1 files changed, 124 insertions, 0 deletions
diff --git a/intern/cycles/device/cpu/kernel_function.h b/intern/cycles/device/cpu/kernel_function.h
new file mode 100644
index 00000000000..aa18720cc24
--- /dev/null
+++ b/intern/cycles/device/cpu/kernel_function.h
@@ -0,0 +1,124 @@
+/*
+ * Copyright 2011-2021 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "util/util_debug.h"
+#include "util/util_system.h"
+
+CCL_NAMESPACE_BEGIN
+
+/* A wrapper around per-microarchitecture variant of a kernel function.
+ *
+ * Provides a function-call-like API which gets routed to the most suitable implementation.
+ *
+ * For example, on a computer which only has SSE4.1 the kernel_sse41 will be used. */
+template<typename FunctionType> class CPUKernelFunction {
+ public:
+  CPUKernelFunction(FunctionType kernel_default,
+                    FunctionType kernel_sse2,
+                    FunctionType kernel_sse3,
+                    FunctionType kernel_sse41,
+                    FunctionType kernel_avx,
+                    FunctionType kernel_avx2)
+  {
+    kernel_info_ = get_best_kernel_info(
+        kernel_default, kernel_sse2, kernel_sse3, kernel_sse41, kernel_avx, kernel_avx2);
+  }
+
+  template<typename... Args> inline auto operator()(Args... args) const
+  {
+    assert(kernel_info_.kernel);
+
+    return kernel_info_.kernel(args...);
+  }
+
+  const char *get_uarch_name() const
+  {
+    return kernel_info_.uarch_name;
+  }
+
+ protected:
+  /* Helper class which allows to pass human-readable microarchitecture name together with function
+   * pointer. */
+  class KernelInfo {
+   public:
+    KernelInfo() : KernelInfo("", nullptr)
+    {
+    }
+
+    /* TODO(sergey): Use string view, to have higher-level functionality (i.e. comparison) without
+     * memory allocation. */
+    KernelInfo(const char *uarch_name, FunctionType kernel)
+        : uarch_name(uarch_name), kernel(kernel)
+    {
+    }
+
+    const char *uarch_name;
+    FunctionType kernel;
+  };
+
+  KernelInfo get_best_kernel_info(FunctionType kernel_default,
+                                  FunctionType kernel_sse2,
+                                  FunctionType kernel_sse3,
+                                  FunctionType kernel_sse41,
+                                  FunctionType kernel_avx,
+                                  FunctionType kernel_avx2)
+  {
+    /* Silence warnings about unused variables when compiling without some architectures. */
+    (void)kernel_sse2;
+    (void)kernel_sse3;
+    (void)kernel_sse41;
+    (void)kernel_avx;
+    (void)kernel_avx2;
+
+#ifdef WITH_CYCLES_OPTIMIZED_KERNEL_AVX2
+    if (DebugFlags().cpu.has_avx2() && system_cpu_support_avx2()) {
+      return KernelInfo("AVX2", kernel_avx2);
+    }
+#endif
+
+#ifdef WITH_CYCLES_OPTIMIZED_KERNEL_AVX
+    if (DebugFlags().cpu.has_avx() && system_cpu_support_avx()) {
+      return KernelInfo("AVX", kernel_avx);
+    }
+#endif
+
+#ifdef WITH_CYCLES_OPTIMIZED_KERNEL_SSE41
+    if (DebugFlags().cpu.has_sse41() && system_cpu_support_sse41()) {
+      return KernelInfo("SSE4.1", kernel_sse41);
+    }
+#endif
+
+#ifdef WITH_CYCLES_OPTIMIZED_KERNEL_SSE3
+    if (DebugFlags().cpu.has_sse3() && system_cpu_support_sse3()) {
+      return KernelInfo("SSE3", kernel_sse3);
+    }
+#endif
+
+#ifdef WITH_CYCLES_OPTIMIZED_KERNEL_SSE2
+    if (DebugFlags().cpu.has_sse2() && system_cpu_support_sse2()) {
+      return KernelInfo("SSE2", kernel_sse2);
+    }
+#endif
+
+    return KernelInfo("default", kernel_default);
+  }
+
+  KernelInfo kernel_info_;
+};
+
+CCL_NAMESPACE_END