aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #include "precompiled.hpp"
aoqi@0: #include "interpreter/oopMapCache.hpp"
aoqi@0: #include "memory/allocation.inline.hpp"
aoqi@0: #include "memory/resourceArea.hpp"
aoqi@0: #include "oops/oop.inline.hpp"
aoqi@0: #include "prims/jvmtiRedefineClassesTrace.hpp"
aoqi@0: #include "runtime/handles.inline.hpp"
aoqi@0: #include "runtime/signature.hpp"
aoqi@0: 
aoqi@0: PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
aoqi@0: 
aoqi@0: class OopMapCacheEntry: private InterpreterOopMap {
aoqi@0:   friend class InterpreterOopMap;
aoqi@0:   friend class OopMapForCacheEntry;
aoqi@0:   friend class OopMapCache;
aoqi@0:   friend class VerifyClosure;
aoqi@0: 
aoqi@0:  protected:
aoqi@0:   // Initialization
aoqi@0:   void fill(methodHandle method, int bci);
aoqi@0:   // fills the bit mask for native calls
aoqi@0:   void fill_for_native(methodHandle method);
aoqi@0:   void set_mask(CellTypeState* vars, CellTypeState* stack, int stack_top);
aoqi@0: 
aoqi@0:   // Deallocate bit masks and initialize fields
aoqi@0:   void flush();
aoqi@0: 
aoqi@0:  private:
aoqi@0:   void allocate_bit_mask();   // allocates the bit mask on C heap f necessary
aoqi@0:   void deallocate_bit_mask(); // allocates the bit mask on C heap f necessary
aoqi@0:   bool verify_mask(CellTypeState *vars, CellTypeState *stack, int max_locals, int stack_top);
aoqi@0: 
aoqi@0:  public:
aoqi@0:   OopMapCacheEntry() : InterpreterOopMap() {
aoqi@0: #ifdef ASSERT
aoqi@0:      _resource_allocate_bit_mask = false;
aoqi@0: #endif
aoqi@0:   }
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: // Implementation of OopMapForCacheEntry
aoqi@0: // (subclass of GenerateOopMap, initializes an OopMapCacheEntry for a given method and bci)
aoqi@0: 
aoqi@0: class OopMapForCacheEntry: public GenerateOopMap {
aoqi@0:   OopMapCacheEntry *_entry;
aoqi@0:   int               _bci;
aoqi@0:   int               _stack_top;
aoqi@0: 
aoqi@0:   virtual bool report_results() const     { return false; }
aoqi@0:   virtual bool possible_gc_point          (BytecodeStream *bcs);
aoqi@0:   virtual void fill_stackmap_prolog       (int nof_gc_points);
aoqi@0:   virtual void fill_stackmap_epilog       ();
aoqi@0:   virtual void fill_stackmap_for_opcodes  (BytecodeStream *bcs,
aoqi@0:                                            CellTypeState* vars,
aoqi@0:                                            CellTypeState* stack,
aoqi@0:                                            int stack_top);
aoqi@0:   virtual void fill_init_vars             (GrowableArray<intptr_t> *init_vars);
aoqi@0: 
aoqi@0:  public:
aoqi@0:   OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry *entry);
aoqi@0: 
aoqi@0:   // Computes stack map for (method,bci) and initialize entry
aoqi@0:   void compute_map(TRAPS);
aoqi@0:   int  size();
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: OopMapForCacheEntry::OopMapForCacheEntry(methodHandle method, int bci, OopMapCacheEntry* entry) : GenerateOopMap(method) {
aoqi@0:   _bci       = bci;
aoqi@0:   _entry     = entry;
aoqi@0:   _stack_top = -1;
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void OopMapForCacheEntry::compute_map(TRAPS) {
aoqi@0:   assert(!method()->is_native(), "cannot compute oop map for native methods");
aoqi@0:   // First check if it is a method where the stackmap is always empty
aoqi@0:   if (method()->code_size() == 0 || method()->max_locals() + method()->max_stack() == 0) {
aoqi@0:     _entry->set_mask_size(0);
aoqi@0:   } else {
aoqi@0:     ResourceMark rm;
