Makefile

# MIT License
#
# Copyright (c) 2020 Misha Krieger-Raynauld
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
###############################################################################

###############################################################################
#### Variables and settings
###############################################################################

# Executable name
EXEC = Expresso

# Build, bin, assets, and install directories (bin and build root directories are kept for clean)
BUILD_DIR_ROOT = build
BIN_DIR_ROOT = bin
ASSETS_DIR = assets
ASSETS_OS_DIR := $(ASSETS_DIR)_os
INSTALL_DIR := ~/Desktop/$(EXEC)

# Sources (searches recursively inside the source directory)
SRC_DIR = src
SRCS := $(sort $(shell find $(SRC_DIR) -name '*.c'))

# Includes
INCLUDE_DIR = include
INCLUDES := -I$(INCLUDE_DIR)
INCLUDES += $(shell find $(INCLUDE_DIR) -type d | sed 's/^/-I/g')

# C preprocessor settings
CPPFLAGS = $(INCLUDES) -MMD -MP -fopenmp

# C compiler settings
CC = gcc
CFLAGS = -std=c11
WARNINGS = -Wall -Wpedantic -Wextra

# Linker flags
LDFLAGS = -fopenmp -Lexternal

# Libraries to link
LDLIBS = -lSDL2 -lm

# Target OS detection
ifeq ($(OS),Windows_NT) # OS is a preexisting environment variable on Windows
	OS = windows
else
	UNAME := $(shell uname -s)
	ifeq ($(UNAME),Darwin)
		OS = macos
	else ifeq ($(UNAME),Linux)
		OS = linux
	else
    	$(error OS not supported by this Makefile)
	endif
endif

# OS-specific settings
ifeq ($(OS),windows)
	# Link libgcc and libstdc++ statically on Windows
	LDFLAGS += -static-libgcc -static-libstdc++

	# Windows 32- and 64-bit common settings
	INCLUDES +=
	LDFLAGS +=
	LDLIBS +=

	ifeq ($(win32),1)
		# Windows 32-bit settings
		INCLUDES +=
		LDFLAGS +=
		LDLIBS +=
	else
		# Windows 64-bit settings
		INCLUDES +=
		LDFLAGS +=
		LDLIBS +=
	endif
else ifeq ($(OS),macos)
	# macOS-specific settings
	INCLUDES +=
	LDFLAGS +=
	LDLIBS +=
else ifeq ($(OS),linux)
	# Linux-specific settings
	INCLUDES +=
	LDFLAGS +=
	LDLIBS +=
endif

################################################################################
#### Final setup
################################################################################

# Windows-specific default settings
ifeq ($(OS),windows)
	# Add .exe extension to executable
	EXEC := $(EXEC).exe

	ifeq ($(win32),1)
		# Compile for 32-bit
		CFLAGS += -m32
	else
		# Compile for 64-bit
		CFLAGS += -m64
	endif
endif

# OS-specific build, bin, and assets directories
BUILD_DIR := $(BUILD_DIR_ROOT)/$(OS)
BIN_DIR := $(BIN_DIR_ROOT)/$(OS)
ASSETS_OS_DIR := $(ASSETS_OS_DIR)/$(OS)
ifeq ($(OS),windows)
	# Windows 32-bit
	ifeq ($(win32),1)
		BUILD_DIR := $(BUILD_DIR)32
		BIN_DIR := $(BIN_DIR)32
		ASSETS_OS_DIR := $(ASSETS_OS_DIR)32
	# Windows 64-bit
	else
		BUILD_DIR := $(BUILD_DIR)64
		BIN_DIR := $(BIN_DIR)64
		ASSETS_OS_DIR := $(ASSETS_OS_DIR)64
	endif
endif

# Debug (default) and release modes settings
ifeq ($(release),1)
	BUILD_DIR := $(BUILD_DIR)/release
	BIN_DIR := $(BIN_DIR)/release
	CFLAGS += -O3
	CPPFLAGS += -DNDEBUG
else
	BUILD_DIR := $(BUILD_DIR)/debug
	BIN_DIR := $(BIN_DIR)/debug
	CFLAGS += -O0 -g
endif

# Objects and dependencies
OBJS := $(SRCS:$(SRC_DIR)/%.c=$(BUILD_DIR)/%.o)
DEPS := $(OBJS:.o=.c.d)
COMPDBS := $(OBJS:.o=.json)

# All files (sources and headers)
FILES := $(shell find $(SRC_DIR) $(INCLUDE_DIR) -name '*.c' -o -name '*.h' -o -name '*.inl')

################################################################################
#### Targets
################################################################################

.PHONY: all
all: $(BIN_DIR)/$(EXEC)

# Build executable
$(BIN_DIR)/$(EXEC): $(OBJS)
	@echo "Building executable: $@"
	@mkdir -p $(@D)
	@$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@

# Compile C source files
$(BUILD_DIR)/%.o: $(SRC_DIR)/%.c
	@echo "Compiling: $<"
	@mkdir -p $(@D)
	@$(CC) $(CPPFLAGS) $(CFLAGS) $(WARNINGS) -c $< -o $@

# Include automatically generated dependencies
-include $(DEPS)

# Install packaged program
.PHONY: install
install: all copyassets
	@echo "Packaging program to $(INSTALL_DIR)"
	@mkdir -p $(INSTALL_DIR) && cp -r $(BIN_DIR)/. $(INSTALL_DIR)

