1 files changed, 66 insertions, 26 deletions
diff --git a/genconfig.py b/genconfig.py
index aebff35..e298b14 100755
--- a/genconfig.py
+++ b/genconfig.py
@@ -10,19 +10,20 @@ format of include/generated/autoconf.h in the Linux kernel.
 Optionally, also writes the configuration output as a .config file. See
 --config-out.
 
-Optionally, creates/updates a directory structure with one file per symbol that
-can be used to implement incremental builds. See the docstring for
-Kconfig.sync_deps() in kconfiglib.py.
+The --sync-deps, --file-list, and --env-list options generate information that
+can be used to avoid needless rebuilds/reconfigurations.
 
-Before writing a header file or other configuration output, Kconfiglib compares
-the old contents of the file against the new contents. If there's no change,
-the write is skipped. This avoids updating file metadata like the modification
-time, and might save work depending on your build setup.
+Before writing a header or configuration file, Kconfiglib compares the old
+contents of the file against the new contents. If there's no change, the write
+is skipped. This avoids updating file metadata like the modification time, and
+might save work depending on your build setup.
 
 By default, the configuration is generated from '.config'. A different
 configuration file can be passed in the KCONFIG_CONFIG environment variable.
 """
 import argparse
+import os
+import sys
 
 import kconfiglib
 
@@ -44,27 +45,47 @@ def main():
              .format(DEFAULT_HEADER_PATH))
 
     parser.add_argument(
+        "--config-out",
+        metavar="CONFIG_FILE",
+        help="""
+Write the configuration to CONFIG_FILE. This is useful if you include .config
+files in Makefiles, as the generated configuration file will be a full .config
+file even if .config is outdated. The generated configuration matches what
+olddefconfig would produce. If you use sync-deps, you can include
+deps/auto.conf instead. --config-out is meant for cases where incremental build
+information isn't needed.
+""")
+
+    parser.add_argument(
         "--sync-deps",
-        dest="sync_deps_path",
         metavar="OUTPUT_DIR",
         nargs="?",
         const=DEFAULT_SYNC_DEPS_PATH,
-        help="Enable generation of build dependency information for "
-             "incremental builds, optionally specifying the output path "
-             "(default: {})".format(DEFAULT_SYNC_DEPS_PATH))
+        help="""
+Enable generation of symbol dependency information for incremental builds,
+optionally specifying the output directory (default: {}). See the docstring of
+Kconfig.sync_deps() in Kconfiglib for more information.
+""".format(DEFAULT_SYNC_DEPS_PATH))
 
     parser.add_argument(
-        "--config-out",
-        dest="config_path",
-        metavar="CONFIG_FILE",
-        help="Write the configuration to the specified filename. "
-             "This is useful if you include .config files in Makefiles, as "
-             "the generated configuration file will be a full .config file "
-             "even if .config is outdated. The generated configuration "
-             "matches what olddefconfig would produce. If you use "
-             "--sync-deps, you can include deps/auto.conf instead. "
-             "--config-out is meant for cases where incremental build "
-             "information isn't needed.")
+        "--file-list",
+        metavar="OUTPUT_FILE",
+        help="""
+Write a list of all Kconfig files to OUTPUT_FILE, with one file per line. The
+paths are relative to $srctree (or to the current directory if $srctree is
+unset). Files appear in the order they're 'source'd.
+""")
+
+    parser.add_argument(
+        "--env-list",
+        metavar="OUTPUT_FILE",
+        help="""
+Write a list of all environment variables referenced in Kconfig files to
+OUTPUT_FILE, with one variable per line. Each line has the format NAME=VALUE.
+Only environment variables referenced with the preprocessor $(VAR) syntax are
+included, and not variables referenced with the older $VAR syntax (which is
+only supported for backwards compatibility).
+""")
 
     parser.add_argument(
         "kconfig_filename",
@@ -81,11 +102,30 @@ def main():
 
     kconf.write_autoconf(args.header_path)
 
-    if args.sync_deps_path is not None:
-        kconf.sync_deps(args.sync_deps_path)
+    if args.config_out is not None:
+        kconf.write_config(args.config_out, save_old=False)
+
+    if args.file_list is not None:
+        with _open_write(args.file_list) as f:
+            for path in kconf.kconfig_filenames:
+                f.write(path + "\n")
+
+    if args.env_list is not None:
+        with _open_write(args.env_list) as f:
+            for env_var in kconf.env_vars:
+                f.write("{}={}\n".format(env_var, os.environ[env_var]))
+
+    if args.sync_deps is not None:
+        kconf.sync_deps(args.sync_deps)
+
+
+def _open_write(path):
+    # Python 2/3 compatibility. io.open() is available on both, but makes
+    # write() expect 'unicode' strings on Python 2.
 
-    if args.config_path is not None:
-        kconf.write_config(args.config_path, save_old=False)
+    if sys.version_info[0] < 3:
+        return open(path, "w")
+    return open(path, "w", encoding="utf-8")
 
 
 if __name__ == "__main__":