clang 8.0.0

RangeConstraintManager.cpp
Go to the documentation of this file.
1 //== RangeConstraintManager.cpp - Manage range constraints.------*- C++ -*--==//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines RangeConstraintManager, a class that tracks simple
11 // equality and inequality constraints on symbolic values of ProgramState.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "clang/StaticAnalyzer/Core/PathSensitive/APSIntType.h"
16 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
17 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
18 #include "clang/StaticAnalyzer/Core/PathSensitive/RangedConstraintManager.h"
19 #include "llvm/ADT/FoldingSet.h"
20 #include "llvm/ADT/ImmutableSet.h"
21 #include "llvm/Support/raw_ostream.h"
22
23 using namespace clang;
24 using namespace ento;
25
26 void RangeSet::IntersectInRange(BasicValueFactory &BV, Factory &F,
27 const llvm::APSInt &Lower, const llvm::APSInt &Upper,
28 PrimRangeSet &newRanges, PrimRangeSet::iterator &i,
29 PrimRangeSet::iterator &e) const {
30 // There are six cases for each range R in the set:
31 // 1. R is entirely before the intersection range.
32 // 2. R is entirely after the intersection range.
33 // 3. R contains the entire intersection range.
34 // 4. R starts before the intersection range and ends in the middle.
35 // 5. R starts in the middle of the intersection range and ends after it.
36 // 6. R is entirely contained in the intersection range.
37 // These correspond to each of the conditions below.
38 for (/* i = begin(), e = end() */; i != e; ++i) {
39 if (i->To() < Lower) {
40 continue;
41 }
42 if (i->From() > Upper) {
43 break;
44 }
45
46 if (i->Includes(Lower)) {
47 if (i->Includes(Upper)) {
48 newRanges =
49 F.add(newRanges, Range(BV.getValue(Lower), BV.getValue(Upper)));
50 break;
51 } else
52 newRanges = F.add(newRanges, Range(BV.getValue(Lower), i->To()));
53 } else {
54 if (i->Includes(Upper)) {
55 newRanges = F.add(newRanges, Range(i->From(), BV.getValue(Upper)));
56 break;
57 } else
58 newRanges = F.add(newRanges, *i);
59 }
60 }
61 }
62
63 const llvm::APSInt &RangeSet::getMinValue() const {
64 assert(!isEmpty());
65 return ranges.begin()->From();
66 }
67
68 bool RangeSet::pin(llvm::APSInt &Lower, llvm::APSInt &Upper) const {
69 // This function has nine cases, the cartesian product of range-testing
70 // both the upper and lower bounds against the symbol's type.
71 // Each case requires a different pinning operation.
72 // The function returns false if the described range is entirely outside
73 // the range of values for the associated symbol.
74 APSIntType Type(getMinValue());
75 APSIntType::RangeTestResultKind LowerTest = Type.testInRange(Lower, true);
76 APSIntType::RangeTestResultKind UpperTest = Type.testInRange(Upper, true);
77
78 switch (LowerTest) {
79 case APSIntType::RTR_Below:
80 switch (UpperTest) {
81 case APSIntType::RTR_Below:
82 // The entire range is outside the symbol's set of possible values.
83 // If this is a conventionally-ordered range, the state is infeasible.
84 if (Lower <= Upper)
85 return false;
86
87 // However, if the range wraps around, it spans all possible values.
88 Lower = Type.getMinValue();
89 Upper = Type.getMaxValue();
90 break;
91 case APSIntType::RTR_Within:
92 // The range starts below what's possible but ends within it. Pin.
93 Lower = Type.getMinValue();
94 Type.apply(Upper);
95 break;
96 case APSIntType::RTR_Above:
97 // The range spans all possible values for the symbol. Pin.
98 Lower = Type.getMinValue();
99 Upper = Type.getMaxValue();
100 break;
101 }
102 break;
103 case APSIntType::RTR_Within:
104 switch (UpperTest) {
105 case APSIntType::RTR_Below:
106 // The range wraps around, but all lower values are not possible.
107 Type.apply(Lower);
108 Upper = Type.getMaxValue();
109 break;
110 case APSIntType::RTR_Within:
111 // The range may or may not wrap around, but both limits are valid.
112 Type.apply(Lower);
113 Type.apply(Upper);
114 break;
115 case APSIntType::RTR_Above:
116 // The range starts within what's possible but ends above it. Pin.
117 Type.apply(Lower);
118 Upper = Type.getMaxValue();
119 break;
120 }
121 break;
122 case APSIntType::RTR_Above:
123 switch (UpperTest) {
124 case APSIntType::RTR_Below:
125 // The range wraps but is outside the symbol's set of possible values.
126 return false;
127 case APSIntType::RTR_Within:
128 // The range starts above what's possible but ends within it (wrap).
129 Lower = Type.getMinValue();
130 Type.apply(Upper);
131 break;
132 case APSIntType::RTR_Above:
133 // The entire range is outside the symbol's set of possible values.
