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fbf5a39b | 1 | ------------------------------------------------------------------------------ |
996ae0b0 RK |
2 | -- -- |
3 | -- GNAT COMPILER COMPONENTS -- | |
4 | -- -- | |
5 | -- S E M _ E V A L -- | |
6 | -- -- | |
7 | -- B o d y -- | |
8 | -- -- | |
0356699b | 9 | -- Copyright (C) 1992-2005, Free Software Foundation, Inc. -- |
996ae0b0 RK |
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 2, 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 COPYING. If not, write -- | |
cb5fee25 KC |
19 | -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- |
20 | -- Boston, MA 02110-1301, USA. -- | |
996ae0b0 RK |
21 | -- -- |
22 | -- GNAT was originally developed by the GNAT team at New York University. -- | |
71ff80dc | 23 | -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
996ae0b0 RK |
24 | -- -- |
25 | ------------------------------------------------------------------------------ | |
26 | ||
27 | with Atree; use Atree; | |
28 | with Checks; use Checks; | |
29 | with Debug; use Debug; | |
30 | with Einfo; use Einfo; | |
31 | with Elists; use Elists; | |
32 | with Errout; use Errout; | |
33 | with Eval_Fat; use Eval_Fat; | |
8cbb664e | 34 | with Exp_Util; use Exp_Util; |
0356699b | 35 | with Lib; use Lib; |
996ae0b0 RK |
36 | with Nmake; use Nmake; |
37 | with Nlists; use Nlists; | |
38 | with Opt; use Opt; | |
39 | with Sem; use Sem; | |
40 | with Sem_Cat; use Sem_Cat; | |
b5bd964f | 41 | with Sem_Ch6; use Sem_Ch6; |
996ae0b0 RK |
42 | with Sem_Ch8; use Sem_Ch8; |
43 | with Sem_Res; use Sem_Res; | |
44 | with Sem_Util; use Sem_Util; | |
45 | with Sem_Type; use Sem_Type; | |
46 | with Sem_Warn; use Sem_Warn; | |
47 | with Sinfo; use Sinfo; | |
48 | with Snames; use Snames; | |
49 | with Stand; use Stand; | |
50 | with Stringt; use Stringt; | |
07fc65c4 | 51 | with Tbuild; use Tbuild; |
996ae0b0 RK |
52 | |
53 | package body Sem_Eval is | |
54 | ||
55 | ----------------------------------------- | |
56 | -- Handling of Compile Time Evaluation -- | |
57 | ----------------------------------------- | |
58 | ||
59 | -- The compile time evaluation of expressions is distributed over several | |
60 | -- Eval_xxx procedures. These procedures are called immediatedly after | |
61 | -- a subexpression is resolved and is therefore accomplished in a bottom | |
62 | -- up fashion. The flags are synthesized using the following approach. | |
63 | ||
64 | -- Is_Static_Expression is determined by following the detailed rules | |
65 | -- in RM 4.9(4-14). This involves testing the Is_Static_Expression | |
66 | -- flag of the operands in many cases. | |
67 | ||
68 | -- Raises_Constraint_Error is set if any of the operands have the flag | |
69 | -- set or if an attempt to compute the value of the current expression | |
70 | -- results in detection of a runtime constraint error. | |
71 | ||
72 | -- As described in the spec, the requirement is that Is_Static_Expression | |
73 | -- be accurately set, and in addition for nodes for which this flag is set, | |
74 | -- Raises_Constraint_Error must also be set. Furthermore a node which has | |
75 | -- Is_Static_Expression set, and Raises_Constraint_Error clear, then the | |
76 | -- requirement is that the expression value must be precomputed, and the | |
77 | -- node is either a literal, or the name of a constant entity whose value | |
78 | -- is a static expression. | |
79 | ||
80 | -- The general approach is as follows. First compute Is_Static_Expression. | |
81 | -- If the node is not static, then the flag is left off in the node and | |
82 | -- we are all done. Otherwise for a static node, we test if any of the | |
83 | -- operands will raise constraint error, and if so, propagate the flag | |
84 | -- Raises_Constraint_Error to the result node and we are done (since the | |
85 | -- error was already posted at a lower level). | |
86 | ||
87 | -- For the case of a static node whose operands do not raise constraint | |
88 | -- error, we attempt to evaluate the node. If this evaluation succeeds, | |
89 | -- then the node is replaced by the result of this computation. If the | |
90 | -- evaluation raises constraint error, then we rewrite the node with | |
91 | -- Apply_Compile_Time_Constraint_Error to raise the exception and also | |
92 | -- to post appropriate error messages. | |
93 | ||
94 | ---------------- | |
95 | -- Local Data -- | |
96 | ---------------- | |
97 | ||
98 | type Bits is array (Nat range <>) of Boolean; | |
99 | -- Used to convert unsigned (modular) values for folding logical ops | |
100 | ||
07fc65c4 GB |
101 | -- The following definitions are used to maintain a cache of nodes that |
102 | -- have compile time known values. The cache is maintained only for | |
103 | -- discrete types (the most common case), and is populated by calls to | |
104 | -- Compile_Time_Known_Value and Expr_Value, but only used by Expr_Value | |
105 | -- since it is possible for the status to change (in particular it is | |
106 | -- possible for a node to get replaced by a constraint error node). | |
107 | ||
108 | CV_Bits : constant := 5; | |
109 | -- Number of low order bits of Node_Id value used to reference entries | |
110 | -- in the cache table. | |
111 | ||
112 | CV_Cache_Size : constant Nat := 2 ** CV_Bits; | |
113 | -- Size of cache for compile time values | |
114 | ||
115 | subtype CV_Range is Nat range 0 .. CV_Cache_Size; | |
116 | ||
117 | type CV_Entry is record | |
118 | N : Node_Id; | |
119 | V : Uint; | |
120 | end record; | |
121 | ||
122 | type CV_Cache_Array is array (CV_Range) of CV_Entry; | |
123 | ||
124 | CV_Cache : CV_Cache_Array := (others => (Node_High_Bound, Uint_0)); | |
125 | -- This is the actual cache, with entries consisting of node/value pairs, | |
126 | -- and the impossible value Node_High_Bound used for unset entries. | |
127 | ||
996ae0b0 RK |
128 | ----------------------- |
129 | -- Local Subprograms -- | |
130 | ----------------------- | |
131 | ||
996ae0b0 RK |
132 | function From_Bits (B : Bits; T : Entity_Id) return Uint; |
133 | -- Converts a bit string of length B'Length to a Uint value to be used | |
134 | -- for a target of type T, which is a modular type. This procedure | |
135 | -- includes the necessary reduction by the modulus in the case of a | |
136 | -- non-binary modulus (for a binary modulus, the bit string is the | |
137 | -- right length any way so all is well). | |
138 | ||
139 | function Get_String_Val (N : Node_Id) return Node_Id; | |
140 | -- Given a tree node for a folded string or character value, returns | |
141 | -- the corresponding string literal or character literal (one of the | |
142 | -- two must be available, or the operand would not have been marked | |
143 | -- as foldable in the earlier analysis of the operation). | |
144 | ||
07fc65c4 GB |
145 | function OK_Bits (N : Node_Id; Bits : Uint) return Boolean; |
146 | -- Bits represents the number of bits in an integer value to be computed | |
147 | -- (but the value has not been computed yet). If this value in Bits is | |
148 | -- reasonable, a result of True is returned, with the implication that | |
149 | -- the caller should go ahead and complete the calculation. If the value | |
150 | -- in Bits is unreasonably large, then an error is posted on node N, and | |
151 | -- False is returned (and the caller skips the proposed calculation). | |
152 | ||
996ae0b0 RK |
153 | procedure Out_Of_Range (N : Node_Id); |
154 | -- This procedure is called if it is determined that node N, which | |
155 | -- appears in a non-static context, is a compile time known value | |
156 | -- which is outside its range, i.e. the range of Etype. This is used | |
157 | -- in contexts where this is an illegality if N is static, and should | |
158 | -- generate a warning otherwise. | |
159 | ||
160 | procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id); | |
161 | -- N and Exp are nodes representing an expression, Exp is known | |
162 | -- to raise CE. N is rewritten in term of Exp in the optimal way. | |
163 | ||
164 | function String_Type_Len (Stype : Entity_Id) return Uint; | |
165 | -- Given a string type, determines the length of the index type, or, | |
166 | -- if this index type is non-static, the length of the base type of | |
167 | -- this index type. Note that if the string type is itself static, | |
168 | -- then the index type is static, so the second case applies only | |
169 | -- if the string type passed is non-static. | |
170 | ||
171 | function Test (Cond : Boolean) return Uint; | |
172 | pragma Inline (Test); | |
173 | -- This function simply returns the appropriate Boolean'Pos value | |
174 | -- corresponding to the value of Cond as a universal integer. It is | |
175 | -- used for producing the result of the static evaluation of the | |
176 | -- logical operators | |
177 | ||
178 | procedure Test_Expression_Is_Foldable | |
179 | (N : Node_Id; | |
180 | Op1 : Node_Id; | |
181 | Stat : out Boolean; | |
182 | Fold : out Boolean); | |
183 | -- Tests to see if expression N whose single operand is Op1 is foldable, | |
184 | -- i.e. the operand value is known at compile time. If the operation is | |
185 | -- foldable, then Fold is True on return, and Stat indicates whether | |
186 | -- the result is static (i.e. both operands were static). Note that it | |
187 | -- is quite possible for Fold to be True, and Stat to be False, since | |
188 | -- there are cases in which we know the value of an operand even though | |
189 | -- it is not technically static (e.g. the static lower bound of a range | |
190 | -- whose upper bound is non-static). | |
191 | -- | |
192 | -- If Stat is set False on return, then Expression_Is_Foldable makes a | |
193 | -- call to Check_Non_Static_Context on the operand. If Fold is False on | |
194 | -- return, then all processing is complete, and the caller should | |
195 | -- return, since there is nothing else to do. | |
196 | ||
197 | procedure Test_Expression_Is_Foldable | |
198 | (N : Node_Id; | |
199 | Op1 : Node_Id; | |
200 | Op2 : Node_Id; | |
201 | Stat : out Boolean; | |
202 | Fold : out Boolean); | |
203 | -- Same processing, except applies to an expression N with two operands | |
204 | -- Op1 and Op2. | |
205 | ||
206 | procedure To_Bits (U : Uint; B : out Bits); | |
207 | -- Converts a Uint value to a bit string of length B'Length | |
208 | ||
209 | ------------------------------ | |
210 | -- Check_Non_Static_Context -- | |
211 | ------------------------------ | |
212 | ||
213 | procedure Check_Non_Static_Context (N : Node_Id) is | |
fbf5a39b AC |
214 | T : constant Entity_Id := Etype (N); |
215 | Checks_On : constant Boolean := | |
996ae0b0 RK |
216 | not Index_Checks_Suppressed (T) |
217 | and not Range_Checks_Suppressed (T); | |
218 | ||
219 | begin | |
fbf5a39b | 220 | -- Ignore cases of non-scalar types or error types |
996ae0b0 | 221 | |
fbf5a39b | 222 | if T = Any_Type or else not Is_Scalar_Type (T) then |
996ae0b0 | 223 | return; |
fbf5a39b | 224 | end if; |
996ae0b0 | 225 | |
fbf5a39b AC |
226 | -- At this stage we have a scalar type. If we have an expression |
227 | -- that raises CE, then we already issued a warning or error msg | |
228 | -- so there is nothing more to be done in this routine. | |
229 | ||
230 | if Raises_Constraint_Error (N) then | |
231 | return; | |
232 | end if; | |
233 | ||
234 | -- Now we have a scalar type which is not marked as raising a | |
235 | -- constraint error exception. The main purpose of this routine | |
236 | -- is to deal with static expressions appearing in a non-static | |
237 | -- context. That means that if we do not have a static expression | |
238 | -- then there is not much to do. The one case that we deal with | |
239 | -- here is that if we have a floating-point value that is out of | |
240 | -- range, then we post a warning that an infinity will result. | |
241 | ||
242 | if not Is_Static_Expression (N) then | |
243 | if Is_Floating_Point_Type (T) | |
244 | and then Is_Out_Of_Range (N, Base_Type (T)) | |
245 | then | |
246 | Error_Msg_N | |
247 | ("?float value out of range, infinity will be generated", N); | |
248 | end if; | |
996ae0b0 | 249 | |
996ae0b0 RK |
250 | return; |
251 | end if; | |
252 | ||
253 | -- Here we have the case of outer level static expression of | |
254 | -- scalar type, where the processing of this procedure is needed. | |
255 | ||
256 | -- For real types, this is where we convert the value to a machine | |
257 | -- number (see RM 4.9(38)). Also see ACVC test C490001. We should | |
258 | -- only need to do this if the parent is a constant declaration, | |
259 | -- since in other cases, gigi should do the necessary conversion | |
260 | -- correctly, but experimentation shows that this is not the case | |
261 | -- on all machines, in particular if we do not convert all literals | |
262 | -- to machine values in non-static contexts, then ACVC test C490001 | |
263 | -- fails on Sparc/Solaris and SGI/Irix. | |
264 | ||
265 | if Nkind (N) = N_Real_Literal | |
266 | and then not Is_Machine_Number (N) | |
267 | and then not Is_Generic_Type (Etype (N)) | |
268 | and then Etype (N) /= Universal_Real | |
996ae0b0 RK |
269 | then |
270 | -- Check that value is in bounds before converting to machine | |
271 | -- number, so as not to lose case where value overflows in the | |
272 | -- least significant bit or less. See B490001. | |
273 | ||
274 | if Is_Out_Of_Range (N, Base_Type (T)) then | |
275 | Out_Of_Range (N); | |
276 | return; | |
277 | end if; | |
278 | ||
279 | -- Note: we have to copy the node, to avoid problems with conformance | |
280 | -- of very similar numbers (see ACVC tests B4A010C and B63103A). | |
281 | ||
282 | Rewrite (N, New_Copy (N)); | |
283 | ||
284 | if not Is_Floating_Point_Type (T) then | |
285 | Set_Realval | |
286 | (N, Corresponding_Integer_Value (N) * Small_Value (T)); | |
287 | ||
288 | elsif not UR_Is_Zero (Realval (N)) then | |
996ae0b0 | 289 | |
fbf5a39b AC |
290 | -- Note: even though RM 4.9(38) specifies biased rounding, |
291 | -- this has been modified by AI-100 in order to prevent | |
292 | -- confusing differences in rounding between static and | |
293 | -- non-static expressions. AI-100 specifies that the effect | |
294 | -- of such rounding is implementation dependent, and in GNAT | |
295 | -- we round to nearest even to match the run-time behavior. | |
996ae0b0 | 296 | |
fbf5a39b AC |
297 | Set_Realval |
298 | (N, Machine (Base_Type (T), Realval (N), Round_Even, N)); | |
996ae0b0 RK |
299 | end if; |
300 | ||
301 | Set_Is_Machine_Number (N); | |
302 | end if; | |
303 | ||
304 | -- Check for out of range universal integer. This is a non-static | |
305 | -- context, so the integer value must be in range of the runtime | |
306 | -- representation of universal integers. | |
307 | ||
308 | -- We do this only within an expression, because that is the only | |
309 | -- case in which non-static universal integer values can occur, and | |
310 | -- furthermore, Check_Non_Static_Context is currently (incorrectly???) | |
311 | -- called in contexts like the expression of a number declaration where | |
312 | -- we certainly want to allow out of range values. | |
313 | ||
314 | if Etype (N) = Universal_Integer | |
315 | and then Nkind (N) = N_Integer_Literal | |
316 | and then Nkind (Parent (N)) in N_Subexpr | |
317 | and then | |
318 | (Intval (N) < Expr_Value (Type_Low_Bound (Universal_Integer)) | |
319 | or else | |
320 | Intval (N) > Expr_Value (Type_High_Bound (Universal_Integer))) | |
321 | then | |
322 | Apply_Compile_Time_Constraint_Error | |
07fc65c4 GB |
323 | (N, "non-static universal integer value out of range?", |
324 | CE_Range_Check_Failed); | |
996ae0b0 RK |
325 | |
326 | -- Check out of range of base type | |
327 | ||
328 | elsif Is_Out_Of_Range (N, Base_Type (T)) then | |
329 | Out_Of_Range (N); | |
330 | ||
331 | -- Give warning if outside subtype (where one or both of the | |
332 | -- bounds of the subtype is static). This warning is omitted | |
333 | -- if the expression appears in a range that could be null | |
334 | -- (warnings are handled elsewhere for this case). | |
335 | ||
336 | elsif T /= Base_Type (T) | |
337 | and then Nkind (Parent (N)) /= N_Range | |
338 | then | |
339 | if Is_In_Range (N, T) then | |
340 | null; | |
341 | ||
342 | elsif Is_Out_Of_Range (N, T) then | |
343 | Apply_Compile_Time_Constraint_Error | |
07fc65c4 | 344 | (N, "value not in range of}?", CE_Range_Check_Failed); |
996ae0b0 RK |
345 | |
346 | elsif Checks_On then | |
347 | Enable_Range_Check (N); | |
348 | ||
349 | else | |
350 | Set_Do_Range_Check (N, False); | |
351 | end if; | |
352 | end if; | |
353 | end Check_Non_Static_Context; | |
354 | ||
355 | --------------------------------- | |
356 | -- Check_String_Literal_Length -- | |
357 | --------------------------------- | |
358 | ||
359 | procedure Check_String_Literal_Length (N : Node_Id; Ttype : Entity_Id) is | |
360 | begin | |
361 | if not Raises_Constraint_Error (N) | |
362 | and then Is_Constrained (Ttype) | |
363 | then | |
364 | if | |
365 | UI_From_Int (String_Length (Strval (N))) /= String_Type_Len (Ttype) | |
366 | then | |
367 | Apply_Compile_Time_Constraint_Error | |
368 | (N, "string length wrong for}?", | |
07fc65c4 | 369 | CE_Length_Check_Failed, |
996ae0b0 RK |
370 | Ent => Ttype, |
371 | Typ => Ttype); | |
372 | end if; | |
373 | end if; | |
374 | end Check_String_Literal_Length; | |
375 | ||
376 | -------------------------- | |
377 | -- Compile_Time_Compare -- | |
378 | -------------------------- | |
379 | ||
fbf5a39b AC |
380 | function Compile_Time_Compare |
381 | (L, R : Node_Id; | |
f44fe430 | 382 | Rec : Boolean := False) return Compare_Result |
fbf5a39b | 383 | is |
996ae0b0 RK |
384 | Ltyp : constant Entity_Id := Etype (L); |
385 | Rtyp : constant Entity_Id := Etype (R); | |
386 | ||
387 | procedure Compare_Decompose | |
388 | (N : Node_Id; | |
389 | R : out Node_Id; | |
390 | V : out Uint); | |
391 | -- This procedure decomposes the node N into an expression node | |
392 | -- and a signed offset, so that the value of N is equal to the | |
393 | -- value of R plus the value V (which may be negative). If no | |
394 | -- such decomposition is possible, then on return R is a copy | |
395 | -- of N, and V is set to zero. | |
396 | ||
397 | function Compare_Fixup (N : Node_Id) return Node_Id; | |
398 | -- This function deals with replacing 'Last and 'First references | |
399 | -- with their corresponding type bounds, which we then can compare. | |
400 | -- The argument is the original node, the result is the identity, | |
401 | -- unless we have a 'Last/'First reference in which case the value | |
402 | -- returned is the appropriate type bound. | |
403 | ||
404 | function Is_Same_Value (L, R : Node_Id) return Boolean; | |
405 | -- Returns True iff L and R represent expressions that definitely | |
406 | -- have identical (but not necessarily compile time known) values | |
407 | -- Indeed the caller is expected to have already dealt with the | |
408 | -- cases of compile time known values, so these are not tested here. | |
409 | ||
410 | ----------------------- | |
411 | -- Compare_Decompose -- | |
412 | ----------------------- | |
413 | ||
414 | procedure Compare_Decompose | |
415 | (N : Node_Id; | |
416 | R : out Node_Id; | |
417 | V : out Uint) | |
418 | is | |
419 | begin | |
420 | if Nkind (N) = N_Op_Add | |
421 | and then Nkind (Right_Opnd (N)) = N_Integer_Literal | |
422 | then | |
423 | R := Left_Opnd (N); | |
424 | V := Intval (Right_Opnd (N)); | |
425 | return; | |
426 | ||
427 | elsif Nkind (N) = N_Op_Subtract | |
428 | and then Nkind (Right_Opnd (N)) = N_Integer_Literal | |
429 | then | |
430 | R := Left_Opnd (N); | |
431 | V := UI_Negate (Intval (Right_Opnd (N))); | |
432 | return; | |
433 | ||
434 | elsif Nkind (N) = N_Attribute_Reference then | |
435 | ||
436 | if Attribute_Name (N) = Name_Succ then | |
437 | R := First (Expressions (N)); | |
438 | V := Uint_1; | |
439 | return; | |
440 | ||
441 | elsif Attribute_Name (N) = Name_Pred then | |
442 | R := First (Expressions (N)); | |
443 | V := Uint_Minus_1; | |
444 | return; | |
445 | end if; | |
446 | end if; | |
447 | ||
448 | R := N; | |
449 | V := Uint_0; | |
450 | end Compare_Decompose; | |
451 | ||
452 | ------------------- | |
453 | -- Compare_Fixup -- | |
454 | ------------------- | |
455 | ||
456 | function Compare_Fixup (N : Node_Id) return Node_Id is | |
457 | Indx : Node_Id; | |
458 | Xtyp : Entity_Id; | |
459 | Subs : Nat; | |
460 | ||
461 | begin | |
462 | if Nkind (N) = N_Attribute_Reference | |
463 | and then (Attribute_Name (N) = Name_First | |
464 | or else | |
