Code in .subsection 0 should be prior to .subsection 1

[Jan Beulich]

On 24.11.2025 11:02, Georg-Johann Lay via Binutils wrote:
> So I have problems grasping why code in .subsection 1
> is located PRIOR to code in .subsection 0:
> 
> ;; init.S
> .section .init2,"ax",@progbits
> .subsection 0
> .type __init_sp,@function
> .global __init_sp
> __init_sp:
>      ldi r22, 0
> 
> ;; main.S
> .section .init2,"ax",@progbits
> .subsection 1
>      ldi r22, 1
> .global __init_sp

Sub-sections are an assembler-internal thing, i.e. that information is lost
by the time the object file is built. Once again you could observe this
yourself when looking at the dump of the generate objects, where you will
see no trace of sub-sections.

Jan

> So the expected disassembly is
> 
> ldi r22, 0  ; .subsection 0
> ldi r22, 1  ; .subsection 1
> 
> But when I run
> 
> avr-ld --version | head -1
> avr-as main.S -o main.o
> 
> avr-as init.S -o init.o
> avr-ar cru libinit.a init.o
> avr-ranlib libinit.a
> 
> avr-ld main.o -o main.elf -L. -linit
> avr-objdump -d main.elf
> 
> The output is:
> 
> GNU ld (GNU Binutils) 2.45.50.20250718
> 
> main.elf:     file format elf32-avr
> 
> 
> Disassembly of section .text:
> 
> 00000000 <__ctors_end>:
>     0:	61 e0       	ldi	r22, 0x01	; 1
> 
> 00000002 <__init_sp>:
>     2:	60 e0       	ldi	r22, 0x00	; 0
> 
> The .init2 section is part of text and mentioned in the
> default ld script:
> 
>    .text   :
>    {
>      ....
>      *(.init2)  /* Clear __zero_reg__, set up stack pointer.  */
>      KEEP (*(.init2))
>      ....
>    } > text
> 
> What am I doing / understanding wrong?
> Is this a bug?
> 
> Johann
>