LLVM Weekly - #57, Feb 2nd 2015

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. Subscribe to future issues at https://llvmweekly.org and pass it on to anyone else you think may be interested. Please send any tips or feedback to asb@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. 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, which was borne out of the Numba project.

LLVM/Clang 3.6-rc2 has been tagged and is ready for testing.

The next LLVM bay-area social is taking place on Feb 5th at 7pm.

The EuroLLVM call for papers 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. 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 and how to encode instructions with inconsistent formats.

• Saleem Abdulrasool kicked off a long discussion on where libunwind should live.

• Andrew Kaylor has posted an RFC on adding support for native windows C++ exception handling.

• Matt Arsenault has posted an RFC on adding and ISD node for fused multiply add operations.

• A question about the meaning of RAUW is a good opportunity to highlight the existence of the very handy LLVM lexicon.

LLVM commits

• A simple in-process fuzzer was added to LLVM. r227252.

• The programmer's manual gained a section about type hierarchies, polymorphism, and virtual dispatch. r227292.

• The upstreaming of Sony's patches for their PS4 compiler started with the addition of the PS4 target triple. r227060.

• DataLayout now lives again in the TargetMachine rather than the TargetSubtagertInfo. r227113.

• RuntimeDyld learned to support weak symbols. r227228.

• LLVM gained a new tool, llvm-pdbdump to dump the contents of Microsoft PDB ('Program DataBase') files, including debug tables. r227241, r227257.

• The loop vectorizer now supports an arbitrary constant step for its induction variables, rather than just -1 or +1. r227557.

Clang commits

• The clang-format-fuzzer tool was added, which builds on the LLVM fuzzer lib. r227354.

• MS ABI work continues with proper support for setjmp. r227426.

• Clang started to learn about the PS4 target triple. r227194.

Other project commits

• The PowerPC ELF target was dropped from lld. r227320.