changeset 1498 | 346bf226078e |
parent 1217 | 5eb97f366a6a |
child 2030 | 39d55e4534b4 |
1497:cd3234c89e59 | 1498:346bf226078e |
---|---|
55 push(b); // grow list by one block |
55 push(b); // grow list by one block |
56 Copy::conjoint_words_to_higher((HeapWord*)&_blocks[i], (HeapWord*)&_blocks[i+1], ((_cnt-i-1)*sizeof(Block*))); |
56 Copy::conjoint_words_to_higher((HeapWord*)&_blocks[i], (HeapWord*)&_blocks[i+1], ((_cnt-i-1)*sizeof(Block*))); |
57 _blocks[i] = b; |
57 _blocks[i] = b; |
58 } |
58 } |
59 |
59 |
60 #ifndef PRODUCT |
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61 void Block_List::print() { |
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62 for (uint i=0; i < size(); i++) { |
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63 tty->print("B%d ", _blocks[i]->_pre_order); |
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64 } |
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65 tty->print("size = %d\n", size()); |
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66 } |
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67 #endif |
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60 |
68 |
61 //============================================================================= |
69 //============================================================================= |
62 |
70 |
63 uint Block::code_alignment() { |
71 uint Block::code_alignment() { |
64 // Check for Root block |
72 // Check for Root block |
65 if( _pre_order == 0 ) return CodeEntryAlignment; |
73 if( _pre_order == 0 ) return CodeEntryAlignment; |
66 // Check for Start block |
74 // Check for Start block |
67 if( _pre_order == 1 ) return InteriorEntryAlignment; |
75 if( _pre_order == 1 ) return InteriorEntryAlignment; |
68 // Check for loop alignment |
76 // Check for loop alignment |
77 if (has_loop_alignment()) return loop_alignment(); |
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78 |
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79 return 1; // no particular alignment |
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80 } |
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81 |
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82 uint Block::compute_loop_alignment() { |
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69 Node *h = head(); |
83 Node *h = head(); |
70 if( h->is_Loop() && h->as_Loop()->is_inner_loop() ) { |
84 if( h->is_Loop() && h->as_Loop()->is_inner_loop() ) { |
71 // Pre- and post-loops have low trip count so do not bother with |
85 // Pre- and post-loops have low trip count so do not bother with |
72 // NOPs for align loop head. The constants are hidden from tuning |
86 // NOPs for align loop head. The constants are hidden from tuning |
73 // but only because my "divide by 4" heuristic surely gets nearly |
87 // but only because my "divide by 4" heuristic surely gets nearly |
81 if( n->is_MachIf() && n->as_MachIf()->_prob < 0.01 ) { |
95 if( n->is_MachIf() && n->as_MachIf()->_prob < 0.01 ) { |
82 return 1; // Loop does not loop, more often than not! |
96 return 1; // Loop does not loop, more often than not! |
83 } |
97 } |
84 return OptoLoopAlignment; // Otherwise align loop head |
98 return OptoLoopAlignment; // Otherwise align loop head |
85 } |
99 } |
100 |
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86 return 1; // no particular alignment |
101 return 1; // no particular alignment |
87 } |
102 } |
88 |
103 |
89 //----------------------------------------------------------------------------- |
104 //----------------------------------------------------------------------------- |
90 // Compute the size of first 'inst_cnt' instructions in this block. |
105 // Compute the size of first 'inst_cnt' instructions in this block. |
91 // Return the number of instructions left to compute if the block has |
106 // Return the number of instructions left to compute if the block has |
92 // less then 'inst_cnt' instructions. |
107 // less then 'inst_cnt' instructions. Stop, and return 0 if sum_size |
108 // exceeds OptoLoopAlignment. |
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93 uint Block::compute_first_inst_size(uint& sum_size, uint inst_cnt, |
109 uint Block::compute_first_inst_size(uint& sum_size, uint inst_cnt, |
94 PhaseRegAlloc* ra) { |
110 PhaseRegAlloc* ra) { |
95 uint last_inst = _nodes.size(); |
111 uint last_inst = _nodes.size(); |
96 for( uint j = 0; j < last_inst && inst_cnt > 0; j++ ) { |
112 for( uint j = 0; j < last_inst && inst_cnt > 0; j++ ) { |
97 uint inst_size = _nodes[j]->size(ra); |
113 uint inst_size = _nodes[j]->size(ra); |
305 bx = (*bbs)[bx->pred(1)->_idx]; |
321 bx = (*bbs)[bx->pred(1)->_idx]; |
306 } |
322 } |
307 tty->print("\tLoop: B%d-B%d ", bhead->_pre_order, bx->_pre_order); |
323 tty->print("\tLoop: B%d-B%d ", bhead->_pre_order, bx->_pre_order); |
308 // Dump any loop-specific bits, especially for CountedLoops. |
324 // Dump any loop-specific bits, especially for CountedLoops. |
309 loop->dump_spec(tty); |
325 loop->dump_spec(tty); |
326 } else if (has_loop_alignment()) { |
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327 tty->print(" top-of-loop"); |
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310 } |
328 } |
311 tty->print(" Freq: %g",_freq); |
329 tty->print(" Freq: %g",_freq); |
312 if( Verbose || WizardMode ) { |
