AnalysisBasedWarnings.cpp revision 039970aae2b7e59ac4de5f147dfbc3c91b275b9e 
1//=- AnalysisBasedWarnings.cpp - Sema warnings based on libAnalysis -*- 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 analysis_warnings::[Policy,Executor].
11// Together they are used by Sema to issue warnings based on inexpensive
12// static analysis algorithms in libAnalysis.
13//
14//===----------------------------------------------------------------------===//
15
16#include "clang/Sema/AnalysisBasedWarnings.h"
17#include "clang/AST/DeclCXX.h"
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/EvaluatedExprVisitor.h"
20#include "clang/AST/ExprCXX.h"
21#include "clang/AST/ExprObjC.h"
22#include "clang/AST/ParentMap.h"
23#include "clang/AST/RecursiveASTVisitor.h"
24#include "clang/AST/StmtCXX.h"
25#include "clang/AST/StmtObjC.h"
26#include "clang/AST/StmtVisitor.h"
27#include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
28#include "clang/Analysis/Analyses/Consumed.h"
29#include "clang/Analysis/Analyses/ReachableCode.h"
30#include "clang/Analysis/Analyses/ThreadSafety.h"
31#include "clang/Analysis/Analyses/UninitializedValues.h"
32#include "clang/Analysis/AnalysisContext.h"
33#include "clang/Analysis/CFG.h"
34#include "clang/Analysis/CFGStmtMap.h"
35#include "clang/Basic/SourceLocation.h"
36#include "clang/Basic/SourceManager.h"
37#include "clang/Lex/Lexer.h"
38#include "clang/Lex/Preprocessor.h"
39#include "clang/Sema/ScopeInfo.h"
40#include "clang/Sema/SemaInternal.h"
41#include "llvm/ADT/ArrayRef.h"
42#include "llvm/ADT/BitVector.h"
43#include "llvm/ADT/FoldingSet.h"
44#include "llvm/ADT/ImmutableMap.h"
45#include "llvm/ADT/MapVector.h"
46#include "llvm/ADT/PostOrderIterator.h"
47#include "llvm/ADT/SmallString.h"
48#include "llvm/ADT/SmallVector.h"
49#include "llvm/ADT/StringRef.h"
50#include "llvm/Support/Casting.h"
51#include <algorithm>
52#include <deque>
53#include <iterator>
54#include <vector>
55
56using namespace clang;
57
58//===----------------------------------------------------------------------===//
59// Unreachable code analysis.
60//===----------------------------------------------------------------------===//
61
62namespace {
63  class UnreachableCodeHandler : public reachable_code::Callback {
64    Sema &S;
65  public:
66    UnreachableCodeHandler(Sema &s) : S(s) {}
67
68    void HandleUnreachable(SourceLocation L, SourceRange R1, SourceRange R2) {
69      S.Diag(L, diag::warn_unreachable) << R1 << R2;
70    }
71  };
72}
73
74/// CheckUnreachable - Check for unreachable code.
75static void CheckUnreachable(Sema &S, AnalysisDeclContext &AC) {
76  UnreachableCodeHandler UC(S);
77  reachable_code::FindUnreachableCode(AC, UC);
78}
79
80//===----------------------------------------------------------------------===//
81// Check for missing return value.
82//===----------------------------------------------------------------------===//
83
84enum ControlFlowKind {
85  UnknownFallThrough,
86  NeverFallThrough,
87  MaybeFallThrough,
88  AlwaysFallThrough,
89  NeverFallThroughOrReturn
90};
91
92/// CheckFallThrough - Check that we don't fall off the end of a
93/// Statement that should return a value.
94///
95/// \returns AlwaysFallThrough iff we always fall off the end of the statement,
96/// MaybeFallThrough iff we might or might not fall off the end,
97/// NeverFallThroughOrReturn iff we never fall off the end of the statement or
98/// return.  We assume NeverFallThrough iff we never fall off the end of the
99/// statement but we may return.  We assume that functions not marked noreturn
100/// will return.
101static ControlFlowKind CheckFallThrough(AnalysisDeclContext &AC) {
102  CFG *cfg = AC.getCFG();
103  if (cfg == 0) return UnknownFallThrough;
104
105  // The CFG leaves in dead things, and we don't want the dead code paths to
106  // confuse us, so we mark all live things first.
107  llvm::BitVector live(cfg->getNumBlockIDs());
108  unsigned count = reachable_code::ScanReachableFromBlock(&cfg->getEntry(),
109                                                          live);
110
111  bool AddEHEdges = AC.getAddEHEdges();
112  if (!AddEHEdges && count != cfg->getNumBlockIDs())
113    // When there are things remaining dead, and we didn't add EH edges
114    // from CallExprs to the catch clauses, we have to go back and
115    // mark them as live.
116    for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) {
117      CFGBlock &b = **I;
118      if (!live[b.getBlockID()]) {
119        if (b.pred_begin() == b.pred_end()) {
120          if (b.getTerminator() && isa<CXXTryStmt>(b.getTerminator()))
121            // When not adding EH edges from calls, catch clauses
122            // can otherwise seem dead.  Avoid noting them as dead.
123            count += reachable_code::ScanReachableFromBlock(&b, live);
124          continue;
125        }
126      }
127    }
128
129  // Now we know what is live, we check the live precessors of the exit block
130  // and look for fall through paths, being careful to ignore normal returns,
131  // and exceptional paths.
132  bool HasLiveReturn = false;
133  bool HasFakeEdge = false;
134  bool HasPlainEdge = false;
135  bool HasAbnormalEdge = false;
136
137  // Ignore default cases that aren't likely to be reachable because all
138  // enums in a switch(X) have explicit case statements.
139  CFGBlock::FilterOptions FO;
140  FO.IgnoreDefaultsWithCoveredEnums = 1;
141
142  for (CFGBlock::filtered_pred_iterator
143	 I = cfg->getExit().filtered_pred_start_end(FO); I.hasMore(); ++I) {
144    const CFGBlock& B = **I;
145    if (!live[B.getBlockID()])
146      continue;
147
148    // Skip blocks which contain an element marked as no-return. They don't
149    // represent actually viable edges into the exit block, so mark them as
150    // abnormal.
151    if (B.hasNoReturnElement()) {
152      HasAbnormalEdge = true;
153      continue;
154    }
155
156    // Destructors can appear after the 'return' in the CFG.  This is
157    // normal.  We need to look pass the destructors for the return
158    // statement (if it exists).
159    CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend();
160
161    for ( ; ri != re ; ++ri)
162      if (ri->getAs<CFGStmt>())
163        break;
164
165    // No more CFGElements in the block?
166    if (ri == re) {
167      if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) {
168        HasAbnormalEdge = true;
169        continue;
170      }
171      // A labeled empty statement, or the entry block...
172      HasPlainEdge = true;
173      continue;
174    }
175
176    CFGStmt CS = ri->castAs<CFGStmt>();
177    const Stmt *S = CS.getStmt();
178    if (isa<ReturnStmt>(S)) {
179      HasLiveReturn = true;
180      continue;
181    }
182    if (isa<ObjCAtThrowStmt>(S)) {
183      HasFakeEdge = true;
184      continue;
185    }
186    if (isa<CXXThrowExpr>(S)) {
187      HasFakeEdge = true;
188      continue;
189    }
190    if (isa<MSAsmStmt>(S)) {
191      // TODO: Verify this is correct.
192      HasFakeEdge = true;
193      HasLiveReturn = true;
194      continue;
195    }
196    if (isa<CXXTryStmt>(S)) {
197      HasAbnormalEdge = true;
198      continue;
199    }
200    if (std::find(B.succ_begin(), B.succ_end(), &cfg->getExit())
201        == B.succ_end()) {
202      HasAbnormalEdge = true;
203      continue;
204    }
205
206    HasPlainEdge = true;
207  }
208  if (!HasPlainEdge) {
209    if (HasLiveReturn)
210      return NeverFallThrough;
211    return NeverFallThroughOrReturn;
212  }
213  if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
214    return MaybeFallThrough;
215  // This says AlwaysFallThrough for calls to functions that are not marked
216  // noreturn, that don't return.  If people would like this warning to be more
217  // accurate, such functions should be marked as noreturn.
218  return AlwaysFallThrough;
219}
220
221namespace {
222
223struct CheckFallThroughDiagnostics {
224  unsigned diag_MaybeFallThrough_HasNoReturn;
225  unsigned diag_MaybeFallThrough_ReturnsNonVoid;
226  unsigned diag_AlwaysFallThrough_HasNoReturn;
227  unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
228  unsigned diag_NeverFallThroughOrReturn;
229  enum { Function, Block, Lambda } funMode;
230  SourceLocation FuncLoc;
231
232  static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
233    CheckFallThroughDiagnostics D;
234    D.FuncLoc = Func->getLocation();
235    D.diag_MaybeFallThrough_HasNoReturn =
236      diag::warn_falloff_noreturn_function;
237    D.diag_MaybeFallThrough_ReturnsNonVoid =
238      diag::warn_maybe_falloff_nonvoid_function;
239    D.diag_AlwaysFallThrough_HasNoReturn =
240      diag::warn_falloff_noreturn_function;
241    D.diag_AlwaysFallThrough_ReturnsNonVoid =
242      diag::warn_falloff_nonvoid_function;
243
244    // Don't suggest that virtual functions be marked "noreturn", since they
245    // might be overridden by non-noreturn functions.