aoqi@0:     GenerateOopMap::compute_map(CATCH);
aoqi@0:     result_for_basicblock(_bci);
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: bool OopMapForCacheEntry::possible_gc_point(BytecodeStream *bcs) {
aoqi@0:   return false; // We are not reporting any result. We call result_for_basicblock directly
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void OopMapForCacheEntry::fill_stackmap_prolog(int nof_gc_points) {
aoqi@0:   // Do nothing
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void OopMapForCacheEntry::fill_stackmap_epilog() {
aoqi@0:   // Do nothing
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void OopMapForCacheEntry::fill_init_vars(GrowableArray<intptr_t> *init_vars) {
aoqi@0:   // Do nothing
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void OopMapForCacheEntry::fill_stackmap_for_opcodes(BytecodeStream *bcs,
aoqi@0:                                                     CellTypeState* vars,
aoqi@0:                                                     CellTypeState* stack,
aoqi@0:                                                     int stack_top) {
aoqi@0:   // Only interested in one specific bci
aoqi@0:   if (bcs->bci() == _bci) {
aoqi@0:     _entry->set_mask(vars, stack, stack_top);
aoqi@0:     _stack_top = stack_top;
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: int OopMapForCacheEntry::size() {
aoqi@0:   assert(_stack_top != -1, "compute_map must be called first");
aoqi@0:   return ((method()->is_static()) ? 0 : 1) + method()->max_locals() + _stack_top;
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: // Implementation of InterpreterOopMap and OopMapCacheEntry
aoqi@0: 
aoqi@0: class VerifyClosure : public OffsetClosure {
aoqi@0:  private:
aoqi@0:   OopMapCacheEntry* _entry;
aoqi@0:   bool              _failed;
aoqi@0: 
aoqi@0:  public:
aoqi@0:   VerifyClosure(OopMapCacheEntry* entry)         { _entry = entry; _failed = false; }
aoqi@0:   void offset_do(int offset)                     { if (!_entry->is_oop(offset)) _failed = true; }
aoqi@0:   bool failed() const                            { return _failed; }
aoqi@0: };
aoqi@0: 
aoqi@0: InterpreterOopMap::InterpreterOopMap() {
aoqi@0:   initialize();
aoqi@0: #ifdef ASSERT
aoqi@0:   _resource_allocate_bit_mask = true;
aoqi@0: #endif
aoqi@0: }
aoqi@0: 
aoqi@0: InterpreterOopMap::~InterpreterOopMap() {
aoqi@0:   // The expection is that the bit mask was allocated
aoqi@0:   // last in this resource area.  That would make the free of the
aoqi@0:   // bit_mask effective (see how FREE_RESOURCE_ARRAY does a free).
aoqi@0:   // If it was not allocated last, there is not a correctness problem
aoqi@0:   // but the space for the bit_mask is not freed.
aoqi@0:   assert(_resource_allocate_bit_mask, "Trying to free C heap space");
aoqi@0:   if (mask_size() > small_mask_limit) {
aoqi@0:     FREE_RESOURCE_ARRAY(uintptr_t, _bit_mask[0], mask_word_size());
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: bool InterpreterOopMap::is_empty() {
aoqi@0:   bool result = _method == NULL;
aoqi@0:   assert(_method != NULL || (_bci == 0 &&
aoqi@0:     (_mask_size == 0 || _mask_size == USHRT_MAX) &&
aoqi@0:     _bit_mask[0] == 0), "Should be completely empty");
aoqi@0:   return result;
aoqi@0: }
aoqi@0: 
aoqi@0: void InterpreterOopMap::initialize() {
aoqi@0:   _method    = NULL;
aoqi@0:   _mask_size = USHRT_MAX;  // This value should cause a failure quickly
aoqi@0:   _bci       = 0;
aoqi@0:   _expression_stack_size = 0;
aoqi@0:   for (int i = 0; i < N; i++) _bit_mask[i] = 0;
aoqi@0: }
aoqi@0: 
aoqi@0: void InterpreterOopMap::iterate_oop(OffsetClosure* oop_closure) {
