/*

 * Copyright (c) 1997, 2017, 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_RUNTIME_DEOPTIMIZATION_HPP

#define SHARE_VM_RUNTIME_DEOPTIMIZATION_HPP

#include "memory/allocation.hpp"

#include "runtime/frame.inline.hpp"

class ProfileData;

class vframeArray;

class MonitorValue;

class ObjectValue;

class Deoptimization : AllStatic {

  friend class VMStructs;

 public:

  // What condition caused the deoptimization?

  enum DeoptReason {

    Reason_many = -1,             // indicates presence of several reasons

    Reason_none = 0,              // indicates absence of a relevant deopt.

    // Next 7 reasons are recorded per bytecode in DataLayout::trap_bits.

    // This is more complicated for JVMCI as JVMCI may deoptimize to *some* bytecode before the

    // bytecode that actually caused the deopt (with inlining, JVMCI may even deoptimize to a

    // bytecode in another method):

    //  - bytecode y in method b() causes deopt

    //  - JVMCI deoptimizes to bytecode x in method a()

    // -> the deopt reason will be recorded for method a() at bytecode x

    Reason_null_check,            // saw unexpected null or zero divisor (@bci)

    Reason_null_assert,           // saw unexpected non-null or non-zero (@bci)

    Reason_range_check,           // saw unexpected array index (@bci)

    Reason_class_check,           // saw unexpected object class (@bci)

    Reason_array_check,           // saw unexpected array class (aastore @bci)

    Reason_intrinsic,             // saw unexpected operand to intrinsic (@bci)

    Reason_bimorphic,             // saw unexpected object class in bimorphic inlining (@bci)

#if INCLUDE_JVMCI

    Reason_unreached0             = Reason_null_assert,

    Reason_type_checked_inlining  = Reason_intrinsic,

    Reason_optimized_type_check   = Reason_bimorphic,

#endif

    // recorded per method

    Reason_unloaded,              // unloaded class or constant pool entry

    Reason_uninitialized,         // bad class state (uninitialized)

    Reason_unreached,             // code is not reached, compiler

    Reason_unhandled,             // arbitrary compiler limitation

    Reason_constraint,            // arbitrary runtime constraint violated

    Reason_div0_check,            // a null_check due to division by zero

    Reason_age,                   // nmethod too old; tier threshold reached

    Reason_predicate,             // compiler generated predicate failed

    Reason_loop_limit_check,      // compiler generated loop limits check failed

    Reason_speculate_class_check, // saw unexpected object class from type speculation

    Reason_speculate_null_check,  // saw unexpected null from type speculation

    Reason_speculate_null_assert, // saw unexpected null from type speculation

    Reason_rtm_state_change,      // rtm state change detected

    Reason_unstable_if,           // a branch predicted always false was taken

    Reason_unstable_fused_if,     // fused two ifs that had each one untaken branch. One is now taken.

#if INCLUDE_JVMCI

    Reason_aliasing,              // optimistic assumption about aliasing failed

    Reason_transfer_to_interpreter, // explicit transferToInterpreter()

    Reason_not_compiled_exception_handler,

    Reason_unresolved,

    Reason_jsr_mismatch,

#endif

    // Reason_tenured is counted separately, add normal counted Reasons above.

    // Related to MethodData::_trap_hist_limit where Reason_tenured isn't included

    Reason_tenured,               // age of the code has reached the limit

    Reason_LIMIT,

    // Note:  Keep this enum in sync. with _trap_reason_name.

    Reason_RECORDED_LIMIT = Reason_bimorphic  // some are not recorded per bc

    // Note:  Reason_RECORDED_LIMIT should be < 8 to fit into 3 bits of

    // DataLayout::trap_bits.  This dependency is enforced indirectly

    // via asserts, to avoid excessive direct header-to-header dependencies.

    // See Deoptimization::trap_state_reason and class DataLayout.

