speed up flow control implementation by compiling it

Cython/Compiler/FlowControl.pxd

+cimport cython
+
+cdef class ControlBlock:
+     cdef public set children
+     cdef public set parents
+     cdef public set positions
+     cdef public list stats
+     cdef public dict gen
+     cdef public set bounded
+     cdef public dict input
+     cdef public dict output
+
+     cpdef bint empty(self)
+     cpdef detach(self)
+     cpdef add_child(self, block)
+
+cdef class ExitBlock(ControlBlock):
+     cpdef bint empty(self)
+
+cdef class ControlFlow:
+     cdef public set blocks
+     cdef public set entries
+     cdef public list loops
+     cdef public list exceptions
+
+     cdef public ControlBlock entry_point
+     cdef public ExitBlock exit_point
+     cdef public ControlBlock block
+
+     cpdef newblock(self, parent=*)
+     cpdef nextblock(self, parent=*)
+     cpdef bint is_tracked(self, entry)
+     cpdef mark_position(self, node)
+     cpdef mark_assignment(self, lhs, rhs, entry=*)
+     cpdef mark_argument(self, lhs, rhs, entry)
+     cpdef mark_deletion(self, node, entry)
+     cpdef mark_reference(self, node, entry)
+     cpdef normalize(self)
+
+cdef class Uninitialized:
+     pass
+
+@cython.locals(dirty=bint, block=ControlBlock, parent=ControlBlock)
+cdef check_definitions(ControlFlow flow, dict compiler_directives)