This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
Re: [patch] Fix duplicate types for single DIE
On Fri, 21 May 2010 01:31:31 +0200, Joel Brobecker wrote:
> > Tom Tromey may not agree with new internal_error as expressed in
[...]
> This is a situation where we can recover without much hassle by just
> allocating a new slot, so I'd just emit a complaint, and allow the
> user to continue debugging.
OK, that looks better, changed.
> There's something I can seem to be able to understand: Why does
> set_descriptive_type need to be called after set_die_type? I mean,
> from a conceptual point of view, it sort of makes sense. But I can't
> see how in practice changing the call order makes any difference...
Created there a new comment at set_die_type for some general rules of reading
in DIEs/TYPEs and their inter-referencing. I see it was missing there.
Therefore I find it more simple to just follow some paradigm than to think
whether it is safe to violate it in that specific case. Moreover I was not
sure about this Ada descriptive types myself (which you have made clear now).
Also the order does not matter IMO, code efficiency is the same.
I can remove these descriptive_type changes if you think so.
Thanks,
Jan
2010-05-21 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2read.c (read_structure_type): Move set_descriptive_type after
set_die_type.
(read_array_type): Remove type initialization. Recheck get_die_type
after initial die_type. Move set_die_type before set_descriptive_type.
(read_set_type): New variable domain_type. Recheck get_die_type after
initial die_type. Move attr initialization later.
(read_tag_pointer_type, read_tag_reference_type): New variable
target_type. Recheck get_die_type after initial die_type.
(read_tag_ptr_to_member_type): Recheck get_die_type after initial
die_type and die_containing_type.
(read_tag_const_type, read_tag_volatile_type, read_subroutine_type):
Recheck get_die_type after initial die_type.
(read_subrange_type): Recheck get_die_type after initial die_type.
Move set_die_type before set_descriptive_type.
(set_die_type): Extend the function comment. Call complaint if DIE has
some type already set.
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -5125,13 +5125,14 @@ read_structure_type (struct die_info *die, struct dwarf2_cu *cu)
on incomplete types. */
TYPE_STUB (type) = 1;
- set_descriptive_type (type, die, cu);
-
/* We need to add the type field to the die immediately so we don't
infinitely recurse when dealing with pointers to the structure
type within the structure itself. */
set_die_type (die, type, cu);
+ /* set_die_type should be already done. */
+ set_descriptive_type (type, die, cu);
+
if (die->child != NULL && ! die_is_declaration (die, cu))
{
struct field_info fi;
@@ -5420,7 +5421,7 @@ read_array_type (struct die_info *die, struct dwarf2_cu *cu)
{
struct objfile *objfile = cu->objfile;
struct die_info *child_die;
- struct type *type = NULL;
+ struct type *type;
struct type *element_type, *range_type, *index_type;
struct type **range_types = NULL;
struct attribute *attr;
@@ -5430,6 +5431,11 @@ read_array_type (struct die_info *die, struct dwarf2_cu *cu)
element_type = die_type (die, cu);
+ /* The die_type call above may have already set the type for this DIE. */
+ type = get_die_type (die, cu);
+ if (type)
+ return type;
+
/* Irix 6.2 native cc creates array types without children for
arrays with unspecified length. */
if (die->child == NULL)
@@ -5498,12 +5504,15 @@ read_array_type (struct die_info *die, struct dwarf2_cu *cu)
if (name)
TYPE_NAME (type) = name;
+ /* Install the type in the die. */
+ set_die_type (die, type, cu);
+
+ /* set_die_type should be already done. */
set_descriptive_type (type, die, cu);
do_cleanups (back_to);
- /* Install the type in the die. */
- return set_die_type (die, type, cu);
+ return type;
}
static enum dwarf_array_dim_ordering
@@ -5546,11 +5555,22 @@ read_array_order (struct die_info *die, struct dwarf2_cu *cu)
static struct type *
read_set_type (struct die_info *die, struct dwarf2_cu *cu)
{
- struct type *set_type = create_set_type (NULL, die_type (die, cu));
- struct attribute *attr = dwarf2_attr (die, DW_AT_byte_size, cu);
+ struct type *domain_type, *set_type;
+ struct attribute *attr;
+ domain_type = die_type (die, cu);
+
+ /* The die_type call above may have already set the type for this DIE. */
+ set_type = get_die_type (die, cu);
+ if (set_type)
+ return set_type;
+
+ set_type = create_set_type (NULL, domain_type);
+
+ attr = dwarf2_attr (die, DW_AT_byte_size, cu);
if (attr)
TYPE_LENGTH (set_type) = DW_UNSND (attr);
+
return set_die_type (die, set_type, cu);
}
@@ -5749,8 +5769,16 @@ read_tag_pointer_type (struct die_info *die, struct dwarf2_cu *cu)
struct attribute *attr_byte_size;
struct attribute *attr_address_class;
int byte_size, addr_class;
