Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2000, 2013, 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

  * questions.

  *

  */

 #ifndef SHARE_VM_OOPS_METHODDATAOOP_HPP

 #define SHARE_VM_OOPS_METHODDATAOOP_HPP

 #include "interpreter/bytecodes.hpp"

 #include "memory/universe.hpp"

 #include "oops/method.hpp"

 #include "oops/oop.hpp"

 #include "runtime/orderAccess.hpp"

 class BytecodeStream;

 class KlassSizeStats;

 // The MethodData object collects counts and other profile information

 // during zeroth-tier (interpretive) and first-tier execution.

 // The profile is used later by compilation heuristics.  Some heuristics

 // enable use of aggressive (or "heroic") optimizations.  An aggressive

 // optimization often has a down-side, a corner case that it handles

 // poorly, but which is thought to be rare.  The profile provides

 // evidence of this rarity for a given method or even BCI.  It allows

 // the compiler to back out of the optimization at places where it

 // has historically been a poor choice.  Other heuristics try to use

 // specific information gathered about types observed at a given site.

 //

 // All data in the profile is approximate.  It is expected to be accurate

 // on the whole, but the system expects occasional inaccuraces, due to

 // counter overflow, multiprocessor races during data collection, space

 // limitations, missing MDO blocks, etc.  Bad or missing data will degrade

 // optimization quality but will not affect correctness.  Also, each MDO

 // is marked with its birth-date ("creation_mileage") which can be used

 // to assess the quality ("maturity") of its data.

 //

 // Short (<32-bit) counters are designed to overflow to a known "saturated"

 // state.  Also, certain recorded per-BCI events are given one-bit counters

 // which overflow to a saturated state which applied to all counters at

 // that BCI.  In other words, there is a small lattice which approximates

 // the ideal of an infinite-precision counter for each event at each BCI,

 // and the lattice quickly "bottoms out" in a state where all counters

 // are taken to be indefinitely large.

 //

 // The reader will find many data races in profile gathering code, starting

 // with invocation counter incrementation.  None of these races harm correct

 // execution of the compiled code.

 // forward decl

 class ProfileData;

 // DataLayout

 //

 // Overlay for generic profiling data.

 class DataLayout VALUE_OBJ_CLASS_SPEC {

   friend class VMStructs;

 private:

   // Every data layout begins with a header.  This header

   // contains a tag, which is used to indicate the size/layout

   // of the data, 4 bits of flags, which can be used in any way,

   // 4 bits of trap history (none/one reason/many reasons),

   // and a bci, which is used to tie this piece of data to a

   // specific bci in the bytecodes.

   union {

     intptr_t _bits;

     struct {

       u1 _tag;

       u1 _flags;

       u2 _bci;

     } _struct;

   } _header;

   // The data layout has an arbitrary number of cells, each sized

   // to accomodate a pointer or an integer.

   intptr_t _cells[1];

   // Some types of data layouts need a length field.

   static bool needs_array_len(u1 tag);

 public:

   enum {

     counter_increment = 1

   };

   enum {

     cell_size = sizeof(intptr_t)

   };

   // Tag values

   enum {

     no_tag,

     bit_data_tag,

     counter_data_tag,

     jump_data_tag,

     receiver_type_data_tag,

     virtual_call_data_tag,

     ret_data_tag,

     branch_data_tag,

     multi_branch_data_tag,

     arg_info_data_tag,

     call_type_data_tag,

     virtual_call_type_data_tag,

     parameters_type_data_tag

   };

   enum {

     // The _struct._flags word is formatted as [trap_state:4 | flags:4].

     // The trap state breaks down further as [recompile:1 | reason:3].

     // This further breakdown is defined in deoptimization.cpp.

     // See Deoptimization::trap_state_reason for an assert that

     // trap_bits is big enough to hold reasons < Reason_RECORDED_LIMIT.

     //

     // The trap_state is collected only if ProfileTraps is true.

     trap_bits = 1+3,  // 3: enough to distinguish [0..Reason_RECORDED_LIMIT].

     trap_shift = BitsPerByte - trap_bits,

     trap_mask = right_n_bits(trap_bits),

     trap_mask_in_place = (trap_mask << trap_shift),

     flag_limit = trap_shift,

     flag_mask = right_n_bits(flag_limit),

     first_flag = 0

   };

   // Size computation

   static int header_size_in_bytes() {

     return cell_size;

   }

   static int header_size_in_cells() {

     return 1;

   }

   static int compute_size_in_bytes(int cell_count) {

     return header_size_in_bytes() + cell_count * cell_size;

   }

   // Initialization

   void initialize(u1 tag, u2 bci, int cell_count);

   // Accessors

   u1 tag() {

     return _header._struct._tag;

   }

   // Return a few bits of trap state.  Range is [0..trap_mask].

   // The state tells if traps with zero, one, or many reasons have occurred.

   // It also tells whether zero or many recompilations have occurred.

   // The associated trap histogram in the MDO itself tells whether

   // traps are common or not.  If a BCI shows that a trap X has

   // occurred, and the MDO shows N occurrences of X, we make the

   // simplifying assumption that all N occurrences can be blamed

   // on that BCI.

   int trap_state() const {

     return ((_header._struct._flags >> trap_shift) & trap_mask);

   }

   void set_trap_state(int new_state) {

     assert(ProfileTraps, "used only under +ProfileTraps");

     uint old_flags = (_header._struct._flags & flag_mask);

     _header._struct._flags = (new_state << trap_shift) | old_flags;

   }

   u1 flags() const {

     return _header._struct._flags;

   }

   u2 bci() const {

     return _header._struct._bci;

   }

   void set_header(intptr_t value) {

     _header._bits = value;

   }

   void release_set_header(intptr_t value) {

     OrderAccess::release_store_ptr(&_header._bits, value);

   }

   intptr_t header() {

     return _header._bits;

   }

   void set_cell_at(int index, intptr_t value) {

     _cells[index] = value;

   }

   void release_set_cell_at(int index, intptr_t value) {

     OrderAccess::release_store_ptr(&_cells[index], value);

   }

   intptr_t cell_at(int index) const {

     return _cells[index];

   }

   void set_flag_at(int flag_number) {

     assert(flag_number < flag_limit, "oob");

     _header._struct._flags |= (0x1 << flag_number);

   }

   bool flag_at(int flag_number) const {

     assert(flag_number < flag_limit, "oob");

     return (_header._struct._flags & (0x1 << flag_number)) != 0;

   }

   // Low-level support for code generation.

   static ByteSize header_offset() {

     return byte_offset_of(DataLayout, _header);

   }

   static ByteSize tag_offset() {

     return byte_offset_of(DataLayout, _header._struct._tag);

   }

   static ByteSize flags_offset() {

     return byte_offset_of(DataLayout, _header._struct._flags);

   }

   static ByteSize bci_offset() {

     return byte_offset_of(DataLayout, _header._struct._bci);

   }

   static ByteSize cell_offset(int index) {

     return byte_offset_of(DataLayout, _cells) + in_ByteSize(index * cell_size);

   }

   // Return a value which, when or-ed as a byte into _flags, sets the flag.

   static int flag_number_to_byte_constant(int flag_number) {

     assert(0 <= flag_number && flag_number < flag_limit, "oob");

     DataLayout temp; temp.set_header(0);

     temp.set_flag_at(flag_number);

     return temp._header._struct._flags;

   }

   // Return a value which, when or-ed as a word into _header, sets the flag.

   static intptr_t flag_mask_to_header_mask(int byte_constant) {

     DataLayout temp; temp.set_header(0);

     temp._header._struct._flags = byte_constant;

     return temp._header._bits;

   }

   ProfileData* data_in();

   // GC support

   void clean_weak_klass_links(BoolObjectClosure* cl);

 };

 // ProfileData class hierarchy

 class ProfileData;

 class   BitData;

 class     CounterData;

 class       ReceiverTypeData;

 class         VirtualCallData;

 class           VirtualCallTypeData;

 class       RetData;

 class       CallTypeData;

 class   JumpData;

 class     BranchData;

 class   ArrayData;

 class     MultiBranchData;

 class     ArgInfoData;

 class     ParametersTypeData;

 // ProfileData

 //

 // A ProfileData object is created to refer to a section of profiling

 // data in a structured way.

 class ProfileData : public ResourceObj {

   friend class TypeEntries;

   friend class ReturnTypeEntry;

   friend class TypeStackSlotEntries;

 private:

 #ifndef PRODUCT

   enum {

     tab_width_one = 16,

     tab_width_two = 36

   };

 #endif // !PRODUCT

   // This is a pointer to a section of profiling data.

