void goto_checkt::pointer_overflow_check(
const exprt &expr,
const guardt &guard)
{
if(!enable_pointer_overflow_check)
return;
if(expr.id()==ID_plus ||
expr.id()==ID_minus)
{
if(expr.operands().size()==2)
{
exprt overflow("overflow-"+expr.id_string(), bool_typet());
overflow.operands()=expr.operands();
add_guarded_claim(
not_exprt(overflow),
"pointer arithmetic overflow on "+expr.id_string(),
"overflow",
expr.find_source_location(),
expr,
guard);
}
}
}
std::string format_constantt::operator()(const exprt &expr)
{
if(expr.is_constant())
{
if(expr.type().id()==ID_natural ||
expr.type().id()==ID_integer ||
expr.type().id()==ID_unsignedbv ||
expr.type().id()==ID_signedbv)
{
mp_integer i;
if(to_integer(expr, i)) return "(number conversion failed)";
return integer2string(i);
}
else if(expr.type().id()==ID_fixedbv)
{
return fixedbvt(expr).format(*this);
}
else if(expr.type().id()==ID_floatbv)
{
return ieee_floatt(expr).format(*this);
}
}
else if(expr.id()==ID_string_constant)
return expr.get_string(ID_value);
return "(format-constant failed: "+expr.id_string()+")";
}
void arrayst::add_array_constraints(
const index_sett &index_set,
const exprt &expr)
{
if(expr.id()==ID_with)
return add_array_constraints_with(index_set, to_with_expr(expr));
else if(expr.id()==ID_if)
return add_array_constraints_if(index_set, to_if_expr(expr));
else if(expr.id()==ID_array_of)
return add_array_constraints_array_of(index_set, to_array_of_expr(expr));
else if(expr.id()==ID_symbol ||
expr.id()==ID_nondet_symbol ||
expr.id()==ID_constant ||
expr.id()=="zero_string" ||
expr.id()==ID_array ||
expr.id()==ID_string_constant)
{
}
else if(expr.id()==ID_member &&
to_member_expr(expr).struct_op().id()==ID_symbol)
{
}
else
throw "unexpected array expression: `"+expr.id_string()+"'";
}
void goto_checkt::pointer_rel_check(
const exprt &expr,
const guardt &guard)
{
if(!enable_pointer_check)
return;
if(expr.operands().size()!=2)
throw expr.id_string()+" takes two arguments";
if(expr.op0().type().id()==ID_pointer &&
expr.op1().type().id()==ID_pointer)
{
// add same-object subgoal
if(enable_pointer_check)
{
exprt same_object=::same_object(expr.op0(), expr.op1());
add_guarded_claim(
same_object,
"same object violation",
"pointer",
expr.find_source_location(),
expr,
guard);
}
}
}
void cvc_convt::convert_expr(const exprt &expr)
{
const exprt::operandst &op=expr.operands();
if(expr.id()==ID_implies)
{
if(op.size()!=2)
throw "implication takes two operands";
out << "(";
convert_expr(op[0]);
out << ") => (";
convert_expr(op[1]);
out << ")";
}
else if(expr.id()==ID_constraint_select_one)
{
if(op.size()<2)
throw "constraint_select_one takes at least two operands";
// TODO
throw "cvc_convt::convert_expr needs constraint_select_one";
}
else if(expr.id()==ID_or || expr.id()==ID_and || expr.id()==ID_xor ||
expr.id()==ID_nor || expr.id()==ID_nand)
{
if(op.empty())
throw "operator `"+expr.id_string()+"' takes at least one operand";
else if(op.size()==1)
convert_expr(op[0]);
else
{
forall_expr(it, op)
{
if(it!=op.begin())
{
if(expr.id()==ID_or)
out << " OR ";
else if(expr.id()==ID_nor)
out << " NOR ";
else if(expr.id()==ID_and)
out << " AND ";
else if(expr.id()==ID_nand)
out << " NAND ";
else if(expr.id()==ID_xor)
out << " XOR ";
else
assert(false);
}
out << "(";
convert_expr(*it);
out << ")";
}
}
}
else if(expr.id()==ID_not)
void goto_convertt::rewrite_boolean(exprt &expr)
{
assert(expr.id()==ID_and || expr.id()==ID_or);
if(!expr.is_boolean())
throw "`"+expr.id_string()+"' "
"must be Boolean, but got "+expr.pretty();
// re-write "a && b" into nested a?b:0
// re-write "a || b" into nested a?1:b
exprt tmp;
if(expr.id()==ID_and)
tmp=true_exprt();
else // ID_or
tmp=false_exprt();
exprt::operandst &ops=expr.operands();
// start with last one
for(int i=int(ops.size())-1; i>=0; i--)
{
exprt &op=ops[i];
if(!op.is_boolean())
throw "`"+expr.id_string()+"' takes Boolean "
"operands only, but got "+op.pretty();
if(expr.id()==ID_and)
{
if_exprt if_e(op, tmp, false_exprt());
tmp.swap(if_e);
}
else // ID_or
{
if_exprt if_e(op, true_exprt(), tmp);
tmp.swap(if_e);
}
}
expr.swap(tmp);
}
exprt dereferencet::dereference_rec(
const exprt &address,
const exprt &offset,
const typet &type)
{
if(address.id()==ID_address_of)
{
const address_of_exprt &address_of_expr=to_address_of_expr(address);
const exprt &object=address_of_expr.object();
return read_object(object, offset, type);
}
else if(address.id()==ID_typecast)
{
const typecast_exprt &typecast_expr=to_typecast_expr(address);
return dereference_typecast(typecast_expr, offset, type);
}
else if(address.id()==ID_plus)
{
// pointer arithmetic
if(address.operands().size()<2)
throw "plus with less than two operands";
return dereference_plus(address, offset, type);
}
else if(address.id()==ID_if)
{
const if_exprt &if_expr=to_if_expr(address);
return dereference_if(if_expr, offset, type);
}
else if(address.id()==ID_constant)
{
const typet result_type=ns.follow(address.type()).subtype();
// pointer-typed constant
if(to_constant_expr(address).get_value()==ID_NULL) // NULL
{
// we turn this into (type *)0
exprt zero=gen_zero(index_type());
return dereference_rec(
typecast_exprt(zero, address.type()), offset, type);
}
else
throw "dereferencet: unexpected pointer constant "+address.pretty();
}
else
{
throw "failed to dereference `"+address.id_string()+"'";
}
}
void goto_checkt::div_by_zero_check(const exprt &expr, const guardt &guard)
{
if (options.get_bool_option("no-div-by-zero-check"))
return;
if (expr.operands().size() != 2)
throw expr.id_string() + " takes two arguments";
// add divison by zero subgoal
exprt zero = gen_zero(expr.op1().type());
if (zero.is_nil())
throw "no zero of argument type of operator " + expr.id_string();
exprt inequality("notequal", bool_typet());
inequality.copy_to_operands(expr.op1(), zero);
add_guarded_claim(inequality, "division by zero", "division-by-zero",
expr.find_location(), guard);
}
void goto_checkt::overflow_check(const exprt &expr, const guardt &guard)
{
if (!options.get_bool_option("overflow-check"))
return;
// first, check type
if (expr.type().id() != "signedbv")
return;
// add overflow subgoal
exprt overflow("overflow-" + expr.id_string(), bool_typet());
overflow.operands() = expr.operands();
if (expr.id() == "typecast")
{
if (expr.operands().size() != 1)
throw "typecast takes one operand";
const typet &old_type = expr.op0().type();
unsigned new_width = atoi(expr.type().width().c_str());
unsigned old_width = atoi(old_type.width().c_str());
if (old_type.id() == "unsignedbv")
new_width--;
if (new_width >= old_width)
return;
overflow.id(overflow.id_string() + "-" + i2string(new_width));
}
overflow.make_not();
add_guarded_claim(overflow, "arithmetic overflow on " + expr.id_string(),
"overflow", expr.find_location(), guard);
}
void goto_checkt::pointer_rel_check(const exprt &expr, const guardt &guard)
{
if (expr.operands().size() != 2)
throw expr.id_string() + " takes one argument";
if (expr.op0().type().id() == "pointer"
&& expr.op1().type().id() == "pointer")
{
// add same-object subgoal
if (!options.get_bool_option("no-pointer-check"))
{
exprt same_object("same-object", bool_typet());
same_object.copy_to_operands(expr.op0(), expr.op1());
add_guarded_claim(same_object, "same object violation", "pointer",
expr.find_location(), guard);
}
}
}
void rd_range_domaint::assign(
const namespacet &ns,
locationt from,
const exprt &lhs,
const mp_integer &size)
{
if(lhs.id()==ID_typecast)
assign(ns, from, to_typecast_expr(lhs).op(), size);
else if(lhs.id()==ID_if)
assign_if(ns, from, to_if_expr(lhs), size);
else if(lhs.id()==ID_dereference)
assign_dereference(ns, from, to_dereference_expr(lhs), size);
else if(lhs.id()==ID_byte_extract_little_endian ||
lhs.id()==ID_byte_extract_big_endian)
assign_byte_extract(ns, from, to_byte_extract_expr(lhs), size);
else if(lhs.id()==ID_symbol ||
lhs.id()==ID_index ||
lhs.id()==ID_member)
assign(ns, from, lhs, compute_pointer_offset(ns, lhs), size);
else
throw "assignment to `"+lhs.id_string()+"' not handled";
}
void goto_checkt::nan_check(const exprt &expr, const guardt &guard)
{
if (!options.get_bool_option("nan-check"))
return;
// first, check type
if (expr.type().id() != "floatbv")
return;
if (expr.id() != "+" && expr.id() != "*" && expr.id() != "/"
&& expr.id() != "-")
return;
// add nan subgoal
exprt isnan("isnan", bool_typet());
isnan.copy_to_operands(expr);
isnan.make_not();
add_guarded_claim(isnan, "NaN on " + expr.id_string(), "NaN",
expr.find_location(), 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);
}
void goto_checkt::integer_overflow_check(
const exprt &expr,
const guardt &guard)
{
if(!enable_signed_overflow_check &&
!enable_unsigned_overflow_check)
return;
// First, check type.
