class ValueRangeAnalyis(SyntaxVisitor):
def __init__(self):
SyntaxVisitor.__init__(self)
self.ranges = {}
self.old_values = ScopedDict()
self.old_values.push()
def get(self, expr):
c = expr.__class__
if expr.type.__class__ is NoneT:
return const_none
elif c is Const:
return Interval(expr.value, expr.value)
elif c is Var and expr.name in self.ranges:
return self.ranges[expr.name]
elif c is Tuple:
elt_values = [self.get(elt) for elt in expr.elts]
return mk_tuple(elt_values)
elif c is TupleProj:
tup = self.get(expr.tuple)
idx = unwrap_constant(expr.index)
if tup.__class__ is TupleOfIntervals:
return tup.elts[idx]
elif c is Slice:
start = self.get(expr.start)
stop = self.get(expr.stop)
if expr.step.type == NoneType:
step = const_one
else:
step = self.get(expr.step)
return mk_slice(start, stop, step)
elif c is Shape:
ndims = get_rank(expr.array.type)
return mk_tuple([positive_interval] * ndims)
elif c is Attribute:
if expr.name == 'shape':
ndims = get_rank(expr.value.type)
return mk_tuple([positive_interval] * ndims)
elif expr.name == 'start':
sliceval = self.get(expr.value)
if isinstance(sliceval, SliceOfIntervals):
return sliceval.start
elif expr.name == 'stop':
sliceval = self.get(expr.value)
if isinstance(sliceval, SliceOfIntervals):
return sliceval.stop
elif expr.name == 'step':
sliceval = self.get(expr.value)
if isinstance(sliceval, SliceOfIntervals):
return sliceval.step
elif c is PrimCall:
p = expr.prim
if p.nin == 2:
x = self.get(expr.args[0])
y = self.get(expr.args[1])
if p == prims.add:
return self.add_range(x,y)
elif p == prims.subtract:
return self.sub_range(x,y)
elif p == prims.multiply:
return self.mul_range(x,y)
elif p.nin == 1:
x = self.get(expr.args[0])
if p == prims.negative:
return self.neg_range(x)
return any_value
def set(self, name, val):
if val is not None and val is not unknown_value:
old_value = self.ranges.get(name, unknown_value)
self.ranges[name] = val
if old_value != val and old_value is not unknown_value:
self.old_values[name] = old_value
def add_range(self, x, y):
if not isinstance(x, Interval) or not isinstance(y, Interval):
return any_value
return Interval (x.lower + y.lower, x.upper + y.upper)
def sub_range(self, x, y):
if not isinstance(x, Interval) or not isinstance(y, Interval):
return any_value
return Interval(x.lower - y.upper, x.upper - y.lower)
def mul_range(self, x, y):
if not isinstance(x, Interval) or not isinstance(y, Interval):
return any_value
xl, xu = x.lower, x.upper
yl, yu = y.lower, y.upper
products = (xl * yl, xl * yu, xu * yl, xu * yu)
lower = min(products)
upper = max(products)
return Interval(lower, upper)
def neg_range(self, x):
if not isinstance(x, Interval):
return any_value
return Interval(-x.upper, -x.lower)
def visit_Assign(self, stmt):
if stmt.lhs.__class__ is Var:
name = stmt.lhs.name
v = self.get(stmt.rhs)
self.set(name, v)
def visit_merge_left(self, phi_nodes):
for (k, (left, _)) in phi_nodes.iteritems():
left_val = self.get(left)
self.set(k, left_val)
def visit_merge(self, phi_nodes):
for (k, (left,right)) in phi_nodes.iteritems():
left_val = self.get(left)
right_val = self.get(right)
self.set(k, left_val.combine(right_val))
def visit_Select(self, expr):
return self.get(expr.true_value).combine(self.get(expr.false_value))
def always_positive(self, x, inclusive = True):
if not isinstance(x, Interval):
return False
elif inclusive:
return x.lower >= 0
else:
return x.lower > 0
def always_negative(self, x, inclusive = True):
if not isinstance(x, Interval):
return False
elif inclusive:
return x.upper <= 0
else:
return x.upper < 0
def widen(self, old_values):
for (k, oldv) in old_values.iteritems():
newv = self.ranges[k]
if oldv != newv:
self.ranges[k] = oldv.widen(newv)
def run_loop(self, body, merge):
# run loop for the first time
self.old_values.push()
self.visit_merge_left(merge)
self.visit_block(body)
self.visit_merge(merge)
#run loop for the second time
self.visit_block(body)
self.visit_merge(merge)
old_values = self.old_values.pop()
self.widen(old_values)
# TODO: verify that it's safe not to run loop with widened values
#self.visit_block(body)
#self.visit_merge(merge)
def visit_While(self, stmt):
self.run_loop(stmt.body, stmt.merge)
def visit_ForLoop(self, stmt):
start = self.get(stmt.start)
stop = self.get(stmt.stop)
step = self.get(stmt.step)
name = stmt.var.name
iterator_range = any_value
if isinstance(start, Interval) and isinstance(stop, Interval):
lower = min (start.lower, start.upper, stop.lower, stop.upper)
upper = max (start.lower, start.upper, stop.lower, stop.upper)
iterator_range = Interval(lower,upper)
elif isinstance(start, Interval) and isinstance(step, Interval):
if self.always_positive(step):
iterator_range = Interval(start.lower, np.inf)
elif self.always_negative(step, inclusive = False):
iterator_range = Interval(-np.inf, start.upper)
elif isinstance(stop, Interval) and isinstance(step, Interval):
if self.always_positive(step):
iterator_range = Interval(-np.inf, stop.upper)
elif self.always_negative(step, inclusive = False):
iterator_range = Interval(stop.lower, np.inf)
self.set(name, iterator_range)
self.run_loop(stmt.body, stmt.merge)
class Simplify(Transform):
def __init__(self):
transform.Transform.__init__(self)
# associate var names with any immutable values
# they are bound to
self.bindings = ScopedDict()
# which expressions have already been computed
# and stored in some variable?
self.available_expressions = ScopedDict()
def pre_apply(self, fn):
ma = TypeBasedMutabilityAnalysis()