330 if( Verbose || WizardMode ) { |
313 tty->print(" IDom: %d/#%d", _idom ? _idom->_pre_order : 0, _dom_depth); |
331 tty->print(" IDom: %d/#%d", _idom ? _idom->_pre_order : 0, _dom_depth); |
314 tty->print(" RegPressure: %d",_reg_pressure); |
332 tty->print(" RegPressure: %d",_reg_pressure); |
507 // flipped for another case? |
525 // flipped for another case? |
508 static bool no_flip_branch( Block *b ) { |
526 static bool no_flip_branch( Block *b ) { |
509 int branch_idx = b->_nodes.size() - b->_num_succs-1; |
527 int branch_idx = b->_nodes.size() - b->_num_succs-1; |
510 if( branch_idx < 1 ) return false; |
528 if( branch_idx < 1 ) return false; |
511 Node *bra = b->_nodes[branch_idx]; |
529 Node *bra = b->_nodes[branch_idx]; |
512 if( bra->is_Catch() ) return true; |
530 if( bra->is_Catch() ) |
531 return true; |
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513 if( bra->is_Mach() ) { |
532 if( bra->is_Mach() ) { |
514 if( bra->is_MachNullCheck() ) return true; |
533 if( bra->is_MachNullCheck() ) |
534 return true; |
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515 int iop = bra->as_Mach()->ideal_Opcode(); |
535 int iop = bra->as_Mach()->ideal_Opcode(); |
516 if( iop == Op_FastLock || iop == Op_FastUnlock ) |
536 if( iop == Op_FastLock || iop == Op_FastUnlock ) |
517 return true; |
537 return true; |
518 } |
538 } |
519 return false; |
539 return false; |
555 dead->head()->del_req(j); |
575 dead->head()->del_req(j); |
556 for( int k = 1; dead->_nodes[k]->is_Phi(); k++ ) |
576 for( int k = 1; dead->_nodes[k]->is_Phi(); k++ ) |
557 dead->_nodes[k]->del_req(j); |
577 dead->_nodes[k]->del_req(j); |
558 } |
578 } |
559 |
579 |
560 //------------------------------MoveToNext------------------------------------- |
580 //------------------------------move_to_next----------------------------------- |
561 // Helper function to move block bx to the slot following b_index. Return |
581 // Helper function to move block bx to the slot following b_index. Return |
562 // true if the move is successful, otherwise false |
582 // true if the move is successful, otherwise false |
563 bool PhaseCFG::MoveToNext(Block* bx, uint b_index) { |
583 bool PhaseCFG::move_to_next(Block* bx, uint b_index) { |
564 if (bx == NULL) return false; |
584 if (bx == NULL) return false; |
565 |
585 |
566 // Return false if bx is already scheduled. |
586 // Return false if bx is already scheduled. |
567 uint bx_index = bx->_pre_order; |
587 uint bx_index = bx->_pre_order; |
568 if ((bx_index <= b_index) && (_blocks[bx_index] == bx)) { |
588 if ((bx_index <= b_index) && (_blocks[bx_index] == bx)) { |
589 _blocks.remove(bx_index); |
609 _blocks.remove(bx_index); |
590 _blocks.insert(b_index + 1, bx); |
610 _blocks.insert(b_index + 1, bx); |
591 return true; |
611 return true; |
592 } |
612 } |
593 |
613 |
594 //------------------------------MoveToEnd-------------------------------------- |
614 //------------------------------move_to_end------------------------------------ |
595 // Move empty and uncommon blocks to the end. |
615 // Move empty and uncommon blocks to the end. |
596 void PhaseCFG::MoveToEnd(Block *b, uint i) { |
616 void PhaseCFG::move_to_end(Block *b, uint i) { |
597 int e = b->is_Empty(); |
617 int e = b->is_Empty(); |
598 if (e != Block::not_empty) { |
618 if (e != Block::not_empty) { |
599 if (e == Block::empty_with_goto) { |
619 if (e == Block::empty_with_goto) { |
600 // Remove the goto, but leave the block. |
620 // Remove the goto, but leave the block. |
601 b->_nodes.pop(); |
621 b->_nodes.pop(); |
607 // Move the empty block to the end, and don't recheck. |
627 // Move the empty block to the end, and don't recheck. |
608 _blocks.remove(i); |
628 _blocks.remove(i); |
609 _blocks.push(b); |
629 _blocks.push(b); |
610 } |
630 } |
611 |
631 |
612 //------------------------------RemoveEmpty------------------------------------ |
632 //---------------------------set_loop_alignment-------------------------------- |
613 // Remove empty basic blocks and useless branches. |
633 // Set loop alignment for every block |
614 void PhaseCFG::RemoveEmpty() { |
634 void PhaseCFG::set_loop_alignment() { |
635 uint last = _num_blocks; |
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636 assert( _blocks[0] == _broot, "" ); |
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637 |
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638 for (uint i = 1; i < last; i++ ) { |
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639 Block *b = _blocks[i]; |
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640 if (b->head()->is_Loop()) { |
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641 b->set_loop_alignment(b); |
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642 } |
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643 } |
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644 } |
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645 |
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646 //-----------------------------remove_empty------------------------------------ |
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647 // Make empty basic blocks to be "connector" blocks, Move uncommon blocks |
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648 // to the end. |
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649 void PhaseCFG::remove_empty() { |