134 // If this is a conventionally-ordered range, the state is infeasible.
135 if (Lower <= Upper)
136 return false;
137
138 // However, if the range wraps around, it spans all possible values.
139 Lower = Type.getMinValue();
140 Upper = Type.getMaxValue();
141 break;
142 }
143 break;
144 }
145
146 return true;
147 }
148
149 // Returns a set containing the values in the receiving set, intersected with
150 // the closed range [Lower, Upper]. Unlike the Range type, this range uses
151 // modular arithmetic, corresponding to the common treatment of C integer
152 // overflow. Thus, if the Lower bound is greater than the Upper bound, the
153 // range is taken to wrap around. This is equivalent to taking the
154 // intersection with the two ranges [Min, Upper] and [Lower, Max],
155 // or, alternatively, /removing/ all integers between Upper and Lower.
156 RangeSet RangeSet::Intersect(BasicValueFactory &BV, Factory &F,
157 llvm::APSInt Lower, llvm::APSInt Upper) const {
158 if (!pin(Lower, Upper))
159 return F.getEmptySet();
160
161 PrimRangeSet newRanges = F.getEmptySet();
162
163 PrimRangeSet::iterator i = begin(), e = end();
164 if (Lower <= Upper)
165 IntersectInRange(BV, F, Lower, Upper, newRanges, i, e);
166 else {
167 // The order of the next two statements is important!
168 // IntersectInRange() does not reset the iteration state for i and e.
169 // Therefore, the lower range most be handled first.
170 IntersectInRange(BV, F, BV.getMinValue(Upper), Upper, newRanges, i, e);
171 IntersectInRange(BV, F, Lower, BV.getMaxValue(Lower), newRanges, i, e);
172 }
173
174 return newRanges;
175 }
176
177 // Turn all [A, B] ranges to [-B, -A]. Ranges [MIN, B] are turned to range set
178 // [MIN, MIN] U [-B, MAX], when MIN and MAX are the minimal and the maximal
179 // signed values of the type.
180 RangeSet RangeSet::Negate(BasicValueFactory &BV, Factory &F) const {
181 PrimRangeSet newRanges = F.getEmptySet();
182
183 for (iterator i = begin(), e = end(); i != e; ++i) {
184 const llvm::APSInt &from = i->From(), &to = i->To();
185 const llvm::APSInt &newTo = (from.isMinSignedValue() ?
186 BV.getMaxValue(from) :
187 BV.getValue(- from));
188 if (to.isMaxSignedValue() && !newRanges.isEmpty() &&
189 newRanges.begin()->From().isMinSignedValue()) {
190 assert(newRanges.begin()->To().isMinSignedValue() &&
191 "Ranges should not overlap");
192 assert(!from.isMinSignedValue() && "Ranges should not overlap");
193 const llvm::APSInt &newFrom = newRanges.begin()->From();
194 newRanges =
195 F.add(F.remove(newRanges, *newRanges.begin()), Range(newFrom, newTo));
196 } else if (!to.isMinSignedValue()) {
197 const llvm::APSInt &newFrom = BV.getValue(- to);
198 newRanges = F.add(newRanges, Range(newFrom, newTo));
199 }
200 if (from.isMinSignedValue()) {
201 newRanges = F.add(newRanges, Range(BV.getMinValue(from),
202 BV.getMinValue(from)));
203 }
204 }
205
206 return newRanges;
207 }
208
209 void RangeSet::print(raw_ostream &os) const {
210 bool isFirst = true;
211 os << "{ ";
212 for (iterator i = begin(), e = end(); i != e; ++i) {
213 if (isFirst)
214 isFirst = false;
215 else
216 os << ", ";
217
218 os << '[' << i->From().toString(10) << ", " << i->To().toString(10)
219 << ']';
220 }
221 os << " }";
222 }
223
224 namespace {
225 class RangeConstraintManager : public RangedConstraintManager {
226 public:
227 RangeConstraintManager(SubEngine *SE, SValBuilder &SVB)
228 : RangedConstraintManager(SE, SVB) {}
229
230 //===------------------------------------------------------------------===//
231 // Implementation for interface from ConstraintManager.
232 //===------------------------------------------------------------------===//
233
234 bool canReasonAbout(SVal X) const override;
235
236 ConditionTruthVal checkNull(ProgramStateRef State, SymbolRef Sym) override;
237
238 const llvm::APSInt *getSymVal(ProgramStateRef State,
239 SymbolRef Sym) const override;
240
241 ProgramStateRef removeDeadBindings(ProgramStateRef State,
242 SymbolReaper &SymReaper) override;
243
244 void print(ProgramStateRef State, raw_ostream &Out, const char *nl,
245 const char *sep) override;
246
247 //===------------------------------------------------------------------===//
248 // Implementation for interface from RangedConstraintManager.