# which types have elements that might
# change between two accesses?
self.mutable_types = ma.visit_fn(fn)
self.use_counts = use_count(fn)
def immutable_type(self, t):
return t not in self.mutable_types
def children(self, expr, allow_mutable = False):
c = expr.__class__
if c is Const or c is Var:
return ()
elif c is PrimCall or c is Closure:
return expr.args
elif c is ClosureElt:
return (expr.closure,)
elif c is Tuple:
return expr.elts
elif c is TupleProj:
return (expr.tuple,)
# WARNING: this is only valid
# if attributes are immutable
elif c is Attribute:
return (expr.value,)
elif c is Slice:
return (expr.start, expr.stop, expr.step)
elif c is Cast:
return (expr.value,)
elif c is Map or c is OuterMap or c is IndexMap:
return expr.args
elif c is Scan or c is Reduce or c is IndexReduce or c is FilterReduce:
args = tuple(expr.args)
init = (expr.init,) if expr.init else ()
return init + args
elif c is Call:
# assume all Calls might modify their arguments
if allow_mutable or all(self.immutable(arg) for arg in expr.args):
return expr.args
else:
return None
if allow_mutable or self.immutable_type(expr.type):
if c is Array:
return expr.elts
elif c is ArrayView:
return (expr.data, expr.shape, expr.strides, expr.offset, expr.size)
elif c is Struct:
return expr.args
elif c is AllocArray:
return (expr.shape,)
elif c is Attribute:
return (expr.value,)
return None
_immutable_classes = set([Const, Var,
Closure, ClosureElt,
Tuple, TupleProj,
Cast, PrimCall,
TypedFn, UntypedFn,
ArrayView,
Slice,
])
def immutable(self, expr):
"""
TODO: make all this mutability/immutability stuff sane
"""
klass = expr.__class__
result = (klass in self._immutable_classes and
(all(self.immutable(c) for c in expr.children()))) or \
(klass is Attribute and isinstance(expr.type, ImmutableT))
return result
def temp(self, expr, name = None, use_count = 1):
"""
Wrapper around Codegen.assign_name which also updates bindings and
use_counts
"""
if self.is_simple(expr):
return expr
else:
new_var = self.assign_name(expr, name = name)
self.bindings[new_var.name] = expr
self.use_counts[new_var.name] = use_count
return new_var
def transform_expr(self, expr):
if self.is_simple(expr):
if expr.type == NoneType:
return none
else:
return Transform.transform_expr(self, expr)
stored = self.available_expressions.get(expr)
if stored is not None:
return stored
return Transform.transform_expr(self, expr)
def transform_Var(self, expr):
t = expr.type
if t.__class__ is NoneT:
return none
elif t.__class__ is SliceT and \
t.start_type == NoneType and \
t.stop_type == NoneType and \
t.step_type == NoneType:
return slice_none
name = expr.name
prev_expr = expr
while name in self.bindings:
prev_expr = expr
expr = self.bindings[name]
if expr.__class__ is Var:
name = expr.name
else:
break
c = expr.__class__
if c is Var or c is Const:
return expr
else:
return prev_expr
def transform_Cast(self, expr):
v = self.transform_expr(expr.value)
if v.type == expr.type:
return v
elif v.__class__ is Const and isinstance(expr.type, ScalarT):
return Const(expr.type.dtype.type(v.value), type = expr.type)
elif self.is_simple(v):
expr.value = v
return expr
else:
expr.value = self.assign_name(v)
return expr
def transform_Attribute(self, expr):
v = self.transform_expr(expr.value)
if v.__class__ is Var and v.name in self.bindings:
stored_v = self.bindings[v.name]
c = stored_v.__class__
if c is Var or c is Struct:
v = stored_v
elif c is ArrayView:
if expr.name == 'shape':
return self.transform_expr(stored_v.shape)
elif expr.name == 'strides':
return self.transform_expr(stored_v.strides)
elif expr.name == 'data':
return self.transform_expr(stored_v.data)
elif c is AllocArray:
if expr.name == 'shape':
return self.transform_expr(stored_v.shape)
elif c is Slice:
if expr.name == "start":
return self.transform_expr(stored_v.start)
elif expr.name == "stop":
return self.transform_expr(stored_v.stop)
else:
assert expr.name == "step", "Unexpected attribute for slice: %s" % expr.name
return self.transform_expr(stored_v.step)
if v.__class__ is Struct:
idx = v.type.field_pos(expr.name)
return v.args[idx]
elif v.__class__ is not Var:
v = self.temp(v, "struct")
if expr.value == v:
return expr
else:
return Attribute(value = v, name = expr.name, type = expr.type)
def transform_Closure(self, expr):
expr.args = tuple(self.transform_simple_exprs(expr.args))
return expr
def transform_Tuple(self, expr):
expr.elts = tuple( self.transform_simple_exprs(expr.elts))
return expr
def transform_TupleProj(self, expr):
idx = expr.index
assert isinstance(idx, int), \
"TupleProj index must be an integer, got: " + str(idx)
new_tuple = self.transform_expr(expr.tuple)
if new_tuple.__class__ is Var and new_tuple.name in self.bindings:
tuple_expr = self.bindings[new_tuple.name]
if tuple_expr.__class__ is Tuple:
assert idx < len(tuple_expr.elts), \
"Too few elements in tuple %s : %s, elts = %s" % (expr, tuple_expr.type, tuple_expr.elts)
return tuple_expr.elts[idx]
elif tuple_expr.__class__ is Struct:
assert idx < len(tuple_expr.args), \
"Too few args in closure %s : %s, elts = %s" % (expr, tuple_expr.type, tuple_expr.elts)
return tuple_expr.args[idx]
if not self.is_simple(new_tuple):
new_tuple = self.assign_name(new_tuple, "tuple")
expr.tuple = new_tuple
return expr
def transform_ClosureElt(self, expr):
idx = expr.index
assert isinstance(idx, int), \
"ClosureElt index must be an integer, got: " + str(idx)
new_closure = self.transform_expr(expr.closure)