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615 // Move uncommon blocks to the end |
650 // Move uncommon blocks to the end |
616 uint last = _num_blocks; |
651 uint last = _num_blocks; |
617 uint i; |
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618 assert( _blocks[0] == _broot, "" ); |
652 assert( _blocks[0] == _broot, "" ); |
619 for( i = 1; i < last; i++ ) { |
653 |
654 for (uint i = 1; i < last; i++) { |
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620 Block *b = _blocks[i]; |
655 Block *b = _blocks[i]; |
656 if (b->is_connector()) break; |
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621 |
657 |
622 // Check for NeverBranch at block end. This needs to become a GOTO to the |
658 // Check for NeverBranch at block end. This needs to become a GOTO to the |
623 // true target. NeverBranch are treated as a conditional branch that |
659 // true target. NeverBranch are treated as a conditional branch that |
624 // always goes the same direction for most of the optimizer and are used |
660 // always goes the same direction for most of the optimizer and are used |
625 // to give a fake exit path to infinite loops. At this late stage they |
661 // to give a fake exit path to infinite loops. At this late stage they |
627 // indeed hang. |
663 // indeed hang. |
628 if( b->_nodes[b->end_idx()]->Opcode() == Op_NeverBranch ) |
664 if( b->_nodes[b->end_idx()]->Opcode() == Op_NeverBranch ) |
629 convert_NeverBranch_to_Goto(b); |
665 convert_NeverBranch_to_Goto(b); |
630 |
666 |
631 // Look for uncommon blocks and move to end. |
667 // Look for uncommon blocks and move to end. |
632 if( b->is_uncommon(_bbs) ) { |
668 if (!C->do_freq_based_layout()) { |
633 MoveToEnd(b, i); |
669 if( b->is_uncommon(_bbs) ) { |
634 last--; // No longer check for being uncommon! |
670 move_to_end(b, i); |
635 if( no_flip_branch(b) ) { // Fall-thru case must follow? |
671 last--; // No longer check for being uncommon! |
636 b = _blocks[i]; // Find the fall-thru block |
672 if( no_flip_branch(b) ) { // Fall-thru case must follow? |
637 MoveToEnd(b, i); |
673 b = _blocks[i]; // Find the fall-thru block |
638 last--; |
674 move_to_end(b, i); |
639 } |
675 last--; |
640 i--; // backup block counter post-increment |
676 } |
641 } |
677 i--; // backup block counter post-increment |
642 } |
678 } |
643 |
679 } |
644 // Remove empty blocks |
680 } |
645 uint j1; |
681 |
682 // Move empty blocks to the end |
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646 last = _num_blocks; |
683 last = _num_blocks; |
647 for( i=0; i < last; i++ ) { |
684 for (uint i = 1; i < last; i++) { |
648 Block *b = _blocks[i]; |
685 Block *b = _blocks[i]; |
649 if (i > 0) { |
686 if (b->is_Empty() != Block::not_empty) { |
650 if (b->is_Empty() != Block::not_empty) { |
687 move_to_end(b, i); |
651 MoveToEnd(b, i); |
688 last--; |
652 last--; |
689 i--; |
653 i--; |
|
654 } |
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655 } |
690 } |
656 } // End of for all blocks |
691 } // End of for all blocks |
657 |
692 } |
693 |
|
694 //-----------------------------fixup_flow-------------------------------------- |
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695 // Fix up the final control flow for basic blocks. |
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696 void PhaseCFG::fixup_flow() { |
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658 // Fixup final control flow for the blocks. Remove jump-to-next |
697 // Fixup final control flow for the blocks. Remove jump-to-next |
659 // block. If neither arm of a IF follows the conditional branch, we |
698 // block. If neither arm of a IF follows the conditional branch, we |
660 // have to add a second jump after the conditional. We place the |
699 // have to add a second jump after the conditional. We place the |
661 // TRUE branch target in succs[0] for both GOTOs and IFs. |
700 // TRUE branch target in succs[0] for both GOTOs and IFs. |
662 for( i=0; i < _num_blocks; i++ ) { |
701 for (uint i=0; i < _num_blocks; i++) { |
663 Block *b = _blocks[i]; |
702 Block *b = _blocks[i]; |
664 b->_pre_order = i; // turn pre-order into block-index |
703 b->_pre_order = i; // turn pre-order into block-index |
665 |
704 |
666 // Connector blocks need no further processing. |
705 // Connector blocks need no further processing. |
667 if (b->is_connector()) { |
706 if (b->is_connector()) { |
698 } |
737 } |
699 break; |
738 break; |
700 } |
739 } |
701 } |
740 } |
702 // Remove all CatchProjs |
741 // Remove all CatchProjs |
703 for (j1 = 0; j1 < b->_num_succs; j1++) b->_nodes.pop(); |
742 for (uint j1 = 0; j1 < b->_num_succs; j1++) b->_nodes.pop(); |
704 |
743 |
705 } else if (b->_num_succs == 1) { |
744 } else if (b->_num_succs == 1) { |
706 // Block ends in a Goto? |
745 // Block ends in a Goto? |
707 if (bnext == bs0) { |
746 if (bnext == bs0) { |
708 // We fall into next block; remove the Goto |
747 // We fall into next block; remove the Goto |
728 // Check for neither successor block following the current |
767 // Check for neither successor block following the current |
729 // block ending in a conditional. If so, move one of the |
768 // block ending in a conditional. If so, move one of the |
730 // successors after the current one, provided that the |
769 // successors after the current one, provided that the |
