8174962: Better interface invocations

Reviewed-by: jrose, coleenp, ahgross, acorn, vlivanov

1 files changed, 18 insertions, 9 deletions

diff --git a/src/cpu/x86/vm/macroAssembler_x86.cpp b/src/cpu/x86/vm/macroAssembler_x86.cpp
index 9711089a4..9664c6b52 100644
--- a/src/cpu/x86/vm/macroAssembler_x86.cpp
+++ b/src/cpu/x86/vm/macroAssembler_x86.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -4853,8 +4853,13 @@ void MacroAssembler::lookup_interface_method(Register recv_klass,
                                              RegisterOrConstant itable_index,
                                              Register method_result,
                                              Register scan_temp,
-                                             Label& L_no_such_interface) {
-  assert_different_registers(recv_klass, intf_klass, method_result, scan_temp);
+                                             Label& L_no_such_interface,
+                                             bool return_method) {
+  assert_different_registers(recv_klass, intf_klass, scan_temp);
+  assert_different_registers(method_result, intf_klass, scan_temp);
+  assert(recv_klass != method_result || !return_method,
+         "recv_klass can be destroyed when method isn't needed");
+
   assert(itable_index.is_constant() || itable_index.as_register() == method_result,
          "caller must use same register for non-constant itable index as for method");
 
@@ -4876,9 +4881,11 @@ void MacroAssembler::lookup_interface_method(Register recv_klass,
     round_to(scan_temp, BytesPerLong);
   }
 
-  // Adjust recv_klass by scaled itable_index, so we can free itable_index.
-  assert(itableMethodEntry::size() * wordSize == wordSize, "adjust the scaling in the code below");
-  lea(recv_klass, Address(recv_klass, itable_index, Address::times_ptr, itentry_off));
+  if (return_method) {
+    // Adjust recv_klass by scaled itable_index, so we can free itable_index.
+    assert(itableMethodEntry::size() * wordSize == wordSize, "adjust the scaling in the code below");
+    lea(recv_klass, Address(recv_klass, itable_index, Address::times_ptr, itentry_off));
+  }
 
   // for (scan = klass->itable(); scan->interface() != NULL; scan += scan_step) {
   //   if (scan->interface() == intf) {
@@ -4912,9 +4919,11 @@ void MacroAssembler::lookup_interface_method(Register recv_klass,
 
   bind(found_method);
 
-  // Got a hit.
-  movl(scan_temp, Address(scan_temp, itableOffsetEntry::offset_offset_in_bytes()));
-  movptr(method_result, Address(recv_klass, scan_temp, Address::times_1));
+  if (return_method) {
+    // Got a hit.
+    movl(scan_temp, Address(scan_temp, itableOffsetEntry::offset_offset_in_bytes()));
+    movptr(method_result, Address(recv_klass, scan_temp, Address::times_1));
+  }
 }