Sat, 30 Oct 2010 11:45:35 -0700
6981788: GC map generator sometimes picks up the wrong kind of instruction operand
Summary: Distinguish pool indexes from cache indexes in recently changed code.
Reviewed-by: never
1 /*
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25 // A ConstantPoolCacheEntry describes an individual entry of the constant
26 // pool cache. There's 2 principal kinds of entries: field entries for in-
27 // stance & static field access, and method entries for invokes. Some of
28 // the entry layout is shared and looks as follows:
29 //
30 // bit number |31 0|
31 // bit length |-8--|-8--|---16----|
32 // --------------------------------
33 // _indices [ b2 | b1 | index ]
34 // _f1 [ entry specific ]
35 // _f2 [ entry specific ]
36 // _flags [t|f|vf|v|m|h|unused|field_index] (for field entries)
37 // bit length |4|1|1 |1|1|0|---7--|----16-----]
38 // _flags [t|f|vf|v|m|h|unused|eidx|psze] (for method entries)
39 // bit length |4|1|1 |1|1|1|---7--|-8--|-8--]
41 // --------------------------------
42 //
43 // with:
44 // index = original constant pool index
45 // b1 = bytecode 1
46 // b2 = bytecode 2
47 // psze = parameters size (method entries only)
48 // eidx = interpreter entry index (method entries only)
49 // field_index = index into field information in holder instanceKlass
50 // The index max is 0xffff (max number of fields in constant pool)
51 // and is multiplied by (instanceKlass::next_offset) when accessing.
52 // t = TosState (see below)
53 // f = field is marked final (see below)
54 // vf = virtual, final (method entries only : is_vfinal())
55 // v = field is volatile (see below)
56 // m = invokeinterface used for method in class Object (see below)
57 // h = RedefineClasses/Hotswap bit (see below)
58 //
59 // The flags after TosState have the following interpretation:
60 // bit 27: f flag true if field is marked final
61 // bit 26: vf flag true if virtual final method
62 // bit 25: v flag true if field is volatile (only for fields)
63 // bit 24: m flag true if invokeinterface used for method in class Object
64 // bit 23: 0 for fields, 1 for methods
65 //
66 // The flags 31, 30, 29, 28 together build a 4 bit number 0 to 8 with the
67 // following mapping to the TosState states:
68 //
69 // btos: 0
70 // ctos: 1
71 // stos: 2
72 // itos: 3
73 // ltos: 4
74 // ftos: 5
75 // dtos: 6
76 // atos: 7
77 // vtos: 8
78 //
79 // Entry specific: field entries:
80 // _indices = get (b1 section) and put (b2 section) bytecodes, original constant pool index
81 // _f1 = field holder
82 // _f2 = field offset in words
83 // _flags = field type information, original field index in field holder
84 // (field_index section)
85 //
86 // Entry specific: method entries:
87 // _indices = invoke code for f1 (b1 section), invoke code for f2 (b2 section),
88 // original constant pool index
89 // _f1 = method for all but virtual calls, unused by virtual calls
90 // (note: for interface calls, which are essentially virtual,
91 // contains klassOop for the corresponding interface.
92 // for invokedynamic, f1 contains the CallSite object for the invocation
93 // _f2 = method/vtable index for virtual calls only, unused by all other
94 // calls. The vf flag indicates this is a method pointer not an
95 // index.
96 // _flags = field type info (f section),
97 // virtual final entry (vf),
98 // interpreter entry index (eidx section),
99 // parameter size (psze section)
100 //
101 // Note: invokevirtual & invokespecial bytecodes can share the same constant
102 // pool entry and thus the same constant pool cache entry. All invoke
103 // bytecodes but invokevirtual use only _f1 and the corresponding b1
104 // bytecode, while invokevirtual uses only _f2 and the corresponding
105 // b2 bytecode. The value of _flags is shared for both types of entries.
106 //
107 // The fields are volatile so that they are stored in the order written in the
108 // source code. The _indices field with the bytecode must be written last.