249 //===------------------------------------------------------------------===//
250
251 ProgramStateRef assumeSymNE(ProgramStateRef State, SymbolRef Sym,
252 const llvm::APSInt &V,
253 const llvm::APSInt &Adjustment) override;
254
255 ProgramStateRef assumeSymEQ(ProgramStateRef State, SymbolRef Sym,
256 const llvm::APSInt &V,
257 const llvm::APSInt &Adjustment) override;
258
259 ProgramStateRef assumeSymLT(ProgramStateRef State, SymbolRef Sym,
260 const llvm::APSInt &V,
261 const llvm::APSInt &Adjustment) override;
262
263 ProgramStateRef assumeSymGT(ProgramStateRef State, SymbolRef Sym,
264 const llvm::APSInt &V,
265 const llvm::APSInt &Adjustment) override;
266
267 ProgramStateRef assumeSymLE(ProgramStateRef State, SymbolRef Sym,
268 const llvm::APSInt &V,
269 const llvm::APSInt &Adjustment) override;
270
271 ProgramStateRef assumeSymGE(ProgramStateRef State, SymbolRef Sym,
272 const llvm::APSInt &V,
273 const llvm::APSInt &Adjustment) override;
274
275 ProgramStateRef assumeSymWithinInclusiveRange(
276 ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
277 const llvm::APSInt &To, const llvm::APSInt &Adjustment) override;
278
279 ProgramStateRef assumeSymOutsideInclusiveRange(
280 ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
281 const llvm::APSInt &To, const llvm::APSInt &Adjustment) override;
282
283 private:
284 RangeSet::Factory F;
285
286 RangeSet getRange(ProgramStateRef State, SymbolRef Sym);
287 const RangeSet* getRangeForMinusSymbol(ProgramStateRef State,
288 SymbolRef Sym);
289
290 RangeSet getSymLTRange(ProgramStateRef St, SymbolRef Sym,
291 const llvm::APSInt &Int,
292 const llvm::APSInt &Adjustment);
293 RangeSet getSymGTRange(ProgramStateRef St, SymbolRef Sym,
294 const llvm::APSInt &Int,
295 const llvm::APSInt &Adjustment);
296 RangeSet getSymLERange(ProgramStateRef St, SymbolRef Sym,
297 const llvm::APSInt &Int,
298 const llvm::APSInt &Adjustment);
299 RangeSet getSymLERange(llvm::function_ref<RangeSet()> RS,
300 const llvm::APSInt &Int,
301 const llvm::APSInt &Adjustment);
302 RangeSet getSymGERange(ProgramStateRef St, SymbolRef Sym,
303 const llvm::APSInt &Int,
304 const llvm::APSInt &Adjustment);
305
306 };
307
308 } // end anonymous namespace
309
310 std::unique_ptr<ConstraintManager>
311 ento::CreateRangeConstraintManager(ProgramStateManager &StMgr, SubEngine *Eng) {
312 return llvm::make_unique<RangeConstraintManager>(Eng, StMgr.getSValBuilder());
313 }
314
315 bool RangeConstraintManager::canReasonAbout(SVal X) const {
316 Optional<nonloc::SymbolVal> SymVal = X.getAs<nonloc::SymbolVal>();
317 if (SymVal && SymVal->isExpression()) {
318 const SymExpr *SE = SymVal->getSymbol();
319
320 if (const SymIntExpr *SIE = dyn_cast<SymIntExpr>(SE)) {
321 switch (SIE->getOpcode()) {
322 // We don't reason yet about bitwise-constraints on symbolic values.
323 case BO_And:
324 case BO_Or:
325 case BO_Xor:
326 return false;
327 // We don't reason yet about these arithmetic constraints on
328 // symbolic values.
329 case BO_Mul:
330 case BO_Div:
331 case BO_Rem:
332 case BO_Shl:
333 case BO_Shr:
334 return false;
335 // All other cases.
336 default:
337 return true;
338 }
339 }
340
341 if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(SE)) {
342 // FIXME: Handle <=> here.
343 if (BinaryOperator::isEqualityOp(SSE->getOpcode()) ||
344 BinaryOperator::isRelationalOp(SSE->getOpcode())) {
345 // We handle Loc <> Loc comparisons, but not (yet) NonLoc <> NonLoc.
346 // We've recently started producing Loc <> NonLoc comparisons (that
347 // result from casts of one of the operands between eg. intptr_t and
348 // void *), but we can't reason about them yet.
349 if (Loc::isLocType(SSE->getLHS()->getType())) {
350 return Loc::isLocType(SSE->getRHS()->getType());
351 }
352 }
353 }
354
355 return false;
356 }
357
358 return true;
359 }
360
361 ConditionTruthVal RangeConstraintManager::checkNull(ProgramStateRef State,
362 SymbolRef Sym) {
363 const RangeSet *Ranges = State->get<ConstraintRange>(Sym);
364
365 // If we don't have any information about this symbol, it's underconstrained.
