AnalysisConsumer.cpp revision 7fe8dcef71ae56e43fd7df345db2895f84f2d0ca 
1//===--- AnalysisConsumer.cpp - ASTConsumer for running Analyses ----------===//
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// "Meta" ASTConsumer for running different source analyses.
11//
12//===----------------------------------------------------------------------===//
13
14#define DEBUG_TYPE "AnalysisConsumer"
15
16#include "AnalysisConsumer.h"
17#include "clang/AST/ASTConsumer.h"
18#include "clang/AST/Decl.h"
19#include "clang/AST/DeclCXX.h"
20#include "clang/AST/DeclObjC.h"
21#include "clang/AST/ParentMap.h"
22#include "clang/AST/RecursiveASTVisitor.h"
23#include "clang/Analysis/CFG.h"
24#include "clang/Analysis/CallGraph.h"
25#include "clang/StaticAnalyzer/Frontend/CheckerRegistration.h"
26#include "clang/StaticAnalyzer/Core/CheckerManager.h"
27#include "clang/StaticAnalyzer/Checkers/LocalCheckers.h"
28#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
29#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
30#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
31#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
32#include "clang/StaticAnalyzer/Core/PathDiagnosticConsumers.h"
33
34#include "clang/Basic/FileManager.h"
35#include "clang/Basic/SourceManager.h"
36#include "clang/Frontend/AnalyzerOptions.h"
37#include "clang/Lex/Preprocessor.h"
38#include "llvm/Support/raw_ostream.h"
39#include "llvm/Support/Path.h"
40#include "llvm/Support/Program.h"
41#include "llvm/Support/Timer.h"
42#include "llvm/ADT/DepthFirstIterator.h"
43#include "llvm/ADT/OwningPtr.h"
44#include "llvm/ADT/Statistic.h"
45
46#include <queue>
47
48using namespace clang;
49using namespace ento;
50using llvm::SmallPtrSet;
51
52static ExplodedNode::Auditor* CreateUbiViz();
53
54STATISTIC(NumFunctionTopLevel, "The # of functions at top level.");
55STATISTIC(NumFunctionsAnalyzed, "The # of functions analysed (as top level).");
56
57//===----------------------------------------------------------------------===//
58// Special PathDiagnosticConsumers.
59//===----------------------------------------------------------------------===//
60
61static PathDiagnosticConsumer*
62createPlistHTMLDiagnosticConsumer(const std::string& prefix,
63                                const Preprocessor &PP) {
64  PathDiagnosticConsumer *PD =
65    createHTMLDiagnosticConsumer(llvm::sys::path::parent_path(prefix), PP);
66  return createPlistDiagnosticConsumer(prefix, PP, PD);
67}
68
69//===----------------------------------------------------------------------===//
70// AnalysisConsumer declaration.
71//===----------------------------------------------------------------------===//
72
73namespace {
74
75class AnalysisConsumer : public ASTConsumer,
76                         public RecursiveASTVisitor<AnalysisConsumer> {
77  enum AnalysisMode {
78    ANALYSIS_SYNTAX,
79    ANALYSIS_PATH,
80    ANALYSIS_ALL
81  };
82
83  /// Mode of the analyzes while recursively visiting Decls.
84  AnalysisMode RecVisitorMode;
85  /// Bug Reporter to use while recursively visiting Decls.
86  BugReporter *RecVisitorBR;
87
88public:
89  ASTContext *Ctx;
90  const Preprocessor &PP;
91  const std::string OutDir;
92  AnalyzerOptions Opts;
93  ArrayRef<std::string> Plugins;
94
95  // PD is owned by AnalysisManager.
96  PathDiagnosticConsumer *PD;
97
98  StoreManagerCreator CreateStoreMgr;
99  ConstraintManagerCreator CreateConstraintMgr;
100
101  OwningPtr<CheckerManager> checkerMgr;
102  OwningPtr<AnalysisManager> Mgr;
103
104  /// Time the analyzes time of each translation unit.
