[Modules TS] Added module re-export support.

This implements [dcl.modules.export] from the C++ Modules TS, which lets a module re-export another module with the "export import" syntax.
Differential Revision: https://reviews.llvm.org/D40270

llvm-svn: 318744

2 files changed, 40 insertions, 4 deletions

diff --git a/clang/test/CXX/modules-ts/dcl.dcl/dcl.module/dcl.module.export/p1.cpp b/clang/test/CXX/modules-ts/dcl.dcl/dcl.module/dcl.module.export/p1.cpp
new file mode 100644
index 00000000000..ab8c690441c
--- /dev/null
+++ b/clang/test/CXX/modules-ts/dcl.dcl/dcl.module/dcl.module.export/p1.cpp
@@ -0,0 +1,40 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+//
+// RUN: echo 'export module a; export class A{};' | %clang_cc1 -x c++ -fmodules-ts -emit-module-interface - -o %t/a.pcm
+// RUN: echo 'export module b; export class B{};' | %clang_cc1 -x c++ -fmodules-ts -emit-module-interface - -o %t/b.pcm
+// RUN: echo 'export module c; export class C{};' | %clang_cc1 -x c++ -fmodules-ts -emit-module-interface - -o %t/c.pcm
+//
+// RUN: %clang_cc1 -fmodules-ts -fprebuilt-module-path=%t -emit-module-interface %s -o %t/aggregate.internal.pcm -DAGGREGATE_INTERNAL
+// RUN: %clang_cc1 -fmodules-ts -fprebuilt-module-path=%t -emit-module-interface %s -o %t/aggregate.pcm -DAGGREGATE
+//
+// RUN: %clang_cc1 -fmodules-ts -fprebuilt-module-path=%t %s -verify -DTEST
+// expected-no-diagnostics
+
+
+#ifdef AGGREGATE_INTERNAL
+export module aggregate.internal;
+export import a;
+export {
+  import b;
+  import c;
+}
+#endif
+
+
+// Export the above aggregate module.
+// This is done to ensure that re-exports are transitive.
+#ifdef AGGREGATE
+export module aggregate;
+export import aggregate.internal;
+#endif
+
+
+// For the actual test, just try using the classes from the exported modules
+// and hope that they're accessible.
+#ifdef TEST
+import aggregate;
+A a;
+B b;
+C c;
+#endif
diff --git a/clang/test/SemaCXX/modules-ts.cppm b/clang/test/SemaCXX/modules-ts.cppm
index f64a4c0ab41..c07ee82e313 100644
--- a/clang/test/SemaCXX/modules-ts.cppm
+++ b/clang/test/SemaCXX/modules-ts.cppm
@@ -52,10 +52,6 @@ export {} // expected-error {{export declaration cannot be empty}}
 export { ; }
 export { static_assert(true); }
 
-// FIXME: These diagnostics are not very good.
-export import foo; // expected-error {{expected unqualified-id}}
-export { import foo; } // expected-error {{expected unqualified-id}}
-
 int use_b = b;
 int use_n = n; // FIXME: this should not be visible, because it is not exported