   DataLayout* _data;

 protected:

   DataLayout* data() { return _data; }

   const DataLayout* data() const { return _data; }

   enum {

     cell_size = DataLayout::cell_size

   };

 public:

   // How many cells are in this?

   virtual int cell_count() const {

     ShouldNotReachHere();

     return -1;

   }

   // Return the size of this data.

   int size_in_bytes() {

     return DataLayout::compute_size_in_bytes(cell_count());

   }

 protected:

   // Low-level accessors for underlying data

   void set_intptr_at(int index, intptr_t value) {

     assert(0 <= index && index < cell_count(), "oob");

     data()->set_cell_at(index, value);

   }

   void release_set_intptr_at(int index, intptr_t value) {

     assert(0 <= index && index < cell_count(), "oob");

     data()->release_set_cell_at(index, value);

   }

   intptr_t intptr_at(int index) const {

     assert(0 <= index && index < cell_count(), "oob");

     return data()->cell_at(index);

   }

   void set_uint_at(int index, uint value) {

     set_intptr_at(index, (intptr_t) value);

   }

   void release_set_uint_at(int index, uint value) {

     release_set_intptr_at(index, (intptr_t) value);

   }

   uint uint_at(int index) const {

     return (uint)intptr_at(index);

   }

   void set_int_at(int index, int value) {

     set_intptr_at(index, (intptr_t) value);

   }

   void release_set_int_at(int index, int value) {

     release_set_intptr_at(index, (intptr_t) value);

   }

   int int_at(int index) const {

     return (int)intptr_at(index);

   }

   int int_at_unchecked(int index) const {

     return (int)data()->cell_at(index);

   }

   void set_oop_at(int index, oop value) {

     set_intptr_at(index, cast_from_oop<intptr_t>(value));

   }

   oop oop_at(int index) const {

     return cast_to_oop(intptr_at(index));

   }

   void set_flag_at(int flag_number) {

     data()->set_flag_at(flag_number);

   }

   bool flag_at(int flag_number) const {

     return data()->flag_at(flag_number);

   }

   // two convenient imports for use by subclasses:

   static ByteSize cell_offset(int index) {

     return DataLayout::cell_offset(index);

   }

   static int flag_number_to_byte_constant(int flag_number) {

     return DataLayout::flag_number_to_byte_constant(flag_number);

   }

   ProfileData(DataLayout* data) {

     _data = data;

   }

 public:

   // Constructor for invalid ProfileData.

   ProfileData();

   u2 bci() const {

     return data()->bci();

   }

   address dp() {

     return (address)_data;

   }

   int trap_state() const {

     return data()->trap_state();

   }

   void set_trap_state(int new_state) {

     data()->set_trap_state(new_state);

   }

   // Type checking

   virtual bool is_BitData()         const { return false; }

   virtual bool is_CounterData()     const { return false; }

   virtual bool is_JumpData()        const { return false; }

   virtual bool is_ReceiverTypeData()const { return false; }

   virtual bool is_VirtualCallData() const { return false; }

   virtual bool is_RetData()         const { return false; }

   virtual bool is_BranchData()      const { return false; }

   virtual bool is_ArrayData()       const { return false; }

   virtual bool is_MultiBranchData() const { return false; }

   virtual bool is_ArgInfoData()     const { return false; }

   virtual bool is_CallTypeData()    const { return false; }

   virtual bool is_VirtualCallTypeData()const { return false; }

   virtual bool is_ParametersTypeData() const { return false; }

   BitData* as_BitData() const {

     assert(is_BitData(), "wrong type");

     return is_BitData()         ? (BitData*)        this : NULL;

   }

   CounterData* as_CounterData() const {

     assert(is_CounterData(), "wrong type");

     return is_CounterData()     ? (CounterData*)    this : NULL;

   }

   JumpData* as_JumpData() const {

     assert(is_JumpData(), "wrong type");

     return is_JumpData()        ? (JumpData*)       this : NULL;

   }

   ReceiverTypeData* as_ReceiverTypeData() const {

     assert(is_ReceiverTypeData(), "wrong type");

     return is_ReceiverTypeData() ? (ReceiverTypeData*)this : NULL;

   }

   VirtualCallData* as_VirtualCallData() const {

     assert(is_VirtualCallData(), "wrong type");

     return is_VirtualCallData() ? (VirtualCallData*)this : NULL;

   }

   RetData* as_RetData() const {

     assert(is_RetData(), "wrong type");

     return is_RetData()         ? (RetData*)        this : NULL;

   }

   BranchData* as_BranchData() const {

     assert(is_BranchData(), "wrong type");

     return is_BranchData()      ? (BranchData*)     this : NULL;

   }

   ArrayData* as_ArrayData() const {

     assert(is_ArrayData(), "wrong type");

     return is_ArrayData()       ? (ArrayData*)      this : NULL;

   }

   MultiBranchData* as_MultiBranchData() const {

     assert(is_MultiBranchData(), "wrong type");

     return is_MultiBranchData() ? (MultiBranchData*)this : NULL;

   }

   ArgInfoData* as_ArgInfoData() const {

     assert(is_ArgInfoData(), "wrong type");

     return is_ArgInfoData() ? (ArgInfoData*)this : NULL;

   }

   CallTypeData* as_CallTypeData() const {

     assert(is_CallTypeData(), "wrong type");

     return is_CallTypeData() ? (CallTypeData*)this : NULL;

   }

   VirtualCallTypeData* as_VirtualCallTypeData() const {

     assert(is_VirtualCallTypeData(), "wrong type");

     return is_VirtualCallTypeData() ? (VirtualCallTypeData*)this : NULL;

   }

   ParametersTypeData* as_ParametersTypeData() const {

     assert(is_ParametersTypeData(), "wrong type");

     return is_ParametersTypeData() ? (ParametersTypeData*)this : NULL;

   }

   // Subclass specific initialization

   virtual void post_initialize(BytecodeStream* stream, MethodData* mdo) {}

   // GC support

   virtual void clean_weak_klass_links(BoolObjectClosure* is_alive_closure) {}

   // CI translation: ProfileData can represent both MethodDataOop data

   // as well as CIMethodData data. This function is provided for translating

   // an oop in a ProfileData to the ci equivalent. Generally speaking,

   // most ProfileData don't require any translation, so we provide the null

   // translation here, and the required translators are in the ci subclasses.

   virtual void translate_from(const ProfileData* data) {}

   virtual void print_data_on(outputStream* st) const {

     ShouldNotReachHere();

   }

 #ifndef PRODUCT

   void print_shared(outputStream* st, const char* name) const;

   void tab(outputStream* st, bool first = false) const;

 #endif

 };

 // BitData

 //

 // A BitData holds a flag or two in its header.

 class BitData : public ProfileData {

 protected:

   enum {

     // null_seen:

     //  saw a null operand (cast/aastore/instanceof)

     null_seen_flag              = DataLayout::first_flag + 0

   };

   enum { bit_cell_count = 0 };  // no additional data fields needed.

 public:

   BitData(DataLayout* layout) : ProfileData(layout) {

   }

   virtual bool is_BitData() const { return true; }

   static int static_cell_count() {

     return bit_cell_count;

   }

   virtual int cell_count() const {

     return static_cell_count();

   }

   // Accessor

   // The null_seen flag bit is specially known to the interpreter.