const typet &type=ns.follow(expr.type());
if(type.id()==ID_signedbv && !enable_signed_overflow_check)
return;
if(type.id()==ID_unsignedbv && !enable_unsigned_overflow_check)
return;
// add overflow subgoal
if(expr.id()==ID_div)
{
assert(expr.operands().size()==2);
// undefined for signed division INT_MIN/-1
if(type.id()==ID_signedbv)
{
equal_exprt int_min_eq(
expr.op0(), to_signedbv_type(type).smallest_expr());
equal_exprt minus_one_eq(
expr.op1(), from_integer(-1, type));
add_guarded_claim(
not_exprt(and_exprt(int_min_eq, minus_one_eq)),
"arithmetic overflow on signed division",
"overflow",
expr.find_source_location(),
expr,
guard);
}
return;
}
else if(expr.id()==ID_mod)
{
// these can't overflow
return;
}
else if(expr.id()==ID_unary_minus)
{
if(type.id()==ID_signedbv)
{
// overflow on unary- can only happen with the smallest
// representable number 100....0
equal_exprt int_min_eq(
expr.op0(), to_signedbv_type(type).smallest_expr());
add_guarded_claim(
not_exprt(int_min_eq),
"arithmetic overflow on signed unary minus",
"overflow",
expr.find_source_location(),
expr,
guard);
}
return;
}
exprt overflow("overflow-"+expr.id_string(), bool_typet());
overflow.operands()=expr.operands();
if(expr.operands().size()>=3)
{
// The overflow checks are binary!
// We break these up.
for(unsigned i=1; i<expr.operands().size(); i++)
{
exprt tmp;
if(i==1)
tmp=expr.op0();
else
{
tmp=expr;
tmp.operands().resize(i);
}
overflow.operands().resize(2);
overflow.op0()=tmp;
overflow.op1()=expr.operands()[i];
std::string kind=
type.id()==ID_unsignedbv?"unsigned":"signed";
add_guarded_claim(
not_exprt(overflow),
"arithmetic overflow on "+kind+" "+expr.id_string(),
"overflow",
expr.find_source_location(),
expr,
guard);
}
}
else
{
std::string kind=
type.id()==ID_unsignedbv?"unsigned":"signed";
add_guarded_claim(
not_exprt(overflow),
"arithmetic overflow on "+kind+" "+expr.id_string(),
"overflow",
expr.find_source_location(),
expr,
guard);
}
}
void goto_checkt::check_rec(
const exprt &expr,
guardt &guard,
bool address)
{
// we don't look into quantifiers
if(expr.id()==ID_exists || expr.id()==ID_forall)
return;
if(address)
{
if(expr.id()==ID_dereference)
{
assert(expr.operands().size()==1);
check_rec(expr.op0(), guard, false);
}
else if(expr.id()==ID_index)
{
assert(expr.operands().size()==2);
check_rec(expr.op0(), guard, true);
check_rec(expr.op1(), guard, false);
}
else
{
forall_operands(it, expr)
check_rec(*it, guard, true);
}
return;
}
if(expr.id()==ID_address_of)
{
assert(expr.operands().size()==1);
check_rec(expr.op0(), guard, true);
return;
}
else if(expr.id()==ID_and || expr.id()==ID_or)
{
if(!expr.is_boolean())
throw "`"+expr.id_string()+"' must be Boolean, but got "+
expr.pretty();
guardt old_guard=guard;
for(unsigned i=0; i<expr.operands().size(); i++)
{
const exprt &op=expr.operands()[i];
if(!op.is_boolean())
throw "`"+expr.id_string()+"' takes Boolean operands only, but got "+
op.pretty();
check_rec(op, guard, false);
if(expr.id()==ID_or)
guard.add(not_exprt(op));
else
guard.add(op);
}
guard.swap(old_guard);
return;
}
else if(expr.id()==ID_if)
{
if(expr.operands().size()!=3)
throw "if takes three arguments";
if(!expr.op0().is_boolean())
{
std::string msg=
"first argument of if must be boolean, but got "
+expr.op0().pretty();
throw msg;
}
check_rec(expr.op0(), guard, false);
{
guardt old_guard=guard;
guard.add(expr.op0());
check_rec(expr.op1(), guard, false);
guard.swap(old_guard);
}
{
guardt old_guard=guard;
guard.add(not_exprt(expr.op0()));
check_rec(expr.op2(), guard, false);
guard.swap(old_guard);
}
return;
}
forall_operands(it, expr)
check_rec(*it, guard, false);
if(expr.id()==ID_index)
{
bounds_check(to_index_expr(expr), guard);
}
else if(expr.id()==ID_div)
{
div_by_zero_check(to_div_expr(expr), guard);
if(expr.type().id()==ID_signedbv)
integer_overflow_check(expr, guard);
else if(expr.type().id()==ID_floatbv)
{
nan_check(expr, guard);
float_overflow_check(expr, guard);
}
}
else if(expr.id()==ID_shl || expr.id()==ID_ashr || expr.id()==ID_lshr)
{
undefined_shift_check(to_shift_expr(expr), guard);
}
else if(expr.id()==ID_mod)
{
mod_by_zero_check(to_mod_expr(expr), guard);
}
else if(expr.id()==ID_plus || expr.id()==ID_minus ||
expr.id()==ID_mult ||
expr.id()==ID_unary_minus)
{
if(expr.type().id()==ID_signedbv ||
expr.type().id()==ID_unsignedbv)
{
if(expr.operands().size()==2 &&
expr.op0().type().id()==ID_pointer)
pointer_overflow_check(expr, guard);
else
integer_overflow_check(expr, guard);
}
else if(expr.type().id()==ID_floatbv)
{
nan_check(expr, guard);
float_overflow_check(expr, guard);
}
else if(expr.type().id()==ID_pointer)
{
pointer_overflow_check(expr, guard);
}
}
else if(expr.id()==ID_typecast)
conversion_check(expr, guard);
else if(expr.id()==ID_le || expr.id()==ID_lt ||
expr.id()==ID_ge || expr.id()==ID_gt)
pointer_rel_check(expr, guard);
else if(expr.id()==ID_dereference)
pointer_validity_check(to_dereference_expr(expr), guard);
}
value_set_dereferencet::valuet value_set_dereferencet::build_reference_to(
const exprt &what,
const modet mode,
const exprt &pointer_expr,
const guardt &guard)
{
const typet &dereference_type=
ns.follow(pointer_expr.type()).subtype();
if(what.id()==ID_unknown ||
what.id()==ID_invalid)
{
invalid_pointer(pointer_expr, guard);
return valuet();
