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_VM_OOPS_CPCACHEOOP_HPP
26 #define SHARE_VM_OOPS_CPCACHEOOP_HPP
27
28 #include "interpreter/bytecodes.hpp"
29 #include "memory/allocation.hpp"
30 #include "oops/arrayOop.hpp"
31 #include "utilities/array.hpp"
32
33 // A ConstantPoolCacheEntry describes an individual entry of the constant
34 // pool cache. There's 2 principal kinds of entries: field entries for in-
35 // stance & static field access, and method entries for invokes. Some of
36 // the entry layout is shared and looks as follows:
37 //
38 // bit number |31 0|
39 // bit length |-8--|-8--|---16----|
40 // --------------------------------
41 // _indices [ b2 | b1 | index ]
42 // _f1 [ entry specific ]
43 // _f2 [ entry specific ]
44 // _flags [t|f|vf|v|m|h|unused|field_index] (for field entries)
45 // bit length |4|1|1 |1|1|0|---7--|----16-----]
46 // _flags [t|f|vf|v|m|h|unused|eidx|psze] (for method entries)
47 // bit length |4|1|1 |1|1|1|---7--|-8--|-8--]
48
49 // --------------------------------
50 //
51 // with:
52 // index = original constant pool index
53 // b1 = bytecode 1
54 // b2 = bytecode 2
55 // psze = parameters size (method entries only)
56 // eidx = interpreter entry index (method entries only)
57 // field_index = index into field information in holder instanceKlass
58 // The index max is 0xffff (max number of fields in constant pool)
59 // and is multiplied by (instanceKlass::next_offset) when accessing.
60 // t = TosState (see below)
61 // f = field is marked final (see below)
62 // vf = virtual, final (method entries only : is_vfinal())
63 // v = field is volatile (see below)
64 // m = invokeinterface used for method in class Object (see below)
65 // h = RedefineClasses/Hotswap bit (see below)
66 //
67 // The flags after TosState have the following interpretation:
68 // bit 27: f flag true if field is marked final
69 // bit 26: vf flag true if virtual final method
70 // bit 25: v flag true if field is volatile (only for fields)
71 // bit 24: m flag true if invokeinterface used for method in class Object
72 // bit 23: 0 for fields, 1 for methods
73 //
74 // The flags 31, 30, 29, 28 together build a 4 bit number 0 to 8 with the
75 // following mapping to the TosState states:
76 //
77 // btos: 0
78 // ctos: 1
79 // stos: 2
80 // itos: 3
81 // ltos: 4
82 // ftos: 5
83 // dtos: 6
84 // atos: 7
85 // vtos: 8
86 //
87 // Entry specific: field entries:
88 // _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index
89 // _f1 = field holder
90 // _f2 = field offset in words
91 // _flags = field type information, original field index in field holder
92 // (field_index section)
93 //
94 // Entry specific: method entries:
95 // _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section),
96 // original constant pool index
97 // _f1 = method for all but virtual calls, unused by virtual calls
98 // (note: for interface calls, which are essentially virtual,
99 // contains klassOop for the corresponding interface.
100 // for invokedynamic, f1 contains the CallSite object for the invocation
101 // _f2 = method/vtable index for virtual calls only, unused by all other
102 // calls. The vf flag indicates this is a method pointer not an
103 // index.
104 // _flags = field type info (f section),
105 // virtual final entry (vf),
106 // interpreter entry index (eidx section),
107 // parameter size (psze section)
108 //
109 // Note: invokevirtual & invokespecial bytecodes can share the same constant
110 // pool entry and thus the same constant pool cache entry. All invoke
111 // bytecodes but invokevirtual use only _f1 and the corresponding b1
112 // bytecode, while invokevirtual uses only _f2 and the corresponding
113 // b2 bytecode. The value of _flags is shared for both types of entries.
114 //
115 // The fields are volatile so that they are stored in the order written in the
116 // source code. The _indices field with the bytecode must be written last.
