clang  7.0.0
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  cfg->getExit().filtered_pred_start_end(FO);
422  I.hasMore(); ++I) {
423  const CFGBlock &B = **I;
424  if (!live[B.getBlockID()])
425  continue;
426 
427  // Skip blocks which contain an element marked as no-return. They don't
428  // represent actually viable edges into the exit block, so mark them as
429  // abnormal.
430  if (B.hasNoReturnElement()) {
431  HasAbnormalEdge = true;
432  continue;
433  }
434 
435  // Destructors can appear after the 'return' in the CFG. This is
436  // normal. We need to look pass the destructors for the return
437  // statement (if it exists).
438  CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend();
439 
440  for ( ; ri != re ; ++ri)
441  if (ri->getAs<CFGStmt>())
442  break;
443 
444  // No more CFGElements in the block?
445  if (ri == re) {
446  if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) {
447  HasAbnormalEdge = true;
448  continue;
449  }
450  // A labeled empty statement, or the entry block...
451  HasPlainEdge = true;
452  continue;
453  }
454 
455  CFGStmt CS = ri->castAs<CFGStmt>();
456  const Stmt *S = CS.getStmt();
457  if (isa<ReturnStmt>(S) || isa<CoreturnStmt>(S)) {
458  HasLiveReturn = true;
459  continue;
460  }
461  if (isa<ObjCAtThrowStmt>(S)) {
462  HasFakeEdge = true;
463  continue;
464  }
465  if (isa<CXXThrowExpr>(S)) {
466  HasFakeEdge = true;
467  continue;
468  }
469  if (isa<MSAsmStmt>(S)) {
470  // TODO: Verify this is correct.
471  HasFakeEdge = true;
472  HasLiveReturn = true;
473  continue;
474  }
475  if (isa<CXXTryStmt>(S)) {
476  HasAbnormalEdge = true;
477  continue;
478  }
479  if (std::find(B.succ_begin(), B.succ_end(), &cfg->getExit())
480  == B.succ_end()) {
481  HasAbnormalEdge = true;
482  continue;
483  }
484 
485  HasPlainEdge = true;
486  }
487  if (!HasPlainEdge) {
488  if (HasLiveReturn)
489  return NeverFallThrough;
491  }
492  if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
493  return MaybeFallThrough;
494  // This says AlwaysFallThrough for calls to functions that are not marked
495  // noreturn, that don't return. If people would like this warning to be more
496  // accurate, such functions should be marked as noreturn.
497  return AlwaysFallThrough;
498 }
499 
500 namespace {
501 
502 struct CheckFallThroughDiagnostics {
503  unsigned diag_MaybeFallThrough_HasNoReturn;
504  unsigned diag_MaybeFallThrough_ReturnsNonVoid;
505  unsigned diag_AlwaysFallThrough_HasNoReturn;
506  unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
507  unsigned diag_NeverFallThroughOrReturn;
508  enum { Function, Block, Lambda, Coroutine } funMode;
509  SourceLocation FuncLoc;
510 
511  static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
512  CheckFallThroughDiagnostics D;
513  D.FuncLoc = Func->getLocation();
514  D.diag_MaybeFallThrough_HasNoReturn =
515  diag::warn_falloff_noreturn_function;
516  D.diag_MaybeFallThrough_ReturnsNonVoid =
517  diag::warn_maybe_falloff_nonvoid_function;
518  D.diag_AlwaysFallThrough_HasNoReturn =
519  diag::warn_falloff_noreturn_function;
520  D.diag_AlwaysFallThrough_ReturnsNonVoid =
521  diag::warn_falloff_nonvoid_function;
522 
523  // Don't suggest that virtual functions be marked "noreturn", since they
524  // might be overridden by non-noreturn functions.
525  bool isVirtualMethod = false;
526  if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Func))
527  isVirtualMethod = Method->isVirtual();
528 
529  // Don't suggest that template instantiations be marked "noreturn"
530  bool isTemplateInstantiation = false;
531  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Func))
532  isTemplateInstantiation = Function->isTemplateInstantiation();
533 
534  if (!isVirtualMethod && !isTemplateInstantiation)
535  D.diag_NeverFallThroughOrReturn =
536  diag::warn_suggest_noreturn_function;
537  else
538  D.diag_NeverFallThroughOrReturn = 0;
539 
540  D.funMode = Function;
541  return D;
542  }
543 
544  static CheckFallThroughDiagnostics MakeForCoroutine(const Decl *Func) {
545  CheckFallThroughDiagnostics D;
546  D.FuncLoc = Func->getLocation();
547  D.diag_MaybeFallThrough_HasNoReturn = 0;
548  D.diag_MaybeFallThrough_ReturnsNonVoid =
549  diag::warn_maybe_falloff_nonvoid_coroutine;
550  D.diag_AlwaysFallThrough_HasNoReturn = 0;
551  D.diag_AlwaysFallThrough_ReturnsNonVoid =
552  diag::warn_falloff_nonvoid_coroutine;
553  D.funMode = Coroutine;
554  return D;
555  }
556 
557  static CheckFallThroughDiagnostics MakeForBlock() {
558  CheckFallThroughDiagnostics D;
559  D.diag_MaybeFallThrough_HasNoReturn =
560  diag::err_noreturn_block_has_return_expr;
561  D.diag_MaybeFallThrough_ReturnsNonVoid =
562  diag::err_maybe_falloff_nonvoid_block;
563  D.diag_AlwaysFallThrough_HasNoReturn =
564  diag::err_noreturn_block_has_return_expr;
565  D.diag_AlwaysFallThrough_ReturnsNonVoid =
566  diag::err_falloff_nonvoid_block;
567  D.diag_NeverFallThroughOrReturn = 0;
568  D.funMode = Block;
569  return D;
570  }
571 
572  static CheckFallThroughDiagnostics MakeForLambda() {
573  CheckFallThroughDiagnostics D;
574  D.diag_MaybeFallThrough_HasNoReturn =
575  diag::err_noreturn_lambda_has_return_expr;
576  D.diag_MaybeFallThrough_ReturnsNonVoid =
577  diag::warn_maybe_falloff_nonvoid_lambda;
578  D.diag_AlwaysFallThrough_HasNoReturn =
579  diag::err_noreturn_lambda_has_return_expr;
580  D.diag_AlwaysFallThrough_ReturnsNonVoid =
581  diag::warn_falloff_nonvoid_lambda;
582  D.diag_NeverFallThroughOrReturn = 0;
583  D.funMode = Lambda;
584  return D;
585  }
586 
587  bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
588  bool HasNoReturn) const {
589  if (funMode == Function) {
590  return (ReturnsVoid ||
591  D.isIgnored(diag::warn_maybe_falloff_nonvoid_function,
592  FuncLoc)) &&
593  (!HasNoReturn ||
594  D.isIgnored(diag::warn_noreturn_function_has_return_expr,
595  FuncLoc)) &&
596  (!ReturnsVoid ||
597  D.isIgnored(diag::warn_suggest_noreturn_block, FuncLoc));
598  }
599  if (funMode == Coroutine) {
600  return (ReturnsVoid ||
601  D.isIgnored(diag::warn_maybe_falloff_nonvoid_function, FuncLoc) ||
602  D.isIgnored(diag::warn_maybe_falloff_nonvoid_coroutine,
603  FuncLoc)) &&
604  (!HasNoReturn);
605  }
606  // For blocks / lambdas.
607  return ReturnsVoid && !HasNoReturn;
608  }
609 };
610 
611 } // anonymous namespace
612 
613 /// CheckFallThroughForBody - Check that we don't fall off the end of a
614 /// function that should return a value. Check that we don't fall off the end
615 /// of a noreturn function. We assume that functions and blocks not marked
616 /// noreturn will return.
617 static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
618  const BlockExpr *blkExpr,
619  const CheckFallThroughDiagnostics &CD,
622 
623  bool ReturnsVoid = false;
624  bool HasNoReturn = false;
625  bool IsCoroutine = FSI->isCoroutine();
626 
627  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
628  if (const auto *CBody = dyn_cast<CoroutineBodyStmt>(Body))
629  ReturnsVoid = CBody->getFallthroughHandler() != nullptr;
630  else
631  ReturnsVoid = FD->getReturnType()->isVoidType();
632  HasNoReturn = FD->isNoReturn();
633  }
634  else if (const auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
635  ReturnsVoid = MD->getReturnType()->isVoidType();
636  HasNoReturn = MD->hasAttr<NoReturnAttr>();
637  }
638  else if (isa<BlockDecl>(D)) {
639  QualType BlockTy = blkExpr->getType();
640  if (const FunctionType *FT =
641  BlockTy->getPointeeType()->getAs<FunctionType>()) {
642  if (FT->getReturnType()->isVoidType())
643  ReturnsVoid = true;
644  if (FT->getNoReturnAttr())
645  HasNoReturn = true;
646  }
647  }
648 
649  DiagnosticsEngine &Diags = S.getDiagnostics();
650 
651  // Short circuit for compilation speed.
652  if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn))
653  return;
654  SourceLocation LBrace = Body->getLocStart(), RBrace = Body->getLocEnd();
655  auto EmitDiag = [&](SourceLocation Loc, unsigned DiagID) {
656  if (IsCoroutine)
657  S.Diag(Loc, DiagID) << FSI->CoroutinePromise->getType();
658  else
659  S.Diag(Loc, DiagID);
660  };
661 
662  // cpu_dispatch functions permit empty function bodies for ICC compatibility.
664  return;
665 
666  // Either in a function body compound statement, or a function-try-block.