}
if(what.id()!=ID_object_descriptor)
throw "unknown points-to: "+what.id_string();
const object_descriptor_exprt &o=to_object_descriptor_expr(what);
const exprt &root_object=o.root_object();
const exprt &object=o.object();
#if 0
std::cout << "O: " << from_expr(ns, "", root_object) << '\n';
#endif
valuet result;
if(root_object.id()=="NULL-object")
{
if(options.get_bool_option("pointer-check"))
{
guardt tmp_guard(guard);
if(o.offset().is_zero())
{
tmp_guard.add(null_pointer(pointer_expr));
dereference_callback.dereference_failure(
"pointer dereference",
"NULL pointer", tmp_guard);
}
else
{
tmp_guard.add(null_object(pointer_expr));
dereference_callback.dereference_failure(
"pointer dereference",
"NULL plus offset pointer", tmp_guard);
}
}
}
else if(root_object.id()==ID_dynamic_object)
{
// const dynamic_object_exprt &dynamic_object=
// to_dynamic_object_expr(root_object);
// the object produced by malloc
exprt malloc_object=
ns.lookup(CPROVER_PREFIX "malloc_object").symbol_expr();
exprt is_malloc_object=same_object(pointer_expr, malloc_object);
// constraint that it actually is a dynamic object
exprt dynamic_object_expr(ID_dynamic_object, bool_typet());
dynamic_object_expr.copy_to_operands(pointer_expr);
// this is also our guard
result.pointer_guard=dynamic_object_expr;
// can't remove here, turn into *p
result.value=dereference_exprt(pointer_expr, dereference_type);
if(options.get_bool_option("pointer-check"))
{
// if(!dynamic_object.valid().is_true())
{
// check if it is still alive
guardt tmp_guard(guard);
tmp_guard.add(deallocated(pointer_expr, ns));
dereference_callback.dereference_failure(
"pointer dereference",
"dynamic object deallocated",
tmp_guard);
}
if(options.get_bool_option("bounds-check"))
{
if(!o.offset().is_zero())
{
// check lower bound
guardt tmp_guard(guard);
tmp_guard.add(is_malloc_object);
tmp_guard.add(
dynamic_object_lower_bound(
pointer_expr,
ns,
nil_exprt()));
dereference_callback.dereference_failure(
"pointer dereference",
"dynamic object lower bound", tmp_guard);
}
{
// check upper bound
// we check SAME_OBJECT(__CPROVER_malloc_object, p) &&
// POINTER_OFFSET(p)+size>__CPROVER_malloc_size
guardt tmp_guard(guard);
tmp_guard.add(is_malloc_object);
tmp_guard.add(
dynamic_object_upper_bound(
pointer_expr,
dereference_type,
ns,
size_of_expr(dereference_type, ns)));
dereference_callback.dereference_failure(
"pointer dereference",
"dynamic object upper bound", tmp_guard);
}
}
}
}
else if(root_object.id()==ID_integer_address)
{
// This is stuff like *((char *)5).
// This is turned into an access to __CPROVER_memory[...].
if(language_mode==ID_java)
{
result.value=nil_exprt();
return result;
}
const symbolt &memory_symbol=ns.lookup(CPROVER_PREFIX "memory");
exprt symbol_expr=symbol_exprt(memory_symbol.name, memory_symbol.type);
if(base_type_eq(
ns.follow(memory_symbol.type).subtype(),
dereference_type, ns))
{
// Types match already, what a coincidence!
// We can use an index expression.
exprt index_expr=index_exprt(symbol_expr, pointer_offset(pointer_expr));
index_expr.type()=ns.follow(memory_symbol.type).subtype();
result.value=index_expr;
}
else if(dereference_type_compare(
ns.follow(memory_symbol.type).subtype(),
dereference_type))
{
exprt index_expr=index_exprt(symbol_expr, pointer_offset(pointer_expr));
index_expr.type()=ns.follow(memory_symbol.type).subtype();
result.value=typecast_exprt(index_expr, dereference_type);
}
else
{
// We need to use byte_extract.
// Won't do this without a commitment to an endianness.
if(config.ansi_c.endianness==configt::ansi_ct::endiannesst::NO_ENDIANNESS)
{
}
else
{
exprt byte_extract(byte_extract_id(), dereference_type);
byte_extract.copy_to_operands(
symbol_expr, pointer_offset(pointer_expr));
result.value=byte_extract;
}
}
}
else
{
// something generic -- really has to be a symbol
address_of_exprt object_pointer(object);
if(o.offset().is_zero())
{
equal_exprt equality(pointer_expr, object_pointer);
if(ns.follow(equality.lhs().type())!=ns.follow(equality.rhs().type()))
equality.lhs().make_typecast(equality.rhs().type());
result.pointer_guard=equality;
}
else
{
result.pointer_guard=same_object(pointer_expr, object_pointer);
}
guardt tmp_guard(guard);
tmp_guard.add(result.pointer_guard);
valid_check(object, tmp_guard, mode);
const typet &object_type=ns.follow(object.type());
const exprt &root_object=o.root_object();
const typet &root_object_type=ns.follow(root_object.type());
exprt root_object_subexpression=root_object;
if(dereference_type_compare(object_type, dereference_type) &&
o.offset().is_zero())
{
// The simplest case: types match, and offset is zero!
// This is great, we are almost done.
result.value=object;
if(object_type!=ns.follow(dereference_type))
result.value.make_typecast(dereference_type);
}
else if(root_object_type.id()==ID_array &&
dereference_type_compare(
root_object_type.subtype(),
dereference_type))
{
// We have an array with a subtype that matches
// the dereferencing type.
// We will require well-alignedness!
exprt offset;
// this should work as the object is essentially the root object
if(o.offset().is_constant())
offset=o.offset();
else
offset=pointer_offset(pointer_expr);
exprt adjusted_offset;
// are we doing a byte?
mp_integer element_size=
dereference_type.id()==ID_empty?
