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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 | -- -- | |
634a926b | 9 | -- Copyright (C) 1992-2017, 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 | ||
ca0eb951 | 26 | with Aspects; use Aspects; |
996ae0b0 RK |
27 | with Atree; use Atree; |
28 | with Checks; use Checks; | |
29 | with Debug; use Debug; | |
30 | with Einfo; use Einfo; | |
31 | with Elists; use Elists; | |
32 | with Errout; use Errout; | |
33 | with Eval_Fat; use Eval_Fat; | |
8cbb664e | 34 | with Exp_Util; use Exp_Util; |
d7567964 | 35 | with Freeze; use Freeze; |
0356699b | 36 | with Lib; use Lib; |
13f34a3f | 37 | with Namet; use Namet; |
996ae0b0 RK |
38 | with Nmake; use Nmake; |
39 | with Nlists; use Nlists; | |
40 | with Opt; use Opt; | |
e03f7ccf | 41 | with Par_SCO; use Par_SCO; |
65f7ed64 | 42 | with Rtsfind; use Rtsfind; |
996ae0b0 | 43 | with Sem; use Sem; |
a4100e55 | 44 | with Sem_Aux; use Sem_Aux; |
996ae0b0 | 45 | with Sem_Cat; use Sem_Cat; |
b5bd964f | 46 | with Sem_Ch6; use Sem_Ch6; |
996ae0b0 RK |
47 | with Sem_Ch8; use Sem_Ch8; |
48 | with Sem_Res; use Sem_Res; | |
49 | with Sem_Util; use Sem_Util; | |
50 | with Sem_Type; use Sem_Type; | |
51 | with Sem_Warn; use Sem_Warn; | |
52 | with Sinfo; use Sinfo; | |
53 | with Snames; use Snames; | |
54 | with Stand; use Stand; | |
55 | with Stringt; use Stringt; | |
07fc65c4 | 56 | with Tbuild; use Tbuild; |
996ae0b0 RK |
57 | |
58 | package body Sem_Eval is | |
59 | ||
60 | ----------------------------------------- | |
61 | -- Handling of Compile Time Evaluation -- | |
62 | ----------------------------------------- | |
63 | ||
64 | -- The compile time evaluation of expressions is distributed over several | |
f3d57416 | 65 | -- Eval_xxx procedures. These procedures are called immediately after |
996ae0b0 RK |
66 | -- a subexpression is resolved and is therefore accomplished in a bottom |
67 | -- up fashion. The flags are synthesized using the following approach. | |
68 | ||
69 | -- Is_Static_Expression is determined by following the detailed rules | |
70 | -- in RM 4.9(4-14). This involves testing the Is_Static_Expression | |
71 | -- flag of the operands in many cases. | |
72 | ||
73 | -- Raises_Constraint_Error is set if any of the operands have the flag | |
74 | -- set or if an attempt to compute the value of the current expression | |
75 | -- results in detection of a runtime constraint error. | |
76 | ||
77 | -- As described in the spec, the requirement is that Is_Static_Expression | |
78 | -- be accurately set, and in addition for nodes for which this flag is set, | |
79 | -- Raises_Constraint_Error must also be set. Furthermore a node which has | |
80 | -- Is_Static_Expression set, and Raises_Constraint_Error clear, then the | |
81 | -- requirement is that the expression value must be precomputed, and the | |
82 | -- node is either a literal, or the name of a constant entity whose value | |
83 | -- is a static expression. | |
84 | ||
85 | -- The general approach is as follows. First compute Is_Static_Expression. | |
86 | -- If the node is not static, then the flag is left off in the node and | |
87 | -- we are all done. Otherwise for a static node, we test if any of the | |
88 | -- operands will raise constraint error, and if so, propagate the flag | |
89 | -- Raises_Constraint_Error to the result node and we are done (since the | |
90 | -- error was already posted at a lower level). | |
91 | ||
92 | -- For the case of a static node whose operands do not raise constraint | |
93 | -- error, we attempt to evaluate the node. If this evaluation succeeds, | |
94 | -- then the node is replaced by the result of this computation. If the | |
95 | -- evaluation raises constraint error, then we rewrite the node with | |
96 | -- Apply_Compile_Time_Constraint_Error to raise the exception and also | |
97 | -- to post appropriate error messages. | |
98 | ||
99 | ---------------- | |
100 | -- Local Data -- | |
101 | ---------------- | |
102 | ||
103 | type Bits is array (Nat range <>) of Boolean; | |
104 | -- Used to convert unsigned (modular) values for folding logical ops | |
105 | ||
80298c3b | 106 | -- The following declarations are used to maintain a cache of nodes that |
07fc65c4 GB |
107 | -- have compile time known values. The cache is maintained only for |
108 | -- discrete types (the most common case), and is populated by calls to | |
109 | -- Compile_Time_Known_Value and Expr_Value, but only used by Expr_Value | |
110 | -- since it is possible for the status to change (in particular it is | |
111 | -- possible for a node to get replaced by a constraint error node). | |
112 | ||
113 | CV_Bits : constant := 5; | |
114 | -- Number of low order bits of Node_Id value used to reference entries | |
115 | -- in the cache table. | |
116 | ||
117 | CV_Cache_Size : constant Nat := 2 ** CV_Bits; | |
118 | -- Size of cache for compile time values | |
119 | ||
120 | subtype CV_Range is Nat range 0 .. CV_Cache_Size; | |
121 | ||
122 | type CV_Entry is record | |
123 | N : Node_Id; | |
124 | V : Uint; | |
125 | end record; | |
126 | ||
edab6088 RD |
127 | type Match_Result is (Match, No_Match, Non_Static); |
128 | -- Result returned from functions that test for a matching result. If the | |
129 | -- operands are not OK_Static then Non_Static will be returned. Otherwise | |
130 | -- Match/No_Match is returned depending on whether the match succeeds. | |
131 | ||
07fc65c4 GB |
132 | type CV_Cache_Array is array (CV_Range) of CV_Entry; |
133 | ||
134 | CV_Cache : CV_Cache_Array := (others => (Node_High_Bound, Uint_0)); | |
135 | -- This is the actual cache, with entries consisting of node/value pairs, | |
136 | -- and the impossible value Node_High_Bound used for unset entries. | |
137 | ||
305caf42 AC |
138 | type Range_Membership is (In_Range, Out_Of_Range, Unknown); |
139 | -- Range membership may either be statically known to be in range or out | |
140 | -- of range, or not statically known. Used for Test_In_Range below. | |
141 | ||
996ae0b0 RK |
142 | ----------------------- |
143 | -- Local Subprograms -- | |
144 | ----------------------- | |
145 | ||
edab6088 RD |
146 | function Choice_Matches |
147 | (Expr : Node_Id; | |
148 | Choice : Node_Id) return Match_Result; | |
149 | -- Determines whether given value Expr matches the given Choice. The Expr | |
150 | -- can be of discrete, real, or string type and must be a compile time | |
151 | -- known value (it is an error to make the call if these conditions are | |
152 | -- not met). The choice can be a range, subtype name, subtype indication, | |
153 | -- or expression. The returned result is Non_Static if Choice is not | |
154 | -- OK_Static, otherwise either Match or No_Match is returned depending | |
155 | -- on whether Choice matches Expr. This is used for case expression | |
156 | -- alternatives, and also for membership tests. In each case, more | |
157 | -- possibilities are tested than the syntax allows (e.g. membership allows | |
158 | -- subtype indications and non-discrete types, and case allows an OTHERS | |
159 | -- choice), but it does not matter, since we have already done a full | |
160 | -- semantic and syntax check of the construct, so the extra possibilities | |
161 | -- just will not arise for correct expressions. | |
162 | -- | |
163 | -- Note: if Choice_Matches finds that a choice raises Constraint_Error, e.g | |
164 | -- a reference to a type, one of whose bounds raises Constraint_Error, then | |
165 | -- it also sets the Raises_Constraint_Error flag on the Choice itself. | |
166 | ||
167 | function Choices_Match | |
168 | (Expr : Node_Id; | |
169 | Choices : List_Id) return Match_Result; | |
170 | -- This function applies Choice_Matches to each element of Choices. If the | |
171 | -- result is No_Match, then it continues and checks the next element. If | |
172 | -- the result is Match or Non_Static, this result is immediately given | |
173 | -- as the result without checking the rest of the list. Expr can be of | |
174 | -- discrete, real, or string type and must be a compile time known value | |
175 | -- (it is an error to make the call if these conditions are not met). | |
176 | ||
87feba05 AC |
177 | function Find_Universal_Operator_Type (N : Node_Id) return Entity_Id; |
178 | -- Check whether an arithmetic operation with universal operands which is a | |
179 | -- rewritten function call with an explicit scope indication is ambiguous: | |
180 | -- P."+" (1, 2) will be ambiguous if there is more than one visible numeric | |
181 | -- type declared in P and the context does not impose a type on the result | |
182 | -- (e.g. in the expression of a type conversion). If ambiguous, emit an | |
183 | -- error and return Empty, else return the result type of the operator. | |
184 | ||
996ae0b0 | 185 | function From_Bits (B : Bits; T : Entity_Id) return Uint; |
80298c3b AC |
186 | -- Converts a bit string of length B'Length to a Uint value to be used for |
187 | -- a target of type T, which is a modular type. This procedure includes the | |
a95f708e | 188 | -- necessary reduction by the modulus in the case of a nonbinary modulus |
80298c3b AC |
189 | -- (for a binary modulus, the bit string is the right length any way so all |
190 | -- is well). | |
996ae0b0 | 191 | |
87feba05 AC |
192 | function Get_String_Val (N : Node_Id) return Node_Id; |
193 | -- Given a tree node for a folded string or character value, returns the | |
194 | -- corresponding string literal or character literal (one of the two must | |
195 | -- be available, or the operand would not have been marked as foldable in | |
196 | -- the earlier analysis of the operation). | |
edab6088 RD |
197 | |
198 | function Is_OK_Static_Choice (Choice : Node_Id) return Boolean; | |
199 | -- Given a choice (from a case expression or membership test), returns | |
200 | -- True if the choice is static and does not raise a Constraint_Error. | |
201 | ||
202 | function Is_OK_Static_Choice_List (Choices : List_Id) return Boolean; | |
203 | -- Given a choice list (from a case expression or membership test), return | |
204 | -- True if all choices are static in the sense of Is_OK_Static_Choice. | |
205 | ||
87feba05 AC |
206 | function Is_Static_Choice (Choice : Node_Id) return Boolean; |
207 | -- Given a choice (from a case expression or membership test), returns | |
208 | -- True if the choice is static. No test is made for raising of constraint | |
209 | -- error, so this function is used only for legality tests. | |
210 | ||
211 | function Is_Static_Choice_List (Choices : List_Id) return Boolean; | |
212 | -- Given a choice list (from a case expression or membership test), return | |
213 | -- True if all choices are static in the sense of Is_Static_Choice. | |
214 | ||
edab6088 RD |
215 | function Is_Static_Range (N : Node_Id) return Boolean; |
216 | -- Determine if range is static, as defined in RM 4.9(26). The only allowed | |
217 | -- argument is an N_Range node (but note that the semantic analysis of | |
218 | -- equivalent range attribute references already turned them into the | |
219 | -- equivalent range). This differs from Is_OK_Static_Range (which is what | |
220 | -- must be used by clients) in that it does not care whether the bounds | |
221 | -- raise Constraint_Error or not. Used for checking whether expressions are | |
222 | -- static in the 4.9 sense (without worrying about exceptions). | |
223 | ||
07fc65c4 GB |
224 | function OK_Bits (N : Node_Id; Bits : Uint) return Boolean; |
225 | -- Bits represents the number of bits in an integer value to be computed | |
226 | -- (but the value has not been computed yet). If this value in Bits is | |
80298c3b AC |
227 | -- reasonable, a result of True is returned, with the implication that the |
228 | -- caller should go ahead and complete the calculation. If the value in | |
229 | -- Bits is unreasonably large, then an error is posted on node N, and | |
07fc65c4 GB |
230 | -- False is returned (and the caller skips the proposed calculation). |
231 | ||
996ae0b0 | 232 | procedure Out_Of_Range (N : Node_Id); |
80298c3b AC |
233 | -- This procedure is called if it is determined that node N, which appears |
234 | -- in a non-static context, is a compile time known value which is outside | |
235 | -- its range, i.e. the range of Etype. This is used in contexts where | |
236 | -- this is an illegality if N is static, and should generate a warning | |
237 | -- otherwise. | |
996ae0b0 | 238 | |
fc3a3f3b RD |
239 | function Real_Or_String_Static_Predicate_Matches |
240 | (Val : Node_Id; | |
241 | Typ : Entity_Id) return Boolean; | |
242 | -- This is the function used to evaluate real or string static predicates. | |
243 | -- Val is an unanalyzed N_Real_Literal or N_String_Literal node, which | |
244 | -- represents the value to be tested against the predicate. Typ is the | |
245 | -- type with the predicate, from which the predicate expression can be | |
246 | -- extracted. The result returned is True if the given value satisfies | |
247 | -- the predicate. | |
248 | ||
996ae0b0 | 249 | procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id); |
80298c3b AC |
250 | -- N and Exp are nodes representing an expression, Exp is known to raise |
251 | -- CE. N is rewritten in term of Exp in the optimal way. | |
996ae0b0 RK |
252 | |
253 | function String_Type_Len (Stype : Entity_Id) return Uint; | |
80298c3b AC |
254 | -- Given a string type, determines the length of the index type, or, if |
255 | -- this index type is non-static, the length of the base type of this index | |
256 | -- type. Note that if the string type is itself static, then the index type | |
257 | -- is static, so the second case applies only if the string type passed is | |
258 | -- non-static. | |
996ae0b0 RK |
259 | |
260 | function Test (Cond : Boolean) return Uint; | |
261 | pragma Inline (Test); | |
262 | -- This function simply returns the appropriate Boolean'Pos value | |
263 | -- corresponding to the value of Cond as a universal integer. It is | |
264 | -- used for producing the result of the static evaluation of the | |
265 | -- logical operators | |
266 | ||
267 | procedure Test_Expression_Is_Foldable | |
268 | (N : Node_Id; | |
269 | Op1 : Node_Id; | |
270 | Stat : out Boolean; | |
271 | Fold : out Boolean); | |
272 | -- Tests to see if expression N whose single operand is Op1 is foldable, | |
273 | -- i.e. the operand value is known at compile time. If the operation is | |
80298c3b AC |
274 | -- foldable, then Fold is True on return, and Stat indicates whether the |
275 | -- result is static (i.e. the operand was static). Note that it is quite | |
276 | -- possible for Fold to be True, and Stat to be False, since there are | |
277 | -- cases in which we know the value of an operand even though it is not | |
278 | -- technically static (e.g. the static lower bound of a range whose upper | |
279 | -- bound is non-static). | |
996ae0b0 | 280 | -- |
80298c3b AC |
281 | -- If Stat is set False on return, then Test_Expression_Is_Foldable makes |
282 | -- a call to Check_Non_Static_Context on the operand. If Fold is False on | |
283 | -- return, then all processing is complete, and the caller should return, | |
284 | -- since there is nothing else to do. | |
93c3fca7 AC |
285 | -- |
286 | -- If Stat is set True on return, then Is_Static_Expression is also set | |
287 | -- true in node N. There are some cases where this is over-enthusiastic, | |
80298c3b AC |
288 | -- e.g. in the two operand case below, for string comparison, the result is |
289 | -- not static even though the two operands are static. In such cases, the | |
290 | -- caller must reset the Is_Static_Expression flag in N. | |
5df1266a AC |
291 | -- |
292 | -- If Fold and Stat are both set to False then this routine performs also | |
293 | -- the following extra actions: | |
294 | -- | |
80298c3b AC |
295 | -- If either operand is Any_Type then propagate it to result to prevent |
296 | -- cascaded errors. | |
5df1266a | 297 | -- |
70805b88 AC |
298 | -- If some operand raises constraint error, then replace the node N |
299 | -- with the raise constraint error node. This replacement inherits the | |
300 | -- Is_Static_Expression flag from the operands. | |
996ae0b0 RK |
301 | |
302 | procedure Test_Expression_Is_Foldable | |
6c3c671e AC |
303 | (N : Node_Id; |
304 | Op1 : Node_Id; | |
305 | Op2 : Node_Id; | |
306 | Stat : out Boolean; | |
307 | Fold : out Boolean; | |
308 | CRT_Safe : Boolean := False); | |
996ae0b0 | 309 | -- Same processing, except applies to an expression N with two operands |
6c3c671e AC |
310 | -- Op1 and Op2. The result is static only if both operands are static. If |
311 | -- CRT_Safe is set True, then CRT_Safe_Compile_Time_Known_Value is used | |
312 | -- for the tests that the two operands are known at compile time. See | |
313 | -- spec of this routine for further details. | |
996ae0b0 | 314 | |
305caf42 AC |
315 | function Test_In_Range |
316 | (N : Node_Id; | |
317 | Typ : Entity_Id; | |
318 | Assume_Valid : Boolean; | |
319 | Fixed_Int : Boolean; | |
320 | Int_Real : Boolean) return Range_Membership; | |
9479ded4 AC |
321 | -- Common processing for Is_In_Range and Is_Out_Of_Range: Returns In_Range |
322 | -- or Out_Of_Range if it can be guaranteed at compile time that expression | |
323 | -- N is known to be in or out of range of the subtype Typ. If not compile | |
324 | -- time known, Unknown is returned. See documentation of Is_In_Range for | |
325 | -- complete description of parameters. | |
305caf42 | 326 | |
996ae0b0 RK |
327 | procedure To_Bits (U : Uint; B : out Bits); |
328 | -- Converts a Uint value to a bit string of length B'Length | |
329 | ||
edab6088 RD |
330 | ----------------------------------------------- |
331 | -- Check_Expression_Against_Static_Predicate -- | |
332 | ----------------------------------------------- | |
333 | ||
334 | procedure Check_Expression_Against_Static_Predicate | |
335 | (Expr : Node_Id; | |
336 | Typ : Entity_Id) | |
337 | is | |
338 | begin | |
339 | -- Nothing to do if expression is not known at compile time, or the | |
340 | -- type has no static predicate set (will be the case for all non-scalar | |
341 | -- types, so no need to make a special test for that). | |
342 | ||
343 | if not (Has_Static_Predicate (Typ) | |
60f908dd | 344 | and then Compile_Time_Known_Value (Expr)) |
edab6088 RD |
345 | then |
346 | return; | |
347 | end if; | |
348 | ||
349 | -- Here we have a static predicate (note that it could have arisen from | |
350 | -- an explicitly specified Dynamic_Predicate whose expression met the | |
d9c59db4 AC |
351 | -- rules for being predicate-static). If the expression is known at |
352 | -- compile time and obeys the predicate, then it is static and must be | |
353 | -- labeled as such, which matters e.g. for case statements. The original | |
354 | -- expression may be a type conversion of a variable with a known value, | |
355 | -- which might otherwise not be marked static. | |
edab6088 | 356 | |
fc3a3f3b | 357 | -- Case of real static predicate |
edab6088 | 358 | |
fc3a3f3b RD |
359 | if Is_Real_Type (Typ) then |
360 | if Real_Or_String_Static_Predicate_Matches | |
361 | (Val => Make_Real_Literal (Sloc (Expr), Expr_Value_R (Expr)), | |
362 | Typ => Typ) | |
363 | then | |
d9c59db4 | 364 | Set_Is_Static_Expression (Expr); |
fc3a3f3b RD |
365 | return; |
366 | end if; | |
edab6088 | 367 | |
fc3a3f3b | 368 | -- Case of string static predicate |
edab6088 | 369 | |
fc3a3f3b RD |
370 | elsif Is_String_Type (Typ) then |
371 | if Real_Or_String_Static_Predicate_Matches | |
f9e333ab | 372 | (Val => Expr_Value_S (Expr), Typ => Typ) |
fc3a3f3b | 373 | then |
d9c59db4 | 374 | Set_Is_Static_Expression (Expr); |
fc3a3f3b RD |
375 | return; |
376 | end if; | |
edab6088 | 377 | |
fc3a3f3b | 378 | -- Case of discrete static predicate |
edab6088 | 379 | |
fc3a3f3b RD |
380 | else |
381 | pragma Assert (Is_Discrete_Type (Typ)); | |
382 | ||
383 | -- If static predicate matches, nothing to do | |
384 | ||
385 | if Choices_Match (Expr, Static_Discrete_Predicate (Typ)) = Match then | |
d9c59db4 | 386 | Set_Is_Static_Expression (Expr); |
fc3a3f3b RD |
387 | return; |
388 | end if; | |
edab6088 RD |
389 | end if; |
390 | ||
391 | -- Here we know that the predicate will fail | |
392 | ||
393 | -- Special case of static expression failing a predicate (other than one | |
394 | -- that was explicitly specified with a Dynamic_Predicate aspect). This | |
395 | -- is the case where the expression is no longer considered static. | |
396 | ||
397 | if Is_Static_Expression (Expr) | |
398 | and then not Has_Dynamic_Predicate_Aspect (Typ) | |
399 | then | |
400 | Error_Msg_NE | |
401 | ("??static expression fails static predicate check on &", | |
402 | Expr, Typ); | |
403 | Error_Msg_N | |
404 | ("\??expression is no longer considered static", Expr); | |
405 | Set_Is_Static_Expression (Expr, False); | |
406 | ||
407 | -- In all other cases, this is just a warning that a test will fail. | |
408 | -- It does not matter if the expression is static or not, or if the | |
409 | -- predicate comes from a dynamic predicate aspect or not. | |
410 | ||
411 | else | |
412 | Error_Msg_NE | |
413 | ("??expression fails predicate check on &", Expr, Typ); | |
414 | end if; | |
415 | end Check_Expression_Against_Static_Predicate; | |
60f908dd | 416 | |
996ae0b0 RK |
417 | ------------------------------ |
418 | -- Check_Non_Static_Context -- | |
419 | ------------------------------ | |
420 | ||
421 | procedure Check_Non_Static_Context (N : Node_Id) is | |
fbf5a39b AC |
422 | T : constant Entity_Id := Etype (N); |
423 | Checks_On : constant Boolean := | |
996ae0b0 RK |
424 | not Index_Checks_Suppressed (T) |
425 | and not Range_Checks_Suppressed (T); | |
426 | ||
427 | begin | |
86f0e17a AC |
428 | -- Ignore cases of non-scalar types, error types, or universal real |
429 | -- types that have no usable bounds. | |
996ae0b0 | 430 | |
86f0e17a AC |
431 | if T = Any_Type |
432 | or else not Is_Scalar_Type (T) | |
433 | or else T = Universal_Fixed | |
434 | or else T = Universal_Real | |
435 | then | |
996ae0b0 | 436 | return; |
fbf5a39b | 437 | end if; |
996ae0b0 | 438 | |
86f0e17a | 439 | -- At this stage we have a scalar type. If we have an expression that |
80298c3b AC |
440 | -- raises CE, then we already issued a warning or error msg so there is |
441 | -- nothing more to be done in this routine. | |
fbf5a39b AC |
442 | |
443 | if Raises_Constraint_Error (N) then | |
444 | return; | |
445 | end if; | |
446 | ||
86f0e17a AC |
447 | -- Now we have a scalar type which is not marked as raising a constraint |
448 | -- error exception. The main purpose of this routine is to deal with | |
449 | -- static expressions appearing in a non-static context. That means | |
450 | -- that if we do not have a static expression then there is not much | |
451 | -- to do. The one case that we deal with here is that if we have a | |
452 | -- floating-point value that is out of range, then we post a warning | |
453 | -- that an infinity will result. | |
fbf5a39b AC |
454 | |
455 | if not Is_Static_Expression (N) then | |
d030f3a4 AC |
456 | if Is_Floating_Point_Type (T) then |
457 | if Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) then | |
458 | Error_Msg_N | |
459 | ("??float value out of range, infinity will be generated", N); | |
460 | ||
461 | -- The literal may be the result of constant-folding of a non- | |
462 | -- static subexpression of a larger expression (e.g. a conversion | |
463 | -- of a non-static variable whose value happens to be known). At | |
464 | -- this point we must reduce the value of the subexpression to a | |
465 | -- machine number (RM 4.9 (38/2)). | |
466 | ||
467 | elsif Nkind (N) = N_Real_Literal | |
468 | and then Nkind (Parent (N)) in N_Subexpr | |
469 | then | |
470 | Rewrite (N, New_Copy (N)); | |
471 | Set_Realval | |
472 | (N, Machine (Base_Type (T), Realval (N), Round_Even, N)); | |
473 | end if; | |
fbf5a39b | 474 | end if; |
996ae0b0 | 475 | |
996ae0b0 RK |
476 | return; |
477 | end if; | |
478 | ||
86f0e17a AC |
479 | -- Here we have the case of outer level static expression of scalar |
480 | -- type, where the processing of this procedure is needed. | |
996ae0b0 RK |
481 | |
482 | -- For real types, this is where we convert the value to a machine | |
86f0e17a AC |
483 | -- number (see RM 4.9(38)). Also see ACVC test C490001. We should only |
484 | -- need to do this if the parent is a constant declaration, since in | |
485 | -- other cases, gigi should do the necessary conversion correctly, but | |
486 | -- experimentation shows that this is not the case on all machines, in | |
487 | -- particular if we do not convert all literals to machine values in | |
488 | -- non-static contexts, then ACVC test C490001 fails on Sparc/Solaris | |
489 | -- and SGI/Irix. | |
996ae0b0 | 490 | |
9d4f9832 AC |
491 | -- This conversion is always done by GNATprove on real literals in |
492 | -- non-static expressions, by calling Check_Non_Static_Context from | |
493 | -- gnat2why, as GNATprove cannot do the conversion later contrary | |
494 | -- to gigi. The frontend computes the information about which | |
495 | -- expressions are static, which is used by gnat2why to call | |
496 | -- Check_Non_Static_Context on exactly those real literals that are | |
497 | -- not sub-expressions of static expressions. | |
498 | ||
996ae0b0 RK |
499 | if Nkind (N) = N_Real_Literal |
500 | and then not Is_Machine_Number (N) | |
501 | and then not Is_Generic_Type (Etype (N)) | |
502 | and then Etype (N) /= Universal_Real | |
996ae0b0 RK |
503 | then |
504 | -- Check that value is in bounds before converting to machine | |
505 | -- number, so as not to lose case where value overflows in the | |
506 | -- least significant bit or less. See B490001. | |
507 | ||
c800f862 | 508 | if Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) then |
996ae0b0 RK |
509 | Out_Of_Range (N); |
510 | return; | |
511 | end if; | |
512 | ||
513 | -- Note: we have to copy the node, to avoid problems with conformance | |
514 | -- of very similar numbers (see ACVC tests B4A010C and B63103A). | |
515 | ||
516 | Rewrite (N, New_Copy (N)); | |
517 | ||
518 | if not Is_Floating_Point_Type (T) then | |
519 | Set_Realval | |
520 | (N, Corresponding_Integer_Value (N) * Small_Value (T)); | |
521 | ||
522 | elsif not UR_Is_Zero (Realval (N)) then | |
996ae0b0 | 523 | |
86f0e17a AC |
524 | -- Note: even though RM 4.9(38) specifies biased rounding, this |
525 | -- has been modified by AI-100 in order to prevent confusing | |
526 | -- differences in rounding between static and non-static | |
527 | -- expressions. AI-100 specifies that the effect of such rounding | |
528 | -- is implementation dependent, and in GNAT we round to nearest | |
ad075b50 AC |
529 | -- even to match the run-time behavior. Note that this applies |
530 | -- to floating point literals, not fixed points ones, even though | |
531 | -- their compiler representation is also as a universal real. | |
996ae0b0 | 532 | |
fbf5a39b AC |
533 | Set_Realval |
534 | (N, Machine (Base_Type (T), Realval (N), Round_Even, N)); | |
ad075b50 | 535 | Set_Is_Machine_Number (N); |
996ae0b0 RK |
536 | end if; |
537 | ||
996ae0b0 RK |
538 | end if; |
539 | ||
540 | -- Check for out of range universal integer. This is a non-static | |
541 | -- context, so the integer value must be in range of the runtime | |
542 | -- representation of universal integers. | |
543 | ||
544 | -- We do this only within an expression, because that is the only | |
545 | -- case in which non-static universal integer values can occur, and | |
546 | -- furthermore, Check_Non_Static_Context is currently (incorrectly???) | |
547 | -- called in contexts like the expression of a number declaration where | |
548 | -- we certainly want to allow out of range values. | |
549 | ||
550 | if Etype (N) = Universal_Integer | |
551 | and then Nkind (N) = N_Integer_Literal | |
552 | and then Nkind (Parent (N)) in N_Subexpr | |
553 | and then | |
554 | (Intval (N) < Expr_Value (Type_Low_Bound (Universal_Integer)) | |
80298c3b | 555 | or else |
996ae0b0 RK |
556 | Intval (N) > Expr_Value (Type_High_Bound (Universal_Integer))) |
557 | then | |
558 | Apply_Compile_Time_Constraint_Error | |
4a28b181 | 559 | (N, "non-static universal integer value out of range<<", |
07fc65c4 | 560 | CE_Range_Check_Failed); |
996ae0b0 RK |
561 | |
562 | -- Check out of range of base type | |
563 | ||
c800f862 | 564 | elsif Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) then |
996ae0b0 RK |
565 | Out_Of_Range (N); |
566 | ||
c800f862 RD |
567 | -- Give warning if outside subtype (where one or both of the bounds of |
568 | -- the subtype is static). This warning is omitted if the expression | |
569 | -- appears in a range that could be null (warnings are handled elsewhere | |
570 | -- for this case). | |
996ae0b0 | 571 | |
80298c3b | 572 | elsif T /= Base_Type (T) and then Nkind (Parent (N)) /= N_Range then |
c800f862 | 573 | if Is_In_Range (N, T, Assume_Valid => True) then |
996ae0b0 RK |
574 | null; |
575 | ||
c800f862 | 576 | elsif Is_Out_Of_Range (N, T, Assume_Valid => True) then |
996ae0b0 | 577 | Apply_Compile_Time_Constraint_Error |
4a28b181 | 578 | (N, "value not in range of}<<", CE_Range_Check_Failed); |
996ae0b0 RK |
579 | |
580 | elsif Checks_On then | |
581 | Enable_Range_Check (N); | |
582 | ||
583 | else | |
584 | Set_Do_Range_Check (N, False); | |
585 | end if; | |
586 | end if; | |
587 | end Check_Non_Static_Context; | |
588 | ||
589 | --------------------------------- | |
590 | -- Check_String_Literal_Length -- | |
591 | --------------------------------- | |
592 | ||
593 | procedure Check_String_Literal_Length (N : Node_Id; Ttype : Entity_Id) is | |
594 | begin | |
324ac540 | 595 | if not Raises_Constraint_Error (N) and then Is_Constrained (Ttype) then |
80298c3b | 596 | if UI_From_Int (String_Length (Strval (N))) /= String_Type_Len (Ttype) |
996ae0b0 RK |
597 | then |
598 | Apply_Compile_Time_Constraint_Error | |
324ac540 | 599 | (N, "string length wrong for}??", |
07fc65c4 | 600 | CE_Length_Check_Failed, |
996ae0b0 RK |
601 | Ent => Ttype, |
602 | Typ => Ttype); | |
603 | end if; | |
604 | end if; | |
605 | end Check_String_Literal_Length; | |
606 | ||
edab6088 RD |
607 | -------------------- |
608 | -- Choice_Matches -- | |
609 | -------------------- | |
610 | ||
611 | function Choice_Matches | |
612 | (Expr : Node_Id; | |
613 | Choice : Node_Id) return Match_Result | |
614 | is | |
615 | Etyp : constant Entity_Id := Etype (Expr); | |
616 | Val : Uint; | |
617 | ValR : Ureal; | |
618 | ValS : Node_Id; | |
619 | ||
620 | begin | |
621 | pragma Assert (Compile_Time_Known_Value (Expr)); | |
622 | pragma Assert (Is_Scalar_Type (Etyp) or else Is_String_Type (Etyp)); | |
623 | ||
624 | if not Is_OK_Static_Choice (Choice) then | |
625 | Set_Raises_Constraint_Error (Choice); | |
626 | return Non_Static; | |
627 | ||
87feba05 AC |
628 | -- When the choice denotes a subtype with a static predictate, check the |
629 | -- expression against the predicate values. | |
630 | ||
631 | elsif (Nkind (Choice) = N_Subtype_Indication | |
632 | or else (Is_Entity_Name (Choice) | |
633 | and then Is_Type (Entity (Choice)))) | |
634 | and then Has_Predicates (Etype (Choice)) | |
635 | and then Has_Static_Predicate (Etype (Choice)) | |
636 | then | |
637 | return | |
638 | Choices_Match (Expr, Static_Discrete_Predicate (Etype (Choice))); | |
639 | ||
edab6088 RD |
640 | -- Discrete type case |
641 | ||
87feba05 | 642 | elsif Is_Discrete_Type (Etyp) then |
edab6088 RD |
643 | Val := Expr_Value (Expr); |
644 | ||
645 | if Nkind (Choice) = N_Range then | |
646 | if Val >= Expr_Value (Low_Bound (Choice)) | |
647 | and then | |
648 | Val <= Expr_Value (High_Bound (Choice)) | |
649 | then | |
650 | return Match; | |
651 | else | |
652 | return No_Match; | |
653 | end if; | |
654 | ||
655 | elsif Nkind (Choice) = N_Subtype_Indication | |
87feba05 | 656 | or else (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice))) |
edab6088 RD |
657 | then |
658 | if Val >= Expr_Value (Type_Low_Bound (Etype (Choice))) | |
659 | and then | |
660 | Val <= Expr_Value (Type_High_Bound (Etype (Choice))) | |
661 | then | |
662 | return Match; | |
663 | else | |
664 | return No_Match; | |
665 | end if; | |
666 | ||
667 | elsif Nkind (Choice) = N_Others_Choice then | |
668 | return Match; | |
669 | ||
670 | else | |
671 | if Val = Expr_Value (Choice) then | |
672 | return Match; | |
673 | else | |
674 | return No_Match; | |
675 | end if; | |
676 | end if; | |
677 | ||
87feba05 | 678 | -- Real type case |
edab6088 | 679 | |
87feba05 | 680 | elsif Is_Real_Type (Etyp) then |
edab6088 RD |
681 | ValR := Expr_Value_R (Expr); |
682 | ||
683 | if Nkind (Choice) = N_Range then | |
684 | if ValR >= Expr_Value_R (Low_Bound (Choice)) | |
685 | and then | |
686 | ValR <= Expr_Value_R (High_Bound (Choice)) | |
687 | then | |
688 | return Match; | |
689 | else | |
690 | return No_Match; | |
691 | end if; | |
692 | ||
693 | elsif Nkind (Choice) = N_Subtype_Indication | |
87feba05 | 694 | or else (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice))) |
edab6088 RD |
695 | then |
696 | if ValR >= Expr_Value_R (Type_Low_Bound (Etype (Choice))) | |
697 | and then | |
698 | ValR <= Expr_Value_R (Type_High_Bound (Etype (Choice))) | |
699 | then | |
700 | return Match; | |
