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+#
+# Copyright OpenEmbedded Contributors
+#
+# SPDX-License-Identifier: MIT
+#
+
+import shutil
+import subprocess
+import tempfile
+from types import SimpleNamespace
+
+import oe.path
+from oeqa.selftest.case import OESelftestTestCase
+from oeqa.utils.commands import bitbake, get_bb_var, get_bb_vars
+
+class ToolchainTests(OESelftestTestCase):
+
+ def test_toolchain_switching(self):
+ """
+ Test that a configuration that uses GCC by default but clang for one
+ specific recipe does infact do that.
+ """
+
+ def extract_comment(objcopy, filename):
+ """
+ Using the specified `objcopy`, return the .comment segment from
+ `filename` as a bytes().
+ """
+ with tempfile.NamedTemporaryFile(prefix="comment-") as f:
+ cmd = [objcopy, "--dump-section", ".comment=" + f.name, filename]
+ subprocess.run(cmd, check=True)
+ # clang's objcopy writes to a temporary file and renames, so we need to re-open.
+ with open(f.name, "rb") as f2:
+ return f2.read()
+
+ def check_recipe(recipe, filename, override, comment_present, comment_absent=None):
+ """
+ Check that `filename` in `recipe`'s bindir contains `comment`, and
+ the overrides contain `override`.
+ """
+ d = SimpleNamespace(**get_bb_vars(("D", "bindir", "OBJCOPY", "OVERRIDES", "PATH"), target=recipe))
+
+ self.assertIn(override, d.OVERRIDES)
+
+ binary = oe.path.join(d.D, d.bindir, filename)
+
+ objcopy = shutil.which(d.OBJCOPY, path=d.PATH)
+ self.assertIsNotNone(objcopy)
+
+ comment = extract_comment(objcopy, binary)
+ self.assertIn(comment_present, comment)
+ if comment_absent:
+ self.assertNotIn(comment_absent, comment)
+
+
+ # GCC by default, clang for selftest-hello.
+ self.write_config("""
+TOOLCHAIN = "gcc"
+TOOLCHAIN:pn-selftest-hello = "clang"
+ """)
+
+ # Force these recipes to re-install so we can extract the .comments from
+ # the install directory, as they're stripped out of the final packages.
+ bitbake("m4 selftest-hello -C install")
+
+ # m4 should be built with GCC and only GCC
+ check_recipe("m4", "m4", "toolchain-gcc", b"GCC: (GNU)", b"clang")
+
+ # helloworld should be built with clang. We can't assert that GCC is not
+ # present as it will be linked against glibc which is built with GCC.
+ check_recipe("selftest-hello", "helloworld", "toolchain-clang", b"clang version")
Add a basic test for the toolchain switching code: set the toolchain to GCC by default but Clang for a specific recipe, and verify that two recipes are built with the expected compiler. This works because before we strip the installed binaries there is a .comment segment that contains the list of toolchains used. Signed-off-by: Ross Burton <ross.burton@arm.com> --- meta/lib/oeqa/selftest/cases/toolchain.py | 71 +++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 meta/lib/oeqa/selftest/cases/toolchain.py