diff --git a/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp b/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp
index 2d9355c8ee6ca..2d6f78db85223 100644
--- a/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp
+++ b/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp
@@ -175,7 +175,7 @@ int MacroAssembler::patch_oop(address insn_addr, address o) {
// instruction.
if (Instruction_aarch64::extract(insn, 31, 21) == 0b11010010101) {
// Move narrow OOP
- narrowOop n = CompressedOops::encode((oop)o);
+ uint32_t n = CompressedOops::narrow_oop_value((oop)o);
Instruction_aarch64::patch(insn_addr, 20, 5, n >> 16);
Instruction_aarch64::patch(insn_addr+4, 20, 5, n & 0xffff);
instructions = 2;
diff --git a/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp b/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp
index c3f39861dc772..3d3c39cf5d58d 100644
--- a/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp
+++ b/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp
@@ -220,8 +220,9 @@ address MacroAssembler::patch_set_narrow_oop(address a, address bound, narrowOop
}
assert(inst1_found, "inst is not lis");
- int xc = (data >> 16) & 0xffff;
- int xd = (data >> 0) & 0xffff;
+ uint32_t data_value = CompressedOops::narrow_oop_value(data);
+ int xc = (data_value >> 16) & 0xffff;
+ int xd = (data_value >> 0) & 0xffff;
set_imm((int *)inst1_addr, (short)(xc)); // see enc_load_con_narrow_hi/_lo
set_imm((int *)inst2_addr, (xd)); // unsigned int
@@ -254,7 +255,7 @@ narrowOop MacroAssembler::get_narrow_oop(address a, address bound) {
uint xl = ((unsigned int) (get_imm(inst2_addr, 0) & 0xffff));
uint xh = (((get_imm(inst1_addr, 0)) & 0xffff) << 16);
- return (int) (xl | xh);
+ return CompressedOops::narrow_oop_cast(xl | xh);
}
#endif // _LP64
diff --git a/src/hotspot/cpu/ppc/nativeInst_ppc.cpp b/src/hotspot/cpu/ppc/nativeInst_ppc.cpp
index 23e8ccac6e6f3..fbe956322a6b2 100644
--- a/src/hotspot/cpu/ppc/nativeInst_ppc.cpp
+++ b/src/hotspot/cpu/ppc/nativeInst_ppc.cpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2019 SAP SE. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
@@ -196,7 +196,7 @@ intptr_t NativeMovConstReg::data() const {
CodeBlob* cb = CodeCache::find_blob_unsafe(addr);
if (MacroAssembler::is_set_narrow_oop(addr, cb->content_begin())) {
- narrowOop no = (narrowOop)MacroAssembler::get_narrow_oop(addr, cb->content_begin());
+ narrowOop no = MacroAssembler::get_narrow_oop(addr, cb->content_begin());
return cast_from_oop<intptr_t>(CompressedOops::decode(no));
} else {
assert(MacroAssembler::is_load_const_from_method_toc_at(addr), "must be load_const_from_pool");
@@ -293,10 +293,11 @@ void NativeMovConstReg::set_data(intptr_t data) {
void NativeMovConstReg::set_narrow_oop(narrowOop data, CodeBlob *code /* = NULL */) {
address inst2_addr = addr_at(0);
CodeBlob* cb = (code) ? code : CodeCache::find_blob(instruction_address());
- if (MacroAssembler::get_narrow_oop(inst2_addr, cb->content_begin()) == (long)data)
+ if (MacroAssembler::get_narrow_oop(inst2_addr, cb->content_begin()) == data) {
return;
+ }
const address inst1_addr =
- MacroAssembler::patch_set_narrow_oop(inst2_addr, cb->content_begin(), (long)data);
+ MacroAssembler::patch_set_narrow_oop(inst2_addr, cb->content_begin(), data);
assert(inst1_addr != NULL && inst1_addr < inst2_addr, "first instruction must be found");
const int range = inst2_addr - inst1_addr + BytesPerInstWord;
ICache::ppc64_flush_icache_bytes(inst1_addr, range);
diff --git a/src/hotspot/cpu/ppc/relocInfo_ppc.cpp b/src/hotspot/cpu/ppc/relocInfo_ppc.cpp
index 6fed8163863c9..f940a7e0fb82e 100644
--- a/src/hotspot/cpu/ppc/relocInfo_ppc.cpp
+++ b/src/hotspot/cpu/ppc/relocInfo_ppc.cpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2015 SAP SE. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
@@ -58,7 +58,9 @@ void Relocation::pd_set_data_value(address x, intptr_t o, bool verify_only) {
assert(type() == relocInfo::oop_type || type() == relocInfo::metadata_type,
"how to encode else?");
narrowOop no = (type() == relocInfo::oop_type) ?
