CMake: Add options for profile guided optimization

A PGO'd binary can be built as follows:

1. Build with `-DDEVILUTIONX_PROFILE_GENERATE=ON`.
3. Run the timedemo.
4. Build with `-DDEVILUTIONX_PROFILE_USE=ON`.
By default, the profile directory is at `${HOME}/devilutionx-profile`

Example for the RG99:

```bash
# Build the OPK for profiling data collection:
TOOLCHAIN=/opt/rs90-toolchain Packaging/OpenDingux/build.sh rg99 --profile-generate

# Copy the OPK to RG99:
scp -O build-rg99/devilutionx-rg99.opk rg99:/media/sdcard/apps

# Now, run the OPK. It will run the timedemo instead of the actual game and will take a couple of hours.
# ☕☕☕

# Copy the profiling data from RG99
scp -r -O rg99:/media/data/local/home/devilutionx-profile /tmp/devilutionx-profile

# Build the OPK use the collected profiling data:
TOOLCHAIN=/opt/rs90-toolchain Packaging/OpenDingux/build.sh rg99 --profile-use --profile-dir /tmp/devilutionx-profile

# Copy the resulting binary back to RG99
scp -O build-rg99/devilutionx-rg99.opk rg99:/media/sdcard/apps
```

CMake/platforms/rg99.cmake

@@ -2,7 +2,6 @@
 set(BUILD_ASSETS_MPQ OFF)
 set(UNPACKED_MPQS ON)
 set(NONET ON)
-set(DISABLE_DEMOMODE ON)
 set(USE_SDL1 ON)
 
 # Link `libstdc++` dynamically: ~1.3 MiB.

CMakeLists.txt

@@ -117,6 +117,9 @@ option(PIE "Generate position-independent code" OFF)
 cmake_dependent_option(DEVILUTIONX_DISABLE_RTTI "Disable RTTI" ON "NONET" OFF)
 cmake_dependent_option(DEVILUTIONX_DISABLE_EXCEPTIONS "Disable exceptions" ON "NONET" OFF)
 RELEASE_OPTION(DEVILUTIONX_STATIC_CXX_STDLIB "Link C++ standard library statically (if available)")
+option(DEVILUTIONX_PROFILE_GENERATE "Build a binary that generates the profile for PGO" OFF)
+option(DEVILUTIONX_PROFILE_USE "Build with PGO using the given profile file" OFF)
+set(DEVILUTIONX_PROFILE_DIR "" CACHE STRING "Directory where the profile is stored")
 
 include(MoldLinker)
 
@@ -225,6 +228,15 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang" AND NOT PS4)
   endif()
 endif()
 
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
+  add_compile_options("$<$<BOOL:${DEVILUTIONX_PROFILE_GENERATE}>:-fprofile-generate>")
+  add_link_options("$<$<BOOL:${DEVILUTIONX_PROFILE_GENERATE}>:-fprofile-generate>")
+  add_compile_options("$<$<BOOL:${DEVILUTIONX_PROFILE_USE}>:-fprofile-use>")
+  add_link_options("$<$<BOOL:${DEVILUTIONX_PROFILE_USE}>:-fprofile-use>")
+  add_compile_options("$<$<BOOL:${DEVILUTIONX_PROFILE_DIR}>:-fprofile-dir=${DEVILUTIONX_PROFILE_DIR}>")
+  add_link_options("$<$<BOOL:${DEVILUTIONX_PROFILE_DIR}>:-fprofile-dir=${DEVILUTIONX_PROFILE_DIR}>")
+endif()
+
 # Not a genexp because CMake doesn't support it
 # https://gitlab.kitware.com/cmake/cmake/-/issues/20546
 if(NOT DISABLE_LTO)

Packaging/OpenDingux/build.sh

@@ -8,17 +8,10 @@ source Packaging/OpenDingux/targets.sh
 source Packaging/OpenDingux/package-opk.sh
 
 usage() {
-  echo "Usage: build.sh [target]"
-  usage_target
+  >&2 echo "Usage: build.sh [--profile-generate|--profile-use] [--profile-dir PATH] [target]"
+  >&2 usage_target
 }
 
