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      1 //===--- PathDiagnostic.cpp - Path-Specific Diagnostic Handling -*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file defines the PathDiagnostic-related interfaces.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
     15 #include "clang/AST/Decl.h"
     16 #include "clang/AST/DeclCXX.h"
     17 #include "clang/AST/DeclObjC.h"
     18 #include "clang/AST/Expr.h"
     19 #include "clang/AST/ExprCXX.h"
     20 #include "clang/AST/ParentMap.h"
     21 #include "clang/AST/StmtCXX.h"
     22 #include "clang/Basic/SourceManager.h"
     23 #include "clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h"
     24 #include "llvm/ADT/SmallString.h"
     25 #include "llvm/ADT/StringExtras.h"
     26 #include "llvm/Support/raw_ostream.h"
     27 
     28 using namespace clang;
     29 using namespace ento;
     30 
     31 bool PathDiagnosticMacroPiece::containsEvent() const {
     32   for (PathPieces::const_iterator I = subPieces.begin(), E = subPieces.end();
     33        I!=E; ++I) {
     34     if (isa<PathDiagnosticEventPiece>(*I))
     35       return true;
     36     if (PathDiagnosticMacroPiece *MP = dyn_cast<PathDiagnosticMacroPiece>(*I))
     37       if (MP->containsEvent())
     38         return true;
     39   }
     40   return false;
     41 }
     42 
     43 static StringRef StripTrailingDots(StringRef s) {
     44   for (StringRef::size_type i = s.size(); i != 0; --i)
     45     if (s[i - 1] != '.')
     46       return s.substr(0, i);
     47   return "";
     48 }
     49 
     50 PathDiagnosticPiece::PathDiagnosticPiece(StringRef s,
     51                                          Kind k, DisplayHint hint)
     52   : str(StripTrailingDots(s)), kind(k), Hint(hint),
     53     LastInMainSourceFile(false) {}
     54 
     55 PathDiagnosticPiece::PathDiagnosticPiece(Kind k, DisplayHint hint)
     56   : kind(k), Hint(hint), LastInMainSourceFile(false) {}
     57 
     58 PathDiagnosticPiece::~PathDiagnosticPiece() {}
     59 PathDiagnosticEventPiece::~PathDiagnosticEventPiece() {}
     60 PathDiagnosticCallPiece::~PathDiagnosticCallPiece() {}
     61 PathDiagnosticControlFlowPiece::~PathDiagnosticControlFlowPiece() {}
     62 PathDiagnosticMacroPiece::~PathDiagnosticMacroPiece() {}
     63 
     64 
     65 PathPieces::~PathPieces() {}
     66 
     67 void PathPieces::flattenTo(PathPieces &Primary, PathPieces &Current,
     68                            bool ShouldFlattenMacros) const {
     69   for (PathPieces::const_iterator I = begin(), E = end(); I != E; ++I) {
     70     PathDiagnosticPiece *Piece = I->get();
     71 
     72     switch (Piece->getKind()) {
     73     case PathDiagnosticPiece::Call: {
     74       PathDiagnosticCallPiece *Call = cast<PathDiagnosticCallPiece>(Piece);
     75       IntrusiveRefCntPtr<PathDiagnosticEventPiece> CallEnter =
     76         Call->getCallEnterEvent();
     77       if (CallEnter)
     78         Current.push_back(CallEnter);
     79       Call->path.flattenTo(Primary, Primary, ShouldFlattenMacros);
     80       IntrusiveRefCntPtr<PathDiagnosticEventPiece> callExit =
     81         Call->getCallExitEvent();
     82       if (callExit)
     83         Current.push_back(callExit);
     84       break;
     85     }
     86     case PathDiagnosticPiece::Macro: {
     87       PathDiagnosticMacroPiece *Macro = cast<PathDiagnosticMacroPiece>(Piece);
     88       if (ShouldFlattenMacros) {
     89         Macro->subPieces.flattenTo(Primary, Primary, ShouldFlattenMacros);
     90       } else {
     91         Current.push_back(Piece);
     92         PathPieces NewPath;
     93         Macro->subPieces.flattenTo(Primary, NewPath, ShouldFlattenMacros);
     94         // FIXME: This probably shouldn't mutate the original path piece.
     95         Macro->subPieces = NewPath;
     96       }
     97       break;
     98     }
     99     case PathDiagnosticPiece::Event:
    100     case PathDiagnosticPiece::ControlFlow:
    101       Current.push_back(Piece);
    102       break;
    103     }
    104   }
    105 }
    106 
    107 
    108 PathDiagnostic::~PathDiagnostic() {}
    109 
    110 PathDiagnostic::PathDiagnostic(StringRef CheckName, const Decl *declWithIssue,
    111                                StringRef bugtype, StringRef verboseDesc,
    112                                StringRef shortDesc, StringRef category,
    113                                PathDiagnosticLocation LocationToUnique,
    114                                const Decl *DeclToUnique)
    115   : CheckName(CheckName),
    116     DeclWithIssue(declWithIssue),
    117     BugType(StripTrailingDots(bugtype)),
    118     VerboseDesc(StripTrailingDots(verboseDesc)),
    119     ShortDesc(StripTrailingDots(shortDesc)),
    120     Category(StripTrailingDots(category)),
    121     UniqueingLoc(LocationToUnique),
    122     UniqueingDecl(DeclToUnique),
    123     path(pathImpl) {}
    124 
    125 static PathDiagnosticCallPiece *
    126 getFirstStackedCallToHeaderFile(PathDiagnosticCallPiece *CP,
    127                                 const SourceManager &SMgr) {
    128   SourceLocation CallLoc = CP->callEnter.asLocation();
    129 
    130   // If the call is within a macro, don't do anything (for now).
    131   if (CallLoc.isMacroID())
    132     return nullptr;
    133 
    134   assert(SMgr.isInMainFile(CallLoc) &&
    135          "The call piece should be in the main file.");
    136 
    137   // Check if CP represents a path through a function outside of the main file.
    138   if (!SMgr.isInMainFile(CP->callEnterWithin.asLocation()))
    139     return CP;
    140 
    141   const PathPieces &Path = CP->path;
    142   if (Path.empty())
    143     return nullptr;
    144 
    145   // Check if the last piece in the callee path is a call to a function outside
    146   // of the main file.
    147   if (PathDiagnosticCallPiece *CPInner =
    148       dyn_cast<PathDiagnosticCallPiece>(Path.back())) {
    149     return getFirstStackedCallToHeaderFile(CPInner, SMgr);
    150   }
    151 
    152   // Otherwise, the last piece is in the main file.