701 | else | |
702 | return No_Match; | |
703 | end if; | |
704 | ||
705 | else | |
706 | if ValR = Expr_Value_R (Choice) then | |
707 | return Match; | |
708 | else | |
709 | return No_Match; | |
710 | end if; | |
711 | end if; | |
712 | ||
87feba05 | 713 | -- String type cases |
edab6088 RD |
714 | |
715 | else | |
87feba05 | 716 | pragma Assert (Is_String_Type (Etyp)); |
edab6088 RD |
717 | ValS := Expr_Value_S (Expr); |
718 | ||
719 | if Nkind (Choice) = N_Subtype_Indication | |
87feba05 | 720 | or else (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice))) |
edab6088 RD |
721 | then |
722 | if not Is_Constrained (Etype (Choice)) then | |
723 | return Match; | |
724 | ||
725 | else | |
726 | declare | |
727 | Typlen : constant Uint := | |
728 | String_Type_Len (Etype (Choice)); | |
729 | Strlen : constant Uint := | |
730 | UI_From_Int (String_Length (Strval (ValS))); | |
731 | begin | |
732 | if Typlen = Strlen then | |
733 | return Match; | |
734 | else | |
735 | return No_Match; | |
736 | end if; | |
737 | end; | |
738 | end if; | |
739 | ||
740 | else | |
741 | if String_Equal (Strval (ValS), Strval (Expr_Value_S (Choice))) | |
742 | then | |
743 | return Match; | |
744 | else | |
745 | return No_Match; | |
746 | end if; | |
747 | end if; | |
748 | end if; | |
749 | end Choice_Matches; | |
750 | ||
751 | ------------------- | |
752 | -- Choices_Match -- | |
753 | ------------------- | |
754 | ||
755 | function Choices_Match | |
756 | (Expr : Node_Id; | |
757 | Choices : List_Id) return Match_Result | |
758 | is | |
759 | Choice : Node_Id; | |
760 | Result : Match_Result; | |
761 | ||
762 | begin | |
763 | Choice := First (Choices); | |
764 | while Present (Choice) loop | |
765 | Result := Choice_Matches (Expr, Choice); | |
766 | ||
767 | if Result /= No_Match then | |
768 | return Result; | |
769 | end if; | |
770 | ||
771 | Next (Choice); | |
772 | end loop; | |
773 | ||
774 | return No_Match; | |
775 | end Choices_Match; | |
776 | ||
996ae0b0 RK |
777 | -------------------------- |
778 | -- Compile_Time_Compare -- | |
779 | -------------------------- | |
780 | ||
fbf5a39b | 781 | function Compile_Time_Compare |
1c7717c3 | 782 | (L, R : Node_Id; |
af02a866 RD |
783 | Assume_Valid : Boolean) return Compare_Result |
784 | is | |
785 | Discard : aliased Uint; | |
786 | begin | |
787 | return Compile_Time_Compare (L, R, Discard'Access, Assume_Valid); | |
788 | end Compile_Time_Compare; | |
789 | ||
790 | function Compile_Time_Compare | |
791 | (L, R : Node_Id; | |
792 | Diff : access Uint; | |
1c7717c3 AC |
793 | Assume_Valid : Boolean; |
794 | Rec : Boolean := False) return Compare_Result | |
fbf5a39b | 795 | is |
08f52d9f AC |
796 | Ltyp : Entity_Id := Etype (L); |
797 | Rtyp : Entity_Id := Etype (R); | |
996ae0b0 | 798 | |
af02a866 RD |
799 | Discard : aliased Uint; |
800 | ||
996ae0b0 RK |
801 | procedure Compare_Decompose |
802 | (N : Node_Id; | |
803 | R : out Node_Id; | |
804 | V : out Uint); | |
b49365b2 RD |
805 | -- This procedure decomposes the node N into an expression node and a |
806 | -- signed offset, so that the value of N is equal to the value of R plus | |
807 | -- the value V (which may be negative). If no such decomposition is | |
808 | -- possible, then on return R is a copy of N, and V is set to zero. | |
996ae0b0 RK |
809 | |
810 | function Compare_Fixup (N : Node_Id) return Node_Id; | |
b49365b2 RD |
811 | -- This function deals with replacing 'Last and 'First references with |
812 | -- their corresponding type bounds, which we then can compare. The | |
813 | -- argument is the original node, the result is the identity, unless we | |
814 | -- have a 'Last/'First reference in which case the value returned is the | |
815 | -- appropriate type bound. | |
996ae0b0 | 816 | |
57036dcc ES |
817 | function Is_Known_Valid_Operand (Opnd : Node_Id) return Boolean; |
818 | -- Even if the context does not assume that values are valid, some | |
819 | -- simple cases can be recognized. | |
820 | ||
996ae0b0 | 821 | function Is_Same_Value (L, R : Node_Id) return Boolean; |
86f0e17a AC |
822 | -- Returns True iff L and R represent expressions that definitely have |
823 | -- identical (but not necessarily compile time known) values Indeed the | |
824 | -- caller is expected to have already dealt with the cases of compile | |
825 | -- time known values, so these are not tested here. | |
996ae0b0 RK |
826 | |
827 | ----------------------- | |
828 | -- Compare_Decompose -- | |
829 | ----------------------- | |
830 | ||
831 | procedure Compare_Decompose | |
832 | (N : Node_Id; | |
833 | R : out Node_Id; | |
834 | V : out Uint) | |
835 | is | |
836 | begin | |
837 | if Nkind (N) = N_Op_Add | |
838 | and then Nkind (Right_Opnd (N)) = N_Integer_Literal | |
839 | then | |
840 | R := Left_Opnd (N); | |
841 | V := Intval (Right_Opnd (N)); | |
842 | return; | |
843 | ||
844 | elsif Nkind (N) = N_Op_Subtract | |
845 | and then Nkind (Right_Opnd (N)) = N_Integer_Literal | |
846 | then | |
847 | R := Left_Opnd (N); | |
848 | V := UI_Negate (Intval (Right_Opnd (N))); | |
849 | return; | |
850 | ||
21d7ef70 | 851 | elsif Nkind (N) = N_Attribute_Reference then |
996ae0b0 RK |
852 | if Attribute_Name (N) = Name_Succ then |
853 | R := First (Expressions (N)); | |
854 | V := Uint_1; | |
855 | return; | |
856 | ||
857 | elsif Attribute_Name (N) = Name_Pred then | |
858 | R := First (Expressions (N)); | |
859 | V := Uint_Minus_1; | |
860 | return; | |
861 | end if; | |
862 | end if; | |
863 | ||
864 | R := N; | |
865 | V := Uint_0; | |
866 | end Compare_Decompose; | |
867 | ||
868 | ------------------- | |
869 | -- Compare_Fixup -- | |
870 | ------------------- | |
871 | ||
872 | function Compare_Fixup (N : Node_Id) return Node_Id is | |
873 | Indx : Node_Id; | |
874 | Xtyp : Entity_Id; | |
875 | Subs : Nat; | |
876 | ||
877 | begin | |
7a6de2e2 AC |
878 | -- Fixup only required for First/Last attribute reference |
879 | ||
996ae0b0 | 880 | if Nkind (N) = N_Attribute_Reference |
b69cd36a | 881 | and then Nam_In (Attribute_Name (N), Name_First, Name_Last) |
996ae0b0 RK |
882 | then |
883 | Xtyp := Etype (Prefix (N)); | |
884 | ||
885 | -- If we have no type, then just abandon the attempt to do | |
886 | -- a fixup, this is probably the result of some other error. | |
887 | ||
888 | if No (Xtyp) then | |
889 | return N; | |
890 | end if; | |
891 | ||
892 | -- Dereference an access type | |
893 | ||
894 | if Is_Access_Type (Xtyp) then | |
895 | Xtyp := Designated_Type (Xtyp); | |
896 | end if; | |
897 | ||
80298c3b AC |
898 | -- If we don't have an array type at this stage, something is |
899 | -- peculiar, e.g. another error, and we abandon the attempt at | |
900 | -- a fixup. | |
996ae0b0 RK |
901 | |
902 | if not Is_Array_Type (Xtyp) then | |
903 | return N; | |
904 | end if; | |
905 | ||
906 | -- Ignore unconstrained array, since bounds are not meaningful | |
907 | ||
908 | if not Is_Constrained (Xtyp) then | |
909 | return N; | |
910 | end if; | |
911 | ||
c3de5c4c ES |
912 | if Ekind (Xtyp) = E_String_Literal_Subtype then |
913 | if Attribute_Name (N) = Name_First then | |
914 | return String_Literal_Low_Bound (Xtyp); | |
5f44f0d4 | 915 | else |
80298c3b AC |
916 | return |
917 | Make_Integer_Literal (Sloc (N), | |
918 | Intval => Intval (String_Literal_Low_Bound (Xtyp)) + | |
919 | String_Literal_Length (Xtyp)); | |
c3de5c4c ES |
920 | end if; |
921 | end if; | |
922 | ||
996ae0b0 RK |
923 | -- Find correct index type |
924 | ||
925 | Indx := First_Index (Xtyp); | |
926 | ||
927 | if Present (Expressions (N)) then | |
928 | Subs := UI_To_Int (Expr_Value (First (Expressions (N)))); | |
929 | ||
930 | for J in 2 .. Subs loop | |
931 | Indx := Next_Index (Indx); | |
932 | end loop; | |
933 | end if; | |
934 | ||
935 | Xtyp := Etype (Indx); | |
936 | ||
937 | if Attribute_Name (N) = Name_First then | |
938 | return Type_Low_Bound (Xtyp); | |
7a6de2e2 | 939 | else |
996ae0b0 RK |
940 | return Type_High_Bound (Xtyp); |
941 | end if; | |
942 | end if; | |
943 | ||
944 | return N; | |
945 | end Compare_Fixup; | |
946 | ||
57036dcc ES |
947 | ---------------------------- |
948 | -- Is_Known_Valid_Operand -- | |
949 | ---------------------------- | |
950 | ||
951 | function Is_Known_Valid_Operand (Opnd : Node_Id) return Boolean is | |
952 | begin | |
953 | return (Is_Entity_Name (Opnd) | |
954 | and then | |
955 | (Is_Known_Valid (Entity (Opnd)) | |
956 | or else Ekind (Entity (Opnd)) = E_In_Parameter | |
957 | or else | |
958 | (Ekind (Entity (Opnd)) in Object_Kind | |
80298c3b | 959 | and then Present (Current_Value (Entity (Opnd)))))) |
57036dcc ES |
960 | or else Is_OK_Static_Expression (Opnd); |
961 | end Is_Known_Valid_Operand; | |
962 | ||
996ae0b0 RK |
963 | ------------------- |
964 | -- Is_Same_Value -- | |
965 | ------------------- | |
966 | ||
967 | function Is_Same_Value (L, R : Node_Id) return Boolean is | |
968 | Lf : constant Node_Id := Compare_Fixup (L); | |
969 | Rf : constant Node_Id := Compare_Fixup (R); | |
970 | ||
fbf5a39b | 971 | function Is_Same_Subscript (L, R : List_Id) return Boolean; |
57036dcc ES |
972 | -- L, R are the Expressions values from two attribute nodes for First |
973 | -- or Last attributes. Either may be set to No_List if no expressions | |
974 | -- are present (indicating subscript 1). The result is True if both | |
975 | -- expressions represent the same subscript (note one case is where | |
976 | -- one subscript is missing and the other is explicitly set to 1). | |
fbf5a39b AC |
977 | |
978 | ----------------------- | |
979 | -- Is_Same_Subscript -- | |
980 | ----------------------- | |
981 | ||
982 | function Is_Same_Subscript (L, R : List_Id) return Boolean is | |
983 | begin | |
984 | if L = No_List then | |
985 | if R = No_List then | |
986 | return True; | |
987 | else | |
988 | return Expr_Value (First (R)) = Uint_1; | |
989 | end if; | |
990 | ||
991 | else | |
992 | if R = No_List then | |
993 | return Expr_Value (First (L)) = Uint_1; | |
994 | else | |
995 | return Expr_Value (First (L)) = Expr_Value (First (R)); | |
996 | end if; | |
997 | end if; | |
998 | end Is_Same_Subscript; | |
999 | ||
1000 | -- Start of processing for Is_Same_Value | |
1001 | ||
996ae0b0 | 1002 | begin |
b49365b2 | 1003 | -- Values are the same if they refer to the same entity and the |
c800f862 RD |
1004 | -- entity is non-volatile. This does not however apply to Float |
1005 | -- types, since we may have two NaN values and they should never | |
1006 | -- compare equal. | |
996ae0b0 | 1007 | |
f08b2371 RD |
1008 | -- If the entity is a discriminant, the two expressions may be bounds |
1009 | -- of components of objects of the same discriminated type. The | |
1010 | -- values of the discriminants are not static, and therefore the | |
1011 | -- result is unknown. | |
1012 | ||
1013 | -- It would be better to comment individual branches of this test ??? | |
4fb0b3f0 | 1014 | |
b49365b2 RD |
1015 | if Nkind_In (Lf, N_Identifier, N_Expanded_Name) |
1016 | and then Nkind_In (Rf, N_Identifier, N_Expanded_Name) | |
996ae0b0 | 1017 | and then Entity (Lf) = Entity (Rf) |
4fb0b3f0 | 1018 | and then Ekind (Entity (Lf)) /= E_Discriminant |
b49365b2 | 1019 | and then Present (Entity (Lf)) |
fbf5a39b | 1020 | and then not Is_Floating_Point_Type (Etype (L)) |
c800f862 RD |
1021 | and then not Is_Volatile_Reference (L) |
1022 | and then not Is_Volatile_Reference (R) | |
996ae0b0 RK |
1023 | then |
1024 | return True; | |
1025 | ||
1026 | -- Or if they are compile time known and identical | |
1027 | ||
1028 | elsif Compile_Time_Known_Value (Lf) | |
1029 | and then | |
1030 | Compile_Time_Known_Value (Rf) | |
1031 | and then Expr_Value (Lf) = Expr_Value (Rf) | |
1032 | then | |
1033 | return True; | |
1034 | ||
b49365b2 RD |
1035 | -- False if Nkind of the two nodes is different for remaining cases |
1036 | ||
1037 | elsif Nkind (Lf) /= Nkind (Rf) then | |
1038 | return False; | |
1039 | ||
1040 | -- True if both 'First or 'Last values applying to the same entity | |
1041 | -- (first and last don't change even if value does). Note that we | |
1042 | -- need this even with the calls to Compare_Fixup, to handle the | |
1043 | -- case of unconstrained array attributes where Compare_Fixup | |
1044 | -- cannot find useful bounds. | |
996ae0b0 RK |
1045 | |
1046 | elsif Nkind (Lf) = N_Attribute_Reference | |
996ae0b0 | 1047 | and then Attribute_Name (Lf) = Attribute_Name (Rf) |
b69cd36a | 1048 | and then Nam_In (Attribute_Name (Lf), Name_First, Name_Last) |
b49365b2 RD |
1049 | and then Nkind_In (Prefix (Lf), N_Identifier, N_Expanded_Name) |
1050 | and then Nkind_In (Prefix (Rf), N_Identifier, N_Expanded_Name) | |
996ae0b0 | 1051 | and then Entity (Prefix (Lf)) = Entity (Prefix (Rf)) |
fbf5a39b | 1052 | and then Is_Same_Subscript (Expressions (Lf), Expressions (Rf)) |
996ae0b0 RK |
1053 | then |
1054 | return True; | |
1055 | ||
b49365b2 RD |
1056 | -- True if the same selected component from the same record |
1057 | ||
1058 | elsif Nkind (Lf) = N_Selected_Component | |
1059 | and then Selector_Name (Lf) = Selector_Name (Rf) | |
1060 | and then Is_Same_Value (Prefix (Lf), Prefix (Rf)) | |
1061 | then | |
1062 | return True; | |
1063 | ||
1064 | -- True if the same unary operator applied to the same operand | |
1065 | ||
1066 | elsif Nkind (Lf) in N_Unary_Op | |
1067 | and then Is_Same_Value (Right_Opnd (Lf), Right_Opnd (Rf)) | |
1068 | then | |
1069 | return True; | |
1070 | ||
8682d22c | 1071 | -- True if the same binary operator applied to the same operands |
b49365b2 RD |
1072 | |
1073 | elsif Nkind (Lf) in N_Binary_Op | |
1074 | and then Is_Same_Value (Left_Opnd (Lf), Left_Opnd (Rf)) | |
1075 | and then Is_Same_Value (Right_Opnd (Lf), Right_Opnd (Rf)) | |
1076 | then | |
1077 | return True; | |
1078 | ||
8682d22c | 1079 | -- All other cases, we can't tell, so return False |
996ae0b0 RK |
1080 | |
1081 | else | |
1082 | return False; | |
1083 | end if; | |
1084 | end Is_Same_Value; | |
1085 | ||
1086 | -- Start of processing for Compile_Time_Compare | |
1087 | ||
1088 | begin | |
af02a866 RD |
1089 | Diff.all := No_Uint; |
1090 | ||
37c1f923 AC |
1091 | -- In preanalysis mode, always return Unknown unless the expression |
1092 | -- is static. It is too early to be thinking we know the result of a | |
1093 | -- comparison, save that judgment for the full analysis. This is | |
1094 | -- particularly important in the case of pre and postconditions, which | |
1095 | -- otherwise can be prematurely collapsed into having True or False | |
1096 | -- conditions when this is inappropriate. | |
1097 | ||
1098 | if not (Full_Analysis | |
edab6088 | 1099 | or else (Is_OK_Static_Expression (L) |
db318f46 | 1100 | and then |
edab6088 | 1101 | Is_OK_Static_Expression (R))) |
37c1f923 | 1102 | then |
05b34c18 AC |
1103 | return Unknown; |
1104 | end if; | |
1105 | ||
07fc65c4 | 1106 | -- If either operand could raise constraint error, then we cannot |
a90bd866 | 1107 | -- know the result at compile time (since CE may be raised). |
07fc65c4 GB |
1108 | |
1109 | if not (Cannot_Raise_Constraint_Error (L) | |
1110 | and then | |
1111 | Cannot_Raise_Constraint_Error (R)) | |
1112 | then | |
1113 | return Unknown; | |
1114 | end if; | |
1115 | ||
1116 | -- Identical operands are most certainly equal | |
1117 | ||
996ae0b0 RK |
1118 | if L = R then |
1119 | return EQ; | |
08f52d9f | 1120 | end if; |
996ae0b0 | 1121 | |
93c3fca7 AC |
1122 | -- If expressions have no types, then do not attempt to determine if |
1123 | -- they are the same, since something funny is going on. One case in | |
1124 | -- which this happens is during generic template analysis, when bounds | |
1125 | -- are not fully analyzed. | |
996ae0b0 | 1126 | |
08f52d9f AC |
1127 | if No (Ltyp) or else No (Rtyp) then |
1128 | return Unknown; | |
1129 | end if; | |
1130 | ||
1131 | -- These get reset to the base type for the case of entities where | |
1132 | -- Is_Known_Valid is not set. This takes care of handling possible | |
1133 | -- invalid representations using the value of the base type, in | |
1134 | -- accordance with RM 13.9.1(10). | |
1135 | ||
1136 | Ltyp := Underlying_Type (Ltyp); | |
1137 | Rtyp := Underlying_Type (Rtyp); | |
1138 | ||
1139 | -- Same rationale as above, but for Underlying_Type instead of Etype | |
1140 | ||
1141 | if No (Ltyp) or else No (Rtyp) then | |
996ae0b0 | 1142 | return Unknown; |
08f52d9f | 1143 | end if; |
996ae0b0 | 1144 | |
0a3ec628 | 1145 | -- We do not attempt comparisons for packed arrays represented as |
93c3fca7 | 1146 | -- modular types, where the semantics of comparison is quite different. |
996ae0b0 | 1147 | |
08f52d9f | 1148 | if Is_Packed_Array_Impl_Type (Ltyp) |
93c3fca7 | 1149 | and then Is_Modular_Integer_Type (Ltyp) |
996ae0b0 RK |
1150 | then |
1151 | return Unknown; | |
1152 | ||
93c3fca7 | 1153 | -- For access types, the only time we know the result at compile time |
f61580d4 | 1154 | -- (apart from identical operands, which we handled already) is if we |
93c3fca7 AC |
1155 | -- know one operand is null and the other is not, or both operands are |
1156 | -- known null. | |
1157 | ||
1158 | elsif Is_Access_Type (Ltyp) then | |
1159 | if Known_Null (L) then | |
1160 | if Known_Null (R) then | |
1161 | return EQ; | |
1162 | elsif Known_Non_Null (R) then | |
1163 | return NE; | |
1164 | else | |
1165 | return Unknown; | |
1166 | end if; | |
1167 | ||
f61580d4 | 1168 | elsif Known_Non_Null (L) and then Known_Null (R) then |
93c3fca7 AC |
1169 | return NE; |
1170 | ||
1171 | else | |
1172 | return Unknown; | |
1173 | end if; | |
1174 | ||
996ae0b0 RK |
1175 | -- Case where comparison involves two compile time known values |
1176 | ||
1177 | elsif Compile_Time_Known_Value (L) | |
80298c3b AC |
1178 | and then |
1179 | Compile_Time_Known_Value (R) | |
996ae0b0 RK |
1180 | then |
1181 | -- For the floating-point case, we have to be a little careful, since | |
1182 | -- at compile time we are dealing with universal exact values, but at | |
1183 | -- runtime, these will be in non-exact target form. That's why the | |
1184 | -- returned results are LE and GE below instead of LT and GT. | |
1185 | ||
1186 | if Is_Floating_Point_Type (Ltyp) | |
1187 | or else | |
1188 | Is_Floating_Point_Type (Rtyp) | |
1189 | then | |
1190 | declare | |
1191 | Lo : constant Ureal := Expr_Value_R (L); | |
1192 | Hi : constant Ureal := Expr_Value_R (R); | |
996ae0b0 RK |
1193 | begin |
1194 | if Lo < Hi then | |
1195 | return LE; | |
1196 | elsif Lo = Hi then | |
1197 | return EQ; | |
1198 | else | |
1199 | return GE; | |
1200 | end if; | |
1201 | end; | |
1202 | ||
93c3fca7 AC |
1203 | -- For string types, we have two string literals and we proceed to |
1204 | -- compare them using the Ada style dictionary string comparison. | |
1205 | ||
1206 | elsif not Is_Scalar_Type (Ltyp) then | |
1207 | declare | |
1208 | Lstring : constant String_Id := Strval (Expr_Value_S (L)); | |
1209 | Rstring : constant String_Id := Strval (Expr_Value_S (R)); | |
1210 | Llen : constant Nat := String_Length (Lstring); | |
1211 | Rlen : constant Nat := String_Length (Rstring); | |
1212 | ||
1213 | begin | |
1214 | for J in 1 .. Nat'Min (Llen, Rlen) loop | |
1215 | declare | |
1216 | LC : constant Char_Code := Get_String_Char (Lstring, J); | |
1217 | RC : constant Char_Code := Get_String_Char (Rstring, J); | |
1218 | begin | |
1219 | if LC < RC then | |
1220 | return LT; | |
1221 | elsif LC > RC then | |
1222 | return GT; | |
1223 | end if; | |
1224 | end; | |
1225 | end loop; | |
1226 | ||
1227 | if Llen < Rlen then | |
1228 | return LT; | |
1229 | elsif Llen > Rlen then | |
1230 | return GT; | |
1231 | else | |
1232 | return EQ; | |
1233 | end if; | |
1234 | end; | |
1235 | ||
1236 | -- For remaining scalar cases we know exactly (note that this does | |
1237 | -- include the fixed-point case, where we know the run time integer | |
f61580d4 | 1238 | -- values now). |
996ae0b0 RK |
1239 | |
1240 | else | |
1241 | declare | |
1242 | Lo : constant Uint := Expr_Value (L); | |
1243 | Hi : constant Uint := Expr_Value (R); | |
996ae0b0 RK |
1244 | begin |
1245 | if Lo < Hi then | |
af02a866 | 1246 | Diff.all := Hi - Lo; |
996ae0b0 RK |
1247 | return LT; |
1248 | elsif Lo = Hi then | |
1249 | return EQ; | |
1250 | else | |
af02a866 | 1251 | Diff.all := Lo - Hi; |
996ae0b0 RK |
1252 | return GT; |
1253 | end if; | |
1254 | end; | |
1255 | end if; | |
1256 | ||
1257 | -- Cases where at least one operand is not known at compile time | |
1258 | ||
1259 | else | |
93c3fca7 | 1260 | -- Remaining checks apply only for discrete types |
29797f34 RD |
1261 | |
1262 | if not Is_Discrete_Type (Ltyp) | |
80298c3b AC |
1263 | or else |
1264 | not Is_Discrete_Type (Rtyp) | |
93c3fca7 AC |
1265 | then |
1266 | return Unknown; | |
1267 | end if; | |
1268 | ||
1269 | -- Defend against generic types, or actually any expressions that | |
1270 | -- contain a reference to a generic type from within a generic | |
1271 | -- template. We don't want to do any range analysis of such | |
1272 | -- expressions for two reasons. First, the bounds of a generic type | |
1273 | -- itself are junk and cannot be used for any kind of analysis. | |
1274 | -- Second, we may have a case where the range at run time is indeed | |
1275 | -- known, but we don't want to do compile time analysis in the | |
1276 | -- template based on that range since in an instance the value may be | |
1277 | -- static, and able to be elaborated without reference to the bounds | |
1278 | -- of types involved. As an example, consider: | |
1279 | ||
1280 | -- (F'Pos (F'Last) + 1) > Integer'Last | |
1281 | ||
1282 | -- The expression on the left side of > is Universal_Integer and thus | |
1283 | -- acquires the type Integer for evaluation at run time, and at run | |
1284 | -- time it is true that this condition is always False, but within | |
1285 | -- an instance F may be a type with a static range greater than the | |
1286 | -- range of Integer, and the expression statically evaluates to True. | |
1287 | ||
1288 | if References_Generic_Formal_Type (L) | |
1289 | or else | |
1290 | References_Generic_Formal_Type (R) | |
29797f34 RD |
1291 | then |
1292 | return Unknown; | |
1293 | end if; | |
1294 | ||
41a58113 | 1295 | -- Replace types by base types for the case of values which are not |
80298c3b AC |
1296 | -- known to have valid representations. This takes care of properly |
1297 | -- dealing with invalid representations. | |
1c7717c3 | 1298 | |
41a58113 RD |
1299 | if not Assume_Valid then |
1300 | if not (Is_Entity_Name (L) | |
1301 | and then (Is_Known_Valid (Entity (L)) | |
1302 | or else Assume_No_Invalid_Values)) | |
1303 | then | |
93c3fca7 | 1304 | Ltyp := Underlying_Type (Base_Type (Ltyp)); |
1c7717c3 AC |
1305 | end if; |
1306 | ||
41a58113 RD |
1307 | if not (Is_Entity_Name (R) |
1308 | and then (Is_Known_Valid (Entity (R)) | |
1309 | or else Assume_No_Invalid_Values)) | |
1310 | then | |
93c3fca7 | 1311 | Rtyp := Underlying_Type (Base_Type (Rtyp)); |
1c7717c3 AC |
1312 | end if; |
1313 | end if; | |
1314 | ||
a40ada7e RD |
1315 | -- First attempt is to decompose the expressions to extract a |
1316 | -- constant offset resulting from the use of any of the forms: | |
1317 | ||
1318 | -- expr + literal | |
1319 | -- expr - literal | |
1320 | -- typ'Succ (expr) | |
1321 | -- typ'Pred (expr) | |
1322 | ||
1323 | -- Then we see if the two expressions are the same value, and if so | |
1324 | -- the result is obtained by comparing the offsets. | |
1325 | ||
1326 | -- Note: the reason we do this test first is that it returns only | |
1327 | -- decisive results (with diff set), where other tests, like the | |
1328 | -- range test, may not be as so decisive. Consider for example | |
1329 | -- J .. J + 1. This code can conclude LT with a difference of 1, | |
1330 | -- even if the range of J is not known. | |
1331 | ||
22564ca9 EB |
1332 | declare |
1333 | Lnode : Node_Id; | |
1334 | Loffs : Uint; | |
1335 | Rnode : Node_Id; | |
1336 | Roffs : Uint; | |
a40ada7e | 1337 | |
22564ca9 EB |
1338 | begin |
1339 | Compare_Decompose (L, Lnode, Loffs); | |
1340 | Compare_Decompose (R, Rnode, Roffs); | |
a40ada7e | 1341 | |
22564ca9 EB |
1342 | if Is_Same_Value (Lnode, Rnode) then |
1343 | if Loffs = Roffs then | |
1344 | return EQ; | |
1345 | end if; | |
1346 | ||
1347 | -- When the offsets are not equal, we can go farther only if | |
1348 | -- the types are not modular (e.g. X < X + 1 is False if X is | |
1349 | -- the largest number). | |
0a3ec628 | 1350 | |
22564ca9 EB |
1351 | if not Is_Modular_Integer_Type (Ltyp) |
1352 | and then not Is_Modular_Integer_Type (Rtyp) | |
1353 | then | |
1354 | if Loffs < Roffs then | |
0a3ec628 AC |
1355 | Diff.all := Roffs - Loffs; |
1356 | return LT; | |
1357 | else | |
1358 | Diff.all := Loffs - Roffs; | |
1359 | return GT; | |
1360 | end if; | |
a40ada7e | 1361 | end if; |
22564ca9 EB |
1362 | end if; |
1363 | end; | |
a40ada7e RD |
1364 | |
1365 | -- Next, try range analysis and see if operand ranges are disjoint | |
c800f862 RD |
1366 | |
1367 | declare | |
1368 | LOK, ROK : Boolean; | |
1369 | LLo, LHi : Uint; | |
1370 | RLo, RHi : Uint; | |
1371 | ||
b6b5cca8 AC |
1372 | Single : Boolean; |
1373 | -- True if each range is a single point | |
1374 | ||
c800f862 RD |
1375 | begin |
1376 | Determine_Range (L, LOK, LLo, LHi, Assume_Valid); | |
1377 | Determine_Range (R, ROK, RLo, RHi, Assume_Valid); | |
1378 | ||
1379 | if LOK and ROK then | |
b6b5cca8 AC |
1380 | Single := (LLo = LHi) and then (RLo = RHi); |
1381 | ||
c800f862 | 1382 | if LHi < RLo then |
b6b5cca8 AC |
1383 | if Single and Assume_Valid then |
1384 | Diff.all := RLo - LLo; | |
1385 | end if; | |
1386 | ||
c800f862 RD |
1387 | return LT; |
1388 | ||
1389 | elsif RHi < LLo then | |
b6b5cca8 AC |
1390 | if Single and Assume_Valid then |
1391 | Diff.all := LLo - RLo; | |
1392 | end if; | |
1393 | ||
c800f862 RD |
1394 | return GT; |
1395 | ||
b6b5cca8 | 1396 | elsif Single and then LLo = RLo then |
e27b834b | 1397 | |
75ba322d AC |
1398 | -- If the range includes a single literal and we can assume |
1399 | -- validity then the result is known even if an operand is | |
1400 | -- not static. | |
e27b834b AC |
1401 | |
1402 | if Assume_Valid then | |
1403 | return EQ; | |
e27b834b AC |
1404 | else |
1405 | return Unknown; | |
1406 | end if; | |
c800f862 RD |
1407 | |
1408 | elsif LHi = RLo then | |
1409 | return LE; | |
1410 | ||
1411 | elsif RHi = LLo then | |
1412 | return GE; | |
57036dcc ES |
1413 | |
1414 | elsif not Is_Known_Valid_Operand (L) | |
1415 | and then not Assume_Valid | |
1416 | then | |
1417 | if Is_Same_Value (L, R) then | |
1418 | return EQ; | |
1419 | else | |
1420 | return Unknown; | |
1421 | end if; | |
c800f862 | 1422 | end if; |
f9ad6b62 | 1423 | |
2c1b72d7 AC |
1424 | -- If the range of either operand cannot be determined, nothing |
1425 | -- further can be inferred. | |
f9ad6b62 | 1426 | |
2c1b72d7 | 1427 | else |
f9ad6b62 | 1428 | return Unknown; |
c800f862 RD |
1429 | end if; |
1430 | end; | |
1431 | ||
996ae0b0 RK |
1432 | -- Here is where we check for comparisons against maximum bounds of |
1433 | -- types, where we know that no value can be outside the bounds of | |
1434 | -- the subtype. Note that this routine is allowed to assume that all | |
1435 | -- expressions are within their subtype bounds. Callers wishing to | |
1436 | -- deal with possibly invalid values must in any case take special | |
1437 | -- steps (e.g. conversions to larger types) to avoid this kind of | |
1438 | -- optimization, which is always considered to be valid. We do not | |
1439 | -- attempt this optimization with generic types, since the type | |
1440 | -- bounds may not be meaningful in this case. | |
1441 | ||
93c3fca7 | 1442 | -- We are in danger of an infinite recursion here. It does not seem |
fbf5a39b AC |
1443 | -- useful to go more than one level deep, so the parameter Rec is |
1444 | -- used to protect ourselves against this infinite recursion. | |
1445 | ||
29797f34 RD |
1446 | if not Rec then |
1447 | ||
80298c3b AC |
1448 | -- See if we can get a decisive check against one operand and a |
1449 | -- bound of the other operand (four possible tests here). Note | |
1450 | -- that we avoid testing junk bounds of a generic type. | |
93c3fca7 AC |
1451 | |
1452 | if not Is_Generic_Type (Rtyp) then | |
1453 | case Compile_Time_Compare (L, Type_Low_Bound (Rtyp), | |
1454 | Discard'Access, | |
1455 | Assume_Valid, Rec => True) | |
1456 | is | |
1457 | when LT => return LT; | |
1458 | when LE => return LE; | |
1459 | when EQ => return LE; | |
1460 | when others => null; | |
1461 | end case; | |
fbf5a39b | 1462 | |
93c3fca7 AC |
1463 | case Compile_Time_Compare (L, Type_High_Bound (Rtyp), |
1464 | Discard'Access, | |
1465 | Assume_Valid, Rec => True) | |
1466 | is | |
1467 | when GT => return GT; | |
1468 | when GE => return GE; | |
1469 | when EQ => return GE; | |
1470 | when others => null; | |
1471 | end case; | |
1472 | end if; | |
996ae0b0 | 1473 | |
93c3fca7 AC |
1474 | if not Is_Generic_Type (Ltyp) then |
1475 | case Compile_Time_Compare (Type_Low_Bound (Ltyp), R, | |
1476 | Discard'Access, | |
1477 | Assume_Valid, Rec => True) | |
1478 | is | |
1479 | when GT => return GT; | |
1480 | when GE => return GE; | |
1481 | when EQ => return GE; | |
1482 | when others => null; | |
1483 | end case; | |
996ae0b0 | 1484 | |
93c3fca7 AC |
1485 | case Compile_Time_Compare (Type_High_Bound (Ltyp), R, |
1486 | Discard'Access, | |
1487 | Assume_Valid, Rec => True) | |
1488 | is | |
1489 | when LT => return LT; | |
1490 | when LE => return LE; | |
1491 | when EQ => return LE; | |
1492 | when others => null; | |
1493 | end case; | |
1494 | end if; | |
996ae0b0 RK |
1495 | end if; |
1496 | ||
29797f34 RD |
1497 | -- Next attempt is to see if we have an entity compared with a |
1498 | -- compile time known value, where there is a current value | |
1499 | -- conditional for the entity which can tell us the result. | |
1500 | ||
1501 | declare | |
1502 | Var : Node_Id; | |
1503 | -- Entity variable (left operand) | |
1504 | ||
1505 | Val : Uint; | |
1506 | -- Value (right operand) | |
1507 | ||
1508 | Inv : Boolean; | |
1509 | -- If False, we have reversed the operands | |
1510 | ||
1511 | Op : Node_Kind; | |
1512 | -- Comparison operator kind from Get_Current_Value_Condition call | |
996ae0b0 | 1513 | |
29797f34 RD |
1514 | Opn : Node_Id; |
1515 | -- Value from Get_Current_Value_Condition call | |
1516 | ||
1517 | Opv : Uint; | |
1518 | -- Value of Opn | |
1519 | ||
1520 | Result : Compare_Result; | |
1521 | -- Known result before inversion | |
1522 | ||
1523 | begin | |
1524 | if Is_Entity_Name (L) | |
1525 | and then Compile_Time_Known_Value (R) | |
1526 | then | |
1527 | Var := L; | |
1528 | Val := Expr_Value (R); | |
1529 | Inv := False; | |
1530 | ||
1531 | elsif Is_Entity_Name (R) | |
1532 | and then Compile_Time_Known_Value (L) | |
1533 | then | |
1534 | Var := R; | |
1535 | Val := Expr_Value (L); | |
1536 | Inv := True; | |
1537 | ||
1538 | -- That was the last chance at finding a compile time result | |
996ae0b0 RK |
1539 | |
1540 | else | |
1541 | return Unknown; | |
1542 | end if; | |
29797f34 RD |
1543 | |
1544 | Get_Current_Value_Condition (Var, Op, Opn); | |
1545 | ||
1546 | -- That was the last chance, so if we got nothing return | |
1547 | ||
1548 | if No (Opn) then | |
1549 | return Unknown; | |
1550 | end if; | |
1551 | ||
1552 | Opv := Expr_Value (Opn); | |
1553 | ||
1554 | -- We got a comparison, so we might have something interesting | |
1555 | ||
1556 | -- Convert LE to LT and GE to GT, just so we have fewer cases | |
1557 | ||
1558 | if Op = N_Op_Le then | |
1559 | Op := N_Op_Lt; | |
1560 | Opv := Opv + 1; | |
af02a866 | 1561 | |
29797f34 RD |
1562 | elsif Op = N_Op_Ge then |
1563 | Op := N_Op_Gt; | |
1564 | Opv := Opv - 1; | |
1565 | end if; | |
1566 | ||
1567 | -- Deal with equality case | |
1568 | ||
1569 | if Op = N_Op_Eq then | |
1570 | if Val = Opv then | |
1571 | Result := EQ; | |
1572 | elsif Opv < Val then | |
1573 | Result := LT; | |
1574 | else | |
1575 | Result := GT; | |
1576 | end if; | |
1577 | ||
1578 | -- Deal with inequality case | |
1579 | ||
1580 | elsif Op = N_Op_Ne then | |
1581 | if Val = Opv then | |
1582 | Result := NE; | |
1583 | else | |
1584 | return Unknown; | |
1585 | end if; | |
1586 | ||
1587 | -- Deal with greater than case | |
1588 | ||
1589 | elsif Op = N_Op_Gt then | |
1590 | if Opv >= Val then | |
1591 | Result := GT; | |
1592 | elsif Opv = Val - 1 then | |
1593 | Result := GE; | |
1594 | else | |
1595 | return Unknown; | |
1596 | end if; | |
1597 | ||
1598 | -- Deal with less than case | |
1599 | ||
1600 | else pragma Assert (Op = N_Op_Lt); | |
1601 | if Opv <= Val then | |
1602 | Result := LT; | |
1603 | elsif Opv = Val + 1 then | |
1604 | Result := LE; | |
1605 | else | |
1606 | return Unknown; | |
1607 | end if; | |
1608 | end if; | |
1609 | ||
1610 | -- Deal with inverting result | |
1611 | ||
1612 | if Inv then | |
1613 | case Result is | |
1614 | when GT => return LT; | |
1615 | when GE => return LE; | |
1616 | when LT => return GT; | |
1617 | when LE => return GE; | |
1618 | when others => return Result; | |
1619 | end case; | |
1620 | end if; | |
1621 | ||
1622 | return Result; | |
996ae0b0 RK |
1623 | end; |
1624 | end if; | |
1625 | end Compile_Time_Compare; | |
1626 | ||
f44fe430 RD |
1627 | ------------------------------- |
1628 | -- Compile_Time_Known_Bounds -- | |
