MatCat.OpenSource/8sa1-binutils-gdb
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read/write_pieced_value: Respect value parent's offset

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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.
This commit is contained in:
Andreas Arnez 2017-06-13 15:20:27 +02:00
parent 805acca042
commit af547a9614
2 changed files with 10 additions and 2 deletions
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6
gdb/ChangeLog
View File

@ -1,3 +1,9 @@
2017-06-13 Andreas Arnez <arnez@linux.vnet.ibm.com>
* dwarf2loc.c (read_pieced_value): Respect parent value's offset
when targeting a bit-field.
(write_pieced_value): Likewise.
2017-06-13 Andreas Arnez <arnez@linux.vnet.ibm.com>
* dwarf2loc.c (struct piece_closure) <addr_size>: Remove field.

6
gdb/dwarf2loc.c
View File

@ -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