uc-crux-llvm: Serialization of data structures

[langston-barrett]

Introduce functions for (de)serializing the many type-indexed GADTs in UC-Crux. The reasoning behind the overall shape of the implementation is recorded in the module comment on UCCrux.LLVM.View. This will enable features like #982.

This is still a draft because error handling would need to be improved, many of the errors lack sufficient context to really make it easy to see what went wrong during deserialization. However, since this is already fairly large, I wanted to get some initial feedback on the direction before polishing it off.

[langston-barrett]

I'm having trouble reproducing the CI failures. Here's what they look like:

    view-shape:                                                           FAIL
      *** Failed! (after 1 test):
      Exception while generating shrink-list:
        Test.QuickCheck.resize: negative size
        CallStack (from HasCallStack):
          error, called at src/Test/QuickCheck/Gen.hs:135:22 in QuickCheck-2.14.2-0c7f5115b9190e0c296f816bfcd00c19cd356a8b5211cf667467a3d51faa6351:Test.QuickCheck.Gen
      Exception thrown while showing test case:
        Test.QuickCheck.resize: negative size
        CallStack (from HasCallStack):
          error, called at src/Test/QuickCheck/Gen.hs:135:22 in QuickCheck-2.14.2-0c7f5115b9190e0c296f816bfcd00c19cd356a8b5211cf667467a3d51faa6351:Test.QuickCheck.Gen

I can't reproduce this with --quickcheck-replay with GHC 9.0 nor 8.10, though both of these are failing in CI on Ubuntu 20.04 (but not 18.04 nor Windows nor OSX). I also tried cabal update to no avail. The build configuration also looks similar, both CI and I are compiling with -O1. I suppose I'll try writing a Dockerfile for testing this on Ubuntu 20.04.

[langston-barrett]

I was also unable to reproduce the failure using an Ubuntu 20.04 Dockerfile.

Dockerfile

FROM ubuntu:20.04
ENV DEBIAN_FRONTEND=noninteractive
RUN apt-get update -qq && apt-get install -y -qq build-essential curl libffi-dev libffi7 libgmp-dev libgmp10 libncurses-dev libncurses5 libtinfo5 libz-dev
RUN curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh
ENV PATH=$PATH:/root/.ghcup/bin:/root/.cabal/bin
RUN ghcup install ghc 9.2.1 && \
    ghcup install cabal 3.6.2
CMD bash

docker build -t ubuntu . && docker run --mount src=/tmp/cabal,target=/root/.cabal,type=bind --mount src=$PWD,target=/w,type=bind -w /w --rm -it ubuntu bash -c "cd uc-crux-llvm && cabal update && cabal --builddir=build-ubuntu-20.04 run test:uc-crux-llvm-test -- -p /view/"