blob: 1406a58829e55089964079d6f78ddaf9c8749228 [file] [log] [blame]
library dart2js.cps_ir.finalize;
import 'cps_ir_nodes.dart';
import 'cps_fragment.dart';
import 'optimizers.dart' show Pass;
import '../js_backend/js_backend.dart' show JavaScriptBackend;
import '../js_backend/backend_helpers.dart';
/// A transformation pass that must run immediately before the tree IR builder.
///
/// This expands [BoundsCheck] nodes into more low-level operations.
class Finalize extends TrampolineRecursiveVisitor implements Pass {
String get passName => 'Finalize';
JavaScriptBackend backend;
BackendHelpers get helpers => backend.helpers;
Finalize(this.backend);
void rewrite(FunctionDefinition node) {
visit(node);
}
Expression traverseLetPrim(LetPrim node) {
CpsFragment cps = visit(node.primitive);
if (cps == null) return node.body;
cps.insertBelow(node);
Expression next = node.body;
node.remove();
return next;
}
bool areAdjacent(Primitive first, Primitive second) {
return first.parent == second.parent.parent;
}
CpsFragment visitBoundsCheck(BoundsCheck node) {
CpsFragment cps = new CpsFragment(node.sourceInformation);
if (node.hasNoChecks) {
node..replaceUsesWith(node.object.definition)..destroy();
return cps;
}
Continuation fail = cps.letCont();
if (node.hasLowerBoundCheck) {
cps.ifTruthy(cps.applyBuiltin(BuiltinOperator.NumLt,
[node.index.definition, cps.makeZero()]))
.invokeContinuation(fail);
}
if (node.hasUpperBoundCheck) {
Primitive length = node.length.definition;
if (length is GetLength &&
length.hasExactlyOneUse &&
areAdjacent(length, node)) {
// Rebind the GetLength here, so it does not get stuck outside the
// condition, blocked from propagating by the lower bounds check.
LetPrim lengthBinding = length.parent;
lengthBinding.remove();
cps.letPrim(length);
}
cps.ifTruthy(cps.applyBuiltin(BuiltinOperator.NumGe,
[node.index.definition, length]))
.invokeContinuation(fail);
}
if (node.hasEmptinessCheck) {
cps.ifTruthy(cps.applyBuiltin(BuiltinOperator.StrictEq,
[node.length.definition, cps.makeZero()]))
.invokeContinuation(fail);
}
cps.insideContinuation(fail).invokeStaticThrower(
helpers.throwIndexOutOfRangeException,
[node.object.definition, node.index.definition]);
node..replaceUsesWith(node.object.definition)..destroy();
return cps;
}
void visitGetStatic(GetStatic node) {
if (node.witness != null) {
node..witness.unlink()..witness = null;
}
}
}