366 if (!Ranges)
367 return ConditionTruthVal();
368
369 // If we have a concrete value, see if it's zero.
370 if (const llvm::APSInt *Value = Ranges->getConcreteValue())
371 return *Value == 0;
372
373 BasicValueFactory &BV = getBasicVals();
374 APSIntType IntType = BV.getAPSIntType(Sym->getType());
375 llvm::APSInt Zero = IntType.getZeroValue();
376
377 // Check if zero is in the set of possible values.
378 if (Ranges->Intersect(BV, F, Zero, Zero).isEmpty())
379 return false;
380
381 // Zero is a possible value, but it is not the /only/ possible value.
382 return ConditionTruthVal();
383 }
384
385 const llvm::APSInt *RangeConstraintManager::getSymVal(ProgramStateRef St,
386 SymbolRef Sym) const {
387 const ConstraintRangeTy::data_type *T = St->get<ConstraintRange>(Sym);
388 return T ? T->getConcreteValue() : nullptr;
389 }
390
391 /// Scan all symbols referenced by the constraints. If the symbol is not alive
392 /// as marked in LSymbols, mark it as dead in DSymbols.
393 ProgramStateRef
394 RangeConstraintManager::removeDeadBindings(ProgramStateRef State,
395 SymbolReaper &SymReaper) {
396 bool Changed = false;
397 ConstraintRangeTy CR = State->get<ConstraintRange>();
398 ConstraintRangeTy::Factory &CRFactory = State->get_context<ConstraintRange>();
399
400 for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
401 SymbolRef Sym = I.getKey();
402 if (SymReaper.isDead(Sym)) {
403 Changed = true;
404 CR = CRFactory.remove(CR, Sym);
405 }
406 }
407
408 return Changed ? State->set<ConstraintRange>(CR) : State;
409 }
410
411 /// Return a range set subtracting zero from \p Domain.
412 static RangeSet assumeNonZero(
413 BasicValueFactory &BV,
414 RangeSet::Factory &F,
415 SymbolRef Sym,
416 RangeSet Domain) {
417 APSIntType IntType = BV.getAPSIntType(Sym->getType());
418 return Domain.Intersect(BV, F, ++IntType.getZeroValue(),
419 --IntType.getZeroValue());
420 }
421
422 /// Apply implicit constraints for bitwise OR- and AND-.
423 /// For unsigned types, bitwise OR with a constant always returns
424 /// a value greater-or-equal than the constant, and bitwise AND
425 /// returns a value less-or-equal then the constant.
426 ///
427 /// Pattern matches the expression \p Sym against those rule,
428 /// and applies the required constraints.
429 /// \p Input Previously established expression range set
430 static RangeSet applyBitwiseConstraints(
431 BasicValueFactory &BV,
432 RangeSet::Factory &F,
433 RangeSet Input,
434 const SymIntExpr* SIE) {
435 QualType T = SIE->getType();
436 bool IsUnsigned = T->isUnsignedIntegerType();
437 const llvm::APSInt &RHS = SIE->getRHS();
438 const llvm::APSInt &Zero = BV.getAPSIntType(T).getZeroValue();
439 BinaryOperator::Opcode Operator = SIE->getOpcode();
440
441 // For unsigned types, the output of bitwise-or is bigger-or-equal than RHS.
442 if (Operator == BO_Or && IsUnsigned)
443 return Input.Intersect(BV, F, RHS, BV.getMaxValue(T));
444
445 // Bitwise-or with a non-zero constant is always non-zero.
446 if (Operator == BO_Or && RHS != Zero)
447 return assumeNonZero(BV, F, SIE, Input);
448
449 // For unsigned types, or positive RHS,
450 // bitwise-and output is always smaller-or-equal than RHS (assuming two's
451 // complement representation of signed types).
452 if (Operator == BO_And && (IsUnsigned || RHS >= Zero))
453 return Input.Intersect(BV, F, BV.getMinValue(T), RHS);
454
455 return Input;
456 }
457
458 RangeSet RangeConstraintManager::getRange(ProgramStateRef State,
459 SymbolRef Sym) {
460 if (ConstraintRangeTy::data_type *V = State->get<ConstraintRange>(Sym))
461 return *V;
462
463 BasicValueFactory &BV = getBasicVals();
464
465 // If Sym is a difference of symbols A - B, then maybe we have range set
466 // stored for B - A.
467 if (const RangeSet *R = getRangeForMinusSymbol(State, Sym))
468 return R->Negate(BV, F);
469
470 // Lazily generate a new RangeSet representing all possible values for the
471 // given symbol type.
472 QualType T = Sym->getType();
473
474 RangeSet Result(F, BV.getMinValue(T), BV.getMaxValue(T));
475
476 // References are known to be non-zero.
477 if (T->isReferenceType())
478 return assumeNonZero(BV, F, Sym, Result);
479
480 // Known constraints on ranges of bitwise expressions.
