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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 } // anonymous namespace
164 
165 //===----------------------------------------------------------------------===//
166 // Check for infinite self-recursion in functions
167 //===----------------------------------------------------------------------===//
168 
169 // Returns true if the function is called anywhere within the CFGBlock.
170 // For member functions, the additional condition of being call from the
171 // this pointer is required.
172 static bool hasRecursiveCallInPath(const FunctionDecl *FD, CFGBlock &Block) {
173  // Process all the Stmt's in this block to find any calls to FD.
174  for (const auto &B : Block) {
175  if (B.getKind() != CFGElement::Statement)
176  continue;
177 
178  const CallExpr *CE = dyn_cast<CallExpr>(B.getAs<CFGStmt>()->getStmt());
179  if (!CE || !CE->getCalleeDecl() ||
180  CE->getCalleeDecl()->getCanonicalDecl() != FD)
181  continue;
182 
183  // Skip function calls which are qualified with a templated class.
184  if (const DeclRefExpr *DRE =
185  dyn_cast<DeclRefExpr>(CE->getCallee()->IgnoreParenImpCasts())) {
186  if (NestedNameSpecifier *NNS = DRE->getQualifier()) {
187  if (NNS->getKind() == NestedNameSpecifier::TypeSpec &&
188  isa<TemplateSpecializationType>(NNS->getAsType())) {
189  continue;
190  }
191  }
192  }
193 
194  const CXXMemberCallExpr *MCE = dyn_cast<CXXMemberCallExpr>(CE);
195  if (!MCE || isa<CXXThisExpr>(MCE->getImplicitObjectArgument()) ||
196  !MCE->getMethodDecl()->isVirtual())
197  return true;
198  }
199  return false;
200 }
201 
202 // Returns true if every path from the entry block passes through a call to FD.
203 static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg) {
204  llvm::SmallPtrSet<CFGBlock *, 16> Visited;
206  // Keep track of whether we found at least one recursive path.
207  bool foundRecursion = false;
208 
209  const unsigned ExitID = cfg->getExit().getBlockID();
210 
211  // Seed the work list with the entry block.
212  WorkList.push_back(&cfg->getEntry());
213 
214  while (!WorkList.empty()) {
215  CFGBlock *Block = WorkList.pop_back_val();
216 
217  for (auto I = Block->succ_begin(), E = Block->succ_end(); I != E; ++I) {
218  if (CFGBlock *SuccBlock = *I) {
219  if (!Visited.insert(SuccBlock).second)
220  continue;
221 
222  // Found a path to the exit node without a recursive call.
223  if (ExitID == SuccBlock->getBlockID())
224  return false;
225 
226  // If the successor block contains a recursive call, end analysis there.
227  if (hasRecursiveCallInPath(FD, *SuccBlock)) {
228  foundRecursion = true;
229  continue;
230  }
231 
232  WorkList.push_back(SuccBlock);
233  }
234  }
235  }
236  return foundRecursion;
237 }
238 
239 static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD,
240  const Stmt *Body, AnalysisDeclContext &AC) {
241  FD = FD->getCanonicalDecl();
242 
243  // Only run on non-templated functions and non-templated members of
244  // templated classes.
247  return;
248 
249  CFG *cfg = AC.getCFG();
250  if (!cfg) return;
251 
252  // If the exit block is unreachable, skip processing the function.
253  if (cfg->getExit().pred_empty())
254  return;
255 
256  // Emit diagnostic if a recursive function call is detected for all paths.
257  if (checkForRecursiveFunctionCall(FD, cfg))
258  S.Diag(Body->getBeginLoc(), diag::warn_infinite_recursive_function);
259 }
260 
261 //===----------------------------------------------------------------------===//
262 // Check for throw in a non-throwing function.
263 //===----------------------------------------------------------------------===//
264 
265 /// Determine whether an exception thrown by E, unwinding from ThrowBlock,
266 /// can reach ExitBlock.
267 static bool throwEscapes(Sema &S, const CXXThrowExpr *E, CFGBlock &ThrowBlock,
268  CFG *Body) {
270  llvm::BitVector Queued(Body->getNumBlockIDs());
271 
272  Stack.push_back(&ThrowBlock);
273  Queued[ThrowBlock.getBlockID()] = true;
274 
275  while (!Stack.empty()) {
276  CFGBlock &UnwindBlock = *Stack.back();
277  Stack.pop_back();
278 
279  for (auto &Succ : UnwindBlock.succs()) {
280  if (!Succ.isReachable() || Queued[Succ->getBlockID()])
281  continue;
282 
283  if (Succ->getBlockID() == Body->getExit().getBlockID())
284  return true;
285 
286  if (auto *Catch =
287  dyn_cast_or_null<CXXCatchStmt>(Succ->getLabel())) {
288  QualType Caught = Catch->getCaughtType();
289  if (Caught.isNull() || // catch (...) catches everything
290  !E->getSubExpr() || // throw; is considered cuaght by any handler
291  S.handlerCanCatch(Caught, E->getSubExpr()->getType()))
292  // Exception doesn't escape via this path.
293  break;
294  } else {
295  Stack.push_back(Succ);
296  Queued[Succ->getBlockID()] = true;
297  }
298  }
299  }
300 
301  return false;
302 }
303 
305  CFG *BodyCFG,
306  llvm::function_ref<void(const CXXThrowExpr *, CFGBlock &)> Visit) {
307  llvm::BitVector Reachable(BodyCFG->getNumBlockIDs());
309  for (CFGBlock *B : *BodyCFG) {
310  if (!Reachable[B->getBlockID()])
311  continue;
312  for (CFGElement &E : *B) {
313  Optional<CFGStmt> S = E.getAs<CFGStmt>();
314  if (!S)
315  continue;
316  if (auto *Throw = dyn_cast<CXXThrowExpr>(S->getStmt()))
317  Visit(Throw, *B);
318  }
319  }
320 }
321 
323  const FunctionDecl *FD) {
324  if (!S.getSourceManager().isInSystemHeader(OpLoc) &&
325  FD->getTypeSourceInfo()) {
326  S.Diag(OpLoc, diag::warn_throw_in_noexcept_func) << FD;
327  if (S.getLangOpts().CPlusPlus11 &&
328  (isa<CXXDestructorDecl>(FD) ||
329  FD->getDeclName().getCXXOverloadedOperator() == OO_Delete ||
330  FD->getDeclName().getCXXOverloadedOperator() == OO_Array_Delete)) {
331  if (const auto *Ty = FD->getTypeSourceInfo()->getType()->
332  getAs<FunctionProtoType>())
333  S.Diag(FD->getLocation(), diag::note_throw_in_dtor)
334  << !isa<CXXDestructorDecl>(FD) << !Ty->hasExceptionSpec()
336  } else
337  S.Diag(FD->getLocation(), diag::note_throw_in_function)
339  }
340 }
341 
343  AnalysisDeclContext &AC) {
344  CFG *BodyCFG = AC.getCFG();
345  if (!BodyCFG)
346  return;
347  if (BodyCFG->getExit().pred_empty())
348  return;
349  visitReachableThrows(BodyCFG, [&](const CXXThrowExpr *Throw, CFGBlock &Block) {
350  if (throwEscapes(S, Throw, Block, BodyCFG))
352  });
353 }
354 
355 static bool isNoexcept(const FunctionDecl *FD) {
356  const auto *FPT = FD->getType()->castAs<FunctionProtoType>();
357  if (FPT->isNothrow() || FD->hasAttr<NoThrowAttr>())
358  return true;
359  return false;
360 }
361 
362 //===----------------------------------------------------------------------===//
363 // Check for missing return value.
364 //===----------------------------------------------------------------------===//
365 
372 };
373 
374 /// CheckFallThrough - Check that we don't fall off the end of a
375 /// Statement that should return a value.
376 ///
377 /// \returns AlwaysFallThrough iff we always fall off the end of the statement,
378 /// MaybeFallThrough iff we might or might not fall off the end,
379 /// NeverFallThroughOrReturn iff we never fall off the end of the statement or
380 /// return. We assume NeverFallThrough iff we never fall off the end of the
381 /// statement but we may return. We assume that functions not marked noreturn
382 /// will return.
384  CFG *cfg = AC.getCFG();
385  if (!cfg) return UnknownFallThrough;
386 
387  // The CFG leaves in dead things, and we don't want the dead code paths to
388  // confuse us, so we mark all live things first.
389  llvm::BitVector live(cfg->getNumBlockIDs());
390  unsigned count = reachable_code::ScanReachableFromBlock(&cfg->getEntry(),
391  live);
392 
393  bool AddEHEdges = AC.getAddEHEdges();
394  if (!AddEHEdges && count != cfg->getNumBlockIDs())
395  // When there are things remaining dead, and we didn't add EH edges
396  // from CallExprs to the catch clauses, we have to go back and
397  // mark them as live.
398  for (const auto *B : *cfg) {
399  if (!live[B->getBlockID()]) {
400  if (B->pred_begin() == B->pred_end()) {
401  const Stmt *Term = B->getTerminatorStmt();
402  if (Term && isa<CXXTryStmt>(Term))
403  // When not adding EH edges from calls, catch clauses
404  // can otherwise seem dead. Avoid noting them as dead.
405  count += reachable_code::ScanReachableFromBlock(B, live);
406  continue;
407  }
408  }
409  }
410 
411  // Now we know what is live, we check the live precessors of the exit block
412  // and look for fall through paths, being careful to ignore normal returns,
413  // and exceptional paths.
414  bool HasLiveReturn = false;
415  bool HasFakeEdge = false;
416  bool HasPlainEdge = false;
417  bool HasAbnormalEdge = false;
418 
419  // Ignore default cases that aren't likely to be reachable because all
420  // enums in a switch(X) have explicit case statements.
423 
425  cfg->getExit().filtered_pred_start_end(FO);
426  I.hasMore(); ++I) {
427  const CFGBlock &B = **I;
428  if (!live[B.getBlockID()])
429  continue;
430 
431  // Skip blocks which contain an element marked as no-return. They don't
432  // represent actually viable edges into the exit block, so mark them as
433  // abnormal.
434  if (B.hasNoReturnElement()) {
435  HasAbnormalEdge = true;
436  continue;
437  }
438 
439  // Destructors can appear after the 'return' in the CFG. This is
440  // normal. We need to look pass the destructors for the return
441  // statement (if it exists).
442  CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend();
443 
444  for ( ; ri != re ; ++ri)
445  if (ri->getAs<CFGStmt>())
446  break;
447 
448  // No more CFGElements in the block?
449  if (ri == re) {
450  const Stmt *Term = B.getTerminatorStmt();
451  if (Term && isa<CXXTryStmt>(Term)) {
452  HasAbnormalEdge = true;
453  continue;
454  }
455  // A labeled empty statement, or the entry block...
456  HasPlainEdge = true;
457  continue;
458  }
459 
460  CFGStmt CS = ri->castAs<CFGStmt>();
461  const Stmt *S = CS.getStmt();
462  if (isa<ReturnStmt>(S) || isa<CoreturnStmt>(S)) {
463  HasLiveReturn = true;
464  continue;
465  }
466  if (isa<ObjCAtThrowStmt>(S)) {
467  HasFakeEdge = true;
468  continue;
469  }
470  if (isa<CXXThrowExpr>(S)) {
471  HasFakeEdge = true;
472  continue;
473  }
474  if (isa<MSAsmStmt>(S)) {
475  // TODO: Verify this is correct.
476  HasFakeEdge = true;
477  HasLiveReturn = true;
478  continue;
479  }
480  if (isa<CXXTryStmt>(S)) {
481  HasAbnormalEdge = true;
482  continue;
483  }
484  if (std::find(B.succ_begin(), B.succ_end(), &cfg->getExit())
485  == B.succ_end()) {
486  HasAbnormalEdge = true;
487  continue;
488  }
489 
490  HasPlainEdge = true;
491  }
492  if (!HasPlainEdge) {
493  if (HasLiveReturn)
494  return NeverFallThrough;
496  }
497  if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
498  return MaybeFallThrough;
499  // This says AlwaysFallThrough for calls to functions that are not marked
500  // noreturn, that don't return. If people would like this warning to be more
501  // accurate, such functions should be marked as noreturn.
