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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 | -- -- | |
45fc7ddb | 9 | -- Copyright (C) 1992-2008, 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- -- | |
b5c84c3c | 13 | -- ware Foundation; either version 3, or (at your option) any later ver- -- |
996ae0b0 RK |
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 -- | |
b5c84c3c RD |
18 | -- Public License distributed with GNAT; see file COPYING3. If not, go to -- |
19 | -- http://www.gnu.org/licenses for a complete copy of the license. -- | |
996ae0b0 RK |
20 | -- -- |
21 | -- GNAT was originally developed by the GNAT team at New York University. -- | |
71ff80dc | 22 | -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
996ae0b0 RK |
23 | -- -- |
24 | ------------------------------------------------------------------------------ | |
25 | ||
26 | with Atree; use Atree; | |
27 | with Checks; use Checks; | |
28 | with Debug; use Debug; | |
29 | with Einfo; use Einfo; | |
30 | with Elists; use Elists; | |
31 | with Errout; use Errout; | |
32 | with Eval_Fat; use Eval_Fat; | |
8cbb664e | 33 | with Exp_Util; use Exp_Util; |
0356699b | 34 | with Lib; use Lib; |
13f34a3f | 35 | with Namet; use Namet; |
996ae0b0 RK |
36 | with Nmake; use Nmake; |
37 | with Nlists; use Nlists; | |
38 | with Opt; use Opt; | |
39 | with Sem; use Sem; | |
a4100e55 | 40 | with Sem_Aux; use Sem_Aux; |
996ae0b0 | 41 | with Sem_Cat; use Sem_Cat; |
b5bd964f | 42 | with Sem_Ch6; use Sem_Ch6; |
996ae0b0 RK |
43 | with Sem_Ch8; use Sem_Ch8; |
44 | with Sem_Res; use Sem_Res; | |
45 | with Sem_Util; use Sem_Util; | |
46 | with Sem_Type; use Sem_Type; | |
47 | with Sem_Warn; use Sem_Warn; | |
48 | with Sinfo; use Sinfo; | |
49 | with Snames; use Snames; | |
50 | with Stand; use Stand; | |
51 | with Stringt; use Stringt; | |
07fc65c4 | 52 | with Tbuild; use Tbuild; |
996ae0b0 RK |
53 | |
54 | package body Sem_Eval is | |
55 | ||
56 | ----------------------------------------- | |
57 | -- Handling of Compile Time Evaluation -- | |
58 | ----------------------------------------- | |
59 | ||
60 | -- The compile time evaluation of expressions is distributed over several | |
f3d57416 | 61 | -- Eval_xxx procedures. These procedures are called immediately after |
996ae0b0 RK |
62 | -- a subexpression is resolved and is therefore accomplished in a bottom |
63 | -- up fashion. The flags are synthesized using the following approach. | |
64 | ||
65 | -- Is_Static_Expression is determined by following the detailed rules | |
66 | -- in RM 4.9(4-14). This involves testing the Is_Static_Expression | |
67 | -- flag of the operands in many cases. | |
68 | ||
69 | -- Raises_Constraint_Error is set if any of the operands have the flag | |
70 | -- set or if an attempt to compute the value of the current expression | |
71 | -- results in detection of a runtime constraint error. | |
72 | ||
73 | -- As described in the spec, the requirement is that Is_Static_Expression | |
74 | -- be accurately set, and in addition for nodes for which this flag is set, | |
75 | -- Raises_Constraint_Error must also be set. Furthermore a node which has | |
76 | -- Is_Static_Expression set, and Raises_Constraint_Error clear, then the | |
77 | -- requirement is that the expression value must be precomputed, and the | |
78 | -- node is either a literal, or the name of a constant entity whose value | |
79 | -- is a static expression. | |
80 | ||
81 | -- The general approach is as follows. First compute Is_Static_Expression. | |
82 | -- If the node is not static, then the flag is left off in the node and | |
83 | -- we are all done. Otherwise for a static node, we test if any of the | |
84 | -- operands will raise constraint error, and if so, propagate the flag | |
85 | -- Raises_Constraint_Error to the result node and we are done (since the | |
86 | -- error was already posted at a lower level). | |
87 | ||
88 | -- For the case of a static node whose operands do not raise constraint | |
89 | -- error, we attempt to evaluate the node. If this evaluation succeeds, | |
90 | -- then the node is replaced by the result of this computation. If the | |
91 | -- evaluation raises constraint error, then we rewrite the node with | |
92 | -- Apply_Compile_Time_Constraint_Error to raise the exception and also | |
93 | -- to post appropriate error messages. | |
94 | ||
95 | ---------------- | |
96 | -- Local Data -- | |
97 | ---------------- | |
98 | ||
99 | type Bits is array (Nat range <>) of Boolean; | |
100 | -- Used to convert unsigned (modular) values for folding logical ops | |
101 | ||
07fc65c4 GB |
102 | -- The following definitions are used to maintain a cache of nodes that |
103 | -- have compile time known values. The cache is maintained only for | |
104 | -- discrete types (the most common case), and is populated by calls to | |
105 | -- Compile_Time_Known_Value and Expr_Value, but only used by Expr_Value | |
106 | -- since it is possible for the status to change (in particular it is | |
107 | -- possible for a node to get replaced by a constraint error node). | |
108 | ||
109 | CV_Bits : constant := 5; | |
110 | -- Number of low order bits of Node_Id value used to reference entries | |
111 | -- in the cache table. | |
112 | ||
113 | CV_Cache_Size : constant Nat := 2 ** CV_Bits; | |
114 | -- Size of cache for compile time values | |
115 | ||
116 | subtype CV_Range is Nat range 0 .. CV_Cache_Size; | |
117 | ||
118 | type CV_Entry is record | |
119 | N : Node_Id; | |
120 | V : Uint; | |
121 | end record; | |
122 | ||
123 | type CV_Cache_Array is array (CV_Range) of CV_Entry; | |
124 | ||
125 | CV_Cache : CV_Cache_Array := (others => (Node_High_Bound, Uint_0)); | |
126 | -- This is the actual cache, with entries consisting of node/value pairs, | |
127 | -- and the impossible value Node_High_Bound used for unset entries. | |
128 | ||
996ae0b0 RK |
129 | ----------------------- |
130 | -- Local Subprograms -- | |
131 | ----------------------- | |
132 | ||
996ae0b0 RK |
133 | function From_Bits (B : Bits; T : Entity_Id) return Uint; |
134 | -- Converts a bit string of length B'Length to a Uint value to be used | |
135 | -- for a target of type T, which is a modular type. This procedure | |
136 | -- includes the necessary reduction by the modulus in the case of a | |
137 | -- non-binary modulus (for a binary modulus, the bit string is the | |
138 | -- right length any way so all is well). | |
139 | ||
140 | function Get_String_Val (N : Node_Id) return Node_Id; | |
141 | -- Given a tree node for a folded string or character value, returns | |
142 | -- the corresponding string literal or character literal (one of the | |
143 | -- two must be available, or the operand would not have been marked | |
144 | -- as foldable in the earlier analysis of the operation). | |
145 | ||
07fc65c4 GB |
146 | function OK_Bits (N : Node_Id; Bits : Uint) return Boolean; |
147 | -- Bits represents the number of bits in an integer value to be computed | |
148 | -- (but the value has not been computed yet). If this value in Bits is | |
149 | -- reasonable, a result of True is returned, with the implication that | |
150 | -- the caller should go ahead and complete the calculation. If the value | |
151 | -- in Bits is unreasonably large, then an error is posted on node N, and | |
152 | -- False is returned (and the caller skips the proposed calculation). | |
153 | ||
996ae0b0 RK |
154 | procedure Out_Of_Range (N : Node_Id); |
155 | -- This procedure is called if it is determined that node N, which | |
156 | -- appears in a non-static context, is a compile time known value | |
157 | -- which is outside its range, i.e. the range of Etype. This is used | |
158 | -- in contexts where this is an illegality if N is static, and should | |
159 | -- generate a warning otherwise. | |
160 | ||
161 | procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id); | |
162 | -- N and Exp are nodes representing an expression, Exp is known | |
163 | -- to raise CE. N is rewritten in term of Exp in the optimal way. | |
164 | ||
165 | function String_Type_Len (Stype : Entity_Id) return Uint; | |
166 | -- Given a string type, determines the length of the index type, or, | |
167 | -- if this index type is non-static, the length of the base type of | |
168 | -- this index type. Note that if the string type is itself static, | |
169 | -- then the index type is static, so the second case applies only | |
170 | -- if the string type passed is non-static. | |
171 | ||
172 | function Test (Cond : Boolean) return Uint; | |
173 | pragma Inline (Test); | |
174 | -- This function simply returns the appropriate Boolean'Pos value | |
175 | -- corresponding to the value of Cond as a universal integer. It is | |
176 | -- used for producing the result of the static evaluation of the | |
177 | -- logical operators | |
178 | ||
179 | procedure Test_Expression_Is_Foldable | |
180 | (N : Node_Id; | |
181 | Op1 : Node_Id; | |
182 | Stat : out Boolean; | |
183 | Fold : out Boolean); | |
184 | -- Tests to see if expression N whose single operand is Op1 is foldable, | |
185 | -- i.e. the operand value is known at compile time. If the operation is | |
186 | -- foldable, then Fold is True on return, and Stat indicates whether | |
187 | -- the result is static (i.e. both operands were static). Note that it | |
188 | -- is quite possible for Fold to be True, and Stat to be False, since | |
189 | -- there are cases in which we know the value of an operand even though | |
190 | -- it is not technically static (e.g. the static lower bound of a range | |
191 | -- whose upper bound is non-static). | |
192 | -- | |
3d5952be | 193 | -- If Stat is set False on return, then Test_Expression_Is_Foldable makes a |
996ae0b0 RK |
194 | -- call to Check_Non_Static_Context on the operand. If Fold is False on |
195 | -- return, then all processing is complete, and the caller should | |
196 | -- return, since there is nothing else to do. | |
197 | ||
198 | procedure Test_Expression_Is_Foldable | |
199 | (N : Node_Id; | |
200 | Op1 : Node_Id; | |
201 | Op2 : Node_Id; | |
202 | Stat : out Boolean; | |
203 | Fold : out Boolean); | |
204 | -- Same processing, except applies to an expression N with two operands | |
205 | -- Op1 and Op2. | |
206 | ||
207 | procedure To_Bits (U : Uint; B : out Bits); | |
208 | -- Converts a Uint value to a bit string of length B'Length | |
209 | ||
210 | ------------------------------ | |
211 | -- Check_Non_Static_Context -- | |
212 | ------------------------------ | |
213 | ||
214 | procedure Check_Non_Static_Context (N : Node_Id) is | |
fbf5a39b AC |
215 | T : constant Entity_Id := Etype (N); |
216 | Checks_On : constant Boolean := | |
996ae0b0 RK |
217 | not Index_Checks_Suppressed (T) |
218 | and not Range_Checks_Suppressed (T); | |
219 | ||
220 | begin | |
fbf5a39b | 221 | -- Ignore cases of non-scalar types or error types |
996ae0b0 | 222 | |
fbf5a39b | 223 | if T = Any_Type or else not Is_Scalar_Type (T) then |
996ae0b0 | 224 | return; |
fbf5a39b | 225 | end if; |
996ae0b0 | 226 | |
fbf5a39b AC |
227 | -- At this stage we have a scalar type. If we have an expression |
228 | -- that raises CE, then we already issued a warning or error msg | |
229 | -- so there is nothing more to be done in this routine. | |
230 | ||
231 | if Raises_Constraint_Error (N) then | |
232 | return; | |
233 | end if; | |
234 | ||
235 | -- Now we have a scalar type which is not marked as raising a | |
236 | -- constraint error exception. The main purpose of this routine | |
237 | -- is to deal with static expressions appearing in a non-static | |
238 | -- context. That means that if we do not have a static expression | |
239 | -- then there is not much to do. The one case that we deal with | |
240 | -- here is that if we have a floating-point value that is out of | |
241 | -- range, then we post a warning that an infinity will result. | |
242 | ||
243 | if not Is_Static_Expression (N) then | |
244 | if Is_Floating_Point_Type (T) | |
c800f862 | 245 | and then Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) |
fbf5a39b AC |
246 | then |
247 | Error_Msg_N | |
248 | ("?float value out of range, infinity will be generated", N); | |
249 | end if; | |
996ae0b0 | 250 | |
996ae0b0 RK |
251 | return; |
252 | end if; | |
253 | ||
254 | -- Here we have the case of outer level static expression of | |
255 | -- scalar type, where the processing of this procedure is needed. | |
256 | ||
257 | -- For real types, this is where we convert the value to a machine | |
258 | -- number (see RM 4.9(38)). Also see ACVC test C490001. We should | |
259 | -- only need to do this if the parent is a constant declaration, | |
260 | -- since in other cases, gigi should do the necessary conversion | |
261 | -- correctly, but experimentation shows that this is not the case | |
262 | -- on all machines, in particular if we do not convert all literals | |
263 | -- to machine values in non-static contexts, then ACVC test C490001 | |
264 | -- fails on Sparc/Solaris and SGI/Irix. | |
265 | ||
266 | if Nkind (N) = N_Real_Literal | |
267 | and then not Is_Machine_Number (N) | |
268 | and then not Is_Generic_Type (Etype (N)) | |
269 | and then Etype (N) /= Universal_Real | |
996ae0b0 RK |
270 | then |
271 | -- Check that value is in bounds before converting to machine | |
272 | -- number, so as not to lose case where value overflows in the | |
273 | -- least significant bit or less. See B490001. | |
274 | ||
c800f862 | 275 | if Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) then |
996ae0b0 RK |
276 | Out_Of_Range (N); |
277 | return; | |
278 | end if; | |
279 | ||
280 | -- Note: we have to copy the node, to avoid problems with conformance | |
281 | -- of very similar numbers (see ACVC tests B4A010C and B63103A). | |
282 | ||
283 | Rewrite (N, New_Copy (N)); | |
284 | ||
285 | if not Is_Floating_Point_Type (T) then | |
286 | Set_Realval | |
287 | (N, Corresponding_Integer_Value (N) * Small_Value (T)); | |
288 | ||
289 | elsif not UR_Is_Zero (Realval (N)) then | |
996ae0b0 | 290 | |
fbf5a39b AC |
291 | -- Note: even though RM 4.9(38) specifies biased rounding, |
292 | -- this has been modified by AI-100 in order to prevent | |
293 | -- confusing differences in rounding between static and | |
294 | -- non-static expressions. AI-100 specifies that the effect | |
295 | -- of such rounding is implementation dependent, and in GNAT | |
296 | -- we round to nearest even to match the run-time behavior. | |
996ae0b0 | 297 | |
fbf5a39b AC |
298 | Set_Realval |
299 | (N, Machine (Base_Type (T), Realval (N), Round_Even, N)); | |
996ae0b0 RK |
300 | end if; |
301 | ||
302 | Set_Is_Machine_Number (N); | |
303 | end if; | |
304 | ||
305 | -- Check for out of range universal integer. This is a non-static | |
306 | -- context, so the integer value must be in range of the runtime | |
307 | -- representation of universal integers. | |
308 | ||
309 | -- We do this only within an expression, because that is the only | |
310 | -- case in which non-static universal integer values can occur, and | |
311 | -- furthermore, Check_Non_Static_Context is currently (incorrectly???) | |
312 | -- called in contexts like the expression of a number declaration where | |
313 | -- we certainly want to allow out of range values. | |
314 | ||
315 | if Etype (N) = Universal_Integer | |
316 | and then Nkind (N) = N_Integer_Literal | |
317 | and then Nkind (Parent (N)) in N_Subexpr | |
318 | and then | |
319 | (Intval (N) < Expr_Value (Type_Low_Bound (Universal_Integer)) | |
320 | or else | |
321 | Intval (N) > Expr_Value (Type_High_Bound (Universal_Integer))) | |
322 | then | |
323 | Apply_Compile_Time_Constraint_Error | |
07fc65c4 GB |
324 | (N, "non-static universal integer value out of range?", |
325 | CE_Range_Check_Failed); | |
996ae0b0 RK |
326 | |
327 | -- Check out of range of base type | |
328 | ||
c800f862 | 329 | elsif Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) then |
996ae0b0 RK |
330 | Out_Of_Range (N); |
331 | ||
c800f862 RD |
332 | -- Give warning if outside subtype (where one or both of the bounds of |
333 | -- the subtype is static). This warning is omitted if the expression | |
334 | -- appears in a range that could be null (warnings are handled elsewhere | |
335 | -- for this case). | |
996ae0b0 RK |
336 | |
337 | elsif T /= Base_Type (T) | |
338 | and then Nkind (Parent (N)) /= N_Range | |
339 | then | |
c800f862 | 340 | if Is_In_Range (N, T, Assume_Valid => True) then |
996ae0b0 RK |
341 | null; |
342 | ||
c800f862 | 343 | elsif Is_Out_Of_Range (N, T, Assume_Valid => True) then |
996ae0b0 | 344 | Apply_Compile_Time_Constraint_Error |
07fc65c4 | 345 | (N, "value not in range of}?", CE_Range_Check_Failed); |
996ae0b0 RK |
346 | |
347 | elsif Checks_On then | |
348 | Enable_Range_Check (N); | |
349 | ||
350 | else | |
351 | Set_Do_Range_Check (N, False); | |
352 | end if; | |
353 | end if; | |
354 | end Check_Non_Static_Context; | |
355 | ||
356 | --------------------------------- | |
357 | -- Check_String_Literal_Length -- | |
358 | --------------------------------- | |
359 | ||
360 | procedure Check_String_Literal_Length (N : Node_Id; Ttype : Entity_Id) is | |
361 | begin | |
362 | if not Raises_Constraint_Error (N) | |
363 | and then Is_Constrained (Ttype) | |
364 | then | |
365 | if | |
366 | UI_From_Int (String_Length (Strval (N))) /= String_Type_Len (Ttype) | |
367 | then | |
368 | Apply_Compile_Time_Constraint_Error | |
369 | (N, "string length wrong for}?", | |
07fc65c4 | 370 | CE_Length_Check_Failed, |
996ae0b0 RK |
371 | Ent => Ttype, |
372 | Typ => Ttype); | |
373 | end if; | |
374 | end if; | |
375 | end Check_String_Literal_Length; | |
376 | ||
377 | -------------------------- | |
378 | -- Compile_Time_Compare -- | |
379 | -------------------------- | |
380 | ||
fbf5a39b | 381 | function Compile_Time_Compare |
1c7717c3 AC |
382 | (L, R : Node_Id; |
383 | Assume_Valid : Boolean; | |
384 | Rec : Boolean := False) return Compare_Result | |
fbf5a39b | 385 | is |
1c7717c3 AC |
386 | Ltyp : Entity_Id := Etype (L); |
387 | Rtyp : Entity_Id := Etype (R); | |
388 | -- These get reset to the base type for the case of entities where | |
389 | -- Is_Known_Valid is not set. This takes care of handling possible | |
390 | -- invalid representations using the value of the base type, in | |
391 | -- accordance with RM 13.9.1(10). | |
996ae0b0 RK |
392 | |
393 | procedure Compare_Decompose | |
394 | (N : Node_Id; | |
395 | R : out Node_Id; | |
396 | V : out Uint); | |
b49365b2 RD |
397 | -- This procedure decomposes the node N into an expression node and a |
398 | -- signed offset, so that the value of N is equal to the value of R plus | |
399 | -- the value V (which may be negative). If no such decomposition is | |
400 | -- possible, then on return R is a copy of N, and V is set to zero. | |
996ae0b0 RK |
401 | |
402 | function Compare_Fixup (N : Node_Id) return Node_Id; | |
b49365b2 RD |
403 | -- This function deals with replacing 'Last and 'First references with |
404 | -- their corresponding type bounds, which we then can compare. The | |
405 | -- argument is the original node, the result is the identity, unless we | |
406 | -- have a 'Last/'First reference in which case the value returned is the | |
407 | -- appropriate type bound. | |
996ae0b0 RK |
408 | |
409 | function Is_Same_Value (L, R : Node_Id) return Boolean; | |
410 | -- Returns True iff L and R represent expressions that definitely | |
411 | -- have identical (but not necessarily compile time known) values | |
412 | -- Indeed the caller is expected to have already dealt with the | |
413 | -- cases of compile time known values, so these are not tested here. | |
414 | ||
415 | ----------------------- | |
416 | -- Compare_Decompose -- | |
417 | ----------------------- | |
418 | ||
419 | procedure Compare_Decompose | |
420 | (N : Node_Id; | |
421 | R : out Node_Id; | |
422 | V : out Uint) | |
423 | is | |
424 | begin | |
425 | if Nkind (N) = N_Op_Add | |
426 | and then Nkind (Right_Opnd (N)) = N_Integer_Literal | |
427 | then | |
428 | R := Left_Opnd (N); | |
429 | V := Intval (Right_Opnd (N)); | |
430 | return; | |
431 | ||
432 | elsif Nkind (N) = N_Op_Subtract | |
433 | and then Nkind (Right_Opnd (N)) = N_Integer_Literal | |
434 | then | |
435 | R := Left_Opnd (N); | |
436 | V := UI_Negate (Intval (Right_Opnd (N))); | |
437 | return; | |
438 | ||
439 | elsif Nkind (N) = N_Attribute_Reference then | |
996ae0b0 RK |
440 | if Attribute_Name (N) = Name_Succ then |
441 | R := First (Expressions (N)); | |
442 | V := Uint_1; | |
443 | return; | |
444 | ||
445 | elsif Attribute_Name (N) = Name_Pred then | |
446 | R := First (Expressions (N)); | |
447 | V := Uint_Minus_1; | |
448 | return; | |
449 | end if; | |
450 | end if; | |
451 | ||
452 | R := N; | |
453 | V := Uint_0; | |
454 | end Compare_Decompose; | |
455 | ||
456 | ------------------- | |
457 | -- Compare_Fixup -- | |
458 | ------------------- | |
459 | ||
460 | function Compare_Fixup (N : Node_Id) return Node_Id is | |
461 | Indx : Node_Id; | |
462 | Xtyp : Entity_Id; | |
463 | Subs : Nat; | |
464 | ||
465 | begin | |
466 | if Nkind (N) = N_Attribute_Reference | |
467 | and then (Attribute_Name (N) = Name_First | |
468 | or else | |
469 | Attribute_Name (N) = Name_Last) | |
470 | then | |
471 | Xtyp := Etype (Prefix (N)); | |
472 | ||
473 | -- If we have no type, then just abandon the attempt to do | |
474 | -- a fixup, this is probably the result of some other error. | |
475 | ||
476 | if No (Xtyp) then | |
477 | return N; | |
478 | end if; | |
479 | ||
480 | -- Dereference an access type | |
481 | ||
482 | if Is_Access_Type (Xtyp) then | |
483 | Xtyp := Designated_Type (Xtyp); | |
484 | end if; | |
485 | ||
486 | -- If we don't have an array type at this stage, something | |
487 | -- is peculiar, e.g. another error, and we abandon the attempt | |
488 | -- at a fixup. | |
489 | ||
490 | if not Is_Array_Type (Xtyp) then | |
491 | return N; | |
492 | end if; | |
493 | ||
494 | -- Ignore unconstrained array, since bounds are not meaningful | |
495 | ||
496 | if not Is_Constrained (Xtyp) then | |
497 | return N; | |
498 | end if; | |
499 | ||
c3de5c4c ES |
500 | if Ekind (Xtyp) = E_String_Literal_Subtype then |
501 | if Attribute_Name (N) = Name_First then | |
502 | return String_Literal_Low_Bound (Xtyp); | |
503 | ||
504 | else -- Attribute_Name (N) = Name_Last | |
505 | return Make_Integer_Literal (Sloc (N), | |
506 | Intval => Intval (String_Literal_Low_Bound (Xtyp)) | |
507 | + String_Literal_Length (Xtyp)); | |
508 | end if; | |
509 | end if; | |
510 | ||
996ae0b0 RK |
511 | -- Find correct index type |
