[libc++] Build and test with -Wundef warning. NFC.

This will avoid typos like `_LIBCPP_STD_VERS` (<future>) or using `#if TEST_STD_VER > 17` without including "test_macros.h".

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D99515

libcxx/CMakeLists.txt

@@ -583,7 +583,7 @@ function(cxx_add_warning_flags target)
   endif()
   target_add_compile_flags_if_supported(${target} PRIVATE -Wextra -W -Wwrite-strings
                                                           -Wno-unused-parameter -Wno-long-long
-                                                          -Werror=return-type -Wextra-semi)
+                                                          -Werror=return-type -Wextra-semi -Wundef)
   if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
     target_add_compile_flags_if_supported(${target} PRIVATE
       -Wno-user-defined-literals

libcxx/include/__config

@@ -183,11 +183,12 @@
 #define __has_include(...) 0
 #endif
 
-#if defined(__clang__)
+#if defined(__apple_build_version__)
-#  define _LIBCPP_COMPILER_CLANG
+#  define _LIBCPP_COMPILER_CLANG_BASED
-#  ifndef __apple_build_version__
+#  define _LIBCPP_APPLE_CLANG_VER (__apple_build_version__ / 10000)
-#    define _LIBCPP_CLANG_VER (__clang_major__ * 100 + __clang_minor__)
+#elif defined(__clang__)
-#  endif
+#  define _LIBCPP_COMPILER_CLANG_BASED
+#  define _LIBCPP_CLANG_VER (__clang_major__ * 100 + __clang_minor__)
 #elif defined(__GNUC__)
 #  define _LIBCPP_COMPILER_GCC
 #elif defined(_MSC_VER)
@@ -350,7 +351,7 @@
 #  define _LIBCPP_NO_CFI
 #endif
 
-#if __ISO_C_VISIBLE >= 2011 || __cplusplus >= 201103L
+#if (defined(__ISO_C_VISIBLE) && (__ISO_C_VISIBLE >= 2011)) || __cplusplus >= 201103L
 #  if defined(__FreeBSD__)
 #    define _LIBCPP_HAS_ALIGNED_ALLOC
 #    define _LIBCPP_HAS_QUICK_EXIT
@@ -404,7 +405,7 @@
 
 #ifndef _LIBCPP_CXX03_LANG
 # define _LIBCPP_ALIGNOF(_Tp) alignof(_Tp)
-#elif defined(_LIBCPP_COMPILER_CLANG)
+#elif defined(_LIBCPP_COMPILER_CLANG_BASED)
 # define _LIBCPP_ALIGNOF(_Tp) _Alignof(_Tp)
 #else
 # error "We don't know a correct way to implement alignof(T) in C++03 outside of Clang"
@@ -412,7 +413,7 @@
 
 #define _LIBCPP_PREFERRED_ALIGNOF(_Tp) __alignof(_Tp)
 
-#if defined(_LIBCPP_COMPILER_CLANG)
+#if defined(_LIBCPP_COMPILER_CLANG_BASED)
 
 #if defined(_LIBCPP_ALTERNATE_STRING_LAYOUT)
 #  error _LIBCPP_ALTERNATE_STRING_LAYOUT is deprecated, please use _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT instead
@@ -510,8 +511,8 @@ typedef __char32_t char32_t;
 #define _LIBCPP_ALWAYS_INLINE __attribute__ ((__always_inline__))
 
 // Literal operators ""d and ""y are supported starting with LLVM Clang 8 and AppleClang 10.0.1
-#if (defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 800) || \
+#if (defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 800) ||                 \
-    (defined(__apple_build_version__) && __apple_build_version__ < 10010000)
+    (defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1001)
 #define _LIBCPP_HAS_NO_CXX20_CHRONO_LITERALS
 #endif
 
