[turbofan]: Support using push instructions for setting up tail call parameters

src/compiler/code-generator.h

Index: src/compiler/code-generator.h
diff --git a/src/compiler/code-generator.h b/src/compiler/code-generator.h
index 1083e66e023b0d350d50ba2798a8358a15cb167c..5633eafdbb0a1b795cddfd0435aa1ab0d96cbf66 100644
--- a/src/compiler/code-generator.h
+++ b/src/compiler/code-generator.h
@@ -102,6 +102,11 @@ class CodeGenerator final : public GapResolver::Assembler {
   void AssembleSourcePosition(Instruction* instr);
   void AssembleGaps(Instruction* instr);
 
+  // Returns true if a instruction needs to adjust the stack pointer before
+  // execution. The stack slot index to the empty slot above the adjusted stack
+  // pointer is returned in |slot|.
+  bool GetSlotAboveSPAfterGap(Instruction* instr, int* slot);
+
   // ===========================================================================
   // ============= Architecture-specific code generation methods. ==============
   // ===========================================================================
@@ -124,18 +129,18 @@ class CodeGenerator final : public GapResolver::Assembler {
   // to tear down a stack frame.
   void AssembleReturn();
 
-  // Generates code to deconstruct a the caller's frame, including arguments.
-  void AssembleDeconstructActivationRecord(int stack_param_delta);
-
   void AssembleDeconstructFrame();
 
   // Generates code to manipulate the stack in preparation for a tail call.
-  void AssemblePrepareTailCall(int stack_param_delta);
+  void AssemblePrepareTailCall();
 
   // Generates code to pop current frame if it is an arguments adaptor frame.
   void AssemblePopArgumentsAdaptorFrame(Register args_reg, Register scratch1,
                                         Register scratch2, Register scratch3);
 
+  void AssemblePreGaps(Instruction* instr);

[Mircea Trofin, 2016/06/30 15:32:34]

Code comment on what these do.

[danno, 2016/07/01 07:31:57]

Done.

+  void AssemblePostGaps(Instruction* instr);
+
   // ===========================================================================
   // ============== Architecture-specific gap resolver methods. ================
   // ===========================================================================
@@ -188,12 +193,6 @@ class CodeGenerator final : public GapResolver::Assembler {
   DeoptimizationExit* AddDeoptimizationExit(Instruction* instr,
                                             size_t frame_state_offset);
 
-  // Converts the delta in the number of stack parameter passed from a tail
-  // caller to the callee into the distance (in pointers) the SP must be
-  // adjusted, taking frame elision and other relevant factors into
-  // consideration.
-  int TailCallFrameStackSlotDelta(int stack_param_delta);
-
   // ===========================================================================
 
   struct DeoptimizationState : ZoneObject {