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 /*

  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.

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

  *

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

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

  * published by the Free Software Foundation.

  *

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

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

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

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

  * accompanied this code).

  *

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

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

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

  *

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

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

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  */

 #include "precompiled.hpp"

 #include "interpreter/oopMapCache.hpp"

 #include "memory/allocation.inline.hpp"

 #include "memory/resourceArea.hpp"

 #include "oops/oop.inline.hpp"

 #include "prims/jvmtiRedefineClassesTrace.hpp"

 #include "runtime/handles.inline.hpp"

 #include "runtime/signature.hpp"

 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC

 class OopMapCacheEntry: private InterpreterOopMap {

   friend class InterpreterOopMap;

   friend class OopMapForCacheEntry;

   friend class OopMapCache;

   friend class VerifyClosure;

  protected:

   // Initialization

   void fill(methodHandle method, int bci);

   // fills the bit mask for native calls

   void fill_for_native(methodHandle method);

   void set_mask(CellTypeState* vars, CellTypeState* stack, int stack_top);

   // Deallocate bit masks and initialize fields

   void flush();

  private:

   void allocate_bit_mask();   // allocates the bit mask on C heap f necessary

   void deallocate_bit_mask(); // allocates the bit mask on C heap f necessary

   bool verify_mask(CellTypeState *vars, CellTypeState *stack, int max_locals, int stack_top);

  public:

   OopMapCacheEntry() : InterpreterOopMap() {

 #ifdef ASSERT

      _resource_allocate_bit_mask = false;

 #endif

   }

 };

 // Implementation of OopMapForCacheEntry

 // (subclass of GenerateOopMap, initializes an OopMapCacheEntry for a given method and bci)

 class OopMapForCacheEntry: public GenerateOopMap {

   OopMapCacheEntry *_entry;

   int               _bci;

   int               _stack_top;

   virtual bool report_results() const     { return false; }

   virtual bool possible_gc_point          (BytecodeStream *bcs);

   virtual void fill_stackmap_prolog       (int nof_gc_points);

   virtual void fill_stackmap_epilog       ();

   virtual void fill_stackmap_for_opcodes  (BytecodeStream *bcs,

                                            CellTypeState* vars,

                                            CellTypeState* stack,

                                            int stack_top);

   virtual void fill_init_vars             (GrowableArray<intptr_t> *init_vars);

  public:

   OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry *entry);

   // Computes stack map for (method,bci) and initialize entry

   void compute_map(TRAPS);

   int  size();

 };

 OopMapForCacheEntry::OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry* entry) : GenerateOopMap(method) {

   _bci       = bci;

   _entry     = entry;

   _stack_top = -1;

 }

 void OopMapForCacheEntry::compute_map(TRAPS) {

   assert(!method()->is_native(), "cannot compute oop map for native methods");

   // First check if it is a method where the stackmap is always empty

   if (method()->code_size() == 0 || method()->max_locals() + method()->max_stack() == 0) {

     _entry->set_mask_size(0);

   } else {

     ResourceMark rm;

     GenerateOopMap::compute_map(CATCH);

     result_for_basicblock(_bci);

   }

 }

 bool OopMapForCacheEntry::possible_gc_point(BytecodeStream *bcs) {

   return false; // We are not reporting any result. We call result_for_basicblock directly

 }

 void OopMapForCacheEntry::fill_stackmap_prolog(int nof_gc_points) {

   // Do nothing

 }

 void OopMapForCacheEntry::fill_stackmap_epilog() {

   // Do nothing

 }

 void OopMapForCacheEntry::fill_init_vars(GrowableArray<intptr_t> *init_vars) {

   // Do nothing

 }

 void OopMapForCacheEntry::fill_stackmap_for_opcodes(BytecodeStream *bcs,

                                                     CellTypeState* vars,

                                                     CellTypeState* stack,

                                                     int stack_top) {

   // Only interested in one specific bci

   if (bcs->bci() == _bci) {

     _entry->set_mask(vars, stack, stack_top);

     _stack_top = stack_top;

   }

 }

 int OopMapForCacheEntry::size() {

   assert(_stack_top != -1, "compute_map must be called first");

   return ((method()->is_static()) ? 0 : 1) + method()->max_locals() + _stack_top;

