/*
* Check, if the value of a node cannot represent a NULL pointer.
*
* - Sels are skipped
* - A SymConst(entity) is NEVER a NULL pointer
* - Confirms are evaluated
*/
int value_not_null(const ir_node *n, const ir_node **confirm)
{
ir_tarval *tv;
*confirm = NULL;
tv = value_of(n);
if (tarval_is_constant(tv) && ! tarval_is_null(tv))
return 1;
assert(mode_is_reference(get_irn_mode(n)));
/* skip all Sel nodes */
while (is_Sel(n)) {
n = get_Sel_ptr(n);
}
while (1) {
if (is_Proj(n)) { n = get_Proj_pred(n); continue; }
break;
}
if (is_SymConst_addr_ent(n)) {
/* global references are never NULL */
return 1;
} else if (n == get_irg_frame(get_irn_irg(n))) {
/* local references are never NULL */
return 1;
} else if (is_Alloc(n)) {
/* alloc never returns NULL (it throws an exception instead) */
return 1;
} else {
/* check for more Confirms */
for (; is_Confirm(n); n = get_Confirm_value(n)) {
if (get_Confirm_relation(n) == ir_relation_less_greater) {
ir_node *bound = get_Confirm_bound(n);
ir_tarval *tv = value_of(bound);
if (tarval_is_null(tv)) {
*confirm = n;
return 1;
}
}
}
}
return 0;
}
static ir_type *get_Sel_or_SymConst_type(ir_node *sos)
{
assert (is_Sel(sos) || is_SymConst_addr_ent(sos));
ir_entity *entity = get_irn_entity_attr(sos);
ir_type *type = get_entity_type(entity);
if (is_Method_type(type)) {
size_t n_ress = get_method_n_ress(type);
if (n_ress == 0)
return NULL;
assert (n_ress == 1);
type = get_method_res_type(type, 0);
}
if (is_Pointer_type(type))
type = get_pointer_points_to_type(type);
if (is_Class_type(type))
return type;
return NULL;
}
static void infer_typeinfo_walker(ir_node *irn, void *env)
{
bool *changed = (bool*) env;
// A node's type needs only to be calculated once.
if (get_irn_typeinfo_type(irn) != initial_type)
return;
if (is_Alloc(irn)) {
// this one is easy, we know the exact dynamic type.
ir_type *type = get_Alloc_type(irn);
if (! is_Class_type(type))
return;
set_irn_typeinfo_type(irn, type);
*changed = true;
}
else if (is_Sel(irn) || is_SymConst_addr_ent(irn)) {
// the type we determine here is the one of the entity we select or reference.
// the transform_Sel method below will use the type incoming on the Sel_ptr input.
ir_type *type = get_Sel_or_SymConst_type(irn);
if (! type)
return;
ir_type *one_alive = get_alive_subclass(type);
if (! one_alive)
return;
set_irn_typeinfo_type(irn, one_alive);
*changed = true;
}
else if (is_Call(irn)) {
// the dynamic type of the call result is the return type of the called entity.
ir_node *call_pred = get_Call_ptr(irn);
ir_type *pred_type = get_irn_typeinfo_type(call_pred);
if (pred_type == initial_type)
return;
set_irn_typeinfo_type(irn, pred_type);
*changed = true;
}
else if (is_Load(irn)) {
// the dynamic type of the Load result is the type of the loaded entity.
ir_node *load_pred = get_Load_ptr(irn);
if (! is_Sel(load_pred) && !is_SymConst_addr_ent(load_pred))
return;
ir_type *pred_type = get_irn_typeinfo_type(load_pred);
if (pred_type == initial_type)
return;
set_irn_typeinfo_type(irn, pred_type);
*changed = true;
}
else if (is_Proj(irn)) {
// Types have to be propagated through Proj nodes (XXX: and also through Cast and Confirm
ir_mode *pmode = get_irn_mode(irn);
if (pmode != mode_P)
return;
ir_node *proj_pred = get_Proj_pred(irn);
if (is_Proj(proj_pred) && get_irn_mode(proj_pred) == mode_T && get_Proj_proj(proj_pred) == pn_Call_T_result && is_Call(get_Proj_pred(proj_pred)))
proj_pred = get_Proj_pred(proj_pred); // skip the result tuple
ir_type *pred_type = get_irn_typeinfo_type(proj_pred);
if (pred_type == initial_type)
return;
set_irn_typeinfo_type(irn, pred_type);
*changed = true;
}
else if (is_Phi(irn)) {
// Phi nodes are a special case because the incoming type information must be merged
// A Phi node's type is unknown until all inputs are known to be the same dynamic type.
ir_mode *pmode = get_irn_mode(irn);
if (pmode != mode_P)
return;
int phi_preds = get_Phi_n_preds(irn);
ir_type *last = NULL;
for (int p = 0; p < phi_preds; p++) {
ir_node *pred = get_Phi_pred(irn, p);
ir_type *pred_type = get_irn_typeinfo_type(pred);
if (pred_type == initial_type)
return;
if (p && last != pred_type)
return;
last = pred_type;
}
set_irn_typeinfo_type(irn, last);
}
}
/*
* Check, if the value of a node is != 0.
*
* This is a often needed case, so we handle here Confirm
* nodes too.
*/
int value_not_zero(const ir_node *n, const ir_node **confirm)
{
#define RET_ON(x) if (x) { *confirm = n; return 1; } break
ir_tarval *tv;
ir_mode *mode = get_irn_mode(n);
ir_relation relation;
*confirm = NULL;
/* there might be several Confirms one after other that form an interval */
for (;;) {
if (is_Minus(n)) {
/* we can safely skip Minus when checking for != 0 */
n = get_Minus_op(n);
continue;
}
if (! is_Confirm(n))
break;
/*
* Note: A Confirm is never after a Const. So,
* we simply can check the bound for being a Const
* without the fear that is might be hidden by a further Confirm.
