1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2016, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree
; use Atree
;
27 with Debug
; use Debug
;
28 with Debug_A
; use Debug_A
;
29 with Exp_Aggr
; use Exp_Aggr
;
30 with Exp_SPARK
; use Exp_SPARK
;
31 with Exp_Attr
; use Exp_Attr
;
32 with Exp_Ch2
; use Exp_Ch2
;
33 with Exp_Ch3
; use Exp_Ch3
;
34 with Exp_Ch4
; use Exp_Ch4
;
35 with Exp_Ch5
; use Exp_Ch5
;
36 with Exp_Ch6
; use Exp_Ch6
;
37 with Exp_Ch7
; use Exp_Ch7
;
38 with Exp_Ch8
; use Exp_Ch8
;
39 with Exp_Ch9
; use Exp_Ch9
;
40 with Exp_Ch11
; use Exp_Ch11
;
41 with Exp_Ch12
; use Exp_Ch12
;
42 with Exp_Ch13
; use Exp_Ch13
;
43 with Exp_Prag
; use Exp_Prag
;
45 with Rtsfind
; use Rtsfind
;
47 with Sem_Ch8
; use Sem_Ch8
;
48 with Sem_Util
; use Sem_Util
;
49 with Sinfo
; use Sinfo
;
52 package body Expander
is
58 -- The following table is used to save values of the Expander_Active flag
59 -- when they are saved by Expander_Mode_Save_And_Set. We use an extendible
60 -- table (which is a bit of overkill) because it is easier than figuring
61 -- out a maximum value or bothering with range checks.
63 package Expander_Flags
is new Table
.Table
(
64 Table_Component_Type
=> Boolean,
65 Table_Index_Type
=> Int
,
68 Table_Increment
=> 200,
69 Table_Name
=> "Expander_Flags");
71 Abort_Bug_Box_Error
: exception;
72 -- Arbitrary exception to raise for implementation of -gnatd.B. See "when
73 -- N_Abort_Statement" below. See also debug.adb.
79 procedure Expand
(N
: Node_Id
) is
81 -- If we were analyzing a default expression (or other spec expression)
82 -- the Full_Analysis flag must be off. If we are in expansion mode then
83 -- we must be performing a full analysis. If we are analyzing a generic
84 -- then Expansion must be off.
87 (not (Full_Analysis
and then In_Spec_Expression
)
88 and then (Full_Analysis
or else not Expander_Active
)
89 and then not (Inside_A_Generic
and then Expander_Active
));
91 -- The GNATprove_Mode flag indicates that a light expansion for formal
92 -- verification should be used. This expansion is never done inside
93 -- generics, because otherwise, this breaks the name resolution
94 -- mechanism for generic instances.
96 if GNATprove_Mode
then
97 if not Inside_A_Generic
then
101 Set_Analyzed
(N
, Full_Analysis
);
103 -- Regular expansion is normally followed by special handling for
104 -- transient scopes for unconstrained results, etc. but this is not
105 -- needed, and in general cannot be done correctly, in this mode, so
110 -- There are three reasons for the Expander_Active flag to be false
112 -- The first is when are not generating code. In this mode the
113 -- Full_Analysis flag indicates whether we are performing a complete
114 -- analysis, in which case Full_Analysis = True or a pre-analysis in
115 -- which case Full_Analysis = False. See the spec of Sem for more info
118 -- The second reason for the Expander_Active flag to be False is that
119 -- we are performing a pre-analysis. During pre-analysis all expansion
120 -- activity is turned off to make sure nodes are semantically decorated
121 -- but no extra nodes are generated. This is for instance needed for
122 -- the first pass of aggregate semantic processing. Note that in this
123 -- case the Full_Analysis flag is set to False because the node will
124 -- subsequently be re-analyzed with expansion on (see the spec of sem).
126 -- Finally, expansion is turned off in a regular compilation if there
127 -- are serious errors. In that case there will be no further expansion,
128 -- but one cleanup action may be required: if a transient scope was
129 -- created (e.g. for a function that returns an unconstrained type) the
130 -- scope may still be on the stack, and must be removed explicitly,
131 -- given that the expansion actions that would normally process it will
132 -- not take place. This prevents cascaded errors due to stack mismatch.
134 elsif not Expander_Active
then
135 Set_Analyzed
(N
, Full_Analysis
);
137 if Serious_Errors_Detected
> 0 and then Scope_Is_Transient
then
139 (Scope_Stack
.Last
).Actions_To_Be_Wrapped
:= (others => No_List
);
147 Debug_A_Entry
("expanding ", N
);
149 -- Processing depends on node kind. For full details on the
150 -- expansion activity required in each case, see bodies of
151 -- corresponding expand routines.
154 when N_Abort_Statement
=>
155 Expand_N_Abort_Statement
(N
);
157 -- If -gnatd.B switch was given, crash the compiler. See
158 -- debug.adb for explanation.
