/// add axioms stating that if two strings are equal then their hash codes are
/// equals
/// \par parameters: function application with a string argument
/// \return a integer expression corresponding to the hash code of the string
exprt string_constraint_generatort::add_axioms_for_hash_code(
const function_application_exprt &f)
{
string_exprt str=add_axioms_for_string_expr(args(f, 1)[0]);
typet return_type=f.type();
typet index_type=str.length().type();
// initialisation of the missing pool variable
std::map<irep_idt, string_exprt>::iterator it;
for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
if(hash.find(it->second)==hash.end())
hash[it->second]=fresh_symbol("hash", return_type);
// for each string s. either:
// c1: hash(str)=hash(s)
// c2: |str|!=|s|
// c3: (|str|==|s| &&exists i<|s|. s[i]!=str[i])
// WARNING: the specification may be incomplete
for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
{
symbol_exprt i=fresh_exist_index("index_hash", index_type);
equal_exprt c1(hash[it->second], hash[str]);
not_exprt c2(equal_exprt(it->second.length(), str.length()));
and_exprt c3(
equal_exprt(it->second.length(), str.length()),
and_exprt(
not_exprt(equal_exprt(str[i], it->second[i])),
and_exprt(
str.axiom_for_is_strictly_longer_than(i),
axiom_for_is_positive_index(i))));
axioms.push_back(or_exprt(c1, or_exprt(c2, c3)));
}
return hash[str];
}
/// add axioms stating that the return value for two equal string should be the
/// same
/// \par parameters: function application with one string argument
/// \return a string expression
symbol_exprt string_constraint_generatort::add_axioms_for_intern(
const function_application_exprt &f)
{
string_exprt str=add_axioms_for_string_expr(args(f, 1)[0]);
const typet &return_type=f.type();
typet index_type=str.length().type();
// initialisation of the missing pool variable
std::map<irep_idt, string_exprt>::iterator it;
for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
if(pool.find(it->second)==pool.end())
pool[it->second]=fresh_symbol("pool", return_type);
// intern(str)=s_0 || s_1 || ...
// for each string s.
// intern(str)=intern(s) || |str|!=|s|
// || (|str|==|s| &&exists i<|s|. s[i]!=str[i])
exprt disj=false_exprt();
for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
disj=or_exprt(
disj, equal_exprt(pool[str], symbol_exprt(it->first, return_type)));
axioms.push_back(disj);
// WARNING: the specification may be incomplete or incorrect
for(it=symbol_to_string.begin(); it!=symbol_to_string.end(); it++)
if(it->second!=str)
{
symbol_exprt i=fresh_exist_index("index_intern", index_type);
axioms.push_back(
or_exprt(
equal_exprt(pool[it->second], pool[str]),
or_exprt(
not_exprt(str.axiom_for_has_same_length_as(it->second)),
and_exprt(
str.axiom_for_has_same_length_as(it->second),
and_exprt(
not_exprt(equal_exprt(str[i], it->second[i])),
and_exprt(str.axiom_for_is_strictly_longer_than(i),
axiom_for_is_positive_index(i)))))));
}
return pool[str];
}
/// returns an expression which is true when the two given characters are equal
/// when ignoring case for ASCII
/// \par parameters: two character expressions and constant character
/// expressions
/// representing 'a', 'A' and 'Z'
/// \return a expression of Boolean type
exprt string_constraint_generatort::character_equals_ignore_case(
exprt char1, exprt char2, exprt char_a, exprt char_A, exprt char_Z)
{
and_exprt is_upper_case_1(
binary_relation_exprt(char_A, ID_le, char1),
binary_relation_exprt(char1, ID_le, char_Z));
and_exprt is_upper_case_2(
binary_relation_exprt(char_A, ID_le, char2),
binary_relation_exprt(char2, ID_le, char_Z));
// Three possibilities:
// p1 : char1=char2
// p2 : (is_up1&&'a'-'A'+char1=char2)
// p3 : (is_up2&&'a'-'A'+char2=char1)
equal_exprt p1(char1, char2);
minus_exprt diff=minus_exprt(char_a, char_A);
and_exprt p2(is_upper_case_1, equal_exprt(plus_exprt(diff, char1), char2));
and_exprt p3(is_upper_case_2, equal_exprt(plus_exprt(diff, char2), char1));
return or_exprt(or_exprt(p1, p2), p3);
}
/// add axioms corresponding to the String.equalsIgnoreCase java function
/// \par parameters: function application with two string arguments
/// \return a Boolean expression
exprt string_constraint_generatort::add_axioms_for_equals_ignore_case(
const function_application_exprt &f)
{
assert(f.type()==bool_typet() || f.type().id()==ID_c_bool);
symbol_exprt eq=fresh_boolean("equal_ignore_case");
typecast_exprt tc_eq(eq, f.type());
string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
string_exprt s2=add_axioms_for_string_expr(args(f, 2)[1]);
typet char_type=to_refined_string_type(s1.type()).get_char_type();
exprt char_a=constant_char('a', char_type);
exprt char_A=constant_char('A', char_type);
exprt char_Z=constant_char('Z', char_type);
typet index_type=s1.length().type();
// We add axioms:
// a1 : eq => |s1|=|s2|
// a2 : forall qvar, 0<=qvar<|s1|,
// eq => char_equal_ignore_case(s1[qvar],s2[qvar]);
// a3 : !eq => |s1|!=s2 || (0 <=witness<|s1| &&!char_equal_ignore_case)
implies_exprt a1(eq, s1.axiom_for_has_same_length_as(s2));
axioms.push_back(a1);
symbol_exprt qvar=fresh_univ_index("QA_equal_ignore_case", index_type);
exprt constr2=character_equals_ignore_case(
s1[qvar], s2[qvar], char_a, char_A, char_Z);
string_constraintt a2(qvar, s1.length(), eq, constr2);
axioms.push_back(a2);
symbol_exprt witness=fresh_exist_index(
"witness_unequal_ignore_case", index_type);
exprt zero=from_integer(0, witness.type());
and_exprt bound_witness(
binary_relation_exprt(witness, ID_lt, s1.length()),
binary_relation_exprt(witness, ID_ge, zero));
exprt witness_eq=character_equals_ignore_case(
s1[witness], s2[witness], char_a, char_A, char_Z);
not_exprt witness_diff(witness_eq);
implies_exprt a3(
not_exprt(eq),
or_exprt(
notequal_exprt(s1.length(), s2.length()),
and_exprt(bound_witness, witness_diff)));
axioms.push_back(a3);
return tc_eq;
}
guardt &operator |= (guardt &g1, const guardt &g2)
{
if(g2.is_false()) return g1;
if(g1.is_false()) { g1.guard_list=g2.guard_list; return g1; }
// find common prefix
guardt::guard_listt::iterator it1=g1.guard_list.begin();
guardt::guard_listt::const_iterator it2=g2.guard_list.begin();
while(it1!=g1.guard_list.end())
{
if(it2==g2.guard_list.end())
break;
if(*it1!=*it2)
break;
it1++;
it2++;
}
if(it2==g2.guard_list.end()) return g1;
// end of common prefix
exprt and_expr1, and_expr2;
and_expr1=g1.as_expr(it1);
and_expr2=g2.as_expr(it2);
g1.guard_list.erase(it1, g1.guard_list.end());
exprt tmp(and_expr2);
tmp.make_not();
if(tmp!=and_expr1)
{
if(and_expr1.is_true() || and_expr2.is_true())
{
}
else
g1.add(or_exprt(and_expr1, and_expr2));
}
return g1;
}
const exprt qbf_squolem_coret::f_get_dnf(WitnessStack *wsp)
{
Clause *p=wsp->posWits;
if(!p) return exprt(ID_false, typet(ID_bool));
exprt::operandst operands;
while(p!=NULL)
{
exprt cube=and_exprt();
for(unsigned i=0; i<p->size; i++)
{
const Literal &lit=p->literals[i];
exprt subf = f_get(literalt(var(lit), !isPositive(lit)));
if(find(cube.operands().begin(), cube.operands().end(), subf)==
cube.operands().end())
cube.move_to_operands(subf);
simplify_extractbits(cube);
}
if(cube.operands().empty())
cube=true_exprt();
else if(cube.operands().size()==1)
{
const exprt tmp=cube.op0();
cube=tmp;
}
#if 0
std::cout << "CUBE: " << cube << std::endl;
#endif
operands.push_back(cube);
p=p->next;
}
return or_exprt(operands);
}
const exprt qbf_squolem_coret::f_get_cnf(WitnessStack *wsp)
{
Clause *p=wsp->negWits;
if(!p) return exprt(ID_true, typet(ID_bool));
exprt::operandst operands;
while(p!=NULL)
{
exprt clause=or_exprt();
for(unsigned i=0; i<p->size; i++)
{
const Literal &lit=p->literals[i];
exprt subf = f_get(literalt(var(lit), isPositive(lit))); // negated!
