def build_dependencies(self):
""" This is basically building the definition-use chain and saving this
information in a graph structure. This is the same as calculating
the reaching definitions and the 'looking back' whenever it is used.
Write After Read, Write After Write dependencies are not possible,
the operations are in SSA form
"""
tracker = DefTracker(self)
#
label_pos = 0
jump_pos = len(self.nodes)-1
intformod = IntegralForwardModification(self.memory_refs, self.index_vars,
self.comparison_vars, self.invariant_vars)
# pass 1
for i,node in enumerate(self.nodes):
op = node.op
if rop.is_always_pure(op.opnum):
node.setpriority(1)
if rop.is_guard(op.opnum):
node.setpriority(2)
# the label operation defines all operations at the
# beginning of the loop
intformod.inspect_operation(op,node)
# definition of a new variable
if op.type != 'v':
# In SSA form. Modifications get a new variable
tracker.define(op, node)
# usage of defined variables
if rop.is_always_pure(op.opnum) or rop.is_final(op.opnum):
# normal case every arguments definition is set
for arg in op.getarglist():
tracker.depends_on_arg(arg, node)
elif rop.is_guard(op.opnum):
if node.exits_early():
pass
else:
# consider cross iterations?
if len(self.guards) > 0:
last_guard = self.guards[-1]
last_guard.edge_to(node, failarg=True, label="guardorder")
for nonpure in tracker.non_pure:
nonpure.edge_to(node, failarg=True, label="nonpure")
tracker.non_pure = []
self.guards.append(node)
self.build_guard_dependencies(node, tracker)
else:
self.build_non_pure_dependencies(node, tracker)
def build_dependencies(self):
""" This is basically building the definition-use chain and saving this
information in a graph structure. This is the same as calculating
the reaching definitions and the 'looking back' whenever it is used.
Write After Read, Write After Write dependencies are not possible,
the operations are in SSA form
"""
tracker = DefTracker(self)
#
label_pos = 0
jump_pos = len(self.nodes)-1
intformod = IntegralForwardModification(self.memory_refs, self.index_vars,
self.comparison_vars, self.invariant_vars)
# pass 1
for i,node in enumerate(self.nodes):
op = node.op
if rop.is_always_pure(op.opnum):
node.setpriority(1)
if rop.is_guard(op.opnum):
node.setpriority(2)
# the label operation defines all operations at the
# beginning of the loop
intformod.inspect_operation(op,node)
# definition of a new variable
if op.type != 'v':
# In SSA form. Modifications get a new variable
tracker.define(op, node)
# usage of defined variables
if rop.is_always_pure(op.opnum) or rop.is_final(op.opnum):
# normal case every arguments definition is set
for arg in op.getarglist():
tracker.depends_on_arg(arg, node)
elif rop.is_guard(op.opnum):
if node.exits_early():
pass
else:
# consider cross iterations?
if len(self.guards) > 0:
last_guard = self.guards[-1]
last_guard.edge_to(node, failarg=True, label="guardorder")
for nonpure in tracker.non_pure:
nonpure.edge_to(node, failarg=True, label="nonpure")
tracker.non_pure = []
self.guards.append(node)
self.build_guard_dependencies(node, tracker)
else:
self.build_non_pure_dependencies(node, tracker)
def is_always_pure(self, exclude_first=False, exclude_last=False):
last = len(self.path)-1
count = len(self.path)
i = 0
if exclude_first:
i += 1
if exclude_last:
count -= 1
while i < count:
node = self.path[i]
if node.is_imaginary():
i += 1
continue
op = node.getoperation()
if rop.is_guard(op.opnum):
descr = op.getdescr()
if not descr:
return False
assert isinstance(descr, AbstractFailDescr)
if not descr.exits_early():
return False
elif not rop.is_always_pure(op.opnum):
return False
i += 1
return True
def produce_potential_short_preamble_ops(self, sb):
ops = self.optimizer._newoperations
for i, op in enumerate(ops):
if rop.is_always_pure(op.opnum):
sb.add_pure_op(op)
if rop.is_ovf(
op.opnum) and ops[i +
1].getopnum() == rop.GUARD_NO_OVERFLOW:
sb.add_pure_op(op)
for i in self.call_pure_positions:
op = ops[i]