246    bool isVirtualMethod = false;
247    if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Func))
248      isVirtualMethod = Method->isVirtual();
249
250    // Don't suggest that template instantiations be marked "noreturn"
251    bool isTemplateInstantiation = false;
252    if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Func))
253      isTemplateInstantiation = Function->isTemplateInstantiation();
254
255    if (!isVirtualMethod && !isTemplateInstantiation)
256      D.diag_NeverFallThroughOrReturn =
257        diag::warn_suggest_noreturn_function;
258    else
259      D.diag_NeverFallThroughOrReturn = 0;
260
261    D.funMode = Function;
262    return D;
263  }
264
265  static CheckFallThroughDiagnostics MakeForBlock() {
266    CheckFallThroughDiagnostics D;
267    D.diag_MaybeFallThrough_HasNoReturn =
268      diag::err_noreturn_block_has_return_expr;
269    D.diag_MaybeFallThrough_ReturnsNonVoid =
270      diag::err_maybe_falloff_nonvoid_block;
271    D.diag_AlwaysFallThrough_HasNoReturn =
272      diag::err_noreturn_block_has_return_expr;
273    D.diag_AlwaysFallThrough_ReturnsNonVoid =
274      diag::err_falloff_nonvoid_block;
275    D.diag_NeverFallThroughOrReturn =
276      diag::warn_suggest_noreturn_block;
277    D.funMode = Block;
278    return D;
279  }
280
281  static CheckFallThroughDiagnostics MakeForLambda() {
282    CheckFallThroughDiagnostics D;
283    D.diag_MaybeFallThrough_HasNoReturn =
284      diag::err_noreturn_lambda_has_return_expr;
285    D.diag_MaybeFallThrough_ReturnsNonVoid =
286      diag::warn_maybe_falloff_nonvoid_lambda;
287    D.diag_AlwaysFallThrough_HasNoReturn =
288      diag::err_noreturn_lambda_has_return_expr;
289    D.diag_AlwaysFallThrough_ReturnsNonVoid =
290      diag::warn_falloff_nonvoid_lambda;
291    D.diag_NeverFallThroughOrReturn = 0;
292    D.funMode = Lambda;
293    return D;
294  }
295
296  bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
297                        bool HasNoReturn) const {
298    if (funMode == Function) {
299      return (ReturnsVoid ||
300              D.getDiagnosticLevel(diag::warn_maybe_falloff_nonvoid_function,
301                                   FuncLoc) == DiagnosticsEngine::Ignored)
302        && (!HasNoReturn ||
303            D.getDiagnosticLevel(diag::warn_noreturn_function_has_return_expr,
304                                 FuncLoc) == DiagnosticsEngine::Ignored)
305        && (!ReturnsVoid ||
306            D.getDiagnosticLevel(diag::warn_suggest_noreturn_block, FuncLoc)
307              == DiagnosticsEngine::Ignored);
308    }
309
310    // For blocks / lambdas.
311    return ReturnsVoid && !HasNoReturn
312            && ((funMode == Lambda) ||
313                D.getDiagnosticLevel(diag::warn_suggest_noreturn_block, FuncLoc)
314                  == DiagnosticsEngine::Ignored);
315  }
316};
317
318}
319
320/// CheckFallThroughForFunctionDef - Check that we don't fall off the end of a
321/// function that should return a value.  Check that we don't fall off the end
322/// of a noreturn function.  We assume that functions and blocks not marked
323/// noreturn will return.
324static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
325                                    const BlockExpr *blkExpr,
326                                    const CheckFallThroughDiagnostics& CD,
327                                    AnalysisDeclContext &AC) {
328
329  bool ReturnsVoid = false;
330  bool HasNoReturn = false;
331
332  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
333    ReturnsVoid = FD->getResultType()->isVoidType();
334    HasNoReturn = FD->isNoReturn();
335  }
336  else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
337    ReturnsVoid = MD->getResultType()->isVoidType();
338    HasNoReturn = MD->hasAttr<NoReturnAttr>();
339  }
340  else if (isa<BlockDecl>(D)) {
341    QualType BlockTy = blkExpr->getType();
342    if (const FunctionType *FT =
343          BlockTy->getPointeeType()->getAs<FunctionType>()) {
344      if (FT->getResultType()->isVoidType())
345        ReturnsVoid = true;
346      if (FT->getNoReturnAttr())
347        HasNoReturn = true;
348    }
349  }
350
351  DiagnosticsEngine &Diags = S.getDiagnostics();
352
353  // Short circuit for compilation speed.
354  if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn))
355      return;
356
357  // FIXME: Function try block
358  if (const CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) {
359    switch (CheckFallThrough(AC)) {
360      case UnknownFallThrough:
361        break;
362
363      case MaybeFallThrough:
364        if (HasNoReturn)
365          S.Diag(Compound->getRBracLoc(),
366                 CD.diag_MaybeFallThrough_HasNoReturn);
367        else if (!ReturnsVoid)
368          S.Diag(Compound->getRBracLoc(),
369                 CD.diag_MaybeFallThrough_ReturnsNonVoid);
370        break;
371      case AlwaysFallThrough:
372        if (HasNoReturn)
373          S.Diag(Compound->getRBracLoc(),
374                 CD.diag_AlwaysFallThrough_HasNoReturn);
375        else if (!ReturnsVoid)
376          S.Diag(Compound->getRBracLoc(),
377                 CD.diag_AlwaysFallThrough_ReturnsNonVoid);
378        break;
379      case NeverFallThroughOrReturn:
380        if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
381          if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
382            S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn)
383              << 0 << FD;
384          } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
385            S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn)
386              << 1 << MD;
387          } else {
388            S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn);
389          }
390        }
391        break;
392      case NeverFallThrough:
393        break;
394    }
395  }
396}
397
398//===----------------------------------------------------------------------===//
399// -Wuninitialized
400//===----------------------------------------------------------------------===//
401
402namespace {
403/// ContainsReference - A visitor class to search for references to
404/// a particular declaration (the needle) within any evaluated component of an
405/// expression (recursively).
406class ContainsReference : public EvaluatedExprVisitor<ContainsReference> {
407  bool FoundReference;
408  const DeclRefExpr *Needle;
409
410public:
411  ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
412    : EvaluatedExprVisitor<ContainsReference>(Context),
413      FoundReference(false), Needle(Needle) {}
414
415  void VisitExpr(Expr *E) {
416    // Stop evaluating if we already have a reference.
417    if (FoundReference)
418      return;
419
420    EvaluatedExprVisitor<ContainsReference>::VisitExpr(E);
421  }
422
423  void VisitDeclRefExpr(DeclRefExpr *E) {
424    if (E == Needle)
425      FoundReference = true;
426    else
427      EvaluatedExprVisitor<ContainsReference>::VisitDeclRefExpr(E);
428  }
429
430  bool doesContainReference() const { return FoundReference; }
431};
432}
433
434static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
435  QualType VariableTy = VD->getType().getCanonicalType();
436  if (VariableTy->isBlockPointerType() &&
437      !VD->hasAttr<BlocksAttr>()) {
438    S.Diag(VD->getLocation(), diag::note_block_var_fixit_add_initialization) << VD->getDeclName()
439    << FixItHint::CreateInsertion(VD->getLocation(), "__block ");
440    return true;
441  }
442
443  // Don't issue a fixit if there is already an initializer.
444  if (VD->getInit())
445    return false;
446
447  // Suggest possible initialization (if any).
448  std::string Init = S.getFixItZeroInitializerForType(VariableTy);
449  if (Init.empty())
450    return false;
451
452  // Don't suggest a fixit inside macros.
453  if (VD->getLocEnd().isMacroID())
454    return false;
455
456  SourceLocation Loc = S.PP.getLocForEndOfToken(VD->getLocEnd());
457
458  S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName()
459    << FixItHint::CreateInsertion(Loc, Init);
460  return true;
461}
462
463/// Create a fixit to remove an if-like statement, on the assumption that its
464/// condition is CondVal.
465static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then,
466                          const Stmt *Else, bool CondVal,
467                          FixItHint &Fixit1, FixItHint &Fixit2) {
468  if (CondVal) {
469    // If condition is always true, remove all but the 'then'.
470    Fixit1 = FixItHint::CreateRemoval(
471        CharSourceRange::getCharRange(If->getLocStart(),
472                                      Then->getLocStart()));
473    if (Else) {
474      SourceLocation ElseKwLoc = Lexer::getLocForEndOfToken(
475          Then->getLocEnd(), 0, S.getSourceManager(), S.getLangOpts());
476      Fixit2 = FixItHint::CreateRemoval(
477          SourceRange(ElseKwLoc, Else->getLocEnd()));
478    }
479  } else {
480    // If condition is always false, remove all but the 'else'.
