))
807            then
808               E_Scope := Alias (Ent);
809            else
810               E_Scope := Ent;
811            end if;
812
813            loop
814               while not Is_Compilation_Unit (E_Scope) loop
815                  E_Scope := Scope (E_Scope);
816               end loop;
817
818               --  If E_Scope is the same as C_Scope, it means that there
819               --  definitely was a local renaming or derivation, and we
820               --  are not yet out of the current unit.
821
822               exit when E_Scope /= C_Scope;
823               Ent := Alias (Ent);
824               E_Scope := Ent;
825
826               --  If no alias, there is a previous error
827
828               if No (Ent) then
829                  Check_Error_Detected;
830                  return;
831               end if;
832            end loop;
833         end if;
834
835         if Within_Elaborate_All (Current_Sem_Unit, E_Scope) then
836            return;
837         end if;
838
839         --  Find top level scope for called entity (not following renamings
840         --  or derivations). This is where the Elaborate_All will go if it
841         --  is needed. We start with the called entity, except in the case
842         --  of an initialization procedure outside the current package, where
843         --  the init proc is in the root package, and we start from the entity
844         --  of the name in the call.
845
846         declare
847            Ent : constant Entity_Id := Get_Referenced_Ent (N);
848         begin
849            if Is_Init_Proc (Ent)
850              and then not In_Same_Extended_Unit (N, Ent)
851            then
852               W_Scope := Scope (Ent);
853            else
854               W_Scope := E;
855            end if;
856         end;
857
858         --  Now loop through scopes to get to the enclosing compilation unit
859
860         while not Is_Compilation_Unit (W_Scope) loop
861            W_Scope := Scope (W_Scope);
862         end loop;
863
864         --  Now check if an elaborate_all (or dynamic check) is needed
865
866         if not Suppress_Elaboration_Warnings (Ent)
867           and then not Elaboration_Checks_Suppressed (Ent)
868           and then not Suppress_Elaboration_Warnings (E_Scope)
869           and then not Elaboration_Checks_Suppressed (E_Scope)
870           and then (Elab_Warnings or Elab_Info_Messages)
871           and then Generate_Warnings
872         then
873            Generate_Elab_Warnings : declare
874               procedure Elab_Warning
875                 (Msg_D : String;
876                  Msg_S : String;
877                  Ent   : Node_Or_Entity_Id);
878               --  Generate a call to Error_Msg_NE with parameters Msg_D or
879               --  Msg_S (for dynamic or static elaboration model), N and Ent.
880               --  Msg_D is a real warning (output if Msg_D is non-null and
881               --  Elab_Warnings is set), Msg_S is an info message (output if
882               --  Elab_Info_Messages is set.
883
884               ------------------
885               -- Elab_Warning --
886               ------------------
887
888               procedure Elab_Warning
889                 (Msg_D : String;
890                  Msg_S : String;
891                  Ent   : Node_Or_Entity_Id)
892               is
893               begin
894                  --  Dynamic elaboration checks, real warning
895
896                  if Dynamic_Elaboration_Checks then
897                     if not Access_Case then
898                        if Msg_D /= "" and then Elab_Warnings then
899                           Error_Msg_NE (Msg_D, N, Ent);
900                        end if;
901                     end if;
902
903                  --  Static elaboration checks, info message
904
905                  else
906                     if Elab_Info_Messages then
907                        Error_Msg_NE (Msg_S, N, Ent);
908                     end if;
909                  end if;
910               end Elab_Warning;
911
912            --  Start of processing for Generate_Elab_Warnings
913
914            begin
915               --  Instantiation case
916
917               if Inst_Case then
918                  Elab_Warning
919                    ("instantiation of& may raise Program_Error?l?",
920                     "info: instantiation of& during elaboration?", Ent);
921
922               --  Indirect call case, info message only in static elaboration
923               --  case, because the attribute reference itself cannot raise
924               --  an exception.
925
926               elsif Access_Case then
927                  Elab_Warning
928                    ("", "info: access to& during elaboration?", Ent);
929
930               --  Subprogram call case
931
932               else
933                  if Nkind (Name (N)) in N_Has_Entity
934                    and then Is_Init_Proc (Entity (Name (N)))
935                    and then Comes_From_Source (Ent)
936                  then
937                     Elab_Warning
938                       ("implicit call to & may raise Program_Error?l?",
939                        "info: implicit call to & during elaboration?",
940                        Ent);
941
942                  else
943                     Elab_Warning
944                       ("call to & may raise Program_Error?l?",
945                        "info: call to & during elaboration?",
946                        Ent);
947                  end if;
948               end if;
949
950               Error_Msg_Qual_Level := Nat'Last;
951
952               if Nkind (N) in N_Subprogram_Instantiation then
953                  Elab_Warning
954                    ("\missing pragma Elaborate for&?l?",
955                     "\info: implicit pragma Elaborate for& generated?",
956                     W_Scope);
957
958               else
959                  Elab_Warning
960                    ("\missing pragma Elaborate_All for&?l?",
961                     "\info: implicit pragma Elaborate_All for & generated?",
962                     W_Scope);
963               end if;
964            end Generate_Elab_Warnings;
965
966            Error_Msg_Qual_Level := 0;
967            Output_Calls (N);
968
969            --  Set flag to prevent further warnings for same unit unless in
970            --  All_Errors_Mode.
971
972            if not All_Errors_Mode and not Dynamic_Elaboration_Checks then
973               Set_Suppress_Elaboration_Warnings (W_Scope, True);
974            end if;
975         end if;
976
977         --  Check for runtime elaboration check required
978
979         if Dynamic_Elaboration_Checks then
980            if not Elaboration_Checks_Suppressed (Ent)
981              and then not Elaboration_Checks_Suppressed (W_Scope)
982              and then not Elaboration_Checks_Suppressed (E_Scope)
983              and then not Cunit_SC
984            then
985               --  Runtime elaboration check required. Generate check of the
986               --  elaboration Boolean for the unit containing the entity.
987
988               --  Note that for this case, we do check the real unit (the one
989               --  from following renamings, since that is the issue).
990
991               --  Could this possibly miss a useless but required PE???
992
993               Insert_Elab_Check (N,
994                 Make_Attribute_Reference (Loc,
995                   Attribute_Name => Name_Elaborated,
996                   Prefix         =>
997                     New_Occurrence_Of (Spec_Entity (E_Scope), Loc)));
998
999               --  Prevent duplicate elaboration checks on the same call,
1000               --  which can happen if the body enclosing the call appears
1001               --  itself in a call whose elaboration check is delayed.
1002
1003               if Nkind (N) in N_Subprogram_Call then
1004                  Set_No_Elaboration_Check (N);
1005               end if;
1006            end if;
1007
1008         --  Case of static elaboration model
1009
1010         else
1011            --  Do not do anything if elaboration checks suppressed. Note that
1012            --  we check Ent here, not E, since we want the real entity for the
1013            --  body to see if checks are suppressed for it, not the dummy
1014            --  entry for renamings or derivations.
1015
1016            if Elaboration_Checks_Suppressed (Ent)
1017              or else Elaboration_Checks_Suppressed (E_Scope)
1018              or else Elaboration_Checks_Suppressed (W_Scope)
1019            then
1020               null;
1021
1022            --  Do not generate an Elaborate_All for finalization routines
1023            --  which perform partial clean up as part of initialization.
1024
1025            elsif In_Init_Proc and then Is_Finalization_Procedure (Ent) then
1026               null;
1027
1028            --  Here we need to generate an implicit elaborate all
1029
1030            else
1031               --  Generate Elaborate_all warning unless suppressed
1032
1033               if (Elab_Info_Messages and Generate_Warnings and not Inst_Case)
1034                 and then not Suppress_Elaboration_Warnings (Ent)
1035                 and then not Suppress_Elaboration_Warnings (E_Scope)
1036                 and then not Suppress_Elaboration_Warnings (W_Scope)
1037               then
1038                  Error_Msg_Node_2 := W_Scope;
1039                  Error_Msg_NE
1040                    ("info: call to& in elaboration code " &
1041                     "requires pragma Elaborate_All on&?", N, E);
1042               end if;
1043
1044               --  Set indication for binder to generate Elaborate_All
1045
1046               Set_Elaboration_Constraint (N, E, W_Scope);
1047            end if;
1048         end if;
1049
1050      --  Case of entity is in same unit as call or instantiation
1051
1052      elsif not Inter_Unit_Only then
1053         Check_Internal_Call (N, Ent, Outer_Scope, E);
1054      end if;
1055   end Check_A_Call;
1056
1057   -----------------------------
1058   -- Check_Bad_Instantiation --
1059   -----------------------------
1060
1061   procedure Check_Bad_Instantiation (N : Node_Id) is
1062      Ent : Entity_Id;
1063
1064   begin
1065      --  Nothing to do if we do not have an instantiation (happens in some
1066      --  error cases, and also in the formal package declaration case)
1067
1068      if Nkind (N) not in N_Generic_Instantiation then
1069         return;
1070
1071      --  Nothing to do if serious errors detected (avoid cascaded errors)
1072
1073      elsif Serious_Errors_Detected /= 0 then
1074         return;
1075
1076      --  Nothing to do if not in full analysis mode
1077
1078      elsif not Full_Analysis then
1079         return;
1080
1081      --  Nothing to do if inside a generic template
1082
1083      elsif Inside_A_Generic then
1084         return;
1085
1086      --  Nothing to do if a library level instantiation
1087
1088      elsif Nkind (Parent (N)) = N_Compilation_Unit then
1089         return;
1090
1091      --  Nothing to do if we are compiling a proper body for semantic
1092      --  purposes only. The generic body may be in another proper body.
1093
1094      elsif
1095        Nkind (Parent (Unit_Declaration_Node (Main_Unit_Entity))) = N_Subunit
1096      then
1097         return;
1098      end if;
1099
1100      Ent := Get_Generic_Entity (N);
1101
1102      --  The case we are interested in is when the generic spec is in the
1103      --  current declarative part
1104
1105      if not Same_Elaboration_Scope (Current_Scope, Scope (Ent))
1106        or else not In_Same_Extended_Unit (N, Ent)
1107      then
1108         return;
1109      end if;
1110
1111      --  If the generic entity is within a deeper instance than we are, then
1112      --  either the instantiation to which we refer itself caused an ABE, in
1113      --  which case that will be handled separately. Otherwise, we know that
1114      --  the body we need appears as needed at the point of the instantiation.
1115      --  If they are both at the same level but not within the same instance
1116      --  then the body of the generic will be in the earlier instance.
1117
1118      declare
1119         D1 : constant Int := Instantiation_Depth (Sloc (Ent));
1120         D2 : constant Int := Instantiation_Depth (Sloc (N));
1121
1122      begin
1123         if D1 > D2 then
1124            return;
1125
1126         elsif D1 = D2
1127           and then Is_Generic_Instance (Scope (Ent))
1128           and then not In_Open_Scopes (Scope (Ent))
1129         then
1130            return;
1131         end if;
1132      end;
1133
1134      --  Now we can proceed, if the entity being called has a completion,
1135      --  then we are definitely OK, since we have already seen the body.
