def enter_blocks (self, blocks):
super(ControlFlowBuilder, self).enter_blocks(blocks)
self.blocks = blocks
self.block_list = list(blocks.keys())
self.block_list.sort()
self.cfg = ControlFlowGraph()
self.loop_stack = []
for block in self.block_list:
self.cfg.add_block(block, blocks[block])
def enter_flow_object(self, flow):
super(ControlFlowBuilder, self).enter_flow_object(flow)
self.flow = flow
self.cfg = ControlFlowGraph()
for block in flow.keys():
self.cfg.add_block(block, flow[block])
class ControlFlowBuilder(BenignBytecodeVisitorMixin, BytecodeFlowVisitor):
'''Visitor responsible for traversing a bytecode flow object and
building a control flow graph (CFG).
The primary purpose of this transformation is to create a CFG,
which is used by later transformers for dataflow analysis.
'''
def visit(self, flow, nargs=0, *args, **kws):
'''Given a bytecode flow, and an optional number of arguments,
return a :py:class:`llpython.control_flow.ControlFlowGraph`
instance describing the full control flow of the bytecode
flow.'''
self.nargs = nargs
ret_val = super(ControlFlowBuilder, self).visit(flow, *args, **kws)
del self.nargs
return ret_val
def enter_flow_object(self, flow):
super(ControlFlowBuilder, self).enter_flow_object(flow)
self.flow = flow
self.cfg = ControlFlowGraph()
for block in flow.keys():
self.cfg.add_block(block, flow[block])
def exit_flow_object(self, flow):
super(ControlFlowBuilder, self).exit_flow_object(flow)
assert self.flow == flow
self.cfg.compute_dataflow()
self.cfg.update_for_ssa()
ret_val = self.cfg
del self.cfg
del self.flow
return ret_val
def enter_block(self, block):
self.block = block
assert block in self.cfg.blocks
if block == 0:
for local_index in range(self.nargs):
self.op_STORE_FAST(0, opcode.opmap['STORE_FAST'], local_index)
return True
def _get_next_block(self, block):
return self.block_list[self.block_list.index(block) + 1]
def exit_block(self, block):
assert block == self.block
del self.block
i, op, opname, arg, args = self.flow[block][-1]
if op in opcode.hasjabs:
self.cfg.add_edge(block, arg)
elif op in opcode.hasjrel:
self.cfg.add_edge(block, i + arg + 3)
elif opname == 'BREAK_LOOP':
self.cfg.add_edge(block, arg)
elif opname != 'RETURN_VALUE':
self.cfg.add_edge(block, self._get_next_block(block))
if op in opcode_util.hascbranch:
self.cfg.add_edge(block, self._get_next_block(block))
def op_LOAD_FAST(self, i, op, arg, *args, **kws):
self.cfg.blocks_reads[self.block].add(arg)
return super(ControlFlowBuilder,
self).op_LOAD_FAST(i, op, arg, *args, **kws)
def op_STORE_FAST(self, i, op, arg, *args, **kws):
self.cfg.writes_local(self.block, i, arg)
return super(ControlFlowBuilder,
self).op_STORE_FAST(i, op, arg, *args, **kws)
def enter_flow_object (self, flow):
super(ControlFlowBuilder, self).enter_flow_object(flow)
self.flow = flow
self.cfg = ControlFlowGraph()
for block in flow.keys():
self.cfg.add_block(block, flow[block])
class ControlFlowBuilder (BenignBytecodeVisitorMixin, BytecodeFlowVisitor):
'''Visitor responsible for traversing a bytecode flow object and
building a control flow graph (CFG).
The primary purpose of this transformation is to create a CFG,
which is used by later transformers for dataflow analysis.
'''
def visit (self, flow, nargs = 0, *args, **kws):
'''Given a bytecode flow, and an optional number of arguments,
return a :py:class:`llpython.control_flow.ControlFlowGraph`
instance describing the full control flow of the bytecode
flow.'''
self.nargs = nargs
ret_val = super(ControlFlowBuilder, self).visit(flow, *args, **kws)
del self.nargs
return ret_val
def enter_flow_object (self, flow):
super(ControlFlowBuilder, self).enter_flow_object(flow)
self.flow = flow
self.cfg = ControlFlowGraph()
for block in flow.keys():
self.cfg.add_block(block, flow[block])
def exit_flow_object (self, flow):
super(ControlFlowBuilder, self).exit_flow_object(flow)
assert self.flow == flow
self.cfg.compute_dataflow()
self.cfg.update_for_ssa()
ret_val = self.cfg
del self.cfg
del self.flow
return ret_val
def enter_block (self, block):
self.block = block
assert block in self.cfg.blocks
if block == 0:
for local_index in range(self.nargs):
self.op_STORE_FAST(0, opcode.opmap['STORE_FAST'], local_index)
return True
def _get_next_block (self, block):
return self.block_list[self.block_list.index(block) + 1]
def exit_block (self, block):
assert block == self.block
del self.block
i, op, opname, arg, args = self.flow[block][-1]
if op in opcode.hasjabs:
self.cfg.add_edge(block, arg)
elif op in opcode.hasjrel:
self.cfg.add_edge(block, i + arg + 3)
elif opname == 'BREAK_LOOP':
self.cfg.add_edge(block, arg)
elif opname != 'RETURN_VALUE':
self.cfg.add_edge(block, self._get_next_block(block))
if op in opcode_util.hascbranch:
self.cfg.add_edge(block, self._get_next_block(block))
def op_LOAD_FAST (self, i, op, arg, *args, **kws):
self.cfg.blocks_reads[self.block].add(arg)
return super(ControlFlowBuilder, self).op_LOAD_FAST(i, op, arg, *args,
**kws)
def op_STORE_FAST (self, i, op, arg, *args, **kws):
self.cfg.writes_local(self.block, i, arg)
return super(ControlFlowBuilder, self).op_STORE_FAST(i, op, arg, *args,
**kws)