@@ -1028,8 +1029,8 @@ typedef unsigned int   char32_t;
 #endif
 
 // Macros to enter and leave a state where deprecation warnings are suppressed.
-#if !defined(_LIBCPP_SUPPRESS_DEPRECATED_PUSH) && \
+#if !defined(_LIBCPP_SUPPRESS_DEPRECATED_PUSH) &&                              \
-    (defined(_LIBCPP_COMPILER_CLANG) || defined(_LIBCPP_COMPILER_GCC))
+    (defined(_LIBCPP_COMPILER_CLANG_BASED) || defined(_LIBCPP_COMPILER_GCC))
 #  define _LIBCPP_SUPPRESS_DEPRECATED_PUSH \
     _Pragma("GCC diagnostic push") \
     _Pragma("GCC diagnostic ignored \"-Wdeprecated\"")
@@ -1069,7 +1070,7 @@ typedef unsigned int   char32_t;
 // NODISCARD macros to the correct attribute.
 #if __has_cpp_attribute(nodiscard) || defined(_LIBCPP_COMPILER_MSVC)
 #  define _LIBCPP_NODISCARD_ATTRIBUTE [[nodiscard]]
-#elif defined(_LIBCPP_COMPILER_CLANG) && !defined(_LIBCPP_CXX03_LANG)
+#elif defined(_LIBCPP_COMPILER_CLANG_BASED) && !defined(_LIBCPP_CXX03_LANG)
 #  define _LIBCPP_NODISCARD_ATTRIBUTE [[clang::warn_unused_result]]
 #else
 // We can't use GCC's [[gnu::warn_unused_result]] and
@@ -1119,7 +1120,7 @@ extern "C" _LIBCPP_FUNC_VIS void __sanitizer_annotate_contiguous_container(
 #endif
 
 // Try to find out if RTTI is disabled.
-#if defined(_LIBCPP_COMPILER_CLANG) && !__has_feature(cxx_rtti)
+#if defined(_LIBCPP_COMPILER_CLANG_BASED) && !__has_feature(cxx_rtti)
 #  define _LIBCPP_NO_RTTI
 #elif defined(__GNUC__) && !defined(__GXX_RTTI)
 #  define _LIBCPP_NO_RTTI

libcxx/include/experimental/simd

@@ -725,12 +725,12 @@ constexpr size_t __ceil_pow_of_2(size_t __val) {
 
 template <class _Tp, size_t __bytes>
 struct __vec_ext_traits {
-#if !defined(_LIBCPP_COMPILER_CLANG)
+#if !defined(_LIBCPP_COMPILER_CLANG_BASED)
   typedef _Tp type __attribute__((vector_size(__ceil_pow_of_2(__bytes))));
 #endif
 };
 
-#if defined(_LIBCPP_COMPILER_CLANG)
+#if defined(_LIBCPP_COMPILER_CLANG_BASED)
 #define _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, _NUM_ELEMENT)                        \
   template <>                                                                  \
   struct __vec_ext_traits<_TYPE, sizeof(_TYPE) * _NUM_ELEMENT> {               \

libcxx/include/ext/hash_map

@@ -208,7 +208,7 @@ template <class Key, class T, class Hash, class Pred, class Alloc>
 #include <type_traits>
 #include <ext/__hash>
 
-#if __DEPRECATED
+#if defined(__DEPRECATED) && __DEPRECATED
 #if defined(_LIBCPP_WARNING)
     _LIBCPP_WARNING("Use of the header <ext/hash_map> is deprecated.  Migrate to <unordered_map>")
 #else

libcxx/include/ext/hash_set

@@ -197,7 +197,7 @@ template <class Value, class Hash, class Pred, class Alloc>
 #include <functional>
 #include <ext/__hash>
 
-#if __DEPRECATED
+#if defined(__DEPRECATED) && __DEPRECATED
 #if defined(_LIBCPP_WARNING)
     _LIBCPP_WARNING("Use of the header <ext/hash_set> is deprecated.  Migrate to <unordered_set>")
 #else

libcxx/include/future

@@ -501,9 +501,7 @@ class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_FUTURE_ERROR future_error
     error_code __ec_;
 public:
     future_error(error_code __ec);
-#if _LIBCPP_STD_VERS > 14
+
-    explicit future_error(future_errc _Ev) : logic_error(), __ec_(make_error_code(_Ev)) {}
-#endif
     _LIBCPP_INLINE_VISIBILITY
     const error_code& code() const _NOEXCEPT {return __ec_;}
 

libcxx/include/type_traits

@@ -834,8 +834,10 @@ _LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_array_v
 
