jdk8-mips64-public/hotspot: src/share/vm/opto/block.hpp@f90c822e73f8 (annotated)

src/share/vm/opto/block.hpp@f90c822e73f8 (annotated)

src/share/vm/opto/block.hpp

Wed, 27 Apr 2016 01:25:04 +0800

author: aoqi
date: Wed, 27 Apr 2016 01:25:04 +0800
changeset 0: f90c822e73f8
child 6876: 710a3c8b516e
permissions: -rw-r--r--

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changeset: 6782:28b50d07f6f8
tag: jdk8u25-b17

 /*
  * Copyright (c) 1997, 2013, 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_OPTO_BLOCK_HPP
 #define SHARE_VM_OPTO_BLOCK_HPP
 #include "opto/multnode.hpp"
 #include "opto/node.hpp"
 #include "opto/phase.hpp"
 // Optimization - Graph Style
 class Block;
 class CFGLoop;
 class MachCallNode;
 class Matcher;
 class RootNode;
 class VectorSet;
 struct Tarjan;
 //------------------------------Block_Array------------------------------------
 // Map dense integer indices to Blocks.  Uses classic doubling-array trick.
 // Abstractly provides an infinite array of Block*'s, initialized to NULL.
 // Note that the constructor just zeros things, and since I use Arena
 // allocation I do not need a destructor to reclaim storage.
 class Block_Array : public ResourceObj {
   friend class VMStructs;
   uint _size;                   // allocated size, as opposed to formal limit
   debug_only(uint _limit;)      // limit to formal domain
   Arena *_arena;                // Arena to allocate in
 protected:
   Block **_blocks;
   void grow( uint i );          // Grow array node to fit
 public:
   Block_Array(Arena *a) : _arena(a), _size(OptoBlockListSize) {
     debug_only(_limit=0);
     _blocks = NEW_ARENA_ARRAY( a, Block *, OptoBlockListSize );
     for( int i = 0; i < OptoBlockListSize; i++ ) {
       _blocks[i] = NULL;
     }
   }
   Block *lookup( uint i ) const // Lookup, or NULL for not mapped
   { return (i<Max()) ? _blocks[i] : (Block*)NULL; }
   Block *operator[] ( uint i ) const // Lookup, or assert for not mapped
   { assert( i < Max(), "oob" ); return _blocks[i]; }
   // Extend the mapping: index i maps to Block *n.
   void map( uint i, Block *n ) { if( i>=Max() ) grow(i); _blocks[i] = n; }
   uint Max() const { debug_only(return _limit); return _size; }
 };
 class Block_List : public Block_Array {
   friend class VMStructs;
 public:
   uint _cnt;
   Block_List() : Block_Array(Thread::current()->resource_area()), _cnt(0) {}
   void push( Block *b ) {  map(_cnt++,b); }
   Block *pop() { return _blocks[--_cnt]; }
   Block *rpop() { Block *b = _blocks[0]; _blocks[0]=_blocks[--_cnt]; return b;}
   void remove( uint i );
   void insert( uint i, Block *n );
   uint size() const { return _cnt; }
   void reset() { _cnt = 0; }
   void print();
 };
 class CFGElement : public ResourceObj {
   friend class VMStructs;
  public:
   float _freq; // Execution frequency (estimate)
   CFGElement() : _freq(0.0f) {}
   virtual bool is_block() { return false; }
   virtual bool is_loop()  { return false; }
   Block*   as_Block() { assert(is_block(), "must be block"); return (Block*)this; }
   CFGLoop* as_CFGLoop()  { assert(is_loop(),  "must be loop");  return (CFGLoop*)this;  }
 };
 //------------------------------Block------------------------------------------
 // This class defines a Basic Block.
 // Basic blocks are used during the output routines, and are not used during
 // any optimization pass.  They are created late in the game.
