[GOLD] -Ttext does not relocate as expected

[Ian Lance Taylor]

On Wed, Mar 20, 2013 at 5:21 PM, ryan <stdstack@gmail.com> wrote:
> Not sure whether this is a bug or not. When I'm writing a simple hello
> world boot loader, I tried to relocate the text section to 0x7c00 for
> convention. The assembly code is attached. I used the following
> command to compile it:
>> gcc -m32 -nostdinc -c -o boot.o boot.S
>> ld -m elf_i386 -N -e start -Ttext 0x7c00 -o boot.out boot.o
>> objdump -S boot.out > boot.asm
>> ...
>
> It doesn't work as expected. Then I checked boot.asm the actual start
> address is 0x8c00 instead of 0x7c00.
>> Disassembly of section .text:
>> 00008c00 <start>:
>>    8c00: fc                   cld
>>    8c01: 31 c0                 xor    %eax,%eax
>>    ...
>
> It took me a while to realize in my system, I replaced the default
> `ld' with `ld.gold'. So `ld' in the above command is actually
> `ld.gold'. After I changed it back to use the default `ld', the start
> address become 7c00 as expected. Does anyone has a clue why it's like
> this?


For GNU ld the -Ttext option sets the address of the .text section.
For gold the -Ttext option sets the address of the text segment.  If
your .text section is not the first section in your text segment, then
the results will differ.

Ian