- CompressedOops::encode((oop)x) : CompressedKlassPointers::encode((Klass*)x);
+ CompressedOops::encode((oop)x) :
+ // Type punning compressed klass pointer as narrowOop.
+ CompressedOops::narrow_oop_cast(CompressedKlassPointers::encode((Klass*)x));
nativeMovConstReg_at(addr())->set_narrow_oop(no, code());
}
} else {
diff --git a/src/hotspot/cpu/s390/macroAssembler_s390.cpp b/src/hotspot/cpu/s390/macroAssembler_s390.cpp
index d68aa281f86c1..c71a15daa7cb0 100644
--- a/src/hotspot/cpu/s390/macroAssembler_s390.cpp
+++ b/src/hotspot/cpu/s390/macroAssembler_s390.cpp
@@ -1163,7 +1163,7 @@ void MacroAssembler::load_const_32to64(Register t, int64_t x, bool sign_extend)
// Load narrow oop constant, no decompression.
void MacroAssembler::load_narrow_oop(Register t, narrowOop a) {
assert(UseCompressedOops, "must be on to call this method");
- load_const_32to64(t, a, false /*sign_extend*/);
+ load_const_32to64(t, CompressedOops::narrow_oop_value(a), false /*sign_extend*/);
}
// Load narrow klass constant, compression required.
@@ -1181,7 +1181,7 @@ void MacroAssembler::load_narrow_klass(Register t, Klass* k) {
void MacroAssembler::compare_immediate_narrow_oop(Register oop1, narrowOop oop2) {
assert(UseCompressedOops, "must be on to call this method");
- Assembler::z_clfi(oop1, oop2);
+ Assembler::z_clfi(oop1, CompressedOops::narrow_oop_value(oop2));
}
// Compare narrow oop in reg with narrow oop constant, no decompression.
@@ -1273,9 +1273,7 @@ int MacroAssembler::patch_compare_immediate_32(address pos, int64_t np) {
// The passed ptr must NOT be in compressed format!
int MacroAssembler::patch_load_narrow_oop(address pos, oop o) {
assert(UseCompressedOops, "Can only patch compressed oops");
-
- narrowOop no = CompressedOops::encode(o);
- return patch_load_const_32to64(pos, no);
+ return patch_load_const_32to64(pos, CompressedOops::narrow_oop_value(o));
}
// Patching the immediate value of CPU version dependent load_narrow_klass sequence.
@@ -1291,9 +1289,7 @@ int MacroAssembler::patch_load_narrow_klass(address pos, Klass* k) {
// The passed ptr must NOT be in compressed format!
int MacroAssembler::patch_compare_immediate_narrow_oop(address pos, oop o) {
assert(UseCompressedOops, "Can only patch compressed oops");
-
- narrowOop no = CompressedOops::encode(o);
- return patch_compare_immediate_32(pos, no);
+ return patch_compare_immediate_32(pos, CompressedOops::narrow_oop_value(o));
}
// Patching the immediate value of CPU version dependent compare_immediate_narrow_klass sequence.