 class Block : public CFGElement {
   friend class VMStructs;
 private:
   // Nodes in this block, in order
   Node_List _nodes;
 public:
   // Get the node at index 'at_index', if 'at_index' is out of bounds return NULL
   Node* get_node(uint at_index) const {
     return _nodes[at_index];
   }
   // Get the number of nodes in this block
   uint number_of_nodes() const {
     return _nodes.size();
   }
   // Map a node 'node' to index 'to_index' in the block, if the index is out of bounds the size of the node list is increased
   void map_node(Node* node, uint to_index) {
     _nodes.map(to_index, node);
   }
   // Insert a node 'node' at index 'at_index', moving all nodes that are on a higher index one step, if 'at_index' is out of bounds we crash
   void insert_node(Node* node, uint at_index) {
     _nodes.insert(at_index, node);
   }
   // Remove a node at index 'at_index'
   void remove_node(uint at_index) {
     _nodes.remove(at_index);
   }
   // Push a node 'node' onto the node list
   void push_node(Node* node) {
     _nodes.push(node);
   }
   // Pop the last node off the node list
   Node* pop_node() {
     return _nodes.pop();
   }
   // Basic blocks have a Node which defines Control for all Nodes pinned in
   // this block.  This Node is a RegionNode.  Exception-causing Nodes
   // (division, subroutines) and Phi functions are always pinned.  Later,
   // every Node will get pinned to some block.
   Node *head() const { return get_node(0); }
   // CAUTION: num_preds() is ONE based, so that predecessor numbers match
   // input edges to Regions and Phis.
   uint num_preds() const { return head()->req(); }
   Node *pred(uint i) const { return head()->in(i); }
   // Array of successor blocks, same size as projs array
   Block_Array _succs;
   // Basic blocks have some number of Nodes which split control to all
   // following blocks.  These Nodes are always Projections.  The field in
   // the Projection and the block-ending Node determine which Block follows.
   uint _num_succs;
   // Basic blocks also carry all sorts of good old fashioned DFS information
   // used to find loops, loop nesting depth, dominators, etc.
   uint _pre_order;              // Pre-order DFS number
   // Dominator tree
   uint _dom_depth;              // Depth in dominator tree for fast LCA
   Block* _idom;                 // Immediate dominator block
   CFGLoop *_loop;               // Loop to which this block belongs
   uint _rpo;                    // Number in reverse post order walk
   virtual bool is_block() { return true; }
   float succ_prob(uint i);      // return probability of i'th successor
   int num_fall_throughs();      // How many fall-through candidate this block has
   void update_uncommon_branch(Block* un); // Lower branch prob to uncommon code
   bool succ_fall_through(uint i); // Is successor "i" is a fall-through candidate
   Block* lone_fall_through();   // Return lone fall-through Block or null
   Block* dom_lca(Block* that);  // Compute LCA in dominator tree.
 #ifdef ASSERT
   bool dominates(Block* that) {
     int dom_diff = this->_dom_depth - that->_dom_depth;
     if (dom_diff > 0)  return false;
     for (; dom_diff < 0; dom_diff++)  that = that->_idom;
     return this == that;
   }
 #endif
   // Report the alignment required by this block.  Must be a power of 2.
   // The previous block will insert nops to get this alignment.
   uint code_alignment();
   uint compute_loop_alignment();
   // BLOCK_FREQUENCY is a sentinel to mark uses of constant block frequencies.
   // It is currently also used to scale such frequencies relative to
   // FreqCountInvocations relative to the old value of 1500.
 #define BLOCK_FREQUENCY(f) ((f * (float) 1500) / FreqCountInvocations)
   // Register Pressure (estimate) for Splitting heuristic
   uint _reg_pressure;
   uint _ihrp_index;
   uint _freg_pressure;
   uint _fhrp_index;
   // Mark and visited bits for an LCA calculation in insert_anti_dependences.
   // Since they hold unique node indexes, they do not need reinitialization.
   node_idx_t _raise_LCA_mark;
   void    set_raise_LCA_mark(node_idx_t x)    { _raise_LCA_mark = x; }
   node_idx_t  raise_LCA_mark() const          { return _raise_LCA_mark; }
   node_idx_t _raise_LCA_visited;
   void    set_raise_LCA_visited(node_idx_t x) { _raise_LCA_visited = x; }
   node_idx_t  raise_LCA_visited() const       { return _raise_LCA_visited; }
   // Estimated size in bytes of first instructions in a loop.
   uint _first_inst_size;
   uint first_inst_size() const     { return _first_inst_size; }
   void set_first_inst_size(uint s) { _first_inst_size = s; }
   // Compute the size of first instructions in this block.
   uint compute_first_inst_size(uint& sum_size, uint inst_cnt, PhaseRegAlloc* ra);
   // Compute alignment padding if the block needs it.
