Improve Makefile for recursive invocation

Author: vacantron

Makefile

@@ -5,8 +5,9 @@ OPT_LEVEL := 0 1 2
 CFLAGS := -std=c99
 LDFLAGS := -lsemihost -lm
 
-SRC_DIR := src
-BUILD_DIR := build
+CURDIR := $(abspath $(dir $(lastword $(MAKEFILE_LIST))))
+SRC_DIR := $(CURDIR)/src
+BUILD_DIR := $(CURDIR)/build
 
 SRCS := \
   captcha.c \
@@ -43,31 +44,34 @@ ifneq ($(filter $(OPT_LEVEL), 2),)
 all: build-O2
 endif
 
+all:
+	$(Q)$(MAKE) -C src/asm-hello BUILD_DIR="$(BUILD_DIR)" RV32_EXT=$(RV32_EXT) OPT_LEVEL="$(OPT_LEVEL)" all
+
 include mk/common.mk
 include mk/toolchain.mk
 
 build-O0: $(addprefix $(BUILD_DIR)/$(RV32_EXT)/O0/,$(EXECUTABLES))
 
 $(BUILD_DIR)/$(RV32_EXT)/O0/%.elf: $(SRC_DIR)/%.c | build-toolchain
-	$(VECHO) "  RISCVCC\t$@\n"
+	$(VECHO) "  RISCVCC\t$(patsubst $(abspath $(SRC_DIR)/..)/%,%,$@)\n"
 	$(Q)$(CROSS_COMPILE) -o $@ -O0 $(CFLAGS) $< $(LDFLAGS)
 
 build-O1: $(addprefix $(BUILD_DIR)/$(RV32_EXT)/O1/,$(EXECUTABLES))
 
 $(BUILD_DIR)/$(RV32_EXT)/O1/%.elf: $(SRC_DIR)/%.c | build-toolchain
-	$(VECHO) "  RISCVCC\t$@\n"
+	$(VECHO) "  RISCVCC\t$(patsubst $(abspath $(SRC_DIR)/..)/%,%,$@)\n"
 	$(Q)$(CROSS_COMPILE) -o $@ -O1 $(CFLAGS) $< $(LDFLAGS)
 
 build-O2: $(addprefix $(BUILD_DIR)/$(RV32_EXT)/O2/,$(EXECUTABLES))
 
 $(BUILD_DIR)/$(RV32_EXT)/O2/%.elf: $(SRC_DIR)/%.c | build-toolchain
-	$(VECHO) "  RISCVCC\t$@\n"
+	$(VECHO) "  RISCVCC\t$(patsubst $(abspath $(SRC_DIR)/..)/%,%,$@)\n"
 	$(Q)$(CROSS_COMPILE) -o $@ -O2 $(CFLAGS) $< $(LDFLAGS)
 
 clean:
-	$(RM) -r $(BUILD_DIR)/$(RV32_EXT)/*
+	$(RM) -r $(foreach LEVEL,$(OPT_LEVEL),$(BUILD_DIR)/$(RV32_EXT)/O$(LEVEL)/*)
 
 distclean: clean
 	$(RM) -r $(BUILD_DIR)/*
 	$(RM) -r $(RISCV_TOOLCHAIN_DIR)/build/*
-	$(MAKE) -C $(RISCV_TOOLCHAIN_DIR) distclean
+	$(Q)$(MAKE) -C $(RISCV_TOOLCHAIN_DIR) distclean

src/asm-hello/Makefile

@@ -1,17 +1,64 @@
-include ../../mk/toolchain.mk
+RV32_EXT ?= rv32i
+OPT_LEVEL ?= 0 1 2
 
-ASFLAGS := -march=rv32i -mabi=ilp32
+ASFLAGS := -march=$(RV32_EXT) -mabi=ilp32
 LDFLAGS := --oformat=elf32-littleriscv
 
