[turbofan] Implement tail calls with differing stack parameter counts

src/compiler/frame.h

Index: src/compiler/frame.h
diff --git a/src/compiler/frame.h b/src/compiler/frame.h
index 2850a8c1a152e74f287bbf60129bf71e2109a9b5..32a3ea1f14885db50098a2b483d3e6cfac889961 100644
--- a/src/compiler/frame.h
+++ b/src/compiler/frame.h
@@ -17,14 +17,26 @@ namespace compiler {
 // and epilogue to compiled code.
 class Frame : public ZoneObject {
  public:
-  Frame()
-      : register_save_area_size_(0),
+  explicit Frame(bool needs_frame)
+      : needs_frame_(needs_frame),
+        register_save_area_size_(0),
         spill_slot_count_(0),
+        max_tail_call_stack_delta_(0),
         osr_stack_slot_count_(0),
         allocated_registers_(NULL),
         allocated_double_registers_(NULL) {}
 
-  inline int GetSpillSlotCount() { return spill_slot_count_; }
+  inline int GetSpillSlotCount() const { return spill_slot_count_; }
+
+  inline int GetFrameSlotCount() const {
+    if (needs_frame_ || spill_slot_count_ > 0) {
+      return std::max(spill_slot_count_, max_tail_call_stack_delta_);
+    }
+    return 0;
+  }
+
+  inline void MarkNeedsFrame() { needs_frame_ = true; }
+  inline bool NeedsFrame() const { return needs_frame_; }
 
   void SetAllocatedRegisters(BitVector* regs) {
     DCHECK(allocated_registers_ == NULL);
@@ -57,6 +69,7 @@ class Frame : public ZoneObject {
 
   int AllocateSpillSlot(int width) {
     DCHECK(width == 4 || width == 8);
+    needs_frame_ = true;
     // Skip one slot if necessary.
     if (width > kPointerSize) {
       DCHECK(width == kPointerSize * 2);
@@ -68,12 +81,22 @@ class Frame : public ZoneObject {
 
   void ReserveSpillSlots(size_t slot_count) {
     DCHECK_EQ(0, spill_slot_count_);  // can only reserve before allocation.
+    needs_frame_ = true;
     spill_slot_count_ = static_cast<int>(slot_count);
   }
 
+  void UpdateMaxTailCallStackDelta(int stack_delta) {
+    if (stack_delta > max_tail_call_stack_delta_) {
+      max_tail_call_stack_delta_ = stack_delta;
+    }
+  }
+  int max_tail_call_stack_delta() { return max_tail_call_stack_delta_; }
+
  private:
+  bool needs_frame_;
   int register_save_area_size_;
   int spill_slot_count_;
+  int max_tail_call_stack_delta_;
   int osr_stack_slot_count_;
   BitVector* allocated_registers_;
   BitVector* allocated_double_registers_;