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SimpleSValBuilder.cpp
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1 // SimpleSValBuilder.cpp - A basic SValBuilder -----------------------*- 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 SimpleSValBuilder, a basic implementation of SValBuilder.
11 //
12 //===----------------------------------------------------------------------===//
13 
20 
21 using namespace clang;
22 using namespace ento;
23 
24 namespace {
25 class SimpleSValBuilder : public SValBuilder {
26 protected:
27  SVal dispatchCast(SVal val, QualType castTy) override;
28  SVal evalCastFromNonLoc(NonLoc val, QualType castTy) override;
29  SVal evalCastFromLoc(Loc val, QualType castTy) override;
30 
31 public:
32  SimpleSValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context,
33  ProgramStateManager &stateMgr)
34  : SValBuilder(alloc, context, stateMgr) {}
35  ~SimpleSValBuilder() override {}
36 
37  SVal evalMinus(NonLoc val) override;
38  SVal evalComplement(NonLoc val) override;
40  NonLoc lhs, NonLoc rhs, QualType resultTy) override;
42  Loc lhs, Loc rhs, QualType resultTy) override;
44  Loc lhs, NonLoc rhs, QualType resultTy) override;
45 
46  /// getKnownValue - evaluates a given SVal. If the SVal has only one possible
47  /// (integer) value, that value is returned. Otherwise, returns NULL.
48  const llvm::APSInt *getKnownValue(ProgramStateRef state, SVal V) override;
49 
50  /// Recursively descends into symbolic expressions and replaces symbols
51  /// with their known values (in the sense of the getKnownValue() method).
52  SVal simplifySVal(ProgramStateRef State, SVal V) override;
53 
54  SVal MakeSymIntVal(const SymExpr *LHS, BinaryOperator::Opcode op,
55  const llvm::APSInt &RHS, QualType resultTy);
56 };
57 } // end anonymous namespace
58 
59 SValBuilder *ento::createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc,
60  ASTContext &context,
61  ProgramStateManager &stateMgr) {
62  return new SimpleSValBuilder(alloc, context, stateMgr);
63 }
64 
65 //===----------------------------------------------------------------------===//
66 // Transfer function for Casts.
67 //===----------------------------------------------------------------------===//
68 
69 SVal SimpleSValBuilder::dispatchCast(SVal Val, QualType CastTy) {
70  assert(Val.getAs<Loc>() || Val.getAs<NonLoc>());
71  return Val.getAs<Loc>() ? evalCastFromLoc(Val.castAs<Loc>(), CastTy)
72  : evalCastFromNonLoc(Val.castAs<NonLoc>(), CastTy);
73 }
74 
75 SVal SimpleSValBuilder::evalCastFromNonLoc(NonLoc val, QualType castTy) {
76  bool isLocType = Loc::isLocType(castTy);
77  if (val.getAs<nonloc::PointerToMember>())
78  return val;
79 
81  if (isLocType)
82  return LI->getLoc();
83  // FIXME: Correctly support promotions/truncations.
84  unsigned castSize = Context.getIntWidth(castTy);
85  if (castSize == LI->getNumBits())
86  return val;
87  return makeLocAsInteger(LI->getLoc(), castSize);
88  }
89 
90  if (const SymExpr *se = val.getAsSymbolicExpression()) {
91  QualType T = Context.getCanonicalType(se->getType());
92  // If types are the same or both are integers, ignore the cast.
93  // FIXME: Remove this hack when we support symbolic truncation/extension.
94  // HACK: If both castTy and T are integers, ignore the cast. This is
95  // not a permanent solution. Eventually we want to precisely handle
96  // extension/truncation of symbolic integers. This prevents us from losing
97  // precision when we assign 'x = y' and 'y' is symbolic and x and y are
98  // different integer types.
99  if (haveSameType(T, castTy))
100  return val;
101 
102  if (!isLocType)
103  return makeNonLoc(se, T, castTy);
104  return UnknownVal();
105  }
106 
107  // If value is a non-integer constant, produce unknown.
108  if (!val.getAs<nonloc::ConcreteInt>())
109  return UnknownVal();
110 
111  // Handle casts to a boolean type.
112  if (castTy->isBooleanType()) {
113  bool b = val.castAs<nonloc::ConcreteInt>().getValue().getBoolValue();
114  return makeTruthVal(b, castTy);
115  }
116 
117  // Only handle casts from integers to integers - if val is an integer constant
118  // being cast to a non-integer type, produce unknown.
119  if (!isLocType && !castTy->isIntegralOrEnumerationType())
120  return UnknownVal();
121 
122  llvm::APSInt i = val.castAs<nonloc::ConcreteInt>().getValue();
123  BasicVals.getAPSIntType(castTy).apply(i);
124 
125  if (isLocType)
126  return makeIntLocVal(i);
127  else
128  return makeIntVal(i);
129 }
130 
131 SVal SimpleSValBuilder::evalCastFromLoc(Loc val, QualType castTy) {
132 
133  // Casts from pointers -> pointers, just return the lval.
134  //
135  // Casts from pointers -> references, just return the lval. These
136  // can be introduced by the frontend for corner cases, e.g
137  // casting from va_list* to __builtin_va_list&.
138  //
139  if (Loc::isLocType(castTy) || castTy->isReferenceType())
140  return val;
141 
142  // FIXME: Handle transparent unions where a value can be "transparently"
143  // lifted into a union type.
144  if (castTy->isUnionType())
145  return UnknownVal();
146 
147  // Casting a Loc to a bool will almost always be true,
148  // unless this is a weak function or a symbolic region.
149  if (castTy->isBooleanType()) {
150  switch (val.getSubKind()) {
151  case loc::MemRegionValKind: {
152  const MemRegion *R = val.castAs<loc::MemRegionVal>().getRegion();
153  if (const FunctionCodeRegion *FTR = dyn_cast<FunctionCodeRegion>(R))
154  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(FTR->getDecl()))
155  if (FD->isWeak())
156  // FIXME: Currently we are using an extent symbol here,
157  // because there are no generic region address metadata
158  // symbols to use, only content metadata.
159  return nonloc::SymbolVal(SymMgr.getExtentSymbol(FTR));
160 
161  if (const SymbolicRegion *SymR = R->getSymbolicBase())
162  return nonloc::SymbolVal(SymR->getSymbol());
163 
164  // FALL-THROUGH
165  LLVM_FALLTHROUGH;
166  }
167 
168  case loc::GotoLabelKind:
169  // Labels and non-symbolic memory regions are always true.
170  return makeTruthVal(true, castTy);
171  }
172  }
173 
174  if (castTy->isIntegralOrEnumerationType()) {
175  unsigned BitWidth = Context.getIntWidth(castTy);
176 
177  if (!val.getAs<loc::ConcreteInt>())
178  return makeLocAsInteger(val, BitWidth);
179 
180  llvm::APSInt i = val.castAs<loc::ConcreteInt>().getValue();
181  BasicVals.getAPSIntType(castTy).apply(i);
182  return makeIntVal(i);
183  }
184 
185  // All other cases: return 'UnknownVal'. This includes casting pointers
186  // to floats, which is probably badness it itself, but this is a good
187  // intermediate solution until we do something better.
188  return UnknownVal();
189 }
190 
191 //===----------------------------------------------------------------------===//
192 // Transfer function for unary operators.
193 //===----------------------------------------------------------------------===//
194 
195 SVal SimpleSValBuilder::evalMinus(NonLoc val) {
196  switch (val.getSubKind()) {
197  case nonloc::ConcreteIntKind:
198  return val.castAs<nonloc::ConcreteInt>().evalMinus(*this);
199  default:
200  return UnknownVal();
201  }
202 }
203 
204 SVal SimpleSValBuilder::evalComplement(NonLoc X) {
205  switch (X.getSubKind()) {
206  case nonloc::ConcreteIntKind:
207  return X.castAs<nonloc::ConcreteInt>().evalComplement(*this);
208  default:
209  return UnknownVal();
210  }
211 }
212 
213 //===----------------------------------------------------------------------===//
214 // Transfer function for binary operators.
