clang  7.0.0svn
AnalysisBasedWarnings.cpp
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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 
17 #include "clang/AST/DeclCXX.h"
18 #include "clang/AST/DeclObjC.h"
20 #include "clang/AST/ExprCXX.h"
21 #include "clang/AST/ExprObjC.h"
22 #include "clang/AST/ParentMap.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/AST/StmtObjC.h"
26 #include "clang/AST/StmtVisitor.h"
33 #include "clang/Analysis/CFG.h"
37 #include "clang/Lex/Preprocessor.h"
38 #include "clang/Sema/ScopeInfo.h"
40 #include "llvm/ADT/BitVector.h"
41 #include "llvm/ADT/MapVector.h"
42 #include "llvm/ADT/SmallString.h"
43 #include "llvm/ADT/SmallVector.h"
44 #include "llvm/ADT/StringRef.h"
45 #include "llvm/Support/Casting.h"
46 #include <algorithm>
47 #include <deque>
48 #include <iterator>
49 
50 using namespace clang;
51 
52 //===----------------------------------------------------------------------===//
53 // Unreachable code analysis.
54 //===----------------------------------------------------------------------===//
55 
56 namespace {
57  class UnreachableCodeHandler : public reachable_code::Callback {
58  Sema &S;
59  SourceRange PreviousSilenceableCondVal;
60 
61  public:
62  UnreachableCodeHandler(Sema &s) : S(s) {}
63 
64  void HandleUnreachable(reachable_code::UnreachableKind UK,
66  SourceRange SilenceableCondVal,
67  SourceRange R1,
68  SourceRange R2) override {
69  // Avoid reporting multiple unreachable code diagnostics that are
70  // triggered by the same conditional value.
71  if (PreviousSilenceableCondVal.isValid() &&
72  SilenceableCondVal.isValid() &&
73  PreviousSilenceableCondVal == SilenceableCondVal)
74  return;
75  PreviousSilenceableCondVal = SilenceableCondVal;
76 
77  unsigned diag = diag::warn_unreachable;
78  switch (UK) {
80  diag = diag::warn_unreachable_break;
81  break;
83  diag = diag::warn_unreachable_return;
84  break;
86  diag = diag::warn_unreachable_loop_increment;
87  break;
89  break;
90  }
91 
92  S.Diag(L, diag) << R1 << R2;
93 
94  SourceLocation Open = SilenceableCondVal.getBegin();
95  if (Open.isValid()) {
96  SourceLocation Close = SilenceableCondVal.getEnd();
97  Close = S.getLocForEndOfToken(Close);
98  if (Close.isValid()) {
99  S.Diag(Open, diag::note_unreachable_silence)
100  << FixItHint::CreateInsertion(Open, "/* DISABLES CODE */ (")
101  << FixItHint::CreateInsertion(Close, ")");
102  }
103  }
104  }
105  };
106 } // anonymous namespace
107 
108 /// CheckUnreachable - Check for unreachable code.
110  // As a heuristic prune all diagnostics not in the main file. Currently
111  // the majority of warnings in headers are false positives. These
112  // are largely caused by configuration state, e.g. preprocessor
113  // defined code, etc.
114  //
115  // Note that this is also a performance optimization. Analyzing
116  // headers many times can be expensive.
118  return;
119 
120  UnreachableCodeHandler UC(S);
122 }
123 
124 namespace {
125 /// Warn on logical operator errors in CFGBuilder
126 class LogicalErrorHandler : public CFGCallback {
127  Sema &S;
128 
129 public:
130  LogicalErrorHandler(Sema &S) : CFGCallback(), S(S) {}
131 
132  static bool HasMacroID(const Expr *E) {
133  if (E->getExprLoc().isMacroID())
134  return true;
135 
136  // Recurse to children.
137  for (const Stmt *SubStmt : E->children())
138  if (const Expr *SubExpr = dyn_cast_or_null<Expr>(SubStmt))
139  if (HasMacroID(SubExpr))
140  return true;
141 
142  return false;
143  }
144 
145  void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue) override {
146  if (HasMacroID(B))
147  return;
148 
149  SourceRange DiagRange = B->getSourceRange();
150  S.Diag(B->getExprLoc(), diag::warn_tautological_overlap_comparison)
151  << DiagRange << isAlwaysTrue;
152  }
153 
154  void compareBitwiseEquality(const BinaryOperator *B,
155  bool isAlwaysTrue) override {
156  if (HasMacroID(B))
157  return;
158 
159  SourceRange DiagRange = B->getSourceRange();
160  S.Diag(B->getExprLoc(), diag::warn_comparison_bitwise_always)
161  << DiagRange << isAlwaysTrue;
162  }
163 };
164 } // anonymous namespace
165 
166 //===----------------------------------------------------------------------===//
167 // Check for infinite self-recursion in functions
168 //===----------------------------------------------------------------------===//
169 
170 // Returns true if the function is called anywhere within the CFGBlock.
171 // For member functions, the additional condition of being call from the
172 // this pointer is required.
173 static bool hasRecursiveCallInPath(const FunctionDecl *FD, CFGBlock &Block) {
174  // Process all the Stmt's in this block to find any calls to FD.
175  for (const auto &B : Block) {
176  if (B.getKind() != CFGElement::Statement)
177  continue;
178 
179  const CallExpr *CE = dyn_cast<CallExpr>(B.getAs<CFGStmt>()->getStmt());
180  if (!CE || !CE->getCalleeDecl() ||
181  CE->getCalleeDecl()->getCanonicalDecl() != FD)
182  continue;
183 
184  // Skip function calls which are qualified with a templated class.
185  if (const DeclRefExpr *DRE =
186  dyn_cast<DeclRefExpr>(CE->getCallee()->IgnoreParenImpCasts())) {
187  if (NestedNameSpecifier *NNS = DRE->getQualifier()) {
188  if (NNS->getKind() == NestedNameSpecifier::TypeSpec &&
189  isa<TemplateSpecializationType>(NNS->getAsType())) {
190  continue;
191  }
192  }
193  }
194 
195  const CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(CE);
196  if (!MCE || isa<CXXThisExpr>(MCE->getImplicitObjectArgument()) ||
197  !MCE->getMethodDecl()->isVirtual())
198  return true;
199  }
200  return false;
201 }
202 
203 // Returns true if every path from the entry block passes through a call to FD.
204 static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg) {
205  llvm::SmallPtrSet<CFGBlock *, 16> Visited;
207  // Keep track of whether we found at least one recursive path.
208  bool foundRecursion = false;
209 
210  const unsigned ExitID = cfg->getExit().getBlockID();
211 
212  // Seed the work list with the entry block.
213  WorkList.push_back(&cfg->getEntry());
214 
215  while (!WorkList.empty()) {
216  CFGBlock *Block = WorkList.pop_back_val();
217 
218  for (auto I = Block->succ_begin(), E = Block->succ_end(); I != E; ++I) {
219  if (CFGBlock *SuccBlock = *I) {
220  if (!Visited.insert(SuccBlock).second)
221  continue;
222 
223  // Found a path to the exit node without a recursive call.
224  if (ExitID == SuccBlock->getBlockID())
225  return false;
226 
227  // If the successor block contains a recursive call, end analysis there.
228  if (hasRecursiveCallInPath(FD, *SuccBlock)) {
229  foundRecursion = true;
230  continue;
231  }
232 
233  WorkList.push_back(SuccBlock);
234  }
235  }
236  }
237  return foundRecursion;
238 }
239 
240 static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD,
241  const Stmt *Body, AnalysisDeclContext &AC) {
242  FD = FD->getCanonicalDecl();
243 
244  // Only run on non-templated functions and non-templated members of
245  // templated classes.
248  return;
249 
250  CFG *cfg = AC.getCFG();
251  if (!cfg) return;
252 
253  // Emit diagnostic if a recursive function call is detected for all paths.
254  if (checkForRecursiveFunctionCall(FD, cfg))
255  S.Diag(Body->getLocStart(), diag::warn_infinite_recursive_function);
256 }
257 
258 //===----------------------------------------------------------------------===//
259 // Check for throw in a non-throwing function.
260 //===----------------------------------------------------------------------===//
261 
262 /// Determine whether an exception thrown by E, unwinding from ThrowBlock,
263 /// can reach ExitBlock.
264 static bool throwEscapes(Sema &S, const CXXThrowExpr *E, CFGBlock &ThrowBlock,
265  CFG *Body) {
267  llvm::BitVector Queued(Body->getNumBlockIDs());
268 
269  Stack.push_back(&ThrowBlock);
270  Queued[ThrowBlock.getBlockID()] = true;
271 
272  while (!Stack.empty()) {
273  CFGBlock &UnwindBlock = *Stack.back();
274  Stack.pop_back();
275 
276  for (auto &Succ : UnwindBlock.succs()) {
277  if (!Succ.isReachable() || Queued[Succ->getBlockID()])
278  continue;
279 
280  if (Succ->getBlockID() == Body->getExit().getBlockID())
281  return true;
282 
283  if (auto *Catch =
284  dyn_cast_or_null<CXXCatchStmt>(Succ->getLabel())) {
285  QualType Caught = Catch->getCaughtType();
286  if (Caught.isNull() || // catch (...) catches everything
287  !E->getSubExpr() || // throw; is considered cuaght by any handler
288  S.handlerCanCatch(Caught, E->getSubExpr()->getType()))
289  // Exception doesn't escape via this path.
290  break;
291  } else {
292  Stack.push_back(Succ);
293  Queued[Succ->getBlockID()] = true;
294  }
295  }
296  }
297 
298  return false;
299 }
300 
302  CFG *BodyCFG,
303  llvm::function_ref<void(const CXXThrowExpr *, CFGBlock &)> Visit) {
304  llvm::BitVector Reachable(BodyCFG->getNumBlockIDs());
306  for (CFGBlock *B : *BodyCFG) {
307  if (!Reachable[B->getBlockID()])
308  continue;
309  for (CFGElement &E : *B) {
310  Optional<CFGStmt> S = E.getAs<CFGStmt>();
311  if (!S)
312  continue;
313  if (auto *Throw = dyn_cast<CXXThrowExpr>(S->getStmt()))
314  Visit(Throw, *B);
315  }
316  }
317 }
318 
320  const FunctionDecl *FD) {
321  if (!S.getSourceManager().isInSystemHeader(OpLoc) &&
322  FD->getTypeSourceInfo()) {
323  S.Diag(OpLoc, diag::warn_throw_in_noexcept_func) << FD;
324  if (S.getLangOpts().CPlusPlus11 &&
325  (isa<CXXDestructorDecl>(FD) ||
326  FD->getDeclName().getCXXOverloadedOperator() == OO_Delete ||
327  FD->getDeclName().getCXXOverloadedOperator() == OO_Array_Delete)) {
328  if (const auto *Ty = FD->getTypeSourceInfo()->getType()->
329  getAs<FunctionProtoType>())
330  S.Diag(FD->getLocation(), diag::note_throw_in_dtor)
331  << !isa<CXXDestructorDecl>(FD) << !Ty->hasExceptionSpec()
333  } else
334  S.Diag(FD->getLocation(), diag::note_throw_in_function)
336  }
337 }
338 
340  AnalysisDeclContext &AC) {
341  CFG *BodyCFG = AC.getCFG();
342  if (!BodyCFG)
343  return;
344  if (BodyCFG->getExit().pred_empty())
345  return;
346  visitReachableThrows(BodyCFG, [&](const CXXThrowExpr *Throw, CFGBlock &Block) {
347  if (throwEscapes(S, Throw, Block, BodyCFG))
349  });
350 }
351 
352 static bool isNoexcept(const FunctionDecl *FD) {
353  const auto *FPT = FD->getType()->castAs<FunctionProtoType>();
354  if (FPT->isNothrow() || FD->hasAttr<NoThrowAttr>())
355  return true;
356  return false;
357 }
358 
359 //===----------------------------------------------------------------------===//
360 // Check for missing return value.
361 //===----------------------------------------------------------------------===//
362 
369 };
370 
371 /// CheckFallThrough - Check that we don't fall off the end of a
372 /// Statement that should return a value.
373 ///
374 /// \returns AlwaysFallThrough iff we always fall off the end of the statement,
375 /// MaybeFallThrough iff we might or might not fall off the end,
376 /// NeverFallThroughOrReturn iff we never fall off the end of the statement or
377 /// return. We assume NeverFallThrough iff we never fall off the end of the
378 /// statement but we may return. We assume that functions not marked noreturn
379 /// will return.
381  CFG *cfg = AC.getCFG();
382  if (!cfg) return UnknownFallThrough;
383 
384  // The CFG leaves in dead things, and we don't want the dead code paths to
385  // confuse us, so we mark all live things first.
386  llvm::BitVector live(cfg->getNumBlockIDs());
387  unsigned count = reachable_code::ScanReachableFromBlock(&cfg->getEntry(),
388  live);
389 
390  bool AddEHEdges = AC.getAddEHEdges();
391  if (!AddEHEdges && count != cfg->getNumBlockIDs())
392  // When there are things remaining dead, and we didn't add EH edges
393  // from CallExprs to the catch clauses, we have to go back and
394  // mark them as live.
395  for (const auto *B : *cfg) {
396  if (!live[B->getBlockID()]) {
397  if (B->pred_begin() == B->pred_end()) {
398  if (B->getTerminator() && isa<CXXTryStmt>(B->getTerminator()))
399  // When not adding EH edges from calls, catch clauses
400  // can otherwise seem dead. Avoid noting them as dead.