   // Consulting it allows the compiler to avoid setting up null_check traps.

   bool null_seen()     { return flag_at(null_seen_flag); }

   void set_null_seen()    { set_flag_at(null_seen_flag); }

   // Code generation support

   static int null_seen_byte_constant() {

     return flag_number_to_byte_constant(null_seen_flag);

   }

   static ByteSize bit_data_size() {

     return cell_offset(bit_cell_count);

   }

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 // CounterData

 //

 // A CounterData corresponds to a simple counter.

 class CounterData : public BitData {

 protected:

   enum {

     count_off,

     counter_cell_count

   };

 public:

   CounterData(DataLayout* layout) : BitData(layout) {}

   virtual bool is_CounterData() const { return true; }

   static int static_cell_count() {

     return counter_cell_count;

   }

   virtual int cell_count() const {

     return static_cell_count();

   }

   // Direct accessor

   uint count() const {

     return uint_at(count_off);

   }

   // Code generation support

   static ByteSize count_offset() {

     return cell_offset(count_off);

   }

   static ByteSize counter_data_size() {

     return cell_offset(counter_cell_count);

   }

   void set_count(uint count) {

     set_uint_at(count_off, count);

   }

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 // JumpData

 //

 // A JumpData is used to access profiling information for a direct

 // branch.  It is a counter, used for counting the number of branches,

 // plus a data displacement, used for realigning the data pointer to

 // the corresponding target bci.

 class JumpData : public ProfileData {

 protected:

   enum {

     taken_off_set,

     displacement_off_set,

     jump_cell_count

   };

   void set_displacement(int displacement) {

     set_int_at(displacement_off_set, displacement);

   }

 public:

   JumpData(DataLayout* layout) : ProfileData(layout) {

     assert(layout->tag() == DataLayout::jump_data_tag ||

       layout->tag() == DataLayout::branch_data_tag, "wrong type");

   }

   virtual bool is_JumpData() const { return true; }

   static int static_cell_count() {

     return jump_cell_count;

   }

   virtual int cell_count() const {

     return static_cell_count();

   }

   // Direct accessor

   uint taken() const {

     return uint_at(taken_off_set);

   }

   void set_taken(uint cnt) {

     set_uint_at(taken_off_set, cnt);

   }

   // Saturating counter

   uint inc_taken() {

     uint cnt = taken() + 1;

     // Did we wrap? Will compiler screw us??

     if (cnt == 0) cnt--;

     set_uint_at(taken_off_set, cnt);

     return cnt;

   }

   int displacement() const {

     return int_at(displacement_off_set);

   }

   // Code generation support

   static ByteSize taken_offset() {

     return cell_offset(taken_off_set);

   }

   static ByteSize displacement_offset() {

     return cell_offset(displacement_off_set);

   }

   // Specific initialization.

   void post_initialize(BytecodeStream* stream, MethodData* mdo);

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 // Entries in a ProfileData object to record types: it can either be

 // none (no profile), unknown (conflicting profile data) or a klass if

 // a single one is seen. Whether a null reference was seen is also

 // recorded. No counter is associated with the type and a single type

 // is tracked (unlike VirtualCallData).

 class TypeEntries {

 public:

   // A single cell is used to record information for a type:

   // - the cell is initialized to 0

   // - when a type is discovered it is stored in the cell

   // - bit zero of the cell is used to record whether a null reference

   // was encountered or not

   // - bit 1 is set to record a conflict in the type information

   enum {

     null_seen = 1,

     type_mask = ~null_seen,

     type_unknown = 2,

     status_bits = null_seen | type_unknown,

     type_klass_mask = ~status_bits

   };

   // what to initialize a cell to

   static intptr_t type_none() {

     return 0;

   }

   // null seen = bit 0 set?

   static bool was_null_seen(intptr_t v) {

     return (v & null_seen) != 0;

   }

   // conflicting type information = bit 1 set?

   static bool is_type_unknown(intptr_t v) {

     return (v & type_unknown) != 0;

   }

   // not type information yet = all bits cleared, ignoring bit 0?

   static bool is_type_none(intptr_t v) {

     return (v & type_mask) == 0;

   }

   // recorded type: cell without bit 0 and 1

   static intptr_t klass_part(intptr_t v) {

     intptr_t r = v & type_klass_mask;

     assert (r != 0, "invalid");

     return r;

   }

   // type recorded

   static Klass* valid_klass(intptr_t k) {

     if (!is_type_none(k) &&

         !is_type_unknown(k)) {

       return (Klass*)klass_part(k);

     } else {

       return NULL;

     }

   }

   static intptr_t with_status(intptr_t k, intptr_t in) {

     return k | (in & status_bits);

   }

   static intptr_t with_status(Klass* k, intptr_t in) {

     return with_status((intptr_t)k, in);

   }

 #ifndef PRODUCT

   static void print_klass(outputStream* st, intptr_t k);

 #endif

   // GC support

   static bool is_loader_alive(BoolObjectClosure* is_alive_cl, intptr_t p);

 protected:

   // ProfileData object these entries are part of

   ProfileData* _pd;

   // offset within the ProfileData object where the entries start

   const int _base_off;

   TypeEntries(int base_off)

     : _base_off(base_off), _pd(NULL) {}

   void set_intptr_at(int index, intptr_t value) {

     _pd->set_intptr_at(index, value);

   }

   intptr_t intptr_at(int index) const {

     return _pd->intptr_at(index);

   }

 public:

   void set_profile_data(ProfileData* pd) {

     _pd = pd;

   }

 };

 // Type entries used for arguments passed at a call and parameters on

 // method entry. 2 cells per entry: one for the type encoded as in

 // TypeEntries and one initialized with the stack slot where the

 // profiled object is to be found so that the interpreter can locate

 // it quickly.

 class TypeStackSlotEntries : public TypeEntries {

 private:

   enum {

     stack_slot_entry,

     type_entry,

     per_arg_cell_count

   };

   // offset of cell for stack slot for entry i within ProfileData object

   int stack_slot_offset(int i) const {

     return _base_off + stack_slot_local_offset(i);

   }

 protected:

   const int _number_of_entries;

   // offset of cell for type for entry i within ProfileData object

   int type_offset(int i) const {

     return _base_off + type_local_offset(i);

   }

 public:

   TypeStackSlotEntries(int base_off, int nb_entries)

     : TypeEntries(base_off), _number_of_entries(nb_entries) {}

   static int compute_cell_count(Symbol* signature, bool include_receiver, int max);

   void post_initialize(Symbol* signature, bool has_receiver, bool include_receiver);

   // offset of cell for stack slot for entry i within this block of cells for a TypeStackSlotEntries

   static int stack_slot_local_offset(int i) {

     return i * per_arg_cell_count + stack_slot_entry;

   }

   // offset of cell for type for entry i within this block of cells for a TypeStackSlotEntries

   static int type_local_offset(int i) {

     return i * per_arg_cell_count + type_entry;

   }

   // stack slot for entry i

   uint stack_slot(int i) const {

     assert(i >= 0 && i < _number_of_entries, "oob");

     return _pd->uint_at(stack_slot_offset(i));

   }

   // set stack slot for entry i

   void set_stack_slot(int i, uint num) {

     assert(i >= 0 && i < _number_of_entries, "oob");

     _pd->set_uint_at(stack_slot_offset(i), num);

   }

   // type for entry i

   intptr_t type(int i) const {

     assert(i >= 0 && i < _number_of_entries, "oob");

     return _pd->intptr_at(type_offset(i));

   }

   // set type for entry i

   void set_type(int i, intptr_t k) {

     assert(i >= 0 && i < _number_of_entries, "oob");

     _pd->set_intptr_at(type_offset(i), k);

   }

   static ByteSize per_arg_size() {

     return in_ByteSize(per_arg_cell_count * DataLayout::cell_size);

   }

   static int per_arg_count() {

     return per_arg_cell_count ;

   }

   // GC support

   void clean_weak_klass_links(BoolObjectClosure* is_alive_closure);

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 // Type entry used for return from a call. A single cell to record the

 // type.

 class ReturnTypeEntry : public TypeEntries {

 private:

   enum {

     cell_count = 1

   };

 public:

   ReturnTypeEntry(int base_off)

     : TypeEntries(base_off) {}

   void post_initialize() {

     set_type(type_none());

   }

   intptr_t type() const {

     return _pd->intptr_at(_base_off);

   }

   void set_type(intptr_t k) {

     _pd->set_intptr_at(_base_off, k);

   }

   static int static_cell_count() {

     return cell_count;

   }

   static ByteSize size() {

     return in_ByteSize(cell_count * DataLayout::cell_size);

   }

   ByteSize type_offset() {

     return DataLayout::cell_offset(_base_off);

   }

   // GC support

   void clean_weak_klass_links(BoolObjectClosure* is_alive_closure);

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 // Entries to collect type information at a call: contains arguments

