From bf5794b2f084ac894375c4683aa6fd738c821854 Mon Sep 17 00:00:00 2001
From: Changcheng Liu <changcheng.liu@aliyun.com>
Date: Thu, 22 Oct 2020 13:11:05 +0800
Subject: [PATCH] cmake: define cmake macro to check nasm assembler

Signed-off-by: Changcheng Liu <changcheng.liu@aliyun.com>
---
 cmake/modules/CheckNasm.cmake | 58 +++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 cmake/modules/CheckNasm.cmake

diff --git a/cmake/modules/CheckNasm.cmake b/cmake/modules/CheckNasm.cmake
new file mode 100644
index 0000000000000..32e0085c97801
--- /dev/null
+++ b/cmake/modules/CheckNasm.cmake
@@ -0,0 +1,58 @@
+macro(check_nasm_support _object_format _support_x64 _support_x64_and_avx2 _support_x64_and_avx512)
+  execute_process(
+    COMMAND which nasm
+    RESULT_VARIABLE no_nasm
+    OUTPUT_QUIET
+    ERROR_QUIET)
+  if(NOT no_nasm)
+    if(CMAKE_SYSTEM_PROCESSOR MATCHES "amd64|x86_64")
+      set(save_quiet ${CMAKE_REQUIRED_QUIET})
+      set(CMAKE_REQUIRED_QUIET true)
+      include(CheckCXXSourceCompiles)
+      check_cxx_source_compiles("
+      #if defined(__x86_64__) && defined(__ILP32__)
+      #error x32
+      #endif
+      int main() {}
+      " not_arch_x32)
+      set(CMAKE_REQUIRED_QUIET ${save_quiet})
+      if(not_arch_x32)
+        set(${_support_x64} TRUE)
+        execute_process(COMMAND nasm -f ${object_format} -i
+          ${CMAKE_SOURCE_DIR}/src/isa-l/include/
+          ${CMAKE_SOURCE_DIR}/src/isa-l/erasure_code/gf_vect_dot_prod_avx2.asm
+          -o /dev/null
+          RESULT_VARIABLE rc
+          OUTPUT_QUIET
+          ERROR_QUIET)
+        if(NOT rc)
+          set(${_support_x64_and_avx2} TRUE)
+        endif(NOT rc)
+        execute_process(COMMAND nasm -D HAVE_AS_KNOWS_AVX512 -f ${object_format}
+          -i ${CMAKE_SOURCE_DIR}/src/isa-l/include/
+          ${CMAKE_SOURCE_DIR}/src/isa-l/erasure_code/gf_vect_dot_prod_avx512.asm
+          -o /dev/null
+          RESULT_VARIABLE rt
+          OUTPUT_QUIET
+          ERROR_QUIET)
+        if(NOT rt)
+          set(${_support_x64_and_avx512} TRUE)
+        endif(NOT rt)
+      endif(not_arch_x32)
+    endif(CMAKE_SYSTEM_PROCESSOR MATCHES "amd64|x86_64")
+  endif(NOT no_nasm)
+  if(no_nasm)
+    message(STATUS "Could NOT find nasm")
+  elseif(NOT not_arch_x32)
+    message(STATUS "Found nasm: but x86_64 with x32 ABI is not supported")
+  endif()
+  if(${_support_x64_and_avx512})
+    message(STATUS "Found nasm: best -- capable of assembling AVX512")
+  endif()
+  if(${_support_x64_and_avx2})
+    message(STATUS "Found nasm: better -- capable of assembling AVX2")
+  endif()
+  if(${_support_x64})
+    message(STATUS "Found nasm: good -- capable of assembling x86_64")
+  endif()
+endmacro()
-- 
2.39.5