This patch makes the ABI code ignore zero-sized [[no_unique_address]]
fields when deciding whether something is a HFA or HVA.
As things stood, we'd get two sets of -Wpsabi warnings, one when
trying to decide whether something was an SVE function, and another
when actually processing the function definition or function call.
The patch therefore makes aapcs_vfp_sub_candidate honour the
CUMULATIVE_ARGS "silent_p" flag where applicable.
This doesn't stop all duplicate warnings for parameters, and I suspect
we'll get duplicate warnings for return values too, but it should be
better than nothing.
2020-04-29 Richard Sandiford <richard.sandiford@arm.com>
gcc/
* config/aarch64/aarch64.c (aarch64_function_arg_alignment): Add a
comment explaining why we consider even zero-sized fields.
(WARN_PSABI_EMPTY_CXX17_BASE): New constant.
(WARN_PSABI_NO_UNIQUE_ADDRESS): Likewise.
(aapcs_vfp_sub_candidate): Replace the boolean pointer parameter
avoid_cxx17_empty_base with a pointer to a bitmask. Ignore fields
whose DECL_FIELD_ABI_IGNORED bit is set when determining whether
something actually is a HFA or HVA. Record whether we see a
[[no_unique_address]] field that previous GCCs would not have
ignored in this way.
(aarch64_vfp_is_call_or_return_candidate): Add a parameter to say
whether diagnostics should be suppressed. Update the calls to
aapcs_vfp_sub_candidate and report a -Wpsabi warning for the
[[no_unique_address]] case.
(aarch64_return_in_msb): Update call accordingly, never silencing
diagnostics.
(aarch64_function_value): Likewise.
(aarch64_return_in_memory_1): Likewise.
(aarch64_init_cumulative_args): Likewise.
(aarch64_gimplify_va_arg_expr): Likewise.
(aarch64_pass_by_reference_1): Take a CUMULATIVE_ARGS pointer and
use it to decide whether arch64_vfp_is_call_or_return_candidate
should be silent.
(aarch64_pass_by_reference): Update calls accordingly.
(aarch64_vfp_is_call_candidate): Use the CUMULATIVE_ARGS argument
to decide whether arch64_vfp_is_call_or_return_candidate should be
silent.
gcc/testsuite/
* g++.target/aarch64/no_unique_address_1.C: New test.
* g++.target/aarch64/no_unique_address_2.C: Likewise.