   // Align a loop if loop's padding is less or equal to padding limit
   // or the size of first instructions in the loop > padding.
   uint alignment_padding(int current_offset) {
     int block_alignment = code_alignment();
     int max_pad = block_alignment-relocInfo::addr_unit();
     if( max_pad > 0 ) {
       assert(is_power_of_2(max_pad+relocInfo::addr_unit()), "");
       int current_alignment = current_offset & max_pad;
       if( current_alignment != 0 ) {
         uint padding = (block_alignment-current_alignment) & max_pad;
         if( has_loop_alignment() &&
             padding > (uint)MaxLoopPad &&
             first_inst_size() <= padding ) {
           return 0;
         }
         return padding;
       }
     }
     return 0;
   }
   // Connector blocks. Connector blocks are basic blocks devoid of
   // instructions, but may have relevant non-instruction Nodes, such as
   // Phis or MergeMems. Such blocks are discovered and marked during the
   // RemoveEmpty phase, and elided during Output.
   bool _connector;
   void set_connector() { _connector = true; }
   bool is_connector() const { return _connector; };
   // Loop_alignment will be set for blocks which are at the top of loops.
   // The block layout pass may rotate loops such that the loop head may not
   // be the sequentially first block of the loop encountered in the linear
   // list of blocks.  If the layout pass is not run, loop alignment is set
   // for each block which is the head of a loop.
   uint _loop_alignment;
   void set_loop_alignment(Block *loop_top) {
     uint new_alignment = loop_top->compute_loop_alignment();
     if (new_alignment > _loop_alignment) {
       _loop_alignment = new_alignment;
     }
   }
   uint loop_alignment() const { return _loop_alignment; }
   bool has_loop_alignment() const { return loop_alignment() > 0; }
   // Create a new Block with given head Node.
   // Creates the (empty) predecessor arrays.
   Block( Arena *a, Node *headnode )
     : CFGElement(),
       _nodes(a),
       _succs(a),
       _num_succs(0),
       _pre_order(0),
       _idom(0),
       _loop(NULL),
       _reg_pressure(0),
       _ihrp_index(1),
       _freg_pressure(0),
       _fhrp_index(1),
       _raise_LCA_mark(0),
       _raise_LCA_visited(0),
       _first_inst_size(999999),
       _connector(false),
       _loop_alignment(0) {
     _nodes.push(headnode);
   }
   // Index of 'end' Node
   uint end_idx() const {
     // %%%%% add a proj after every goto
     // so (last->is_block_proj() != last) always, then simplify this code
     // This will not give correct end_idx for block 0 when it only contains root.
     int last_idx = _nodes.size() - 1;
     Node *last  = _nodes[last_idx];
     assert(last->is_block_proj() == last || last->is_block_proj() == _nodes[last_idx - _num_succs], "");
     return (last->is_block_proj() == last) ? last_idx : (last_idx - _num_succs);
   }
   // Basic blocks have a Node which ends them.  This Node determines which
   // basic block follows this one in the program flow.  This Node is either an
   // IfNode, a GotoNode, a JmpNode, or a ReturnNode.
   Node *end() const { return _nodes[end_idx()]; }
   // Add an instruction to an existing block.  It must go after the head
   // instruction and before the end instruction.
   void add_inst( Node *n ) { insert_node(n, end_idx()); }
   // Find node in block. Fails if node not in block.
   uint find_node( const Node *n ) const;
   // Find and remove n from block list
   void find_remove( const Node *n );
   // Check wether the node is in the block.
   bool contains (const Node *n) const;
   // Return the empty status of a block
   enum { not_empty, empty_with_goto, completely_empty };
   int is_Empty() const;
   // Forward through connectors
   Block* non_connector() {
     Block* s = this;
     while (s->is_connector()) {
       s = s->_succs[0];
     }
     return s;
   }
   // Return true if b is a successor of this block
   bool has_successor(Block* b) const {
     for (uint i = 0; i < _num_succs; i++ ) {
       if (non_connector_successor(i) == b) {
         return true;
       }
     }
     return false;
   }
   // Successor block, after forwarding through connectors
   Block* non_connector_successor(int i) const {
     return _succs[i]->non_connector();
   }
   // Examine block's code shape to predict if it is not commonly executed.