215 //===----------------------------------------------------------------------===//
216 
217 SVal SimpleSValBuilder::MakeSymIntVal(const SymExpr *LHS,
219  const llvm::APSInt &RHS,
220  QualType resultTy) {
221  bool isIdempotent = false;
222 
223  // Check for a few special cases with known reductions first.
224  switch (op) {
225  default:
226  // We can't reduce this case; just treat it normally.
227  break;
228  case BO_Mul:
229  // a*0 and a*1
230  if (RHS == 0)
231  return makeIntVal(0, resultTy);
232  else if (RHS == 1)
233  isIdempotent = true;
234  break;
235  case BO_Div:
236  // a/0 and a/1
237  if (RHS == 0)
238  // This is also handled elsewhere.
239  return UndefinedVal();
240  else if (RHS == 1)
241  isIdempotent = true;
242  break;
243  case BO_Rem:
244  // a%0 and a%1
245  if (RHS == 0)
246  // This is also handled elsewhere.
247  return UndefinedVal();
248  else if (RHS == 1)
249  return makeIntVal(0, resultTy);
250  break;
251  case BO_Add:
252  case BO_Sub:
253  case BO_Shl:
254  case BO_Shr:
255  case BO_Xor:
256  // a+0, a-0, a<<0, a>>0, a^0
257  if (RHS == 0)
258  isIdempotent = true;
259  break;
260  case BO_And:
261  // a&0 and a&(~0)
262  if (RHS == 0)
263  return makeIntVal(0, resultTy);
264  else if (RHS.isAllOnesValue())
265  isIdempotent = true;
266  break;
267  case BO_Or:
268  // a|0 and a|(~0)
269  if (RHS == 0)
270  isIdempotent = true;
271  else if (RHS.isAllOnesValue()) {
272  const llvm::APSInt &Result = BasicVals.Convert(resultTy, RHS);
273  return nonloc::ConcreteInt(Result);
274  }
275  break;
276  }
277 
278  // Idempotent ops (like a*1) can still change the type of an expression.
279  // Wrap the LHS up in a NonLoc again and let evalCastFromNonLoc do the
280  // dirty work.
281  if (isIdempotent)
282  return evalCastFromNonLoc(nonloc::SymbolVal(LHS), resultTy);
283 
284  // If we reach this point, the expression cannot be simplified.
285  // Make a SymbolVal for the entire expression, after converting the RHS.
286  const llvm::APSInt *ConvertedRHS = &RHS;
288  // We're looking for a type big enough to compare the symbolic value
289  // with the given constant.
290  // FIXME: This is an approximation of Sema::UsualArithmeticConversions.
291  ASTContext &Ctx = getContext();
292  QualType SymbolType = LHS->getType();
293  uint64_t ValWidth = RHS.getBitWidth();
294  uint64_t TypeWidth = Ctx.getTypeSize(SymbolType);
295 
296  if (ValWidth < TypeWidth) {
297  // If the value is too small, extend it.
298  ConvertedRHS = &BasicVals.Convert(SymbolType, RHS);
299  } else if (ValWidth == TypeWidth) {
300  // If the value is signed but the symbol is unsigned, do the comparison
301  // in unsigned space. [C99 6.3.1.8]
302  // (For the opposite case, the value is already unsigned.)
303  if (RHS.isSigned() && !SymbolType->isSignedIntegerOrEnumerationType())
304  ConvertedRHS = &BasicVals.Convert(SymbolType, RHS);
305  }
306  } else
307  ConvertedRHS = &BasicVals.Convert(resultTy, RHS);
308 
309  return makeNonLoc(LHS, op, *ConvertedRHS, resultTy);
310 }
311 
312 // See if Sym is known to be a relation Rel with Bound.
314  llvm::APSInt Bound, ProgramStateRef State) {
315  SValBuilder &SVB = State->getStateManager().getSValBuilder();
316  SVal Result =
317  SVB.evalBinOpNN(State, Rel, nonloc::SymbolVal(Sym),
318  nonloc::ConcreteInt(Bound), SVB.getConditionType());
319  if (auto DV = Result.getAs<DefinedSVal>()) {
320  return !State->assume(*DV, false);
321  }
322  return false;
323 }
324 
325 // See if Sym is known to be within [min/4, max/4], where min and max
326 // are the bounds of the symbol's integral type. With such symbols,
327 // some manipulations can be performed without the risk of overflow.
328 // assume() doesn't cause infinite recursion because we should be dealing
329 // with simpler symbols on every recursive call.
332  SValBuilder &SVB = State->getStateManager().getSValBuilder();
334 
335  QualType T = Sym->getType();
336  assert(T->isSignedIntegerOrEnumerationType() &&
337  "This only works with signed integers!");
338  APSIntType AT = BV.getAPSIntType(T);
339 
340  llvm::APSInt Max = AT.getMaxValue() / AT.getValue(4), Min = -Max;
341  return isInRelation(BO_LE, Sym, Max, State) &&
342  isInRelation(BO_GE, Sym, Min, State);
343 }
344 
345 // Same for the concrete integers: see if I is within [min/4, max/4].
346 static bool isWithinConstantOverflowBounds(llvm::APSInt I) {
347  APSIntType AT(I);
348  assert(!AT.isUnsigned() &&
349  "This only works with signed integers!");
350 
351  llvm::APSInt Max = AT.getMaxValue() / AT.getValue(4), Min = -Max;
352  return (I <= Max) && (I >= -Max);
353 }
354 
355 static std::pair<SymbolRef, llvm::APSInt>
357  if (const auto *SymInt = dyn_cast<SymIntExpr>(Sym))
358  if (BinaryOperator::isAdditiveOp(SymInt->getOpcode()))
359  return std::make_pair(SymInt->getLHS(),
360  (SymInt->getOpcode() == BO_Add) ?
361  (SymInt->getRHS()) :
362  (-SymInt->getRHS()));
363 
364  // Fail to decompose: "reduce" the problem to the "$x + 0" case.
365  return std::make_pair(Sym, BV.getValue(0, Sym->getType()));
366 }
367 
368 // Simplify "(LSym + LInt) Op (RSym + RInt)" assuming all values are of the
369 // same signed integral type and no overflows occur (which should be checked
370 // by the caller).
373  SymbolRef LSym, llvm::APSInt LInt,
374  SymbolRef RSym, llvm::APSInt RInt) {
375  SValBuilder &SVB = State->getStateManager().getSValBuilder();
377  SymbolManager &SymMgr = SVB.getSymbolManager();
378 
379  QualType SymTy = LSym->getType();
380  assert(SymTy == RSym->getType() &&
381  "Symbols are not of the same type!");
382  assert(APSIntType(LInt) == BV.getAPSIntType(SymTy) &&
383  "Integers are not of the same type as symbols!");
384  assert(APSIntType(RInt) == BV.getAPSIntType(SymTy) &&
385  "Integers are not of the same type as symbols!");
386 
387  QualType ResultTy;
389  ResultTy = SVB.getConditionType();
390  else if (BinaryOperator::isAdditiveOp(Op))
391  ResultTy = SymTy;
392  else
393  llvm_unreachable("Operation not suitable for unchecked rearrangement!");
394 
395  // FIXME: Can we use assume() without getting into an infinite recursion?
396  if (LSym == RSym)
397  return SVB.evalBinOpNN(State, Op, nonloc::ConcreteInt(LInt),
398  nonloc::ConcreteInt(RInt), ResultTy)
399  .castAs<NonLoc>();
400 
401  SymbolRef ResultSym = nullptr;
402  BinaryOperator::Opcode ResultOp;
403  llvm::APSInt ResultInt;
405  // Prefer comparing to a non-negative number.
