How to handle different sizes of pointers in GDB?

Hi,

I'm porting GDB to a new architecture. Now the application for this
architecture has two kinds of pointers in different sizes, one is 32-bit
and one is 64-bit. I have done the following things:

1. I use set_gdbarch_addr_bit(gdbarch,64) and
set_gdbarch_ptr_bit(gdbarch,64) to set both the addresses and the pointers
64-bit.
2. I tried to add a DW_AT_byte_size and DW_AT_address_class information
under each of the pointer type with DW_TAG_pointer_type in the compiler for
my new architecture.

My program can be like this:

int strlen32(const char *s) { /* s is 32-bit ... */ }
int strlen64(const _PTR64 char *s) { /* s is 64-bit ... */ }

However, GDB doesn't seem to get the correct type when printing the frame
arguments in read_frame_arg(), when I debug into strlen32, GDB can make the
GDB server crash because GDB is trying to read from a 64-bit address, which
it thinks is the value of s. And when I debug this GDB read_frame_arg(), I
see the type length of s in strlen32 is still 8 bytes.

So is there anything missing to make GDB use the type length information
from the DWARF debugging info?

Regards,
Iru