if new_closure.__class__ is Var and new_closure.name in self.bindings:
closure_expr = self.bindings[new_closure.name]
if closure_expr.__class__ is Closure:
return closure_expr.args[idx]
if not self.is_simple(new_closure):
new_closure = self.assign_name(new_closure, "closure")
expr.closure = new_closure
return expr
def transform_Call(self, expr):
fn = self.transform_expr(expr.fn)
args = self.transform_simple_exprs(expr.args)
if fn.type.__class__ is ClosureT:
closure_elts = self.closure_elts(fn)
combined_args = tuple(closure_elts) + tuple(args)
if fn.type.fn.__class__ is TypedFn:
fn = fn.type.fn
else:
assert isinstance(fn.type.fn, UntypedFn)
from .. type_inference import specialize
fn = specialize(fn, get_types(combined_args))
assert fn.return_type == expr.type
return Call(fn, combined_args, type = fn.return_type)
else:
expr.fn = fn
expr.args = args
return expr
def transform_simple_expr(self, expr, name = None):
if name is None:
name = "temp"
result = self.transform_expr(expr)
if not self.is_simple(result):
return self.assign_name(result, name)
else:
return result
def transform_simple_exprs(self, args):
return [self.transform_simple_expr(x) for x in args]
def transform_Array(self, expr):
expr.elts = tuple(self.transform_simple_exprs(expr.elts))
return expr
def transform_Slice(self, expr):
expr.start = self.transform_simple_expr(expr.start)
expr.stop = self.transform_simple_expr(expr.stop)
expr.step = self.transform_simple_expr(expr.step)
return expr
def transform_index_expr(self, expr):
if expr.__class__ is Tuple:
new_elts = []
for elt in expr.elts:
new_elt = self.transform_expr(elt)
if not self.is_simple(new_elt) and new_elt.type.__class__ is not SliceT:
new_elt = self.temp(new_elt, "index_tuple_elt")
new_elts.append(new_elt)
expr.elts = tuple(new_elts)
return expr
else:
return self.transform_expr(expr)
def transform_Index(self, expr):
expr.value = self.transform_expr(expr.value)
expr.index = self.transform_index_expr(expr.index)
if expr.value.__class__ is Array and expr.index.__class__ is Const:
assert isinstance(expr.index.value, (int, long)) and \
len(expr.value.elts) > expr.index.value
return expr.value.elts[expr.index.value]
# take expressions like "a[i][j]" and turn them into "a[i,j]"
if expr.value.__class__ is Index:
base_array = expr.value.value
if isinstance(base_array.type, ArrayT):
base_index = expr.value.index
if isinstance(base_index.type, TupleT):
indices = self.tuple_elts(base_index)
else:
assert isinstance(base_index.type, ScalarT), \
"Unexpected index type %s : %s in %s" % (base_index, base_index.type, expr)
indices = [base_index]
if isinstance(expr.index.type, TupleT):
indices = tuple(indices) + tuple(self.tuple_elts(expr.index))
else:
assert isinstance(expr.index.type, ScalarT), \
"Unexpected index type %s : %s in %s" % (expr.index, expr.index.type, expr)
indices = tuple(indices) + (expr.index,)
expr = self.index(base_array, self.tuple(indices))
return self.transform_expr(expr)
if expr.value.__class__ is not Var:
expr.value = self.temp(expr.value, "array")
return expr
def transform_Struct(self, expr):
new_args = self.transform_simple_exprs(expr.args)
return syntax.Struct(new_args, type = expr.type)
def transform_Select(self, expr):
cond = self.transform_expr(expr.cond)
trueval = self.transform_expr(expr.true_value)
falseval = self.transform_expr(expr.false_value)
if is_true(cond):
return trueval
elif is_false(cond):
return falseval
elif trueval == falseval:
return trueval
else:
expr.cond = cond
expr.false_value = falseval
expr.true_value = trueval
return expr
def transform_PrimCall(self, expr):
args = self.transform_simple_exprs(expr.args)
prim = expr.prim
if all_constants(args):
return syntax.Const(value = prim.fn(*collect_constants(args)),
type = expr.type)
if len(args) == 1:
x = args[0]
if prim == prims.logical_not:
if is_false(x):
return true
elif is_true(x):
return false
if len(args) == 2:
x,y = args
if prim == prims.add:
if is_zero(x):
return y
elif is_zero(y):
return x
if y.__class__ is Const and y.value < 0:
expr.prim = prims.subtract
expr.args = (x, Const(value = -y.value, type = y.type))
return expr
elif x.__class__ is Const and x.value < 0:
expr.prim = prims.subtract
expr.args = (y, Const(value = -x.value, type = x.type))
return expr
elif prim == prims.subtract:
if is_zero(y):
return x
elif is_zero(x) and y.__class__ is Var:
stored = self.bindings.get(y.name)
# 0 - (a * b) --> -a * b |or| a * -b
if stored and stored.__class__ is PrimCall and stored.prim == prims.multiply:
a,b = stored.args
if a.__class__ is Const:
expr.prim = prims.multiply
neg_a = Const(value = -a.value, type = a.type)
expr.args = [neg_a, b]
return expr
elif b.__class__ is Const:
expr.prim = prims.multiply
neg_b = Const(value = -b.value, type = b.type)
expr.args = [a, neg_b]
return expr
elif prim == prims.multiply:
if is_one(x):
return y
elif is_one(y):
return x
elif is_zero(x):
return x
elif is_zero(y):
return y
elif prim == prims.divide and is_one(y):
return x
elif prim == prims.power:
if is_one(y):
return self.cast(x, expr.type)
elif is_zero(y):
return one(expr.type)
elif y.__class__ is Const and y.value == 2:
return self.cast(self.mul(x, x, "sqr"), expr.type)
elif prim == prims.logical_and:
if is_true(x):
return y
elif is_false(x) or is_false(y):
return false
elif prim == prims.logical_or:
if is_true(x) or is_true(y):
return true
elif is_false(x) or is_false(y):
return false
expr.args = args
return expr
def transform_Map(self, expr):
