On Tue, Aug 06, 2024 at 03:07:44PM +0100, Matthieu Longo wrote:
> On AArch64, the RA state informs the unwinder whether the return address
> is mangled and how, or not. This information is encoded in a boolean in
> the CFI row. This binary approach prevents from expressing more complex
> configuration, as it is the case with PAuth_LR introduced in Armv9.5-A.
>
> This patch addresses this limitation by replacing the boolean by an enum.
Formatting nits.
>
> gcc/ChangeLog:
>
> * dwarf2cfi.cc
> (struct dw_cfi_row): Declare a new enum type to replace ra_mangled.
> (cfi_row_equal_p): Use ra_state instead of ra_mangled.
> (dwarf2out_frame_debug_cfa_negate_ra_state): Same.
> (change_cfi_row): Same.
> ---
> gcc/dwarf2cfi.cc | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/gcc/dwarf2cfi.cc b/gcc/dwarf2cfi.cc
> index 6c80e0b17bd..023f61fb712 100644
> --- a/gcc/dwarf2cfi.cc
> +++ b/gcc/dwarf2cfi.cc
> @@ -57,6 +57,15 @@ along with GCC; see the file COPYING3. If not see
> #define DEFAULT_INCOMING_FRAME_SP_OFFSET INCOMING_FRAME_SP_OFFSET
> #endif
>
> +
> +/* Signing method used for return address authentication.
> + (AArch64 extension)*/
Dot and two spaces missing before */
> +typedef enum
> +{
> + RA_no_signing = 0x0,
> + RA_signing_SP = 0x1,
> +} RA_signing_method_t;
I think it should be ra_* and *_sp
> @@ -1556,8 +1565,11 @@ dwarf2out_frame_debug_cfa_negate_ra_state (void)
> {
> dw_cfi_ref cfi = new_cfi ();
> cfi->dw_cfi_opc = DW_CFA_AARCH64_negate_ra_state;
> + cur_row->ra_state =
> + (cur_row->ra_state == RA_no_signing)
> + ? RA_signing_SP
> + : RA_no_signing;
This is wrongly formatted. = shouldn't be at the end of line.
Better
cur_row->ra_state
= (cur_row->ra_state == ra_no_signing
? ra_signing_sp : ra_no_signing);
Jakub
