/*

 * 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

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#include "libadt/vectset.hpp"

#include "memory/resourceArea.hpp"

#include "opto/node.hpp"

#include "opto/phaseX.hpp"

#include "opto/regmask.hpp"

class Compile;

class Node;

class MachNode;

class MachTypeNode;

class MachOper;

//---------------------------Matcher-------------------------------------------

class Matcher : public PhaseTransform {

  friend class VMStructs;

public:

  // State and MStack class used in xform() and find_shared() iterative methods.

  enum Node_State { Pre_Visit,  // node has to be pre-visited

                    Visit,  // visit node

                    Post_Visit,  // post-visit node

                    Alt_Post_Visit   // alternative post-visit path

  };

  class MStack: public Node_Stack {

  public:

    MStack(int size) : Node_Stack(size) { }

    void push(Node *n, Node_State ns) {

      Node_Stack::push(n, (uint)ns);

    }

    void push(Node *n, Node_State ns, Node *parent, int indx) {

      ++_inode_top;

      if ((_inode_top + 1) >= _inode_max) grow();

      _inode_top->node = parent;

      _inode_top->indx = (uint)indx;

      ++_inode_top;

      _inode_top->node = n;

      _inode_top->indx = (uint)ns;

    }

    Node *parent() {

      pop();

      return node();

    }

    Node_State state() const {

      return (Node_State)index();

    }

    void set_state(Node_State ns) {

      set_index((uint)ns);

    }

  };

private:

  // Private arena of State objects

  ResourceArea _states_arena;

  VectorSet   _visited;         // Visit bits

  // Used to control the Label pass

  VectorSet   _shared;          // Shared Ideal Node

  VectorSet   _dontcare;        // Nothing the matcher cares about

  // Private methods which perform the actual matching and reduction

  // Walks the label tree, generating machine nodes

  MachNode *ReduceInst( State *s, int rule, Node *&mem);

  void ReduceInst_Chain_Rule( State *s, int rule, Node *&mem, MachNode *mach);

  uint ReduceInst_Interior(State *s, int rule, Node *&mem, MachNode *mach, uint num_opnds);

  void ReduceOper( State *s, int newrule, Node *&mem, MachNode *mach );

  // If this node already matched using "rule", return the MachNode for it.

  MachNode* find_shared_node(Node* n, uint rule);

  // Convert a dense opcode number to an expanded rule number

  const int *_reduceOp;

  const int *_leftOp;

  const int *_rightOp;

  // Map dense opcode number to info on when rule is swallowed constant.

  const bool *_swallowed;

  // Map dense rule number to determine if this is an instruction chain rule

  const uint _begin_inst_chain_rule;

  const uint _end_inst_chain_rule;

  // We want to clone constants and possible CmpI-variants.

  // If we do not clone CmpI, then we can have many instances of

  // condition codes alive at once.  This is OK on some chips and

  // bad on others.  Hence the machine-dependent table lookup.

  const char *_must_clone;

  // Find shared Nodes, or Nodes that otherwise are Matcher roots

  void find_shared( Node *n );

  bool find_shared_visit(MStack& mstack, Node* n, uint opcode, bool& mem_op, int& mem_addr_idx);

  void find_shared_post_visit(Node* n, uint opcode);

#ifdef X86

  bool is_bmi_pattern(Node *n, Node *m);

#endif

  // Debug and profile information for nodes in old space:

  GrowableArray<Node_Notes*>* _old_node_note_array;

  // Node labeling iterator for instruction selection

  Node *Label_Root( const Node *n, State *svec, Node *control, const Node *mem );

  Node *transform( Node *dummy );

  Node_List _projection_list;        // For Machine nodes killing many values

  Node_Array _shared_nodes;

  debug_only(Node_Array _old2new_map;)   // Map roots of ideal-trees to machine-roots

  debug_only(Node_Array _new2old_map;)   // Maps machine nodes back to ideal

  // Accessors for the inherited field PhaseTransform::_nodes:

  void   grow_new_node_array(uint idx_limit) {

    _nodes.map(idx_limit-1, NULL);

  }

  bool    has_new_node(const Node* n) const {

    return _nodes.at(n->_idx) != NULL;

  }

  Node*       new_node(const Node* n) const {

    assert(has_new_node(n), "set before get");

    return _nodes.at(n->_idx);

  }

  void    set_new_node(const Node* n, Node *nn) {

    assert(!has_new_node(n), "set only once");

    _nodes.map(n->_idx, nn);

  }

#ifdef ASSERT

  // Make sure only new nodes are reachable from this node

  void verify_new_nodes_only(Node* root);

