clang  10.0.0svn
BugReporterVisitors.cpp
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1 //===- BugReporterVisitors.cpp - Helpers for reporting bugs ---------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines a set of BugReporter "visitors" which can be used to
10 // enhance the diagnostics reported for a bug.
11 //
12 //===----------------------------------------------------------------------===//
13 
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/Decl.h"
17 #include "clang/AST/DeclBase.h"
18 #include "clang/AST/DeclCXX.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/ExprCXX.h"
21 #include "clang/AST/ExprObjC.h"
22 #include "clang/AST/Stmt.h"
23 #include "clang/AST/Type.h"
27 #include "clang/Analysis/CFG.h"
32 #include "clang/Basic/LLVM.h"
35 #include "clang/Lex/Lexer.h"
49 #include "llvm/ADT/ArrayRef.h"
50 #include "llvm/ADT/None.h"
51 #include "llvm/ADT/Optional.h"
52 #include "llvm/ADT/STLExtras.h"
53 #include "llvm/ADT/SmallPtrSet.h"
54 #include "llvm/ADT/SmallString.h"
55 #include "llvm/ADT/SmallVector.h"
56 #include "llvm/ADT/StringExtras.h"
57 #include "llvm/ADT/StringRef.h"
58 #include "llvm/Support/Casting.h"
59 #include "llvm/Support/ErrorHandling.h"
60 #include "llvm/Support/raw_ostream.h"
61 #include <cassert>
62 #include <deque>
63 #include <memory>
64 #include <string>
65 #include <utility>
66 
67 using namespace clang;
68 using namespace ento;
69 
70 //===----------------------------------------------------------------------===//
71 // Utility functions.
72 //===----------------------------------------------------------------------===//
73 
74 static const Expr *peelOffPointerArithmetic(const BinaryOperator *B) {
75  if (B->isAdditiveOp() && B->getType()->isPointerType()) {
76  if (B->getLHS()->getType()->isPointerType()) {
77  return B->getLHS();
78  } else if (B->getRHS()->getType()->isPointerType()) {
79  return B->getRHS();
80  }
81  }
82  return nullptr;
83 }
84 
85 /// Given that expression S represents a pointer that would be dereferenced,
86 /// try to find a sub-expression from which the pointer came from.
87 /// This is used for tracking down origins of a null or undefined value:
88 /// "this is null because that is null because that is null" etc.
89 /// We wipe away field and element offsets because they merely add offsets.
90 /// We also wipe away all casts except lvalue-to-rvalue casts, because the
91 /// latter represent an actual pointer dereference; however, we remove
92 /// the final lvalue-to-rvalue cast before returning from this function
93 /// because it demonstrates more clearly from where the pointer rvalue was
94 /// loaded. Examples:
95 /// x->y.z ==> x (lvalue)
96 /// foo()->y.z ==> foo() (rvalue)
97 const Expr *bugreporter::getDerefExpr(const Stmt *S) {
98  const auto *E = dyn_cast<Expr>(S);
99  if (!E)
100  return nullptr;
101 
102  while (true) {
103  if (const auto *CE = dyn_cast<CastExpr>(E)) {
104  if (CE->getCastKind() == CK_LValueToRValue) {
105  // This cast represents the load we're looking for.
106  break;
107  }
108  E = CE->getSubExpr();
109  } else if (const auto *B = dyn_cast<BinaryOperator>(E)) {
110  // Pointer arithmetic: '*(x + 2)' -> 'x') etc.
111  if (const Expr *Inner = peelOffPointerArithmetic(B)) {
112  E = Inner;
113  } else {
114  // Probably more arithmetic can be pattern-matched here,
115  // but for now give up.
116  break;
117  }
118  } else if (const auto *U = dyn_cast<UnaryOperator>(E)) {
119  if (U->getOpcode() == UO_Deref || U->getOpcode() == UO_AddrOf ||
120  (U->isIncrementDecrementOp() && U->getType()->isPointerType())) {
121  // Operators '*' and '&' don't actually mean anything.
122  // We look at casts instead.
123  E = U->getSubExpr();
124  } else {
125  // Probably more arithmetic can be pattern-matched here,
126  // but for now give up.
127  break;
128  }
129  }
130  // Pattern match for a few useful cases: a[0], p->f, *p etc.
131  else if (const auto *ME = dyn_cast<MemberExpr>(E)) {
132  E = ME->getBase();
133  } else if (const auto *IvarRef = dyn_cast<ObjCIvarRefExpr>(E)) {
134  E = IvarRef->getBase();
135  } else if (const auto *AE = dyn_cast<ArraySubscriptExpr>(E)) {
136  E = AE->getBase();
137  } else if (const auto *PE = dyn_cast<ParenExpr>(E)) {
138  E = PE->getSubExpr();
139  } else if (const auto *FE = dyn_cast<FullExpr>(E)) {
140  E = FE->getSubExpr();
141  } else {
142  // Other arbitrary stuff.
143  break;
144  }
145  }
146 
147  // Special case: remove the final lvalue-to-rvalue cast, but do not recurse
148  // deeper into the sub-expression. This way we return the lvalue from which
149  // our pointer rvalue was loaded.
150  if (const auto *CE = dyn_cast<ImplicitCastExpr>(E))
151  if (CE->getCastKind() == CK_LValueToRValue)
152  E = CE->getSubExpr();
153 
154  return E;
155 }
156 
157 /// Comparing internal representations of symbolic values (via
158 /// SVal::operator==()) is a valid way to check if the value was updated,
159 /// unless it's a LazyCompoundVal that may have a different internal
160 /// representation every time it is loaded from the state. In this function we
161 /// do an approximate comparison for lazy compound values, checking that they
162 /// are the immediate snapshots of the tracked region's bindings within the
163 /// node's respective states but not really checking that these snapshots
164 /// actually contain the same set of bindings.
165 static bool hasVisibleUpdate(const ExplodedNode *LeftNode, SVal LeftVal,
166  const ExplodedNode *RightNode, SVal RightVal) {
167  if (LeftVal == RightVal)
168  return true;
169 
170  const auto LLCV = LeftVal.getAs<nonloc::LazyCompoundVal>();
171  if (!LLCV)
172  return false;
173 
174  const auto RLCV = RightVal.getAs<nonloc::LazyCompoundVal>();
175  if (!RLCV)
176  return false;
177 
178  return LLCV->getRegion() == RLCV->getRegion() &&
179  LLCV->getStore() == LeftNode->getState()->getStore() &&
180  RLCV->getStore() == RightNode->getState()->getStore();
181 }
182 
183 static Optional<SVal> getSValForVar(const Expr *CondVarExpr,
184  const ExplodedNode *N) {
185  ProgramStateRef State = N->getState();
186  const LocationContext *LCtx = N->getLocationContext();
187 
188  assert(CondVarExpr);
189  CondVarExpr = CondVarExpr->IgnoreImpCasts();
190 
191  // The declaration of the value may rely on a pointer so take its l-value.
192  // FIXME: As seen in VisitCommonDeclRefExpr, sometimes DeclRefExpr may
193  // evaluate to a FieldRegion when it refers to a declaration of a lambda
194  // capture variable. We most likely need to duplicate that logic here.
195  if (const auto *DRE = dyn_cast<DeclRefExpr>(CondVarExpr))
196  if (const auto *VD = dyn_cast<VarDecl>(DRE->getDecl()))
197  return State->getSVal(State->getLValue(VD, LCtx));
198 
199  if (const auto *ME = dyn_cast<MemberExpr>(CondVarExpr))
200  if (const auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()))
201  if (auto FieldL = State->getSVal(ME, LCtx).getAs<Loc>())
202  return State->getRawSVal(*FieldL, FD->getType());
203 
204  return None;
205 }
206 
208 getConcreteIntegerValue(const Expr *CondVarExpr, const ExplodedNode *N) {
209 
210  if (Optional<SVal> V = getSValForVar(CondVarExpr, N))
211  if (auto CI = V->getAs<nonloc::ConcreteInt>())
212  return &CI->getValue();
213  return None;
214 }
215 
216 static bool isVarAnInterestingCondition(const Expr *CondVarExpr,
217  const ExplodedNode *N,
218  const PathSensitiveBugReport *B) {
219  // Even if this condition is marked as interesting, it isn't *that*
220  // interesting if it didn't happen in a nested stackframe, the user could just
221  // follow the arrows.
222  if (!B->getErrorNode()->getStackFrame()->isParentOf(N->getStackFrame()))
223  return false;
224 
225  if (Optional<SVal> V = getSValForVar(CondVarExpr, N))
226  if (Optional<bugreporter::TrackingKind> K = B->getInterestingnessKind(*V))
227  return *K == bugreporter::TrackingKind::Condition;
228 
229  return false;
230 }
231 
232 static bool isInterestingExpr(const Expr *E, const ExplodedNode *N,
233  const PathSensitiveBugReport *B) {
234  if (Optional<SVal> V = getSValForVar(E, N))
235  return B->getInterestingnessKind(*V).hasValue();
236  return false;
237 }
238 
239 /// \return name of the macro inside the location \p Loc.
240 static StringRef getMacroName(SourceLocation Loc,
241  BugReporterContext &BRC) {
243  Loc,
244  BRC.getSourceManager(),
245  BRC.getASTContext().getLangOpts());
246 }
247 
248 /// \return Whether given spelling location corresponds to an expansion
249 /// of a function-like macro.
251  const SourceManager &SM) {
252  if (!Loc.isMacroID())
253  return false;
254  while (SM.isMacroArgExpansion(Loc))
255  Loc = SM.getImmediateExpansionRange(Loc).getBegin();
256  std::pair<FileID, unsigned> TLInfo = SM.getDecomposedLoc(Loc);
257  SrcMgr::SLocEntry SE = SM.getSLocEntry(TLInfo.first);
258  const SrcMgr::ExpansionInfo &EInfo = SE.getExpansion();
259  return EInfo.isFunctionMacroExpansion();
260 }
261 
262 /// \return Whether \c RegionOfInterest was modified at \p N,
263 /// where \p ValueAfter is \c RegionOfInterest's value at the end of the
264 /// stack frame.
265 static bool wasRegionOfInterestModifiedAt(const SubRegion *RegionOfInterest,
266  const ExplodedNode *N,
267  SVal ValueAfter) {
268  ProgramStateRef State = N->getState();
269  ProgramStateManager &Mgr = N->getState()->getStateManager();
270 
271  if (!N->getLocationAs<PostStore>() && !N->getLocationAs<PostInitializer>() &&
272  !N->getLocationAs<PostStmt>())
273  return false;
274 
275  // Writing into region of interest.
276  if (auto PS = N->getLocationAs<PostStmt>())
277  if (auto *BO = PS->getStmtAs<BinaryOperator>())
278  if (BO->isAssignmentOp() && RegionOfInterest->isSubRegionOf(
279  N->getSVal(BO->getLHS()).getAsRegion()))
280  return true;
281 
282  // SVal after the state is possibly different.
283  SVal ValueAtN = N->getState()->getSVal(RegionOfInterest);
284  if (!Mgr.getSValBuilder()
285  .areEqual(State, ValueAtN, ValueAfter)
286  .isConstrainedTrue() &&
287  (!ValueAtN.isUndef() || !ValueAfter.isUndef()))
288  return true;
289 
290  return false;
291 }
292 
293 //===----------------------------------------------------------------------===//
294 // Implementation of BugReporterVisitor.
295 //===----------------------------------------------------------------------===//
296 
297 PathDiagnosticPieceRef BugReporterVisitor::getEndPath(BugReporterContext &,
298  const ExplodedNode *,
299  PathSensitiveBugReport &) {
300  return nullptr;
301 }
302 
303 void BugReporterVisitor::finalizeVisitor(BugReporterContext &,
304  const ExplodedNode *,
305  PathSensitiveBugReport &) {}
306 
308 BugReporterVisitor::getDefaultEndPath(const BugReporterContext &BRC,
309  const ExplodedNode *EndPathNode,
310  const PathSensitiveBugReport &BR) {
311  PathDiagnosticLocation L = BR.getLocation();
312  const auto &Ranges = BR.getRanges();
313 
314  // Only add the statement itself as a range if we didn't specify any
315  // special ranges for this report.
316  auto P = std::make_shared<PathDiagnosticEventPiece>(
317  L, BR.getDescription(), Ranges.begin() == Ranges.end());
318  for (SourceRange Range : Ranges)
319  P->addRange(Range);
320 
321  return P;
322 }
323 
324 //===----------------------------------------------------------------------===//
325 // Implementation of NoStoreFuncVisitor.
326 //===----------------------------------------------------------------------===//
327 
328 namespace {
329 
330 /// Put a diagnostic on return statement of all inlined functions
331 /// for which the region of interest \p RegionOfInterest was passed into,
332 /// but not written inside, and it has caused an undefined read or a null
333 /// pointer dereference outside.
334 class NoStoreFuncVisitor final : public BugReporterVisitor {
335  const SubRegion *RegionOfInterest;
336  MemRegionManager &MmrMgr;
337  const SourceManager &SM;
338  const PrintingPolicy &PP;
339  bugreporter::TrackingKind TKind;
340 
341  /// Recursion limit for dereferencing fields when looking for the
342  /// region of interest.
343  /// The limit of two indicates that we will dereference fields only once.
344  static const unsigned DEREFERENCE_LIMIT = 2;
345 
346  /// Frames writing into \c RegionOfInterest.
347  /// This visitor generates a note only if a function does not write into
348  /// a region of interest. This information is not immediately available
349  /// by looking at the node associated with the exit from the function
350  /// (usually the return statement). To avoid recomputing the same information
351  /// many times (going up the path for each node and checking whether the
352  /// region was written into) we instead lazily compute the
353  /// stack frames along the path which write into the region of interest.
354  llvm::SmallPtrSet<const StackFrameContext *, 32> FramesModifyingRegion;
355  llvm::SmallPtrSet<const StackFrameContext *, 32> FramesModifyingCalculated;
356 
357  using RegionVector = SmallVector<const MemRegion *, 5>;
358 
359 public:
360  NoStoreFuncVisitor(const SubRegion *R, bugreporter::TrackingKind TKind)
361  : RegionOfInterest(R), MmrMgr(*R->getMemRegionManager()),
362  SM(MmrMgr.getContext().getSourceManager()),
363  PP(MmrMgr.getContext().getPrintingPolicy()), TKind(TKind) {}
364 
365  void Profile(llvm::FoldingSetNodeID &ID) const override {
366  static int Tag = 0;
367  ID.AddPointer(&Tag);
368  ID.AddPointer(RegionOfInterest);
369  }
370 
371  void *getTag() const {
372  static int Tag = 0;
373  return static_cast<void *>(&Tag);
374  }
375 
376  PathDiagnosticPieceRef VisitNode(const ExplodedNode *N,
377  BugReporterContext &BR,
378  PathSensitiveBugReport &R) override;
379 
380 private:
381  /// Attempts to find the region of interest in a given record decl,
382  /// by either following the base classes or fields.
383  /// Dereferences fields up to a given recursion limit.
384  /// Note that \p Vec is passed by value, leading to quadratic copying cost,
385  /// but it's OK in practice since its length is limited to DEREFERENCE_LIMIT.
386  /// \return A chain fields leading to the region of interest or None.
388  findRegionOfInterestInRecord(const RecordDecl *RD, ProgramStateRef State,
389  const MemRegion *R, const RegionVector &Vec = {},
390  int depth = 0);
391 
392  /// Check and lazily calculate whether the region of interest is
393  /// modified in the stack frame to which \p N belongs.
394  /// The calculation is cached in FramesModifyingRegion.
395  bool isRegionOfInterestModifiedInFrame(const ExplodedNode *N) {
396  const LocationContext *Ctx = N->getLocationContext();
397  const StackFrameContext *SCtx = Ctx->getStackFrame();
398  if (!FramesModifyingCalculated.count(SCtx))
399  findModifyingFrames(N);
400  return FramesModifyingRegion.count(SCtx);
401  }
402 
403  /// Write to \c FramesModifyingRegion all stack frames along
404  /// the path in the current stack frame which modify \c RegionOfInterest.
405  void findModifyingFrames(const ExplodedNode *N);
406 
407  /// Consume the information on the no-store stack frame in order to
408  /// either emit a note or suppress the report enirely.
409  /// \return Diagnostics piece for region not modified in the current function,
410  /// if it decides to emit one.
412  maybeEmitNote(PathSensitiveBugReport &R, const CallEvent &Call,
413  const ExplodedNode *N, const RegionVector &FieldChain,
414  const MemRegion *MatchedRegion, StringRef FirstElement,
415  bool FirstIsReferenceType, unsigned IndirectionLevel);
416 
417  /// Pretty-print region \p MatchedRegion to \p os.
418  /// \return Whether printing succeeded.
419  bool prettyPrintRegionName(StringRef FirstElement, bool FirstIsReferenceType,
420  const MemRegion *MatchedRegion,
421  const RegionVector &FieldChain,
422  int IndirectionLevel,
423  llvm::raw_svector_ostream &os);
424 
425  /// Print first item in the chain, return new separator.
426  static StringRef prettyPrintFirstElement(StringRef FirstElement,
427  bool MoreItemsExpected,
428  int IndirectionLevel,
429  llvm::raw_svector_ostream &os);
430 };
431 
432 } // end of anonymous namespace
433 
434 /// \return Whether the method declaration \p Parent
435 /// syntactically has a binary operation writing into the ivar \p Ivar.
