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From: "casner at acm dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/94134] pdp11-aout puts initial variable into .text section rather than .data
Date: Wed, 11 Mar 2020 23:43:53 +0000 [thread overview]
Message-ID: <bug-94134-4-fZOd6aHDf0@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-94134-4@http.gcc.gnu.org/bugzilla/>
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.
next prev parent reply other threads:[~2020-03-11 23:43 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-11 6:52 [Bug target/94134] New: " casner at acm dot org
2020-03-11 7:05 ` [Bug target/94134] " casner at acm dot org
2020-03-11 7:32 ` pinskia at gcc dot gnu.org
2020-03-11 7:34 ` pinskia at gcc dot gnu.org
2020-03-11 8:26 ` jakub at gcc dot gnu.org
2020-03-11 14:48 ` jakub at gcc dot gnu.org
2020-03-11 14:52 ` jakub at gcc dot gnu.org
2020-03-11 16:57 ` pkoning at gcc dot gnu.org
2020-03-11 17:37 ` jakub at gcc dot gnu.org
2020-03-11 20:14 ` casner at acm dot org
2020-03-11 20:19 ` casner at acm dot org
2020-03-11 21:10 ` pkoning at gcc dot gnu.org
2020-03-11 23:18 ` casner at acm dot org
2020-03-11 23:43 ` casner at acm dot org [this message]
2020-03-17 18:57 ` cvs-commit at gcc dot gnu.org
2020-09-17 14:24 ` cvs-commit at gcc dot gnu.org
2020-09-17 17:18 ` jakub at gcc dot gnu.org
2020-09-18 5:27 ` casner at acm dot org
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