clang  12.0.0git
AnalysisBasedWarnings.cpp
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1 //=- AnalysisBasedWarnings.cpp - Sema warnings based on libAnalysis -*- C++ -*-=//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines analysis_warnings::[Policy,Executor].
10 // Together they are used by Sema to issue warnings based on inexpensive
11 // static analysis algorithms in libAnalysis.
12 //
13 //===----------------------------------------------------------------------===//
14 
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/DeclObjC.h"
19 #include "clang/AST/ExprCXX.h"
20 #include "clang/AST/ExprObjC.h"
21 #include "clang/AST/ParentMap.h"
23 #include "clang/AST/StmtCXX.h"
24 #include "clang/AST/StmtObjC.h"
25 #include "clang/AST/StmtVisitor.h"
32 #include "clang/Analysis/CFG.h"
36 #include "clang/Lex/Preprocessor.h"
37 #include "clang/Sema/ScopeInfo.h"
39 #include "llvm/ADT/BitVector.h"
40 #include "llvm/ADT/MapVector.h"
41 #include "llvm/ADT/SmallString.h"
42 #include "llvm/ADT/SmallVector.h"
43 #include "llvm/ADT/StringRef.h"
44 #include "llvm/Support/Casting.h"
45 #include <algorithm>
46 #include <deque>
47 #include <iterator>
48 
49 using namespace clang;
50 
51 //===----------------------------------------------------------------------===//
52 // Unreachable code analysis.
53 //===----------------------------------------------------------------------===//
54 
55 namespace {
56  class UnreachableCodeHandler : public reachable_code::Callback {
57  Sema &S;
58  SourceRange PreviousSilenceableCondVal;
59 
60  public:
61  UnreachableCodeHandler(Sema &s) : S(s) {}
62 
63  void HandleUnreachable(reachable_code::UnreachableKind UK,
65  SourceRange SilenceableCondVal,
66  SourceRange R1,
67  SourceRange R2) override {
68  // Avoid reporting multiple unreachable code diagnostics that are
69  // triggered by the same conditional value.
70  if (PreviousSilenceableCondVal.isValid() &&
71  SilenceableCondVal.isValid() &&
72  PreviousSilenceableCondVal == SilenceableCondVal)
73  return;
74  PreviousSilenceableCondVal = SilenceableCondVal;
75 
76  unsigned diag = diag::warn_unreachable;
77  switch (UK) {
79  diag = diag::warn_unreachable_break;
80  break;
82  diag = diag::warn_unreachable_return;
83  break;
85  diag = diag::warn_unreachable_loop_increment;
86  break;
88  break;
89  }
90 
91  S.Diag(L, diag) << R1 << R2;
92 
93  SourceLocation Open = SilenceableCondVal.getBegin();
94  if (Open.isValid()) {
95  SourceLocation Close = SilenceableCondVal.getEnd();
96  Close = S.getLocForEndOfToken(Close);
97  if (Close.isValid()) {
98  S.Diag(Open, diag::note_unreachable_silence)
99  << FixItHint::CreateInsertion(Open, "/* DISABLES CODE */ (")
100  << FixItHint::CreateInsertion(Close, ")");
101  }
102  }
103  }
104  };
105 } // anonymous namespace
106 
107 /// CheckUnreachable - Check for unreachable code.
109  // As a heuristic prune all diagnostics not in the main file. Currently
110  // the majority of warnings in headers are false positives. These
111  // are largely caused by configuration state, e.g. preprocessor
112  // defined code, etc.
113  //
114  // Note that this is also a performance optimization. Analyzing
115  // headers many times can be expensive.
117  return;
118 
119  UnreachableCodeHandler UC(S);
121 }
122 
123 namespace {
124 /// Warn on logical operator errors in CFGBuilder
125 class LogicalErrorHandler : public CFGCallback {
126  Sema &S;
127 
128 public:
129  LogicalErrorHandler(Sema &S) : CFGCallback(), S(S) {}
130 
131  static bool HasMacroID(const Expr *E) {
132  if (E->getExprLoc().isMacroID())
133  return true;
134 
135  // Recurse to children.
136  for (const Stmt *SubStmt : E->children())
137  if (const Expr *SubExpr = dyn_cast_or_null<Expr>(SubStmt))
138  if (HasMacroID(SubExpr))
139  return true;
140 
141  return false;
142  }
143 
144  void compareAlwaysTrue(const BinaryOperator *B, bool isAlwaysTrue) override {
145  if (HasMacroID(B))
146  return;
147 
148  SourceRange DiagRange = B->getSourceRange();
149  S.Diag(B->getExprLoc(), diag::warn_tautological_overlap_comparison)
150  << DiagRange << isAlwaysTrue;
151  }
152 
153  void compareBitwiseEquality(const BinaryOperator *B,
154  bool isAlwaysTrue) override {
155  if (HasMacroID(B))
156  return;
157 
158  SourceRange DiagRange = B->getSourceRange();
159  S.Diag(B->getExprLoc(), diag::warn_comparison_bitwise_always)
160  << DiagRange << isAlwaysTrue;
161  }
162 
163  void compareBitwiseOr(const BinaryOperator *B) override {
164  if (HasMacroID(B))
165  return;
166 
167  SourceRange DiagRange = B->getSourceRange();
168  S.Diag(B->getExprLoc(), diag::warn_comparison_bitwise_or) << DiagRange;
169  }
170 
171  static bool hasActiveDiagnostics(DiagnosticsEngine &Diags,
172  SourceLocation Loc) {
173  return !Diags.isIgnored(diag::warn_tautological_overlap_comparison, Loc) ||
174  !Diags.isIgnored(diag::warn_comparison_bitwise_or, Loc);
175  }
176 };
177 } // anonymous namespace
178 
179 //===----------------------------------------------------------------------===//
180 // Check for infinite self-recursion in functions
181 //===----------------------------------------------------------------------===//
182 
183 // Returns true if the function is called anywhere within the CFGBlock.
184 // For member functions, the additional condition of being call from the
185 // this pointer is required.
186 static bool hasRecursiveCallInPath(const FunctionDecl *FD, CFGBlock &Block) {
187  // Process all the Stmt's in this block to find any calls to FD.
188  for (const auto &B : Block) {
189  if (B.getKind() != CFGElement::Statement)
190  continue;
191 
192  const CallExpr *CE = dyn_cast<CallExpr>(B.getAs<CFGStmt>()->getStmt());
193  if (!CE || !CE->getCalleeDecl() ||
194  CE->getCalleeDecl()->getCanonicalDecl() != FD)
195  continue;
196 
197  // Skip function calls which are qualified with a templated class.
198  if (const DeclRefExpr *DRE =
199  dyn_cast<DeclRefExpr>(CE->getCallee()->IgnoreParenImpCasts())) {
200  if (NestedNameSpecifier *NNS = DRE->getQualifier()) {
201  if (NNS->getKind() == NestedNameSpecifier::TypeSpec &&
202  isa<TemplateSpecializationType>(NNS->getAsType())) {
203  continue;
204  }
205  }
206  }
207 
208  const CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(CE);
209  if (!MCE || isa<CXXThisExpr>(MCE->getImplicitObjectArgument()) ||
210  !MCE->getMethodDecl()->isVirtual())
211  return true;
212  }
213  return false;
214 }
215 
216 // Returns true if every path from the entry block passes through a call to FD.
217 static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg) {
220  // Keep track of whether we found at least one recursive path.
221  bool foundRecursion = false;
222 
223  const unsigned ExitID = cfg->getExit().getBlockID();
224 
225  // Seed the work list with the entry block.
226  WorkList.push_back(&cfg->getEntry());
227 
228  while (!WorkList.empty()) {
229  CFGBlock *Block = WorkList.pop_back_val();
230 
231  for (auto I = Block->succ_begin(), E = Block->succ_end(); I != E; ++I) {
232  if (CFGBlock *SuccBlock = *I) {
233  if (!Visited.insert(SuccBlock).second)
234  continue;
235 
236  // Found a path to the exit node without a recursive call.
237  if (ExitID == SuccBlock->getBlockID())
238  return false;
239 
240  // If the successor block contains a recursive call, end analysis there.
241  if (hasRecursiveCallInPath(FD, *SuccBlock)) {
242  foundRecursion = true;
243  continue;
244  }
245 
246  WorkList.push_back(SuccBlock);
247  }
248  }
249  }
250  return foundRecursion;
251 }
252 
253 static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD,
254  const Stmt *Body, AnalysisDeclContext &AC) {
255  FD = FD->getCanonicalDecl();
256 
257  // Only run on non-templated functions and non-templated members of
258  // templated classes.
261  return;
262 
263  CFG *cfg = AC.getCFG();
264  if (!cfg) return;
265 
266  // If the exit block is unreachable, skip processing the function.
267  if (cfg->getExit().pred_empty())
268  return;
269 
270  // Emit diagnostic if a recursive function call is detected for all paths.
271  if (checkForRecursiveFunctionCall(FD, cfg))
272  S.Diag(Body->getBeginLoc(), diag::warn_infinite_recursive_function);
273 }
274 
275 //===----------------------------------------------------------------------===//
276 // Check for throw in a non-throwing function.
277 //===----------------------------------------------------------------------===//
278 
279 /// Determine whether an exception thrown by E, unwinding from ThrowBlock,
280 /// can reach ExitBlock.
281 static bool throwEscapes(Sema &S, const CXXThrowExpr *E, CFGBlock &ThrowBlock,
282  CFG *Body) {
284  llvm::BitVector Queued(Body->getNumBlockIDs());
285 
286  Stack.push_back(&ThrowBlock);
287  Queued[ThrowBlock.getBlockID()] = true;
288 
289  while (!Stack.empty()) {
290  CFGBlock &UnwindBlock = *Stack.back();
291  Stack.pop_back();
292 
293  for (auto &Succ : UnwindBlock.succs()) {
294  if (!Succ.isReachable() || Queued[Succ->getBlockID()])
295  continue;
296 
297  if (Succ->getBlockID() == Body->getExit().getBlockID())
298  return true;
299 
300  if (auto *Catch =
301  dyn_cast_or_null<CXXCatchStmt>(Succ->getLabel())) {
302  QualType Caught = Catch->getCaughtType();
303  if (Caught.isNull() || // catch (...) catches everything
304  !E->getSubExpr() || // throw; is considered cuaght by any handler
305  S.handlerCanCatch(Caught, E->getSubExpr()->getType()))
306  // Exception doesn't escape via this path.
307  break;
308  } else {
309  Stack.push_back(Succ);
310  Queued[Succ->getBlockID()] = true;
311  }
312  }
313  }
314 
315  return false;
316 }
317 
319  CFG *BodyCFG,
320  llvm::function_ref<void(const CXXThrowExpr *, CFGBlock &)> Visit) {
321  llvm::BitVector Reachable(BodyCFG->getNumBlockIDs());
323  for (CFGBlock *B : *BodyCFG) {
324  if (!Reachable[B->getBlockID()])
325  continue;
326  for (CFGElement &E : *B) {
327  Optional<CFGStmt> S = E.getAs<CFGStmt>();
328  if (!S)
329  continue;
330  if (auto *Throw = dyn_cast<CXXThrowExpr>(S->getStmt()))
331  Visit(Throw, *B);
332  }
333  }
334 }
335 
337  const FunctionDecl *FD) {
338  if (!S.getSourceManager().isInSystemHeader(OpLoc) &&
339  FD->getTypeSourceInfo()) {
340  S.Diag(OpLoc, diag::warn_throw_in_noexcept_func) << FD;
341  if (S.getLangOpts().CPlusPlus11 &&
342  (isa<CXXDestructorDecl>(FD) ||
343  FD->getDeclName().getCXXOverloadedOperator() == OO_Delete ||
344  FD->getDeclName().getCXXOverloadedOperator() == OO_Array_Delete)) {
345  if (const auto *Ty = FD->getTypeSourceInfo()->getType()->
346  getAs<FunctionProtoType>())
347  S.Diag(FD->getLocation(), diag::note_throw_in_dtor)
348  << !isa<CXXDestructorDecl>(FD) << !Ty->hasExceptionSpec()
350  } else
351  S.Diag(FD->getLocation(), diag::note_throw_in_function)
353  }
354 }
355 
357  AnalysisDeclContext &AC) {
358  CFG *BodyCFG = AC.getCFG();
359  if (!BodyCFG)
360  return;
361  if (BodyCFG->getExit().pred_empty())
362  return;
363  visitReachableThrows(BodyCFG, [&](const CXXThrowExpr *Throw, CFGBlock &Block) {
364  if (throwEscapes(S, Throw, Block, BodyCFG))
366  });
367 }
368 
369 static bool isNoexcept(const FunctionDecl *FD) {
370  const auto *FPT = FD->getType()->castAs<FunctionProtoType>();
371  if (FPT->isNothrow() || FD->hasAttr<NoThrowAttr>())
372  return true;
373  return false;
374 }
375 
376 //===----------------------------------------------------------------------===//
377 // Check for missing return value.
378 //===----------------------------------------------------------------------===//
379 
386 };
387 
388 /// CheckFallThrough - Check that we don't fall off the end of a
389 /// Statement that should return a value.