    153   return nullptr;
    154 }
    155 
    156 void PathDiagnostic::resetDiagnosticLocationToMainFile() {
    157   if (path.empty())
    158     return;
    159 
    160   PathDiagnosticPiece *LastP = path.back().get();
    161   assert(LastP);
    162   const SourceManager &SMgr = LastP->getLocation().getManager();
    163 
    164   // We only need to check if the report ends inside headers, if the last piece
    165   // is a call piece.
    166   if (PathDiagnosticCallPiece *CP = dyn_cast<PathDiagnosticCallPiece>(LastP)) {
    167     CP = getFirstStackedCallToHeaderFile(CP, SMgr);
    168     if (CP) {
    169       // Mark the piece.
    170        CP->setAsLastInMainSourceFile();
    171 
    172       // Update the path diagnostic message.
    173       const NamedDecl *ND = dyn_cast<NamedDecl>(CP->getCallee());
    174       if (ND) {
    175         SmallString<200> buf;
    176         llvm::raw_svector_ostream os(buf);
    177         os << " (within a call to '" << ND->getDeclName() << "')";
    178         appendToDesc(os.str());
    179       }
    180 
    181       // Reset the report containing declaration and location.
    182       DeclWithIssue = CP->getCaller();
    183       Loc = CP->getLocation();
    184 
    185       return;
    186     }
    187   }
    188 }
    189 
    190 void PathDiagnosticConsumer::anchor() { }
    191 
    192 PathDiagnosticConsumer::~PathDiagnosticConsumer() {
    193   // Delete the contents of the FoldingSet if it isn't empty already.
    194   for (llvm::FoldingSet<PathDiagnostic>::iterator it =
    195        Diags.begin(), et = Diags.end() ; it != et ; ++it) {
    196     delete &*it;
    197   }
    198 }
    199 
    200 void PathDiagnosticConsumer::HandlePathDiagnostic(
    201     std::unique_ptr<PathDiagnostic> D) {
    202   if (!D || D->path.empty())
    203     return;
    204 
    205   // We need to flatten the locations (convert Stmt* to locations) because
    206   // the referenced statements may be freed by the time the diagnostics
    207   // are emitted.
    208   D->flattenLocations();
    209 
    210   // If the PathDiagnosticConsumer does not support diagnostics that
    211   // cross file boundaries, prune out such diagnostics now.
    212   if (!supportsCrossFileDiagnostics()) {
    213     // Verify that the entire path is from the same FileID.
    214     FileID FID;
    215     const SourceManager &SMgr = D->path.front()->getLocation().getManager();
    216     SmallVector<const PathPieces *, 5> WorkList;
    217     WorkList.push_back(&D->path);
    218 
    219     while (!WorkList.empty()) {
    220       const PathPieces &path = *WorkList.pop_back_val();
    221 
    222       for (PathPieces::const_iterator I = path.begin(), E = path.end(); I != E;
    223            ++I) {
    224         const PathDiagnosticPiece *piece = I->get();
    225         FullSourceLoc L = piece->getLocation().asLocation().getExpansionLoc();
    226 
    227         if (FID.isInvalid()) {
    228           FID = SMgr.getFileID(L);
    229         } else if (SMgr.getFileID(L) != FID)
    230           return; // FIXME: Emit a warning?
    231 
    232         // Check the source ranges.
    233         ArrayRef<SourceRange> Ranges = piece->getRanges();
    234         for (ArrayRef<SourceRange>::iterator I = Ranges.begin(),
    235                                              E = Ranges.end(); I != E; ++I) {
    236           SourceLocation L = SMgr.getExpansionLoc(I->getBegin());
    237           if (!L.isFileID() || SMgr.getFileID(L) != FID)
    238             return; // FIXME: Emit a warning?
    239           L = SMgr.getExpansionLoc(I->getEnd());
    240           if (!L.isFileID() || SMgr.getFileID(L) != FID)
    241             return; // FIXME: Emit a warning?
    242         }
    243 
    244         if (const PathDiagnosticCallPiece *call =
    245             dyn_cast<PathDiagnosticCallPiece>(piece)) {
    246           WorkList.push_back(&call->path);
    247         }
    248         else if (const PathDiagnosticMacroPiece *macro =
    249                  dyn_cast<PathDiagnosticMacroPiece>(piece)) {
    250           WorkList.push_back(&macro->subPieces);
    251         }
    252       }
    253     }
    254 
    255     if (FID.isInvalid())
    256       return; // FIXME: Emit a warning?
    257   }
    258 
    259   // Profile the node to see if we already have something matching it
    260   llvm::FoldingSetNodeID profile;
    261   D->Profile(profile);
    262   void *InsertPos = nullptr;
    263 
    264   if (PathDiagnostic *orig = Diags.FindNodeOrInsertPos(profile, InsertPos)) {
    265     // Keep the PathDiagnostic with the shorter path.
    266     // Note, the enclosing routine is called in deterministic order, so the
    267     // results will be consistent between runs (no reason to break ties if the
    268     // size is the same).