   bool has_uncommon_code() const;
 #ifndef PRODUCT
   // Debugging print of basic block
   void dump_bidx(const Block* orig, outputStream* st = tty) const;
   void dump_pred(const PhaseCFG* cfg, Block* orig, outputStream* st = tty) const;
   void dump_head(const PhaseCFG* cfg, outputStream* st = tty) const;
   void dump() const;
   void dump(const PhaseCFG* cfg) const;
 #endif
 };
 //------------------------------PhaseCFG---------------------------------------
 // Build an array of Basic Block pointers, one per Node.
 class PhaseCFG : public Phase {
   friend class VMStructs;
  private:
   // Root of whole program
   RootNode* _root;
   // The block containing the root node
   Block* _root_block;
   // List of basic blocks that are created during CFG creation
   Block_List _blocks;
   // Count of basic blocks
   uint _number_of_blocks;
   // Arena for the blocks to be stored in
   Arena* _block_arena;
   // The matcher for this compilation
   Matcher& _matcher;
   // Map nodes to owning basic block
   Block_Array _node_to_block_mapping;
   // Loop from the root
   CFGLoop* _root_loop;
   // Outmost loop frequency
   float _outer_loop_frequency;
   // Per node latency estimation, valid only during GCM
   GrowableArray<uint>* _node_latency;
   // Build a proper looking cfg.  Return count of basic blocks
   uint build_cfg();
   // Build the dominator tree so that we know where we can move instructions
   void build_dominator_tree();
   // Estimate block frequencies based on IfNode probabilities, so that we know where we want to move instructions
   void estimate_block_frequency();
   // Global Code Motion.  See Click's PLDI95 paper.  Place Nodes in specific
   // basic blocks; i.e. _node_to_block_mapping now maps _idx for all Nodes to some Block.
   // Move nodes to ensure correctness from GVN and also try to move nodes out of loops.
   void global_code_motion();
   // Schedule Nodes early in their basic blocks.
   bool schedule_early(VectorSet &visited, Node_List &roots);
   // For each node, find the latest block it can be scheduled into
   // and then select the cheapest block between the latest and earliest
   // block to place the node.
   void schedule_late(VectorSet &visited, Node_List &stack);
   // Compute the (backwards) latency of a node from a single use
   int latency_from_use(Node *n, const Node *def, Node *use);
   // Compute the (backwards) latency of a node from the uses of this instruction
   void partial_latency_of_defs(Node *n);
   // Compute the instruction global latency with a backwards walk
   void compute_latencies_backwards(VectorSet &visited, Node_List &stack);
   // Pick a block between early and late that is a cheaper alternative
   // to late. Helper for schedule_late.
   Block* hoist_to_cheaper_block(Block* LCA, Block* early, Node* self);
   bool schedule_local(Block* block, GrowableArray<int>& ready_cnt, VectorSet& next_call);
   void set_next_call(Block* block, Node* n, VectorSet& next_call);
   void needed_for_next_call(Block* block, Node* this_call, VectorSet& next_call);
   // Perform basic-block local scheduling
   Node* select(Block* block, Node_List& worklist, GrowableArray<int>& ready_cnt, VectorSet& next_call, uint sched_slot);
   // Schedule a call next in the block
   uint sched_call(Block* block, uint node_cnt, Node_List& worklist, GrowableArray<int>& ready_cnt, MachCallNode* mcall, VectorSet& next_call);
   // Cleanup if any code lands between a Call and his Catch
   void call_catch_cleanup(Block* block);
   Node* catch_cleanup_find_cloned_def(Block* use_blk, Node* def, Block* def_blk, int n_clone_idx);
   void  catch_cleanup_inter_block(Node *use, Block *use_blk, Node *def, Block *def_blk, int n_clone_idx);
   // Detect implicit-null-check opportunities.  Basically, find NULL checks
   // with suitable memory ops nearby.  Use the memory op to do the NULL check.
   // I can generate a memory op if there is not one nearby.
   void implicit_null_check(Block* block, Node *proj, Node *val, int allowed_reasons);
   // Perform a Depth First Search (DFS).
   // Setup 'vertex' as DFS to vertex mapping.
   // Setup 'semi' as vertex to DFS mapping.
   // Set 'parent' to DFS parent.
   uint do_DFS(Tarjan* tarjan, uint rpo_counter);
   // Helper function to insert a node into a block
   void schedule_node_into_block( Node *n, Block *b );
   void replace_block_proj_ctrl( Node *n );
   // Set the basic block for pinned Nodes
   void schedule_pinned_nodes( VectorSet &visited );
   // I'll need a few machine-specific GotoNodes.  Clone from this one.