390 ///
391 /// \returns AlwaysFallThrough iff we always fall off the end of the statement,
392 /// MaybeFallThrough iff we might or might not fall off the end,
393 /// NeverFallThroughOrReturn iff we never fall off the end of the statement or
394 /// return. We assume NeverFallThrough iff we never fall off the end of the
395 /// statement but we may return. We assume that functions not marked noreturn
396 /// will return.
398  CFG *cfg = AC.getCFG();
399  if (!cfg) return UnknownFallThrough;
400 
401  // The CFG leaves in dead things, and we don't want the dead code paths to
402  // confuse us, so we mark all live things first.
403  llvm::BitVector live(cfg->getNumBlockIDs());
404  unsigned count = reachable_code::ScanReachableFromBlock(&cfg->getEntry(),
405  live);
406 
407  bool AddEHEdges = AC.getAddEHEdges();
408  if (!AddEHEdges && count != cfg->getNumBlockIDs())
409  // When there are things remaining dead, and we didn't add EH edges
410  // from CallExprs to the catch clauses, we have to go back and
411  // mark them as live.
412  for (const auto *B : *cfg) {
413  if (!live[B->getBlockID()]) {
414  if (B->pred_begin() == B->pred_end()) {
415  const Stmt *Term = B->getTerminatorStmt();
416  if (Term && isa<CXXTryStmt>(Term))
417  // When not adding EH edges from calls, catch clauses
418  // can otherwise seem dead. Avoid noting them as dead.
419  count += reachable_code::ScanReachableFromBlock(B, live);
420  continue;
421  }
422  }
423  }
424 
425  // Now we know what is live, we check the live precessors of the exit block
426  // and look for fall through paths, being careful to ignore normal returns,
427  // and exceptional paths.
428  bool HasLiveReturn = false;
429  bool HasFakeEdge = false;
430  bool HasPlainEdge = false;
431  bool HasAbnormalEdge = false;
432 
433  // Ignore default cases that aren't likely to be reachable because all
434  // enums in a switch(X) have explicit case statements.
437 
439  cfg->getExit().filtered_pred_start_end(FO);
440  I.hasMore(); ++I) {
441  const CFGBlock &B = **I;
442  if (!live[B.getBlockID()])
443  continue;
444 
445  // Skip blocks which contain an element marked as no-return. They don't
446  // represent actually viable edges into the exit block, so mark them as
447  // abnormal.
448  if (B.hasNoReturnElement()) {
449  HasAbnormalEdge = true;
450  continue;
451  }
452 
453  // Destructors can appear after the 'return' in the CFG. This is
454  // normal. We need to look pass the destructors for the return
455  // statement (if it exists).
456  CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend();
457 
458  for ( ; ri != re ; ++ri)
459  if (ri->getAs<CFGStmt>())
460  break;
461 
462  // No more CFGElements in the block?
463  if (ri == re) {
464  const Stmt *Term = B.getTerminatorStmt();
465  if (Term && isa<CXXTryStmt>(Term)) {
466  HasAbnormalEdge = true;
467  continue;
468  }
469  // A labeled empty statement, or the entry block...
470  HasPlainEdge = true;
471  continue;
472  }
473 
474  CFGStmt CS = ri->castAs<CFGStmt>();
475  const Stmt *S = CS.getStmt();
476  if (isa<ReturnStmt>(S) || isa<CoreturnStmt>(S)) {
477  HasLiveReturn = true;
478  continue;
479  }
480  if (isa<ObjCAtThrowStmt>(S)) {
481  HasFakeEdge = true;
482  continue;
483  }
484  if (isa<CXXThrowExpr>(S)) {
485  HasFakeEdge = true;
486  continue;
487  }
488  if (isa<MSAsmStmt>(S)) {
489  // TODO: Verify this is correct.
490  HasFakeEdge = true;
491  HasLiveReturn = true;
492  continue;
493  }
494  if (isa<CXXTryStmt>(S)) {
495  HasAbnormalEdge = true;
496  continue;
497  }
498  if (std::find(B.succ_begin(), B.succ_end(), &cfg->getExit())
499  == B.succ_end()) {
500  HasAbnormalEdge = true;
501  continue;
502  }
503 
504  HasPlainEdge = true;
505  }
506  if (!HasPlainEdge) {
507  if (HasLiveReturn)
508  return NeverFallThrough;
510  }
511  if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
512  return MaybeFallThrough;
513  // This says AlwaysFallThrough for calls to functions that are not marked
514  // noreturn, that don't return. If people would like this warning to be more
515  // accurate, such functions should be marked as noreturn.
516  return AlwaysFallThrough;
517 }
518 
519 namespace {
520 
521 struct CheckFallThroughDiagnostics {
522  unsigned diag_MaybeFallThrough_HasNoReturn;
523  unsigned diag_MaybeFallThrough_ReturnsNonVoid;
524  unsigned diag_AlwaysFallThrough_HasNoReturn;
525  unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
526  unsigned diag_NeverFallThroughOrReturn;
527  enum { Function, Block, Lambda, Coroutine } funMode;
528  SourceLocation FuncLoc;
529 
530  static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
531  CheckFallThroughDiagnostics D;
532  D.FuncLoc = Func->getLocation();
533  D.diag_MaybeFallThrough_HasNoReturn =
534  diag::warn_falloff_noreturn_function;
535  D.diag_MaybeFallThrough_ReturnsNonVoid =
536  diag::warn_maybe_falloff_nonvoid_function;
537  D.diag_AlwaysFallThrough_HasNoReturn =
538  diag::warn_falloff_noreturn_function;
539  D.diag_AlwaysFallThrough_ReturnsNonVoid =
540  diag::warn_falloff_nonvoid_function;
541 
542  // Don't suggest that virtual functions be marked "noreturn", since they
543  // might be overridden by non-noreturn functions.
544  bool isVirtualMethod = false;
545  if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Func))
546  isVirtualMethod = Method->isVirtual();
547 
548  // Don't suggest that template instantiations be marked "noreturn"
549  bool isTemplateInstantiation = false;
550  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Func))
551  isTemplateInstantiation = Function->isTemplateInstantiation();
552 
553  if (!isVirtualMethod && !isTemplateInstantiation)
554  D.diag_NeverFallThroughOrReturn =
555  diag::warn_suggest_noreturn_function;
556  else
557  D.diag_NeverFallThroughOrReturn = 0;
558 
559  D.funMode = Function;
560  return D;
561  }
562 
563  static CheckFallThroughDiagnostics MakeForCoroutine(const Decl *Func) {
564  CheckFallThroughDiagnostics D;
565  D.FuncLoc = Func->getLocation();
566  D.diag_MaybeFallThrough_HasNoReturn = 0;
567  D.diag_MaybeFallThrough_ReturnsNonVoid =
568  diag::warn_maybe_falloff_nonvoid_coroutine;
569  D.diag_AlwaysFallThrough_HasNoReturn = 0;
570  D.diag_AlwaysFallThrough_ReturnsNonVoid =
571  diag::warn_falloff_nonvoid_coroutine;
572  D.funMode = Coroutine;
573  return D;
574  }
575 
576  static CheckFallThroughDiagnostics MakeForBlock() {
577  CheckFallThroughDiagnostics D;
578  D.diag_MaybeFallThrough_HasNoReturn =
579  diag::err_noreturn_block_has_return_expr;
580  D.diag_MaybeFallThrough_ReturnsNonVoid =
581  diag::err_maybe_falloff_nonvoid_block;
582  D.diag_AlwaysFallThrough_HasNoReturn =
583  diag::err_noreturn_block_has_return_expr;
584  D.diag_AlwaysFallThrough_ReturnsNonVoid =
585  diag::err_falloff_nonvoid_block;
586  D.diag_NeverFallThroughOrReturn = 0;
587  D.funMode = Block;
588  return D;
589  }
590 
591  static CheckFallThroughDiagnostics MakeForLambda() {
592  CheckFallThroughDiagnostics D;
593  D.diag_MaybeFallThrough_HasNoReturn =
594  diag::err_noreturn_lambda_has_return_expr;
595  D.diag_MaybeFallThrough_ReturnsNonVoid =
596  diag::warn_maybe_falloff_nonvoid_lambda;
597  D.diag_AlwaysFallThrough_HasNoReturn =
598  diag::err_noreturn_lambda_has_return_expr;
599  D.diag_AlwaysFallThrough_ReturnsNonVoid =
600  diag::warn_falloff_nonvoid_lambda;
601  D.diag_NeverFallThroughOrReturn = 0;
602  D.funMode = Lambda;
603  return D;
604  }
605 
606  bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
607  bool HasNoReturn) const {
608  if (funMode == Function) {
609  return (ReturnsVoid ||
610  D.isIgnored(diag::warn_maybe_falloff_nonvoid_function,
611  FuncLoc)) &&
612  (!HasNoReturn ||
613  D.isIgnored(diag::warn_noreturn_function_has_return_expr,
614  FuncLoc)) &&
615  (!ReturnsVoid ||
616  D.isIgnored(diag::warn_suggest_noreturn_block, FuncLoc));
617  }
618  if (funMode == Coroutine) {
619  return (ReturnsVoid ||
620  D.isIgnored(diag::warn_maybe_falloff_nonvoid_function, FuncLoc) ||
621  D.isIgnored(diag::warn_maybe_falloff_nonvoid_coroutine,
622  FuncLoc)) &&
623  (!HasNoReturn);
624  }
625  // For blocks / lambdas.
626  return ReturnsVoid && !HasNoReturn;
627  }
628 };
629 
630 } // anonymous namespace
631 
632 /// CheckFallThroughForBody - Check that we don't fall off the end of a
633 /// function that should return a value. Check that we don't fall off the end
634 /// of a noreturn function. We assume that functions and blocks not marked
635 /// noreturn will return.
636 static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
637  QualType BlockType,
638  const CheckFallThroughDiagnostics &CD,
641 
642  bool ReturnsVoid = false;
643  bool HasNoReturn = false;
644  bool IsCoroutine = FSI->isCoroutine();
645 
646  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
647  if (const auto *CBody = dyn_cast<CoroutineBodyStmt>(Body))
648  ReturnsVoid = CBody->getFallthroughHandler() != nullptr;
649  else
650  ReturnsVoid = FD->getReturnType()->isVoidType();
651  HasNoReturn = FD->isNoReturn();
652  }
653  else if (const auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
654  ReturnsVoid = MD->getReturnType()->isVoidType();
655  HasNoReturn = MD->hasAttr<NoReturnAttr>();
656  }
657  else if (isa<BlockDecl>(D)) {
658  if (const FunctionType *FT =
659  BlockType->getPointeeType()->getAs<FunctionType>()) {
660  if (FT->getReturnType()->isVoidType())
661  ReturnsVoid = true;
662  if (FT->getNoReturnAttr())
663  HasNoReturn = true;
664  }
665  }
666 
667  DiagnosticsEngine &Diags = S.getDiagnostics();
668 
669  // Short circuit for compilation speed.
670  if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn))
671  return;
672  SourceLocation LBrace = Body->getBeginLoc(), RBrace = Body->getEndLoc();
673  auto EmitDiag = [&](SourceLocation Loc, unsigned DiagID) {
674  if (IsCoroutine)
675  S.Diag(Loc, DiagID) << FSI->CoroutinePromise->getType();
676  else
677  S.Diag(Loc, DiagID);
678  };
679 
680  // cpu_dispatch functions permit empty function bodies for ICC compatibility.
682  return;
683 
684  // Either in a function body compound statement, or a function-try-block.
685  switch (CheckFallThrough(AC)) {
686  case UnknownFallThrough:
687  break;
688 
689  case MaybeFallThrough:
690  if (HasNoReturn)
691  EmitDiag(RBrace, CD.diag_MaybeFallThrough_HasNoReturn);
692  else if (!ReturnsVoid)
693  EmitDiag(RBrace, CD.diag_MaybeFallThrough_ReturnsNonVoid);
694  break;
695  case AlwaysFallThrough:
696  if (HasNoReturn)
697  EmitDiag(RBrace, CD.diag_AlwaysFallThrough_HasNoReturn);
698  else if (!ReturnsVoid)
699  EmitDiag(RBrace, CD.diag_AlwaysFallThrough_ReturnsNonVoid);
700  break;
702  if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
703  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
704  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 0 << FD;
705  } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
706  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 1 << MD;
707  } else {
708  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn);
709  }
710  }
711  break;
712  case NeverFallThrough:
713  break;
714  }
715 }
716 
717 //===----------------------------------------------------------------------===//
718 // -Wuninitialized
719 //===----------------------------------------------------------------------===//
720 
721 namespace {
722 /// ContainsReference - A visitor class to search for references to
723 /// a particular declaration (the needle) within any evaluated component of an
724 /// expression (recursively).
725 class ContainsReference : public ConstEvaluatedExprVisitor<ContainsReference> {
726  bool FoundReference;
727  const DeclRefExpr *Needle;
728 
729 public:
731 
732  ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
733  : Inherited(Context), FoundReference(false), Needle(Needle) {}
734 
735  void VisitExpr(const Expr *E) {
736  // Stop evaluating if we already have a reference.
