42 // Making the klass's CLD handle oops (e.g. the java_mirror), safe to store in the object
43 // graph and its roots (e.g. Handles).
44 static_cast<void>(klass_holder());
45 }
46
47 inline bool Klass::is_non_strong_hidden() const {
48 return is_hidden() && class_loader_data()->has_class_mirror_holder();
49 }
50
51 // Iff the class loader (or mirror for non-strong hidden classes) is alive the
52 // Klass is considered alive. This is safe to call before the CLD is marked as
53 // unloading, and hence during concurrent class unloading.
54 // This returns false if the Klass is unloaded, or about to be unloaded because the holder of
55 // the CLD is no longer strongly reachable.
56 // The return value of this function may change from true to false after a safepoint. So the caller
57 // of this function must ensure that a safepoint doesn't happen while interpreting the return value.
58 inline bool Klass::is_loader_alive() const {
59 return class_loader_data()->is_alive();
60 }
61
62 inline bool Klass::is_loader_present_and_alive() const {
63 ClassLoaderData* cld = class_loader_data();
64 return (cld != nullptr) ? cld->is_alive() : false;
65 }
66
67 inline markWord Klass::prototype_header() const {
68 assert(UseCompactObjectHeaders, "only use with compact object headers");
69 #ifdef _LP64
70 // You only need prototypes for allocating objects. If the class is not instantiable, it won't live in
71 // class space and have no narrow Klass ID. But in that case we should not need the prototype.
72 assert(_prototype_header.narrow_klass() > 0, "Klass " PTR_FORMAT ": invalid prototype (" PTR_FORMAT ")",
73 p2i(this), _prototype_header.value());
74 #endif
75 return _prototype_header;
76 }
77
78 // This is only used when dumping the archive. In other cases,
79 // the _prototype_header is already initialized to the right thing.
80 inline void Klass::set_prototype_header(markWord header) {
81 assert(UseCompactObjectHeaders, "only with compact headers");
82 _prototype_header = header;
83 }
84
85 // Loading the java_mirror does not keep its holder alive. See Klass::keep_alive().
86 inline oop Klass::java_mirror() const {
87 return _java_mirror.resolve();
88 }
89
90 inline oop Klass::java_mirror_no_keepalive() const {
91 return _java_mirror.peek();
92 }
93
94 inline klassVtable Klass::vtable() const {
95 return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
96 }
97
98 inline oop Klass::class_loader() const {
99 return class_loader_data()->class_loader();
100 }
101
102 inline vtableEntry* Klass::start_of_vtable() const {
103 return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
104 }
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42 // Making the klass's CLD handle oops (e.g. the java_mirror), safe to store in the object
43 // graph and its roots (e.g. Handles).
44 static_cast<void>(klass_holder());
45 }
46
47 inline bool Klass::is_non_strong_hidden() const {
48 return is_hidden() && class_loader_data()->has_class_mirror_holder();
49 }
50
51 // Iff the class loader (or mirror for non-strong hidden classes) is alive the
52 // Klass is considered alive. This is safe to call before the CLD is marked as
53 // unloading, and hence during concurrent class unloading.
54 // This returns false if the Klass is unloaded, or about to be unloaded because the holder of
55 // the CLD is no longer strongly reachable.
56 // The return value of this function may change from true to false after a safepoint. So the caller
57 // of this function must ensure that a safepoint doesn't happen while interpreting the return value.
58 inline bool Klass::is_loader_alive() const {
59 return class_loader_data()->is_alive();
60 }
61
62 inline markWord Klass::make_prototype_header(const Klass* kls, markWord prototype) {
63 if (UseCompactObjectHeaders) {
64 // With compact object headers, the narrow Klass ID is part of the mark word.
65 // We therefore seed the mark word with the narrow Klass ID.
66 // Note that only those Klass that can be instantiated have a narrow Klass ID.
67 // For those who don't, we leave the klass bits empty and assert if someone
68 // tries to use those.
69 const narrowKlass nk = CompressedKlassPointers::is_encodable(kls) ?
70 CompressedKlassPointers::encode(const_cast<Klass*>(kls)) : 0;
71 prototype = prototype.set_narrow_klass(nk);
72 }
73 return prototype;
74 }
75
76 inline void Klass::set_prototype_header(markWord header) {
77 _prototype_header = header;
78 }
79
80 inline bool Klass::is_loader_present_and_alive() const {
81 ClassLoaderData* cld = class_loader_data();
82 return (cld != nullptr) ? cld->is_alive() : false;
83 }
84
85 inline markWord Klass::prototype_header() const {
86 // You only need prototypes for allocating objects. If the class is not instantiable, it won't live in
87 // class space and have no narrow Klass ID. But in that case we should not need the prototype.
88 assert(!UseCompactObjectHeaders || _prototype_header.narrow_klass() > 0, "Klass " PTR_FORMAT ": invalid prototype (" PTR_FORMAT ")",
89 p2i(this), _prototype_header.value());
90 return _prototype_header;
91 }
92
93 // May no longer be required (was used to avoid a bootstrapping problem...
94 inline markWord Klass::default_prototype_header(Klass* k) {
95 return (k == nullptr) ? markWord::prototype() : k->prototype_header();
96 }
97
98
99 // Loading the java_mirror does not keep its holder alive. See Klass::keep_alive().
100 inline oop Klass::java_mirror() const {
101 return _java_mirror.resolve();
102 }
103
104 inline oop Klass::java_mirror_no_keepalive() const {
105 return _java_mirror.peek();
106 }
107
108 inline klassVtable Klass::vtable() const {
109 return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
110 }
111
112 inline oop Klass::class_loader() const {
113 return class_loader_data()->class_loader();
114 }
115
116 inline vtableEntry* Klass::start_of_vtable() const {
117 return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
118 }
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