512 | ||
513 | Indx := First_Index (Xtyp); | |
514 | ||
515 | if Present (Expressions (N)) then | |
516 | Subs := UI_To_Int (Expr_Value (First (Expressions (N)))); | |
517 | ||
518 | for J in 2 .. Subs loop | |
519 | Indx := Next_Index (Indx); | |
520 | end loop; | |
521 | end if; | |
522 | ||
523 | Xtyp := Etype (Indx); | |
524 | ||
525 | if Attribute_Name (N) = Name_First then | |
526 | return Type_Low_Bound (Xtyp); | |
527 | ||
528 | else -- Attribute_Name (N) = Name_Last | |
529 | return Type_High_Bound (Xtyp); | |
530 | end if; | |
531 | end if; | |
532 | ||
533 | return N; | |
534 | end Compare_Fixup; | |
535 | ||
536 | ------------------- | |
537 | -- Is_Same_Value -- | |
538 | ------------------- | |
539 | ||
540 | function Is_Same_Value (L, R : Node_Id) return Boolean is | |
541 | Lf : constant Node_Id := Compare_Fixup (L); | |
542 | Rf : constant Node_Id := Compare_Fixup (R); | |
543 | ||
fbf5a39b AC |
544 | function Is_Same_Subscript (L, R : List_Id) return Boolean; |
545 | -- L, R are the Expressions values from two attribute nodes | |
546 | -- for First or Last attributes. Either may be set to No_List | |
547 | -- if no expressions are present (indicating subscript 1). | |
548 | -- The result is True if both expressions represent the same | |
549 | -- subscript (note that one case is where one subscript is | |
550 | -- missing and the other is explicitly set to 1). | |
551 | ||
552 | ----------------------- | |
553 | -- Is_Same_Subscript -- | |
554 | ----------------------- | |
555 | ||
556 | function Is_Same_Subscript (L, R : List_Id) return Boolean is | |
557 | begin | |
558 | if L = No_List then | |
559 | if R = No_List then | |
560 | return True; | |
561 | else | |
562 | return Expr_Value (First (R)) = Uint_1; | |
563 | end if; | |
564 | ||
565 | else | |
566 | if R = No_List then | |
567 | return Expr_Value (First (L)) = Uint_1; | |
568 | else | |
569 | return Expr_Value (First (L)) = Expr_Value (First (R)); | |
570 | end if; | |
571 | end if; | |
572 | end Is_Same_Subscript; | |
573 | ||
574 | -- Start of processing for Is_Same_Value | |
575 | ||
996ae0b0 | 576 | begin |
b49365b2 | 577 | -- Values are the same if they refer to the same entity and the |
c800f862 RD |
578 | -- entity is non-volatile. This does not however apply to Float |
579 | -- types, since we may have two NaN values and they should never | |
580 | -- compare equal. | |
996ae0b0 | 581 | |
b49365b2 RD |
582 | if Nkind_In (Lf, N_Identifier, N_Expanded_Name) |
583 | and then Nkind_In (Rf, N_Identifier, N_Expanded_Name) | |
996ae0b0 | 584 | and then Entity (Lf) = Entity (Rf) |
b49365b2 | 585 | and then Present (Entity (Lf)) |
fbf5a39b | 586 | and then not Is_Floating_Point_Type (Etype (L)) |
c800f862 RD |
587 | and then not Is_Volatile_Reference (L) |
588 | and then not Is_Volatile_Reference (R) | |
996ae0b0 RK |
589 | then |
590 | return True; | |
591 | ||
592 | -- Or if they are compile time known and identical | |
593 | ||
594 | elsif Compile_Time_Known_Value (Lf) | |
595 | and then | |
596 | Compile_Time_Known_Value (Rf) | |
597 | and then Expr_Value (Lf) = Expr_Value (Rf) | |
598 | then | |
599 | return True; | |
600 | ||
b49365b2 RD |
601 | -- False if Nkind of the two nodes is different for remaining cases |
602 | ||
603 | elsif Nkind (Lf) /= Nkind (Rf) then | |
604 | return False; | |
605 | ||
606 | -- True if both 'First or 'Last values applying to the same entity | |
607 | -- (first and last don't change even if value does). Note that we | |
608 | -- need this even with the calls to Compare_Fixup, to handle the | |
609 | -- case of unconstrained array attributes where Compare_Fixup | |
610 | -- cannot find useful bounds. | |
996ae0b0 RK |
611 | |
612 | elsif Nkind (Lf) = N_Attribute_Reference | |
996ae0b0 RK |
613 | and then Attribute_Name (Lf) = Attribute_Name (Rf) |
614 | and then (Attribute_Name (Lf) = Name_First | |
615 | or else | |
616 | Attribute_Name (Lf) = Name_Last) | |
b49365b2 RD |
617 | and then Nkind_In (Prefix (Lf), N_Identifier, N_Expanded_Name) |
618 | and then Nkind_In (Prefix (Rf), N_Identifier, N_Expanded_Name) | |
996ae0b0 | 619 | and then Entity (Prefix (Lf)) = Entity (Prefix (Rf)) |
fbf5a39b | 620 | and then Is_Same_Subscript (Expressions (Lf), Expressions (Rf)) |
996ae0b0 RK |
621 | then |
622 | return True; | |
623 | ||
b49365b2 RD |
624 | -- True if the same selected component from the same record |
625 | ||
626 | elsif Nkind (Lf) = N_Selected_Component | |
627 | and then Selector_Name (Lf) = Selector_Name (Rf) | |
628 | and then Is_Same_Value (Prefix (Lf), Prefix (Rf)) | |
629 | then | |
630 | return True; | |
631 | ||
632 | -- True if the same unary operator applied to the same operand | |
633 | ||
634 | elsif Nkind (Lf) in N_Unary_Op | |
635 | and then Is_Same_Value (Right_Opnd (Lf), Right_Opnd (Rf)) | |
636 | then | |
637 | return True; | |
638 | ||
8682d22c | 639 | -- True if the same binary operator applied to the same operands |
b49365b2 RD |
640 | |
641 | elsif Nkind (Lf) in N_Binary_Op | |
642 | and then Is_Same_Value (Left_Opnd (Lf), Left_Opnd (Rf)) | |
643 | and then Is_Same_Value (Right_Opnd (Lf), Right_Opnd (Rf)) | |
644 | then | |
645 | return True; | |
646 | ||
8682d22c | 647 | -- All other cases, we can't tell, so return False |
996ae0b0 RK |
648 | |
649 | else | |
650 | return False; | |
651 | end if; | |
652 | end Is_Same_Value; | |
653 | ||
654 | -- Start of processing for Compile_Time_Compare | |
655 | ||
656 | begin | |
07fc65c4 GB |
657 | -- If either operand could raise constraint error, then we cannot |
658 | -- know the result at compile time (since CE may be raised!) | |
659 | ||
660 | if not (Cannot_Raise_Constraint_Error (L) | |
661 | and then | |
662 | Cannot_Raise_Constraint_Error (R)) | |
663 | then | |
664 | return Unknown; | |
665 | end if; | |
666 | ||
667 | -- Identical operands are most certainly equal | |
668 | ||
996ae0b0 RK |
669 | if L = R then |
670 | return EQ; | |
671 | ||
672 | -- If expressions have no types, then do not attempt to determine | |
673 | -- if they are the same, since something funny is going on. One | |
674 | -- case in which this happens is during generic template analysis, | |
675 | -- when bounds are not fully analyzed. | |
676 | ||
677 | elsif No (Ltyp) or else No (Rtyp) then | |
678 | return Unknown; | |
679 | ||
fbf5a39b AC |
680 | -- We only attempt compile time analysis for scalar values, and |
681 | -- not for packed arrays represented as modular types, where the | |
682 | -- semantics of comparison is quite different. | |
996ae0b0 RK |
683 | |
684 | elsif not Is_Scalar_Type (Ltyp) | |
685 | or else Is_Packed_Array_Type (Ltyp) | |
686 | then | |
687 | return Unknown; | |
688 | ||
689 | -- Case where comparison involves two compile time known values | |
690 | ||
691 | elsif Compile_Time_Known_Value (L) | |
692 | and then Compile_Time_Known_Value (R) | |
693 | then | |
694 | -- For the floating-point case, we have to be a little careful, since | |
695 | -- at compile time we are dealing with universal exact values, but at | |
696 | -- runtime, these will be in non-exact target form. That's why the | |
697 | -- returned results are LE and GE below instead of LT and GT. | |
698 | ||
699 | if Is_Floating_Point_Type (Ltyp) | |
700 | or else | |
701 | Is_Floating_Point_Type (Rtyp) | |
702 | then | |
703 | declare | |
704 | Lo : constant Ureal := Expr_Value_R (L); | |
705 | Hi : constant Ureal := Expr_Value_R (R); | |
706 | ||
707 | begin | |
708 | if Lo < Hi then | |
709 | return LE; | |
710 | elsif Lo = Hi then | |
711 | return EQ; | |
712 | else | |
713 | return GE; | |
714 | end if; | |
715 | end; | |
716 | ||
717 | -- For the integer case we know exactly (note that this includes the | |
718 | -- fixed-point case, where we know the run time integer values now) | |
719 | ||
720 | else | |
721 | declare | |
722 | Lo : constant Uint := Expr_Value (L); | |
723 | Hi : constant Uint := Expr_Value (R); | |
724 | ||
725 | begin | |
726 | if Lo < Hi then | |
727 | return LT; | |
728 | elsif Lo = Hi then | |
729 | return EQ; | |
730 | else | |
731 | return GT; | |
732 | end if; | |
733 | end; | |
734 | end if; | |
735 | ||
736 | -- Cases where at least one operand is not known at compile time | |
737 | ||
738 | else | |
29797f34 RD |
739 | -- Remaining checks apply only for non-generic discrete types |
740 | ||
741 | if not Is_Discrete_Type (Ltyp) | |
742 | or else not Is_Discrete_Type (Rtyp) | |
743 | or else Is_Generic_Type (Ltyp) | |
744 | or else Is_Generic_Type (Rtyp) | |
745 | then | |
746 | return Unknown; | |
747 | end if; | |
748 | ||
1c7717c3 AC |
749 | -- Replace types by base types for the case of entities which are |
750 | -- not known to have valid representations. This takes care of | |
751 | -- properly dealing with invalid representations. | |
752 | ||
c800f862 | 753 | if not Assume_Valid and then not Assume_No_Invalid_Values then |
1c7717c3 AC |
754 | if Is_Entity_Name (L) and then not Is_Known_Valid (Entity (L)) then |
755 | Ltyp := Base_Type (Ltyp); | |
756 | end if; | |
757 | ||
758 | if Is_Entity_Name (R) and then not Is_Known_Valid (Entity (R)) then | |
759 | Rtyp := Base_Type (Rtyp); | |
760 | end if; | |
761 | end if; | |
762 | ||
c800f862 RD |
763 | -- Try range analysis on variables and see if ranges are disjoint |
764 | ||
765 | declare | |
766 | LOK, ROK : Boolean; | |
767 | LLo, LHi : Uint; | |
768 | RLo, RHi : Uint; | |
769 | ||
770 | begin | |
771 | Determine_Range (L, LOK, LLo, LHi, Assume_Valid); | |
772 | Determine_Range (R, ROK, RLo, RHi, Assume_Valid); | |
773 | ||
774 | if LOK and ROK then | |
775 | if LHi < RLo then | |
776 | return LT; | |
777 | ||
778 | elsif RHi < LLo then | |
779 | return GT; | |
780 | ||
781 | elsif LLo = LHi | |
782 | and then RLo = RHi | |
783 | and then LLo = RLo | |
784 | then | |
785 | return EQ; | |
786 | ||
787 | elsif LHi = RLo then | |
788 | return LE; | |
789 | ||
790 | elsif RHi = LLo then | |
791 | return GE; | |
792 | end if; | |
793 | end if; | |
794 | end; | |
795 | ||
996ae0b0 RK |
796 | -- Here is where we check for comparisons against maximum bounds of |
797 | -- types, where we know that no value can be outside the bounds of | |
798 | -- the subtype. Note that this routine is allowed to assume that all | |
799 | -- expressions are within their subtype bounds. Callers wishing to | |
800 | -- deal with possibly invalid values must in any case take special | |
801 | -- steps (e.g. conversions to larger types) to avoid this kind of | |
802 | -- optimization, which is always considered to be valid. We do not | |
803 | -- attempt this optimization with generic types, since the type | |
804 | -- bounds may not be meaningful in this case. | |
805 | ||
29797f34 | 806 | -- We are in danger of an infinite recursion here. It does not seem |
fbf5a39b AC |
807 | -- useful to go more than one level deep, so the parameter Rec is |
808 | -- used to protect ourselves against this infinite recursion. | |
809 | ||
29797f34 RD |
810 | if not Rec then |
811 | ||
fbf5a39b AC |
812 | -- See if we can get a decisive check against one operand and |
813 | -- a bound of the other operand (four possible tests here). | |
814 | ||
1c7717c3 AC |
815 | case Compile_Time_Compare (L, Type_Low_Bound (Rtyp), |
816 | Assume_Valid, Rec => True) is | |
fbf5a39b AC |
817 | when LT => return LT; |
818 | when LE => return LE; | |
819 | when EQ => return LE; | |
820 | when others => null; | |
821 | end case; | |
996ae0b0 | 822 | |
1c7717c3 AC |
823 | case Compile_Time_Compare (L, Type_High_Bound (Rtyp), |
824 | Assume_Valid, Rec => True) is | |
fbf5a39b AC |
825 | when GT => return GT; |
826 | when GE => return GE; | |
827 | when EQ => return GE; | |
828 | when others => null; | |
829 | end case; | |
996ae0b0 | 830 | |
1c7717c3 AC |
831 | case Compile_Time_Compare (Type_Low_Bound (Ltyp), R, |
832 | Assume_Valid, Rec => True) is | |
fbf5a39b AC |
833 | when GT => return GT; |
834 | when GE => return GE; | |
835 | when EQ => return GE; | |
836 | when others => null; | |
837 | end case; | |
996ae0b0 | 838 | |
1c7717c3 AC |
839 | case Compile_Time_Compare (Type_High_Bound (Ltyp), R, |
840 | Assume_Valid, Rec => True) is | |
fbf5a39b AC |
841 | when LT => return LT; |
842 | when LE => return LE; | |
843 | when EQ => return LE; | |
844 | when others => null; | |
845 | end case; | |
996ae0b0 RK |
846 | end if; |
847 | ||
848 | -- Next attempt is to decompose the expressions to extract | |
849 | -- a constant offset resulting from the use of any of the forms: | |
850 | ||
851 | -- expr + literal | |
852 | -- expr - literal | |
853 | -- typ'Succ (expr) | |
854 | -- typ'Pred (expr) | |
855 | ||
856 | -- Then we see if the two expressions are the same value, and if so | |
857 | -- the result is obtained by comparing the offsets. | |
858 | ||
859 | declare | |
860 | Lnode : Node_Id; | |
861 | Loffs : Uint; | |
862 | Rnode : Node_Id; | |
863 | Roffs : Uint; | |
864 | ||
865 | begin | |
866 | Compare_Decompose (L, Lnode, Loffs); | |
867 | Compare_Decompose (R, Rnode, Roffs); | |
868 | ||
869 | if Is_Same_Value (Lnode, Rnode) then | |
870 | if Loffs = Roffs then | |
871 | return EQ; | |
872 | ||
873 | elsif Loffs < Roffs then | |
874 | return LT; | |
875 | ||
876 | else | |
877 | return GT; | |
878 | end if; | |
29797f34 RD |
879 | end if; |
880 | end; | |
881 | ||
882 | -- Next attempt is to see if we have an entity compared with a | |
883 | -- compile time known value, where there is a current value | |
884 | -- conditional for the entity which can tell us the result. | |
885 | ||
886 | declare | |
887 | Var : Node_Id; | |
888 | -- Entity variable (left operand) | |
889 | ||
890 | Val : Uint; | |
891 | -- Value (right operand) | |
892 | ||
893 | Inv : Boolean; | |
894 | -- If False, we have reversed the operands | |
895 | ||
896 | Op : Node_Kind; | |
897 | -- Comparison operator kind from Get_Current_Value_Condition call | |
996ae0b0 | 898 | |
29797f34 RD |
899 | Opn : Node_Id; |
900 | -- Value from Get_Current_Value_Condition call | |
901 | ||
902 | Opv : Uint; | |
903 | -- Value of Opn | |
904 | ||
905 | Result : Compare_Result; | |
906 | -- Known result before inversion | |
907 | ||
908 | begin | |
909 | if Is_Entity_Name (L) | |
910 | and then Compile_Time_Known_Value (R) | |
911 | then | |
912 | Var := L; | |
913 | Val := Expr_Value (R); | |
914 | Inv := False; | |
915 | ||
916 | elsif Is_Entity_Name (R) | |
917 | and then Compile_Time_Known_Value (L) | |
918 | then | |
919 | Var := R; | |
920 | Val := Expr_Value (L); | |
921 | Inv := True; | |
922 | ||
923 | -- That was the last chance at finding a compile time result | |
996ae0b0 RK |
924 | |
925 | else | |
926 | return Unknown; | |
927 | end if; | |
29797f34 RD |
928 | |
929 | Get_Current_Value_Condition (Var, Op, Opn); | |
930 | ||
931 | -- That was the last chance, so if we got nothing return | |
932 | ||
933 | if No (Opn) then | |
934 | return Unknown; | |
935 | end if; | |
936 | ||
937 | Opv := Expr_Value (Opn); | |
938 | ||
939 | -- We got a comparison, so we might have something interesting | |
940 | ||
941 | -- Convert LE to LT and GE to GT, just so we have fewer cases | |
942 | ||
943 | if Op = N_Op_Le then | |
944 | Op := N_Op_Lt; | |
945 | Opv := Opv + 1; | |
946 | elsif Op = N_Op_Ge then | |
947 | Op := N_Op_Gt; | |
948 | Opv := Opv - 1; | |
949 | end if; | |
950 | ||
951 | -- Deal with equality case | |
952 | ||
953 | if Op = N_Op_Eq then | |
954 | if Val = Opv then | |
955 | Result := EQ; | |
956 | elsif Opv < Val then | |
957 | Result := LT; | |
958 | else | |
959 | Result := GT; | |
960 | end if; | |
961 | ||
962 | -- Deal with inequality case | |
963 | ||
964 | elsif Op = N_Op_Ne then | |
965 | if Val = Opv then | |
966 | Result := NE; | |
967 | else | |
968 | return Unknown; | |
969 | end if; | |
970 | ||
971 | -- Deal with greater than case | |
972 | ||
973 | elsif Op = N_Op_Gt then | |
974 | if Opv >= Val then | |
975 | Result := GT; | |
976 | elsif Opv = Val - 1 then | |
977 | Result := GE; | |
978 | else | |
979 | return Unknown; | |
980 | end if; | |
981 | ||
982 | -- Deal with less than case | |
983 | ||
984 | else pragma Assert (Op = N_Op_Lt); | |
985 | if Opv <= Val then | |
986 | Result := LT; | |
987 | elsif Opv = Val + 1 then | |
988 | Result := LE; | |
989 | else | |
990 | return Unknown; | |
991 | end if; | |
992 | end if; | |
993 | ||
994 | -- Deal with inverting result | |
995 | ||
996 | if Inv then | |
997 | case Result is | |
998 | when GT => return LT; | |
999 | when GE => return LE; | |
1000 | when LT => return GT; | |
1001 | when LE => return GE; | |
1002 | when others => return Result; | |
1003 | end case; | |
1004 | end if; | |
1005 | ||
1006 | return Result; | |
996ae0b0 RK |
1007 | end; |
1008 | end if; | |
1009 | end Compile_Time_Compare; | |
1010 | ||
f44fe430 RD |
1011 | ------------------------------- |
1012 | -- Compile_Time_Known_Bounds -- | |
1013 | ------------------------------- | |
1014 | ||
1015 | function Compile_Time_Known_Bounds (T : Entity_Id) return Boolean is | |
1016 | Indx : Node_Id; | |
1017 | Typ : Entity_Id; | |
1018 | ||
1019 | begin | |
1020 | if not Is_Array_Type (T) then | |
1021 | return False; | |
1022 | end if; | |
1023 | ||
1024 | Indx := First_Index (T); | |
1025 | while Present (Indx) loop | |
1026 | Typ := Underlying_Type (Etype (Indx)); | |
1027 | if not Compile_Time_Known_Value (Type_Low_Bound (Typ)) then | |
1028 | return False; | |
1029 | elsif not Compile_Time_Known_Value (Type_High_Bound (Typ)) then | |
1030 | return False; | |
1031 | else | |
1032 | Next_Index (Indx); | |
1033 | end if; | |
1034 | end loop; | |
1035 | ||
1036 | return True; | |
1037 | end Compile_Time_Known_Bounds; | |
1038 | ||
996ae0b0 RK |
1039 | ------------------------------ |
1040 | -- Compile_Time_Known_Value -- | |
1041 | ------------------------------ | |
1042 | ||
1043 | function Compile_Time_Known_Value (Op : Node_Id) return Boolean is | |
07fc65c4 GB |
1044 | K : constant Node_Kind := Nkind (Op); |
1045 | CV_Ent : CV_Entry renames CV_Cache (Nat (Op) mod CV_Cache_Size); | |
996ae0b0 RK |
1046 | |
1047 | begin | |
1048 | -- Never known at compile time if bad type or raises constraint error | |
1049 | -- or empty (latter case occurs only as a result of a previous error) | |
1050 | ||
1051 | if No (Op) | |
1052 | or else Op = Error | |
1053 | or else Etype (Op) = Any_Type | |
1054 | or else Raises_Constraint_Error (Op) | |
1055 | then | |
1056 | return False; | |
1057 | end if; | |
1058 | ||
597d7158 GD |
1059 | -- If this is not a static expression or a null literal, and we are in |
1060 | -- configurable run-time mode, then we consider it not known at compile | |
1061 | -- time. This avoids anomalies where whether something is allowed with a | |
1062 | -- given configurable run-time library depends on how good the compiler | |
1063 | -- is at optimizing and knowing that things are constant when they are | |
1064 | -- nonstatic. | |
1065 | ||
1066 | if Configurable_Run_Time_Mode | |
1067 | and then K /= N_Null | |
1068 | and then not Is_Static_Expression (Op) | |
1069 | then | |
fbf5a39b AC |
1070 | return False; |
1071 | end if; | |
1072 | ||
996ae0b0 RK |
1073 | -- If we have an entity name, then see if it is the name of a constant |
1074 | -- and if so, test the corresponding constant value, or the name of | |
1075 | -- an enumeration literal, which is always a constant. | |
1076 | ||
1077 | if Present (Etype (Op)) and then Is_Entity_Name (Op) then | |
1078 | declare | |
1079 | E : constant Entity_Id := Entity (Op); | |
1080 | V : Node_Id; | |
1081 | ||
1082 | begin | |
1083 | -- Never known at compile time if it is a packed array value. | |
1084 | -- We might want to try to evaluate these at compile time one | |
1085 | -- day, but we do not make that attempt now. | |
1086 | ||
1087 | if Is_Packed_Array_Type (Etype (Op)) then | |
1088 | return False; | |
1089 | end if; | |
1090 | ||
1091 | if Ekind (E) = E_Enumeration_Literal then | |
1092 | return True; | |
1093 | ||
07fc65c4 | 1094 | elsif Ekind (E) = E_Constant then |
996ae0b0 RK |
1095 | V := Constant_Value (E); |
1096 | return Present (V) and then Compile_Time_Known_Value (V); | |
1097 | end if; | |
1098 | end; | |
1099 | ||
1100 | -- We have a value, see if it is compile time known | |
1101 | ||
1102 | else | |
07fc65c4 | 1103 | -- Integer literals are worth storing in the cache |
996ae0b0 | 1104 | |
07fc65c4 GB |
1105 | if K = N_Integer_Literal then |
1106 | CV_Ent.N := Op; | |
1107 | CV_Ent.V := Intval (Op); | |
1108 | return True; | |
1109 | ||
1110 | -- Other literals and NULL are known at compile time | |
1111 | ||
1112 | elsif | |
996ae0b0 RK |
1113 | K = N_Character_Literal |
1114 | or else | |
1115 | K = N_Real_Literal | |
1116 | or else | |
1117 | K = N_String_Literal | |
1118 | or else | |
1119 | K = N_Null | |
1120 | then | |
1121 | return True; | |
1122 | ||
1123 | -- Any reference to Null_Parameter is known at compile time. No | |
1124 | -- other attribute references (that have not already been folded) | |
1125 | -- are known at compile time. | |
1126 | ||
1127 | elsif K = N_Attribute_Reference then | |
1128 | return Attribute_Name (Op) = Name_Null_Parameter; | |
07fc65c4 | 1129 | end if; |
996ae0b0 | 1130 | end if; |
07fc65c4 GB |
1131 | |
1132 | -- If we fall through, not known at compile time | |
1133 | ||
1134 | return False; | |
1135 | ||
1136 | -- If we get an exception while trying to do this test, then some error | |
1137 | -- has occurred, and we simply say that the value is not known after all | |
1138 | ||
1139 | exception | |
1140 | when others => | |
1141 | return False; | |
996ae0b0 RK |
1142 | end Compile_Time_Known_Value; |
1143 | ||
1144 | -------------------------------------- | |
1145 | -- Compile_Time_Known_Value_Or_Aggr -- | |
1146 | -------------------------------------- | |
1147 | ||
1148 | function Compile_Time_Known_Value_Or_Aggr (Op : Node_Id) return Boolean is | |
1149 | begin | |
1150 | -- If we have an entity name, then see if it is the name of a constant | |
1151 | -- and if so, test the corresponding constant value, or the name of | |
1152 | -- an enumeration literal, which is always a constant. | |
1153 | ||
1154 | if Is_Entity_Name (Op) then | |
1155 | declare | |
1156 | E : constant Entity_Id := Entity (Op); | |
1157 | V : Node_Id; | |
1158 | ||
1159 | begin | |
1160 | if Ekind (E) = E_Enumeration_Literal then | |
1161 | return True; | |
1162 | ||
1163 | elsif Ekind (E) /= E_Constant then | |
1164 | return False; | |
1165 | ||
1166 | else | |
1167 | V := Constant_Value (E); | |
1168 | return Present (V) | |
1169 | and then Compile_Time_Known_Value_Or_Aggr (V); | |
1170 | end if; | |
1171 | end; | |
1172 | ||