1629 | ------------------------------- | |
1630 | ||
1631 | function Compile_Time_Known_Bounds (T : Entity_Id) return Boolean is | |
1632 | Indx : Node_Id; | |
1633 | Typ : Entity_Id; | |
1634 | ||
1635 | begin | |
f5f6d8d7 | 1636 | if T = Any_Composite or else not Is_Array_Type (T) then |
f44fe430 RD |
1637 | return False; |
1638 | end if; | |
1639 | ||
1640 | Indx := First_Index (T); | |
1641 | while Present (Indx) loop | |
1642 | Typ := Underlying_Type (Etype (Indx)); | |
93c3fca7 AC |
1643 | |
1644 | -- Never look at junk bounds of a generic type | |
1645 | ||
1646 | if Is_Generic_Type (Typ) then | |
1647 | return False; | |
1648 | end if; | |
1649 | ||
1650 | -- Otherwise check bounds for compile time known | |
1651 | ||
f44fe430 RD |
1652 | if not Compile_Time_Known_Value (Type_Low_Bound (Typ)) then |
1653 | return False; | |
1654 | elsif not Compile_Time_Known_Value (Type_High_Bound (Typ)) then | |
1655 | return False; | |
1656 | else | |
1657 | Next_Index (Indx); | |
1658 | end if; | |
1659 | end loop; | |
1660 | ||
1661 | return True; | |
1662 | end Compile_Time_Known_Bounds; | |
1663 | ||
996ae0b0 RK |
1664 | ------------------------------ |
1665 | -- Compile_Time_Known_Value -- | |
1666 | ------------------------------ | |
1667 | ||
6c3c671e | 1668 | function Compile_Time_Known_Value (Op : Node_Id) return Boolean is |
07fc65c4 GB |
1669 | K : constant Node_Kind := Nkind (Op); |
1670 | CV_Ent : CV_Entry renames CV_Cache (Nat (Op) mod CV_Cache_Size); | |
996ae0b0 RK |
1671 | |
1672 | begin | |
1673 | -- Never known at compile time if bad type or raises constraint error | |
ee2ba856 | 1674 | -- or empty (latter case occurs only as a result of a previous error). |
996ae0b0 | 1675 | |
ee2ba856 AC |
1676 | if No (Op) then |
1677 | Check_Error_Detected; | |
1678 | return False; | |
1679 | ||
1680 | elsif Op = Error | |
996ae0b0 RK |
1681 | or else Etype (Op) = Any_Type |
1682 | or else Raises_Constraint_Error (Op) | |
1683 | then | |
1684 | return False; | |
1685 | end if; | |
1686 | ||
1687 | -- If we have an entity name, then see if it is the name of a constant | |
1688 | -- and if so, test the corresponding constant value, or the name of | |
1689 | -- an enumeration literal, which is always a constant. | |
1690 | ||
1691 | if Present (Etype (Op)) and then Is_Entity_Name (Op) then | |
1692 | declare | |
1693 | E : constant Entity_Id := Entity (Op); | |
1694 | V : Node_Id; | |
1695 | ||
1696 | begin | |
1697 | -- Never known at compile time if it is a packed array value. | |
1698 | -- We might want to try to evaluate these at compile time one | |
1699 | -- day, but we do not make that attempt now. | |
1700 | ||
8ca597af | 1701 | if Is_Packed_Array_Impl_Type (Etype (Op)) then |
996ae0b0 RK |
1702 | return False; |
1703 | end if; | |
1704 | ||
1705 | if Ekind (E) = E_Enumeration_Literal then | |
1706 | return True; | |
1707 | ||
5114f3ff | 1708 | elsif Ekind (E) = E_Constant then |
996ae0b0 RK |
1709 | V := Constant_Value (E); |
1710 | return Present (V) and then Compile_Time_Known_Value (V); | |
1711 | end if; | |
1712 | end; | |
1713 | ||
1714 | -- We have a value, see if it is compile time known | |
1715 | ||
1716 | else | |
07fc65c4 | 1717 | -- Integer literals are worth storing in the cache |
996ae0b0 | 1718 | |
07fc65c4 GB |
1719 | if K = N_Integer_Literal then |
1720 | CV_Ent.N := Op; | |
1721 | CV_Ent.V := Intval (Op); | |
1722 | return True; | |
1723 | ||
1724 | -- Other literals and NULL are known at compile time | |
1725 | ||
1726 | elsif | |
80298c3b AC |
1727 | Nkind_In (K, N_Character_Literal, |
1728 | N_Real_Literal, | |
1729 | N_String_Literal, | |
1730 | N_Null) | |
996ae0b0 RK |
1731 | then |
1732 | return True; | |
07fc65c4 | 1733 | end if; |
996ae0b0 | 1734 | end if; |
07fc65c4 GB |
1735 | |
1736 | -- If we fall through, not known at compile time | |
1737 | ||
1738 | return False; | |
1739 | ||
1740 | -- If we get an exception while trying to do this test, then some error | |
1741 | -- has occurred, and we simply say that the value is not known after all | |
1742 | ||
1743 | exception | |
1744 | when others => | |
1745 | return False; | |
996ae0b0 RK |
1746 | end Compile_Time_Known_Value; |
1747 | ||
1748 | -------------------------------------- | |
1749 | -- Compile_Time_Known_Value_Or_Aggr -- | |
1750 | -------------------------------------- | |
1751 | ||
1752 | function Compile_Time_Known_Value_Or_Aggr (Op : Node_Id) return Boolean is | |
1753 | begin | |
1754 | -- If we have an entity name, then see if it is the name of a constant | |
1755 | -- and if so, test the corresponding constant value, or the name of | |
1756 | -- an enumeration literal, which is always a constant. | |
1757 | ||
1758 | if Is_Entity_Name (Op) then | |
1759 | declare | |
1760 | E : constant Entity_Id := Entity (Op); | |
1761 | V : Node_Id; | |
1762 | ||
1763 | begin | |
1764 | if Ekind (E) = E_Enumeration_Literal then | |
1765 | return True; | |
1766 | ||
1767 | elsif Ekind (E) /= E_Constant then | |
1768 | return False; | |
1769 | ||
1770 | else | |
1771 | V := Constant_Value (E); | |
1772 | return Present (V) | |
1773 | and then Compile_Time_Known_Value_Or_Aggr (V); | |
1774 | end if; | |
1775 | end; | |
1776 | ||
1777 | -- We have a value, see if it is compile time known | |
1778 | ||
1779 | else | |
1780 | if Compile_Time_Known_Value (Op) then | |
1781 | return True; | |
1782 | ||
1783 | elsif Nkind (Op) = N_Aggregate then | |
1784 | ||
1785 | if Present (Expressions (Op)) then | |
1786 | declare | |
1787 | Expr : Node_Id; | |
996ae0b0 RK |
1788 | begin |
1789 | Expr := First (Expressions (Op)); | |
1790 | while Present (Expr) loop | |
1791 | if not Compile_Time_Known_Value_Or_Aggr (Expr) then | |
1792 | return False; | |
80298c3b AC |
1793 | else |
1794 | Next (Expr); | |
996ae0b0 | 1795 | end if; |
996ae0b0 RK |
1796 | end loop; |
1797 | end; | |
1798 | end if; | |
1799 | ||
1800 | if Present (Component_Associations (Op)) then | |
1801 | declare | |
1802 | Cass : Node_Id; | |
1803 | ||
1804 | begin | |
1805 | Cass := First (Component_Associations (Op)); | |
1806 | while Present (Cass) loop | |
1807 | if not | |
1808 | Compile_Time_Known_Value_Or_Aggr (Expression (Cass)) | |
1809 | then | |
1810 | return False; | |
1811 | end if; | |
1812 | ||
1813 | Next (Cass); | |
1814 | end loop; | |
1815 | end; | |
1816 | end if; | |
1817 | ||
1818 | return True; | |
1819 | ||
1820 | -- All other types of values are not known at compile time | |
1821 | ||
1822 | else | |
1823 | return False; | |
1824 | end if; | |
1825 | ||
1826 | end if; | |
1827 | end Compile_Time_Known_Value_Or_Aggr; | |
1828 | ||
6c3c671e AC |
1829 | --------------------------------------- |
1830 | -- CRT_Safe_Compile_Time_Known_Value -- | |
1831 | --------------------------------------- | |
1832 | ||
1833 | function CRT_Safe_Compile_Time_Known_Value (Op : Node_Id) return Boolean is | |
1834 | begin | |
1835 | if (Configurable_Run_Time_Mode or No_Run_Time_Mode) | |
1836 | and then not Is_OK_Static_Expression (Op) | |
1837 | then | |
1838 | return False; | |
1839 | else | |
1840 | return Compile_Time_Known_Value (Op); | |
1841 | end if; | |
1842 | end CRT_Safe_Compile_Time_Known_Value; | |
1843 | ||
996ae0b0 RK |
1844 | ----------------- |
1845 | -- Eval_Actual -- | |
1846 | ----------------- | |
1847 | ||
1848 | -- This is only called for actuals of functions that are not predefined | |
1849 | -- operators (which have already been rewritten as operators at this | |
1850 | -- stage), so the call can never be folded, and all that needs doing for | |
1851 | -- the actual is to do the check for a non-static context. | |
1852 | ||
1853 | procedure Eval_Actual (N : Node_Id) is | |
1854 | begin | |
1855 | Check_Non_Static_Context (N); | |
1856 | end Eval_Actual; | |
1857 | ||
1858 | -------------------- | |
1859 | -- Eval_Allocator -- | |
1860 | -------------------- | |
1861 | ||
1862 | -- Allocators are never static, so all we have to do is to do the | |
1863 | -- check for a non-static context if an expression is present. | |
1864 | ||
1865 | procedure Eval_Allocator (N : Node_Id) is | |
1866 | Expr : constant Node_Id := Expression (N); | |
996ae0b0 RK |
1867 | begin |
1868 | if Nkind (Expr) = N_Qualified_Expression then | |
1869 | Check_Non_Static_Context (Expression (Expr)); | |
1870 | end if; | |
1871 | end Eval_Allocator; | |
1872 | ||
1873 | ------------------------ | |
1874 | -- Eval_Arithmetic_Op -- | |
1875 | ------------------------ | |
1876 | ||
1877 | -- Arithmetic operations are static functions, so the result is static | |
1878 | -- if both operands are static (RM 4.9(7), 4.9(20)). | |
1879 | ||
1880 | procedure Eval_Arithmetic_Op (N : Node_Id) is | |
1881 | Left : constant Node_Id := Left_Opnd (N); | |
1882 | Right : constant Node_Id := Right_Opnd (N); | |
1883 | Ltype : constant Entity_Id := Etype (Left); | |
1884 | Rtype : constant Entity_Id := Etype (Right); | |
d7567964 | 1885 | Otype : Entity_Id := Empty; |
996ae0b0 RK |
1886 | Stat : Boolean; |
1887 | Fold : Boolean; | |
1888 | ||
1889 | begin | |
1890 | -- If not foldable we are done | |
1891 | ||
1892 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
1893 | ||
1894 | if not Fold then | |
1895 | return; | |
1896 | end if; | |
1897 | ||
6c3c671e AC |
1898 | -- Otherwise attempt to fold |
1899 | ||
d7567964 TQ |
1900 | if Is_Universal_Numeric_Type (Etype (Left)) |
1901 | and then | |
1902 | Is_Universal_Numeric_Type (Etype (Right)) | |
602a7ec0 | 1903 | then |
d7567964 | 1904 | Otype := Find_Universal_Operator_Type (N); |
602a7ec0 AC |
1905 | end if; |
1906 | ||
996ae0b0 RK |
1907 | -- Fold for cases where both operands are of integer type |
1908 | ||
1909 | if Is_Integer_Type (Ltype) and then Is_Integer_Type (Rtype) then | |
1910 | declare | |
1911 | Left_Int : constant Uint := Expr_Value (Left); | |
1912 | Right_Int : constant Uint := Expr_Value (Right); | |
1913 | Result : Uint; | |
1914 | ||
1915 | begin | |
1916 | case Nkind (N) is | |
996ae0b0 RK |
1917 | when N_Op_Add => |
1918 | Result := Left_Int + Right_Int; | |
1919 | ||
1920 | when N_Op_Subtract => | |
1921 | Result := Left_Int - Right_Int; | |
1922 | ||
1923 | when N_Op_Multiply => | |
1924 | if OK_Bits | |
1925 | (N, UI_From_Int | |
1926 | (Num_Bits (Left_Int) + Num_Bits (Right_Int))) | |
1927 | then | |
1928 | Result := Left_Int * Right_Int; | |
1929 | else | |
1930 | Result := Left_Int; | |
1931 | end if; | |
1932 | ||
1933 | when N_Op_Divide => | |
1934 | ||
1935 | -- The exception Constraint_Error is raised by integer | |
1936 | -- division, rem and mod if the right operand is zero. | |
1937 | ||
1938 | if Right_Int = 0 then | |
520c0201 AC |
1939 | |
1940 | -- When SPARK_Mode is On, force a warning instead of | |
1941 | -- an error in that case, as this likely corresponds | |
1942 | -- to deactivated code. | |
1943 | ||
996ae0b0 | 1944 | Apply_Compile_Time_Constraint_Error |
80298c3b | 1945 | (N, "division by zero", CE_Divide_By_Zero, |
520c0201 | 1946 | Warn => not Stat or SPARK_Mode = On); |
edab6088 | 1947 | Set_Raises_Constraint_Error (N); |
996ae0b0 | 1948 | return; |
fbf5a39b | 1949 | |
edab6088 RD |
1950 | -- Otherwise we can do the division |
1951 | ||
996ae0b0 RK |
1952 | else |
1953 | Result := Left_Int / Right_Int; | |
1954 | end if; | |
1955 | ||
1956 | when N_Op_Mod => | |
1957 | ||
1958 | -- The exception Constraint_Error is raised by integer | |
1959 | -- division, rem and mod if the right operand is zero. | |
1960 | ||
1961 | if Right_Int = 0 then | |
520c0201 AC |
1962 | |
1963 | -- When SPARK_Mode is On, force a warning instead of | |
1964 | -- an error in that case, as this likely corresponds | |
1965 | -- to deactivated code. | |
1966 | ||
996ae0b0 | 1967 | Apply_Compile_Time_Constraint_Error |
80298c3b | 1968 | (N, "mod with zero divisor", CE_Divide_By_Zero, |
520c0201 | 1969 | Warn => not Stat or SPARK_Mode = On); |
996ae0b0 | 1970 | return; |
520c0201 | 1971 | |
996ae0b0 RK |
1972 | else |
1973 | Result := Left_Int mod Right_Int; | |
1974 | end if; | |
1975 | ||
1976 | when N_Op_Rem => | |
1977 | ||
1978 | -- The exception Constraint_Error is raised by integer | |
1979 | -- division, rem and mod if the right operand is zero. | |
1980 | ||
1981 | if Right_Int = 0 then | |
520c0201 AC |
1982 | |
1983 | -- When SPARK_Mode is On, force a warning instead of | |
1984 | -- an error in that case, as this likely corresponds | |
1985 | -- to deactivated code. | |
1986 | ||
996ae0b0 | 1987 | Apply_Compile_Time_Constraint_Error |
80298c3b | 1988 | (N, "rem with zero divisor", CE_Divide_By_Zero, |
520c0201 | 1989 | Warn => not Stat or SPARK_Mode = On); |
996ae0b0 | 1990 | return; |
fbf5a39b | 1991 | |
996ae0b0 RK |
1992 | else |
1993 | Result := Left_Int rem Right_Int; | |
1994 | end if; | |
1995 | ||
1996 | when others => | |
1997 | raise Program_Error; | |
1998 | end case; | |
1999 | ||
2000 | -- Adjust the result by the modulus if the type is a modular type | |
2001 | ||
2002 | if Is_Modular_Integer_Type (Ltype) then | |
2003 | Result := Result mod Modulus (Ltype); | |
82c80734 RD |
2004 | |
2005 | -- For a signed integer type, check non-static overflow | |
2006 | ||
2007 | elsif (not Stat) and then Is_Signed_Integer_Type (Ltype) then | |
2008 | declare | |
2009 | BT : constant Entity_Id := Base_Type (Ltype); | |
2010 | Lo : constant Uint := Expr_Value (Type_Low_Bound (BT)); | |
2011 | Hi : constant Uint := Expr_Value (Type_High_Bound (BT)); | |
2012 | begin | |
2013 | if Result < Lo or else Result > Hi then | |
2014 | Apply_Compile_Time_Constraint_Error | |
324ac540 | 2015 | (N, "value not in range of }??", |
82c80734 RD |
2016 | CE_Overflow_Check_Failed, |
2017 | Ent => BT); | |
2018 | return; | |
2019 | end if; | |
2020 | end; | |
996ae0b0 RK |
2021 | end if; |
2022 | ||
82c80734 RD |
2023 | -- If we get here we can fold the result |
2024 | ||
fbf5a39b | 2025 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
2026 | end; |
2027 | ||
d7567964 TQ |
2028 | -- Cases where at least one operand is a real. We handle the cases of |
2029 | -- both reals, or mixed/real integer cases (the latter happen only for | |
2030 | -- divide and multiply, and the result is always real). | |
996ae0b0 RK |
2031 | |
2032 | elsif Is_Real_Type (Ltype) or else Is_Real_Type (Rtype) then | |
2033 | declare | |
2034 | Left_Real : Ureal; | |
2035 | Right_Real : Ureal; | |
2036 | Result : Ureal; | |
2037 | ||
2038 | begin | |
2039 | if Is_Real_Type (Ltype) then | |
2040 | Left_Real := Expr_Value_R (Left); | |
2041 | else | |
2042 | Left_Real := UR_From_Uint (Expr_Value (Left)); | |
2043 | end if; | |
2044 | ||
2045 | if Is_Real_Type (Rtype) then | |
2046 | Right_Real := Expr_Value_R (Right); | |
2047 | else | |
2048 | Right_Real := UR_From_Uint (Expr_Value (Right)); | |
2049 | end if; | |
2050 | ||
2051 | if Nkind (N) = N_Op_Add then | |
2052 | Result := Left_Real + Right_Real; | |
2053 | ||
2054 | elsif Nkind (N) = N_Op_Subtract then | |
2055 | Result := Left_Real - Right_Real; | |
2056 | ||
2057 | elsif Nkind (N) = N_Op_Multiply then | |
2058 | Result := Left_Real * Right_Real; | |
2059 | ||
2060 | else pragma Assert (Nkind (N) = N_Op_Divide); | |
2061 | if UR_Is_Zero (Right_Real) then | |
2062 | Apply_Compile_Time_Constraint_Error | |
07fc65c4 | 2063 | (N, "division by zero", CE_Divide_By_Zero); |
996ae0b0 RK |
2064 | return; |
2065 | end if; | |
2066 | ||
2067 | Result := Left_Real / Right_Real; | |
2068 | end if; | |
2069 | ||
fbf5a39b | 2070 | Fold_Ureal (N, Result, Stat); |
996ae0b0 RK |
2071 | end; |
2072 | end if; | |
d7567964 TQ |
2073 | |
2074 | -- If the operator was resolved to a specific type, make sure that type | |
2075 | -- is frozen even if the expression is folded into a literal (which has | |
2076 | -- a universal type). | |
2077 | ||
2078 | if Present (Otype) then | |
2079 | Freeze_Before (N, Otype); | |
2080 | end if; | |
996ae0b0 RK |
2081 | end Eval_Arithmetic_Op; |
2082 | ||
2083 | ---------------------------- | |
2084 | -- Eval_Character_Literal -- | |
2085 | ---------------------------- | |
2086 | ||
a90bd866 | 2087 | -- Nothing to be done |
996ae0b0 RK |
2088 | |
2089 | procedure Eval_Character_Literal (N : Node_Id) is | |
07fc65c4 | 2090 | pragma Warnings (Off, N); |
996ae0b0 RK |
2091 | begin |
2092 | null; | |
2093 | end Eval_Character_Literal; | |
2094 | ||
c01a9391 AC |
2095 | --------------- |
2096 | -- Eval_Call -- | |
2097 | --------------- | |
2098 | ||
2099 | -- Static function calls are either calls to predefined operators | |
2100 | -- with static arguments, or calls to functions that rename a literal. | |
2101 | -- Only the latter case is handled here, predefined operators are | |
2102 | -- constant-folded elsewhere. | |
29797f34 | 2103 | |
c01a9391 AC |
2104 | -- If the function is itself inherited (see 7423-001) the literal of |
2105 | -- the parent type must be explicitly converted to the return type | |
2106 | -- of the function. | |
2107 | ||
2108 | procedure Eval_Call (N : Node_Id) is | |
2109 | Loc : constant Source_Ptr := Sloc (N); | |
2110 | Typ : constant Entity_Id := Etype (N); | |
2111 | Lit : Entity_Id; | |
2112 | ||
2113 | begin | |
2114 | if Nkind (N) = N_Function_Call | |
2115 | and then No (Parameter_Associations (N)) | |
2116 | and then Is_Entity_Name (Name (N)) | |
2117 | and then Present (Alias (Entity (Name (N)))) | |
2118 | and then Is_Enumeration_Type (Base_Type (Typ)) | |
2119 | then | |
b81a5940 | 2120 | Lit := Ultimate_Alias (Entity (Name (N))); |
c01a9391 AC |
2121 | |
2122 | if Ekind (Lit) = E_Enumeration_Literal then | |
2123 | if Base_Type (Etype (Lit)) /= Base_Type (Typ) then | |
2124 | Rewrite | |
2125 | (N, Convert_To (Typ, New_Occurrence_Of (Lit, Loc))); | |
2126 | else | |
2127 | Rewrite (N, New_Occurrence_Of (Lit, Loc)); | |
2128 | end if; | |
2129 | ||
2130 | Resolve (N, Typ); | |
2131 | end if; | |
2132 | end if; | |
2133 | end Eval_Call; | |
2134 | ||
19d846a0 RD |
2135 | -------------------------- |
2136 | -- Eval_Case_Expression -- | |
2137 | -------------------------- | |
2138 | ||
ed7b9d6e | 2139 | -- A conditional expression is static if all its conditions and dependent |
edab6088 RD |
2140 | -- expressions are static. Note that we do not care if the dependent |
2141 | -- expressions raise CE, except for the one that will be selected. | |
19d846a0 RD |
2142 | |
2143 | procedure Eval_Case_Expression (N : Node_Id) is | |
edab6088 RD |
2144 | Alt : Node_Id; |
2145 | Choice : Node_Id; | |
19d846a0 RD |
2146 | |
2147 | begin | |
edab6088 | 2148 | Set_Is_Static_Expression (N, False); |
ed7b9d6e | 2149 | |
edab6088 | 2150 | if not Is_Static_Expression (Expression (N)) then |
ed7b9d6e | 2151 | Check_Non_Static_Context (Expression (N)); |
edab6088 | 2152 | return; |
ed7b9d6e | 2153 | end if; |
19d846a0 | 2154 | |
edab6088 RD |
2155 | -- First loop, make sure all the alternatives are static expressions |
2156 | -- none of which raise Constraint_Error. We make the constraint error | |
2157 | -- check because part of the legality condition for a correct static | |
2158 | -- case expression is that the cases are covered, like any other case | |
2159 | -- expression. And we can't do that if any of the conditions raise an | |
2160 | -- exception, so we don't even try to evaluate if that is the case. | |
2161 | ||
19d846a0 | 2162 | Alt := First (Alternatives (N)); |
edab6088 | 2163 | while Present (Alt) loop |
ed7b9d6e | 2164 | |
edab6088 RD |
2165 | -- The expression must be static, but we don't care at this stage |
2166 | -- if it raises Constraint_Error (the alternative might not match, | |
2167 | -- in which case the expression is statically unevaluated anyway). | |
ed7b9d6e | 2168 | |
edab6088 RD |
2169 | if not Is_Static_Expression (Expression (Alt)) then |
2170 | Check_Non_Static_Context (Expression (Alt)); | |
2171 | return; | |
2172 | end if; | |
ed7b9d6e | 2173 | |
edab6088 RD |
2174 | -- The choices of a case always have to be static, and cannot raise |
2175 | -- an exception. If this condition is not met, then the expression | |
2176 | -- is plain illegal, so just abandon evaluation attempts. No need | |
2177 | -- to check non-static context when we have something illegal anyway. | |
ed7b9d6e | 2178 | |
edab6088 RD |
2179 | if not Is_OK_Static_Choice_List (Discrete_Choices (Alt)) then |
2180 | return; | |
ed7b9d6e AC |
2181 | end if; |
2182 | ||
19d846a0 | 2183 | Next (Alt); |
edab6088 | 2184 | end loop; |
ed7b9d6e | 2185 | |
edab6088 RD |
2186 | -- OK, if the above loop gets through it means that all choices are OK |
2187 | -- static (don't raise exceptions), so the whole case is static, and we | |
2188 | -- can find the matching alternative. | |
2189 | ||
2190 | Set_Is_Static_Expression (N); | |
2191 | ||
2192 | -- Now to deal with propagating a possible constraint error | |
2193 | ||
2194 | -- If the selecting expression raises CE, propagate and we are done | |
2195 | ||
2196 | if Raises_Constraint_Error (Expression (N)) then | |
2197 | Set_Raises_Constraint_Error (N); | |
2198 | ||
2199 | -- Otherwise we need to check the alternatives to find the matching | |
2200 | -- one. CE's in other than the matching one are not relevant. But we | |
2201 | -- do need to check the matching one. Unlike the first loop, we do not | |
2202 | -- have to go all the way through, when we find the matching one, quit. | |
ed7b9d6e AC |
2203 | |
2204 | else | |
edab6088 RD |
2205 | Alt := First (Alternatives (N)); |
2206 | Search : loop | |
2207 | ||
4bd4bb7f | 2208 | -- We must find a match among the alternatives. If not, this must |
edab6088 RD |
2209 | -- be due to other errors, so just ignore, leaving as non-static. |
2210 | ||
2211 | if No (Alt) then | |
2212 | Set_Is_Static_Expression (N, False); | |
2213 | return; | |
2214 | end if; | |
2215 | ||
2216 | -- Otherwise loop through choices of this alternative | |
2217 | ||
2218 | Choice := First (Discrete_Choices (Alt)); | |
2219 | while Present (Choice) loop | |
2220 | ||
2221 | -- If we find a matching choice, then the Expression of this | |
2222 | -- alternative replaces N (Raises_Constraint_Error flag is | |
2223 | -- included, so we don't have to special case that). | |
2224 | ||
2225 | if Choice_Matches (Expression (N), Choice) = Match then | |
2226 | Rewrite (N, Relocate_Node (Expression (Alt))); | |
2227 | return; | |
2228 | end if; | |
2229 | ||
2230 | Next (Choice); | |
2231 | end loop; | |
2232 | ||
2233 | Next (Alt); | |
2234 | end loop Search; | |
ed7b9d6e | 2235 | end if; |
19d846a0 RD |
2236 | end Eval_Case_Expression; |
2237 | ||
996ae0b0 RK |
2238 | ------------------------ |
2239 | -- Eval_Concatenation -- | |
2240 | ------------------------ | |
2241 | ||
3996951a TQ |
2242 | -- Concatenation is a static function, so the result is static if both |
2243 | -- operands are static (RM 4.9(7), 4.9(21)). | |
996ae0b0 RK |
2244 | |
2245 | procedure Eval_Concatenation (N : Node_Id) is | |
f91b40db GB |
2246 | Left : constant Node_Id := Left_Opnd (N); |
2247 | Right : constant Node_Id := Right_Opnd (N); | |
2248 | C_Typ : constant Entity_Id := Root_Type (Component_Type (Etype (N))); | |
996ae0b0 RK |
2249 | Stat : Boolean; |
2250 | Fold : Boolean; | |
996ae0b0 RK |
2251 | |
2252 | begin | |
3996951a TQ |
2253 | -- Concatenation is never static in Ada 83, so if Ada 83 check operand |
2254 | -- non-static context. | |
996ae0b0 | 2255 | |
0ab80019 | 2256 | if Ada_Version = Ada_83 |
996ae0b0 RK |
2257 | and then Comes_From_Source (N) |
2258 | then | |
2259 | Check_Non_Static_Context (Left); | |
2260 | Check_Non_Static_Context (Right); | |
2261 | return; | |
2262 | end if; | |
2263 | ||
2264 | -- If not foldable we are done. In principle concatenation that yields | |
2265 | -- any string type is static (i.e. an array type of character types). | |
2266 | -- However, character types can include enumeration literals, and | |
2267 | -- concatenation in that case cannot be described by a literal, so we | |
2268 | -- only consider the operation static if the result is an array of | |
2269 | -- (a descendant of) a predefined character type. | |
2270 | ||
2271 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
2272 | ||
3996951a | 2273 | if not (Is_Standard_Character_Type (C_Typ) and then Fold) then |
996ae0b0 RK |
2274 | Set_Is_Static_Expression (N, False); |
2275 | return; | |
2276 | end if; | |
2277 | ||
82c80734 | 2278 | -- Compile time string concatenation |
996ae0b0 | 2279 | |
3996951a TQ |
2280 | -- ??? Note that operands that are aggregates can be marked as static, |
2281 | -- so we should attempt at a later stage to fold concatenations with | |
2282 | -- such aggregates. | |
996ae0b0 RK |
2283 | |
2284 | declare | |
b54ddf5a BD |
2285 | Left_Str : constant Node_Id := Get_String_Val (Left); |
2286 | Left_Len : Nat; | |
2287 | Right_Str : constant Node_Id := Get_String_Val (Right); | |
2288 | Folded_Val : String_Id; | |
996ae0b0 RK |
2289 | |
2290 | begin | |
2291 | -- Establish new string literal, and store left operand. We make | |
2292 | -- sure to use the special Start_String that takes an operand if | |
2293 | -- the left operand is a string literal. Since this is optimized | |
2294 | -- in the case where that is the most recently created string | |
2295 | -- literal, we ensure efficient time/space behavior for the | |
2296 | -- case of a concatenation of a series of string literals. | |
2297 | ||
2298 | if Nkind (Left_Str) = N_String_Literal then | |
c8307596 | 2299 | Left_Len := String_Length (Strval (Left_Str)); |
b54ddf5a BD |
2300 | |
2301 | -- If the left operand is the empty string, and the right operand | |
2302 | -- is a string literal (the case of "" & "..."), the result is the | |
2303 | -- value of the right operand. This optimization is important when | |
2304 | -- Is_Folded_In_Parser, to avoid copying an enormous right | |
2305 | -- operand. | |
2306 | ||
2307 | if Left_Len = 0 and then Nkind (Right_Str) = N_String_Literal then | |
2308 | Folded_Val := Strval (Right_Str); | |
2309 | else | |
2310 | Start_String (Strval (Left_Str)); | |
2311 | end if; | |
2312 | ||
996ae0b0 RK |
2313 | else |
2314 | Start_String; | |
82c80734 | 2315 | Store_String_Char (UI_To_CC (Char_Literal_Value (Left_Str))); |
f91b40db | 2316 | Left_Len := 1; |
996ae0b0 RK |
2317 | end if; |
2318 | ||
b54ddf5a BD |
2319 | -- Now append the characters of the right operand, unless we |
2320 | -- optimized the "" & "..." case above. | |
996ae0b0 RK |
2321 | |
2322 | if Nkind (Right_Str) = N_String_Literal then | |
b54ddf5a BD |
2323 | if Left_Len /= 0 then |
2324 | Store_String_Chars (Strval (Right_Str)); | |
2325 | Folded_Val := End_String; | |
2326 | end if; | |
996ae0b0 | 2327 | else |
82c80734 | 2328 | Store_String_Char (UI_To_CC (Char_Literal_Value (Right_Str))); |
b54ddf5a | 2329 | Folded_Val := End_String; |
996ae0b0 RK |
2330 | end if; |
2331 | ||
2332 | Set_Is_Static_Expression (N, Stat); | |
2333 | ||
354c3840 AC |
2334 | -- If left operand is the empty string, the result is the |
2335 | -- right operand, including its bounds if anomalous. | |
f91b40db | 2336 | |
354c3840 AC |
2337 | if Left_Len = 0 |
2338 | and then Is_Array_Type (Etype (Right)) | |
2339 | and then Etype (Right) /= Any_String | |
2340 | then | |
2341 | Set_Etype (N, Etype (Right)); | |
996ae0b0 | 2342 | end if; |
354c3840 AC |
2343 | |
2344 | Fold_Str (N, Folded_Val, Static => Stat); | |
996ae0b0 RK |
2345 | end; |
2346 | end Eval_Concatenation; | |
2347 | ||
9b16cb57 RD |
2348 | ---------------------- |
2349 | -- Eval_Entity_Name -- | |
2350 | ---------------------- | |
2351 | ||
2352 | -- This procedure is used for identifiers and expanded names other than | |
2353 | -- named numbers (see Eval_Named_Integer, Eval_Named_Real. These are | |
2354 | -- static if they denote a static constant (RM 4.9(6)) or if the name | |
2355 | -- denotes an enumeration literal (RM 4.9(22)). | |
2356 | ||
2357 | procedure Eval_Entity_Name (N : Node_Id) is | |
2358 | Def_Id : constant Entity_Id := Entity (N); | |
2359 | Val : Node_Id; | |
2360 | ||
2361 | begin | |
2362 | -- Enumeration literals are always considered to be constants | |
2363 | -- and cannot raise constraint error (RM 4.9(22)). | |
2364 | ||
2365 | if Ekind (Def_Id) = E_Enumeration_Literal then | |
2366 | Set_Is_Static_Expression (N); | |
2367 | return; | |
2368 | ||
2369 | -- A name is static if it denotes a static constant (RM 4.9(5)), and | |
2370 | -- we also copy Raise_Constraint_Error. Notice that even if non-static, | |
2371 | -- it does not violate 10.2.1(8) here, since this is not a variable. | |
2372 | ||
2373 | elsif Ekind (Def_Id) = E_Constant then | |
2374 | ||
e03f7ccf AC |
2375 | -- Deferred constants must always be treated as nonstatic outside the |
2376 | -- scope of their full view. | |
9b16cb57 RD |
2377 | |
2378 | if Present (Full_View (Def_Id)) | |
2379 | and then not In_Open_Scopes (Scope (Def_Id)) | |
2380 | then | |
2381 | Val := Empty; | |
2382 | else | |
2383 | Val := Constant_Value (Def_Id); | |
2384 | end if; | |
2385 | ||
2386 | if Present (Val) then | |
2387 | Set_Is_Static_Expression | |
2388 | (N, Is_Static_Expression (Val) | |
2389 | and then Is_Static_Subtype (Etype (Def_Id))); | |
2390 | Set_Raises_Constraint_Error (N, Raises_Constraint_Error (Val)); | |
2391 | ||
2392 | if not Is_Static_Expression (N) | |
2393 | and then not Is_Generic_Type (Etype (N)) | |
2394 | then | |
2395 | Validate_Static_Object_Name (N); | |
2396 | end if; | |
2397 | ||
e03f7ccf AC |
2398 | -- Mark constant condition in SCOs |
2399 | ||
2400 | if Generate_SCO | |
2401 | and then Comes_From_Source (N) | |
2402 | and then Is_Boolean_Type (Etype (Def_Id)) | |
2403 | and then Compile_Time_Known_Value (N) | |
2404 | then | |
2405 | Set_SCO_Condition (N, Expr_Value_E (N) = Standard_True); | |
2406 | end if; | |
2407 | ||
9b16cb57 RD |
2408 | return; |
2409 | end if; | |
2410 | end if; | |
2411 | ||
2412 | -- Fall through if the name is not static | |
2413 | ||
2414 | Validate_Static_Object_Name (N); | |
2415 | end Eval_Entity_Name; | |
2416 | ||
2417 | ------------------------ | |
2418 | -- Eval_If_Expression -- | |
2419 | ------------------------ | |
996ae0b0 | 2420 | |
9b16cb57 | 2421 | -- We can fold to a static expression if the condition and both dependent |
1cf3727f | 2422 | -- expressions are static. Otherwise, the only required processing is to do |
4d777a71 | 2423 | -- the check for non-static context for the then and else expressions. |
996ae0b0 | 2424 | |
9b16cb57 | 2425 | procedure Eval_If_Expression (N : Node_Id) is |
4d777a71 AC |
2426 | Condition : constant Node_Id := First (Expressions (N)); |
2427 | Then_Expr : constant Node_Id := Next (Condition); | |
2428 | Else_Expr : constant Node_Id := Next (Then_Expr); | |
2429 | Result : Node_Id; | |
2430 | Non_Result : Node_Id; | |
2431 | ||
2432 | Rstat : constant Boolean := | |
2433 | Is_Static_Expression (Condition) | |
2434 | and then | |
2435 | Is_Static_Expression (Then_Expr) | |
2436 | and then | |
2437 | Is_Static_Expression (Else_Expr); | |
edab6088 | 2438 | -- True if result is static |
4d777a71 | 2439 | |
996ae0b0 | 2440 | begin |
edab6088 RD |
2441 | -- If result not static, nothing to do, otherwise set static result |
2442 | ||
2443 | if not Rstat then | |
2444 | return; | |
2445 | else | |
2446 | Set_Is_Static_Expression (N); | |
2447 | end if; | |
2448 | ||
4d777a71 AC |
2449 | -- If any operand is Any_Type, just propagate to result and do not try |
2450 | -- to fold, this prevents cascaded errors. | |
2451 | ||
2452 | if Etype (Condition) = Any_Type or else | |
2453 | Etype (Then_Expr) = Any_Type or else | |
2454 | Etype (Else_Expr) = Any_Type | |
2455 | then | |
2456 | Set_Etype (N, Any_Type); | |
2457 | Set_Is_Static_Expression (N, False); | |
2458 | return; | |
edab6088 RD |
2459 | end if; |
2460 | ||
4bd4bb7f | 2461 | -- If condition raises constraint error then we have already signaled |
edab6088 RD |
2462 | -- an error, and we just propagate to the result and do not fold. |
2463 | ||
2464 | if Raises_Constraint_Error (Condition) then | |
2465 | Set_Raises_Constraint_Error (N); | |
2466 | return; | |
2467 | end if; | |
4d777a71 AC |
2468 | |
2469 | -- Static case where we can fold. Note that we don't try to fold cases | |
2470 | -- where the condition is known at compile time, but the result is | |
2471 | -- non-static. This avoids possible cases of infinite recursion where | |
2472 | -- the expander puts in a redundant test and we remove it. Instead we | |
2473 | -- deal with these cases in the expander. | |
2474 | ||
edab6088 | 2475 | -- Select result operand |
4d777a71 | 2476 | |
edab6088 RD |
2477 | if Is_True (Expr_Value (Condition)) then |
2478 | Result := Then_Expr; | |
2479 | Non_Result := Else_Expr; | |
2480 | else | |
2481 | Result := Else_Expr; | |
2482 | Non_Result := Then_Expr; | |
2483 | end if; | |
4d777a71 | 2484 | |
edab6088 RD |
2485 | -- Note that it does not matter if the non-result operand raises a |
2486 | -- Constraint_Error, but if the result raises constraint error then we | |
2487 | -- replace the node with a raise constraint error. This will properly | |
2488 | -- propagate Raises_Constraint_Error since this flag is set in Result. | |
4d777a71 | 2489 | |
edab6088 RD |
2490 | if Raises_Constraint_Error (Result) then |
2491 | Rewrite_In_Raise_CE (N, Result); | |
2492 | Check_Non_Static_Context (Non_Result); | |
4d777a71 | 2493 | |
edab6088 | 2494 | -- Otherwise the result operand replaces the original node |
4d777a71 AC |
2495 | |
2496 | else | |
edab6088 RD |
