[PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek]

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  <jakub@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.

--- 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

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Richard Biener]

On Mon, 9 Jan 2023, Jakub Jelinek 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?

LGTM.

Richard.

> 2023-01-09  Jakub Jelinek  <jakub@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.
> 
> --- 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
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Richard Earnshaw]

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  <jakub@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
> 

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek]

On Tue, Feb 27, 2024 at 04:41:32PM +0000, Richard Earnshaw wrote:
> > 2023-01-09  Jakub Jelinek  <jakub@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?

I'm afraid I haven't heard of that target hook before.
All I was doing with that change was fixing a regression reported in the PR
for ppc64le/sparc/nvptx/loongarch at least.

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;
bet (but no testing done, don't even know which targets return what for
those hooks) we should treat those as if type_arg_types was non-NULL
with 0 elements in the list, except the --n_named_args doesn't make sense
because that would decrease it to -1.
So perhaps
  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)
	   && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far)))
    ;
  else
    /* Treat all args as named.  */
    n_named_args = num_actuals;

(or n_named_args = 0; instead of ; before the final else?  Dunno).
I guess we need some testsuite coverage for caller/callee ABI match of
struct S { char p[64]; };
struct S foo (...);

	Jakub

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Richard Earnshaw]

[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  <jakub@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
>>

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek]

On Tue, Feb 27, 2024 at 06:25:21PM +0100, Jakub Jelinek wrote:
> I guess we need some testsuite coverage for caller/callee ABI match of
> struct S { char p[64]; };
> struct S foo (...);

Maybe the test below?  Passes on x86_64 -m32/-m64, but I guess that doesn't
care at all about the named vs. not named distinction.
The test is a copy of c23-stdarg-4.c, just with all the functions returning
a large struct.

2024-02-27  Jakub Jelinek  <jakub@redhat.com>

	* gcc.dg/c23-stdarg-6.c: New test.

