aaron.ballman created this revision.
aaron.ballman added reviewers: alexfh, sbenza.
aaron.ballman added a subscriber: cfe-commits.
This patch adds a new clang-tidy checker that flags throw expressions whose
thrown type is not nothrow copy constructible. While the compiler is free to
elide copy constructor calls in some cases, it is under no obligation to do so,
which makes the code a portability concern as well as a security concern.
This checker corresponds to the CERT secure coding rule:
https://www.securecoding.cert.org/confluence/display/cplusplus/ERR60-CPP.+Exception+objects+must+be+nothrow+copy+constructible
http://reviews.llvm.org/D14619
Files:
clang-tidy/cert/CERTTidyModule.cpp
clang-tidy/cert/CMakeLists.txt
clang-tidy/cert/ThrownExceptionTypeCheck.cpp
clang-tidy/cert/ThrownExceptionTypeCheck.h
docs/clang-tidy/checks/cert-thrown-exception-type.rst
docs/clang-tidy/checks/list.rst
test/clang-tidy/cert-throw-exception-type.cpp
Index: test/clang-tidy/cert-throw-exception-type.cpp
===================================================================
--- test/clang-tidy/cert-throw-exception-type.cpp
+++ test/clang-tidy/cert-throw-exception-type.cpp
@@ -0,0 +1,90 @@
+// RUN: %check_clang_tidy %s cert-err60-cpp %t -- -- -std=c++11 -fcxx-exceptions
+
+struct S {};
+struct T : S {};
+struct U {
+ U() = default;
+ U(const U&) = default;
+};
+
+struct V {
+ V() = default;
+ V(const V&) noexcept;
+};
+
+struct W {
+ W() = default;
+ W(const W&) noexcept(false);
+};
+
+struct X {
+ X() = default;
+ X(const X&) {}
+};
+
+struct Y {
+ Y() = default;
+ Y(const Y&) throw();
+};
+
+struct Z {
+ Z() = default;
+ Z(const Z&) throw(int);
+};
+
+void g() noexcept(false);
+
+struct A {
+ A() = default;
+ A(const A&) noexcept(noexcept(g()));
+};
+
+struct B {
+ B() = default;
+ B(const B&) = default;
+ B(const A&) noexcept(false);
+};
+
+class C {
+ W M; // W is not no-throw copy constructible
+public:
+ C() = default;
+ C(const C&) = default;
+};
+
+struct D {
+ D() = default;
+ D(const D&) noexcept(false);
+ D(D&) noexcept(true);
+};
+
+struct E {
+ E() = default;
+ E(E&) noexcept(true);
+ E(const E&) noexcept(false);
+};
+
+void f() {
+ throw 12; // ok
+ throw "test"; // ok
+ throw S(); // ok
+ throw T(); // ok
+ throw U(); // ok
+ throw V(); // ok
+ throw W(); // match, noexcept(false)
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: thrown exception type is not nothrow copy constructible [cert-err60-cpp]
+ throw X(); // match, no noexcept clause, nontrivial
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: thrown exception type is not nothrow copy constructible
+ throw Y(); // ok
+ throw Z(); // match, throw(int)
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: thrown exception type is not nothrow copy constructible
+ throw A(); // match, noexcept(false)
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: thrown exception type is not nothrow copy constructible
+ throw B(); // ok
+ throw C(); // match, C has a member variable that makes it throwing on copy
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: thrown exception type is not nothrow copy constructible
+ throw D();
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: thrown exception type is not nothrow copy constructible
+ throw E();
+ // CHECK-MESSAGES: :[[@LINE-1]]:9: warning: thrown exception type is not nothrow copy constructible
+}
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -3,6 +3,7 @@
.. toctree::
cert-setlongjmp
+ cert-thrown-exception-type
cert-variadic-function-def
cppcoreguidelines-pro-bounds-array-to-pointer-decay
cppcoreguidelines-pro-bounds-pointer-arithmetic
Index: docs/clang-tidy/checks/cert-thrown-exception-type.rst
===================================================================
--- docs/clang-tidy/checks/cert-thrown-exception-type.rst
+++ docs/clang-tidy/checks/cert-thrown-exception-type.rst
@@ -0,0 +1,9 @@
+cert-err60-cpp
+==============
+
+This check flags all throw expressions where the exception object is not nothrow
+copy constructible.