diff --git a/src/hotspot/cpu/x86/relocInfo_x86.cpp b/src/hotspot/cpu/x86/relocInfo_x86.cpp
index 6bdb0a2ee067a..794bfb7bf3e4c 100644
--- a/src/hotspot/cpu/x86/relocInfo_x86.cpp
+++ b/src/hotspot/cpu/x86/relocInfo_x86.cpp
@@ -52,12 +52,13 @@ void Relocation::pd_set_data_value(address x, intptr_t o, bool verify_only) {
address disp = Assembler::locate_operand(addr(), which);
// both compressed oops and compressed classes look the same
if (CompressedOops::is_in((void*)x)) {
- if (verify_only) {
- guarantee(*(uint32_t*) disp == CompressedOops::encode((oop)x), "instructions must match");
+ uint32_t encoded = CompressedOops::narrow_oop_value((oop)x);
+ if (verify_only) {
+ guarantee(*(uint32_t*) disp == encoded, "instructions must match");
+ } else {
+ *(int32_t*) disp = encoded;
+ }
} else {
- *(int32_t*) disp = CompressedOops::encode((oop)x);
- }
- } else {
if (verify_only) {
guarantee(*(uint32_t*) disp == CompressedKlassPointers::encode((Klass*)x), "instructions must match");
} else {
diff --git a/src/hotspot/share/classfile/stringTable.cpp b/src/hotspot/share/classfile/stringTable.cpp
index ad74c462782c3..fbfd14c101131 100644
--- a/src/hotspot/share/classfile/stringTable.cpp
+++ b/src/hotspot/share/classfile/stringTable.cpp
@@ -67,7 +67,7 @@ const double CLEAN_DEAD_HIGH_WATER_MARK = 0.5;
#if INCLUDE_CDS_JAVA_HEAP
inline oop read_string_from_compact_hashtable(address base_address, u4 offset) {
assert(sizeof(narrowOop) == sizeof(offset), "must be");
- narrowOop v = (narrowOop)offset;
+ narrowOop v = CompressedOops::narrow_oop_cast(offset);
return HeapShared::decode_from_archive(v);
}
@@ -750,7 +750,7 @@ class CopyToArchive : StackObj {
}
// add to the compact table
- _writer->add(hash, CompressedOops::encode(new_s));
+ _writer->add(hash, CompressedOops::narrow_oop_value(new_s));
return true;
}
};
diff --git a/src/hotspot/share/gc/shared/locationPrinter.inline.hpp b/src/hotspot/share/gc/shared/locationPrinter.inline.hpp
index 9ac0ee1acfec0..343687ae0f0a6 100644
--- a/src/hotspot/share/gc/shared/locationPrinter.inline.hpp
+++ b/src/hotspot/share/gc/shared/locationPrinter.inline.hpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2020, 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
@@ -70,11 +70,12 @@ bool BlockLocationPrinter<CollectedHeapT>::print_location(outputStream* st, void
// Compressed oop needs to be decoded first.
#ifdef _LP64
if (UseCompressedOops && ((uintptr_t)addr &~ (uintptr_t)max_juint) == 0) {
- narrowOop narrow_oop = (narrowOop)(uintptr_t)addr;
+ narrowOop narrow_oop = CompressedOops::narrow_oop_cast((uintptr_t)addr);
oop o = CompressedOops::decode_raw(narrow_oop);
if (is_valid_obj(o)) {
- st->print(UINT32_FORMAT " is a compressed pointer to object: ", narrow_oop);
+ st->print(UINT32_FORMAT " is a compressed pointer to object: ",
+ CompressedOops::narrow_oop_value(narrow_oop));
o->print_on(st);
return true;
}
diff --git a/src/hotspot/share/gc/shared/referenceProcessor.hpp b/src/hotspot/share/gc/shared/referenceProcessor.hpp
index 83fc5bafee7c0..74eeafcd1adb0 100644
--- a/src/hotspot/share/gc/shared/referenceProcessor.hpp
+++ b/src/hotspot/share/gc/shared/referenceProcessor.hpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2020, 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
@@ -39,7 +39,7 @@ class ReferenceProcessorPhaseTimes;
// List of discovered references.
class DiscoveredList {
public:
- DiscoveredList() : _oop_head(NULL), _compressed_head(0), _len(0) { }
+ DiscoveredList() : _oop_head(NULL), _compressed_head(narrowOop::null), _len(0) { }
inline oop head() const;
HeapWord* adr_head() {
return UseCompressedOops ? (HeapWord*)&_compressed_head :
diff --git a/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp b/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp
index e207a27daf9f0..3bb97e01f593d 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeap.inline.hpp
@@ -149,14 +149,14 @@ inline oop ShenandoahHeap::cas_oop(oop n, oop* addr, oop c) {
inline oop ShenandoahHeap::cas_oop(oop n, narrowOop* addr, narrowOop c) {
assert(is_aligned(addr, sizeof(narrowOop)), "Address should be aligned: " PTR_FORMAT, p2i(addr));
narrowOop val = CompressedOops::encode(n);
- return CompressedOops::decode((narrowOop) Atomic::cmpxchg(addr, c, val));
