[resending, apologies, I accidentally CC'd the wrong person last time]
On 27/02/2024 16:41, Richard Earnshaw wrote: > > > On 09/01/2023 10:32, Jakub Jelinek via Gcc-patches wrote: >> Hi! >> >> On powerpc64le-linux, the following patch fixes >> -FAIL: gcc.dg/c2x-stdarg-4.c execution test >> -FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c -O0 execution test >> -FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c -O1 execution test >> -FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c -O2 execution test >> -FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c -O2 -flto >> -fno-use-linker-plugin -flto-partition=none execution test >> -FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c -O2 -flto -fuse-linker-plugin >> -fno-fat-lto-objects execution test >> -FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c -O3 -g execution test >> -FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c -Os execution test >> The problem is mismatch between the caller and callee side. >> On the callee side, we do: >> /* NAMED_ARG is a misnomer. We really mean 'non-variadic'. */ >> if (!cfun->stdarg) >> data->arg.named = 1; /* No variadic parms. */ >> else if (DECL_CHAIN (parm)) >> data->arg.named = 1; /* Not the last non-variadic parm. */ >> else if (targetm.calls.strict_argument_naming (all->args_so_far)) >> data->arg.named = 1; /* Only variadic ones are unnamed. */ >> else >> data->arg.named = 0; /* Treat as variadic. */ >> which is later passed to the target hooks to determine if a particular >> argument is named or not. Now, cfun->stdarg is determined from the stdarg_p >> call, which for the new C2X TYPE_NO_NAMED_ARGS_STDARG_P function types >> (rettype fn (...)) returns true. Such functions have no named arguments, >> so data->arg.named will be 0 in function.cc. But on the caller side, >> as TYPE_NO_NAMED_ARGS_STDARG_P function types have TYPE_ARG_TYPES NULL, >> we instead treat those calls as unprototyped even when they are prototyped >> - /* If we know nothing, treat all args as named. */ n_named_args = >> num_actuals; >> in 2 spots. We need to treat the TYPE_NO_NAMED_ARGS_STDARG_P cases as >> prototyped with no named arguments. >> >> Bootstrapped/regtested on x86_64-linux, i686-linux, powerpc64le-linux (where >> it fixes the above failures), aarch64-linux and s390x-linux, ok for trunk? >> >> 2023-01-09 Jakub Jelinek <ja...@redhat.com> >> >> PR target/107453 >> * calls.cc (expand_call): For calls with >> TYPE_NO_NAMED_ARGS_STDARG_P (funtype) use zero for n_named_args. >> Formatting fix. > > This one has been festering for a while; both Alexandre and Torbjorn have > attempted to fix it recently, but I'm not sure either is really right... > > On Arm this 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? > > R. > >> >> --- gcc/calls.cc.jj 2023-01-02 09:32:28.834192105 +0100 >> +++ gcc/calls.cc 2023-01-06 14:52:14.740594896 +0100 >> @@ -2908,8 +2908,8 @@ expand_call (tree exp, rtx target, int i >> } >> >> /* Count the arguments and set NUM_ACTUALS. */ >> - num_actuals = >> - call_expr_nargs (exp) + num_complex_actuals + structure_value_addr_parm; >> + num_actuals >> + = call_expr_nargs (exp) + num_complex_actuals + >> structure_value_addr_parm; >> >> /* Compute number of named args. >> First, do a raw count of the args for INIT_CUMULATIVE_ARGS. */ >> @@ -2919,6 +2919,8 @@ expand_call (tree exp, rtx target, int i >> = (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; >> @@ -2957,6 +2959,8 @@ expand_call (tree exp, rtx target, int i >> && ! 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; >> >> Jakub >>