  Node* _mem_node;   // Ideal memory node consumed by mach node

#endif

  // Mach node for ConP #NULL

  MachNode* _mach_null;

  void handle_precedence_edges(Node* n, MachNode *mach);

public:

  int LabelRootDepth;

  // Convert ideal machine register to a register mask for spill-loads

  static const RegMask *idealreg2regmask[];

  RegMask *idealreg2spillmask  [_last_machine_leaf];

  RegMask *idealreg2debugmask  [_last_machine_leaf];

  RegMask *idealreg2mhdebugmask[_last_machine_leaf];

  void init_spill_mask( Node *ret );

  // Convert machine register number to register mask

  static uint mreg2regmask_max;

  static RegMask mreg2regmask[];

  static RegMask STACK_ONLY_mask;

  MachNode* mach_null() const { return _mach_null; }

  bool    is_shared( Node *n ) { return _shared.test(n->_idx) != 0; }

  void   set_shared( Node *n ) {  _shared.set(n->_idx); }

  bool   is_visited( Node *n ) { return _visited.test(n->_idx) != 0; }

  void  set_visited( Node *n ) { _visited.set(n->_idx); }

  bool  is_dontcare( Node *n ) { return _dontcare.test(n->_idx) != 0; }

  void set_dontcare( Node *n ) {  _dontcare.set(n->_idx); }

  // Mode bit to tell DFA and expand rules whether we are running after

  // (or during) register selection.  Usually, the matcher runs before,

  // but it will also get called to generate post-allocation spill code.

  // In this situation, it is a deadly error to attempt to allocate more

  // temporary registers.

  bool _allocation_started;

  // Machine register names

  static const char *regName[];

  // Machine register encodings

  static const unsigned char _regEncode[];

  // Machine Node names

  const char **_ruleName;

  // Rules that are cheaper to rematerialize than to spill

  static const uint _begin_rematerialize;

  static const uint _end_rematerialize;

  // An array of chars, from 0 to _last_Mach_Reg.

  // No Save       = 'N' (for register windows)

  // Save on Entry = 'E'

  // Save on Call  = 'C'

  // Always Save   = 'A' (same as SOE + SOC)

  const char *_register_save_policy;

  const char *_c_reg_save_policy;

  // Convert a machine register to a machine register type, so-as to

  // properly match spill code.

  const int *_register_save_type;

  // Maps from machine register to boolean; true if machine register can

  // be holding a call argument in some signature.

  static bool can_be_java_arg( int reg );

  // Maps from machine register to boolean; true if machine register holds

  // a spillable argument.

  static bool is_spillable_arg( int reg );

  // List of IfFalse or IfTrue Nodes that indicate a taken null test.

  // List is valid in the post-matching space.

  Node_List _null_check_tests;

  void collect_null_checks( Node *proj, Node *orig_proj );

  void validate_null_checks( );

  Matcher();

  // Get a projection node at position pos

  Node* get_projection(uint pos) {

    return _projection_list[pos];

  }

  // Push a projection node onto the projection list

  void push_projection(Node* node) {

    _projection_list.push(node);

  }

  Node* pop_projection() {

    return _projection_list.pop();

  }

  // Number of nodes in the projection list

  uint number_of_projections() const {

    return _projection_list.size();

  }

  // Select instructions for entire method

  void match();

  // Helper for match

  OptoReg::Name warp_incoming_stk_arg( VMReg reg );

  // Transform, then walk.  Does implicit DCE while walking.

  // Name changed from "transform" to avoid it being virtual.

  Node *xform( Node *old_space_node, int Nodes );

  // Match a single Ideal Node - turn it into a 1-Node tree; Label & Reduce.

  MachNode *match_tree( const Node *n );

  MachNode *match_sfpt( SafePointNode *sfpt );

  // Helper for match_sfpt

  OptoReg::Name warp_outgoing_stk_arg( VMReg reg, OptoReg::Name begin_out_arg_area, OptoReg::Name &out_arg_limit_per_call );

  // Initialize first stack mask and related masks.

  void init_first_stack_mask();

  // If we should save-on-entry this register

  bool is_save_on_entry( int reg );

  // Fixup the save-on-entry registers

  void Fixup_Save_On_Entry( );

  // --- Frame handling ---

  // Register number of the stack slot corresponding to the incoming SP.

  // Per the Big Picture in the AD file, it is:

  //   SharedInfo::stack0 + locks + in_preserve_stack_slots + pad2.

  OptoReg::Name _old_SP;

  // Register number of the stack slot corresponding to the highest incoming

  // argument on the stack.  Per the Big Picture in the AD file, it is:

  //   _old_SP + out_preserve_stack_slots + incoming argument size.