481    if (Else)
482      Fixit1 = FixItHint::CreateRemoval(
483          CharSourceRange::getCharRange(If->getLocStart(),
484                                        Else->getLocStart()));
485    else
486      Fixit1 = FixItHint::CreateRemoval(If->getSourceRange());
487  }
488}
489
490/// DiagUninitUse -- Helper function to produce a diagnostic for an
491/// uninitialized use of a variable.
492static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
493                          bool IsCapturedByBlock) {
494  bool Diagnosed = false;
495
496  // Diagnose each branch which leads to a sometimes-uninitialized use.
497  for (UninitUse::branch_iterator I = Use.branch_begin(), E = Use.branch_end();
498       I != E; ++I) {
499    assert(Use.getKind() == UninitUse::Sometimes);
500
501    const Expr *User = Use.getUser();
502    const Stmt *Term = I->Terminator;
503
504    // Information used when building the diagnostic.
505    unsigned DiagKind;
506    StringRef Str;
507    SourceRange Range;
508
509    // FixIts to suppress the diagnostic by removing the dead condition.
510    // For all binary terminators, branch 0 is taken if the condition is true,
511    // and branch 1 is taken if the condition is false.
512    int RemoveDiagKind = -1;
513    const char *FixitStr =
514        S.getLangOpts().CPlusPlus ? (I->Output ? "true" : "false")
515                                  : (I->Output ? "1" : "0");
516    FixItHint Fixit1, Fixit2;
517
518    switch (Term->getStmtClass()) {
519    default:
520      // Don't know how to report this. Just fall back to 'may be used
521      // uninitialized'. This happens for range-based for, which the user
522      // can't explicitly fix.
523      // FIXME: This also happens if the first use of a variable is always
524      // uninitialized, eg "for (int n; n < 10; ++n)". We should report that
525      // with the 'is uninitialized' diagnostic.
526      continue;
527
528    // "condition is true / condition is false".
529    case Stmt::IfStmtClass: {
530      const IfStmt *IS = cast<IfStmt>(Term);
531      DiagKind = 0;
532      Str = "if";
533      Range = IS->getCond()->getSourceRange();
534      RemoveDiagKind = 0;
535      CreateIfFixit(S, IS, IS->getThen(), IS->getElse(),
536                    I->Output, Fixit1, Fixit2);
537      break;
538    }
539    case Stmt::ConditionalOperatorClass: {
540      const ConditionalOperator *CO = cast<ConditionalOperator>(Term);
541      DiagKind = 0;
542      Str = "?:";
543      Range = CO->getCond()->getSourceRange();
544      RemoveDiagKind = 0;
545      CreateIfFixit(S, CO, CO->getTrueExpr(), CO->getFalseExpr(),
546                    I->Output, Fixit1, Fixit2);
547      break;
548    }
549    case Stmt::BinaryOperatorClass: {
550      const BinaryOperator *BO = cast<BinaryOperator>(Term);
551      if (!BO->isLogicalOp())
552        continue;
553      DiagKind = 0;
554      Str = BO->getOpcodeStr();
555      Range = BO->getLHS()->getSourceRange();
556      RemoveDiagKind = 0;
557      if ((BO->getOpcode() == BO_LAnd && I->Output) ||
558          (BO->getOpcode() == BO_LOr && !I->Output))
559        // true && y -> y, false || y -> y.
560        Fixit1 = FixItHint::CreateRemoval(SourceRange(BO->getLocStart(),
561                                                      BO->getOperatorLoc()));
562      else
563        // false && y -> false, true || y -> true.
564        Fixit1 = FixItHint::CreateReplacement(BO->getSourceRange(), FixitStr);
565      break;
566    }
567
568    // "loop is entered / loop is exited".
569    case Stmt::WhileStmtClass:
570      DiagKind = 1;
571      Str = "while";
572      Range = cast<WhileStmt>(Term)->getCond()->getSourceRange();
573      RemoveDiagKind = 1;
574      Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
575      break;
576    case Stmt::ForStmtClass:
577      DiagKind = 1;
578      Str = "for";
579      Range = cast<ForStmt>(Term)->getCond()->getSourceRange();
580      RemoveDiagKind = 1;
581      if (I->Output)
582        Fixit1 = FixItHint::CreateRemoval(Range);
583      else
584        Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
585      break;
586
587    // "condition is true / loop is exited".
588    case Stmt::DoStmtClass:
589      DiagKind = 2;
590      Str = "do";
591      Range = cast<DoStmt>(Term)->getCond()->getSourceRange();
592      RemoveDiagKind = 1;
593      Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
594      break;
595
596    // "switch case is taken".
597    case Stmt::CaseStmtClass:
598      DiagKind = 3;
599      Str = "case";
600      Range = cast<CaseStmt>(Term)->getLHS()->getSourceRange();
601      break;
602    case Stmt::DefaultStmtClass:
603      DiagKind = 3;
604      Str = "default";
605      Range = cast<DefaultStmt>(Term)->getDefaultLoc();
606      break;
607    }
608
609    S.Diag(Range.getBegin(), diag::warn_sometimes_uninit_var)
610      << VD->getDeclName() << IsCapturedByBlock << DiagKind
611      << Str << I->Output << Range;
612    S.Diag(User->getLocStart(), diag::note_uninit_var_use)
613      << IsCapturedByBlock << User->getSourceRange();
614    if (RemoveDiagKind != -1)
615      S.Diag(Fixit1.RemoveRange.getBegin(), diag::note_uninit_fixit_remove_cond)
616        << RemoveDiagKind << Str << I->Output << Fixit1 << Fixit2;
617
618    Diagnosed = true;
619  }
620
621  if (!Diagnosed)
622    S.Diag(Use.getUser()->getLocStart(),
623           Use.getKind() == UninitUse::Always ? diag::warn_uninit_var
624                                              : diag::warn_maybe_uninit_var)
625        << VD->getDeclName() << IsCapturedByBlock
626        << Use.getUser()->getSourceRange();
627}
628
629/// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
630/// uninitialized variable. This manages the different forms of diagnostic
631/// emitted for particular types of uses. Returns true if the use was diagnosed
632/// as a warning. If a particular use is one we omit warnings for, returns
633/// false.
634static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
635                                     const UninitUse &Use,
636                                     bool alwaysReportSelfInit = false) {
637
638  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Use.getUser())) {
639    // Inspect the initializer of the variable declaration which is
640    // being referenced prior to its initialization. We emit
641    // specialized diagnostics for self-initialization, and we
642    // specifically avoid warning about self references which take the
643    // form of:
644    //
645    //   int x = x;
646    //
647    // This is used to indicate to GCC that 'x' is intentionally left
648    // uninitialized. Proven code paths which access 'x' in
649    // an uninitialized state after this will still warn.
650    if (const Expr *Initializer = VD->getInit()) {
651      if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
652        return false;
653
654      ContainsReference CR(S.Context, DRE);
655      CR.Visit(const_cast<Expr*>(Initializer));
656      if (CR.doesContainReference()) {
657        S.Diag(DRE->getLocStart(),
658               diag::warn_uninit_self_reference_in_init)
659          << VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
660        return true;
661      }
662    }
663
664    DiagUninitUse(S, VD, Use, false);
665  } else {
666    const BlockExpr *BE = cast<BlockExpr>(Use.getUser());
667    if (VD->getType()->isBlockPointerType() && !VD->hasAttr<BlocksAttr>())
668      S.Diag(BE->getLocStart(),
669             diag::warn_uninit_byref_blockvar_captured_by_block)
670        << VD->getDeclName();
671    else
672      DiagUninitUse(S, VD, Use, true);
673  }
674
675  // Report where the variable was declared when the use wasn't within
676  // the initializer of that declaration & we didn't already suggest
677  // an initialization fixit.
678  if (!SuggestInitializationFixit(S, VD))
679    S.Diag(VD->getLocStart(), diag::note_uninit_var_def)
680      << VD->getDeclName();
681
682  return true;
683}
684
685namespace {
686  class FallthroughMapper : public RecursiveASTVisitor<FallthroughMapper> {
687  public:
688    FallthroughMapper(Sema &S)
689      : FoundSwitchStatements(false),
690        S(S) {
691    }
692
693    bool foundSwitchStatements() const { return FoundSwitchStatements; }
694
695    void markFallthroughVisited(const AttributedStmt *Stmt) {
696      bool Found = FallthroughStmts.erase(Stmt);
697      assert(Found);
698      (void)Found;
699    }
700
701    typedef llvm::SmallPtrSet<const AttributedStmt*, 8> AttrStmts;
702
703    const AttrStmts &getFallthroughStmts() const {
704      return FallthroughStmts;
705    }
706
707    void fillReachableBlocks(CFG *Cfg) {
708      assert(ReachableBlocks.empty() && "ReachableBlocks already filled");
709      std::deque<const CFGBlock *> BlockQueue;
710
711      ReachableBlocks.insert(&Cfg->getEntry());
712      BlockQueue.push_back(&Cfg->getEntry());
713      // Mark all case blocks reachable to avoid problems with switching on
714      // constants, covered enums, etc.
715      // These blocks can contain fall-through annotations, and we don't want to
716      // issue a warn_fallthrough_attr_unreachable for them.
