linker script, /DISCARD/ section and SHT_GROUP

[Serge Guelton <sguelton at redhat dot com>]

Hi folks,

While digging in the interaction between linker script's /DISCARD/ section and
groups, I found the following behavior:

$ gcc -c a.s
$ readelf -WS a.o
[ bunch of sections, including ]
[ 5] .myanote.foo      NOTE            0000000000000000 000054 000001 00  AG  0  0  1
[ 6] .mytext.foo       PROGBITS        0000000000000000 000055 000001 00 AXG  0  0  1

$ ld -T a.script  -o a2.o a.o
$ readelf -WS a.o
[ bunch of sections, including ]
[ 6] .mytext.foo       PROGBITS        0000000000000000 000055 000001 00 AXG  0  0  1

where :

<< a.script >>

SECTIONS { /DISCARD/ : { *(.myanote.foo) }}

<< a.s >>

.globl anote_foo, foo, bss_foo, note_foo

.section .myanote.foo,"aG",@note,foo,comdat
anote_foo:
.byte 0

.section .mytext.foo,"axG",@progbits,foo,comdat
foo:
.byte 0

.section .mybss.foo,"awG",@nobits,foo,comdat
bss_foo:
.byte 0

.section .mynote.foo,"G",@note,foo,comdat
note_foo:
.byte 0

.section .mynote.bar,"",@note


I find this behavior relatively strange with respect to group semantic: we end
up with a group with one of its member stripped, and the others happily living
around.

Surely, the /DISCARD/ section is incomplete, but I would have expected a
warning, if not an error, in that case.

Is my understanding correct or am I missing something?