481 if (const SymIntExpr* SIE = dyn_cast<SymIntExpr>(Sym))
482 return applyBitwiseConstraints(BV, F, Result, SIE);
483
484 return Result;
485 }
486
487 // FIXME: Once SValBuilder supports unary minus, we should use SValBuilder to
488 // obtain the negated symbolic expression instead of constructing the
489 // symbol manually. This will allow us to support finding ranges of not
490 // only negated SymSymExpr-type expressions, but also of other, simpler
491 // expressions which we currently do not know how to negate.
492 const RangeSet*
493 RangeConstraintManager::getRangeForMinusSymbol(ProgramStateRef State,
494 SymbolRef Sym) {
495 if (const SymSymExpr *SSE = dyn_cast<SymSymExpr>(Sym)) {
496 if (SSE->getOpcode() == BO_Sub) {
497 QualType T = Sym->getType();
498 SymbolManager &SymMgr = State->getSymbolManager();
499 SymbolRef negSym = SymMgr.getSymSymExpr(SSE->getRHS(), BO_Sub,
500 SSE->getLHS(), T);
501 if (const RangeSet *negV = State->get<ConstraintRange>(negSym)) {
502 // Unsigned range set cannot be negated, unless it is [0, 0].
503 if ((negV->getConcreteValue() &&
504 (*negV->getConcreteValue() == 0)) ||
505 T->isSignedIntegerOrEnumerationType())
506 return negV;
507 }
508 }
509 }
510 return nullptr;
511 }
512
513 //===------------------------------------------------------------------------===
514 // assumeSymX methods: protected interface for RangeConstraintManager.
515 //===------------------------------------------------------------------------===/
516
517 // The syntax for ranges below is mathematical, using [x, y] for closed ranges
518 // and (x, y) for open ranges. These ranges are modular, corresponding with
519 // a common treatment of C integer overflow. This means that these methods
520 // do not have to worry about overflow; RangeSet::Intersect can handle such a
521 // "wraparound" range.
522 // As an example, the range [UINT_MAX-1, 3) contains five values: UINT_MAX-1,
523 // UINT_MAX, 0, 1, and 2.
524
525 ProgramStateRef
526 RangeConstraintManager::assumeSymNE(ProgramStateRef St, SymbolRef Sym,
527 const llvm::APSInt &Int,
528 const llvm::APSInt &Adjustment) {
529 // Before we do any real work, see if the value can even show up.
530 APSIntType AdjustmentType(Adjustment);
531 if (AdjustmentType.testInRange(Int, true) != APSIntType::RTR_Within)
532 return St;
533
534 llvm::APSInt Lower = AdjustmentType.convert(Int) - Adjustment;
535 llvm::APSInt Upper = Lower;
536 --Lower;
537 ++Upper;
538
539 // [Int-Adjustment+1, Int-Adjustment-1]
540 // Notice that the lower bound is greater than the upper bound.
541 RangeSet New = getRange(St, Sym).Intersect(getBasicVals(), F, Upper, Lower);
542 return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
543 }
544
545 ProgramStateRef
546 RangeConstraintManager::assumeSymEQ(ProgramStateRef St, SymbolRef Sym,
547 const llvm::APSInt &Int,
548 const llvm::APSInt &Adjustment) {
549 // Before we do any real work, see if the value can even show up.
550 APSIntType AdjustmentType(Adjustment);
551 if (AdjustmentType.testInRange(Int, true) != APSIntType::RTR_Within)
552 return nullptr;
553
554 // [Int-Adjustment, Int-Adjustment]
555 llvm::APSInt AdjInt = AdjustmentType.convert(Int) - Adjustment;
556 RangeSet New = getRange(St, Sym).Intersect(getBasicVals(), F, AdjInt, AdjInt);
557 return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
558 }
559
560 RangeSet RangeConstraintManager::getSymLTRange(ProgramStateRef St,
561 SymbolRef Sym,
562 const llvm::APSInt &Int,
563 const llvm::APSInt &Adjustment) {
564 // Before we do any real work, see if the value can even show up.
565 APSIntType AdjustmentType(Adjustment);
566 switch (AdjustmentType.testInRange(Int, true)) {
567 case APSIntType::RTR_Below:
568 return F.getEmptySet();
569 case APSIntType::RTR_Within:
570 break;
571 case APSIntType::RTR_Above:
572 return getRange(St, Sym);
573 }
574
575 // Special case for Int == Min. This is always false.