401  count += reachable_code::ScanReachableFromBlock(B, live);
402  continue;
403  }
404  }
405  }
406 
407  // Now we know what is live, we check the live precessors of the exit block
408  // and look for fall through paths, being careful to ignore normal returns,
409  // and exceptional paths.
410  bool HasLiveReturn = false;
411  bool HasFakeEdge = false;
412  bool HasPlainEdge = false;
413  bool HasAbnormalEdge = false;
414 
415  // Ignore default cases that aren't likely to be reachable because all
416  // enums in a switch(X) have explicit case statements.
419 
421  I = cfg->getExit().filtered_pred_start_end(FO); I.hasMore(); ++I) {
422  const CFGBlock& B = **I;
423  if (!live[B.getBlockID()])
424  continue;
425 
426  // Skip blocks which contain an element marked as no-return. They don't
427  // represent actually viable edges into the exit block, so mark them as
428  // abnormal.
429  if (B.hasNoReturnElement()) {
430  HasAbnormalEdge = true;
431  continue;
432  }
433 
434  // Destructors can appear after the 'return' in the CFG. This is
435  // normal. We need to look pass the destructors for the return
436  // statement (if it exists).
437  CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend();
438 
439  for ( ; ri != re ; ++ri)
440  if (ri->getAs<CFGStmt>())
441  break;
442 
443  // No more CFGElements in the block?
444  if (ri == re) {
445  if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) {
446  HasAbnormalEdge = true;
447  continue;
448  }
449  // A labeled empty statement, or the entry block...
450  HasPlainEdge = true;
451  continue;
452  }
453 
454  CFGStmt CS = ri->castAs<CFGStmt>();
455  const Stmt *S = CS.getStmt();
456  if (isa<ReturnStmt>(S) || isa<CoreturnStmt>(S)) {
457  HasLiveReturn = true;
458  continue;
459  }
460  if (isa<ObjCAtThrowStmt>(S)) {
461  HasFakeEdge = true;
462  continue;
463  }
464  if (isa<CXXThrowExpr>(S)) {
465  HasFakeEdge = true;
466  continue;
467  }
468  if (isa<MSAsmStmt>(S)) {
469  // TODO: Verify this is correct.
470  HasFakeEdge = true;
471  HasLiveReturn = true;
472  continue;
473  }
474  if (isa<CXXTryStmt>(S)) {
475  HasAbnormalEdge = true;
476  continue;
477  }
478  if (std::find(B.succ_begin(), B.succ_end(), &cfg->getExit())
479  == B.succ_end()) {
480  HasAbnormalEdge = true;
481  continue;
482  }
483 
484  HasPlainEdge = true;
485  }
486  if (!HasPlainEdge) {
487  if (HasLiveReturn)
488  return NeverFallThrough;
490  }
491  if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
492  return MaybeFallThrough;
493  // This says AlwaysFallThrough for calls to functions that are not marked
494  // noreturn, that don't return. If people would like this warning to be more
495  // accurate, such functions should be marked as noreturn.
496  return AlwaysFallThrough;
497 }
498 
499 namespace {
500 
501 struct CheckFallThroughDiagnostics {
502  unsigned diag_MaybeFallThrough_HasNoReturn;
503  unsigned diag_MaybeFallThrough_ReturnsNonVoid;
504  unsigned diag_AlwaysFallThrough_HasNoReturn;
505  unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
506  unsigned diag_NeverFallThroughOrReturn;
507  enum { Function, Block, Lambda, Coroutine } funMode;
508  SourceLocation FuncLoc;
509 
510  static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
511  CheckFallThroughDiagnostics D;
512  D.FuncLoc = Func->getLocation();
513  D.diag_MaybeFallThrough_HasNoReturn =
514  diag::warn_falloff_noreturn_function;
515  D.diag_MaybeFallThrough_ReturnsNonVoid =
516  diag::warn_maybe_falloff_nonvoid_function;
517  D.diag_AlwaysFallThrough_HasNoReturn =
518  diag::warn_falloff_noreturn_function;
519  D.diag_AlwaysFallThrough_ReturnsNonVoid =
520  diag::warn_falloff_nonvoid_function;
521 
522  // Don't suggest that virtual functions be marked "noreturn", since they
523  // might be overridden by non-noreturn functions.
524  bool isVirtualMethod = false;
525  if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Func))
526  isVirtualMethod = Method->isVirtual();
527 
528  // Don't suggest that template instantiations be marked "noreturn"
529  bool isTemplateInstantiation = false;
530  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Func))
531  isTemplateInstantiation = Function->isTemplateInstantiation();
532 
533  if (!isVirtualMethod && !isTemplateInstantiation)
534  D.diag_NeverFallThroughOrReturn =
535  diag::warn_suggest_noreturn_function;
536  else
537  D.diag_NeverFallThroughOrReturn = 0;
538 
539  D.funMode = Function;
540  return D;
541  }
542 
543  static CheckFallThroughDiagnostics MakeForCoroutine(const Decl *Func) {
544  CheckFallThroughDiagnostics D;
545  D.FuncLoc = Func->getLocation();
546  D.diag_MaybeFallThrough_HasNoReturn = 0;
547  D.diag_MaybeFallThrough_ReturnsNonVoid =
548  diag::warn_maybe_falloff_nonvoid_coroutine;
549  D.diag_AlwaysFallThrough_HasNoReturn = 0;
550  D.diag_AlwaysFallThrough_ReturnsNonVoid =
551  diag::warn_falloff_nonvoid_coroutine;
552  D.funMode = Coroutine;
553  return D;
554  }
555 
556  static CheckFallThroughDiagnostics MakeForBlock() {
557  CheckFallThroughDiagnostics D;
558  D.diag_MaybeFallThrough_HasNoReturn =
559  diag::err_noreturn_block_has_return_expr;
560  D.diag_MaybeFallThrough_ReturnsNonVoid =
561  diag::err_maybe_falloff_nonvoid_block;
562  D.diag_AlwaysFallThrough_HasNoReturn =
563  diag::err_noreturn_block_has_return_expr;
564  D.diag_AlwaysFallThrough_ReturnsNonVoid =
565  diag::err_falloff_nonvoid_block;
566  D.diag_NeverFallThroughOrReturn = 0;
567  D.funMode = Block;
568  return D;
569  }
570 
571  static CheckFallThroughDiagnostics MakeForLambda() {
572  CheckFallThroughDiagnostics D;
573  D.diag_MaybeFallThrough_HasNoReturn =
574  diag::err_noreturn_lambda_has_return_expr;
575  D.diag_MaybeFallThrough_ReturnsNonVoid =
576  diag::warn_maybe_falloff_nonvoid_lambda;
577  D.diag_AlwaysFallThrough_HasNoReturn =
578  diag::err_noreturn_lambda_has_return_expr;
579  D.diag_AlwaysFallThrough_ReturnsNonVoid =
580  diag::warn_falloff_nonvoid_lambda;
581  D.diag_NeverFallThroughOrReturn = 0;
582  D.funMode = Lambda;
583  return D;
584  }
585 
586  bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
587  bool HasNoReturn) const {
588  if (funMode == Function) {
589  return (ReturnsVoid ||
590  D.isIgnored(diag::warn_maybe_falloff_nonvoid_function,
591  FuncLoc)) &&
592  (!HasNoReturn ||
593  D.isIgnored(diag::warn_noreturn_function_has_return_expr,
594  FuncLoc)) &&
595  (!ReturnsVoid ||
596  D.isIgnored(diag::warn_suggest_noreturn_block, FuncLoc));
597  }
598  if (funMode == Coroutine) {
599  return (ReturnsVoid ||
600  D.isIgnored(diag::warn_maybe_falloff_nonvoid_function, FuncLoc) ||
601  D.isIgnored(diag::warn_maybe_falloff_nonvoid_coroutine,
602  FuncLoc)) &&
603  (!HasNoReturn);
604  }
605  // For blocks / lambdas.
606  return ReturnsVoid && !HasNoReturn;
607  }
608 };
609 
610 } // anonymous namespace
611 
612 /// CheckFallThroughForBody - Check that we don't fall off the end of a
613 /// function that should return a value. Check that we don't fall off the end
614 /// of a noreturn function. We assume that functions and blocks not marked
615 /// noreturn will return.
616 static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
617  const BlockExpr *blkExpr,
618  const CheckFallThroughDiagnostics &CD,
621 
622  bool ReturnsVoid = false;
623  bool HasNoReturn = false;
624  bool IsCoroutine = FSI->isCoroutine();
625 
626  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
627  if (const auto *CBody = dyn_cast<CoroutineBodyStmt>(Body))
628  ReturnsVoid = CBody->getFallthroughHandler() != nullptr;
629  else
630  ReturnsVoid = FD->getReturnType()->isVoidType();
631  HasNoReturn = FD->isNoReturn();
632  }
633  else if (const auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
634  ReturnsVoid = MD->getReturnType()->isVoidType();
635  HasNoReturn = MD->hasAttr<NoReturnAttr>();
636  }
637  else if (isa<BlockDecl>(D)) {
638  QualType BlockTy = blkExpr->getType();
639  if (const FunctionType *FT =
640  BlockTy->getPointeeType()->getAs<FunctionType>()) {
641  if (FT->getReturnType()->isVoidType())
642  ReturnsVoid = true;
643  if (FT->getNoReturnAttr())
644  HasNoReturn = true;
645  }
646  }
647 
648  DiagnosticsEngine &Diags = S.getDiagnostics();
649 
650  // Short circuit for compilation speed.
651  if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn))
652  return;
653  SourceLocation LBrace = Body->getLocStart(), RBrace = Body->getLocEnd();
654  auto EmitDiag = [&](SourceLocation Loc, unsigned DiagID) {
655  if (IsCoroutine)
656  S.Diag(Loc, DiagID) << FSI->CoroutinePromise->getType();
657  else
658  S.Diag(Loc, DiagID);
659  };
660  // Either in a function body compound statement, or a function-try-block.
661  switch (CheckFallThrough(AC)) {
662  case UnknownFallThrough:
663  break;
664 
665  case MaybeFallThrough:
666  if (HasNoReturn)
667  EmitDiag(RBrace, CD.diag_MaybeFallThrough_HasNoReturn);
668  else if (!ReturnsVoid)
669  EmitDiag(RBrace, CD.diag_MaybeFallThrough_ReturnsNonVoid);
670  break;
671  case AlwaysFallThrough:
672  if (HasNoReturn)
673  EmitDiag(RBrace, CD.diag_AlwaysFallThrough_HasNoReturn);
674  else if (!ReturnsVoid)
675  EmitDiag(RBrace, CD.diag_AlwaysFallThrough_ReturnsNonVoid);
676  break;
678  if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
679  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
680  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 0 << FD;
681  } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
682  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 1 << MD;
683  } else {
684  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn);
685  }
686  }
687  break;
688  case NeverFallThrough:
689  break;
690  }
691 }
692 
693 //===----------------------------------------------------------------------===//
694 // -Wuninitialized
695 //===----------------------------------------------------------------------===//
696 
697 namespace {
698 /// ContainsReference - A visitor class to search for references to
699 /// a particular declaration (the needle) within any evaluated component of an
700 /// expression (recursively).
701 class ContainsReference : public ConstEvaluatedExprVisitor<ContainsReference> {
702  bool FoundReference;
703  const DeclRefExpr *Needle;
704 
705 public:
707 
708  ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
709  : Inherited(Context), FoundReference(false), Needle(Needle) {}
710 
711  void VisitExpr(const Expr *E) {
712  // Stop evaluating if we already have a reference.
713  if (FoundReference)
714  return;
715 
716  Inherited::VisitExpr(E);
717  }
718 
719  void VisitDeclRefExpr(const DeclRefExpr *E) {
720  if (E == Needle)
721  FoundReference = true;
722  else
723  Inherited::VisitDeclRefExpr(E);
724  }
725 
726  bool doesContainReference() const { return FoundReference; }
727 };
728 } // anonymous namespace
729 
730 static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
731  QualType VariableTy = VD->getType().getCanonicalType();
732  if (VariableTy->isBlockPointerType() &&
733  !VD->hasAttr<BlocksAttr>()) {
734  S.Diag(VD->getLocation(), diag::note_block_var_fixit_add_initialization)
735  << VD->getDeclName()
736  << FixItHint::CreateInsertion(VD->getLocation(), "__block ");
737  return true;
738  }
739 
740  // Don't issue a fixit if there is already an initializer.
741  if (VD->getInit())
742  return false;
743 
744  // Don't suggest a fixit inside macros.
745  if (VD->getLocEnd().isMacroID())
746  return false;
747 
749 
750  // Suggest possible initialization (if any).
751  std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
752  if (Init.empty())
753  return false;
754 
755  S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName()
756  << FixItHint::CreateInsertion(Loc, Init);
757  return true;
758 }
759 
760 /// Create a fixit to remove an if-like statement, on the assumption that its
761 /// condition is CondVal.
762 static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then,
763  const Stmt *Else, bool CondVal,
764  FixItHint &Fixit1, FixItHint &Fixit2) {
765  if (CondVal) {
766  // If condition is always true, remove all but the 'then'.
767  Fixit1 = FixItHint::CreateRemoval(
769  Then->getLocStart()));
770  if (Else) {
771  SourceLocation ElseKwLoc = S.getLocForEndOfToken(Then->getLocEnd());
772  Fixit2 = FixItHint::CreateRemoval(
773  SourceRange(ElseKwLoc, Else->getLocEnd()));
774  }
775  } else {
776  // If condition is always false, remove all but the 'else'.