502  return AlwaysFallThrough;
503 }
504 
505 namespace {
506 
507 struct CheckFallThroughDiagnostics {
508  unsigned diag_MaybeFallThrough_HasNoReturn;
509  unsigned diag_MaybeFallThrough_ReturnsNonVoid;
510  unsigned diag_AlwaysFallThrough_HasNoReturn;
511  unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
512  unsigned diag_NeverFallThroughOrReturn;
513  enum { Function, Block, Lambda, Coroutine } funMode;
514  SourceLocation FuncLoc;
515 
516  static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
517  CheckFallThroughDiagnostics D;
518  D.FuncLoc = Func->getLocation();
519  D.diag_MaybeFallThrough_HasNoReturn =
520  diag::warn_falloff_noreturn_function;
521  D.diag_MaybeFallThrough_ReturnsNonVoid =
522  diag::warn_maybe_falloff_nonvoid_function;
523  D.diag_AlwaysFallThrough_HasNoReturn =
524  diag::warn_falloff_noreturn_function;
525  D.diag_AlwaysFallThrough_ReturnsNonVoid =
526  diag::warn_falloff_nonvoid_function;
527 
528  // Don't suggest that virtual functions be marked "noreturn", since they
529  // might be overridden by non-noreturn functions.
530  bool isVirtualMethod = false;
531  if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Func))
532  isVirtualMethod = Method->isVirtual();
533 
534  // Don't suggest that template instantiations be marked "noreturn"
535  bool isTemplateInstantiation = false;
536  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Func))
537  isTemplateInstantiation = Function->isTemplateInstantiation();
538 
539  if (!isVirtualMethod && !isTemplateInstantiation)
540  D.diag_NeverFallThroughOrReturn =
541  diag::warn_suggest_noreturn_function;
542  else
543  D.diag_NeverFallThroughOrReturn = 0;
544 
545  D.funMode = Function;
546  return D;
547  }
548 
549  static CheckFallThroughDiagnostics MakeForCoroutine(const Decl *Func) {
550  CheckFallThroughDiagnostics D;
551  D.FuncLoc = Func->getLocation();
552  D.diag_MaybeFallThrough_HasNoReturn = 0;
553  D.diag_MaybeFallThrough_ReturnsNonVoid =
554  diag::warn_maybe_falloff_nonvoid_coroutine;
555  D.diag_AlwaysFallThrough_HasNoReturn = 0;
556  D.diag_AlwaysFallThrough_ReturnsNonVoid =
557  diag::warn_falloff_nonvoid_coroutine;
558  D.funMode = Coroutine;
559  return D;
560  }
561 
562  static CheckFallThroughDiagnostics MakeForBlock() {
563  CheckFallThroughDiagnostics D;
564  D.diag_MaybeFallThrough_HasNoReturn =
565  diag::err_noreturn_block_has_return_expr;
566  D.diag_MaybeFallThrough_ReturnsNonVoid =
567  diag::err_maybe_falloff_nonvoid_block;
568  D.diag_AlwaysFallThrough_HasNoReturn =
569  diag::err_noreturn_block_has_return_expr;
570  D.diag_AlwaysFallThrough_ReturnsNonVoid =
571  diag::err_falloff_nonvoid_block;
572  D.diag_NeverFallThroughOrReturn = 0;
573  D.funMode = Block;
574  return D;
575  }
576 
577  static CheckFallThroughDiagnostics MakeForLambda() {
578  CheckFallThroughDiagnostics D;
579  D.diag_MaybeFallThrough_HasNoReturn =
580  diag::err_noreturn_lambda_has_return_expr;
581  D.diag_MaybeFallThrough_ReturnsNonVoid =
582  diag::warn_maybe_falloff_nonvoid_lambda;
583  D.diag_AlwaysFallThrough_HasNoReturn =
584  diag::err_noreturn_lambda_has_return_expr;
585  D.diag_AlwaysFallThrough_ReturnsNonVoid =
586  diag::warn_falloff_nonvoid_lambda;
587  D.diag_NeverFallThroughOrReturn = 0;
588  D.funMode = Lambda;
589  return D;
590  }
591 
592  bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
593  bool HasNoReturn) const {
594  if (funMode == Function) {
595  return (ReturnsVoid ||
596  D.isIgnored(diag::warn_maybe_falloff_nonvoid_function,
597  FuncLoc)) &&
598  (!HasNoReturn ||
599  D.isIgnored(diag::warn_noreturn_function_has_return_expr,
600  FuncLoc)) &&
601  (!ReturnsVoid ||
602  D.isIgnored(diag::warn_suggest_noreturn_block, FuncLoc));
603  }
604  if (funMode == Coroutine) {
605  return (ReturnsVoid ||
606  D.isIgnored(diag::warn_maybe_falloff_nonvoid_function, FuncLoc) ||
607  D.isIgnored(diag::warn_maybe_falloff_nonvoid_coroutine,
608  FuncLoc)) &&
609  (!HasNoReturn);
610  }
611  // For blocks / lambdas.
612  return ReturnsVoid && !HasNoReturn;
613  }
614 };
615 
616 } // anonymous namespace
617 
618 /// CheckFallThroughForBody - Check that we don't fall off the end of a
619 /// function that should return a value. Check that we don't fall off the end
620 /// of a noreturn function. We assume that functions and blocks not marked
621 /// noreturn will return.
622 static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
623  QualType BlockType,
624  const CheckFallThroughDiagnostics &CD,
627 
628  bool ReturnsVoid = false;
629  bool HasNoReturn = false;
630  bool IsCoroutine = FSI->isCoroutine();
631 
632  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
633  if (const auto *CBody = dyn_cast<CoroutineBodyStmt>(Body))
634  ReturnsVoid = CBody->getFallthroughHandler() != nullptr;
635  else
636  ReturnsVoid = FD->getReturnType()->isVoidType();
637  HasNoReturn = FD->isNoReturn();
638  }
639  else if (const auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
640  ReturnsVoid = MD->getReturnType()->isVoidType();
641  HasNoReturn = MD->hasAttr<NoReturnAttr>();
642  }
643  else if (isa<BlockDecl>(D)) {
644  if (const FunctionType *FT =
645  BlockType->getPointeeType()->getAs<FunctionType>()) {
646  if (FT->getReturnType()->isVoidType())
647  ReturnsVoid = true;
648  if (FT->getNoReturnAttr())
649  HasNoReturn = true;
650  }
651  }
652 
653  DiagnosticsEngine &Diags = S.getDiagnostics();
654 
655  // Short circuit for compilation speed.
656  if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn))
657  return;
658  SourceLocation LBrace = Body->getBeginLoc(), RBrace = Body->getEndLoc();
659  auto EmitDiag = [&](SourceLocation Loc, unsigned DiagID) {
660  if (IsCoroutine)
661  S.Diag(Loc, DiagID) << FSI->CoroutinePromise->getType();
662  else
663  S.Diag(Loc, DiagID);
664  };
665 
666  // cpu_dispatch functions permit empty function bodies for ICC compatibility.
668  return;
669 
670  // Either in a function body compound statement, or a function-try-block.
671  switch (CheckFallThrough(AC)) {
672  case UnknownFallThrough:
673  break;
674 
675  case MaybeFallThrough:
676  if (HasNoReturn)
677  EmitDiag(RBrace, CD.diag_MaybeFallThrough_HasNoReturn);
678  else if (!ReturnsVoid)
679  EmitDiag(RBrace, CD.diag_MaybeFallThrough_ReturnsNonVoid);
680  break;
681  case AlwaysFallThrough:
682  if (HasNoReturn)
683  EmitDiag(RBrace, CD.diag_AlwaysFallThrough_HasNoReturn);
684  else if (!ReturnsVoid)
685  EmitDiag(RBrace, CD.diag_AlwaysFallThrough_ReturnsNonVoid);
686  break;
688  if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
689  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
690  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 0 << FD;
691  } else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
692  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn) << 1 << MD;
693  } else {
694  S.Diag(LBrace, CD.diag_NeverFallThroughOrReturn);
695  }
696  }
697  break;
698  case NeverFallThrough:
699  break;
700  }
701 }
702 
703 //===----------------------------------------------------------------------===//
704 // -Wuninitialized
705 //===----------------------------------------------------------------------===//
706 
707 namespace {
708 /// ContainsReference - A visitor class to search for references to
709 /// a particular declaration (the needle) within any evaluated component of an
710 /// expression (recursively).
711 class ContainsReference : public ConstEvaluatedExprVisitor<ContainsReference> {
712  bool FoundReference;
713  const DeclRefExpr *Needle;
714 
715 public:
717 
718  ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
719  : Inherited(Context), FoundReference(false), Needle(Needle) {}
720 
721  void VisitExpr(const Expr *E) {
722  // Stop evaluating if we already have a reference.
723  if (FoundReference)
724  return;
725 
726  Inherited::VisitExpr(E);
727  }
728 
729  void VisitDeclRefExpr(const DeclRefExpr *E) {
730  if (E == Needle)
731  FoundReference = true;
732  else
733  Inherited::VisitDeclRefExpr(E);
734  }
735 
736  bool doesContainReference() const { return FoundReference; }
737 };
738 } // anonymous namespace
739 
740 static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
741  QualType VariableTy = VD->getType().getCanonicalType();
742  if (VariableTy->isBlockPointerType() &&
743  !VD->hasAttr<BlocksAttr>()) {
744  S.Diag(VD->getLocation(), diag::note_block_var_fixit_add_initialization)
745  << VD->getDeclName()
746  << FixItHint::CreateInsertion(VD->getLocation(), "__block ");
747  return true;
748  }
749 
750  // Don't issue a fixit if there is already an initializer.
751  if (VD->getInit())
752  return false;
753 
754  // Don't suggest a fixit inside macros.
755  if (VD->getEndLoc().isMacroID())
756  return false;
757 
759 
760  // Suggest possible initialization (if any).
761  std::string Init = S.getFixItZeroInitializerForType(VariableTy, Loc);
762  if (Init.empty())
763  return false;
764 
765  S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName()
766  << FixItHint::CreateInsertion(Loc, Init);
767  return true;
768 }
769 
770 /// Create a fixit to remove an if-like statement, on the assumption that its
771 /// condition is CondVal.
772 static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then,
773  const Stmt *Else, bool CondVal,
774  FixItHint &Fixit1, FixItHint &Fixit2) {
775  if (CondVal) {
776  // If condition is always true, remove all but the 'then'.
777  Fixit1 = FixItHint::CreateRemoval(
779  if (Else) {
780  SourceLocation ElseKwLoc = S.getLocForEndOfToken(Then->getEndLoc());
781  Fixit2 =
782  FixItHint::CreateRemoval(SourceRange(ElseKwLoc, Else->getEndLoc()));
783  }
784  } else {
785  // If condition is always false, remove all but the 'else'.
786  if (Else)
788  If->getBeginLoc(), Else->getBeginLoc()));
789  else
791  }
792 }
793 
794 /// DiagUninitUse -- Helper function to produce a diagnostic for an
795 /// uninitialized use of a variable.
796 static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
797  bool IsCapturedByBlock) {
798  bool Diagnosed = false;
799 
800  switch (Use.getKind()) {
801  case UninitUse::Always:
802  S.Diag(Use.getUser()->getBeginLoc(), diag::warn_uninit_var)
803  << VD->getDeclName() << IsCapturedByBlock
804  << Use.getUser()->getSourceRange();
805  return;
806 
809  S.Diag(VD->getLocation(), diag::warn_sometimes_uninit_var)
810  << VD->getDeclName() << IsCapturedByBlock
811  << (Use.getKind() == UninitUse::AfterDecl ? 4 : 5)
812  << const_cast<DeclContext*>(VD->getLexicalDeclContext())
813  << VD->getSourceRange();
814  S.Diag(Use.getUser()->getBeginLoc(), diag::note_uninit_var_use)
815  << IsCapturedByBlock << Use.getUser()->getSourceRange();
816  return;
817 
818  case UninitUse::Maybe:
820  // Carry on to report sometimes-uninitialized branches, if possible,
821  // or a 'may be used uninitialized' diagnostic otherwise.