1136
1137      if Has_Completion (Ent) then
1138         return;
1139      end if;
1140
1141      --  If there is no body, then nothing to do
1142
1143      if not Has_Generic_Body (N) then
1144         return;
1145      end if;
1146
1147      --  Here we definitely have a bad instantiation
1148
1149      Error_Msg_Warn := SPARK_Mode /= On;
1150      Error_Msg_NE ("cannot instantiate& before body seen<<", N, Ent);
1151
1152      if Present (Instance_Spec (N)) then
1153         Supply_Bodies (Instance_Spec (N));
1154      end if;
1155
1156      Error_Msg_N ("\Program_Error [<<", N);
1157      Insert_Elab_Check (N);
1158      Set_ABE_Is_Certain (N);
1159   end Check_Bad_Instantiation;
1160
1161   ---------------------
1162   -- Check_Elab_Call --
1163   ---------------------
1164
1165   procedure Check_Elab_Call
1166     (N            : Node_Id;
1167      Outer_Scope  : Entity_Id := Empty;
1168      In_Init_Proc : Boolean   := False)
1169   is
1170      Ent : Entity_Id;
1171      P   : Node_Id;
1172
1173   begin
1174      --  If the call does not come from the main unit, there is nothing to
1175      --  check. Elaboration call from units in the context of the main unit
1176      --  will lead to semantic dependencies when those units are compiled.
1177
1178      if not In_Extended_Main_Code_Unit (N) then
1179         return;
1180      end if;
1181
1182      --  For an entry call, check relevant restriction
1183
1184      if Nkind (N) = N_Entry_Call_Statement
1185         and then not In_Subprogram_Or_Concurrent_Unit
1186      then
1187         Check_Restriction (No_Entry_Calls_In_Elaboration_Code, N);
1188
1189      --  Nothing to do if this is not a call or attribute reference (happens
1190      --  in some error conditions, and in some cases where rewriting occurs).
1191
1192      elsif Nkind (N) not in N_Subprogram_Call
1193        and then Nkind (N) /= N_Attribute_Reference
1194      then
1195         return;
1196
1197      --  Nothing to do if this is a call already rewritten for elab checking
1198
1199      elsif Nkind (Parent (N)) = N_If_Expression then
1200         return;
1201
1202      --  Nothing to do if inside a generic template
1203
1204      elsif Inside_A_Generic
1205        and then No (Enclosing_Generic_Body (N))
1206      then
1207         return;
1208      end if;
1209
1210      --  Here we have a call at elaboration time which must be checked
1211
1212      if Debug_Flag_LL then
1213         Write_Str ("  Check_Elab_Call: ");
1214
1215         if Nkind (N) = N_Attribute_Reference then
1216            if not Is_Entity_Name (Prefix (N)) then
1217               Write_Str ("<<not entity name>>");
1218            else
1219               Write_Name (Chars (Entity (Prefix (N))));
1220            end if;
1221            Write_Str ("'Access");
1222
1223         elsif No (Name (N)) or else not Is_Entity_Name (Name (N)) then
1224            Write_Str ("<<not entity name>> ");
1225
1226         else
1227            Write_Name (Chars (Entity (Name (N))));
1228         end if;
1229
1230         Write_Str ("  call at ");
1231         Write_Location (Sloc (N));
1232         Write_Eol;
1233      end if;
1234
1235      --  Climb up the tree to make sure we are not inside default expression
1236      --  of a parameter specification or a record component, since in both
1237      --  these cases, we will be doing the actual call later, not now, and it
1238      --  is at the time of the actual call (statically speaking) that we must
1239      --  do our static check, not at the time of its initial analysis).
1240
1241      --  However, we have to check calls within component definitions (e.g.
1242      --  a function call that determines an array component bound), so we
1243      --  terminate the loop in that case.
1244
1245      P := Parent (N);
1246      while Present (P) loop
1247         if Nkind_In (P, N_Parameter_Specification,
1248                         N_Component_Declaration)
1249         then
1250            return;
1251
1252         --  The call occurs within the constraint of a component,
1253         --  so it must be checked.
1254
1255         elsif Nkind (P) = N_Component_Definition then
1256            exit;
1257
1258         else
1259            P := Parent (P);
1260         end if;
1261      end loop;
1262
1263      --  Stuff that happens only at the outer level
1264
1265      if No (Outer_Scope) then
1266         Elab_Visited.Set_Last (0);
1267
1268         --  Nothing to do if current scope is Standard (this is a bit odd, but
1269         --  it happens in the case of generic instantiations).
1270
1271         C_Scope := Current_Scope;
1272
1273         if C_Scope = Standard_Standard then
1274            return;
1275         end if;
1276
1277         --  First case, we are in elaboration code
1278
1279         From_Elab_Code := not In_Subprogram_Or_Concurrent_Unit;
1280         if From_Elab_Code then
1281
1282            --  Complain if call that comes from source in preelaborated unit
1283            --  and we are not inside a subprogram (i.e. we are in elab code).
1284
1285            if Comes_From_Source (N)
1286              and then In_Preelaborated_Unit
1287              and then not In_Inlined_Body
1288              and then Nkind (N) /= N_Attribute_Reference
1289            then
1290               --  This is a warning in GNAT mode allowing such calls to be
1291               --  used in the predefined library with appropriate care.
1292
1293               Error_Msg_Warn := GNAT_Mode;
1294               Error_Msg_N
1295                 ("<non-static call not allowed in preelaborated unit", N);
1296               return;
1297            end if;
1298
1299         --  Second case, we are inside a subprogram or concurrent unit, which
1300         --  means we are not in elaboration code.
1301
1302         else
1303            --  In this case, the issue is whether we are inside the
1304            --  declarative part of the unit in which we live, or inside its
1305            --  statements. In the latter case, there is no issue of ABE calls
1306            --  at this level (a call from outside to the unit in which we live
1307            --  might cause an ABE, but that will be detected when we analyze
1308            --  that outer level call, as it recurses into the called unit).
1309
1310            --  Climb up the tree, doing this test, and also testing for being
1311            --  inside a default expression, which, as discussed above, is not
1312            --  checked at this stage.
1313
1314            declare
1315               P : Node_Id;
1316               L : List_Id;
1317
1318            begin
1319               P := N;
1320               loop
1321                  --  If we find a parentless subtree, it seems safe to assume
1322                  --  that we are not in a declarative part and that no
1323                  --  checking is required.
1324
1325                  if No (P) then
1326                     return;
1327                  end if;
1328
1329                  if Is_List_Member (P) then
1330                     L := List_Containing (P);
1331                     P := Parent (L);
1332                  else
1333                     L := No_List;
1334                     P := Parent (P);
1335                  end if;
1336
1337                  exit when Nkind (P) = N_Subunit;
1338
1339                  --  Filter out case of default expressions, where we do not
1340                  --  do the check at this stage.
1341
1342                  if Nkind (P) = N_Parameter_Specification
1343                       or else
1344                     Nkind (P) = N_Component_Declaration
1345                  then
1346                     return;
1347                  end if;
1348
1349                  --  A protected body has no elaboration code and contains
1350                  --  only other bodies.
1351
1352                  if Nkind (P) = N_Protected_Body then
1353                     return;
1354
1355                  elsif Nkind (P) = N_Subprogram_Body
1356                       or else
1357                     Nkind (P) = N_Task_Body
1358                       or else
1359                     Nkind (P) = N_Block_Statement
1360                       or else
1361                     Nkind (P) = N_Entry_Body
1362                  then
1363                     if L = Declarations (P) then
1364                        exit;
1365
1366                     --  We are not in elaboration code, but we are doing
1367                     --  dynamic elaboration checks, in this case, we still
1368                     --  need to do the call, since the subprogram we are in
1369                     --  could be called from another unit, also in dynamic
1370                     --  elaboration check mode, at elaboration time.
1371
1372                     elsif Dynamic_Elaboration_Checks then
1373
1374                        --  We provide a debug flag to disable this check. That
1375                        --  way we have an easy work around for regressions
1376                        --  that are caused by this new check. This debug flag
1377                        --  can be removed later.
1378
1379                        if Debug_Flag_DD then
1380                           return;
1381                        end if;
1382
1383                        --  Do the check in this case
1384
1385                        exit;
1386
1387                     elsif Nkind (P) = N_Task_Body then
1388
1389                        --  The check is deferred until Check_Task_Activation
1390                        --  but we need to capture local suppress pragmas
1391                        --  that may inhibit checks on this call.
1392
1393                        Ent := Get_Referenced_Ent (N);
1394
1395                        if No (Ent) then
1396                           return;
1397
1398                        elsif Elaboration_Checks_Suppressed (Current_Scope)
1399                          or else Elaboration_Checks_Suppressed (Ent)
1400                          or else Elaboration_Checks_Suppressed (Scope (Ent))
1401                        then
1402                           Set_No_Elaboration_Check (N);
1403                        end if;
1404
1405                        return;
1406
1407                     --  Static model, call is not in elaboration code, we
1408                     --  never need to worry, because in the static model the
1409                     --  top level caller always takes care of things.
1410
1411                     else
1412                        return;
1413                     end if;
1414                  end if;
1415               end loop;
1416            end;
1417         end if;
1418      end if;
1419
1420      Ent := Get_Referenced_Ent (N);
1421
1422      if No (Ent) then
1423         return;
1424      end if;
1425
1426      --  Nothing to do if this is a recursive call (i.e. a call to
1427      --  an entity that is already in the Elab_Call stack)
1428
1429      for J in 1 .. Elab_Visited.Last loop
1430         if Ent = Elab_Visited.Table (J) then
1431            return;
1432         end if;
1433      end loop;
1434
1435      --  See if we need to analyze this call. We analyze it if either of
1436      --  the following conditions is met:
1437
1438      --    It is an inner level call (since in this case it was triggered
1439      --    by an outer level call from elaboration code), but only if the
1440      --    call is within the scope of the original outer level call.
1441
1442      --    It is an outer level call from elaboration code, or the called
1443      --    entity is in the same elaboration scope.
1444
1445      --  And in these cases, we will check both inter-unit calls and
1446      --  intra-unit (within a single unit) calls.
1447
1448      C_Scope := Current_Scope;
1449
1450      --  If not outer level call, then we follow it if it is within the
1451      --  original scope of the outer call.