105  static llvm::Timer* TUTotalTimer;
106
107  AnalysisConsumer(const Preprocessor& pp,
108                   const std::string& outdir,
109                   const AnalyzerOptions& opts,
110                   ArrayRef<std::string> plugins)
111    : RecVisitorMode(ANALYSIS_ALL), RecVisitorBR(0),
112      Ctx(0), PP(pp), OutDir(outdir), Opts(opts), Plugins(plugins), PD(0) {
113    DigestAnalyzerOptions();
114    if (Opts.PrintStats) {
115      llvm::EnableStatistics();
116      TUTotalTimer = new llvm::Timer("Analyzer Total Time");
117    }
118  }
119
120  ~AnalysisConsumer() {
121    if (Opts.PrintStats)
122      delete TUTotalTimer;
123  }
124
125  void DigestAnalyzerOptions() {
126    // Create the PathDiagnosticConsumer.
127    if (!OutDir.empty()) {
128      switch (Opts.AnalysisDiagOpt) {
129      default:
130#define ANALYSIS_DIAGNOSTICS(NAME, CMDFLAG, DESC, CREATEFN, AUTOCREATE) \
131        case PD_##NAME: PD = CREATEFN(OutDir, PP); break;
132#include "clang/Frontend/Analyses.def"
133      }
134    } else if (Opts.AnalysisDiagOpt == PD_TEXT) {
135      // Create the text client even without a specified output file since
136      // it just uses diagnostic notes.
137      PD = createTextPathDiagnosticConsumer("", PP);
138    }
139
140    // Create the analyzer component creators.
141    switch (Opts.AnalysisStoreOpt) {
142    default:
143      llvm_unreachable("Unknown store manager.");
144#define ANALYSIS_STORE(NAME, CMDFLAG, DESC, CREATEFN)           \
145      case NAME##Model: CreateStoreMgr = CREATEFN; break;
146#include "clang/Frontend/Analyses.def"
147    }
148
149    switch (Opts.AnalysisConstraintsOpt) {
150    default:
151      llvm_unreachable("Unknown store manager.");
152#define ANALYSIS_CONSTRAINTS(NAME, CMDFLAG, DESC, CREATEFN)     \
153      case NAME##Model: CreateConstraintMgr = CREATEFN; break;
154#include "clang/Frontend/Analyses.def"
155    }
156  }
157
158  void DisplayFunction(const Decl *D, AnalysisMode Mode) {
159    if (!Opts.AnalyzerDisplayProgress)
160      return;
161
162    SourceManager &SM = Mgr->getASTContext().getSourceManager();
163    PresumedLoc Loc = SM.getPresumedLoc(D->getLocation());
164    if (Loc.isValid()) {
165      llvm::errs() << "ANALYZE";
166      switch (Mode) {
167        case ANALYSIS_SYNTAX: llvm::errs() << "(Syntax)"; break;
168        case ANALYSIS_PATH: llvm::errs() << "(Path Sensitive)"; break;
169        case ANALYSIS_ALL: break;
170      };
171      llvm::errs() << ": " << Loc.getFilename();
172      if (isa<FunctionDecl>(D) || isa<ObjCMethodDecl>(D)) {
173        const NamedDecl *ND = cast<NamedDecl>(D);
174        llvm::errs() << ' ' << *ND << '\n';
175      }
176      else if (isa<BlockDecl>(D)) {
177        llvm::errs() << ' ' << "block(line:" << Loc.getLine() << ",col:"
178                     << Loc.getColumn() << '\n';
179      }
180      else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
181        Selector S = MD->getSelector();
182        llvm::errs() << ' ' << S.getAsString();
183      }
184    }
185  }
186
187  virtual void Initialize(ASTContext &Context) {
188    Ctx = &Context;
189    checkerMgr.reset(createCheckerManager(Opts, PP.getLangOpts(), Plugins,
190                                          PP.getDiagnostics()));
191    Mgr.reset(new AnalysisManager(*Ctx, PP.getDiagnostics(),
192                                  PP.getLangOpts(), PD,
193                                  CreateStoreMgr, CreateConstraintMgr,
194                                  checkerMgr.get(),
195                                  /* Indexer */ 0,
196                                  Opts.MaxNodes, Opts.MaxLoop,
197                                  Opts.VisualizeEGDot, Opts.VisualizeEGUbi,
198                                  Opts.AnalysisPurgeOpt, Opts.EagerlyAssume,
199                                  Opts.TrimGraph,
200                                  Opts.UnoptimizedCFG, Opts.CFGAddImplicitDtors,
201                                  Opts.CFGAddInitializers,
202                                  Opts.EagerlyTrimEGraph,
203                                  Opts.IPAMode,
204                                  Opts.InlineMaxStackDepth,
205                                  Opts.InlineMaxFunctionSize,
206                                  Opts.InliningMode));
207  }
208
209  virtual void HandleTranslationUnit(ASTContext &C);
210
211  /// \brief Build the call graph for the TU and use it to define the order
212  /// in which the functions should be visited.