737  if (FoundReference)
738  return;
739 
740  Inherited::VisitExpr(E);
741  }
742 
743  void VisitDeclRefExpr(const DeclRefExpr *E) {
744  if (E == Needle)
745  FoundReference = true;
746  else
747  Inherited::VisitDeclRefExpr(E);
748  }
749 
750  bool doesContainReference() const { return FoundReference; }
751 };
752 } // anonymous namespace
753 
754 static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
755  QualType VariableTy = VD->getType().getCanonicalType();
756  if (VariableTy->isBlockPointerType() &&
757  !VD->hasAttr<BlocksAttr>()) {
758  S.Diag(VD->getLocation(), diag::note_block_var_fixit_add_initialization)
759  << VD->getDeclName()
760  << FixItHint::CreateInsertion(VD->getLocation(), "__block ");
761  return true;
762  }
763 
764  // Don't issue a fixit if there is already an initializer.
765  if (VD->getInit())
766  return false;
767 
768  // Don't suggest a fixit inside macros.
769  if (VD->getEndLoc().isMacroID())
770  return false;
771 
773 
774  // Suggest possible initialization (if any).
775  std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
776  if (Init.empty())
777  return false;
778 
779  S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName()
780  << FixItHint::CreateInsertion(Loc, Init);
781  return true;
782 }
783 
784 /// Create a fixit to remove an if-like statement, on the assumption that its
785 /// condition is CondVal.
786 static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then,
787  const Stmt *Else, bool CondVal,
788  FixItHint &Fixit1, FixItHint &Fixit2) {
789  if (CondVal) {
790  // If condition is always true, remove all but the 'then'.
791  Fixit1 = FixItHint::CreateRemoval(
793  if (Else) {
794  SourceLocation ElseKwLoc = S.getLocForEndOfToken(Then->getEndLoc());
795  Fixit2 =
796  FixItHint::CreateRemoval(SourceRange(ElseKwLoc, Else->getEndLoc()));
797  }
798  } else {
799  // If condition is always false, remove all but the 'else'.
800  if (Else)
802  If->getBeginLoc(), Else->getBeginLoc()));
803  else
805  }
806 }
807 
808 /// DiagUninitUse -- Helper function to produce a diagnostic for an
809 /// uninitialized use of a variable.
810 static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
811  bool IsCapturedByBlock) {
812  bool Diagnosed = false;
813 
814  switch (Use.getKind()) {
815  case UninitUse::Always:
816  S.Diag(Use.getUser()->getBeginLoc(), diag::warn_uninit_var)
817  << VD->getDeclName() << IsCapturedByBlock
818  << Use.getUser()->getSourceRange();
819  return;
820 
823  S.Diag(VD->getLocation(), diag::warn_sometimes_uninit_var)
824  << VD->getDeclName() << IsCapturedByBlock
825  << (Use.getKind() == UninitUse::AfterDecl ? 4 : 5)
826  << const_cast<DeclContext*>(VD->getLexicalDeclContext())
827  << VD->getSourceRange();
828  S.Diag(Use.getUser()->getBeginLoc(), diag::note_uninit_var_use)
829  << IsCapturedByBlock << Use.getUser()->getSourceRange();
830  return;
831 
832  case UninitUse::Maybe:
834  // Carry on to report sometimes-uninitialized branches, if possible,
835  // or a 'may be used uninitialized' diagnostic otherwise.
836  break;
837  }
838 
839  // Diagnose each branch which leads to a sometimes-uninitialized use.
840  for (UninitUse::branch_iterator I = Use.branch_begin(), E = Use.branch_end();
841  I != E; ++I) {
842  assert(Use.getKind() == UninitUse::Sometimes);
843 
844  const Expr *User = Use.getUser();
845  const Stmt *Term = I->Terminator;
846 
847  // Information used when building the diagnostic.
848  unsigned DiagKind;
849  StringRef Str;
850  SourceRange Range;
851 
852  // FixIts to suppress the diagnostic by removing the dead condition.
853  // For all binary terminators, branch 0 is taken if the condition is true,
854  // and branch 1 is taken if the condition is false.
855  int RemoveDiagKind = -1;
856  const char *FixitStr =
857  S.getLangOpts().CPlusPlus ? (I->Output ? "true" : "false")
858  : (I->Output ? "1" : "0");
859  FixItHint Fixit1, Fixit2;
860 
861  switch (Term ? Term->getStmtClass() : Stmt::DeclStmtClass) {
862  default:
863  // Don't know how to report this. Just fall back to 'may be used
864  // uninitialized'. FIXME: Can this happen?
865  continue;
866 
867  // "condition is true / condition is false".
868  case Stmt::IfStmtClass: {
869  const IfStmt *IS = cast<IfStmt>(Term);
870  DiagKind = 0;
871  Str = "if";
872  Range = IS->getCond()->getSourceRange();
873  RemoveDiagKind = 0;
874  CreateIfFixit(S, IS, IS->getThen(), IS->getElse(),
875  I->Output, Fixit1, Fixit2);
876  break;
877  }
878  case Stmt::ConditionalOperatorClass: {
879  const ConditionalOperator *CO = cast<ConditionalOperator>(Term);
880  DiagKind = 0;
881  Str = "?:";
882  Range = CO->getCond()->getSourceRange();
883  RemoveDiagKind = 0;
884  CreateIfFixit(S, CO, CO->getTrueExpr(), CO->getFalseExpr(),
885  I->Output, Fixit1, Fixit2);
886  break;
887  }
888  case Stmt::BinaryOperatorClass: {
889  const BinaryOperator *BO = cast<BinaryOperator>(Term);
890  if (!BO->isLogicalOp())
891  continue;
892  DiagKind = 0;
893  Str = BO->getOpcodeStr();
894  Range = BO->getLHS()->getSourceRange();
895  RemoveDiagKind = 0;
896  if ((BO->getOpcode() == BO_LAnd && I->Output) ||
897  (BO->getOpcode() == BO_LOr && !I->Output))
898  // true && y -> y, false || y -> y.
899  Fixit1 = FixItHint::CreateRemoval(
900  SourceRange(BO->getBeginLoc(), BO->getOperatorLoc()));
901  else
902  // false && y -> false, true || y -> true.
903  Fixit1 = FixItHint::CreateReplacement(BO->getSourceRange(), FixitStr);
904  break;
905  }
906 
907  // "loop is entered / loop is exited".
908  case Stmt::WhileStmtClass:
909  DiagKind = 1;
910  Str = "while";
911  Range = cast<WhileStmt>(Term)->getCond()->getSourceRange();
912  RemoveDiagKind = 1;
913  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
914  break;
915  case Stmt::ForStmtClass:
916  DiagKind = 1;
917  Str = "for";
918  Range = cast<ForStmt>(Term)->getCond()->getSourceRange();
919  RemoveDiagKind = 1;
920  if (I->Output)
921  Fixit1 = FixItHint::CreateRemoval(Range);
922  else
923  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
924  break;
925  case Stmt::CXXForRangeStmtClass:
926  if (I->Output == 1) {
927  // The use occurs if a range-based for loop's body never executes.
928  // That may be impossible, and there's no syntactic fix for this,
929  // so treat it as a 'may be uninitialized' case.
930  continue;
931  }
932  DiagKind = 1;
933  Str = "for";
934  Range = cast<CXXForRangeStmt>(Term)->getRangeInit()->getSourceRange();
935  break;
936 
937  // "condition is true / loop is exited".
938  case Stmt::DoStmtClass:
939  DiagKind = 2;
940  Str = "do";
941  Range = cast<DoStmt>(Term)->getCond()->getSourceRange();
942  RemoveDiagKind = 1;
943  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
944  break;
945 
946  // "switch case is taken".
947  case Stmt::CaseStmtClass:
948  DiagKind = 3;
949  Str = "case";
950  Range = cast<CaseStmt>(Term)->getLHS()->getSourceRange();
951  break;
952  case Stmt::DefaultStmtClass:
953  DiagKind = 3;
954  Str = "default";
955  Range = cast<DefaultStmt>(Term)->getDefaultLoc();
956  break;
957  }
958 
959  S.Diag(Range.getBegin(), diag::warn_sometimes_uninit_var)
960  << VD->getDeclName() << IsCapturedByBlock << DiagKind
961  << Str << I->Output << Range;
962  S.Diag(User->getBeginLoc(), diag::note_uninit_var_use)
963  << IsCapturedByBlock << User->getSourceRange();
964  if (RemoveDiagKind != -1)
965  S.Diag(Fixit1.RemoveRange.getBegin(), diag::note_uninit_fixit_remove_cond)
966  << RemoveDiagKind << Str << I->Output << Fixit1 << Fixit2;
967 
968  Diagnosed = true;
969  }
970 
971  if (!Diagnosed)
972  S.Diag(Use.getUser()->getBeginLoc(), diag::warn_maybe_uninit_var)
973  << VD->getDeclName() << IsCapturedByBlock
974  << Use.getUser()->getSourceRange();
975 }
976 
977 /// Diagnose uninitialized const reference usages.
979  const UninitUse &Use) {
980  S.Diag(Use.getUser()->getBeginLoc(), diag::warn_uninit_const_reference)
981  << VD->getDeclName() << Use.getUser()->getSourceRange();
982  return true;
983 }
984 
985 /// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
986 /// uninitialized variable. This manages the different forms of diagnostic
987 /// emitted for particular types of uses. Returns true if the use was diagnosed
988 /// as a warning. If a particular use is one we omit warnings for, returns
989 /// false.
990 static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
991  const UninitUse &Use,
992  bool alwaysReportSelfInit = false) {
993  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Use.getUser())) {
994  // Inspect the initializer of the variable declaration which is
995  // being referenced prior to its initialization. We emit
996  // specialized diagnostics for self-initialization, and we
997  // specifically avoid warning about self references which take the
998  // form of:
999  //
1000  // int x = x;
1001  //
1002  // This is used to indicate to GCC that 'x' is intentionally left
1003  // uninitialized. Proven code paths which access 'x' in
1004  // an uninitialized state after this will still warn.
1005  if (const Expr *Initializer = VD->getInit()) {
1006  if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
1007  return false;
1008 
1009  ContainsReference CR(S.Context, DRE);
1010  CR.Visit(Initializer);
1011  if (CR.doesContainReference()) {
1012  S.Diag(DRE->getBeginLoc(), diag::warn_uninit_self_reference_in_init)
1013  << VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
1014  return true;
1015  }
1016  }
1017 
1018  DiagUninitUse(S, VD, Use, false);
1019  } else {
1020  const BlockExpr *BE = cast<BlockExpr>(Use.getUser());
1021  if (VD->getType()->isBlockPointerType() && !VD->hasAttr<BlocksAttr>())
1022  S.Diag(BE->getBeginLoc(),
1023  diag::warn_uninit_byref_blockvar_captured_by_block)
1024  << VD->getDeclName()
1025  << VD->getType().getQualifiers().hasObjCLifetime();
1026  else
1027  DiagUninitUse(S, VD, Use, true);
1028  }
1029 
1030  // Report where the variable was declared when the use wasn't within
1031  // the initializer of that declaration & we didn't already suggest
1032  // an initialization fixit.
1033  if (!SuggestInitializationFixit(S, VD))
1034  S.Diag(VD->getBeginLoc(), diag::note_var_declared_here)
1035  << VD->getDeclName();
1036 
1037  return true;
1038 }
1039 
1040 namespace {
1041  class FallthroughMapper : public RecursiveASTVisitor<FallthroughMapper> {
1042  public:
1043  FallthroughMapper(Sema &S)
1044  : FoundSwitchStatements(false),
1045  S(S) {
1046  }
1047 
1048  bool foundSwitchStatements() const { return FoundSwitchStatements; }
1049 
1050  void markFallthroughVisited(const AttributedStmt *Stmt) {
1051  bool Found = FallthroughStmts.erase(Stmt);
1052  assert(Found);
1053  (void)Found;
1054  }
1055 
1057 
1058  const AttrStmts &getFallthroughStmts() const {
1059  return FallthroughStmts;
1060  }
1061 
1062  void fillReachableBlocks(CFG *Cfg) {
1063  assert(ReachableBlocks.empty() && "ReachableBlocks already filled");
1064  std::deque<const CFGBlock *> BlockQueue;
1065 
1066  ReachableBlocks.insert(&Cfg->getEntry());
1067  BlockQueue.push_back(&Cfg->getEntry());
1068  // Mark all case blocks reachable to avoid problems with switching on
1069  // constants, covered enums, etc.
1070  // These blocks can contain fall-through annotations, and we don't want to
1071  // issue a warn_fallthrough_attr_unreachable for them.