1173 | -- We have a value, see if it is compile time known | |
1174 | ||
1175 | else | |
1176 | if Compile_Time_Known_Value (Op) then | |
1177 | return True; | |
1178 | ||
1179 | elsif Nkind (Op) = N_Aggregate then | |
1180 | ||
1181 | if Present (Expressions (Op)) then | |
1182 | declare | |
1183 | Expr : Node_Id; | |
1184 | ||
1185 | begin | |
1186 | Expr := First (Expressions (Op)); | |
1187 | while Present (Expr) loop | |
1188 | if not Compile_Time_Known_Value_Or_Aggr (Expr) then | |
1189 | return False; | |
1190 | end if; | |
1191 | ||
1192 | Next (Expr); | |
1193 | end loop; | |
1194 | end; | |
1195 | end if; | |
1196 | ||
1197 | if Present (Component_Associations (Op)) then | |
1198 | declare | |
1199 | Cass : Node_Id; | |
1200 | ||
1201 | begin | |
1202 | Cass := First (Component_Associations (Op)); | |
1203 | while Present (Cass) loop | |
1204 | if not | |
1205 | Compile_Time_Known_Value_Or_Aggr (Expression (Cass)) | |
1206 | then | |
1207 | return False; | |
1208 | end if; | |
1209 | ||
1210 | Next (Cass); | |
1211 | end loop; | |
1212 | end; | |
1213 | end if; | |
1214 | ||
1215 | return True; | |
1216 | ||
1217 | -- All other types of values are not known at compile time | |
1218 | ||
1219 | else | |
1220 | return False; | |
1221 | end if; | |
1222 | ||
1223 | end if; | |
1224 | end Compile_Time_Known_Value_Or_Aggr; | |
1225 | ||
1226 | ----------------- | |
1227 | -- Eval_Actual -- | |
1228 | ----------------- | |
1229 | ||
1230 | -- This is only called for actuals of functions that are not predefined | |
1231 | -- operators (which have already been rewritten as operators at this | |
1232 | -- stage), so the call can never be folded, and all that needs doing for | |
1233 | -- the actual is to do the check for a non-static context. | |
1234 | ||
1235 | procedure Eval_Actual (N : Node_Id) is | |
1236 | begin | |
1237 | Check_Non_Static_Context (N); | |
1238 | end Eval_Actual; | |
1239 | ||
1240 | -------------------- | |
1241 | -- Eval_Allocator -- | |
1242 | -------------------- | |
1243 | ||
1244 | -- Allocators are never static, so all we have to do is to do the | |
1245 | -- check for a non-static context if an expression is present. | |
1246 | ||
1247 | procedure Eval_Allocator (N : Node_Id) is | |
1248 | Expr : constant Node_Id := Expression (N); | |
1249 | ||
1250 | begin | |
1251 | if Nkind (Expr) = N_Qualified_Expression then | |
1252 | Check_Non_Static_Context (Expression (Expr)); | |
1253 | end if; | |
1254 | end Eval_Allocator; | |
1255 | ||
1256 | ------------------------ | |
1257 | -- Eval_Arithmetic_Op -- | |
1258 | ------------------------ | |
1259 | ||
1260 | -- Arithmetic operations are static functions, so the result is static | |
1261 | -- if both operands are static (RM 4.9(7), 4.9(20)). | |
1262 | ||
1263 | procedure Eval_Arithmetic_Op (N : Node_Id) is | |
1264 | Left : constant Node_Id := Left_Opnd (N); | |
1265 | Right : constant Node_Id := Right_Opnd (N); | |
1266 | Ltype : constant Entity_Id := Etype (Left); | |
1267 | Rtype : constant Entity_Id := Etype (Right); | |
1268 | Stat : Boolean; | |
1269 | Fold : Boolean; | |
1270 | ||
1271 | begin | |
1272 | -- If not foldable we are done | |
1273 | ||
1274 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
1275 | ||
1276 | if not Fold then | |
1277 | return; | |
1278 | end if; | |
1279 | ||
1280 | -- Fold for cases where both operands are of integer type | |
1281 | ||
1282 | if Is_Integer_Type (Ltype) and then Is_Integer_Type (Rtype) then | |
1283 | declare | |
1284 | Left_Int : constant Uint := Expr_Value (Left); | |
1285 | Right_Int : constant Uint := Expr_Value (Right); | |
1286 | Result : Uint; | |
1287 | ||
1288 | begin | |
1289 | case Nkind (N) is | |
1290 | ||
1291 | when N_Op_Add => | |
1292 | Result := Left_Int + Right_Int; | |
1293 | ||
1294 | when N_Op_Subtract => | |
1295 | Result := Left_Int - Right_Int; | |
1296 | ||
1297 | when N_Op_Multiply => | |
1298 | if OK_Bits | |
1299 | (N, UI_From_Int | |
1300 | (Num_Bits (Left_Int) + Num_Bits (Right_Int))) | |
1301 | then | |
1302 | Result := Left_Int * Right_Int; | |
1303 | else | |
1304 | Result := Left_Int; | |
1305 | end if; | |
1306 | ||
1307 | when N_Op_Divide => | |
1308 | ||
1309 | -- The exception Constraint_Error is raised by integer | |
1310 | -- division, rem and mod if the right operand is zero. | |
1311 | ||
1312 | if Right_Int = 0 then | |
1313 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
1314 | (N, "division by zero", |
1315 | CE_Divide_By_Zero, | |
1316 | Warn => not Stat); | |
996ae0b0 | 1317 | return; |
fbf5a39b | 1318 | |
996ae0b0 RK |
1319 | else |
1320 | Result := Left_Int / Right_Int; | |
1321 | end if; | |
1322 | ||
1323 | when N_Op_Mod => | |
1324 | ||
1325 | -- The exception Constraint_Error is raised by integer | |
1326 | -- division, rem and mod if the right operand is zero. | |
1327 | ||
1328 | if Right_Int = 0 then | |
1329 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
1330 | (N, "mod with zero divisor", |
1331 | CE_Divide_By_Zero, | |
1332 | Warn => not Stat); | |
996ae0b0 RK |
1333 | return; |
1334 | else | |
1335 | Result := Left_Int mod Right_Int; | |
1336 | end if; | |
1337 | ||
1338 | when N_Op_Rem => | |
1339 | ||
1340 | -- The exception Constraint_Error is raised by integer | |
1341 | -- division, rem and mod if the right operand is zero. | |
1342 | ||
1343 | if Right_Int = 0 then | |
1344 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
1345 | (N, "rem with zero divisor", |
1346 | CE_Divide_By_Zero, | |
1347 | Warn => not Stat); | |
996ae0b0 | 1348 | return; |
fbf5a39b | 1349 | |
996ae0b0 RK |
1350 | else |
1351 | Result := Left_Int rem Right_Int; | |
1352 | end if; | |
1353 | ||
1354 | when others => | |
1355 | raise Program_Error; | |
1356 | end case; | |
1357 | ||
1358 | -- Adjust the result by the modulus if the type is a modular type | |
1359 | ||
1360 | if Is_Modular_Integer_Type (Ltype) then | |
1361 | Result := Result mod Modulus (Ltype); | |
82c80734 RD |
1362 | |
1363 | -- For a signed integer type, check non-static overflow | |
1364 | ||
1365 | elsif (not Stat) and then Is_Signed_Integer_Type (Ltype) then | |
1366 | declare | |
1367 | BT : constant Entity_Id := Base_Type (Ltype); | |
1368 | Lo : constant Uint := Expr_Value (Type_Low_Bound (BT)); | |
1369 | Hi : constant Uint := Expr_Value (Type_High_Bound (BT)); | |
1370 | begin | |
1371 | if Result < Lo or else Result > Hi then | |
1372 | Apply_Compile_Time_Constraint_Error | |
1373 | (N, "value not in range of }?", | |
1374 | CE_Overflow_Check_Failed, | |
1375 | Ent => BT); | |
1376 | return; | |
1377 | end if; | |
1378 | end; | |
996ae0b0 RK |
1379 | end if; |
1380 | ||
82c80734 RD |
1381 | -- If we get here we can fold the result |
1382 | ||
fbf5a39b | 1383 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
1384 | end; |
1385 | ||
1386 | -- Cases where at least one operand is a real. We handle the cases | |
1387 | -- of both reals, or mixed/real integer cases (the latter happen | |
1388 | -- only for divide and multiply, and the result is always real). | |
1389 | ||
1390 | elsif Is_Real_Type (Ltype) or else Is_Real_Type (Rtype) then | |
1391 | declare | |
1392 | Left_Real : Ureal; | |
1393 | Right_Real : Ureal; | |
1394 | Result : Ureal; | |
1395 | ||
1396 | begin | |
1397 | if Is_Real_Type (Ltype) then | |
1398 | Left_Real := Expr_Value_R (Left); | |
1399 | else | |
1400 | Left_Real := UR_From_Uint (Expr_Value (Left)); | |
1401 | end if; | |
1402 | ||
1403 | if Is_Real_Type (Rtype) then | |
1404 | Right_Real := Expr_Value_R (Right); | |
1405 | else | |
1406 | Right_Real := UR_From_Uint (Expr_Value (Right)); | |
1407 | end if; | |
1408 | ||
1409 | if Nkind (N) = N_Op_Add then | |
1410 | Result := Left_Real + Right_Real; | |
1411 | ||
1412 | elsif Nkind (N) = N_Op_Subtract then | |
1413 | Result := Left_Real - Right_Real; | |
1414 | ||
1415 | elsif Nkind (N) = N_Op_Multiply then | |
1416 | Result := Left_Real * Right_Real; | |
1417 | ||
1418 | else pragma Assert (Nkind (N) = N_Op_Divide); | |
1419 | if UR_Is_Zero (Right_Real) then | |
1420 | Apply_Compile_Time_Constraint_Error | |
07fc65c4 | 1421 | (N, "division by zero", CE_Divide_By_Zero); |
996ae0b0 RK |
1422 | return; |
1423 | end if; | |
1424 | ||
1425 | Result := Left_Real / Right_Real; | |
1426 | end if; | |
1427 | ||
fbf5a39b | 1428 | Fold_Ureal (N, Result, Stat); |
996ae0b0 RK |
1429 | end; |
1430 | end if; | |
996ae0b0 RK |
1431 | end Eval_Arithmetic_Op; |
1432 | ||
1433 | ---------------------------- | |
1434 | -- Eval_Character_Literal -- | |
1435 | ---------------------------- | |
1436 | ||
1437 | -- Nothing to be done! | |
1438 | ||
1439 | procedure Eval_Character_Literal (N : Node_Id) is | |
07fc65c4 | 1440 | pragma Warnings (Off, N); |
996ae0b0 RK |
1441 | begin |
1442 | null; | |
1443 | end Eval_Character_Literal; | |
1444 | ||
c01a9391 AC |
1445 | --------------- |
1446 | -- Eval_Call -- | |
1447 | --------------- | |
1448 | ||
1449 | -- Static function calls are either calls to predefined operators | |
1450 | -- with static arguments, or calls to functions that rename a literal. | |
1451 | -- Only the latter case is handled here, predefined operators are | |
1452 | -- constant-folded elsewhere. | |
29797f34 | 1453 | |
c01a9391 AC |
1454 | -- If the function is itself inherited (see 7423-001) the literal of |
1455 | -- the parent type must be explicitly converted to the return type | |
1456 | -- of the function. | |
1457 | ||
1458 | procedure Eval_Call (N : Node_Id) is | |
1459 | Loc : constant Source_Ptr := Sloc (N); | |
1460 | Typ : constant Entity_Id := Etype (N); | |
1461 | Lit : Entity_Id; | |
1462 | ||
1463 | begin | |
1464 | if Nkind (N) = N_Function_Call | |
1465 | and then No (Parameter_Associations (N)) | |
1466 | and then Is_Entity_Name (Name (N)) | |
1467 | and then Present (Alias (Entity (Name (N)))) | |
1468 | and then Is_Enumeration_Type (Base_Type (Typ)) | |
1469 | then | |
1470 | Lit := Alias (Entity (Name (N))); | |
c01a9391 AC |
1471 | while Present (Alias (Lit)) loop |
1472 | Lit := Alias (Lit); | |
1473 | end loop; | |
1474 | ||
1475 | if Ekind (Lit) = E_Enumeration_Literal then | |
1476 | if Base_Type (Etype (Lit)) /= Base_Type (Typ) then | |
1477 | Rewrite | |
1478 | (N, Convert_To (Typ, New_Occurrence_Of (Lit, Loc))); | |
1479 | else | |
1480 | Rewrite (N, New_Occurrence_Of (Lit, Loc)); | |
1481 | end if; | |
1482 | ||
1483 | Resolve (N, Typ); | |
1484 | end if; | |
1485 | end if; | |
1486 | end Eval_Call; | |
1487 | ||
996ae0b0 RK |
1488 | ------------------------ |
1489 | -- Eval_Concatenation -- | |
1490 | ------------------------ | |
1491 | ||
3996951a TQ |
1492 | -- Concatenation is a static function, so the result is static if both |
1493 | -- operands are static (RM 4.9(7), 4.9(21)). | |
996ae0b0 RK |
1494 | |
1495 | procedure Eval_Concatenation (N : Node_Id) is | |
f91b40db GB |
1496 | Left : constant Node_Id := Left_Opnd (N); |
1497 | Right : constant Node_Id := Right_Opnd (N); | |
1498 | C_Typ : constant Entity_Id := Root_Type (Component_Type (Etype (N))); | |
996ae0b0 RK |
1499 | Stat : Boolean; |
1500 | Fold : Boolean; | |
996ae0b0 RK |
1501 | |
1502 | begin | |
3996951a TQ |
1503 | -- Concatenation is never static in Ada 83, so if Ada 83 check operand |
1504 | -- non-static context. | |
996ae0b0 | 1505 | |
0ab80019 | 1506 | if Ada_Version = Ada_83 |
996ae0b0 RK |
1507 | and then Comes_From_Source (N) |
1508 | then | |
1509 | Check_Non_Static_Context (Left); | |
1510 | Check_Non_Static_Context (Right); | |
1511 | return; | |
1512 | end if; | |
1513 | ||
1514 | -- If not foldable we are done. In principle concatenation that yields | |
1515 | -- any string type is static (i.e. an array type of character types). | |
1516 | -- However, character types can include enumeration literals, and | |
1517 | -- concatenation in that case cannot be described by a literal, so we | |
1518 | -- only consider the operation static if the result is an array of | |
1519 | -- (a descendant of) a predefined character type. | |
1520 | ||
1521 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
1522 | ||
3996951a | 1523 | if not (Is_Standard_Character_Type (C_Typ) and then Fold) then |
996ae0b0 RK |
1524 | Set_Is_Static_Expression (N, False); |
1525 | return; | |
1526 | end if; | |
1527 | ||
82c80734 | 1528 | -- Compile time string concatenation |
996ae0b0 | 1529 | |
3996951a TQ |
1530 | -- ??? Note that operands that are aggregates can be marked as static, |
1531 | -- so we should attempt at a later stage to fold concatenations with | |
1532 | -- such aggregates. | |
996ae0b0 RK |
1533 | |
1534 | declare | |
b54ddf5a BD |
1535 | Left_Str : constant Node_Id := Get_String_Val (Left); |
1536 | Left_Len : Nat; | |
1537 | Right_Str : constant Node_Id := Get_String_Val (Right); | |
1538 | Folded_Val : String_Id; | |
996ae0b0 RK |
1539 | |
1540 | begin | |
1541 | -- Establish new string literal, and store left operand. We make | |
1542 | -- sure to use the special Start_String that takes an operand if | |
1543 | -- the left operand is a string literal. Since this is optimized | |
1544 | -- in the case where that is the most recently created string | |
1545 | -- literal, we ensure efficient time/space behavior for the | |
1546 | -- case of a concatenation of a series of string literals. | |
1547 | ||
1548 | if Nkind (Left_Str) = N_String_Literal then | |
f91b40db | 1549 | Left_Len := String_Length (Strval (Left_Str)); |
b54ddf5a BD |
1550 | |
1551 | -- If the left operand is the empty string, and the right operand | |
1552 | -- is a string literal (the case of "" & "..."), the result is the | |
1553 | -- value of the right operand. This optimization is important when | |
1554 | -- Is_Folded_In_Parser, to avoid copying an enormous right | |
1555 | -- operand. | |
1556 | ||
1557 | if Left_Len = 0 and then Nkind (Right_Str) = N_String_Literal then | |
1558 | Folded_Val := Strval (Right_Str); | |
1559 | else | |
1560 | Start_String (Strval (Left_Str)); | |
1561 | end if; | |
1562 | ||
996ae0b0 RK |
1563 | else |
1564 | Start_String; | |
82c80734 | 1565 | Store_String_Char (UI_To_CC (Char_Literal_Value (Left_Str))); |
f91b40db | 1566 | Left_Len := 1; |
996ae0b0 RK |
1567 | end if; |
1568 | ||
b54ddf5a BD |
1569 | -- Now append the characters of the right operand, unless we |
1570 | -- optimized the "" & "..." case above. | |
996ae0b0 RK |
1571 | |
1572 | if Nkind (Right_Str) = N_String_Literal then | |
b54ddf5a BD |
1573 | if Left_Len /= 0 then |
1574 | Store_String_Chars (Strval (Right_Str)); | |
1575 | Folded_Val := End_String; | |
1576 | end if; | |
996ae0b0 | 1577 | else |
82c80734 | 1578 | Store_String_Char (UI_To_CC (Char_Literal_Value (Right_Str))); |
b54ddf5a | 1579 | Folded_Val := End_String; |
996ae0b0 RK |
1580 | end if; |
1581 | ||
1582 | Set_Is_Static_Expression (N, Stat); | |
1583 | ||
1584 | if Stat then | |
f91b40db GB |
1585 | |
1586 | -- If left operand is the empty string, the result is the | |
1587 | -- right operand, including its bounds if anomalous. | |
1588 | ||
1589 | if Left_Len = 0 | |
1590 | and then Is_Array_Type (Etype (Right)) | |
1591 | and then Etype (Right) /= Any_String | |
1592 | then | |
1593 | Set_Etype (N, Etype (Right)); | |
1594 | end if; | |
1595 | ||
b54ddf5a | 1596 | Fold_Str (N, Folded_Val, Static => True); |
996ae0b0 RK |
1597 | end if; |
1598 | end; | |
1599 | end Eval_Concatenation; | |
1600 | ||
1601 | --------------------------------- | |
1602 | -- Eval_Conditional_Expression -- | |
1603 | --------------------------------- | |
1604 | ||
1605 | -- This GNAT internal construct can never be statically folded, so the | |
1606 | -- only required processing is to do the check for non-static context | |
1607 | -- for the two expression operands. | |
1608 | ||
1609 | procedure Eval_Conditional_Expression (N : Node_Id) is | |
1610 | Condition : constant Node_Id := First (Expressions (N)); | |
1611 | Then_Expr : constant Node_Id := Next (Condition); | |
1612 | Else_Expr : constant Node_Id := Next (Then_Expr); | |
1613 | ||
1614 | begin | |
1615 | Check_Non_Static_Context (Then_Expr); | |
1616 | Check_Non_Static_Context (Else_Expr); | |
1617 | end Eval_Conditional_Expression; | |
1618 | ||
1619 | ---------------------- | |
1620 | -- Eval_Entity_Name -- | |
1621 | ---------------------- | |
1622 | ||
1623 | -- This procedure is used for identifiers and expanded names other than | |
1624 | -- named numbers (see Eval_Named_Integer, Eval_Named_Real. These are | |
1625 | -- static if they denote a static constant (RM 4.9(6)) or if the name | |
1626 | -- denotes an enumeration literal (RM 4.9(22)). | |
1627 | ||
1628 | procedure Eval_Entity_Name (N : Node_Id) is | |
1629 | Def_Id : constant Entity_Id := Entity (N); | |
1630 | Val : Node_Id; | |
1631 | ||
1632 | begin | |
1633 | -- Enumeration literals are always considered to be constants | |
1634 | -- and cannot raise constraint error (RM 4.9(22)). | |
1635 | ||
1636 | if Ekind (Def_Id) = E_Enumeration_Literal then | |
1637 | Set_Is_Static_Expression (N); | |
1638 | return; | |
1639 | ||
1640 | -- A name is static if it denotes a static constant (RM 4.9(5)), and | |
1641 | -- we also copy Raise_Constraint_Error. Notice that even if non-static, | |
1642 | -- it does not violate 10.2.1(8) here, since this is not a variable. | |
1643 | ||
1644 | elsif Ekind (Def_Id) = E_Constant then | |
1645 | ||
1646 | -- Deferred constants must always be treated as nonstatic | |
1647 | -- outside the scope of their full view. | |
1648 | ||
1649 | if Present (Full_View (Def_Id)) | |
1650 | and then not In_Open_Scopes (Scope (Def_Id)) | |
1651 | then | |
1652 | Val := Empty; | |
1653 | else | |
1654 | Val := Constant_Value (Def_Id); | |
1655 | end if; | |
1656 | ||
1657 | if Present (Val) then | |
1658 | Set_Is_Static_Expression | |
1659 | (N, Is_Static_Expression (Val) | |
1660 | and then Is_Static_Subtype (Etype (Def_Id))); | |
1661 | Set_Raises_Constraint_Error (N, Raises_Constraint_Error (Val)); | |
1662 | ||
1663 | if not Is_Static_Expression (N) | |
1664 | and then not Is_Generic_Type (Etype (N)) | |
1665 | then | |
1666 | Validate_Static_Object_Name (N); | |
1667 | end if; | |
1668 | ||
1669 | return; | |
1670 | end if; | |
1671 | end if; | |
1672 | ||
82c80734 | 1673 | -- Fall through if the name is not static |
996ae0b0 RK |
1674 | |
1675 | Validate_Static_Object_Name (N); | |
1676 | end Eval_Entity_Name; | |
1677 | ||
1678 | ---------------------------- | |
1679 | -- Eval_Indexed_Component -- | |
1680 | ---------------------------- | |
1681 | ||
8cbb664e MG |
1682 | -- Indexed components are never static, so we need to perform the check |
1683 | -- for non-static context on the index values. Then, we check if the | |
1684 | -- value can be obtained at compile time, even though it is non-static. | |
996ae0b0 RK |
1685 | |
1686 | procedure Eval_Indexed_Component (N : Node_Id) is | |
1687 | Expr : Node_Id; | |
1688 | ||
1689 | begin | |
fbf5a39b AC |
1690 | -- Check for non-static context on index values |
1691 | ||
996ae0b0 RK |
1692 | Expr := First (Expressions (N)); |
1693 | while Present (Expr) loop | |
1694 | Check_Non_Static_Context (Expr); | |
1695 | Next (Expr); | |
1696 | end loop; | |
1697 | ||
fbf5a39b AC |
1698 | -- If the indexed component appears in an object renaming declaration |
1699 | -- then we do not want to try to evaluate it, since in this case we | |
1700 | -- need the identity of the array element. | |
1701 | ||
1702 | if Nkind (Parent (N)) = N_Object_Renaming_Declaration then | |
1703 | return; | |
1704 | ||
1705 | -- Similarly if the indexed component appears as the prefix of an | |
1706 | -- attribute we don't want to evaluate it, because at least for | |
1707 | -- some cases of attributes we need the identify (e.g. Access, Size) | |
1708 | ||
1709 | elsif Nkind (Parent (N)) = N_Attribute_Reference then | |
1710 | return; | |
1711 | end if; | |
1712 | ||
1713 | -- Note: there are other cases, such as the left side of an assignment, | |
1714 | -- or an OUT parameter for a call, where the replacement results in the | |
1715 | -- illegal use of a constant, But these cases are illegal in the first | |
1716 | -- place, so the replacement, though silly, is harmless. | |
1717 | ||
1718 | -- Now see if this is a constant array reference | |
8cbb664e MG |
1719 | |
1720 | if List_Length (Expressions (N)) = 1 | |
1721 | and then Is_Entity_Name (Prefix (N)) | |
1722 | and then Ekind (Entity (Prefix (N))) = E_Constant | |
1723 | and then Present (Constant_Value (Entity (Prefix (N)))) | |
1724 | then | |
1725 | declare | |
1726 | Loc : constant Source_Ptr := Sloc (N); | |
1727 | Arr : constant Node_Id := Constant_Value (Entity (Prefix (N))); | |
1728 | Sub : constant Node_Id := First (Expressions (N)); | |
1729 | ||
1730 | Atyp : Entity_Id; | |
1731 | -- Type of array | |
1732 | ||
1733 | Lin : Nat; | |
1734 | -- Linear one's origin subscript value for array reference | |
1735 | ||
1736 | Lbd : Node_Id; | |
1737 | -- Lower bound of the first array index | |
1738 | ||
1739 | Elm : Node_Id; | |
1740 | -- Value from constant array | |
1741 | ||
1742 | begin | |
1743 | Atyp := Etype (Arr); | |
1744 | ||
1745 | if Is_Access_Type (Atyp) then | |
1746 | Atyp := Designated_Type (Atyp); | |
1747 | end if; | |
1748 | ||
1749 | -- If we have an array type (we should have but perhaps there | |
1750 | -- are error cases where this is not the case), then see if we | |
1751 | -- can do a constant evaluation of the array reference. | |
1752 | ||
1753 | if Is_Array_Type (Atyp) then | |
1754 | if Ekind (Atyp) = E_String_Literal_Subtype then | |
1755 | Lbd := String_Literal_Low_Bound (Atyp); | |
1756 | else | |
1757 | Lbd := Type_Low_Bound (Etype (First_Index (Atyp))); | |
1758 | end if; | |
1759 | ||
1760 | if Compile_Time_Known_Value (Sub) | |
1761 | and then Nkind (Arr) = N_Aggregate | |
1762 | and then Compile_Time_Known_Value (Lbd) | |
1763 | and then Is_Discrete_Type (Component_Type (Atyp)) | |
1764 | then | |
1765 | Lin := UI_To_Int (Expr_Value (Sub) - Expr_Value (Lbd)) + 1; | |
1766 | ||
1767 | if List_Length (Expressions (Arr)) >= Lin then | |
1768 | Elm := Pick (Expressions (Arr), Lin); | |
1769 | ||
1770 | -- If the resulting expression is compile time known, | |
1771 | -- then we can rewrite the indexed component with this | |
1772 | -- value, being sure to mark the result as non-static. | |
1773 | -- We also reset the Sloc, in case this generates an | |
1774 | -- error later on (e.g. 136'Access). | |
1775 | ||
1776 | if Compile_Time_Known_Value (Elm) then | |
1777 | Rewrite (N, Duplicate_Subexpr_No_Checks (Elm)); | |
1778 | Set_Is_Static_Expression (N, False); | |
1779 | Set_Sloc (N, Loc); | |
1780 | end if; | |