717      for (CFG::iterator I = Cfg->begin(), E = Cfg->end(); I != E; ++I) {
718        const CFGBlock *B = *I;
719        const Stmt *L = B->getLabel();
720        if (L && isa<SwitchCase>(L) && ReachableBlocks.insert(B))
721          BlockQueue.push_back(B);
722      }
723
724      while (!BlockQueue.empty()) {
725        const CFGBlock *P = BlockQueue.front();
726        BlockQueue.pop_front();
727        for (CFGBlock::const_succ_iterator I = P->succ_begin(),
728                                           E = P->succ_end();
729             I != E; ++I) {
730          if (*I && ReachableBlocks.insert(*I))
731            BlockQueue.push_back(*I);
732        }
733      }
734    }
735
736    bool checkFallThroughIntoBlock(const CFGBlock &B, int &AnnotatedCnt) {
737      assert(!ReachableBlocks.empty() && "ReachableBlocks empty");
738
739      int UnannotatedCnt = 0;
740      AnnotatedCnt = 0;
741
742      std::deque<const CFGBlock*> BlockQueue;
743
744      std::copy(B.pred_begin(), B.pred_end(), std::back_inserter(BlockQueue));
745
746      while (!BlockQueue.empty()) {
747        const CFGBlock *P = BlockQueue.front();
748        BlockQueue.pop_front();
749
750        const Stmt *Term = P->getTerminator();
751        if (Term && isa<SwitchStmt>(Term))
752          continue; // Switch statement, good.
753
754        const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(P->getLabel());
755        if (SW && SW->getSubStmt() == B.getLabel() && P->begin() == P->end())
756          continue; // Previous case label has no statements, good.
757
758        const LabelStmt *L = dyn_cast_or_null<LabelStmt>(P->getLabel());
759        if (L && L->getSubStmt() == B.getLabel() && P->begin() == P->end())
760          continue; // Case label is preceded with a normal label, good.
761
762        if (!ReachableBlocks.count(P)) {
763          for (CFGBlock::const_reverse_iterator ElemIt = P->rbegin(),
764                                                ElemEnd = P->rend();
765               ElemIt != ElemEnd; ++ElemIt) {
766            if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>()) {
767              if (const AttributedStmt *AS = asFallThroughAttr(CS->getStmt())) {
768                S.Diag(AS->getLocStart(),
769                       diag::warn_fallthrough_attr_unreachable);
770                markFallthroughVisited(AS);
771                ++AnnotatedCnt;
772                break;
773              }
774              // Don't care about other unreachable statements.
775            }
776          }
777          // If there are no unreachable statements, this may be a special
778          // case in CFG:
779          // case X: {
780          //    A a;  // A has a destructor.
781          //    break;
782          // }
783          // // <<<< This place is represented by a 'hanging' CFG block.
784          // case Y:
785          continue;
786        }
787
788        const Stmt *LastStmt = getLastStmt(*P);
789        if (const AttributedStmt *AS = asFallThroughAttr(LastStmt)) {
790          markFallthroughVisited(AS);
791          ++AnnotatedCnt;
792          continue; // Fallthrough annotation, good.
793        }
794
795        if (!LastStmt) { // This block contains no executable statements.
796          // Traverse its predecessors.
797          std::copy(P->pred_begin(), P->pred_end(),
798                    std::back_inserter(BlockQueue));
799          continue;
800        }
801
802        ++UnannotatedCnt;
803      }
804      return !!UnannotatedCnt;
805    }
806
807    // RecursiveASTVisitor setup.
808    bool shouldWalkTypesOfTypeLocs() const { return false; }
809
810    bool VisitAttributedStmt(AttributedStmt *S) {
811      if (asFallThroughAttr(S))
812        FallthroughStmts.insert(S);
813      return true;
814    }
815
816    bool VisitSwitchStmt(SwitchStmt *S) {
817      FoundSwitchStatements = true;
818      return true;
819    }
820
821    // We don't want to traverse local type declarations. We analyze their
822    // methods separately.
823    bool TraverseDecl(Decl *D) { return true; }
824
825  private:
826
827    static const AttributedStmt *asFallThroughAttr(const Stmt *S) {
828      if (const AttributedStmt *AS = dyn_cast_or_null<AttributedStmt>(S)) {
829        if (hasSpecificAttr<FallThroughAttr>(AS->getAttrs()))
830          return AS;
831      }
832      return 0;
833    }
834
835    static const Stmt *getLastStmt(const CFGBlock &B) {
836      if (const Stmt *Term = B.getTerminator())
837        return Term;
838      for (CFGBlock::const_reverse_iterator ElemIt = B.rbegin(),
839                                            ElemEnd = B.rend();
840                                            ElemIt != ElemEnd; ++ElemIt) {
841        if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>())
842          return CS->getStmt();
843      }
844      // Workaround to detect a statement thrown out by CFGBuilder:
845      //   case X: {} case Y:
846      //   case X: ; case Y:
847      if (const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(B.getLabel()))
848        if (!isa<SwitchCase>(SW->getSubStmt()))
849          return SW->getSubStmt();
850
851      return 0;
852    }
853
854    bool FoundSwitchStatements;
855    AttrStmts FallthroughStmts;
856    Sema &S;
857    llvm::SmallPtrSet<const CFGBlock *, 16> ReachableBlocks;
858  };
859}
860
861static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
862                                            bool PerFunction) {
863  // Only perform this analysis when using C++11.  There is no good workflow
864  // for this warning when not using C++11.  There is no good way to silence
865  // the warning (no attribute is available) unless we are using C++11's support
866  // for generalized attributes.  Once could use pragmas to silence the warning,
867  // but as a general solution that is gross and not in the spirit of this
868  // warning.
869  //
870  // NOTE: This an intermediate solution.  There are on-going discussions on
871  // how to properly support this warning outside of C++11 with an annotation.
872  if (!AC.getASTContext().getLangOpts().CPlusPlus11)
873    return;
874
875  FallthroughMapper FM(S);
876  FM.TraverseStmt(AC.getBody());
877
878  if (!FM.foundSwitchStatements())
879    return;
880
881  if (PerFunction && FM.getFallthroughStmts().empty())
882    return;
883
884  CFG *Cfg = AC.getCFG();
885
886  if (!Cfg)
887    return;
888
889  FM.fillReachableBlocks(Cfg);
890
891  for (CFG::reverse_iterator I = Cfg->rbegin(), E = Cfg->rend(); I != E; ++I) {
892    const CFGBlock *B = *I;
893    const Stmt *Label = B->getLabel();
894
895    if (!Label || !isa<SwitchCase>(Label))
896      continue;
897
898    int AnnotatedCnt;
899
900    if (!FM.checkFallThroughIntoBlock(*B, AnnotatedCnt))
901      continue;
902
903    S.Diag(Label->getLocStart(),
904        PerFunction ? diag::warn_unannotated_fallthrough_per_function
905                    : diag::warn_unannotated_fallthrough);
906
907    if (!AnnotatedCnt) {
908      SourceLocation L = Label->getLocStart();
909      if (L.isMacroID())
910        continue;
911      if (S.getLangOpts().CPlusPlus11) {
912        const Stmt *Term = B->getTerminator();
913        // Skip empty cases.
914        while (B->empty() && !Term && B->succ_size() == 1) {
915          B = *B->succ_begin();
916          Term = B->getTerminator();
917        }
918        if (!(B->empty() && Term && isa<BreakStmt>(Term))) {
919          Preprocessor &PP = S.getPreprocessor();
920          TokenValue Tokens[] = {
921            tok::l_square, tok::l_square, PP.getIdentifierInfo("clang"),
922            tok::coloncolon, PP.getIdentifierInfo("fallthrough"),
923            tok::r_square, tok::r_square
924          };
925          StringRef AnnotationSpelling = "[[clang::fallthrough]]";
926          StringRef MacroName = PP.getLastMacroWithSpelling(L, Tokens);
927          if (!MacroName.empty())
928            AnnotationSpelling = MacroName;
929          SmallString<64> TextToInsert(AnnotationSpelling);
930          TextToInsert += "; ";
931          S.Diag(L, diag::note_insert_fallthrough_fixit) <<
932              AnnotationSpelling <<
933              FixItHint::CreateInsertion(L, TextToInsert);
934        }
935      }
936      S.Diag(L, diag::note_insert_break_fixit) <<
937        FixItHint::CreateInsertion(L, "break; ");
938    }
939  }
940
941  const FallthroughMapper::AttrStmts &Fallthroughs = FM.getFallthroughStmts();
942  for (FallthroughMapper::AttrStmts::const_iterator I = Fallthroughs.begin(),
943                                                    E = Fallthroughs.end();
944                                                    I != E; ++I) {
945    S.Diag((*I)->getLocStart(), diag::warn_fallthrough_attr_invalid_placement);
946  }
947
948}
949
950namespace {
951typedef std::pair<const Stmt *,
952                  sema::FunctionScopeInfo::WeakObjectUseMap::const_iterator>
953        StmtUsesPair;
954
955class StmtUseSorter {
956  const SourceManager &SM;
957
958public:
959  explicit StmtUseSorter(const SourceManager &SM) : SM(SM) { }
960
961  bool operator()(const StmtUsesPair &LHS, const StmtUsesPair &RHS) {
962    return SM.isBeforeInTranslationUnit(LHS.first->getLocStart(),
963                                        RHS.first->getLocStart());
964  }
965};
966}
967
968static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM,
969                     const Stmt *S) {
970  assert(S);
971
972  do {
973    switch (S->getStmtClass()) {
974    case Stmt::ForStmtClass:
975    case Stmt::WhileStmtClass:
976    case Stmt::CXXForRangeStmtClass:
977    case Stmt::ObjCForCollectionStmtClass:
978      return true;
979    case Stmt::DoStmtClass: {
980      const Expr *Cond = cast<DoStmt>(S)->getCond();
981      llvm::APSInt Val;
982      if (!Cond->EvaluateAsInt(Val, Ctx))
983        return true;
984      return Val.getBoolValue();
985    }
986    default:
987      break;
988    }
989  } while ((S = PM.getParent(S)));
990
991  return false;
992}
993
994
995static void diagnoseRepeatedUseOfWeak(Sema &S,
996                                      const sema::FunctionScopeInfo *CurFn,
997                                      const Decl *D,
998                                      const ParentMap &PM) {
999  typedef sema::FunctionScopeInfo::WeakObjectProfileTy WeakObjectProfileTy;
1000  typedef sema::FunctionScopeInfo::WeakObjectUseMap WeakObjectUseMap;
1001  typedef sema::FunctionScopeInfo::WeakUseVector WeakUseVector;
1002
1003  ASTContext &Ctx = S.getASTContext();
1004
1005  const WeakObjectUseMap &WeakMap = CurFn->getWeakObjectUses();
1006
1007  // Extract all weak objects that are referenced more than once.