667  switch (CheckFallThrough(AC)) {
668  case UnknownFallThrough:
669  break;
670 
671  case MaybeFallThrough:
672  if (HasNoReturn)
673  EmitDiag(RBrace, CD.diag_MaybeFallThrough_HasNoReturn);
674  else if (!ReturnsVoid)
675  EmitDiag(RBrace, CD.diag_MaybeFallThrough_ReturnsNonVoid);
676  break;
677  case AlwaysFallThrough:
678  if (HasNoReturn)
679  EmitDiag(RBrace, CD.diag_AlwaysFallThrough_HasNoReturn);
680  else if (!ReturnsVoid)
681  EmitDiag(RBrace, CD.diag_AlwaysFallThrough_ReturnsNonVoid);
682  break;
684  if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
685  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
686  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 0 << FD;
687  } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
688  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 1 << MD;
689  } else {
690  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn);
691  }
692  }
693  break;
694  case NeverFallThrough:
695  break;
696  }
697 }
698 
699 //===----------------------------------------------------------------------===//
700 // -Wuninitialized
701 //===----------------------------------------------------------------------===//
702 
703 namespace {
704 /// ContainsReference - A visitor class to search for references to
705 /// a particular declaration (the needle) within any evaluated component of an
706 /// expression (recursively).
707 class ContainsReference : public ConstEvaluatedExprVisitor<ContainsReference> {
708  bool FoundReference;
709  const DeclRefExpr *Needle;
710 
711 public:
713 
714  ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
715  : Inherited(Context), FoundReference(false), Needle(Needle) {}
716 
717  void VisitExpr(const Expr *E) {
718  // Stop evaluating if we already have a reference.
719  if (FoundReference)
720  return;
721 
722  Inherited::VisitExpr(E);
723  }
724 
725  void VisitDeclRefExpr(const DeclRefExpr *E) {
726  if (E == Needle)
727  FoundReference = true;
728  else
729  Inherited::VisitDeclRefExpr(E);
730  }
731 
732  bool doesContainReference() const { return FoundReference; }
733 };
734 } // anonymous namespace
735 
736 static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
737  QualType VariableTy = VD->getType().getCanonicalType();
738  if (VariableTy->isBlockPointerType() &&
739  !VD->hasAttr<BlocksAttr>()) {
740  S.Diag(VD->getLocation(), diag::note_block_var_fixit_add_initialization)
741  << VD->getDeclName()
742  << FixItHint::CreateInsertion(VD->getLocation(), "__block ");
743  return true;
744  }
745 
746  // Don't issue a fixit if there is already an initializer.
747  if (VD->getInit())
748  return false;
749 
750  // Don't suggest a fixit inside macros.
751  if (VD->getLocEnd().isMacroID())
752  return false;
753 
755 
756  // Suggest possible initialization (if any).
757  std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
758  if (Init.empty())
759  return false;
760 
761  S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName()
762  << FixItHint::CreateInsertion(Loc, Init);
763  return true;
764 }
765 
766 /// Create a fixit to remove an if-like statement, on the assumption that its
767 /// condition is CondVal.
768 static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then,
769  const Stmt *Else, bool CondVal,
770  FixItHint &Fixit1, FixItHint &Fixit2) {
771  if (CondVal) {
772  // If condition is always true, remove all but the 'then'.
773  Fixit1 = FixItHint::CreateRemoval(
775  Then->getLocStart()));
776  if (Else) {
777  SourceLocation ElseKwLoc = S.getLocForEndOfToken(Then->getLocEnd());
778  Fixit2 = FixItHint::CreateRemoval(
779  SourceRange(ElseKwLoc, Else->getLocEnd()));
780  }
781  } else {
782  // If condition is always false, remove all but the 'else'.
783  if (Else)
784  Fixit1 = FixItHint::CreateRemoval(
786  Else->getLocStart()));
787  else
789  }
790 }
791 
792 /// DiagUninitUse -- Helper function to produce a diagnostic for an
793 /// uninitialized use of a variable.
794 static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
795  bool IsCapturedByBlock) {
796  bool Diagnosed = false;
797 
798  switch (Use.getKind()) {
799  case UninitUse::Always:
800  S.Diag(Use.getUser()->getLocStart(), diag::warn_uninit_var)
801  << VD->getDeclName() << IsCapturedByBlock
802  << Use.getUser()->getSourceRange();
803  return;
804 
807  S.Diag(VD->getLocation(), diag::warn_sometimes_uninit_var)
808  << VD->getDeclName() << IsCapturedByBlock
809  << (Use.getKind() == UninitUse::AfterDecl ? 4 : 5)
810  << const_cast<DeclContext*>(VD->getLexicalDeclContext())
811  << VD->getSourceRange();
812  S.Diag(Use.getUser()->getLocStart(), diag::note_uninit_var_use)
813  << IsCapturedByBlock << Use.getUser()->getSourceRange();
814  return;
815 
816  case UninitUse::Maybe:
818  // Carry on to report sometimes-uninitialized branches, if possible,
819  // or a 'may be used uninitialized' diagnostic otherwise.
820  break;
821  }
822 
823  // Diagnose each branch which leads to a sometimes-uninitialized use.
824  for (UninitUse::branch_iterator I = Use.branch_begin(), E = Use.branch_end();
825  I != E; ++I) {
826  assert(Use.getKind() == UninitUse::Sometimes);
827 
828  const Expr *User = Use.getUser();
829  const Stmt *Term = I->Terminator;
830 
831  // Information used when building the diagnostic.
832  unsigned DiagKind;
833  StringRef Str;
834  SourceRange Range;
835 
836  // FixIts to suppress the diagnostic by removing the dead condition.
837  // For all binary terminators, branch 0 is taken if the condition is true,
838  // and branch 1 is taken if the condition is false.
839  int RemoveDiagKind = -1;
840  const char *FixitStr =
841  S.getLangOpts().CPlusPlus ? (I->Output ? "true" : "false")
842  : (I->Output ? "1" : "0");
843  FixItHint Fixit1, Fixit2;
844 
845  switch (Term ? Term->getStmtClass() : Stmt::DeclStmtClass) {
846  default:
847  // Don't know how to report this. Just fall back to 'may be used
848  // uninitialized'. FIXME: Can this happen?
849  continue;
850 
851  // "condition is true / condition is false".
852  case Stmt::IfStmtClass: {
853  const IfStmt *IS = cast<IfStmt>(Term);
854  DiagKind = 0;
855  Str = "if";
856  Range = IS->getCond()->getSourceRange();
857  RemoveDiagKind = 0;
858  CreateIfFixit(S, IS, IS->getThen(), IS->getElse(),
859  I->Output, Fixit1, Fixit2);
860  break;
861  }
862  case Stmt::ConditionalOperatorClass: {
863  const ConditionalOperator *CO = cast<ConditionalOperator>(Term);
864  DiagKind = 0;
865  Str = "?:";
866  Range = CO->getCond()->getSourceRange();
867  RemoveDiagKind = 0;
868  CreateIfFixit(S, CO, CO->getTrueExpr(), CO->getFalseExpr(),
869  I->Output, Fixit1, Fixit2);
870  break;
871  }
872  case Stmt::BinaryOperatorClass: {
873  const BinaryOperator *BO = cast<BinaryOperator>(Term);
874  if (!BO->isLogicalOp())
875  continue;
876  DiagKind = 0;
877  Str = BO->getOpcodeStr();
878  Range = BO->getLHS()->getSourceRange();
879  RemoveDiagKind = 0;
880  if ((BO->getOpcode() == BO_LAnd && I->Output) ||
881  (BO->getOpcode() == BO_LOr && !I->Output))
882  // true && y -> y, false || y -> y.
884  BO->getOperatorLoc()));
885  else
886  // false && y -> false, true || y -> true.
887  Fixit1 = FixItHint::CreateReplacement(BO->getSourceRange(), FixitStr);
888  break;
889  }
890 
891  // "loop is entered / loop is exited".
892  case Stmt::WhileStmtClass:
893  DiagKind = 1;
894  Str = "while";
895  Range = cast<WhileStmt>(Term)->getCond()->getSourceRange();
896  RemoveDiagKind = 1;
897  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
898  break;
899  case Stmt::ForStmtClass:
900  DiagKind = 1;
901  Str = "for";
902  Range = cast<ForStmt>(Term)->getCond()->getSourceRange();
903  RemoveDiagKind = 1;
904  if (I->Output)
905  Fixit1 = FixItHint::CreateRemoval(Range);
906  else
907  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
908  break;
909  case Stmt::CXXForRangeStmtClass:
910  if (I->Output == 1) {
911  // The use occurs if a range-based for loop's body never executes.
912  // That may be impossible, and there's no syntactic fix for this,
913  // so treat it as a 'may be uninitialized' case.
914  continue;
915  }
916  DiagKind = 1;
917  Str = "for";
918  Range = cast<CXXForRangeStmt>(Term)->getRangeInit()->getSourceRange();
919  break;
920 
921  // "condition is true / loop is exited".
922  case Stmt::DoStmtClass:
923  DiagKind = 2;
924  Str = "do";
925  Range = cast<DoStmt>(Term)->getCond()->getSourceRange();
926  RemoveDiagKind = 1;
927  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
928  break;
929 
930  // "switch case is taken".
931  case Stmt::CaseStmtClass:
932  DiagKind = 3;
933  Str = "case";
934  Range = cast<CaseStmt>(Term)->getLHS()->getSourceRange();
935  break;
936  case Stmt::DefaultStmtClass:
937  DiagKind = 3;
938  Str = "default";
939  Range = cast<DefaultStmt>(Term)->getDefaultLoc();
940  break;
941  }
942 
943  S.Diag(Range.getBegin(), diag::warn_sometimes_uninit_var)
944  << VD->getDeclName() << IsCapturedByBlock << DiagKind
945  << Str << I->Output << Range;
946  S.Diag(User->getLocStart(), diag::note_uninit_var_use)
947  << IsCapturedByBlock << User->getSourceRange();
948  if (RemoveDiagKind != -1)
949  S.Diag(Fixit1.RemoveRange.getBegin(), diag::note_uninit_fixit_remove_cond)
950  << RemoveDiagKind << Str << I->Output << Fixit1 << Fixit2;
951 
952  Diagnosed = true;
953  }
954 
955  if (!Diagnosed)
956  S.Diag(Use.getUser()->getLocStart(), diag::warn_maybe_uninit_var)
957  << VD->getDeclName() << IsCapturedByBlock
958  << Use.getUser()->getSourceRange();
959 }
960 
961 /// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
962 /// uninitialized variable. This manages the different forms of diagnostic
963 /// emitted for particular types of uses. Returns true if the use was diagnosed
964 /// as a warning. If a particular use is one we omit warnings for, returns
965 /// false.