731 // successor was previously unscheduled, but moveable |
770 // successor was previously unscheduled, but moveable |
732 // (i.e., all paths to it involve a branch). |
771 // (i.e., all paths to it involve a branch). |
733 if( bnext != bs0 && bnext != bs1 ) { |
772 if( !C->do_freq_based_layout() && bnext != bs0 && bnext != bs1 ) { |
734 |
|
735 // Choose the more common successor based on the probability |
773 // Choose the more common successor based on the probability |
736 // of the conditional branch. |
774 // of the conditional branch. |
737 Block *bx = bs0; |
775 Block *bx = bs0; |
738 Block *by = bs1; |
776 Block *by = bs1; |
739 |
777 |
749 bx = bs1; |
787 bx = bs1; |
750 by = bs0; |
788 by = bs0; |
751 } |
789 } |
752 |
790 |
753 // Attempt the more common successor first |
791 // Attempt the more common successor first |
754 if (MoveToNext(bx, i)) { |
792 if (move_to_next(bx, i)) { |
755 bnext = bx; |
793 bnext = bx; |
756 } else if (MoveToNext(by, i)) { |
794 } else if (move_to_next(by, i)) { |
757 bnext = by; |
795 bnext = by; |
758 } |
796 } |
759 } |
797 } |
760 |
798 |
761 // Check for conditional branching the wrong way. Negate |
799 // Check for conditional branching the wrong way. Negate |
772 b->_succs.map( 0, tbs1 ); |
810 b->_succs.map( 0, tbs1 ); |
773 b->_succs.map( 1, tbs0 ); |
811 b->_succs.map( 1, tbs0 ); |
774 // Flip projection for each target |
812 // Flip projection for each target |
775 { ProjNode *tmp = proj0; proj0 = proj1; proj1 = tmp; } |
813 { ProjNode *tmp = proj0; proj0 = proj1; proj1 = tmp; } |
776 |
814 |
777 } else if( bnext == bs1 ) { // Fall-thru is already in succs[1] |
815 } else if( bnext != bs1 ) { |
778 |
816 // Need a double-branch |
779 } else { // Else need a double-branch |
|
780 |
|
781 // The existing conditional branch need not change. |
817 // The existing conditional branch need not change. |
782 // Add a unconditional branch to the false target. |
818 // Add a unconditional branch to the false target. |
783 // Alas, it must appear in its own block and adding a |
819 // Alas, it must appear in its own block and adding a |
784 // block this late in the game is complicated. Sigh. |
820 // block this late in the game is complicated. Sigh. |
785 insert_goto_at(i, 1); |
821 insert_goto_at(i, 1); |
786 } |
822 } |
787 |
823 |
788 // Make sure we TRUE branch to the target |
824 // Make sure we TRUE branch to the target |
789 if( proj0->Opcode() == Op_IfFalse ) |
825 if( proj0->Opcode() == Op_IfFalse ) { |
790 iff->negate(); |
826 iff->negate(); |
827 } |
|
791 |
828 |
792 b->_nodes.pop(); // Remove IfFalse & IfTrue projections |
829 b->_nodes.pop(); // Remove IfFalse & IfTrue projections |
793 b->_nodes.pop(); |
830 b->_nodes.pop(); |
794 |
831 |
795 } else { |
832 } else { |
796 // Multi-exit block, e.g. a switch statement |
833 // Multi-exit block, e.g. a switch statement |
797 // But we don't need to do anything here |
834 // But we don't need to do anything here |
798 } |
835 } |
799 |
|
800 } // End of for all blocks |
836 } // End of for all blocks |
801 |
|
802 } |
837 } |
803 |
838 |
804 |
839 |
805 //------------------------------dump------------------------------------------- |
840 //------------------------------dump------------------------------------------- |
806 #ifndef PRODUCT |
841 #ifndef PRODUCT |
903 void UnionFind::reset( uint max ) { |
938 void UnionFind::reset( uint max ) { |
904 assert( max <= max_uint, "Must fit within uint" ); |
939 assert( max <= max_uint, "Must fit within uint" ); |
905 // Force the Union-Find mapping to be at least this large |
940 // Force the Union-Find mapping to be at least this large |
906 extend(max,0); |
941 extend(max,0); |
907 // Initialize to be the ID mapping. |
942 // Initialize to be the ID mapping. |
908 for( uint i=0; i<_max; i++ ) map(i,i); |
943 for( uint i=0; i<max; i++ ) map(i,i); |
909 } |
944 } |
910 |
945 |
911 //------------------------------Find_compress---------------------------------- |
946 //------------------------------Find_compress---------------------------------- |
912 // Straight out of Tarjan's union-find algorithm |
947 // Straight out of Tarjan's union-find algorithm |
913 uint UnionFind::Find_compress( uint idx ) { |
948 uint UnionFind::Find_compress( uint idx ) { |
935 // Off the end? This can happen during debugging dumps |
970 // Off the end? This can happen during debugging dumps |
936 // when data structures have not finished being updated. |
971 // when data structures have not finished being updated. |
937 if( idx >= _max ) return idx; |
972 if( idx >= _max ) return idx; |
938 uint next = lookup(idx); |
973 uint next = lookup(idx); |
939 while( next != idx ) { // Scan chain of equivalences |
974 while( next != idx ) { // Scan chain of equivalences |
940 assert( next < idx, "always union smaller" ); |
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941 idx = next; // until find a fixed-point |
975 idx = next; // until find a fixed-point |
942 next = lookup(idx); |
976 next = lookup(idx); |
943 } |
977 } |
944 return next; |
978 return next; |
945 } |
979 } |
954 assert( src < _max, "oob" ); |
988 assert( src < _max, "oob" ); |
955 assert( dst < _max, "oob" ); |
989 assert( dst < _max, "oob" ); |
956 assert( src < dst, "always union smaller" ); |
990 assert( src < dst, "always union smaller" ); |
