From 08305aaf6e3012b4a3080ea84d966d0dfdc736ad Mon Sep 17 00:00:00 2001
From: Eric Fiselier <eric@efcs.ca>
Date: Wed, 18 Jan 2017 00:05:01 +0000
Subject: [PATCH] Allow sym_diff.py to report non-zero for non-breaking ABI
 changes

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292297 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/abi/CMakeLists.txt            |  3 ++-
 utils/sym_check/sym_check/diff.py |  4 +++-
 utils/sym_check/sym_diff.py       | 14 +++++++++-----
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/lib/abi/CMakeLists.txt b/lib/abi/CMakeLists.txt
index e3eb3bf39..41240d72e 100644
--- a/lib/abi/CMakeLists.txt
+++ b/lib/abi/CMakeLists.txt
@@ -22,7 +22,8 @@ if (LIBCXX_HAS_ABILIST_CONFIGURATION)
     set(ABILIST_FILE "${CMAKE_CURRENT_LIST_DIR}/${TARGET_TRIPLE}.abilist")
     set(SYMDIFF_EXE "${LIBCXX_SOURCE_DIR}/utils/sym_check/sym_diff.py")
     add_custom_target(check-cxx-abilist
-            ${SYMDIFF_EXE} --only-stdlib-symbols ${ABILIST_FILE} $<TARGET_SONAME_FILE:cxx_shared>
+            ${SYMDIFF_EXE} --only-stdlib-symbols --strict ${ABILIST_FILE}
+            $<TARGET_SONAME_FILE:cxx_shared>
             DEPENDS cxx_shared
             COMMENT "Testing ABI compatibility...")
 endif()
diff --git a/utils/sym_check/sym_check/diff.py b/utils/sym_check/sym_check/diff.py
index 6502a4819..c89c4ef69 100644
--- a/utils/sym_check/sym_check/diff.py
+++ b/utils/sym_check/sym_check/diff.py
@@ -98,4 +98,6 @@ def report_diff(added_syms, removed_syms, changed_syms, names_only=False,
             report += 'ABI BREAKAGE: SYMBOLS ADDED OR REMOVED!'
     else:
         report += 'Symbols match.'
-    return report, int(abi_break)
+    is_different = abi_break or bool(len(added_syms)) \
+                   or bool(len(changed_syms))
+    return report, abi_break, is_different
diff --git a/utils/sym_check/sym_diff.py b/utils/sym_check/sym_diff.py
index 842e908dd..631f9c6b4 100755
--- a/utils/sym_check/sym_diff.py
+++ b/utils/sym_check/sym_diff.py
@@ -30,6 +30,10 @@ def main():
     parser.add_argument('--only-stdlib-symbols', dest='only_stdlib',
                         help="Filter all symbols not related to the stdlib",
                         action='store_true', default=False)
+    parser.add_argument('--strict', dest='strict',
+                        help="Exit with a non-zero status if any symbols "
+                             "differ",
+                        action='store_true', default=False)
     parser.add_argument(
         '-o', '--output', dest='output',
         help='The output file. stdout is used if not given',
@@ -54,16 +58,16 @@ def main():
     added, removed, changed = diff.diff(old_syms_list, new_syms_list)
     if args.removed_only:
         added = {}
-    report, is_break = diff.report_diff(added, removed, changed,
-                                        names_only=args.names_only,
-                                        demangle=args.demangle)
+    report, is_break, is_different = diff.report_diff(
+        added, removed, changed, names_only=args.names_only,
+        demangle=args.demangle)
     if args.output is None:
         print(report)
     else:
         with open(args.output, 'w') as f:
             f.write(report + '\n')
-    sys.exit(is_break)
-
+    exit_code = 1 if is_break or (args.strict and is_different) else 0
+    sys.exit(exit_code)
 
 if __name__ == '__main__':
     main()