* gas section alignment less than 4 bytes
@ 2023-07-03 20:56 Vincent Rivière
2023-07-03 21:03 ` Andreas Schwab
2023-07-04 11:08 ` Nick Clifton
0 siblings, 2 replies; 3+ messages in thread
From: Vincent Rivière @ 2023-07-03 20:56 UTC (permalink / raw)
To: binutils
Hi,
I wonder if there is a way for gas to generate an object with section
alignment less than 4.
$ echo nop | m68k-elf-as -o a.o
$ m68k-elf-objdump -h a.o
a.o: file format elf32-m68k
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00000002 00000000 00000000 00000034 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
1 .data 00000000 00000000 00000000 00000038 2**2
CONTENTS, ALLOC, LOAD, DATA
2 .bss 00000000 00000000 00000000 00000038 2**2
I would like to get Algn = 2**1 for all sections.
Is it possible to achieve that? How?
Cheers,
--
Vincent Rivière
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: gas section alignment less than 4 bytes
2023-07-03 20:56 gas section alignment less than 4 bytes Vincent Rivière
@ 2023-07-03 21:03 ` Andreas Schwab
2023-07-04 11:08 ` Nick Clifton
1 sibling, 0 replies; 3+ messages in thread
From: Andreas Schwab @ 2023-07-03 21:03 UTC (permalink / raw)
To: Vincent Rivière; +Cc: binutils
On Jul 03 2023, Vincent Rivière wrote:
> I wonder if there is a way for gas to generate an object with section
> alignment less than 4.
It's hardcoded, see md_begin.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: gas section alignment less than 4 bytes
2023-07-03 20:56 gas section alignment less than 4 bytes Vincent Rivière
2023-07-03 21:03 ` Andreas Schwab
@ 2023-07-04 11:08 ` Nick Clifton
1 sibling, 0 replies; 3+ messages in thread
From: Nick Clifton @ 2023-07-04 11:08 UTC (permalink / raw)
To: Vincent Rivière, binutils
Hi Vincent,
> I wonder if there is a way for gas to generate an object with section alignment less than 4.
If you do not mind the section having a name other than .text, then sure:
$ cat fred.s
.section foo, "ax"
nop
$ m68k-elf-as fred.s -o fred.o
$ m68k-elf-objdump -h fred.o
[...]
3 foo 00000002 00000000 00000000 00000034 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
> I would like to get Algn = 2**1 for all sections.
> Is it possible to achieve that? How?
If you want to change the alignment of all of the sections, then
you cannot do it using gas, but you can using objcopy:
$ echo nop | m68k-elf-as -o a.o
$ mk68k-elf-objcopy --set-section-alignment=\*=2 a.o b.o
$ m68k-elf-objdump -h b.o
[...]
0 .text 00000002 00000000 00000000 00000034 2**1
CONTENTS, ALLOC, LOAD, READONLY, CODE
1 .data 00000000 00000000 00000000 00000036 2**1
CONTENTS, ALLOC, LOAD, DATA
2 .bss 00000000 00000000 00000000 00000036 2**1
ALLOC
Cheers
Nick
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-07-03 20:56 gas section alignment less than 4 bytes Vincent Rivière
2023-07-03 21:03 ` Andreas Schwab
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