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1//===----------------------------------------------------------------------===//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-exception6//7//===----------------------------------------------------------------------===//8 9#include "ExceptionAnalyzer.h"10 11namespace clang::tidy::utils {12 13void ExceptionAnalyzer::ExceptionInfo::registerException(14    const Type *ExceptionType, const ThrowInfo &ThrowInfo) {15  assert(ExceptionType != nullptr && "Only valid types are accepted");16  Behaviour = State::Throwing;17  ThrownExceptions.insert({ExceptionType, ThrowInfo});18}19 20void ExceptionAnalyzer::ExceptionInfo::registerExceptions(21    const Throwables &Exceptions) {22  if (Exceptions.empty())23    return;24  Behaviour = State::Throwing;25  ThrownExceptions.insert_range(Exceptions);26}27 28ExceptionAnalyzer::ExceptionInfo &ExceptionAnalyzer::ExceptionInfo::merge(29    const ExceptionAnalyzer::ExceptionInfo &Other) {30  // Only the following two cases require an update to the local31  // 'Behaviour'. If the local entity is already throwing there will be no32  // change and if the other entity is throwing the merged entity will throw33  // as well.34  // If one of both entities is 'Unknown' and the other one does not throw35  // the merged entity is 'Unknown' as well.36  if (Other.Behaviour == State::Throwing)37    Behaviour = State::Throwing;38  else if (Other.Behaviour == State::Unknown && Behaviour == State::NotThrowing)39    Behaviour = State::Unknown;40 41  ContainsUnknown = ContainsUnknown || Other.ContainsUnknown;42  ThrownExceptions.insert_range(Other.ThrownExceptions);43  return *this;44}45 46// FIXME: This could be ported to clang later.47 48static bool isUnambiguousPublicBaseClass(const Type *DerivedType,49                                         const Type *BaseType) {50  const auto *DerivedClass =51      DerivedType->getCanonicalTypeUnqualified()->getAsCXXRecordDecl();52  const auto *BaseClass =53      BaseType->getCanonicalTypeUnqualified()->getAsCXXRecordDecl();54  if (!DerivedClass || !BaseClass)55    return false;56 57  CXXBasePaths Paths;58  Paths.setOrigin(DerivedClass);59 60  bool IsPublicBaseClass = false;61  DerivedClass->lookupInBases(62      [&BaseClass, &IsPublicBaseClass](const CXXBaseSpecifier *BS,63                                       CXXBasePath &) {64        if (BS->getType()65                    ->getCanonicalTypeUnqualified()66                    ->getAsCXXRecordDecl() == BaseClass &&67            BS->getAccessSpecifier() == AS_public) {68          IsPublicBaseClass = true;69          return true;70        }71 72        return false;73      },74      Paths);75 76  return !Paths.isAmbiguous(BaseType->getCanonicalTypeUnqualified()) &&77         IsPublicBaseClass;78}79 80static bool isPointerOrPointerToMember(const Type *T) {81  return T->isPointerType() || T->isMemberPointerType();82}83 84static std::optional<QualType> getPointeeOrArrayElementQualType(QualType T) {85  if (T->isAnyPointerType() || T->isMemberPointerType())86    return T->getPointeeType();87 88  if (T->isArrayType())89    return T->getAsArrayTypeUnsafe()->getElementType();90 91  return std::nullopt;92}93 94static bool isBaseOf(const Type *DerivedType, const Type *BaseType) {95  const auto *DerivedClass = DerivedType->getAsCXXRecordDecl();96  const auto *BaseClass = BaseType->getAsCXXRecordDecl();97  if (!DerivedClass || !BaseClass)98    return false;99 100  return !DerivedClass->forallBases(101      [BaseClass](const CXXRecordDecl *Cur) { return Cur != BaseClass; });102}103 104// Check if T1 is more or Equally qualified than T2.105static bool moreOrEquallyQualified(QualType T1, QualType T2) {106  return T1.getQualifiers().isStrictSupersetOf(T2.getQualifiers()) ||107         T1.getQualifiers() == T2.getQualifiers();108}109 110static bool isStandardPointerConvertible(QualType From, QualType To) {111  assert((From->isPointerType() || From->isMemberPointerType()) &&112         (To->isPointerType() || To->isMemberPointerType()) &&113         "Pointer conversion should be performed on pointer types only.");114 115  if (!moreOrEquallyQualified(To->getPointeeType(), From->getPointeeType()))116    return false;117 118  // (1)119  // A null pointer constant can be converted to a pointer type ...120  // The conversion of a null pointer constant