Add a getauxval backend

Author: AntoinePrv

include/xsimd/config/xsimd_cpu_features_arm.hpp

@@ -13,11 +13,9 @@
 #define XSIMD_CPU_FEATURES_ARM_HPP
 
 #include "./xsimd_config.hpp"
-
-#if XSIMD_TARGET_ARM && XSIMD_HAVE_LINUX_GETAUXVAL
-#include "../utils/bits.hpp"
 #include "./xsimd_getauxval.hpp"
 
+#if XSIMD_TARGET_ARM && XSIMD_HAVE_LINUX_GETAUXVAL
 // HWCAP_XXX masks to use on getauxval results.
 // Header does not exists on all architectures and masks are architecture
 // specific.
@@ -36,7 +34,7 @@ namespace xsimd
      * This is well defined on all architectures.
      * It will always return false on non-ARM architectures.
      */
-    class arm_cpu_features
+    class arm_cpu_features : private linux_hwcap_backend_default
     {
     public:
         arm_cpu_features() noexcept = default;
@@ -78,45 +76,6 @@ namespace xsimd
             return false;
 #endif
         }
-
-    private:
-#if XSIMD_TARGET_ARM && XSIMD_HAVE_LINUX_GETAUXVAL
-        enum class status
-        {
-            hwcap_valid = 0,
-            hwcap2_valid = 1,
-        };
-
-        using status_bitset = utils::uint_bitset<status, std::uint32_t>;
-
-        mutable status_bitset m_status {};
-
-        mutable xsimd::linux_auxval m_hwcap {};
-
-        inline xsimd::linux_auxval const& hwcap() const noexcept
-        {
-            if (!m_status.bit_is_set<status::hwcap_valid>())
-            {
-                m_hwcap = xsimd::linux_auxval::read(AT_HWCAP);
-                m_status.set_bit<status::hwcap_valid>();
-            }
-            return m_hwcap;
-        }
-
-#if XSIMD_TARGET_ARM64
-        mutable xsimd::linux_auxval m_hwcap2 {};
-
-        inline xsimd::linux_auxval const& hwcap2() const noexcept
-        {
-            if (!m_status.bit_is_set<status::hwcap2_valid>())
-            {
-                m_hwcap2 = xsimd::linux_auxval::read(AT_HWCAP2);
-                m_status.set_bit<status::hwcap2_valid>();
-            }
-            return m_hwcap2;
-        }
-#endif
-#endif // XSIMD_TARGET_ARM && XSIMD_HAVE_LINUX_GETAUXVAL
     };
 }
 #endif

include/xsimd/config/xsimd_cpu_features_riscv.hpp

@@ -13,11 +13,9 @@
 #define XSIMD_CPU_FEATURES_RISCV_HPP
 
 #include "./xsimd_config.hpp"
-
-#if XSIMD_TARGET_RISCV && XSIMD_HAVE_LINUX_GETAUXVAL
-#include "../utils/bits.hpp"
 #include "./xsimd_getauxval.hpp"
 
+#if XSIMD_TARGET_RISCV && XSIMD_HAVE_LINUX_GETAUXVAL
 // HWCAP_XXX masks to use on getauxval results.
 // Header does not exists on all architectures and masks are architecture
 // specific.
@@ -26,7 +24,7 @@
 
 namespace xsimd
 {
-    class riscv_cpu_features
+    class riscv_cpu_features : private linux_hwcap_backend_default
     {
     public:
         riscv_cpu_features() noexcept = default;
@@ -44,30 +42,6 @@ namespace xsimd
             return false;
 #endif
         }
-
-    private:
-#if XSIMD_TARGET_RISCV && XSIMD_HAVE_LINUX_GETAUXVAL
-        enum class status
-        {
-            hwcap_valid = 0,
-        };
-
-        using status_bitset = utils::uint_bitset<status, std::uint32_t>;
-
-        mutable status_bitset m_status {};
-
-        mutable xsimd::linux_auxval m_hwcap {};
-
-        inline xsimd::linux_auxval const& hwcap() const noexcept
-        {
-            if (!m_status.bit_is_set<status::hwcap_valid>())
-            {
-                m_hwcap = xsimd::linux_auxval::read(AT_HWCAP);
-                m_status.set_bit<status::hwcap_valid>();
-            }
-            return m_hwcap;
-        }
-#endif
     };
 }
 

include/xsimd/config/xsimd_getauxval.hpp

@@ -12,6 +12,7 @@
 #ifndef XSIMD_GETAUXVAL_HPP
 #define XSIMD_GETAUXVAL_HPP
 
+#include "../utils/bits.hpp"
 #include "./xsimd_config.hpp"
 
 #if XSIMD_HAVE_LINUX_GETAUXVAL
@@ -68,6 +69,41 @@ namespace xsimd
         }
     };
 
+    class linux_hwcap_backend_full
+    {
+    public:
+        inline linux_auxval hwcap() const noexcept;
+
+        inline linux_auxval hwcap2() const noexcept;
+
+    private:
+        enum class status
+        {
+            hwcap_valid = 0,
+            hwcap2_valid = 1,
+        };
+
+        using status_bitset = utils::uint_bitset<status, std::uint32_t>;
+
+        mutable status_bitset m_status {};
+        mutable xsimd::linux_auxval m_hwcap {};
+        mutable xsimd::linux_auxval m_hwcap2 {};
+    };
+
+    class linux_hwcap_backend_noop
+    {
+    public:
+        inline linux_auxval hwcap() const noexcept { return {}; }
+
+        inline linux_auxval hwcap2() const noexcept { return {}; }
+    };
+
+#if XSIMD_HAVE_LINUX_GETAUXVAL
+    using linux_hwcap_backend_default = linux_hwcap_backend_full;
+#else
+    using linux_hwcap_backend_default = linux_hwcap_backend_noop;
+#endif
+
     /********************
      *  Implementation  *
      ********************/
@@ -86,6 +122,30 @@ namespace xsimd
         }
 #endif
     }
+
+    inline linux_auxval linux_hwcap_backend_full::hwcap() const noexcept
+    {
+        if (!m_status.bit_is_set<status::hwcap_valid>())
+        {
+#if XSIMD_HAVE_LINUX_GETAUXVAL
+            m_hwcap = linux_auxval::read(AT_HWCAP);
+#endif
+            m_status.set_bit<status::hwcap_valid>();
+        }
+        return m_hwcap;
+    }
+
+    inline linux_auxval linux_hwcap_backend_full::hwcap2() const noexcept
+    {
+        if (!m_status.bit_is_set<status::hwcap2_valid>())
+        {
+#if XSIMD_HAVE_LINUX_GETAUXVAL
+            m_hwcap2 = linux_auxval::read(AT_HWCAP2);
+#endif
+            m_status.set_bit<status::hwcap2_valid>();
+        }
+        return m_hwcap2;
+    }
 }
 
 #endif