[llvm-dev] LLVM Weekly - #262, January 7th 2019

[Alex Bradbury via llvm-dev]

LLVM Weekly - #262, January 7th 2019
====================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/262>.

Welcome to the two hundred and sixty-second 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](https://www.linkedin.com/in/alex-bradbury/). 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.

Today we are celebrating the fifth anniversary of LLVM Weekly (a previous
version of this mailing erroneously claimed a mere four years of continuous
service). The first issue was published on Jan 6th 2014 (the first Monday of
that year). It has been published every single Monday since, without fail.
Thank you for reading, and a special thanks to anyone who has contributed tips
or sent feedback.


## News and articles from around the web

Student Travel Grant applications for EuroLLVM 2019 are [now
open](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128782.html).

The final deadline for the CfP for the LLVM Performance Workshop at CGO'19 is
[this Wednesday, 9th
January](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128858.html).

The next Zurich LLVM Compiler Social will take place [on Thursday Jan
10th](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128894.html). It
features talks on IR extensions for vectorisation, RISC-V vector support in
LLVM, and on a 22nm FDSOI RISC-V vector implementation.


## On the mailing lists

* James Y Knight has [provided an
update](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128840.html) on
the LLVM git conversion project. A new conversion has been created at [the
previous URL](https://github.com/llvm-git-prototype). The git trailer format
is now used to specify the SVN revision and there have been changes to branch
names.

* Serge Guelton
[announces](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128844.html)
that most (hopefully all) Python scripts from llvm, clang, and test-suite
repositories have been updated to work with both Python 2 and Python 3.

* Matthew Davis has
[summarised](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128811.html)
the current state of the RFC and patch to add binary support to llvm-mca.

* Dean Michael Berris has [shared an
RFC](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128841.html) on
documentation for the XRay framework.

* Davide Italiano
[proposes](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128872.html)
removing `LLVM_ALWAYS_INLINE` from ADT classes. There seems to be full support
for this so far.

* Clement Courbet
[proposes](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128822.html)
adding an `-memeq-lib-function` flag to allow a user to specify a memeq
function, to be used as a more efficient alternative to memcmp when possible.
Hal Finkel
[details](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128851.html)
reasons why function-level or per-callsite attributes may be preferred.

* Petr Hosek [provides some
pointers](http://lists.llvm.org/pipermail/llvm-dev/2019-January/128869.html)
to how Fuchsia does a full cross-build of an LLVM+Clang toolchain.

* Jonas Devlieghere has [shared an
RFC](http://lists.llvm.org/pipermail/lldb-dev/2019-January/014530.html) on
capturing calls to LLDB's SB API in order to support the generation of
'reproducers'.


## LLVM commits

* BasicAA was updated to support arbitrary pointer sizes.
[r350220](https://reviews.llvm.org/rL350220).

* MemorySanitizer has been ported to the new pass manager.
[r350305](https://reviews.llvm.org/rL350305).

* The WebAssembly backed gained optimisations for irreducible control flow.
This reduces the size of malloc by 33%.
[r350367](https://reviews.llvm.org/rL350367).


## Clang commits

* The clangd codebase was clang-formatted.
[r350303](https://reviews.llvm.org/rL350303).

* A new `objc_externally_retained` attribute was added. This exposes clang's
notion of pseudo-strong variables in ObjC ARC.
[r350422](https://reviews.llvm.org/rL350422).


## Other project commits

* hwasan was modified to allow the hwasan allocator to deter to the system
allocator. This is necessary on Android as the interposition model means some
libraries may be using the system allocator and others using the hwasan
allocator. [r350427](https://reviews.llvm.org/rL350427).

* libcxx gained the option to build a static libc++ library that exports no
symbols ('hermetic static library').
[r350489](https://reviews.llvm.org/rL350489).