mk: Generate a .def file for rustc_llvm on MSVC

Windows needs explicit exports of functions from DLLs but LLVM does not mention
any of its symbols as being export-able from a DLL. The compiler, however,
relies on being able to use LLVM symbols across DLL boundaries so we need to
force many of LLVM's symbols to be exported from `rustc_llvm.dll`. This commit
adds support for generation of a `rustc_llvm.def` file which is passed along to
the linker when generating `rustc_llvm.dll` which should keep all these symbols
exportable and usable.

1 files changed, 25 insertions, 0 deletions

diff --git a/src/etc/mklldef.py b/src/etc/mklldef.py
new file mode 100644
index 00000000000..d2f8ee469a4
--- /dev/null
+++ b/src/etc/mklldef.py
@@ -0,0 +1,25 @@
+# Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+# file at the top-level directory of this distribution and at
+# http://rust-lang.org/COPYRIGHT.
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+import sys
+
+input_file = sys.argv[1]
+output_file = sys.argv[2]
+name = sys.argv[3]
+
+with open(input_file, 'r') as f:
+    with open(output_file, 'w') as g:
+        print >> g, 'LIBRARY ' + name
+        print >> g, 'EXPORTS'
+        for x in f:
+            x = str(x)
+            if not x.startswith('    pub fn LLVM'): continue
+            name = x[11:x.find('(')]
+            print >> g, '  ' + name