966 static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
967  const UninitUse &Use,
968  bool alwaysReportSelfInit = false) {
969  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Use.getUser())) {
970  // Inspect the initializer of the variable declaration which is
971  // being referenced prior to its initialization. We emit
972  // specialized diagnostics for self-initialization, and we
973  // specifically avoid warning about self references which take the
974  // form of:
975  //
976  // int x = x;
977  //
978  // This is used to indicate to GCC that 'x' is intentionally left
979  // uninitialized. Proven code paths which access 'x' in
980  // an uninitialized state after this will still warn.
981  if (const Expr *Initializer = VD->getInit()) {
982  if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
983  return false;
984 
985  ContainsReference CR(S.Context, DRE);
986  CR.Visit(Initializer);
987  if (CR.doesContainReference()) {
988  S.Diag(DRE->getLocStart(),
989  diag::warn_uninit_self_reference_in_init)
990  << VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
991  return true;
992  }
993  }
994 
995  DiagUninitUse(S, VD, Use, false);
996  } else {
997  const BlockExpr *BE = cast<BlockExpr>(Use.getUser());
998  if (VD->getType()->isBlockPointerType() && !VD->hasAttr<BlocksAttr>())
999  S.Diag(BE->getLocStart(),
1000  diag::warn_uninit_byref_blockvar_captured_by_block)
1001  << VD->getDeclName();
1002  else
1003  DiagUninitUse(S, VD, Use, true);
1004  }
1005 
1006  // Report where the variable was declared when the use wasn't within
1007  // the initializer of that declaration & we didn't already suggest
1008  // an initialization fixit.
1009  if (!SuggestInitializationFixit(S, VD))
1010  S.Diag(VD->getLocStart(), diag::note_var_declared_here)
1011  << VD->getDeclName();
1012 
1013  return true;
1014 }
1015 
1016 namespace {
1017  class FallthroughMapper : public RecursiveASTVisitor<FallthroughMapper> {
1018  public:
1019  FallthroughMapper(Sema &S)
1020  : FoundSwitchStatements(false),
1021  S(S) {
1022  }
1023 
1024  bool foundSwitchStatements() const { return FoundSwitchStatements; }
1025 
1026  void markFallthroughVisited(const AttributedStmt *Stmt) {
1027  bool Found = FallthroughStmts.erase(Stmt);
1028  assert(Found);
1029  (void)Found;
1030  }
1031 
1032  typedef llvm::SmallPtrSet<const AttributedStmt*, 8> AttrStmts;
1033 
1034  const AttrStmts &getFallthroughStmts() const {
1035  return FallthroughStmts;
1036  }
1037 
1038  void fillReachableBlocks(CFG *Cfg) {
1039  assert(ReachableBlocks.empty() && "ReachableBlocks already filled");
1040  std::deque<const CFGBlock *> BlockQueue;
1041 
1042  ReachableBlocks.insert(&Cfg->getEntry());
1043  BlockQueue.push_back(&Cfg->getEntry());
1044  // Mark all case blocks reachable to avoid problems with switching on
1045  // constants, covered enums, etc.
1046  // These blocks can contain fall-through annotations, and we don't want to
1047  // issue a warn_fallthrough_attr_unreachable for them.
1048  for (const auto *B : *Cfg) {
1049  const Stmt *L = B->getLabel();
1050  if (L && isa<SwitchCase>(L) && ReachableBlocks.insert(B).second)
1051  BlockQueue.push_back(B);
1052  }
1053 
1054  while (!BlockQueue.empty()) {
1055  const CFGBlock *P = BlockQueue.front();
1056  BlockQueue.pop_front();
1058  E = P->succ_end();
1059  I != E; ++I) {
1060  if (*I && ReachableBlocks.insert(*I).second)
1061  BlockQueue.push_back(*I);
1062  }
1063  }
1064  }
1065 
1066  bool checkFallThroughIntoBlock(const CFGBlock &B, int &AnnotatedCnt,
1067  bool IsTemplateInstantiation) {
1068  assert(!ReachableBlocks.empty() && "ReachableBlocks empty");
1069 
1070  int UnannotatedCnt = 0;
1071  AnnotatedCnt = 0;
1072 
1073  std::deque<const CFGBlock*> BlockQueue(B.pred_begin(), B.pred_end());
1074  while (!BlockQueue.empty()) {
1075  const CFGBlock *P = BlockQueue.front();
1076  BlockQueue.pop_front();
1077  if (!P) continue;
1078 
1079  const Stmt *Term = P->getTerminator();
1080  if (Term && isa<SwitchStmt>(Term))
1081  continue; // Switch statement, good.
1082 
1083  const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(P->getLabel());
1084  if (SW && SW->getSubStmt() == B.getLabel() && P->begin() == P->end())
1085  continue; // Previous case label has no statements, good.
1086 
1087  const LabelStmt *L = dyn_cast_or_null<LabelStmt>(P->getLabel());
1088  if (L && L->getSubStmt() == B.getLabel() && P->begin() == P->end())
1089  continue; // Case label is preceded with a normal label, good.
1090 
1091  if (!ReachableBlocks.count(P)) {
1092  for (CFGBlock::const_reverse_iterator ElemIt = P->rbegin(),
1093  ElemEnd = P->rend();
1094  ElemIt != ElemEnd; ++ElemIt) {
1095  if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>()) {
1096  if (const AttributedStmt *AS = asFallThroughAttr(CS->getStmt())) {
1097  // Don't issue a warning for an unreachable fallthrough
1098  // attribute in template instantiations as it may not be
1099  // unreachable in all instantiations of the template.
1100  if (!IsTemplateInstantiation)
1101  S.Diag(AS->getLocStart(),
1102  diag::warn_fallthrough_attr_unreachable);
1103  markFallthroughVisited(AS);
1104  ++AnnotatedCnt;
1105  break;
1106  }
1107  // Don't care about other unreachable statements.
1108  }
1109  }
1110  // If there are no unreachable statements, this may be a special
1111  // case in CFG:
1112  // case X: {
1113  // A a; // A has a destructor.
1114  // break;
1115  // }
1116  // // <<<< This place is represented by a 'hanging' CFG block.
1117  // case Y:
1118  continue;
1119  }
1120 
1121  const Stmt *LastStmt = getLastStmt(*P);
1122  if (const AttributedStmt *AS = asFallThroughAttr(LastStmt)) {
1123  markFallthroughVisited(AS);
1124  ++AnnotatedCnt;
1125  continue; // Fallthrough annotation, good.
1126  }
1127 
1128  if (!LastStmt) { // This block contains no executable statements.
1129  // Traverse its predecessors.
1130  std::copy(P->pred_begin(), P->pred_end(),
1131  std::back_inserter(BlockQueue));
1132  continue;
1133  }
1134 
1135  ++UnannotatedCnt;
1136  }
1137  return !!UnannotatedCnt;
1138  }
1139 
1140  // RecursiveASTVisitor setup.
1141  bool shouldWalkTypesOfTypeLocs() const { return false; }
1142 
1143  bool VisitAttributedStmt(AttributedStmt *S) {
1144  if (asFallThroughAttr(S))
1145  FallthroughStmts.insert(S);
1146  return true;
1147  }
1148 
1149  bool VisitSwitchStmt(SwitchStmt *S) {
1150  FoundSwitchStatements = true;
1151  return true;
1152  }
1153 
1154  // We don't want to traverse local type declarations. We analyze their
1155  // methods separately.
1156  bool TraverseDecl(Decl *D) { return true; }
1157 
1158  // We analyze lambda bodies separately. Skip them here.
1159  bool TraverseLambdaBody(LambdaExpr *LE) { return true; }
1160 
1161  private:
1162 
1163  static const AttributedStmt *asFallThroughAttr(const Stmt *S) {
1164  if (const AttributedStmt *AS = dyn_cast_or_null<AttributedStmt>(S)) {
1165  if (hasSpecificAttr<FallThroughAttr>(AS->getAttrs()))
1166  return AS;
1167  }
1168  return nullptr;
1169  }
1170 
1171  static const Stmt *getLastStmt(const CFGBlock &B) {
1172  if (const Stmt *Term = B.getTerminator())
1173  return Term;
1174  for (CFGBlock::const_reverse_iterator ElemIt = B.rbegin(),
1175  ElemEnd = B.rend();
1176  ElemIt != ElemEnd; ++ElemIt) {
1177  if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>())
1178  return CS->getStmt();
1179  }
1180  // Workaround to detect a statement thrown out by CFGBuilder:
1181  // case X: {} case Y:
1182  // case X: ; case Y:
1183  if (const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(B.getLabel()))
1184  if (!isa<SwitchCase>(SW->getSubStmt()))
1185  return SW->getSubStmt();
1186 
1187  return nullptr;
1188  }
1189 
1190  bool FoundSwitchStatements;
1191  AttrStmts FallthroughStmts;
1192  Sema &S;
1193  llvm::SmallPtrSet<const CFGBlock *, 16> ReachableBlocks;
1194  };
1195 } // anonymous namespace
1196 
1198  SourceLocation Loc) {
1199  TokenValue FallthroughTokens[] = {
1200  tok::l_square, tok::l_square,
1201  PP.getIdentifierInfo("fallthrough"),
1202  tok::r_square, tok::r_square
1203  };
1204 
1205  TokenValue ClangFallthroughTokens[] = {
1206  tok::l_square, tok::l_square, PP.getIdentifierInfo("clang"),
1207  tok::coloncolon, PP.getIdentifierInfo("fallthrough"),
1208  tok::r_square, tok::r_square
1209  };
1210 
1211  bool PreferClangAttr = !PP.getLangOpts().CPlusPlus17;
1212 
1213  StringRef MacroName;
1214  if (PreferClangAttr)
1215  MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
1216  if (MacroName.empty())
1217  MacroName = PP.getLastMacroWithSpelling(Loc, FallthroughTokens);
1218  if (MacroName.empty() && !PreferClangAttr)
1219  MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
1220  if (MacroName.empty())
1221  MacroName = PreferClangAttr ? "[[clang::fallthrough]]" : "[[fallthrough]]";
1222  return MacroName;
1223 }
1224 
1226  bool PerFunction) {
1227  // Only perform this analysis when using [[]] attributes. There is no good
1228  // workflow for this warning when not using C++11. There is no good way to
1229  // silence the warning (no attribute is available) unless we are using
1230  // [[]] attributes. One could use pragmas to silence the warning, but as a
1231  // general solution that is gross and not in the spirit of this warning.
