def resolve_runtime_index(lval, index):
max_idx = lval.locals["size"]
return_expr = lval.locals["0"]
for hdr_idx in range(1, max_idx):
cond = index == hdr_idx
return_expr = handle_mux(cond, lval.locals[f"{hdr_idx}"], return_expr)
return return_expr
def eval_callable(self, ctx, merged_args, var_buffer):
# execute the action expression with the new environment
ctx.return_type = self.return_type
self.statements.eval(ctx)
return_expr = None
if len(ctx.return_exprs) == 1:
_, return_expr = ctx.return_exprs.pop()
elif len(ctx.return_exprs) > 1:
# the first condition is not needed since it is the default
_, return_expr = ctx.return_exprs.pop()
if isinstance(return_expr, StructInstance):
while ctx.return_exprs:
then_cond, then_expr = ctx.return_exprs.pop()
return_expr = handle_mux(then_cond, then_expr, return_expr)
else:
while ctx.return_exprs:
then_cond, then_expr = ctx.return_exprs.pop()
return_expr = z3.If(then_cond, then_expr, return_expr)
return return_expr
def eval(self, p4_state):
cond = z3.simplify(p4_state.resolve_expr(self.cond))
# handle side effects for function and table calls
if cond == z3.BoolVal(False):
return p4_state.resolve_expr(self.else_val)
if cond == z3.BoolVal(True):
return p4_state.resolve_expr(self.then_val)
var_store, chain_copy = p4_state.checkpoint()
context = p4_state.current_context()
forward_cond_copy = context.tmp_forward_cond
context.tmp_forward_cond = z3.And(forward_cond_copy, cond)
then_expr = p4_state.resolve_expr(self.then_val)
then_vars = p4_state.get_attrs()
p4_state.restore(var_store, chain_copy)
context.tmp_forward_cond = forward_cond_copy
else_expr = p4_state.resolve_expr(self.else_val)
merge_attrs(p4_state, cond, then_vars)
return handle_mux(cond, then_expr, else_expr)