822  break;
823  }
824 
825  // Diagnose each branch which leads to a sometimes-uninitialized use.
826  for (UninitUse::branch_iterator I = Use.branch_begin(), E = Use.branch_end();
827  I != E; ++I) {
828  assert(Use.getKind() == UninitUse::Sometimes);
829 
830  const Expr *User = Use.getUser();
831  const Stmt *Term = I->Terminator;
832 
833  // Information used when building the diagnostic.
834  unsigned DiagKind;
835  StringRef Str;
836  SourceRange Range;
837 
838  // FixIts to suppress the diagnostic by removing the dead condition.
839  // For all binary terminators, branch 0 is taken if the condition is true,
840  // and branch 1 is taken if the condition is false.
841  int RemoveDiagKind = -1;
842  const char *FixitStr =
843  S.getLangOpts().CPlusPlus ? (I->Output ? "true" : "false")
844  : (I->Output ? "1" : "0");
845  FixItHint Fixit1, Fixit2;
846 
847  switch (Term ? Term->getStmtClass() : Stmt::DeclStmtClass) {
848  default:
849  // Don't know how to report this. Just fall back to 'may be used
850  // uninitialized'. FIXME: Can this happen?
851  continue;
852 
853  // "condition is true / condition is false".
854  case Stmt::IfStmtClass: {
855  const IfStmt *IS = cast<IfStmt>(Term);
856  DiagKind = 0;
857  Str = "if";
858  Range = IS->getCond()->getSourceRange();
859  RemoveDiagKind = 0;
860  CreateIfFixit(S, IS, IS->getThen(), IS->getElse(),
861  I->Output, Fixit1, Fixit2);
862  break;
863  }
864  case Stmt::ConditionalOperatorClass: {
865  const ConditionalOperator *CO = cast<ConditionalOperator>(Term);
866  DiagKind = 0;
867  Str = "?:";
868  Range = CO->getCond()->getSourceRange();
869  RemoveDiagKind = 0;
870  CreateIfFixit(S, CO, CO->getTrueExpr(), CO->getFalseExpr(),
871  I->Output, Fixit1, Fixit2);
872  break;
873  }
874  case Stmt::BinaryOperatorClass: {
875  const BinaryOperator *BO = cast<BinaryOperator>(Term);
876  if (!BO->isLogicalOp())
877  continue;
878  DiagKind = 0;
879  Str = BO->getOpcodeStr();
880  Range = BO->getLHS()->getSourceRange();
881  RemoveDiagKind = 0;
882  if ((BO->getOpcode() == BO_LAnd && I->Output) ||
883  (BO->getOpcode() == BO_LOr && !I->Output))
884  // true && y -> y, false || y -> y.
885  Fixit1 = FixItHint::CreateRemoval(
886  SourceRange(BO->getBeginLoc(), BO->getOperatorLoc()));
887  else
888  // false && y -> false, true || y -> true.
889  Fixit1 = FixItHint::CreateReplacement(BO->getSourceRange(), FixitStr);
890  break;
891  }
892 
893  // "loop is entered / loop is exited".
894  case Stmt::WhileStmtClass:
895  DiagKind = 1;
896  Str = "while";
897  Range = cast<WhileStmt>(Term)->getCond()->getSourceRange();
898  RemoveDiagKind = 1;
899  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
900  break;
901  case Stmt::ForStmtClass:
902  DiagKind = 1;
903  Str = "for";
904  Range = cast<ForStmt>(Term)->getCond()->getSourceRange();
905  RemoveDiagKind = 1;
906  if (I->Output)
907  Fixit1 = FixItHint::CreateRemoval(Range);
908  else
909  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
910  break;
911  case Stmt::CXXForRangeStmtClass:
912  if (I->Output == 1) {
913  // The use occurs if a range-based for loop's body never executes.
914  // That may be impossible, and there's no syntactic fix for this,
915  // so treat it as a 'may be uninitialized' case.
916  continue;
917  }
918  DiagKind = 1;
919  Str = "for";
920  Range = cast<CXXForRangeStmt>(Term)->getRangeInit()->getSourceRange();
921  break;
922 
923  // "condition is true / loop is exited".
924  case Stmt::DoStmtClass:
925  DiagKind = 2;
926  Str = "do";
927  Range = cast<DoStmt>(Term)->getCond()->getSourceRange();
928  RemoveDiagKind = 1;
929  Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
930  break;
931 
932  // "switch case is taken".
933  case Stmt::CaseStmtClass:
934  DiagKind = 3;
935  Str = "case";
936  Range = cast<CaseStmt>(Term)->getLHS()->getSourceRange();
937  break;
938  case Stmt::DefaultStmtClass:
939  DiagKind = 3;
940  Str = "default";
941  Range = cast<DefaultStmt>(Term)->getDefaultLoc();
942  break;
943  }
944 
945  S.Diag(Range.getBegin(), diag::warn_sometimes_uninit_var)
946  << VD->getDeclName() << IsCapturedByBlock << DiagKind
947  << Str << I->Output << Range;
948  S.Diag(User->getBeginLoc(), diag::note_uninit_var_use)
949  << IsCapturedByBlock << User->getSourceRange();
950  if (RemoveDiagKind != -1)
951  S.Diag(Fixit1.RemoveRange.getBegin(), diag::note_uninit_fixit_remove_cond)
952  << RemoveDiagKind << Str << I->Output << Fixit1 << Fixit2;
953 
954  Diagnosed = true;
955  }
956 
957  if (!Diagnosed)
958  S.Diag(Use.getUser()->getBeginLoc(), diag::warn_maybe_uninit_var)
959  << VD->getDeclName() << IsCapturedByBlock
960  << Use.getUser()->getSourceRange();
961 }
962 
963 /// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
964 /// uninitialized variable. This manages the different forms of diagnostic
965 /// emitted for particular types of uses. Returns true if the use was diagnosed
966 /// as a warning. If a particular use is one we omit warnings for, returns
967 /// false.
968 static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
969  const UninitUse &Use,
970  bool alwaysReportSelfInit = false) {
971  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Use.getUser())) {
972  // Inspect the initializer of the variable declaration which is
973  // being referenced prior to its initialization. We emit
974  // specialized diagnostics for self-initialization, and we
975  // specifically avoid warning about self references which take the
976  // form of:
977  //
978  // int x = x;
979  //
980  // This is used to indicate to GCC that 'x' is intentionally left
981  // uninitialized. Proven code paths which access 'x' in
982  // an uninitialized state after this will still warn.
983  if (const Expr *Initializer = VD->getInit()) {
984  if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
985  return false;
986 
987  ContainsReference CR(S.Context, DRE);
988  CR.Visit(Initializer);
989  if (CR.doesContainReference()) {
990  S.Diag(DRE->getBeginLoc(), diag::warn_uninit_self_reference_in_init)
991  << VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
992  return true;
993  }
994  }
995 
996  DiagUninitUse(S, VD, Use, false);
997  } else {
998  const BlockExpr *BE = cast<BlockExpr>(Use.getUser());
999  if (VD->getType()->isBlockPointerType() && !VD->hasAttr<BlocksAttr>())
1000  S.Diag(BE->getBeginLoc(),
1001  diag::warn_uninit_byref_blockvar_captured_by_block)
1002  << VD->getDeclName()
1003  << VD->getType().getQualifiers().hasObjCLifetime();
1004  else
1005  DiagUninitUse(S, VD, Use, true);
1006  }
1007 
1008  // Report where the variable was declared when the use wasn't within
1009  // the initializer of that declaration & we didn't already suggest
1010  // an initialization fixit.
1011  if (!SuggestInitializationFixit(S, VD))
1012  S.Diag(VD->getBeginLoc(), diag::note_var_declared_here)
1013  << VD->getDeclName();
1014 
1015  return true;
1016 }
1017 
1018 namespace {
1019  class FallthroughMapper : public RecursiveASTVisitor<FallthroughMapper> {
1020  public:
1021  FallthroughMapper(Sema &S)
1022  : FoundSwitchStatements(false),
1023  S(S) {
1024  }
1025 
1026  bool foundSwitchStatements() const { return FoundSwitchStatements; }
1027 
1028  void markFallthroughVisited(const AttributedStmt *Stmt) {
1029  bool Found = FallthroughStmts.erase(Stmt);
1030  assert(Found);
1031  (void)Found;
1032  }
1033 
1034  typedef llvm::SmallPtrSet<const AttributedStmt*, 8> AttrStmts;
1035 
1036  const AttrStmts &getFallthroughStmts() const {
1037  return FallthroughStmts;
1038  }
1039 
1040  void fillReachableBlocks(CFG *Cfg) {
1041  assert(ReachableBlocks.empty() && "ReachableBlocks already filled");
1042  std::deque<const CFGBlock *> BlockQueue;
1043 
1044  ReachableBlocks.insert(&Cfg->getEntry());
1045  BlockQueue.push_back(&Cfg->getEntry());
1046  // Mark all case blocks reachable to avoid problems with switching on
1047  // constants, covered enums, etc.
1048  // These blocks can contain fall-through annotations, and we don't want to
1049  // issue a warn_fallthrough_attr_unreachable for them.
1050  for (const auto *B : *Cfg) {
1051  const Stmt *L = B->getLabel();
1052  if (L && isa<SwitchCase>(L) && ReachableBlocks.insert(B).second)
1053  BlockQueue.push_back(B);
1054  }
1055 
1056  while (!BlockQueue.empty()) {
1057  const CFGBlock *P = BlockQueue.front();
1058  BlockQueue.pop_front();
1060  E = P->succ_end();
1061  I != E; ++I) {
1062  if (*I && ReachableBlocks.insert(*I).second)
1063  BlockQueue.push_back(*I);
1064  }
1065  }
1066  }
1067 
1068  bool checkFallThroughIntoBlock(const CFGBlock &B, int &AnnotatedCnt,
1069  bool IsTemplateInstantiation) {
1070  assert(!ReachableBlocks.empty() && "ReachableBlocks empty");
1071 
1072  int UnannotatedCnt = 0;
1073  AnnotatedCnt = 0;
1074 
1075  std::deque<const CFGBlock*> BlockQueue(B.pred_begin(), B.pred_end());
1076  while (!BlockQueue.empty()) {
1077  const CFGBlock *P = BlockQueue.front();
1078  BlockQueue.pop_front();
1079  if (!P) continue;
1080 
1081  const Stmt *Term = P->getTerminatorStmt();
1082  if (Term && isa<SwitchStmt>(Term))
1083  continue; // Switch statement, good.
1084 
1085  const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(P->getLabel());
1086  if (SW && SW->getSubStmt() == B.getLabel() && P->begin() == P->end())
1087  continue; // Previous case label has no statements, good.
1088 
1089  const LabelStmt *L = dyn_cast_or_null<LabelStmt>(P->getLabel());
1090  if (L && L->getSubStmt() == B.getLabel() && P->begin() == P->end())
1091  continue; // Case label is preceded with a normal label, good.
1092 
1093  if (!ReachableBlocks.count(P)) {
1094  for (CFGBlock::const_reverse_iterator ElemIt = P->rbegin(),
1095  ElemEnd = P->rend();
1096  ElemIt != ElemEnd; ++ElemIt) {
1097  if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>()) {
1098  if (const AttributedStmt *AS = asFallThroughAttr(CS->getStmt())) {
1099  // Don't issue a warning for an unreachable fallthrough
1100  // attribute in template instantiations as it may not be
1101  // unreachable in all instantiations of the template.
1102  if (!IsTemplateInstantiation)
1103  S.Diag(AS->getBeginLoc(),
1104  diag::warn_fallthrough_attr_unreachable);
1105  markFallthroughVisited(AS);
1106  ++AnnotatedCnt;
1107  break;
1108  }
1109  // Don't care about other unreachable statements.
1110  }
1111  }
1112  // If there are no unreachable statements, this may be a special
1113  // case in CFG:
1114  // case X: {
1115  // A a; // A has a destructor.
1116  // break;
1117  // }
1118  // // <<<< This place is represented by a 'hanging' CFG block.