1232  //
1233  // NOTE: This an intermediate solution. There are on-going discussions on
1234  // how to properly support this warning outside of C++11 with an annotation.
1235  if (!AC.getASTContext().getLangOpts().DoubleSquareBracketAttributes)
1236  return;
1237 
1238  FallthroughMapper FM(S);
1239  FM.TraverseStmt(AC.getBody());
1240 
1241  if (!FM.foundSwitchStatements())
1242  return;
1243 
1244  if (PerFunction && FM.getFallthroughStmts().empty())
1245  return;
1246 
1247  CFG *Cfg = AC.getCFG();
1248 
1249  if (!Cfg)
1250  return;
1251 
1252  FM.fillReachableBlocks(Cfg);
1253 
1254  for (const CFGBlock *B : llvm::reverse(*Cfg)) {
1255  const Stmt *Label = B->getLabel();
1256 
1257  if (!Label || !isa<SwitchCase>(Label))
1258  continue;
1259 
1260  int AnnotatedCnt;
1261 
1262  bool IsTemplateInstantiation = false;
1263  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(AC.getDecl()))
1264  IsTemplateInstantiation = Function->isTemplateInstantiation();
1265  if (!FM.checkFallThroughIntoBlock(*B, AnnotatedCnt,
1266  IsTemplateInstantiation))
1267  continue;
1268 
1269  S.Diag(Label->getLocStart(),
1270  PerFunction ? diag::warn_unannotated_fallthrough_per_function
1271  : diag::warn_unannotated_fallthrough);
1272 
1273  if (!AnnotatedCnt) {
1274  SourceLocation L = Label->getLocStart();
1275  if (L.isMacroID())
1276  continue;
1277  if (S.getLangOpts().CPlusPlus11) {
1278  const Stmt *Term = B->getTerminator();
1279  // Skip empty cases.
1280  while (B->empty() && !Term && B->succ_size() == 1) {
1281  B = *B->succ_begin();
1282  Term = B->getTerminator();
1283  }
1284  if (!(B->empty() && Term && isa<BreakStmt>(Term))) {
1285  Preprocessor &PP = S.getPreprocessor();
1286  StringRef AnnotationSpelling = getFallthroughAttrSpelling(PP, L);
1287  SmallString<64> TextToInsert(AnnotationSpelling);
1288  TextToInsert += "; ";
1289  S.Diag(L, diag::note_insert_fallthrough_fixit) <<
1290  AnnotationSpelling <<
1291  FixItHint::CreateInsertion(L, TextToInsert);
1292  }
1293  }
1294  S.Diag(L, diag::note_insert_break_fixit) <<
1295  FixItHint::CreateInsertion(L, "break; ");
1296  }
1297  }
1298 
1299  for (const auto *F : FM.getFallthroughStmts())
1300  S.Diag(F->getLocStart(), diag::err_fallthrough_attr_invalid_placement);
1301 }
1302 
1303 static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM,
1304  const Stmt *S) {
1305  assert(S);
1306 
1307  do {
1308  switch (S->getStmtClass()) {
1309  case Stmt::ForStmtClass:
1310  case Stmt::WhileStmtClass:
1311  case Stmt::CXXForRangeStmtClass:
1312  case Stmt::ObjCForCollectionStmtClass:
1313  return true;
1314  case Stmt::DoStmtClass: {
1315  const Expr *Cond = cast<DoStmt>(S)->getCond();
1316  llvm::APSInt Val;
1317  if (!Cond->EvaluateAsInt(Val, Ctx))
1318  return true;
1319  return Val.getBoolValue();
1320  }
1321  default:
1322  break;
1323  }
1324  } while ((S = PM.getParent(S)));
1325 
1326  return false;
1327 }
1328 
1330  const sema::FunctionScopeInfo *CurFn,
1331  const Decl *D,
1332  const ParentMap &PM) {
1333  typedef sema::FunctionScopeInfo::WeakObjectProfileTy WeakObjectProfileTy;
1334  typedef sema::FunctionScopeInfo::WeakObjectUseMap WeakObjectUseMap;
1335  typedef sema::FunctionScopeInfo::WeakUseVector WeakUseVector;
1336  typedef std::pair<const Stmt *, WeakObjectUseMap::const_iterator>
1337  StmtUsesPair;
1338 
1339  ASTContext &Ctx = S.getASTContext();
1340 
1341  const WeakObjectUseMap &WeakMap = CurFn->getWeakObjectUses();
1342 
1343  // Extract all weak objects that are referenced more than once.
1344  SmallVector<StmtUsesPair, 8> UsesByStmt;
1345  for (WeakObjectUseMap::const_iterator I = WeakMap.begin(), E = WeakMap.end();
1346  I != E; ++I) {
1347  const WeakUseVector &Uses = I->second;
1348 
1349  // Find the first read of the weak object.
1350  WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
1351  for ( ; UI != UE; ++UI) {
1352  if (UI->isUnsafe())
1353  break;
1354  }
1355 
1356  // If there were only writes to this object, don't warn.
1357  if (UI == UE)
1358  continue;
1359 
1360  // If there was only one read, followed by any number of writes, and the
1361  // read is not within a loop, don't warn. Additionally, don't warn in a
1362  // loop if the base object is a local variable -- local variables are often
1363  // changed in loops.
1364  if (UI == Uses.begin()) {
1365  WeakUseVector::const_iterator UI2 = UI;
1366  for (++UI2; UI2 != UE; ++UI2)
1367  if (UI2->isUnsafe())
1368  break;
1369 
1370  if (UI2 == UE) {
1371  if (!isInLoop(Ctx, PM, UI->getUseExpr()))
1372  continue;
1373 
1374  const WeakObjectProfileTy &Profile = I->first;
1375  if (!Profile.isExactProfile())
1376  continue;
1377 
1378  const NamedDecl *Base = Profile.getBase();
1379  if (!Base)
1380  Base = Profile.getProperty();
1381  assert(Base && "A profile always has a base or property.");
1382 
1383  if (const VarDecl *BaseVar = dyn_cast<VarDecl>(Base))
1384  if (BaseVar->hasLocalStorage() && !isa<ParmVarDecl>(Base))
1385  continue;
1386  }
1387  }
1388 
1389  UsesByStmt.push_back(StmtUsesPair(UI->getUseExpr(), I));
1390  }
1391 
1392  if (UsesByStmt.empty())
1393  return;
1394 
1395  // Sort by first use so that we emit the warnings in a deterministic order.
1397  llvm::sort(UsesByStmt.begin(), UsesByStmt.end(),
1398  [&SM](const StmtUsesPair &LHS, const StmtUsesPair &RHS) {
1399  return SM.isBeforeInTranslationUnit(LHS.first->getLocStart(),
1400  RHS.first->getLocStart());
1401  });
1402 
1403  // Classify the current code body for better warning text.
1404  // This enum should stay in sync with the cases in
1405  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1406  // FIXME: Should we use a common classification enum and the same set of
1407  // possibilities all throughout Sema?
1408  enum {
1409  Function,
1410  Method,
1411  Block,
1412  Lambda
1413  } FunctionKind;
1414 
1415  if (isa<sema::BlockScopeInfo>(CurFn))
1416  FunctionKind = Block;
1417  else if (isa<sema::LambdaScopeInfo>(CurFn))
1418  FunctionKind = Lambda;
1419  else if (isa<ObjCMethodDecl>(D))
1420  FunctionKind = Method;
1421  else
1422  FunctionKind = Function;
1423 
1424  // Iterate through the sorted problems and emit warnings for each.
1425  for (const auto &P : UsesByStmt) {
1426  const Stmt *FirstRead = P.first;
1427  const WeakObjectProfileTy &Key = P.second->first;
1428  const WeakUseVector &Uses = P.second->second;
1429 
1430  // For complicated expressions like 'a.b.c' and 'x.b.c', WeakObjectProfileTy
1431  // may not contain enough information to determine that these are different
1432  // properties. We can only be 100% sure of a repeated use in certain cases,
1433  // and we adjust the diagnostic kind accordingly so that the less certain
1434  // case can be turned off if it is too noisy.
1435  unsigned DiagKind;
1436  if (Key.isExactProfile())
1437  DiagKind = diag::warn_arc_repeated_use_of_weak;
1438  else
1439  DiagKind = diag::warn_arc_possible_repeated_use_of_weak;
1440 
1441  // Classify the weak object being accessed for better warning text.
1442  // This enum should stay in sync with the cases in
1443  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1444  enum {
1445  Variable,
1446  Property,
1447  ImplicitProperty,
1448  Ivar
1449  } ObjectKind;
1450 
1451  const NamedDecl *KeyProp = Key.getProperty();
1452  if (isa<VarDecl>(KeyProp))
1453  ObjectKind = Variable;
1454  else if (isa<ObjCPropertyDecl>(KeyProp))
1455  ObjectKind = Property;
1456  else if (isa<ObjCMethodDecl>(KeyProp))
1457  ObjectKind = ImplicitProperty;
1458  else if (isa<ObjCIvarDecl>(KeyProp))
1459  ObjectKind = Ivar;
1460  else
1461  llvm_unreachable("Unexpected weak object kind!");
1462 
1463  // Do not warn about IBOutlet weak property receivers being set to null
1464  // since they are typically only used from the main thread.
