1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25 #ifndef SHARE_OOPS_KLASSVTABLE_HPP
26 #define SHARE_OOPS_KLASSVTABLE_HPP
27
28 #include "oops/oopsHierarchy.hpp"
29 #include "runtime/handles.hpp"
30 #include "utilities/growableArray.hpp"
31
32 // A klassVtable abstracts the variable-length vtable that is embedded in InstanceKlass
33 // and ArrayKlass. klassVtable objects are used just as convenient transient accessors to the vtable,
34 // not to actually hold the vtable data.
35 // Note: the klassVtable should not be accessed before the class has been verified
36 // (until that point, the vtable is uninitialized).
37
38 // Currently a klassVtable contains a direct reference to the vtable data, and is therefore
39 // not preserved across GCs.
40
41 class vtableEntry;
42
43 class klassVtable {
44 Klass* _klass; // my klass
45 int _tableOffset; // offset of start of vtable data within klass
46 int _length; // length of vtable (number of entries)
47 #ifndef PRODUCT
48 int _verify_count; // to make verify faster
49 #endif
50
51 public:
52 klassVtable(Klass* klass, void* base, int length) : _klass(klass) {
53 _tableOffset = (address)base - (address)klass; _length = length;
54 }
55
56 // accessors
57 vtableEntry* table() const { return (vtableEntry*)(address(_klass) + _tableOffset); }
58 Klass* klass() const { return _klass; }
59 int length() const { return _length; }
60 inline Method* method_at(int i) const;
61 inline Method* unchecked_method_at(int i) const;
62
63 // searching; all methods return -1 if not found
64 int index_of_miranda(Symbol* name, Symbol* signature);
65
66 void initialize_vtable(bool checkconstraints, TRAPS); // initialize vtable of a new klass
67
68 // computes vtable length (in words) and the number of miranda methods
69 static void compute_vtable_size_and_num_mirandas(int* vtable_length,
70 int* num_new_mirandas,
71 GrowableArray<Method*>* all_mirandas,
72 const Klass* super,
73 Array<Method*>* methods,
74 AccessFlags class_flags,
75 u2 major_version,
76 Handle classloader,
77 Symbol* classname,
78 Array<InstanceKlass*>* local_interfaces,
79 TRAPS);
80
81 #if INCLUDE_JVMTI
82 // RedefineClasses() API support:
83 // If any entry of this vtable points to any of old_methods,
84 // replace it with the corresponding new_method.
85 // trace_name_printed is set to true if the current call has
86 // printed the klass name so that other routines in the adjust_*
87 // group don't print the klass name.
88 bool adjust_default_method(int vtable_index, Method* old_method, Method* new_method);
89 void adjust_method_entries(bool* trace_name_printed);
90 bool check_no_old_or_obsolete_entries();
91 void dump_vtable();
92 #endif // INCLUDE_JVMTI
93
94 // Debugging code
95 void print() PRODUCT_RETURN;
96 void verify(outputStream* st, bool force = false);
97 static void print_statistics() PRODUCT_RETURN;
98
99 protected:
100 friend class vtableEntry;
101
102 public:
103 // Transitive overridng rules for class files < JDK1_7 use the older JVMS rules.
104 // Overriding is determined as we create the vtable, so we use the class file version
105 // of the class whose vtable we are calculating.
106 enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;
107
108 private:
109 void copy_vtable_to(vtableEntry* start);
110 int initialize_from_super(Klass* super);
111 void put_method_at(Method* m, int index);
112 static bool needs_new_vtable_entry(const methodHandle& m,
113 const Klass* super,
114 Handle classloader,
115 Symbol* classname,
116 AccessFlags access_flags,
117 u2 major_version,
118 TRAPS);
119
120 bool update_inherited_vtable(InstanceKlass* klass, const methodHandle& target_method, int super_vtable_len, int default_index, bool checkconstraints, TRAPS);
121 InstanceKlass* find_transitive_override(InstanceKlass* initialsuper, const methodHandle& target_method, int vtable_index,
122 Handle target_loader, Symbol* target_classname, Thread* THREAD);
123
124 // support for miranda methods
125 bool is_miranda_entry_at(int i);
126 int fill_in_mirandas(int initialized, TRAPS);
127 static bool is_miranda(Method* m, Array<Method*>* class_methods,
128 Array<Method*>* default_methods, const Klass* super,
129 bool is_interface);
130 static void add_new_mirandas_to_lists(
131 GrowableArray<Method*>* new_mirandas,
132 GrowableArray<Method*>* all_mirandas,
133 Array<Method*>* current_interface_methods,
134 Array<Method*>* class_methods,
135 Array<Method*>* default_methods,
136 const Klass* super,
137 bool is_interface);
138 static void get_mirandas(
139 GrowableArray<Method*>* new_mirandas,
140 GrowableArray<Method*>* all_mirandas,
141 const Klass* super,
142 Array<Method*>* class_methods,
143 Array<Method*>* default_methods,
144 Array<InstanceKlass*>* local_interfaces,
145 bool is_interface);
146 void verify_against(outputStream* st, klassVtable* vt, int index);
147 inline InstanceKlass* ik() const;
148 // When loading a class from CDS archive at run time, and no class redefintion
149 // has happened, it is expected that the class's itable/vtables are
150 // laid out exactly the same way as they had been during dump time.
151 // Therefore, in klassVtable::initialize_[iv]table, we do not layout the
152 // tables again. Instead, we only rerun the process to create/check
153 // the class loader constraints. In non-product builds, we add asserts to
154 // guarantee that the table's layout would be the same as at dump time.
155 //
156 // If JVMTI redefines any class, the read-only shared memory are remapped
157 // as read-write. A shared class' vtable/itable are re-initialized and
158 // might have different layout due to class redefinition of the shared class
159 // or its super types.