437  const ObjCIvarDecl *Ivar) {
438  using namespace ast_matchers;
439  const char *IvarBind = "Ivar";
440  if (!Parent || !Parent->hasBody())
441  return false;
442  StatementMatcher WriteIntoIvarM = binaryOperator(
443  hasOperatorName("="),
444  hasLHS(ignoringParenImpCasts(
445  objcIvarRefExpr(hasDeclaration(equalsNode(Ivar))).bind(IvarBind))));
446  StatementMatcher ParentM = stmt(hasDescendant(WriteIntoIvarM));
447  auto Matches = match(ParentM, *Parent->getBody(), Parent->getASTContext());
448  for (BoundNodes &Match : Matches) {
449  auto IvarRef = Match.getNodeAs<ObjCIvarRefExpr>(IvarBind);
450  if (IvarRef->isFreeIvar())
451  return true;
452 
453  const Expr *Base = IvarRef->getBase();
454  if (const auto *ICE = dyn_cast<ImplicitCastExpr>(Base))
455  Base = ICE->getSubExpr();
456 
457  if (const auto *DRE = dyn_cast<DeclRefExpr>(Base))
458  if (const auto *ID = dyn_cast<ImplicitParamDecl>(DRE->getDecl()))
459  if (ID->getParameterKind() == ImplicitParamDecl::ObjCSelf)
460  return true;
461 
462  return false;
463  }
464  return false;
465 }
466 
467 /// Get parameters associated with runtime definition in order
468 /// to get the correct parameter name.
469 static ArrayRef<ParmVarDecl *> getCallParameters(CallEventRef<> Call) {
470  // Use runtime definition, if available.
471  RuntimeDefinition RD = Call->getRuntimeDefinition();
472  if (const auto *FD = dyn_cast_or_null<FunctionDecl>(RD.getDecl()))
473  return FD->parameters();
474  if (const auto *MD = dyn_cast_or_null<ObjCMethodDecl>(RD.getDecl()))
475  return MD->parameters();
476 
477  return Call->parameters();
478 }
479 
480 /// \return whether \p Ty points to a const type, or is a const reference.
481 static bool isPointerToConst(QualType Ty) {
482  return !Ty->getPointeeType().isNull() &&
484 }
485 
486 /// Attempts to find the region of interest in a given CXX decl,
487 /// by either following the base classes or fields.
488 /// Dereferences fields up to a given recursion limit.
489 /// Note that \p Vec is passed by value, leading to quadratic copying cost,
490 /// but it's OK in practice since its length is limited to DEREFERENCE_LIMIT.
491 /// \return A chain fields leading to the region of interest or None.
493 NoStoreFuncVisitor::findRegionOfInterestInRecord(
494  const RecordDecl *RD, ProgramStateRef State, const MemRegion *R,
495  const NoStoreFuncVisitor::RegionVector &Vec /* = {} */,
496  int depth /* = 0 */) {
497 
498  if (depth == DEREFERENCE_LIMIT) // Limit the recursion depth.
499  return None;
500 
501  if (const auto *RDX = dyn_cast<CXXRecordDecl>(RD))
502  if (!RDX->hasDefinition())
503  return None;
504 
505  // Recursively examine the base classes.
506  // Note that following base classes does not increase the recursion depth.
507  if (const auto *RDX = dyn_cast<CXXRecordDecl>(RD))
508  for (const auto II : RDX->bases())
509  if (const RecordDecl *RRD = II.getType()->getAsRecordDecl())
510  if (Optional<RegionVector> Out =
511  findRegionOfInterestInRecord(RRD, State, R, Vec, depth))
512  return Out;
513 
514  for (const FieldDecl *I : RD->fields()) {
515  QualType FT = I->getType();
516  const FieldRegion *FR = MmrMgr.getFieldRegion(I, cast<SubRegion>(R));
517  const SVal V = State->getSVal(FR);
518  const MemRegion *VR = V.getAsRegion();
519 
520  RegionVector VecF = Vec;
521  VecF.push_back(FR);
522 
523  if (RegionOfInterest == VR)
524  return VecF;
525 
526  if (const RecordDecl *RRD = FT->getAsRecordDecl())
527  if (auto Out =
528  findRegionOfInterestInRecord(RRD, State, FR, VecF, depth + 1))
529  return Out;
530 
531  QualType PT = FT->getPointeeType();
532  if (PT.isNull() || PT->isVoidType() || !VR)
533  continue;
534 
535  if (const RecordDecl *RRD = PT->getAsRecordDecl())
536  if (Optional<RegionVector> Out =
537  findRegionOfInterestInRecord(RRD, State, VR, VecF, depth + 1))
538  return Out;
539  }
540 
541  return None;
542 }
543 
545 NoStoreFuncVisitor::VisitNode(const ExplodedNode *N, BugReporterContext &BR,
546  PathSensitiveBugReport &R) {
547 
548  const LocationContext *Ctx = N->getLocationContext();
549  const StackFrameContext *SCtx = Ctx->getStackFrame();
550  ProgramStateRef State = N->getState();
551  auto CallExitLoc = N->getLocationAs<CallExitBegin>();
552 
553  // No diagnostic if region was modified inside the frame.
554  if (!CallExitLoc || isRegionOfInterestModifiedInFrame(N))
555  return nullptr;
556 
557  CallEventRef<> Call =
558  BR.getStateManager().getCallEventManager().getCaller(SCtx, State);
559 
560  // Region of interest corresponds to an IVar, exiting a method
561  // which could have written into that IVar, but did not.
562  if (const auto *MC = dyn_cast<ObjCMethodCall>(Call)) {
563  if (const auto *IvarR = dyn_cast<ObjCIvarRegion>(RegionOfInterest)) {
564  const MemRegion *SelfRegion = MC->getReceiverSVal().getAsRegion();
565  if (RegionOfInterest->isSubRegionOf(SelfRegion) &&
566  potentiallyWritesIntoIvar(Call->getRuntimeDefinition().getDecl(),
567  IvarR->getDecl()))
568  return maybeEmitNote(R, *Call, N, {}, SelfRegion, "self",
569  /*FirstIsReferenceType=*/false, 1);
570  }
571  }
572 
573  if (const auto *CCall = dyn_cast<CXXConstructorCall>(Call)) {
574  const MemRegion *ThisR = CCall->getCXXThisVal().getAsRegion();
575  if (RegionOfInterest->isSubRegionOf(ThisR) &&
576  !CCall->getDecl()->isImplicit())
577  return maybeEmitNote(R, *Call, N, {}, ThisR, "this",
578  /*FirstIsReferenceType=*/false, 1);
579 
580  // Do not generate diagnostics for not modified parameters in
581  // constructors.
582  return nullptr;
583  }
584 
585  ArrayRef<ParmVarDecl *> parameters = getCallParameters(Call);
586  for (unsigned I = 0; I < Call->getNumArgs() && I < parameters.size(); ++I) {
587  const ParmVarDecl *PVD = parameters[I];
588  SVal V = Call->getArgSVal(I);
589  bool ParamIsReferenceType = PVD->getType()->isReferenceType();
590  std::string ParamName = PVD->getNameAsString();
591 
592  int IndirectionLevel = 1;
593  QualType T = PVD->getType();
594  while (const MemRegion *MR = V.getAsRegion()) {
595  if (RegionOfInterest->isSubRegionOf(MR) && !isPointerToConst(T))
596  return maybeEmitNote(R, *Call, N, {}, MR, ParamName,
597  ParamIsReferenceType, IndirectionLevel);
598 
599  QualType PT = T->getPointeeType();
600  if (PT.isNull() || PT->isVoidType())
601  break;
602 
603  if (const RecordDecl *RD = PT->getAsRecordDecl())
605  findRegionOfInterestInRecord(RD, State, MR))
606  return maybeEmitNote(R, *Call, N, *P, RegionOfInterest, ParamName,
607  ParamIsReferenceType, IndirectionLevel);
608 
609  V = State->getSVal(MR, PT);
610  T = PT;
611  IndirectionLevel++;
612  }
613  }
614 
615  return nullptr;
616 }
617 
618 void NoStoreFuncVisitor::findModifyingFrames(const ExplodedNode *N) {
619  assert(N->getLocationAs<CallExitBegin>());
620  ProgramStateRef LastReturnState = N->getState();
621  SVal ValueAtReturn = LastReturnState->getSVal(RegionOfInterest);
622  const LocationContext *Ctx = N->getLocationContext();
623  const StackFrameContext *OriginalSCtx = Ctx->getStackFrame();
624 
625  do {
626  ProgramStateRef State = N->getState();
627  auto CallExitLoc = N->getLocationAs<CallExitBegin>();
628  if (CallExitLoc) {
629  LastReturnState = State;
630  ValueAtReturn = LastReturnState->getSVal(RegionOfInterest);
631  }
632 
633  FramesModifyingCalculated.insert(N->getLocationContext()->getStackFrame());
634 
635  if (wasRegionOfInterestModifiedAt(RegionOfInterest, N, ValueAtReturn)) {
636  const StackFrameContext *SCtx = N->getStackFrame();
637  while (!SCtx->inTopFrame()) {
638  auto p = FramesModifyingRegion.insert(SCtx);
639  if (!p.second)
640  break; // Frame and all its parents already inserted.
641  SCtx = SCtx->getParent()->getStackFrame();
642  }
643  }
644 
645  // Stop calculation at the call to the current function.
646  if (auto CE = N->getLocationAs<CallEnter>())
647  if (CE->getCalleeContext() == OriginalSCtx)
648  break;
649 
650  N = N->getFirstPred();
651  } while (N);
652 }
653 
654 static llvm::StringLiteral WillBeUsedForACondition =
655  ", which participates in a condition later";
656 
657 PathDiagnosticPieceRef NoStoreFuncVisitor::maybeEmitNote(
658  PathSensitiveBugReport &R, const CallEvent &Call, const ExplodedNode *N,
659  const RegionVector &FieldChain, const MemRegion *MatchedRegion,
660  StringRef FirstElement, bool FirstIsReferenceType,
661  unsigned IndirectionLevel) {
662  // Optimistically suppress uninitialized value bugs that result
663  // from system headers having a chance to initialize the value
664  // but failing to do so. It's too unlikely a system header's fault.
665  // It's much more likely a situation in which the function has a failure
666  // mode that the user decided not to check. If we want to hunt such
667  // omitted checks, we should provide an explicit function-specific note
668  // describing the precondition under which the function isn't supposed to
669  // initialize its out-parameter, and additionally check that such
670  // precondition can actually be fulfilled on the current path.
671  if (Call.isInSystemHeader()) {
672  // We make an exception for system header functions that have no branches.
673  // Such functions unconditionally fail to initialize the variable.
674  // If they call other functions that have more paths within them,
675  // this suppression would still apply when we visit these inner functions.
676  // One common example of a standard function that doesn't ever initialize
677  // its out parameter is operator placement new; it's up to the follow-up
678  // constructor (if any) to initialize the memory.
679  if (!N->getStackFrame()->getCFG()->isLinear())
680  R.markInvalid(getTag(), nullptr);
681  return nullptr;
682  }
683 
684  PathDiagnosticLocation L =
685  PathDiagnosticLocation::create(N->getLocation(), SM);
686 
687  // For now this shouldn't trigger, but once it does (as we add more
688  // functions to the body farm), we'll need to decide if these reports
689  // are worth suppressing as well.
690  if (!L.hasValidLocation())
691  return nullptr;
692 
693  SmallString<256> sbuf;
694  llvm::raw_svector_ostream os(sbuf);
695  os << "Returning without writing to '";
696 
697  // Do not generate the note if failed to pretty-print.
698  if (!prettyPrintRegionName(FirstElement, FirstIsReferenceType, MatchedRegion,
699  FieldChain, IndirectionLevel, os))
700  return nullptr;
701 
702  os << "'";
703  if (TKind == bugreporter::TrackingKind::Condition)
705  return std::make_shared<PathDiagnosticEventPiece>(L, os.str());
706 }
707 
708 bool NoStoreFuncVisitor::prettyPrintRegionName(StringRef FirstElement,
709  bool FirstIsReferenceType,
710  const MemRegion *MatchedRegion,
711  const RegionVector &FieldChain,
712  int IndirectionLevel,
713  llvm::raw_svector_ostream &os) {
714 
715  if (FirstIsReferenceType)
716  IndirectionLevel--;
717 
718  RegionVector RegionSequence;
719 
720  // Add the regions in the reverse order, then reverse the resulting array.
721  assert(RegionOfInterest->isSubRegionOf(MatchedRegion));
722  const MemRegion *R = RegionOfInterest;
723  while (R != MatchedRegion) {
724  RegionSequence.push_back(R);
725  R = cast<SubRegion>(R)->getSuperRegion();
726  }
727  std::reverse(RegionSequence.begin(), RegionSequence.end());
728  RegionSequence.append(FieldChain.begin(), FieldChain.end());
729 
730  StringRef Sep;
731  for (const MemRegion *R : RegionSequence) {
732 
733  // Just keep going up to the base region.
734  // Element regions may appear due to casts.
735  if (isa<CXXBaseObjectRegion>(R) || isa<CXXTempObjectRegion>(R))
736  continue;
737 
738  if (Sep.empty())
739  Sep = prettyPrintFirstElement(FirstElement,
740  /*MoreItemsExpected=*/true,
741  IndirectionLevel, os);
742 
743  os << Sep;
744 
745  // Can only reasonably pretty-print DeclRegions.
746  if (!isa<DeclRegion>(R))
747  return false;
748 
749  const auto *DR = cast<DeclRegion>(R);
750  Sep = DR->getValueType()->isAnyPointerType() ? "->" : ".";
751  DR->getDecl()->getDeclName().print(os, PP);
752  }
753 
754  if (Sep.empty())
755  prettyPrintFirstElement(FirstElement,
756  /*MoreItemsExpected=*/false, IndirectionLevel, os);
757  return true;
758 }
759 
760 StringRef NoStoreFuncVisitor::prettyPrintFirstElement(
761  StringRef FirstElement, bool MoreItemsExpected, int IndirectionLevel,
762  llvm::raw_svector_ostream &os) {
763  StringRef Out = ".";
764 
765  if (IndirectionLevel > 0 && MoreItemsExpected) {
766  IndirectionLevel--;
767  Out = "->";
768  }
769 
770  if (IndirectionLevel > 0 && MoreItemsExpected)
771  os << "(";
772 
773  for (int i = 0; i < IndirectionLevel; i++)
774  os << "*";
775  os << FirstElement;
776 
777  if (IndirectionLevel > 0 && MoreItemsExpected)
778  os << ")";
779 
780  return Out;
781 }
782 
783 //===----------------------------------------------------------------------===//
784 // Implementation of MacroNullReturnSuppressionVisitor.
785 //===----------------------------------------------------------------------===//
786 
787 namespace {
788 
789 /// Suppress null-pointer-dereference bugs where dereferenced null was returned
790 /// the macro.
791 class MacroNullReturnSuppressionVisitor final : public BugReporterVisitor {
792  const SubRegion *RegionOfInterest;
793  const SVal ValueAtDereference;
794 
795  // Do not invalidate the reports where the value was modified
796  // after it got assigned to from the macro.
797  bool WasModified = false;
798 
799 public:
800  MacroNullReturnSuppressionVisitor(const SubRegion *R, const SVal V)
801  : RegionOfInterest(R), ValueAtDereference(V) {}
802 
803  PathDiagnosticPieceRef VisitNode(const ExplodedNode *N,
804  BugReporterContext &BRC,
805  PathSensitiveBugReport &BR) override {
806  if (WasModified)
807  return nullptr;
808 
809  auto BugPoint = BR.getErrorNode()->getLocation().getAs<StmtPoint>();
810  if (!BugPoint)
811  return nullptr;
812 
813  const SourceManager &SMgr = BRC.getSourceManager();
814  if (auto Loc = matchAssignment(N)) {
815  if (isFunctionMacroExpansion(*Loc, SMgr)) {
816  std::string MacroName = getMacroName(*Loc, BRC);
817  SourceLocation BugLoc = BugPoint->getStmt()->getBeginLoc();
818  if (!BugLoc.isMacroID() || getMacroName(BugLoc, BRC) != MacroName)
819  BR.markInvalid(getTag(), MacroName.c_str());
820  }
821  }
822 
823  if (wasRegionOfInterestModifiedAt(RegionOfInterest, N, ValueAtDereference))
824  WasModified = true;
825 
826  return nullptr;
827  }
828 
829  static void addMacroVisitorIfNecessary(
830  const ExplodedNode *N, const MemRegion *R,
831  bool EnableNullFPSuppression, PathSensitiveBugReport &BR,
832  const SVal V) {
833  AnalyzerOptions &Options = N->getState()->getAnalysisManager().options;
834  if (EnableNullFPSuppression &&
835  Options.ShouldSuppressNullReturnPaths && V.getAs<Loc>())
836  BR.addVisitor(std::make_unique<MacroNullReturnSuppressionVisitor>(
837  R->getAs<SubRegion>(), V));
838  }
839 
840  void* getTag() const {
841  static int Tag = 0;
842  return static_cast<void *>(&Tag);
843  }
844 
845  void Profile(llvm::FoldingSetNodeID &ID) const override {
846  ID.AddPointer(getTag());
847  }
848 
849 private:
850  /// \return Source location of right hand side of an assignment
851  /// into \c RegionOfInterest, empty optional if none found.