pointer_offset_size(char_type(), ns):
pointer_offset_size(dereference_type, ns);
if(element_size==1)
{
// no need to adjust offset
adjusted_offset=offset;
}
else if(element_size<=0)
{
throw "unknown or invalid type size of:\n"+dereference_type.pretty();
}
else
{
exprt element_size_expr=
from_integer(element_size, offset.type());
adjusted_offset=binary_exprt(
offset, ID_div, element_size_expr, offset.type());
// TODO: need to assert well-alignedness
}
index_exprt index_expr=
index_exprt(root_object, adjusted_offset, root_object_type.subtype());
bounds_check(index_expr, tmp_guard);
result.value=index_expr;
if(ns.follow(result.value.type())!=ns.follow(dereference_type))
result.value.make_typecast(dereference_type);
}
else if(get_subexpression_at_offset(
root_object_subexpression,
o.offset(),
dereference_type,
ns))
{
// Successfully found a member, array index, or combination thereof
// that matches the desired type and offset:
result.value=root_object_subexpression;
}
else
{
// we extract something from the root object
result.value=o.root_object();
// this is relative to the root object
const exprt offset=pointer_offset(pointer_expr);
if(memory_model(result.value, dereference_type, tmp_guard, offset))
{
// ok, done
}
else
{
if(options.get_bool_option("pointer-check"))
{
std::string msg="memory model not applicable (got `";
msg+=from_type(ns, "", result.value.type());
msg+="', expected `";
msg+=from_type(ns, "", dereference_type);
msg+="')";
dereference_callback.dereference_failure(
"pointer dereference",
msg, tmp_guard);
}
return valuet(); // give up, no way that this is ok
}
}
}
return result;
}
void arrayst::collect_arrays(const exprt &a)
{
const array_typet &array_type=
to_array_type(ns.follow(a.type()));
if(a.id()==ID_with)
{
if(a.operands().size()!=3)
throw "with expected to have three operands";
// check types
if(!base_type_eq(array_type, a.op0().type(), ns))
{
std::cout << a.pretty() << std::endl;
throw "collect_arrays got with without matching types";
}
arrays.make_union(a, a.op0());
collect_arrays(a.op0());
// make sure this shows as an application
index_exprt index_expr;
index_expr.type()=array_type.subtype();
index_expr.array()=a.op0();
index_expr.index()=a.op1();
record_array_index(index_expr);
}
else if(a.id()==ID_if)
{
if(a.operands().size()!=3)
throw "if expected to have three operands";
// check types
if(!base_type_eq(array_type, a.op1().type(), ns))
{
std::cout << a.pretty() << std::endl;
throw "collect_arrays got if without matching types";
}
// check types
if(!base_type_eq(array_type, a.op2().type(), ns))
{
std::cout << a.pretty() << std::endl;
throw "collect_arrays got if without matching types";
}
arrays.make_union(a, a.op1());
arrays.make_union(a, a.op2());
collect_arrays(a.op1());
collect_arrays(a.op2());
}
else if(a.id()==ID_symbol)
{
}
else if(a.id()==ID_nondet_symbol)
{
}
else if(a.id()==ID_member)
{
if(to_member_expr(a).struct_op().id()!=ID_symbol)
throw "unexpected array expression: member with `"+a.op0().id_string()+"'";
}
else if(a.id()==ID_constant ||
a.id()==ID_array ||
a.id()==ID_string_constant)
{
}
else if(a.id()==ID_array_of)
{
}
else
throw "unexpected array expression: `"+a.id_string()+"'";
}
void value_sett::get_value_set_rec(
const exprt &expr,
object_mapt &dest,
const std::string &suffix,
const typet &original_type,
const namespacet &ns) const
{
#if 0
std::cout << "GET_VALUE_SET_REC EXPR: " << from_expr(ns, "", expr) << "\n";
std::cout << "GET_VALUE_SET_REC SUFFIX: " << suffix << std::endl;
#endif
const typet &expr_type=ns.follow(expr.type());
if(expr.id()==ID_unknown || expr.id()==ID_invalid)
{
insert(dest, exprt(ID_unknown, original_type));
}
else if(expr.id()==ID_index)
{
assert(expr.operands().size()==2);
const typet &type=ns.follow(expr.op0().type());
assert(type.id()==ID_array ||
type.id()==ID_incomplete_array);
get_value_set_rec(expr.op0(), dest, "[]"+suffix, original_type, ns);
}
else if(expr.id()==ID_member)
{
assert(expr.operands().size()==1);
const typet &type=ns.follow(expr.op0().type());
assert(type.id()==ID_struct ||
type.id()==ID_union ||
type.id()==ID_incomplete_struct ||
type.id()==ID_incomplete_union);
const std::string &component_name=
expr.get_string(ID_component_name);
get_value_set_rec(expr.op0(), dest,
"."+component_name+suffix, original_type, ns);
}
else if(expr.id()==ID_symbol)
{
irep_idt identifier=to_symbol_expr(expr).get_identifier();
// is it a pointer, integer, array or struct?
if(expr_type.id()==ID_pointer ||
expr_type.id()==ID_signedbv ||
expr_type.id()==ID_unsignedbv ||
expr_type.id()==ID_struct ||
expr_type.id()==ID_union ||
expr_type.id()==ID_array)
{
// look it up
valuest::const_iterator v_it=
values.find(id2string(identifier)+suffix);
// try first component name as suffix if not yet found
if(v_it==values.end() &&
(expr_type.id()==ID_struct ||
expr_type.id()==ID_union))
{
const struct_union_typet &struct_union_type=
to_struct_union_type(expr_type);
const std::string first_component_name=
struct_union_type.components().front().get_string(ID_name);
v_it=values.find(
id2string(identifier)+"."+first_component_name+suffix);
}
// not found? try without suffix
if(v_it==values.end())
v_it=values.find(identifier);
if(v_it!=values.end())
make_union(dest, v_it->second.object_map);
else
insert(dest, exprt(ID_unknown, original_type));
}
else
insert(dest, exprt(ID_unknown, original_type));
}
else if(expr.id()==ID_if)
{
if(expr.operands().size()!=3)
throw "if takes three operands";
get_value_set_rec(expr.op1(), dest, suffix, original_type, ns);
get_value_set_rec(expr.op2(), dest, suffix, original_type, ns);
}
else if(expr.id()==ID_address_of)
{
if(expr.operands().size()!=1)
throw expr.id_string()+" expected to have one operand";
get_reference_set(expr.op0(), dest, ns);
}
else if(expr.id()==ID_dereference)
{
object_mapt reference_set;
get_reference_set(expr, reference_set, ns);
const object_map_dt &object_map=reference_set.read();
if(object_map.begin()==object_map.end())
insert(dest, exprt(ID_unknown, original_type));
else
{
for(object_map_dt::const_iterator
it1=object_map.begin();
it1!=object_map.end();
it1++)
{
const exprt &object=object_numbering[it1->first];
get_value_set_rec(object, dest, suffix, original_type, ns);
}
}
}
else if(expr.id()=="reference_to")
{
// old stuff, will go away
object_mapt reference_set;
get_reference_set(expr, reference_set, ns);
const object_map_dt &object_map=reference_set.read();
if(object_map.begin()==object_map.end())
insert(dest, exprt(ID_unknown, original_type));
else
{
for(object_map_dt::const_iterator
it=object_map.begin();
it!=object_map.end();
it++)
{
const exprt &object=object_numbering[it->first];
get_value_set_rec(object, dest, suffix, original_type, ns);
}
}
}
else if(expr.is_constant())
{
// check if NULL
if(expr.get(ID_value)==ID_NULL &&
expr_type.id()==ID_pointer)
{
insert(dest, exprt("NULL-object", expr_type.subtype()), 0);
}
else if(expr_type.id()==ID_unsignedbv ||
expr_type.id()==ID_signedbv)
{
// an integer constant got turned into a pointer
insert(dest, exprt(ID_integer_address, unsigned_char_type()));
}
else
insert(dest, exprt(ID_unknown, original_type));
}
else if(expr.id()==ID_typecast)
{
if(expr.operands().size()!=1)
throw "typecast takes one operand";
// let's see what gets converted to what
const typet &op_type=ns.follow(expr.op0().type());
if(op_type.id()==ID_pointer)
{
// pointer-to-pointer -- we just ignore these
get_value_set_rec(expr.op0(), dest, suffix, original_type, ns);
}
else if(op_type.id()==ID_unsignedbv ||
op_type.id()==ID_signedbv)
{
// integer-to-pointer
if(expr.op0().is_zero())
insert(dest, exprt("NULL-object", expr_type.subtype()), 0);
else
{
// see if we have something for the integer
object_mapt tmp;
get_value_set_rec(expr.op0(), tmp, suffix, original_type, ns);
if(tmp.read().size()==0)
{
// if not, throw in integer
insert(dest, exprt(ID_integer_address, unsigned_char_type()));
}
else if(tmp.read().size()==1 &&
object_numbering[tmp.read().begin()->first].id()==ID_unknown)
{
// if not, throw in integer
insert(dest, exprt(ID_integer_address, unsigned_char_type()));
}
else
{
// use as is
dest.write().insert(tmp.read().begin(), tmp.read().end());
}
}
}
else
insert(dest, exprt(ID_unknown, original_type));
}
else if(expr.id()==ID_plus ||
expr.id()==ID_minus)
{
if(expr.operands().size()<2)
throw expr.id_string()+" expected to have at least two operands";
object_mapt pointer_expr_set;
mp_integer i;
bool i_is_set=false;
// special case for pointer+integer
if(expr.operands().size()==2 &&
expr_type.id()==ID_pointer)
{
exprt ptr_operand;
if(expr.op0().type().id()!=ID_pointer &&
expr.op0().is_constant())
{
i_is_set=!to_integer(expr.op0(), i);
ptr_operand=expr.op1();
}
else
{
i_is_set=!to_integer(expr.op1(), i);
ptr_operand=expr.op0();
}
if(i_is_set)
{
i*=pointer_offset_size(ptr_operand.type().subtype(), ns);
if(expr.id()==ID_minus) i.negate();
}
get_value_set_rec(
ptr_operand, pointer_expr_set, "", ptr_operand.type(), ns);
}
else
{
// we get the points-to for all operands, even integers
forall_operands(it, expr)
{
get_value_set_rec(
*it, pointer_expr_set, "", it->type(), ns);
}
}
for(object_map_dt::const_iterator
it=pointer_expr_set.read().begin();
it!=pointer_expr_set.read().end();
it++)
{
objectt object=it->second;
// adjust by offset
if(object.offset_is_zero() && i_is_set)
object.offset=i;
else
object.offset_is_set=false;
insert(dest, it->first, object);
}
}
void local_SSAt::assign_rec(
const exprt &lhs,
const exprt &rhs,
const exprt &guard,
locationt loc)
{
const typet &type=ns.follow(lhs.type());
if(is_symbol_struct_member(lhs, ns))
{
if(type.id()==ID_struct)
{
// need to split up
const struct_typet &struct_type=to_struct_type(type);
const struct_typet::componentst &components=struct_type.components();
for(struct_typet::componentst::const_iterator
it=components.begin();
it!=components.end();
it++)
{
member_exprt new_lhs(lhs, it->get_name(), it->type());
member_exprt new_rhs(rhs, it->get_name(), it->type());
assign_rec(new_lhs, new_rhs, guard, loc);
}
return;
}
ssa_objectt lhs_object(lhs, ns);
const std::set<ssa_objectt> &assigned=
assignments.get(loc);
if(assigned.find(lhs_object)!=assigned.end())
{
exprt ssa_rhs=read_rhs(rhs, loc);
const symbol_exprt ssa_symbol=name(lhs_object, OUT, loc);
equal_exprt equality(ssa_symbol, ssa_rhs);
nodes[loc].equalities.push_back(equality);
}
}
else if(lhs.id()==ID_index)
{
const index_exprt &index_expr=to_index_expr(lhs);
exprt ssa_array=index_expr.array();
exprt new_rhs=with_exprt(ssa_array, index_expr.index(), rhs);
assign_rec(index_expr.array(), new_rhs, guard, loc);
}
else if(lhs.id()==ID_member)
{
// These are non-flattened struct or union members.
