From dae518d9e0a65f3fd232c29a1d2c165b5f161391 Mon Sep 17 00:00:00 2001
From: Zyad Hassan <zyadh@amazon.com>
Date: Fri, 16 May 2025 19:58:01 -0700
Subject: [PATCH] Add setup scripts for Ubuntu 20.04

---
 docs/src/build-from-source.md                 |  1 +
 scripts/setup/ubuntu-20.04                    |  1 -
 scripts/setup/ubuntu-20.04/install_cbmc.sh    | 32 +++++++++++++++
 scripts/setup/ubuntu-20.04/install_deps.sh    | 40 +++++++++++++++++++
 .../setup/ubuntu-20.04/install_doc_deps.sh    |  8 ++++
 5 files changed, 81 insertions(+), 1 deletion(-)
 delete mode 120000 scripts/setup/ubuntu-20.04
 create mode 100755 scripts/setup/ubuntu-20.04/install_cbmc.sh
 create mode 100755 scripts/setup/ubuntu-20.04/install_deps.sh
 create mode 100755 scripts/setup/ubuntu-20.04/install_doc_deps.sh

diff --git a/docs/src/build-from-source.md b/docs/src/build-from-source.md
index c3d7ecfd4b9a..e7e43b07c6c8 100644
--- a/docs/src/build-from-source.md
+++ b/docs/src/build-from-source.md
@@ -27,6 +27,7 @@ is following our CI scripts:
 git clone https://github.com/model-checking/kani.git
 cd kani
 git submodule update --init
+ # For Ubuntu 20.04, use: `./scripts/setup/ubuntu-20.04/install_deps.sh`
 ./scripts/setup/ubuntu/install_deps.sh
 # If you haven't already (or from https://rustup.rs/):
 ./scripts/setup/install_rustup.sh
diff --git a/scripts/setup/ubuntu-20.04 b/scripts/setup/ubuntu-20.04
deleted file mode 120000
index 7d13753d73e8..000000000000
--- a/scripts/setup/ubuntu-20.04
+++ /dev/null
@@ -1 +0,0 @@
-ubuntu
\ No newline at end of file
diff --git a/scripts/setup/ubuntu-20.04/install_cbmc.sh b/scripts/setup/ubuntu-20.04/install_cbmc.sh
new file mode 100755
index 000000000000..f9744f51f61f
--- /dev/null
+++ b/scripts/setup/ubuntu-20.04/install_cbmc.sh
@@ -0,0 +1,32 @@
+#!/bin/bash
+# Copyright Kani Contributors
+# SPDX-License-Identifier: Apache-2.0 OR MIT
+
+set -eu
+
+# Source kani-dependencies to get CBMC_VERSION
+source kani-dependencies
+
+if [ -z "${CBMC_VERSION:-}" ]; then
+  echo "$0: Error: CBMC_VERSION is not specified"
+  exit 1
+fi
+
+# Binaries are not released for Ubuntu 20.04, so build from source
+WORK_DIR=$(mktemp -d)
+git clone \
+  --branch cbmc-${CBMC_VERSION} --depth 1 \
+  https://github.com/diffblue/cbmc \
+  "${WORK_DIR}"
+
+pushd "${WORK_DIR}"
+
+cmake -S . -Bbuild -DWITH_JBMC=OFF -Dsat_impl="minisat2;cadical" \
+  -DCMAKE_C_COMPILER=gcc-10 -DCMAKE_CXX_COMPILER=g++-10 \
+  -DCMAKE_CXX_STANDARD_LIBRARIES=-lstdc++fs \
+  -DCMAKE_CXX_FLAGS=-Wno-error=register
+cmake --build build -- -j$(nproc)
+sudo make -C build install
+
+popd
+rm -rf "${WORK_DIR}"
diff --git a/scripts/setup/ubuntu-20.04/install_deps.sh b/scripts/setup/ubuntu-20.04/install_deps.sh
new file mode 100755
index 000000000000..d9e272d18a84
--- /dev/null
+++ b/scripts/setup/ubuntu-20.04/install_deps.sh
@@ -0,0 +1,40 @@
+#!/bin/bash
+# Copyright Kani Contributors
+# SPDX-License-Identifier: Apache-2.0 OR MIT
+
+set -eu
+
+# Dependencies.
+DEPS=(
+  bison
+  cmake
+  curl
+  flex
+  # CBMC needs g++-10 which doesn't come by default on Ubuntu 20.04
+  g++-10
+  gcc
+  git
+  gpg-agent
+  make
+  patch
+  wget
+  zlib1g
+  zlib1g-dev
+)
+
+set -x
+
+# Github promises weekly build image updates, but recommends running
+# `sudo apt-get update` before installing packages in case the `apt`
+# index is stale. This prevents package installation failures.
+# https://docs.github.com/en/actions/using-github-hosted-runners/customizing-github-hosted-runners#installing-software-on-ubuntu-runners
+sudo apt-get --yes update
+
+sudo DEBIAN_FRONTEND=noninteractive apt-get install --no-install-recommends --yes "${DEPS[@]}"
+
+# Get the directory containing this script
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+
+${SCRIPT_DIR}/install_cbmc.sh
+# The Kissat installation script is platform-independent, so is placed one level up
+${SCRIPT_DIR}/../install_kissat.sh
diff --git a/scripts/setup/ubuntu-20.04/install_doc_deps.sh b/scripts/setup/ubuntu-20.04/install_doc_deps.sh
new file mode 100755
index 000000000000..e3f4dd2c0d74
--- /dev/null
+++ b/scripts/setup/ubuntu-20.04/install_doc_deps.sh
@@ -0,0 +1,8 @@
+#!/bin/bash
+# Copyright Kani Contributors
+# SPDX-License-Identifier: Apache-2.0 OR MIT
+
+set -eux
+
+cargo install mdbook-graphviz
+DEBIAN_FRONTEND=noninteractive sudo apt-get install --no-install-recommends --yes graphviz