if(find(clause.operands().begin(), clause.operands().end(), subf)==
clause.operands().end())
clause.move_to_operands(subf);
}
if(clause.operands().empty())
clause=false_exprt();
else if(clause.operands().size()==1)
{
const exprt tmp=clause.op0();
clause=tmp;
}
#if 0
std::cout << "CLAUSE: " << clause << std::endl;
#endif
operands.push_back(clause);
p=p->next;
}
return and_exprt(operands);
}
/// add axioms stating that the result is true exactly when the strings
/// represented by the arguments are equal
/// \par parameters: function application with two string arguments
/// \return a expression of Boolean type
exprt string_constraint_generatort::add_axioms_for_equals(
const function_application_exprt &f)
{
assert(f.type()==bool_typet() || f.type().id()==ID_c_bool);
symbol_exprt eq=fresh_boolean("equal");
typecast_exprt tc_eq(eq, f.type());
string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
string_exprt s2=add_axioms_for_string_expr(args(f, 2)[1]);
typet index_type=s1.length().type();
// We want to write:
// eq <=> (s1.length=s2.length &&forall i<s1.length. s1[i]=s2[i])
// We add axioms:
// a1 : eq => s1.length=s2.length
// a2 : forall i<s1.length. eq => s1[i]=s2[i]
// a3 : !eq => s1.length!=s2.length
// || (witness<s1.length &&s1[witness]!=s2[witness])
implies_exprt a1(eq, s1.axiom_for_has_same_length_as(s2));
axioms.push_back(a1);
symbol_exprt qvar=fresh_univ_index("QA_equal", index_type);
string_constraintt a2(qvar, s1.length(), eq, equal_exprt(s1[qvar], s2[qvar]));
axioms.push_back(a2);
symbol_exprt witness=fresh_exist_index("witness_unequal", index_type);
exprt zero=from_integer(0, index_type);
and_exprt bound_witness(
binary_relation_exprt(witness, ID_lt, s1.length()),
binary_relation_exprt(witness, ID_ge, zero));
and_exprt witnessing(bound_witness, notequal_exprt(s1[witness], s2[witness]));
implies_exprt a3(
not_exprt(eq),
or_exprt(notequal_exprt(s1.length(), s2.length()), witnessing));
axioms.push_back(a3);
return tc_eq;
}
/// add axioms corresponding to the String.compareTo java function
/// \par parameters: function application with two string arguments
/// \return a integer expression
exprt string_constraint_generatort::add_axioms_for_compare_to(
const function_application_exprt &f)
{
string_exprt s1=add_axioms_for_string_expr(args(f, 2)[0]);
string_exprt s2=add_axioms_for_string_expr(args(f, 2)[1]);
const typet &return_type=f.type();
symbol_exprt res=fresh_symbol("compare_to", return_type);
typet index_type=s1.length().type();
// In the lexicographic comparison, x is the first point where the two
// strings differ.
// We add axioms:
// a1 : res==0 => |s1|=|s2|
// a2 : forall i<|s1|. s1[i]==s2[i]
// a3 : exists x.
// res!=0 ==> x> 0 &&
// ((|s1| <= |s2| &&x<|s1|) || (|s1| >= |s2| &&x<|s2|)
// &&res=s1[x]-s2[x] )
// || cond2:
// (|s1|<|s2| &&x=|s1|) || (|s1| > |s2| &&x=|s2|) &&res=|s1|-|s2|)
// a4 : forall i<x. res!=0 => s1[i]=s2[i]
assert(return_type.id()==ID_signedbv);
equal_exprt res_null=equal_exprt(res, from_integer(0, return_type));
implies_exprt a1(res_null, s1.axiom_for_has_same_length_as(s2));
axioms.push_back(a1);
symbol_exprt i=fresh_univ_index("QA_compare_to", index_type);
string_constraintt a2(i, s1.length(), res_null, equal_exprt(s1[i], s2[i]));
axioms.push_back(a2);
symbol_exprt x=fresh_exist_index("index_compare_to", index_type);
equal_exprt ret_char_diff(
res,
minus_exprt(
typecast_exprt(s1[x], return_type),
typecast_exprt(s2[x], return_type)));
equal_exprt ret_length_diff(
res,
minus_exprt(
typecast_exprt(s1.length(), return_type),
typecast_exprt(s2.length(), return_type)));
or_exprt guard1(
and_exprt(s1.axiom_for_is_shorter_than(s2),
s1.axiom_for_is_strictly_longer_than(x)),
and_exprt(s1.axiom_for_is_longer_than(s2),
s2.axiom_for_is_strictly_longer_than(x)));
and_exprt cond1(ret_char_diff, guard1);
or_exprt guard2(
and_exprt(s2.axiom_for_is_strictly_longer_than(s1),
s1.axiom_for_has_length(x)),
and_exprt(s1.axiom_for_is_strictly_longer_than(s2),
s2.axiom_for_has_length(x)));
and_exprt cond2(ret_length_diff, guard2);
implies_exprt a3(
not_exprt(res_null),
and_exprt(
binary_relation_exprt(x, ID_ge, from_integer(0, return_type)),
or_exprt(cond1, cond2)));
axioms.push_back(a3);
string_constraintt a4(i, x, not_exprt(res_null), equal_exprt(s1[i], s2[i]));
axioms.push_back(a4);
return res;
}
codet java_bytecode_convertt::convert_instructions(
const instructionst &instructions,
const code_typet &method_type)
{
// Run a worklist algorithm, assuming that the bytecode has not
// been tampered with. See "Leroy, X. (2003). Java bytecode
// verification: algorithms and formalizations. Journal of Automated
// Reasoning, 30(3-4), 235-269." for a more complete treatment.
