[crankshaft] Support ES6 tail call elimination.

src/x64/macro-assembler-x64.h

 // 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.
 
 #ifndef V8_X64_MACRO_ASSEMBLER_X64_H_
 #define V8_X64_MACRO_ASSEMBLER_X64_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/base/flags.h"
@@ skipping 38 matching lines @@
   kPointersToHereMaybeInteresting,
   kPointersToHereAreAlwaysInteresting
 };
 
 enum class SmiOperationConstraint {
   kPreserveSourceRegister = 1 << 0,
   kBailoutOnNoOverflow = 1 << 1,
   kBailoutOnOverflow = 1 << 2
 };
 
+enum class ReturnAddressState { kOnStack, kNotOnStack };
+
 typedef base::Flags<SmiOperationConstraint> SmiOperationConstraints;
 
 DEFINE_OPERATORS_FOR_FLAGS(SmiOperationConstraints)
 
 #ifdef DEBUG
 bool AreAliased(Register reg1,
                 Register reg2,
                 Register reg3 = no_reg,
                 Register reg4 = no_reg,
                 Register reg5 = no_reg,
@@ skipping 294 matching lines @@
   void InitializeRootRegister() {
     ExternalReference roots_array_start =
         ExternalReference::roots_array_start(isolate());
     Move(kRootRegister, roots_array_start);
     addp(kRootRegister, Immediate(kRootRegisterBias));
   }
 
   // ---------------------------------------------------------------------------
   // JavaScript invokes
 
+  // Removes current frame and its arguments from the stack preserving
+  // the arguments and a return address pushed to the stack for the next call.
+  // |ra_state| defines whether return address is already pushed to stack or
+  // not. Both |callee_args_count| and |caller_args_count_reg| do not include
+  // receiver. |callee_args_count| is not modified, |caller_args_count_reg|
+  // is trashed.
+  void PrepareForTailCall(const ParameterCount& callee_args_count,
+                          Register caller_args_count_reg, Register scratch0,
+                          Register scratch1, ReturnAddressState ra_state);
+
   // Invoke the JavaScript function code by either calling or jumping.
   void InvokeFunctionCode(Register function, Register new_target,
                           const ParameterCount& expected,
                           const ParameterCount& actual, InvokeFlag flag,
                           const CallWrapper& call_wrapper);
 
   void FloodFunctionIfStepping(Register fun, Register new_target,
                                const ParameterCount& expected,
                                const ParameterCount& actual);
 
@@ skipping 624 matching lines @@
   }
   int CallSize(Register target) {
     // Opcode: REX_opt FF /2 m64
     return (target.high_bit() != 0) ? 3 : 2;
   }
   int CallSize(const Operand& target) {
     // Opcode: REX_opt FF /2 m64
     return (target.requires_rex() ? 2 : 1) + target.operand_size();
   }
 
-  // Emit call to the code we are currently generating.
-  void CallSelf() {
-    Handle<Code> self(reinterpret_cast<Code**>(CodeObject().location()));
-    Call(self, RelocInfo::CODE_TARGET);
-  }
-
   // Non-SSE2 instructions.
   void Pextrd(Register dst, XMMRegister src, int8_t imm8);
   void Pinsrd(XMMRegister dst, Register src, int8_t imm8);
   void Pinsrd(XMMRegister dst, const Operand& src, int8_t imm8);
 
   void Lzcntq(Register dst, Register src);
   void Lzcntq(Register dst, const Operand& src);
 
   void Lzcntl(Register dst, Register src);
   void Lzcntl(Register dst, const Operand& src);
@@ skipping 720 matching lines @@
   }                                                                          \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_