160 if Debug_Flag_Dot_BB
then
161 raise Abort_Bug_Box_Error
;
164 when N_Accept_Statement
=>
165 Expand_N_Accept_Statement
(N
);
168 Expand_N_Aggregate
(N
);
171 Expand_N_Allocator
(N
);
174 Expand_N_And_Then
(N
);
176 when N_Assignment_Statement
=>
177 Expand_N_Assignment_Statement
(N
);
179 when N_Asynchronous_Select
=>
180 Expand_N_Asynchronous_Select
(N
);
182 when N_Attribute_Definition_Clause
=>
183 Expand_N_Attribute_Definition_Clause
(N
);
185 when N_Attribute_Reference
=>
186 Expand_N_Attribute_Reference
(N
);
188 when N_Block_Statement
=>
189 Expand_N_Block_Statement
(N
);
191 when N_Case_Expression
=>
192 Expand_N_Case_Expression
(N
);
194 when N_Case_Statement
=>
195 Expand_N_Case_Statement
(N
);
197 when N_Conditional_Entry_Call
=>
198 Expand_N_Conditional_Entry_Call
(N
);
200 when N_Delay_Relative_Statement
=>
201 Expand_N_Delay_Relative_Statement
(N
);
203 when N_Delay_Until_Statement
=>
204 Expand_N_Delay_Until_Statement
(N
);
207 Expand_N_Entry_Body
(N
);
209 when N_Entry_Call_Statement
=>
210 Expand_N_Entry_Call_Statement
(N
);
212 when N_Entry_Declaration
=>
213 Expand_N_Entry_Declaration
(N
);
215 when N_Exception_Declaration
=>
216 Expand_N_Exception_Declaration
(N
);
218 when N_Exception_Renaming_Declaration
=>
219 Expand_N_Exception_Renaming_Declaration
(N
);
221 when N_Exit_Statement
=>
222 Expand_N_Exit_Statement
(N
);
224 when N_Expanded_Name
=>
225 Expand_N_Expanded_Name
(N
);
227 when N_Explicit_Dereference
=>
228 Expand_N_Explicit_Dereference
(N
);
230 when N_Expression_With_Actions
=>
231 Expand_N_Expression_With_Actions
(N
);
233 when N_Extended_Return_Statement
=>
234 Expand_N_Extended_Return_Statement
(N
);
236 when N_Extension_Aggregate
=>
237 Expand_N_Extension_Aggregate
(N
);
239 when N_Free_Statement
=>
240 Expand_N_Free_Statement
(N
);
242 when N_Freeze_Entity
=>
243 Expand_N_Freeze_Entity
(N
);
245 when N_Full_Type_Declaration
=>
246 Expand_N_Full_Type_Declaration
(N
);
248 when N_Function_Call
=>
249 Expand_N_Function_Call
(N
);
251 when N_Generic_Instantiation
=>
252 Expand_N_Generic_Instantiation
(N
);
254 when N_Goto_Statement
=>
255 Expand_N_Goto_Statement
(N
);
257 when N_Handled_Sequence_Of_Statements
=>
258 Expand_N_Handled_Sequence_Of_Statements
(N
);
261 Expand_N_Identifier
(N
);
263 when N_If_Expression
=>
264 Expand_N_If_Expression
(N
);
266 when N_Indexed_Component
=>
267 Expand_N_Indexed_Component
(N
);
269 when N_If_Statement
=>
270 Expand_N_If_Statement
(N
);
275 when N_Loop_Statement
=>
276 Expand_N_Loop_Statement
(N
);
284 when N_Object_Declaration
=>
285 Expand_N_Object_Declaration
(N
);
287 when N_Object_Renaming_Declaration
=>
288 Expand_N_Object_Renaming_Declaration
(N
);
300 Expand_N_Op_Concat
(N
);
303 Expand_N_Op_Divide
(N
);
309 Expand_N_Op_Expon
(N
);
324 Expand_N_Op_Minus
(N
);
329 when N_Op_Multiply
=>
330 Expand_N_Op_Multiply
(N
);
342 Expand_N_Op_Plus
(N
);
347 when N_Op_Rotate_Left
=>
348 Expand_N_Op_Rotate_Left
(N
);
350 when N_Op_Rotate_Right
=>
351 Expand_N_Op_Rotate_Right
(N
);
353 when N_Op_Shift_Left
=>
354 Expand_N_Op_Shift_Left
(N
);
356 when N_Op_Shift_Right
=>
357 Expand_N_Op_Shift_Right
(N
);
359 when N_Op_Shift_Right_Arithmetic
=>
360 Expand_N_Op_Shift_Right_Arithmetic
(N
);
362 when N_Op_Subtract
=>
363 Expand_N_Op_Subtract
(N
);
369 Expand_N_Or_Else
(N
);
371 when N_Package_Body
=>
372 Expand_N_Package_Body
(N
);
374 when N_Package_Declaration
=>
375 Expand_N_Package_Declaration
(N
);
377 when N_Package_Renaming_Declaration
=>
378 Expand_N_Package_Renaming_Declaration
(N
);
380 when N_Subprogram_Renaming_Declaration
=>
381 Expand_N_Subprogram_Renaming_Declaration
(N
);
386 when N_Procedure_Call_Statement
=>
387 Expand_N_Procedure_Call_Statement
(N
);
389 when N_Protected_Type_Declaration
=>
390 Expand_N_Protected_Type_Declaration
(N
);
392 when N_Protected_Body
=>
393 Expand_N_Protected_Body
(N
);
