Thu, 27 Jan 2011 16:11:27 -0800
6990754: Use native memory and reference counting to implement SymbolTable
Summary: move symbols from permgen into C heap and reference count them
Reviewed-by: never, acorn, jmasa, stefank
duke@435 | 1 | /* |
stefank@2314 | 2 | * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #ifndef SHARE_VM_MEMORY_ITERATOR_HPP |
stefank@2314 | 26 | #define SHARE_VM_MEMORY_ITERATOR_HPP |
stefank@2314 | 27 | |
stefank@2314 | 28 | #include "memory/allocation.hpp" |
stefank@2314 | 29 | #include "memory/memRegion.hpp" |
stefank@2314 | 30 | #include "runtime/prefetch.hpp" |
stefank@2314 | 31 | #include "utilities/top.hpp" |
stefank@2314 | 32 | |
duke@435 | 33 | // The following classes are C++ `closures` for iterating over objects, roots and spaces |
duke@435 | 34 | |
jrose@1424 | 35 | class CodeBlob; |
jrose@1429 | 36 | class nmethod; |
duke@435 | 37 | class ReferenceProcessor; |
ysr@1376 | 38 | class DataLayout; |
duke@435 | 39 | |
ysr@777 | 40 | // Closure provides abortability. |
ysr@777 | 41 | |
ysr@777 | 42 | class Closure : public StackObj { |
ysr@777 | 43 | protected: |
ysr@777 | 44 | bool _abort; |
ysr@777 | 45 | void set_abort() { _abort = true; } |
ysr@777 | 46 | public: |
ysr@777 | 47 | Closure() : _abort(false) {} |
ysr@777 | 48 | // A subtype can use this mechanism to indicate to some iterator mapping |
ysr@777 | 49 | // functions that the iteration should cease. |
ysr@777 | 50 | bool abort() { return _abort; } |
ysr@777 | 51 | void clear_abort() { _abort = false; } |
ysr@777 | 52 | }; |
ysr@777 | 53 | |
duke@435 | 54 | // OopClosure is used for iterating through roots (oop*) |
duke@435 | 55 | |
ysr@777 | 56 | class OopClosure : public Closure { |
duke@435 | 57 | public: |
duke@435 | 58 | ReferenceProcessor* _ref_processor; |
duke@435 | 59 | OopClosure(ReferenceProcessor* rp) : _ref_processor(rp) { } |
duke@435 | 60 | OopClosure() : _ref_processor(NULL) { } |
duke@435 | 61 | virtual void do_oop(oop* o) = 0; |
duke@435 | 62 | virtual void do_oop_v(oop* o) { do_oop(o); } |
coleenp@548 | 63 | virtual void do_oop(narrowOop* o) = 0; |
coleenp@548 | 64 | virtual void do_oop_v(narrowOop* o) { do_oop(o); } |
duke@435 | 65 | |
duke@435 | 66 | // In support of post-processing of weak links of KlassKlass objects; |
duke@435 | 67 | // see KlassKlass::oop_oop_iterate(). |
jmasa@1370 | 68 | |
jmasa@1370 | 69 | virtual const bool should_remember_klasses() const { |
jmasa@1370 | 70 | assert(!must_remember_klasses(), "Should have overriden this method."); |
jmasa@1370 | 71 | return false; |
jmasa@1370 | 72 | } |
jmasa@1370 | 73 | |
duke@435 | 74 | virtual void remember_klass(Klass* k) { /* do nothing */ } |
duke@435 | 75 | |
ysr@1376 | 76 | // In support of post-processing of weak references in |
ysr@1376 | 77 | // ProfileData (MethodDataOop) objects; see, for example, |
ysr@1376 | 78 | // VirtualCallData::oop_iterate(). |
ysr@1376 | 79 | virtual const bool should_remember_mdo() const { return false; } |
ysr@1376 | 80 | virtual void remember_mdo(DataLayout* v) { /* do nothing */ } |
ysr@1376 | 81 | |
duke@435 | 82 | // The methods below control how object iterations invoking this closure |
duke@435 | 83 | // should be performed: |
duke@435 | 84 | |
duke@435 | 85 | // If "true", invoke on header klass field. |
duke@435 | 86 | bool do_header() { return true; } // Note that this is non-virtual. |