1781 | end if; | |
1782 | end if; | |
1783 | end if; | |
1784 | end; | |
1785 | end if; | |
996ae0b0 RK |
1786 | end Eval_Indexed_Component; |
1787 | ||
1788 | -------------------------- | |
1789 | -- Eval_Integer_Literal -- | |
1790 | -------------------------- | |
1791 | ||
1792 | -- Numeric literals are static (RM 4.9(1)), and have already been marked | |
1793 | -- as static by the analyzer. The reason we did it that early is to allow | |
1794 | -- the possibility of turning off the Is_Static_Expression flag after | |
1795 | -- analysis, but before resolution, when integer literals are generated | |
1796 | -- in the expander that do not correspond to static expressions. | |
1797 | ||
1798 | procedure Eval_Integer_Literal (N : Node_Id) is | |
1799 | T : constant Entity_Id := Etype (N); | |
1800 | ||
5d09245e AC |
1801 | function In_Any_Integer_Context return Boolean; |
1802 | -- If the literal is resolved with a specific type in a context | |
1803 | -- where the expected type is Any_Integer, there are no range checks | |
1804 | -- on the literal. By the time the literal is evaluated, it carries | |
1805 | -- the type imposed by the enclosing expression, and we must recover | |
1806 | -- the context to determine that Any_Integer is meant. | |
1807 | ||
1808 | ---------------------------- | |
1809 | -- To_Any_Integer_Context -- | |
1810 | ---------------------------- | |
1811 | ||
1812 | function In_Any_Integer_Context return Boolean is | |
1813 | Par : constant Node_Id := Parent (N); | |
1814 | K : constant Node_Kind := Nkind (Par); | |
1815 | ||
1816 | begin | |
1817 | -- Any_Integer also appears in digits specifications for real types, | |
1818 | -- but those have bounds smaller that those of any integer base | |
1819 | -- type, so we can safely ignore these cases. | |
1820 | ||
1821 | return K = N_Number_Declaration | |
1822 | or else K = N_Attribute_Reference | |
1823 | or else K = N_Attribute_Definition_Clause | |
1824 | or else K = N_Modular_Type_Definition | |
1825 | or else K = N_Signed_Integer_Type_Definition; | |
1826 | end In_Any_Integer_Context; | |
1827 | ||
1828 | -- Start of processing for Eval_Integer_Literal | |
1829 | ||
996ae0b0 | 1830 | begin |
5d09245e | 1831 | |
996ae0b0 RK |
1832 | -- If the literal appears in a non-expression context, then it is |
1833 | -- certainly appearing in a non-static context, so check it. This | |
1834 | -- is actually a redundant check, since Check_Non_Static_Context | |
1835 | -- would check it, but it seems worth while avoiding the call. | |
1836 | ||
5d09245e AC |
1837 | if Nkind (Parent (N)) not in N_Subexpr |
1838 | and then not In_Any_Integer_Context | |
1839 | then | |
996ae0b0 RK |
1840 | Check_Non_Static_Context (N); |
1841 | end if; | |
1842 | ||
1843 | -- Modular integer literals must be in their base range | |
1844 | ||
1845 | if Is_Modular_Integer_Type (T) | |
c800f862 | 1846 | and then Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) |
996ae0b0 RK |
1847 | then |
1848 | Out_Of_Range (N); | |
1849 | end if; | |
1850 | end Eval_Integer_Literal; | |
1851 | ||
1852 | --------------------- | |
1853 | -- Eval_Logical_Op -- | |
1854 | --------------------- | |
1855 | ||
1856 | -- Logical operations are static functions, so the result is potentially | |
1857 | -- static if both operands are potentially static (RM 4.9(7), 4.9(20)). | |
1858 | ||
1859 | procedure Eval_Logical_Op (N : Node_Id) is | |
1860 | Left : constant Node_Id := Left_Opnd (N); | |
1861 | Right : constant Node_Id := Right_Opnd (N); | |
1862 | Stat : Boolean; | |
1863 | Fold : Boolean; | |
1864 | ||
1865 | begin | |
1866 | -- If not foldable we are done | |
1867 | ||
1868 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
1869 | ||
1870 | if not Fold then | |
1871 | return; | |
1872 | end if; | |
1873 | ||
1874 | -- Compile time evaluation of logical operation | |
1875 | ||
1876 | declare | |
1877 | Left_Int : constant Uint := Expr_Value (Left); | |
1878 | Right_Int : constant Uint := Expr_Value (Right); | |
1879 | ||
1880 | begin | |
1881 | if Is_Modular_Integer_Type (Etype (N)) then | |
1882 | declare | |
1883 | Left_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1); | |
1884 | Right_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1); | |
1885 | ||
1886 | begin | |
1887 | To_Bits (Left_Int, Left_Bits); | |
1888 | To_Bits (Right_Int, Right_Bits); | |
1889 | ||
1890 | -- Note: should really be able to use array ops instead of | |
1891 | -- these loops, but they weren't working at the time ??? | |
1892 | ||
1893 | if Nkind (N) = N_Op_And then | |
1894 | for J in Left_Bits'Range loop | |
1895 | Left_Bits (J) := Left_Bits (J) and Right_Bits (J); | |
1896 | end loop; | |
1897 | ||
1898 | elsif Nkind (N) = N_Op_Or then | |
1899 | for J in Left_Bits'Range loop | |
1900 | Left_Bits (J) := Left_Bits (J) or Right_Bits (J); | |
1901 | end loop; | |
1902 | ||
1903 | else | |
1904 | pragma Assert (Nkind (N) = N_Op_Xor); | |
1905 | ||
1906 | for J in Left_Bits'Range loop | |
1907 | Left_Bits (J) := Left_Bits (J) xor Right_Bits (J); | |
1908 | end loop; | |
1909 | end if; | |
1910 | ||
fbf5a39b | 1911 | Fold_Uint (N, From_Bits (Left_Bits, Etype (N)), Stat); |
996ae0b0 RK |
1912 | end; |
1913 | ||
1914 | else | |
1915 | pragma Assert (Is_Boolean_Type (Etype (N))); | |
1916 | ||
1917 | if Nkind (N) = N_Op_And then | |
1918 | Fold_Uint (N, | |
fbf5a39b | 1919 | Test (Is_True (Left_Int) and then Is_True (Right_Int)), Stat); |
996ae0b0 RK |
1920 | |
1921 | elsif Nkind (N) = N_Op_Or then | |
1922 | Fold_Uint (N, | |
fbf5a39b | 1923 | Test (Is_True (Left_Int) or else Is_True (Right_Int)), Stat); |
996ae0b0 RK |
1924 | |
1925 | else | |
1926 | pragma Assert (Nkind (N) = N_Op_Xor); | |
1927 | Fold_Uint (N, | |
fbf5a39b | 1928 | Test (Is_True (Left_Int) xor Is_True (Right_Int)), Stat); |
996ae0b0 RK |
1929 | end if; |
1930 | end if; | |
996ae0b0 RK |
1931 | end; |
1932 | end Eval_Logical_Op; | |
1933 | ||
1934 | ------------------------ | |
1935 | -- Eval_Membership_Op -- | |
1936 | ------------------------ | |
1937 | ||
1938 | -- A membership test is potentially static if the expression is static, | |
1939 | -- and the range is a potentially static range, or is a subtype mark | |
1940 | -- denoting a static subtype (RM 4.9(12)). | |
1941 | ||
1942 | procedure Eval_Membership_Op (N : Node_Id) is | |
1943 | Left : constant Node_Id := Left_Opnd (N); | |
1944 | Right : constant Node_Id := Right_Opnd (N); | |
1945 | Def_Id : Entity_Id; | |
1946 | Lo : Node_Id; | |
1947 | Hi : Node_Id; | |
1948 | Result : Boolean; | |
1949 | Stat : Boolean; | |
1950 | Fold : Boolean; | |
1951 | ||
1952 | begin | |
1953 | -- Ignore if error in either operand, except to make sure that | |
1954 | -- Any_Type is properly propagated to avoid junk cascaded errors. | |
1955 | ||
1956 | if Etype (Left) = Any_Type | |
1957 | or else Etype (Right) = Any_Type | |
1958 | then | |
1959 | Set_Etype (N, Any_Type); | |
1960 | return; | |
1961 | end if; | |
1962 | ||
1963 | -- Case of right operand is a subtype name | |
1964 | ||
1965 | if Is_Entity_Name (Right) then | |
1966 | Def_Id := Entity (Right); | |
1967 | ||
1968 | if (Is_Scalar_Type (Def_Id) or else Is_String_Type (Def_Id)) | |
1969 | and then Is_OK_Static_Subtype (Def_Id) | |
1970 | then | |
1971 | Test_Expression_Is_Foldable (N, Left, Stat, Fold); | |
1972 | ||
1973 | if not Fold or else not Stat then | |
1974 | return; | |
1975 | end if; | |
1976 | else | |
1977 | Check_Non_Static_Context (Left); | |
1978 | return; | |
1979 | end if; | |
1980 | ||
1981 | -- For string membership tests we will check the length | |
1982 | -- further below. | |
1983 | ||
1984 | if not Is_String_Type (Def_Id) then | |
1985 | Lo := Type_Low_Bound (Def_Id); | |
1986 | Hi := Type_High_Bound (Def_Id); | |
1987 | ||
1988 | else | |
1989 | Lo := Empty; | |
1990 | Hi := Empty; | |
1991 | end if; | |
1992 | ||
1993 | -- Case of right operand is a range | |
1994 | ||
1995 | else | |
1996 | if Is_Static_Range (Right) then | |
1997 | Test_Expression_Is_Foldable (N, Left, Stat, Fold); | |
1998 | ||
1999 | if not Fold or else not Stat then | |
2000 | return; | |
2001 | ||
2002 | -- If one bound of range raises CE, then don't try to fold | |
2003 | ||
2004 | elsif not Is_OK_Static_Range (Right) then | |
2005 | Check_Non_Static_Context (Left); | |
2006 | return; | |
2007 | end if; | |
2008 | ||
2009 | else | |
2010 | Check_Non_Static_Context (Left); | |
2011 | return; | |
2012 | end if; | |
2013 | ||
2014 | -- Here we know range is an OK static range | |
2015 | ||
2016 | Lo := Low_Bound (Right); | |
2017 | Hi := High_Bound (Right); | |
2018 | end if; | |
2019 | ||
2020 | -- For strings we check that the length of the string expression is | |
2021 | -- compatible with the string subtype if the subtype is constrained, | |
2022 | -- or if unconstrained then the test is always true. | |
2023 | ||
2024 | if Is_String_Type (Etype (Right)) then | |
2025 | if not Is_Constrained (Etype (Right)) then | |
2026 | Result := True; | |
2027 | ||
2028 | else | |
2029 | declare | |
2030 | Typlen : constant Uint := String_Type_Len (Etype (Right)); | |
2031 | Strlen : constant Uint := | |
2032 | UI_From_Int (String_Length (Strval (Get_String_Val (Left)))); | |
2033 | begin | |
2034 | Result := (Typlen = Strlen); | |
2035 | end; | |
2036 | end if; | |
2037 | ||
2038 | -- Fold the membership test. We know we have a static range and Lo | |
2039 | -- and Hi are set to the expressions for the end points of this range. | |
2040 | ||
2041 | elsif Is_Real_Type (Etype (Right)) then | |
2042 | declare | |
2043 | Leftval : constant Ureal := Expr_Value_R (Left); | |
2044 | ||
2045 | begin | |
2046 | Result := Expr_Value_R (Lo) <= Leftval | |
2047 | and then Leftval <= Expr_Value_R (Hi); | |
2048 | end; | |
2049 | ||
2050 | else | |
2051 | declare | |
2052 | Leftval : constant Uint := Expr_Value (Left); | |
2053 | ||
2054 | begin | |
2055 | Result := Expr_Value (Lo) <= Leftval | |
2056 | and then Leftval <= Expr_Value (Hi); | |
2057 | end; | |
2058 | end if; | |
2059 | ||
2060 | if Nkind (N) = N_Not_In then | |
2061 | Result := not Result; | |
2062 | end if; | |
2063 | ||
fbf5a39b | 2064 | Fold_Uint (N, Test (Result), True); |
996ae0b0 | 2065 | Warn_On_Known_Condition (N); |
996ae0b0 RK |
2066 | end Eval_Membership_Op; |
2067 | ||
2068 | ------------------------ | |
2069 | -- Eval_Named_Integer -- | |
2070 | ------------------------ | |
2071 | ||
2072 | procedure Eval_Named_Integer (N : Node_Id) is | |
2073 | begin | |
2074 | Fold_Uint (N, | |
fbf5a39b | 2075 | Expr_Value (Expression (Declaration_Node (Entity (N)))), True); |
996ae0b0 RK |
2076 | end Eval_Named_Integer; |
2077 | ||
2078 | --------------------- | |
2079 | -- Eval_Named_Real -- | |
2080 | --------------------- | |
2081 | ||
2082 | procedure Eval_Named_Real (N : Node_Id) is | |
2083 | begin | |
2084 | Fold_Ureal (N, | |
fbf5a39b | 2085 | Expr_Value_R (Expression (Declaration_Node (Entity (N)))), True); |
996ae0b0 RK |
2086 | end Eval_Named_Real; |
2087 | ||
2088 | ------------------- | |
2089 | -- Eval_Op_Expon -- | |
2090 | ------------------- | |
2091 | ||
2092 | -- Exponentiation is a static functions, so the result is potentially | |
2093 | -- static if both operands are potentially static (RM 4.9(7), 4.9(20)). | |
2094 | ||
2095 | procedure Eval_Op_Expon (N : Node_Id) is | |
2096 | Left : constant Node_Id := Left_Opnd (N); | |
2097 | Right : constant Node_Id := Right_Opnd (N); | |
2098 | Stat : Boolean; | |
2099 | Fold : Boolean; | |
2100 | ||
2101 | begin | |
2102 | -- If not foldable we are done | |
2103 | ||
2104 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
2105 | ||
2106 | if not Fold then | |
2107 | return; | |
2108 | end if; | |
2109 | ||
2110 | -- Fold exponentiation operation | |
2111 | ||
2112 | declare | |
2113 | Right_Int : constant Uint := Expr_Value (Right); | |
2114 | ||
2115 | begin | |
2116 | -- Integer case | |
2117 | ||
2118 | if Is_Integer_Type (Etype (Left)) then | |
2119 | declare | |
2120 | Left_Int : constant Uint := Expr_Value (Left); | |
2121 | Result : Uint; | |
2122 | ||
2123 | begin | |
2124 | -- Exponentiation of an integer raises the exception | |
2125 | -- Constraint_Error for a negative exponent (RM 4.5.6) | |
2126 | ||
2127 | if Right_Int < 0 then | |
2128 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
2129 | (N, "integer exponent negative", |
2130 | CE_Range_Check_Failed, | |
2131 | Warn => not Stat); | |
996ae0b0 RK |
2132 | return; |
2133 | ||
2134 | else | |
2135 | if OK_Bits (N, Num_Bits (Left_Int) * Right_Int) then | |
2136 | Result := Left_Int ** Right_Int; | |
2137 | else | |
2138 | Result := Left_Int; | |
2139 | end if; | |
2140 | ||
2141 | if Is_Modular_Integer_Type (Etype (N)) then | |
2142 | Result := Result mod Modulus (Etype (N)); | |
2143 | end if; | |
2144 | ||
fbf5a39b | 2145 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
2146 | end if; |
2147 | end; | |
2148 | ||
2149 | -- Real case | |
2150 | ||
2151 | else | |
2152 | declare | |
2153 | Left_Real : constant Ureal := Expr_Value_R (Left); | |
2154 | ||
2155 | begin | |
2156 | -- Cannot have a zero base with a negative exponent | |
2157 | ||
2158 | if UR_Is_Zero (Left_Real) then | |
2159 | ||
2160 | if Right_Int < 0 then | |
2161 | Apply_Compile_Time_Constraint_Error | |
fbf5a39b AC |
2162 | (N, "zero ** negative integer", |
2163 | CE_Range_Check_Failed, | |
2164 | Warn => not Stat); | |
996ae0b0 RK |
2165 | return; |
2166 | else | |
fbf5a39b | 2167 | Fold_Ureal (N, Ureal_0, Stat); |
996ae0b0 RK |
2168 | end if; |
2169 | ||
2170 | else | |
fbf5a39b | 2171 | Fold_Ureal (N, Left_Real ** Right_Int, Stat); |
996ae0b0 RK |
2172 | end if; |
2173 | end; | |
2174 | end if; | |
996ae0b0 RK |
2175 | end; |
2176 | end Eval_Op_Expon; | |
2177 | ||
2178 | ----------------- | |
2179 | -- Eval_Op_Not -- | |
2180 | ----------------- | |
2181 | ||
2182 | -- The not operation is a static functions, so the result is potentially | |
2183 | -- static if the operand is potentially static (RM 4.9(7), 4.9(20)). | |
2184 | ||
2185 | procedure Eval_Op_Not (N : Node_Id) is | |
2186 | Right : constant Node_Id := Right_Opnd (N); | |
2187 | Stat : Boolean; | |
2188 | Fold : Boolean; | |
2189 | ||
2190 | begin | |
2191 | -- If not foldable we are done | |
2192 | ||
2193 | Test_Expression_Is_Foldable (N, Right, Stat, Fold); | |
2194 | ||
2195 | if not Fold then | |
2196 | return; | |
2197 | end if; | |
2198 | ||
2199 | -- Fold not operation | |
2200 | ||
2201 | declare | |
2202 | Rint : constant Uint := Expr_Value (Right); | |
2203 | Typ : constant Entity_Id := Etype (N); | |
2204 | ||
2205 | begin | |
2206 | -- Negation is equivalent to subtracting from the modulus minus | |
2207 | -- one. For a binary modulus this is equivalent to the ones- | |
2208 | -- component of the original value. For non-binary modulus this | |
2209 | -- is an arbitrary but consistent definition. | |
2210 | ||
2211 | if Is_Modular_Integer_Type (Typ) then | |
fbf5a39b | 2212 | Fold_Uint (N, Modulus (Typ) - 1 - Rint, Stat); |
996ae0b0 RK |
2213 | |
2214 | else | |
2215 | pragma Assert (Is_Boolean_Type (Typ)); | |
fbf5a39b | 2216 | Fold_Uint (N, Test (not Is_True (Rint)), Stat); |
996ae0b0 RK |
2217 | end if; |
2218 | ||
2219 | Set_Is_Static_Expression (N, Stat); | |
2220 | end; | |
2221 | end Eval_Op_Not; | |
2222 | ||
2223 | ------------------------------- | |
2224 | -- Eval_Qualified_Expression -- | |
2225 | ------------------------------- | |
2226 | ||
2227 | -- A qualified expression is potentially static if its subtype mark denotes | |
2228 | -- a static subtype and its expression is potentially static (RM 4.9 (11)). | |
2229 | ||
2230 | procedure Eval_Qualified_Expression (N : Node_Id) is | |
2231 | Operand : constant Node_Id := Expression (N); | |
2232 | Target_Type : constant Entity_Id := Entity (Subtype_Mark (N)); | |
2233 | ||
07fc65c4 GB |
2234 | Stat : Boolean; |
2235 | Fold : Boolean; | |
2236 | Hex : Boolean; | |
996ae0b0 RK |
2237 | |
2238 | begin | |
2239 | -- Can only fold if target is string or scalar and subtype is static | |
2240 | -- Also, do not fold if our parent is an allocator (this is because | |
2241 | -- the qualified expression is really part of the syntactic structure | |
2242 | -- of an allocator, and we do not want to end up with something that | |
2243 | -- corresponds to "new 1" where the 1 is the result of folding a | |
2244 | -- qualified expression). | |
2245 | ||
2246 | if not Is_Static_Subtype (Target_Type) | |
2247 | or else Nkind (Parent (N)) = N_Allocator | |
2248 | then | |
2249 | Check_Non_Static_Context (Operand); | |
af152989 AC |
2250 | |
2251 | -- If operand is known to raise constraint_error, set the | |
2252 | -- flag on the expression so it does not get optimized away. | |
2253 | ||
2254 | if Nkind (Operand) = N_Raise_Constraint_Error then | |
2255 | Set_Raises_Constraint_Error (N); | |
2256 | end if; | |
7324bf49 | 2257 | |
996ae0b0 RK |
2258 | return; |
2259 | end if; | |
2260 | ||
2261 | -- If not foldable we are done | |
2262 | ||
2263 | Test_Expression_Is_Foldable (N, Operand, Stat, Fold); | |
2264 | ||
2265 | if not Fold then | |
2266 | return; | |
2267 | ||
2268 | -- Don't try fold if target type has constraint error bounds | |
2269 | ||
2270 | elsif not Is_OK_Static_Subtype (Target_Type) then | |
2271 | Set_Raises_Constraint_Error (N); | |
2272 | return; | |
2273 | end if; | |
2274 | ||
07fc65c4 GB |
2275 | -- Here we will fold, save Print_In_Hex indication |
2276 | ||
2277 | Hex := Nkind (Operand) = N_Integer_Literal | |
2278 | and then Print_In_Hex (Operand); | |
2279 | ||
996ae0b0 RK |
2280 | -- Fold the result of qualification |
2281 | ||
2282 | if Is_Discrete_Type (Target_Type) then | |
fbf5a39b | 2283 | Fold_Uint (N, Expr_Value (Operand), Stat); |
996ae0b0 | 2284 | |
07fc65c4 GB |
2285 | -- Preserve Print_In_Hex indication |
2286 | ||
2287 | if Hex and then Nkind (N) = N_Integer_Literal then | |
2288 | Set_Print_In_Hex (N); | |
2289 | end if; | |
2290 | ||
996ae0b0 | 2291 | elsif Is_Real_Type (Target_Type) then |
fbf5a39b | 2292 | Fold_Ureal (N, Expr_Value_R (Operand), Stat); |
996ae0b0 RK |
2293 | |
2294 | else | |
fbf5a39b | 2295 | Fold_Str (N, Strval (Get_String_Val (Operand)), Stat); |
996ae0b0 RK |
2296 | |
2297 | if not Stat then | |
2298 | Set_Is_Static_Expression (N, False); | |
2299 | else | |
2300 | Check_String_Literal_Length (N, Target_Type); | |
2301 | end if; | |
2302 | ||
2303 | return; | |
2304 | end if; | |
2305 | ||
fbf5a39b AC |
2306 | -- The expression may be foldable but not static |
2307 | ||
2308 | Set_Is_Static_Expression (N, Stat); | |
2309 | ||
c800f862 | 2310 | if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then |
996ae0b0 RK |
2311 | Out_Of_Range (N); |
2312 | end if; | |
996ae0b0 RK |
2313 | end Eval_Qualified_Expression; |
2314 | ||
2315 | ----------------------- | |
2316 | -- Eval_Real_Literal -- | |
2317 | ----------------------- | |
2318 | ||
2319 | -- Numeric literals are static (RM 4.9(1)), and have already been marked | |
2320 | -- as static by the analyzer. The reason we did it that early is to allow | |
2321 | -- the possibility of turning off the Is_Static_Expression flag after | |
2322 | -- analysis, but before resolution, when integer literals are generated | |
2323 | -- in the expander that do not correspond to static expressions. | |
2324 | ||
2325 | procedure Eval_Real_Literal (N : Node_Id) is | |
a1980be8 GB |
2326 | PK : constant Node_Kind := Nkind (Parent (N)); |
2327 | ||
996ae0b0 | 2328 | begin |
a1980be8 GB |
2329 | -- If the literal appears in a non-expression context |
2330 | -- and not as part of a number declaration, then it is | |
2331 | -- appearing in a non-static context, so check it. | |
996ae0b0 | 2332 | |
a1980be8 | 2333 | if PK not in N_Subexpr and then PK /= N_Number_Declaration then |
996ae0b0 RK |
2334 | Check_Non_Static_Context (N); |
2335 | end if; | |
996ae0b0 RK |
2336 | end Eval_Real_Literal; |
2337 | ||
2338 | ------------------------ | |
2339 | -- Eval_Relational_Op -- | |
2340 | ------------------------ | |
2341 | ||
2342 | -- Relational operations are static functions, so the result is static | |
2343 | -- if both operands are static (RM 4.9(7), 4.9(20)). | |
2344 | ||
2345 | procedure Eval_Relational_Op (N : Node_Id) is | |
2346 | Left : constant Node_Id := Left_Opnd (N); | |
2347 | Right : constant Node_Id := Right_Opnd (N); | |
2348 | Typ : constant Entity_Id := Etype (Left); | |
2349 | Result : Boolean; | |
2350 | Stat : Boolean; | |
2351 | Fold : Boolean; | |
2352 | ||
2353 | begin | |
45fc7ddb HK |
2354 | -- One special case to deal with first. If we can tell that the result |
2355 | -- will be false because the lengths of one or more index subtypes are | |
2356 | -- compile time known and different, then we can replace the entire | |
2357 | -- result by False. We only do this for one dimensional arrays, because | |
2358 | -- the case of multi-dimensional arrays is rare and too much trouble! If | |
2359 | -- one of the operands is an illegal aggregate, its type might still be | |
2360 | -- an arbitrary composite type, so nothing to do. | |
996ae0b0 RK |
2361 | |
2362 | if Is_Array_Type (Typ) | |
13f34a3f | 2363 | and then Typ /= Any_Composite |
996ae0b0 | 2364 | and then Number_Dimensions (Typ) = 1 |
13f34a3f | 2365 | and then (Nkind (N) = N_Op_Eq or else Nkind (N) = N_Op_Ne) |
996ae0b0 RK |
2366 | then |
2367 | if Raises_Constraint_Error (Left) | |
2368 | or else Raises_Constraint_Error (Right) | |
2369 | then | |
2370 | return; | |
2371 | end if; | |
2372 | ||
45fc7ddb HK |
2373 | -- OK, we have the case where we may be able to do this fold |
2374 | ||
2375 | Length_Mismatch : declare | |
996ae0b0 | 2376 | procedure Get_Static_Length (Op : Node_Id; Len : out Uint); |
13f34a3f RD |
2377 | -- If Op is an expression for a constrained array with a known |
2378 | -- at compile time length, then Len is set to this (non-negative | |
2379 | -- length). Otherwise Len is set to minus 1. | |
996ae0b0 | 2380 | |
fbf5a39b AC |
2381 | ----------------------- |
2382 | -- Get_Static_Length -- | |
2383 | ----------------------- | |
2384 | ||
996ae0b0 RK |
2385 | procedure Get_Static_Length (Op : Node_Id; Len : out Uint) is |
2386 | T : Entity_Id; | |
2387 | ||
2388 | begin | |
45fc7ddb HK |
2389 | -- First easy case string literal |
2390 | ||
996ae0b0 RK |
2391 | if Nkind (Op) = N_String_Literal then |
2392 | Len := UI_From_Int (String_Length (Strval (Op))); | |
45fc7ddb HK |
2393 | return; |
2394 | end if; | |
2395 | ||
2396 | -- Second easy case, not constrained subtype, so no length | |
996ae0b0 | 2397 | |
45fc7ddb | 2398 | if not Is_Constrained (Etype (Op)) then |