aoqi@0:   int n = number_of_entries();
aoqi@0:   int word_index = 0;
aoqi@0:   uintptr_t value = 0;
aoqi@0:   uintptr_t mask = 0;
aoqi@0:   // iterate over entries
aoqi@0:   for (int i = 0; i < n; i++, mask <<= bits_per_entry) {
aoqi@0:     // get current word
aoqi@0:     if (mask == 0) {
aoqi@0:       value = bit_mask()[word_index++];
aoqi@0:       mask = 1;
aoqi@0:     }
aoqi@0:     // test for oop
aoqi@0:     if ((value & (mask << oop_bit_number)) != 0) oop_closure->offset_do(i);
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: #ifdef ENABLE_ZAP_DEAD_LOCALS
aoqi@0: 
aoqi@0: void InterpreterOopMap::iterate_all(OffsetClosure* oop_closure, OffsetClosure* value_closure, OffsetClosure* dead_closure) {
aoqi@0:   int n = number_of_entries();
aoqi@0:   int word_index = 0;
aoqi@0:   uintptr_t value = 0;
aoqi@0:   uintptr_t mask = 0;
aoqi@0:   // iterate over entries
aoqi@0:   for (int i = 0; i < n; i++, mask <<= bits_per_entry) {
aoqi@0:     // get current word
aoqi@0:     if (mask == 0) {
aoqi@0:       value = bit_mask()[word_index++];
aoqi@0:       mask = 1;
aoqi@0:     }
aoqi@0:     // test for dead values  & oops, and for live values
aoqi@0:          if ((value & (mask << dead_bit_number)) != 0)  dead_closure->offset_do(i); // call this for all dead values or oops
aoqi@0:     else if ((value & (mask <<  oop_bit_number)) != 0)   oop_closure->offset_do(i); // call this for all live oops
aoqi@0:     else                                               value_closure->offset_do(i); // call this for all live values
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: #endif
aoqi@0: 
aoqi@0: 
aoqi@0: void InterpreterOopMap::print() {
aoqi@0:   int n = number_of_entries();
aoqi@0:   tty->print("oop map for ");
aoqi@0:   method()->print_value();
aoqi@0:   tty->print(" @ %d = [%d] { ", bci(), n);
aoqi@0:   for (int i = 0; i < n; i++) {
aoqi@0: #ifdef ENABLE_ZAP_DEAD_LOCALS
aoqi@0:     if (is_dead(i)) tty->print("%d+ ", i);
aoqi@0:     else
aoqi@0: #endif
aoqi@0:     if (is_oop(i)) tty->print("%d ", i);
aoqi@0:   }
aoqi@0:   tty->print_cr("}");
aoqi@0: }
aoqi@0: 
aoqi@0: class MaskFillerForNative: public NativeSignatureIterator {
aoqi@0:  private:
aoqi@0:   uintptr_t * _mask;                             // the bit mask to be filled
aoqi@0:   int         _size;                             // the mask size in bits
aoqi@0: 
aoqi@0:   void set_one(int i) {
aoqi@0:     i *= InterpreterOopMap::bits_per_entry;
aoqi@0:     assert(0 <= i && i < _size, "offset out of bounds");
aoqi@0:     _mask[i / BitsPerWord] |= (((uintptr_t) 1 << InterpreterOopMap::oop_bit_number) << (i % BitsPerWord));
aoqi@0:   }
aoqi@0: 
aoqi@0:  public:
aoqi@0:   void pass_int()                                { /* ignore */ }
aoqi@0:   void pass_long()                               { /* ignore */ }
aoqi@0:   void pass_float()                              { /* ignore */ }
aoqi@0:   void pass_double()                             { /* ignore */ }
aoqi@0:   void pass_object()                             { set_one(offset()); }
aoqi@0: 
aoqi@0:   MaskFillerForNative(methodHandle method, uintptr_t* mask, int size) : NativeSignatureIterator(method) {
aoqi@0:     _mask   = mask;
aoqi@0:     _size   = size;
aoqi@0:     // initialize with 0
aoqi@0:     int i = (size + BitsPerWord - 1) / BitsPerWord;
aoqi@0:     while (i-- > 0) _mask[i] = 0;
aoqi@0:   }
aoqi@0: 
aoqi@0:   void generate() {
aoqi@0:     NativeSignatureIterator::iterate();
aoqi@0:   }
aoqi@0: };
aoqi@0: 
