1 //===--- UnhandledExceptionAtNewCheck.cpp - clang-tidy --------------------===//
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 #include "UnhandledExceptionAtNewCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 
13 using namespace clang::ast_matchers;
14 
15 namespace clang {
16 namespace tidy {
17 namespace bugprone {
18 
19 AST_MATCHER_P(CXXTryStmt, hasHandlerFor,
20               ast_matchers::internal::Matcher<QualType>, InnerMatcher) {
21   for (unsigned NH = Node.getNumHandlers(), I = 0; I < NH; ++I) {
22     const CXXCatchStmt *CatchS = Node.getHandler(I);
23     // Check for generic catch handler (match anything).
24     if (CatchS->getCaughtType().isNull())
25       return true;
26     ast_matchers::internal::BoundNodesTreeBuilder Result(*Builder);
27     if (InnerMatcher.matches(CatchS->getCaughtType(), Finder, &Result)) {
28       *Builder = std::move(Result);
29       return true;
30     }
31   }
32   return false;
33 }
34 
35 AST_MATCHER(CXXNewExpr, mayThrow) {
36   FunctionDecl *OperatorNew = Node.getOperatorNew();
37   if (!OperatorNew)
38     return false;
39   return !OperatorNew->getType()->castAs<FunctionProtoType>()->isNothrow();
40 }
41 
42 UnhandledExceptionAtNewCheck::UnhandledExceptionAtNewCheck(
43     StringRef Name, ClangTidyContext *Context)
44     : ClangTidyCheck(Name, Context) {}
45 
46 void UnhandledExceptionAtNewCheck::registerMatchers(MatchFinder *Finder) {
47   auto BadAllocType =
48       recordType(hasDeclaration(cxxRecordDecl(hasName("::std::bad_alloc"))));
49   auto ExceptionType =
50       recordType(hasDeclaration(cxxRecordDecl(hasName("::std::exception"))));
51   auto BadAllocReferenceType = referenceType(pointee(BadAllocType));
52   auto ExceptionReferenceType = referenceType(pointee(ExceptionType));
53 
54   auto CatchBadAllocType =
55       qualType(hasCanonicalType(anyOf(BadAllocType, BadAllocReferenceType,
56                                       ExceptionType, ExceptionReferenceType)));
57   auto BadAllocCatchingTryBlock = cxxTryStmt(hasHandlerFor(CatchBadAllocType));
58 
59   auto FunctionMayNotThrow = functionDecl(isNoThrow());
60 
61   Finder->addMatcher(cxxNewExpr(mayThrow(),
62                                 unless(hasAncestor(BadAllocCatchingTryBlock)),
63                                 hasAncestor(FunctionMayNotThrow))
64                          .bind("new-expr"),
65                      this);
66 }
67 
68 void UnhandledExceptionAtNewCheck::check(
69     const MatchFinder::MatchResult &Result) {
70   const auto *MatchedExpr = Result.Nodes.getNodeAs<CXXNewExpr>("new-expr");
71   if (MatchedExpr)
72     diag(MatchedExpr->getBeginLoc(),
73          "missing exception handler for allocation failure at 'new'");
74 }
75 
76 } // namespace bugprone
77 } // namespace tidy
78 } // namespace clang
79