996ae0b0 | 2399 | Len := Uint_Minus_1; |
45fc7ddb HK |
2400 | return; |
2401 | end if; | |
996ae0b0 | 2402 | |
45fc7ddb HK |
2403 | -- General case |
2404 | ||
2405 | T := Etype (First_Index (Etype (Op))); | |
2406 | ||
2407 | -- The simple case, both bounds are known at compile time | |
2408 | ||
2409 | if Is_Discrete_Type (T) | |
2410 | and then | |
2411 | Compile_Time_Known_Value (Type_Low_Bound (T)) | |
2412 | and then | |
2413 | Compile_Time_Known_Value (Type_High_Bound (T)) | |
2414 | then | |
2415 | Len := UI_Max (Uint_0, | |
2416 | Expr_Value (Type_High_Bound (T)) - | |
2417 | Expr_Value (Type_Low_Bound (T)) + 1); | |
2418 | return; | |
2419 | end if; | |
2420 | ||
2421 | -- A more complex case, where the bounds are of the form | |
2422 | -- X [+/- K1] .. X [+/- K2]), where X is an expression that is | |
2423 | -- either A'First or A'Last (with A an entity name), or X is an | |
2424 | -- entity name, and the two X's are the same and K1 and K2 are | |
2425 | -- known at compile time, in this case, the length can also be | |
2426 | -- computed at compile time, even though the bounds are not | |
2427 | -- known. A common case of this is e.g. (X'First..X'First+5). | |
2428 | ||
2429 | Extract_Length : declare | |
2430 | procedure Decompose_Expr | |
2431 | (Expr : Node_Id; | |
2432 | Ent : out Entity_Id; | |
2433 | Kind : out Character; | |
2434 | Cons : out Uint); | |
2435 | -- Given an expression, see if is of the form above, | |
2436 | -- X [+/- K]. If so Ent is set to the entity in X, | |
2437 | -- Kind is 'F','L','E' for 'First/'Last/simple entity, | |
2438 | -- and Cons is the value of K. If the expression is | |
2439 | -- not of the required form, Ent is set to Empty. | |
2440 | ||
2441 | -------------------- | |
2442 | -- Decompose_Expr -- | |
2443 | -------------------- | |
2444 | ||
2445 | procedure Decompose_Expr | |
2446 | (Expr : Node_Id; | |
2447 | Ent : out Entity_Id; | |
2448 | Kind : out Character; | |
2449 | Cons : out Uint) | |
2450 | is | |
2451 | Exp : Node_Id; | |
2452 | ||
2453 | begin | |
2454 | if Nkind (Expr) = N_Op_Add | |
2455 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
2456 | then | |
2457 | Exp := Left_Opnd (Expr); | |
2458 | Cons := Expr_Value (Right_Opnd (Expr)); | |
2459 | ||
2460 | elsif Nkind (Expr) = N_Op_Subtract | |
2461 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
2462 | then | |
2463 | Exp := Left_Opnd (Expr); | |
2464 | Cons := -Expr_Value (Right_Opnd (Expr)); | |
996ae0b0 | 2465 | |
45fc7ddb HK |
2466 | else |
2467 | Exp := Expr; | |
2468 | Cons := Uint_0; | |
2469 | end if; | |
2470 | ||
2471 | -- At this stage Exp is set to the potential X | |
2472 | ||
2473 | if Nkind (Exp) = N_Attribute_Reference then | |
2474 | if Attribute_Name (Exp) = Name_First then | |
2475 | Kind := 'F'; | |
2476 | elsif Attribute_Name (Exp) = Name_Last then | |
2477 | Kind := 'L'; | |
2478 | else | |
2479 | Ent := Empty; | |
2480 | return; | |
2481 | end if; | |
2482 | ||
2483 | Exp := Prefix (Exp); | |
2484 | ||
2485 | else | |
2486 | Kind := 'E'; | |
2487 | end if; | |
2488 | ||
2489 | if Is_Entity_Name (Exp) | |
2490 | and then Present (Entity (Exp)) | |
2491 | then | |
2492 | Ent := Entity (Exp); | |
2493 | else | |
2494 | Ent := Empty; | |
2495 | end if; | |
2496 | end Decompose_Expr; | |
2497 | ||
2498 | -- Local Variables | |
2499 | ||
2500 | Ent1, Ent2 : Entity_Id; | |
2501 | Kind1, Kind2 : Character; | |
2502 | Cons1, Cons2 : Uint; | |
2503 | ||
2504 | -- Start of processing for Extract_Length | |
2505 | ||
2506 | begin | |
2507 | Decompose_Expr (Type_Low_Bound (T), Ent1, Kind1, Cons1); | |
2508 | Decompose_Expr (Type_High_Bound (T), Ent2, Kind2, Cons2); | |
2509 | ||
2510 | if Present (Ent1) | |
2511 | and then Kind1 = Kind2 | |
2512 | and then Ent1 = Ent2 | |
996ae0b0 | 2513 | then |
45fc7ddb | 2514 | Len := Cons2 - Cons1 + 1; |
996ae0b0 RK |
2515 | else |
2516 | Len := Uint_Minus_1; | |
2517 | end if; | |
45fc7ddb | 2518 | end Extract_Length; |
996ae0b0 RK |
2519 | end Get_Static_Length; |
2520 | ||
45fc7ddb HK |
2521 | -- Local Variables |
2522 | ||
996ae0b0 RK |
2523 | Len_L : Uint; |
2524 | Len_R : Uint; | |
2525 | ||
45fc7ddb HK |
2526 | -- Start of processing for Length_Mismatch |
2527 | ||
996ae0b0 RK |
2528 | begin |
2529 | Get_Static_Length (Left, Len_L); | |
2530 | Get_Static_Length (Right, Len_R); | |
2531 | ||
2532 | if Len_L /= Uint_Minus_1 | |
2533 | and then Len_R /= Uint_Minus_1 | |
2534 | and then Len_L /= Len_R | |
2535 | then | |
fbf5a39b | 2536 | Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False); |
996ae0b0 RK |
2537 | Warn_On_Known_Condition (N); |
2538 | return; | |
2539 | end if; | |
45fc7ddb HK |
2540 | end Length_Mismatch; |
2541 | end if; | |
6eaf4095 | 2542 | |
7a3f77d2 AC |
2543 | -- Another special case: comparisons of access types, where one or both |
2544 | -- operands are known to be null, so the result can be determined. | |
6eaf4095 | 2545 | |
45fc7ddb | 2546 | if Is_Access_Type (Typ) then |
7a3f77d2 AC |
2547 | if Known_Null (Left) then |
2548 | if Known_Null (Right) then | |
2549 | Fold_Uint (N, Test (Nkind (N) = N_Op_Eq), False); | |
2550 | Warn_On_Known_Condition (N); | |
2551 | return; | |
2552 | ||
2553 | elsif Known_Non_Null (Right) then | |
2554 | Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False); | |
2555 | Warn_On_Known_Condition (N); | |
2556 | return; | |
2557 | end if; | |
2558 | ||
2559 | elsif Known_Non_Null (Left) then | |
2560 | if Known_Null (Right) then | |
2561 | Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False); | |
2562 | Warn_On_Known_Condition (N); | |
2563 | return; | |
2564 | end if; | |
2565 | end if; | |
996ae0b0 RK |
2566 | end if; |
2567 | ||
2568 | -- Can only fold if type is scalar (don't fold string ops) | |
2569 | ||
2570 | if not Is_Scalar_Type (Typ) then | |
2571 | Check_Non_Static_Context (Left); | |
2572 | Check_Non_Static_Context (Right); | |
2573 | return; | |
2574 | end if; | |
2575 | ||
2576 | -- If not foldable we are done | |
2577 | ||
2578 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
2579 | ||
2580 | if not Fold then | |
2581 | return; | |
2582 | end if; | |
2583 | ||
2584 | -- Integer and Enumeration (discrete) type cases | |
2585 | ||
2586 | if Is_Discrete_Type (Typ) then | |
2587 | declare | |
2588 | Left_Int : constant Uint := Expr_Value (Left); | |
2589 | Right_Int : constant Uint := Expr_Value (Right); | |
2590 | ||
2591 | begin | |
2592 | case Nkind (N) is | |
2593 | when N_Op_Eq => Result := Left_Int = Right_Int; | |
2594 | when N_Op_Ne => Result := Left_Int /= Right_Int; | |
2595 | when N_Op_Lt => Result := Left_Int < Right_Int; | |
2596 | when N_Op_Le => Result := Left_Int <= Right_Int; | |
2597 | when N_Op_Gt => Result := Left_Int > Right_Int; | |
2598 | when N_Op_Ge => Result := Left_Int >= Right_Int; | |
2599 | ||
2600 | when others => | |
2601 | raise Program_Error; | |
2602 | end case; | |
2603 | ||
fbf5a39b | 2604 | Fold_Uint (N, Test (Result), Stat); |
996ae0b0 RK |
2605 | end; |
2606 | ||
2607 | -- Real type case | |
2608 | ||
2609 | else | |
2610 | pragma Assert (Is_Real_Type (Typ)); | |
2611 | ||
2612 | declare | |
2613 | Left_Real : constant Ureal := Expr_Value_R (Left); | |
2614 | Right_Real : constant Ureal := Expr_Value_R (Right); | |
2615 | ||
2616 | begin | |
2617 | case Nkind (N) is | |
2618 | when N_Op_Eq => Result := (Left_Real = Right_Real); | |
2619 | when N_Op_Ne => Result := (Left_Real /= Right_Real); | |
2620 | when N_Op_Lt => Result := (Left_Real < Right_Real); | |
2621 | when N_Op_Le => Result := (Left_Real <= Right_Real); | |
2622 | when N_Op_Gt => Result := (Left_Real > Right_Real); | |
2623 | when N_Op_Ge => Result := (Left_Real >= Right_Real); | |
2624 | ||
2625 | when others => | |
2626 | raise Program_Error; | |
2627 | end case; | |
2628 | ||
fbf5a39b | 2629 | Fold_Uint (N, Test (Result), Stat); |
996ae0b0 RK |
2630 | end; |
2631 | end if; | |
2632 | ||
996ae0b0 RK |
2633 | Warn_On_Known_Condition (N); |
2634 | end Eval_Relational_Op; | |
2635 | ||
2636 | ---------------- | |
2637 | -- Eval_Shift -- | |
2638 | ---------------- | |
2639 | ||
2640 | -- Shift operations are intrinsic operations that can never be static, | |
2641 | -- so the only processing required is to perform the required check for | |
2642 | -- a non static context for the two operands. | |
2643 | ||
2644 | -- Actually we could do some compile time evaluation here some time ??? | |
2645 | ||
2646 | procedure Eval_Shift (N : Node_Id) is | |
2647 | begin | |
2648 | Check_Non_Static_Context (Left_Opnd (N)); | |
2649 | Check_Non_Static_Context (Right_Opnd (N)); | |
2650 | end Eval_Shift; | |
2651 | ||
2652 | ------------------------ | |
2653 | -- Eval_Short_Circuit -- | |
2654 | ------------------------ | |
2655 | ||
2656 | -- A short circuit operation is potentially static if both operands | |
2657 | -- are potentially static (RM 4.9 (13)) | |
2658 | ||
2659 | procedure Eval_Short_Circuit (N : Node_Id) is | |
2660 | Kind : constant Node_Kind := Nkind (N); | |
2661 | Left : constant Node_Id := Left_Opnd (N); | |
2662 | Right : constant Node_Id := Right_Opnd (N); | |
2663 | Left_Int : Uint; | |
2664 | Rstat : constant Boolean := | |
2665 | Is_Static_Expression (Left) | |
2666 | and then Is_Static_Expression (Right); | |
2667 | ||
2668 | begin | |
2669 | -- Short circuit operations are never static in Ada 83 | |
2670 | ||
0ab80019 | 2671 | if Ada_Version = Ada_83 |
996ae0b0 RK |
2672 | and then Comes_From_Source (N) |
2673 | then | |
2674 | Check_Non_Static_Context (Left); | |
2675 | Check_Non_Static_Context (Right); | |
2676 | return; | |
2677 | end if; | |
2678 | ||
2679 | -- Now look at the operands, we can't quite use the normal call to | |
2680 | -- Test_Expression_Is_Foldable here because short circuit operations | |
2681 | -- are a special case, they can still be foldable, even if the right | |
2682 | -- operand raises constraint error. | |
2683 | ||
2684 | -- If either operand is Any_Type, just propagate to result and | |
2685 | -- do not try to fold, this prevents cascaded errors. | |
2686 | ||
2687 | if Etype (Left) = Any_Type or else Etype (Right) = Any_Type then | |
2688 | Set_Etype (N, Any_Type); | |
2689 | return; | |
2690 | ||
2691 | -- If left operand raises constraint error, then replace node N with | |
2692 | -- the raise constraint error node, and we are obviously not foldable. | |
2693 | -- Is_Static_Expression is set from the two operands in the normal way, | |
2694 | -- and we check the right operand if it is in a non-static context. | |
2695 | ||
2696 | elsif Raises_Constraint_Error (Left) then | |
2697 | if not Rstat then | |
2698 | Check_Non_Static_Context (Right); | |
2699 | end if; | |
2700 | ||
2701 | Rewrite_In_Raise_CE (N, Left); | |
2702 | Set_Is_Static_Expression (N, Rstat); | |
2703 | return; | |
2704 | ||
2705 | -- If the result is not static, then we won't in any case fold | |
2706 | ||
2707 | elsif not Rstat then | |
2708 | Check_Non_Static_Context (Left); | |
2709 | Check_Non_Static_Context (Right); | |
2710 | return; | |
2711 | end if; | |
2712 | ||
2713 | -- Here the result is static, note that, unlike the normal processing | |
2714 | -- in Test_Expression_Is_Foldable, we did *not* check above to see if | |
2715 | -- the right operand raises constraint error, that's because it is not | |
2716 | -- significant if the left operand is decisive. | |
2717 | ||
2718 | Set_Is_Static_Expression (N); | |
2719 | ||
2720 | -- It does not matter if the right operand raises constraint error if | |
2721 | -- it will not be evaluated. So deal specially with the cases where | |
2722 | -- the right operand is not evaluated. Note that we will fold these | |
2723 | -- cases even if the right operand is non-static, which is fine, but | |
2724 | -- of course in these cases the result is not potentially static. | |
2725 | ||
2726 | Left_Int := Expr_Value (Left); | |
2727 | ||
2728 | if (Kind = N_And_Then and then Is_False (Left_Int)) | |
2729 | or else (Kind = N_Or_Else and Is_True (Left_Int)) | |
2730 | then | |
fbf5a39b | 2731 | Fold_Uint (N, Left_Int, Rstat); |
996ae0b0 RK |
2732 | return; |
2733 | end if; | |
2734 | ||
2735 | -- If first operand not decisive, then it does matter if the right | |
2736 | -- operand raises constraint error, since it will be evaluated, so | |
2737 | -- we simply replace the node with the right operand. Note that this | |
2738 | -- properly propagates Is_Static_Expression and Raises_Constraint_Error | |
2739 | -- (both are set to True in Right). | |
2740 | ||
2741 | if Raises_Constraint_Error (Right) then | |
2742 | Rewrite_In_Raise_CE (N, Right); | |
2743 | Check_Non_Static_Context (Left); | |
2744 | return; | |
2745 | end if; | |
2746 | ||
2747 | -- Otherwise the result depends on the right operand | |
2748 | ||
fbf5a39b | 2749 | Fold_Uint (N, Expr_Value (Right), Rstat); |
996ae0b0 | 2750 | return; |
996ae0b0 RK |
2751 | end Eval_Short_Circuit; |
2752 | ||
2753 | ---------------- | |
2754 | -- Eval_Slice -- | |
2755 | ---------------- | |
2756 | ||
2757 | -- Slices can never be static, so the only processing required is to | |
2758 | -- check for non-static context if an explicit range is given. | |
2759 | ||
2760 | procedure Eval_Slice (N : Node_Id) is | |
2761 | Drange : constant Node_Id := Discrete_Range (N); | |
996ae0b0 RK |
2762 | begin |
2763 | if Nkind (Drange) = N_Range then | |
2764 | Check_Non_Static_Context (Low_Bound (Drange)); | |
2765 | Check_Non_Static_Context (High_Bound (Drange)); | |
2766 | end if; | |
cd2fb920 ES |
2767 | |
2768 | -- A slice of the form A (subtype), when the subtype is the index of | |
2769 | -- the type of A, is redundant, the slice can be replaced with A, and | |
2770 | -- this is worth a warning. | |
2771 | ||
2772 | if Is_Entity_Name (Prefix (N)) then | |
2773 | declare | |
2774 | E : constant Entity_Id := Entity (Prefix (N)); | |
2775 | T : constant Entity_Id := Etype (E); | |
2776 | begin | |
2777 | if Ekind (E) = E_Constant | |
2778 | and then Is_Array_Type (T) | |
2779 | and then Is_Entity_Name (Drange) | |
2780 | then | |
2781 | if Is_Entity_Name (Original_Node (First_Index (T))) | |
2782 | and then Entity (Original_Node (First_Index (T))) | |
2783 | = Entity (Drange) | |
2784 | then | |
2785 | if Warn_On_Redundant_Constructs then | |
2786 | Error_Msg_N ("redundant slice denotes whole array?", N); | |
2787 | end if; | |
2788 | ||
2789 | -- The following might be a useful optimization ???? | |
2790 | ||
2791 | -- Rewrite (N, New_Occurrence_Of (E, Sloc (N))); | |
2792 | end if; | |
2793 | end if; | |
2794 | end; | |
2795 | end if; | |
996ae0b0 RK |
2796 | end Eval_Slice; |
2797 | ||
2798 | ------------------------- | |
2799 | -- Eval_String_Literal -- | |
2800 | ------------------------- | |
2801 | ||
2802 | procedure Eval_String_Literal (N : Node_Id) is | |
91b1417d AC |
2803 | Typ : constant Entity_Id := Etype (N); |
2804 | Bas : constant Entity_Id := Base_Type (Typ); | |
2805 | Xtp : Entity_Id; | |
2806 | Len : Nat; | |
2807 | Lo : Node_Id; | |
996ae0b0 RK |
2808 | |
2809 | begin | |
2810 | -- Nothing to do if error type (handles cases like default expressions | |
2811 | -- or generics where we have not yet fully resolved the type) | |
2812 | ||
91b1417d | 2813 | if Bas = Any_Type or else Bas = Any_String then |
996ae0b0 | 2814 | return; |
91b1417d | 2815 | end if; |
996ae0b0 RK |
2816 | |
2817 | -- String literals are static if the subtype is static (RM 4.9(2)), so | |
2818 | -- reset the static expression flag (it was set unconditionally in | |
2819 | -- Analyze_String_Literal) if the subtype is non-static. We tell if | |
2820 | -- the subtype is static by looking at the lower bound. | |
2821 | ||
91b1417d AC |
2822 | if Ekind (Typ) = E_String_Literal_Subtype then |
2823 | if not Is_OK_Static_Expression (String_Literal_Low_Bound (Typ)) then | |
2824 | Set_Is_Static_Expression (N, False); | |
2825 | return; | |
2826 | end if; | |
2827 | ||
2828 | -- Here if Etype of string literal is normal Etype (not yet possible, | |
2829 | -- but may be possible in future!) | |
2830 | ||
2831 | elsif not Is_OK_Static_Expression | |
2832 | (Type_Low_Bound (Etype (First_Index (Typ)))) | |
2833 | then | |
996ae0b0 | 2834 | Set_Is_Static_Expression (N, False); |
91b1417d AC |
2835 | return; |
2836 | end if; | |
996ae0b0 | 2837 | |
91b1417d AC |
2838 | -- If original node was a type conversion, then result if non-static |
2839 | ||
2840 | if Nkind (Original_Node (N)) = N_Type_Conversion then | |
996ae0b0 | 2841 | Set_Is_Static_Expression (N, False); |
91b1417d AC |
2842 | return; |
2843 | end if; | |
996ae0b0 RK |
2844 | |
2845 | -- Test for illegal Ada 95 cases. A string literal is illegal in | |
2846 | -- Ada 95 if its bounds are outside the index base type and this | |
91b1417d | 2847 | -- index type is static. This can happen in only two ways. Either |
996ae0b0 RK |
2848 | -- the string literal is too long, or it is null, and the lower |
2849 | -- bound is type'First. In either case it is the upper bound that | |
2850 | -- is out of range of the index type. | |
2851 | ||
0ab80019 | 2852 | if Ada_Version >= Ada_95 then |
91b1417d AC |
2853 | if Root_Type (Bas) = Standard_String |
2854 | or else | |
2855 | Root_Type (Bas) = Standard_Wide_String | |
996ae0b0 | 2856 | then |
91b1417d | 2857 | Xtp := Standard_Positive; |
996ae0b0 | 2858 | else |
91b1417d | 2859 | Xtp := Etype (First_Index (Bas)); |
996ae0b0 RK |
2860 | end if; |
2861 | ||
91b1417d AC |
2862 | if Ekind (Typ) = E_String_Literal_Subtype then |
2863 | Lo := String_Literal_Low_Bound (Typ); | |
2864 | else | |
2865 | Lo := Type_Low_Bound (Etype (First_Index (Typ))); | |
2866 | end if; | |
2867 | ||
2868 | Len := String_Length (Strval (N)); | |
2869 | ||
2870 | if UI_From_Int (Len) > String_Type_Len (Bas) then | |
996ae0b0 | 2871 | Apply_Compile_Time_Constraint_Error |
07fc65c4 | 2872 | (N, "string literal too long for}", CE_Length_Check_Failed, |
91b1417d AC |
2873 | Ent => Bas, |
2874 | Typ => First_Subtype (Bas)); | |
996ae0b0 | 2875 | |
91b1417d AC |
2876 | elsif Len = 0 |
2877 | and then not Is_Generic_Type (Xtp) | |
2878 | and then | |
2879 | Expr_Value (Lo) = Expr_Value (Type_Low_Bound (Base_Type (Xtp))) | |
996ae0b0 RK |
2880 | then |
2881 | Apply_Compile_Time_Constraint_Error | |
2882 | (N, "null string literal not allowed for}", | |
07fc65c4 | 2883 | CE_Length_Check_Failed, |
91b1417d AC |
2884 | Ent => Bas, |
2885 | Typ => First_Subtype (Bas)); | |
996ae0b0 RK |
2886 | end if; |
2887 | end if; | |
996ae0b0 RK |
2888 | end Eval_String_Literal; |
2889 | ||
2890 | -------------------------- | |
2891 | -- Eval_Type_Conversion -- | |
2892 | -------------------------- | |
2893 | ||
2894 | -- A type conversion is potentially static if its subtype mark is for a | |
2895 | -- static scalar subtype, and its operand expression is potentially static | |
2896 | -- (RM 4.9 (10)) | |
2897 | ||
2898 | procedure Eval_Type_Conversion (N : Node_Id) is | |
2899 | Operand : constant Node_Id := Expression (N); | |
2900 | Source_Type : constant Entity_Id := Etype (Operand); | |
2901 | Target_Type : constant Entity_Id := Etype (N); | |
2902 | ||
2903 | Stat : Boolean; | |
2904 | Fold : Boolean; | |
2905 | ||
2906 | function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean; | |
2907 | -- Returns true if type T is an integer type, or if it is a | |
2908 | -- fixed-point type to be treated as an integer (i.e. the flag | |
2909 | -- Conversion_OK is set on the conversion node). | |
2910 | ||
2911 | function To_Be_Treated_As_Real (T : Entity_Id) return Boolean; | |
2912 | -- Returns true if type T is a floating-point type, or if it is a | |
2913 | -- fixed-point type that is not to be treated as an integer (i.e. the | |
2914 | -- flag Conversion_OK is not set on the conversion node). | |
2915 | ||
fbf5a39b AC |
2916 | ------------------------------ |
2917 | -- To_Be_Treated_As_Integer -- | |
2918 | ------------------------------ | |
2919 | ||
996ae0b0 RK |
2920 | function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean is |
2921 | begin | |
2922 | return | |
2923 | Is_Integer_Type (T) | |
2924 | or else (Is_Fixed_Point_Type (T) and then Conversion_OK (N)); | |
2925 | end To_Be_Treated_As_Integer; | |
2926 | ||
fbf5a39b AC |
2927 | --------------------------- |
2928 | -- To_Be_Treated_As_Real -- | |
2929 | --------------------------- | |
2930 | ||
996ae0b0 RK |
2931 | function To_Be_Treated_As_Real (T : Entity_Id) return Boolean is |
2932 | begin | |
2933 | return | |
2934 | Is_Floating_Point_Type (T) | |
2935 | or else (Is_Fixed_Point_Type (T) and then not Conversion_OK (N)); | |
2936 | end To_Be_Treated_As_Real; | |
2937 | ||
2938 | -- Start of processing for Eval_Type_Conversion | |
2939 | ||
2940 | begin | |
82c80734 | 2941 | -- Cannot fold if target type is non-static or if semantic error |
996ae0b0 RK |
2942 | |
2943 | if not Is_Static_Subtype (Target_Type) then | |
2944 | Check_Non_Static_Context (Operand); | |
2945 | return; | |
2946 | ||
2947 | elsif Error_Posted (N) then | |
2948 | return; | |
2949 | end if; | |
2950 | ||
2951 | -- If not foldable we are done | |
2952 | ||
2953 | Test_Expression_Is_Foldable (N, Operand, Stat, Fold); | |
2954 | ||
2955 | if not Fold then | |
2956 | return; | |
2957 | ||
2958 | -- Don't try fold if target type has constraint error bounds | |
2959 | ||
2960 | elsif not Is_OK_Static_Subtype (Target_Type) then | |
2961 | Set_Raises_Constraint_Error (N); | |
2962 | return; | |
2963 | end if; | |
2964 | ||
2965 | -- Remaining processing depends on operand types. Note that in the | |
2966 | -- following type test, fixed-point counts as real unless the flag | |
2967 | -- Conversion_OK is set, in which case it counts as integer. | |
2968 | ||
82c80734 | 2969 | -- Fold conversion, case of string type. The result is not static |
996ae0b0 RK |
2970 | |
2971 | if Is_String_Type (Target_Type) then | |
b11e8d6f | 2972 | Fold_Str (N, Strval (Get_String_Val (Operand)), Static => False); |
996ae0b0 RK |
2973 | |
2974 | return; | |
2975 | ||
2976 | -- Fold conversion, case of integer target type | |
2977 | ||
2978 | elsif To_Be_Treated_As_Integer (Target_Type) then | |
2979 | declare | |
2980 | Result : Uint; | |
2981 | ||
2982 | begin | |
2983 | -- Integer to integer conversion | |
2984 | ||
2985 | if To_Be_Treated_As_Integer (Source_Type) then | |
2986 | Result := Expr_Value (Operand); | |
2987 | ||
2988 | -- Real to integer conversion | |
2989 | ||
2990 | else | |
2991 | Result := UR_To_Uint (Expr_Value_R (Operand)); | |
2992 | end if; | |
2993 | ||
2994 | -- If fixed-point type (Conversion_OK must be set), then the | |
2995 | -- result is logically an integer, but we must replace the | |