1072  for (const auto *B : *Cfg) {
1073  const Stmt *L = B->getLabel();
1074  if (L && isa<SwitchCase>(L) && ReachableBlocks.insert(B).second)
1075  BlockQueue.push_back(B);
1076  }
1077 
1078  while (!BlockQueue.empty()) {
1079  const CFGBlock *P = BlockQueue.front();
1080  BlockQueue.pop_front();
1082  E = P->succ_end();
1083  I != E; ++I) {
1084  if (*I && ReachableBlocks.insert(*I).second)
1085  BlockQueue.push_back(*I);
1086  }
1087  }
1088  }
1089 
1090  bool checkFallThroughIntoBlock(const CFGBlock &B, int &AnnotatedCnt,
1091  bool IsTemplateInstantiation) {
1092  assert(!ReachableBlocks.empty() && "ReachableBlocks empty");
1093 
1094  int UnannotatedCnt = 0;
1095  AnnotatedCnt = 0;
1096 
1097  std::deque<const CFGBlock*> BlockQueue(B.pred_begin(), B.pred_end());
1098  while (!BlockQueue.empty()) {
1099  const CFGBlock *P = BlockQueue.front();
1100  BlockQueue.pop_front();
1101  if (!P) continue;
1102 
1103  const Stmt *Term = P->getTerminatorStmt();
1104  if (Term && isa<SwitchStmt>(Term))
1105  continue; // Switch statement, good.
1106 
1107  const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(P->getLabel());
1108  if (SW && SW->getSubStmt() == B.getLabel() && P->begin() == P->end())
1109  continue; // Previous case label has no statements, good.
1110 
1111  const LabelStmt *L = dyn_cast_or_null<LabelStmt>(P->getLabel());
1112  if (L && L->getSubStmt() == B.getLabel() && P->begin() == P->end())
1113  continue; // Case label is preceded with a normal label, good.
1114 
1115  if (!ReachableBlocks.count(P)) {
1116  for (CFGBlock::const_reverse_iterator ElemIt = P->rbegin(),
1117  ElemEnd = P->rend();
1118  ElemIt != ElemEnd; ++ElemIt) {
1119  if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>()) {
1120  if (const AttributedStmt *AS = asFallThroughAttr(CS->getStmt())) {
1121  // Don't issue a warning for an unreachable fallthrough
1122  // attribute in template instantiations as it may not be
1123  // unreachable in all instantiations of the template.
1124  if (!IsTemplateInstantiation)
1125  S.Diag(AS->getBeginLoc(),
1126  diag::warn_fallthrough_attr_unreachable);
1127  markFallthroughVisited(AS);
1128  ++AnnotatedCnt;
1129  break;
1130  }
1131  // Don't care about other unreachable statements.
1132  }
1133  }
1134  // If there are no unreachable statements, this may be a special
1135  // case in CFG:
1136  // case X: {
1137  // A a; // A has a destructor.
1138  // break;
1139  // }
1140  // // <<<< This place is represented by a 'hanging' CFG block.
1141  // case Y:
1142  continue;
1143  }
1144 
1145  const Stmt *LastStmt = getLastStmt(*P);
1146  if (const AttributedStmt *AS = asFallThroughAttr(LastStmt)) {
1147  markFallthroughVisited(AS);
1148  ++AnnotatedCnt;
1149  continue; // Fallthrough annotation, good.
1150  }
1151 
1152  if (!LastStmt) { // This block contains no executable statements.
1153  // Traverse its predecessors.
1154  std::copy(P->pred_begin(), P->pred_end(),
1155  std::back_inserter(BlockQueue));
1156  continue;
1157  }
1158 
1159  ++UnannotatedCnt;
1160  }
1161  return !!UnannotatedCnt;
1162  }
1163 
1164  // RecursiveASTVisitor setup.
1165  bool shouldWalkTypesOfTypeLocs() const { return false; }
1166 
1167  bool VisitAttributedStmt(AttributedStmt *S) {
1168  if (asFallThroughAttr(S))
1169  FallthroughStmts.insert(S);
1170  return true;
1171  }
1172 
1173  bool VisitSwitchStmt(SwitchStmt *S) {
1174  FoundSwitchStatements = true;
1175  return true;
1176  }
1177 
1178  // We don't want to traverse local type declarations. We analyze their
1179  // methods separately.
1180  bool TraverseDecl(Decl *D) { return true; }
1181 
1182  // We analyze lambda bodies separately. Skip them here.
1183  bool TraverseLambdaExpr(LambdaExpr *LE) {
1184  // Traverse the captures, but not the body.
1185  for (const auto C : zip(LE->captures(), LE->capture_inits()))
1186  TraverseLambdaCapture(LE, &std::get<0>(C), std::get<1>(C));
1187  return true;
1188  }
1189 
1190  private:
1191 
1192  static const AttributedStmt *asFallThroughAttr(const Stmt *S) {
1193  if (const AttributedStmt *AS = dyn_cast_or_null<AttributedStmt>(S)) {
1194  if (hasSpecificAttr<FallThroughAttr>(AS->getAttrs()))
1195  return AS;
1196  }
1197  return nullptr;
1198  }
1199 
1200  static const Stmt *getLastStmt(const CFGBlock &B) {
1201  if (const Stmt *Term = B.getTerminatorStmt())
1202  return Term;
1203  for (CFGBlock::const_reverse_iterator ElemIt = B.rbegin(),
1204  ElemEnd = B.rend();
1205  ElemIt != ElemEnd; ++ElemIt) {
1206  if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>())
1207  return CS->getStmt();
1208  }
1209  // Workaround to detect a statement thrown out by CFGBuilder:
1210  // case X: {} case Y:
1211  // case X: ; case Y:
1212  if (const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(B.getLabel()))
1213  if (!isa<SwitchCase>(SW->getSubStmt()))
1214  return SW->getSubStmt();
1215 
1216  return nullptr;
1217  }
1218 
1219  bool FoundSwitchStatements;
1220  AttrStmts FallthroughStmts;
1221  Sema &S;
1223  };
1224 } // anonymous namespace
1225 
1227  SourceLocation Loc) {
1228  TokenValue FallthroughTokens[] = {
1229  tok::l_square, tok::l_square,
1230  PP.getIdentifierInfo("fallthrough"),
1231  tok::r_square, tok::r_square
1232  };
1233 
1234  TokenValue ClangFallthroughTokens[] = {
1235  tok::l_square, tok::l_square, PP.getIdentifierInfo("clang"),
1236  tok::coloncolon, PP.getIdentifierInfo("fallthrough"),
1237  tok::r_square, tok::r_square
1238  };
1239 
1240  bool PreferClangAttr = !PP.getLangOpts().CPlusPlus17 && !PP.getLangOpts().C2x;
1241 
1242  StringRef MacroName;
1243  if (PreferClangAttr)
1244  MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
1245  if (MacroName.empty())
1246  MacroName = PP.getLastMacroWithSpelling(Loc, FallthroughTokens);
1247  if (MacroName.empty() && !PreferClangAttr)
1248  MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
1249  if (MacroName.empty()) {
1250  if (!PreferClangAttr)
1251  MacroName = "[[fallthrough]]";
1252  else if (PP.getLangOpts().CPlusPlus)
1253  MacroName = "[[clang::fallthrough]]";
1254  else
1255  MacroName = "__attribute__((fallthrough))";
1256  }
1257  return MacroName;
1258 }
1259 
1261  bool PerFunction) {
1262  FallthroughMapper FM(S);
1263  FM.TraverseStmt(AC.getBody());
1264 
1265  if (!FM.foundSwitchStatements())
1266  return;
1267 
1268  if (PerFunction && FM.getFallthroughStmts().empty())
1269  return;
1270 
1271  CFG *Cfg = AC.getCFG();
1272 
1273  if (!Cfg)
1274  return;
1275 
1276  FM.fillReachableBlocks(Cfg);
1277 
1278  for (const CFGBlock *B : llvm::reverse(*Cfg)) {
1279  const Stmt *Label = B->getLabel();
1280 
1281  if (!Label || !isa<SwitchCase>(Label))
1282  continue;
1283 
1284  int AnnotatedCnt;
1285 
1286  bool IsTemplateInstantiation = false;
1287  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(AC.getDecl()))
1288  IsTemplateInstantiation = Function->isTemplateInstantiation();
1289  if (!FM.checkFallThroughIntoBlock(*B, AnnotatedCnt,
1290  IsTemplateInstantiation))
1291  continue;
1292 
1293  S.Diag(Label->getBeginLoc(),
1294  PerFunction ? diag::warn_unannotated_fallthrough_per_function
1295  : diag::warn_unannotated_fallthrough);
1296 
1297  if (!AnnotatedCnt) {
1298  SourceLocation L = Label->getBeginLoc();
1299  if (L.isMacroID())
1300  continue;
1301 
1302  const Stmt *Term = B->getTerminatorStmt();
1303  // Skip empty cases.
1304  while (B->empty() && !Term && B->succ_size() == 1) {
1305  B = *B->succ_begin();
1306  Term = B->getTerminatorStmt();
1307  }
1308  if (!(B->empty() && Term && isa<BreakStmt>(Term))) {
1309  Preprocessor &PP = S.getPreprocessor();
1310  StringRef AnnotationSpelling = getFallthroughAttrSpelling(PP, L);
1311  SmallString<64> TextToInsert(AnnotationSpelling);
1312  TextToInsert += "; ";
1313  S.Diag(L, diag::note_insert_fallthrough_fixit)
1314  << AnnotationSpelling
1315  << FixItHint::CreateInsertion(L, TextToInsert);
1316  }
1317  S.Diag(L, diag::note_insert_break_fixit)
1318  << FixItHint::CreateInsertion(L, "break; ");
1319  }
1320  }
1321 
1322  for (const auto *F : FM.getFallthroughStmts())
1323  S.Diag(F->getBeginLoc(), diag::err_fallthrough_attr_invalid_placement);
1324 }
1325 
1326 static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM,
1327  const Stmt *S) {
1328  assert(S);
1329 
1330  do {
1331  switch (S->getStmtClass()) {
1332  case Stmt::ForStmtClass:
1333  case Stmt::WhileStmtClass:
1334  case Stmt::CXXForRangeStmtClass:
1335  case Stmt::ObjCForCollectionStmtClass:
1336  return true;
1337  case Stmt::DoStmtClass: {
1339  if (!cast<DoStmt>(S)->getCond()->EvaluateAsInt(Result, Ctx))
1340  return true;
1341  return Result.Val.getInt().getBoolValue();
1342  }
1343  default:
1344  break;
1345  }
1346  } while ((S = PM.getParent(S)));
1347 
1348  return false;
1349 }
1350 
1352  const sema::FunctionScopeInfo *CurFn,
1353  const Decl *D,
1354  const ParentMap &PM) {
1355  typedef sema::FunctionScopeInfo::WeakObjectProfileTy WeakObjectProfileTy;
1356  typedef sema::FunctionScopeInfo::WeakObjectUseMap WeakObjectUseMap;
1357  typedef sema::FunctionScopeInfo::WeakUseVector WeakUseVector;
1358  typedef std::pair<const Stmt *, WeakObjectUseMap::const_iterator>
1359  StmtUsesPair;
1360 
1361  ASTContext &Ctx = S.getASTContext();
1362 
1363  const WeakObjectUseMap &WeakMap = CurFn->getWeakObjectUses();
1364 
1365  // Extract all weak objects that are referenced more than once.
1366  SmallVector<StmtUsesPair, 8> UsesByStmt;
1367  for (WeakObjectUseMap::const_iterator I = WeakMap.begin(), E = WeakMap.end();
1368  I != E; ++I) {
1369  const WeakUseVector &Uses = I->second;
1370 
1371  // Find the first read of the weak object.
1372  WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
1373  for ( ; UI != UE; ++UI) {
1374  if (UI->isUnsafe())
1375  break;
1376  }
1377 
1378  // If there were only writes to this object, don't warn.
1379  if (UI == UE)
1380  continue;
1381 
1382  // If there was only one read, followed by any number of writes, and the
1383  // read is not within a loop, don't warn. Additionally, don't warn in a
1384  // loop if the base object is a local variable -- local variables are often
1385  // changed in loops.
1386  if (UI == Uses.begin()) {
1387  WeakUseVector::const_iterator UI2 = UI;
1388  for (++UI2; UI2 != UE; ++UI2)
1389  if (UI2->isUnsafe())
1390  break;
1391 
1392  if (UI2 == UE) {
1393  if (!isInLoop(Ctx, PM, UI->getUseExpr()))
1394  continue;
1395 
1396  const WeakObjectProfileTy &Profile = I->first;
1397  if (!Profile.isExactProfile())
1398  continue;
1399 
1400  const NamedDecl *Base = Profile.getBase();
1401  if (!Base)
1402  Base = Profile.getProperty();
1403  assert(Base && "A profile always has a base or property.");
1404 
1405  if (const VarDecl *BaseVar = dyn_cast<VarDecl>(Base))
1406  if (BaseVar->hasLocalStorage() && !isa<ParmVarDecl>(Base))
1407  continue;
1408  }
1409  }
1410 
1411  UsesByStmt.push_back(StmtUsesPair(UI->getUseExpr(), I));
1412  }
1413 
1414  if (UsesByStmt.empty())
1415  return;
1416 
1417  // Sort by first use so that we emit the warnings in a deterministic order.
