Add a script to build programs with mold using Docker

.gitignore

@@ -8,3 +8,4 @@ core
 ld
 oneTBB
 mimalloc
+gentoo

gentoo-test.sh

@@ -0,0 +1,60 @@
+#!/bin/bash
+#
+# This test script builds lots of programs using mold in a Docker
+# environment to make sure that mold can build programs in the wild.
+# We are using Gentoo Linux as a build environment, because its
+# source-based package allows us to build programs without any hassle.
+
+if [ "$1" = "" ]; then
+  echo "Usage: $0 gentoo-package-name"
+  exit 1
+fi
+
+set -x
+
+# Create a Docker image
+if ! docker image ls mold-gentoo | grep -q mold-gentoo; then
+  set -e
+  cat <<EOF | docker build -t mold-gentoo -
+FROM gentoo/stage3
+RUN echo 'FEATURES="${FEATURE} noclean nostrip -ipc-sandbox -network-sandbox -pid-sandbox -sandbox"' >> /etc/portage/make.conf
+RUN emerge-webrsync
+EOF
+  set +e
+fi
+
+# Build mold as a statically-linked executable
+if ! [ -f mold ] || ! ldd mold 2>&1 | grep -q 'not a dynamic executable'; then
+  make clean
+  ./build-static.sh
+fi
+
+# Build a given package in Docker
+run() {
+  package="$1"
+  cmd="FEATURES=test MAKEOPTS=-j8 emerge $package"
+  filename=`echo "$package" | sed 's!/!_!g'`
+  link="ln -sf /mold/mold /usr/x86_64-pc-linux-gnu/bin/ld"
+
+  mkdir -p gentoo/success gentoo/failure
+  docker run --rm --cap-add=SYS_PTRACE -v `pwd`:/mold mold-gentoo \
+    bash -c "$cmd" > gentoo/$filename.ld
+
+  if [ $? = 0 ]; then
+    mv gentoo/$filename.ld gentoo/success
+  else
+    mv gentoo/$filename.ld gentoo/failure
+  fi
+
+  docker run --rm --cap-add=SYS_PTRACE -v `pwd`:/mold mold-gentoo \
+    bash -c "$link; $cmd" > gentoo/$filename.mold
+
+  if [ $? = 0 ]; then
+    mv gentoo/$filename.mold gentoo/success
+  else
+    mv gentoo/$filename.mold gentoo/failure
+  fi
+}
+
+# Run a test
+run "$1"