--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/oops/methodData.hpp	Mon Nov 12 23:14:12 2012 +0100
@@ -0,0 +1,1508 @@
+/*
+ * Copyright (c) 2000, 2012, 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;
+
+// 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 {
+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
+  };
+
+  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() {
+    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() {
+    return _header._struct._flags;
+  }
+
+  u2 bci() {
+    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) {
+    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) {
+    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       RetData;
+class   JumpData;
+class     BranchData;
+class   ArrayData;
+class     MultiBranchData;
+class     ArgInfoData;
+
+
+// ProfileData
+//
+// A ProfileData object is created to refer to a section of profiling
+// data in a structured way.
+class ProfileData : public ResourceObj {
+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; }
+
+  enum {
+    cell_size = DataLayout::cell_size
+  };
+
+public:
+  // How many cells are in this?
+  virtual int cell_count() {
+    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) {
+    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) {
+    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) {
+    return (int)intptr_at(index);
+  }
+  int int_at_unchecked(int index) {
+    return (int)data()->cell_at(index);
+  }
+  void set_oop_at(int index, oop value) {
+    set_intptr_at(index, (intptr_t) value);
+  }
+  oop oop_at(int index) {
+    return (oop)intptr_at(index);
+  }
+
+  void set_flag_at(int flag_number) {
+    data()->set_flag_at(flag_number);
+  }
+  bool flag_at(int flag_number) {
+    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() {
+    return data()->bci();
+  }
+
+  address dp() {
+    return (address)_data;
+  }
+
+  int trap_state() {
+    return data()->trap_state();
+  }
+  void set_trap_state(int new_state) {
+    data()->set_trap_state(new_state);
+  }
+
+  // Type checking
+  virtual bool is_BitData()         { return false; }
+  virtual bool is_CounterData()     { return false; }
+  virtual bool is_JumpData()        { return false; }
+  virtual bool is_ReceiverTypeData(){ return false; }
+  virtual bool is_VirtualCallData() { return false; }
+  virtual bool is_RetData()         { return false; }
+  virtual bool is_BranchData()      { return false; }
+  virtual bool is_ArrayData()       { return false; }
+  virtual bool is_MultiBranchData() { return false; }
+  virtual bool is_ArgInfoData()     { return false; }
+
+
+  BitData* as_BitData() {
+    assert(is_BitData(), "wrong type");
+    return is_BitData()         ? (BitData*)        this : NULL;
+  }
+  CounterData* as_CounterData() {
+    assert(is_CounterData(), "wrong type");
+    return is_CounterData()     ? (CounterData*)    this : NULL;
+  }
+  JumpData* as_JumpData() {
+    assert(is_JumpData(), "wrong type");
+    return is_JumpData()        ? (JumpData*)       this : NULL;
+  }
+  ReceiverTypeData* as_ReceiverTypeData() {
+    assert(is_ReceiverTypeData(), "wrong type");
+    return is_ReceiverTypeData() ? (ReceiverTypeData*)this : NULL;
+  }
+  VirtualCallData* as_VirtualCallData() {
+    assert(is_VirtualCallData(), "wrong type");
+    return is_VirtualCallData() ? (VirtualCallData*)this : NULL;
+  }
+  RetData* as_RetData() {
+    assert(is_RetData(), "wrong type");
+    return is_RetData()         ? (RetData*)        this : NULL;
+  }
+  BranchData* as_BranchData() {
+    assert(is_BranchData(), "wrong type");
+    return is_BranchData()      ? (BranchData*)     this : NULL;
+  }
+  ArrayData* as_ArrayData() {
+    assert(is_ArrayData(), "wrong type");
+    return is_ArrayData()       ? (ArrayData*)      this : NULL;
+  }
+  MultiBranchData* as_MultiBranchData() {
+    assert(is_MultiBranchData(), "wrong type");
+    return is_MultiBranchData() ? (MultiBranchData*)this : NULL;
+  }
+  ArgInfoData* as_ArgInfoData() {
+    assert(is_ArgInfoData(), "wrong type");
+    return is_ArgInfoData() ? (ArgInfoData*)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(ProfileData* data) {}
+
+  virtual void print_data_on(outputStream* st) {
+    ShouldNotReachHere();
+  }
+
+#ifndef PRODUCT
+  void print_shared(outputStream* st, const char* name);
+  void tab(outputStream* st);
+#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() { return true; }
+
+  static int static_cell_count() {
+    return bit_cell_count;
+  }
+
+  virtual int cell_count() {
+    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);
+#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() { return true; }
+
+  static int static_cell_count() {
+    return counter_cell_count;
+  }
+
+  virtual int cell_count() {
+    return static_cell_count();
+  }
+
+  // Direct accessor
+  uint count() {
+    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);
+#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() { return true; }
+
+  static int static_cell_count() {
+    return jump_cell_count;
+  }
+
+  virtual int cell_count() {
