From 3dbaad0a1f27b96462541e1189efe37ffa913e9a Mon Sep 17 00:00:00 2001
From: Albert Ou <albert@sifive.com>
Date: Tue, 13 Dec 2016 15:05:19 -0800
Subject: Refactor libc stubs into libwrap

The --wrap feature of GNU ld supports a cleaner framework for linking in
alternative implementations of libc functions without cpp hacks.
Place wrappers in separate object files to reduce static code size.
---
 bsp/env/common.mk | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

(limited to 'bsp/env/common.mk')

diff --git a/bsp/env/common.mk b/bsp/env/common.mk
index 8d91805..0f5e9a1 100644
--- a/bsp/env/common.mk
+++ b/bsp/env/common.mk
@@ -1,5 +1,13 @@
 # See LICENSE for license details.
 
+ifndef _SIFIVE_MK_COMMON
+_SIFIVE_MK_COMMON := # defined
+
+.PHONY: all
+all: $(TARGET)
+
+include $(BSP_BASE)/libwrap/libwrap.mk
+
 BOARD ?= freedom-e300-hifive1
 ENV_DIR = $(BSP_BASE)/env
 PLATFORM_DIR = $(ENV_DIR)/$(BOARD)
@@ -7,28 +15,32 @@ PLATFORM_DIR = $(ENV_DIR)/$(BOARD)
 ASM_SRCS += $(PLATFORM_DIR)/start.S
 ASM_SRCS += $(PLATFORM_DIR)/entry.S
 C_SRCS += $(PLATFORM_DIR)/init.c
-C_SRCS += $(ENV_DIR)/syscall.c
 
 LINKER_SCRIPT := $(PLATFORM_DIR)/link.lds
 
-INCLUDES += -I.
 INCLUDES += -I$(BSP_BASE)/include
 INCLUDES += -I$(ENV_DIR)
 INCLUDES += -I$(PLATFORM_DIR)
 
-CC := $(BSP_BASE)/../toolchain/bin/riscv32-unknown-elf-gcc
+TOOL_DIR = $(BSP_BASE)/../toolchain/bin
 
-LDFLAGS += -T $(LINKER_SCRIPT) -nostdlib -nostartfiles -lc -lgcc
+CC := $(TOOL_DIR)/riscv32-unknown-elf-gcc
+AR := $(TOOL_DIR)/riscv32-unknown-elf-ar
+
+LDFLAGS += -T $(LINKER_SCRIPT) -nostartfiles
 LDFLAGS += -L$(ENV_DIR)
 
-ASM_OBJS := $(patsubst %.S,%.o,$(ASM_SRCS))
-C_OBJS := $(patsubst %.c,%.o,$(C_SRCS))
+ASM_OBJS := $(ASM_SRCS:.S=.o)
+C_OBJS := $(C_SRCS:.c=.o)
 
 LINK_OBJS += $(ASM_OBJS) $(C_OBJS)
+LINK_DEPS += $(LINKER_SCRIPT)
+
+CLEAN_OBJS += $(TARGET) $(LINK_OBJS)
 
 CFLAGS += -g
 
-$(TARGET): $(LINK_OBJS) $(LINKER_SCRIPT)
+$(TARGET): $(LINK_OBJS) $(LINK_DEPS)
 	$(CC) $(CFLAGS) $(INCLUDES) $(LINK_OBJS) -o $@ $(LDFLAGS)
 
 $(ASM_OBJS): %.o: %.S $(HEADERS)
@@ -37,9 +49,8 @@ $(ASM_OBJS): %.o: %.S $(HEADERS)
 $(C_OBJS): %.o: %.c $(HEADERS)
 	$(CC) $(CFLAGS) $(INCLUDES) -c -o $@ $<
 
-all: $(TARGET)
-
+.PHONY: clean
 clean:
-	rm -f $(TARGET) $(LINK_OBJS)
+	rm -f $(CLEAN_OBJS)
 
-.PHONY: all clean
+endif # _SIFIVE_MK_COMMON
-- 
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