1452
1453      if Present (Outer_Scope)
1454        and then Within (Scope (Ent), Outer_Scope)
1455      then
1456         Set_C_Scope;
1457         Check_A_Call
1458           (N               => N,
1459            E               => Ent,
1460            Outer_Scope     => Outer_Scope,
1461            Inter_Unit_Only => False,
1462            In_Init_Proc    => In_Init_Proc);
1463
1464      elsif Elaboration_Checks_Suppressed (Current_Scope) then
1465         null;
1466
1467      elsif From_Elab_Code then
1468         Set_C_Scope;
1469         Check_A_Call (N, Ent, Standard_Standard, Inter_Unit_Only => False);
1470
1471      elsif Same_Elaboration_Scope (C_Scope, Scope (Ent)) then
1472         Set_C_Scope;
1473         Check_A_Call (N, Ent, Scope (Ent), Inter_Unit_Only => False);
1474
1475      --  If none of those cases holds, but Dynamic_Elaboration_Checks mode
1476      --  is set, then we will do the check, but only in the inter-unit case
1477      --  (this is to accommodate unguarded elaboration calls from other units
1478      --  in which this same mode is set). We don't want warnings in this case,
1479      --  it would generate warnings having nothing to do with elaboration.
1480
1481      elsif Dynamic_Elaboration_Checks then
1482         Set_C_Scope;
1483         Check_A_Call
1484           (N,
1485            Ent,
1486            Standard_Standard,
1487            Inter_Unit_Only   => True,
1488            Generate_Warnings => False);
1489
1490      --  Otherwise nothing to do
1491
1492      else
1493         return;
1494      end if;
1495
1496      --  A call to an Init_Proc in elaboration code may bring additional
1497      --  dependencies, if some of the record components thereof have
1498      --  initializations that are function calls that come from source. We
1499      --  treat the current node as a call to each of these functions, to check
1500      --  their elaboration impact.
1501
1502      if Is_Init_Proc (Ent)
1503        and then From_Elab_Code
1504      then
1505         Process_Init_Proc : declare
1506            Unit_Decl : constant Node_Id := Unit_Declaration_Node (Ent);
1507
1508            function Check_Init_Call (Nod : Node_Id) return Traverse_Result;
1509            --  Find subprogram calls within body of Init_Proc for Traverse
1510            --  instantiation below.
1511
1512            procedure Traverse_Body is new Traverse_Proc (Check_Init_Call);
1513            --  Traversal procedure to find all calls with body of Init_Proc
1514
1515            ---------------------
1516            -- Check_Init_Call --
1517            ---------------------
1518
1519            function Check_Init_Call (Nod : Node_Id) return Traverse_Result is
1520               Func : Entity_Id;
1521
1522            begin
1523               if Nkind (Nod) in N_Subprogram_Call
1524                 and then Is_Entity_Name (Name (Nod))
1525               then
1526                  Func := Entity (Name (Nod));
1527
1528                  if Comes_From_Source (Func) then
1529                     Check_A_Call
1530                       (N, Func, Standard_Standard, Inter_Unit_Only => True);
1531                  end if;
1532
1533                  return OK;
1534
1535               else
1536                  return OK;
1537               end if;
1538            end Check_Init_Call;
1539
1540         --  Start of processing for Process_Init_Proc
1541
1542         begin
1543            if Nkind (Unit_Decl) = N_Subprogram_Body then
1544               Traverse_Body (Handled_Statement_Sequence (Unit_Decl));
1545            end if;
1546         end Process_Init_Proc;
1547      end if;
1548   end Check_Elab_Call;
1549
1550   -----------------------
1551   -- Check_Elab_Assign --
1552   -----------------------
1553
1554   procedure Check_Elab_Assign (N : Node_Id) is
1555      Ent  : Entity_Id;
1556      Scop : Entity_Id;
1557
1558      Pkg_Spec : Entity_Id;
1559      Pkg_Body : Entity_Id;
1560
1561   begin
1562      --  For record or array component, check prefix. If it is an access type,
1563      --  then there is nothing to do (we do not know what is being assigned),
1564      --  but otherwise this is an assignment to the prefix.
1565
1566      if Nkind_In (N, N_Indexed_Component,
1567                      N_Selected_Component,
1568                      N_Slice)
1569      then
1570         if not Is_Access_Type (Etype (Prefix (N))) then
1571            Check_Elab_Assign (Prefix (N));
1572         end if;
1573
1574         return;
1575      end if;
1576
1577      --  For type conversion, check expression
1578
1579      if Nkind (N) = N_Type_Conversion then
1580         Check_Elab_Assign (Expression (N));
1581         return;
1582      end if;
1583
1584      --  Nothing to do if this is not an entity reference otherwise get entity
1585
1586      if Is_Entity_Name (N) then
1587         Ent := Entity (N);
1588      else
1589         return;
1590      end if;
1591
1592      --  What we are looking for is a reference in the body of a package that
1593      --  modifies a variable declared in the visible part of the package spec.
1594
1595      if Present (Ent)
1596        and then Comes_From_Source (N)
1597        and then not Suppress_Elaboration_Warnings (Ent)
1598        and then Ekind (Ent) = E_Variable
1599        and then not In_Private_Part (Ent)
1600        and then Is_Library_Level_Entity (Ent)
1601      then
1602         Scop := Current_Scope;
1603         loop
1604            if No (Scop) or else Scop = Standard_Standard then
1605               return;
1606            elsif Ekind (Scop) = E_Package
1607              and then Is_Compilation_Unit (Scop)
1608            then
1609               exit;
1610            else
1611               Scop := Scope (Scop);
1612            end if;
1613         end loop;
1614
1615         --  Here Scop points to the containing library package
1616
1617         Pkg_Spec := Scop;
1618         Pkg_Body := Body_Entity (Pkg_Spec);
1619
1620         --  All OK if the package has an Elaborate_Body pragma
1621
1622         if Has_Pragma_Elaborate_Body (Scop) then
1623            return;
1624         end if;
1625
1626         --  OK if entity being modified is not in containing package spec
1627
1628         if not In_Same_Source_Unit (Scop, Ent) then
1629            return;
1630         end if;
1631
1632         --  All OK if entity appears in generic package or generic instance.
1633         --  We just get too messed up trying to give proper warnings in the
1634         --  presence of generics. Better no message than a junk one.
1635
1636         Scop := Scope (Ent);
1637         while Present (Scop) and then Scop /= Pkg_Spec loop
1638            if Ekind (Scop) = E_Generic_Package then
1639               return;
1640            elsif Ekind (Scop) = E_Package
1641              and then Is_Generic_Instance (Scop)
1642            then
1643               return;
1644            end if;
1645
1646            Scop := Scope (Scop);
1647         end loop;
1648
1649         --  All OK if in task, don't issue warnings there
1650
1651         if In_Task_Activation then
1652            return;
1653         end if;
1654
1655         --  OK if no package body
1656
1657         if No (Pkg_Body) then
1658            return;
1659         end if;
1660
1661         --  OK if reference is not in package body
1662
1663         if not In_Same_Source_Unit (Pkg_Body, N) then
1664            return;
1665         end if;
1666
1667         --  OK if package body has no handled statement sequence
1668
1669         declare
1670            HSS : constant Node_Id :=
1671                    Handled_Statement_Sequence (Declaration_Node (Pkg_Body));
1672         begin
1673            if No (HSS) or else not Comes_From_Source (HSS) then
1674               return;
1675            end if;
1676         end;
1677
1678         --  We definitely have a case of a modification of an entity in
1679         --  the package spec from the elaboration code of the package body.
1680         --  We may not give the warning (because there are some additional
1681         --  checks to avoid too many false positives), but it would be a good
1682         --  idea for the binder to try to keep the body elaboration close to
1683         --  the spec elaboration.
1684
1685         Set_Elaborate_Body_Desirable (Pkg_Spec);
1686
1687         --  All OK in gnat mode (we know what we are doing)
1688
1689         if GNAT_Mode then
1690            return;
1691         end if;
1692
1693         --  All OK if all warnings suppressed
1694
1695         if Warning_Mode = Suppress then
1696            return;
1697         end if;
1698
1699         --  All OK if elaboration checks suppressed for entity
1700
1701         if Checks_May_Be_Suppressed (Ent)
1702           and then Is_Check_Suppressed (Ent, Elaboration_Check)
1703         then
1704            return;
1705         end if;
1706
1707         --  OK if the entity is initialized. Note that the No_Initialization
1708         --  flag usually means that the initialization has been rewritten into
1709         --  assignments, but that still counts for us.
1710
1711         declare
1712            Decl : constant Node_Id := Declaration_Node (Ent);
1713         begin
1714            if Nkind (Decl) = N_Object_Declaration
1715              and then (Present (Expression (Decl))
1716                          or else No_Initialization (Decl))
1717            then
1718               return;
1719            end if;
1720         end;
1721
1722         --  Here is where we give the warning
1723
1724         --  All OK if warnings suppressed on the entity
1725
1726         if not Has_Warnings_Off (Ent) then
1727            Error_Msg_Sloc := Sloc (Ent);
1728
1729            Error_Msg_NE
1730              ("??& can be accessed by clients before this initialization",
1731               N, Ent);
1732            Error_Msg_NE
1733              ("\??add Elaborate_Body to spec to ensure & is initialized",
1734               N, Ent);
1735         end if;
1736
1737         if not All_Errors_Mode then
1738            Set_Suppress_Elaboration_Warnings (Ent);
1739         end if;
1740      end if;
1741   end Check_Elab_Assign;
1742
1743   ----------------------
1744   -- Check_Elab_Calls --
1745   ----------------------
1746
1747   procedure Check_Elab_Calls is
1748   begin
1749      --  If expansion is disabled, do not generate any checks. Also skip
1750      --  checks if any subunits are missing because in either case we lack the
1751      --  full information that we need, and no object file will be created in
1752      --  any case.
1753
1754      if not Expander_Active
1755        or else Is_Generic_Unit (Cunit_Entity (Main_Unit))
1756        or else Subunits_Missing
1757      then
1758         return;
1759      end if;
1760
1761      --  Skip delayed calls if we had any errors
1762
1763      if Serious_Errors_Detected = 0 then
1764         Delaying_Elab_Checks := False;
1765         Expander_Mode_Save_And_Set (True);
1766
1767         for J in Delay_Check.First .. Delay_Check.Last loop
1768            Push_Scope (Delay_Check.Table (J).Curscop);
1769            From_Elab_Code := Delay_Check.Table (J).From_Elab_Code;
1770
1771            Check_Internal_Call_Continue (
1772              N           => Delay_Check.Table (J).N,
1773              E           => Delay_Check.Table (J).E,
1774              Outer_Scope => Delay_Check.Table (J).Outer_Scope,
1775              Orig_Ent    => Delay_Check.Table (J).Orig_Ent);
1776
1777            Pop_Scope;
1778         end loop;
1779
1780         --  Set Delaying_Elab_Checks back on for next main compilation
1781
1782         Expander_Mode_Restore;
1783         Delaying_Elab_Checks := True;
1784      end if;
1785   end Check_Elab_Calls;
1786
1787   ------------------------------
1788   -- Check_Elab_Instantiation --
1789   ------------------------------
1790
1791   procedure Check_Elab_Instantiation
1792     (N           : Node_Id;
1793      Outer_Scope : Entity_Id := Empty)
1794   is
1795      Ent : Entity_Id;
1796
1797   begin
1798      --  Check for and deal with bad instantiation case. There is some
1799      --  duplicated code here, but we will worry about this later ???
