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import gdb
"""
All of this script relies heavily on Eo internals and will break if they
change. Need to make sure this is always in sync.
"""
ptr_size = int(gdb.parse_and_eval('sizeof(void *)'))
if ptr_size == 4:
# 32 bits
BITS_MID_TABLE_ID = 5
BITS_TABLE_ID = 5
BITS_ENTRY_ID = 12
BITS_GENERATION_COUNTER = 9
REF_TAG_SHIFT = 31
DROPPED_TABLES = 0
DROPPED_ENTRIES = 4
else:
# 64 bits
BITS_MID_TABLE_ID = 11
BITS_TABLE_ID = 11
BITS_ENTRY_ID = 12
BITS_GENERATION_COUNTER = 29
REF_TAG_SHIFT = 63
DROPPED_TABLES = 2
DROPPED_ENTRIES = 3
# /* Shifts macros to manipulate the Eo id */
SHIFT_MID_TABLE_ID = (BITS_TABLE_ID + BITS_ENTRY_ID + BITS_GENERATION_COUNTER)
SHIFT_TABLE_ID = (BITS_ENTRY_ID + BITS_GENERATION_COUNTER)
SHIFT_ENTRY_ID = (BITS_GENERATION_COUNTER)
# /* Maximum ranges */
MAX_MID_TABLE_ID = (1 << BITS_MID_TABLE_ID)
MAX_TABLE_ID = ((1 << BITS_TABLE_ID) - DROPPED_TABLES)
MAX_ENTRY_ID = ((1 << BITS_ENTRY_ID) - DROPPED_ENTRIES)
MAX_GENERATIONS = (1 << BITS_GENERATION_COUNTER)
# /* Masks */
MASK_MID_TABLE_ID = (MAX_MID_TABLE_ID - 1)
MASK_TABLE_ID = ((1 << BITS_TABLE_ID) - 1)
MASK_ENTRY_ID = ((1 << BITS_ENTRY_ID) - 1)
MASK_GENERATIONS = (MAX_GENERATIONS - 1)
MASK_OBJ_TAG = (1 << (REF_TAG_SHIFT))
null_ptr = gdb.parse_and_eval('(_Eo_Object *) 0')
class Eo_resolve(gdb.Function):
def __init__(self):
gdb.Function.__init__(self, 'eo_resolve')
def invoke(self, arg):
obj_id = int(arg)
mid_table_id = (obj_id >> SHIFT_MID_TABLE_ID) & MASK_MID_TABLE_ID
table_id = (obj_id >> SHIFT_TABLE_ID) & MASK_TABLE_ID
entry_id = (obj_id >> SHIFT_ENTRY_ID) & MASK_ENTRY_ID
tag_bit = (obj_id) & MASK_OBJ_TAG
generation = obj_id & MASK_GENERATIONS
if (obj_id == 0) or (tag_bit == 0):
gdb.write('Pointer is NULL or not a valid object.\n')
return null_ptr
entries = gdb.parse_and_eval('_eo_ids_tables[{0}]'.format(mid_table_id))
if int(entries) == 0:
gdb.write('Pointer is not a valid object.\n')
return null_ptr
entry = entries[table_id]['entries'][entry_id]
if (not entry['active']) or (int(entry['generation']) != generation):
gdb.write('Pointer is no longer active.\n')
return null_ptr
return entry['ptr']
Eo_resolve()
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