[turbofan] Fixing ES6 tail calls in Turbofan.

src/compiler/instruction-selector.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/instruction-selector.h"
 
 #include <limits>
 
 #include "src/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
@@ skipping 560 matching lines @@
   }
   DCHECK_EQ(1u, buffer->instruction_args.size());
 
   // If the call needs a frame state, we insert the state information as
   // follows (n is the number of value inputs to the frame state):
   // arg 1               : deoptimization id.
   // arg 2 - arg (n + 1) : value inputs to the frame state.
   size_t frame_state_entries = 0;
   USE(frame_state_entries);  // frame_state_entries is only used for debug.
   if (buffer->frame_state_descriptor != nullptr) {
+    Node* frame_state =
+        call->InputAt(static_cast<int>(buffer->descriptor->InputCount()));
+
+    // If it was a syntactic tail call we need to drop the current frame and
+    // an arguments adaptor frame on top of it (if the latter is present).
+    if (buffer->descriptor->SupportsTailCalls()) {
+      frame_state = NodeProperties::GetFrameStateInput(frame_state, 0);
+      buffer->frame_state_descriptor =
+          buffer->frame_state_descriptor->outer_state();
+
+      if (buffer->frame_state_descriptor != nullptr &&
+          buffer->frame_state_descriptor->type() ==
+              FrameStateType::kArgumentsAdaptor) {
+        frame_state = NodeProperties::GetFrameStateInput(frame_state, 0);
+        buffer->frame_state_descriptor =
+            buffer->frame_state_descriptor->outer_state();
+      }
+    }
+
     InstructionSequence::StateId state_id =
         sequence()->AddFrameStateDescriptor(buffer->frame_state_descriptor);
     buffer->instruction_args.push_back(g.TempImmediate(state_id.ToInt()));
 
-    Node* frame_state =
-        call->InputAt(static_cast<int>(buffer->descriptor->InputCount()));
-
     StateObjectDeduplicator deduplicator(instruction_zone());
 
     frame_state_entries =
         1 + AddInputsToFrameStateDescriptor(
                 buffer->frame_state_descriptor, frame_state, &g, &deduplicator,
                 &buffer->instruction_args, FrameStateInputKind::kStackSlot,
                 instruction_zone());
 
     DCHECK_EQ(1 + frame_state_entries, buffer->instruction_args.size());
   }
@@ skipping 1051 matching lines @@
   return new (instruction_zone()) FrameStateDescriptor(
       instruction_zone(), state_info.type(), state_info.bailout_id(),
       state_info.state_combine(), parameters, locals, stack,
       state_info.shared_info(), outer_state);
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8