[llvm-dev] LLVM Weekly - #175, May 8th 2017

[Alex Bradbury via llvm-dev]

LLVM Weekly - #175, May 8th 2017
================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/175>.

Welcome to the one hundred and seventy-fifth 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](http://asbradbury.org). 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

LLVM 4.0.1-rc1 [has been
tagged](http://lists.llvm.org/pipermail/llvm-dev/2017-May/112573.html).

Azul have [announced](https://www.azul.com/press_release/falcon-jit-compiler/)
Falcon, their new LLVM-based JVM JIT. Gil Gene, CTO and co-founder of Azul
[wrote a little more about it
here](stuff-gil-says.blogspot.com/2017/05/zing-hits-trifecta.html).

GCC 7.1 [has been released](https://gcc.gnu.org/ml/gcc/2017-05/msg00017.html).


## On the mailing lists

* Nicholas Wilson started a thread aiming to [revive efforts to get a SPIR-V
backend upstream in
LLVM](http://lists.llvm.org/pipermail/llvm-dev/2017-May/112538.html). Tom
Stellard has given a good summary of his [reasoning for why SPIR-V might be
better off not using
SelectionDAG/GlobalISel](http://lists.llvm.org/pipermail/llvm-dev/2017-May/112651.html).

* Kamil Rytarowski has shared an [update on LLDB/NetBSD progress through
April](http://lists.llvm.org/pipermail/lldb-dev/2017-May/012352.html).

* Perry E. Metzger is curious if there is enough [interest to support a new
frontend developer focused mailing
list](http://lists.llvm.org/pipermail/llvm-dev/2017-May/112730.html).

* David Blaikie has detailed [current issues with DWARF fission and
LTO](http://lists.llvm.org/pipermail/llvm-dev/2017-May/112654.htm).

* Kit Barton has shared an RFC on [extending shrink
wrapping](http://lists.llvm.org/pipermail/llvm-dev/2017-May/112623.html), with
the aim of improving the location of save and restore code for callee-saved
registers. He is looking for feedback on the shrink wrapping approach vs
enabling SplitCSR for PowerPC. SplitCSR is probably best described in its
[initial review](https://reviews.llvm.org/D15340).


## LLVM commits

* ADDCARY and SUBCARRY ISDOpcodes have been introduced, to replace ADDC/SUBC.
[r301775](http://reviews.llvm.org/rL301775).

* The AArch64AddressTypePromotion pass has been removed, as the necessary
transformations can now be performed by CodeGenPrepare.
[r302245](http://reviews.llvm.org/rL302245).

* llvm-dwarfdump gained a `--verify` option, which will perform a number of
checks on the input file's DWARF info.
[r301844](http://reviews.llvm.org/rL301844).

* Support has been added for AMD's lightweight profiling instructions.
[r302041](http://reviews.llvm.org/rL302041).


## Clang commits

* Documentation has been added for clangd, the Clang-based implementation of
the "Language Server Protocol". [r302191](http://reviews.llvm.org/rL302191).

* The SanitizerCoverage documentation has been updated to better describe its
current state. [r301888](http://reviews.llvm.org/rL301888).

* `#pragma clang module begin/end` has been introduced. They simulate the
effect of entering or leaving a file with an associated module.
[r302098](http://reviews.llvm.org/rL302098).


## Other project commits

* The scudo secure allocator can now be used on Android.
[r302300](http://reviews.llvm.org/rL302300).

* libcxx gained new macros for dylib availability. These are used to enable a
binary to be compiled that is inteded to be employed on an older macOS/iOS
platform. [r302172](http://reviews.llvm.org/rL302172).