def decompose(self, pre, post, fail=False): v = self.get_callee() if not isinstance(v, Action): return [] actual_params = self.args[0].args actual_returns = self.args[1:] vocab = list(symbols_asts(actual_params + actual_returns)) formals = v.formal_params + v.formal_returns premap, pre = hide_state_map(formals, pre) postmap, post = hide_state_map(formals, post) actual_params = [rename_ast(p, premap) for p in actual_params] actual_returns = [rename_ast(p, postmap) for p in actual_returns] pre = constrain_state( pre, And(* [Equals(x, y) for x, y in zip(actual_params, v.formal_params)])) if not fail: post = constrain_state( post, And(*[ Equals(x, y) for x, y in zip(actual_returns, v.formal_returns) ])) ren = dict((x, x.prefix('__hide:')) for x in actual_returns) post = (post[0], rename_clauses(post[1], ren), post[2]) callee = v.clone(v.args) # drop the formals res = [(pre, [callee], post)] print "decompose call:" print "pre = {}".format(pre) print "callee = {}".format(callee) print "post = {}".format(post) return res
def show_sym(v,decd,val): if all(x in inv_env or not my_is_skolem(x) and not tr.is_new(x) and x not in env for x in ilu.used_symbols_ast(decd)): expr = ilu.rename_ast(decd,inv_env) if not (expr in self.current and self.current[expr] == val): print ' {} = {}'.format(expr,val) self.current[expr] = val
def handle(self,action,env): def my_is_skolem(x): return tr.is_skolem(x) and x not in self.cnsts def show_sym(v,decd,val): if all(x in inv_env or not my_is_skolem(x) and not tr.is_new(x) and x not in env for x in ilu.used_symbols_ast(decd)): expr = ilu.rename_ast(decd,inv_env) if not (expr in self.current and self.current[expr] == val): print ' {} = {}'.format(expr,val) self.current[expr] = val if hasattr(action,'lineno'): # print ' env: {}'.format('{'+','.join('{}:{}'.format(x,y) for x,y in env.iteritems())+'}') inv_env = dict((y,x) for x,y in env.iteritems()) for v in self.aiger.inputs: if v in self.decoder: show_sym(v,self.decoder[v],self.aiger.get_sym(v)) rn = dict((x,tr.new(x)) for x in self.stvarset) for v in self.aiger.latches: if v in self.decoder: decd = self.decoder[v] show_sym(v,ilu.rename_ast(decd,rn),self.aiger.get_next_sym(v)) print ' {}{}'.format(action.lineno,action)
def decompose(self, pre, post): v = self.get_callee() if not isinstance(v, Action): return [] actual_params = self.args[0].args actual_returns = self.args[1:] vocab = list(symbols_asts(actual_params + actual_returns)) formals = v.formal_params + v.formal_returns premap, pre = hide_state_map(formals, pre) postmap, post = hide_state_map(formals, post) actual_params = [rename_ast(p, premap) for p in actual_params] actual_returns = [rename_ast(p, postmap) for p in actual_returns] pre = constrain_state(pre, And(*[Equals(x, y) for x, y in zip(actual_params, v.formal_params)])) post = constrain_state(post, And(*[Equals(x, y) for x, y in zip(actual_returns, v.formal_returns)])) ren = dict((x, x.prefix("__hide:")) for x in actual_returns) post = (post[0], rename_clauses(post[1], ren), post[2]) callee = v.clone(v.args) # drop the formals return [(pre, [callee], post)]
def prev_expr(stvarset,expr,sort_constants): if any(sym in stvarset or tr.is_skolem(sym) and not sym in sort_constants[sym.sort] for sym in ilu.symbols_ast(expr)): return None news = [sym for sym in ilu.used_symbols_ast(expr) if tr.is_new(sym)] if news: rn = dict((sym,tr.new_of(sym)) for sym in news) return ilu.rename_ast(expr,rn) return None
