Compiler Social - 05.06.25

Date: 5 June 2025
Time: 15:00-20:00 (1 talk followed by socializing)
Location: William Gates Building, 15 JJ Thomson Ave, Cambridge CB3 0FD
Rooms: LT1 (Talks), The Street (Social)
Hosts: Emma Urquhart, Luisa Cicolini, Tobias Grosser

⮕ Register Here

Join us for a relaxed chat about compilers, while socializing over refreshments. Our social is open to students, academics, professional developers and really anyone interested in compilation. We welcome beginners as well as experts. Our social is an unguided space offered for you to get to know people, try out some new ideas, get feedback on your code, or pair-program on a difficult program. Come with just a paper notebook or bring your laptop to hack on some in-progress patches.

This social is traditionally organized by the LLVM community, but is open to all (potential) compiler enthusiasts.

Translation Validation for LLVM's AArch64 Backend

Alive2 is a practical oracle for determining whether a transformation on LLVM IR is a refinement -- that is, whether it is valid under the rules for LLVM optimizations. In this talk I'll describe an analogous translation validation solution for LLVM's AArch64 backend that we've used to find 42 miscompilation bugs, many of which were in architecture-neutral code and hence could have also affected other backends. Our tool, arm-tv, reuses Alive2 as a source of LLVM semantics and offers a choice of two AArch64 semantics, one that we wrote by hand and the other derived from ARM's machine readable specification of their ISA.

John Regehr is a computer science professor at the University of Utah, USA. He liked to build tools for compiler developers to use, and then write papers about them.

History

The LLVM Compiler Social Cambridge has a long history. Over the years it was by members of the LLVM community in local pubs, at Microsoft Research, Graphcore and in many other venues. Similar events are hosted in the Bay Area, Paris, Zurich, Berlin, and numerous other cities worldwide.

How to get there

Public transport

After arriving at Cambridge Railway Station, take either the U1 or U2 Universal buses towards "Girton Corner/Eddington" until "William Gates Building". Alternatively, take the X3 towards Huntingdon until "Cam Uni Vet School".

Cycling and Car

Cycling from the Railway Station to the William Gates Building takes about 20 minutes with cycling paths available for the majority of the path. Parking spaces and Bicycle racks are available in front of the building. The building is easily reachable from the M11.