[llvm-dev] LLVM Weekly - #214, Feb 5th 2018

[Alex Bradbury via llvm-dev]

LLVM Weekly - #214, Feb 5th 2018
================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/214>.

Welcome to the two hundred and fourteenth 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

Reminder: the deadline for paper submissions for [EuroLLVM
2018](http://llvm.org/devmtg/2018-04/) is this Friday, February 9th.

Adrien Guinet has released [DragonFFI](https://github.com/aguinet/dragonffi/),
a C Foreign Function Interface (FFI) library based on Clang/LLVM. It aims to
provide broader ABI support than libffi and to work around the limitations of
Python's cffi C parser through the use of Clang.


## On the mailing lists

* Fāng-ruì Sòng started a discussion on [moving the LLVM developer-facing
utility scripts to Python
3](http://lists.llvm.org/pipermail/llvm-dev/2018-January/120826.html).

* Tanya Lattner is [looking for
help](http://lists.llvm.org/pipermail/llvm-dev/2018-February/120938.html) in
fleshing out the LLVM GSoC'18 proposed projects list.

* Paul Robinson gave a [helpful
summary](http://lists.llvm.org/pipermail/llvm-dev/2018-January/120809.html) of
recent work on improving 'debuggability' of optimized code.

* George Karpenkov wrote up [short investigation of exploration strategies and
paths for Clang
analyzer](http://lists.llvm.org/pipermail/cfe-dev/2018-January/056718.html).

* Sean Perry has been looking at implementing support for `-fexec-charset` and
`-finput-charset`, and is [seeking
feedback](http://lists.llvm.org/pipermail/cfe-dev/2018-January/056721.html).


## LLVM commits

* LLVM's policies on library layering and header isolation have been
documented in the coding standards doc.
[r324004](http://reviews.llvm.org/rL324004).

* The sigil for machine IR physical registers is now `$` rather than `%`.
[r323922](http://reviews.llvm.org/rL323922).

* Support has been added to dsymutil for generating Apple accelerator tables.
[r323655](http://reviews.llvm.org/rL323655).

* `update_test_checks.py` and `update_llc_test_checks.py` have been refactored
to share common code. [r323718](http://reviews.llvm.org/rL323718).

* A scheduling model has been added for the Exynos M3.
[r323773](http://reviews.llvm.org/rL323773).

* A new extension is now supported, linker options can be passed from the
frontend to the linker through the `linker_options` section.
[r323783](http://reviews.llvm.org/rL323783).

* The X86 retpoline think insertion pass is now a machine function pass rather
than a module pass. [r323915](http://reviews.llvm.org/rL323915).

* InstCombine will now canonicalise to i8/i16/i32 operations even if the
resulting type isn't legal according to the datalayout. See the [llvm-dev
thread](http://lists.llvm.org/pipermail/llvm-dev/2018-January/120522.html) for
more justification. [r324174](http://reviews.llvm.org/rL324174).


## Clang commits

* Debug information is now generated for C99 VLA (variable-length array)
types. [r323952](http://reviews.llvm.org/rL323952).

* Partial support for CUDA-9.1 has been added to Clang.
[r323713](http://reviews.llvm.org/rL323713).

* clangd has been refactored to pass its Context object implicitly using
thread local storage. [r323872](http://reviews.llvm.org/rL323872).


## Other project commits

* As [previously announced](http://reviews.llvm.org/rL317265), a number of
experimental APIs that have been superseded by versions adopted by the C++
standard have been removed. experimental/optional, experimental/any,
experimental/numeric and experimental::sample.
[r323971](http://reviews.llvm.org/rL323917),
[r323972](http://reviews.llvm.org/rL327972),
[r323975](http://reviews.llvm.org/rL323975),
[r323979](http://reviews.llvm.org/rL323979).

* The libcxxabi demangler gained improved support for variadic templates and
seen a large refactoring. [r323906](http://reviews.llvm.org/rL323906),
[r324111](http://reviews.llvm.org/rL324111).

* New python utilities were added to make it easier to write LLDB tests for
when LLDB is acting as a client of a gdb-remote connection.
[r323636](http://reviews.llvm.org/rL323636).

* LLDB tests are now compiled out-of-tree.
[r323803](http://reviews.llvm.org/rL323803).