117
118 class ConstantPoolCacheEntry VALUE_OBJ_CLASS_SPEC {
119 friend class VMStructs;
120 friend class constantPoolCacheKlass;
121 friend class constantPoolOopDesc; //resolve_constant_at_impl => set_f1
122
123 private:
124 volatile intx _indices; // constant pool index & rewrite bytecodes
125 volatile oop _f1; // entry specific oop field
126 volatile intx _f2; // entry specific int/oop field
127 volatile intx _flags; // flags
128
129
130 #ifdef ASSERT
131 bool same_methodOop(oop cur_f1, oop f1);
132 #endif
133
134 void set_bytecode_1(Bytecodes::Code code);
135 void set_bytecode_2(Bytecodes::Code code);
136 void set_f1(oop f1) {
137 oop existing_f1 = _f1; // read once
138 assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change");
139 oop_store(&_f1, f1);
140 }
141 void set_f2(intx f2) { assert(_f2 == 0 || _f2 == f2, "illegal field change"); _f2 = f2; }
142 int as_flags(TosState state, bool is_final, bool is_vfinal, bool is_volatile,
143 bool is_method_interface, bool is_method);
144 void set_flags(intx flags) { _flags = flags; }
145
146 public:
147 // specific bit values in flag field
148 // Note: the interpreter knows this layout!
149 enum FlagBitValues {
150 hotSwapBit = 23,
151 methodInterface = 24,
152 volatileField = 25,
153 vfinalMethod = 26,
154 finalField = 27
155 };
156
157 enum { field_index_mask = 0xFFFF };
158
159 // start of type bits in flags
160 // Note: the interpreter knows this layout!
161 enum FlagValues {
162 tosBits = 28
163 };
164
165 // Initialization
166 void initialize_entry(int original_index); // initialize primary entry
167 void initialize_secondary_entry(int main_index); // initialize secondary entry
168
169 void set_field( // sets entry to resolved field state
170 Bytecodes::Code get_code, // the bytecode used for reading the field
171 Bytecodes::Code put_code, // the bytecode used for writing the field
172 KlassHandle field_holder, // the object/klass holding the field
173 int orig_field_index, // the original field index in the field holder
174 int field_offset, // the field offset in words in the field holder
175 TosState field_type, // the (machine) field type
176 bool is_final, // the field is final
177 bool is_volatile // the field is volatile
178 );
179
180 void set_method( // sets entry to resolved method entry
181 Bytecodes::Code invoke_code, // the bytecode used for invoking the method
182 methodHandle method, // the method/prototype if any (NULL, otherwise)
183 int vtable_index // the vtable index if any, else negative
184 );
185
186 void set_interface_call(
187 methodHandle method, // Resolved method
188 int index // Method index into interface
189 );
190
191 void set_dynamic_call(
192 Handle call_site, // Resolved java.dyn.CallSite (f1)
193 methodHandle signature_invoker // determines signature information
194 );
195
196 // For JVM_CONSTANT_InvokeDynamic cache entries:
197 void initialize_bootstrap_method_index_in_cache(int bsm_cache_index);
198 int bootstrap_method_index_in_cache();
199
200 void set_parameter_size(int value) {
201 assert(parameter_size() == 0 || parameter_size() == value,
202 "size must not change");
203 // Setting the parameter size by itself is only safe if the
204 // current value of _flags is 0, otherwise another thread may have
205 // updated it and we don't want to overwrite that value. Don't
206 // bother trying to update it once it's nonzero but always make
207 // sure that the final parameter size agrees with what was passed.
208 if (_flags == 0) {
209 Atomic::cmpxchg_ptr((value & 0xFF), &_flags, 0);
210 }
211 guarantee(parameter_size() == value, "size must not change");
212 }
213
214 // Which bytecode number (1 or 2) in the index field is valid for this bytecode?
215 // Returns -1 if neither is valid.
216 static int bytecode_number(Bytecodes::Code code) {
217 switch (code) {
218 case Bytecodes::_getstatic : // fall through
219 case Bytecodes::_getfield : // fall through
220 case Bytecodes::_invokespecial : // fall through
221 case Bytecodes::_invokestatic : // fall through
222 case Bytecodes::_invokedynamic : // fall through
223 case Bytecodes::_invokeinterface : return 1;
224 case Bytecodes::_putstatic : // fall through
225 case Bytecodes::_putfield : // fall through
226 case Bytecodes::_invokevirtual : return 2;
227 default : break;
228 }
229 return -1;
230 }
231
232 // Has this bytecode been resolved? Only valid for invokes and get/put field/static.
