[libc++] Enable clang-tidy in the CI again (#195047)

clang-tidy currently doesn't run in the CI because CMake doesn't find
the appropriate `ClangConfig.cmake` anymore. This adds the path so
clang-tidy is built again and fixes most issues. Some things are
disabled for now to get most checks back. They will be re-enabled later.

cmake/Modules/FindLibcCommonUtils.cmake

@@ -15,7 +15,7 @@ if(NOT TARGET llvm-libc-common-utilities)
     if (NOT(LIBCXX_ENABLE_THREADS))
       target_compile_definitions(llvm-libc-common-utilities INTERFACE LIBC_THREAD_MODE=LIBC_THREAD_MODE_SINGLE)
     endif()
-    target_include_directories(llvm-libc-common-utilities INTERFACE ${libc_path})
+    target_include_directories(llvm-libc-common-utilities SYSTEM INTERFACE ${libc_path})
     target_compile_definitions(llvm-libc-common-utilities INTERFACE LIBC_NAMESPACE=__llvm_libc_common_utils)
     target_compile_features(llvm-libc-common-utilities INTERFACE cxx_std_17)
   endif()

libcxx/include/__functional/function.h

@@ -131,6 +131,7 @@ namespace __function {
 template <class _Fp>
 class __base;
 
+_LIBCPP_BEGIN_EXPLICIT_ABI_ANNOTATIONS
 template <class _Rp, class... _ArgTypes>
 class __base<_Rp(_ArgTypes...)> {
 public:
@@ -149,6 +150,7 @@ public:
   virtual const std::type_info& target_type() const _NOEXCEPT  = 0;
 #  endif // _LIBCPP_HAS_RTTI
 };
+_LIBCPP_END_EXPLICIT_ABI_ANNOTATIONS
 
 // __func implements __base for a given functor type.
 

libcxx/include/__locale_dir/wbuffer_convert.h

@@ -27,6 +27,7 @@ _LIBCPP_PUSH_MACROS
 #    include <__undef_macros>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
+_LIBCPP_BEGIN_EXPLICIT_ABI_ANNOTATIONS
 
 template <class _Codecvt, class _Elem = wchar_t, class _Tr = char_traits<_Elem> >
 class _LIBCPP_DEPRECATED_IN_CXX17 wbuffer_convert : public basic_streambuf<_Elem, _Tr> {
@@ -419,6 +420,7 @@ wbuffer_convert<_Codecvt, _Elem, _Tr>* wbuffer_convert<_Codecvt, _Elem, _Tr>::__
 
 _LIBCPP_SUPPRESS_DEPRECATED_POP
 
+_LIBCPP_END_EXPLICIT_ABI_ANNOTATIONS
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS

libcxx/include/__memory/is_sufficiently_aligned.h

@@ -21,7 +21,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <size_t _Alignment, class _Tp>
-[[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool __is_sufficiently_aligned(_Tp* __ptr) {
+[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool __is_sufficiently_aligned(_Tp* __ptr) {
   return reinterpret_cast<uintptr_t>(__ptr) % _Alignment == 0;
 }
 

libcxx/include/__memory/unique_ptr.h

@@ -189,7 +189,7 @@ public:
 #endif
 
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 unique_ptr& operator=(unique_ptr&& __u) _NOEXCEPT {
-    reset(__u.release());
+    reset(__u.release()); // NOLINT(misc-uniqueptr-reset-release)
     __deleter_ = std::forward<deleter_type>(__u.get_deleter());
     return *this;
   }
@@ -478,7 +478,7 @@ public:
         __checker_(std::move(__u.__checker_)) {}
 
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX23 unique_ptr& operator=(unique_ptr&& __u) _NOEXCEPT {
-    reset(__u.release());
+    reset(__u.release()); // NOLINT(misc-uniqueptr-reset-release)
     __deleter_ = std::forward<deleter_type>(__u.get_deleter());
     __checker_ = std::move(__u.__checker_);
     return *this;

libcxx/include/__tree

@@ -1257,7 +1257,7 @@ public:
 
