# HG changeset patch
# User rkennke
# Date 1541006145 -3600
#      Wed Oct 31 18:15:45 2018 +0100
# Node ID 6111932feaf38b4770f6c9977e377bf9701d47c8
# Parent  896e80158d355bb8aebbf1b7193bfe609551912e
8213199: GC abstraction for Assembler::needs_explicit_null_check()

diff --git a/src/hotspot/cpu/aarch64/gc/shared/barrierSetAssembler_aarch64.hpp b/src/hotspot/cpu/aarch64/gc/shared/barrierSetAssembler_aarch64.hpp
--- a/src/hotspot/cpu/aarch64/gc/shared/barrierSetAssembler_aarch64.hpp
+++ b/src/hotspot/cpu/aarch64/gc/shared/barrierSetAssembler_aarch64.hpp
@@ -72,6 +72,8 @@
     Label&   slow_case                 // continuation point if fast allocation fails
   );
   virtual void barrier_stubs_init() {}
+
+  virtual bool needs_explicit_null_check(intptr_t offset);
 };
 
 #endif // CPU_AARCH64_GC_SHARED_BARRIERSETASSEMBLER_AARCH64_HPP
diff --git a/src/hotspot/cpu/arm/gc/shared/barrierSetAssembler_arm.hpp b/src/hotspot/cpu/arm/gc/shared/barrierSetAssembler_arm.hpp
--- a/src/hotspot/cpu/arm/gc/shared/barrierSetAssembler_arm.hpp
+++ b/src/hotspot/cpu/arm/gc/shared/barrierSetAssembler_arm.hpp
@@ -72,6 +72,8 @@
   virtual void resolve(MacroAssembler* masm, DecoratorSet decorators, Register obj) {
     // Default implementation does not need to do anything.
   }
+
+  virtual bool needs_explicit_null_check(intptr_t offset);
 };
 
 #endif // CPU_ARM_GC_SHARED_BARRIERSETASSEMBLER_ARM_HPP
diff --git a/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.hpp b/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.hpp
--- a/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.hpp
+++ b/src/hotspot/cpu/ppc/gc/shared/barrierSetAssembler_ppc.hpp
@@ -50,6 +50,8 @@
   virtual void resolve_jobject(MacroAssembler* masm, Register value, Register tmp1, Register tmp2, bool needs_frame);
 
   virtual void barrier_stubs_init() {}
+
+  virtual bool needs_explicit_null_check(intptr_t offset);
 };
 
 #endif // CPU_PPC_GC_SHARED_BARRIERSETASSEMBLER_PPC_HPP
diff --git a/src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.hpp b/src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.hpp
--- a/src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.hpp
+++ b/src/hotspot/cpu/s390/gc/shared/barrierSetAssembler_s390.hpp
@@ -47,6 +47,8 @@
   virtual void resolve_jobject(MacroAssembler* masm, Register value, Register tmp1, Register tmp2);
 
   virtual void barrier_stubs_init() {}
+
+  virtual bool needs_explicit_null_check(intptr_t offset);
 };
 
 #endif // CPU_S390_GC_SHARED_BARRIERSETASSEMBLER_S390_HPP
diff --git a/src/hotspot/cpu/sparc/gc/shared/barrierSetAssembler_sparc.hpp b/src/hotspot/cpu/sparc/gc/shared/barrierSetAssembler_sparc.hpp
--- a/src/hotspot/cpu/sparc/gc/shared/barrierSetAssembler_sparc.hpp
+++ b/src/hotspot/cpu/sparc/gc/shared/barrierSetAssembler_sparc.hpp
@@ -49,6 +49,8 @@
                                              Register obj, Register tmp, Label& slowpath);
 
   virtual void barrier_stubs_init() {}
+
+  virtual bool needs_explicit_null_check(intptr_t offset);
 };
 
 #endif // CPU_SPARC_GC_SHARED_BARRIERSETASSEMBLER_SPARC_HPP
diff --git a/src/hotspot/cpu/x86/gc/shared/barrierSetAssembler_x86.hpp b/src/hotspot/cpu/x86/gc/shared/barrierSetAssembler_x86.hpp
--- a/src/hotspot/cpu/x86/gc/shared/barrierSetAssembler_x86.hpp
+++ b/src/hotspot/cpu/x86/gc/shared/barrierSetAssembler_x86.hpp
@@ -85,6 +85,8 @@
   virtual void barrier_stubs_init() {}
 
   virtual void nmethod_entry_barrier(MacroAssembler* masm);
+
+  virtual bool needs_explicit_null_check(intptr_t offset);
 };
 
 #endif // CPU_X86_GC_SHARED_BARRIERSETASSEMBLER_X86_HPP
diff --git a/src/hotspot/share/asm/assembler.cpp b/src/hotspot/share/asm/assembler.cpp
--- a/src/hotspot/share/asm/assembler.cpp
+++ b/src/hotspot/share/asm/assembler.cpp
@@ -308,20 +308,5 @@
 }
 
 bool MacroAssembler::needs_explicit_null_check(intptr_t offset) {
-  // Exception handler checks the nmethod's implicit null checks table
-  // only when this method returns false.
-#ifdef _LP64
-  if (UseCompressedOops && Universe::narrow_oop_base() != NULL) {
-    assert (Universe::heap() != NULL, "java heap should be initialized");
-    // The first page after heap_base is unmapped and
-    // the 'offset' is equal to [heap_base + offset] for
-    // narrow oop implicit null checks.
-    uintptr_t base = (uintptr_t)Universe::narrow_oop_base();
-    if ((uintptr_t)offset >= base) {
-      // Normalize offset for the next check.
-      offset = (intptr_t)(pointer_delta((void*)offset, (void*)base, 1));
-    }
-  }
-#endif
-  return offset < 0 || os::vm_page_size() <= offset;
+  return BarrierSet::barrier_set()->barrier_set_assembler()->needs_explicit_null_check(offset);
 }
diff --git a/src/hotspot/share/gc/shared/barrierSetAssembler.cpp b/src/hotspot/share/gc/shared/barrierSetAssembler.cpp
new file mode 100644
--- /dev/null
+++ b/src/hotspot/share/gc/shared/barrierSetAssembler.cpp
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2018, 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 "gc/shared/barrierSetAssembler.hpp"
+#include "memory/universe.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+bool BarrierSetAssembler::needs_explicit_null_check(intptr_t offset) {
+  // Exception handler checks the nmethod's implicit null checks table
+  // only when this method returns false.
+#ifdef _LP64
+  if (UseCompressedOops && Universe::narrow_oop_base() != NULL) {
+    assert (Universe::heap() != NULL, "java heap should be initialized");
+    // The first page after heap_base is unmapped and
+    // the 'offset' is equal to [heap_base + offset] for
+    // narrow oop implicit null checks.
+    uintptr_t base = (uintptr_t)Universe::narrow_oop_base();
+    if ((uintptr_t)offset >= base) {
+      // Normalize offset for the next check.
+      offset = (intptr_t)(pointer_delta((void*)offset, (void*)base, 1));
+    }
+  }
+#endif
+  return offset < 0 || os::vm_page_size() <= offset;
+}