+ return CompressedOops::decode(Atomic::cmpxchg(addr, c, val));
}
inline oop ShenandoahHeap::cas_oop(oop n, narrowOop* addr, oop c) {
assert(is_aligned(addr, sizeof(narrowOop)), "Address should be aligned: " PTR_FORMAT, p2i(addr));
narrowOop cmp = CompressedOops::encode(c);
narrowOop val = CompressedOops::encode(n);
- return CompressedOops::decode((narrowOop) Atomic::cmpxchg(addr, cmp, val));
+ return CompressedOops::decode(Atomic::cmpxchg(addr, cmp, val));
}
template <class T>
diff --git a/src/hotspot/share/jfr/leakprofiler/chains/rootSetClosure.cpp b/src/hotspot/share/jfr/leakprofiler/chains/rootSetClosure.cpp
index 17e621580630b..73a76cf07df52 100644
--- a/src/hotspot/share/jfr/leakprofiler/chains/rootSetClosure.cpp
+++ b/src/hotspot/share/jfr/leakprofiler/chains/rootSetClosure.cpp
@@ -57,7 +57,7 @@ template <typename Delegate>
void RootSetClosure<Delegate>::do_oop(narrowOop* ref) {
assert(ref != NULL, "invariant");
assert(is_aligned(ref, sizeof(narrowOop)), "invariant");
- if (*ref != 0) {
+ if (CompressedOops::is_null(*ref)) {
_delegate->do_root(UnifiedOopRef::encode_in_native(ref));
}
}
diff --git a/src/hotspot/share/memory/archiveUtils.cpp b/src/hotspot/share/memory/archiveUtils.cpp
index cb8982b279bf4..2b5ae7309f674 100644
--- a/src/hotspot/share/memory/archiveUtils.cpp
+++ b/src/hotspot/share/memory/archiveUtils.cpp
@@ -271,8 +271,8 @@ void ReadClosure::do_tag(int tag) {
}
void ReadClosure::do_oop(oop *p) {
- narrowOop o = (narrowOop)nextPtr();
- if (o == 0 || !HeapShared::open_archive_heap_region_mapped()) {
+ narrowOop o = CompressedOops::narrow_oop_cast(nextPtr());
+ if (CompressedOops::is_null(o) || !HeapShared::open_archive_heap_region_mapped()) {
*p = NULL;
} else {
assert(HeapShared::is_heap_object_archiving_allowed(),
diff --git a/src/hotspot/share/memory/filemap.cpp b/src/hotspot/share/memory/filemap.cpp
index 5137b823d6b0e..f61875e7d91bc 100644
--- a/src/hotspot/share/memory/filemap.cpp
+++ b/src/hotspot/share/memory/filemap.cpp
@@ -1663,8 +1663,7 @@ size_t FileMapInfo::read_bytes(void* buffer, size_t count) {
address FileMapInfo::decode_start_address(FileMapRegion* spc, bool with_current_oop_encoding_mode) {
size_t offset = spc->mapping_offset();
- assert(offset == (size_t)(uint32_t)offset, "must be 32-bit only");
- uint n = (uint)offset;
+ narrowOop n = CompressedOops::narrow_oop_cast(offset);
if (with_current_oop_encoding_mode) {
return cast_from_oop<address>(CompressedOops::decode_not_null(n));
} else {
diff --git a/src/hotspot/share/memory/heapShared.cpp b/src/hotspot/share/memory/heapShared.cpp
index b84c8033af4c2..1d9821300f446 100644
--- a/src/hotspot/share/memory/heapShared.cpp
+++ b/src/hotspot/share/memory/heapShared.cpp
@@ -383,7 +383,7 @@ void KlassSubGraphInfo::add_subgraph_entry_field(
new(ResourceObj::C_HEAP, mtClass) GrowableArray<juint>(10, mtClass);
}
_subgraph_entry_fields->append((juint)static_field_offset);
- _subgraph_entry_fields->append(CompressedOops::encode(v));
+ _subgraph_entry_fields->append(CompressedOops::narrow_oop_value(v));
_subgraph_entry_fields->append(is_closed_archive ? 1 : 0);
}
@@ -591,7 +591,7 @@ void HeapShared::initialize_from_archived_subgraph(Klass* k, TRAPS) {
assert(efr_len % 3 == 0, "sanity");
for (i = 0; i < efr_len;) {
int field_offset = entry_field_records->at(i);
- narrowOop nv = entry_field_records->at(i+1);
+ narrowOop nv = CompressedOops::narrow_oop_cast(entry_field_records->at(i+1));
int is_closed_archive = entry_field_records->at(i+2);
oop v;
if (is_closed_archive == 0) {
diff --git a/src/hotspot/share/oops/compressedOops.hpp b/src/hotspot/share/oops/compressedOops.hpp
index 3522606b45733..60f099c9be932 100644
--- a/src/hotspot/share/oops/compressedOops.hpp
+++ b/src/hotspot/share/oops/compressedOops.hpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2020, 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
@@ -29,6 +29,7 @@
#include "memory/memRegion.hpp"
#include "oops/oopsHierarchy.hpp"
#include "utilities/globalDefinitions.hpp"
+#include <type_traits>
class outputStream;
class ReservedHeapSpace;
@@ -76,6 +77,10 @@ class CompressedOops : public AllStatic {
AnyNarrowOopMode = 4
};
+ // The representation type for narrowOop is assumed to be uint32_t.
