1 /*

     2  * Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #ifndef SHARE_VM_COMPILER_OOPMAP_HPP

    26 #define SHARE_VM_COMPILER_OOPMAP_HPP

    27 

    28 #include "code/compressedStream.hpp"

    29 #include "code/vmreg.hpp"

    30 #include "memory/allocation.hpp"

    31 #include "utilities/growableArray.hpp"

    32 

    33 // Interface for generating the frame map for compiled code.  A frame map

    34 // describes for a specific pc whether each register and frame stack slot is:

    35 //   Oop         - A GC root for current frame

    36 //   Dead        - Dead; can be Zapped for debugging

    37 //   CalleeXX    - Callee saved; also describes which caller register is saved

    38 //   DerivedXX   - A derived oop; original oop is described.

    39 //

    40 // OopMapValue describes a single OopMap entry

    41 

    42 class frame;

    43 class RegisterMap;

    44 class DerivedPointerEntry;

    45 

    46 class OopMapValue: public StackObj {

    47   friend class VMStructs;

    48 private:

    49   short _value;

    50   int value() const                                 { return _value; }

    51   void set_value(int value)                         { _value = value; }

    52   short _content_reg;

    53 

    54 public:

    55   // Constants

    56   enum { type_bits                = 4,

    57          register_bits            = BitsPerShort - type_bits };

    58 

    59   enum { type_shift               = 0,

    60          register_shift           = type_bits };

    61 

    62   enum { type_mask                = right_n_bits(type_bits),

    63          type_mask_in_place       = type_mask << type_shift,

    64          register_mask            = right_n_bits(register_bits),

    65          register_mask_in_place   = register_mask << register_shift };

    66 

    67   enum oop_types {              // must fit in type_bits

    68          unused_value =0,       // powers of 2, for masking OopMapStream

    69          oop_value = 1,

    70          narrowoop_value = 2,

    71          callee_saved_value = 4,

    72          derived_oop_value= 8 };

    73 

    74   // Constructors

    75   OopMapValue () { set_value(0); set_content_reg(VMRegImpl::Bad()); }

    76   OopMapValue (VMReg reg, oop_types t) { set_reg_type(reg, t); set_content_reg(VMRegImpl::Bad()); }

    77   OopMapValue (VMReg reg, oop_types t, VMReg reg2) { set_reg_type(reg, t); set_content_reg(reg2); }

    78   OopMapValue (CompressedReadStream* stream) { read_from(stream); }

    79 

    80   // Archiving

    81   void write_on(CompressedWriteStream* stream) {

    82     stream->write_int(value());

    83     if(is_callee_saved() || is_derived_oop()) {

    84       stream->write_int(content_reg()->value());

    85     }

    86   }

    87 

    88   void read_from(CompressedReadStream* stream) {

    89     set_value(stream->read_int());

    90     if (is_callee_saved() || is_derived_oop()) {

    91       set_content_reg(VMRegImpl::as_VMReg(stream->read_int(), true));

    92     }

    93   }

    94 

    95   // Querying

    96   bool is_oop()               { return mask_bits(value(), type_mask_in_place) == oop_value; }

    97   bool is_narrowoop()           { return mask_bits(value(), type_mask_in_place) == narrowoop_value; }

    98   bool is_callee_saved()      { return mask_bits(value(), type_mask_in_place) == callee_saved_value; }

    99   bool is_derived_oop()       { return mask_bits(value(), type_mask_in_place) == derived_oop_value; }

   100 

   101   void set_oop()              { set_value((value() & register_mask_in_place) | oop_value); }

   102   void set_narrowoop()          { set_value((value() & register_mask_in_place) | narrowoop_value); }

   103   void set_callee_saved()     { set_value((value() & register_mask_in_place) | callee_saved_value); }

   104   void set_derived_oop()      { set_value((value() & register_mask_in_place) | derived_oop_value); }

   105 

   106   VMReg reg() const { return VMRegImpl::as_VMReg(mask_bits(value(), register_mask_in_place) >> register_shift); }

   107   oop_types type() const      { return (oop_types)mask_bits(value(), type_mask_in_place); }

   108 

   109   static bool legal_vm_reg_name(VMReg p) {

   110     return (p->value()  == (p->value() & register_mask));

   111   }

   112 

   113   void set_reg_type(VMReg p, oop_types t) {

   114     set_value((p->value() << register_shift) | t);

   115     assert(reg() == p, "sanity check" );

   116     assert(type() == t, "sanity check" );

   117   }

   118 

   119 

   120   VMReg content_reg() const       { return VMRegImpl::as_VMReg(_content_reg, true); }

   121   void set_content_reg(VMReg r)   { _content_reg = r->value(); }

   122 

   123   // Physical location queries

   124   bool is_register_loc()      { return reg()->is_reg(); }

   125   bool is_stack_loc()         { return reg()->is_stack(); }

   126 

   127   // Returns offset from sp.

