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 void check_constraints(GrowableArray<InstanceKlass*>* supers, TRAPS);
52
53 public:
54 klassVtable(Klass* klass, void* base, int length) : _klass(klass) {
55 _tableOffset = (address)base - (address)klass; _length = length;
56 }
57
58 // accessors
59 vtableEntry* table() const { return (vtableEntry*)(address(_klass) + _tableOffset); }
60 Klass* klass() const { return _klass; }
61 int length() const { return _length; }
62 inline Method* method_at(int i) const;
63 inline Method* unchecked_method_at(int i) const;
64
65 // searching; all methods return -1 if not found
66 int index_of_miranda(Symbol* name, Symbol* signature);
67
68 // initialize vtable of a new klass
69 void initialize_vtable(GrowableArray<InstanceKlass*>* supers = NULL);
70 void initialize_vtable_and_check_constraints(TRAPS);
71
72 // computes vtable length (in words) and the number of miranda methods
73 static void compute_vtable_size_and_num_mirandas(int* vtable_length,
74 int* num_new_mirandas,
75 GrowableArray<Method*>* all_mirandas,
76 const Klass* super,
77 Array<Method*>* methods,
78 AccessFlags class_flags,
79 u2 major_version,
80 Handle classloader,
81 Symbol* classname,
82 Array<InstanceKlass*>* local_interfaces);
83
84 #if INCLUDE_JVMTI
85 // RedefineClasses() API support:
86 // If any entry of this vtable points to any of old_methods,
87 // replace it with the corresponding new_method.
88 // trace_name_printed is set to true if the current call has
89 // printed the klass name so that other routines in the adjust_*
90 // group don't print the klass name.
91 bool adjust_default_method(int vtable_index, Method* old_method, Method* new_method);
92 void adjust_method_entries(bool* trace_name_printed);
93 bool check_no_old_or_obsolete_entries();
94 void dump_vtable();
95 #endif // INCLUDE_JVMTI
96
97 // Debugging code
98 void print() PRODUCT_RETURN;
99 void verify(outputStream* st, bool force = false);
100
101 protected:
102 friend class vtableEntry;
103
104 public:
105 // Transitive overridng rules for class files < JDK1_7 use the older JVMS rules.
106 // Overriding is determined as we create the vtable, so we use the class file version
107 // of the class whose vtable we are calculating.
108 enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;
109
110 private:
111 void copy_vtable_to(vtableEntry* start);
112 int initialize_from_super(Klass* super);
113 void put_method_at(Method* m, int index);
114 static bool needs_new_vtable_entry(Method* m,
115 const Klass* super,
116 Handle classloader,
117 Symbol* classname,
118 AccessFlags access_flags,
119 u2 major_version);
120
121 bool update_inherited_vtable(Thread* current,
122 const methodHandle& target_method,
123 int super_vtable_len,
124 int default_index,
125 GrowableArray<InstanceKlass*>* supers);
126 InstanceKlass* find_transitive_override(InstanceKlass* initialsuper,
127 const methodHandle& target_method, int vtable_index,
128 Handle target_loader, Symbol* target_classname);
129
130 // support for miranda methods
131 bool is_miranda_entry_at(int i);
132 int fill_in_mirandas(Thread* current, int initialized);
133 static bool is_miranda(Method* m, Array<Method*>* class_methods,
134 Array<Method*>* default_methods, const Klass* super,
135 bool is_interface);
136 static void add_new_mirandas_to_lists(
137 GrowableArray<Method*>* new_mirandas,
138 GrowableArray<Method*>* all_mirandas,
139 Array<Method*>* current_interface_methods,
140 Array<Method*>* class_methods,
141 Array<Method*>* default_methods,
142 const Klass* super,
143 bool is_interface);
144 static void get_mirandas(
145 GrowableArray<Method*>* new_mirandas,
146 GrowableArray<Method*>* all_mirandas,
147 const Klass* super,
148 Array<Method*>* class_methods,
149 Array<Method*>* default_methods,
150 Array<InstanceKlass*>* local_interfaces,
151 bool is_interface);
152 void verify_against(outputStream* st, klassVtable* vt, int index);
153 inline InstanceKlass* ik() const;
154 // When loading a class from CDS archive at run time, and no class redefinition
155 // has happened, it is expected that the class's itable/vtables are
156 // laid out exactly the same way as they had been during dump time.
157 // Therefore, in klassVtable::initialize_[iv]table, we do not layout the
158 // tables again. Instead, we only rerun the process to create/check
159 // the class loader constraints. In non-product builds, we add asserts to
160 // guarantee that the table's layout would be the same as at dump time.
161 //
162 // If JVMTI redefines any class, the read-only shared memory are remapped
163 // as read-write. A shared class' vtable/itable are re-initialized and
164 // might have different layout due to class redefinition of the shared class
165 // or its super types.
