--- a/hotspot/src/cpu/x86/vm/macroAssembler_x86.cpp	Wed Aug 14 15:12:00 2013 -0700
+++ b/hotspot/src/cpu/x86/vm/macroAssembler_x86.cpp	Thu Aug 15 20:04:10 2013 -0400
@@ -30,6 +30,7 @@
 #include "interpreter/interpreter.hpp"
 #include "memory/cardTableModRefBS.hpp"
 #include "memory/resourceArea.hpp"
+#include "memory/universe.hpp"
 #include "prims/methodHandles.hpp"
 #include "runtime/biasedLocking.hpp"
 #include "runtime/interfaceSupport.hpp"
@@ -4810,23 +4811,8 @@
 }
 
 void MacroAssembler::load_prototype_header(Register dst, Register src) {
-#ifdef _LP64
-  if (UseCompressedKlassPointers) {
-    assert (Universe::heap() != NULL, "java heap should be initialized");
-    movl(dst, Address(src, oopDesc::klass_offset_in_bytes()));
-    if (Universe::narrow_klass_shift() != 0) {
-      assert(LogKlassAlignmentInBytes == Universe::narrow_klass_shift(), "decode alg wrong");
-      assert(LogKlassAlignmentInBytes == Address::times_8, "klass not aligned on 64bits?");
-      movq(dst, Address(r12_heapbase, dst, Address::times_8, Klass::prototype_header_offset()));
-    } else {
-      movq(dst, Address(dst, Klass::prototype_header_offset()));
-    }
-  } else
-#endif
-  {
-    movptr(dst, Address(src, oopDesc::klass_offset_in_bytes()));
-    movptr(dst, Address(dst, Klass::prototype_header_offset()));
-  }
+  load_klass(dst, src);
+  movptr(dst, Address(dst, Klass::prototype_header_offset()));
 }
 
 void MacroAssembler::store_klass(Register dst, Register src) {
@@ -4914,7 +4900,7 @@
 
 #ifdef ASSERT
 void MacroAssembler::verify_heapbase(const char* msg) {
-  assert (UseCompressedOops || UseCompressedKlassPointers, "should be compressed");
+  assert (UseCompressedOops, "should be compressed");
   assert (Universe::heap() != NULL, "java heap should be initialized");
   if (CheckCompressedOops) {
     Label ok;
@@ -5058,69 +5044,80 @@
 }
 
 void MacroAssembler::encode_klass_not_null(Register r) {
-  assert(Metaspace::is_initialized(), "metaspace should be initialized");
-#ifdef ASSERT
-  verify_heapbase("MacroAssembler::encode_klass_not_null: heap base corrupted?");
-#endif
-  if (Universe::narrow_klass_base() != NULL) {
-    subq(r, r12_heapbase);
-  }
+  assert(Universe::narrow_klass_base() != NULL, "Base should be initialized");
+  // Use r12 as a scratch register in which to temporarily load the narrow_klass_base.
+  assert(r != r12_heapbase, "Encoding a klass in r12");
+  mov64(r12_heapbase, (int64_t)Universe::narrow_klass_base());
+  subq(r, r12_heapbase);
   if (Universe::narrow_klass_shift() != 0) {
     assert (LogKlassAlignmentInBytes == Universe::narrow_klass_shift(), "decode alg wrong");
     shrq(r, LogKlassAlignmentInBytes);
   }
+  reinit_heapbase();
 }
 
 void MacroAssembler::encode_klass_not_null(Register dst, Register src) {
-  assert(Metaspace::is_initialized(), "metaspace should be initialized");
-#ifdef ASSERT
-  verify_heapbase("MacroAssembler::encode_klass_not_null2: heap base corrupted?");
-#endif
-  if (dst != src) {
-    movq(dst, src);
-  }
-  if (Universe::narrow_klass_base() != NULL) {
-    subq(dst, r12_heapbase);
-  }
-  if (Universe::narrow_klass_shift() != 0) {
-    assert (LogKlassAlignmentInBytes == Universe::narrow_klass_shift(), "decode alg wrong");
-    shrq(dst, LogKlassAlignmentInBytes);
-  }
-}
-
+  if (dst == src) {
+    encode_klass_not_null(src);
+  } else {
+    mov64(dst, (int64_t)Universe::narrow_klass_base());
+    negq(dst);
+    addq(dst, src);
+    if (Universe::narrow_klass_shift() != 0) {
+      assert (LogKlassAlignmentInBytes == Universe::narrow_klass_shift(), "decode alg wrong");
+      shrq(dst, LogKlassAlignmentInBytes);
+    }
+  }
+}
+
+// Function instr_size_for_decode_klass_not_null() counts the instructions
+// generated by decode_klass_not_null(register r) and reinit_heapbase(),
+// when (Universe::heap() != NULL).  Hence, if the instructions they
+// generate change, then this method needs to be updated.
+int MacroAssembler::instr_size_for_decode_klass_not_null() {
+  assert (UseCompressedKlassPointers, "only for compressed klass ptrs");
+  // mov64 + addq + shlq? + mov64  (for reinit_heapbase()).
+  return (Universe::narrow_klass_shift() == 0 ? 20 : 24);
+}
+
+// !!! If the instructions that get generated here change then function
+// instr_size_for_decode_klass_not_null() needs to get updated.
 void  MacroAssembler::decode_klass_not_null(Register r) {
-  assert(Metaspace::is_initialized(), "metaspace should be initialized");
   // Note: it will change flags
+  assert(Universe::narrow_klass_base() != NULL, "Base should be initialized");
   assert (UseCompressedKlassPointers, "should only be used for compressed headers");
+  assert(r != r12_heapbase, "Decoding a klass in r12");
   // Cannot assert, unverified entry point counts instructions (see .ad file)
   // vtableStubs also counts instructions in pd_code_size_limit.
   // Also do not verify_oop as this is called by verify_oop.
   if (Universe::narrow_klass_shift() != 0) {
     assert(LogKlassAlignmentInBytes == Universe::narrow_klass_shift(), "decode alg wrong");
     shlq(r, LogKlassAlignmentInBytes);
-    if (Universe::narrow_klass_base() != NULL) {
-      addq(r, r12_heapbase);
-    }
-  } else {
-    assert (Universe::narrow_klass_base() == NULL, "sanity");
-  }
+  }
+  // Use r12 as a scratch register in which to temporarily load the narrow_klass_base.
+  mov64(r12_heapbase, (int64_t)Universe::narrow_klass_base());
+  addq(r, r12_heapbase);
+  reinit_heapbase();
 }
 