1465  if (const ObjCPropertyDecl *Prop = dyn_cast<ObjCPropertyDecl>(KeyProp))
1466  if (Prop->hasAttr<IBOutletAttr>())
1467  continue;
1468 
1469  // Show the first time the object was read.
1470  S.Diag(FirstRead->getLocStart(), DiagKind)
1471  << int(ObjectKind) << KeyProp << int(FunctionKind)
1472  << FirstRead->getSourceRange();
1473 
1474  // Print all the other accesses as notes.
1475  for (const auto &Use : Uses) {
1476  if (Use.getUseExpr() == FirstRead)
1477  continue;
1478  S.Diag(Use.getUseExpr()->getLocStart(),
1479  diag::note_arc_weak_also_accessed_here)
1480  << Use.getUseExpr()->getSourceRange();
1481  }
1482  }
1483 }
1484 
1485 namespace {
1486 class UninitValsDiagReporter : public UninitVariablesHandler {
1487  Sema &S;
1488  typedef SmallVector<UninitUse, 2> UsesVec;
1489  typedef llvm::PointerIntPair<UsesVec *, 1, bool> MappedType;
1490  // Prefer using MapVector to DenseMap, so that iteration order will be
1491  // the same as insertion order. This is needed to obtain a deterministic
1492  // order of diagnostics when calling flushDiagnostics().
1493  typedef llvm::MapVector<const VarDecl *, MappedType> UsesMap;
1494  UsesMap uses;
1495 
1496 public:
1497  UninitValsDiagReporter(Sema &S) : S(S) {}
1498  ~UninitValsDiagReporter() override { flushDiagnostics(); }
1499 
1500  MappedType &getUses(const VarDecl *vd) {
1501  MappedType &V = uses[vd];
1502  if (!V.getPointer())
1503  V.setPointer(new UsesVec());
1504  return V;
1505  }
1506 
1507  void handleUseOfUninitVariable(const VarDecl *vd,
1508  const UninitUse &use) override {
1509  getUses(vd).getPointer()->push_back(use);
1510  }
1511 
1512  void handleSelfInit(const VarDecl *vd) override {
1513  getUses(vd).setInt(true);
1514  }
1515 
1516  void flushDiagnostics() {
1517  for (const auto &P : uses) {
1518  const VarDecl *vd = P.first;
1519  const MappedType &V = P.second;
1520 
1521  UsesVec *vec = V.getPointer();
1522  bool hasSelfInit = V.getInt();
1523 
1524  // Specially handle the case where we have uses of an uninitialized
1525  // variable, but the root cause is an idiomatic self-init. We want
1526  // to report the diagnostic at the self-init since that is the root cause.
1527  if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
1530  /* isAlwaysUninit */ true),
1531  /* alwaysReportSelfInit */ true);
1532  else {
1533  // Sort the uses by their SourceLocations. While not strictly
1534  // guaranteed to produce them in line/column order, this will provide
1535  // a stable ordering.
1536  llvm::sort(vec->begin(), vec->end(),
1537  [](const UninitUse &a, const UninitUse &b) {
1538  // Prefer a more confident report over a less confident one.
1539  if (a.getKind() != b.getKind())
1540  return a.getKind() > b.getKind();
1541  return a.getUser()->getLocStart() < b.getUser()->getLocStart();
1542  });
1543 
1544  for (const auto &U : *vec) {
1545  // If we have self-init, downgrade all uses to 'may be uninitialized'.
1546  UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
1547 
1548  if (DiagnoseUninitializedUse(S, vd, Use))
1549  // Skip further diagnostics for this variable. We try to warn only
1550  // on the first point at which a variable is used uninitialized.
1551  break;
1552  }
1553  }
1554 
1555  // Release the uses vector.
1556  delete vec;
1557  }
1558 
1559  uses.clear();
1560  }
1561 
1562 private:
1563  static bool hasAlwaysUninitializedUse(const UsesVec* vec) {
1564  return std::any_of(vec->begin(), vec->end(), [](const UninitUse &U) {
1565  return U.getKind() == UninitUse::Always ||
1566  U.getKind() == UninitUse::AfterCall ||
1567  U.getKind() == UninitUse::AfterDecl;
1568  });
1569  }
1570 };
1571 } // anonymous namespace
1572 
1573 namespace clang {
1574 namespace {
1576 typedef std::pair<PartialDiagnosticAt, OptionalNotes> DelayedDiag;
1577 typedef std::list<DelayedDiag> DiagList;
1578 
1579 struct SortDiagBySourceLocation {
1581  SortDiagBySourceLocation(SourceManager &SM) : SM(SM) {}
1582 
1583  bool operator()(const DelayedDiag &left, const DelayedDiag &right) {
1584  // Although this call will be slow, this is only called when outputting
1585  // multiple warnings.
1586  return SM.isBeforeInTranslationUnit(left.first.first, right.first.first);
1587  }
1588 };
1589 } // anonymous namespace
1590 } // namespace clang
1591 
1592 //===----------------------------------------------------------------------===//
1593 // -Wthread-safety
1594 //===----------------------------------------------------------------------===//
1595 namespace clang {
1596 namespace threadSafety {
1597 namespace {
1598 class ThreadSafetyReporter : public clang::threadSafety::ThreadSafetyHandler {
1599  Sema &S;
1600  DiagList Warnings;
1601  SourceLocation FunLocation, FunEndLocation;
1602 
1603  const FunctionDecl *CurrentFunction;
1604  bool Verbose;
1605 
1606  OptionalNotes getNotes() const {
1607  if (Verbose && CurrentFunction) {
1608  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getLocStart(),
1609  S.PDiag(diag::note_thread_warning_in_fun)
1610  << CurrentFunction);
1611  return OptionalNotes(1, FNote);
1612  }
1613  return OptionalNotes();
1614  }
1615 
1616  OptionalNotes getNotes(const PartialDiagnosticAt &Note) const {
1617  OptionalNotes ONS(1, Note);
1618  if (Verbose && CurrentFunction) {
1619  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getLocStart(),
1620  S.PDiag(diag::note_thread_warning_in_fun)
1621  << CurrentFunction);
1622  ONS.push_back(std::move(FNote));
1623  }
1624  return ONS;
1625  }
1626 
1627  OptionalNotes getNotes(const PartialDiagnosticAt &Note1,
1628  const PartialDiagnosticAt &Note2) const {
1629  OptionalNotes ONS;
1630  ONS.push_back(Note1);
1631  ONS.push_back(Note2);
1632  if (Verbose && CurrentFunction) {
1633  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getLocStart(),
1634  S.PDiag(diag::note_thread_warning_in_fun)
1635  << CurrentFunction);
1636  ONS.push_back(std::move(FNote));
1637  }
1638  return ONS;
1639  }
1640 
1641  // Helper functions
1642  void warnLockMismatch(unsigned DiagID, StringRef Kind, Name LockName,
1643  SourceLocation Loc) {
1644  // Gracefully handle rare cases when the analysis can't get a more
1645  // precise source location.
1646  if (!Loc.isValid())
1647  Loc = FunLocation;
1648  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind << LockName);
1649  Warnings.emplace_back(std::move(Warning), getNotes());
1650  }
1651 
1652  public:
1653  ThreadSafetyReporter(Sema &S, SourceLocation FL, SourceLocation FEL)
1654  : S(S), FunLocation(FL), FunEndLocation(FEL),
1655  CurrentFunction(nullptr), Verbose(false) {}
1656 
1657  void setVerbose(bool b) { Verbose = b; }
1658 
1659  /// Emit all buffered diagnostics in order of sourcelocation.
1660  /// We need to output diagnostics produced while iterating through
1661  /// the lockset in deterministic order, so this function orders diagnostics
1662  /// and outputs them.
1663  void emitDiagnostics() {
1664  Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1665  for (const auto &Diag : Warnings) {
1666  S.Diag(Diag.first.first, Diag.first.second);
1667  for (const auto &Note : Diag.second)
1668  S.Diag(Note.first, Note.second);
1669  }
1670  }
1671 
1672  void handleInvalidLockExp(StringRef Kind, SourceLocation Loc) override {
1673  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_cannot_resolve_lock)
1674  << Loc);
1675  Warnings.emplace_back(std::move(Warning), getNotes());
1676  }
1677 
1678  void handleUnmatchedUnlock(StringRef Kind, Name LockName,
1679  SourceLocation Loc) override {
1680  warnLockMismatch(diag::warn_unlock_but_no_lock, Kind, LockName, Loc);
1681  }
1682 
1683  void handleIncorrectUnlockKind(StringRef Kind, Name LockName,
1684  LockKind Expected, LockKind Received,
1685  SourceLocation Loc) override {
1686  if (Loc.isInvalid())
1687  Loc = FunLocation;
1688  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_unlock_kind_mismatch)
1689  << Kind << LockName << Received
1690  << Expected);
1691  Warnings.emplace_back(std::move(Warning), getNotes());
1692  }
1693 
1694  void handleDoubleLock(StringRef Kind, Name LockName, SourceLocation Loc) override {
1695  warnLockMismatch(diag::warn_double_lock, Kind, LockName, Loc);
1696  }
1697 
1698  void handleMutexHeldEndOfScope(StringRef Kind, Name LockName,
1699  SourceLocation LocLocked,
1700  SourceLocation LocEndOfScope,
1701  LockErrorKind LEK) override {
1702  unsigned DiagID = 0;
1703  switch (LEK) {
1705  DiagID = diag::warn_lock_some_predecessors;
1706  break;
1708  DiagID = diag::warn_expecting_lock_held_on_loop;
1709  break;
1711  DiagID = diag::warn_no_unlock;
1712  break;
1714  DiagID = diag::warn_expecting_locked;
1715  break;
1716  }
1717  if (LocEndOfScope.isInvalid())
1718  LocEndOfScope = FunEndLocation;
1719 
1720  PartialDiagnosticAt Warning(LocEndOfScope, S.PDiag(DiagID) << Kind
1721  << LockName);
1722  if (LocLocked.isValid()) {
1723  PartialDiagnosticAt Note(LocLocked, S.PDiag(diag::note_locked_here)
1724  << Kind);
1725  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1726  return;
1727  }
1728  Warnings.emplace_back(std::move(Warning), getNotes());
1729  }
1730 
1731  void handleExclusiveAndShared(StringRef Kind, Name LockName,
1732  SourceLocation Loc1,
1733  SourceLocation Loc2) override {
1735  S.PDiag(diag::warn_lock_exclusive_and_shared)
1736  << Kind << LockName);
1737  PartialDiagnosticAt Note(Loc2, S.PDiag(diag::note_lock_exclusive_and_shared)
1738  << Kind << LockName);
1739  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1740  }
1741 
1742  void handleNoMutexHeld(StringRef Kind, const NamedDecl *D,
1744  SourceLocation Loc) override {
1745  assert((POK == POK_VarAccess || POK == POK_VarDereference) &&
1746  "Only works for variables");
1747  unsigned DiagID = POK == POK_VarAccess?
