RunClang: Provide `__make_integer_seq` builtin when Clang does not

Visual Studio 2015 Update 2 (cl 19.00.23918) adds a `__make_integer_seq`
builtin.  It also started using the builtin in the `<type_traits>`
header.  Clang version 3.8 and above provide this builtin but older
versions do not, so CastXML fails when built against Clang 3.6 or 3.7.
Work around this problem by adding our own implementation of the builtin
when Clang does not provide it.

1 files changed, 36 insertions, 0 deletions

diff --git a/src/RunClang.cxx b/src/RunClang.cxx
index 0301388..e674ffc 100644
--- a/src/RunClang.cxx
+++ b/src/RunClang.cxx
@@ -240,6 +240,42 @@ protected:
           ;
       }
 
+#if LLVM_VERSION_MAJOR < 3 \
+ || LLVM_VERSION_MAJOR == 3 && LLVM_VERSION_MINOR < 8
+      // Clang 3.8 and above provide a __make_integer_seq builtin needed
+      // in C++14 mode.  Provide it ourselves for older Clang versions.
+      if (CI.getLangOpts().CPlusPlus14) {
+        builtins += "\n"
+          "template <typename _T, _T> struct __castxml__integral_constant;\n"
+          "template <template<typename _U, _U...> class _S,\n"
+          "          typename, typename, bool>\n"
+          "  struct __castxml__make_integer_seq_impl;\n"
+          "template <template<typename _U, _U...> class _S,\n"
+          "          class _T, _T... __v>\n"
+          "  struct __castxml__make_integer_seq_impl<_S,\n"
+          "       __castxml__integral_constant<_T, 0>,\n"
+          "       _S<_T, __v...>, true> {\n"
+          "     typedef _S<_T, __v...> type;\n"
+          "  };\n"
+          "template <template<typename _U, _U...> class _S,\n"
+          "          class _T, _T __i, _T... __v>\n"
+          "  struct __castxml__make_integer_seq_impl<_S,\n"
+          "       __castxml__integral_constant<_T, __i>,\n"
+          "       _S<_T, __v...>, true>\n"
+          "    : __castxml__make_integer_seq_impl<_S,\n"
+          "       __castxml__integral_constant<_T, __i - 1>,\n"
+          "       _S<_T, __i - 1, __v...>, __i >= 1 > {};\n"
+          "template <template<typename _U, _U...> class _S,\n"
+          "          typename _T, _T _Sz>\n"
+          "using __castxml__make_integer_seq = typename\n"
+          "  __castxml__make_integer_seq_impl<_S,\n"
+          "      __castxml__integral_constant<_T, _Sz>,\n"
+          "     _S<_T>, (_Sz>=0)>::type;\n"
+          "#define __make_integer_seq __castxml__make_integer_seq\n"
+          ;
+      }
+#endif
+
       // Prevent glibc use of a GNU extension not implemented by Clang.
       if (this->NeedNoMathInlines(this->Opts.Predefines)) {
         builtins += "\n"