 // (TypeStackSlotEntries), a return type (ReturnTypeEntry) and a

 // number of cells. Because the number of cells for the return type is

 // smaller than the number of cells for the type of an arguments, the

 // number of cells is used to tell how many arguments are profiled and

 // whether a return value is profiled. See has_arguments() and

 // has_return().

 class TypeEntriesAtCall {

 private:

   static int stack_slot_local_offset(int i) {

     return header_cell_count() + TypeStackSlotEntries::stack_slot_local_offset(i);

   }

   static int argument_type_local_offset(int i) {

     return header_cell_count() + TypeStackSlotEntries::type_local_offset(i);;

   }

 public:

   static int header_cell_count() {

     return 1;

   }

   static int cell_count_local_offset() {

     return 0;

   }

   static int compute_cell_count(BytecodeStream* stream);

   static void initialize(DataLayout* dl, int base, int cell_count) {

     int off = base + cell_count_local_offset();

     dl->set_cell_at(off, cell_count - base - header_cell_count());

   }

   static bool arguments_profiling_enabled();

   static bool return_profiling_enabled();

   // Code generation support

   static ByteSize cell_count_offset() {

     return in_ByteSize(cell_count_local_offset() * DataLayout::cell_size);

   }

   static ByteSize args_data_offset() {

     return in_ByteSize(header_cell_count() * DataLayout::cell_size);

   }

   static ByteSize stack_slot_offset(int i) {

     return in_ByteSize(stack_slot_local_offset(i) * DataLayout::cell_size);

   }

   static ByteSize argument_type_offset(int i) {

     return in_ByteSize(argument_type_local_offset(i) * DataLayout::cell_size);

   }

 };

 // CallTypeData

 //

 // A CallTypeData is used to access profiling information about a non

 // virtual call for which we collect type information about arguments

 // and return value.

 class CallTypeData : public CounterData {

 private:

   // entries for arguments if any

   TypeStackSlotEntries _args;

   // entry for return type if any

   ReturnTypeEntry _ret;

   int cell_count_global_offset() const {

     return CounterData::static_cell_count() + TypeEntriesAtCall::cell_count_local_offset();

   }

   // number of cells not counting the header

   int cell_count_no_header() const {

     return uint_at(cell_count_global_offset());

   }

   void check_number_of_arguments(int total) {

     assert(number_of_arguments() == total, "should be set in DataLayout::initialize");

   }

 public:

   CallTypeData(DataLayout* layout) :

     CounterData(layout),

     _args(CounterData::static_cell_count()+TypeEntriesAtCall::header_cell_count(), number_of_arguments()),

     _ret(cell_count() - ReturnTypeEntry::static_cell_count())

   {

     assert(layout->tag() == DataLayout::call_type_data_tag, "wrong type");

     // Some compilers (VC++) don't want this passed in member initialization list

     _args.set_profile_data(this);

     _ret.set_profile_data(this);

   }

   const TypeStackSlotEntries* args() const {

     assert(has_arguments(), "no profiling of arguments");

     return &_args;

   }

   const ReturnTypeEntry* ret() const {

     assert(has_return(), "no profiling of return value");

     return &_ret;

   }

   virtual bool is_CallTypeData() const { return true; }

   static int static_cell_count() {

     return -1;

   }

   static int compute_cell_count(BytecodeStream* stream) {

     return CounterData::static_cell_count() + TypeEntriesAtCall::compute_cell_count(stream);

   }

   static void initialize(DataLayout* dl, int cell_count) {

     TypeEntriesAtCall::initialize(dl, CounterData::static_cell_count(), cell_count);

   }

   virtual void post_initialize(BytecodeStream* stream, MethodData* mdo);

   virtual int cell_count() const {

     return CounterData::static_cell_count() +

       TypeEntriesAtCall::header_cell_count() +

       int_at_unchecked(cell_count_global_offset());

   }

   int number_of_arguments() const {

     return cell_count_no_header() / TypeStackSlotEntries::per_arg_count();

   }

   void set_argument_type(int i, Klass* k) {

     assert(has_arguments(), "no arguments!");

     intptr_t current = _args.type(i);

     _args.set_type(i, TypeEntries::with_status(k, current));

   }

   void set_return_type(Klass* k) {

     assert(has_return(), "no return!");

     intptr_t current = _ret.type();

     _ret.set_type(TypeEntries::with_status(k, current));

   }

   // An entry for a return value takes less space than an entry for an

   // argument so if the number of cells exceeds the number of cells

   // needed for an argument, this object contains type information for

   // at least one argument.

   bool has_arguments() const {

     bool res = cell_count_no_header() >= TypeStackSlotEntries::per_arg_count();

     assert (!res || TypeEntriesAtCall::arguments_profiling_enabled(), "no profiling of arguments");

     return res;

   }

   // An entry for a return value takes less space than an entry for an

   // argument, so if the remainder of the number of cells divided by

   // the number of cells for an argument is not null, a return value

   // is profiled in this object.

   bool has_return() const {

     bool res = (cell_count_no_header() % TypeStackSlotEntries::per_arg_count()) != 0;

     assert (!res || TypeEntriesAtCall::return_profiling_enabled(), "no profiling of return values");

     return res;

   }

   // Code generation support

   static ByteSize args_data_offset() {

     return cell_offset(CounterData::static_cell_count()) + TypeEntriesAtCall::args_data_offset();

   }

   // GC support

   virtual void clean_weak_klass_links(BoolObjectClosure* is_alive_closure) {

     if (has_arguments()) {

       _args.clean_weak_klass_links(is_alive_closure);

     }

     if (has_return()) {

       _ret.clean_weak_klass_links(is_alive_closure);

     }

   }

 #ifndef PRODUCT

   virtual void print_data_on(outputStream* st) const;

 #endif

 };

 // ReceiverTypeData

 //

 // A ReceiverTypeData is used to access profiling information about a

 // dynamic type check.  It consists of a counter which counts the total times

 // that the check is reached, and a series of (Klass*, count) pairs

 // which are used to store a type profile for the receiver of the check.

 class ReceiverTypeData : public CounterData {

 protected:

   enum {

     receiver0_offset = counter_cell_count,

     count0_offset,

     receiver_type_row_cell_count = (count0_offset + 1) - receiver0_offset

   };

 public:

   ReceiverTypeData(DataLayout* layout) : CounterData(layout) {

     assert(layout->tag() == DataLayout::receiver_type_data_tag ||

            layout->tag() == DataLayout::virtual_call_data_tag ||

            layout->tag() == DataLayout::virtual_call_type_data_tag, "wrong type");

   }

   virtual bool is_ReceiverTypeData() const { return true; }

   static int static_cell_count() {

     return counter_cell_count + (uint) TypeProfileWidth * receiver_type_row_cell_count;

   }

   virtual int cell_count() const {

     return static_cell_count();

   }

   // Direct accessors

   static uint row_limit() {

     return TypeProfileWidth;

   }

   static int receiver_cell_index(uint row) {

     return receiver0_offset + row * receiver_type_row_cell_count;

   }

   static int receiver_count_cell_index(uint row) {

     return count0_offset + row * receiver_type_row_cell_count;

   }

   Klass* receiver(uint row) const {

     assert(row < row_limit(), "oob");

     Klass* recv = (Klass*)intptr_at(receiver_cell_index(row));

     assert(recv == NULL || recv->is_klass(), "wrong type");

     return recv;

   }

   void set_receiver(uint row, Klass* k) {

     assert((uint)row < row_limit(), "oob");

     set_intptr_at(receiver_cell_index(row), (uintptr_t)k);

   }

   uint receiver_count(uint row) const {

     assert(row < row_limit(), "oob");

     return uint_at(receiver_count_cell_index(row));

   }

   void set_receiver_count(uint row, uint count) {

     assert(row < row_limit(), "oob");

     set_uint_at(receiver_count_cell_index(row), count);

   }

   void clear_row(uint row) {

     assert(row < row_limit(), "oob");

     // Clear total count - indicator of polymorphic call site.

     // The site may look like as monomorphic after that but

     // it allow to have more accurate profiling information because

     // there was execution phase change since klasses were unloaded.

     // If the site is still polymorphic then MDO will be updated

     // to reflect it. But it could be the case that the site becomes

     // only bimorphic. Then keeping total count not 0 will be wrong.

