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gdb: LoongArch: Handle special struct in dummy call

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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>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
This commit is contained in:
Hui Li
2023-06-28 17:33:05 +08:00
committed by Tiezhu Yang
parent 635b2dd919
commit 95735b00a0
1 changed files with 189 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

205
gdb/loongarch-tdep.c
View File

@@ -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;