852  Optional<SourceLocation> matchAssignment(const ExplodedNode *N) {
853  const Stmt *S = N->getStmtForDiagnostics();
854  ProgramStateRef State = N->getState();
855  auto *LCtx = N->getLocationContext();
856  if (!S)
857  return None;
858 
859  if (const auto *DS = dyn_cast<DeclStmt>(S)) {
860  if (const auto *VD = dyn_cast<VarDecl>(DS->getSingleDecl()))
861  if (const Expr *RHS = VD->getInit())
862  if (RegionOfInterest->isSubRegionOf(
863  State->getLValue(VD, LCtx).getAsRegion()))
864  return RHS->getBeginLoc();
865  } else if (const auto *BO = dyn_cast<BinaryOperator>(S)) {
866  const MemRegion *R = N->getSVal(BO->getLHS()).getAsRegion();
867  const Expr *RHS = BO->getRHS();
868  if (BO->isAssignmentOp() && RegionOfInterest->isSubRegionOf(R)) {
869  return RHS->getBeginLoc();
870  }
871  }
872  return None;
873  }
874 };
875 
876 } // end of anonymous namespace
877 
878 namespace {
879 
880 /// Emits an extra note at the return statement of an interesting stack frame.
881 ///
882 /// The returned value is marked as an interesting value, and if it's null,
883 /// adds a visitor to track where it became null.
884 ///
885 /// This visitor is intended to be used when another visitor discovers that an
886 /// interesting value comes from an inlined function call.
887 class ReturnVisitor : public BugReporterVisitor {
888  const StackFrameContext *CalleeSFC;
889  enum {
890  Initial,
891  MaybeUnsuppress,
892  Satisfied
893  } Mode = Initial;
894 
895  bool EnableNullFPSuppression;
896  bool ShouldInvalidate = true;
897  AnalyzerOptions& Options;
898  bugreporter::TrackingKind TKind;
899 
900 public:
901  ReturnVisitor(const StackFrameContext *Frame, bool Suppressed,
902  AnalyzerOptions &Options, bugreporter::TrackingKind TKind)
903  : CalleeSFC(Frame), EnableNullFPSuppression(Suppressed),
904  Options(Options), TKind(TKind) {}
905 
906  static void *getTag() {
907  static int Tag = 0;
908  return static_cast<void *>(&Tag);
909  }
910 
911  void Profile(llvm::FoldingSetNodeID &ID) const override {
912  ID.AddPointer(ReturnVisitor::getTag());
913  ID.AddPointer(CalleeSFC);
914  ID.AddBoolean(EnableNullFPSuppression);
915  }
916 
917  /// Adds a ReturnVisitor if the given statement represents a call that was
918  /// inlined.
919  ///
920  /// This will search back through the ExplodedGraph, starting from the given
921  /// node, looking for when the given statement was processed. If it turns out
922  /// the statement is a call that was inlined, we add the visitor to the
923  /// bug report, so it can print a note later.
924  static void addVisitorIfNecessary(const ExplodedNode *Node, const Stmt *S,
925  PathSensitiveBugReport &BR,
926  bool InEnableNullFPSuppression,
927  bugreporter::TrackingKind TKind) {
928  if (!CallEvent::isCallStmt(S))
929  return;
930 
931  // First, find when we processed the statement.
932  // If we work with a 'CXXNewExpr' that is going to be purged away before
933  // its call take place. We would catch that purge in the last condition
934  // as a 'StmtPoint' so we have to bypass it.
935  const bool BypassCXXNewExprEval = isa<CXXNewExpr>(S);
936 
937  // This is moving forward when we enter into another context.
938  const StackFrameContext *CurrentSFC = Node->getStackFrame();
939 
940  do {
941  // If that is satisfied we found our statement as an inlined call.
942  if (Optional<CallExitEnd> CEE = Node->getLocationAs<CallExitEnd>())
943  if (CEE->getCalleeContext()->getCallSite() == S)
944  break;
945 
946  // Try to move forward to the end of the call-chain.
947  Node = Node->getFirstPred();
948  if (!Node)
949  break;
950 
951  const StackFrameContext *PredSFC = Node->getStackFrame();
952 
953  // If that is satisfied we found our statement.
954  // FIXME: This code currently bypasses the call site for the
955  // conservatively evaluated allocator.
956  if (!BypassCXXNewExprEval)
957  if (Optional<StmtPoint> SP = Node->getLocationAs<StmtPoint>())
958  // See if we do not enter into another context.
959  if (SP->getStmt() == S && CurrentSFC == PredSFC)
960  break;
961 
962  CurrentSFC = PredSFC;
963  } while (Node->getStackFrame() == CurrentSFC);
964 
965  // Next, step over any post-statement checks.
966  while (Node && Node->getLocation().getAs<PostStmt>())
967  Node = Node->getFirstPred();
968  if (!Node)
969  return;
970 
971  // Finally, see if we inlined the call.
972  Optional<CallExitEnd> CEE = Node->getLocationAs<CallExitEnd>();
973  if (!CEE)
974  return;
975 
976  const StackFrameContext *CalleeContext = CEE->getCalleeContext();
977  if (CalleeContext->getCallSite() != S)
978  return;
979 
980  // Check the return value.
981  ProgramStateRef State = Node->getState();
982  SVal RetVal = Node->getSVal(S);
983 
984  // Handle cases where a reference is returned and then immediately used.
985  if (cast<Expr>(S)->isGLValue())
986  if (Optional<Loc> LValue = RetVal.getAs<Loc>())
987  RetVal = State->getSVal(*LValue);
988 
989  // See if the return value is NULL. If so, suppress the report.
990  AnalyzerOptions &Options = State->getAnalysisManager().options;
991 
992  bool EnableNullFPSuppression = false;
993  if (InEnableNullFPSuppression &&
994  Options.ShouldSuppressNullReturnPaths)
995  if (Optional<Loc> RetLoc = RetVal.getAs<Loc>())
996  EnableNullFPSuppression = State->isNull(*RetLoc).isConstrainedTrue();
997 
998  BR.addVisitor(std::make_unique<ReturnVisitor>(CalleeContext,
999  EnableNullFPSuppression,
1000  Options, TKind));
1001  }
1002 
1003  PathDiagnosticPieceRef visitNodeInitial(const ExplodedNode *N,
1004  BugReporterContext &BRC,
1005  PathSensitiveBugReport &BR) {
1006  // Only print a message at the interesting return statement.
1007  if (N->getLocationContext() != CalleeSFC)
1008  return nullptr;
1009 
1010  Optional<StmtPoint> SP = N->getLocationAs<StmtPoint>();
1011  if (!SP)
1012  return nullptr;
1013 
1014  const auto *Ret = dyn_cast<ReturnStmt>(SP->getStmt());
1015  if (!Ret)
1016  return nullptr;
1017 
1018  // Okay, we're at the right return statement, but do we have the return
1019  // value available?
1020  ProgramStateRef State = N->getState();
1021  SVal V = State->getSVal(Ret, CalleeSFC);
1022  if (V.isUnknownOrUndef())
1023  return nullptr;
1024 
1025  // Don't print any more notes after this one.
1026  Mode = Satisfied;
1027 
1028  const Expr *RetE = Ret->getRetValue();
1029  assert(RetE && "Tracking a return value for a void function");
1030 
1031  // Handle cases where a reference is returned and then immediately used.
1032  Optional<Loc> LValue;
1033  if (RetE->isGLValue()) {
1034  if ((LValue = V.getAs<Loc>())) {
1035  SVal RValue = State->getRawSVal(*LValue, RetE->getType());
1036  if (RValue.getAs<DefinedSVal>())
1037  V = RValue;
1038  }
1039  }
1040 
1041  // Ignore aggregate rvalues.
1042  if (V.getAs<nonloc::LazyCompoundVal>() ||
1043  V.getAs<nonloc::CompoundVal>())
1044  return nullptr;
1045 
1046  RetE = RetE->IgnoreParenCasts();
1047 
1048  // Let's track the return value.
1049  bugreporter::trackExpressionValue(
1050  N, RetE, BR, TKind, EnableNullFPSuppression);
1051 
1052  // Build an appropriate message based on the return value.
1053  SmallString<64> Msg;
1054  llvm::raw_svector_ostream Out(Msg);
1055 
1056  bool WouldEventBeMeaningless = false;
1057 
1058  if (State->isNull(V).isConstrainedTrue()) {
1059  if (V.getAs<Loc>()) {
1060 
1061  // If we have counter-suppression enabled, make sure we keep visiting
1062  // future nodes. We want to emit a path note as well, in case
1063  // the report is resurrected as valid later on.
1064  if (EnableNullFPSuppression &&
1065  Options.ShouldAvoidSuppressingNullArgumentPaths)
1066  Mode = MaybeUnsuppress;
1067 
1068  if (RetE->getType()->isObjCObjectPointerType()) {
1069  Out << "Returning nil";
1070  } else {
1071  Out << "Returning null pointer";
1072  }
1073  } else {
1074  Out << "Returning zero";
1075  }
1076 
1077  } else {
1078  if (auto CI = V.getAs<nonloc::ConcreteInt>()) {
1079  Out << "Returning the value " << CI->getValue();
1080  } else {
1081  // There is nothing interesting about returning a value, when it is
1082  // plain value without any constraints, and the function is guaranteed
1083  // to return that every time. We could use CFG::isLinear() here, but
1084  // constexpr branches are obvious to the compiler, not necesserily to
1085  // the programmer.
1086  if (N->getCFG().size() == 3)
1087  WouldEventBeMeaningless = true;
1088 
1089  if (V.getAs<Loc>())
1090  Out << "Returning pointer";
1091  else
1092  Out << "Returning value";
1093  }
1094  }
1095 
1096  if (LValue) {
1097  if (const MemRegion *MR = LValue->getAsRegion()) {
1098  if (MR->canPrintPretty()) {
1099  Out << " (reference to ";
1100  MR->printPretty(Out);
1101  Out << ")";
1102  }
1103  }
1104  } else {
1105  // FIXME: We should have a more generalized location printing mechanism.
1106  if (const auto *DR = dyn_cast<DeclRefExpr>(RetE))
1107  if (const auto *DD = dyn_cast<DeclaratorDecl>(DR->getDecl()))
1108  Out << " (loaded from '" << *DD << "')";
1109  }
1110 
1111  PathDiagnosticLocation L(Ret, BRC.getSourceManager(), CalleeSFC);
1112  if (!L.isValid() || !L.asLocation().isValid())
1113  return nullptr;
1114 
1115  if (TKind == bugreporter::TrackingKind::Condition)
1116  Out << WillBeUsedForACondition;
1117 
1118  auto EventPiece = std::make_shared<PathDiagnosticEventPiece>(L, Out.str());
1119 
1120  // If we determined that the note is meaningless, make it prunable, and
1121  // don't mark the stackframe interesting.
1122  if (WouldEventBeMeaningless)
1123  EventPiece->setPrunable(true);
1124  else
1125  BR.markInteresting(CalleeSFC);
1126 
1127  return EventPiece;
1128  }
1129 
1130  PathDiagnosticPieceRef visitNodeMaybeUnsuppress(const ExplodedNode *N,
1131  BugReporterContext &BRC,
1132  PathSensitiveBugReport &BR) {
1133  assert(Options.ShouldAvoidSuppressingNullArgumentPaths);
1134 
1135  // Are we at the entry node for this call?
1136  Optional<CallEnter> CE = N->getLocationAs<CallEnter>();
1137  if (!CE)
1138  return nullptr;
1139 
1140  if (CE->getCalleeContext() != CalleeSFC)
1141  return nullptr;
1142 
1143  Mode = Satisfied;
1144 
1145  // Don't automatically suppress a report if one of the arguments is
1146  // known to be a null pointer. Instead, start tracking /that/ null
1147  // value back to its origin.
1148  ProgramStateManager &StateMgr = BRC.getStateManager();
1149  CallEventManager &CallMgr = StateMgr.getCallEventManager();
1150 
1151  ProgramStateRef State = N->getState();
1152  CallEventRef<> Call = CallMgr.getCaller(CalleeSFC, State);
1153  for (unsigned I = 0, E = Call->getNumArgs(); I != E; ++I) {
1154  Optional<Loc> ArgV = Call->getArgSVal(I).getAs<Loc>();
1155  if (!ArgV)
1156  continue;
1157 
1158  const Expr *ArgE = Call->getArgExpr(I);
1159  if (!ArgE)
1160  continue;
1161 
1162  // Is it possible for this argument to be non-null?
1163  if (!State->isNull(*ArgV).isConstrainedTrue())
1164  continue;
1165 
1166  if (trackExpressionValue(N, ArgE, BR, TKind, EnableNullFPSuppression))
1167  ShouldInvalidate = false;
1168 
1169  // If we /can't/ track the null pointer, we should err on the side of
1170  // false negatives, and continue towards marking this report invalid.
1171  // (We will still look at the other arguments, though.)
1172  }
1173 
1174  return nullptr;
1175  }
1176 
1177  PathDiagnosticPieceRef VisitNode(const ExplodedNode *N,
1178  BugReporterContext &BRC,
1179  PathSensitiveBugReport &BR) override {
1180  switch (Mode) {
1181  case Initial:
1182  return visitNodeInitial(N, BRC, BR);
1183  case MaybeUnsuppress:
1184  return visitNodeMaybeUnsuppress(N, BRC, BR);
1185  case Satisfied:
1186  return nullptr;
1187  }
1188 
1189  llvm_unreachable("Invalid visit mode!");
1190  }
1191 
1192  void finalizeVisitor(BugReporterContext &, const ExplodedNode *,
1193  PathSensitiveBugReport &BR) override {
1194  if (EnableNullFPSuppression && ShouldInvalidate)
1195  BR.markInvalid(ReturnVisitor::getTag(), CalleeSFC);
1196  }
1197 };
1198 
1199 } // end of anonymous namespace
1200 
1201 //===----------------------------------------------------------------------===//
1202 // Implementation of FindLastStoreBRVisitor.
1203 //===----------------------------------------------------------------------===//
1204 
1205 void FindLastStoreBRVisitor::Profile(llvm::FoldingSetNodeID &ID) const {
1206  static int tag = 0;
1207  ID.AddPointer(&tag);
1208  ID.AddPointer(R);
1209  ID.Add(V);
1210  ID.AddInteger(static_cast<int>(TKind));
1211  ID.AddBoolean(EnableNullFPSuppression);
1212 }
1213 
1214 /// Returns true if \p N represents the DeclStmt declaring and initializing
1215 /// \p VR.
1216 static bool isInitializationOfVar(const ExplodedNode *N, const VarRegion *VR) {
1217  Optional<PostStmt> P = N->getLocationAs<PostStmt>();
1218  if (!P)
1219  return false;
1220 
1221  const DeclStmt *DS = P->getStmtAs<DeclStmt>();
1222  if (!DS)
1223  return false;
1224 
1225  if (DS->getSingleDecl() != VR->getDecl())
1226  return false;
1227 
1228  const MemSpaceRegion *VarSpace = VR->getMemorySpace();
1229  const auto *FrameSpace = dyn_cast<StackSpaceRegion>(VarSpace);
1230  if (!FrameSpace) {
1231  // If we ever directly evaluate global DeclStmts, this assertion will be
1232  // invalid, but this still seems preferable to silently accepting an
1233  // initialization that may be for a path-sensitive variable.
1234  assert(VR->getDecl()->isStaticLocal() && "non-static stackless VarRegion");
1235  return true;
1236  }
1237 
1238  assert(VR->getDecl()->hasLocalStorage());
1239  const LocationContext *LCtx = N->getLocationContext();
1240  return FrameSpace->getStackFrame() == LCtx->getStackFrame();
1241 }
1242 
1243 /// Show diagnostics for initializing or declaring a region \p R with a bad value.
1244 static void showBRDiagnostics(const char *action, llvm::raw_svector_ostream &os,
1245  const MemRegion *R, SVal V, const DeclStmt *DS) {
1246  if (R->canPrintPretty()) {
1247  R->printPretty(os);
1248  os << " ";
1249  }
1250 
1251  if (V.getAs<loc::ConcreteInt>()) {
1252  bool b = false;
1253  if (R->isBoundable()) {
1254  if (const auto *TR = dyn_cast<TypedValueRegion>(R)) {
1255  if (TR->getValueType()->isObjCObjectPointerType()) {
1256  os << action << "nil";
1257  b = true;
1258  }
1259  }
1260  }
1261  if (!b)
1262  os << action << "a null pointer value";
1263 
1264  } else if (auto CVal = V.getAs<nonloc::ConcreteInt>()) {
1265  os << action << CVal->getValue();
1266  } else if (DS) {
1267  if (V.isUndef()) {
1268  if (isa<VarRegion>(R)) {
1269  const auto *VD = cast<VarDecl>(DS->getSingleDecl());
1270  if (VD->getInit()) {
1271  os << (R->canPrintPretty() ? "initialized" : "Initializing")
1272  << " to a garbage value";
1273  } else {
1274  os << (R->canPrintPretty() ? "declared" : "Declaring")
1275  << " without an initial value";
1276  }
1277  }
1278  } else {
1279  os << (R->canPrintPretty() ? "initialized" : "Initialized")
1280  << " here";
1281  }
1282  }
1283 }
1284 
1285 /// Display diagnostics for passing bad region as a parameter.
