ac,radeonsi: move some VS input descriptions to ac_shader_abi

v2: use LLVM values instead of function parameter indices

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/amd/common/ac_shader_abi.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2017 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, and/or sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHOR(S) AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef AC_SHADER_ABI_H
+#define AC_SHADER_ABI_H
+
+#include <llvm-c/Core.h>
+
+/* Document the shader ABI during compilation. This is what allows radeonsi and
+ * radv to share a compiler backend.
+ */
+struct ac_shader_abi {
+	LLVMValueRef base_vertex;
+	LLVMValueRef start_instance;
+	LLVMValueRef draw_id;
+	LLVMValueRef vertex_id;
+	LLVMValueRef instance_id;
+};
+
+#endif /* AC_SHADER_ABI_H */