const member_exprt &member_expr=to_member_expr(lhs);
const exprt &compound=member_expr.struct_op();
const typet &compound_type=ns.follow(compound.type());
if(compound_type.id()==ID_union)
{
union_exprt new_rhs(member_expr.get_component_name(), rhs, compound.type());
assign_rec(member_expr.struct_op(), new_rhs, guard, loc);
}
else if(compound_type.id()==ID_struct)
{
exprt member_name(ID_member_name);
member_name.set(ID_component_name, member_expr.get_component_name());
with_exprt new_rhs(compound, member_name, rhs);
assign_rec(compound, new_rhs, guard, loc);
}
}
else if(lhs.id()==ID_complex_real)
{
assert(lhs.operands().size()==1);
const exprt &op=lhs.op0();
const complex_typet &complex_type=to_complex_type(op.type());
exprt imag_op=unary_exprt(ID_complex_imag, op, complex_type.subtype());
complex_exprt new_rhs(rhs, imag_op, complex_type);
assign_rec(op, new_rhs, guard, loc);
}
else if(lhs.id()==ID_complex_imag)
{
assert(lhs.operands().size()==1);
const exprt &op=lhs.op0();
const complex_typet &complex_type=to_complex_type(op.type());
exprt real_op=unary_exprt(ID_complex_real, op, complex_type.subtype());
complex_exprt new_rhs(real_op, rhs, complex_type);
assign_rec(op, new_rhs, guard, loc);
}
else if(lhs.id()==ID_if)
{
const if_exprt &if_expr=to_if_expr(lhs);
assign_rec(if_expr.true_case(), rhs, and_exprt(guard, if_expr.cond()), loc);
assign_rec(if_expr.false_case(), rhs, and_exprt(guard, not_exprt(if_expr.cond())), loc);
}
else if(lhs.id()==ID_byte_extract_little_endian ||
lhs.id()==ID_byte_extract_big_endian)
{
const byte_extract_exprt &byte_extract_expr=to_byte_extract_expr(lhs);
exprt new_lhs=byte_extract_expr.op();
exprt new_rhs=byte_extract_exprt(
byte_extract_expr.id(), rhs, byte_extract_expr.offset(), new_lhs.type());
assign_rec(new_lhs, new_rhs, guard, loc);
}
else
throw "UNKNOWN LHS: "+lhs.id_string();
}
void goto_checkt::check_rec(const exprt &expr, guardt &guard, bool address)
{
if (address)
{
if (expr.id() == "dereference")
{
assert(expr.operands().size() == 1);
check_rec(expr.op0(), guard, false);
}
else if (expr.id() == "index")
{
assert(expr.operands().size() == 2);
check_rec(expr.op0(), guard, true);
check_rec(expr.op1(), guard, false);
}
else
{
forall_operands(it, expr)
check_rec(*it, guard, true);
}
return;
}
if (expr.is_address_of())
{
assert(expr.operands().size() == 1);
check_rec(expr.op0(), guard, true);
return;
}
else if (expr.is_and() || expr.id() == "or")
{
if (!expr.is_boolean())
throw expr.id_string() + " must be Boolean, but got " + expr.pretty();
unsigned old_guards = guard.size();
for (unsigned i = 0; i < expr.operands().size(); i++)
{
const exprt &op = expr.operands()[i];
if (!op.is_boolean())
throw expr.id_string() + " takes Boolean operands only, but got "
+ op.pretty();
check_rec(op, guard, false);
if (expr.id() == "or")
{
exprt tmp(op);
tmp.make_not();
expr2tc tmp_expr;
migrate_expr(tmp, tmp_expr);
guard.move(tmp_expr);
}
else
{
expr2tc tmp;
migrate_expr(op, tmp);
guard.add(tmp);
}
}
guard.resize(old_guards);
return;
}
else if (expr.id() == "if")
{
if (expr.operands().size() != 3)
throw "if takes three arguments";
if (!expr.op0().is_boolean())
{
std::string msg = "first argument of if must be boolean, but got "
+ expr.op0().to_string();
throw msg;
}
check_rec(expr.op0(), guard, false);
{
unsigned old_guard = guard.size();
expr2tc tmp;
migrate_expr(expr.op0(), tmp);
guard.add(tmp);
check_rec(expr.op1(), guard, false);
guard.resize(old_guard);
}
{
unsigned old_guard = guard.size();
exprt tmp(expr.op0());
tmp.make_not();
expr2tc tmp_expr;
migrate_expr(tmp, tmp_expr);
guard.move(tmp_expr);
check_rec(expr.op2(), guard, false);
guard.resize(old_guard);
}
return;
}
forall_operands(it, expr)
check_rec(*it, guard, false);
if (expr.id() == "index")
{
bounds_check(expr, guard);
}
else if (expr.id() == "/")
{
div_by_zero_check(expr, guard);
if (expr.type().id() == "signedbv")
{
overflow_check(expr, guard);
}
else if (expr.type().id() == "floatbv")
{
nan_check(expr, guard);
}
}
else if (expr.id() == "+" || expr.id() == "-" || expr.id() == "*"
|| expr.id() == "unary-" || expr.id() == "typecast")
{
if (expr.type().id() == "signedbv")
{
overflow_check(expr, guard);
}
else if (expr.type().id() == "floatbv")
{
nan_check(expr, guard);
}
}
else if (expr.id() == "<=" || expr.id() == "<" || expr.id() == ">="
|| expr.id() == ">")
{
pointer_rel_check(expr, guard);
}
else if (expr.id() == "mod")
{
div_by_zero_check(expr, guard);
if (expr.type().id() == "signedbv")
{
overflow_check(expr, guard);
}
else if (expr.type().id() == "floatbv")
{
nan_check(expr, guard);
}
}
}
void goto_program_dereferencet::dereference_rec(
exprt &expr,
guardt &guard,
const value_set_dereferencet::modet mode)
{
if(!dereference.has_dereference(expr))
return;
if(expr.id()==ID_and || expr.id()==ID_or)
{
if(!expr.is_boolean())
throw expr.id_string()+" must be Boolean, but got "+
expr.pretty();
guardt old_guard=guard;
for(unsigned i=0; i<expr.operands().size(); i++)
{
exprt &op=expr.operands()[i];
if(!op.is_boolean())
throw expr.id_string()+" takes Boolean operands only, but got "+
op.pretty();
if(dereference.has_dereference(op))
dereference_rec(op, guard, value_set_dereferencet::modet::READ);
if(expr.id()==ID_or)
{
exprt tmp(op);
tmp.make_not();
guard.add(tmp);
}
else
guard.add(op);
}
guard.swap(old_guard);
return;
}
else if(expr.id()==ID_if)
{
if(expr.operands().size()!=3)
throw "if takes three arguments";
if(!expr.op0().is_boolean())
{
std::string msg=
"first argument of if must be boolean, but got "
+expr.op0().pretty();
throw msg;
}
dereference_rec(expr.op0(), guard, value_set_dereferencet::modet::READ);
bool o1=dereference.has_dereference(expr.op1());
bool o2=dereference.has_dereference(expr.op2());
if(o1)
{
guardt old_guard=guard;
guard.add(expr.op0());
dereference_rec(expr.op1(), guard, mode);
guard.swap(old_guard);
}
if(o2)
{
guardt old_guard=guard;
exprt tmp(expr.op0());
tmp.make_not();
guard.add(tmp);
dereference_rec(expr.op2(), guard, mode);
guard.swap(old_guard);
}
return;
}
if(expr.id()==ID_address_of ||
expr.id()=="reference_to")
{
// turn &*p to p
// this has *no* side effect!
