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 /*

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  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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  * 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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  */

 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_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 );

   // 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_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;

 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];

   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( 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 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);

   // 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();

   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 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 rule, 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;

   static bool narrow_oop_use_complex_address();

   // 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() {

     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

   // 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;

   // Are floats conerted to double when stored to stack during deoptimization?

   static 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

   Node* find_old_node(Node* new_node) {

     return _new2old_map[new_node->_idx];

   }

 #endif

 };