2497 | Rewrite (N, Relocate_Node (Result)); |
2498 | Set_Is_Static_Expression (N); | |
4d777a71 | 2499 | end if; |
9b16cb57 | 2500 | end Eval_If_Expression; |
996ae0b0 RK |
2501 | |
2502 | ---------------------------- | |
2503 | -- Eval_Indexed_Component -- | |
2504 | ---------------------------- | |
2505 | ||
8cbb664e MG |
2506 | -- Indexed components are never static, so we need to perform the check |
2507 | -- for non-static context on the index values. Then, we check if the | |
2508 | -- value can be obtained at compile time, even though it is non-static. | |
996ae0b0 RK |
2509 | |
2510 | procedure Eval_Indexed_Component (N : Node_Id) is | |
2511 | Expr : Node_Id; | |
2512 | ||
2513 | begin | |
fbf5a39b AC |
2514 | -- Check for non-static context on index values |
2515 | ||
996ae0b0 RK |
2516 | Expr := First (Expressions (N)); |
2517 | while Present (Expr) loop | |
2518 | Check_Non_Static_Context (Expr); | |
2519 | Next (Expr); | |
2520 | end loop; | |
2521 | ||
fbf5a39b AC |
2522 | -- If the indexed component appears in an object renaming declaration |
2523 | -- then we do not want to try to evaluate it, since in this case we | |
2524 | -- need the identity of the array element. | |
2525 | ||
2526 | if Nkind (Parent (N)) = N_Object_Renaming_Declaration then | |
2527 | return; | |
2528 | ||
2529 | -- Similarly if the indexed component appears as the prefix of an | |
2530 | -- attribute we don't want to evaluate it, because at least for | |
2531 | -- some cases of attributes we need the identify (e.g. Access, Size) | |
2532 | ||
2533 | elsif Nkind (Parent (N)) = N_Attribute_Reference then | |
2534 | return; | |
2535 | end if; | |
2536 | ||
2537 | -- Note: there are other cases, such as the left side of an assignment, | |
2538 | -- or an OUT parameter for a call, where the replacement results in the | |
2539 | -- illegal use of a constant, But these cases are illegal in the first | |
2540 | -- place, so the replacement, though silly, is harmless. | |
2541 | ||
2542 | -- Now see if this is a constant array reference | |
8cbb664e MG |
2543 | |
2544 | if List_Length (Expressions (N)) = 1 | |
2545 | and then Is_Entity_Name (Prefix (N)) | |
2546 | and then Ekind (Entity (Prefix (N))) = E_Constant | |
2547 | and then Present (Constant_Value (Entity (Prefix (N)))) | |
2548 | then | |
2549 | declare | |
2550 | Loc : constant Source_Ptr := Sloc (N); | |
2551 | Arr : constant Node_Id := Constant_Value (Entity (Prefix (N))); | |
2552 | Sub : constant Node_Id := First (Expressions (N)); | |
2553 | ||
2554 | Atyp : Entity_Id; | |
2555 | -- Type of array | |
2556 | ||
2557 | Lin : Nat; | |
2558 | -- Linear one's origin subscript value for array reference | |
2559 | ||
2560 | Lbd : Node_Id; | |
2561 | -- Lower bound of the first array index | |
2562 | ||
2563 | Elm : Node_Id; | |
2564 | -- Value from constant array | |
2565 | ||
2566 | begin | |
2567 | Atyp := Etype (Arr); | |
2568 | ||
2569 | if Is_Access_Type (Atyp) then | |
2570 | Atyp := Designated_Type (Atyp); | |
2571 | end if; | |
2572 | ||
9dbf1c3e RD |
2573 | -- If we have an array type (we should have but perhaps there are |
2574 | -- error cases where this is not the case), then see if we can do | |
2575 | -- a constant evaluation of the array reference. | |
8cbb664e | 2576 | |
ebd34478 | 2577 | if Is_Array_Type (Atyp) and then Atyp /= Any_Composite then |
8cbb664e MG |
2578 | if Ekind (Atyp) = E_String_Literal_Subtype then |
2579 | Lbd := String_Literal_Low_Bound (Atyp); | |
2580 | else | |
2581 | Lbd := Type_Low_Bound (Etype (First_Index (Atyp))); | |
2582 | end if; | |
2583 | ||
2584 | if Compile_Time_Known_Value (Sub) | |
2585 | and then Nkind (Arr) = N_Aggregate | |
2586 | and then Compile_Time_Known_Value (Lbd) | |
2587 | and then Is_Discrete_Type (Component_Type (Atyp)) | |
2588 | then | |
2589 | Lin := UI_To_Int (Expr_Value (Sub) - Expr_Value (Lbd)) + 1; | |
2590 | ||
2591 | if List_Length (Expressions (Arr)) >= Lin then | |
2592 | Elm := Pick (Expressions (Arr), Lin); | |
2593 | ||
2594 | -- If the resulting expression is compile time known, | |
2595 | -- then we can rewrite the indexed component with this | |
2596 | -- value, being sure to mark the result as non-static. | |
2597 | -- We also reset the Sloc, in case this generates an | |
2598 | -- error later on (e.g. 136'Access). | |
2599 | ||
2600 | if Compile_Time_Known_Value (Elm) then | |
2601 | Rewrite (N, Duplicate_Subexpr_No_Checks (Elm)); | |
2602 | Set_Is_Static_Expression (N, False); | |
2603 | Set_Sloc (N, Loc); | |
2604 | end if; | |
2605 | end if; | |
9fbb3ae6 AC |
2606 | |
2607 | -- We can also constant-fold if the prefix is a string literal. | |
2608 | -- This will be useful in an instantiation or an inlining. | |
2609 | ||
2610 | elsif Compile_Time_Known_Value (Sub) | |
2611 | and then Nkind (Arr) = N_String_Literal | |
2612 | and then Compile_Time_Known_Value (Lbd) | |
2613 | and then Expr_Value (Lbd) = 1 | |
2614 | and then Expr_Value (Sub) <= | |
2615 | String_Literal_Length (Etype (Arr)) | |
2616 | then | |
2617 | declare | |
2618 | C : constant Char_Code := | |
2619 | Get_String_Char (Strval (Arr), | |
2620 | UI_To_Int (Expr_Value (Sub))); | |
2621 | begin | |
2622 | Set_Character_Literal_Name (C); | |
2623 | ||
2624 | Elm := | |
2625 | Make_Character_Literal (Loc, | |
2626 | Chars => Name_Find, | |
2627 | Char_Literal_Value => UI_From_CC (C)); | |
2628 | Set_Etype (Elm, Component_Type (Atyp)); | |
2629 | Rewrite (N, Duplicate_Subexpr_No_Checks (Elm)); | |
2630 | Set_Is_Static_Expression (N, False); | |
2631 | end; | |
8cbb664e MG |
2632 | end if; |
2633 | end if; | |
2634 | end; | |
2635 | end if; | |
996ae0b0 RK |
2636 | end Eval_Indexed_Component; |
2637 | ||
2638 | -------------------------- | |
2639 | -- Eval_Integer_Literal -- | |
2640 | -------------------------- | |
2641 | ||
2642 | -- Numeric literals are static (RM 4.9(1)), and have already been marked | |
2643 | -- as static by the analyzer. The reason we did it that early is to allow | |
2644 | -- the possibility of turning off the Is_Static_Expression flag after | |
9dbf1c3e RD |
2645 | -- analysis, but before resolution, when integer literals are generated in |
2646 | -- the expander that do not correspond to static expressions. | |
996ae0b0 RK |
2647 | |
2648 | procedure Eval_Integer_Literal (N : Node_Id) is | |
2649 | T : constant Entity_Id := Etype (N); | |
2650 | ||
5d09245e | 2651 | function In_Any_Integer_Context return Boolean; |
1d1bd8ad AC |
2652 | -- If the literal is resolved with a specific type in a context where |
2653 | -- the expected type is Any_Integer, there are no range checks on the | |
2654 | -- literal. By the time the literal is evaluated, it carries the type | |
2655 | -- imposed by the enclosing expression, and we must recover the context | |
2656 | -- to determine that Any_Integer is meant. | |
5d09245e AC |
2657 | |
2658 | ---------------------------- | |
09494c32 | 2659 | -- In_Any_Integer_Context -- |
5d09245e AC |
2660 | ---------------------------- |
2661 | ||
2662 | function In_Any_Integer_Context return Boolean is | |
2663 | Par : constant Node_Id := Parent (N); | |
2664 | K : constant Node_Kind := Nkind (Par); | |
2665 | ||
2666 | begin | |
2667 | -- Any_Integer also appears in digits specifications for real types, | |
1d1bd8ad AC |
2668 | -- but those have bounds smaller that those of any integer base type, |
2669 | -- so we can safely ignore these cases. | |
5d09245e | 2670 | |
80298c3b AC |
2671 | return Nkind_In (K, N_Number_Declaration, |
2672 | N_Attribute_Reference, | |
2673 | N_Attribute_Definition_Clause, | |
2674 | N_Modular_Type_Definition, | |
2675 | N_Signed_Integer_Type_Definition); | |
5d09245e AC |
2676 | end In_Any_Integer_Context; |
2677 | ||
2678 | -- Start of processing for Eval_Integer_Literal | |
2679 | ||
996ae0b0 | 2680 | begin |
5d09245e | 2681 | |
996ae0b0 | 2682 | -- If the literal appears in a non-expression context, then it is |
1d1bd8ad AC |
2683 | -- certainly appearing in a non-static context, so check it. This is |
2684 | -- actually a redundant check, since Check_Non_Static_Context would | |
42f9f0fc | 2685 | -- check it, but it seems worthwhile to optimize out the call. |
996ae0b0 | 2686 | |
a51368fa AC |
2687 | -- An exception is made for a literal in an if or case expression |
2688 | ||
2689 | if (Nkind_In (Parent (N), N_If_Expression, N_Case_Expression_Alternative) | |
2690 | or else Nkind (Parent (N)) not in N_Subexpr) | |
5d09245e AC |
2691 | and then not In_Any_Integer_Context |
2692 | then | |
996ae0b0 RK |
2693 | Check_Non_Static_Context (N); |
2694 | end if; | |
2695 | ||
2696 | -- Modular integer literals must be in their base range | |
2697 | ||
2698 | if Is_Modular_Integer_Type (T) | |
c800f862 | 2699 | and then Is_Out_Of_Range (N, Base_Type (T), Assume_Valid => True) |
996ae0b0 RK |
2700 | then |
2701 | Out_Of_Range (N); | |
2702 | end if; | |
2703 | end Eval_Integer_Literal; | |
2704 | ||
2705 | --------------------- | |
2706 | -- Eval_Logical_Op -- | |
2707 | --------------------- | |
2708 | ||
2709 | -- Logical operations are static functions, so the result is potentially | |
2710 | -- static if both operands are potentially static (RM 4.9(7), 4.9(20)). | |
2711 | ||
2712 | procedure Eval_Logical_Op (N : Node_Id) is | |
2713 | Left : constant Node_Id := Left_Opnd (N); | |
2714 | Right : constant Node_Id := Right_Opnd (N); | |
2715 | Stat : Boolean; | |
2716 | Fold : Boolean; | |
2717 | ||
2718 | begin | |
2719 | -- If not foldable we are done | |
2720 | ||
2721 | Test_Expression_Is_Foldable (N, Left, Right, Stat, Fold); | |
2722 | ||
2723 | if not Fold then | |
2724 | return; | |
2725 | end if; | |
2726 | ||
2727 | -- Compile time evaluation of logical operation | |
2728 | ||
2729 | declare | |
2730 | Left_Int : constant Uint := Expr_Value (Left); | |
2731 | Right_Int : constant Uint := Expr_Value (Right); | |
2732 | ||
2733 | begin | |
7a5b62b0 | 2734 | if Is_Modular_Integer_Type (Etype (N)) then |
996ae0b0 RK |
2735 | declare |
2736 | Left_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1); | |
2737 | Right_Bits : Bits (0 .. UI_To_Int (Esize (Etype (N))) - 1); | |
2738 | ||
2739 | begin | |
2740 | To_Bits (Left_Int, Left_Bits); | |
2741 | To_Bits (Right_Int, Right_Bits); | |
2742 | ||
2743 | -- Note: should really be able to use array ops instead of | |
2744 | -- these loops, but they weren't working at the time ??? | |
2745 | ||
2746 | if Nkind (N) = N_Op_And then | |
2747 | for J in Left_Bits'Range loop | |
2748 | Left_Bits (J) := Left_Bits (J) and Right_Bits (J); | |
2749 | end loop; | |
2750 | ||
2751 | elsif Nkind (N) = N_Op_Or then | |
2752 | for J in Left_Bits'Range loop | |
2753 | Left_Bits (J) := Left_Bits (J) or Right_Bits (J); | |
2754 | end loop; | |
2755 | ||
2756 | else | |
2757 | pragma Assert (Nkind (N) = N_Op_Xor); | |
2758 | ||
2759 | for J in Left_Bits'Range loop | |
2760 | Left_Bits (J) := Left_Bits (J) xor Right_Bits (J); | |
2761 | end loop; | |
2762 | end if; | |
2763 | ||
fbf5a39b | 2764 | Fold_Uint (N, From_Bits (Left_Bits, Etype (N)), Stat); |
996ae0b0 RK |
2765 | end; |
2766 | ||
2767 | else | |
2768 | pragma Assert (Is_Boolean_Type (Etype (N))); | |
2769 | ||
2770 | if Nkind (N) = N_Op_And then | |
2771 | Fold_Uint (N, | |
fbf5a39b | 2772 | Test (Is_True (Left_Int) and then Is_True (Right_Int)), Stat); |
996ae0b0 RK |
2773 | |
2774 | elsif Nkind (N) = N_Op_Or then | |
2775 | Fold_Uint (N, | |
fbf5a39b | 2776 | Test (Is_True (Left_Int) or else Is_True (Right_Int)), Stat); |
996ae0b0 RK |
2777 | |
2778 | else | |
2779 | pragma Assert (Nkind (N) = N_Op_Xor); | |
2780 | Fold_Uint (N, | |
fbf5a39b | 2781 | Test (Is_True (Left_Int) xor Is_True (Right_Int)), Stat); |
996ae0b0 RK |
2782 | end if; |
2783 | end if; | |
996ae0b0 RK |
2784 | end; |
2785 | end Eval_Logical_Op; | |
2786 | ||
2787 | ------------------------ | |
2788 | -- Eval_Membership_Op -- | |
2789 | ------------------------ | |
2790 | ||
1d1bd8ad AC |
2791 | -- A membership test is potentially static if the expression is static, and |
2792 | -- the range is a potentially static range, or is a subtype mark denoting a | |
2793 | -- static subtype (RM 4.9(12)). | |
996ae0b0 RK |
2794 | |
2795 | procedure Eval_Membership_Op (N : Node_Id) is | |
edab6088 | 2796 | Alts : constant List_Id := Alternatives (N); |
87feba05 AC |
2797 | Choice : constant Node_Id := Right_Opnd (N); |
2798 | Expr : constant Node_Id := Left_Opnd (N); | |
edab6088 | 2799 | Result : Match_Result; |
996ae0b0 RK |
2800 | |
2801 | begin | |
1d1bd8ad AC |
2802 | -- Ignore if error in either operand, except to make sure that Any_Type |
2803 | -- is properly propagated to avoid junk cascaded errors. | |
996ae0b0 | 2804 | |
87feba05 AC |
2805 | if Etype (Expr) = Any_Type |
2806 | or else (Present (Choice) and then Etype (Choice) = Any_Type) | |
edab6088 | 2807 | then |
996ae0b0 RK |
2808 | Set_Etype (N, Any_Type); |
2809 | return; | |
2810 | end if; | |
2811 | ||
edab6088 | 2812 | -- If left operand non-static, then nothing to do |
996ae0b0 | 2813 | |
87feba05 | 2814 | if not Is_Static_Expression (Expr) then |
edab6088 RD |
2815 | return; |
2816 | end if; | |
996ae0b0 | 2817 | |
edab6088 | 2818 | -- If choice is non-static, left operand is in non-static context |
996ae0b0 | 2819 | |
87feba05 | 2820 | if (Present (Choice) and then not Is_Static_Choice (Choice)) |
edab6088 RD |
2821 | or else (Present (Alts) and then not Is_Static_Choice_List (Alts)) |
2822 | then | |
87feba05 | 2823 | Check_Non_Static_Context (Expr); |
edab6088 RD |
2824 | return; |
2825 | end if; | |
996ae0b0 | 2826 | |
edab6088 | 2827 | -- Otherwise we definitely have a static expression |
996ae0b0 | 2828 | |
edab6088 | 2829 | Set_Is_Static_Expression (N); |
996ae0b0 | 2830 | |
edab6088 | 2831 | -- If left operand raises constraint error, propagate and we are done |
996ae0b0 | 2832 | |
87feba05 | 2833 | if Raises_Constraint_Error (Expr) then |
edab6088 | 2834 | Set_Raises_Constraint_Error (N, True); |
996ae0b0 | 2835 | |
edab6088 | 2836 | -- See if we match |
996ae0b0 | 2837 | |
edab6088 | 2838 | else |
87feba05 AC |
2839 | if Present (Choice) then |
2840 | Result := Choice_Matches (Expr, Choice); | |
996ae0b0 | 2841 | else |
87feba05 | 2842 | Result := Choices_Match (Expr, Alts); |
996ae0b0 RK |
2843 | end if; |
2844 | ||
edab6088 RD |
2845 | -- If result is Non_Static, it means that we raise Constraint_Error, |
2846 | -- since we already tested that the operands were themselves static. | |
996ae0b0 | 2847 | |
edab6088 RD |
2848 | if Result = Non_Static then |
2849 | Set_Raises_Constraint_Error (N); | |
996ae0b0 | 2850 | |
edab6088 | 2851 | -- Otherwise we have our result (flipped if NOT IN case) |
996ae0b0 RK |
2852 | |
2853 | else | |
edab6088 RD |
2854 | Fold_Uint |
2855 | (N, Test ((Result = Match) xor (Nkind (N) = N_Not_In)), True); | |
2856 | Warn_On_Known_Condition (N); | |
996ae0b0 | 2857 | end if; |
996ae0b0 | 2858 | end if; |
996ae0b0 RK |
2859 | end Eval_Membership_Op; |
2860 | ||
2861 | ------------------------ | |
2862 | -- Eval_Named_Integer -- | |
2863 | ------------------------ | |
2864 | ||
2865 | procedure Eval_Named_Integer (N : Node_Id) is | |
2866 | begin | |
2867 | Fold_Uint (N, | |
fbf5a39b | 2868 | Expr_Value (Expression (Declaration_Node (Entity (N)))), True); |
996ae0b0 RK |
2869 | end Eval_Named_Integer; |
2870 | ||
2871 | --------------------- | |
2872 | -- Eval_Named_Real -- | |
2873 | --------------------- | |
2874 | ||
2875 | procedure Eval_Named_Real (N : Node_Id) is | |
2876 | begin | |
2877 | Fold_Ureal (N, | |
fbf5a39b | 2878 | Expr_Value_R (Expression (Declaration_Node (Entity (N)))), True); |
996ae0b0 RK |
2879 | end Eval_Named_Real; |
2880 | ||
2881 | ------------------- | |
2882 | -- Eval_Op_Expon -- | |
2883 | ------------------- | |
2884 | ||
2885 | -- Exponentiation is a static functions, so the result is potentially | |
2886 | -- static if both operands are potentially static (RM 4.9(7), 4.9(20)). | |
2887 | ||
2888 | procedure Eval_Op_Expon (N : Node_Id) is | |
2889 | Left : constant Node_Id := Left_Opnd (N); | |
2890 | Right : constant Node_Id := Right_Opnd (N); | |
2891 | Stat : Boolean; | |
2892 | Fold : Boolean; | |
2893 | ||
2894 | begin | |
2895 | -- If not foldable we are done | |
2896 | ||
6c3c671e AC |
2897 | Test_Expression_Is_Foldable |
2898 | (N, Left, Right, Stat, Fold, CRT_Safe => True); | |
2899 | ||
2900 | -- Return if not foldable | |
996ae0b0 RK |
2901 | |
2902 | if not Fold then | |
2903 | return; | |
2904 | end if; | |
2905 | ||
6c3c671e AC |
2906 | if Configurable_Run_Time_Mode and not Stat then |
2907 | return; | |
2908 | end if; | |
2909 | ||
996ae0b0 RK |
2910 | -- Fold exponentiation operation |
2911 | ||
2912 | declare | |
2913 | Right_Int : constant Uint := Expr_Value (Right); | |
2914 | ||
2915 | begin | |
2916 | -- Integer case | |
2917 | ||
2918 | if Is_Integer_Type (Etype (Left)) then | |
2919 | declare | |
2920 | Left_Int : constant Uint := Expr_Value (Left); | |
2921 | Result : Uint; | |
2922 | ||
2923 | begin | |
22cb89b5 AC |
2924 | -- Exponentiation of an integer raises Constraint_Error for a |
2925 | -- negative exponent (RM 4.5.6). | |
996ae0b0 RK |
2926 | |
2927 | if Right_Int < 0 then | |
2928 | Apply_Compile_Time_Constraint_Error | |
80298c3b | 2929 | (N, "integer exponent negative", CE_Range_Check_Failed, |
fbf5a39b | 2930 | Warn => not Stat); |
996ae0b0 RK |
2931 | return; |
2932 | ||
2933 | else | |
2934 | if OK_Bits (N, Num_Bits (Left_Int) * Right_Int) then | |
2935 | Result := Left_Int ** Right_Int; | |
2936 | else | |
2937 | Result := Left_Int; | |
2938 | end if; | |
2939 | ||
2940 | if Is_Modular_Integer_Type (Etype (N)) then | |
2941 | Result := Result mod Modulus (Etype (N)); | |
2942 | end if; | |
2943 | ||
fbf5a39b | 2944 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
2945 | end if; |
2946 | end; | |
2947 | ||
2948 | -- Real case | |
2949 | ||
2950 | else | |
2951 | declare | |
2952 | Left_Real : constant Ureal := Expr_Value_R (Left); | |
2953 | ||
2954 | begin | |
2955 | -- Cannot have a zero base with a negative exponent | |
2956 | ||
2957 | if UR_Is_Zero (Left_Real) then | |
2958 | ||
2959 | if Right_Int < 0 then | |
2960 | Apply_Compile_Time_Constraint_Error | |
80298c3b | 2961 | (N, "zero ** negative integer", CE_Range_Check_Failed, |
fbf5a39b | 2962 | Warn => not Stat); |
996ae0b0 RK |
2963 | return; |
2964 | else | |
fbf5a39b | 2965 | Fold_Ureal (N, Ureal_0, Stat); |
996ae0b0 RK |
2966 | end if; |
2967 | ||
2968 | else | |
fbf5a39b | 2969 | Fold_Ureal (N, Left_Real ** Right_Int, Stat); |
996ae0b0 RK |
2970 | end if; |
2971 | end; | |
2972 | end if; | |
996ae0b0 RK |
2973 | end; |
2974 | end Eval_Op_Expon; | |
2975 | ||
2976 | ----------------- | |
2977 | -- Eval_Op_Not -- | |
2978 | ----------------- | |
2979 | ||
21d7ef70 | 2980 | -- The not operation is a static functions, so the result is potentially |
996ae0b0 RK |
2981 | -- static if the operand is potentially static (RM 4.9(7), 4.9(20)). |
2982 | ||
2983 | procedure Eval_Op_Not (N : Node_Id) is | |
2984 | Right : constant Node_Id := Right_Opnd (N); | |
2985 | Stat : Boolean; | |
2986 | Fold : Boolean; | |
2987 | ||
2988 | begin | |
2989 | -- If not foldable we are done | |
2990 | ||
2991 | Test_Expression_Is_Foldable (N, Right, Stat, Fold); | |
2992 | ||
2993 | if not Fold then | |
2994 | return; | |
2995 | end if; | |
2996 | ||
2997 | -- Fold not operation | |
2998 | ||
2999 | declare | |
3000 | Rint : constant Uint := Expr_Value (Right); | |
3001 | Typ : constant Entity_Id := Etype (N); | |
3002 | ||
3003 | begin | |
1d1bd8ad AC |
3004 | -- Negation is equivalent to subtracting from the modulus minus one. |
3005 | -- For a binary modulus this is equivalent to the ones-complement of | |
a95f708e | 3006 | -- the original value. For a nonbinary modulus this is an arbitrary |
1d1bd8ad | 3007 | -- but consistent definition. |
996ae0b0 RK |
3008 | |
3009 | if Is_Modular_Integer_Type (Typ) then | |
fbf5a39b | 3010 | Fold_Uint (N, Modulus (Typ) - 1 - Rint, Stat); |
80298c3b | 3011 | else pragma Assert (Is_Boolean_Type (Typ)); |
fbf5a39b | 3012 | Fold_Uint (N, Test (not Is_True (Rint)), Stat); |
996ae0b0 RK |
3013 | end if; |
3014 | ||
3015 | Set_Is_Static_Expression (N, Stat); | |
3016 | end; | |
3017 | end Eval_Op_Not; | |
3018 | ||
3019 | ------------------------------- | |
3020 | -- Eval_Qualified_Expression -- | |
3021 | ------------------------------- | |
3022 | ||
3023 | -- A qualified expression is potentially static if its subtype mark denotes | |
3024 | -- a static subtype and its expression is potentially static (RM 4.9 (11)). | |
3025 | ||
3026 | procedure Eval_Qualified_Expression (N : Node_Id) is | |
3027 | Operand : constant Node_Id := Expression (N); | |
3028 | Target_Type : constant Entity_Id := Entity (Subtype_Mark (N)); | |
3029 | ||
07fc65c4 GB |
3030 | Stat : Boolean; |
3031 | Fold : Boolean; | |
3032 | Hex : Boolean; | |
996ae0b0 RK |
3033 | |
3034 | begin | |
1d1bd8ad | 3035 | -- Can only fold if target is string or scalar and subtype is static. |
22cb89b5 AC |
3036 | -- Also, do not fold if our parent is an allocator (this is because the |
3037 | -- qualified expression is really part of the syntactic structure of an | |
3038 | -- allocator, and we do not want to end up with something that | |
996ae0b0 RK |
3039 | -- corresponds to "new 1" where the 1 is the result of folding a |
3040 | -- qualified expression). | |
3041 | ||
3042 | if not Is_Static_Subtype (Target_Type) | |
3043 | or else Nkind (Parent (N)) = N_Allocator | |
3044 | then | |
3045 | Check_Non_Static_Context (Operand); | |
af152989 | 3046 | |
1d1bd8ad AC |
3047 | -- If operand is known to raise constraint_error, set the flag on the |
3048 | -- expression so it does not get optimized away. | |
af152989 AC |
3049 | |
3050 | if Nkind (Operand) = N_Raise_Constraint_Error then | |
3051 | Set_Raises_Constraint_Error (N); | |
3052 | end if; | |
7324bf49 | 3053 | |
996ae0b0 RK |
3054 | return; |
3055 | end if; | |
3056 | ||
3057 | -- If not foldable we are done | |
3058 | ||
3059 | Test_Expression_Is_Foldable (N, Operand, Stat, Fold); | |
3060 | ||
3061 | if not Fold then | |
3062 | return; | |
3063 | ||
3064 | -- Don't try fold if target type has constraint error bounds | |
3065 | ||
3066 | elsif not Is_OK_Static_Subtype (Target_Type) then | |
3067 | Set_Raises_Constraint_Error (N); | |
3068 | return; | |
3069 | end if; | |
3070 | ||
07fc65c4 GB |
3071 | -- Here we will fold, save Print_In_Hex indication |
3072 | ||
3073 | Hex := Nkind (Operand) = N_Integer_Literal | |
3074 | and then Print_In_Hex (Operand); | |
3075 | ||
996ae0b0 RK |
3076 | -- Fold the result of qualification |
3077 | ||
3078 | if Is_Discrete_Type (Target_Type) then | |
fbf5a39b | 3079 | Fold_Uint (N, Expr_Value (Operand), Stat); |
996ae0b0 | 3080 | |
07fc65c4 GB |
3081 | -- Preserve Print_In_Hex indication |
3082 | ||
3083 | if Hex and then Nkind (N) = N_Integer_Literal then | |
3084 | Set_Print_In_Hex (N); | |
3085 | end if; | |
3086 | ||
996ae0b0 | 3087 | elsif Is_Real_Type (Target_Type) then |
fbf5a39b | 3088 | Fold_Ureal (N, Expr_Value_R (Operand), Stat); |
996ae0b0 RK |
3089 | |
3090 | else | |
fbf5a39b | 3091 | Fold_Str (N, Strval (Get_String_Val (Operand)), Stat); |
996ae0b0 RK |
3092 | |
3093 | if not Stat then | |
3094 | Set_Is_Static_Expression (N, False); | |
3095 | else | |
3096 | Check_String_Literal_Length (N, Target_Type); | |
3097 | end if; | |
3098 | ||
3099 | return; | |
3100 | end if; | |
3101 | ||
fbf5a39b AC |
3102 | -- The expression may be foldable but not static |
3103 | ||
3104 | Set_Is_Static_Expression (N, Stat); | |
3105 | ||
c800f862 | 3106 | if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then |
996ae0b0 RK |
3107 | Out_Of_Range (N); |
3108 | end if; | |
996ae0b0 RK |
3109 | end Eval_Qualified_Expression; |
3110 | ||
3111 | ----------------------- | |
3112 | -- Eval_Real_Literal -- | |
3113 | ----------------------- | |
3114 | ||
3115 | -- Numeric literals are static (RM 4.9(1)), and have already been marked | |
3116 | -- as static by the analyzer. The reason we did it that early is to allow | |
3117 | -- the possibility of turning off the Is_Static_Expression flag after | |
3118 | -- analysis, but before resolution, when integer literals are generated | |
3119 | -- in the expander that do not correspond to static expressions. | |
3120 | ||
3121 | procedure Eval_Real_Literal (N : Node_Id) is | |
a1980be8 GB |
3122 | PK : constant Node_Kind := Nkind (Parent (N)); |
3123 | ||
996ae0b0 | 3124 | begin |
1d1bd8ad AC |
3125 | -- If the literal appears in a non-expression context and not as part of |
3126 | -- a number declaration, then it is appearing in a non-static context, | |
3127 | -- so check it. | |
996ae0b0 | 3128 | |
a1980be8 | 3129 | if PK not in N_Subexpr and then PK /= N_Number_Declaration then |
996ae0b0 RK |
3130 | Check_Non_Static_Context (N); |
3131 | end if; | |
996ae0b0 RK |
3132 | end Eval_Real_Literal; |
3133 | ||
3134 | ------------------------ | |
3135 | -- Eval_Relational_Op -- | |
3136 | ------------------------ | |
3137 | ||
8a95f4e8 RD |
3138 | -- Relational operations are static functions, so the result is static if |
3139 | -- both operands are static (RM 4.9(7), 4.9(20)), except that for strings, | |
3140 | -- the result is never static, even if the operands are. | |
996ae0b0 | 3141 | |
fc3a3f3b RD |
3142 | -- However, for internally generated nodes, we allow string equality and |
3143 | -- inequality to be static. This is because we rewrite A in "ABC" as an | |
3144 | -- equality test A = "ABC", and the former is definitely static. | |
3145 | ||
996ae0b0 | 3146 | procedure Eval_Relational_Op (N : Node_Id) is |
634a926b AC |
3147 | Left : constant Node_Id := Left_Opnd (N); |
3148 | Right : constant Node_Id := Right_Opnd (N); | |
996ae0b0 | 3149 | |
634a926b AC |
3150 | procedure Decompose_Expr |
3151 | (Expr : Node_Id; | |
3152 | Ent : out Entity_Id; | |
3153 | Kind : out Character; | |
3154 | Cons : out Uint; | |
3155 | Orig : Boolean := True); | |
3156 | -- Given expression Expr, see if it is of the form X [+/- K]. If so, Ent | |
3157 | -- is set to the entity in X, Kind is 'F','L','E' for 'First or 'Last or | |
3158 | -- simple entity, and Cons is the value of K. If the expression is not | |
3159 | -- of the required form, Ent is set to Empty. | |
3160 | -- | |
3161 | -- Orig indicates whether Expr is the original expression to consider, | |
3162 | -- or if we are handling a sub-expression (e.g. recursive call to | |
3163 | -- Decompose_Expr). | |
3164 | ||
3165 | procedure Fold_General_Op (Is_Static : Boolean); | |
3166 | -- Attempt to fold arbitrary relational operator N. Flag Is_Static must | |
3167 | -- be set when the operator denotes a static expression. | |
3168 | ||
3169 | procedure Fold_Static_Real_Op; | |
3170 | -- Attempt to fold static real type relational operator N | |
3171 | ||
3172 | function Static_Length (Expr : Node_Id) return Uint; | |
3173 | -- If Expr is an expression for a constrained array whose length is | |
3174 | -- known at compile time, return the non-negative length, otherwise | |
3175 | -- return -1. | |
3176 | ||
3177 | -------------------- | |
3178 | -- Decompose_Expr -- | |
3179 | -------------------- | |
3180 | ||
3181 | procedure Decompose_Expr | |
3182 | (Expr : Node_Id; | |
3183 | Ent : out Entity_Id; | |
3184 | Kind : out Character; | |
3185 | Cons : out Uint; | |
3186 | Orig : Boolean := True) | |
3187 | is | |
3188 | Exp : Node_Id; | |
996ae0b0 | 3189 | |
634a926b AC |
3190 | begin |
3191 | -- Assume that the expression does not meet the expected form | |
3192 | ||
3193 | Cons := No_Uint; | |
3194 | Ent := Empty; | |
3195 | Kind := '?'; | |
3196 | ||
3197 | if Nkind (Expr) = N_Op_Add | |
3198 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
996ae0b0 | 3199 | then |
634a926b AC |
3200 | Exp := Left_Opnd (Expr); |
3201 | Cons := Expr_Value (Right_Opnd (Expr)); | |
3202 | ||
3203 | elsif Nkind (Expr) = N_Op_Subtract | |
3204 | and then Compile_Time_Known_Value (Right_Opnd (Expr)) | |
3205 | then | |
3206 | Exp := Left_Opnd (Expr); | |
3207 | Cons := -Expr_Value (Right_Opnd (Expr)); | |
3208 | ||
3209 | -- If the bound is a constant created to remove side effects, recover | |
3210 | -- the original expression to see if it has one of the recognizable | |
3211 | -- forms. | |
3212 | ||
3213 | elsif Nkind (Expr) = N_Identifier | |
3214 | and then not Comes_From_Source (Entity (Expr)) | |
3215 | and then Ekind (Entity (Expr)) = E_Constant | |
3216 | and then Nkind (Parent (Entity (Expr))) = N_Object_Declaration | |
3217 | then | |
3218 | Exp := Expression (Parent (Entity (Expr))); | |
3219 | Decompose_Expr (Exp, Ent, Kind, Cons, Orig => False); | |
3220 | ||
3221 | -- If original expression includes an entity, create a reference | |
3222 | -- to it for use below. | |
3223 | ||
3224 | if Present (Ent) then | |
3225 | Exp := New_Occurrence_Of (Ent, Sloc (Ent)); | |
3226 | else | |
3227 | return; | |
3228 | end if; | |
3229 | ||
3230 | else | |
3231 | -- Only consider the case of X + 0 for a full expression, and | |
3232 | -- not when recursing, otherwise we may end up with evaluating | |
3233 | -- expressions not known at compile time to 0. | |
3234 | ||
3235 | if Orig then | |
3236 | Exp := Expr; | |
3237 | Cons := Uint_0; | |
3238 | else | |
3239 | return; | |
3240 | end if; | |
996ae0b0 RK |
3241 | end if; |
3242 | ||
634a926b | 3243 | -- At this stage Exp is set to the potential X |
45fc7ddb | 3244 | |
634a926b AC |
3245 | if Nkind (Exp) = N_Attribute_Reference then |
3246 | if Attribute_Name (Exp) = Name_First then | |
3247 | Kind := 'F'; | |
3248 | elsif Attribute_Name (Exp) = Name_Last then | |
3249 | Kind := 'L'; | |
3250 | else | |
3251 | return; | |
3252 | end if; | |
996ae0b0 | 3253 | |
634a926b | 3254 | Exp := Prefix (Exp); |
fbf5a39b | 3255 | |
634a926b AC |
3256 | else |
3257 | Kind := 'E'; | |
3258 | end if; | |
996ae0b0 | 3259 | |
634a926b AC |
3260 | if Is_Entity_Name (Exp) and then Present (Entity (Exp)) then |
3261 | Ent := Entity (Exp); | |
3262 | end if; | |
3263 | end Decompose_Expr; | |
3264 | ||
3265 | --------------------- | |
3266 | -- Fold_General_Op -- | |
3267 | --------------------- | |
3268 | ||
3269 | procedure Fold_General_Op (Is_Static : Boolean) is | |
3270 | CR : constant Compare_Result := | |
3271 | Compile_Time_Compare (Left, Right, Assume_Valid => False); | |
45fc7ddb | 3272 | |
634a926b AC |
3273 | Result : Boolean; |
3274 | ||
3275 | begin | |
3276 | if CR = Unknown then | |
3277 | return; | |
3278 | end if; | |
3279 | ||
3280 | case Nkind (N) is | |
3281 | when N_Op_Eq => | |
3282 | if CR = EQ then | |
3283 | Result := True; | |
3284 | elsif CR = NE or else CR = GT or else CR = LT then | |
3285 | Result := False; | |
3286 | else | |
45fc7ddb HK |
3287 | return; |
3288 | end if; | |
3289 | ||
634a926b AC |
3290 | when N_Op_Ge => |
3291 | if CR = GT or else CR = EQ or else CR = GE then | |
3292 | Result := True; | |
3293 | elsif CR = LT then | |
3294 | Result := False; | |
3295 | else | |
45fc7ddb HK |
3296 | return; |
3297 | end if; | |
996ae0b0 | 3298 | |
634a926b AC |
3299 | when N_Op_Gt => |
3300 | if CR = GT then | |
3301 | Result := True; | |
3302 | elsif CR = EQ or else CR = LT or else CR = LE then | |
3303 | Result := False; | |
3304 | else | |
3305 | return; | |
3306 | end if; | |
45fc7ddb | 3307 | |
634a926b AC |
3308 | when N_Op_Le => |
3309 | if CR = LT or else CR = EQ or else CR = LE then | |
3310 | Result := True; | |
3311 | elsif CR = GT then | |
3312 | Result := False; | |
3313 | else | |
3314 | return; | |
3315 | end if; | |
45fc7ddb | 3316 | |
634a926b AC |
3317 | when N_Op_Lt => |
3318 | if CR = LT then | |
3319 | Result := True; | |
3320 | elsif CR = EQ or else CR = GT or else CR = GE then | |
3321 | Result := False; | |
3322 | else | |
3323 | return; | |
3324 | end if; | |
45fc7ddb | 3325 | |
634a926b AC |
3326 | when N_Op_Ne => |
3327 | if CR = NE or else CR = GT or else CR = LT then | |
3328 | Result := True; | |
3329 | elsif CR = EQ then | |
3330 | Result := False; | |
3331 | else | |
45fc7ddb HK |
3332 | return; |
3333 | end if; | |
3334 | ||
634a926b AC |
3335 | when others => |
3336 | raise Program_Error; | |
3337 | end case; | |
45fc7ddb | 3338 | |
634a926b AC |
3339 | -- Determine the potential outcome of the relation assuming the |
3340 | -- operands are valid and emit a warning when the relation yields | |
3341 | -- True or False only in the presence of invalid values. | |
3fbbbd1e | 3342 | |
634a926b | 3343 | Warn_On_Constant_Valid_Condition (N); |
e49de265 | 3344 | |
634a926b AC |
3345 | Fold_Uint (N, Test (Result), Is_Static); |
3346 | end Fold_General_Op; | |
e49de265 | 3347 | |
634a926b AC |
3348 | ------------------------- |
3349 | -- Fold_Static_Real_Op -- | |
3350 | ------------------------- | |
45fc7ddb | 3351 | |
634a926b AC |
3352 | procedure Fold_Static_Real_Op is |
3353 | Left_Real : constant Ureal := Expr_Value_R (Left); | |
3354 | Right_Real : constant Ureal := Expr_Value_R (Right); | |
3355 | Result : Boolean; | |
996ae0b0 | 3356 | |
634a926b AC |
3357 | begin |
3358 | case Nkind (N) is | |
3359 | when N_Op_Eq => Result := (Left_Real = Right_Real); | |
3360 | when N_Op_Ge => Result := (Left_Real >= Right_Real); | |
3361 | when N_Op_Gt => Result := (Left_Real > Right_Real); | |
3362 | when N_Op_Le => Result := (Left_Real <= Right_Real); | |
3363 | when N_Op_Lt => Result := (Left_Real < Right_Real); | |
