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[Ada] Full view of tagged type with ptype

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When evaluating an expression, if it is of a tagged type, GDB reads
the tag in memory and deduces the full view. At parsing time, however,
this operation is done only in the case of OP_VAR_VALUE. ptype does
not go through a full evaluation of expressions so it may return some
odd results:

 (gdb) print c.menu_name
 $1 = 0x0
 (gdb) ptype $
 type = system.strings.string_access
 (gdb) ptype c.menu_name
 type = <void>

This change removes this peculiarity by extending the tag resolution
to UNOP_IND and STRUCTOP_STRUCT. As in the case of OP_VAR_VALUE, this
implies switching from EVAL_AVOID_SIDE_EFFECTS to EVAL_NORMAL when a
tagged type is dereferenced.

gdb/
	* ada-lang.c (ada_evaluate_subexp): Resolve tagged types to
	full view in the case of UNOP_IND and STRUCTOP_STRUCT.

gdb/testsuite/

	* gdb.ada/tagged_access: New testcase.
This commit is contained in:
Jerome Guitton 2014-02-12 12:08:23 +01:00 • committed by Joel Brobecker
parent 7d03f2eb64
commit 5ec18f2b48
7 changed files with 162 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

47
gdb/ada-lang.c
View file

@ -9878,6 +9878,7 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
enum exp_opcode op;
int tem;
int pc;
int preeval_pos;
struct value *arg1 = NULL, *arg2 = NULL, *arg3;
struct type *type;
int nargs, oplen;
@ -10713,6 +10714,7 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
return arg1;
case UNOP_IND:
preeval_pos = *pos;
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
if (noside == EVAL_SKIP)
goto nosideret;
@ -10733,10 +10735,26 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
/* In C you can dereference an array to get the 1st elt. */
|| TYPE_CODE (type) == TYPE_CODE_ARRAY)
{
type = to_static_fixed_type
(ada_aligned_type
(ada_check_typedef (TYPE_TARGET_TYPE (type))));
check_size (type);
/* As mentioned in the OP_VAR_VALUE case, tagged types can
only be determined by inspecting the object's tag.
This means that we need to evaluate completely the
expression in order to get its type. */
if ((TYPE_CODE(type) == TYPE_CODE_REF
|| TYPE_CODE(type) == TYPE_CODE_PTR)
&& ada_is_tagged_type (TYPE_TARGET_TYPE (type), 0))
{
arg1 = evaluate_subexp (NULL_TYPE, exp, &preeval_pos,
EVAL_NORMAL);
type = value_type (ada_value_ind (arg1));
}
else
{
type = to_static_fixed_type
(ada_aligned_type
(ada_check_typedef (TYPE_TARGET_TYPE (type))));
}
check_size (type);
return value_zero (type, lval_memory);
}
else if (TYPE_CODE (type) == TYPE_CODE_INT)
@ -10780,6 +10798,7 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
case STRUCTOP_STRUCT:
tem = longest_to_int (exp->elts[pc + 1].longconst);
(*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
preeval_pos = *pos;
arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
if (noside == EVAL_SKIP)
goto nosideret;
@ -10792,13 +10811,21 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
type = ada_lookup_struct_elt_type (type1,
&exp->elts[pc + 2].string,
1, 1, NULL);
/* If the field is not found, check if it exists in the
extension of this object's type. This means that we
need to evaluate completely the expression. */
if (type == NULL)
/* In this case, we assume that the field COULD exist
in some extension of the type. Return an object of
"type" void, which will match any formal
(see ada_type_match). */
return value_zero (builtin_type (exp->gdbarch)->builtin_void,
lval_memory);
{
arg1 = evaluate_subexp (NULL_TYPE, exp, &preeval_pos,
EVAL_NORMAL);
arg1 = ada_value_struct_elt (arg1,
&exp->elts[pc + 2].string,
0);
arg1 = unwrap_value (arg1);
type = value_type (ada_to_fixed_value (arg1));
}
}
else
type =