+ static_assert(std::is_same<uint32_t, std::underlying_type_t<narrowOop>>::value,
+ "narrowOop has unexpected representation type");
+
static void initialize(const ReservedHeapSpace& heap_space);
static void set_base(address base);
@@ -112,7 +117,7 @@ class CompressedOops : public AllStatic {
static void print_mode(outputStream* st);
static bool is_null(oop v) { return v == NULL; }
- static bool is_null(narrowOop v) { return v == 0; }
+ static bool is_null(narrowOop v) { return v == narrowOop::null; }
static inline oop decode_raw(narrowOop v);
static inline oop decode_not_null(narrowOop v);
@@ -125,6 +130,12 @@ class CompressedOops : public AllStatic {
static oop decode(oop v) { return v; }
static narrowOop encode_not_null(narrowOop v) { return v; }
static narrowOop encode(narrowOop v) { return v; }
+
+ static inline uint32_t narrow_oop_value(oop o);
+ static inline uint32_t narrow_oop_value(narrowOop o);
+
+ template<typename T>
+ static inline narrowOop narrow_oop_cast(T i);
};
// For UseCompressedClassPointers.
diff --git a/src/hotspot/share/oops/compressedOops.inline.hpp b/src/hotspot/share/oops/compressedOops.inline.hpp
index 3fcaa2f54c600..8c8a922094dc2 100644
--- a/src/hotspot/share/oops/compressedOops.inline.hpp
+++ b/src/hotspot/share/oops/compressedOops.inline.hpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2020, 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
@@ -62,14 +62,30 @@ inline narrowOop CompressedOops::encode_not_null(oop v) {
assert(is_in(v), "address not in heap range: " PTR_FORMAT, p2i((void*)v));
uint64_t pd = (uint64_t)(pointer_delta((void*)v, (void*)base(), 1));
assert(OopEncodingHeapMax > pd, "change encoding max if new encoding");
- uint64_t result = pd >> shift();
- assert((result & CONST64(0xffffffff00000000)) == 0, "narrow oop overflow");
+ narrowOop result = narrow_oop_cast(pd >> shift());
assert(decode(result) == v, "reversibility");
- return (narrowOop)result;
+ return result;
}
inline narrowOop CompressedOops::encode(oop v) {
- return is_null(v) ? (narrowOop)0 : encode_not_null(v);
+ return is_null(v) ? narrowOop::null : encode_not_null(v);
+}
+
+inline uint32_t CompressedOops::narrow_oop_value(oop o) {
+ return narrow_oop_value(encode(o));
+}
+
+inline uint32_t CompressedOops::narrow_oop_value(narrowOop o) {
+ return static_cast<uint32_t>(o);
+}
+
+template<typename T>
+inline narrowOop CompressedOops::narrow_oop_cast(T i) {
+ static_assert(std::is_integral<T>::value, "precondition");
+ uint32_t narrow_value = static_cast<uint32_t>(i);
+ // Ensure no bits lost in conversion to uint32_t.
