[llvm-dev] LLVM Weekly - #353, October 5th 2020

[Alex Bradbury via llvm-dev]

LLVM Weekly - #353, October 5th 2020
====================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/353>.

Welcome to the three hundred and fifty-third 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.


## News and articles from around the web

The 2020 LLVM Virtual Developers' Meeting is taking place this week, October
6th-8th. The LLVM Foundation have announced [that registration will remain
open throughout the
conference](https://twitter.com/llvmorg/status/1312430761652498432). They've
also posted a [video tutorial on using the conferencing
software](https://www.youtube.com/watch?v=Qpbefagv6Ts).


## On the mailing lists

* ORC JIT Weekly #22 [is
out](http://lists.llvm.org/pipermail/llvm-dev/2020-September/145353.html) (in
fact it was out last week - apologies for missing it) with an overview of the
OrcV1 removable code feature. ORC JIT Weekly #23 [is also
out](http://lists.llvm.org/pipermail/llvm-dev/2020-October/145597.html),
providing updates on C API extensions, DefinitionGenerator changes, and OrcV1
removal.

* Kai Peter Nacke [proposed adding character set conversion to the LLVM
Support
library](http://lists.llvm.org/pipermail/llvm-dev/2020-October/145548.html).
This is motivated by the need to convert strings to/from EBCDIC and UTF-8 on
z/OS.

* Matt P. Dziubinski [asked about Padded SLP Automatic
Vectorization](http://lists.llvm.org/pipermail/llvm-dev/2020-September/145386.html),
which was presented at CGO and EuroLLVM 2015. Vasileios Porpodas, one of the
paper's authors [provided insight on PSLP features still not supported in the
current SLP
pass](http://lists.llvm.org/pipermail/llvm-dev/2020-October/145578.html).

* LLVM 11.0.0-rc5 [has now been
tagged](http://lists.llvm.org/pipermail/llvm-dev/2020-September/145474.html).

* Fangrui Song provided an [update on recent binutils / GNU ABI
extensions](http://lists.llvm.org/pipermail/llvm-dev/2020-September/145443.html)
that may affect LLD and LLVM binary utilities.

* Pavel Labath responded to the [RFC on processor trace support in
LLDB](http://lists.llvm.org/pipermail/lldb-dev/2020-October/016469.html),
kicking off a discussion about handling of multi-process traces.

* Anastasia Stulova [proposes a set of simplifications in the OpenCL extension
implementation](http://lists.llvm.org/pipermail/cfe-dev/2020-September/066911.html).

* Saleem Abdulrasol [revived discussion of adding APINotes support to
Clang](http://lists.llvm.org/pipermail/cfe-dev/2020-September/066901.html).
Gábor Márton [gave details on how this could be useful for the Clang Static
Analyzer](http://lists.llvm.org/pipermail/cfe-dev/2020-September/066906.html).

* Nithin Vadukkumchery Rajendrakumar shared an [end of project report on the
project "Find null smart
pointer dereferences with the LLVM-Clang Static
Analyzer"](http://lists.llvm.org/pipermail/cfe-dev/2020-September/066902.html),
done as part of Google Summer of Code.


## LLVM commits

* Support was added for Intel's Key Locker feature.
[413577a](https://reviews.llvm.org/rG413577a8790).

* RegAllocFast was largely rewritten.
[89baeae](https://reviews.llvm.org/rG89baeaef2fa).

* A pass to flatten nested loops was added.
[d53b4be](https://reviews.llvm.org/rGd53b4bee0cc).

* Coroutines will now reuse storage for local variables with non-overlapping
lifetimes. [b3a722e](https://reviews.llvm.org/rGb3a722e66b7).

* Exception support was added for basic block sections.
[8955950](https://reviews.llvm.org/rG8955950c121).

* A new `-print-changed` option was added which only prints IR when its been
changed. [71124a9](https://reviews.llvm.org/rG71124a9dbdc).

* A Cortex-R82 CPU definition was added.
[8825fec3](https://reviews.llvm.org/rG8825fec37e7).

* The new PrintDetailedRecords TableGen backend (accessible via
`--print-detailed-records`) will print all global variables, classes, and
records defined in the input .td files.
[0c1bb4f8](https://reviews.llvm.org/rG0c1bb4f8851).


## Clang commits

* The new readability-function-cognitive-complexity check can be used to check
for functions exceeding a configured Cognitive Complexity limit.
[ace6440](https://reviews.llvm.org/rGace644030e6).

* A trained decision forest model can now be used for clangd code completion.
[b5f7e9e](https://reviews.llvm.org/rGb5f7e9e26cd),
[a8b55b6](https://reviews.llvm.org/rGa8b55b6939a).

* The new `-fprofile-update` option allows the atomicity of profile counter
increments to be specified.
[3681be87](https://reviews.llvm.org/rG3681be876fe).

* clangd gained support for a new `--check` option that aims to allow easy
reproduction of crashes and errors without relying on a particular editor or
plugin. [79fbcbff](https://reviews.llvm.org/rG79fbcbff417).


## Other project commits

* An MLIR Async dialect was started.
[05a3b4f](https://reviews.llvm.org/rG05a3b4fe300).

* The LLD COFF linker will now merge debug types in parallel when using
ghashing. [49b3459](https://reviews.llvm.org/rG49b34599306).

* LLDB documentation can now be written in Markdown.
[8b95bd3](https://reviews.llvm.org/rG8b95bd3310c).