duke@435 | 87 | // Controls how prefetching is done for invocations of this closure. |
duke@435 | 88 | Prefetch::style prefetch_style() { // Note that this is non-virtual. |
duke@435 | 89 | return Prefetch::do_none; |
duke@435 | 90 | } |
ysr@777 | 91 | |
ysr@777 | 92 | // True iff this closure may be safely applied more than once to an oop |
ysr@777 | 93 | // location without an intervening "major reset" (like the end of a GC). |
ysr@777 | 94 | virtual bool idempotent() { return false; } |
ysr@777 | 95 | virtual bool apply_to_weak_ref_discovered_field() { return false; } |
jmasa@1370 | 96 | |
jmasa@1370 | 97 | #ifdef ASSERT |
jmasa@1370 | 98 | static bool _must_remember_klasses; |
jmasa@1370 | 99 | static bool must_remember_klasses(); |
jmasa@1370 | 100 | static void set_must_remember_klasses(bool v); |
jmasa@1370 | 101 | #endif |
duke@435 | 102 | }; |
duke@435 | 103 | |
duke@435 | 104 | // ObjectClosure is used for iterating through an object space |
duke@435 | 105 | |
ysr@777 | 106 | class ObjectClosure : public Closure { |
duke@435 | 107 | public: |
duke@435 | 108 | // Called for each object. |
duke@435 | 109 | virtual void do_object(oop obj) = 0; |
duke@435 | 110 | }; |
duke@435 | 111 | |
duke@435 | 112 | |
duke@435 | 113 | class BoolObjectClosure : public ObjectClosure { |
duke@435 | 114 | public: |
duke@435 | 115 | virtual bool do_object_b(oop obj) = 0; |
duke@435 | 116 | }; |
duke@435 | 117 | |
duke@435 | 118 | // Applies an oop closure to all ref fields in objects iterated over in an |
duke@435 | 119 | // object iteration. |
duke@435 | 120 | class ObjectToOopClosure: public ObjectClosure { |
duke@435 | 121 | OopClosure* _cl; |
duke@435 | 122 | public: |
duke@435 | 123 | void do_object(oop obj); |
duke@435 | 124 | ObjectToOopClosure(OopClosure* cl) : _cl(cl) {} |
duke@435 | 125 | }; |
duke@435 | 126 | |
duke@435 | 127 | // A version of ObjectClosure with "memory" (see _previous_address below) |
duke@435 | 128 | class UpwardsObjectClosure: public BoolObjectClosure { |
duke@435 | 129 | HeapWord* _previous_address; |
duke@435 | 130 | public: |
duke@435 | 131 | UpwardsObjectClosure() : _previous_address(NULL) { } |
duke@435 | 132 | void set_previous(HeapWord* addr) { _previous_address = addr; } |
duke@435 | 133 | HeapWord* previous() { return _previous_address; } |
duke@435 | 134 | // A return value of "true" can be used by the caller to decide |
duke@435 | 135 | // if this object's end should *NOT* be recorded in |
duke@435 | 136 | // _previous_address above. |
duke@435 | 137 | virtual bool do_object_bm(oop obj, MemRegion mr) = 0; |
duke@435 | 138 | }; |
duke@435 | 139 | |
duke@435 | 140 | // A version of ObjectClosure that is expected to be robust |
duke@435 | 141 | // in the face of possibly uninitialized objects. |
duke@435 | 142 | class ObjectClosureCareful : public ObjectClosure { |
duke@435 | 143 | public: |
duke@435 | 144 | virtual size_t do_object_careful_m(oop p, MemRegion mr) = 0; |
duke@435 | 145 | virtual size_t do_object_careful(oop p) = 0; |
duke@435 | 146 | }; |
duke@435 | 147 | |
duke@435 | 148 | // The following are used in CompactibleFreeListSpace and |
duke@435 | 149 | // ConcurrentMarkSweepGeneration. |
duke@435 | 150 | |
duke@435 | 151 | // Blk closure (abstract class) |
duke@435 | 152 | class BlkClosure : public StackObj { |
duke@435 | 153 | public: |
duke@435 | 154 | virtual size_t do_blk(HeapWord* addr) = 0; |
