Fix cross compiling for android on macOS (#997)

foreign_cc/cmake.bzl

@@ -148,6 +148,7 @@ load("//foreign_cc/private:transitions.bzl", "foreign_cc_rule_variant")
 load(
     "//foreign_cc/private/framework:platform.bzl",
     "os_name",
+    "target_os_name",
 )
 load(
     "//toolchains/native_tools:tool_access.bzl",
@@ -251,6 +252,7 @@ def _create_configure_script(configureParameters):
 
     configure_script = create_cmake_script(
         workspace_name = ctx.workspace_name,
+        target_os = target_os_name(ctx),
         generator = attrs.generator,
         cmake_path = attrs.cmake_path,
         tools = tools,

foreign_cc/private/cmake_script.bzl

@@ -19,6 +19,7 @@ def _escape_dquote_bash_crosstool(text):
 
 def create_cmake_script(
         workspace_name,
+        target_os,
         generator,
         cmake_path,
         tools,
@@ -37,6 +38,7 @@ def create_cmake_script(
 
     Args:
         workspace_name: current workspace name
+        target_os: The target OS for the build
         generator: The generator target for cmake to use
         cmake_path: The path to the cmake executable
         tools: cc_toolchain tools (CxxToolsInfo)
@@ -91,6 +93,14 @@ def create_cmake_script(
     if not params.cache.get("CMAKE_RANLIB"):
         params.cache.update({"CMAKE_RANLIB": ""})
 
+    # Avoid cmake passing wrong linker flags when targeting android on macOS
+    # https://github.com/bazelbuild/rules_foreign_cc/issues/289
+    if target_os == "android":
+        params.cache.update({
+            "ANDROID": "YES",
+            "CMAKE_SYSTEM_NAME": "Linux",
+        })
+
     set_env_vars = [
         "export {}=\"{}\"".format(key, _escape_dquote_bash(params.env[key]))
         for key in params.env

foreign_cc/private/framework.bzl

@@ -209,6 +209,7 @@ CC_EXTERNAL_RULE_ATTRIBUTES = {
         cfg = "exec",
         default = [],
     ),
+    "_android_constraint": attr.label(default = Label("@platforms//os:android")),
     # we need to declare this attribute to access cc_toolchain
     "_cc_toolchain": attr.label(
         default = Label("@bazel_tools//tools/cpp:current_cc_toolchain"),

foreign_cc/private/framework/platform.bzl

@@ -65,3 +65,20 @@ def os_name(ctx):
         return "unknown"
 
     return platform_info[ForeignCcPlatformInfo].os
+
+def target_os_name(ctx):
+    """A helper function for getting the target operating system name based on the constraints
+
+    Args:
+        ctx (ctx): The current rule's context object
+
+    Returns:
+        str: The string of the current platform
+    """
+    operating_systems = ["android"]
+    for os in operating_systems:
+        constraint = getattr(ctx.attr, "_{}_constraint".format(os))
+        if constraint and ctx.target_platform_has_constraint(constraint[platform_common.ConstraintValueInfo]):
+            return os
+
+    return "unknown"

test/cmake_text_tests.bzl

@@ -242,6 +242,7 @@ def _merge_flag_values_no_toolchain_file_test(ctx):
 
     script = create_cmake_script(
         "ws",
+        "unknown",
         "Unix Makefiles",
         "cmake",
         tools,
@@ -291,6 +292,7 @@ def _create_min_cmake_script_no_toolchain_file_test(ctx):
 
     script = create_cmake_script(
         "ws",
+        "unknown",
         "Ninja",
         "cmake",
         tools,
@@ -344,6 +346,7 @@ def _create_min_cmake_script_wipe_toolchain_test(ctx):
 
     script = create_cmake_script(
         "ws",
+        "unknown",
         "Ninja",
         "cmake",
         tools,
@@ -393,6 +396,7 @@ def _create_min_cmake_script_toolchain_file_test(ctx):
 
     script = create_cmake_script(
         "ws",
+        "unknown",
         "Ninja",
         "cmake",
         tools,
@@ -470,6 +474,7 @@ def _create_cmake_script_no_toolchain_file_test(ctx):
 
     script = create_cmake_script(
         "ws",
+        "unknown",
         "Ninja",
         "cmake",
         tools,
@@ -496,6 +501,71 @@ cmake -DCMAKE_AR="/cxx_linker_static" -DCMAKE_CXX_LINK_EXECUTABLE="became" -DCMA
 
     return unittest.end(env)
 
