[turbofan] Fix JSInliner to handle non-returning bodies.

src/compiler/js-inlining.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/js-inlining.h"
 
 #include "src/ast.h"
 #include "src/ast-numbering.h"
 #include "src/compiler.h"
 #include "src/compiler/all-nodes.h"
@@ skipping 171 matching lines @@
       case IrOpcode::kThrow:
         jsgraph_->graph()->end()->AppendInput(jsgraph_->zone(), input);
         jsgraph_->graph()->end()->set_op(
             jsgraph_->common()->End(jsgraph_->graph()->end()->InputCount()));
         break;
       default:
         UNREACHABLE();
         break;
     }
   }
-  DCHECK_NE(0u, values.size());
   DCHECK_EQ(values.size(), effects.size());
   DCHECK_EQ(values.size(), controls.size());
-  int const input_count = static_cast<int>(controls.size());
-  Node* control_output = jsgraph_->graph()->NewNode(
-      jsgraph_->common()->Merge(input_count), input_count, &controls.front());
-  values.push_back(control_output);
-  effects.push_back(control_output);
-  Node* value_output = jsgraph_->graph()->NewNode(
-      jsgraph_->common()->Phi(kMachAnyTagged, input_count),
-      static_cast<int>(values.size()), &values.front());
-  Node* effect_output = jsgraph_->graph()->NewNode(
-      jsgraph_->common()->EffectPhi(input_count),
-      static_cast<int>(effects.size()), &effects.front());
 
-  ReplaceWithValue(call, value_output, effect_output, control_output);
-
-  return Changed(value_output);
+  // Depending on whether the inlinee produces a value, we either replace value
+  // uses with said value or kill value uses if no value can be returned.
+  if (values.size() > 0) {
+    int const input_count = static_cast<int>(controls.size());
+    Node* control_output = jsgraph_->graph()->NewNode(
+        jsgraph_->common()->Merge(input_count), input_count, &controls.front());
+    values.push_back(control_output);
+    effects.push_back(control_output);
+    Node* value_output = jsgraph_->graph()->NewNode(
+        jsgraph_->common()->Phi(kMachAnyTagged, input_count),
+        static_cast<int>(values.size()), &values.front());
+    Node* effect_output = jsgraph_->graph()->NewNode(
+        jsgraph_->common()->EffectPhi(input_count),
+        static_cast<int>(effects.size()), &effects.front());
+    ReplaceWithValue(call, value_output, effect_output, control_output);
+    return Changed(value_output);
+  } else {
+    ReplaceWithValue(call, call, call, jsgraph_->Dead());

[Michael Starzinger, 2015/09/15 09:44:15]

Ideally this could be a helper method on AdvancedReducer::Editor named something
like "ReplaceWithUnreachable" or similar. But I cannot imagine any valid use of
said method outside the JSInliner, hence I would prefer to leave it as it is for
now. Would that be fine with you?

+    return Changed(call);
+  }
 }
 
 
 Node* JSInliner::CreateArgumentsAdaptorFrameState(
     JSCallFunctionAccessor* call, Handle<SharedFunctionInfo> shared_info,
     Zone* temp_zone) {
   const FrameStateFunctionInfo* state_info =
       jsgraph_->common()->CreateFrameStateFunctionInfo(
           FrameStateType::kArgumentsAdaptor,
           static_cast<int>(call->formal_arguments()) + 1, 0, shared_info,
@@ skipping 140 matching lines @@
 
   // Remember that we inlined this function.
   info_->AddInlinedFunction(info.shared_info());
 
   return InlineCall(node, context, frame_state, start, end);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8