[Modules] Add testcase for builtins used in umbrella headers

This used to work before r284797 + r285152, which exposed something
interesting; some users include builtins from umbrella headers.

Clang should emit a warning to warn users this is not a good practice
and umbrella headers shouldn't get the
implicitly-add-the-builtin-version behavior for builtin header names.

While we're not there, add the testcase to represent the way it
currently works.

llvm-svn: 285377

2 files changed, 9 insertions, 0 deletions

diff --git a/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/c++/v1/module.modulemap b/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/c++/v1/module.modulemap
index c352f4a6177..b06142a61a2 100644
--- a/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/c++/v1/module.modulemap
+++ b/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/c++/v1/module.modulemap
@@ -3,5 +3,8 @@ module "libc++" {
   module stdlib { header "stdlib.h" export * }
   module stddef { header "stddef.h" export * }
   module stdio { textual header "stdio.h" export * }
+  // FIXME: remove "textual" from stdint module below once the issue
+  // between umbrella headers and builtins is resolved.
+  module stdint { textual header "stdint.h" export * }
   module __config { header "__config" export * }
 }
diff --git a/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/c++/v1/stdint.h b/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/c++/v1/stdint.h
new file mode 100644
index 00000000000..7a68441bc3d
--- /dev/null
+++ b/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/c++/v1/stdint.h
@@ -0,0 +1,6 @@
+#ifndef LIBCXX_STDINT_H
+#define LIBCXX_STDINT_H
+
+#include_next "stdint.h"
+
+#endif