    269     const unsigned orig_size = orig->full_size();
    270     const unsigned new_size = D->full_size();
    271     if (orig_size <= new_size)
    272       return;
    273 
    274     assert(orig != D.get());
    275     Diags.RemoveNode(orig);
    276     delete orig;
    277   }
    278 
    279   Diags.InsertNode(D.release());
    280 }
    281 
    282 static Optional<bool> comparePath(const PathPieces &X, const PathPieces &Y);
    283 static Optional<bool>
    284 compareControlFlow(const PathDiagnosticControlFlowPiece &X,
    285                    const PathDiagnosticControlFlowPiece &Y) {
    286   FullSourceLoc XSL = X.getStartLocation().asLocation();
    287   FullSourceLoc YSL = Y.getStartLocation().asLocation();
    288   if (XSL != YSL)
    289     return XSL.isBeforeInTranslationUnitThan(YSL);
    290   FullSourceLoc XEL = X.getEndLocation().asLocation();
    291   FullSourceLoc YEL = Y.getEndLocation().asLocation();
    292   if (XEL != YEL)
    293     return XEL.isBeforeInTranslationUnitThan(YEL);
    294   return None;
    295 }
    296 
    297 static Optional<bool> compareMacro(const PathDiagnosticMacroPiece &X,
    298                                    const PathDiagnosticMacroPiece &Y) {
    299   return comparePath(X.subPieces, Y.subPieces);
    300 }
    301 
    302 static Optional<bool> compareCall(const PathDiagnosticCallPiece &X,
    303                                   const PathDiagnosticCallPiece &Y) {
    304   FullSourceLoc X_CEL = X.callEnter.asLocation();
    305   FullSourceLoc Y_CEL = Y.callEnter.asLocation();
    306   if (X_CEL != Y_CEL)
    307     return X_CEL.isBeforeInTranslationUnitThan(Y_CEL);
    308   FullSourceLoc X_CEWL = X.callEnterWithin.asLocation();
    309   FullSourceLoc Y_CEWL = Y.callEnterWithin.asLocation();
    310   if (X_CEWL != Y_CEWL)
    311     return X_CEWL.isBeforeInTranslationUnitThan(Y_CEWL);
    312   FullSourceLoc X_CRL = X.callReturn.asLocation();
    313   FullSourceLoc Y_CRL = Y.callReturn.asLocation();
    314   if (X_CRL != Y_CRL)
    315     return X_CRL.isBeforeInTranslationUnitThan(Y_CRL);
    316   return comparePath(X.path, Y.path);
    317 }
    318 
    319 static Optional<bool> comparePiece(const PathDiagnosticPiece &X,
    320                                    const PathDiagnosticPiece &Y) {
    321   if (X.getKind() != Y.getKind())
    322     return X.getKind() < Y.getKind();
    323 
    324   FullSourceLoc XL = X.getLocation().asLocation();
    325   FullSourceLoc YL = Y.getLocation().asLocation();
    326   if (XL != YL)
    327     return XL.isBeforeInTranslationUnitThan(YL);
    328 
    329   if (X.getString() != Y.getString())
    330     return X.getString() < Y.getString();
    331 
    332   if (X.getRanges().size() != Y.getRanges().size())
    333     return X.getRanges().size() < Y.getRanges().size();
    334 
    335   const SourceManager &SM = XL.getManager();
    336 
    337   for (unsigned i = 0, n = X.getRanges().size(); i < n; ++i) {
    338     SourceRange XR = X.getRanges()[i];
    339     SourceRange YR = Y.getRanges()[i];
    340     if (XR != YR) {
    341       if (XR.getBegin() != YR.getBegin())
    342         return SM.isBeforeInTranslationUnit(XR.getBegin(), YR.getBegin());
    343       return SM.isBeforeInTranslationUnit(XR.getEnd(), YR.getEnd());
    344     }
    345   }
    346 
    347   switch (X.getKind()) {
    348     case clang::ento::PathDiagnosticPiece::ControlFlow:
    349       return compareControlFlow(cast<PathDiagnosticControlFlowPiece>(X),
    350                                 cast<PathDiagnosticControlFlowPiece>(Y));
    351     case clang::ento::PathDiagnosticPiece::Event:
    352       return None;
    353     case clang::ento::PathDiagnosticPiece::Macro:
    354       return compareMacro(cast<PathDiagnosticMacroPiece>(X),
    355                           cast<PathDiagnosticMacroPiece>(Y));
    356     case clang::ento::PathDiagnosticPiece::Call:
    357       return compareCall(cast<PathDiagnosticCallPiece>(X),
    358                          cast<PathDiagnosticCallPiece>(Y));
    359   }
    360   llvm_unreachable("all cases handled");
    361 }
    362 
    363 static Optional<bool> comparePath(const PathPieces &X, const PathPieces &Y) {
    364   if (X.size() != Y.size())
    365     return X.size() < Y.size();
    366 
    367   PathPieces::const_iterator X_I = X.begin(), X_end = X.end();
    368   PathPieces::const_iterator Y_I = Y.begin(), Y_end = Y.end();
    369 
    370   for ( ; X_I != X_end && Y_I != Y_end; ++X_I, ++Y_I) {
    371     Optional<bool> b = comparePiece(**X_I, **Y_I);
    372     if (b.hasValue())
    373       return b.getValue();
    374   }
    375 
    376   return None;
    377 }
    378 
    379 static bool compare(const PathDiagnostic &X, const PathDiagnostic &Y) {
    380   FullSourceLoc XL = X.getLocation().asLocation();
    381   FullSourceLoc YL = Y.getLocation().asLocation();
    382   if (XL != YL)
    383     return XL.isBeforeInTranslationUnitThan(YL);
    384   if (X.getBugType() != Y.getBugType())
    385     return X.getBugType() < Y.getBugType();
    386   if (X.getCategory() != Y.getCategory())
    387     return X.getCategory() < Y.getCategory();
    388   if (X.getVerboseDescription() != Y.getVerboseDescription())
    389     return X.getVerboseDescription() < Y.getVerboseDescription();
    390   if (X.getShortDescription() != Y.getShortDescription())
    391     return X.getShortDescription() < Y.getShortDescription();
    392   if (X.getDeclWithIssue() != Y.getDeclWithIssue()) {
    393     const Decl *XD = X.getDeclWithIssue();
    394     if (!XD)
    395       return true;
    396     const Decl *YD = Y.getDeclWithIssue();
    397     if (!YD)
    398       return false;
    399     SourceLocation XDL = XD->getLocation();
    400     SourceLocation YDL = YD->getLocation();
    401     if (XDL != YDL) {
    402       const SourceManager &SM = XL.getManager();
    403       return SM.isBeforeInTranslationUnit(XDL, YDL);
    404     }
    405   }
    406   PathDiagnostic::meta_iterator XI = X.meta_begin(), XE = X.meta_end();
    407   PathDiagnostic::meta_iterator YI = Y.meta_begin(), YE = Y.meta_end();
    408   if (XE - XI != YE - YI)
    409     return (XE - XI) < (YE - YI);
    410   for ( ; XI != XE ; ++XI, ++YI) {
    411     if (*XI != *YI)
    412       return (*XI) < (*YI);
    413   }
    414   Optional<bool> b = comparePath(X.path, Y.path);
    415   assert(b.hasValue());
    416   return b.getValue();
    417 }
    418 
    419 void PathDiagnosticConsumer::FlushDiagnostics(
    420                                      PathDiagnosticConsumer::FilesMade *Files) {
    421   if (flushed)
    422     return;
    423 
    424   flushed = true;
    425 
    426   std::vector<const PathDiagnostic *> BatchDiags;
    427   for (llvm::FoldingSet<PathDiagnostic>::iterator it = Diags.begin(),
    428        et = Diags.end(); it != et; ++it) {
    429     const PathDiagnostic *D = &*it;
    430     BatchDiags.push_back(D);
    431   }
    432 
    433   // Sort the diagnostics so that they are always emitted in a deterministic
    434   // order.