957 map(dst,src); |
991 map(dst,src); |
958 } |
992 } |
993 |
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994 #ifndef PRODUCT |
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995 static void edge_dump(GrowableArray<CFGEdge *> *edges) { |
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996 tty->print_cr("---- Edges ----"); |
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997 for (int i = 0; i < edges->length(); i++) { |
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998 CFGEdge *e = edges->at(i); |
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999 if (e != NULL) { |
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1000 edges->at(i)->dump(); |
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1001 } |
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1002 } |
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1003 } |
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1004 |
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1005 static void trace_dump(Trace *traces[], int count) { |
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1006 tty->print_cr("---- Traces ----"); |
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1007 for (int i = 0; i < count; i++) { |
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1008 Trace *tr = traces[i]; |
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1009 if (tr != NULL) { |
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1010 tr->dump(); |
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1011 } |
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1012 } |
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1013 } |
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1014 |
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1015 void Trace::dump( ) const { |
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1016 tty->print_cr("Trace (freq %f)", first_block()->_freq); |
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1017 for (Block *b = first_block(); b != NULL; b = next(b)) { |
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1018 tty->print(" B%d", b->_pre_order); |
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1019 if (b->head()->is_Loop()) { |
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1020 tty->print(" (L%d)", b->compute_loop_alignment()); |
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1021 } |
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1022 if (b->has_loop_alignment()) { |
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1023 tty->print(" (T%d)", b->code_alignment()); |
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1024 } |
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1025 } |
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1026 tty->cr(); |
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1027 } |
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1028 |
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1029 void CFGEdge::dump( ) const { |
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1030 tty->print(" B%d --> B%d Freq: %f out:%3d%% in:%3d%% State: ", |
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1031 from()->_pre_order, to()->_pre_order, freq(), _from_pct, _to_pct); |
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1032 switch(state()) { |
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1033 case connected: |
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1034 tty->print("connected"); |
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1035 break; |
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1036 case open: |
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1037 tty->print("open"); |
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1038 break; |
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1039 case interior: |
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1040 tty->print("interior"); |
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1041 break; |
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1042 } |
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1043 if (infrequent()) { |
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1044 tty->print(" infrequent"); |
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1045 } |
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1046 tty->cr(); |
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1047 } |
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1048 #endif |
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1049 |
|
1050 //============================================================================= |
|
1051 |
|
1052 //------------------------------edge_order------------------------------------- |
|
1053 // Comparison function for edges |
|
1054 static int edge_order(CFGEdge **e0, CFGEdge **e1) { |
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1055 float freq0 = (*e0)->freq(); |
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1056 float freq1 = (*e1)->freq(); |
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1057 if (freq0 != freq1) { |
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1058 return freq0 > freq1 ? -1 : 1; |
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1059 } |
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1060 |