  };

  // What action must be taken by the runtime?

  enum DeoptAction {

    Action_none,                  // just interpret, do not invalidate nmethod

    Action_maybe_recompile,       // recompile the nmethod; need not invalidate

    Action_reinterpret,           // invalidate the nmethod, reset IC, maybe recompile

    Action_make_not_entrant,      // invalidate the nmethod, recompile (probably)

    Action_make_not_compilable,   // invalidate the nmethod and do not compile

    Action_LIMIT

    // Note:  Keep this enum in sync. with _trap_action_name.

  };

  enum {

    _action_bits = 3,

    _reason_bits = 5,

    _debug_id_bits = 23,

    _action_shift = 0,

    _reason_shift = _action_shift+_action_bits,

    _debug_id_shift = _reason_shift+_reason_bits,

    BC_CASE_LIMIT = PRODUCT_ONLY(1) NOT_PRODUCT(4) // for _deoptimization_hist

  };

  enum UnpackType {

    Unpack_deopt                = 0, // normal deoptimization, use pc computed in unpack_vframe_on_stack

    Unpack_exception            = 1, // exception is pending

    Unpack_uncommon_trap        = 2, // redo last byte code (C2 only)

    Unpack_reexecute            = 3, // reexecute bytecode (C1 only)

    Unpack_LIMIT                = 4

  };

  // Checks all compiled methods. Invalid methods are deleted and

  // corresponding activations are deoptimized.

  static int deoptimize_dependents();

  // Deoptimizes a frame lazily. nmethod gets patched deopt happens on return to the frame

  static void deoptimize(JavaThread* thread, frame fr, RegisterMap *reg_map);

  static void deoptimize(JavaThread* thread, frame fr, RegisterMap *reg_map, DeoptReason reason);

#if INCLUDE_JVMCI

  static address deoptimize_for_missing_exception_handler(CompiledMethod* cm);

#endif

  private:

  // Does the actual work for deoptimizing a single frame

  static void deoptimize_single_frame(JavaThread* thread, frame fr, DeoptReason reason);

  // Helper function to revoke biases of all monitors in frame if UseBiasedLocking

  // is enabled

  static void revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map);

  // Helper function to revoke biases of all monitors in frames

  // executing in a particular CodeBlob if UseBiasedLocking is enabled

  static void revoke_biases_of_monitors(CodeBlob* cb);

#if defined(COMPILER2) || INCLUDE_JVMCI

JVMCI_ONLY(public:)

  // Support for restoring non-escaping objects

  static bool realloc_objects(JavaThread* thread, frame* fr, GrowableArray<ScopeValue*>* objects, TRAPS);

  static void reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type);

  static void reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj);

  static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects, bool realloc_failures, bool skip_internal);

  static void relock_objects(GrowableArray<MonitorInfo*>* monitors, JavaThread* thread, bool realloc_failures);

  static void pop_frames_failed_reallocs(JavaThread* thread, vframeArray* array);

  NOT_PRODUCT(static void print_objects(GrowableArray<ScopeValue*>* objects, bool realloc_failures);)

#endif // COMPILER2 || INCLUDE_JVMCI

  public:

  static vframeArray* create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk, bool realloc_failures);

  // Interface used for unpacking deoptimized frames

  // UnrollBlock is returned by fetch_unroll_info() to the deoptimization handler (blob).

  // This is only a CheapObj to ease debugging after a deopt failure

  class UnrollBlock : public CHeapObj<mtCompiler> {

    friend class VMStructs;

    friend class JVMCIVMStructs;

   private:

    int       _size_of_deoptimized_frame; // Size, in bytes, of current deoptimized frame

    int       _caller_adjustment;         // Adjustment, in bytes, to caller's SP by initial interpreted frame

    int       _number_of_frames;          // Number frames to unroll

    int       _total_frame_sizes;         // Total of number*sizes frames

    intptr_t* _frame_sizes;               // Array of frame sizes, in bytes, for unrolling the stack

    address*  _frame_pcs;                 // Array of frame pc's, in bytes, for unrolling the stack

    intptr_t* _register_block;            // Block for storing callee-saved registers.