777  if (Else)
778  Fixit1 = FixItHint::CreateRemoval(
780  Else->getLocStart()));
781  else
783  }
784 }
785 
786 /// DiagUninitUse -- Helper function to produce a diagnostic for an
787 /// uninitialized use of a variable.
788 static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
789  bool IsCapturedByBlock) {
790  bool Diagnosed = false;
791 
792  switch (Use.getKind()) {
793  case UninitUse::Always:
794  S.Diag(Use.getUser()->getLocStart(), diag::warn_uninit_var)
795  << VD->getDeclName() << IsCapturedByBlock
796  << Use.getUser()->getSourceRange();
797  return;
798 
801  S.Diag(VD->getLocation(), diag::warn_sometimes_uninit_var)
802  << VD->getDeclName() << IsCapturedByBlock
803  << (Use.getKind() == UninitUse::AfterDecl ? 4 : 5)
804  << const_cast<DeclContext*>(VD->getLexicalDeclContext())
805  << VD->getSourceRange();
806  S.Diag(Use.getUser()->getLocStart(), diag::note_uninit_var_use)
807  << IsCapturedByBlock << Use.getUser()->getSourceRange();
808  return;
809 
810  case UninitUse::Maybe:
812  // Carry on to report sometimes-uninitialized branches, if possible,
813  // or a 'may be used uninitialized' diagnostic otherwise.
814  break;
815  }
816 
817  // Diagnose each branch which leads to a sometimes-uninitialized use.
818  for (UninitUse::branch_iterator I = Use.branch_begin(), E = Use.branch_end();
819  I != E; ++I) {
820  assert(Use.getKind() == UninitUse::Sometimes);
821 
822  const Expr *User = Use.getUser();
823  const Stmt *Term = I->Terminator;
824 
825  // Information used when building the diagnostic.
826  unsigned DiagKind;
827  StringRef Str;
828  SourceRange Range;
829 
830  // FixIts to suppress the diagnostic by removing the dead condition.
831  // For all binary terminators, branch 0 is taken if the condition is true,
832  // and branch 1 is taken if the condition is false.
833  int RemoveDiagKind = -1;
834  const char *FixitStr =
835  S.getLangOpts().CPlusPlus ? (I->Output ? "true" : "false")
836  : (I->Output ? "1" : "0");
837  FixItHint Fixit1, Fixit2;
838 
839  switch (Term ? Term->getStmtClass() : Stmt::DeclStmtClass) {
840  default:
841  // Don't know how to report this. Just fall back to 'may be used
842  // uninitialized'. FIXME: Can this happen?
843  continue;
844 
845  // "condition is true / condition is false".
846  case Stmt::IfStmtClass: {
847  const IfStmt *IS = cast<IfStmt>(Term);
848  DiagKind = 0;
849  Str = "if";
850  Range = IS->getCond()->getSourceRange();
851  RemoveDiagKind = 0;
852  CreateIfFixit(S, IS, IS->getThen(), IS->getElse(),
853  I->Output, Fixit1, Fixit2);
854  break;
855  }
856  case Stmt::ConditionalOperatorClass: {
857  const ConditionalOperator *CO = cast<ConditionalOperator>(Term);
858  DiagKind = 0;
859  Str = "?:";
860  Range = CO->getCond()->getSourceRange();
861  RemoveDiagKind = 0;
862  CreateIfFixit(S, CO, CO->getTrueExpr(), CO->getFalseExpr(),
863  I->Output, Fixit1, Fixit2);
864  break;
865  }
866  case Stmt::BinaryOperatorClass: {
867  const BinaryOperator *BO = cast<BinaryOperator>(Term);
868  if (!BO->isLogicalOp())
869  continue;
870  DiagKind = 0;
871  Str = BO->getOpcodeStr();
872  Range = BO->getLHS()->getSourceRange();
873  RemoveDiagKind = 0;
874  if ((BO->getOpcode() == BO_LAnd && I->Output) ||
875  (BO->getOpcode() == BO_LOr && !I->Output))
876  // true && y -> y, false || y -> y.
878  BO->getOperatorLoc()));
879  else
880  // false && y -> false, true || y -> true.
881  Fixit1 = FixItHint::CreateReplacement(BO->getSourceRange(), FixitStr);
882  break;
883  }
884 
885  // "loop is entered / loop is exited".
886  case Stmt::WhileStmtClass:
887  DiagKind = 1;
888  Str = "while";
889  Range = cast<WhileStmt>(Term)->getCond()->getSourceRange();
890  RemoveDiagKind = 1;
891  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
892  break;
893  case Stmt::ForStmtClass:
894  DiagKind = 1;
895  Str = "for";
896  Range = cast<ForStmt>(Term)->getCond()->getSourceRange();
897  RemoveDiagKind = 1;
898  if (I->Output)
899  Fixit1 = FixItHint::CreateRemoval(Range);
900  else
901  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
902  break;
903  case Stmt::CXXForRangeStmtClass:
904  if (I->Output == 1) {
905  // The use occurs if a range-based for loop's body never executes.
906  // That may be impossible, and there's no syntactic fix for this,
907  // so treat it as a 'may be uninitialized' case.
908  continue;
909  }
910  DiagKind = 1;
911  Str = "for";
912  Range = cast<CXXForRangeStmt>(Term)->getRangeInit()->getSourceRange();
913  break;
914 
915  // "condition is true / loop is exited".
916  case Stmt::DoStmtClass:
917  DiagKind = 2;
918  Str = "do";
919  Range = cast<DoStmt>(Term)->getCond()->getSourceRange();
920  RemoveDiagKind = 1;
921  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
922  break;
923 
924  // "switch case is taken".
925  case Stmt::CaseStmtClass:
926  DiagKind = 3;
927  Str = "case";
928  Range = cast<CaseStmt>(Term)->getLHS()->getSourceRange();
929  break;
930  case Stmt::DefaultStmtClass:
931  DiagKind = 3;
932  Str = "default";
933  Range = cast<DefaultStmt>(Term)->getDefaultLoc();
934  break;
935  }
936 
937  S.Diag(Range.getBegin(), diag::warn_sometimes_uninit_var)
938  << VD->getDeclName() << IsCapturedByBlock << DiagKind
939  << Str << I->Output << Range;
940  S.Diag(User->getLocStart(), diag::note_uninit_var_use)
941  << IsCapturedByBlock << User->getSourceRange();
942  if (RemoveDiagKind != -1)
943  S.Diag(Fixit1.RemoveRange.getBegin(), diag::note_uninit_fixit_remove_cond)
944  << RemoveDiagKind << Str << I->Output << Fixit1 << Fixit2;
945 
946  Diagnosed = true;
947  }
948 
949  if (!Diagnosed)
950  S.Diag(Use.getUser()->getLocStart(), diag::warn_maybe_uninit_var)
951  << VD->getDeclName() << IsCapturedByBlock
952  << Use.getUser()->getSourceRange();
953 }
954 
955 /// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
956 /// uninitialized variable. This manages the different forms of diagnostic
957 /// emitted for particular types of uses. Returns true if the use was diagnosed
958 /// as a warning. If a particular use is one we omit warnings for, returns
959 /// false.
960 static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
961  const UninitUse &Use,
962  bool alwaysReportSelfInit = false) {
963  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Use.getUser())) {
964  // Inspect the initializer of the variable declaration which is
965  // being referenced prior to its initialization. We emit
966  // specialized diagnostics for self-initialization, and we
967  // specifically avoid warning about self references which take the
968  // form of:
969  //
970  // int x = x;
971  //
972  // This is used to indicate to GCC that 'x' is intentionally left
973  // uninitialized. Proven code paths which access 'x' in
974  // an uninitialized state after this will still warn.
975  if (const Expr *Initializer = VD->getInit()) {
976  if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
977  return false;
978 
979  ContainsReference CR(S.Context, DRE);
980  CR.Visit(Initializer);
981  if (CR.doesContainReference()) {
982  S.Diag(DRE->getLocStart(),
983  diag::warn_uninit_self_reference_in_init)
984  << VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
985  return true;
986  }
987  }
988 
989  DiagUninitUse(S, VD, Use, false);
990  } else {
991  const BlockExpr *BE = cast<BlockExpr>(Use.getUser());
992  if (VD->getType()->isBlockPointerType() && !VD->hasAttr<BlocksAttr>())
993  S.Diag(BE->getLocStart(),
994  diag::warn_uninit_byref_blockvar_captured_by_block)
995  << VD->getDeclName();
996  else
997  DiagUninitUse(S, VD, Use, true);
998  }
999 
1000  // Report where the variable was declared when the use wasn't within
1001  // the initializer of that declaration & we didn't already suggest
1002  // an initialization fixit.
1003  if (!SuggestInitializationFixit(S, VD))
1004  S.Diag(VD->getLocStart(), diag::note_var_declared_here)
1005  << VD->getDeclName();
1006 
1007  return true;
1008 }
1009 
1010 namespace {
1011  class FallthroughMapper : public RecursiveASTVisitor<FallthroughMapper> {
1012  public:
1013  FallthroughMapper(Sema &S)
1014  : FoundSwitchStatements(false),
1015  S(S) {
1016  }
1017 
1018  bool foundSwitchStatements() const { return FoundSwitchStatements; }
1019 
1020  void markFallthroughVisited(const AttributedStmt *Stmt) {
1021  bool Found = FallthroughStmts.erase(Stmt);
1022  assert(Found);
1023  (void)Found;
1024  }
1025 
1026  typedef llvm::SmallPtrSet<const AttributedStmt*, 8> AttrStmts;
1027 
1028  const AttrStmts &getFallthroughStmts() const {
1029  return FallthroughStmts;
1030  }
1031 
1032  void fillReachableBlocks(CFG *Cfg) {
1033  assert(ReachableBlocks.empty() && "ReachableBlocks already filled");
1034  std::deque<const CFGBlock *> BlockQueue;
1035 
1036  ReachableBlocks.insert(&Cfg->getEntry());
1037  BlockQueue.push_back(&Cfg->getEntry());
1038  // Mark all case blocks reachable to avoid problems with switching on
1039  // constants, covered enums, etc.
1040  // These blocks can contain fall-through annotations, and we don't want to
1041  // issue a warn_fallthrough_attr_unreachable for them.
1042  for (const auto *B : *Cfg) {
1043  const Stmt *L = B->getLabel();
1044  if (L && isa<SwitchCase>(L) && ReachableBlocks.insert(B).second)
1045  BlockQueue.push_back(B);
1046  }
1047 
1048  while (!BlockQueue.empty()) {
1049  const CFGBlock *P = BlockQueue.front();
1050  BlockQueue.pop_front();
1052  E = P->succ_end();
1053  I != E; ++I) {
1054  if (*I && ReachableBlocks.insert(*I).second)
1055  BlockQueue.push_back(*I);
1056  }
1057  }
1058  }
1059 
1060  bool checkFallThroughIntoBlock(const CFGBlock &B, int &AnnotatedCnt,
1061  bool IsTemplateInstantiation) {
1062  assert(!ReachableBlocks.empty() && "ReachableBlocks empty");
1063 
1064  int UnannotatedCnt = 0;
1065  AnnotatedCnt = 0;
1066 
1067  std::deque<const CFGBlock*> BlockQueue(B.pred_begin(), B.pred_end());
1068  while (!BlockQueue.empty()) {
1069  const CFGBlock *P = BlockQueue.front();
1070  BlockQueue.pop_front();
1071  if (!P) continue;
1072 
1073  const Stmt *Term = P->getTerminator();
1074  if (Term && isa<SwitchStmt>(Term))
1075  continue; // Switch statement, good.
1076 
1077  const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(P->getLabel());
1078  if (SW && SW->getSubStmt() == B.getLabel() && P->begin() == P->end())
1079  continue; // Previous case label has no statements, good.
1080 
1081  const LabelStmt *L = dyn_cast_or_null<LabelStmt>(P->getLabel());
1082  if (L && L->getSubStmt() == B.getLabel() && P->begin() == P->end())
1083  continue; // Case label is preceded with a normal label, good.
1084 
1085  if (!ReachableBlocks.count(P)) {
1086  for (CFGBlock::const_reverse_iterator ElemIt = P->rbegin(),
1087  ElemEnd = P->rend();
1088  ElemIt != ElemEnd; ++ElemIt) {
1089  if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>()) {
1090  if (const AttributedStmt *AS = asFallThroughAttr(CS->getStmt())) {
1091  // Don't issue a warning for an unreachable fallthrough
1092  // attribute in template instantiations as it may not be
1093  // unreachable in all instantiations of the template.
1094  if (!IsTemplateInstantiation)
1095  S.Diag(AS->getLocStart(),
1096  diag::warn_fallthrough_attr_unreachable);
1097  markFallthroughVisited(AS);
1098  ++AnnotatedCnt;
1099  break;
1100  }
1101  // Don't care about other unreachable statements.
1102  }
1103  }
1104  // If there are no unreachable statements, this may be a special
1105  // case in CFG:
1106  // case X: {
1107  // A a; // A has a destructor.
1108  // break;
1109  // }
1110  // // <<<< This place is represented by a 'hanging' CFG block.
