自定义 ELF 文件中未定义的引用，但符号在文件符号表中定义

问：

我一直在尝试了解 x86-64 机器代码和 ELF 文件。为此，我编写了一些代码来生成一个包含一些机器代码的 ELF 文件。我使用一些我组装的机器代码（它只是打印一条消息并调用系统调用，接下来是自己学习组装机器代码）并编写了一个 C 程序来手动将正确的 ELF 标头/Section 标头/符号表等写入文件。nasmexit

现在我正在尝试将我的文件（其中包含单个函数）链接到另一个 elf 文件，我通过 C 代码生成该文件（）：gcctest.c

// does not work with or without "extern"
extern void hello();

void _start()
{
  hello();

  // exit system call
  asm(
    "movl $60,%eax;"
    "xorl %ebx,%ebx;"
    "syscall");
}

我的ELF文件的输出是（）：readelf -ahello.o

ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              REL (Relocatable file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          0 (bytes into file)
  Start of section headers:          64 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           0 (bytes)
  Number of program headers:         0
  Size of section headers:           64 (bytes)
  Number of section headers:         9
  Section header string table index: 8

Section Headers:
  [Nr] Name              Type             Address           Offset
       Size              EntSize          Flags  Link  Info  Align
  [ 0]                   NULL             0000000000000000  00000000
       0000000000000000  0000000000000000           0     0     0
  [ 1] .text             PROGBITS         0000000000000000  00000280
       0000000000000044  0000000000000000  AX       0     0     16
  [ 2] .rela.text        RELA             0000000000000000  000002c8
       0000000000000030  0000000000000018   I       6     1     8
  [ 3] .data             PROGBITS         0000000000000000  00000300
       0000000000000005  0000000000000000  WA       0     0     16
  [ 4] .bss              NOBITS           0000000000000000  00000310
       0000000000000080  0000000000000000   A       0     0     16
  [ 5] .rodata           PROGBITS         0000000000000000  00000310
       000000000000000d  0000000000000000   A       0     0     16
  [ 6] .symtab           SYMTAB           0000000000000000  00000320
       0000000000000150  0000000000000018           7    14     8
  [ 7] .strtab           STRTAB           0000000000000000  00000470
       0000000000000028  0000000000000000           0     0     1
  [ 8] .shstrtab         STRTAB           0000000000000000  00000498
       000000000000003f  0000000000000000           0     0     1
Key to Flags:
  W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
  L (link order), O (extra OS processing required), G (group), T (TLS),
  C (compressed), x (unknown), o (OS specific), E (exclude),
  l (large), p (processor specific)

There are no section groups in this file.

There are no program headers in this file.

There is no dynamic section in this file.

Relocation section '.rela.text' at offset 0x2c8 contains 2 entries:
  Offset          Info           Type           Sym. Value    Sym. Name + Addend
00000000001a  000500000001 R_X86_64_64       0000000000000000 .rodata + 0
000000000024  00050000000a R_X86_64_32       0000000000000000 .rodata + d

The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported.

Symbol table '.symtab' contains 14 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND 
     1: 0000000000000000     0 SECTION LOCAL  DEFAULT    1 
     2: 0000000000000000     0 SECTION LOCAL  DEFAULT    2 
     3: 0000000000000000     0 SECTION LOCAL  DEFAULT    3 
     4: 0000000000000000     0 SECTION LOCAL  DEFAULT    4 
     5: 0000000000000000     0 SECTION LOCAL  DEFAULT    5 
     6: 0000000000000000     0 SECTION LOCAL  DEFAULT    6 
     7: 0000000000000000     0 SECTION LOCAL  DEFAULT    7 
     8: 0000000000000000     0 SECTION LOCAL  DEFAULT    8 
     9: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS hello.c
    10: 0000000000000000    68 FUNC    GLOBAL DEFAULT    1 hello
    11: 0000000000000060    13 OBJECT  LOCAL  DEFAULT    5 msg
    12: 000000000000000d     8 NOTYPE  LOCAL  DEFAULT  ABS len
    13: 0000000000000050     5 OBJECT  GLOBAL DEFAULT    3 _test

No version information found in this file.

我已经编译了test.c

gcc -c -nostdlib -fno-asynchronous-unwind-tables test.c -o test.o

然后与 链接，不幸的是，这会产生ld test.o hello.o

ld: test.o: in function `_start':
test.c:(.text+0xa): undefined reference to `hello'

即使函数在 （请注意符号表中命名的条目，该条目位于第 1 节，该部分中，并且似乎具有正确的大小/类型/值/绑定）。hellohello.ohello.text

如果我以与编译相同的方式编译一个文件，这两个目标文件显然可以链接。此外，如果我将自己的 ELF 文件生成为可执行文件，则将函数重命名为它可以很好地执行。我已经用头撞墙一段时间了，我想知道两件事：显然我想知道我的ELF文件问题。但我也想知道将来如何调试此类问题。我尝试使用调试符号从源代码构建（克隆 GNU binutils 存储库），但我没有走得很远调试本身。void hello(){}test.chello.ohello_startldld

编辑：我已在此处上传了我的精灵文件： https://drive.google.com/file/d/1cRNr0VPAjkEbueuWFYwLYbpijVnLySqq/view?usp=sharing