406  // FIXME: Maybe it'd be better to have consistency in
407  // "$x - $y" vs. "$y - $x" because those are solver's keys.
408  if (LInt > RInt) {
409  ResultSym = SymMgr.getSymSymExpr(RSym, BO_Sub, LSym, SymTy);
411  ResultInt = LInt - RInt; // Opposite order!
412  } else {
413  ResultSym = SymMgr.getSymSymExpr(LSym, BO_Sub, RSym, SymTy);
414  ResultOp = Op;
415  ResultInt = RInt - LInt; // Opposite order!
416  }
417  } else {
418  ResultSym = SymMgr.getSymSymExpr(LSym, Op, RSym, SymTy);
419  ResultInt = (Op == BO_Add) ? (LInt + RInt) : (LInt - RInt);
420  ResultOp = BO_Add;
421  // Bring back the cosmetic difference.
422  if (ResultInt < 0) {
423  ResultInt = -ResultInt;
424  ResultOp = BO_Sub;
425  } else if (ResultInt == 0) {
426  // Shortcut: Simplify "$x + 0" to "$x".
427  return nonloc::SymbolVal(ResultSym);
428  }
429  }
430  const llvm::APSInt &PersistentResultInt = BV.getValue(ResultInt);
431  return nonloc::SymbolVal(
432  SymMgr.getSymIntExpr(ResultSym, ResultOp, PersistentResultInt, ResultTy));
433 }
434 
435 // Rearrange if symbol type matches the result type and if the operator is a
436 // comparison operator, both symbol and constant must be within constant
437 // overflow bounds.
439  SymbolRef Sym, llvm::APSInt Int, QualType Ty) {
440  return Sym->getType() == Ty &&
442  (isWithinConstantOverflowBounds(Sym, State) &&
444 }
445 
448  NonLoc Rhs, QualType ResultTy) {
449  ProgramStateManager &StateMgr = State->getStateManager();
450  SValBuilder &SVB = StateMgr.getSValBuilder();
451 
452  // We expect everything to be of the same type - this type.
453  QualType SingleTy;
454 
455  auto &Opts =
457 
458  SymbolRef LSym = Lhs.getAsSymbol();
459  if (!LSym)
460  return None;
461 
462  // Always rearrange additive operations but rearrange comparisons only if
463  // option is set.
465  Opts.shouldAggressivelySimplifyRelationalComparison()) {
466  SingleTy = LSym->getType();
467  if (ResultTy != SVB.getConditionType())
468  return None;
469  // Initialize SingleTy later with a symbol's type.
470  } else if (BinaryOperator::isAdditiveOp(Op)) {
471  SingleTy = ResultTy;
472  if (LSym->getType() != SingleTy)
473  return None;
474  // Substracting unsigned integers is a nightmare.
475  if (!SingleTy->isSignedIntegerOrEnumerationType())
476  return None;
477  } else {
478  // Don't rearrange other operations.
479  return None;
480  }
481 
482  assert(!SingleTy.isNull() && "We should have figured out the type by now!");
483 
484  SymbolRef RSym = Rhs.getAsSymbol();
485  if (!RSym || RSym->getType() != SingleTy)
486  return None;
487 
488  BasicValueFactory &BV = State->getBasicVals();
489  llvm::APSInt LInt, RInt;
490  std::tie(LSym, LInt) = decomposeSymbol(LSym, BV);
491  std::tie(RSym, RInt) = decomposeSymbol(RSym, BV);
492  if (!shouldRearrange(State, Op, LSym, LInt, SingleTy) ||
493  !shouldRearrange(State, Op, RSym, RInt, SingleTy))
494  return None;
495 
496  // We know that no overflows can occur anymore.
497  return doRearrangeUnchecked(State, Op, LSym, LInt, RSym, RInt);
498 }
499 
500 SVal SimpleSValBuilder::evalBinOpNN(ProgramStateRef state,
502  NonLoc lhs, NonLoc rhs,
503  QualType resultTy) {
504  NonLoc InputLHS = lhs;
505  NonLoc InputRHS = rhs;
506 
507  // Handle trivial case where left-side and right-side are the same.
508  if (lhs == rhs)
509  switch (op) {
510  default:
511  break;
512  case BO_EQ:
513  case BO_LE:
514  case BO_GE:
515  return makeTruthVal(true, resultTy);
516  case BO_LT:
517  case BO_GT:
518  case BO_NE:
519  return makeTruthVal(false, resultTy);
520  case BO_Xor:
521  case BO_Sub:
522  if (resultTy->isIntegralOrEnumerationType())
523  return makeIntVal(0, resultTy);
524  return evalCastFromNonLoc(makeIntVal(0, /*Unsigned=*/false), resultTy);
525  case BO_Or:
526  case BO_And:
527  return evalCastFromNonLoc(lhs, resultTy);
528  }
529 
530  while (1) {
531  switch (lhs.getSubKind()) {
532  default:
533  return makeSymExprValNN(state, op, lhs, rhs, resultTy);
534  case nonloc::PointerToMemberKind: {
535  assert(rhs.getSubKind() == nonloc::PointerToMemberKind &&
536  "Both SVals should have pointer-to-member-type");
537  auto LPTM = lhs.castAs<nonloc::PointerToMember>(),
538  RPTM = rhs.castAs<nonloc::PointerToMember>();
539  auto LPTMD = LPTM.getPTMData(), RPTMD = RPTM.getPTMData();
540  switch (op) {
541  case BO_EQ:
542  return makeTruthVal(LPTMD == RPTMD, resultTy);
543  case BO_NE:
544  return makeTruthVal(LPTMD != RPTMD, resultTy);
545  default:
546  return UnknownVal();
547  }
548  }
549  case nonloc::LocAsIntegerKind: {
550  Loc lhsL = lhs.castAs<nonloc::LocAsInteger>().getLoc();
551  switch (rhs.getSubKind()) {
552  case nonloc::LocAsIntegerKind:
553  // FIXME: at the moment the implementation
554  // of modeling "pointers as integers" is not complete.
556  return UnknownVal();
557  return evalBinOpLL(state, op, lhsL,
559  resultTy);
560  case nonloc::ConcreteIntKind: {
561  // FIXME: at the moment the implementation
562  // of modeling "pointers as integers" is not complete.
564  return UnknownVal();
565  // Transform the integer into a location and compare.
566  // FIXME: This only makes sense for comparisons. If we want to, say,
567  // add 1 to a LocAsInteger, we'd better unpack the Loc and add to it,
568  // then pack it back into a LocAsInteger.
569  llvm::APSInt i = rhs.castAs<nonloc::ConcreteInt>().getValue();
570  BasicVals.getAPSIntType(Context.VoidPtrTy).apply(i);
571  return evalBinOpLL(state, op, lhsL, makeLoc(i), resultTy);
572  }
573  default:
574  switch (op) {
575  case BO_EQ:
576  return makeTruthVal(false, resultTy);
577  case BO_NE:
578  return makeTruthVal(true, resultTy);
579  default:
580  // This case also handles pointer arithmetic.
581  return makeSymExprValNN(state, op, InputLHS, InputRHS, resultTy);
582  }
583  }
584  }
585  case nonloc::ConcreteIntKind: {
586  llvm::APSInt LHSValue = lhs.castAs<nonloc::ConcreteInt>().getValue();
587 
588  // If we're dealing with two known constants, just perform the operation.
589  if (const llvm::APSInt *KnownRHSValue = getKnownValue(state, rhs)) {
590  llvm::APSInt RHSValue = *KnownRHSValue;
592  // We're looking for a type big enough to compare the two values.