1111  // case Y:
1112  continue;
1113  }
1114 
1115  const Stmt *LastStmt = getLastStmt(*P);
1116  if (const AttributedStmt *AS = asFallThroughAttr(LastStmt)) {
1117  markFallthroughVisited(AS);
1118  ++AnnotatedCnt;
1119  continue; // Fallthrough annotation, good.
1120  }
1121 
1122  if (!LastStmt) { // This block contains no executable statements.
1123  // Traverse its predecessors.
1124  std::copy(P->pred_begin(), P->pred_end(),
1125  std::back_inserter(BlockQueue));
1126  continue;
1127  }
1128 
1129  ++UnannotatedCnt;
1130  }
1131  return !!UnannotatedCnt;
1132  }
1133 
1134  // RecursiveASTVisitor setup.
1135  bool shouldWalkTypesOfTypeLocs() const { return false; }
1136 
1137  bool VisitAttributedStmt(AttributedStmt *S) {
1138  if (asFallThroughAttr(S))
1139  FallthroughStmts.insert(S);
1140  return true;
1141  }
1142 
1143  bool VisitSwitchStmt(SwitchStmt *S) {
1144  FoundSwitchStatements = true;
1145  return true;
1146  }
1147 
1148  // We don't want to traverse local type declarations. We analyze their
1149  // methods separately.
1150  bool TraverseDecl(Decl *D) { return true; }
1151 
1152  // We analyze lambda bodies separately. Skip them here.
1153  bool TraverseLambdaBody(LambdaExpr *LE) { return true; }
1154 
1155  private:
1156 
1157  static const AttributedStmt *asFallThroughAttr(const Stmt *S) {
1158  if (const AttributedStmt *AS = dyn_cast_or_null<AttributedStmt>(S)) {
1159  if (hasSpecificAttr<FallThroughAttr>(AS->getAttrs()))
1160  return AS;
1161  }
1162  return nullptr;
1163  }
1164 
1165  static const Stmt *getLastStmt(const CFGBlock &B) {
1166  if (const Stmt *Term = B.getTerminator())
1167  return Term;
1168  for (CFGBlock::const_reverse_iterator ElemIt = B.rbegin(),
1169  ElemEnd = B.rend();
1170  ElemIt != ElemEnd; ++ElemIt) {
1171  if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>())
1172  return CS->getStmt();
1173  }
1174  // Workaround to detect a statement thrown out by CFGBuilder:
1175  // case X: {} case Y:
1176  // case X: ; case Y:
1177  if (const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(B.getLabel()))
1178  if (!isa<SwitchCase>(SW->getSubStmt()))
1179  return SW->getSubStmt();
1180 
1181  return nullptr;
1182  }
1183 
1184  bool FoundSwitchStatements;
1185  AttrStmts FallthroughStmts;
1186  Sema &S;
1187  llvm::SmallPtrSet<const CFGBlock *, 16> ReachableBlocks;
1188  };
1189 } // anonymous namespace
1190 
1192  SourceLocation Loc) {
1193  TokenValue FallthroughTokens[] = {
1194  tok::l_square, tok::l_square,
1195  PP.getIdentifierInfo("fallthrough"),
1196  tok::r_square, tok::r_square
1197  };
1198 
1199  TokenValue ClangFallthroughTokens[] = {
1200  tok::l_square, tok::l_square, PP.getIdentifierInfo("clang"),
1201  tok::coloncolon, PP.getIdentifierInfo("fallthrough"),
1202  tok::r_square, tok::r_square
1203  };
1204 
1205  bool PreferClangAttr = !PP.getLangOpts().CPlusPlus17;
1206 
1207  StringRef MacroName;
1208  if (PreferClangAttr)
1209  MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
1210  if (MacroName.empty())
1211  MacroName = PP.getLastMacroWithSpelling(Loc, FallthroughTokens);
1212  if (MacroName.empty() && !PreferClangAttr)
1213  MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
1214  if (MacroName.empty())
1215  MacroName = PreferClangAttr ? "[[clang::fallthrough]]" : "[[fallthrough]]";
1216  return MacroName;
1217 }
1218 
1220  bool PerFunction) {
1221  // Only perform this analysis when using [[]] attributes. There is no good
1222  // workflow for this warning when not using C++11. There is no good way to
1223  // silence the warning (no attribute is available) unless we are using
1224  // [[]] attributes. One could use pragmas to silence the warning, but as a
1225  // general solution that is gross and not in the spirit of this warning.
1226  //
1227  // NOTE: This an intermediate solution. There are on-going discussions on
1228  // how to properly support this warning outside of C++11 with an annotation.
1229  if (!AC.getASTContext().getLangOpts().DoubleSquareBracketAttributes)
1230  return;
1231 
1232  FallthroughMapper FM(S);
1233  FM.TraverseStmt(AC.getBody());
1234 
1235  if (!FM.foundSwitchStatements())
1236  return;
1237 
1238  if (PerFunction && FM.getFallthroughStmts().empty())
1239  return;
1240 
1241  CFG *Cfg = AC.getCFG();
1242 
1243  if (!Cfg)
1244  return;
1245 
1246  FM.fillReachableBlocks(Cfg);
1247 
1248  for (const CFGBlock *B : llvm::reverse(*Cfg)) {
1249  const Stmt *Label = B->getLabel();
1250 
1251  if (!Label || !isa<SwitchCase>(Label))
1252  continue;
1253 
1254  int AnnotatedCnt;
1255 
1256  bool IsTemplateInstantiation = false;
1257  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(AC.getDecl()))
1258  IsTemplateInstantiation = Function->isTemplateInstantiation();
1259  if (!FM.checkFallThroughIntoBlock(*B, AnnotatedCnt,
1260  IsTemplateInstantiation))
1261  continue;
1262 
1263  S.Diag(Label->getLocStart(),
1264  PerFunction ? diag::warn_unannotated_fallthrough_per_function
1265  : diag::warn_unannotated_fallthrough);
1266 
1267  if (!AnnotatedCnt) {
1268  SourceLocation L = Label->getLocStart();
1269  if (L.isMacroID())
1270  continue;
1271  if (S.getLangOpts().CPlusPlus11) {
1272  const Stmt *Term = B->getTerminator();
1273  // Skip empty cases.
1274  while (B->empty() && !Term && B->succ_size() == 1) {
1275  B = *B->succ_begin();
1276  Term = B->getTerminator();
1277  }
1278  if (!(B->empty() && Term && isa<BreakStmt>(Term))) {
1279  Preprocessor &PP = S.getPreprocessor();
1280  StringRef AnnotationSpelling = getFallthroughAttrSpelling(PP, L);
1281  SmallString<64> TextToInsert(AnnotationSpelling);
1282  TextToInsert += "; ";
1283  S.Diag(L, diag::note_insert_fallthrough_fixit) <<
1284  AnnotationSpelling <<
1285  FixItHint::CreateInsertion(L, TextToInsert);
1286  }
1287  }
1288  S.Diag(L, diag::note_insert_break_fixit) <<
1289  FixItHint::CreateInsertion(L, "break; ");
1290  }
1291  }
1292 
1293  for (const auto *F : FM.getFallthroughStmts())
1294  S.Diag(F->getLocStart(), diag::err_fallthrough_attr_invalid_placement);
1295 }
1296 
1297 static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM,
1298  const Stmt *S) {
1299  assert(S);
1300 
1301  do {
1302  switch (S->getStmtClass()) {
1303  case Stmt::ForStmtClass:
1304  case Stmt::WhileStmtClass:
1305  case Stmt::CXXForRangeStmtClass:
1306  case Stmt::ObjCForCollectionStmtClass:
1307  return true;
1308  case Stmt::DoStmtClass: {
1309  const Expr *Cond = cast<DoStmt>(S)->getCond();
1310  llvm::APSInt Val;
1311  if (!Cond->EvaluateAsInt(Val, Ctx))
1312  return true;
1313  return Val.getBoolValue();
1314  }
1315  default:
1316  break;
1317  }
1318  } while ((S = PM.getParent(S)));
1319 
1320  return false;
1321 }
1322 
1324  const sema::FunctionScopeInfo *CurFn,
1325  const Decl *D,
1326  const ParentMap &PM) {
1327  typedef sema::FunctionScopeInfo::WeakObjectProfileTy WeakObjectProfileTy;
1328  typedef sema::FunctionScopeInfo::WeakObjectUseMap WeakObjectUseMap;
1329  typedef sema::FunctionScopeInfo::WeakUseVector WeakUseVector;
1330  typedef std::pair<const Stmt *, WeakObjectUseMap::const_iterator>
1331  StmtUsesPair;
1332 
1333  ASTContext &Ctx = S.getASTContext();
1334 
1335  const WeakObjectUseMap &WeakMap = CurFn->getWeakObjectUses();
1336 
1337  // Extract all weak objects that are referenced more than once.
1338  SmallVector<StmtUsesPair, 8> UsesByStmt;
1339  for (WeakObjectUseMap::const_iterator I = WeakMap.begin(), E = WeakMap.end();
1340  I != E; ++I) {
1341  const WeakUseVector &Uses = I->second;
1342 
1343  // Find the first read of the weak object.
1344  WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
1345  for ( ; UI != UE; ++UI) {
1346  if (UI->isUnsafe())
1347  break;
1348  }
1349 
1350  // If there were only writes to this object, don't warn.
1351  if (UI == UE)
1352  continue;
1353 
1354  // If there was only one read, followed by any number of writes, and the
1355  // read is not within a loop, don't warn. Additionally, don't warn in a
1356  // loop if the base object is a local variable -- local variables are often
1357  // changed in loops.
1358  if (UI == Uses.begin()) {
1359  WeakUseVector::const_iterator UI2 = UI;
1360  for (++UI2; UI2 != UE; ++UI2)
1361  if (UI2->isUnsafe())
1362  break;
1363 
1364  if (UI2 == UE) {
1365  if (!isInLoop(Ctx, PM, UI->getUseExpr()))
1366  continue;
1367 
1368  const WeakObjectProfileTy &Profile = I->first;
1369  if (!Profile.isExactProfile())
1370  continue;
1371 
1372  const NamedDecl *Base = Profile.getBase();
1373  if (!Base)
1374  Base = Profile.getProperty();
1375  assert(Base && "A profile always has a base or property.");
1376 
1377  if (const VarDecl *BaseVar = dyn_cast<VarDecl>(Base))
1378  if (BaseVar->hasLocalStorage() && !isa<ParmVarDecl>(Base))
1379  continue;
1380  }
1381  }
1382 
1383  UsesByStmt.push_back(StmtUsesPair(UI->getUseExpr(), I));
1384  }
1385 
1386  if (UsesByStmt.empty())
1387  return;
1388 
1389  // Sort by first use so that we emit the warnings in a deterministic order.
1391  llvm::sort(UsesByStmt.begin(), UsesByStmt.end(),
1392  [&SM](const StmtUsesPair &LHS, const StmtUsesPair &RHS) {
1393  return SM.isBeforeInTranslationUnit(LHS.first->getLocStart(),
1394  RHS.first->getLocStart());
1395  });
1396 
1397  // Classify the current code body for better warning text.
1398  // This enum should stay in sync with the cases in
1399  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1400  // FIXME: Should we use a common classification enum and the same set of
1401  // possibilities all throughout Sema?
1402  enum {
1403  Function,
1404  Method,
1405  Block,
1406  Lambda
1407  } FunctionKind;
1408 
1409  if (isa<sema::BlockScopeInfo>(CurFn))
1410  FunctionKind = Block;
1411  else if (isa<sema::LambdaScopeInfo>(CurFn))
1412  FunctionKind = Lambda;
1413  else if (isa<ObjCMethodDecl>(D))
1414  FunctionKind = Method;
1415  else
1416  FunctionKind = Function;
1417 
1418  // Iterate through the sorted problems and emit warnings for each.
1419  for (const auto &P : UsesByStmt) {
1420  const Stmt *FirstRead = P.first;
1421  const WeakObjectProfileTy &Key = P.second->first;
1422  const WeakUseVector &Uses = P.second->second;
1423 
1424  // For complicated expressions like 'a.b.c' and 'x.b.c', WeakObjectProfileTy
1425  // may not contain enough information to determine that these are different
1426  // properties. We can only be 100% sure of a repeated use in certain cases,
1427  // and we adjust the diagnostic kind accordingly so that the less certain
1428  // case can be turned off if it is too noisy.
1429  unsigned DiagKind;
1430  if (Key.isExactProfile())
1431  DiagKind = diag::warn_arc_repeated_use_of_weak;
1432  else
1433  DiagKind = diag::warn_arc_possible_repeated_use_of_weak;
1434 
1435  // Classify the weak object being accessed for better warning text.
1436  // This enum should stay in sync with the cases in
1437  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1438  enum {
1439  Variable,
1440  Property,
1441  ImplicitProperty,
1442  Ivar
1443  } ObjectKind;
1444 
1445  const NamedDecl *KeyProp = Key.getProperty();
1446  if (isa<VarDecl>(KeyProp))
1447  ObjectKind = Variable;
1448  else if (isa<ObjCPropertyDecl>(KeyProp))
1449  ObjectKind = Property;
1450  else if (isa<ObjCMethodDecl>(KeyProp))
1451  ObjectKind = ImplicitProperty;
1452  else if (isa<ObjCIvarDecl>(KeyProp))
1453  ObjectKind = Ivar;
1454  else
1455  llvm_unreachable("Unexpected weak object kind!");
1456 
1457  // Do not warn about IBOutlet weak property receivers being set to null
1458  // since they are typically only used from the main thread.
