Author: ericwf Date: Mon Aug 29 15:43:38 2016 New Revision: 280007 URL: http://llvm.org/viewvc/llvm-project?rev=280007&view=rev Log: Fix or suppress GCC warnings during build.
Summary: Currently a number of GCC warnings are emitted when building libc++. This patch fixes or ignores all of them. The primary changes are: * Work around strict aliasing issues in `typeinfo::hash_code()` by using __attribute__((may_alias)). However I think a non-aliasing `hash_code()` implementation is possible. Further investigation needed. * Add `_LIBCPP_UNREACHABLE()` to switch in `strstream.cpp` to avoid -Wpotentially-uninitialized. * Fix -Wunused-value warning in `__all` by adding a void cast. * Ignore -Wattributes for now. There are a number of real attribute issues when using GCC but enabling the warning is too noisy. * Ignore -Wliteral-suffix since it warns about the use of reserved identifiers. Note Only GCC 7.0 supports disabling this warning. * Ignore -Wc++14-compat since it warns about the sized new/delete overloads. Reviewers: EricWF Differential Revision: https://reviews.llvm.org/D24003 Modified: libcxx/trunk/CMakeLists.txt libcxx/trunk/include/__config libcxx/trunk/include/__tuple libcxx/trunk/include/cstdlib libcxx/trunk/include/typeinfo libcxx/trunk/src/strstream.cpp Modified: libcxx/trunk/CMakeLists.txt URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/CMakeLists.txt?rev=280007&r1=280006&r2=280007&view=diff ============================================================================== --- libcxx/trunk/CMakeLists.txt (original) +++ libcxx/trunk/CMakeLists.txt Mon Aug 29 15:43:38 2016 @@ -322,10 +322,19 @@ add_compile_flags_if_supported(-nostdinc # Warning flags =============================================================== add_definitions(-D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) add_compile_flags_if_supported( - -Wall -W -Wwrite-strings - -Wno-unused-parameter -Wno-long-long -Wno-user-defined-literals - -Wno-covered-switch-default + -Wall -Wextra -W -Wwrite-strings + -Wno-unused-parameter -Wno-long-long -Werror=return-type) +if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang") + add_compile_flags_if_supported( + -Wno-user-defined-literals + -Wno-covered-switch-default) +elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU") + add_compile_flags_if_supported( + -Wno-attributes # FIXME: Fix -Wattribute warnings. + -Wno-literal-suffix + -Wno-c++14-compat) +endif() if (LIBCXX_ENABLE_WERROR) add_compile_flags_if_supported(-Werror) add_compile_flags_if_supported(-WX) Modified: libcxx/trunk/include/__config URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__config?rev=280007&r1=280006&r2=280007&view=diff ============================================================================== --- libcxx/trunk/include/__config (original) +++ libcxx/trunk/include/__config Mon Aug 29 15:43:38 2016 @@ -691,6 +691,12 @@ template <unsigned> struct __static_asse #define _NOALIAS #endif +#ifdef __GNUC__ +#define _LIBCPP_MAY_ALIAS __attribute__((__may_alias__)) +#else +#define _LIBCPP_MAY_ALIAS +#endif + #if __has_feature(cxx_explicit_conversions) || defined(__IBMCPP__) # define _LIBCPP_EXPLICIT explicit #else Modified: libcxx/trunk/include/__tuple URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__tuple?rev=280007&r1=280006&r2=280007&view=diff ============================================================================== --- libcxx/trunk/include/__tuple (original) +++ libcxx/trunk/include/__tuple Mon Aug 29 15:43:38 2016 @@ -374,7 +374,7 @@ template <bool ..._Preds> struct __all_dummy; template <bool ..._Pred> -using __all = is_same<__all_dummy<_Pred...>, __all_dummy<(_Pred, true)...>>; +using __all = is_same<__all_dummy<_Pred...>, __all_dummy<((void)_Pred, true)...>>; struct __tuple_sfinae_base { template <template <class, class...> class _Trait, Modified: libcxx/trunk/include/cstdlib URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/cstdlib?rev=280007&r1=280006&r2=280007&view=diff ============================================================================== --- libcxx/trunk/include/cstdlib (original) +++ libcxx/trunk/include/cstdlib Mon Aug 29 15:43:38 2016 @@ -89,6 +89,12 @@ void *aligned_alloc(size_t alignment, si #pragma GCC system_header #endif +#ifdef __GNUC__ +#define _LIBCPP_UNREACHABLE() __builtin_unreachable() +#else +#define _LIBCPP_UNREACHABLE() _VSTD::abort() +#endif + _LIBCPP_BEGIN_NAMESPACE_STD using ::size_t; Modified: libcxx/trunk/include/typeinfo URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/typeinfo?rev=280007&r1=280006&r2=280007&view=diff ============================================================================== --- libcxx/trunk/include/typeinfo (original) +++ libcxx/trunk/include/typeinfo Mon Aug 29 15:43:38 2016 @@ -73,6 +73,9 @@ class _LIBCPP_EXCEPTION_ABI type_info { type_info& operator=(const type_info&); type_info(const type_info&); + + typedef size_t _LIBCPP_MAY_ALIAS _ASizeT; // Avoid strict-aliasing issues. + protected: #ifndef _LIBCPP_NONUNIQUE_RTTI_BIT const char* __type_name; @@ -113,7 +116,7 @@ public: _LIBCPP_INLINE_VISIBILITY size_t hash_code() const _NOEXCEPT #ifndef _LIBCPP_NONUNIQUE_RTTI_BIT - {return *reinterpret_cast<const size_t*>(&__type_name);} + {return *reinterpret_cast<const _ASizeT *>(&__type_name);} #else {if (!(__type_name & _LIBCPP_NONUNIQUE_RTTI_BIT)) return __type_name; const char *__ptr = name(); Modified: libcxx/trunk/src/strstream.cpp URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/strstream.cpp?rev=280007&r1=280006&r2=280007&view=diff ============================================================================== --- libcxx/trunk/src/strstream.cpp (original) +++ libcxx/trunk/src/strstream.cpp Mon Aug 29 15:43:38 2016 @@ -11,6 +11,7 @@ #include "algorithm" #include "climits" #include "cstring" +#include "cstdlib" #include "__debug" _LIBCPP_BEGIN_NAMESPACE_STD @@ -266,6 +267,8 @@ strstreambuf::seekoff(off_type __off, io case ios::end: newoff = seekhigh - eback(); break; + default: + _LIBCPP_UNREACHABLE(); } newoff += __off; if (0 <= newoff && newoff <= seekhigh - eback()) _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