593  // FIXME: This is not correct. char + short will result in a promotion
594  // to int. Unfortunately we have lost types by this point.
595  APSIntType CompareType = std::max(APSIntType(LHSValue),
596  APSIntType(RHSValue));
597  CompareType.apply(LHSValue);
598  CompareType.apply(RHSValue);
599  } else if (!BinaryOperator::isShiftOp(op)) {
600  APSIntType IntType = BasicVals.getAPSIntType(resultTy);
601  IntType.apply(LHSValue);
602  IntType.apply(RHSValue);
603  }
604 
605  const llvm::APSInt *Result =
606  BasicVals.evalAPSInt(op, LHSValue, RHSValue);
607  if (!Result)
608  return UndefinedVal();
609 
610  return nonloc::ConcreteInt(*Result);
611  }
612 
613  // Swap the left and right sides and flip the operator if doing so
614  // allows us to better reason about the expression (this is a form
615  // of expression canonicalization).
616  // While we're at it, catch some special cases for non-commutative ops.
617  switch (op) {
618  case BO_LT:
619  case BO_GT:
620  case BO_LE:
621  case BO_GE:
623  // FALL-THROUGH
624  case BO_EQ:
625  case BO_NE:
626  case BO_Add:
627  case BO_Mul:
628  case BO_And:
629  case BO_Xor:
630  case BO_Or:
631  std::swap(lhs, rhs);
632  continue;
633  case BO_Shr:
634  // (~0)>>a
635  if (LHSValue.isAllOnesValue() && LHSValue.isSigned())
636  return evalCastFromNonLoc(lhs, resultTy);
637  // FALL-THROUGH
638  case BO_Shl:
639  // 0<<a and 0>>a
640  if (LHSValue == 0)
641  return evalCastFromNonLoc(lhs, resultTy);
642  return makeSymExprValNN(state, op, InputLHS, InputRHS, resultTy);
643  default:
644  return makeSymExprValNN(state, op, InputLHS, InputRHS, resultTy);
645  }
646  }
647  case nonloc::SymbolValKind: {
648  // We only handle LHS as simple symbols or SymIntExprs.
649  SymbolRef Sym = lhs.castAs<nonloc::SymbolVal>().getSymbol();
650 
651  // LHS is a symbolic expression.
652  if (const SymIntExpr *symIntExpr = dyn_cast<SymIntExpr>(Sym)) {
653 
654  // Is this a logical not? (!x is represented as x == 0.)
655  if (op == BO_EQ && rhs.isZeroConstant()) {
656  // We know how to negate certain expressions. Simplify them here.
657 
658  BinaryOperator::Opcode opc = symIntExpr->getOpcode();
659  switch (opc) {
660  default:
661  // We don't know how to negate this operation.
662  // Just handle it as if it were a normal comparison to 0.
663  break;
664  case BO_LAnd:
665  case BO_LOr:
666  llvm_unreachable("Logical operators handled by branching logic.");
667  case BO_Assign:
668  case BO_MulAssign:
669  case BO_DivAssign:
670  case BO_RemAssign:
671  case BO_AddAssign:
672  case BO_SubAssign:
673  case BO_ShlAssign:
674  case BO_ShrAssign:
675  case BO_AndAssign:
676  case BO_XorAssign:
677  case BO_OrAssign:
678  case BO_Comma:
679  llvm_unreachable("'=' and ',' operators handled by ExprEngine.");
680  case BO_PtrMemD:
681  case BO_PtrMemI:
682  llvm_unreachable("Pointer arithmetic not handled here.");
683  case BO_LT:
684  case BO_GT:
685  case BO_LE:
686  case BO_GE:
687  case BO_EQ:
688  case BO_NE:
689  assert(resultTy->isBooleanType() ||
690  resultTy == getConditionType());
691  assert(symIntExpr->getType()->isBooleanType() ||
692  getContext().hasSameUnqualifiedType(symIntExpr->getType(),
693  getConditionType()));
694  // Negate the comparison and make a value.
696  return makeNonLoc(symIntExpr->getLHS(), opc,
697  symIntExpr->getRHS(), resultTy);
698  }
699  }
700 
701  // For now, only handle expressions whose RHS is a constant.
702  if (const llvm::APSInt *RHSValue = getKnownValue(state, rhs)) {
703  // If both the LHS and the current expression are additive,
704  // fold their constants and try again.
706  BinaryOperator::Opcode lop = symIntExpr->getOpcode();
707  if (BinaryOperator::isAdditiveOp(lop)) {
708  // Convert the two constants to a common type, then combine them.
709 
710  // resultTy may not be the best type to convert to, but it's
711  // probably the best choice in expressions with mixed type
712  // (such as x+1U+2LL). The rules for implicit conversions should
713  // choose a reasonable type to preserve the expression, and will
714  // at least match how the value is going to be used.
715  APSIntType IntType = BasicVals.getAPSIntType(resultTy);
716  const llvm::APSInt &first = IntType.convert(symIntExpr->getRHS());
717  const llvm::APSInt &second = IntType.convert(*RHSValue);
718 
719  const llvm::APSInt *newRHS;
720  if (lop == op)
721  newRHS = BasicVals.evalAPSInt(BO_Add, first, second);
722  else
723  newRHS = BasicVals.evalAPSInt(BO_Sub, first, second);
724 
725  assert(newRHS && "Invalid operation despite common type!");
726  rhs = nonloc::ConcreteInt(*newRHS);
727  lhs = nonloc::SymbolVal(symIntExpr->getLHS());
728  op = lop;
729  continue;
730  }
731  }
732 
733  // Otherwise, make a SymIntExpr out of the expression.
734  return MakeSymIntVal(symIntExpr, op, *RHSValue, resultTy);
735  }
736  }
737 
738  // Does the symbolic expression simplify to a constant?
739  // If so, "fold" the constant by setting 'lhs' to a ConcreteInt
740  // and try again.
741  SVal simplifiedLhs = simplifySVal(state, lhs);
742  if (simplifiedLhs != lhs)
743  if (auto simplifiedLhsAsNonLoc = simplifiedLhs.getAs<NonLoc>()) {
744  lhs = *simplifiedLhsAsNonLoc;
745  continue;
746  }
747 
748  // Is the RHS a constant?
749  if (const llvm::APSInt *RHSValue = getKnownValue(state, rhs))
750  return MakeSymIntVal(Sym, op, *RHSValue, resultTy);
751 
752  if (Optional<NonLoc> V = tryRearrange(state, op, lhs, rhs, resultTy))
753  return *V;
754 
755  // Give up -- this is not a symbolic expression we can handle.
756  return makeSymExprValNN(state, op, InputLHS, InputRHS, resultTy);
757  }
758  }
759  }
760 }
761 
763  const FieldRegion *RightFR,
765  QualType resultTy,
766  SimpleSValBuilder &SVB) {
767  // Only comparisons are meaningful here!
769  return UnknownVal();
770 
771  // Next, see if the two FRs have the same super-region.
772  // FIXME: This doesn't handle casts yet, and simply stripping the casts
773  // doesn't help.
774  if (LeftFR->getSuperRegion() != RightFR->getSuperRegion())
775  return UnknownVal();
776 
777  const FieldDecl *LeftFD = LeftFR->getDecl();
778  const FieldDecl *RightFD = RightFR->getDecl();
779  const RecordDecl *RD = LeftFD->getParent();
780 
781  // Make sure the two FRs are from the same kind of record. Just in case!
782  // FIXME: This is probably where inheritance would be a problem.
783  if (RD != RightFD->getParent())
784  return UnknownVal();
785 
786  // We know for sure that the two fields are not the same, since that
787  // would have given us the same SVal.