    BasicType _return_type;               // Tells if we have to restore double or long return value

    intptr_t  _initial_info;              // Platform dependent data for the sender frame (was FP on x86)

    int       _caller_actual_parameters;  // The number of actual arguments at the

                                          // interpreted caller of the deoptimized frame

    int       _unpack_kind;               // exec_mode that can be changed during fetch_unroll_info

    // The following fields are used as temps during the unpacking phase

    // (which is tight on registers, especially on x86). They really ought

    // to be PD variables but that involves moving this class into its own

    // file to use the pd include mechanism. Maybe in a later cleanup ...

    intptr_t  _counter_temp;              // SHOULD BE PD VARIABLE (x86 frame count temp)

    intptr_t  _sender_sp_temp;            // SHOULD BE PD VARIABLE (x86 sender_sp)

   public:

    // Constructor

    UnrollBlock(int  size_of_deoptimized_frame,

                int  caller_adjustment,

                int  caller_actual_parameters,

                int  number_of_frames,

                intptr_t* frame_sizes,

                address* frames_pcs,

                BasicType return_type,

                int unpack_kind);

    ~UnrollBlock();

    // Returns where a register is located.

    intptr_t* value_addr_at(int register_number) const;

    // Accessors

    intptr_t* frame_sizes()  const { return _frame_sizes; }

    int number_of_frames()  const { return _number_of_frames; }

    address*  frame_pcs()   const { return _frame_pcs ; }

    int  unpack_kind()   const { return _unpack_kind; }

    // Returns the total size of frames

    int size_of_frames() const;

    void set_initial_info(intptr_t info) { _initial_info = info; }

    int caller_actual_parameters() const { return _caller_actual_parameters; }

    // Accessors used by the code generator for the unpack stub.

    static int size_of_deoptimized_frame_offset_in_bytes() { return offset_of(UnrollBlock, _size_of_deoptimized_frame); }

    static int caller_adjustment_offset_in_bytes()         { return offset_of(UnrollBlock, _caller_adjustment);         }

    static int number_of_frames_offset_in_bytes()          { return offset_of(UnrollBlock, _number_of_frames);          }

    static int frame_sizes_offset_in_bytes()               { return offset_of(UnrollBlock, _frame_sizes);               }

    static int total_frame_sizes_offset_in_bytes()         { return offset_of(UnrollBlock, _total_frame_sizes);         }

    static int frame_pcs_offset_in_bytes()                 { return offset_of(UnrollBlock, _frame_pcs);                 }

    static int register_block_offset_in_bytes()            { return offset_of(UnrollBlock, _register_block);            }

    static int return_type_offset_in_bytes()               { return offset_of(UnrollBlock, _return_type);               }

    static int counter_temp_offset_in_bytes()              { return offset_of(UnrollBlock, _counter_temp);              }

    static int initial_info_offset_in_bytes()              { return offset_of(UnrollBlock, _initial_info);              }

    static int unpack_kind_offset_in_bytes()               { return offset_of(UnrollBlock, _unpack_kind);               }

    static int sender_sp_temp_offset_in_bytes()            { return offset_of(UnrollBlock, _sender_sp_temp);            }

    BasicType return_type() const { return _return_type; }

    void print();

  };

  //** Returns an UnrollBlock continuing information

  // how to make room for the resulting interpreter frames.

  // Called by assembly stub after execution has returned to

  // deoptimized frame.

  // @argument thread.     Thread where stub_frame resides.

  // @see OptoRuntime::deoptimization_fetch_unroll_info_C

  static UnrollBlock* fetch_unroll_info(JavaThread* thread, int exec_mode);

  //** Unpacks vframeArray onto execution stack

  // Called by assembly stub after execution has returned to

  // deoptimized frame and after the stack unrolling.

  // @argument thread.     Thread where stub_frame resides.

  // @argument exec_mode.  Determines how execution should be continued in top frame.

  //                       0 means continue after current byte code

  //                       1 means exception has happened, handle exception

  //                       2 means reexecute current bytecode (for uncommon traps).