465 | Attribute_Name (N) = Name_Last) | |
466 | then | |
467 | Xtyp := Etype (Prefix (N)); | |
468 | ||
469 | -- If we have no type, then just abandon the attempt to do | |
470 | -- a fixup, this is probably the result of some other error. | |
471 | ||
472 | if No (Xtyp) then | |
473 | return N; | |
474 | end if; | |
475 | ||
476 | -- Dereference an access type | |
477 | ||
478 | if Is_Access_Type (Xtyp) then | |
479 | Xtyp := Designated_Type (Xtyp); | |
480 | end if; | |
481 | ||
482 | -- If we don't have an array type at this stage, something | |
483 | -- is peculiar, e.g. another error, and we abandon the attempt | |
484 | -- at a fixup. | |
485 | ||
486 | if not Is_Array_Type (Xtyp) then | |
487 | return N; | |
488 | end if; | |
489 | ||
490 | -- Ignore unconstrained array, since bounds are not meaningful | |
491 | ||
492 | if not Is_Constrained (Xtyp) then | |
493 | return N; | |
494 | end if; | |
495 | ||
c3de5c4c ES |
496 | if Ekind (Xtyp) = E_String_Literal_Subtype then |
497 | if Attribute_Name (N) = Name_First then | |
498 | return String_Literal_Low_Bound (Xtyp); | |
499 | ||
500 | else -- Attribute_Name (N) = Name_Last | |
501 | return Make_Integer_Literal (Sloc (N), | |
502 | Intval => Intval (String_Literal_Low_Bound (Xtyp)) | |
503 | + String_Literal_Length (Xtyp)); | |
504 | end if; | |
505 | end if; | |
506 | ||
996ae0b0 RK |
507 | -- Find correct index type |
508 | ||
509 | Indx := First_Index (Xtyp); | |
510 | ||
511 | if Present (Expressions (N)) then | |
512 | Subs := UI_To_Int (Expr_Value (First (Expressions (N)))); | |
513 | ||
514 | for J in 2 .. Subs loop | |
515 | Indx := Next_Index (Indx); | |
516 | end loop; | |
517 | end if; | |
518 | ||
519 | Xtyp := Etype (Indx); | |
520 | ||
521 | if Attribute_Name (N) = Name_First then | |
522 | return Type_Low_Bound (Xtyp); | |
523 | ||
524 | else -- Attribute_Name (N) = Name_Last | |
525 | return Type_High_Bound (Xtyp); | |
526 | end if; | |
527 | end if; | |
528 | ||
529 | return N; | |
530 | end Compare_Fixup; | |
531 | ||
532 | ------------------- | |
533 | -- Is_Same_Value -- | |
534 | ------------------- | |
535 | ||
536 | function Is_Same_Value (L, R : Node_Id) return Boolean is | |
537 | Lf : constant Node_Id := Compare_Fixup (L); | |
538 | Rf : constant Node_Id := Compare_Fixup (R); | |
539 | ||
fbf5a39b AC |
540 | function Is_Same_Subscript (L, R : List_Id) return Boolean; |
541 | -- L, R are the Expressions values from two attribute nodes | |
542 | -- for First or Last attributes. Either may be set to No_List | |
543 | -- if no expressions are present (indicating subscript 1). | |
544 | -- The result is True if both expressions represent the same | |
545 | -- subscript (note that one case is where one subscript is | |
546 | -- missing and the other is explicitly set to 1). | |
547 | ||
548 | ----------------------- | |
549 | -- Is_Same_Subscript -- | |
550 | ----------------------- | |
551 | ||
552 | function Is_Same_Subscript (L, R : List_Id) return Boolean is | |
553 | begin | |
554 | if L = No_List then | |
555 | if R = No_List then | |
556 | return True; | |
557 | else | |
558 | return Expr_Value (First (R)) = Uint_1; | |
559 | end if; | |
560 | ||
561 | else | |
562 | if R = No_List then | |
563 | return Expr_Value (First (L)) = Uint_1; | |
564 | else | |
565 | return Expr_Value (First (L)) = Expr_Value (First (R)); | |
566 | end if; | |
567 | end if; | |
568 | end Is_Same_Subscript; | |
569 | ||
570 | -- Start of processing for Is_Same_Value | |
571 | ||
996ae0b0 RK |
572 | begin |
573 | -- Values are the same if they are the same identifier and the | |
fbf5a39b AC |
574 | -- identifier refers to a constant object (E_Constant). This |
575 | -- does not however apply to Float types, since we may have two | |
576 | -- NaN values and they should never compare equal. | |
996ae0b0 RK |
577 | |
578 | if Nkind (Lf) = N_Identifier and then Nkind (Rf) = N_Identifier | |
579 | and then Entity (Lf) = Entity (Rf) | |
fbf5a39b | 580 | and then not Is_Floating_Point_Type (Etype (L)) |
996ae0b0 RK |
581 | and then (Ekind (Entity (Lf)) = E_Constant or else |
582 | Ekind (Entity (Lf)) = E_In_Parameter or else | |
583 | Ekind (Entity (Lf)) = E_Loop_Parameter) | |
584 | then | |
585 | return True; | |
586 | ||
587 | -- Or if they are compile time known and identical | |
588 | ||
589 | elsif Compile_Time_Known_Value (Lf) | |
590 | and then | |
591 | Compile_Time_Known_Value (Rf) | |
592 | and then Expr_Value (Lf) = Expr_Value (Rf) | |
593 | then | |
594 | return True; | |
595 | ||
596 | -- Or if they are both 'First or 'Last values applying to the | |
597 | -- same entity (first and last don't change even if value does) | |
598 | ||
599 | elsif Nkind (Lf) = N_Attribute_Reference | |
600 | and then | |
601 | Nkind (Rf) = N_Attribute_Reference | |
602 | and then Attribute_Name (Lf) = Attribute_Name (Rf) | |
603 | and then (Attribute_Name (Lf) = Name_First | |
604 | or else | |
605 | Attribute_Name (Lf) = Name_Last) | |
606 | and then Is_Entity_Name (Prefix (Lf)) | |
607 | and then Is_Entity_Name (Prefix (Rf)) | |
608 | and then Entity (Prefix (Lf)) = Entity (Prefix (Rf)) | |
fbf5a39b | 609 | and then Is_Same_Subscript (Expressions (Lf), Expressions (Rf)) |
996ae0b0 RK |
610 | then |
611 | return True; | |
612 | ||
613 | -- All other cases, we can't tell | |
614 | ||
615 | else | |
616 | return False; | |
617 | end if; | |
618 | end Is_Same_Value; | |
619 | ||
620 | -- Start of processing for Compile_Time_Compare | |
621 | ||
622 | begin | |
07fc65c4 GB |
623 | -- If either operand could raise constraint error, then we cannot |
624 | -- know the result at compile time (since CE may be raised!) | |
625 | ||
626 | if not (Cannot_Raise_Constraint_Error (L) | |
627 | and then | |
628 | Cannot_Raise_Constraint_Error (R)) | |
629 | then | |
630 | return Unknown; | |
631 | end if; | |
632 | ||
633 | -- Identical operands are most certainly equal | |
634 | ||
996ae0b0 RK |
635 | if L = R then |
636 | return EQ; | |
637 | ||
638 | -- If expressions have no types, then do not attempt to determine | |
639 | -- if they are the same, since something funny is going on. One | |
640 | -- case in which this happens is during generic template analysis, | |
641 | -- when bounds are not fully analyzed. | |
642 | ||
643 | elsif No (Ltyp) or else No (Rtyp) then | |
644 | return Unknown; | |
645 | ||
fbf5a39b AC |
646 | -- We only attempt compile time analysis for scalar values, and |
647 | -- not for packed arrays represented as modular types, where the | |
648 | -- semantics of comparison is quite different. | |
996ae0b0 RK |
649 | |
650 | elsif not Is_Scalar_Type (Ltyp) | |
651 | or else Is_Packed_Array_Type (Ltyp) | |
652 | then | |
653 | return Unknown; | |
654 | ||
655 | -- Case where comparison involves two compile time known values | |
656 | ||
657 | elsif Compile_Time_Known_Value (L) | |
658 | and then Compile_Time_Known_Value (R) | |
659 | then | |
660 | -- For the floating-point case, we have to be a little careful, since | |
661 | -- at compile time we are dealing with universal exact values, but at | |
662 | -- runtime, these will be in non-exact target form. That's why the | |
663 | -- returned results are LE and GE below instead of LT and GT. | |
664 | ||
665 | if Is_Floating_Point_Type (Ltyp) | |
666 | or else | |
667 | Is_Floating_Point_Type (Rtyp) | |
668 | then | |
669 | declare | |
670 | Lo : constant Ureal := Expr_Value_R (L); | |
671 | Hi : constant Ureal := Expr_Value_R (R); | |
672 | ||
673 | begin | |
674 | if Lo < Hi then | |
675 | return LE; | |
676 | elsif Lo = Hi then | |
677 | return EQ; | |
678 | else | |
679 | return GE; | |
680 | end if; | |
681 | end; | |
682 | ||
683 | -- For the integer case we know exactly (note that this includes the | |
684 | -- fixed-point case, where we know the run time integer values now) | |
685 | ||
686 | else | |
687 | declare | |
688 | Lo : constant Uint := Expr_Value (L); | |
689 | Hi : constant Uint := Expr_Value (R); | |
690 | ||
691 | begin | |
692 | if Lo < Hi then | |
693 | return LT; | |
694 | elsif Lo = Hi then | |
695 | return EQ; | |
696 | else | |
697 | return GT; | |
698 | end if; | |
699 | end; | |
700 | end if; | |
701 | ||
702 | -- Cases where at least one operand is not known at compile time | |
703 | ||
704 | else | |
705 | -- Here is where we check for comparisons against maximum bounds of | |
706 | -- types, where we know that no value can be outside the bounds of | |
707 | -- the subtype. Note that this routine is allowed to assume that all | |
708 | -- expressions are within their subtype bounds. Callers wishing to | |
709 | -- deal with possibly invalid values must in any case take special | |
710 | -- steps (e.g. conversions to larger types) to avoid this kind of | |
711 | -- optimization, which is always considered to be valid. We do not | |
712 | -- attempt this optimization with generic types, since the type | |
713 | -- bounds may not be meaningful in this case. | |
714 | ||
fbf5a39b AC |
715 | -- We are in danger of an infinite recursion here. It does not seem |
716 | -- useful to go more than one level deep, so the parameter Rec is | |
717 | -- used to protect ourselves against this infinite recursion. | |
718 | ||
719 | if not Rec | |
720 | and then Is_Discrete_Type (Ltyp) | |
721 | and then Is_Discrete_Type (Rtyp) | |
996ae0b0 RK |
722 | and then not Is_Generic_Type (Ltyp) |
723 | and then not Is_Generic_Type (Rtyp) | |
724 | then | |
fbf5a39b AC |
725 | -- See if we can get a decisive check against one operand and |
726 | -- a bound of the other operand (four possible tests here). | |
727 | ||
728 | case Compile_Time_Compare (L, Type_Low_Bound (Rtyp), True) is | |
729 | when LT => return LT; | |
730 | when LE => return LE; | |
731 | when EQ => return LE; | |
732 | when others => null; | |
733 | end case; | |
996ae0b0 | 734 | |
fbf5a39b AC |
735 | case Compile_Time_Compare (L, Type_High_Bound (Rtyp), True) is |
736 | when GT => return GT; | |
737 | when GE => return GE; | |
738 | when EQ => return GE; | |
739 | when others => null; | |
740 | end case; | |
996ae0b0 | 741 | |
fbf5a39b AC |
742 | case Compile_Time_Compare (Type_Low_Bound (Ltyp), R, True) is |
743 | when GT => return GT; | |
744 | when GE => return GE; | |
745 | when EQ => return GE; | |
746 | when others => null; | |
747 | end case; | |
996ae0b0 | 748 | |
fbf5a39b AC |
749 | case Compile_Time_Compare (Type_High_Bound (Ltyp), R, True) is |
750 | when LT => return LT; | |
751 | when LE => return LE; | |
752 | when EQ => return LE; | |
753 | when others => null; | |
754 | end case; | |
996ae0b0 RK |
755 | end if; |
756 | ||
757 | -- Next attempt is to decompose the expressions to extract | |
758 | -- a constant offset resulting from the use of any of the forms: | |
759 | ||
760 | -- expr + literal | |
761 | -- expr - literal | |
762 | -- typ'Succ (expr) | |
763 | -- typ'Pred (expr) | |
764 | ||
765 | -- Then we see if the two expressions are the same value, and if so | |
766 | -- the result is obtained by comparing the offsets. | |
767 | ||
768 | declare | |
769 | Lnode : Node_Id; | |
770 | Loffs : Uint; | |
771 | Rnode : Node_Id; | |
772 | Roffs : Uint; | |
773 | ||
774 | begin | |
775 | Compare_Decompose (L, Lnode, Loffs); | |
776 | Compare_Decompose (R, Rnode, Roffs); | |
777 | ||
778 | if Is_Same_Value (Lnode, Rnode) then | |
779 | if Loffs = Roffs then | |
780 | return EQ; | |
781 | ||
782 | elsif Loffs < Roffs then | |
783 | return LT; | |
784 | ||
785 | else | |
786 | return GT; | |
787 | end if; | |
788 | ||
789 | -- If the expressions are different, we cannot say at compile | |
790 | -- time how they compare, so we return the Unknown indication. | |
791 | ||
792 | else | |
793 | return Unknown; | |
794 | end if; | |
795 | end; | |
796 | end if; | |
797 | end Compile_Time_Compare; | |
798 | ||
f44fe430 RD |
799 | ------------------------------- |
800 | -- Compile_Time_Known_Bounds -- | |
801 | ------------------------------- | |
802 | ||
803 | function Compile_Time_Known_Bounds (T : Entity_Id) return Boolean is | |
804 | Indx : Node_Id; | |
805 | Typ : Entity_Id; | |
806 | ||
807 | begin | |
808 | if not Is_Array_Type (T) then | |
809 | return False; | |
810 | end if; | |
811 | ||
812 | Indx := First_Index (T); | |
813 | while Present (Indx) loop | |
814 | Typ := Underlying_Type (Etype (Indx)); | |
815 | if not Compile_Time_Known_Value (Type_Low_Bound (Typ)) then | |
816 | return False; | |
817 | elsif not Compile_Time_Known_Value (Type_High_Bound (Typ)) then | |
818 | return False; | |
819 | else | |
820 | Next_Index (Indx); | |
821 | end if; | |
822 | end loop; | |
823 | ||
824 | return True; | |
825 | end Compile_Time_Known_Bounds; | |
826 | ||
996ae0b0 RK |
827 | ------------------------------ |
828 | -- Compile_Time_Known_Value -- | |
829 | ------------------------------ | |
830 | ||
831 | function Compile_Time_Known_Value (Op : Node_Id) return Boolean is | |
07fc65c4 GB |
832 | K : constant Node_Kind := Nkind (Op); |
833 | CV_Ent : CV_Entry renames CV_Cache (Nat (Op) mod CV_Cache_Size); | |
996ae0b0 RK |
834 | |
835 | begin | |
836 | -- Never known at compile time if bad type or raises constraint error | |
837 | -- or empty (latter case occurs only as a result of a previous error) | |
838 | ||
839 | if No (Op) | |
840 | or else Op = Error | |
841 | or else Etype (Op) = Any_Type | |
842 | or else Raises_Constraint_Error (Op) | |
843 | then | |
844 | return False; | |
845 | end if; | |
846 | ||
fbf5a39b AC |
847 | -- If this is not a static expression and we are in configurable run |
848 | -- time mode, then we consider it not known at compile time. This | |
849 | -- avoids anomalies where whether something is permitted with a given | |
850 | -- configurable run-time library depends on how good the compiler is | |
851 | -- at optimizing and knowing that things are constant when they | |
852 | -- are non-static. | |
853 | ||
854 | if Configurable_Run_Time_Mode and then not Is_Static_Expression (Op) then | |
855 | return False; | |
856 | end if; | |
857 | ||
996ae0b0 RK |
858 | -- If we have an entity name, then see if it is the name of a constant |
859 | -- and if so, test the corresponding constant value, or the name of | |
860 | -- an enumeration literal, which is always a constant. | |
861 | ||
862 | if Present (Etype (Op)) and then Is_Entity_Name (Op) then | |
863 | declare | |
864 | E : constant Entity_Id := Entity (Op); | |
865 | V : Node_Id; | |
866 | ||
867 | begin | |
868 | -- Never known at compile time if it is a packed array value. | |
869 | -- We might want to try to evaluate these at compile time one | |
870 | -- day, but we do not make that attempt now. | |
871 | ||
872 | if Is_Packed_Array_Type (Etype (Op)) then | |
873 | return False; | |
874 | end if; | |
875 | ||
876 | if Ekind (E) = E_Enumeration_Literal then | |
877 | return True; | |
878 | ||
07fc65c4 | 879 | elsif Ekind (E) = E_Constant then |
996ae0b0 RK |
880 | V := Constant_Value (E); |
881 | return Present (V) and then Compile_Time_Known_Value (V); | |
882 | end if; | |
883 | end; | |
884 | ||
885 | -- We have a value, see if it is compile time known | |
886 | ||
887 | else | |
07fc65c4 | 888 | -- Integer literals are worth storing in the cache |
996ae0b0 | 889 | |
07fc65c4 GB |
890 | if K = N_Integer_Literal then |
891 | CV_Ent.N := Op; | |
892 | CV_Ent.V := Intval (Op); | |
893 | return True; | |
894 | ||
895 | -- Other literals and NULL are known at compile time | |
896 | ||
897 | elsif | |
996ae0b0 RK |
898 | K = N_Character_Literal |
899 | or else | |
900 | K = N_Real_Literal | |
901 | or else | |
902 | K = N_String_Literal | |
903 | or else | |
904 | K = N_Null | |
905 | then | |
906 | return True; | |
907 | ||
908 | -- Any reference to Null_Parameter is known at compile time. No | |
909 | -- other attribute references (that have not already been folded) | |
910 | -- are known at compile time. | |
911 | ||
912 | elsif K = N_Attribute_Reference then | |
913 | return Attribute_Name (Op) = Name_Null_Parameter; | |
07fc65c4 | 914 | end if; |
996ae0b0 | 915 | end if; |
07fc65c4 GB |
916 | |
917 | -- If we fall through, not known at compile time | |
918 | ||
919 | return False; | |
920 | ||
921 | -- If we get an exception while trying to do this test, then some error | |
922 | -- has occurred, and we simply say that the value is not known after all | |
923 | ||
924 | exception | |
925 | when others => | |
926 | return False; | |
996ae0b0 RK |
927 | end Compile_Time_Known_Value; |
928 | ||
929 | -------------------------------------- | |
930 | -- Compile_Time_Known_Value_Or_Aggr -- | |
931 | -------------------------------------- | |
932 | ||
933 | function Compile_Time_Known_Value_Or_Aggr (Op : Node_Id) return Boolean is | |
934 | begin | |
935 | -- If we have an entity name, then see if it is the name of a constant | |
936 | -- and if so, test the corresponding constant value, or the name of | |
937 | -- an enumeration literal, which is always a constant. | |
938 | ||
939 | if Is_Entity_Name (Op) then | |
940 | declare | |
941 | E : constant Entity_Id := Entity (Op); | |
942 | V : Node_Id; | |
943 | ||
944 | begin | |
945 | if Ekind (E) = E_Enumeration_Literal then | |
946 | return True; | |
947 | ||
948 | elsif Ekind (E) /= E_Constant then | |
949 | return False; | |
950 | ||
951 | else | |
952 | V := Constant_Value (E); | |
953 | return Present (V) | |
954 | and then Compile_Time_Known_Value_Or_Aggr (V); | |
955 | end if; | |
956 | end; | |
957 | ||
958 | -- We have a value, see if it is compile time known | |
959 | ||
960 | else | |
961 | if Compile_Time_Known_Value (Op) then | |
962 | return True; | |
963 | ||
964 | elsif Nkind (Op) = N_Aggregate then | |
965 | ||
966 | if Present (Expressions (Op)) then | |
967 | declare | |
968 | Expr : Node_Id; | |
969 | ||
970 | begin | |
971 | Expr := First (Expressions (Op)); | |
972 | while Present (Expr) loop | |
973 | if not Compile_Time_Known_Value_Or_Aggr (Expr) then | |
974 | return False; | |
975 | end if; | |
976 | ||
977 | Next (Expr); | |
978 | end loop; | |
979 | end; | |
980 | end if; | |
981 | ||
982 | if Present (Component_Associations (Op)) then | |
983 | declare | |
984 | Cass : Node_Id; | |
985 | ||
986 | begin | |
987 | Cass := First (Component_Associations (Op)); | |
988 | while Present (Cass) loop | |
989 | if not | |
990 | Compile_Time_Known_Value_Or_Aggr (Expression (Cass)) | |
991 | then | |
992 | return False; | |
993 | end if; | |
994 | ||
995 | Next (Cass); | |
996 | end loop; | |
997 | end; | |
998 | end if; | |
999 | ||
1000 | return True; | |
1001 | ||
1002 | -- All other types of values are not known at compile time | |
1003 | ||
1004 | else | |
1005 | return False; | |
1006 | end if; | |
1007 | ||
1008 | end if; | |
1009 | end Compile_Time_Known_Value_Or_Aggr; | |
1010 | ||
1011 | ----------------- | |
1012 | -- Eval_Actual -- | |
1013 | ----------------- | |
1014 | ||
1015 | -- This is only called for actuals of functions that are not predefined | |
1016 | -- operators (which have already been rewritten as operators at this | |
1017 | -- stage), so the call can never be folded, and all that needs doing for | |
1018 | -- the actual is to do the check for a non-static context. | |
1019 | ||
1020 | procedure Eval_Actual (N : Node_Id) is | |
1021 | begin | |
1022 | Check_Non_Static_Context (N); | |
1023 | end Eval_Actual; | |
1024 | ||
1025 | -------------------- | |
1026 | -- Eval_Allocator -- | |
1027 | -------------------- | |
1028 | ||
1029 | -- Allocators are never static, so all we have to do is to do the | |
1030 | -- check for a non-static context if an expression is present. | |
1031 | ||
1032 | procedure Eval_Allocator (N : Node_Id) is | |
1033 | Expr : constant Node_Id := Expression (N); | |
1034 | ||
1035 | begin | |
1036 | if Nkind (Expr) = N_Qualified_Expression then | |
1037 | Check_Non_Static_Context (Expression (Expr)); | |
1038 | end if; | |
1039 | end Eval_Allocator; | |
1040 | ||
1041 | ------------------------ | |
1042 | -- Eval_Arithmetic_Op -- | |
1043 | ------------------------ | |
1044 | ||
1045 | -- Arithmetic operations are static functions, so the result is static | |
1046 | -- if both operands are static (RM 4.9(7), 4.9(20)). | |
1047 | ||
1048 | procedure Eval_Arithmetic_Op (N : Node_Id) is | |
1049 | Left : constant Node_Id := Left_Opnd (N); | |
1050 | Right : constant Node_Id := Right_Opnd (N); | |
1051 | Ltype : constant Entity_Id := Etype (Left); | |
1052 | Rtype : constant Entity_Id := Etype (Right); | |
1053 | Stat : Boolean; | |
1054 | Fold : Boolean; | |
1055 | ||
1056 | begin | |
1057 | -- If not foldable we are done | |
1058 | ||
