r276473 - [modules] Teach the ASTWriter to ignore mutations coming from the ASTReader.

[Hans Wennborg via cfe-commits]

Should this be merged to 3.9?

On Fri, Jul 22, 2016 at 2:08 PM, Vassil Vassilev via cfe-commits
<cfe-commits at lists.llvm.org> wrote:
> Author: vvassilev
> Date: Fri Jul 22 16:08:24 2016
> New Revision: 276473
>
> URL: http://llvm.org/viewvc/llvm-project?rev=276473&view=rev
> Log:
> [modules] Teach the ASTWriter to ignore mutations coming from the ASTReader.
>
> Processing update records (and loading a module, in general) might trigger
> unexpected calls to the ASTWriter (being a mutation listener). Now we have a
> mechanism to suppress those calls to the ASTWriter but notify other possible
> mutation listeners.
>
> Fixes https://llvm.org/bugs/show_bug.cgi?id=28332
>
> Patch by Cristina Cristescu and me.
>
> Reviewed by Richard Smith (D21800).
>
> Added:
>     cfe/trunk/test/Modules/Inputs/PR28332/
>     cfe/trunk/test/Modules/Inputs/PR28332/TextualInclude.h
>     cfe/trunk/test/Modules/Inputs/PR28332/a.h
>     cfe/trunk/test/Modules/Inputs/PR28332/b.h
>     cfe/trunk/test/Modules/Inputs/PR28332/c.h
>     cfe/trunk/test/Modules/Inputs/PR28332/module.modulemap
>     cfe/trunk/test/Modules/pr28332.cpp
> Modified:
>     cfe/trunk/include/clang/Serialization/ASTReader.h
>     cfe/trunk/lib/Serialization/ASTReader.cpp
>     cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
>     cfe/trunk/lib/Serialization/ASTWriter.cpp