  // @see OptoRuntime::deoptimization_unpack_frames_C

  // Return BasicType of call return type, if any

  static BasicType unpack_frames(JavaThread* thread, int exec_mode);

  // Cleans up deoptimization bits on thread after unpacking or in the

  // case of an exception.

  static void cleanup_deopt_info(JavaThread  *thread,

                                 vframeArray * array);

  // Restores callee saved values from deoptimized frame into oldest interpreter frame

  // so caller of the deoptimized frame will get back the values it expects.

  static void unwind_callee_save_values(frame* f, vframeArray* vframe_array);

  //** Performs an uncommon trap for compiled code.

  // The top most compiler frame is converted into interpreter frames

  static UnrollBlock* uncommon_trap(JavaThread* thread, jint unloaded_class_index, jint exec_mode);

  // Helper routine that enters the VM and may block

  static void uncommon_trap_inner(JavaThread* thread, jint unloaded_class_index);

  //** Deoptimizes the frame identified by id.

  // Only called from VMDeoptimizeFrame

  // @argument thread.     Thread where stub_frame resides.

  // @argument id.         id of frame that should be deoptimized.

  static void deoptimize_frame_internal(JavaThread* thread, intptr_t* id, DeoptReason reason);

  // if thread is not the current thread then execute

  // VM_DeoptimizeFrame otherwise deoptimize directly.

  static void deoptimize_frame(JavaThread* thread, intptr_t* id, DeoptReason reason);

  static void deoptimize_frame(JavaThread* thread, intptr_t* id);

  // Statistics

  static void gather_statistics(DeoptReason reason, DeoptAction action,

                                Bytecodes::Code bc = Bytecodes::_illegal);

  static void print_statistics();

  // How much room to adjust the last frame's SP by, to make space for

  // the callee's interpreter frame (which expects locals to be next to

  // incoming arguments)

  static int last_frame_adjust(int callee_parameters, int callee_locals);

  // trap_request codes

  static DeoptReason trap_request_reason(int trap_request) {

    if (trap_request < 0)

      return (DeoptReason)

        ((~(trap_request) >> _reason_shift) & right_n_bits(_reason_bits));

    else

      // standard reason for unloaded CP entry

      return Reason_unloaded;

  }

  static DeoptAction trap_request_action(int trap_request) {

    if (trap_request < 0)

      return (DeoptAction)

        ((~(trap_request) >> _action_shift) & right_n_bits(_action_bits));

    else

      // standard action for unloaded CP entry

      return _unloaded_action;

  }

  static int trap_request_debug_id(int trap_request) {

    if (trap_request < 0) {

      return ((~(trap_request) >> _debug_id_shift) & right_n_bits(_debug_id_bits));

    } else {

      // standard action for unloaded CP entry

      return 0;

    }

  }

  static int trap_request_index(int trap_request) {

    if (trap_request < 0)

      return -1;

    else

      return trap_request;

  }

  static int make_trap_request(DeoptReason reason, DeoptAction action,

                               int index = -1) {

    assert((1 << _reason_bits) >= Reason_LIMIT, "enough bits");

    assert((1 << _action_bits) >= Action_LIMIT, "enough bits");

    int trap_request;

    if (index != -1)

      trap_request = index;

    else

      trap_request = (~(((reason) << _reason_shift)

                        + ((action) << _action_shift)));

    assert(reason == trap_request_reason(trap_request), "valid reason");

    assert(action == trap_request_action(trap_request), "valid action");

    assert(index  == trap_request_index(trap_request),  "valid index");

    return trap_request;

  }

  // The trap_state stored in a MDO is decoded here.

  // It records two items of information.

  //  reason:  If a deoptimization happened here, what its reason was,

  //           or if there were multiple deopts with differing reasons.

  //  recompiled: If a deoptimization here triggered a recompilation.