1286 static void showBRParamDiagnostics(llvm::raw_svector_ostream& os,
1287  const VarRegion *VR,
1288  SVal V) {
1289  const auto *Param = cast<ParmVarDecl>(VR->getDecl());
1290 
1291  os << "Passing ";
1292 
1293  if (V.getAs<loc::ConcreteInt>()) {
1294  if (Param->getType()->isObjCObjectPointerType())
1295  os << "nil object reference";
1296  else
1297  os << "null pointer value";
1298  } else if (V.isUndef()) {
1299  os << "uninitialized value";
1300  } else if (auto CI = V.getAs<nonloc::ConcreteInt>()) {
1301  os << "the value " << CI->getValue();
1302  } else {
1303  os << "value";
1304  }
1305 
1306  // Printed parameter indexes are 1-based, not 0-based.
1307  unsigned Idx = Param->getFunctionScopeIndex() + 1;
1308  os << " via " << Idx << llvm::getOrdinalSuffix(Idx) << " parameter";
1309  if (VR->canPrintPretty()) {
1310  os << " ";
1311  VR->printPretty(os);
1312  }
1313 }
1314 
1315 /// Show default diagnostics for storing bad region.
1316 static void showBRDefaultDiagnostics(llvm::raw_svector_ostream &os,
1317  const MemRegion *R, SVal V) {
1318  if (V.getAs<loc::ConcreteInt>()) {
1319  bool b = false;
1320  if (R->isBoundable()) {
1321  if (const auto *TR = dyn_cast<TypedValueRegion>(R)) {
1322  if (TR->getValueType()->isObjCObjectPointerType()) {
1323  os << "nil object reference stored";
1324  b = true;
1325  }
1326  }
1327  }
1328  if (!b) {
1329  if (R->canPrintPretty())
1330  os << "Null pointer value stored";
1331  else
1332  os << "Storing null pointer value";
1333  }
1334 
1335  } else if (V.isUndef()) {
1336  if (R->canPrintPretty())
1337  os << "Uninitialized value stored";
1338  else
1339  os << "Storing uninitialized value";
1340 
1341  } else if (auto CV = V.getAs<nonloc::ConcreteInt>()) {
1342  if (R->canPrintPretty())
1343  os << "The value " << CV->getValue() << " is assigned";
1344  else
1345  os << "Assigning " << CV->getValue();
1346 
1347  } else {
1348  if (R->canPrintPretty())
1349  os << "Value assigned";
1350  else
1351  os << "Assigning value";
1352  }
1353 
1354  if (R->canPrintPretty()) {
1355  os << " to ";
1356  R->printPretty(os);
1357  }
1358 }
1359 
1361 FindLastStoreBRVisitor::VisitNode(const ExplodedNode *Succ,
1362  BugReporterContext &BRC,
1363  PathSensitiveBugReport &BR) {
1364  if (Satisfied)
1365  return nullptr;
1366 
1367  const ExplodedNode *StoreSite = nullptr;
1368  const ExplodedNode *Pred = Succ->getFirstPred();
1369  const Expr *InitE = nullptr;
1370  bool IsParam = false;
1371 
1372  // First see if we reached the declaration of the region.
1373  if (const auto *VR = dyn_cast<VarRegion>(R)) {
1374  if (isInitializationOfVar(Pred, VR)) {
1375  StoreSite = Pred;
1376  InitE = VR->getDecl()->getInit();
1377  }
1378  }
1379 
1380  // If this is a post initializer expression, initializing the region, we
1381  // should track the initializer expression.
1382  if (Optional<PostInitializer> PIP = Pred->getLocationAs<PostInitializer>()) {
1383  const MemRegion *FieldReg = (const MemRegion *)PIP->getLocationValue();
1384  if (FieldReg == R) {
1385  StoreSite = Pred;
1386  InitE = PIP->getInitializer()->getInit();
1387  }
1388  }
1389 
1390  // Otherwise, see if this is the store site:
1391  // (1) Succ has this binding and Pred does not, i.e. this is
1392  // where the binding first occurred.
1393  // (2) Succ has this binding and is a PostStore node for this region, i.e.
1394  // the same binding was re-assigned here.
1395  if (!StoreSite) {
1396  if (Succ->getState()->getSVal(R) != V)
1397  return nullptr;
1398 
1399  if (hasVisibleUpdate(Pred, Pred->getState()->getSVal(R), Succ, V)) {
1400  Optional<PostStore> PS = Succ->getLocationAs<PostStore>();
1401  if (!PS || PS->getLocationValue() != R)
1402  return nullptr;
1403  }
1404 
1405  StoreSite = Succ;
1406 
1407  // If this is an assignment expression, we can track the value
1408  // being assigned.
1409  if (Optional<PostStmt> P = Succ->getLocationAs<PostStmt>())
1410  if (const BinaryOperator *BO = P->getStmtAs<BinaryOperator>())
1411  if (BO->isAssignmentOp())
1412  InitE = BO->getRHS();
1413 
1414  // If this is a call entry, the variable should be a parameter.
1415  // FIXME: Handle CXXThisRegion as well. (This is not a priority because
1416  // 'this' should never be NULL, but this visitor isn't just for NULL and
1417  // UndefinedVal.)
1418  if (Optional<CallEnter> CE = Succ->getLocationAs<CallEnter>()) {
1419  if (const auto *VR = dyn_cast<VarRegion>(R)) {
1420 
1421  const auto *Param = cast<ParmVarDecl>(VR->getDecl());
1422 
1423  ProgramStateManager &StateMgr = BRC.getStateManager();
1424  CallEventManager &CallMgr = StateMgr.getCallEventManager();
1425 
1426  CallEventRef<> Call = CallMgr.getCaller(CE->getCalleeContext(),
1427  Succ->getState());
1428  InitE = Call->getArgExpr(Param->getFunctionScopeIndex());
1429  IsParam = true;
1430  }
1431  }
1432 
1433  // If this is a CXXTempObjectRegion, the Expr responsible for its creation
1434  // is wrapped inside of it.
1435  if (const auto *TmpR = dyn_cast<CXXTempObjectRegion>(R))
1436  InitE = TmpR->getExpr();
1437  }
1438 
1439  if (!StoreSite)
1440  return nullptr;
1441 
1442  Satisfied = true;
1443 
1444  // If we have an expression that provided the value, try to track where it
1445  // came from.
1446  if (InitE) {
1447  if (!IsParam)
1448  InitE = InitE->IgnoreParenCasts();
1449 
1450  bugreporter::trackExpressionValue(
1451  StoreSite, InitE, BR, TKind, EnableNullFPSuppression);
1452  }
1453 
1454  if (TKind == TrackingKind::Condition &&
1455  !OriginSFC->isParentOf(StoreSite->getStackFrame()))
1456  return nullptr;
1457 
1458  // Okay, we've found the binding. Emit an appropriate message.
1459  SmallString<256> sbuf;
1460  llvm::raw_svector_ostream os(sbuf);
1461 
1462  if (Optional<PostStmt> PS = StoreSite->getLocationAs<PostStmt>()) {
1463  const Stmt *S = PS->getStmt();
1464  const char *action = nullptr;
1465  const auto *DS = dyn_cast<DeclStmt>(S);
1466  const auto *VR = dyn_cast<VarRegion>(R);
1467 
1468  if (DS) {
1469  action = R->canPrintPretty() ? "initialized to " :
1470  "Initializing to ";
1471  } else if (isa<BlockExpr>(S)) {
1472  action = R->canPrintPretty() ? "captured by block as " :
1473  "Captured by block as ";
1474  if (VR) {
1475  // See if we can get the BlockVarRegion.
1476  ProgramStateRef State = StoreSite->getState();
1477  SVal V = StoreSite->getSVal(S);
1478  if (const auto *BDR =
1479  dyn_cast_or_null<BlockDataRegion>(V.getAsRegion())) {
1480  if (const VarRegion *OriginalR = BDR->getOriginalRegion(VR)) {
1481  if (auto KV = State->getSVal(OriginalR).getAs<KnownSVal>())
1482  BR.addVisitor(std::make_unique<FindLastStoreBRVisitor>(
1483  *KV, OriginalR, EnableNullFPSuppression, TKind, OriginSFC));
1484  }
1485  }
1486  }
1487  }
1488  if (action)
1489  showBRDiagnostics(action, os, R, V, DS);
1490 
1491  } else if (StoreSite->getLocation().getAs<CallEnter>()) {
1492  if (const auto *VR = dyn_cast<VarRegion>(R))
1493  showBRParamDiagnostics(os, VR, V);
1494  }
1495 
1496  if (os.str().empty())
1497  showBRDefaultDiagnostics(os, R, V);
1498 
1499  if (TKind == bugreporter::TrackingKind::Condition)
1501 
1502  // Construct a new PathDiagnosticPiece.
1503  ProgramPoint P = StoreSite->getLocation();
1504  PathDiagnosticLocation L;
1505  if (P.getAs<CallEnter>() && InitE)
1506  L = PathDiagnosticLocation(InitE, BRC.getSourceManager(),
1507  P.getLocationContext());
1508 
1509  if (!L.isValid() || !L.asLocation().isValid())
1510  L = PathDiagnosticLocation::create(P, BRC.getSourceManager());
1511 
1512  if (!L.isValid() || !L.asLocation().isValid())
1513  return nullptr;
1514 
1515  return std::make_shared<PathDiagnosticEventPiece>(L, os.str());
1516 }
1517 
1518 //===----------------------------------------------------------------------===//
1519 // Implementation of TrackConstraintBRVisitor.
1520 //===----------------------------------------------------------------------===//
1521 
1522 void TrackConstraintBRVisitor::Profile(llvm::FoldingSetNodeID &ID) const {
1523  static int tag = 0;
1524  ID.AddPointer(&tag);
1525  ID.AddBoolean(Assumption);
1526  ID.Add(Constraint);
1527 }
1528 
1529 /// Return the tag associated with this visitor. This tag will be used
1530 /// to make all PathDiagnosticPieces created by this visitor.
1531 const char *TrackConstraintBRVisitor::getTag() {
1532  return "TrackConstraintBRVisitor";
1533 }
1534 
1535 bool TrackConstraintBRVisitor::isUnderconstrained(const ExplodedNode *N) const {
1536  if (IsZeroCheck)
1537  return N->getState()->isNull(Constraint).isUnderconstrained();
1538  return (bool)N->getState()->assume(Constraint, !Assumption);
1539 }
1540 
1541 PathDiagnosticPieceRef TrackConstraintBRVisitor::VisitNode(
1542  const ExplodedNode *N, BugReporterContext &BRC, PathSensitiveBugReport &) {
1543  const ExplodedNode *PrevN = N->getFirstPred();
1544  if (IsSatisfied)
1545  return nullptr;
1546 
1547  // Start tracking after we see the first state in which the value is
1548  // constrained.
1549  if (!IsTrackingTurnedOn)
1550  if (!isUnderconstrained(N))
1551  IsTrackingTurnedOn = true;
1552  if (!IsTrackingTurnedOn)
1553  return nullptr;
1554 
1555  // Check if in the previous state it was feasible for this constraint
1556  // to *not* be true.
1557  if (isUnderconstrained(PrevN)) {
1558  IsSatisfied = true;
1559 
1560  // As a sanity check, make sure that the negation of the constraint
1561  // was infeasible in the current state. If it is feasible, we somehow
1562  // missed the transition point.
1563  assert(!isUnderconstrained(N));
1564 
1565  // We found the transition point for the constraint. We now need to
1566  // pretty-print the constraint. (work-in-progress)
1567  SmallString<64> sbuf;
1568  llvm::raw_svector_ostream os(sbuf);
1569 
1570  if (Constraint.getAs<Loc>()) {
1571  os << "Assuming pointer value is ";
1572  os << (Assumption ? "non-null" : "null");
1573  }
1574 
1575  if (os.str().empty())
1576  return nullptr;
1577 
1578  // Construct a new PathDiagnosticPiece.
1579  ProgramPoint P = N->getLocation();
1580  PathDiagnosticLocation L =
1581  PathDiagnosticLocation::create(P, BRC.getSourceManager());
1582  if (!L.isValid())
1583  return nullptr;
1584 
1585  auto X = std::make_shared<PathDiagnosticEventPiece>(L, os.str());
1586  X->setTag(getTag());
1587  return std::move(X);
1588  }
1589 
1590  return nullptr;
1591 }
1592 
1593 //===----------------------------------------------------------------------===//
1594 // Implementation of SuppressInlineDefensiveChecksVisitor.
1595 //===----------------------------------------------------------------------===//
1596 
1597 SuppressInlineDefensiveChecksVisitor::
1598 SuppressInlineDefensiveChecksVisitor(DefinedSVal Value, const ExplodedNode *N)
1599  : V(Value) {
1600  // Check if the visitor is disabled.
1601  AnalyzerOptions &Options = N->getState()->getAnalysisManager().options;
1602  if (!Options.ShouldSuppressInlinedDefensiveChecks)
1603  IsSatisfied = true;
1604 
1605  assert(N->getState()->isNull(V).isConstrainedTrue() &&
1606  "The visitor only tracks the cases where V is constrained to 0");
1607 }
1608 
1609 void SuppressInlineDefensiveChecksVisitor::Profile(
1610  llvm::FoldingSetNodeID &ID) const {
1611  static int id = 0;
1612  ID.AddPointer(&id);
1613  ID.Add(V);
1614 }
1615 
1616 const char *SuppressInlineDefensiveChecksVisitor::getTag() {
1617  return "IDCVisitor";
1618 }
1619 
1621 SuppressInlineDefensiveChecksVisitor::VisitNode(const ExplodedNode *Succ,
1622  BugReporterContext &BRC,
1623  PathSensitiveBugReport &BR) {
1624  const ExplodedNode *Pred = Succ->getFirstPred();
1625  if (IsSatisfied)
1626  return nullptr;
1627 
1628  // Start tracking after we see the first state in which the value is null.
1629  if (!IsTrackingTurnedOn)
1630  if (Succ->getState()->isNull(V).isConstrainedTrue())
1631  IsTrackingTurnedOn = true;
1632  if (!IsTrackingTurnedOn)
1633  return nullptr;
1634 
1635  // Check if in the previous state it was feasible for this value
1636  // to *not* be null.
1637  if (!Pred->getState()->isNull(V).isConstrainedTrue()) {
1638  IsSatisfied = true;
1639 
1640  assert(Succ->getState()->isNull(V).isConstrainedTrue());
1641 
1642  // Check if this is inlined defensive checks.
1643  const LocationContext *CurLC =Succ->getLocationContext();
1644  const LocationContext *ReportLC = BR.getErrorNode()->getLocationContext();
1645  if (CurLC != ReportLC && !CurLC->isParentOf(ReportLC)) {
1646  BR.markInvalid("Suppress IDC", CurLC);
1647  return nullptr;
1648  }
1649 
1650  // Treat defensive checks in function-like macros as if they were an inlined
1651  // defensive check. If the bug location is not in a macro and the
1652  // terminator for the current location is in a macro then suppress the
1653  // warning.
1654  auto BugPoint = BR.getErrorNode()->getLocation().getAs<StmtPoint>();
1655 
1656  if (!BugPoint)
1657  return nullptr;
1658 
1659  ProgramPoint CurPoint = Succ->getLocation();
1660  const Stmt *CurTerminatorStmt = nullptr;
1661  if (auto BE = CurPoint.getAs<BlockEdge>()) {
1662  CurTerminatorStmt = BE->getSrc()->getTerminator().getStmt();
1663  } else if (auto SP = CurPoint.getAs<StmtPoint>()) {
1664  const Stmt *CurStmt = SP->getStmt();
1665  if (!CurStmt->getBeginLoc().isMacroID())
1666  return nullptr;
1667 
1668  CFGStmtMap *Map = CurLC->getAnalysisDeclContext()->getCFGStmtMap();
1669  CurTerminatorStmt = Map->getBlock(CurStmt)->getTerminatorStmt();
1670  } else {
1671  return nullptr;
1672  }
1673 
1674  if (!CurTerminatorStmt)
1675  return nullptr;
1676 
1677  SourceLocation TerminatorLoc = CurTerminatorStmt->getBeginLoc();
1678  if (TerminatorLoc.isMacroID()) {
1679  SourceLocation BugLoc = BugPoint->getStmt()->getBeginLoc();
1680 
1681  // Suppress reports unless we are in that same macro.
1682  if (!BugLoc.isMacroID() ||
1683  getMacroName(BugLoc, BRC) != getMacroName(TerminatorLoc, BRC)) {
1684  BR.markInvalid("Suppress Macro IDC", CurLC);
1685  }
1686  return nullptr;
1687  }
1688  }
1689  return nullptr;
1690 }
1691 
1692 //===----------------------------------------------------------------------===//
1693 // TrackControlDependencyCondBRVisitor.
