[interpreter] Implement OSR graph construction from bytecode.

src/compiler/pipeline.cc

 // Copyright 2014 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/pipeline.h"
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <memory>
 #include <sstream>
 
@@ skipping 1785 matching lines @@
   }
 
 #ifdef DEBUG
   data_->sequence()->ValidateEdgeSplitForm();
   data_->sequence()->ValidateDeferredBlockEntryPaths();
   data_->sequence()->ValidateDeferredBlockExitPaths();
 #endif
 
   data->InitializeRegisterAllocationData(config, descriptor);
   if (info()->is_osr()) {
+    AllowHandleDereference allow_deref;

[Jarin, 2016/07/26 14:46:36]

Out of curiosity, why is this needed?

[Michael Starzinger, 2016/07/26 14:58:51]

The constructor of {OsrHelper} dereferences the {SharedFunctionInfo} and the
{BytecodeArray} to compute frame size and parameter count. For the non-Ignition
case we were relying on scope analysis information, which is not available for
the {BytecodeGraphBuilder}. Note that OSR code is never compiled concurrently.

     OsrHelper osr_helper(info());
     osr_helper.SetupFrame(data->frame());
   }
 
   Run<MeetRegisterConstraintsPhase>();
   Run<ResolvePhisPhase>();
   Run<BuildLiveRangesPhase>();
   if (FLAG_trace_turbo_graph) {
     AllowHandleDereference allow_deref;
     OFStream os(stdout);
@@ skipping 50 matching lines @@
   data->DeleteRegisterAllocationZone();
 }
 
 CompilationInfo* PipelineImpl::info() const { return data_->info(); }
 
 Isolate* PipelineImpl::isolate() const { return info()->isolate(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8