to a pointer to cv-qualified type121  // is a single conversion, and not the sequence of a pointer conversion122  // followed by a qualification conversion. A null pointer constant of integral123  // type can be converted to a prvalue of type std::nullptr_t124  if (To->isPointerType() && From->isNullPtrType())125    return true;126 127  // (2)128  // A prvalue of type “pointer to cv T”, where T is an object type, can be129  // converted to a prvalue of type “pointer to cv void”.130  if (To->isVoidPointerType() && From->isObjectPointerType())131    return true;132 133  // (3)134  // A prvalue of type “pointer to cv D”, where D is a complete class type, can135  // be converted to a prvalue of type “pointer to cv B”, where B is a base136  // class of D. If B is an inaccessible or ambiguous base class of D, a program137  // that necessitates this conversion is ill-formed.138  if (const auto *RD = From->getPointeeCXXRecordDecl()) {139    if (RD->isCompleteDefinition() &&140        isBaseOf(From->getPointeeType().getTypePtr(),141                 To->getPointeeType().getTypePtr())) {142      // If B is an inaccessible or ambiguous base class of D, a program143      // that necessitates this conversion is ill-formed144      return isUnambiguousPublicBaseClass(From->getPointeeType().getTypePtr(),145                                          To->getPointeeType().getTypePtr());146    }147  }148 149  return false;150}151 152static bool isFunctionPointerConvertible(QualType From, QualType To) {153  if (!From->isFunctionPointerType() && !From->isFunctionType() &&154      !From->isMemberFunctionPointerType())155    return false;156 157  if (!To->isFunctionPointerType() && !To->isMemberFunctionPointerType())158    return false;159 160  if (To->isFunctionPointerType()) {161    if (From->isFunctionPointerType())162      return To->getPointeeType() == From->getPointeeType();163 164    if (From->isFunctionType())165      return To->getPointeeType() == From;166 167    return false;168  }169 170  if (To->isMemberFunctionPointerType()) {171    if (!From->isMemberFunctionPointerType())172      return false;173 174    const auto *FromMember = cast<MemberPointerType>(From);175    const auto *ToMember = cast<MemberPointerType>(To);176 177    // Note: converting Derived::* to Base::* is a different kind of conversion,178    // called Pointer-to-member conversion.179    return FromMember->getQualifier() == ToMember->getQualifier() &&180           FromMember->getMostRecentCXXRecordDecl() ==181               ToMember->getMostRecentCXXRecordDecl() &&182           FromMember->getPointeeType() == ToMember->getPointeeType();183  }184 185  return false;186}187 188// Checks if From is qualification convertible to To based on the current189// LangOpts. If From is any array, we perform the array to pointer conversion190// first. The function only performs checks based on C++ rules, which can differ191// from the C rules.192//193// The function should only be called in C++ mode.194static bool isQualificationConvertiblePointer(QualType From, QualType To,195                                              const LangOptions &LangOpts) {196  // [N4659 7.5 (1)]197  // A cv-decomposition of a type T is a sequence of cv_i and P_i such that T is198  //    cv_0 P_0 cv_1 P_1 ... cv_n−1 P_n−1 cv_n U” for n > 0,199  // where each cv_i is a set of cv-qualifiers, and each P_i is “pointer to”,200  // “pointer to member of class C_i of type”, “array of N_i”, or201  // “array of unknown bound of”.202  //203  // If P_i designates an array, the cv-qualifiers cv_i+1 on the element type204  // are also taken as the cv-qualifiers cvi of the array.205  //206  // The n-tuple of cv-qualifiers after the first one in the longest207  // cv-decomposition of T, that is, cv_1, cv_2, ... , cv_n, is called the208  // cv-qualification signature of T.209 210  // NOLINTNEXTLINE (readability-identifier-naming): Preserve original notation211  auto IsValidP_i = [](QualType P) {212    return P->isPointerType() || P->isMemberPointerType() ||213           P->isConstantArrayType() || P->isIncompleteArrayType();214  };215 216  // NOLINTNEXTLINE (readability-identifier-naming): Preserve original notation217  auto IsSameP_i = [](QualType P1, QualType P2) {218    if (P1->isPointerType())219      return P2->isPointerType();220 221    if (P1->isMemberPointerType())222      return