 }

 // Implementation of InterpreterOopMap and OopMapCacheEntry

 class VerifyClosure : public OffsetClosure {

  private:

   OopMapCacheEntry* _entry;

   bool              _failed;

  public:

   VerifyClosure(OopMapCacheEntry* entry)         { _entry = entry; _failed = false; }

   void offset_do(int offset)                     { if (!_entry->is_oop(offset)) _failed = true; }

   bool failed() const                            { return _failed; }

 };

 InterpreterOopMap::InterpreterOopMap() {

   initialize();

 #ifdef ASSERT

   _resource_allocate_bit_mask = true;

 #endif

 }

 InterpreterOopMap::~InterpreterOopMap() {

   // The expection is that the bit mask was allocated

   // last in this resource area.  That would make the free of the

   // bit_mask effective (see how FREE_RESOURCE_ARRAY does a free).

   // If it was not allocated last, there is not a correctness problem

   // but the space for the bit_mask is not freed.

   assert(_resource_allocate_bit_mask, "Trying to free C heap space");

   if (mask_size() > small_mask_limit) {

     FREE_RESOURCE_ARRAY(uintptr_t, _bit_mask[0], mask_word_size());

   }

 }

 bool InterpreterOopMap::is_empty() {

   bool result = _method == NULL;

   assert(_method != NULL || (_bci == 0 &&

     (_mask_size == 0 || _mask_size == USHRT_MAX) &&

     _bit_mask[0] == 0), "Should be completely empty");

   return result;

 }

 void InterpreterOopMap::initialize() {

   _method    = NULL;

   _mask_size = USHRT_MAX;  // This value should cause a failure quickly

   _bci       = 0;

   _expression_stack_size = 0;

   for (int i = 0; i < N; i++) _bit_mask[i] = 0;

 }

 void InterpreterOopMap::iterate_oop(OffsetClosure* oop_closure) {

   int n = number_of_entries();

   int word_index = 0;

   uintptr_t value = 0;

   uintptr_t mask = 0;

   // iterate over entries

   for (int i = 0; i < n; i++, mask <<= bits_per_entry) {

     // get current word

     if (mask == 0) {

       value = bit_mask()[word_index++];

       mask = 1;

     }

     // test for oop

     if ((value & (mask << oop_bit_number)) != 0) oop_closure->offset_do(i);

   }

 }

 #ifdef ENABLE_ZAP_DEAD_LOCALS

 void InterpreterOopMap::iterate_all(OffsetClosure* oop_closure, OffsetClosure* value_closure, OffsetClosure* dead_closure) {

   int n = number_of_entries();

   int word_index = 0;

   uintptr_t value = 0;

   uintptr_t mask = 0;

   // iterate over entries

   for (int i = 0; i < n; i++, mask <<= bits_per_entry) {

     // get current word

     if (mask == 0) {

       value = bit_mask()[word_index++];

       mask = 1;

     }

     // test for dead values  & oops, and for live values

          if ((value & (mask << dead_bit_number)) != 0)  dead_closure->offset_do(i); // call this for all dead values or oops

     else if ((value & (mask <<  oop_bit_number)) != 0)   oop_closure->offset_do(i); // call this for all live oops

     else                                               value_closure->offset_do(i); // call this for all live values

   }

 }

 #endif

 void InterpreterOopMap::print() {

   int n = number_of_entries();

   tty->print("oop map for ");

   method()->print_value();

   tty->print(" @ %d = [%d] { ", bci(), n);

   for (int i = 0; i < n; i++) {

 #ifdef ENABLE_ZAP_DEAD_LOCALS

     if (is_dead(i)) tty->print("%d+ ", i);

     else

 #endif

     if (is_oop(i)) tty->print("%d ", i);

   }

   tty->print_cr("}");

 }

 class MaskFillerForNative: public NativeSignatureIterator {

  private:

   uintptr_t * _mask;                             // the bit mask to be filled

   int         _size;                             // the mask size in bits

   void set_one(int i) {

     i *= InterpreterOopMap::bits_per_entry;

     assert(0 <= i && i < _size, "offset out of bounds");