    435   int (*Comp)(const PathDiagnostic *const *, const PathDiagnostic *const *) =
    436       [](const PathDiagnostic *const *X, const PathDiagnostic *const *Y) {
    437         assert(*X != *Y && "PathDiagnostics not uniqued!");
    438         if (compare(**X, **Y))
    439           return -1;
    440         assert(compare(**Y, **X) && "Not a total order!");
    441         return 1;
    442       };
    443   array_pod_sort(BatchDiags.begin(), BatchDiags.end(), Comp);
    444 
    445   FlushDiagnosticsImpl(BatchDiags, Files);
    446 
    447   // Delete the flushed diagnostics.
    448   for (std::vector<const PathDiagnostic *>::iterator it = BatchDiags.begin(),
    449        et = BatchDiags.end(); it != et; ++it) {
    450     const PathDiagnostic *D = *it;
    451     delete D;
    452   }
    453 
    454   // Clear out the FoldingSet.
    455   Diags.clear();
    456 }
    457 
    458 PathDiagnosticConsumer::FilesMade::~FilesMade() {
    459   for (PDFileEntry &Entry : Set)
    460     Entry.~PDFileEntry();
    461 }
    462 
    463 void PathDiagnosticConsumer::FilesMade::addDiagnostic(const PathDiagnostic &PD,
    464                                                       StringRef ConsumerName,
    465                                                       StringRef FileName) {
    466   llvm::FoldingSetNodeID NodeID;
    467   NodeID.Add(PD);
    468   void *InsertPos;
    469   PDFileEntry *Entry = Set.FindNodeOrInsertPos(NodeID, InsertPos);
    470   if (!Entry) {
    471     Entry = Alloc.Allocate<PDFileEntry>();
    472     Entry = new (Entry) PDFileEntry(NodeID);
    473     Set.InsertNode(Entry, InsertPos);
    474   }
    475 
    476   // Allocate persistent storage for the file name.
    477   char *FileName_cstr = (char*) Alloc.Allocate(FileName.size(), 1);
    478   memcpy(FileName_cstr, FileName.data(), FileName.size());
    479 
    480   Entry->files.push_back(std::make_pair(ConsumerName,
    481                                         StringRef(FileName_cstr,
    482                                                   FileName.size())));
    483 }
    484 
    485 PathDiagnosticConsumer::PDFileEntry::ConsumerFiles *
    486 PathDiagnosticConsumer::FilesMade::getFiles(const PathDiagnostic &PD) {
    487   llvm::FoldingSetNodeID NodeID;
    488   NodeID.Add(PD);
    489   void *InsertPos;
    490   PDFileEntry *Entry = Set.FindNodeOrInsertPos(NodeID, InsertPos);
    491   if (!Entry)
    492     return nullptr;
    493   return &Entry->files;
    494 }
    495 
    496 //===----------------------------------------------------------------------===//
    497 // PathDiagnosticLocation methods.
    498 //===----------------------------------------------------------------------===//
    499 
    500 static SourceLocation getValidSourceLocation(const Stmt* S,
    501                                              LocationOrAnalysisDeclContext LAC,
    502                                              bool UseEnd = false) {
    503   SourceLocation L = UseEnd ? S->getLocEnd() : S->getLocStart();
    504   assert(!LAC.isNull() && "A valid LocationContext or AnalysisDeclContext should "
    505                           "be passed to PathDiagnosticLocation upon creation.");
    506 
    507   // S might be a temporary statement that does not have a location in the
    508   // source code, so find an enclosing statement and use its location.
    509   if (!L.isValid()) {
    510 
    511     AnalysisDeclContext *ADC;
    512     if (LAC.is<const LocationContext*>())
    513       ADC = LAC.get<const LocationContext*>()->getAnalysisDeclContext();
    514     else
    515       ADC = LAC.get<AnalysisDeclContext*>();
    516 
    517     ParentMap &PM = ADC->getParentMap();
    518 
    519     const Stmt *Parent = S;
    520     do {
    521       Parent = PM.getParent(Parent);
    522 
    523       // In rare cases, we have implicit top-level expressions,
    524       // such as arguments for implicit member initializers.
    525       // In this case, fall back to the start of the body (even if we were
    526       // asked for the statement end location).
    527       if (!Parent) {
    528         const Stmt *Body = ADC->getBody();
    529         if (Body)
    530           L = Body->getLocStart();
    531         else
    532           L = ADC->getDecl()->getLocEnd();
    533         break;
    534       }
    535 
    536       L = UseEnd ? Parent->getLocEnd() : Parent->getLocStart();
    537     } while (!L.isValid());
    538   }
    539 
    540   return L;
    541 }
    542 
    543 static PathDiagnosticLocation
    544 getLocationForCaller(const StackFrameContext *SFC,
    545                      const LocationContext *CallerCtx,
    546                      const SourceManager &SM) {
    547   const CFGBlock &Block = *SFC->getCallSiteBlock();
    548   CFGElement Source = Block[SFC->getIndex()];
    549 
    550   switch (Source.getKind()) {
    551   case CFGElement::Statement:
    552     return PathDiagnosticLocation(Source.castAs<CFGStmt>().getStmt(),
    553                                   SM, CallerCtx);
    554   case CFGElement::Initializer: {
    555     const CFGInitializer &Init = Source.castAs<CFGInitializer>();
    556     return PathDiagnosticLocation(Init.getInitializer()->getInit(),
    557                                   SM, CallerCtx);
    558   }
    559   case CFGElement::AutomaticObjectDtor: {
    560     const CFGAutomaticObjDtor &Dtor = Source.castAs<CFGAutomaticObjDtor>();
    561     return PathDiagnosticLocation::createEnd(Dtor.getTriggerStmt(),
    562                                              SM, CallerCtx);
    563   }
    564   case CFGElement::DeleteDtor: {
    565     const CFGDeleteDtor &Dtor = Source.castAs<CFGDeleteDtor>();
    566     return PathDiagnosticLocation(Dtor.getDeleteExpr(), SM, CallerCtx);
    567   }
    568   case CFGElement::BaseDtor:
    569   case CFGElement::MemberDtor: {
    570     const AnalysisDeclContext *CallerInfo = CallerCtx->getAnalysisDeclContext();
    571     if (const Stmt *CallerBody = CallerInfo->getBody())
    572       return PathDiagnosticLocation::createEnd(CallerBody, SM, CallerCtx);
    573     return PathDiagnosticLocation::create(CallerInfo->getDecl(), SM);
    574   }
    575   case CFGElement::TemporaryDtor:
    576   case CFGElement::NewAllocator:
    577     llvm_unreachable("not yet implemented!");
    578   }
    579 
