LLVM Weekly - #242, August 20th 2018
Welcome to the two hundred and forty-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
Bekket McClane has authored part 2 of his tutorial on writing an LLVM pass in 2018.
On the mailing lists
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Further GSoC reports were published this week. Piotr Padlewski summarized work on devirtualization v2. Alexander Polyakov worked on re-implementing lldb-mi on top of the LLDB public API. Paul Semel worked on making LLVM binutils equivalents command-line compatible. Réka Nikolett Kovács worked on a Clang Static Analyzer checker for dangling string pointers in C++. Mikhail Ramalho worked on bug validation in the Clang Static Analyzer using the Z3 SMT solver.
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Artyom is proposing to merge an m68k codegen target upstream. Respondents to the thread suggest it would be worth splitting up to smaller patches for easier review.
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James Henderson has proposed syntax for FileCheck numeric variables and expressions.
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John Brawn has shared an RFC on delaying phi-to-select transformation until later in the pass pipeline.
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Louis Dionne suggests setting up a dedicated mailing list for libc++ rather than using cfe-dev. Responses are positive so far.
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Fabien Giesen has a very detailed response to a question about static branch prediction.
LLVM commits
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Support was added for generating DWARF debug information for labels. r340039.
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A new API was added exposing a 'CFG update struct', allowing passes or analysis to access a CFG snapshot. r339689.
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The memory management strategy for MachineMemOperand pointers attached to MachineSDNodes was modified. r339740.
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A C API was added for llvm::Error. r339802.
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The MS Demangler learned to demangle string literals. r339892.
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The lowering of UMULO (unsigned multiply with overflow) has been improved. r339922.
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The AArch64 backend gained the ability to generate pointer authentication instructions. r340018.
Clang commits
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The new AArch64 clang option
-msign-return-addressenables return address signing. r340019. -
New rotate builtins were introduced. r340141.