P2->isMemberPointerType() &&223             P1->getAs<MemberPointerType>()->getMostRecentCXXRecordDecl() ==224                 P2->getAs<MemberPointerType>()->getMostRecentCXXRecordDecl();225 226    if (P1->isConstantArrayType())227      return P2->isConstantArrayType() &&228             cast<ConstantArrayType>(P1)->getSize() ==229                 cast<ConstantArrayType>(P2)->getSize();230 231    if (P1->isIncompleteArrayType())232      return P2->isIncompleteArrayType();233 234    return false;235  };236 237  // (2)238  // Two types From and To are similar if they have cv-decompositions with the239  // same n such that corresponding P_i components are the same [(added by240  // N4849 7.3.5) or one is “array of N_i” and the other is “array of unknown241  // bound of”], and the types denoted by U are the same.242  //243  // (3)244  // A prvalue expression of type From can be converted to type To if the245  // following conditions are satisfied:246  //  - From and To are similar247  //  - For every i > 0, if const is in cv_i of From then const is in cv_i of248  //  To, and similarly for volatile.249  //  - [(derived from addition by N4849 7.3.5) If P_i of From is “array of250  //  unknown bound of”, P_i of To is “array of unknown bound of”.]251  //  - If the cv_i of From and cv_i of To are different, then const is in every252  //  cv_k of To for 0 < k < i.253 254  int I = 0;255  bool ConstUntilI = true;256  auto SatisfiesCVRules = [&I, &ConstUntilI](const QualType &From,257                                             const QualType &To) {258    if (I > 1) {259      if (From.getQualifiers() != To.getQualifiers() && !ConstUntilI)260        return false;261    }262 263    if (I > 0) {264      if (From.isConstQualified() && !To.isConstQualified())265        return false;266 267      if (From.isVolatileQualified() && !To.isVolatileQualified())268        return false;269 270      ConstUntilI = To.isConstQualified();271    }272 273    return true;274  };275 276  while (IsValidP_i(From) && IsValidP_i(To)) {277    // Remove every sugar.278    From = From.getCanonicalType();279    To = To.getCanonicalType();280 281    if (!SatisfiesCVRules(From, To))282      return false;283 284    if (!IsSameP_i(From, To)) {285      if (LangOpts.CPlusPlus20) {286        if (From->isConstantArrayType() && !To->isIncompleteArrayType())287          return false;288 289        if (From->isIncompleteArrayType() && !To->isIncompleteArrayType())290          return false;291 292      } else {293        return false;294      }295    }296 297    ++I;298    std::optional<QualType> FromPointeeOrElem =299        getPointeeOrArrayElementQualType(From);300    std::optional<QualType> ToPointeeOrElem =301        getPointeeOrArrayElementQualType(To);302 303    assert(FromPointeeOrElem &&304           "From pointer or array has no pointee or element!");305    assert(ToPointeeOrElem && "To pointer or array has no pointee or element!");306 307    From = *FromPointeeOrElem;308    To = *ToPointeeOrElem;309  }310 311  // In this case the length (n) of From and To are not the same.312  if (IsValidP_i(From) || IsValidP_i(To))313    return false;314 315  // We hit U.316  if (!SatisfiesCVRules(From, To))317    return false;318 319  return From.getTypePtr() == To.getTypePtr();320}321 322static bool canThrow(const FunctionDecl *Func) {323  // consteval specifies that every call to the function must produce a324  // compile-time constant, which cannot evaluate a throw expression without325  // producing a compilation error.326  if (Func->isConsteval())327    return false;328 329  const auto *FunProto = Func->getType()->getAs<FunctionProtoType>();330  if (!FunProto)331    return true;332 333  switch (FunProto->canThrow()) {334  case CT_Cannot:335    return false;336  case CT_Dependent: {337    const Expr *NoexceptExpr = FunProto->getNoexceptExpr();338    if (!NoexceptExpr)339      return true; // no noexcept - can throw340 341    if (NoexceptExpr->isValueDependent())342      return true; // depend on template - some instance can throw343 344    bool Result = false;345    if (!NoexceptExpr->EvaluateAsBooleanCondition(Result, Func->getASTContext(),346                                                  /*InConstantContext=*/true))347      return true;  // complex X condition in noexcept(X), cannot validate,348                    // assume that may