3364 | when N_Op_Ne => Result := (Left_Real /= Right_Real); | |
3365 | when others => raise Program_Error; | |
3366 | end case; | |
3367 | ||
3368 | Fold_Uint (N, Test (Result), True); | |
3369 | end Fold_Static_Real_Op; | |
8a95f4e8 | 3370 | |
634a926b AC |
3371 | ------------------- |
3372 | -- Static_Length -- | |
3373 | ------------------- | |
8a95f4e8 | 3374 | |
634a926b AC |
3375 | function Static_Length (Expr : Node_Id) return Uint is |
3376 | Cons1 : Uint; | |
3377 | Cons2 : Uint; | |
3378 | Ent1 : Entity_Id; | |
3379 | Ent2 : Entity_Id; | |
3380 | Kind1 : Character; | |
3381 | Kind2 : Character; | |
3382 | Typ : Entity_Id; | |
8a95f4e8 | 3383 | |
634a926b AC |
3384 | begin |
3385 | -- First easy case string literal | |
8a95f4e8 | 3386 | |
634a926b AC |
3387 | if Nkind (Expr) = N_String_Literal then |
3388 | return UI_From_Int (String_Length (Strval (Expr))); | |
45fc7ddb | 3389 | |
634a926b | 3390 | -- Second easy case, not constrained subtype, so no length |
45fc7ddb | 3391 | |
634a926b AC |
3392 | elsif not Is_Constrained (Etype (Expr)) then |
3393 | return Uint_Minus_1; | |
3394 | end if; | |
45fc7ddb | 3395 | |
634a926b | 3396 | -- General case |
45fc7ddb | 3397 | |
634a926b | 3398 | Typ := Etype (First_Index (Etype (Expr))); |
45fc7ddb | 3399 | |
634a926b | 3400 | -- The simple case, both bounds are known at compile time |
45fc7ddb | 3401 | |
634a926b AC |
3402 | if Is_Discrete_Type (Typ) |
3403 | and then Compile_Time_Known_Value (Type_Low_Bound (Typ)) | |
3404 | and then Compile_Time_Known_Value (Type_High_Bound (Typ)) | |
3405 | then | |
3406 | return | |
3407 | UI_Max (Uint_0, Expr_Value (Type_High_Bound (Typ)) - | |
3408 | Expr_Value (Type_Low_Bound (Typ)) + 1); | |
3409 | end if; | |
45fc7ddb | 3410 | |
634a926b AC |
3411 | -- A more complex case, where the bounds are of the form X [+/- K1] |
3412 | -- .. X [+/- K2]), where X is an expression that is either A'First or | |
3413 | -- A'Last (with A an entity name), or X is an entity name, and the | |
3414 | -- two X's are the same and K1 and K2 are known at compile time, in | |
3415 | -- this case, the length can also be computed at compile time, even | |
3416 | -- though the bounds are not known. A common case of this is e.g. | |
3417 | -- (X'First .. X'First+5). | |
3418 | ||
3419 | Decompose_Expr | |
3420 | (Original_Node (Type_Low_Bound (Typ)), Ent1, Kind1, Cons1); | |
3421 | Decompose_Expr | |
3422 | (Original_Node (Type_High_Bound (Typ)), Ent2, Kind2, Cons2); | |
3423 | ||
3424 | if Present (Ent1) and then Ent1 = Ent2 and then Kind1 = Kind2 then | |
3425 | return Cons2 - Cons1 + 1; | |
3426 | else | |
3427 | return Uint_Minus_1; | |
3428 | end if; | |
3429 | end Static_Length; | |
45fc7ddb | 3430 | |
634a926b | 3431 | -- Local variables |
45fc7ddb | 3432 | |
634a926b AC |
3433 | Left_Typ : constant Entity_Id := Etype (Left); |
3434 | Right_Typ : constant Entity_Id := Etype (Right); | |
3435 | Fold : Boolean; | |
3436 | Left_Len : Uint; | |
3437 | Op_Typ : Entity_Id := Empty; | |
3438 | Right_Len : Uint; | |
996ae0b0 | 3439 | |
634a926b | 3440 | Is_Static_Expression : Boolean; |
45fc7ddb | 3441 | |
634a926b | 3442 | -- Start of processing for Eval_Relational_Op |
996ae0b0 | 3443 | |
634a926b AC |
3444 | begin |
3445 | -- One special case to deal with first. If we can tell that the result | |
3446 | -- will be false because the lengths of one or more index subtypes are | |
3447 | -- compile time known and different, then we can replace the entire | |
3448 | -- result by False. We only do this for one dimensional arrays, because | |
3449 | -- the case of multi-dimensional arrays is rare and too much trouble. If | |
3450 | -- one of the operands is an illegal aggregate, its type might still be | |
3451 | -- an arbitrary composite type, so nothing to do. | |
45fc7ddb | 3452 | |
634a926b AC |
3453 | if Is_Array_Type (Left_Typ) |
3454 | and then Left_Typ /= Any_Composite | |
3455 | and then Number_Dimensions (Left_Typ) = 1 | |
3456 | and then Nkind_In (N, N_Op_Eq, N_Op_Ne) | |
3457 | then | |
3458 | if Raises_Constraint_Error (Left) | |
3459 | or else | |
3460 | Raises_Constraint_Error (Right) | |
3461 | then | |
3462 | return; | |
996ae0b0 | 3463 | |
634a926b AC |
3464 | -- OK, we have the case where we may be able to do this fold |
3465 | ||
3466 | else | |
3467 | Left_Len := Static_Length (Left); | |
3468 | Right_Len := Static_Length (Right); | |
3469 | ||
3470 | if Left_Len /= Uint_Minus_1 | |
3471 | and then Right_Len /= Uint_Minus_1 | |
3472 | and then Left_Len /= Right_Len | |
996ae0b0 | 3473 | then |
fbf5a39b | 3474 | Fold_Uint (N, Test (Nkind (N) = N_Op_Ne), False); |
996ae0b0 RK |
3475 | Warn_On_Known_Condition (N); |
3476 | return; | |
3477 | end if; | |
634a926b | 3478 | end if; |
80298c3b | 3479 | |
634a926b | 3480 | -- General case |
996ae0b0 | 3481 | |
634a926b AC |
3482 | else |
3483 | -- Initialize the value of Is_Static_Expression. The value of Fold | |
3484 | -- returned by Test_Expression_Is_Foldable is not needed since, even | |
3485 | -- when some operand is a variable, we can still perform the static | |
3486 | -- evaluation of the expression in some cases (for example, for a | |
3487 | -- variable of a subtype of Integer we statically know that any value | |
3488 | -- stored in such variable is smaller than Integer'Last). | |
5df1266a AC |
3489 | |
3490 | Test_Expression_Is_Foldable | |
634a926b | 3491 | (N, Left, Right, Is_Static_Expression, Fold); |
5df1266a | 3492 | |
634a926b AC |
3493 | -- Only comparisons of scalars can give static results. A comparison |
3494 | -- of strings never yields a static result, even if both operands are | |
3495 | -- static strings, except that as noted above, we allow equality and | |
3496 | -- inequality for strings. | |
fc3a3f3b | 3497 | |
634a926b | 3498 | if Is_String_Type (Left_Typ) |
fc3a3f3b RD |
3499 | and then not Comes_From_Source (N) |
3500 | and then Nkind_In (N, N_Op_Eq, N_Op_Ne) | |
3501 | then | |
3502 | null; | |
5df1266a | 3503 | |
634a926b | 3504 | elsif not Is_Scalar_Type (Left_Typ) then |
5df1266a AC |
3505 | Is_Static_Expression := False; |
3506 | Set_Is_Static_Expression (N, False); | |
3507 | end if; | |
d7567964 | 3508 | |
5df1266a AC |
3509 | -- For operators on universal numeric types called as functions with |
3510 | -- an explicit scope, determine appropriate specific numeric type, | |
3511 | -- and diagnose possible ambiguity. | |
d7567964 | 3512 | |
634a926b | 3513 | if Is_Universal_Numeric_Type (Left_Typ) |
5df1266a | 3514 | and then |
634a926b | 3515 | Is_Universal_Numeric_Type (Right_Typ) |
5df1266a | 3516 | then |
634a926b | 3517 | Op_Typ := Find_Universal_Operator_Type (N); |
5df1266a | 3518 | end if; |
996ae0b0 | 3519 | |
634a926b | 3520 | -- Attempt to fold the relational operator |
996ae0b0 | 3521 | |
634a926b AC |
3522 | if Is_Static_Expression and then Is_Real_Type (Left_Typ) then |
3523 | Fold_Static_Real_Op; | |
5df1266a | 3524 | else |
634a926b | 3525 | Fold_General_Op (Is_Static_Expression); |
5df1266a | 3526 | end if; |
634a926b | 3527 | end if; |
996ae0b0 | 3528 | |
d7567964 | 3529 | -- For the case of a folded relational operator on a specific numeric |
634a926b | 3530 | -- type, freeze the operand type now. |
d7567964 | 3531 | |
634a926b AC |
3532 | if Present (Op_Typ) then |
3533 | Freeze_Before (N, Op_Typ); | |
d7567964 TQ |
3534 | end if; |
3535 | ||
996ae0b0 RK |
3536 | Warn_On_Known_Condition (N); |
3537 | end Eval_Relational_Op; | |
3538 | ||
3539 | ---------------- | |
3540 | -- Eval_Shift -- | |
3541 | ---------------- | |
3542 | ||
22cb89b5 AC |
3543 | -- Shift operations are intrinsic operations that can never be static, so |
3544 | -- the only processing required is to perform the required check for a non | |
3545 | -- static context for the two operands. | |
996ae0b0 RK |
3546 | |
3547 | -- Actually we could do some compile time evaluation here some time ??? | |
3548 | ||
3549 | procedure Eval_Shift (N : Node_Id) is | |
3550 | begin | |
3551 | Check_Non_Static_Context (Left_Opnd (N)); | |
3552 | Check_Non_Static_Context (Right_Opnd (N)); | |
3553 | end Eval_Shift; | |
3554 | ||
3555 | ------------------------ | |
3556 | -- Eval_Short_Circuit -- | |
3557 | ------------------------ | |
3558 | ||
22cb89b5 AC |
3559 | -- A short circuit operation is potentially static if both operands are |
3560 | -- potentially static (RM 4.9 (13)). | |
996ae0b0 RK |
3561 | |
3562 | procedure Eval_Short_Circuit (N : Node_Id) is | |
3563 | Kind : constant Node_Kind := Nkind (N); | |
3564 | Left : constant Node_Id := Left_Opnd (N); | |
3565 | Right : constant Node_Id := Right_Opnd (N); | |
3566 | Left_Int : Uint; | |
4d777a71 AC |
3567 | |
3568 | Rstat : constant Boolean := | |
3569 | Is_Static_Expression (Left) | |
3570 | and then | |
3571 | Is_Static_Expression (Right); | |
996ae0b0 RK |
3572 | |
3573 | begin | |
3574 | -- Short circuit operations are never static in Ada 83 | |
3575 | ||
22cb89b5 | 3576 | if Ada_Version = Ada_83 and then Comes_From_Source (N) then |
996ae0b0 RK |
3577 | Check_Non_Static_Context (Left); |
3578 | Check_Non_Static_Context (Right); | |
3579 | return; | |
3580 | end if; | |
3581 | ||
3582 | -- Now look at the operands, we can't quite use the normal call to | |
3583 | -- Test_Expression_Is_Foldable here because short circuit operations | |
3584 | -- are a special case, they can still be foldable, even if the right | |
3585 | -- operand raises constraint error. | |
3586 | ||
22cb89b5 AC |
3587 | -- If either operand is Any_Type, just propagate to result and do not |
3588 | -- try to fold, this prevents cascaded errors. | |
996ae0b0 RK |
3589 | |
3590 | if Etype (Left) = Any_Type or else Etype (Right) = Any_Type then | |
3591 | Set_Etype (N, Any_Type); | |
3592 | return; | |
3593 | ||
3594 | -- If left operand raises constraint error, then replace node N with | |
3595 | -- the raise constraint error node, and we are obviously not foldable. | |
3596 | -- Is_Static_Expression is set from the two operands in the normal way, | |
3597 | -- and we check the right operand if it is in a non-static context. | |
3598 | ||
3599 | elsif Raises_Constraint_Error (Left) then | |
3600 | if not Rstat then | |
3601 | Check_Non_Static_Context (Right); | |
3602 | end if; | |
3603 | ||
3604 | Rewrite_In_Raise_CE (N, Left); | |
3605 | Set_Is_Static_Expression (N, Rstat); | |
3606 | return; | |
3607 | ||
3608 | -- If the result is not static, then we won't in any case fold | |
3609 | ||
3610 | elsif not Rstat then | |
3611 | Check_Non_Static_Context (Left); | |
3612 | Check_Non_Static_Context (Right); | |
3613 | return; | |
3614 | end if; | |
3615 | ||
3616 | -- Here the result is static, note that, unlike the normal processing | |
3617 | -- in Test_Expression_Is_Foldable, we did *not* check above to see if | |
3618 | -- the right operand raises constraint error, that's because it is not | |
3619 | -- significant if the left operand is decisive. | |
3620 | ||
3621 | Set_Is_Static_Expression (N); | |
3622 | ||
3623 | -- It does not matter if the right operand raises constraint error if | |
3624 | -- it will not be evaluated. So deal specially with the cases where | |
3625 | -- the right operand is not evaluated. Note that we will fold these | |
3626 | -- cases even if the right operand is non-static, which is fine, but | |
3627 | -- of course in these cases the result is not potentially static. | |
3628 | ||
3629 | Left_Int := Expr_Value (Left); | |
3630 | ||
3631 | if (Kind = N_And_Then and then Is_False (Left_Int)) | |
db318f46 | 3632 | or else |
4d777a71 | 3633 | (Kind = N_Or_Else and then Is_True (Left_Int)) |
996ae0b0 | 3634 | then |
fbf5a39b | 3635 | Fold_Uint (N, Left_Int, Rstat); |
996ae0b0 RK |
3636 | return; |
3637 | end if; | |
3638 | ||
3639 | -- If first operand not decisive, then it does matter if the right | |
3640 | -- operand raises constraint error, since it will be evaluated, so | |
3641 | -- we simply replace the node with the right operand. Note that this | |
3642 | -- properly propagates Is_Static_Expression and Raises_Constraint_Error | |
3643 | -- (both are set to True in Right). | |
3644 | ||
3645 | if Raises_Constraint_Error (Right) then | |
3646 | Rewrite_In_Raise_CE (N, Right); | |
3647 | Check_Non_Static_Context (Left); | |
3648 | return; | |
3649 | end if; | |
3650 | ||
3651 | -- Otherwise the result depends on the right operand | |
3652 | ||
fbf5a39b | 3653 | Fold_Uint (N, Expr_Value (Right), Rstat); |
996ae0b0 | 3654 | return; |
996ae0b0 RK |
3655 | end Eval_Short_Circuit; |
3656 | ||
3657 | ---------------- | |
3658 | -- Eval_Slice -- | |
3659 | ---------------- | |
3660 | ||
22cb89b5 AC |
3661 | -- Slices can never be static, so the only processing required is to check |
3662 | -- for non-static context if an explicit range is given. | |
996ae0b0 RK |
3663 | |
3664 | procedure Eval_Slice (N : Node_Id) is | |
3665 | Drange : constant Node_Id := Discrete_Range (N); | |
80298c3b | 3666 | |
996ae0b0 RK |
3667 | begin |
3668 | if Nkind (Drange) = N_Range then | |
3669 | Check_Non_Static_Context (Low_Bound (Drange)); | |
3670 | Check_Non_Static_Context (High_Bound (Drange)); | |
3671 | end if; | |
cd2fb920 | 3672 | |
22cb89b5 | 3673 | -- A slice of the form A (subtype), when the subtype is the index of |
cd2fb920 ES |
3674 | -- the type of A, is redundant, the slice can be replaced with A, and |
3675 | -- this is worth a warning. | |
3676 | ||
3677 | if Is_Entity_Name (Prefix (N)) then | |
3678 | declare | |
3679 | E : constant Entity_Id := Entity (Prefix (N)); | |
3680 | T : constant Entity_Id := Etype (E); | |
80298c3b | 3681 | |
cd2fb920 ES |
3682 | begin |
3683 | if Ekind (E) = E_Constant | |
3684 | and then Is_Array_Type (T) | |
3685 | and then Is_Entity_Name (Drange) | |
3686 | then | |
3687 | if Is_Entity_Name (Original_Node (First_Index (T))) | |
3688 | and then Entity (Original_Node (First_Index (T))) | |
3689 | = Entity (Drange) | |
3690 | then | |
3691 | if Warn_On_Redundant_Constructs then | |
324ac540 | 3692 | Error_Msg_N ("redundant slice denotes whole array?r?", N); |
cd2fb920 ES |
3693 | end if; |
3694 | ||
324ac540 | 3695 | -- The following might be a useful optimization??? |
cd2fb920 ES |
3696 | |
3697 | -- Rewrite (N, New_Occurrence_Of (E, Sloc (N))); | |
3698 | end if; | |
3699 | end if; | |
3700 | end; | |
3701 | end if; | |
996ae0b0 RK |
3702 | end Eval_Slice; |
3703 | ||
3704 | ------------------------- | |
3705 | -- Eval_String_Literal -- | |
3706 | ------------------------- | |
3707 | ||
3708 | procedure Eval_String_Literal (N : Node_Id) is | |
91b1417d AC |
3709 | Typ : constant Entity_Id := Etype (N); |
3710 | Bas : constant Entity_Id := Base_Type (Typ); | |
3711 | Xtp : Entity_Id; | |
3712 | Len : Nat; | |
3713 | Lo : Node_Id; | |
996ae0b0 RK |
3714 | |
3715 | begin | |
3716 | -- Nothing to do if error type (handles cases like default expressions | |
22cb89b5 | 3717 | -- or generics where we have not yet fully resolved the type). |
996ae0b0 | 3718 | |
91b1417d | 3719 | if Bas = Any_Type or else Bas = Any_String then |
996ae0b0 | 3720 | return; |
91b1417d | 3721 | end if; |
996ae0b0 RK |
3722 | |
3723 | -- String literals are static if the subtype is static (RM 4.9(2)), so | |
3724 | -- reset the static expression flag (it was set unconditionally in | |
3725 | -- Analyze_String_Literal) if the subtype is non-static. We tell if | |
3726 | -- the subtype is static by looking at the lower bound. | |
3727 | ||
91b1417d AC |
3728 | if Ekind (Typ) = E_String_Literal_Subtype then |
3729 | if not Is_OK_Static_Expression (String_Literal_Low_Bound (Typ)) then | |
3730 | Set_Is_Static_Expression (N, False); | |
3731 | return; | |
3732 | end if; | |
3733 | ||
3734 | -- Here if Etype of string literal is normal Etype (not yet possible, | |
22cb89b5 | 3735 | -- but may be possible in future). |
91b1417d AC |
3736 | |
3737 | elsif not Is_OK_Static_Expression | |
80298c3b | 3738 | (Type_Low_Bound (Etype (First_Index (Typ)))) |
91b1417d | 3739 | then |
996ae0b0 | 3740 | Set_Is_Static_Expression (N, False); |
91b1417d AC |
3741 | return; |
3742 | end if; | |
996ae0b0 | 3743 | |
91b1417d AC |
3744 | -- If original node was a type conversion, then result if non-static |
3745 | ||
3746 | if Nkind (Original_Node (N)) = N_Type_Conversion then | |
996ae0b0 | 3747 | Set_Is_Static_Expression (N, False); |
91b1417d AC |
3748 | return; |
3749 | end if; | |
996ae0b0 | 3750 | |
22cb89b5 AC |
3751 | -- Test for illegal Ada 95 cases. A string literal is illegal in Ada 95 |
3752 | -- if its bounds are outside the index base type and this index type is | |
3753 | -- static. This can happen in only two ways. Either the string literal | |
bc3c2eca AC |
3754 | -- is too long, or it is null, and the lower bound is type'First. Either |
3755 | -- way it is the upper bound that is out of range of the index type. | |
3756 | ||
0ab80019 | 3757 | if Ada_Version >= Ada_95 then |
bc3c2eca | 3758 | if Is_Standard_String_Type (Bas) then |
91b1417d | 3759 | Xtp := Standard_Positive; |
996ae0b0 | 3760 | else |
91b1417d | 3761 | Xtp := Etype (First_Index (Bas)); |
996ae0b0 RK |
3762 | end if; |
3763 | ||
91b1417d AC |
3764 | if Ekind (Typ) = E_String_Literal_Subtype then |
3765 | Lo := String_Literal_Low_Bound (Typ); | |
3766 | else | |
3767 | Lo := Type_Low_Bound (Etype (First_Index (Typ))); | |
3768 | end if; | |
3769 | ||
354c3840 AC |
3770 | -- Check for string too long |
3771 | ||
91b1417d AC |
3772 | Len := String_Length (Strval (N)); |
3773 | ||
3774 | if UI_From_Int (Len) > String_Type_Len (Bas) then | |
354c3840 AC |
3775 | |
3776 | -- Issue message. Note that this message is a warning if the | |
3777 | -- string literal is not marked as static (happens in some cases | |
3778 | -- of folding strings known at compile time, but not static). | |
3779 | -- Furthermore in such cases, we reword the message, since there | |
a90bd866 | 3780 | -- is no string literal in the source program. |
354c3840 AC |
3781 | |
3782 | if Is_Static_Expression (N) then | |
3783 | Apply_Compile_Time_Constraint_Error | |
3784 | (N, "string literal too long for}", CE_Length_Check_Failed, | |
3785 | Ent => Bas, | |
3786 | Typ => First_Subtype (Bas)); | |
3787 | else | |
3788 | Apply_Compile_Time_Constraint_Error | |
3789 | (N, "string value too long for}", CE_Length_Check_Failed, | |
3790 | Ent => Bas, | |
3791 | Typ => First_Subtype (Bas), | |
3792 | Warn => True); | |
3793 | end if; | |
3794 | ||
3795 | -- Test for null string not allowed | |
996ae0b0 | 3796 | |
91b1417d AC |
3797 | elsif Len = 0 |
3798 | and then not Is_Generic_Type (Xtp) | |
3799 | and then | |
3800 | Expr_Value (Lo) = Expr_Value (Type_Low_Bound (Base_Type (Xtp))) | |
996ae0b0 | 3801 | then |
354c3840 AC |
3802 | -- Same specialization of message |
3803 | ||
3804 | if Is_Static_Expression (N) then | |
3805 | Apply_Compile_Time_Constraint_Error | |
3806 | (N, "null string literal not allowed for}", | |
3807 | CE_Length_Check_Failed, | |
3808 | Ent => Bas, | |
3809 | Typ => First_Subtype (Bas)); | |
3810 | else | |
3811 | Apply_Compile_Time_Constraint_Error | |
3812 | (N, "null string value not allowed for}", | |
3813 | CE_Length_Check_Failed, | |
3814 | Ent => Bas, | |
3815 | Typ => First_Subtype (Bas), | |
3816 | Warn => True); | |
3817 | end if; | |
996ae0b0 RK |
3818 | end if; |
3819 | end if; | |
996ae0b0 RK |
3820 | end Eval_String_Literal; |
3821 | ||
3822 | -------------------------- | |
3823 | -- Eval_Type_Conversion -- | |
3824 | -------------------------- | |
3825 | ||
3826 | -- A type conversion is potentially static if its subtype mark is for a | |
3827 | -- static scalar subtype, and its operand expression is potentially static | |
22cb89b5 | 3828 | -- (RM 4.9(10)). |
996ae0b0 RK |
3829 | |
3830 | procedure Eval_Type_Conversion (N : Node_Id) is | |
3831 | Operand : constant Node_Id := Expression (N); | |
3832 | Source_Type : constant Entity_Id := Etype (Operand); | |
3833 | Target_Type : constant Entity_Id := Etype (N); | |
3834 | ||
996ae0b0 | 3835 | function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean; |
22cb89b5 AC |
3836 | -- Returns true if type T is an integer type, or if it is a fixed-point |
3837 | -- type to be treated as an integer (i.e. the flag Conversion_OK is set | |
3838 | -- on the conversion node). | |
996ae0b0 RK |
3839 | |
3840 | function To_Be_Treated_As_Real (T : Entity_Id) return Boolean; | |
3841 | -- Returns true if type T is a floating-point type, or if it is a | |
3842 | -- fixed-point type that is not to be treated as an integer (i.e. the | |
3843 | -- flag Conversion_OK is not set on the conversion node). | |
3844 | ||
fbf5a39b AC |
3845 | ------------------------------ |
3846 | -- To_Be_Treated_As_Integer -- | |
3847 | ------------------------------ | |
3848 | ||
996ae0b0 RK |
3849 | function To_Be_Treated_As_Integer (T : Entity_Id) return Boolean is |
3850 | begin | |
3851 | return | |
3852 | Is_Integer_Type (T) | |
3853 | or else (Is_Fixed_Point_Type (T) and then Conversion_OK (N)); | |
3854 | end To_Be_Treated_As_Integer; | |
3855 | ||
fbf5a39b AC |
3856 | --------------------------- |
3857 | -- To_Be_Treated_As_Real -- | |
3858 | --------------------------- | |
3859 | ||
996ae0b0 RK |
3860 | function To_Be_Treated_As_Real (T : Entity_Id) return Boolean is |
3861 | begin | |
3862 | return | |
3863 | Is_Floating_Point_Type (T) | |
3864 | or else (Is_Fixed_Point_Type (T) and then not Conversion_OK (N)); | |
3865 | end To_Be_Treated_As_Real; | |
3866 | ||
48bb06a7 AC |
3867 | -- Local variables |
3868 | ||
3869 | Fold : Boolean; | |
3870 | Stat : Boolean; | |
3871 | ||
996ae0b0 RK |
3872 | -- Start of processing for Eval_Type_Conversion |
3873 | ||
3874 | begin | |
82c80734 | 3875 | -- Cannot fold if target type is non-static or if semantic error |
996ae0b0 RK |
3876 | |
3877 | if not Is_Static_Subtype (Target_Type) then | |
3878 | Check_Non_Static_Context (Operand); | |
3879 | return; | |
996ae0b0 RK |
3880 | elsif Error_Posted (N) then |
3881 | return; | |
3882 | end if; | |
3883 | ||
3884 | -- If not foldable we are done | |
3885 | ||
3886 | Test_Expression_Is_Foldable (N, Operand, Stat, Fold); | |
3887 | ||
3888 | if not Fold then | |
3889 | return; | |
3890 | ||
3891 | -- Don't try fold if target type has constraint error bounds | |
3892 | ||
3893 | elsif not Is_OK_Static_Subtype (Target_Type) then | |
3894 | Set_Raises_Constraint_Error (N); | |
3895 | return; | |
3896 | end if; | |
3897 | ||
3898 | -- Remaining processing depends on operand types. Note that in the | |
3899 | -- following type test, fixed-point counts as real unless the flag | |
3900 | -- Conversion_OK is set, in which case it counts as integer. | |
3901 | ||
82c80734 | 3902 | -- Fold conversion, case of string type. The result is not static |
996ae0b0 RK |
3903 | |
3904 | if Is_String_Type (Target_Type) then | |
b11e8d6f | 3905 | Fold_Str (N, Strval (Get_String_Val (Operand)), Static => False); |
996ae0b0 RK |
3906 | return; |
3907 | ||
3908 | -- Fold conversion, case of integer target type | |
3909 | ||
3910 | elsif To_Be_Treated_As_Integer (Target_Type) then | |
3911 | declare | |
3912 | Result : Uint; | |
3913 | ||
3914 | begin | |
3915 | -- Integer to integer conversion | |
3916 | ||
3917 | if To_Be_Treated_As_Integer (Source_Type) then | |
3918 | Result := Expr_Value (Operand); | |
3919 | ||
3920 | -- Real to integer conversion | |
3921 | ||
3922 | else | |
3923 | Result := UR_To_Uint (Expr_Value_R (Operand)); | |
3924 | end if; | |
3925 | ||
3926 | -- If fixed-point type (Conversion_OK must be set), then the | |
3927 | -- result is logically an integer, but we must replace the | |
3928 | -- conversion with the corresponding real literal, since the | |
3929 | -- type from a semantic point of view is still fixed-point. | |
3930 | ||
3931 | if Is_Fixed_Point_Type (Target_Type) then | |
3932 | Fold_Ureal | |
fbf5a39b | 3933 | (N, UR_From_Uint (Result) * Small_Value (Target_Type), Stat); |
996ae0b0 RK |
3934 | |
3935 | -- Otherwise result is integer literal | |
3936 | ||
3937 | else | |
fbf5a39b | 3938 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
3939 | end if; |
3940 | end; | |
3941 | ||
3942 | -- Fold conversion, case of real target type | |
3943 | ||
3944 | elsif To_Be_Treated_As_Real (Target_Type) then | |
3945 | declare | |
3946 | Result : Ureal; | |
3947 | ||
3948 | begin | |
3949 | if To_Be_Treated_As_Real (Source_Type) then | |
3950 | Result := Expr_Value_R (Operand); | |
3951 | else | |
3952 | Result := UR_From_Uint (Expr_Value (Operand)); | |
3953 | end if; | |
3954 | ||
fbf5a39b | 3955 | Fold_Ureal (N, Result, Stat); |
996ae0b0 RK |
3956 | end; |
3957 | ||
3958 | -- Enumeration types | |
3959 | ||
3960 | else | |
fbf5a39b | 3961 | Fold_Uint (N, Expr_Value (Operand), Stat); |
996ae0b0 RK |
3962 | end if; |
3963 | ||
c800f862 | 3964 | if Is_Out_Of_Range (N, Etype (N), Assume_Valid => True) then |
996ae0b0 RK |
3965 | Out_Of_Range (N); |
3966 | end if; | |
3967 | ||
3968 | end Eval_Type_Conversion; | |
3969 | ||
3970 | ------------------- | |
3971 | -- Eval_Unary_Op -- | |
3972 | ------------------- | |
3973 | ||
3974 | -- Predefined unary operators are static functions (RM 4.9(20)) and thus | |
22cb89b5 | 3975 | -- are potentially static if the operand is potentially static (RM 4.9(7)). |
996ae0b0 RK |
3976 | |
3977 | procedure Eval_Unary_Op (N : Node_Id) is | |
3978 | Right : constant Node_Id := Right_Opnd (N); | |
d7567964 | 3979 | Otype : Entity_Id := Empty; |
996ae0b0 RK |
3980 | Stat : Boolean; |
3981 | Fold : Boolean; | |
3982 | ||
3983 | begin | |
3984 | -- If not foldable we are done | |
3985 | ||
3986 | Test_Expression_Is_Foldable (N, Right, Stat, Fold); | |
3987 | ||
3988 | if not Fold then | |
3989 | return; | |
3990 | end if; | |
3991 | ||
602a7ec0 | 3992 | if Etype (Right) = Universal_Integer |
ae77c68b AC |
3993 | or else |
3994 | Etype (Right) = Universal_Real | |
602a7ec0 | 3995 | then |
d7567964 | 3996 | Otype := Find_Universal_Operator_Type (N); |
602a7ec0 AC |
3997 | end if; |
3998 | ||
996ae0b0 RK |
3999 | -- Fold for integer case |
4000 | ||
4001 | if Is_Integer_Type (Etype (N)) then | |
4002 | declare | |
4003 | Rint : constant Uint := Expr_Value (Right); | |
4004 | Result : Uint; | |
4005 | ||
4006 | begin | |
4007 | -- In the case of modular unary plus and abs there is no need | |
4008 | -- to adjust the result of the operation since if the original | |
4009 | -- operand was in bounds the result will be in the bounds of the | |
4010 | -- modular type. However, in the case of modular unary minus the | |
4011 | -- result may go out of the bounds of the modular type and needs | |
4012 | -- adjustment. | |
4013 | ||
4014 | if Nkind (N) = N_Op_Plus then | |
4015 | Result := Rint; | |
4016 | ||
4017 | elsif Nkind (N) = N_Op_Minus then | |
4018 | if Is_Modular_Integer_Type (Etype (N)) then | |
4019 | Result := (-Rint) mod Modulus (Etype (N)); | |
4020 | else | |
4021 | Result := (-Rint); | |
4022 | end if; | |
4023 | ||
4024 | else | |
4025 | pragma Assert (Nkind (N) = N_Op_Abs); | |
4026 | Result := abs Rint; | |
4027 | end if; | |
4028 | ||
fbf5a39b | 4029 | Fold_Uint (N, Result, Stat); |
996ae0b0 RK |
4030 | end; |
4031 | ||
4032 | -- Fold for real case | |
4033 | ||
4034 | elsif Is_Real_Type (Etype (N)) then | |
4035 | declare | |
4036 | Rreal : constant Ureal := Expr_Value_R (Right); | |
4037 | Result : Ureal; | |
4038 | ||
4039 | begin | |
4040 | if Nkind (N) = N_Op_Plus then | |
4041 | Result := Rreal; | |
996ae0b0 RK |
4042 | elsif Nkind (N) = N_Op_Minus then |
4043 | Result := UR_Negate (Rreal); | |
996ae0b0 RK |
4044 | else |
4045 | pragma Assert (Nkind (N) = N_Op_Abs); | |
4046 | Result := abs Rreal; | |
4047 | end if; | |
4048 | ||
fbf5a39b | 4049 | Fold_Ureal (N, Result, Stat); |
996ae0b0 RK |
4050 | end; |
4051 | end if; | |
d7567964 TQ |
4052 | |
4053 | -- If the operator was resolved to a specific type, make sure that type | |
4054 | -- is frozen even if the expression is folded into a literal (which has | |
4055 | -- a universal type). | |
4056 | ||
4057 | if Present (Otype) then | |
4058 | Freeze_Before (N, Otype); | |
4059 | end if; | |
996ae0b0 RK |
4060 | end Eval_Unary_Op; |
4061 | ||
4062 | ------------------------------- | |
4063 | -- Eval_Unchecked_Conversion -- | |
4064 | ------------------------------- | |
4065 | ||
4066 | -- Unchecked conversions can never be static, so the only required | |
4067 | -- processing is to check for a non-static context for the operand. | |
4068 | ||
4069 | procedure Eval_Unchecked_Conversion (N : Node_Id) is | |
4070 | begin | |
4071 | Check_Non_Static_Context (Expression (N)); | |
4072 | end Eval_Unchecked_Conversion; | |
4073 | ||
4074 | -------------------- | |
4075 | -- Expr_Rep_Value -- | |
4076 | -------------------- | |
4077 | ||
4078 | function Expr_Rep_Value (N : Node_Id) return Uint is | |
07fc65c4 GB |
4079 | Kind : constant Node_Kind := Nkind (N); |
4080 | Ent : Entity_Id; | |
996ae0b0 RK |
4081 | |
4082 | begin | |
4083 | if Is_Entity_Name (N) then | |
4084 | Ent := Entity (N); | |
4085 | ||
22cb89b5 AC |
4086 | -- An enumeration literal that was either in the source or created |
4087 | -- as a result of static evaluation. | |
996ae0b0 RK |
4088 | |
4089 | if Ekind (Ent) = E_Enumeration_Literal then | |
4090 | return Enumeration_Rep (Ent); | |
4091 | ||
4092 | -- A user defined static constant | |
4093 | ||
4094 | else | |
4095 | pragma Assert (Ekind (Ent) = E_Constant); | |
4096 | return Expr_Rep_Value (Constant_Value (Ent)); | |
4097 | end if; | |
4098 | ||
22cb89b5 AC |
4099 | -- An integer literal that was either in the source or created as a |
4100 | -- result of static evaluation. | |
996ae0b0 RK |
4101 | |
4102 | elsif Kind = N_Integer_Literal then | |
4103 | return Intval (N); | |
4104 | ||
4105 | -- A real literal for a fixed-point type. This must be the fixed-point | |
4106 | -- case, either the literal is of a fixed-point type, or it is a bound | |
4107 | -- of a fixed-point type, with type universal real. In either case we | |
4108 | -- obtain the desired value from Corresponding_Integer_Value. | |
4109 | ||
4110 | elsif Kind = N_Real_Literal then | |
996ae0b0 RK |
4111 | pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N)))); |
4112 | return Corresponding_Integer_Value (N); | |
4113 | ||
07fc65c4 | 4114 | -- Otherwise must be character literal |
8cbb664e | 4115 | |
996ae0b0 RK |
4116 | else |
4117 | pragma Assert (Kind = N_Character_Literal); | |
4118 | Ent := Entity (N); | |
4119 | ||
22cb89b5 AC |
4120 | -- Since Character literals of type Standard.Character don't have any |
4121 | -- defining character literals built for them, they do not have their | |
4122 | -- Entity set, so just use their Char code. Otherwise for user- | |
4123 | -- defined character literals use their Pos value as usual which is | |
4124 | -- the same as the Rep value. | |
996ae0b0 RK |
4125 | |
4126 | if No (Ent) then | |
82c80734 | 4127 | return Char_Literal_Value (N); |
996ae0b0 RK |
4128 | else |
4129 | return Enumeration_Rep (Ent); | |
4130 | end if; | |
4131 | end if; | |
4132 | end Expr_Rep_Value; | |
4133 | ||
4134 | ---------------- | |
4135 | -- Expr_Value -- | |
4136 | ---------------- | |
4137 | ||
4138 | function Expr_Value (N : Node_Id) return Uint is | |
07fc65c4 GB |
4139 | Kind : constant Node_Kind := Nkind (N); |
4140 | CV_Ent : CV_Entry renames CV_Cache (Nat (N) mod CV_Cache_Size); | |
4141 | Ent : Entity_Id; | |
4142 | Val : Uint; | |
996ae0b0 RK |
4143 | |
4144 | begin | |
13f34a3f RD |
4145 | -- If already in cache, then we know it's compile time known and we can |
4146 | -- return the value that was previously stored in the cache since | |
4147 | -- compile time known values cannot change. | |
07fc65c4 GB |
4148 | |
4149 | if CV_Ent.N = N then | |
4150 | return CV_Ent.V; | |
4151 | end if; | |
4152 | ||
4153 | -- Otherwise proceed to test value | |
4154 | ||
996ae0b0 RK |
4155 | if Is_Entity_Name (N) then |
4156 | Ent := Entity (N); | |
4157 | ||
22cb89b5 AC |
4158 | -- An enumeration literal that was either in the source or created as |
4159 | -- a result of static evaluation. | |
996ae0b0 RK |
4160 | |
4161 | if Ekind (Ent) = E_Enumeration_Literal then | |
07fc65c4 | 4162 | Val := Enumeration_Pos (Ent); |
996ae0b0 RK |
4163 | |
4164 | -- A user defined static constant | |
4165 | ||
4166 | else | |
4167 | pragma Assert (Ekind (Ent) = E_Constant); | |
07fc65c4 | 4168 | Val := Expr_Value (Constant_Value (Ent)); |
996ae0b0 RK |
4169 | end if; |
4170 | ||
22cb89b5 AC |
4171 | -- An integer literal that was either in the source or created as a |
4172 | -- result of static evaluation. | |
996ae0b0 RK |
4173 | |
4174 | elsif Kind = N_Integer_Literal then | |
07fc65c4 | 4175 | Val := Intval (N); |
996ae0b0 RK |
4176 | |
4177 | -- A real literal for a fixed-point type. This must be the fixed-point | |
4178 | -- case, either the literal is of a fixed-point type, or it is a bound | |
4179 | -- of a fixed-point type, with type universal real. In either case we | |
4180 | -- obtain the desired value from Corresponding_Integer_Value. | |
4181 | ||
4182 | elsif Kind = N_Real_Literal then | |
996ae0b0 | 4183 | pragma Assert (Is_Fixed_Point_Type (Underlying_Type (Etype (N)))); |
07fc65c4 | 4184 | Val := Corresponding_Integer_Value (N); |
996ae0b0 | 4185 | |
996ae0b0 RK |
4186 | -- Otherwise must be character literal |
4187 | ||
4188 | else | |
4189 | pragma Assert (Kind = N_Character_Literal); | |
4190 | Ent := Entity (N); | |
4191 | ||
