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Re: revised varargs patch with references
> Date: Wed, 29 Mar 2000 01:11:31 -0800
> From: Richard Henderson <rth@cygnus.com>
> Cc: gcc-patches@gcc.gnu.org
>
> On Tue, Mar 28, 2000 at 11:59:26AM -0800, Geoff Keating wrote:
> > This patch uses references to make it clear when the va_start and
> > va_copy macros change their first argument. It works surprisingly
> > well, even in C (once you explain to convert_for_assignment what
> > references are).
>
> Yes, this is much cleaner.
>
> > Tested with no varargs failures on x86 linux...
>
> Except that it crashes quite hard on alpha, right in
> the middle of the reference widgetry you added. :-(
Ah. I'd used comp_target_types where I should have used comptypes.
Here's a revised patch. Bootstraps & tests OK on x86 and alpha, and
tests OK on ppc.
OK to commit?
--
- Geoffrey Keating <geoffk@cygnus.com>
===File ~/patches/cygnus/egcs-vastart-fix-4.patch===========
2000-03-29 Geoff Keating <geoffk@cygnus.com>
* c-common.c (c_common_nodes_and_builtins): The first parameter to
__builtin_va_start and __builtin_va_copy is now either a 'va_list'
or a reference to a va_list.
* builtins.c (stabilize_va_list): Simplify now we don't have to
work around C array address decay.
* c-typeck.c (convert_for_assignment): Handle assignment to
a reference parameter by taking the address of the RHS.
* ginclude/stdarg.h (va_start): Don't take address of first parameter.
(va_copy): Likewise.
(__va_copy): Likewise.
* ginclude/varargs.h (va_start): Likewise.
(__va_copy): Likewise.
Index: builtins.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/builtins.c,v
retrieving revision 1.41
diff -c -p -r1.41 builtins.c
*** builtins.c 2000/03/24 23:47:17 1.41
--- builtins.c 2000/03/29 15:33:50
*************** expand_builtin_next_arg (arglist)
*** 1901,1966 ****
from multiple evaluations. */
static tree
! stabilize_va_list (valist, was_ptr)
tree valist;
! int was_ptr;
{
if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
{
! /* If stdarg.h took the address of an array-type valist that was passed
! as a parameter, we'll have taken the address of the parameter itself
! rather than the array as we'd intended. Undo this mistake. */
!
! if (was_ptr)
! {
! STRIP_NOPS (valist);
!
! /* Two cases: either &array, which decomposed to
! <ptr <array <record> valist>>
! or &ptr, which turned into
! <ptr <ptr <record>>>
! In the first case we'll need to put the ADDR_EXPR back
! after frobbing the types as if &array[0]. */
!
! if (TREE_CODE (valist) != ADDR_EXPR)
! abort ();
! valist = TREE_OPERAND (valist, 0);
! }
! if (TYPE_MAIN_VARIANT (TREE_TYPE (valist))
! == TYPE_MAIN_VARIANT (va_list_type_node))
! {
! tree pt = build_pointer_type (TREE_TYPE (va_list_type_node));
! valist = build1 (ADDR_EXPR, pt, valist);
! TREE_SIDE_EFFECTS (valist)
! = TREE_SIDE_EFFECTS (TREE_OPERAND (valist, 0));
! }
! else
{
! if (! POINTER_TYPE_P (TREE_TYPE (valist))
! || (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (valist)))
! != TYPE_MAIN_VARIANT (TREE_TYPE (va_list_type_node))))
! abort ();
}
-
- if (TREE_SIDE_EFFECTS (valist))
- valist = save_expr (valist);
}
else
{
! if (! was_ptr)
! {
! tree pt;
if (! TREE_SIDE_EFFECTS (valist))
return valist;
!
pt = build_pointer_type (va_list_type_node);
! valist = fold (build1 (ADDR_EXPR, pt, valist));
TREE_SIDE_EFFECTS (valist) = 1;
}
if (TREE_SIDE_EFFECTS (valist))
! valist = save_expr (valist);
valist = fold (build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (valist)),
valist));
}
--- 1901,1943 ----
from multiple evaluations. */
static tree
! stabilize_va_list (valist, needs_lvalue)
tree valist;
! int needs_lvalue;
{
if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
{
! if (TREE_SIDE_EFFECTS (valist))
! valist = save_expr (valist);
! /* For this case, the backends will be expecting a pointer to
! TREE_TYPE (va_list_type_node), but it's possible we've
! actually been given an array (an actual va_list_type_node).