1419  llvm::sort(UsesByStmt,
1420  [&SM](const StmtUsesPair &LHS, const StmtUsesPair &RHS) {
1421  return SM.isBeforeInTranslationUnit(LHS.first->getBeginLoc(),
1422  RHS.first->getBeginLoc());
1423  });
1424 
1425  // Classify the current code body for better warning text.
1426  // This enum should stay in sync with the cases in
1427  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1428  // FIXME: Should we use a common classification enum and the same set of
1429  // possibilities all throughout Sema?
1430  enum {
1431  Function,
1432  Method,
1433  Block,
1434  Lambda
1435  } FunctionKind;
1436 
1437  if (isa<sema::BlockScopeInfo>(CurFn))
1438  FunctionKind = Block;
1439  else if (isa<sema::LambdaScopeInfo>(CurFn))
1440  FunctionKind = Lambda;
1441  else if (isa<ObjCMethodDecl>(D))
1442  FunctionKind = Method;
1443  else
1444  FunctionKind = Function;
1445 
1446  // Iterate through the sorted problems and emit warnings for each.
1447  for (const auto &P : UsesByStmt) {
1448  const Stmt *FirstRead = P.first;
1449  const WeakObjectProfileTy &Key = P.second->first;
1450  const WeakUseVector &Uses = P.second->second;
1451 
1452  // For complicated expressions like 'a.b.c' and 'x.b.c', WeakObjectProfileTy
1453  // may not contain enough information to determine that these are different
1454  // properties. We can only be 100% sure of a repeated use in certain cases,
1455  // and we adjust the diagnostic kind accordingly so that the less certain
1456  // case can be turned off if it is too noisy.
1457  unsigned DiagKind;
1458  if (Key.isExactProfile())
1459  DiagKind = diag::warn_arc_repeated_use_of_weak;
1460  else
1461  DiagKind = diag::warn_arc_possible_repeated_use_of_weak;
1462 
1463  // Classify the weak object being accessed for better warning text.
1464  // This enum should stay in sync with the cases in
1465  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1466  enum {
1467  Variable,
1468  Property,
1469  ImplicitProperty,
1470  Ivar
1471  } ObjectKind;
1472 
1473  const NamedDecl *KeyProp = Key.getProperty();
1474  if (isa<VarDecl>(KeyProp))
1475  ObjectKind = Variable;
1476  else if (isa<ObjCPropertyDecl>(KeyProp))
1477  ObjectKind = Property;
1478  else if (isa<ObjCMethodDecl>(KeyProp))
1479  ObjectKind = ImplicitProperty;
1480  else if (isa<ObjCIvarDecl>(KeyProp))
1481  ObjectKind = Ivar;
1482  else
1483  llvm_unreachable("Unexpected weak object kind!");
1484 
1485  // Do not warn about IBOutlet weak property receivers being set to null
1486  // since they are typically only used from the main thread.
1487  if (const ObjCPropertyDecl *Prop = dyn_cast<ObjCPropertyDecl>(KeyProp))
1488  if (Prop->hasAttr<IBOutletAttr>())
1489  continue;
1490 
1491  // Show the first time the object was read.
1492  S.Diag(FirstRead->getBeginLoc(), DiagKind)
1493  << int(ObjectKind) << KeyProp << int(FunctionKind)
1494  << FirstRead->getSourceRange();
1495 
1496  // Print all the other accesses as notes.
1497  for (const auto &Use : Uses) {
1498  if (Use.getUseExpr() == FirstRead)
1499  continue;
1500  S.Diag(Use.getUseExpr()->getBeginLoc(),
1501  diag::note_arc_weak_also_accessed_here)
1502  << Use.getUseExpr()->getSourceRange();
1503  }
1504  }
1505 }
1506 
1507 namespace {
1508 class UninitValsDiagReporter : public UninitVariablesHandler {
1509  Sema &S;
1510  typedef SmallVector<UninitUse, 2> UsesVec;
1511  typedef llvm::PointerIntPair<UsesVec *, 1, bool> MappedType;
1512  // Prefer using MapVector to DenseMap, so that iteration order will be
1513  // the same as insertion order. This is needed to obtain a deterministic
1514  // order of diagnostics when calling flushDiagnostics().
1515  typedef llvm::MapVector<const VarDecl *, MappedType> UsesMap;
1516  UsesMap uses;
1517  UsesMap constRefUses;
1518 
1519 public:
1520  UninitValsDiagReporter(Sema &S) : S(S) {}
1521  ~UninitValsDiagReporter() override { flushDiagnostics(); }
1522 
1523  MappedType &getUses(UsesMap &um, const VarDecl *vd) {
1524  MappedType &V = um[vd];
1525  if (!V.getPointer())
1526  V.setPointer(new UsesVec());
1527  return V;
1528  }
1529 
1530  void handleUseOfUninitVariable(const VarDecl *vd,
1531  const UninitUse &use) override {
1532  getUses(uses, vd).getPointer()->push_back(use);
1533  }
1534 
1535  void handleConstRefUseOfUninitVariable(const VarDecl *vd,
1536  const UninitUse &use) override {
1537  getUses(constRefUses, vd).getPointer()->push_back(use);
1538  }
1539 
1540  void handleSelfInit(const VarDecl *vd) override {
1541  getUses(uses, vd).setInt(true);
1542  getUses(constRefUses, vd).setInt(true);
1543  }
1544 
1545  void flushDiagnostics() {
1546  for (const auto &P : uses) {
1547  const VarDecl *vd = P.first;
1548  const MappedType &V = P.second;
1549 
1550  UsesVec *vec = V.getPointer();
1551  bool hasSelfInit = V.getInt();
1552 
1553  // Specially handle the case where we have uses of an uninitialized
1554  // variable, but the root cause is an idiomatic self-init. We want
1555  // to report the diagnostic at the self-init since that is the root cause.
1556  if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
1559  /* isAlwaysUninit */ true),
1560  /* alwaysReportSelfInit */ true);
1561  else {
1562  // Sort the uses by their SourceLocations. While not strictly
1563  // guaranteed to produce them in line/column order, this will provide
1564  // a stable ordering.
1565  llvm::sort(vec->begin(), vec->end(),
1566  [](const UninitUse &a, const UninitUse &b) {
1567  // Prefer a more confident report over a less confident one.
1568  if (a.getKind() != b.getKind())
1569  return a.getKind() > b.getKind();
1570  return a.getUser()->getBeginLoc() < b.getUser()->getBeginLoc();
1571  });
1572 
1573  for (const auto &U : *vec) {
1574  // If we have self-init, downgrade all uses to 'may be uninitialized'.
1575  UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
1576 
1577  if (DiagnoseUninitializedUse(S, vd, Use))
1578  // Skip further diagnostics for this variable. We try to warn only
1579  // on the first point at which a variable is used uninitialized.
1580  break;
1581  }
1582  }
1583 
1584  // Release the uses vector.
1585  delete vec;
1586  }
1587 
1588  uses.clear();
1589 
1590  // Flush all const reference uses diags.
1591  for (const auto &P : constRefUses) {
1592  const VarDecl *vd = P.first;
1593  const MappedType &V = P.second;
1594 
1595  UsesVec *vec = V.getPointer();
1596  bool hasSelfInit = V.getInt();
1597 
1598  if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
1601  /* isAlwaysUninit */ true),
1602  /* alwaysReportSelfInit */ true);
1603  else {
1604  for (const auto &U : *vec) {
1605  if (DiagnoseUninitializedConstRefUse(S, vd, U))
1606  break;
1607  }
1608  }
1609 
1610  // Release the uses vector.
1611  delete vec;
1612  }
1613 
1614  constRefUses.clear();
1615  }
1616 
1617 private:
1618  static bool hasAlwaysUninitializedUse(const UsesVec* vec) {
1619  return std::any_of(vec->begin(), vec->end(), [](const UninitUse &U) {
1620  return U.getKind() == UninitUse::Always ||
1621  U.getKind() == UninitUse::AfterCall ||
1622  U.getKind() == UninitUse::AfterDecl;
1623  });
1624  }
1625 };
1626 } // anonymous namespace
1627 
1628 namespace clang {
1629 namespace {
1631 typedef std::pair<PartialDiagnosticAt, OptionalNotes> DelayedDiag;
1632 typedef std::list<DelayedDiag> DiagList;
1633 
1634 struct SortDiagBySourceLocation {
1636  SortDiagBySourceLocation(SourceManager &SM) : SM(SM) {}
1637 
1638  bool operator()(const DelayedDiag &left, const DelayedDiag &right) {
1639  // Although this call will be slow, this is only called when outputting
1640  // multiple warnings.
1641  return SM.isBeforeInTranslationUnit(left.first.first, right.first.first);
1642  }
1643 };
1644 } // anonymous namespace
1645 } // namespace clang
1646 
1647 //===----------------------------------------------------------------------===//
1648 // -Wthread-safety
1649 //===----------------------------------------------------------------------===//
1650 namespace clang {
1651 namespace threadSafety {
1652 namespace {
1653 class ThreadSafetyReporter : public clang::threadSafety::ThreadSafetyHandler {
1654  Sema &S;
1655  DiagList Warnings;
1656  SourceLocation FunLocation, FunEndLocation;
1657 
1658  const FunctionDecl *CurrentFunction;
1659  bool Verbose;
1660 
1661  OptionalNotes getNotes() const {
1662  if (Verbose && CurrentFunction) {
1663  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
1664  S.PDiag(diag::note_thread_warning_in_fun)
1665  << CurrentFunction);
1666  return OptionalNotes(1, FNote);
1667  }
1668  return OptionalNotes();
1669  }
1670 
1671  OptionalNotes getNotes(const PartialDiagnosticAt &Note) const {
1672  OptionalNotes ONS(1, Note);
1673  if (Verbose && CurrentFunction) {
1674  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
1675  S.PDiag(diag::note_thread_warning_in_fun)
1676  << CurrentFunction);
1677  ONS.push_back(std::move(FNote));
1678  }
1679  return ONS;
1680  }
1681 
1682  OptionalNotes getNotes(const PartialDiagnosticAt &Note1,
1683  const PartialDiagnosticAt &Note2) const {
1684  OptionalNotes ONS;
1685  ONS.push_back(Note1);
1686  ONS.push_back(Note2);
1687  if (Verbose && CurrentFunction) {
1688  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
1689  S.PDiag(diag::note_thread_warning_in_fun)
1690  << CurrentFunction);
1691  ONS.push_back(std::move(FNote));
1692  }
1693  return ONS;
1694  }
1695 
1696  OptionalNotes makeLockedHereNote(SourceLocation LocLocked, StringRef Kind) {
1697  return LocLocked.isValid()
1698  ? getNotes(PartialDiagnosticAt(
1699  LocLocked, S.PDiag(diag::note_locked_here) << Kind))
1700  : getNotes();
1701  }
1702 
1703  OptionalNotes makeUnlockedHereNote(SourceLocation LocUnlocked,
1704  StringRef Kind) {
1705  return LocUnlocked.isValid()
1706  ? getNotes(PartialDiagnosticAt(
1707  LocUnlocked, S.PDiag(diag::note_unlocked_here) << Kind))
1708  : getNotes();
1709  }
1710 
1711  public:
1712  ThreadSafetyReporter(Sema &S, SourceLocation FL, SourceLocation FEL)
1713  : S(S), FunLocation(FL), FunEndLocation(FEL),
1714  CurrentFunction(nullptr), Verbose(false) {}
1715 
1716  void setVerbose(bool b) { Verbose = b; }
1717 
1718  /// Emit all buffered diagnostics in order of sourcelocation.
1719  /// We need to output diagnostics produced while iterating through
1720  /// the lockset in deterministic order, so this function orders diagnostics
1721  /// and outputs them.
