Delete CPS IR

pkg/compiler/lib/src/cps_ir/loop_effects.dart

-library dart2js.cps_ir.loop_effects;
-
-import '../world.dart';
-import 'cps_ir_nodes.dart';
-import 'effects.dart';
-import 'loop_hierarchy.dart';
-
-/// Determines the side effects that may occur in each loop.
-class LoopSideEffects extends TrampolineRecursiveVisitor {
-  LoopHierarchy loopHierarchy;
-  final World world;
-  final Map<Continuation, List<Continuation>> exitContinuations = {};
-  final Map<Continuation, int> loopSideEffects = {};
-  Continuation currentLoopHeader;
-
-  LoopSideEffects(FunctionDefinition node, this.world, {this.loopHierarchy}) {
-    if (loopHierarchy == null) {
-      loopHierarchy = new LoopHierarchy(node);
-    }
-    visit(node);
-  }
-
-  /// Returns the accumulated effects and dependencies on all paths from the
-  /// loop entry to any recursive invocation of the loop.
-  int getSideEffectsInLoop(Continuation loop) {
-    return loopSideEffects[loop];
-  }
-
-  /// True if the length of an indexable object may change between the loop
-  /// entry and a recursive invocation of the loop.
-  bool changesIndexableLength(Continuation loop) {
-    return loopSideEffects[loop] & Effects.changesIndexableLength != 0;
-  }
-
-  @override
-  Expression traverseContinuation(Continuation cont) {
-    if (cont.isRecursive) {
-      loopSideEffects[cont] = Effects.none;
-      exitContinuations[cont] = <Continuation>[];
-      pushAction(() {
-        if (currentLoopHeader != null) {
-          loopSideEffects[currentLoopHeader] |= loopSideEffects[cont];
-        }
-        exitContinuations[cont].forEach(push);
-      });
-    }
-    Continuation oldLoopHeader = currentLoopHeader;
-    currentLoopHeader = loopHierarchy.getLoopHeader(cont);
-    pushAction(() {
-      currentLoopHeader = oldLoopHeader;
-    });
-    return cont.body;
-  }
-
-  @override
-  Expression traverseLetHandler(LetHandler node) {
-    enqueueContinuation(node.handler);
-    return node.body;
-  }
-
-  @override
-  Expression traverseLetCont(LetCont node) {
-    node.continuations.forEach(enqueueContinuation);
-    return node.body;
-  }
-
-  @override
-  Expression traverseLetPrim(LetPrim node) {
-    if (currentLoopHeader != null) {
-      loopSideEffects[currentLoopHeader] |= node.primitive.effects;
-    }
-    return node.body;
-  }
-
-  void enqueueContinuation(Continuation cont) {
-    Continuation loop = loopHierarchy.getEnclosingLoop(cont);
-    if (loop == currentLoopHeader) {
-      push(cont);
-    } else {
-      // Multiple loops can be exited at once.
-      // Register as an exit from the outermost loop being exited.
-      Continuation inner = currentLoopHeader;
-      Continuation outer = loopHierarchy.getEnclosingLoop(currentLoopHeader);
-      while (outer != loop) {
-        if (inner == null) {
-          // The shrinking reductions pass must run before any pass that relies
-          // on computing loop side effects.
-          world.compiler.reporter.internalError(
-              null,
-              'Unreachable continuations must be removed before computing '
-              'loop side effects.');
-        }
-        inner = outer;
-        outer = loopHierarchy.getEnclosingLoop(outer);
-      }
-      exitContinuations[inner].add(cont);
-    }
-  }
-}