* [PATCH v2] gdb: LoongArch: Handle special struct in dummy call
@ 2023-10-08 7:32 Hui Li
2023-10-11 1:13 ` Tiezhu Yang
0 siblings, 1 reply; 2+ messages in thread
From: Hui Li @ 2023-10-08 7:32 UTC (permalink / raw)
To: gdb-patches
When execute the following command on LoongArch:
make check-gdb TESTS="gdb.base/infcall-nested-structs-c++.exp"
there exist some failed testcases:
=== gdb Summary ===
# of expected passes 5533
# of unexpected failures 367
The root cause is related with a struct containing floating-point
members as function argument or return value for a dummy call.
(1) Structure consists of one floating-point member within FRLEN bits
wide, it is passed in an FAR if available.
(2) Structure consists of two floating-point members both within FRLEN
bits wide, it is passed in two FARs if available.
(3) Structure consists of one integer member within GRLEN bits wide and
one floating-point member within FRLEN bits wide, it is passed in a
GAR and an FAR if available.
Note that in the above cases, empty structure or union members are also
ignored even in C++.
Here is a simple test on LoongArch:
loongson@bogon:~$ cat test.c
#include<stdio.h>
struct test {
long a;
double b __attribute__((aligned(16)));
};
struct test val = { 88, 99.99 };
int check_arg_struct (struct test arg)
{
printf("arg.a = %ld\n", arg.a);
printf("arg.b = %f\n", arg.b);
printf("sizeof(val) = %d\n", sizeof(val));
return 1;
}
int main()
{
check_arg_struct (val);
return 0;
}
loongson@bogon:~$ gcc -g test.c -o test
loongson@bogon:~$ ./test
arg.a = 88
arg.b = 99.990000
sizeof(val) = 32
Before:
loongson@bogon:~$ gdb test
...
(gdb) start
...
Temporary breakpoint 1, main () at test.c:19
19 check_arg_struct (val);
(gdb) p check_arg_struct (val)
arg.a = 140737488286128
arg.b = -nan
sizeof(val) = 32
$1 = 1
...
After:
loongson@bogon:~$ gdb test
...
(gdb) start
...
Temporary breakpoint 1, main () at test.c:19
19 check_arg_struct (val);
(gdb) p check_arg_struct (val)
arg.a = 88
arg.b = 99.990000
sizeof(val) = 32
$1 = 1
...
With this patch, there are no failed testcases:
make check-gdb TESTS="gdb.base/infcall-nested-structs-c++.exp"
=== gdb Summary ===
# of expected passes 5900
Signed-off-by: Hui Li <lihui@loongson.cn>
---
gdb/loongarch-tdep.c | 205 +++++++++++++++++++++++++++++++++++++++----
1 file changed, 189 insertions(+), 16 deletions(-)
diff --git a/gdb/loongarch-tdep.c b/gdb/loongarch-tdep.c
index 62c6f9b220e..c65e2414bf8 100644
--- a/gdb/loongarch-tdep.c
+++ b/gdb/loongarch-tdep.c
@@ -516,7 +516,8 @@ static void
compute_struct_member (struct type *type,
unsigned int *fixed_point_members,
unsigned int *floating_point_members,
- bool *first_member_is_fixed_point)
+ bool *first_member_is_fixed_point,
+ bool *has_long_double)
{
for (int i = 0; i < type->num_fields (); i++)
{
@@ -526,6 +527,12 @@ compute_struct_member (struct type *type,
struct type *field_type = check_typedef (type->field (i).type ());
+ if ((field_type->code () == TYPE_CODE_FLT
+ && field_type->length () == 16)
+ || (field_type->code () == TYPE_CODE_COMPLEX
+ && field_type->length () == 32))
+ *has_long_double = true;
+
if (field_type->code () == TYPE_CODE_INT
|| field_type->code () == TYPE_CODE_BOOL
|| field_type->code () == TYPE_CODE_CHAR
@@ -544,12 +551,79 @@ compute_struct_member (struct type *type,
compute_struct_member (field_type,
fixed_point_members,
floating_point_members,
- first_member_is_fixed_point);
+ first_member_is_fixed_point,
+ has_long_double);
else if (field_type->code () == TYPE_CODE_COMPLEX)
(*floating_point_members) += 2;
}
}
+/* Compute the lengths and offsets of struct member. */
+
+static void
+struct_member_info (struct type *type,
+ unsigned int *member_offsets,
+ unsigned int *member_lens,
+ unsigned int offset,
+ unsigned int *fields)
+{
+ unsigned int count = type->num_fields ();
+ unsigned int i;
+
+ for (i = 0; i < count; ++i)
+ {
+ if (type->field (i).loc_kind () != FIELD_LOC_KIND_BITPOS)
+ continue;
+
+ struct type *field_type = check_typedef (type->field (i).type ());
+ int field_offset
+ = offset + type->field (i).loc_bitpos () / TARGET_CHAR_BIT;
+
+ switch (field_type->code ())
+ {
+ case TYPE_CODE_STRUCT:
+ struct_member_info (field_type, member_offsets, member_lens,
+ field_offset, fields);
+ break;
+
+ case TYPE_CODE_COMPLEX:
+ if (*fields == 0)
+ {
+ /* _Complex float */
+ if (field_type->length () == 8)
+ {
+ member_offsets[0] = field_offset;
+ member_offsets[1] = field_offset + 4;
+ member_lens[0] = member_lens[1] = 4;
+ *fields = 2;
+ }
+ /* _Complex double */
+ else if (field_type->length () == 16)
+ {
+ member_offsets[0] = field_offset;
+ member_offsets[1] = field_offset + 8;
+ member_lens[0] = member_lens[1] = 8;
+ *fields = 2;
+ }
+ }
+ break;
+
+ default:
+ if (*fields < 2)
+ {
+ member_offsets[*fields] = field_offset;
+ member_lens[*fields] = field_type->length ();
+ }
+ (*fields)++;
+ break;
+ }
+
+ /* only has special handling for structures with 1 or 2 fields. */
+ if (*fields > 2)
+ return;
+ }
+}
+
/* Implement the push_dummy_call gdbarch method. */
static CORE_ADDR
@@ -569,6 +643,10 @@ loongarch_push_dummy_call (struct gdbarch *gdbarch,
unsigned int fixed_point_members;
unsigned int floating_point_members;
bool first_member_is_fixed_point;
+ bool has_long_double;
+ unsigned int member_offsets[2];
+ unsigned int member_lens[2];
+ unsigned int fields;
gdb_byte buf[1024] = { 0 };
gdb_byte *addr = buf;
@@ -698,12 +776,55 @@ loongarch_push_dummy_call (struct gdbarch *gdbarch,
fixed_point_members = 0;
floating_point_members = 0;
first_member_is_fixed_point = false;
+ has_long_double = false;
+ member_offsets[0] = member_offsets[1] = 0;
+ member_lens[0] = member_offsets[1] = 0;
+ fields = 0;
compute_struct_member (type,
&fixed_point_members,
&floating_point_members,
- &first_member_is_fixed_point);
-
- if (len > 0 && len <= regsize)
+ &first_member_is_fixed_point,
+ &has_long_double);
+ struct_member_info (type, member_offsets, member_lens, 0, &fields);
+ /* If the structure consists of one floating-point member within
+ FRLEN bits wide, it is passed in an FAR if available. If the
+ structure consists of two floating-point members both within
+ FRLEN bits wide, it is passed in two FARs if available. If the
+ structure consists of one integer member within GRLEN bits wide
+ and one floating-point member within FRLEN bits wide, it is
+ passed in a GAR and an FAR if available. */
+ if (has_long_double == false
+ && ((fixed_point_members == 0 && floating_point_members == 1
+ && far >= 1)
+ || (fixed_point_members == 0 && floating_point_members == 2
+ && far >= 2)
+ || (fixed_point_members == 1 && floating_point_members == 1
+ && far >= 1 && gar >= 1)))
+ {
+ if (fixed_point_members == 0 && floating_point_members == 1)
+ {
+ pass_in_far (regcache, far--, val + member_offsets[0]);
+ }
+ else if (fixed_point_members == 0 && floating_point_members == 2)
+ {
+ pass_in_far (regcache, far--, val + member_offsets[0]);
+ pass_in_far (regcache, far--, val + member_offsets[1]);
+ }
+ else if (fixed_point_members == 1 && floating_point_members == 1)
+ {
+ if (first_member_is_fixed_point == false)
+ {
+ pass_in_far (regcache, far--, val + member_offsets[0]);
+ pass_in_gar (regcache, gar--, val + member_offsets[1]);
+ }
+ else
+ {
+ pass_in_gar (regcache, gar--, val + member_offsets[0]);
+ pass_in_far (regcache, far--, val + member_offsets[1]);
+ }
+ }
+ }
+ else if (len > 0 && len <= regsize)
{
/* The structure has only fixed-point members. */
if (fixed_point_members > 0 && floating_point_members == 0)
@@ -1160,14 +1281,15 @@ loongarch_return_value (struct gdbarch *gdbarch, struct value *function,
unsigned int fixed_point_members;
unsigned int floating_point_members;
bool first_member_is_fixed_point;
+ bool has_long_double;
+ unsigned int member_offsets[2];
+ unsigned int member_lens[2];
+ unsigned int fields;
int a0 = LOONGARCH_A0_REGNUM;
int a1 = LOONGARCH_A0_REGNUM + 1;
int f0 = LOONGARCH_FIRST_FP_REGNUM;
int f1 = LOONGARCH_FIRST_FP_REGNUM + 1;
- if (len > 2 * regsize)
- return RETURN_VALUE_STRUCT_CONVENTION;
-
switch (code)
{
case TYPE_CODE_INT:
@@ -1220,12 +1342,56 @@ loongarch_return_value (struct gdbarch *gdbarch, struct value *function,
fixed_point_members = 0;
floating_point_members = 0;
first_member_is_fixed_point = false;
+ has_long_double = false;
