[build][android] Use a CMake toolchain file to cross-compile Testing

Author: finagolfin

utils/swift_build_support/swift_build_support/products/product.py

@@ -409,18 +409,34 @@ def generate_linux_toolchain_file(self, platform, arch, crosscompiling=True):
         toolchain_args = {}
 
         if crosscompiling:
-            toolchain_args['CMAKE_SYSTEM_NAME'] = 'Linux'
-            toolchain_args['CMAKE_SYSTEM_PROCESSOR'] = arch
+            if platform == "linux":
+                toolchain_args['CMAKE_SYSTEM_NAME'] = 'Linux'
+                toolchain_args['CMAKE_SYSTEM_PROCESSOR'] = arch
+            elif platform == "android":
+                toolchain_args['CMAKE_SYSTEM_NAME'] = 'Android'
+                toolchain_args['CMAKE_SYSTEM_VERSION'] = self.args.android_api_level
+                toolchain_args['CMAKE_SYSTEM_PROCESSOR'] = self.args.android_arch \
+                    if not self.args.android_arch == 'armv7' else 'armv7-a'
+                toolchain_args['CMAKE_ANDROID_NDK'] = self.args.android_ndk
+                toolchain_args['CMAKE_FIND_ROOT_PATH'] = self.args.cross_compile_deps_path
+                # This is a workaround for a CMake 3.30+ bug,
+                # https://gitlab.kitware.com/cmake/cmake/-/issues/26154, and can
+                # be removed once that is fixed.
+                toolchain_args['CMAKE_SHARED_LINKER_FLAGS'] = '\"\"'
 
         # We only set the actual sysroot if we are actually cross
         # compiling. This is important since otherwise cmake seems to change the
         # RUNPATH to be a relative rather than an absolute path, breaking
         # certain cmark tests (and maybe others).
-        maybe_sysroot = self.get_linux_sysroot(platform, arch)
-        if maybe_sysroot is not None:
-            toolchain_args['CMAKE_SYSROOT'] = maybe_sysroot
-
-        target = self.get_linux_target(platform, arch)
+        if platform == "linux":
+            maybe_sysroot = self.get_linux_sysroot(platform, arch)
+            if maybe_sysroot is not None:
+                toolchain_args['CMAKE_SYSROOT'] = maybe_sysroot
+
+            target = self.get_linux_target(platform, arch)
+        elif platform == "android":
+            target = '%s-unknown-linux-android%s' % (self.args.android_arch,
+                                                     self.args.android_api_level)
         if self.toolchain.cc.endswith('clang'):
             toolchain_args['CMAKE_C_COMPILER_TARGET'] = target
         if self.toolchain.cxx.endswith('clang++'):
@@ -466,10 +482,30 @@ def generate_toolchain_file_for_darwin_or_linux(
                 platform, arch,
                 macos_deployment_version=override_macos_deployment_version)
             self.cmake_options.define('CMAKE_TOOLCHAIN_FILE:PATH', toolchain_file)
-        elif platform == "linux":
-            toolchain_file = self.generate_linux_toolchain_file(platform, arch)
+        elif platform == "linux" or platform == "android":
+            # Always cross-compile for linux, but not on Android, as a native
+            # compile on Android does not use the NDK and its CMake config.
+            cross_compile = platform == "linux" or \
+                self.is_cross_compile_target(host_target)
+            toolchain_file = self.generate_linux_toolchain_file(platform, arch,
+                                                                cross_compile)
             self.cmake_options.define('CMAKE_TOOLCHAIN_FILE:PATH', toolchain_file)
 
+            if cross_compile and platform == "android":
+                resource_dir = None
+                # build-script-impl products build before the install and use
+                # the Swift stdlib from the compiler build directory instead,
+                # while products built even before that currently do not support
+                # cross-compiling Swift.
+                if not self.is_before_build_script_impl_product() and \
+                   not self.is_build_script_impl_product():
+                    install_path = self.host_install_destdir(host_target) + \
+                        self.args.install_prefix
+                    resource_dir = '%s/lib/swift' % install_path
+                flags = targets.StdlibDeploymentTarget.get_target_for_name(
+                    host_target).platform.swift_flags(self.args, resource_dir)
+                self.cmake_options.define('CMAKE_Swift_FLAGS', flags)
+
         return toolchain_file
 
     def get_openbsd_toolchain_file(self):

utils/swift_build_support/swift_build_support/products/swift_testing.py

@@ -127,3 +127,11 @@ def install(self, host_target):
         install_prefix = install_destdir + self.args.install_prefix
 
         self.install_with_cmake(['install'], install_prefix)
+
+    @classmethod
+    def is_build_script_impl_product(cls):
+        return False
+
+    @classmethod
+    def is_before_build_script_impl_product(cls):
+        return False

utils/swift_build_support/swift_build_support/targets.py

@@ -72,7 +72,7 @@ def contains(self, target_name):
                 return True
         return False
 
-    def swift_flags(self, args):
+    def swift_flags(self, args, resource_path=None):
         """
         Swift compiler flags for a platform, useful for cross-compiling
         """
@@ -154,12 +154,15 @@ def uses_host_tests(self):
         """
         return True
 
-    def swift_flags(self, args):
+    def swift_flags(self, args, resource_path=None):
         flags = '-target %s-unknown-linux-android%s ' % (args.android_arch,
                                                          args.android_api_level)
 
-        flags += '-resource-dir %s/swift-%s-%s/lib/swift ' % (
-                 args.build_root, self.name, args.android_arch)
+        if resource_path is not None:
+            flags += '-resource-dir %s ' % (resource_path)
+        else:
+            flags += '-resource-dir %s/swift-%s-%s/lib/swift ' % (
+                     args.build_root, self.name, args.android_arch)
 
         android_toolchain_path = self.ndk_toolchain_path(args)