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read/write_pieced_value: Remove unnecessary variable copies 

In read_pieced_value's main loop, the variables `dest_offset_bits' and
`source_offset_bits' are basically just copies of `offset' and
`bits_to_skip', respectively.  In write_pieced_value the copies are
reversed.  This is not very helpful when trying to keep the logic between
these functions in sync.  Since the copies are unnecessary, this patch
just removes them.

gdb/ChangeLog:

	* dwarf2loc.c (read_pieced_value): Remove unnecessary variables
	dest_offset_bits and source_offset_bits.
	(write_pieced_value): Likewise.
This commit is contained in:
Andreas Arnez 2017-06-13 15:20:31 +02:00
parent 65d84b7616
commit f236533e3c
2 changed files with 58 additions and 68 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): Remove unnecessary variables
dest_offset_bits and source_offset_bits.
(write_pieced_value): Likewise.
2017-06-13 Andreas Arnez <arnez@linux.vnet.ibm.com>
* dwarf2loc.c (read_pieced_value): Respect the piece offset, as

120
gdb/dwarf2loc.c
View File

@ -1790,25 +1790,16 @@ read_pieced_value (struct value *v)
else
max_offset = 8 * TYPE_LENGTH (value_type (v));
for (i = 0; i < c->n_pieces && offset < max_offset; i++)
/* Advance to the first non-skipped piece. */
for (i = 0; i < c->n_pieces && bits_to_skip >= c->pieces[i].size; i++)
bits_to_skip -= c->pieces[i].size;
for (; i < c->n_pieces && offset < max_offset; i++)
{
struct dwarf_expr_piece *p = &c->pieces[i];
size_t this_size, this_size_bits;
long dest_offset_bits, source_offset_bits;
/* Compute size, source, and destination offsets for copying, in
bits. */
this_size_bits = p->size;
if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
{
bits_to_skip -= this_size_bits;
continue;
}
source_offset_bits = bits_to_skip;
this_size_bits -= bits_to_skip;
bits_to_skip = 0;
dest_offset_bits = offset;
this_size_bits = p->size - bits_to_skip;
if (this_size_bits > max_offset - offset)
this_size_bits = max_offset - offset;
@ -1827,16 +1818,16 @@ read_pieced_value (struct value *v)
&& p->offset + p->size < reg_bits)
{
/* Big-endian, and we want less than full size. */
source_offset_bits += reg_bits - (p->offset + p->size);
bits_to_skip += reg_bits - (p->offset + p->size);
}
else
source_offset_bits += p->offset;
bits_to_skip += p->offset;
this_size = bits_to_bytes (source_offset_bits, this_size_bits);
this_size = bits_to_bytes (bits_to_skip, this_size_bits);
buffer.reserve (this_size);
if (!get_frame_register_bytes (frame, gdb_regnum,
source_offset_bits / 8,
bits_to_skip / 8,
this_size, buffer.data (),
&optim, &unavail))
{
@ -1846,24 +1837,23 @@ read_pieced_value (struct value *v)
mark_value_bits_unavailable (v, offset, this_size_bits);
break;
}
copy_bitwise (contents, dest_offset_bits,
buffer.data (), source_offset_bits % 8,
copy_bitwise (contents, offset,
buffer.data (), bits_to_skip % 8,
this_size_bits, bits_big_endian);
}
break;
case DWARF_VALUE_MEMORY:
source_offset_bits += p->offset;
this_size = bits_to_bytes (source_offset_bits, this_size_bits);
bits_to_skip += p->offset;
this_size = bits_to_bytes (bits_to_skip, this_size_bits);
buffer.reserve (this_size);
read_value_memory (v, offset,
p->v.mem.in_stack_memory,
p->v.mem.addr + source_offset_bits / 8,
p->v.mem.addr + bits_to_skip / 8,
buffer.data (), this_size);
copy_bitwise (contents, dest_offset_bits,
buffer.data (), source_offset_bits % 8,
copy_bitwise (contents, offset,
buffer.data (), bits_to_skip % 8,
this_size_bits, bits_big_endian);
break;
@ -1880,14 +1870,13 @@ read_pieced_value (struct value *v)
/* Piece is anchored at least significant bit end. */
if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
source_offset_bits += (stack_value_size_bits
- p->offset - p->size);
bits_to_skip += stack_value_size_bits - p->offset - p->size;
else
source_offset_bits += p->offset;
bits_to_skip += p->offset;
copy_bitwise (contents, dest_offset_bits,
copy_bitwise (contents, offset,
value_contents_all (p->v.value),
source_offset_bits,
bits_to_skip,
this_size_bits, bits_big_endian);
}
break;
@ -1898,14 +1887,14 @@ read_pieced_value (struct value *v)
