void Canonicalizer::do_ArrayLength (ArrayLength* x) {
NewArray* array = x->array()->as_NewArray();
if (array != NULL && array->length() != NULL) {
Constant* length = array->length()->as_Constant();
if (length != NULL) {
// do not use the Constant itself, but create a new Constant
// with same value Otherwise a Constant is live over multiple
// blocks without being registered in a state array.
assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
set_constant(length->type()->as_IntConstant()->value());
}
} else {
LoadField* lf = x->array()->as_LoadField();
if (lf != NULL) {
ciField* field = lf->field();
if (field->is_constant() && field->is_static()) {
// final static field
ciObject* c = field->constant_value().as_object();
if (c->is_array()) {
ciArray* array = (ciArray*) c;
set_constant(array->length());
}
}
}
}
}
void Canonicalizer::do_ArrayLength (ArrayLength* x) {
NewArray* na;
Constant* ct;
LoadField* lf;
if ((na = x->array()->as_NewArray()) != NULL) {
// New arrays might have the known length.
// Do not use the Constant itself, but create a new Constant
// with same value Otherwise a Constant is live over multiple
// blocks without being registered in a state array.
Constant* length;
if (na->length() != NULL &&
(length = na->length()->as_Constant()) != NULL) {
assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
set_constant(length->type()->as_IntConstant()->value());
}
} else if ((ct = x->array()->as_Constant()) != NULL) {
// Constant arrays have constant lengths.
ArrayConstant* cnst = ct->type()->as_ArrayConstant();
if (cnst != NULL) {
set_constant(cnst->value()->length());
}
} else if ((lf = x->array()->as_LoadField()) != NULL) {
ciField* field = lf->field();
if (field->is_static_constant()) {
assert(PatchALot || ScavengeRootsInCode < 2, "Constant field loads are folded during parsing");
ciObject* c = field->constant_value().as_object();
if (!c->is_null_object()) {
set_constant(c->as_array()->length());
}
}
}
}
// perform constant and interval tests on index value
bool AccessIndexed::compute_needs_range_check() {
Constant* clength = length()->as_Constant();
Constant* cindex = index()->as_Constant();
if (clength && cindex) {
IntConstant* l = clength->type()->as_IntConstant();
IntConstant* i = cindex->type()->as_IntConstant();
if (l && i && i->value() < l->value() && i->value() >= 0) {
return false;
}
}
return true;
}
static bool match_index_and_scale(Instruction* instr,
Instruction** index,
int* log2_scale,
Instruction** instr_to_unpin) {
*instr_to_unpin = NULL;
// Skip conversion ops
Convert* convert = instr->as_Convert();
if (convert != NULL) {
instr = convert->value();
}
ShiftOp* shift = instr->as_ShiftOp();
if (shift != NULL) {
if (shift->is_pinned()) {
*instr_to_unpin = shift;
}
// Constant shift value?
Constant* con = shift->y()->as_Constant();
if (con == NULL) return false;
// Well-known type and value?
IntConstant* val = con->type()->as_IntConstant();
if (val == NULL) return false;
if (shift->x()->type() != intType) return false;
*index = shift->x();
int tmp_scale = val->value();
if (tmp_scale >= 0 && tmp_scale < 4) {
*log2_scale = tmp_scale;
return true;
} else {
return false;
}
}
ArithmeticOp* arith = instr->as_ArithmeticOp();
if (arith != NULL) {
if (arith->is_pinned()) {
*instr_to_unpin = arith;
}
// Check for integer multiply
if (arith->op() == Bytecodes::_imul) {
// See if either arg is a known constant
Constant* con = arith->x()->as_Constant();
if (con != NULL) {
*index = arith->y();
} else {
con = arith->y()->as_Constant();
if (con == NULL) return false;
*index = arith->x();
}
if ((*index)->type() != intType) return false;
// Well-known type and value?
IntConstant* val = con->type()->as_IntConstant();
if (val == NULL) return false;
switch (val->value()) {
case 1: *log2_scale = 0; return true;
case 2: *log2_scale = 1; return true;
case 4: *log2_scale = 2; return true;
case 8: *log2_scale = 3; return true;
default: return false;
}
}
}
// Unknown instruction sequence; don't touch it
return false;
}