1800
1801      Check_Bad_Instantiation (N);
1802
1803      if ABE_Is_Certain (N) then
1804         return;
1805      end if;
1806
1807      --  Nothing to do if we do not have an instantiation (happens in some
1808      --  error cases, and also in the formal package declaration case)
1809
1810      if Nkind (N) not in N_Generic_Instantiation then
1811         return;
1812      end if;
1813
1814      --  Nothing to do if inside a generic template
1815
1816      if Inside_A_Generic then
1817         return;
1818      end if;
1819
1820      --  Nothing to do if the instantiation is not in the main unit
1821
1822      if not In_Extended_Main_Code_Unit (N) then
1823         return;
1824      end if;
1825
1826      Ent := Get_Generic_Entity (N);
1827      From_Elab_Code := not In_Subprogram_Or_Concurrent_Unit;
1828
1829      --  See if we need to analyze this instantiation. We analyze it if
1830      --  either of the following conditions is met:
1831
1832      --    It is an inner level instantiation (since in this case it was
1833      --    triggered by an outer level call from elaboration code), but
1834      --    only if the instantiation is within the scope of the original
1835      --    outer level call.
1836
1837      --    It is an outer level instantiation from elaboration code, or the
1838      --    instantiated entity is in the same elaboration scope.
1839
1840      --  And in these cases, we will check both the inter-unit case and
1841      --  the intra-unit (within a single unit) case.
1842
1843      C_Scope := Current_Scope;
1844
1845      if Present (Outer_Scope)
1846        and then Within (Scope (Ent), Outer_Scope)
1847      then
1848         Set_C_Scope;
1849         Check_A_Call (N, Ent, Outer_Scope, Inter_Unit_Only => False);
1850
1851      elsif From_Elab_Code then
1852         Set_C_Scope;
1853         Check_A_Call (N, Ent, Standard_Standard, Inter_Unit_Only => False);
1854
1855      elsif Same_Elaboration_Scope (C_Scope, Scope (Ent)) then
1856         Set_C_Scope;
1857         Check_A_Call (N, Ent, Scope (Ent), Inter_Unit_Only => False);
1858
1859      --  If none of those cases holds, but Dynamic_Elaboration_Checks mode is
1860      --  set, then we will do the check, but only in the inter-unit case (this
1861      --  is to accommodate unguarded elaboration calls from other units in
1862      --  which this same mode is set). We inhibit warnings in this case, since
1863      --  this instantiation is not occurring in elaboration code.
1864
1865      elsif Dynamic_Elaboration_Checks then
1866         Set_C_Scope;
1867         Check_A_Call
1868           (N,
1869            Ent,
1870            Standard_Standard,
1871            Inter_Unit_Only => True,
1872            Generate_Warnings => False);
1873
1874      else
1875         return;
1876      end if;
1877   end Check_Elab_Instantiation;
1878
1879   -------------------------
1880   -- Check_Internal_Call --
1881   -------------------------
1882
1883   procedure Check_Internal_Call
1884     (N           : Node_Id;
1885      E           : Entity_Id;
1886      Outer_Scope : Entity_Id;
1887      Orig_Ent    : Entity_Id)
1888   is
1889      Inst_Case : constant Boolean := Nkind (N) in N_Generic_Instantiation;
1890
1891   begin
1892      --  If not function or procedure call or instantiation, then ignore
1893      --  call (this happens in some error cases and rewriting cases).
1894
1895      if not Nkind_In (N, N_Function_Call, N_Procedure_Call_Statement)
1896        and then not Inst_Case
1897      then
1898         return;
1899
1900      --  Nothing to do if this is a call or instantiation that has already
1901      --  been found to be a sure ABE.
1902
1903      elsif ABE_Is_Certain (N) then
1904         return;
1905
1906      --  Nothing to do if errors already detected (avoid cascaded errors)
1907
1908      elsif Serious_Errors_Detected /= 0 then
1909         return;
1910
1911      --  Nothing to do if not in full analysis mode
1912
1913      elsif not Full_Analysis then
1914         return;
1915
1916      --  Nothing to do if analyzing in special spec-expression mode, since the
1917      --  call is not actually being made at this time.
1918
1919      elsif In_Spec_Expression then
1920         return;
1921
1922      --  Nothing to do for call to intrinsic subprogram
1923
1924      elsif Is_Intrinsic_Subprogram (E) then
1925         return;
1926
1927      --  No need to trace local calls if checking task activation, because
1928      --  other local bodies are elaborated already.
1929
1930      elsif In_Task_Activation then
1931         return;
1932
1933      --  Nothing to do if call is within a generic unit
1934
1935      elsif Inside_A_Generic then
1936         return;
1937      end if;
1938
1939      --  Delay this call if we are still delaying calls
1940
1941      if Delaying_Elab_Checks then
1942         Delay_Check.Append (
1943           (N              => N,
1944            E              => E,
1945            Orig_Ent       => Orig_Ent,
1946            Curscop        => Current_Scope,
1947            Outer_Scope    => Outer_Scope,
1948            From_Elab_Code => From_Elab_Code));
1949         return;
1950
1951      --  Otherwise, call phase 2 continuation right now
1952
1953      else
1954         Check_Internal_Call_Continue (N, E, Outer_Scope, Orig_Ent);
1955      end if;
1956   end Check_Internal_Call;
1957
1958   ----------------------------------
1959   -- Check_Internal_Call_Continue --
1960   ----------------------------------
1961
1962   procedure Check_Internal_Call_Continue
1963     (N           : Node_Id;
1964      E           : Entity_Id;
1965      Outer_Scope : Entity_Id;
1966      Orig_Ent    : Entity_Id)
1967   is
1968      Loc       : constant Source_Ptr := Sloc (N);
1969      Inst_Case : constant Boolean := Is_Generic_Unit (E);
1970
1971      Sbody : Node_Id;
1972      Ebody : Entity_Id;
1973
1974      function Find_Elab_Reference (N : Node_Id) return Traverse_Result;
1975      --  Function applied to each node as we traverse the body. Checks for
1976      --  call or entity reference that needs checking, and if so checks it.
1977      --  Always returns OK, so entire tree is traversed, except that as
1978      --  described below subprogram bodies are skipped for now.
1979
1980      procedure Traverse is new Atree.Traverse_Proc (Find_Elab_Reference);
1981      --  Traverse procedure using above Find_Elab_Reference function
1982
1983      -------------------------
1984      -- Find_Elab_Reference --
1985      -------------------------
1986
1987      function Find_Elab_Reference (N : Node_Id) return Traverse_Result is
1988         Actual : Node_Id;
1989
1990      begin
1991         --  If user has specified that there are no entry calls in elaboration
1992         --  code, do not trace past an accept statement, because the rendez-
1993         --  vous will happen after elaboration.
1994
1995         if (Nkind (Original_Node (N)) = N_Accept_Statement
1996              or else Nkind (Original_Node (N)) = N_Selective_Accept)
1997           and then Restriction_Active (No_Entry_Calls_In_Elaboration_Code)
1998         then
1999            return Abandon;
2000
2001         --  If we have a function call, check it
2002
2003         elsif Nkind (N) = N_Function_Call then
2004            Check_Elab_Call (N, Outer_Scope);
2005            return OK;
2006
2007         --  If we have a procedure call, check the call, and also check
2008         --  arguments that are assignments (OUT or IN OUT mode formals).
2009
2010         elsif Nkind (N) = N_Procedure_Call_Statement then
2011            Check_Elab_Call (N, Outer_Scope, In_Init_Proc => Is_Init_Proc (E));
2012
2013            Actual := First_Actual (N);
2014            while Present (Actual) loop
2015               if Known_To_Be_Assigned (Actual) then
2016                  Check_Elab_Assign (Actual);
2017               end if;
2018
2019               Next_Actual (Actual);
2020            end loop;
2021
2022            return OK;
2023
2024         --  If we have an access attribute for a subprogram, check
2025         --  it. Suppress this behavior under debug flag.
2026
2027         elsif not Debug_Flag_Dot_UU
2028           and then Nkind (N) = N_Attribute_Reference
2029           and then Nam_In (Attribute_Name (N), Name_Access,
2030                                                Name_Unrestricted_Access)
2031           and then Is_Entity_Name (Prefix (N))
2032           and then Is_Subprogram (Entity (Prefix (N)))
2033         then
2034            Check_Elab_Call (N, Outer_Scope);
2035            return OK;
2036
2037         --  If we have a generic instantiation, check it
2038
2039         elsif Nkind (N) in N_Generic_Instantiation then
2040            Check_Elab_Instantiation (N, Outer_Scope);
2041            return OK;
2042
2043         --  Skip subprogram bodies that come from source (wait for call to
2044         --  analyze these). The reason for the come from source test is to
2045         --  avoid catching task bodies.
2046
2047         --  For task bodies, we should really avoid these too, waiting for the
2048         --  task activation, but that's too much trouble to catch for now, so
2049         --  we go in unconditionally. This is not so terrible, it means the
2050         --  error backtrace is not quite complete, and we are too eager to
2051         --  scan bodies of tasks that are unused, but this is hardly very
2052         --  significant.
2053
2054         elsif Nkind (N) = N_Subprogram_Body
2055           and then Comes_From_Source (N)
2056         then
2057            return Skip;
2058
2059         elsif Nkind (N) = N_Assignment_Statement
2060           and then Comes_From_Source (N)
2061         then
2062            Check_Elab_Assign (Name (N));
2063            return OK;
2064
2065         else
2066            return OK;
2067         end if;
2068      end Find_Elab_Reference;
2069
2070   --  Start of processing for Check_Internal_Call_Continue
2071
2072   begin
2073      --  Save outer level call if at outer level
2074
2075      if Elab_Call.Last = 0 then
2076         Outer_Level_Sloc := Loc;
2077      end if;
2078
2079      Elab_Visited.Append (E);
2080
2081      --  If the call is to a function that renames a literal, no check needed
2082
2083      if Ekind (E) = E_Enumeration_Literal then
2084         return;
2085      end if;
2086
2087      Sbody := Unit_Declaration_Node (E);
2088
2089      if Nkind (Sbody) /= N_Subprogram_Body
2090           and then
2091         Nkind (Sbody) /= N_Package_Body
2092      then
2093         Ebody := Corresponding_Body (Sbody);
2094
2095         if No (Ebody) then
2096            return;
2097         else
2098            Sbody := Unit_Declaration_Node (Ebody);
2099         end if;
2100      end if;
2101
2102      --  If the body appears after the outer level call or instantiation then
2103      --  we have an error case handled below.
2104
2105      if Earlier_In_Extended_Unit (Outer_Level_Sloc, Sloc (Sbody))
2106        and then not In_Task_Activation
2107      then
2108         null;
2109
2110      --  If we have the instantiation case we are done, since we now
2111      --  know that the body of the generic appeared earlier.
2112
2113      elsif Inst_Case then
2114         return;
2115
2116      --  Otherwise we have a call, so we trace through the called body to see
2117      --  if it has any problems.