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1061 int dist0 = (*e0)->to()->_rpo - (*e0)->from()->_rpo; |
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1062 int dist1 = (*e1)->to()->_rpo - (*e1)->from()->_rpo; |
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1063 |
|
1064 return dist1 - dist0; |
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1065 } |
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1066 |
|
1067 //------------------------------trace_frequency_order-------------------------- |
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1068 // Comparison function for edges |
|
1069 static int trace_frequency_order(const void *p0, const void *p1) { |
|
1070 Trace *tr0 = *(Trace **) p0; |
|
1071 Trace *tr1 = *(Trace **) p1; |
|
1072 Block *b0 = tr0->first_block(); |
|
1073 Block *b1 = tr1->first_block(); |
|
1074 |
|
1075 // The trace of connector blocks goes at the end; |
|
1076 // we only expect one such trace |
|
1077 if (b0->is_connector() != b1->is_connector()) { |
|
1078 return b1->is_connector() ? -1 : 1; |
|
1079 } |
|
1080 |
|
1081 // Pull more frequently executed blocks to the beginning |
|
1082 float freq0 = b0->_freq; |
|
1083 float freq1 = b1->_freq; |
|
1084 if (freq0 != freq1) { |
|
1085 return freq0 > freq1 ? -1 : 1; |
|
1086 } |
|
1087 |
|
1088 int diff = tr0->first_block()->_rpo - tr1->first_block()->_rpo; |
|
1089 |
|
1090 return diff; |
|
1091 } |
|
1092 |
|
1093 //------------------------------find_edges------------------------------------- |
|
1094 // Find edges of interest, i.e, those which can fall through. Presumes that |
|
1095 // edges which don't fall through are of low frequency and can be generally |
|
1096 // ignored. Initialize the list of traces. |
|
1097 void PhaseBlockLayout::find_edges() |
|
1098 { |
|
1099 // Walk the blocks, creating edges and Traces |
|
1100 uint i; |
|
1101 Trace *tr = NULL; |
|
1102 for (i = 0; i < _cfg._num_blocks; i++) { |
|
1103 Block *b = _cfg._blocks[i]; |
|
1104 tr = new Trace(b, next, prev); |
|
1105 traces[tr->id()] = tr; |
|
1106 |
|
1107 // All connector blocks should be at the end of the list |
|
1108 if (b->is_connector()) break; |
|
1109 |
|
1110 // If this block and the next one have a one-to-one successor |
|
1111 // predecessor relationship, simply append the next block |
|
1112 int nfallthru = b->num_fall_throughs(); |
|
1113 while (nfallthru == 1 && |
|
1114 b->succ_fall_through(0)) { |
|
1115 Block *n = b->_succs[0]; |
|
1116 |
|
1117 // Skip over single-entry connector blocks, we don't want to |
|
1118 // add them to the trace. |
|
1119 while (n->is_connector() && n->num_preds() == 1) { |
|
1120 n = n->_succs[0]; |
|
1121 } |
|
1122 |
|
1123 // We see a merge point, so stop search for the next block |
|
1124 if (n->num_preds() != 1) break; |
|
1125 |
|
1126 i++; |
|
1127 assert(n = _cfg._blocks[i], "expecting next block"); |
|
1128 tr->append(n); |
|
1129 uf->map(n->_pre_order, tr->id()); |
|
1130 traces[n->_pre_order] = NULL; |
|
1131 nfallthru = b->num_fall_throughs(); |
|
1132 b = n; |
|
1133 } |
|
1134 |
|
1135 if (nfallthru > 0) { |
|
1136 // Create a CFGEdge for each outgoing |
|
1137 // edge that could be a fall-through. |
|
1138 for (uint j = 0; j < b->_num_succs; j++ ) { |
|
1139 if (b->succ_fall_through(j)) { |
|
1140 Block *target = b->non_connector_successor(j); |
|
1141 float freq = b->_freq * b->succ_prob(j); |
|
1142 int from_pct = (int) ((100 * freq) / b->_freq); |
|
1143 int to_pct = (int) ((100 * freq) / target->_freq); |
|
1144 edges->append(new CFGEdge(b, target, freq, from_pct, to_pct)); |
|
1145 } |
|
1146 } |
|
1147 } |
|
1148 } |
|
1149 |
|
1150 // Group connector blocks into one trace |
|
1151 for (i++; i < _cfg._num_blocks; i++) { |
|
1152 Block *b = _cfg._blocks[i]; |
|
1153 assert(b->is_connector(), "connector blocks at the end"); |
|
1154 tr->append(b); |
|
1155 uf->map(b->_pre_order, tr->id()); |
|
1156 traces[b->_pre_order] = NULL; |
|
1157 } |
|
1158 } |
|
1159 |
|
1160 //------------------------------union_traces---------------------------------- |
|
1161 // Union two traces together in uf, and null out the trace in the list |
|
1162 void PhaseBlockLayout::union_traces(Trace* updated_trace, Trace* old_trace) |
|
1163 { |
|
1164 uint old_id = old_trace->id(); |
|
1165 uint updated_id = updated_trace->id(); |
|
1166 |
|
1167 uint lo_id = updated_id; |
|
1168 uint hi_id = old_id; |
|
1169 |
|
1170 // If from is greater than to, swap values to meet |
|
1171 // UnionFind guarantee. |
|
1172 if (updated_id > old_id) { |
|
1173 lo_id = old_id; |
|
1174 hi_id = updated_id; |
|
1175 |
|
1176 // Fix up the trace ids |
|
1177 traces[lo_id] = traces[updated_id]; |
|
1178 updated_trace->set_id(lo_id); |
|
1179 } |
|
1180 |
|
1181 // Union the lower with the higher and remove the pointer |
|
1182 // to the higher. |
|
1183 uf->Union(lo_id, hi_id); |
|
1184 traces[hi_id] = NULL; |
|
1185 } |
|
1186 |
|
1187 //------------------------------grow_traces------------------------------------- |
|
1188 // Append traces together via the most frequently executed edges |
|
1189 void PhaseBlockLayout::grow_traces() |
|
1190 { |
|
1191 // Order the edges, and drive the growth of Traces via the most |
|
1192 // frequently executed edges. |
|
1193 edges->sort(edge_order); |
|
1194 for (int i = 0; i < edges->length(); i++) { |
|
1195 CFGEdge *e = edges->at(i); |