   128   int stack_offset() {

   129     assert(is_stack_loc(), "must be stack location");

   130     return reg()->reg2stack();

   131   }

   132 

   133   void print_on(outputStream* st) const;

   134   void print() const { print_on(tty); }

   135 };

   136 

   137 

   138 class OopMap: public ResourceObj {

   139   friend class OopMapStream;

   140   friend class VMStructs;

   141  private:

   142   int  _pc_offset; // offset in the code that this OopMap corresponds to

   143   int  _omv_count; // number of OopMapValues in the stream

   144   CompressedWriteStream* _write_stream;

   145 

   146   debug_only( OopMapValue::oop_types* _locs_used; int _locs_length;)

   147 

   148   // Accessors

   149   int omv_count() const                       { return _omv_count; }

   150   void set_omv_count(int value)               { _omv_count = value; }

   151   void increment_count()                      { _omv_count++; }

   152   CompressedWriteStream* write_stream() const { return _write_stream; }

   153   void set_write_stream(CompressedWriteStream* value) { _write_stream = value; }

   154 

   155  private:

   156   enum DeepCopyToken { _deep_copy_token };

   157   OopMap(DeepCopyToken, OopMap* source);  // used only by deep_copy

   158 

   159  public:

   160   OopMap(int frame_size, int arg_count);

   161 

   162   // pc-offset handling

   163   int offset() const     { return _pc_offset; }

   164   void set_offset(int o) { _pc_offset = o; }

   165   int count() const { return _omv_count; }

   166   int data_size() const  { return write_stream()->position(); }

   167   address data() const { return write_stream()->buffer(); }

   168 

   169   // Check to avoid double insertion

   170   debug_only(OopMapValue::oop_types locs_used( int indx ) { return _locs_used[indx]; })

   171 

   172   // Construction

   173   // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd

   174   // slots to hold 4-byte values like ints and floats in the LP64 build.

   175   void set_oop  ( VMReg local);

   176   void set_value( VMReg local);

   177   void set_narrowoop(VMReg local);

   178   void set_dead ( VMReg local);

   179   void set_callee_saved( VMReg local, VMReg caller_machine_register );

   180   void set_derived_oop ( VMReg local, VMReg derived_from_local_register );

   181   void set_xxx(VMReg reg, OopMapValue::oop_types x, VMReg optional);

   182 

   183   int heap_size() const;

   184   void copy_data_to(address addr) const;

   185   OopMap* deep_copy();

   186 

   187   bool has_derived_pointer() const PRODUCT_RETURN0;

   188 

   189   bool legal_vm_reg_name(VMReg local) {

   190      return OopMapValue::legal_vm_reg_name(local);

   191   }

   192 

   193   // Printing

   194   void print_on(outputStream* st) const;

   195   void print() const { print_on(tty); }

   196   bool equals(const OopMap* other) const;

   197 };

   198 

   199 

   200 class OopMapSet : public ResourceObj {

   201   friend class VMStructs;

   202  private:

   203   int _om_count;

   204   int _om_size;

   205   OopMap** _om_data;

   206 

   207   int om_count() const              { return _om_count; }

   208   void set_om_count(int value)      { _om_count = value; }

   209   void increment_count()            { _om_count++; }

   210   int om_size() const               { return _om_size; }

   211   void set_om_size(int value)       { _om_size = value; }

   212   OopMap** om_data() const          { return _om_data; }

   213   void set_om_data(OopMap** value)  { _om_data = value; }

   214   void grow_om_data();

   215   void set(int index,OopMap* value) { assert((index == 0) || ((index > 0) && (index < om_size())),"bad index"); _om_data[index] = value; }

   216 

   217  public:

   218   OopMapSet();

   219 

   220   // returns the number of OopMaps in this OopMapSet

   221   int size() const            { return _om_count; }

   222   // returns the OopMap at a given index

   223   OopMap* at(int index) const { assert((index >= 0) && (index <= om_count()),"bad index"); return _om_data[index]; }

   224 

   225   // Collect OopMaps.

   226   void add_gc_map(int pc, OopMap* map);

   227 

   228   // Returns the only oop map. Used for reconstructing

   229   // Adapter frames during deoptimization

   230   OopMap* singular_oop_map();

   231 

   232   // returns OopMap in that is anchored to the pc

   233   OopMap* find_map_at_offset(int pc_offset) const;

   234 

   235   int heap_size() const;

   236 

   237   // Methods oops_do() and all_do() filter out NULL oops and

   238   // oop == Universe::narrow_oop_base() before passing oops

   239   // to closures.

