Generic Makefile for simple C projects, supporting compilation databases via Clang.

Makefile

# Variables (all configuration should happen here)

SHELL = /bin/sh

CC = clang
CFLAGS = -Wall -Wextra -Wpedantic -std=c99

LDFLAGS =

RELEASE_CFLAGS = -Os
DEBUG_CFLAGS = -g -O0 -DDEBUG

RELEASE_LDFLAGS =
DEBUG_LDFLAGS =

SOURCE_DIR = src
BUILD_DIR = build

SOURCES = $(wildcard $(SOURCE_DIR)/*.c)
OBJECTS = $(patsubst $(SOURCE_DIR)/%.c, $(BUILD_DIR)/%.o, $(SOURCES))
EXECUTABLE = $(BUILD_DIR)/hello_world

COMPILATION_DATABASE_ENTRIES = $(addsuffix .json,$(OBJECTS))
COMPILATION_DATABASE = compile_commands.json

# PHONY targets, i.e. not linked to a file

.PHONY: all run release debug compilation_db

all: release

run: ./$(EXECUTABLE)

release: CFLAGS += $(RELEASE_CFLAGS)
release: LDFLAGS += $(RELEASE_LDFLAGS)
release: $(EXECUTABLE)

debug: CFLAGS += $(DEBUG_CFLAGS)
debug: LDFLAGS += $(DEBUG_LDFLAGS)
debug: $(EXECUTABLE)

compilation_db: DEBUG_CFLAGS += -MJ [email protected]
compilation_db: clean $(OBJECTS) $(COMPILATION_DATABASE)

# File targets

$(BUILD_DIR):
	@mkdir $(BUILD_DIR)

$(EXECUTABLE): $(OBJECTS)
	$(info Linking executable "$@")
	@$(CC) $(CFLAGS) $(LDFLAGS) $^ -o $@

$(BUILD_DIR)/%.o: $(SOURCE_DIR)/%.c | $(BUILD_DIR)
	$(info Compiling object file "$@")
	@$(CC) $(CFLAGS) -c $< -o $@

$(COMPILATION_DATABASE):
	$(info (Re)generating compilation database)
	@sed -e '1s/^/[/' -e '$$s/,$$/]/' \
     $(COMPILATION_DATABASE_ENTRIES) > $@

# Cleaning targets

.PHONY: clean mrproper

clean:
	$(info Deleting object files)
	@$(RM) $(OBJECTS)
	@$(RM) $(COMPILATION_DATABASE_ENTRIES)

mrproper: clean
	$(info Deleting build directory)
	@$(RM) -r $(BUILD_DIR)
	$(info Deleting compilation database)
	@$(RM) $(COMPILATION_DATABASE)