/*

 * Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

class Compile;

class Node;

class MachNode;

class MachTypeNode;

class MachOper;

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

class Matcher : public PhaseTransform {

  friend class VMStructs;

  // 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_constant(Node* con, 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 );

  // 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 &_proj_list;        // For Machine nodes killing many values

  Node_Array _shared_constants;

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

  // 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);

#endif

public:

  int LabelRootDepth;

  static const int base2reg[];        // Map Types to machine register types

  // 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];

  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;

  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 );

  void validate_null_checks( );

  Matcher( Node_List &proj_list );

  // 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 support this ideal node?

  static const bool has_match_rule(int opcode);

  static const bool _hasMatchRule[_last_opcode];

  // 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 uint vector_width_in_bytes(void);

  // Vector ideal reg

  static const uint vector_ideal_reg(void);

  // 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(int ideal_reg, bool is_outgoing);

  static OptoRegPair c_return_value(int ideal_reg, bool is_outgoing);

  RegMask                     _return_value_mask;

  // Inline Cache Register

  static OptoReg::Name  inline_cache_reg();

  static const RegMask &inline_cache_reg_mask();

  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();

  // 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 const RegMask &interpreter_method_oop_reg_mask();

  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();

  static const RegMask &interpreter_frame_pointer_reg_mask();

  // 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 offset);

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

  static const bool init_array_count_is_in_bytes;

  // Threshold small size (in bytes) for a ClearArray/CopyArray node.

  // Anything this size or smaller may get converted to discrete scalar stores.

  static const int init_array_short_size;

  // 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

  static const bool clone_shift_expressions;

  // 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

  // calling i2c adapters as the Java calling convention forces doubles to be

  // aligned.

  static const bool misaligned_doubles_ok;

  // Perform a platform dependent implicit null fixup.  This is needed

  // on windows95 to take care of some unusual register constraints.

  void pd_implicit_null_fixup(MachNode *load, uint idx);

  // Advertise here if the CPU requires explicit rounding operations

  // to implement the UseStrictFP mode.

  static const bool strict_fp_requires_explicit_rounding;

  // Do floats take an entire double register or just half?

  static const bool float_in_double;

  // Do ints take an entire long register or just half?

  static const bool int_in_long;

  // This routine is run whenever a graph fails to match.

  // If it returns, the compiler should bailout to interpreter without error.

  // In non-product mode, SoftMatchFailure is false to detect non-canonical

  // graphs.  Print a message and exit.

  static void soft_match_failure() {

    if( SoftMatchFailure ) return;

    else { fatal("SoftMatchFailure is not allowed except in product"); }

  }

  // Used by the DFA in dfa_sparc.cpp.  Check for a prior FastLock

  // acting as an Acquire and thus we don't need an Acquire here.  We

  // retain the Node to act as a compiler ordering barrier.

  static bool prior_fast_lock( const Node *acq );

  // Used by the DFA in dfa_sparc.cpp.  Check for a following

  // FastUnLock acting as a Release and thus we don't need a Release

  // here.  We retain the Node to act as a compiler ordering barrier.

  static bool post_fast_unlock( const Node *rel );

  // Check for a following volatile memory barrier without an

  // intervening load and thus we don't need a barrier here.  We

  // retain the Node to act as a compiler ordering barrier.

  static bool post_store_load_barrier(const Node* mb);

#ifdef ASSERT

  void dump_old2new_map();      // machine-independent to machine-dependent

#endif

};