1722  void emitDiagnostics() {
1723  Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1724  for (const auto &Diag : Warnings) {
1725  S.Diag(Diag.first.first, Diag.first.second);
1726  for (const auto &Note : Diag.second)
1727  S.Diag(Note.first, Note.second);
1728  }
1729  }
1730 
1731  void handleInvalidLockExp(StringRef Kind, SourceLocation Loc) override {
1732  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_cannot_resolve_lock)
1733  << Loc);
1734  Warnings.emplace_back(std::move(Warning), getNotes());
1735  }
1736 
1737  void handleUnmatchedUnlock(StringRef Kind, Name LockName, SourceLocation Loc,
1738  SourceLocation LocPreviousUnlock) override {
1739  if (Loc.isInvalid())
1740  Loc = FunLocation;
1741  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_unlock_but_no_lock)
1742  << Kind << LockName);
1743  Warnings.emplace_back(std::move(Warning),
1744  makeUnlockedHereNote(LocPreviousUnlock, Kind));
1745  }
1746 
1747  void handleIncorrectUnlockKind(StringRef Kind, Name LockName,
1748  LockKind Expected, LockKind Received,
1749  SourceLocation LocLocked,
1750  SourceLocation LocUnlock) override {
1751  if (LocUnlock.isInvalid())
1752  LocUnlock = FunLocation;
1754  LocUnlock, S.PDiag(diag::warn_unlock_kind_mismatch)
1755  << Kind << LockName << Received << Expected);
1756  Warnings.emplace_back(std::move(Warning),
1757  makeLockedHereNote(LocLocked, Kind));
1758  }
1759 
1760  void handleDoubleLock(StringRef Kind, Name LockName, SourceLocation LocLocked,
1761  SourceLocation LocDoubleLock) override {
1762  if (LocDoubleLock.isInvalid())
1763  LocDoubleLock = FunLocation;
1764  PartialDiagnosticAt Warning(LocDoubleLock, S.PDiag(diag::warn_double_lock)
1765  << Kind << LockName);
1766  Warnings.emplace_back(std::move(Warning),
1767  makeLockedHereNote(LocLocked, Kind));
1768  }
1769 
1770  void handleMutexHeldEndOfScope(StringRef Kind, Name LockName,
1771  SourceLocation LocLocked,
1772  SourceLocation LocEndOfScope,
1773  LockErrorKind LEK) override {
1774  unsigned DiagID = 0;
1775  switch (LEK) {
1777  DiagID = diag::warn_lock_some_predecessors;
1778  break;
1780  DiagID = diag::warn_expecting_lock_held_on_loop;
1781  break;
1783  DiagID = diag::warn_no_unlock;
1784  break;
1786  DiagID = diag::warn_expecting_locked;
1787  break;
1788  }
1789  if (LocEndOfScope.isInvalid())
1790  LocEndOfScope = FunEndLocation;
1791 
1792  PartialDiagnosticAt Warning(LocEndOfScope, S.PDiag(DiagID) << Kind
1793  << LockName);
1794  Warnings.emplace_back(std::move(Warning),
1795  makeLockedHereNote(LocLocked, Kind));
1796  }
1797 
1798  void handleExclusiveAndShared(StringRef Kind, Name LockName,
1799  SourceLocation Loc1,
1800  SourceLocation Loc2) override {
1802  S.PDiag(diag::warn_lock_exclusive_and_shared)
1803  << Kind << LockName);
1804  PartialDiagnosticAt Note(Loc2, S.PDiag(diag::note_lock_exclusive_and_shared)
1805  << Kind << LockName);
1806  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1807  }
1808 
1809  void handleNoMutexHeld(StringRef Kind, const NamedDecl *D,
1811  SourceLocation Loc) override {
1812  assert((POK == POK_VarAccess || POK == POK_VarDereference) &&
1813  "Only works for variables");
1814  unsigned DiagID = POK == POK_VarAccess?
1815  diag::warn_variable_requires_any_lock:
1816  diag::warn_var_deref_requires_any_lock;
1817  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
1818  << D << getLockKindFromAccessKind(AK));
1819  Warnings.emplace_back(std::move(Warning), getNotes());
1820  }
1821 
1822  void handleMutexNotHeld(StringRef Kind, const NamedDecl *D,
1823  ProtectedOperationKind POK, Name LockName,
1824  LockKind LK, SourceLocation Loc,
1825  Name *PossibleMatch) override {
1826  unsigned DiagID = 0;
1827  if (PossibleMatch) {
1828  switch (POK) {
1829  case POK_VarAccess:
1830  DiagID = diag::warn_variable_requires_lock_precise;
1831  break;
1832  case POK_VarDereference:
1833  DiagID = diag::warn_var_deref_requires_lock_precise;
1834  break;
1835  case POK_FunctionCall:
1836  DiagID = diag::warn_fun_requires_lock_precise;
1837  break;
1838  case POK_PassByRef:
1839  DiagID = diag::warn_guarded_pass_by_reference;
1840  break;
1841  case POK_PtPassByRef:
1842  DiagID = diag::warn_pt_guarded_pass_by_reference;
1843  break;
1844  }
1845  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
1846  << D
1847  << LockName << LK);
1848  PartialDiagnosticAt Note(Loc, S.PDiag(diag::note_found_mutex_near_match)
1849  << *PossibleMatch);
1850  if (Verbose && POK == POK_VarAccess) {
1851  PartialDiagnosticAt VNote(D->getLocation(),
1852  S.PDiag(diag::note_guarded_by_declared_here)
1853  << D->getNameAsString());
1854  Warnings.emplace_back(std::move(Warning), getNotes(Note, VNote));
1855  } else
1856  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1857  } else {
1858  switch (POK) {
1859  case POK_VarAccess:
1860  DiagID = diag::warn_variable_requires_lock;
1861  break;
1862  case POK_VarDereference:
1863  DiagID = diag::warn_var_deref_requires_lock;
1864  break;
1865  case POK_FunctionCall:
1866  DiagID = diag::warn_fun_requires_lock;
1867  break;
1868  case POK_PassByRef:
1869  DiagID = diag::warn_guarded_pass_by_reference;
1870  break;
1871  case POK_PtPassByRef:
1872  DiagID = diag::warn_pt_guarded_pass_by_reference;
1873  break;
1874  }
1875  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
1876  << D
1877  << LockName << LK);
1878  if (Verbose && POK == POK_VarAccess) {
1880  S.PDiag(diag::note_guarded_by_declared_here));
1881  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1882  } else
1883  Warnings.emplace_back(std::move(Warning), getNotes());
1884  }
1885  }
1886 
1887  void handleNegativeNotHeld(StringRef Kind, Name LockName, Name Neg,
1888  SourceLocation Loc) override {
1890  S.PDiag(diag::warn_acquire_requires_negative_cap)
1891  << Kind << LockName << Neg);
1892  Warnings.emplace_back(std::move(Warning), getNotes());
1893  }
1894 
1895  void handleFunExcludesLock(StringRef Kind, Name FunName, Name LockName,
1896  SourceLocation Loc) override {
1897  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_fun_excludes_mutex)
1898  << Kind << FunName << LockName);
1899  Warnings.emplace_back(std::move(Warning), getNotes());
1900  }
1901 
1902  void handleLockAcquiredBefore(StringRef Kind, Name L1Name, Name L2Name,
1903  SourceLocation Loc) override {
1905  S.PDiag(diag::warn_acquired_before) << Kind << L1Name << L2Name);
1906  Warnings.emplace_back(std::move(Warning), getNotes());
1907  }
1908 
1909  void handleBeforeAfterCycle(Name L1Name, SourceLocation Loc) override {
1911  S.PDiag(diag::warn_acquired_before_after_cycle) << L1Name);
1912  Warnings.emplace_back(std::move(Warning), getNotes());
1913  }
1914 
1915  void enterFunction(const FunctionDecl* FD) override {
1916  CurrentFunction = FD;
1917  }
1918 
1919  void leaveFunction(const FunctionDecl* FD) override {
1920  CurrentFunction = nullptr;
1921  }
1922 };
1923 } // anonymous namespace
1924 } // namespace threadSafety
1925 } // namespace clang
1926 
1927 //===----------------------------------------------------------------------===//
1928 // -Wconsumed
1929 //===----------------------------------------------------------------------===//
1930 
1931 namespace clang {
1932 namespace consumed {
1933 namespace {
1934 class ConsumedWarningsHandler : public ConsumedWarningsHandlerBase {
1935 
1936  Sema &S;
1937  DiagList Warnings;
1938 
1939 public:
1940 
1941  ConsumedWarningsHandler(Sema &S) : S(S) {}
1942 
1943  void emitDiagnostics() override {
1944  Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1945  for (const auto &Diag : Warnings) {
1946  S.Diag(Diag.first.first, Diag.first.second);
1947  for (const auto &Note : Diag.second)
1948  S.Diag(Note.first, Note.second);
1949  }
1950  }
1951 
1952  void warnLoopStateMismatch(SourceLocation Loc,
1953  StringRef VariableName) override {
1954  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_loop_state_mismatch) <<
1955  VariableName);
1956 
1957  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1958  }
1959 
1960  void warnParamReturnTypestateMismatch(SourceLocation Loc,
1961  StringRef VariableName,
1962  StringRef ExpectedState,
1963  StringRef ObservedState) override {
1964 
1966  diag::warn_param_return_typestate_mismatch) << VariableName <<
1967  ExpectedState << ObservedState);
1968 
1969  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1970  }
1971 
1972  void warnParamTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
1973  StringRef ObservedState) override {
1974 
1976  diag::warn_param_typestate_mismatch) << ExpectedState << ObservedState);
1977 
1978  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1979  }
1980 
1981  void warnReturnTypestateForUnconsumableType(SourceLocation Loc,
1982  StringRef TypeName) override {
1984  diag::warn_return_typestate_for_unconsumable_type) << TypeName);
1985 
1986  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1987  }
1988 
1989  void warnReturnTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
1990  StringRef ObservedState) override {
1991 
1993  diag::warn_return_typestate_mismatch) << ExpectedState << ObservedState);
1994 
1995  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1996  }
1997 
1998  void warnUseOfTempInInvalidState(StringRef MethodName, StringRef State,
1999  SourceLocation Loc) override {
2000 
2002  diag::warn_use_of_temp_in_invalid_state) << MethodName << State);
2003 
2004  Warnings.emplace_back(std::move(Warning), OptionalNotes());
2005  }
2006 
2007  void warnUseInInvalidState(StringRef MethodName, StringRef VariableName,
2008  StringRef State, SourceLocation Loc) override {
2009 
2010  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_use_in_invalid_state) <<
2011  MethodName << VariableName << State);
2012 
2013  Warnings.emplace_back(std::move(Warning), OptionalNotes());
2014  }
2015 };
2016 } // anonymous namespace
2017 } // namespace consumed
2018 } // namespace clang
2019 
2020 //===----------------------------------------------------------------------===//
2021 // AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
2022 // warnings on a function, method, or block.
2023 //===----------------------------------------------------------------------===//
2024 
2026  enableCheckFallThrough = 1;
2027  enableCheckUnreachable = 0;
2028  enableThreadSafetyAnalysis = 0;
2029  enableConsumedAnalysis = 0;
2030 }
2031 
2032 static unsigned isEnabled(DiagnosticsEngine &D, unsigned diag) {
2033  return (unsigned)!D.isIgnored(diag, SourceLocation());
2034 }
2035 
2037  : S(s),
2038  NumFunctionsAnalyzed(0),
2039  NumFunctionsWithBadCFGs(0),
2040  NumCFGBlocks(0),
2041  MaxCFGBlocksPerFunction(0),
2042  NumUninitAnalysisFunctions(0),
2043  NumUninitAnalysisVariables(0),
2044  MaxUninitAnalysisVariablesPerFunction(0),
2045  NumUninitAnalysisBlockVisits(0),
2046  MaxUninitAnalysisBlockVisitsPerFunction(0) {
2047 
2048  using namespace diag;
2050 
2051  DefaultPolicy.enableCheckUnreachable =
2052  isEnabled(D, warn_unreachable) ||
2053  isEnabled(D, warn_unreachable_break) ||
2054  isEnabled(D, warn_unreachable_return) ||
2055  isEnabled(D, warn_unreachable_loop_increment);
2056 
2057  DefaultPolicy.enableThreadSafetyAnalysis =
2058  isEnabled(D, warn_double_lock);
2059 
2060  DefaultPolicy.enableConsumedAnalysis =
2061  isEnabled(D, warn_use_in_invalid_state);
2062 }
2063 
2064 static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope) {
2065  for (const auto &D : fscope->PossiblyUnreachableDiags)
2066  S.Diag(D.Loc, D.PD);
2067 }
2068 
2069 void clang::sema::
2071  sema::FunctionScopeInfo *fscope,
2072  const Decl *D, QualType BlockType) {
2073 
2074  // We avoid doing analysis-based warnings when there are errors for
2075  // two reasons:
2076  // (1) The CFGs often can't be constructed (if the body is invalid), so
2077  // don't bother trying.
2078  // (2) The code already has problems; running the analysis just takes more
2079  // time.
2080  DiagnosticsEngine &Diags = S.getDiagnostics();
2081 
2082  // Do not do any analysis if we are going to just ignore them.
2083  if (Diags.getIgnoreAllWarnings() ||
2084  (Diags.getSuppressSystemWarnings() &&
2086  return;
2087 
2088  // For code in dependent contexts, we'll do this at instantiation time.
2089  if (cast<DeclContext>(D)->isDependentContext())
2090  return;
2091 
2092  if (Diags.hasUncompilableErrorOccurred()) {
2093  // Flush out any possibly unreachable diagnostics.
2094  flushDiagnostics(S, fscope);
2095  return;
2096  }
2097 
2098  const Stmt *Body = D->getBody();
2099  assert(Body);
2100 
2101  // Construct the analysis context with the specified CFG build options.
2102  AnalysisDeclContext AC(/* AnalysisDeclContextManager */ nullptr, D);
2103 
2104  // Don't generate EH edges for CallExprs as we'd like to avoid the n^2
2105  // explosion for destructors that can result and the compile time hit.
2107  AC.getCFGBuildOptions().AddEHEdges = false;
2108  AC.getCFGBuildOptions().AddInitializers = true;
2113 
2114  // Force that certain expressions appear as CFGElements in the CFG. This
2115  // is used to speed up various analyses.
2116  // FIXME: This isn't the right factoring. This is here for initial
2117  // prototyping, but we need a way for analyses to say what expressions they
2118  // expect to always be CFGElements and then fill in the BuildOptions
2119  // appropriately. This is essentially a layering violation.