# don't move call_pure_with_exception in the short preamble...
# issue #2015
# Also, don't move cond_call_value in the short preamble.
# The issue there is that it's usually pointless to try to
# because the 'value' argument is typically not a loop
# invariant, and would really need to be in order to end up
# in the short preamble. Maybe the code works anyway in the
# other rare case, but better safe than sorry and don't try.
effectinfo = op.getdescr().get_extra_info()
if not effectinfo.check_can_raise(ignore_memoryerror=True):
assert rop.is_call(op.opnum)
if not OpHelpers.is_cond_call_value(op.opnum):
sb.add_pure_op(op)
def is_always_pure(self, exclude_first=False, exclude_last=False):
last = len(self.path)-1
count = len(self.path)
i = 0
if exclude_first:
i += 1
if exclude_last:
count -= 1
while i < count:
node = self.path[i]
if node.is_imaginary():
i += 1
continue
op = node.getoperation()
if rop.is_guard(op.opnum):
descr = op.getdescr()
if not descr:
return False
assert isinstance(descr, AbstractFailDescr)
if not descr.exits_early():
return False
elif not rop.is_always_pure(op.opnum):
return False
i += 1
return True
def produce_potential_short_preamble_ops(self, sb):
ops = self.optimizer._newoperations
for i, op in enumerate(ops):
if rop.is_always_pure(op.opnum):
sb.add_pure_op(op)
if rop.is_ovf(
op.opnum) and ops[i +
1].getopnum() == rop.GUARD_NO_OVERFLOW:
sb.add_pure_op(op)
for i in self.call_pure_positions:
op = ops[i]
# don't move call_pure_with_exception in the short preamble...
# issue #2015
effectinfo = op.getdescr().get_extra_info()
if not effectinfo.check_can_raise(ignore_memoryerror=True):
assert rop.is_call(op.opnum)
sb.add_pure_op(op)
def optimize_default(self, op):
canfold = rop.is_always_pure(op.opnum)
if rop.is_ovf(op.opnum):
self.postponed_op = op
return
if self.postponed_op:
nextop = op
op = self.postponed_op
self.postponed_op = None
canfold = nextop.getopnum() == rop.GUARD_NO_OVERFLOW
else:
nextop = None
save = False
if canfold:
for i in range(op.numargs()):
if self.get_constant_box(op.getarg(i)) is None:
break
else:
# all constant arguments: constant-fold away
resbox = self.optimizer.constant_fold(op)
# note that INT_xxx_OVF is not done from here, and the
# overflows in the INT_xxx operations are ignored
self.optimizer.make_constant(op, resbox)
return
# did we do the exact same operation already?
recentops = self.getrecentops(op.getopnum())
save = True
oldop = recentops.lookup(self.optimizer, op)
if oldop is not None:
self.optimizer.make_equal_to(op, oldop)
return
# otherwise, the operation remains
self.emit_operation(op)
if rop.returns_bool_result(op.opnum):
self.getintbound(op).make_bool()
if save:
recentops = self.getrecentops(op.getopnum())
recentops.add(op)
if nextop:
self.emit_operation(nextop)
def produce_potential_short_preamble_ops(self, sb):
ops = self.optimizer._newoperations
for i, op in enumerate(ops):
if rop.is_always_pure(op.opnum):
sb.add_pure_op(op)
if rop.is_ovf(op.opnum) and ops[i + 1].getopnum() == rop.GUARD_NO_OVERFLOW:
sb.add_pure_op(op)
for i in self.call_pure_positions:
op = ops[i]
# don't move call_pure_with_exception in the short preamble...
# issue #2015
# Also, don't move cond_call_value in the short preamble.
# The issue there is that it's usually pointless to try to
# because the 'value' argument is typically not a loop
# invariant, and would really need to be in order to end up
# in the short preamble. Maybe the code works anyway in the
# other rare case, but better safe than sorry and don't try.
effectinfo = op.getdescr().get_extra_info()
if not effectinfo.check_can_raise(ignore_memoryerror=True):
assert rop.is_call(op.opnum)
if not OpHelpers.is_cond_call_value(op.opnum):
sb.add_pure_op(op)
def optimize_default(self, op):
canfold = rop.is_always_pure(op.opnum)
if rop.is_ovf(op.opnum):
self.postponed_op = op
return
if self.postponed_op:
nextop = op
op = self.postponed_op
self.postponed_op = None
canfold = nextop.getopnum() == rop.GUARD_NO_OVERFLOW
else:
nextop = None
save = False
if canfold:
for i in range(op.numargs()):
if self.get_constant_box(op.getarg(i)) is None:
break
else:
# all constant arguments: constant-fold away
resbox = self.optimizer.constant_fold(op)
# note that INT_xxx_OVF is not done from here, and the
# overflows in the INT_xxx operations are ignored
self.optimizer.make_constant(op, resbox)
return
# did we do the exact same operation already?
recentops = self.getrecentops(op.getopnum())
save = True
oldop = recentops.lookup(self.optimizer, op)
if oldop is not None:
self.optimizer.make_equal_to(op, oldop)
return
# otherwise, the operation remains
return self.emit_result(DefaultOptimizationResult(self, op, save, nextop))
def is_pure(self):
return rop.is_always_pure(self.op.getopnum())
def is_pure(self):
return rop.is_always_pure(self.op.getopnum())