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Regression for i686 gdb.dwarf2/pieces-optimized-out.exp 

Git 9a0dc9e3 regressed gdb.dwarf2/pieces-optimized-out.exp, visible on
i686 (the test doesn't run on x86_64):

 (gdb) p s
 -$1 = {a = 5, b = <optimized out>, c = <optimized out>, d = <optimized out>}
 +$1 = {a = 5, b = <optimized out>, c = 0, d = 0}
 -(gdb) PASS: gdb.dwarf2/pieces-optimized-out.exp: print s
 +(gdb) FAIL: gdb.dwarf2/pieces-optimized-out.exp: print s

The regression was caused by this removal in cp-valprint.c:

  @@ -293,12 +293,6 @@ cp_print_value_fields (struct type *type, struct type *real_type,
		  {
		    fputs_filtered (_("<synthetic pointer>"), stream);
		  }
  -             else if (!value_bits_valid (val,
  -                                         TYPE_FIELD_BITPOS (type, i),
  -                                         TYPE_FIELD_BITSIZE (type, i)))
  -               {
  -                 val_print_optimized_out (val, stream);
  -               }
		else
		  {
		    struct value_print_options opts = *options;

The idea was that we'd just fallback to calling value_field_bitfield,
which handles unavailable values (in unpack_value_bits_as_long_1) so
should be able to handle optimized out values too.  Alas, it doesn't.
This is currently a bit too messy.  Instead of teaching
unpack_value_bits_as_long_1 about optimized out bits, let's bite the
bullet and teach the value code to handle partially optimized out
bitfield, by having it unpack a bitfield and then propagate the range
metadata.  Turns out the resulting code looks simpler and clearer.

Tested on x86_64 Fedora 20, -m64/-m32.

gdb/ChangeLog:

	* value.c (value_ranges_copy_adjusted): New function, factored out
	from ...
	(value_contents_copy_raw): ... here.
	(unpack_value_bits_as_long_1): Rename back to ...
	(unpack_bits_as_long): ... this.  Remove 'original_value' and
	'result' parameters.  Change return type to LONGEST.
	(unpack_value_bits_as_long): Delete.
	(unpack_value_field_as_long_1): Delete.
	(unpack_value_field_as_long, unpack_field_as_long): Reimplement.
	(unpack_value_bitfield): New function.
	(value_field_bitfield): Reimplement using unpack_value_bitfield.
	(value_fetch_lazy): Use unpack_value_bitfield.
	* value.h (unpack_value_bits_as_long): Delete declaration.
This commit is contained in:
Pedro Alves 2014-09-04 12:12:41 +01:00
parent b138b7a9ed
commit 4875ffdbda
3 changed files with 125 additions and 125 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
gdb/ChangeLog
View File

@ -1,3 +1,19 @@
2014-09-04 Pedro Alves <palves@redhat.com>
* value.c (value_ranges_copy_adjusted): New function, factored out
from ...
(value_contents_copy_raw): ... here.
(unpack_value_bits_as_long_1): Rename back to ...
(unpack_bits_as_long): ... this. Remove 'original_value' and
'result' parameters. Change return type to LONGEST.
(unpack_value_bits_as_long): Delete.
(unpack_value_field_as_long_1): Delete.
(unpack_value_field_as_long, unpack_field_as_long): Reimplement.
(unpack_value_bitfield): New function.
(value_field_bitfield): Reimplement using unpack_value_bitfield.
(value_fetch_lazy): Use unpack_value_bitfield.
* value.h (unpack_value_bits_as_long): Delete declaration.
2014-09-03 Sasha Smundak <asmundak@google.com>
* python/py-frame.c (frapy_read_register): New function.