2996 | -- conversion with the corresponding real literal, since the | |
2997 | -- type from a semantic point of view is still fixed-point. | |
2998 | ||
2999 | if Is_Fixed_Point_Type (Target_Type) then | |
3000 | Fold_Ureal | |
fbf5a39b | 3001 | (N, UR_From_Uint (Result) * Small_Value (Target_Type), Stat); |
996ae0b0 RK |
3002 | |
3003 | -- Otherwise result is integer literal | |
3004 | ||
3005 | else | |
fbf5a39b | 3006 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
3007 | end if; |
3008 | end; | |
3009 | ||
3010 | -- Fold conversion, case of real target type | |
3011 | ||
3012 | elsif To_Be_Treated_As_Real (Target_Type) then | |
3013 | declare | |
3014 | Result : Ureal; | |
3015 | ||
3016 | begin | |
3017 | if To_Be_Treated_As_Real (Source_Type) then | |
3018 | Result := Expr_Value_R (Operand); | |
3019 | else | |
3020 | Result := UR_From_Uint (Expr_Value (Operand)); | |
3021 | end if; | |
3022 | ||
fbf5a39b | 3023 | Fold_Ureal (N, Result, Stat); |
996ae0b0 RK |
3024 | end; |
3025 | ||
3026 | -- Enumeration types | |
3027 | ||
3028 | else | |
fbf5a39b | 3029 | Fold_Uint (N, Expr_Value (Operand), Stat); |
996ae0b0 RK |
3030 | end if; |
3031 | ||
c800f862 | 3032 | if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then |
996ae0b0 RK |
3033 | Out_Of_Range (N); |
3034 | end if; | |
3035 | ||
3036 | end Eval_Type_Conversion; | |
3037 | ||
3038 | ------------------- | |
3039 | -- Eval_Unary_Op -- | |
3040 | ------------------- | |
3041 | ||
3042 | -- Predefined unary operators are static functions (RM 4.9(20)) and thus | |
3043 | -- are potentially static if the operand is potentially static (RM 4.9(7)) | |
3044 | ||
3045 | procedure Eval_Unary_Op (N : Node_Id) is | |
3046 | Right : constant Node_Id := Right_Opnd (N); | |
3047 | Stat : Boolean; | |
3048 | Fold : Boolean; | |
3049 | ||
3050 | begin | |
3051 | -- If not foldable we are done | |
3052 | ||
3053 | Test_Expression_Is_Foldable (N, Right, Stat, Fold); | |
3054 | ||
3055 | if not Fold then | |
3056 | return; | |
3057 | end if; | |
3058 | ||
3059 | -- Fold for integer case | |
3060 | ||
3061 | if Is_Integer_Type (Etype (N)) then | |
3062 | declare | |
3063 | Rint : constant Uint := Expr_Value (Right); | |
3064 | Result : Uint; | |
3065 | ||
3066 | begin | |
3067 | -- In the case of modular unary plus and abs there is no need | |
3068 | -- to adjust the result of the operation since if the original | |
3069 | -- operand was in bounds the result will be in the bounds of the | |
3070 | -- modular type. However, in the case of modular unary minus the | |
3071 | -- result may go out of the bounds of the modular type and needs | |
3072 | -- adjustment. | |
3073 | ||
3074 | if Nkind (N) = N_Op_Plus then | |
3075 | Result := Rint; | |
3076 | ||
3077 | elsif Nkind (N) = N_Op_Minus then | |
3078 | if Is_Modular_Integer_Type (Etype (N)) then | |
3079 | Result := (-Rint) mod Modulus (Etype (N)); | |
3080 | else | |
3081 | Result := (-Rint); | |
3082 | end if; | |
3083 | ||
3084 | else | |
3085 | pragma Assert (Nkind (N) = N_Op_Abs); | |
3086 | Result := abs Rint; | |
3087 | end if; | |
3088 | ||
fbf5a39b | 3089 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
3090 | end; |
3091 | ||
3092 | -- Fold for real case | |
3093 | ||
3094 | elsif Is_Real_Type (Etype (N)) then | |
3095 | declare | |
3096 | Rreal : constant Ureal := Expr_Value_R (Right); | |
3097 | Result : Ureal; | |
3098 | ||
3099 | begin | |
3100 | if Nkind (N) = N_Op_Plus then | |
3101 | Result := Rreal; | |
3102 | ||
3103 | elsif Nkind (N) = N_Op_Minus then | |
3104 | Result := UR_Negate (Rreal); | |
3105 | ||
3106 | else | |
3107 | pragma Assert (Nkind (N) = N_Op_Abs); | |
3108 | Result := abs Rreal; | |
3109 | end if; | |
3110 | ||
fbf5a39b | 3111 | Fold_Ureal (N, Result, Stat); |
996ae0b0 RK |
3112 | end; |
3113 | end if; | |
996ae0b0 RK |
3114 | end Eval_Unary_Op; |
3115 | ||
3116 | ------------------------------- | |
3117 | -- Eval_Unchecked_Conversion -- | |
3118 | ------------------------------- | |
3119 | ||
3120 | -- Unchecked conversions can never be static, so the only required | |
3121 | -- processing is to check for a non-static context for the operand. | |
3122 | ||
3123 | procedure Eval_Unchecked_Conversion (N : Node_Id) is | |
3124 | begin | |
3125 | Check_Non_Static_Context (Expression (N)); | |
3126 | end Eval_Unchecked_Conversion; | |
3127 | ||
3128 | -------------------- | |
3129 | -- Expr_Rep_Value -- | |
3130 | -------------------- | |
3131 | ||
3132 | function Expr_Rep_Value (N : Node_Id) return Uint is | |
07fc65c4 GB |
3133 | Kind : constant Node_Kind := Nkind (N); |
3134 | Ent : Entity_Id; | |
996ae0b0 RK |
3135 | |
3136 | begin | |
3137 | if Is_Entity_Name (N) then | |
3138 | Ent := Entity (N); | |
3139 | ||
3140 | -- An enumeration literal that was either in the source or | |
3141 | -- created as a result of static evaluation. | |
3142 | ||
3143 | if Ekind (Ent) = E_Enumeration_Literal then | |
3144 | return Enumeration_Rep (Ent); | |
3145 | ||
3146 | -- A user defined static constant | |
3147 | ||
3148 | else | |
3149 | pragma Assert (Ekind (Ent) = E_Constant); | |
3150 | return Expr_Rep_Value (Constant_Value (Ent)); | |
3151 | end if; | |
3152 | ||
3153 | -- An integer literal that was either in the source or created | |
3154 | -- as a result of static evaluation. | |
3155 | ||
3156 | elsif Kind = N_Integer_Literal then | |
3157 | return Intval (N); | |
3158 | ||
3159 | -- A real literal for a fixed-point type. This must be the fixed-point | |
3160 | -- case, either the literal is of a fixed-point type, or it is a bound | |
3161 | -- of a fixed-point type, with type universal real. In either case we | |
3162 | -- obtain the desired value from Corresponding_Integer_Value. | |
3163 | ||
3164 | elsif Kind = N_Real_Literal then | |
996ae0b0 RK |
3165 | pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N)))); |
3166 | return Corresponding_Integer_Value (N); | |
3167 | ||
07fc65c4 GB |
3168 | -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero |
3169 | ||
3170 | elsif Kind = N_Attribute_Reference | |
3171 | and then Attribute_Name (N) = Name_Null_Parameter | |
3172 | then | |
3173 | return Uint_0; | |
3174 | ||
07fc65c4 | 3175 | -- Otherwise must be character literal |
8cbb664e | 3176 | |
996ae0b0 RK |
3177 | else |
3178 | pragma Assert (Kind = N_Character_Literal); | |
3179 | Ent := Entity (N); | |
3180 | ||
3181 | -- Since Character literals of type Standard.Character don't | |
3182 | -- have any defining character literals built for them, they | |
3183 | -- do not have their Entity set, so just use their Char | |
3184 | -- code. Otherwise for user-defined character literals use | |
3185 | -- their Pos value as usual which is the same as the Rep value. | |
3186 | ||
3187 | if No (Ent) then | |
82c80734 | 3188 | return Char_Literal_Value (N); |
996ae0b0 RK |
3189 | else |
3190 | return Enumeration_Rep (Ent); | |
3191 | end if; | |
3192 | end if; | |
3193 | end Expr_Rep_Value; | |
3194 | ||
3195 | ---------------- | |
3196 | -- Expr_Value -- | |
3197 | ---------------- | |
3198 | ||
3199 | function Expr_Value (N : Node_Id) return Uint is | |
07fc65c4 GB |
3200 | Kind : constant Node_Kind := Nkind (N); |
3201 | CV_Ent : CV_Entry renames CV_Cache (Nat (N) mod CV_Cache_Size); | |
3202 | Ent : Entity_Id; | |
3203 | Val : Uint; | |
996ae0b0 RK |
3204 | |
3205 | begin | |
13f34a3f RD |
3206 | -- If already in cache, then we know it's compile time known and we can |
3207 | -- return the value that was previously stored in the cache since | |
3208 | -- compile time known values cannot change. | |
07fc65c4 GB |
3209 | |
3210 | if CV_Ent.N = N then | |
3211 | return CV_Ent.V; | |
3212 | end if; | |
3213 | ||
3214 | -- Otherwise proceed to test value | |
3215 | ||
996ae0b0 RK |
3216 | if Is_Entity_Name (N) then |
3217 | Ent := Entity (N); | |
3218 | ||
3219 | -- An enumeration literal that was either in the source or | |
3220 | -- created as a result of static evaluation. | |
3221 | ||
3222 | if Ekind (Ent) = E_Enumeration_Literal then | |
07fc65c4 | 3223 | Val := Enumeration_Pos (Ent); |
996ae0b0 RK |
3224 | |
3225 | -- A user defined static constant | |
3226 | ||
3227 | else | |
3228 | pragma Assert (Ekind (Ent) = E_Constant); | |
07fc65c4 | 3229 | Val := Expr_Value (Constant_Value (Ent)); |
996ae0b0 RK |
3230 | end if; |
3231 | ||
3232 | -- An integer literal that was either in the source or created | |
3233 | -- as a result of static evaluation. | |
3234 | ||
3235 | elsif Kind = N_Integer_Literal then | |
07fc65c4 | 3236 | Val := Intval (N); |
996ae0b0 RK |
3237 | |
3238 | -- A real literal for a fixed-point type. This must be the fixed-point | |
3239 | -- case, either the literal is of a fixed-point type, or it is a bound | |
3240 | -- of a fixed-point type, with type universal real. In either case we | |
3241 | -- obtain the desired value from Corresponding_Integer_Value. | |
3242 | ||
3243 | elsif Kind = N_Real_Literal then | |
3244 | ||
996ae0b0 | 3245 | pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N)))); |
07fc65c4 | 3246 | Val := Corresponding_Integer_Value (N); |
996ae0b0 RK |
3247 | |
3248 | -- Peculiar VMS case, if we have xxx'Null_Parameter, return zero | |
3249 | ||
3250 | elsif Kind = N_Attribute_Reference | |
3251 | and then Attribute_Name (N) = Name_Null_Parameter | |
3252 | then | |
07fc65c4 GB |
3253 | Val := Uint_0; |
3254 | ||
996ae0b0 RK |
3255 | -- Otherwise must be character literal |
3256 | ||
3257 | else | |
3258 | pragma Assert (Kind = N_Character_Literal); | |
3259 | Ent := Entity (N); | |
3260 | ||
3261 | -- Since Character literals of type Standard.Character don't | |
3262 | -- have any defining character literals built for them, they | |
3263 | -- do not have their Entity set, so just use their Char | |
3264 | -- code. Otherwise for user-defined character literals use | |
3265 | -- their Pos value as usual. | |
3266 | ||
3267 | if No (Ent) then | |
82c80734 | 3268 | Val := Char_Literal_Value (N); |
996ae0b0 | 3269 | else |
07fc65c4 | 3270 | Val := Enumeration_Pos (Ent); |
996ae0b0 RK |
3271 | end if; |
3272 | end if; | |
3273 | ||
07fc65c4 GB |
3274 | -- Come here with Val set to value to be returned, set cache |
3275 | ||
3276 | CV_Ent.N := N; | |
3277 | CV_Ent.V := Val; | |
3278 | return Val; | |
996ae0b0 RK |
3279 | end Expr_Value; |
3280 | ||
3281 | ------------------ | |
3282 | -- Expr_Value_E -- | |
3283 | ------------------ | |
3284 | ||
3285 | function Expr_Value_E (N : Node_Id) return Entity_Id is | |
3286 | Ent : constant Entity_Id := Entity (N); | |
3287 | ||
3288 | begin | |
3289 | if Ekind (Ent) = E_Enumeration_Literal then | |
3290 | return Ent; | |
3291 | else | |
3292 | pragma Assert (Ekind (Ent) = E_Constant); | |
3293 | return Expr_Value_E (Constant_Value (Ent)); | |
3294 | end if; | |
3295 | end Expr_Value_E; | |
3296 | ||
3297 | ------------------ | |
3298 | -- Expr_Value_R -- | |
3299 | ------------------ | |
3300 | ||
3301 | function Expr_Value_R (N : Node_Id) return Ureal is | |
3302 | Kind : constant Node_Kind := Nkind (N); | |
3303 | Ent : Entity_Id; | |
3304 | Expr : Node_Id; | |
3305 | ||
3306 | begin | |
3307 | if Kind = N_Real_Literal then | |
3308 | return Realval (N); | |
3309 | ||
3310 | elsif Kind = N_Identifier or else Kind = N_Expanded_Name then | |
3311 | Ent := Entity (N); | |
3312 | pragma Assert (Ekind (Ent) = E_Constant); | |
3313 | return Expr_Value_R (Constant_Value (Ent)); | |
3314 | ||
3315 | elsif Kind = N_Integer_Literal then | |
3316 | return UR_From_Uint (Expr_Value (N)); | |
3317 | ||
3318 | -- Strange case of VAX literals, which are at this stage transformed | |
3319 | -- into Vax_Type!x_To_y(IEEE_Literal). See Expand_N_Real_Literal in | |
3320 | -- Exp_Vfpt for further details. | |
3321 | ||
3322 | elsif Vax_Float (Etype (N)) | |
3323 | and then Nkind (N) = N_Unchecked_Type_Conversion | |
3324 | then | |
3325 | Expr := Expression (N); | |
3326 | ||
3327 | if Nkind (Expr) = N_Function_Call | |
3328 | and then Present (Parameter_Associations (Expr)) | |
3329 | then | |
3330 | Expr := First (Parameter_Associations (Expr)); | |
3331 | ||
3332 | if Nkind (Expr) = N_Real_Literal then | |
3333 | return Realval (Expr); | |
3334 | end if; | |
3335 | end if; | |
3336 | ||
3337 | -- Peculiar VMS case, if we have xxx'Null_Parameter, return 0.0 | |
3338 | ||
3339 | elsif Kind = N_Attribute_Reference | |
3340 | and then Attribute_Name (N) = Name_Null_Parameter | |
3341 | then | |
3342 | return Ureal_0; | |
3343 | end if; | |
3344 | ||
f3d57416 | 3345 | -- If we fall through, we have a node that cannot be interpreted |
996ae0b0 RK |
3346 | -- as a compile time constant. That is definitely an error. |
3347 | ||
3348 | raise Program_Error; | |
3349 | end Expr_Value_R; | |
3350 | ||
3351 | ------------------ | |
3352 | -- Expr_Value_S -- | |
3353 | ------------------ | |
3354 | ||
3355 | function Expr_Value_S (N : Node_Id) return Node_Id is | |
3356 | begin | |
3357 | if Nkind (N) = N_String_Literal then | |
3358 | return N; | |
3359 | else | |
3360 | pragma Assert (Ekind (Entity (N)) = E_Constant); | |
3361 | return Expr_Value_S (Constant_Value (Entity (N))); | |
3362 | end if; | |
3363 | end Expr_Value_S; | |
3364 | ||
fbf5a39b AC |
3365 | -------------------------- |
3366 | -- Flag_Non_Static_Expr -- | |
3367 | -------------------------- | |
3368 | ||
3369 | procedure Flag_Non_Static_Expr (Msg : String; Expr : Node_Id) is | |
3370 | begin | |
3371 | if Error_Posted (Expr) and then not All_Errors_Mode then | |
3372 | return; | |
3373 | else | |
3374 | Error_Msg_F (Msg, Expr); | |
3375 | Why_Not_Static (Expr); | |
3376 | end if; | |
3377 | end Flag_Non_Static_Expr; | |
3378 | ||
996ae0b0 RK |
3379 | -------------- |
3380 | -- Fold_Str -- | |
3381 | -------------- | |
3382 | ||
fbf5a39b | 3383 | procedure Fold_Str (N : Node_Id; Val : String_Id; Static : Boolean) is |
996ae0b0 RK |
3384 | Loc : constant Source_Ptr := Sloc (N); |
3385 | Typ : constant Entity_Id := Etype (N); | |
3386 | ||
3387 | begin | |
3388 | Rewrite (N, Make_String_Literal (Loc, Strval => Val)); | |
fbf5a39b AC |
3389 | |
3390 | -- We now have the literal with the right value, both the actual type | |
3391 | -- and the expected type of this literal are taken from the expression | |
3392 | -- that was evaluated. | |
3393 | ||
3394 | Analyze (N); | |
3395 | Set_Is_Static_Expression (N, Static); | |
3396 | Set_Etype (N, Typ); | |
3397 | Resolve (N); | |
996ae0b0 RK |
3398 | end Fold_Str; |
3399 | ||
3400 | --------------- | |
3401 | -- Fold_Uint -- | |
3402 | --------------- | |
3403 | ||
fbf5a39b | 3404 | procedure Fold_Uint (N : Node_Id; Val : Uint; Static : Boolean) is |
996ae0b0 | 3405 | Loc : constant Source_Ptr := Sloc (N); |
fbf5a39b AC |
3406 | Typ : Entity_Id := Etype (N); |
3407 | Ent : Entity_Id; | |
996ae0b0 RK |
3408 | |
3409 | begin | |
fbf5a39b AC |
3410 | -- If we are folding a named number, retain the entity in the |
3411 | -- literal, for ASIS use. | |
3412 | ||
3413 | if Is_Entity_Name (N) | |
3414 | and then Ekind (Entity (N)) = E_Named_Integer | |
3415 | then | |
3416 | Ent := Entity (N); | |
3417 | else | |
3418 | Ent := Empty; | |
3419 | end if; | |
3420 | ||
3421 | if Is_Private_Type (Typ) then | |
3422 | Typ := Full_View (Typ); | |
3423 | end if; | |
3424 | ||
f3d57416 | 3425 | -- For a result of type integer, substitute an N_Integer_Literal node |
996ae0b0 | 3426 | -- for the result of the compile time evaluation of the expression. |
cd2fb920 ES |
3427 | -- For ASIS use, set a link to the original named number when not in |
3428 | -- a generic context. | |
996ae0b0 | 3429 | |
fbf5a39b | 3430 | if Is_Integer_Type (Typ) then |
996ae0b0 | 3431 | Rewrite (N, Make_Integer_Literal (Loc, Val)); |
cd2fb920 | 3432 | |
fbf5a39b | 3433 | Set_Original_Entity (N, Ent); |
996ae0b0 RK |
3434 | |
3435 | -- Otherwise we have an enumeration type, and we substitute either | |
3436 | -- an N_Identifier or N_Character_Literal to represent the enumeration | |
3437 | -- literal corresponding to the given value, which must always be in | |
3438 | -- range, because appropriate tests have already been made for this. | |
3439 | ||
fbf5a39b | 3440 | else pragma Assert (Is_Enumeration_Type (Typ)); |
996ae0b0 RK |
3441 | Rewrite (N, Get_Enum_Lit_From_Pos (Etype (N), Val, Loc)); |
3442 | end if; | |
3443 | ||
3444 | -- We now have the literal with the right value, both the actual type | |
3445 | -- and the expected type of this literal are taken from the expression | |
3446 | -- that was evaluated. | |
3447 | ||
3448 | Analyze (N); | |
fbf5a39b | 3449 | Set_Is_Static_Expression (N, Static); |
996ae0b0 | 3450 | Set_Etype (N, Typ); |
fbf5a39b | 3451 | Resolve (N); |
996ae0b0 RK |
3452 | end Fold_Uint; |
3453 | ||
3454 | ---------------- | |
3455 | -- Fold_Ureal -- | |
3456 | ---------------- | |
3457 | ||
fbf5a39b | 3458 | procedure Fold_Ureal (N : Node_Id; Val : Ureal; Static : Boolean) is |
996ae0b0 RK |
3459 | Loc : constant Source_Ptr := Sloc (N); |
3460 | Typ : constant Entity_Id := Etype (N); | |
fbf5a39b | 3461 | Ent : Entity_Id; |
996ae0b0 RK |
3462 | |
3463 | begin | |
fbf5a39b AC |
3464 | -- If we are folding a named number, retain the entity in the |
3465 | -- literal, for ASIS use. | |
3466 | ||
3467 | if Is_Entity_Name (N) | |
3468 | and then Ekind (Entity (N)) = E_Named_Real | |
3469 | then | |
3470 | Ent := Entity (N); | |
3471 | else | |
3472 | Ent := Empty; | |
3473 | end if; | |
3474 | ||
996ae0b0 | 3475 | Rewrite (N, Make_Real_Literal (Loc, Realval => Val)); |
cd2fb920 | 3476 | |
5a30024a | 3477 | -- Set link to original named number, for ASIS use |
cd2fb920 | 3478 | |
fbf5a39b | 3479 | Set_Original_Entity (N, Ent); |
996ae0b0 RK |
3480 | |
3481 | -- Both the actual and expected type comes from the original expression | |
3482 | ||
fbf5a39b AC |
3483 | Analyze (N); |
3484 | Set_Is_Static_Expression (N, Static); | |
996ae0b0 | 3485 | Set_Etype (N, Typ); |
fbf5a39b | 3486 | Resolve (N); |
996ae0b0 RK |
3487 | end Fold_Ureal; |
3488 | ||
3489 | --------------- | |
3490 | -- From_Bits -- | |
3491 | --------------- | |
3492 | ||
3493 | function From_Bits (B : Bits; T : Entity_Id) return Uint is | |
3494 | V : Uint := Uint_0; | |
3495 | ||
3496 | begin | |
3497 | for J in 0 .. B'Last loop | |
3498 | if B (J) then | |
3499 | V := V + 2 ** J; | |
3500 | end if; | |
3501 | end loop; | |
3502 | ||
3503 | if Non_Binary_Modulus (T) then | |
3504 | V := V mod Modulus (T); | |
3505 | end if; | |
3506 | ||
3507 | return V; | |
3508 | end From_Bits; | |
3509 | ||
3510 | -------------------- | |
3511 | -- Get_String_Val -- | |
3512 | -------------------- | |
3513 | ||
3514 | function Get_String_Val (N : Node_Id) return Node_Id is | |
3515 | begin | |
3516 | if Nkind (N) = N_String_Literal then | |
3517 | return N; | |
3518 | ||
3519 | elsif Nkind (N) = N_Character_Literal then | |
3520 | return N; | |
3521 | ||
3522 | else | |
3523 | pragma Assert (Is_Entity_Name (N)); | |
3524 | return Get_String_Val (Constant_Value (Entity (N))); | |
3525 | end if; | |
3526 | end Get_String_Val; | |
3527 | ||
fbf5a39b AC |
3528 | ---------------- |
3529 | -- Initialize -- | |
3530 | ---------------- | |
3531 | ||
3532 | procedure Initialize is | |
3533 | begin | |
3534 | CV_Cache := (others => (Node_High_Bound, Uint_0)); | |
3535 | end Initialize; | |
3536 | ||
996ae0b0 RK |
3537 | -------------------- |
3538 | -- In_Subrange_Of -- | |
3539 | -------------------- | |
3540 | ||
3541 | function In_Subrange_Of | |
c27f2f15 RD |
3542 | (T1 : Entity_Id; |
3543 | T2 : Entity_Id; | |
3544 | Fixed_Int : Boolean := False) return Boolean | |
996ae0b0 RK |
3545 | is |
3546 | L1 : Node_Id; | |
3547 | H1 : Node_Id; | |
3548 | ||
3549 | L2 : Node_Id; | |
3550 | H2 : Node_Id; | |
3551 | ||
3552 | begin | |
3553 | if T1 = T2 or else Is_Subtype_Of (T1, T2) then | |
3554 | return True; | |
3555 | ||
3556 | -- Never in range if both types are not scalar. Don't know if this can | |
3557 | -- actually happen, but just in case. | |
3558 | ||
3559 | elsif not Is_Scalar_Type (T1) or else not Is_Scalar_Type (T1) then | |
3560 | return False; | |
3561 | ||
3562 | else | |
3563 | L1 := Type_Low_Bound (T1); | |
3564 | H1 := Type_High_Bound (T1); | |
3565 | ||
3566 | L2 := Type_Low_Bound (T2); | |
3567 | H2 := Type_High_Bound (T2); | |
3568 | ||
3569 | -- Check bounds to see if comparison possible at compile time | |
3570 | ||
c27f2f15 | 3571 | if Compile_Time_Compare (L1, L2, Assume_Valid => True) in Compare_GE |
996ae0b0 | 3572 | and then |
c27f2f15 | 3573 | Compile_Time_Compare (H1, H2, Assume_Valid => True) in Compare_LE |
996ae0b0 RK |
3574 | then |
3575 | return True; | |
3576 | end if; | |
3577 | ||
3578 | -- If bounds not comparable at compile time, then the bounds of T2 | |
3579 | -- must be compile time known or we cannot answer the query. | |
3580 | ||
3581 | if not Compile_Time_Known_Value (L2) | |
3582 | or else not Compile_Time_Known_Value (H2) | |
3583 | then | |
3584 | return False; | |
3585 | end if; | |
3586 | ||
3587 | -- If the bounds of T1 are know at compile time then use these | |
3588 | -- ones, otherwise use the bounds of the base type (which are of | |
3589 | -- course always static). | |
3590 | ||
3591 | if not Compile_Time_Known_Value (L1) then | |
3592 | L1 := Type_Low_Bound (Base_Type (T1)); | |
3593 | end if; | |
3594 | ||
3595 | if not Compile_Time_Known_Value (H1) then | |
3596 | H1 := Type_High_Bound (Base_Type (T1)); | |
3597 | end if; | |
3598 | ||
3599 | -- Fixed point types should be considered as such only if | |
3600 | -- flag Fixed_Int is set to False. | |
3601 | ||
3602 | if Is_Floating_Point_Type (T1) or else Is_Floating_Point_Type (T2) | |
3603 | or else (Is_Fixed_Point_Type (T1) and then not Fixed_Int) | |
3604 | or else (Is_Fixed_Point_Type (T2) and then not Fixed_Int) | |
3605 | then | |
3606 | return | |
3607 | Expr_Value_R (L2) <= Expr_Value_R (L1) | |
3608 | and then | |
3609 | Expr_Value_R (H2) >= Expr_Value_R (H1); | |
3610 | ||
3611 | else | |
3612 | return | |
3613 | Expr_Value (L2) <= Expr_Value (L1) | |
3614 | and then | |
3615 | Expr_Value (H2) >= Expr_Value (H1); | |
3616 | ||
3617 | end if; | |
3618 | end if; | |
3619 | ||
3620 | -- If any exception occurs, it means that we have some bug in the compiler | |
f3d57416 | 3621 | -- possibly triggered by a previous error, or by some unforeseen peculiar |
996ae0b0 RK |
3622 | -- occurrence. However, this is only an optimization attempt, so there is |
3623 | -- really no point in crashing the compiler. Instead we just decide, too | |
3624 | -- bad, we can't figure out the answer in this case after all. | |
3625 | ||
3626 | exception | |
3627 | when others => | |
3628 | ||