1459  if (const ObjCPropertyDecl *Prop = dyn_cast<ObjCPropertyDecl>(KeyProp))
1460  if (Prop->hasAttr<IBOutletAttr>())
1461  continue;
1462 
1463  // Show the first time the object was read.
1464  S.Diag(FirstRead->getLocStart(), DiagKind)
1465  << int(ObjectKind) << KeyProp << int(FunctionKind)
1466  << FirstRead->getSourceRange();
1467 
1468  // Print all the other accesses as notes.
1469  for (const auto &Use : Uses) {
1470  if (Use.getUseExpr() == FirstRead)
1471  continue;
1472  S.Diag(Use.getUseExpr()->getLocStart(),
1473  diag::note_arc_weak_also_accessed_here)
1474  << Use.getUseExpr()->getSourceRange();
1475  }
1476  }
1477 }
1478 
1479 namespace {
1480 class UninitValsDiagReporter : public UninitVariablesHandler {
1481  Sema &S;
1482  typedef SmallVector<UninitUse, 2> UsesVec;
1483  typedef llvm::PointerIntPair<UsesVec *, 1, bool> MappedType;
1484  // Prefer using MapVector to DenseMap, so that iteration order will be
1485  // the same as insertion order. This is needed to obtain a deterministic
1486  // order of diagnostics when calling flushDiagnostics().
1487  typedef llvm::MapVector<const VarDecl *, MappedType> UsesMap;
1488  UsesMap uses;
1489 
1490 public:
1491  UninitValsDiagReporter(Sema &S) : S(S) {}
1492  ~UninitValsDiagReporter() override { flushDiagnostics(); }
1493 
1494  MappedType &getUses(const VarDecl *vd) {
1495  MappedType &V = uses[vd];
1496  if (!V.getPointer())
1497  V.setPointer(new UsesVec());
1498  return V;
1499  }
1500 
1501  void handleUseOfUninitVariable(const VarDecl *vd,
1502  const UninitUse &use) override {
1503  getUses(vd).getPointer()->push_back(use);
1504  }
1505 
1506  void handleSelfInit(const VarDecl *vd) override {
1507  getUses(vd).setInt(true);
1508  }
1509 
1510  void flushDiagnostics() {
1511  for (const auto &P : uses) {
1512  const VarDecl *vd = P.first;
1513  const MappedType &V = P.second;
1514 
1515  UsesVec *vec = V.getPointer();
1516  bool hasSelfInit = V.getInt();
1517 
1518  // Specially handle the case where we have uses of an uninitialized
1519  // variable, but the root cause is an idiomatic self-init. We want
1520  // to report the diagnostic at the self-init since that is the root cause.
1521  if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
1524  /* isAlwaysUninit */ true),
1525  /* alwaysReportSelfInit */ true);
1526  else {
1527  // Sort the uses by their SourceLocations. While not strictly
1528  // guaranteed to produce them in line/column order, this will provide
1529  // a stable ordering.
1530  llvm::sort(vec->begin(), vec->end(),
1531  [](const UninitUse &a, const UninitUse &b) {
1532  // Prefer a more confident report over a less confident one.
1533  if (a.getKind() != b.getKind())
1534  return a.getKind() > b.getKind();
1535  return a.getUser()->getLocStart() < b.getUser()->getLocStart();
1536  });
1537 
1538  for (const auto &U : *vec) {
1539  // If we have self-init, downgrade all uses to 'may be uninitialized'.
1540  UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
1541 
1542  if (DiagnoseUninitializedUse(S, vd, Use))
1543  // Skip further diagnostics for this variable. We try to warn only
1544  // on the first point at which a variable is used uninitialized.
1545  break;
1546  }
1547  }
1548 
1549  // Release the uses vector.
1550  delete vec;
1551  }
1552 
1553  uses.clear();
1554  }
1555 
1556 private:
1557  static bool hasAlwaysUninitializedUse(const UsesVec* vec) {
1558  return std::any_of(vec->begin(), vec->end(), [](const UninitUse &U) {
1559  return U.getKind() == UninitUse::Always ||
1560  U.getKind() == UninitUse::AfterCall ||
1561  U.getKind() == UninitUse::AfterDecl;
1562  });
1563  }
1564 };
1565 } // anonymous namespace
1566 
1567 namespace clang {
1568 namespace {
1570 typedef std::pair<PartialDiagnosticAt, OptionalNotes> DelayedDiag;
1571 typedef std::list<DelayedDiag> DiagList;
1572 
1573 struct SortDiagBySourceLocation {
1575  SortDiagBySourceLocation(SourceManager &SM) : SM(SM) {}
1576 
1577  bool operator()(const DelayedDiag &left, const DelayedDiag &right) {
1578  // Although this call will be slow, this is only called when outputting
1579  // multiple warnings.
1580  return SM.isBeforeInTranslationUnit(left.first.first, right.first.first);
1581  }
1582 };
1583 } // anonymous namespace
1584 } // namespace clang
1585 
1586 //===----------------------------------------------------------------------===//
1587 // -Wthread-safety
1588 //===----------------------------------------------------------------------===//
1589 namespace clang {
1590 namespace threadSafety {
1591 namespace {
1592 class ThreadSafetyReporter : public clang::threadSafety::ThreadSafetyHandler {
1593  Sema &S;
1594  DiagList Warnings;
1595  SourceLocation FunLocation, FunEndLocation;
1596 
1597  const FunctionDecl *CurrentFunction;
1598  bool Verbose;
1599 
1600  OptionalNotes getNotes() const {
1601  if (Verbose && CurrentFunction) {
1602  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getLocStart(),
1603  S.PDiag(diag::note_thread_warning_in_fun)
1604  << CurrentFunction);
1605  return OptionalNotes(1, FNote);
1606  }
1607  return OptionalNotes();
1608  }
1609 
1610  OptionalNotes getNotes(const PartialDiagnosticAt &Note) const {
1611  OptionalNotes ONS(1, Note);
1612  if (Verbose && CurrentFunction) {
1613  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getLocStart(),
1614  S.PDiag(diag::note_thread_warning_in_fun)
1615  << CurrentFunction);
1616  ONS.push_back(std::move(FNote));
1617  }
1618  return ONS;
1619  }
1620 
1621  OptionalNotes getNotes(const PartialDiagnosticAt &Note1,
1622  const PartialDiagnosticAt &Note2) const {
1623  OptionalNotes ONS;
1624  ONS.push_back(Note1);
1625  ONS.push_back(Note2);
1626  if (Verbose && CurrentFunction) {
1627  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getLocStart(),
1628  S.PDiag(diag::note_thread_warning_in_fun)
1629  << CurrentFunction);
1630  ONS.push_back(std::move(FNote));
1631  }
1632  return ONS;
1633  }
1634 
1635  // Helper functions
1636  void warnLockMismatch(unsigned DiagID, StringRef Kind, Name LockName,
1637  SourceLocation Loc) {
1638  // Gracefully handle rare cases when the analysis can't get a more
1639  // precise source location.
1640  if (!Loc.isValid())
1641  Loc = FunLocation;
1642  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind << LockName);
1643  Warnings.emplace_back(std::move(Warning), getNotes());
1644  }
1645 
1646  public:
1647  ThreadSafetyReporter(Sema &S, SourceLocation FL, SourceLocation FEL)
1648  : S(S), FunLocation(FL), FunEndLocation(FEL),
1649  CurrentFunction(nullptr), Verbose(false) {}
1650 
1651  void setVerbose(bool b) { Verbose = b; }
1652 
1653  /// Emit all buffered diagnostics in order of sourcelocation.
1654  /// We need to output diagnostics produced while iterating through
1655  /// the lockset in deterministic order, so this function orders diagnostics
1656  /// and outputs them.
1657  void emitDiagnostics() {
1658  Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1659  for (const auto &Diag : Warnings) {
1660  S.Diag(Diag.first.first, Diag.first.second);
1661  for (const auto &Note : Diag.second)
1662  S.Diag(Note.first, Note.second);
1663  }
1664  }
1665 
1666  void handleInvalidLockExp(StringRef Kind, SourceLocation Loc) override {
1667  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_cannot_resolve_lock)
1668  << Loc);
1669  Warnings.emplace_back(std::move(Warning), getNotes());
1670  }
1671 
1672  void handleUnmatchedUnlock(StringRef Kind, Name LockName,
1673  SourceLocation Loc) override {
1674  warnLockMismatch(diag::warn_unlock_but_no_lock, Kind, LockName, Loc);
1675  }
1676 
1677  void handleIncorrectUnlockKind(StringRef Kind, Name LockName,
1678  LockKind Expected, LockKind Received,
1679  SourceLocation Loc) override {
1680  if (Loc.isInvalid())
1681  Loc = FunLocation;
1682  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_unlock_kind_mismatch)
1683  << Kind << LockName << Received
1684  << Expected);
1685  Warnings.emplace_back(std::move(Warning), getNotes());
1686  }
1687 
1688  void handleDoubleLock(StringRef Kind, Name LockName, SourceLocation Loc) override {
1689  warnLockMismatch(diag::warn_double_lock, Kind, LockName, Loc);
1690  }
1691 
1692  void handleMutexHeldEndOfScope(StringRef Kind, Name LockName,
1693  SourceLocation LocLocked,
1694  SourceLocation LocEndOfScope,
1695  LockErrorKind LEK) override {
1696  unsigned DiagID = 0;
1697  switch (LEK) {
1699  DiagID = diag::warn_lock_some_predecessors;
1700  break;
1702  DiagID = diag::warn_expecting_lock_held_on_loop;
1703  break;
1705  DiagID = diag::warn_no_unlock;
1706  break;
1708  DiagID = diag::warn_expecting_locked;
1709  break;
1710  }
1711  if (LocEndOfScope.isInvalid())
1712  LocEndOfScope = FunEndLocation;
1713 
1714  PartialDiagnosticAt Warning(LocEndOfScope, S.PDiag(DiagID) << Kind
1715  << LockName);
1716  if (LocLocked.isValid()) {
1717  PartialDiagnosticAt Note(LocLocked, S.PDiag(diag::note_locked_here)
1718  << Kind);
1719  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1720  return;
1721  }
1722  Warnings.emplace_back(std::move(Warning), getNotes());
1723  }
1724 
1725  void handleExclusiveAndShared(StringRef Kind, Name LockName,
1726  SourceLocation Loc1,
1727  SourceLocation Loc2) override {
1729  S.PDiag(diag::warn_lock_exclusive_and_shared)
1730  << Kind << LockName);
1731  PartialDiagnosticAt Note(Loc2, S.PDiag(diag::note_lock_exclusive_and_shared)
1732  << Kind << LockName);
1733  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1734  }
1735 
1736  void handleNoMutexHeld(StringRef Kind, const NamedDecl *D,
1738  SourceLocation Loc) override {
1739  assert((POK == POK_VarAccess || POK == POK_VarDereference) &&
1740  "Only works for variables");
1741  unsigned DiagID = POK == POK_VarAccess?
