C 到 ASM 增量导致段错误

Question

我有以下 C 程序：

#include <stdio.h>

int main() {
    int i = 0;
    int N = 10;
    while(i < N) {
        printf("counting to %d: %d", N, i);
        //i = i + 1;
    }
    return 0;
}

我想先将它编译成汇编，然后再编译成二进制以供教学使用。因此，我发出以下命令：

$ gcc -S count.c -o count.s
$ as -o count.o count.s
$ ld -o count -e main -dynamic-linker /lib64/ld-linux-x86-64.so.2 /usr/lib/x86_64-linux-gnu/libc.so count.o -lc

它们分别将 C 编译为程序集，assemble 将程序集编译为二进制文件，然后 link 包含 printf 函数的库。

这行得通。输出：

counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0counting to 10: 0

等等，直到我 ctrl-c 程序。

但是，当我取消注释 i = i + 1 行时：

Segmentation fault (core dumped)

这里出了什么问题？

更新：这里是 count.s（包括 i = i + 1 行）

    .file   "count.c"
    .text
    .section    .rodata
.LC0:
    .string "counting to %d: %d"
    .text
    .globl  main
    .type   main, @function
main:
.LFB0:
    .cfi_startproc
    pushq   %rbp
    .cfi_def_cfa_offset 16
    .cfi_offset 6, -16
    movq    %rsp, %rbp
    .cfi_def_cfa_register 6
    subq    , %rsp
    movl    [=14=], -8(%rbp)
    movl    , -4(%rbp)
    jmp .L2
.L3:
    movl    -8(%rbp), %edx
    movl    -4(%rbp), %eax
    movl    %eax, %esi
    leaq    .LC0(%rip), %rdi
    movl    [=14=], %eax
    call    printf@PLT
    addl    , -8(%rbp)
.L2:
    movl    -8(%rbp), %eax
    cmpl    -4(%rbp), %eax
    jl  .L3
    movl    [=14=], %eax
    leave
    .cfi_def_cfa 7, 8
    ret
    .cfi_endproc
.LFE0:
    .size   main, .-main
    .ident  "GCC: (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0"
    .section    .note.GNU-stack,"",@progbits

Answer 1

如果你在Linux64位的main函数末尾添加：

     mov eax, 60   
     xor edi, edi  
     syscall

在 linux 32

    mov  eax  1
    xor ebx,ebx  
    int 0x80

Answer 2

下面的内容对我来说在 Ubuntu 20 上工作得很好（摘自 Ciro Santilli 在 Linking a C program directly with ld fails with undefined reference to `__libc_csu_fini` 的回答）。

gcc -S count.c -o count.s
as -o count.o count.s
ld -o count -dynamic-linker /lib64/ld-linux-x86-64.so.2 /usr/lib/x86_64-linux-gnu/crt1.o /usr/lib/x86_64-linux-gnu/crti.o -L/usr/lib/gcc/x86_64-linux-gnu/4.8/ -lc count.o /usr/lib/x86_64-linux-gnu/crtn.o

C 到 ASM 增量导致段错误

C to ASM increment causes Segfault

c

assembly

gcc

crt

segmentation-fault