expr.args = self.transform_simple_exprs(expr.args)
expr.fn = self.transform_expr(expr.fn)
expr.axis = self.transform_if_expr(expr.axis)
return expr
def transform_OuterMap(self, expr):
expr.args = self.transform_simple_exprs(expr.args)
expr.fn = self.transform_expr(expr.fn)
expr.axis = self.transform_if_expr(expr.axis)
return expr
def transform_shape(self, expr):
if isinstance(expr, Tuple):
expr.elts = tuple(self.transform_simple_exprs(expr.elts))
return expr
else:
return self.transform_simple_expr(expr)
def transform_ParFor(self, stmt):
stmt.bounds = self.transform_shape(stmt.bounds)
stmt.fn = self.transform_expr(stmt.fn)
return stmt
def transform_IndexMap(self, expr):
expr.fn = self.transform_expr(expr.fn)
expr.shape = self.transform_shape(expr.shape)
return expr
def transform_IndexReduce(self, expr):
expr.fn = self.transform_if_expr(expr.fn)
expr.combine = self.transform_expr(expr.combine)
expr.init = self.transform_if_expr(expr.init)
expr.shape = self.transform_shape(expr.shape)
return expr
def transform_IndexScan(self, expr):
expr.fn = self.transform_if_expr(expr.fn)
expr.combine = self.transform_expr(expr.combine)
expr.emit = self.transform_if_expr(expr.emit)
expr.init = self.transform_if_expr(expr.init)
expr.shape = self.transform_shape(expr.shape)
return expr
def transform_ConstArray(self, expr):
expr.shape = self.transform_shape(expr.shape)
expr.value = self.transform_simple_expr(expr.value)
return expr
def transform_ConstArrayLike(self, expr):
expr.array = self.transform_simple_expr(expr.array)
expr.value = self.transform_simple_expr(expr.value)
def transform_Reduce(self, expr):
init = self.transform_expr(expr.init)
if not self.is_simple(init):
expr.init = self.assign_name(init, 'init')
else:
expr.init = init
expr.args = self.transform_simple_exprs(expr.args)
expr.fn = self.transform_expr(expr.fn)
expr.combine = self.transform_expr(expr.combine)
return expr
def temp_in_block(self, expr, block, name = None):
"""
If we need a temporary variable not in the current top scope but in a
particular block, then use this function. (this function also modifies the
bindings dictionary)
"""
if name is None:
name = "temp"
var = self.fresh_var(expr.type, name)
block.append(Assign(var, expr))
self.bindings[var.name] = expr
return var
def set_binding(self, name, value):
assert value.__class__ is not Var or \
value.name != name, \
"Can't set name %s bound to itself" % name
self.bindings[name] = value
def bind_var(self, name, rhs):
if rhs.__class__ is Var:
old_val = self.bindings.get(rhs.name)
if old_val and self.is_simple(old_val):
self.set_binding(name, old_val)
else:
self.set_binding(name, rhs)
else:
self.set_binding(name, rhs)
def bind(self, lhs, rhs):
lhs_class = lhs.__class__
if lhs_class is Var:
self.bind_var(lhs.name, rhs)
elif lhs_class is Tuple and rhs.__class__ is Tuple:
assert len(lhs.elts) == len(rhs.elts)
for lhs_elt, rhs_elt in zip(lhs.elts, rhs.elts):
self.bind(lhs_elt, rhs_elt)
def transform_lhs_Index(self, lhs):
lhs.index = self.transform_index_expr(lhs.index)
if lhs.value.__class__ is Var:
stored = self.bindings.get(lhs.value.name)
if stored and stored.__class__ is Var:
lhs.value = stored
else:
lhs.value = self.assign_name(lhs.value, "array")
return lhs
def transform_lhs_Attribute(self, lhs):
# lhs.value = self.transform_expr(lhs.value)
return lhs
def transform_ExprStmt(self, stmt):
"""Don't run an expression unless it possibly has a side effect"""
v = self.transform_expr(stmt.value)
if self.immutable(v):
return None
else:
stmt.value = v
return stmt
def transform_Assign(self, stmt):
lhs = stmt.lhs
rhs = self.transform_expr(stmt.rhs)
lhs_class = lhs.__class__
rhs_class = rhs.__class__
if lhs_class is Var:
if lhs.type.__class__ is NoneT and self.use_counts.get(lhs.name,0) == 0:
return self.transform_stmt(ExprStmt(rhs))
elif self.immutable(rhs):
self.bind_var(lhs.name, rhs)
if rhs_class is not Var and rhs_class is not Const:
self.available_expressions.setdefault(rhs, lhs)
elif lhs_class is Tuple:
self.bind(lhs, rhs)
elif lhs_class is Index:
if rhs_class is Index and \
lhs.value == rhs.value and \
lhs.index == rhs.index:
# kill effect-free writes like x[i] = x[i]
return None
elif rhs_class is Var and \
lhs.value.__class__ is Var and \
lhs.value.name == rhs.name and \
lhs.index.type.__class__ is TupleT and \
all(elt_t == slice_none_t for elt_t in lhs.index.type.elt_types):
# also kill x[:] = x
return None
else:
lhs = self.transform_lhs_Index(lhs)
# when assigning x[j] = [1,2,3]
# just rewrite it as a sequence of element assignments
# to avoid
if lhs.type.__class__ is ArrayT and \
lhs.type.rank == 1 and \
rhs.__class__ is Array:
lhs_slice = self.assign_name(lhs, "lhs_slice")
for (elt_idx, elt) in enumerate(rhs.elts):
lhs_idx = self.index(lhs_slice, const_int(elt_idx), temp = False)
self.assign(lhs_idx, elt)
return None
elif not self.is_simple(rhs):
rhs = self.assign_name(rhs)
else:
assert lhs_class is Attribute
assert False, "Considering making attributes immutable"
lhs = self.transform_lhs_Attribute(lhs)
if rhs_class is Var and \
rhs.name in self.bindings and \
self.use_counts.get(rhs.name, 1) == 1:
self.use_counts[rhs.name] = 0
rhs = self.bindings[rhs.name]
stmt.lhs = lhs
stmt.rhs = rhs
return stmt
def transform_block(self, stmts, keep_bindings = False):
self.available_expressions.push()
self.bindings.push()
new_stmts = Transform.transform_block(self, stmts)
self.available_expressions.pop()
if not keep_bindings:
self.bindings.pop()