  OptoReg::Name _in_arg_limit;

  // Register number of the stack slot corresponding to the new SP.

  // Per the Big Picture in the AD file, it is:

  //   _in_arg_limit + pad0

  OptoReg::Name _new_SP;

  // Register number of the stack slot corresponding to the highest outgoing

  // argument on the stack.  Per the Big Picture in the AD file, it is:

  //   _new_SP + max outgoing arguments of all calls

  OptoReg::Name _out_arg_limit;

  OptoRegPair *_parm_regs;        // Array of machine registers per argument

  RegMask *_calling_convention_mask; // Array of RegMasks per argument

  // Does matcher have a match rule for this ideal node?

  static const bool has_match_rule(int opcode);

  static const bool _hasMatchRule[_last_opcode];

  // Does matcher have a match rule for this ideal node and is the

  // predicate (if there is one) true?

  // NOTE: If this function is used more commonly in the future, ADLC

  // should generate this one.

  static const bool match_rule_supported(int opcode);

  // identify extra cases that we might want to provide match rules for

  // e.g. Op_ vector nodes and other intrinsics while guarding with vlen

  static const bool match_rule_supported_vector(int opcode, int vlen);

  // Some microarchitectures have mask registers used on vectors

  static const bool has_predicated_vectors(void);

  // Some uarchs have different sized float register resources

  static const int float_pressure(int default_pressure_threshold);

  // Used to determine if we have fast l2f conversion

  // USII has it, USIII doesn't

  static const bool convL2FSupported(void);

  // Vector width in bytes

  static const int vector_width_in_bytes(BasicType bt);

  // Limits on vector size (number of elements).

  static const int max_vector_size(const BasicType bt);

  static const int min_vector_size(const BasicType bt);

  static const bool vector_size_supported(const BasicType bt, int size) {

    return (Matcher::max_vector_size(bt) >= size &&

            Matcher::min_vector_size(bt) <= size);

  }

  // Vector ideal reg

  static const uint vector_ideal_reg(int len);

  static const uint vector_shift_count_ideal_reg(int len);

  // CPU supports misaligned vectors store/load.

  static const bool misaligned_vectors_ok();

  // Should original key array reference be passed to AES stubs

  static const bool pass_original_key_for_aes();

  // Used to determine a "low complexity" 64-bit constant.  (Zero is simple.)

  // The standard of comparison is one (StoreL ConL) vs. two (StoreI ConI).

  // Depends on the details of 64-bit constant generation on the CPU.

  static const bool isSimpleConstant64(jlong con);

  // These calls are all generated by the ADLC

  // TRUE - grows up, FALSE - grows down (Intel)

  virtual bool stack_direction() const;

  // Java-Java calling convention

  // (what you use when Java calls Java)

  // Alignment of stack in bytes, standard Intel word alignment is 4.

  // Sparc probably wants at least double-word (8).

  static uint stack_alignment_in_bytes();

  // Alignment of stack, measured in stack slots.

  // The size of stack slots is defined by VMRegImpl::stack_slot_size.

  static uint stack_alignment_in_slots() {

    return stack_alignment_in_bytes() / (VMRegImpl::stack_slot_size);

  }

  // Array mapping arguments to registers.  Argument 0 is usually the 'this'

  // pointer.  Registers can include stack-slots and regular registers.

  static void calling_convention( BasicType *, VMRegPair *, uint len, bool is_outgoing );

  // Convert a sig into a calling convention register layout

  // and find interesting things about it.

  static OptoReg::Name  find_receiver( bool is_outgoing );

  // Return address register.  On Intel it is a stack-slot.  On PowerPC

  // it is the Link register.  On Sparc it is r31?

  virtual OptoReg::Name return_addr() const;

  RegMask              _return_addr_mask;

  // Return value register.  On Intel it is EAX.  On Sparc i0/o0.

  static OptoRegPair   return_value(uint ideal_reg, bool is_outgoing);

  static OptoRegPair c_return_value(uint ideal_reg, bool is_outgoing);

  RegMask                     _return_value_mask;

  // Inline Cache Register

  static OptoReg::Name  inline_cache_reg();

  static int            inline_cache_reg_encode();

  // Register for DIVI projection of divmodI

  static RegMask divI_proj_mask();

  // Register for MODI projection of divmodI

  static RegMask modI_proj_mask();

  // Register for DIVL projection of divmodL

  static RegMask divL_proj_mask();

  // Register for MODL projection of divmodL

  static RegMask modL_proj_mask();

