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* s390-tdep.c: Tweak argument-passing to match GCC bugs.

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(is_float_singleton, is_struct_like, is_float_like): New
functions, that isolate the weirdness.
(is_double_or_float, is_simple_arg, pass_by_copy_ref,
is_double_arg): Use is_struct_like and is_float_like, rather than
testing the type codes ourselves.
(s390_push_arguments): When passing args on the stack, align each
on to a four-byte boundary, regardless of what the type itself
needs.
This commit is contained in:
Jim Blandy 2001-11-16 21:40:36 +00:00
parent e5d6381133
commit 20a940cc8c
2 changed files with 85 additions and 14 deletions
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12
gdb/ChangeLog
View File

@ -1,3 +1,15 @@
2001-11-16 Jim Blandy <jimb@redhat.com>
* s390-tdep.c: Tweak argument-passing to match GCC bugs.
(is_float_singleton, is_struct_like, is_float_like): New
functions, that isolate the weirdness.
(is_double_or_float, is_simple_arg, pass_by_copy_ref,
is_double_arg): Use is_struct_like and is_float_like, rather than
testing the type codes ourselves.
(s390_push_arguments): When passing args on the stack, align each
on to a four-byte boundary, regardless of what the type itself
needs.
2001-11-16 Ben Harris <bjh21@netbsd.org>
* Makefile.in (os9kread.o): Replace $< with autoconf-approved

87
gdb/s390-tdep.c
View File

@ -1221,6 +1221,68 @@ is_pointer_like (struct type *type)
}
/* Return non-zero if TYPE is a `float singleton' or `double
singleton', zero otherwise.
A `T singleton' is a struct type with one member, whose type is
either T or a `T singleton'. So, the following are all float
singletons:
struct { float x };
struct { struct { float x; } x; };
struct { struct { struct { float x; } x; } x; };
... and so on.
WHY THE HECK DO WE CARE ABOUT THIS??? Well, it turns out that GCC
passes all float singletons and double singletons as if they were
simply floats or doubles. This is *not* what the ABI says it
should do. */
static int
is_float_singleton (struct type *type)
{
return (TYPE_CODE (type) == TYPE_CODE_STRUCT
&& TYPE_NFIELDS (type) == 1
&& (TYPE_CODE (TYPE_FIELD_TYPE (type, 0)) == TYPE_CODE_FLT
|| is_float_singleton (TYPE_FIELD_TYPE (type, 0))));
}
/* Return non-zero if TYPE is a struct-like type, zero otherwise.
"Struct-like" types are those that should be passed as structs are:
structs and unions.
As an odd quirk, not mentioned in the ABI, GCC passes float and
double singletons as if they were a plain float, double, etc. (The
corresponding union types are handled normally.) So we exclude
those types here. *shrug* */
static int
is_struct_like (struct type *type)
{
enum type_code code = TYPE_CODE (type);
return (code == TYPE_CODE_UNION
|| (code == TYPE_CODE_STRUCT && ! is_float_singleton (type)));
}
/* Return non-zero if TYPE is a float-like type, zero otherwise.
"Float-like" types are those that should be passed as
floating-point values are.
You'd think this would just be floats, doubles, long doubles, etc.
But as an odd quirk, not mentioned in the ABI, GCC passes float and
double singletons as if they were a plain float, double, etc. (The
corresponding union types are handled normally.) So we exclude
those types here. *shrug* */
static int
is_float_like (struct type *type)
{
return (TYPE_CODE (type) == TYPE_CODE_FLT
|| is_float_singleton (type));
}
/* Return non-zero if TYPE is considered a `DOUBLE_OR_FLOAT', as
defined by the parameter passing conventions described in the
"Linux for S/390 ELF Application Binary Interface Supplement".
@ -1228,7 +1290,7 @@ is_pointer_like (struct type *type)
static int
is_double_or_float (struct type *type)
{
return (TYPE_CODE (type) == TYPE_CODE_FLT
return (is_float_like (type)
&& (TYPE_LENGTH (type) == 4
|| TYPE_LENGTH (type) == 8));
}
@ -1240,17 +1302,14 @@ is_double_or_float (struct type *type)
static int
is_simple_arg (struct type *type)
{
enum type_code code = TYPE_CODE (type);
unsigned length = TYPE_LENGTH (type);
/* This is almost a direct translation of the ABI's language, except
that we have to exclude 8-byte structs; those are DOUBLE_ARGs. */
return ((is_integer_like (type) && length <= 4)
|| is_pointer_like (type)
|| ((code == TYPE_CODE_STRUCT
|| code == TYPE_CODE_UNION)
&& length != 8)
|| (code == TYPE_CODE_FLT && length == 16));
|| (is_struct_like (type) && length != 8)
|| (is_float_like (type) && length == 16));
}
@ -1260,12 +1319,10 @@ is_simple_arg (struct type *type)
static int
pass_by_copy_ref (struct type *type)
{
enum type_code code = TYPE_CODE (type);
unsigned length = TYPE_LENGTH (type);
return (((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION)
&& length != 1 && length != 2 && length != 4)
|| (code == TYPE_CODE_FLT && length == 16));
return ((is_struct_like (type) && length != 1 && length != 2 && length != 4)
|| (is_float_like (type) && length == 16));
}
@ -1294,12 +1351,10 @@ extend_simple_arg (struct value *arg)
static int
is_double_arg (struct type *type)
{
enum type_code code = TYPE_CODE (type);
unsigned length = TYPE_LENGTH (type);
return ((is_integer_like (type)
|| code == TYPE_CODE_STRUCT
|| code == TYPE_CODE_UNION)
|| is_struct_like (type))
&& length == 8);
}
@ -1512,7 +1567,11 @@ s390_push_arguments (int nargs, struct value **args, CORE_ADDR sp,
}
else
{
starg = round_up (starg, alignment_of (type));
/* You'd think we should say:
starg = round_up (starg, alignment_of (type));
Unfortunately, GCC seems to simply align the stack on
a four-byte boundary, even when passing doubles. */
starg = round_up (starg, 4);
write_memory (starg, VALUE_CONTENTS (arg), length);
starg += length;
}