1748  diag::warn_variable_requires_any_lock:
1749  diag::warn_var_deref_requires_any_lock;
1750  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
1751  << D << getLockKindFromAccessKind(AK));
1752  Warnings.emplace_back(std::move(Warning), getNotes());
1753  }
1754 
1755  void handleMutexNotHeld(StringRef Kind, const NamedDecl *D,
1756  ProtectedOperationKind POK, Name LockName,
1757  LockKind LK, SourceLocation Loc,
1758  Name *PossibleMatch) override {
1759  unsigned DiagID = 0;
1760  if (PossibleMatch) {
1761  switch (POK) {
1762  case POK_VarAccess:
1763  DiagID = diag::warn_variable_requires_lock_precise;
1764  break;
1765  case POK_VarDereference:
1766  DiagID = diag::warn_var_deref_requires_lock_precise;
1767  break;
1768  case POK_FunctionCall:
1769  DiagID = diag::warn_fun_requires_lock_precise;
1770  break;
1771  case POK_PassByRef:
1772  DiagID = diag::warn_guarded_pass_by_reference;
1773  break;
1774  case POK_PtPassByRef:
1775  DiagID = diag::warn_pt_guarded_pass_by_reference;
1776  break;
1777  }
1778  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
1779  << D
1780  << LockName << LK);
1781  PartialDiagnosticAt Note(Loc, S.PDiag(diag::note_found_mutex_near_match)
1782  << *PossibleMatch);
1783  if (Verbose && POK == POK_VarAccess) {
1784  PartialDiagnosticAt VNote(D->getLocation(),
1785  S.PDiag(diag::note_guarded_by_declared_here)
1786  << D->getNameAsString());
1787  Warnings.emplace_back(std::move(Warning), getNotes(Note, VNote));
1788  } else
1789  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1790  } else {
1791  switch (POK) {
1792  case POK_VarAccess:
1793  DiagID = diag::warn_variable_requires_lock;
1794  break;
1795  case POK_VarDereference:
1796  DiagID = diag::warn_var_deref_requires_lock;
1797  break;
1798  case POK_FunctionCall:
1799  DiagID = diag::warn_fun_requires_lock;
1800  break;
1801  case POK_PassByRef:
1802  DiagID = diag::warn_guarded_pass_by_reference;
1803  break;
1804  case POK_PtPassByRef:
1805  DiagID = diag::warn_pt_guarded_pass_by_reference;
1806  break;
1807  }
1808  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
1809  << D
1810  << LockName << LK);
1811  if (Verbose && POK == POK_VarAccess) {
1813  S.PDiag(diag::note_guarded_by_declared_here));
1814  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1815  } else
1816  Warnings.emplace_back(std::move(Warning), getNotes());
1817  }
1818  }
1819 
1820  void handleNegativeNotHeld(StringRef Kind, Name LockName, Name Neg,
1821  SourceLocation Loc) override {
1823  S.PDiag(diag::warn_acquire_requires_negative_cap)
1824  << Kind << LockName << Neg);
1825  Warnings.emplace_back(std::move(Warning), getNotes());
1826  }
1827 
1828  void handleFunExcludesLock(StringRef Kind, Name FunName, Name LockName,
1829  SourceLocation Loc) override {
1830  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_fun_excludes_mutex)
1831  << Kind << FunName << LockName);
1832  Warnings.emplace_back(std::move(Warning), getNotes());
1833  }
1834 
1835  void handleLockAcquiredBefore(StringRef Kind, Name L1Name, Name L2Name,
1836  SourceLocation Loc) override {
1838  S.PDiag(diag::warn_acquired_before) << Kind << L1Name << L2Name);
1839  Warnings.emplace_back(std::move(Warning), getNotes());
1840  }
1841 
1842  void handleBeforeAfterCycle(Name L1Name, SourceLocation Loc) override {
1844  S.PDiag(diag::warn_acquired_before_after_cycle) << L1Name);
1845  Warnings.emplace_back(std::move(Warning), getNotes());
1846  }
1847 
1848  void enterFunction(const FunctionDecl* FD) override {
1849  CurrentFunction = FD;
1850  }
1851 
1852  void leaveFunction(const FunctionDecl* FD) override {
1853  CurrentFunction = nullptr;
1854  }
1855 };
1856 } // anonymous namespace
1857 } // namespace threadSafety
1858 } // namespace clang
1859 
1860 //===----------------------------------------------------------------------===//
1861 // -Wconsumed
1862 //===----------------------------------------------------------------------===//
1863 
1864 namespace clang {
1865 namespace consumed {
1866 namespace {
1867 class ConsumedWarningsHandler : public ConsumedWarningsHandlerBase {
1868 
1869  Sema &S;
1870  DiagList Warnings;
1871 
1872 public:
1873 
1874  ConsumedWarningsHandler(Sema &S) : S(S) {}
1875 
1876  void emitDiagnostics() override {
1877  Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1878  for (const auto &Diag : Warnings) {
1879  S.Diag(Diag.first.first, Diag.first.second);
1880  for (const auto &Note : Diag.second)
1881  S.Diag(Note.first, Note.second);
1882  }
1883  }
1884 
1885  void warnLoopStateMismatch(SourceLocation Loc,
1886  StringRef VariableName) override {
1887  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_loop_state_mismatch) <<
1888  VariableName);
1889 
1890  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1891  }
1892 
1893  void warnParamReturnTypestateMismatch(SourceLocation Loc,
1894  StringRef VariableName,
1895  StringRef ExpectedState,
1896  StringRef ObservedState) override {
1897 
1899  diag::warn_param_return_typestate_mismatch) << VariableName <<
1900  ExpectedState << ObservedState);
1901 
1902  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1903  }
1904 
1905  void warnParamTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
1906  StringRef ObservedState) override {
1907 
1909  diag::warn_param_typestate_mismatch) << ExpectedState << ObservedState);
1910 
1911  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1912  }
1913 
1914  void warnReturnTypestateForUnconsumableType(SourceLocation Loc,
1915  StringRef TypeName) override {
1917  diag::warn_return_typestate_for_unconsumable_type) << TypeName);
1918 
1919  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1920  }
1921 
1922  void warnReturnTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
1923  StringRef ObservedState) override {
1924 
1926  diag::warn_return_typestate_mismatch) << ExpectedState << ObservedState);
1927 
1928  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1929  }
1930 
1931  void warnUseOfTempInInvalidState(StringRef MethodName, StringRef State,
1932  SourceLocation Loc) override {
1933 
1935  diag::warn_use_of_temp_in_invalid_state) << MethodName << State);
1936 
1937  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1938  }
1939 
1940  void warnUseInInvalidState(StringRef MethodName, StringRef VariableName,
1941  StringRef State, SourceLocation Loc) override {
1942 
1943  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_use_in_invalid_state) <<
1944  MethodName << VariableName << State);
1945 
1946  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1947  }
1948 };
1949 } // anonymous namespace
1950 } // namespace consumed
1951 } // namespace clang
1952 
1953 //===----------------------------------------------------------------------===//
1954 // AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
1955 // warnings on a function, method, or block.
1956 //===----------------------------------------------------------------------===//
1957 
1959  enableCheckFallThrough = 1;
1960  enableCheckUnreachable = 0;
1961  enableThreadSafetyAnalysis = 0;
1962  enableConsumedAnalysis = 0;
1963 }
1964 
1965 static unsigned isEnabled(DiagnosticsEngine &D, unsigned diag) {
1966  return (unsigned)!D.isIgnored(diag, SourceLocation());
1967 }
1968 
1970  : S(s),
1971  NumFunctionsAnalyzed(0),
1972  NumFunctionsWithBadCFGs(0),
1973  NumCFGBlocks(0),
1974  MaxCFGBlocksPerFunction(0),
1975  NumUninitAnalysisFunctions(0),
1976  NumUninitAnalysisVariables(0),
1977  MaxUninitAnalysisVariablesPerFunction(0),
1978  NumUninitAnalysisBlockVisits(0),
1979  MaxUninitAnalysisBlockVisitsPerFunction(0) {
1980 
1981  using namespace diag;
1983 
1984  DefaultPolicy.enableCheckUnreachable =
1985  isEnabled(D, warn_unreachable) ||
1986  isEnabled(D, warn_unreachable_break) ||
1987  isEnabled(D, warn_unreachable_return) ||
1988  isEnabled(D, warn_unreachable_loop_increment);
1989 
1990  DefaultPolicy.enableThreadSafetyAnalysis =
1991  isEnabled(D, warn_double_lock);
1992 
1993  DefaultPolicy.enableConsumedAnalysis =
1994  isEnabled(D, warn_use_in_invalid_state);
1995 }
1996 
1997 static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope) {
1998  for (const auto &D : fscope->PossiblyUnreachableDiags)
1999  S.Diag(D.Loc, D.PD);
2000 }
2001 
2002 void clang::sema::
2004  sema::FunctionScopeInfo *fscope,
2005  const Decl *D, const BlockExpr *blkExpr) {
2006 
2007  // We avoid doing analysis-based warnings when there are errors for
2008  // two reasons:
2009  // (1) The CFGs often can't be constructed (if the body is invalid), so
2010  // don't bother trying.