166 bool is_preinitialized_vtable();
167 };
168
169
170 // private helper class for klassVtable
171 // description of entry points:
172 // destination is interpreted:
173 // from_compiled_code_entry_point -> c2iadapter
174 // from_interpreter_entry_point -> interpreter entry point
175 // destination is compiled:
176 // from_compiled_code_entry_point -> nmethod entry point
177 // from_interpreter_entry_point -> i2cadapter
178 class vtableEntry {
179 friend class VMStructs;
180 friend class JVMCIVMStructs;
181
182 public:
183 // size in words
184 static int size() { return sizeof(vtableEntry) / wordSize; }
185 static int size_in_bytes() { return sizeof(vtableEntry); }
186
187 static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }
188 Method* method() const { return _method; }
189 Method** method_addr() { return &_method; }
190
191 private:
192 Method* _method;
193 void set(Method* method) { assert(method != NULL, "use clear"); _method = method; }
194 void clear() { _method = NULL; }
195 void print() PRODUCT_RETURN;
196 void verify(klassVtable* vt, outputStream* st);
197
198 friend class klassVtable;
199 };
200
201
202 inline Method* klassVtable::method_at(int i) const {
203 assert(i >= 0 && i < _length, "index out of bounds");
204 assert(table()[i].method() != NULL, "should not be null");
205 assert(((Metadata*)table()[i].method())->is_method(), "should be method");
206 return table()[i].method();
207 }
208
209 inline Method* klassVtable::unchecked_method_at(int i) const {
210 assert(i >= 0 && i < _length, "index out of bounds");
211 return table()[i].method();
212 }
213
214 // --------------------------------------------------------------------------------
215 class klassItable;
216 class itableMethodEntry;
217
218 class itableOffsetEntry {
219 private:
220 InstanceKlass* _interface;
221 int _offset;
222 public:
223 InstanceKlass* interface_klass() const { return _interface; }
224 InstanceKlass**interface_klass_addr() { return &_interface; }
225 int offset() const { return _offset; }
226
227 static itableMethodEntry* method_entry(Klass* k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }
228 itableMethodEntry* first_method_entry(Klass* k) { return method_entry(k, _offset); }
229
230 void initialize(InstanceKlass* interf, int offset) { _interface = interf; _offset = offset; }
231
232 // Static size and offset accessors
233 static int size() { return sizeof(itableOffsetEntry) / wordSize; } // size in words
234 static int interface_offset_in_bytes() { return offset_of(itableOffsetEntry, _interface); }
235 static int offset_offset_in_bytes() { return offset_of(itableOffsetEntry, _offset); }
236
237 friend class klassItable;
238 };
239
240
241 class itableMethodEntry {
242 private:
243 Method* _method;
244
245 public:
246 Method* method() const { return _method; }
247 Method**method_addr() { return &_method; }
248
249 void clear() { _method = NULL; }
250
251 void initialize(InstanceKlass* klass, Method* method);
252
253 // Static size and offset accessors
254 static int size() { return sizeof(itableMethodEntry) / wordSize; } // size in words
255 static int method_offset_in_bytes() { return offset_of(itableMethodEntry, _method); }
256
257 friend class klassItable;
258 };
259
260 //
261 // Format of an itable
262 //
263 // ---- offset table ---
264 // Klass* of interface 1 \
265 // offset to vtable from start of oop / offset table entry
266 // ...
267 // Klass* of interface n \
268 // offset to vtable from start of oop / offset table entry
269 // --- vtable for interface 1 ---
270 // Method* \
271 // compiler entry point / method table entry
272 // ...
273 // Method* \
274 // compiler entry point / method table entry
275 // -- vtable for interface 2 ---
276 // ...
277 //
278 class klassItable {
279 private:
280 InstanceKlass* _klass; // my klass
281 int _table_offset; // offset of start of itable data within klass (in words)
282 int _size_offset_table; // size of offset table (in itableOffset entries)
283 int _size_method_table; // size of methodtable (in itableMethodEntry entries)
284
285 void initialize_itable_for_interface(int method_table_offset, InstanceKlass* interf_h,
286 GrowableArray<Method*>* supers, int start_offset);
287 void check_constraints(GrowableArray<Method*>* supers, TRAPS);
288 public:
289 klassItable(InstanceKlass* klass);
290
291 itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");
292 return &((itableOffsetEntry*)vtable_start())[i]; }
293
294 itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");
295 return &((itableMethodEntry*)method_start())[i]; }
296
297 int size_offset_table() { return _size_offset_table; }
298
299 // Initialization
300 void initialize_itable_and_check_constraints(TRAPS);
301 void initialize_itable(GrowableArray<Method*>* supers = NULL);
302
303 #if INCLUDE_JVMTI
304 // RedefineClasses() API support:
305 // if any entry of this itable points to any of old_methods,
306 // replace it with the corresponding new_method.
307 // trace_name_printed is set to true if the current call has
308 // printed the klass name so that other routines in the adjust_*
309 // group don't print the klass name.
310 void adjust_method_entries(bool* trace_name_printed);
311 bool check_no_old_or_obsolete_entries();
312 void dump_itable();
313 #endif // INCLUDE_JVMTI
314
315 // Setup of itable
316 static int assign_itable_indices_for_interface(InstanceKlass* klass);
317 static int method_count_for_interface(InstanceKlass* klass);
318 static int compute_itable_size(Array<InstanceKlass*>* transitive_interfaces);
319 static void setup_itable_offset_table(InstanceKlass* klass);
320
321 private:
322 intptr_t* vtable_start() const { return ((intptr_t*)_klass) + _table_offset; }
323 intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }
324
325 // Helper methods
326 static int calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }
327
328 };
329
330 #endif // SHARE_OOPS_KLASSVTABLE_HPP