  // Use hardware DIV instruction when it is faster than

  // a code which use multiply for division by constant.

  static bool use_asm_for_ldiv_by_con( jlong divisor );

  static const RegMask method_handle_invoke_SP_save_mask();

  // Java-Interpreter calling convention

  // (what you use when calling between compiled-Java and Interpreted-Java

  // Number of callee-save + always-save registers

  // Ignores frame pointer and "special" registers

  static int  number_of_saved_registers();

  // The Method-klass-holder may be passed in the inline_cache_reg

  // and then expanded into the inline_cache_reg and a method_oop register

  static OptoReg::Name  interpreter_method_oop_reg();

  static int            interpreter_method_oop_reg_encode();

  static OptoReg::Name  compiler_method_oop_reg();

  static const RegMask &compiler_method_oop_reg_mask();

  static int            compiler_method_oop_reg_encode();

  // Interpreter's Frame Pointer Register

  static OptoReg::Name  interpreter_frame_pointer_reg();

  // Java-Native calling convention

  // (what you use when intercalling between Java and C++ code)

  // Array mapping arguments to registers.  Argument 0 is usually the 'this'

  // pointer.  Registers can include stack-slots and regular registers.

  static void c_calling_convention( BasicType*, VMRegPair *, uint );

  // Frame pointer. The frame pointer is kept at the base of the stack

  // and so is probably the stack pointer for most machines.  On Intel

  // it is ESP.  On the PowerPC it is R1.  On Sparc it is SP.

  OptoReg::Name  c_frame_pointer() const;

  static RegMask c_frame_ptr_mask;

  // !!!!! Special stuff for building ScopeDescs

  virtual int      regnum_to_fpu_offset(int regnum);

  // Is this branch offset small enough to be addressed by a short branch?

  bool is_short_branch_offset(int rule, int br_size, int offset);

  // Optional scaling for the parameter to the ClearArray/CopyArray node.

  static const bool init_array_count_is_in_bytes;

  // Some hardware needs 2 CMOV's for longs.

  static const int long_cmove_cost();

  // Some hardware have expensive CMOV for float and double.

  static const int float_cmove_cost();

  // Should the Matcher clone shifts on addressing modes, expecting them to

  // be subsumed into complex addressing expressions or compute them into

  // registers?  True for Intel but false for most RISCs

  bool clone_address_expressions(AddPNode* m, MStack& mstack, VectorSet& address_visited);

  // Clone base + offset address expression

  bool clone_base_plus_offset_address(AddPNode* m, MStack& mstack, VectorSet& address_visited);

  static bool narrow_oop_use_complex_address();

  static bool narrow_klass_use_complex_address();

  static bool const_oop_prefer_decode();

  static bool const_klass_prefer_decode();

  // Generate implicit null check for narrow oops if it can fold

  // into address expression (x64).

  //

  // [R12 + narrow_oop_reg<<3 + offset] // fold into address expression

  // NullCheck narrow_oop_reg

  //

  // When narrow oops can't fold into address expression (Sparc) and

  // base is not null use decode_not_null and normal implicit null check.

  // Note, decode_not_null node can be used here since it is referenced

  // only on non null path but it requires special handling, see

  // collect_null_checks():

  //

  // decode_not_null narrow_oop_reg, oop_reg // 'shift' and 'add base'

  // [oop_reg + offset]

  // NullCheck oop_reg

  //

  // With Zero base and when narrow oops can not fold into address

  // expression use normal implicit null check since only shift

  // is needed to decode narrow oop.

  //

  // decode narrow_oop_reg, oop_reg // only 'shift'

  // [oop_reg + offset]

  // NullCheck oop_reg

  //

  inline static bool gen_narrow_oop_implicit_null_checks() {

    // Advice matcher to perform null checks on the narrow oop side.

    // Implicit checks are not possible on the uncompressed oop side anyway

    // (at least not for read accesses).

    // Performs significantly better (especially on Power 6).

    if (!os::zero_page_read_protected()) {

      return true;

    }

    return Universe::narrow_oop_use_implicit_null_checks() &&

           (narrow_oop_use_complex_address() ||

            Universe::narrow_oop_base() != NULL);

  }

  // Is it better to copy float constants, or load them directly from memory?

  // Intel can load a float constant from a direct address, requiring no

  // extra registers.  Most RISCs will have to materialize an address into a

  // register first, so they may as well materialize the constant immediately.

  static const bool rematerialize_float_constants;

  // If CPU can load and store mis-aligned doubles directly then no fixup is

  // needed.  Else we split the double into 2 integer pieces and move it

  // piece-by-piece.  Only happens when passing doubles into C code or when