2011  // (2) The code already has problems; running the analysis just takes more
2012  // time.
2013  DiagnosticsEngine &Diags = S.getDiagnostics();
2014 
2015  // Do not do any analysis if we are going to just ignore them.
2016  if (Diags.getIgnoreAllWarnings() ||
2017  (Diags.getSuppressSystemWarnings() &&
2019  return;
2020 
2021  // For code in dependent contexts, we'll do this at instantiation time.
2022  if (cast<DeclContext>(D)->isDependentContext())
2023  return;
2024 
2025  if (Diags.hasUncompilableErrorOccurred()) {
2026  // Flush out any possibly unreachable diagnostics.
2027  flushDiagnostics(S, fscope);
2028  return;
2029  }
2030 
2031  const Stmt *Body = D->getBody();
2032  assert(Body);
2033 
2034  // Construct the analysis context with the specified CFG build options.
2035  AnalysisDeclContext AC(/* AnalysisDeclContextManager */ nullptr, D);
2036 
2037  // Don't generate EH edges for CallExprs as we'd like to avoid the n^2
2038  // explosion for destructors that can result and the compile time hit.
2040  AC.getCFGBuildOptions().AddEHEdges = false;
2041  AC.getCFGBuildOptions().AddInitializers = true;
2046 
2047  // Force that certain expressions appear as CFGElements in the CFG. This
2048  // is used to speed up various analyses.
2049  // FIXME: This isn't the right factoring. This is here for initial
2050  // prototyping, but we need a way for analyses to say what expressions they
2051  // expect to always be CFGElements and then fill in the BuildOptions
2052  // appropriately. This is essentially a layering violation.
2053  if (P.enableCheckUnreachable || P.enableThreadSafetyAnalysis ||
2054  P.enableConsumedAnalysis) {
2055  // Unreachable code analysis and thread safety require a linearized CFG.
2057  }
2058  else {
2059  AC.getCFGBuildOptions()
2060  .setAlwaysAdd(Stmt::BinaryOperatorClass)
2061  .setAlwaysAdd(Stmt::CompoundAssignOperatorClass)
2062  .setAlwaysAdd(Stmt::BlockExprClass)
2063  .setAlwaysAdd(Stmt::CStyleCastExprClass)
2064  .setAlwaysAdd(Stmt::DeclRefExprClass)
2065  .setAlwaysAdd(Stmt::ImplicitCastExprClass)
2066  .setAlwaysAdd(Stmt::UnaryOperatorClass)
2067  .setAlwaysAdd(Stmt::AttributedStmtClass);
2068  }
2069 
2070  // Install the logical handler for -Wtautological-overlap-compare
2071  std::unique_ptr<LogicalErrorHandler> LEH;
2072  if (!Diags.isIgnored(diag::warn_tautological_overlap_comparison,
2073  D->getLocStart())) {
2074  LEH.reset(new LogicalErrorHandler(S));
2075  AC.getCFGBuildOptions().Observer = LEH.get();
2076  }
2077 
2078  // Emit delayed diagnostics.
2079  if (!fscope->PossiblyUnreachableDiags.empty()) {
2080  bool analyzed = false;
2081 
2082  // Register the expressions with the CFGBuilder.
2083  for (const auto &D : fscope->PossiblyUnreachableDiags) {
2084  if (D.stmt)
2085  AC.registerForcedBlockExpression(D.stmt);
2086  }
2087 
2088  if (AC.getCFG()) {
2089  analyzed = true;
2090  for (const auto &D : fscope->PossiblyUnreachableDiags) {
2091  bool processed = false;
2092  if (D.stmt) {
2093  const CFGBlock *block = AC.getBlockForRegisteredExpression(D.stmt);
2096  // FIXME: We should be able to assert that block is non-null, but
2097  // the CFG analysis can skip potentially-evaluated expressions in
2098  // edge cases; see test/Sema/vla-2.c.
2099  if (block && cra) {
2100  // Can this block be reached from the entrance?
2101  if (cra->isReachable(&AC.getCFG()->getEntry(), block))
2102  S.Diag(D.Loc, D.PD);
2103  processed = true;
2104  }
2105  }
2106  if (!processed) {
2107  // Emit the warning anyway if we cannot map to a basic block.
2108  S.Diag(D.Loc, D.PD);
2109  }
2110  }
2111  }
2112 
2113  if (!analyzed)
2114  flushDiagnostics(S, fscope);
2115  }
2116 
2117  // Warning: check missing 'return'
2118  if (P.enableCheckFallThrough) {
2119  const CheckFallThroughDiagnostics &CD =
2120  (isa<BlockDecl>(D)
2121  ? CheckFallThroughDiagnostics::MakeForBlock()
2122  : (isa<CXXMethodDecl>(D) &&
2123  cast<CXXMethodDecl>(D)->getOverloadedOperator() == OO_Call &&
2124  cast<CXXMethodDecl>(D)->getParent()->isLambda())
2125  ? CheckFallThroughDiagnostics::MakeForLambda()
2126  : (fscope->isCoroutine()
2127  ? CheckFallThroughDiagnostics::MakeForCoroutine(D)
2128  : CheckFallThroughDiagnostics::MakeForFunction(D)));
2129  CheckFallThroughForBody(S, D, Body, blkExpr, CD, AC, fscope);
2130  }
2131 
2132  // Warning: check for unreachable code
2133  if (P.enableCheckUnreachable) {
2134  // Only check for unreachable code on non-template instantiations.
2135  // Different template instantiations can effectively change the control-flow
2136  // and it is very difficult to prove that a snippet of code in a template
2137  // is unreachable for all instantiations.
2138  bool isTemplateInstantiation = false;
2139  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
2140  isTemplateInstantiation = Function->isTemplateInstantiation();
2141  if (!isTemplateInstantiation)
2142  CheckUnreachable(S, AC);
2143  }
2144 
2145  // Check for thread safety violations
2146  if (P.enableThreadSafetyAnalysis) {
2147  SourceLocation FL = AC.getDecl()->getLocation();
2148  SourceLocation FEL = AC.getDecl()->getLocEnd();
2149  threadSafety::ThreadSafetyReporter Reporter(S, FL, FEL);
2150  if (!Diags.isIgnored(diag::warn_thread_safety_beta, D->getLocStart()))
2151  Reporter.setIssueBetaWarnings(true);
2152  if (!Diags.isIgnored(diag::warn_thread_safety_verbose, D->getLocStart()))
2153  Reporter.setVerbose(true);
2154 
2157  Reporter.emitDiagnostics();
2158  }
2159 
2160  // Check for violations of consumed properties.
2161  if (P.enableConsumedAnalysis) {
2162  consumed::ConsumedWarningsHandler WarningHandler(S);
2163  consumed::ConsumedAnalyzer Analyzer(WarningHandler);
2164  Analyzer.run(AC);
2165  }
2166 
2167  if (!Diags.isIgnored(diag::warn_uninit_var, D->getLocStart()) ||
2168  !Diags.isIgnored(diag::warn_sometimes_uninit_var, D->getLocStart()) ||
2169  !Diags.isIgnored(diag::warn_maybe_uninit_var, D->getLocStart())) {
2170  if (CFG *cfg = AC.getCFG()) {
2171  UninitValsDiagReporter reporter(S);
2173  std::memset(&stats, 0, sizeof(UninitVariablesAnalysisStats));
2174  runUninitializedVariablesAnalysis(*cast<DeclContext>(D), *cfg, AC,
2175  reporter, stats);
2176 
2177  if (S.CollectStats && stats.NumVariablesAnalyzed > 0) {
2178  ++NumUninitAnalysisFunctions;
2179  NumUninitAnalysisVariables += stats.NumVariablesAnalyzed;
2180  NumUninitAnalysisBlockVisits += stats.NumBlockVisits;
2181  MaxUninitAnalysisVariablesPerFunction =
2182  std::max(MaxUninitAnalysisVariablesPerFunction,
2183  stats.NumVariablesAnalyzed);
2184  MaxUninitAnalysisBlockVisitsPerFunction =
2185  std::max(MaxUninitAnalysisBlockVisitsPerFunction,
2186  stats.NumBlockVisits);
2187  }
2188  }
2189  }
2190 
2191  bool FallThroughDiagFull =
2192  !Diags.isIgnored(diag::warn_unannotated_fallthrough, D->getLocStart());
2193  bool FallThroughDiagPerFunction = !Diags.isIgnored(
2194  diag::warn_unannotated_fallthrough_per_function, D->getLocStart());
2195  if (FallThroughDiagFull || FallThroughDiagPerFunction ||
2196  fscope->HasFallthroughStmt) {
2197  DiagnoseSwitchLabelsFallthrough(S, AC, !FallThroughDiagFull);
2198  }
2199 
2200  if (S.getLangOpts().ObjCWeak &&
2201  !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, D->getLocStart()))
2202  diagnoseRepeatedUseOfWeak(S, fscope, D, AC.getParentMap());
2203 
2204 
2205  // Check for infinite self-recursion in functions
2206  if (!Diags.isIgnored(diag::warn_infinite_recursive_function,
2207  D->getLocStart())) {
2208  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
2209  checkRecursiveFunction(S, FD, Body, AC);
2210  }
2211  }
2212 
2213  // Check for throw out of non-throwing function.
2214  if (!Diags.isIgnored(diag::warn_throw_in_noexcept_func, D->getLocStart()))
2215  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
2216  if (S.getLangOpts().CPlusPlus && isNoexcept(FD))
2217  checkThrowInNonThrowingFunc(S, FD, AC);
2218 
2219  // If none of the previous checks caused a CFG build, trigger one here
2220  // for -Wtautological-overlap-compare
2221  if (!Diags.isIgnored(diag::warn_tautological_overlap_comparison,
2222  D->getLocStart())) {
2223  AC.getCFG();
2224  }
2225 
2226  // Collect statistics about the CFG if it was built.
