Jim,
Sorry for missing the information.
file evi.c:
register void* regVar asm ("r15");
int
main()
{
char *str = "Hello";
regVar = str;
return 0;
}
% gcc -v
Using built-in specs.
COLLECT_GCC=/tools/oss/packages/x86_64-centos7/gcc/9.3.0/bin/gcc
COLLECT_LTO_WRAPPER=/tools/oss/packages/x86_64-rhel7/gcc/9.3.0/bin/../libexec/gcc/x86_64-pc-linux-gnu/9.3.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../../gcc-9.3.0/configure
--prefix=/tools/oss/packages/x86_64-centos7/gcc/9.3.0 --with-gnu-as
--with-as=/tools/bin/as --with-gnu-ld --with-ld=/tools/bin/ld
--with-mpc=/tools/oss/packages/x86_64-centos7/mpc/1.0.3
--with-mpfr=/tools/oss/packages/x86_64-centos7/mpfr/3.1.2
--enable-languages=c,c++,objc --enable-symvers=gnu
Thread model: posix
gcc version 9.3.0 (GCC)
% gcc -g3 evi.c -o evi
% gdb evi
(gdb) list
1 register void* regVar asm ("r15");
2 int
3 main()
4 {
5 char *str = "Hello";
6 regVar = str;
7 return 0;
8 }
(gdb) b 7
Breakpoint 1 at 0x400502: file evi.c, line 7.
(gdb) r
Starting program: evi
Breakpoint 1, main () at evi.c:7
7 return 0;
(gdb) p regVar
Missing ELF symbol "regVar".
(gdb) p str
$1 = 0x400594 "Hello"
(gdb) p/x $r15
$2 = 0x400594
(gdb) p (char *)$r15
$3 = 0x400594 "Hello"
I tried it for ARM architecture as well with the same result.
Thanks,
Yuri
On Fri, Aug 13, 2021 at 1:28 PM Jim Wilson <jimw@xxxxxxxxxx> wrote:
> On Wed, Aug 11, 2021 at 3:50 PM Yuri Karlsbrun via Gcc-help <
> gcc-help@xxxxxxxxxxx> wrote:
>
>> By default gcc register variables are missing from symbol table, and not
>> visible by gdb. Is there a way to save information about register
>> variables
>> in the object file, and make it visible by gdb?
>>
>
> A small testcase to reproduce would be useful to understand what you are
> talking about. Are you using register or asm("register")? Is this a local
> or global? What target are you compiling for? What compiler options are
> you using? What debug info format are you using? Dwarf, stabs? Why do
> you think the debug info is missing? Can you show some gdb output? If you
> are using stabs, then that is probably why it is failing for you. Use
> dwarf instead.
>
> JIm
>
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