1119  // case Y:
1120  continue;
1121  }
1122 
1123  const Stmt *LastStmt = getLastStmt(*P);
1124  if (const AttributedStmt *AS = asFallThroughAttr(LastStmt)) {
1125  markFallthroughVisited(AS);
1126  ++AnnotatedCnt;
1127  continue; // Fallthrough annotation, good.
1128  }
1129 
1130  if (!LastStmt) { // This block contains no executable statements.
1131  // Traverse its predecessors.
1132  std::copy(P->pred_begin(), P->pred_end(),
1133  std::back_inserter(BlockQueue));
1134  continue;
1135  }
1136 
1137  ++UnannotatedCnt;
1138  }
1139  return !!UnannotatedCnt;
1140  }
1141 
1142  // RecursiveASTVisitor setup.
1143  bool shouldWalkTypesOfTypeLocs() const { return false; }
1144 
1145  bool VisitAttributedStmt(AttributedStmt *S) {
1146  if (asFallThroughAttr(S))
1147  FallthroughStmts.insert(S);
1148  return true;
1149  }
1150 
1151  bool VisitSwitchStmt(SwitchStmt *S) {
1152  FoundSwitchStatements = true;
1153  return true;
1154  }
1155 
1156  // We don't want to traverse local type declarations. We analyze their
1157  // methods separately.
1158  bool TraverseDecl(Decl *D) { return true; }
1159 
1160  // We analyze lambda bodies separately. Skip them here.
1161  bool TraverseLambdaExpr(LambdaExpr *LE) {
1162  // Traverse the captures, but not the body.
1163  for (const auto &C : zip(LE->captures(), LE->capture_inits()))
1164  TraverseLambdaCapture(LE, &std::get<0>(C), std::get<1>(C));
1165  return true;
1166  }
1167 
1168  private:
1169 
1170  static const AttributedStmt *asFallThroughAttr(const Stmt *S) {
1171  if (const AttributedStmt *AS = dyn_cast_or_null<AttributedStmt>(S)) {
1172  if (hasSpecificAttr<FallThroughAttr>(AS->getAttrs()))
1173  return AS;
1174  }
1175  return nullptr;
1176  }
1177 
1178  static const Stmt *getLastStmt(const CFGBlock &B) {
1179  if (const Stmt *Term = B.getTerminatorStmt())
1180  return Term;
1181  for (CFGBlock::const_reverse_iterator ElemIt = B.rbegin(),
1182  ElemEnd = B.rend();
1183  ElemIt != ElemEnd; ++ElemIt) {
1184  if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>())
1185  return CS->getStmt();
1186  }
1187  // Workaround to detect a statement thrown out by CFGBuilder:
1188  // case X: {} case Y:
1189  // case X: ; case Y:
1190  if (const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(B.getLabel()))
1191  if (!isa<SwitchCase>(SW->getSubStmt()))
1192  return SW->getSubStmt();
1193 
1194  return nullptr;
1195  }
1196 
1197  bool FoundSwitchStatements;
1198  AttrStmts FallthroughStmts;
1199  Sema &S;
1200  llvm::SmallPtrSet<const CFGBlock *, 16> ReachableBlocks;
1201  };
1202 } // anonymous namespace
1203 
1205  SourceLocation Loc) {
1206  TokenValue FallthroughTokens[] = {
1207  tok::l_square, tok::l_square,
1208  PP.getIdentifierInfo("fallthrough"),
1209  tok::r_square, tok::r_square
1210  };
1211 
1212  TokenValue ClangFallthroughTokens[] = {
1213  tok::l_square, tok::l_square, PP.getIdentifierInfo("clang"),
1214  tok::coloncolon, PP.getIdentifierInfo("fallthrough"),
1215  tok::r_square, tok::r_square
1216  };
1217 
1218  bool PreferClangAttr = !PP.getLangOpts().CPlusPlus17 && !PP.getLangOpts().C2x;
1219 
1220  StringRef MacroName;
1221  if (PreferClangAttr)
1222  MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
1223  if (MacroName.empty())
1224  MacroName = PP.getLastMacroWithSpelling(Loc, FallthroughTokens);
1225  if (MacroName.empty() && !PreferClangAttr)
1226  MacroName = PP.getLastMacroWithSpelling(Loc, ClangFallthroughTokens);
1227  if (MacroName.empty()) {
1228  if (!PreferClangAttr)
1229  MacroName = "[[fallthrough]]";
1230  else if (PP.getLangOpts().CPlusPlus)
1231  MacroName = "[[clang::fallthrough]]";
1232  else
1233  MacroName = "__attribute__((fallthrough))";
1234  }
1235  return MacroName;
1236 }
1237 
1239  bool PerFunction) {
1240  FallthroughMapper FM(S);
1241  FM.TraverseStmt(AC.getBody());
1242 
1243  if (!FM.foundSwitchStatements())
1244  return;
1245 
1246  if (PerFunction && FM.getFallthroughStmts().empty())
1247  return;
1248 
1249  CFG *Cfg = AC.getCFG();
1250 
1251  if (!Cfg)
1252  return;
1253 
1254  FM.fillReachableBlocks(Cfg);
1255 
1256  for (const CFGBlock *B : llvm::reverse(*Cfg)) {
1257  const Stmt *Label = B->getLabel();
1258 
1259  if (!Label || !isa<SwitchCase>(Label))
1260  continue;
1261 
1262  int AnnotatedCnt;
1263 
1264  bool IsTemplateInstantiation = false;
1265  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(AC.getDecl()))
1266  IsTemplateInstantiation = Function->isTemplateInstantiation();
1267  if (!FM.checkFallThroughIntoBlock(*B, AnnotatedCnt,
1268  IsTemplateInstantiation))
1269  continue;
1270 
1271  S.Diag(Label->getBeginLoc(),
1272  PerFunction ? diag::warn_unannotated_fallthrough_per_function
1273  : diag::warn_unannotated_fallthrough);
1274 
1275  if (!AnnotatedCnt) {
1276  SourceLocation L = Label->getBeginLoc();
1277  if (L.isMacroID())
1278  continue;
1279 
1280  const Stmt *Term = B->getTerminatorStmt();
1281  // Skip empty cases.
1282  while (B->empty() && !Term && B->succ_size() == 1) {
1283  B = *B->succ_begin();
1284  Term = B->getTerminatorStmt();
1285  }
1286  if (!(B->empty() && Term && isa<BreakStmt>(Term))) {
1287  Preprocessor &PP = S.getPreprocessor();
1288  StringRef AnnotationSpelling = getFallthroughAttrSpelling(PP, L);
1289  SmallString<64> TextToInsert(AnnotationSpelling);
1290  TextToInsert += "; ";
1291  S.Diag(L, diag::note_insert_fallthrough_fixit)
1292  << AnnotationSpelling
1293  << FixItHint::CreateInsertion(L, TextToInsert);
1294  }
1295  S.Diag(L, diag::note_insert_break_fixit)
1296  << FixItHint::CreateInsertion(L, "break; ");
1297  }
1298  }
1299 
1300  for (const auto *F : FM.getFallthroughStmts())
1301  S.Diag(F->getBeginLoc(), diag::err_fallthrough_attr_invalid_placement);
1302 }
1303 
1304 static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM,
1305  const Stmt *S) {
1306  assert(S);
1307 
1308  do {
1309  switch (S->getStmtClass()) {
1310  case Stmt::ForStmtClass:
1311  case Stmt::WhileStmtClass:
1312  case Stmt::CXXForRangeStmtClass:
1313  case Stmt::ObjCForCollectionStmtClass:
1314  return true;
1315  case Stmt::DoStmtClass: {
1317  if (!cast<DoStmt>(S)->getCond()->EvaluateAsInt(Result, Ctx))
1318  return true;
1319  return Result.Val.getInt().getBoolValue();
1320  }
1321  default:
1322  break;
1323  }
1324  } while ((S = PM.getParent(S)));
1325 
1326  return false;
1327 }
1328 
1330  const sema::FunctionScopeInfo *CurFn,
1331  const Decl *D,
1332  const ParentMap &PM) {
1333  typedef sema::FunctionScopeInfo::WeakObjectProfileTy WeakObjectProfileTy;
1334  typedef sema::FunctionScopeInfo::WeakObjectUseMap WeakObjectUseMap;
1335  typedef sema::FunctionScopeInfo::WeakUseVector WeakUseVector;
1336  typedef std::pair<const Stmt *, WeakObjectUseMap::const_iterator>
1337  StmtUsesPair;
1338 
1339  ASTContext &Ctx = S.getASTContext();
1340 
1341  const WeakObjectUseMap &WeakMap = CurFn->getWeakObjectUses();
1342 
1343  // Extract all weak objects that are referenced more than once.
1344  SmallVector<StmtUsesPair, 8> UsesByStmt;
1345  for (WeakObjectUseMap::const_iterator I = WeakMap.begin(), E = WeakMap.end();
1346  I != E; ++I) {
1347  const WeakUseVector &Uses = I->second;
1348 
1349  // Find the first read of the weak object.
1350  WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
1351  for ( ; UI != UE; ++UI) {
1352  if (UI->isUnsafe())
1353  break;
1354  }
1355 
1356  // If there were only writes to this object, don't warn.
1357  if (UI == UE)
1358  continue;
1359 
1360  // If there was only one read, followed by any number of writes, and the
1361  // read is not within a loop, don't warn. Additionally, don't warn in a
1362  // loop if the base object is a local variable -- local variables are often
1363  // changed in loops.
1364  if (UI == Uses.begin()) {
1365  WeakUseVector::const_iterator UI2 = UI;
1366  for (++UI2; UI2 != UE; ++UI2)
1367  if (UI2->isUnsafe())
1368  break;
1369 
1370  if (UI2 == UE) {
1371  if (!isInLoop(Ctx, PM, UI->getUseExpr()))
1372  continue;
1373 
1374  const WeakObjectProfileTy &Profile = I->first;
1375  if (!Profile.isExactProfile())
1376  continue;
1377 
1378  const NamedDecl *Base = Profile.getBase();
1379  if (!Base)
1380  Base = Profile.getProperty();
1381  assert(Base && "A profile always has a base or property.");
1382 
1383  if (const VarDecl *BaseVar = dyn_cast<VarDecl>(Base))
1384  if (BaseVar->hasLocalStorage() && !isa<ParmVarDecl>(Base))
1385  continue;
1386  }
1387  }
1388 
1389  UsesByStmt.push_back(StmtUsesPair(UI->getUseExpr(), I));
1390  }
1391 
1392  if (UsesByStmt.empty())
1393  return;
1394 
1395  // Sort by first use so that we emit the warnings in a deterministic order.
1397  llvm::sort(UsesByStmt,
1398  [&SM](const StmtUsesPair &LHS, const StmtUsesPair &RHS) {
1399  return SM.isBeforeInTranslationUnit(LHS.first->getBeginLoc(),
1400  RHS.first->getBeginLoc());
1401  });
1402 
1403  // Classify the current code body for better warning text.
1404  // This enum should stay in sync with the cases in
1405  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1406  // FIXME: Should we use a common classification enum and the same set of
1407  // possibilities all throughout Sema?
1408  enum {
1409  Function,
1410  Method,
1411  Block,
1412  Lambda
1413  } FunctionKind;
1414 
1415  if (isa<sema::BlockScopeInfo>(CurFn))
1416  FunctionKind = Block;
1417  else if (isa<sema::LambdaScopeInfo>(CurFn))
1418  FunctionKind = Lambda;
1419  else if (isa<ObjCMethodDecl>(D))
1420  FunctionKind = Method;
1421  else
1422  FunctionKind = Function;
1423 
1424  // Iterate through the sorted problems and emit warnings for each.
1425  for (const auto &P : UsesByStmt) {
1426  const Stmt *FirstRead = P.first;
1427  const WeakObjectProfileTy &Key = P.second->first;
1428  const WeakUseVector &Uses = P.second->second;
1429 
1430  // For complicated expressions like 'a.b.c' and 'x.b.c', WeakObjectProfileTy
1431  // may not contain enough information to determine that these are different
1432  // properties. We can only be 100% sure of a repeated use in certain cases,
1433  // and we adjust the diagnostic kind accordingly so that the less certain
1434  // case can be turned off if it is too noisy.