4192 | -- Since Character literals of type Standard.Character don't | |
4193 | -- have any defining character literals built for them, they | |
4194 | -- do not have their Entity set, so just use their Char | |
4195 | -- code. Otherwise for user-defined character literals use | |
4196 | -- their Pos value as usual. | |
4197 | ||
4198 | if No (Ent) then | |
82c80734 | 4199 | Val := Char_Literal_Value (N); |
996ae0b0 | 4200 | else |
07fc65c4 | 4201 | Val := Enumeration_Pos (Ent); |
996ae0b0 RK |
4202 | end if; |
4203 | end if; | |
4204 | ||
07fc65c4 GB |
4205 | -- Come here with Val set to value to be returned, set cache |
4206 | ||
4207 | CV_Ent.N := N; | |
4208 | CV_Ent.V := Val; | |
4209 | return Val; | |
996ae0b0 RK |
4210 | end Expr_Value; |
4211 | ||
4212 | ------------------ | |
4213 | -- Expr_Value_E -- | |
4214 | ------------------ | |
4215 | ||
4216 | function Expr_Value_E (N : Node_Id) return Entity_Id is | |
4217 | Ent : constant Entity_Id := Entity (N); | |
996ae0b0 RK |
4218 | begin |
4219 | if Ekind (Ent) = E_Enumeration_Literal then | |
4220 | return Ent; | |
4221 | else | |
4222 | pragma Assert (Ekind (Ent) = E_Constant); | |
4223 | return Expr_Value_E (Constant_Value (Ent)); | |
4224 | end if; | |
4225 | end Expr_Value_E; | |
4226 | ||
4227 | ------------------ | |
4228 | -- Expr_Value_R -- | |
4229 | ------------------ | |
4230 | ||
4231 | function Expr_Value_R (N : Node_Id) return Ureal is | |
4232 | Kind : constant Node_Kind := Nkind (N); | |
4233 | Ent : Entity_Id; | |
996ae0b0 RK |
4234 | |
4235 | begin | |
4236 | if Kind = N_Real_Literal then | |
4237 | return Realval (N); | |
4238 | ||
4239 | elsif Kind = N_Identifier or else Kind = N_Expanded_Name then | |
4240 | Ent := Entity (N); | |
4241 | pragma Assert (Ekind (Ent) = E_Constant); | |
4242 | return Expr_Value_R (Constant_Value (Ent)); | |
4243 | ||
4244 | elsif Kind = N_Integer_Literal then | |
4245 | return UR_From_Uint (Expr_Value (N)); | |
4246 | ||
7a5b62b0 AC |
4247 | -- Here, we have a node that cannot be interpreted as a compile time |
4248 | -- constant. That is definitely an error. | |
996ae0b0 | 4249 | |
7a5b62b0 AC |
4250 | else |
4251 | raise Program_Error; | |
996ae0b0 | 4252 | end if; |
996ae0b0 RK |
4253 | end Expr_Value_R; |
4254 | ||
4255 | ------------------ | |
4256 | -- Expr_Value_S -- | |
4257 | ------------------ | |
4258 | ||
4259 | function Expr_Value_S (N : Node_Id) return Node_Id is | |
4260 | begin | |
4261 | if Nkind (N) = N_String_Literal then | |
4262 | return N; | |
4263 | else | |
4264 | pragma Assert (Ekind (Entity (N)) = E_Constant); | |
4265 | return Expr_Value_S (Constant_Value (Entity (N))); | |
4266 | end if; | |
4267 | end Expr_Value_S; | |
4268 | ||
74e7891f RD |
4269 | ---------------------------------- |
4270 | -- Find_Universal_Operator_Type -- | |
4271 | ---------------------------------- | |
4272 | ||
4273 | function Find_Universal_Operator_Type (N : Node_Id) return Entity_Id is | |
4274 | PN : constant Node_Id := Parent (N); | |
4275 | Call : constant Node_Id := Original_Node (N); | |
4276 | Is_Int : constant Boolean := Is_Integer_Type (Etype (N)); | |
4277 | ||
4278 | Is_Fix : constant Boolean := | |
4279 | Nkind (N) in N_Binary_Op | |
4280 | and then Nkind (Right_Opnd (N)) /= Nkind (Left_Opnd (N)); | |
4281 | -- A mixed-mode operation in this context indicates the presence of | |
4282 | -- fixed-point type in the designated package. | |
4283 | ||
4284 | Is_Relational : constant Boolean := Etype (N) = Standard_Boolean; | |
4285 | -- Case where N is a relational (or membership) operator (else it is an | |
4286 | -- arithmetic one). | |
4287 | ||
4288 | In_Membership : constant Boolean := | |
4289 | Nkind (PN) in N_Membership_Test | |
4290 | and then | |
4291 | Nkind (Right_Opnd (PN)) = N_Range | |
4292 | and then | |
4293 | Is_Universal_Numeric_Type (Etype (Left_Opnd (PN))) | |
4294 | and then | |
4295 | Is_Universal_Numeric_Type | |
4296 | (Etype (Low_Bound (Right_Opnd (PN)))) | |
4297 | and then | |
4298 | Is_Universal_Numeric_Type | |
4299 | (Etype (High_Bound (Right_Opnd (PN)))); | |
4300 | -- Case where N is part of a membership test with a universal range | |
4301 | ||
4302 | E : Entity_Id; | |
4303 | Pack : Entity_Id; | |
4304 | Typ1 : Entity_Id := Empty; | |
4305 | Priv_E : Entity_Id; | |
4306 | ||
4307 | function Is_Mixed_Mode_Operand (Op : Node_Id) return Boolean; | |
7ec8363d RD |
4308 | -- Check whether one operand is a mixed-mode operation that requires the |
4309 | -- presence of a fixed-point type. Given that all operands are universal | |
4310 | -- and have been constant-folded, retrieve the original function call. | |
74e7891f RD |
4311 | |
4312 | --------------------------- | |
4313 | -- Is_Mixed_Mode_Operand -- | |
4314 | --------------------------- | |
4315 | ||
4316 | function Is_Mixed_Mode_Operand (Op : Node_Id) return Boolean is | |
7ec8363d | 4317 | Onod : constant Node_Id := Original_Node (Op); |
74e7891f | 4318 | begin |
7ec8363d RD |
4319 | return Nkind (Onod) = N_Function_Call |
4320 | and then Present (Next_Actual (First_Actual (Onod))) | |
4321 | and then Etype (First_Actual (Onod)) /= | |
4322 | Etype (Next_Actual (First_Actual (Onod))); | |
74e7891f RD |
4323 | end Is_Mixed_Mode_Operand; |
4324 | ||
7ec8363d RD |
4325 | -- Start of processing for Find_Universal_Operator_Type |
4326 | ||
74e7891f RD |
4327 | begin |
4328 | if Nkind (Call) /= N_Function_Call | |
4329 | or else Nkind (Name (Call)) /= N_Expanded_Name | |
4330 | then | |
4331 | return Empty; | |
4332 | ||
946db1e2 AC |
4333 | -- There are several cases where the context does not imply the type of |
4334 | -- the operands: | |
4335 | -- - the universal expression appears in a type conversion; | |
4336 | -- - the expression is a relational operator applied to universal | |
4337 | -- operands; | |
4338 | -- - the expression is a membership test with a universal operand | |
4339 | -- and a range with universal bounds. | |
74e7891f RD |
4340 | |
4341 | elsif Nkind (Parent (N)) = N_Type_Conversion | |
7ec8363d RD |
4342 | or else Is_Relational |
4343 | or else In_Membership | |
74e7891f RD |
4344 | then |
4345 | Pack := Entity (Prefix (Name (Call))); | |
4346 | ||
7ec8363d RD |
4347 | -- If the prefix is a package declared elsewhere, iterate over its |
4348 | -- visible entities, otherwise iterate over all declarations in the | |
4349 | -- designated scope. | |
74e7891f RD |
4350 | |
4351 | if Ekind (Pack) = E_Package | |
4352 | and then not In_Open_Scopes (Pack) | |
4353 | then | |
4354 | Priv_E := First_Private_Entity (Pack); | |
4355 | else | |
4356 | Priv_E := Empty; | |
4357 | end if; | |
4358 | ||
4359 | Typ1 := Empty; | |
4360 | E := First_Entity (Pack); | |
4361 | while Present (E) and then E /= Priv_E loop | |
4362 | if Is_Numeric_Type (E) | |
4363 | and then Nkind (Parent (E)) /= N_Subtype_Declaration | |
4364 | and then Comes_From_Source (E) | |
4365 | and then Is_Integer_Type (E) = Is_Int | |
80298c3b AC |
4366 | and then (Nkind (N) in N_Unary_Op |
4367 | or else Is_Relational | |
4368 | or else Is_Fixed_Point_Type (E) = Is_Fix) | |
74e7891f RD |
4369 | then |
4370 | if No (Typ1) then | |
4371 | Typ1 := E; | |
4372 | ||
676e8420 AC |
4373 | -- Before emitting an error, check for the presence of a |
4374 | -- mixed-mode operation that specifies a fixed point type. | |
74e7891f RD |
4375 | |
4376 | elsif Is_Relational | |
4377 | and then | |
4378 | (Is_Mixed_Mode_Operand (Left_Opnd (N)) | |
676e8420 | 4379 | or else Is_Mixed_Mode_Operand (Right_Opnd (N))) |
74e7891f RD |
4380 | and then Is_Fixed_Point_Type (E) /= Is_Fixed_Point_Type (Typ1) |
4381 | ||
4382 | then | |
4383 | if Is_Fixed_Point_Type (E) then | |
4384 | Typ1 := E; | |
4385 | end if; | |
4386 | ||
4387 | else | |
4388 | -- More than one type of the proper class declared in P | |
4389 | ||
4390 | Error_Msg_N ("ambiguous operation", N); | |
4391 | Error_Msg_Sloc := Sloc (Typ1); | |
4392 | Error_Msg_N ("\possible interpretation (inherited)#", N); | |
4393 | Error_Msg_Sloc := Sloc (E); | |
4394 | Error_Msg_N ("\possible interpretation (inherited)#", N); | |
4395 | return Empty; | |
4396 | end if; | |
4397 | end if; | |
4398 | ||
4399 | Next_Entity (E); | |
4400 | end loop; | |
4401 | end if; | |
4402 | ||
4403 | return Typ1; | |
4404 | end Find_Universal_Operator_Type; | |
4405 | ||
fbf5a39b AC |
4406 | -------------------------- |
4407 | -- Flag_Non_Static_Expr -- | |
4408 | -------------------------- | |
4409 | ||
4410 | procedure Flag_Non_Static_Expr (Msg : String; Expr : Node_Id) is | |
4411 | begin | |
4412 | if Error_Posted (Expr) and then not All_Errors_Mode then | |
4413 | return; | |
4414 | else | |
4415 | Error_Msg_F (Msg, Expr); | |
4416 | Why_Not_Static (Expr); | |
4417 | end if; | |
4418 | end Flag_Non_Static_Expr; | |
4419 | ||
996ae0b0 RK |
4420 | -------------- |
4421 | -- Fold_Str -- | |
4422 | -------------- | |
4423 | ||
fbf5a39b | 4424 | procedure Fold_Str (N : Node_Id; Val : String_Id; Static : Boolean) is |
996ae0b0 RK |
4425 | Loc : constant Source_Ptr := Sloc (N); |
4426 | Typ : constant Entity_Id := Etype (N); | |
4427 | ||
4428 | begin | |
edab6088 RD |
4429 | if Raises_Constraint_Error (N) then |
4430 | Set_Is_Static_Expression (N, Static); | |
4431 | return; | |
4432 | end if; | |
4433 | ||
996ae0b0 | 4434 | Rewrite (N, Make_String_Literal (Loc, Strval => Val)); |
fbf5a39b AC |
4435 | |
4436 | -- We now have the literal with the right value, both the actual type | |
4437 | -- and the expected type of this literal are taken from the expression | |
9479ded4 AC |
4438 | -- that was evaluated. So now we do the Analyze and Resolve. |
4439 | ||
4440 | -- Note that we have to reset Is_Static_Expression both after the | |
4441 | -- analyze step (because Resolve will evaluate the literal, which | |
4442 | -- will cause semantic errors if it is marked as static), and after | |
354c3840 | 4443 | -- the Resolve step (since Resolve in some cases resets this flag). |
fbf5a39b AC |
4444 | |
4445 | Analyze (N); | |
4446 | Set_Is_Static_Expression (N, Static); | |
4447 | Set_Etype (N, Typ); | |
4448 | Resolve (N); | |
9479ded4 | 4449 | Set_Is_Static_Expression (N, Static); |
996ae0b0 RK |
4450 | end Fold_Str; |
4451 | ||
4452 | --------------- | |
4453 | -- Fold_Uint -- | |
4454 | --------------- | |
4455 | ||
fbf5a39b | 4456 | procedure Fold_Uint (N : Node_Id; Val : Uint; Static : Boolean) is |
996ae0b0 | 4457 | Loc : constant Source_Ptr := Sloc (N); |
fbf5a39b AC |
4458 | Typ : Entity_Id := Etype (N); |
4459 | Ent : Entity_Id; | |
996ae0b0 RK |
4460 | |
4461 | begin | |
edab6088 RD |
4462 | if Raises_Constraint_Error (N) then |
4463 | Set_Is_Static_Expression (N, Static); | |
4464 | return; | |
4465 | end if; | |
4466 | ||
22cb89b5 AC |
4467 | -- If we are folding a named number, retain the entity in the literal, |
4468 | -- for ASIS use. | |
fbf5a39b | 4469 | |
80298c3b | 4470 | if Is_Entity_Name (N) and then Ekind (Entity (N)) = E_Named_Integer then |
fbf5a39b AC |
4471 | Ent := Entity (N); |
4472 | else | |
4473 | Ent := Empty; | |
4474 | end if; | |
4475 | ||
4476 | if Is_Private_Type (Typ) then | |
4477 | Typ := Full_View (Typ); | |
4478 | end if; | |
4479 | ||
f3d57416 | 4480 | -- For a result of type integer, substitute an N_Integer_Literal node |
996ae0b0 | 4481 | -- for the result of the compile time evaluation of the expression. |
cd2fb920 ES |
4482 | -- For ASIS use, set a link to the original named number when not in |
4483 | -- a generic context. | |
996ae0b0 | 4484 | |
fbf5a39b | 4485 | if Is_Integer_Type (Typ) then |
996ae0b0 | 4486 | Rewrite (N, Make_Integer_Literal (Loc, Val)); |
fbf5a39b | 4487 | Set_Original_Entity (N, Ent); |
996ae0b0 RK |
4488 | |
4489 | -- Otherwise we have an enumeration type, and we substitute either | |
4490 | -- an N_Identifier or N_Character_Literal to represent the enumeration | |
4491 | -- literal corresponding to the given value, which must always be in | |
4492 | -- range, because appropriate tests have already been made for this. | |
4493 | ||
fbf5a39b | 4494 | else pragma Assert (Is_Enumeration_Type (Typ)); |
996ae0b0 RK |
4495 | Rewrite (N, Get_Enum_Lit_From_Pos (Etype (N), Val, Loc)); |
4496 | end if; | |
4497 | ||
4498 | -- We now have the literal with the right value, both the actual type | |
4499 | -- and the expected type of this literal are taken from the expression | |
9479ded4 AC |
4500 | -- that was evaluated. So now we do the Analyze and Resolve. |
4501 | ||
4502 | -- Note that we have to reset Is_Static_Expression both after the | |
4503 | -- analyze step (because Resolve will evaluate the literal, which | |
4504 | -- will cause semantic errors if it is marked as static), and after | |
4505 | -- the Resolve step (since Resolve in some cases sets this flag). | |
996ae0b0 RK |
4506 | |
4507 | Analyze (N); | |
fbf5a39b | 4508 | Set_Is_Static_Expression (N, Static); |
996ae0b0 | 4509 | Set_Etype (N, Typ); |
fbf5a39b | 4510 | Resolve (N); |
9479ded4 | 4511 | Set_Is_Static_Expression (N, Static); |
996ae0b0 RK |
4512 | end Fold_Uint; |
4513 | ||
4514 | ---------------- | |
4515 | -- Fold_Ureal -- | |
4516 | ---------------- | |
4517 | ||
fbf5a39b | 4518 | procedure Fold_Ureal (N : Node_Id; Val : Ureal; Static : Boolean) is |
996ae0b0 RK |
4519 | Loc : constant Source_Ptr := Sloc (N); |
4520 | Typ : constant Entity_Id := Etype (N); | |
fbf5a39b | 4521 | Ent : Entity_Id; |
996ae0b0 RK |
4522 | |
4523 | begin | |
edab6088 RD |
4524 | if Raises_Constraint_Error (N) then |
4525 | Set_Is_Static_Expression (N, Static); | |
4526 | return; | |
4527 | end if; | |
4528 | ||
22cb89b5 AC |
4529 | -- If we are folding a named number, retain the entity in the literal, |
4530 | -- for ASIS use. | |
fbf5a39b | 4531 | |
80298c3b | 4532 | if Is_Entity_Name (N) and then Ekind (Entity (N)) = E_Named_Real then |
fbf5a39b AC |
4533 | Ent := Entity (N); |
4534 | else | |
4535 | Ent := Empty; | |
4536 | end if; | |
4537 | ||
996ae0b0 | 4538 | Rewrite (N, Make_Real_Literal (Loc, Realval => Val)); |
cd2fb920 | 4539 | |
5a30024a | 4540 | -- Set link to original named number, for ASIS use |
cd2fb920 | 4541 | |
fbf5a39b | 4542 | Set_Original_Entity (N, Ent); |
996ae0b0 | 4543 | |
9479ded4 AC |
4544 | -- We now have the literal with the right value, both the actual type |
4545 | -- and the expected type of this literal are taken from the expression | |
4546 | -- that was evaluated. So now we do the Analyze and Resolve. | |
4547 | ||
4548 | -- Note that we have to reset Is_Static_Expression both after the | |
4549 | -- analyze step (because Resolve will evaluate the literal, which | |
4550 | -- will cause semantic errors if it is marked as static), and after | |
4551 | -- the Resolve step (since Resolve in some cases sets this flag). | |
996ae0b0 | 4552 | |
fbf5a39b AC |
4553 | Analyze (N); |
4554 | Set_Is_Static_Expression (N, Static); | |
996ae0b0 | 4555 | Set_Etype (N, Typ); |
fbf5a39b | 4556 | Resolve (N); |
9479ded4 | 4557 | Set_Is_Static_Expression (N, Static); |
996ae0b0 RK |
4558 | end Fold_Ureal; |
4559 | ||
4560 | --------------- | |
4561 | -- From_Bits -- | |
4562 | --------------- | |
4563 | ||
4564 | function From_Bits (B : Bits; T : Entity_Id) return Uint is | |
4565 | V : Uint := Uint_0; | |
4566 | ||
4567 | begin | |
4568 | for J in 0 .. B'Last loop | |
4569 | if B (J) then | |
4570 | V := V + 2 ** J; | |
4571 | end if; | |
4572 | end loop; | |
4573 | ||
4574 | if Non_Binary_Modulus (T) then | |
4575 | V := V mod Modulus (T); | |
4576 | end if; | |
4577 | ||
4578 | return V; | |
4579 | end From_Bits; | |
4580 | ||
4581 | -------------------- | |
4582 | -- Get_String_Val -- | |
4583 | -------------------- | |
4584 | ||
4585 | function Get_String_Val (N : Node_Id) return Node_Id is | |
4586 | begin | |
80298c3b | 4587 | if Nkind_In (N, N_String_Literal, N_Character_Literal) then |
996ae0b0 | 4588 | return N; |
996ae0b0 RK |
4589 | else |
4590 | pragma Assert (Is_Entity_Name (N)); | |
4591 | return Get_String_Val (Constant_Value (Entity (N))); | |
4592 | end if; | |
4593 | end Get_String_Val; | |
4594 | ||
fbf5a39b AC |
4595 | ---------------- |
4596 | -- Initialize -- | |
4597 | ---------------- | |
4598 | ||
4599 | procedure Initialize is | |
4600 | begin | |
4601 | CV_Cache := (others => (Node_High_Bound, Uint_0)); | |
4602 | end Initialize; | |
4603 | ||
996ae0b0 RK |
4604 | -------------------- |
4605 | -- In_Subrange_Of -- | |
4606 | -------------------- | |
4607 | ||
4608 | function In_Subrange_Of | |
c27f2f15 RD |
4609 | (T1 : Entity_Id; |
4610 | T2 : Entity_Id; | |
4611 | Fixed_Int : Boolean := False) return Boolean | |
996ae0b0 RK |
4612 | is |
4613 | L1 : Node_Id; | |
4614 | H1 : Node_Id; | |
4615 | ||
4616 | L2 : Node_Id; | |
4617 | H2 : Node_Id; | |
4618 | ||
4619 | begin | |
4620 | if T1 = T2 or else Is_Subtype_Of (T1, T2) then | |
4621 | return True; | |
4622 | ||
4623 | -- Never in range if both types are not scalar. Don't know if this can | |
4624 | -- actually happen, but just in case. | |
4625 | ||
9d08a38d | 4626 | elsif not Is_Scalar_Type (T1) or else not Is_Scalar_Type (T2) then |
996ae0b0 RK |
4627 | return False; |
4628 | ||
d79e621a GD |
4629 | -- If T1 has infinities but T2 doesn't have infinities, then T1 is |
4630 | -- definitely not compatible with T2. | |
4631 | ||
4632 | elsif Is_Floating_Point_Type (T1) | |
4633 | and then Has_Infinities (T1) | |
4634 | and then Is_Floating_Point_Type (T2) | |
4635 | and then not Has_Infinities (T2) | |
4636 | then | |
4637 | return False; | |
4638 | ||
996ae0b0 RK |
4639 | else |
4640 | L1 := Type_Low_Bound (T1); | |
4641 | H1 := Type_High_Bound (T1); | |
4642 | ||
4643 | L2 := Type_Low_Bound (T2); | |
4644 | H2 := Type_High_Bound (T2); | |
4645 | ||
4646 | -- Check bounds to see if comparison possible at compile time | |
4647 | ||
c27f2f15 | 4648 | if Compile_Time_Compare (L1, L2, Assume_Valid => True) in Compare_GE |
996ae0b0 | 4649 | and then |
c27f2f15 | 4650 | Compile_Time_Compare (H1, H2, Assume_Valid => True) in Compare_LE |
996ae0b0 RK |
4651 | then |
4652 | return True; | |
4653 | end if; | |
4654 | ||
4655 | -- If bounds not comparable at compile time, then the bounds of T2 | |
4656 | -- must be compile time known or we cannot answer the query. | |
4657 | ||
4658 | if not Compile_Time_Known_Value (L2) | |
4659 | or else not Compile_Time_Known_Value (H2) | |
4660 | then | |
4661 | return False; | |
4662 | end if; | |
4663 | ||
4664 | -- If the bounds of T1 are know at compile time then use these | |
4665 | -- ones, otherwise use the bounds of the base type (which are of | |
4666 | -- course always static). | |
4667 | ||
4668 | if not Compile_Time_Known_Value (L1) then | |
4669 | L1 := Type_Low_Bound (Base_Type (T1)); | |
4670 | end if; | |
4671 | ||
4672 | if not Compile_Time_Known_Value (H1) then | |
4673 | H1 := Type_High_Bound (Base_Type (T1)); | |
4674 | end if; | |
4675 | ||
4676 | -- Fixed point types should be considered as such only if | |
4677 | -- flag Fixed_Int is set to False. | |
4678 | ||
4679 | if Is_Floating_Point_Type (T1) or else Is_Floating_Point_Type (T2) | |
4680 | or else (Is_Fixed_Point_Type (T1) and then not Fixed_Int) | |
4681 | or else (Is_Fixed_Point_Type (T2) and then not Fixed_Int) | |
4682 | then | |
4683 | return | |
4684 | Expr_Value_R (L2) <= Expr_Value_R (L1) | |
4685 | and then | |
4686 | Expr_Value_R (H2) >= Expr_Value_R (H1); | |
4687 | ||
4688 | else | |
4689 | return | |
4690 | Expr_Value (L2) <= Expr_Value (L1) | |
4691 | and then | |
4692 | Expr_Value (H2) >= Expr_Value (H1); | |
4693 | ||
4694 | end if; | |
4695 | end if; | |
4696 | ||
4697 | -- If any exception occurs, it means that we have some bug in the compiler | |
f3d57416 | 4698 | -- possibly triggered by a previous error, or by some unforeseen peculiar |
996ae0b0 RK |
4699 | -- occurrence. However, this is only an optimization attempt, so there is |
4700 | -- really no point in crashing the compiler. Instead we just decide, too | |
4701 | -- bad, we can't figure out the answer in this case after all. | |
4702 | ||
4703 | exception | |
4704 | when others => | |
4705 | ||
4706 | -- Debug flag K disables this behavior (useful for debugging) | |
4707 | ||
4708 | if Debug_Flag_K then | |
4709 | raise; | |
4710 | else | |
4711 | return False; | |
4712 | end if; | |
4713 | end In_Subrange_Of; | |
4714 | ||
4715 | ----------------- | |
4716 | -- Is_In_Range -- | |
4717 | ----------------- | |
4718 | ||
4719 | function Is_In_Range | |
c800f862 RD |
4720 | (N : Node_Id; |
4721 | Typ : Entity_Id; | |
4722 | Assume_Valid : Boolean := False; | |
4723 | Fixed_Int : Boolean := False; | |
4724 | Int_Real : Boolean := False) return Boolean | |
996ae0b0 | 4725 | is |
996ae0b0 | 4726 | begin |
80298c3b AC |
4727 | return |
4728 | Test_In_Range (N, Typ, Assume_Valid, Fixed_Int, Int_Real) = In_Range; | |
996ae0b0 RK |
4729 | end Is_In_Range; |
4730 | ||
4731 | ------------------- | |
4732 | -- Is_Null_Range -- | |
4733 | ------------------- | |
4734 | ||
4735 | function Is_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is | |
4736 | Typ : constant Entity_Id := Etype (Lo); | |
4737 | ||
4738 | begin | |
4739 | if not Compile_Time_Known_Value (Lo) | |
4740 | or else not Compile_Time_Known_Value (Hi) | |
4741 | then | |
4742 | return False; | |
4743 | end if; | |
4744 | ||
4745 | if Is_Discrete_Type (Typ) then | |
4746 | return Expr_Value (Lo) > Expr_Value (Hi); | |
80298c3b | 4747 | else pragma Assert (Is_Real_Type (Typ)); |
996ae0b0 RK |
4748 | return Expr_Value_R (Lo) > Expr_Value_R (Hi); |
4749 | end if; | |
4750 | end Is_Null_Range; | |
4751 | ||
edab6088 RD |
4752 | ------------------------- |
4753 | -- Is_OK_Static_Choice -- | |
4754 | ------------------------- | |
4755 | ||
4756 | function Is_OK_Static_Choice (Choice : Node_Id) return Boolean is | |
4757 | begin | |
4758 | -- Check various possibilities for choice | |
4759 | ||
4760 | -- Note: for membership tests, we test more cases than are possible | |
4761 | -- (in particular subtype indication), but it doesn't matter because | |
4762 | -- it just won't occur (we have already done a syntax check). | |
4763 | ||
4764 | if Nkind (Choice) = N_Others_Choice then | |
4765 | return True; | |
4766 | ||
4767 | elsif Nkind (Choice) = N_Range then | |
4768 | return Is_OK_Static_Range (Choice); | |
4769 | ||
4770 | elsif Nkind (Choice) = N_Subtype_Indication | |
87feba05 | 4771 | or else (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice))) |
edab6088 RD |
4772 | then |
4773 | return Is_OK_Static_Subtype (Etype (Choice)); | |
4774 | ||
4775 | else | |
4776 | return Is_OK_Static_Expression (Choice); | |
4777 | end if; | |
4778 | end Is_OK_Static_Choice; | |
4779 | ||
4780 | ------------------------------ | |
4781 | -- Is_OK_Static_Choice_List -- | |
4782 | ------------------------------ | |
4783 | ||
4784 | function Is_OK_Static_Choice_List (Choices : List_Id) return Boolean is | |
4785 | Choice : Node_Id; | |
4786 | ||
4787 | begin | |
4788 | if not Is_Static_Choice_List (Choices) then | |
4789 | return False; | |
4790 | end if; | |
4791 | ||
4792 | Choice := First (Choices); | |
4793 | while Present (Choice) loop | |
4794 | if not Is_OK_Static_Choice (Choice) then | |
4795 | Set_Raises_Constraint_Error (Choice); | |
4796 | return False; | |
4797 | end if; | |
4798 | ||
4799 | Next (Choice); | |
4800 | end loop; | |
4801 | ||
4802 | return True; | |
4803 | end Is_OK_Static_Choice_List; | |
4804 | ||
996ae0b0 RK |
4805 | ----------------------------- |
4806 | -- Is_OK_Static_Expression -- | |
4807 | ----------------------------- | |
4808 | ||
4809 | function Is_OK_Static_Expression (N : Node_Id) return Boolean is | |
4810 | begin | |
80298c3b | 4811 | return Is_Static_Expression (N) and then not Raises_Constraint_Error (N); |
996ae0b0 RK |
4812 | end Is_OK_Static_Expression; |
4813 | ||
4814 | ------------------------ | |
4815 | -- Is_OK_Static_Range -- | |
4816 | ------------------------ | |
4817 | ||
4818 | -- A static range is a range whose bounds are static expressions, or a | |
4819 | -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)). | |
4820 | -- We have already converted range attribute references, so we get the | |
4821 | -- "or" part of this rule without needing a special test. | |
4822 | ||
4823 | function Is_OK_Static_Range (N : Node_Id) return Boolean is | |
4824 | begin | |
4825 | return Is_OK_Static_Expression (Low_Bound (N)) | |
4826 | and then Is_OK_Static_Expression (High_Bound (N)); | |
4827 | end Is_OK_Static_Range; | |
4828 | ||
4829 | -------------------------- | |
4830 | -- Is_OK_Static_Subtype -- | |
4831 | -------------------------- | |
4832 | ||
22cb89b5 AC |
4833 | -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) where |
4834 | -- neither bound raises constraint error when evaluated. | |
996ae0b0 RK |
4835 | |
4836 | function Is_OK_Static_Subtype (Typ : Entity_Id) return Boolean is | |
4837 | Base_T : constant Entity_Id := Base_Type (Typ); | |
4838 | Anc_Subt : Entity_Id; | |
4839 | ||
4840 | begin | |
4841 | -- First a quick check on the non static subtype flag. As described | |
4842 | -- in further detail in Einfo, this flag is not decisive in all cases, | |
4843 | -- but if it is set, then the subtype is definitely non-static. | |
4844 | ||
4845 | if Is_Non_Static_Subtype (Typ) then | |
4846 | return False; | |
4847 | end if; | |
4848 | ||
4849 | Anc_Subt := Ancestor_Subtype (Typ); | |
4850 | ||
4851 | if Anc_Subt = Empty then | |
4852 | Anc_Subt := Base_T; | |
4853 | end if; | |
4854 | ||
4855 | if Is_Generic_Type (Root_Type (Base_T)) | |
4856 | or else Is_Generic_Actual_Type (Base_T) | |
4857 | then | |
4858 | return False; | |
4859 | ||
87feba05 AC |
4860 | elsif Has_Dynamic_Predicate_Aspect (Typ) then |
4861 | return False; | |
4862 | ||
996ae0b0 RK |
4863 | -- String types |
4864 | ||
4865 | elsif Is_String_Type (Typ) then | |
4866 | return | |
4867 | Ekind (Typ) = E_String_Literal_Subtype | |
4868 | or else | |
011f9d5d AC |
4869 | (Is_OK_Static_Subtype (Component_Type (Typ)) |
4870 | and then Is_OK_Static_Subtype (Etype (First_Index (Typ)))); | |
996ae0b0 RK |
4871 | |
4872 | -- Scalar types | |
4873 | ||
4874 | elsif Is_Scalar_Type (Typ) then | |
4875 | if Base_T = Typ then | |
4876 | return True; | |
4877 | ||
4878 | else | |
22cb89b5 AC |
4879 | -- Scalar_Range (Typ) might be an N_Subtype_Indication, so use |
4880 | -- Get_Type_{Low,High}_Bound. | |
996ae0b0 RK |
4881 | |
4882 | return Is_OK_Static_Subtype (Anc_Subt) | |
4883 | and then Is_OK_Static_Expression (Type_Low_Bound (Typ)) | |
4884 | and then Is_OK_Static_Expression (Type_High_Bound (Typ)); | |
4885 | end if; | |
4886 | ||
4887 | -- Types other than string and scalar types are never static | |
4888 | ||
4889 | else | |
4890 | return False; | |
4891 | end if; | |
4892 | end Is_OK_Static_Subtype; | |
4893 | ||
4894 | --------------------- | |
4895 | -- Is_Out_Of_Range -- | |
4896 | --------------------- | |
4897 | ||
4898 | function Is_Out_Of_Range | |
1c7717c3 AC |
4899 | (N : Node_Id; |
4900 | Typ : Entity_Id; | |
c800f862 | 4901 | Assume_Valid : Boolean := False; |
1c7717c3 AC |
4902 | Fixed_Int : Boolean := False; |
4903 | Int_Real : Boolean := False) return Boolean | |
996ae0b0 | 4904 | is |
996ae0b0 | 4905 | begin |
80298c3b AC |
4906 | return Test_In_Range (N, Typ, Assume_Valid, Fixed_Int, Int_Real) = |
4907 | Out_Of_Range; | |
996ae0b0 RK |
4908 | end Is_Out_Of_Range; |
4909 | ||
edab6088 RD |
4910 | ---------------------- |
4911 | -- Is_Static_Choice -- | |
4912 | ---------------------- | |
4913 | ||
4914 | function Is_Static_Choice (Choice : Node_Id) return Boolean is | |
4915 | begin | |
4916 | -- Check various possibilities for choice | |
4917 | ||
4918 | -- Note: for membership tests, we test more cases than are possible | |
4919 | -- (in particular subtype indication), but it doesn't matter because | |
4920 | -- it just won't occur (we have already done a syntax check). | |
4921 | ||
4922 | if Nkind (Choice) = N_Others_Choice then | |
4923 | return True; | |
4924 | ||
4925 | elsif Nkind (Choice) = N_Range then | |
4926 | return Is_Static_Range (Choice); | |
4927 | ||
4928 | elsif Nkind (Choice) = N_Subtype_Indication | |
87feba05 | 4929 | or else (Is_Entity_Name (Choice) and then Is_Type (Entity (Choice))) |
edab6088 RD |
4930 | then |
4931 | return Is_Static_Subtype (Etype (Choice)); | |
4932 | ||
4933 | else | |
4934 | return Is_Static_Expression (Choice); | |
4935 | end if; | |
4936 | end Is_Static_Choice; | |
4937 | ||
4938 | --------------------------- | |
4939 | -- Is_Static_Choice_List -- | |
4940 | --------------------------- | |
4941 | ||
4942 | function Is_Static_Choice_List (Choices : List_Id) return Boolean is | |
4943 | Choice : Node_Id; | |
4944 | ||
4945 | begin | |
4946 | Choice := First (Choices); | |
4947 | while Present (Choice) loop | |
4948 | if not Is_Static_Choice (Choice) then | |
4949 | return False; | |
4950 | end if; | |
4951 | ||
4952 | Next (Choice); | |
4953 | end loop; | |
4954 | ||
4955 | return True; | |
4956 | end Is_Static_Choice_List; | |
4957 | ||
87feba05 | 4958 | --------------------- |
996ae0b0 RK |
4959 | -- Is_Static_Range -- |
4960 | --------------------- | |
4961 | ||
4962 | -- A static range is a range whose bounds are static expressions, or a | |
4963 | -- Range_Attribute_Reference equivalent to such a range (RM 4.9(26)). | |
4964 | -- We have already converted range attribute references, so we get the | |
4965 | -- "or" part of this rule without needing a special test. | |
4966 | ||
4967 | function Is_Static_Range (N : Node_Id) return Boolean is | |
4968 | begin | |
edab6088 | 4969 | return Is_Static_Expression (Low_Bound (N)) |
80298c3b AC |
4970 | and then |
4971 | Is_Static_Expression (High_Bound (N)); | |
996ae0b0 RK |
4972 | end Is_Static_Range; |
4973 | ||
4974 | ----------------------- | |
4975 | -- Is_Static_Subtype -- | |
4976 | ----------------------- | |
4977 | ||
82c80734 | 4978 | -- Determines if Typ is a static subtype as defined in (RM 4.9(26)) |
996ae0b0 RK |
4979 | |
4980 | function Is_Static_Subtype (Typ : Entity_Id) return Boolean is | |
4981 | Base_T : constant Entity_Id := Base_Type (Typ); | |
4982 | Anc_Subt : Entity_Id; | |
4983 | ||
4984 | begin | |
4985 | -- First a quick check on the non static subtype flag. As described | |
4986 | -- in further detail in Einfo, this flag is not decisive in all cases, | |
4987 | -- but if it is set, then the subtype is definitely non-static. | |
4988 | ||
4989 | if Is_Non_Static_Subtype (Typ) then | |
4990 | return False; | |
4991 | end if; | |
4992 | ||
4993 | Anc_Subt := Ancestor_Subtype (Typ); | |
4994 | ||
4995 | if Anc_Subt = Empty then | |
4996 | Anc_Subt := Base_T; | |
4997 | end if; | |
4998 | ||
4999 | if Is_Generic_Type (Root_Type (Base_T)) | |
5000 | or else Is_Generic_Actual_Type (Base_T) | |
5001 | then | |
5002 | return False; | |
5003 | ||
ca0eb951 AC |
5004 | -- If there is a dynamic predicate for the type (declared or inherited) |
5005 | -- the expression is not static. | |
5006 | ||
5007 | elsif Has_Dynamic_Predicate_Aspect (Typ) | |
5008 | or else (Is_Derived_Type (Typ) | |
5009 | and then Has_Aspect (Typ, Aspect_Dynamic_Predicate)) | |
5010 | then | |
87feba05 AC |
5011 | return False; |
5012 | ||
996ae0b0 RK |
5013 | -- String types |
5014 | ||
5015 | elsif Is_String_Type (Typ) then | |
5016 | return | |
5017 | Ekind (Typ) = E_String_Literal_Subtype | |
011f9d5d AC |
5018 | or else (Is_Static_Subtype (Component_Type (Typ)) |
5019 | and then Is_Static_Subtype (Etype (First_Index (Typ)))); | |
996ae0b0 RK |
5020 | |
5021 | -- Scalar types | |
5022 | ||
5023 | elsif Is_Scalar_Type (Typ) then | |
5024 | if Base_T = Typ then | |
5025 | return True; | |
5026 | ||
5027 | else | |
5028 | return Is_Static_Subtype (Anc_Subt) | |
5029 | and then Is_Static_Expression (Type_Low_Bound (Typ)) | |
5030 | and then Is_Static_Expression (Type_High_Bound (Typ)); | |
5031 | end if; | |
5032 | ||
5033 | -- Types other than string and scalar types are never static | |
5034 | ||
5035 | else | |
5036 | return False; | |
5037 | end if; | |
5038 | end Is_Static_Subtype; | |
5039 | ||
edab6088 RD |
5040 | ------------------------------- |
5041 | -- Is_Statically_Unevaluated -- | |
5042 | ------------------------------- | |
5043 | ||
5044 | function Is_Statically_Unevaluated (Expr : Node_Id) return Boolean is | |
5045 | function Check_Case_Expr_Alternative | |
5046 | (CEA : Node_Id) return Match_Result; | |
5047 | -- We have a message emanating from the Expression of a case expression | |
5048 | -- alternative. We examine this alternative, as follows: | |
5049 | -- | |
5050 | -- If the selecting expression of the parent case is non-static, or | |
5051 | -- if any of the discrete choices of the given case alternative are | |
5052 | -- non-static or raise Constraint_Error, return Non_Static. | |
5053 | -- | |
5054 | -- Otherwise check if the selecting expression matches any of the given | |
4bd4bb7f AC |
5055 | -- discrete choices. If so, the alternative is executed and we return |
5056 | -- Match, otherwise, the alternative can never be executed, and so we | |
5057 | -- return No_Match. | |
edab6088 RD |
5058 | |
5059 | --------------------------------- | |
5060 | -- Check_Case_Expr_Alternative -- | |
5061 | --------------------------------- | |
5062 | ||
5063 | function Check_Case_Expr_Alternative | |
5064 | (CEA : Node_Id) return Match_Result | |
5065 | is | |
5066 | Case_Exp : constant Node_Id := Parent (CEA); | |
5067 | Choice : Node_Id; | |
