Add symbol checking script to libc++ to help manage exported symbols.

Summary:
Add symbol checking scripts for extracting a list of symbols from shared libraries and for comparing symbol lists for differences.



Reviewers: mclow.lists, danalbert, EricWF

Reviewed By: EricWF

Subscribers: majnemer, emaste, cfe-commits

Differential Revision: http://reviews.llvm.org/D4946

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@232855 91177308-0d34-0410-b5e6-96231b3b80d8

utils/sym_check/sym_extract.py

@@ -0,0 +1,29 @@
+#!/usr/bin/env python
+"""
+sym_extract - Extract and output a list of symbols from a shared library.
+"""
+from argparse import ArgumentParser
+from sym_check import extract, util
+
+
+def main():
+    parser = ArgumentParser(
+        description='Extract a list of symbols from a shared library.')
+    parser.add_argument('library', metavar='shared-lib', type=str,
+                        help='The library to extract symbols from')
+    parser.add_argument('-o', '--output', dest='output',
+                        help='The output file. stdout is used if not given',
+                        type=str, action='store', default=None)
+    parser.add_argument('--names-only', dest='names_only',
+                        help='Output only the name of the symbol',
+                        action='store_true', default=False)
+    args = parser.parse_args()
+    if args.output is not None:
+        print('Extracting symbols from %s to %s.'
+              % (args.library, args.output))
+    syms = extract.extract_symbols(args.library)
+    util.write_syms(syms, out=args.output, names_only=args.names_only)
+
+
+if __name__ == '__main__':
+    main()