1694 //===----------------------------------------------------------------------===//
1695 
1696 namespace {
1697 /// Tracks the expressions that are a control dependency of the node that was
1698 /// supplied to the constructor.
1699 /// For example:
1700 ///
1701 /// cond = 1;
1702 /// if (cond)
1703 /// 10 / 0;
1704 ///
1705 /// An error is emitted at line 3. This visitor realizes that the branch
1706 /// on line 2 is a control dependency of line 3, and tracks it's condition via
1707 /// trackExpressionValue().
1708 class TrackControlDependencyCondBRVisitor final : public BugReporterVisitor {
1709  const ExplodedNode *Origin;
1710  ControlDependencyCalculator ControlDeps;
1711  llvm::SmallSet<const CFGBlock *, 32> VisitedBlocks;
1712 
1713 public:
1714  TrackControlDependencyCondBRVisitor(const ExplodedNode *O)
1715  : Origin(O), ControlDeps(&O->getCFG()) {}
1716 
1717  void Profile(llvm::FoldingSetNodeID &ID) const override {
1718  static int x = 0;
1719  ID.AddPointer(&x);
1720  }
1721 
1722  PathDiagnosticPieceRef VisitNode(const ExplodedNode *N,
1723  BugReporterContext &BRC,
1724  PathSensitiveBugReport &BR) override;
1725 };
1726 } // end of anonymous namespace
1727 
1728 static std::shared_ptr<PathDiagnosticEventPiece>
1730  const ExplodedNode *N,
1731  BugReporterContext &BRC) {
1732 
1733  if (BRC.getAnalyzerOptions().AnalysisDiagOpt == PD_NONE ||
1734  !BRC.getAnalyzerOptions().ShouldTrackConditionsDebug)
1735  return nullptr;
1736 
1737  std::string ConditionText = Lexer::getSourceText(
1739  BRC.getSourceManager(),
1740  BRC.getASTContext().getLangOpts());
1741 
1742  return std::make_shared<PathDiagnosticEventPiece>(
1744  Cond, BRC.getSourceManager(), N->getLocationContext()),
1745  (Twine() + "Tracking condition '" + ConditionText + "'").str());
1746 }
1747 
1748 static bool isAssertlikeBlock(const CFGBlock *B, ASTContext &Context) {
1749  if (B->succ_size() != 2)
1750  return false;
1751 
1752  const CFGBlock *Then = B->succ_begin()->getReachableBlock();
1753  const CFGBlock *Else = (B->succ_begin() + 1)->getReachableBlock();
1754 
1755  if (!Then || !Else)
1756  return false;
1757 
1758  if (Then->isInevitablySinking() != Else->isInevitablySinking())
1759  return true;
1760 
1761  // For the following condition the following CFG would be built:
1762  //
1763  // ------------->
1764  // / \
1765  // [B1] -> [B2] -> [B3] -> [sink]
1766  // assert(A && B || C); \ \
1767  // -----------> [go on with the execution]
1768  //
1769  // It so happens that CFGBlock::getTerminatorCondition returns 'A' for block
1770  // B1, 'A && B' for B2, and 'A && B || C' for B3. Let's check whether we
1771  // reached the end of the condition!
1772  if (const Stmt *ElseCond = Else->getTerminatorCondition())
1773  if (const auto *BinOp = dyn_cast<BinaryOperator>(ElseCond))
1774  if (BinOp->isLogicalOp())
1775  return isAssertlikeBlock(Else, Context);
1776 
1777  return false;
1778 }
1779 
1781 TrackControlDependencyCondBRVisitor::VisitNode(const ExplodedNode *N,
1782  BugReporterContext &BRC,
1783  PathSensitiveBugReport &BR) {
1784  // We can only reason about control dependencies within the same stack frame.
1785  if (Origin->getStackFrame() != N->getStackFrame())
1786  return nullptr;
1787 
1788  CFGBlock *NB = const_cast<CFGBlock *>(N->getCFGBlock());
1789 
1790  // Skip if we already inspected this block.
1791  if (!VisitedBlocks.insert(NB).second)
1792  return nullptr;
1793 
1794  CFGBlock *OriginB = const_cast<CFGBlock *>(Origin->getCFGBlock());
1795 
1796  // TODO: Cache CFGBlocks for each ExplodedNode.
1797  if (!OriginB || !NB)
1798  return nullptr;
1799 
1800  if (isAssertlikeBlock(NB, BRC.getASTContext()))
1801  return nullptr;
1802 
1803  if (ControlDeps.isControlDependent(OriginB, NB)) {
1804  // We don't really want to explain for range loops. Evidence suggests that
1805  // the only thing that leads to is the addition of calls to operator!=.
1806  if (llvm::isa_and_nonnull<CXXForRangeStmt>(NB->getTerminatorStmt()))
1807  return nullptr;
1808 
1809  if (const Expr *Condition = NB->getLastCondition()) {
1810  // Keeping track of the already tracked conditions on a visitor level
1811  // isn't sufficient, because a new visitor is created for each tracked
1812  // expression, hence the BugReport level set.
1813  if (BR.addTrackedCondition(N)) {
1814  bugreporter::trackExpressionValue(
1815  N, Condition, BR, bugreporter::TrackingKind::Condition,
1816  /*EnableNullFPSuppression=*/false);
1817  return constructDebugPieceForTrackedCondition(Condition, N, BRC);
1818  }
1819  }
1820  }
1821 
1822  return nullptr;
1823 }
1824 
1825 //===----------------------------------------------------------------------===//
1826 // Implementation of trackExpressionValue.
1827 //===----------------------------------------------------------------------===//
1828 
1829 static const MemRegion *getLocationRegionIfReference(const Expr *E,
1830  const ExplodedNode *N) {
1831  if (const auto *DR = dyn_cast<DeclRefExpr>(E)) {
1832  if (const auto *VD = dyn_cast<VarDecl>(DR->getDecl())) {
1833  if (!VD->getType()->isReferenceType())
1834  return nullptr;
1835  ProgramStateManager &StateMgr = N->getState()->getStateManager();
1836  MemRegionManager &MRMgr = StateMgr.getRegionManager();
1837  return MRMgr.getVarRegion(VD, N->getLocationContext());
1838  }
1839  }
1840 
1841  // FIXME: This does not handle other kinds of null references,
1842  // for example, references from FieldRegions:
1843  // struct Wrapper { int &ref; };
1844  // Wrapper w = { *(int *)0 };
1845  // w.ref = 1;
1846 
1847  return nullptr;
1848 }
1849 
1850 /// \return A subexpression of {@code Ex} which represents the
1851 /// expression-of-interest.
1852 static const Expr *peelOffOuterExpr(const Expr *Ex,
1853  const ExplodedNode *N) {
1854  Ex = Ex->IgnoreParenCasts();
1855  if (const auto *FE = dyn_cast<FullExpr>(Ex))
1856  return peelOffOuterExpr(FE->getSubExpr(), N);
1857  if (const auto *OVE = dyn_cast<OpaqueValueExpr>(Ex))
1858  return peelOffOuterExpr(OVE->getSourceExpr(), N);
1859  if (const auto *POE = dyn_cast<PseudoObjectExpr>(Ex)) {
1860  const auto *PropRef = dyn_cast<ObjCPropertyRefExpr>(POE->getSyntacticForm());
1861  if (PropRef && PropRef->isMessagingGetter()) {
1862  const Expr *GetterMessageSend =
1863  POE->getSemanticExpr(POE->getNumSemanticExprs() - 1);
1864  assert(isa<ObjCMessageExpr>(GetterMessageSend->IgnoreParenCasts()));
1865  return peelOffOuterExpr(GetterMessageSend, N);
1866  }
1867  }
1868 
1869  // Peel off the ternary operator.
1870  if (const auto *CO = dyn_cast<ConditionalOperator>(Ex)) {
1871  // Find a node where the branching occurred and find out which branch
1872  // we took (true/false) by looking at the ExplodedGraph.
1873  const ExplodedNode *NI = N;
1874  do {
1875  ProgramPoint ProgPoint = NI->getLocation();
1876  if (Optional<BlockEdge> BE = ProgPoint.getAs<BlockEdge>()) {
1877  const CFGBlock *srcBlk = BE->getSrc();
1878  if (const Stmt *term = srcBlk->getTerminatorStmt()) {
1879  if (term == CO) {
1880  bool TookTrueBranch = (*(srcBlk->succ_begin()) == BE->getDst());
1881  if (TookTrueBranch)
1882  return peelOffOuterExpr(CO->getTrueExpr(), N);
1883  else
1884  return peelOffOuterExpr(CO->getFalseExpr(), N);
1885  }
1886  }
1887  }
1888  NI = NI->getFirstPred();
1889  } while (NI);
1890  }
1891 
1892  if (auto *BO = dyn_cast<BinaryOperator>(Ex))
1893  if (const Expr *SubEx = peelOffPointerArithmetic(BO))
1894  return peelOffOuterExpr(SubEx, N);
1895 
1896  if (auto *UO = dyn_cast<UnaryOperator>(Ex)) {
1897  if (UO->getOpcode() == UO_LNot)
1898  return peelOffOuterExpr(UO->getSubExpr(), N);
1899 
1900  // FIXME: There's a hack in our Store implementation that always computes
1901  // field offsets around null pointers as if they are always equal to 0.
1902  // The idea here is to report accesses to fields as null dereferences
1903  // even though the pointer value that's being dereferenced is actually
1904  // the offset of the field rather than exactly 0.
1905  // See the FIXME in StoreManager's getLValueFieldOrIvar() method.
1906  // This code interacts heavily with this hack; otherwise the value
1907  // would not be null at all for most fields, so we'd be unable to track it.
1908  if (UO->getOpcode() == UO_AddrOf && UO->getSubExpr()->isLValue())
1909  if (const Expr *DerefEx = bugreporter::getDerefExpr(UO->getSubExpr()))
1910  return peelOffOuterExpr(DerefEx, N);
1911  }
1912 
1913  return Ex;
1914 }
1915 
1916 /// Find the ExplodedNode where the lvalue (the value of 'Ex')
1917 /// was computed.
1918 static const ExplodedNode* findNodeForExpression(const ExplodedNode *N,
1919  const Expr *Inner) {
1920  while (N) {
1921  if (N->getStmtForDiagnostics() == Inner)
1922  return N;
1923  N = N->getFirstPred();
1924  }
1925  return N;
1926 }
1927 
1928 bool bugreporter::trackExpressionValue(const ExplodedNode *InputNode,
1929  const Expr *E,
1930  PathSensitiveBugReport &report,
1931  bugreporter::TrackingKind TKind,
1932  bool EnableNullFPSuppression) {
1933 
1934  if (!E || !InputNode)
1935  return false;
1936 
1937  const Expr *Inner = peelOffOuterExpr(E, InputNode);
1938  const ExplodedNode *LVNode = findNodeForExpression(InputNode, Inner);
1939  if (!LVNode)
1940  return false;
1941 
1942  ProgramStateRef LVState = LVNode->getState();
1943  const StackFrameContext *SFC = LVNode->getStackFrame();
1944 
1945  // We only track expressions if we believe that they are important. Chances
1946  // are good that control dependencies to the tracking point are also improtant
1947  // because of this, let's explain why we believe control reached this point.
1948  // TODO: Shouldn't we track control dependencies of every bug location, rather
1949  // than only tracked expressions?
1950  if (LVState->getAnalysisManager().getAnalyzerOptions().ShouldTrackConditions)
1951  report.addVisitor(std::make_unique<TrackControlDependencyCondBRVisitor>(
1952  InputNode));
1953 
1954  // The message send could be nil due to the receiver being nil.
1955  // At this point in the path, the receiver should be live since we are at the
1956  // message send expr. If it is nil, start tracking it.
1957  if (const Expr *Receiver = NilReceiverBRVisitor::getNilReceiver(Inner, LVNode))
1958  trackExpressionValue(
1959  LVNode, Receiver, report, TKind, EnableNullFPSuppression);
1960 
1961  // Track the index if this is an array subscript.
1962  if (const auto *Arr = dyn_cast<ArraySubscriptExpr>(Inner))
1963  trackExpressionValue(
1964  LVNode, Arr->getIdx(), report, TKind, /*EnableNullFPSuppression*/false);
1965 
1966  // See if the expression we're interested refers to a variable.
1967  // If so, we can track both its contents and constraints on its value.
1969  SVal LVal = LVNode->getSVal(Inner);
1970 
1971  const MemRegion *RR = getLocationRegionIfReference(Inner, LVNode);
1972  bool LVIsNull = LVState->isNull(LVal).isConstrainedTrue();
1973 
1974  // If this is a C++ reference to a null pointer, we are tracking the
1975  // pointer. In addition, we should find the store at which the reference
1976  // got initialized.
1977  if (RR && !LVIsNull)
1978  if (auto KV = LVal.getAs<KnownSVal>())
1979  report.addVisitor(std::make_unique<FindLastStoreBRVisitor>(
1980  *KV, RR, EnableNullFPSuppression, TKind, SFC));
1981 
1982  // In case of C++ references, we want to differentiate between a null
1983  // reference and reference to null pointer.
1984  // If the LVal is null, check if we are dealing with null reference.
1985  // For those, we want to track the location of the reference.
1986  const MemRegion *R = (RR && LVIsNull) ? RR :
1987  LVNode->getSVal(Inner).getAsRegion();
1988 
1989  if (R) {
1990 
1991  // Mark both the variable region and its contents as interesting.
1992  SVal V = LVState->getRawSVal(loc::MemRegionVal(R));
1993  report.addVisitor(
1994  std::make_unique<NoStoreFuncVisitor>(cast<SubRegion>(R), TKind));
1995 
1996  MacroNullReturnSuppressionVisitor::addMacroVisitorIfNecessary(
1997  LVNode, R, EnableNullFPSuppression, report, V);
1998 
1999  report.markInteresting(V, TKind);
2000  report.addVisitor(std::make_unique<UndefOrNullArgVisitor>(R));
2001 
2002  // If the contents are symbolic and null, find out when they became null.
2003  if (V.getAsLocSymbol(/*IncludeBaseRegions=*/true))
2004  if (LVState->isNull(V).isConstrainedTrue())
2005  report.addVisitor(std::make_unique<TrackConstraintBRVisitor>(
2006  V.castAs<DefinedSVal>(), false));
2007 
2008  // Add visitor, which will suppress inline defensive checks.
2009  if (auto DV = V.getAs<DefinedSVal>())
2010  if (!DV->isZeroConstant() && LVState->isNull(*DV).isConstrainedTrue() &&
2011  EnableNullFPSuppression)
2012  report.addVisitor(
2013  std::make_unique<SuppressInlineDefensiveChecksVisitor>(*DV,
2014  LVNode));
2015 
2016  if (auto KV = V.getAs<KnownSVal>())
2017  report.addVisitor(std::make_unique<FindLastStoreBRVisitor>(
2018  *KV, R, EnableNullFPSuppression, TKind, SFC));
2019  return true;
2020  }
2021  }
2022 
2023  // If the expression is not an "lvalue expression", we can still
2024  // track the constraints on its contents.
2025  SVal V = LVState->getSValAsScalarOrLoc(Inner, LVNode->getLocationContext());
2026 
2027  ReturnVisitor::addVisitorIfNecessary(
2028  LVNode, Inner, report, EnableNullFPSuppression, TKind);
2029 
2030  // Is it a symbolic value?
2031  if (auto L = V.getAs<loc::MemRegionVal>()) {
2032  report.addVisitor(std::make_unique<UndefOrNullArgVisitor>(L->getRegion()));
2033 
2034  // FIXME: this is a hack for fixing a later crash when attempting to
2035  // dereference a void* pointer.
2036  // We should not try to dereference pointers at all when we don't care
2037  // what is written inside the pointer.
2038  bool CanDereference = true;
2039  if (const auto *SR = L->getRegionAs<SymbolicRegion>()) {
2040  if (SR->getSymbol()->getType()->getPointeeType()->isVoidType())
2041  CanDereference = false;
2042  } else if (L->getRegionAs<AllocaRegion>())
2043  CanDereference = false;
2044 
2045  // At this point we are dealing with the region's LValue.
2046  // However, if the rvalue is a symbolic region, we should track it as well.
2047  // Try to use the correct type when looking up the value.
2048  SVal RVal;
2050  RVal = LVState->getRawSVal(L.getValue(), Inner->getType());
2051  else if (CanDereference)
2052  RVal = LVState->getSVal(L->getRegion());
2053 
2054  if (CanDereference)
2055  if (auto KV = RVal.getAs<KnownSVal>())
2056  report.addVisitor(std::make_unique<FindLastStoreBRVisitor>(
2057  *KV, L->getRegion(), EnableNullFPSuppression, TKind, SFC));
2058 
2059  const MemRegion *RegionRVal = RVal.getAsRegion();
2060  if (RegionRVal && isa<SymbolicRegion>(RegionRVal)) {
2061  report.markInteresting(RegionRVal, TKind);
2062  report.addVisitor(std::make_unique<TrackConstraintBRVisitor>(
2063  loc::MemRegionVal(RegionRVal), /*assumption=*/false));
2064  }
2065  }
2066  return true;
2067 }
2068 
2069 //===----------------------------------------------------------------------===//
2070 // Implementation of NulReceiverBRVisitor.
