Implement dynamic function checks.

dart/sdk/lib/_internal/compiler/implementation/ssa/builder.dart

Index: dart/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
diff --git a/dart/sdk/lib/_internal/compiler/implementation/ssa/builder.dart b/dart/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
index a0df3633e7c96c59ff7c62d9097470995719c6a2..4bbbd968398778ced44f4470657381d22c3cfe17 100644
--- a/dart/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
+++ b/dart/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
@@ -1885,6 +1885,19 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
       return new HTypeConversion.withTypeRepresentation(type, kind, subtype,
           original, typeVariable);
     } else if (type.kind == TypeKind.FUNCTION) {
+      // HERE
+      String name = kind == HTypeConversion.CAST_TYPE_CHECK
+          ? '_asCheck' : '_assertCheck';
+
+      List arguments = [buildFunctionType(type), original];
+      pushInvokeDynamic(
+          null,
+          new Selector.call(name, compiler.jsHelperLibrary, 1),
+          arguments);
+
+      return new HTypeConversion(type, kind, original.instructionType, pop());
+/*
+
       if (backend.rti.isSimpleFunctionType(type)) {
         return original.convertType(compiler, type, kind);
       }
@@ -1906,6 +1919,7 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
       } else {
         return new HTypeConversion(type, kind, subtype, original);
       }
+*/
     } else {
       return original.convertType(compiler, type, kind);
     }
@@ -2014,7 +2028,9 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
   }
 
   HInstruction attachPosition(HInstruction target, Node node) {
-    target.sourcePosition = sourceFileLocationForBeginToken(node);
+    if (node != null) {
+      target.sourcePosition = sourceFileLocationForBeginToken(node);
+    }
     return target;
   }
 
@@ -2916,9 +2932,39 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
     return buildLiteralList(inputs);
   }
 
+  HInstruction buildFunctionType(FunctionType type) {
+    List<HInstruction> typeVariables = <HInstruction>[];

[Johnni Winther, 2013/10/30 12:02:19]

Make [typeVariables] a Map<TypeVariableElement, HInstruction> instead. This way
you can reuse the instructions and handle typedefs.

[ahe, 2013/11/29 13:10:17]

Just tried it, it doesn't work. I don't think you can use an instruction
multiple times (unless you do something special).

I found a different solution: generate type variables as needed. GVN should take
care of the rest.

+    bool hasDirectTypeVariables =
+        !currentElement.enclosingElement.isClosure() &&
+        currentElement.isInstanceMember();
+
+    type.forEachTypeVariable((TypeVariableType variable) {
+      if (hasDirectTypeVariables) {
+        HInstruction receiver = localsHandler.readThis();
+        push(new HReadTypeVariable(variable, receiver));
+      } else {
+        push(
+            new HReadTypeVariable.noReceiver(
+                variable, addTypeVariableReference(variable)));
+      }
+      typeVariables.add(pop());
+    });
+    push(new HFunctionType(typeVariables, type));
+    return pop();
+  }
+
   HInstruction buildIsNode(Node node, DartType type, HInstruction expression) {
     type = type.unalias(compiler);
     if (type.kind == TypeKind.FUNCTION) {
+      // HERE
+      List arguments = [buildFunctionType(type), expression];
+      pushInvokeDynamic(
+          node, new Selector.call('_isTest', compiler.jsHelperLibrary, 1),
+          arguments);
+
+      return new HIs.compound(type, expression, pop());
+
+/*
       if (backend.rti.isSimpleFunctionType(type)) {
         // TODO(johnniwinther): Avoid interceptor if unneeded.
         return new HIs.raw(type, expression, invokeInterceptor(expression));
@@ -2960,6 +3006,7 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
       pushInvokeStatic(node, checkFunctionSubtype, inputs, HType.BOOLEAN);
       HInstruction call = pop();
       return new HIs.compound(type, expression, call);
+*/
     } else if (type.kind == TypeKind.TYPE_VARIABLE) {
       HInstruction runtimeType = addTypeVariableReference(type);
       Element helper = backend.getCheckSubtypeOfRuntimeType();