|
1196 |
|
1197 if (e->state() != CFGEdge::open) continue; |
|
1198 |
|
1199 Block *src_block = e->from(); |
|
1200 Block *targ_block = e->to(); |
|
1201 |
|
1202 // Don't grow traces along backedges? |
|
1203 if (!BlockLayoutRotateLoops) { |
|
1204 if (targ_block->_rpo <= src_block->_rpo) { |
|
1205 targ_block->set_loop_alignment(targ_block); |
|
1206 continue; |
|
1207 } |
|
1208 } |
|
1209 |
|
1210 Trace *src_trace = trace(src_block); |
|
1211 Trace *targ_trace = trace(targ_block); |
|
1212 |
|
1213 // If the edge in question can join two traces at their ends, |
|
1214 // append one trace to the other. |
|
1215 if (src_trace->last_block() == src_block) { |
|
1216 if (src_trace == targ_trace) { |
|
1217 e->set_state(CFGEdge::interior); |
|
1218 if (targ_trace->backedge(e)) { |
|
1219 // Reset i to catch any newly eligible edge |
|
1220 // (Or we could remember the first "open" edge, and reset there) |
|
1221 i = 0; |
|
1222 } |
|
1223 } else if (targ_trace->first_block() == targ_block) { |
|
1224 e->set_state(CFGEdge::connected); |
|
1225 src_trace->append(targ_trace); |
|
1226 union_traces(src_trace, targ_trace); |
|
1227 } |
|
1228 } |
|
1229 } |
|
1230 } |
|
1231 |
|
1232 //------------------------------merge_traces----------------------------------- |
|
1233 // Embed one trace into another, if the fork or join points are sufficiently |
|
1234 // balanced. |
|
1235 void PhaseBlockLayout::merge_traces(bool fall_thru_only) |
|
1236 { |
|
1237 // Walk the edge list a another time, looking at unprocessed edges. |
|
1238 // Fold in diamonds |
|
1239 for (int i = 0; i < edges->length(); i++) { |
|
1240 CFGEdge *e = edges->at(i); |
|
1241 |
|
1242 if (e->state() != CFGEdge::open) continue; |
|
1243 if (fall_thru_only) { |
|
1244 if (e->infrequent()) continue; |
|
1245 } |
|
1246 |
|
1247 Block *src_block = e->from(); |
|
1248 Trace *src_trace = trace(src_block); |
|
1249 bool src_at_tail = src_trace->last_block() == src_block; |
|
1250 |
|
1251 Block *targ_block = e->to(); |
|
1252 Trace *targ_trace = trace(targ_block); |
|
1253 bool targ_at_start = targ_trace->first_block() == targ_block; |
|
1254 |
|
1255 if (src_trace == targ_trace) { |
|
1256 // This may be a loop, but we can't do much about it. |
|
1257 e->set_state(CFGEdge::interior); |
|
1258 continue; |
|
1259 } |
|
1260 |
|
1261 if (fall_thru_only) { |
|
1262 // If the edge links the middle of two traces, we can't do anything. |
|
1263 // Mark the edge and continue. |
|
1264 if (!src_at_tail & !targ_at_start) { |
|
1265 continue; |
|
1266 } |
|
1267 |
|
1268 // Don't grow traces along backedges? |
|
1269 if (!BlockLayoutRotateLoops && (targ_block->_rpo <= src_block->_rpo)) { |
|
1270 continue; |
|
1271 } |
|
1272 |
|
1273 // If both ends of the edge are available, why didn't we handle it earlier? |
|
1274 assert(src_at_tail ^ targ_at_start, "Should have caught this edge earlier."); |
|
1275 |
|
1276 if (targ_at_start) { |
|
1277 // Insert the "targ" trace in the "src" trace if the insertion point |
|
1278 // is a two way branch. |
|
1279 // Better profitability check possible, but may not be worth it. |
|
1280 // Someday, see if the this "fork" has an associated "join"; |
|
1281 // then make a policy on merging this trace at the fork or join. |
|
1282 // For example, other things being equal, it may be better to place this |
|
1283 // trace at the join point if the "src" trace ends in a two-way, but |
|
1284 // the insertion point is one-way. |
|
1285 assert(src_block->num_fall_throughs() == 2, "unexpected diamond"); |
|
1286 e->set_state(CFGEdge::connected); |
|
1287 src_trace->insert_after(src_block, targ_trace); |
|
1288 union_traces(src_trace, targ_trace); |
|
1289 } else if (src_at_tail) { |
|
1290 if (src_trace != trace(_cfg._broot)) { |
|
1291 e->set_state(CFGEdge::connected); |
|
1292 targ_trace->insert_before(targ_block, src_trace); |
|
1293 union_traces(targ_trace, src_trace); |
|
1294 } |
|
1295 } |
|
1296 } else if (e->state() == CFGEdge::open) { |
|
1297 // Append traces, even without a fall-thru connection. |
|
1298 // But leave root entry at the begining of the block list. |
|
1299 if (targ_trace != trace(_cfg._broot)) { |
|
1300 e->set_state(CFGEdge::connected); |
|
1301 src_trace->append(targ_trace); |
|
1302 union_traces(src_trace, targ_trace); |
|
1303 } |
|
1304 } |
|
1305 } |
|
1306 } |
|
1307 |
|
1308 //----------------------------reorder_traces----------------------------------- |
|
1309 // Order the sequence of the traces in some desirable way, and fixup the |
|
1310 // jumps at the end of each block. |
|
1311 void PhaseBlockLayout::reorder_traces(int count) |
|
1312 { |
|
1313 ResourceArea *area = Thread::current()->resource_area(); |
|
1314 Trace ** new_traces = NEW_ARENA_ARRAY(area, Trace *, count); |
|
1315 Block_List worklist; |
|
1316 int new_count = 0; |
|
1317 |
|
1318 // Compact the traces. |
|
1319 for (int i = 0; i < count; i++) { |
|
1320 Trace *tr = traces[i]; |
|
1321 if (tr != NULL) { |
|
1322 new_traces[new_count++] = tr; |
|
1323 } |
|
1324 } |
|
1325 |
|
1326 // The entry block should be first on the new trace list. |
|
1327 Trace *tr = trace(_cfg._broot); |
|
1328 assert(tr == new_traces[0], "entry trace misplaced"); |
|
1329 |
|
1330 // Sort the new trace list by frequency |
|
1331 qsort(new_traces + 1, new_count - 1, sizeof(new_traces[0]), trace_frequency_order); |