--- gcc/testsuite/gcc.dg/c23-stdarg-6.c.jj	2024-02-27 18:39:04.807821107 +0100
+++ gcc/testsuite/gcc.dg/c23-stdarg-6.c	2024-02-27 18:51:44.706308490 +0100
@@ -0,0 +1,217 @@
+/* Test C23 variadic functions with no named parameters, or last named
+   parameter with a declaration not allowed in C17.  Execution tests.  */
+/* { dg-do run } */
+/* { dg-options "-std=c23 -pedantic-errors" } */
+
+#include <stdarg.h>
+
+extern void abort (void);
+extern void exit (int);
+struct s { char c[1000]; };
+
+struct s
+f (...)
+{
+  va_list ap;
+  va_start (ap);
+  double r = va_arg (ap, int);
+  r += va_arg (ap, double);
+  r += va_arg (ap, int);
+  r += va_arg (ap, double);
+  va_end (ap);
+  struct s ret = {};
+  ret.c[0] = r;
+  ret.c[999] = 42;
+  return ret;
+}
+
+struct s
+g (...)
+{
+  va_list ap;
+  va_start (ap, random ! ignored, ignored ** text);
+  for (int i = 0; i < 10; i++)
+    if (va_arg (ap, double) != i)
+      abort ();
+  va_end (ap);
+  struct s ret = {};
+  ret.c[0] = 17;
+  ret.c[999] = 58;
+  return ret;
+}
+
+struct s
+h1 (register int x, ...)
+{
+  va_list ap;
+  va_start (ap);
+  for (int i = 0; i < 10; i++)
+    {
+      if (va_arg (ap, double) != i)
+	abort ();
+      i++;
+      if (va_arg (ap, int) != i)
+	abort ();
+    }
+  va_end (ap);
+  struct s ret = {};
+  ret.c[0] = 32;
+  ret.c[999] = 95;
+  return ret;
+}
+
+struct s
+h2 (int x(), ...)
+{
+  va_list ap;
+  va_start (ap);
+  for (int i = 0; i < 10; i++)
+    {
+      if (va_arg (ap, double) != i)
+	abort ();
+      i++;
+      if (va_arg (ap, int) != i)
+	abort ();
+    }
+  va_end (ap);
+  struct s ret = {};
+  ret.c[0] = 5;
+  ret.c[999] = 125;
+  return ret;
+}
+
+struct s
+h3 (int x[10], ...)
+{
+  va_list ap;
+  va_start (ap);
+  for (int i = 0; i < 10; i++)
+    {
+      if (va_arg (ap, double) != i)
+	abort ();
+      i++;
+      if (va_arg (ap, int) != i)
+	abort ();
+    }
+  va_end (ap);
+  struct s ret = {};
+  ret.c[0] = 8;
+  ret.c[999] = 12;
+  return ret;
+}
+
+struct s
+h4 (char x, ...)
+{
+  va_list ap;
+  va_start (ap);
+  for (int i = 0; i < 10; i++)
+    {
+      if (va_arg (ap, double) != i)
+	abort ();
+      i++;
+      if (va_arg (ap, int) != i)
+	abort ();
+    }
+  va_end (ap);
+  struct s ret = {};
+  ret.c[0] = 18;
+  ret.c[999] = 28;
+  return ret;
+}
+
+struct s
+h5 (float x, ...)
+{
+  va_list ap;
+  va_start (ap);
+  for (int i = 0; i < 10; i++)
+    {
+      if (va_arg (ap, double) != i)
+	abort ();
+      i++;
+      if (va_arg (ap, int) != i)
+	abort ();
+    }
+  va_end (ap);
+  struct s ret = {};
+  ret.c[0] = 38;
+  ret.c[999] = 48;
+  return ret;
+}
+
+struct s
+h6 (volatile long x, ...)
+{
+  va_list ap;
+  va_start (ap);
+  for (int i = 0; i < 10; i++)
+    {
+      if (va_arg (ap, double) != i)
+	abort ();
+      i++;
+      if (va_arg (ap, int) != i)
+	abort ();
+    }
+  va_end (ap);
+  struct s ret = {};
+  ret.c[0] = 58;
+  ret.c[999] = 68;
+  return ret;
+}
+
+struct s
+h7 (volatile struct s x, ...)
+{
+  va_list ap;
+  va_start (ap);
+  for (int i = 0; i < 10; i++)
+    {
+      if (va_arg (ap, double) != i)
+	abort ();
+      i++;
+      if (va_arg (ap, int) != i)
+	abort ();
+    }
+  va_end (ap);
+  struct s ret = {};
+  ret.c[0] = 78;
+  ret.c[999] = 88;
+  return ret;
+}
+
+int
+main ()
+{
+  struct s x = f (1, 2.0, 3, 4.0);
+  if (x.c[0] != 10 || x.c[999] != 42)
+    abort ();
+  x = g (0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0);
+  if (x.c[0] != 17 || x.c[999] != 58)
+    abort ();
+  x = g (0.0f, 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f);
+  if (x.c[0] != 17 || x.c[999] != 58)
+    abort ();
+  x = h1 (0, 0.0, 1, 2.0, 3, 4.0, 5, 6.0, 7, 8.0, 9);
+  if (x.c[0] != 32 || x.c[999] != 95)
+    abort ();
+  x = h2 (0, 0.0, 1, 2.0, 3, 4.0, 5, 6.0, 7, 8.0, 9);
+  if (x.c[0] != 5 || x.c[999] != 125)
+    abort ();
+  x = h3 (0, 0.0, 1, 2.0, 3, 4.0, 5, 6.0, 7, 8.0, 9);
+  if (x.c[0] != 8 || x.c[999] != 12)
+    abort ();
+  x = h4 (0, 0.0, 1, 2.0, 3, 4.0, 5, 6.0, 7, 8.0, 9);
+  if (x.c[0] != 18 || x.c[999] != 28)
+    abort ();
+  x = h5 (0, 0.0, 1, 2.0, 3, 4.0, 5, 6.0, 7, 8.0, 9);
+  if (x.c[0] != 38 || x.c[999] != 48)
+    abort ();
+  x = h6 (0, 0.0, 1, 2.0, 3, 4.0, 5, 6.0, 7, 8.0, 9);
+  if (x.c[0] != 58 || x.c[999] != 68)
+    abort ();
+  x = h7 ((struct s) {}, 0.0, 1, 2.0, 3, 4.0, 5, 6.0, 7, 8.0, 9);
+  if (x.c[0] != 78 || x.c[999] != 88)
+    abort ();
+  exit (0);
+}