// first pass: get targets and map addresses to instructions
struct converted_instructiont
{
converted_instructiont(
const instructionst::const_iterator &it,
const codet &_code):source(it), code(_code), done(false)
{
}
instructionst::const_iterator source;
std::list<unsigned> successors;
std::set<unsigned> predecessors;
codet code;
stackt stack;
bool done;
};
typedef std::map<unsigned, converted_instructiont> address_mapt;
address_mapt address_map;
std::set<unsigned> targets;
for(instructionst::const_iterator
i_it=instructions.begin();
i_it!=instructions.end();
i_it++)
{
std::pair<address_mapt::iterator, bool> a_entry=
address_map.insert(std::make_pair(
i_it->address,
converted_instructiont(i_it, code_skipt())));
assert(a_entry.second);
// addresses are strictly increasing, hence we must have inserted
// a new maximal key
assert(a_entry.first==--address_map.end());
if(i_it->statement!="goto" &&
i_it->statement!="return" &&
!(i_it->statement==patternt("?return")) &&
i_it->statement!="athrow")
{
instructionst::const_iterator next=i_it;
if(++next!=instructions.end())
a_entry.first->second.successors.push_back(next->address);
}
if(i_it->statement=="goto" ||
i_it->statement==patternt("if_?cmp??") ||
i_it->statement==patternt("if??") ||
i_it->statement=="ifnonnull" ||
i_it->statement=="ifnull")
{
assert(!i_it->args.empty());
const unsigned target=safe_string2unsigned(
id2string(to_constant_expr(i_it->args[0]).get_value()));
targets.insert(target);
a_entry.first->second.successors.push_back(target);
}
else if(i_it->statement=="tableswitch" ||
i_it->statement=="lookupswitch")
{
bool is_label=true;
for(instructiont::argst::const_iterator
a_it=i_it->args.begin();
a_it!=i_it->args.end();
a_it++, is_label=!is_label)
{
if(is_label)
{
const unsigned target=safe_string2unsigned(
id2string(to_constant_expr(*a_it).get_value()));
targets.insert(target);
a_entry.first->second.successors.push_back(target);
}
}
}
}
for(address_mapt::iterator
it=address_map.begin();
it!=address_map.end();
++it)
{
for(unsigned s : it->second.successors)
{
address_mapt::iterator a_it=address_map.find(s);
assert(a_it!=address_map.end());
a_it->second.predecessors.insert(it->first);
}
}
std::set<unsigned> working_set;
if(!instructions.empty())
working_set.insert(instructions.front().address);
while(!working_set.empty())
{
std::set<unsigned>::iterator cur=working_set.begin();
address_mapt::iterator a_it=address_map.find(*cur);
assert(a_it!=address_map.end());
working_set.erase(cur);
if(a_it->second.done) continue;
working_set.insert(a_it->second.successors.begin(),
a_it->second.successors.end());
instructionst::const_iterator i_it=a_it->second.source;
stack.swap(a_it->second.stack);
a_it->second.stack.clear();
codet &c=a_it->second.code;
assert(stack.empty() ||
a_it->second.predecessors.size()<=1 ||
has_prefix(stack.front().get_string(ID_C_base_name),
"$stack"));
irep_idt statement=i_it->statement;
exprt arg0=i_it->args.size()>=1?i_it->args[0]:nil_exprt();
exprt arg1=i_it->args.size()>=2?i_it->args[1]:nil_exprt();
const bytecode_infot &bytecode_info=get_bytecode_info(statement);
// deal with _idx suffixes
if(statement.size()>=2 &&
statement[statement.size()-2]=='_' &&
isdigit(statement[statement.size()-1]))
{
arg0=constant_exprt(
std::string(id2string(statement), statement.size()-1, 1),
integer_typet());
statement=std::string(id2string(statement), 0, statement.size()-2);
}
exprt::operandst op=pop(bytecode_info.pop);
exprt::operandst results;
results.resize(bytecode_info.push, nil_exprt());
if(statement=="aconst_null")
{
assert(results.size()==1);
results[0]=gen_zero(java_reference_type(void_typet()));
}
else if(statement=="athrow")
{
assert(op.size()==1 && results.size()==1);
side_effect_expr_throwt throw_expr;
throw_expr.add_source_location()=i_it->source_location;
throw_expr.copy_to_operands(op[0]);
c=code_expressiont(throw_expr);
results[0]=op[0];
}
else if(statement=="checkcast")
{
// checkcast throws an exception in case a cast of object
// on stack to given type fails.
// The stack isn't modified.
assert(op.size()==1 && results.size()==1);
results[0]=op[0];
}
else if(statement=="invokedynamic")
{
// not used in Java
code_typet &code_type=to_code_type(arg0.type());
const code_typet::parameterst ¶meters(code_type.parameters());
pop(parameters.size());
const typet &return_type=code_type.return_type();
if(return_type.id()!=ID_empty)
{
results.resize(1);
results[0]=nil_exprt();
}
}
else if(statement=="invokeinterface" ||
statement=="invokespecial" ||
statement=="invokevirtual" ||
statement=="invokestatic")
{
const bool use_this(statement != "invokestatic");
const bool is_virtual(
statement == "invokevirtual" || statement == "invokeinterface");
code_typet &code_type=to_code_type(arg0.type());
code_typet::parameterst ¶meters(code_type.parameters());
if(use_this)
{
if(parameters.empty() || !parameters[0].get_this())
{
const empty_typet empty;
pointer_typet object_ref_type(empty);
code_typet::parametert this_p(object_ref_type);
this_p.set_this();
this_p.set_base_name("this");
parameters.insert(parameters.begin(), this_p);
}
}
code_function_callt call;
call.add_source_location()=i_it->source_location;
call.arguments() = pop(parameters.size());
// double-check a bit
if(use_this)
{
const exprt &this_arg=call.arguments().front();
assert(this_arg.type().id()==ID_pointer);
}
// do some type adjustment for the arguments,
// as Java promotes arguments
for(unsigned i=0; i<parameters.size(); i++)
{
const typet &type=parameters[i].type();
if(type==java_boolean_type() ||
type==java_char_type() ||
type==java_byte_type() ||
type==java_short_type())
{
assert(i<call.arguments().size());
call.arguments()[i].make_typecast(type);
}
}
// do some type adjustment for return values
const typet &return_type=code_type.return_type();
if(return_type.id()!=ID_empty)
{
// return types are promoted in Java
call.lhs()=tmp_variable("return", return_type);
exprt promoted=java_bytecode_promotion(call.lhs());
results.resize(1);
results[0]=promoted;
}
assert(arg0.id()==ID_virtual_function);
// does the function symbol exist?
irep_idt id=arg0.get(ID_identifier);
if(symbol_table.symbols.find(id)==symbol_table.symbols.end())
{
// no, create stub
symbolt symbol;
symbol.name=id;
symbol.base_name=arg0.get(ID_C_base_name);
symbol.type=arg0.type();
symbol.value.make_nil();
symbol.mode=ID_java;
symbol_table.add(symbol);
}
if(is_virtual)
{
// dynamic binding
assert(use_this);
assert(!call.arguments().empty());
call.function()=arg0;
}
else
{
// static binding
/*if(id == "java::java.lang.String.charAt:(I)C")
call.function()=symbol_exprt("java::__CPROVER_uninterpreted_char_at", arg0.type());
else*/
call.function()=symbol_exprt(arg0.get(ID_identifier), arg0.type());
}
call.function().add_source_location()=i_it->source_location;
c = call;
}
else if(statement=="return")
{
assert(op.empty() && results.empty());
c=code_returnt();
}
else if(statement==patternt("?return"))
{
// Return types are promoted in java, so this might need
// conversion.
assert(op.size()==1 && results.empty());
exprt r=op[0];
if(r.type()!=method_return_type) r=typecast_exprt(r, method_return_type);
c=code_returnt(r);
}
else if(statement==patternt("?astore"))
{
assert(op.size()==3 && results.empty());
char type_char=statement[0];
exprt pointer=
typecast_exprt(op[0], java_array_type(type_char));
const dereference_exprt deref(pointer, pointer.type().subtype());
const member_exprt data_ptr(
deref, "data", pointer_typet(java_type_from_char(type_char)));
plus_exprt data_plus_offset(data_ptr, op[1], data_ptr.type());
typet element_type=data_ptr.type().subtype();
const dereference_exprt element(data_plus_offset, element_type);
c=code_assignt(element, op[2]);
}
else if(statement==patternt("?store"))
{
// store value into some local variable
assert(op.size()==1 && results.empty());
exprt var=variable(arg0, statement[0]);
const bool is_array('a' == statement[0]);
if(is_array)
var.type()=op[0].type();
c=code_assignt(var, op[0]);
}
else if(statement==patternt("?aload"))
{
assert(op.size() == 2 && results.size() == 1);
char type_char=statement[0];
exprt pointer=
typecast_exprt(op[0], java_array_type(type_char));
const dereference_exprt deref(pointer, pointer.type().subtype());
const member_exprt data_ptr(
deref, "data", pointer_typet(java_type_from_char(type_char)));
plus_exprt data_plus_offset(data_ptr, op[1], data_ptr.type());
typet element_type=data_ptr.type().subtype();
dereference_exprt element(data_plus_offset, element_type);
results[0]=java_bytecode_promotion(element);
}
else if(statement==patternt("?load"))
{
// load a value from a local variable
results[0]=variable(arg0, statement[0]);
}
else if(statement=="ldc" || statement=="ldc_w" ||
statement=="ldc2" || statement=="ldc2_w")
{
assert(op.empty() && results.size()==1);
// 1) Pushing a String causes a reference to a java.lang.String object
// to be constructed and pushed onto the operand stack.