1008  SmallVector<StmtUsesPair, 8> UsesByStmt;
1009  for (WeakObjectUseMap::const_iterator I = WeakMap.begin(), E = WeakMap.end();
1010       I != E; ++I) {
1011    const WeakUseVector &Uses = I->second;
1012
1013    // Find the first read of the weak object.
1014    WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
1015    for ( ; UI != UE; ++UI) {
1016      if (UI->isUnsafe())
1017        break;
1018    }
1019
1020    // If there were only writes to this object, don't warn.
1021    if (UI == UE)
1022      continue;
1023
1024    // If there was only one read, followed by any number of writes, and the
1025    // read is not within a loop, don't warn. Additionally, don't warn in a
1026    // loop if the base object is a local variable -- local variables are often
1027    // changed in loops.
1028    if (UI == Uses.begin()) {
1029      WeakUseVector::const_iterator UI2 = UI;
1030      for (++UI2; UI2 != UE; ++UI2)
1031        if (UI2->isUnsafe())
1032          break;
1033
1034      if (UI2 == UE) {
1035        if (!isInLoop(Ctx, PM, UI->getUseExpr()))
1036          continue;
1037
1038        const WeakObjectProfileTy &Profile = I->first;
1039        if (!Profile.isExactProfile())
1040          continue;
1041
1042        const NamedDecl *Base = Profile.getBase();
1043        if (!Base)
1044          Base = Profile.getProperty();
1045        assert(Base && "A profile always has a base or property.");
1046
1047        if (const VarDecl *BaseVar = dyn_cast<VarDecl>(Base))
1048          if (BaseVar->hasLocalStorage() && !isa<ParmVarDecl>(Base))
1049            continue;
1050      }
1051    }
1052
1053    UsesByStmt.push_back(StmtUsesPair(UI->getUseExpr(), I));
1054  }
1055
1056  if (UsesByStmt.empty())
1057    return;
1058
1059  // Sort by first use so that we emit the warnings in a deterministic order.
1060  std::sort(UsesByStmt.begin(), UsesByStmt.end(),
1061            StmtUseSorter(S.getSourceManager()));
1062
1063  // Classify the current code body for better warning text.
1064  // This enum should stay in sync with the cases in
1065  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1066  // FIXME: Should we use a common classification enum and the same set of
1067  // possibilities all throughout Sema?
1068  enum {
1069    Function,
1070    Method,
1071    Block,
1072    Lambda
1073  } FunctionKind;
1074
1075  if (isa<sema::BlockScopeInfo>(CurFn))
1076    FunctionKind = Block;
1077  else if (isa<sema::LambdaScopeInfo>(CurFn))
1078    FunctionKind = Lambda;
1079  else if (isa<ObjCMethodDecl>(D))
1080    FunctionKind = Method;
1081  else
1082    FunctionKind = Function;
1083
1084  // Iterate through the sorted problems and emit warnings for each.
1085  for (SmallVectorImpl<StmtUsesPair>::const_iterator I = UsesByStmt.begin(),
1086                                                     E = UsesByStmt.end();
1087       I != E; ++I) {
1088    const Stmt *FirstRead = I->first;
1089    const WeakObjectProfileTy &Key = I->second->first;
1090    const WeakUseVector &Uses = I->second->second;
1091
1092    // For complicated expressions like 'a.b.c' and 'x.b.c', WeakObjectProfileTy
1093    // may not contain enough information to determine that these are different
1094    // properties. We can only be 100% sure of a repeated use in certain cases,
1095    // and we adjust the diagnostic kind accordingly so that the less certain
1096    // case can be turned off if it is too noisy.
1097    unsigned DiagKind;
1098    if (Key.isExactProfile())
1099      DiagKind = diag::warn_arc_repeated_use_of_weak;
1100    else
1101      DiagKind = diag::warn_arc_possible_repeated_use_of_weak;
1102
1103    // Classify the weak object being accessed for better warning text.
1104    // This enum should stay in sync with the cases in
1105    // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1106    enum {
1107      Variable,
1108      Property,
1109      ImplicitProperty,
1110      Ivar
1111    } ObjectKind;
1112
1113    const NamedDecl *D = Key.getProperty();
1114    if (isa<VarDecl>(D))
1115      ObjectKind = Variable;
1116    else if (isa<ObjCPropertyDecl>(D))
1117      ObjectKind = Property;
1118    else if (isa<ObjCMethodDecl>(D))
1119      ObjectKind = ImplicitProperty;
1120    else if (isa<ObjCIvarDecl>(D))
1121      ObjectKind = Ivar;
1122    else
1123      llvm_unreachable("Unexpected weak object kind!");
1124
1125    // Show the first time the object was read.
1126    S.Diag(FirstRead->getLocStart(), DiagKind)
1127      << int(ObjectKind) << D << int(FunctionKind)
1128      << FirstRead->getSourceRange();
1129
1130    // Print all the other accesses as notes.
1131    for (WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
1132         UI != UE; ++UI) {
1133      if (UI->getUseExpr() == FirstRead)
1134        continue;
1135      S.Diag(UI->getUseExpr()->getLocStart(),
1136             diag::note_arc_weak_also_accessed_here)
1137        << UI->getUseExpr()->getSourceRange();
1138    }
1139  }
1140}
1141
1142
1143namespace {
1144struct SLocSort {
1145  bool operator()(const UninitUse &a, const UninitUse &b) {
1146    // Prefer a more confident report over a less confident one.
1147    if (a.getKind() != b.getKind())
1148      return a.getKind() > b.getKind();
1149    SourceLocation aLoc = a.getUser()->getLocStart();
1150    SourceLocation bLoc = b.getUser()->getLocStart();
1151    return aLoc.getRawEncoding() < bLoc.getRawEncoding();
1152  }
1153};
1154
1155class UninitValsDiagReporter : public UninitVariablesHandler {
1156  Sema &S;
1157  typedef SmallVector<UninitUse, 2> UsesVec;
1158  typedef llvm::PointerIntPair<UsesVec *, 1, bool> MappedType;
1159  // Prefer using MapVector to DenseMap, so that iteration order will be
1160  // the same as insertion order. This is needed to obtain a deterministic
1161  // order of diagnostics when calling flushDiagnostics().
1162  typedef llvm::MapVector<const VarDecl *, MappedType> UsesMap;
1163  UsesMap *uses;
1164
1165public:
1166  UninitValsDiagReporter(Sema &S) : S(S), uses(0) {}
1167  ~UninitValsDiagReporter() {
1168    flushDiagnostics();
1169  }
1170
1171  MappedType &getUses(const VarDecl *vd) {
1172    if (!uses)
1173      uses = new UsesMap();
1174
1175    MappedType &V = (*uses)[vd];
1176    if (!V.getPointer())
1177      V.setPointer(new UsesVec());
1178
1179    return V;
1180  }
1181
1182  void handleUseOfUninitVariable(const VarDecl *vd, const UninitUse &use) {
1183    getUses(vd).getPointer()->push_back(use);
1184  }
1185
1186  void handleSelfInit(const VarDecl *vd) {
1187    getUses(vd).setInt(true);
1188  }
1189
1190  void flushDiagnostics() {
1191    if (!uses)
1192      return;
1193
1194    for (UsesMap::iterator i = uses->begin(), e = uses->end(); i != e; ++i) {
1195      const VarDecl *vd = i->first;
1196      const MappedType &V = i->second;
1197
1198      UsesVec *vec = V.getPointer();
1199      bool hasSelfInit = V.getInt();
1200
1201      // Specially handle the case where we have uses of an uninitialized
1202      // variable, but the root cause is an idiomatic self-init.  We want
1203      // to report the diagnostic at the self-init since that is the root cause.
