C++ 在NASM中链接Linux共享库时出错'；将R_ X86_64_；foo'；

我目前正在重新编写NASM x64中标准C库中的一些函数.目前我只有两项职能:

strlen:

bits 64

section .text
    global  strlen
        strlen:
            xor rbx, rbx
            jmp strlen_loop

        strlen_loop:
            cmp byte [rdi + rbx], 0
            je strlen_ret
            inc rbx
            jmp strlen_loop

        strlen_ret:
            mov rax, rbx
            ret

putstr:

bits 64

extern strlen

STDOUT equ 1

section .text
    global putstr
        putstr:
            call strlen
            mov rdx, rax
            xor rax, rax
            mov rdi, STDOUT
            syscall
            ret

以下是生成文件:

CC      =   nasm
CFLAGS  =   -f elf64
SRC     =   $(wildcard src/*.asm)
OBJ     =   $(SRC:.asm=.o)
NAME    =   minilibc.so

all: $(NAME)

$(NAME): $(OBJ)
    ld -fPIC -shared -o $(NAME) $(OBJ) -nostdlib

%.o: %.asm
    $(CC) $(CFLAGS) $< -o $@

clean:
    rm -f $(OBJ)

fclean: clean
    rm -f $(NAME)

re: fclean all

test: re
    gcc -o test/test test/main.c
    LD_PRELOAD=./minilibc.so ./test/test

.PHONY: all clean fclean re

以及测试代码:

#include <stdio.h>

extern size_t putstr(const char *str);

int main(void)
{
    const char *str = "Hello, World!\n";
    putstr(str);
    return (0);
}

下面是我得到的错误:

rm -f src/putstr.o src/strlen.o
rm -f minilibc.so
nasm -f elf64 src/putstr.asm -o src/putstr.o
nasm -f elf64 src/strlen.asm -o src/strlen.o
ld -fPIC -shared -o minilibc.so src/putstr.o src/strlen.o -nostdlib
ld: src/putstr.o: attention: readdress on "strlen" in read-only ".text" section
ld: src/putstr.o: readdressing R_X86_64_PC32 to symbol "strlen" cannot be used when creating a shared object; recompile with -fPIC
ld: final link edit failed: wrong value
make: *** [Makefile:10: minilibc.so] Error 1

LD似乎在告诉我在PIC模式下重新编译，我已经在这样做了，那么我的函数与GLIBC函数同名是不是有问题？但是，我在没有标准库的情况下进行编译.