aoqi@0: bool OopMapCacheEntry::verify_mask(CellTypeState* vars, CellTypeState* stack, int max_locals, int stack_top) {
aoqi@0:   // Check mask includes map
aoqi@0:   VerifyClosure blk(this);
aoqi@0:   iterate_oop(&blk);
aoqi@0:   if (blk.failed()) return false;
aoqi@0: 
aoqi@0:   // Check if map is generated correctly
aoqi@0:   // (Use ?: operator to make sure all 'true' & 'false' are represented exactly the same so we can use == afterwards)
aoqi@0:   if (TraceOopMapGeneration && Verbose) tty->print("Locals (%d): ", max_locals);
aoqi@0: 
aoqi@0:   for(int i = 0; i < max_locals; i++) {
aoqi@0:     bool v1 = is_oop(i)               ? true : false;
aoqi@0:     bool v2 = vars[i].is_reference()  ? true : false;
aoqi@0:     assert(v1 == v2, "locals oop mask generation error");
aoqi@0:     if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
aoqi@0: #ifdef ENABLE_ZAP_DEAD_LOCALS
aoqi@0:     bool v3 = is_dead(i)              ? true : false;
aoqi@0:     bool v4 = !vars[i].is_live()      ? true : false;
aoqi@0:     assert(v3 == v4, "locals live mask generation error");
aoqi@0:     assert(!(v1 && v3), "dead value marked as oop");
aoqi@0: #endif
aoqi@0:   }
aoqi@0: 
aoqi@0:   if (TraceOopMapGeneration && Verbose) { tty->cr(); tty->print("Stack (%d): ", stack_top); }
aoqi@0:   for(int j = 0; j < stack_top; j++) {
aoqi@0:     bool v1 = is_oop(max_locals + j)  ? true : false;
aoqi@0:     bool v2 = stack[j].is_reference() ? true : false;
aoqi@0:     assert(v1 == v2, "stack oop mask generation error");
aoqi@0:     if (TraceOopMapGeneration && Verbose) tty->print("%d", v1 ? 1 : 0);
aoqi@0: #ifdef ENABLE_ZAP_DEAD_LOCALS
aoqi@0:     bool v3 = is_dead(max_locals + j) ? true : false;
aoqi@0:     bool v4 = !stack[j].is_live()     ? true : false;
aoqi@0:     assert(v3 == v4, "stack live mask generation error");
aoqi@0:     assert(!(v1 && v3), "dead value marked as oop");
aoqi@0: #endif
aoqi@0:   }
aoqi@0:   if (TraceOopMapGeneration && Verbose) tty->cr();
aoqi@0:   return true;
aoqi@0: }
aoqi@0: 
aoqi@0: void OopMapCacheEntry::allocate_bit_mask() {
aoqi@0:   if (mask_size() > small_mask_limit) {
aoqi@0:     assert(_bit_mask[0] == 0, "bit mask should be new or just flushed");
aoqi@0:     _bit_mask[0] = (intptr_t)
aoqi@0:       NEW_C_HEAP_ARRAY(uintptr_t, mask_word_size(), mtClass);
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: void OopMapCacheEntry::deallocate_bit_mask() {
aoqi@0:   if (mask_size() > small_mask_limit && _bit_mask[0] != 0) {
aoqi@0:     assert(!Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
aoqi@0:       "This bit mask should not be in the resource area");
aoqi@0:     FREE_C_HEAP_ARRAY(uintptr_t, _bit_mask[0], mtClass);
aoqi@0:     debug_only(_bit_mask[0] = 0;)
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void OopMapCacheEntry::fill_for_native(methodHandle mh) {
aoqi@0:   assert(mh->is_native(), "method must be native method");
aoqi@0:   set_mask_size(mh->size_of_parameters() * bits_per_entry);
aoqi@0:   allocate_bit_mask();
aoqi@0:   // fill mask for parameters
aoqi@0:   MaskFillerForNative mf(mh, bit_mask(), mask_size());
aoqi@0:   mf.generate();
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void OopMapCacheEntry::fill(methodHandle method, int bci) {
aoqi@0:   HandleMark hm;
aoqi@0:   // Flush entry to deallocate an existing entry
aoqi@0:   flush();
aoqi@0:   set_method(method());
aoqi@0:   set_bci(bci);
aoqi@0:   if (method->is_native()) {
aoqi@0:     // Native method activations have oops only among the parameters and one
aoqi@0:     // extra oop following the parameters (the mirror for static native methods).