1059 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
1060 | ||
1061 | if not Fold then | |
1062 | return; | |
1063 | end if; | |
1064 | ||
1065 | -- Fold for cases where both operands are of integer type | |
1066 | ||
1067 | if Is_Integer_Type (Ltype) and then Is_Integer_Type (Rtype) then | |
1068 | declare | |
1069 | Left_Int : constant Uint := Expr_Value (Left); | |
1070 | Right_Int : constant Uint := Expr_Value (Right); | |
1071 | Result : Uint; | |
1072 | ||
1073 | begin | |
1074 | case Nkind (N) is | |
1075 | ||
1076 | when N_Op_Add => | |
1077 | Result := Left_Int + Right_Int; | |
1078 | ||
1079 | when N_Op_Subtract => | |
1080 | Result := Left_Int - Right_Int; | |
1081 | ||
1082 | when N_Op_Multiply => | |
1083 | if OK_Bits | |
1084 | (N, UI_From_Int | |
1085 | (Num_Bits (Left_Int) + Num_Bits (Right_Int))) | |
1086 | then | |
1087 | Result := Left_Int * Right_Int; | |
1088 | else | |
1089 | Result := Left_Int; | |
1090 | end if; | |
1091 | ||
1092 | when N_Op_Divide => | |
1093 | ||
1094 | -- The exception Constraint_Error is raised by integer | |
1095 | -- division, rem and mod if the right operand is zero. | |
1096 | ||
1097 | if Right_Int = 0 then | |
1098 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
1099 | (N, "division by zero", |
1100 | CE_Divide_By_Zero, | |
1101 | Warn => not Stat); | |
996ae0b0 | 1102 | return; |
fbf5a39b | 1103 | |
996ae0b0 RK |
1104 | else |
1105 | Result := Left_Int / Right_Int; | |
1106 | end if; | |
1107 | ||
1108 | when N_Op_Mod => | |
1109 | ||
1110 | -- The exception Constraint_Error is raised by integer | |
1111 | -- division, rem and mod if the right operand is zero. | |
1112 | ||
1113 | if Right_Int = 0 then | |
1114 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
1115 | (N, "mod with zero divisor", |
1116 | CE_Divide_By_Zero, | |
1117 | Warn => not Stat); | |
996ae0b0 RK |
1118 | return; |
1119 | else | |
1120 | Result := Left_Int mod Right_Int; | |
1121 | end if; | |
1122 | ||
1123 | when N_Op_Rem => | |
1124 | ||
1125 | -- The exception Constraint_Error is raised by integer | |
1126 | -- division, rem and mod if the right operand is zero. | |
1127 | ||
1128 | if Right_Int = 0 then | |
1129 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
1130 | (N, "rem with zero divisor", |
1131 | CE_Divide_By_Zero, | |
1132 | Warn => not Stat); | |
996ae0b0 | 1133 | return; |
fbf5a39b | 1134 | |
996ae0b0 RK |
1135 | else |
1136 | Result := Left_Int rem Right_Int; | |
1137 | end if; | |
1138 | ||
1139 | when others => | |
1140 | raise Program_Error; | |
1141 | end case; | |
1142 | ||
1143 | -- Adjust the result by the modulus if the type is a modular type | |
1144 | ||
1145 | if Is_Modular_Integer_Type (Ltype) then | |
1146 | Result := Result mod Modulus (Ltype); | |
82c80734 RD |
1147 | |
1148 | -- For a signed integer type, check non-static overflow | |
1149 | ||
1150 | elsif (not Stat) and then Is_Signed_Integer_Type (Ltype) then | |
1151 | declare | |
1152 | BT : constant Entity_Id := Base_Type (Ltype); | |
1153 | Lo : constant Uint := Expr_Value (Type_Low_Bound (BT)); | |
1154 | Hi : constant Uint := Expr_Value (Type_High_Bound (BT)); | |
1155 | begin | |
1156 | if Result < Lo or else Result > Hi then | |
1157 | Apply_Compile_Time_Constraint_Error | |
1158 | (N, "value not in range of }?", | |
1159 | CE_Overflow_Check_Failed, | |
1160 | Ent => BT); | |
1161 | return; | |
1162 | end if; | |
1163 | end; | |
996ae0b0 RK |
1164 | end if; |
1165 | ||
82c80734 RD |
1166 | -- If we get here we can fold the result |
1167 | ||
fbf5a39b | 1168 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
1169 | end; |
1170 | ||
1171 | -- Cases where at least one operand is a real. We handle the cases | |
1172 | -- of both reals, or mixed/real integer cases (the latter happen | |
1173 | -- only for divide and multiply, and the result is always real). | |
1174 | ||
1175 | elsif Is_Real_Type (Ltype) or else Is_Real_Type (Rtype) then | |
1176 | declare | |
1177 | Left_Real : Ureal; | |
1178 | Right_Real : Ureal; | |
1179 | Result : Ureal; | |
1180 | ||
1181 | begin | |
1182 | if Is_Real_Type (Ltype) then | |
1183 | Left_Real := Expr_Value_R (Left); | |
1184 | else | |
1185 | Left_Real := UR_From_Uint (Expr_Value (Left)); | |
1186 | end if; | |
1187 | ||
1188 | if Is_Real_Type (Rtype) then | |
1189 | Right_Real := Expr_Value_R (Right); | |
1190 | else | |
1191 | Right_Real := UR_From_Uint (Expr_Value (Right)); | |
1192 | end if; | |
1193 | ||
1194 | if Nkind (N) = N_Op_Add then | |
1195 | Result := Left_Real + Right_Real; | |
1196 | ||
1197 | elsif Nkind (N) = N_Op_Subtract then | |
1198 | Result := Left_Real - Right_Real; | |
1199 | ||
1200 | elsif Nkind (N) = N_Op_Multiply then | |
1201 | Result := Left_Real * Right_Real; | |
1202 | ||
1203 | else pragma Assert (Nkind (N) = N_Op_Divide); | |
1204 | if UR_Is_Zero (Right_Real) then | |
1205 | Apply_Compile_Time_Constraint_Error | |
07fc65c4 | 1206 | (N, "division by zero", CE_Divide_By_Zero); |
996ae0b0 RK |
1207 | return; |
1208 | end if; | |
1209 | ||
1210 | Result := Left_Real / Right_Real; | |
1211 | end if; | |
1212 | ||
fbf5a39b | 1213 | Fold_Ureal (N, Result, Stat); |
996ae0b0 RK |
1214 | end; |
1215 | end if; | |
996ae0b0 RK |
1216 | end Eval_Arithmetic_Op; |
1217 | ||
1218 | ---------------------------- | |
1219 | -- Eval_Character_Literal -- | |
1220 | ---------------------------- | |
1221 | ||
1222 | -- Nothing to be done! | |
1223 | ||
1224 | procedure Eval_Character_Literal (N : Node_Id) is | |
07fc65c4 | 1225 | pragma Warnings (Off, N); |
996ae0b0 RK |
1226 | begin |
1227 | null; | |
1228 | end Eval_Character_Literal; | |
1229 | ||
c01a9391 AC |
1230 | --------------- |
1231 | -- Eval_Call -- | |
1232 | --------------- | |
1233 | ||
1234 | -- Static function calls are either calls to predefined operators | |
1235 | -- with static arguments, or calls to functions that rename a literal. | |
1236 | -- Only the latter case is handled here, predefined operators are | |
1237 | -- constant-folded elsewhere. | |
1238 | -- If the function is itself inherited (see 7423-001) the literal of | |
1239 | -- the parent type must be explicitly converted to the return type | |
1240 | -- of the function. | |
1241 | ||
1242 | procedure Eval_Call (N : Node_Id) is | |
1243 | Loc : constant Source_Ptr := Sloc (N); | |
1244 | Typ : constant Entity_Id := Etype (N); | |
1245 | Lit : Entity_Id; | |
1246 | ||
1247 | begin | |
1248 | if Nkind (N) = N_Function_Call | |
1249 | and then No (Parameter_Associations (N)) | |
1250 | and then Is_Entity_Name (Name (N)) | |
1251 | and then Present (Alias (Entity (Name (N)))) | |
1252 | and then Is_Enumeration_Type (Base_Type (Typ)) | |
1253 | then | |
1254 | Lit := Alias (Entity (Name (N))); | |
1255 | ||
1256 | while Present (Alias (Lit)) loop | |
1257 | Lit := Alias (Lit); | |
1258 | end loop; | |
1259 | ||
1260 | if Ekind (Lit) = E_Enumeration_Literal then | |
1261 | if Base_Type (Etype (Lit)) /= Base_Type (Typ) then | |
1262 | Rewrite | |
1263 | (N, Convert_To (Typ, New_Occurrence_Of (Lit, Loc))); | |
1264 | else | |
1265 | Rewrite (N, New_Occurrence_Of (Lit, Loc)); | |
1266 | end if; | |
1267 | ||
1268 | Resolve (N, Typ); | |
1269 | end if; | |
1270 | end if; | |
1271 | end Eval_Call; | |
1272 | ||
996ae0b0 RK |
1273 | ------------------------ |
1274 | -- Eval_Concatenation -- | |
1275 | ------------------------ | |
1276 | ||
1277 | -- Concatenation is a static function, so the result is static if | |
1278 | -- both operands are static (RM 4.9(7), 4.9(21)). | |
1279 | ||
1280 | procedure Eval_Concatenation (N : Node_Id) is | |
f91b40db GB |
1281 | Left : constant Node_Id := Left_Opnd (N); |
1282 | Right : constant Node_Id := Right_Opnd (N); | |
1283 | C_Typ : constant Entity_Id := Root_Type (Component_Type (Etype (N))); | |
996ae0b0 RK |
1284 | Stat : Boolean; |
1285 | Fold : Boolean; | |
996ae0b0 RK |
1286 | |
1287 | begin | |
1288 | -- Concatenation is never static in Ada 83, so if Ada 83 | |
1289 | -- check operand non-static context | |
1290 | ||
0ab80019 | 1291 | if Ada_Version = Ada_83 |
996ae0b0 RK |
1292 | and then Comes_From_Source (N) |
1293 | then | |
1294 | Check_Non_Static_Context (Left); | |
1295 | Check_Non_Static_Context (Right); | |
1296 | return; | |
1297 | end if; | |
1298 | ||
1299 | -- If not foldable we are done. In principle concatenation that yields | |
1300 | -- any string type is static (i.e. an array type of character types). | |
1301 | -- However, character types can include enumeration literals, and | |
1302 | -- concatenation in that case cannot be described by a literal, so we | |
1303 | -- only consider the operation static if the result is an array of | |
1304 | -- (a descendant of) a predefined character type. | |
1305 | ||
1306 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
1307 | ||
1308 | if (C_Typ = Standard_Character | |
82c80734 RD |
1309 | or else C_Typ = Standard_Wide_Character |
1310 | or else C_Typ = Standard_Wide_Wide_Character) | |
996ae0b0 RK |
1311 | and then Fold |
1312 | then | |
1313 | null; | |
1314 | else | |
1315 | Set_Is_Static_Expression (N, False); | |
1316 | return; | |
1317 | end if; | |
1318 | ||
82c80734 | 1319 | -- Compile time string concatenation |
996ae0b0 RK |
1320 | |
1321 | -- ??? Note that operands that are aggregates can be marked as | |
1322 | -- static, so we should attempt at a later stage to fold | |
1323 | -- concatenations with such aggregates. | |
1324 | ||
1325 | declare | |
1326 | Left_Str : constant Node_Id := Get_String_Val (Left); | |
f91b40db | 1327 | Left_Len : Nat; |
996ae0b0 RK |
1328 | Right_Str : constant Node_Id := Get_String_Val (Right); |
1329 | ||
1330 | begin | |
1331 | -- Establish new string literal, and store left operand. We make | |
1332 | -- sure to use the special Start_String that takes an operand if | |
1333 | -- the left operand is a string literal. Since this is optimized | |
1334 | -- in the case where that is the most recently created string | |
1335 | -- literal, we ensure efficient time/space behavior for the | |
1336 | -- case of a concatenation of a series of string literals. | |
1337 | ||
1338 | if Nkind (Left_Str) = N_String_Literal then | |
f91b40db | 1339 | Left_Len := String_Length (Strval (Left_Str)); |
996ae0b0 RK |
1340 | Start_String (Strval (Left_Str)); |
1341 | else | |
1342 | Start_String; | |
82c80734 | 1343 | Store_String_Char (UI_To_CC (Char_Literal_Value (Left_Str))); |
f91b40db | 1344 | Left_Len := 1; |
996ae0b0 RK |
1345 | end if; |
1346 | ||
1347 | -- Now append the characters of the right operand | |
1348 | ||
1349 | if Nkind (Right_Str) = N_String_Literal then | |
1350 | declare | |
1351 | S : constant String_Id := Strval (Right_Str); | |
1352 | ||
1353 | begin | |
1354 | for J in 1 .. String_Length (S) loop | |
1355 | Store_String_Char (Get_String_Char (S, J)); | |
1356 | end loop; | |
1357 | end; | |
1358 | else | |
82c80734 | 1359 | Store_String_Char (UI_To_CC (Char_Literal_Value (Right_Str))); |
996ae0b0 RK |
1360 | end if; |
1361 | ||
1362 | Set_Is_Static_Expression (N, Stat); | |
1363 | ||
1364 | if Stat then | |
f91b40db GB |
1365 | |
1366 | -- If left operand is the empty string, the result is the | |
1367 | -- right operand, including its bounds if anomalous. | |
1368 | ||
1369 | if Left_Len = 0 | |
1370 | and then Is_Array_Type (Etype (Right)) | |
1371 | and then Etype (Right) /= Any_String | |
1372 | then | |
1373 | Set_Etype (N, Etype (Right)); | |
1374 | end if; | |
1375 | ||
fbf5a39b | 1376 | Fold_Str (N, End_String, True); |
996ae0b0 RK |
1377 | end if; |
1378 | end; | |
1379 | end Eval_Concatenation; | |
1380 | ||
1381 | --------------------------------- | |
1382 | -- Eval_Conditional_Expression -- | |
1383 | --------------------------------- | |
1384 | ||
1385 | -- This GNAT internal construct can never be statically folded, so the | |
1386 | -- only required processing is to do the check for non-static context | |
1387 | -- for the two expression operands. | |
1388 | ||
1389 | procedure Eval_Conditional_Expression (N : Node_Id) is | |
1390 | Condition : constant Node_Id := First (Expressions (N)); | |
1391 | Then_Expr : constant Node_Id := Next (Condition); | |
1392 | Else_Expr : constant Node_Id := Next (Then_Expr); | |
1393 | ||
1394 | begin | |
1395 | Check_Non_Static_Context (Then_Expr); | |
1396 | Check_Non_Static_Context (Else_Expr); | |
1397 | end Eval_Conditional_Expression; | |
1398 | ||
1399 | ---------------------- | |
1400 | -- Eval_Entity_Name -- | |
1401 | ---------------------- | |
1402 | ||
1403 | -- This procedure is used for identifiers and expanded names other than | |
1404 | -- named numbers (see Eval_Named_Integer, Eval_Named_Real. These are | |
1405 | -- static if they denote a static constant (RM 4.9(6)) or if the name | |
1406 | -- denotes an enumeration literal (RM 4.9(22)). | |
1407 | ||
1408 | procedure Eval_Entity_Name (N : Node_Id) is | |
1409 | Def_Id : constant Entity_Id := Entity (N); | |
1410 | Val : Node_Id; | |
1411 | ||
1412 | begin | |
1413 | -- Enumeration literals are always considered to be constants | |
1414 | -- and cannot raise constraint error (RM 4.9(22)). | |
1415 | ||
1416 | if Ekind (Def_Id) = E_Enumeration_Literal then | |
1417 | Set_Is_Static_Expression (N); | |
1418 | return; | |
1419 | ||
1420 | -- A name is static if it denotes a static constant (RM 4.9(5)), and | |
1421 | -- we also copy Raise_Constraint_Error. Notice that even if non-static, | |
1422 | -- it does not violate 10.2.1(8) here, since this is not a variable. | |
1423 | ||
1424 | elsif Ekind (Def_Id) = E_Constant then | |
1425 | ||
1426 | -- Deferred constants must always be treated as nonstatic | |
1427 | -- outside the scope of their full view. | |
1428 | ||
1429 | if Present (Full_View (Def_Id)) | |
1430 | and then not In_Open_Scopes (Scope (Def_Id)) | |
1431 | then | |
1432 | Val := Empty; | |
1433 | else | |
1434 | Val := Constant_Value (Def_Id); | |
1435 | end if; | |
1436 | ||
1437 | if Present (Val) then | |
1438 | Set_Is_Static_Expression | |
1439 | (N, Is_Static_Expression (Val) | |
1440 | and then Is_Static_Subtype (Etype (Def_Id))); | |
1441 | Set_Raises_Constraint_Error (N, Raises_Constraint_Error (Val)); | |
1442 | ||
1443 | if not Is_Static_Expression (N) | |
1444 | and then not Is_Generic_Type (Etype (N)) | |
1445 | then | |
1446 | Validate_Static_Object_Name (N); | |
1447 | end if; | |
1448 | ||
1449 | return; | |
1450 | end if; | |
1451 | end if; | |
1452 | ||
82c80734 | 1453 | -- Fall through if the name is not static |
996ae0b0 RK |
1454 | |
1455 | Validate_Static_Object_Name (N); | |
1456 | end Eval_Entity_Name; | |
1457 | ||
1458 | ---------------------------- | |
1459 | -- Eval_Indexed_Component -- | |
1460 | ---------------------------- | |
1461 | ||
8cbb664e MG |
1462 | -- Indexed components are never static, so we need to perform the check |
1463 | -- for non-static context on the index values. Then, we check if the | |
1464 | -- value can be obtained at compile time, even though it is non-static. | |
996ae0b0 RK |
1465 | |
1466 | procedure Eval_Indexed_Component (N : Node_Id) is | |
1467 | Expr : Node_Id; | |
1468 | ||
1469 | begin | |
fbf5a39b AC |
1470 | -- Check for non-static context on index values |
1471 | ||
996ae0b0 RK |
1472 | Expr := First (Expressions (N)); |
1473 | while Present (Expr) loop | |
1474 | Check_Non_Static_Context (Expr); | |
1475 | Next (Expr); | |
1476 | end loop; | |
1477 | ||
fbf5a39b AC |
1478 | -- If the indexed component appears in an object renaming declaration |
1479 | -- then we do not want to try to evaluate it, since in this case we | |
1480 | -- need the identity of the array element. | |
1481 | ||
1482 | if Nkind (Parent (N)) = N_Object_Renaming_Declaration then | |
1483 | return; | |
1484 | ||
1485 | -- Similarly if the indexed component appears as the prefix of an | |
1486 | -- attribute we don't want to evaluate it, because at least for | |
1487 | -- some cases of attributes we need the identify (e.g. Access, Size) | |
1488 | ||
1489 | elsif Nkind (Parent (N)) = N_Attribute_Reference then | |
1490 | return; | |
1491 | end if; | |
1492 | ||
1493 | -- Note: there are other cases, such as the left side of an assignment, | |
1494 | -- or an OUT parameter for a call, where the replacement results in the | |
1495 | -- illegal use of a constant, But these cases are illegal in the first | |
1496 | -- place, so the replacement, though silly, is harmless. | |
1497 | ||
1498 | -- Now see if this is a constant array reference | |
8cbb664e MG |
1499 | |
1500 | if List_Length (Expressions (N)) = 1 | |
1501 | and then Is_Entity_Name (Prefix (N)) | |
1502 | and then Ekind (Entity (Prefix (N))) = E_Constant | |
1503 | and then Present (Constant_Value (Entity (Prefix (N)))) | |
1504 | then | |
1505 | declare | |
1506 | Loc : constant Source_Ptr := Sloc (N); | |
1507 | Arr : constant Node_Id := Constant_Value (Entity (Prefix (N))); | |
1508 | Sub : constant Node_Id := First (Expressions (N)); | |
1509 | ||
1510 | Atyp : Entity_Id; | |
1511 | -- Type of array | |
1512 | ||
1513 | Lin : Nat; | |
1514 | -- Linear one's origin subscript value for array reference | |
1515 | ||
1516 | Lbd : Node_Id; | |
1517 | -- Lower bound of the first array index | |
1518 | ||
1519 | Elm : Node_Id; | |
1520 | -- Value from constant array | |
1521 | ||
1522 | begin | |
1523 | Atyp := Etype (Arr); | |
1524 | ||
1525 | if Is_Access_Type (Atyp) then | |
1526 | Atyp := Designated_Type (Atyp); | |
1527 | end if; | |
1528 | ||
1529 | -- If we have an array type (we should have but perhaps there | |
1530 | -- are error cases where this is not the case), then see if we | |
1531 | -- can do a constant evaluation of the array reference. | |
1532 | ||
1533 | if Is_Array_Type (Atyp) then | |
1534 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
1535 | Lbd := String_Literal_Low_Bound (Atyp); | |
1536 | else | |
1537 | Lbd := Type_Low_Bound (Etype (First_Index (Atyp))); | |
1538 | end if; | |
1539 | ||
1540 | if Compile_Time_Known_Value (Sub) | |
1541 | and then Nkind (Arr) = N_Aggregate | |
1542 | and then Compile_Time_Known_Value (Lbd) | |
1543 | and then Is_Discrete_Type (Component_Type (Atyp)) | |
1544 | then | |
1545 | Lin := UI_To_Int (Expr_Value (Sub) - Expr_Value (Lbd)) + 1; | |
1546 | ||
1547 | if List_Length (Expressions (Arr)) >= Lin then | |
1548 | Elm := Pick (Expressions (Arr), Lin); | |
1549 | ||
1550 | -- If the resulting expression is compile time known, | |
1551 | -- then we can rewrite the indexed component with this | |
1552 | -- value, being sure to mark the result as non-static. | |
1553 | -- We also reset the Sloc, in case this generates an | |
1554 | -- error later on (e.g. 136'Access). | |
1555 | ||
1556 | if Compile_Time_Known_Value (Elm) then | |
1557 | Rewrite (N, Duplicate_Subexpr_No_Checks (Elm)); | |
1558 | Set_Is_Static_Expression (N, False); | |
1559 | Set_Sloc (N, Loc); | |
1560 | end if; | |
1561 | end if; | |
1562 | end if; | |
1563 | end if; | |
1564 | end; | |
1565 | end if; | |
996ae0b0 RK |
1566 | end Eval_Indexed_Component; |
1567 | ||
1568 | -------------------------- | |
1569 | -- Eval_Integer_Literal -- | |
1570 | -------------------------- | |
1571 | ||
1572 | -- Numeric literals are static (RM 4.9(1)), and have already been marked | |
1573 | -- as static by the analyzer. The reason we did it that early is to allow | |
1574 | -- the possibility of turning off the Is_Static_Expression flag after | |
1575 | -- analysis, but before resolution, when integer literals are generated | |
1576 | -- in the expander that do not correspond to static expressions. | |
1577 | ||
1578 | procedure Eval_Integer_Literal (N : Node_Id) is | |
1579 | T : constant Entity_Id := Etype (N); | |
1580 | ||
5d09245e AC |
1581 | function In_Any_Integer_Context return Boolean; |
1582 | -- If the literal is resolved with a specific type in a context | |
1583 | -- where the expected type is Any_Integer, there are no range checks | |
1584 | -- on the literal. By the time the literal is evaluated, it carries | |
1585 | -- the type imposed by the enclosing expression, and we must recover | |
1586 | -- the context to determine that Any_Integer is meant. | |
1587 | ||
1588 | ---------------------------- | |
1589 | -- To_Any_Integer_Context -- | |
1590 | ---------------------------- | |
1591 | ||
1592 | function In_Any_Integer_Context return Boolean is | |
1593 | Par : constant Node_Id := Parent (N); | |
1594 | K : constant Node_Kind := Nkind (Par); | |
1595 | ||
1596 | begin | |
1597 | -- Any_Integer also appears in digits specifications for real types, | |
1598 | -- but those have bounds smaller that those of any integer base | |