    580   llvm_unreachable("Unknown CFGElement kind");
    581 }
    582 
    583 
    584 PathDiagnosticLocation
    585   PathDiagnosticLocation::createBegin(const Decl *D,
    586                                       const SourceManager &SM) {
    587   return PathDiagnosticLocation(D->getLocStart(), SM, SingleLocK);
    588 }
    589 
    590 PathDiagnosticLocation
    591   PathDiagnosticLocation::createBegin(const Stmt *S,
    592                                       const SourceManager &SM,
    593                                       LocationOrAnalysisDeclContext LAC) {
    594   return PathDiagnosticLocation(getValidSourceLocation(S, LAC),
    595                                 SM, SingleLocK);
    596 }
    597 
    598 
    599 PathDiagnosticLocation
    600 PathDiagnosticLocation::createEnd(const Stmt *S,
    601                                   const SourceManager &SM,
    602                                   LocationOrAnalysisDeclContext LAC) {
    603   if (const CompoundStmt *CS = dyn_cast<CompoundStmt>(S))
    604     return createEndBrace(CS, SM);
    605   return PathDiagnosticLocation(getValidSourceLocation(S, LAC, /*End=*/true),
    606                                 SM, SingleLocK);
    607 }
    608 
    609 PathDiagnosticLocation
    610   PathDiagnosticLocation::createOperatorLoc(const BinaryOperator *BO,
    611                                             const SourceManager &SM) {
    612   return PathDiagnosticLocation(BO->getOperatorLoc(), SM, SingleLocK);
    613 }
    614 
    615 PathDiagnosticLocation
    616   PathDiagnosticLocation::createConditionalColonLoc(
    617                                             const ConditionalOperator *CO,
    618                                             const SourceManager &SM) {
    619   return PathDiagnosticLocation(CO->getColonLoc(), SM, SingleLocK);
    620 }
    621 
    622 
    623 PathDiagnosticLocation
    624   PathDiagnosticLocation::createMemberLoc(const MemberExpr *ME,
    625                                           const SourceManager &SM) {
    626   return PathDiagnosticLocation(ME->getMemberLoc(), SM, SingleLocK);
    627 }
    628 
    629 PathDiagnosticLocation
    630   PathDiagnosticLocation::createBeginBrace(const CompoundStmt *CS,
    631                                            const SourceManager &SM) {
    632   SourceLocation L = CS->getLBracLoc();
    633   return PathDiagnosticLocation(L, SM, SingleLocK);
    634 }
    635 
    636 PathDiagnosticLocation
    637   PathDiagnosticLocation::createEndBrace(const CompoundStmt *CS,
    638                                          const SourceManager &SM) {
    639   SourceLocation L = CS->getRBracLoc();
    640   return PathDiagnosticLocation(L, SM, SingleLocK);
    641 }
    642 
    643 PathDiagnosticLocation
    644   PathDiagnosticLocation::createDeclBegin(const LocationContext *LC,
    645                                           const SourceManager &SM) {
    646   // FIXME: Should handle CXXTryStmt if analyser starts supporting C++.
    647   if (const CompoundStmt *CS =
    648         dyn_cast_or_null<CompoundStmt>(LC->getDecl()->getBody()))
    649     if (!CS->body_empty()) {
    650       SourceLocation Loc = (*CS->body_begin())->getLocStart();
    651       return PathDiagnosticLocation(Loc, SM, SingleLocK);
    652     }
    653 
    654   return PathDiagnosticLocation();
    655 }
    656 
    657 PathDiagnosticLocation
    658   PathDiagnosticLocation::createDeclEnd(const LocationContext *LC,
    659                                         const SourceManager &SM) {
    660   SourceLocation L = LC->getDecl()->getBodyRBrace();
    661   return PathDiagnosticLocation(L, SM, SingleLocK);
    662 }
    663 
    664 PathDiagnosticLocation
    665   PathDiagnosticLocation::create(const ProgramPoint& P,
    666                                  const SourceManager &SMng) {
    667 
    668   const Stmt* S = nullptr;
    669   if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
    670     const CFGBlock *BSrc = BE->getSrc();
    671     S = BSrc->getTerminatorCondition();
    672   } else if (Optional<StmtPoint> SP = P.getAs<StmtPoint>()) {
    673     S = SP->getStmt();
    674     if (P.getAs<PostStmtPurgeDeadSymbols>())
    675       return PathDiagnosticLocation::createEnd(S, SMng, P.getLocationContext());
    676   } else if (Optional<PostInitializer> PIP = P.getAs<PostInitializer>()) {
    677     return PathDiagnosticLocation(PIP->getInitializer()->getSourceLocation(),
    678                                   SMng);
    679   } else if (Optional<PostImplicitCall> PIE = P.getAs<PostImplicitCall>()) {
    680     return PathDiagnosticLocation(PIE->getLocation(), SMng);
    681   } else if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
    682     return getLocationForCaller(CE->getCalleeContext(),
    683                                 CE->getLocationContext(),
    684                                 SMng);
    685   } else if (Optional<CallExitEnd> CEE = P.getAs<CallExitEnd>()) {
    686     return getLocationForCaller(CEE->getCalleeContext(),
    687                                 CEE->getLocationContext(),
    688                                 SMng);
    689   } else {
    690     llvm_unreachable("Unexpected ProgramPoint");
    691   }
    692 
    693   return PathDiagnosticLocation(S, SMng, P.getLocationContext());
    694 }
    695 
    696 const Stmt *PathDiagnosticLocation::getStmt(const ExplodedNode *N) {
    697   ProgramPoint P = N->getLocation();
    698   if (Optional<StmtPoint> SP = P.getAs<StmtPoint>())
    699     return SP->getStmt();
    700   if (Optional<BlockEdge> BE = P.getAs<BlockEdge>())
    701     return BE->getSrc()->getTerminator();
    702   if (Optional<CallEnter> CE = P.getAs<CallEnter>())
    703     return CE->getCallExpr();
    704   if (Optional<CallExitEnd> CEE = P.getAs<CallExitEnd>())
    705     return CEE->getCalleeContext()->getCallSite();
    706   if (Optional<PostInitializer> PIPP = P.getAs<PostInitializer>())
    707     return PIPP->getInitializer()->getInit();
    708 
    709   return nullptr;
    710 }
    711 
    712 const Stmt *PathDiagnosticLocation::getNextStmt(const ExplodedNode *N) {
    713   for (N = N->getFirstSucc(); N; N = N->getFirstSucc()) {
    714     if (const Stmt *S = getStmt(N)) {
    715       // Check if the statement is '?' or '&&'/'||'.  These are "merges",
    716       // not actual statement points.