576 llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
577 llvm::APSInt Min = AdjustmentType.getMinValue();
578 if (ComparisonVal == Min)
579 return F.getEmptySet();
580
581 llvm::APSInt Lower = Min - Adjustment;
582 llvm::APSInt Upper = ComparisonVal - Adjustment;
583 --Upper;
584
585 return getRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
586 }
587
588 ProgramStateRef
589 RangeConstraintManager::assumeSymLT(ProgramStateRef St, SymbolRef Sym,
590 const llvm::APSInt &Int,
591 const llvm::APSInt &Adjustment) {
592 RangeSet New = getSymLTRange(St, Sym, Int, Adjustment);
593 return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
594 }
595
596 RangeSet RangeConstraintManager::getSymGTRange(ProgramStateRef St,
597 SymbolRef Sym,
598 const llvm::APSInt &Int,
599 const llvm::APSInt &Adjustment) {
600 // Before we do any real work, see if the value can even show up.
601 APSIntType AdjustmentType(Adjustment);
602 switch (AdjustmentType.testInRange(Int, true)) {
603 case APSIntType::RTR_Below:
604 return getRange(St, Sym);
605 case APSIntType::RTR_Within:
606 break;
607 case APSIntType::RTR_Above:
608 return F.getEmptySet();
609 }
610
611 // Special case for Int == Max. This is always false.
612 llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
613 llvm::APSInt Max = AdjustmentType.getMaxValue();
614 if (ComparisonVal == Max)
615 return F.getEmptySet();
616
617 llvm::APSInt Lower = ComparisonVal - Adjustment;
618 llvm::APSInt Upper = Max - Adjustment;
619 ++Lower;
620
621 return getRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
622 }
623
624 ProgramStateRef
625 RangeConstraintManager::assumeSymGT(ProgramStateRef St, SymbolRef Sym,
626 const llvm::APSInt &Int,
627 const llvm::APSInt &Adjustment) {
628 RangeSet New = getSymGTRange(St, Sym, Int, Adjustment);
629 return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
630 }
631
632 RangeSet RangeConstraintManager::getSymGERange(ProgramStateRef St,
633 SymbolRef Sym,
634 const llvm::APSInt &Int,
635 const llvm::APSInt &Adjustment) {
636 // Before we do any real work, see if the value can even show up.
637 APSIntType AdjustmentType(Adjustment);
638 switch (AdjustmentType.testInRange(Int, true)) {
639 case APSIntType::RTR_Below:
640 return getRange(St, Sym);
641 case APSIntType::RTR_Within:
642 break;
643 case APSIntType::RTR_Above:
644 return F.getEmptySet();
645 }
646
647 // Special case for Int == Min. This is always feasible.
648 llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
649 llvm::APSInt Min = AdjustmentType.getMinValue();
650 if (ComparisonVal == Min)
651 return getRange(St, Sym);
652
653 llvm::APSInt Max = AdjustmentType.getMaxValue();
654 llvm::APSInt Lower = ComparisonVal - Adjustment;
655 llvm::APSInt Upper = Max - Adjustment;
656
657 return getRange(St, Sym).Intersect(getBasicVals(), F, Lower, Upper);
658 }
659
660 ProgramStateRef
661 RangeConstraintManager::assumeSymGE(ProgramStateRef St, SymbolRef Sym,
662 const llvm::APSInt &Int,
663 const llvm::APSInt &Adjustment) {
664 RangeSet New = getSymGERange(St, Sym, Int, Adjustment);
665 return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
666 }
667
668 RangeSet RangeConstraintManager::getSymLERange(
669 llvm::function_ref<RangeSet()> RS,
670 const llvm::APSInt &Int,
671 const llvm::APSInt &Adjustment) {
672 // Before we do any real work, see if the value can even show up.
673 APSIntType AdjustmentType(Adjustment);
674 switch (AdjustmentType.testInRange(Int, true)) {
675 case APSIntType::RTR_Below:
676 return F.getEmptySet();
677 case APSIntType::RTR_Within:
678 break;
679 case APSIntType::RTR_Above:
680 return RS();
681 }
682
683 // Special case for Int == Max. This is always feasible.