2120  if (P.enableCheckUnreachable || P.enableThreadSafetyAnalysis ||
2121  P.enableConsumedAnalysis) {
2122  // Unreachable code analysis and thread safety require a linearized CFG.
2124  }
2125  else {
2126  AC.getCFGBuildOptions()
2127  .setAlwaysAdd(Stmt::BinaryOperatorClass)
2128  .setAlwaysAdd(Stmt::CompoundAssignOperatorClass)
2129  .setAlwaysAdd(Stmt::BlockExprClass)
2130  .setAlwaysAdd(Stmt::CStyleCastExprClass)
2131  .setAlwaysAdd(Stmt::DeclRefExprClass)
2132  .setAlwaysAdd(Stmt::ImplicitCastExprClass)
2133  .setAlwaysAdd(Stmt::UnaryOperatorClass)
2134  .setAlwaysAdd(Stmt::AttributedStmtClass);
2135  }
2136 
2137  // Install the logical handler.
2139  if (LogicalErrorHandler::hasActiveDiagnostics(Diags, D->getBeginLoc())) {
2140  LEH.emplace(S);
2141  AC.getCFGBuildOptions().Observer = &*LEH;
2142  }
2143 
2144  // Emit delayed diagnostics.
2145  if (!fscope->PossiblyUnreachableDiags.empty()) {
2146  bool analyzed = false;
2147 
2148  // Register the expressions with the CFGBuilder.
2149  for (const auto &D : fscope->PossiblyUnreachableDiags) {
2150  for (const Stmt *S : D.Stmts)
2152  }
2153 
2154  if (AC.getCFG()) {
2155  analyzed = true;
2156  for (const auto &D : fscope->PossiblyUnreachableDiags) {
2157  bool AllReachable = true;
2158  for (const Stmt *S : D.Stmts) {
2159  const CFGBlock *block = AC.getBlockForRegisteredExpression(S);
2162  // FIXME: We should be able to assert that block is non-null, but
2163  // the CFG analysis can skip potentially-evaluated expressions in
2164  // edge cases; see test/Sema/vla-2.c.
2165  if (block && cra) {
2166  // Can this block be reached from the entrance?
2167  if (!cra->isReachable(&AC.getCFG()->getEntry(), block)) {
2168  AllReachable = false;
2169  break;
2170  }
2171  }
2172  // If we cannot map to a basic block, assume the statement is
2173  // reachable.
2174  }
2175 
2176  if (AllReachable)
2177  S.Diag(D.Loc, D.PD);
2178  }
2179  }
2180 
2181  if (!analyzed)
2182  flushDiagnostics(S, fscope);
2183  }
2184 
2185  // Warning: check missing 'return'
2186  if (P.enableCheckFallThrough) {
2187  const CheckFallThroughDiagnostics &CD =
2188  (isa<BlockDecl>(D)
2189  ? CheckFallThroughDiagnostics::MakeForBlock()
2190  : (isa<CXXMethodDecl>(D) &&
2191  cast<CXXMethodDecl>(D)->getOverloadedOperator() == OO_Call &&
2192  cast<CXXMethodDecl>(D)->getParent()->isLambda())
2193  ? CheckFallThroughDiagnostics::MakeForLambda()
2194  : (fscope->isCoroutine()
2195  ? CheckFallThroughDiagnostics::MakeForCoroutine(D)
2196  : CheckFallThroughDiagnostics::MakeForFunction(D)));
2197  CheckFallThroughForBody(S, D, Body, BlockType, CD, AC, fscope);
2198  }
2199 
2200  // Warning: check for unreachable code
2201  if (P.enableCheckUnreachable) {
2202  // Only check for unreachable code on non-template instantiations.
2203  // Different template instantiations can effectively change the control-flow
2204  // and it is very difficult to prove that a snippet of code in a template
2205  // is unreachable for all instantiations.
2206  bool isTemplateInstantiation = false;
2207  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
2208  isTemplateInstantiation = Function->isTemplateInstantiation();
2209  if (!isTemplateInstantiation)
2210  CheckUnreachable(S, AC);
2211  }
2212 
2213  // Check for thread safety violations
2214  if (P.enableThreadSafetyAnalysis) {
2215  SourceLocation FL = AC.getDecl()->getLocation();
2216  SourceLocation FEL = AC.getDecl()->getEndLoc();
2217  threadSafety::ThreadSafetyReporter Reporter(S, FL, FEL);
2218  if (!Diags.isIgnored(diag::warn_thread_safety_beta, D->getBeginLoc()))
2219  Reporter.setIssueBetaWarnings(true);
2220  if (!Diags.isIgnored(diag::warn_thread_safety_verbose, D->getBeginLoc()))
2221  Reporter.setVerbose(true);
2222 
2225  Reporter.emitDiagnostics();
2226  }
2227 
2228  // Check for violations of consumed properties.
2229  if (P.enableConsumedAnalysis) {
2230  consumed::ConsumedWarningsHandler WarningHandler(S);
2231  consumed::ConsumedAnalyzer Analyzer(WarningHandler);
2232  Analyzer.run(AC);
2233  }
2234 
2235  if (!Diags.isIgnored(diag::warn_uninit_var, D->getBeginLoc()) ||
2236  !Diags.isIgnored(diag::warn_sometimes_uninit_var, D->getBeginLoc()) ||
2237  !Diags.isIgnored(diag::warn_maybe_uninit_var, D->getBeginLoc()) ||
2238  !Diags.isIgnored(diag::warn_uninit_const_reference, D->getBeginLoc())) {
2239  if (CFG *cfg = AC.getCFG()) {
2240  UninitValsDiagReporter reporter(S);
2242  std::memset(&stats, 0, sizeof(UninitVariablesAnalysisStats));
2243  runUninitializedVariablesAnalysis(*cast<DeclContext>(D), *cfg, AC,
2244  reporter, stats);
2245 
2246  if (S.CollectStats && stats.NumVariablesAnalyzed > 0) {
2247  ++NumUninitAnalysisFunctions;
2248  NumUninitAnalysisVariables += stats.NumVariablesAnalyzed;
2249  NumUninitAnalysisBlockVisits += stats.NumBlockVisits;
2250  MaxUninitAnalysisVariablesPerFunction =
2251  std::max(MaxUninitAnalysisVariablesPerFunction,
2252  stats.NumVariablesAnalyzed);
2253  MaxUninitAnalysisBlockVisitsPerFunction =
2254  std::max(MaxUninitAnalysisBlockVisitsPerFunction,
2255  stats.NumBlockVisits);
2256  }
2257  }
2258  }
2259 
2260  bool FallThroughDiagFull =
2261  !Diags.isIgnored(diag::warn_unannotated_fallthrough, D->getBeginLoc());
2262  bool FallThroughDiagPerFunction = !Diags.isIgnored(
2263  diag::warn_unannotated_fallthrough_per_function, D->getBeginLoc());
2264  if (FallThroughDiagFull || FallThroughDiagPerFunction ||
2265  fscope->HasFallthroughStmt) {
2266  DiagnoseSwitchLabelsFallthrough(S, AC, !FallThroughDiagFull);
2267  }
2268 
2269  if (S.getLangOpts().ObjCWeak &&
2270  !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, D->getBeginLoc()))
2271  diagnoseRepeatedUseOfWeak(S, fscope, D, AC.getParentMap());
2272 
2273 
2274  // Check for infinite self-recursion in functions
2275  if (!Diags.isIgnored(diag::warn_infinite_recursive_function,
2276  D->getBeginLoc())) {
2277  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
2278  checkRecursiveFunction(S, FD, Body, AC);
2279  }
2280  }
2281 
2282  // Check for throw out of non-throwing function.
2283  if (!Diags.isIgnored(diag::warn_throw_in_noexcept_func, D->getBeginLoc()))
2284  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
2285  if (S.getLangOpts().CPlusPlus && isNoexcept(FD))
2286  checkThrowInNonThrowingFunc(S, FD, AC);
2287 
2288  // If none of the previous checks caused a CFG build, trigger one here
2289  // for the logical error handler.
2290  if (LogicalErrorHandler::hasActiveDiagnostics(Diags, D->getBeginLoc())) {
2291  AC.getCFG();
2292  }
2293 
2294  // Collect statistics about the CFG if it was built.
2295  if (S.CollectStats && AC.isCFGBuilt()) {
2296  ++NumFunctionsAnalyzed;
2297  if (CFG *cfg = AC.getCFG()) {
2298  // If we successfully built a CFG for this context, record some more
2299  // detail information about it.
2300  NumCFGBlocks += cfg->getNumBlockIDs();
2301  MaxCFGBlocksPerFunction = std::max(MaxCFGBlocksPerFunction,
2302  cfg->getNumBlockIDs());
2303  } else {
2304  ++NumFunctionsWithBadCFGs;
2305  }
2306  }
2307 }
2308 
2310  llvm::errs() << "\n*** Analysis Based Warnings Stats:\n";
2311 
2312  unsigned NumCFGsBuilt = NumFunctionsAnalyzed - NumFunctionsWithBadCFGs;
2313  unsigned AvgCFGBlocksPerFunction =
2314  !NumCFGsBuilt ? 0 : NumCFGBlocks/NumCFGsBuilt;
2315  llvm::errs() << NumFunctionsAnalyzed << " functions analyzed ("
2316  << NumFunctionsWithBadCFGs << " w/o CFGs).\n"
2317  << " " << NumCFGBlocks << " CFG blocks built.\n"
2318  << " " << AvgCFGBlocksPerFunction
2319  << " average CFG blocks per function.\n"
2320  << " " << MaxCFGBlocksPerFunction
2321  << " max CFG blocks per function.\n";
2322 
2323  unsigned AvgUninitVariablesPerFunction = !NumUninitAnalysisFunctions ? 0
2324  : NumUninitAnalysisVariables/NumUninitAnalysisFunctions;
2325  unsigned AvgUninitBlockVisitsPerFunction = !NumUninitAnalysisFunctions ? 0
2326  : NumUninitAnalysisBlockVisits/NumUninitAnalysisFunctions;
2327  llvm::errs() << NumUninitAnalysisFunctions
2328  << " functions analyzed for uninitialiazed variables\n"
2329  << " " << NumUninitAnalysisVariables << " variables analyzed.\n"
2330  << " " << AvgUninitVariablesPerFunction
2331  << " average variables per function.\n"
2332  << " " << MaxUninitAnalysisVariablesPerFunction
2333  << " max variables per function.\n"
2334  << " " << NumUninitAnalysisBlockVisits << " block visits.\n"
2335  << " " << AvgUninitBlockVisitsPerFunction
2336  << " average block visits per function.\n"
2337  << " " << MaxUninitAnalysisBlockVisitsPerFunction
2338  << " max block visits per function.\n";
2339 }
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:1783
Passing a guarded variable by reference.
Definition: ThreadSafety.h:47
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.
pred_iterator pred_end()
Definition: CFG.h:938
A (possibly-)qualified type.
Definition: Type.h:655
bool isBlockPointerType() const
Definition: Type.h:6658
SourceLocation getExprLoc() const
Definition: Expr.h:3684
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:128
const Expr * getSubExpr() const
Definition: ExprCXX.h:1167
const Stmt * getStmt() const
Definition: CFG.h:138
succ_iterator succ_begin()
Definition: CFG.h:955
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:1010
Stmt - This represents one statement.
Definition: Stmt.h:68
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3547
CFGBlock & getEntry()
Definition: CFG.h:1318
IfStmt - This represents an if/then/else.
Definition: Stmt.h:1866
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:627
llvm::Expected< T > Expected
Defines the SourceManager interface.
static bool DiagnoseUninitializedConstRefUse(Sema &S, const VarDecl *VD, const UninitUse &Use)
Diagnose uninitialized const reference usages.
static void diagnoseRepeatedUseOfWeak(Sema &S, const sema::FunctionScopeInfo *CurFn, const Decl *D, const ParentMap &PM)
unsigned getBlockID() const
Definition: CFG.h:1074
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID)
Emit a diagnostic.
Definition: Sema.h:1517
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:89
Expr * getImplicitObjectArgument() const
Retrieve the implicit object argument for the member call.
Definition: ExprCXX.cpp:628
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: DeclBase.h:422
bool isVirtual() const
Definition: DeclCXX.h:2005
Opcode getOpcode() const
Definition: Expr.h:3688
StringRef P
OverloadedOperatorKind getCXXOverloadedOperator() const
If this name is the name of an overloadable operator in C++ (e.g., operator+), retrieve the kind of o...
Represents an attribute applied to a statement.
Definition: Stmt.h:1808
bool isBeforeInTranslationUnit(SourceLocation LHS, SourceLocation RHS) const
Determines the order of 2 source locations in the translation unit.
const WeakObjectUseMap & getWeakObjectUses() const
Definition: ScopeInfo.h:406
The use is uninitialized whenever a certain branch is taken.
Stmt * getParent(Stmt *) const
Definition: ParentMap.cpp:134
iterator begin()
Definition: CFG.h:875
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:51
SourceLocation getEndLoc() const LLVM_READONLY
Definition: DeclBase.h:426
T castAs() const
Convert to the specified CFGElement type, asserting that this CFGElement is of the desired type...
