cps-ir: Support foreign code.

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

 // Copyright (c) 2013, 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.
 
 library dart2js.ir_builder_task;
 
 import '../closure.dart' as closurelib;
 import '../closure.dart' hide ClosureScope;
 import '../constants/expressions.dart';
 import '../dart_types.dart';
 import '../dart2jslib.dart';
 import '../elements/elements.dart';
 import '../elements/modelx.dart' show SynthesizedConstructorElementX,
     ConstructorBodyElementX, FunctionSignatureX;
 import '../io/source_information.dart';
 import '../js_backend/js_backend.dart' show JavaScriptBackend;
 import '../resolution/semantic_visitor.dart';
 import '../resolution/operators.dart' as op;
 import '../scanner/scannerlib.dart' show Token, isUserDefinableOperator;
 import '../tree/tree.dart' as ast;
 import '../universe/universe.dart' show SelectorKind, CallStructure;
 import 'cps_ir_nodes.dart' as ir;
 import 'cps_ir_builder.dart';
+import '../native/native.dart' show NativeBehavior;
+
+// TODO(karlklose): remove.
+import '../js/js.dart' as js show js, Template, Expression;
+import '../ssa/ssa.dart' show TypeMaskFactory;
+import '../types/types.dart' show TypeMask;
+import '../util/util.dart';
+
+import 'package:_internal/compiler/js_lib/shared/embedded_names.dart'
+    show JsBuiltin, JsGetName;
+import '../constants/values.dart';
 
 typedef void IrBuilderCallback(Element element, ir.FunctionDefinition irNode);
 
 /// This task provides the interface to build IR nodes from [ast.Node]s, which
 /// is used from the [CpsFunctionCompiler] to generate code.
 ///
 /// This class is mainly there to correctly measure how long building the IR
 /// takes.
 class IrBuilderTask extends CompilerTask {
   final SourceInformationFactory sourceInformationFactory;
@@ skipping 953 matching lines @@
         callStructure,
         translateDynamicArguments(arguments, callStructure));
   }
 
   @override
   ir.Primitive handleStaticFunctionInvoke(
       ast.Send node,
       MethodElement function,
       ast.NodeList arguments,
       CallStructure callStructure,
-      _) {
-    // TODO(karlklose): support foreign functions.
-    if (compiler.backend.isForeign(function)) {
-      return giveup(node, 'handleStaticFunctionInvoke: foreign: $function');
-    }
-    return irBuilder.buildStaticFunctionInvocation(function, callStructure,
-        translateStaticArguments(arguments, function, callStructure),
-        sourceInformation: sourceInformationBuilder.buildCall(node));
-  }
+      _);
 
   @override
   ir.Primitive handleStaticFunctionIncompatibleInvoke(
       ast.Send node,
       MethodElement function,
       ast.NodeList arguments,
       CallStructure callStructure, _) {
     return buildStaticNoSuchMethod(
         elements.getSelector(node),
         arguments.nodes.mapToList(visit));
@@ skipping 838 matching lines @@
     try {
       return action();
     } catch(e) {
       if (e == ABORT_IRNODE_BUILDER) {
         return null;
       }
       rethrow;
     }
   }
 
-  void internalError(ast.Node node, String message) {
+  internalError(ast.Node node, String message) {
     giveup(node, message);
   }
 
   @override
   visitNode(ast.Node node) {
     internalError(node, "Unhandled node");
   }
 
   dynamic giveup(ast.Node node, [String reason]) {
     bailoutMessage = '($node): $reason';
@@ skipping 172 matching lines @@
 
   /// Returns [true], if the analysis could not determine that the type
   /// arguments for the class [cls] are never used in the program.
   bool requiresRuntimeTypesFor(ClassElement cls) {
     return cls.typeVariables.isNotEmpty && _backend.classNeedsRti(cls);
   }
 
   FunctionElement get throwTypeErrorHelper => _backend.getThrowTypeError();
 
   ClassElement get nullClass => _compiler.nullClass;
+
+  TypeMask getTypeMaskForForeign(NativeBehavior behavior) {
+    return TypeMaskFactory.fromNativeBehavior(behavior, _compiler);
+  }
 }
 