2071 //===----------------------------------------------------------------------===//
2072 
2073 const Expr *NilReceiverBRVisitor::getNilReceiver(const Stmt *S,
2074  const ExplodedNode *N) {
2075  const auto *ME = dyn_cast<ObjCMessageExpr>(S);
2076  if (!ME)
2077  return nullptr;
2078  if (const Expr *Receiver = ME->getInstanceReceiver()) {
2079  ProgramStateRef state = N->getState();
2080  SVal V = N->getSVal(Receiver);
2081  if (state->isNull(V).isConstrainedTrue())
2082  return Receiver;
2083  }
2084  return nullptr;
2085 }
2086 
2088 NilReceiverBRVisitor::VisitNode(const ExplodedNode *N, BugReporterContext &BRC,
2089  PathSensitiveBugReport &BR) {
2090  Optional<PreStmt> P = N->getLocationAs<PreStmt>();
2091  if (!P)
2092  return nullptr;
2093 
2094  const Stmt *S = P->getStmt();
2095  const Expr *Receiver = getNilReceiver(S, N);
2096  if (!Receiver)
2097  return nullptr;
2098 
2100  llvm::raw_svector_ostream OS(Buf);
2101 
2102  if (const auto *ME = dyn_cast<ObjCMessageExpr>(S)) {
2103  OS << "'";
2104  ME->getSelector().print(OS);
2105  OS << "' not called";
2106  }
2107  else {
2108  OS << "No method is called";
2109  }
2110  OS << " because the receiver is nil";
2111 
2112  // The receiver was nil, and hence the method was skipped.
2113  // Register a BugReporterVisitor to issue a message telling us how
2114  // the receiver was null.
2115  bugreporter::trackExpressionValue(
2116  N, Receiver, BR, bugreporter::TrackingKind::Thorough,
2117  /*EnableNullFPSuppression*/ false);
2118  // Issue a message saying that the method was skipped.
2119  PathDiagnosticLocation L(Receiver, BRC.getSourceManager(),
2120  N->getLocationContext());
2121  return std::make_shared<PathDiagnosticEventPiece>(L, OS.str());
2122 }
2123 
2124 //===----------------------------------------------------------------------===//
2125 // Visitor that tries to report interesting diagnostics from conditions.
2126 //===----------------------------------------------------------------------===//
2127 
2128 /// Return the tag associated with this visitor. This tag will be used
2129 /// to make all PathDiagnosticPieces created by this visitor.
2130 const char *ConditionBRVisitor::getTag() { return "ConditionBRVisitor"; }
2131 
2133 ConditionBRVisitor::VisitNode(const ExplodedNode *N, BugReporterContext &BRC,
2134  PathSensitiveBugReport &BR) {
2135  auto piece = VisitNodeImpl(N, BRC, BR);
2136  if (piece) {
2137  piece->setTag(getTag());
2138  if (auto *ev = dyn_cast<PathDiagnosticEventPiece>(piece.get()))
2139  ev->setPrunable(true, /* override */ false);
2140  }
2141  return piece;
2142 }
2143 
2145 ConditionBRVisitor::VisitNodeImpl(const ExplodedNode *N,
2146  BugReporterContext &BRC,
2147  PathSensitiveBugReport &BR) {
2148  ProgramPoint ProgPoint = N->getLocation();
2149  const std::pair<const ProgramPointTag *, const ProgramPointTag *> &Tags =
2151 
2152  // If an assumption was made on a branch, it should be caught
2153  // here by looking at the state transition.
2154  if (Optional<BlockEdge> BE = ProgPoint.getAs<BlockEdge>()) {
2155  const CFGBlock *SrcBlock = BE->getSrc();
2156  if (const Stmt *Term = SrcBlock->getTerminatorStmt()) {
2157  // If the tag of the previous node is 'Eagerly Assume...' the current
2158  // 'BlockEdge' has the same constraint information. We do not want to
2159  // report the value as it is just an assumption on the predecessor node
2160  // which will be caught in the next VisitNode() iteration as a 'PostStmt'.
2161  const ProgramPointTag *PreviousNodeTag =
2162  N->getFirstPred()->getLocation().getTag();
2163  if (PreviousNodeTag == Tags.first || PreviousNodeTag == Tags.second)
2164  return nullptr;
2165 
2166  return VisitTerminator(Term, N, SrcBlock, BE->getDst(), BR, BRC);
2167  }
2168  return nullptr;
2169  }
2170 
2171  if (Optional<PostStmt> PS = ProgPoint.getAs<PostStmt>()) {
2172  const ProgramPointTag *CurrentNodeTag = PS->getTag();
2173  if (CurrentNodeTag != Tags.first && CurrentNodeTag != Tags.second)
2174  return nullptr;
2175 
2176  bool TookTrue = CurrentNodeTag == Tags.first;
2177  return VisitTrueTest(cast<Expr>(PS->getStmt()), BRC, BR, N, TookTrue);
2178  }
2179 
2180  return nullptr;
2181 }
2182 
2183 PathDiagnosticPieceRef ConditionBRVisitor::VisitTerminator(
2184  const Stmt *Term, const ExplodedNode *N, const CFGBlock *srcBlk,
2185  const CFGBlock *dstBlk, PathSensitiveBugReport &R,
2186  BugReporterContext &BRC) {
2187  const Expr *Cond = nullptr;
2188 
2189  // In the code below, Term is a CFG terminator and Cond is a branch condition
2190  // expression upon which the decision is made on this terminator.
2191  //
2192  // For example, in "if (x == 0)", the "if (x == 0)" statement is a terminator,
2193  // and "x == 0" is the respective condition.
2194  //
2195  // Another example: in "if (x && y)", we've got two terminators and two
2196  // conditions due to short-circuit nature of operator "&&":
2197  // 1. The "if (x && y)" statement is a terminator,
2198  // and "y" is the respective condition.
2199  // 2. Also "x && ..." is another terminator,
2200  // and "x" is its condition.
2201 
2202  switch (Term->getStmtClass()) {
2203  // FIXME: Stmt::SwitchStmtClass is worth handling, however it is a bit
2204  // more tricky because there are more than two branches to account for.
2205  default:
2206  return nullptr;
2207  case Stmt::IfStmtClass:
2208  Cond = cast<IfStmt>(Term)->getCond();
2209  break;
2210  case Stmt::ConditionalOperatorClass:
2211  Cond = cast<ConditionalOperator>(Term)->getCond();
2212  break;
2213  case Stmt::BinaryOperatorClass:
2214  // When we encounter a logical operator (&& or ||) as a CFG terminator,
2215  // then the condition is actually its LHS; otherwise, we'd encounter
2216  // the parent, such as if-statement, as a terminator.
2217  const auto *BO = cast<BinaryOperator>(Term);
2218  assert(BO->isLogicalOp() &&
2219  "CFG terminator is not a short-circuit operator!");
2220  Cond = BO->getLHS();
2221  break;
2222  }
2223 
2224  Cond = Cond->IgnoreParens();
2225 
2226  // However, when we encounter a logical operator as a branch condition,
2227  // then the condition is actually its RHS, because LHS would be
2228  // the condition for the logical operator terminator.
2229  while (const auto *InnerBO = dyn_cast<BinaryOperator>(Cond)) {
2230  if (!InnerBO->isLogicalOp())
2231  break;
2232  Cond = InnerBO->getRHS()->IgnoreParens();
2233  }
2234 
2235  assert(Cond);
2236  assert(srcBlk->succ_size() == 2);
2237  const bool TookTrue = *(srcBlk->succ_begin()) == dstBlk;
2238  return VisitTrueTest(Cond, BRC, R, N, TookTrue);
2239 }
2240 
2242 ConditionBRVisitor::VisitTrueTest(const Expr *Cond, BugReporterContext &BRC,
2243  PathSensitiveBugReport &R,
2244  const ExplodedNode *N, bool TookTrue) {
2245  ProgramStateRef CurrentState = N->getState();
2246  ProgramStateRef PrevState = N->getFirstPred()->getState();
2247  const LocationContext *LCtx = N->getLocationContext();
2248 
2249  // If the constraint information is changed between the current and the
2250  // previous program state we assuming the newly seen constraint information.
2251  // If we cannot evaluate the condition (and the constraints are the same)
2252  // the analyzer has no information about the value and just assuming it.
2253  bool IsAssuming =
2254  !BRC.getStateManager().haveEqualConstraints(CurrentState, PrevState) ||
2255  CurrentState->getSVal(Cond, LCtx).isUnknownOrUndef();
2256 
2257  // These will be modified in code below, but we need to preserve the original
2258  // values in case we want to throw the generic message.
2259  const Expr *CondTmp = Cond;
2260  bool TookTrueTmp = TookTrue;
2261 
2262  while (true) {
2263  CondTmp = CondTmp->IgnoreParenCasts();
2264  switch (CondTmp->getStmtClass()) {
2265  default:
2266  break;
2267  case Stmt::BinaryOperatorClass:
2268  if (auto P = VisitTrueTest(Cond, cast<BinaryOperator>(CondTmp),
2269  BRC, R, N, TookTrueTmp, IsAssuming))
2270  return P;
2271  break;
2272  case Stmt::DeclRefExprClass:
2273  if (auto P = VisitTrueTest(Cond, cast<DeclRefExpr>(CondTmp),
2274  BRC, R, N, TookTrueTmp, IsAssuming))
2275  return P;
2276  break;
2277  case Stmt::MemberExprClass:
2278  if (auto P = VisitTrueTest(Cond, cast<MemberExpr>(CondTmp),
2279  BRC, R, N, TookTrueTmp, IsAssuming))
2280  return P;
2281  break;
2282  case Stmt::UnaryOperatorClass: {
2283  const auto *UO = cast<UnaryOperator>(CondTmp);
2284  if (UO->getOpcode() == UO_LNot) {
2285  TookTrueTmp = !TookTrueTmp;
2286  CondTmp = UO->getSubExpr();
2287  continue;
2288  }
2289  break;
2290  }
2291  }
2292  break;
2293  }
2294 
2295  // Condition too complex to explain? Just say something so that the user
2296  // knew we've made some path decision at this point.
2297  // If it is too complex and we know the evaluation of the condition do not
2298  // repeat the note from 'BugReporter.cpp'
2299  if (!IsAssuming)
2300  return nullptr;
2301 
2302  PathDiagnosticLocation Loc(Cond, BRC.getSourceManager(), LCtx);
2303  if (!Loc.isValid() || !Loc.asLocation().isValid())
2304  return nullptr;
2305 
2306  return std::make_shared<PathDiagnosticEventPiece>(
2307  Loc, TookTrue ? GenericTrueMessage : GenericFalseMessage);
2308 }
2309 
2310 bool ConditionBRVisitor::patternMatch(const Expr *Ex,
2311  const Expr *ParentEx,
2312  raw_ostream &Out,
2313  BugReporterContext &BRC,
2314  PathSensitiveBugReport &report,
2315  const ExplodedNode *N,
2316  Optional<bool> &prunable,
2317  bool IsSameFieldName) {
2318  const Expr *OriginalExpr = Ex;
2319  Ex = Ex->IgnoreParenCasts();
2320 
2321  if (isa<GNUNullExpr>(Ex) || isa<ObjCBoolLiteralExpr>(Ex) ||
2322  isa<CXXBoolLiteralExpr>(Ex) || isa<IntegerLiteral>(Ex) ||
2323  isa<FloatingLiteral>(Ex)) {
2324  // Use heuristics to determine if the expression is a macro
2325  // expanding to a literal and if so, use the macro's name.
2326  SourceLocation BeginLoc = OriginalExpr->getBeginLoc();
2327  SourceLocation EndLoc = OriginalExpr->getEndLoc();
2328  if (BeginLoc.isMacroID() && EndLoc.isMacroID()) {
2329  const SourceManager &SM = BRC.getSourceManager();
2330  const LangOptions &LO = BRC.getASTContext().getLangOpts();
2331  if (Lexer::isAtStartOfMacroExpansion(BeginLoc, SM, LO) &&
2332  Lexer::isAtEndOfMacroExpansion(EndLoc, SM, LO)) {
2333  CharSourceRange R = Lexer::getAsCharRange({BeginLoc, EndLoc}, SM, LO);
2334  Out << Lexer::getSourceText(R, SM, LO);
2335  return false;
2336  }
2337  }
2338  }
2339 
2340  if (const auto *DR = dyn_cast<DeclRefExpr>(Ex)) {
2341  const bool quotes = isa<VarDecl>(DR->getDecl());
2342  if (quotes) {
2343  Out << '\'';
2344  const LocationContext *LCtx = N->getLocationContext();
2345  const ProgramState *state = N->getState().get();
2346  if (const MemRegion *R = state->getLValue(cast<VarDecl>(DR->getDecl()),
2347  LCtx).getAsRegion()) {
2348  if (report.isInteresting(R))
2349  prunable = false;
2350  else {
2351  const ProgramState *state = N->getState().get();
2352  SVal V = state->getSVal(R);
2353  if (report.isInteresting(V))
2354  prunable = false;
2355  }
2356  }
2357  }
2358  Out << DR->getDecl()->getDeclName().getAsString();
2359  if (quotes)
2360  Out << '\'';
2361  return quotes;
2362  }
2363 
2364  if (const auto *IL = dyn_cast<IntegerLiteral>(Ex)) {
2365  QualType OriginalTy = OriginalExpr->getType();
2366  if (OriginalTy->isPointerType()) {
2367  if (IL->getValue() == 0) {
2368  Out << "null";
2369  return false;
2370  }
2371  }
2372  else if (OriginalTy->isObjCObjectPointerType()) {
2373  if (IL->getValue() == 0) {
2374  Out << "nil";
2375  return false;
2376  }
2377  }
2378 
2379  Out << IL->getValue();
2380  return false;
2381  }
2382 
2383  if (const auto *ME = dyn_cast<MemberExpr>(Ex)) {
2384  if (!IsSameFieldName)
2385  Out << "field '" << ME->getMemberDecl()->getName() << '\'';
2386  else
2387  Out << '\''
2390  BRC.getSourceManager(), BRC.getASTContext().getLangOpts(), 0)
2391  << '\'';
2392  }
2393 
2394  return false;
2395 }
2396 
2397 PathDiagnosticPieceRef ConditionBRVisitor::VisitTrueTest(
2398  const Expr *Cond, const BinaryOperator *BExpr, BugReporterContext &BRC,
2399  PathSensitiveBugReport &R, const ExplodedNode *N, bool TookTrue,
2400  bool IsAssuming) {
2401  bool shouldInvert = false;
2402  Optional<bool> shouldPrune;
2403 
2404  // Check if the field name of the MemberExprs is ambiguous. Example:
2405  // " 'a.d' is equal to 'h.d' " in 'test/Analysis/null-deref-path-notes.cpp'.
2406  bool IsSameFieldName = false;
2407  const auto *LhsME = dyn_cast<MemberExpr>(BExpr->getLHS()->IgnoreParenCasts());
2408  const auto *RhsME = dyn_cast<MemberExpr>(BExpr->getRHS()->IgnoreParenCasts());
2409 
2410  if (LhsME && RhsME)
2411  IsSameFieldName =
2412  LhsME->getMemberDecl()->getName() == RhsME->getMemberDecl()->getName();
2413 
2414  SmallString<128> LhsString, RhsString;
2415  {
2416  llvm::raw_svector_ostream OutLHS(LhsString), OutRHS(RhsString);
2417  const bool isVarLHS = patternMatch(BExpr->getLHS(), BExpr, OutLHS, BRC, R,
2418  N, shouldPrune, IsSameFieldName);
2419  const bool isVarRHS = patternMatch(BExpr->getRHS(), BExpr, OutRHS, BRC, R,
2420  N, shouldPrune, IsSameFieldName);
2421 
2422  shouldInvert = !isVarLHS && isVarRHS;
2423  }
2424 
2425  BinaryOperator::Opcode Op = BExpr->getOpcode();
2426 
2428  // For assignment operators, all that we care about is that the LHS
2429  // evaluates to "true" or "false".
2430  return VisitConditionVariable(LhsString, BExpr->getLHS(), BRC, R, N,
2431  TookTrue);
2432  }
2433 
2434  // For non-assignment operations, we require that we can understand
2435  // both the LHS and RHS.
2436  if (LhsString.empty() || RhsString.empty() ||
2437  !BinaryOperator::isComparisonOp(Op) || Op == BO_Cmp)
2438  return nullptr;
2439 
2440  // Should we invert the strings if the LHS is not a variable name?
2441  SmallString<256> buf;
2442  llvm::raw_svector_ostream Out(buf);
2443  Out << (IsAssuming ? "Assuming " : "")
2444  << (shouldInvert ? RhsString : LhsString) << " is ";
2445 
2446  // Do we need to invert the opcode?