     _mask[i / BitsPerWord] |= (((uintptr_t) 1 << InterpreterOopMap::oop_bit_number) << (i % BitsPerWord));

   }

  public:

   void pass_int()                                { /* ignore */ }

   void pass_long()                               { /* ignore */ }

   void pass_float()                              { /* ignore */ }

   void pass_double()                             { /* ignore */ }

   void pass_object()                             { set_one(offset()); }

   MaskFillerForNative(methodHandle method, uintptr_t* mask, int size) : NativeSignatureIterator(method) {

     _mask   = mask;

     _size   = size;

     // initialize with 0

     int i = (size + BitsPerWord - 1) / BitsPerWord;

     while (i-- > 0) _mask[i] = 0;

   }

   void generate() {

     NativeSignatureIterator::iterate();

   }

 };

 bool OopMapCacheEntry::verify_mask(CellTypeState* vars, CellTypeState* stack, int max_locals, int stack_top) {

   // Check mask includes map

   VerifyClosure blk(this);

   iterate_oop(&blk);

   if (blk.failed()) return false;

   // Check if map is generated correctly

   // (Use ?: operator to make sure all 'true' & 'false' are represented exactly the same so we can use == afterwards)

   if (TraceOopMapGeneration && Verbose) tty->print("Locals (%d): ", max_locals);

   for(int i = 0; i < max_locals; i++) {

     bool v1 = is_oop(i)               ? true : false;

     bool v2 = vars[i].is_reference()  ? true : false;

     assert(v1 == v2, "locals oop mask generation error");

     if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);

 #ifdef ENABLE_ZAP_DEAD_LOCALS

     bool v3 = is_dead(i)              ? true : false;

     bool v4 = !vars[i].is_live()      ? true : false;

     assert(v3 == v4, "locals live mask generation error");

     assert(!(v1 && v3), "dead value marked as oop");

 #endif

   }

   if (TraceOopMapGeneration && Verbose) { tty->cr(); tty->print("Stack (%d): ", stack_top); }

   for(int j = 0; j < stack_top; j++) {

     bool v1 = is_oop(max_locals + j)  ? true : false;

     bool v2 = stack[j].is_reference() ? true : false;

     assert(v1 == v2, "stack oop mask generation error");

     if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);

 #ifdef ENABLE_ZAP_DEAD_LOCALS

     bool v3 = is_dead(max_locals + j) ? true : false;

     bool v4 = !stack[j].is_live()     ? true : false;

     assert(v3 == v4, "stack live mask generation error");

     assert(!(v1 && v3), "dead value marked as oop");

 #endif

   }

   if (TraceOopMapGeneration && Verbose) tty->cr();

   return true;

 }

 void OopMapCacheEntry::allocate_bit_mask() {

   if (mask_size() > small_mask_limit) {

     assert(_bit_mask[0] == 0, "bit mask should be new or just flushed");

     _bit_mask[0] = (intptr_t)

       NEW_C_HEAP_ARRAY(uintptr_t, mask_word_size(), mtClass);

   }

 }

 void OopMapCacheEntry::deallocate_bit_mask() {

   if (mask_size() > small_mask_limit && _bit_mask[0] != 0) {

     assert(!Thread::current()->resource_area()->contains((void*)_bit_mask[0]),

       "This bit mask should not be in the resource area");

     FREE_C_HEAP_ARRAY(uintptr_t, _bit_mask[0], mtClass);

     debug_only(_bit_mask[0] = 0;)

   }

 }

 void OopMapCacheEntry::fill_for_native(methodHandle mh) {

   assert(mh->is_native(), "method must be native method");

   set_mask_size(mh->size_of_parameters() * bits_per_entry);

   allocate_bit_mask();

   // fill mask for parameters

   MaskFillerForNative mf(mh, bit_mask(), mask_size());

   mf.generate();

 }

 void OopMapCacheEntry::fill(methodHandle method, int bci) {

   HandleMark hm;

   // Flush entry to deallocate an existing entry

   flush();

   set_method(method());

   set_bci(bci);

   if (method->is_native()) {

     // Native method activations have oops only among the parameters and one

     // extra oop following the parameters (the mirror for static native methods).

     fill_for_native(method);