1742  diag::warn_variable_requires_any_lock:
1743  diag::warn_var_deref_requires_any_lock;
1744  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
1745  << D << getLockKindFromAccessKind(AK));
1746  Warnings.emplace_back(std::move(Warning), getNotes());
1747  }
1748 
1749  void handleMutexNotHeld(StringRef Kind, const NamedDecl *D,
1750  ProtectedOperationKind POK, Name LockName,
1751  LockKind LK, SourceLocation Loc,
1752  Name *PossibleMatch) override {
1753  unsigned DiagID = 0;
1754  if (PossibleMatch) {
1755  switch (POK) {
1756  case POK_VarAccess:
1757  DiagID = diag::warn_variable_requires_lock_precise;
1758  break;
1759  case POK_VarDereference:
1760  DiagID = diag::warn_var_deref_requires_lock_precise;
1761  break;
1762  case POK_FunctionCall:
1763  DiagID = diag::warn_fun_requires_lock_precise;
1764  break;
1765  case POK_PassByRef:
1766  DiagID = diag::warn_guarded_pass_by_reference;
1767  break;
1768  case POK_PtPassByRef:
1769  DiagID = diag::warn_pt_guarded_pass_by_reference;
1770  break;
1771  }
1772  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
1773  << D
1774  << LockName << LK);
1775  PartialDiagnosticAt Note(Loc, S.PDiag(diag::note_found_mutex_near_match)
1776  << *PossibleMatch);
1777  if (Verbose && POK == POK_VarAccess) {
1778  PartialDiagnosticAt VNote(D->getLocation(),
1779  S.PDiag(diag::note_guarded_by_declared_here)
1780  << D->getNameAsString());
1781  Warnings.emplace_back(std::move(Warning), getNotes(Note, VNote));
1782  } else
1783  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1784  } else {
1785  switch (POK) {
1786  case POK_VarAccess:
1787  DiagID = diag::warn_variable_requires_lock;
1788  break;
1789  case POK_VarDereference:
1790  DiagID = diag::warn_var_deref_requires_lock;
1791  break;
1792  case POK_FunctionCall:
1793  DiagID = diag::warn_fun_requires_lock;
1794  break;
1795  case POK_PassByRef:
1796  DiagID = diag::warn_guarded_pass_by_reference;
1797  break;
1798  case POK_PtPassByRef:
1799  DiagID = diag::warn_pt_guarded_pass_by_reference;
1800  break;
1801  }
1802  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
1803  << D
1804  << LockName << LK);
1805  if (Verbose && POK == POK_VarAccess) {
1807  S.PDiag(diag::note_guarded_by_declared_here));
1808  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1809  } else
1810  Warnings.emplace_back(std::move(Warning), getNotes());
1811  }
1812  }
1813 
1814  void handleNegativeNotHeld(StringRef Kind, Name LockName, Name Neg,
1815  SourceLocation Loc) override {
1817  S.PDiag(diag::warn_acquire_requires_negative_cap)
1818  << Kind << LockName << Neg);
1819  Warnings.emplace_back(std::move(Warning), getNotes());
1820  }
1821 
1822  void handleFunExcludesLock(StringRef Kind, Name FunName, Name LockName,
1823  SourceLocation Loc) override {
1824  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_fun_excludes_mutex)
1825  << Kind << FunName << LockName);
1826  Warnings.emplace_back(std::move(Warning), getNotes());
1827  }
1828 
1829  void handleLockAcquiredBefore(StringRef Kind, Name L1Name, Name L2Name,
1830  SourceLocation Loc) override {
1832  S.PDiag(diag::warn_acquired_before) << Kind << L1Name << L2Name);
1833  Warnings.emplace_back(std::move(Warning), getNotes());
1834  }
1835 
1836  void handleBeforeAfterCycle(Name L1Name, SourceLocation Loc) override {
1838  S.PDiag(diag::warn_acquired_before_after_cycle) << L1Name);
1839  Warnings.emplace_back(std::move(Warning), getNotes());
1840  }
1841 
1842  void enterFunction(const FunctionDecl* FD) override {
1843  CurrentFunction = FD;
1844  }
1845 
1846  void leaveFunction(const FunctionDecl* FD) override {
1847  CurrentFunction = nullptr;
1848  }
1849 };
1850 } // anonymous namespace
1851 } // namespace threadSafety
1852 } // namespace clang
1853 
1854 //===----------------------------------------------------------------------===//
1855 // -Wconsumed
1856 //===----------------------------------------------------------------------===//
1857 
1858 namespace clang {
1859 namespace consumed {
1860 namespace {
1861 class ConsumedWarningsHandler : public ConsumedWarningsHandlerBase {
1862 
1863  Sema &S;
1864  DiagList Warnings;
1865 
1866 public:
1867 
1868  ConsumedWarningsHandler(Sema &S) : S(S) {}
1869 
1870  void emitDiagnostics() override {
1871  Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1872  for (const auto &Diag : Warnings) {
1873  S.Diag(Diag.first.first, Diag.first.second);
1874  for (const auto &Note : Diag.second)
1875  S.Diag(Note.first, Note.second);
1876  }
1877  }
1878 
1879  void warnLoopStateMismatch(SourceLocation Loc,
1880  StringRef VariableName) override {
1881  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_loop_state_mismatch) <<
1882  VariableName);
1883 
1884  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1885  }
1886 
1887  void warnParamReturnTypestateMismatch(SourceLocation Loc,
1888  StringRef VariableName,
1889  StringRef ExpectedState,
1890  StringRef ObservedState) override {
1891 
1893  diag::warn_param_return_typestate_mismatch) << VariableName <<
1894  ExpectedState << ObservedState);
1895 
1896  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1897  }
1898 
1899  void warnParamTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
1900  StringRef ObservedState) override {
1901 
1903  diag::warn_param_typestate_mismatch) << ExpectedState << ObservedState);
1904 
1905  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1906  }
1907 
1908  void warnReturnTypestateForUnconsumableType(SourceLocation Loc,
1909  StringRef TypeName) override {
1911  diag::warn_return_typestate_for_unconsumable_type) << TypeName);
1912 
1913  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1914  }
1915 
1916  void warnReturnTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
1917  StringRef ObservedState) override {
1918 
1920  diag::warn_return_typestate_mismatch) << ExpectedState << ObservedState);
1921 
1922  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1923  }
1924 
1925  void warnUseOfTempInInvalidState(StringRef MethodName, StringRef State,
1926  SourceLocation Loc) override {
1927 
1929  diag::warn_use_of_temp_in_invalid_state) << MethodName << State);
1930 
1931  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1932  }
1933 
1934  void warnUseInInvalidState(StringRef MethodName, StringRef VariableName,
1935  StringRef State, SourceLocation Loc) override {
1936 
1937  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_use_in_invalid_state) <<
1938  MethodName << VariableName << State);
1939 
1940  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1941  }
1942 };
1943 } // anonymous namespace
1944 } // namespace consumed
1945 } // namespace clang
1946 
1947 //===----------------------------------------------------------------------===//
1948 // AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
1949 // warnings on a function, method, or block.
1950 //===----------------------------------------------------------------------===//
1951 
1953  enableCheckFallThrough = 1;
1954  enableCheckUnreachable = 0;
1955  enableThreadSafetyAnalysis = 0;
1956  enableConsumedAnalysis = 0;
1957 }
1958 
1959 static unsigned isEnabled(DiagnosticsEngine &D, unsigned diag) {
1960  return (unsigned)!D.isIgnored(diag, SourceLocation());
1961 }
1962 
1964  : S(s),
1965  NumFunctionsAnalyzed(0),
1966  NumFunctionsWithBadCFGs(0),
1967  NumCFGBlocks(0),
1968  MaxCFGBlocksPerFunction(0),
1969  NumUninitAnalysisFunctions(0),
1970  NumUninitAnalysisVariables(0),
1971  MaxUninitAnalysisVariablesPerFunction(0),
1972  NumUninitAnalysisBlockVisits(0),
1973  MaxUninitAnalysisBlockVisitsPerFunction(0) {
1974 
1975  using namespace diag;
1977 
1978  DefaultPolicy.enableCheckUnreachable =
1979  isEnabled(D, warn_unreachable) ||
1980  isEnabled(D, warn_unreachable_break) ||
1981  isEnabled(D, warn_unreachable_return) ||
1982  isEnabled(D, warn_unreachable_loop_increment);
1983 
1984  DefaultPolicy.enableThreadSafetyAnalysis =
1985  isEnabled(D, warn_double_lock);
1986 
1987  DefaultPolicy.enableConsumedAnalysis =
1988  isEnabled(D, warn_use_in_invalid_state);
1989 }
1990 
1991 static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope) {
1992  for (const auto &D : fscope->PossiblyUnreachableDiags)
1993  S.Diag(D.Loc, D.PD);
1994 }
1995 
1996 void clang::sema::
1998  sema::FunctionScopeInfo *fscope,
1999  const Decl *D, const BlockExpr *blkExpr) {
2000 
2001  // We avoid doing analysis-based warnings when there are errors for
2002  // two reasons:
2003  // (1) The CFGs often can't be constructed (if the body is invalid), so
2004  // don't bother trying.
2005  // (2) The code already has problems; running the analysis just takes more
2006  // time.
2007  DiagnosticsEngine &Diags = S.getDiagnostics();
2008 
2009  // Do not do any analysis if we are going to just ignore them.
2010  if (Diags.getIgnoreAllWarnings() ||
2011  (Diags.getSuppressSystemWarnings() &&
2013  return;
2014 
2015  // For code in dependent contexts, we'll do this at instantiation time.
2016  if (cast<DeclContext>(D)->isDependentContext())
2017  return;
2018 
2019  if (Diags.hasUncompilableErrorOccurred()) {
2020  // Flush out any possibly unreachable diagnostics.
2021  flushDiagnostics(S, fscope);
2022  return;
2023  }
2024 
2025  const Stmt *Body = D->getBody();
2026  assert(Body);
2027 
2028  // Construct the analysis context with the specified CFG build options.
2029  AnalysisDeclContext AC(/* AnalysisDeclContextManager */ nullptr, D);
2030 
2031  // Don't generate EH edges for CallExprs as we'd like to avoid the n^2
2032  // explosion for destructors that can result and the compile time hit.
2034  AC.getCFGBuildOptions().AddEHEdges = false;
2035  AC.getCFGBuildOptions().AddInitializers = true;
2040 
2041  // Force that certain expressions appear as CFGElements in the CFG. This
2042  // is used to speed up various analyses.
2043  // FIXME: This isn't the right factoring. This is here for initial
2044  // prototyping, but we need a way for analyses to say what expressions they
2045  // expect to always be CFGElements and then fill in the BuildOptions
2046  // appropriately. This is essentially a layering violation.
2047  if (P.enableCheckUnreachable || P.enableThreadSafetyAnalysis ||
2048  P.enableConsumedAnalysis) {
2049  // Unreachable code analysis and thread safety require a linearized CFG.
2051  }
2052  else {
2053  AC.getCFGBuildOptions()
2054  .setAlwaysAdd(Stmt::BinaryOperatorClass)
2055  .setAlwaysAdd(Stmt::CompoundAssignOperatorClass)
2056  .setAlwaysAdd(Stmt::BlockExprClass)
2057  .setAlwaysAdd(Stmt::CStyleCastExprClass)
2058  .setAlwaysAdd(Stmt::DeclRefExprClass)
2059  .setAlwaysAdd(Stmt::ImplicitCastExprClass)
2060  .setAlwaysAdd(Stmt::UnaryOperatorClass)
2061  .setAlwaysAdd(Stmt::AttributedStmtClass);
2062  }
2063 
2064  // Install the logical handler for -Wtautological-overlap-compare
2065  std::unique_ptr<LogicalErrorHandler> LEH;
2066  if (!Diags.isIgnored(diag::warn_tautological_overlap_comparison,
2067  D->getLocStart())) {
2068  LEH.reset(new LogicalErrorHandler(S));
2069  AC.getCFGBuildOptions().Observer = LEH.get();
2070  }
2071 
2072  // Emit delayed diagnostics.
2073  if (!fscope->PossiblyUnreachableDiags.empty()) {
2074  bool analyzed = false;
2075 
2076  // Register the expressions with the CFGBuilder.
2077  for (const auto &D : fscope->PossiblyUnreachableDiags) {
2078  if (D.stmt)
2079  AC.registerForcedBlockExpression(D.stmt);
2080  }
2081 
2082  if (AC.getCFG()) {
2083  analyzed = true;
2084  for (const auto &D : fscope->PossiblyUnreachableDiags) {
2085  bool processed = false;
2086  if (D.stmt) {
2087  const CFGBlock *block = AC.getBlockForRegisteredExpression(D.stmt);
2090  // FIXME: We should be able to assert that block is non-null, but
2091  // the CFG analysis can skip potentially-evaluated expressions in
2092  // edge cases; see test/Sema/vla-2.c.
2093  if (block && cra) {
2094  // Can this block be reached from the entrance?
2095  if (cra->isReachable(&AC.getCFG()->getEntry(), block))
2096  S.Diag(D.Loc, D.PD);
2097  processed = true;
2098  }
2099  }
2100  if (!processed) {
2101  // Emit the warning anyway if we cannot map to a basic block.
2102  S.Diag(D.Loc, D.PD);
2103  }
2104  }
2105  }
2106 
2107  if (!analyzed)
2108  flushDiagnostics(S, fscope);
2109  }
2110 
2111  // Warning: check missing 'return'
2112  if (P.enableCheckFallThrough) {
2113  const CheckFallThroughDiagnostics &CD =
2114  (isa<BlockDecl>(D)
2115  ? CheckFallThroughDiagnostics::MakeForBlock()
2116  : (isa<CXXMethodDecl>(D) &&
2117  cast<CXXMethodDecl>(D)->getOverloadedOperator() == OO_Call &&
2118  cast<CXXMethodDecl>(D)->getParent()->isLambda())
2119  ? CheckFallThroughDiagnostics::MakeForLambda()
2120  : (fscope->isCoroutine()
2121  ? CheckFallThroughDiagnostics::MakeForCoroutine(D)
2122  : CheckFallThroughDiagnostics::MakeForFunction(D)));
2123  CheckFallThroughForBody(S, D, Body, blkExpr, CD, AC, fscope);
2124  }
2125 
2126  // Warning: check for unreachable code
2127  if (P.enableCheckUnreachable) {
2128  // Only check for unreachable code on non-template instantiations.
2129  // Different template instantiations can effectively change the control-flow
2130  // and it is very difficult to prove that a snippet of code in a template
2131  // is unreachable for all instantiations.
2132  bool isTemplateInstantiation = false;
2133  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
2134  isTemplateInstantiation = Function->isTemplateInstantiation();
2135  if (!isTemplateInstantiation)
2136  CheckUnreachable(S, AC);
2137  }
2138 
2139  // Check for thread safety violations
2140  if (P.enableThreadSafetyAnalysis) {
2141  SourceLocation FL = AC.getDecl()->getLocation();
2142  SourceLocation FEL = AC.getDecl()->getLocEnd();
2143  threadSafety::ThreadSafetyReporter Reporter(S, FL, FEL);
2144  if (!Diags.isIgnored(diag::warn_thread_safety_beta, D->getLocStart()))
2145  Reporter.setIssueBetaWarnings(true);
2146  if (!Diags.isIgnored(diag::warn_thread_safety_verbose, D->getLocStart()))
2147  Reporter.setVerbose(true);
2148 
2151  Reporter.emitDiagnostics();
2152  }
2153 
2154  // Check for violations of consumed properties.