213  void HandleDeclsGallGraph(TranslationUnitDecl *TU);
214
215  /// \brief Run analyzes(syntax or path sensitive) on the given function.
216  /// \param Mode - determines if we are requesting syntax only or path
217  /// sensitive only analysis.
218  /// \param VisitedCallees - The output parameter, which is populated with the
219  /// set of functions which should be considered analyzed after analyzing the
220  /// given root function.
221  void HandleCode(Decl *D, AnalysisMode Mode, SetOfDecls *VisitedCallees = 0);
222
223  /// \brief Check if we should skip (not analyze) the given function.
224  bool skipFunction(Decl *D);
225
226  void RunPathSensitiveChecks(Decl *D, SetOfDecls *VisitedCallees);
227  void ActionExprEngine(Decl *D, bool ObjCGCEnabled, SetOfDecls *VisitedCallees);
228
229  /// Visitors for the RecursiveASTVisitor.
230
231  /// Handle callbacks for arbitrary Decls.
232  bool VisitDecl(Decl *D) {
233    checkerMgr->runCheckersOnASTDecl(D, *Mgr, *RecVisitorBR);
234    return true;
235  }
236
237  bool VisitFunctionDecl(FunctionDecl *FD) {
238    IdentifierInfo *II = FD->getIdentifier();
239    if (II && II->getName().startswith("__inline"))
240      return true;
241
242    // We skip function template definitions, as their semantics is
243    // only determined when they are instantiated.
244    if (FD->isThisDeclarationADefinition() &&
245        !FD->isDependentContext()) {
246      HandleCode(FD, RecVisitorMode);
247    }
248    return true;
249  }
250
251  bool VisitObjCMethodDecl(ObjCMethodDecl *MD) {
252    checkerMgr->runCheckersOnASTDecl(MD, *Mgr, *RecVisitorBR);
253    if (MD->isThisDeclarationADefinition())
254      HandleCode(MD, RecVisitorMode);
255    return true;
256  }
257};
258} // end anonymous namespace
259
260
261//===----------------------------------------------------------------------===//
262// AnalysisConsumer implementation.
263//===----------------------------------------------------------------------===//
264llvm::Timer* AnalysisConsumer::TUTotalTimer = 0;
265
266void AnalysisConsumer::HandleDeclsGallGraph(TranslationUnitDecl *TU) {
267  // Otherwise, use the Callgraph to derive the order.
268  // Build the Call Graph.
269  CallGraph CG;
270  CG.addToCallGraph(TU);
271
272  // Find the top level nodes - children of root + the unreachable (parentless)
273  // nodes.
274  llvm::SmallVector<CallGraphNode*, 24> TopLevelFunctions;
275  CallGraphNode *Entry = CG.getRoot();
276  for (CallGraphNode::iterator I = Entry->begin(),
277                               E = Entry->end(); I != E; ++I) {
278    TopLevelFunctions.push_back(*I);
279    NumFunctionTopLevel++;
280  }
281  for (CallGraph::nodes_iterator TI = CG.parentless_begin(),
282                                 TE = CG.parentless_end(); TI != TE; ++TI) {
283    TopLevelFunctions.push_back(*TI);
284    NumFunctionTopLevel++;
285  }
286
287  std::queue<CallGraphNode*> BFSQueue;
288  for (llvm::SmallVector<CallGraphNode*, 24>::iterator
289         TI = TopLevelFunctions.begin(), TE = TopLevelFunctions.end();
290         TI != TE; ++TI)
291    BFSQueue.push(*TI);
292
293  // BFS over all of the functions, while skipping the ones inlined into
294  // the previously processed functions. Use external Visited set, which is
295  // also modified when we inline a function.