5068 | Prev_CEA : Node_Id; | |
5069 | ||
5070 | begin | |
5071 | pragma Assert (Nkind (Case_Exp) = N_Case_Expression); | |
5072 | ||
4bd4bb7f | 5073 | -- Check that selecting expression is static |
edab6088 RD |
5074 | |
5075 | if not Is_OK_Static_Expression (Expression (Case_Exp)) then | |
5076 | return Non_Static; | |
5077 | end if; | |
5078 | ||
5079 | if not Is_OK_Static_Choice_List (Discrete_Choices (CEA)) then | |
5080 | return Non_Static; | |
5081 | end if; | |
5082 | ||
5083 | -- All choices are now known to be static. Now see if alternative | |
5084 | -- matches one of the choices. | |
5085 | ||
5086 | Choice := First (Discrete_Choices (CEA)); | |
5087 | while Present (Choice) loop | |
5088 | ||
4bd4bb7f | 5089 | -- Check various possibilities for choice, returning Match if we |
edab6088 RD |
5090 | -- find the selecting value matches any of the choices. Note that |
5091 | -- we know we are the last choice, so we don't have to keep going. | |
5092 | ||
5093 | if Nkind (Choice) = N_Others_Choice then | |
5094 | ||
5095 | -- Others choice is a bit annoying, it matches if none of the | |
5096 | -- previous alternatives matches (note that we know we are the | |
5097 | -- last alternative in this case, so we can just go backwards | |
5098 | -- from us to see if any previous one matches). | |
5099 | ||
5100 | Prev_CEA := Prev (CEA); | |
5101 | while Present (Prev_CEA) loop | |
5102 | if Check_Case_Expr_Alternative (Prev_CEA) = Match then | |
5103 | return No_Match; | |
5104 | end if; | |
5105 | ||
5106 | Prev (Prev_CEA); | |
5107 | end loop; | |
5108 | ||
5109 | return Match; | |
5110 | ||
5111 | -- Else we have a normal static choice | |
5112 | ||
5113 | elsif Choice_Matches (Expression (Case_Exp), Choice) = Match then | |
5114 | return Match; | |
5115 | end if; | |
5116 | ||
5117 | -- If we fall through, it means that the discrete choice did not | |
5118 | -- match the selecting expression, so continue. | |
5119 | ||
5120 | Next (Choice); | |
5121 | end loop; | |
5122 | ||
4bd4bb7f AC |
5123 | -- If we get through that loop then all choices were static, and none |
5124 | -- of them matched the selecting expression. So return No_Match. | |
edab6088 RD |
5125 | |
5126 | return No_Match; | |
5127 | end Check_Case_Expr_Alternative; | |
5128 | ||
5129 | -- Local variables | |
5130 | ||
5131 | P : Node_Id; | |
5132 | OldP : Node_Id; | |
5133 | Choice : Node_Id; | |
5134 | ||
5135 | -- Start of processing for Is_Statically_Unevaluated | |
5136 | ||
5137 | begin | |
5138 | -- The (32.x) references here are from RM section 4.9 | |
5139 | ||
5140 | -- (32.1) An expression is statically unevaluated if it is part of ... | |
5141 | ||
5142 | -- This means we have to climb the tree looking for one of the cases | |
5143 | ||
5144 | P := Expr; | |
5145 | loop | |
5146 | OldP := P; | |
5147 | P := Parent (P); | |
5148 | ||
5149 | -- (32.2) The right operand of a static short-circuit control form | |
5150 | -- whose value is determined by its left operand. | |
5151 | ||
5152 | -- AND THEN with False as left operand | |
5153 | ||
5154 | if Nkind (P) = N_And_Then | |
5155 | and then Compile_Time_Known_Value (Left_Opnd (P)) | |
5156 | and then Is_False (Expr_Value (Left_Opnd (P))) | |
5157 | then | |
5158 | return True; | |
5159 | ||
5160 | -- OR ELSE with True as left operand | |
5161 | ||
5162 | elsif Nkind (P) = N_Or_Else | |
5163 | and then Compile_Time_Known_Value (Left_Opnd (P)) | |
5164 | and then Is_True (Expr_Value (Left_Opnd (P))) | |
5165 | then | |
5166 | return True; | |
5167 | ||
5168 | -- (32.3) A dependent_expression of an if_expression whose associated | |
5169 | -- condition is static and equals False. | |
5170 | ||
5171 | elsif Nkind (P) = N_If_Expression then | |
5172 | declare | |
5173 | Cond : constant Node_Id := First (Expressions (P)); | |
5174 | Texp : constant Node_Id := Next (Cond); | |
5175 | Fexp : constant Node_Id := Next (Texp); | |
5176 | ||
5177 | begin | |
5178 | if Compile_Time_Known_Value (Cond) then | |
5179 | ||
5180 | -- Condition is True and we are in the right operand | |
5181 | ||
5182 | if Is_True (Expr_Value (Cond)) and then OldP = Fexp then | |
5183 | return True; | |
5184 | ||
5185 | -- Condition is False and we are in the left operand | |
5186 | ||
5187 | elsif Is_False (Expr_Value (Cond)) and then OldP = Texp then | |
5188 | return True; | |
5189 | end if; | |
5190 | end if; | |
5191 | end; | |
5192 | ||
5193 | -- (32.4) A condition or dependent_expression of an if_expression | |
5194 | -- where the condition corresponding to at least one preceding | |
5195 | -- dependent_expression of the if_expression is static and equals | |
5196 | -- True. | |
5197 | ||
5198 | -- This refers to cases like | |
5199 | ||
4bd4bb7f | 5200 | -- (if True then 1 elsif 1/0=2 then 2 else 3) |
edab6088 RD |
5201 | |
5202 | -- But we expand elsif's out anyway, so the above looks like: | |
5203 | ||
4bd4bb7f | 5204 | -- (if True then 1 else (if 1/0=2 then 2 else 3)) |
edab6088 RD |
5205 | |
5206 | -- So for us this is caught by the above check for the 32.3 case. | |
5207 | ||
5208 | -- (32.5) A dependent_expression of a case_expression whose | |
5209 | -- selecting_expression is static and whose value is not covered | |
5210 | -- by the corresponding discrete_choice_list. | |
5211 | ||
5212 | elsif Nkind (P) = N_Case_Expression_Alternative then | |
5213 | ||
5214 | -- First, we have to be in the expression to suppress messages. | |
5215 | -- If we are within one of the choices, we want the message. | |
5216 | ||
5217 | if OldP = Expression (P) then | |
5218 | ||
5219 | -- Statically unevaluated if alternative does not match | |
5220 | ||
5221 | if Check_Case_Expr_Alternative (P) = No_Match then | |
5222 | return True; | |
5223 | end if; | |
5224 | end if; | |
5225 | ||
5226 | -- (32.6) A choice_expression (or a simple_expression of a range | |
5227 | -- that occurs as a membership_choice of a membership_choice_list) | |
5228 | -- of a static membership test that is preceded in the enclosing | |
5229 | -- membership_choice_list by another item whose individual | |
5230 | -- membership test (see (RM 4.5.2)) statically yields True. | |
5231 | ||
5232 | elsif Nkind (P) in N_Membership_Test then | |
5233 | ||
5234 | -- Only possibly unevaluated if simple expression is static | |
5235 | ||
5236 | if not Is_OK_Static_Expression (Left_Opnd (P)) then | |
5237 | null; | |
5238 | ||
5239 | -- All members of the choice list must be static | |
5240 | ||
5241 | elsif (Present (Right_Opnd (P)) | |
5242 | and then not Is_OK_Static_Choice (Right_Opnd (P))) | |
5243 | or else (Present (Alternatives (P)) | |
5244 | and then | |
5245 | not Is_OK_Static_Choice_List (Alternatives (P))) | |
5246 | then | |
5247 | null; | |
5248 | ||
5249 | -- If expression is the one and only alternative, then it is | |
5250 | -- definitely not statically unevaluated, so we only have to | |
5251 | -- test the case where there are alternatives present. | |
5252 | ||
5253 | elsif Present (Alternatives (P)) then | |
5254 | ||
5255 | -- Look for previous matching Choice | |
5256 | ||
5257 | Choice := First (Alternatives (P)); | |
5258 | while Present (Choice) loop | |
5259 | ||
5260 | -- If we reached us and no previous choices matched, this | |
5261 | -- is not the case where we are statically unevaluated. | |
5262 | ||
5263 | exit when OldP = Choice; | |
5264 | ||
5265 | -- If a previous choice matches, then that is the case where | |
5266 | -- we know our choice is statically unevaluated. | |
5267 | ||
5268 | if Choice_Matches (Left_Opnd (P), Choice) = Match then | |
5269 | return True; | |
5270 | end if; | |
5271 | ||
5272 | Next (Choice); | |
5273 | end loop; | |
5274 | ||
5275 | -- If we fall through the loop, we were not one of the choices, | |
5276 | -- we must have been the expression, so that is not covered by | |
5277 | -- this rule, and we keep going. | |
5278 | ||
5279 | null; | |
5280 | end if; | |
5281 | end if; | |
5282 | ||
5283 | -- OK, not statically unevaluated at this level, see if we should | |
5284 | -- keep climbing to look for a higher level reason. | |
5285 | ||
5286 | -- Special case for component association in aggregates, where | |
5287 | -- we want to keep climbing up to the parent aggregate. | |
5288 | ||
5289 | if Nkind (P) = N_Component_Association | |
5290 | and then Nkind (Parent (P)) = N_Aggregate | |
5291 | then | |
5292 | null; | |
5293 | ||
5294 | -- All done if not still within subexpression | |
5295 | ||
5296 | else | |
5297 | exit when Nkind (P) not in N_Subexpr; | |
5298 | end if; | |
5299 | end loop; | |
5300 | ||
5301 | -- If we fall through the loop, not one of the cases covered! | |
5302 | ||
5303 | return False; | |
5304 | end Is_Statically_Unevaluated; | |
5305 | ||
996ae0b0 RK |
5306 | -------------------- |
5307 | -- Not_Null_Range -- | |
5308 | -------------------- | |
5309 | ||
5310 | function Not_Null_Range (Lo : Node_Id; Hi : Node_Id) return Boolean is | |
5311 | Typ : constant Entity_Id := Etype (Lo); | |
5312 | ||
5313 | begin | |
5314 | if not Compile_Time_Known_Value (Lo) | |
5315 | or else not Compile_Time_Known_Value (Hi) | |
5316 | then | |
5317 | return False; | |
5318 | end if; | |
5319 | ||
5320 | if Is_Discrete_Type (Typ) then | |
5321 | return Expr_Value (Lo) <= Expr_Value (Hi); | |
80298c3b | 5322 | else pragma Assert (Is_Real_Type (Typ)); |
996ae0b0 RK |
5323 | return Expr_Value_R (Lo) <= Expr_Value_R (Hi); |
5324 | end if; | |
5325 | end Not_Null_Range; | |
5326 | ||
5327 | ------------- | |
5328 | -- OK_Bits -- | |
5329 | ------------- | |
5330 | ||
5331 | function OK_Bits (N : Node_Id; Bits : Uint) return Boolean is | |
5332 | begin | |
5333 | -- We allow a maximum of 500,000 bits which seems a reasonable limit | |
5334 | ||
5335 | if Bits < 500_000 then | |
5336 | return True; | |
5337 | ||
80298c3b AC |
5338 | -- Error if this maximum is exceeded |
5339 | ||
996ae0b0 RK |
5340 | else |
5341 | Error_Msg_N ("static value too large, capacity exceeded", N); | |
5342 | return False; | |
5343 | end if; | |
5344 | end OK_Bits; | |
5345 | ||
5346 | ------------------ | |
5347 | -- Out_Of_Range -- | |
5348 | ------------------ | |
5349 | ||
5350 | procedure Out_Of_Range (N : Node_Id) is | |
5351 | begin | |
5352 | -- If we have the static expression case, then this is an illegality | |
5353 | -- in Ada 95 mode, except that in an instance, we never generate an | |
22cb89b5 | 5354 | -- error (if the error is legitimate, it was already diagnosed in the |
ac072cb2 | 5355 | -- template). |
996ae0b0 RK |
5356 | |
5357 | if Is_Static_Expression (N) | |
5358 | and then not In_Instance | |
fbf5a39b | 5359 | and then not In_Inlined_Body |
0ab80019 | 5360 | and then Ada_Version >= Ada_95 |
996ae0b0 | 5361 | then |
4bd4bb7f | 5362 | -- No message if we are statically unevaluated |
ac072cb2 AC |
5363 | |
5364 | if Is_Statically_Unevaluated (N) then | |
5365 | null; | |
5366 | ||
5367 | -- The expression to compute the length of a packed array is attached | |
5368 | -- to the array type itself, and deserves a separate message. | |
5369 | ||
5370 | elsif Nkind (Parent (N)) = N_Defining_Identifier | |
996ae0b0 | 5371 | and then Is_Array_Type (Parent (N)) |
8ca597af | 5372 | and then Present (Packed_Array_Impl_Type (Parent (N))) |
996ae0b0 RK |
5373 | and then Present (First_Rep_Item (Parent (N))) |
5374 | then | |
5375 | Error_Msg_N | |
5376 | ("length of packed array must not exceed Integer''Last", | |
5377 | First_Rep_Item (Parent (N))); | |
5378 | Rewrite (N, Make_Integer_Literal (Sloc (N), Uint_1)); | |
5379 | ||
ac072cb2 AC |
5380 | -- All cases except the special array case |
5381 | ||
996ae0b0 RK |
5382 | else |
5383 | Apply_Compile_Time_Constraint_Error | |
07fc65c4 | 5384 | (N, "value not in range of}", CE_Range_Check_Failed); |
996ae0b0 RK |
5385 | end if; |
5386 | ||
22cb89b5 AC |
5387 | -- Here we generate a warning for the Ada 83 case, or when we are in an |
5388 | -- instance, or when we have a non-static expression case. | |
996ae0b0 RK |
5389 | |
5390 | else | |
996ae0b0 | 5391 | Apply_Compile_Time_Constraint_Error |
324ac540 | 5392 | (N, "value not in range of}??", CE_Range_Check_Failed); |
996ae0b0 RK |
5393 | end if; |
5394 | end Out_Of_Range; | |
5395 | ||
7f568bfa AC |
5396 | ---------------------- |
5397 | -- Predicates_Match -- | |
5398 | ---------------------- | |
5399 | ||
5400 | function Predicates_Match (T1, T2 : Entity_Id) return Boolean is | |
5401 | Pred1 : Node_Id; | |
5402 | Pred2 : Node_Id; | |
5403 | ||
5404 | begin | |
5405 | if Ada_Version < Ada_2012 then | |
5406 | return True; | |
5407 | ||
5408 | -- Both types must have predicates or lack them | |
5409 | ||
5410 | elsif Has_Predicates (T1) /= Has_Predicates (T2) then | |
5411 | return False; | |
5412 | ||
5413 | -- Check matching predicates | |
5414 | ||
5415 | else | |
5416 | Pred1 := | |
5417 | Get_Rep_Item | |
5418 | (T1, Name_Static_Predicate, Check_Parents => False); | |
5419 | Pred2 := | |
5420 | Get_Rep_Item | |
5421 | (T2, Name_Static_Predicate, Check_Parents => False); | |
5422 | ||
5423 | -- Subtypes statically match if the predicate comes from the | |
5424 | -- same declaration, which can only happen if one is a subtype | |
5425 | -- of the other and has no explicit predicate. | |
5426 | ||
5427 | -- Suppress warnings on order of actuals, which is otherwise | |
5428 | -- triggered by one of the two calls below. | |
5429 | ||
5430 | pragma Warnings (Off); | |
5431 | return Pred1 = Pred2 | |
5432 | or else (No (Pred1) and then Is_Subtype_Of (T1, T2)) | |
5433 | or else (No (Pred2) and then Is_Subtype_Of (T2, T1)); | |
5434 | pragma Warnings (On); | |
5435 | end if; | |
5436 | end Predicates_Match; | |
5437 | ||
fc3a3f3b RD |
5438 | --------------------------------------------- |
5439 | -- Real_Or_String_Static_Predicate_Matches -- | |
5440 | --------------------------------------------- | |
5441 | ||
5442 | function Real_Or_String_Static_Predicate_Matches | |
5443 | (Val : Node_Id; | |
5444 | Typ : Entity_Id) return Boolean | |
5445 | is | |
5446 | Expr : constant Node_Id := Static_Real_Or_String_Predicate (Typ); | |
5447 | -- The predicate expression from the type | |
5448 | ||
5449 | Pfun : constant Entity_Id := Predicate_Function (Typ); | |
5450 | -- The entity for the predicate function | |
5451 | ||
5452 | Ent_Name : constant Name_Id := Chars (First_Formal (Pfun)); | |
5453 | -- The name of the formal of the predicate function. Occurrences of the | |
5454 | -- type name in Expr have been rewritten as references to this formal, | |
5455 | -- and it has a unique name, so we can identify references by this name. | |
5456 | ||
5457 | Copy : Node_Id; | |
5458 | -- Copy of the predicate function tree | |
5459 | ||
5460 | function Process (N : Node_Id) return Traverse_Result; | |
5461 | -- Function used to process nodes during the traversal in which we will | |
5462 | -- find occurrences of the entity name, and replace such occurrences | |
5463 | -- by a real literal with the value to be tested. | |
5464 | ||
5465 | procedure Traverse is new Traverse_Proc (Process); | |
5466 | -- The actual traversal procedure | |
5467 | ||
5468 | ------------- | |
5469 | -- Process -- | |
5470 | ------------- | |
5471 | ||
5472 | function Process (N : Node_Id) return Traverse_Result is | |
5473 | begin | |
5474 | if Nkind (N) = N_Identifier and then Chars (N) = Ent_Name then | |
5475 | declare | |
5476 | Nod : constant Node_Id := New_Copy (Val); | |
5477 | begin | |
5478 | Set_Sloc (Nod, Sloc (N)); | |
5479 | Rewrite (N, Nod); | |
5480 | return Skip; | |
5481 | end; | |
5482 | ||
e4d04166 AC |
5483 | -- The predicate function may contain string-comparison operations |
5484 | -- that have been converted into calls to run-time array-comparison | |
5485 | -- routines. To evaluate the predicate statically, we recover the | |
5486 | -- original comparison operation and replace the occurrence of the | |
5487 | -- formal by the static string value. The actuals of the generated | |
5488 | -- call are of the form X'Address. | |
5489 | ||
5490 | elsif Nkind (N) in N_Op_Compare | |
5491 | and then Nkind (Left_Opnd (N)) = N_Function_Call | |
5492 | then | |
5493 | declare | |
5494 | C : constant Node_Id := Left_Opnd (N); | |
5495 | F : constant Node_Id := First (Parameter_Associations (C)); | |
5496 | L : constant Node_Id := Prefix (F); | |
5497 | R : constant Node_Id := Prefix (Next (F)); | |
5498 | ||
5499 | begin | |
5500 | -- If an operand is an entity name, it is the formal of the | |
5501 | -- predicate function, so replace it with the string value. | |
5502 | -- It may be either operand in the call. The other operand | |
5503 | -- is a static string from the original predicate. | |
5504 | ||
5505 | if Is_Entity_Name (L) then | |
5506 | Rewrite (Left_Opnd (N), New_Copy (Val)); | |
5507 | Rewrite (Right_Opnd (N), New_Copy (R)); | |
5508 | ||
5509 | else | |
5510 | Rewrite (Left_Opnd (N), New_Copy (L)); | |
5511 | Rewrite (Right_Opnd (N), New_Copy (Val)); | |
5512 | end if; | |
5513 | ||
5514 | return Skip; | |
5515 | end; | |
5516 | ||
fc3a3f3b RD |
5517 | else |
5518 | return OK; | |
5519 | end if; | |
5520 | end Process; | |
5521 | ||
5522 | -- Start of processing for Real_Or_String_Static_Predicate_Matches | |
5523 | ||
5524 | begin | |
5525 | -- First deal with special case of inherited predicate, where the | |
5526 | -- predicate expression looks like: | |
5527 | ||
9bdc432a | 5528 | -- xxPredicate (typ (Ent)) and then Expr |
fc3a3f3b RD |
5529 | |
5530 | -- where Expr is the predicate expression for this level, and the | |
9bdc432a | 5531 | -- left operand is the call to evaluate the inherited predicate. |
fc3a3f3b RD |
5532 | |
5533 | if Nkind (Expr) = N_And_Then | |
9bdc432a AC |
5534 | and then Nkind (Left_Opnd (Expr)) = N_Function_Call |
5535 | and then Is_Predicate_Function (Entity (Name (Left_Opnd (Expr)))) | |
fc3a3f3b RD |
5536 | then |
5537 | -- OK we have the inherited case, so make a call to evaluate the | |
5538 | -- inherited predicate. If that fails, so do we! | |
5539 | ||
5540 | if not | |
5541 | Real_Or_String_Static_Predicate_Matches | |
5542 | (Val => Val, | |
9bdc432a | 5543 | Typ => Etype (First_Formal (Entity (Name (Left_Opnd (Expr)))))) |
fc3a3f3b RD |
5544 | then |
5545 | return False; | |
5546 | end if; | |
5547 | ||
9bdc432a | 5548 | -- Use the right operand for the continued processing |
fc3a3f3b | 5549 | |
9bdc432a | 5550 | Copy := Copy_Separate_Tree (Right_Opnd (Expr)); |
fc3a3f3b | 5551 | |
622599c6 RD |
5552 | -- Case where call to predicate function appears on its own (this means |
5553 | -- that the predicate at this level is just inherited from the parent). | |
fc3a3f3b | 5554 | |
1b1d88b1 | 5555 | elsif Nkind (Expr) = N_Function_Call then |
622599c6 RD |
5556 | declare |
5557 | Typ : constant Entity_Id := | |
5558 | Etype (First_Formal (Entity (Name (Expr)))); | |
fc3a3f3b | 5559 | |
622599c6 RD |
5560 | begin |
5561 | -- If the inherited predicate is dynamic, just ignore it. We can't | |
5562 | -- go trying to evaluate a dynamic predicate as a static one! | |
fc3a3f3b | 5563 | |
622599c6 RD |
5564 | if Has_Dynamic_Predicate_Aspect (Typ) then |
5565 | return True; | |
5566 | ||
5567 | -- Otherwise inherited predicate is static, check for match | |
5568 | ||
5569 | else | |
5570 | return Real_Or_String_Static_Predicate_Matches (Val, Typ); | |
5571 | end if; | |
5572 | end; | |
fc3a3f3b | 5573 | |
622599c6 | 5574 | -- If not just an inherited predicate, copy whole expression |
fc3a3f3b RD |
5575 | |
5576 | else | |
5577 | Copy := Copy_Separate_Tree (Expr); | |
5578 | end if; | |
5579 | ||
5580 | -- Now we replace occurrences of the entity by the value | |
5581 | ||
5582 | Traverse (Copy); | |
5583 | ||
5584 | -- And analyze the resulting static expression to see if it is True | |
5585 | ||
5586 | Analyze_And_Resolve (Copy, Standard_Boolean); | |
5587 | return Is_True (Expr_Value (Copy)); | |
5588 | end Real_Or_String_Static_Predicate_Matches; | |
5589 | ||
996ae0b0 RK |
5590 | ------------------------- |
5591 | -- Rewrite_In_Raise_CE -- | |
5592 | ------------------------- | |
5593 | ||
5594 | procedure Rewrite_In_Raise_CE (N : Node_Id; Exp : Node_Id) is | |
edab6088 RD |
5595 | Typ : constant Entity_Id := Etype (N); |
5596 | Stat : constant Boolean := Is_Static_Expression (N); | |
996ae0b0 RK |
5597 | |
5598 | begin | |
edab6088 RD |
5599 | -- If we want to raise CE in the condition of a N_Raise_CE node, we |
5600 | -- can just clear the condition if the reason is appropriate. We do | |
5601 | -- not do this operation if the parent has a reason other than range | |
5602 | -- check failed, because otherwise we would change the reason. | |
996ae0b0 RK |
5603 | |
5604 | if Present (Parent (N)) | |
5605 | and then Nkind (Parent (N)) = N_Raise_Constraint_Error | |
edab6088 RD |
5606 | and then Reason (Parent (N)) = |
5607 | UI_From_Int (RT_Exception_Code'Pos (CE_Range_Check_Failed)) | |
996ae0b0 RK |
5608 | then |
5609 | Set_Condition (Parent (N), Empty); | |
5610 | ||
edab6088 | 5611 | -- Else build an explicit N_Raise_CE |
996ae0b0 RK |
5612 | |
5613 | else | |
07fc65c4 GB |
5614 | Rewrite (N, |
5615 | Make_Raise_Constraint_Error (Sloc (Exp), | |
5616 | Reason => CE_Range_Check_Failed)); | |
996ae0b0 RK |
5617 | Set_Raises_Constraint_Error (N); |
5618 | Set_Etype (N, Typ); | |
5619 | end if; | |
edab6088 RD |
5620 | |
5621 | -- Set proper flags in result | |
5622 | ||
5623 | Set_Raises_Constraint_Error (N, True); | |
5624 | Set_Is_Static_Expression (N, Stat); | |
996ae0b0 RK |
5625 | end Rewrite_In_Raise_CE; |
5626 | ||
5627 | --------------------- | |
5628 | -- String_Type_Len -- | |
5629 | --------------------- | |
5630 | ||
5631 | function String_Type_Len (Stype : Entity_Id) return Uint is | |
5632 | NT : constant Entity_Id := Etype (First_Index (Stype)); | |
5633 | T : Entity_Id; | |
5634 | ||
5635 | begin | |
5636 | if Is_OK_Static_Subtype (NT) then | |
5637 | T := NT; | |
5638 | else | |
5639 | T := Base_Type (NT); | |
5640 | end if; | |
5641 | ||
5642 | return Expr_Value (Type_High_Bound (T)) - | |
5643 | Expr_Value (Type_Low_Bound (T)) + 1; | |
5644 | end String_Type_Len; | |
5645 | ||
5646 | ------------------------------------ | |
5647 | -- Subtypes_Statically_Compatible -- | |
5648 | ------------------------------------ | |
5649 | ||
5650 | function Subtypes_Statically_Compatible | |
c97d7285 AC |
5651 | (T1 : Entity_Id; |
5652 | T2 : Entity_Id; | |
5653 | Formal_Derived_Matching : Boolean := False) return Boolean | |
996ae0b0 RK |
5654 | is |
5655 | begin | |
437f8c1e AC |
5656 | -- Scalar types |
5657 | ||
996ae0b0 RK |
5658 | if Is_Scalar_Type (T1) then |
5659 | ||
5660 | -- Definitely compatible if we match | |
5661 | ||
5662 | if Subtypes_Statically_Match (T1, T2) then | |
5663 | return True; | |
5664 | ||
5665 | -- If either subtype is nonstatic then they're not compatible | |
5666 | ||
edab6088 | 5667 | elsif not Is_OK_Static_Subtype (T1) |
ebb6b0bd | 5668 | or else |
edab6088 | 5669 | not Is_OK_Static_Subtype (T2) |
996ae0b0 RK |
5670 | then |
5671 | return False; | |
5672 | ||
5673 | -- If either type has constraint error bounds, then consider that | |
5674 | -- they match to avoid junk cascaded errors here. | |
5675 | ||
5676 | elsif not Is_OK_Static_Subtype (T1) | |
5677 | or else not Is_OK_Static_Subtype (T2) | |
5678 | then | |
5679 | return True; | |
5680 | ||
26df19ce AC |
5681 | -- Base types must match, but we don't check that (should we???) but |
5682 | -- we do at least check that both types are real, or both types are | |
5683 | -- not real. | |
996ae0b0 | 5684 | |
fbf5a39b | 5685 | elsif Is_Real_Type (T1) /= Is_Real_Type (T2) then |
996ae0b0 RK |
5686 | return False; |
5687 | ||
5688 | -- Here we check the bounds | |
5689 | ||
5690 | else | |
5691 | declare | |
5692 | LB1 : constant Node_Id := Type_Low_Bound (T1); | |
5693 | HB1 : constant Node_Id := Type_High_Bound (T1); | |
5694 | LB2 : constant Node_Id := Type_Low_Bound (T2); | |
5695 | HB2 : constant Node_Id := Type_High_Bound (T2); | |
5696 | ||
5697 | begin | |
5698 | if Is_Real_Type (T1) then | |
5699 | return | |
5700 | (Expr_Value_R (LB1) > Expr_Value_R (HB1)) | |
5701 | or else | |
5702 | (Expr_Value_R (LB2) <= Expr_Value_R (LB1) | |
5703 | and then | |
5704 | Expr_Value_R (HB1) <= Expr_Value_R (HB2)); | |
5705 | ||
5706 | else | |
5707 | return | |
5708 | (Expr_Value (LB1) > Expr_Value (HB1)) | |
5709 | or else | |
5710 | (Expr_Value (LB2) <= Expr_Value (LB1) | |
5711 | and then | |
5712 | Expr_Value (HB1) <= Expr_Value (HB2)); | |
5713 | end if; | |
5714 | end; | |
5715 | end if; | |
5716 | ||
437f8c1e AC |
5717 | -- Access types |
5718 | ||
996ae0b0 | 5719 | elsif Is_Access_Type (T1) then |
26df19ce AC |
5720 | return (not Is_Constrained (T2) |
5721 | or else (Subtypes_Statically_Match | |
5722 | (Designated_Type (T1), Designated_Type (T2)))) | |
5723 | and then not (Can_Never_Be_Null (T2) | |
5724 | and then not Can_Never_Be_Null (T1)); | |
437f8c1e AC |
5725 | |
5726 | -- All other cases | |
996ae0b0 RK |
5727 | |
5728 | else | |
5729 | return (Is_Composite_Type (T1) and then not Is_Constrained (T2)) | |
c97d7285 | 5730 | or else Subtypes_Statically_Match (T1, T2, Formal_Derived_Matching); |
996ae0b0 RK |
5731 | end if; |
5732 | end Subtypes_Statically_Compatible; | |
5733 | ||
5734 | ------------------------------- | |
5735 | -- Subtypes_Statically_Match -- | |
5736 | ------------------------------- | |
5737 | ||
5738 | -- Subtypes statically match if they have statically matching constraints | |
5739 | -- (RM 4.9.1(2)). Constraints statically match if there are none, or if | |
5740 | -- they are the same identical constraint, or if they are static and the | |
5741 | -- values match (RM 4.9.1(1)). | |
5742 | ||
a0367005 | 5743 | -- In addition, in GNAT, the object size (Esize) values of the types must |
c97d7285 AC |
5744 | -- match if they are set (unless checking an actual for a formal derived |
5745 | -- type). The use of 'Object_Size can cause this to be false even if the | |
5746 | -- types would otherwise match in the RM sense. | |
5747 | ||
5748 | function Subtypes_Statically_Match | |
5749 | (T1 : Entity_Id; | |
5750 | T2 : Entity_Id; | |
5751 | Formal_Derived_Matching : Boolean := False) return Boolean | |
5752 | is | |
996ae0b0 RK |
5753 | begin |
5754 | -- A type always statically matches itself | |
5755 | ||
5756 | if T1 = T2 then | |
5757 | return True; | |
5758 | ||
c97d7285 AC |
5759 | -- No match if sizes different (from use of 'Object_Size). This test |
5760 | -- is excluded if Formal_Derived_Matching is True, as the base types | |
5761 | -- can be different in that case and typically have different sizes | |
5762 | -- (and Esizes can be set when Frontend_Layout_On_Target is True). | |
a0367005 | 5763 | |
c97d7285 | 5764 | elsif not Formal_Derived_Matching |
ebb6b0bd AC |
5765 | and then Known_Static_Esize (T1) |
5766 | and then Known_Static_Esize (T2) | |
a0367005 RD |
5767 | and then Esize (T1) /= Esize (T2) |
5768 | then | |
5769 | return False; | |
5770 | ||
308aab0b AC |
5771 | -- No match if predicates do not match |
5772 | ||
7f568bfa | 5773 | elsif not Predicates_Match (T1, T2) then |
308aab0b AC |
5774 | return False; |
5775 | ||
996ae0b0 RK |
5776 | -- Scalar types |
5777 | ||
5778 | elsif Is_Scalar_Type (T1) then | |
5779 | ||
5780 | -- Base types must be the same | |
5781 | ||
5782 | if Base_Type (T1) /= Base_Type (T2) then | |
5783 | return False; | |
5784 | end if; | |
5785 | ||
5786 | -- A constrained numeric subtype never matches an unconstrained | |
5787 | -- subtype, i.e. both types must be constrained or unconstrained. | |
5788 | ||
305caf42 AC |
5789 | -- To understand the requirement for this test, see RM 4.9.1(1). |
5790 | -- As is made clear in RM 3.5.4(11), type Integer, for example is | |
5791 | -- a constrained subtype with constraint bounds matching the bounds | |
5792 | -- of its corresponding unconstrained base type. In this situation, | |
5793 | -- Integer and Integer'Base do not statically match, even though | |
5794 | -- they have the same bounds. | |
996ae0b0 | 5795 | |
22cb89b5 AC |
5796 | -- We only apply this test to types in Standard and types that appear |
5797 | -- in user programs. That way, we do not have to be too careful about | |
5798 | -- setting Is_Constrained right for Itypes. | |
996ae0b0 RK |
5799 | |
5800 | if Is_Numeric_Type (T1) | |
5801 | and then (Is_Constrained (T1) /= Is_Constrained (T2)) | |
5802 | and then (Scope (T1) = Standard_Standard | |
5803 | or else Comes_From_Source (T1)) | |
5804 | and then (Scope (T2) = Standard_Standard | |
5805 | or else Comes_From_Source (T2)) | |
5806 | then | |
5807 | return False; | |
82c80734 | 5808 | |
22cb89b5 AC |
5809 | -- A generic scalar type does not statically match its base type |
5810 | -- (AI-311). In this case we make sure that the formals, which are | |
5811 | -- first subtypes of their bases, are constrained. | |
82c80734 RD |
5812 | |
5813 | elsif Is_Generic_Type (T1) | |
5814 | and then Is_Generic_Type (T2) | |
5815 | and then (Is_Constrained (T1) /= Is_Constrained (T2)) | |
5816 | then | |
5817 | return False; | |
996ae0b0 RK |
5818 | end if; |
5819 | ||
22cb89b5 AC |
5820 | -- If there was an error in either range, then just assume the types |
5821 | -- statically match to avoid further junk errors. | |
996ae0b0 | 5822 | |
199c6a10 AC |
5823 | if No (Scalar_Range (T1)) or else No (Scalar_Range (T2)) |
5824 | or else Error_Posted (Scalar_Range (T1)) | |
5825 | or else Error_Posted (Scalar_Range (T2)) | |
996ae0b0 RK |
5826 | then |
5827 | return True; | |
5828 | end if; | |
5829 | ||
308aab0b | 5830 | -- Otherwise both types have bounds that can be compared |
996ae0b0 RK |
5831 | |
5832 | declare | |
5833 | LB1 : constant Node_Id := Type_Low_Bound (T1); | |
5834 | HB1 : constant Node_Id := Type_High_Bound (T1); | |
5835 | LB2 : constant Node_Id := Type_Low_Bound (T2); | |
5836 | HB2 : constant Node_Id := Type_High_Bound (T2); | |
5837 | ||
5838 | begin | |
308aab0b | 5839 | -- If the bounds are the same tree node, then match (common case) |
996ae0b0 RK |
5840 | |
5841 | if LB1 = LB2 and then HB1 = HB2 then | |
308aab0b | 5842 | return True; |
996ae0b0 RK |
5843 | |
5844 | -- Otherwise bounds must be static and identical value | |
5845 | ||
5846 | else | |
edab6088 RD |
5847 | if not Is_OK_Static_Subtype (T1) |
5848 | or else not Is_OK_Static_Subtype (T2) | |
996ae0b0 RK |
5849 | then |
5850 | return False; | |
5851 | ||
22cb89b5 AC |
5852 | -- If either type has constraint error bounds, then say that |
5853 | -- they match to avoid junk cascaded errors here. | |
996ae0b0 RK |
5854 | |
5855 | elsif not Is_OK_Static_Subtype (T1) | |
5856 | or else not Is_OK_Static_Subtype (T2) | |
5857 | then | |
5858 | return True; | |
5859 | ||
5860 | elsif Is_Real_Type (T1) then | |
5861 | return | |
5862 | (Expr_Value_R (LB1) = Expr_Value_R (LB2)) | |
5863 | and then | |
5864 | (Expr_Value_R (HB1) = Expr_Value_R (HB2)); | |
5865 | ||
5866 | else | |
5867 | return | |
5868 | Expr_Value (LB1) = Expr_Value (LB2) | |
5869 | and then | |
5870 | Expr_Value (HB1) = Expr_Value (HB2); | |
5871 | end if; | |
5872 | end if; | |
5873 | end; | |
5874 | ||
5875 | -- Type with discriminants | |
5876 | ||
5877 | elsif Has_Discriminants (T1) or else Has_Discriminants (T2) then | |
6eaf4095 | 5878 | |
c2bf339e GD |
5879 | -- Because of view exchanges in multiple instantiations, conformance |
5880 | -- checking might try to match a partial view of a type with no | |
5881 | -- discriminants with a full view that has defaulted discriminants. | |
5882 | -- In such a case, use the discriminant constraint of the full view, | |
5883 | -- which must exist because we know that the two subtypes have the | |
5884 | -- same base type. | |
6eaf4095 | 5885 | |
996ae0b0 | 5886 | if Has_Discriminants (T1) /= Has_Discriminants (T2) then |
e699b76e AC |
5887 | -- A generic actual type is declared through a subtype declaration |
5888 | -- and may have an inconsistent indication of the presence of | |
5889 | -- discriminants, so check the type it renames. | |
5890 | ||
5891 | if Is_Generic_Actual_Type (T1) | |
5892 | and then not Has_Discriminants (Etype (T1)) | |
5893 | and then not Has_Discriminants (T2) | |
5894 | then | |
5895 | return True; | |
5896 | ||
5897 | elsif In_Instance then | |
c2bf339e GD |
5898 | if Is_Private_Type (T2) |
5899 | and then Present (Full_View (T2)) | |
5900 | and then Has_Discriminants (Full_View (T2)) | |
5901 | then | |
5902 | return Subtypes_Statically_Match (T1, Full_View (T2)); | |
5903 | ||
5904 | elsif Is_Private_Type (T1) | |
5905 | and then Present (Full_View (T1)) | |
5906 | and then Has_Discriminants (Full_View (T1)) | |
5907 | then | |
5908 | return Subtypes_Statically_Match (Full_View (T1), T2); | |
5909 | ||
5910 | else | |
5911 | return False; | |
5912 | end if; | |
6eaf4095 ES |
5913 | else |
5914 | return False; | |
5915 | end if; | |
996ae0b0 RK |
5916 | end if; |
5917 | ||
5918 | declare | |
5919 | DL1 : constant Elist_Id := Discriminant_Constraint (T1); | |
5920 | DL2 : constant Elist_Id := Discriminant_Constraint (T2); | |
5921 | ||
13f34a3f RD |
5922 | DA1 : Elmt_Id; |
5923 | DA2 : Elmt_Id; | |
996ae0b0 RK |
5924 | |
5925 | begin | |
5926 | if DL1 = DL2 then | |
5927 | return True; | |
996ae0b0 RK |
5928 | elsif Is_Constrained (T1) /= Is_Constrained (T2) then |
5929 | return False; | |
5930 | end if; | |
5931 | ||