def new_state_pairs(self, sym_pairs, env): eqns = [] for sym, renamed_sym in sym_pairs: rmap = {renamed_sym: sym} # TODO: what if the renamed symbol is not in the model? for fmla in self.get_sym_eqs(renamed_sym): rfmla = lut.rename_ast(fmla, rmap) eqns.append(rfmla) self.add_state(eqns)
def show_sym(self, sym, renamed_sym): if sym in self.renaming and self.renaming[sym] == renamed_sym: return self.renaming[sym] = renamed_sym rmap = {renamed_sym: sym} # TODO: what if the renamed symbol is not in the model? for fmla in self.eqs[renamed_sym]: rfmla = lut.rename_ast(fmla, rmap) lhs, rhs = rfmla.args if lhs in self.current and self.current[lhs] == rhs: continue self.current[lhs] = rhs print ' {}'.format(rfmla)
def action_def_to_str(name,action): res = "action {}".format(name) if action.formal_params: res += params_to_str(action.formal_params) if action.formal_returns: res += ' returns' + params_to_str(action.formal_returns) res += ' = ' subs = dict() for s in action.formal_params + action.formal_returns: if s.name.startswith('fml:'): subs[s] = s.drop_prefix('fml:') action = rename_ast(action,subs) if isinstance(action,Sequence): res += str(action) else: res += '{' + str(action) + '}' return res
def new_state_pairs(self, sym_pairs, env): eqns = [] for sym, renamed_sym in sym_pairs: rmap = {renamed_sym: sym} # TODO: what if the renamed symbol is not in the model? for fmla in self.eqs[renamed_sym]: rfmla = lut.rename_ast(fmla, rmap) eqns.append(rfmla) clauses = lut.Clauses(eqns) state = self.domain.new_state(clauses) state.universe = self.model.universes(numerals=True) if self.last_action is not None: expr = itp.action_app(self.last_action, self.states[-1]) if self.returned is not None: expr.subgraph = self.returned self.returned = None self.last_action = None self.add(state, expr) else: self.add(state)
def to_aiger(mod,ext_act): erf = il.Symbol('err_flag',il.find_sort('bool')) errconds = [] add_err_flag_mod(mod,erf,errconds) # we use a special state variable __init to indicate the initial state ext_acts = [mod.actions[x] for x in sorted(mod.public_actions)] ext_act = ia.EnvAction(*ext_acts) init_var = il.Symbol('__init',il.find_sort('bool')) init = add_err_flag(ia.Sequence(*([a for n,a in mod.initializers]+[ia.AssignAction(init_var,il.And())])),erf,errconds) action = ia.Sequence(ia.AssignAction(erf,il.Or()),ia.IfAction(init_var,ext_act,init)) # get the invariant to be proved, replacing free variables with # skolems. First, we apply any proof tactics. pc = ivy_proof.ProofChecker(mod.axioms,mod.definitions,mod.schemata) pmap = dict((lf.id,p) for lf,p in mod.proofs) conjs = [] for lf in mod.labeled_conjs: if lf.id in pmap: proof = pmap[lf.id] subgoals = pc.admit_proposition(lf,proof) conjs.extend(subgoals) else: conjs.append(lf) invariant = il.And(*[il.drop_universals(lf.formula) for lf in conjs]) # iu.dbg('invariant') skolemizer = lambda v: ilu.var_to_skolem('__',il.Variable(v.rep,v.sort)) vs = ilu.used_variables_in_order_ast(invariant) sksubs = dict((v.rep,skolemizer(v)) for v in vs) invariant = ilu.substitute_ast(invariant,sksubs) invar_syms = ilu.used_symbols_ast(invariant) # compute the transition relation stvars,trans,error = action.update(mod,None) # print 'action : {}'.format(action) # print 'annotation: {}'.format(trans.annot) annot = trans.annot # match_annotation(action,annot,MatchHandler()) indhyps = [il.close_formula(il.Implies(init_var,lf.formula)) for lf in mod.labeled_conjs] # trans = ilu.and_clauses(trans,indhyps) # save the original symbols for trace orig_syms = ilu.used_symbols_clauses(trans) orig_syms.update(ilu.used_symbols_ast(invariant)) # TODO: get the axioms (or maybe only the