Compile and run Hello World!

pkg/compiler/lib/src/kernel/kernel_backend_strategy.dart

Index: pkg/compiler/lib/src/kernel/kernel_backend_strategy.dart
diff --git a/pkg/compiler/lib/src/kernel/kernel_backend_strategy.dart b/pkg/compiler/lib/src/kernel/kernel_backend_strategy.dart
index 074b06c920a032de36efa22579eb0b1032e252c9..4eef86d51dc527b4ecfaa058f1db377ca40208ee 100644
--- a/pkg/compiler/lib/src/kernel/kernel_backend_strategy.dart
+++ b/pkg/compiler/lib/src/kernel/kernel_backend_strategy.dart
@@ -274,7 +274,8 @@ class KernelToLocalsMapImpl implements KernelToLocalsMap {
 
   @override
   JumpTarget getJumpTarget(ir.TreeNode node, {bool isContinueTarget: false}) {
-    throw new UnimplementedError('KernelToLocalsMapImpl.getJumpTarget');
+    // TODO(johnniwinther): Support jump targets.
+    return null;

[Emily Fortuna, 2017/06/15 17:54:34]

is this really better than throwing? I mean, it gets hello world compiling, but
it's hiding issues.

[Siggi Cherem (dart-lang), 2017/06/15 18:28:55]

one option here: throw in checked mode only?

[Johnni Winther, 2017/06/16 09:25:31]

This is the price for the machete approach. We need to clean up the leaves
afterwards. In this case: returning `null` means [node] has no jumps to it,
which is true for loops without continue.

We run unittests in checked mode, so no. 

[Siggi Cherem (dart-lang), 2017/06/16 16:35:24]

How about:

if (const bool.fromEnvironment("MACHETE_CLEANUP")) throw "support jump targets";

[Johnni Winther, 2017/06/19 10:57:38]

I'll consider it.

   }
 
   @override