// 2) Pushing an int or a float causes a primitive value to be pushed
// onto the stack.
// 3) Pushing a Class constant causes a reference to a java.lang.Class
// to be pushed onto the operand stack
if(arg0.id()==ID_java_string_literal)
{
// these need to be references to java.lang.String
results[0]=arg0;
symbol_typet string_type("java::java.lang.String");
results[0].type()=pointer_typet(string_type);
}
else if(arg0.id()==ID_type)
{
irep_idt class_id=arg0.type().get(ID_identifier);
symbol_typet java_lang_Class("java::java.lang.Class");
symbol_exprt symbol_expr(id2string(class_id)+"@class_model", java_lang_Class);
address_of_exprt address_of_expr(symbol_expr);
results[0]=address_of_expr;
}
else if(arg0.id()==ID_constant)
{
results[0]=arg0;
}
else
{
error() << "unexpected ldc argument" << eom;
throw 0;
}
}
else if(statement=="goto" || statement=="goto_w")
{
assert(op.empty() && results.empty());
irep_idt number=to_constant_expr(arg0).get_value();
code_gotot code_goto(label(number));
c=code_goto;
}
else if(statement=="iconst_m1")
{
assert(results.size()==1);
results[0]=from_integer(-1, java_int_type());
}
else if(statement==patternt("?const"))
{
assert(results.size() == 1);
const char type_char=statement[0];
const bool is_double('d' == type_char);
const bool is_float('f' == type_char);
if(is_double || is_float)
{
const ieee_float_spect spec(
is_float ?
ieee_float_spect::single_precision() :
ieee_float_spect::double_precision());
ieee_floatt value(spec);
const typet &arg_type(arg0.type());
if(ID_integer == arg_type.id())
value.from_integer(arg0.get_int(ID_value));
else
value.from_expr(to_constant_expr(arg0));
results[0] = value.to_expr();
}
else
{
const unsigned int value(arg0.get_unsigned_int(ID_value));
const typet type=java_type_from_char(statement[0]);
results[0] = as_number(value, type);
}
}
else if(statement==patternt("?ipush"))
{
assert(results.size()==1);
results[0]=typecast_exprt(arg0, java_int_type());
}
else if(statement==patternt("if_?cmp??"))
{
irep_idt number=to_constant_expr(arg0).get_value();
assert(op.size()==2 && results.empty());
code_ifthenelset code_branch;
const irep_idt cmp_op=get_if_cmp_operator(statement);
binary_relation_exprt condition(op[0], cmp_op, op[1]);
cast_if_necessary(condition);
code_branch.cond()=condition;
code_branch.then_case()=code_gotot(label(number));
code_branch.then_case().add_source_location()=i_it->source_location;
code_branch.add_source_location()=i_it->source_location;
c=code_branch;
}
else if(statement==patternt("if??"))
{
const irep_idt id=
statement=="ifeq"?ID_equal:
statement=="ifne"?ID_notequal:
statement=="iflt"?ID_lt:
statement=="ifge"?ID_ge:
statement=="ifgt"?ID_gt:
statement=="ifle"?ID_le:
(assert(false), "");
irep_idt number=to_constant_expr(arg0).get_value();
assert(op.size()==1 && results.empty());
code_ifthenelset code_branch;
code_branch.cond()=binary_relation_exprt(op[0], id, gen_zero(op[0].type()));
code_branch.cond().add_source_location()=i_it->source_location;
code_branch.then_case()=code_gotot(label(number));
code_branch.then_case().add_source_location()=i_it->source_location;
code_branch.add_source_location()=i_it->source_location;
c=code_branch;
}
else if(statement==patternt("ifnonnull"))
{
irep_idt number=to_constant_expr(arg0).get_value();
assert(op.size()==1 && results.empty());
code_ifthenelset code_branch;
const typecast_exprt lhs(op[0], pointer_typet());
const exprt rhs(gen_zero(lhs.type()));
code_branch.cond()=binary_relation_exprt(lhs, ID_notequal, rhs);
code_branch.then_case()=code_gotot(label(number));
code_branch.then_case().add_source_location()=i_it->source_location;
code_branch.add_source_location()=i_it->source_location;
c=code_branch;
}
else if(statement==patternt("ifnull"))
{
assert(op.size()==1 && results.empty());
irep_idt number=to_constant_expr(arg0).get_value();
code_ifthenelset code_branch;
const typecast_exprt lhs(op[0], pointer_typet(empty_typet()));
const exprt rhs(gen_zero(lhs.type()));
code_branch.cond()=binary_relation_exprt(lhs, ID_equal, rhs);
code_branch.then_case()=code_gotot(label(number));
code_branch.then_case().add_source_location()=i_it->source_location;
code_branch.add_source_location()=i_it->source_location;
c=code_branch;
}
else if(statement=="iinc")
{
code_assignt code_assign;
code_assign.lhs()=variable(arg0, 'i');
code_assign.rhs()=plus_exprt(
variable(arg0, 'i'),
typecast_exprt(arg1, java_int_type()));
c=code_assign;
}
else if(statement==patternt("?xor"))
{
assert(op.size()==2 && results.size()==1);
results[0]=bitxor_exprt(op[0], op[1]);
}
else if(statement==patternt("?or"))
{
assert(op.size()==2 && results.size()==1);
results[0]=bitor_exprt(op[0], op[1]);
}
else if(statement==patternt("?and"))
{
assert(op.size()==2 && results.size()==1);
results[0]=bitand_exprt(op[0], op[1]);
}
else if(statement==patternt("?shl"))
{
assert(op.size()==2 && results.size()==1);
results[0]=shl_exprt(op[0], op[1]);
}
else if(statement==patternt("?shr"))
{
assert(op.size()==2 && results.size()==1);
results[0]=ashr_exprt(op[0], op[1]);
}
else if(statement==patternt("?ushr"))
{
assert(op.size()==2 && results.size()==1);
const typet type(java_type_from_char(statement[0]));
const unsigned int width(type.get_unsigned_int(ID_width));
typet target=unsigned_long_int_type();
target.set(ID_width, width);
const typecast_exprt lhs(op[0], target);
const typecast_exprt rhs(op[1], target);
results[0]=lshr_exprt(lhs, rhs);
}
else if(statement==patternt("?add"))
{
assert(op.size()==2 && results.size()==1);
results[0]=plus_exprt(op[0], op[1]);
}
else if(statement==patternt("?sub"))
{
assert(op.size()==2 && results.size()==1);
results[0]=minus_exprt(op[0], op[1]);
}
else if(statement==patternt("?div"))
{
assert(op.size()==2 && results.size()==1);
results[0]=div_exprt(op[0], op[1]);
}
else if(statement==patternt("?mul"))
{
assert(op.size()==2 && results.size()==1);
results[0]=mult_exprt(op[0], op[1]);
}
else if(statement==patternt("?neg"))
{
assert(op.size()==1 && results.size()==1);
results[0]=unary_minus_exprt(op[0], op[0].type());
}
else if(statement==patternt("?rem"))
{
assert(op.size()==2 && results.size()==1);
if(statement=="frem" || statement=="drem")
results[0]=rem_exprt(op[0], op[1]);
else
results[0]=mod_exprt(op[0], op[1]);
}
else if(statement==patternt("?cmp"))
{
assert(op.size() == 2 && results.size() == 1);
// The integer result on the stack is:
// 0 if op[0] equals op[1]
// -1 if op[0] is less than op[1]
// 1 if op[0] is greater than op[1]
const typet t=java_int_type();
results[0]=
if_exprt(binary_relation_exprt(op[0], ID_equal, op[1]), gen_zero(t),
if_exprt(binary_relation_exprt(op[0], ID_gt, op[1]), from_integer(1, t),
from_integer(-1, t)));
}
else if(statement==patternt("?cmp?"))