ground ones?) # axioms = mod.background_theory() # rn = dict((sym,tr.new(sym)) for sym in stvars) # next_axioms = ilu.rename_clauses(axioms,rn) # return ilu.and_clauses(axioms,next_axioms) funs = set() for df in trans.defs: funs.update(ilu.used_symbols_ast(df.args[1])) for fmla in trans.fmlas: funs.update(ilu.used_symbols_ast(fmla)) # funs = ilu.used_symbols_clauses(trans) funs.update(ilu.used_symbols_ast(invariant)) funs = set(sym for sym in funs if il.is_function_sort(sym.sort)) iu.dbg('[str(fun) for fun in funs]') # Propositionally abstract # step 1: get rid of definitions of non-finite symbols by turning # them into constraints new_defs = [] new_fmlas = [] for df in trans.defs: if len(df.args[0].args) == 0 and is_finite_sort(df.args[0].sort): new_defs.append(df) else: fmla = df.to_constraint() new_fmlas.append(fmla) trans = ilu.Clauses(new_fmlas+trans.fmlas,new_defs) # step 2: get rid of ite's over non-finite sorts, by introducing constraints cnsts = [] new_defs = [elim_ite(df,cnsts) for df in trans.defs] new_fmlas = [elim_ite(fmla,cnsts) for fmla in trans.fmlas] trans = ilu.Clauses(new_fmlas+cnsts,new_defs) # step 3: eliminate quantfiers using finite instantiations from_asserts = il.And(*[il.Equals(x,x) for x in ilu.used_symbols_ast(il.And(*errconds)) if tr.is_skolem(x) and not il.is_function_sort(x.sort)]) iu.dbg('from_asserts') invar_syms.update(ilu.used_symbols_ast(from_asserts)) sort_constants = mine_constants(mod,trans,il.And(invariant,from_asserts)) sort_constants2 = mine_constants2(mod,trans,invariant) print '\ninstantiations:' trans,invariant = Qelim(sort_constants,sort_constants2)(trans,invariant,indhyps) # print 'after qe:' # print 'trans: {}'.format(trans) # print 'invariant: {}'.format(invariant) # step 4: instantiate the axioms using patterns # We have to condition both the transition relation and the # invariant on the axioms, so we define a boolean symbol '__axioms' # to represent the axioms. axs = instantiate_axioms(mod,stvars,trans,invariant,sort_constants,funs) ax_conj = il.And(*axs) ax_var = il.Symbol('__axioms',ax_conj.sort) ax_def = il.Definition(ax_var,ax_conj) invariant = il.Implies(ax_var,invariant) trans = ilu.Clauses(trans.fmlas+[ax_var],trans.defs+[ax_def]) # step 5: eliminate all non-propositional atoms by replacing with fresh booleans # An atom with next-state symbols is converted to a next-state symbol if possible stvarset = set(stvars) prop_abs = dict() # map from atoms to proposition variables global prop_abs_ctr # sigh -- python lameness prop_abs_ctr = 0 # counter for fresh symbols new_stvars = [] # list of fresh symbols # get the propositional abstraction of an atom def new_prop(expr): res = prop_abs.get(expr,None) if res is None: prev = prev_expr(stvarset,expr,sort_constants) if prev is not None: # print 'stvar: old: {} new: {}'.format(prev,expr) pva = new_prop(prev) res = tr.new(pva) new_stvars.append(pva) prop_abs[expr] = res # prevent adding this again to new_stvars else: global prop_abs_ctr res = il.Symbol('__abs[{}]'.format(prop_abs_ctr),expr.sort) # print '{} = {}'.format(res,expr) prop_abs[expr] = res prop_abs_ctr += 1 return res # propositionally abstract an expression global mk_prop_fmlas mk_prop_fmlas = [] def mk_prop_abs(expr): if il.is_quantifier(expr) or len(expr.args) > 0 and any(not is_finite_sort(a.sort) for a in expr.args): return new_prop(expr) return expr.clone(map(mk_prop_abs,expr.args)) # apply propositional abstraction to the transition relation new_defs = map(mk_prop_abs,trans.defs) new_fmlas = [mk_prop_abs(il.close_formula(fmla)) for