return new_stmts
def enter_loop(self, phi_nodes):
result = {}
for (k, (left,right)) in phi_nodes.iteritems():
new_left = self.transform_expr(left)
if new_left == right:
self.set_binding(k, new_left)
else:
result[k] = (new_left, right)
return result
def transform_merge(self, phi_nodes, left_block, right_block):
result = {}
for (k, (left, right)) in phi_nodes.iteritems():
new_left = self.transform_expr(left)
new_right = self.transform_expr(right)
if not isinstance(new_left, (Const, Var)):
new_left = self.temp_in_block(new_left, left_block)
if not isinstance(new_right, (Const, Var)):
new_right = self.temp_in_block(new_right, right_block)
if new_left == new_right:
# if both control flows yield the same value then
# we don't actually need the phi-bound variable, we can just
# replace the left value everywhere
self.assign(Var(name= k, type = new_left.type), new_left)
self.set_binding(k, new_left)
else:
result[k] = new_left, new_right
return result
def transform_If(self, stmt):
stmt.true = self.transform_block(stmt.true, keep_bindings = True)
stmt.false = self.transform_block(stmt.false, keep_bindings=True)
stmt.merge = self.transform_merge(stmt.merge,
left_block = stmt.true,
right_block = stmt.false)
self.bindings.pop()
self.bindings.pop()
stmt.cond = self.transform_simple_expr(stmt.cond, "cond")
if len(stmt.true) == 0 and len(stmt.false) == 0 and len(stmt.merge) <= 2:
for (lhs_name, (true_expr, false_expr)) in stmt.merge.items():
lhs_type = self.lookup_type(lhs_name)
lhs_var = Var(name = lhs_name, type = lhs_type)
assert true_expr.type == false_expr.type, \
"Unexpcted type mismatch: %s != %s" % (true_expr.type, false_expr.type)
rhs = Select(stmt.cond, true_expr, false_expr, type = true_expr.type)
self.bind_var(lhs_name, rhs)
self.assign(lhs_var, rhs)
return None
return stmt
def transform_loop_condition(self, expr, outer_block, loop_body, merge):
"""Normalize loop conditions so they are just simple variables"""
if self.is_simple(expr):
return self.transform_expr(expr)
else:
loop_carried_vars = [name for name in collect_var_names(expr)
if name in merge]
if len(loop_carried_vars) == 0:
return expr
left_values = [merge[name][0] for name in loop_carried_vars]
right_values = [merge[name][1] for name in loop_carried_vars]
left_cond = subst.subst_expr(expr, dict(zip(loop_carried_vars,
left_values)))
if not self.is_simple(left_cond):
left_cond = self.temp_in_block(left_cond, outer_block, name = "cond")
right_cond = subst.subst_expr(expr, dict(zip(loop_carried_vars,
right_values)))
if not self.is_simple(right_cond):
right_cond = self.temp_in_block(right_cond, loop_body, name = "cond")
cond_var = self.fresh_var(left_cond.type, "cond")
merge[cond_var.name] = (left_cond, right_cond)
return cond_var
def transform_While(self, stmt):
merge = self.enter_loop(stmt.merge)
stmt.body = self.transform_block(stmt.body)
stmt.merge = self.transform_merge(merge,
left_block = self.blocks.current(),
right_block = stmt.body)
stmt.cond = \
self.transform_loop_condition(stmt.cond,
outer_block = self.blocks.current(),
loop_body = stmt.body,
merge = stmt.merge)
return stmt
def transform_ForLoop(self, stmt):
merge = self.enter_loop(stmt.merge)
stmt.body = self.transform_block(stmt.body)
stmt.merge = self.transform_merge(merge,
left_block = self.blocks.current(),
right_block = stmt.body)
stmt.start = self.transform_simple_expr(stmt.start, 'start')
stmt.stop = self.transform_simple_expr(stmt.stop, 'stop')
if self.is_none(stmt.step):
stmt.step = one(stmt.start.type)
else:
stmt.step = self.transform_simple_expr(stmt.step, 'step')
# if a loop is only going to run for one iteration, might as well get rid of
# it
if stmt.start.__class__ is Const and \
stmt.stop.__class__ is Const and \
stmt.step.__class__ is Const:
if stmt.start.value >= stmt.stop.value:
for (var_name, (input_value, _)) in stmt.merge.iteritems():
var = Var(var_name, input_value.type)
self.blocks.append(Assign(var, input_value))
return None
elif stmt.start.value + stmt.step.value >= stmt.stop.value:
for (var_name, (input_value, _)) in stmt.merge.iteritems():
var = Var(var_name, input_value.type)
self.blocks.append(Assign(var, input_value))
self.assign(stmt.var, stmt.start)
self.blocks.top().extend(stmt.body)
return None
return stmt
def transform_Return(self, stmt):
new_value = self.transform_expr(stmt.value)
if new_value != stmt.value:
stmt.value = new_value
return stmt
class AST_Translator(ast.NodeVisitor):
def __init__(self,
globals_dict=None,
closure_cell_dict=None,
parent=None,
function_name = None,
filename = None):
# assignments which need to get prepended at the beginning of the
# function
self.globals = globals_dict
self.blocks = NestedBlocks()
self.parent = parent
self.scopes = ScopedDict()
self.globals_dict = globals_dict
self.closure_cell_dict = closure_cell_dict
# mapping from names/paths to either a closure cell reference or a
# global value
self.python_refs = OrderedDict()
self.original_outer_names = []
self.localized_outer_names = []
self.filename = filename
self.function_name = function_name
self.push()
def push(self, scope = None, block = None):
if scope is None:
scope = {}
if block is None:
block = []
self.scopes.push(scope)
self.blocks.push(block)
def pop(self):
scope = self.scopes.pop()
block = self.blocks.pop()
return scope, block
def fresh_name(self, original_name):
fresh_name = names.fresh(original_name)
self.scopes[original_name] = fresh_name
return fresh_name
def fresh_names(self, original_names):
