168 lines
5.5 KiB
Diff
168 lines
5.5 KiB
Diff
commit 65d84b76164dc8ec1a1f0f0e0fd41667065ffd4e
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Author: Andreas Arnez <arnez@linux.vnet.ibm.com>
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Date: Tue Jun 13 15:20:31 2017 +0200
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Respect piece offset for DW_OP_bit_piece
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So far GDB ignores the piece offset of all kinds of DWARF bit
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pieces (DW_OP_bit_piece) and treats such pieces as if the offset was zero.
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This is fixed, and an appropriate test is added.
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gdb/ChangeLog:
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* dwarf2loc.c (read_pieced_value): Respect the piece offset, as
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given by DW_OP_bit_piece.
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(write_pieced_value): Likewise.
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Andreas Arnez <arnez@linux.vnet.ibm.com>
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* gdb.dwarf2/var-access.exp: Add test for composite location with
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nonzero piece offsets.
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### a/gdb/ChangeLog
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### b/gdb/ChangeLog
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## -1,5 +1,11 @@
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2017-06-13 Andreas Arnez <arnez@linux.vnet.ibm.com>
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+ * dwarf2loc.c (read_pieced_value): Respect the piece offset, as
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+ given by DW_OP_bit_piece.
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+ (write_pieced_value): Likewise.
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+
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+2017-06-13 Andreas Arnez <arnez@linux.vnet.ibm.com>
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+
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* dwarf2loc.c (read_pieced_value): Move the buffer allocation and
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some other preparations to the places where sufficient information
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is available.
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--- a/gdb/dwarf2loc.c
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+++ b/gdb/dwarf2loc.c
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@@ -1824,11 +1824,14 @@ read_pieced_value (struct value *v)
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int optim, unavail;
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if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
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- && p->size < reg_bits)
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+ && p->offset + p->size < reg_bits)
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{
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/* Big-endian, and we want less than full size. */
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- source_offset_bits += reg_bits - p->size;
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+ source_offset_bits += reg_bits - (p->offset + p->size);
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}
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+ else
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+ source_offset_bits += p->offset;
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+
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this_size = bits_to_bytes (source_offset_bits, this_size_bits);
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buffer.reserve (this_size);
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@@ -1851,6 +1854,7 @@ read_pieced_value (struct value *v)
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break;
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case DWARF_VALUE_MEMORY:
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+ source_offset_bits += p->offset;
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this_size = bits_to_bytes (source_offset_bits, this_size_bits);
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buffer.reserve (this_size);
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@@ -1871,12 +1875,15 @@ read_pieced_value (struct value *v)
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= 8 * TYPE_LENGTH (value_type (p->v.value));
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/* Use zeroes if piece reaches beyond stack value. */
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- if (p->size > stack_value_size_bits)
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+ if (p->offset + p->size > stack_value_size_bits)
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break;
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/* Piece is anchored at least significant bit end. */
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if (gdbarch_byte_order (objfile_gdbarch) == BFD_ENDIAN_BIG)
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- source_offset_bits += stack_value_size_bits - p->size;
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+ source_offset_bits += (stack_value_size_bits
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+ - p->offset - p->size);
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+ else
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+ source_offset_bits += p->offset;
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copy_bitwise (contents, dest_offset_bits,
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value_contents_all (p->v.value),
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@@ -1891,6 +1898,7 @@ read_pieced_value (struct value *v)
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size_t n = this_size_bits;
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/* Cut off at the end of the implicit value. */
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+ source_offset_bits += p->offset;
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if (source_offset_bits >= literal_size_bits)
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break;
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if (n > literal_size_bits - source_offset_bits)
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@@ -1981,11 +1989,14 @@ write_pieced_value (struct value *to, struct value *from)
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ULONGEST reg_bits = 8 * register_size (arch, gdb_regnum);
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if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
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- && p->size <= reg_bits)
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+ && p->offset + p->size < reg_bits)
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{
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/* Big-endian, and we want less than full size. */
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- dest_offset_bits += reg_bits - p->size;
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+ dest_offset_bits += reg_bits - (p->offset + p->size);
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}
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+ else
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+ dest_offset_bits += p->offset;
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+
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this_size = bits_to_bytes (dest_offset_bits, this_size_bits);
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buffer.reserve (this_size);
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@@ -2023,6 +2034,8 @@ write_pieced_value (struct value *to, struct value *from)
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break;
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case DWARF_VALUE_MEMORY:
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{
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+ dest_offset_bits += p->offset;
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+
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CORE_ADDR start_addr = p->v.mem.addr + dest_offset_bits / 8;
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if (dest_offset_bits % 8 == 0 && this_size_bits % 8 == 0
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--- a/gdb/testsuite/gdb.dwarf2/var-access.exp
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+++ b/gdb/testsuite/gdb.dwarf2/var-access.exp
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@@ -228,6 +228,24 @@ Dwarf::assemble $asm_file {
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piece 1
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} SPECIAL_expr}
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}
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+ # One piece per bitfield, using piece offsets: 32 bits of
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+ # an implicit value, 9 bits of a stack value, 13 bits of
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+ # r0, and 10 bits of buf.
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+ DW_TAG_variable {
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+ {name "t3"}
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+ {type :$struct_t_label}
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+ {location {
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+ implicit_value 0x12 0x34 0x56 0x78 0x9a
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+ bit_piece 32 4
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+ const2s -280
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+ stack_value
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+ bit_piece 9 2
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+ regx [lindex $dwarf_regnum 0]
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+ bit_piece 13 14
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+ addr $buf_var
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+ bit_piece 10 42
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+ } SPECIAL_expr}
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+ }
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}
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}
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}
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@@ -304,3 +322,24 @@ gdb_test_no_output "set var t2.y = 2641"
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gdb_test_no_output "set var t2.z = -400"
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gdb_test_no_output "set var t2.x = 200"
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gdb_test "print t2.x + t2.y + t2.z" " = 2441"
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+
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+# Bitfield access through pieces with nonzero piece offsets.
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+gdb_test_no_output "set var \$[lindex $regname 0] = 0xa8000" \
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+ "init reg for t3.y"
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+gdb_test_no_output "set var *(char \[2\] *) (a + 5) = { 70, 82 }" \
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+ "init mem for t3.z"
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+switch $endian {
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+ little {set val "u = -1484430527, x = -70, y = 42, z = 145"}
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+ big {set val "u = 591751049, x = -70, y = 42, z = 101"}
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+}
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+gdb_test "print t3" " = \\{$val\\}" \
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+ "initialized t3 from reg and mem"
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+gdb_test_no_output "set var t3.y = -1" \
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+ "overwrite t3.y"
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+gdb_test "print/x \$[lindex $regname 0]" " = 0x7ffc000" \
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+ "verify t3.y through reg"
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+gdb_test_no_output "set var t3.z = -614" \
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+ "overwrite t3.z"
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+switch $endian {big {set val "0x59, 0xa2"} little {set val "0x6a, 0x56"}}
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+gdb_test "print/x *(char \[2\] *) (a + 5)" " = \\{$val\\}" \
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+ "verify t3.z through mem"
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