	Jakub

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek]

On Tue, Feb 27, 2024 at 06:54:49PM +0100, Jakub Jelinek wrote:
> On Tue, Feb 27, 2024 at 06:25:21PM +0100, Jakub Jelinek wrote:
> > I guess we need some testsuite coverage for caller/callee ABI match of
> > struct S { char p[64]; };
> > struct S foo (...);
> 
> Maybe the test below?  Passes on x86_64 -m32/-m64, but I guess that doesn't
> care at all about the named vs. not named distinction.
> The test is a copy of c23-stdarg-4.c, just with all the functions returning
> a large struct.
> 
> 2024-02-27  Jakub Jelinek  <jakub@redhat.com>
> 
> 	* gcc.dg/c23-stdarg-6.c: New test.

I've committed the testcase to trunk now as obvious, so that we can see what
targets are broken.

	Jakub

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Richard Earnshaw (lists)]

On 27/02/2024 17:25, Jakub Jelinek wrote:
> On Tue, Feb 27, 2024 at 04:41:32PM +0000, Richard Earnshaw wrote:
>>> 2023-01-09  Jakub Jelinek  <jakub@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?
> 
> I'm afraid I haven't heard of that target hook before.
> All I was doing with that change was fixing a regression reported in the PR
> for ppc64le/sparc/nvptx/loongarch at least.
> 
> 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;
> bet (but no testing done, don't even know which targets return what for
> those hooks) we should treat those as if type_arg_types was non-NULL
> with 0 elements in the list, except the --n_named_args doesn't make sense
> because that would decrease it to -1.
> So perhaps
>   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)
> 	   && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far)))
>     ;
>   else
>     /* Treat all args as named.  */
>     n_named_args = num_actuals;

I tried the above on arm, aarch64 and x86_64 and that seems fine, including the new testcase you added.

R.

> 
> (or n_named_args = 0; instead of ; before the final else?  Dunno).
> I guess we need some testsuite coverage for caller/callee ABI match of
> struct S { char p[64]; };
> struct S foo (...);
> 
> 	Jakub
> 

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Richard Earnshaw]

On 29/02/2024 14:10, Richard Earnshaw (lists) wrote:
> On 27/02/2024 17:25, Jakub Jelinek wrote:
>> On Tue, Feb 27, 2024 at 04:41:32PM +0000, Richard Earnshaw wrote:
>>>> 2023-01-09  Jakub Jelinek  <jakub@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?
>>
>> I'm afraid I haven't heard of that target hook before.
>> All I was doing with that change was fixing a regression reported in the PR
>> for ppc64le/sparc/nvptx/loongarch at least.
>>
>> 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;
>> bet (but no testing done, don't even know which targets return what for
>> those hooks) we should treat those as if type_arg_types was non-NULL
>> with 0 elements in the list, except the --n_named_args doesn't make sense
>> because that would decrease it to -1.
>> So perhaps
>>   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)
>> 	   && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far)))
>>     ;
>>   else
>>     /* Treat all args as named.  */
>>     n_named_args = num_actuals;
> 
> I tried the above on arm, aarch64 and x86_64 and that seems fine, including the new testcase you added.
> 

I should mention though, that INIT_CUMULATIVE_ARGS on arm ignores n_named_args entirely, it doesn't need it (I don't think it even existed when the AAPCS code was added).

R.

> R.
> 
>>
>> (or n_named_args = 0; instead of ; before the final else?  Dunno).
>> I guess we need some testsuite coverage for caller/callee ABI match of
>> struct S { char p[64]; };
>> struct S foo (...);
>>
>> 	Jakub
>>
> 

[PATCH] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek]

On Thu, Feb 29, 2024 at 02:14:05PM +0000, Richard Earnshaw wrote:
> > I tried the above on arm, aarch64 and x86_64 and that seems fine,
> > including the new testcase you added.
> > 
> 
> I should mention though, that INIT_CUMULATIVE_ARGS on arm ignores
> n_named_args entirely, it doesn't need it (I don't think it even existed
> when the AAPCS code was added).