 /// IR builder specific to the JavaScript backend, coupled to the [JsIrBuilder].
 class JsIrBuilderVisitor extends IrBuilderVisitor {
   /// Promote the type of [irBuilder] to [JsIrBuilder].
   JsIrBuilder get irBuilder => super.irBuilder;
 
   JavaScriptBackend get backend => compiler.backend;
 
   /// Result of closure conversion for the current body of code.
@@ skipping 731 matching lines @@
     ConstantExpression constant =
         backend.constants.getConstantForVariable(field);
     if (constant != null && !field.isAssignable) {
       return buildConstant(constant);
     } else if (backend.constants.lazyStatics.contains(field)) {
       return irBuilder.buildStaticFieldLazyGet(field, src);
     } else {
       return irBuilder.buildStaticFieldGet(field, src);
     }
   }
+
+  /// Build code to handle foreign code, that is, native JavaScript code, or
+  /// builtin values and operations of the backend.
+  ir.Primitive handleForeignSend(ast.Send node,
+                                 MethodElement function,
+                                 Link<ast.Node> argumentNodes,
+                                 CallStructure callStructure) {
+
+    void validateArgumentCount({int minimum, int exactly}) {
+      assert((minimum == null) != (exactly == null));
+      int count = 0;
+      if (exactly != null) {
+        minimum = exactly;
+      }
+      for (Link<ast.Node> arguments = argumentNodes;

[Kevin Millikin (Google), 2015/06/16 11:23:10]

I'd make argumentNodes a NodeList (to avoid exposing Link) and for-in to iterate
over it.

The implementation is a little confusing.  Maybe it's clearer to rename exactly
in the body:

int count = 0;
if (minimum == null) minimum = exactly;
int maximum = exactly;
for (ast.Node in argumentNodes) {
  ++count;
  if (maximum != null && count > maximum) internalError(...);
}
if (count < minimum) internalError(...);

[karlklose, 2015/06/18 09:38:14]

Done.

+           !arguments.isEmpty;
+           arguments = arguments.tail) {
+        count++;
+        if (exactly != null && count > exactly) {
+          internalError(arguments.head, 'Additional argument.');
+        }
+      }
+      if (minimum != null && count < minimum) {

[Kevin Millikin (Google), 2015/06/16 11:23:10]

minimum should always be non-null.

[karlklose, 2015/06/18 09:38:14]

Done.

+        internalError(node, 'Expected at least $minimum arguments.');
+      }
+    }
+
+    /// Call a helper method from the isolate library. The isolate library uses
+    /// its own isolate structure, that encapsulates dart2js's isolate.
+    ir.Primitive buildIsolateHelperInvocation(String helperName,
+                                              CallStructure callStructure,
+                                              Link<ast.Node> argumentNodes) {

[Kevin Millikin (Google), 2015/06/16 11:23:10]

argumentNodes is unused in this function.

[karlklose, 2015/06/18 09:38:14]

Done.

+      Element element = backend.isolateHelperLibrary.find(helperName);
+      if (element == null) {
+        compiler.internalError(node,
+            'Isolate library and compiler mismatch.');
+      }
+      List<ir.Primitive> arguments = translateStaticArguments(
+          node.argumentsNode, element, CallStructure.TWO_ARGS);

[Kevin Millikin (Google), 2015/06/16 11:23:10]

This uses the arguments NodeList off the Send.  It's hard to see if that's
always the same as the one that argumentNodes was derived from --- and if they
can be different it's not clear which one we should use here.

[karlklose, 2015/06/18 09:38:14]

Done.

