6378256: Performance problem with System.identityHashCode in client compiler

Enabled C1 optimization to try pull out hashCode from object header, before calling into the VM.

Reviewed-by: dlong, roland, thartmann

hotspot/src/cpu/sparc/vm/sharedRuntime_sparc.cpp

@@ -2015,23 +2015,33 @@ nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,
   int vep_offset = ((intptr_t)__ pc()) - start;
 
 #ifdef COMPILER1
-  if (InlineObjectHash && method->intrinsic_id() == vmIntrinsics::_hashCode) {
+  if ((InlineObjectHash && method->intrinsic_id() == vmIntrinsics::_hashCode) || (method->intrinsic_id() == vmIntrinsics::_identityHashCode)) {
-    // Object.hashCode can pull the hashCode from the header word
+    // Object.hashCode, System.identityHashCode can pull the hashCode from the
-    // instead of doing a full VM transition once it's been computed.
+    // header word instead of doing a full VM transition once it's been computed.
-    // Since hashCode is usually polymorphic at call sites we can't do
+    // Since hashCode is usually polymorphic at call sites we can't do this
-    // this optimization at the call site without a lot of work.
+    // optimization at the call site without a lot of work.
     Label slowCase;
-    Register receiver             = O0;
+    Label done;
+    Register obj_reg              = O0;
     Register result               = O0;
     Register header               = G3_scratch;
     Register hash                 = G3_scratch; // overwrite header value with hash value
     Register mask                 = G1;         // to get hash field from header
 
+    // Unlike for Object.hashCode, System.identityHashCode is static method and
+    // gets object as argument instead of the receiver.
+    if (method->intrinsic_id() == vmIntrinsics::_identityHashCode) {
+      assert(method->is_static(), "method should be static");
+      // return 0 for null reference input
+      __ br_null(obj_reg, false, Assembler::pn, done);
+      __ delayed()->mov(obj_reg, hash);
+    }
+
     // Read the header and build a mask to get its hash field.  Give up if the object is not unlocked.
     // We depend on hash_mask being at most 32 bits and avoid the use of
     // hash_mask_in_place because it could be larger than 32 bits in a 64-bit
     // vm: see markOop.hpp.
-    __ ld_ptr(receiver, oopDesc::mark_offset_in_bytes(), header);
+    __ ld_ptr(obj_reg, oopDesc::mark_offset_in_bytes(), header);
     __ sethi(markOopDesc::hash_mask, mask);
     __ btst(markOopDesc::unlocked_value, header);
     __ br(Assembler::zero, false, Assembler::pn, slowCase);
@@ -2054,6 +2064,7 @@ nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,
     __ delayed()->nop();
 
     // leaf return.
+    __ bind(done);
     __ retl();
     __ delayed()->mov(hash, result);
     __ bind(slowCase);

hotspot/src/cpu/x86/vm/sharedRuntime_x86.cpp

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2016, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "asm/macroAssembler.hpp"
+#include "runtime/sharedRuntime.hpp"
+#include "vmreg_x86.inline.hpp"
+#ifdef COMPILER1
+#include "c1/c1_Runtime1.hpp"
+#endif //COMPILER1
+
+#define __ masm->
+
+#ifdef COMPILER1
+// ---------------------------------------------------------------------------
+// Object.hashCode, System.identityHashCode can pull the hashCode from the
+// header word instead of doing a full VM transition once it's been computed.
+// Since hashCode is usually polymorphic at call sites we can't do this
+// optimization at the call site without a lot of work.
+void SharedRuntime::inline_check_hashcode_from_object_header(MacroAssembler* masm,
+                                 methodHandle method,
+                                 Register obj_reg,
+                                 Register result) {
+  Label slowCase;
+
+  // Unlike for Object.hashCode, System.identityHashCode is static method and
+  // gets object as argument instead of the receiver.
+  if (method->intrinsic_id() == vmIntrinsics::_identityHashCode) {
+    Label Continue;
+    // return 0 for null reference input
+    __ cmpptr(obj_reg, (int32_t)NULL_WORD);
+    __ jcc(Assembler::notEqual, Continue);
+    __ xorptr(result, result);
+    __ ret(0);
+    __ bind(Continue);
+  }
+
+  __ movptr(result, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
+
+  // check if locked
+  __ testptr(result, markOopDesc::unlocked_value);
+  __ jcc(Assembler::zero, slowCase);
+
+  if (UseBiasedLocking) {
+    // Check if biased and fall through to runtime if so
+    __ testptr(result, markOopDesc::biased_lock_bit_in_place);
+    __ jcc(Assembler::notZero, slowCase);
+  }
+
+  // get hash
+#ifdef _LP64
+  // Read the header and build a mask to get its hash field.
+  // Depend on hash_mask being at most 32 bits and avoid the use of hash_mask_in_place
+  // because it could be larger than 32 bits in a 64-bit vm. See markOop.hpp.
+  __ shrptr(result, markOopDesc::hash_shift);
+  __ andptr(result, markOopDesc::hash_mask);
+#else
+  __ andptr(result, markOopDesc::hash_mask_in_place);
+#endif //_LP64
+
+  // test if hashCode exists
+  __ jcc(Assembler::zero, slowCase);
+#ifndef _LP64
+  __ shrptr(result, markOopDesc::hash_shift);
+#endif
+  __ ret(0);
+  __ bind(slowCase);
+}
+#endif //COMPILER1
+