1435  unsigned DiagKind;
1436  if (Key.isExactProfile())
1437  DiagKind = diag::warn_arc_repeated_use_of_weak;
1438  else
1439  DiagKind = diag::warn_arc_possible_repeated_use_of_weak;
1440 
1441  // Classify the weak object being accessed for better warning text.
1442  // This enum should stay in sync with the cases in
1443  // warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
1444  enum {
1445  Variable,
1446  Property,
1447  ImplicitProperty,
1448  Ivar
1449  } ObjectKind;
1450 
1451  const NamedDecl *KeyProp = Key.getProperty();
1452  if (isa<VarDecl>(KeyProp))
1453  ObjectKind = Variable;
1454  else if (isa<ObjCPropertyDecl>(KeyProp))
1455  ObjectKind = Property;
1456  else if (isa<ObjCMethodDecl>(KeyProp))
1457  ObjectKind = ImplicitProperty;
1458  else if (isa<ObjCIvarDecl>(KeyProp))
1459  ObjectKind = Ivar;
1460  else
1461  llvm_unreachable("Unexpected weak object kind!");
1462 
1463  // Do not warn about IBOutlet weak property receivers being set to null
1464  // since they are typically only used from the main thread.
1465  if (const ObjCPropertyDecl *Prop = dyn_cast<ObjCPropertyDecl>(KeyProp))
1466  if (Prop->hasAttr<IBOutletAttr>())
1467  continue;
1468 
1469  // Show the first time the object was read.
1470  S.Diag(FirstRead->getBeginLoc(), DiagKind)
1471  << int(ObjectKind) << KeyProp << int(FunctionKind)
1472  << FirstRead->getSourceRange();
1473 
1474  // Print all the other accesses as notes.
1475  for (const auto &Use : Uses) {
1476  if (Use.getUseExpr() == FirstRead)
1477  continue;
1478  S.Diag(Use.getUseExpr()->getBeginLoc(),
1479  diag::note_arc_weak_also_accessed_here)
1480  << Use.getUseExpr()->getSourceRange();
1481  }
1482  }
1483 }
1484 
1485 namespace {
1486 class UninitValsDiagReporter : public UninitVariablesHandler {
1487  Sema &S;
1488  typedef SmallVector<UninitUse, 2> UsesVec;
1489  typedef llvm::PointerIntPair<UsesVec *, 1, bool> MappedType;
1490  // Prefer using MapVector to DenseMap, so that iteration order will be
1491  // the same as insertion order. This is needed to obtain a deterministic
1492  // order of diagnostics when calling flushDiagnostics().
1493  typedef llvm::MapVector<const VarDecl *, MappedType> UsesMap;
1494  UsesMap uses;
1495 
1496 public:
1497  UninitValsDiagReporter(Sema &S) : S(S) {}
1498  ~UninitValsDiagReporter() override { flushDiagnostics(); }
1499 
1500  MappedType &getUses(const VarDecl *vd) {
1501  MappedType &V = uses[vd];
1502  if (!V.getPointer())
1503  V.setPointer(new UsesVec());
1504  return V;
1505  }
1506 
1507  void handleUseOfUninitVariable(const VarDecl *vd,
1508  const UninitUse &use) override {
1509  getUses(vd).getPointer()->push_back(use);
1510  }
1511 
1512  void handleSelfInit(const VarDecl *vd) override {
1513  getUses(vd).setInt(true);
1514  }
1515 
1516  void flushDiagnostics() {
1517  for (const auto &P : uses) {
1518  const VarDecl *vd = P.first;
1519  const MappedType &V = P.second;
1520 
1521  UsesVec *vec = V.getPointer();
1522  bool hasSelfInit = V.getInt();
1523 
1524  // Specially handle the case where we have uses of an uninitialized
1525  // variable, but the root cause is an idiomatic self-init. We want
1526  // to report the diagnostic at the self-init since that is the root cause.
1527  if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
1530  /* isAlwaysUninit */ true),
1531  /* alwaysReportSelfInit */ true);
1532  else {
1533  // Sort the uses by their SourceLocations. While not strictly
1534  // guaranteed to produce them in line/column order, this will provide
1535  // a stable ordering.
1536  llvm::sort(vec->begin(), vec->end(),
1537  [](const UninitUse &a, const UninitUse &b) {
1538  // Prefer a more confident report over a less confident one.
1539  if (a.getKind() != b.getKind())
1540  return a.getKind() > b.getKind();
1541  return a.getUser()->getBeginLoc() < b.getUser()->getBeginLoc();
1542  });
1543 
1544  for (const auto &U : *vec) {
1545  // If we have self-init, downgrade all uses to 'may be uninitialized'.
1546  UninitUse Use = hasSelfInit ? UninitUse(U.getUser(), false) : U;
1547 
1548  if (DiagnoseUninitializedUse(S, vd, Use))
1549  // Skip further diagnostics for this variable. We try to warn only
1550  // on the first point at which a variable is used uninitialized.
1551  break;
1552  }
1553  }
1554 
1555  // Release the uses vector.
1556  delete vec;
1557  }
1558 
1559  uses.clear();
1560  }
1561 
1562 private:
1563  static bool hasAlwaysUninitializedUse(const UsesVec* vec) {
1564  return std::any_of(vec->begin(), vec->end(), [](const UninitUse &U) {
1565  return U.getKind() == UninitUse::Always ||
1566  U.getKind() == UninitUse::AfterCall ||
1567  U.getKind() == UninitUse::AfterDecl;
1568  });
1569  }
1570 };
1571 } // anonymous namespace
1572 
1573 namespace clang {
1574 namespace {
1576 typedef std::pair<PartialDiagnosticAt, OptionalNotes> DelayedDiag;
1577 typedef std::list<DelayedDiag> DiagList;
1578 
1579 struct SortDiagBySourceLocation {
1581  SortDiagBySourceLocation(SourceManager &SM) : SM(SM) {}
1582 
1583  bool operator()(const DelayedDiag &left, const DelayedDiag &right) {
1584  // Although this call will be slow, this is only called when outputting
1585  // multiple warnings.
1586  return SM.isBeforeInTranslationUnit(left.first.first, right.first.first);
1587  }
1588 };
1589 } // anonymous namespace
1590 } // namespace clang
1591 
1592 //===----------------------------------------------------------------------===//
1593 // -Wthread-safety
1594 //===----------------------------------------------------------------------===//
1595 namespace clang {
1596 namespace threadSafety {
1597 namespace {
1598 class ThreadSafetyReporter : public clang::threadSafety::ThreadSafetyHandler {
1599  Sema &S;
1600  DiagList Warnings;
1601  SourceLocation FunLocation, FunEndLocation;
1602 
1603  const FunctionDecl *CurrentFunction;
1604  bool Verbose;
1605 
1606  OptionalNotes getNotes() const {
1607  if (Verbose && CurrentFunction) {
1608  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
1609  S.PDiag(diag::note_thread_warning_in_fun)
1610  << CurrentFunction);
1611  return OptionalNotes(1, FNote);
1612  }
1613  return OptionalNotes();
1614  }
1615 
1616  OptionalNotes getNotes(const PartialDiagnosticAt &Note) const {
1617  OptionalNotes ONS(1, Note);
1618  if (Verbose && CurrentFunction) {
1619  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
1620  S.PDiag(diag::note_thread_warning_in_fun)
1621  << CurrentFunction);
1622  ONS.push_back(std::move(FNote));
1623  }
1624  return ONS;
1625  }
1626 
1627  OptionalNotes getNotes(const PartialDiagnosticAt &Note1,
1628  const PartialDiagnosticAt &Note2) const {
1629  OptionalNotes ONS;
1630  ONS.push_back(Note1);
1631  ONS.push_back(Note2);
1632  if (Verbose && CurrentFunction) {
1633  PartialDiagnosticAt FNote(CurrentFunction->getBody()->getBeginLoc(),
1634  S.PDiag(diag::note_thread_warning_in_fun)
1635  << CurrentFunction);
1636  ONS.push_back(std::move(FNote));
1637  }
1638  return ONS;
1639  }
1640 
1641  OptionalNotes makeLockedHereNote(SourceLocation LocLocked, StringRef Kind) {
1642  return LocLocked.isValid()
1643  ? getNotes(PartialDiagnosticAt(
1644  LocLocked, S.PDiag(diag::note_locked_here) << Kind))
1645  : getNotes();
1646  }
1647 
1648  public:
1649  ThreadSafetyReporter(Sema &S, SourceLocation FL, SourceLocation FEL)
1650  : S(S), FunLocation(FL), FunEndLocation(FEL),
1651  CurrentFunction(nullptr), Verbose(false) {}
1652 
1653  void setVerbose(bool b) { Verbose = b; }
1654 
1655  /// Emit all buffered diagnostics in order of sourcelocation.
1656  /// We need to output diagnostics produced while iterating through
1657  /// the lockset in deterministic order, so this function orders diagnostics
1658  /// and outputs them.
1659  void emitDiagnostics() {
1660  Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1661  for (const auto &Diag : Warnings) {
1662  S.Diag(Diag.first.first, Diag.first.second);
1663  for (const auto &Note : Diag.second)
1664  S.Diag(Note.first, Note.second);
1665  }
1666  }
1667 
1668  void handleInvalidLockExp(StringRef Kind, SourceLocation Loc) override {
1669  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_cannot_resolve_lock)
1670  << Loc);
1671  Warnings.emplace_back(std::move(Warning), getNotes());
1672  }
1673 
1674  void handleUnmatchedUnlock(StringRef Kind, Name LockName,
1675  SourceLocation Loc) override {
1676  if (Loc.isInvalid())
1677  Loc = FunLocation;
1678  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_unlock_but_no_lock)
1679  << Kind << LockName);
1680  Warnings.emplace_back(std::move(Warning), getNotes());
1681  }
1682 
1683  void handleIncorrectUnlockKind(StringRef Kind, Name LockName,
1684  LockKind Expected, LockKind Received,
1685  SourceLocation LocLocked,
1686  SourceLocation LocUnlock) override {
1687  if (LocUnlock.isInvalid())
1688  LocUnlock = FunLocation;
1690  LocUnlock, S.PDiag(diag::warn_unlock_kind_mismatch)
1691  << Kind << LockName << Received << Expected);
1692  Warnings.emplace_back(std::move(Warning),
1693  makeLockedHereNote(LocLocked, Kind));
1694  }
1695 
1696  void handleDoubleLock(StringRef Kind, Name LockName, SourceLocation LocLocked,
1697  SourceLocation LocDoubleLock) override {
1698  if (LocDoubleLock.isInvalid())
1699  LocDoubleLock = FunLocation;
1700  PartialDiagnosticAt Warning(LocDoubleLock, S.PDiag(diag::warn_double_lock)
1701  << Kind << LockName);
1702  Warnings.emplace_back(std::move(Warning),
1703  makeLockedHereNote(LocLocked, Kind));
1704  }
1705 
1706  void handleMutexHeldEndOfScope(StringRef Kind, Name LockName,
1707  SourceLocation LocLocked,
1708  SourceLocation LocEndOfScope,
1709  LockErrorKind LEK) override {
1710  unsigned DiagID = 0;
1711  switch (LEK) {
1713  DiagID = diag::warn_lock_some_predecessors;
1714  break;
1716  DiagID = diag::warn_expecting_lock_held_on_loop;
1717  break;
1719  DiagID = diag::warn_no_unlock;
1720  break;
1722  DiagID = diag::warn_expecting_locked;
1723  break;
1724  }
1725  if (LocEndOfScope.isInvalid())
1726  LocEndOfScope = FunEndLocation;
1727 
1728  PartialDiagnosticAt Warning(LocEndOfScope, S.PDiag(DiagID) << Kind
1729  << LockName);
1730  Warnings.emplace_back(std::move(Warning),
1731  makeLockedHereNote(LocLocked, Kind));
1732  }
1733 
1734  void handleExclusiveAndShared(StringRef Kind, Name LockName,
1735  SourceLocation Loc1,
1736  SourceLocation Loc2) override {
1738  S.PDiag(diag::warn_lock_exclusive_and_shared)
1739  << Kind << LockName);
1740  PartialDiagnosticAt Note(Loc2, S.PDiag(diag::note_lock_exclusive_and_shared)
1741  << Kind << LockName);
1742  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1743  }
1744 
1745  void handleNoMutexHeld(StringRef Kind, const NamedDecl *D,
1747  SourceLocation Loc) override {
1748  assert((POK == POK_VarAccess || POK == POK_VarDereference) &&
1749  "Only works for variables");
1750  unsigned DiagID = POK == POK_VarAccess?