    717       switch (S->getStmtClass()) {
    718         case Stmt::ChooseExprClass:
    719         case Stmt::BinaryConditionalOperatorClass:
    720         case Stmt::ConditionalOperatorClass:
    721           continue;
    722         case Stmt::BinaryOperatorClass: {
    723           BinaryOperatorKind Op = cast<BinaryOperator>(S)->getOpcode();
    724           if (Op == BO_LAnd || Op == BO_LOr)
    725             continue;
    726           break;
    727         }
    728         default:
    729           break;
    730       }
    731       // We found the statement, so return it.
    732       return S;
    733     }
    734   }
    735 
    736   return nullptr;
    737 }
    738 
    739 PathDiagnosticLocation
    740   PathDiagnosticLocation::createEndOfPath(const ExplodedNode *N,
    741                                           const SourceManager &SM) {
    742   assert(N && "Cannot create a location with a null node.");
    743   const Stmt *S = getStmt(N);
    744 
    745   if (!S) {
    746     // If this is an implicit call, return the implicit call point location.
    747     if (Optional<PreImplicitCall> PIE = N->getLocationAs<PreImplicitCall>())
    748       return PathDiagnosticLocation(PIE->getLocation(), SM);
    749     S = getNextStmt(N);
    750   }
    751 
    752   if (S) {
    753     ProgramPoint P = N->getLocation();
    754     const LocationContext *LC = N->getLocationContext();
    755 
    756     // For member expressions, return the location of the '.' or '->'.
    757     if (const MemberExpr *ME = dyn_cast<MemberExpr>(S))
    758       return PathDiagnosticLocation::createMemberLoc(ME, SM);
    759 
    760     // For binary operators, return the location of the operator.
    761     if (const BinaryOperator *B = dyn_cast<BinaryOperator>(S))
    762       return PathDiagnosticLocation::createOperatorLoc(B, SM);
    763 
    764     if (P.getAs<PostStmtPurgeDeadSymbols>())
    765       return PathDiagnosticLocation::createEnd(S, SM, LC);
    766 
    767     if (S->getLocStart().isValid())
    768       return PathDiagnosticLocation(S, SM, LC);
    769     return PathDiagnosticLocation(getValidSourceLocation(S, LC), SM);
    770   }
    771 
    772   return createDeclEnd(N->getLocationContext(), SM);
    773 }
    774 
    775 PathDiagnosticLocation PathDiagnosticLocation::createSingleLocation(
    776                                            const PathDiagnosticLocation &PDL) {
    777   FullSourceLoc L = PDL.asLocation();
    778   return PathDiagnosticLocation(L, L.getManager(), SingleLocK);
    779 }
    780 
    781 FullSourceLoc
    782   PathDiagnosticLocation::genLocation(SourceLocation L,
    783                                       LocationOrAnalysisDeclContext LAC) const {
    784   assert(isValid());
    785   // Note that we want a 'switch' here so that the compiler can warn us in
    786   // case we add more cases.
    787   switch (K) {
    788     case SingleLocK:
    789     case RangeK:
    790       break;
    791     case StmtK:
    792       // Defensive checking.
    793       if (!S)
    794         break;
    795       return FullSourceLoc(getValidSourceLocation(S, LAC),
    796                            const_cast<SourceManager&>(*SM));
    797     case DeclK:
    798       // Defensive checking.
    799       if (!D)
    800         break;
    801       return FullSourceLoc(D->getLocation(), const_cast<SourceManager&>(*SM));
    802   }
    803 
    804   return FullSourceLoc(L, const_cast<SourceManager&>(*SM));
    805 }
    806 
    807 PathDiagnosticRange
    808   PathDiagnosticLocation::genRange(LocationOrAnalysisDeclContext LAC) const {
    809   assert(isValid());
    810   // Note that we want a 'switch' here so that the compiler can warn us in
    811   // case we add more cases.
    812   switch (K) {
    813     case SingleLocK:
    814       return PathDiagnosticRange(SourceRange(Loc,Loc), true);
    815     case RangeK:
    816       break;
    817     case StmtK: {
    818       const Stmt *S = asStmt();
    819       switch (S->getStmtClass()) {
    820         default:
    821           break;
    822         case Stmt::DeclStmtClass: {
    823           const DeclStmt *DS = cast<DeclStmt>(S);
    824           if (DS->isSingleDecl()) {
    825             // Should always be the case, but we'll be defensive.
    826             return SourceRange(DS->getLocStart(),
    827                                DS->getSingleDecl()->getLocation());
    828           }
    829           break;
    830         }
    831           // FIXME: Provide better range information for different
    832           //  terminators.
    833         case Stmt::IfStmtClass:
    834         case Stmt::WhileStmtClass:
    835         case Stmt::DoStmtClass:
    836         case Stmt::ForStmtClass:
    837         case Stmt::ChooseExprClass:
    838         case Stmt::IndirectGotoStmtClass:
    839         case Stmt::SwitchStmtClass:
    840         case Stmt::BinaryConditionalOperatorClass:
    841         case Stmt::ConditionalOperatorClass:
    842         case Stmt::ObjCForCollectionStmtClass: {
    843           SourceLocation L = getValidSourceLocation(S, LAC);
    844           return SourceRange(L, L);
    845         }
    846       }
    847       SourceRange R = S->getSourceRange();
    848       if (R.isValid())
    849         return R;
    850       break;
    851     }
    852     case DeclK:
    853       if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
    854         return MD->getSourceRange();
    855       if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
    856         if (Stmt *Body = FD->getBody())
    857           return Body->getSourceRange();
    858       }
    859       else {
    860         SourceLocation L = D->getLocation();
    861         return PathDiagnosticRange(SourceRange(L, L), true);
    862       }
    863   }
    864 
    865   return SourceRange(Loc,Loc);
    866 }
    867 
    868 void PathDiagnosticLocation::flatten() {
    869   if (K == StmtK) {
    870     K = RangeK;
    871     S = nullptr;
    872     D = nullptr;
    873   }
    874   else if (K == DeclK) {
    875     K = SingleLocK;
    876     S = nullptr;
    877     D = nullptr;
    878   }
    879 }
    880 
    881 //===----------------------------------------------------------------------===//
    882 // Manipulation of PathDiagnosticCallPieces.
