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| author | Joel Brobecker <brobecker@adacore.com> | 2014-01-29 17:39:56 +0400 |
|---|---|---|
| committer | Joel Brobecker <brobecker@adacore.com> | 2014-02-26 06:32:39 -0800 |
| commit | dc53a7adb516adbf2f646a078a1140b1044a39f5 (patch) | |
| tree | 265682442b18ec0711c4957a931474de426beb9b /gdb/ChangeLog | |
| parent | 12ab52e9772a9170018feb44de3ef217e051cc60 (diff) | |
| download | gdb-dc53a7adb516adbf2f646a078a1140b1044a39f5.zip gdb-dc53a7adb516adbf2f646a078a1140b1044a39f5.tar.gz gdb-dc53a7adb516adbf2f646a078a1140b1044a39f5.tar.bz2 | |
DWARF: Add array DW_AT_bit_stride and DW_AT_byte_stride support
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).
Diffstat (limited to 'gdb/ChangeLog')
| -rw-r--r-- | gdb/ChangeLog | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3a02a49..a4377a9 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,14 @@ +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 |