788  if (op == BO_EQ)
789  return SVB.makeTruthVal(false, resultTy);
790  if (op == BO_NE)
791  return SVB.makeTruthVal(true, resultTy);
792 
793  // Iterate through the fields and see which one comes first.
794  // [C99 6.7.2.1.13] "Within a structure object, the non-bit-field
795  // members and the units in which bit-fields reside have addresses that
796  // increase in the order in which they are declared."
797  bool leftFirst = (op == BO_LT || op == BO_LE);
798  for (const auto *I : RD->fields()) {
799  if (I == LeftFD)
800  return SVB.makeTruthVal(leftFirst, resultTy);
801  if (I == RightFD)
802  return SVB.makeTruthVal(!leftFirst, resultTy);
803  }
804 
805  llvm_unreachable("Fields not found in parent record's definition");
806 }
807 
808 // FIXME: all this logic will change if/when we have MemRegion::getLocation().
809 SVal SimpleSValBuilder::evalBinOpLL(ProgramStateRef state,
811  Loc lhs, Loc rhs,
812  QualType resultTy) {
813  // Only comparisons and subtractions are valid operations on two pointers.
814  // See [C99 6.5.5 through 6.5.14] or [C++0x 5.6 through 5.15].
815  // However, if a pointer is casted to an integer, evalBinOpNN may end up
816  // calling this function with another operation (PR7527). We don't attempt to
817  // model this for now, but it could be useful, particularly when the
818  // "location" is actually an integer value that's been passed through a void*.
819  if (!(BinaryOperator::isComparisonOp(op) || op == BO_Sub))
820  return UnknownVal();
821 
822  // Special cases for when both sides are identical.
823  if (lhs == rhs) {
824  switch (op) {
825  default:
826  llvm_unreachable("Unimplemented operation for two identical values");
827  case BO_Sub:
828  return makeZeroVal(resultTy);
829  case BO_EQ:
830  case BO_LE:
831  case BO_GE:
832  return makeTruthVal(true, resultTy);
833  case BO_NE:
834  case BO_LT:
835  case BO_GT:
836  return makeTruthVal(false, resultTy);
837  }
838  }
839 
840  switch (lhs.getSubKind()) {
841  default:
842  llvm_unreachable("Ordering not implemented for this Loc.");
843 
844  case loc::GotoLabelKind:
845  // The only thing we know about labels is that they're non-null.
846  if (rhs.isZeroConstant()) {
847  switch (op) {
848  default:
849  break;
850  case BO_Sub:
851  return evalCastFromLoc(lhs, resultTy);
852  case BO_EQ:
853  case BO_LE:
854  case BO_LT:
855  return makeTruthVal(false, resultTy);
856  case BO_NE:
857  case BO_GT:
858  case BO_GE:
859  return makeTruthVal(true, resultTy);
860  }
861  }
862  // There may be two labels for the same location, and a function region may
863  // have the same address as a label at the start of the function (depending
864  // on the ABI).
865  // FIXME: we can probably do a comparison against other MemRegions, though.
866  // FIXME: is there a way to tell if two labels refer to the same location?
867  return UnknownVal();
868 
869  case loc::ConcreteIntKind: {
870  // If one of the operands is a symbol and the other is a constant,
871  // build an expression for use by the constraint manager.
872  if (SymbolRef rSym = rhs.getAsLocSymbol()) {
873  // We can only build expressions with symbols on the left,
874  // so we need a reversible operator.
875  if (!BinaryOperator::isComparisonOp(op) || op == BO_Cmp)
876  return UnknownVal();
877 
878  const llvm::APSInt &lVal = lhs.castAs<loc::ConcreteInt>().getValue();
880  return makeNonLoc(rSym, op, lVal, resultTy);
881  }
882 
883  // If both operands are constants, just perform the operation.
885  SVal ResultVal =
886  lhs.castAs<loc::ConcreteInt>().evalBinOp(BasicVals, op, *rInt);
887  if (Optional<NonLoc> Result = ResultVal.getAs<NonLoc>())
888  return evalCastFromNonLoc(*Result, resultTy);
889 
890  assert(!ResultVal.getAs<Loc>() && "Loc-Loc ops should not produce Locs");
891  return UnknownVal();
892  }
893 
894  // Special case comparisons against NULL.
895  // This must come after the test if the RHS is a symbol, which is used to
896  // build constraints. The address of any non-symbolic region is guaranteed
897  // to be non-NULL, as is any label.
898  assert(rhs.getAs<loc::MemRegionVal>() || rhs.getAs<loc::GotoLabel>());
899  if (lhs.isZeroConstant()) {
900  switch (op) {
901  default:
902  break;
903  case BO_EQ:
904  case BO_GT:
905  case BO_GE:
906  return makeTruthVal(false, resultTy);
907  case BO_NE:
908  case BO_LT:
909  case BO_LE:
910  return makeTruthVal(true, resultTy);
911  }
912  }
913 
914  // Comparing an arbitrary integer to a region or label address is
915  // completely unknowable.
916  return UnknownVal();
917  }
918  case loc::MemRegionValKind: {
920  // If one of the operands is a symbol and the other is a constant,
921  // build an expression for use by the constraint manager.
922  if (SymbolRef lSym = lhs.getAsLocSymbol(true)) {
924  return MakeSymIntVal(lSym, op, rInt->getValue(), resultTy);
925  return UnknownVal();
926  }
927  // Special case comparisons to NULL.
928  // This must come after the test if the LHS is a symbol, which is used to
929  // build constraints. The address of any non-symbolic region is guaranteed
930  // to be non-NULL.
931  if (rInt->isZeroConstant()) {
932  if (op == BO_Sub)
933  return evalCastFromLoc(lhs, resultTy);
934 
936  QualType boolType = getContext().BoolTy;
937  NonLoc l = evalCastFromLoc(lhs, boolType).castAs<NonLoc>();
938  NonLoc r = makeTruthVal(false, boolType).castAs<NonLoc>();
939  return evalBinOpNN(state, op, l, r, resultTy);
940  }
941  }
942 
943  // Comparing a region to an arbitrary integer is completely unknowable.
944  return UnknownVal();
945  }
946 
947  // Get both values as regions, if possible.
948  const MemRegion *LeftMR = lhs.getAsRegion();
949  assert(LeftMR && "MemRegionValKind SVal doesn't have a region!");
950 
951  const MemRegion *RightMR = rhs.getAsRegion();
952  if (!RightMR)
953  // The RHS is probably a label, which in theory could address a region.
954  // FIXME: we can probably make a more useful statement about non-code
955  // regions, though.
956  return UnknownVal();
957 
958  const MemRegion *LeftBase = LeftMR->getBaseRegion();
959  const MemRegion *RightBase = RightMR->getBaseRegion();
960  const MemSpaceRegion *LeftMS = LeftBase->getMemorySpace();
961  const MemSpaceRegion *RightMS = RightBase->getMemorySpace();
962  const MemSpaceRegion *UnknownMS = MemMgr.getUnknownRegion();
963 
964  // If the two regions are from different known memory spaces they cannot be
965  // equal. Also, assume that no symbolic region (whose memory space is
966  // unknown) is on the stack.
967  if (LeftMS != RightMS &&
968  ((LeftMS != UnknownMS && RightMS != UnknownMS) ||
969  (isa<StackSpaceRegion>(LeftMS) || isa<StackSpaceRegion>(RightMS)))) {
970  switch (op) {
971  default:
972  return UnknownVal();
973  case BO_EQ:
974  return makeTruthVal(false, resultTy);
975  case BO_NE:
976  return makeTruthVal(true, resultTy);
977  }
978  }
979 
980  // If both values wrap regions, see if they're from different base regions.
981  // Note, heap base symbolic regions are assumed to not alias with
982  // each other; for example, we assume that malloc returns different address
983  // on each invocation.
