From b5377928a2a5cd2a79eda59e2eba7d0511bf7566 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Fri, 1 Mar 2024 15:42:52 +0100 Subject: [PATCH] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR114136] On Tue, Feb 27, 2024 at 04:41:32PM +0000, Richard Earnshaw wrote: > On Arm the PR107453 change is causing all anonymous arguments to be passed on the > stack, which is incorrect per the ABI. On a target that uses > 'pretend_outgoing_vararg_named', why is it correct to set n_named_args to > zero? Is it enough to guard both the statements you've added with > !targetm.calls.pretend_outgoing_args_named? The TYPE_NO_NAMED_ARGS_STDARG_P functions (C23 fns like void foo (...) {}) have NULL type_arg_types, so the list_length (type_arg_types) isn't done for it, but it should be handled as if it was non-NULL but list length was 0. So, for the if (type_arg_types != 0) n_named_args = (list_length (type_arg_types) /* Count the struct value address, if it is passed as a parm. */ + structure_value_addr_parm); else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype)) n_named_args = 0; else /* If we know nothing, treat all args as named. */ n_named_args = num_actuals; case, I think guarding it by any target hooks is wrong, although I guess it should have been n_named_args = structure_value_addr_parm; instead of n_named_args = 0; For the second if (type_arg_types != 0 && targetm.calls.strict_argument_naming (args_so_far)) ; else if (type_arg_types != 0 && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far)) /* Don't include the last named arg. */ --n_named_args; else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype)) n_named_args = 0; else /* Treat all args as named. */ n_named_args = num_actuals; I think we should treat those as if type_arg_types was non-NULL with 0 elements in the list, except the --n_named_args would for !structure_value_addr_parm lead to n_named_args = -1, I think we want 0 for that case. 2024-03-01 Jakub Jelinek PR middle-end/114136 * calls.cc (expand_call): For TYPE_NO_NAMED_ARGS_STDARG_P set n_named_args initially before INIT_CUMULATIVE_ARGS to structure_value_addr_parm rather than 0, after it don't modify it if strict_argument_naming and clear only if !pretend_outgoing_varargs_named. --- gcc/calls.cc | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/gcc/calls.cc b/gcc/calls.cc index 01f44734743..21d78f9779f 100644 --- a/gcc/calls.cc +++ b/gcc/calls.cc @@ -2938,7 +2938,7 @@ expand_call (tree exp, rtx target, int ignore) /* Count the struct value address, if it is passed as a parm. */ + structure_value_addr_parm); else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype)) - n_named_args = 0; + n_named_args = structure_value_addr_parm; else /* If we know nothing, treat all args as named. */ n_named_args = num_actuals; @@ -2970,14 +2970,15 @@ expand_call (tree exp, rtx target, int ignore) we do not have any reliable way to pass unnamed args in registers, so we must force them into memory. */ - if (type_arg_types != 0 + if ((type_arg_types != 0 || TYPE_NO_NAMED_ARGS_STDARG_P (funtype)) && targetm.calls.strict_argument_naming (args_so_far)) ; else if (type_arg_types != 0 && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far)) /* Don't include the last named arg. */ --n_named_args; - else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype)) + else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype) + && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far)) n_named_args = 0; else /* Treat all args as named. */