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from rpython.translator.backendopt import graphanalyze
from rpython.rtyper.lltypesystem import lltype
from rpython.tool.ansi_print import AnsiLogger
log = AnsiLogger("finalizer")
class FinalizerError(Exception):
"""__del__() is used for lightweight RPython destructors,
but the FinalizerAnalyzer found that it is not lightweight.
The set of allowed operations is restrictive for a good reason
- it's better to be safe. Specifically disallowed operations:
* anything that escapes self
* anything that can allocate
"""
class FinalizerAnalyzer(graphanalyze.BoolGraphAnalyzer):
""" Analyzer that determines whether a finalizer is lightweight enough
so it can be called without all the complicated logic in the garbage
collector.
"""
ok_operations = ['ptr_nonzero', 'ptr_eq', 'ptr_ne', 'free', 'same_as',
'direct_ptradd', 'force_cast', 'track_alloc_stop',
'raw_free', 'adr_eq', 'adr_ne',
'debug_print']
def analyze_light_finalizer(self, graph):
if getattr(graph.func, '_must_be_light_finalizer_', False):
self._must_be_light = graph
result = self.analyze_direct_call(graph)
del self._must_be_light
if result is self.top_result():
msg = '%s\nIn %r' % (FinalizerError.__doc__, graph)
raise FinalizerError(msg)
else:
result = self.analyze_direct_call(graph)
#if result is self.top_result():
# log.red('old-style non-light finalizer: %r' % (graph,))
return result
def analyze_simple_operation(self, op, graphinfo):
if op.opname in self.ok_operations:
return self.bottom_result()
if (op.opname.startswith('int_') or op.opname.startswith('float_')
or op.opname.startswith('uint_') or op.opname.startswith('cast_')):
return self.bottom_result()
if op.opname == 'setfield' or op.opname == 'bare_setfield':
TP = op.args[2].concretetype
if not isinstance(TP, lltype.Ptr) or TP.TO._gckind == 'raw':
# primitive type
return self.bottom_result()
if op.opname == 'getfield':
TP = op.result.concretetype
if not isinstance(TP, lltype.Ptr) or TP.TO._gckind == 'raw':
# primitive type
return self.bottom_result()
if not hasattr(self, '_must_be_light'):
return self.top_result()
msg = '%s\nFound this forbidden operation:\n%r\nin %r\nfrom %r' % (
FinalizerError.__doc__, op, graphinfo, self._must_be_light)
raise FinalizerError(msg)
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