Allow HPushArgument to handle more than one argument.

src/arm64/lithium-arm64.h

Index: src/arm64/lithium-arm64.h
diff --git a/src/arm64/lithium-arm64.h b/src/arm64/lithium-arm64.h
index bca5e54c1e574eca246050ea8467341b64ce5127..72ae57db3c92819935e66ea32bd2f1278c07e45d 100644
--- a/src/arm64/lithium-arm64.h
+++ b/src/arm64/lithium-arm64.h
@@ -136,7 +136,8 @@ class LCodeGen;
   V(OsrEntry)                                   \
   V(Parameter)                                  \
   V(Power)                                      \
-  V(PushArgument)                               \
+  V(PreparePushArguments)                       \
+  V(PushArguments)                              \
   V(RegExpLiteral)                              \
   V(Return)                                     \
   V(SeqStringGetChar)                           \
@@ -2249,15 +2250,50 @@ class LPower V8_FINAL : public LTemplateInstruction<1, 2, 0> {
 };
 
 
-class LPushArgument V8_FINAL : public LTemplateInstruction<0, 1, 0> {
+class LPreparePushArguments V8_FINAL : public LTemplateInstruction<0, 0, 0> {
  public:
-  explicit LPushArgument(LOperand* value) {
-    inputs_[0] = value;
+  explicit LPreparePushArguments(int argc) : argc_(argc) {}
+
+  inline int argc() const { return argc_; }
+
+  DECLARE_CONCRETE_INSTRUCTION(PreparePushArguments, "prepare-push-arguments")
+
+ protected:
+  int argc_;
+};
+
+
+class LPushArguments V8_FINAL : public LTemplateResultInstruction<0> {
+ public:
+  explicit LPushArguments(Zone* zone,
+                          int capacity = kRecommendedMaxPushedArgs)
+      : zone_(zone), inputs_(capacity, zone) {}
+
+  LOperand* argument(int i) { return inputs_[i]; }
+  int ArgumentCount() const { return inputs_.length(); }
+
+  void AddArgument(LOperand* arg) { inputs_.Add(arg, zone_); }
+
+  DECLARE_CONCRETE_INSTRUCTION(PushArguments, "push-arguments")
+
+  // It is better to limit the number of arguments pushed simultaneously to
+  // avoid pressure on the register allocator.
+  static const int kRecommendedMaxPushedArgs = 4;
+  bool ShouldSplitPush() const {
+    return inputs_.length() >= kRecommendedMaxPushedArgs;
   }
 
-  LOperand* value() { return inputs_[0]; }
+ protected:
+  Zone* zone_;
+  ZoneList<LOperand*> inputs_;
 
-  DECLARE_CONCRETE_INSTRUCTION(PushArgument, "push-argument")
+ private:
+  // Iterator support.
+  virtual int InputCount() V8_FINAL V8_OVERRIDE { return inputs_.length(); }
+  virtual LOperand* InputAt(int i) V8_FINAL V8_OVERRIDE { return inputs_[i]; }
+
+  virtual int TempCount() V8_FINAL V8_OVERRIDE { return 0; }
+  virtual LOperand* TempAt(int i) V8_FINAL V8_OVERRIDE { return NULL; }
 };