Makefile

# Mostly generic makefile to build all c/c++/asm files in a directory tree
# Adapted from Job Vranish's: https://spin.atomicobject.com/2016/08/26/makefile-c-projects/
# Mark Nelson, 2/2021

# Note: Went this route after fighting linker errors related to C++ ABI issues,
# trying to link with ALE built as library.

TARGET_EXEC ?= countstates

BUILD_DIR ?= build
SRC_DIRS ?= .

SRCS := $(shell find $(SRC_DIRS) -name '*.cpp' -or -name '*.cc' -or -name '*.cxx' -or -name '*.c' -or -name '*.s')
OBJS := $(SRCS:%=$(BUILD_DIR)/%.o)
DEPS := $(OBJS:.o=.d)

INC_DIRS := $(shell find $(SRC_DIRS) -type d)
INC_FLAGS := $(addprefix -I,$(INC_DIRS))

CPPFLAGS ?= $(INC_FLAGS) -MMD -MP -O2 #-march=native -flto
CXXFLAGS ?= -std=c++17
LDFLAGS += -lz -lm -lpthread

$(BUILD_DIR)/$(TARGET_EXEC): $(OBJS)
	$(CXX) $(OBJS) -o $@ $(LDFLAGS)

# assembly
$(BUILD_DIR)/%.s.o: %.s
	$(MKDIR_P) $(dir $@)
	$(AS) $(ASFLAGS) -c $< -o $@

# c source
$(BUILD_DIR)/%.c.o: %.c
	$(MKDIR_P) $(dir $@)
	$(CC) $(CPPFLAGS) $(CFLAGS) -c $< -o $@

# c++ source
$(BUILD_DIR)/%.cpp.o: %.cpp
	$(MKDIR_P) $(dir $@)
	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c $< -o $@
$(BUILD_DIR)/%.cxx.o: %.cxx
	$(MKDIR_P) $(dir $@)
	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c $< -o $@
$(BUILD_DIR)/%.cc.o: %.cc
	$(MKDIR_P) $(dir $@)
	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c $< -o $@

.PHONY: clean

clean:
	$(RM) -r $(BUILD_DIR)

-include $(DEPS)

MKDIR_P ?= mkdir -p