如何在交叉编译中解决crt0.o链接问题?

时间:2013-08-24 08:30:03

标签: gcc arm cross-compiling raspberry-pi crt

如何添加ctr0.o

我收到此错误:

yagarto-4.7.2/bin/arm-none-eabi-ld: cannot find crt0.o: No such file or directory
collect2: error: ld returned 1 exit status`

here编译非常简单的程序:

/* -- first.s */
/* This is a comment */
.global main /* 'main' is our entry point and must be global */
.func main   /* 'main' is a function */

main:          /* This is main */
    mov r0, #2 /* Put a 2 inside the register r0 */
    bx lr      /* Return from main */

我已经看过这两个帖子并没有得到任何完整而直截了当的答案:

  1. http://www.raspberrypi.org/phpBB3/viewtopic.php?t=50046
  2. What is the rationale behind removing crt0.o from gcc4.7.x?
  3. 我有这些文件,crt0和crtn有什么区别我不能用它?

    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/crtbegin.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/crtend.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/crti.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/crtn.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/crtbegin.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/crtend.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/crti.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/crtn.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v6m/crtbegin.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v6m/crtend.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v6m/crti.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v6m/crtn.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v7m/crtbegin.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v7m/crtend.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v7m/crti.o
    ./yagarto-4.7.2/lib/gcc/arm-none-eabi/4.7.2/thumb/v7m/crtn.o
    

    SO解决方案提供了一种不起作用的解决方法:

    arm-none-eabi-gcc -o first assembler_tutorial/chapter01/first.o -nostartfiles
    ./yagarto-4.7.2/bin/arm-none-eabi-ld: warning: cannot find entry symbol _start; defaulting to 0000000000008000
    

2 个答案:

答案 0 :(得分:10)

vectors.s

.globl _start
_start:
    mov sp,#0x8000
    bl main
hang: b hang

main.s

.globl main
main:
    mov r0,#2
    bx lr

memmap(链接描述文件)

MEMORY
{
    ram : ORIGIN = 0x8000, LENGTH = 0x10000
}
SECTIONS
{
    .text : { *(.text*) } > ram
    .bss : { *(.bss*) } > ram
}

命令

arm-none-eabi-as vectors.s -o vectors.o
arm-none-eabi-as main.s -o main.o
arm-none-eabi-ld vectors.o main.o -T memmap -o main.elf
arm-none-eabi-objdump -D main.elf > main.list
arm-none-eabi-objcopy main.elf -O binary main.bin

结果

main.elf:     file format elf32-littlearm


Disassembly of section .text:

00008000 <_start>:
    8000:   e3a0d902    mov sp, #32768  ; 0x8000
    8004:   eb000000    bl  800c <main>

00008008 <hang>:
    8008:   eafffffe    b   8008 <hang>

0000800c <main>:
    800c:   e3a00002    mov r0, #2
    8010:   e12fff1e    bx  lr

如果您想使用C而不是asm作为main

的main.c

int main ( void )
{
    return(2);
}

命令

arm-none-eabi-as vectors.s -o vectors.o
arm-none-eabi-gcc -Wall -Werror -O2 -nostdlib -nostartfiles -ffreestanding -c main.c -o main.o
arm-none-eabi-ld vectors.o main.o -T memmap -o main.elf
arm-none-eabi-objdump -D main.elf > main.list
arm-none-eabi-objcopy main.elf -O binary main.bin

结果

main.elf:     file format elf32-littlearm


Disassembly of section .text:

00008000 <_start>:
    8000:   e3a0d902    mov sp, #32768  ; 0x8000
    8004:   eb000000    bl  800c <main>

00008008 <hang>:
    8008:   eafffffe    b   8008 <hang>

0000800c <main>:
    800c:   e3a00002    mov r0, #2
    8010:   e12fff1e    bx  lr

我更喜欢使用main之外的函数名,因为有些编译器在看到函数名时会增加额外的行李。

vectors.s

.globl _start
_start:
    mov sp,#0x8000
    bl notmain
hang: b hang

的main.c

int notmain ( void )
{
    return(2);
}

结果

main.elf:     file format elf32-littlearm


Disassembly of section .text:

00008000 <_start>:
    8000:   e3a0d902    mov sp, #32768  ; 0x8000
    8004:   eb000000    bl  800c <notmain>

00008008 <hang>:
    8008:   eafffffe    b   8008 <hang>

0000800c <notmain>:
    800c:   e3a00002    mov r0, #2
    8010:   e12fff1e    bx  lr

答案 1 :(得分:1)

尝试编译STM32F4xx(Cortex M4)时遇到了同样的问题。

我抛弃Yagarto并转而使用GNU Tools ARM Embedded - 工具链(4.8_2014q2):

https://launchpad.net/gcc-arm-embedded

似乎适合我。