| /* |
| * 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. |
| * |
| */ |
| |
| // 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 { |
| uint _size; // allocated size, as opposed to formal limit |
| debug_only(uint _limit;) // limit to formal domain |
| protected: |
| Block **_blocks; |
| void grow( uint i ); // Grow array node to fit |
| |
| public: |
| Arena *_arena; // Arena to allocate in |
| |
| 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 { |
| 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; } |
| }; |
| |
| |
| class CFGElement : public ResourceObj { |
| 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 { |
| public: |
| // Nodes in this block, in order |
| Node_List _nodes; |
| |
| // 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 _nodes[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 |
| |
| 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(); |
| |
| // 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( !head()->is_Loop() || |
| padding <= (uint)MaxLoopPad || |
| first_inst_size() > padding ) { |
| 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; }; |
| |
| // 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) { |
| _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 ) { _nodes.insert(end_idx(),n); } |
| // Find node in block |
| uint find_node( const Node *n ) const; |
| // Find and remove n from block list |
| void find_remove( const Node *n ); |
| |
| // Schedule a call next in the block |
| uint sched_call(Matcher &matcher, Block_Array &bbs, uint node_cnt, Node_List &worklist, int *ready_cnt, MachCallNode *mcall, VectorSet &next_call); |
| |
| // Perform basic-block local scheduling |
| Node *select(PhaseCFG *cfg, Node_List &worklist, int *ready_cnt, VectorSet &next_call, uint sched_slot); |
| void set_next_call( Node *n, VectorSet &next_call, Block_Array &bbs ); |
| void needed_for_next_call(Node *this_call, VectorSet &next_call, Block_Array &bbs); |
| bool schedule_local(PhaseCFG *cfg, Matcher &m, int *ready_cnt, VectorSet &next_call); |
| // Cleanup if any code lands between a Call and his Catch |
| void call_catch_cleanup(Block_Array &bbs); |
| // 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(PhaseCFG *cfg, Node *proj, Node *val, int allowed_reasons); |
| |
| // 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; |
| } |
| |
| // 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; |
| |
| // Use frequency calculations and code shape to predict if the block |
| // is uncommon. |
| bool is_uncommon( Block_Array &bbs ) const; |
| |
| #ifndef PRODUCT |
| // Debugging print of basic block |
| void dump_bidx(const Block* orig) const; |
| void dump_pred(const Block_Array *bbs, Block* orig) const; |
| void dump_head( const Block_Array *bbs ) const; |
| void dump( ) const; |
| void dump( const Block_Array *bbs ) const; |
| #endif |
| }; |
| |
| |
| //------------------------------PhaseCFG--------------------------------------- |
| // Build an array of Basic Block pointers, one per Node. |
| class PhaseCFG : public Phase { |
| private: |
| // Build a proper looking cfg. Return count of basic blocks |
| uint build_cfg(); |
| |
| // Perform DFS search. |
| // Setup 'vertex' as DFS to vertex mapping. |
| // Setup 'semi' as vertex to DFS mapping. |
| // Set 'parent' to DFS parent. |
| uint DFS( Tarjan *tarjan ); |
| |
| // Helper function to insert a node into a block |
| void schedule_node_into_block( Node *n, Block *b ); |
| |
| // 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. |
| MachNode *_goto; |
| void insert_goto_at(uint block_no, uint succ_no); |
| |
| Block* insert_anti_dependences(Block* LCA, Node* load, bool verify = false); |
| void verify_anti_dependences(Block* LCA, Node* load) { |
| assert(LCA == _bbs[load->_idx], "should already be scheduled"); |
| insert_anti_dependences(LCA, load, true); |
| } |
| |
| public: |
| PhaseCFG( Arena *a, RootNode *r, Matcher &m ); |
| |
| uint _num_blocks; // Count of basic blocks |
| Block_List _blocks; // List of basic blocks |
| RootNode *_root; // Root of whole program |
| Block_Array _bbs; // Map Nodes to owning Basic Block |
| Block *_broot; // Basic block of root |
| uint _rpo_ctr; |
| CFGLoop* _root_loop; |
| |
| // Per node latency estimation, valid only during GCM |
| GrowableArray<uint> _node_latency; |
| |
| #ifndef PRODUCT |
| bool _trace_opto_pipelining; // tracing flag |
| #endif |
| |
| // Build dominators |
| void Dominators(); |
| |
| // Estimate block frequencies based on IfNode probabilities |
| void Estimate_Block_Frequency(); |
| |
| // Global Code Motion. See Click's PLDI95 paper. Place Nodes in specific |
| // basic blocks; i.e. _bbs now maps _idx for all Nodes to some Block. |
| void GlobalCodeMotion( Matcher &m, uint unique, Node_List &proj_list ); |
| |
| // Compute the (backwards) latency of a node from the uses |
| void latency_from_uses(Node *n); |
| |
| // 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); |
| |
| // 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); |
| |
| // 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); |
| |
| // Compute the instruction global latency with a backwards walk |
| void ComputeLatenciesBackwards(VectorSet &visited, Node_List &stack); |
| |
| // Remove empty basic blocks |
| void RemoveEmpty(); |
| bool MoveToNext(Block* bx, uint b_index); |
| void MoveToEnd(Block* bx, uint b_index); |
| |
| // 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(); |
| |
| // Insert a node into a block, and update the _bbs |
| void insert( Block *b, uint idx, Node *n ) { |
| b->_nodes.insert( idx, n ); |
| _bbs.map( n->_idx, b ); |
| } |
| |
| #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 |
| }; |
| |
| |
| //------------------------------UnionFindInfo---------------------------------- |
| // 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 { |
| 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, Block_Array& node_to_blk); |
| 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) |
| 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 |
| }; |