684 llvm::APSInt ComparisonVal = AdjustmentType.convert(Int);
685 llvm::APSInt Max = AdjustmentType.getMaxValue();
686 if (ComparisonVal == Max)
687 return RS();
688
689 llvm::APSInt Min = AdjustmentType.getMinValue();
690 llvm::APSInt Lower = Min - Adjustment;
691 llvm::APSInt Upper = ComparisonVal - Adjustment;
692
693 return RS().Intersect(getBasicVals(), F, Lower, Upper);
694 }
695
696 RangeSet RangeConstraintManager::getSymLERange(ProgramStateRef St,
697 SymbolRef Sym,
698 const llvm::APSInt &Int,
699 const llvm::APSInt &Adjustment) {
700 return getSymLERange([&] { return getRange(St, Sym); }, Int, Adjustment);
701 }
702
703 ProgramStateRef
704 RangeConstraintManager::assumeSymLE(ProgramStateRef St, SymbolRef Sym,
705 const llvm::APSInt &Int,
706 const llvm::APSInt &Adjustment) {
707 RangeSet New = getSymLERange(St, Sym, Int, Adjustment);
708 return New.isEmpty() ? nullptr : St->set<ConstraintRange>(Sym, New);
709 }
710
711 ProgramStateRef RangeConstraintManager::assumeSymWithinInclusiveRange(
712 ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
713 const llvm::APSInt &To, const llvm::APSInt &Adjustment) {
714 RangeSet New = getSymGERange(State, Sym, From, Adjustment);
715 if (New.isEmpty())
716 return nullptr;
717 RangeSet Out = getSymLERange([&] { return New; }, To, Adjustment);
718 return Out.isEmpty() ? nullptr : State->set<ConstraintRange>(Sym, Out);
719 }
720
721 ProgramStateRef RangeConstraintManager::assumeSymOutsideInclusiveRange(
722 ProgramStateRef State, SymbolRef Sym, const llvm::APSInt &From,
723 const llvm::APSInt &To, const llvm::APSInt &Adjustment) {
724 RangeSet RangeLT = getSymLTRange(State, Sym, From, Adjustment);
725 RangeSet RangeGT = getSymGTRange(State, Sym, To, Adjustment);
726 RangeSet New(RangeLT.addRange(F, RangeGT));
727 return New.isEmpty() ? nullptr : State->set<ConstraintRange>(Sym, New);
728 }
729
730 //===------------------------------------------------------------------------===
731 // Pretty-printing.
732 //===------------------------------------------------------------------------===/
733
734 void RangeConstraintManager::print(ProgramStateRef St, raw_ostream &Out,
735 const char *nl, const char *sep) {
736
737 ConstraintRangeTy Ranges = St->get<ConstraintRange>();
738
739 if (Ranges.isEmpty()) {
740 Out << nl << sep << "Ranges are empty." << nl;
741 return;
742 }
743
744 Out << nl << sep << "Ranges of symbol values:";
745 for (ConstraintRangeTy::iterator I = Ranges.begin(), E = Ranges.end(); I != E;
746 ++I) {
747 Out << nl << ' ' << I.getKey() << " : ";
748 I.getData().print(Out);
749 }
750 Out << nl;
751 }
ento
clang::ento::SubEngine
Definition: SubEngine.h:47
clang::QualType
A (possibly-)qualified type.
Definition: Type.h:638
clang::ento::APSIntType::RTR_Below
Value is less than the minimum representable value.
Definition: APSIntType.h:78
clang::ento::SymbolReaper::isDead
bool isDead(SymbolRef sym)
Returns whether or not a symbol has been confirmed dead.
Definition: SymbolManager.h:614
RangedConstraintManager.h
clang::ento::SymbolRef
const SymExpr * SymbolRef
Definition: PathDiagnostic.h:59
clang::ento::CreateRangeConstraintManager
std::unique_ptr< ConstraintManager > CreateRangeConstraintManager(ProgramStateManager &statemgr, SubEngine *subengine)
Definition: RangeConstraintManager.cpp:311
clang::ento::ProgramStateRef
IntrusiveRefCntPtr< const ProgramState > ProgramStateRef
Definition: ProgramState_Fwd.h:38
clang::Type
The base class of the type hierarchy.
Definition: Type.h:1407
clang::ento::Range
A Range represents the closed range [from, to].
Definition: RangedConstraintManager.h:28
clang::ento::ConstraintRangeTy
llvm::ImmutableMap< SymbolRef, RangeSet > ConstraintRangeTy
Definition: RangedConstraintManager.h:129
Value
Value
Definition: UninitializedValues.cpp:102
clang::Type::isUnsignedIntegerType
bool isUnsignedIntegerType() const
Return true if this is an integer type that is unsigned, according to C99 6.2.5p6 [which returns true...
Definition: Type.cpp:1884
clang::ento::RangeSet
RangeSet contains a set of ranges.
Definition: RangedConstraintManager.h:64
clang::BinaryOperator::isEqualityOp
bool isEqualityOp() const
Definition: Expr.h:3375
clang::ento::BasicValueFactory
Definition: BasicValueFactory.h:107
clang::ento::SymExpr
Symbolic value.
Definition: SymExpr.h:30
llvm::Optional
Definition: LLVM.h:38
State
LineState State
Definition: UnwrappedLineFormatter.cpp:877
clang::ento::RangeSet::isEmpty
bool isEmpty() const
Definition: RangedConstraintManager.h:87
APSIntType.h
clang::Type::isReferenceType
bool isReferenceType() const
Definition: Type.h:6308
clang::ento::ConstraintRange
Definition: RangedConstraintManager.h:128
clang::ento::ProgramStateManager::getSValBuilder
SValBuilder & getSValBuilder()
Definition: ProgramState.h:542
clang::ento::RangeSet::Negate
RangeSet Negate(BasicValueFactory &BV, Factory &F) const
Definition: RangeConstraintManager.cpp:180
clang::ento::Loc::isLocType
static bool isLocType(QualType T)
Definition: SVals.h:327
clang::BinaryOperatorKind
BinaryOperatorKind
Definition: OperationKinds.h:26
clang::ento::RangeSet::Factory
PrimRangeSet::Factory Factory
Definition: RangedConstraintManager.h:70
clang::ento::APSIntType::RTR_Within
Value is representable using this type.