110 class ConstantPoolCacheEntry VALUE_OBJ_CLASS_SPEC {
111 friend class VMStructs;
112 friend class constantPoolCacheKlass;
113 friend class constantPoolOopDesc; //resolve_constant_at_impl => set_f1
115 private:
116 volatile intx _indices; // constant pool index & rewrite bytecodes
117 volatile oop _f1; // entry specific oop field
118 volatile intx _f2; // entry specific int/oop field
119 volatile intx _flags; // flags
122 #ifdef ASSERT
123 bool same_methodOop(oop cur_f1, oop f1);
124 #endif
126 void set_bytecode_1(Bytecodes::Code code);
127 void set_bytecode_2(Bytecodes::Code code);
128 void set_f1(oop f1) {
129 oop existing_f1 = _f1; // read once
130 assert(existing_f1 == NULL || existing_f1 == f1, "illegal field change");
131 oop_store(&_f1, f1);
132 }
133 void set_f1_if_null_atomic(oop f1);
134 void set_f2(intx f2) { assert(_f2 == 0 || _f2 == f2, "illegal field change"); _f2 = f2; }
135 int as_flags(TosState state, bool is_final, bool is_vfinal, bool is_volatile,
136 bool is_method_interface, bool is_method);
137 void set_flags(intx flags) { _flags = flags; }
139 public:
140 // specific bit values in flag field
141 // Note: the interpreter knows this layout!
142 enum FlagBitValues {
143 hotSwapBit = 23,
144 methodInterface = 24,
145 volatileField = 25,
146 vfinalMethod = 26,
147 finalField = 27
148 };
150 enum { field_index_mask = 0xFFFF };
152 // start of type bits in flags
153 // Note: the interpreter knows this layout!
154 enum FlagValues {
155 tosBits = 28
156 };
158 // Initialization
159 void initialize_entry(int original_index); // initialize primary entry
160 void initialize_secondary_entry(int main_index); // initialize secondary entry
162 void set_field( // sets entry to resolved field state
163 Bytecodes::Code get_code, // the bytecode used for reading the field
164 Bytecodes::Code put_code, // the bytecode used for writing the field
165 KlassHandle field_holder, // the object/klass holding the field
166 int orig_field_index, // the original field index in the field holder
167 int field_offset, // the field offset in words in the field holder
168 TosState field_type, // the (machine) field type
169 bool is_final, // the field is final
170 bool is_volatile // the field is volatile
171 );
173 void set_method( // sets entry to resolved method entry
174 Bytecodes::Code invoke_code, // the bytecode used for invoking the method
175 methodHandle method, // the method/prototype if any (NULL, otherwise)
176 int vtable_index // the vtable index if any, else negative
177 );
179 void set_interface_call(
180 methodHandle method, // Resolved method
181 int index // Method index into interface
182 );
184 void set_dynamic_call(
185 Handle call_site, // Resolved java.dyn.CallSite (f1)
186 methodHandle signature_invoker // determines signature information
187 );
189 // For JVM_CONSTANT_InvokeDynamic cache entries:
190 void initialize_bootstrap_method_index_in_cache(int bsm_cache_index);
191 int bootstrap_method_index_in_cache();
193 void set_parameter_size(int value) {
194 assert(parameter_size() == 0 || parameter_size() == value,
195 "size must not change");
196 // Setting the parameter size by itself is only safe if the
197 // current value of _flags is 0, otherwise another thread may have
198 // updated it and we don't want to overwrite that value. Don't
199 // bother trying to update it once it's nonzero but always make
200 // sure that the final parameter size agrees with what was passed.
201 if (_flags == 0) {
202 Atomic::cmpxchg_ptr((value & 0xFF), &_flags, 0);
203 }
204 guarantee(parameter_size() == value, "size must not change");
205 }
207 // Which bytecode number (1 or 2) in the index field is valid for this bytecode?
208 // Returns -1 if neither is valid.
209 static int bytecode_number(Bytecodes::Code code) {
210 switch (code) {
211 case Bytecodes::_getstatic : // fall through
212 case Bytecodes::_getfield : // fall through
213 case Bytecodes::_invokespecial : // fall through
214 case Bytecodes::_invokestatic : // fall through
215 case Bytecodes::_invokedynamic : // fall through
216 case Bytecodes::_invokeinterface : return 1;
217 case Bytecodes::_putstatic : // fall through
218 case Bytecodes::_putfield : // fall through
219 case Bytecodes::_invokevirtual : return 2;
220 default : break;
221 }
222 return -1;
223 }
225 // Has this bytecode been resolved? Only valid for invokes and get/put field/static.