+      return irBuilder.buildStaticFunctionInvocation(element,
+          CallStructure.TWO_ARGS, arguments,
+          sourceInformation: sourceInformationBuilder.buildCall(node));
+    }
+
+    /// Lookup the value of the enum described by [node].
+    getEnumValue(ast.Node node, EnumClassElement enumClass, List values) {
+      Element element = elements[node];
+      if (element is! FieldElement || element.enclosingClass != enumClass) {
+        internalError(node, 'expected a JsBuiltin enum value');
+      }
+
+      int index = enumClass.enumValues.indexOf(element);
+      return values[index];
+    }
+
+    /// Returns the String the node evaluates to, or throws an error if the
+    /// result is not a string constant.
+    String expectStringConstant(ast.Node node) {
+      ir.Primitive nameValue = visit(node);
+      if (nameValue is ir.Constant && nameValue.value.isString) {
+        StringConstantValue constantValue = nameValue.value;
+        return constantValue.primitiveValue.slowToString();
+      } else {
+        return internalError(node, 'expected a literal string');
+      }
+    }
+
+    NativeBehavior behavior =
+        compiler.enqueuer.resolution.nativeEnqueuer.getNativeBehaviorOf(node);
+    switch (function.name) {
+      case 'JS':
+        validateArgumentCount(minimum: 2);
+        // The first two arguments are the type and the foreign code template,
+        // which already have been analyzed by the resolver and can be retrieved
+        // using [NativeBehavior]. We can ignore these arguments in the backend.
+        List<ir.Primitive> arguments =
+            argumentNodes.skip(2).mapToList(visit, growable: false);
+        return irBuilder.buildForeignCode(behavior.codeTemplate, arguments,
+            behavior);
+
+      case 'DART_CLOSURE_TO_JS':
+        // TODO(ahe): This should probably take care to wrap the closure in
+        // another closure that saves the current isolate.
+      case 'RAW_DART_FUNCTION_REF':
+        validateArgumentCount(exactly: 1);
+
+        ast.Node argument = node.arguments.single;
+        FunctionElement closure = elements[argument].implementation;
+        if (!Elements.isStaticOrTopLevelFunction(closure)) {
+          internalError(argument,
+              'only static or toplevel function supported');
+        }
+        if (closure.functionSignature.hasOptionalParameters) {
+          internalError(argument,
+              'closures with optional parameters not supported');
+        }
+        return irBuilder.buildForeignCode(
+            js.js.expressionTemplateYielding(
+                        backend.emitter.staticFunctionAccess(function)),
+            <ir.Primitive>[],
+            NativeBehavior.PURE,
+            dependency: closure);
+
+      case 'JS_BUILTIN':
+        // The first argument is a description of the type and effect of the
+        // builtin, which has already been analyzed in the frontend.  The second
+        // argument must be a [JsBuiltin] value.  All other arguments are
+        // values used by the JavaScript template that is associated with the
+        // builtin.
+        validateArgumentCount(minimum: 2);
+
+        ast.Node builtin = argumentNodes.tail.head;
+        JsBuiltin value = getEnumValue(argumentNodes.tail.head,
+            backend.jsBuiltinEnum, JsBuiltin.values);
+        js.Template template = backend.emitter.builtinTemplateFor(value);
+        List<ir.Primitive> arguments =
+            argumentNodes.skip(2).mapToList(visit, growable: false);
+        return irBuilder.buildForeignCode(template, arguments, behavior);
+
+      case 'JS_EMBEDDED_GLOBAL':
+        validateArgumentCount(exactly: 2);
+
+        String name = expectStringConstant(argumentNodes.tail.head);
+        js.Expression access =
+            backend.emitter.generateEmbeddedGlobalAccess(name);
+        js.Template template = js.js.expressionTemplateYielding(access);
+        return irBuilder.buildForeignCode(template, <ir.Primitive>[], behavior);
+
+      case 'JS_INTERCEPTOR_CONSTANT':
+        validateArgumentCount(exactly: 1);
+
+        ast.Node argument = argumentNodes.head;
+        ir.Primitive argumentValue = visit(argument);
+        if (argumentValue is ir.Constant && argumentValue.value.isType) {