So far I've just checked that the new testcase passes not just on
x86_64/i686-linux, but also on {powerpc64le,s390x,aarch64}-linux
with vanilla trunk.
Haven't posted this patch in patch form, plus while I'm not really sure
whether setting n_named_args to 0 or not changing in the
!pretend_outgoing_varargs_named is right, the setting to 0 feels more
correct to me.  If structure_value_addr_parm is 1, the function effectively
has a single named argument and then ... args and if the target wants
n_named_args to be number of named arguments except the last, then that
should be 0 rather than 1.

Thus, is the following patch ok for trunk then?

2024-02-29  Jakub Jelinek  <jakub@redhat.com>

	PR target/107453
	* 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.jj	2024-01-22 11:48:08.045847508 +0100
+++ gcc/calls.cc	2024-02-29 16:24:47.799855912 +0100
@@ -2938,7 +2938,7 @@ expand_call (tree exp, rtx target, int i
 	 /* 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 i
      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.  */

	Jakub

Re: [PATCH] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Richard Earnshaw (lists)]

On 29/02/2024 15:55, Jakub Jelinek wrote:
> On Thu, Feb 29, 2024 at 02:14:05PM +0000, Richard Earnshaw wrote:
>>> I tried the above on arm, aarch64 and x86_64 and that seems fine,
>>> including the new testcase you added.
>>>
>>
>> I should mention though, that INIT_CUMULATIVE_ARGS on arm ignores
>> n_named_args entirely, it doesn't need it (I don't think it even existed
>> when the AAPCS code was added).
> 
> So far I've just checked that the new testcase passes not just on
> x86_64/i686-linux, but also on {powerpc64le,s390x,aarch64}-linux
> with vanilla trunk.
> Haven't posted this patch in patch form, plus while I'm not really sure
> whether setting n_named_args to 0 or not changing in the
> !pretend_outgoing_varargs_named is right, the setting to 0 feels more
> correct to me.  If structure_value_addr_parm is 1, the function effectively
> has a single named argument and then ... args and if the target wants
> n_named_args to be number of named arguments except the last, then that
> should be 0 rather than 1.
> 
> Thus, is the following patch ok for trunk then?

The comment at the start of the section says

  /* Now possibly adjust the number of named args.
     Normally, don't include the last named arg if anonymous args follow.
     We do include the last named arg if
     targetm.calls.strict_argument_naming() returns nonzero.
     (If no anonymous args follow, the result of list_length is actually
     one too large.  This is harmless.)

So in the case of strict_argument_naming perhaps it should return 1, but 0 for other cases.

R.

> 
> 2024-02-29  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR target/107453
> 	* 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.jj	2024-01-22 11:48:08.045847508 +0100
> +++ gcc/calls.cc	2024-02-29 16:24:47.799855912 +0100
> @@ -2938,7 +2938,7 @@ expand_call (tree exp, rtx target, int i
>  	 /* 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 i
>       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.  */
> 
> 	Jakub
> 

Re: [PATCH] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek]

On Thu, Feb 29, 2024 at 05:23:25PM +0000, Richard Earnshaw (lists) wrote:
> On 29/02/2024 15:55, Jakub Jelinek wrote:
> > On Thu, Feb 29, 2024 at 02:14:05PM +0000, Richard Earnshaw wrote:
> >>> I tried the above on arm, aarch64 and x86_64 and that seems fine,
> >>> including the new testcase you added.
> >>>
> >>
> >> I should mention though, that INIT_CUMULATIVE_ARGS on arm ignores
> >> n_named_args entirely, it doesn't need it (I don't think it even existed
> >> when the AAPCS code was added).
> > 
> > So far I've just checked that the new testcase passes not just on
> > x86_64/i686-linux, but also on {powerpc64le,s390x,aarch64}-linux
> > with vanilla trunk.
> > Haven't posted this patch in patch form, plus while I'm not really sure
> > whether setting n_named_args to 0 or not changing in the
> > !pretend_outgoing_varargs_named is right, the setting to 0 feels more
> > correct to me.  If structure_value_addr_parm is 1, the function effectively
> > has a single named argument and then ... args and if the target wants
> > n_named_args to be number of named arguments except the last, then that
> > should be 0 rather than 1.
> > 
> > Thus, is the following patch ok for trunk then?
> 
> The comment at the start of the section says
> 
>   /* Now possibly adjust the number of named args.
>      Normally, don't include the last named arg if anonymous args follow.
>      We do include the last named arg if
>      targetm.calls.strict_argument_naming() returns nonzero.
>      (If no anonymous args follow, the result of list_length is actually
>      one too large.  This is harmless.)
> 
> So in the case of strict_argument_naming perhaps it should return 1, but 0 for other cases.