*/
tv = value_of(get_Confirm_bound(n));
if (tv == tarval_bad) {
n = get_Confirm_value(n);
continue;
}
relation = tarval_cmp(tv, get_mode_null(mode));
/*
* Beware: C might by a NaN. It is not clear, what we should do
* than. Of course a NaN is != 0, but we might use this function
* to remove up Exceptions, and NaN's might generate Exception.
* So, we do NOT handle NaNs here for safety.
*
* Note that only the C != 0 case need additional checking.
*/
switch (get_Confirm_relation(n)) {
case ir_relation_equal: /* n == C /\ C != 0 ==> n != 0 */
RET_ON(relation != ir_relation_equal && relation != ir_relation_unordered);
case ir_relation_less_greater: /* n != C /\ C == 0 ==> n != 0 */
RET_ON(relation == ir_relation_equal);
case ir_relation_less: /* n < C /\ C <= 0 ==> n != 0 */
RET_ON(relation == ir_relation_less || relation == ir_relation_equal);
case ir_relation_less_equal: /* n <= C /\ C < 0 ==> n != 0 */
RET_ON(relation == ir_relation_less);
case ir_relation_greater_equal: /* n >= C /\ C > 0 ==> n != 0 */
RET_ON(relation == ir_relation_greater);
case ir_relation_greater: /* n > C /\ C >= 0 ==> n != 0 */
RET_ON(relation == ir_relation_greater || relation == ir_relation_equal);
default:
break;
}
n = get_Confirm_value(n);
}
/* global entities are never NULL */
if (is_SymConst_addr_ent(n))
return true;
tv = value_of(n);
if (tv == tarval_bad)
return false;
relation = tarval_cmp(tv, get_mode_null(mode));
/* again, need check for NaN */
return (relation != ir_relation_equal) && (relation != ir_relation_unordered);
#undef RET_ON
}
/**
* Walk recursive the successors of a graph argument
* with mode reference and mark if it will be read,
* written or stored.
*
* @param arg The graph argument with mode reference,
* that must be checked.
*/
static ptr_access_kind analyze_arg(ir_node *arg, ptr_access_kind bits)
{
/* We must visit a node once to avoid endless recursion.*/
mark_irn_visited(arg);
for (int i = get_irn_n_outs(arg); i-- > 0; ) {
ir_node *succ = get_irn_out(arg, i);
if (irn_visited(succ))
continue;
/* We should not walk over the memory edge.*/
if (get_irn_mode(succ) == mode_M)
continue;
/* If we reach with the recursion a Call node and our reference
isn't the address of this Call we accept that the reference will
be read and written if the graph of the method represented by
"Call" isn't computed else we analyze that graph. If our
reference is the address of this
Call node that mean the reference will be read.*/
switch (get_irn_opcode(succ)) {
case iro_Call: {
ir_node *ptr = get_Call_ptr(succ);
if (ptr == arg) {
/* Hmm: not sure what this is, most likely a read */
bits |= ptr_access_read;
} else {
ir_entity *meth_ent;
if (is_SymConst_addr_ent(ptr)) {
meth_ent = get_SymConst_entity(ptr);
for (int p = get_Call_n_params(succ); p-- > 0; ) {
if (get_Call_param(succ, p) == arg) {
/* an arg can be used more than once ! */
bits |= get_method_param_access(meth_ent, p);
}
}
} else if (is_Sel(ptr) && get_irp_callee_info_state() == irg_callee_info_consistent) {
/* is be a polymorphic call but callee information is available */
size_t n_params = get_Call_n_params(succ);
/* simply look into ALL possible callees */
for (int c = get_Call_n_callees(succ); c-- > 0; ) {
meth_ent = get_Call_callee(succ, c);
/* unknown_entity is used to signal that we don't know what is called */
if (is_unknown_entity(meth_ent)) {
bits |= ptr_access_all;
break;
}
for (size_t p = n_params; p-- > 0; ) {
if (get_Call_param(succ, p) == arg) {
/* an arg can be used more than once ! */
bits |= get_method_param_access(meth_ent, p);
}
}
}
} else /* can do anything */
bits |= ptr_access_all;
}
/* search stops here anyway */
continue;
}
case iro_Store:
/* We have reached a Store node => the reference is written or stored. */
if (get_Store_ptr(succ) == arg) {
/* written to */
bits |= ptr_access_write;
} else {
/* stored itself */
bits |= ptr_access_store;
}
/* search stops here anyway */
continue;
case iro_Load:
/* We have reached a Load node => the reference is read. */
bits |= ptr_access_read;
/* search stops here anyway */
continue;
case iro_Conv:
/* our address is casted into something unknown. Break our search. */
bits = ptr_access_all;
break;
default:
break;
}
/* If we know that, the argument will be read, write and stored, we
can break the recursion.*/
if (bits == ptr_access_all) {
bits = ptr_access_all;
break;
}
/*
* A calculation that do not lead to a reference mode ends our search.
* This is dangerous: It would allow to cast into integer and that cast back ...
* so, when we detect a Conv we go mad, see the Conv case above.
*/
if (!mode_is_reference(get_irn_mode(succ)))
continue;
/* follow further the address calculation */
bits = analyze_arg(succ, bits);
}
set_irn_link(arg, NULL);
return bits;
}
