Encapsulate megamorphic load/tail-call in hydrogen

src/arm64/lithium-codegen-arm64.cc

Index: src/arm64/lithium-codegen-arm64.cc
diff --git a/src/arm64/lithium-codegen-arm64.cc b/src/arm64/lithium-codegen-arm64.cc
index 8c9507c9817a92311846c3b8624bfcf2b4175a19..904eecd2e10a0b2672249241dabf62b2d28ddc9a 100644
--- a/src/arm64/lithium-codegen-arm64.cc
+++ b/src/arm64/lithium-codegen-arm64.cc
@@ -9,6 +9,7 @@
 #include "src/base/bits.h"
 #include "src/code-stubs.h"
 #include "src/hydrogen-osr.h"
+#include "src/ic/stub-cache.h"
 
 namespace v8 {
 namespace internal {
@@ -2037,6 +2038,34 @@ void LCodeGen::CallKnownFunction(Handle<JSFunction> function,
 }
 
 
+void LCodeGen::DoTailCallThroughMegamorphicCache(
+    LTailCallThroughMegamorphicCache* instr) {
+  Register receiver = ToRegister(instr->receiver());
+  Register name = ToRegister(instr->name());
+  DCHECK(receiver.is(LoadDescriptor::ReceiverRegister()));
+  DCHECK(name.is(LoadDescriptor::NameRegister()));
+  DCHECK(receiver.is(x1));
+  DCHECK(name.is(x2));
+
+  Register scratch = x3;
+  Register extra = x4;
+  Register extra2 = x5;
+  Register extra3 = x6;
+
+  // Important for the tail-call.
+  bool must_teardown_frame = NeedsEagerFrame();
+
+  // The probe will tail call to a handler if found.
+  isolate()->stub_cache()->GenerateProbe(masm(), instr->hydrogen()->flags(),
+                                         must_teardown_frame, receiver, name,
+                                         scratch, extra, extra2, extra3);
+
+  // Tail call to miss if we ended up here.
+  if (must_teardown_frame) __ LeaveFrame(StackFrame::INTERNAL);
+  LoadIC::GenerateMiss(masm());
+}
+
+
 void LCodeGen::DoCallWithDescriptor(LCallWithDescriptor* instr) {
   DCHECK(instr->IsMarkedAsCall());
   DCHECK(ToRegister(instr->result()).Is(x0));