def _patch_var_dels(self,
internal_dead_map,
escaping_dead_map,
extend_lifetimes=False):
"""
Insert delete in each block
"""
for offset, ir_block in self.func_ir.blocks.items():
# for each internal var, insert delete after the last use
internal_dead_set = internal_dead_map[offset].copy()
delete_pts = []
# for each statement in reverse order
for stmt in reversed(ir_block.body[:-1]):
# internal vars that are used here
live_set = set(v.name for v in stmt.list_vars())
dead_set = live_set & internal_dead_set
for T, def_func in ir_extension_insert_dels.items():
if isinstance(stmt, T):
done_dels = def_func(stmt, dead_set)
dead_set -= done_dels
internal_dead_set -= done_dels
# used here but not afterwards
delete_pts.append((stmt, dead_set))
internal_dead_set -= dead_set
# rewrite body and insert dels
body = []
lastloc = ir_block.loc
del_store = []
for stmt, delete_set in reversed(delete_pts):
# If using extended lifetimes then the Dels are all put at the
# block end just ahead of the terminator, so associate their
# location with the terminator.
if extend_lifetimes:
lastloc = ir_block.body[-1].loc
else:
lastloc = stmt.loc
# Ignore dels (assuming no user inserted deletes)
if not isinstance(stmt, ir.Del):
body.append(stmt)
# note: the reverse sort is not necessary for correctness
# it is just to minimize changes to test for now
for var_name in sorted(delete_set, reverse=True):
delnode = ir.Del(var_name, loc=lastloc)
if extend_lifetimes:
del_store.append(delnode)
else:
body.append(delnode)
if extend_lifetimes:
body.extend(del_store)
body.append(ir_block.body[-1]) # terminator
ir_block.body = body
# vars to delete at the start
escape_dead_set = escaping_dead_map[offset]
for var_name in sorted(escape_dead_set):
ir_block.prepend(ir.Del(var_name, loc=ir_block.body[0].loc))
def op_DELETE_FAST(self, inst):
dstname = self.code_locals[inst.arg]
self.current_block.append(ir.Del(dstname, loc=self.loc))
def test_del(self):
a = ir.Del(self.var_a.name, self.loc1)
b = ir.Del(self.var_a.name, self.loc1)
c = ir.Del(self.var_a.name, self.loc2)
d = ir.Del(self.var_b.name, self.loc1)
self.check(a, same=[b, c], different=[d])