The TYPE_NO_NAMED_ARGS_STDARG_P (funtype) case is as if type_arg_types != 0
and list_length (type_arg_types) == 0, i.e. no user named arguments.
As list_length (NULL) returns 0, perhaps it could be even handled just the
by changing all the type_arg_types != 0 checks to
type_arg_types != 0 || TYPE_NO_NAMED_ARGS_STDARG_P (funtype)
There are just 2 cases I'm worried about, one is that I think rest of
calls.cc nor the backends are prepared to see n_named_args -1 after the
adjustments, I think it is better to use 0, and then the question is what
the !strict_argument_naming && !pretend_outgoing_varargs_named case
wants to do for the aggregate return.  The patch as posted for
void foo (...); void bar () { foo (1, 2, 3); }
will set n_named_args initially to 0 (no named args) and with the
adjustments for strict_argument_naming 0, otherwise for !pretend
0 as well, otherwise 3.
For
struct { char buf[4096]; } baz (...); void qux () { baz (1, 2, 3); }
the patch sets n_named_args initially to 1 (the hidden return) and
with the arguments for strict keep it at 1, for !pretend 0 and otherwise
3.

So, which case do you think is handled incorrectly with that?

	Jakub

Re: [PATCH] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Richard Earnshaw (lists)]

On 29/02/2024 17:38, Jakub Jelinek wrote:
> On Thu, Feb 29, 2024 at 05:23:25PM +0000, Richard Earnshaw (lists) wrote:
>> On 29/02/2024 15:55, Jakub Jelinek wrote:
>>> On Thu, Feb 29, 2024 at 02:14:05PM +0000, Richard Earnshaw wrote:
>>>>> I tried the above on arm, aarch64 and x86_64 and that seems fine,
>>>>> including the new testcase you added.
>>>>>
>>>>
>>>> I should mention though, that INIT_CUMULATIVE_ARGS on arm ignores
>>>> n_named_args entirely, it doesn't need it (I don't think it even existed
>>>> when the AAPCS code was added).
>>>
>>> So far I've just checked that the new testcase passes not just on
>>> x86_64/i686-linux, but also on {powerpc64le,s390x,aarch64}-linux
>>> with vanilla trunk.
>>> Haven't posted this patch in patch form, plus while I'm not really sure
>>> whether setting n_named_args to 0 or not changing in the
>>> !pretend_outgoing_varargs_named is right, the setting to 0 feels more
>>> correct to me.  If structure_value_addr_parm is 1, the function effectively
>>> has a single named argument and then ... args and if the target wants
>>> n_named_args to be number of named arguments except the last, then that
>>> should be 0 rather than 1.
>>>
>>> Thus, is the following patch ok for trunk then?
>>
>> The comment at the start of the section says
>>
>>   /* Now possibly adjust the number of named args.
>>      Normally, don't include the last named arg if anonymous args follow.
>>      We do include the last named arg if
>>      targetm.calls.strict_argument_naming() returns nonzero.
>>      (If no anonymous args follow, the result of list_length is actually
>>      one too large.  This is harmless.)
>>
>> So in the case of strict_argument_naming perhaps it should return 1, but 0 for other cases.
> 
> The TYPE_NO_NAMED_ARGS_STDARG_P (funtype) case is as if type_arg_types != 0
> and list_length (type_arg_types) == 0, i.e. no user named arguments.
> As list_length (NULL) returns 0, perhaps it could be even handled just the
> by changing all the type_arg_types != 0 checks to
> type_arg_types != 0 || TYPE_NO_NAMED_ARGS_STDARG_P (funtype)
> There are just 2 cases I'm worried about, one is that I think rest of
> calls.cc nor the backends are prepared to see n_named_args -1 after the
> adjustments, I think it is better to use 0, and then the question is what
> the !strict_argument_naming && !pretend_outgoing_varargs_named case
> wants to do for the aggregate return.  The patch as posted for
> void foo (...); void bar () { foo (1, 2, 3); }
> will set n_named_args initially to 0 (no named args) and with the
> adjustments for strict_argument_naming 0, otherwise for !pretend
> 0 as well, otherwise 3.
> For
> struct { char buf[4096]; } baz (...); void qux () { baz (1, 2, 3); }
> the patch sets n_named_args initially to 1 (the hidden return) and
> with the arguments for strict keep it at 1, for !pretend 0 and otherwise
> 3.
> 
> So, which case do you think is handled incorrectly with that?

