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Overview
Comment: | Finish forward analysis in the jump threading pass. |
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Timelines: | family | ancestors | descendants | both | notworking | kbk-jumpthread |
Files: | files | file ages | folders |
SHA3-256: |
dc90afa15da03698d19ea19488876d2b |
User & Date: | kbk 2018-12-16 04:43:56.585 |
Context
2018-12-16
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04:55 | Add a 'cos2' test case to illustrate the cost of non-numeric ordering comparisons check-in: 86167d6917 user: kbk tags: notworking, kbk-jumpthread | |
04:43 | Finish forward analysis in the jump threading pass. check-in: dc90afa15d user: kbk tags: notworking, kbk-jumpthread | |
2018-12-10
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04:51 | Remove vestiges of the old node splitter from 'inline.tcl'. Make console dribble in 'jumpthread.tcl' contingent on debug-jumpthread. check-in: fd2ea3e6f1 user: kbk tags: notworking, kbk-jumpthread | |
Changes
Changes to quadcode/jumpthread.tcl.
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159 160 161 162 163 164 165 | # block. my jt_backward # Identify which subsets of the conditions are reachable on specific # control flow paths, so that blocks can be replicated to have known # entry conditions. Also report the (up to two) successors for each | | > > > > > > > > > > > > | 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 | # block. my jt_backward # Identify which subsets of the conditions are reachable on specific # control flow paths, so that blocks can be replicated to have known # entry conditions. Also report the (up to two) successors for each # variant block. my jt_forward my debug-jumpthread { my variable jt_variants puts "Variants found:" set b -1 foreach vs $jt_variants { incr b dict for {m ss} $vs { puts [format " %d (%llx): %s" $b $m $ss] } } } # TODO: Once all the variants have been listed, if any block has more than # one variant, deconstruct SSA. Replicate the blocks into variants, # redirecting their exits as needed (and tracking preds). Sort the # blocks. Reconstruct SSA, solve ud- and du-chains, propagate # copies, remove unreachable code, and recalculate bbidom/bblevel. # (May want to inspect the result to see whether another try at |
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239 240 241 242 243 244 245 | # Side effects: # # Constructs the list, jt_antin, indexed by basic block number, # containing dictionaries. The dictionaries describe the conditions # that will inform jump threading downstream of the entry to the basic # blocks. The dictionaries have two levels. The first level key gives # the name of a value in the quadcode, and the second gives a condition | | | > > > < < | 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 | # Side effects: # # Constructs the list, jt_antin, indexed by basic block number, # containing dictionaries. The dictionaries describe the conditions # that will inform jump threading downstream of the entry to the basic # blocks. The dictionaries have two levels. The first level key gives # the name of a value in the quadcode, and the second gives a condition # on that value's type. The second key is either 'is TYPECONST' # or 'isnot TYPECONST' for a given value in quadcode::dataTypes. # The values in the dictionary are ordinal numbers of conditions in the # block, and will be used to construct bit vectors of what conditions # are satisfied in a copy of the block. oo::define quadcode::transformer method jt_backward {} { namespace upvar ::quadcode jt_removable jt_removable my variable jt_antin set jt_antin [lrepeat [llength $bbcontent] {}] set changed 1 while {$changed} { set changed 0 my debug-jumpthread { |
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349 350 351 352 353 354 355 | } dict unset antin $dest } } } if {$antin ne [lindex $jt_antin $b]} { | < > | > > | | | > > | | 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 | } dict unset antin $dest } } } if {$antin ne [lindex $jt_antin $b]} { set changed 1 lset jt_antin $b $antin my debug-jumpthread { puts " bb $b: anticipable conditions:" } set cn -1 dict for {v conds} $antin { foreach c [dict keys $conds] { lassign $c what type my debug-jumpthread { puts " [incr cn]: $v $what $type\ ([nameOfType $type])" } } } } } } |
