Add ability to compile recipes with clang

The android ndk has been migrated his default compiler from gcc to clang and soon will be removed from the ndk. Here we prepare p4a to compile recipes with clang, which will allow us to successfully compile an updated openssl libs. Without this openssl upgrade we will not be able to grant support to python3's _ssl.so module.

Note: The default p4a compiler still is gcc...so...no changes on the compile behaviour unless explicitly requested

References: #1478

Author: tito

pythonforandroid/archs.py

@@ -30,13 +30,24 @@ def include_dirs(self):
                 d.format(arch=self))
             for d in self.ctx.include_dirs]
 
-    def get_env(self, with_flags_in_cc=True):
+    def get_env(self, with_flags_in_cc=True, clang=False):
         env = {}
 
-        env['CFLAGS'] = ' '.join([
-            '-DANDROID', '-mandroid', '-fomit-frame-pointer'
-            ' -D__ANDROID_API__={}'.format(self.ctx.ndk_api),
-            ])
+        cflags = [
+            '-DANDROID',
+            '-fomit-frame-pointer',
+            '-D__ANDROID_API__={}'.format(self.ctx.ndk_api)]
+        if not clang:
+            cflags += ['-mandroid']
+        else:
+            cflags += ['-target armv7-none-linux-androideabi']
+            android_host = 'arm-linux-androideabi'
+            platform_dir = join(self.ctx.ndk_dir, 'platforms', 'android-{}'.format(self.ctx.ndk_api), 'arch-arm')
+            toolchain = '{android_host}-4.9'.format(android_host=android_host)
+            toolchain = join(self.ctx.ndk_dir, 'toolchains', toolchain, 'prebuilt', 'linux-x86_64')
+            cflags += ['-gcc-toolchain {}'.format(toolchain)]
+
+        env['CFLAGS'] = ' '.join(cflags)
         env['LDFLAGS'] = ' '
 
         sysroot = join(self.ctx._ndk_dir, 'sysroot')
@@ -82,8 +93,19 @@ def get_env(self, with_flags_in_cc=True):
             env['NDK_CCACHE'] = self.ctx.ccache
             env.update({k: v for k, v in environ.items() if k.startswith('CCACHE_')})
 
-        cc = find_executable('{command_prefix}-gcc'.format(
-            command_prefix=command_prefix), path=environ['PATH'])
+        if clang:
+            clang_path = join(
+                self.ctx.ndk_dir, 'toolchains', 'llvm', 'prebuilt',
+                'linux-x86_64', 'bin')
+            environ['PATH'] = '{clang_path}:{path}'.format(
+                clang_path=clang_path, path=environ['PATH'])
+            exe = join(clang_path, 'clang')
+            execxx = join(clang_path, 'clang++')
+        else:
+            exe = '{command_prefix}-gcc'.format(command_prefix=command_prefix)
+            execxx = '{command_prefix}-g++'.format(command_prefix=command_prefix)
+
+        cc = find_executable(exe, path=environ['PATH'])
         if cc is None:
             print('Searching path are: {!r}'.format(environ['PATH']))
             warning('Couldn\'t find executable for CC. This indicates a '
@@ -93,20 +115,20 @@ def get_env(self, with_flags_in_cc=True):
             exit(1)
 
         if with_flags_in_cc:
-            env['CC'] = '{ccache}{command_prefix}-gcc {cflags}'.format(
-                command_prefix=command_prefix,
+            env['CC'] = '{ccache}{exe} {cflags}'.format(
+                exe=exe,
                 ccache=ccache,
                 cflags=env['CFLAGS'])
-            env['CXX'] = '{ccache}{command_prefix}-g++ {cxxflags}'.format(
-                command_prefix=command_prefix,
+            env['CXX'] = '{ccache}{execxx} {cxxflags}'.format(
+                execxx=execxx,
                 ccache=ccache,
                 cxxflags=env['CXXFLAGS'])
         else:
-            env['CC'] = '{ccache}{command_prefix}-gcc'.format(
-                command_prefix=command_prefix,
+            env['CC'] = '{ccache}{exe}'.format(
+                exe=exe,
                 ccache=ccache)
-            env['CXX'] = '{ccache}{command_prefix}-g++'.format(
-                command_prefix=command_prefix,
+            env['CXX'] = '{ccache}{execxx}'.format(
+                execxx=execxx,
                 ccache=ccache)
 
