[LLVMdev] LLVM Weekly - #57, Feb 2nd 2015

[Alex Bradbury]

LLVM Weekly - #57, Feb 2nd 2015
===============================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/57>.

Welcome to the fifty-seventh 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.

I've been at FOSDEM this weekend in Brussels (which is why this week's issue
is perhaps a little shorter than usual!). Most talks were recorded and I'll be
linking to the videos from the LLVM devroom once they're up. For those
interested, you can [see the slides from my lowRISC talk
here](https://speakerdeck.com/asb/lowrisc-the-path-to-an-open-source-soc). If
you want to chat about the project, you may want to join #lowRISC on
irc.oftc.net.


## News and articles from around the web

Eli Bendersky has written a useful [introduction to using the llvmlite Python
to LLVM
binding](http://eli.thegreenplace.net/2015/building-and-using-llvmlite-a-basic-example/),
which was borne out of the Numba project.

LLVM/Clang 3.6-rc2 [has been
tagged](http://article.gmane.org/gmane.comp.compilers.llvm.devel/81600) and is
ready for testing.

The next LLVM bay-area social is taking place [on Feb 5th at
7pm](http://article.gmane.org/gmane.comp.compilers.clang.devel/41012/).

The EuroLLVM [call for
papers](http://article.gmane.org/gmane.comp.debugging.lldb.devel/6413/) closes
on Feb 16th.


## On the mailing lists

* David Majneer has attempted to describe the often confusing 'poison'
semantics for LLVM, and [submitted an
RFC](http://article.gmane.org/gmane.comp.compilers.llvm.devel/81383). Masses
of discussion follows.

* Dylan McKay has been working on an LLVM backend for AVR and has come to the
mailing list with two questions on instruction encoding in the last week.
They're interesting questions with useful answers - [how to modify the
encoding based on target
features](http://article.gmane.org/gmane.comp.compilers.llvm.devel/81531) and
[how to encode instructions with inconsistent
formats](http://article.gmane.org/gmane.comp.compilers.llvm.devel/81613/).

* Saleem Abdulrasool [kicked off a long discussion on where libunwind should
live](http://article.gmane.org/gmane.comp.compilers.llvm.devel/81577).

* Andrew Kaylor has posted an [RFC on adding support for native windows C++
exception
handling](http://article.gmane.org/gmane.comp.compilers.llvm.devel/81284).

* Matt Arsenault has posted an [RFC on adding and ISD node for fused multiply
add
operations](http://article.gmane.org/gmane.comp.compilers.llvm.devel/81443).

* A question about the [meaning of
RAUW](http://article.gmane.org/gmane.comp.compilers.llvm.devel/81323) is a
good opportunity to highlight the existence of the very handy [LLVM
lexicon](http://llvm.org/docs/Lexicon.html).


## LLVM commits

* A simple in-process fuzzer was added to LLVM.
[r227252](http://reviews.llvm.org/rL227252).

* The programmer's manual gained a section about type hierarchies,
polymorphism, and virtual dispatch.
[r227292](http://reviews.llvm.org/rL227292).

* The upstreaming of Sony's patches for their PS4 compiler started with the
addition of the PS4 target triple.
[r227060](http://reviews.llvm.org/rL227060).

* DataLayout now lives again in the TargetMachine rather than the
TargetSubtagertInfo. [r227113](http://reviews.llvm.org/rL227113).

* RuntimeDyld learned to support weak symbols.
[r227228](http://reviews.llvm.org/rL227228).

* LLVM gained a new tool, llvm-pdbdump to dump the contents of Microsoft PDB
('Program DataBase') files, including debug tables.
[r227241](http://reviews.llvm.org/rL227241),
[r227257](http://reviews.llvm.org/rL227257).

* The loop vectorizer now supports an arbitrary constant step for its
induction variables, rather than just -1 or +1.
[r227557](http://reviews.llvm.org/rL227557).


## Clang commits

* The clang-format-fuzzer tool was added, which builds on the LLVM fuzzer lib.
[r227354](http://reviews.llvm.org/rL227354).

* MS ABI work continues with proper support for setjmp.
[r227426](http://reviews.llvm.org/rL227426).

* Clang started to learn about the PS4 target triple.
[r227194](http://reviews.llvm.org/rL227194).


## Other project commits

* The PowerPC ELF target was dropped from lld.
[r227320](http://reviews.llvm.org/rL227320).