Re: [PATCH] Fix target architecture address size inside gdbarch structure

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2018-10-16 08:03, Denis Dmitriev wrote:
> Hi all,
> GDB can't get information about instructions when debugging 
> mips:octeon2
> architecture.
> The problem is that the gdbarch structure contains the wrong address 
> size
> for target architecture (gdbarch->addr_bit, 32).
> However, in the same structure there is data settings for the target
> architecture (mips:octeon2) which indicate the correct address size
> (gdbarch->bfd_arch_info->bits_per_address, 64).
> This patch fixes creation gdbarch structure. Now the address size is 
> taken
> directly from the settings (gdbarch->bfd_arch_info).

Hi Denis,

This file (gdbarch.c) is generated from gdbarch.sh, so it can't be 
modified directly.  What you see here:

   gdbarch->addr_bit = gdbarch_ptr_bit (gdbarch);

is the result from the default value of the addr_bit property in 
gdbarch.sh:

402 v;int;addr_bit;;;8 * sizeof (void*);0;gdbarch_ptr_bit (gdbarch);

So if any modification needs to be done here, it needs to be in 
gdbarch.sh.

However, I tried generating an executable with:

$ mips64el-linux-gnuabi64-gcc --versio
mips64el-linux-gnuabi64-gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 
20160609
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is 
NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR 
PURPOSE.
$ mips64el-linux-gnuabi64-gcc test.c -o test

And the resulting addr_bit and ptr_bit in gdb are both 64.  From you 
explanations, I get that the value you get for ptr_bit is 32.  Is this 
value the right one, or it should be 64?

Could you share how you generate you executable, with what toolchain, 
etc?

Simon