{
assert(op.size()==2 && results.size()==1);
const floatbv_typet type(to_floatbv_type(java_type_from_char(statement[0])));
const ieee_float_spect spec(type);
const ieee_floatt nan(ieee_floatt::NaN(spec));
const constant_exprt nan_expr(nan.to_expr());
const int nan_value(statement[4] == 'l' ? -1 : 1);
const typet result_type(java_int_type());
const exprt nan_result(from_integer(nan_value, result_type));
// (value1 == NaN || value2 == NaN) ? nan_value : value1 < value2 ? -1 : value2 < value1 1 ? 1 : 0;
// (value1 == NaN || value2 == NaN) ? nan_value : value1 == value2 ? 0 : value1 < value2 -1 ? 1 : 0;
results[0]=
if_exprt(or_exprt(ieee_float_equal_exprt(nan_expr, op[0]), ieee_float_equal_exprt(nan_expr, op[1])), nan_result,
if_exprt(ieee_float_equal_exprt(op[0], op[1]), gen_zero(result_type),
if_exprt(binary_relation_exprt(op[0], ID_lt, op[1]), from_integer(-1, result_type), from_integer(1, result_type))));
}
else if(statement==patternt("?cmpl"))
{
assert(op.size()==2 && results.size()==1);
results[0]=binary_relation_exprt(op[0], ID_lt, op[1]);
}
else if(statement=="dup")
{
assert(op.size()==1 && results.size()==2);
results[0]=results[1]=op[0];
}
else if(statement=="dup_x1")
{
assert(op.size()==2 && results.size()==3);
results[0]=op[1];
results[1]=op[0];
results[2]=op[1];
}
else if(statement=="dup_x2")
{
assert(op.size()==3 && results.size()==4);
results[0]=op[2];
results[1]=op[0];
results[2]=op[1];
results[3]=op[2];
}
// dup2* behaviour depends on the size of the operands on the
// stack
else if(statement=="dup2")
{
assert(!stack.empty() && results.empty());
if(stack.back().type().get_unsigned_int(ID_width)==32)
op=pop(2);
else
op=pop(1);
results.insert(results.end(), op.begin(), op.end());
results.insert(results.end(), op.begin(), op.end());
}
else if(statement=="dup2_x1")
{
assert(!stack.empty() && results.empty());
if(stack.back().type().get_unsigned_int(ID_width)==32)
op=pop(3);
else
op=pop(2);
results.insert(results.end(), op.begin()+1, op.end());
results.insert(results.end(), op.begin(), op.end());
}
else if(statement=="dup2_x2")
{
assert(!stack.empty() && results.empty());
if(stack.back().type().get_unsigned_int(ID_width)==32)
op=pop(2);
else
op=pop(1);
assert(!stack.empty());
exprt::operandst op2;
if(stack.back().type().get_unsigned_int(ID_width)==32)
op2=pop(2);
else
op2=pop(1);
results.insert(results.end(), op.begin(), op.end());
results.insert(results.end(), op2.begin(), op2.end());
results.insert(results.end(), op.begin(), op.end());
}
else if(statement=="dconst")
{
assert(op.empty() && results.size()==1);
}
else if(statement=="fconst")
{
assert(op.empty() && results.size()==1);
}
else if(statement=="getfield")
{
assert(op.size()==1 && results.size()==1);
results[0]=to_member(op[0], arg0);
}
else if(statement=="getstatic")
{
assert(op.empty() && results.size()==1);
symbol_exprt symbol_expr(arg0.type());
symbol_expr.set_identifier(arg0.get_string(ID_class)+"."+arg0.get_string(ID_component_name));
results[0]=symbol_expr;
}
else if(statement=="putfield")
{
assert(op.size()==2 && results.size()==0);
c = code_assignt(to_member(op[0], arg0), op[1]);
}
else if(statement=="putstatic")
{
assert(op.size()==1 && results.empty());
symbol_exprt symbol_expr(arg0.type());
symbol_expr.set_identifier(arg0.get_string(ID_class)+"."+arg0.get_string(ID_component_name));
c=code_assignt(symbol_expr, op[0]);
}
else if(statement==patternt("?2?")) // i2c etc.
{
assert(op.size()==1 && results.size()==1);
results[0]=typecast_exprt(op[0], java_type_from_char(statement[2]));
}
else if(statement=="new")
{
// use temporary since the stack symbol might get duplicated
assert(op.empty() && results.size()==1);
const pointer_typet ref_type(arg0.type());
exprt java_new_expr=side_effect_exprt(ID_java_new, ref_type);
if(!i_it->source_location.get_line().empty())
java_new_expr.add_source_location()=i_it->source_location;
const exprt tmp=tmp_variable("new", ref_type);
c=code_assignt(tmp, java_new_expr);
results[0]=tmp;
}
else if(statement=="newarray" ||
statement=="anewarray")
{
// the op is the array size
assert(op.size()==1 && results.size()==1);
char element_type;
if(statement=="newarray")
{
irep_idt id=arg0.type().id();
if(id==ID_bool)
element_type='z';
else if(id==ID_char)
element_type='c';
else if(id==ID_float)
element_type='f';
else if(id==ID_double)
element_type='d';
else if(id==ID_byte)
element_type='b';
else if(id==ID_short)
element_type='s';
else if(id==ID_int)
element_type='i';
else if(id==ID_long)
element_type='j';
else
element_type='?';
}
else
element_type='a';
const pointer_typet ref_type=java_array_type(element_type);
side_effect_exprt java_new_array(ID_java_new_array, ref_type);
java_new_array.copy_to_operands(op[0]);
if(!i_it->source_location.get_line().empty())
java_new_array.add_source_location()=i_it->source_location;
const exprt tmp=tmp_variable("newarray", ref_type);
c=code_assignt(tmp, java_new_array);
results[0]=tmp;
}
else if(statement=="multianewarray")
{
// The first argument is the type, the second argument is the dimension.
// The size of each dimension is on the stack.
irep_idt number=to_constant_expr(arg1).get_value();
unsigned dimension=safe_c_str2unsigned(number.c_str());
op=pop(dimension);
assert(results.size()==1);
// arg0.type()
const pointer_typet ref_type=java_array_type('a');
side_effect_exprt java_new_array(ID_java_new_array, ref_type);
java_new_array.operands()=op;
if(!i_it->source_location.get_line().empty())
java_new_array.add_source_location()=i_it->source_location;
const exprt tmp=tmp_variable("newarray", ref_type);
c=code_assignt(tmp, java_new_array);
results[0]=tmp;
}
else if(statement=="arraylength")
{
assert(op.size()==1 && results.size()==1);
exprt pointer=
typecast_exprt(op[0], java_array_type(statement[0]));
const dereference_exprt array(pointer, pointer.type().subtype());
assert(pointer.type().subtype().id()==ID_symbol);
const member_exprt length(array, "length", java_int_type());
results[0]=length;
}
else if(statement=="tableswitch" ||
statement=="lookupswitch")
{
assert(op.size()==1 && results.size()==0);
// we turn into switch-case
code_switcht code_switch;
code_switch.add_source_location()=i_it->source_location;
code_switch.value()=op[0];
code_blockt code_block;
code_block.add_source_location()=i_it->source_location;
bool is_label=true;
for(instructiont::argst::const_iterator
a_it=i_it->args.begin();
a_it!=i_it->args.end();
a_it++, is_label=!is_label)
{
if(is_label)
{
code_switch_caset code_case;
code_case.add_source_location()=i_it->source_location;
irep_idt number=to_constant_expr(*a_it).get_value();
code_case.code()=code_gotot(label(number));
code_case.code().add_source_location()=i_it->source_location;
if(a_it==i_it->args.begin())
code_case.set_default();
else
{
instructiont::argst::const_iterator prev=a_it;
prev--;
code_case.case_op()=typecast_exprt(*prev, op[0].type());
code_case.case_op().add_source_location()=i_it->source_location;
}
code_block.add(code_case);
}
}
code_switch.body()=code_block;
c=code_switch;
}
else if(statement=="pop" || statement=="pop2")
{
// these are skips
c=code_skipt();
// pop2 removes two single-word items from the stack (e.g. two
// integers, or an integer and an object reference) or one
// two-word item (i.e. a double or a long).
