[llvm-dev] LLVM Weekly - #294, August 19th 2019

[Alex Bradbury via llvm-dev]

LLVM Weekly - #294, August 19th 2019
====================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/294>.

Welcome to the two hundred and ninety-fourth 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](https://www.linkedin.com/in/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 at asbradbury.org>, or
@llvmweekly or @asbradbury on Twitter.


## News and articles from around the web

LLVM 9.0.0-rc2 [has been
tagged](http://lists.llvm.org/pipermail/llvm-dev/2019-August/134553.html).


## On the mailing lists

* Gary Elsesser [started a
discussion](http://lists.llvm.org/pipermail/llvm-dev/2019-August/134562.html)
on options for better supporting multidimensional array references, inspired
by MLIR, with the most ambitious option being to adopt MLIR in LLVM. Chris
Lattner [expressed
interest](http://lists.llvm.org/pipermail/llvm-dev/2019-August/134576.html) in
the proposed second option to "Create a middle-LLVM that works on MLIR; do all
loop restructuring here; phase out existing LLVM loop restructuring."

* JF Bastien reports Clang and LLVM [are now using
C++14](http://lists.llvm.org/pipermail/llvm-dev/2019-August/134577.html).

* Ismail Bennani is interning at Apple and [working on Fast Conditional
Breakpoints](http://lists.llvm.org/pipermail/lldb-dev/2019-August/015370.html).
This RFC explains the high level design as well as full implementation
details. Ismail has already submitted initial patches, and is keen for
feedback.

* Michael Spencer shares an RFC on [C++20 modules dependency
discovery](http://lists.llvm.org/pipermail/cfe-dev/2019-August/063072.html) in
Clang.

* In response to a question about building a subset of LLVM source files with
debug info, Mark de Wever [provides a handy CMake
tip](http://lists.llvm.org/pipermail/llvm-dev/2019-August/134606.html).

* Paolo Savini is [seeking advice on selecting instructions from the proposed
RISC-V bit manipulation
extension](http://lists.llvm.org/pipermail/llvm-dev/2019-August/134555.html),
especially when input might be implemented using a loop. Tim Northover [points
to](http://lists.llvm.org/pipermail/llvm-dev/2019-August/134556.html)
LoopIdiomRecognize.cpp.

* Bardia Mahjour shared [minutes from the Aug 14th Loop Opt working group
meeting](http://lists.llvm.org/pipermail/llvm-dev/2019-August/134561.html).

* Cyndy Ishida is [working on continuing TextAPI support for
MachO](http://lists.llvm.org/pipermail/llvm-dev/2019-August/134529.html), and
points to some recently submitted patches.

* lldb-mi [has now
moved](http://lists.llvm.org/pipermail/lldb-dev/2019-August/015357.html) to
its own GitHub repository. The project is also seeking a maintainer.

* Arem Dergachev
[proposes](http://lists.llvm.org/pipermail/cfe-dev/2019-August/063092.html)
routing clang-tidy diagnostics through the Static Analyzer diagnostic engine,
as a stepping stone towards allowing the Staic Analyzer to expose clang-tidy
checks as its own.


## LLVM commits

* All uses of `llvm::make_unique` have been migrated to the C++14
`std::make_unique`. [r369013](https://reviews.llvm.org/rL369013).

* A proposal for a libc project under the LLVM umbrella was committed.
[r369012](https://reviews.llvm.org/rL369012).

* A new style of coroutine lowering was added, "returned-continuation
lowering" which complements the alternative "switched-resume lowering". See
the commit message and added documentation for a thorough description of the
differences. [r368788](https://reviews.llvm.org/rL368788).

* An optimised lowering for `X % C == 0` was introduced, based on a
description in Hacker's Delight. [r368702](https://reviews.llvm.org/rL368702).

* The GlobalISel InstructionSelector instance is now non-const, allowing state
to be maintained. [r368652](https://reviews.llvm.org/rL368652).

* The LLVM codebase is now ready for C++14, as the minimum required
Gcc/Clang/MSVC has been bumped. [r368799](https://reviews.llvm.org/rL368799).

* The bugpoint redesign work continues, with the addition of a pass to remove
global variables. [r369061](https://reviews.llvm.org/rL369061).


## Clang commits

* clang-docs generated HTML files were redesigned.
[r369139](https://reviews.llvm.org/rL369139).

* The Static Analyzer now understands a new silence-checkers analyzer-config,
which of course silences the listed checkers.
[r369078](https://reviews.llvm.org/rL369078).


## Other project commits

* LLDB now uses LLVM's debug line parser rather than its own.
[r368742](https://reviews.llvm.org/rL368742).

* LLDB gained initial support for native debugging of x86/x64 Windows
processes. [r368759](https://reviews.llvm.org/rL368759).

* GWP-ASan gained support for stack frame compression, reducing the memory
conceumption of stack traces by up to 50%.
[r369048](https://reviews.llvm.org/rL369048).

* The Wasm linker now allows linking of pic code into static binaries.
[r368719](https://reviews.llvm.org/rL368719).