[es6] Tail calls support.

src/full-codegen/x64/full-codegen-x64.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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 2724 matching lines @@
 void FullCodeGenerator::EmitCall(Call* expr, ConvertReceiverMode mode) {
   // Load the arguments.
   ZoneList<Expression*>* args = expr->arguments();
   int arg_count = args->length();
   for (int i = 0; i < arg_count; i++) {
     VisitForStackValue(args->at(i));
   }
 
   PrepareForBailoutForId(expr->CallId(), NO_REGISTERS);
   SetCallPosition(expr);
-  Handle<Code> ic = CodeFactory::CallIC(isolate(), arg_count, mode).code();
+  TailCallMode tail_call_mode =
+      expr->is_tail() ? TailCallMode::kAllow : TailCallMode::kDisallow;
+  Handle<Code> ic =
+      CodeFactory::CallIC(isolate(), arg_count, mode, tail_call_mode).code();
   __ Move(rdx, SmiFromSlot(expr->CallFeedbackICSlot()));
   __ movp(rdi, Operand(rsp, (arg_count + 1) * kPointerSize));
   // Don't assign a type feedback id to the IC, since type feedback is provided
   // by the vector above.
   CallIC(ic);
 
   RecordJSReturnSite(expr);
 
   // Restore context register.
   __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
@@ skipping 1990 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64