1204      if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
1205        DiagnoseUninitializedUse(S, vd,
1206                                 UninitUse(vd->getInit()->IgnoreParenCasts(),
1207                                           /* isAlwaysUninit */ true),
1208                                 /* alwaysReportSelfInit */ true);
1209      else {
1210        // Sort the uses by their SourceLocations.  While not strictly
1211        // guaranteed to produce them in line/column order, this will provide
1212        // a stable ordering.
1213        std::sort(vec->begin(), vec->end(), SLocSort());
1214
1215        for (UsesVec::iterator vi = vec->begin(), ve = vec->end(); vi != ve;
1216             ++vi) {
1217          // If we have self-init, downgrade all uses to 'may be uninitialized'.
1218          UninitUse Use = hasSelfInit ? UninitUse(vi->getUser(), false) : *vi;
1219
1220          if (DiagnoseUninitializedUse(S, vd, Use))
1221            // Skip further diagnostics for this variable. We try to warn only
1222            // on the first point at which a variable is used uninitialized.
1223            break;
1224        }
1225      }
1226
1227      // Release the uses vector.
1228      delete vec;
1229    }
1230    delete uses;
1231  }
1232
1233private:
1234  static bool hasAlwaysUninitializedUse(const UsesVec* vec) {
1235  for (UsesVec::const_iterator i = vec->begin(), e = vec->end(); i != e; ++i) {
1236    if (i->getKind() == UninitUse::Always) {
1237      return true;
1238    }
1239  }
1240  return false;
1241}
1242};
1243}
1244
1245namespace clang {
1246namespace {
1247typedef SmallVector<PartialDiagnosticAt, 1> OptionalNotes;
1248typedef std::pair<PartialDiagnosticAt, OptionalNotes> DelayedDiag;
1249typedef std::list<DelayedDiag> DiagList;
1250
1251struct SortDiagBySourceLocation {
1252  SourceManager &SM;
1253  SortDiagBySourceLocation(SourceManager &SM) : SM(SM) {}
1254
1255  bool operator()(const DelayedDiag &left, const DelayedDiag &right) {
1256    // Although this call will be slow, this is only called when outputting
1257    // multiple warnings.
1258    return SM.isBeforeInTranslationUnit(left.first.first, right.first.first);
1259  }
1260};
1261}}
1262
1263//===----------------------------------------------------------------------===//
1264// -Wthread-safety
1265//===----------------------------------------------------------------------===//
1266namespace clang {
1267namespace thread_safety {
1268namespace {
1269class ThreadSafetyReporter : public clang::thread_safety::ThreadSafetyHandler {
1270  Sema &S;
1271  DiagList Warnings;
1272  SourceLocation FunLocation, FunEndLocation;
1273
1274  // Helper functions
1275  void warnLockMismatch(unsigned DiagID, Name LockName, SourceLocation Loc) {
1276    // Gracefully handle rare cases when the analysis can't get a more
1277    // precise source location.
1278    if (!Loc.isValid())
1279      Loc = FunLocation;
1280    PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << LockName);
1281    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1282  }
1283
1284 public:
1285  ThreadSafetyReporter(Sema &S, SourceLocation FL, SourceLocation FEL)
1286    : S(S), FunLocation(FL), FunEndLocation(FEL) {}
1287
1288  /// \brief Emit all buffered diagnostics in order of sourcelocation.
1289  /// We need to output diagnostics produced while iterating through
1290  /// the lockset in deterministic order, so this function orders diagnostics
1291  /// and outputs them.
1292  void emitDiagnostics() {
1293    Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1294    for (DiagList::iterator I = Warnings.begin(), E = Warnings.end();
1295         I != E; ++I) {
1296      S.Diag(I->first.first, I->first.second);
1297      const OptionalNotes &Notes = I->second;
1298      for (unsigned NoteI = 0, NoteN = Notes.size(); NoteI != NoteN; ++NoteI)
1299        S.Diag(Notes[NoteI].first, Notes[NoteI].second);
1300    }
1301  }
1302
1303  void handleInvalidLockExp(SourceLocation Loc) {
1304    PartialDiagnosticAt Warning(Loc,
1305                                S.PDiag(diag::warn_cannot_resolve_lock) << Loc);
1306    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1307  }
1308  void handleUnmatchedUnlock(Name LockName, SourceLocation Loc) {
1309    warnLockMismatch(diag::warn_unlock_but_no_lock, LockName, Loc);
1310  }
1311
1312  void handleDoubleLock(Name LockName, SourceLocation Loc) {
1313    warnLockMismatch(diag::warn_double_lock, LockName, Loc);
1314  }
1315
1316  void handleMutexHeldEndOfScope(Name LockName, SourceLocation LocLocked,
1317                                 SourceLocation LocEndOfScope,
1318                                 LockErrorKind LEK){
1319    unsigned DiagID = 0;
1320    switch (LEK) {
1321      case LEK_LockedSomePredecessors:
1322        DiagID = diag::warn_lock_some_predecessors;
1323        break;
1324      case LEK_LockedSomeLoopIterations:
1325        DiagID = diag::warn_expecting_lock_held_on_loop;
1326        break;
1327      case LEK_LockedAtEndOfFunction:
1328        DiagID = diag::warn_no_unlock;
1329        break;
1330      case LEK_NotLockedAtEndOfFunction:
1331        DiagID = diag::warn_expecting_locked;
1332        break;
1333    }
1334    if (LocEndOfScope.isInvalid())
1335      LocEndOfScope = FunEndLocation;
1336
1337    PartialDiagnosticAt Warning(LocEndOfScope, S.PDiag(DiagID) << LockName);
1338    if (LocLocked.isValid()) {
1339      PartialDiagnosticAt Note(LocLocked, S.PDiag(diag::note_locked_here));
1340      Warnings.push_back(DelayedDiag(Warning, OptionalNotes(1, Note)));
1341      return;
1342    }
1343    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1344  }
1345
1346
1347  void handleExclusiveAndShared(Name LockName, SourceLocation Loc1,
1348                                SourceLocation Loc2) {
1349    PartialDiagnosticAt Warning(
1350      Loc1, S.PDiag(diag::warn_lock_exclusive_and_shared) << LockName);
1351    PartialDiagnosticAt Note(
1352      Loc2, S.PDiag(diag::note_lock_exclusive_and_shared) << LockName);
1353    Warnings.push_back(DelayedDiag(Warning, OptionalNotes(1, Note)));
1354  }
1355
1356  void handleNoMutexHeld(const NamedDecl *D, ProtectedOperationKind POK,
1357                         AccessKind AK, SourceLocation Loc) {
1358    assert((POK == POK_VarAccess || POK == POK_VarDereference)
1359             && "Only works for variables");
1360    unsigned DiagID = POK == POK_VarAccess?
1361                        diag::warn_variable_requires_any_lock:
1362                        diag::warn_var_deref_requires_any_lock;
1363    PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
1364      << D->getNameAsString() << getLockKindFromAccessKind(AK));
1365    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1366  }
1367
1368  void handleMutexNotHeld(const NamedDecl *D, ProtectedOperationKind POK,
1369                          Name LockName, LockKind LK, SourceLocation Loc,
1370                          Name *PossibleMatch) {
1371    unsigned DiagID = 0;
1372    if (PossibleMatch) {
1373      switch (POK) {
1374        case POK_VarAccess:
1375          DiagID = diag::warn_variable_requires_lock_precise;
1376          break;
1377        case POK_VarDereference:
1378          DiagID = diag::warn_var_deref_requires_lock_precise;
1379          break;
1380        case POK_FunctionCall:
1381          DiagID = diag::warn_fun_requires_lock_precise;
1382          break;
1383      }
1384      PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
1385        << D->getNameAsString() << LockName << LK);
1386      PartialDiagnosticAt Note(Loc, S.PDiag(diag::note_found_mutex_near_match)
1387                               << *PossibleMatch);
1388      Warnings.push_back(DelayedDiag(Warning, OptionalNotes(1, Note)));
1389    } else {
1390      switch (POK) {
1391        case POK_VarAccess:
1392          DiagID = diag::warn_variable_requires_lock;
1393          break;
1394        case POK_VarDereference:
1395          DiagID = diag::warn_var_deref_requires_lock;
1396          break;
1397        case POK_FunctionCall:
1398          DiagID = diag::warn_fun_requires_lock;
1399          break;
1400      }
1401      PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
1402        << D->getNameAsString() << LockName << LK);
1403      Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1404    }
1405  }
1406
1407  void handleFunExcludesLock(Name FunName, Name LockName, SourceLocation Loc) {
1408    PartialDiagnosticAt Warning(Loc,
1409      S.PDiag(diag::warn_fun_excludes_mutex) << FunName << LockName);
1410    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1411  }
1412};
1413}
1414}
1415}
1416
1417//===----------------------------------------------------------------------===//
1418// -Wconsumed
1419//===----------------------------------------------------------------------===//
1420
1421namespace clang {
1422namespace consumed {
1423namespace {
1424class ConsumedWarningsHandler : public ConsumedWarningsHandlerBase {
1425
1426  Sema &S;
1427  DiagList Warnings;
1428
1429public:
1430
1431  ConsumedWarningsHandler(Sema &S) : S(S) {}
1432
1433  void emitDiagnostics() {
1434    Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1435
1436    for (DiagList::iterator I = Warnings.begin(), E = Warnings.end();
1437         I != E; ++I) {
1438
1439      const OptionalNotes &Notes = I->second;
1440      S.Diag(I->first.first, I->first.second);
1441
1442      for (unsigned NoteI = 0, NoteN = Notes.size(); NoteI != NoteN; ++NoteI) {
1443        S.Diag(Notes[NoteI].first, Notes[NoteI].second);
1444      }
1445    }
1446  }
1447
1448  /// Warn about unnecessary-test errors.
