[llvm-dev] LLVM Weekly - #339, June 29th 2020

Mon Jun 29 11:51:22 PDT 2020

LLVM Weekly - #339, June 29th 2020
==================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/339>.

Welcome to the three hundred and thirty-ninth 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 call for papers for the LLVM-HPC2020 workshop [is now
open](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142631.html). The
submission deadline is September 1st, and the workshop will take place on
November 16th.

LLVM 10.0.1-rc2 [has been
tagged](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142833.html).

The development version of GCC has now [changed the default C++ dealect to
C++17](https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=0801f419440c14f6772b28f763ad7d40f7f7a580).

## On the mailing lists

* Teresa Johnson posted an RFC for [a sanitizer-based heap
profiler](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142744.html),
noting particularly the proposed refactoring sanitizer shadow setup code.

* Nathan James shared an RFC on [adding support for plugin modules to
clang-tidy](http://lists.llvm.org/pipermail/cfe-dev/2020-June/065981.html).

* Last week's [note about the need for someone to take over Phabricator
maintenance](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142458.html)
or to move to GitHub PRs has seen much more follow-up discussion.

* Alexey Bader proposed [re-using OpenCL address space attributes for
SYCL](http://lists.llvm.org/pipermail/cfe-dev/2020-June/066047.html).

* Michael Kruse proposes [introducing compiled regression tests for IR
passes](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142677.html),
aiming to combine the advantages of the current regression tests in llvm/test
an the unittests in llvm/unittests. Much of the ensuing discussion is about
clarifying the perceived limitations of FileCheck-based tests.

* Gábor Márton posted an RFC on [the future of
StdLibraryFunctionsChecker](http://lists.llvm.org/pipermail/cfe-dev/2020-June/066017.html),
seeking feedback on how to handle cases where it overlaps with other checkers
(e.g. MallocChecker, CStringModeling which could also handle argument
constraints).

* Louis Dionne is [seeking a mechanism for importing a declaration only when
it exists](http://lists.llvm.org/pipermail/cfe-dev/2020-June/066038.html).
This is motivated by porting libc++ to other platforms, which often results in
new ifdefs to conditionally exclude some declarations.

* Ammar Ben Khadra introduced [bcov, and open-source binary-level coverage
analysis
tool](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142821.html).

* Johannes Doerfert provided on [update on the revisiting llvm.assume
thread](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142831.html),
noting that the most commonly generated assume has now been moved to the
bundle representation.

* Guillame Chatelet returned to the RFC on small bitfield utilities to
[collect feedback on three possibly
syntaxes](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142662.html).

* Stella Laurenzo requested that [mlir-npcomp be accepted into LLVM as an
incubator
project](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142649.html).
mlir-npcomp is an MLIR based numpy compiler. There are many positive
responses, with most discussion about pinning down the details of the
incubator process.

* The [10th MLIR
Newsletter](https://llvm.discourse.group/t/mlir-news-10th-edition-6-26-2020/1242)
is now available, highlighting work such as an RFC on async/await, a proposed
MLIR test case reduction tool, and much more.

* Hal Finkel [shared notes from the last alias analysis technical
call](http://lists.llvm.org/pipermail/llvm-dev/2020-June/142700.html) as well
as a pool for finding a new regular time.

* Sameed A. Pervaiz queried [the extent to which llvm-libc math.h targets
speed vs
accuracy](http://lists.llvm.org/pipermail/libc-dev/2020-June/000193.html). The
respondents so far suggest accuracy as a starting goal.

## LLVM commits

* An optional pre-push hook is now available, which for now will warn about
noisy arcanist tags. [a61c73d](https://reviews.llvm.org/rGa61c73dbe32).

* Initial MC layer support for the experimental RISC-V V (vector) instruction
set extension has landed. [66da87d](https://reviews.llvm.org/rG66da87dcbaf).

* The MSP430 backend gained some basic support for debug information.
[a5bd75a](https://reviews.llvm.org/rGa5bd75aab86).

* Work has started to define OpenMP common declarations in tablegen to share
common parts between different frontends.
[d90443b](https://reviews.llvm.org/rGd90443b1d93).

* The AVR backend now supports decoding more instructions.
[01c2209](https://reviews.llvm.org/rG01c2209d518),
[ec9efb8](https://reviews.llvm.org/rGec9efb856c6),
[9f09c29](https://reviews.llvm.org/rG9f09c29f015),
[eac4a60](https://reviews.llvm.org/rGeac4a601548).

* A new AssertAlign ISD node was introduced.
[b1360ca](https://reviews.llvm.org/rGb1360caa823).

* The implementation of the AVR calling convention was rewritten.
[b9c26a9](https://reviews.llvm.org/rGb9c26a9cfe5).

* Alignment assumptions are now encoded using operand bundles.
[c95ffad](https://reviews.llvm.org/rGc95ffadb247).

## Clang commits

* `-ast-dump-decl-types` was added to include type of value and type
declarations in AST dumps. [e135cf8](https://reviews.llvm.org/rGe135cf8a03b).

* Clang toolchain support for the VE target was added, allowing the
compilation of C code for this target.
[96d4ccf](https://reviews.llvm.org/rG96d4ccf00c8).

* A dockerized testing environment was added for the Static Analyzer.
[e010d14](https://reviews.llvm.org/rGe010d1432fa),
[3770f5c](https://reviews.llvm.org/rG3770f5c9b98).

## Other project commits

* LLDB patches have started to landed to prepare for the recently announced
Apple Silicon, e.g. initial support for spawning a different debugserver for
translated processes. [fd19ddb](https://reviews.llvm.org/rGfd19ddb8f2a).

* New `check-debuginfo-*` CMake targets were added.
[ac567ee](https://reviews.llvm.org/rGac567eec119).

* The libcxx build system was updated to remove support for building through
llvm-config. [8bc62db](https://reviews.llvm.org/rG8bc62db2724).