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import Nodes
import ExprNodes
import PyrexTypes
import Visitor
def unwrap_node(node):
while isinstance(node, ExprNodes.PersistentNode):
node = node.arg
return node
def is_common_value(a, b):
a = unwrap_node(a)
b = unwrap_node(b)
if isinstance(a, ExprNodes.NameNode) and isinstance(b, ExprNodes.NameNode):
return a.name == b.name
if isinstance(a, ExprNodes.AttributeNode) and isinstance(b, ExprNodes.AttributeNode):
return not a.is_py_attr and is_common_value(a.obj, b.obj) and a.attribute == b.attribute
return False
class SwitchTransform(Visitor.VisitorTransform):
"""
This transformation tries to turn long if statements into C switch statements.
The requirement is that every clause be an (or of) var == value, where the var
is common among all clauses and both var and value are ints.
"""
def extract_conditions(self, cond):
if isinstance(cond, ExprNodes.CoerceToTempNode):
cond = cond.arg
if isinstance(cond, ExprNodes.TypecastNode):
cond = cond.operand
if (isinstance(cond, ExprNodes.PrimaryCmpNode)
and cond.cascade is None
and cond.operator == '=='
and not cond.is_python_comparison()):
if is_common_value(cond.operand1, cond.operand1):
if isinstance(cond.operand2, ExprNodes.ConstNode):
return cond.operand1, [cond.operand2]
elif hasattr(cond.operand2, 'entry') and cond.operand2.entry and cond.operand2.entry.is_const:
return cond.operand1, [cond.operand2]
if is_common_value(cond.operand2, cond.operand2):
if isinstance(cond.operand1, ExprNodes.ConstNode):
return cond.operand2, [cond.operand1]
elif hasattr(cond.operand1, 'entry') and cond.operand1.entry and cond.operand1.entry.is_const:
return cond.operand2, [cond.operand1]
elif (isinstance(cond, ExprNodes.BoolBinopNode)
and cond.operator == 'or'):
t1, c1 = self.extract_conditions(cond.operand1)
t2, c2 = self.extract_conditions(cond.operand2)
if is_common_value(t1, t2):
return t1, c1+c2
return None, None
def visit_IfStatNode(self, node):
self.visitchildren(node)
common_var = None
case_count = 0
cases = []
for if_clause in node.if_clauses:
var, conditions = self.extract_conditions(if_clause.condition)
if var is None:
return node
elif common_var is not None and not is_common_value(var, common_var):
return node
elif not var.type.is_int or sum([not cond.type.is_int for cond in conditions]):
return node
else:
common_var = var
case_count += len(conditions)
cases.append(Nodes.SwitchCaseNode(pos = if_clause.pos,
conditions = conditions,
body = if_clause.body))
if case_count < 2:
return node
common_var = unwrap_node(common_var)
return Nodes.SwitchStatNode(pos = node.pos,
test = common_var,
cases = cases,
else_clause = node.else_clause)
def visit_Node(self, node):
self.visitchildren(node)
return node
class FlattenInListTransform(Visitor.VisitorTransform):
"""
This transformation flattens "x in [val1, ..., valn]" into a sequential list
of comparisons.
"""
def visit_PrimaryCmpNode(self, node):
self.visitchildren(node)
if node.cascade is not None:
return node
elif node.operator == 'in':
conjunction = 'or'
eq_or_neq = '=='
elif node.operator == 'not_in':
conjunction = 'and'
eq_or_neq = '!='
else:
return node
if isinstance(node.operand2, ExprNodes.TupleNode) or isinstance(node.operand2, ExprNodes.ListNode):
args = node.operand2.args
if len(args) == 0:
return ExprNodes.BoolNode(pos = node.pos, value = node.operator == 'not_in')
else:
lhs = ExprNodes.PersistentNode(node.operand1, len(args))
conds = []
for arg in args:
cond = ExprNodes.PrimaryCmpNode(
pos = node.pos,
operand1 = lhs,
operator = eq_or_neq,
operand2 = arg,
cascade = None)
conds.append(ExprNodes.TypecastNode(
pos = node.pos,
operand = cond,
type = PyrexTypes.c_bint_type))
def concat(left, right):
return ExprNodes.BoolBinopNode(
pos = node.pos,
operator = conjunction,
operand1 = left,
operand2 = right)
return reduce(concat, conds)
else:
return node
def visit_Node(self, node):
self.visitchildren(node)
return node
class FinalOptimizePhase(Visitor.CythonTransform):
"""
This visitor handles several commuting optimizations, and is run
just before the C code generation phase.
The optimizations currently implemented in this class are:
- Eliminate None assignment and refcounting for first assignment.
- isinstance -> typecheck for cdef types
"""
def visit_SingleAssignmentNode(self, node):
if node.first:
lhs = node.lhs
lhs.lhs_of_first_assignment = True
if isinstance(lhs, ExprNodes.NameNode) and lhs.entry.type.is_pyobject:
# Have variable initialized to 0 rather than None
lhs.entry.init_to_none = False
lhs.entry.init = 0
return node
def visit_SimpleCallNode(self, node):
self.visitchildren(node)
if node.function.type.is_cfunction and isinstance(node.function, ExprNodes.NameNode):
if node.function.name == 'isinstance':
type_arg = node.args[1]
if type_arg.type.is_builtin_type and type_arg.type.name == 'type':
object_module = self.context.find_module('python_object')
node.function.entry = object_module.lookup('PyObject_TypeCheck')
if node.function.entry is None:
return node # only happens when there was an error earlier
node.function.type = node.function.entry.type
PyTypeObjectPtr = PyrexTypes.CPtrType(object_module.lookup('PyTypeObject').type)
node.args[1] = ExprNodes.CastNode(node.args[1], PyTypeObjectPtr)
return node
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