The way I was thinking about it (and testing it on Arm) was to look at n_named_args for the cases of a traditional varargs case, then reduce that by one (except it can't ever be negative).

So for 

void f(...);
void g(int, ...);
struct S { int a[32]; };

struct S h (...);
struct S i (int, ...);

void a ()
{
  struct S x;
  f(1, 2, 3, 4);
  g(1, 2, 3, 4);
  x = h (1, 2, 3, 4);
  x = i (1, 2, 3, 4);
}

There are various permutations that could lead to answers of 0, 1, 2, 4 and 5 depending on how those various targets treat each case and how the result pointer address is handled.  My suspicion is that for a target that has strict argument naming and the result pointer passed as a first argument, the answer for the 'h()' call should be 1, not zero.  

Oh, but wait!  Perhaps that now falls into the initial 'if' clause and we never reach the point where you pick zero.  So perhaps I'm worrying about nothing.

R.

> 
> 	Jakub
> 

Re: [PATCH] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek]

On Thu, Feb 29, 2024 at 05:51:03PM +0000, Richard Earnshaw (lists) wrote:
> Oh, but wait!  Perhaps that now falls into the initial 'if' clause and we never reach the point where you pick zero.  So perhaps I'm worrying about nothing.

If you are worried about the
+  else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype)
+          && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far))
     n_named_args = 0;
case in the patch, we know at that point that the initial n_named_args is
equal to structure_value_addr_parm, so either 0, in that case
    --n_named_args;
would yield the undesirable negative value, so we want 0 instead; for that
case we could as well just have ; in there instead of n_named_args = 0;,
or it is 1, in that case --n_named_args; would turn that into 0.

	Jakub

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Alexandre Oliva]

On Feb 27, 2024, Richard Earnshaw <Richard.Earnshaw@arm.com> wrote:

> 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...

*nod* xref https://gcc.gnu.org/pipermail/gcc-patches/2024-March/646926.html
The patch I proposed was indeed far too limited in scope.

> 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?

ISTM that the change you suggest over Jakub's patch would address the
inconsistency on ARM.

Matthew suggested a patch along these lines in the other thread, that I
xrefed above, that seems sound to me, but I also suspect it won't fix
the ppc64le issue.  My hunch is that we'll need a combination of both,
possibly with further tweaks to adjust for Jakub's just-added test.

-- 
Alexandre Oliva, happy hacker                    https://FSFLA.org/blogs/lxo/
   Free Software Activist                           GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice but
very few check the facts.  Think Assange & Stallman.  The empires strike back

Re: [PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek]

On Fri, Mar 01, 2024 at 01:53:54AM -0300, Alexandre Oliva wrote:
> On Feb 27, 2024, Richard Earnshaw <Richard.Earnshaw@arm.com> wrote:
> 
> > 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...
> 
> *nod* xref https://gcc.gnu.org/pipermail/gcc-patches/2024-March/646926.html
> The patch I proposed was indeed far too limited in scope.
> 
> > 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?
> 
> ISTM that the change you suggest over Jakub's patch would address the
> inconsistency on ARM.

At least in my understanding, the only part of my patch that was being
discussed was the !strict_argument_naming && !pretend_outgoing_args_named
case with structure_value_addr_parm, I don't see how that would affect
ARM, given that it is a !strict_argument_naming && pretend_outgoing_args_named
target.  In that case with the patch as posted n_named_args will be
structure_value_addr_parm before INIT_CUMULATIVE_ARGS and num_actuals
afterwards, I don't see any disagreement on that.

