"Andre Vieira (lists)" <andre.simoesdiasvie...@arm.com> writes:
> This patch makes sure we do not give ABI change diagnostics for the ABI
> breaks of GCC 9, 13 and 14 for any type involving _BitInt(N), since that
> type did not exist before this GCC version.
>
> ChangeLog:
>
> * config/aarch64/aarch64.cc (bitint_or_aggr_of_bitint_p): New function.
> (aarch64_layout_arg): Don't emit diagnostics for types involving
> _BitInt(N).
>
> diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
> index
> 1ea84c8bd7386e399f6ffa3a5e36408cf8831fc6..b68cf3e7cb9a6fa89b4e5826a39ffa11f64ca20a
> 100644
> --- a/gcc/config/aarch64/aarch64.cc
> +++ b/gcc/config/aarch64/aarch64.cc
> @@ -6744,6 +6744,33 @@ aarch64_function_arg_alignment (machine_mode mode,
> const_tree type,
> return alignment;
> }
>
> +/* Return true if TYPE describes a _BitInt(N) or an angreggate that uses the
> + _BitInt(N) type. These include ARRAY_TYPE's with an element that is a
> + _BitInt(N) or an aggregate that uses it, and a RECORD_TYPE or a UNION_TYPE
> + with a field member that is a _BitInt(N) or an aggregate that uses it.
> + Return false otherwise. */
> +
> +static bool
> +bitint_or_aggr_of_bitint_p (tree type)
> +{
> + if (!type)
> + return false;
> +
> + if (TREE_CODE (type) == BITINT_TYPE)
> + return true;
> +
> + /* If ARRAY_TYPE, check it's element type. */
> + if (TREE_CODE (type) == ARRAY_TYPE)
> + return bitint_or_aggr_of_bitint_p (TREE_TYPE (type));
> +
> + /* If RECORD_TYPE or UNION_TYPE, check the fields' types. */
> + if (RECORD_OR_UNION_TYPE_P (type))
> + for (tree field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
> + if (bitint_or_aggr_of_bitint_p (TREE_TYPE (field)))
> + return true;
> + return false;
> +}
> +
> /* Layout a function argument according to the AAPCS64 rules. The rule
> numbers refer to the rule numbers in the AAPCS64. ORIG_MODE is the
> mode that was originally given to us by the target hook, whereas the
> @@ -6767,12 +6794,6 @@ aarch64_layout_arg (cumulative_args_t pcum_v, const
> function_arg_info &arg)
> if (pcum->aapcs_arg_processed)
> return;
>
> - bool warn_pcs_change
> - = (warn_psabi
> - && !pcum->silent_p
> - && (currently_expanding_function_start
> - || currently_expanding_gimple_stmt));
> -
> /* HFAs and HVAs can have an alignment greater than 16 bytes. For example:
>
> typedef struct foo {
> @@ -6907,6 +6928,18 @@ aarch64_layout_arg (cumulative_args_t pcum_v, const
> function_arg_info &arg)
> && (!alignment || abi_break_gcc_9 < alignment)
> && (!abi_break_gcc_13 || alignment < abi_break_gcc_13));
>
> +
> + bool warn_pcs_change
> + = (warn_psabi
> + && !pcum->silent_p
> + && (currently_expanding_function_start
> + || currently_expanding_gimple_stmt)
> + /* warn_pcs_change is currently used to gate diagnostics in case of
> + abi_break_gcc_{9,13,14}. These however, do not apply to _BitInt(N)
> + types as they were only introduced in GCC 14. */
> + && (!type || !bitint_or_aggr_of_bitint_p (type)));
How about making this a new variable such as:
/* _BitInt(N) was only added in GCC 14. */
bool warn_pcs_change_le_gcc14
= (warn_psabi && !bitint_or_aggr_of_bitint_p (type);
(and keeping warn_pcs_change where it is). In principle, warn_pcs_change
is meaningful for any future ABI breaks, and we might forget that it
excludes bitints. The name is just a suggestion.
OK with that change, thanks.
Richard
> +
> +
> /* allocate_ncrn may be false-positive, but allocate_nvrn is quite
> reliable.
> The following code thus handles passing by SIMD/FP registers first. */
>
> @@ -21266,19 +21299,25 @@ aarch64_gimplify_va_arg_expr (tree valist, tree
> type, gimple_seq *pre_p,
> rsize = ROUND_UP (size, UNITS_PER_WORD);
> nregs = rsize / UNITS_PER_WORD;
>
> - if (align <= 8 && abi_break_gcc_13 && warn_psabi)
> + if (align <= 8
> + && abi_break_gcc_13
> + && warn_psabi
> + && !bitint_or_aggr_of_bitint_p (type))
> inform (input_location, "parameter passing for argument of type "
> "%qT changed in GCC 13.1", type);
>
> if (warn_psabi
> && abi_break_gcc_14
> - && (abi_break_gcc_14 > 8 * BITS_PER_UNIT) != (align > 8))
> + && (abi_break_gcc_14 > 8 * BITS_PER_UNIT) != (align > 8)
> + && !bitint_or_aggr_of_bitint_p (type))
> inform (input_location, "parameter passing for argument of type "
> "%qT changed in GCC 14.1", type);
>
> if (align > 8)
> {
> - if (abi_break_gcc_9 && warn_psabi)
> + if (abi_break_gcc_9
> + && warn_psabi
> + && !bitint_or_aggr_of_bitint_p (type))
> inform (input_location, "parameter passing for argument of type "
> "%qT changed in GCC 9.1", type);
> dw_align = true;