   // Used when building the CFG and creating end nodes for blocks.
   MachNode* _goto;
   Block* insert_anti_dependences(Block* LCA, Node* load, bool verify = false);
   void verify_anti_dependences(Block* LCA, Node* load) {
     assert(LCA == get_block_for_node(load), "should already be scheduled");
     insert_anti_dependences(LCA, load, true);
   }
   bool move_to_next(Block* bx, uint b_index);
   void move_to_end(Block* bx, uint b_index);
   void insert_goto_at(uint block_no, uint succ_no);
   // Check for NeverBranch at block end.  This needs to become a GOTO to the
   // true target.  NeverBranch are treated as a conditional branch that always
   // goes the same direction for most of the optimizer and are used to give a
   // fake exit path to infinite loops.  At this late stage they need to turn
   // into Goto's so that when you enter the infinite loop you indeed hang.
   void convert_NeverBranch_to_Goto(Block *b);
   CFGLoop* create_loop_tree();
   #ifndef PRODUCT
   bool _trace_opto_pipelining;  // tracing flag
   #endif
  public:
   PhaseCFG(Arena* arena, RootNode* root, Matcher& matcher);
   void set_latency_for_node(Node* node, int latency) {
     _node_latency->at_put_grow(node->_idx, latency);
   }
   uint get_latency_for_node(Node* node) {
     return _node_latency->at_grow(node->_idx);
   }
   // Get the outer most frequency
   float get_outer_loop_frequency() const {
     return _outer_loop_frequency;
   }
   // Get the root node of the CFG
   RootNode* get_root_node() const {
     return _root;
   }
   // Get the block of the root node
   Block* get_root_block() const {
     return _root_block;
   }
   // Add a block at a position and moves the later ones one step
   void add_block_at(uint pos, Block* block) {
     _blocks.insert(pos, block);
     _number_of_blocks++;
   }
   // Adds a block to the top of the block list
   void add_block(Block* block) {
     _blocks.push(block);
     _number_of_blocks++;
   }
   // Clear the list of blocks
   void clear_blocks() {
     _blocks.reset();
     _number_of_blocks = 0;
   }
   // Get the block at position pos in _blocks
   Block* get_block(uint pos) const {
     return _blocks[pos];
   }
   // Number of blocks
   uint number_of_blocks() const {
     return _number_of_blocks;
   }
   // set which block this node should reside in
   void map_node_to_block(const Node* node, Block* block) {
     _node_to_block_mapping.map(node->_idx, block);
   }
   // removes the mapping from a node to a block
   void unmap_node_from_block(const Node* node) {
     _node_to_block_mapping.map(node->_idx, NULL);
   }
   // get the block in which this node resides
   Block* get_block_for_node(const Node* node) const {
     return _node_to_block_mapping[node->_idx];
   }
   // does this node reside in a block; return true
   bool has_block(const Node* node) const {
     return (_node_to_block_mapping.lookup(node->_idx) != NULL);
   }
   // Use frequency calculations and code shape to predict if the block
   // is uncommon.
   bool is_uncommon(const Block* block);
 #ifdef ASSERT
   Unique_Node_List _raw_oops;
 #endif
   // Do global code motion by first building dominator tree and estimate block frequency
   // Returns true on success
   bool do_global_code_motion();
   // Compute the (backwards) latency of a node from the uses
   void latency_from_uses(Node *n);
   // Set loop alignment
   void set_loop_alignment();
   // Remove empty basic blocks
   void remove_empty_blocks();
   Block *fixup_trap_based_check(Node *branch, Block *block, int block_pos, Block *bnext);
   void fixup_flow();
   // Insert a node into a block at index and map the node to the block
   void insert(Block *b, uint idx, Node *n) {
     b->insert_node(n , idx);
     map_node_to_block(n, b);
   }
   // Check all nodes and postalloc_expand them if necessary.
   void postalloc_expand(PhaseRegAlloc* _ra);
 #ifndef PRODUCT
   bool trace_opto_pipelining() const { return _trace_opto_pipelining; }
   // Debugging print of CFG
   void dump( ) const;           // CFG only
   void _dump_cfg( const Node *end, VectorSet &visited  ) const;
   void verify() const;
   void dump_headers();
 #else
   bool trace_opto_pipelining() const { return false; }
 #endif
 };
 //------------------------------UnionFind--------------------------------------
 // Map Block indices to a block-index for a cfg-cover.
