zephyr: twister: Allow overriding toolchain options

Allow overriding the TOOLCHAIN_ROOT and ZEPHYR_TOOLCHAIN_VARIANT
environment variables, as well as the --gcov-tool CLI parameter. This is
necessary for running tests with GCC outside of the chroot, such as in
Gitlab.

By default, the usual LLVM toolchain is used and there is no impact on
users.

BUG=b:242067249
BRANCH=None
TEST=./twister -v -v

Signed-off-by: Tristan Honscheid <honscheid@google.com>
Change-Id: I2369c251ac43d05bc0246d8e1b35e1bc4a28b783
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3831536
Reviewed-by: Jeremy Bettis <jbettis@chromium.org>
Commit-Queue: Jeremy Bettis <jbettis@chromium.org>

1 files changed, 20 insertions, 6 deletions

diff --git a/util/twister_launcher.py b/util/twister_launcher.py
index 9725aa03a6..aad4a05931 100755
--- a/util/twister_launcher.py
+++ b/util/twister_launcher.py
@@ -90,12 +90,16 @@ def main():
     zephyr_modules = find_modules(zephyr_modules_dir)
     zephyr_modules.append(ec_base)
 
-    # Prepare environment variables for export to Twister and inherit the
-    # parent environment.
+    # Prepare environment variables for export to Twister. Inherit the parent
+    # process's environment, but set some default values if not already set.
     twister_env = dict(os.environ)
     extra_env_vars = {
-        "TOOLCHAIN_ROOT": str(ec_base / "zephyr"),
-        "ZEPHYR_TOOLCHAIN_VARIANT": "llvm",
+        "TOOLCHAIN_ROOT": os.environ.get(
+            "TOOLCHAIN_ROOT", str(ec_base / "zephyr")
+        ),
+        "ZEPHYR_TOOLCHAIN_VARIANT": os.environ.get(
+            "ZEPHYR_TOOLCHAIN_VARIANT", "llvm"
+        ),
     }
     twister_env.update(extra_env_vars)
 
@@ -107,8 +111,6 @@ def main():
         f"-x=SYSCALL_INCLUDE_DIRS={str(ec_base / 'zephyr' / 'include' / 'drivers')}",
         f"-x=ZEPHYR_BASE={zephyr_base}",
         f"-x=ZEPHYR_MODULES={';'.join([str(p) for p in zephyr_modules])}",
-        "--gcov-tool",
-        ec_base / "util" / "llvm-gcov.sh",
     ]
 
     # `-T` flags (used for specifying test directories to build and run)
@@ -122,6 +124,9 @@ def main():
     parser = argparse.ArgumentParser(add_help=False, allow_abbrev=False)
     parser.add_argument("-T", "--testsuite-root", action="append")
     parser.add_argument("-v", "--verbose", action="count", default=0)
+    parser.add_argument(
+        "--gcov-tool", default=str(ec_base / "util" / "llvm-gcov.sh")
+    )
     intercepted_args, other_args = parser.parse_known_args()
 
     for _ in range(intercepted_args.verbose):
@@ -138,6 +143,15 @@ def main():
         twister_cli.extend(["-T", str(ec_base)])
         twister_cli.extend(["-T", str(zephyr_base / "tests/subsys/shell")])
 
+    # Pass through the chosen coverage tool, or fall back on the default choice
+    # (see add_argument above).
+    twister_cli.extend(
+        [
+            "--gcov-tool",
+            intercepted_args.gcov_tool,
+        ]
+    )
+
     # Append additional user-supplied args
     twister_cli.extend(other_args)