assert(expr.operands().size()==1);
if(expr.op0().id()==ID_dereference)
{
assert(expr.op0().operands().size()==1);
exprt tmp;
tmp.swap(expr.op0().op0());
if(tmp.type()!=expr.type())
tmp.make_typecast(expr.type());
expr.swap(tmp);
}
}
Forall_operands(it, expr)
dereference_rec(*it, guard, mode);
if(expr.id()==ID_dereference)
{
if(expr.operands().size()!=1)
throw "dereference expects one operand";
dereference_location=expr.find_source_location();
exprt tmp=dereference.dereference(
expr.op0(), guard, mode);
expr.swap(tmp);
}
else if(expr.id()==ID_index)
{
// this is old stuff and will go away
if(expr.operands().size()!=2)
throw "index expects two operands";
if(expr.op0().type().id()==ID_pointer)
{
dereference_location=expr.find_source_location();
exprt tmp1(ID_plus, expr.op0().type());
tmp1.operands().swap(expr.operands());
exprt tmp2=dereference.dereference(tmp1, guard, mode);
tmp2.swap(expr);
}
}
}
void goto_inlinet::expand_function_call(
goto_programt &dest,
goto_programt::targett &target,
const exprt &lhs,
const exprt &function,
const exprt::operandst &arguments,
const exprt &constrain,
bool full)
{
// look it up
if(function.id()!="symbol")
{
err_location(function);
throw "function_call expects symbol as function operand, "
"but got `"+function.id_string()+"'";
}
const irep_idt &identifier=function.identifier();
// see if we are already expanding it
if(recursion_set.find(identifier)!=recursion_set.end())
{
if(!full)
{
target++;
return; // simply ignore, we don't do full inlining, it's ok
}
// it's really recursive. Uh. Buh. Give up.
err_location(function);
warning("recursion is ignored");
target->make_skip();
target++;
return;
}
goto_functionst::function_mapt::iterator m_it=
goto_functions.function_map.find(identifier);
if(m_it==goto_functions.function_map.end())
{
err_location(function);
str << "failed to find function `" << identifier
<< "'";
throw 0;
}
goto_functiont &f=m_it->second;
// see if we need to inline this
if(!full)
{
if(!f.body_available ||
(!f.is_inlined() && f.body.instructions.size() > smallfunc_limit))
{
target++;
return;
}
}
if(f.body_available)
{
inlined_funcs.insert(identifier.as_string());
for (std::set<std::string>::const_iterator it2 = f.inlined_funcs.begin();
it2 != f.inlined_funcs.end(); it2++) {
inlined_funcs.insert(*it2);
}
recursion_sett::iterator recursion_it=
recursion_set.insert(identifier).first;
goto_programt tmp2;
tmp2.copy_from(f.body);
assert(tmp2.instructions.back().is_end_function());
tmp2.instructions.back().type=LOCATION;
replace_return(tmp2, lhs, constrain);
goto_programt tmp;
parameter_assignments(tmp2.instructions.front().location, f.type, arguments, tmp);
tmp.destructive_append(tmp2);
// set local variables
Forall_goto_program_instructions(it, tmp)
it->local_variables.insert(target->local_variables.begin(),
target->local_variables.end());
if(f.type.hide())
{
const locationt &new_location=function.find_location();
Forall_goto_program_instructions(it, tmp)
{
if(new_location.is_not_nil())
{
// can't just copy, e.g., due to comments field
it->location.id(""); // not NIL
it->location.set_file(new_location.get_file());
it->location.set_line(new_location.get_line());
it->location.set_column(new_location.get_column());
it->location.set_function(new_location.get_function());
}
}
}
// do this recursively
goto_inline_rec(tmp, full);
// set up location instruction for function call
target->type=LOCATION;
target->code = expr2tc();
goto_programt::targett next_target(target);
next_target++;
dest.instructions.splice(next_target, tmp.instructions);
target=next_target;
recursion_set.erase(recursion_it);
}
void boolbvt::convert_add_sub(const exprt &expr, bvt &bv)
{
const typet &type=ns.follow(expr.type());
if(type.id()!=ID_unsignedbv &&
type.id()!=ID_signedbv &&
type.id()!=ID_fixedbv &&
type.id()!=ID_floatbv &&
type.id()!=ID_range &&
type.id()!=ID_vector)
return conversion_failed(expr, bv);
unsigned width=boolbv_width(type);
if(width==0)
return conversion_failed(expr, bv);
const exprt::operandst &operands=expr.operands();
if(operands.size()==0)
throw "operand "+expr.id_string()+" takes at least one operand";
const exprt &op0=expr.op0();
if(op0.type()!=type)
{
std::cerr << expr.pretty() << std::endl;
throw "add/sub with mixed types";
}
convert_bv(op0, bv);
if(bv.size()!=width)
throw "convert_add_sub: unexpected operand 0 width";
bool subtract=(expr.id()==ID_minus ||
expr.id()=="no-overflow-minus");
bool no_overflow=(expr.id()=="no-overflow-plus" ||
expr.id()=="no-overflow-minus");
typet arithmetic_type=
(type.id()==ID_vector)?ns.follow(type.subtype()):type;
bv_utilst::representationt rep=
(arithmetic_type.id()==ID_signedbv ||
arithmetic_type.id()==ID_fixedbv)?bv_utilst::SIGNED:
bv_utilst::UNSIGNED;
for(exprt::operandst::const_iterator
it=operands.begin()+1;
it!=operands.end(); it++)
{
if(it->type()!=type)
{
std::cerr << expr.pretty() << std::endl;
throw "add/sub with mixed types";
}
bvt op;
convert_bv(*it, op);
if(op.size()!=width)
throw "convert_add_sub: unexpected operand width";
if(type.id()==ID_vector)
{
const typet &subtype=ns.follow(type.subtype());
unsigned sub_width=boolbv_width(subtype);
if(sub_width==0 || width%sub_width!=0)
throw "convert_add_sub: unexpected vector operand width";
unsigned size=width/sub_width;
bv.resize(width);
for(unsigned i=0; i<size; i++)
{
bvt tmp_op;
tmp_op.resize(sub_width);
for(unsigned j=0; j<tmp_op.size(); j++)
{
assert(i*sub_width+j<op.size());
tmp_op[j]=op[i*sub_width+j];
}
bvt tmp_result;
tmp_result.resize(sub_width);
for(unsigned j=0; j<tmp_result.size(); j++)
{
assert(i*sub_width+j<bv.size());
tmp_result[j]=bv[i*sub_width+j];
}
if(type.subtype().id()==ID_floatbv)
{
#ifdef HAVE_FLOATBV
float_utilst float_utils(prop);
float_utils.spec=to_floatbv_type(subtype);
tmp_result=float_utils.add_sub(tmp_result, tmp_op, subtract);
#else
return conversion_failed(expr, bv);
#endif
}
else
tmp_result=bv_utils.add_sub(tmp_result, tmp_op, subtract);
assert(tmp_result.size()==sub_width);
for(unsigned j=0; j<tmp_result.size(); j++)
{
assert(i*sub_width+j<bv.size());
bv[i*sub_width+j]=tmp_result[j];
}
}
}
else if(type.id()==ID_floatbv)
{
#ifdef HAVE_FLOATBV
float_utilst float_utils(prop);
float_utils.spec=to_floatbv_type(arithmetic_type);
bv=float_utils.add_sub(bv, op, subtract);
#else
return conversion_failed(expr, bv);
#endif
}
else if(no_overflow)
bv=bv_utils.add_sub_no_overflow(bv, op, subtract, rep);
else
bv=bv_utils.add_sub(bv, op, subtract);
}
}
void abstract_expression(
