Delete CPS IR

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

-library dart2js.cps_ir_integrity;
-
-import '../tracer.dart' as tracer;
-import 'cps_ir_nodes.dart';
-import 'cps_ir_nodes_sexpr.dart';
-
-/// Dump S-expressions on error if the tracer is enabled.
-///
-/// Technically this has nothing to do with the tracer, but if you want one
-/// enabled, you typically want the other as well, so we use the same flag.
-const bool ENABLE_DUMP = tracer.TRACE_FILTER_PATTERN != null;
-
-enum ScopeType { InScope, InDefinition, NotInScope }
-
-/// Performs integrity checks on the CPS IR.
-///
-/// To be run for debugging purposes, not for use in production.
-///
-/// The following integrity checks are performed:
-///
-/// - References are in scope of their definitions.
-/// - Recursive Continuations and InvokeContinuations are marked as recursive.
-/// - InvokeContinuations have the same arity as their target.
-/// - Reference chains are valid doubly-linked lists.
-/// - Reference chains contain exactly the references that are in the IR.
-/// - Each definition object occurs only once in the IR (no redeclaring).
-/// - Each reference object occurs only once in the IR (no sharing).
-///
-class CheckCpsIntegrity extends TrampolineRecursiveVisitor {
-  FunctionDefinition topLevelNode;
-  final Map<Definition, ScopeType> inScope = <Definition, ScopeType>{};
-  final List<Definition> definitions = [];
-  String previousPass;
-
-  void handleDeclaration(Definition def) {
-    definitions.add(def);
-    // Check the reference chain for cycles broken links.
-    Reference anchor = null;
-    int i = 0;
-    for (Reference ref = def.firstRef; ref != null; ref = ref.next) {
-      if (ref.definition != def) {
-        error(
-            'Reference to ${ref.definition} found in '
-            'reference chain for $def',
-            def);
-      }
-      if (ref == anchor) {
-        error('Cyclic reference chain for $def', def);
-      }
-      if (i & ++i == 0) {
-        // Move the anchor every 2^Nth step.
-        anchor = ref;
-      }
-    }
-  }
-
-  void enterScope(Iterable<Definition> definitions) {
-    for (Definition def in definitions) {
-      inScope[def] = ScopeType.InScope;
-    }
-    pushAction(() {
-      for (Definition def in definitions) {
-        inScope[def] = ScopeType.NotInScope;
-      }
-    });
-  }
-
-  void enterContinuation(Continuation cont) {
-    inScope[cont] = ScopeType.InDefinition;
-    pushAction(() {
-      inScope[cont] = ScopeType.NotInScope;
-    });
-  }
-
-  void check(FunctionDefinition node, String previousPass) {
-    // [check] will be called multiple times per instance to avoid reallocating
-    // the large [inScope] map. Reset the other fields.
-    this.topLevelNode = node;
-    this.previousPass = previousPass;
-    this.definitions.clear();
-    ParentChecker.checkParents(node, this);
-    visit(node);
-    // Check for broken reference chains. We check this last, so out-of-scope
-    // references are not classified as a broken reference chain.
-    definitions.forEach(checkReferenceChain);
-  }
-
-  @override
-  Expression traverseLetCont(LetCont node) {
-    node.continuations.forEach(handleDeclaration);
-    node.continuations.forEach(push);
-
-    // Put all continuations in scope when visiting the body.
-    enterScope(node.continuations);
-
-    return node.body;
-  }
-
-  @override
-  Expression traverseLetPrim(LetPrim node) {
-    handleDeclaration(node.primitive);
-
-    // Process references in the primitive.
-    visit(node.primitive);
-
-    // Put the primitive in scope when visiting the body.
-    enterScope([node.primitive]);
-
-    return node.body;
-  }
-
-  @override
-  Expression traverseLetMutable(LetMutable node) {
-    handleDeclaration(node.variable);
-    processReference(node.valueRef);
-
-    // Put the primitive in scope when visiting the body.
-    enterScope([node.variable]);
-
-    return node.body;
-  }
-
-  @override
-  Expression traverseContinuation(Continuation cont) {
-    if (cont.isReturnContinuation) {
-      error('Non-return continuation missing body', cont);
-    }
-    cont.parameters.forEach(handleDeclaration);
-    enterScope(cont.parameters);
-    // Put every continuation in scope at its own body. The isRecursive
-    // flag is checked explicitly using [insideContinuations].
