[llvm-dev] LLVM Weekly - #308, November 25th 2019

Alex Bradbury via llvm-dev llvm-dev at lists.llvm.org
Mon Nov 25 07:23:38 PST 2019

LLVM Weekly - #308, November 25th 2019

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Welcome to the three hundred and eighth 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

Videos from the LLVM Dev Meeting 2019
[continue to be

LLVM 9.0.1-rc1 [has been

The call for presentations for EuroLLVM 2020 [is now
The event will take place April 6-7 in Paris and proposals are due by Jan

## On the mailing lists

* Chandler Carruth kicked off a lengthy RFC thread on [moving towards Discord
for real time chat and Discourse for forum/list-style
This proposal follows discussions at the LLVM Dev Meeting and the Women in
Compilers and Tools meeting. This proposal has resulted in a large number of
responses. A number of people raised concerns about Discord as a proprietary
solution. Several respondents suggest it would be productive to separate
discussion of the real time chat and the forum solution.

* Eric Astor is [proposing to add MASM (Microsoft Macro Assembler)
to the LLVM MC layer.

* Bardia Mahjour shared [minutes from the loop optimisation working group Nov

* Sean Kilmurray posted an RFC on [adding a mock backend target to
which could be used to test assumptions like the size of bytes or addressable
unit sizes.

* David Blaikie started a
[discussion about
both from a DWARF perspective and the LLVM implementation.

## LLVM commits

* A new API was introduced to determine if an instruction can be safely moved
before another instruction. [ae8a8c2](https://reviews.llvm.org/rGae8a8c2db6c).

* Scalable vector MVT size queries are now supported.

* llvm-objdump now prints relocation addends in hexadecimal, just like GNU
objdump. [6baec97](https://reviews.llvm.org/rG6baec971271).

* Scheduling and cost models were added for the Exynos M5.

* TableGen will no longer error in the case of duplicate includes.

* The CMake build system was updated to explicitly mark libraries defined in
lib/ as "component libraries".

* The new gen-opt-rst TableGen backend will generate "command guides" for
common line options, for use in documentation.

## Clang commits

* Debug info size for Sema was reduced by adding an `anchor()` method,
resulting in a 17% saving for Sema object files on Windows and 14.6% on Linux.

* The new clang-tidy performance-no-automatic-move check will flag when
constructs prevent automatic move of local variables.

* `-ffixed-rN` can now be used to reserve r6-r11 on ARM.

* Support was added for `__attribute__((objc_direct))` and

## Other project commits

* LLVM libc now has a TableGen based header generator.

* LLDB gained a document describing caveats related to the usage of Python.

* LLDB now has some documentation on reproducers.

* The Archer tool was added to LLVM's OpenMP implementation. It provides TSan
annotations for OpenMP synchronisation.

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