2118
2119      else
2120         pragma Assert (Nkind (Sbody) = N_Subprogram_Body);
2121
2122         Elab_Call.Append ((Cloc => Loc, Ent => E));
2123
2124         if Debug_Flag_LL then
2125            Write_Str ("Elab_Call.Last = ");
2126            Write_Int (Int (Elab_Call.Last));
2127            Write_Str ("   Ent = ");
2128            Write_Name (Chars (E));
2129            Write_Str ("   at ");
2130            Write_Location (Sloc (N));
2131            Write_Eol;
2132         end if;
2133
2134         --  Now traverse declarations and statements of subprogram body. Note
2135         --  that we cannot simply Traverse (Sbody), since traverse does not
2136         --  normally visit subprogram bodies.
2137
2138         declare
2139            Decl : Node_Id;
2140         begin
2141            Decl := First (Declarations (Sbody));
2142            while Present (Decl) loop
2143               Traverse (Decl);
2144               Next (Decl);
2145            end loop;
2146         end;
2147
2148         Traverse (Handled_Statement_Sequence (Sbody));
2149
2150         Elab_Call.Decrement_Last;
2151         return;
2152      end if;
2153
2154      --  Here is the case of calling a subprogram where the body has not yet
2155      --  been encountered. A warning message is needed, except if this is the
2156      --  case of appearing within an aspect specification that results in
2157      --  a check call, we do not really have such a situation, so no warning
2158      --  is needed (e.g. the case of a precondition, where the call appears
2159      --  textually before the body, but in actual fact is moved to the
2160      --  appropriate subprogram body and so does not need a check).
2161
2162      declare
2163         P : Node_Id;
2164         O : Node_Id;
2165
2166      begin
2167         P := Parent (N);
2168         loop
2169            --  Keep looking at parents if we are still in the subexpression
2170
2171            if Nkind (P) in N_Subexpr then
2172               P := Parent (P);
2173
2174            --  Here P is the parent of the expression, check for special case
2175
2176            else
2177               O := Original_Node (P);
2178
2179               --  Definitely not the special case if orig node is not a pragma
2180
2181               exit when Nkind (O) /= N_Pragma;
2182
2183               --  Check we have an If statement or a null statement (happens
2184               --  when the If has been expanded to be True).
2185
2186               exit when not Nkind_In (P, N_If_Statement, N_Null_Statement);
2187
2188               --  Our special case will be indicated either by the pragma
2189               --  coming from an aspect ...
2190
2191               if Present (Corresponding_Aspect (O)) then
2192                  return;
2193
2194               --  Or, in the case of an initial condition, specifically by a
2195               --  Check pragma specifying an Initial_Condition check.
2196
2197               elsif Pragma_Name (O) = Name_Check
2198                 and then
2199                   Chars
2200                     (Expression (First (Pragma_Argument_Associations (O)))) =
2201                                                       Name_Initial_Condition
2202               then
2203                  return;
2204
2205               --  For anything else, we have an error
2206
2207               else
2208                  exit;
2209               end if;
2210            end if;
2211         end loop;
2212      end;
2213
2214      --  Not that special case, warning and dynamic check is required
2215
2216      --  If we have nothing in the call stack, then this is at the outer
2217      --  level, and the ABE is bound to occur.
2218
2219      if Elab_Call.Last = 0 then
2220         Error_Msg_Warn := SPARK_Mode /= On;
2221
2222         if Inst_Case then
2223            Error_Msg_NE
2224              ("cannot instantiate& before body seen<<", N, Orig_Ent);
2225         else
2226            Error_Msg_NE
2227              ("cannot call& before body seen<<", N, Orig_Ent);
2228         end if;
2229
2230         Error_Msg_N ("\Program_Error [<<", N);
2231         Insert_Elab_Check (N);
2232
2233      --  Call is not at outer level
2234
2235      else
2236         --  Deal with dynamic elaboration check
2237
2238         if not Elaboration_Checks_Suppressed (E) then
2239            Set_Elaboration_Entity_Required (E);
2240
2241            --  Case of no elaboration entity allocated yet
2242
2243            if No (Elaboration_Entity (E)) then
2244
2245               --  Create object declaration for elaboration entity, and put it
2246               --  just in front of the spec of the subprogram or generic unit,
2247               --  in the same scope as this unit.
2248
2249               declare
2250                  Loce : constant Source_Ptr := Sloc (E);
2251                  Ent  : constant Entity_Id  :=
2252                           Make_Defining_Identifier (Loc,
2253                             Chars => New_External_Name (Chars (E), 'E'));
2254
2255               begin
2256                  Set_Elaboration_Entity (E, Ent);
2257                  Push_Scope (Scope (E));
2258
2259                  Insert_Action (Declaration_Node (E),
2260                    Make_Object_Declaration (Loce,
2261                      Defining_Identifier => Ent,
2262                      Object_Definition   =>
2263                        New_Occurrence_Of (Standard_Short_Integer, Loce),
2264                      Expression          =>
2265                        Make_Integer_Literal (Loc, Uint_0)));
2266
2267                  --  Set elaboration flag at the point of the body
2268
2269                  Set_Elaboration_Flag (Sbody, E);
2270
2271                  --  Kill current value indication. This is necessary because
2272                  --  the tests of this flag are inserted out of sequence and
2273                  --  must not pick up bogus indications of the wrong constant
2274                  --  value. Also, this is never a true constant, since one way
2275                  --  or another, it gets reset.
2276
2277                  Set_Current_Value    (Ent, Empty);
2278                  Set_Last_Assignment  (Ent, Empty);
2279                  Set_Is_True_Constant (Ent, False);
2280                  Pop_Scope;
2281               end;
2282            end if;
2283
2284            --  Generate check of the elaboration counter
2285
2286            Insert_Elab_Check (N,
2287               Make_Attribute_Reference (Loc,
2288                 Attribute_Name => Name_Elaborated,
2289                 Prefix         => New_Occurrence_Of (E, Loc)));
2290         end if;
2291
2292         --  Generate the warning
2293
2294         if not Suppress_Elaboration_Warnings (E)
2295           and then not Elaboration_Checks_Suppressed (E)
2296
2297           --  Suppress this warning if we have a function call that occurred
2298           --  within an assertion expression, since we can get false warnings
2299           --  in this case, due to the out of order handling in this case.
2300
2301           and then
2302             (Nkind (Original_Node (N)) /= N_Function_Call
2303               or else not In_Assertion_Expression_Pragma (Original_Node (N)))
2304         then
2305            Error_Msg_Warn := SPARK_Mode /= On;
2306
2307            if Inst_Case then
2308               Error_Msg_NE
2309                 ("instantiation of& may occur before body is seen<<",
2310                  N, Orig_Ent);
2311            else
2312               Error_Msg_NE
2313                 ("call to& may occur before body is seen<<", N, Orig_Ent);
2314            end if;
2315
2316            Error_Msg_N
2317              ("\Program_Error ]<<", N);
2318
2319            Output_Calls (N);
2320         end if;
2321      end if;
2322
2323      --  Set flag to suppress further warnings on same subprogram
2324      --  unless in all errors mode
2325
2326      if not All_Errors_Mode then
2327         Set_Suppress_Elaboration_Warnings (E);
2328      end if;
2329   end Check_Internal_Call_Continue;
2330
2331   ---------------------------
2332   -- Check_Task_Activation --
2333   ---------------------------
2334
2335   procedure Check_Task_Activation (N : Node_Id) is
2336      Loc         : constant Source_Ptr := Sloc (N);
2337      Inter_Procs : constant Elist_Id   := New_Elmt_List;
2338      Intra_Procs : constant Elist_Id   := New_Elmt_List;
2339      Ent         : Entity_Id;
2340      P           : Entity_Id;
2341      Task_Scope  : Entity_Id;
2342      Cunit_SC    : Boolean := False;
2343      Decl        : Node_Id;
2344      Elmt        : Elmt_Id;
2345      Enclosing   : Entity_Id;
2346
2347      procedure Add_Task_Proc (Typ : Entity_Id);
2348      --  Add to Task_Procs the task body procedure(s) of task types in Typ.
2349      --  For record types, this procedure recurses over component types.
2350
2351      procedure Collect_Tasks (Decls : List_Id);
2352      --  Collect the types of the tasks that are to be activated in the given
2353      --  list of declarations, in order to perform elaboration checks on the
2354      --  corresponding task procedures which are called implicitly here.
2355
2356      function Outer_Unit (E : Entity_Id) return Entity_Id;
2357      --  find enclosing compilation unit of Entity, ignoring subunits, or
2358      --  else enclosing subprogram. If E is not a package, there is no need
2359      --  for inter-unit elaboration checks.
2360
2361      -------------------
2362      -- Add_Task_Proc --
2363      -------------------
2364
2365      procedure Add_Task_Proc (Typ : Entity_Id) is
2366         Comp : Entity_Id;
2367         Proc : Entity_Id := Empty;
2368
2369      begin
2370         if Is_Task_Type (Typ) then
2371            Proc := Get_Task_Body_Procedure (Typ);
2372
2373         elsif Is_Array_Type (Typ)
2374           and then Has_Task (Base_Type (Typ))
2375         then
2376            Add_Task_Proc (Component_Type (Typ));
2377
2378         elsif Is_Record_Type (Typ)
2379           and then Has_Task (Base_Type (Typ))
2380         then
2381            Comp := First_Component (Typ);
2382            while Present (Comp) loop
2383               Add_Task_Proc (Etype (Comp));
2384               Comp := Next_Component (Comp);
2385            end loop;
2386         end if;
2387
2388         --  If the task type is another unit, we will perform the usual
2389         --  elaboration check on its enclosing unit. If the type is in the
2390         --  same unit, we can trace the task body as for an internal call,
2391         --  but we only need to examine other external calls, because at
2392         --  the point the task is activated, internal subprogram bodies
2393         --  will have been elaborated already. We keep separate lists for
2394         --  each kind of task.
2395
2396         --  Skip this test if errors have occurred, since in this case
2397         --  we can get false indications.