+    return static_cell_count();
+  }
+
+  // Direct accessor
+  uint taken() {
+    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() {
+    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);
+#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, "wrong type");
+  }
+
+  virtual bool is_ReceiverTypeData() { return true; }
+
+  static int static_cell_count() {
+    return counter_cell_count + (uint) TypeProfileWidth * receiver_type_row_cell_count;
+  }
+
+  virtual int cell_count() {
+    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) {
+    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) {
+    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);
+  void print_data_on(outputStream* st);
+#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, "wrong type");
+  }
+
+  virtual bool is_VirtualCallData() { 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() {
+    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);
+#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() { 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() {
+    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) {
+    return int_at(bci_cell_index(row));
+  }
+  uint bci_count(uint row) {
+    return uint_at(bci_count_cell_index(row));
+  }
+  int bci_displacement(uint row) {
+    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);
+#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() { return true; }
+
+  static int static_cell_count() {
+    return branch_cell_count;
+  }
+
+  virtual int cell_count() {
+    return static_cell_count();
+  }
+
+  // Direct accessor
+  uint not_taken() {
+    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);
+#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) {
+    int aindex = index + array_start_off_set;
+    return uint_at(aindex);
+  }
+  int array_int_at(int index) {
+    int aindex = index + array_start_off_set;
+    return int_at(aindex);
+  }
+  oop array_oop_at(int index) {
+    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() { return true; }
+
+  static int static_cell_count() {
+    return -1;
+  }
+
+  int array_len() {
+    return int_at_unchecked(array_len_off_set);
+  }
+
+  virtual int cell_count() {
+    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() { return true; }
+
+  static int compute_cell_count(BytecodeStream* stream);
+
+  int number_of_cases() {
+    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() {
+    return array_uint_at(default_count_off_set);
+  }
+  int default_displacement() {
+    return array_int_at(default_disaplacement_off_set);
+  }
+
+  uint count_at(int index) {
+    return array_uint_at(case_array_start +
+                         index * per_case_cell_count +
+                         relative_count_off_set);
+  }
+  int displacement_at(int index) {
+    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);
+#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() { return true; }
+
+
+  int number_of_args() {
+    return array_len();
+  }
+
+  uint arg_modified(int arg) {
+    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);
+#endif
+};
+
+// 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 {
+#ifdef GRAAL
+    _trap_hist_limit    = 13,   // decoupled from Deoptimization::Reason_LIMIT
+#else
+    _trap_hist_limit    = 17,   // decoupled from Deoptimization::Reason_LIMIT
+#endif
+    _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;
+
+  // 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();
+
+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;
+  }
+
+  // Perform initialization of a new MethodData*
+  void initialize(methodHandle method);
+
+  // My size
+  int size_in_bytes() const { return _size; }
+  int size() const    { return align_object_size(align_size_up(_size, BytesPerWord)/BytesPerWord); }
+
+  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()                    { return _highest_comp_level;      }
+  void set_highest_comp_level(int level)      { _highest_comp_level = level;     }
+  int highest_osr_comp_level()                { 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);
+  static bool is_empty_data(int size, Bytecodes::Code code);
+
+  // 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(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(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");
+    assert((uint)reason < _trap_hist_limit, "oob");
+    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);
+    }
+  }
+
+  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();
+
+  // Support for code generation
+  static ByteSize data_offset() {
+    return byte_offset_of(MethodData, _data[0]);
+  }
+
+  static ByteSize trap_history_offset() {
+    return byte_offset_of(MethodData, _trap_hist._array);
+  }
+
+  static ByteSize invocation_counter_offset() {
+    return byte_offset_of(MethodData, _invocation_counter);
+  }
+  static ByteSize backedge_counter_offset() {
+    return byte_offset_of(MethodData, _backedge_counter);
+  }
+
+  // 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);
+};
+
+#endif // SHARE_VM_OOPS_METHODDATAOOP_HPP