    883 //===----------------------------------------------------------------------===//
    884 
    885 PathDiagnosticCallPiece *
    886 PathDiagnosticCallPiece::construct(const ExplodedNode *N,
    887                                    const CallExitEnd &CE,
    888                                    const SourceManager &SM) {
    889   const Decl *caller = CE.getLocationContext()->getDecl();
    890   PathDiagnosticLocation pos = getLocationForCaller(CE.getCalleeContext(),
    891                                                     CE.getLocationContext(),
    892                                                     SM);
    893   return new PathDiagnosticCallPiece(caller, pos);
    894 }
    895 
    896 PathDiagnosticCallPiece *
    897 PathDiagnosticCallPiece::construct(PathPieces &path,
    898                                    const Decl *caller) {
    899   PathDiagnosticCallPiece *C = new PathDiagnosticCallPiece(path, caller);
    900   path.clear();
    901   path.push_front(C);
    902   return C;
    903 }
    904 
    905 void PathDiagnosticCallPiece::setCallee(const CallEnter &CE,
    906                                         const SourceManager &SM) {
    907   const StackFrameContext *CalleeCtx = CE.getCalleeContext();
    908   Callee = CalleeCtx->getDecl();
    909 
    910   callEnterWithin = PathDiagnosticLocation::createBegin(Callee, SM);
    911   callEnter = getLocationForCaller(CalleeCtx, CE.getLocationContext(), SM);
    912 }
    913 
    914 static inline void describeClass(raw_ostream &Out, const CXXRecordDecl *D,
    915                                  StringRef Prefix = StringRef()) {
    916   if (!D->getIdentifier())
    917     return;
    918   Out << Prefix << '\'' << *D << '\'';
    919 }
    920 
    921 static bool describeCodeDecl(raw_ostream &Out, const Decl *D,
    922                              bool ExtendedDescription,
    923                              StringRef Prefix = StringRef()) {
    924   if (!D)
    925     return false;
    926 
    927   if (isa<BlockDecl>(D)) {
    928     if (ExtendedDescription)
    929       Out << Prefix << "anonymous block";
    930     return ExtendedDescription;
    931   }
    932 
    933   if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
    934     Out << Prefix;
    935     if (ExtendedDescription && !MD->isUserProvided()) {
    936       if (MD->isExplicitlyDefaulted())
    937         Out << "defaulted ";
    938       else
    939         Out << "implicit ";
    940     }
    941 
    942     if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(MD)) {
    943       if (CD->isDefaultConstructor())
    944         Out << "default ";
    945       else if (CD->isCopyConstructor())
    946         Out << "copy ";
    947       else if (CD->isMoveConstructor())
    948         Out << "move ";
    949 
    950       Out << "constructor";
    951       describeClass(Out, MD->getParent(), " for ");
    952 
    953     } else if (isa<CXXDestructorDecl>(MD)) {
    954       if (!MD->isUserProvided()) {
    955         Out << "destructor";
    956         describeClass(Out, MD->getParent(), " for ");
    957       } else {
    958         // Use ~Foo for explicitly-written destructors.
    959         Out << "'" << *MD << "'";
    960       }
    961 
    962     } else if (MD->isCopyAssignmentOperator()) {
    963         Out << "copy assignment operator";
    964         describeClass(Out, MD->getParent(), " for ");
    965 
    966     } else if (MD->isMoveAssignmentOperator()) {
    967         Out << "move assignment operator";
    968         describeClass(Out, MD->getParent(), " for ");
    969 
    970     } else {
    971       if (MD->getParent()->getIdentifier())
    972         Out << "'" << *MD->getParent() << "::" << *MD << "'";
    973       else
    974         Out << "'" << *MD << "'";
    975     }
    976 
    977     return true;
    978   }
    979 
    980   Out << Prefix << '\'' << cast<NamedDecl>(*D) << '\'';
    981   return true;
    982 }
    983 
    984 IntrusiveRefCntPtr<PathDiagnosticEventPiece>
    985 PathDiagnosticCallPiece::getCallEnterEvent() const {
    986   if (!Callee)
    987     return nullptr;
    988 
    989   SmallString<256> buf;
    990   llvm::raw_svector_ostream Out(buf);
    991 
    992   Out << "Calling ";
    993   describeCodeDecl(Out, Callee, /*ExtendedDescription=*/true);
    994 
    995   assert(callEnter.asLocation().isValid());
    996   return new PathDiagnosticEventPiece(callEnter, Out.str());
    997 }
    998 
    999 IntrusiveRefCntPtr<PathDiagnosticEventPiece>
   1000 PathDiagnosticCallPiece::getCallEnterWithinCallerEvent() const {
   1001   if (!callEnterWithin.asLocation().isValid())
   1002     return nullptr;
   1003   if (Callee->isImplicit() || !Callee->hasBody())
   1004     return nullptr;
   1005   if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Callee))
   1006     if (MD->isDefaulted())
   1007       return nullptr;
   1008 
   1009   SmallString<256> buf;
   1010   llvm::raw_svector_ostream Out(buf);
   1011 
   1012   Out << "Entered call";
   1013   describeCodeDecl(Out, Caller, /*ExtendedDescription=*/false, " from ");
   1014 
   1015   return new PathDiagnosticEventPiece(callEnterWithin, Out.str());
   1016 }
   1017 
   1018 IntrusiveRefCntPtr<PathDiagnosticEventPiece>
   1019 PathDiagnosticCallPiece::getCallExitEvent() const {
   1020   if (NoExit)
   1021     return nullptr;
   1022 
   1023   SmallString<256> buf;
   1024   llvm::raw_svector_ostream Out(buf);
   1025 
   1026   if (!CallStackMessage.empty()) {
   1027     Out << CallStackMessage;
   1028   } else {
   1029     bool DidDescribe = describeCodeDecl(Out, Callee,
   1030                                         /*ExtendedDescription=*/false,
   1031                                         "Returning from ");
   1032     if (!DidDescribe)
   1033       Out << "Returning to caller";
   1034   }
   1035 
   1036   assert(callReturn.asLocation().isValid());
   1037   return new PathDiagnosticEventPiece(callReturn, Out.str());
   1038 }
   1039 
   1040 static void compute_path_size(const PathPieces &pieces, unsigned &size) {
   1041   for (PathPieces::const_iterator it = pieces.begin(),
   1042                                   et = pieces.end(); it != et; ++it) {
   1043     const PathDiagnosticPiece *piece = it->get();
   1044     if (const PathDiagnosticCallPiece *cp =
   1045         dyn_cast<PathDiagnosticCallPiece>(piece)) {
   1046       compute_path_size(cp->path, size);
   1047     }
   1048     else
   1049       ++size;
   1050   }
   1051 }
   1052 
   1053 unsigned PathDiagnostic::full_size() {
   1054   unsigned size = 0;
   1055   compute_path_size(path, size);
   1056   return size;
   1057 }
   1058 
   1059 //===----------------------------------------------------------------------===//
   1060 // FoldingSet profiling methods.