+          TypeConstantValue constant = argumentValue.value;
+          ConstantValue interceptorValue =
+              new InterceptorConstantValue(constant.representedType);
+          return irBuilder.buildConstant(argumentValue.expression,
+              interceptorValue);
+        } else {
+          internalError(argument, 'expected Type as argument');
+        }
+        break;
+
+      case 'JS_EFFECT':
+        return irBuilder.buildNullConstant();
+
+      case 'JS_GET_NAME':
+        validateArgumentCount(exactly: 1);
+
+        ast.Node argument = argumentNodes.head;
+        JsGetName id = getEnumValue(argument, backend.jsGetNameEnum,
+            JsGetName.values);
+        String name = backend.namer.getNameForJsGetName(argument, id);
+        return irBuilder.buildStringConstant(name);
+
+      case 'JS_GET_FLAG':
+        validateArgumentCount(exactly: 1);
+
+        String name = expectStringConstant(argumentNodes.first);
+        bool value = false;
+        switch (name) {
+          case 'MUST_RETAIN_METADATA':
+            value = backend.mustRetainMetadata;
+            break;
+          case 'USE_CONTENT_SECURITY_POLICY':
+            value = compiler.useContentSecurityPolicy;
+            break;
+          default:
+            internalError(node, 'Unknown internal flag "$name".');
+        }
+        return irBuilder.buildBooleanConstant(value);
+
+      case 'JS_STRING_CONCAT':
+        validateArgumentCount(exactly: 2);
+        List<ir.Primitive> arguments = argumentNodes.mapToList(visit);
+        return irBuilder.buildStringConcatenation(arguments);
+
+      case 'JS_CURRENT_ISOLATE_CONTEXT':
+        validateArgumentCount(exactly: 0);
+
+        if (!compiler.hasIsolateSupport) {
+          // If the isolate library is not used, we just generate code
+          // to fetch the current isolate.
+          String name = backend.namer.currentIsolate;
+          return irBuilder.buildForeignCode(js.js.parseForeignJS(name),
+              const <ir.Primitive>[], NativeBehavior.PURE);
+        } else {
+          return buildIsolateHelperInvocation('_currentIsolate',
+              CallStructure.NO_ARGS, argumentNodes);
+        }
+        break;
+
+      case 'JS_CALL_IN_ISOLATE':
+        validateArgumentCount(exactly: 2);
+
+        if (!compiler.hasIsolateSupport) {
+          ir.Primitive closure = visit(argumentNodes.tail.head);
+          return irBuilder.buildCallInvocation(closure, CallStructure.NO_ARGS,
+              const <ir.Primitive>[]);
+        } else {
+          return buildIsolateHelperInvocation('_callInIsolate',
+              CallStructure.TWO_ARGS, argumentNodes);
+        }
+        break;
+
+      default:
+        giveup(node, 'unplemented native construct: ${function.name}');
+        break;
+    }
+  }
+
+  @override
+  ir.Primitive handleStaticFunctionInvoke(ast.Send node,
+                                          MethodElement function,
+                                          ast.NodeList argumentList,
+                                          CallStructure callStructure,
+                                          _) {
+    if (compiler.backend.isForeign(function)) {
+      return handleForeignSend(node, function, argumentList.nodes,

[Kevin Millikin (Google), 2015/06/16 11:23:10]

"Send" seems weird here.  handleForeignCode?

[karlklose, 2015/06/18 09:38:14]

Done.

+          callStructure);
+    } else {
+      return irBuilder.buildStaticFunctionInvocation(function, callStructure,
+          translateStaticArguments(argumentList, function, callStructure),
+          sourceInformation: sourceInformationBuilder.buildCall(node));
+    }
+  }
 }
 
 /// Perform simple post-processing on the initial CPS-translated root term.
 ///
 /// This pass performs backend-independent post-processing on the translated
 /// term.  It is implemented separately from the optimization passes because
 /// it is required for correctness of the implementation.
 ///
 /// It performs the following translations:
 ///   - Replace [ir.LetPrim] binding a [ir.NonTailThrow] with a [ir.Throw]
@@ skipping 39 matching lines @@
   }
 
   processSetStatic(ir.SetStatic node) {
     node.body = replacementFor(node.body);
   }
 
   processContinuation(ir.Continuation node) {
     node.body = replacementFor(node.body);
   }
 }