+ struct type *target_type;
+
+ target_type = die_type (die, cu);
+
+ /* The die_type call above may have already set the type for this DIE. */
+ type = get_die_type (die, cu);
+ if (type)
+ return type;
- type = lookup_pointer_type (die_type (die, cu));
+ type = lookup_pointer_type (target_type);
attr_byte_size = dwarf2_attr (die, DW_AT_byte_size, cu);
if (attr_byte_size)
@@ -5806,6 +5834,11 @@ read_tag_ptr_to_member_type (struct die_info *die, struct dwarf2_cu *cu)
to_type = die_type (die, cu);
domain = die_containing_type (die, cu);
+ /* The calls above may have already set the type for this DIE. */
+ type = get_die_type (die, cu);
+ if (type)
+ return type;
+
if (TYPE_CODE (check_typedef (to_type)) == TYPE_CODE_METHOD)
type = lookup_methodptr_type (to_type);
else
@@ -5821,10 +5854,17 @@ static struct type *
read_tag_reference_type (struct die_info *die, struct dwarf2_cu *cu)
{
struct comp_unit_head *cu_header = &cu->header;
- struct type *type;
+ struct type *type, *target_type;
struct attribute *attr;
- type = lookup_reference_type (die_type (die, cu));
+ target_type = die_type (die, cu);
+
+ /* The die_type call above may have already set the type for this DIE. */
+ type = get_die_type (die, cu);
+ if (type)
+ return type;
+
+ type = lookup_reference_type (target_type);
attr = dwarf2_attr (die, DW_AT_byte_size, cu);
if (attr)
{
@@ -5843,6 +5883,12 @@ read_tag_const_type (struct die_info *die, struct dwarf2_cu *cu)
struct type *base_type, *cv_type;
base_type = die_type (die, cu);
+
+ /* The die_type call above may have already set the type for this DIE. */
+ cv_type = get_die_type (die, cu);
+ if (cv_type)
+ return cv_type;
+
cv_type = make_cv_type (1, TYPE_VOLATILE (base_type), base_type, 0);
return set_die_type (die, cv_type, cu);
}
@@ -5853,6 +5899,12 @@ read_tag_volatile_type (struct die_info *die, struct dwarf2_cu *cu)
struct type *base_type, *cv_type;
base_type = die_type (die, cu);
+
+ /* The die_type call above may have already set the type for this DIE. */
+ cv_type = get_die_type (die, cu);
+ if (cv_type)
+ return cv_type;
+
cv_type = make_cv_type (TYPE_CONST (base_type), 1, base_type, 0);
return set_die_type (die, cv_type, cu);
}
@@ -5917,6 +5969,12 @@ read_subroutine_type (struct die_info *die, struct dwarf2_cu *cu)
struct attribute *attr;
type = die_type (die, cu);
+
+ /* The die_type call above may have already set the type for this DIE. */
+ ftype = get_die_type (die, cu);
+ if (ftype)
+ return ftype;
+
ftype = lookup_function_type (type);
/* All functions in C++, Pascal and Java have prototypes. */
@@ -6129,6 +6187,12 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
LONGEST negative_mask;
base_type = die_type (die, cu);
+
+ /* The die_type call above may have already set the type for this DIE. */
+ range_type = get_die_type (die, cu);
+ if (range_type)
+ return range_type;
+
if (TYPE_CODE (base_type) == TYPE_CODE_VOID)
{
complaint (&symfile_complaints,
@@ -6196,9 +6260,12 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
if (attr)
TYPE_LENGTH (range_type) = DW_UNSND (attr);
+ set_die_type (die, range_type, cu);
+
+ /* set_die_type should be already done. */
set_descriptive_type (range_type, die, cu);
- return set_die_type (die, range_type, cu);
+ return range_type;
}
static struct type *
@@ -11984,7 +12051,22 @@ offset_and_type_eq (const void *item_lhs, const void *item_rhs)
}
/* Set the type associated with DIE to TYPE. Save it in CU's hash
- table if necessary. For convenience, return TYPE. */
+ table if necessary. For convenience, return TYPE.
+
+ The DIEs reading must have careful ordering to:
+ * Not cause infite loops trying to read in DIEs as a prerequisite for
+ reading current DIE.
+ * Not trying to dereference contents of still incompletely read in types
+ while reading in other DIEs.
+ * Enable referencing still incompletely read in types just by a pointer to
+ the type without accessing its fields.
+
+ Therefore caller should follow these rules:
+ * Try to fetch any prerequisite types we may need to build this DIE type
+ before building the type and calling set_die_type.
+ * After building typer call set_die_type for current DIE as soon as
+ possible before fetching more types to complete the current type.
+ * Make the type as complete as possible before fetching more types. */
static struct type *
set_die_type (struct die_info *die, struct type *type, struct dwarf2_cu *cu)
@@ -12022,6 +12104,10 @@ set_die_type (struct die_info *die, struct type *type, struct dwarf2_cu *cu)
ofs.type = type;
slot = (struct dwarf2_offset_and_type **)
htab_find_slot_with_hash (cu->type_hash, &ofs, ofs.offset, INSERT);
+ if (*slot)
+ complaint (&symfile_complaints,
+ _("A problem internal to GDB: DIE 0x%x has type already set"),
+ die->offset);
*slot = obstack_alloc (&cu->objfile->objfile_obstack, sizeof (**slot));
**slot = ofs;
return type;