984  // FIXME: ObjC object pointers always reside on the heap, but currently
985  // we treat their memory space as unknown, because symbolic pointers
986  // to ObjC objects may alias. There should be a way to construct
987  // possibly-aliasing heap-based regions. For instance, MacOSXApiChecker
988  // guesses memory space for ObjC object pointers manually instead of
989  // relying on us.
990  if (LeftBase != RightBase &&
991  ((!isa<SymbolicRegion>(LeftBase) && !isa<SymbolicRegion>(RightBase)) ||
992  (isa<HeapSpaceRegion>(LeftMS) || isa<HeapSpaceRegion>(RightMS))) ){
993  switch (op) {
994  default:
995  return UnknownVal();
996  case BO_EQ:
997  return makeTruthVal(false, resultTy);
998  case BO_NE:
999  return makeTruthVal(true, resultTy);
1000  }
1001  }
1002 
1003  // Handle special cases for when both regions are element regions.
1004  const ElementRegion *RightER = dyn_cast<ElementRegion>(RightMR);
1005  const ElementRegion *LeftER = dyn_cast<ElementRegion>(LeftMR);
1006  if (RightER && LeftER) {
1007  // Next, see if the two ERs have the same super-region and matching types.
1008  // FIXME: This should do something useful even if the types don't match,
1009  // though if both indexes are constant the RegionRawOffset path will
1010  // give the correct answer.
1011  if (LeftER->getSuperRegion() == RightER->getSuperRegion() &&
1012  LeftER->getElementType() == RightER->getElementType()) {
1013  // Get the left index and cast it to the correct type.
1014  // If the index is unknown or undefined, bail out here.
1015  SVal LeftIndexVal = LeftER->getIndex();
1016  Optional<NonLoc> LeftIndex = LeftIndexVal.getAs<NonLoc>();
1017  if (!LeftIndex)
1018  return UnknownVal();
1019  LeftIndexVal = evalCastFromNonLoc(*LeftIndex, ArrayIndexTy);
1020  LeftIndex = LeftIndexVal.getAs<NonLoc>();
1021  if (!LeftIndex)
1022  return UnknownVal();
1023 
1024  // Do the same for the right index.
1025  SVal RightIndexVal = RightER->getIndex();
1026  Optional<NonLoc> RightIndex = RightIndexVal.getAs<NonLoc>();
1027  if (!RightIndex)
1028  return UnknownVal();
1029  RightIndexVal = evalCastFromNonLoc(*RightIndex, ArrayIndexTy);
1030  RightIndex = RightIndexVal.getAs<NonLoc>();
1031  if (!RightIndex)
1032  return UnknownVal();
1033 
1034  // Actually perform the operation.
1035  // evalBinOpNN expects the two indexes to already be the right type.
1036  return evalBinOpNN(state, op, *LeftIndex, *RightIndex, resultTy);
1037  }
1038  }
1039 
1040  // Special handling of the FieldRegions, even with symbolic offsets.
1041  const FieldRegion *RightFR = dyn_cast<FieldRegion>(RightMR);
1042  const FieldRegion *LeftFR = dyn_cast<FieldRegion>(LeftMR);
1043  if (RightFR && LeftFR) {
1044  SVal R = evalBinOpFieldRegionFieldRegion(LeftFR, RightFR, op, resultTy,
1045  *this);
1046  if (!R.isUnknown())
1047  return R;
1048  }
1049 
1050  // Compare the regions using the raw offsets.
1051  RegionOffset LeftOffset = LeftMR->getAsOffset();
1052  RegionOffset RightOffset = RightMR->getAsOffset();
1053 
1054  if (LeftOffset.getRegion() != nullptr &&
1055  LeftOffset.getRegion() == RightOffset.getRegion() &&
1056  !LeftOffset.hasSymbolicOffset() && !RightOffset.hasSymbolicOffset()) {
1057  int64_t left = LeftOffset.getOffset();
1058  int64_t right = RightOffset.getOffset();
1059 
1060  switch (op) {
1061  default:
1062  return UnknownVal();
1063  case BO_LT:
1064  return makeTruthVal(left < right, resultTy);
1065  case BO_GT:
1066  return makeTruthVal(left > right, resultTy);
1067  case BO_LE:
1068  return makeTruthVal(left <= right, resultTy);
1069  case BO_GE:
1070  return makeTruthVal(left >= right, resultTy);
1071  case BO_EQ:
1072  return makeTruthVal(left == right, resultTy);
1073  case BO_NE:
1074  return makeTruthVal(left != right, resultTy);
1075  }
1076  }
1077 
1078  // At this point we're not going to get a good answer, but we can try
1079  // conjuring an expression instead.
1080  SymbolRef LHSSym = lhs.getAsLocSymbol();
1081  SymbolRef RHSSym = rhs.getAsLocSymbol();
1082  if (LHSSym && RHSSym)
1083  return makeNonLoc(LHSSym, op, RHSSym, resultTy);
1084 
1085  // If we get here, we have no way of comparing the regions.
1086  return UnknownVal();
1087  }
1088  }
1089 }
1090 
1091 SVal SimpleSValBuilder::evalBinOpLN(ProgramStateRef state,
1093  Loc lhs, NonLoc rhs, QualType resultTy) {
1094  if (op >= BO_PtrMemD && op <= BO_PtrMemI) {
1095  if (auto PTMSV = rhs.getAs<nonloc::PointerToMember>()) {
1096  if (PTMSV->isNullMemberPointer())
1097  return UndefinedVal();
1098  if (const FieldDecl *FD = PTMSV->getDeclAs<FieldDecl>()) {
1099  SVal Result = lhs;
1100 
1101  for (const auto &I : *PTMSV)
1102  Result = StateMgr.getStoreManager().evalDerivedToBase(
1103  Result, I->getType(),I->isVirtual());
1104  return state->getLValue(FD, Result);
1105  }
1106  }
1107 
1108  return rhs;
1109  }
1110 
1111  assert(!BinaryOperator::isComparisonOp(op) &&
1112  "arguments to comparison ops must be of the same type");
1113 
1114  // Special case: rhs is a zero constant.
1115  if (rhs.isZeroConstant())
1116  return lhs;
1117 
1118  // Perserve the null pointer so that it can be found by the DerefChecker.
1119  if (lhs.isZeroConstant())
1120  return lhs;
1121 
1122  // We are dealing with pointer arithmetic.
1123 
1124  // Handle pointer arithmetic on constant values.
1126  if (Optional<loc::ConcreteInt> lhsInt = lhs.getAs<loc::ConcreteInt>()) {
1127  const llvm::APSInt &leftI = lhsInt->getValue();
1128  assert(leftI.isUnsigned());
1129  llvm::APSInt rightI(rhsInt->getValue(), /* isUnsigned */ true);
1130 
1131  // Convert the bitwidth of rightI. This should deal with overflow
1132  // since we are dealing with concrete values.
1133  rightI = rightI.extOrTrunc(leftI.getBitWidth());
1134 
1135  // Offset the increment by the pointer size.
1136  llvm::APSInt Multiplicand(rightI.getBitWidth(), /* isUnsigned */ true);
1137  QualType pointeeType = resultTy->getPointeeType();
1138  Multiplicand = getContext().getTypeSizeInChars(pointeeType).getQuantity();
1139  rightI *= Multiplicand;
1140 
1141  // Compute the adjusted pointer.
1142  switch (op) {
1143  case BO_Add:
1144  rightI = leftI + rightI;
1145  break;
1146  case BO_Sub:
1147  rightI = leftI - rightI;
1148  break;
1149  default:
1150  llvm_unreachable("Invalid pointer arithmetic operation");
1151  }
1152  return loc::ConcreteInt(getBasicValueFactory().getValue(rightI));
1153  }
1154  }
1155 
1156  // Handle cases where 'lhs' is a region.