2398
2399         if Serious_Errors_Detected /= 0 then
2400            return;
2401         end if;
2402
2403         if Present (Proc) then
2404            if Outer_Unit (Scope (Proc)) = Enclosing then
2405
2406               if No (Corresponding_Body (Unit_Declaration_Node (Proc)))
2407                 and then
2408                   (not Is_Generic_Instance (Scope (Proc))
2409                      or else
2410                    Scope (Proc) = Scope (Defining_Identifier (Decl)))
2411               then
2412                  Error_Msg_Warn := SPARK_Mode /= On;
2413                  Error_Msg_N
2414                    ("task will be activated before elaboration of its body<<",
2415                      Decl);
2416                  Error_Msg_N ("\Program_Error [<<", Decl);
2417
2418               elsif
2419                 Present (Corresponding_Body (Unit_Declaration_Node (Proc)))
2420               then
2421                  Append_Elmt (Proc, Intra_Procs);
2422               end if;
2423
2424            else
2425               --  No need for multiple entries of the same type
2426
2427               Elmt := First_Elmt (Inter_Procs);
2428               while Present (Elmt) loop
2429                  if Node (Elmt) = Proc then
2430                     return;
2431                  end if;
2432
2433                  Next_Elmt (Elmt);
2434               end loop;
2435
2436               Append_Elmt (Proc, Inter_Procs);
2437            end if;
2438         end if;
2439      end Add_Task_Proc;
2440
2441      -------------------
2442      -- Collect_Tasks --
2443      -------------------
2444
2445      procedure Collect_Tasks (Decls : List_Id) is
2446      begin
2447         if Present (Decls) then
2448            Decl := First (Decls);
2449            while Present (Decl) loop
2450               if Nkind (Decl) = N_Object_Declaration
2451                 and then Has_Task (Etype (Defining_Identifier (Decl)))
2452               then
2453                  Add_Task_Proc (Etype (Defining_Identifier (Decl)));
2454               end if;
2455
2456               Next (Decl);
2457            end loop;
2458         end if;
2459      end Collect_Tasks;
2460
2461      ----------------
2462      -- Outer_Unit --
2463      ----------------
2464
2465      function Outer_Unit (E : Entity_Id) return Entity_Id is
2466         Outer : Entity_Id;
2467
2468      begin
2469         Outer := E;
2470         while Present (Outer) loop
2471            if Elaboration_Checks_Suppressed (Outer) then
2472               Cunit_SC := True;
2473            end if;
2474
2475            exit when Is_Child_Unit (Outer)
2476              or else Scope (Outer) = Standard_Standard
2477              or else Ekind (Outer) /= E_Package;
2478            Outer := Scope (Outer);
2479         end loop;
2480
2481         return Outer;
2482      end Outer_Unit;
2483
2484   --  Start of processing for Check_Task_Activation
2485
2486   begin
2487      Enclosing := Outer_Unit (Current_Scope);
2488
2489      --  Find all tasks declared in the current unit
2490
2491      if Nkind (N) = N_Package_Body then
2492         P := Unit_Declaration_Node (Corresponding_Spec (N));
2493
2494         Collect_Tasks (Declarations (N));
2495         Collect_Tasks (Visible_Declarations (Specification (P)));
2496         Collect_Tasks (Private_Declarations (Specification (P)));
2497
2498      elsif Nkind (N) = N_Package_Declaration then
2499         Collect_Tasks (Visible_Declarations (Specification (N)));
2500         Collect_Tasks (Private_Declarations (Specification (N)));
2501
2502      else
2503         Collect_Tasks (Declarations (N));
2504      end if;
2505
2506      --  We only perform detailed checks in all tasks are library level
2507      --  entities. If the master is a subprogram or task, activation will
2508      --  depend on the activation of the master itself.
2509
2510      --  Should dynamic checks be added in the more general case???
2511
2512      if Ekind (Enclosing) /= E_Package then
2513         return;
2514      end if;
2515
2516      --  For task types defined in other units, we want the unit containing
2517      --  the task body to be elaborated before the current one.
2518
2519      Elmt := First_Elmt (Inter_Procs);
2520      while Present (Elmt) loop
2521         Ent := Node (Elmt);
2522         Task_Scope := Outer_Unit (Scope (Ent));
2523
2524         if not Is_Compilation_Unit (Task_Scope) then
2525            null;
2526
2527         elsif Suppress_Elaboration_Warnings (Task_Scope)
2528           or else Elaboration_Checks_Suppressed (Task_Scope)
2529         then
2530            null;
2531
2532         elsif Dynamic_Elaboration_Checks then
2533            if not Elaboration_Checks_Suppressed (Ent)
2534              and then not Cunit_SC
2535              and then
2536                not Restriction_Active (No_Entry_Calls_In_Elaboration_Code)
2537            then
2538               --  Runtime elaboration check required. Generate check of the
2539               --  elaboration counter for the unit containing the entity.
2540
2541               Insert_Elab_Check (N,
2542                 Make_Attribute_Reference (Loc,
2543                   Attribute_Name => Name_Elaborated,
2544                   Prefix =>
2545                     New_Occurrence_Of (Spec_Entity (Task_Scope), Loc)));
2546            end if;
2547
2548         else
2549            --  Force the binder to elaborate other unit first
2550
2551            if not Suppress_Elaboration_Warnings (Ent)
2552              and then not Elaboration_Checks_Suppressed (Ent)
2553              and then Elab_Info_Messages
2554              and then not Suppress_Elaboration_Warnings (Task_Scope)
2555              and then not Elaboration_Checks_Suppressed (Task_Scope)
2556            then
2557               Error_Msg_Node_2 := Task_Scope;
2558               Error_Msg_NE
2559                 ("info: activation of an instance of task type&" &
2560                  " requires pragma Elaborate_All on &?", N, Ent);
2561            end if;
2562
2563            Activate_Elaborate_All_Desirable (N, Task_Scope);
2564            Set_Suppress_Elaboration_Warnings (Task_Scope);
2565         end if;
2566
2567         Next_Elmt (Elmt);
2568      end loop;
2569
2570      --  For tasks declared in the current unit, trace other calls within
2571      --  the task procedure bodies, which are available.
2572
2573      In_Task_Activation := True;
2574
2575      Elmt := First_Elmt (Intra_Procs);
2576      while Present (Elmt) loop
2577         Ent := Node (Elmt);
2578         Check_Internal_Call_Continue (N, Ent, Enclosing, Ent);
2579         Next_Elmt (Elmt);
2580      end loop;
2581
2582      In_Task_Activation := False;
2583   end Check_Task_Activation;
2584
2585   --------------------------------
2586   -- Set_Elaboration_Constraint --
2587   --------------------------------
2588
2589   procedure Set_Elaboration_Constraint
2590    (Call : Node_Id;
2591     Subp : Entity_Id;
2592     Scop : Entity_Id)
2593   is
2594      Elab_Unit  : Entity_Id;
2595
2596      --  Check whether this is a call to an Initialize subprogram for a
2597      --  controlled type. Note that Call can also be a 'Access attribute
2598      --  reference, which now generates an elaboration check.
2599
2600      Init_Call  : constant Boolean :=
2601                     Nkind (Call) = N_Procedure_Call_Statement
2602                       and then Chars (Subp) = Name_Initialize
2603                       and then Comes_From_Source (Subp)
2604                       and then Present (Parameter_Associations (Call))
2605                       and then Is_Controlled (Etype (First_Actual (Call)));
2606   begin
2607      --  If the unit is mentioned in a with_clause of the current unit, it is
2608      --  visible, and we can set the elaboration flag.
2609
2610      if Is_Immediately_Visible (Scop)
2611        or else (Is_Child_Unit (Scop) and then Is_Visible_Lib_Unit (Scop))
2612      then
2613         Activate_Elaborate_All_Desirable (Call, Scop);
2614         Set_Suppress_Elaboration_Warnings (Scop, True);
2615         return;
2616      end if;
2617
2618      --  If this is not an initialization call or a call using object notation
2619      --  we know that the unit of the called entity is in the context, and
2620      --  we can set the flag as well. The unit need not be visible if the call
2621      --  occurs within an instantiation.
2622
2623      if Is_Init_Proc (Subp)
2624        or else Init_Call
2625        or else Nkind (Original_Node (Call)) = N_Selected_Component
2626      then
2627         null;  --  detailed processing follows.
2628
2629      else
2630         Activate_Elaborate_All_Desirable (Call, Scop);
2631         Set_Suppress_Elaboration_Warnings (Scop, True);
2632         return;
2633      end if;
2634
2635      --  If the unit is not in the context, there must be an intermediate unit
2636      --  that is, on which we need to place to elaboration flag. This happens
2637      --  with init proc calls.
2638
2639      if Is_Init_Proc (Subp)
2640        or else Init_Call
2641      then
2642         --  The initialization call is on an object whose type is not declared
2643         --  in the same scope as the subprogram. The type of the object must
2644         --  be a subtype of the type of operation. This object is the first
2645         --  actual in the call.
2646
2647         declare
2648            Typ : constant Entity_Id :=
2649                    Etype (First (Parameter_Associations (Call)));
2650         begin
2651            Elab_Unit := Scope (Typ);
2652            while (Present (Elab_Unit))
2653              and then not Is_Compilation_Unit (Elab_Unit)
2654            loop
2655               Elab_Unit := Scope (Elab_Unit);
2656            end loop;
2657         end;
2658
2659      --  If original node uses selected component notation, the prefix is
2660      --  visible and determines the scope that must be elaborated. After
2661      --  rewriting, the prefix is the first actual in the call.
2662
2663      elsif Nkind (Original_Node (Call)) = N_Selected_Component then
2664         Elab_Unit := Scope (Etype (First (Parameter_Associations (Call))));
2665
2666      --  Not one of special cases above
2667
2668      else
2669         --  Using previously computed scope. If the elaboration check is
2670         --  done after analysis, the scope is not visible any longer, but
2671         --  must still be in the context.
2672
2673         Elab_Unit := Scop;
2674      end if;
2675
2676      Activate_Elaborate_All_Desirable (Call, Elab_Unit);
2677      Set_Suppress_Elaboration_Warnings (Elab_Unit, True);
2678   end Set_Elaboration_Constraint;
2679
2680   ------------------------
2681   -- Get_Referenced_Ent --
2682   ------------------------
2683
2684   function Get_Referenced_Ent (N : Node_Id) return Entity_Id is
2685      Nam : Node_Id;
2686
2687   begin
2688      if Nkind (N) = N_Attribute_Reference then
2689         Nam := Prefix (N);
2690      else
2691         Nam := Name (N);
2692      end if;
2693
2694      if No (Nam) then
2695         return Empty;
2696      elsif Nkind (Nam) = N_Selected_Component then
2697         return Entity (Selector_Name (Nam));
2698      elsif not Is_Entity_Name (Nam) then
2699         return Empty;
2700      else
2701         return Entity (Nam);
2702      end if;
2703   end Get_Referenced_Ent;
2704
2705   ----------------------
2706   -- Has_Generic_Body --
2707   ----------------------
2708
2709   function Has_Generic_Body (N : Node_Id) return Boolean is
2710      Ent  : constant Entity_Id := Get_Generic_Entity (N);
2711      Decl : constant Node_Id   := Unit_Declaration_Node (Ent);
2712      Scop : Entity_Id;
2713
2714      function Find_Body_In (E : Entity_Id; N : Node_Id) return Node_Id;
2715      --  Determine if the list of nodes headed by N and linked by Next
2716      --  contains a package body for the package spec entity E, and if so
2717      --  return the package body. If not, then returns Empty.
2718
2719      function Load_Package_Body (Nam : Unit_Name_Type) return Node_Id;
2720      --  This procedure is called load the unit whose name is given by Nam.
