如何解决交叉编译中的crt0.o链接问题？

Question

如何添加ctr0.o？

我得到这个错误：

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` 

而从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 */ 

我已经看到了这2个线程，并没有得到任何全面和直接的答案：

1. http://www.raspberrypi.org/phpBB3/viewtopic.php?t=50046
2. What is the rationale behind removing crt0.o from gcc4.7.x?

我有这些文件，crt0和crtn之间有什么区别我不能使用它吗？

./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 

的SO溶液给出一种解决方法不工作或者：

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 

Answer 1

vectors.s

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

main.s

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

MEMMAP（接头脚本）

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 

如果你想用C代替ASM主然后

的main.c

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

个命令

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 

我喜欢用比主以外的功能名称，因为一些编译器添加额外的行李，当他们看到函数名。

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 

Answer 2

我有同样的问题，试图编译STM32F4xx（皮质M4）。

我抛弃Yagarto并切换到使用GNU工具ARM嵌入式 - 工具链（4.8_2014q2）：

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

似乎为我工作。