226 bool is_resolved(Bytecodes::Code code) const {
227 switch (bytecode_number(code)) {
228 case 1: return (bytecode_1() == code);
229 case 2: return (bytecode_2() == code);
230 }
231 return false; // default: not resolved
232 }
234 // Accessors
235 bool is_secondary_entry() const { return (_indices & 0xFFFF) == 0; }
236 int constant_pool_index() const { assert((_indices & 0xFFFF) != 0, "must be main entry");
237 return (_indices & 0xFFFF); }
238 int main_entry_index() const { assert((_indices & 0xFFFF) == 0, "must be secondary entry");
239 return ((uintx)_indices >> 16); }
240 Bytecodes::Code bytecode_1() const { return Bytecodes::cast((_indices >> 16) & 0xFF); }
241 Bytecodes::Code bytecode_2() const { return Bytecodes::cast((_indices >> 24) & 0xFF); }
242 volatile oop f1() const { return _f1; }
243 bool is_f1_null() const { return (oop)_f1 == NULL; } // classifies a CPC entry as unbound
244 intx f2() const { return _f2; }
245 int field_index() const;
246 int parameter_size() const { return _flags & 0xFF; }
247 bool is_vfinal() const { return ((_flags & (1 << vfinalMethod)) == (1 << vfinalMethod)); }
248 bool is_volatile() const { return ((_flags & (1 << volatileField)) == (1 << volatileField)); }
249 bool is_methodInterface() const { return ((_flags & (1 << methodInterface)) == (1 << methodInterface)); }
250 bool is_byte() const { return (((uintx) _flags >> tosBits) == btos); }
251 bool is_char() const { return (((uintx) _flags >> tosBits) == ctos); }
252 bool is_short() const { return (((uintx) _flags >> tosBits) == stos); }
253 bool is_int() const { return (((uintx) _flags >> tosBits) == itos); }
254 bool is_long() const { return (((uintx) _flags >> tosBits) == ltos); }
255 bool is_float() const { return (((uintx) _flags >> tosBits) == ftos); }
256 bool is_double() const { return (((uintx) _flags >> tosBits) == dtos); }
257 bool is_object() const { return (((uintx) _flags >> tosBits) == atos); }
258 TosState flag_state() const { assert( ( (_flags >> tosBits) & 0x0F ) < number_of_states, "Invalid state in as_flags");
259 return (TosState)((_flags >> tosBits) & 0x0F); }
261 // Code generation support
262 static WordSize size() { return in_WordSize(sizeof(ConstantPoolCacheEntry) / HeapWordSize); }
263 static ByteSize size_in_bytes() { return in_ByteSize(sizeof(ConstantPoolCacheEntry)); }
264 static ByteSize indices_offset() { return byte_offset_of(ConstantPoolCacheEntry, _indices); }
265 static ByteSize f1_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f1); }
266 static ByteSize f2_offset() { return byte_offset_of(ConstantPoolCacheEntry, _f2); }
267 static ByteSize flags_offset() { return byte_offset_of(ConstantPoolCacheEntry, _flags); }
269 // GC Support
270 void oops_do(void f(oop*));
271 void oop_iterate(OopClosure* blk);
272 void oop_iterate_m(OopClosure* blk, MemRegion mr);
273 void follow_contents();
274 void adjust_pointers();
276 #ifndef SERIALGC
277 // Parallel Old
278 void follow_contents(ParCompactionManager* cm);
279 #endif // SERIALGC
281 void update_pointers();
282 void update_pointers(HeapWord* beg_addr, HeapWord* end_addr);
284 // RedefineClasses() API support:
285 // If this constantPoolCacheEntry refers to old_method then update it
286 // to refer to new_method.
287 // trace_name_printed is set to true if the current call has
288 // printed the klass name so that other routines in the adjust_*
289 // group don't print the klass name.
290 bool adjust_method_entry(methodOop old_method, methodOop new_method,
291 bool * trace_name_printed);
292 bool is_interesting_method_entry(klassOop k);
293 bool is_field_entry() const { return (_flags & (1 << hotSwapBit)) == 0; }
294 bool is_method_entry() const { return (_flags & (1 << hotSwapBit)) != 0; }
296 // Debugging & Printing
297 void print (outputStream* st, int index) const;
298 void verify(outputStream* st) const;
300 static void verify_tosBits() {
301 assert(tosBits == 28, "interpreter now assumes tosBits is 28");
302 }
303 };
306 // A constant pool cache is a runtime data structure set aside to a constant pool. The cache
307 // holds interpreter runtime information for all field access and invoke bytecodes. The cache
308 // is created and initialized before a class is actively used (i.e., initialized), the indivi-
309 // dual cache entries are filled at resolution (i.e., "link") time (see also: rewriter.*).