duke@435 | 155 | }; |
duke@435 | 156 | |
duke@435 | 157 | // A version of BlkClosure that is expected to be robust |
duke@435 | 158 | // in the face of possibly uninitialized objects. |
duke@435 | 159 | class BlkClosureCareful : public BlkClosure { |
duke@435 | 160 | public: |
duke@435 | 161 | size_t do_blk(HeapWord* addr) { |
duke@435 | 162 | guarantee(false, "call do_blk_careful instead"); |
duke@435 | 163 | return 0; |
duke@435 | 164 | } |
duke@435 | 165 | virtual size_t do_blk_careful(HeapWord* addr) = 0; |
duke@435 | 166 | }; |
duke@435 | 167 | |
duke@435 | 168 | // SpaceClosure is used for iterating over spaces |
duke@435 | 169 | |
duke@435 | 170 | class Space; |
duke@435 | 171 | class CompactibleSpace; |
duke@435 | 172 | |
duke@435 | 173 | class SpaceClosure : public StackObj { |
duke@435 | 174 | public: |
duke@435 | 175 | // Called for each space |
duke@435 | 176 | virtual void do_space(Space* s) = 0; |
duke@435 | 177 | }; |
duke@435 | 178 | |
duke@435 | 179 | class CompactibleSpaceClosure : public StackObj { |
duke@435 | 180 | public: |
duke@435 | 181 | // Called for each compactible space |
duke@435 | 182 | virtual void do_space(CompactibleSpace* s) = 0; |
duke@435 | 183 | }; |
duke@435 | 184 | |
duke@435 | 185 | |
jrose@1424 | 186 | // CodeBlobClosure is used for iterating through code blobs |
jrose@1424 | 187 | // in the code cache or on thread stacks |
jrose@1424 | 188 | |
jrose@1424 | 189 | class CodeBlobClosure : public Closure { |
jrose@1424 | 190 | public: |
jrose@1424 | 191 | // Called for each code blob. |
jrose@1424 | 192 | virtual void do_code_blob(CodeBlob* cb) = 0; |
jrose@1424 | 193 | }; |
jrose@1424 | 194 | |
jrose@1424 | 195 | |
jrose@1424 | 196 | class MarkingCodeBlobClosure : public CodeBlobClosure { |
jrose@1424 | 197 | public: |
jrose@1424 | 198 | // Called for each code blob, but at most once per unique blob. |
jrose@1429 | 199 | virtual void do_newly_marked_nmethod(nmethod* nm) = 0; |
jrose@1424 | 200 | |
jrose@1424 | 201 | virtual void do_code_blob(CodeBlob* cb); |
jrose@1424 | 202 | // = { if (!nmethod(cb)->test_set_oops_do_mark()) do_newly_marked_nmethod(cb); } |
jrose@1424 | 203 | |
jrose@1424 | 204 | class MarkScope : public StackObj { |
jrose@1424 | 205 | protected: |
jrose@1424 | 206 | bool _active; |
jrose@1424 | 207 | public: |
jrose@1424 | 208 | MarkScope(bool activate = true); |
jrose@1424 | 209 | // = { if (active) nmethod::oops_do_marking_prologue(); } |
jrose@1424 | 210 | ~MarkScope(); |
jrose@1424 | 211 | // = { if (active) nmethod::oops_do_marking_epilogue(); } |
jrose@1424 | 212 | }; |
jrose@1424 | 213 | }; |
jrose@1424 | 214 | |
jrose@1424 | 215 | |
jrose@1424 | 216 | // Applies an oop closure to all ref fields in code blobs |
jrose@1424 | 217 | // iterated over in an object iteration. |
jrose@1424 | 218 | class CodeBlobToOopClosure: public MarkingCodeBlobClosure { |
jrose@1424 | 219 | OopClosure* _cl; |
jrose@1424 | 220 | bool _do_marking; |
jrose@1424 | 221 | public: |
jrose@1429 | 222 | virtual void do_newly_marked_nmethod(nmethod* cb); |
jrose@1424 | 223 | // = { cb->oops_do(_cl); } |
jrose@1424 | 224 | virtual void do_code_blob(CodeBlob* cb); |
jrose@1424 | 225 | // = { if (_do_marking) super::do_code_blob(cb); else cb->oops_do(_cl); } |
jrose@1424 | 226 | CodeBlobToOopClosure(OopClosure* cl, bool do_marking) |