const predicatest &predicates,
exprt &expr,
const namespacet &ns)
{
if(expr.type().id()!=ID_bool)
throw "abstract_expression expects expression of type Boolean";
simplify(expr, ns);
if(is_valid(expr, ns))
{
// If expr is valid, we can abstract it as 'true'
expr.make_true();
} else if(is_unsatisfiable(expr, ns))
{
// If expr is unsatisfiable, we can abstract it as 'false'
expr.make_false();
} else if(expr.id()==ID_and || expr.id()==ID_or ||
expr.id()==ID_implies || expr.id()==ID_xor)
{
Forall_operands(it, expr)
abstract_expression(predicates, *it, ns);
}
else if(expr.id()==ID_not)
{
assert(expr.operands().size()==1);
abstract_expression(predicates, expr.op0(), ns);
// remove double negation
if(expr.op0().id()==ID_not &&
expr.op0().operands().size()==1)
{
exprt tmp;
tmp.swap(expr.op0().op0());
expr.swap(tmp);
}
}
else if(expr.id()==ID_if)
{
assert(expr.operands().size()==3);
Forall_operands(it, expr)
abstract_expression(predicates, *it, ns);
exprt true_expr(ID_and, bool_typet());
true_expr.copy_to_operands(expr.op0(), expr.op1());
exprt false_expr(ID_and, bool_typet());
false_expr.copy_to_operands(gen_not(expr.op0()), expr.op2());
exprt or_expr(ID_or, bool_typet());
or_expr.move_to_operands(true_expr, false_expr);
expr.swap(or_expr);
}
else if(expr.id()==ID_equal || expr.id()==ID_notequal)
{
if(expr.operands().size()!=2)
throw expr.id_string()+" takes two operands";
// Is it equality on Booleans?
if(expr.op0().type().id()==ID_bool &&
expr.op1().type().id()==ID_bool)
{
// leave it in
Forall_operands(it, expr)
abstract_expression(predicates, *it, ns);
}
else // other types, make it a predicate
{
if(has_non_boolean_if(expr))
{
lift_if(expr);
abstract_expression(predicates, expr, ns);
}
else
make_it_a_predicate(predicates, expr, ns);
}
}
else if(expr.is_constant())
{
// leave it as is
}
else if(has_non_boolean_if(expr))
{
lift_if(expr);
abstract_expression(predicates, expr, ns);
}
else
{
make_it_a_predicate(predicates, expr, ns);
}
}
void cvc_convt::convert_address_of_rec(const exprt &expr)
{
if(expr.id()==ID_symbol ||
expr.id()==ID_constant ||
expr.id()==ID_string_constant)
{
out
<< "(# object:="
<< pointer_logic.add_object(expr)
<< ", offset:="
<< bin_zero(config.ansi_c.pointer_width) << " #)";
}
else if(expr.id()==ID_index)
{
if(expr.operands().size()!=2)
throw "index takes two operands";
const exprt &array=expr.op0();
const exprt &index=expr.op1();
if(index.is_zero())
{
if(array.type().id()==ID_pointer)
convert_expr(array);
else if(array.type().id()==ID_array)
convert_address_of_rec(array);
else
assert(false);
}
else
{
out << "(LET P: ";
out << cvc_pointer_type();
out << " = ";
if(array.type().id()==ID_pointer)
convert_expr(array);
else if(array.type().id()==ID_array)
convert_address_of_rec(array);
else
assert(false);
out << " IN P WITH .offset:=BVPLUS("
<< config.ansi_c.pointer_width
<< ", P.offset, ";
convert_expr(index);
out << "))";
}
}
else if(expr.id()==ID_member)
{
if(expr.operands().size()!=1)
throw "member takes one operand";
const exprt &struct_op=expr.op0();
out << "(LET P: ";
out << cvc_pointer_type();
out << " = ";
convert_address_of_rec(struct_op);
const irep_idt &component_name=
to_member_expr(expr).get_component_name();
mp_integer offset=member_offset(
to_struct_type(struct_op.type()),
component_name, ns);
typet index_type(ID_unsignedbv);
index_type.set(ID_width, config.ansi_c.pointer_width);
exprt index=from_integer(offset, index_type);
out << " IN P WITH .offset:=BVPLUS("
<< config.ansi_c.pointer_width
<< ", P.offset, ";
convert_expr(index);
out << "))";
}
else
throw "don't know how to take address of: "+expr.id_string();
}
void boolbvt::convert_floatbv_op(const exprt &expr, bvt &bv)
{
const exprt::operandst &operands=expr.operands();
if(operands.size()!=3)
throw "operator "+expr.id_string()+" takes three operands";
const exprt &op0=expr.op0(); // first operand
const exprt &op1=expr.op1(); // second operand
const exprt &op2=expr.op2(); // rounding mode
bvt bv0=convert_bv(op0);
bvt bv1=convert_bv(op1);
bvt bv2=convert_bv(op2);
const typet &type=ns.follow(expr.type());
if(op0.type()!=type || op1.type()!=type)
{
std::cerr << expr.pretty() << std::endl;
throw "float op with mixed types";
}
float_utilst float_utils(prop);
float_utils.set_rounding_mode(bv2);
if(type.id()==ID_floatbv)
{
float_utils.spec=to_floatbv_type(expr.type());
if(expr.id()==ID_floatbv_plus)
bv=float_utils.add_sub(bv0, bv1, false);
else if(expr.id()==ID_floatbv_minus)
bv=float_utils.add_sub(bv0, bv1, true);
else if(expr.id()==ID_floatbv_mult)
bv=float_utils.mul(bv0, bv1);
else if(expr.id()==ID_floatbv_div)
bv=float_utils.div(bv0, bv1);
else if(expr.id()==ID_floatbv_rem)
bv=float_utils.rem(bv0, bv1);
else
assert(false);
}
else if(type.id()==ID_vector || type.id()==ID_complex)
{
const typet &subtype=ns.follow(type.subtype());
if(subtype.id()==ID_floatbv)
{
float_utils.spec=to_floatbv_type(subtype);
std::size_t width=boolbv_width(type);
std::size_t sub_width=boolbv_width(subtype);
if(sub_width==0 || width%sub_width!=0)
throw "convert_floatbv_op: unexpected vector operand width";
std::size_t size=width/sub_width;
bv.resize(width);
for(std::size_t i=0; i<size; i++)
{
bvt tmp_bv0, tmp_bv1, tmp_bv;
tmp_bv0.assign(bv0.begin()+i*sub_width, bv0.begin()+(i+1)*sub_width);
tmp_bv1.assign(bv1.begin()+i*sub_width, bv1.begin()+(i+1)*sub_width);
if(expr.id()==ID_floatbv_plus)
tmp_bv=float_utils.add_sub(tmp_bv0, tmp_bv1, false);
else if(expr.id()==ID_floatbv_minus)
tmp_bv=float_utils.add_sub(tmp_bv0, tmp_bv1, true);
else if(expr.id()==ID_floatbv_mult)
tmp_bv=float_utils.mul(tmp_bv0, tmp_bv1);
else if(expr.id()==ID_floatbv_div)
tmp_bv=float_utils.div(tmp_bv0, tmp_bv1);
else
assert(false);
assert(tmp_bv.size()==sub_width);
assert(i*sub_width+sub_width-1<bv.size());
std::copy(tmp_bv.begin(), tmp_bv.end(), bv.begin()+i*sub_width);
}
}
else
return conversion_failed(expr, bv);
}
else
return conversion_failed(expr, bv);
}
literalt boolbvt::convert_overflow(const exprt &expr)
{
const exprt::operandst &operands=expr.operands();
if(expr.id()==ID_overflow_plus ||
expr.id()==ID_overflow_minus)
{
if(operands.size()!=2)
throw "operator "+expr.id_string()+" takes two operands";
const bvt &bv0=convert_bv(operands[0]);
const bvt &bv1=convert_bv(operands[1]);
if(bv0.size()!=bv1.size())
return SUB::convert_rest(expr);
bv_utilst::representationt rep=
expr.op0().type().id()==ID_signedbv?bv_utilst::SIGNED:
bv_utilst::UNSIGNED;
return expr.id()==ID_overflow_minus?
