Pulling the element model out of global type inference.

pkg/compiler/lib/src/inferrer/builder_kernel.dart

+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:kernel/ast.dart' as ir;
+
+import '../closure.dart';
+import '../compiler.dart';
+import '../elements/elements.dart';
+import '../elements/entities.dart';
+import '../kernel/kernel.dart';
+import '../ssa/kernel_ast_adapter.dart';
+import '../tree/tree.dart' as ast;
+import '../types/types.dart' show TypeMask;
+import '../universe/side_effects.dart' show SideEffects;
+import 'inferrer_engine.dart';
+import 'locals_handler.dart';
+import 'type_graph_nodes.dart';
+import 'type_system.dart';
+
+/// [KernelTypeGraphBuilder] constructs a type-inference graph for a particular
+/// element.
+///
+/// Calling [run] will start the work of visiting the body of the code to
+/// construct a set of inference-nodes that abstractly represent what the code
+/// is doing.
+class KernelTypeGraphBuilder extends ir.Visitor<TypeInformation> {
+  final Compiler compiler;
+  final AstElement originalElement;
+  // TODO(efortuna): Remove this.
+  final Element outermostElement;
+  final ir.Node analyzedNode;
+  final ResolvedAst resolvedAst;
+  final TypeSystem types;
+  LocalsHandler locals;
+  final InferrerEngine inferrer;
+  SideEffects sideEffects = new SideEffects.empty();
+  int loopLevel = 0;
+  bool get inLoop => loopLevel > 0;
+
+  final Set<Entity> capturedVariables = new Set<Entity>();
+
+  final KernelAstAdapter astAdapter;
+
+  KernelTypeGraphBuilder.internal(
+      this.originalElement,
+      this.resolvedAst,
+      this.outermostElement,
+      this.inferrer,
+      this.compiler,
+      this.locals,
+      this.astAdapter,
+      this.analyzedNode)
+      : this.types = inferrer.types {
+    if (locals != null) return;
+
+    ast.Node node;
+    if (resolvedAst.kind == ResolvedAstKind.PARSED) {
+      node = resolvedAst.node;
+    }
+    FieldInitializationScope fieldScope = (analyzedNode is ir.Constructor)
+        ? new FieldInitializationScope(types)
+        : null;
+    locals =
+        new LocalsHandler(inferrer, types, compiler.options, node, fieldScope);
+  }
+
+  factory KernelTypeGraphBuilder(Element element, ResolvedAst resolvedAst,
+      Compiler compiler, InferrerEngine inferrer,
+      [LocalsHandler handler]) {
+    var adapter = _createKernelAdapter(compiler, resolvedAst);
+    var node = adapter.getInitialKernelNode(element);
+    return new KernelTypeGraphBuilder.internal(
+        element,
+        resolvedAst,
+        element.outermostEnclosingMemberOrTopLevel.implementation,
+        inferrer,
+        compiler,
+        handler,
+        adapter,
+        node);
+  }
+
+  static KernelAstAdapter _createKernelAdapter(
+      Compiler compiler, ResolvedAst resolvedAst) {
+    Kernel kernel = compiler.backend.kernelTask.kernel;
+    return new KernelAstAdapter(kernel, compiler.backend, resolvedAst,
+        kernel.nodeToAst, kernel.nodeToElement);
+  }
+
+  TypeInformation run() {
+    ir.Expression initializer;
+    if (analyzedNode is ir.Field) {
+      ir.Field field = analyzedNode;
+      initializer = field.initializer;
+      if (initializer == null || initializer is ir.NullLiteral) {
+        // Eagerly bailout, because computing the closure data only
+        // works for functions and field assignments.
+        return types.nullType;
+      }
+    }
+
+    // Update the locals that are boxed in [locals]. These locals will
+    // be handled specially, in that we are computing their LUB at
+    // each update, and reading them yields the type that was found in a
+    // previous analysis of [outermostElement].
+    ClosureClassMap closureData =
+        compiler.closureToClassMapper.getClosureToClassMapping(resolvedAst);
+    closureData.forEachCapturedVariable((variable, field) {
+      locals.setCaptured(variable, field);
+    });
+    closureData.forEachBoxedVariable((variable, field) {
+      locals.setCapturedAndBoxed(variable, field);
+    });
+
+    if (analyzedNode is ir.Field) {
+      return initializer.accept(this);
+    }
+    return _processFunctionNode(analyzedNode);
+  }
+
+  TypeInformation _processFunctionNode(ir.FunctionNode funcNode) {
+    // TODO(efortuna): Implement.
+    return types.dynamicType;
+  }
+
+  @override
+  TypeInformation defaultExpression(ir.Expression expression) {
+    // TODO(efortuna): Remove when more is implemented.
+    return types.dynamicType;
+  }
+
+  @override
+  TypeInformation visitNullLiteral(ir.NullLiteral literal) {
+    return types.nullType;
+  }
+
+  @override
+  TypeInformation visitBlock(ir.Block block) {
+    for (ir.Statement statement in block.statements) {
+      statement.accept(this);
+      if (locals.aborts) break;
+    }
+    return null;
+  }
+
+  @override
+  TypeInformation visitListLiteral(ir.ListLiteral listLiteral) {
+    // We only set the type once. We don't need to re-visit the children
+    // when re-analyzing the node.
+    return inferrer.concreteKernelTypes.putIfAbsent(listLiteral, () {
+      TypeInformation elementType;
+      int length = 0;
+      for (ir.Expression element in listLiteral.expressions) {
+        TypeInformation type = element.accept(this);
+        elementType = elementType == null
+            ? types.allocatePhi(null, null, type)
+            : types.addPhiInput(null, elementType, type);
+        length++;
+      }
+      elementType = elementType == null
+          ? types.nonNullEmpty()
+          : types.simplifyPhi(null, null, elementType);
+      TypeInformation containerType =
+          listLiteral.isConst ? types.constListType : types.growableListType;
+      // TODO(efortuna): Change signature of allocateList and the rest of
+      // type_system to deal with Kernel elements.
+      return types.allocateList(containerType, astAdapter.getNode(listLiteral),
+          outermostElement, elementType, length);
+    });
+  }
+}