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Ada subscripting of pointer to array with dynamic bounds

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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.
This commit is contained in:
Joel Brobecker 2014-08-29 19:50:03 +02:00
parent 7828a5f5fa
commit deede10c77
4 changed files with 125 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
gdb/ChangeLog
View File

@ -1,3 +1,11 @@
2014-09-10 Joel Brobecker <brobecker@adacore.com>
* 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.
2014-09-10 Joel Brobecker <brobecker@adacore.com>
* ada-valprint.c (ada_value_print): Use VAL's enclosing type

17
gdb/ada-lang.c
View File

@ -2715,15 +2715,16 @@ ada_value_subscript (struct value *arr, int arity, struct value **ind)
return elt;
}
/* Assuming ARR is a pointer to a standard GDB array of type TYPE, the
value of the element of *ARR at the ARITY indices given in
IND. Does not read the entire array into memory. */
/* Assuming ARR is a pointer to a GDB array, the value of the element
of *ARR at the ARITY indices given in IND.
Does not read the entire array into memory. */
static struct value *
ada_value_ptr_subscript (struct value *arr, struct type *type, int arity,
struct value **ind)
ada_value_ptr_subscript (struct value *arr, int arity, struct value **ind)
{
int k;
struct type *type
= check_typedef (value_enclosing_type (ada_value_ind (arr)));
for (k = 0; k < arity; k += 1)
{
@ -10323,9 +10324,9 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
(ada_coerce_to_simple_array (argvec[0]),
nargs, argvec + 1));
case TYPE_CODE_PTR: /* Pointer to array */
type = to_fixed_array_type (TYPE_TARGET_TYPE (type), NULL, 1);
if (noside == EVAL_AVOID_SIDE_EFFECTS)
{
type = to_fixed_array_type (TYPE_TARGET_TYPE (type), NULL, 1);
type = ada_array_element_type (type, nargs);
if (type == NULL)
error (_("element type of array unknown"));
@ -10333,8 +10334,8 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
return value_zero (ada_aligned_type (type), lval_memory);
}
return
unwrap_value (ada_value_ptr_subscript (argvec[0], type,
nargs, argvec + 1));
unwrap_value (ada_value_ptr_subscript (argvec[0],
nargs, argvec + 1));
default:
error (_("Attempt to index or call something other than an "

4
gdb/testsuite/ChangeLog
View File

@ -1,3 +1,7 @@
2014-09-10 Joel Brobecker <brobecker@adacore.com>
* gdb.dwarf2/dynarr-ptr.exp: Add subscripting tests.
2014-09-10 Joel Brobecker <brobecker@adacore.com>
* gdb.dwarf2/dynarr-ptr.c: New file.

104
gdb/testsuite/gdb.dwarf2/dynarr-ptr.exp
View File

@ -137,17 +137,121 @@ gdb_test_no_output "set language ada"
gdb_test "print foo.three_ptr.all" \
" = \\(1, 2, 3\\)"
gdb_test "print foo.three_ptr.all(1)" \
" = 1"
gdb_test "print foo.three_ptr.all(2)" \
" = 2"
gdb_test "print foo.three_ptr.all(3)" \
" = 3"
# foo.three_ptr
gdb_test "print foo.three_ptr(1)" \
" = 1"
gdb_test "print foo.three_ptr(2)" \
" = 2"
gdb_test "print foo.three_ptr(3)" \
" = 3"
# foo.three_ptr_tdef.all
gdb_test "print foo.three_ptr_tdef.all" \
" = \\(1, 2, 3\\)"
gdb_test "print foo.three_ptr_tdef.all(1)" \
" = 1"
gdb_test "print foo.three_ptr_tdef.all(2)" \
" = 2"
gdb_test "print foo.three_ptr_tdef.all(3)" \
" = 3"
# foo.three_ptr_tdef
gdb_test "print foo.three_ptr_tdef(1)" \
" = 1"
gdb_test "print foo.three_ptr_tdef(2)" \
" = 2"
gdb_test "print foo.three_ptr_tdef(3)" \
" = 3"
# foo.five_ptr.all
gdb_test "print foo.five_ptr.all" \
" = \\(2 => 5, 8, 13, 21, 34\\)"
gdb_test "print foo.five_ptr.all(2)" \
" = 5"
gdb_test "print foo.five_ptr.all(3)" \
" = 8"
gdb_test "print foo.five_ptr.all(4)" \
" = 13"
gdb_test "print foo.five_ptr.all(5)" \
" = 21"
gdb_test "print foo.five_ptr.all(6)" \
" = 34"
# foo.five_ptr
gdb_test "print foo.five_ptr(2)" \
" = 5"
gdb_test "print foo.five_ptr(3)" \
" = 8"
gdb_test "print foo.five_ptr(4)" \
" = 13"
gdb_test "print foo.five_ptr(5)" \
" = 21"
gdb_test "print foo.five_ptr(6)" \
" = 34"
# foo.five_ptr_tdef.all
gdb_test "print foo.five_ptr_tdef.all" \
" = \\(2 => 5, 8, 13, 21, 34\\)"
gdb_test "print foo.five_ptr_tdef.all(2)" \
" = 5"
gdb_test "print foo.five_ptr_tdef.all(3)" \
" = 8"
gdb_test "print foo.five_ptr_tdef.all(4)" \
" = 13"
gdb_test "print foo.five_ptr_tdef.all(5)" \
" = 21"
gdb_test "print foo.five_ptr_tdef.all(6)" \
" = 34"
# foo.five_ptr_tdef
gdb_test "print foo.five_ptr_tdef(2)" \
" = 5"
gdb_test "print foo.five_ptr_tdef(3)" \
" = 8"
gdb_test "print foo.five_ptr_tdef(4)" \
" = 13"
gdb_test "print foo.five_ptr_tdef(5)" \
" = 21"
gdb_test "print foo.five_ptr_tdef(6)" \
" = 34"