On Fri, Jan 13, 2023 at 05:44:15PM +0000, Srinath Parvathaneni via Gcc-patches
wrote:
> Hello,
>
> This patch teaches the DWARF support in gcc about RA_AUTH_CODE pseudo
> hard-register and also
> updates the ".save", ".cfi_register", ".cfi_offset", ".cfi_restore"
> directives accordingly.
> This patch also adds support to emit ".pacspval" directive when "pac ip, lr,
> sp" instruction
> in generated in the assembly.
>
> RA_AUTH_CODE register number is 107 and it's dwarf register number is 143.
I'm afraid increasing number of DWARF registers is ABI incompatible change.
E.g. libgcc __frame_state_for function fills in:
typedef struct frame_state
{
void *cfa;
void *eh_ptr;
long cfa_offset;
long args_size;
long reg_or_offset[PRE_GCC3_DWARF_FRAME_REGISTERS+1];
unsigned short cfa_reg;
unsigned short retaddr_column;
char saved[PRE_GCC3_DWARF_FRAME_REGISTERS+1];
} frame_state;
structure, where PRE_GCC3_DWARF_FRAME_REGISTERS defaults to
__LIBGCC_DWARF_FRAME_REGISTERS__, which is defined to
DWARF_FRAME_REGISTERS, which defaults to FIRST_PSEUDO_REGISTER.
So, changing FIRST_PSEUDO_REGISTER is an ABI change unless you arrange for
PRE_GCC3_DWARF_FRAME_REGISTERS to be defined to the old value.
Jakub