1751  diag::warn_variable_requires_any_lock:
1752  diag::warn_var_deref_requires_any_lock;
1753  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
1754  << D << getLockKindFromAccessKind(AK));
1755  Warnings.emplace_back(std::move(Warning), getNotes());
1756  }
1757 
1758  void handleMutexNotHeld(StringRef Kind, const NamedDecl *D,
1759  ProtectedOperationKind POK, Name LockName,
1760  LockKind LK, SourceLocation Loc,
1761  Name *PossibleMatch) override {
1762  unsigned DiagID = 0;
1763  if (PossibleMatch) {
1764  switch (POK) {
1765  case POK_VarAccess:
1766  DiagID = diag::warn_variable_requires_lock_precise;
1767  break;
1768  case POK_VarDereference:
1769  DiagID = diag::warn_var_deref_requires_lock_precise;
1770  break;
1771  case POK_FunctionCall:
1772  DiagID = diag::warn_fun_requires_lock_precise;
1773  break;
1774  case POK_PassByRef:
1775  DiagID = diag::warn_guarded_pass_by_reference;
1776  break;
1777  case POK_PtPassByRef:
1778  DiagID = diag::warn_pt_guarded_pass_by_reference;
1779  break;
1780  }
1781  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
1782  << D
1783  << LockName << LK);
1784  PartialDiagnosticAt Note(Loc, S.PDiag(diag::note_found_mutex_near_match)
1785  << *PossibleMatch);
1786  if (Verbose && POK == POK_VarAccess) {
1787  PartialDiagnosticAt VNote(D->getLocation(),
1788  S.PDiag(diag::note_guarded_by_declared_here)
1789  << D->getNameAsString());
1790  Warnings.emplace_back(std::move(Warning), getNotes(Note, VNote));
1791  } else
1792  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1793  } else {
1794  switch (POK) {
1795  case POK_VarAccess:
1796  DiagID = diag::warn_variable_requires_lock;
1797  break;
1798  case POK_VarDereference:
1799  DiagID = diag::warn_var_deref_requires_lock;
1800  break;
1801  case POK_FunctionCall:
1802  DiagID = diag::warn_fun_requires_lock;
1803  break;
1804  case POK_PassByRef:
1805  DiagID = diag::warn_guarded_pass_by_reference;
1806  break;
1807  case POK_PtPassByRef:
1808  DiagID = diag::warn_pt_guarded_pass_by_reference;
1809  break;
1810  }
1811  PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << Kind
1812  << D
1813  << LockName << LK);
1814  if (Verbose && POK == POK_VarAccess) {
1816  S.PDiag(diag::note_guarded_by_declared_here));
1817  Warnings.emplace_back(std::move(Warning), getNotes(Note));
1818  } else
1819  Warnings.emplace_back(std::move(Warning), getNotes());
1820  }
1821  }
1822 
1823  void handleNegativeNotHeld(StringRef Kind, Name LockName, Name Neg,
1824  SourceLocation Loc) override {
1826  S.PDiag(diag::warn_acquire_requires_negative_cap)
1827  << Kind << LockName << Neg);
1828  Warnings.emplace_back(std::move(Warning), getNotes());
1829  }
1830 
1831  void handleFunExcludesLock(StringRef Kind, Name FunName, Name LockName,
1832  SourceLocation Loc) override {
1833  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_fun_excludes_mutex)
1834  << Kind << FunName << LockName);
1835  Warnings.emplace_back(std::move(Warning), getNotes());
1836  }
1837 
1838  void handleLockAcquiredBefore(StringRef Kind, Name L1Name, Name L2Name,
1839  SourceLocation Loc) override {
1841  S.PDiag(diag::warn_acquired_before) << Kind << L1Name << L2Name);
1842  Warnings.emplace_back(std::move(Warning), getNotes());
1843  }
1844 
1845  void handleBeforeAfterCycle(Name L1Name, SourceLocation Loc) override {
1847  S.PDiag(diag::warn_acquired_before_after_cycle) << L1Name);
1848  Warnings.emplace_back(std::move(Warning), getNotes());
1849  }
1850 
1851  void enterFunction(const FunctionDecl* FD) override {
1852  CurrentFunction = FD;
1853  }
1854 
1855  void leaveFunction(const FunctionDecl* FD) override {
1856  CurrentFunction = nullptr;
1857  }
1858 };
1859 } // anonymous namespace
1860 } // namespace threadSafety
1861 } // namespace clang
1862 
1863 //===----------------------------------------------------------------------===//
1864 // -Wconsumed
1865 //===----------------------------------------------------------------------===//
1866 
1867 namespace clang {
1868 namespace consumed {
1869 namespace {
1870 class ConsumedWarningsHandler : public ConsumedWarningsHandlerBase {
1871 
1872  Sema &S;
1873  DiagList Warnings;
1874 
1875 public:
1876 
1877  ConsumedWarningsHandler(Sema &S) : S(S) {}
1878 
1879  void emitDiagnostics() override {
1880  Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
1881  for (const auto &Diag : Warnings) {
1882  S.Diag(Diag.first.first, Diag.first.second);
1883  for (const auto &Note : Diag.second)
1884  S.Diag(Note.first, Note.second);
1885  }
1886  }
1887 
1888  void warnLoopStateMismatch(SourceLocation Loc,
1889  StringRef VariableName) override {
1890  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_loop_state_mismatch) <<
1891  VariableName);
1892 
1893  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1894  }
1895 
1896  void warnParamReturnTypestateMismatch(SourceLocation Loc,
1897  StringRef VariableName,
1898  StringRef ExpectedState,
1899  StringRef ObservedState) override {
1900 
1902  diag::warn_param_return_typestate_mismatch) << VariableName <<
1903  ExpectedState << ObservedState);
1904 
1905  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1906  }
1907 
1908  void warnParamTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
1909  StringRef ObservedState) override {
1910 
1912  diag::warn_param_typestate_mismatch) << ExpectedState << ObservedState);
1913 
1914  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1915  }
1916 
1917  void warnReturnTypestateForUnconsumableType(SourceLocation Loc,
1918  StringRef TypeName) override {
1920  diag::warn_return_typestate_for_unconsumable_type) << TypeName);
1921 
1922  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1923  }
1924 
1925  void warnReturnTypestateMismatch(SourceLocation Loc, StringRef ExpectedState,
1926  StringRef ObservedState) override {
1927 
1929  diag::warn_return_typestate_mismatch) << ExpectedState << ObservedState);
1930 
1931  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1932  }
1933 
1934  void warnUseOfTempInInvalidState(StringRef MethodName, StringRef State,
1935  SourceLocation Loc) override {
1936 
1938  diag::warn_use_of_temp_in_invalid_state) << MethodName << State);
1939 
1940  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1941  }
1942 
1943  void warnUseInInvalidState(StringRef MethodName, StringRef VariableName,
1944  StringRef State, SourceLocation Loc) override {
1945 
1946  PartialDiagnosticAt Warning(Loc, S.PDiag(diag::warn_use_in_invalid_state) <<
1947  MethodName << VariableName << State);
1948 
1949  Warnings.emplace_back(std::move(Warning), OptionalNotes());
1950  }
1951 };
1952 } // anonymous namespace
1953 } // namespace consumed
1954 } // namespace clang
1955 
1956 //===----------------------------------------------------------------------===//
1957 // AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
1958 // warnings on a function, method, or block.
1959 //===----------------------------------------------------------------------===//
1960 
1962  enableCheckFallThrough = 1;
1963  enableCheckUnreachable = 0;
1964  enableThreadSafetyAnalysis = 0;
1965  enableConsumedAnalysis = 0;
1966 }
1967 
1968 static unsigned isEnabled(DiagnosticsEngine &D, unsigned diag) {
1969  return (unsigned)!D.isIgnored(diag, SourceLocation());
1970 }
1971 
1973  : S(s),
1974  NumFunctionsAnalyzed(0),
1975  NumFunctionsWithBadCFGs(0),
1976  NumCFGBlocks(0),
1977  MaxCFGBlocksPerFunction(0),
1978  NumUninitAnalysisFunctions(0),
1979  NumUninitAnalysisVariables(0),
1980  MaxUninitAnalysisVariablesPerFunction(0),
1981  NumUninitAnalysisBlockVisits(0),
1982  MaxUninitAnalysisBlockVisitsPerFunction(0) {
1983 
1984  using namespace diag;
1986 
1987  DefaultPolicy.enableCheckUnreachable =
1988  isEnabled(D, warn_unreachable) ||
1989  isEnabled(D, warn_unreachable_break) ||
1990  isEnabled(D, warn_unreachable_return) ||
1991  isEnabled(D, warn_unreachable_loop_increment);
1992 
1993  DefaultPolicy.enableThreadSafetyAnalysis =
1994  isEnabled(D, warn_double_lock);
1995 
1996  DefaultPolicy.enableConsumedAnalysis =
1997  isEnabled(D, warn_use_in_invalid_state);
1998 }
1999 
2000 static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope) {
2001  for (const auto &D : fscope->PossiblyUnreachableDiags)
2002  S.Diag(D.Loc, D.PD);
2003 }
2004 
2005 void clang::sema::
2007  sema::FunctionScopeInfo *fscope,
2008  const Decl *D, QualType BlockType) {
2009 
2010  // We avoid doing analysis-based warnings when there are errors for
2011  // two reasons:
2012  // (1) The CFGs often can't be constructed (if the body is invalid), so
2013  // don't bother trying.
2014  // (2) The code already has problems; running the analysis just takes more
2015  // time.
2016  DiagnosticsEngine &Diags = S.getDiagnostics();
2017 
2018  // Do not do any analysis if we are going to just ignore them.
2019  if (Diags.getIgnoreAllWarnings() ||
2020  (Diags.getSuppressSystemWarnings() &&
2022  return;
2023 
2024  // For code in dependent contexts, we'll do this at instantiation time.
2025  if (cast<DeclContext>(D)->isDependentContext())
2026  return;
2027 
2028  if (Diags.hasUncompilableErrorOccurred()) {
2029  // Flush out any possibly unreachable diagnostics.
2030  flushDiagnostics(S, fscope);
2031  return;
2032  }
2033 
2034  const Stmt *Body = D->getBody();
2035  assert(Body);
2036 
2037  // Construct the analysis context with the specified CFG build options.
2038  AnalysisDeclContext AC(/* AnalysisDeclContextManager */ nullptr, D);
2039 
2040  // Don't generate EH edges for CallExprs as we'd like to avoid the n^2
2041  // explosion for destructors that can result and the compile time hit.
2043  AC.getCFGBuildOptions().AddEHEdges = false;
2044  AC.getCFGBuildOptions().AddInitializers = true;
2049 
2050  // Force that certain expressions appear as CFGElements in the CFG. This
2051  // is used to speed up various analyses.
2052  // FIXME: This isn't the right factoring. This is here for initial
2053  // prototyping, but we need a way for analyses to say what expressions they
2054  // expect to always be CFGElements and then fill in the BuildOptions
2055  // appropriately. This is essentially a layering violation.
2056  if (P.enableCheckUnreachable || P.enableThreadSafetyAnalysis ||
2057  P.enableConsumedAnalysis) {
2058  // Unreachable code analysis and thread safety require a linearized CFG.