     // Even if we use monomorphic (when it is not) for compilation

     // we will only have trap, deoptimization and recompile again

     // with updated MDO after executing method in Interpreter.

     // An additional receiver will be recorded in the cleaned row

     // during next call execution.

     //

     // Note: our profiling logic works with empty rows in any slot.

     // We do sorting a profiling info (ciCallProfile) for compilation.

     //

     set_count(0);

     set_receiver(row, NULL);

     set_receiver_count(row, 0);

   }

   // Code generation support

   static ByteSize receiver_offset(uint row) {

     return cell_offset(receiver_cell_index(row));

   }

   static ByteSize receiver_count_offset(uint row) {

     return cell_offset(receiver_count_cell_index(row));

   }

   static ByteSize receiver_type_data_size() {

     return cell_offset(static_cell_count());

   }

   // GC support

   virtual void clean_weak_klass_links(BoolObjectClosure* is_alive_closure);

 #ifndef PRODUCT

   void print_receiver_data_on(outputStream* st) const;

   void print_data_on(outputStream* st) const;

 #endif

 };

 // VirtualCallData

 //

 // A VirtualCallData is used to access profiling information about a

 // virtual call.  For now, it has nothing more than a ReceiverTypeData.

 class VirtualCallData : public ReceiverTypeData {

 public:

   VirtualCallData(DataLayout* layout) : ReceiverTypeData(layout) {

     assert(layout->tag() == DataLayout::virtual_call_data_tag ||

            layout->tag() == DataLayout::virtual_call_type_data_tag, "wrong type");

   }

   virtual bool is_VirtualCallData() const { return true; }

   static int static_cell_count() {

     // At this point we could add more profile state, e.g., for arguments.

     // But for now it's the same size as the base record type.

     return ReceiverTypeData::static_cell_count();

   }

   virtual int cell_count() const {

     return static_cell_count();

   }

   // Direct accessors

   static ByteSize virtual_call_data_size() {

     return cell_offset(static_cell_count());

   }

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 // VirtualCallTypeData

 //

 // A VirtualCallTypeData is used to access profiling information about

 // a virtual call for which we collect type information about

 // arguments and return value.

 class VirtualCallTypeData : public VirtualCallData {

 private:

   // entries for arguments if any

   TypeStackSlotEntries _args;

   // entry for return type if any

   ReturnTypeEntry _ret;

   int cell_count_global_offset() const {

     return VirtualCallData::static_cell_count() + TypeEntriesAtCall::cell_count_local_offset();

   }

   // number of cells not counting the header

   int cell_count_no_header() const {

     return uint_at(cell_count_global_offset());

   }

   void check_number_of_arguments(int total) {

     assert(number_of_arguments() == total, "should be set in DataLayout::initialize");

   }

 public:

   VirtualCallTypeData(DataLayout* layout) :

     VirtualCallData(layout),

     _args(VirtualCallData::static_cell_count()+TypeEntriesAtCall::header_cell_count(), number_of_arguments()),

     _ret(cell_count() - ReturnTypeEntry::static_cell_count())

   {

     assert(layout->tag() == DataLayout::virtual_call_type_data_tag, "wrong type");

     // Some compilers (VC++) don't want this passed in member initialization list

     _args.set_profile_data(this);

     _ret.set_profile_data(this);

   }

   const TypeStackSlotEntries* args() const {

     assert(has_arguments(), "no profiling of arguments");

     return &_args;

   }

   const ReturnTypeEntry* ret() const {

     assert(has_return(), "no profiling of return value");

     return &_ret;

   }

   virtual bool is_VirtualCallTypeData() const { return true; }

   static int static_cell_count() {

     return -1;

   }

   static int compute_cell_count(BytecodeStream* stream) {

     return VirtualCallData::static_cell_count() + TypeEntriesAtCall::compute_cell_count(stream);

   }

   static void initialize(DataLayout* dl, int cell_count) {

     TypeEntriesAtCall::initialize(dl, VirtualCallData::static_cell_count(), cell_count);

   }

   virtual void post_initialize(BytecodeStream* stream, MethodData* mdo);

   virtual int cell_count() const {

     return VirtualCallData::static_cell_count() +

       TypeEntriesAtCall::header_cell_count() +

       int_at_unchecked(cell_count_global_offset());

   }

   int number_of_arguments() const {

     return cell_count_no_header() / TypeStackSlotEntries::per_arg_count();

   }

   void set_argument_type(int i, Klass* k) {

     assert(has_arguments(), "no arguments!");

     intptr_t current = _args.type(i);

     _args.set_type(i, TypeEntries::with_status(k, current));

   }

   void set_return_type(Klass* k) {

     assert(has_return(), "no return!");

     intptr_t current = _ret.type();

     _ret.set_type(TypeEntries::with_status(k, current));

   }

   // An entry for a return value takes less space than an entry for an

   // argument, so if the remainder of the number of cells divided by

   // the number of cells for an argument is not null, a return value

   // is profiled in this object.

   bool has_return() const {

     bool res = (cell_count_no_header() % TypeStackSlotEntries::per_arg_count()) != 0;

     assert (!res || TypeEntriesAtCall::return_profiling_enabled(), "no profiling of return values");

     return res;

   }

   // An entry for a return value takes less space than an entry for an

   // argument so if the number of cells exceeds the number of cells

   // needed for an argument, this object contains type information for

   // at least one argument.

   bool has_arguments() const {

     bool res = cell_count_no_header() >= TypeStackSlotEntries::per_arg_count();

     assert (!res || TypeEntriesAtCall::arguments_profiling_enabled(), "no profiling of arguments");

     return res;

   }

   // Code generation support

   static ByteSize args_data_offset() {

     return cell_offset(VirtualCallData::static_cell_count()) + TypeEntriesAtCall::args_data_offset();

   }

   // GC support

   virtual void clean_weak_klass_links(BoolObjectClosure* is_alive_closure) {

     ReceiverTypeData::clean_weak_klass_links(is_alive_closure);

     if (has_arguments()) {

       _args.clean_weak_klass_links(is_alive_closure);

     }

     if (has_return()) {

       _ret.clean_weak_klass_links(is_alive_closure);

     }

   }

 #ifndef PRODUCT

   virtual void print_data_on(outputStream* st) const;

 #endif

 };

 // RetData

 //

 // A RetData is used to access profiling information for a ret bytecode.

 // It is composed of a count of the number of times that the ret has

 // been executed, followed by a series of triples of the form

 // (bci, count, di) which count the number of times that some bci was the

 // target of the ret and cache a corresponding data displacement.

 class RetData : public CounterData {

 protected:

   enum {

     bci0_offset = counter_cell_count,

     count0_offset,

     displacement0_offset,

     ret_row_cell_count = (displacement0_offset + 1) - bci0_offset

   };

   void set_bci(uint row, int bci) {

     assert((uint)row < row_limit(), "oob");

     set_int_at(bci0_offset + row * ret_row_cell_count, bci);

   }

   void release_set_bci(uint row, int bci) {

     assert((uint)row < row_limit(), "oob");

     // 'release' when setting the bci acts as a valid flag for other

     // threads wrt bci_count and bci_displacement.

     release_set_int_at(bci0_offset + row * ret_row_cell_count, bci);

   }

   void set_bci_count(uint row, uint count) {

     assert((uint)row < row_limit(), "oob");

     set_uint_at(count0_offset + row * ret_row_cell_count, count);

   }

   void set_bci_displacement(uint row, int disp) {

     set_int_at(displacement0_offset + row * ret_row_cell_count, disp);

   }

 public:

   RetData(DataLayout* layout) : CounterData(layout) {

     assert(layout->tag() == DataLayout::ret_data_tag, "wrong type");

   }

   virtual bool is_RetData() const { return true; }

   enum {

     no_bci = -1 // value of bci when bci1/2 are not in use.

