[PATCH] Modules: Make missing headers in a module.map a warning not an error.

[Daniel Jasper]

  I added tests and changed the implementation to now instead:
  * Store information about the header directive for missing headers
  * Provide an error diagnostic if a header file is not available and the module is used or built

  I think this might actually be a better step towards not actively stat-ing all headers in the module maps.


================
Comment at: lib/Lex/ModuleMap.cpp:1569
@@ +1568,3 @@
+    // If we find a module that has a missing header, we mark this module as
+    // unavailable. Layering warnings like -fmodules-decluse can still be used.
+    ActiveModule->IsAvailable = false;
----------------
Richard Smith wrote:
> Presumably other submodules of the same module can still be built and used, too? (I don't think there's anything specific to layering warnings here?)
Changed comment.


http://llvm-reviews.chandlerc.com/D2352