1449  /// \param VariableName -- The name of the variable that holds the unique
1450  /// value.
1451  ///
1452  /// \param Loc -- The SourceLocation of the unnecessary test.
1453  void warnUnnecessaryTest(StringRef VariableName, StringRef VariableState,
1454                           SourceLocation Loc) {
1455
1456    PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_unnecessary_test) <<
1457                                 VariableName << VariableState);
1458
1459    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1460  }
1461
1462  /// Warn about use-while-consumed errors.
1463  /// \param MethodName -- The name of the method that was incorrectly
1464  /// invoked.
1465  ///
1466  /// \param Loc -- The SourceLocation of the method invocation.
1467  void warnUseOfTempWhileConsumed(StringRef MethodName, SourceLocation Loc) {
1468
1469    PartialDiagnosticAt Warning(Loc, S.PDiag(
1470      diag::warn_use_of_temp_while_consumed) << MethodName);
1471
1472    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1473  }
1474
1475  /// Warn about use-in-unknown-state errors.
1476  /// \param MethodName -- The name of the method that was incorrectly
1477  /// invoked.
1478  ///
1479  /// \param Loc -- The SourceLocation of the method invocation.
1480  void warnUseOfTempInUnknownState(StringRef MethodName, SourceLocation Loc) {
1481
1482    PartialDiagnosticAt Warning(Loc, S.PDiag(
1483      diag::warn_use_of_temp_in_unknown_state) << MethodName);
1484
1485    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1486  }
1487
1488  /// Warn about use-while-consumed errors.
1489  /// \param MethodName -- The name of the method that was incorrectly
1490  /// invoked.
1491  ///
1492  /// \param VariableName -- The name of the variable that holds the unique
1493  /// value.
1494  ///
1495  /// \param Loc -- The SourceLocation of the method invocation.
1496  void warnUseWhileConsumed(StringRef MethodName, StringRef VariableName,
1497                            SourceLocation Loc) {
1498
1499    PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_use_while_consumed) <<
1500                                MethodName << VariableName);
1501
1502    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1503  }
1504
1505  /// Warn about use-in-unknown-state errors.
1506  /// \param MethodName -- The name of the method that was incorrectly
1507  /// invoked.
1508  ///
1509  /// \param VariableName -- The name of the variable that holds the unique
1510  /// value.
1511  ///
1512  /// \param Loc -- The SourceLocation of the method invocation.
1513  void warnUseInUnknownState(StringRef MethodName, StringRef VariableName,
1514                             SourceLocation Loc) {
1515
1516    PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_use_in_unknown_state) <<
1517                                MethodName << VariableName);
1518
1519    Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
1520  }
1521};
1522}}}
1523
1524//===----------------------------------------------------------------------===//
1525// AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
1526//  warnings on a function, method, or block.
1527//===----------------------------------------------------------------------===//
1528
1529clang::sema::AnalysisBasedWarnings::Policy::Policy() {
1530  enableCheckFallThrough = 1;
1531  enableCheckUnreachable = 0;
1532  enableThreadSafetyAnalysis = 0;
1533  enableConsumedAnalysis = 0;
1534}
1535
1536clang::sema::AnalysisBasedWarnings::AnalysisBasedWarnings(Sema &s)
1537  : S(s),
1538    NumFunctionsAnalyzed(0),
1539    NumFunctionsWithBadCFGs(0),
1540    NumCFGBlocks(0),
1541    MaxCFGBlocksPerFunction(0),
1542    NumUninitAnalysisFunctions(0),
1543    NumUninitAnalysisVariables(0),
1544    MaxUninitAnalysisVariablesPerFunction(0),
1545    NumUninitAnalysisBlockVisits(0),
1546    MaxUninitAnalysisBlockVisitsPerFunction(0) {
1547  DiagnosticsEngine &D = S.getDiagnostics();
1548  DefaultPolicy.enableCheckUnreachable = (unsigned)
1549    (D.getDiagnosticLevel(diag::warn_unreachable, SourceLocation()) !=
1550        DiagnosticsEngine::Ignored);
1551  DefaultPolicy.enableThreadSafetyAnalysis = (unsigned)
1552    (D.getDiagnosticLevel(diag::warn_double_lock, SourceLocation()) !=
1553     DiagnosticsEngine::Ignored);
1554  DefaultPolicy.enableConsumedAnalysis =
1555      (unsigned)(D.getDiagnosticLevel(diag::warn_use_while_consumed,
1556                                      SourceLocation()) !=
1557                 DiagnosticsEngine::Ignored);
1558}
1559
1560static void flushDiagnostics(Sema &S, sema::FunctionScopeInfo *fscope) {
1561  for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
1562       i = fscope->PossiblyUnreachableDiags.begin(),
1563       e = fscope->PossiblyUnreachableDiags.end();
1564       i != e; ++i) {
1565    const sema::PossiblyUnreachableDiag &D = *i;
1566    S.Diag(D.Loc, D.PD);
1567  }
1568}
1569
1570void clang::sema::
1571AnalysisBasedWarnings::IssueWarnings(sema::AnalysisBasedWarnings::Policy P,
1572                                     sema::FunctionScopeInfo *fscope,
1573                                     const Decl *D, const BlockExpr *blkExpr) {
1574
1575  // We avoid doing analysis-based warnings when there are errors for
1576  // two reasons:
1577  // (1) The CFGs often can't be constructed (if the body is invalid), so
1578  //     don't bother trying.
1579  // (2) The code already has problems; running the analysis just takes more
1580  //     time.
1581  DiagnosticsEngine &Diags = S.getDiagnostics();
1582
1583  // Do not do any analysis for declarations in system headers if we are
1584  // going to just ignore them.
1585  if (Diags.getSuppressSystemWarnings() &&
1586      S.SourceMgr.isInSystemHeader(D->getLocation()))
1587    return;
1588
1589  // For code in dependent contexts, we'll do this at instantiation time.
1590  if (cast<DeclContext>(D)->isDependentContext())
1591    return;
1592
1593  if (Diags.hasUncompilableErrorOccurred() || Diags.hasFatalErrorOccurred()) {
1594    // Flush out any possibly unreachable diagnostics.
1595    flushDiagnostics(S, fscope);
1596    return;
1597  }
1598
1599  const Stmt *Body = D->getBody();
1600  assert(Body);
1601
1602  AnalysisDeclContext AC(/* AnalysisDeclContextManager */ 0, D);
1603
1604  // Don't generate EH edges for CallExprs as we'd like to avoid the n^2
1605  // explosion for destrutors that can result and the compile time hit.
1606  AC.getCFGBuildOptions().PruneTriviallyFalseEdges = true;
1607  AC.getCFGBuildOptions().AddEHEdges = false;
1608  AC.getCFGBuildOptions().AddInitializers = true;
1609  AC.getCFGBuildOptions().AddImplicitDtors = true;
1610  AC.getCFGBuildOptions().AddTemporaryDtors = true;
1611
1612  // Force that certain expressions appear as CFGElements in the CFG.  This
1613  // is used to speed up various analyses.
1614  // FIXME: This isn't the right factoring.  This is here for initial
1615  // prototyping, but we need a way for analyses to say what expressions they
1616  // expect to always be CFGElements and then fill in the BuildOptions
1617  // appropriately.  This is essentially a layering violation.
1618  if (P.enableCheckUnreachable || P.enableThreadSafetyAnalysis ||
1619      P.enableConsumedAnalysis) {
1620    // Unreachable code analysis and thread safety require a linearized CFG.
1621    AC.getCFGBuildOptions().setAllAlwaysAdd();
1622  }
1623  else {
1624    AC.getCFGBuildOptions()
1625      .setAlwaysAdd(Stmt::BinaryOperatorClass)
1626      .setAlwaysAdd(Stmt::CompoundAssignOperatorClass)
1627      .setAlwaysAdd(Stmt::BlockExprClass)
1628      .setAlwaysAdd(Stmt::CStyleCastExprClass)
1629      .setAlwaysAdd(Stmt::DeclRefExprClass)
1630      .setAlwaysAdd(Stmt::ImplicitCastExprClass)
1631      .setAlwaysAdd(Stmt::UnaryOperatorClass)
1632      .setAlwaysAdd(Stmt::AttributedStmtClass);
1633  }
1634
1635  // Construct the analysis context with the specified CFG build options.
1636
1637  // Emit delayed diagnostics.
1638  if (!fscope->PossiblyUnreachableDiags.empty()) {
1639    bool analyzed = false;
1640
1641    // Register the expressions with the CFGBuilder.
