[llvm-dev] LLVM Weekly - #342, July 20th 2020

[Alex Bradbury via llvm-dev]

LLVM Weekly - #342, July 20th 2020
==================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/342>.

Welcome to the three hundred and forty-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.


## News and articles from around the web

Daniela Kutenin wrote up [his experience optimising 128-bit
division](https://danlark.org/2020/06/14/128-bit-division/), resulting in a
patch to compiler-rt.

LLVM Foundation President Tanya Lattner recently [took part in a video
interview](https://www.youtube.com/watch?v=vXHeHJY3CXI).

Vince Bridges will be [hosting an online LLVM
meetup](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143526.html) on Wed
July 22 at 6.30pm Central US time and will be presenting on how to write a new
static analysis checker.

LLVM 11 [has now
branched](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143415.html).

Clang developer Bruno Cardoso Lopes was a guest on [this week's
CppCast](https://cppcast.com/bruno-cardoso/), discussing clang modules and
pattern matching amongst other topics.


## On the mailing lists

* Rahman Lavaee
[proposed](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143512.html) a
section metadata based approach for mapping binary address to machine basic
blocks, contrasting the approach to the one used by
`-fbasicblock-sections=labels`.

* Nathan James posted an RFC on [adding support for line anchors to
FileCheck](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143521.html)
(numeric variables holding the value of the line number on which they were
defined).

* David Blaikie proposed [switching lld to match ld.bfd "tombstoning"
behaviour by
default](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143482.html). This
relates to resolving relocations from debug sections to dead code.

* Fangrui Song started a discussion about [specifying multiple independent
tests in one
file](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143373.html).

* ORC JIT Weekly #17 [is
out](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143532.html). Initial
JITLink support for ELF/x86-64 has landed, along with new APIs for target
process control.


## LLVM commits

* A new "expensive check" was added to ensure passes correctly set their
Modified status. [3667d87](https://reviews.llvm.org/rG3667d87a33d).

* The definitions of matrix operations in the language reference has been
tightened. [2b3c505](https://reviews.llvm.org/rG2b3c505d0f6).

* A machine learning-based native size estimator has been added for training
the -Oz inliner. [83080a2](https://reviews.llvm.org/rG83080a294ad).

* A new `check_ninja_deps.py` script was added to help spot missing
dependencies in the build scripts.
[86d362f](https://reviews.llvm.org/rG86d362f4892).

* Call Frame Information handling for basic block sections was committed.
[c3e6555](https://reviews.llvm.org/rGc3e6555616f).

* Guidance on omitting braces was updated.
[140c296](https://reviews.llvm.org/rG140c296ef51).

* ORC gained new TargetProcessControl and TPCIndirectionUtils APIs.
[0e940d5](https://reviews.llvm.org/rG0e940d55f8a).

* Work on llvm-libtool-darwin (an LLVM replacement of cctool's libtool) has
started. [6c43ed60](https://reviews.llvm.org/rG6c43ed608d5).


## Clang commits

* A new `-Wsuggest-override` warning was added.
[1111678](https://reviews.llvm.org/rG111167895d4).

* The Clang static analyzer benchmarking framework as added.
[5b4f143](https://reviews.llvm.org/rG5b4f1435645).

* Support was added for -mcpu for RISC-V.
[294d1ea](https://reviews.llvm.org/rG294d1eae75b).


## Other project commits

* MLIR started to gain support for lowering OpenMP parallel operations to LLVM
IR. [d9067dc](https://reviews.llvm.org/rGd9067dca7ba).

* MLIR gained a RegionKindInterface, which can be used to declare the kind of
an operation's contained region (e.g. SSACFG or Graph).
[6282886](https://reviews.llvm.org/rG628288658c5).

* The scudo secure memory allocator was tweaked to release smaller blocks less
often. [79de8f8](https://reviews.llvm.org/rG79de8f8441d).

* flang gained a parser for OpenACC 3.0.
[0a90ffa](https://reviews.llvm.org/rG0a90ffa7729).

* The "xunit" result formatter was removed from LLDB's testing infrastructure.
[a580376](https://reviews.llvm.org/rGa5803765d8e).