aoqi@0:     fill_for_native(method);
aoqi@0:   } else {
aoqi@0:     EXCEPTION_MARK;
aoqi@0:     OopMapForCacheEntry gen(method, bci, this);
aoqi@0:     gen.compute_map(CATCH);
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: void OopMapCacheEntry::set_mask(CellTypeState *vars, CellTypeState *stack, int stack_top) {
aoqi@0:   // compute bit mask size
aoqi@0:   int max_locals = method()->max_locals();
aoqi@0:   int n_entries = max_locals + stack_top;
aoqi@0:   set_mask_size(n_entries * bits_per_entry);
aoqi@0:   allocate_bit_mask();
aoqi@0:   set_expression_stack_size(stack_top);
aoqi@0: 
aoqi@0:   // compute bits
aoqi@0:   int word_index = 0;
aoqi@0:   uintptr_t value = 0;
aoqi@0:   uintptr_t mask = 1;
aoqi@0: 
aoqi@0:   CellTypeState* cell = vars;
aoqi@0:   for (int entry_index = 0; entry_index < n_entries; entry_index++, mask <<= bits_per_entry, cell++) {
aoqi@0:     // store last word
aoqi@0:     if (mask == 0) {
aoqi@0:       bit_mask()[word_index++] = value;
aoqi@0:       value = 0;
aoqi@0:       mask = 1;
aoqi@0:     }
aoqi@0: 
aoqi@0:     // switch to stack when done with locals
aoqi@0:     if (entry_index == max_locals) {
aoqi@0:       cell = stack;
aoqi@0:     }
aoqi@0: 
aoqi@0:     // set oop bit
aoqi@0:     if ( cell->is_reference()) {
aoqi@0:       value |= (mask << oop_bit_number );
aoqi@0:     }
aoqi@0: 
aoqi@0:   #ifdef ENABLE_ZAP_DEAD_LOCALS
aoqi@0:     // set dead bit
aoqi@0:     if (!cell->is_live()) {
aoqi@0:       value |= (mask << dead_bit_number);
aoqi@0:       assert(!cell->is_reference(), "dead value marked as oop");
aoqi@0:     }
aoqi@0:   #endif
aoqi@0:   }
aoqi@0: 
aoqi@0:   // make sure last word is stored
aoqi@0:   bit_mask()[word_index] = value;
aoqi@0: 
aoqi@0:   // verify bit mask
aoqi@0:   assert(verify_mask(vars, stack, max_locals, stack_top), "mask could not be verified");
aoqi@0: 
aoqi@0: 
aoqi@0: }
aoqi@0: 
aoqi@0: void OopMapCacheEntry::flush() {
aoqi@0:   deallocate_bit_mask();
aoqi@0:   initialize();
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: // Implementation of OopMapCache
aoqi@0: 
aoqi@0: #ifndef PRODUCT
aoqi@0: 
aoqi@0: static long _total_memory_usage = 0;
aoqi@0: 
aoqi@0: long OopMapCache::memory_usage() {
aoqi@0:   return _total_memory_usage;
aoqi@0: }
aoqi@0: 
aoqi@0: #endif
aoqi@0: 
aoqi@0: void InterpreterOopMap::resource_copy(OopMapCacheEntry* from) {
aoqi@0:   assert(_resource_allocate_bit_mask,
aoqi@0:     "Should not resource allocate the _bit_mask");
aoqi@0: 
aoqi@0:   set_method(from->method());
aoqi@0:   set_bci(from->bci());
aoqi@0:   set_mask_size(from->mask_size());
aoqi@0:   set_expression_stack_size(from->expression_stack_size());
aoqi@0: 
aoqi@0:   // Is the bit mask contained in the entry?
aoqi@0:   if (from->mask_size() <= small_mask_limit) {
aoqi@0:     memcpy((void *)_bit_mask, (void *)from->_bit_mask,
aoqi@0:       mask_word_size() * BytesPerWord);
aoqi@0:   } else {
aoqi@0:     // The expectation is that this InterpreterOopMap is a recently created
aoqi@0:     // and empty. It is used to get a copy of a cached entry.