-if ! check_target "$@"; then
-  usage
-  exit 64
-fi
-
-declare -r TARGET="$1"
-declare -r BUILD_DIR="build-${TARGET}"
 declare -rA BUILDROOT_REPOS=(
 	[lepus]=https://github.com/OpenDingux/buildroot.git
 	[retrofw]=https://github.com/retrofw/buildroot.git
@@ -34,15 +27,29 @@ declare -rA BUILDROOT_DEFCONFIGS=(
 	[gkd350h]='rg350_defconfig BR2_EXTERNAL=board/opendingux'
 )
 
-declare BUILDROOT_TARGET="$TARGET"
+declare TARGET
+declare BUILD_DIR
+declare BUILDROOT
+declare BUILDROOT_TARGET
+declare TOOLCHAIN
 
-# If a TOOLCHAIN environment variable is set, just use that.
-if [[ -z ${TOOLCHAIN:-} ]]; then
-	BUILDROOT="${BUILDROOT:-$HOME/devilutionx-buildroots/$BUILDROOT_TARGET}"
-	TOOLCHAIN="${BUILDROOT}/output/host"
-fi
+declare -a CMAKE_CONFIGURE_OPTS=()
+declare PROFILE_GENERATE=0
+declare PROFILE_USE=0
+declare PROFILE_DIR="%q{HOME}/devilutionx-profile"
+declare BUILD_TYPE=release
 
 main() {
+	parse_args "$@"
+	BUILD_DIR="build-${TARGET}"
+	BUILDROOT_TARGET="$TARGET"
+
+	# If a TOOLCHAIN environment variable is set, just use that.
+	if [[ -z ${TOOLCHAIN:-} ]]; then
+		BUILDROOT="${BUILDROOT:-$HOME/devilutionx-buildroots/$BUILDROOT_TARGET}"
+		TOOLCHAIN="${BUILDROOT}/output/host"
+	fi
+
 	>&2 echo "Building for target ${TARGET} in ${BUILD_DIR}"
 	set -x
 	if [[ -n ${BUILDROOT:-} ]]; then
@@ -53,6 +60,74 @@ main() {
 	package_opk
 }
 
+parse_args() {
+	local -a positional=()
+	while [[ $# -gt 0 ]]; do
+		case "$1" in
+		--profile-generate)
+			PROFILE_GENERATE=1
+			shift
+			;;
+		--profile-use)
+			PROFILE_USE=1
+			shift
+			;;
+		--profile-dir)
+			shift
+			if [[ $# -eq 0 ]]; then
+				usage
+				exit 64
+			fi
+			PROFILE_DIR="$1"
+			shift
+			;;
+		-*|--*)
+			>&2 echo "Error: unknown argument $1"
+			>&2 echo
+			usage
+			exit 64
+			;;
+		*)
+			positional+=("$1")
+			shift
+			;;
+		esac
+	done
+	if [[ ${#positional[@]} -ne 1 ]] || ! check_target "${positional[0]}"; then
+		>&2 echo "Error: target is required"
+		>&2 echo
+		usage
+		exit 64
+	fi
+	TARGET="${positional[0]}"
+
+	if (( PROFILE_GENERATE )) && (( PROFILE_USE )); then
+		>&2 echo "Error: at most one of --profile-use and --profile-generate is allowed"
+		exit 64
+	fi
+	if (( PROFILE_GENERATE )); then
+		CMAKE_CONFIGURE_OPTS+=(
+			"-DDEVILUTIONX_PROFILE_GENERATE=ON"
+			"-DDEVILUTIONX_PROFILE_DIR=${PROFILE_DIR}"
+		)
+		BUILD_TYPE=relwithdebinfo
+		OPK_DESKTOP_NAME="DevilutionX PG"
+		OPK_DESKTOP_EXEC="profile-generate.sh"
+		OPK_EXTRA_FILES=(
+			Packaging/OpenDingux/profile-generate.sh
+			test/fixtures/timedemo/WarriorLevel1to2/demo_0.dmo
+			test/fixtures/timedemo/WarriorLevel1to2/demo_0_reference_spawn_0.sv
+			test/fixtures/timedemo/WarriorLevel1to2/spawn_0.sv
+		)
+	fi
+	if (( PROFILE_USE )); then
+		CMAKE_CONFIGURE_OPTS+=(
+			"-DDEVILUTIONX_PROFILE_USE=ON"
+			"-DDEVILUTIONX_PROFILE_DIR=${PROFILE_DIR}"
+		)
+	fi
+}
+
 prepare_buildroot() {
 	if [[ -d $BUILDROOT ]]; then
 		return
@@ -90,7 +165,7 @@ cmake_configure() {
 		-DDEVILUTIONX_SYSTEM_LIBSODIUM=OFF \
 		-DDEVILUTIONX_SYSTEM_BZIP2=OFF \
 		-DSTACK_PROTECTOR=OFF \
-		"$@"
+		"${CMAKE_CONFIGURE_OPTS[@]}"
 }
 