return map(self.fresh_name, original_names)
def fresh_var(self, name):
return syntax.Var(self.fresh_name(name))
def fresh_vars(self, original_names):
return map(self.fresh_var, original_names)
def current_block(self):
return self.blocks.top()
def current_scope(self):
return self.scopes.top()
def syntax_to_value(self, expr):
if isinstance(expr, ast.Num):
return expr.n
elif isinstance(expr, ast.Tuple):
return tuple(self.syntax_to_value(elt) for elt in expr.elts)
elif isinstance(expr, ast.Name):
return self.lookup_global(expr.id)
elif isinstance(expr, ast.Attribute):
left = self.syntax_to_value(expr.value)
if isinstance(left, ExternalValue):
left = left.value
return getattr(left, expr.attr)
def lookup_global(self, key):
if isinstance(key, (list, tuple)):
assert len(key) == 1
key = key[0]
else:
assert isinstance(key, str), "Invalid global key: %s" % (key,)
if self.globals:
if key in self.globals:
return self.globals[key]
elif key in __builtin__.__dict__:
return __builtin__.__dict__[key]
else:
assert False, "Couldn't find global name %s" % key
else:
assert self.parent is not None
return self.parent.lookup_global(key)
def is_global(self, key):
if isinstance(key, (list, tuple)):
key = key[0]
if key in self.scopes:
return False
elif self.closure_cell_dict and key in self.closure_cell_dict:
return False
if self.globals:
return key in self.globals or key in __builtins__
assert self.parent is not None
return self.parent.is_global(key)
def local_ref_name(self, ref, python_name):
for (local_name, other_ref) in self.python_refs.iteritems():
if ref == other_ref:
return Var(local_name)
local_name = names.fresh(python_name)
self.scopes[python_name] = local_name
self.original_outer_names.append(python_name)
self.localized_outer_names.append(local_name)
self.python_refs[local_name] = ref
return Var(local_name)
def lookup(self, name):
#if name in reserved_names:
# return reserved_names[name]
if name in self.scopes:
return Var(self.scopes[name])
elif self.parent:
# don't actually keep the outer binding name, we just
# need to check that it's possible and tell the outer scope
# to register any necessary python refs
local_name = names.fresh(name)
self.scopes[name] = local_name
self.original_outer_names.append(name)
self.localized_outer_names.append(local_name)
return Var(local_name)
elif self.closure_cell_dict and name in self.closure_cell_dict:
ref = ClosureCellRef(self.closure_cell_dict[name], name)
return self.local_ref_name(ref, name)
elif self.is_global(name):
value = self.lookup_global(name)
if is_static_value(value):
return value_to_syntax(value)
elif isinstance(value, np.ndarray):
ref = GlobalValueRef(value)
return self.local_ref_name(ref, name)
else:
# assume that this is a module or object which will have some
# statically convertible value pulled out of it
return ExternalValue(value)
#else:
# assert False, "Can't use global value %s" % value
else:
raise NameNotFound(name)
def visit_list(self, nodes):
return map(self.visit, nodes)
def tuple_arg_assignments(self, elts, var):
"""
Recursively decompose a nested tuple argument like
def f((x,(y,z))):
...
into a single name and a series of assignments:
def f(tuple_arg):
x = tuple_arg[0]
tuple_arg_elt = tuple_arg[1]
y = tuple_arg_elt[0]
z = tuple_arg_elt[1]
"""
assignments = []
for (i, sub_arg) in enumerate(elts):
if isinstance(sub_arg, ast.Tuple):
name = "tuple_arg_elt"
else:
assert isinstance(sub_arg, ast.Name)
name = sub_arg.id
lhs = self.fresh_var(name)
stmt = Assign(lhs, syntax.Index(var, syntax.Const(i)))
assignments.append(stmt)
if isinstance(sub_arg, ast.Tuple):
more_stmts = self.tuple_arg_assignments(sub_arg.elts, lhs)
assignments.extend(more_stmts)
return assignments
def translate_args(self, args):
assert not args.kwarg
formals = FormalArgs()
assignments = []
for arg in args.args:
if isinstance(arg, ast.Name):
visible_name = arg.id
local_name = self.fresh_name(visible_name)
formals.add_positional(local_name, visible_name)
else:
assert isinstance(arg, ast.Tuple)
arg_name = self.fresh_name("tuple_arg")
formals.add_positional(arg_name)
var = Var(arg_name)
stmts = self.tuple_arg_assignments(arg.elts, var)
assignments.extend(stmts)
n_defaults = len(args.defaults)
if n_defaults > 0:
local_names = formals.positional[-n_defaults:]
for (k,expr) in zip(local_names, args.defaults):
formals.defaults[k] = self.syntax_to_value(expr)
if args.vararg:
assert isinstance(args.vararg, str)
formals.starargs = self.fresh_name(args.vararg)
return formals, assignments
def visit_Name(self, expr):
assert isinstance(expr, ast.Name), "Expected AST Name object: %s" % expr
return self.lookup(expr.id)
def create_phi_nodes(self, left_scope, right_scope, new_names = {}):
"""
Phi nodes make explicit the possible sources of each variable's values and
are needed when either two branches merge or when one was optionally taken.
"""
merge = {}
for (name, ssa_name) in left_scope.iteritems():
left = Var(ssa_name)
if name in right_scope:
right = Var(right_scope[name])
else:
try:
right = self.lookup(name)
except NameNotFound:
continue
if name in new_names:
new_name = new_names[name]
else:
new_name = self.fresh_name(name)
merge[new_name] = (left, right)
for (name, ssa_name) in right_scope.iteritems():
if name not in left_scope:
try:
left = self.lookup(name)
right = Var(ssa_name)
if name in new_names:
new_name = new_names[name]
else:
new_name = self.fresh_name(name)
merge[new_name] = (left, right)
except names.NameNotFound:
