Hi,
DWARF-5 has new form DW_FORM_data16. The problem is that GDB cannot pass
16-byte constant as a constant value as that would require GDB to use GCC
extension __int128.
Formerly such data was coded as DW_FORM_block* so GDB still decodes
DW_FORM_data16 like DW_FORM_block*.
Jan
gdb/ChangeLog
2017-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2read.c (skip_one_die, read_attribute_value)
(dwarf2_const_value_attr, dump_die_shallow)
(dwarf2_get_attr_constant_value, dwarf2_fetch_constant_bytes)
(skip_form_bytes, attr_form_is_constant): Handle DW_FORM_data16.
gdb/testsuite/ChangeLog
2017-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.dwarf2/formdata16.c: New file.
* gdb.dwarf2/formdata16.exp: New file.
* lib/dwarf.exp (Dwarf): Add DW_FORM_data16.
---
gdb/dwarf2read.c | 25 ++++++++++
gdb/testsuite/gdb.dwarf2/formdata16.c | 22 +++++++++
gdb/testsuite/gdb.dwarf2/formdata16.exp | 77 +++++++++++++++++++++++++++++++
gdb/testsuite/lib/dwarf.exp | 4 ++
4 files changed, 127 insertions(+), 1 deletion(-)
create mode 100644 gdb/testsuite/gdb.dwarf2/formdata16.c
create mode 100644 gdb/testsuite/gdb.dwarf2/formdata16.exp
@@ -7414,6 +7414,9 @@ skip_one_die (const struct die_reader_specs *reader, const gdb_byte *info_ptr,
case DW_FORM_ref_sig8:
info_ptr += 8;
break;
+ case DW_FORM_data16:
+ info_ptr += 16;
+ break;
case DW_FORM_string:
read_direct_string (abfd, info_ptr, &bytes_read);
info_ptr += bytes_read;
@@ -16553,6 +16556,13 @@ read_attribute_value (const struct die_reader_specs *reader,
DW_UNSND (attr) = read_8_bytes (abfd, info_ptr);
info_ptr += 8;
break;
+ case DW_FORM_data16:
+ blk = dwarf_alloc_block (cu);
+ blk->size = 16;
+ blk->data = read_n_bytes (abfd, info_ptr, 16);
+ info_ptr += 16;
+ DW_BLOCK (attr) = blk;
+ break;
case DW_FORM_sec_offset:
DW_UNSND (attr) = read_offset (abfd, info_ptr, &cu->header, &bytes_read);
info_ptr += bytes_read;
@@ -19296,6 +19306,7 @@ dwarf2_const_value_attr (const struct attribute *attr, struct type *type,
case DW_FORM_block4:
case DW_FORM_block:
case DW_FORM_exprloc:
+ case DW_FORM_data16:
blk = DW_BLOCK (attr);
if (TYPE_LENGTH (type) != blk->size)
dwarf2_const_value_length_mismatch_complaint (name, blk->size,
@@ -20250,6 +20261,9 @@ dump_die_shallow (struct ui_file *f, int indent, struct die_info *die)
fprintf_unfiltered (f, "expression: size %s",
pulongest (DW_BLOCK (&die->attrs[i])->size));
break;
+ case DW_FORM_data16:
+ fprintf_unfiltered (f, "constant of 16 bytes");
+ break;
case DW_FORM_ref_addr:
fprintf_unfiltered (f, "ref address: ");
fputs_filtered (hex_string (DW_UNSND (&die->attrs[i])), f);
@@ -20411,6 +20425,7 @@ dwarf2_get_attr_constant_value (const struct attribute *attr, int default_value)
return DW_UNSND (attr);
else
{
+ /* For DW_FORM_data16 see attr_form_is_constant. */
complaint (&symfile_complaints,
_("Attribute value is not a constant (%s)"),
dwarf_form_name (attr->form));
@@ -20694,6 +20709,7 @@ dwarf2_fetch_constant_bytes (sect_offset offset,
case DW_FORM_block4:
case DW_FORM_block:
case DW_FORM_exprloc:
+ case DW_FORM_data16:
result = DW_BLOCK (attr)->data;
*len = DW_BLOCK (attr)->size;
break;
@@ -21602,6 +21618,10 @@ skip_form_bytes (bfd *abfd, const gdb_byte *bytes, const gdb_byte *buffer_end,
bytes += 8;
break;
+ case DW_FORM_data16:
+ bytes += 16;
+ break;
+
case DW_FORM_string:
read_direct_string (abfd, bytes, &bytes_read);
bytes += bytes_read;
@@ -22265,7 +22285,10 @@ attr_form_is_section_offset (const struct attribute *attr)
(lineptr, loclistptr, macptr or rangelistptr). The DWARF spec says
that, if an attribute's can be either a constant or one of the
section offset classes, DW_FORM_data4 and DW_FORM_data8 should be
- taken as section offsets, not constants. */
+ taken as section offsets, not constants.
+
+ DW_FORM_data16 is not considered as dwarf2_get_attr_constant_value
+ cannot handle that. */
static int
attr_form_is_constant (const struct attribute *attr)
new file mode 100644
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2017 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+int
+main ()
+{
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,77 @@
+# Copyright 2017 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if {![dwarf2_support]} {
+ return 0
+}
+
+standard_testfile .c formdata16-dw.S
+
+# We need to know the endianess in order
+# to write some of the debugging info we'd like to generate.
+if [prepare_for_testing "failed to prepare for endianness test" ${testfile} ${srcfile}] {
+ return -1
+}
+
+set endianness "little"
+set test "show endian"
+gdb_test_multiple $test $test {
+ -re "(.* )(big|little)( endian.*)\r\n$gdb_prompt $" {
+ set endianness $expect_out(2,string)
+ pass "endianness"
+ }
+}
+
+set high "0x123456789abcdef0"
+set low "0x0fedcba987654321"
+if { $endianness == "big" } {
+ set pair $high,$low
+} else {
+ set pair $low,$high
+}
+
+# Make some DWARF for the test.
+set asm_file [standard_output_file $srcfile2]
+Dwarf::assemble $asm_file {
+ global pair
+
+ cu { addr_size 4 } {
+ compile_unit {} {
+ declare_labels int_label
+
+ int_label: DW_TAG_base_type {
+ {DW_AT_byte_size 16 DW_FORM_udata}
+ {DW_AT_encoding @DW_ATE_unsigned}
+ {DW_AT_name "__uint128"}
+ }
+
+ DW_TAG_variable {
+ {name xxx}
+ {type :$int_label}
+ {const_value $pair DW_FORM_data16}
+ }
+ }
+ }
+}
+
+if { [prepare_for_testing "failed to prepare" ${testfile} \
+ [list $srcfile $asm_file] {nodebug}] } {
+ return -1
+}
+
+gdb_test "p/x xxx" " = 0x123456789abcdef00fedcba987654321"
@@ -481,6 +481,10 @@ namespace eval Dwarf {
_op .8byte $value
}
+ DW_FORM_data16 {
+ _op .8byte $value
+ }
+
DW_FORM_strp {
variable _strings
variable _cu_offset_size