2721      --  This unit is being loaded to see whether it contains an optional
2722      --  generic body. The returned value is the loaded unit, which is always
2723      --  a package body (only package bodies can contain other entities in the
2724      --  sense in which Has_Generic_Body is interested). We only attempt to
2725      --  load bodies if we are generating code. If we are in semantics check
2726      --  only mode, then it would be wrong to load bodies that are not
2727      --  required from a semantic point of view, so in this case we return
2728      --  Empty. The result is that the caller may incorrectly decide that a
2729      --  generic spec does not have a body when in fact it does, but the only
2730      --  harm in this is that some warnings on elaboration problems may be
2731      --  lost in semantic checks only mode, which is not big loss. We also
2732      --  return Empty if we go for a body and it is not there.
2733
2734      function Locate_Corresponding_Body (PE : Entity_Id) return Node_Id;
2735      --  PE is the entity for a package spec. This function locates the
2736      --  corresponding package body, returning Empty if none is found. The
2737      --  package body returned is fully parsed but may not yet be analyzed,
2738      --  so only syntactic fields should be referenced.
2739
2740      ------------------
2741      -- Find_Body_In --
2742      ------------------
2743
2744      function Find_Body_In (E : Entity_Id; N : Node_Id) return Node_Id is
2745         Nod : Node_Id;
2746
2747      begin
2748         Nod := N;
2749         while Present (Nod) loop
2750
2751            --  If we found the package body we are looking for, return it
2752
2753            if Nkind (Nod) = N_Package_Body
2754              and then Chars (Defining_Unit_Name (Nod)) = Chars (E)
2755            then
2756               return Nod;
2757
2758            --  If we found the stub for the body, go after the subunit,
2759            --  loading it if necessary.
2760
2761            elsif Nkind (Nod) = N_Package_Body_Stub
2762              and then Chars (Defining_Identifier (Nod)) = Chars (E)
2763            then
2764               if Present (Library_Unit (Nod)) then
2765                  return Unit (Library_Unit (Nod));
2766
2767               else
2768                  return Load_Package_Body (Get_Unit_Name (Nod));
2769               end if;
2770
2771            --  If neither package body nor stub, keep looking on chain
2772
2773            else
2774               Next (Nod);
2775            end if;
2776         end loop;
2777
2778         return Empty;
2779      end Find_Body_In;
2780
2781      -----------------------
2782      -- Load_Package_Body --
2783      -----------------------
2784
2785      function Load_Package_Body (Nam : Unit_Name_Type) return Node_Id is
2786         U : Unit_Number_Type;
2787
2788      begin
2789         if Operating_Mode /= Generate_Code then
2790            return Empty;
2791         else
2792            U :=
2793              Load_Unit
2794                (Load_Name  => Nam,
2795                 Required   => False,
2796                 Subunit    => False,
2797                 Error_Node => N);
2798
2799            if U = No_Unit then
2800               return Empty;
2801            else
2802               return Unit (Cunit (U));
2803            end if;
2804         end if;
2805      end Load_Package_Body;
2806
2807      -------------------------------
2808      -- Locate_Corresponding_Body --
2809      -------------------------------
2810
2811      function Locate_Corresponding_Body (PE : Entity_Id) return Node_Id is
2812         Spec  : constant Node_Id   := Declaration_Node (PE);
2813         Decl  : constant Node_Id   := Parent (Spec);
2814         Scop  : constant Entity_Id := Scope (PE);
2815         PBody : Node_Id;
2816
2817      begin
2818         if Is_Library_Level_Entity (PE) then
2819
2820            --  If package is a library unit that requires a body, we have no
2821            --  choice but to go after that body because it might contain an
2822            --  optional body for the original generic package.
2823
2824            if Unit_Requires_Body (PE) then
2825
2826               --  Load the body. Note that we are a little careful here to use
2827               --  Spec to get the unit number, rather than PE or Decl, since
2828               --  in the case where the package is itself a library level
2829               --  instantiation, Spec will properly reference the generic
2830               --  template, which is what we really want.
2831
2832               return
2833                 Load_Package_Body
2834                   (Get_Body_Name (Unit_Name (Get_Source_Unit (Spec))));
2835
2836            --  But if the package is a library unit that does NOT require
2837            --  a body, then no body is permitted, so we are sure that there
2838            --  is no body for the original generic package.
2839
2840            else
2841               return Empty;
2842            end if;
2843
2844         --  Otherwise look and see if we are embedded in a further package
2845
2846         elsif Is_Package_Or_Generic_Package (Scop) then
2847
2848            --  If so, get the body of the enclosing package, and look in
2849            --  its package body for the package body we are looking for.
2850
2851            PBody := Locate_Corresponding_Body (Scop);
2852
2853            if No (PBody) then
2854               return Empty;
2855            else
2856               return Find_Body_In (PE, First (Declarations (PBody)));
2857            end if;
2858
2859         --  If we are not embedded in a further package, then the body
2860         --  must be in the same declarative part as we are.
2861
2862         else
2863            return Find_Body_In (PE, Next (Decl));
2864         end if;
2865      end Locate_Corresponding_Body;
2866
2867   --  Start of processing for Has_Generic_Body
2868
2869   begin
2870      if Present (Corresponding_Body (Decl)) then
2871         return True;
2872
2873      elsif Unit_Requires_Body (Ent) then
2874         return True;
2875
2876      --  Compilation units cannot have optional bodies
2877
2878      elsif Is_Compilation_Unit (Ent) then
2879         return False;
2880
2881      --  Otherwise look at what scope we are in
2882
2883      else
2884         Scop := Scope (Ent);
2885
2886         --  Case of entity is in other than a package spec, in this case
2887         --  the body, if present, must be in the same declarative part.
2888
2889         if not Is_Package_Or_Generic_Package (Scop) then
2890            declare
2891               P : Node_Id;
2892
2893            begin
2894               --  Declaration node may get us a spec, so if so, go to
2895               --  the parent declaration.
2896
2897               P := Declaration_Node (Ent);
2898               while not Is_List_Member (P) loop
2899                  P := Parent (P);
2900               end loop;
2901
2902               return Present (Find_Body_In (Ent, Next (P)));
2903            end;
2904
2905         --  If the entity is in a package spec, then we have to locate
2906         --  the corresponding package body, and look there.
2907
2908         else
2909            declare
2910               PBody : constant Node_Id := Locate_Corresponding_Body (Scop);
2911
2912            begin
2913               if No (PBody) then
2914                  return False;
2915               else
2916                  return
2917                    Present
2918                      (Find_Body_In (Ent, (First (Declarations (PBody)))));
2919               end if;
2920            end;
2921         end if;
2922      end if;
2923   end Has_Generic_Body;
2924
2925   -----------------------
2926   -- Insert_Elab_Check --
2927   -----------------------
2928
2929   procedure Insert_Elab_Check (N : Node_Id; C : Node_Id := Empty) is
2930      Nod : Node_Id;
2931      Loc : constant Source_Ptr := Sloc (N);
2932
2933      Chk : Node_Id;
2934      --  The check (N_Raise_Program_Error) node to be inserted
2935
2936   begin
2937      --  If expansion is disabled, do not generate any checks. Also
2938      --  skip checks if any subunits are missing because in either
2939      --  case we lack the full information that we need, and no object
2940      --  file will be created in any case.
2941
2942      if not Expander_Active or else Subunits_Missing then
2943         return;
2944      end if;
2945
2946      --  If we have a generic instantiation, where Instance_Spec is set,
2947      --  then this field points to a generic instance spec that has
2948      --  been inserted before the instantiation node itself, so that
2949      --  is where we want to insert a check.
2950
2951      if Nkind (N) in N_Generic_Instantiation
2952        and then Present (Instance_Spec (N))
2953      then
2954         Nod := Instance_Spec (N);
2955      else
2956         Nod := N;
2957      end if;
2958
2959      --  Build check node, possibly with condition
2960
2961      Chk :=
2962        Make_Raise_Program_Error (Loc, Reason => PE_Access_Before_Elaboration);
2963
2964      if Present (C) then
2965         Set_Condition (Chk, Make_Op_Not (Loc, Right_Opnd => C));
2966      end if;
2967
2968      --  If we are inserting at the top level, insert in Aux_Decls
2969
2970      if Nkind (Parent (Nod)) = N_Compilation_Unit then
2971         declare
2972            ADN : constant Node_Id := Aux_Decls_Node (Parent (Nod));
2973
2974         begin
2975            if No (Declarations (ADN)) then
2976               Set_Declarations (ADN, New_List (Chk));
2977            else
2978               Append_To (Declarations (ADN), Chk);
2979            end if;
2980
2981            Analyze (Chk);
2982         end;
2983
2984      --  Otherwise just insert as an action on the node in question
2985
2986      else
2987         Insert_Action (Nod, Chk);
2988      end if;
2989   end Insert_Elab_Check;
2990
2991   -------------------------------
2992   -- Is_Finalization_Procedure --
2993   -------------------------------
2994
2995   function Is_Finalization_Procedure (Id : Entity_Id) return Boolean is
2996   begin
2997      --  Check whether Id is a procedure with at least one parameter
2998
2999      if Ekind (Id) = E_Procedure
3000        and then Present (First_Formal (Id))
3001      then
3002         declare
3003            Typ      : constant Entity_Id := Etype (First_Formal (Id));
3004            Deep_Fin : Entity_Id := Empty;
3005            Fin      : Entity_Id := Empty;
3006
3007         begin
3008            --  If the type of the first formal does not require finalization
3009            --  actions, then this is definitely not [Deep_]Finalize.
3010
3011            if not Needs_Finalization (Typ) then
3012               return False;
3013            end if;
3014
3015            --  At this point we have the following scenario:
3016
3017            --    procedure Name (Param1 : [in] [out] Ctrl[; Param2 : ...]);
3018
3019            --  Recover the two possible versions of [Deep_]Finalize using the
3020            --  type of the first parameter and compare with the input.
3021
3022            Deep_Fin := TSS (Typ, TSS_Deep_Finalize);
3023
3024            if Is_Controlled (Typ) then
3025               Fin := Find_Prim_Op (Typ, Name_Finalize);
3026            end if;
3027
3028            return
3029                (Present (Deep_Fin) and then Id = Deep_Fin)
3030              or else
3031                (Present (Fin) and then Id = Fin);
3032         end;
3033      end if;
3034
3035      return False;
3036   end Is_Finalization_Procedure;
3037
3038   ------------------
3039   -- Output_Calls --
3040   ------------------
3041
3042   procedure Output_Calls (N : Node_Id) is
3043      Ent : Entity_Id;
3044
3045      function Is_Printable_Error_Name (Nm : Name_Id) return Boolean;
3046      --  An internal function, used to determine if a name, Nm, is either
3047      --  a non-internal name, or is an internal name that is printable
3048      --  by the error message circuits (i.e. it has a single upper
3049      --  case letter at the end).