# for now skip over variables which weren't defined before
# a control flow split, which means that loop-local variables
# can't be used after the loop.
# TODO: Fix this. Maybe with 'undef' nodes?
pass
return merge
def visit_Index(self, expr):
return self.visit(expr.value)
def visit_Ellipsis(self, expr):
raise RuntimeError("Ellipsis operator unsupported")
def visit_Slice(self, expr):
"""
x[l:u:s]
Optional fields
expr.lower
expr.upper
expr.step
"""
start = self.visit(expr.lower) if expr.lower else none
stop = self.visit(expr.upper) if expr.upper else none
step = self.visit(expr.step) if expr.step else none
return syntax.Slice(start, stop, step)
def visit_ExtSlice(self, expr):
slice_elts = map(self.visit, expr.dims)
if len(slice_elts) > 1:
return syntax.Tuple(slice_elts)
else:
return slice_elts[0]
def visit_UnaryOp(self, expr):
ssa_val = self.visit(expr.operand)
# UAdd doesn't do anything!
if expr.op.__class__.__name__ == 'UAdd':
return ssa_val
prim = prims.find_ast_op(expr.op)
return syntax.PrimCall(prim, [ssa_val])
def visit_BinOp(self, expr):
ssa_left = self.visit(expr.left)
ssa_right = self.visit(expr.right)
prim = prims.find_ast_op(expr.op)
return syntax.PrimCall(prim, [ssa_left, ssa_right])
def visit_BoolOp(self, expr):
values = map(self.visit, expr.values)
prim = prims.find_ast_op(expr.op)
# Python, strangely, allows more than two arguments to
# Boolean operators
result = values[0]
for v in values[1:]:
result = syntax.PrimCall(prim, [result, v])
return result
def visit_Compare(self, expr):
lhs = self.visit(expr.left)
assert len(expr.ops) == 1
prim = prims.find_ast_op(expr.ops[0])
assert len(expr.comparators) == 1
rhs = self.visit(expr.comparators[0])
return syntax.PrimCall(prim, [lhs, rhs])
def visit_Subscript(self, expr):
value = self.visit(expr.value)
index = self.visit(expr.slice)
return syntax.Index(value, index)
def generic_visit(self, expr):
raise UnsupportedSyntax(expr,
function_name = self.function_name,
filename = self.filename)
def translate_builtin_call(self, value, positional, keywords_dict):
from ..mappings import function_mappings
if value is sum:
return mk_reduce_call(prim_wrapper(prims.add), positional, zero_i64)
elif value is max:
if len(positional) == 1:
return mk_reduce_call(prim_wrapper(prims.maximum), positional)
else:
assert len(positional) == 2
return syntax.PrimCall(prims.maximum, positional)
elif value is min:
if len(positional) == 1:
return mk_reduce_call(prim_wrapper(prims.minimum), positional)
else:
assert len(positional) == 2
return syntax.PrimCall(prims.minimum, positional)
elif value is map:
assert len(keywords_dict) == 0
assert len(positional) > 1
axis = keywords_dict.get("axis", None)
return Map(fn = positional[0], args = positional[1:], axis = axis)
elif value in function_mappings:
parakeet_equiv = function_mappings[value]
if isinstance(parakeet_equiv, macro):
return parakeet_equiv.transform(positional, keywords_dict)
fn = value_to_syntax(value)
return syntax.Call(fn, ActualArgs(positional, keywords_dict))
def visit(self, node):
res = ast.NodeVisitor.visit(self, node)
return res
def translate_value_call(self, value, positional, keywords_dict= {}, starargs_expr = None):
from ..mappings import function_mappings
if value in function_mappings:
value = function_mappings[value]
if isinstance(value, macro):
return value.transform(positional, keywords_dict)
elif is_user_function(value):
return syntax.Call(translate_function_value(value),
ActualArgs(positional, keywords_dict, starargs_expr))
else:
return self.translate_builtin_call(value, positional, keywords_dict)
def visit_Call(self, expr):
"""
TODO:
The logic here is broken and haphazard, eventually try to handle nested
scopes correctly, along with globals, cell refs, etc..
"""
fn, args, keywords_list, starargs, kwargs = \
expr.func, expr.args, expr.keywords, expr.starargs, expr.kwargs
assert kwargs is None, "Dictionary of keyword args not supported"
positional = self.visit_list(args)
keywords_dict = {}
for kwd in keywords_list:
keywords_dict[kwd.arg] = self.visit(kwd.value)
if starargs:
starargs_expr = self.visit(starargs)
else:
starargs_expr = None
def is_attr_chain(expr):
return isinstance(expr, ast.Name) or \
(isinstance(expr, ast.Attribute) and is_attr_chain(expr.value))
def extract_attr_chain(expr):
if isinstance(expr, ast.Name):
return [expr.id]
else:
base = extract_attr_chain(expr.value)
base.append(expr.attr)
return base
def lookup_attr_chain(names):
value = self.lookup_global(names[0])
for name in names[1:]:
if hasattr(value, name):
value = getattr(value, name)
else:
try:
value = value[name]
except:
assert False, "Couldn't find global name %s" % ('.'.join(names))
return value
if is_attr_chain(fn):
names = extract_attr_chain(fn)
if self.is_global(names):
return self.translate_value_call(lookup_attr_chain(names),
positional, keywords_dict, starargs_expr)
fn_node = self.visit(fn)
if isinstance(fn_node, syntax.Expr):
actuals = ActualArgs(positional, keywords_dict, starargs_expr)
return syntax.Call(fn_node, actuals)
else:
assert isinstance(fn_node, ExternalValue)
return self.translate_value_call(fn_node.value,
positional, keywords_dict, starargs_expr)
def visit_List(self, expr):
return syntax.Array(self.visit_list(expr.elts))
def visit_Expr(self, expr):
# dummy assignment to allow for side effects on RHS
lhs = self.fresh_var("dummy")
if isinstance(expr.value, ast.Str):
return syntax.Assign(lhs, zero_i64)
# return syntax.Comment(expr.value.s.strip().replace('\n', ''))
else:
rhs = self.visit(expr.value)
return syntax.Assign(lhs, rhs)
def visit_GeneratorExp(self, expr):
return self.visit_ListComp(expr)
def visit_ListComp(self, expr):
gens = expr.generators
assert len(gens) == 1
gen = gens[0]
target = gen.target
if target.__class__ is ast.Name:
arg_vars = [target]
else:
assert target.__class__ is ast.Tuple and all(e.__class__ is ast.Name for e in target.elts),\
"Expected comprehension target to be variable or tuple of variables, got %s" % ast.dump(target)
arg_vars = [ast.Tuple(elts = target.elts)]
# build a lambda as a Python ast representing
# what we do to each element
args = ast.arguments(args = arg_vars,
vararg = None,
kwarg = None,
defaults = ())
fn = translate_function_ast(name = "comprehension_map",
args = args,
body = [ast.Return(expr.elt)],
parent = self)
seq = self.visit(gen.iter)
ifs = gen.ifs
assert len(ifs) == 0, "Parakeet: Conditions in array comprehensions not yet supported"
return Map(fn = fn, args=(seq,), axis = zero_i64)
def visit_Attribute(self, expr):
