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Change allocation of type-copying hash table

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When an objfile is destroyed, types that are still in use and
allocated on that objfile are copied.  A temporary hash map is created
during this process, and it is allocated on the destroyed objfile's
obstack -- which normally is fine, as that is going to be destroyed
shortly anyway.

However, this approach requires that the objfile be passed to registry
destruction, and this won't be possible in the rewritten registry.
This patch changes the copied type hash table to simply use the heap
instead.  It also removes the 'objfile' parameter from
copy_type_recursive, to make this all more clear.

This patch also fixes an apparent bug in copy_type_recursive.
Previously it was copying the dynamic property list to the dying
objfile's obstack:

-      = copy_dynamic_prop_list (&objfile->objfile_obstack,

However I think this is incorrect -- that obstack is about to be
destroyed.
This commit is contained in:
Tom Tromey 2022-05-24 15:17:19 -06:00
parent b382c16682
commit bde539c2f9
6 changed files with 27 additions and 42 deletions
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40
gdb/gdbtypes.c
View file

@ -5562,7 +5562,7 @@ recursive_dump_type (struct type *type, int spaces)
/* Trivial helpers for the libiberty hash table, for mapping one
type to another. */
struct type_pair : public allocate_on_obstack
struct type_pair
{
type_pair (struct type *old_, struct type *newobj_)
: old (old_), newobj (newobj_)
@ -5589,22 +5589,20 @@ type_pair_eq (const void *item_lhs, const void *item_rhs)
}
/* Allocate the hash table used by copy_type_recursive to walk
types without duplicates. We use OBJFILE's obstack, because
OBJFILE is about to be deleted. */
types without duplicates. */
htab_up
create_copied_types_hash (struct objfile *objfile)
create_copied_types_hash ()
{
return htab_up (htab_create_alloc_ex (1, type_pair_hash, type_pair_eq,
NULL, &objfile->objfile_obstack,
hashtab_obstack_allocate,
dummy_obstack_deallocate));
return htab_up (htab_create_alloc (1, type_pair_hash, type_pair_eq,
htab_delete_entry<type_pair>,
xcalloc, xfree));
}
/* Recursively copy (deep copy) a dynamic attribute list of a type. */
static struct dynamic_prop_list *
copy_dynamic_prop_list (struct obstack *objfile_obstack,
copy_dynamic_prop_list (struct obstack *storage,
struct dynamic_prop_list *list)
{
struct dynamic_prop_list *copy = list;
@ -5615,7 +5613,7 @@ copy_dynamic_prop_list (struct obstack *objfile_obstack,
struct dynamic_prop_list *node_copy;
node_copy = ((struct dynamic_prop_list *)
obstack_copy (objfile_obstack, *node_ptr,
obstack_copy (storage, *node_ptr,
sizeof (struct dynamic_prop_list)));
node_copy->prop = (*node_ptr)->prop;
*node_ptr = node_copy;
@ -5632,9 +5630,7 @@ copy_dynamic_prop_list (struct obstack *objfile_obstack,
it is not associated with OBJFILE. */
struct type *
copy_type_recursive (struct objfile *objfile,
struct type *type,
htab_t copied_types)
copy_type_recursive (struct type *type, htab_t copied_types)
{
void **slot;
struct type *new_type;
@ -5642,10 +5638,6 @@ copy_type_recursive (struct objfile *objfile,
if (!type->is_objfile_owned ())
return type;
/* This type shouldn't be pointing to any types in other objfiles;
if it did, the type might disappear unexpectedly. */
gdb_assert (type->objfile_owner () == objfile);
struct type_pair pair (type, nullptr);
slot = htab_find_slot (copied_types, &pair, INSERT);
@ -5656,8 +5648,7 @@ copy_type_recursive (struct objfile *objfile,
/* We must add the new type to the hash table immediately, in case
we encounter this type again during a recursive call below. */
struct type_pair *stored
= new (&objfile->objfile_obstack) struct type_pair (type, new_type);
struct type_pair *stored = new type_pair (type, new_type);
*slot = stored;
@ -5690,8 +5681,7 @@ copy_type_recursive (struct objfile *objfile,
TYPE_FIELD_BITSIZE (new_type, i) = TYPE_FIELD_BITSIZE (type, i);
if (type->field (i).type ())
new_type->field (i).set_type
(copy_type_recursive (objfile, type->field (i).type (),
copied_types));
(copy_type_recursive (type->field (i).type (), copied_types));
if (type->field (i).name ())
new_type->field (i).set_name (xstrdup (type->field (i).name ()));
@ -5736,16 +5726,14 @@ copy_type_recursive (struct objfile *objfile,
if (type->main_type->dyn_prop_list != NULL)
new_type->main_type->dyn_prop_list
= copy_dynamic_prop_list (&objfile->objfile_obstack,
= copy_dynamic_prop_list (gdbarch_obstack (new_type->arch_owner ()),
type->main_type->dyn_prop_list);
/* Copy pointers to other types. */
if (TYPE_TARGET_TYPE (type))
TYPE_TARGET_TYPE (new_type) =
copy_type_recursive (objfile,
TYPE_TARGET_TYPE (type),
copied_types);
copy_type_recursive (TYPE_TARGET_TYPE (type), copied_types);
/* Maybe copy the type_specific bits.
@ -5774,7 +5762,7 @@ copy_type_recursive (struct objfile *objfile,
break;
case TYPE_SPECIFIC_SELF_TYPE:
set_type_self_type (new_type,
copy_type_recursive (objfile, TYPE_SELF_TYPE (type),
copy_type_recursive (TYPE_SELF_TYPE (type),
copied_types));
break;
case TYPE_SPECIFIC_FIXED_POINT: