Project: Makefile đa cấu hình

project/
  src/            ma nguon .c
  include/        header .h cong khai
  build/          file sinh ra (.o, .d, binary), them vao .gitignore
  tests/          ma kiem thu
  Makefile
  README.md

# ===== Cau hinh =====
CC       := gcc
CSTD     := -std=c17
WARN     := -Wall -Wextra -Wpedantic -Wshadow -Wstrict-prototypes
INCLUDES := -Iinclude
CFLAGS   := $(CSTD) $(WARN) $(INCLUDES) -MMD -MP
LDFLAGS  :=
LDLIBS   := -lm

SRC_DIR   := src
BUILD_DIR := build
TARGET    := $(BUILD_DIR)/app

SRCS := $(wildcard $(SRC_DIR)/*.c)
OBJS := $(SRCS:$(SRC_DIR)/%.c=$(BUILD_DIR)/%.o)
DEPS := $(OBJS:.o=.d)

# ===== Muc tieu mac dinh =====
.PHONY: all
all: debug

# ===== Ba cau hinh build =====
.PHONY: debug release asan
debug:   CFLAGS  += -g3 -O0 -DDEBUG
debug:   $(TARGET)

release: CFLAGS  += -O2 -DNDEBUG -flto -D_FORTIFY_SOURCE=2 -fstack-protector-strong
release: LDFLAGS += -flto
release: $(TARGET)

asan:    CFLAGS  += -g -O1 -fsanitize=address,undefined -fno-omit-frame-pointer
asan:    LDFLAGS += -fsanitize=address,undefined
asan:    $(TARGET)

# ===== Quy tac build =====
$(TARGET): $(OBJS)
	@mkdir -p $(dir $@)
	$(CC) $(OBJS) $(LDFLAGS) $(LDLIBS) -o $@
	@echo "==> Da build: $@"

$(BUILD_DIR)/%.o: $(SRC_DIR)/%.c
	@mkdir -p $(dir $@)
	$(CC) $(CFLAGS) -c $< -o $@

# ===== Phu thuoc header tu dong =====
-include $(DEPS)

# ===== Tien ich =====
.PHONY: clean run test help
clean:
	rm -rf $(BUILD_DIR)

run: $(TARGET)
	./$(TARGET)

test: $(TARGET)
	@$(MAKE) -C tests

help:
	@echo "make debug    - build ban debug (mac dinh)"
	@echo "make release  - build ban toi uu, gia co bao mat"
	@echo "make asan     - build voi sanitizer"
	@echo "make clean    - xoa file build"
	@echo "make run      - chay chuong trinh"
	@echo "make test     - chay test"

debug:   CFLAGS += -g3 -O0 -DDEBUG
debug:   $(TARGET)

release: CFLAGS += -O2 -DNDEBUG -flto ...
release: $(TARGET)

/* Ca "debug" va "release" deu phu thuoc $(TARGET), va $(TARGET)
   dung MOT quy tac dich. Nhung dong "debug: CFLAGS += ..." lam
   CFLAGS co gia tri KHAC khi ban dung qua muc tieu "debug".

   make debug   -> CFLAGS = ...co ban... -g3 -O0 -DDEBUG
   make release -> CFLAGS = ...co ban... -O2 -DNDEBUG -flto ...

   Do la ly do khong can viet ba quy tac dich rieng cho ba cau
   hinh. Mot quy tac, ba bo co, chon bang ten muc tieu. */