fmla in trans.fmlas] # find any immutable abstract variables, and give them a next definition def my_is_skolem(x): res = tr.is_skolem(x) and x not in invar_syms return res def is_immutable_expr(expr): res = not any(my_is_skolem(sym) or tr.is_new(sym) or sym in stvarset for sym in ilu.used_symbols_ast(expr)) return res for expr,v in prop_abs.iteritems(): if is_immutable_expr(expr): new_stvars.append(v) print 'new state: {}'.format(expr) new_defs.append(il.Definition(tr.new(v),v)) trans = ilu.Clauses(new_fmlas+mk_prop_fmlas,new_defs) # apply propositional abstraction to the invariant invariant = mk_prop_abs(invariant) # create next-state symbols for atoms in the invariant (is this needed?) rn = dict((sym,tr.new(sym)) for sym in stvars) mk_prop_abs(ilu.rename_ast(invariant,rn)) # this is to pick up state variables from invariant # update the state variables by removing the non-finite ones and adding the fresh state booleans stvars = [sym for sym in stvars if is_finite_sort(sym.sort)] + new_stvars # iu.dbg('trans') # iu.dbg('stvars') # iu.dbg('invariant') # exit(0) # For each state var, create a variable that corresponds to the input of its latch # Also, havoc all the state bits except the init flag at the initial time. This # is needed because in aiger, all latches start at 0! def fix(v): return v.prefix('nondet') def curval(v): return v.prefix('curval') def initchoice(v): return v.prefix('initchoice') stvars_fix_map = dict((tr.new(v),fix(v)) for v in stvars) stvars_fix_map.update((v,curval(v)) for v in stvars if v != init_var) trans = ilu.rename_clauses(trans,stvars_fix_map) # iu.dbg('trans') new_defs = trans.defs + [il.Definition(ilu.sym_inst(tr.new(v)),ilu.sym_inst(fix(v))) for v in stvars] new_defs.extend(il.Definition(curval(v),il.Ite(init_var,v,initchoice(v))) for v in stvars if v != init_var) trans = ilu.Clauses(trans.fmlas,new_defs) # Turn the transition constraint into a definition cnst_var = il.Symbol('__cnst',il.find_sort('bool')) new_defs = list(trans.defs) new_defs.append(il.Definition(tr.new(cnst_var),fix(cnst_var))) new_defs.append(il.Definition(fix(cnst_var),il.Or(cnst_var,il.Not(il.And(*trans.fmlas))))) stvars.append(cnst_var) trans = ilu.Clauses([],new_defs) # Input are all the non-defined symbols. Output indicates invariant is false. # iu.dbg('trans') def_set = set(df.defines() for df in trans.defs) def_set.update(stvars) # iu.dbg('def_set') used = ilu.used_symbols_clauses(trans) used.update(ilu.symbols_ast(invariant)) inputs = [sym for sym in used if sym not in def_set and not il.is_interpreted_symbol(sym)] fail = il.Symbol('__fail',il.find_sort('bool')) outputs = [fail] # iu.dbg('trans') # make an aiger aiger = Encoder(inputs,stvars,outputs) comb_defs = [df for df in trans.defs if not tr.is_new(df.defines())] invar_fail = il.Symbol('invar__fail',il.find_sort('bool')) # make a name for invariant fail cond comb_defs.append(il.Definition(invar_fail,il.Not(invariant))) aiger.deflist(comb_defs) for df in trans.defs: if tr.is_new(df.defines()): aiger.set(tr.new_of(df.defines()),aiger.eval(df.args[1])) miter = il.And(init_var,il.Not(cnst_var),il.Or(invar_fail,il.And(fix(erf),il.Not(fix(cnst_var))))) aiger.set(fail,aiger.eval(miter)) # aiger.sub.debug() # make a decoder for the abstract propositions decoder = dict((y,x) for x,y in prop_abs.iteritems()) for sym in aiger.inputs + aiger.latches: if sym not in decoder and sym in orig_syms: decoder[sym] = sym cnsts = set(sym for syms in sort_constants.values() for sym in syms) return aiger,decoder,annot,cnsts,action,stvarset