-.PHONY: all clean
+CURDIR := $(abspath $(dir $(lastword $(MAKEFILE_LIST))))
+SRC_DIR := $(CURDIR)
+
+# prevent lazy set if not providing initial value
+ifeq ($(BUILD_DIR),)
+  BUILD_DIR := $(CURDIR)/build
+endif
+
+SRCS := hello.S
+EXECUTABLES := hello.elf
+
+SHELL_HACK := $(shell mkdir -p $(foreach LEVEL,$(OPT_LEVEL),$(BUILD_DIR)/$(RV32_EXT)/O$(LEVEL)/asm-hello))
+
+.PHONY: all clean build-O0 build-O1 build-O2
+
+ifneq ($(filter $(OPT_LEVEL), 0),)
+all: build-O0
+endif
+
+ifneq ($(filter $(OPT_LEVEL), 1),)
+all: build-O1
+endif
+
+ifneq ($(filter $(OPT_LEVEL), 2),)
+all: build-O2
+endif
+
+include ../../mk/common.mk
+include ../../mk/toolchain.mk
+
+# RISC-V assembler doesn't support "-O" option currently
+
+build-O0: $(addprefix $(BUILD_DIR)/$(RV32_EXT)/O0/asm-hello/,$(EXECUTABLES))
+
+$(BUILD_DIR)/$(RV32_EXT)/O0/asm-hello/%.elf: $(SRC_DIR)/%.S | build-toolchain
+	$(VECHO) "  RISCVAS\t$(patsubst $(abspath $(BUILD_DIR)/..)/%.elf,%.o,$@)\n"
+	$(Q)$(RV32_PREFIX)as -o $(patsubst %.elf,%.o,$@) -R $(ASFLAGS) $<
+	$(VECHO) "  RISCVLD\t$(patsubst $(abspath $(BUILD_DIR)/..)/%,%,$@)\n"
+	$(Q)$(RV32_PREFIX)ld -o $@ -T $(SRC_DIR)/hello.ld -O0 $(LDFLAGS) $(patsubst %.elf,%.o,$@)
+
+build-O1: $(addprefix $(BUILD_DIR)/$(RV32_EXT)/O1/asm-hello/,$(EXECUTABLES))
 
-%.o: %.S
-	$(CROSS_COMPILE)as -R $(ASFLAGS) -o $@ $<
+$(BUILD_DIR)/$(RV32_EXT)/O1/asm-hello/%.elf: $(SRC_DIR)/%.S | build-toolchain
+	$(VECHO) "  RISCVAS\t$(patsubst $(abspath $(BUILD_DIR)/..)/%.elf,%.o,$@)\n"
+	$(Q)$(RV32_PREFIX)as -o $(patsubst %.elf,%.o,$@) -R $(ASFLAGS) $<
+	$(VECHO) "  RISCVLD\t$(patsubst $(abspath $(BUILD_DIR)/..)/%,%,$@)\n"
+	$(Q)$(RV32_PREFIX)ld -o $@ -T $(SRC_DIR)/hello.ld -O1 $(LDFLAGS) $(patsubst %.elf,%.o,$@)
 
-all: hello.elf
+build-O2: $(addprefix $(BUILD_DIR)/$(RV32_EXT)/O2/asm-hello/,$(EXECUTABLES))
 
-hello.elf: hello.o
-	 $(CROSS_COMPILE)ld -o $@ -T hello.ld $(LDFLAGS) $<
+$(BUILD_DIR)/$(RV32_EXT)/O2/asm-hello/%.elf: $(SRC_DIR)/%.S | build-toolchain
+	$(VECHO) "  RISCVAS\t$(patsubst $(abspath $(BUILD_DIR)/..)/%.elf,%.o,$@)\n"
+	$(Q)$(RV32_PREFIX)as -o $(patsubst %.elf,%.o,$@) -R $(ASFLAGS) $<
+	$(VECHO) "  RISCVLD\t$(patsubst $(abspath $(BUILD_DIR)/..)/%,%,$@)\n"
+	$(Q)$(RV32_PREFIX)ld -o $@ -T $(SRC_DIR)/hello.ld -O2 $(LDFLAGS) $(patsubst %.elf,%.o,$@)
 
 clean:
-	$(RM) hello.elf hello.o
+	$(RM) $(foreach LEVEL,$(OPT_LEVEL),$(BUILD_DIR)/$(RV32_EXT)/O$(LEVEL)/asm-hello/*)