! So fix it. */
! if (TREE_CODE (TREE_TYPE (valist)) == ARRAY_TYPE)
{
! tree p1 = build_pointer_type (TREE_TYPE (va_list_type_node));
! tree p2 = build_pointer_type (va_list_type_node);
! valist = build1 (ADDR_EXPR, p2, valist);
! valist = fold (build1 (NOP_EXPR, p1, valist));
}
}
else
{
! tree pt;
+ if (! needs_lvalue)
+ {
if (! TREE_SIDE_EFFECTS (valist))
return valist;
!
pt = build_pointer_type (va_list_type_node);
! valist = fold (build1 (ADDR_EXPR, pt, valist));
TREE_SIDE_EFFECTS (valist) = 1;
}
+
if (TREE_SIDE_EFFECTS (valist))
! valist = save_expr (valist);
valist = fold (build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (valist)),
valist));
}
Index: c-common.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/c-common.c,v
retrieving revision 1.102
diff -c -p -r1.102 c-common.c
*** c-common.c 2000/03/24 20:20:56 1.102
--- c-common.c 2000/03/29 15:33:51
*************** c_common_nodes_and_builtins (cplus_mode,
*** 3478,3484 ****
tree traditional_cptr_type_node;
tree traditional_len_type_node;
tree traditional_len_endlink;
! tree va_list_ptr_type_node;
tree va_list_arg_type_node;
pushdecl (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
--- 3478,3484 ----
tree traditional_cptr_type_node;
tree traditional_len_type_node;
tree traditional_len_endlink;
! tree va_list_ref_type_node;
tree va_list_arg_type_node;
pushdecl (build_decl (TYPE_DECL, get_identifier ("__builtin_va_list"),
*************** c_common_nodes_and_builtins (cplus_mode,
*** 3490,3502 ****
pushdecl (build_decl (TYPE_DECL, get_identifier ("__builtin_size_t"),
sizetype));
- va_list_ptr_type_node = build_pointer_type (va_list_type_node);
-
if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
! va_list_arg_type_node = build_pointer_type (TREE_TYPE (va_list_type_node));
else
! va_list_arg_type_node = va_list_type_node;
!
endlink = void_list_node;
int_endlink = tree_cons (NULL_TREE, integer_type_node, endlink);
double_endlink = tree_cons (NULL_TREE, double_type_node, endlink);
--- 3490,3506 ----
pushdecl (build_decl (TYPE_DECL, get_identifier ("__builtin_size_t"),
sizetype));
if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
! {
! va_list_arg_type_node = va_list_ref_type_node =
! build_pointer_type (TREE_TYPE (va_list_type_node));
! }
else
! {
! va_list_arg_type_node = va_list_type_node;
! va_list_ref_type_node = build_reference_type (va_list_type_node);
! }
!
endlink = void_list_node;
int_endlink = tree_cons (NULL_TREE, integer_type_node, endlink);
double_endlink = tree_cons (NULL_TREE, double_type_node, endlink);
*************** c_common_nodes_and_builtins (cplus_mode,
*** 3725,3752 ****
builtin_function ("__builtin_varargs_start",
build_function_type (void_type_node,
tree_cons (NULL_TREE,
! va_list_ptr_type_node,
endlink)),
BUILT_IN_VARARGS_START, BUILT_IN_NORMAL, NULL_PTR);
builtin_function ("__builtin_stdarg_start",
build_function_type (void_type_node,
tree_cons (NULL_TREE,
! va_list_ptr_type_node,
NULL_TREE)),
BUILT_IN_STDARG_START, BUILT_IN_NORMAL, NULL_PTR);
builtin_function ("__builtin_va_end",
build_function_type (void_type_node,
tree_cons (NULL_TREE,
! va_list_arg_type_node,
endlink)),
BUILT_IN_VA_END, BUILT_IN_NORMAL, NULL_PTR);
builtin_function ("__builtin_va_copy",
build_function_type (void_type_node,
tree_cons (NULL_TREE,
! va_list_ptr_type_node,
tree_cons (NULL_TREE,
va_list_arg_type_node,
endlink))),
--- 3729,3756 ----
builtin_function ("__builtin_varargs_start",
build_function_type (void_type_node,
tree_cons (NULL_TREE,
! va_list_ref_type_node,
endlink)),
BUILT_IN_VARARGS_START, BUILT_IN_NORMAL, NULL_PTR);
builtin_function ("__builtin_stdarg_start",
build_function_type (void_type_node,
tree_cons (NULL_TREE,
! va_list_ref_type_node,
NULL_TREE)),
BUILT_IN_STDARG_START, BUILT_IN_NORMAL, NULL_PTR);
builtin_function ("__builtin_va_end",
build_function_type (void_type_node,
tree_cons (NULL_TREE,
! va_list_ref_type_node,
endlink)),
BUILT_IN_VA_END, BUILT_IN_NORMAL, NULL_PTR);
builtin_function ("__builtin_va_copy",
build_function_type (void_type_node,
tree_cons (NULL_TREE,
! va_list_ref_type_node,
tree_cons (NULL_TREE,
va_list_arg_type_node,
endlink))),
Index: c-typeck.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/c-typeck.c,v
retrieving revision 1.60
diff -c -p -r1.60 c-typeck.c
*** c-typeck.c 2000/03/25 18:34:00 1.60
--- c-typeck.c 2000/03/29 15:33:51
*************** convert_for_assignment (type, rhs, errty
*** 3960,3970 ****
error ("void value not ignored as it ought to be");
return error_mark_node;
}
/* Arithmetic types all interconvert, and enum is treated like int. */
! if ((codel == INTEGER_TYPE || codel == REAL_TYPE || codel == ENUMERAL_TYPE
! || codel == COMPLEX_TYPE)
! && (coder == INTEGER_TYPE || coder == REAL_TYPE || coder == ENUMERAL_TYPE
! || coder == COMPLEX_TYPE))
return convert_and_check (type, rhs);
/* Conversion to a transparent union from its member types.
