Just got the revision from pcc@. It's r308500.

Also would like r308504 and https://reviews.llvm.org/D35604 (once it lands) to fix some ThinLTO + cfi-icall related bugs.

When https://chromium-review.googlesource.com/c/575586/ lands I'd also like a clang roll (repackage really), to include libclang_rt.ios.a.  This will allow iOS to properly use @available.

(https://reviews.llvm.org/D35604 landed in r308642)

r308544 speeds up gdb index creation, which is relevant for  issue 735126 

Trying one at https://chromium-review.googlesource.com/c/582074

Need to remember to update 5.0.0 to 6.0.0 in this roll.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1c688af81fcfa4c072dcca79e698641839e8a42f

commit 1c688af81fcfa4c072dcca79e698641839e8a42f
Author: Nico Weber <thakis@chromium.org>
Date: Mon Jul 24 11:25:28 2017

Roll clang 307486:308728.

Ran `tools/clang/scripts/upload_revision.py 308728`.

This changes the clang version from 5.0.0 to 6.0.0, so simplify
some things that dealt with both numbers.

This changes clang to no longer look for libc++ headers in the
Fuchsia SDK.  To keep things building, use "our" libc++, like
on linux (use_custom_libcxx).  This in turn means we pass
-nodefaultlibs to the linker, which sadly also disables the
automatic linking of clang_rt.builtins, so do that manually now.
(In exchange, we no longer need to pass in -resource-dir.)

This makes -Wformat fire in Google Toolbox for Mac in iOS builds,
so disable -Wformat in that config for now.

Bug:  746303 , 746505 , 747638 , 747643 , 724204 

Change-Id: I6196a2a173a1b4871f22d0ce92436d0197fd7845
Reviewed-on: https://chromium-review.googlesource.com/582074
Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#488946}
[modify] https://crrev.com/1c688af81fcfa4c072dcca79e698641839e8a42f/build/config/c++/BUILD.gn
[modify] https://crrev.com/1c688af81fcfa4c072dcca79e698641839e8a42f/build/config/c++/c++.gni
[modify] https://crrev.com/1c688af81fcfa4c072dcca79e698641839e8a42f/build/config/fuchsia/BUILD.gn
[modify] https://crrev.com/1c688af81fcfa4c072dcca79e698641839e8a42f/build/toolchain/toolchain.gni
[modify] https://crrev.com/1c688af81fcfa4c072dcca79e698641839e8a42f/third_party/google_toolbox_for_mac/BUILD.gn
[modify] https://crrev.com/1c688af81fcfa4c072dcca79e698641839e8a42f/tools/clang/scripts/update.py

The roll's been in for a day, hopefully it'll stick. Fallout so far is just  issue 747957  .