// http://cs.au.dk/~mis/dOvs/jvmspec/ref-pop2.html
if(statement=="pop2" &&
op[0].type().get_unsigned_int(ID_width)==32)
pop(1);
}
else if(statement=="instanceof")
{
assert(op.size()==1 && results.size()==1);
results[0]=
binary_predicate_exprt(op[0], "java_instanceof", arg0);
}
else
{
c=codet(statement);
c.operands()=op;
}
if(!i_it->source_location.get_line().empty())
c.add_source_location()=i_it->source_location;
push(results);
a_it->second.done=true;
for(std::list<unsigned>::iterator
it=a_it->second.successors.begin();
it!=a_it->second.successors.end();
++it)
{
address_mapt::iterator a_it2=address_map.find(*it);
assert(a_it2!=address_map.end());
if(!stack.empty() && a_it2->second.predecessors.size()>1)
{
// copy into temporaries
code_blockt more_code;
// introduce temporaries when successor is seen for the first
// time
if(a_it2->second.stack.empty())
{
for(stackt::iterator s_it=stack.begin();
s_it!=stack.end();
++s_it)
{
symbol_exprt lhs=tmp_variable("$stack", s_it->type());
code_assignt a(lhs, *s_it);
more_code.copy_to_operands(a);
s_it->swap(lhs);
}
}
else
{
assert(a_it2->second.stack.size()==stack.size());
stackt::const_iterator os_it=a_it2->second.stack.begin();
for(stackt::iterator s_it=stack.begin();
s_it!=stack.end();
++s_it)
{
assert(has_prefix(os_it->get_string(ID_C_base_name),
"$stack"));
symbol_exprt lhs=to_symbol_expr(*os_it);
code_assignt a(lhs, *s_it);
more_code.copy_to_operands(a);
s_it->swap(lhs);
++os_it;
}
}
if(results.empty())
{
more_code.copy_to_operands(c);
c.swap(more_code);
}
else
{
c.make_block();
forall_operands(o_it, more_code)
c.copy_to_operands(*o_it);
}
}
a_it2->second.stack=stack;
}
}
// TODO: add exception handlers from exception table
// review successor computation of athrow!
code_blockt code;
// temporaries
for(const auto & var : tmp_vars)
{
code.add(code_declt(var));
}
for(const auto & it : address_map)
{
const unsigned address=it.first;
assert(it.first==it.second.source->address);
const codet &c=it.second.code;
if(targets.find(address)!=targets.end())
code.add(code_labelt(label(i2string(address)), c));
else if(c.get_statement()!=ID_skip)
code.add(c);
}
return code;
}
void goto_checkt::pointer_validity_check(
const dereference_exprt &expr,
const guardt &guard)
{
if(!enable_pointer_check)
return;
const exprt &pointer=expr.op0();
const typet &pointer_type=to_pointer_type(ns.follow(pointer.type()));
assert(base_type_eq(pointer_type.subtype(), expr.type(), ns));
local_bitvector_analysist::flagst flags=
local_bitvector_analysis->get(t, pointer);
const typet &dereference_type=pointer_type.subtype();
// For Java, we only need to check for null
if(mode==ID_java)
{
if(flags.is_unknown() || flags.is_null())
{
notequal_exprt not_eq_null(pointer, gen_zero(pointer.type()));
add_guarded_claim(
not_eq_null,
"reference is null",
"pointer dereference",
expr.find_source_location(),
expr,
guard);
}
}
else
{
if(flags.is_unknown() || flags.is_null())
{
add_guarded_claim(
not_exprt(null_pointer(pointer)),
"dereference failure: pointer NULL",
"pointer dereference",
expr.find_source_location(),
expr,
guard);
}
if(flags.is_unknown())
add_guarded_claim(
not_exprt(invalid_pointer(pointer)),
"dereference failure: pointer invalid",
"pointer dereference",
expr.find_source_location(),
expr,
guard);
if(flags.is_uninitialized())
add_guarded_claim(
not_exprt(invalid_pointer(pointer)),
"dereference failure: pointer uninitialized",
"pointer dereference",
expr.find_source_location(),
expr,
guard);
if(mode != ID_java)
{
if(flags.is_unknown() || flags.is_dynamic_heap())
add_guarded_claim(
not_exprt(deallocated(pointer, ns)),
"dereference failure: deallocated dynamic object",
"pointer dereference",
expr.find_source_location(),
expr,
guard);
if(flags.is_unknown() || flags.is_dynamic_local())
add_guarded_claim(
not_exprt(dead_object(pointer, ns)),
"dereference failure: dead object",
"pointer dereference",
expr.find_source_location(),
expr,
guard);
}
if(enable_bounds_check)
{
if(flags.is_unknown() || flags.is_dynamic_heap())
{
exprt dynamic_bounds=
or_exprt(dynamic_object_lower_bound(pointer),
dynamic_object_upper_bound(pointer, dereference_type, ns));
add_guarded_claim(
implies_exprt(malloc_object(pointer, ns), not_exprt(dynamic_bounds)),
"dereference failure: dynamic object bounds",
"pointer dereference",
expr.find_source_location(),
expr,
guard);
}
}
if(enable_bounds_check)
{
if(flags.is_unknown() ||
flags.is_dynamic_local() ||
flags.is_static_lifetime())
{
exprt object_bounds=
or_exprt(object_lower_bound(pointer),
object_upper_bound(pointer, dereference_type, ns));
add_guarded_claim(
or_exprt(dynamic_object(pointer), not_exprt(object_bounds)),
"dereference failure: object bounds",
"pointer dereference",
expr.find_source_location(),
expr,
guard);
}
}
}
}
void goto_checkt::nan_check(
const exprt &expr,
const guardt &guard)
{
if(!enable_nan_check)
return;
// first, check type
if(expr.type().id()!=ID_floatbv)
return;
if(expr.id()!=ID_plus &&
expr.id()!=ID_mult &&
expr.id()!=ID_div &&
expr.id()!=ID_minus)
return;
// add NaN subgoal
exprt isnan;
if(expr.id()==ID_div)
{
assert(expr.operands().size()==2);
// there a two ways to get a new NaN on division:
// 0/0 = NaN and x/inf = NaN
// (note that x/0 = +-inf for x!=0 and x!=inf)
exprt zero_div_zero=and_exprt(
ieee_float_equal_exprt(expr.op0(), gen_zero(expr.op0().type())),
ieee_float_equal_exprt(expr.op1(), gen_zero(expr.op1().type())));
exprt div_inf=unary_exprt(ID_isinf, expr.op1(), bool_typet());
isnan=or_exprt(zero_div_zero, div_inf);
}
else if(expr.id()==ID_mult)
{
if(expr.operands().size()>=3)
return nan_check(make_binary(expr), guard);
assert(expr.operands().size()==2);
// Inf * 0 is NaN
exprt inf_times_zero=and_exprt(
unary_exprt(ID_isinf, expr.op0(), bool_typet()),
ieee_float_equal_exprt(expr.op1(), gen_zero(expr.op1().type())));
exprt zero_times_inf=and_exprt(
ieee_float_equal_exprt(expr.op1(), gen_zero(expr.op1().type())),
unary_exprt(ID_isinf, expr.op0(), bool_typet()));
isnan=or_exprt(inf_times_zero, zero_times_inf);
}
else if(expr.id()==ID_plus)
{
if(expr.operands().size()>=3)
return nan_check(make_binary(expr), guard);
assert(expr.operands().size()==2);
// -inf + +inf = NaN and +inf + -inf = NaN,
// i.e., signs differ
ieee_float_spect spec=ieee_float_spect(to_floatbv_type(expr.type()));
exprt plus_inf=ieee_floatt::plus_infinity(spec).to_expr();
exprt minus_inf=ieee_floatt::minus_infinity(spec).to_expr();
isnan=or_exprt(
and_exprt(equal_exprt(expr.op0(), minus_inf), equal_exprt(expr.op1(), plus_inf)),
