def MaybeAddSingleExitBlock(self, g: nx.MultiDiGraph) -> None:
"""Add a magic exit block to unite the exit statements of a CFG.
Args:
g: The graph to add the exit block to.
"""
exit_blocks = list(nx_utils.ExitBlockIterator(g))
if not exit_blocks:
raise ValueError("No exit blocks found in graph!")
if (
self.only_add_entry_and_exit_blocks_if_required and len(exit_blocks) == 1
):
exit_block = exit_blocks[0][0]
else:
exit_block = f"{g.name}_exit"
g.add_node(
exit_block, name=exit_block, type="magic", x=self.dictionary["!MAGIC"]
)
# Connect exit blocks.
for node, data in exit_blocks:
g.add_edge(node, exit_block, flow="control")
# Add a dataflow edge out, if there is one.
for src, dst, data in nx_utils.DataFlowEdgeIterator(g):
if dst == node:
g.add_edge(node, exit_block, flow="data")
break
g.exit_block = exit_block
def MaybeAddSingleExitBlock(self, g: nx.MultiDiGraph) -> None:
"""Add a magic exit block to unite the exit statements of a CFG.
Args:
g: The graph to add the exit block to.
"""
exit_blocks = list(nx_utils.ExitBlockIterator(g))
if not exit_blocks:
raise ValueError("No exit blocks found in graph!")
if len(exit_blocks) == 1:
exit_block = exit_blocks[0][0]
else:
exit_block = f"{g.name}_exit"
g.add_node(
exit_block,
name=exit_block,
type=programl_pb2.Node.STATEMENT,
text="",
preprocessed_text="",
function=None,
x=[self.node_encoder.dictionary["!MAGIC"]],
y=[],
)
# Connect exit blocks.
for node, data in exit_blocks:
g.add_edge(node,
exit_block,
flow=programl_pb2.Edge.CONTROL,
position=0)
# Add a dataflow edge out, if there is one.
for src, dst, data in nx_utils.DataFlowEdgeIterator(g):
if dst == node:
g.add_edge(node,
exit_block,
flow=programl_pb2.Edge.DATA,
position=0)
break
g.graph["exit_block"] = exit_block
def test_DataFlowEdgeIterator(graph):
assert len(list(nx_utils.DataFlowEdgeIterator(graph))) == 2