| //===--- MultipleNewInOneExpressionCheck.cpp - clang-tidy------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "MultipleNewInOneExpressionCheck.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/ASTMatchers/ASTMatchFinder.h" |
| #include "clang/Lex/Lexer.h" |
| |
| using namespace clang::ast_matchers; |
| using namespace clang; |
| |
| namespace { |
| |
| // Determine if the result of an expression is "stored" in some way. |
| // It is true if the value is stored into a variable or used as initialization |
| // or passed to a function or constructor. |
| // For this use case compound assignments are not counted as a "store" (the 'E' |
| // expression should have pointer type). |
| bool isExprValueStored(const Expr *E, ASTContext &C) { |
| E = E->IgnoreParenCasts(); |
| // Get first non-paren, non-cast parent. |
| ParentMapContext &PMap = C.getParentMapContext(); |
| DynTypedNodeList P = PMap.getParents(*E); |
| if (P.size() != 1) |
| return false; |
| const Expr *ParentE; |
| while ((ParentE = P[0].get<Expr>()) && ParentE->IgnoreParenCasts() == E) { |
| P = PMap.getParents(P[0]); |
| if (P.size() != 1) |
| return false; |
| } |
| |
| if (const auto *ParentVarD = P[0].get<VarDecl>()) |
| return ParentVarD->getInit()->IgnoreParenCasts() == E; |
| |
| if (!ParentE) |
| return false; |
| |
| if (const auto *BinOp = dyn_cast<BinaryOperator>(ParentE)) |
| return BinOp->getOpcode() == BO_Assign && |
| BinOp->getRHS()->IgnoreParenCasts() == E; |
| |
| return isa<CallExpr, CXXConstructExpr>(ParentE); |
| } |
| |
| } // namespace |
| |
| namespace clang { |
| namespace tidy { |
| namespace bugprone { |
| |
| AST_MATCHER_P(CXXTryStmt, hasHandlerFor, |
| ast_matchers::internal::Matcher<QualType>, InnerMatcher) { |
| for (unsigned NH = Node.getNumHandlers(), I = 0; I < NH; ++I) { |
| const CXXCatchStmt *CatchS = Node.getHandler(I); |
| // Check for generic catch handler (match anything). |
| if (CatchS->getCaughtType().isNull()) |
| return true; |
| ast_matchers::internal::BoundNodesTreeBuilder Result(*Builder); |
| if (InnerMatcher.matches(CatchS->getCaughtType(), Finder, &Result)) { |
| *Builder = std::move(Result); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| AST_MATCHER(CXXNewExpr, mayThrow) { |
| FunctionDecl *OperatorNew = Node.getOperatorNew(); |
| if (!OperatorNew) |
| return false; |
| return !OperatorNew->getType()->castAs<FunctionProtoType>()->isNothrow(); |
| } |
| |
| void MultipleNewInOneExpressionCheck::registerMatchers(MatchFinder *Finder) { |
| auto BadAllocType = |
| recordType(hasDeclaration(cxxRecordDecl(hasName("::std::bad_alloc")))); |
| auto ExceptionType = |
| recordType(hasDeclaration(cxxRecordDecl(hasName("::std::exception")))); |
| auto BadAllocReferenceType = referenceType(pointee(BadAllocType)); |
| auto ExceptionReferenceType = referenceType(pointee(ExceptionType)); |
| |
| auto CatchBadAllocType = |
| qualType(hasCanonicalType(anyOf(BadAllocType, BadAllocReferenceType, |
| ExceptionType, ExceptionReferenceType))); |
| auto BadAllocCatchingTryBlock = cxxTryStmt(hasHandlerFor(CatchBadAllocType)); |
| |
| auto NewExprMayThrow = cxxNewExpr(mayThrow()); |
| auto HasNewExpr1 = expr(anyOf(NewExprMayThrow.bind("new1"), |
| hasDescendant(NewExprMayThrow.bind("new1")))); |
| auto HasNewExpr2 = expr(anyOf(NewExprMayThrow.bind("new2"), |
| hasDescendant(NewExprMayThrow.bind("new2")))); |
| |
| Finder->addMatcher( |
| callExpr( |
| hasAnyArgument( |
| expr(HasNewExpr1).bind("arg1")), |
| hasAnyArgument( |
| expr(HasNewExpr2, unless(equalsBoundNode("arg1"))).bind("arg2")), |
| hasAncestor(BadAllocCatchingTryBlock)), |
| this); |
| Finder->addMatcher( |
| cxxConstructExpr( |
| hasAnyArgument( |
| expr(HasNewExpr1).bind("arg1")), |
| hasAnyArgument( |
| expr(HasNewExpr2, unless(equalsBoundNode("arg1"))).bind("arg2")), |
| unless(isListInitialization()), |
| hasAncestor(BadAllocCatchingTryBlock)), |
| this); |
| Finder->addMatcher(binaryOperator(hasLHS(HasNewExpr1), hasRHS(HasNewExpr2), |
| unless(hasAnyOperatorName("&&", "||", ",")), |
| hasAncestor(BadAllocCatchingTryBlock)), |
| this); |
| Finder->addMatcher( |
| cxxNewExpr(mayThrow(), |
| hasDescendant(NewExprMayThrow.bind("new2_in_new1")), |
| hasAncestor(BadAllocCatchingTryBlock)) |
| .bind("new1"), |
| this); |
| } |
| |
| void MultipleNewInOneExpressionCheck::check( |
| const MatchFinder::MatchResult &Result) { |
| const auto *NewExpr1 = Result.Nodes.getNodeAs<CXXNewExpr>("new1"); |
| const auto *NewExpr2 = Result.Nodes.getNodeAs<CXXNewExpr>("new2"); |
| const auto *NewExpr2InNewExpr1 = |
| Result.Nodes.getNodeAs<CXXNewExpr>("new2_in_new1"); |
| if (!NewExpr2) |
| NewExpr2 = NewExpr2InNewExpr1; |
| assert(NewExpr1 && NewExpr2 && "Bound nodes not found."); |
| |
| // No warning if both allocations are not stored. |
| // The value may be intentionally not stored (no deallocations needed or |
| // self-destructing object). |
| if (!isExprValueStored(NewExpr1, *Result.Context) && |
| !isExprValueStored(NewExpr2, *Result.Context)) |
| return; |
| |
| // In C++17 sequencing of a 'new' inside constructor arguments of another |
| // 'new' is fixed. Still a leak can happen if the returned value from the |
| // first 'new' is not saved (yet) and the second fails. |
| if (getLangOpts().CPlusPlus17 && NewExpr2InNewExpr1) |
| diag(NewExpr1->getBeginLoc(), |
| "memory allocation may leak if an other allocation is sequenced after " |
| "it and throws an exception") |
| << NewExpr1->getSourceRange() << NewExpr2->getSourceRange(); |
| else |
| diag(NewExpr1->getBeginLoc(), |
| "memory allocation may leak if an other allocation is sequenced after " |
| "it and throws an exception; order of these allocations is undefined") |
| << NewExpr1->getSourceRange() << NewExpr2->getSourceRange(); |
| } |
| |
| } // namespace bugprone |
| } // namespace tidy |
| } // namespace clang |