throw349    return !Result; // noexcept(false) - can throw350  }351  default:352    return true;353  };354}355 356ExceptionAnalyzer::ExceptionInfo::Throwables357ExceptionAnalyzer::ExceptionInfo::filterByCatch(const Type *HandlerTy,358                                                const ASTContext &Context) {359  llvm::SmallVector<const Type *, 8> TypesToDelete;360  for (const auto &ThrownException : ThrownExceptions) {361    const Type *ExceptionTy = ThrownException.getFirst();362    const CanQualType ExceptionCanTy =363        ExceptionTy->getCanonicalTypeUnqualified();364    const CanQualType HandlerCanTy = HandlerTy->getCanonicalTypeUnqualified();365 366    // The handler is of type cv T or cv T& and E and T are the same type367    // (ignoring the top-level cv-qualifiers) ...368    if (ExceptionCanTy == HandlerCanTy) {369      TypesToDelete.push_back(ExceptionTy);370    }371 372    // The handler is of type cv T or cv T& and T is an unambiguous public base373    // class of E ...374    else if (isUnambiguousPublicBaseClass(ExceptionCanTy->getTypePtr(),375                                          HandlerCanTy->getTypePtr())) {376      TypesToDelete.push_back(ExceptionTy);377    }378 379    if (HandlerCanTy->getTypeClass() == Type::RValueReference ||380        (HandlerCanTy->getTypeClass() == Type::LValueReference &&381         !HandlerCanTy->getTypePtr()->getPointeeType().isConstQualified()))382      continue;383    // The handler is of type cv T or const T& where T is a pointer or384    // pointer-to-member type and E is a pointer or pointer-to-member type that385    // can be converted to T by one or more of ...386    if (isPointerOrPointerToMember(HandlerCanTy->getTypePtr()) &&387        isPointerOrPointerToMember(ExceptionCanTy->getTypePtr())) {388      // A standard pointer conversion not involving conversions to pointers to389      // private or protected or ambiguous classes ...390      if (isStandardPointerConvertible(ExceptionCanTy, HandlerCanTy)) {391        TypesToDelete.push_back(ExceptionTy);392      }393      // A function pointer conversion ...394      else if (isFunctionPointerConvertible(ExceptionCanTy, HandlerCanTy)) {395        TypesToDelete.push_back(ExceptionTy);396      }397      // A a qualification conversion ...398      else if (isQualificationConvertiblePointer(ExceptionCanTy, HandlerCanTy,399                                                 Context.getLangOpts())) {400        TypesToDelete.push_back(ExceptionTy);401      }402    }403 404    // The handler is of type cv T or const T& where T is a pointer or405    // pointer-to-member type and E is std::nullptr_t.406    else if (isPointerOrPointerToMember(HandlerCanTy->getTypePtr()) &&407             ExceptionCanTy->isNullPtrType()) {408      TypesToDelete.push_back(ExceptionTy);409    }410  }411 412  Throwables DeletedExceptions;413 414  for (const Type *TypeToDelete : TypesToDelete) {415    const auto DeleteIt = ThrownExceptions.find(TypeToDelete);416    if (DeleteIt != ThrownExceptions.end()) {417      DeletedExceptions.insert(*DeleteIt);418      ThrownExceptions.erase(DeleteIt);419    }420  }421 422  reevaluateBehaviour();423  return DeletedExceptions;424}425 426ExceptionAnalyzer::ExceptionInfo &427ExceptionAnalyzer::ExceptionInfo::filterIgnoredExceptions(428    const llvm::StringSet<> &IgnoredTypes, bool IgnoreBadAlloc) {429  llvm::SmallVector<const Type *, 8> TypesToDelete;430  // Note: Using a 'SmallSet' with 'llvm::remove_if()' is not possible.431  // Therefore this slightly hacky implementation is required.432  for (const auto &ThrownException : ThrownExceptions) {433    const Type *T = ThrownException.getFirst();434    if (const auto *TD = T->getAsTagDecl()) {435      if (TD->getDeclName().isIdentifier()) {436        if ((IgnoreBadAlloc &&437             (TD->getName() == "bad_alloc" && TD->isInStdNamespace())) ||438            (IgnoredTypes.contains(TD->getName())))439          TypesToDelete.push_back(T);440      }441    }442  }443  for (const Type *T : TypesToDelete)444    ThrownExceptions.erase(T);445 446  reevaluateBehaviour();447  return *this;448}449 450void ExceptionAnalyzer::ExceptionInfo::clear() {451  Behaviour = State::NotThrowing;452  ContainsUnknown = false;453  ThrownExceptions.clear();454}455 456void ExceptionAnalyzer::ExceptionInfo::reevaluateBehaviour() {457  if (ThrownExceptions.empty())458    