   } else {

     EXCEPTION_MARK;

     OopMapForCacheEntry gen(method, bci, this);

     gen.compute_map(CATCH);

   }

 }

 void OopMapCacheEntry::set_mask(CellTypeState *vars, CellTypeState *stack, int stack_top) {

   // compute bit mask size

   int max_locals = method()->max_locals();

   int n_entries = max_locals + stack_top;

   set_mask_size(n_entries * bits_per_entry);

   allocate_bit_mask();

   set_expression_stack_size(stack_top);

   // compute bits

   int word_index = 0;

   uintptr_t value = 0;

   uintptr_t mask = 1;

   CellTypeState* cell = vars;

   for (int entry_index = 0; entry_index < n_entries; entry_index++, mask <<= bits_per_entry, cell++) {

     // store last word

     if (mask == 0) {

       bit_mask()[word_index++] = value;

       value = 0;

       mask = 1;

     }

     // switch to stack when done with locals

     if (entry_index == max_locals) {

       cell = stack;

     }

     // set oop bit

     if ( cell->is_reference()) {

       value |= (mask << oop_bit_number );

     }

   #ifdef ENABLE_ZAP_DEAD_LOCALS

     // set dead bit

     if (!cell->is_live()) {

       value |= (mask << dead_bit_number);

       assert(!cell->is_reference(), "dead value marked as oop");

     }

   #endif

   }

   // make sure last word is stored

   bit_mask()[word_index] = value;

   // verify bit mask

   assert(verify_mask(vars, stack, max_locals, stack_top), "mask could not be verified");

 }

 void OopMapCacheEntry::flush() {

   deallocate_bit_mask();

   initialize();

 }

 // Implementation of OopMapCache

 #ifndef PRODUCT

 static long _total_memory_usage = 0;

 long OopMapCache::memory_usage() {

   return _total_memory_usage;

 }

 #endif

 void InterpreterOopMap::resource_copy(OopMapCacheEntry* from) {

   assert(_resource_allocate_bit_mask,

     "Should not resource allocate the _bit_mask");

   set_method(from->method());

   set_bci(from->bci());

   set_mask_size(from->mask_size());

   set_expression_stack_size(from->expression_stack_size());

   // Is the bit mask contained in the entry?

   if (from->mask_size() <= small_mask_limit) {

     memcpy((void *)_bit_mask, (void *)from->_bit_mask,

       mask_word_size() * BytesPerWord);

   } else {

     // The expectation is that this InterpreterOopMap is a recently created

     // and empty. It is used to get a copy of a cached entry.

     // If the bit mask has a value, it should be in the

     // resource area.

     assert(_bit_mask[0] == 0 ||

       Thread::current()->resource_area()->contains((void*)_bit_mask[0]),

       "The bit mask should have been allocated from a resource area");

     // Allocate the bit_mask from a Resource area for performance.  Allocating

     // from the C heap as is done for OopMapCache has a significant

     // performance impact.

     _bit_mask[0] = (uintptr_t) NEW_RESOURCE_ARRAY(uintptr_t, mask_word_size());

     assert(_bit_mask[0] != 0, "bit mask was not allocated");

     memcpy((void*) _bit_mask[0], (void*) from->_bit_mask[0],

       mask_word_size() * BytesPerWord);

   }

 }

 inline unsigned int OopMapCache::hash_value_for(methodHandle method, int bci) {

   // We use method->code_size() rather than method->identity_hash() below since

   // the mark may not be present if a pointer to the method is already reversed.

   return   ((unsigned int) bci)

          ^ ((unsigned int) method->max_locals()         << 2)

          ^ ((unsigned int) method->code_size()          << 4)

          ^ ((unsigned int) method->size_of_parameters() << 6);

 }

 OopMapCache::OopMapCache() :

   _mut(Mutex::leaf, "An OopMapCache lock", true)

 {

   _array  = NEW_C_HEAP_ARRAY(OopMapCacheEntry, _size, mtClass);

   // Cannot call flush for initialization, since flush

   // will check if memory should be deallocated

   for(int i = 0; i < _size; i++) _array[i].initialize();

   NOT_PRODUCT(_total_memory_usage += sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)