+def _create_cmake_script_android_test(ctx):
+    env = unittest.begin(ctx)
+
+    tools = CxxToolsInfo(
+        cc = "/some-cc-value",
+        cxx = "external/cxx-value",
+        cxx_linker_static = "/cxx_linker_static",
+        cxx_linker_executable = "ws/cxx_linker_executable",
+    )
+    flags = CxxFlagsInfo(
+        cc = ["-cc-flag", "-gcc_toolchain", "cc-toolchain"],
+        cxx = [
+            "--quoted=\"abc def\"",
+            "--sysroot=/abc/sysroot",
+            "--gcc_toolchain",
+            "cxx-toolchain",
+        ],
+        cxx_linker_shared = ["shared1", "shared2"],
+        cxx_linker_static = ["static"],
+        cxx_linker_executable = ["executable"],
+        assemble = ["assemble"],
+    )
+    user_env = {
+        "CC": "sink-cc-value",
+        "CFLAGS": "--from-env",
+        "CUSTOM_ENV": "YES",
+        "CXX": "sink-cxx-value",
+    }
+    user_cache = {
+        "CMAKE_ASM_FLAGS": "assemble-user",
+        "CMAKE_BUILD_TYPE": "user_type",
+        "CMAKE_CXX_LINK_EXECUTABLE": "became",
+        "CMAKE_C_FLAGS": "--additional-flag",
+        "CUSTOM_CACHE": "YES",
+    }
+
+    script = create_cmake_script(
+        "ws",
+        "android",
+        "Ninja",
+        "cmake",
+        tools,
+        flags,
+        "test_rule",
+        "external/test_rule",
+        True,
+        user_cache,
+        user_env,
+        ["--debug-output", "-Wdev"],
+        cmake_commands = [],
+    )
+    expected = r"""export CC="sink-cc-value"
+export CXX="sink-cxx-value"
+export CFLAGS="-cc-flag -gcc_toolchain cc-toolchain --from-env --additional-flag"
+export CXXFLAGS="--quoted=\\\"abc def\\\" --sysroot=/abc/sysroot --gcc_toolchain cxx-toolchain"
+export ASMFLAGS="assemble assemble-user"
+export CUSTOM_ENV="YES"
+##enable_tracing##
+cmake -DCMAKE_AR="/cxx_linker_static" -DCMAKE_CXX_LINK_EXECUTABLE="became" -DCMAKE_SHARED_LINKER_FLAGS="shared1 shared2" -DCMAKE_EXE_LINKER_FLAGS="executable" -DCMAKE_BUILD_TYPE="user_type" -DCUSTOM_CACHE="YES" -DCMAKE_INSTALL_PREFIX="test_rule" -DCMAKE_PREFIX_PATH="$$EXT_BUILD_DEPS$$" -DCMAKE_RANLIB="" -DANDROID="YES" -DCMAKE_SYSTEM_NAME="Linux" --debug-output -Wdev -G 'Ninja' $$EXT_BUILD_ROOT$$/external/test_rule
+##disable_tracing##
+"""
+    asserts.equals(env, expected.splitlines(), script)
+
+    return unittest.end(env)
+
 def _create_cmake_script_toolchain_file_test(ctx):
     env = unittest.begin(ctx)
 
@@ -533,6 +603,7 @@ def _create_cmake_script_toolchain_file_test(ctx):
 
     script = create_cmake_script(
         "ws",
+        "unknown",
         "Ninja",
         "cmake",
         tools,
@@ -592,6 +663,7 @@ create_min_cmake_script_no_toolchain_file_test = unittest.make(_create_min_cmake
 create_min_cmake_script_toolchain_file_test = unittest.make(_create_min_cmake_script_toolchain_file_test)
 create_cmake_script_no_toolchain_file_test = unittest.make(_create_cmake_script_no_toolchain_file_test)
 create_cmake_script_toolchain_file_test = unittest.make(_create_cmake_script_toolchain_file_test)
+create_cmake_script_android_test = unittest.make(_create_cmake_script_android_test)
 merge_flag_values_no_toolchain_file_test = unittest.make(_merge_flag_values_no_toolchain_file_test)
 create_min_cmake_script_wipe_toolchain_test = unittest.make(_create_min_cmake_script_wipe_toolchain_test)
 
@@ -609,6 +681,7 @@ def cmake_script_test_suite():
         create_min_cmake_script_toolchain_file_test,
         create_cmake_script_no_toolchain_file_test,
         create_cmake_script_toolchain_file_test,
+        create_cmake_script_android_test,
         merge_flag_values_no_toolchain_file_test,
         create_min_cmake_script_wipe_toolchain_test,
     )