Consider the following declarations in Ada...
type Item is range -32 .. 31;
for Item'Size use 6;
type Table is array (Natural range 0 .. 4) of Item;
pragma Pack (Table);
... which declare a packed array whose elements are 6 bits long.
The debugger currently does not notice that the array is packed,
and thus prints values of this type incorrectly. This can be seen
in the "ptype" output:
(gdb) ptype table
type = array (0 .. 4) of foo.item
Normally, the debugger should print:
(gdb) ptype table
type = array (0 .. 4) of foo.item <packed: 6-bit elements>
The debugging information for this array looks like this:
.uleb128 0xf # (DIE (0x15c) DW_TAG_array_type)
.long .LASF9 # DW_AT_name: "pck__table"
.byte 0x6 # DW_AT_bit_stride
.long 0x1a9 # DW_AT_type
.uleb128 0x10 # (DIE (0x16a) DW_TAG_subrange_type)
.long 0x3b # DW_AT_type
.byte 0 # DW_AT_lower_bound
.byte 0x4 # DW_AT_upper_bound
.byte 0 # end of children of DIE 0x15c
The interesting part is the DW_AT_bit_stride attribute, which tells
the size of the array elements is 6 bits, rather than the normal
element type's size.
This patch adds support for this attribute by first creating
gdbtypes.c::create_array_type_with_stride, which is an enhanced
version of create_array_type taking an extra parameter as the stride.
The old create_array_type can then be re-implemented very simply
by calling the new create_array_type_with_stride.
We can then use this new function from dwarf2read, to create
arrays with or without stride.
gdb/ChangeLog:
* gdbtypes.h (create_array_type_with_stride): Add declaration.
* gdbtypes.c (create_array_type_with_stride): New function,
renaming create_array_type, but with an added parameter
called "bit_stride".
(create_array_type): Re-implement using
create_array_type_with_stride.
* dwarf2read.c (read_array_type): Add support for DW_AT_byte_stride
and DW_AT_bit_stride attributes.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/arr-stride.c: New file.
* gdb.dwarf2/arr-stride.exp: New file.
The test, relying purely on generating an assembly file, only
verifies the type description of our array. But I was also
able to verify manually that the debugger print values of these
types correctly as well (which was not the case prior to this
patch).
+2014-02-26 Joel Brobecker <brobecker@adacore.com>
+
+ * gdbtypes.h (create_array_type_with_stride): Add declaration.
+ * gdbtypes.c (create_array_type_with_stride): New function,
+ renaming create_array_type, but with an added parameter
+ called "bit_stride".
+ (create_array_type): Re-implement using
+ create_array_type_with_stride.
+ * dwarf2read.c (read_array_type): Add support for DW_AT_byte_stride
+ and DW_AT_bit_stride attributes.
+
2014-02-26 Pedro Alves <palves@redhat.com>
* breakpoint.c (bpstat_check_breakpoint_conditions): Handle
int ndim = 0;
struct cleanup *back_to;
const char *name;
+ unsigned int bit_stride = 0;
element_type = die_type (die, cu);
if (type)
return type;
+ attr = dwarf2_attr (die, DW_AT_byte_stride, cu);
+ if (attr != NULL)
+ bit_stride = DW_UNSND (attr) * 8;
+
+ attr = dwarf2_attr (die, DW_AT_bit_stride, cu);
+ if (attr != NULL)
+ bit_stride = DW_UNSND (attr);
+
/* Irix 6.2 native cc creates array types without children for
arrays with unspecified length. */
if (die->child == NULL)
{
index_type = objfile_type (objfile)->builtin_int;
range_type = create_range_type (NULL, index_type, 0, -1);
- type = create_array_type (NULL, element_type, range_type);
+ type = create_array_type_with_stride (NULL, element_type, range_type,
+ bit_stride);
return set_die_type (die, type, cu);
}
int i = 0;
while (i < ndim)
- type = create_array_type (NULL, type, range_types[i++]);
+ type = create_array_type_with_stride (NULL, type, range_types[i++],
+ bit_stride);
}
else
{
while (ndim-- > 0)
- type = create_array_type (NULL, type, range_types[ndim]);
+ type = create_array_type_with_stride (NULL, type, range_types[ndim],
+ bit_stride);
}
/* Understand Dwarf2 support for vector types (like they occur on
Elements will be of type ELEMENT_TYPE, the indices will be of type
RANGE_TYPE.
+ If BIT_STRIDE is not zero, build a packed array type whose element
+ size is BIT_STRIDE. Otherwise, ignore this parameter.
