https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94134
--- Comment #13 from Stephen Casner <casner at acm dot org> ---
(In reply to Stephen Casner from comment #9)
(Commenting on my own comment)
> 1. pdp11-aout does not have a .lcommon or .lcomm section, just .text, .data
> and .bss. But also I'm missing something about the concept of a
> NOSWITCH_SECTION that you can't switch to with an assembler directive -- how
> do you tell the assembler to assign a variable to that section if you don't
> emit a directive?
The a.out file format produced by the assembler or linker includes only the
.text, .data and .bss sections. However, that does not mean the compiler could
not pass a .comm or .lcomm directive to the assembler. I now understand those
and the NOSWITCH concept. In fact, I found that the Unix v6 cc produces the
.comm directive which I had not seen before:
# cat > static.c
int zero;
int one;
int main() {
static int two;
zero = 0;
one = 1;
two = 2;
}
# cc -S static.s static.c
# cat static.s
.globl _zero
.comm _zero,2
.globl _one
.comm _one,2
.globl _main
.text
_main:
~~main:
.bss
L2:.=.+2
.text
~two=L2
jsr r5,csv
clr _zero
mov $1,_one
mov $2,L2
L1:jmp cret
.globl
.data
#
So presumably the ASM_OUTPUT{_ALIGNED{,_DECL}_}_LOCAL functions could generate
.comm and .lcomm directives to be allocated to the .bss section by as. I don't
know if there is enough size information in the relocation section of the a.out
file to allow merging global .comm declarations.