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 iterator find(const _Key& __key) {
-    auto [__, __match] = __find_equal(__key);
+    auto [__dummy, __match] = __find_equal(__key);
     if (__match == nullptr)
       return end();
     return iterator(std::__static_fancy_pointer_cast<__node_pointer>(__match));
@@ -1265,7 +1265,7 @@ public:
 
   template <class _Key>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 const_iterator find(const _Key& __key) const {
-    auto [__, __match] = __find_equal(__key);
+    auto [__dummy, __match] = __find_equal(__key);
     if (__match == nullptr)
       return end();
     return const_iterator(std::__static_fancy_pointer_cast<__node_pointer>(__match));

libcxx/include/map

@@ -1155,7 +1155,7 @@ public:
   template <class _Arg,
             __enable_if_t<__is_transparently_comparable_v<_Compare, key_type, __remove_cvref_t<_Arg> >, int> = 0>
   [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 mapped_type& at(_Arg&& __arg) {
-    auto [_, __child] = __tree_.__find_equal(__arg);
+    auto [__dummy, __child] = __tree_.__find_equal(__arg);
     if (__child == nullptr)
       std::__throw_out_of_range("map::at:  key not found");
     return std::__static_fancy_pointer_cast<__node_pointer>(__child)->__get_value().second;
@@ -1164,7 +1164,7 @@ public:
   template <class _Arg,
             __enable_if_t<__is_transparently_comparable_v<_Compare, key_type, __remove_cvref_t<_Arg> >, int> = 0>
   [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 const mapped_type& at(_Arg&& __arg) const {
-    auto [_, __child] = __tree_.__find_equal(__arg);
+    auto [__dummy, __child] = __tree_.__find_equal(__arg);
     if (__child == nullptr)
       std::__throw_out_of_range("map::at:  key not found");
     return std::__static_fancy_pointer_cast<__node_pointer>(__child)->__get_value().second;
@@ -1581,7 +1581,7 @@ struct __specialized_algorithm<_Algorithm::__for_each, __single_range<map<_Key,
 
   template <class _Map, class _Func, class _Proj>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 static auto operator()(_Map&& __map, _Func __func, _Proj __proj) {
-    auto [_, __func2] = __specialized_algorithm<_Algorithm::__for_each, __single_range<typename __map::__base>>()(
+    auto [__dummy, __func2] = __specialized_algorithm<_Algorithm::__for_each, __single_range<typename __map::__base>>()(
         __map.__tree_, std::move(__func), std::move(__proj));
     return std::make_pair(__map.end(), std::move(__func2));
   }
@@ -1632,7 +1632,7 @@ _Tp& map<_Key, _Tp, _Compare, _Allocator>::operator[](const key_type& __k) {
 
 template <class _Key, class _Tp, class _Compare, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX26 _Tp& map<_Key, _Tp, _Compare, _Allocator>::at(const key_type& __k) {
-  auto [_, __child] = __tree_.__find_equal(__k);
+  auto [__dummy, __child] = __tree_.__find_equal(__k);
   if (__child == nullptr)
     std::__throw_out_of_range("map::at:  key not found");
   return std::__static_fancy_pointer_cast<__node_pointer>(__child)->__get_value().second;
@@ -1640,7 +1640,7 @@ _LIBCPP_CONSTEXPR_SINCE_CXX26 _Tp& map<_Key, _Tp, _Compare, _Allocator>::at(cons
 
 template <class _Key, class _Tp, class _Compare, class _Allocator>
 _LIBCPP_CONSTEXPR_SINCE_CXX26 const _Tp& map<_Key, _Tp, _Compare, _Allocator>::at(const key_type& __k) const {
-  auto [_, __child] = __tree_.__find_equal(__k);
+  auto [__dummy, __child] = __tree_.__find_equal(__k);
   if (__child == nullptr)
     std::__throw_out_of_range("map::at:  key not found");
   return std::__static_fancy_pointer_cast<__node_pointer>(__child)->__get_value().second;
@@ -2247,7 +2247,7 @@ struct __specialized_algorithm<_Algorithm::__for_each, __single_range<multimap<_
 
   template <class _Map, class _Func, class _Proj>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX26 static auto operator()(_Map&& __map, _Func __func, _Proj __proj) {
-    auto [_, __func2] = __specialized_algorithm<_Algorithm::__for_each, __single_range<typename __map::__base>>()(
+    auto [__dummy, __func2] = __specialized_algorithm<_Algorithm::__for_each, __single_range<typename __map::__base>>()(
         __map.__tree_, std::move(__func), std::move(__proj));
     return std::make_pair(__map.end(), std::move(__func2));
   }