   };

   static int static_cell_count() {

     return counter_cell_count + (uint) BciProfileWidth * ret_row_cell_count;

   }

   virtual int cell_count() const {

     return static_cell_count();

   }

   static uint row_limit() {

     return BciProfileWidth;

   }

   static int bci_cell_index(uint row) {

     return bci0_offset + row * ret_row_cell_count;

   }

   static int bci_count_cell_index(uint row) {

     return count0_offset + row * ret_row_cell_count;

   }

   static int bci_displacement_cell_index(uint row) {

     return displacement0_offset + row * ret_row_cell_count;

   }

   // Direct accessors

   int bci(uint row) const {

     return int_at(bci_cell_index(row));

   }

   uint bci_count(uint row) const {

     return uint_at(bci_count_cell_index(row));

   }

   int bci_displacement(uint row) const {

     return int_at(bci_displacement_cell_index(row));

   }

   // Interpreter Runtime support

   address fixup_ret(int return_bci, MethodData* mdo);

   // Code generation support

   static ByteSize bci_offset(uint row) {

     return cell_offset(bci_cell_index(row));

   }

   static ByteSize bci_count_offset(uint row) {

     return cell_offset(bci_count_cell_index(row));

   }

   static ByteSize bci_displacement_offset(uint row) {

     return cell_offset(bci_displacement_cell_index(row));

   }

   // Specific initialization.

   void post_initialize(BytecodeStream* stream, MethodData* mdo);

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 // BranchData

 //

 // A BranchData is used to access profiling data for a two-way branch.

 // It consists of taken and not_taken counts as well as a data displacement

 // for the taken case.

 class BranchData : public JumpData {

 protected:

   enum {

     not_taken_off_set = jump_cell_count,

     branch_cell_count

   };

   void set_displacement(int displacement) {

     set_int_at(displacement_off_set, displacement);

   }

 public:

   BranchData(DataLayout* layout) : JumpData(layout) {

     assert(layout->tag() == DataLayout::branch_data_tag, "wrong type");

   }

   virtual bool is_BranchData() const { return true; }

   static int static_cell_count() {

     return branch_cell_count;

   }

   virtual int cell_count() const {

     return static_cell_count();

   }

   // Direct accessor

   uint not_taken() const {

     return uint_at(not_taken_off_set);

   }

   void set_not_taken(uint cnt) {

     set_uint_at(not_taken_off_set, cnt);

   }

   uint inc_not_taken() {

     uint cnt = not_taken() + 1;

     // Did we wrap? Will compiler screw us??

     if (cnt == 0) cnt--;

     set_uint_at(not_taken_off_set, cnt);

     return cnt;

   }

   // Code generation support

   static ByteSize not_taken_offset() {

     return cell_offset(not_taken_off_set);

   }

   static ByteSize branch_data_size() {

     return cell_offset(branch_cell_count);

   }

   // Specific initialization.

   void post_initialize(BytecodeStream* stream, MethodData* mdo);

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 // ArrayData

 //

 // A ArrayData is a base class for accessing profiling data which does

 // not have a statically known size.  It consists of an array length

 // and an array start.

 class ArrayData : public ProfileData {

 protected:

   friend class DataLayout;

   enum {

     array_len_off_set,

     array_start_off_set

   };

   uint array_uint_at(int index) const {

     int aindex = index + array_start_off_set;

     return uint_at(aindex);

   }

   int array_int_at(int index) const {

     int aindex = index + array_start_off_set;

     return int_at(aindex);

   }

   oop array_oop_at(int index) const {

     int aindex = index + array_start_off_set;

     return oop_at(aindex);

   }

   void array_set_int_at(int index, int value) {

     int aindex = index + array_start_off_set;

     set_int_at(aindex, value);

   }

   // Code generation support for subclasses.

   static ByteSize array_element_offset(int index) {

     return cell_offset(array_start_off_set + index);

   }

 public:

   ArrayData(DataLayout* layout) : ProfileData(layout) {}

   virtual bool is_ArrayData() const { return true; }

   static int static_cell_count() {

     return -1;

   }

   int array_len() const {

     return int_at_unchecked(array_len_off_set);

   }

   virtual int cell_count() const {

     return array_len() + 1;

   }

   // Code generation support

   static ByteSize array_len_offset() {

     return cell_offset(array_len_off_set);

   }

   static ByteSize array_start_offset() {

     return cell_offset(array_start_off_set);

   }

 };

 // MultiBranchData

 //

 // A MultiBranchData is used to access profiling information for

 // a multi-way branch (*switch bytecodes).  It consists of a series

 // of (count, displacement) pairs, which count the number of times each

 // case was taken and specify the data displacment for each branch target.

 class MultiBranchData : public ArrayData {

 protected:

   enum {

     default_count_off_set,

     default_disaplacement_off_set,

     case_array_start

   };

   enum {

     relative_count_off_set,

     relative_displacement_off_set,

     per_case_cell_count

   };

   void set_default_displacement(int displacement) {

     array_set_int_at(default_disaplacement_off_set, displacement);

   }

   void set_displacement_at(int index, int displacement) {

     array_set_int_at(case_array_start +

                      index * per_case_cell_count +

                      relative_displacement_off_set,

                      displacement);

   }

 public:

   MultiBranchData(DataLayout* layout) : ArrayData(layout) {

     assert(layout->tag() == DataLayout::multi_branch_data_tag, "wrong type");

   }

   virtual bool is_MultiBranchData() const { return true; }

   static int compute_cell_count(BytecodeStream* stream);

   int number_of_cases() const {

     int alen = array_len() - 2; // get rid of default case here.

     assert(alen % per_case_cell_count == 0, "must be even");

     return (alen / per_case_cell_count);

   }

   uint default_count() const {

     return array_uint_at(default_count_off_set);

   }

   int default_displacement() const {

     return array_int_at(default_disaplacement_off_set);

   }

   uint count_at(int index) const {

     return array_uint_at(case_array_start +

                          index * per_case_cell_count +

                          relative_count_off_set);

   }

   int displacement_at(int index) const {

     return array_int_at(case_array_start +

                         index * per_case_cell_count +

                         relative_displacement_off_set);

   }

   // Code generation support

   static ByteSize default_count_offset() {

     return array_element_offset(default_count_off_set);

   }

   static ByteSize default_displacement_offset() {

     return array_element_offset(default_disaplacement_off_set);

   }

   static ByteSize case_count_offset(int index) {

     return case_array_offset() +

            (per_case_size() * index) +

            relative_count_offset();

   }

   static ByteSize case_array_offset() {

     return array_element_offset(case_array_start);

   }

   static ByteSize per_case_size() {

     return in_ByteSize(per_case_cell_count) * cell_size;

   }

   static ByteSize relative_count_offset() {

     return in_ByteSize(relative_count_off_set) * cell_size;

   }

   static ByteSize relative_displacement_offset() {

     return in_ByteSize(relative_displacement_off_set) * cell_size;

   }

   // Specific initialization.

   void post_initialize(BytecodeStream* stream, MethodData* mdo);

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 class ArgInfoData : public ArrayData {

 public:

   ArgInfoData(DataLayout* layout) : ArrayData(layout) {

     assert(layout->tag() == DataLayout::arg_info_data_tag, "wrong type");

   }

   virtual bool is_ArgInfoData() const { return true; }

   int number_of_args() const {

     return array_len();

   }

   uint arg_modified(int arg) const {

     return array_uint_at(arg);

   }

   void set_arg_modified(int arg, uint val) {

     array_set_int_at(arg, val);

   }

 #ifndef PRODUCT

   void print_data_on(outputStream* st) const;

 #endif

 };

 // ParametersTypeData

 //

 // A ParametersTypeData is used to access profiling information about

 // types of parameters to a method

 class ParametersTypeData : public ArrayData {

 private:

   TypeStackSlotEntries _parameters;

   static int stack_slot_local_offset(int i) {

     assert_profiling_enabled();

     return array_start_off_set + TypeStackSlotEntries::stack_slot_local_offset(i);

   }

   static int type_local_offset(int i) {

     assert_profiling_enabled();

     return array_start_off_set + TypeStackSlotEntries::type_local_offset(i);

   }

   static bool profiling_enabled();

   static void assert_profiling_enabled() {

     assert(profiling_enabled(), "method parameters profiling should be on");

   }

 public:

   ParametersTypeData(DataLayout* layout) : ArrayData(layout), _parameters(1, number_of_parameters()) {

     assert(layout->tag() == DataLayout::parameters_type_data_tag, "wrong type");

     // Some compilers (VC++) don't want this passed in member initialization list

     _parameters.set_profile_data(this);