2060  }
2061  else {
2062  AC.getCFGBuildOptions()
2063  .setAlwaysAdd(Stmt::BinaryOperatorClass)
2064  .setAlwaysAdd(Stmt::CompoundAssignOperatorClass)
2065  .setAlwaysAdd(Stmt::BlockExprClass)
2066  .setAlwaysAdd(Stmt::CStyleCastExprClass)
2067  .setAlwaysAdd(Stmt::DeclRefExprClass)
2068  .setAlwaysAdd(Stmt::ImplicitCastExprClass)
2069  .setAlwaysAdd(Stmt::UnaryOperatorClass)
2070  .setAlwaysAdd(Stmt::AttributedStmtClass);
2071  }
2072 
2073  // Install the logical handler for -Wtautological-overlap-compare
2075  if (!Diags.isIgnored(diag::warn_tautological_overlap_comparison,
2076  D->getBeginLoc())) {
2077  LEH.emplace(S);
2078  AC.getCFGBuildOptions().Observer = &*LEH;
2079  }
2080 
2081  // Emit delayed diagnostics.
2082  if (!fscope->PossiblyUnreachableDiags.empty()) {
2083  bool analyzed = false;
2084 
2085  // Register the expressions with the CFGBuilder.
2086  for (const auto &D : fscope->PossiblyUnreachableDiags) {
2087  for (const Stmt *S : D.Stmts)
2089  }
2090 
2091  if (AC.getCFG()) {
2092  analyzed = true;
2093  for (const auto &D : fscope->PossiblyUnreachableDiags) {
2094  bool AllReachable = true;
2095  for (const Stmt *S : D.Stmts) {
2096  const CFGBlock *block = AC.getBlockForRegisteredExpression(S);
2099  // FIXME: We should be able to assert that block is non-null, but
2100  // the CFG analysis can skip potentially-evaluated expressions in
2101  // edge cases; see test/Sema/vla-2.c.
2102  if (block && cra) {
2103  // Can this block be reached from the entrance?
2104  if (!cra->isReachable(&AC.getCFG()->getEntry(), block)) {
2105  AllReachable = false;
2106  break;
2107  }
2108  }
2109  // If we cannot map to a basic block, assume the statement is
2110  // reachable.
2111  }
2112 
2113  if (AllReachable)
2114  S.Diag(D.Loc, D.PD);
2115  }
2116  }
2117 
2118  if (!analyzed)
2119  flushDiagnostics(S, fscope);
2120  }
2121 
2122  // Warning: check missing 'return'
2123  if (P.enableCheckFallThrough) {
2124  const CheckFallThroughDiagnostics &CD =
2125  (isa<BlockDecl>(D)
2126  ? CheckFallThroughDiagnostics::MakeForBlock()
2127  : (isa<CXXMethodDecl>(D) &&
2128  cast<CXXMethodDecl>(D)->getOverloadedOperator() == OO_Call &&
2129  cast<CXXMethodDecl>(D)->getParent()->isLambda())
2130  ? CheckFallThroughDiagnostics::MakeForLambda()
2131  : (fscope->isCoroutine()
2132  ? CheckFallThroughDiagnostics::MakeForCoroutine(D)
2133  : CheckFallThroughDiagnostics::MakeForFunction(D)));
2134  CheckFallThroughForBody(S, D, Body, BlockType, CD, AC, fscope);
2135  }
2136 
2137  // Warning: check for unreachable code
2138  if (P.enableCheckUnreachable) {
2139  // Only check for unreachable code on non-template instantiations.
2140  // Different template instantiations can effectively change the control-flow
2141  // and it is very difficult to prove that a snippet of code in a template
2142  // is unreachable for all instantiations.
2143  bool isTemplateInstantiation = false;
2144  if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
2145  isTemplateInstantiation = Function->isTemplateInstantiation();
2146  if (!isTemplateInstantiation)
2147  CheckUnreachable(S, AC);
2148  }
2149 
2150  // Check for thread safety violations
2151  if (P.enableThreadSafetyAnalysis) {
2152  SourceLocation FL = AC.getDecl()->getLocation();
2153  SourceLocation FEL = AC.getDecl()->getEndLoc();
2154  threadSafety::ThreadSafetyReporter Reporter(S, FL, FEL);
2155  if (!Diags.isIgnored(diag::warn_thread_safety_beta, D->getBeginLoc()))
2156  Reporter.setIssueBetaWarnings(true);
2157  if (!Diags.isIgnored(diag::warn_thread_safety_verbose, D->getBeginLoc()))
2158  Reporter.setVerbose(true);
2159 
2162  Reporter.emitDiagnostics();
2163  }
2164 
2165  // Check for violations of consumed properties.
2166  if (P.enableConsumedAnalysis) {
2167  consumed::ConsumedWarningsHandler WarningHandler(S);
2168  consumed::ConsumedAnalyzer Analyzer(WarningHandler);
2169  Analyzer.run(AC);
2170  }
2171 
2172  if (!Diags.isIgnored(diag::warn_uninit_var, D->getBeginLoc()) ||
2173  !Diags.isIgnored(diag::warn_sometimes_uninit_var, D->getBeginLoc()) ||
2174  !Diags.isIgnored(diag::warn_maybe_uninit_var, D->getBeginLoc())) {
2175  if (CFG *cfg = AC.getCFG()) {
2176  UninitValsDiagReporter reporter(S);
2178  std::memset(&stats, 0, sizeof(UninitVariablesAnalysisStats));
2179  runUninitializedVariablesAnalysis(*cast<DeclContext>(D), *cfg, AC,
2180  reporter, stats);
2181 
2182  if (S.CollectStats && stats.NumVariablesAnalyzed > 0) {
2183  ++NumUninitAnalysisFunctions;
2184  NumUninitAnalysisVariables += stats.NumVariablesAnalyzed;
2185  NumUninitAnalysisBlockVisits += stats.NumBlockVisits;
2186  MaxUninitAnalysisVariablesPerFunction =
2187  std::max(MaxUninitAnalysisVariablesPerFunction,
2188  stats.NumVariablesAnalyzed);
2189  MaxUninitAnalysisBlockVisitsPerFunction =
2190  std::max(MaxUninitAnalysisBlockVisitsPerFunction,
2191  stats.NumBlockVisits);
2192  }
2193  }
2194  }
2195 
2196  bool FallThroughDiagFull =
2197  !Diags.isIgnored(diag::warn_unannotated_fallthrough, D->getBeginLoc());
2198  bool FallThroughDiagPerFunction = !Diags.isIgnored(
2199  diag::warn_unannotated_fallthrough_per_function, D->getBeginLoc());
2200  if (FallThroughDiagFull || FallThroughDiagPerFunction ||
2201  fscope->HasFallthroughStmt) {
2202  DiagnoseSwitchLabelsFallthrough(S, AC, !FallThroughDiagFull);
2203  }
2204 
2205  if (S.getLangOpts().ObjCWeak &&
2206  !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, D->getBeginLoc()))
2207  diagnoseRepeatedUseOfWeak(S, fscope, D, AC.getParentMap());
2208 
2209 
2210  // Check for infinite self-recursion in functions
2211  if (!Diags.isIgnored(diag::warn_infinite_recursive_function,
2212  D->getBeginLoc())) {
2213  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
2214  checkRecursiveFunction(S, FD, Body, AC);
2215  }
2216  }
2217 
2218  // Check for throw out of non-throwing function.
2219  if (!Diags.isIgnored(diag::warn_throw_in_noexcept_func, D->getBeginLoc()))
2220  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
2221  if (S.getLangOpts().CPlusPlus && isNoexcept(FD))
2222  checkThrowInNonThrowingFunc(S, FD, AC);
2223 
2224  // If none of the previous checks caused a CFG build, trigger one here
2225  // for -Wtautological-overlap-compare
2226  if (!Diags.isIgnored(diag::warn_tautological_overlap_comparison,
2227  D->getBeginLoc())) {
2228  AC.getCFG();
2229  }
2230 
2231  // Collect statistics about the CFG if it was built.
2232  if (S.CollectStats && AC.isCFGBuilt()) {
2233  ++NumFunctionsAnalyzed;
2234  if (CFG *cfg = AC.getCFG()) {
2235  // If we successfully built a CFG for this context, record some more
2236  // detail information about it.
2237  NumCFGBlocks += cfg->getNumBlockIDs();
2238  MaxCFGBlocksPerFunction = std::max(MaxCFGBlocksPerFunction,
2239  cfg->getNumBlockIDs());
2240  } else {
2241  ++NumFunctionsWithBadCFGs;
2242  }
2243  }
2244 }
2245 
2247  llvm::errs() << "\n*** Analysis Based Warnings Stats:\n";
2248 
2249  unsigned NumCFGsBuilt = NumFunctionsAnalyzed - NumFunctionsWithBadCFGs;
2250  unsigned AvgCFGBlocksPerFunction =
2251  !NumCFGsBuilt ? 0 : NumCFGBlocks/NumCFGsBuilt;
2252  llvm::errs() << NumFunctionsAnalyzed << " functions analyzed ("
2253  << NumFunctionsWithBadCFGs << " w/o CFGs).\n"
2254  << " " << NumCFGBlocks << " CFG blocks built.\n"
2255  << " " << AvgCFGBlocksPerFunction
2256  << " average CFG blocks per function.\n"
2257  << " " << MaxCFGBlocksPerFunction
2258  << " max CFG blocks per function.\n";
2259 
2260  unsigned AvgUninitVariablesPerFunction = !NumUninitAnalysisFunctions ? 0
2261  : NumUninitAnalysisVariables/NumUninitAnalysisFunctions;
2262  unsigned AvgUninitBlockVisitsPerFunction = !NumUninitAnalysisFunctions ? 0
2263  : NumUninitAnalysisBlockVisits/NumUninitAnalysisFunctions;
2264  llvm::errs() << NumUninitAnalysisFunctions
2265  << " functions analyzed for uninitialiazed variables\n"
2266  << " " << NumUninitAnalysisVariables << " variables analyzed.\n"
2267  << " " << AvgUninitVariablesPerFunction
2268  << " average variables per function.\n"
2269  << " " << MaxUninitAnalysisVariablesPerFunction
2270  << " max variables per function.\n"
2271  << " " << NumUninitAnalysisBlockVisits << " block visits.\n"
2272  << " " << AvgUninitBlockVisitsPerFunction
2273  << " average block visits per function.\n"
2274  << " " << MaxUninitAnalysisBlockVisitsPerFunction
2275  << " max block visits per function.\n";
2276 }
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:1784
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:939
A (possibly-)qualified type.
Definition: Type.h:643
bool isBlockPointerType() const
Definition: Type.h:6399
SourceLocation getExprLoc() const
Definition: Expr.h:3440
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:127
const Expr * getSubExpr() const
Definition: ExprCXX.h:1071
const Stmt * getStmt() const
Definition: CFG.h:138
Stmt * getBody() const
Get the body of the Declaration.
succ_iterator succ_begin()
Definition: CFG.h:956
virtual Stmt * getBody() const
getBody - If this Decl represents a declaration for a body of code, such as a function or method defi...
Definition: DeclBase.h:986
Stmt - This represents one statement.
Definition: Stmt.h:66
FunctionType - C99 6.7.5.3 - Function Declarators.
Definition: Type.h:3393
CFGBlock & getEntry()
Definition: CFG.h:1316
IfStmt - This represents an if/then/else.
Definition: Stmt.h:1812
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:557
llvm::Expected< T > Expected
Defines the SourceManager interface.
static void diagnoseRepeatedUseOfWeak(Sema &S, const sema::FunctionScopeInfo *CurFn, const Decl *D, const ParentMap &PM)
unsigned getBlockID() const
Definition: CFG.h:1075
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID)
Emit a diagnostic.
Definition: Sema.h:1371
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
Expr * getImplicitObjectArgument() const
Retrieve the implicit object argument for the member call.
Definition: ExprCXX.cpp:648
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: DeclBase.h:421
bool isVirtual() const
Definition: DeclCXX.h:1935
Opcode getOpcode() const
Definition: Expr.h:3444
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:1754
bool isBeforeInTranslationUnit(SourceLocation LHS, SourceLocation RHS) const
Determines the order of 2 source locations in the translation unit.
bool getAddEHEdges() const
getAddEHEdges - Return true iff we are adding exceptional edges from callExprs.
const WeakObjectUseMap & getWeakObjectUses() const
Definition: ScopeInfo.h:392
The use is uninitialized whenever a certain branch is taken.