aoqi@0:     // If the bit mask has a value, it should be in the
aoqi@0:     // resource area.
aoqi@0:     assert(_bit_mask[0] == 0 ||
aoqi@0:       Thread::current()->resource_area()->contains((void*)_bit_mask[0]),
aoqi@0:       "The bit mask should have been allocated from a resource area");
aoqi@0:     // Allocate the bit_mask from a Resource area for performance.  Allocating
aoqi@0:     // from the C heap as is done for OopMapCache has a significant
aoqi@0:     // performance impact.
aoqi@0:     _bit_mask[0] = (uintptr_t) NEW_RESOURCE_ARRAY(uintptr_t, mask_word_size());
aoqi@0:     assert(_bit_mask[0] != 0, "bit mask was not allocated");
aoqi@0:     memcpy((void*) _bit_mask[0], (void*) from->_bit_mask[0],
aoqi@0:       mask_word_size() * BytesPerWord);
aoqi@0:   }
aoqi@0: }
aoqi@0: 
aoqi@0: inline unsigned int OopMapCache::hash_value_for(methodHandle method, int bci) {
aoqi@0:   // We use method->code_size() rather than method->identity_hash() below since
aoqi@0:   // the mark may not be present if a pointer to the method is already reversed.
aoqi@0:   return   ((unsigned int) bci)
aoqi@0:          ^ ((unsigned int) method->max_locals()         << 2)
aoqi@0:          ^ ((unsigned int) method->code_size()          << 4)
aoqi@0:          ^ ((unsigned int) method->size_of_parameters() << 6);
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: OopMapCache::OopMapCache() :
aoqi@0:   _mut(Mutex::leaf, "An OopMapCache lock", true)
aoqi@0: {
aoqi@0:   _array  = NEW_C_HEAP_ARRAY(OopMapCacheEntry, _size, mtClass);
aoqi@0:   // Cannot call flush for initialization, since flush
aoqi@0:   // will check if memory should be deallocated
aoqi@0:   for(int i = 0; i < _size; i++) _array[i].initialize();
aoqi@0:   NOT_PRODUCT(_total_memory_usage += sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
aoqi@0: }
aoqi@0: 
aoqi@0: 
aoqi@0: OopMapCache::~OopMapCache() {
aoqi@0:   assert(_array != NULL, "sanity check");
aoqi@0:   // Deallocate oop maps that are allocated out-of-line
aoqi@0:   flush();
aoqi@0:   // Deallocate array
aoqi@0:   NOT_PRODUCT(_total_memory_usage -= sizeof(OopMapCache) + (sizeof(OopMapCacheEntry) * _size);)
aoqi@0:   FREE_C_HEAP_ARRAY(OopMapCacheEntry, _array, mtClass);
aoqi@0: }
aoqi@0: 
aoqi@0: OopMapCacheEntry* OopMapCache::entry_at(int i) const {
aoqi@0:   return &_array[i % _size];
aoqi@0: }
aoqi@0: 
aoqi@0: void OopMapCache::flush() {
aoqi@0:   for (int i = 0; i < _size; i++) _array[i].flush();
aoqi@0: }
aoqi@0: 
aoqi@0: void OopMapCache::flush_obsolete_entries() {
aoqi@0:   for (int i = 0; i < _size; i++)
aoqi@0:     if (!_array[i].is_empty() && _array[i].method()->is_old()) {
aoqi@0:       // Cache entry is occupied by an old redefined method and we don't want
aoqi@0:       // to pin it down so flush the entry.