1599 | -- type, so we can safely ignore these cases. | |
1600 | ||
1601 | return K = N_Number_Declaration | |
1602 | or else K = N_Attribute_Reference | |
1603 | or else K = N_Attribute_Definition_Clause | |
1604 | or else K = N_Modular_Type_Definition | |
1605 | or else K = N_Signed_Integer_Type_Definition; | |
1606 | end In_Any_Integer_Context; | |
1607 | ||
1608 | -- Start of processing for Eval_Integer_Literal | |
1609 | ||
996ae0b0 | 1610 | begin |
5d09245e | 1611 | |
996ae0b0 RK |
1612 | -- If the literal appears in a non-expression context, then it is |
1613 | -- certainly appearing in a non-static context, so check it. This | |
1614 | -- is actually a redundant check, since Check_Non_Static_Context | |
1615 | -- would check it, but it seems worth while avoiding the call. | |
1616 | ||
5d09245e AC |
1617 | if Nkind (Parent (N)) not in N_Subexpr |
1618 | and then not In_Any_Integer_Context | |
1619 | then | |
996ae0b0 RK |
1620 | Check_Non_Static_Context (N); |
1621 | end if; | |
1622 | ||
1623 | -- Modular integer literals must be in their base range | |
1624 | ||
1625 | if Is_Modular_Integer_Type (T) | |
1626 | and then Is_Out_Of_Range (N, Base_Type (T)) | |
1627 | then | |
1628 | Out_Of_Range (N); | |
1629 | end if; | |
1630 | end Eval_Integer_Literal; | |
1631 | ||
1632 | --------------------- | |
1633 | -- Eval_Logical_Op -- | |
1634 | --------------------- | |
1635 | ||
1636 | -- Logical operations are static functions, so the result is potentially | |
1637 | -- static if both operands are potentially static (RM 4.9(7), 4.9(20)). | |
1638 | ||
1639 | procedure Eval_Logical_Op (N : Node_Id) is | |
1640 | Left : constant Node_Id := Left_Opnd (N); | |
1641 | Right : constant Node_Id := Right_Opnd (N); | |
1642 | Stat : Boolean; | |
1643 | Fold : Boolean; | |
1644 | ||
1645 | begin | |
1646 | -- If not foldable we are done | |
1647 | ||
1648 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
1649 | ||
1650 | if not Fold then | |
1651 | return; | |
1652 | end if; | |
1653 | ||
1654 | -- Compile time evaluation of logical operation | |
1655 | ||
1656 | declare | |
1657 | Left_Int : constant Uint := Expr_Value (Left); | |
1658 | Right_Int : constant Uint := Expr_Value (Right); | |
1659 | ||
1660 | begin | |
1661 | if Is_Modular_Integer_Type (Etype (N)) then | |
1662 | declare | |
1663 | Left_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1); | |
1664 | Right_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1); | |
1665 | ||
1666 | begin | |
1667 | To_Bits (Left_Int, Left_Bits); | |
1668 | To_Bits (Right_Int, Right_Bits); | |
1669 | ||
1670 | -- Note: should really be able to use array ops instead of | |
1671 | -- these loops, but they weren't working at the time ??? | |
1672 | ||
1673 | if Nkind (N) = N_Op_And then | |
1674 | for J in Left_Bits'Range loop | |
1675 | Left_Bits (J) := Left_Bits (J) and Right_Bits (J); | |
1676 | end loop; | |
1677 | ||
1678 | elsif Nkind (N) = N_Op_Or then | |
1679 | for J in Left_Bits'Range loop | |
1680 | Left_Bits (J) := Left_Bits (J) or Right_Bits (J); | |
1681 | end loop; | |
1682 | ||
1683 | else | |
1684 | pragma Assert (Nkind (N) = N_Op_Xor); | |
1685 | ||
1686 | for J in Left_Bits'Range loop | |
1687 | Left_Bits (J) := Left_Bits (J) xor Right_Bits (J); | |
1688 | end loop; | |
1689 | end if; | |
1690 | ||
fbf5a39b | 1691 | Fold_Uint (N, From_Bits (Left_Bits, Etype (N)), Stat); |
996ae0b0 RK |
1692 | end; |
1693 | ||
1694 | else | |
1695 | pragma Assert (Is_Boolean_Type (Etype (N))); | |
1696 | ||
1697 | if Nkind (N) = N_Op_And then | |
1698 | Fold_Uint (N, | |
fbf5a39b | 1699 | Test (Is_True (Left_Int) and then Is_True (Right_Int)), Stat); |
996ae0b0 RK |
1700 | |
1701 | elsif Nkind (N) = N_Op_Or then | |
1702 | Fold_Uint (N, | |
fbf5a39b | 1703 | Test (Is_True (Left_Int) or else Is_True (Right_Int)), Stat); |
996ae0b0 RK |
1704 | |
1705 | else | |
1706 | pragma Assert (Nkind (N) = N_Op_Xor); | |
1707 | Fold_Uint (N, | |
fbf5a39b | 1708 | Test (Is_True (Left_Int) xor Is_True (Right_Int)), Stat); |
996ae0b0 RK |
1709 | end if; |
1710 | end if; | |
996ae0b0 RK |
1711 | end; |
1712 | end Eval_Logical_Op; | |
1713 | ||
1714 | ------------------------ | |
1715 | -- Eval_Membership_Op -- | |
1716 | ------------------------ | |
1717 | ||
1718 | -- A membership test is potentially static if the expression is static, | |
1719 | -- and the range is a potentially static range, or is a subtype mark | |
1720 | -- denoting a static subtype (RM 4.9(12)). | |
1721 | ||
1722 | procedure Eval_Membership_Op (N : Node_Id) is | |
1723 | Left : constant Node_Id := Left_Opnd (N); | |
1724 | Right : constant Node_Id := Right_Opnd (N); | |
1725 | Def_Id : Entity_Id; | |
1726 | Lo : Node_Id; | |
1727 | Hi : Node_Id; | |
1728 | Result : Boolean; | |
1729 | Stat : Boolean; | |
1730 | Fold : Boolean; | |
1731 | ||
1732 | begin | |
1733 | -- Ignore if error in either operand, except to make sure that | |
1734 | -- Any_Type is properly propagated to avoid junk cascaded errors. | |
1735 | ||
1736 | if Etype (Left) = Any_Type | |
1737 | or else Etype (Right) = Any_Type | |
1738 | then | |
1739 | Set_Etype (N, Any_Type); | |
1740 | return; | |
1741 | end if; | |
1742 | ||
1743 | -- Case of right operand is a subtype name | |
1744 | ||
1745 | if Is_Entity_Name (Right) then | |
1746 | Def_Id := Entity (Right); | |
1747 | ||
1748 | if (Is_Scalar_Type (Def_Id) or else Is_String_Type (Def_Id)) | |
1749 | and then Is_OK_Static_Subtype (Def_Id) | |
1750 | then | |
1751 | Test_Expression_Is_Foldable (N, Left, Stat, Fold); | |
1752 | ||
1753 | if not Fold or else not Stat then | |
1754 | return; | |
1755 | end if; | |
1756 | else | |
1757 | Check_Non_Static_Context (Left); | |
1758 | return; | |
1759 | end if; | |
1760 | ||
1761 | -- For string membership tests we will check the length | |
1762 | -- further below. | |
1763 | ||
1764 | if not Is_String_Type (Def_Id) then | |
1765 | Lo := Type_Low_Bound (Def_Id); | |
1766 | Hi := Type_High_Bound (Def_Id); | |
1767 | ||
1768 | else | |
1769 | Lo := Empty; | |
1770 | Hi := Empty; | |
1771 | end if; | |
1772 | ||
1773 | -- Case of right operand is a range | |
1774 | ||
1775 | else | |
1776 | if Is_Static_Range (Right) then | |
1777 | Test_Expression_Is_Foldable (N, Left, Stat, Fold); | |
1778 | ||
1779 | if not Fold or else not Stat then | |
1780 | return; | |
1781 | ||
1782 | -- If one bound of range raises CE, then don't try to fold | |
1783 | ||
1784 | elsif not Is_OK_Static_Range (Right) then | |
1785 | Check_Non_Static_Context (Left); | |
1786 | return; | |
1787 | end if; | |
1788 | ||
1789 | else | |
1790 | Check_Non_Static_Context (Left); | |
1791 | return; | |
1792 | end if; | |
1793 | ||
1794 | -- Here we know range is an OK static range | |
1795 | ||
1796 | Lo := Low_Bound (Right); | |
1797 | Hi := High_Bound (Right); | |
1798 | end if; | |
1799 | ||
1800 | -- For strings we check that the length of the string expression is | |
1801 | -- compatible with the string subtype if the subtype is constrained, | |
1802 | -- or if unconstrained then the test is always true. | |
1803 | ||
1804 | if Is_String_Type (Etype (Right)) then | |
1805 | if not Is_Constrained (Etype (Right)) then | |
1806 | Result := True; | |
1807 | ||
1808 | else | |
1809 | declare | |
1810 | Typlen : constant Uint := String_Type_Len (Etype (Right)); | |
1811 | Strlen : constant Uint := | |
1812 | UI_From_Int (String_Length (Strval (Get_String_Val (Left)))); | |
1813 | begin | |
1814 | Result := (Typlen = Strlen); | |
1815 | end; | |
1816 | end if; | |
1817 | ||
1818 | -- Fold the membership test. We know we have a static range and Lo | |
1819 | -- and Hi are set to the expressions for the end points of this range. | |
1820 | ||
1821 | elsif Is_Real_Type (Etype (Right)) then | |
1822 | declare | |
1823 | Leftval : constant Ureal := Expr_Value_R (Left); | |
1824 | ||
1825 | begin | |
1826 | Result := Expr_Value_R (Lo) <= Leftval | |
1827 | and then Leftval <= Expr_Value_R (Hi); | |
1828 | end; | |
1829 | ||
1830 | else | |
1831 | declare | |
1832 | Leftval : constant Uint := Expr_Value (Left); | |
1833 | ||
1834 | begin | |
1835 | Result := Expr_Value (Lo) <= Leftval | |
1836 | and then Leftval <= Expr_Value (Hi); | |
1837 | end; | |
1838 | end if; | |
1839 | ||
1840 | if Nkind (N) = N_Not_In then | |
1841 | Result := not Result; | |
1842 | end if; | |
1843 | ||
fbf5a39b | 1844 | Fold_Uint (N, Test (Result), True); |
996ae0b0 | 1845 | Warn_On_Known_Condition (N); |
996ae0b0 RK |
1846 | end Eval_Membership_Op; |
1847 | ||
1848 | ------------------------ | |
1849 | -- Eval_Named_Integer -- | |
1850 | ------------------------ | |
1851 | ||
1852 | procedure Eval_Named_Integer (N : Node_Id) is | |
1853 | begin | |
1854 | Fold_Uint (N, | |
fbf5a39b | 1855 | Expr_Value (Expression (Declaration_Node (Entity (N)))), True); |
996ae0b0 RK |
1856 | end Eval_Named_Integer; |
1857 | ||
1858 | --------------------- | |
1859 | -- Eval_Named_Real -- | |
1860 | --------------------- | |
1861 | ||
1862 | procedure Eval_Named_Real (N : Node_Id) is | |
1863 | begin | |
1864 | Fold_Ureal (N, | |
fbf5a39b | 1865 | Expr_Value_R (Expression (Declaration_Node (Entity (N)))), True); |
996ae0b0 RK |
1866 | end Eval_Named_Real; |
1867 | ||
1868 | ------------------- | |
1869 | -- Eval_Op_Expon -- | |
1870 | ------------------- | |
1871 | ||
1872 | -- Exponentiation is a static functions, so the result is potentially | |
1873 | -- static if both operands are potentially static (RM 4.9(7), 4.9(20)). | |
1874 | ||
1875 | procedure Eval_Op_Expon (N : Node_Id) is | |
1876 | Left : constant Node_Id := Left_Opnd (N); | |
1877 | Right : constant Node_Id := Right_Opnd (N); | |
1878 | Stat : Boolean; | |
1879 | Fold : Boolean; | |
1880 | ||
1881 | begin | |
1882 | -- If not foldable we are done | |
1883 | ||
1884 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
1885 | ||
1886 | if not Fold then | |
1887 | return; | |
1888 | end if; | |
1889 | ||
1890 | -- Fold exponentiation operation | |
1891 | ||
1892 | declare | |
1893 | Right_Int : constant Uint := Expr_Value (Right); | |
1894 | ||
1895 | begin | |
1896 | -- Integer case | |
1897 | ||
1898 | if Is_Integer_Type (Etype (Left)) then | |
1899 | declare | |
1900 | Left_Int : constant Uint := Expr_Value (Left); | |
1901 | Result : Uint; | |
1902 | ||
1903 | begin | |
1904 | -- Exponentiation of an integer raises the exception | |
1905 | -- Constraint_Error for a negative exponent (RM 4.5.6) | |
1906 | ||
1907 | if Right_Int < 0 then | |
1908 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
1909 | (N, "integer exponent negative", |
1910 | CE_Range_Check_Failed, | |
1911 | Warn => not Stat); | |
996ae0b0 RK |
1912 | return; |
1913 | ||
1914 | else | |
1915 | if OK_Bits (N, Num_Bits (Left_Int) * Right_Int) then | |
1916 | Result := Left_Int ** Right_Int; | |
1917 | else | |
1918 | Result := Left_Int; | |
1919 | end if; | |
1920 | ||
1921 | if Is_Modular_Integer_Type (Etype (N)) then | |
1922 | Result := Result mod Modulus (Etype (N)); | |
1923 | end if; | |
1924 | ||
fbf5a39b | 1925 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
1926 | end if; |
1927 | end; | |
1928 | ||
1929 | -- Real case | |
1930 | ||
1931 | else | |
1932 | declare | |
1933 | Left_Real : constant Ureal := Expr_Value_R (Left); | |
1934 | ||
1935 | begin | |
1936 | -- Cannot have a zero base with a negative exponent | |
1937 | ||
1938 | if UR_Is_Zero (Left_Real) then | |
1939 | ||
1940 | if Right_Int < 0 then | |
1941 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
1942 | (N, "zero ** negative integer", |
1943 | CE_Range_Check_Failed, | |
1944 | Warn => not Stat); | |
996ae0b0 RK |
1945 | return; |
1946 | else | |
fbf5a39b | 1947 | Fold_Ureal (N, Ureal_0, Stat); |
996ae0b0 RK |
1948 | end if; |
1949 | ||
1950 | else | |
fbf5a39b | 1951 | Fold_Ureal (N, Left_Real ** Right_Int, Stat); |
996ae0b0 RK |
1952 | end if; |
1953 | end; | |
1954 | end if; | |
996ae0b0 RK |
1955 | end; |
1956 | end Eval_Op_Expon; | |
1957 | ||
1958 | ----------------- | |
1959 | -- Eval_Op_Not -- | |
1960 | ----------------- | |
1961 | ||
1962 | -- The not operation is a static functions, so the result is potentially | |
1963 | -- static if the operand is potentially static (RM 4.9(7), 4.9(20)). | |
1964 | ||
1965 | procedure Eval_Op_Not (N : Node_Id) is | |
1966 | Right : constant Node_Id := Right_Opnd (N); | |
1967 | Stat : Boolean; | |
1968 | Fold : Boolean; | |
1969 | ||
1970 | begin | |
1971 | -- If not foldable we are done | |
1972 | ||
1973 | Test_Expression_Is_Foldable (N, Right, Stat, Fold); | |
1974 | ||
1975 | if not Fold then | |
1976 | return; | |
1977 | end if; | |
1978 | ||
1979 | -- Fold not operation | |
1980 | ||
1981 | declare | |
1982 | Rint : constant Uint := Expr_Value (Right); | |
1983 | Typ : constant Entity_Id := Etype (N); | |
1984 | ||
1985 | begin | |
1986 | -- Negation is equivalent to subtracting from the modulus minus | |
1987 | -- one. For a binary modulus this is equivalent to the ones- | |
1988 | -- component of the original value. For non-binary modulus this | |
1989 | -- is an arbitrary but consistent definition. | |
1990 | ||
1991 | if Is_Modular_Integer_Type (Typ) then | |
fbf5a39b | 1992 | Fold_Uint (N, Modulus (Typ) - 1 - Rint, Stat); |
996ae0b0 RK |
1993 | |
1994 | else | |
1995 | pragma Assert (Is_Boolean_Type (Typ)); | |
fbf5a39b | 1996 | Fold_Uint (N, Test (not Is_True (Rint)), Stat); |
996ae0b0 RK |
1997 | end if; |
1998 | ||
1999 | Set_Is_Static_Expression (N, Stat); | |
2000 | end; | |
2001 | end Eval_Op_Not; | |
2002 | ||
2003 | ------------------------------- | |
2004 | -- Eval_Qualified_Expression -- | |
2005 | ------------------------------- | |
2006 | ||
2007 | -- A qualified expression is potentially static if its subtype mark denotes | |
2008 | -- a static subtype and its expression is potentially static (RM 4.9 (11)). | |
2009 | ||
2010 | procedure Eval_Qualified_Expression (N : Node_Id) is | |
2011 | Operand : constant Node_Id := Expression (N); | |
2012 | Target_Type : constant Entity_Id := Entity (Subtype_Mark (N)); | |
2013 | ||
07fc65c4 GB |
2014 | Stat : Boolean; |
2015 | Fold : Boolean; | |
2016 | Hex : Boolean; | |
996ae0b0 RK |
2017 | |
2018 | begin | |
2019 | -- Can only fold if target is string or scalar and subtype is static | |
2020 | -- Also, do not fold if our parent is an allocator (this is because | |
2021 | -- the qualified expression is really part of the syntactic structure | |
2022 | -- of an allocator, and we do not want to end up with something that | |
2023 | -- corresponds to "new 1" where the 1 is the result of folding a | |
2024 | -- qualified expression). | |
2025 | ||
2026 | if not Is_Static_Subtype (Target_Type) | |
2027 | or else Nkind (Parent (N)) = N_Allocator | |
2028 | then | |
2029 | Check_Non_Static_Context (Operand); | |
af152989 AC |
2030 | |
2031 | -- If operand is known to raise constraint_error, set the | |
2032 | -- flag on the expression so it does not get optimized away. | |
2033 | ||
2034 | if Nkind (Operand) = N_Raise_Constraint_Error then | |
2035 | Set_Raises_Constraint_Error (N); | |
2036 | end if; | |
7324bf49 | 2037 | |
996ae0b0 RK |
2038 | return; |
2039 | end if; | |
2040 | ||
2041 | -- If not foldable we are done | |
2042 | ||
2043 | Test_Expression_Is_Foldable (N, Operand, Stat, Fold); | |
2044 | ||
2045 | if not Fold then | |
2046 | return; | |
2047 | ||
2048 | -- Don't try fold if target type has constraint error bounds | |
2049 | ||
2050 | elsif not Is_OK_Static_Subtype (Target_Type) then | |
2051 | Set_Raises_Constraint_Error (N); | |
2052 | return; | |
2053 | end if; | |
2054 | ||
07fc65c4 GB |
2055 | -- Here we will fold, save Print_In_Hex indication |
2056 | ||
2057 | Hex := Nkind (Operand) = N_Integer_Literal | |
2058 | and then Print_In_Hex (Operand); | |
2059 | ||
996ae0b0 RK |
2060 | -- Fold the result of qualification |
2061 | ||
2062 | if Is_Discrete_Type (Target_Type) then | |
fbf5a39b | 2063 | Fold_Uint (N, Expr_Value (Operand), Stat); |
996ae0b0 | 2064 | |
07fc65c4 GB |
2065 | -- Preserve Print_In_Hex indication |
2066 | ||
2067 | if Hex and then Nkind (N) = N_Integer_Literal then | |
2068 | Set_Print_In_Hex (N); | |
2069 | end if; | |
2070 | ||
996ae0b0 | 2071 | elsif Is_Real_Type (Target_Type) then |
fbf5a39b | 2072 | Fold_Ureal (N, Expr_Value_R (Operand), Stat); |
996ae0b0 RK |
2073 | |
2074 | else | |
fbf5a39b | 2075 | Fold_Str (N, Strval (Get_String_Val (Operand)), Stat); |
996ae0b0 RK |
2076 | |
2077 | if not Stat then | |
2078 | Set_Is_Static_Expression (N, False); | |
2079 | else | |
2080 | Check_String_Literal_Length (N, Target_Type); | |
2081 | end if; | |
2082 | ||
2083 | return; | |
2084 | end if; | |
2085 | ||
fbf5a39b AC |
2086 | -- The expression may be foldable but not static |
2087 | ||
2088 | Set_Is_Static_Expression (N, Stat); | |
2089 | ||
996ae0b0 RK |
2090 | if Is_Out_Of_Range (N, Etype (N)) then |
2091 | Out_Of_Range (N); | |
2092 | end if; | |
996ae0b0 RK |
2093 | end Eval_Qualified_Expression; |
2094 | ||
2095 | ----------------------- | |
2096 | -- Eval_Real_Literal -- | |
2097 | ----------------------- | |
2098 | ||
2099 | -- Numeric literals are static (RM 4.9(1)), and have already been marked | |
2100 | -- as static by the analyzer. The reason we did it that early is to allow | |
2101 | -- the possibility of turning off the Is_Static_Expression flag after | |
2102 | -- analysis, but before resolution, when integer literals are generated | |
2103 | -- in the expander that do not correspond to static expressions. | |
2104 | ||
2105 | procedure Eval_Real_Literal (N : Node_Id) is | |
2106 | begin | |
2107 | -- If the literal appears in a non-expression context, then it is | |
2108 | -- certainly appearing in a non-static context, so check it. | |
2109 | ||
2110 | if Nkind (Parent (N)) not in N_Subexpr then | |
2111 | Check_Non_Static_Context (N); | |
2112 | end if; | |
2113 | ||
2114 | end Eval_Real_Literal; | |
2115 | ||
2116 | ------------------------ | |
2117 | -- Eval_Relational_Op -- | |
2118 | ------------------------ | |
2119 | ||
2120 | -- Relational operations are static functions, so the result is static | |
2121 | -- if both operands are static (RM 4.9(7), 4.9(20)). | |
2122 | ||
2123 | procedure Eval_Relational_Op (N : Node_Id) is | |
2124 | Left : constant Node_Id := Left_Opnd (N); | |
2125 | Right : constant Node_Id := Right_Opnd (N); | |
2126 | Typ : constant Entity_Id := Etype (Left); | |
2127 | Result : Boolean; | |
2128 | Stat : Boolean; | |
2129 | Fold : Boolean; | |
2130 | ||
2131 | begin | |
2132 | -- One special case to deal with first. If we can tell that | |
2133 | -- the result will be false because the lengths of one or | |
2134 | -- more index subtypes are compile time known and different, | |
2135 | -- then we can replace the entire result by False. We only | |
2136 | -- do this for one dimensional arrays, because the case of | |
2137 | -- multi-dimensional arrays is rare and too much trouble! | |
2138 | ||
2139 | if Is_Array_Type (Typ) | |
2140 | and then Number_Dimensions (Typ) = 1 | |
2141 | and then (Nkind (N) = N_Op_Eq | |
2142 | or else Nkind (N) = N_Op_Ne) | |
2143 | then | |
2144 | if Raises_Constraint_Error (Left) | |
2145 | or else Raises_Constraint_Error (Right) | |
2146 | then | |
2147 | return; | |
2148 | end if; | |
2149 | ||
2150 | declare | |
2151 | procedure Get_Static_Length (Op : Node_Id; Len : out Uint); | |
2152 | -- If Op is an expression for a constrained array with a | |
2153 | -- known at compile time length, then Len is set to this | |
2154 | -- (non-negative length). Otherwise Len is set to minus 1. | |
2155 | ||
fbf5a39b AC |
2156 | ----------------------- |
2157 | -- Get_Static_Length -- | |
2158 | ----------------------- | |
2159 | ||
996ae0b0 RK |
2160 | procedure Get_Static_Length (Op : Node_Id; Len : out Uint) is |
2161 | T : Entity_Id; | |
2162 | ||
2163 | begin | |
2164 | if Nkind (Op) = N_String_Literal then | |
2165 | Len := UI_From_Int (String_Length (Strval (Op))); | |
2166 | ||
2167 | elsif not Is_Constrained (Etype (Op)) then | |
2168 | Len := Uint_Minus_1; | |
2169 | ||
2170 | else | |
2171 | T := Etype (First_Index (Etype (Op))); | |
2172 | ||
2173 | if Is_Discrete_Type (T) | |
2174 | and then | |
2175 | Compile_Time_Known_Value (Type_Low_Bound (T)) | |
2176 | and then | |
2177 | Compile_Time_Known_Value (Type_High_Bound (T)) | |
2178 | then | |
2179 | Len := UI_Max (Uint_0, | |
2180 | Expr_Value (Type_High_Bound (T)) - | |
2181 | Expr_Value (Type_Low_Bound (T)) + 1); | |
2182 | else | |
2183 | Len := Uint_Minus_1; | |
2184 | end if; | |
2185 | end if; | |
2186 | end Get_Static_Length; | |