395 when N_Qualified_Expression
=>
396 Expand_N_Qualified_Expression
(N
);
398 when N_Quantified_Expression
=>
399 Expand_N_Quantified_Expression
(N
);
401 when N_Raise_Statement
=>
402 Expand_N_Raise_Statement
(N
);
404 when N_Raise_Constraint_Error
=>
405 Expand_N_Raise_Constraint_Error
(N
);
407 when N_Raise_Expression
=>
408 Expand_N_Raise_Expression
(N
);
410 when N_Raise_Program_Error
=>
411 Expand_N_Raise_Program_Error
(N
);
413 when N_Raise_Storage_Error
=>
414 Expand_N_Raise_Storage_Error
(N
);
416 when N_Real_Literal
=>
417 Expand_N_Real_Literal
(N
);
419 when N_Record_Representation_Clause
=>
420 Expand_N_Record_Representation_Clause
(N
);
422 when N_Requeue_Statement
=>
423 Expand_N_Requeue_Statement
(N
);
425 when N_Simple_Return_Statement
=>
426 Expand_N_Simple_Return_Statement
(N
);
428 when N_Selected_Component
=>
429 Expand_N_Selected_Component
(N
);
431 when N_Selective_Accept
=>
432 Expand_N_Selective_Accept
(N
);
434 when N_Single_Protected_Declaration
=>
435 Expand_N_Single_Protected_Declaration
(N
);
437 when N_Single_Task_Declaration
=>
438 Expand_N_Single_Task_Declaration
(N
);
443 when N_Subtype_Indication
=>
444 Expand_N_Subtype_Indication
(N
);
446 when N_Subprogram_Body
=>
447 Expand_N_Subprogram_Body
(N
);
449 when N_Subprogram_Body_Stub
=>
450 Expand_N_Subprogram_Body_Stub
(N
);
452 when N_Subprogram_Declaration
=>
453 Expand_N_Subprogram_Declaration
(N
);
456 Expand_N_Task_Body
(N
);
458 when N_Task_Type_Declaration
=>
459 Expand_N_Task_Type_Declaration
(N
);
461 when N_Timed_Entry_Call
=>
462 Expand_N_Timed_Entry_Call
(N
);
464 when N_Type_Conversion
=>
465 Expand_N_Type_Conversion
(N
);
467 when N_Unchecked_Expression
=>
468 Expand_N_Unchecked_Expression
(N
);
470 when N_Unchecked_Type_Conversion
=>
471 Expand_N_Unchecked_Type_Conversion
(N
);
473 when N_Variant_Part
=>
474 Expand_N_Variant_Part
(N
);
476 -- For all other node kinds, no expansion activity required
484 when RE_Not_Available
=>
488 -- Set result as analyzed and then do a possible transient wrap. The
489 -- transient wrap must be done after the Analyzed flag is set on, so
490 -- that we do not get a recursive attempt to expand the node N.
494 -- Deal with transient scopes
496 if Scope_Is_Transient
and then N
= Node_To_Be_Wrapped
then
498 when N_Statement_Other_Than_Procedure_Call |
499 N_Procedure_Call_Statement
=>
500 Wrap_Transient_Statement
(N
);
502 when N_Object_Declaration |
503 N_Object_Renaming_Declaration |
504 N_Subtype_Declaration
=>
505 Wrap_Transient_Declaration
(N
);
507 when others => Wrap_Transient_Expression
(N
);
511 Debug_A_Exit
("expanding ", N
, " (done)");
515 ---------------------------
516 -- Expander_Mode_Restore --
517 ---------------------------
519 procedure Expander_Mode_Restore
is
521 -- Not active (has no effect) in ASIS and GNATprove modes (see comments
522 -- in spec of Expander_Mode_Save_And_Set).
524 if ASIS_Mode
or GNATprove_Mode
then
528 -- Otherwise restore the flag
530 Expander_Active
:= Expander_Flags
.Table
(Expander_Flags
.Last
);
531 Expander_Flags
.Decrement_Last
;
533 -- Keep expander off if serious errors detected. In this case we do not
534 -- need expansion, and continued expansion may cause cascaded errors or
537 if Serious_Errors_Detected
/= 0 then
538 Expander_Active
:= False;
540 end Expander_Mode_Restore
;
542 --------------------------------
543 -- Expander_Mode_Save_And_Set --
544 --------------------------------
546 procedure Expander_Mode_Save_And_Set
(Status
: Boolean) is
548 -- Not active (has no effect) in ASIS and GNATprove modes (see comments
549 -- in spec of Expander_Mode_Save_And_Set).
551 if ASIS_Mode
or GNATprove_Mode
then
555 -- Otherwise save and set the flag
557 Expander_Flags
.Increment_Last
;
558 Expander_Flags
.Table
(Expander_Flags
.Last
) := Expander_Active
;
559 Expander_Active
:= Status
;
560 end Expander_Mode_Save_And_Set
;