311 class constantPoolCacheOopDesc: public oopDesc {
312 friend class VMStructs;
313 private:
314 int _length;
315 constantPoolOop _constant_pool; // the corresponding constant pool
316 // If true, safe for concurrent GC processing,
317 // Set unconditionally in constantPoolCacheKlass::allocate()
318 volatile bool _is_conc_safe;
320 // Sizing
321 debug_only(friend class ClassVerifier;)
322 int length() const { return _length; }
323 void set_length(int length) { _length = length; }
325 static int header_size() { return sizeof(constantPoolCacheOopDesc) / HeapWordSize; }
326 static int object_size(int length) { return align_object_size(header_size() + length * in_words(ConstantPoolCacheEntry::size())); }
327 int object_size() { return object_size(length()); }
329 // Helpers
330 constantPoolOop* constant_pool_addr() { return &_constant_pool; }
331 ConstantPoolCacheEntry* base() const { return (ConstantPoolCacheEntry*)((address)this + in_bytes(base_offset())); }
333 friend class constantPoolCacheKlass;
334 friend class ConstantPoolCacheEntry;
336 public:
337 // Initialization
338 void initialize(intArray& inverse_index_map);
340 // Secondary indexes.
341 // They must look completely different from normal indexes.
342 // The main reason is that byte swapping is sometimes done on normal indexes.
343 // Also, some of the CP accessors do different things for secondary indexes.
344 // Finally, it is helpful for debugging to tell the two apart.
345 static bool is_secondary_index(int i) { return (i < 0); }
346 static int decode_secondary_index(int i) { assert(is_secondary_index(i), ""); return ~i; }
347 static int encode_secondary_index(int i) { assert(!is_secondary_index(i), ""); return ~i; }
349 // Accessors
350 void set_constant_pool(constantPoolOop pool) { oop_store_without_check((oop*)&_constant_pool, (oop)pool); }
351 constantPoolOop constant_pool() const { return _constant_pool; }
352 // Fetches the entry at the given index.
353 // The entry may be either primary or secondary.
354 // In either case the index must not be encoded or byte-swapped in any way.
355 ConstantPoolCacheEntry* entry_at(int i) const {
356 assert(0 <= i && i < length(), "index out of bounds");
357 return base() + i;
358 }
359 // Fetches the secondary entry referred to by index.
360 // The index may be a secondary index, and must not be byte-swapped.
361 ConstantPoolCacheEntry* secondary_entry_at(int i) const {
362 int raw_index = i;
363 if (is_secondary_index(i)) { // correct these on the fly
364 raw_index = decode_secondary_index(i);
365 }
366 assert(entry_at(raw_index)->is_secondary_entry(), "not a secondary entry");
367 return entry_at(raw_index);
368 }
369 // Given a primary or secondary index, fetch the corresponding primary entry.
370 // Indirect through the secondary entry, if the index is encoded as a secondary index.
371 // The index must not be byte-swapped.
372 ConstantPoolCacheEntry* main_entry_at(int i) const {
373 int primary_index = i;
374 if (is_secondary_index(i)) {
375 // run through an extra level of indirection:
376 int raw_index = decode_secondary_index(i);
377 primary_index = entry_at(raw_index)->main_entry_index();
378 }
379 assert(!entry_at(primary_index)->is_secondary_entry(), "only one level of indirection");
380 return entry_at(primary_index);
381 }
383 // GC support
384 // If the _length field has not been set, the size of the
385 // constantPoolCache cannot be correctly calculated.
386 bool is_conc_safe() { return _is_conc_safe; }
387 void set_is_conc_safe(bool v) { _is_conc_safe = v; }
389 // Code generation
390 static ByteSize base_offset() { return in_ByteSize(sizeof(constantPoolCacheOopDesc)); }
391 static ByteSize entry_offset(int raw_index) {
392 int index = raw_index;
393 if (is_secondary_index(raw_index))
394 index = decode_secondary_index(raw_index);
395 return (base_offset() + ConstantPoolCacheEntry::size_in_bytes() * index);
396 }
398 // RedefineClasses() API support:
399 // If any entry of this constantPoolCache points to any of
400 // old_methods, replace it with the corresponding new_method.
401 // trace_name_printed is set to true if the current call has
402 // printed the klass name so that other routines in the adjust_*
403 // group don't print the klass name.
404 void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,
405 int methods_length, bool * trace_name_printed);
406 };