Allow Turbofan optimization of Ignition generators

src/compiler.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler.h"
 
 #include <algorithm>
 
 #include "src/ast/ast-numbering.h"
 #include "src/ast/prettyprinter.h"
@@ skipping 717 matching lines @@
   ParseInfo* parse_info = info->parse_info();
 
   info->SetOptimizingForOsr(osr_ast_id);
 
   // Do not use Crankshaft/TurboFan if we need to be able to set break points.
   if (info->shared_info()->HasDebugInfo()) {
     info->AbortOptimization(kFunctionBeingDebugged);
     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>();
   }
 
   // Limit the number of times we try to optimize functions.
   const int kMaxOptCount =
       FLAG_deopt_every_n_times == 0 ? FLAG_max_opt_count : 1000;
   if (info->shared_info()->opt_count() > kMaxOptCount) {
     info->AbortOptimization(kOptimizedTooManyTimes);
     return MaybeHandle<Code>();
@@ skipping 992 matching lines @@
     MaybeHandle<Code> code;
     if (cached.code != nullptr) code = handle(cached.code);
     Handle<Context> native_context(function->context()->native_context());
     SharedFunctionInfo::AddToOptimizedCodeMap(shared, native_context, code,
                                               literals, BailoutId::None());
   }
 }
 
 }  // namespace internal
 }  // namespace v8