Use _xgetbv intrinsic on Windows for AVX2 detection.

The intrinsic is supported since VS2010 SP1, which is below our minimum supported MSVC version. The intrinsic is the proper way to detect support for AVX register state by the OS instead of the undocumented GetEnabledExtendedFeatures WinAPI function.
boostorg · Apr 13, 2024 · 38bf38e · 38bf38e
1 parent 2d932dd
commit 38bf38e
Showing 1 changed file with 3 additions and 14 deletions.
diff --git a/src/dump.cpp b/src/dump.cpp
@@ -18,8 +18,8 @@
 #include <boost/cstdint.hpp>
 #include <boost/log/utility/manipulators/dump.hpp>
 #if defined(_MSC_VER) && (defined(BOOST_LOG_USE_SSSE3) || defined(BOOST_LOG_USE_AVX2))
-#include <boost/winapi/dll.hpp>
 #include <intrin.h> // __cpuid
+#include <immintrin.h> // _xgetbv
 #endif
 #include <boost/log/detail/header.hpp>
 
@@ -180,19 +180,8 @@ struct function_pointer_initializer
                             : "c" (0)
                     );
                     mmstate = (eax & 6u) == 6u;
-#elif defined(BOOST_WINDOWS)
-                    // MSVC does not have an intrinsic for xgetbv, we have to query OS
-                    boost::winapi::HMODULE_ hKernel32 = boost::winapi::GetModuleHandleW(L"kernel32.dll");
-                    if (hKernel32)
-                    {
-                        typedef uint64_t (BOOST_WINAPI_WINAPI_CC* get_enabled_extended_features_t)(uint64_t);
-                        get_enabled_extended_features_t get_enabled_extended_features = (get_enabled_extended_features_t)boost::winapi::get_proc_address(hKernel32, "GetEnabledExtendedFeatures");
-                        if (get_enabled_extended_features)
-                        {
-                            // XSTATE_MASK_LEGACY_SSE | XSTATE_MASK_GSSE == 6
-                            mmstate = get_enabled_extended_features(6u) == 6u;
-                        }
-                    }
+#elif defined(_MSC_VER)
+                    mmstate = (_xgetbv(_XCR_XFEATURE_ENABLED_MASK) & 6u) == 6u;
 #endif
 
                     if (mmstate)