 void  MacroAssembler::decode_klass_not_null(Register dst, Register src) {
-  assert(Metaspace::is_initialized(), "metaspace should be initialized");
   // Note: it will change flags
+  assert(Universe::narrow_klass_base() != NULL, "Base should be initialized");
   assert (UseCompressedKlassPointers, "should only be used for compressed headers");
-  // Cannot assert, unverified entry point counts instructions (see .ad file)
-  // vtableStubs also counts instructions in pd_code_size_limit.
-  // Also do not verify_oop as this is called by verify_oop.
-  if (Universe::narrow_klass_shift() != 0) {
-    assert(LogKlassAlignmentInBytes == Universe::narrow_klass_shift(), "decode alg wrong");
-    assert(LogKlassAlignmentInBytes == Address::times_8, "klass not aligned on 64bits?");
-    leaq(dst, Address(r12_heapbase, src, Address::times_8, 0));
+  if (dst == src) {
+    decode_klass_not_null(dst);
   } else {
-    assert (Universe::narrow_klass_base() == NULL, "sanity");
-    if (dst != src) {
-      movq(dst, src);
+    // Cannot assert, unverified entry point counts instructions (see .ad file)
+    // vtableStubs also counts instructions in pd_code_size_limit.
+    // Also do not verify_oop as this is called by verify_oop.
+
+    mov64(dst, (int64_t)Universe::narrow_klass_base());
+    if (Universe::narrow_klass_shift() != 0) {
+      assert(LogKlassAlignmentInBytes == Universe::narrow_klass_shift(), "decode alg wrong");
+      assert(LogKlassAlignmentInBytes == Address::times_8, "klass not aligned on 64bits?");
+      leaq(dst, Address(dst, src, Address::times_8, 0));
+    } else {
+      addq(dst, src);
     }
   }
 }
@@ -5148,7 +5145,7 @@
   assert (oop_recorder() != NULL, "this assembler needs an OopRecorder");
   int klass_index = oop_recorder()->find_index(k);
   RelocationHolder rspec = metadata_Relocation::spec(klass_index);
-  mov_narrow_oop(dst, oopDesc::encode_klass(k), rspec);
+  mov_narrow_oop(dst, Klass::encode_klass(k), rspec);
 }
 
 void  MacroAssembler::set_narrow_klass(Address dst, Klass* k) {
@@ -5156,7 +5153,7 @@
   assert (oop_recorder() != NULL, "this assembler needs an OopRecorder");
   int klass_index = oop_recorder()->find_index(k);
   RelocationHolder rspec = metadata_Relocation::spec(klass_index);
-  mov_narrow_oop(dst, oopDesc::encode_klass(k), rspec);
+  mov_narrow_oop(dst, Klass::encode_klass(k), rspec);
 }
 
 void  MacroAssembler::cmp_narrow_oop(Register dst, jobject obj) {
@@ -5182,7 +5179,7 @@
   assert (oop_recorder() != NULL, "this assembler needs an OopRecorder");
   int klass_index = oop_recorder()->find_index(k);
   RelocationHolder rspec = metadata_Relocation::spec(klass_index);
-  Assembler::cmp_narrow_oop(dst, oopDesc::encode_klass(k), rspec);
+  Assembler::cmp_narrow_oop(dst, Klass::encode_klass(k), rspec);
 }
 
 void  MacroAssembler::cmp_narrow_klass(Address dst, Klass* k) {
@@ -5190,14 +5187,23 @@
   assert (oop_recorder() != NULL, "this assembler needs an OopRecorder");
   int klass_index = oop_recorder()->find_index(k);
   RelocationHolder rspec = metadata_Relocation::spec(klass_index);
-  Assembler::cmp_narrow_oop(dst, oopDesc::encode_klass(k), rspec);
+  Assembler::cmp_narrow_oop(dst, Klass::encode_klass(k), rspec);
 }
 
 void MacroAssembler::reinit_heapbase() {
   if (UseCompressedOops || UseCompressedKlassPointers) {
-    movptr(r12_heapbase, ExternalAddress((address)Universe::narrow_ptrs_base_addr()));
-  }
-}
+    if (Universe::heap() != NULL) {
+      if (Universe::narrow_oop_base() == NULL) {
+        MacroAssembler::xorptr(r12_heapbase, r12_heapbase);
+      } else {
+        mov64(r12_heapbase, (int64_t)Universe::narrow_ptrs_base());
+      }
+    } else {
+      movptr(r12_heapbase, ExternalAddress((address)Universe::narrow_ptrs_base_addr()));
+    }
+  }
+}
+
 #endif // _LP64