[libcxx] r227226 - [libcxx] Make __wrap_iter work with gcc.

[Nico Weber]

Author: nico
Date: Tue Jan 27 13:27:39 2015
New Revision: 227226

URL: http://llvm.org/viewvc/llvm-project?rev=227226&view=rev
Log:
[libcxx] Make __wrap_iter work with gcc.

he following snippet doesn't build when using gcc and libc++:

    #include <string>
    void f(const std::string& s) { s.begin(); }
    #include <vector>
    void AppendTo(const std::vector<char>& v) { v.begin(); }

The problem is that __wrap_iter has a private constructor. It lists vector<>
and basic_string<> as friends, but gcc seems to ignore this for vector<> for
some reason. Declaring vector before the friend declaration in __wrap_iter is
enough to work around this problem, so do that. With this patch, I'm able to
build chromium/android with libc++. Without it, two translation units fail to
build. (iosfwd already provides a forward declaration of basic_string.)

As far as I can tell, this is due to a gcc bug, which I filed as
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64816.

Fixes PR22355.

http://reviews.llvm.org/D7201

Added:
    libcxx/trunk/test/std/iterators/iterators.general/gcc_workaround.pass.cpp
Modified:
    libcxx/trunk/include/iterator

Modified: libcxx/trunk/include/iterator
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/iterator?rev=227226&r1=227225&r2=227226&view=diff
==============================================================================
--- libcxx/trunk/include/iterator (original)
+++ libcxx/trunk/include/iterator Tue Jan 27 13:27:39 2015
@@ -1112,6 +1112,8 @@ typename enable_if
 >::type
 __unwrap_iter(__wrap_iter<_Tp*>);
 
+template <class _Tp, class _Alloc> class _LIBCPP_TYPE_VIS_ONLY vector;
+
 template <class _Iter>
 class __wrap_iter
 {

Added: libcxx/trunk/test/std/iterators/iterators.general/gcc_workaround.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/iterators/iterators.general/gcc_workaround.pass.cpp?rev=227226&view=auto
==============================================================================
--- libcxx/trunk/test/std/iterators/iterators.general/gcc_workaround.pass.cpp (added)
+++ libcxx/trunk/test/std/iterators/iterators.general/gcc_workaround.pass.cpp Tue Jan 27 13:27:39 2015
@@ -0,0 +1,20 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// Tests workaround for  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64816.
+
+#include <string>
+
+void f(const std::string &s) { s.begin(); }
+
+#include <vector>
+
+void AppendTo(const std::vector<char> &v) { v.begin(); }
+
+int main() {}