2187 | ||
2188 | Len_L : Uint; | |
2189 | Len_R : Uint; | |
2190 | ||
2191 | begin | |
2192 | Get_Static_Length (Left, Len_L); | |
2193 | Get_Static_Length (Right, Len_R); | |
2194 | ||
2195 | if Len_L /= Uint_Minus_1 | |
2196 | and then Len_R /= Uint_Minus_1 | |
2197 | and then Len_L /= Len_R | |
2198 | then | |
fbf5a39b | 2199 | Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False); |
996ae0b0 RK |
2200 | Warn_On_Known_Condition (N); |
2201 | return; | |
2202 | end if; | |
2203 | end; | |
6eaf4095 ES |
2204 | |
2205 | -- Another special case: comparisons against null for pointers that | |
2206 | -- are known to be non-null. This is useful when migrating from Ada95 | |
2207 | -- code when non-null restrictions are added to type declarations and | |
2208 | -- parameter specifications. | |
2209 | ||
2210 | elsif Is_Access_Type (Typ) | |
2211 | and then Comes_From_Source (N) | |
2212 | and then | |
2213 | ((Is_Entity_Name (Left) | |
2214 | and then Is_Known_Non_Null (Entity (Left)) | |
2215 | and then Nkind (Right) = N_Null) | |
2216 | or else | |
2217 | (Is_Entity_Name (Right) | |
2218 | and then Is_Known_Non_Null (Entity (Right)) | |
2219 | and then Nkind (Left) = N_Null)) | |
2220 | then | |
2221 | Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False); | |
2222 | Warn_On_Known_Condition (N); | |
2223 | return; | |
996ae0b0 RK |
2224 | end if; |
2225 | ||
2226 | -- Can only fold if type is scalar (don't fold string ops) | |
2227 | ||
2228 | if not Is_Scalar_Type (Typ) then | |
2229 | Check_Non_Static_Context (Left); | |
2230 | Check_Non_Static_Context (Right); | |
2231 | return; | |
2232 | end if; | |
2233 | ||
2234 | -- If not foldable we are done | |
2235 | ||
2236 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
2237 | ||
2238 | if not Fold then | |
2239 | return; | |
2240 | end if; | |
2241 | ||
2242 | -- Integer and Enumeration (discrete) type cases | |
2243 | ||
2244 | if Is_Discrete_Type (Typ) then | |
2245 | declare | |
2246 | Left_Int : constant Uint := Expr_Value (Left); | |
2247 | Right_Int : constant Uint := Expr_Value (Right); | |
2248 | ||
2249 | begin | |
2250 | case Nkind (N) is | |
2251 | when N_Op_Eq => Result := Left_Int = Right_Int; | |
2252 | when N_Op_Ne => Result := Left_Int /= Right_Int; | |
2253 | when N_Op_Lt => Result := Left_Int < Right_Int; | |
2254 | when N_Op_Le => Result := Left_Int <= Right_Int; | |
2255 | when N_Op_Gt => Result := Left_Int > Right_Int; | |
2256 | when N_Op_Ge => Result := Left_Int >= Right_Int; | |
2257 | ||
2258 | when others => | |
2259 | raise Program_Error; | |
2260 | end case; | |
2261 | ||
fbf5a39b | 2262 | Fold_Uint (N, Test (Result), Stat); |
996ae0b0 RK |
2263 | end; |
2264 | ||
2265 | -- Real type case | |
2266 | ||
2267 | else | |
2268 | pragma Assert (Is_Real_Type (Typ)); | |
2269 | ||
2270 | declare | |
2271 | Left_Real : constant Ureal := Expr_Value_R (Left); | |
2272 | Right_Real : constant Ureal := Expr_Value_R (Right); | |
2273 | ||
2274 | begin | |
2275 | case Nkind (N) is | |
2276 | when N_Op_Eq => Result := (Left_Real = Right_Real); | |
2277 | when N_Op_Ne => Result := (Left_Real /= Right_Real); | |
2278 | when N_Op_Lt => Result := (Left_Real < Right_Real); | |
2279 | when N_Op_Le => Result := (Left_Real <= Right_Real); | |
2280 | when N_Op_Gt => Result := (Left_Real > Right_Real); | |
2281 | when N_Op_Ge => Result := (Left_Real >= Right_Real); | |
2282 | ||
2283 | when others => | |
2284 | raise Program_Error; | |
2285 | end case; | |
2286 | ||
fbf5a39b | 2287 | Fold_Uint (N, Test (Result), Stat); |
996ae0b0 RK |
2288 | end; |
2289 | end if; | |
2290 | ||
996ae0b0 RK |
2291 | Warn_On_Known_Condition (N); |
2292 | end Eval_Relational_Op; | |
2293 | ||
2294 | ---------------- | |
2295 | -- Eval_Shift -- | |
2296 | ---------------- | |
2297 | ||
2298 | -- Shift operations are intrinsic operations that can never be static, | |
2299 | -- so the only processing required is to perform the required check for | |
2300 | -- a non static context for the two operands. | |
2301 | ||
2302 | -- Actually we could do some compile time evaluation here some time ??? | |
2303 | ||
2304 | procedure Eval_Shift (N : Node_Id) is | |
2305 | begin | |
2306 | Check_Non_Static_Context (Left_Opnd (N)); | |
2307 | Check_Non_Static_Context (Right_Opnd (N)); | |
2308 | end Eval_Shift; | |
2309 | ||
2310 | ------------------------ | |
2311 | -- Eval_Short_Circuit -- | |
2312 | ------------------------ | |
2313 | ||
2314 | -- A short circuit operation is potentially static if both operands | |
2315 | -- are potentially static (RM 4.9 (13)) | |
2316 | ||
2317 | procedure Eval_Short_Circuit (N : Node_Id) is | |
2318 | Kind : constant Node_Kind := Nkind (N); | |
2319 | Left : constant Node_Id := Left_Opnd (N); | |
2320 | Right : constant Node_Id := Right_Opnd (N); | |
2321 | Left_Int : Uint; | |
2322 | Rstat : constant Boolean := | |
2323 | Is_Static_Expression (Left) | |
2324 | and then Is_Static_Expression (Right); | |
2325 | ||
2326 | begin | |
2327 | -- Short circuit operations are never static in Ada 83 | |
2328 | ||
0ab80019 | 2329 | if Ada_Version = Ada_83 |
996ae0b0 RK |
2330 | and then Comes_From_Source (N) |
2331 | then | |
2332 | Check_Non_Static_Context (Left); | |
2333 | Check_Non_Static_Context (Right); | |
2334 | return; | |
2335 | end if; | |
2336 | ||
2337 | -- Now look at the operands, we can't quite use the normal call to | |
2338 | -- Test_Expression_Is_Foldable here because short circuit operations | |
2339 | -- are a special case, they can still be foldable, even if the right | |
2340 | -- operand raises constraint error. | |
2341 | ||
2342 | -- If either operand is Any_Type, just propagate to result and | |
2343 | -- do not try to fold, this prevents cascaded errors. | |
2344 | ||
2345 | if Etype (Left) = Any_Type or else Etype (Right) = Any_Type then | |
2346 | Set_Etype (N, Any_Type); | |
2347 | return; | |
2348 | ||
2349 | -- If left operand raises constraint error, then replace node N with | |
2350 | -- the raise constraint error node, and we are obviously not foldable. | |
2351 | -- Is_Static_Expression is set from the two operands in the normal way, | |
2352 | -- and we check the right operand if it is in a non-static context. | |
2353 | ||
2354 | elsif Raises_Constraint_Error (Left) then | |
2355 | if not Rstat then | |
2356 | Check_Non_Static_Context (Right); | |
2357 | end if; | |
2358 | ||
2359 | Rewrite_In_Raise_CE (N, Left); | |
2360 | Set_Is_Static_Expression (N, Rstat); | |
2361 | return; | |
2362 | ||
2363 | -- If the result is not static, then we won't in any case fold | |
2364 | ||
2365 | elsif not Rstat then | |
2366 | Check_Non_Static_Context (Left); | |
2367 | Check_Non_Static_Context (Right); | |
2368 | return; | |
2369 | end if; | |
2370 | ||
2371 | -- Here the result is static, note that, unlike the normal processing | |
2372 | -- in Test_Expression_Is_Foldable, we did *not* check above to see if | |
2373 | -- the right operand raises constraint error, that's because it is not | |
2374 | -- significant if the left operand is decisive. | |
2375 | ||
2376 | Set_Is_Static_Expression (N); | |
2377 | ||
2378 | -- It does not matter if the right operand raises constraint error if | |
2379 | -- it will not be evaluated. So deal specially with the cases where | |
2380 | -- the right operand is not evaluated. Note that we will fold these | |
2381 | -- cases even if the right operand is non-static, which is fine, but | |
2382 | -- of course in these cases the result is not potentially static. | |
2383 | ||
2384 | Left_Int := Expr_Value (Left); | |
2385 | ||
2386 | if (Kind = N_And_Then and then Is_False (Left_Int)) | |
2387 | or else (Kind = N_Or_Else and Is_True (Left_Int)) | |
2388 | then | |
fbf5a39b | 2389 | Fold_Uint (N, Left_Int, Rstat); |
996ae0b0 RK |
2390 | return; |
2391 | end if; | |
2392 | ||
2393 | -- If first operand not decisive, then it does matter if the right | |
2394 | -- operand raises constraint error, since it will be evaluated, so | |
2395 | -- we simply replace the node with the right operand. Note that this | |
2396 | -- properly propagates Is_Static_Expression and Raises_Constraint_Error | |
2397 | -- (both are set to True in Right). | |
2398 | ||
2399 | if Raises_Constraint_Error (Right) then | |
2400 | Rewrite_In_Raise_CE (N, Right); | |
2401 | Check_Non_Static_Context (Left); | |
2402 | return; | |
2403 | end if; | |
2404 | ||
2405 | -- Otherwise the result depends on the right operand | |
2406 | ||
fbf5a39b | 2407 | Fold_Uint (N, Expr_Value (Right), Rstat); |
996ae0b0 | 2408 | return; |
996ae0b0 RK |
2409 | end Eval_Short_Circuit; |
2410 | ||
2411 | ---------------- | |
2412 | -- Eval_Slice -- | |
2413 | ---------------- | |
2414 | ||
2415 | -- Slices can never be static, so the only processing required is to | |
2416 | -- check for non-static context if an explicit range is given. | |
2417 | ||
2418 | procedure Eval_Slice (N : Node_Id) is | |
2419 | Drange : constant Node_Id := Discrete_Range (N); | |
2420 | ||
2421 | begin | |
2422 | if Nkind (Drange) = N_Range then | |
2423 | Check_Non_Static_Context (Low_Bound (Drange)); | |
2424 | Check_Non_Static_Context (High_Bound (Drange)); | |
2425 | end if; | |
2426 | end Eval_Slice; | |
2427 | ||
2428 | ------------------------- | |
2429 | -- Eval_String_Literal -- | |
2430 | ------------------------- | |
2431 | ||
2432 | procedure Eval_String_Literal (N : Node_Id) is | |
91b1417d AC |
2433 | Typ : constant Entity_Id := Etype (N); |
2434 | Bas : constant Entity_Id := Base_Type (Typ); | |
2435 | Xtp : Entity_Id; | |
2436 | Len : Nat; | |
2437 | Lo : Node_Id; | |
996ae0b0 RK |
2438 | |
2439 | begin | |
2440 | -- Nothing to do if error type (handles cases like default expressions | |
2441 | -- or generics where we have not yet fully resolved the type) | |
2442 | ||
91b1417d | 2443 | if Bas = Any_Type or else Bas = Any_String then |
996ae0b0 | 2444 | return; |
91b1417d | 2445 | end if; |
996ae0b0 RK |
2446 | |
2447 | -- String literals are static if the subtype is static (RM 4.9(2)), so | |
2448 | -- reset the static expression flag (it was set unconditionally in | |
2449 | -- Analyze_String_Literal) if the subtype is non-static. We tell if | |
2450 | -- the subtype is static by looking at the lower bound. | |
2451 | ||
91b1417d AC |
2452 | if Ekind (Typ) = E_String_Literal_Subtype then |
2453 | if not Is_OK_Static_Expression (String_Literal_Low_Bound (Typ)) then | |
2454 | Set_Is_Static_Expression (N, False); | |
2455 | return; | |
2456 | end if; | |
2457 | ||
2458 | -- Here if Etype of string literal is normal Etype (not yet possible, | |
2459 | -- but may be possible in future!) | |
2460 | ||
2461 | elsif not Is_OK_Static_Expression | |
2462 | (Type_Low_Bound (Etype (First_Index (Typ)))) | |
2463 | then | |
996ae0b0 | 2464 | Set_Is_Static_Expression (N, False); |
91b1417d AC |
2465 | return; |
2466 | end if; | |
996ae0b0 | 2467 | |
91b1417d AC |
2468 | -- If original node was a type conversion, then result if non-static |
2469 | ||
2470 | if Nkind (Original_Node (N)) = N_Type_Conversion then | |
996ae0b0 | 2471 | Set_Is_Static_Expression (N, False); |
91b1417d AC |
2472 | return; |
2473 | end if; | |
996ae0b0 RK |
2474 | |
2475 | -- Test for illegal Ada 95 cases. A string literal is illegal in | |
2476 | -- Ada 95 if its bounds are outside the index base type and this | |
91b1417d | 2477 | -- index type is static. This can happen in only two ways. Either |
996ae0b0 RK |
2478 | -- the string literal is too long, or it is null, and the lower |
2479 | -- bound is type'First. In either case it is the upper bound that | |
2480 | -- is out of range of the index type. | |
2481 | ||
0ab80019 | 2482 | if Ada_Version >= Ada_95 then |
91b1417d AC |
2483 | if Root_Type (Bas) = Standard_String |
2484 | or else | |
2485 | Root_Type (Bas) = Standard_Wide_String | |
996ae0b0 | 2486 | then |
91b1417d | 2487 | Xtp := Standard_Positive; |
996ae0b0 | 2488 | else |
91b1417d | 2489 | Xtp := Etype (First_Index (Bas)); |
996ae0b0 RK |
2490 | end if; |
2491 | ||
91b1417d AC |
2492 | if Ekind (Typ) = E_String_Literal_Subtype then |
2493 | Lo := String_Literal_Low_Bound (Typ); | |
2494 | else | |
2495 | Lo := Type_Low_Bound (Etype (First_Index (Typ))); | |
2496 | end if; | |
2497 | ||
2498 | Len := String_Length (Strval (N)); | |
2499 | ||
2500 | if UI_From_Int (Len) > String_Type_Len (Bas) then | |
996ae0b0 | 2501 | Apply_Compile_Time_Constraint_Error |
07fc65c4 | 2502 | (N, "string literal too long for}", CE_Length_Check_Failed, |
91b1417d AC |
2503 | Ent => Bas, |
2504 | Typ => First_Subtype (Bas)); | |
996ae0b0 | 2505 | |
91b1417d AC |
2506 | elsif Len = 0 |
2507 | and then not Is_Generic_Type (Xtp) | |
2508 | and then | |
2509 | Expr_Value (Lo) = Expr_Value (Type_Low_Bound (Base_Type (Xtp))) | |
996ae0b0 RK |
2510 | then |
2511 | Apply_Compile_Time_Constraint_Error | |
2512 | (N, "null string literal not allowed for}", | |
07fc65c4 | 2513 | CE_Length_Check_Failed, |
91b1417d AC |
2514 | Ent => Bas, |
2515 | Typ => First_Subtype (Bas)); | |
996ae0b0 RK |
2516 | end if; |
2517 | end if; | |
996ae0b0 RK |
2518 | end Eval_String_Literal; |
2519 | ||
2520 | -------------------------- | |
2521 | -- Eval_Type_Conversion -- | |
2522 | -------------------------- | |
2523 | ||
2524 | -- A type conversion is potentially static if its subtype mark is for a | |
2525 | -- static scalar subtype, and its operand expression is potentially static | |
2526 | -- (RM 4.9 (10)) | |
2527 | ||
2528 | procedure Eval_Type_Conversion (N : Node_Id) is | |
2529 | Operand : constant Node_Id := Expression (N); | |
2530 | Source_Type : constant Entity_Id := Etype (Operand); | |
2531 | Target_Type : constant Entity_Id := Etype (N); | |
2532 | ||
2533 | Stat : Boolean; | |
2534 | Fold : Boolean; | |
2535 | ||
2536 | function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean; | |
2537 | -- Returns true if type T is an integer type, or if it is a | |
2538 | -- fixed-point type to be treated as an integer (i.e. the flag | |
2539 | -- Conversion_OK is set on the conversion node). | |
2540 | ||
2541 | function To_Be_Treated_As_Real (T : Entity_Id) return Boolean; | |
2542 | -- Returns true if type T is a floating-point type, or if it is a | |
2543 | -- fixed-point type that is not to be treated as an integer (i.e. the | |
2544 | -- flag Conversion_OK is not set on the conversion node). | |
2545 | ||
fbf5a39b AC |
2546 | ------------------------------ |
2547 | -- To_Be_Treated_As_Integer -- | |
2548 | ------------------------------ | |
2549 | ||
996ae0b0 RK |
2550 | function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean is |
2551 | begin | |
2552 | return | |
2553 | Is_Integer_Type (T) | |
2554 | or else (Is_Fixed_Point_Type (T) and then Conversion_OK (N)); | |
2555 | end To_Be_Treated_As_Integer; | |
2556 | ||
fbf5a39b AC |
2557 | --------------------------- |
2558 | -- To_Be_Treated_As_Real -- | |
2559 | --------------------------- | |
2560 | ||
996ae0b0 RK |
2561 | function To_Be_Treated_As_Real (T : Entity_Id) return Boolean is |
2562 | begin | |
2563 | return | |
2564 | Is_Floating_Point_Type (T) | |
2565 | or else (Is_Fixed_Point_Type (T) and then not Conversion_OK (N)); | |
2566 | end To_Be_Treated_As_Real; | |
2567 | ||
2568 | -- Start of processing for Eval_Type_Conversion | |
2569 | ||
2570 | begin | |
82c80734 | 2571 | -- Cannot fold if target type is non-static or if semantic error |
996ae0b0 RK |
2572 | |
2573 | if not Is_Static_Subtype (Target_Type) then | |
2574 | Check_Non_Static_Context (Operand); | |
2575 | return; | |
2576 | ||
2577 | elsif Error_Posted (N) then | |
2578 | return; | |
2579 | end if; | |
2580 | ||
2581 | -- If not foldable we are done | |
2582 | ||
2583 | Test_Expression_Is_Foldable (N, Operand, Stat, Fold); | |
2584 | ||
2585 | if not Fold then | |
2586 | return; | |
2587 | ||
2588 | -- Don't try fold if target type has constraint error bounds | |
2589 | ||
2590 | elsif not Is_OK_Static_Subtype (Target_Type) then | |
2591 | Set_Raises_Constraint_Error (N); | |
2592 | return; | |
2593 | end if; | |
2594 | ||
2595 | -- Remaining processing depends on operand types. Note that in the | |
2596 | -- following type test, fixed-point counts as real unless the flag | |
2597 | -- Conversion_OK is set, in which case it counts as integer. | |
2598 | ||
82c80734 | 2599 | -- Fold conversion, case of string type. The result is not static |
996ae0b0 RK |
2600 | |
2601 | if Is_String_Type (Target_Type) then | |
fbf5a39b | 2602 | Fold_Str (N, Strval (Get_String_Val (Operand)), False); |
996ae0b0 RK |
2603 | |
2604 | return; | |
2605 | ||
2606 | -- Fold conversion, case of integer target type | |
2607 | ||
2608 | elsif To_Be_Treated_As_Integer (Target_Type) then | |
2609 | declare | |
2610 | Result : Uint; | |
2611 | ||
2612 | begin | |
2613 | -- Integer to integer conversion | |
2614 | ||
2615 | if To_Be_Treated_As_Integer (Source_Type) then | |
2616 | Result := Expr_Value (Operand); | |
2617 | ||
2618 | -- Real to integer conversion | |
2619 | ||
2620 | else | |
2621 | Result := UR_To_Uint (Expr_Value_R (Operand)); | |
2622 | end if; | |
2623 | ||
2624 | -- If fixed-point type (Conversion_OK must be set), then the | |
2625 | -- result is logically an integer, but we must replace the | |
2626 | -- conversion with the corresponding real literal, since the | |
2627 | -- type from a semantic point of view is still fixed-point. | |
2628 | ||
2629 | if Is_Fixed_Point_Type (Target_Type) then | |
2630 | Fold_Ureal | |
fbf5a39b | 2631 | (N, UR_From_Uint (Result) * Small_Value (Target_Type), Stat); |
996ae0b0 RK |
2632 | |
2633 | -- Otherwise result is integer literal | |
2634 | ||
2635 | else | |
fbf5a39b | 2636 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
2637 | end if; |
2638 | end; | |
2639 | ||
2640 | -- Fold conversion, case of real target type | |
2641 | ||
2642 | elsif To_Be_Treated_As_Real (Target_Type) then | |
2643 | declare | |
2644 | Result : Ureal; | |
2645 | ||
2646 | begin | |
2647 | if To_Be_Treated_As_Real (Source_Type) then | |
2648 | Result := Expr_Value_R (Operand); | |
2649 | else | |
2650 | Result := UR_From_Uint (Expr_Value (Operand)); | |
2651 | end if; | |
2652 | ||
fbf5a39b | 2653 | Fold_Ureal (N, Result, Stat); |
996ae0b0 RK |
2654 | end; |
2655 | ||
2656 | -- Enumeration types | |
2657 | ||
2658 | else | |
fbf5a39b | 2659 | Fold_Uint (N, Expr_Value (Operand), Stat); |
996ae0b0 RK |
2660 | end if; |
2661 | ||
996ae0b0 RK |
2662 | if Is_Out_Of_Range (N, Etype (N)) then |
2663 | Out_Of_Range (N); | |
2664 | end if; | |
2665 | ||
2666 | end Eval_Type_Conversion; | |
2667 | ||
2668 | ------------------- | |
2669 | -- Eval_Unary_Op -- | |
2670 | ------------------- | |
2671 | ||
2672 | -- Predefined unary operators are static functions (RM 4.9(20)) and thus | |
2673 | -- are potentially static if the operand is potentially static (RM 4.9(7)) | |
2674 | ||
2675 | procedure Eval_Unary_Op (N : Node_Id) is | |
2676 | Right : constant Node_Id := Right_Opnd (N); | |
2677 | Stat : Boolean; | |
2678 | Fold : Boolean; | |
2679 | ||
2680 | begin | |
2681 | -- If not foldable we are done | |
2682 | ||
2683 | Test_Expression_Is_Foldable (N, Right, Stat, Fold); | |
2684 | ||
2685 | if not Fold then | |
2686 | return; | |
2687 | end if; | |
2688 | ||
2689 | -- Fold for integer case | |
2690 | ||
2691 | if Is_Integer_Type (Etype (N)) then | |
2692 | declare | |
2693 | Rint : constant Uint := Expr_Value (Right); | |
2694 | Result : Uint; | |
2695 | ||
2696 | begin | |
2697 | -- In the case of modular unary plus and abs there is no need | |
2698 | -- to adjust the result of the operation since if the original | |
2699 | -- operand was in bounds the result will be in the bounds of the | |
2700 | -- modular type. However, in the case of modular unary minus the | |
2701 | -- result may go out of the bounds of the modular type and needs | |
2702 | -- adjustment. | |
2703 | ||
2704 | if Nkind (N) = N_Op_Plus then | |
2705 | Result := Rint; | |
2706 | ||
2707 | elsif Nkind (N) = N_Op_Minus then | |
2708 | if Is_Modular_Integer_Type (Etype (N)) then | |
2709 | Result := (-Rint) mod Modulus (Etype (N)); | |
2710 | else | |
2711 | Result := (-Rint); | |
2712 | end if; | |
2713 | ||
2714 | else | |
2715 | pragma Assert (Nkind (N) = N_Op_Abs); | |
2716 | Result := abs Rint; | |
2717 | end if; | |
2718 | ||
fbf5a39b | 2719 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
2720 | end; |
2721 | ||
2722 | -- Fold for real case | |
2723 | ||
2724 | elsif Is_Real_Type (Etype (N)) then | |
2725 | declare | |
2726 | Rreal : constant Ureal := Expr_Value_R (Right); | |
2727 | Result : Ureal; | |
2728 | ||