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402 403 404 405 406 407 408 | # in basic blocks prior to attempting to split them. # # Results: # None. # # Side effects: # | | | | > | < > > > > > > | | 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 | # in basic blocks prior to attempting to split them. # # Results: # None. # # Side effects: # # The ultimate output of this procedure is a list, 'jt_variants', # with one entry per basic block of the original sequence. The # elements of the list are dictionaries whose keys are bit vectors # that specify the set of anticipated conditions that are satisfied # in a desired copy of the block. The values are lists of up to two # bit vectors, that give the sets of anticipated conditions that # are satisfied in the block's successors. oo::define quadcode::transformer method jt_forward {} { # jt_stack is a list of alternating basic block number and # condition bit vector, used to track work that still needs to be # done. my variable jt_stack my variable jt_variants my debug-jumpthread { puts "Begin forward jump threading analysis for [my full-name]" } # Initially, the work list contains just the entry node, and # nothing is known on entry to it (there shouldn't # be any anticipated conditions there!) set jt_stack [list 0 0] set jt_variants [lrepeat [llength $bbcontent] {}] lset jt_variants 0 {0 {}} # Pop entries off the worklist and process them while {[llength $jt_stack] > 0} { set b [lindex $jt_stack end-1] set condMask [lindex $jt_stack end] set jt_stack [lreplace $jt_stack[set jt_stack ""] end-1 end] |
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457 458 459 460 461 462 463 | # For each successor to the block, propagates the promised # conditions forward into the successor. If the successor has # a set of conditions that has not yet been visited, adds it # to 'jt_variants' and stacks it for processing. oo::define quadcode::transformer method jt_forward_worker {b mask} { | | | < | < | | < < < < < | < < < < > | | < < | < < | > | < < > | < > > > > > > | > | > > > > > > > | > > > > > > > > > > > > > > > > > > > > > > | > > | > > > > > > | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | > > > > > | > > > > > | > > > > > | > | > > > > > > | > | > > > > > | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | > > > > > | > | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | > > > | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | > > > | > > > | > > > > > > > > > > > > | > > > > > > > > > > | > | | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | > > > > > | | | | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 | # For each successor to the block, propagates the promised # conditions forward into the successor. If the successor has # a set of conditions that has not yet been visited, adds it # to 'jt_variants' and stacks it for processing. oo::define quadcode::transformer method jt_forward_worker {b mask} { namespace upvar ::quadcode::dataType ARRAY ARRAY CONST0 CONST0 \ CONST1 CONST1 IMPURE IMPURE NEXIST NEXIST my debug-jumpthread { puts " bb $b:" } # Find out what assertions are guaranteed by $mask set asserted [my jt_maskToAssertions $b $mask] # Narrow the types of variables flowing into the block, according # to the assertions. set localtypes [my jt_applyAllAssertions $asserted] # Analyze the instructions of the block in the forward direction. # If an instruction is one that participates in jump threading, update # the assertions that apply to the block accordingly. If the instruction # is a threaded jump, set up to process the block's successor(s). set bb [lindex $bbcontent $b] set pc -1 foreach q $bb { incr pc my debug-jumpthread { puts " $pc: $q" } lassign $q opcode result operand1 lassign $opcode op totype typename set fromtype [my jt_localtype $operand1 $localtypes] switch -exact -- $op { "arrayExists" { if {[quadcode::dataType::isa $fromtype $ARRAY]} { dict set localtypes $result $CONST1 } elseif {![quadcode::dataType::mightbea $fromtype $ARRAY]} { dict set localtypes $result $CONST0 } } "copy" { dict set localtypes $result $fromtype } "exists" { if {$fromtype == $NEXIST} { dict set localtypes $result $CONST0 } elseif {!($fromtype & $NEXIST)} { dict set localtypes $result $CONST1 } } "instanceOf" { if {[quadcode::dataType::isa $fromtype $totype]} { dict set localtypes $result $CONST1 } elseif {![quadcode::dataType::mightbea $fromtype $totype]} { dict set localtypes $result $CONST0 } } "jump" { my jt_processSuccessor $b $mask \ [lindex $result 1] $localtypes break } "jumpFalse" { set falsebranch [lindex $result 1] set truebranch [lindex $bb end 1 1] my jt_processCondBranch $b $mask \ $fromtype $truebranch $falsebranch $localtypes break } "jumpTrue" { set truebranch [lindex $result 1] set falsebranch [lindex $bb end 1 1] my jt_processCondBranch $b $mask \ $fromtype $truebranch $falsebranch $localtypes break } "jumpMaybe" { set failbranch [lindex $result 1] set okbranch [lindex $bb end 1 1] my jt_processJumpMaybe $b $mask \ $fromtype $failbranch $okbranch $localtypes break } "narrowToType" { dict set localtypes $result [expr {$fromtype & $totype}] } "purify" { dict set localtypes $result [expr {$fromtype & ~$IMPURE}] } default { # do nothing } } } return } # quadcode::transformer method jt_processCondBranch -- # # Updates the state when jump threading encounters a conditional # branch. # # Parameters: # b - Predecessor block # mask - Bit vector identifying assertions satisfied in the predecessor # otype - Type of the conditional jump operand # truebranch - Successor block if the operand is true # falsebranch - Successor block if the operand is false # localtypes - Dictionary giving types of variables that are # overridden by assertions made in jump threading. # # Results: # None. # # Side effects: # One or both successors is added to the successors of the block. oo::define quadcode::transformer method jt_processCondBranch {b mask otype truebranch falsebranch localtypes} { namespace upvar ::quadcode::dataType CONST0 CONST0 my debug-jumpthread { puts " block $b branches to $truebranch or $falsebranch" puts [format " and might be optimized based on %#llx (%s)" \ $otype [nameOfType $otype]] } # Include the true branch if it represents a possible condition if {[quadcode::dataType::isa $otype $CONST0]} { my debug-jumpthread { puts " branch to $truebranch cannot be taken" } } else { my jt_processSuccessor $b $mask $truebranch $localtypes } # Include the false branch if it represents a possible condition if {![quadcode::dataType::mightbea $otype $CONST0]} { my debug-jumpthread { puts " branch to $falsebranch cannot be taken" } } else { my jt_processSuccessor $b $mask $falsebranch $localtypes } return } # quadcode::transformer method jt_processJumpMaybe -- # # Updates the state when jump threading encounters a # jumpMaybe instruction # # Parameters: # b - Predecessor block # mask - Bit vector identifying assertions satisfied in the predecessor # otype - Type of the conditional jump operand # failbranch - Successor block if the operand represents a failure # okbranch - Successor block if the operand represents a success # localtypes - Dictionary giving types of variables that are # overridden by assertions made in jump threading. # # Results: # None. # # Side effects: # One or both successors is added to the successors of the block. oo::define quadcode::transformer method jt_processJumpMaybe {b mask otype failbranch okbranch localtypes} { namespace upvar ::quadcode::dataType FAIL FAIL my debug-jumpthread { puts " block $b branches to $failbranch or $okbranch" puts [format " and might be optimized based on %#llx (%s)" \ $otype [nameOfType $otype]] } # Include the true branch if it represents a possible condition if {[quadcode::dataType::isa $otype $FAIL]} { my debug-jumpthread { puts " branch to $okbranch cannot be taken" } } else { my jt_processSuccessor $b $mask $okbranch $localtypes } # Include the false branch if it represents a possible condition if {![quadcode::dataType::mightbea $otype $FAIL]} { my debug-jumpthread { puts " branch to $failbranch cannot be taken" } } else { my jt_processSuccessor $b $mask $failbranch $localtypes } return } # quadcode::transformer method jt_processSuccessor -- # # Updates the state when jump threading handles a jump that # proceeds from a given predecessor block to its successor. # # Parameters: # b - Predecessor block # mask - Bit vector identifying assertions satisfied in the predecessor # s - Successor block # localtypes - Dictionary giving types of variables that are # overridden by assertions made in jump threading. # # Results: # None. # # Side effects: # Determines the assertions satisfied in the successor block. # Records that set in the predecessor's 'jt_variants' record. # If the successor block has not yet been visited, creates a # 'jt_variants' record for it, and pushes the block onto 'jt_stack' # for processing. oo::define quadcode::transformer method jt_processSuccessor {b mask s localtypes} { my variable jt_variants my variable jt_stack # Find the assertion mask for the successor block set smask [my jt_assertionsToMask $b $mask $localtypes $s] my debug-jumpthread { puts [format { bb %s (%#llx) will be followed by %s (%#llx)} \ $b $mask $s $smask] } # If the successor block has not been seen, we will need subsequently # to process it. set vs [lindex $jt_variants $s] if {![dict exists $vs $smask]} { lset jt_variants $s {} dict set vs $smask {} lset jt_variants $s $vs lappend jt_stack $s $smask } # Record that the successor follows this block