227
gdb/value.c
View File

@ -1219,6 +1219,22 @@ ranges_copy_adjusted (VEC (range_s) **dst_range, int dst_bit_offset,
}
}
/* Copy the ranges metadata in SRC that overlaps [SRC_BIT_OFFSET,
SRC_BIT_OFFSET+BIT_LENGTH) into DST, adjusted. */
static void
value_ranges_copy_adjusted (struct value *dst, int dst_bit_offset,
const struct value *src, int src_bit_offset,
int bit_length)
{
ranges_copy_adjusted (&dst->unavailable, dst_bit_offset,
src->unavailable, src_bit_offset,
bit_length);
ranges_copy_adjusted (&dst->optimized_out, dst_bit_offset,
src->optimized_out, src_bit_offset,
bit_length);
}
/* Copy LENGTH bytes of SRC value's (all) contents
(value_contents_all) starting at SRC_OFFSET, into DST value's (all)
contents, starting at DST_OFFSET. If unavailable contents are
@ -1261,13 +1277,9 @@ value_contents_copy_raw (struct value *dst, int dst_offset,
dst_bit_offset = dst_offset * TARGET_CHAR_BIT;
bit_length = length * TARGET_CHAR_BIT;
ranges_copy_adjusted (&dst->unavailable, dst_bit_offset,
src->unavailable, src_bit_offset,
bit_length);
ranges_copy_adjusted (&dst->optimized_out, dst_bit_offset,
src->optimized_out, src_bit_offset,
bit_length);
value_ranges_copy_adjusted (dst, dst_bit_offset,
src, src_bit_offset,
bit_length);
}
/* Copy LENGTH bytes of SRC value's (all) contents
@ -3105,16 +3117,24 @@ value_fn_field (struct value **arg1p, struct fn_field *f,
/* Helper function for both unpack_value_bits_as_long and
unpack_bits_as_long. See those functions for more details on the
interface; the only difference is that this function accepts either
a NULL or a non-NULL ORIGINAL_VALUE. */
/* Unpack a bitfield of the specified FIELD_TYPE, from the object at
VALADDR, and store the result in *RESULT.
The bitfield starts at BITPOS bits and contains BITSIZE bits.
static int
unpack_value_bits_as_long_1 (struct type *field_type, const gdb_byte *valaddr,
int embedded_offset, int bitpos, int bitsize,
const struct value *original_value,
LONGEST *result)
Extracting bits depends on endianness of the machine. Compute the
number of least significant bits to discard. For big endian machines,
we compute the total number of bits in the anonymous object, subtract
off the bit count from the MSB of the object to the MSB of the
bitfield, then the size of the bitfield, which leaves the LSB discard
count. For little endian machines, the discard count is simply the
number of bits from the LSB of the anonymous object to the LSB of the
bitfield.
If the field is signed, we also do sign extension. */
static LONGEST
unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr,
int bitpos, int bitsize)
{
enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (field_type));
ULONGEST val;
@ -3133,12 +3153,7 @@ unpack_value_bits_as_long_1 (struct type *field_type, const gdb_byte *valaddr,
read_offset = bitpos / 8;
if (original_value != NULL
&& !value_bits_available (original_value, embedded_offset + bitpos,
bitsize))
return 0;
val = extract_unsigned_integer (valaddr + embedded_offset + read_offset,
val = extract_unsigned_integer (valaddr + read_offset,
bytes_read, byte_order);
/* Extract bits. See comment above. */
@ -3165,60 +3180,7 @@ unpack_value_bits_as_long_1 (struct type *field_type, const gdb_byte *valaddr,
}
}
*result = val;
return 1;
}
/* Unpack a bitfield of the specified FIELD_TYPE, from the object at
VALADDR + EMBEDDED_OFFSET, and store the result in *RESULT.
VALADDR points to the contents of ORIGINAL_VALUE, which must not be
NULL. The bitfield starts at BITPOS bits and contains BITSIZE
bits.
Returns false if the value contents are unavailable, otherwise
returns true, indicating a valid value has been stored in *RESULT.
Extracting bits depends on endianness of the machine. Compute the
number of least significant bits to discard. For big endian machines,
we compute the total number of bits in the anonymous object, subtract
off the bit count from the MSB of the object to the MSB of the
bitfield, then the size of the bitfield, which leaves the LSB discard
count. For little endian machines, the discard count is simply the
number of bits from the LSB of the anonymous object to the LSB of the
bitfield.
If the field is signed, we also do sign extension. */
int
unpack_value_bits_as_long (struct type *field_type, const gdb_byte *valaddr,
int embedded_offset, int bitpos, int bitsize,
const struct value *original_value,
LONGEST *result)
{
gdb_assert (original_value != NULL);
return unpack_value_bits_as_long_1 (field_type, valaddr, embedded_offset,
bitpos, bitsize, original_value, result);
}
/* Unpack a field FIELDNO of the specified TYPE, from the object at
VALADDR + EMBEDDED_OFFSET. VALADDR points to the contents of
ORIGINAL_VALUE. See unpack_value_bits_as_long for more
details. */
static int
unpack_value_field_as_long_1 (struct type *type, const gdb_byte *valaddr,
int embedded_offset, int fieldno,
const struct value *val, LONGEST *result)
{
int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
return unpack_value_bits_as_long_1 (field_type, valaddr, embedded_offset,
bitpos, bitsize, val,
result);
return val;
}
/* Unpack a field FIELDNO of the specified TYPE, from the object at
@ -3231,51 +3193,95 @@ unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr,
int embedded_offset, int fieldno,
const struct value *val, LONGEST *result)
{
int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