1157  if (const MemRegion *region = lhs.getAsRegion()) {
1158  rhs = convertToArrayIndex(rhs).castAs<NonLoc>();
1159  SVal index = UnknownVal();
1160  const SubRegion *superR = nullptr;
1161  // We need to know the type of the pointer in order to add an integer to it.
1162  // Depending on the type, different amount of bytes is added.
1163  QualType elementType;
1164 
1165  if (const ElementRegion *elemReg = dyn_cast<ElementRegion>(region)) {
1166  assert(op == BO_Add || op == BO_Sub);
1167  index = evalBinOpNN(state, op, elemReg->getIndex(), rhs,
1168  getArrayIndexType());
1169  superR = cast<SubRegion>(elemReg->getSuperRegion());
1170  elementType = elemReg->getElementType();
1171  }
1172  else if (isa<SubRegion>(region)) {
1173  assert(op == BO_Add || op == BO_Sub);
1174  index = (op == BO_Add) ? rhs : evalMinus(rhs);
1175  superR = cast<SubRegion>(region);
1176  // TODO: Is this actually reliable? Maybe improving our MemRegion
1177  // hierarchy to provide typed regions for all non-void pointers would be
1178  // better. For instance, we cannot extend this towards LocAsInteger
1179  // operations, where result type of the expression is integer.
1180  if (resultTy->isAnyPointerType())
1181  elementType = resultTy->getPointeeType();
1182  }
1183 
1184  // Represent arithmetic on void pointers as arithmetic on char pointers.
1185  // It is fine when a TypedValueRegion of char value type represents
1186  // a void pointer. Note that arithmetic on void pointers is a GCC extension.
1187  if (elementType->isVoidType())
1188  elementType = getContext().CharTy;
1189 
1190  if (Optional<NonLoc> indexV = index.getAs<NonLoc>()) {
1191  return loc::MemRegionVal(MemMgr.getElementRegion(elementType, *indexV,
1192  superR, getContext()));
1193  }
1194  }
1195  return UnknownVal();
1196 }
1197 
1198 const llvm::APSInt *SimpleSValBuilder::getKnownValue(ProgramStateRef state,
1199  SVal V) {
1200  if (V.isUnknownOrUndef())
1201  return nullptr;
1202 
1204  return &X->getValue();
1205 
1207  return &X->getValue();
1208 
1209  if (SymbolRef Sym = V.getAsSymbol())
1210  return state->getConstraintManager().getSymVal(state, Sym);
1211 
1212  // FIXME: Add support for SymExprs.
1213  return nullptr;
1214 }
1215 
1216 SVal SimpleSValBuilder::simplifySVal(ProgramStateRef State, SVal V) {
1217  // For now, this function tries to constant-fold symbols inside a
1218  // nonloc::SymbolVal, and does nothing else. More simplifications should
1219  // be possible, such as constant-folding an index in an ElementRegion.
1220 
1221  class Simplifier : public FullSValVisitor<Simplifier, SVal> {
1223  SValBuilder &SVB;
1224 
1225  public:
1226  Simplifier(ProgramStateRef State)
1227  : State(State), SVB(State->getStateManager().getSValBuilder()) {}
1228 
1229  SVal VisitSymbolData(const SymbolData *S) {
1230  if (const llvm::APSInt *I =
1231  SVB.getKnownValue(State, nonloc::SymbolVal(S)))
1232  return Loc::isLocType(S->getType()) ? (SVal)SVB.makeIntLocVal(*I)
1233  : (SVal)SVB.makeIntVal(*I);
1234  return Loc::isLocType(S->getType()) ? (SVal)SVB.makeLoc(S)
1235  : nonloc::SymbolVal(S);
1236  }
1237 
1238  // TODO: Support SymbolCast. Support IntSymExpr when/if we actually
1239  // start producing them.
1240 
1241  SVal VisitSymIntExpr(const SymIntExpr *S) {
1242  SVal LHS = Visit(S->getLHS());
1243  SVal RHS;
1244  // By looking at the APSInt in the right-hand side of S, we cannot
1245  // figure out if it should be treated as a Loc or as a NonLoc.
1246  // So make our guess by recalling that we cannot multiply pointers
1247  // or compare a pointer to an integer.
1248  if (Loc::isLocType(S->getLHS()->getType()) &&
1250  // The usual conversion of $sym to &SymRegion{$sym}, as they have
1251  // the same meaning for Loc-type symbols, but the latter form
1252  // is preferred in SVal computations for being Loc itself.
1253  if (SymbolRef Sym = LHS.getAsSymbol()) {
1254  assert(Loc::isLocType(Sym->getType()));
1255  LHS = SVB.makeLoc(Sym);
1256  }
1257  RHS = SVB.makeIntLocVal(S->getRHS());
1258  } else {
1259  RHS = SVB.makeIntVal(S->getRHS());
1260  }
1261  return SVB.evalBinOp(State, S->getOpcode(), LHS, RHS, S->getType());
1262  }
1263 
1264  SVal VisitSymSymExpr(const SymSymExpr *S) {
1265  SVal LHS = Visit(S->getLHS());
1266  SVal RHS = Visit(S->getRHS());
1267  return SVB.evalBinOp(State, S->getOpcode(), LHS, RHS, S->getType());
1268  }
1269 
1270  SVal VisitSymExpr(SymbolRef S) { return nonloc::SymbolVal(S); }
1271 
1272  SVal VisitMemRegion(const MemRegion *R) { return loc::MemRegionVal(R); }
1273 
1274  SVal VisitNonLocSymbolVal(nonloc::SymbolVal V) {
1275  // Simplification is much more costly than computing complexity.
1276  // For high complexity, it may be not worth it.
1277  if (V.getSymbol()->computeComplexity() > 100)
1278  return V;
1279  return Visit(V.getSymbol());
1280  }
1281 
1282  SVal VisitSVal(SVal V) { return V; }
1283  };
1284 
1285  return Simplifier(State).Visit(V);
1286 }
Represents a function declaration or definition.
Definition: Decl.h:1714
nonloc::ConcreteInt makeIntVal(const IntegerLiteral *integer)
Definition: SValBuilder.h:279
SymbolManager & getSymbolManager()
Definition: SValBuilder.h:172
CanQualType VoidPtrTy
Definition: ASTContext.h:1014
A (possibly-)qualified type.
Definition: Type.h:654
MemRegion - The root abstract class for all memory regions.
Definition: MemRegion.h:94
SValBuilder * createSimpleSValBuilder(llvm::BumpPtrAllocator &alloc, ASTContext &context, ProgramStateManager &stateMgr)
NonLoc getIndex() const
Definition: MemRegion.h:1096
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:460
static bool isWithinConstantOverflowBounds(SymbolRef Sym, ProgramStateRef State)
const RecordDecl * getParent() const
Returns the parent of this field declaration, which is the struct in which this field is defined...
Definition: Decl.h:2705
const MemRegion * getRegion() const
Definition: MemRegion.h:77
MemSpaceRegion - A memory region that represents a "memory space"; for example, the set of global var...
Definition: MemRegion.h:194
Value representing integer constant.
Definition: SVals.h:374
SymbolRef getAsLocSymbol(bool IncludeBaseRegions=false) const
If this SVal is a location and wraps a symbol, return that SymbolRef.
Definition: SVals.cpp:85
QualType getElementType() const
Definition: MemRegion.h:1100
bool isAdditiveOp() const
Definition: Expr.h:3101
Symbolic value.
Definition: SymExpr.h:30
const MemRegion * getSuperRegion() const
Definition: MemRegion.h:443
Represents a struct/union/class.
Definition: Decl.h:3548
const PTMDataType getPTMData() const
Definition: SVals.h:526
const SymbolicRegion * getSymbolicBase() const
If this is a symbolic region, returns the region.