hotspot/src/cpu/x86/vm/sharedRuntime_x86_32.cpp

@@ -1754,34 +1754,10 @@ nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,
   int vep_offset = ((intptr_t)__ pc()) - start;
 
 #ifdef COMPILER1
-  if (InlineObjectHash && method->intrinsic_id() == vmIntrinsics::_hashCode) {
+  // For Object.hashCode, System.identityHashCode try to pull hashCode from object header if available.
-    // Object.hashCode can pull the hashCode from the header word
+  if ((InlineObjectHash && method->intrinsic_id() == vmIntrinsics::_hashCode) || (method->intrinsic_id() == vmIntrinsics::_identityHashCode)) {
-    // instead of doing a full VM transition once it's been computed.
+    inline_check_hashcode_from_object_header(masm, method, rcx /*obj_reg*/, rax /*result*/);
-    // Since hashCode is usually polymorphic at call sites we can't do
+   }
-    // this optimization at the call site without a lot of work.
-    Label slowCase;
-    Register receiver = rcx;
-    Register result = rax;
-    __ movptr(result, Address(receiver, oopDesc::mark_offset_in_bytes()));
-
-    // check if locked
-    __ testptr(result, markOopDesc::unlocked_value);
-    __ jcc (Assembler::zero, slowCase);
-
-    if (UseBiasedLocking) {
-      // Check if biased and fall through to runtime if so
-      __ testptr(result, markOopDesc::biased_lock_bit_in_place);
-      __ jcc (Assembler::notZero, slowCase);
-    }
-
-    // get hash
-    __ andptr(result, markOopDesc::hash_mask_in_place);
-    // test if hashCode exists
-    __ jcc  (Assembler::zero, slowCase);
-    __ shrptr(result, markOopDesc::hash_shift);
-    __ ret(0);
-    __ bind (slowCase);
-  }
 #endif // COMPILER1
 
   // The instruction at the verified entry point must be 5 bytes or longer

hotspot/src/cpu/x86/vm/sharedRuntime_x86_64.cpp

@@ -2058,6 +2058,13 @@ nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,
 
   int vep_offset = ((intptr_t)__ pc()) - start;
 
+#ifdef COMPILER1
+  // For Object.hashCode, System.identityHashCode try to pull hashCode from object header if available.
+  if ((InlineObjectHash && method->intrinsic_id() == vmIntrinsics::_hashCode) || (method->intrinsic_id() == vmIntrinsics::_identityHashCode)) {
+    inline_check_hashcode_from_object_header(masm, method, j_rarg0 /*obj_reg*/, rax /*result*/);
+  }
+#endif // COMPILER1
+
   // The instruction at the verified entry point must be 5 bytes or longer
   // because it can be patched on the fly by make_non_entrant. The stack bang
   // instruction fits that requirement.

hotspot/src/share/vm/runtime/sharedRuntime.hpp

@@ -359,6 +359,11 @@ class SharedRuntime: AllStatic {
   static address clean_opt_virtual_call_entry();
   static address clean_static_call_entry();
 
+#if defined(X86) && defined(COMPILER1)
+  // For Object.hashCode, System.identityHashCode try to pull hashCode from object header if available.
+  static void inline_check_hashcode_from_object_header(MacroAssembler* masm, methodHandle method, Register obj_reg, Register result);
+#endif // X86 && COMPILER1
+
  public:
 
   // Read the array of BasicTypes from a Java signature, and compute where