3629 | -- Debug flag K disables this behavior (useful for debugging) | |
3630 | ||
3631 | if Debug_Flag_K then | |
3632 | raise; | |
3633 | else | |
3634 | return False; | |
3635 | end if; | |
3636 | end In_Subrange_Of; | |
3637 | ||
3638 | ----------------- | |
3639 | -- Is_In_Range -- | |
3640 | ----------------- | |
3641 | ||
3642 | function Is_In_Range | |
c800f862 RD |
3643 | (N : Node_Id; |
3644 | Typ : Entity_Id; | |
3645 | Assume_Valid : Boolean := False; | |
3646 | Fixed_Int : Boolean := False; | |
3647 | Int_Real : Boolean := False) return Boolean | |
996ae0b0 RK |
3648 | is |
3649 | Val : Uint; | |
3650 | Valr : Ureal; | |
3651 | ||
c27f2f15 RD |
3652 | pragma Warnings (Off, Assume_Valid); |
3653 | -- For now Assume_Valid is unreferenced since the current implementation | |
3654 | -- always returns False if N is not a compile time known value, but we | |
3655 | -- keep the parameter to allow for future enhancements in which we try | |
3656 | -- to get the information in the variable case as well. | |
3657 | ||
996ae0b0 | 3658 | begin |
82c80734 | 3659 | -- Universal types have no range limits, so always in range |
996ae0b0 RK |
3660 | |
3661 | if Typ = Universal_Integer or else Typ = Universal_Real then | |
3662 | return True; | |
3663 | ||
3664 | -- Never in range if not scalar type. Don't know if this can | |
3665 | -- actually happen, but our spec allows it, so we must check! | |
3666 | ||
3667 | elsif not Is_Scalar_Type (Typ) then | |
3668 | return False; | |
3669 | ||
82c80734 | 3670 | -- Never in range unless we have a compile time known value |
996ae0b0 RK |
3671 | |
3672 | elsif not Compile_Time_Known_Value (N) then | |
3673 | return False; | |
3674 | ||
c800f862 RD |
3675 | -- General processing with a known compile time value |
3676 | ||
996ae0b0 RK |
3677 | else |
3678 | declare | |
c800f862 RD |
3679 | Lo : Node_Id; |
3680 | Hi : Node_Id; | |
3681 | LB_Known : Boolean; | |
3682 | UB_Known : Boolean; | |
996ae0b0 RK |
3683 | |
3684 | begin | |
c27f2f15 RD |
3685 | Lo := Type_Low_Bound (Typ); |
3686 | Hi := Type_High_Bound (Typ); | |
c800f862 RD |
3687 | |
3688 | LB_Known := Compile_Time_Known_Value (Lo); | |
3689 | UB_Known := Compile_Time_Known_Value (Hi); | |
3690 | ||
996ae0b0 RK |
3691 | -- Fixed point types should be considered as such only in |
3692 | -- flag Fixed_Int is set to False. | |
3693 | ||
c27f2f15 RD |
3694 | if Is_Floating_Point_Type (Typ) |
3695 | or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int) | |
996ae0b0 RK |
3696 | or else Int_Real |
3697 | then | |
3698 | Valr := Expr_Value_R (N); | |
3699 | ||
3700 | if LB_Known and then Valr >= Expr_Value_R (Lo) | |
3701 | and then UB_Known and then Valr <= Expr_Value_R (Hi) | |
3702 | then | |
3703 | return True; | |
3704 | else | |
3705 | return False; | |
3706 | end if; | |
3707 | ||
3708 | else | |
3709 | Val := Expr_Value (N); | |
3710 | ||
3711 | if LB_Known and then Val >= Expr_Value (Lo) | |
3712 | and then UB_Known and then Val <= Expr_Value (Hi) | |
3713 | then | |
3714 | return True; | |
3715 | else | |
3716 | return False; | |
3717 | end if; | |
3718 | end if; | |
3719 | end; | |
3720 | end if; | |
3721 | end Is_In_Range; | |
3722 | ||
3723 | ------------------- | |
3724 | -- Is_Null_Range -- | |
3725 | ------------------- | |
3726 | ||
3727 | function Is_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is | |
3728 | Typ : constant Entity_Id := Etype (Lo); | |
3729 | ||
3730 | begin | |
3731 | if not Compile_Time_Known_Value (Lo) | |
3732 | or else not Compile_Time_Known_Value (Hi) | |
3733 | then | |
3734 | return False; | |
3735 | end if; | |
3736 | ||
3737 | if Is_Discrete_Type (Typ) then | |
3738 | return Expr_Value (Lo) > Expr_Value (Hi); | |
3739 | ||
3740 | else | |
3741 | pragma Assert (Is_Real_Type (Typ)); | |
3742 | return Expr_Value_R (Lo) > Expr_Value_R (Hi); | |
3743 | end if; | |
3744 | end Is_Null_Range; | |
3745 | ||
3746 | ----------------------------- | |
3747 | -- Is_OK_Static_Expression -- | |
3748 | ----------------------------- | |
3749 | ||
3750 | function Is_OK_Static_Expression (N : Node_Id) return Boolean is | |
3751 | begin | |
3752 | return Is_Static_Expression (N) | |
3753 | and then not Raises_Constraint_Error (N); | |
3754 | end Is_OK_Static_Expression; | |
3755 | ||
3756 | ------------------------ | |
3757 | -- Is_OK_Static_Range -- | |
3758 | ------------------------ | |
3759 | ||
3760 | -- A static range is a range whose bounds are static expressions, or a | |
3761 | -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)). | |
3762 | -- We have already converted range attribute references, so we get the | |
3763 | -- "or" part of this rule without needing a special test. | |
3764 | ||
3765 | function Is_OK_Static_Range (N : Node_Id) return Boolean is | |
3766 | begin | |
3767 | return Is_OK_Static_Expression (Low_Bound (N)) | |
3768 | and then Is_OK_Static_Expression (High_Bound (N)); | |
3769 | end Is_OK_Static_Range; | |
3770 | ||
3771 | -------------------------- | |
3772 | -- Is_OK_Static_Subtype -- | |
3773 | -------------------------- | |
3774 | ||
3775 | -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) | |
3776 | -- where neither bound raises constraint error when evaluated. | |
3777 | ||
3778 | function Is_OK_Static_Subtype (Typ : Entity_Id) return Boolean is | |
3779 | Base_T : constant Entity_Id := Base_Type (Typ); | |
3780 | Anc_Subt : Entity_Id; | |
3781 | ||
3782 | begin | |
3783 | -- First a quick check on the non static subtype flag. As described | |
3784 | -- in further detail in Einfo, this flag is not decisive in all cases, | |
3785 | -- but if it is set, then the subtype is definitely non-static. | |
3786 | ||
3787 | if Is_Non_Static_Subtype (Typ) then | |
3788 | return False; | |
3789 | end if; | |
3790 | ||
3791 | Anc_Subt := Ancestor_Subtype (Typ); | |
3792 | ||
3793 | if Anc_Subt = Empty then | |
3794 | Anc_Subt := Base_T; | |
3795 | end if; | |
3796 | ||
3797 | if Is_Generic_Type (Root_Type (Base_T)) | |
3798 | or else Is_Generic_Actual_Type (Base_T) | |
3799 | then | |
3800 | return False; | |
3801 | ||
3802 | -- String types | |
3803 | ||
3804 | elsif Is_String_Type (Typ) then | |
3805 | return | |
3806 | Ekind (Typ) = E_String_Literal_Subtype | |
3807 | or else | |
3808 | (Is_OK_Static_Subtype (Component_Type (Typ)) | |
3809 | and then Is_OK_Static_Subtype (Etype (First_Index (Typ)))); | |
3810 | ||
3811 | -- Scalar types | |
3812 | ||
3813 | elsif Is_Scalar_Type (Typ) then | |
3814 | if Base_T = Typ then | |
3815 | return True; | |
3816 | ||
3817 | else | |
3818 | -- Scalar_Range (Typ) might be an N_Subtype_Indication, so | |
3819 | -- use Get_Type_Low,High_Bound. | |
3820 | ||
3821 | return Is_OK_Static_Subtype (Anc_Subt) | |
3822 | and then Is_OK_Static_Expression (Type_Low_Bound (Typ)) | |
3823 | and then Is_OK_Static_Expression (Type_High_Bound (Typ)); | |
3824 | end if; | |
3825 | ||
3826 | -- Types other than string and scalar types are never static | |
3827 | ||
3828 | else | |
3829 | return False; | |
3830 | end if; | |
3831 | end Is_OK_Static_Subtype; | |
3832 | ||
3833 | --------------------- | |
3834 | -- Is_Out_Of_Range -- | |
3835 | --------------------- | |
3836 | ||
3837 | function Is_Out_Of_Range | |
1c7717c3 AC |
3838 | (N : Node_Id; |
3839 | Typ : Entity_Id; | |
c800f862 | 3840 | Assume_Valid : Boolean := False; |
1c7717c3 AC |
3841 | Fixed_Int : Boolean := False; |
3842 | Int_Real : Boolean := False) return Boolean | |
996ae0b0 RK |
3843 | is |
3844 | Val : Uint; | |
3845 | Valr : Ureal; | |
3846 | ||
c27f2f15 RD |
3847 | pragma Warnings (Off, Assume_Valid); |
3848 | -- For now Assume_Valid is unreferenced since the current implementation | |
3849 | -- always returns False if N is not a compile time known value, but we | |
3850 | -- keep the parameter to allow for future enhancements in which we try | |
3851 | -- to get the information in the variable case as well. | |
3852 | ||
996ae0b0 | 3853 | begin |
82c80734 | 3854 | -- Universal types have no range limits, so always in range |
996ae0b0 RK |
3855 | |
3856 | if Typ = Universal_Integer or else Typ = Universal_Real then | |
3857 | return False; | |
3858 | ||
3859 | -- Never out of range if not scalar type. Don't know if this can | |
3860 | -- actually happen, but our spec allows it, so we must check! | |
3861 | ||
3862 | elsif not Is_Scalar_Type (Typ) then | |
3863 | return False; | |
3864 | ||
3865 | -- Never out of range if this is a generic type, since the bounds | |
3866 | -- of generic types are junk. Note that if we only checked for | |
3867 | -- static expressions (instead of compile time known values) below, | |
3868 | -- we would not need this check, because values of a generic type | |
3869 | -- can never be static, but they can be known at compile time. | |
3870 | ||
3871 | elsif Is_Generic_Type (Typ) then | |
3872 | return False; | |
3873 | ||
fbf5a39b | 3874 | -- Never out of range unless we have a compile time known value |
996ae0b0 RK |
3875 | |
3876 | elsif not Compile_Time_Known_Value (N) then | |
3877 | return False; | |
3878 | ||
3879 | else | |
3880 | declare | |
c800f862 RD |
3881 | Lo : Node_Id; |
3882 | Hi : Node_Id; | |
3883 | LB_Known : Boolean; | |
3884 | UB_Known : Boolean; | |
996ae0b0 RK |
3885 | |
3886 | begin | |
c27f2f15 RD |
3887 | Lo := Type_Low_Bound (Typ); |
3888 | Hi := Type_High_Bound (Typ); | |
c800f862 RD |
3889 | |
3890 | LB_Known := Compile_Time_Known_Value (Lo); | |
3891 | UB_Known := Compile_Time_Known_Value (Hi); | |
3892 | ||
996ae0b0 RK |
3893 | -- Real types (note that fixed-point types are not treated |
3894 | -- as being of a real type if the flag Fixed_Int is set, | |
3895 | -- since in that case they are regarded as integer types). | |
3896 | ||
c27f2f15 RD |
3897 | if Is_Floating_Point_Type (Typ) |
3898 | or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int) | |
996ae0b0 RK |
3899 | or else Int_Real |
3900 | then | |
3901 | Valr := Expr_Value_R (N); | |
3902 | ||
3903 | if LB_Known and then Valr < Expr_Value_R (Lo) then | |
3904 | return True; | |
3905 | ||
3906 | elsif UB_Known and then Expr_Value_R (Hi) < Valr then | |
3907 | return True; | |
3908 | ||
3909 | else | |
3910 | return False; | |
3911 | end if; | |
3912 | ||
3913 | else | |
3914 | Val := Expr_Value (N); | |
3915 | ||
3916 | if LB_Known and then Val < Expr_Value (Lo) then | |
3917 | return True; | |
3918 | ||
3919 | elsif UB_Known and then Expr_Value (Hi) < Val then | |
3920 | return True; | |
3921 | ||
3922 | else | |
3923 | return False; | |
3924 | end if; | |
3925 | end if; | |
3926 | end; | |
3927 | end if; | |
3928 | end Is_Out_Of_Range; | |
3929 | ||
3930 | --------------------- | |
3931 | -- Is_Static_Range -- | |
3932 | --------------------- | |
3933 | ||
3934 | -- A static range is a range whose bounds are static expressions, or a | |
3935 | -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)). | |
3936 | -- We have already converted range attribute references, so we get the | |
3937 | -- "or" part of this rule without needing a special test. | |
3938 | ||
3939 | function Is_Static_Range (N : Node_Id) return Boolean is | |
3940 | begin | |
3941 | return Is_Static_Expression (Low_Bound (N)) | |
3942 | and then Is_Static_Expression (High_Bound (N)); | |
3943 | end Is_Static_Range; | |
3944 | ||
3945 | ----------------------- | |
3946 | -- Is_Static_Subtype -- | |
3947 | ----------------------- | |
3948 | ||
82c80734 | 3949 | -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) |
996ae0b0 RK |
3950 | |
3951 | function Is_Static_Subtype (Typ : Entity_Id) return Boolean is | |
3952 | Base_T : constant Entity_Id := Base_Type (Typ); | |
3953 | Anc_Subt : Entity_Id; | |
3954 | ||
3955 | begin | |
3956 | -- First a quick check on the non static subtype flag. As described | |
3957 | -- in further detail in Einfo, this flag is not decisive in all cases, | |
3958 | -- but if it is set, then the subtype is definitely non-static. | |
3959 | ||
3960 | if Is_Non_Static_Subtype (Typ) then | |
3961 | return False; | |
3962 | end if; | |
3963 | ||
3964 | Anc_Subt := Ancestor_Subtype (Typ); | |
3965 | ||
3966 | if Anc_Subt = Empty then | |
3967 | Anc_Subt := Base_T; | |
3968 | end if; | |
3969 | ||
3970 | if Is_Generic_Type (Root_Type (Base_T)) | |
3971 | or else Is_Generic_Actual_Type (Base_T) | |
3972 | then | |
3973 | return False; | |
3974 | ||
3975 | -- String types | |
3976 | ||
3977 | elsif Is_String_Type (Typ) then | |
3978 | return | |
3979 | Ekind (Typ) = E_String_Literal_Subtype | |
3980 | or else | |
3981 | (Is_Static_Subtype (Component_Type (Typ)) | |
3982 | and then Is_Static_Subtype (Etype (First_Index (Typ)))); | |
3983 | ||
3984 | -- Scalar types | |
3985 | ||
3986 | elsif Is_Scalar_Type (Typ) then | |
3987 | if Base_T = Typ then | |
3988 | return True; | |
3989 | ||
3990 | else | |
3991 | return Is_Static_Subtype (Anc_Subt) | |
3992 | and then Is_Static_Expression (Type_Low_Bound (Typ)) | |
3993 | and then Is_Static_Expression (Type_High_Bound (Typ)); | |
3994 | end if; | |
3995 | ||
3996 | -- Types other than string and scalar types are never static | |
3997 | ||
3998 | else | |
3999 | return False; | |
4000 | end if; | |
4001 | end Is_Static_Subtype; | |
4002 | ||
4003 | -------------------- | |
4004 | -- Not_Null_Range -- | |
4005 | -------------------- | |
4006 | ||
4007 | function Not_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is | |
4008 | Typ : constant Entity_Id := Etype (Lo); | |
4009 | ||
4010 | begin | |
4011 | if not Compile_Time_Known_Value (Lo) | |
4012 | or else not Compile_Time_Known_Value (Hi) | |
4013 | then | |
4014 | return False; | |
4015 | end if; | |
4016 | ||
4017 | if Is_Discrete_Type (Typ) then | |
4018 | return Expr_Value (Lo) <= Expr_Value (Hi); | |
4019 | ||
4020 | else | |
4021 | pragma Assert (Is_Real_Type (Typ)); | |
4022 | ||
4023 | return Expr_Value_R (Lo) <= Expr_Value_R (Hi); | |
4024 | end if; | |
4025 | end Not_Null_Range; | |
4026 | ||
4027 | ------------- | |
4028 | -- OK_Bits -- | |
4029 | ------------- | |
4030 | ||
4031 | function OK_Bits (N : Node_Id; Bits : Uint) return Boolean is | |
4032 | begin | |
4033 | -- We allow a maximum of 500,000 bits which seems a reasonable limit | |
4034 | ||
4035 | if Bits < 500_000 then | |
4036 | return True; | |
4037 | ||
4038 | else | |
4039 | Error_Msg_N ("static value too large, capacity exceeded", N); | |
4040 | return False; | |
4041 | end if; | |
4042 | end OK_Bits; | |
4043 | ||
4044 | ------------------ | |
4045 | -- Out_Of_Range -- | |
4046 | ------------------ | |
4047 | ||
4048 | procedure Out_Of_Range (N : Node_Id) is | |
4049 | begin | |
4050 | -- If we have the static expression case, then this is an illegality | |
4051 | -- in Ada 95 mode, except that in an instance, we never generate an | |
4052 | -- error (if the error is legitimate, it was already diagnosed in | |
4053 | -- the template). The expression to compute the length of a packed | |
4054 | -- array is attached to the array type itself, and deserves a separate | |
4055 | -- message. | |
4056 | ||
4057 | if Is_Static_Expression (N) | |
4058 | and then not In_Instance | |
fbf5a39b | 4059 | and then not In_Inlined_Body |
0ab80019 | 4060 | and then Ada_Version >= Ada_95 |
996ae0b0 | 4061 | then |
996ae0b0 RK |
4062 | if Nkind (Parent (N)) = N_Defining_Identifier |
4063 | and then Is_Array_Type (Parent (N)) | |
4064 | and then Present (Packed_Array_Type (Parent (N))) | |
4065 | and then Present (First_Rep_Item (Parent (N))) | |
4066 | then | |
4067 | Error_Msg_N | |
4068 | ("length of packed array must not exceed Integer''Last", | |
4069 | First_Rep_Item (Parent (N))); | |
4070 | Rewrite (N, Make_Integer_Literal (Sloc (N), Uint_1)); | |
4071 | ||
4072 | else | |
4073 | Apply_Compile_Time_Constraint_Error | |
07fc65c4 | 4074 | (N, "value not in range of}", CE_Range_Check_Failed); |
996ae0b0 RK |
4075 | end if; |
4076 | ||
4077 | -- Here we generate a warning for the Ada 83 case, or when we are | |
4078 | -- in an instance, or when we have a non-static expression case. | |
4079 | ||
4080 | else | |
996ae0b0 | 4081 | Apply_Compile_Time_Constraint_Error |
07fc65c4 | 4082 | (N, "value not in range of}?", CE_Range_Check_Failed); |
996ae0b0 RK |
4083 | end if; |
4084 | end Out_Of_Range; | |
4085 | ||
4086 | ------------------------- | |
4087 | -- Rewrite_In_Raise_CE -- | |
4088 | ------------------------- | |
4089 | ||
4090 | procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id) is | |
4091 | Typ : constant Entity_Id := Etype (N); | |
4092 | ||
4093 | begin | |
4094 | -- If we want to raise CE in the condition of a raise_CE node | |
4095 | -- we may as well get rid of the condition | |
4096 | ||
4097 | if Present (Parent (N)) | |
4098 | and then Nkind (Parent (N)) = N_Raise_Constraint_Error | |
4099 | then | |
4100 | Set_Condition (Parent (N), Empty); | |
4101 | ||
4102 | -- If the expression raising CE is a N_Raise_CE node, we can use | |
4103 | -- that one. We just preserve the type of the context | |
4104 | ||
4105 | elsif Nkind (Exp) = N_Raise_Constraint_Error then | |
4106 | Rewrite (N, Exp); | |
4107 | Set_Etype (N, Typ); | |
4108 | ||
4109 | -- We have to build an explicit raise_ce node | |
4110 | ||
4111 | else | |
07fc65c4 GB |
4112 | Rewrite (N, |
4113 | Make_Raise_Constraint_Error (Sloc (Exp), | |
4114 | Reason => CE_Range_Check_Failed)); | |
996ae0b0 RK |
4115 | Set_Raises_Constraint_Error (N); |
4116 | Set_Etype (N, Typ); | |
4117 | end if; | |
4118 | end Rewrite_In_Raise_CE; | |
4119 | ||
4120 | --------------------- | |
4121 | -- String_Type_Len -- | |
4122 | --------------------- | |
4123 | ||
4124 | function String_Type_Len (Stype : Entity_Id) return Uint is | |
4125 | NT : constant Entity_Id := Etype (First_Index (Stype)); | |
4126 | T : Entity_Id; | |
4127 | ||
4128 | begin | |
4129 | if Is_OK_Static_Subtype (NT) then | |
4130 | T := NT; | |
4131 | else | |
4132 | T := Base_Type (NT); | |
4133 | end if; | |
4134 | ||
4135 | return Expr_Value (Type_High_Bound (T)) - | |
4136 | Expr_Value (Type_Low_Bound (T)) + 1; | |
4137 | end String_Type_Len; | |
4138 | ||
4139 | ------------------------------------ | |
4140 | -- Subtypes_Statically_Compatible -- | |
4141 | ------------------------------------ | |
4142 | ||
4143 | function Subtypes_Statically_Compatible | |
f44fe430 RD |
4144 | (T1 : Entity_Id; |
4145 | T2 : Entity_Id) return Boolean | |
996ae0b0 RK |
4146 | is |
4147 | begin | |
4148 | if Is_Scalar_Type (T1) then | |
4149 | ||
4150 | -- Definitely compatible if we match | |
4151 | ||
4152 | if Subtypes_Statically_Match (T1, T2) then | |
4153 | return True; | |
4154 | ||
4155 | -- If either subtype is nonstatic then they're not compatible | |
4156 | ||
4157 | elsif not Is_Static_Subtype (T1) | |
4158 | or else not Is_Static_Subtype (T2) | |
4159 | then | |
4160 | return False; | |
4161 | ||
4162 | -- If either type has constraint error bounds, then consider that | |
4163 | -- they match to avoid junk cascaded errors here. | |
4164 | ||
4165 | elsif not Is_OK_Static_Subtype (T1) | |
4166 | or else not Is_OK_Static_Subtype (T2) | |
4167 | then | |
4168 | return True; | |
4169 | ||
4170 | -- Base types must match, but we don't check that (should | |
4171 | -- we???) but we do at least check that both types are | |
4172 | -- real, or both types are not real. | |
4173 | ||
fbf5a39b | 4174 | elsif Is_Real_Type (T1) /= Is_Real_Type (T2) then |
996ae0b0 RK |
4175 | return False; |
4176 | ||
4177 | -- Here we check the bounds | |
4178 | ||
4179 | else | |
4180 | declare | |
4181 | LB1 : constant Node_Id := Type_Low_Bound (T1); | |
4182 | HB1 : constant Node_Id := Type_High_Bound (T1); | |
4183 | LB2 : constant Node_Id := Type_Low_Bound (T2); | |
4184 | HB2 : constant Node_Id := Type_High_Bound (T2); | |
4185 | ||
4186 | begin | |
4187 | if Is_Real_Type (T1) then | |
4188 | return | |
4189 | (Expr_Value_R (LB1) > Expr_Value_R (HB1)) | |
4190 | or else | |
4191 | (Expr_Value_R (LB2) <= Expr_Value_R (LB1) | |
4192 | and then | |
4193 | Expr_Value_R (HB1) <= Expr_Value_R (HB2)); | |
4194 | ||
4195 | else | |
4196 | return | |
4197 | (Expr_Value (LB1) > Expr_Value (HB1)) | |
4198 | or else | |
4199 | (Expr_Value (LB2) <= Expr_Value (LB1) | |
4200 | and then | |
4201 | Expr_Value (HB1) <= Expr_Value (HB2)); | |
4202 | end if; | |
4203 | end; | |
4204 | end if; | |
4205 | ||
4206 | elsif Is_Access_Type (T1) then | |
4207 | return not Is_Constrained (T2) | |
4208 | or else Subtypes_Statically_Match | |
4209 | (Designated_Type (T1), Designated_Type (T2)); | |
4210 | ||
4211 | else | |
4212 | return (Is_Composite_Type (T1) and then not Is_Constrained (T2)) | |
4213 | or else Subtypes_Statically_Match (T1, T2); | |
4214 | end if; | |
4215 | end Subtypes_Statically_Compatible; | |
4216 | ||
4217 | ------------------------------- | |
4218 | -- Subtypes_Statically_Match -- | |
4219 | ------------------------------- | |
4220 | ||
4221 | -- Subtypes statically match if they have statically matching constraints | |
4222 | -- (RM 4.9.1(2)). Constraints statically match if there are none, or if | |
4223 | -- they are the same identical constraint, or if they are static and the | |
4224 | -- values match (RM 4.9.1(1)). | |
4225 | ||
4226 | function Subtypes_Statically_Match (T1, T2 : Entity_Id) return Boolean is | |
4227 | begin | |
4228 | -- A type always statically matches itself | |
4229 | ||
4230 | if T1 = T2 then | |
4231 | return True; | |
4232 | ||
4233 | -- Scalar types | |
4234 | ||
4235 | elsif Is_Scalar_Type (T1) then | |
4236 | ||
4237 | -- Base types must be the same | |
4238 | ||
4239 | if Base_Type (T1) /= Base_Type (T2) then | |
4240 | return False; | |
4241 | end if; | |
4242 | ||
4243 | -- A constrained numeric subtype never matches an unconstrained | |
4244 | -- subtype, i.e. both types must be constrained or unconstrained. | |
4245 | ||
4246 | -- To understand the requirement for this test, see RM 4.9.1(1). | |
4247 | -- As is made clear in RM 3.5.4(11), type Integer, for example | |
4248 | -- is a constrained subtype with constraint bounds matching the | |
f3d57416 | 4249 | -- bounds of its corresponding unconstrained base type. In this |
996ae0b0 RK |
4250 | -- situation, Integer and Integer'Base do not statically match, |
4251 | -- even though they have the same bounds. | |
4252 | ||
4253 | -- We only apply this test to types in Standard and types that | |
4254 | -- appear in user programs. That way, we do not have to be | |
4255 | -- too careful about setting Is_Constrained right for itypes. | |
4256 | ||
4257 | if Is_Numeric_Type (T1) | |
4258 | and then (Is_Constrained (T1) /= Is_Constrained (T2)) | |
4259 | and then (Scope (T1) = Standard_Standard | |
4260 | or else Comes_From_Source (T1)) | |