2729 | begin | |
2730 | if Nkind (N) = N_Op_Plus then | |
2731 | Result := Rreal; | |
2732 | ||
2733 | elsif Nkind (N) = N_Op_Minus then | |
2734 | Result := UR_Negate (Rreal); | |
2735 | ||
2736 | else | |
2737 | pragma Assert (Nkind (N) = N_Op_Abs); | |
2738 | Result := abs Rreal; | |
2739 | end if; | |
2740 | ||
fbf5a39b | 2741 | Fold_Ureal (N, Result, Stat); |
996ae0b0 RK |
2742 | end; |
2743 | end if; | |
996ae0b0 RK |
2744 | end Eval_Unary_Op; |
2745 | ||
2746 | ------------------------------- | |
2747 | -- Eval_Unchecked_Conversion -- | |
2748 | ------------------------------- | |
2749 | ||
2750 | -- Unchecked conversions can never be static, so the only required | |
2751 | -- processing is to check for a non-static context for the operand. | |
2752 | ||
2753 | procedure Eval_Unchecked_Conversion (N : Node_Id) is | |
2754 | begin | |
2755 | Check_Non_Static_Context (Expression (N)); | |
2756 | end Eval_Unchecked_Conversion; | |
2757 | ||
2758 | -------------------- | |
2759 | -- Expr_Rep_Value -- | |
2760 | -------------------- | |
2761 | ||
2762 | function Expr_Rep_Value (N : Node_Id) return Uint is | |
07fc65c4 GB |
2763 | Kind : constant Node_Kind := Nkind (N); |
2764 | Ent : Entity_Id; | |
996ae0b0 RK |
2765 | |
2766 | begin | |
2767 | if Is_Entity_Name (N) then | |
2768 | Ent := Entity (N); | |
2769 | ||
2770 | -- An enumeration literal that was either in the source or | |
2771 | -- created as a result of static evaluation. | |
2772 | ||
2773 | if Ekind (Ent) = E_Enumeration_Literal then | |
2774 | return Enumeration_Rep (Ent); | |
2775 | ||
2776 | -- A user defined static constant | |
2777 | ||
2778 | else | |
2779 | pragma Assert (Ekind (Ent) = E_Constant); | |
2780 | return Expr_Rep_Value (Constant_Value (Ent)); | |
2781 | end if; | |
2782 | ||
2783 | -- An integer literal that was either in the source or created | |
2784 | -- as a result of static evaluation. | |
2785 | ||
2786 | elsif Kind = N_Integer_Literal then | |
2787 | return Intval (N); | |
2788 | ||
2789 | -- A real literal for a fixed-point type. This must be the fixed-point | |
2790 | -- case, either the literal is of a fixed-point type, or it is a bound | |
2791 | -- of a fixed-point type, with type universal real. In either case we | |
2792 | -- obtain the desired value from Corresponding_Integer_Value. | |
2793 | ||
2794 | elsif Kind = N_Real_Literal then | |
996ae0b0 RK |
2795 | pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N)))); |
2796 | return Corresponding_Integer_Value (N); | |
2797 | ||
07fc65c4 GB |
2798 | -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero |
2799 | ||
2800 | elsif Kind = N_Attribute_Reference | |
2801 | and then Attribute_Name (N) = Name_Null_Parameter | |
2802 | then | |
2803 | return Uint_0; | |
2804 | ||
07fc65c4 | 2805 | -- Otherwise must be character literal |
8cbb664e | 2806 | |
996ae0b0 RK |
2807 | else |
2808 | pragma Assert (Kind = N_Character_Literal); | |
2809 | Ent := Entity (N); | |
2810 | ||
2811 | -- Since Character literals of type Standard.Character don't | |
2812 | -- have any defining character literals built for them, they | |
2813 | -- do not have their Entity set, so just use their Char | |
2814 | -- code. Otherwise for user-defined character literals use | |
2815 | -- their Pos value as usual which is the same as the Rep value. | |
2816 | ||
2817 | if No (Ent) then | |
82c80734 | 2818 | return Char_Literal_Value (N); |
996ae0b0 RK |
2819 | else |
2820 | return Enumeration_Rep (Ent); | |
2821 | end if; | |
2822 | end if; | |
2823 | end Expr_Rep_Value; | |
2824 | ||
2825 | ---------------- | |
2826 | -- Expr_Value -- | |
2827 | ---------------- | |
2828 | ||
2829 | function Expr_Value (N : Node_Id) return Uint is | |
07fc65c4 GB |
2830 | Kind : constant Node_Kind := Nkind (N); |
2831 | CV_Ent : CV_Entry renames CV_Cache (Nat (N) mod CV_Cache_Size); | |
2832 | Ent : Entity_Id; | |
2833 | Val : Uint; | |
996ae0b0 RK |
2834 | |
2835 | begin | |
07fc65c4 GB |
2836 | -- If already in cache, then we know it's compile time known and |
2837 | -- we can return the value that was previously stored in the cache | |
2838 | -- since compile time known values cannot change :-) | |
2839 | ||
2840 | if CV_Ent.N = N then | |
2841 | return CV_Ent.V; | |
2842 | end if; | |
2843 | ||
2844 | -- Otherwise proceed to test value | |
2845 | ||
996ae0b0 RK |
2846 | if Is_Entity_Name (N) then |
2847 | Ent := Entity (N); | |
2848 | ||
2849 | -- An enumeration literal that was either in the source or | |
2850 | -- created as a result of static evaluation. | |
2851 | ||
2852 | if Ekind (Ent) = E_Enumeration_Literal then | |
07fc65c4 | 2853 | Val := Enumeration_Pos (Ent); |
996ae0b0 RK |
2854 | |
2855 | -- A user defined static constant | |
2856 | ||
2857 | else | |
2858 | pragma Assert (Ekind (Ent) = E_Constant); | |
07fc65c4 | 2859 | Val := Expr_Value (Constant_Value (Ent)); |
996ae0b0 RK |
2860 | end if; |
2861 | ||
2862 | -- An integer literal that was either in the source or created | |
2863 | -- as a result of static evaluation. | |
2864 | ||
2865 | elsif Kind = N_Integer_Literal then | |
07fc65c4 | 2866 | Val := Intval (N); |
996ae0b0 RK |
2867 | |
2868 | -- A real literal for a fixed-point type. This must be the fixed-point | |
2869 | -- case, either the literal is of a fixed-point type, or it is a bound | |
2870 | -- of a fixed-point type, with type universal real. In either case we | |
2871 | -- obtain the desired value from Corresponding_Integer_Value. | |
2872 | ||
2873 | elsif Kind = N_Real_Literal then | |
2874 | ||
996ae0b0 | 2875 | pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N)))); |
07fc65c4 | 2876 | Val := Corresponding_Integer_Value (N); |
996ae0b0 RK |
2877 | |
2878 | -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero | |
2879 | ||
2880 | elsif Kind = N_Attribute_Reference | |
2881 | and then Attribute_Name (N) = Name_Null_Parameter | |
2882 | then | |
07fc65c4 GB |
2883 | Val := Uint_0; |
2884 | ||
996ae0b0 RK |
2885 | -- Otherwise must be character literal |
2886 | ||
2887 | else | |
2888 | pragma Assert (Kind = N_Character_Literal); | |
2889 | Ent := Entity (N); | |
2890 | ||
2891 | -- Since Character literals of type Standard.Character don't | |
2892 | -- have any defining character literals built for them, they | |
2893 | -- do not have their Entity set, so just use their Char | |
2894 | -- code. Otherwise for user-defined character literals use | |
2895 | -- their Pos value as usual. | |
2896 | ||
2897 | if No (Ent) then | |
82c80734 | 2898 | Val := Char_Literal_Value (N); |
996ae0b0 | 2899 | else |
07fc65c4 | 2900 | Val := Enumeration_Pos (Ent); |
996ae0b0 RK |
2901 | end if; |
2902 | end if; | |
2903 | ||
07fc65c4 GB |
2904 | -- Come here with Val set to value to be returned, set cache |
2905 | ||
2906 | CV_Ent.N := N; | |
2907 | CV_Ent.V := Val; | |
2908 | return Val; | |
996ae0b0 RK |
2909 | end Expr_Value; |
2910 | ||
2911 | ------------------ | |
2912 | -- Expr_Value_E -- | |
2913 | ------------------ | |
2914 | ||
2915 | function Expr_Value_E (N : Node_Id) return Entity_Id is | |
2916 | Ent : constant Entity_Id := Entity (N); | |
2917 | ||
2918 | begin | |
2919 | if Ekind (Ent) = E_Enumeration_Literal then | |
2920 | return Ent; | |
2921 | else | |
2922 | pragma Assert (Ekind (Ent) = E_Constant); | |
2923 | return Expr_Value_E (Constant_Value (Ent)); | |
2924 | end if; | |
2925 | end Expr_Value_E; | |
2926 | ||
2927 | ------------------ | |
2928 | -- Expr_Value_R -- | |
2929 | ------------------ | |
2930 | ||
2931 | function Expr_Value_R (N : Node_Id) return Ureal is | |
2932 | Kind : constant Node_Kind := Nkind (N); | |
2933 | Ent : Entity_Id; | |
2934 | Expr : Node_Id; | |
2935 | ||
2936 | begin | |
2937 | if Kind = N_Real_Literal then | |
2938 | return Realval (N); | |
2939 | ||
2940 | elsif Kind = N_Identifier or else Kind = N_Expanded_Name then | |
2941 | Ent := Entity (N); | |
2942 | pragma Assert (Ekind (Ent) = E_Constant); | |
2943 | return Expr_Value_R (Constant_Value (Ent)); | |
2944 | ||
2945 | elsif Kind = N_Integer_Literal then | |
2946 | return UR_From_Uint (Expr_Value (N)); | |
2947 | ||
2948 | -- Strange case of VAX literals, which are at this stage transformed | |
2949 | -- into Vax_Type!x_To_y(IEEE_Literal). See Expand_N_Real_Literal in | |
2950 | -- Exp_Vfpt for further details. | |
2951 | ||
2952 | elsif Vax_Float (Etype (N)) | |
2953 | and then Nkind (N) = N_Unchecked_Type_Conversion | |
2954 | then | |
2955 | Expr := Expression (N); | |
2956 | ||
2957 | if Nkind (Expr) = N_Function_Call | |
2958 | and then Present (Parameter_Associations (Expr)) | |
2959 | then | |
2960 | Expr := First (Parameter_Associations (Expr)); | |
2961 | ||
2962 | if Nkind (Expr) = N_Real_Literal then | |
2963 | return Realval (Expr); | |
2964 | end if; | |
2965 | end if; | |
2966 | ||
2967 | -- Peculiar VMS case, if we have xxx'Null_Parameter, return 0.0 | |
2968 | ||
2969 | elsif Kind = N_Attribute_Reference | |
2970 | and then Attribute_Name (N) = Name_Null_Parameter | |
2971 | then | |
2972 | return Ureal_0; | |
2973 | end if; | |
2974 | ||
2975 | -- If we fall through, we have a node that cannot be interepreted | |
2976 | -- as a compile time constant. That is definitely an error. | |
2977 | ||
2978 | raise Program_Error; | |
2979 | end Expr_Value_R; | |
2980 | ||
2981 | ------------------ | |
2982 | -- Expr_Value_S -- | |
2983 | ------------------ | |
2984 | ||
2985 | function Expr_Value_S (N : Node_Id) return Node_Id is | |
2986 | begin | |
2987 | if Nkind (N) = N_String_Literal then | |
2988 | return N; | |
2989 | else | |
2990 | pragma Assert (Ekind (Entity (N)) = E_Constant); | |
2991 | return Expr_Value_S (Constant_Value (Entity (N))); | |
2992 | end if; | |
2993 | end Expr_Value_S; | |
2994 | ||
fbf5a39b AC |
2995 | -------------------------- |
2996 | -- Flag_Non_Static_Expr -- | |
2997 | -------------------------- | |
2998 | ||
2999 | procedure Flag_Non_Static_Expr (Msg : String; Expr : Node_Id) is | |
3000 | begin | |
3001 | if Error_Posted (Expr) and then not All_Errors_Mode then | |
3002 | return; | |
3003 | else | |
3004 | Error_Msg_F (Msg, Expr); | |
3005 | Why_Not_Static (Expr); | |
3006 | end if; | |
3007 | end Flag_Non_Static_Expr; | |
3008 | ||
996ae0b0 RK |
3009 | -------------- |
3010 | -- Fold_Str -- | |
3011 | -------------- | |
3012 | ||
fbf5a39b | 3013 | procedure Fold_Str (N : Node_Id; Val : String_Id; Static : Boolean) is |
996ae0b0 RK |
3014 | Loc : constant Source_Ptr := Sloc (N); |
3015 | Typ : constant Entity_Id := Etype (N); | |
3016 | ||
3017 | begin | |
3018 | Rewrite (N, Make_String_Literal (Loc, Strval => Val)); | |
fbf5a39b AC |
3019 | |
3020 | -- We now have the literal with the right value, both the actual type | |
3021 | -- and the expected type of this literal are taken from the expression | |
3022 | -- that was evaluated. | |
3023 | ||
3024 | Analyze (N); | |
3025 | Set_Is_Static_Expression (N, Static); | |
3026 | Set_Etype (N, Typ); | |
3027 | Resolve (N); | |
996ae0b0 RK |
3028 | end Fold_Str; |
3029 | ||
3030 | --------------- | |
3031 | -- Fold_Uint -- | |
3032 | --------------- | |
3033 | ||
fbf5a39b | 3034 | procedure Fold_Uint (N : Node_Id; Val : Uint; Static : Boolean) is |
996ae0b0 | 3035 | Loc : constant Source_Ptr := Sloc (N); |
fbf5a39b AC |
3036 | Typ : Entity_Id := Etype (N); |
3037 | Ent : Entity_Id; | |
996ae0b0 RK |
3038 | |
3039 | begin | |
fbf5a39b AC |
3040 | -- If we are folding a named number, retain the entity in the |
3041 | -- literal, for ASIS use. | |
3042 | ||
3043 | if Is_Entity_Name (N) | |
3044 | and then Ekind (Entity (N)) = E_Named_Integer | |
3045 | then | |
3046 | Ent := Entity (N); | |
3047 | else | |
3048 | Ent := Empty; | |
3049 | end if; | |
3050 | ||
3051 | if Is_Private_Type (Typ) then | |
3052 | Typ := Full_View (Typ); | |
3053 | end if; | |
3054 | ||
996ae0b0 RK |
3055 | -- For a result of type integer, subsitute an N_Integer_Literal node |
3056 | -- for the result of the compile time evaluation of the expression. | |
3057 | ||
fbf5a39b | 3058 | if Is_Integer_Type (Typ) then |
996ae0b0 | 3059 | Rewrite (N, Make_Integer_Literal (Loc, Val)); |
fbf5a39b | 3060 | Set_Original_Entity (N, Ent); |
996ae0b0 RK |
3061 | |
3062 | -- Otherwise we have an enumeration type, and we substitute either | |
3063 | -- an N_Identifier or N_Character_Literal to represent the enumeration | |
3064 | -- literal corresponding to the given value, which must always be in | |
3065 | -- range, because appropriate tests have already been made for this. | |
3066 | ||
fbf5a39b | 3067 | else pragma Assert (Is_Enumeration_Type (Typ)); |
996ae0b0 RK |
3068 | Rewrite (N, Get_Enum_Lit_From_Pos (Etype (N), Val, Loc)); |
3069 | end if; | |
3070 | ||
3071 | -- We now have the literal with the right value, both the actual type | |
3072 | -- and the expected type of this literal are taken from the expression | |
3073 | -- that was evaluated. | |
3074 | ||
3075 | Analyze (N); | |
fbf5a39b | 3076 | Set_Is_Static_Expression (N, Static); |
996ae0b0 | 3077 | Set_Etype (N, Typ); |
fbf5a39b | 3078 | Resolve (N); |
996ae0b0 RK |
3079 | end Fold_Uint; |
3080 | ||
3081 | ---------------- | |
3082 | -- Fold_Ureal -- | |
3083 | ---------------- | |
3084 | ||
fbf5a39b | 3085 | procedure Fold_Ureal (N : Node_Id; Val : Ureal; Static : Boolean) is |
996ae0b0 RK |
3086 | Loc : constant Source_Ptr := Sloc (N); |
3087 | Typ : constant Entity_Id := Etype (N); | |
fbf5a39b | 3088 | Ent : Entity_Id; |
996ae0b0 RK |
3089 | |
3090 | begin | |
fbf5a39b AC |
3091 | -- If we are folding a named number, retain the entity in the |
3092 | -- literal, for ASIS use. | |
3093 | ||
3094 | if Is_Entity_Name (N) | |
3095 | and then Ekind (Entity (N)) = E_Named_Real | |
3096 | then | |
3097 | Ent := Entity (N); | |
3098 | else | |
3099 | Ent := Empty; | |
3100 | end if; | |
3101 | ||
996ae0b0 | 3102 | Rewrite (N, Make_Real_Literal (Loc, Realval => Val)); |
fbf5a39b | 3103 | Set_Original_Entity (N, Ent); |
996ae0b0 RK |
3104 | |
3105 | -- Both the actual and expected type comes from the original expression | |
3106 | ||
fbf5a39b AC |
3107 | Analyze (N); |
3108 | Set_Is_Static_Expression (N, Static); | |
996ae0b0 | 3109 | Set_Etype (N, Typ); |
fbf5a39b | 3110 | Resolve (N); |
996ae0b0 RK |
3111 | end Fold_Ureal; |
3112 | ||
3113 | --------------- | |
3114 | -- From_Bits -- | |
3115 | --------------- | |
3116 | ||
3117 | function From_Bits (B : Bits; T : Entity_Id) return Uint is | |
3118 | V : Uint := Uint_0; | |
3119 | ||
3120 | begin | |
3121 | for J in 0 .. B'Last loop | |
3122 | if B (J) then | |
3123 | V := V + 2 ** J; | |
3124 | end if; | |
3125 | end loop; | |
3126 | ||
3127 | if Non_Binary_Modulus (T) then | |
3128 | V := V mod Modulus (T); | |
3129 | end if; | |
3130 | ||
3131 | return V; | |
3132 | end From_Bits; | |
3133 | ||
3134 | -------------------- | |
3135 | -- Get_String_Val -- | |
3136 | -------------------- | |
3137 | ||
3138 | function Get_String_Val (N : Node_Id) return Node_Id is | |
3139 | begin | |
3140 | if Nkind (N) = N_String_Literal then | |
3141 | return N; | |
3142 | ||
3143 | elsif Nkind (N) = N_Character_Literal then | |
3144 | return N; | |
3145 | ||
3146 | else | |
3147 | pragma Assert (Is_Entity_Name (N)); | |
3148 | return Get_String_Val (Constant_Value (Entity (N))); | |
3149 | end if; | |
3150 | end Get_String_Val; | |
3151 | ||
fbf5a39b AC |
3152 | ---------------- |
3153 | -- Initialize -- | |
3154 | ---------------- | |
3155 | ||
3156 | procedure Initialize is | |
3157 | begin | |
3158 | CV_Cache := (others => (Node_High_Bound, Uint_0)); | |
3159 | end Initialize; | |
3160 | ||
996ae0b0 RK |
3161 | -------------------- |
3162 | -- In_Subrange_Of -- | |
3163 | -------------------- | |
3164 | ||
3165 | function In_Subrange_Of | |
3166 | (T1 : Entity_Id; | |
3167 | T2 : Entity_Id; | |
f44fe430 | 3168 | Fixed_Int : Boolean := False) return Boolean |
996ae0b0 RK |
3169 | is |
3170 | L1 : Node_Id; | |
3171 | H1 : Node_Id; | |
3172 | ||
3173 | L2 : Node_Id; | |
3174 | H2 : Node_Id; | |
3175 | ||
3176 | begin | |
3177 | if T1 = T2 or else Is_Subtype_Of (T1, T2) then | |
3178 | return True; | |
3179 | ||
3180 | -- Never in range if both types are not scalar. Don't know if this can | |
3181 | -- actually happen, but just in case. | |
3182 | ||
3183 | elsif not Is_Scalar_Type (T1) or else not Is_Scalar_Type (T1) then | |
3184 | return False; | |
3185 | ||
3186 | else | |
3187 | L1 := Type_Low_Bound (T1); | |
3188 | H1 := Type_High_Bound (T1); | |
3189 | ||
3190 | L2 := Type_Low_Bound (T2); | |
3191 | H2 := Type_High_Bound (T2); | |
3192 | ||
3193 | -- Check bounds to see if comparison possible at compile time | |
3194 | ||
3195 | if Compile_Time_Compare (L1, L2) in Compare_GE | |
3196 | and then | |
3197 | Compile_Time_Compare (H1, H2) in Compare_LE | |
3198 | then | |
3199 | return True; | |
3200 | end if; | |
3201 | ||
3202 | -- If bounds not comparable at compile time, then the bounds of T2 | |
3203 | -- must be compile time known or we cannot answer the query. | |
3204 | ||
3205 | if not Compile_Time_Known_Value (L2) | |
3206 | or else not Compile_Time_Known_Value (H2) | |
3207 | then | |
3208 | return False; | |
3209 | end if; | |
3210 | ||
3211 | -- If the bounds of T1 are know at compile time then use these | |
3212 | -- ones, otherwise use the bounds of the base type (which are of | |
3213 | -- course always static). | |
3214 | ||
3215 | if not Compile_Time_Known_Value (L1) then | |
3216 | L1 := Type_Low_Bound (Base_Type (T1)); | |
3217 | end if; | |
3218 | ||
3219 | if not Compile_Time_Known_Value (H1) then | |
3220 | H1 := Type_High_Bound (Base_Type (T1)); | |
3221 | end if; | |
3222 | ||
3223 | -- Fixed point types should be considered as such only if | |
3224 | -- flag Fixed_Int is set to False. | |
3225 | ||
3226 | if Is_Floating_Point_Type (T1) or else Is_Floating_Point_Type (T2) | |
3227 | or else (Is_Fixed_Point_Type (T1) and then not Fixed_Int) | |
3228 | or else (Is_Fixed_Point_Type (T2) and then not Fixed_Int) | |
3229 | then | |
3230 | return | |
3231 | Expr_Value_R (L2) <= Expr_Value_R (L1) | |
3232 | and then | |
3233 | Expr_Value_R (H2) >= Expr_Value_R (H1); | |
3234 | ||
3235 | else | |
3236 | return | |
3237 | Expr_Value (L2) <= Expr_Value (L1) | |
3238 | and then | |
3239 | Expr_Value (H2) >= Expr_Value (H1); | |
3240 | ||
3241 | end if; | |
3242 | end if; | |
3243 | ||
3244 | -- If any exception occurs, it means that we have some bug in the compiler | |
3245 | -- possibly triggered by a previous error, or by some unforseen peculiar | |
3246 | -- occurrence. However, this is only an optimization attempt, so there is | |
3247 | -- really no point in crashing the compiler. Instead we just decide, too | |
3248 | -- bad, we can't figure out the answer in this case after all. | |
3249 | ||
3250 | exception | |
3251 | when others => | |
3252 | ||
3253 | -- Debug flag K disables this behavior (useful for debugging) | |
3254 | ||
3255 | if Debug_Flag_K then | |
3256 | raise; | |
3257 | else | |
3258 | return False; | |
3259 | end if; | |
3260 | end In_Subrange_Of; | |
3261 | ||
3262 | ----------------- | |
3263 | -- Is_In_Range -- | |
3264 | ----------------- | |
3265 | ||
3266 | function Is_In_Range | |
3267 | (N : Node_Id; | |
3268 | Typ : Entity_Id; | |
3269 | Fixed_Int : Boolean := False; | |
f44fe430 | 3270 | Int_Real : Boolean := False) return Boolean |
996ae0b0 RK |
3271 | is |
3272 | Val : Uint; | |
3273 | Valr : Ureal; | |
3274 | ||
3275 | begin | |
82c80734 | 3276 | -- Universal types have no range limits, so always in range |
996ae0b0 RK |
3277 | |
3278 | if Typ = Universal_Integer or else Typ = Universal_Real then | |
3279 | return True; | |
3280 | ||
3281 | -- Never in range if not scalar type. Don't know if this can | |
3282 | -- actually happen, but our spec allows it, so we must check! | |
3283 | ||
3284 | elsif not Is_Scalar_Type (Typ) then | |
3285 | return False; | |
3286 | ||
82c80734 | 3287 | -- Never in range unless we have a compile time known value |
996ae0b0 RK |
3288 | |
3289 | elsif not Compile_Time_Known_Value (N) then | |
3290 | return False; | |
3291 | ||
3292 | else | |
3293 | declare | |
3294 | Lo : constant Node_Id := Type_Low_Bound (Typ); | |
3295 | Hi : constant Node_Id := Type_High_Bound (Typ); | |
3296 | LB_Known : constant Boolean := Compile_Time_Known_Value (Lo); | |
3297 | UB_Known : constant Boolean := Compile_Time_Known_Value (Hi); | |
3298 | ||
3299 | begin | |
3300 | -- Fixed point types should be considered as such only in | |
3301 | -- flag Fixed_Int is set to False. | |
3302 | ||
3303 | if Is_Floating_Point_Type (Typ) | |
3304 | or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int) | |