2227  if (S.CollectStats && AC.isCFGBuilt()) {
2228  ++NumFunctionsAnalyzed;
2229  if (CFG *cfg = AC.getCFG()) {
2230  // If we successfully built a CFG for this context, record some more
2231  // detail information about it.
2232  NumCFGBlocks += cfg->getNumBlockIDs();
2233  MaxCFGBlocksPerFunction = std::max(MaxCFGBlocksPerFunction,
2234  cfg->getNumBlockIDs());
2235  } else {
2236  ++NumFunctionsWithBadCFGs;
2237  }
2238  }
2239 }
2240 
2242  llvm::errs() << "\n*** Analysis Based Warnings Stats:\n";
2243 
2244  unsigned NumCFGsBuilt = NumFunctionsAnalyzed - NumFunctionsWithBadCFGs;
2245  unsigned AvgCFGBlocksPerFunction =
2246  !NumCFGsBuilt ? 0 : NumCFGBlocks/NumCFGsBuilt;
2247  llvm::errs() << NumFunctionsAnalyzed << " functions analyzed ("
2248  << NumFunctionsWithBadCFGs << " w/o CFGs).\n"
2249  << " " << NumCFGBlocks << " CFG blocks built.\n"
2250  << " " << AvgCFGBlocksPerFunction
2251  << " average CFG blocks per function.\n"
2252  << " " << MaxCFGBlocksPerFunction
2253  << " max CFG blocks per function.\n";
2254 
2255  unsigned AvgUninitVariablesPerFunction = !NumUninitAnalysisFunctions ? 0
2256  : NumUninitAnalysisVariables/NumUninitAnalysisFunctions;
2257  unsigned AvgUninitBlockVisitsPerFunction = !NumUninitAnalysisFunctions ? 0
2258  : NumUninitAnalysisBlockVisits/NumUninitAnalysisFunctions;
2259  llvm::errs() << NumUninitAnalysisFunctions
2260  << " functions analyzed for uninitialiazed variables\n"
2261  << " " << NumUninitAnalysisVariables << " variables analyzed.\n"
2262  << " " << AvgUninitVariablesPerFunction
2263  << " average variables per function.\n"
2264  << " " << MaxUninitAnalysisVariablesPerFunction
2265  << " max variables per function.\n"
2266  << " " << NumUninitAnalysisBlockVisits << " block visits.\n"
2267  << " " << AvgUninitBlockVisitsPerFunction
2268  << " average block visits per function.\n"
2269  << " " << MaxUninitAnalysisBlockVisitsPerFunction
2270  << " max block visits per function.\n";
2271 }
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:1716
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:1014
pred_iterator pred_end()
Definition: CFG.h:734
A (possibly-)qualified type.
Definition: Type.h:655
bool isBlockPointerType() const
Definition: Type.h:6121
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:1050
const Stmt * getStmt() const
Definition: CFG.h:133
Stmt * getBody() const
Get the body of the Declaration.
succ_iterator succ_begin()
Definition: CFG.h:751
virtual Stmt * getBody() const
getBody - If this Decl represents a declaration for a body of code, such as a function or method defi...
Definition: DeclBase.h:986
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3211
CFGBlock & getEntry()
Definition: CFG.h:1093
IfStmt - This represents an if/then/else.
Definition: Stmt.h:974
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:497
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:856
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID)
Emit a diagnostic.
Definition: Sema.h:1281
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:2090
Opcode getOpcode() const
Definition: Expr.h:3184
StringRef P
Represents an attribute applied to a statement.
Definition: Stmt.h:918
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:385
The use is uninitialized whenever a certain branch is taken.
Stmt * getParent(Stmt *) const
Definition: ParentMap.cpp:123
iterator begin()
Definition: CFG.h:703
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:99
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:414
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:779
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:814
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:6526
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:1028
Defines the clang::Expr interface and subclasses for C++ expressions.
SourceLocation getLocStart() const LLVM_READONLY
Definition: Expr.h:5074
branch_iterator branch_end() const
LabelStmt - Represents a label, which has a substatement.
Definition: Stmt.h:875
LockKind
This enum distinguishes between different kinds of lock actions.
Definition: ThreadSafety.h:57
bool pred_empty() const
Definition: CFG.h:773
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:3472
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:7593
static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC, bool PerFunction)
succ_range succs()
Definition: CFG.h:761
const LangOptions & getLangOpts() const
Definition: Preprocessor.h:821
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:727
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:1027
CFGReverseBlockReachabilityAnalysis * getCFGReachablityAnalysis()
CFGCallback * Observer
Definition: CFG.h:1016
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:3143
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:1053
Expr * IgnoreParenCasts() LLVM_READONLY
IgnoreParenCasts - Ignore parentheses and casts.
Definition: Expr.cpp:2544
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:828
__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:1649
const LangOptions & getLangOpts() const
Definition: Sema.h:1204
SourceRange getExceptionSpecSourceRange() const
Attempt to compute an informative source range covering the function exception specification, if any.
Definition: Decl.cpp:3138
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:877
reverse_iterator rend()
Definition: CFG.h:709
static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD)
DiagnosticsEngine & getDiagnostics() const
Definition: Sema.h:1208
Passing a pt-guarded variable by reference.
Definition: ThreadSafety.h:51
bool hasAttr() const
Definition: DeclBase.h:538
ConditionalOperator - The ?: ternary operator.
Definition: Expr.h:3429
Sema - This implements semantic analysis and AST building for C.
Definition: Sema.h:277
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3432
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
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:1837
Represents a single basic block in a source-level CFG.
Definition: CFG.h:552
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:3463
Expr - This represents one expression.
Definition: Expr.h:106
std::string Label
Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:1003
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:6589
const Stmt * getThen() const
Definition: Stmt.h:1012
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5051
const Expr * getCallee() const
Definition: Expr.h:2356
Defines the clang::Preprocessor interface.
bool isCPUDispatchMultiVersion() const
True if this function is a multiversioned dispatch function as a part of the cpu_specific/cpu_dispatc...
Definition: Decl.cpp:2876
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:1210
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:708
VarDecl * CoroutinePromise
The promise object for this coroutine, if any.
Definition: ScopeInfo.h:192
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:840
Kind
QualType getCanonicalType() const
Definition: Type.h:5928
Reading or writing a variable (e.g. x in x = 5;)
Definition: ThreadSafety.h:42
FunctionDecl * getAsFunction() LLVM_READONLY
Returns the function itself, or the templated function if this is a function template.
Definition: DeclBase.cpp:218
ASTContext & getASTContext() const
Definition: Sema.h:1211
Encodes a location in the source.
BuildOptions & setAlwaysAdd(Stmt::StmtClass stmtClass, bool val=true)
Definition: CFG.h:1037
static void visitReachableThrows(CFG *BodyCFG, llvm::function_ref< void(const CXXThrowExpr *, CFGBlock &)> Visit)
SourceLocation getOperatorLoc() const
Definition: Expr.h:3181
static void EmitDiagForCXXThrowInNonThrowingFunc(Sema &S, SourceLocation OpLoc, const FunctionDecl *FD)
Stmt * getLabel()
Definition: CFG.h:851
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:3192
Represents a call to a member function that may be written either with member call syntax (e...
Definition: ExprCXX.h:166
SourceLocation getLocStart() const LLVM_READONLY
Definition: Stmt.h:401
bool PruneTriviallyFalseEdges
Definition: CFG.h:1017
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:2045
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:325
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:748
unsigned getNumBlockIDs() const
Returns the total number of BlockIDs allocated (which start at 0).
Definition: CFG.h:1169
SourceLocation getLocEnd() const LLVM_READONLY
Definition: Stmt.h:403
SourceRange getSourceRange() const override LLVM_READONLY
Source range that this declaration covers.
Definition: Decl.cpp:1938
static bool isLogicalOp(Opcode Opc)
Definition: Expr.h:3265
static void emitDiagnostics(BoundNodes &Match, const Decl *D, BugReporter &BR, AnalysisManager &AM, const ObjCAutoreleaseWriteChecker *Checker)
succ_iterator succ_end()
Definition: CFG.h:752
BuildOptions & setAllAlwaysAdd()
Definition: CFG.h:1042
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:110
Expr * getLHS() const
Definition: Expr.h:3187
pred_iterator pred_begin()
Definition: CFG.h:733
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:1219
static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg)
StmtClass getStmtClass() const
Definition: Stmt.h:391
Represents a simple identification of a weak object.
Definition: ScopeInfo.h:237
SourceLocation getLocStart() const LLVM_READONLY
Definition: Decl.h:739
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:2631
Decl * getCalleeDecl()
Definition: Expr.cpp:1255
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:1054
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:716
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:3180
static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope)
Stmt * getSubStmt()
Definition: Stmt.cpp:886
bool hasNoReturnElement() const
Definition: CFG.h:854
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:208
CFGCallback defines methods that should be called when a logical operator error is found when buildin...
Definition: CFG.h:986
bool isValid() const
Expr * getTrueExpr() const
Definition: Expr.h:3467
void run(AnalysisDeclContext &AC)
Check a function&#39;s CFG for consumed violations.
Definition: Consumed.cpp:1309
Represents a top-level expression in a basic block.
Definition: CFG.h:56
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:1209
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:2316
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:346
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:974
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:3246
SourceManager & SourceMgr
Definition: Sema.h:322
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:895
QualType getType() const
Definition: Decl.h:648
const Expr * getCond() const
Definition: Stmt.h:1010
A trivial tuple used to represent a source range.
ASTContext & Context
Definition: Sema.h:319
FunctionDecl * getCanonicalDecl() override
Retrieves the "canonical" declaration of the given declaration.
Definition: Decl.cpp:2899
This represents a decl that may have a name.
Definition: Decl.h:248
iterator end()
Definition: CFG.h:704
SourceLocation getBegin() const
const LangOptions & getLangOpts() const
Definition: ASTContext.h:696
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:419
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:1095