160 bool is_preinitialized_vtable();
161 };
162
163
164 // private helper class for klassVtable
165 // description of entry points:
166 // destination is interpreted:
167 // from_compiled_code_entry_point -> c2iadapter
168 // from_interpreter_entry_point -> interpreter entry point
169 // destination is compiled:
170 // from_compiled_code_entry_point -> nmethod entry point
171 // from_interpreter_entry_point -> i2cadapter
172 class vtableEntry {
173 friend class VMStructs;
174 friend class JVMCIVMStructs;
175
176 public:
177 // size in words
178 static int size() { return sizeof(vtableEntry) / wordSize; }
179 static int size_in_bytes() { return sizeof(vtableEntry); }
180
181 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }
182 Method* method() const { return _method; }
183 Method** method_addr() { return &_method; }
184
185 private:
186 Method* _method;
187 void set(Method* method) { assert(method != NULL, "use clear"); _method = method; }
188 void clear() { _method = NULL; }
189 void print() PRODUCT_RETURN;
190 void verify(klassVtable* vt, outputStream* st);
191
192 friend class klassVtable;
193 };
194
195
196 inline Method* klassVtable::method_at(int i) const {
197 assert(i >= 0 && i < _length, "index out of bounds");
198 assert(table()[i].method() != NULL, "should not be null");
199 assert(((Metadata*)table()[i].method())->is_method(), "should be method");
200 return table()[i].method();
201 }
202
203 inline Method* klassVtable::unchecked_method_at(int i) const {
204 assert(i >= 0 && i < _length, "index out of bounds");
205 return table()[i].method();
206 }
207
208 // --------------------------------------------------------------------------------
209 class klassItable;
210 class itableMethodEntry;
211
212 class itableOffsetEntry {
213 private:
214 InstanceKlass* _interface;
215 int _offset;
216 public:
217 InstanceKlass* interface_klass() const { return _interface; }
218 InstanceKlass**interface_klass_addr() { return &_interface; }
219 int offset() const { return _offset; }
220
221 static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }
222 itableMethodEntry* first_method_entry(Klass* k) { return method_entry(k, _offset); }
223
224 void initialize(InstanceKlass* interf, int offset) { _interface = interf; _offset = offset; }
225
226 // Static size and offset accessors
227 static int size() { return sizeof(itableOffsetEntry) / wordSize; } // size in words
228 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); }
229 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); }
230
231 friend class klassItable;
232 };
233
234
235 class itableMethodEntry {
236 private:
237 Method* _method;
238
239 public:
240 Method* method() const { return _method; }
241 Method**method_addr() { return &_method; }
242
243 void clear() { _method = NULL; }
244
245 void initialize(Method* method);
246
247 // Static size and offset accessors
248 static int size() { return sizeof(itableMethodEntry) / wordSize; } // size in words
249 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); }
250
251 friend class klassItable;
252 };
253
254 //
255 // Format of an itable
256 //
257 // ---- offset table ---
258 // Klass* of interface 1 \
259 // offset to vtable from start of oop / offset table entry
260 // ...
261 // Klass* of interface n \
262 // offset to vtable from start of oop / offset table entry
263 // --- vtable for interface 1 ---
264 // Method* \
265 // compiler entry point / method table entry
266 // ...
267 // Method* \
268 // compiler entry point / method table entry
269 // -- vtable for interface 2 ---
270 // ...
271 //
272 class klassItable {
273 private:
274 InstanceKlass* _klass; // my klass
275 int _table_offset; // offset of start of itable data within klass (in words)
276 int _size_offset_table; // size of offset table (in itableOffset entries)
277 int _size_method_table; // size of methodtable (in itableMethodEntry entries)
278
279 void initialize_itable_for_interface(int method_table_offset, InstanceKlass* interf_h, bool checkconstraints, TRAPS);
280 public:
281 klassItable(InstanceKlass* klass);
282
283 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");
284 return &((itableOffsetEntry*)vtable_start())[i]; }
285
286 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");
287 return &((itableMethodEntry*)method_start())[i]; }
288
289 int size_offset_table() { return _size_offset_table; }
290
291 // Initialization
292 void initialize_itable(bool checkconstraints, TRAPS);
293
294 #if INCLUDE_JVMTI
295 // RedefineClasses() API support:
296 // if any entry of this itable points to any of old_methods,
297 // replace it with the corresponding new_method.
298 // trace_name_printed is set to true if the current call has
299 // printed the klass name so that other routines in the adjust_*
300 // group don't print the klass name.
301 void adjust_method_entries(bool* trace_name_printed);
302 bool check_no_old_or_obsolete_entries();
303 void dump_itable();
304 #endif // INCLUDE_JVMTI
305
306 // Setup of itable
307 static int assign_itable_indices_for_interface(InstanceKlass* klass, TRAPS);
308 static int method_count_for_interface(InstanceKlass* klass);
309 static int compute_itable_size(Array<InstanceKlass*>* transitive_interfaces);
310 static void setup_itable_offset_table(InstanceKlass* klass);
311
312 // Debugging/Statistics
313 static void print_statistics() PRODUCT_RETURN;
314 private:
315 intptr_t* vtable_start() const { return ((intptr_t*)_klass) + _table_offset; }
316 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }
317
318 // Helper methods
319 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }
320
321 // Statistics
322 NOT_PRODUCT(static int _total_classes;) // Total no. of classes with itables
323 NOT_PRODUCT(static long _total_size;) // Total no. of bytes used for itables
324
325 static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; })
326 };
327
328 #endif // SHARE_OOPS_KLASSVTABLE_HPP