	Jakub

Re: [PATCH] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Richard Earnshaw (lists)]

On 29/02/2024 17:56, Jakub Jelinek wrote:
> On Thu, Feb 29, 2024 at 05:51:03PM +0000, Richard Earnshaw (lists) wrote:
>> Oh, but wait!  Perhaps that now falls into the initial 'if' clause and we never reach the point where you pick zero.  So perhaps I'm worrying about nothing.
> 
> If you are worried about the
> +  else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype)
> +          && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far))
>      n_named_args = 0;
> case in the patch, we know at that point that the initial n_named_args is
> equal to structure_value_addr_parm, so either 0, in that case
>     --n_named_args;
> would yield the undesirable negative value, so we want 0 instead; for that
> case we could as well just have ; in there instead of n_named_args = 0;,
> or it is 1, in that case --n_named_args; would turn that into 0.
> 
> 	Jakub
> 

No, I was thinking about the case of strict_argument_naming when the first argument is the artificial return value pointer.  In that case we'd want n_named_args=1.

But I think it's a non-issue as that will be caught by 

  if ((type_arg_types != 0 || TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
       && targetm.calls.strict_argument_naming (args_so_far))
     ;

R.

Re: [PATCH] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek]

On Fri, Mar 01, 2024 at 01:53:08PM +0000, Richard Earnshaw (lists) wrote:
> On 29/02/2024 17:56, Jakub Jelinek wrote:
> > On Thu, Feb 29, 2024 at 05:51:03PM +0000, Richard Earnshaw (lists) wrote:
> >> Oh, but wait!  Perhaps that now falls into the initial 'if' clause and we never reach the point where you pick zero.  So perhaps I'm worrying about nothing.
> > 
> > If you are worried about the
> > +  else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype)
> > +          && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far))
> >      n_named_args = 0;
> > case in the patch, we know at that point that the initial n_named_args is
> > equal to structure_value_addr_parm, so either 0, in that case
> >     --n_named_args;
> > would yield the undesirable negative value, so we want 0 instead; for that
> > case we could as well just have ; in there instead of n_named_args = 0;,
> > or it is 1, in that case --n_named_args; would turn that into 0.
> > 
> > 	Jakub
> > 
> 
> No, I was thinking about the case of strict_argument_naming when the first argument is the artificial return value pointer.  In that case we'd want n_named_args=1.
> 
> But I think it's a non-issue as that will be caught by 
> 
>   if ((type_arg_types != 0 || TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
>        && targetm.calls.strict_argument_naming (args_so_far))
>      ;

Yes, that for strict argument naming and calls to
struct large_struct foo (...);
with the patch we set n_named_args = 1 early:
  else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
    n_named_args = structure_value_addr_parm;
and then
  if ((type_arg_types != 0 || TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
       && targetm.calls.strict_argument_naming (args_so_far))
    ;
doesn't change it.

	Jakub

Re: [PATCH] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Richard Earnshaw (lists)]

On 29/02/2024 15:55, Jakub Jelinek wrote:
> On Thu, Feb 29, 2024 at 02:14:05PM +0000, Richard Earnshaw wrote:
>>> I tried the above on arm, aarch64 and x86_64 and that seems fine,
>>> including the new testcase you added.
>>>
>>
>> I should mention though, that INIT_CUMULATIVE_ARGS on arm ignores
>> n_named_args entirely, it doesn't need it (I don't think it even existed
>> when the AAPCS code was added).
> 
> So far I've just checked that the new testcase passes not just on
> x86_64/i686-linux, but also on {powerpc64le,s390x,aarch64}-linux
> with vanilla trunk.
> Haven't posted this patch in patch form, plus while I'm not really sure
> whether setting n_named_args to 0 or not changing in the
> !pretend_outgoing_varargs_named is right, the setting to 0 feels more
> correct to me.  If structure_value_addr_parm is 1, the function effectively
> has a single named argument and then ... args and if the target wants
> n_named_args to be number of named arguments except the last, then that
> should be 0 rather than 1.
> 
> Thus, is the following patch ok for trunk then?
> 
> 2024-02-29  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR target/107453

PR 114136

Would be more appropriate for this, I think.

Otherwise, OK.

R.

> 	* 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.jj	2024-01-22 11:48:08.045847508 +0100
> +++ gcc/calls.cc	2024-02-29 16:24:47.799855912 +0100
> @@ -2938,7 +2938,7 @@ expand_call (tree exp, rtx target, int i
>  	 /* 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 i
>       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.  */
> 
> 	Jakub
>