size_t n = this_size_bits;
/* Cut off at the end of the implicit value. */
source_offset_bits += p->offset;
if (source_offset_bits >= literal_size_bits)
bits_to_skip += p->offset;
if (bits_to_skip >= literal_size_bits)
break;
if (n > literal_size_bits - source_offset_bits)
n = literal_size_bits - source_offset_bits;
if (n > literal_size_bits - bits_to_skip)
n = literal_size_bits - bits_to_skip;
copy_bitwise (contents, dest_offset_bits,
p->v.literal.data, source_offset_bits,
copy_bitwise (contents, offset,
p->v.literal.data, bits_to_skip,
n, bits_big_endian);
}
break;
@ -1924,6 +1913,7 @@ read_pieced_value (struct value *v)
}
offset += this_size_bits;
bits_to_skip = 0;
}
}
@ -1959,23 +1949,16 @@ write_pieced_value (struct value *to, struct value *from)
else
max_offset = 8 * TYPE_LENGTH (value_type (to));
for (i = 0; i < c->n_pieces && offset < max_offset; i++)
/* Advance to the first non-skipped piece. */
for (i = 0; i < c->n_pieces && bits_to_skip >= c->pieces[i].size; i++)
bits_to_skip -= c->pieces[i].size;
for (; i < c->n_pieces && offset < max_offset; i++)
{
struct dwarf_expr_piece *p = &c->pieces[i];
size_t this_size_bits, this_size;
long dest_offset_bits, source_offset_bits;
this_size_bits = p->size;
if (bits_to_skip > 0 && bits_to_skip >= this_size_bits)
{
bits_to_skip -= this_size_bits;
continue;
}
dest_offset_bits = bits_to_skip;
this_size_bits -= bits_to_skip;
bits_to_skip = 0;
source_offset_bits = offset;
this_size_bits = p->size - bits_to_skip;
if (this_size_bits > max_offset - offset)
this_size_bits = max_offset - offset;
@ -1992,22 +1975,22 @@ write_pieced_value (struct value *to, struct value *from)
&& p->offset + p->size < reg_bits)
{
/* Big-endian, and we want less than full size. */
dest_offset_bits += reg_bits - (p->offset + p->size);
bits_to_skip += reg_bits - (p->offset + p->size);
}
else
dest_offset_bits += p->offset;
bits_to_skip += p->offset;
this_size = bits_to_bytes (dest_offset_bits, this_size_bits);
this_size = bits_to_bytes (bits_to_skip, this_size_bits);
buffer.reserve (this_size);
if (dest_offset_bits % 8 != 0 || this_size_bits % 8 != 0)
if (bits_to_skip % 8 != 0 || this_size_bits % 8 != 0)
{
/* Data is copied non-byte-aligned into the register.
Need some bits from original register value. */
int optim, unavail;
if (!get_frame_register_bytes (frame, gdb_regnum,
dest_offset_bits / 8,
bits_to_skip / 8,
this_size, buffer.data (),
&optim, &unavail))
{
@ -2024,34 +2007,34 @@ write_pieced_value (struct value *to, struct value *from)
}
}
copy_bitwise (buffer.data (), dest_offset_bits % 8,
contents, source_offset_bits,
copy_bitwise (buffer.data (), bits_to_skip % 8,
contents, offset,
this_size_bits, bits_big_endian);
put_frame_register_bytes (frame, gdb_regnum,
dest_offset_bits / 8,
bits_to_skip / 8,
this_size, buffer.data ());
}
break;
case DWARF_VALUE_MEMORY:
{
dest_offset_bits += p->offset;
bits_to_skip += p->offset;
CORE_ADDR start_addr = p->v.mem.addr + dest_offset_bits / 8;
CORE_ADDR start_addr = p->v.mem.addr + bits_to_skip / 8;
if (dest_offset_bits % 8 == 0 && this_size_bits % 8 == 0
&& source_offset_bits % 8 == 0)
if (bits_to_skip % 8 == 0 && this_size_bits % 8 == 0
&& offset % 8 == 0)
{
/* Everything is byte-aligned; no buffer needed. */
write_memory (start_addr,
contents + source_offset_bits / 8,
contents + offset / 8,
this_size_bits / 8);
break;
}
this_size = bits_to_bytes (dest_offset_bits, this_size_bits);
this_size = bits_to_bytes (bits_to_skip, this_size_bits);
buffer.reserve (this_size);
if (dest_offset_bits % 8 != 0 || this_size_bits % 8 != 0)
if (bits_to_skip % 8 != 0 || this_size_bits % 8 != 0)
{
if (this_size <= 8)
{
@ -2068,8 +2051,8 @@ write_pieced_value (struct value *to, struct value *from)
}
}
copy_bitwise (buffer.data (), dest_offset_bits % 8,
contents, source_offset_bits,
copy_bitwise (buffer.data (), bits_to_skip % 8,
contents, offset,
this_size_bits, bits_big_endian);
write_memory (start_addr, buffer.data (), this_size);
}
@ -2079,6 +2062,7 @@ write_pieced_value (struct value *to, struct value *from)
break;
}
offset += this_size_bits;
bits_to_skip = 0;
}
}