Alex Bradbury via llvm-dev
2020-Aug-03 19:01 UTC
[llvm-dev] LLVM Weekly - #344, August 3rd 2020
LLVM Weekly - #344, August 3rd 2020 ================================== If you prefer, you can read a HTML version of this email at <http://llvmweekly.org/issue/344>. Welcome to the three hundred and forty-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 11.0.0-rc1 [has been tagged](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143839.html). The 2020 Linux Plumbers Conference [will feature an LLVM microconference](https://www.linuxplumbersconf.org/blog/2020/llvm-microconference-accepted-into-2020-linux-plumbers-conference/). ## On the mailing lists * Andrzej Warzynski [shares a new clang tutorial](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143908.html). [clang-tutor](https://github.com/banach-space/clang-tutor) provides a collection of out-of-tree plugins for Clang with the intent to making it easier for people to get started developing plugins. * Andrzej Warzynski posted an RFC on [refactoring libclangDriver/libclangFrontend to share with Flang](http://lists.llvm.org/pipermail/cfe-dev/2020-July/066393.html). * Stephen Neuendorffer sent a heads-up that [you may need to manually 'unwatch' the llvm/circt repo](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143925.html) if you're a member of the LLVM org. * Johannes Doerfert proposed [adding support for heterogeneous LLVM-IR modules](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143808.html). * Petr Hosek shared [challenges he's facing related to the recent change in ld.bfd tombstone behaviour](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143920.html) with suggestions for handling changes like this in the future. * ORC JIT Weekly #18 [reports on the addition of the TargetProcessControl API](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143804.html). * "AE" asked about [filesystem support in libcxx on Windows](http://lists.llvm.org/pipermail/libcxx-dev/2020-July/000899.html). Stephan T. Lavavej [volunteered to contribute Microsoft's implementation to libcxx](http://lists.llvm.org/pipermail/libcxx-dev/2020-July/000900.html). * Zachary Turner enquired about the [status of the LLVM re-licensing effort](http://lists.llvm.org/pipermail/llvm-foundation/2020-July/000213.html). Hal Finkel [reports](http://lists.llvm.org/pipermail/llvm-foundation/2020-July/000216.html) that it is still in progress and the January 2019 target date will be revised soon. * Craig Topper raised the issue of [SimplifyCFG hoisting fences in if/else branches](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143858.html), and how this may harm attempts to use these fences to mitigate speculative execution vulnerabilities. * Son Tuan VU kicked off a [discussion on maintaining metadata other than debug info through compilation](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143639.html). This triggered thoughts from others, [e.g. Lorenzo Casalino](http://lists.llvm.org/pipermail/llvm-dev/2020-July/143869.html). ## LLVM commits * llvm-jitlink gained a new `-harness` option to enhance testing. [8ce8cee](https://reviews.llvm.org/rG8ce8cee1e1d). * RISC-V Vector MC layer support was updated to bring it in line with the v0.9 draft specification. [47a4a27](https://reviews.llvm.org/rG47a4a27f472). * The XRay infrastructure can now be used for runtime recursion detection. [f2ab213](https://reviews.llvm.org/rGf2ab2134c7c). * llvm-exegesis learned to use `LBR` for more precise measurements on Skylake and onwards. [ee7caa7](https://reviews.llvm.org/rGee7caa75939). * Support was removed from the PowerPC backend for the IBM BG/Q supercomputer. [adffce7](https://reviews.llvm.org/rGadffce71538). * The TableGen GlobalISelEmitter now allows output instructions with multiple defs. [ee3feef](https://reviews.llvm.org/rGee3feef5aaa). * File lock/unlock functions were added to LLVM's support library. [5367369](https://reviews.llvm.org/rG536736995bf), [032ed39](https://reviews.llvm.org/rG032ed39defc). * The X86CondBrFolding pass was removed due to correctness issues. [e1dd212](https://reviews.llvm.org/rGe1dd212c874). * FileCheck `-dump-input` was extended with substitutions, and FileCheck will now report captured variables in input dumps and traces. [d680711](https://reviews.llvm.org/rGd680711b94e), [9f86b8e](https://reviews.llvm.org/rG9f86b8ec41f). * The CastContextHint enum was added to getCastInstrCost (e.g. Normal, Masked, GatherScatter, etc). [60280e9](https://reviews.llvm.org/rG60280e9818a). ## Clang commits * Clang's coverage support was fixed to not count lines containing only comments.[b46176b](https://reviews.llvm.org/rGb46176bbb09). * Support for the OpenMP 'present' motion modifier was added to Clang. [9f2f3b9](https://reviews.llvm.org/rG9f2f3b9de63). ## Other project commits * The dataflow sanitizer gained an efficient "fast16labels" instrumentation mode, for use when the user needs no more than 16 labels. [e2d0b44](https://reviews.llvm.org/rGe2d0b44a7cd). * A WrapperGen tool was added to LLVM's libc implementation, to generate C wrappers for the C++ LLVM libc implementation.s [a32af82](https://reviews.llvm.org/rGa32af8252fd). * The LLD ELF linker's CallGraphSort was ported to the COFF linker. [763671f](https://reviews.llvm.org/rG763671f387f). * Support for mutable types was added to MLIR. [a518299](https://reviews.llvm.org/rGa51829913db).