const Variable*
StatementFor::make_iteration(CGContext& cg_context, StatementAssign*& init, Expression*& test, StatementAssign*& incr, unsigned int& bound)
{
FactMgr* fm = get_fact_mgr(&cg_context);
assert(fm);
Block* blk = cg_context.get_current_block();
assert(blk);
// save a copy of facts env and context
vector<const Fact*> facts_copy = fm->global_facts;
cg_context.get_effect_stm().clear();
// Select the loop control variable, avoid volatile
vector<const Variable*> invalid_vars;
Variable *var = NULL;
do {
var = VariableSelector::SelectLoopCtrlVar(cg_context, invalid_vars);
ERROR_GUARD(NULL);
if (var->is_volatile()) {
invalid_vars.push_back(var);
} else {
break;
}
} while (true);
bool read = cg_context.read_indices(var, fm->global_facts);
assert(read);
cg_context.write_var(var);
cg_context.read_var(var);
// Select the loop parameters: init, limit, increment, etc.
int init_n, limit_n, incr_n;
eBinaryOps test_op;
eAssignOps incr_op;
bound = INVALID_BOUND;
// choose a random array from must use variables, and find the dimension with shortest length
// JYTODO: be more aggressive?
if (cg_context.rw_directive) {
vector<const Variable*> arrays;
cg_context.rw_directive->find_must_use_arrays(arrays);
if (!arrays.empty()) {
const ArrayVariable* av = dynamic_cast<const ArrayVariable*>(VariableSelector::choose_ok_var(arrays));
assert(av);
for (size_t i=0; i<av->get_dimension(); i++) {
if (av->get_sizes()[i] < bound) {
bound = av->get_sizes()[i];
}
}
}
}
if (bound != INVALID_BOUND) {
bound = make_random_array_control(--bound, init_n, limit_n, incr_n, test_op, incr_op, var->type->is_signed());
} else {
assert(var->type);
make_random_loop_control(init_n, limit_n, incr_n, test_op, incr_op, var->type->is_signed());
}
ERROR_GUARD(NULL);
// Build the IR for the subparts of the loop.
Constant * c_init = Constant::make_int(init_n);
ERROR_GUARD(NULL);
// if we chose control variable wisely, this should never return false
assert(var);
Lhs* lhs = new Lhs(*var);
ERROR_GUARD_AND_DEL1(NULL, c_init);
eBinaryOps bop = StatementAssign::compound_to_binary_ops(incr_op);
SafeOpFlags *flags1 = SafeOpFlags::make_random_binary(var->type, var->type, var->type, sOpAssign, bop);
ERROR_GUARD_AND_DEL2(NULL, c_init, lhs);
init = new StatementAssign(cg_context.get_current_block(), *lhs, *c_init, eSimpleAssign, flags1);
ERROR_GUARD_AND_DEL3(NULL, c_init, lhs, flags1);
bool visited = init->visit_facts(fm->global_facts, cg_context);
assert(visited);
assert(var);
ExpressionVariable *v = new ExpressionVariable(*var);
Bookkeeper::record_volatile_access(v->get_var(), v->get_indirect_level(), false);
Bookkeeper::record_volatile_access(v->get_var(), v->get_indirect_level(), true);
Constant *c_limit = Constant::make_int(limit_n);
ERROR_GUARD_AND_DEL2(NULL, init, v);
FunctionInvocation *invocation = FunctionInvocation::make_binary(cg_context, test_op, v, c_limit);
ERROR_GUARD_AND_DEL3(NULL, init, v, c_limit);
test = new ExpressionFuncall(*invocation);
// canonize before validation
//const ExpressionVariable exp_var(*var);
//const FunctionInvocationBinary fb(eAdd, &exp_var, c_incr);
//const ExpressionFuncall funcall(fb);
Lhs *lhs1 = dynamic_cast<Lhs*>(lhs->clone());
//SafeOpFlags *flags2 = SafeOpFlags::make_random(sOpAssign);
ERROR_GUARD_AND_DEL3(NULL, init, test, lhs1);
Constant * c_incr = Constant::make_int(incr_n);
ERROR_GUARD_AND_DEL3(NULL, init, test, lhs1);
if (bound != INVALID_BOUND) {
incr = new StatementAssign(cg_context.get_current_block(), *lhs1, *c_incr, incr_op);
} else {
incr = StatementAssign::make_possible_compound_assign(cg_context, &(v->get_type()), *lhs1, incr_op, *c_incr);
}
return var;
}
ExpressionVariable *
ExpressionVariable::make_random(CGContext &cg_context, const Type* type, const CVQualifiers* qfer, bool as_param, bool as_return)
{
DEPTH_GUARD_BY_TYPE_RETURN(dtExpressionVariable, NULL);
Function *curr_func = cg_context.get_current_func();
FactMgr* fm = get_fact_mgr_for_func(curr_func);
vector<const Variable*> dummy;
// save current effects, in case we need to reset
Effect eff_accum = cg_context.get_accum_effect();
Effect eff_stmt = cg_context.get_effect_stm();
ExpressionVariable *ev = 0;
do {
const Variable* var = 0;
// try to use one of must_read_vars in CGContext
var = VariableSelector::select_must_use_var(Effect::READ, cg_context, type, qfer);
if (var == NULL) {
var = VariableSelector::select(Effect::READ, cg_context, type, qfer, dummy, eFlexible);
}
ERROR_GUARD(NULL);
if (!var)
continue;
if (!type->is_float() && var->type->is_float())
continue;
// forbid a parameter to take the address of an argument
// this is to simplify the path shortcutting delta
if (as_param && var->is_argument() && var->type->is_dereferenced_from(type)) {
continue;
}
if (!CGOptions::addr_taken_of_locals()
&& var->type->is_dereferenced_from(type)
&& (var->is_argument() || var->is_local())) {
continue;
}
// forbid a escaping pointer to take the address of an argument or a local variable
int indirection = var->type->get_indirect_level() - type->get_indirect_level();
if (as_return && CGOptions::no_return_dead_ptr() &&
FactPointTo::is_pointing_to_locals(var, cg_context.get_current_block(), indirection, fm->global_facts)) {
continue;
}
int valid = FactPointTo::opportunistic_validate(var, type, fm->global_facts);
if (valid) {
ExpressionVariable tmp(*var, type);
if (tmp.visit_facts(fm->global_facts, cg_context)) {
ev = tmp.get_indirect_level() == 0 ? new ExpressionVariable(*var) : new ExpressionVariable(*var, type);
cg_context.curr_blk = cg_context.get_current_block();
break;
}
else {
cg_context.reset_effect_accum(eff_accum);
cg_context.reset_effect_stm(eff_stmt);
}
}
dummy.push_back(var);
} while (true);
// statistics
int deref_level = ev->get_indirect_level();
if (deref_level > 0) {
incr_counter(Bookkeeper::read_dereference_cnts, deref_level);
}
if (deref_level < 0) {
Bookkeeper::record_address_taken(ev->get_var());
}
Bookkeeper::record_volatile_access(ev->get_var(), deref_level, false);
return ev;
}