Stmt * getParent(Stmt *) const
Definition: ParentMap.cpp:134
iterator begin()
Definition: CFG.h:876
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:49
SourceLocation getEndLoc() const LLVM_READONLY
Definition: DeclBase.h:425
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:628
LockKind getLockKindFromAccessKind(AccessKind AK)
Helper function that returns a LockKind required for the given level of access.
unsigned IgnoreDefaultsWithCoveredEnums
Definition: CFG.h:984
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:97
Represents a variable declaration or definition.
Definition: Decl.h:827
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:6858
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:138
The use might be uninitialized.
Stmt * getThen()
Definition: Stmt.h:1899
Defines the Objective-C statement AST node classes.
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1049
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:1710
LockKind
This enum distinguishes between different kinds of lock actions.
Definition: ThreadSafety.h:56
bool pred_empty() const
Definition: CFG.h:978
DeclarationName getDeclName() const
Get the actual, stored name of the declaration, which may be a special name.
Definition: Decl.h:297
Kind getKind() const
Get the kind of uninitialized use.
Expr * getFalseExpr() const
Definition: Expr.h:3750
SourceLocation getBegin() const
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:160
LineState State
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Stmt.cpp:274
branch_iterator branch_begin() const
Branches which inevitably result in the variable being used uninitialized.
AnalysisDeclContext contains the context data for the function or method under analysis.
threadSafety::BeforeSet * ThreadSafetyDeclCache
Definition: Sema.h:7994
static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC, bool PerFunction)
succ_range succs()
Definition: CFG.h:966
__DEVICE__ int max(int __a, int __b)
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Decl.h:746
const LangOptions & getLangOpts() const
Definition: Preprocessor.h:904
AdjacentBlocks::const_iterator const_succ_iterator
Definition: CFG.h:932
TextDiagnosticBuffer::DiagList DiagList
Stmt * getBody(const FunctionDecl *&Definition) const
Retrieve the body (definition) of the function.
Definition: Decl.cpp:2847
APValue Val
Val - This is the value the expression can be folded to.
Definition: Expr.h:582
bool AddCXXDefaultInitExprInCtors
Definition: CFG.h:1249
CFGReverseBlockReachabilityAnalysis * getCFGReachablityAnalysis()
CFGCallback * Observer
Definition: CFG.h:1238
child_range children()
Definition: Stmt.cpp:223
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:149
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3409
static StringRef getFallthroughAttrSpelling(Preprocessor &PP, SourceLocation Loc)
SourceLocation getThrowLoc() const
Definition: ExprCXX.h:1074
Expr * IgnoreParenCasts() LLVM_READONLY
Skip past any parentheses and casts which might surround this expression until reaching a fixed point...
Definition: Expr.cpp:2971
static void CheckUnreachable(Sema &S, AnalysisDeclContext &AC)
CheckUnreachable - Check for unreachable code.
DeclContext * getLexicalDeclContext()
getLexicalDeclContext - The declaration context where this Decl was lexically declared (LexicalDC)...
Definition: DeclBase.h:828
__DEVICE__ void * memset(void *__a, int __b, size_t __c)
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1727
const LangOptions & getLangOpts() const
Definition: Sema.h:1284
SourceRange getExceptionSpecSourceRange() const
Attempt to compute an informative source range covering the function exception specification, if any.
Definition: Decl.cpp:3343
A class that does preorder or postorder depth-first traversal on the entire Clang AST and visits each...
virtual Decl * getCanonicalDecl()
Retrieves the "canonical" declaration of the given declaration.
Definition: DeclBase.h:877
reverse_iterator rend()
Definition: CFG.h:882
static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD)
DiagnosticsEngine & getDiagnostics() const
Definition: Sema.h:1288
Passing a pt-guarded variable by reference.
Definition: ThreadSafety.h:50
bool hasAttr() const
Definition: DeclBase.h:542
ConditionalOperator - The ?: ternary operator.
Definition: Expr.h:3707
Sema - This implements semantic analysis and AST building for C.
Definition: Sema.h:329
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3725
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:2030
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:3741
This represents one expression.
Definition: Expr.h:108
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:751
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6923
#define V(N, I)
Definition: ASTContext.h:2921
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5551
Expr * getCallee()
Definition: Expr.h:2638
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:3073
Stores token information for comparing actual tokens with predefined values.
Definition: Preprocessor.h:86
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:137
std::pair< PartialDiagnosticAt, OptionalNotes > DelayedDiag
Definition: Consumed.h:53
const CFGBlock * getBlockForRegisteredExpression(const Stmt *stmt)
bool handlerCanCatch(QualType HandlerType, QualType ExceptionType)
AccessKind
This enum distinguishes between different ways to access (read or write) a variable.
Definition: ThreadSafety.h:69
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:667
Preprocessor & getPreprocessor() const
Definition: Sema.h:1290
Expr * getCond()
Definition: Stmt.h:1887
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:708
bool isTemplateInstantiation(TemplateSpecializationKind Kind)
Determine whether this template specialization kind refers to an instantiation of an entity (as oppos...
Definition: Specifiers.h:199
reverse_iterator rbegin()
Definition: CFG.h:881
VarDecl * CoroutinePromise
The promise object for this coroutine, if any.
Definition: ScopeInfo.h:193
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:70
Kind
QualType getCanonicalType() const
Definition: Type.h:6187
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:1291
Encodes a location in the source.
BuildOptions & setAlwaysAdd(Stmt::StmtClass stmtClass, bool val=true)
Definition: CFG.h:1260
static void visitReachableThrows(CFG *BodyCFG, llvm::function_ref< void(const CXXThrowExpr *, CFGBlock &)> Visit)
SourceLocation getOperatorLoc() const
Definition: Expr.h:3441
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Expr.h:5574
static void EmitDiagForCXXThrowInNonThrowingFunc(Sema &S, SourceLocation OpLoc, const FunctionDecl *FD)
Stmt * getLabel()
Definition: CFG.h:1070
std::string getNameAsString() const
Get a human-readable name for the declaration, even if it is one of the special kinds of names (C++ c...
Definition: Decl.h:291
bool isReachable(const CFGBlock *Src, const CFGBlock *Dst)
Returns true if the block &#39;Dst&#39; can be reached from block &#39;Src&#39;.
Represents a call to a member function that may be written either with member call syntax (e...
Definition: ExprCXX.h:170
llvm::iterator_range< capture_init_iterator > capture_inits()
Retrieve the initialization expressions for this lambda&#39;s captures.
Definition: ExprCXX.h:1861
Stmt * getElse()
Definition: Stmt.h:1908
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:1892
bool isCFGBuilt() const
Returns true if we have built a CFG for this analysis context.
Represents a C++ nested name specifier, such as "\::std::vector<int>::".
bool CollectStats
Flag indicating whether or not to collect detailed statistics.
Definition: Sema.h:381
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:728
unsigned getNumBlockIDs() const
Returns the total number of BlockIDs allocated (which start at 0).
Definition: CFG.h:1392
SourceRange getSourceRange() const override LLVM_READONLY
Source range that this declaration covers.
Definition: Decl.cpp:2003
static bool isLogicalOp(Opcode Opc)
Definition: Expr.h:3532
static void emitDiagnostics(BoundNodes &Match, const Decl *D, BugReporter &BR, AnalysisManager &AM, const ObjCAutoreleaseWriteChecker *Checker)
succ_iterator succ_end()
Definition: CFG.h:957
BuildOptions & setAllAlwaysAdd()
Definition: CFG.h:1265
The use is uninitialized the first time it is reached after we reach the variable&#39;s declaration...
Stmt * getSubStmt()
Definition: Stmt.h:1677
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:221
bool getIgnoreAllWarnings() const
Definition: Diagnostic.h:591
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:3449
pred_iterator pred_begin()
Definition: CFG.h:938
SmallVectorImpl< Branch >::const_iterator branch_iterator
Dataflow Directional Tag Classes.
CFG::BuildOptions & getCFGBuildOptions()
Return the build options used to construct the CFG.
bool isValid() const
Return true if this is a valid SourceLocation object.
EvalResult is a struct with detailed info about an evaluated expression.
Definition: Expr.h:580
void runThreadSafetyAnalysis(AnalysisDeclContext &AC, ThreadSafetyHandler &Handler, BeforeSet **Bset)
Check a function&#39;s CFG for thread-safety violations.
static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then, const Stmt *Else, bool CondVal, FixItHint &Fixit1, FixItHint &Fixit2)
Create a fixit to remove an if-like statement, on the assumption that its condition is CondVal...
static FixItHint CreateRemoval(CharSourceRange RemoveRange)
Create a code modification hint that removes the given source range.
Definition: Diagnostic.h:118
const Expr * getInit() const
Definition: Decl.h:1234
static bool checkForRecursiveFunctionCall(const FunctionDecl *FD, CFG *cfg)
StmtClass getStmtClass() const
Definition: Stmt.h:1087
Represents a simple identification of a weak object.
Definition: ScopeInfo.h:244
Stmt * getTerminatorStmt()
Definition: CFG.h:1051
A class that handles the analysis of uniqueness violations.
Definition: Consumed.h:240
bool hasObjCLifetime() const
Definition: Type.h:326
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:2966
bool isMacroID() const
SwitchStmt - This represents a &#39;switch&#39; stmt.
Definition: Stmt.h:2017
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:723
static bool throwEscapes(Sema &S, const CXXThrowExpr *E, CFGBlock &ThrowBlock, CFG *Body)
Determine whether an exception thrown by E, unwinding from ThrowBlock, can reach ExitBlock.
static void checkRecursiveFunction(Sema &S, const FunctionDecl *FD, const Stmt *Body, AnalysisDeclContext &AC)
static FixItHint CreateInsertion(SourceLocation InsertionLoc, StringRef Code, bool BeforePreviousInsertions=false)
Create a code modification hint that inserts the given code string at a specific location.
Definition: Diagnostic.h:92
static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope)
bool hasNoReturnElement() const
Definition: CFG.h:1073
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:215
CFGCallback defines methods that should be called when a logical operator error is found when buildin...
Definition: CFG.h:1208
bool isValid() const
Expr * getTrueExpr() const
Definition: Expr.h:3745
bool LE(InterpState &S, CodePtr OpPC)
Definition: Interp.h:240
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:6175
Represents a top-level expression in a basic block.
Definition: CFG.h:55
static FixItHint CreateReplacement(CharSourceRange RemoveRange, StringRef Code)
Create a code modification hint that replaces the given source range with the given code string...
Definition: Diagnostic.h:129
capture_range captures() const
Retrieve this lambda&#39;s captures.
Definition: ExprCXX.cpp:1182
SourceManager & getSourceManager() const
Definition: Sema.h:1289
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:262
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:2521
void registerForcedBlockExpression(const Stmt *stmt)
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Expr.h:3454
llvm::SmallDenseMap< WeakObjectProfileTy, WeakUseVector, 8, WeakObjectProfileTy::DenseMapInfo > WeakObjectUseMap
Used to collect all uses of weak objects in a function body.
Definition: ScopeInfo.h:353
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1146
bool isIgnored(unsigned DiagID, SourceLocation Loc) const
Determine whether the diagnostic is known to be ignored.
Definition: Diagnostic.h:819
TemplatedKind getTemplatedKind() const
What kind of templated function this is.
Definition: Decl.cpp:3440
SourceManager & SourceMgr
Definition: Sema.h:378
Annotates a diagnostic with some code that should be inserted, removed, or replaced to fix the proble...
Definition: Diagnostic.h:66
Stmt * getSubStmt()
Definition: Stmt.h:1731
QualType getType() const
Definition: Decl.h:655
A trivial tuple used to represent a source range.
ASTContext & Context
Definition: Sema.h:375
FunctionDecl * getCanonicalDecl() override
Retrieves the "canonical" declaration of the given declaration.
Definition: Decl.cpp:3100
This represents a decl that may have a name.
Definition: Decl.h:248
iterator end()
Definition: CFG.h:877
APSInt & getInt()
Definition: APValue.h:380
Decl * getCalleeDecl()
Definition: Expr.h:2650
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:429
QualType getType() const
Return the type wrapped by this type source info.
Definition: Decl.h:97
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:125
CFGBlock & getExit()
Definition: CFG.h:1318