   240 

   241   // Iterates through frame for a compiled method

   242   static void oops_do            (const frame* fr,

   243                                   const RegisterMap* reg_map, OopClosure* f);

   244   static void update_register_map(const frame* fr, RegisterMap *reg_map);

   245 

   246   // Iterates through frame for a compiled method for dead ones and values, too

   247   static void all_do(const frame* fr, const RegisterMap* reg_map,

   248                      OopClosure* oop_fn,

   249                      void derived_oop_fn(oop* base, oop* derived),

   250                      OopClosure* value_fn);

   251 

   252   // Printing

   253   void print_on(outputStream* st) const;

   254   void print() const { print_on(tty); }

   255 };

   256 

   257 class ImmutableOopMapBuilder;

   258 

   259 class ImmutableOopMap {

   260   friend class OopMapStream;

   261   friend class VMStructs;

   262 #ifdef ASSERT

   263   friend class ImmutableOopMapBuilder;

   264 #endif

   265 private:

   266   int _count; // contains the number of entries in this OopMap

   267 

   268   address data_addr() const { return (address) this + sizeof(ImmutableOopMap); }

   269 public:

   270   ImmutableOopMap(const OopMap* oopmap);

   271 

   272   bool has_derived_pointer() const PRODUCT_RETURN0;

   273   int count() const { return _count; }

   274 #ifdef ASSERT

   275   int nr_of_bytes() const; // this is an expensive operation, only used in debug builds

   276 #endif

   277 

   278   // Printing

   279   void print_on(outputStream* st) const;

   280   void print() const { print_on(tty); }

   281 };

   282 

   283 class ImmutableOopMapSet;

   284 class ImmutableOopMap;

   285 class OopMapSet;

   286 

   287 class ImmutableOopMapPair {

   288   friend class VMStructs;

   289 private:

   290   int _pc_offset; // program counter offset from the beginning of the method

   291   int _oopmap_offset; // offset in the data in the ImmutableOopMapSet where the ImmutableOopMap is located

   292 public:

   293   ImmutableOopMapPair(int pc_offset, int oopmap_offset) : _pc_offset(pc_offset), _oopmap_offset(oopmap_offset) {

   294     assert(pc_offset >= 0 && oopmap_offset >= 0, "check");

   295   }

   296   const ImmutableOopMap* get_from(const ImmutableOopMapSet* set) const;

   297 

   298   int pc_offset() const { return _pc_offset; }

   299   int oopmap_offset() const { return _oopmap_offset; }

   300 };

   301 

   302 class ImmutableOopMapSet {

   303   friend class VMStructs;

   304 private:

   305   int _count; // nr of ImmutableOopMapPairs in the Set

   306   int _size; // nr of bytes including ImmutableOopMapSet itself

   307 

   308   address data() const { return (address) this + sizeof(*this) + sizeof(ImmutableOopMapPair) * _count; }

   309 

   310 public:

   311   ImmutableOopMapSet(const OopMapSet* oopmap_set, int size) : _count(oopmap_set->size()), _size(size) {}

   312 

   313   ImmutableOopMap* oopmap_at_offset(int offset) const {

   314     assert(offset >= 0 && offset < _size, "must be within boundaries");

   315     address addr = data() + offset;

   316     return (ImmutableOopMap*) addr;

   317   }

   318 

   319   ImmutableOopMapPair* get_pairs() const { return (ImmutableOopMapPair*) ((address) this + sizeof(*this)); }

   320 

   321   static ImmutableOopMapSet* build_from(const OopMapSet* oopmap_set);

   322 

   323   const ImmutableOopMap* find_map_at_offset(int pc_offset) const;

   324 

   325   const ImmutableOopMapPair* pair_at(int index) const { assert(index >= 0 && index < _count, "check"); return &get_pairs()[index]; }

   326 

   327   int count() const { return _count; }

   328   int nr_of_bytes() const { return _size; }

   329 

   330   void print_on(outputStream* st) const;

   331   void print() const { print_on(tty); }

   332 };

   333 

   334 class OopMapStream : public StackObj {

   335  private:

   336   CompressedReadStream* _stream;

   337   int _mask;

   338   int _size;

   339   int _position;

   340   bool _valid_omv;

   341   OopMapValue _omv;

   342   void find_next();

   343 

   344  public:

   345   OopMapStream(OopMap* oop_map, int oop_types_mask = OopMapValue::type_mask_in_place);

   346   OopMapStream(const ImmutableOopMap* oop_map, int oop_types_mask = OopMapValue::type_mask_in_place);

   347   bool is_done()                        { if(!_valid_omv) { find_next(); } return !_valid_omv; }