2447  if (shouldInvert)
2448  switch (Op) {
2449  default: break;
2450  case BO_LT: Op = BO_GT; break;
2451  case BO_GT: Op = BO_LT; break;
2452  case BO_LE: Op = BO_GE; break;
2453  case BO_GE: Op = BO_LE; break;
2454  }
2455 
2456  if (!TookTrue)
2457  switch (Op) {
2458  case BO_EQ: Op = BO_NE; break;
2459  case BO_NE: Op = BO_EQ; break;
2460  case BO_LT: Op = BO_GE; break;
2461  case BO_GT: Op = BO_LE; break;
2462  case BO_LE: Op = BO_GT; break;
2463  case BO_GE: Op = BO_LT; break;
2464  default:
2465  return nullptr;
2466  }
2467 
2468  switch (Op) {
2469  case BO_EQ:
2470  Out << "equal to ";
2471  break;
2472  case BO_NE:
2473  Out << "not equal to ";
2474  break;
2475  default:
2476  Out << BinaryOperator::getOpcodeStr(Op) << ' ';
2477  break;
2478  }
2479 
2480  Out << (shouldInvert ? LhsString : RhsString);
2481  const LocationContext *LCtx = N->getLocationContext();
2482  const SourceManager &SM = BRC.getSourceManager();
2483 
2484  if (isVarAnInterestingCondition(BExpr->getLHS(), N, &R) ||
2485  isVarAnInterestingCondition(BExpr->getRHS(), N, &R))
2486  Out << WillBeUsedForACondition;
2487 
2488  // Convert 'field ...' to 'Field ...' if it is a MemberExpr.
2489  std::string Message = Out.str();
2490  Message[0] = toupper(Message[0]);
2491 
2492  // If we know the value create a pop-up note to the value part of 'BExpr'.
2493  if (!IsAssuming) {
2494  PathDiagnosticLocation Loc;
2495  if (!shouldInvert) {
2496  if (LhsME && LhsME->getMemberLoc().isValid())
2497  Loc = PathDiagnosticLocation(LhsME->getMemberLoc(), SM);
2498  else
2499  Loc = PathDiagnosticLocation(BExpr->getLHS(), SM, LCtx);
2500  } else {
2501  if (RhsME && RhsME->getMemberLoc().isValid())
2502  Loc = PathDiagnosticLocation(RhsME->getMemberLoc(), SM);
2503  else
2504  Loc = PathDiagnosticLocation(BExpr->getRHS(), SM, LCtx);
2505  }
2506 
2507  return std::make_shared<PathDiagnosticPopUpPiece>(Loc, Message);
2508  }
2509 
2510  PathDiagnosticLocation Loc(Cond, SM, LCtx);
2511  auto event = std::make_shared<PathDiagnosticEventPiece>(Loc, Message);
2512  if (shouldPrune.hasValue())
2513  event->setPrunable(shouldPrune.getValue());
2514  return event;
2515 }
2516 
2517 PathDiagnosticPieceRef ConditionBRVisitor::VisitConditionVariable(
2518  StringRef LhsString, const Expr *CondVarExpr, BugReporterContext &BRC,
2519  PathSensitiveBugReport &report, const ExplodedNode *N, bool TookTrue) {
2520  // FIXME: If there's already a constraint tracker for this variable,
2521  // we shouldn't emit anything here (c.f. the double note in
2522  // test/Analysis/inlining/path-notes.c)
2523  SmallString<256> buf;
2524  llvm::raw_svector_ostream Out(buf);
2525  Out << "Assuming " << LhsString << " is ";
2526 
2527  if (!printValue(CondVarExpr, Out, N, TookTrue, /*IsAssuming=*/true))
2528  return nullptr;
2529 
2530  const LocationContext *LCtx = N->getLocationContext();
2531  PathDiagnosticLocation Loc(CondVarExpr, BRC.getSourceManager(), LCtx);
2532 
2533  if (isVarAnInterestingCondition(CondVarExpr, N, &report))
2534  Out << WillBeUsedForACondition;
2535 
2536  auto event = std::make_shared<PathDiagnosticEventPiece>(Loc, Out.str());
2537 
2538  if (isInterestingExpr(CondVarExpr, N, &report))
2539  event->setPrunable(false);
2540 
2541  return event;
2542 }
2543 
2544 PathDiagnosticPieceRef ConditionBRVisitor::VisitTrueTest(
2545  const Expr *Cond, const DeclRefExpr *DRE, BugReporterContext &BRC,
2546  PathSensitiveBugReport &report, const ExplodedNode *N, bool TookTrue,
2547  bool IsAssuming) {
2548  const auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
2549  if (!VD)
2550  return nullptr;
2551 
2552  SmallString<256> Buf;
2553  llvm::raw_svector_ostream Out(Buf);
2554 
2555  Out << (IsAssuming ? "Assuming '" : "'") << VD->getDeclName() << "' is ";
2556 
2557  if (!printValue(DRE, Out, N, TookTrue, IsAssuming))
2558  return nullptr;
2559 
2560  const LocationContext *LCtx = N->getLocationContext();
2561 
2562  if (isVarAnInterestingCondition(DRE, N, &report))
2563  Out << WillBeUsedForACondition;
2564 
2565  // If we know the value create a pop-up note to the 'DRE'.
2566  if (!IsAssuming) {
2567  PathDiagnosticLocation Loc(DRE, BRC.getSourceManager(), LCtx);
2568  return std::make_shared<PathDiagnosticPopUpPiece>(Loc, Out.str());
2569  }
2570 
2571  PathDiagnosticLocation Loc(Cond, BRC.getSourceManager(), LCtx);
2572  auto event = std::make_shared<PathDiagnosticEventPiece>(Loc, Out.str());
2573 
2574  if (isInterestingExpr(DRE, N, &report))
2575  event->setPrunable(false);
2576 
2577  return std::move(event);
2578 }
2579 
2580 PathDiagnosticPieceRef ConditionBRVisitor::VisitTrueTest(
2581  const Expr *Cond, const MemberExpr *ME, BugReporterContext &BRC,
2582  PathSensitiveBugReport &report, const ExplodedNode *N, bool TookTrue,
2583  bool IsAssuming) {
2584  SmallString<256> Buf;
2585  llvm::raw_svector_ostream Out(Buf);
2586 
2587  Out << (IsAssuming ? "Assuming field '" : "Field '")
2588  << ME->getMemberDecl()->getName() << "' is ";
2589 
2590  if (!printValue(ME, Out, N, TookTrue, IsAssuming))
2591  return nullptr;
2592 
2593  const LocationContext *LCtx = N->getLocationContext();
2594  PathDiagnosticLocation Loc;
2595 
2596  // If we know the value create a pop-up note to the member of the MemberExpr.
2597  if (!IsAssuming && ME->getMemberLoc().isValid())
2598  Loc = PathDiagnosticLocation(ME->getMemberLoc(), BRC.getSourceManager());
2599  else
2600  Loc = PathDiagnosticLocation(Cond, BRC.getSourceManager(), LCtx);
2601 
2602  if (!Loc.isValid() || !Loc.asLocation().isValid())
2603  return nullptr;
2604 
2605  if (isVarAnInterestingCondition(ME, N, &report))
2606  Out << WillBeUsedForACondition;
2607 
2608  // If we know the value create a pop-up note.
2609  if (!IsAssuming)
2610  return std::make_shared<PathDiagnosticPopUpPiece>(Loc, Out.str());
2611 
2612  auto event = std::make_shared<PathDiagnosticEventPiece>(Loc, Out.str());
2613  if (isInterestingExpr(ME, N, &report))
2614  event->setPrunable(false);
2615  return event;
2616 }
2617 
2618 bool ConditionBRVisitor::printValue(const Expr *CondVarExpr, raw_ostream &Out,
2619  const ExplodedNode *N, bool TookTrue,
2620  bool IsAssuming) {
2621  QualType Ty = CondVarExpr->getType();
2622 
2623  if (Ty->isPointerType()) {
2624  Out << (TookTrue ? "non-null" : "null");
2625  return true;
2626  }
2627 
2628  if (Ty->isObjCObjectPointerType()) {
2629  Out << (TookTrue ? "non-nil" : "nil");
2630  return true;
2631  }
2632 
2633  if (!Ty->isIntegralOrEnumerationType())
2634  return false;
2635 
2637  if (!IsAssuming)
2638  IntValue = getConcreteIntegerValue(CondVarExpr, N);
2639 
2640  if (IsAssuming || !IntValue.hasValue()) {
2641  if (Ty->isBooleanType())
2642  Out << (TookTrue ? "true" : "false");
2643  else
2644  Out << (TookTrue ? "not equal to 0" : "0");
2645  } else {
2646  if (Ty->isBooleanType())
2647  Out << (IntValue.getValue()->getBoolValue() ? "true" : "false");
2648  else
2649  Out << *IntValue.getValue();
2650  }
2651 
2652  return true;
2653 }
2654 
2655 constexpr llvm::StringLiteral ConditionBRVisitor::GenericTrueMessage;
2656 constexpr llvm::StringLiteral ConditionBRVisitor::GenericFalseMessage;
2657 
2658 bool ConditionBRVisitor::isPieceMessageGeneric(
2659  const PathDiagnosticPiece *Piece) {
2660  return Piece->getString() == GenericTrueMessage ||
2661  Piece->getString() == GenericFalseMessage;
2662 }
2663 
2664 //===----------------------------------------------------------------------===//
2665 // Implementation of LikelyFalsePositiveSuppressionBRVisitor.
2666 //===----------------------------------------------------------------------===//
2667 
2668 void LikelyFalsePositiveSuppressionBRVisitor::finalizeVisitor(
2669  BugReporterContext &BRC, const ExplodedNode *N,
2670  PathSensitiveBugReport &BR) {
2671  // Here we suppress false positives coming from system headers. This list is
2672  // based on known issues.
2673  const AnalyzerOptions &Options = BRC.getAnalyzerOptions();
2674  const Decl *D = N->getLocationContext()->getDecl();
2675 
2677  // Skip reports within the 'std' namespace. Although these can sometimes be
2678  // the user's fault, we currently don't report them very well, and
2679  // Note that this will not help for any other data structure libraries, like
2680  // TR1, Boost, or llvm/ADT.
2681  if (Options.ShouldSuppressFromCXXStandardLibrary) {
2682  BR.markInvalid(getTag(), nullptr);
2683  return;
2684  } else {
2685  // If the complete 'std' suppression is not enabled, suppress reports
2686  // from the 'std' namespace that are known to produce false positives.
2687 
2688  // The analyzer issues a false use-after-free when std::list::pop_front
2689  // or std::list::pop_back are called multiple times because we cannot
2690  // reason about the internal invariants of the data structure.
2691  if (const auto *MD = dyn_cast<CXXMethodDecl>(D)) {
2692  const CXXRecordDecl *CD = MD->getParent();
2693  if (CD->getName() == "list") {
2694  BR.markInvalid(getTag(), nullptr);
2695  return;
2696  }
2697  }
2698 
2699  // The analyzer issues a false positive when the constructor of
2700  // std::__independent_bits_engine from algorithms is used.
2701  if (const auto *MD = dyn_cast<CXXConstructorDecl>(D)) {
2702  const CXXRecordDecl *CD = MD->getParent();
2703  if (CD->getName() == "__independent_bits_engine") {
2704  BR.markInvalid(getTag(), nullptr);
2705  return;
2706  }
2707  }
2708 
2709  for (const LocationContext *LCtx = N->getLocationContext(); LCtx;
2710  LCtx = LCtx->getParent()) {
2711  const auto *MD = dyn_cast<CXXMethodDecl>(LCtx->getDecl());
2712  if (!MD)
2713  continue;
2714 
2715  const CXXRecordDecl *CD = MD->getParent();
2716  // The analyzer issues a false positive on
2717  // std::basic_string<uint8_t> v; v.push_back(1);
2718  // and
2719  // std::u16string s; s += u'a';
2720  // because we cannot reason about the internal invariants of the
2721  // data structure.
2722  if (CD->getName() == "basic_string") {
2723  BR.markInvalid(getTag(), nullptr);
2724  return;
2725  }
2726 
2727  // The analyzer issues a false positive on
2728  // std::shared_ptr<int> p(new int(1)); p = nullptr;
2729  // because it does not reason properly about temporary destructors.
2730  if (CD->getName() == "shared_ptr") {
2731  BR.markInvalid(getTag(), nullptr);
2732  return;
2733  }
2734  }
2735  }
2736  }
2737 
2738  // Skip reports within the sys/queue.h macros as we do not have the ability to
2739  // reason about data structure shapes.
2740  const SourceManager &SM = BRC.getSourceManager();
2741  FullSourceLoc Loc = BR.getLocation().asLocation();
2742  while (Loc.isMacroID()) {
2743  Loc = Loc.getSpellingLoc();
2744  if (SM.getFilename(Loc).endswith("sys/queue.h")) {
2745  BR.markInvalid(getTag(), nullptr);
2746  return;
2747  }
2748  }
2749 }
2750 
2751 //===----------------------------------------------------------------------===//
2752 // Implementation of UndefOrNullArgVisitor.
2753 //===----------------------------------------------------------------------===//
2754 
2756 UndefOrNullArgVisitor::VisitNode(const ExplodedNode *N, BugReporterContext &BRC,
2757  PathSensitiveBugReport &BR) {
2758  ProgramStateRef State = N->getState();
2759  ProgramPoint ProgLoc = N->getLocation();
2760 
2761  // We are only interested in visiting CallEnter nodes.
2762  Optional<CallEnter> CEnter = ProgLoc.getAs<CallEnter>();
2763  if (!CEnter)
2764  return nullptr;
2765 
2766  // Check if one of the arguments is the region the visitor is tracking.
2767  CallEventManager &CEMgr = BRC.getStateManager().getCallEventManager();
2768  CallEventRef<> Call = CEMgr.getCaller(CEnter->getCalleeContext(), State);
2769  unsigned Idx = 0;
2770  ArrayRef<ParmVarDecl *> parms = Call->parameters();
2771 
2772  for (const auto ParamDecl : parms) {
2773  const MemRegion *ArgReg = Call->getArgSVal(Idx).getAsRegion();
2774  ++Idx;
2775 
2776  // Are we tracking the argument or its subregion?
2777  if ( !ArgReg || !R->isSubRegionOf(ArgReg->StripCasts()))
2778  continue;
2779 
2780  // Check the function parameter type.
2781  assert(ParamDecl && "Formal parameter has no decl?");
2782  QualType T = ParamDecl->getType();
2783 
2784  if (!(T->isAnyPointerType() || T->isReferenceType())) {
2785  // Function can only change the value passed in by address.
2786  continue;
2787  }
2788 
2789  // If it is a const pointer value, the function does not intend to
2790  // change the value.
2791  if (T->getPointeeType().isConstQualified())
2792  continue;
2793 
2794  // Mark the call site (LocationContext) as interesting if the value of the
2795  // argument is undefined or '0'/'NULL'.
2796  SVal BoundVal = State->getSVal(R);
2797  if (BoundVal.isUndef() || BoundVal.isZeroConstant()) {
2798  BR.markInteresting(CEnter->getCalleeContext());
2799  return nullptr;
2800  }
2801  }
2802  return nullptr;
2803 }
2804 
2805 //===----------------------------------------------------------------------===//
2806 // Implementation of FalsePositiveRefutationBRVisitor.
2807 //===----------------------------------------------------------------------===//
2808 
2809 FalsePositiveRefutationBRVisitor::FalsePositiveRefutationBRVisitor()
2810  : Constraints(ConstraintRangeTy::Factory().getEmptyMap()) {}
2811 
2812 void FalsePositiveRefutationBRVisitor::finalizeVisitor(
2813  BugReporterContext &BRC, const ExplodedNode *EndPathNode,
2814  PathSensitiveBugReport &BR) {
2815  // Collect new constraints
2816  VisitNode(EndPathNode, BRC, BR);
2817 
2818  // Create a refutation manager
2819  llvm::SMTSolverRef RefutationSolver = llvm::CreateZ3Solver();
2820  ASTContext &Ctx = BRC.getASTContext();
2821 
2822  // Add constraints to the solver
2823  for (const auto &I : Constraints) {
2824  const SymbolRef Sym = I.first;
2825  auto RangeIt = I.second.begin();
2826 
2827  llvm::SMTExprRef Constraints = SMTConv::getRangeExpr(
2828  RefutationSolver, Ctx, Sym, RangeIt->From(), RangeIt->To(),
2829  /*InRange=*/true);
2830  while ((++RangeIt) != I.second.end()) {
2831  Constraints = RefutationSolver->mkOr(
2832  Constraints, SMTConv::getRangeExpr(RefutationSolver, Ctx, Sym,
2833  RangeIt->From(), RangeIt->To(),
2834  /*InRange=*/true));
2835  }
2836 
2837  RefutationSolver->addConstraint(Constraints);
2838  }
2839 
2840  // And check for satisfiability
2841  Optional<bool> isSat = RefutationSolver->check();
2842  if (!isSat.hasValue())
2843  return;
2844 
2845  if (!isSat.getValue())
2846  BR.markInvalid("Infeasible constraints", EndPathNode->getLocationContext());
2847 }
2848 
2849 PathDiagnosticPieceRef FalsePositiveRefutationBRVisitor::VisitNode(
2850  const ExplodedNode *N, BugReporterContext &, PathSensitiveBugReport &) {
2851  // Collect new constraints
2852  const ConstraintRangeTy &NewCs = N->getState()->get<ConstraintRange>();
2853  ConstraintRangeTy::Factory &CF =
2854  N->getState()->get_context<ConstraintRange>();
2855 
2856  // Add constraints if we don't have them yet
2857  for (auto const &C : NewCs) {
2858  const SymbolRef &Sym = C.first;
2859  if (!Constraints.contains(Sym)) {
2860  Constraints = CF.add(Constraints, Sym, C.second);
2861  }
2862  }
2863 
2864  return nullptr;
2865 }
2866 
2867 void FalsePositiveRefutationBRVisitor::Profile(
2868  llvm::FoldingSetNodeID &ID) const {
2869  static int Tag = 0;
2870  ID.AddPointer(&Tag);
2871 }
2872 
2873 //===----------------------------------------------------------------------===//
2874 // Implementation of TagVisitor.