 cmake_build() {
@@ -102,30 +177,30 @@ strip_bin() {
 }
 
 build_debug() {
-	cmake_configure -DCMAKE_BUILD_TYPE=Debug -DASAN=OFF -DUBSAN=OFF -DCMAKE_CXX_FLAGS_DEBUG="-g -fno-omit-frame-pointer"
+	cmake_configure -DCMAKE_BUILD_TYPE=Debug -DASAN=OFF -DUBSAN=OFF -DCMAKE_CXX_FLAGS_DEBUG="-g -fno-omit-frame-pointer" "$@"
 	cmake_build
 }
 
 build_relwithdebinfo() {
-	cmake_configure -DCMAKE_BUILD_TYPE=RelWithDebInfo
+	cmake_configure -DCMAKE_BUILD_TYPE=RelWithDebInfo "$@"
 	cmake_build
 }
 
 build_minsizerel() {
-	cmake_configure -DCMAKE_BUILD_TYPE=MinSizeRel
+	cmake_configure -DCMAKE_BUILD_TYPE=MinSizeRel "$@"
 	cmake_build
 	strip_bin
 }
 
 build_release() {
-	cmake_configure -DCMAKE_BUILD_TYPE=Release
+	cmake_configure -DCMAKE_BUILD_TYPE=Release "$@"
 	cmake_build
 	strip_bin
 }
 
 build() {
 	rm -f "${BUILD_DIR}/CMakeCache.txt"
-	build_release
+	build_"$BUILD_TYPE" "$@"
 }
 
-main
+main "$@"

Packaging/OpenDingux/package-opk.sh

@@ -1,5 +1,9 @@
 #!/usr/bin/env bash
 
+declare OPK_DESKTOP_NAME
+declare OPK_DESKTOP_EXEC
+declare -a OPK_EXTRA_FILES
+
 package_opk() {
 	local ext
 	if [[ $TARGET == rg350 ]] || [[ $TARGET == gkd350h ]]; then
@@ -13,10 +17,19 @@ package_opk() {
 	mkdir -p "$tmp"
 	cp "Packaging/OpenDingux/${TARGET}.desktop" "${tmp}/default.${ext}.desktop"
 	cp "Packaging/OpenDingux/${TARGET}-manual.txt" "${tmp}/readme.${ext}.txt"
+
+	if [[ -v OPK_DESKTOP_NAME ]]; then
+		sed -i "s/Name=.*/Name=${OPK_DESKTOP_NAME}/" "${tmp}/default.${ext}.desktop"
+	fi
+	if [[ -v OPK_DESKTOP_EXEC ]]; then
+		sed -i "s/Exec=.*/Exec=${OPK_DESKTOP_EXEC}/" "${tmp}/default.${ext}.desktop"
+	fi
+
 	mksquashfs "${BUILD_DIR}/devilutionx" \
 		"${tmp}/default.${ext}.desktop" \
 		"${tmp}/readme.${ext}.txt" Packaging/resources/icon_32.png \
 		"${BUILD_DIR}/assets/" \
+		"${OPK_EXTRA_FILES[@]}" \
 		"${BUILD_DIR}/devilutionx-${TARGET}.opk" \
 		-all-root -no-xattrs -noappend -no-exports -no-progress
 }

Packaging/OpenDingux/profile-generate.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+
+set -x
+
+SAVE_DIR="$(mktemp -d)"
+ln -s "${PWD}/demo_0_reference_spawn_0.sv" "${SAVE_DIR}/"
+ln -s "${PWD}/demo_0.dmo" "${SAVE_DIR}/"
+cp "${PWD}/spawn_0.sv" "${SAVE_DIR}/"
+./devilutionx --diablo --spawn --demo 0 --timedemo --save-dir "$SAVE_DIR" --data-dir ~/.local/share/diasurgical/devilution
+rm -rf "$SAVE_DIR"