and_exprt(equal_exprt(expr.op0(), plus_inf), equal_exprt(expr.op1(), minus_inf)));
}
else if(expr.id()==ID_minus)
{
assert(expr.operands().size()==2);
// +inf - +inf = NaN and -inf - -inf = NaN,
// i.e., signs match
ieee_float_spect spec=ieee_float_spect(to_floatbv_type(expr.type()));
exprt plus_inf=ieee_floatt::plus_infinity(spec).to_expr();
exprt minus_inf=ieee_floatt::minus_infinity(spec).to_expr();
isnan=or_exprt(
and_exprt(equal_exprt(expr.op0(), plus_inf), equal_exprt(expr.op1(), plus_inf)),
and_exprt(equal_exprt(expr.op0(), minus_inf), equal_exprt(expr.op1(), minus_inf)));
}
else
assert(false);
isnan.make_not();
add_guarded_claim(
isnan,
"NaN on "+expr.id_string(),
"NaN",
expr.find_source_location(),
expr,
guard);
}
bool strategy_solver_binsearcht::iterate(invariantt &_inv)
{
tpolyhedra_domaint::templ_valuet &inv=
static_cast<tpolyhedra_domaint::templ_valuet &>(_inv);
bool improved=false;
solver.new_context(); // for improvement check
exprt inv_expr=tpolyhedra_domain.to_pre_constraints(inv);
#if 0
debug() << "improvement check: " << eom;
debug() << "pre-inv: " << from_expr(ns, "", inv_expr) << eom;
#endif
solver << inv_expr;
exprt::operandst strategy_cond_exprs;
tpolyhedra_domain.make_not_post_constraints(
inv, strategy_cond_exprs, strategy_value_exprs);
strategy_cond_literals.resize(strategy_cond_exprs.size());
#if 0
debug() << "post-inv: ";
#endif
for(std::size_t i=0; i<strategy_cond_exprs.size(); i++)
{
#if 0
debug() << (i>0 ? " || " : "") << from_expr(ns, "", strategy_cond_exprs[i]);
#endif
strategy_cond_literals[i]=solver.convert(strategy_cond_exprs[i]);
// solver.set_frozen(strategy_cond_literals[i]);
strategy_cond_exprs[i]=literal_exprt(strategy_cond_literals[i]);
}
#if 0
debug() << eom;
#endif
solver << or_exprt(disjunction(strategy_cond_exprs),
literal_exprt(assertion_check));
#if 0
debug() << "solve(): ";
#endif
if(solver()==decision_proceduret::D_SATISFIABLE) // improvement check
{
#if 0
debug() << "SAT" << eom;
#endif
#if 0
for(std::size_t i=0; i<solver.formula.size(); i++)
{
debug() << "literal: " << solver.formula[i]
<< " " << solver.l_get(solver.formula[i]) << eom;
}
for(std::size_t i=0; i<tpolyhedra_domain.template_size(); i++)
{
exprt c=tpolyhedra_domain.get_row_post_constraint(i, inv[i]);
debug() << "cond: " << from_expr(ns, "", c) << " "
<< from_expr(ns, "", solver.get(c)) << eom;
debug() << "expr: " << from_expr(ns, "", strategy_value_exprs[i]) << " "
<< from_expr(
ns, "", simplify_const(solver.get(strategy_value_exprs[i])))
<< eom;
debug() << "guards: "
<< from_expr(ns, "", tpolyhedra_domain.templ[i].pre_guard) << " "
<< from_expr(
ns, "", solver.get(tpolyhedra_domain.templ[i].pre_guard))
<< eom;
debug() << "guards: "
<< from_expr(ns, "", tpolyhedra_domain.templ[i].post_guard)
<< " "
<< from_expr(
ns, "", solver.get(tpolyhedra_domain.templ[i].post_guard))
<< eom;
}
#endif
std::size_t row=0;
for(; row<strategy_cond_literals.size(); row++)
{
if(solver.l_get(strategy_cond_literals[row]).is_true())
break; // we've found a row to improve
}
if(row==strategy_cond_literals.size())
{ // No, we haven't found one.
// This can only happen if the assertions failed.
solver.pop_context();
return FAILED;
}
debug() << "improving row: " << row << eom;
std::set<tpolyhedra_domaint::rowt> improve_rows;
improve_rows.insert(row);
tpolyhedra_domaint::row_valuet upper=
tpolyhedra_domain.get_max_row_value(row);
tpolyhedra_domaint::row_valuet lower=
simplify_const(solver.get(strategy_value_exprs[row]));
solver.pop_context(); // improvement check
solver.new_context(); // symbolic value system
exprt pre_inv_expr=
tpolyhedra_domain.to_symb_pre_constraints(inv, improve_rows);
solver << pre_inv_expr;
exprt post_inv_expr=tpolyhedra_domain.get_row_symb_post_constraint(row);
solver << post_inv_expr;
#if 0
debug() << "symbolic value system: " << eom;
debug() << "pre-inv: " << from_expr(ns, "", pre_inv_expr) << eom;
debug() << "post-inv: " << from_expr(ns, "", post_inv_expr) << eom;
#endif
while(tpolyhedra_domain.less_than(lower, upper))
{
tpolyhedra_domaint::row_valuet middle=
tpolyhedra_domain.between(lower, upper);
if(!tpolyhedra_domain.less_than(lower, middle))
middle=upper;
// row_symb_value >= middle
exprt c=
tpolyhedra_domain.get_row_symb_value_constraint(row, middle, true);
#if 0
debug() << "upper: " << from_expr(ns, "", upper) << eom;
debug() << "middle: " << from_expr(ns, "", middle) << eom;
debug() << "lower: " << from_expr(ns, "", lower) << eom;
#endif
solver.new_context(); // binary search iteration
#if 0
debug() << "constraint: " << from_expr(ns, "", c) << eom;
#endif
solver << c;
if(solver()==decision_proceduret::D_SATISFIABLE)
{
#if 0
debug() << "SAT" << eom;
#endif
#if 0
for(std::size_t i=0; i<tpolyhedra_domain.template_size(); i++)
{
debug() << from_expr(ns, "", tpolyhedra_domain.get_row_symb_value(i))
<< " " << from_expr(
ns, "", solver.get(tpolyhedra_domain.get_row_symb_value(i)))
<< eom;
}
#endif
#if 0
for(const auto &rm : renaming_map)
{
debug() << "replace_map (1st): "
<< from_expr(ns, "", rm.first) << " "
<< from_expr(ns, "", solver.get(rm.first)) << eom;
debug() << "replace_map (2nd): "
<< from_expr(ns, "", rm.second) << " "
<< from_expr(ns, "", solver.get(rm.second)) << eom;
}
#endif
lower=simplify_const(
solver.get(tpolyhedra_domain.get_row_symb_value(row)));
}
else
{
#if 0
debug() << "UNSAT" << eom;
#endif
#if 0
for(std::size_t i=0; i<solver.formula.size(); ++i)
{
if(solver.solver->is_in_conflict(solver.formula[i]))
debug() << "is_in_conflict: " << solver.formula[i] << eom;
else
debug() << "not_in_conflict: " << solver.formula[i] << eom;
}
#endif
if(!tpolyhedra_domain.less_than(middle, upper))
middle=lower;
upper=middle;
}
solver.pop_context(); // binary search iteration
}
debug() << "update value: " << from_expr(ns, "", lower) << eom;
solver.pop_context(); // symbolic value system
tpolyhedra_domain.set_row_value(row, lower, inv);
improved=true;
}
else
{
#if 0
debug() << "UNSAT" << eom;
#endif
#ifdef DEBUG_FORMULA
for(std::size_t i=0; i<solver.formula.size(); ++i)
{
if(solver.solver->is_in_conflict(solver.formula[i]))
debug() << "is_in_conflict: " << solver.formula[i] << eom;
else
debug() << "not_in_conflict: " << solver.formula[i] << eom;
}
#endif
solver.pop_context(); // improvement check
}
return improved;
}
guardt &operator |= (guardt &g1, const guardt &g2)
{
if(g2.is_false() || g1.is_true()) return g1;
if(g1.is_false() || g2.is_true()) { g1=g2; return g1; }
if(g1.id()!=ID_and || g2.id()!=ID_and)
{
exprt tmp(g2);
tmp.make_not();
if(tmp==g1)
g1.make_true();
else
