LLVM Project News and Details from the Trenches

Monday, February 9, 2015

LLVM Weekly - #58, Feb 9th 2015

Welcome to the fifty-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. 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@asbradbury.org, or @llvmweekly or @asbradbury on Twitter.

The canonical home for this issue can be found here at llvmweekly.org.

News and articles from around the web

The Red Hat developer blog has a post about the plan to change the G++ ABI along with GCC 5. This is required for full C++11 compatibility. Unlike the last ABI change where the libstdc++ soname was changed, it will stay the same and instead different mangled names will be used for symbols.

Quarks lab have a tutorial on how to add a simple obfuscation pass to LLVM.

On the mailing lists

LLVM commits

  • A straight-line strength reduction pass has been introduced. This is intended to simplify statements that are generated after loop unrolling. It is enabled only for NVPTX for the time being. r228016.

  • A MachineInstruction pass that converts stack-relative moves of function arguments to use the X86 push instruction. This is only enabled when optimising for code size. r227752.

  • The BasicAA will now try to disambiguate GetElementPtr through arrays of structs into different fields. r228498.

  • Work on improving support in LLVM for GC continues, with the addition of a pass for inserting safepoints into arbitrary IR. r228090.

  • (Very) minimal support for the newly announced ARM Cortex-A72 landed. For now, the A72 is modeled as an A57. r228140.

  • A new heuristic has been added for complete loop unrolling, which looks at what loads might be made constant if the loop is completely unrolled. r228265.

  • A pass to exploit PowerPC's pre-increment load/store support has been added. r228328.

  • A platform-independent interface to a PDB reader has landed. r228428.

  • LLVM learnt to recognise masked gather and scatter intrinsics. r228521.

Clang commits

  • Clang learnt the 'novtable' attribute (for MS ABI support). r227796, r227838.

  • New functionality has been added for thread safety analysis, before/after annotations can now be used on mutexes. r227997.

Other project commits

  • A whole bunch of work on LLDB with multithreaded applications on Linux has landed. r227909, r227912, r227913, and more.

  • The default Polly build is now completely free of GPL dependencies. The isl and imath dependencies have been imported into the codebase to make it easier to build with a known-good revision. r228193.

No comments:

Post a Comment