3305 | or else Int_Real | |
3306 | then | |
3307 | Valr := Expr_Value_R (N); | |
3308 | ||
3309 | if LB_Known and then Valr >= Expr_Value_R (Lo) | |
3310 | and then UB_Known and then Valr <= Expr_Value_R (Hi) | |
3311 | then | |
3312 | return True; | |
3313 | else | |
3314 | return False; | |
3315 | end if; | |
3316 | ||
3317 | else | |
3318 | Val := Expr_Value (N); | |
3319 | ||
3320 | if LB_Known and then Val >= Expr_Value (Lo) | |
3321 | and then UB_Known and then Val <= Expr_Value (Hi) | |
3322 | then | |
3323 | return True; | |
3324 | else | |
3325 | return False; | |
3326 | end if; | |
3327 | end if; | |
3328 | end; | |
3329 | end if; | |
3330 | end Is_In_Range; | |
3331 | ||
3332 | ------------------- | |
3333 | -- Is_Null_Range -- | |
3334 | ------------------- | |
3335 | ||
3336 | function Is_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is | |
3337 | Typ : constant Entity_Id := Etype (Lo); | |
3338 | ||
3339 | begin | |
3340 | if not Compile_Time_Known_Value (Lo) | |
3341 | or else not Compile_Time_Known_Value (Hi) | |
3342 | then | |
3343 | return False; | |
3344 | end if; | |
3345 | ||
3346 | if Is_Discrete_Type (Typ) then | |
3347 | return Expr_Value (Lo) > Expr_Value (Hi); | |
3348 | ||
3349 | else | |
3350 | pragma Assert (Is_Real_Type (Typ)); | |
3351 | return Expr_Value_R (Lo) > Expr_Value_R (Hi); | |
3352 | end if; | |
3353 | end Is_Null_Range; | |
3354 | ||
3355 | ----------------------------- | |
3356 | -- Is_OK_Static_Expression -- | |
3357 | ----------------------------- | |
3358 | ||
3359 | function Is_OK_Static_Expression (N : Node_Id) return Boolean is | |
3360 | begin | |
3361 | return Is_Static_Expression (N) | |
3362 | and then not Raises_Constraint_Error (N); | |
3363 | end Is_OK_Static_Expression; | |
3364 | ||
3365 | ------------------------ | |
3366 | -- Is_OK_Static_Range -- | |
3367 | ------------------------ | |
3368 | ||
3369 | -- A static range is a range whose bounds are static expressions, or a | |
3370 | -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)). | |
3371 | -- We have already converted range attribute references, so we get the | |
3372 | -- "or" part of this rule without needing a special test. | |
3373 | ||
3374 | function Is_OK_Static_Range (N : Node_Id) return Boolean is | |
3375 | begin | |
3376 | return Is_OK_Static_Expression (Low_Bound (N)) | |
3377 | and then Is_OK_Static_Expression (High_Bound (N)); | |
3378 | end Is_OK_Static_Range; | |
3379 | ||
3380 | -------------------------- | |
3381 | -- Is_OK_Static_Subtype -- | |
3382 | -------------------------- | |
3383 | ||
3384 | -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) | |
3385 | -- where neither bound raises constraint error when evaluated. | |
3386 | ||
3387 | function Is_OK_Static_Subtype (Typ : Entity_Id) return Boolean is | |
3388 | Base_T : constant Entity_Id := Base_Type (Typ); | |
3389 | Anc_Subt : Entity_Id; | |
3390 | ||
3391 | begin | |
3392 | -- First a quick check on the non static subtype flag. As described | |
3393 | -- in further detail in Einfo, this flag is not decisive in all cases, | |
3394 | -- but if it is set, then the subtype is definitely non-static. | |
3395 | ||
3396 | if Is_Non_Static_Subtype (Typ) then | |
3397 | return False; | |
3398 | end if; | |
3399 | ||
3400 | Anc_Subt := Ancestor_Subtype (Typ); | |
3401 | ||
3402 | if Anc_Subt = Empty then | |
3403 | Anc_Subt := Base_T; | |
3404 | end if; | |
3405 | ||
3406 | if Is_Generic_Type (Root_Type (Base_T)) | |
3407 | or else Is_Generic_Actual_Type (Base_T) | |
3408 | then | |
3409 | return False; | |
3410 | ||
3411 | -- String types | |
3412 | ||
3413 | elsif Is_String_Type (Typ) then | |
3414 | return | |
3415 | Ekind (Typ) = E_String_Literal_Subtype | |
3416 | or else | |
3417 | (Is_OK_Static_Subtype (Component_Type (Typ)) | |
3418 | and then Is_OK_Static_Subtype (Etype (First_Index (Typ)))); | |
3419 | ||
3420 | -- Scalar types | |
3421 | ||
3422 | elsif Is_Scalar_Type (Typ) then | |
3423 | if Base_T = Typ then | |
3424 | return True; | |
3425 | ||
3426 | else | |
3427 | -- Scalar_Range (Typ) might be an N_Subtype_Indication, so | |
3428 | -- use Get_Type_Low,High_Bound. | |
3429 | ||
3430 | return Is_OK_Static_Subtype (Anc_Subt) | |
3431 | and then Is_OK_Static_Expression (Type_Low_Bound (Typ)) | |
3432 | and then Is_OK_Static_Expression (Type_High_Bound (Typ)); | |
3433 | end if; | |
3434 | ||
3435 | -- Types other than string and scalar types are never static | |
3436 | ||
3437 | else | |
3438 | return False; | |
3439 | end if; | |
3440 | end Is_OK_Static_Subtype; | |
3441 | ||
3442 | --------------------- | |
3443 | -- Is_Out_Of_Range -- | |
3444 | --------------------- | |
3445 | ||
3446 | function Is_Out_Of_Range | |
3447 | (N : Node_Id; | |
3448 | Typ : Entity_Id; | |
3449 | Fixed_Int : Boolean := False; | |
f44fe430 | 3450 | Int_Real : Boolean := False) return Boolean |
996ae0b0 RK |
3451 | is |
3452 | Val : Uint; | |
3453 | Valr : Ureal; | |
3454 | ||
3455 | begin | |
82c80734 | 3456 | -- Universal types have no range limits, so always in range |
996ae0b0 RK |
3457 | |
3458 | if Typ = Universal_Integer or else Typ = Universal_Real then | |
3459 | return False; | |
3460 | ||
3461 | -- Never out of range if not scalar type. Don't know if this can | |
3462 | -- actually happen, but our spec allows it, so we must check! | |
3463 | ||
3464 | elsif not Is_Scalar_Type (Typ) then | |
3465 | return False; | |
3466 | ||
3467 | -- Never out of range if this is a generic type, since the bounds | |
3468 | -- of generic types are junk. Note that if we only checked for | |
3469 | -- static expressions (instead of compile time known values) below, | |
3470 | -- we would not need this check, because values of a generic type | |
3471 | -- can never be static, but they can be known at compile time. | |
3472 | ||
3473 | elsif Is_Generic_Type (Typ) then | |
3474 | return False; | |
3475 | ||
fbf5a39b | 3476 | -- Never out of range unless we have a compile time known value |
996ae0b0 RK |
3477 | |
3478 | elsif not Compile_Time_Known_Value (N) then | |
3479 | return False; | |
3480 | ||
3481 | else | |
3482 | declare | |
3483 | Lo : constant Node_Id := Type_Low_Bound (Typ); | |
3484 | Hi : constant Node_Id := Type_High_Bound (Typ); | |
3485 | LB_Known : constant Boolean := Compile_Time_Known_Value (Lo); | |
3486 | UB_Known : constant Boolean := Compile_Time_Known_Value (Hi); | |
3487 | ||
3488 | begin | |
3489 | -- Real types (note that fixed-point types are not treated | |
3490 | -- as being of a real type if the flag Fixed_Int is set, | |
3491 | -- since in that case they are regarded as integer types). | |
3492 | ||
3493 | if Is_Floating_Point_Type (Typ) | |
3494 | or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int) | |
3495 | or else Int_Real | |
3496 | then | |
3497 | Valr := Expr_Value_R (N); | |
3498 | ||
3499 | if LB_Known and then Valr < Expr_Value_R (Lo) then | |
3500 | return True; | |
3501 | ||
3502 | elsif UB_Known and then Expr_Value_R (Hi) < Valr then | |
3503 | return True; | |
3504 | ||
3505 | else | |
3506 | return False; | |
3507 | end if; | |
3508 | ||
3509 | else | |
3510 | Val := Expr_Value (N); | |
3511 | ||
3512 | if LB_Known and then Val < Expr_Value (Lo) then | |
3513 | return True; | |
3514 | ||
3515 | elsif UB_Known and then Expr_Value (Hi) < Val then | |
3516 | return True; | |
3517 | ||
3518 | else | |
3519 | return False; | |
3520 | end if; | |
3521 | end if; | |
3522 | end; | |
3523 | end if; | |
3524 | end Is_Out_Of_Range; | |
3525 | ||
3526 | --------------------- | |
3527 | -- Is_Static_Range -- | |
3528 | --------------------- | |
3529 | ||
3530 | -- A static range is a range whose bounds are static expressions, or a | |
3531 | -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)). | |
3532 | -- We have already converted range attribute references, so we get the | |
3533 | -- "or" part of this rule without needing a special test. | |
3534 | ||
3535 | function Is_Static_Range (N : Node_Id) return Boolean is | |
3536 | begin | |
3537 | return Is_Static_Expression (Low_Bound (N)) | |
3538 | and then Is_Static_Expression (High_Bound (N)); | |
3539 | end Is_Static_Range; | |
3540 | ||
3541 | ----------------------- | |
3542 | -- Is_Static_Subtype -- | |
3543 | ----------------------- | |
3544 | ||
82c80734 | 3545 | -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) |
996ae0b0 RK |
3546 | |
3547 | function Is_Static_Subtype (Typ : Entity_Id) return Boolean is | |
3548 | Base_T : constant Entity_Id := Base_Type (Typ); | |
3549 | Anc_Subt : Entity_Id; | |
3550 | ||
3551 | begin | |
3552 | -- First a quick check on the non static subtype flag. As described | |
3553 | -- in further detail in Einfo, this flag is not decisive in all cases, | |
3554 | -- but if it is set, then the subtype is definitely non-static. | |
3555 | ||
3556 | if Is_Non_Static_Subtype (Typ) then | |
3557 | return False; | |
3558 | end if; | |
3559 | ||
3560 | Anc_Subt := Ancestor_Subtype (Typ); | |
3561 | ||
3562 | if Anc_Subt = Empty then | |
3563 | Anc_Subt := Base_T; | |
3564 | end if; | |
3565 | ||
3566 | if Is_Generic_Type (Root_Type (Base_T)) | |
3567 | or else Is_Generic_Actual_Type (Base_T) | |
3568 | then | |
3569 | return False; | |
3570 | ||
3571 | -- String types | |
3572 | ||
3573 | elsif Is_String_Type (Typ) then | |
3574 | return | |
3575 | Ekind (Typ) = E_String_Literal_Subtype | |
3576 | or else | |
3577 | (Is_Static_Subtype (Component_Type (Typ)) | |
3578 | and then Is_Static_Subtype (Etype (First_Index (Typ)))); | |
3579 | ||
3580 | -- Scalar types | |
3581 | ||
3582 | elsif Is_Scalar_Type (Typ) then | |
3583 | if Base_T = Typ then | |
3584 | return True; | |
3585 | ||
3586 | else | |
3587 | return Is_Static_Subtype (Anc_Subt) | |
3588 | and then Is_Static_Expression (Type_Low_Bound (Typ)) | |
3589 | and then Is_Static_Expression (Type_High_Bound (Typ)); | |
3590 | end if; | |
3591 | ||
3592 | -- Types other than string and scalar types are never static | |
3593 | ||
3594 | else | |
3595 | return False; | |
3596 | end if; | |
3597 | end Is_Static_Subtype; | |
3598 | ||
3599 | -------------------- | |
3600 | -- Not_Null_Range -- | |
3601 | -------------------- | |
3602 | ||
3603 | function Not_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is | |
3604 | Typ : constant Entity_Id := Etype (Lo); | |
3605 | ||
3606 | begin | |
3607 | if not Compile_Time_Known_Value (Lo) | |
3608 | or else not Compile_Time_Known_Value (Hi) | |
3609 | then | |
3610 | return False; | |
3611 | end if; | |
3612 | ||
3613 | if Is_Discrete_Type (Typ) then | |
3614 | return Expr_Value (Lo) <= Expr_Value (Hi); | |
3615 | ||
3616 | else | |
3617 | pragma Assert (Is_Real_Type (Typ)); | |
3618 | ||
3619 | return Expr_Value_R (Lo) <= Expr_Value_R (Hi); | |
3620 | end if; | |
3621 | end Not_Null_Range; | |
3622 | ||
3623 | ------------- | |
3624 | -- OK_Bits -- | |
3625 | ------------- | |
3626 | ||
3627 | function OK_Bits (N : Node_Id; Bits : Uint) return Boolean is | |
3628 | begin | |
3629 | -- We allow a maximum of 500,000 bits which seems a reasonable limit | |
3630 | ||
3631 | if Bits < 500_000 then | |
3632 | return True; | |
3633 | ||
3634 | else | |
3635 | Error_Msg_N ("static value too large, capacity exceeded", N); | |
3636 | return False; | |
3637 | end if; | |
3638 | end OK_Bits; | |
3639 | ||
3640 | ------------------ | |
3641 | -- Out_Of_Range -- | |
3642 | ------------------ | |
3643 | ||
3644 | procedure Out_Of_Range (N : Node_Id) is | |
3645 | begin | |
3646 | -- If we have the static expression case, then this is an illegality | |
3647 | -- in Ada 95 mode, except that in an instance, we never generate an | |
3648 | -- error (if the error is legitimate, it was already diagnosed in | |
3649 | -- the template). The expression to compute the length of a packed | |
3650 | -- array is attached to the array type itself, and deserves a separate | |
3651 | -- message. | |
3652 | ||
3653 | if Is_Static_Expression (N) | |
3654 | and then not In_Instance | |
fbf5a39b | 3655 | and then not In_Inlined_Body |
0ab80019 | 3656 | and then Ada_Version >= Ada_95 |
996ae0b0 | 3657 | then |
996ae0b0 RK |
3658 | if Nkind (Parent (N)) = N_Defining_Identifier |
3659 | and then Is_Array_Type (Parent (N)) | |
3660 | and then Present (Packed_Array_Type (Parent (N))) | |
3661 | and then Present (First_Rep_Item (Parent (N))) | |
3662 | then | |
3663 | Error_Msg_N | |
3664 | ("length of packed array must not exceed Integer''Last", | |
3665 | First_Rep_Item (Parent (N))); | |
3666 | Rewrite (N, Make_Integer_Literal (Sloc (N), Uint_1)); | |
3667 | ||
3668 | else | |
3669 | Apply_Compile_Time_Constraint_Error | |
07fc65c4 | 3670 | (N, "value not in range of}", CE_Range_Check_Failed); |
996ae0b0 RK |
3671 | end if; |
3672 | ||
3673 | -- Here we generate a warning for the Ada 83 case, or when we are | |
3674 | -- in an instance, or when we have a non-static expression case. | |
3675 | ||
3676 | else | |
996ae0b0 | 3677 | Apply_Compile_Time_Constraint_Error |
07fc65c4 | 3678 | (N, "value not in range of}?", CE_Range_Check_Failed); |
996ae0b0 RK |
3679 | end if; |
3680 | end Out_Of_Range; | |
3681 | ||
3682 | ------------------------- | |
3683 | -- Rewrite_In_Raise_CE -- | |
3684 | ------------------------- | |
3685 | ||
3686 | procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id) is | |
3687 | Typ : constant Entity_Id := Etype (N); | |
3688 | ||
3689 | begin | |
3690 | -- If we want to raise CE in the condition of a raise_CE node | |
3691 | -- we may as well get rid of the condition | |
3692 | ||
3693 | if Present (Parent (N)) | |
3694 | and then Nkind (Parent (N)) = N_Raise_Constraint_Error | |
3695 | then | |
3696 | Set_Condition (Parent (N), Empty); | |
3697 | ||
3698 | -- If the expression raising CE is a N_Raise_CE node, we can use | |
3699 | -- that one. We just preserve the type of the context | |
3700 | ||
3701 | elsif Nkind (Exp) = N_Raise_Constraint_Error then | |
3702 | Rewrite (N, Exp); | |
3703 | Set_Etype (N, Typ); | |
3704 | ||
3705 | -- We have to build an explicit raise_ce node | |
3706 | ||
3707 | else | |
07fc65c4 GB |
3708 | Rewrite (N, |
3709 | Make_Raise_Constraint_Error (Sloc (Exp), | |
3710 | Reason => CE_Range_Check_Failed)); | |
996ae0b0 RK |
3711 | Set_Raises_Constraint_Error (N); |
3712 | Set_Etype (N, Typ); | |
3713 | end if; | |
3714 | end Rewrite_In_Raise_CE; | |
3715 | ||
3716 | --------------------- | |
3717 | -- String_Type_Len -- | |
3718 | --------------------- | |
3719 | ||
3720 | function String_Type_Len (Stype : Entity_Id) return Uint is | |
3721 | NT : constant Entity_Id := Etype (First_Index (Stype)); | |
3722 | T : Entity_Id; | |
3723 | ||
3724 | begin | |
3725 | if Is_OK_Static_Subtype (NT) then | |
3726 | T := NT; | |
3727 | else | |
3728 | T := Base_Type (NT); | |
3729 | end if; | |
3730 | ||
3731 | return Expr_Value (Type_High_Bound (T)) - | |
3732 | Expr_Value (Type_Low_Bound (T)) + 1; | |
3733 | end String_Type_Len; | |
3734 | ||
3735 | ------------------------------------ | |
3736 | -- Subtypes_Statically_Compatible -- | |
3737 | ------------------------------------ | |
3738 | ||
3739 | function Subtypes_Statically_Compatible | |
f44fe430 RD |
3740 | (T1 : Entity_Id; |
3741 | T2 : Entity_Id) return Boolean | |
996ae0b0 RK |
3742 | is |
3743 | begin | |
3744 | if Is_Scalar_Type (T1) then | |
3745 | ||
3746 | -- Definitely compatible if we match | |
3747 | ||
3748 | if Subtypes_Statically_Match (T1, T2) then | |
3749 | return True; | |
3750 | ||
3751 | -- If either subtype is nonstatic then they're not compatible | |
3752 | ||
3753 | elsif not Is_Static_Subtype (T1) | |
3754 | or else not Is_Static_Subtype (T2) | |
3755 | then | |
3756 | return False; | |
3757 | ||
3758 | -- If either type has constraint error bounds, then consider that | |
3759 | -- they match to avoid junk cascaded errors here. | |
3760 | ||
3761 | elsif not Is_OK_Static_Subtype (T1) | |
3762 | or else not Is_OK_Static_Subtype (T2) | |
3763 | then | |
3764 | return True; | |
3765 | ||
3766 | -- Base types must match, but we don't check that (should | |
3767 | -- we???) but we do at least check that both types are | |
3768 | -- real, or both types are not real. | |
3769 | ||
fbf5a39b | 3770 | elsif Is_Real_Type (T1) /= Is_Real_Type (T2) then |
996ae0b0 RK |
3771 | return False; |
3772 | ||
3773 | -- Here we check the bounds | |
3774 | ||
3775 | else | |
3776 | declare | |
3777 | LB1 : constant Node_Id := Type_Low_Bound (T1); | |
3778 | HB1 : constant Node_Id := Type_High_Bound (T1); | |
3779 | LB2 : constant Node_Id := Type_Low_Bound (T2); | |
3780 | HB2 : constant Node_Id := Type_High_Bound (T2); | |
3781 | ||
3782 | begin | |
3783 | if Is_Real_Type (T1) then | |
3784 | return | |
3785 | (Expr_Value_R (LB1) > Expr_Value_R (HB1)) | |
3786 | or else | |
3787 | (Expr_Value_R (LB2) <= Expr_Value_R (LB1) | |
3788 | and then | |
3789 | Expr_Value_R (HB1) <= Expr_Value_R (HB2)); | |
3790 | ||
3791 | else | |
3792 | return | |
3793 | (Expr_Value (LB1) > Expr_Value (HB1)) | |
3794 | or else | |
3795 | (Expr_Value (LB2) <= Expr_Value (LB1) | |
3796 | and then | |
3797 | Expr_Value (HB1) <= Expr_Value (HB2)); | |
3798 | end if; | |
3799 | end; | |
3800 | end if; | |
3801 | ||
3802 | elsif Is_Access_Type (T1) then | |
3803 | return not Is_Constrained (T2) | |
3804 | or else Subtypes_Statically_Match | |
3805 | (Designated_Type (T1), Designated_Type (T2)); | |
3806 | ||
3807 | else | |
3808 | return (Is_Composite_Type (T1) and then not Is_Constrained (T2)) | |
3809 | or else Subtypes_Statically_Match (T1, T2); | |
3810 | end if; | |
3811 | end Subtypes_Statically_Compatible; | |
3812 | ||
3813 | ------------------------------- | |
3814 | -- Subtypes_Statically_Match -- | |
3815 | ------------------------------- | |
3816 | ||
3817 | -- Subtypes statically match if they have statically matching constraints | |
3818 | -- (RM 4.9.1(2)). Constraints statically match if there are none, or if | |
3819 | -- they are the same identical constraint, or if they are static and the | |
3820 | -- values match (RM 4.9.1(1)). | |
3821 | ||
3822 | function Subtypes_Statically_Match (T1, T2 : Entity_Id) return Boolean is | |
3823 | begin | |
3824 | -- A type always statically matches itself | |
3825 | ||
3826 | if T1 = T2 then | |
3827 | return True; | |
3828 | ||
3829 | -- Scalar types | |
3830 | ||
3831 | elsif Is_Scalar_Type (T1) then | |
3832 | ||
3833 | -- Base types must be the same | |
3834 | ||
3835 | if Base_Type (T1) /= Base_Type (T2) then | |
3836 | return False; | |
3837 | end if; | |
3838 | ||
3839 | -- A constrained numeric subtype never matches an unconstrained | |
3840 | -- subtype, i.e. both types must be constrained or unconstrained. | |
3841 | ||
3842 | -- To understand the requirement for this test, see RM 4.9.1(1). | |
3843 | -- As is made clear in RM 3.5.4(11), type Integer, for example | |
3844 | -- is a constrained subtype with constraint bounds matching the | |
3845 | -- bounds of its corresponding uncontrained base type. In this | |
3846 | -- situation, Integer and Integer'Base do not statically match, | |
3847 | -- even though they have the same bounds. | |
3848 | ||
3849 | -- We only apply this test to types in Standard and types that | |
3850 | -- appear in user programs. That way, we do not have to be | |
3851 | -- too careful about setting Is_Constrained right for itypes. | |
3852 | ||
3853 | if Is_Numeric_Type (T1) | |
3854 | and then (Is_Constrained (T1) /= Is_Constrained (T2)) | |
3855 | and then (Scope (T1) = Standard_Standard | |
3856 | or else Comes_From_Source (T1)) | |
3857 | and then (Scope (T2) = Standard_Standard | |
3858 | or else Comes_From_Source (T2)) | |
3859 | then | |
3860 | return False; | |
82c80734 RD |
3861 | |
3862 | -- A generic scalar type does not statically match its base | |
3863 | -- type (AI-311). In this case we make sure that the formals, | |
3864 | -- which are first subtypes of their bases, are constrained. | |
3865 | ||
3866 | elsif Is_Generic_Type (T1) | |
3867 | and then Is_Generic_Type (T2) | |
3868 | and then (Is_Constrained (T1) /= Is_Constrained (T2)) | |
3869 | then | |
3870 | return False; | |
996ae0b0 RK |
3871 | end if; |
3872 | ||
3873 | -- If there was an error in either range, then just assume | |
3874 | -- the types statically match to avoid further junk errors | |
3875 | ||
3876 | if Error_Posted (Scalar_Range (T1)) | |
3877 | or else | |
3878 | Error_Posted (Scalar_Range (T2)) | |
3879 | then | |
3880 | return True; | |
3881 | end if; | |
3882 | ||
3883 | -- Otherwise both types have bound that can be compared | |
3884 | ||
3885 | declare | |