   348   void next()                           { find_next(); }

   349   OopMapValue current()                 { return _omv; }

   350 #ifdef ASSERT

   351   int stream_position() const           { return _stream->position(); }

   352 #endif

   353 };

   354 

   355 class ImmutableOopMapBuilder {

   356 private:

   357   class Mapping;

   358 

   359 private:

   360   const OopMapSet* _set;

   361   const OopMap* _empty;

   362   const OopMap* _last;

   363   int _empty_offset;

   364   int _last_offset;

   365   int _offset;

   366   int _required;

   367   Mapping* _mapping;

   368   ImmutableOopMapSet* _new_set;

   369 

   370   /* Used for bookkeeping when building ImmutableOopMaps */

   371   class Mapping : public ResourceObj {

   372   public:

   373     enum kind_t { OOPMAP_UNKNOWN = 0, OOPMAP_NEW = 1, OOPMAP_EMPTY = 2, OOPMAP_DUPLICATE = 3 };

   374 

   375     kind_t _kind;

   376     int _offset;

   377     int _size;

   378     const OopMap* _map;

   379     const OopMap* _other;

   380 

   381     Mapping() : _kind(OOPMAP_UNKNOWN), _offset(-1), _size(-1), _map(NULL) {}

   382 

   383     void set(kind_t kind, int offset, int size, const OopMap* map = 0, const OopMap* other = 0) {

   384       _kind = kind;

   385       _offset = offset;

   386       _size = size;

   387       _map = map;

   388       _other = other;

   389     }

   390   };

   391 

   392 public:

   393   ImmutableOopMapBuilder(const OopMapSet* set);

   394 

   395   int heap_size();

   396   ImmutableOopMapSet* build();

   397   ImmutableOopMapSet* generate_into(address buffer);

   398 private:

   399   bool is_empty(const OopMap* map) const {

   400     return map->count() == 0;

   401   }

   402 

   403   bool is_last_duplicate(const OopMap* map) {

   404     if (_last != NULL && _last->count() > 0 && _last->equals(map)) {

   405       return true;

   406     }

   407     return false;

   408   }

   409 

   410 #ifdef ASSERT

   411   void verify(address buffer, int size, const ImmutableOopMapSet* set);

   412 #endif

   413 

   414   bool has_empty() const {

   415     return _empty_offset != -1;

   416   }

   417 

   418   int size_for(const OopMap* map) const;

   419   void fill_pair(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set);

   420   int fill_map(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set);

   421   void fill(ImmutableOopMapSet* set, int size);

   422 };

   423 

   424 

   425 // Derived pointer support. This table keeps track of all derived points on a

   426 // stack.  It is cleared before each scavenge/GC.  During the traversal of all

   427 // oops, it is filled in with references to all locations that contains a

   428 // derived oop (assumed to be very few).  When the GC is complete, the derived

   429 // pointers are updated based on their base pointers new value and an offset.

   430 #if defined(COMPILER2) || INCLUDE_JVMCI

   431 class DerivedPointerTable : public AllStatic {

   432   friend class VMStructs;

   433  private:

   434    static GrowableArray<DerivedPointerEntry*>* _list;

   435    static bool _active;                      // do not record pointers for verify pass etc.

   436  public:

   437   static void clear();                       // Called before scavenge/GC

   438   static void add(oop *derived, oop *base);  // Called during scavenge/GC

   439   static void update_pointers();             // Called after  scavenge/GC

   440   static bool is_empty()                     { return _list == NULL || _list->is_empty(); }

   441   static bool is_active()                    { return _active; }

   442   static void set_active(bool value)         { _active = value; }

   443 };

   444 

   445 // A utility class to temporarily "deactivate" the DerivedPointerTable.

   446 // (Note: clients are responsible for any MT-safety issues)

   447 class DerivedPointerTableDeactivate: public StackObj {

   448  private:

   449   bool _active;

   450  public:

   451   DerivedPointerTableDeactivate() {

   452     _active = DerivedPointerTable::is_active();

   453     if (_active) {

   454       DerivedPointerTable::set_active(false);

   455     }

   456   }

   457 

   458   ~DerivedPointerTableDeactivate() {

   459     assert(!DerivedPointerTable::is_active(),

   460            "Inconsistency: not MT-safe");

   461     if (_active) {

   462       DerivedPointerTable::set_active(true);

   463     }

   464   }

   465 };

   466 #endif // COMPILER2 || INCLUDE_JVMCI

   467 

   468 #endif // SHARE_VM_COMPILER_OOPMAP_HPP