int bit_offset;
gdb_assert (val != NULL);
return unpack_value_field_as_long_1 (type, valaddr, embedded_offset,
fieldno, val, result);
bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
if (value_bits_any_optimized_out (val, bit_offset, bitsize)
|| !value_bits_available (val, bit_offset, bitsize))
return 0;
*result = unpack_bits_as_long (field_type, valaddr + embedded_offset,
bitpos, bitsize);
return 1;
}
/* Unpack a field FIELDNO of the specified TYPE, from the anonymous
object at VALADDR. See unpack_value_bits_as_long for more details.
This function differs from unpack_value_field_as_long in that it
operates without a struct value object. */
object at VALADDR. See unpack_bits_as_long for more details. */
LONGEST
unpack_field_as_long (struct type *type, const gdb_byte *valaddr, int fieldno)
{
LONGEST result;
int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
unpack_value_field_as_long_1 (type, valaddr, 0, fieldno, NULL, &result);
return result;
return unpack_bits_as_long (field_type, valaddr, bitpos, bitsize);
}
/* Unpack a bitfield of BITSIZE bits found at BITPOS in the object at
VALADDR + EMBEDDEDOFFSET that has the type of DEST_VAL and store
the contents in DEST_VAL, zero or sign extending if the type of
DEST_VAL is wider than BITSIZE. VALADDR points to the contents of
VAL. If the VAL's contents required to extract the bitfield from
are unavailable/optimized out, DEST_VAL is correspondingly
marked unavailable/optimized out. */
static void
unpack_value_bitfield (struct value *dest_val,
int bitpos, int bitsize,
const gdb_byte *valaddr, int embedded_offset,
const struct value *val)
{
enum bfd_endian byte_order;
int src_bit_offset;
int dst_bit_offset;
LONGEST num;
struct type *field_type = value_type (dest_val);
/* First, unpack and sign extend the bitfield as if it was wholly
available. Invalid/unavailable bits are read as zero, but that's
OK, as they'll end up marked below. */
byte_order = gdbarch_byte_order (get_type_arch (field_type));
num = unpack_bits_as_long (field_type, valaddr + embedded_offset,
bitpos, bitsize);
store_signed_integer (value_contents_raw (dest_val),
TYPE_LENGTH (field_type), byte_order, num);
/* Now copy the optimized out / unavailability ranges to the right
bits. */
src_bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
if (byte_order == BFD_ENDIAN_BIG)
dst_bit_offset = TYPE_LENGTH (field_type) * TARGET_CHAR_BIT - bitsize;
else
dst_bit_offset = 0;
value_ranges_copy_adjusted (dest_val, dst_bit_offset,
val, src_bit_offset, bitsize);
}
/* Return a new value with type TYPE, which is FIELDNO field of the
object at VALADDR + EMBEDDEDOFFSET. VALADDR points to the contents
of VAL. If the VAL's contents required to extract the bitfield
from are unavailable, the new value is correspondingly marked as
unavailable. */
from are unavailable/optimized out, the new value is
correspondingly marked unavailable/optimized out. */
struct value *
value_field_bitfield (struct type *type, int fieldno,
const gdb_byte *valaddr,
int embedded_offset, const struct value *val)
{
LONGEST l;
int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
struct value *res_val = allocate_value (TYPE_FIELD_TYPE (type, fieldno));
if (!unpack_value_field_as_long (type, valaddr, embedded_offset, fieldno,
val, &l))
{
struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
struct value *retval = allocate_value (field_type);
mark_value_bytes_unavailable (retval, 0, TYPE_LENGTH (field_type));
return retval;
}
else
{
return value_from_longest (TYPE_FIELD_TYPE (type, fieldno), l);
}
unpack_value_bitfield (res_val, bitpos, bitsize,
valaddr, embedded_offset, val);
return res_val;
}
/* Modify the value of a bitfield. ADDR points to a block of memory in
@ -3757,30 +3763,15 @@ value_fetch_lazy (struct value *val)
word, but we have no way to record that just specific bits of a
value have been fetched. */
struct type *type = check_typedef (value_type (val));
enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
struct value *parent = value_parent (val);
LONGEST offset = value_offset (val);
LONGEST num;
if (value_lazy (parent))
value_fetch_lazy (parent);
if (value_bits_any_optimized_out (parent,
TARGET_CHAR_BIT * offset + value_bitpos (val),
value_bitsize (val)))
mark_value_bytes_optimized_out (val, value_embedded_offset (val),
TYPE_LENGTH (type));
else if (!unpack_value_bits_as_long (value_type (val),
value_contents_for_printing (parent),
offset,
value_bitpos (val),
value_bitsize (val), parent, &num))
mark_value_bytes_unavailable (val,
value_embedded_offset (val),
TYPE_LENGTH (type));
else
store_signed_integer (value_contents_raw (val), TYPE_LENGTH (type),
byte_order, num);
unpack_value_bitfield (val,
value_bitpos (val), value_bitsize (val),
value_contents_for_printing (parent),
value_offset (val), parent);
}
else if (VALUE_LVAL (val) == lval_memory)
{

7
gdb/value.h
View File

@ -606,13 +606,6 @@ extern DOUBLEST unpack_double (struct type *type, const gdb_byte *valaddr,
int *invp);
extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
extern int unpack_value_bits_as_long (struct type *field_type,
const gdb_byte *valaddr,
int embedded_offset, int bitpos,
int bitsize,
const struct value *original_value,
LONGEST *result);
extern LONGEST unpack_field_as_long (struct type *type,
const gdb_byte *valaddr,
int fieldno);