2155  if (P.enableConsumedAnalysis) {
2156  consumed::ConsumedWarningsHandler WarningHandler(S);
2157  consumed::ConsumedAnalyzer Analyzer(WarningHandler);
2158  Analyzer.run(AC);
2159  }
2160 
2161  if (!Diags.isIgnored(diag::warn_uninit_var, D->getLocStart()) ||
2162  !Diags.isIgnored(diag::warn_sometimes_uninit_var, D->getLocStart()) ||
2163  !Diags.isIgnored(diag::warn_maybe_uninit_var, D->getLocStart())) {
2164  if (CFG *cfg = AC.getCFG()) {
2165  UninitValsDiagReporter reporter(S);
2167  std::memset(&stats, 0, sizeof(UninitVariablesAnalysisStats));
2168  runUninitializedVariablesAnalysis(*cast<DeclContext>(D), *cfg, AC,
2169  reporter, stats);
2170 
2171  if (S.CollectStats && stats.NumVariablesAnalyzed > 0) {
2172  ++NumUninitAnalysisFunctions;
2173  NumUninitAnalysisVariables += stats.NumVariablesAnalyzed;
2174  NumUninitAnalysisBlockVisits += stats.NumBlockVisits;
2175  MaxUninitAnalysisVariablesPerFunction =
2176  std::max(MaxUninitAnalysisVariablesPerFunction,
2177  stats.NumVariablesAnalyzed);
2178  MaxUninitAnalysisBlockVisitsPerFunction =
2179  std::max(MaxUninitAnalysisBlockVisitsPerFunction,
2180  stats.NumBlockVisits);
2181  }
2182  }
2183  }
2184 
2185  bool FallThroughDiagFull =
2186  !Diags.isIgnored(diag::warn_unannotated_fallthrough, D->getLocStart());
2187  bool FallThroughDiagPerFunction = !Diags.isIgnored(
2188  diag::warn_unannotated_fallthrough_per_function, D->getLocStart());
2189  if (FallThroughDiagFull || FallThroughDiagPerFunction ||
2190  fscope->HasFallthroughStmt) {
2191  DiagnoseSwitchLabelsFallthrough(S, AC, !FallThroughDiagFull);
2192  }
2193 
2194  if (S.getLangOpts().ObjCWeak &&
2195  !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, D->getLocStart()))
2196  diagnoseRepeatedUseOfWeak(S, fscope, D, AC.getParentMap());
2197 
2198 
2199  // Check for infinite self-recursion in functions
2200  if (!Diags.isIgnored(diag::warn_infinite_recursive_function,
2201  D->getLocStart())) {
2202  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
2203  checkRecursiveFunction(S, FD, Body, AC);
2204  }
2205  }
2206 
2207  // Check for throw out of non-throwing function.
2208  if (!Diags.isIgnored(diag::warn_throw_in_noexcept_func, D->getLocStart()))
2209  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
2210  if (S.getLangOpts().CPlusPlus && isNoexcept(FD))
2211  checkThrowInNonThrowingFunc(S, FD, AC);
2212 
2213  // If none of the previous checks caused a CFG build, trigger one here
2214  // for -Wtautological-overlap-compare
2215  if (!Diags.isIgnored(diag::warn_tautological_overlap_comparison,
2216  D->getLocStart())) {
2217  AC.getCFG();
2218  }
2219 
2220  // Collect statistics about the CFG if it was built.
2221  if (S.CollectStats && AC.isCFGBuilt()) {
2222  ++NumFunctionsAnalyzed;
2223  if (CFG *cfg = AC.getCFG()) {
2224  // If we successfully built a CFG for this context, record some more
2225  // detail information about it.
2226  NumCFGBlocks += cfg->getNumBlockIDs();
2227  MaxCFGBlocksPerFunction = std::max(MaxCFGBlocksPerFunction,
2228  cfg->getNumBlockIDs());
2229  } else {
2230  ++NumFunctionsWithBadCFGs;
2231  }
2232  }
2233 }
2234 
2236  llvm::errs() << "\n*** Analysis Based Warnings Stats:\n";
2237 
2238  unsigned NumCFGsBuilt = NumFunctionsAnalyzed - NumFunctionsWithBadCFGs;
2239  unsigned AvgCFGBlocksPerFunction =
2240  !NumCFGsBuilt ? 0 : NumCFGBlocks/NumCFGsBuilt;
2241  llvm::errs() << NumFunctionsAnalyzed << " functions analyzed ("
2242  << NumFunctionsWithBadCFGs << " w/o CFGs).\n"
2243  << " " << NumCFGBlocks << " CFG blocks built.\n"
2244  << " " << AvgCFGBlocksPerFunction
2245  << " average CFG blocks per function.\n"
2246  << " " << MaxCFGBlocksPerFunction
2247  << " max CFG blocks per function.\n";
2248 
2249  unsigned AvgUninitVariablesPerFunction = !NumUninitAnalysisFunctions ? 0
2250  : NumUninitAnalysisVariables/NumUninitAnalysisFunctions;
2251  unsigned AvgUninitBlockVisitsPerFunction = !NumUninitAnalysisFunctions ? 0
2252  : NumUninitAnalysisBlockVisits/NumUninitAnalysisFunctions;
2253  llvm::errs() << NumUninitAnalysisFunctions
2254  << " functions analyzed for uninitialiazed variables\n"
2255  << " " << NumUninitAnalysisVariables << " variables analyzed.\n"
2256  << " " << AvgUninitVariablesPerFunction
2257  << " average variables per function.\n"
2258  << " " << MaxUninitAnalysisVariablesPerFunction
2259  << " max variables per function.\n"
2260  << " " << NumUninitAnalysisBlockVisits << " block visits.\n"
2261  << " " << AvgUninitBlockVisitsPerFunction
2262  << " average block visits per function.\n"
2263  << " " << MaxUninitAnalysisBlockVisitsPerFunction
2264  << " max block visits per function.\n";
2265 }
static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use, bool IsCapturedByBlock)
DiagUninitUse – Helper function to produce a diagnostic for an uninitialized use of a variable...
Represents a function declaration or definition.
Definition: Decl.h:1714
Passing a guarded variable by reference.
Definition: ThreadSafety.h:48
static DiagnosticBuilder Diag(DiagnosticsEngine *Diags, const LangOptions &Features, FullSourceLoc TokLoc, const char *TokBegin, const char *TokRangeBegin, const char *TokRangeEnd, unsigned DiagID)
Produce a diagnostic highlighting some portion of a literal.
const Stmt * getElse() const
Definition: Stmt.h:989
pred_iterator pred_end()
Definition: CFG.h:733
A (possibly-)qualified type.
Definition: Type.h:655
bool isBlockPointerType() const
Definition: Type.h:6057
IdentifierInfo * getIdentifierInfo(StringRef Name) const
Return information about the specified preprocessor identifier token.
bool HasFallthroughStmt
Whether there is a fallthrough statement in this function.
Definition: ScopeInfo.h:126
const Expr * getSubExpr() const
Definition: ExprCXX.h:1007
const Stmt * getStmt() const
Definition: CFG.h:132
Stmt * getBody() const
Get the body of the Declaration.
succ_iterator succ_begin()
Definition: CFG.h:750
virtual Stmt * getBody() const
getBody - If this Decl represents a declaration for a body of code, such as a function or method defi...
Definition: DeclBase.h:984
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3148
CFGBlock & getEntry()
Definition: CFG.h:1091
IfStmt - This represents an if/then/else.
Definition: Stmt.h:949
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:460
Defines the SourceManager interface.
static void diagnoseRepeatedUseOfWeak(Sema &S, const sema::FunctionScopeInfo *CurFn, const Decl *D, const ParentMap &PM)
unsigned getBlockID() const
Definition: CFG.h:855
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID)
Emit a diagnostic.
Definition: Sema.h:1270
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:86
Expr * getImplicitObjectArgument() const
Retrieves the implicit object argument for the member call.
Definition: ExprCXX.cpp:505
bool isVirtual() const
Definition: DeclCXX.h:2076
Opcode getOpcode() const
Definition: Expr.h:3106
StringRef P
Represents an attribute applied to a statement.
Definition: Stmt.h:897
bool isBeforeInTranslationUnit(SourceLocation LHS, SourceLocation RHS) const
Determines the order of 2 source locations in the translation unit.
bool getAddEHEdges() const
getAddEHEdges - Return true iff we are adding exceptional edges from callExprs.
const WeakObjectUseMap & getWeakObjectUses() const
Definition: ScopeInfo.h:381
The use is uninitialized whenever a certain branch is taken.
Stmt * getParent(Stmt *) const
Definition: ParentMap.cpp:123
iterator begin()
Definition: CFG.h:702
StringRef getLastMacroWithSpelling(SourceLocation Loc, ArrayRef< TokenValue > Tokens) const
Return the name of the macro defined before Loc that has spelling Tokens.
SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset=0)
Calls Lexer::getLocForEndOfToken()
Definition: Sema.cpp:46
T castAs() const
Convert to the specified CFGElement type, asserting that this CFGElement is of the desired type...
Definition: CFG.h:98
bool getSuppressSystemWarnings() const
Definition: Diagnostic.h:625
LockKind getLockKindFromAccessKind(AccessKind AK)
Helper function that returns a LockKind required for the given level of access.
SourceLocation getLocEnd() const LLVM_READONLY
Definition: DeclBase.h:413
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:778
static std::pair< const Stmt *, const CFGBlock * > getLastStmt(const ExplodedNode *Node)
ProtectedOperationKind
This enum distinguishes between different kinds of operations that may need to be protected by locks...
Definition: ThreadSafety.h:37
Retains information about a function, method, or block that is currently being parsed.
Definition: ScopeInfo.h:96
bool EvaluateAsInt(llvm::APSInt &Result, const ASTContext &Ctx, SideEffectsKind AllowSideEffects=SE_NoSideEffects) const
EvaluateAsInt - Return true if this is a constant which we can fold and convert to an integer...
Represents a variable declaration or definition.
Definition: Decl.h:812
PartialDiagnostic PDiag(unsigned DiagID=0)
Build a partial diagnostic.
Definition: SemaInternal.h:25
ASTContext & getASTContext() const
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6456
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:139
The use might be uninitialized.
Defines the Objective-C statement AST node classes.
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:985
Defines the clang::Expr interface and subclasses for C++ expressions.
SourceLocation getLocStart() const LLVM_READONLY
Definition: Expr.h:4954
branch_iterator branch_end() const
LabelStmt - Represents a label, which has a substatement.
Definition: Stmt.h:858
LockKind
This enum distinguishes between different kinds of lock actions.
Definition: ThreadSafety.h:57
bool pred_empty() const
Definition: CFG.h:772
DeclarationName getDeclName() const
Get the actual, stored name of the declaration, which may be a special name.
Definition: Decl.h:297
Kind getKind() const
Get the kind of uninitialized use.
Expr * getFalseExpr() const
Definition: Expr.h:3392
SourceLocation getBegin() const
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:150
LineState State
branch_iterator branch_begin() const
Branches which inevitably result in the variable being used uninitialized.
AnalysisDeclContext contains the context data for the function or method under analysis.
threadSafety::BeforeSet * ThreadSafetyDeclCache
Definition: Sema.h:7588
static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC, bool PerFunction)
succ_range succs()
Definition: CFG.h:760
const LangOptions & getLangOpts() const
Definition: Preprocessor.h:815
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:726
TextDiagnosticBuffer::DiagList DiagList
Stmt * getBody(const FunctionDecl *&Definition) const
Retrieve the body (definition) of the function.
Definition: Decl.cpp:2662
bool AddCXXDefaultInitExprInCtors
Definition: CFG.h:1026
CFGReverseBlockReachabilityAnalysis * getCFGReachablityAnalysis()
CFGCallback * Observer
Definition: CFG.h:1015
child_range children()
Definition: Stmt.cpp:227
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:149
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3065
void IssueWarnings(Policy P, FunctionScopeInfo *fscope, const Decl *D, const BlockExpr *blkExpr)
static StringRef getFallthroughAttrSpelling(Preprocessor &PP, SourceLocation Loc)
SourceLocation getThrowLoc() const
Definition: ExprCXX.h:1010
Expr * IgnoreParenCasts() LLVM_READONLY
IgnoreParenCasts - Ignore parentheses and casts.
Definition: Expr.cpp:2500
static void CheckUnreachable(Sema &S, AnalysisDeclContext &AC)
CheckUnreachable - Check for unreachable code.
DeclContext * getLexicalDeclContext()
getLexicalDeclContext - The declaration context where this Decl was lexically declared (LexicalDC)...
Definition: DeclBase.h:826
__DEVICE__ void * memset(void *__a, int __b, size_t __c)
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1583
const LangOptions & getLangOpts() const
Definition: Sema.h:1193
SourceRange getExceptionSpecSourceRange() const
Attempt to compute an informative source range covering the function exception specification, if any.
Definition: Decl.cpp:3130
A class that does preorder or postorder depth-first traversal on the entire Clang AST and visits each...
virtual Decl * getCanonicalDecl()
Retrieves the "canonical" declaration of the given declaration.
Definition: DeclBase.h:875
reverse_iterator rend()
Definition: CFG.h:708
static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD)
DiagnosticsEngine & getDiagnostics() const
Definition: Sema.h:1197
Passing a pt-guarded variable by reference.
Definition: ThreadSafety.h:51
bool hasAttr() const
Definition: DeclBase.h:536
ConditionalOperator - The ?: ternary operator.
Definition: Expr.h:3349
Sema - This implements semantic analysis and AST building for C.
Definition: Sema.h:276
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3369
static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD, const UninitUse &Use, bool alwaysReportSelfInit=false)
DiagnoseUninitializedUse – Helper function for diagnosing uses of an uninitialized variable...