3050
3051      function Is_Printable_Error_Name (Nm : Name_Id) return Boolean is
3052      begin
3053         if not Is_Internal_Name (Nm) then
3054            return True;
3055
3056         elsif Name_Len = 1 then
3057            return False;
3058
3059         else
3060            Name_Len := Name_Len - 1;
3061            return not Is_Internal_Name;
3062         end if;
3063      end Is_Printable_Error_Name;
3064
3065   --  Start of processing for Output_Calls
3066
3067   begin
3068      for J in reverse 1 .. Elab_Call.Last loop
3069         Error_Msg_Sloc := Elab_Call.Table (J).Cloc;
3070
3071         Ent := Elab_Call.Table (J).Ent;
3072
3073         if Is_Generic_Unit (Ent) then
3074            Error_Msg_NE ("\??& instantiated #", N, Ent);
3075
3076         elsif Is_Init_Proc (Ent) then
3077            Error_Msg_N ("\??initialization procedure called #", N);
3078
3079         elsif Is_Printable_Error_Name (Chars (Ent)) then
3080            Error_Msg_NE ("\??& called #", N, Ent);
3081
3082         else
3083            Error_Msg_N ("\?? called #", N);
3084         end if;
3085      end loop;
3086   end Output_Calls;
3087
3088   ----------------------------
3089   -- Same_Elaboration_Scope --
3090   ----------------------------
3091
3092   function Same_Elaboration_Scope (Scop1, Scop2 : Entity_Id) return Boolean is
3093      S1 : Entity_Id;
3094      S2 : Entity_Id;
3095
3096   begin
3097      --  Find elaboration scope for Scop1
3098      --  This is either a subprogram or a compilation unit.
3099
3100      S1 := Scop1;
3101      while S1 /= Standard_Standard
3102        and then not Is_Compilation_Unit (S1)
3103        and then (Ekind (S1) = E_Package
3104                    or else
3105                  Ekind (S1) = E_Protected_Type
3106                    or else
3107                  Ekind (S1) = E_Block)
3108      loop
3109         S1 := Scope (S1);
3110      end loop;
3111
3112      --  Find elaboration scope for Scop2
3113
3114      S2 := Scop2;
3115      while S2 /= Standard_Standard
3116        and then not Is_Compilation_Unit (S2)
3117        and then (Ekind (S2) = E_Package
3118                    or else
3119                  Ekind (S2) = E_Protected_Type
3120                    or else
3121                  Ekind (S2) = E_Block)
3122      loop
3123         S2 := Scope (S2);
3124      end loop;
3125
3126      return S1 = S2;
3127   end Same_Elaboration_Scope;
3128
3129   -----------------
3130   -- Set_C_Scope --
3131   -----------------
3132
3133   procedure Set_C_Scope is
3134   begin
3135      while not Is_Compilation_Unit (C_Scope) loop
3136         C_Scope := Scope (C_Scope);
3137      end loop;
3138   end Set_C_Scope;
3139
3140   -----------------
3141   -- Spec_Entity --
3142   -----------------
3143
3144   function Spec_Entity (E : Entity_Id) return Entity_Id is
3145      Decl : Node_Id;
3146
3147   begin
3148      --  Check for case of body entity
3149      --  Why is the check for E_Void needed???
3150
3151      if Ekind_In (E, E_Void, E_Subprogram_Body, E_Package_Body) then
3152         Decl := E;
3153
3154         loop
3155            Decl := Parent (Decl);
3156            exit when Nkind (Decl) in N_Proper_Body;
3157         end loop;
3158
3159         return Corresponding_Spec (Decl);
3160
3161      else
3162         return E;
3163      end if;
3164   end Spec_Entity;
3165
3166   -------------------
3167   -- Supply_Bodies --
3168   -------------------
3169
3170   procedure Supply_Bodies (N : Node_Id) is
3171   begin
3172      if Nkind (N) = N_Subprogram_Declaration then
3173         declare
3174            Ent : constant Entity_Id := Defining_Unit_Name (Specification (N));
3175         begin
3176
3177            --  Internal subprograms will already have a generated body, so
3178            --  there is no need to provide a stub for them.
3179
3180            if No (Corresponding_Body (N)) then
3181               declare
3182                  Loc     : constant Source_Ptr := Sloc (N);
3183                  B       : Node_Id;
3184                  Formals : constant List_Id := Copy_Parameter_List (Ent);
3185                  Nam     : constant Entity_Id :=
3186                              Make_Defining_Identifier (Loc, Chars (Ent));
3187                  Spec    : Node_Id;
3188                  Stats   : constant List_Id :=
3189                              New_List
3190                               (Make_Raise_Program_Error (Loc,
3191                                  Reason => PE_Access_Before_Elaboration));
3192
3193               begin
3194                  if Ekind (Ent) = E_Function then
3195                     Spec :=
3196                        Make_Function_Specification (Loc,
3197                          Defining_Unit_Name => Nam,
3198                          Parameter_Specifications => Formals,
3199                          Result_Definition =>
3200                            New_Copy_Tree
3201                              (Result_Definition (Specification (N))));
3202
3203                     --  We cannot reliably make a return statement for this
3204                     --  body, but none is needed because the call raises
3205                     --  program error.
3206
3207                     Set_Return_Present (Ent);
3208
3209                  else
3210                     Spec :=
3211                        Make_Procedure_Specification (Loc,
3212                          Defining_Unit_Name => Nam,
3213                          Parameter_Specifications => Formals);
3214                  end if;
3215
3216                  B := Make_Subprogram_Body (Loc,
3217                          Specification => Spec,
3218                          Declarations => New_List,
3219                          Handled_Statement_Sequence =>
3220                            Make_Handled_Sequence_Of_Statements (Loc,  Stats));
3221                  Insert_After (N, B);
3222                  Analyze (B);
3223               end;
3224            end if;
3225         end;
3226
3227      elsif Nkind (N) = N_Package_Declaration then
3228         declare
3229            Spec : constant Node_Id := Specification (N);
3230         begin
3231            Push_Scope (Defining_Unit_Name (Spec));
3232            Supply_Bodies (Visible_Declarations (Spec));
3233            Supply_Bodies (Private_Declarations (Spec));
3234            Pop_Scope;
3235         end;
3236      end if;
3237   end Supply_Bodies;
3238
3239   procedure Supply_Bodies (L : List_Id) is
3240      Elmt : Node_Id;
3241   begin
3242      if Present (L) then
3243         Elmt := First (L);
3244         while Present (Elmt) loop
3245            Supply_Bodies (Elmt);
3246            Next (Elmt);
3247         end loop;
3248      end if;
3249   end Supply_Bodies;
3250
3251   ------------
3252   -- Within --
3253   ------------
3254
3255   function Within (E1, E2 : Entity_Id) return Boolean is
3256      Scop : Entity_Id;
3257   begin
3258      Scop := E1;
3259      loop
3260         if Scop = E2 then
3261            return True;
3262         elsif Scop = Standard_Standard then
3263            return False;
3264         else
3265            Scop := Scope (Scop);
3266         end if;
3267      end loop;
3268   end Within;
3269
3270   --------------------------
3271   -- Within_Elaborate_All --
3272   --------------------------
3273
3274   function Within_Elaborate_All
3275     (Unit : Unit_Number_Type;
3276      E    : Entity_Id) return Boolean
3277   is
3278      type Unit_Number_Set is array (Main_Unit .. Last_Unit) of Boolean;
3279      pragma Pack (Unit_Number_Set);
3280
3281      Seen : Unit_Number_Set := (others => False);
3282      --  Seen (X) is True after we have seen unit X in the walk. This is used
3283      --  to prevent processing the same unit more than once.
3284
3285      Result : Boolean := False;
3286
3287      procedure Helper (Unit : Unit_Number_Type);
3288      --  This helper procedure does all the work for Within_Elaborate_All. It
3289      --  walks the dependency graph, and sets Result to True if it finds an
3290      --  appropriate Elaborate_All.
3291
3292      ------------
3293      -- Helper --
3294      ------------
3295
3296      procedure Helper (Unit : Unit_Number_Type) is
3297         CU : constant Node_Id := Cunit (Unit);
3298
3299         Item    : Node_Id;
3300         Item2   : Node_Id;
3301         Elab_Id : Entity_Id;
3302         Par     : Node_Id;
3303
3304      begin
3305         if Seen (Unit) then
3306            return;
3307         else
3308            Seen (Unit) := True;
3309         end if;
3310
3311         --  First, check for Elaborate_Alls on this unit
3312
3313         Item := First (Context_Items (CU));
3314         while Present (Item) loop
3315            if Nkind (Item) = N_Pragma
3316              and then Pragma_Name (Item) = Name_Elaborate_All
3317            then
3318               --  Return if some previous error on the pragma itself. The
3319               --  pragma may be unanalyzed, because of a previous error, or
3320               --  if it is the context of a subunit, inherited by its parent.
3321
3322               if Error_Posted (Item) or else not Analyzed (Item) then
3323                  return;
3324               end if;
3325
3326               Elab_Id :=
3327                 Entity
3328                   (Expression (First (Pragma_Argument_Associations (Item))));
3329
3330               if E = Elab_Id then
3331                  Result := True;
3332                  return;
3333               end if;
3334
3335               Par := Parent (Unit_Declaration_Node (Elab_Id));
3336
3337               Item2 := First (Context_Items (Par));
3338               while Present (Item2) loop
3339                  if Nkind (Item2) = N_With_Clause
3340                    and then Entity (Name (Item2)) = E
3341                    and then not Limited_Present (Item2)
3342                  then
3343                     Result := True;
3344                     return;
3345                  end if;
3346
3347                  Next (Item2);
3348               end loop;
3349            end if;
3350
3351            Next (Item);
3352         end loop;
3353
3354         --  Second, recurse on with's. We could do this as part of the above
3355         --  loop, but it's probably more efficient to have two loops, because
3356         --  the relevant Elaborate_All is likely to be on the initial unit. In
3357         --  other words, we're walking the with's breadth-first. This part is
3358         --  only necessary in the dynamic elaboration model.
3359
3360         if Dynamic_Elaboration_Checks then
3361            Item := First (Context_Items (CU));
3362            while Present (Item) loop
3363               if Nkind (Item) = N_With_Clause
3364                 and then not Limited_Present (Item)
3365               then
3366                  --  Note: the following call to Get_Cunit_Unit_Number does a
3367                  --  linear search, which could be slow, but it's OK because
3368                  --  we're about to give a warning anyway. Also, there might
3369                  --  be hundreds of units, but not millions. If it turns out
3370                  --  to be a problem, we could store the Get_Cunit_Unit_Number
3371                  --  in each N_Compilation_Unit node, but that would involve
3372                  --  rearranging N_Compilation_Unit_Aux to make room.
3373
3374                  Helper (Get_Cunit_Unit_Number (Library_Unit (Item)));
3375
3376                  if Result then
3377                     return;
3378                  end if;
3379               end if;
3380
3381               Next (Item);
3382            end loop;
3383         end if;
3384      end Helper;
3385
3386   --  Start of processing for Within_Elaborate_All
3387
3388   begin
3389      Helper (Unit);
3390      return Result;
3391   end Within_Elaborate_All;
3392
3393end Sem_Elab;
3394