From 8f7a32043d7a5498bf334e222c6beadba6195b24 Mon Sep 17 00:00:00 2001
From: Nico Weber <nicolasweber@gmx.de>
Date: Tue, 8 Oct 2019 23:08:18 +0000
Subject: [PATCH] gn build: unbreak libcxx build after r374116 by restoring
 gen_link_script.py for gn

llvm-svn: 374129
---
 llvm/utils/gn/secondary/libcxx/src/BUILD.gn        |  2 +-
 .../gn/secondary/libcxx/utils/gen_link_script.py   | 50 ++++++++++++++++++++++
 2 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100755 llvm/utils/gn/secondary/libcxx/utils/gen_link_script.py

diff --git a/llvm/utils/gn/secondary/libcxx/src/BUILD.gn b/llvm/utils/gn/secondary/libcxx/src/BUILD.gn
index 8f5c1c3..f96e4e0 100644
--- a/llvm/utils/gn/secondary/libcxx/src/BUILD.gn
+++ b/llvm/utils/gn/secondary/libcxx/src/BUILD.gn
@@ -230,7 +230,7 @@ if (libcxx_enable_shared) {
 
   if (libcxx_enable_abi_linker_script) {
     action("cxx_linker_script") {
-      script = "//libcxx/utils/gen_link_script.py"
+      script = "//llvm/utils/gn/secondary/libcxx/utils/gen_link_script.py"
       outputs = [
         "$runtimes_dir/libc++.so",
       ]
diff --git a/llvm/utils/gn/secondary/libcxx/utils/gen_link_script.py b/llvm/utils/gn/secondary/libcxx/utils/gen_link_script.py
new file mode 100755
index 0000000..485aa64
--- /dev/null
+++ b/llvm/utils/gn/secondary/libcxx/utils/gen_link_script.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+#===----------------------------------------------------------------------===##
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+#===----------------------------------------------------------------------===##
+
+"""
+Generate a linker script that links libc++ to the proper ABI library.
+An example script for c++abi would look like "INPUT(libc++.so.1 -lc++abi)".
+"""
+
+import argparse
+import os
+import sys
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--input", help="Path to libc++ library", required=True)
+    parser.add_argument("--output", help="Path to libc++ linker script",
+                        required=True)
+    parser.add_argument("libraries", nargs="+",
+                        help="List of libraries libc++ depends on")
+    args = parser.parse_args()
+
+    # Use the relative path for the libc++ library.
+    libcxx = os.path.relpath(args.input, os.path.dirname(args.output))
+
+    # Prepare the list of public libraries to link.
+    public_libs = ['-l%s' % l for l in args.libraries]
+
+    # Generate the linker script contents.
+    contents = "INPUT(%s)" % ' '.join([libcxx] + public_libs)
+
+    # Remove the existing libc++ symlink if it exists.
+    if os.path.islink(args.output):
+        os.unlink(args.output)
+
+    # Replace it with the linker script.
+    with open(args.output, 'w') as f:
+        f.write(contents + "\n")
+
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())
-- 
2.7.4