[Module map] Introduce a private module re-export directive.
Introduce a new "export_as" directive for top-level modules, which
indicates that the current module is a "private" module whose symbols
will eventually be exported through the named "public" module. This is
in support of a common pattern in the Darwin ecosystem where a single
public framework is constructed of several private frameworks, with
(currently) header duplication and some support from the linker.
Addresses rdar://problem/34438420.
llvm-svn: 313316
diff --git a/clang/test/Modules/export_as_test.c b/clang/test/Modules/export_as_test.c
new file mode 100644
index 0000000..a73d6bf
--- /dev/null
+++ b/clang/test/Modules/export_as_test.c
@@ -0,0 +1,9 @@
+// RUN: rm -rf %t
+// RUN: not %clang_cc1 -fmodules -fmodules-cache-path=%t -fmodule-map-file=%S/Inputs/export_as_test.modulemap %s 2> %t.err
+// RUN: FileCheck %s < %t.err
+
+// CHECK: export_as_test.modulemap:3:13: error: conflicting re-export of module 'PrivateFoo' as 'Foo' or 'Bar'
+// CHECK: export_as_test.modulemap:4:13: warning: module 'PrivateFoo' already re-exported as 'Bar'
+// CHECK: export_as_test.modulemap:7:15: error: only top-level modules can be re-exported as public
+
+