LLVM Weekly - #292, August 5th 2019

Welcome to the two hundred and ninety-second 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.

News and articles from around the web

LLVM 9.0.0-rc1 has been tagged.

You can find out more about the LLVM project's move to GitHub on the LLVM blog.

On the mailing lists

• Leonard Chen proposes switching to the new pass manager by default, now that 9.0 has branched.

• David Greene wrote an RFC on strong typedef utilities for LLVM, which describes utility classes intended to increase type safety within the LLVM codebase.

• A major blocker to transitioning the LLVM codebase to C++14 has now been cleared. Now that Google have migrated to libc++, the migration plan can move forwards.

• Alex L shared an RFC on improving Clang's FileManager, which right now model file entries with multiple names correctly.

• Michael Kruse queries whether LLVM can optimise based on the assumption that stack overflow is undefined behaviour, and how this might interact with the noreturn/nounwind/willreturn function attributes.

• Rui Ueyama proposes adding an LLD feature to generate a build dependency file, similar to the -MD flag for Clang and GCC.

• Bardia Mahjour shares minutes from the loop optimisation working group.

LLVM commits

• An LLVM bitstream-based remark serializer was introduced. This has two serialisation modes: separate and standalone. r367364.

• Unnamed function arguments are now printed with their automatically generated name (e.g. "i32 %0") in definitions. r367755.

• A new Alignment type was introduced to the LLVM codebase. r367393.

• APInt gained a new clearLowBits() method. r367287.

• The git-llvm helper will now ask for confirmation if it would push multiple commits. r367321.

• The AArch64 backend gained support for "tagged globals", where global variable addresses may include a pointer tag in bits 53-63. r367475.

• The raw_ostream interface was improved to allow you to "write" colours using operator<<. r367649.

Clang commits

• A new -Wimplicit-float-conversion warning was introduced. r367497.

• clang-tidy gained a new google-upgrade-googletest-case checker which updates uses of a deprecated API. r367263.

Other project commits

• libcxx gained allocator benchmarks. r367722.

• The documentation on building LLDB was updated with better coverage of the monorepo and CMake caches. r367302.