g1=or_exprt(g1, g2);
// TODO: make simplify more capable and apply here
return g1;
}
// find common prefix
sort_and_join(g1);
guardt g2_sorted=g2;
sort_and_join(g2_sorted);
exprt::operandst &op1=g1.operands();
const exprt::operandst &op2=g2_sorted.operands();
exprt::operandst n_op1, n_op2;
n_op1.reserve(op1.size());
n_op2.reserve(op2.size());
exprt::operandst::iterator it1=op1.begin();
for(exprt::operandst::const_iterator
it2=op2.begin();
it2!=op2.end();
++it2)
{
while(it1!=op1.end() && *it1<*it2)
{
n_op1.push_back(*it1);
it1=op1.erase(it1);
}
if(it1!=op1.end() && *it1==*it2)
++it1;
else
n_op2.push_back(*it2);
}
while(it1!=op1.end())
{
n_op1.push_back(*it1);
it1=op1.erase(it1);
}
if(n_op2.empty()) return g1;
// end of common prefix
exprt and_expr1=conjunction(n_op1);
exprt and_expr2=conjunction(n_op2);
g1=conjunction(op1);
exprt tmp(and_expr2);
tmp.make_not();
if(tmp!=and_expr1)
{
if(and_expr1.is_true() || and_expr2.is_true())
{
}
else
// TODO: make simplify more capable and apply here
g1.add(or_exprt(and_expr1, and_expr2));
}
return g1;
}
bool solver_enumerationt::iterate(invariantt &_inv)
{
tpolyhedra_domaint::templ_valuet &inv =
static_cast<tpolyhedra_domaint::templ_valuet &>(_inv);
bool improved = false;
literalt activation_literal = new_context();
exprt inv_expr = tpolyhedra_domain.to_pre_constraints(inv);
debug() << "pre-inv: " << from_expr(ns,"",inv_expr) << eom;
#ifndef DEBUG_FORMULA
solver << or_exprt(inv_expr, literal_exprt(activation_literal));
#else
debug() << "literal " << activation_literal << eom;
literalt l = solver.convert(or_exprt(inv_expr, literal_exprt(activation_literal)));
if(!l.is_constant())
{
debug() << "literal " << l << ": " << from_expr(ns,"",or_exprt(inv_expr, literal_exprt(activation_literal))) <<eom;
formula.push_back(l);
}
#endif
exprt::operandst strategy_cond_exprs;
tpolyhedra_domain.make_not_post_constraints(inv,
strategy_cond_exprs, strategy_value_exprs);
#ifndef DEBUG_FORMULA
solver << or_exprt(disjunction(strategy_cond_exprs),
literal_exprt(activation_literal));
#else
exprt expr_act=
or_exprt(disjunction(strategy_cond_exprs),
literal_exprt(activation_literal));
l = solver.convert(expr_act);
if(!l.is_constant())
{
debug() << "literal " << l << ": " <<
from_expr(ns,"", expr_act) <<eom;
formula.push_back(l);
}
#endif
debug() << "solve(): ";
#ifdef DEBUG_FORMULA
bvt whole_formula = formula;
whole_formula.insert(whole_formula.end(),activation_literals.begin(),activation_literals.end());
solver.set_assumptions(whole_formula);
#endif
if(solve() == decision_proceduret::D_SATISFIABLE)
{
debug() << "SAT" << eom;
#if 0
for(unsigned i=0; i<whole_formula.size(); i++)
{
debug() << "literal: " << whole_formula[i] << " " <<
solver.l_get(whole_formula[i]) << eom;
}
for(unsigned i=0; i<tpolyhedra_domain.template_size(); i++)
{
exprt c = tpolyhedra_domain.get_row_constraint(i,inv[i]);
debug() << "cond: " << from_expr(ns, "", c) << " " <<
from_expr(ns, "", solver.get(c)) << eom;
debug() << "guards: " << from_expr(ns, "", tpolyhedra_domain.templ.pre_guards[i]) <<
" " << from_expr(ns, "", solver.get(tpolyhedra_domain.templ.pre_guards[i])) << eom;
debug() << "guards: " << from_expr(ns, "", tpolyhedra_domain.templ.post_guards[i]) << " "
<< from_expr(ns, "", solver.get(tpolyhedra_domain.templ.post_guards[i])) << eom; }
for(replace_mapt::const_iterator
it=renaming_map.begin();
it!=renaming_map.end();
++it)
{
debug() << "replace_map (1st): " << from_expr(ns, "", it->first) << " " <<
from_expr(ns, "", solver.get(it->first)) << eom;
debug() << "replace_map (2nd): " << from_expr(ns, "", it->second) << " " <<
from_expr(ns, "", solver.get(it->second)) << eom;
}
#endif
tpolyhedra_domaint::templ_valuet new_value;
tpolyhedra_domain.initialize(new_value);
for(unsigned row=0;row<tpolyhedra_domain.template_size(); row++)
{
tpolyhedra_domaint::row_valuet v =
simplify_const(solver.get(strategy_value_exprs[row]));
tpolyhedra_domain.set_row_value(row,v,new_value);
debug() << "value: " << from_expr(ns,"",v) << eom;
}
tpolyhedra_domain.join(inv,new_value);
improved = true;
}
else
{
debug() << "UNSAT" << eom;
#ifdef DEBUG_FORMULA
for(unsigned i=0; i<whole_formula.size(); i++)
{
if(solver.is_in_conflict(whole_formula[i]))
debug() << "is_in_conflict: " << whole_formula[i] << eom;
else
debug() << "not_in_conflict: " << whole_formula[i] << eom;
}
#endif
}
pop_context();
return improved;
}
exprt summarizer_bw_termt::compute_precondition(
local_SSAt &SSA,
summaryt &summary,
const exprt::operandst &postconditions,
incremental_solvert &solver,
template_generator_summaryt &template_generator,
bool context_sensitive)
{
exprt postcond=not_exprt(conjunction(postconditions));
// compute backward summary
exprt bw_transformer, bw_invariant, bw_precondition;
if(!template_generator.out_vars().empty())
{
ssa_analyzert analyzer;
analyzer.set_message_handler(get_message_handler());
analyzer(solver, SSA, postcond, template_generator);
analyzer.get_result(bw_transformer, template_generator.inout_vars());
analyzer.get_result(bw_invariant, template_generator.loop_vars());
analyzer.get_result(bw_precondition, template_generator.out_vars());
// statistics
solver_instances+=analyzer.get_number_of_solver_instances();
solver_calls+=analyzer.get_number_of_solver_calls();
}
#if 1
// TODO: yet another workaround for ssa_analyzer
// not being able to handle empty templates properly
else
{
solver << SSA;
solver.new_context();
solver << SSA.get_enabling_exprs();
solver << postcond;
exprt result=true_exprt();
if(solver()==decision_proceduret::D_UNSATISFIABLE)
result=false_exprt();
solver.pop_context();
bw_transformer=result;
bw_invariant=result;
bw_precondition=result;
}
#endif
bw_transformer=not_exprt(bw_transformer);
bw_invariant=not_exprt(bw_invariant);
bw_precondition=not_exprt(bw_precondition);
if(context_sensitive && !summary.bw_postcondition.is_true())
{
bw_transformer=implies_exprt(summary.bw_postcondition, bw_transformer);
bw_invariant=implies_exprt(summary.bw_postcondition, bw_invariant);
bw_precondition=implies_exprt(summary.bw_postcondition, bw_precondition);
}
// join // TODO: should go into summaryt
if(summary.bw_transformer.is_nil())
{
summary.bw_transformer=bw_transformer;
summary.bw_invariant=bw_invariant;
summary.bw_precondition=bw_precondition;
}
else
{
summary.bw_transformer=or_exprt(summary.bw_transformer, bw_transformer);
summary.bw_invariant=or_exprt(summary.bw_invariant, bw_invariant);
summary.bw_precondition=or_exprt(summary.bw_precondition, bw_precondition);
}
return bw_precondition;
}
