[Modules] Add 'no_undeclared_includes' module map attribute

The 'no_undeclared_includes' attribute should be used in a module to
tell that only non-modular headers and headers from used modules are
accepted.

The main motivation behind this is to prevent dep cycles between system
libraries (such as darwin) and libc++.

Patch by Richard Smith!

llvm-svn: 284797

1 files changed, 9 insertions, 0 deletions

diff --git a/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/module.modulemap b/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/module.modulemap
new file mode 100644
index 00000000000..b0ebe4b732e
--- /dev/null
+++ b/clang/test/Modules/Inputs/libc-libcxx/sysroot/usr/include/module.modulemap
@@ -0,0 +1,9 @@
+module libc [no_undeclared_includes] {
+  module math { header "math.h" export * }
+  module stdlib { header "stdlib.h" export * }
+  module stdatomic { header "stdatomic.h" export * }
+  module stddef { header "stddef.h" export * }
+  module stdint { header "stdint.h" export * }
+  module stdio { header "stdio.h" export * }
+  module util { header "util.h" export * }
+}