[commit/Ada,2/2] slices of arrays with dynamic strides
Commit Message
Hello,
This is a patch which fixes an isses with array slices in Ada
when the array has a dynamic stride. It depends on the patch
adding support for DW_AT_byte_stride, so I will push after
the first one gets approved.
Consider the following Ada code:
procedure Nested (L, U : Integer) is
subtype Small_Type is Integer range L .. U;
type Record_Type (I : Small_Type := L) is record
S : String (1 .. I);
end record;
type Array_Type is array (Integer range <>) of Record_Type;
A1 : Array_Type :=
(1 => (I => 0, S => <>),
2 => (I => 1, S => "A"),
3 => (I => 2, S => "AB"));
procedure Discard (R : Record_Type) is
begin
null;
end Discard;
begin
Discard (A1 (1)); -- STOP
end;
Trying to print a slice of that array currently yields:
(gdb) p a1(1..3)
$1 = ((i => 0, s => ""), (i => 0, s => ""), (i => 0, s => ""))
We expected instead:
(gdb) p a1(1..3)
$1 = ((i => 0, s => ""), (i => 1, s => "A"), (i => 2, s => "AB"))
This is because the functions we use in ada-lang.c to create the type
of the array slice (ada_value_slice and ada_value_slice_from_ptr) was
not taking into account the stride of the array. This patch fixes this.
gdb/ChangeLog:
* ada-lang.c (ada_value_slice_from_ptr): Take array stride into
account when creating the array type of the slice.
(ada_value_slice): Likewise.
gdb/testsuite/ChangeLog:
* gdb.ada/dyn_stride.exp: Add slice test.
Note that, with the current use of ada_value_slice, the enhancement
to handle dynamic array strides seems unnecessary, because I do not
see how an array with a dynamic stride can be referenced by either
by reference or pointer. Since references are coerced to array pointers,
in both cases, the slice is performed by ada_value_slice_from_ptr.
But ada_value_slice is enhanced nonetheless, in the spirit of making
the code more robust, in case we missed something, and also as similar
as possible with its from_ptr counterpart.
tested on x86_64-linux.
Thanks,
Comments
> gdb/ChangeLog:
>
> * ada-lang.c (ada_value_slice_from_ptr): Take array stride into
> account when creating the array type of the slice.
> (ada_value_slice): Likewise.
>
> gdb/testsuite/ChangeLog:
>
> * gdb.ada/dyn_stride.exp: Add slice test.
Pushed as well :).
@@ -2910,8 +2910,10 @@ ada_value_slice_from_ptr (struct value *array_ptr, struct type *type,
struct type *base_index_type = TYPE_TARGET_TYPE (TYPE_INDEX_TYPE (type0));
struct type *index_type
= create_static_range_type (NULL, base_index_type, low, high);
- struct type *slice_type =
- create_array_type (NULL, TYPE_TARGET_TYPE (type0), index_type);
+ struct type *slice_type = create_array_type_with_stride
+ (NULL, TYPE_TARGET_TYPE (type0), index_type,
+ get_dyn_prop (DYN_PROP_BYTE_STRIDE, type0),
+ TYPE_FIELD_BITSIZE (type0, 0));
int base_low = ada_discrete_type_low_bound (TYPE_INDEX_TYPE (type0));
LONGEST base_low_pos, low_pos;
CORE_ADDR base;
@@ -2938,8 +2940,10 @@ ada_value_slice (struct value *array, int low, int high)
struct type *base_index_type = TYPE_TARGET_TYPE (TYPE_INDEX_TYPE (type));
struct type *index_type
= create_static_range_type (NULL, TYPE_INDEX_TYPE (type), low, high);
- struct type *slice_type =
- create_array_type (NULL, TYPE_TARGET_TYPE (type), index_type);
+ struct type *slice_type = create_array_type_with_stride
+ (NULL, TYPE_TARGET_TYPE (type), index_type,
+ get_dyn_prop (DYN_PROP_BYTE_STRIDE, type),
+ TYPE_FIELD_BITSIZE (type, 0));
LONGEST low_pos, high_pos;
if (!discrete_position (base_index_type, low, &low_pos)
@@ -36,3 +36,6 @@ gdb_test "print A1(2)" \
gdb_test "print A1(3)" \
"\\(i => 2, s => \"AB\"\\)"
+
+gdb_test "print A1(1..3)" \
+ "\\(\\(i => 0, s => \"\"\\), \\(i => 1, s => \"A\"\\), \\(i => 2, s => \"AB\"\\)\\)"