Handler class for thread safety warnings.
Definition: ThreadSafety.h:94
SourceLocation getLocEnd() const LLVM_READONLY
Definition: Stmt.cpp:291
OverloadedOperatorKind getCXXOverloadedOperator() const
getCXXOverloadedOperator - If this name is the name of an overloadable operator in C++ (e...
static StringRef getOpcodeStr(Opcode Op)
getOpcodeStr - Turn an Opcode enum value into the punctuation char it corresponds to...
Definition: Expr.cpp:1793
CFGBlock - Represents a single basic block in a source-level CFG.
Definition: CFG.h:548
static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM, const Stmt *S)
SourceManager & SM
Dereferencing a variable (e.g. p in *p = 5;)
Definition: ThreadSafety.h:39
Expr * getCond() const
Definition: Expr.h:3383
Expr - This represents one expression.
Definition: Expr.h:106
std::string Label
CFG - Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:1002
bool isInSystemHeader(SourceLocation Loc) const
Returns if a SourceLocation is in a system header.
bool hasUncompilableErrorOccurred() const
Errors that actually prevent compilation, not those that are upgraded from a warning by -Werror...
Definition: Diagnostic.h:750
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6519
const Stmt * getThen() const
Definition: Stmt.h:987
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:4931
const Expr * getCallee() const
Definition: Expr.h:2323
Defines the clang::Preprocessor interface.
Stores token information for comparing actual tokens with predefined values.
Definition: Preprocessor.h:88
void runUninitializedVariablesAnalysis(const DeclContext &dc, const CFG &cfg, AnalysisDeclContext &ac, UninitVariablesHandler &handler, UninitVariablesAnalysisStats &stats)
void FindUnreachableCode(AnalysisDeclContext &AC, Preprocessor &PP, Callback &CB)
unsigned ScanReachableFromBlock(const CFGBlock *Start, llvm::BitVector &Reachable)
ScanReachableFromBlock - Mark all blocks reachable from Start.
QualType getType() const
Definition: Expr.h:128
std::pair< PartialDiagnosticAt, OptionalNotes > DelayedDiag
Definition: Consumed.h:54
const CFGBlock * getBlockForRegisteredExpression(const Stmt *stmt)
bool handlerCanCatch(QualType HandlerType, QualType ExceptionType)
AccessKind
This enum distinguishes between different ways to access (read or write) a variable.
Definition: ThreadSafety.h:70
SourceLocation getEnd() const
Making a function call (e.g. fool())
Definition: ThreadSafety.h:45
CXXMethodDecl * getMethodDecl() const
Retrieves the declaration of the called method.
Definition: ExprCXX.cpp:517
Preprocessor & getPreprocessor() const
Definition: Sema.h:1199
A use of a variable, which might be uninitialized.
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:720
bool isTemplateInstantiation(TemplateSpecializationKind Kind)
Determine whether this template specialization kind refers to an instantiation of an entity (as oppos...
Definition: Specifiers.h:170
reverse_iterator rbegin()
Definition: CFG.h:707
VarDecl * CoroutinePromise
The promise object for this coroutine, if any.
Definition: ScopeInfo.h:188
static CharSourceRange getCharRange(SourceRange R)
CharSourceRange RemoveRange
Code that should be replaced to correct the error.
Definition: Diagnostic.h:70
SourceLocation getLocStart() const LLVM_READONLY
Definition: DeclBase.h:409
CFGTerminator getTerminator()
Definition: CFG.h:839
Kind
QualType getCanonicalType() const
Definition: Type.h:5864
Reading or writing a variable (e.g. x in x = 5;)
Definition: ThreadSafety.h:42
ASTContext & getASTContext() const
Definition: Sema.h:1200
Encodes a location in the source.
BuildOptions & setAlwaysAdd(Stmt::StmtClass stmtClass, bool val=true)
Definition: CFG.h:1035
static void visitReachableThrows(CFG *BodyCFG, llvm::function_ref< void(const CXXThrowExpr *, CFGBlock &)> Visit)
SourceLocation getOperatorLoc() const
Definition: Expr.h:3103
static void EmitDiagForCXXThrowInNonThrowingFunc(Sema &S, SourceLocation OpLoc, const FunctionDecl *FD)
Stmt * getLabel()
Definition: CFG.h:850
std::string getNameAsString() const
Get a human-readable name for the declaration, even if it is one of the special kinds of names (C++ c...
Definition: Decl.h:291
bool isReachable(const CFGBlock *Src, const CFGBlock *Dst)
Returns true if the block &#39;Dst&#39; can be reached from block &#39;Src&#39;.
SourceLocation getLocStart() const LLVM_READONLY
Definition: Expr.h:3114
Represents a call to a member function that may be written either with member call syntax (e...
Definition: ExprCXX.h:164
bool PruneTriviallyFalseEdges
Definition: CFG.h:1016
std::pair< SourceLocation, PartialDiagnostic > PartialDiagnosticAt
A partial diagnostic along with the source location where this diagnostic occurs. ...
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:2031
bool isCFGBuilt() const
Returns true if we have built a CFG for this analysis context.
Represents a C++ nested name specifier, such as "\::std::vector<int>::".
bool CollectStats
Flag indicating whether or not to collect detailed statistics.
Definition: Sema.h:324
bool isInMainFile(SourceLocation Loc) const
Returns whether the PresumedLoc for a given SourceLocation is in the main file.
const Decl * getDecl() const
static void checkThrowInNonThrowingFunc(Sema &S, const FunctionDecl *FD, AnalysisDeclContext &AC)
Represents one property declaration in an Objective-C interface.
Definition: DeclObjC.h:746
unsigned getNumBlockIDs() const
getNumBlockIDs - Returns the total number of BlockIDs allocated (which start at 0).
Definition: CFG.h:1168
SourceRange getSourceRange() const override LLVM_READONLY
Source range that this declaration covers.
Definition: Decl.cpp:1938
static bool isLogicalOp(Opcode Opc)
Definition: Expr.h:3185
static void emitDiagnostics(BoundNodes &Match, const Decl *D, BugReporter &BR, AnalysisManager &AM, const ObjCAutoreleaseWriteChecker *Checker)
succ_iterator succ_end()
Definition: CFG.h:751
BuildOptions & setAllAlwaysAdd()
Definition: CFG.h:1040
The use is uninitialized the first time it is reached after we reach the variable&#39;s declaration...
std::string getFixItZeroInitializerForType(QualType T, SourceLocation Loc) const
Get a string to suggest for zero-initialization of a type.
static unsigned isEnabled(DiagnosticsEngine &D, unsigned diag)
SourceLocation getExprLoc() const LLVM_READONLY
getExprLoc - Return the preferred location for the arrow when diagnosing a problem with a generic exp...
Definition: Expr.cpp:216
bool getIgnoreAllWarnings() const
Definition: Diagnostic.h:590
Optional< T > getAs() const
Convert to the specified CFGElement type, returning None if this CFGElement is not of the desired typ...
Definition: CFG.h:109
Expr * getLHS() const
Definition: Expr.h:3109
pred_iterator pred_begin()
Definition: CFG.h:732
SmallVectorImpl< Branch >::const_iterator branch_iterator
Dataflow Directional Tag Classes.
CFG::BuildOptions & getCFGBuildOptions()
Return the build options used to construct the CFG.
bool isValid() const
Return true if this is a valid SourceLocation object.
void runThreadSafetyAnalysis(AnalysisDeclContext &AC, ThreadSafetyHandler &Handler, BeforeSet **Bset)
Check a function&#39;s CFG for thread-safety violations.
static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then, const Stmt *Else, bool CondVal, FixItHint &Fixit1, FixItHint &Fixit2)
Create a fixit to remove an if-like statement, on the assumption that its condition is CondVal...
static FixItHint CreateRemoval(CharSourceRange RemoveRange)
Create a code modification hint that removes the given source range.
Definition: Diagnostic.h:118
const Expr * getInit() const
Definition: Decl.h:1217
static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg)
StmtClass getStmtClass() const
Definition: Stmt.h:389
Represents a simple identification of a weak object.
Definition: ScopeInfo.h:233
SourceLocation getLocStart() const LLVM_READONLY
Definition: Decl.h:738
A class that handles the analysis of uniqueness violations.
Definition: Consumed.h:241
ConstEvaluatedExprVisitor - This class visits &#39;const Expr *&#39;s.
static bool isNoexcept(const FunctionDecl *FD)
Expr * IgnoreParenImpCasts() LLVM_READONLY
IgnoreParenImpCasts - Ignore parentheses and implicit casts.
Definition: Expr.cpp:2587
Decl * getCalleeDecl()
Definition: Expr.cpp:1251
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:1027
The standard open() call: int open(const char *path, int oflag, ...);.
UnreachableKind
Classifications of unreachable code.
Definition: ReachableCode.h:41
const Expr * getUser() const
Get the expression containing the uninitialized use.
The use is always uninitialized.
static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body, const BlockExpr *blkExpr, const CheckFallThroughDiagnostics &CD, AnalysisDeclContext &AC, sema::FunctionScopeInfo *FSI)
CheckFallThroughForBody - Check that we don&#39;t fall off the end of a function that should return a val...
TypeSourceInfo * getTypeSourceInfo() const
Definition: Decl.h:715
static bool throwEscapes(Sema &S, const CXXThrowExpr *E, CFGBlock &ThrowBlock, CFG *Body)
Determine whether an exception thrown by E, unwinding from ThrowBlock, can reach ExitBlock.
static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD, const Stmt *Body, AnalysisDeclContext &AC)
static FixItHint CreateInsertion(SourceLocation InsertionLoc, StringRef Code, bool BeforePreviousInsertions=false)
Create a code modification hint that inserts the given code string at a specific location.
Definition: Diagnostic.h:92
SourceLocation getExprLoc() const LLVM_READONLY
Definition: Expr.h:3102
static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope)
Stmt * getSubStmt()
Definition: Stmt.cpp:886
bool hasNoReturnElement() const
Definition: CFG.h:853
SmallVector< PartialDiagnosticAt, 1 > OptionalNotes
Definition: Consumed.h:53
Defines the C++ Decl subclasses, other than those for templates (found in DeclTemplate.h) and friends (in DeclFriend.h).
Defines the clang::SourceLocation class and associated facilities.
SmallVector< PossiblyUnreachableDiag, 4 > PossiblyUnreachableDiags
A list of PartialDiagnostics created but delayed within the current function scope.
Definition: ScopeInfo.h:204
CFGCallback defines methods that should be called when a logical operator error is found when buildin...
Definition: CFG.h:985
bool isValid() const
Expr * getTrueExpr() const
Definition: Expr.h:3387
void run(AnalysisDeclContext &AC)
Check a function&#39;s CFG for consumed violations.
Definition: Consumed.cpp:1309
CFGElement - Represents a top-level expression in a basic block.
Definition: CFG.h:55
static FixItHint CreateReplacement(CharSourceRange RemoveRange, StringRef Code)
Create a code modification hint that replaces the given source range with the given code string...
Definition: Diagnostic.h:129
SourceManager & getSourceManager() const
Definition: Sema.h:1198
static ControlFlowKind CheckFallThrough(AnalysisDeclContext &AC)
CheckFallThrough - Check that we don&#39;t fall off the end of a Statement that should return a value...
SourceRange getSourceRange() const LLVM_READONLY
SourceLocation tokens are not useful in isolation - they are low level value objects created/interpre...
Definition: Stmt.cpp:266
The use is uninitialized the first time it is reached after the function is called.
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2283
void registerForcedBlockExpression(const Stmt *stmt)
__DEVICE__ int max(int __a, int __b)
llvm::SmallDenseMap< WeakObjectProfileTy, WeakUseVector, 8, WeakObjectProfileTy::DenseMapInfo > WeakObjectUseMap
Used to collect all uses of weak objects in a function body.
Definition: ScopeInfo.h:342
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:972
bool isIgnored(unsigned DiagID, SourceLocation Loc) const
Determine whether the diagnostic is known to be ignored.
Definition: Diagnostic.h:818
TemplatedKind getTemplatedKind() const
What kind of templated function this is.
Definition: Decl.cpp:3241
SourceManager & SourceMgr
Definition: Sema.h:321
Annotates a diagnostic with some code that should be inserted, removed, or replaced to fix the proble...
Definition: Diagnostic.h:66
Stmt * getSubStmt()
Definition: Stmt.h:878
QualType getType() const
Definition: Decl.h:647
const Expr * getCond() const
Definition: Stmt.h:985
A trivial tuple used to represent a source range.
ASTContext & Context
Definition: Sema.h:318
FunctionDecl * getCanonicalDecl() override
Retrieves the "canonical" declaration of the given declaration.
Definition: Decl.cpp:2891
This represents a decl that may have a name.
Definition: Decl.h:248
iterator end()
Definition: CFG.h:703
SourceLocation getLocStart() const LLVM_READONLY
Definition: Stmt.cpp:278
SourceLocation getBegin() const
const LangOptions & getLangOpts() const
Definition: ASTContext.h:689
static bool hasRecursiveCallInPath(const FunctionDecl *FD, CFGBlock &Block)
This class handles loading and caching of source files into memory.
SourceLocation getLocation() const
Definition: DeclBase.h:417
QualType getType() const
Return the type wrapped by this type source info.
Definition: Decl.h:97
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:127
CFGBlock & getExit()
Definition: CFG.h:1093