3886 | LB1 : constant Node_Id := Type_Low_Bound (T1); | |
3887 | HB1 : constant Node_Id := Type_High_Bound (T1); | |
3888 | LB2 : constant Node_Id := Type_Low_Bound (T2); | |
3889 | HB2 : constant Node_Id := Type_High_Bound (T2); | |
3890 | ||
3891 | begin | |
3892 | -- If the bounds are the same tree node, then match | |
3893 | ||
3894 | if LB1 = LB2 and then HB1 = HB2 then | |
3895 | return True; | |
3896 | ||
3897 | -- Otherwise bounds must be static and identical value | |
3898 | ||
3899 | else | |
3900 | if not Is_Static_Subtype (T1) | |
3901 | or else not Is_Static_Subtype (T2) | |
3902 | then | |
3903 | return False; | |
3904 | ||
3905 | -- If either type has constraint error bounds, then say | |
3906 | -- that they match to avoid junk cascaded errors here. | |
3907 | ||
3908 | elsif not Is_OK_Static_Subtype (T1) | |
3909 | or else not Is_OK_Static_Subtype (T2) | |
3910 | then | |
3911 | return True; | |
3912 | ||
3913 | elsif Is_Real_Type (T1) then | |
3914 | return | |
3915 | (Expr_Value_R (LB1) = Expr_Value_R (LB2)) | |
3916 | and then | |
3917 | (Expr_Value_R (HB1) = Expr_Value_R (HB2)); | |
3918 | ||
3919 | else | |
3920 | return | |
3921 | Expr_Value (LB1) = Expr_Value (LB2) | |
3922 | and then | |
3923 | Expr_Value (HB1) = Expr_Value (HB2); | |
3924 | end if; | |
3925 | end if; | |
3926 | end; | |
3927 | ||
3928 | -- Type with discriminants | |
3929 | ||
3930 | elsif Has_Discriminants (T1) or else Has_Discriminants (T2) then | |
6eaf4095 | 3931 | |
c2bf339e GD |
3932 | -- Because of view exchanges in multiple instantiations, conformance |
3933 | -- checking might try to match a partial view of a type with no | |
3934 | -- discriminants with a full view that has defaulted discriminants. | |
3935 | -- In such a case, use the discriminant constraint of the full view, | |
3936 | -- which must exist because we know that the two subtypes have the | |
3937 | -- same base type. | |
6eaf4095 | 3938 | |
996ae0b0 | 3939 | if Has_Discriminants (T1) /= Has_Discriminants (T2) then |
c2bf339e GD |
3940 | if In_Instance then |
3941 | if Is_Private_Type (T2) | |
3942 | and then Present (Full_View (T2)) | |
3943 | and then Has_Discriminants (Full_View (T2)) | |
3944 | then | |
3945 | return Subtypes_Statically_Match (T1, Full_View (T2)); | |
3946 | ||
3947 | elsif Is_Private_Type (T1) | |
3948 | and then Present (Full_View (T1)) | |
3949 | and then Has_Discriminants (Full_View (T1)) | |
3950 | then | |
3951 | return Subtypes_Statically_Match (Full_View (T1), T2); | |
3952 | ||
3953 | else | |
3954 | return False; | |
3955 | end if; | |
6eaf4095 ES |
3956 | else |
3957 | return False; | |
3958 | end if; | |
996ae0b0 RK |
3959 | end if; |
3960 | ||
3961 | declare | |
3962 | DL1 : constant Elist_Id := Discriminant_Constraint (T1); | |
3963 | DL2 : constant Elist_Id := Discriminant_Constraint (T2); | |
3964 | ||
3965 | DA1 : Elmt_Id := First_Elmt (DL1); | |
3966 | DA2 : Elmt_Id := First_Elmt (DL2); | |
3967 | ||
3968 | begin | |
3969 | if DL1 = DL2 then | |
3970 | return True; | |
3971 | ||
3972 | elsif Is_Constrained (T1) /= Is_Constrained (T2) then | |
3973 | return False; | |
3974 | end if; | |
3975 | ||
3976 | while Present (DA1) loop | |
3977 | declare | |
3978 | Expr1 : constant Node_Id := Node (DA1); | |
3979 | Expr2 : constant Node_Id := Node (DA2); | |
3980 | ||
3981 | begin | |
3982 | if not Is_Static_Expression (Expr1) | |
3983 | or else not Is_Static_Expression (Expr2) | |
3984 | then | |
3985 | return False; | |
3986 | ||
3987 | -- If either expression raised a constraint error, | |
3988 | -- consider the expressions as matching, since this | |
3989 | -- helps to prevent cascading errors. | |
3990 | ||
3991 | elsif Raises_Constraint_Error (Expr1) | |
3992 | or else Raises_Constraint_Error (Expr2) | |
3993 | then | |
3994 | null; | |
3995 | ||
3996 | elsif Expr_Value (Expr1) /= Expr_Value (Expr2) then | |
3997 | return False; | |
3998 | end if; | |
3999 | end; | |
4000 | ||
4001 | Next_Elmt (DA1); | |
4002 | Next_Elmt (DA2); | |
4003 | end loop; | |
4004 | end; | |
4005 | ||
4006 | return True; | |
4007 | ||
82c80734 | 4008 | -- A definite type does not match an indefinite or classwide type |
0356699b RD |
4009 | -- However, a generic type with unknown discriminants may be |
4010 | -- instantiated with a type with no discriminants, and conformance | |
4011 | -- checking on an inherited operation may compare the actual with | |
4012 | -- the subtype that renames it in the instance. | |
996ae0b0 RK |
4013 | |
4014 | elsif | |
4015 | Has_Unknown_Discriminants (T1) /= Has_Unknown_Discriminants (T2) | |
4016 | then | |
0356699b RD |
4017 | if Is_Generic_Actual_Type (T1) |
4018 | and then Etype (T1) = T2 | |
4019 | then | |
4020 | return True; | |
4021 | else | |
4022 | return False; | |
4023 | end if; | |
996ae0b0 RK |
4024 | |
4025 | -- Array type | |
4026 | ||
4027 | elsif Is_Array_Type (T1) then | |
4028 | ||
4029 | -- If either subtype is unconstrained then both must be, | |
4030 | -- and if both are unconstrained then no further checking | |
4031 | -- is needed. | |
4032 | ||
4033 | if not Is_Constrained (T1) or else not Is_Constrained (T2) then | |
4034 | return not (Is_Constrained (T1) or else Is_Constrained (T2)); | |
4035 | end if; | |
4036 | ||
4037 | -- Both subtypes are constrained, so check that the index | |
4038 | -- subtypes statically match. | |
4039 | ||
4040 | declare | |
4041 | Index1 : Node_Id := First_Index (T1); | |
4042 | Index2 : Node_Id := First_Index (T2); | |
4043 | ||
4044 | begin | |
4045 | while Present (Index1) loop | |
4046 | if not | |
4047 | Subtypes_Statically_Match (Etype (Index1), Etype (Index2)) | |
4048 | then | |
4049 | return False; | |
4050 | end if; | |
4051 | ||
4052 | Next_Index (Index1); | |
4053 | Next_Index (Index2); | |
4054 | end loop; | |
4055 | ||
4056 | return True; | |
4057 | end; | |
4058 | ||
4059 | elsif Is_Access_Type (T1) then | |
b5bd964f ES |
4060 | if Can_Never_Be_Null (T1) /= Can_Never_Be_Null (T2) then |
4061 | return False; | |
4062 | ||
4063 | elsif Ekind (T1) = E_Access_Subprogram_Type then | |
4064 | return | |
4065 | Subtype_Conformant | |
4066 | (Designated_Type (T1), | |
4067 | Designated_Type (T1)); | |
4068 | else | |
4069 | return | |
4070 | Subtypes_Statically_Match | |
4071 | (Designated_Type (T1), | |
4072 | Designated_Type (T2)) | |
4073 | and then Is_Access_Constant (T1) = Is_Access_Constant (T2); | |
4074 | end if; | |
996ae0b0 RK |
4075 | |
4076 | -- All other types definitely match | |
4077 | ||
4078 | else | |
4079 | return True; | |
4080 | end if; | |
4081 | end Subtypes_Statically_Match; | |
4082 | ||
4083 | ---------- | |
4084 | -- Test -- | |
4085 | ---------- | |
4086 | ||
4087 | function Test (Cond : Boolean) return Uint is | |
4088 | begin | |
4089 | if Cond then | |
4090 | return Uint_1; | |
4091 | else | |
4092 | return Uint_0; | |
4093 | end if; | |
4094 | end Test; | |
4095 | ||
4096 | --------------------------------- | |
4097 | -- Test_Expression_Is_Foldable -- | |
4098 | --------------------------------- | |
4099 | ||
4100 | -- One operand case | |
4101 | ||
4102 | procedure Test_Expression_Is_Foldable | |
4103 | (N : Node_Id; | |
4104 | Op1 : Node_Id; | |
4105 | Stat : out Boolean; | |
4106 | Fold : out Boolean) | |
4107 | is | |
4108 | begin | |
4109 | Stat := False; | |
0356699b RD |
4110 | Fold := False; |
4111 | ||
4112 | if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then | |
4113 | return; | |
4114 | end if; | |
996ae0b0 RK |
4115 | |
4116 | -- If operand is Any_Type, just propagate to result and do not | |
4117 | -- try to fold, this prevents cascaded errors. | |
4118 | ||
4119 | if Etype (Op1) = Any_Type then | |
4120 | Set_Etype (N, Any_Type); | |
996ae0b0 RK |
4121 | return; |
4122 | ||
4123 | -- If operand raises constraint error, then replace node N with the | |
4124 | -- raise constraint error node, and we are obviously not foldable. | |
4125 | -- Note that this replacement inherits the Is_Static_Expression flag | |
4126 | -- from the operand. | |
4127 | ||
4128 | elsif Raises_Constraint_Error (Op1) then | |
4129 | Rewrite_In_Raise_CE (N, Op1); | |
996ae0b0 RK |
4130 | return; |
4131 | ||
4132 | -- If the operand is not static, then the result is not static, and | |
4133 | -- all we have to do is to check the operand since it is now known | |
4134 | -- to appear in a non-static context. | |
4135 | ||
4136 | elsif not Is_Static_Expression (Op1) then | |
4137 | Check_Non_Static_Context (Op1); | |
4138 | Fold := Compile_Time_Known_Value (Op1); | |
4139 | return; | |
4140 | ||
4141 | -- An expression of a formal modular type is not foldable because | |
4142 | -- the modulus is unknown. | |
4143 | ||
4144 | elsif Is_Modular_Integer_Type (Etype (Op1)) | |
4145 | and then Is_Generic_Type (Etype (Op1)) | |
4146 | then | |
4147 | Check_Non_Static_Context (Op1); | |
996ae0b0 RK |
4148 | return; |
4149 | ||
4150 | -- Here we have the case of an operand whose type is OK, which is | |
4151 | -- static, and which does not raise constraint error, we can fold. | |
4152 | ||
4153 | else | |
4154 | Set_Is_Static_Expression (N); | |
4155 | Fold := True; | |
4156 | Stat := True; | |
4157 | end if; | |
4158 | end Test_Expression_Is_Foldable; | |
4159 | ||
4160 | -- Two operand case | |
4161 | ||
4162 | procedure Test_Expression_Is_Foldable | |
4163 | (N : Node_Id; | |
4164 | Op1 : Node_Id; | |
4165 | Op2 : Node_Id; | |
4166 | Stat : out Boolean; | |
4167 | Fold : out Boolean) | |
4168 | is | |
4169 | Rstat : constant Boolean := Is_Static_Expression (Op1) | |
4170 | and then Is_Static_Expression (Op2); | |
4171 | ||
4172 | begin | |
4173 | Stat := False; | |
0356699b RD |
4174 | Fold := False; |
4175 | ||
4176 | if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then | |
4177 | return; | |
4178 | end if; | |
996ae0b0 RK |
4179 | |
4180 | -- If either operand is Any_Type, just propagate to result and | |
4181 | -- do not try to fold, this prevents cascaded errors. | |
4182 | ||
4183 | if Etype (Op1) = Any_Type or else Etype (Op2) = Any_Type then | |
4184 | Set_Etype (N, Any_Type); | |
996ae0b0 RK |
4185 | return; |
4186 | ||
4187 | -- If left operand raises constraint error, then replace node N with | |
4188 | -- the raise constraint error node, and we are obviously not foldable. | |
4189 | -- Is_Static_Expression is set from the two operands in the normal way, | |
4190 | -- and we check the right operand if it is in a non-static context. | |
4191 | ||
4192 | elsif Raises_Constraint_Error (Op1) then | |
4193 | if not Rstat then | |
4194 | Check_Non_Static_Context (Op2); | |
4195 | end if; | |
4196 | ||
4197 | Rewrite_In_Raise_CE (N, Op1); | |
4198 | Set_Is_Static_Expression (N, Rstat); | |
996ae0b0 RK |
4199 | return; |
4200 | ||
4201 | -- Similar processing for the case of the right operand. Note that | |
4202 | -- we don't use this routine for the short-circuit case, so we do | |
4203 | -- not have to worry about that special case here. | |
4204 | ||
4205 | elsif Raises_Constraint_Error (Op2) then | |
4206 | if not Rstat then | |
4207 | Check_Non_Static_Context (Op1); | |
4208 | end if; | |
4209 | ||
4210 | Rewrite_In_Raise_CE (N, Op2); | |
4211 | Set_Is_Static_Expression (N, Rstat); | |
996ae0b0 RK |
4212 | return; |
4213 | ||
82c80734 | 4214 | -- Exclude expressions of a generic modular type, as above |
996ae0b0 RK |
4215 | |
4216 | elsif Is_Modular_Integer_Type (Etype (Op1)) | |
4217 | and then Is_Generic_Type (Etype (Op1)) | |
4218 | then | |
4219 | Check_Non_Static_Context (Op1); | |
996ae0b0 RK |
4220 | return; |
4221 | ||
4222 | -- If result is not static, then check non-static contexts on operands | |
4223 | -- since one of them may be static and the other one may not be static | |
4224 | ||
4225 | elsif not Rstat then | |
4226 | Check_Non_Static_Context (Op1); | |
4227 | Check_Non_Static_Context (Op2); | |
4228 | Fold := Compile_Time_Known_Value (Op1) | |
4229 | and then Compile_Time_Known_Value (Op2); | |
4230 | return; | |
4231 | ||
4232 | -- Else result is static and foldable. Both operands are static, | |
4233 | -- and neither raises constraint error, so we can definitely fold. | |
4234 | ||
4235 | else | |
4236 | Set_Is_Static_Expression (N); | |
4237 | Fold := True; | |
4238 | Stat := True; | |
4239 | return; | |
4240 | end if; | |
4241 | end Test_Expression_Is_Foldable; | |
4242 | ||
4243 | -------------- | |
4244 | -- To_Bits -- | |
4245 | -------------- | |
4246 | ||
4247 | procedure To_Bits (U : Uint; B : out Bits) is | |
4248 | begin | |
4249 | for J in 0 .. B'Last loop | |
4250 | B (J) := (U / (2 ** J)) mod 2 /= 0; | |
4251 | end loop; | |
4252 | end To_Bits; | |
4253 | ||
fbf5a39b AC |
4254 | -------------------- |
4255 | -- Why_Not_Static -- | |
4256 | -------------------- | |
4257 | ||
4258 | procedure Why_Not_Static (Expr : Node_Id) is | |
4259 | N : constant Node_Id := Original_Node (Expr); | |
4260 | Typ : Entity_Id; | |
4261 | E : Entity_Id; | |
4262 | ||
4263 | procedure Why_Not_Static_List (L : List_Id); | |
4264 | -- A version that can be called on a list of expressions. Finds | |
4265 | -- all non-static violations in any element of the list. | |
4266 | ||
4267 | ------------------------- | |
4268 | -- Why_Not_Static_List -- | |
4269 | ------------------------- | |
4270 | ||
4271 | procedure Why_Not_Static_List (L : List_Id) is | |
4272 | N : Node_Id; | |
4273 | ||
4274 | begin | |
4275 | if Is_Non_Empty_List (L) then | |
4276 | N := First (L); | |
4277 | while Present (N) loop | |
4278 | Why_Not_Static (N); | |
4279 | Next (N); | |
4280 | end loop; | |
4281 | end if; | |
4282 | end Why_Not_Static_List; | |
4283 | ||
4284 | -- Start of processing for Why_Not_Static | |
4285 | ||
4286 | begin | |
4287 | -- If in ACATS mode (debug flag 2), then suppress all these | |
4288 | -- messages, this avoids massive updates to the ACATS base line. | |
4289 | ||
4290 | if Debug_Flag_2 then | |
4291 | return; | |
4292 | end if; | |
4293 | ||
4294 | -- Ignore call on error or empty node | |
4295 | ||
4296 | if No (Expr) or else Nkind (Expr) = N_Error then | |
4297 | return; | |
4298 | end if; | |
4299 | ||
4300 | -- Preprocessing for sub expressions | |
4301 | ||
4302 | if Nkind (Expr) in N_Subexpr then | |
4303 | ||
4304 | -- Nothing to do if expression is static | |
4305 | ||
4306 | if Is_OK_Static_Expression (Expr) then | |
4307 | return; | |
4308 | end if; | |
4309 | ||
4310 | -- Test for constraint error raised | |
4311 | ||
4312 | if Raises_Constraint_Error (Expr) then | |
4313 | Error_Msg_N | |
4314 | ("expression raises exception, cannot be static " & | |
4315 | "('R'M 4.9(34))!", N); | |
4316 | return; | |
4317 | end if; | |
4318 | ||
4319 | -- If no type, then something is pretty wrong, so ignore | |
4320 | ||
4321 | Typ := Etype (Expr); | |
4322 | ||
4323 | if No (Typ) then | |
4324 | return; | |
4325 | end if; | |
4326 | ||
4327 | -- Type must be scalar or string type | |
4328 | ||
4329 | if not Is_Scalar_Type (Typ) | |
4330 | and then not Is_String_Type (Typ) | |
4331 | then | |
4332 | Error_Msg_N | |
4333 | ("static expression must have scalar or string type " & | |
4334 | "('R'M 4.9(2))!", N); | |
4335 | return; | |
4336 | end if; | |
4337 | end if; | |
4338 | ||
4339 | -- If we got through those checks, test particular node kind | |
4340 | ||
4341 | case Nkind (N) is | |
4342 | when N_Expanded_Name | N_Identifier | N_Operator_Symbol => | |
4343 | E := Entity (N); | |
4344 | ||
4345 | if Is_Named_Number (E) then | |
4346 | null; | |
4347 | ||
4348 | elsif Ekind (E) = E_Constant then | |
4349 | if not Is_Static_Expression (Constant_Value (E)) then | |
4350 | Error_Msg_NE | |
4351 | ("& is not a static constant ('R'M 4.9(5))!", N, E); | |
4352 | end if; | |
4353 | ||
4354 | else | |
4355 | Error_Msg_NE | |
4356 | ("& is not static constant or named number " & | |
4357 | "('R'M 4.9(5))!", N, E); | |
4358 | end if; | |
4359 | ||
4360 | when N_Binary_Op | N_And_Then | N_Or_Else | N_In | N_Not_In => | |
4361 | if Nkind (N) in N_Op_Shift then | |
4362 | Error_Msg_N | |
4363 | ("shift functions are never static ('R'M 4.9(6,18))!", N); | |
4364 | ||
4365 | else | |
4366 | Why_Not_Static (Left_Opnd (N)); | |
4367 | Why_Not_Static (Right_Opnd (N)); | |
4368 | end if; | |
4369 | ||
4370 | when N_Unary_Op => | |
4371 | Why_Not_Static (Right_Opnd (N)); | |
4372 | ||
4373 | when N_Attribute_Reference => | |
4374 | Why_Not_Static_List (Expressions (N)); | |
4375 | ||
4376 | E := Etype (Prefix (N)); | |
4377 | ||
4378 | if E = Standard_Void_Type then | |
4379 | return; | |
4380 | end if; | |
4381 | ||
4382 | -- Special case non-scalar'Size since this is a common error | |
4383 | ||
4384 | if Attribute_Name (N) = Name_Size then | |
4385 | Error_Msg_N | |
4386 | ("size attribute is only static for scalar type " & | |
4387 | "('R'M 4.9(7,8))", N); | |
4388 | ||
4389 | -- Flag array cases | |
4390 | ||
4391 | elsif Is_Array_Type (E) then | |
4392 | if Attribute_Name (N) /= Name_First | |
4393 | and then | |
4394 | Attribute_Name (N) /= Name_Last | |
4395 | and then | |
4396 | Attribute_Name (N) /= Name_Length | |
4397 | then | |
4398 | Error_Msg_N | |
4399 | ("static array attribute must be Length, First, or Last " & | |
4400 | "('R'M 4.9(8))!", N); | |
4401 | ||
4402 | -- Since we know the expression is not-static (we already | |
4403 | -- tested for this, must mean array is not static). | |
4404 | ||
4405 | else | |
4406 | Error_Msg_N | |
4407 | ("prefix is non-static array ('R'M 4.9(8))!", Prefix (N)); | |
4408 | end if; | |
4409 | ||
4410 | return; | |
4411 | ||
4412 | -- Special case generic types, since again this is a common | |
4413 | -- source of confusion. | |
4414 | ||
4415 | elsif Is_Generic_Actual_Type (E) | |
4416 | or else | |
4417 | Is_Generic_Type (E) | |
4418 | then | |
4419 | Error_Msg_N | |
4420 | ("attribute of generic type is never static " & | |
4421 | "('R'M 4.9(7,8))!", N); | |
4422 | ||
4423 | elsif Is_Static_Subtype (E) then | |
4424 | null; | |
4425 | ||
4426 | elsif Is_Scalar_Type (E) then | |
4427 | Error_Msg_N | |
4428 | ("prefix type for attribute is not static scalar subtype " & | |
4429 | "('R'M 4.9(7))!", N); | |
4430 | ||
4431 | else | |
4432 | Error_Msg_N | |
4433 | ("static attribute must apply to array/scalar type " & | |
4434 | "('R'M 4.9(7,8))!", N); | |
4435 | end if; | |
4436 | ||
4437 | when N_String_Literal => | |
4438 | Error_Msg_N | |
4439 | ("subtype of string literal is non-static ('R'M 4.9(4))!", N); | |
4440 | ||
4441 | when N_Explicit_Dereference => | |
4442 | Error_Msg_N | |
4443 | ("explicit dereference is never static ('R'M 4.9)!", N); | |
4444 | ||
4445 | when N_Function_Call => | |
4446 | Why_Not_Static_List (Parameter_Associations (N)); | |
4447 | Error_Msg_N ("non-static function call ('R'M 4.9(6,18))!", N); | |
4448 | ||
4449 | when N_Parameter_Association => | |
4450 | Why_Not_Static (Explicit_Actual_Parameter (N)); | |
4451 | ||
4452 | when N_Indexed_Component => | |
4453 | Error_Msg_N | |
4454 | ("indexed component is never static ('R'M 4.9)!", N); | |
4455 | ||
4456 | when N_Procedure_Call_Statement => | |
4457 | Error_Msg_N | |
4458 | ("procedure call is never static ('R'M 4.9)!", N); | |
4459 | ||
4460 | when N_Qualified_Expression => | |
4461 | Why_Not_Static (Expression (N)); | |
4462 | ||
4463 | when N_Aggregate | N_Extension_Aggregate => | |
4464 | Error_Msg_N | |
4465 | ("an aggregate is never static ('R'M 4.9)!", N); | |
4466 | ||
4467 | when N_Range => | |
4468 | Why_Not_Static (Low_Bound (N)); | |
4469 | Why_Not_Static (High_Bound (N)); | |
4470 | ||
4471 | when N_Range_Constraint => | |
4472 | Why_Not_Static (Range_Expression (N)); | |
4473 | ||
4474 | when N_Subtype_Indication => | |
4475 | Why_Not_Static (Constraint (N)); | |
4476 | ||
4477 | when N_Selected_Component => | |
4478 | Error_Msg_N | |
4479 | ("selected component is never static ('R'M 4.9)!", N); | |
4480 | ||
4481 | when N_Slice => | |
4482 | Error_Msg_N | |
4483 | ("slice is never static ('R'M 4.9)!", N); | |
4484 | ||
4485 | when N_Type_Conversion => | |
4486 | Why_Not_Static (Expression (N)); | |
4487 | ||
4488 | if not Is_Scalar_Type (Etype (Prefix (N))) | |
4489 | or else not Is_Static_Subtype (Etype (Prefix (N))) | |
4490 | then | |
4491 | Error_Msg_N | |
4492 | ("static conversion requires static scalar subtype result " & | |
4493 | "('R'M 4.9(9))!", N); | |
4494 | end if; | |
4495 | ||
4496 | when N_Unchecked_Type_Conversion => | |
4497 | Error_Msg_N | |
4498 | ("unchecked type conversion is never static ('R'M 4.9)!", N); | |
4499 | ||
4500 | when others => | |
4501 | null; | |
4502 | ||
4503 | end case; | |
4504 | end Why_Not_Static; | |
4505 | ||
996ae0b0 | 4506 | end Sem_Eval; |