[llvm-dev] LLVM Weekly - #181, Jun 19th 2017

[Alex Bradbury via llvm-dev]

LLVM Weekly - #181, Jun 19th 2017
=================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/181>.

Welcome to the one hundred and eighty-first issue of LLVM Weekly, a weekly
newsletter (published every Monday) covering developments in LLVM, Clang, and
related projects. LLVM Weekly is brought to you by [Alex
Bradbury](http://asbradbury.org). Subscribe to future issues at
<http://llvmweekly.org> and pass it on to anyone else you think may be
interested. Please send any tips or feedback to <asb at asbradbury.org>, or
@llvmweekly or @asbradbury on Twitter.


## News and articles from around the web

Registration is [now
open](http://lists.llvm.org/pipermail/llvm-dev/2017-June/114220.html) for the
2017 LLVM Developers' Meeting. It will be held on October 18-19th in San Jose.
Registration fees are $300, with a student rate of $50. Additionally, there
will be a Women in Compilers and Tools pre-conference event on October 17th.

[hobbes](https://github.com/Morgan-Stanley/hobbes) is a newly released project
built on LLVM. As [described by its main
developer](http://lists.llvm.org/pipermail/llvm-dev/2017-June/114307.html), it
is a Haskell-family programming language, which can be used for analysis of
large data sets. It has been used in production within Morgan Stanley for
several years.

Scala Native 0.3.0 [has been
released](https://github.com/scala-native/scala-native/releases/tag/v0.3.0).
The main highlight is the new garbage collector, based on
[Immix](http://users.cecs.anu.edu.au/%7Esteveb/pubs/papers/immix-pldi-2008.pdf).


## On the mailing lists

* Quentin Colombet has sent an [update on the proposal to make GlobalISel the
default at O0 on
AArch64](http://lists.llvm.org/pipermail/llvm-dev/2017-June/114274.html). This
change has now been postponed, and you can read reasoning behind this in the
linked mailing list thread. One major concern was that enabling it by default
now may send the message that the design is set in stone and is ready for
broader adoption.

* Paul Robinson
[notes](http://lists.llvm.org/pipermail/llvm-dev/2017-June/114032.html) that
the total open bug count is now over 10000. He observes that the increase in
open bugs has been [remarkably
consistent](http://lists.llvm.org/pipermail/llvm-dev/attachments/20170612/b24b17b1/attachment.png).

* Alex Lorenz has shared an RFC on [adding refactoring support to
Clang](http://lists.llvm.org/pipermail/cfe-dev/2017-June/054286.html). This is
part of the effort to upstream features shipping in Xcode.

* Kuba Kuderski is interning at Google this summer and has shared an [RFC on
improving dominators in
LLVM](http://lists.llvm.org/pipermail/llvm-dev/2017-June/114045.html).

* Tanya Lattner is [seeking
volunteers](http://lists.llvm.org/pipermail/llvm-dev/2017-June/114140.html) to
help staff the LLVM stand at the 2017 Grace Hopper Conference. It will be held
October 4th-6th in Orlando.

* Hans Wennborg has shared the [proposed schedule for
5.0.0](http://lists.llvm.org/pipermail/llvm-dev/2017-June/114076.html). With
this release in particular, he is hoping for more community assistance with
the release management process.

* Michael Spencer has written an RFC on [profile guided section
layout](http://lists.llvm.org/pipermail/llvm-dev/2017-June/114178.html),
sharing initial results from his prototype implementation.


## LLVM commits

* `scavengeRegisterBackwards()` was added to the register scavenger. This has
the advantage over the previous `scavengeRegister()` functions of not being
dependent on the quality of the kill flags in the basic block.
[r305625](http://reviews.llvm.org/rL305625).

* The git-r utility has been added. This utility (written in Go) allows svn
revisions to be mapped to git revisions in the proposed LLVM mono-repository.
[r305598](http://reviews.llvm.org/rL305598).

* The stack coloring pass has been modified to be much less conservative.
[r305193](http://reviews.llvm.org/rL305193).

* llvm-pdbutil has seen a redesign of its "raw" output style.
[r305495](http://reviews.llvm.org/rL305495).

* Control flow integrity for indirect function calls in ThinLTO has been
implemented. [r305533](http://reviews.llvm.org/rL305533).


## Clang commits

* UBSan learned to detect invalid unsigned pointer index expressions.
[r305216](http://reviews.llvm.org/rL305216).

* Recent UBSan improvements are summarised in the draft release notes.
[r305269](http://reviews.llvm.org/rL305269).


## Other project commits

* LLDB's new `thread backtrace unique` command will de-duplicate the output
from threads that share the same call stacks. As noted in the commit message,
this is particularly useful for applications with large but mostly inactive
thread pools. [r305197](http://reviews.llvm.org/rL305197).

* LLD's monolithic Target.cpp has been split in to smaller files.
[r305565](http://reviews.llvm.org/rL305565).

* Polly can now compile all of Android, and uses this as part of its
automated testing. [r305334](http://reviews.llvm.org/rL305334).