# TODO:
# Recursive lookup to see if:
# (1) base object is local, if so-- create chain of attributes
# (2) base object is global but an adverb primitive-- use it locally
# without adding it to nonlocals
# (3) not local at all-- in which case, add the whole chain of strings
# to nonlocals
#
# AN IDEA:
# Allow external values to be brought into the syntax tree as
# a designated ExternalValue node
# and then here check if the LHS is an ExternalValue and if so,
# pull out the value. If it's a constant, then make it into syntax,
# if it's a function, then parse it, else raise an error.
#
from ..mappings import property_mappings, method_mappings
value = self.visit(expr.value)
attr = expr.attr
if isinstance(value, ExternalValue):
value = value.value
value = getattr(value, attr)
if is_static_value(value):
return value_to_syntax(value)
else:
return ExternalValue(value)
elif attr in property_mappings:
fn = property_mappings[attr]
if isinstance(fn, macro):
return fn.transform( [value] )
else:
return syntax.Call(translate_function_value(fn),
ActualArgs(positional = (value,)))
elif attr in method_mappings:
fn_python = method_mappings[attr]
fn_syntax = translate_function_value(fn_python)
return syntax.Closure(fn_syntax, args=(value,))
else:
assert False, "Attribute %s not supported" % attr
# return syntax.Attribute(value, expr.attr)
def visit_Num(self, expr):
return syntax.Const(expr.n)
def visit_Tuple(self, expr):
return syntax.Tuple(self.visit_list(expr.elts))
def visit_IfExp(self, expr):
temp1, temp2, result = self.fresh_vars(["if_true", "if_false", "if_result"])
cond = self.visit(expr.test)
true_block = [Assign(temp1, self.visit(expr.body))]
false_block = [Assign(temp2, self.visit(expr.orelse))]
merge = {result.name : (temp1, temp2)}
if_stmt = If(cond, true_block, false_block, merge)
self.current_block().append(if_stmt)
return result
def visit_lhs(self, lhs):
if isinstance(lhs, ast.Name):
return self.fresh_var(lhs.id)
elif isinstance(lhs, ast.Tuple):
return syntax.Tuple( map(self.visit_lhs, lhs.elts))
else:
# in case of slicing or attributes
res = self.visit(lhs)
return res
def visit_Assign(self, stmt):
# important to evaluate RHS before LHS for statements like 'x = x + 1'
ssa_rhs = self.visit(stmt.value)
ssa_lhs = self.visit_lhs(stmt.targets[0])
return Assign(ssa_lhs, ssa_rhs)
def visit_AugAssign(self, stmt):
ssa_incr = self.visit(stmt.value)
ssa_old_value = self.visit(stmt.target)
ssa_new_value = self.visit_lhs(stmt.target)
prim = prims.find_ast_op(stmt.op)
return Assign(ssa_new_value, PrimCall(prim, [ssa_old_value, ssa_incr]))
def visit_Return(self, stmt):
return syntax.Return(self.visit(stmt.value))
def visit_If(self, stmt):
cond = self.visit(stmt.test)
true_scope, true_block = self.visit_block(stmt.body)
false_scope, false_block = self.visit_block(stmt.orelse)
merge = self.create_phi_nodes(true_scope, false_scope)
return syntax.If(cond, true_block, false_block, merge)
def visit_loop_body(self, body, *exprs):
merge = {}
substitutions = {}
curr_scope = self.current_scope()
exprs = [self.visit(expr) for expr in exprs]
scope_after, body = self.visit_block(body)
for (k, name_after) in scope_after.iteritems():
if k in self.scopes:
name_before = self.scopes[k]
new_name = names.fresh(k + "_loop")
merge[new_name] = (Var(name_before), Var(name_after))
substitutions[name_before] = new_name
curr_scope[k] = new_name
exprs = [subst_expr(expr, substitutions) for expr in exprs]
body = subst_stmt_list(body, substitutions)
return body, merge, exprs
def visit_While(self, stmt):
assert not stmt.orelse
body, merge, (cond,) = self.visit_loop_body(stmt.body, stmt.test)
return syntax.While(cond, body, merge)
def visit_For(self, stmt):
assert not stmt.orelse
var = self.visit_lhs(stmt.target)
assert isinstance(var, Var)
seq = self.visit(stmt.iter)
body, merge, _ = self.visit_loop_body(stmt.body)
if isinstance(seq, syntax.Range):
return ForLoop(var, seq.start, seq.stop, seq.step, body, merge)
else:
seq_name = self.fresh_name("seq")
seq_var = Var(seq_name)
self.current_block().append(Assign(seq_var, seq))
len_fn = translate_function_value(len)
n = syntax.Call(len_fn, ActualArgs([seq_var]))
start = zero_i64
step = one_i64
loop_counter_name = self.fresh_name('loop_counter')
loop_var = Var(loop_counter_name)
body = [Assign(var, syntax.Index(seq_var, loop_var))] + body
return ForLoop(loop_var, start, n, step, body, merge)
def visit_block(self, stmts):
self.push()
curr_block = self.current_block()
for stmt in stmts:
parakeet_stmt = self.visit(stmt)
curr_block.append(parakeet_stmt)
return self.pop()
def visit_FunctionDef(self, node):
"""
Translate a nested function
"""
fundef = translate_function_ast(node.name, node.args, node.body, parent = self)
local_var = self.fresh_var(node.name)
return Assign(local_var, fundef)
def visit_Lambda(self, node):
return translate_function_ast("lambda", node.args, [ast.Return(node.body)], parent = self)