[llvm-dev] LLVM Weekly - #410, November 8th 2021

[Alex Bradbury via llvm-dev]

LLVM Weekly - #410, November 8th 2021
=====================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/410>.

Welcome to the four hundred and tenth 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

Sylvestre Ledru writes on the LLVM blog about [moving apt.llvm.org from a
physical server to the
cloud](https://blog.llvm.org/posts/2021-11-02-apt.llvm.org-moving-from-physical-server-to-the-cloud/).

Alex Denisov blogged about ['how to learn compilers: LLVM
edition'](https://lowlevelbits.org/how-to-learn-compilers-llvm-edition/),
which includes a shout-out to LLVM Weekly as "the single newsletter I am aware
of that doesn't have ads".

More videos from CppCon 2021 [are now
available](https://pages.jetbrains.com/cppcon2021).


## On the mailing lists

* Haojian Wu shared an RFC on [contributing a C++ 'pseudo-parser' for use by
  clang
  tooling](https://lists.llvm.org/pipermail/cfe-dev/2021-November/069246.html).
  This 'pseudo-parser' would be able to parse broken code, would resolve
  ambiguities using heuristics, and is intended to be fast. Sam McCall
  [provided answers to some initial
  questions](https://lists.llvm.org/pipermail/cfe-dev/2021-November/069254.html),
  noting in  measurements that showed tree-sitter achieves ~95% average
  accuracy on a large codebase in response to concerns about feasibility.

* Maksim Panchenko posted about [preparing BOLT for the LLVM
  monorepo](https://lists.llvm.org/pipermail/llvm-dev/2021-November/153551.html),
  seeking input on the proposed next steps.

* Simon Moll
  [proposed](https://lists.llvm.org/pipermail/llvm-dev/2021-November/153571.html)
  making the VE target 'fficial' (graduating from 'experimental').

* Amara Emerson wrote to [highlight patches to introduce
  llvm-bisectd](https://lists.llvm.org/pipermail/llvm-dev/2021-November/153548.html),
  a tool to more rapidly bisect miscompiles by running in parallel.

* Serge Guelton posted a [response to the 'Trojan Source'
  CVE](https://lists.llvm.org/pipermail/llvm-dev/2021-November/153529.html),
  which also linked to the [now-public disclosure
  thread](https://bugs.chromium.org/p/llvm/issues/detail?id=11).

* Ahmed Bougacha [followed
  up](https://lists.llvm.org/pipermail/llvm-dev/2021-November/153523.html) to
  the thread on pointer authentication for arm64e to note patches are now up
  for review.

* Anton Korobeynikov provided [another update on the Bugzilla to GitHub issues
  migration](https://lists.llvm.org/pipermail/llvm-dev/2021-November/153514.html).
  Unfortunately there were some problems in the 'dry-run' migration that will
  require input from GitHub to resolve.

* ORC JIT Weekly #43 [is
  out](https://lists.llvm.org/pipermail/llvm-dev/2021-November/153606.html).


## LLVM commits

* The llvm-reduce tool can now operate on MIR (though for now, only a single
  machine function). [fd41738](https://reviews.llvm.org/rGfd41738e2ca9).

* Initial codegen infrastructure was committed for the CSKY target.
  [cf78715](https://reviews.llvm.org/rGcf78715cae72).

* The -print-changed=dot-cfg and -print-changed=dot-cfg-quiet option were
  added, which export a HTML page with DOT files showing colourized changes.
  [816761f](https://reviews.llvm.org/rG816761f04484).

* The existence of the `llvm/utils/update_*` scripts was documented.
  [2a7c3f8](https://reviews.llvm.org/rG2a7c3f8b02bf).

* Hex string parsing in StringExtras.h was simplified in order to run faster
  when LLVM/Clang is built in debug mode.
  [2fcffcd](https://reviews.llvm.org/rG2fcffcd0e8e5).

* The llvm.vp.load, llvm.vp.store, llp.vp.gather, and llvm.vp.scatter
  intrinsics were documented.
  [93e1802](https://reviews.llvm.org/rG93e1802af332),
  [3a11fb57](https://reviews.llvm.org/rG3a11fb572cf5).

* Support was added for the RISC-V Zfhmin extension.
  [5c3d718](https://reviews.llvm.org/rG5c3d7184b435).


## Clang commits

* The patch to rename `enable-noundef-analysis` to `disable-undef-analysis`
  and turn it off by default was committed again.
  [aacfbb9](https://reviews.llvm.org/rGaacfbb953eb7).

* A new clang-tidy check was added for CERT rule ERR33-C.
  [4bcbb3d](https://reviews.llvm.org/rG4bcbb3d4d7a8).

* `__builtin_reduce_max` and `__builtin_reduce_min` builtins were added.
  [7999355](https://reviews.llvm.org/rG7999355106fb).


## Other project commits

* LLVM's libc gained implementations of strndup, stpcpy, and stpncpy.
  [3bbbec1a](https://reviews.llvm.org/rG3bbbec1ae7b7),
  [9b6f8b9](https://reviews.llvm.org/rG9b6f8b985c6a).

* A Bazel build file was added for the MLIR Python bindings.
  [b1a3022](https://reviews.llvm.org/rGb1a302265bf8).