[llvm-dev] LLVM Weekly - #195, Sep 25th 2017

[Alex Bradbury via llvm-dev]

LLVM Weekly - #195, Sep 25th 2017
=================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/195>.

Welcome to the one hundred and ninety-fifth 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

Tanya Lattner is
[looking](http://lists.llvm.org/pipermail/llvm-dev/2017-September/117711.html)
for volunteers for the Hackers Lab at the upcoming LLVM Dev Meeting. "we are
asking for volunteers to represent a sub-project or topic related to the
meeting. These volunteers should be knowledgeable about the sub-project/topic
and able to answer some basic questions or point people to the right developer
to talk to. If volunteers want to go a step further, they could prepare a list
of bugs that groups could work on during the Hackers Lab."

Version 1.16 of the TTA-based code-design environment (TCE) has been
[released](http://lists.llvm.org/pipermail/llvm-dev/2017-September/117617.html).
This release includes support for LLVM 5.0.


## On the mailing lists

* Discussions have continued about the integration of Polly in to LLVM.
Johannes Doerfert has authored a [detailed
response](http://lists.llvm.org/pipermail/llvm-dev/2017-September/117604.html).
Following this discussion, Tobias Grosser has
[proposed](http://lists.llvm.org/pipermail/llvm-dev/2017-September/117698.html)
a process for integrating Polly into LLVM.

* Craig Topper is [looking for
feedback](http://lists.llvm.org/pipermail/llvm-dev/2017-September/117629.html)
on removing some old 'autoupgrade' code for very old LLVM bitcode. Paul
Robinson
[suggests](http://lists.llvm.org/pipermail/llvm-dev/2017-September/117680.html)
that a we need to consider a new policy for when the bitcode backwards
compatibility "guarantee" can be changed.


## Review corner

The LLVM Weekly review corner serves to highlight patches that are stuck
waiting awaiting review, or work from first-time contributors. See
[here](http://llvmweekly.org/reviewcorner) for more information and how to
submit you work for inclusion. Of course the hope is that highlighting these
patches will enable LLVM Weekly readers will step up and help to get them
merged. I'll be reporting back each week on any activity generated on these
patches, as well as sharing a new batch. If you want your patch included you
_must_ submit it via the linked form.

* "Test build gets gtest and gmock headers from local include directory on
FreeBSD, which breaks the build if those are different from headers included
in LLVM sources." [D37415](https://reviews.llvm.org/D37415), patch by Peter
Penzin.

* "This adds a better error diagnostic when deleting the evaluation of a
lambda expression. The [] of a lambda binds more closely to the delete, so
this error suggests adding parentheses, instead of the generic one currently
used ('expected expression')." [D36357](https://reviews.llvm.org/D36357),
patch by Nicolas Lesser.

* "Clarify Clang warnings about undefined behaviour for bitshifts. It happens
that the current output mislead users and makes them think that Clang is
wrong." [D30295](https://reviews.llvm.org/D30295), patch by Daniel Marjamäki.

* "This is regarding addition of a new priority selector/heuristic for
Scheduler DAG based scheduling. It adds a heuristic to pickup next instruction
to schedule if its operands have already been scheduled."
[D34596](https://reviews.llvm.org/D34596), patch by Jatin Bhateja.


## LLVM commits

* An initial version of a new llvm-cfi-verify tool has landed. It intends to
help verify protections inserted by LLVM's control-flow integrity schemes.
[r313809](http://reviews.llvm.org/rL313809).

* The BPF backend gained inline asm support
[rL313593](http://reviews.llvm.org/rL313593).

* Instructions have been written on how to request a patch be merged in to the
LLVM release branch. [r313608](http://reviews.llvm.org/rL313608).

* More detailed and accurate scheduling information was added for the Intel
Skylake Client micro-architecture.
[r313613](http://reviews.llvm.org/rL313613).

* TableGen performance when generating `-gen-dag-isel` has been improved,
making up for a performance regression introduced by support for parameterized
register classes. A later patch further improved runtime.
[r313647](http://reviews.llvm.org/rL313647),
[r313783](http://reviews.llvm.org/rL313783).


## Clang commits

* The 'noescape' attribute is now supported.
[r313945](http://reviews.llvm.org/rL313945).

* clang-format has been clang-formatted.
[r313744](http://reviews.llvm.org/rL313744).

* A new Cross Translation Unit support library has been introduced, which can
be used to load function definitions from external AST files.
[r313975](http://reviews.llvm.org/rL313975).


## Other project commits

* The speed of linking objects with `.gdb_index` has been improved.
[r314090](http://reviews.llvm.org/rL314090),
[r134092](http://reviews.llvm.org/rL314092).

* The LLDB test suite can be run against (developer) armv7 and arm64 iOS
devices. A public bot will soon be set up to report results.
[r314038](http://reviews.llvm.org/rL314038).

* What is a lit testing module? You can now read the documentation and find
out. [r313711](http://reviews.llvm.org/rL313711).