233 bool is_resolved(Bytecodes::Code code) const {
234 switch (bytecode_number(code)) {
235 case 1: return (bytecode_1() == code);
236 case 2: return (bytecode_2() == code);
237 }
238 return false; // default: not resolved
239 }
240
241 // Accessors
242 bool is_secondary_entry() const { return (_indices & 0xFFFF) == 0; }
243 int constant_pool_index() const { assert((_indices & 0xFFFF) != 0, "must be main entry");
244 return (_indices & 0xFFFF); }
245 int main_entry_index() const { assert((_indices & 0xFFFF) == 0, "must be secondary entry");
246 return ((uintx)_indices >> 16); }
247 Bytecodes::Code bytecode_1() const { return Bytecodes::cast((_indices >> 16) & 0xFF); }
248 Bytecodes::Code bytecode_2() const { return Bytecodes::cast((_indices >> 24) & 0xFF); }
249 volatile oop f1() const { return _f1; }
250 bool is_f1_null() const { return (oop)_f1 == NULL; } // classifies a CPC entry as unbound
251 intx f2() const { return _f2; }
252 int field_index() const;
253 int parameter_size() const { return _flags & 0xFF; }
254 bool is_vfinal() const { return ((_flags & (1 << vfinalMethod)) == (1 << vfinalMethod)); }
255 bool is_volatile() const { return ((_flags & (1 << volatileField)) == (1 << volatileField)); }
256 bool is_methodInterface() const { return ((_flags & (1 << methodInterface)) == (1 << methodInterface)); }
257 bool is_byte() const { return (((uintx) _flags >> tosBits) == btos); }
258 bool is_char() const { return (((uintx) _flags >> tosBits) == ctos); }
259 bool is_short() const { return (((uintx) _flags >> tosBits) == stos); }
260 bool is_int() const { return (((uintx) _flags >> tosBits) == itos); }
261 bool is_long() const { return (((uintx) _flags >> tosBits) == ltos); }
262 bool is_float() const { return (((uintx) _flags >> tosBits) == ftos); }
263 bool is_double() const { return (((uintx) _flags >> tosBits) == dtos); }
264 bool is_object() const { return (((uintx) _flags >> tosBits) == atos); }
265 TosState flag_state() const { assert( ( (_flags >> tosBits) & 0x0F ) < number_of_states, "Invalid state in as_flags");
266 return (TosState)((_flags >> tosBits) & 0x0F); }
267
268 // Code generation support
269 static WordSize size() { return in_WordSize(sizeof(ConstantPoolCacheEntry) / HeapWordSize); }
270 static ByteSize size_in_bytes() { return in_ByteSize(sizeof(ConstantPoolCacheEntry)); }
271 static ByteSize indices_offset() { return byte_offset_of(ConstantPoolCacheEntry, _indices); }
272 static ByteSize f1_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f1); }
273 static ByteSize f2_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f2); }
274 static ByteSize flags_offset() { return byte_offset_of(ConstantPoolCacheEntry, _flags); }
275
276 // GC Support
277 void oops_do(void f(oop*));
278 void oop_iterate(OopClosure* blk);
279 void oop_iterate_m(OopClosure* blk, MemRegion mr);
280 void follow_contents();
281 void adjust_pointers();
282
283 #ifndef SERIALGC
284 // Parallel Old
285 void follow_contents(ParCompactionManager* cm);
286 #endif // SERIALGC
287
288 void update_pointers();
289 void update_pointers(HeapWord* beg_addr, HeapWord* end_addr);
290
291 // RedefineClasses() API support:
292 // If this constantPoolCacheEntry refers to old_method then update it
293 // to refer to new_method.
294 // trace_name_printed is set to true if the current call has
295 // printed the klass name so that other routines in the adjust_*
296 // group don't print the klass name.
297 bool adjust_method_entry(methodOop old_method, methodOop new_method,
298 bool * trace_name_printed);
299 bool is_interesting_method_entry(klassOop k);
300 bool is_field_entry() const { return (_flags & (1 << hotSwapBit)) == 0; }
301 bool is_method_entry() const { return (_flags & (1 << hotSwapBit)) != 0; }
302
303 // Debugging & Printing
304 void print (outputStream* st, int index) const;
305 void verify(outputStream* st) const;
306
307 static void verify_tosBits() {
308 assert(tosBits == 28, "interpreter now assumes tosBits is 28");
309 }
310 };
311
312
313 // A constant pool cache is a runtime data structure set aside to a constant pool. The cache
314 // holds interpreter runtime information for all field access and invoke bytecodes. The cache
315 // is created and initialized before a class is actively used (i.e., initialized), the indivi-
316 // dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*).