   1061 //===----------------------------------------------------------------------===//
   1062 
   1063 void PathDiagnosticLocation::Profile(llvm::FoldingSetNodeID &ID) const {
   1064   ID.AddInteger(Range.getBegin().getRawEncoding());
   1065   ID.AddInteger(Range.getEnd().getRawEncoding());
   1066   ID.AddInteger(Loc.getRawEncoding());
   1067   return;
   1068 }
   1069 
   1070 void PathDiagnosticPiece::Profile(llvm::FoldingSetNodeID &ID) const {
   1071   ID.AddInteger((unsigned) getKind());
   1072   ID.AddString(str);
   1073   // FIXME: Add profiling support for code hints.
   1074   ID.AddInteger((unsigned) getDisplayHint());
   1075   ArrayRef<SourceRange> Ranges = getRanges();
   1076   for (ArrayRef<SourceRange>::iterator I = Ranges.begin(), E = Ranges.end();
   1077                                         I != E; ++I) {
   1078     ID.AddInteger(I->getBegin().getRawEncoding());
   1079     ID.AddInteger(I->getEnd().getRawEncoding());
   1080   }
   1081 }
   1082 
   1083 void PathDiagnosticCallPiece::Profile(llvm::FoldingSetNodeID &ID) const {
   1084   PathDiagnosticPiece::Profile(ID);
   1085   for (PathPieces::const_iterator it = path.begin(),
   1086        et = path.end(); it != et; ++it) {
   1087     ID.Add(**it);
   1088   }
   1089 }
   1090 
   1091 void PathDiagnosticSpotPiece::Profile(llvm::FoldingSetNodeID &ID) const {
   1092   PathDiagnosticPiece::Profile(ID);
   1093   ID.Add(Pos);
   1094 }
   1095 
   1096 void PathDiagnosticControlFlowPiece::Profile(llvm::FoldingSetNodeID &ID) const {
   1097   PathDiagnosticPiece::Profile(ID);
   1098   for (const_iterator I = begin(), E = end(); I != E; ++I)
   1099     ID.Add(*I);
   1100 }
   1101 
   1102 void PathDiagnosticMacroPiece::Profile(llvm::FoldingSetNodeID &ID) const {
   1103   PathDiagnosticSpotPiece::Profile(ID);
   1104   for (PathPieces::const_iterator I = subPieces.begin(), E = subPieces.end();
   1105        I != E; ++I)
   1106     ID.Add(**I);
   1107 }
   1108 
   1109 void PathDiagnostic::Profile(llvm::FoldingSetNodeID &ID) const {
   1110   ID.Add(getLocation());
   1111   ID.AddString(BugType);
   1112   ID.AddString(VerboseDesc);
   1113   ID.AddString(Category);
   1114 }
   1115 
   1116 void PathDiagnostic::FullProfile(llvm::FoldingSetNodeID &ID) const {
   1117   Profile(ID);
   1118   for (PathPieces::const_iterator I = path.begin(), E = path.end(); I != E; ++I)
   1119     ID.Add(**I);
   1120   for (meta_iterator I = meta_begin(), E = meta_end(); I != E; ++I)
   1121     ID.AddString(*I);
   1122 }
   1123 
   1124 StackHintGenerator::~StackHintGenerator() {}
   1125 
   1126 std::string StackHintGeneratorForSymbol::getMessage(const ExplodedNode *N){
   1127   ProgramPoint P = N->getLocation();
   1128   CallExitEnd CExit = P.castAs<CallExitEnd>();
   1129 
   1130   // FIXME: Use CallEvent to abstract this over all calls.
   1131   const Stmt *CallSite = CExit.getCalleeContext()->getCallSite();
   1132   const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite);
   1133   if (!CE)
   1134     return "";
   1135 
   1136   if (!N)
   1137     return getMessageForSymbolNotFound();
   1138 
   1139   // Check if one of the parameters are set to the interesting symbol.
   1140   ProgramStateRef State = N->getState();
   1141   const LocationContext *LCtx = N->getLocationContext();
   1142   unsigned ArgIndex = 0;
   1143   for (CallExpr::const_arg_iterator I = CE->arg_begin(),
   1144                                     E = CE->arg_end(); I != E; ++I, ++ArgIndex){
   1145     SVal SV = State->getSVal(*I, LCtx);
   1146 
   1147     // Check if the variable corresponding to the symbol is passed by value.
   1148     SymbolRef AS = SV.getAsLocSymbol();
   1149     if (AS == Sym) {
   1150       return getMessageForArg(*I, ArgIndex);
   1151     }
   1152 
   1153     // Check if the parameter is a pointer to the symbol.
   1154     if (Optional<loc::MemRegionVal> Reg = SV.getAs<loc::MemRegionVal>()) {
   1155       SVal PSV = State->getSVal(Reg->getRegion());
   1156       SymbolRef AS = PSV.getAsLocSymbol();
   1157       if (AS == Sym) {
   1158         return getMessageForArg(*I, ArgIndex);
   1159       }
   1160     }
   1161   }
   1162 
   1163   // Check if we are returning the interesting symbol.
   1164   SVal SV = State->getSVal(CE, LCtx);
   1165   SymbolRef RetSym = SV.getAsLocSymbol();
   1166   if (RetSym == Sym) {
   1167     return getMessageForReturn(CE);
   1168   }
   1169 
   1170   return getMessageForSymbolNotFound();
   1171 }
   1172 
   1173 std::string StackHintGeneratorForSymbol::getMessageForArg(const Expr *ArgE,
   1174                                                           unsigned ArgIndex) {
   1175   // Printed parameters start at 1, not 0.
   1176   ++ArgIndex;
   1177 
   1178   SmallString<200> buf;
   1179   llvm::raw_svector_ostream os(buf);
   1180 
   1181   os << Msg << " via " << ArgIndex << llvm::getOrdinalSuffix(ArgIndex)
   1182      << " parameter";
   1183 
   1184   return os.str();
   1185 }
   1186