--- 3960,3991 ----
error ("void value not ignored as it ought to be");
return error_mark_node;
}
+ /* A type converts to a reference to it.
+ This code doesn't fully support references, it's just for the
+ special case of va_start and va_copy. */
+ if (codel == REFERENCE_TYPE
+ && comptypes (TREE_TYPE (type), TREE_TYPE (rhs)) == 1)
+ {
+ if (mark_addressable (rhs) == 0)
+ return error_mark_node;
+ rhs = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (rhs)), rhs);
+
+ /* We already know that these two types are compatible, but they
+ may not be exactly identical. In fact, `TREE_TYPE (type)' is
+ likely to be __builtin_va_list and `TREE_TYPE (rhs)' is
+ likely to be va_list, a typedef to __builtin_va_list, which
+ is different enough that it will cause problems later. */
+ if (TREE_TYPE (TREE_TYPE (rhs)) != TREE_TYPE (type))
+ rhs = build1 (NOP_EXPR, build_pointer_type (TREE_TYPE (type)), rhs);
+
+ rhs = build1 (NOP_EXPR, type, rhs);
+ return rhs;
+ }
/* Arithmetic types all interconvert, and enum is treated like int. */
! else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
! || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE)
! && (coder == INTEGER_TYPE || coder == REAL_TYPE
! || coder == ENUMERAL_TYPE || coder == COMPLEX_TYPE))
return convert_and_check (type, rhs);
/* Conversion to a transparent union from its member types.
Index: ginclude/stdarg.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/ginclude/stdarg.h,v
retrieving revision 1.14
diff -c -p -r1.14 stdarg.h
*** stdarg.h 2000/01/13 00:37:06 1.14
--- stdarg.h 2000/03/29 15:33:51
***************
*** 1,4 ****
! /* Copyright (C) 1989, 1997, 1998, 1999 Free Software Foundation, Inc.
This file is part of GNU CC.
--- 1,4 ----
! /* Copyright (C) 1989, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
This file is part of GNU CC.
*************** typedef __builtin_va_list __gnuc_va_list
*** 51,63 ****
actual type **after default promotions**.
Thus, va_arg (..., short) is not valid. */
! #define va_start(v,l) __builtin_stdarg_start(&(v),l)
#define va_end __builtin_va_end
#define va_arg __builtin_va_arg
#if !defined(__STRICT_ANSI__) || __STDC_VERSION__ + 0 >= 199900L
! #define va_copy(d,s) __builtin_va_copy(&(d),(s))
#endif
! #define __va_copy(d,s) __builtin_va_copy(&(d),(s))
/* Define va_list, if desired, from __gnuc_va_list. */
--- 51,63 ----
actual type **after default promotions**.
Thus, va_arg (..., short) is not valid. */
! #define va_start(v,l) __builtin_stdarg_start((v),l)
#define va_end __builtin_va_end
#define va_arg __builtin_va_arg
#if !defined(__STRICT_ANSI__) || __STDC_VERSION__ + 0 >= 199900L
! #define va_copy(d,s) __builtin_va_copy((d),(s))
#endif
! #define __va_copy(d,s) __builtin_va_copy((d),(s))
/* Define va_list, if desired, from __gnuc_va_list. */
Index: ginclude/varargs.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/ginclude/varargs.h,v
retrieving revision 1.14
diff -c -p -r1.14 varargs.h
*** varargs.h 2000/01/13 00:37:06 1.14
--- varargs.h 2000/03/29 15:33:51
***************
*** 1,4 ****
! /* Copyright (C) 1989, 1997, 1998, 1999 Free Software Foundation, Inc.
This file is part of GNU CC.
--- 1,4 ----
! /* Copyright (C) 1989, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
This file is part of GNU CC.
*************** typedef int __builtin_va_alist_t __attri
*** 63,72 ****
typedef __builtin_va_list __gnuc_va_list;
#endif
! #define va_start(v) __builtin_varargs_start(&(v))
#define va_end __builtin_va_end
#define va_arg __builtin_va_arg
! #define __va_copy(d,s) __builtin_va_copy(&(d),(s))
/* Define va_list from __gnuc_va_list. */
--- 63,72 ----
typedef __builtin_va_list __gnuc_va_list;
#endif
! #define va_start(v) __builtin_varargs_start((v))
#define va_end __builtin_va_end
#define va_arg __builtin_va_arg
! #define __va_copy(d,s) __builtin_va_copy((d),(s))
/* Define va_list from __gnuc_va_list. */
============================================================