Merge pull request #369 from chewi/cross

Fix cross-compiling by using CMAKE_SYSTEM_PROCESSOR and respecting -march|-mcpu

Author: liulanzheng

CMakeLists.txt

@@ -9,10 +9,8 @@ enable_language(C)
 set(CMAKE_CXX_FLAGS_RELEASE "-O2 -DNDEBUG")
 set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O2 -DNDEBUG -g")
 
-# Get CPU arch
-execute_process(COMMAND uname -m OUTPUT_VARIABLE ARCH OUTPUT_STRIP_TRAILING_WHITESPACE)
-if (NOT (${ARCH} STREQUAL x86_64) AND NOT (${ARCH} STREQUAL aarch64) AND NOT (${ARCH} STREQUAL arm64))
-    message(FATAL_ERROR "Unknown CPU architecture ${ARCH}")
+if (NOT (CMAKE_SYSTEM_PROCESSOR STREQUAL x86_64) AND NOT (CMAKE_SYSTEM_PROCESSOR STREQUAL aarch64) AND NOT (CMAKE_SYSTEM_PROCESSOR STREQUAL arm64))
+    message(FATAL_ERROR "Unknown CPU architecture ${CMAKE_SYSTEM_PROCESSOR}")
 endif ()
 
 option(OBD_VER "Overlaybd version" "overlaybd/0.0.0-undefined")
@@ -25,7 +23,7 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/CMake")
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fpic -Wall -Werror=sign-compare")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fpic -Wall -Werror=sign-compare -DOVERLAYBD_VER=${OBD_VER}")
 
-if (${ARCH} STREQUAL aarch64)
+if ((CMAKE_SYSTEM_PROCESSOR STREQUAL aarch64) OR (CMAKE_SYSTEM_PROCESSOR STREQUAL arm64))
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=armv8-a+crc -fsigned-char -fno-stack-protector -fomit-frame-pointer")
 endif ()
 

src/overlaybd/zfile/CMakeLists.txt

@@ -2,22 +2,23 @@ file(GLOB SOURCE_ZFILE "*.cpp")
 file(GLOB SOURCE_LZ4 "lz4/*.c")
 file(GLOB SOURCE_CRC32 "crc32/crc32c.cpp")
 
-# Get CPU arch
-execute_process(COMMAND uname -m OUTPUT_VARIABLE ARCH OUTPUT_STRIP_TRAILING_WHITESPACE)
-if (NOT (${ARCH} STREQUAL x86_64) AND NOT (${ARCH} STREQUAL aarch64))
-    message(FATAL_ERROR "Unknown CPU architecture ${ARCH}")
-endif ()
-
 set (CMAKE_CXX_STANDARD 17)
 add_library(crc32_lib STATIC ${SOURCE_CRC32})
 target_include_directories(crc32_lib PUBLIC
     ${PHOTON_INCLUDE_DIR}
 )
 
-if (${ARCH} STREQUAL x86_64)
+if (CMAKE_SYSTEM_PROCESSOR STREQUAL x86_64)
     target_compile_options(crc32_lib PUBLIC -msse4.2 -mcrc32)
 else()
-    target_compile_options(crc32_lib PRIVATE -march=native -mcpu=generic+crc)
+    if (NOT CMAKE_CXX_FLAGS MATCHES "-march=|-mcpu=")
+        check_cxx_compiler_flag(-mcpu=native COMPILER_HAS_NATIVE_FLAG)
+        if (COMPILER_HAS_NATIVE_FLAG)
+            target_compile_options(crc32_lib PRIVATE -mcpu=native)
+        else ()
+            target_compile_options(crc32_lib PRIVATE -mcpu=generic+crc)
+        endif ()
+    endif ()
 endif()
 
 if(ENABLE_DSA OR ENABLE_ISAL)