   }

   static int compute_cell_count(Method* m);

   virtual bool is_ParametersTypeData() const { return true; }

   virtual void post_initialize(BytecodeStream* stream, MethodData* mdo);

   int number_of_parameters() const {

     return array_len() / TypeStackSlotEntries::per_arg_count();

   }

   const TypeStackSlotEntries* parameters() const { return &_parameters; }

   uint stack_slot(int i) const {

     return _parameters.stack_slot(i);

   }

   void set_type(int i, Klass* k) {

     intptr_t current = _parameters.type(i);

     _parameters.set_type(i, TypeEntries::with_status((intptr_t)k, current));

   }

   virtual void clean_weak_klass_links(BoolObjectClosure* is_alive_closure) {

     _parameters.clean_weak_klass_links(is_alive_closure);

   }

 #ifndef PRODUCT

   virtual void print_data_on(outputStream* st) const;

 #endif

   static ByteSize stack_slot_offset(int i) {

     return cell_offset(stack_slot_local_offset(i));

   }

   static ByteSize type_offset(int i) {

     return cell_offset(type_local_offset(i));

   }

 };

 // MethodData*

 //

 // A MethodData* holds information which has been collected about

 // a method.  Its layout looks like this:

 //

 // -----------------------------

 // | header                    |

 // | klass                     |

 // -----------------------------

 // | method                    |

 // | size of the MethodData* |

 // -----------------------------

 // | Data entries...           |

 // |   (variable size)         |

 // |                           |

 // .                           .

 // .                           .

 // .                           .

 // |                           |

 // -----------------------------

 //

 // The data entry area is a heterogeneous array of DataLayouts. Each

 // DataLayout in the array corresponds to a specific bytecode in the

 // method.  The entries in the array are sorted by the corresponding

 // bytecode.  Access to the data is via resource-allocated ProfileData,

 // which point to the underlying blocks of DataLayout structures.

 //

 // During interpretation, if profiling in enabled, the interpreter

 // maintains a method data pointer (mdp), which points at the entry

 // in the array corresponding to the current bci.  In the course of

 // intepretation, when a bytecode is encountered that has profile data

 // associated with it, the entry pointed to by mdp is updated, then the

 // mdp is adjusted to point to the next appropriate DataLayout.  If mdp

 // is NULL to begin with, the interpreter assumes that the current method

 // is not (yet) being profiled.

 //

 // In MethodData* parlance, "dp" is a "data pointer", the actual address

 // of a DataLayout element.  A "di" is a "data index", the offset in bytes

 // from the base of the data entry array.  A "displacement" is the byte offset

 // in certain ProfileData objects that indicate the amount the mdp must be

 // adjusted in the event of a change in control flow.

 //

 class MethodData : public Metadata {

   friend class VMStructs;

 private:

   friend class ProfileData;

   // Back pointer to the Method*

   Method* _method;

   // Size of this oop in bytes

   int _size;

   // Cached hint for bci_to_dp and bci_to_data

   int _hint_di;

   MethodData(methodHandle method, int size, TRAPS);

 public:

   static MethodData* allocate(ClassLoaderData* loader_data, methodHandle method, TRAPS);

   MethodData() {}; // For ciMethodData

   bool is_methodData() const volatile { return true; }

   // Whole-method sticky bits and flags

   enum {

     _trap_hist_limit    = 17,   // decoupled from Deoptimization::Reason_LIMIT

     _trap_hist_mask     = max_jubyte,

     _extra_data_count   = 4     // extra DataLayout headers, for trap history

   }; // Public flag values

 private:

   uint _nof_decompiles;             // count of all nmethod removals

   uint _nof_overflow_recompiles;    // recompile count, excluding recomp. bits

   uint _nof_overflow_traps;         // trap count, excluding _trap_hist

   union {

     intptr_t _align;

     u1 _array[_trap_hist_limit];

   } _trap_hist;

   // Support for interprocedural escape analysis, from Thomas Kotzmann.

   intx              _eflags;          // flags on escape information

   intx              _arg_local;       // bit set of non-escaping arguments

   intx              _arg_stack;       // bit set of stack-allocatable arguments

   intx              _arg_returned;    // bit set of returned arguments

   int _creation_mileage;              // method mileage at MDO creation

   // How many invocations has this MDO seen?

   // These counters are used to determine the exact age of MDO.

   // We need those because in tiered a method can be concurrently

   // executed at different levels.

   InvocationCounter _invocation_counter;

   // Same for backedges.

   InvocationCounter _backedge_counter;

   // Counter values at the time profiling started.

   int               _invocation_counter_start;

   int               _backedge_counter_start;

   // Number of loops and blocks is computed when compiling the first

   // time with C1. It is used to determine if method is trivial.

   short             _num_loops;

   short             _num_blocks;

   // Highest compile level this method has ever seen.

   u1                _highest_comp_level;

   // Same for OSR level

   u1                _highest_osr_comp_level;

   // Does this method contain anything worth profiling?

   bool              _would_profile;

   // Size of _data array in bytes.  (Excludes header and extra_data fields.)

   int _data_size;

   // data index for the area dedicated to parameters. -1 if no

   // parameter profiling.

   int _parameters_type_data_di;

   // Beginning of the data entries

   intptr_t _data[1];

   // Helper for size computation

   static int compute_data_size(BytecodeStream* stream);

   static int bytecode_cell_count(Bytecodes::Code code);

   enum { no_profile_data = -1, variable_cell_count = -2 };

   // Helper for initialization

   DataLayout* data_layout_at(int data_index) const {

     assert(data_index % sizeof(intptr_t) == 0, "unaligned");

     return (DataLayout*) (((address)_data) + data_index);

   }

   // Initialize an individual data segment.  Returns the size of

   // the segment in bytes.

   int initialize_data(BytecodeStream* stream, int data_index);

   // Helper for data_at

   DataLayout* limit_data_position() const {

     return (DataLayout*)((address)data_base() + _data_size);

   }

   bool out_of_bounds(int data_index) const {

     return data_index >= data_size();

   }

   // Give each of the data entries a chance to perform specific

   // data initialization.

   void post_initialize(BytecodeStream* stream);

   // hint accessors

   int      hint_di() const  { return _hint_di; }

   void set_hint_di(int di)  {

     assert(!out_of_bounds(di), "hint_di out of bounds");

     _hint_di = di;

   }

   ProfileData* data_before(int bci) {

     // avoid SEGV on this edge case

     if (data_size() == 0)

       return NULL;

     int hint = hint_di();

     if (data_layout_at(hint)->bci() <= bci)

       return data_at(hint);

     return first_data();

   }

   // What is the index of the first data entry?

   int first_di() const { return 0; }

   // Find or create an extra ProfileData:

   ProfileData* bci_to_extra_data(int bci, bool create_if_missing);

   // return the argument info cell

   ArgInfoData *arg_info();

   enum {

     no_type_profile = 0,

     type_profile_jsr292 = 1,

     type_profile_all = 2

   };

   static bool profile_jsr292(methodHandle m, int bci);

   static int profile_arguments_flag();

   static bool profile_arguments_jsr292_only();

   static bool profile_all_arguments();

   static bool profile_arguments_for_invoke(methodHandle m, int bci);

   static int profile_return_flag();

   static bool profile_all_return();

   static bool profile_return_for_invoke(methodHandle m, int bci);

   static int profile_parameters_flag();

   static bool profile_parameters_jsr292_only();

   static bool profile_all_parameters();

 public:

   static int header_size() {

     return sizeof(MethodData)/wordSize;

   }

   // Compute the size of a MethodData* before it is created.

   static int compute_allocation_size_in_bytes(methodHandle method);

   static int compute_allocation_size_in_words(methodHandle method);

   static int compute_extra_data_count(int data_size, int empty_bc_count);

   // Determine if a given bytecode can have profile information.

   static bool bytecode_has_profile(Bytecodes::Code code) {

     return bytecode_cell_count(code) != no_profile_data;

   }

   // reset into original state

   void init();

   // My size

   int size_in_bytes() const { return _size; }

   int size() const    { return align_object_size(align_size_up(_size, BytesPerWord)/BytesPerWord); }

 #if INCLUDE_SERVICES

   void collect_statistics(KlassSizeStats *sz) const;

 #endif

   int      creation_mileage() const  { return _creation_mileage; }

   void set_creation_mileage(int x)   { _creation_mileage = x; }

   int invocation_count() {

     if (invocation_counter()->carry()) {

       return InvocationCounter::count_limit;