 // Array lookup in the optimized case.
 class UnionFind : public ResourceObj {
   uint _cnt, _max;
   uint* _indices;
   ReallocMark _nesting;  // assertion check for reallocations
 public:
   UnionFind( uint max );
   void reset( uint max );  // Reset to identity map for [0..max]
   uint lookup( uint nidx ) const {
     return _indices[nidx];
   }
   uint operator[] (uint nidx) const { return lookup(nidx); }
   void map( uint from_idx, uint to_idx ) {
     assert( from_idx < _cnt, "oob" );
     _indices[from_idx] = to_idx;
   }
   void extend( uint from_idx, uint to_idx );
   uint Size() const { return _cnt; }
   uint Find( uint idx ) {
     assert( idx < 65536, "Must fit into uint");
     uint uf_idx = lookup(idx);
     return (uf_idx == idx) ? uf_idx : Find_compress(idx);
   }
   uint Find_compress( uint idx );
   uint Find_const( uint idx ) const;
   void Union( uint idx1, uint idx2 );
 };
 //----------------------------BlockProbPair---------------------------
 // Ordered pair of Node*.
 class BlockProbPair VALUE_OBJ_CLASS_SPEC {
 protected:
   Block* _target;      // block target
   float  _prob;        // probability of edge to block
 public:
   BlockProbPair() : _target(NULL), _prob(0.0) {}
   BlockProbPair(Block* b, float p) : _target(b), _prob(p) {}
   Block* get_target() const { return _target; }
   float get_prob() const { return _prob; }
 };
 //------------------------------CFGLoop-------------------------------------------
 class CFGLoop : public CFGElement {
   friend class VMStructs;
   int _id;
   int _depth;
   CFGLoop *_parent;      // root of loop tree is the method level "pseudo" loop, it's parent is null
   CFGLoop *_sibling;     // null terminated list
   CFGLoop *_child;       // first child, use child's sibling to visit all immediately nested loops
   GrowableArray<CFGElement*> _members; // list of members of loop
   GrowableArray<BlockProbPair> _exits; // list of successor blocks and their probabilities
   float _exit_prob;       // probability any loop exit is taken on a single loop iteration
   void update_succ_freq(Block* b, float freq);
  public:
   CFGLoop(int id) :
     CFGElement(),
     _id(id),
     _depth(0),
     _parent(NULL),
     _sibling(NULL),
     _child(NULL),
     _exit_prob(1.0f) {}
   CFGLoop* parent() { return _parent; }
   void push_pred(Block* blk, int i, Block_List& worklist, PhaseCFG* cfg);
   void add_member(CFGElement *s) { _members.push(s); }
   void add_nested_loop(CFGLoop* cl);
   Block* head() {
     assert(_members.at(0)->is_block(), "head must be a block");
     Block* hd = _members.at(0)->as_Block();
     assert(hd->_loop == this, "just checking");
     assert(hd->head()->is_Loop(), "must begin with loop head node");
     return hd;
   }
   Block* backedge_block(); // Return the block on the backedge of the loop (else NULL)
   void compute_loop_depth(int depth);
   void compute_freq(); // compute frequency with loop assuming head freq 1.0f
   void scale_freq();   // scale frequency by loop trip count (including outer loops)
   float outer_loop_freq() const; // frequency of outer loop
   bool in_loop_nest(Block* b);
   float trip_count() const { return 1.0f / _exit_prob; }
   virtual bool is_loop()  { return true; }
   int id() { return _id; }
 #ifndef PRODUCT
   void dump( ) const;
   void dump_tree() const;
 #endif
 };
 //----------------------------------CFGEdge------------------------------------
 // A edge between two basic blocks that will be embodied by a branch or a
 // fall-through.