1642    for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
1643         i = fscope->PossiblyUnreachableDiags.begin(),
1644         e = fscope->PossiblyUnreachableDiags.end();
1645         i != e; ++i) {
1646      if (const Stmt *stmt = i->stmt)
1647        AC.registerForcedBlockExpression(stmt);
1648    }
1649
1650    if (AC.getCFG()) {
1651      analyzed = true;
1652      for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
1653            i = fscope->PossiblyUnreachableDiags.begin(),
1654            e = fscope->PossiblyUnreachableDiags.end();
1655            i != e; ++i)
1656      {
1657        const sema::PossiblyUnreachableDiag &D = *i;
1658        bool processed = false;
1659        if (const Stmt *stmt = i->stmt) {
1660          const CFGBlock *block = AC.getBlockForRegisteredExpression(stmt);
1661          CFGReverseBlockReachabilityAnalysis *cra =
1662              AC.getCFGReachablityAnalysis();
1663          // FIXME: We should be able to assert that block is non-null, but
1664          // the CFG analysis can skip potentially-evaluated expressions in
1665          // edge cases; see test/Sema/vla-2.c.
1666          if (block && cra) {
1667            // Can this block be reached from the entrance?
1668            if (cra->isReachable(&AC.getCFG()->getEntry(), block))
1669              S.Diag(D.Loc, D.PD);
1670            processed = true;
1671          }
1672        }
1673        if (!processed) {
1674          // Emit the warning anyway if we cannot map to a basic block.
1675          S.Diag(D.Loc, D.PD);
1676        }
1677      }
1678    }
1679
1680    if (!analyzed)
1681      flushDiagnostics(S, fscope);
1682  }
1683
1684
1685  // Warning: check missing 'return'
1686  if (P.enableCheckFallThrough) {
1687    const CheckFallThroughDiagnostics &CD =
1688      (isa<BlockDecl>(D) ? CheckFallThroughDiagnostics::MakeForBlock()
1689       : (isa<CXXMethodDecl>(D) &&
1690          cast<CXXMethodDecl>(D)->getOverloadedOperator() == OO_Call &&
1691          cast<CXXMethodDecl>(D)->getParent()->isLambda())
1692            ? CheckFallThroughDiagnostics::MakeForLambda()
1693            : CheckFallThroughDiagnostics::MakeForFunction(D));
1694    CheckFallThroughForBody(S, D, Body, blkExpr, CD, AC);
1695  }
1696
1697  // Warning: check for unreachable code
1698  if (P.enableCheckUnreachable) {
1699    // Only check for unreachable code on non-template instantiations.
1700    // Different template instantiations can effectively change the control-flow
1701    // and it is very difficult to prove that a snippet of code in a template
1702    // is unreachable for all instantiations.
1703    bool isTemplateInstantiation = false;
1704    if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
1705      isTemplateInstantiation = Function->isTemplateInstantiation();
1706    if (!isTemplateInstantiation)
1707      CheckUnreachable(S, AC);
1708  }
1709
1710  // Check for thread safety violations
1711  if (P.enableThreadSafetyAnalysis) {
1712    SourceLocation FL = AC.getDecl()->getLocation();
1713    SourceLocation FEL = AC.getDecl()->getLocEnd();
1714    thread_safety::ThreadSafetyReporter Reporter(S, FL, FEL);
1715    if (Diags.getDiagnosticLevel(diag::warn_thread_safety_beta,D->getLocStart())
1716        != DiagnosticsEngine::Ignored)
1717      Reporter.setIssueBetaWarnings(true);
1718
1719    thread_safety::runThreadSafetyAnalysis(AC, Reporter);
1720    Reporter.emitDiagnostics();
1721  }
1722
1723  // Check for violations of consumed properties.
1724  if (P.enableConsumedAnalysis) {
1725    consumed::ConsumedWarningsHandler WarningHandler(S);
1726    consumed::ConsumedAnalyzer Analyzer(WarningHandler);
1727    Analyzer.run(AC);
1728  }
1729
1730  if (Diags.getDiagnosticLevel(diag::warn_uninit_var, D->getLocStart())
1731      != DiagnosticsEngine::Ignored ||
1732      Diags.getDiagnosticLevel(diag::warn_sometimes_uninit_var,D->getLocStart())
1733      != DiagnosticsEngine::Ignored ||
1734      Diags.getDiagnosticLevel(diag::warn_maybe_uninit_var, D->getLocStart())
1735      != DiagnosticsEngine::Ignored) {
1736    if (CFG *cfg = AC.getCFG()) {
1737      UninitValsDiagReporter reporter(S);
1738      UninitVariablesAnalysisStats stats;
1739      std::memset(&stats, 0, sizeof(UninitVariablesAnalysisStats));
1740      runUninitializedVariablesAnalysis(*cast<DeclContext>(D), *cfg, AC,
1741                                        reporter, stats);
1742
1743      if (S.CollectStats && stats.NumVariablesAnalyzed > 0) {
1744        ++NumUninitAnalysisFunctions;
1745        NumUninitAnalysisVariables += stats.NumVariablesAnalyzed;
1746        NumUninitAnalysisBlockVisits += stats.NumBlockVisits;
1747        MaxUninitAnalysisVariablesPerFunction =
1748            std::max(MaxUninitAnalysisVariablesPerFunction,
1749                     stats.NumVariablesAnalyzed);
1750        MaxUninitAnalysisBlockVisitsPerFunction =
1751            std::max(MaxUninitAnalysisBlockVisitsPerFunction,
1752                     stats.NumBlockVisits);
1753      }
1754    }
1755  }
1756
1757  bool FallThroughDiagFull =
1758      Diags.getDiagnosticLevel(diag::warn_unannotated_fallthrough,
1759                               D->getLocStart()) != DiagnosticsEngine::Ignored;
1760  bool FallThroughDiagPerFunction =
1761      Diags.getDiagnosticLevel(diag::warn_unannotated_fallthrough_per_function,
1762                               D->getLocStart()) != DiagnosticsEngine::Ignored;
1763  if (FallThroughDiagFull || FallThroughDiagPerFunction) {
1764    DiagnoseSwitchLabelsFallthrough(S, AC, !FallThroughDiagFull);
1765  }
1766
1767  if (S.getLangOpts().ObjCARCWeak &&
1768      Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak,
1769                               D->getLocStart()) != DiagnosticsEngine::Ignored)
1770    diagnoseRepeatedUseOfWeak(S, fscope, D, AC.getParentMap());
1771
1772  // Collect statistics about the CFG if it was built.
1773  if (S.CollectStats && AC.isCFGBuilt()) {
1774    ++NumFunctionsAnalyzed;
1775    if (CFG *cfg = AC.getCFG()) {
1776      // If we successfully built a CFG for this context, record some more
1777      // detail information about it.
1778      NumCFGBlocks += cfg->getNumBlockIDs();
1779      MaxCFGBlocksPerFunction = std::max(MaxCFGBlocksPerFunction,
1780                                         cfg->getNumBlockIDs());
1781    } else {
1782      ++NumFunctionsWithBadCFGs;
1783    }
1784  }
1785}
1786
1787void clang::sema::AnalysisBasedWarnings::PrintStats() const {
1788  llvm::errs() << "\n*** Analysis Based Warnings Stats:\n";
1789
1790  unsigned NumCFGsBuilt = NumFunctionsAnalyzed - NumFunctionsWithBadCFGs;
1791  unsigned AvgCFGBlocksPerFunction =
1792      !NumCFGsBuilt ? 0 : NumCFGBlocks/NumCFGsBuilt;
1793  llvm::errs() << NumFunctionsAnalyzed << " functions analyzed ("
1794               << NumFunctionsWithBadCFGs << " w/o CFGs).\n"
1795               << "  " << NumCFGBlocks << " CFG blocks built.\n"
1796               << "  " << AvgCFGBlocksPerFunction
1797               << " average CFG blocks per function.\n"
1798               << "  " << MaxCFGBlocksPerFunction
1799               << " max CFG blocks per function.\n";
1800
1801  unsigned AvgUninitVariablesPerFunction = !NumUninitAnalysisFunctions ? 0
1802      : NumUninitAnalysisVariables/NumUninitAnalysisFunctions;
1803  unsigned AvgUninitBlockVisitsPerFunction = !NumUninitAnalysisFunctions ? 0
1804      : NumUninitAnalysisBlockVisits/NumUninitAnalysisFunctions;
1805  llvm::errs() << NumUninitAnalysisFunctions
1806               << " functions analyzed for uninitialiazed variables\n"
1807               << "  " << NumUninitAnalysisVariables << " variables analyzed.\n"
1808               << "  " << AvgUninitVariablesPerFunction
1809               << " average variables per function.\n"
1810               << "  " << MaxUninitAnalysisVariablesPerFunction
1811               << " max variables per function.\n"
1812               << "  " << NumUninitAnalysisBlockVisits << " block visits.\n"
1813               << "  " << AvgUninitBlockVisitsPerFunction
1814               << " average block visits per function.\n"
1815               << "  " << MaxUninitAnalysisBlockVisitsPerFunction
1816               << " max block visits per function.\n";
1817}
1818