# Build and run
.PHONY: run
run: all
	@echo "Starting program: $(BIN_DIR)/$(EXEC)"
	@cd $(BIN_DIR) && ./$(EXEC)

# Copy assets to bin directory for selected platform
.PHONY: copyassets
copyassets:
	@echo "Copying assets from $(ASSETS_DIR) and $(ASSETS_OS_DIR) to $(BIN_DIR)"
	@mkdir -p $(BIN_DIR)
	@cp -r $(ASSETS_DIR)/. $(BIN_DIR)/
	@cp -r $(ASSETS_OS_DIR)/. $(BIN_DIR)/ 2> /dev/null || :

# Clean all assets from bin directories for all platforms
.PHONY: cleanassets
cleanassets:
	@echo "Cleaning assets for all platforms"
	@find $(BIN_DIR_ROOT) -mindepth 3 ! -name $(EXEC) -delete

# Clean build and bin directories for all platforms
.PHONY: clean
clean:
	@echo "Cleaning $(BUILD_DIR_ROOT) and $(BIN_DIR_ROOT) directories"
	@$(RM) -r $(BUILD_DIR_ROOT)
	@$(RM) -r $(BIN_DIR_ROOT)

.PHONY: compdb
compdb: $(BUILD_DIR_ROOT)/compile_commands.json

# Generate JSON compilation database (compile_commands.json) by merging fragments
$(BUILD_DIR_ROOT)/compile_commands.json: $(COMPDBS)
	@echo "Generating: $@"
	@mkdir -p $(@D)
	@printf "[\n" > $@
	@sed -e '$$s/$$/,/' -s $(COMPDBS) | sed -e '$$s/,$$//' -e 's/^/    /' >> $@
	@printf "]\n" >> $@

# Generate JSON compilation database fragments from source files
$(BUILD_DIR)/%.json: $(SRC_DIR)/%.c
	@mkdir -p $(@D)
	@printf "\
	{\n\
	    \"directory\": \"$(CURDIR)\",\n\
	    \"command\": \"$(CC) $(CPPFLAGS) $(CFLAGS) $(WARNINGS) -c $< -o $(basename $@).o\",\n\
	    \"file\": \"$<\"\n\
	}\n" > $@

# Run clang-format on source code
.PHONY: format
format:
	@echo "Running clang-format"
	@clang-format -i $(FILES)

# Dry-run clang-format on source code to check for formatting errors
.PHONY: format-check
format-check:
	@echo "Checking clang-format"
	@clang-format --dry-run --Werror $(FILES)

# Run clang-tidy on source code
.PHONY: lint
lint: compdb
	@echo "Running clang-tidy"
	@clang-tidy -p $(BUILD_DIR_ROOT) --warnings-as-errors='*' $(FILES)

# Run clang-tidy on source code and fix found errors
.PHONY: lint-fix
lint-fix: compdb
	@echo "Running clang-tidy --fix"
	@clang-tidy -p $(BUILD_DIR_ROOT) --fix $(FILES)

# Generate documentation with Doxygen
.PHONY: docs
docs:
	@echo "Generating documentation"
	@doxygen docs/Doxyfile

# Print help information
.PHONY: help
help:
	@printf "\
	Usage: make target... [options]...\n\
	\n\
	Targets:\n\
	  all             Build executable (debug mode by default) (default target)\n\
	  install         Install packaged program to desktop (debug mode by default)\n\
	  run             Build and run executable (debug mode by default)\n\
	  copyassets      Copy assets to executable directory for selected platform and configuration\n\
	  cleanassets     Clean assets from executable directories (all platforms)\n\
	  clean           Clean build and bin directories (all platforms)\n\
	  compdb          Generate JSON compilation database (compile_commands.json)\n\
	  format          Format source code using clang-format\n\
	  format-check    Check that source code is formatted using clang-format\n\
	  lint            Lint source code using clang-tidy\n\
	  lint-fix        Lint and fix source code using clang-tidy\n\
	  docs            Generate documentation with Doxygen\n\
	  help            Print this information\n\
	  printvars       Print Makefile variables for debugging\n\
	\n\
	Options:\n\
	  release=1       Run target using release configuration rather than debug\n\
	  win32=1         Build for 32-bit Windows (valid when built on Windows only)\n\
	\n\
	Note: the above options affect the all, install, run, copyassets, compdb, and printvars targets\n"

# Print Makefile variables
.PHONY: printvars
printvars:
	@printf "\
	OS: \"$(OS)\"\n\
	EXEC: \"$(EXEC)\"\n\
	BUILD_DIR: \"$(BUILD_DIR)\"\n\
	BIN_DIR: \"$(BIN_DIR)\"\n\
	ASSETS_DIR: \"$(ASSETS_DIR)\"\n\
	ASSETS_OS_DIR: \"$(ASSETS_OS_DIR)\"\n\
	INSTALL_DIR: \"$(INSTALL_DIR)\"\n\
	SRC_DIR: \"$(SRC_DIR)\"\n\
	SRCS: \"$(SRCS)\"\n\
	INCLUDE_DIR: \"$(INCLUDE_DIR)\"\n\
	INCLUDES: \"$(INCLUDES)\"\n\
	CC: \"$(CC)\"\n\
	CPPFLAGS: \"$(CPPFLAGS)\"\n\
	CFLAGS: \"$(CFLAGS)\"\n\
	WARNINGS: \"$(WARNINGS)\"\n\
	LDFLAGS: \"$(LDFLAGS)\"\n\
	LDLIBS: \"$(LDLIBS)\"\n"