+
+This check corresponds to the CERT C++ Coding Standard rule
+`ERR60-CPP. Exception objects must be nothrow copy constructible
+<https://www.securecoding.cert.org/confluence/display/cplusplus/ERR60-CPP.+Exception+objects+must+be+nothrow+copy+constructible>`_.
Index: clang-tidy/cert/ThrownExceptionTypeCheck.h
===================================================================
--- clang-tidy/cert/ThrownExceptionTypeCheck.h
+++ clang-tidy/cert/ThrownExceptionTypeCheck.h
@@ -0,0 +1,34 @@
+//===--- ThrownExceptionTypeCheck.h - clang-tidy-----------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_THROWNEXCEPTIONTYPECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_THROWNEXCEPTIONTYPECHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+
+/// Checks whether a thrown object is nothrow copy constructible.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/cert-thrown-exception-type.html
+class ThrownExceptionTypeCheck : public ClangTidyCheck {
+public:
+ ThrownExceptionTypeCheck(StringRef Name, ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context) {}
+ void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CERT_THROWNEXCEPTIONTYPECHECK_H
+
Index: clang-tidy/cert/ThrownExceptionTypeCheck.cpp
===================================================================
--- clang-tidy/cert/ThrownExceptionTypeCheck.cpp
+++ clang-tidy/cert/ThrownExceptionTypeCheck.cpp
@@ -0,0 +1,62 @@
+//===--- ThrownExceptionTypeCheck.cpp - clang-tidy-------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ThrownExceptionTypeCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+
+void ThrownExceptionTypeCheck::registerMatchers(MatchFinder *Finder) {
+ if (!getLangOpts().CPlusPlus)
+ return;
+
+ Finder->addMatcher(
+ cxxThrowExpr(
+ has(expr(hasType(cxxRecordDecl().bind("record"))).bind("expr"))),
+ this);
+}
+
+void ThrownExceptionTypeCheck::check(const MatchFinder::MatchResult &Result) {
+ const auto *RD = Result.Nodes.getNodeAs<CXXRecordDecl>("record");
+
+ if (!RD->hasNonTrivialCopyConstructor())
+ return;
+
+ bool Diag = false;
+ for (const auto *Ctor : RD->ctors()) {
+ if (Ctor->isCopyConstructor()) {
+ if (const auto *FnTy = Ctor->getType()->getAs<FunctionProtoType>()) {
+ Diag = !FnTy->isNothrow(*Result.Context);
+ // If any of the copy constructors is throwing, we will assume that it
+ // is plausible that the constructor may be selected by the throw and
+ // diagnose. TODO: we could work a lot harder to only consider the
+ // copy constructor selected by the throw expression and diagnose only
+ // if that one is nonthrowing. However, the FP rate from this is likely
+ // to be quite low.
+ if (Diag)
+ break;
+ }
+ }
+ }
+
+ if (!Diag)
+ return;
+
+ const auto *E = Result.Nodes.getNodeAs<Expr>("expr");
+ diag(E->getExprLoc(),
+ "thrown exception type is not nothrow copy constructible");
+}
+
+} // namespace tidy
+} // namespace clang
+
Index: clang-tidy/cert/CMakeLists.txt
===================================================================
--- clang-tidy/cert/CMakeLists.txt
+++ clang-tidy/cert/CMakeLists.txt
@@ -3,6 +3,7 @@
add_clang_library(clangTidyCERTModule
CERTTidyModule.cpp
SetLongJmpCheck.cpp
+ ThrownExceptionTypeCheck.cpp
VariadicFunctionDefCheck.cpp
LINK_LIBS
Index: clang-tidy/cert/CERTTidyModule.cpp
===================================================================
--- clang-tidy/cert/CERTTidyModule.cpp
+++ clang-tidy/cert/CERTTidyModule.cpp
@@ -17,6 +17,7 @@
#include "../misc/StaticAssertCheck.h"
#include "../misc/ThrowByValueCatchByReferenceCheck.h"
#include "SetLongJmpCheck.h"
+#include "ThrownExceptionTypeCheck.h"
#include "VariadicFunctionDefCheck.h"
namespace clang {
@@ -40,6 +41,8 @@
// ERR
CheckFactories.registerCheck<SetLongJmpCheck>(
"cert-err52-cpp");
+ CheckFactories.registerCheck<ThrownExceptionTypeCheck>(
+ "cert-err60-cpp");
CheckFactories.registerCheck<ThrowByValueCatchByReferenceCheck>(
"cert-err61-cpp");
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