[turbofan] Better and more sane support for tail calls

src/compiler/instruction-selector.h

 // 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.
 
 #ifndef V8_COMPILER_INSTRUCTION_SELECTOR_H_
 #define V8_COMPILER_INSTRUCTION_SELECTOR_H_
 
 #include <map>
 
 #include "src/compiler/common-operator.h"
@@ skipping 146 matching lines @@
   void MarkAsWord32(Node* node) { MarkAsRepresentation(kRepWord32, node); }
   void MarkAsWord64(Node* node) { MarkAsRepresentation(kRepWord64, node); }
   void MarkAsFloat32(Node* node) { MarkAsRepresentation(kRepFloat32, node); }
   void MarkAsFloat64(Node* node) { MarkAsRepresentation(kRepFloat64, node); }
   void MarkAsReference(Node* node) { MarkAsRepresentation(kRepTagged, node); }
 
   // Inform the register allocation of the representation of the unallocated
   // operand {op}.
   void MarkAsRepresentation(MachineType rep, const InstructionOperand& op);
 
+  enum CallBufferFlag {
+    kCallCodeImmediate = 1u << 0,
+    kCallAddressImmediate = 1u << 1,
+    kCallTail = 1u << 2
+  };
+  typedef base::Flags<CallBufferFlag> CallBufferFlags;
+
   // Initialize the call buffer with the InstructionOperands, nodes, etc,
   // corresponding
   // to the inputs and outputs of the call.
   // {call_code_immediate} to generate immediate operands to calls of code.
   // {call_address_immediate} to generate immediate operands to address calls.
   void InitializeCallBuffer(Node* call, CallBuffer* buffer,
-                            bool call_code_immediate,
-                            bool call_address_immediate);
+                            CallBufferFlags flags, int stack_param_delta = 0);
   bool IsTailCallAddressImmediate();
 
   FrameStateDescriptor* GetFrameStateDescriptor(Node* node);
 
   // ===========================================================================
   // ============= Architecture-specific graph covering methods. ===============
   // ===========================================================================
 
   // Visit nodes in the given block and generate code.
   void VisitBlock(BasicBlock* block);
@@ skipping 51 matching lines @@
   BoolVector defined_;
   BoolVector used_;
   IntVector virtual_registers_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_SELECTOR_H_