 class CFGEdge : public ResourceObj {
   friend class VMStructs;
  private:
   Block * _from;        // Source basic block
   Block * _to;          // Destination basic block
   float _freq;          // Execution frequency (estimate)
   int   _state;
   bool  _infrequent;
   int   _from_pct;
   int   _to_pct;
   // Private accessors
   int  from_pct() const { return _from_pct; }
   int  to_pct()   const { return _to_pct;   }
   int  from_infrequent() const { return from_pct() < BlockLayoutMinDiamondPercentage; }
   int  to_infrequent()   const { return to_pct()   < BlockLayoutMinDiamondPercentage; }
  public:
   enum {
     open,               // initial edge state; unprocessed
     connected,          // edge used to connect two traces together
     interior            // edge is interior to trace (could be backedge)
   };
   CFGEdge(Block *from, Block *to, float freq, int from_pct, int to_pct) :
     _from(from), _to(to), _freq(freq),
     _from_pct(from_pct), _to_pct(to_pct), _state(open) {
     _infrequent = from_infrequent() || to_infrequent();
   }
   float  freq() const { return _freq; }
   Block* from() const { return _from; }
   Block* to  () const { return _to;   }
   int  infrequent() const { return _infrequent; }
   int state() const { return _state; }
   void set_state(int state) { _state = state; }
 #ifndef PRODUCT
   void dump( ) const;
 #endif
 };
 //-----------------------------------Trace-------------------------------------
 // An ordered list of basic blocks.
 class Trace : public ResourceObj {
  private:
   uint _id;             // Unique Trace id (derived from initial block)
   Block ** _next_list;  // Array mapping index to next block
   Block ** _prev_list;  // Array mapping index to previous block
   Block * _first;       // First block in the trace
   Block * _last;        // Last block in the trace
   // Return the block that follows "b" in the trace.
   Block * next(Block *b) const { return _next_list[b->_pre_order]; }
   void set_next(Block *b, Block *n) const { _next_list[b->_pre_order] = n; }
   // Return the block that precedes "b" in the trace.
   Block * prev(Block *b) const { return _prev_list[b->_pre_order]; }
   void set_prev(Block *b, Block *p) const { _prev_list[b->_pre_order] = p; }
   // We've discovered a loop in this trace. Reset last to be "b", and first as
   // the block following "b
   void break_loop_after(Block *b) {
     _last = b;
     _first = next(b);
     set_prev(_first, NULL);
     set_next(_last, NULL);
   }
  public:
   Trace(Block *b, Block **next_list, Block **prev_list) :
     _first(b),
     _last(b),
     _next_list(next_list),
     _prev_list(prev_list),
     _id(b->_pre_order) {
     set_next(b, NULL);
     set_prev(b, NULL);
   };
   // Return the id number
   uint id() const { return _id; }
   void set_id(uint id) { _id = id; }
   // Return the first block in the trace
   Block * first_block() const { return _first; }
   // Return the last block in the trace
   Block * last_block() const { return _last; }
   // Insert a trace in the middle of this one after b
   void insert_after(Block *b, Trace *tr) {
     set_next(tr->last_block(), next(b));
     if (next(b) != NULL) {
       set_prev(next(b), tr->last_block());
     }
     set_next(b, tr->first_block());
     set_prev(tr->first_block(), b);
     if (b == _last) {
       _last = tr->last_block();
     }
   }
   void insert_before(Block *b, Trace *tr) {
     Block *p = prev(b);
     assert(p != NULL, "use append instead");
     insert_after(p, tr);
   }
   // Append another trace to this one.
   void append(Trace *tr) {
     insert_after(_last, tr);
   }
   // Append a block at the end of this trace
   void append(Block *b) {
     set_next(_last, b);
     set_prev(b, _last);
     _last = b;
   }
   // Adjust the the blocks in this trace
   void fixup_blocks(PhaseCFG &cfg);
   bool backedge(CFGEdge *e);
 #ifndef PRODUCT
   void dump( ) const;
 #endif
 };
 //------------------------------PhaseBlockLayout-------------------------------
 // Rearrange blocks into some canonical order, based on edges and their frequencies
 class PhaseBlockLayout : public Phase {
   friend class VMStructs;
   PhaseCFG &_cfg;               // Control flow graph
   GrowableArray<CFGEdge *> *edges;
   Trace **traces;
   Block **next;
   Block **prev;
   UnionFind *uf;
   // Given a block, find its encompassing Trace
   Trace * trace(Block *b) {
     return traces[uf->Find_compress(b->_pre_order)];
   }
  public:
   PhaseBlockLayout(PhaseCFG &cfg);
   void find_edges();
   void grow_traces();
   void merge_traces(bool loose_connections);
   void reorder_traces(int count);
   void union_traces(Trace* from, Trace* to);
 };
 #endif // SHARE_VM_OPTO_BLOCK_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/opto/block.hpp@f90c822e73f8 (annotated)

src/share/vm/opto/block.hpp