if (ContainsUnknown)459      Behaviour = State::Unknown;460    else461      Behaviour = State::NotThrowing;462  else463    Behaviour = State::Throwing;464}465ExceptionAnalyzer::ExceptionInfo ExceptionAnalyzer::throwsException(466    const FunctionDecl *Func, const ExceptionInfo::Throwables &Caught,467    CallStack &CallStack, SourceLocation CallLoc) {468  if (!Func || CallStack.contains(Func) ||469      (!CallStack.empty() && !canThrow(Func)))470    return ExceptionInfo::createNonThrowing();471 472  if (const Stmt *Body = Func->getBody()) {473    CallStack.insert({Func, CallLoc});474    ExceptionInfo Result = throwsException(Body, Caught, CallStack);475 476    // For a constructor, we also have to check the initializers.477    if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(Func)) {478      for (const CXXCtorInitializer *Init : Ctor->inits()) {479        const ExceptionInfo Excs =480            throwsException(Init->getInit(), Caught, CallStack);481        Result.merge(Excs);482      }483    }484 485    CallStack.erase(Func);486    return Result;487  }488 489  auto Result = ExceptionInfo::createUnknown();490  if (const auto *FPT = Func->getType()->getAs<FunctionProtoType>()) {491    for (const QualType &Ex : FPT->exceptions()) {492      CallStack.insert({Func, CallLoc});493      Result.registerException(494          Ex.getTypePtr(),495          {Func->getExceptionSpecSourceRange().getBegin(), CallStack});496      CallStack.erase(Func);497    }498  }499  return Result;500}501 502/// Analyzes a single statement on it's throwing behaviour. This is in principle503/// possible except some 'Unknown' functions are called.504ExceptionAnalyzer::ExceptionInfo505ExceptionAnalyzer::throwsException(const Stmt *St,506                                   const ExceptionInfo::Throwables &Caught,507                                   CallStack &CallStack) {508  auto Results = ExceptionInfo::createNonThrowing();509  if (!St)510    return Results;511 512  if (const auto *Throw = dyn_cast<CXXThrowExpr>(St)) {513    if (const auto *ThrownExpr = Throw->getSubExpr()) {514      const auto *ThrownType =515          ThrownExpr->getType()->getUnqualifiedDesugaredType();516      if (ThrownType->isReferenceType())517        ThrownType = ThrownType->castAs<ReferenceType>()518                         ->getPointeeType()519                         ->getUnqualifiedDesugaredType();520      Results.registerException(521          ThrownExpr->getType()->getUnqualifiedDesugaredType(),522          {Throw->getBeginLoc(), CallStack});523    } else524      // A rethrow of a caught exception happens which makes it possible525      // to throw all exception that are caught in the 'catch' clause of526      // the parent try-catch block.527      Results.registerExceptions(Caught);528  } else if (const auto *Try = dyn_cast<CXXTryStmt>(St)) {529    ExceptionInfo Uncaught =530        throwsException(Try->getTryBlock(), Caught, CallStack);531    for (unsigned I = 0; I < Try->getNumHandlers(); ++I) {532      const CXXCatchStmt *Catch = Try->getHandler(I);533 534      // Everything is caught through 'catch(...)'.535      if (!Catch->getExceptionDecl()) {536        const ExceptionInfo Rethrown = throwsException(537            Catch->getHandlerBlock(), Uncaught.getExceptions(), CallStack);538        Results.merge(Rethrown);539        Uncaught.clear();540      } else {541        const auto *CaughtType =542            Catch->getCaughtType()->getUnqualifiedDesugaredType();543        if (CaughtType->isReferenceType()) {544          CaughtType = CaughtType->castAs<ReferenceType>()545                           ->getPointeeType()546                           ->getUnqualifiedDesugaredType();547        }548 549        // If the caught exception will catch multiple previously potential550        // thrown types (because it's sensitive to inheritance) the throwing551        // situation changes. First of all filter the exception types and552        // analyze if the baseclass-exception is rethrown.553        const ExceptionInfo::Throwables FilteredExceptions =554            Uncaught.filterByCatch(CaughtType,555                                   Catch->getExceptionDecl()->getASTContext());556        if (!FilteredExceptions.empty()) {557          const ExceptionInfo Rethrown = throwsException(558              