Definition: MemRegion.cpp:1173
static NonLoc doRearrangeUnchecked(ProgramStateRef State, BinaryOperator::Opcode Op, SymbolRef LSym, llvm::APSInt LInt, SymbolRef RSym, llvm::APSInt RInt)
static Opcode reverseComparisonOp(Opcode Opc)
Definition: Expr.h:3130
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:150
static bool isInRelation(BinaryOperator::Opcode Rel, SymbolRef Sym, llvm::APSInt Bound, ProgramStateRef State)
Value representing pointer-to-member.
Definition: SVals.h:519
LineState State
field_range fields() const
Definition: Decl.h:3764
const FieldDecl * getDecl() const
Definition: MemRegion.h:1010
Represents a member of a struct/union/class.
Definition: Decl.h:2521
bool isReferenceType() const
Definition: Type.h:6040
FullSValVisitor - a convenient mixed visitor for all three: SVal, SymExpr and MemRegion subclasses...
Definition: SValVisitor.h:138
i32 captured_struct **param SharedsTy A type which contains references the shared variables *param Shareds Context with the list of shared variables from the p *TaskFunction *param Data Additional data for task generation like final * state
const SymExpr * getAsSymbolicExpression() const
getAsSymbolicExpression - If this Sval wraps a symbolic expression then return that expression...
Definition: SVals.cpp:137
bool isIntegralOrEnumerationType() const
Determine whether this type is an integral or enumeration type.
Definition: Type.h:6311
static bool isLocType(QualType T)
Definition: SVals.h:327
BinaryOperatorKind
static bool shouldRearrange(ProgramStateRef State, BinaryOperator::Opcode Op, SymbolRef Sym, llvm::APSInt Int, QualType Ty)
const SymIntExpr * getSymIntExpr(const SymExpr *lhs, BinaryOperator::Opcode op, const llvm::APSInt &rhs, QualType t)
bool isUnknown() const
Definition: SVals.h:137
loc::ConcreteInt makeIntLocVal(const llvm::APSInt &integer)
Definition: SValBuilder.h:295
A record of the "type" of an APSInt, used for conversions.
Definition: APSIntType.h:20
Represents a symbolic expression like &#39;x&#39; + 3.
Represent a region&#39;s offset within the top level base region.
Definition: MemRegion.h:62
const MemSpaceRegion * getMemorySpace() const
Definition: MemRegion.cpp:1093
virtual QualType getType() const =0
static std::pair< SymbolRef, llvm::APSInt > decomposeSymbol(SymbolRef Sym, BasicValueFactory &BV)
SymbolRef getAsSymbol(bool IncludeBaseRegions=false) const
If this SVal wraps a symbol return that SymbolRef.
Definition: SVals.cpp:127
static Opcode negateComparisonOp(Opcode Opc)
Definition: Expr.h:3117
unsigned getSubKind() const
Definition: SVals.h:120
Loc makeLoc(SymbolRef sym)
Definition: SValBuilder.h:354
SymbolicRegion - A special, "non-concrete" region.
Definition: MemRegion.h:759
const FunctionProtoType * T
AnalyzerOptions & getAnalyzerOptions() override
QualType getConditionType() const
Definition: SValBuilder.h:161
static SVal getValue(SVal val, SValBuilder &svalBuilder)
SVal evalBinOp(ProgramStateRef state, BinaryOperator::Opcode op, SVal lhs, SVal rhs, QualType type)
bool isUnionType() const
Definition: Type.cpp:436
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:719
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
bool isComparisonOp() const
Definition: Expr.h:3115
llvm::APSInt getMaxValue() const LLVM_READONLY
Returns the maximum value for this type.
Definition: APSIntType.h:66
const SymSymExpr * getSymSymExpr(const SymExpr *lhs, BinaryOperator::Opcode op, const SymExpr *rhs, QualType t)
const SymExpr * getLHS() const
FunctionCodeRegion - A region that represents code texts of function.
Definition: MemRegion.h:576
const MemRegion * getAsRegion() const
Definition: SVals.cpp:151
SVal - This represents a symbolic expression, which can be either an L-value or an R-value...
Definition: SVals.h:76
bool isSignedIntegerOrEnumerationType() const
Determines whether this is an integer type that is signed or an enumeration types whose underlying ty...
Definition: Type.cpp:1823
bool isAnyPointerType() const
Definition: Type.h:6032
QualType getType() const override
virtual SVal evalBinOpNN(ProgramStateRef state, BinaryOperator::Opcode op, NonLoc lhs, NonLoc rhs, QualType resultTy)=0
Create a new value which represents a binary expression with two non- location operands.
llvm::APSInt getValue(uint64_t RawValue) const LLVM_READONLY
Definition: APSIntType.h:70
llvm::APSInt convert(const llvm::APSInt &Value) const LLVM_READONLY
Convert and return a new APSInt with the given value, but this type&#39;s bit width and signedness...
Definition: APSIntType.h:49
Dataflow Directional Tag Classes.
bool isZeroConstant() const
Definition: SVals.cpp:230
bool isShiftOp() const
Definition: Expr.h:3103
const llvm::APSInt & getRHS() const
bool isBooleanType() const
Definition: Type.h:6324
Represents symbolic expression.
Definition: SVals.h:347
unsigned computeComplexity() const
const SymExpr * getRHS() const
unsigned getIntWidth(QualType T) const
APSIntType getAPSIntType(QualType T) const
Returns the type of the APSInt used to store values of the given QualType.
T castAs() const
Convert to the specified SVal type, asserting that this SVal is of the desired type.
Definition: SVals.h:104
BasicValueFactory & getBasicValueFactory()
Definition: SValBuilder.h:169
SubRegion - A region that subsets another larger region.
Definition: MemRegion.h:431
SymbolRef getSymbol() const
Definition: SVals.h:352
RegionOffset getAsOffset() const
Compute the offset within the top level memory object.
Definition: MemRegion.cpp:1449
bool isUnsigned() const
Definition: APSIntType.h:32
int64_t getOffset() const
Definition: MemRegion.h:81
uint64_t getTypeSize(QualType T) const
Return the size of the specified (complete) type T, in bits.
Definition: ASTContext.h:2026
CanQualType getCanonicalType(QualType T) const
Return the canonical (structural) type corresponding to the specified potentially non-canonical type ...
Definition: ASTContext.h:2193
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:13503
BinaryOperator::Opcode getOpcode() const
bool isVoidType() const
Definition: Type.h:6255
void apply(llvm::APSInt &Value) const
Convert a given APSInt, in place, to match this type.
Definition: APSIntType.h:38
static Optional< NonLoc > tryRearrange(ProgramStateRef State, BinaryOperator::Opcode Op, NonLoc Lhs, NonLoc Rhs, QualType ResultTy)
const MemRegion * getBaseRegion() const
Definition: MemRegion.cpp:1125
ElementRegin is used to represent both array elements and casts.
Definition: MemRegion.h:1076
virtual const llvm::APSInt * getKnownValue(ProgramStateRef state, SVal val)=0
Evaluates a given SVal.
__DEVICE__ int max(int __a, int __b)
Represents a symbolic expression like &#39;x&#39; + &#39;y&#39;.
bool hasSymbolicOffset() const
Definition: MemRegion.h:79
bool isUnknownOrUndef() const
Definition: SVals.h:145
A symbol representing data which can be stored in a memory location (region).
Definition: SymExpr.h:115
const SymExpr * getLHS() const
virtual AnalysisManager & getAnalysisManager()=0
static SVal evalBinOpFieldRegionFieldRegion(const FieldRegion *LeftFR, const FieldRegion *RightFR, BinaryOperator::Opcode op, QualType resultTy, SimpleSValBuilder &SVB)