aoqi@0:       RC_TRACE(0x08000000, ("flush: %s(%s): cached entry @%d",
aoqi@0:         _array[i].method()->name()->as_C_string(),
aoqi@0:         _array[i].method()->signature()->as_C_string(), i));
aoqi@0: 
aoqi@0:       _array[i].flush();
aoqi@0:     }
aoqi@0: }
aoqi@0: 
aoqi@0: void OopMapCache::lookup(methodHandle method,
aoqi@0:                          int bci,
aoqi@0:                          InterpreterOopMap* entry_for) {
aoqi@0:   MutexLocker x(&_mut);
aoqi@0: 
aoqi@0:   OopMapCacheEntry* entry = NULL;
aoqi@0:   int probe = hash_value_for(method, bci);
aoqi@0: 
aoqi@0:   // Search hashtable for match
aoqi@0:   int i;
aoqi@0:   for(i = 0; i < _probe_depth; i++) {
aoqi@0:     entry = entry_at(probe + i);
aoqi@0:     if (entry->match(method, bci)) {
aoqi@0:       entry_for->resource_copy(entry);
aoqi@0:       assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
aoqi@0:       return;
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
aoqi@0:   if (TraceOopMapGeneration) {
aoqi@0:     static int count = 0;
aoqi@0:     ResourceMark rm;
aoqi@0:     tty->print("%d - Computing oopmap at bci %d for ", ++count, bci);
aoqi@0:     method->print_value(); tty->cr();
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Entry is not in hashtable.
aoqi@0:   // Compute entry and return it
aoqi@0: 
aoqi@0:   if (method->should_not_be_cached()) {
aoqi@0:     // It is either not safe or not a good idea to cache this Method*
aoqi@0:     // at this time. We give the caller of lookup() a copy of the
aoqi@0:     // interesting info via parameter entry_for, but we don't add it to
aoqi@0:     // the cache. See the gory details in Method*.cpp.
aoqi@0:     compute_one_oop_map(method, bci, entry_for);
aoqi@0:     return;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // First search for an empty slot
aoqi@0:   for(i = 0; i < _probe_depth; i++) {
aoqi@0:     entry  = entry_at(probe + i);
aoqi@0:     if (entry->is_empty()) {
aoqi@0:       entry->fill(method, bci);
aoqi@0:       entry_for->resource_copy(entry);
aoqi@0:       assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
aoqi@0:       return;
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
aoqi@0:   if (TraceOopMapGeneration) {
aoqi@0:     ResourceMark rm;
aoqi@0:     tty->print_cr("*** collision in oopmap cache - flushing item ***");
aoqi@0:   }
aoqi@0: 
aoqi@0:   // No empty slot (uncommon case). Use (some approximation of a) LRU algorithm
aoqi@0:   //entry_at(probe + _probe_depth - 1)->flush();
aoqi@0:   //for(i = _probe_depth - 1; i > 0; i--) {
aoqi@0:   //  // Coping entry[i] = entry[i-1];
aoqi@0:   //  OopMapCacheEntry *to   = entry_at(probe + i);
aoqi@0:   //  OopMapCacheEntry *from = entry_at(probe + i - 1);
aoqi@0:   //  to->copy(from);
aoqi@0:   // }
aoqi@0: 
aoqi@0:   assert(method->is_method(), "gaga");
aoqi@0: 
aoqi@0:   entry = entry_at(probe + 0);
aoqi@0:   entry->fill(method, bci);
aoqi@0: 
aoqi@0:   // Copy the  newly cached entry to input parameter
aoqi@0:   entry_for->resource_copy(entry);
aoqi@0: 
aoqi@0:   if (TraceOopMapGeneration) {
aoqi@0:     ResourceMark rm;
aoqi@0:     tty->print("Done with ");
aoqi@0:     method->print_value(); tty->cr();
aoqi@0:   }
aoqi@0:   assert(!entry_for->is_empty(), "A non-empty oop map should be returned");
aoqi@0: 
aoqi@0:   return;
aoqi@0: }
aoqi@0: 
aoqi@0: void OopMapCache::compute_one_oop_map(methodHandle method, int bci, InterpreterOopMap* entry) {
aoqi@0:   // Due to the invariants above it's tricky to allocate a temporary OopMapCacheEntry on the stack
aoqi@0:   OopMapCacheEntry* tmp = NEW_C_HEAP_ARRAY(OopMapCacheEntry, 1, mtClass);
aoqi@0:   tmp->initialize();
aoqi@0:   tmp->fill(method, bci);
aoqi@0:   entry->resource_copy(tmp);
aoqi@0:   FREE_C_HEAP_ARRAY(OopMapCacheEntry, tmp, mtInternal);
aoqi@0: }