[turbofan] reenable escape analysis to further investigate crashes

src/compiler/escape-analysis.cc

 // Copyright 2015 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/escape-analysis.h"
 
 #include <limits>
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
@@ skipping 423 matching lines @@
 
 }  // namespace
 
 bool VirtualObject::MergeFields(size_t i, Node* at, MergeCache* cache,
                                 Graph* graph, CommonOperatorBuilder* common) {
   bool changed = false;
   int value_input_count = static_cast<int>(cache->fields().size());
   Node* rep = GetField(i);
   if (!rep || !IsCreatedPhi(i)) {
     Node* control = NodeProperties::GetControlInput(at);
+
+    // Check to debug canary.
+    CHECK_NOT_NULL(control);
+    CHECK(!control->IsDead());
+    for (Node* input : cache->fields()) {
+      CHECK_NOT_NULL(input);
+      CHECK(!input->IsDead());
+    }
+
     cache->fields().push_back(control);
     Node* phi = graph->NewNode(
         common->Phi(MachineRepresentation::kTagged, value_input_count),
         value_input_count + 1, &cache->fields().front());
     SetField(i, phi, true);
 #ifdef DEBUG
     if (FLAG_trace_turbo_escape) {
       PrintF("    Creating Phi #%d as merge of", phi->id());
       for (int i = 0; i < value_input_count; i++) {
         PrintF(" #%d (%s)", cache->fields()[i]->id(),
@@ skipping 1231 matching lines @@
     }
   }
   return false;
 }
 
 Graph* EscapeAnalysis::graph() const { return status_analysis_->graph(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8