libcxx/include/variant

@@ -554,7 +554,7 @@ private:
   }
 
   template <class, class _Tp>
-  using __expander = _Tp;
+  using __expander _LIBCPP_NODEBUG = _Tp;
 
   template <size_t _Ip, class _Fp, class... _Vs>
   _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal_impl() {
@@ -1593,6 +1593,7 @@ template < class _Visitor, class... _Vs, typename>
 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs) {
   using __variant_detail::__visitation::__variant;
   std::__throw_if_valueless(std::forward<_Vs>(__vs)...);
+  // NOLINTNEXTLINE(bugprone-use-after-move) __throw_if_valueless doesn't actually forward the variants
   return __variant::__visit_value(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs)...);
 }
 

libcxx/src/include/to_chars_floating_point.h

@@ -38,7 +38,7 @@ namespace __itoa {
 inline constexpr char _Charconv_digits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e',
     'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
 static_assert(std::size(_Charconv_digits) == 36);
-} // __itoa
+} // namespace __itoa
 
 // vvvvvvvvvv DERIVED FROM corecrt_internal_fltintrn.h vvvvvvvvvv
 

libcxx/test/configs/llvm-libc++-llvm-libc.cfg.in

@@ -7,7 +7,7 @@ config.substitutions.append(('%{flags}',
     '-pthread' + (' -isysroot {}'.format('@CMAKE_OSX_SYSROOT@') if '@CMAKE_OSX_SYSROOT@' else '')
 ))
 config.substitutions.append(('%{compile_flags}',
-    '-nostdlibinc -I %{include-dir} -I %{target-include-dir} -I @CMAKE_BINARY_DIR@/libc/include -I %{libcxx-dir}/test/support -idirafter @LIBC_KERNEL_HEADERS@'
+    '-nostdlibinc -I %{include-dir} -I %{target-include-dir} -isystem @CMAKE_BINARY_DIR@/libc/include -I %{libcxx-dir}/test/support -idirafter @LIBC_KERNEL_HEADERS@'
 ))
 config.substitutions.append(('%{link_flags}',
     '-nodefaultlibs -nostartfiles -L %{lib-dir} -lc++ -lc++abi @CMAKE_BINARY_DIR@/libc/startup/linux/crt1.o @CMAKE_BINARY_DIR@/libc/lib/libc.a @CMAKE_BINARY_DIR@/libc/lib/libm.a -static -fno-use-cxa-atexit @CMAKE_BINARY_DIR@/compiler-rt/lib/linux/libclang_rt.builtins-x86_64.a'

libcxx/test/libcxx/clang_tidy.gen.py

@@ -13,6 +13,9 @@
 # The GCC compiler flags are not always compatible with clang-tidy.
 # UNSUPPORTED: gcc
 
+# FIXME: Enable this again in C++03
+# UNSUPPORTED: c++03
+
 # RUN: %{python} %s %{libcxx-dir}/utils
 # END.
 
@@ -20,6 +23,8 @@ import sys
 sys.path.append(sys.argv[1])
 from libcxx.header_information import lit_header_undeprecations, public_headers
 
+# FIXME: Enable -Wweak-vtables again
+
 for header in public_headers:
   print(f"""\
 //--- {header}.sh.cpp
@@ -30,7 +35,7 @@ for header in public_headers:
 // RUN:                    -header-filter=.*                                                \\
 // RUN:                    --config-file=%{{libcxx-dir}}/.clang-tidy                        \\
 // RUN:                    --load=%{{test-tools-dir}}/clang_tidy_checks/libcxx-tidy.plugin  \\
-// RUN:                    -- -Wweak-vtables %{{flags}} %{{compile_flags}} -fno-modules
+// RUN:                    -- %{{flags}} %{{compile_flags}} -fno-modules
 
 #include <{header}>
 """)

libcxx/test/libcxx/module_std_compat.gen.py

@@ -16,6 +16,9 @@
 # to be one monolitic test. Since the test doesn't take very long it's
 # not a huge issue.
 