+ member_offsets[0] = member_offsets[1] = 0;
+ member_lens[0] = member_offsets[1] = 0;
+ fields = 0;
compute_struct_member (type,
&fixed_point_members,
&floating_point_members,
- &first_member_is_fixed_point);
-
- if (len > 0 && len <= regsize)
+ &first_member_is_fixed_point,
+ &has_long_double);
+ struct_member_info (type, member_offsets, member_lens, 0, &fields);
+ /* struct consists of one floating-point member;
+ struct consists of two floating-point members;
+ struct consists of one floating-point member
+ and one integer member. */
+ if (has_long_double == false
+ && ((fixed_point_members == 0 && floating_point_members == 1)
+ || (fixed_point_members == 0 && floating_point_members == 2)
+ || (fixed_point_members == 1 && floating_point_members == 1)))
+ {
+ if (fixed_point_members == 0 && floating_point_members == 1)
+ {
+ loongarch_xfer_reg (regcache, f0, member_lens[0], readbuf,
+ writebuf, member_offsets[0]);
+ }
+ else if (fixed_point_members == 0 && floating_point_members == 2)
+ {
+ loongarch_xfer_reg (regcache, f0, member_lens[0], readbuf,
+ writebuf, member_offsets[0]);
+ loongarch_xfer_reg (regcache, f1, member_lens[1], readbuf,
+ writebuf, member_offsets[1]);
+ }
+ else if (fixed_point_members == 1 && floating_point_members == 1)
+ {
+ if (first_member_is_fixed_point == false)
+ {
+ loongarch_xfer_reg (regcache, f0, member_lens[0], readbuf,
+ writebuf, member_offsets[0]);
+ loongarch_xfer_reg (regcache, a0, member_lens[1], readbuf,
+ writebuf, member_offsets[1]);
+ }
+ else
+ {
+ loongarch_xfer_reg (regcache, a0, member_lens[0], readbuf,
+ writebuf, member_offsets[0]);
+ loongarch_xfer_reg (regcache, f0, member_lens[1], readbuf,
+ writebuf, member_offsets[1]);
+ }
+ }
+ }
+ else if (len > 0 && len <= regsize)
{
/* The structure has only fixed-point members. */
if (fixed_point_members > 0 && floating_point_members == 0)
@@ -1338,6 +1504,8 @@ loongarch_return_value (struct gdbarch *gdbarch, struct value *function,
}
}
}
+ else if (len > 2 * regsize)
+ return RETURN_VALUE_STRUCT_CONVENTION;
}
break;
case TYPE_CODE_UNION:
@@ -1352,13 +1520,18 @@ loongarch_return_value (struct gdbarch *gdbarch, struct value *function,
loongarch_xfer_reg (regcache, a0, regsize, readbuf, writebuf, 0);
loongarch_xfer_reg (regcache, a1, len - regsize, readbuf, writebuf, regsize);
}
+ else if (len > 2 * regsize)
+ return RETURN_VALUE_STRUCT_CONVENTION;
break;
case TYPE_CODE_COMPLEX:
- {
- /* The return value is passed in f0 and f1. */
- loongarch_xfer_reg (regcache, f0, len / 2, readbuf, writebuf, 0);
- loongarch_xfer_reg (regcache, f1, len / 2, readbuf, writebuf, len / 2);
- }
+ if (len > 0 && len <= 2 * regsize)
+ {
+ /* The return value is passed in f0 and f1. */
+ loongarch_xfer_reg (regcache, f0, len / 2, readbuf, writebuf, 0);
+ loongarch_xfer_reg (regcache, f1, len / 2, readbuf, writebuf, len / 2);
+ }
+ else if (len > 2 * regsize)
+ return RETURN_VALUE_STRUCT_CONVENTION;
break;
default:
break;
--
2.38.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v2] gdb: LoongArch: Handle special struct in dummy call
2023-10-08 7:32 [PATCH v2] gdb: LoongArch: Handle special struct in dummy call Hui Li
@ 2023-10-11 1:13 ` Tiezhu Yang
0 siblings, 0 replies; 2+ messages in thread
From: Tiezhu Yang @ 2023-10-11 1:13 UTC (permalink / raw)
To: Hui Li, gdb-patches
On 10/08/2023 03:32 PM, Hui Li wrote:
> When execute the following command on LoongArch:
>
> make check-gdb TESTS="gdb.base/infcall-nested-structs-c++.exp"
>
> there exist some failed testcases:
>
> === gdb Summary ===
>
> # of expected passes 5533
> # of unexpected failures 367
>
> The root cause is related with a struct containing floating-point
> members as function argument or return value for a dummy call.
...
>
> With this patch, there are no failed testcases:
>
> make check-gdb TESTS="gdb.base/infcall-nested-structs-c++.exp"
>
> === gdb Summary ===
>
> # of expected passes 5900
>
> Signed-off-by: Hui Li <lihui@loongson.cn>
Thanks for the patch, looks good to me.
Tested on LoongArch, pushed.
Thanks,
Tiezhu
^ permalink raw reply [flat|nested] 2+ messages in thread
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