Catch->getHandlerBlock(), FilteredExceptions, CallStack);559          Results.merge(Rethrown);560        }561      }562    }563    Results.merge(Uncaught);564  } else if (const auto *DefaultInit = dyn_cast<CXXDefaultInitExpr>(St)) {565    const ExceptionInfo Excs =566        throwsException(DefaultInit->getExpr(), Caught, CallStack);567    Results.merge(Excs);568  } else if (const auto *Coro = dyn_cast<CoroutineBodyStmt>(St)) {569    for (const Stmt *Child : Coro->childrenExclBody()) {570      if (Child != Coro->getExceptionHandler()) {571        const ExceptionInfo Excs = throwsException(Child, Caught, CallStack);572        Results.merge(Excs);573      }574    }575    const ExceptionInfo Excs =576        throwsException(Coro->getBody(), Caught, CallStack);577    Results.merge(throwsException(Coro->getExceptionHandler(),578                                  Excs.getExceptions(), CallStack));579    for (const auto &Exception : Excs.getExceptions()) {580      const Type *ExcType = Exception.getFirst();581      if (const CXXRecordDecl *ThrowableRec = ExcType->getAsCXXRecordDecl()) {582        const ExceptionInfo DestructorExcs = throwsException(583            ThrowableRec->getDestructor(), Caught, CallStack, SourceLocation{});584        Results.merge(DestructorExcs);585      }586    }587  } else if (const auto *Lambda = dyn_cast<LambdaExpr>(St)) {588    for (const Stmt *Init : Lambda->capture_inits()) {589      const ExceptionInfo Excs = throwsException(Init, Caught, CallStack);590      Results.merge(Excs);591    }592  } else {593    // Check whether any of this node's subexpressions throws.594    for (const Stmt *Child : St->children()) {595      const ExceptionInfo Excs = throwsException(Child, Caught, CallStack);596      Results.merge(Excs);597    }598 599    // If this node is a call to a function or constructor, also check600    // whether the call itself throws.601    if (const auto *Call = dyn_cast<CallExpr>(St)) {602      if (const FunctionDecl *Func = Call->getDirectCallee()) {603        const ExceptionInfo Excs =604            throwsException(Func, Caught, CallStack, Call->getBeginLoc());605        Results.merge(Excs);606      }607    } else if (const auto *Construct = dyn_cast<CXXConstructExpr>(St)) {608      const ExceptionInfo Excs =609          throwsException(Construct->getConstructor(), Caught, CallStack,610                          Construct->getBeginLoc());611      Results.merge(Excs);612    }613  }614  return Results;615}616 617ExceptionAnalyzer::ExceptionInfo618ExceptionAnalyzer::analyzeImpl(const FunctionDecl *Func) {619  ExceptionInfo ExceptionList;620 621  // Check if the function has already been analyzed and reuse that result.622  const auto CacheEntry = FunctionCache.find(Func);623  if (CacheEntry == FunctionCache.end()) {624    CallStack CallStack;625    ExceptionList = throwsException(Func, ExceptionInfo::Throwables(),626                                    CallStack, Func->getLocation());627 628    // Cache the result of the analysis. This is done prior to filtering629    // because it is best to keep as much information as possible.630    // The results here might be relevant to different analysis passes631    // with different needs as well.632    FunctionCache.try_emplace(Func, ExceptionList);633  } else634    ExceptionList = CacheEntry->getSecond();635 636  return ExceptionList;637}638 639ExceptionAnalyzer::ExceptionInfo640ExceptionAnalyzer::analyzeImpl(const Stmt *Stmt) {641  CallStack CallStack;642  return throwsException(Stmt, ExceptionInfo::Throwables(), CallStack);643}644 645template <typename T>646ExceptionAnalyzer::ExceptionInfo647ExceptionAnalyzer::analyzeDispatch(const T *Node) {648  ExceptionInfo ExceptionList = analyzeImpl(Node);649 650  if (ExceptionList.getBehaviour() == State::NotThrowing ||651      ExceptionList.getBehaviour() == State::Unknown)652    return ExceptionList;653 654  // Remove all ignored exceptions from the list of exceptions that can be655  // thrown.656  ExceptionList.filterIgnoredExceptions(IgnoredExceptions, IgnoreBadAlloc);657 658  return ExceptionList;659}660 661ExceptionAnalyzer::ExceptionInfo662ExceptionAnalyzer::analyze(const FunctionDecl *Func) {663  return analyzeDispatch(Func);664}665 666ExceptionAnalyzer::ExceptionInfo ExceptionAnalyzer::analyze(const Stmt *Stmt) {667  return analyzeDispatch(Stmt);668}669 670} // namespace clang::tidy::utils671