         env['AR'] = '{}-ar'.format(command_prefix)
@@ -151,8 +173,8 @@ class ArchARM(Arch):
 class ArchARMv7_a(ArchARM):
     arch = 'armeabi-v7a'
 
-    def get_env(self, with_flags_in_cc=True):
-        env = super(ArchARMv7_a, self).get_env(with_flags_in_cc)
+    def get_env(self, with_flags_in_cc=True, clang=False):
+        env = super(ArchARMv7_a, self).get_env(with_flags_in_cc, clang=clang)
         env['CFLAGS'] = (env['CFLAGS'] +
                          (' -march=armv7-a -mfloat-abi=softfp '
                           '-mfpu=vfp -mthumb'))
@@ -166,8 +188,8 @@ class Archx86(Arch):
     command_prefix = 'i686-linux-android'
     platform_dir = 'arch-x86'
 
-    def get_env(self, with_flags_in_cc=True):
-        env = super(Archx86, self).get_env(with_flags_in_cc)
+    def get_env(self, with_flags_in_cc=True, clang=False):
+        env = super(Archx86, self).get_env(with_flags_in_cc, clang=clang)
         env['CFLAGS'] = (env['CFLAGS'] +
                          ' -march=i686 -mtune=intel -mssse3 -mfpmath=sse -m32')
         env['CXXFLAGS'] = env['CFLAGS']
@@ -180,8 +202,8 @@ class Archx86_64(Arch):
     command_prefix = 'x86_64-linux-android'
     platform_dir = 'arch-x86'
 
-    def get_env(self, with_flags_in_cc=True):
-        env = super(Archx86_64, self).get_env(with_flags_in_cc)
+    def get_env(self, with_flags_in_cc=True, clang=False):
+        env = super(Archx86_64, self).get_env(with_flags_in_cc, clang=clang)
         env['CFLAGS'] = (env['CFLAGS'] +
                          ' -march=x86-64 -msse4.2 -mpopcnt -m64 -mtune=intel')
         env['CXXFLAGS'] = env['CFLAGS']
@@ -194,8 +216,8 @@ class ArchAarch_64(Arch):
     command_prefix = 'aarch64-linux-android'
     platform_dir = 'arch-arm64'
 
-    def get_env(self, with_flags_in_cc=True):
-        env = super(ArchAarch_64, self).get_env(with_flags_in_cc)
+    def get_env(self, with_flags_in_cc=True, clang=False):
+        env = super(ArchAarch_64, self).get_env(with_flags_in_cc, clang=clang)
         incpath = ' -I' + join(dirname(__file__), 'includes', 'arm64-v8a')
         env['EXTRA_CFLAGS'] = incpath
         env['CFLAGS'] += incpath

pythonforandroid/recipe.py

@@ -406,12 +406,12 @@ def unpack(self, arch):
             else:
                 info('{} is already unpacked, skipping'.format(self.name))
 
-    def get_recipe_env(self, arch=None, with_flags_in_cc=True):
+    def get_recipe_env(self, arch=None, with_flags_in_cc=True, clang=False):
         """Return the env specialized for the recipe
         """
         if arch is None:
             arch = self.filtered_archs[0]
-        return arch.get_env(with_flags_in_cc=with_flags_in_cc)
+        return arch.get_env(with_flags_in_cc=with_flags_in_cc, clang=clang)
 
     def prebuild_arch(self, arch):
         '''Run any pre-build tasks for the Recipe. By default, this checks if