jrose@1424 | 227 | : _cl(cl), _do_marking(do_marking) {} |
jrose@1424 | 228 | }; |
jrose@1424 | 229 | |
jrose@1424 | 230 | |
duke@435 | 231 | |
duke@435 | 232 | // MonitorClosure is used for iterating over monitors in the monitors cache |
duke@435 | 233 | |
duke@435 | 234 | class ObjectMonitor; |
duke@435 | 235 | |
duke@435 | 236 | class MonitorClosure : public StackObj { |
duke@435 | 237 | public: |
duke@435 | 238 | // called for each monitor in cache |
duke@435 | 239 | virtual void do_monitor(ObjectMonitor* m) = 0; |
duke@435 | 240 | }; |
duke@435 | 241 | |
duke@435 | 242 | // A closure that is applied without any arguments. |
duke@435 | 243 | class VoidClosure : public StackObj { |
duke@435 | 244 | public: |
duke@435 | 245 | // I would have liked to declare this a pure virtual, but that breaks |
duke@435 | 246 | // in mysterious ways, for unknown reasons. |
duke@435 | 247 | virtual void do_void(); |
duke@435 | 248 | }; |
duke@435 | 249 | |
duke@435 | 250 | |
duke@435 | 251 | // YieldClosure is intended for use by iteration loops |
duke@435 | 252 | // to incrementalize their work, allowing interleaving |
duke@435 | 253 | // of an interruptable task so as to allow other |
duke@435 | 254 | // threads to run (which may not otherwise be able to access |
duke@435 | 255 | // exclusive resources, for instance). Additionally, the |
duke@435 | 256 | // closure also allows for aborting an ongoing iteration |
duke@435 | 257 | // by means of checking the return value from the polling |
duke@435 | 258 | // call. |
duke@435 | 259 | class YieldClosure : public StackObj { |
duke@435 | 260 | public: |
duke@435 | 261 | virtual bool should_return() = 0; |
duke@435 | 262 | }; |
duke@435 | 263 | |
duke@435 | 264 | // Abstract closure for serializing data (read or write). |
duke@435 | 265 | |
duke@435 | 266 | class SerializeOopClosure : public OopClosure { |
duke@435 | 267 | public: |
duke@435 | 268 | // Return bool indicating whether closure implements read or write. |
duke@435 | 269 | virtual bool reading() const = 0; |
duke@435 | 270 | |
duke@435 | 271 | // Read/write the int pointed to by i. |
duke@435 | 272 | virtual void do_int(int* i) = 0; |
duke@435 | 273 | |
duke@435 | 274 | // Read/write the size_t pointed to by i. |
duke@435 | 275 | virtual void do_size_t(size_t* i) = 0; |
duke@435 | 276 | |
duke@435 | 277 | // Read/write the void pointer pointed to by p. |
duke@435 | 278 | virtual void do_ptr(void** p) = 0; |
duke@435 | 279 | |
duke@435 | 280 | // Read/write the HeapWord pointer pointed to be p. |
duke@435 | 281 | virtual void do_ptr(HeapWord** p) = 0; |
duke@435 | 282 | |
duke@435 | 283 | // Read/write the region specified. |
duke@435 | 284 | virtual void do_region(u_char* start, size_t size) = 0; |
duke@435 | 285 | |
duke@435 | 286 | // Check/write the tag. If reading, then compare the tag against |
duke@435 | 287 | // the passed in value and fail is they don't match. This allows |
duke@435 | 288 | // for verification that sections of the serialized data are of the |
duke@435 | 289 | // correct length. |
duke@435 | 290 | virtual void do_tag(int tag) = 0; |
duke@435 | 291 | }; |
jmasa@1370 | 292 | |
coleenp@2497 | 293 | class SymbolClosure : public StackObj { |
coleenp@2497 | 294 | public: |
coleenp@2497 | 295 | virtual void do_symbol(Symbol**) = 0; |
coleenp@2497 | 296 | |
coleenp@2497 | 297 | // Clear LSB in symbol address; it can be set by CPSlot. |