  // Note that not all reasons are recorded per-bci.

  static DeoptReason trap_state_reason(int trap_state);

  static int  trap_state_has_reason(int trap_state, int reason);

  static int  trap_state_add_reason(int trap_state, int reason);

  static bool trap_state_is_recompiled(int trap_state);

  static int  trap_state_set_recompiled(int trap_state, bool z);

  static const char* format_trap_state(char* buf, size_t buflen,

                                       int trap_state);

  static bool reason_is_recorded_per_bytecode(DeoptReason reason) {

    return reason > Reason_none && reason <= Reason_RECORDED_LIMIT;

  }

  static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {

    if (reason_is_recorded_per_bytecode(reason))

      return reason;

    else if (reason == Reason_div0_check) // null check due to divide-by-zero?

      return Reason_null_check;           // recorded per BCI as a null check

    else if (reason == Reason_speculate_class_check)

      return Reason_class_check;

    else if (reason == Reason_speculate_null_check)

      return Reason_null_check;

    else if (reason == Reason_speculate_null_assert)

      return Reason_null_assert;

    else if (reason == Reason_unstable_if)

      return Reason_intrinsic;

    else if (reason == Reason_unstable_fused_if)

      return Reason_range_check;

    else

      return Reason_none;

  }

  static bool reason_is_speculate(int reason) {

    if (reason == Reason_speculate_class_check ||

        reason == Reason_speculate_null_check ||

        reason == Reason_speculate_null_assert) {

      return true;

    }

    return false;

  }

  static DeoptReason reason_null_check(bool speculative) {

    return speculative ? Deoptimization::Reason_speculate_null_check : Deoptimization::Reason_null_check;

  }

  static DeoptReason reason_class_check(bool speculative) {

    return speculative ? Deoptimization::Reason_speculate_class_check : Deoptimization::Reason_class_check;

  }

  static DeoptReason reason_null_assert(bool speculative) {

    return speculative ? Deoptimization::Reason_speculate_null_assert : Deoptimization::Reason_null_assert;

  }

  static uint per_method_trap_limit(int reason) {

    return reason_is_speculate(reason) ? (uint)PerMethodSpecTrapLimit : (uint)PerMethodTrapLimit;

  }

  static const char* trap_reason_name(int reason);

  static const char* trap_action_name(int action);

  // Format like reason='foo' action='bar' index='123'.

  // This is suitable both for XML and for tty output.

  static const char* format_trap_request(char* buf, size_t buflen,

                                         int trap_request);

  static jint total_deoptimization_count();

  static jint deoptimization_count(DeoptReason reason);

  // JVMTI PopFrame support

  // Preserves incoming arguments to the popped frame when it is

  // returning to a deoptimized caller

  static void popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address);

  static MethodData* get_method_data(JavaThread* thread, const methodHandle& m, bool create_if_missing);

 private:

  // Update the mdo's count and per-BCI reason bits, returning previous state:

  static ProfileData* query_update_method_data(MethodData* trap_mdo,

                                               int trap_bci,

                                               DeoptReason reason,

                                               bool update_total_trap_count,

#if INCLUDE_JVMCI

                                               bool is_osr,

#endif

                                               Method* compiled_method,

                                               //outputs:

                                               uint& ret_this_trap_count,

                                               bool& ret_maybe_prior_trap,

                                               bool& ret_maybe_prior_recompile);

  // class loading support for uncommon trap

  static void load_class_by_index(const constantPoolHandle& constant_pool, int index, TRAPS);

  static void load_class_by_index(const constantPoolHandle& constant_pool, int index);

  static UnrollBlock* fetch_unroll_info_helper(JavaThread* thread, int exec_mode);

  static DeoptAction _unloaded_action; // == Action_reinterpret;

  static const char* _trap_reason_name[];

  static const char* _trap_action_name[];

  static juint _deoptimization_hist[Reason_LIMIT][1+Action_LIMIT][BC_CASE_LIMIT];

  // Note:  Histogram array size is 1-2 Kb.

 public:

  static void update_method_data_from_interpreter(MethodData* trap_mdo, int trap_bci, int reason);

};

class DeoptimizationMarker : StackObj {  // for profiling

  static bool _is_active;

public:

  DeoptimizationMarker()  { _is_active = true; }

  ~DeoptimizationMarker() { _is_active = false; }

  static bool is_active() { return _is_active; }

};

#endif // SHARE_VM_RUNTIME_DEOPTIMIZATION_HPP