meson-pgo: initial version of a meson wrapper script for PGO builds

Usage: meson-pgo.sh auto|partial|full <source-dir> <build-dir> <meson-options>

Note: build-dir must *not* exist before the script is run (but if it
does, the script will tell you so, and exit).

Supported compilers: gcc and clang

The script does *not* add _any_ custom meson options, except configure
-Db_pgo. Thus, you probably want to call it like this:

  meson-pgo.sh auto . /tmp/foot-pgo-build --buildtype=release -Db_lto=true

meson-pgo.sh

@@ -0,0 +1,109 @@
+#!/bin/sh
+
+set -e
+
+mode=${1}; shift
+source_dir=$(realpath "${1}"); shift
+build_dir=${1}; shift
+
+if [ -d ${build_dir} ]; then
+    echo "${build_dir}: build directory already exists"
+    exit 1
+fi
+
+case ${mode} in
+    auto|partial|full)
+        ;;
+
+    *)
+        echo "${mode}: invalid PGO mode (must be one of 'auto', 'partial' or 'full')"
+        exit 1
+        ;;
+esac
+
+compiler=other
+do_pgo=no
+
+CFLAGS="${CFLAGS} -O3"
+
+case $(${CC-cc} --version) in
+    *GCC*)
+        compiler=gcc
+        do_pgo=yes
+        ;;
+
+    *clang*)
+        compiler=clang
+
+        if command -v llvm-profdata > /dev/null; then
+            do_pgo=yes
+            CFLAGS="${CFLAGS} -Wno-ignored-optimization-argument"
+        fi
+        ;;
+esac
+
+if [ ${mode} = auto ]; then
+    if [ -n "${WAYLAND_DISPLAY+x}" ]; then
+        mode=full
+    else
+        mode=partial
+    fi
+fi
+
+# echo "source: ${source_dir}"
+# echo "build: ${build_dir}"
+# echo "compiler: ${compiler}"
+# echo "mode: ${mode}"
+
+export CFLAGS
+meson "${@}" "${build_dir}"
+
+if [ ${do_pgo} = yes ]; then
+    find . -name "*.gcda" -delete
+    meson configure "${build_dir}" -Db_pgo=generate
+    ninja -C "${build_dir}"
+
+    # If fcft/tllist are subprojects, we need to ensure their tests
+    # have been executed, or we’ll get “profile count data file not
+    # found” errors.
+    ninja -C "${build_dir}" test
+
+    script_options="--scroll --scroll-region --colors-regular --colors-bright --colors-256 --colors-rgb --attr-bold --attr-italic --attr-underline --sixel"
+
+    tmp_file=$(mktemp)
+    pwd=$(pwd)
+
+    cleanup() {
+        rm -f "${tmp_file}"
+        cd "${pwd}"
+    }
+    trap cleanup EXIT INT HUP TERM
+
+    cd "${build_dir}"
+    if [ ${mode} = full ]; then
+        ./footclient --version
+        ./foot \
+            --config=/dev/null \
+            --term=xterm \
+            sh -c "${source_dir}/scripts/generate-alt-random-writes.py ${script_options} ${tmp_file} && cat ${tmp_file}"
+    else
+        ./footclient --version
+        ./foot --version
+        "${source_dir}/scripts/generate-alt-random-writes.py" \
+            --rows=67 \
+            --cols=135 \
+            ${script_options} \
+            "${tmp_file}"
+        ./pgo "${tmp_file}"
+    fi
+    cd "${pwd}"
+    rm "${tmp_file}"
+
+    if [ ${compiler} = clang ]; then
+        llvm-profdata merge "${build_dir}"/default_*.profraw --output="${build_dir}/default.profdata"
+    fi
+
+    meson configure "${build_dir}" -Db_pgo=use
+else
+    echo "Not doing PGO"
+fi