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

[Vassil Vassilev via cfe-commits]

It could, it fixes a set of issues wrt to modules.
On 25/07/16 22:39, Hans Wennborg wrote:
> 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