Allow Turbofan optimization of Ignition generators

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 1fe623bbc9aefbd2765ba8b3657bef92d78ede1f..f3bc5f5f327aea0daddf3127618f3b7cb0b2e6a7 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -735,9 +735,8 @@ MaybeHandle<Code> GetOptimizedCode(Handle<JSFunction> function,
     return MaybeHandle<Code>();
   }
 
-  // Do not use Crankshaft/TurboFan on a generator function.
-  // TODO(neis): Eventually enable for Turbofan.
-  if (IsGeneratorFunction(info->shared_info()->kind())) {
+  // Do not use Crankshaft on a generator function.
+  if (IsGeneratorFunction(info->shared_info()->kind()) && !use_turbofan) {

[neis, 2016/05/10 10:03:22]

Does this make sense?

[rmcilroy, 2016/05/10 10:23:21]

I think you also need to check for the FLAG_turbo_from_bytecode, since this is
the only situation where bytecode-graph-builder will be used (otherwise we go
via FCG then via the ASTGraphBuilder to build the TF graph, which won't work for
generators).

[Michael Starzinger, 2016/05/10 10:37:11]

Rather than keeping this bailout here, we could move it into
HCompilationJob::CreateGraphImpl instead. This will make Crankshaft bailout of
the compilation. TurboFan will either bailout in the AstGraphBuilder or succeed
when going through the BytecodeGraphBuilder.

Note that the heuristic in AstNumberingVisitor remains untouched. So the bailout
we are talking about here are essentially just last-resort bailouts for
correctness. They can be arbitrary late in the pipeline.

[neis, 2016/05/10 11:32:06]

Done.

     info->AbortOptimization(kGenerator);
     return MaybeHandle<Code>();
   }