DWARF-5: DW_FORM_data16

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*.

gdb/ChangeLog
2017-02-20  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
2017-02-20  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.
This commit is contained in:
Jan Kratochvil 2017-02-20 20:53:22 +01:00
parent 0af92d6069
commit 0224619f60
6 changed files with 140 additions and 1 deletions

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@ -1,3 +1,10 @@
2017-02-20 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.
2017-02-20 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2read.c (read_file_scope): Rename DW_MACRO_GNU_*.

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@ -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;
@ -16554,6 +16557,13 @@ 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;
@ -19297,6 +19307,7 @@ 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,
@ -20251,6 +20262,9 @@ 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);
@ -20412,6 +20426,7 @@ 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));
@ -20695,6 +20710,7 @@ 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;
@ -21603,6 +21619,10 @@ 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;
@ -22266,7 +22286,10 @@ 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)

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@ -1,3 +1,9 @@
2017-02-20 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.
2017-02-20 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.arch/amd64-entry-value-param-dwarf5.S: New file.

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@ -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;
}

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@ -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"

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@ -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