4261 | and then (Scope (T2) = Standard_Standard | |
4262 | or else Comes_From_Source (T2)) | |
4263 | then | |
4264 | return False; | |
82c80734 RD |
4265 | |
4266 | -- A generic scalar type does not statically match its base | |
4267 | -- type (AI-311). In this case we make sure that the formals, | |
4268 | -- which are first subtypes of their bases, are constrained. | |
4269 | ||
4270 | elsif Is_Generic_Type (T1) | |
4271 | and then Is_Generic_Type (T2) | |
4272 | and then (Is_Constrained (T1) /= Is_Constrained (T2)) | |
4273 | then | |
4274 | return False; | |
996ae0b0 RK |
4275 | end if; |
4276 | ||
4277 | -- If there was an error in either range, then just assume | |
4278 | -- the types statically match to avoid further junk errors | |
4279 | ||
4280 | if Error_Posted (Scalar_Range (T1)) | |
4281 | or else | |
4282 | Error_Posted (Scalar_Range (T2)) | |
4283 | then | |
4284 | return True; | |
4285 | end if; | |
4286 | ||
4287 | -- Otherwise both types have bound that can be compared | |
4288 | ||
4289 | declare | |
4290 | LB1 : constant Node_Id := Type_Low_Bound (T1); | |
4291 | HB1 : constant Node_Id := Type_High_Bound (T1); | |
4292 | LB2 : constant Node_Id := Type_Low_Bound (T2); | |
4293 | HB2 : constant Node_Id := Type_High_Bound (T2); | |
4294 | ||
4295 | begin | |
4296 | -- If the bounds are the same tree node, then match | |
4297 | ||
4298 | if LB1 = LB2 and then HB1 = HB2 then | |
4299 | return True; | |
4300 | ||
4301 | -- Otherwise bounds must be static and identical value | |
4302 | ||
4303 | else | |
4304 | if not Is_Static_Subtype (T1) | |
4305 | or else not Is_Static_Subtype (T2) | |
4306 | then | |
4307 | return False; | |
4308 | ||
4309 | -- If either type has constraint error bounds, then say | |
4310 | -- that they match to avoid junk cascaded errors here. | |
4311 | ||
4312 | elsif not Is_OK_Static_Subtype (T1) | |
4313 | or else not Is_OK_Static_Subtype (T2) | |
4314 | then | |
4315 | return True; | |
4316 | ||
4317 | elsif Is_Real_Type (T1) then | |
4318 | return | |
4319 | (Expr_Value_R (LB1) = Expr_Value_R (LB2)) | |
4320 | and then | |
4321 | (Expr_Value_R (HB1) = Expr_Value_R (HB2)); | |
4322 | ||
4323 | else | |
4324 | return | |
4325 | Expr_Value (LB1) = Expr_Value (LB2) | |
4326 | and then | |
4327 | Expr_Value (HB1) = Expr_Value (HB2); | |
4328 | end if; | |
4329 | end if; | |
4330 | end; | |
4331 | ||
4332 | -- Type with discriminants | |
4333 | ||
4334 | elsif Has_Discriminants (T1) or else Has_Discriminants (T2) then | |
6eaf4095 | 4335 | |
c2bf339e GD |
4336 | -- Because of view exchanges in multiple instantiations, conformance |
4337 | -- checking might try to match a partial view of a type with no | |
4338 | -- discriminants with a full view that has defaulted discriminants. | |
4339 | -- In such a case, use the discriminant constraint of the full view, | |
4340 | -- which must exist because we know that the two subtypes have the | |
4341 | -- same base type. | |
6eaf4095 | 4342 | |
996ae0b0 | 4343 | if Has_Discriminants (T1) /= Has_Discriminants (T2) then |
c2bf339e GD |
4344 | if In_Instance then |
4345 | if Is_Private_Type (T2) | |
4346 | and then Present (Full_View (T2)) | |
4347 | and then Has_Discriminants (Full_View (T2)) | |
4348 | then | |
4349 | return Subtypes_Statically_Match (T1, Full_View (T2)); | |
4350 | ||
4351 | elsif Is_Private_Type (T1) | |
4352 | and then Present (Full_View (T1)) | |
4353 | and then Has_Discriminants (Full_View (T1)) | |
4354 | then | |
4355 | return Subtypes_Statically_Match (Full_View (T1), T2); | |
4356 | ||
4357 | else | |
4358 | return False; | |
4359 | end if; | |
6eaf4095 ES |
4360 | else |
4361 | return False; | |
4362 | end if; | |
996ae0b0 RK |
4363 | end if; |
4364 | ||
4365 | declare | |
4366 | DL1 : constant Elist_Id := Discriminant_Constraint (T1); | |
4367 | DL2 : constant Elist_Id := Discriminant_Constraint (T2); | |
4368 | ||
13f34a3f RD |
4369 | DA1 : Elmt_Id; |
4370 | DA2 : Elmt_Id; | |
996ae0b0 RK |
4371 | |
4372 | begin | |
4373 | if DL1 = DL2 then | |
4374 | return True; | |
996ae0b0 RK |
4375 | elsif Is_Constrained (T1) /= Is_Constrained (T2) then |
4376 | return False; | |
4377 | end if; | |
4378 | ||
13f34a3f | 4379 | -- Now loop through the discriminant constraints |
996ae0b0 | 4380 | |
13f34a3f RD |
4381 | -- Note: the guard here seems necessary, since it is possible at |
4382 | -- least for DL1 to be No_Elist. Not clear this is reasonable ??? | |
996ae0b0 | 4383 | |
13f34a3f RD |
4384 | if Present (DL1) and then Present (DL2) then |
4385 | DA1 := First_Elmt (DL1); | |
4386 | DA2 := First_Elmt (DL2); | |
4387 | while Present (DA1) loop | |
4388 | declare | |
4389 | Expr1 : constant Node_Id := Node (DA1); | |
4390 | Expr2 : constant Node_Id := Node (DA2); | |
996ae0b0 | 4391 | |
13f34a3f RD |
4392 | begin |
4393 | if not Is_Static_Expression (Expr1) | |
4394 | or else not Is_Static_Expression (Expr2) | |
4395 | then | |
4396 | return False; | |
996ae0b0 | 4397 | |
13f34a3f RD |
4398 | -- If either expression raised a constraint error, |
4399 | -- consider the expressions as matching, since this | |
4400 | -- helps to prevent cascading errors. | |
4401 | ||
4402 | elsif Raises_Constraint_Error (Expr1) | |
4403 | or else Raises_Constraint_Error (Expr2) | |
4404 | then | |
4405 | null; | |
4406 | ||
4407 | elsif Expr_Value (Expr1) /= Expr_Value (Expr2) then | |
4408 | return False; | |
4409 | end if; | |
4410 | end; | |
996ae0b0 | 4411 | |
13f34a3f RD |
4412 | Next_Elmt (DA1); |
4413 | Next_Elmt (DA2); | |
4414 | end loop; | |
4415 | end if; | |
996ae0b0 RK |
4416 | end; |
4417 | ||
4418 | return True; | |
4419 | ||
82c80734 | 4420 | -- A definite type does not match an indefinite or classwide type |
0356699b RD |
4421 | -- However, a generic type with unknown discriminants may be |
4422 | -- instantiated with a type with no discriminants, and conformance | |
4423 | -- checking on an inherited operation may compare the actual with | |
4424 | -- the subtype that renames it in the instance. | |
996ae0b0 RK |
4425 | |
4426 | elsif | |
4427 | Has_Unknown_Discriminants (T1) /= Has_Unknown_Discriminants (T2) | |
4428 | then | |
7a3f77d2 AC |
4429 | return |
4430 | Is_Generic_Actual_Type (T1) or else Is_Generic_Actual_Type (T2); | |
996ae0b0 RK |
4431 | |
4432 | -- Array type | |
4433 | ||
4434 | elsif Is_Array_Type (T1) then | |
4435 | ||
4436 | -- If either subtype is unconstrained then both must be, | |
4437 | -- and if both are unconstrained then no further checking | |
4438 | -- is needed. | |
4439 | ||
4440 | if not Is_Constrained (T1) or else not Is_Constrained (T2) then | |
4441 | return not (Is_Constrained (T1) or else Is_Constrained (T2)); | |
4442 | end if; | |
4443 | ||
4444 | -- Both subtypes are constrained, so check that the index | |
4445 | -- subtypes statically match. | |
4446 | ||
4447 | declare | |
4448 | Index1 : Node_Id := First_Index (T1); | |
4449 | Index2 : Node_Id := First_Index (T2); | |
4450 | ||
4451 | begin | |
4452 | while Present (Index1) loop | |
4453 | if not | |
4454 | Subtypes_Statically_Match (Etype (Index1), Etype (Index2)) | |
4455 | then | |
4456 | return False; | |
4457 | end if; | |
4458 | ||
4459 | Next_Index (Index1); | |
4460 | Next_Index (Index2); | |
4461 | end loop; | |
4462 | ||
4463 | return True; | |
4464 | end; | |
4465 | ||
4466 | elsif Is_Access_Type (T1) then | |
b5bd964f ES |
4467 | if Can_Never_Be_Null (T1) /= Can_Never_Be_Null (T2) then |
4468 | return False; | |
4469 | ||
7a3f77d2 AC |
4470 | elsif Ekind (T1) = E_Access_Subprogram_Type |
4471 | or else Ekind (T1) = E_Anonymous_Access_Subprogram_Type | |
4472 | then | |
b5bd964f ES |
4473 | return |
4474 | Subtype_Conformant | |
4475 | (Designated_Type (T1), | |
bb98fe75 | 4476 | Designated_Type (T2)); |
b5bd964f ES |
4477 | else |
4478 | return | |
4479 | Subtypes_Statically_Match | |
4480 | (Designated_Type (T1), | |
4481 | Designated_Type (T2)) | |
4482 | and then Is_Access_Constant (T1) = Is_Access_Constant (T2); | |
4483 | end if; | |
996ae0b0 RK |
4484 | |
4485 | -- All other types definitely match | |
4486 | ||
4487 | else | |
4488 | return True; | |
4489 | end if; | |
4490 | end Subtypes_Statically_Match; | |
4491 | ||
4492 | ---------- | |
4493 | -- Test -- | |
4494 | ---------- | |
4495 | ||
4496 | function Test (Cond : Boolean) return Uint is | |
4497 | begin | |
4498 | if Cond then | |
4499 | return Uint_1; | |
4500 | else | |
4501 | return Uint_0; | |
4502 | end if; | |
4503 | end Test; | |
4504 | ||
4505 | --------------------------------- | |
4506 | -- Test_Expression_Is_Foldable -- | |
4507 | --------------------------------- | |
4508 | ||
4509 | -- One operand case | |
4510 | ||
4511 | procedure Test_Expression_Is_Foldable | |
4512 | (N : Node_Id; | |
4513 | Op1 : Node_Id; | |
4514 | Stat : out Boolean; | |
4515 | Fold : out Boolean) | |
4516 | is | |
4517 | begin | |
4518 | Stat := False; | |
0356699b RD |
4519 | Fold := False; |
4520 | ||
4521 | if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then | |
4522 | return; | |
4523 | end if; | |
996ae0b0 RK |
4524 | |
4525 | -- If operand is Any_Type, just propagate to result and do not | |
4526 | -- try to fold, this prevents cascaded errors. | |
4527 | ||
4528 | if Etype (Op1) = Any_Type then | |
4529 | Set_Etype (N, Any_Type); | |
996ae0b0 RK |
4530 | return; |
4531 | ||
4532 | -- If operand raises constraint error, then replace node N with the | |
4533 | -- raise constraint error node, and we are obviously not foldable. | |
4534 | -- Note that this replacement inherits the Is_Static_Expression flag | |
4535 | -- from the operand. | |
4536 | ||
4537 | elsif Raises_Constraint_Error (Op1) then | |
4538 | Rewrite_In_Raise_CE (N, Op1); | |
996ae0b0 RK |
4539 | return; |
4540 | ||
4541 | -- If the operand is not static, then the result is not static, and | |
4542 | -- all we have to do is to check the operand since it is now known | |
4543 | -- to appear in a non-static context. | |
4544 | ||
4545 | elsif not Is_Static_Expression (Op1) then | |
4546 | Check_Non_Static_Context (Op1); | |
4547 | Fold := Compile_Time_Known_Value (Op1); | |
4548 | return; | |
4549 | ||
4550 | -- An expression of a formal modular type is not foldable because | |
4551 | -- the modulus is unknown. | |
4552 | ||
4553 | elsif Is_Modular_Integer_Type (Etype (Op1)) | |
4554 | and then Is_Generic_Type (Etype (Op1)) | |
4555 | then | |
4556 | Check_Non_Static_Context (Op1); | |
996ae0b0 RK |
4557 | return; |
4558 | ||
4559 | -- Here we have the case of an operand whose type is OK, which is | |
4560 | -- static, and which does not raise constraint error, we can fold. | |
4561 | ||
4562 | else | |
4563 | Set_Is_Static_Expression (N); | |
4564 | Fold := True; | |
4565 | Stat := True; | |
4566 | end if; | |
4567 | end Test_Expression_Is_Foldable; | |
4568 | ||
4569 | -- Two operand case | |
4570 | ||
4571 | procedure Test_Expression_Is_Foldable | |
4572 | (N : Node_Id; | |
4573 | Op1 : Node_Id; | |
4574 | Op2 : Node_Id; | |
4575 | Stat : out Boolean; | |
4576 | Fold : out Boolean) | |
4577 | is | |
4578 | Rstat : constant Boolean := Is_Static_Expression (Op1) | |
4579 | and then Is_Static_Expression (Op2); | |
4580 | ||
4581 | begin | |
4582 | Stat := False; | |
0356699b RD |
4583 | Fold := False; |
4584 | ||
4585 | if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then | |
4586 | return; | |
4587 | end if; | |
996ae0b0 RK |
4588 | |
4589 | -- If either operand is Any_Type, just propagate to result and | |
4590 | -- do not try to fold, this prevents cascaded errors. | |
4591 | ||
4592 | if Etype (Op1) = Any_Type or else Etype (Op2) = Any_Type then | |
4593 | Set_Etype (N, Any_Type); | |
996ae0b0 RK |
4594 | return; |
4595 | ||
4596 | -- If left operand raises constraint error, then replace node N with | |
4597 | -- the raise constraint error node, and we are obviously not foldable. | |
4598 | -- Is_Static_Expression is set from the two operands in the normal way, | |
4599 | -- and we check the right operand if it is in a non-static context. | |
4600 | ||
4601 | elsif Raises_Constraint_Error (Op1) then | |
4602 | if not Rstat then | |
4603 | Check_Non_Static_Context (Op2); | |
4604 | end if; | |
4605 | ||
4606 | Rewrite_In_Raise_CE (N, Op1); | |
4607 | Set_Is_Static_Expression (N, Rstat); | |
996ae0b0 RK |
4608 | return; |
4609 | ||
4610 | -- Similar processing for the case of the right operand. Note that | |
4611 | -- we don't use this routine for the short-circuit case, so we do | |
4612 | -- not have to worry about that special case here. | |
4613 | ||
4614 | elsif Raises_Constraint_Error (Op2) then | |
4615 | if not Rstat then | |
4616 | Check_Non_Static_Context (Op1); | |
4617 | end if; | |
4618 | ||
4619 | Rewrite_In_Raise_CE (N, Op2); | |
4620 | Set_Is_Static_Expression (N, Rstat); | |
996ae0b0 RK |
4621 | return; |
4622 | ||
82c80734 | 4623 | -- Exclude expressions of a generic modular type, as above |
996ae0b0 RK |
4624 | |
4625 | elsif Is_Modular_Integer_Type (Etype (Op1)) | |
4626 | and then Is_Generic_Type (Etype (Op1)) | |
4627 | then | |
4628 | Check_Non_Static_Context (Op1); | |
996ae0b0 RK |
4629 | return; |
4630 | ||
4631 | -- If result is not static, then check non-static contexts on operands | |
4632 | -- since one of them may be static and the other one may not be static | |
4633 | ||
4634 | elsif not Rstat then | |
4635 | Check_Non_Static_Context (Op1); | |
4636 | Check_Non_Static_Context (Op2); | |
4637 | Fold := Compile_Time_Known_Value (Op1) | |
4638 | and then Compile_Time_Known_Value (Op2); | |
4639 | return; | |
4640 | ||
4641 | -- Else result is static and foldable. Both operands are static, | |
4642 | -- and neither raises constraint error, so we can definitely fold. | |
4643 | ||
4644 | else | |
4645 | Set_Is_Static_Expression (N); | |
4646 | Fold := True; | |
4647 | Stat := True; | |
4648 | return; | |
4649 | end if; | |
4650 | end Test_Expression_Is_Foldable; | |
4651 | ||
4652 | -------------- | |
4653 | -- To_Bits -- | |
4654 | -------------- | |
4655 | ||
4656 | procedure To_Bits (U : Uint; B : out Bits) is | |
4657 | begin | |
4658 | for J in 0 .. B'Last loop | |
4659 | B (J) := (U / (2 ** J)) mod 2 /= 0; | |
4660 | end loop; | |
4661 | end To_Bits; | |
4662 | ||
fbf5a39b AC |
4663 | -------------------- |
4664 | -- Why_Not_Static -- | |
4665 | -------------------- | |
4666 | ||
4667 | procedure Why_Not_Static (Expr : Node_Id) is | |
4668 | N : constant Node_Id := Original_Node (Expr); | |
4669 | Typ : Entity_Id; | |
4670 | E : Entity_Id; | |
4671 | ||
4672 | procedure Why_Not_Static_List (L : List_Id); | |
4673 | -- A version that can be called on a list of expressions. Finds | |
4674 | -- all non-static violations in any element of the list. | |
4675 | ||
4676 | ------------------------- | |
4677 | -- Why_Not_Static_List -- | |
4678 | ------------------------- | |
4679 | ||
4680 | procedure Why_Not_Static_List (L : List_Id) is | |
4681 | N : Node_Id; | |
4682 | ||
4683 | begin | |
4684 | if Is_Non_Empty_List (L) then | |
4685 | N := First (L); | |
4686 | while Present (N) loop | |
4687 | Why_Not_Static (N); | |
4688 | Next (N); | |
4689 | end loop; | |
4690 | end if; | |
4691 | end Why_Not_Static_List; | |
4692 | ||
4693 | -- Start of processing for Why_Not_Static | |
4694 | ||
4695 | begin | |
4696 | -- If in ACATS mode (debug flag 2), then suppress all these | |
4697 | -- messages, this avoids massive updates to the ACATS base line. | |
4698 | ||
4699 | if Debug_Flag_2 then | |
4700 | return; | |
4701 | end if; | |
4702 | ||
4703 | -- Ignore call on error or empty node | |
4704 | ||
4705 | if No (Expr) or else Nkind (Expr) = N_Error then | |
4706 | return; | |
4707 | end if; | |
4708 | ||
4709 | -- Preprocessing for sub expressions | |
4710 | ||
4711 | if Nkind (Expr) in N_Subexpr then | |
4712 | ||
4713 | -- Nothing to do if expression is static | |
4714 | ||
4715 | if Is_OK_Static_Expression (Expr) then | |
4716 | return; | |
4717 | end if; | |
4718 | ||
4719 | -- Test for constraint error raised | |
4720 | ||
4721 | if Raises_Constraint_Error (Expr) then | |
4722 | Error_Msg_N | |
4723 | ("expression raises exception, cannot be static " & | |
b11e8d6f | 4724 | "(RM 4.9(34))!", N); |
fbf5a39b AC |
4725 | return; |
4726 | end if; | |
4727 | ||
4728 | -- If no type, then something is pretty wrong, so ignore | |
4729 | ||
4730 | Typ := Etype (Expr); | |
4731 | ||
4732 | if No (Typ) then | |
4733 | return; | |
4734 | end if; | |
4735 | ||
4736 | -- Type must be scalar or string type | |
4737 | ||
4738 | if not Is_Scalar_Type (Typ) | |
4739 | and then not Is_String_Type (Typ) | |
4740 | then | |
4741 | Error_Msg_N | |
4742 | ("static expression must have scalar or string type " & | |
b11e8d6f | 4743 | "(RM 4.9(2))!", N); |
fbf5a39b AC |
4744 | return; |
4745 | end if; | |
4746 | end if; | |
4747 | ||
4748 | -- If we got through those checks, test particular node kind | |
4749 | ||
4750 | case Nkind (N) is | |
4751 | when N_Expanded_Name | N_Identifier | N_Operator_Symbol => | |
4752 | E := Entity (N); | |
4753 | ||
4754 | if Is_Named_Number (E) then | |
4755 | null; | |
4756 | ||
4757 | elsif Ekind (E) = E_Constant then | |
4758 | if not Is_Static_Expression (Constant_Value (E)) then | |
4759 | Error_Msg_NE | |
b11e8d6f | 4760 | ("& is not a static constant (RM 4.9(5))!", N, E); |
fbf5a39b AC |
4761 | end if; |
4762 | ||
4763 | else | |
4764 | Error_Msg_NE | |
4765 | ("& is not static constant or named number " & | |
b11e8d6f | 4766 | "(RM 4.9(5))!", N, E); |
fbf5a39b AC |
4767 | end if; |
4768 | ||
29797f34 | 4769 | when N_Binary_Op | N_And_Then | N_Or_Else | N_Membership_Test => |
fbf5a39b AC |
4770 | if Nkind (N) in N_Op_Shift then |
4771 | Error_Msg_N | |
b11e8d6f | 4772 | ("shift functions are never static (RM 4.9(6,18))!", N); |
fbf5a39b AC |
4773 | |
4774 | else | |
4775 | Why_Not_Static (Left_Opnd (N)); | |
4776 | Why_Not_Static (Right_Opnd (N)); | |
4777 | end if; | |
4778 | ||
4779 | when N_Unary_Op => | |
4780 | Why_Not_Static (Right_Opnd (N)); | |
4781 | ||
4782 | when N_Attribute_Reference => | |
4783 | Why_Not_Static_List (Expressions (N)); | |
4784 | ||
4785 | E := Etype (Prefix (N)); | |
4786 | ||
4787 | if E = Standard_Void_Type then | |
4788 | return; | |
4789 | end if; | |
4790 | ||
4791 | -- Special case non-scalar'Size since this is a common error | |
4792 | ||
4793 | if Attribute_Name (N) = Name_Size then | |
4794 | Error_Msg_N | |
4795 | ("size attribute is only static for scalar type " & | |
b11e8d6f | 4796 | "(RM 4.9(7,8))", N); |
fbf5a39b AC |
4797 | |
4798 | -- Flag array cases | |
4799 | ||
4800 | elsif Is_Array_Type (E) then | |
4801 | if Attribute_Name (N) /= Name_First | |
4802 | and then | |
4803 | Attribute_Name (N) /= Name_Last | |
4804 | and then | |
4805 | Attribute_Name (N) /= Name_Length | |
4806 | then | |
4807 | Error_Msg_N | |
4808 | ("static array attribute must be Length, First, or Last " & | |
b11e8d6f | 4809 | "(RM 4.9(8))!", N); |
fbf5a39b AC |
4810 | |
4811 | -- Since we know the expression is not-static (we already | |
4812 | -- tested for this, must mean array is not static). | |
4813 | ||
4814 | else | |
4815 | Error_Msg_N | |
b11e8d6f | 4816 | ("prefix is non-static array (RM 4.9(8))!", Prefix (N)); |
fbf5a39b AC |
4817 | end if; |
4818 | ||
4819 | return; | |
4820 | ||
4821 | -- Special case generic types, since again this is a common | |
4822 | -- source of confusion. | |
4823 | ||
4824 | elsif Is_Generic_Actual_Type (E) | |
4825 | or else | |
4826 | Is_Generic_Type (E) | |
4827 | then | |
4828 | Error_Msg_N | |
4829 | ("attribute of generic type is never static " & | |
b11e8d6f | 4830 | "(RM 4.9(7,8))!", N); |
fbf5a39b AC |
4831 | |
4832 | elsif Is_Static_Subtype (E) then | |
4833 | null; | |
4834 | ||
4835 | elsif Is_Scalar_Type (E) then | |
4836 | Error_Msg_N | |
4837 | ("prefix type for attribute is not static scalar subtype " & | |
b11e8d6f | 4838 | "(RM 4.9(7))!", N); |
fbf5a39b AC |
4839 | |
4840 | else | |
4841 | Error_Msg_N | |
4842 | ("static attribute must apply to array/scalar type " & | |
b11e8d6f | 4843 | "(RM 4.9(7,8))!", N); |
fbf5a39b AC |
4844 | end if; |
4845 | ||
4846 | when N_String_Literal => | |
4847 | Error_Msg_N | |
b11e8d6f | 4848 | ("subtype of string literal is non-static (RM 4.9(4))!", N); |
fbf5a39b AC |
4849 | |
4850 | when N_Explicit_Dereference => | |
4851 | Error_Msg_N | |
b11e8d6f | 4852 | ("explicit dereference is never static (RM 4.9)!", N); |
fbf5a39b AC |
4853 | |
4854 | when N_Function_Call => | |
4855 | Why_Not_Static_List (Parameter_Associations (N)); | |
b11e8d6f | 4856 | Error_Msg_N ("non-static function call (RM 4.9(6,18))!", N); |
fbf5a39b AC |
4857 | |
4858 | when N_Parameter_Association => | |
4859 | Why_Not_Static (Explicit_Actual_Parameter (N)); | |
4860 | ||
4861 | when N_Indexed_Component => | |
4862 | Error_Msg_N | |
b11e8d6f | 4863 | ("indexed component is never static (RM 4.9)!", N); |
fbf5a39b AC |
4864 | |
4865 | when N_Procedure_Call_Statement => | |
4866 | Error_Msg_N | |
b11e8d6f | 4867 | ("procedure call is never static (RM 4.9)!", N); |
fbf5a39b AC |
4868 | |
4869 | when N_Qualified_Expression => | |
4870 | Why_Not_Static (Expression (N)); | |
4871 | ||
4872 | when N_Aggregate | N_Extension_Aggregate => | |
4873 | Error_Msg_N | |
b11e8d6f | 4874 | ("an aggregate is never static (RM 4.9)!", N); |
fbf5a39b AC |
4875 | |
4876 | when N_Range => | |
4877 | Why_Not_Static (Low_Bound (N)); | |
4878 | Why_Not_Static (High_Bound (N)); | |
4879 | ||
4880 | when N_Range_Constraint => | |
4881 | Why_Not_Static (Range_Expression (N)); | |
4882 | ||
4883 | when N_Subtype_Indication => | |
4884 | Why_Not_Static (Constraint (N)); | |
4885 | ||
4886 | when N_Selected_Component => | |
4887 | Error_Msg_N | |
b11e8d6f | 4888 | ("selected component is never static (RM 4.9)!", N); |
fbf5a39b AC |
4889 | |
4890 | when N_Slice => | |
4891 | Error_Msg_N | |
b11e8d6f | 4892 | ("slice is never static (RM 4.9)!", N); |
fbf5a39b AC |
4893 | |
4894 | when N_Type_Conversion => | |
4895 | Why_Not_Static (Expression (N)); | |
4896 | ||
4897 | if not Is_Scalar_Type (Etype (Prefix (N))) | |
4898 | or else not Is_Static_Subtype (Etype (Prefix (N))) | |
4899 | then | |
4900 | Error_Msg_N | |
4901 | ("static conversion requires static scalar subtype result " & | |
b11e8d6f | 4902 | "(RM 4.9(9))!", N); |
fbf5a39b AC |
4903 | end if; |
4904 | ||
4905 | when N_Unchecked_Type_Conversion => | |
4906 | Error_Msg_N | |
b11e8d6f | 4907 | ("unchecked type conversion is never static (RM 4.9)!", N); |
fbf5a39b AC |
4908 | |
4909 | when others => | |
4910 | null; | |
4911 | ||
4912 | end case; | |
4913 | end Why_Not_Static; | |
4914 | ||
996ae0b0 | 4915 | end Sem_Eval; |