317
318 class constantPoolCacheOopDesc: public oopDesc {
319 friend class VMStructs;
320 private:
321 int _length;
322 constantPoolOop _constant_pool; // the corresponding constant pool
323 // If true, safe for concurrent GC processing,
324 // Set unconditionally in constantPoolCacheKlass::allocate()
325 volatile bool _is_conc_safe;
326
327 // Sizing
328 debug_only(friend class ClassVerifier;)
329 int length() const { return _length; }
330 void set_length(int length) { _length = length; }
331
332 static int header_size() { return sizeof(constantPoolCacheOopDesc) / HeapWordSize; }
333 static int object_size(int length) { return align_object_size(header_size() + length * in_words(ConstantPoolCacheEntry::size())); }
334 int object_size() { return object_size(length()); }
335
336 // Helpers
337 constantPoolOop* constant_pool_addr() { return &_constant_pool; }
338 ConstantPoolCacheEntry* base() const { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); }
339
340 friend class constantPoolCacheKlass;
341 friend class ConstantPoolCacheEntry;
342
343 public:
344 // Initialization
345 void initialize(intArray& inverse_index_map);
346
347 // Secondary indexes.
348 // They must look completely different from normal indexes.
349 // The main reason is that byte swapping is sometimes done on normal indexes.
350 // Also, some of the CP accessors do different things for secondary indexes.
351 // Finally, it is helpful for debugging to tell the two apart.
352 static bool is_secondary_index(int i) { return (i < 0); }
353 static int decode_secondary_index(int i) { assert(is_secondary_index(i), ""); return ~i; }
354 static int encode_secondary_index(int i) { assert(!is_secondary_index(i), ""); return ~i; }
355
356 // Accessors
357 void set_constant_pool(constantPoolOop pool) { oop_store_without_check((oop*)&_constant_pool, (oop)pool); }
358 constantPoolOop constant_pool() const { return _constant_pool; }
359 // Fetches the entry at the given index.
360 // The entry may be either primary or secondary.
361 // In either case the index must not be encoded or byte-swapped in any way.
362 ConstantPoolCacheEntry* entry_at(int i) const {
363 assert(0 <= i && i < length(), "index out of bounds");
364 return base() + i;
365 }
366 // Fetches the secondary entry referred to by index.
367 // The index may be a secondary index, and must not be byte-swapped.
368 ConstantPoolCacheEntry* secondary_entry_at(int i) const {
369 int raw_index = i;
370 if (is_secondary_index(i)) { // correct these on the fly
371 raw_index = decode_secondary_index(i);
372 }
373 assert(entry_at(raw_index)->is_secondary_entry(), "not a secondary entry");
374 return entry_at(raw_index);
375 }
376 // Given a primary or secondary index, fetch the corresponding primary entry.
377 // Indirect through the secondary entry, if the index is encoded as a secondary index.
378 // The index must not be byte-swapped.
379 ConstantPoolCacheEntry* main_entry_at(int i) const {
380 int primary_index = i;
381 if (is_secondary_index(i)) {
382 // run through an extra level of indirection:
383 int raw_index = decode_secondary_index(i);
384 primary_index = entry_at(raw_index)->main_entry_index();
385 }
386 assert(!entry_at(primary_index)->is_secondary_entry(), "only one level of indirection");
387 return entry_at(primary_index);
388 }
389
390 // GC support
391 // If the _length field has not been set, the size of the
392 // constantPoolCache cannot be correctly calculated.
393 bool is_conc_safe() { return _is_conc_safe; }
394 void set_is_conc_safe(bool v) { _is_conc_safe = v; }
395
396 // Code generation
397 static ByteSize base_offset() { return in_ByteSize(sizeof(constantPoolCacheOopDesc)); }
398 static ByteSize entry_offset(int raw_index) {
399 int index = raw_index;
400 if (is_secondary_index(raw_index))
401 index = decode_secondary_index(raw_index);
402 return (base_offset() + ConstantPoolCacheEntry::size_in_bytes() * index);
403 }
404
405 // RedefineClasses() API support:
406 // If any entry of this constantPoolCache points to any of
407 // old_methods, replace it with the corresponding new_method.
408 // trace_name_printed is set to true if the current call has
409 // printed the klass name so that other routines in the adjust_*
410 // group don't print the klass name.
411 void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
412 int methods_length, bool * trace_name_printed);
413 };
414
415 #endif // SHARE_VM_OOPS_CPCACHEOOP_HPP