+ assert(i == static_cast<T>(narrow_value), "narrowOop overflow");
+ return static_cast<narrowOop>(narrow_value);
}
static inline bool check_alignment(Klass* v) {
diff --git a/src/hotspot/share/oops/cpCache.inline.hpp b/src/hotspot/share/oops/cpCache.inline.hpp
index 46069d7c63732..b32cde7de0d09 100644
--- a/src/hotspot/share/oops/cpCache.inline.hpp
+++ b/src/hotspot/share/oops/cpCache.inline.hpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2020, 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
@@ -89,7 +89,7 @@ inline ConstantPoolCache::ConstantPoolCache(int length,
const intStack& invokedynamic_references_map) :
_length(length),
_constant_pool(NULL) {
- CDS_JAVA_HEAP_ONLY(_archived_references = 0;)
+ CDS_JAVA_HEAP_ONLY(_archived_references = narrowOop::null;)
initialize(inverse_index_map, invokedynamic_inverse_index_map,
invokedynamic_references_map);
for (int i = 0; i < length; i++) {
diff --git a/src/hotspot/share/oops/klass.cpp b/src/hotspot/share/oops/klass.cpp
index c0491e29d492c..16f02330f661a 100644
--- a/src/hotspot/share/oops/klass.cpp
+++ b/src/hotspot/share/oops/klass.cpp
@@ -204,7 +204,7 @@ Klass::Klass(KlassID id) : _id(id),
_prototype_header(markWord::prototype()),
_shared_class_path_index(-1) {
CDS_ONLY(_shared_class_flags = 0;)
- CDS_JAVA_HEAP_ONLY(_archived_mirror = 0;)
+ CDS_JAVA_HEAP_ONLY(_archived_mirror = narrowOop::null;)
_primary_supers[0] = this;
set_super_check_offset(in_bytes(primary_supers_offset()));
}
diff --git a/src/hotspot/share/oops/klass.hpp b/src/hotspot/share/oops/klass.hpp
index 2904dbf0c510f..97fc6cacd645c 100644
--- a/src/hotspot/share/oops/klass.hpp
+++ b/src/hotspot/share/oops/klass.hpp
@@ -263,7 +263,7 @@ class Klass : public Metadata {
void set_java_mirror(Handle m);
oop archived_java_mirror_raw() NOT_CDS_JAVA_HEAP_RETURN_(NULL); // no GC barrier
- narrowOop archived_java_mirror_raw_narrow() NOT_CDS_JAVA_HEAP_RETURN_(0); // no GC barrier
+ narrowOop archived_java_mirror_raw_narrow() NOT_CDS_JAVA_HEAP_RETURN_(narrowOop::null); // no GC barrier
void set_archived_java_mirror_raw(oop m) NOT_CDS_JAVA_HEAP_RETURN; // no GC barrier
// Temporary mirror switch used by RedefineClasses
diff --git a/src/hotspot/share/oops/oop.cpp b/src/hotspot/share/oops/oop.cpp
index c7e1a02de8a8a..bbea8fd4cd627 100644
--- a/src/hotspot/share/oops/oop.cpp
+++ b/src/hotspot/share/oops/oop.cpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2020, 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
@@ -157,7 +157,7 @@ void* oopDesc::load_oop_raw(oop obj, int offset) {
uintptr_t addr = (uintptr_t)(void*)obj + (uint)offset;
if (UseCompressedOops) {
narrowOop narrow_oop = *(narrowOop*)addr;
- if (narrow_oop == 0) return NULL;
+ if (CompressedOops::is_null(narrow_oop)) return NULL;
return (void*)CompressedOops::decode_raw(narrow_oop);
} else {
return *(void**)addr;
diff --git a/src/hotspot/share/oops/oopsHierarchy.hpp b/src/hotspot/share/oops/oopsHierarchy.hpp
index ac5b91bc94b2c..1ba3b470f0689 100644
--- a/src/hotspot/share/oops/oopsHierarchy.hpp
+++ b/src/hotspot/share/oops/oopsHierarchy.hpp
@@ -33,7 +33,8 @@
// This hierarchy is a representation hierarchy, i.e. if A is a superclass
// of B, A's representation is a prefix of B's representation.
-typedef juint narrowOop; // Offset instead of address for an oop within a java object
+// Global offset instead of address for an oop within a java object.
+enum class narrowOop : uint32_t { null = 0 };
// If compressed klass pointers then use narrowKlass.
typedef juint narrowKlass;
diff --git a/src/hotspot/share/runtime/stackValue.cpp b/src/hotspot/share/runtime/stackValue.cpp
index 2757e5e67d494..ac8b3a6561b66 100644
--- a/src/hotspot/share/runtime/stackValue.cpp
+++ b/src/hotspot/share/runtime/stackValue.cpp
@@ -98,8 +98,12 @@ StackValue* StackValue::create_stack_value(const frame* fr, const RegisterMap* r
// The callee has no clue whether the register holds an int,
// long or is unused. He always saves a long. Here we know
// a long was saved, but we only want an int back. Narrow the
- // saved long to the int that the JVM wants.
- value.noop = (narrowOop) *(julong*) value_addr;
+ // saved long to the int that the JVM wants. We can't just
+ // use narrow_oop_cast directly, because we don't know what
+ // the high bits of the value might be.
+ static_assert(sizeof(narrowOop) == sizeof(juint), "size mismatch");
+ juint narrow_value = (juint) *(julong*)value_addr;
+ value.noop = CompressedOops::narrow_oop_cast(narrow_value);
} else {
value.noop = *(narrowOop*) value_addr;
}