296  SmallPtrSet<CallGraphNode*,24> Visited;
297  while(!BFSQueue.empty()) {
298    CallGraphNode *N = BFSQueue.front();
299    BFSQueue.pop();
300
301    // Skip the functions which have been processed already or previously
302    // inlined.
303    if (Visited.count(N))
304      continue;
305
306    // Analyze the function.
307    SetOfDecls VisitedCallees;
308    Decl *D = N->getDecl();
309    assert(D);
310    HandleCode(D, ANALYSIS_PATH,
311               (Mgr->InliningMode == All ? 0 : &VisitedCallees));
312
313    // Add the visited callees to the global visited set.
314    for (SetOfDecls::const_iterator I = VisitedCallees.begin(),
315                                    E = VisitedCallees.end(); I != E; ++I) {
316      CallGraphNode *VN = CG.getNode(*I);
317      if (VN)
318        Visited.insert(VN);
319    }
320    Visited.insert(N);
321
322    // Push the children into the queue.
323    for (CallGraphNode::const_iterator CI = N->begin(),
324                                       CE = N->end(); CI != CE; ++CI) {
325      BFSQueue.push(*CI);
326    }
327  }
328}
329
330void AnalysisConsumer::HandleTranslationUnit(ASTContext &C) {
331  // Don't run the actions if an error has occurred with parsing the file.
332  DiagnosticsEngine &Diags = PP.getDiagnostics();
333  if (Diags.hasErrorOccurred() || Diags.hasFatalErrorOccurred())
334    return;
335
336  {
337    if (TUTotalTimer) TUTotalTimer->startTimer();
338
339    // Introduce a scope to destroy BR before Mgr.
340    BugReporter BR(*Mgr);
341    TranslationUnitDecl *TU = C.getTranslationUnitDecl();
342    checkerMgr->runCheckersOnASTDecl(TU, *Mgr, BR);
343
344    // Run the AST-only checks using the order in which functions are defined.
345    // If inlining is not turned on, use the simplest function order for path
346    // sensitive analyzes as well.
347    RecVisitorMode = (Mgr->shouldInlineCall() ? ANALYSIS_SYNTAX : ANALYSIS_ALL);
348    RecVisitorBR = &BR;
349    TraverseDecl(TU);
350
351    if (Mgr->shouldInlineCall())
352      HandleDeclsGallGraph(TU);
353
354    // After all decls handled, run checkers on the entire TranslationUnit.
355    checkerMgr->runCheckersOnEndOfTranslationUnit(TU, *Mgr, BR);
356
357    RecVisitorBR = 0;
358  }
359
360  // Explicitly destroy the PathDiagnosticConsumer.  This will flush its output.
361  // FIXME: This should be replaced with something that doesn't rely on
362  // side-effects in PathDiagnosticConsumer's destructor. This is required when
363  // used with option -disable-free.
364  Mgr.reset(NULL);
365
366  if (TUTotalTimer) TUTotalTimer->stopTimer();
367}
368
369static void FindBlocks(DeclContext *D, SmallVectorImpl<Decl*> &WL) {
370  if (BlockDecl *BD = dyn_cast<BlockDecl>(D))
371    WL.push_back(BD);
372
373  for (DeclContext::decl_iterator I = D->decls_begin(), E = D->decls_end();
374       I!=E; ++I)
375    if (DeclContext *DC = dyn_cast<DeclContext>(*I))
376      FindBlocks(DC, WL);
377}
378
379static std::string getFunctionName(const Decl *D) {
380  if (const ObjCMethodDecl *ID = dyn_cast<ObjCMethodDecl>(D)) {
381    return ID->getSelector().getAsString();
382  }
383  if (const FunctionDecl *ND = dyn_cast<FunctionDecl>(D)) {
384    IdentifierInfo *II = ND->getIdentifier();
385    if (II)
386      return II->getName();
387  }
388  return "";
389}
390
391bool AnalysisConsumer::skipFunction(Decl *D) {
392  if (!Opts.AnalyzeSpecificFunction.empty() &&
393      getFunctionName(D) != Opts.AnalyzeSpecificFunction)
394    return true;
395
396  // Don't run the actions on declarations in header files unless
397  // otherwise specified.