+
FIXME: Maybe we should check the TYPE_CODE of RESULT_TYPE to make
sure it is TYPE_CODE_UNDEF before we bash it into an array
type? */
struct type *
-create_array_type (struct type *result_type,
- struct type *element_type,
- struct type *range_type)
+create_array_type_with_stride (struct type *result_type,
+ struct type *element_type,
+ struct type *range_type,
+ unsigned int bit_stride)
{
LONGEST low_bound, high_bound;
In such cases, the array length should be zero. */
if (high_bound < low_bound)
TYPE_LENGTH (result_type) = 0;
+ else if (bit_stride > 0)
+ TYPE_LENGTH (result_type) =
+ (bit_stride * (high_bound - low_bound + 1) + 7) / 8;
else
TYPE_LENGTH (result_type) =
TYPE_LENGTH (element_type) * (high_bound - low_bound + 1);
(struct field *) TYPE_ZALLOC (result_type, sizeof (struct field));
TYPE_INDEX_TYPE (result_type) = range_type;
TYPE_VPTR_FIELDNO (result_type) = -1;
+ if (bit_stride > 0)
+ TYPE_FIELD_BITSIZE (result_type, 0) = bit_stride;
/* TYPE_FLAG_TARGET_STUB will take care of zero length arrays. */
if (TYPE_LENGTH (result_type) == 0)
return result_type;
}
+/* Same as create_array_type_with_stride but with no bit_stride
+ (BIT_STRIDE = 0), thus building an unpacked array. */
+
+struct type *
+create_array_type (struct type *result_type,
+ struct type *element_type,
+ struct type *range_type)
+{
+ return create_array_type_with_stride (result_type, element_type,
+ range_type, 0);
+}
+
struct type *
lookup_array_range_type (struct type *element_type,
LONGEST low_bound, LONGEST high_bound)
extern struct type *create_range_type (struct type *, struct type *, LONGEST,
LONGEST);
+extern struct type *create_array_type_with_stride
+ (struct type *, struct type *, struct type *, unsigned int);
+
extern struct type *create_array_type (struct type *, struct type *,
struct type *);
+
extern struct type *lookup_array_range_type (struct type *, LONGEST, LONGEST);
extern struct type *create_string_type (struct type *, struct type *,
+2014-02-26 Joel Brobecker <brobecker@adacore.com>
+
+ * gdb.dwarf2/arr-stride.c: New file.
+ * gdb.dwarf2/arr-stride.exp: New file.
+
2014-02-26 Pedro Alves <palves@redhat.com>
* gdb.ada/tasks.exp: Set a task-specific breakpoint at break_me
--- /dev/null
+/* Copyright 2014 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 (void)
+{
+ return 0;
+}
--- /dev/null
+# Copyright 2014 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 arr-stride.c arr-stride-dw.S
+
+# Make some DWARF for the test.
+set asm_file [standard_output_file $srcfile2]
+Dwarf::assemble $asm_file {
+ cu {} {
+ DW_TAG_compile_unit {
+ {DW_AT_language @DW_LANG_Ada95}
+ {DW_AT_name foo.adb}
+ {DW_AT_comp_dir /tmp}
+ } {
+ declare_labels integer_label array_elt_label array_label \
+ big_array_label
+
+ integer_label: DW_TAG_base_type {
+ {DW_AT_byte_size 4 DW_FORM_sdata}
+ {DW_AT_encoding @DW_ATE_signed}
+ {DW_AT_name integer}
+ }
+
+ array_elt_label: DW_TAG_subrange_type {
+ {DW_AT_lower_bound 0xe0 DW_FORM_data1}
+ {DW_AT_upper_bound 0x1f DW_FORM_data1}
+ {DW_AT_name pck__item}
+ {DW_AT_type :$integer_label}
+ }
+
+ DW_TAG_typedef {
+ {DW_AT_name pck__table}
+ {DW_AT_type :$array_label}
+ }
+
+ array_label: DW_TAG_array_type {
+ {DW_AT_name pck__table}
+ {DW_AT_bit_stride 6 DW_FORM_data1}
+ {DW_AT_type :$array_elt_label}
+ } {
+ DW_TAG_subrange_type {
+ {DW_AT_type :$integer_label}
+ {DW_AT_lower_bound 0 DW_FORM_data1}
+ {DW_AT_upper_bound 4 DW_FORM_data1}
+ }
+ }
+
+ DW_TAG_typedef {
+ {DW_AT_name pck__big_table}
+ {DW_AT_type :$big_array_label}
+ }
+
+ big_array_label: DW_TAG_array_type {
+ {DW_AT_name pck__big_table}
+ {DW_AT_byte_stride 1 DW_FORM_data1}
+ {DW_AT_type :$array_elt_label}
+ } {
+ DW_TAG_subrange_type {
+ {DW_AT_type :$integer_label}
+ {DW_AT_lower_bound 0 DW_FORM_data1}
+ {DW_AT_upper_bound 4 DW_FORM_data1}
+ }
+ }
+ }
+ }
+}
+
+if {[gdb_compile ${srcdir}/${subdir}/${srcfile} ${binfile}1.o \
+ object {nodebug}] != ""} {
+ return -1
+}
+
+if {[gdb_compile $asm_file ${binfile}2.o object {nodebug}] != ""} {
+ return -1
+}
+
+if {[gdb_compile [list ${binfile}1.o ${binfile}2.o] \
+ "${binfile}" executable {}] != ""} {
+ return -1
+}
+
+clean_restart ${testfile}
+
+gdb_test_no_output "set language ada"
+
+gdb_test "ptype pck.table" \
+ "type = array \\(0 \\.\\. 4\\) of pck\\.item <packed: 6-bit elements>"
+
+gdb_test "ptype pck.big_table" \
+ "type = array \\(0 \\.\\. 4\\) of pck\\.item <packed: 8-bit elements>"
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