Definition: CFG.h:98
bool getSuppressSystemWarnings() const
Definition: Diagnostic.h:638
LockKind getLockKindFromAccessKind(AccessKind AK)
Helper function that returns a LockKind required for the given level of access.
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:983
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:36
Retains information about a function, method, or block that is currently being parsed.
Definition: ScopeInfo.h:98
Represents a variable declaration or definition.
Definition: Decl.h:820
PartialDiagnostic PDiag(unsigned DiagID=0)
Build a partial diagnostic.
Definition: SemaInternal.h:24
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:7153
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:139
The use might be uninitialized.
Stmt * getThen()
Definition: Stmt.h:1953
Defines the Objective-C statement AST node classes.
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1147
Defines the clang::Expr interface and subclasses for C++ expressions.
branch_iterator branch_end() const
LabelStmt - Represents a label, which has a substatement.
Definition: Stmt.h:1764
LockKind
This enum distinguishes between different kinds of lock actions.
Definition: ThreadSafety.h:56
bool pred_empty() const
Definition: CFG.h:977
DeclarationName getDeclName() const
Get the actual, stored name of the declaration, which may be a special name.
Definition: Decl.h:272
Kind getKind() const
Get the kind of uninitialized use.
Expr * getFalseExpr() const
Definition: Expr.h:4014
SourceLocation getBegin() const
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:174
LineState State
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Stmt.cpp:275
branch_iterator branch_begin() const
Branches which inevitably result in the variable being used uninitialized.
AnalysisDeclContext contains the context data for the function, method or block under analysis...
threadSafety::BeforeSet * ThreadSafetyDeclCache
Definition: Sema.h:8820
static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC, bool PerFunction)
succ_range succs()
Definition: CFG.h:965
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Decl.h:723
const LangOptions & getLangOpts() const
Definition: Preprocessor.h:915
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:931
TextDiagnosticBuffer::DiagList DiagList
Stmt * getBody(const FunctionDecl *&Definition) const
Retrieve the body (definition) of the function.
Definition: Decl.cpp:2881
__device__ int
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:608
bool AddCXXDefaultInitExprInCtors
Definition: CFG.h:1249
CFGReverseBlockReachabilityAnalysis * getCFGReachablityAnalysis()
CFGCallback * Observer
Definition: CFG.h:1238
child_range children()
Definition: Stmt.cpp:224
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:153
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3644
static StringRef getFallthroughAttrSpelling(Preprocessor &PP, SourceLocation Loc)
SourceLocation getThrowLoc() const
Definition: ExprCXX.h:1170
Expr * IgnoreParenCasts() LLVM_READONLY
Skip past any parentheses and casts which might surround this expression until reaching a fixed point...
Definition: Expr.cpp:2952
static void CheckUnreachable(Sema &S, AnalysisDeclContext &AC)
CheckUnreachable - Check for unreachable code.
__device__ __2f16 b
DeclContext * getLexicalDeclContext()
getLexicalDeclContext - The declaration context where this Decl was lexically declared (LexicalDC)...
Definition: DeclBase.h:843
__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:1822
const LangOptions & getLangOpts() const
Definition: Sema.h:1430
SourceRange getExceptionSpecSourceRange() const
Attempt to compute an informative source range covering the function exception specification, if any.
Definition: Decl.cpp:3441
A class that does preorder or postorder depth-first traversal on the entire Clang AST and visits each...
__device__ __2f16 float bool s
virtual Decl * getCanonicalDecl()
Retrieves the "canonical" declaration of the given declaration.
Definition: DeclBase.h:901
reverse_iterator rend()
Definition: CFG.h:881
static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD)
DiagnosticsEngine & getDiagnostics() const
Definition: Sema.h:1434
Passing a pt-guarded variable by reference.
Definition: ThreadSafety.h:50
bool hasAttr() const
Definition: DeclBase.h:547
ConditionalOperator - The ?: ternary operator.
Definition: Expr.h:3982
Sema - This implements semantic analysis and AST building for C.
Definition: Sema.h:340
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3886
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:93
static StringRef getOpcodeStr(Opcode Op)
getOpcodeStr - Turn an Opcode enum value into the punctuation char it corresponds to...
Definition: Expr.cpp:1936
Represents a single basic block in a source-level CFG.
Definition: CFG.h:576
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:38
Expr * getCond() const
Definition: Expr.h:4005
This represents one expression.
Definition: Expr.h:110
std::string Label
Represents a source-level, intra-procedural CFG that represents the control-flow of a Stmt...
Definition: CFG.h:1225
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:761
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:7218
#define V(N, I)
Definition: ASTContext.h:2899
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5796
Expr * getCallee()
Definition: Expr.h:2883
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:3122
Stores token information for comparing actual tokens with predefined values.
Definition: Preprocessor.h:89
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:142
std::pair< PartialDiagnosticAt, OptionalNotes > DelayedDiag
Definition: Consumed.h:53
const CFGBlock * getBlockForRegisteredExpression(const Stmt *stmt)
bool handlerCanCatch(QualType HandlerType, QualType ExceptionType)
SourceLocation getEnd() const
Making a function call (e.g. fool())
Definition: ThreadSafety.h:44
CXXMethodDecl * getMethodDecl() const
Retrieve the declaration of the called method.
Definition: ExprCXX.cpp:647
Preprocessor & getPreprocessor() const
Definition: Sema.h:1436
Expr * getCond()
Definition: Stmt.h:1941
A use of a variable, which might be uninitialized.
The result type of a method or function.
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:204
reverse_iterator rbegin()
Definition: CFG.h:880
VarDecl * CoroutinePromise
The promise object for this coroutine, if any.
Definition: ScopeInfo.h:196
This file defines AnalysisDeclContext, a class that manages the analysis context data for context sen...
SourceLocation getEndLoc() const LLVM_READONLY
Definition: Stmt.cpp:287
static CharSourceRange getCharRange(SourceRange R)
CharSourceRange RemoveRange
Code that should be replaced to correct the error.
Definition: Diagnostic.h:74
Kind
QualType getCanonicalType() const
Definition: Type.h:6441
Reading or writing a variable (e.g. x in x = 5;)
Definition: ThreadSafety.h:41
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:1437
Encodes a location in the source.
BuildOptions & setAlwaysAdd(Stmt::StmtClass stmtClass, bool val=true)
Definition: CFG.h:1262
static void visitReachableThrows(CFG *BodyCFG, llvm::function_ref< void(const CXXThrowExpr *, CFGBlock &)> Visit)
SourceLocation getOperatorLoc() const
Definition: Expr.h:3685
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Expr.h:5817
static void EmitDiagForCXXThrowInNonThrowingFunc(Sema &S, SourceLocation OpLoc, const FunctionDecl *FD)
Stmt * getLabel()
Definition: CFG.h:1069
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:266
bool isReachable(const CFGBlock *Src, const CFGBlock *Dst)
Returns true if the block &#39;Dst&#39; can be reached from block &#39;Src&#39;.
Represents a call to a member function that may be written either with member call syntax (e...
Definition: ExprCXX.h:182
llvm::iterator_range< capture_init_iterator > capture_inits()
Retrieve the initialization expressions for this lambda&#39;s captures.
Definition: ExprCXX.h:1938
Stmt * getElse()
Definition: Stmt.h:1962
bool PruneTriviallyFalseEdges
Definition: CFG.h:1239
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:1960
Represents a C++ nested name specifier, such as "\::std::vector<int>::".
AccessKind
bool CollectStats
Flag indicating whether or not to collect detailed statistics.
Definition: Sema.h:405
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:742
unsigned getNumBlockIDs() const
Returns the total number of BlockIDs allocated (which start at 0).
Definition: CFG.h:1394
SourceRange getSourceRange() const override LLVM_READONLY
Source range that this declaration covers.
Definition: Decl.cpp:2007
static bool isLogicalOp(Opcode Opc)
Definition: Expr.h:3776
static void emitDiagnostics(BoundNodes &Match, const Decl *D, BugReporter &BR, AnalysisManager &AM, const ObjCAutoreleaseWriteChecker *Checker)
succ_iterator succ_end()
Definition: CFG.h:956
BuildOptions & setAllAlwaysAdd()
Definition: CFG.h:1267
The use is uninitialized the first time it is reached after we reach the variable&#39;s declaration...
Stmt * getSubStmt()
Definition: Stmt.h:1731
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:226
bool getIgnoreAllWarnings() const
Definition: Diagnostic.h:601
static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body, QualType BlockType, 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...
Optional< T > getAs() const
Convert to the specified CFGElement type, returning None if this CFGElement is not of the desired typ...
Definition: CFG.h:109
Expr * getLHS() const
Definition: Expr.h:3693
pred_iterator pred_begin()
Definition: CFG.h:937
SmallVectorImpl< Branch >::const_iterator branch_iterator
Dataflow Directional Tag Classes.
CFG::BuildOptions & getCFGBuildOptions()
bool isValid() const
Return true if this is a valid SourceLocation object.
EvalResult is a struct with detailed info about an evaluated expression.
Definition: Expr.h:606
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:122
const Expr * getInit() const
Definition: Decl.h:1229
static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg)
StmtClass getStmtClass() const
Definition: Stmt.h:1148
Represents a simple identification of a weak object.
Definition: ScopeInfo.h:247
Stmt * getTerminatorStmt()
Definition: CFG.h:1050
A class that handles the analysis of uniqueness violations.
Definition: Consumed.h:240
bool hasObjCLifetime() const
Definition: Type.h:333
ConstEvaluatedExprVisitor - This class visits &#39;const Expr *&#39;s.
static bool isNoexcept(const FunctionDecl *FD)
Expr * IgnoreParenImpCasts() LLVM_READONLY
Skip past any parentheses and implicit casts which might surround this expression until reaching a fi...
Definition: Expr.cpp:2947
bool isMacroID() const
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:2075
The standard open() call: int open(const char *path, int oflag, ...);.
UnreachableKind
Classifications of unreachable code.
Definition: ReachableCode.h:40
const Expr * getUser() const
Get the expression containing the uninitialized use.
The use is always uninitialized.
TypeSourceInfo * getTypeSourceInfo() const
Definition: Decl.h:700
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:96
__DEVICE__ int max(int __a, int __b)
static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope)
bool hasNoReturnElement() const
Definition: CFG.h:1072
SmallVector< PartialDiagnosticAt, 1 > OptionalNotes
Definition: Consumed.h:52
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:218
CFGCallback defines methods that should be called when a logical operator error is found when buildin...
Definition: CFG.h:1207
bool isValid() const
Expr * getTrueExpr() const
Definition: Expr.h:4009
bool LE(InterpState &S, CodePtr OpPC)
Definition: Interp.h:237
void run(AnalysisDeclContext &AC)
Check a function&#39;s CFG for consumed violations.
Definition: Consumed.cpp:1304
Qualifiers getQualifiers() const
Retrieve the set of qualifiers applied to this type.
Definition: Type.h:6429
Represents a top-level expression in a basic block.
Definition: CFG.h:55
static FixItHint CreateReplacement(CharSourceRange RemoveRange, StringRef Code)
Create a code modification hint that replaces the given source range with the given code string...
Definition: Diagnostic.h:133
capture_range captures() const
Retrieve this lambda&#39;s captures.
Definition: ExprCXX.cpp:1186
SourceManager & getSourceManager() const
Definition: Sema.h:1435
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:263
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:2768
void registerForcedBlockExpression(const Stmt *stmt)
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Expr.h:3698
llvm::SmallDenseMap< WeakObjectProfileTy, WeakUseVector, 8, WeakObjectProfileTy::DenseMapInfo > WeakObjectUseMap
Used to collect all uses of weak objects in a function body.
Definition: ScopeInfo.h:356
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1190
bool isIgnored(unsigned DiagID, SourceLocation Loc) const
Determine whether the diagnostic is known to be ignored.
Definition: Diagnostic.h:829
TemplatedKind getTemplatedKind() const
What kind of templated function this is.
Definition: Decl.cpp:3531
SourceManager & SourceMgr
Definition: Sema.h:402
Annotates a diagnostic with some code that should be inserted, removed, or replaced to fix the proble...
Definition: Diagnostic.h:70
Stmt * getSubStmt()
Definition: Stmt.h:1785
QualType getType() const
Definition: Decl.h:630
A trivial tuple used to represent a source range.
ASTContext & Context
Definition: Sema.h:399
FunctionDecl * getCanonicalDecl() override
Retrieves the "canonical" declaration of the given declaration.
Definition: Decl.cpp:3149
This represents a decl that may have a name.
Definition: Decl.h:223
iterator end()
Definition: CFG.h:876
APSInt & getInt()
Definition: APValue.h:380
Decl * getCalleeDecl()
Definition: Expr.h:2895
void IssueWarnings(Policy P, FunctionScopeInfo *fscope, const Decl *D, QualType BlockType)
SourceLocation getBegin() const
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:430
QualType getType() const
Return the type wrapped by this type source info.
Definition: Type.h:6384
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:128
CFGBlock & getExit()
Definition: CFG.h:1320