398  SourceManager &SM = Ctx->getSourceManager();
399  SourceLocation SL = SM.getExpansionLoc(D->getLocation());
400  if (!Opts.AnalyzeAll && !SM.isFromMainFile(SL))
401    return true;
402
403  return false;
404}
405
406void AnalysisConsumer::HandleCode(Decl *D, AnalysisMode Mode,
407                                  SetOfDecls *VisitedCallees) {
408  if (skipFunction(D))
409    return;
410
411  DisplayFunction(D, Mode);
412
413  // Clear the AnalysisManager of old AnalysisDeclContexts.
414  Mgr->ClearContexts();
415
416  // Dispatch on the actions.
417  SmallVector<Decl*, 10> WL;
418  WL.push_back(D);
419
420  if (D->hasBody() && Opts.AnalyzeNestedBlocks)
421    FindBlocks(cast<DeclContext>(D), WL);
422
423  BugReporter BR(*Mgr);
424  for (SmallVectorImpl<Decl*>::iterator WI=WL.begin(), WE=WL.end();
425       WI != WE; ++WI)
426    if ((*WI)->hasBody()) {
427      if (Mode != ANALYSIS_PATH)
428        checkerMgr->runCheckersOnASTBody(*WI, *Mgr, BR);
429      if (Mode != ANALYSIS_SYNTAX && checkerMgr->hasPathSensitiveCheckers())
430        RunPathSensitiveChecks(*WI, VisitedCallees);
431    }
432  NumFunctionsAnalyzed++;
433}
434
435//===----------------------------------------------------------------------===//
436// Path-sensitive checking.
437//===----------------------------------------------------------------------===//
438
439void AnalysisConsumer::ActionExprEngine(Decl *D, bool ObjCGCEnabled,
440                                        SetOfDecls *VisitedCallees) {
441  // Construct the analysis engine.  First check if the CFG is valid.
442  // FIXME: Inter-procedural analysis will need to handle invalid CFGs.
443  if (!Mgr->getCFG(D))
444    return;
445
446  ExprEngine Eng(*Mgr, ObjCGCEnabled, VisitedCallees);
447
448  // Set the graph auditor.
449  OwningPtr<ExplodedNode::Auditor> Auditor;
450  if (Mgr->shouldVisualizeUbigraph()) {
451    Auditor.reset(CreateUbiViz());
452    ExplodedNode::SetAuditor(Auditor.get());
453  }
454
455  // Execute the worklist algorithm.
456  Eng.ExecuteWorkList(Mgr->getAnalysisDeclContextManager().getStackFrame(D, 0),
457                      Mgr->getMaxNodes());
458
459  // Release the auditor (if any) so that it doesn't monitor the graph
460  // created BugReporter.
461  ExplodedNode::SetAuditor(0);
462
463  // Visualize the exploded graph.
464  if (Mgr->shouldVisualizeGraphviz())
465    Eng.ViewGraph(Mgr->shouldTrimGraph());
466
467  // Display warnings.
468  Eng.getBugReporter().FlushReports();
469}
470
471void AnalysisConsumer::RunPathSensitiveChecks(Decl *D, SetOfDecls *Visited) {
472
473  switch (Mgr->getLangOpts().getGC()) {
474  case LangOptions::NonGC:
475    ActionExprEngine(D, false, Visited);
476    break;
477
478  case LangOptions::GCOnly:
479    ActionExprEngine(D, true, Visited);
480    break;
481
482  case LangOptions::HybridGC:
483    ActionExprEngine(D, false, Visited);
484    ActionExprEngine(D, true, Visited);
485    break;
486  }
487}
488
489//===----------------------------------------------------------------------===//
490// AnalysisConsumer creation.
491//===----------------------------------------------------------------------===//
492
493ASTConsumer* ento::CreateAnalysisConsumer(const Preprocessor& pp,
494                                          const std::string& outDir,
495                                          const AnalyzerOptions& opts,
496                                          ArrayRef<std::string> plugins) {
497  // Disable the effects of '-Werror' when using the AnalysisConsumer.
498  pp.getDiagnostics().setWarningsAsErrors(false);
499
500  return new AnalysisConsumer(pp, outDir, opts, plugins);
501}
502
503//===----------------------------------------------------------------------===//
504// Ubigraph Visualization.  FIXME: Move to separate file.