bv_utils.overflow_sub(bv0, bv1, rep):
bv_utils.overflow_add(bv0, bv1, rep);
}
else if(expr.id()==ID_overflow_mult)
{
if(operands.size()!=2)
throw "operator "+expr.id_string()+" takes two operands";
if(operands[0].type().id()!=ID_unsignedbv &&
operands[0].type().id()!=ID_signedbv)
return SUB::convert_rest(expr);
bvt bv0=convert_bv(operands[0]);
bvt bv1=convert_bv(operands[1]);
if(bv0.size()!=bv1.size())
throw "operand size mismatch on overflow-*";
bv_utilst::representationt rep=
operands[0].type().id()==ID_signedbv?bv_utilst::SIGNED:
bv_utilst::UNSIGNED;
if(operands[0].type()!=operands[1].type())
throw "operand type mismatch on overflow-*";
assert(bv0.size()==bv1.size());
unsigned old_size=bv0.size();
unsigned new_size=old_size*2;
// sign/zero extension
bv0=bv_utils.extension(bv0, new_size, rep);
bv1=bv_utils.extension(bv1, new_size, rep);
bvt result=bv_utils.multiplier(bv0, bv1, rep);
if(rep==bv_utilst::UNSIGNED)
{
bvt bv_overflow;
bv_overflow.reserve(old_size);
// get top result bits
for(unsigned i=old_size; i<result.size(); i++)
bv_overflow.push_back(result[i]);
return prop.lor(bv_overflow);
}
else
{
bvt bv_overflow;
bv_overflow.reserve(old_size);
// get top result bits, plus one more
assert(old_size!=0);
for(unsigned i=old_size-1; i<result.size(); i++)
bv_overflow.push_back(result[i]);
// these need to be either all 1's or all 0's
literalt all_one=prop.land(bv_overflow);
literalt all_zero=prop.lnot(prop.lor(bv_overflow));
return prop.lnot(prop.lor(all_one, all_zero));
}
}
else if(expr.id()==ID_overflow_unary_minus)
{
if(operands.size()!=1)
throw "operator "+expr.id_string()+" takes one operand";
const bvt &bv=convert_bv(operands[0]);
return bv_utils.overflow_negate(bv);
}
else if(has_prefix(expr.id_string(), "overflow-typecast-"))
{
unsigned bits=atoi(expr.id().c_str()+18);
const exprt::operandst &operands=expr.operands();
if(operands.size()!=1)
throw "operator "+expr.id_string()+" takes one operand";
const exprt &op=operands[0];
const bvt &bv=convert_bv(op);
if(bits>=bv.size() || bits==0)
throw "overflow-typecast got wrong number of bits";
// signed or unsigned?
if(op.type().id()==ID_signedbv)
{
bvt tmp_bv;
for(unsigned i=bits; i<bv.size(); i++)
tmp_bv.push_back(prop.lxor(bv[bits-1], bv[i]));
return prop.lor(tmp_bv);
}
else
{
bvt tmp_bv;
for(unsigned i=bits; i<bv.size(); i++)
tmp_bv.push_back(bv[i]);
return prop.lor(tmp_bv);
}
}
return SUB::convert_rest(expr);
}
exprt goto_symext::address_arithmetic(
const exprt &expr,
statet &state,
guardt &guard,
bool keep_array)
{
exprt result;
if(expr.id()==ID_byte_extract_little_endian ||
expr.id()==ID_byte_extract_big_endian)
{
// address_of(byte_extract(op, offset, t)) is
// address_of(op) + offset with adjustments for arrays
const byte_extract_exprt &be=to_byte_extract_expr(expr);
// recursive call
result=address_arithmetic(be.op(), state, guard, keep_array);
if(ns.follow(be.op().type()).id()==ID_array &&
result.id()==ID_address_of)
{
address_of_exprt &a=to_address_of_expr(result);
// turn &a of type T[i][j] into &(a[0][0])
for(const typet *t=&(ns.follow(a.type().subtype()));
t->id()==ID_array && !base_type_eq(expr.type(), *t, ns);
t=&(ns.follow(*t).subtype()))
a.object()=index_exprt(a.object(), from_integer(0, index_type()));
}
// do (expr.type() *)(((char *)op)+offset)
result=typecast_exprt(result, pointer_typet(char_type()));
// there could be further dereferencing in the offset
exprt offset=be.offset();
dereference_rec(offset, state, guard, false);
result=plus_exprt(result, offset);
// treat &array as &array[0]
const typet &expr_type=ns.follow(expr.type());
pointer_typet dest_type;
if(expr_type.id()==ID_array && !keep_array)
dest_type.subtype()=expr_type.subtype();
else
dest_type.subtype()=expr_type;
result=typecast_exprt(result, dest_type);
}
else if(expr.id()==ID_index ||
expr.id()==ID_member)
{
object_descriptor_exprt ode;
ode.build(expr, ns);
byte_extract_exprt be(byte_extract_id());
be.type()=expr.type();
be.op()=ode.root_object();
be.offset()=ode.offset();
// recursive call
result=address_arithmetic(be, state, guard, keep_array);
do_simplify(result);
}
else if(expr.id()==ID_dereference)
{
// ANSI-C guarantees &*p == p no matter what p is,
// even if it's complete garbage
// just grab the pointer, but be wary of further dereferencing
// in the pointer itself
result=to_dereference_expr(expr).pointer();
dereference_rec(result, state, guard, false);
}
else if(expr.id()==ID_if)
{
if_exprt if_expr=to_if_expr(expr);
// the condition is not an address
dereference_rec(if_expr.cond(), state, guard, false);
// recursive call
if_expr.true_case()=
address_arithmetic(if_expr.true_case(), state, guard, keep_array);
if_expr.false_case()=
address_arithmetic(if_expr.false_case(), state, guard, keep_array);
result=if_expr;
}
else if(expr.id()==ID_symbol ||
expr.id()==ID_string_constant ||
expr.id()==ID_label ||
expr.id()==ID_array)
{
// give up, just dereference
result=expr;
dereference_rec(result, state, guard, false);
// turn &array into &array[0]
if(ns.follow(result.type()).id()==ID_array && !keep_array)
result=index_exprt(result, from_integer(0, index_type()));
// handle field-sensitive SSA symbol
mp_integer offset=0;
if(expr.id()==ID_symbol &&
expr.get_bool(ID_C_SSA_symbol))
{
offset=compute_pointer_offset(expr, ns);
assert(offset>=0);
}
if(offset>0)
{
byte_extract_exprt be(byte_extract_id());
be.type()=expr.type();
be.op()=to_ssa_expr(expr).get_l1_object();
be.offset()=from_integer(offset, index_type());
result=address_arithmetic(be, state, guard, keep_array);
do_simplify(result);
}
else
result=address_of_exprt(result);
}
else
throw "goto_symext::address_arithmetic does not handle "+expr.id_string();
const typet &expr_type=ns.follow(expr.type());
assert((expr_type.id()==ID_array && !keep_array) ||
base_type_eq(pointer_typet(expr_type), result.type(), ns));
return result;
}