 }

 OopMapCache::~OopMapCache() {

   assert(_array != NULL, "sanity check");

   // Deallocate oop maps that are allocated out-of-line

   flush();

   // Deallocate array

   NOT_PRODUCT(_total_memory_usage -= sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)

   FREE_C_HEAP_ARRAY(OopMapCacheEntry, _array, mtClass);

 }

 OopMapCacheEntry* OopMapCache::entry_at(int i) const {

   return &_array[i % _size];

 }

 void OopMapCache::flush() {

   for (int i = 0; i < _size; i++) _array[i].flush();

 }

 void OopMapCache::flush_obsolete_entries() {

   for (int i = 0; i < _size; i++)

     if (!_array[i].is_empty() && _array[i].method()->is_old()) {

       // Cache entry is occupied by an old redefined method and we don't want

       // to pin it down so flush the entry.

       RC_TRACE(0x08000000, ("flush: %s(%s): cached entry @%d",

         _array[i].method()->name()->as_C_string(),

         _array[i].method()->signature()->as_C_string(), i));

       _array[i].flush();

     }

 }

 void OopMapCache::lookup(methodHandle method,

                          int bci,

                          InterpreterOopMap* entry_for) {

   MutexLocker x(&_mut);

   OopMapCacheEntry* entry = NULL;

   int probe = hash_value_for(method, bci);

   // Search hashtable for match

   int i;

   for(i = 0; i < _probe_depth; i++) {

     entry = entry_at(probe + i);

     if (entry->match(method, bci)) {

       entry_for->resource_copy(entry);

       assert(!entry_for->is_empty(), "A non-empty oop map should be returned");

       return;

     }

   }

   if (TraceOopMapGeneration) {

     static int count = 0;

     ResourceMark rm;

     tty->print("%d - Computing oopmap at bci %d for ", ++count, bci);

     method->print_value(); tty->cr();

   }

   // Entry is not in hashtable.

   // Compute entry and return it

   if (method->should_not_be_cached()) {

     // It is either not safe or not a good idea to cache this Method*

     // at this time. We give the caller of lookup() a copy of the

     // interesting info via parameter entry_for, but we don't add it to

     // the cache. See the gory details in Method*.cpp.

     compute_one_oop_map(method, bci, entry_for);

     return;

   }

   // First search for an empty slot

   for(i = 0; i < _probe_depth; i++) {

     entry  = entry_at(probe + i);

     if (entry->is_empty()) {

       entry->fill(method, bci);

       entry_for->resource_copy(entry);

       assert(!entry_for->is_empty(), "A non-empty oop map should be returned");

       return;

     }

   }

   if (TraceOopMapGeneration) {

     ResourceMark rm;

     tty->print_cr("*** collision in oopmap cache - flushing item ***");

   }

   // No empty slot (uncommon case). Use (some approximation of a) LRU algorithm

   //entry_at(probe + _probe_depth - 1)->flush();

   //for(i = _probe_depth - 1; i > 0; i--) {

   //  // Coping entry[i] = entry[i-1];

   //  OopMapCacheEntry *to   = entry_at(probe + i);

   //  OopMapCacheEntry *from = entry_at(probe + i - 1);

   //  to->copy(from);

   // }

   assert(method->is_method(), "gaga");

   entry = entry_at(probe + 0);

   entry->fill(method, bci);

   // Copy the  newly cached entry to input parameter

   entry_for->resource_copy(entry);

   if (TraceOopMapGeneration) {

     ResourceMark rm;

     tty->print("Done with ");

     method->print_value(); tty->cr();

   }

   assert(!entry_for->is_empty(), "A non-empty oop map should be returned");

   return;

 }

 void OopMapCache::compute_one_oop_map(methodHandle method, int bci, InterpreterOopMap* entry) {

   // Due to the invariants above it's tricky to allocate a temporary OopMapCacheEntry on the stack

   OopMapCacheEntry* tmp = NEW_C_HEAP_ARRAY(OopMapCacheEntry, 1, mtClass);

   tmp->initialize();

   tmp->fill(method, bci);

   entry->resource_copy(tmp);

   FREE_C_HEAP_ARRAY(OopMapCacheEntry, tmp, mtInternal);

 }