Definition: APSIntType.h:79
clang::ento::APSIntType
A record of the "type" of an APSInt, used for conversions.
Definition: APSIntType.h:20
clang::ento::SymIntExpr
Represents a symbolic expression like &#39;x&#39; + 3.
Definition: SymbolManager.h:333
clang::BinaryOperator::isRelationalOp
bool isRelationalOp() const
Definition: Expr.h:3372
clang::ento::APSIntType::getZeroValue
llvm::APSInt getZeroValue() const LLVM_READONLY
Returns an all-zero value for this type.
Definition: APSIntType.h:56
clang::ento::SymExpr::getType
virtual QualType getType() const =0
clang::ento::RangeSet::print
void print(raw_ostream &os) const
Definition: RangeConstraintManager.cpp:209
ProgramState.h
clang::ento::RangeSet::getConcreteValue
const llvm::APSInt * getConcreteValue() const
getConcreteValue - If a symbol is contrained to equal a specific integer constant then this method re...
Definition: RangedConstraintManager.h:100
assumeNonZero
static RangeSet assumeNonZero(BasicValueFactory &BV, RangeSet::Factory &F, SymbolRef Sym, RangeSet Domain)
Return a range set subtracting zero from Domain.
Definition: RangeConstraintManager.cpp:412
clang::ento::SVal::getAs
Optional< T > getAs() const
Convert to the specified SVal type, returning None if this SVal is not of the desired type...
Definition: SVals.h:112
clang::ento::RangeSet::end
iterator end() const
Definition: RangedConstraintManager.h:85
llvm::IntrusiveRefCntPtr
Definition: LLVM.h:45
clang::ento::SVal
SVal - This represents a symbolic expression, which can be either an L-value or an R-value...
Definition: SVals.h:76
clang::Type::isSignedIntegerOrEnumerationType
bool isSignedIntegerOrEnumerationType() const
Determines whether this is an integer type that is signed or an enumeration types whose underlying ty...
Definition: Type.cpp:1860
clang::ento::SymbolReaper
A class responsible for cleaning up unused symbols.
Definition: SymbolManager.h:549
clang::ento::ProgramStateManager
Definition: ProgramState.h:491
clang::ento::APSIntType::RTR_Above
Value is greater than the maximum representable value.
Definition: APSIntType.h:80
clang::ento::APSIntType::RangeTestResultKind
RangeTestResultKind
Used to classify whether a value is representable using this type.
Definition: APSIntType.h:77
clang
Dataflow Directional Tag Classes.
Definition: CFGReachabilityAnalysis.h:22
clang::ento::RangeSet::RangeSet
RangeSet(PrimRangeSet RS)
Definition: RangedConstraintManager.h:73
clang::ento::RangedConstraintManager
Definition: RangedConstraintManager.h:138
clang::ento::SValBuilder
Definition: SValBuilder.h:53
clang::ento::nonloc::SymbolVal
Represents symbolic expression that isn&#39;t a location.
Definition: SVals.h:347
clang::ento::BasicValueFactory::getMinValue
const llvm::APSInt & getMinValue(const llvm::APSInt &v)
Definition: BasicValueFactory.h:176
clang::ento::BasicValueFactory::getAPSIntType
APSIntType getAPSIntType(QualType T) const
Returns the type of the APSInt used to store values of the given QualType.
Definition: BasicValueFactory.h:142
clang::ento::RangeSet::Intersect
RangeSet Intersect(BasicValueFactory &BV, Factory &F, llvm::APSInt Lower, llvm::APSInt Upper) const
Definition: RangeConstraintManager.cpp:156
clang::ento::RangeSet::iterator
PrimRangeSet::iterator iterator
Definition: RangedConstraintManager.h:71
applyBitwiseConstraints
static RangeSet applyBitwiseConstraints(BasicValueFactory &BV, RangeSet::Factory &F, RangeSet Input, const SymIntExpr *SIE)
Apply implicit constraints for bitwise OR- and AND-.
Definition: RangeConstraintManager.cpp:430
X
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13954
clang::ento::BasicValueFactory::getMaxValue
const llvm::APSInt & getMaxValue(const llvm::APSInt &v)
Definition: BasicValueFactory.h:172
clang::ento::RangeSet::begin
iterator begin() const
Definition: RangedConstraintManager.h:84
ProgramStateTrait.h
clang::ento::ConditionTruthVal
Definition: ConstraintManager.h:39
clang::ento::SymSymExpr
Represents a symbolic expression like &#39;x&#39; + &#39;y&#39;.
Definition: SymbolManager.h:419