[build-script] Use a toolchain file and always cross compile cmark.

NOTE: We still build for the host platform always, but even in that case within
cmark itself, we are cross compiling it.

utils/swift_build_support/swift_build_support/products/cmark.py

@@ -10,8 +10,6 @@
 #
 # ----------------------------------------------------------------------------
 
-from build_swift.build_swift.wrappers import xcrun
-
 from . import cmake_product
 from . import earlyswiftdriver
 
@@ -61,20 +59,12 @@ def build(self, host_target):
            host_target.startswith("appletv") or \
            host_target.startswith("watch"):
 
-            cmake_os_sysroot = xcrun.sdk_path(platform)
-
-            cmake_osx_deployment_target = ''
-            if platform == "macosx":
-                cmake_osx_deployment_target = self.args.darwin_deployment_version_osx
-
             common_c_flags = ' '.join(self.common_cross_c_flags(platform, arch))
 
             self.cmake_options.define('CMAKE_C_FLAGS', common_c_flags)
             self.cmake_options.define('CMAKE_CXX_FLAGS', common_c_flags)
-            self.cmake_options.define('CMAKE_OSX_SYSROOT:PATH', cmake_os_sysroot)
-            self.cmake_options.define('CMAKE_OSX_DEPLOYMENT_TARGET',
-                                      cmake_osx_deployment_target)
-            self.cmake_options.define('CMAKE_OSX_ARCHITECTURES', arch)
+            toolchain_file = self.generate_darwin_toolchain_file(platform, arch)
+            self.cmake_options.define('CMAKE_TOOLCHAIN_FILE:PATH', toolchain_file)
 
         self.build_with_cmake(["all"], self.args.cmark_build_variant, [])
 

utils/swift_build_support/swift_build_support/products/product.py

@@ -13,7 +13,10 @@
 import abc
 import os
 
+from build_swift.build_swift.wrappers import xcrun
+
 from .. import cmake
+from .. import shell
 from .. import targets
 
 
@@ -204,14 +207,15 @@ def install_toolchain_path(self, host_target):
         return targets.toolchain_path(install_destdir,
                                       self.args.install_prefix)
 
+    def is_darwin_host(self, host_target):
+        return host_target.startswith("macosx") or \
+            host_target.startswith("iphone") or \
+            host_target.startswith("appletv") or \
+            host_target.startswith("watch")
+
     def should_include_host_in_lipo(self, host_target):
-        if self.args.cross_compile_hosts:
-            if host_target.startswith("macosx") or \
-               host_target.startswith("iphone") or \
-               host_target.startswith("appletv") or \
-               host_target.startswith("watch"):
-                return True
-        return False
+        return self.args.cross_compile_hosts and \
+            self.is_darwin_host(host_target)
 
     def host_install_destdir(self, host_target):
         if self.args.cross_compile_hosts:
@@ -233,38 +237,62 @@ def is_cross_compile_target(self, host_target):
         return self.args.cross_compile_hosts and \
             host_target in self.args.cross_compile_hosts
 
-    # TODO: Remove once we've moved over to cmake toolchains
-    def common_cross_c_flags(self, platform, arch):
-        cross_flags = []
+    def generate_darwin_toolchain_file(self, platform, arch):
+        shell.makedirs(self.build_dir)
+        toolchain_file = os.path.join(self.build_dir, 'BuildScriptToolchain.cmake')
 
+        cmake_osx_sysroot = xcrun.sdk_path(platform)
+
+        target = None
         if platform == 'macosx':
             target = '{}-apple-macosx{}'.format(
                 arch, self.args.darwin_deployment_version_osx)
-            cross_flags.extend(['-arch', arch, '-target', target])
         elif platform == 'iphonesimulator':
             target = '{}-apple-ios{}'.format(
                 arch, self.args.darwin_deployment_version_ios)
-            cross_flags.extend(['-arch', arch, '-target', target])
         elif platform == 'iphoneos':
             target = '{}-apple-ios{}'.format(
                 arch, self.args.darwin_deployment_version_ios)
-            cross_flags.extend(['-arch', arch, '-target', target])
         elif platform == 'appletvsimulator':
             target = '{}-apple-tvos{}'.format(
                 arch, self.args.darwin_deployment_version_tvos)
-            cross_flags.extend(['-arch', arch, '-target', target])
         elif platform == 'appletvos':
             target = '{}-apple-tvos{}'.format(
                 arch, self.args.darwin_deployment_version_tvos)
-            cross_flags.extend(['-arch', arch, '-target', target])
         elif platform == 'watchsimulator':
             target = '{}-apple-watchos{}'.format(
                 arch, self.args.darwin_deployment_version_watchos)
-            cross_flags.extend(['-arch', arch, '-target', target])
         elif platform == 'watchos':
             target = '{}-apple-watchos{}'.format(
                 arch, self.args.darwin_deployment_version_watchos)
-            cross_flags.extend(['-arch', arch, '-target', target])
+        else:
+            raise RuntimeError("Unhandled platform?!")
+
+        toolchain_args = {}
+
+        toolchain_args['CMAKE_SYSTEM_NAME'] = 'Darwin'
+        toolchain_args['CMAKE_OSX_SYSROOT'] = cmake_osx_sysroot
+        toolchain_args['CMAKE_OSX_ARCHITECTURES'] = arch
+
+        if self.toolchain.cc.endswith('clang'):
+            toolchain_args['CMAKE_C_COMPILER_TARGET'] = target
+        if self.toolchain.cxx.endswith('clang++'):
+            toolchain_args['CMAKE_CXX_COMPILER_TARGET'] = target
+        # Swift always supports cross compiling.
+        toolchain_args['CMAKE_Swift_COMPILER_TARGET'] = target
+
+        # Sort by the key so that we always produce the same toolchain file
+        data = sorted(toolchain_args.items(), key=lambda x: x[0])
+        if not self.args.dry_run:
+            with open(toolchain_file, 'w') as f:
+                f.writelines("set({} {})\n".format(k, v) for k, v in data)
+        else:
+            print("DRY_RUN! Writing Toolchain file to path: {}".format(toolchain_file))
+
+        return toolchain_file
+
+    def common_cross_c_flags(self, platform, arch):
+        cross_flags = []
 
         if self.is_release():
             cross_flags.append('-fno-stack-protector')

validation-test/BuildSystem/cmark_crosscompile_using_toolchain_always.test

@@ -0,0 +1,9 @@
+# REQUIRES: standalone_build
+# REQUIRES: OS=macosx
+
+# RUN: %empty-directory(%t)
+# RUN: mkdir -p %t
+# RUN: SKIP_XCODE_VERSION_CHECK=1 SWIFT_BUILD_ROOT=%t %swift_src_root/utils/build-script --dry-run --install-all --cmake %cmake --skip-build-llvm --skip-build-swift 2>&1 | %FileCheck %s
+
+# CHECK: DRY_RUN! Writing Toolchain file to path:{{.*}}BuildScriptToolchain.cmake
+# CHECK: cmake {{.*}}-DCMAKE_TOOLCHAIN_FILE:PATH={{.*}}BuildScriptToolchain.cmake {{.*}}cmark