Android build with Cross Compilation for BLAS and OpenCL back-ends

cross-files/aarch64-linux-android

@@ -0,0 +1,24 @@
+
+[host_machine]
+system = 'android'
+cpu_family = 'arm'
+cpu = 'aarch64'
+endian = 'little'
+
+[properties]
+needs_exe_wrapper = true
+cpp_args = ['-Dandroid']
+cpp_link_args = ['-ldl', '-llog', '-static-libstdc++']
+
+[paths]
+
+[binaries]
+c = 'aarch64-linux-android28-clang'
+cpp = 'aarch64-linux-android28-clang++'
+ar = 'aarch64-linux-android-ar'
+strip = 'aarch64-linux-android-strip'
+ld = 'aarch64-linux-android-ld'
+ranlib = 'aarch64-linux-android-ranlib'
+as = 'aarch64-linux-android-as'
+
+

cross-files/arm-linux-androideabi

@@ -0,0 +1,23 @@
+
+[host_machine]
+system = 'android'
+cpu_family = 'arm'
+cpu = 'armv7a'
+endian = 'little'
+
+[properties]
+needs_exe_wrapper = true
+cpp_args = ['-Dandroid']
+cpp_link_args = ['-ldl', '-llog', '-static-libstdc++']
+
+[paths]
+
+[binaries]
+c = 'armv7a-linux-androideabi28-clang'
+cpp = 'armv7a-linux-androideabi28-clang++'
+ar = 'arm-linux-androideabi-ar'
+strip = 'arm-linux-androideabi-strip'
+ld = 'arm-linux-androideabi-ld'
+ranlib = 'arm-linux-androideabi-ranlib'
+as = 'arm-linux-androideabi-as'
+

cross-files/arm-linux-gnueabi

@@ -0,0 +1,25 @@
+
+[host_machine]
+system = 'linux'
+cpu_family = 'arm'
+cpu = 'armv7'
+endian = 'little'
+
+[properties]
+needs_exe_wrapper = true
+cpp_args = []
+cpp_link_args = ['-ldl', '-latomic']
+c_link_args = ['-ldl', '-lpthread']
+
+[paths]
+
+[binaries]
+c = 'arm-linux-gnueabi-gcc'
+cpp = 'arm-linux-gnueabi-g++'
+ar = 'arm-linux-gnueabi-ar'
+strip = 'arm-linux-gnueabi-strip'
+ld = 'arm-linux-gnueabi-ld'
+ranlib = 'arm-linux-gnueabi-ranlib'
+as = 'arm-linux-gnueabi-as'
+pkgconfig = 'arm-linux-gnueabi-pkg-config'
+

cross_compilation.md

@@ -0,0 +1,19 @@
+
+# Cross compilation for Android, Linux ARM, etc.
+
+## Pre-requisites
+
+You'll need a toolchain like NDK or GNU ARM. A set of cross-files is provided, you can choose one of them or create your own. These are the platforms currently tested:
+
+* Android aarch64
+* Android armv7-a
+* Linux ARM
+
+## Build
+
+Once the toolchain is installed and a Meson cross file is chosen, to build simply run:
+
+`CC=clang CXX=clang++ ./build.sh --cross-file cross-files/arm-linux-androideabi`
+
+You might have to remove the build/ directory if it exists.
+

meson.build

@@ -27,7 +27,7 @@ if cc.get_id() == 'clang' or cc.get_id() == 'gcc'
   add_project_arguments('-Wextra', language : 'cpp')
   add_project_arguments('-pedantic', language : 'cpp')
 
-  if get_option('buildtype') == 'release'
+  if get_option('buildtype') == 'release' and cc.has_argument('-march=native')
     add_project_arguments('-march=native', language : 'cpp')
   endif
 endif
@@ -132,9 +132,11 @@ if host_machine.system() == 'windows'
   files += 'src/utils/filesystem.win32.cc'
 else
   files += 'src/utils/filesystem.posix.cc'
-  deps += [
-    cc.find_library('pthread'),
+  if host_machine.system() != 'android'
+    deps += [
+      cc.find_library('pthread'),
     ]
+  endif
 endif
 
 
@@ -296,24 +298,24 @@ if get_option('build_backends')
   ## OpenCL
   ## ~~~~~
 
-  has_opencl = false
+  opencl_dep = []
 
   opencl_libdirs = get_option('opencl_libdirs')
   opencl_lib=cc.find_library('OpenCL', dirs: opencl_libdirs, required: false)
 
   opencl_framework=dependency('OpenCL', required: false)
   if opencl_framework.found()
-      deps += [ opencl_framework ]
-      has_opencl = true
+      opencl_dep += [ opencl_framework ]
 
   elif opencl_lib.found()
 
-      deps += [ opencl_lib ]
-      has_opencl = true
+      opencl_dep += [ opencl_lib ]
+  else
+      opencl_dep += [ subproject('opencl').get_variable('opencl_dep') ]
 
   endif
 
-  if get_option('opencl') and has_opencl
+  if get_option('opencl')
 
     opencl_files = [
       'src/neural/opencl/network_opencl.cc',
@@ -329,6 +331,7 @@ if get_option('build_backends')
 
     includes += include_directories(get_option('opencl_include'))
     files += opencl_files
+    deps += opencl_dep
     has_backends = true
 
   endif

meson_options.txt

@@ -15,7 +15,7 @@ option('openblas_include',
 
 option('opencl_include',
        type: 'array',
-       value: ['/usr/include/'],
+#       value: ['/usr/include/'],
        description: 'Paths to OpenCL include directories')
 
 option('tensorflow_libdir',

src/neural/opencl/OpenCLTuner.cc

@@ -35,7 +35,13 @@
 
 #include "utils/logging.h"
 
+// Use the temporary directory on Android as the engine may run with restricted file access
+#ifdef android
+const auto TUNER_FILE_LOCAL = std::string("/data/local/tmp/leelaz_opencl_tuning");
+#else
 const auto TUNER_FILE_LOCAL = std::string("leelaz_opencl_tuning");
+#endif
+
 constexpr auto MAX_ERROR = 1e-4f;
 
 static void sgemmBatched_ref(const std::vector<float>& a,

subprojects/opencl.wrap

@@ -0,0 +1,4 @@
+[wrap-git]
+directory = opencl
+url = https://github.com/borg323/OpenCL-ICD-Loader.git
+revision = meson