| //===----------------------------------------------------------------------===// |
| // |
| // 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 "clang-tidy/ClangTidyCheck.h" |
| #include "clang-tidy/ClangTidyModuleRegistry.h" |
| |
| #include "abi_tag_on_virtual.hpp" |
| |
| // This clang-tidy check ensures that we don't place an abi_tag attribute on |
| // virtual functions. This can happen by mistakenly applying a macro like |
| // _LIBCPP_HIDE_FROM_ABI on a virtual function. |
| // |
| // The problem is that arm64e pointer authentication extensions use the mangled |
| // name of the function to sign the function pointer in the vtable, which means |
| // that the ABI tag effectively influences how the pointers are signed. |
| // |
| // This can lead to PAC failures when passing an object that holds one of these |
| // pointers in its vtable across an ABI boundary if the two sides have been compiled |
| // with different versions of libc++: one side will sign the pointer using one function |
| // mangling (with one ABI tag), and the other side will authenticate the pointer expecting |
| // it to have a different mangled name due to the ABI tag being different, which will crash. |
| // |
| // This test ensures that we don't re-introduce this issue in the code base. |
| |
| namespace libcpp { |
| abi_tag_on_virtual::abi_tag_on_virtual(llvm::StringRef name, clang::tidy::ClangTidyContext* context) |
| : clang::tidy::ClangTidyCheck(name, context) {} |
| |
| void abi_tag_on_virtual::registerMatchers(clang::ast_matchers::MatchFinder* finder) { |
| using namespace clang::ast_matchers; |
| finder->addMatcher(cxxMethodDecl(isVirtual(), hasAttr(clang::attr::AbiTag)).bind("abi_tag_on_virtual"), this); |
| } |
| |
| void abi_tag_on_virtual::check(const clang::ast_matchers::MatchFinder::MatchResult& result) { |
| if (const auto* call = result.Nodes.getNodeAs<clang::CXXMethodDecl>("abi_tag_on_virtual"); call != nullptr) { |
| diag(call->getBeginLoc(), |
| "_LIBCPP_HIDE_FROM_ABI should not be used on virtual functions to avoid problems with pointer authentication. " |
| "Use _LIBCPP_HIDE_FROM_ABI_VIRTUAL instead."); |
| } |
| } |
| } // namespace libcpp |