505//===----------------------------------------------------------------------===//
506
507namespace {
508
509class UbigraphViz : public ExplodedNode::Auditor {
510  OwningPtr<raw_ostream> Out;
511  llvm::sys::Path Dir, Filename;
512  unsigned Cntr;
513
514  typedef llvm::DenseMap<void*,unsigned> VMap;
515  VMap M;
516
517public:
518  UbigraphViz(raw_ostream *out, llvm::sys::Path& dir,
519              llvm::sys::Path& filename);
520
521  ~UbigraphViz();
522
523  virtual void AddEdge(ExplodedNode *Src, ExplodedNode *Dst);
524};
525
526} // end anonymous namespace
527
528static ExplodedNode::Auditor* CreateUbiViz() {
529  std::string ErrMsg;
530
531  llvm::sys::Path Dir = llvm::sys::Path::GetTemporaryDirectory(&ErrMsg);
532  if (!ErrMsg.empty())
533    return 0;
534
535  llvm::sys::Path Filename = Dir;
536  Filename.appendComponent("llvm_ubi");
537  Filename.makeUnique(true,&ErrMsg);
538
539  if (!ErrMsg.empty())
540    return 0;
541
542  llvm::errs() << "Writing '" << Filename.str() << "'.\n";
543
544  OwningPtr<llvm::raw_fd_ostream> Stream;
545  Stream.reset(new llvm::raw_fd_ostream(Filename.c_str(), ErrMsg));
546
547  if (!ErrMsg.empty())
548    return 0;
549
550  return new UbigraphViz(Stream.take(), Dir, Filename);
551}
552
553void UbigraphViz::AddEdge(ExplodedNode *Src, ExplodedNode *Dst) {
554
555  assert (Src != Dst && "Self-edges are not allowed.");
556
557  // Lookup the Src.  If it is a new node, it's a root.
558  VMap::iterator SrcI= M.find(Src);
559  unsigned SrcID;
560
561  if (SrcI == M.end()) {
562    M[Src] = SrcID = Cntr++;
563    *Out << "('vertex', " << SrcID << ", ('color','#00ff00'))\n";
564  }
565  else
566    SrcID = SrcI->second;
567
568  // Lookup the Dst.
569  VMap::iterator DstI= M.find(Dst);
570  unsigned DstID;
571
572  if (DstI == M.end()) {
573    M[Dst] = DstID = Cntr++;
574    *Out << "('vertex', " << DstID << ")\n";
575  }
576  else {
577    // We have hit DstID before.  Change its style to reflect a cache hit.
578    DstID = DstI->second;
579    *Out << "('change_vertex_style', " << DstID << ", 1)\n";
580  }
581
582  // Add the edge.
583  *Out << "('edge', " << SrcID << ", " << DstID
584       << ", ('arrow','true'), ('oriented', 'true'))\n";
585}
586
587UbigraphViz::UbigraphViz(raw_ostream *out, llvm::sys::Path& dir,
588                         llvm::sys::Path& filename)
589  : Out(out), Dir(dir), Filename(filename), Cntr(0) {
590
591  *Out << "('vertex_style_attribute', 0, ('shape', 'icosahedron'))\n";
592  *Out << "('vertex_style', 1, 0, ('shape', 'sphere'), ('color', '#ffcc66'),"
593          " ('size', '1.5'))\n";
594}
595
596UbigraphViz::~UbigraphViz() {
597  Out.reset(0);
598  llvm::errs() << "Running 'ubiviz' program... ";
599  std::string ErrMsg;
600  llvm::sys::Path Ubiviz = llvm::sys::Program::FindProgramByName("ubiviz");
601  std::vector<const char*> args;
602  args.push_back(Ubiviz.c_str());
603  args.push_back(Filename.c_str());
604  args.push_back(0);
605
606  if (llvm::sys::Program::ExecuteAndWait(Ubiviz, &args[0],0,0,0,0,&ErrMsg)) {
607    llvm::errs() << "Error viewing graph: " << ErrMsg << "\n";
608  }
609
610  // Delete the directory.
611  Dir.eraseFromDisk(true);
612}
613