 // is_pointer
 
-// Before Clang 11, __is_pointer didn't work for Objective-C types.
+// Before Clang 11 / AppleClang 12.0.5, __is_pointer didn't work for Objective-C types.
-#if __has_keyword(__is_pointer) && !(defined(_LIBCPP_COMPILER_CLANG) && _LIBCPP_CLANG_VER < 1100)
+#if __has_keyword(__is_pointer) &&                                             \
+    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1100) &&               \
+    !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1205)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
@@ -1131,7 +1133,9 @@ _LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_arithmetic_v
 
 // Before Clang 10, __is_fundamental didn't work for nullptr_t.
 // In C++03 nullptr_t is library-provided but must still count as "fundamental."
-#if __has_keyword(__is_fundamental) && !(defined(_LIBCPP_COMPILER_CLANG) && _LIBCPP_CLANG_VER < 1000) && !defined(_LIBCPP_CXX03_LANG)
+#if __has_keyword(__is_fundamental) &&                                         \
+    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000) &&               \
+    !defined(_LIBCPP_CXX03_LANG)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
@@ -1416,7 +1420,8 @@ template<class _Tp> using type_identity_t = typename type_identity<_Tp>::type;
 // is_signed
 
 // Before Clang 10, __is_signed didn't work for floating-point types or enums.
-#if __has_keyword(__is_signed) && !(defined(_LIBCPP_COMPILER_CLANG) && _LIBCPP_CLANG_VER < 1000)
+#if __has_keyword(__is_signed) &&                                              \
+    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
@@ -1452,7 +1457,10 @@ _LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR bool is_signed_v
 // is_unsigned
 
 // Before Clang 13, __is_unsigned returned true for enums with signed underlying type.
-#if __has_keyword(__is_unsigned) && !(defined(_LIBCPP_COMPILER_CLANG) && _LIBCPP_CLANG_VER < 1300)
+// No currently-released version of AppleClang contains the fixed intrinsic.
+#if __has_keyword(__is_unsigned) &&                                            \
+    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1300) &&               \
+    !defined(_LIBCPP_APPLE_CLANG_VER)
 
 template<class _Tp>
 struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };

libcxx/test/std/atomics/types.pass.cpp

@@ -24,12 +24,13 @@
 
 #include <thread>
 #include <chrono>
+
+#include "test_macros.h"
+
 #if TEST_STD_VER >= 20
 # include <memory>
 #endif
 
-#include "test_macros.h"
-
 template <class A, bool Integral>
 struct test_atomic
 {

libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq_all_zero.pass.cpp

@@ -25,11 +25,8 @@
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
-#if TEST_STD_VER >= 11
-#include <initializer_list>
 
 #include "test_macros.h"
-#endif
 
 struct all_zero_seed_seq {
   typedef unsigned int result_type;

libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp

@@ -19,11 +19,11 @@
 #include <memory>
 #include <cassert>
 
+#include "test_macros.h"
+
 #if TEST_STD_VER >= 11
 #include "poisoned_hash_helper.h"
 
-#include "test_macros.h"
-
 struct A {};
 #endif
 

libcxx/test/support/test_macros.h

@@ -165,7 +165,8 @@
 
 // Sniff out to see if the underlying C library has C11 features
 // This is cribbed from __config; but lives here as well because we can't assume libc++
-#if __ISO_C_VISIBLE >= 2011 || TEST_STD_VER >= 11
+#if (defined(__ISO_C_VISIBLE) && (__ISO_C_VISIBLE >= 2011)) ||                 \
+    TEST_STD_VER >= 11
 #  if defined(__FreeBSD__)
 #    if __FreeBSD_version >= 1300064 || \
        (__FreeBSD_version >= 1201504 && __FreeBSD_version < 1300000)

libcxx/utils/libcxx/test/params.py

@@ -14,6 +14,7 @@ _warningFlags = [
   '-Wall',
   '-Wextra',
   '-Wshadow',
+  '-Wundef',
   '-Wno-unused-command-line-argument',
   '-Wno-attributes',
   '-Wno-pessimizing-move',