[PATCH] D18213: Add a module Hash in the bitcode and the combined index.

[Mehdi Amini via llvm-commits]

> On Mar 16, 2016, at 9:26 AM, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> 
> On 16 March 2016 at 08:58, Mehdi AMINI <mehdi.amini at apple.com> wrote:
>> joker.eph created this revision.
>> joker.eph added reviewers: tejohnson, rafael.
>> joker.eph added a subscriber: llvm-commits.
>> 
>> Intended to be used for ThinLTO incremental build.
> 
> 
> Can you provide a description of how that will work?

Yes will do.

> 
> What is the time difference with and without when outputting a big bc
> file (LTO of clang for example)?

I'll crunch some numbers.

Note that this is only enabled when emitting a summary. So in a ThinLTO build it is emitted by the frontend/compile phase only. The LTO step is only a consumer of this information.

-- 
Mehdi