[LLVMdev] LLVM Weekly - #83, Aug 3rd 2015

Alex Bradbury asb at asbradbury.org
Mon Aug 3 06:19:20 PDT 2015

LLVM Weekly - #83, Aug 3rd 2015

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Welcome to the eighty-third 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

The CodeChecker static analysis infrastructure built on Clang Static Analyzer
[has been released](https://github.com/Ericsson/codechecker). The
from the talk at EuroLLVM earlier this year give a good overview.

LLVM/Clang 3.7 RC2 [has been
tagged](http://article.gmane.org/gmane.comp.compilers.clang.devel/44237). Time
to get testing.

The implementation of the [Picon](https://github.com/anssi-fr/picon) Control
Flow Integrity protection mechanism has been released. See also the associated
paper [Picon: Control Flow Integrity on LLVM

## On the mailing lists

* There is a plan to [jump to Windows 7 as the baseline requirement for
LLVM](http://article.gmane.org/gmane.comp.compilers.llvm.devel/88947), which
has been featured in LLVM Weekly previously many months ago. If such a move
would cause a problem for you, now is the time to speak up. There's also a
proposal to [drop support for the old mingw.org
toolchains](http://article.gmane.org/gmane.comp.compilers.llvm.devel/88959) in
favour of the maintained mingw-w64.

* James Molloy has prototyped [LoopEditor](http://reviews.llvm.org/D11530), a
high-level API for loop transformations in LLVM and is [seeking additional
feedback](http://article.gmane.org/gmane.comp.compilers.llvm.cvs/260989). The
hope is that existing loop transformations could be rewritten and simplified
to use it.

* Easwaran Raman has shared an [RFC on speedup estimation for inlining cost
analysis](http://article.gmane.org/gmane.comp.compilers.llvm.devel/88929). The
idea is that the estimated speedup (reduction in dynamic instruction count)
from performing the inlining should be used as part of the cost metric.

* Chris Bieneman has penned a [CMake in LLVM
roadmap](http://article.gmane.org/gmane.comp.compilers.llvm.devel/88859) and
[July CMake
There's even [hope the autoconf build system might be marked deprecated before
the 3.8

* Peter Collingbourne has shared a [proposal for arbitrary relocations in
constant global

* Try not to panic, but the LLVM mailing lists [will be down on August
4th](http://article.gmane.org/gmane.comp.compilers.llvm.devel/88811) as they
will be moving off the UIUC servers. Additionally, SVN access will be
read-only and the LLVM bugzilla will be down.

* Mehdi Amini has issued a [helpful notice for out-of-tree
on the removal of RegisterScheduler::setDefault.

* Lang Hames has written a [whirlwind introduction to implementing lazy
JITting support for a new architecture in

* Michael Schlottke-Lakemper kicked off a discussion on the possibility of
[using lldb.so to create a stack
Respondents pointed out a number of possible choices, including using the
`llvm::sys::printStackTrace()` function.

## LLVM commits

* A new exception handling representation has been introduced for MSVC
compatibility. The commit includes the appropriate updates to the LLVM
language reference. [r243766](http://reviews.llvm.org/rL243766).

* A test to check bitcode compatibility has been added. This will help ensure
the bitcode format produced by an X.Y release is readable by the following X.Z
releases. [r243779](http://reviews.llvm.org/rL243779).

* The lli documentation has been updated and now better explains its purpose.

* LLVM gained a target-independent thread local storage (TLS) implementation.

* A `reverse(ContainerTy)` range adapter was added.

## Clang commits

* The method for emitting metadata for loop hint pragmas has been modified,
using CGLoopInfo. [r243315](http://reviews.llvm.org/rL243315).

* Clang learned to pass `-Wa,-mfpu`, `-Wa,-mhwdiv`, and `-Wa,-mcpu` to the
integrated assembler. [r243353](http://reviews.llvm.org/rL243353).

* Initial support for Open MP 4.1's extended ordered clause was added.

## Other project commits

* lldb is starting to gain support for indicating when you are debugging a
function that has been optimized. [r243508](http://reviews.llvm.org/rL243508).

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