Ada subscripting of pointer to array with dynamic bounds

Ada subscripting of pointer to array with dynamic bounds

Consider a pointer to an array which dynamic bounds, described in
DWARF as follow:

        <1><25>: Abbrev Number: 4 (DW_TAG_array_type)
           <26>   DW_AT_name        : foo__array_type
        [...]
        <2><3b>: Abbrev Number: 5 (DW_TAG_subrange_type)
           [...]
           <40>   DW_AT_lower_bound : 5 byte block: 97 38 1c 94 4
                  (DW_OP_push_object_address; DW_OP_lit8; DW_OP_minus;
                   DW_OP_deref_size: 4)
           <46>   DW_AT_upper_bound : 5 byte block: 97 34 1c 94 4
                  (DW_OP_push_object_address; DW_OP_lit4; DW_OP_minus;
                   DW_OP_deref_size: 4)

GDB is now able to correctly print the entire array, but not one
element of the array. Eg:

    (gdb) p foo.three_ptr.all
    $1 = (1, 2, 3)
    (gdb) p foo.three_ptr.all(1)
    Cannot access memory at address 0xfffffffff4123a0c

The problem occurs because we are missing a dynamic resolution of
the variable's array type when subscripting the array. What the current
code does is "fix"-ing the array type using the GNAT encodings, but
that operation ignores any of the array's dynamic properties.

This patch fixes the issue by using ada_value_ind to dereference
the array pointer, which takes care of the array type resolution.
It also continues to "fix" arrays described using GNAT encodings,
so backwards compatibility is preserved.

gdb/ChangeLog:

        * ada-lang.c (ada_value_ptr_subscript): Remove parameter "type".
        Adjust function implementation and documentation accordingly.
        (ada_evaluate_subexp) <OP_FUNCALL>: Only assign "type" if
        NOSIDE is EVAL_AVOID_SIDE_EFFECTS.
        Update call to ada_value_ptr_subscript.

gdb/testsuite/ChangeLog:

        * gdb.dwarf2/dynarr-ptr.exp: Add subscripting tests.