[v2,06/19] read/write_pieced_value: Respect value parent's offset
Commit Message
In the case of targeting a bit-field, read_pieced_value and
write_pieced_value calculate the number of bits preceding the bit-field
without considering the relative offset of the value's parent. This is
relevant for a structure variable like this:
struct s {
uint64_t foo;
struct {
uint32_t bar;
uint32_t bf : 10; /* <-- target bit-field */
} baz;
} s;
In this scenario, if 'val' is a GDB value representing s.baz.bf,
val->parent represents the whole s.baz structure, and the following holds:
- value_offset (val) == sizeof s.baz.bar == 4
- value_offset (val->parent) == sizeof s.foo == 8
The current logic would only use value_offset(val), resulting in the wrong
offset into the target value. This is fixed.
gdb/ChangeLog:
* dwarf2loc.c (read_pieced_value): Respect parent value's offset
when targeting a bit-field.
(write_pieced_value): Likewise.
---
gdb/dwarf2loc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
Comments
Andreas Arnez <arnez@linux.vnet.ibm.com> writes:
> * dwarf2loc.c (read_pieced_value): Respect parent value's offset
> when targeting a bit-field.
> (write_pieced_value): Likewise.
LGTM.
@@ -1776,7 +1776,8 @@ read_pieced_value (struct value *v)
bits_to_skip = 8 * value_offset (v);
if (value_bitsize (v))
{
- bits_to_skip += value_bitpos (v);
+ bits_to_skip += (8 * value_offset (value_parent (v))
+ + value_bitpos (v));
type_len = value_bitsize (v);
}
else
@@ -1946,7 +1947,8 @@ write_pieced_value (struct value *to, struct value *from)
bits_to_skip = 8 * value_offset (to);
if (value_bitsize (to))
{
- bits_to_skip += value_bitpos (to);
+ bits_to_skip += (8 * value_offset (value_parent (to))
+ + value_bitpos (to));
type_len = value_bitsize (to);
}
else