13f34a3f | 5932 | -- Now loop through the discriminant constraints |
996ae0b0 | 5933 | |
13f34a3f RD |
5934 | -- Note: the guard here seems necessary, since it is possible at |
5935 | -- least for DL1 to be No_Elist. Not clear this is reasonable ??? | |
996ae0b0 | 5936 | |
13f34a3f RD |
5937 | if Present (DL1) and then Present (DL2) then |
5938 | DA1 := First_Elmt (DL1); | |
5939 | DA2 := First_Elmt (DL2); | |
5940 | while Present (DA1) loop | |
5941 | declare | |
5942 | Expr1 : constant Node_Id := Node (DA1); | |
5943 | Expr2 : constant Node_Id := Node (DA2); | |
996ae0b0 | 5944 | |
13f34a3f | 5945 | begin |
edab6088 RD |
5946 | if not Is_OK_Static_Expression (Expr1) |
5947 | or else not Is_OK_Static_Expression (Expr2) | |
13f34a3f RD |
5948 | then |
5949 | return False; | |
996ae0b0 | 5950 | |
13f34a3f RD |
5951 | -- If either expression raised a constraint error, |
5952 | -- consider the expressions as matching, since this | |
5953 | -- helps to prevent cascading errors. | |
5954 | ||
5955 | elsif Raises_Constraint_Error (Expr1) | |
5956 | or else Raises_Constraint_Error (Expr2) | |
5957 | then | |
5958 | null; | |
5959 | ||
5960 | elsif Expr_Value (Expr1) /= Expr_Value (Expr2) then | |
5961 | return False; | |
5962 | end if; | |
5963 | end; | |
996ae0b0 | 5964 | |
13f34a3f RD |
5965 | Next_Elmt (DA1); |
5966 | Next_Elmt (DA2); | |
5967 | end loop; | |
5968 | end if; | |
996ae0b0 RK |
5969 | end; |
5970 | ||
5971 | return True; | |
5972 | ||
22cb89b5 | 5973 | -- A definite type does not match an indefinite or classwide type. |
0356699b RD |
5974 | -- However, a generic type with unknown discriminants may be |
5975 | -- instantiated with a type with no discriminants, and conformance | |
22cb89b5 AC |
5976 | -- checking on an inherited operation may compare the actual with the |
5977 | -- subtype that renames it in the instance. | |
996ae0b0 | 5978 | |
80298c3b | 5979 | elsif Has_Unknown_Discriminants (T1) /= Has_Unknown_Discriminants (T2) |
996ae0b0 | 5980 | then |
7a3f77d2 AC |
5981 | return |
5982 | Is_Generic_Actual_Type (T1) or else Is_Generic_Actual_Type (T2); | |
996ae0b0 RK |
5983 | |
5984 | -- Array type | |
5985 | ||
5986 | elsif Is_Array_Type (T1) then | |
5987 | ||
22cb89b5 | 5988 | -- If either subtype is unconstrained then both must be, and if both |
308e6f3a | 5989 | -- are unconstrained then no further checking is needed. |
996ae0b0 RK |
5990 | |
5991 | if not Is_Constrained (T1) or else not Is_Constrained (T2) then | |
5992 | return not (Is_Constrained (T1) or else Is_Constrained (T2)); | |
5993 | end if; | |
5994 | ||
22cb89b5 AC |
5995 | -- Both subtypes are constrained, so check that the index subtypes |
5996 | -- statically match. | |
996ae0b0 RK |
5997 | |
5998 | declare | |
5999 | Index1 : Node_Id := First_Index (T1); | |
6000 | Index2 : Node_Id := First_Index (T2); | |
6001 | ||
6002 | begin | |
6003 | while Present (Index1) loop | |
6004 | if not | |
6005 | Subtypes_Statically_Match (Etype (Index1), Etype (Index2)) | |
6006 | then | |
6007 | return False; | |
6008 | end if; | |
6009 | ||
6010 | Next_Index (Index1); | |
6011 | Next_Index (Index2); | |
6012 | end loop; | |
6013 | ||
6014 | return True; | |
6015 | end; | |
6016 | ||
6017 | elsif Is_Access_Type (T1) then | |
b5bd964f ES |
6018 | if Can_Never_Be_Null (T1) /= Can_Never_Be_Null (T2) then |
6019 | return False; | |
6020 | ||
e1b871e9 AC |
6021 | elsif Ekind_In (T1, E_Access_Subprogram_Type, |
6022 | E_Anonymous_Access_Subprogram_Type) | |
7a3f77d2 | 6023 | then |
b5bd964f ES |
6024 | return |
6025 | Subtype_Conformant | |
6026 | (Designated_Type (T1), | |
bb98fe75 | 6027 | Designated_Type (T2)); |
b5bd964f ES |
6028 | else |
6029 | return | |
6030 | Subtypes_Statically_Match | |
6031 | (Designated_Type (T1), | |
6032 | Designated_Type (T2)) | |
6033 | and then Is_Access_Constant (T1) = Is_Access_Constant (T2); | |
6034 | end if; | |
996ae0b0 RK |
6035 | |
6036 | -- All other types definitely match | |
6037 | ||
6038 | else | |
6039 | return True; | |
6040 | end if; | |
6041 | end Subtypes_Statically_Match; | |
6042 | ||
6043 | ---------- | |
6044 | -- Test -- | |
6045 | ---------- | |
6046 | ||
6047 | function Test (Cond : Boolean) return Uint is | |
6048 | begin | |
6049 | if Cond then | |
6050 | return Uint_1; | |
6051 | else | |
6052 | return Uint_0; | |
6053 | end if; | |
6054 | end Test; | |
6055 | ||
634a926b AC |
6056 | --------------------- |
6057 | -- Test_Comparison -- | |
6058 | --------------------- | |
6059 | ||
6060 | procedure Test_Comparison | |
6061 | (Op : Node_Id; | |
6062 | Assume_Valid : Boolean; | |
6063 | True_Result : out Boolean; | |
6064 | False_Result : out Boolean) | |
6065 | is | |
6066 | Left : constant Node_Id := Left_Opnd (Op); | |
6067 | Left_Typ : constant Entity_Id := Etype (Left); | |
6068 | Orig_Op : constant Node_Id := Original_Node (Op); | |
6069 | ||
6070 | procedure Replacement_Warning (Msg : String); | |
6071 | -- Emit a warning on a comparison which can be replaced by '=' | |
6072 | ||
6073 | ------------------------- | |
6074 | -- Replacement_Warning -- | |
6075 | ------------------------- | |
6076 | ||
6077 | procedure Replacement_Warning (Msg : String) is | |
6078 | begin | |
6079 | if Constant_Condition_Warnings | |
6080 | and then Comes_From_Source (Orig_Op) | |
6081 | and then Is_Integer_Type (Left_Typ) | |
6082 | and then not Error_Posted (Op) | |
6083 | and then not Has_Warnings_Off (Left_Typ) | |
6084 | and then not In_Instance | |
6085 | then | |
6086 | Error_Msg_N (Msg, Op); | |
6087 | end if; | |
6088 | end Replacement_Warning; | |
6089 | ||
6090 | -- Local variables | |
6091 | ||
6092 | Res : constant Compare_Result := | |
6093 | Compile_Time_Compare (Left, Right_Opnd (Op), Assume_Valid); | |
6094 | ||
6095 | -- Start of processing for Test_Comparison | |
6096 | ||
6097 | begin | |
6098 | case N_Op_Compare (Nkind (Op)) is | |
6099 | when N_Op_Eq => | |
6100 | True_Result := Res = EQ; | |
6101 | False_Result := Res = LT or else Res = GT or else Res = NE; | |
6102 | ||
6103 | when N_Op_Ge => | |
6104 | True_Result := Res in Compare_GE; | |
6105 | False_Result := Res = LT; | |
6106 | ||
6107 | if Res = LE and then Nkind (Orig_Op) = N_Op_Ge then | |
6108 | Replacement_Warning | |
6109 | ("can never be greater than, could replace by ""'=""?c?"); | |
6110 | end if; | |
6111 | ||
6112 | when N_Op_Gt => | |
6113 | True_Result := Res = GT; | |
6114 | False_Result := Res in Compare_LE; | |
6115 | ||
6116 | when N_Op_Le => | |
6117 | True_Result := Res in Compare_LE; | |
6118 | False_Result := Res = GT; | |
6119 | ||
6120 | if Res = GE and then Nkind (Orig_Op) = N_Op_Le then | |
6121 | Replacement_Warning | |
6122 | ("can never be less than, could replace by ""'=""?c?"); | |
6123 | end if; | |
6124 | ||
6125 | when N_Op_Lt => | |
6126 | True_Result := Res = LT; | |
6127 | False_Result := Res in Compare_GE; | |
6128 | ||
6129 | when N_Op_Ne => | |
6130 | True_Result := Res = NE or else Res = GT or else Res = LT; | |
6131 | False_Result := Res = EQ; | |
6132 | end case; | |
6133 | end Test_Comparison; | |
6134 | ||
996ae0b0 RK |
6135 | --------------------------------- |
6136 | -- Test_Expression_Is_Foldable -- | |
6137 | --------------------------------- | |
6138 | ||
6139 | -- One operand case | |
6140 | ||
6141 | procedure Test_Expression_Is_Foldable | |
6142 | (N : Node_Id; | |
6143 | Op1 : Node_Id; | |
6144 | Stat : out Boolean; | |
6145 | Fold : out Boolean) | |
6146 | is | |
6147 | begin | |
6148 | Stat := False; | |
0356699b RD |
6149 | Fold := False; |
6150 | ||
6151 | if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then | |
6152 | return; | |
6153 | end if; | |
996ae0b0 RK |
6154 | |
6155 | -- If operand is Any_Type, just propagate to result and do not | |
6156 | -- try to fold, this prevents cascaded errors. | |
6157 | ||
6158 | if Etype (Op1) = Any_Type then | |
6159 | Set_Etype (N, Any_Type); | |
996ae0b0 RK |
6160 | return; |
6161 | ||
6162 | -- If operand raises constraint error, then replace node N with the | |
6163 | -- raise constraint error node, and we are obviously not foldable. | |
6164 | -- Note that this replacement inherits the Is_Static_Expression flag | |
6165 | -- from the operand. | |
6166 | ||
6167 | elsif Raises_Constraint_Error (Op1) then | |
6168 | Rewrite_In_Raise_CE (N, Op1); | |
996ae0b0 RK |
6169 | return; |
6170 | ||
6171 | -- If the operand is not static, then the result is not static, and | |
6172 | -- all we have to do is to check the operand since it is now known | |
6173 | -- to appear in a non-static context. | |
6174 | ||
6175 | elsif not Is_Static_Expression (Op1) then | |
6176 | Check_Non_Static_Context (Op1); | |
6177 | Fold := Compile_Time_Known_Value (Op1); | |
6178 | return; | |
6179 | ||
6180 | -- An expression of a formal modular type is not foldable because | |
6181 | -- the modulus is unknown. | |
6182 | ||
6183 | elsif Is_Modular_Integer_Type (Etype (Op1)) | |
6184 | and then Is_Generic_Type (Etype (Op1)) | |
6185 | then | |
6186 | Check_Non_Static_Context (Op1); | |
996ae0b0 RK |
6187 | return; |
6188 | ||
6189 | -- Here we have the case of an operand whose type is OK, which is | |
6190 | -- static, and which does not raise constraint error, we can fold. | |
6191 | ||
6192 | else | |
6193 | Set_Is_Static_Expression (N); | |
6194 | Fold := True; | |
6195 | Stat := True; | |
6196 | end if; | |
6197 | end Test_Expression_Is_Foldable; | |
6198 | ||
6199 | -- Two operand case | |
6200 | ||
6201 | procedure Test_Expression_Is_Foldable | |
6c3c671e AC |
6202 | (N : Node_Id; |
6203 | Op1 : Node_Id; | |
6204 | Op2 : Node_Id; | |
6205 | Stat : out Boolean; | |
6206 | Fold : out Boolean; | |
6207 | CRT_Safe : Boolean := False) | |
996ae0b0 RK |
6208 | is |
6209 | Rstat : constant Boolean := Is_Static_Expression (Op1) | |
80298c3b AC |
6210 | and then |
6211 | Is_Static_Expression (Op2); | |
996ae0b0 RK |
6212 | |
6213 | begin | |
6214 | Stat := False; | |
0356699b RD |
6215 | Fold := False; |
6216 | ||
4a28b181 AC |
6217 | -- Inhibit folding if -gnatd.f flag set |
6218 | ||
0356699b RD |
6219 | if Debug_Flag_Dot_F and then In_Extended_Main_Source_Unit (N) then |
6220 | return; | |
6221 | end if; | |
996ae0b0 RK |
6222 | |
6223 | -- If either operand is Any_Type, just propagate to result and | |
6224 | -- do not try to fold, this prevents cascaded errors. | |
6225 | ||
6226 | if Etype (Op1) = Any_Type or else Etype (Op2) = Any_Type then | |
6227 | Set_Etype (N, Any_Type); | |
996ae0b0 RK |
6228 | return; |
6229 | ||
22cb89b5 AC |
6230 | -- If left operand raises constraint error, then replace node N with the |
6231 | -- Raise_Constraint_Error node, and we are obviously not foldable. | |
996ae0b0 RK |
6232 | -- Is_Static_Expression is set from the two operands in the normal way, |
6233 | -- and we check the right operand if it is in a non-static context. | |
6234 | ||
6235 | elsif Raises_Constraint_Error (Op1) then | |
6236 | if not Rstat then | |
6237 | Check_Non_Static_Context (Op2); | |
6238 | end if; | |
6239 | ||
6240 | Rewrite_In_Raise_CE (N, Op1); | |
6241 | Set_Is_Static_Expression (N, Rstat); | |
996ae0b0 RK |
6242 | return; |
6243 | ||
22cb89b5 AC |
6244 | -- Similar processing for the case of the right operand. Note that we |
6245 | -- don't use this routine for the short-circuit case, so we do not have | |
6246 | -- to worry about that special case here. | |
996ae0b0 RK |
6247 | |
6248 | elsif Raises_Constraint_Error (Op2) then | |
6249 | if not Rstat then | |
6250 | Check_Non_Static_Context (Op1); | |
6251 | end if; | |
6252 | ||
6253 | Rewrite_In_Raise_CE (N, Op2); | |
6254 | Set_Is_Static_Expression (N, Rstat); | |
996ae0b0 RK |
6255 | return; |
6256 | ||
82c80734 | 6257 | -- Exclude expressions of a generic modular type, as above |
996ae0b0 RK |
6258 | |
6259 | elsif Is_Modular_Integer_Type (Etype (Op1)) | |
6260 | and then Is_Generic_Type (Etype (Op1)) | |
6261 | then | |
6262 | Check_Non_Static_Context (Op1); | |
996ae0b0 RK |
6263 | return; |
6264 | ||
6265 | -- If result is not static, then check non-static contexts on operands | |
22cb89b5 | 6266 | -- since one of them may be static and the other one may not be static. |
996ae0b0 RK |
6267 | |
6268 | elsif not Rstat then | |
6269 | Check_Non_Static_Context (Op1); | |
6270 | Check_Non_Static_Context (Op2); | |
6c3c671e AC |
6271 | |
6272 | if CRT_Safe then | |
6273 | Fold := CRT_Safe_Compile_Time_Known_Value (Op1) | |
6274 | and then CRT_Safe_Compile_Time_Known_Value (Op2); | |
6275 | else | |
6276 | Fold := Compile_Time_Known_Value (Op1) | |
6277 | and then Compile_Time_Known_Value (Op2); | |
6278 | end if; | |
6279 | ||
996ae0b0 RK |
6280 | return; |
6281 | ||
22cb89b5 AC |
6282 | -- Else result is static and foldable. Both operands are static, and |
6283 | -- neither raises constraint error, so we can definitely fold. | |
996ae0b0 RK |
6284 | |
6285 | else | |
6286 | Set_Is_Static_Expression (N); | |
6287 | Fold := True; | |
6288 | Stat := True; | |
6289 | return; | |
6290 | end if; | |
6291 | end Test_Expression_Is_Foldable; | |
6292 | ||
305caf42 AC |
6293 | ------------------- |
6294 | -- Test_In_Range -- | |
6295 | ------------------- | |
6296 | ||
6297 | function Test_In_Range | |
6298 | (N : Node_Id; | |
6299 | Typ : Entity_Id; | |
6300 | Assume_Valid : Boolean; | |
6301 | Fixed_Int : Boolean; | |
6302 | Int_Real : Boolean) return Range_Membership | |
6303 | is | |
6304 | Val : Uint; | |
6305 | Valr : Ureal; | |
6306 | ||
6307 | pragma Warnings (Off, Assume_Valid); | |
6308 | -- For now Assume_Valid is unreferenced since the current implementation | |
6309 | -- always returns Unknown if N is not a compile time known value, but we | |
6310 | -- keep the parameter to allow for future enhancements in which we try | |
6311 | -- to get the information in the variable case as well. | |
6312 | ||
6313 | begin | |
8bef7ba9 AC |
6314 | -- If an error was posted on expression, then return Unknown, we do not |
6315 | -- want cascaded errors based on some false analysis of a junk node. | |
6316 | ||
6317 | if Error_Posted (N) then | |
6318 | return Unknown; | |
6319 | ||
7b536495 AC |
6320 | -- Expression that raises constraint error is an odd case. We certainly |
6321 | -- do not want to consider it to be in range. It might make sense to | |
6322 | -- consider it always out of range, but this causes incorrect error | |
6323 | -- messages about static expressions out of range. So we just return | |
6324 | -- Unknown, which is always safe. | |
6325 | ||
8bef7ba9 | 6326 | elsif Raises_Constraint_Error (N) then |
7b536495 AC |
6327 | return Unknown; |
6328 | ||
305caf42 AC |
6329 | -- Universal types have no range limits, so always in range |
6330 | ||
7b536495 | 6331 | elsif Typ = Universal_Integer or else Typ = Universal_Real then |
305caf42 AC |
6332 | return In_Range; |
6333 | ||
6334 | -- Never known if not scalar type. Don't know if this can actually | |
a90bd866 | 6335 | -- happen, but our spec allows it, so we must check. |
305caf42 AC |
6336 | |
6337 | elsif not Is_Scalar_Type (Typ) then | |
6338 | return Unknown; | |
6339 | ||
6340 | -- Never known if this is a generic type, since the bounds of generic | |
6341 | -- types are junk. Note that if we only checked for static expressions | |
6342 | -- (instead of compile time known values) below, we would not need this | |
6343 | -- check, because values of a generic type can never be static, but they | |
6344 | -- can be known at compile time. | |
6345 | ||
6346 | elsif Is_Generic_Type (Typ) then | |
6347 | return Unknown; | |
6348 | ||
7b536495 AC |
6349 | -- Case of a known compile time value, where we can check if it is in |
6350 | -- the bounds of the given type. | |
305caf42 | 6351 | |
7b536495 | 6352 | elsif Compile_Time_Known_Value (N) then |
305caf42 AC |
6353 | declare |
6354 | Lo : Node_Id; | |
6355 | Hi : Node_Id; | |
6356 | ||
6357 | LB_Known : Boolean; | |
6358 | HB_Known : Boolean; | |
6359 | ||
6360 | begin | |
6361 | Lo := Type_Low_Bound (Typ); | |
6362 | Hi := Type_High_Bound (Typ); | |
6363 | ||
6364 | LB_Known := Compile_Time_Known_Value (Lo); | |
6365 | HB_Known := Compile_Time_Known_Value (Hi); | |
6366 | ||
6367 | -- Fixed point types should be considered as such only if flag | |
6368 | -- Fixed_Int is set to False. | |
6369 | ||
6370 | if Is_Floating_Point_Type (Typ) | |
6371 | or else (Is_Fixed_Point_Type (Typ) and then not Fixed_Int) | |
6372 | or else Int_Real | |
6373 | then | |
6374 | Valr := Expr_Value_R (N); | |
6375 | ||
6376 | if LB_Known and HB_Known then | |
6377 | if Valr >= Expr_Value_R (Lo) | |
6378 | and then | |
6379 | Valr <= Expr_Value_R (Hi) | |
6380 | then | |
6381 | return In_Range; | |
6382 | else | |
6383 | return Out_Of_Range; | |
6384 | end if; | |
6385 | ||
6386 | elsif (LB_Known and then Valr < Expr_Value_R (Lo)) | |
6387 | or else | |
6388 | (HB_Known and then Valr > Expr_Value_R (Hi)) | |
6389 | then | |
6390 | return Out_Of_Range; | |
6391 | ||
6392 | else | |
6393 | return Unknown; | |
6394 | end if; | |
6395 | ||
6396 | else | |
6397 | Val := Expr_Value (N); | |
6398 | ||
6399 | if LB_Known and HB_Known then | |
80298c3b | 6400 | if Val >= Expr_Value (Lo) and then Val <= Expr_Value (Hi) |
305caf42 AC |
6401 | then |
6402 | return In_Range; | |
6403 | else | |
6404 | return Out_Of_Range; | |
6405 | end if; | |
6406 | ||
6407 | elsif (LB_Known and then Val < Expr_Value (Lo)) | |
6408 | or else | |
6409 | (HB_Known and then Val > Expr_Value (Hi)) | |
6410 | then | |
6411 | return Out_Of_Range; | |
6412 | ||
6413 | else | |
6414 | return Unknown; | |
6415 | end if; | |
6416 | end if; | |
6417 | end; | |
7b536495 AC |
6418 | |
6419 | -- Here for value not known at compile time. Case of expression subtype | |
6420 | -- is Typ or is a subtype of Typ, and we can assume expression is valid. | |
6421 | -- In this case we know it is in range without knowing its value. | |
6422 | ||
6423 | elsif Assume_Valid | |
6424 | and then (Etype (N) = Typ or else Is_Subtype_Of (Etype (N), Typ)) | |
6425 | then | |
6426 | return In_Range; | |
6427 | ||
6c56d9b8 AC |
6428 | -- Another special case. For signed integer types, if the target type |
6429 | -- has Is_Known_Valid set, and the source type does not have a larger | |
6430 | -- size, then the source value must be in range. We exclude biased | |
6431 | -- types, because they bizarrely can generate out of range values. | |
6432 | ||
6433 | elsif Is_Signed_Integer_Type (Etype (N)) | |
6434 | and then Is_Known_Valid (Typ) | |
6435 | and then Esize (Etype (N)) <= Esize (Typ) | |
6436 | and then not Has_Biased_Representation (Etype (N)) | |
6437 | then | |
6438 | return In_Range; | |
6439 | ||
7b536495 AC |
6440 | -- For all other cases, result is unknown |
6441 | ||
6442 | else | |
6443 | return Unknown; | |
305caf42 AC |
6444 | end if; |
6445 | end Test_In_Range; | |
6446 | ||
996ae0b0 RK |
6447 | -------------- |
6448 | -- To_Bits -- | |
6449 | -------------- | |
6450 | ||
6451 | procedure To_Bits (U : Uint; B : out Bits) is | |
6452 | begin | |
6453 | for J in 0 .. B'Last loop | |
6454 | B (J) := (U / (2 ** J)) mod 2 /= 0; | |
6455 | end loop; | |
6456 | end To_Bits; | |
6457 | ||
fbf5a39b AC |
6458 | -------------------- |
6459 | -- Why_Not_Static -- | |
6460 | -------------------- | |
6461 | ||
6462 | procedure Why_Not_Static (Expr : Node_Id) is | |
6463 | N : constant Node_Id := Original_Node (Expr); | |
6464 | Typ : Entity_Id; | |
6465 | E : Entity_Id; | |
edab6088 RD |
6466 | Alt : Node_Id; |
6467 | Exp : Node_Id; | |
fbf5a39b AC |
6468 | |
6469 | procedure Why_Not_Static_List (L : List_Id); | |
22cb89b5 AC |
6470 | -- A version that can be called on a list of expressions. Finds all |
6471 | -- non-static violations in any element of the list. | |
fbf5a39b AC |
6472 | |
6473 | ------------------------- | |
6474 | -- Why_Not_Static_List -- | |
6475 | ------------------------- | |
6476 | ||
6477 | procedure Why_Not_Static_List (L : List_Id) is | |
6478 | N : Node_Id; | |
fbf5a39b AC |
6479 | begin |
6480 | if Is_Non_Empty_List (L) then | |
6481 | N := First (L); | |
6482 | while Present (N) loop | |
6483 | Why_Not_Static (N); | |
6484 | Next (N); | |
6485 | end loop; | |
6486 | end if; | |
6487 | end Why_Not_Static_List; | |
6488 | ||
6489 | -- Start of processing for Why_Not_Static | |
6490 | ||
6491 | begin | |
fbf5a39b AC |
6492 | -- Ignore call on error or empty node |
6493 | ||
6494 | if No (Expr) or else Nkind (Expr) = N_Error then | |
6495 | return; | |
6496 | end if; | |
6497 | ||
6498 | -- Preprocessing for sub expressions | |
6499 | ||
6500 | if Nkind (Expr) in N_Subexpr then | |
6501 | ||
6502 | -- Nothing to do if expression is static | |
6503 | ||
6504 | if Is_OK_Static_Expression (Expr) then | |
6505 | return; | |
6506 | end if; | |
6507 | ||
6508 | -- Test for constraint error raised | |
6509 | ||
6510 | if Raises_Constraint_Error (Expr) then | |
edab6088 RD |
6511 | |
6512 | -- Special case membership to find out which piece to flag | |
6513 | ||
6514 | if Nkind (N) in N_Membership_Test then | |
6515 | if Raises_Constraint_Error (Left_Opnd (N)) then | |
6516 | Why_Not_Static (Left_Opnd (N)); | |
6517 | return; | |
6518 | ||
6519 | elsif Present (Right_Opnd (N)) | |
6520 | and then Raises_Constraint_Error (Right_Opnd (N)) | |
6521 | then | |
6522 | Why_Not_Static (Right_Opnd (N)); | |
6523 | return; | |
6524 | ||
6525 | else | |
6526 | pragma Assert (Present (Alternatives (N))); | |
6527 | ||
6528 | Alt := First (Alternatives (N)); | |
6529 | while Present (Alt) loop | |
6530 | if Raises_Constraint_Error (Alt) then | |
6531 | Why_Not_Static (Alt); | |
6532 | return; | |
6533 | else | |
6534 | Next (Alt); | |
6535 | end if; | |
6536 | end loop; | |
6537 | end if; | |
6538 | ||
6539 | -- Special case a range to find out which bound to flag | |
6540 | ||
6541 | elsif Nkind (N) = N_Range then | |
6542 | if Raises_Constraint_Error (Low_Bound (N)) then | |
6543 | Why_Not_Static (Low_Bound (N)); | |
6544 | return; | |
6545 | ||
6546 | elsif Raises_Constraint_Error (High_Bound (N)) then | |
6547 | Why_Not_Static (High_Bound (N)); | |
6548 | return; | |
6549 | end if; | |
6550 | ||
6551 | -- Special case attribute to see which part to flag | |
6552 | ||
6553 | elsif Nkind (N) = N_Attribute_Reference then | |
6554 | if Raises_Constraint_Error (Prefix (N)) then | |
6555 | Why_Not_Static (Prefix (N)); | |
6556 | return; | |
6557 | end if; | |
6558 | ||
6559 | if Present (Expressions (N)) then | |
6560 | Exp := First (Expressions (N)); | |
6561 | while Present (Exp) loop | |
6562 | if Raises_Constraint_Error (Exp) then | |
6563 | Why_Not_Static (Exp); | |
6564 | return; | |
6565 | end if; | |
6566 | ||
6567 | Next (Exp); | |
6568 | end loop; | |
6569 | end if; | |
6570 | ||
6571 | -- Special case a subtype name | |
6572 | ||
6573 | elsif Is_Entity_Name (Expr) and then Is_Type (Entity (Expr)) then | |
6574 | Error_Msg_NE | |
6575 | ("!& is not a static subtype (RM 4.9(26))", N, Entity (Expr)); | |
6576 | return; | |
6577 | end if; | |
6578 | ||
6579 | -- End of special cases | |
6580 | ||
fbf5a39b | 6581 | Error_Msg_N |
80298c3b AC |
6582 | ("!expression raises exception, cannot be static (RM 4.9(34))", |
6583 | N); | |
fbf5a39b AC |
6584 | return; |
6585 | end if; | |
6586 | ||
6587 | -- If no type, then something is pretty wrong, so ignore | |
6588 | ||
6589 | Typ := Etype (Expr); | |
6590 | ||
6591 | if No (Typ) then | |
6592 | return; | |
6593 | end if; | |
6594 | ||
65f7ed64 AC |
6595 | -- Type must be scalar or string type (but allow Bignum, since this |
6596 | -- is really a scalar type from our point of view in this diagnosis). | |
fbf5a39b AC |
6597 | |
6598 | if not Is_Scalar_Type (Typ) | |
6599 | and then not Is_String_Type (Typ) | |
65f7ed64 | 6600 | and then not Is_RTE (Typ, RE_Bignum) |
fbf5a39b AC |
6601 | then |
6602 | Error_Msg_N | |
c8a3028c | 6603 | ("!static expression must have scalar or string type " & |
8fde064e | 6604 | "(RM 4.9(2))", N); |
fbf5a39b AC |
6605 | return; |
6606 | end if; | |
6607 | end if; | |
6608 | ||
6609 | -- If we got through those checks, test particular node kind | |
6610 | ||
6611 | case Nkind (N) is | |
8fde064e AC |
6612 | |
6613 | -- Entity name | |
6614 | ||
d8f43ee6 HK |
6615 | when N_Expanded_Name |
6616 | | N_Identifier | |
6617 | | N_Operator_Symbol | |
6618 | => | |
fbf5a39b AC |
6619 | E := Entity (N); |
6620 | ||
6621 | if Is_Named_Number (E) then | |
6622 | null; | |
6623 | ||
6624 | elsif Ekind (E) = E_Constant then | |
8fde064e AC |
6625 | |
6626 | -- One case we can give a metter message is when we have a | |
6627 | -- string literal created by concatenating an aggregate with | |
6628 | -- an others expression. | |
6629 | ||
6630 | Entity_Case : declare | |
6631 | CV : constant Node_Id := Constant_Value (E); | |
6632 | CO : constant Node_Id := Original_Node (CV); | |
6633 | ||
6634 | function Is_Aggregate (N : Node_Id) return Boolean; | |
6635 | -- See if node N came from an others aggregate, if so | |
6636 | -- return True and set Error_Msg_Sloc to aggregate. | |
6637 | ||
6638 | ------------------ | |
6639 | -- Is_Aggregate -- | |
6640 | ------------------ | |
6641 | ||
6642 | function Is_Aggregate (N : Node_Id) return Boolean is | |
6643 | begin | |
6644 | if Nkind (Original_Node (N)) = N_Aggregate then | |
6645 | Error_Msg_Sloc := Sloc (Original_Node (N)); | |
6646 | return True; | |
80298c3b | 6647 | |
8fde064e AC |
6648 | elsif Is_Entity_Name (N) |
6649 | and then Ekind (Entity (N)) = E_Constant | |
6650 | and then | |
6651 | Nkind (Original_Node (Constant_Value (Entity (N)))) = | |
6652 | N_Aggregate | |
6653 | then | |
6654 | Error_Msg_Sloc := | |
6655 | Sloc (Original_Node (Constant_Value (Entity (N)))); | |
6656 | return True; | |
80298c3b | 6657 | |
8fde064e AC |
6658 | else |
6659 | return False; | |
6660 | end if; | |
6661 | end Is_Aggregate; | |
6662 | ||
6663 | -- Start of processing for Entity_Case | |
6664 | ||
6665 | begin | |
6666 | if Is_Aggregate (CV) | |
6667 | or else (Nkind (CO) = N_Op_Concat | |
6668 | and then (Is_Aggregate (Left_Opnd (CO)) | |
6669 | or else | |
6670 | Is_Aggregate (Right_Opnd (CO)))) | |
6671 | then | |
c8a3028c | 6672 | Error_Msg_N ("!aggregate (#) is never static", N); |
8fde064e | 6673 | |
aa500b7a | 6674 | elsif No (CV) or else not Is_Static_Expression (CV) then |
8fde064e | 6675 | Error_Msg_NE |
c8a3028c | 6676 | ("!& is not a static constant (RM 4.9(5))", N, E); |
8fde064e AC |
6677 | end if; |
6678 | end Entity_Case; | |
fbf5a39b | 6679 | |
edab6088 RD |
6680 | elsif Is_Type (E) then |
6681 | Error_Msg_NE | |
6682 | ("!& is not a static subtype (RM 4.9(26))", N, E); | |
6683 | ||
fbf5a39b AC |
6684 | else |
6685 | Error_Msg_NE | |
c8a3028c | 6686 | ("!& is not static constant or named number " |
8fde064e | 6687 | & "(RM 4.9(5))", N, E); |
fbf5a39b AC |
6688 | end if; |
6689 | ||
8fde064e AC |
6690 | -- Binary operator |
6691 | ||
d8f43ee6 HK |
6692 | when N_Binary_Op |
6693 | | N_Membership_Test | |
6694 | | N_Short_Circuit | |
6695 | => | |
fbf5a39b AC |
6696 | if Nkind (N) in N_Op_Shift then |
6697 | Error_Msg_N | |
d8f43ee6 | 6698 | ("!shift functions are never static (RM 4.9(6,18))", N); |
fbf5a39b AC |
6699 | else |
6700 | Why_Not_Static (Left_Opnd (N)); | |
6701 | Why_Not_Static (Right_Opnd (N)); | |
6702 | end if; | |
6703 | ||
8fde064e AC |
6704 | -- Unary operator |
6705 | ||
fbf5a39b AC |
6706 | when N_Unary_Op => |
6707 | Why_Not_Static (Right_Opnd (N)); | |
6708 | ||
8fde064e AC |
6709 | -- Attribute reference |
6710 | ||
fbf5a39b AC |
6711 | when N_Attribute_Reference => |
6712 | Why_Not_Static_List (Expressions (N)); | |
6713 | ||
6714 | E := Etype (Prefix (N)); | |
6715 | ||
6716 | if E = Standard_Void_Type then | |
6717 | return; | |
6718 | end if; | |
6719 | ||
6720 | -- Special case non-scalar'Size since this is a common error | |
6721 | ||
6722 | if Attribute_Name (N) = Name_Size then | |
6723 | Error_Msg_N | |
c8a3028c | 6724 | ("!size attribute is only static for static scalar type " |
8fde064e | 6725 | & "(RM 4.9(7,8))", N); |
fbf5a39b AC |
6726 | |
6727 | -- Flag array cases | |
6728 | ||
6729 | elsif Is_Array_Type (E) then | |
80298c3b AC |
6730 | if not Nam_In (Attribute_Name (N), Name_First, |
6731 | Name_Last, | |
6732 | Name_Length) | |
fbf5a39b AC |
6733 | then |
6734 | Error_Msg_N | |
c8a3028c | 6735 | ("!static array attribute must be Length, First, or Last " |
8fde064e | 6736 | & "(RM 4.9(8))", N); |
fbf5a39b AC |
6737 | |
6738 | -- Since we know the expression is not-static (we already | |
6739 | -- tested for this, must mean array is not static). | |
6740 | ||
6741 | else | |
6742 | Error_Msg_N | |
c8a3028c | 6743 | ("!prefix is non-static array (RM 4.9(8))", Prefix (N)); |
fbf5a39b AC |
6744 | end if; |
6745 | ||
6746 | return; | |
6747 | ||
22cb89b5 AC |
6748 | -- Special case generic types, since again this is a common source |
6749 | -- of confusion. | |
fbf5a39b | 6750 | |
80298c3b | 6751 | elsif Is_Generic_Actual_Type (E) or else Is_Generic_Type (E) then |
fbf5a39b | 6752 | Error_Msg_N |
c8a3028c | 6753 | ("!attribute of generic type is never static " |
8fde064e | 6754 | & "(RM 4.9(7,8))", N); |
fbf5a39b | 6755 | |
edab6088 | 6756 | elsif Is_OK_Static_Subtype (E) then |
fbf5a39b AC |
6757 | null; |
6758 | ||
6759 | elsif Is_Scalar_Type (E) then | |
6760 | Error_Msg_N | |
c8a3028c | 6761 | ("!prefix type for attribute is not static scalar subtype " |
8fde064e | 6762 | & "(RM 4.9(7))", N); |
fbf5a39b AC |
6763 | |
6764 | else | |
6765 | Error_Msg_N | |
c8a3028c | 6766 | ("!static attribute must apply to array/scalar type " |
8fde064e | 6767 | & "(RM 4.9(7,8))", N); |
fbf5a39b AC |
6768 | end if; |
6769 | ||
8fde064e AC |
6770 | -- String literal |
6771 | ||
fbf5a39b AC |
6772 | when N_String_Literal => |
6773 | Error_Msg_N | |
c8a3028c | 6774 | ("!subtype of string literal is non-static (RM 4.9(4))", N); |
8fde064e AC |
6775 | |
6776 | -- Explicit dereference | |
fbf5a39b AC |
6777 | |
6778 | when N_Explicit_Dereference => | |
6779 | Error_Msg_N | |
c8a3028c | 6780 | ("!explicit dereference is never static (RM 4.9)", N); |
8fde064e AC |
6781 | |
6782 | -- Function call | |
fbf5a39b AC |
6783 | |
6784 | when N_Function_Call => | |
6785 | Why_Not_Static_List (Parameter_Associations (N)); | |
65f7ed64 AC |
6786 | |
6787 | -- Complain about non-static function call unless we have Bignum | |
6788 | -- which means that the underlying expression is really some | |
6789 | -- scalar arithmetic operation. | |
6790 | ||
6791 | if not Is_RTE (Typ, RE_Bignum) then | |
c8a3028c | 6792 | Error_Msg_N ("!non-static function call (RM 4.9(6,18))", N); |
65f7ed64 | 6793 | end if; |
fbf5a39b | 6794 | |
8fde064e AC |
6795 | -- Parameter assocation (test actual parameter) |
6796 | ||
fbf5a39b AC |
6797 | when N_Parameter_Association => |
6798 | Why_Not_Static (Explicit_Actual_Parameter (N)); | |
6799 | ||
8fde064e AC |
6800 | -- Indexed component |
6801 | ||
fbf5a39b | 6802 | when N_Indexed_Component => |
c8a3028c | 6803 | Error_Msg_N ("!indexed component is never static (RM 4.9)", N); |
8fde064e AC |
6804 | |
6805 | -- Procedure call | |
fbf5a39b AC |
6806 | |
6807 | when N_Procedure_Call_Statement => | |
c8a3028c | 6808 | Error_Msg_N ("!procedure call is never static (RM 4.9)", N); |
8fde064e AC |
6809 | |
6810 | -- Qualified expression (test expression) | |
fbf5a39b AC |
6811 | |
6812 | when N_Qualified_Expression => | |
6813 | Why_Not_Static (Expression (N)); | |
6814 | ||
8fde064e AC |
6815 | -- Aggregate |
6816 | ||
d8f43ee6 HK |
6817 | when N_Aggregate |
6818 | | N_Extension_Aggregate | |
6819 | => | |
c8a3028c | 6820 | Error_Msg_N ("!an aggregate is never static (RM 4.9)", N); |
8fde064e AC |
6821 | |
6822 | -- Range | |
fbf5a39b AC |
6823 | |
6824 | when N_Range => | |
6825 | Why_Not_Static (Low_Bound (N)); | |
6826 | Why_Not_Static (High_Bound (N)); | |
6827 | ||
8fde064e AC |
6828 | -- Range constraint, test range expression |
6829 | ||
fbf5a39b AC |
6830 | when N_Range_Constraint => |
6831 | Why_Not_Static (Range_Expression (N)); | |
6832 | ||
8fde064e AC |
6833 | -- Subtype indication, test constraint |
6834 | ||
fbf5a39b AC |
6835 | when N_Subtype_Indication => |
6836 | Why_Not_Static (Constraint (N)); | |
6837 | ||
8fde064e AC |
6838 | -- Selected component |
6839 | ||
fbf5a39b | 6840 | when N_Selected_Component => |
c8a3028c | 6841 | Error_Msg_N ("!selected component is never static (RM 4.9)", N); |
8fde064e AC |
6842 | |
6843 | -- Slice | |
fbf5a39b AC |
6844 | |
6845 | when N_Slice => | |
c8a3028c | 6846 | Error_Msg_N ("!slice is never static (RM 4.9)", N); |
fbf5a39b AC |
6847 | |
6848 | when N_Type_Conversion => | |
6849 | Why_Not_Static (Expression (N)); | |
6850 | ||
23b86353 | 6851 | if not Is_Scalar_Type (Entity (Subtype_Mark (N))) |
edab6088 | 6852 | or else not Is_OK_Static_Subtype (Entity (Subtype_Mark (N))) |
fbf5a39b AC |
6853 | then |
6854 | Error_Msg_N | |
c8a3028c | 6855 | ("!static conversion requires static scalar subtype result " |
8fde064e | 6856 | & "(RM 4.9(9))", N); |
fbf5a39b AC |
6857 | end if; |
6858 | ||
8fde064e AC |
6859 | -- Unchecked type conversion |
6860 | ||
fbf5a39b AC |
6861 | when N_Unchecked_Type_Conversion => |
6862 | Error_Msg_N | |
c8a3028c | 6863 | ("!unchecked type conversion is never static (RM 4.9)", N); |
8fde064e AC |
6864 | |
6865 | -- All other cases, no reason to give | |
fbf5a39b AC |
6866 | |
6867 | when others => | |
6868 | null; | |
fbf5a39b AC |
6869 | end case; |
6870 | end Why_Not_Static; | |
6871 | ||
996ae0b0 | 6872 | end Sem_Eval; |