Meta: Add script to analyze coverage data from an existing disk image

The analyze-qemu-coverage.sh script cracks open the _disk_image for the
given SERENITY_ARCH and SERENITY_TOOLCHAIN and extracts llvm profile
data into a local directory owned by the current user. It then calls a
coverage artifact script from llvm to create a nice html report for all
the source files referenced by the profile data files.

We currently grab a script from llvm via wget. In the future a custom
script to call llvm-cov and llvm-profdata should probably be used.

Meta/analyze-qemu-coverage.sh

@@ -0,0 +1,74 @@
+#!/usr/bin/env bash
+
+set -eo pipefail
+
+SCRIPT_DIR="$(dirname "${0}")"
+
+if [ -z "$SERENITY_ARCH" ]; then
+    SERENITY_ARCH="i686"
+fi
+
+toolchain_suffix=
+if [ "$SERENITY_TOOLCHAIN" = "Clang" ]; then
+    toolchain_suffix="clang"
+fi
+
+BUILD_DIR="${SCRIPT_DIR}/../Build/${SERENITY_ARCH}${toolchain_suffix}"
+TEMP_PROFDATA="$BUILD_DIR/tmp_profile_data"
+
+mkdir -p "$TEMP_PROFDATA"
+mkdir -p "$BUILD_DIR/mnt"
+
+[ -z "${ELEVATE+x}" ] && ELEVATE="sudo"
+echo "ELEVATE is $ELEVATE"
+
+echo "[ELEVATED] Mounting _disk_image into $BUILD_DIR/mnt, this requires elevated privileges..."
+"$ELEVATE" mount "$BUILD_DIR/_disk_image" "$BUILD_DIR/mnt"
+echo "[ELEVATED] Copying profile data files out of $BUILD_DIR/mnt, this requires elevated privileges..."
+"$ELEVATE" cp -r "$BUILD_DIR/mnt/home/anon/profiles" "$TEMP_PROFDATA/"
+echo "[ELEVATED] Unmounting _disk_image, this requires elevated privileges..."
+"$ELEVATE" umount "$BUILD_DIR/mnt"
+echo "[ELEVATED] Making sure profile data files are owned by the current user, this requires elevated privileges..."
+"$ELEVATE" chown -R "$(id -u)":"$(id -g)" "$TEMP_PROFDATA/"
+
+
+echo "Moving profile data into $TEMP_PROFDATA directly..."
+mv "$TEMP_PROFDATA"/profiles/* "$TEMP_PROFDATA/"
+
+echo "Discovering all binaries and shared libraries in $BUILD_DIR/Root"
+# shellcheck disable=SC2156 # The recommended fix on the Shellcheck github page for this warning causes the script to not find any files at all
+mapfile -d '\n' all_binaries < <(find "$BUILD_DIR"/Root -type f -exec sh -c "file {} | grep -vi relocatable | grep -Eiq ': elf (32|64)-bit'" \; -print | grep -Ev '(usr\/Tests|usr\/local|boot\/|Loader.so)')
+
+# FIXME: Come up with our own coverage prep script instead of using llvm's
+COVERAGE_PREPARE="$BUILD_DIR/prepare-code-coverage-artifact.py"
+if [ ! -f "$COVERAGE_PREPARE" ]; then
+    # Download coverage prep script from github
+    LLVM_14_RELEASE_HASH=329fda39c507e8740978d10458451dcdb21563be
+    SHA256_SUM=2cf1019d1df9a10c87234e0ec9c984dbb97d5543688b7f4a7387cb377ced7f21
+    URL=https://raw.githubusercontent.com/llvm/llvm-project/${LLVM_14_RELEASE_HASH}/llvm/utils/prepare-code-coverage-artifact.py
+
+    echo "Downloading prepare-code-coverage-artifact.py from ${URL}"
+    wget "$URL" -P "$BUILD_DIR"
+
+    # Verify hash matches for integrity
+    echo "Expecting sha256sum: $SHA256_SUM"
+    CALC_SUM="$(sha256sum "${COVERAGE_PREPARE}" | cut -f1 -d' ')"
+    echo "sha256sum($COVERAGE_PREPARE) = '$CALC_SUM'"
+    if [ "$CALC_SUM" != "$SHA256_SUM" ]; then
+        # remove downloaded file to re-download on next run
+        rm -f "$COVERAGE_PREPARE"
+        echo "sha256sums mismatching, removed erroneous download. Please re-try."
+        exit 1
+    fi
+fi
+
+CLANG_BINDIR="${SCRIPT_DIR}/../Toolchain/Local/clang/bin"
+
+# shellcheck disable=SC2128,SC2086 # all_binaries variable needs expanded to space separated string, not newline separated string
+python3 "$COVERAGE_PREPARE" \
+    --unified-report \
+    -C "$SCRIPT_DIR/.." \
+    "$CLANG_BINDIR/llvm-profdata" "$CLANG_BINDIR/llvm-cov" \
+    "$TEMP_PROFDATA/" \
+    "$BUILD_DIR/reports/" \
+    $all_binaries