|
1332 |
|
1333 // Patch up the successor blocks |
|
1334 _cfg._blocks.reset(); |
|
1335 _cfg._num_blocks = 0; |
|
1336 for (int i = 0; i < new_count; i++) { |
|
1337 Trace *tr = new_traces[i]; |
|
1338 if (tr != NULL) { |
|
1339 tr->fixup_blocks(_cfg); |
|
1340 } |
|
1341 } |
|
1342 } |
|
1343 |
|
1344 //------------------------------PhaseBlockLayout------------------------------- |
|
1345 // Order basic blocks based on frequency |
|
1346 PhaseBlockLayout::PhaseBlockLayout(PhaseCFG &cfg) : |
|
1347 Phase(BlockLayout), |
|
1348 _cfg(cfg) |
|
1349 { |
|
1350 ResourceMark rm; |
|
1351 ResourceArea *area = Thread::current()->resource_area(); |
|
1352 |
|
1353 // List of traces |
|
1354 int size = _cfg._num_blocks + 1; |
|
1355 traces = NEW_ARENA_ARRAY(area, Trace *, size); |
|
1356 memset(traces, 0, size*sizeof(Trace*)); |
|
1357 next = NEW_ARENA_ARRAY(area, Block *, size); |
|
1358 memset(next, 0, size*sizeof(Block *)); |
|
1359 prev = NEW_ARENA_ARRAY(area, Block *, size); |
|
1360 memset(prev , 0, size*sizeof(Block *)); |
|
1361 |
|
1362 // List of edges |
|
1363 edges = new GrowableArray<CFGEdge*>; |
|
1364 |
|
1365 // Mapping block index --> block_trace |
|
1366 uf = new UnionFind(size); |
|
1367 uf->reset(size); |
|
1368 |
|
1369 // Find edges and create traces. |
|
1370 find_edges(); |
|
1371 |
|
1372 // Grow traces at their ends via most frequent edges. |
|
1373 grow_traces(); |
|
1374 |
|
1375 // Merge one trace into another, but only at fall-through points. |
|
1376 // This may make diamonds and other related shapes in a trace. |
|
1377 merge_traces(true); |
|
1378 |
|
1379 // Run merge again, allowing two traces to be catenated, even if |
|
1380 // one does not fall through into the other. This appends loosely |
|
1381 // related traces to be near each other. |
|
1382 merge_traces(false); |
|
1383 |
|
1384 // Re-order all the remaining traces by frequency |
|
1385 reorder_traces(size); |
|
1386 |
|
1387 assert(_cfg._num_blocks >= (uint) (size - 1), "number of blocks can not shrink"); |
|
1388 } |
|
1389 |
|
1390 |
|
1391 //------------------------------backedge--------------------------------------- |
|
1392 // Edge e completes a loop in a trace. If the target block is head of the |
|
1393 // loop, rotate the loop block so that the loop ends in a conditional branch. |
|
1394 bool Trace::backedge(CFGEdge *e) { |
|
1395 bool loop_rotated = false; |
|
1396 Block *src_block = e->from(); |
|
1397 Block *targ_block = e->to(); |
|
1398 |
|
1399 assert(last_block() == src_block, "loop discovery at back branch"); |
|
1400 if (first_block() == targ_block) { |
|
1401 if (BlockLayoutRotateLoops && last_block()->num_fall_throughs() < 2) { |
|
1402 // Find the last block in the trace that has a conditional |
|
1403 // branch. |
|
1404 Block *b; |
|
1405 for (b = last_block(); b != NULL; b = prev(b)) { |
|
1406 if (b->num_fall_throughs() == 2) { |
|
1407 break; |
|
1408 } |
|
1409 } |
|
1410 |
|
1411 if (b != last_block() && b != NULL) { |
|
1412 loop_rotated = true; |
|
1413 |
|
1414 // Rotate the loop by doing two-part linked-list surgery. |
|
1415 append(first_block()); |
|
1416 break_loop_after(b); |
|
1417 } |
|
1418 } |
|
1419 |
|
1420 // Backbranch to the top of a trace |
|
1421 // Scroll foward through the trace from the targ_block. If we find |
|
1422 // a loop head before another loop top, use the the loop head alignment. |
|
1423 for (Block *b = targ_block; b != NULL; b = next(b)) { |
|
1424 if (b->has_loop_alignment()) { |
|
1425 break; |
|
1426 } |
|
1427 if (b->head()->is_Loop()) { |
|
1428 targ_block = b; |
|
1429 break; |
|
1430 } |
|
1431 } |
|
1432 |
|
1433 first_block()->set_loop_alignment(targ_block); |
|
1434 |
|
1435 } else { |
|
1436 // Backbranch into the middle of a trace |
|
1437 targ_block->set_loop_alignment(targ_block); |
|
1438 } |
|
1439 |
|
1440 return loop_rotated; |
|
1441 } |
|
1442 |
|
1443 //------------------------------fixup_blocks----------------------------------- |
|
1444 // push blocks onto the CFG list |
|
1445 // ensure that blocks have the correct two-way branch sense |
|
1446 void Trace::fixup_blocks(PhaseCFG &cfg) { |
|
1447 Block *last = last_block(); |
|
1448 for (Block *b = first_block(); b != NULL; b = next(b)) { |
|
1449 cfg._blocks.push(b); |
|
1450 cfg._num_blocks++; |
|
1451 if (!b->is_connector()) { |
|
1452 int nfallthru = b->num_fall_throughs(); |
|
1453 if (b != last) { |
|
1454 if (nfallthru == 2) { |
|
1455 // Ensure that the sense of the branch is correct |
|
1456 Block *bnext = next(b); |
|
1457 Block *bs0 = b->non_connector_successor(0); |
|
1458 |
|
1459 MachNode *iff = b->_nodes[b->_nodes.size()-3]->as_Mach(); |
|
1460 ProjNode *proj0 = b->_nodes[b->_nodes.size()-2]->as_Proj(); |
|
1461 ProjNode *proj1 = b->_nodes[b->_nodes.size()-1]->as_Proj(); |
|
1462 |
|
1463 if (bnext == bs0) { |
|
1464 // Fall-thru case in succs[0], should be in succs[1] |
|
1465 |
|
1466 // Flip targets in _succs map |
|
1467 Block *tbs0 = b->_succs[0]; |
|
1468 Block *tbs1 = b->_succs[1]; |
|
1469 b->_succs.map( 0, tbs1 ); |
|
1470 b->_succs.map( 1, tbs0 ); |
|
1471 |
|
1472 // Flip projections to match targets |
|
1473 b->_nodes.map(b->_nodes.size()-2, proj1); |
|
1474 b->_nodes.map(b->_nodes.size()-1, proj0); |
|
1475 } |
|
1476 } |
|
1477 } |
|
1478 } |
|
1479 } |
|
1480 } |