Module use declarations (II)

Review: http://llvm-reviews.chandlerc.com/D1546.

I have picked up this patch form Lawrence
(http://llvm-reviews.chandlerc.com/D1063) and did a few changes.

From the original change description (updated as appropriate):
This patch adds a check that ensures that modules only use modules they
have so declared. To this end, it adds a statement on intended module
use to the module.map grammar:

  use module-id

A module can then only use headers from other modules if it 'uses' them.
This enforcement is off by default, but may be turned on with the new
option -fmodules-decluse.

When enforcing the module semantics, we also need to consider a source
file part of a module. This is achieved with a compiler option

-fmodule-name=<module-id>.

The compiler at present only applies restrictions to the module directly
being built.

llvm-svn: 191283

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/test/Modules/declare-use1.cpp b/clang/test/Modules/declare-use1.cpp
new file mode 100644
index 00000000000..5bb7e2a47af
--- /dev/null
+++ b/clang/test/Modules/declare-use1.cpp
@@ -0,0 +1,7 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -x objective-c++ -fmodules-cache-path=%t -fmodules -fmodules-decluse -fmodule-name=G -I %S/Inputs/declare-use %s -verify
+
+#include "g.h"
+#include "e.h"
+#include "f.h" // expected-error {{use of a module not declared used}}
+const int g2 = g1+e+f;