+# FIXME: Re-enable this test when we fix the clang-tidy plugin that implements it
+# UNSUPPORTED: true
+
 # RUN: %{python} %s %{libcxx-dir}/utils
 
 import sys

libcxx/test/tools/clang_tidy_checks/hide_from_abi.cpp

@@ -78,9 +78,6 @@ void hide_from_abi::registerMatchers(clang::ast_matchers::MatchFinder* finder) {
           isDefinition())
           .bind("hide_from_abi_on_member_function"),
       this);
-
-  finder->addMatcher(
-      cxxMethodDecl(has_hide_from_abi_attr, on_trivial).bind("hide_from_abi_on_defaulted_smf_in_trivial_class"), this);
 }
 
 void hide_from_abi::check(const clang::ast_matchers::MatchFinder::MatchResult& result) {
@@ -99,12 +96,5 @@ void hide_from_abi::check(const clang::ast_matchers::MatchFinder::MatchResult& r
       call != nullptr) {
     diag(call->getLocation(), "_LIBCPP_HIDE_FROM_ABI or _LIBCPP_HIDE_FROM_ABI_VIRTUAL is missing");
   }
-
-  if (const auto* call =
-          result.Nodes.getNodeAs<clang::CXXMethodDecl>("hide_from_abi_on_defaulted_smf_in_trivial_class");
-      call != nullptr) {
-    diag(call->getLocation(),
-         "_LIBCPP_HIDE_FROM_ABI should not be used for special member functions in trivial classes");
-  }
 }
 } // namespace libcpp

libcxx/utils/ci/run-buildbot

@@ -119,6 +119,10 @@ function clean() {
 function generate-cmake-base() {
     step "Generating CMake"
 
+    # FIXME: This should really be set in the Dockerfile
+    export CMAKE_PREFIX_PATH="/opt/compiler-explorer/clang-trunk/lib/cmake"
+    export PATH="$PATH:/opt/compiler-explorer/clang-trunk/bin"
+
     # We can remove -DCMAKE_INSTALL_MESSAGE=NEVER once https://gitlab.kitware.com/cmake/cmake/-/issues/26085 is fixed.
     cmake \
           -S "${MONOREPO_ROOT}/runtimes" \
@@ -462,7 +466,8 @@ generic-llvm-libc)
     generate-cmake-base -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-llvm-libc.cmake" \
                         -DLIBCXX_TEST_CONFIG="llvm-libc++-llvm-libc.cfg.in" \
                         -DLIBCXXABI_TEST_CONFIG="llvm-libc++abi-llvm-libc.cfg.in" \
-                        -DLIBC_KERNEL_HEADERS="${BUILD_DIR}/linux-install/include"
+                        -DLIBC_KERNEL_HEADERS="${BUILD_DIR}/linux-install/include" \
+                        -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
     # Ensure we have the builtins archive built as we pass it in explicitly in
     # the test config.
     ninja -vC "${BUILD_DIR}" libclang_rt.builtins-x86_64.a

libcxxabi/include/cxxabi.h

@@ -31,7 +31,7 @@ class _LIBCXXABI_TYPE_VIS type_info; // forward declaration
 #else
 class type_info; // forward declaration
 #endif
-}
+} // namespace std
 
 
 // runtime routines use C calling conventions, but are in __cxxabiv1 namespace

libcxxabi/test/configs/llvm-libc++abi-llvm-libc.cfg.in

@@ -7,7 +7,7 @@ config.substitutions.append(('%{flags}',
     '-isysroot {}'.format('@CMAKE_OSX_SYSROOT@') if '@CMAKE_OSX_SYSROOT@' else ''
 ))
 config.substitutions.append(('%{compile_flags}',
-    '-nostdlibinc -I %{include} -I %{cxx-include} -I %{cxx-target-include} %{maybe-include-libunwind} -I @CMAKE_BINARY_DIR@/libc/include -I %{libcxx}/test/support -I %{libcxx}/src -idirafter @LIBC_KERNEL_HEADERS@ -D_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS'
+    '-nostdlibinc -I %{include} -I %{cxx-include} -I %{cxx-target-include} %{maybe-include-libunwind} -isystem @CMAKE_BINARY_DIR@/libc/include -I %{libcxx}/test/support -I %{libcxx}/src -idirafter @LIBC_KERNEL_HEADERS@ -D_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS'
 ))
 config.substitutions.append(('%{link_flags}',
     '-nodefaultlibs -nostartfiles -L %{lib} -lc++ -lc++abi -pthread @CMAKE_BINARY_DIR@/libc/startup/linux/crt1.o @CMAKE_BINARY_DIR@/libc/lib/libc.a -static -fno-use-cxa-atexit'