-    enterScope([cont]);
-    enterContinuation(cont);
-    return cont.body;
-  }
-
-  @override
-  visitFunctionDefinition(FunctionDefinition node) {
-    if (node.interceptorParameter != null) {
-      handleDeclaration(node.interceptorParameter);
-      enterScope([node.interceptorParameter]);
-    }
-    if (node.receiverParameter != null) {
-      handleDeclaration(node.receiverParameter);
-      enterScope([node.receiverParameter]);
-    }
-    node.parameters.forEach(handleDeclaration);
-    enterScope(node.parameters);
-    handleDeclaration(node.returnContinuation);
-    enterScope([node.returnContinuation]);
-    if (!node.returnContinuation.isReturnContinuation) {
-      error('Return continuation with a body', node);
-    }
-    visit(node.body);
-  }
-
-  @override
-  processReference(Reference ref) {
-    Definition def = ref.definition;
-    if (inScope[def] == ScopeType.NotInScope) {
-      error('Referenced out of scope: $def', ref);
-    }
-    if (ref.previous == ref) {
-      error('Shared Reference object to $def', ref);
-    }
-    if (ref.previous == null && def.firstRef != ref ||
-        ref.previous != null && ref.previous.next != ref) {
-      error('Broken .previous link in reference to $def', def);
-    }
-    ref.previous = ref; // Mark reference as "seen". We will repair it later.
-  }
-
-  @override
-  processInvokeContinuation(InvokeContinuation node) {
-    Continuation target = node.continuation;
-    if (node.isRecursive && inScope[target] == ScopeType.InScope) {
-      error('Non-recursive InvokeContinuation marked as recursive', node);
-    }
-    if (!node.isRecursive && inScope[target] == ScopeType.InDefinition) {
-      error('Recursive InvokeContinuation marked as non-recursive', node);
-    }
-    if (node.isRecursive && !target.isRecursive) {
-      error('Recursive Continuation was not marked as recursive', node);
-    }
-    if (node.argumentRefs.length != target.parameters.length) {
-      error('Arity mismatch in InvokeContinuation', node);
-    }
-  }
-
-  @override
-  processInvokeMethod(InvokeMethod node) {
-    if (node.callingConvention == CallingConvention.Intercepted) {
-      if (node.interceptorRef == null) {
-        error('No interceptor on intercepted call', node);
-      }
-    } else {
-      if (node.interceptorRef != null) {
-        error('Interceptor on call with ${node.callingConvention}', node);
-      }
-    }
-  }
-
-  void checkReferenceChain(Definition def) {
-    Reference previous = null;
-    for (Reference ref = def.firstRef; ref != null; ref = ref.next) {
-      if (ref.previous != ref) {
-        // Reference was not seen during IR traversal, so it is orphaned.
-        error('Orphaned reference in reference chain for $def', def);
-      }
-      // Repair the .previous link that was used for marking.
-      ref.previous = previous;
-      previous = ref;
-    }
-  }
-
-  error(String message, node) {
-    String sexpr;
-    if (ENABLE_DUMP) {
-      try {
-        Decorator decorator = (n, String s) => n == node ? '**$s**' : s;
-        sexpr = new SExpressionStringifier(decorator).visit(topLevelNode);
-        sexpr = 'SExpr dump (offending node marked with **):\n\n$sexpr';
-      } catch (e) {
-        sexpr = '(Exception thrown by SExpressionStringifier: $e)';
-      }
-    } else {
-      sexpr = '(Set DUMP_IR flag to enable SExpr dump)';
-    }
-    throw 'CPS integrity violation\n'
-        'After \'$previousPass\' on ${topLevelNode.element}\n'
-        '$message\n\n'
-        '$sexpr\n';
-  }
-}
-
-/// Traverses the CPS term and checks that node.parent is correctly set
-/// for each visited node.
-class ParentChecker extends DeepRecursiveVisitor {
-  static void checkParents(Node node, CheckCpsIntegrity main) {
-    ParentChecker visitor = new ParentChecker._make(main);
-    visitor._worklist.add(node);
-    visitor.trampoline();
-  }
-
-  ParentChecker._make(this.main);
-
-  Node _parent;
-  final List<Node> _worklist = <Node>[];
-  final CheckCpsIntegrity main;
-
-  void trampoline() {
-    while (_worklist.isNotEmpty) {
-      _parent = _worklist.removeLast();
-      _parent.accept(this);
-    }
-  }
-
-  error(String message, node) => main.error(message, node);
-
-  @override
-  visit(Node node) {
-    _worklist.add(node);
-    if (node.parent != _parent) {
-      error('Parent pointer on $node is ${node.parent} but should be $_parent',
-          node);
-    }
-  }
-
-  @override
-  processReference(Reference node) {
-    if (node.parent != _parent) {
-      error('Parent pointer on $node is ${node.parent} but should be $_parent',
-          node);
-    }
-  }
-}