coleenp@2497 | 298 | static Symbol* load_symbol(Symbol** p) { |
coleenp@2497 | 299 | return (Symbol*)(intptr_t(*p) & ~1); |
coleenp@2497 | 300 | } |
coleenp@2497 | 301 | |
coleenp@2497 | 302 | // Store symbol, adjusting new pointer if the original pointer was adjusted |
coleenp@2497 | 303 | // (symbol references in constant pool slots have their LSB set to 1). |
coleenp@2497 | 304 | static void store_symbol(Symbol** p, Symbol* sym) { |
coleenp@2497 | 305 | *p = (Symbol*)(intptr_t(sym) | (intptr_t(*p) & 1)); |
coleenp@2497 | 306 | } |
coleenp@2497 | 307 | }; |
coleenp@2497 | 308 | |
jmasa@1370 | 309 | #ifdef ASSERT |
jmasa@1370 | 310 | // This class is used to flag phases of a collection that |
jmasa@1370 | 311 | // can unload classes and which should override the |
jmasa@1370 | 312 | // should_remember_klasses() and remember_klass() of OopClosure. |
jmasa@1370 | 313 | // The _must_remember_klasses is set in the contructor and restored |
jmasa@1370 | 314 | // in the destructor. _must_remember_klasses is checked in assertions |
jmasa@1370 | 315 | // in the OopClosure implementations of should_remember_klasses() and |
jmasa@1370 | 316 | // remember_klass() and the expectation is that the OopClosure |
jmasa@1370 | 317 | // implementation should not be in use if _must_remember_klasses is set. |
jmasa@1370 | 318 | // Instances of RememberKlassesChecker can be place in |
jmasa@1370 | 319 | // marking phases of collections which can do class unloading. |
jmasa@1370 | 320 | // RememberKlassesChecker can be passed "false" to turn off checking. |
jmasa@1370 | 321 | // It is used by CMS when CMS yields to a different collector. |
jmasa@1370 | 322 | class RememberKlassesChecker: StackObj { |
jmasa@1625 | 323 | bool _saved_state; |
jmasa@1625 | 324 | bool _do_check; |
jmasa@1370 | 325 | public: |
jmasa@1625 | 326 | RememberKlassesChecker(bool checking_on) : _saved_state(false), |
jmasa@1625 | 327 | _do_check(true) { |
jmasa@1625 | 328 | // The ClassUnloading unloading flag affects the collectors except |
jmasa@1625 | 329 | // for CMS. |
jmasa@1625 | 330 | // CMS unloads classes if CMSClassUnloadingEnabled is true or |
jmasa@1625 | 331 | // if ExplicitGCInvokesConcurrentAndUnloadsClasses is true and |
jmasa@1625 | 332 | // the current collection is an explicit collection. Turning |
jmasa@1625 | 333 | // on the checking in general for |
jmasa@1625 | 334 | // ExplicitGCInvokesConcurrentAndUnloadsClasses and |
jmasa@1625 | 335 | // UseConcMarkSweepGC should not lead to false positives. |
jmasa@1625 | 336 | _do_check = |
jmasa@1625 | 337 | ClassUnloading && !UseConcMarkSweepGC || |
jmasa@1625 | 338 | CMSClassUnloadingEnabled && UseConcMarkSweepGC || |
jmasa@1625 | 339 | ExplicitGCInvokesConcurrentAndUnloadsClasses && UseConcMarkSweepGC; |
jmasa@1625 | 340 | if (_do_check) { |
jmasa@1625 | 341 | _saved_state = OopClosure::must_remember_klasses(); |
jmasa@1625 | 342 | OopClosure::set_must_remember_klasses(checking_on); |
jmasa@1370 | 343 | } |
jmasa@1370 | 344 | } |
jmasa@1370 | 345 | ~RememberKlassesChecker() { |
jmasa@1625 | 346 | if (_do_check) { |
jmasa@1625 | 347 | OopClosure::set_must_remember_klasses(_saved_state); |
jmasa@1370 | 348 | } |
jmasa@1370 | 349 | } |
jmasa@1370 | 350 | }; |
jmasa@1370 | 351 | #endif // ASSERT |
stefank@2314 | 352 | |
stefank@2314 | 353 | #endif // SHARE_VM_MEMORY_ITERATOR_HPP |