2875 //===----------------------------------------------------------------------===//
2876 
2877 int NoteTag::Kind = 0;
2878 
2879 void TagVisitor::Profile(llvm::FoldingSetNodeID &ID) const {
2880  static int Tag = 0;
2881  ID.AddPointer(&Tag);
2882 }
2883 
2884 PathDiagnosticPieceRef TagVisitor::VisitNode(const ExplodedNode *N,
2885  BugReporterContext &BRC,
2886  PathSensitiveBugReport &R) {
2887  ProgramPoint PP = N->getLocation();
2888  const NoteTag *T = dyn_cast_or_null<NoteTag>(PP.getTag());
2889  if (!T)
2890  return nullptr;
2891 
2892  if (Optional<std::string> Msg = T->generateMessage(BRC, R)) {
2893  PathDiagnosticLocation Loc =
2894  PathDiagnosticLocation::create(PP, BRC.getSourceManager());
2895  auto Piece = std::make_shared<PathDiagnosticEventPiece>(Loc, *Msg);
2896  Piece->setPrunable(T->isPrunable());
2897  return Piece;
2898  }
2899 
2900  return nullptr;
2901 }
ObjCPropertyRefExpr - A dot-syntax expression to access an ObjC property.
Definition: ExprObjC.h:614
Indicates that the tracked object is a CF object.
Defines the clang::ASTContext interface.
static ArrayRef< ParmVarDecl * > getCallParameters(CallEventRef<> Call)
Get parameters associated with runtime definition in order to get the correct parameter name...
This is a discriminated union of FileInfo and ExpansionInfo.
A (possibly-)qualified type.
Definition: Type.h:643
static bool isPointerToConst(QualType Ty)
ValueDecl * getMemberDecl() const
Retrieve the member declaration to which this expression refers.
Definition: Expr.h:2894
static StringRef getMacroName(SourceLocation Loc, BugReporterContext &BRC)
const internal::VariadicAllOfMatcher< Stmt > stmt
Matches statements.
succ_iterator succ_begin()
Definition: CFG.h:956
virtual Stmt * getBody() const
getBody - If this Decl represents a declaration for a body of code, such as a function or method defi...
Definition: DeclBase.h:986
static llvm::StringLiteral WillBeUsedForACondition
Stmt - This represents one statement.
Definition: Stmt.h:66
internal::Matcher< Stmt > StatementMatcher
Definition: ASTMatchers.h:138
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:557
internal::PolymorphicMatcherWithParam1< internal::HasDeclarationMatcher, internal::Matcher< Decl >, void(internal::HasDeclarationSupportedTypes)> hasDeclaration(const internal::Matcher< Decl > &InnerMatcher)
Matches a node if the declaration associated with that node matches the given matcher.
Definition: ASTMatchers.h:2971
C Language Family Type Representation.
Defines the SourceManager interface.
static CharSourceRange getTokenRange(SourceRange R)
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
Represents a point when we begin processing an inlined call.
Definition: ProgramPoint.h:630
Manages the lifetime of CallEvent objects.
Definition: CallEvent.h:1148
IntrusiveRefCntPtr< const ProgramState > ProgramStateRef
Opcode getOpcode() const
Definition: Expr.h:3444
StringRef P
const internal::ArgumentAdaptingMatcherFunc< internal::HasDescendantMatcher > hasDescendant
Matches AST nodes that have descendant AST nodes that match the provided matcher. ...
Each ExpansionInfo encodes the expansion location - where the token was ultimately expanded...
llvm::ImmutableMap< SymbolRef, RangeSet > ConstraintRangeTy
unsigned succ_size() const
Definition: CFG.h:974
static bool isAtStartOfMacroExpansion(SourceLocation loc, const SourceManager &SM, const LangOptions &LangOpts, SourceLocation *MacroBegin=nullptr)
Returns true if the given MacroID location points at the first token of the macro expansion...
Definition: Lexer.cpp:800
Represents a variable declaration or definition.
Definition: Decl.h:827
const internal::VariadicDynCastAllOfMatcher< Stmt, BinaryOperator > binaryOperator
Matches binary operator expressions.
const internal::VariadicDynCastAllOfMatcher< Stmt, ObjCIvarRefExpr > objcIvarRefExpr
Matches a reference to an ObjCIvar.
Describes how types, statements, expressions, and declarations should be printed. ...
Definition: PrettyPrinter.h:37
Represents a parameter to a function.
Definition: Decl.h:1600
Defines the clang::Expr interface and subclasses for C++ expressions.
bool isParentOf(const LocationContext *LC) const
Represents a struct/union/class.
Definition: Decl.h:3662
const SymExpr * SymbolRef
Definition: SymExpr.h:110
SourceLocation getBegin() const
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:160
LineState State
field_range fields() const
Definition: Decl.h:3877
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Stmt.cpp:274
Represents a member of a struct/union/class.
Definition: Decl.h:2643
Represents a program point after a store evaluation.
Definition: ProgramPoint.h:431
bool isReferenceType() const
Definition: Type.h:6403
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
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
bool isAssignmentOp() const
Definition: Expr.h:3538
bool isIntegralOrEnumerationType() const
Determine whether this type is an integral or enumeration type.
Definition: Type.h:6754
Represents a point when we start the call exit sequence (for inlined call).
Definition: ProgramPoint.h:668
std::shared_ptr< PathDiagnosticPiece > PathDiagnosticPieceRef
StringRef getOpcodeStr() const
Definition: Expr.h:3465
bool isGLValue() const
Definition: Expr.h:261
BinaryOperatorKind
static bool isInStdNamespace(const Decl *D)
Returns true if the root namespace of the given declaration is the &#39;std&#39; C++ namespace.
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
const LocationContext * getParent() const
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3409
static bool wasRegionOfInterestModifiedAt(const SubRegion *RegionOfInterest, const ExplodedNode *N, SVal ValueAfter)
Expr * IgnoreParenCasts() LLVM_READONLY
Skip past any parentheses and casts which might surround this expression until reaching a fixed point...
Definition: Expr.cpp:2971
static const Expr * peelOffPointerArithmetic(const BinaryOperator *B)
static PathDiagnosticLocation create(const Decl *D, const SourceManager &SM)
Create a location corresponding to the given declaration.
static const MemRegion * getLocationRegionIfReference(const Expr *E, const ExplodedNode *N)
static Optional< const llvm::APSInt * > getConcreteIntegerValue(const Expr *CondVarExpr, const ExplodedNode *N)
SmallVector< BoundNodes, 1 > match(MatcherT Matcher, const NodeT &Node, ASTContext &Context)
Returns the results of matching Matcher on Node.
static bool hasVisibleUpdate(const ExplodedNode *LeftNode, SVal LeftVal, const ExplodedNode *RightNode, SVal RightVal)
Comparing internal representations of symbolic values (via SVal::operator==()) is a valid way to chec...
Expr * IgnoreImpCasts() LLVM_READONLY
Skip past any implicit casts which might surround this expression until reaching a fixed point...
Definition: Expr.cpp:2950
NodeId Parent
Definition: ASTDiff.cpp:191
RecordDecl * getAsRecordDecl() const
Retrieves the RecordDecl this type refers to.
Definition: Type.cpp:1696
static bool isAssertlikeBlock(const CFGBlock *B, ASTContext &Context)
const Stmt * getCallSite() const
Represents a single basic block in a source-level CFG.
Definition: CFG.h:576
static bool potentiallyWritesIntoIvar(const Decl *Parent, const ObjCIvarDecl *Ivar)
Represents a point when we finish the call exit sequence (for inlined call).
Definition: ProgramPoint.h:688
static StringRef getSourceText(CharSourceRange Range, const SourceManager &SM, const LangOptions &LangOpts, bool *Invalid=nullptr)
Returns a string for the source that the range encompasses.
Definition: Lexer.cpp:939
static bool isAtEndOfMacroExpansion(SourceLocation loc, const SourceManager &SM, const LangOptions &LangOpts, SourceLocation *MacroEnd=nullptr)
Returns true if the given MacroID location points at the last token of the macro expansion.
Definition: Lexer.cpp:822
This represents one expression.
Definition: Expr.h:108
Stmt * getTerminatorCondition(bool StripParens=true)
Definition: CFG.cpp:5855
static Optional< SVal > getSValForVar(const Expr *CondVarExpr, const ExplodedNode *N)
Represents a character-granular source range.
CFGBlock * getBlock(Stmt *S)
Returns the CFGBlock the specified Stmt* appears in.
Definition: CFGStmtMap.cpp:26
const Expr * getLastCondition() const
Definition: CFG.cpp:5831
CallEventRef getCaller(const StackFrameContext *CalleeCtx, ProgramStateRef State)
Gets an outside caller given a callee context.
Definition: CallEvent.cpp:1380
#define V(N, I)
Definition: ASTContext.h:2921
bool inTopFrame() const override
Return true if the current LocationContext has no caller context.
Defines the clang::IdentifierInfo, clang::IdentifierTable, and clang::Selector interfaces.
static std::pair< const ProgramPointTag *, const ProgramPointTag * > geteagerlyAssumeBinOpBifurcationTags()
QualType getType() const
Definition: Expr.h:137
CharSourceRange getImmediateExpansionRange(SourceLocation Loc) const
Return the start/end of the expansion information for an expansion location.
DeclContext * getParent()
getParent - Returns the containing DeclContext.
Definition: DeclBase.h:1779
ReturnStmt - This represents a return, optionally of an expression: return; return 4;...
Definition: Stmt.h:2610
An expression that sends a message to the given Objective-C object or class.
Definition: ExprObjC.h:950
SourceLocation getMemberLoc() const
getMemberLoc - Return the location of the "member", in X->F, it is the location of &#39;F&#39;...
Definition: Expr.h:3000
ValueDecl * getDecl()
Definition: Expr.h:1222
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:708
const SourceManager & SM
Definition: Format.cpp:1667
const ExpansionInfo & getExpansion() const
SourceLocation getEndLoc() const LLVM_READONLY
Definition: Stmt.cpp:287
virtual bool hasBody() const
Returns true if this Decl represents a declaration for a body of code, such as a function or method d...
Definition: DeclBase.h:992
bool isConstQualified() const
Determine whether this type is const-qualified.
Definition: Type.h:6207
bool isComparisonOp() const
Definition: Expr.h:3500
Maps string IDs to AST nodes matched by parts of a matcher.
Definition: ASTMatchers.h:103
StringRef getFilename(SourceLocation SpellingLoc) const
Return the filename of the file containing a SourceLocation.
static PathDiagnosticLocation createBegin(const Decl *D, const SourceManager &SM)
Create a location for the beginning of the declaration.
QualType getCanonicalType() const
Definition: Type.h:6187
Encodes a location in the source.
static std::shared_ptr< PathDiagnosticEventPiece > constructDebugPieceForTrackedCondition(const Expr *Cond, const ExplodedNode *N, BugReporterContext &BRC)
static bool isCallStmt(const Stmt *S)
Returns true if this is a statement is a function or method call of some kind.
Definition: CallEvent.cpp:456
static bool Ret(InterpState &S, CodePtr &PC, APValue &Result)
Definition: Interp.cpp:34
ProgramPoints can be "tagged" as representing points specific to a given analysis entity...
Definition: ProgramPoint.h:39
std::string getNameAsString() const
Get a human-readable name for the declaration, even if it is one of the special kinds of names (C++ c...
Definition: Decl.h:291
ASTContext & getASTContext() const LLVM_READONLY
Definition: DeclBase.cpp:377
DeclStmt - Adaptor class for mixing declarations with statements and expressions. ...
Definition: Stmt.h:1203
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:1892
bool isAnyPointerType() const
Definition: Type.h:6395
bool isObjCObjectPointerType() const
Definition: Type.h:6495
static void showBRDiagnostics(const char *action, llvm::raw_svector_ostream &os, const MemRegion *R, SVal V, const DeclStmt *DS)
Show diagnostics for initializing or declaring a region R with a bad value.
static StringRef getImmediateMacroName(SourceLocation Loc, const SourceManager &SM, const LangOptions &LangOpts)
Retrieve the name of the immediate macro expansion.
Definition: Lexer.cpp:975
static bool isFunctionMacroExpansion(SourceLocation Loc, const SourceManager &SM)
Expr * getLHS() const
Definition: Expr.h:3449
ast_type_traits::DynTypedNode Node
bool isInevitablySinking() const
Returns true if the block would eventually end with a sink (a noreturn node).
Definition: CFG.cpp:5793
Dataflow Directional Tag Classes.
static void showBRDefaultDiagnostics(llvm::raw_svector_ostream &os, const MemRegion *R, SVal V)
Show default diagnostics for storing bad region.
bool isValid() const
Return true if this is a valid SourceLocation object.
Parameter for Objective-C &#39;self&#39; argument.
Definition: Decl.h:1545
static bool isVarAnInterestingCondition(const Expr *CondVarExpr, const ExplodedNode *N, const PathSensitiveBugReport *B)
StmtClass getStmtClass() const
Definition: Stmt.h:1087
bool isBooleanType() const
Definition: Type.h:6767
const Decl * getSingleDecl() const
Definition: Stmt.h:1218
const ProgramPointTag * getTag() const
Definition: ProgramPoint.h:177
Stmt * getTerminatorStmt()
Definition: CFG.h:1051
static void showBRParamDiagnostics(llvm::raw_svector_ostream &os, const VarRegion *VR, SVal V)
Display diagnostics for passing bad region as a parameter.
bool isMacroID() const
static bool isInterestingExpr(const Expr *E, const ExplodedNode *N, const PathSensitiveBugReport *B)
static CharSourceRange getAsCharRange(SourceRange Range, const SourceManager &SM, const LangOptions &LangOpts)
Given a token range, produce a corresponding CharSourceRange that is not a token range.
Definition: Lexer.h:394
bool isMacroArgExpansion(SourceLocation Loc, SourceLocation *StartLoc=nullptr) const
Tests whether the given source location represents a macro argument&#39;s expansion into the function-lik...
Indicates that the tracking object is a descendant of a referenced-counted OSObject, used in the Darwin kernel.
const LocationContext * getLocationContext() const
Definition: ProgramPoint.h:179
static bool isAdditiveOp(Opcode Opc)
Definition: Expr.h:3485
const StackFrameContext * getStackFrame() const
Stores options for the analyzer from the command line.
const SrcMgr::SLocEntry & getSLocEntry(FileID FID, bool *Invalid=nullptr) const
ObjCIvarRefExpr - A reference to an ObjC instance variable.
Definition: ExprObjC.h:546
X
Add a minimal nested name specifier fixit hint to allow lookup of a tag name from an outer enclosing ...
Definition: SemaDecl.cpp:14595
Defines the C++ Decl subclasses, other than those for templates (found in DeclTemplate.h) and friends (in DeclFriend.h).
MemberExpr - [C99 6.5.2.3] Structure and Union Members.
Definition: Expr.h:2811
Defines the clang::SourceLocation class and associated facilities.
Represents a C++ struct/union/class.
Definition: DeclCXX.h:255
bool isVoidType() const
Definition: Type.h:6650
ObjCIvarDecl - Represents an ObjC instance variable.
Definition: DeclObjC.h:1944
static bool isInitializationOfVar(const ExplodedNode *N, const VarRegion *VR)
Returns true if N represents the DeclStmt declaring and initializing VR.
SourceRange getSourceRange() const LLVM_READONLY
SourceLocation tokens are not useful in isolation - they are low level value objects created/interpre...
Definition: Stmt.cpp:262
FullSourceLoc getSpellingLoc() const
A SourceLocation and its associated SourceManager.
StringRef getName() const
Get the name of identifier for this declaration as a StringRef.
Definition: Decl.h:275
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1146
Expr * getRHS() const
Definition: Expr.h:3451
bool isFunctionMacroExpansion() const
bool isPointerType() const
Definition: Type.h:6391
QualType getType() const
Definition: Decl.h:655
A trivial tuple used to represent a source range.
Optional< T > getAs() const
Convert to the specified ProgramPoint type, returning None if this ProgramPoint is not of the desired...
Definition: ProgramPoint.h:151
static bool isInterestingLValueExpr(const Expr *Ex)
Returns true if nodes for the given expression kind are always kept around.
This class handles loading and caching of source files into memory.
std::pair< FileID, unsigned > getDecomposedLoc(SourceLocation Loc) const
Decompose the specified location into a raw FileID + Offset pair.
Expr * IgnoreParens() LLVM_READONLY
Skip past any parentheses which might surround this expression until reaching a fixed point...
Definition: Expr.cpp:2962
static llvm::SMTExprRef getRangeExpr(llvm::SMTSolverRef &Solver, ASTContext &Ctx, SymbolRef Sym, const llvm::APSInt &From, const llvm::APSInt &To, bool InRange)
Definition: SMTConv.h:504