     }

     return invocation_counter()->count();

   }

   int backedge_count() {

     if (backedge_counter()->carry()) {

       return InvocationCounter::count_limit;

     }

     return backedge_counter()->count();

   }

   int invocation_count_start() {

     if (invocation_counter()->carry()) {

       return 0;

     }

     return _invocation_counter_start;

   }

   int backedge_count_start() {

     if (backedge_counter()->carry()) {

       return 0;

     }

     return _backedge_counter_start;

   }

   int invocation_count_delta() { return invocation_count() - invocation_count_start(); }

   int backedge_count_delta()   { return backedge_count()   - backedge_count_start();   }

   void reset_start_counters() {

     _invocation_counter_start = invocation_count();

     _backedge_counter_start = backedge_count();

   }

   InvocationCounter* invocation_counter()     { return &_invocation_counter; }

   InvocationCounter* backedge_counter()       { return &_backedge_counter;   }

   void set_would_profile(bool p)              { _would_profile = p;    }

   bool would_profile() const                  { return _would_profile; }

   int highest_comp_level() const              { return _highest_comp_level;      }

   void set_highest_comp_level(int level)      { _highest_comp_level = level;     }

   int highest_osr_comp_level() const          { return _highest_osr_comp_level;  }

   void set_highest_osr_comp_level(int level)  { _highest_osr_comp_level = level; }

   int num_loops() const                       { return _num_loops;  }

   void set_num_loops(int n)                   { _num_loops = n;     }

   int num_blocks() const                      { return _num_blocks; }

   void set_num_blocks(int n)                  { _num_blocks = n;    }

   bool is_mature() const;  // consult mileage and ProfileMaturityPercentage

   static int mileage_of(Method* m);

   // Support for interprocedural escape analysis, from Thomas Kotzmann.

   enum EscapeFlag {

     estimated    = 1 << 0,

     return_local = 1 << 1,

     return_allocated = 1 << 2,

     allocated_escapes = 1 << 3,

     unknown_modified = 1 << 4

   };

   intx eflags()                                  { return _eflags; }

   intx arg_local()                               { return _arg_local; }

   intx arg_stack()                               { return _arg_stack; }

   intx arg_returned()                            { return _arg_returned; }

   uint arg_modified(int a)                       { ArgInfoData *aid = arg_info();

                                                    assert(aid != NULL, "arg_info must be not null");

                                                    assert(a >= 0 && a < aid->number_of_args(), "valid argument number");

                                                    return aid->arg_modified(a); }

   void set_eflags(intx v)                        { _eflags = v; }

   void set_arg_local(intx v)                     { _arg_local = v; }

   void set_arg_stack(intx v)                     { _arg_stack = v; }

   void set_arg_returned(intx v)                  { _arg_returned = v; }

   void set_arg_modified(int a, uint v)           { ArgInfoData *aid = arg_info();

                                                    assert(aid != NULL, "arg_info must be not null");

                                                    assert(a >= 0 && a < aid->number_of_args(), "valid argument number");

                                                    aid->set_arg_modified(a, v); }

   void clear_escape_info()                       { _eflags = _arg_local = _arg_stack = _arg_returned = 0; }

   // Location and size of data area

   address data_base() const {

     return (address) _data;

   }

   int data_size() const {

     return _data_size;

   }

   // Accessors

   Method* method() const { return _method; }

   // Get the data at an arbitrary (sort of) data index.

   ProfileData* data_at(int data_index) const;

   // Walk through the data in order.

   ProfileData* first_data() const { return data_at(first_di()); }

   ProfileData* next_data(ProfileData* current) const;

   bool is_valid(ProfileData* current) const { return current != NULL; }

   // Convert a dp (data pointer) to a di (data index).

   int dp_to_di(address dp) const {

     return dp - ((address)_data);

   }

   address di_to_dp(int di) {

     return (address)data_layout_at(di);

   }

   // bci to di/dp conversion.

   address bci_to_dp(int bci);

   int bci_to_di(int bci) {

     return dp_to_di(bci_to_dp(bci));

   }

   // Get the data at an arbitrary bci, or NULL if there is none.

   ProfileData* bci_to_data(int bci);

   // Same, but try to create an extra_data record if one is needed:

   ProfileData* allocate_bci_to_data(int bci) {

     ProfileData* data = bci_to_data(bci);

     return (data != NULL) ? data : bci_to_extra_data(bci, true);

   }

   // Add a handful of extra data records, for trap tracking.

   DataLayout* extra_data_base() const { return limit_data_position(); }

   DataLayout* extra_data_limit() const { return (DataLayout*)((address)this + size_in_bytes()); }

   int extra_data_size() const { return (address)extra_data_limit()

                                - (address)extra_data_base(); }

   static DataLayout* next_extra(DataLayout* dp) { return (DataLayout*)((address)dp + in_bytes(DataLayout::cell_offset(0))); }

   // Return (uint)-1 for overflow.

   uint trap_count(int reason) const {

     assert((uint)reason < _trap_hist_limit, "oob");

     return (int)((_trap_hist._array[reason]+1) & _trap_hist_mask) - 1;

   }

   // For loops:

   static uint trap_reason_limit() { return _trap_hist_limit; }

   static uint trap_count_limit()  { return _trap_hist_mask; }

   uint inc_trap_count(int reason) {

     // Count another trap, anywhere in this method.

     assert(reason >= 0, "must be single trap");

     if ((uint)reason < _trap_hist_limit) {

       uint cnt1 = 1 + _trap_hist._array[reason];

       if ((cnt1 & _trap_hist_mask) != 0) {  // if no counter overflow...

         _trap_hist._array[reason] = cnt1;

         return cnt1;

       } else {

         return _trap_hist_mask + (++_nof_overflow_traps);

       }

     } else {

       // Could not represent the count in the histogram.

       return (++_nof_overflow_traps);

     }

   }

   uint overflow_trap_count() const {

     return _nof_overflow_traps;

   }

   uint overflow_recompile_count() const {

     return _nof_overflow_recompiles;

   }

   void inc_overflow_recompile_count() {

     _nof_overflow_recompiles += 1;

   }

   uint decompile_count() const {

     return _nof_decompiles;

   }

   void inc_decompile_count() {

     _nof_decompiles += 1;

     if (decompile_count() > (uint)PerMethodRecompilationCutoff) {

       method()->set_not_compilable(CompLevel_full_optimization, true, "decompile_count > PerMethodRecompilationCutoff");

     }

   }

   // Return pointer to area dedicated to parameters in MDO

   ParametersTypeData* parameters_type_data() const {

     return _parameters_type_data_di != -1 ? data_layout_at(_parameters_type_data_di)->data_in()->as_ParametersTypeData() : NULL;

   }

   int parameters_type_data_di() const {

     assert(_parameters_type_data_di != -1, "no args type data");

     return _parameters_type_data_di;

   }

   // Support for code generation

   static ByteSize data_offset() {

     return byte_offset_of(MethodData, _data[0]);

   }

   static ByteSize invocation_counter_offset() {

     return byte_offset_of(MethodData, _invocation_counter);

   }

   static ByteSize backedge_counter_offset() {

     return byte_offset_of(MethodData, _backedge_counter);

   }

   static ByteSize parameters_type_data_di_offset() {

     return byte_offset_of(MethodData, _parameters_type_data_di);

   }

   // Deallocation support - no pointer fields to deallocate

   void deallocate_contents(ClassLoaderData* loader_data) {}

   // GC support

   void set_size(int object_size_in_bytes) { _size = object_size_in_bytes; }

   // Printing

 #ifndef PRODUCT

   void print_on      (outputStream* st) const;

 #endif

   void print_value_on(outputStream* st) const;

 #ifndef PRODUCT

   // printing support for method data

   void print_data_on(outputStream* st) const;

 #endif

   const char* internal_name() const { return "{method data}"; }

   // verification

   void verify_on(outputStream* st);

   void verify_data_on(outputStream* st);

   static bool profile_parameters_for_method(methodHandle m);

   static bool profile_arguments();

   static bool profile_return();

   static bool profile_parameters();

   static bool profile_return_jsr292_only();

 };

 #endif // SHARE_VM_OOPS_METHODDATAOOP_HPP