set vs [lindex $jt_variants $b] lset jt_variants $b {} dict set vs $mask $s $smask lset jt_variants $b $vs return } # quadcode::transformer method jt_maskToAssertions -- # # Takes the bitmask corresponding to the conditions asserted at the # entry to a basic block, and expands to a full dictionary of assertions # # Return value: # # Returns a dictionary var -> {kind type} -> cn # where var is the name of a variable # kind is 'is' or 'isnot' # type is the numeric code for a data type # cn is the condition's position in the set of conditions for b oo::define quadcode::transformer method jt_maskToAssertions {b mask} { my variable jt_antin set antin [lindex $jt_antin $b] set asserted {} my debug-jumpthread { puts [format " anticipated on entry to %s (%#llx):" $b $mask] } set cn -1 dict for {v conds} $antin { dict for {c -} $conds { incr cn my debug-jumpthread { puts " $cn: $v $c" } if {$mask & (1 << $cn)} { dict set asserted $v $c $cn } } } my debug-jumpthread { puts " asserted on entry:" set cn -1 dict for {v conds} $asserted { dict for {c -} $conds { incr cn puts " $cn: $v $c" } } } return $asserted } # quadcode::transformer method jt_applyAllAssertions -- # # Applies all the assertions that are active at the start of a block # and creates a dictionary holding narrowed types of variables # # Parameters: # asserted - Dictionary of the form var->{kind type}->cond# # where var is the name of a variable # kind is 'is' or 'isnot' # type is the numeric code for a data type # cond# is an ordinal number of the condition in a # block's list of conditions # # Results: # Returns a dictionary whose keys are variable names and whose # values are type codes of the narrowed data types. # # Used to calculate the initial data types of tracked variables on entry # to a block. oo::define quadcode:::transformer method jt_applyAllAssertions {asserted} { set localtypes {} my debug-jumpthread { puts " Type calculated on entry:" } foreach {v conds} $asserted { set globaltype [dict get $types $v] my debug-jumpthread { puts [format { %s global type %#llx (%s)} \ $v $globaltype [nameOfType $globaltype]] } set localtype [my jt_applyAssertions $globaltype $conds] dict set localtypes $v $localtype my debug-jumpthread { puts [format { %s local type %#llx (%s)} \ $v $localtype [nameOfType $localtype]] } } return $localtypes } # quadcode::transformer method jt_applyAssertions -- # # Apply assertions about a value to its type descriptor to produce # a narrowed type # # Parameters: # ty - Type to narrow # as - Assertions to apply, expressed as a dictionary: # {kind type}->cond# # where kind is 'is' or 'isnot' # type is the numeric code of a data type # cond# is the ordinal number of the condition among # the conditions applicable at the start of a block. # # Results: # Returns the narrowed type. oo::define quadcode::transformer method jt_applyAssertions {ty as} { namespace upvar ::quadcode::dataType \ ARRAY ARRAY FAIL FAIL IMPURE IMPURE NEXIST NEXIST dict for {c -} $as { lassign $c kind type switch -exact -- $kind { is { set mask $type } isnot { set mask [quadcode::dataType::allbut $type] } } if {$type & ~($ARRAY | $FAIL | $IMPURE | $NEXIST)} { set mask [expr {$mask | $IMPURE}] } set ty [expr {$ty & $mask}] } return $ty } # quadcode::transformer method jt_assertionsToMask # # Given a predecessor block, the types of objects assigned to in the # predecessor block, and a mask of anticipated conditions satisfied at # the entry to the predecessor block, determines the mask of assertions # satisfied at the entry to the successor block. # # Parameters: # p - Predecessor block # pmask - Bit vector specifying the anticipated conditions satisfied # at entry to block $p. # ptypes - Dictionary keyed by variable name giving the types of # values assigned in block $p # s - Successor block. # # Results: # Returns a bit vector of anticipated conditions satisfied at entry # to block $s. oo::define quadcode::transformer method jt_assertionsToMask {p pmask ptypes s} { my variable jt_antin my debug-pre { puts "\t make assertion mask for $p -> $s" } set smask 0 set cn -1 dict for {v conds} [lindex $jt_antin $s] { dict for {c -} $conds { incr cn if {[my jt_test_assertion $p $pmask $ptypes $s $v $c]} { my debug-pre { puts "\t include $v $c" } set smask [expr {$smask | (1 << $cn)}] } } } return $smask } # quadcode::transformer method jt_test_assertion -- # # Tests whether an anticipated condition is satisfied at the entry of # successor block $s from predecessor block $p. # # Parameters: # p - Predecssor block # pmask - Mask of bits indicating which of p's anticipated conditions # are satisfied. # ptypes - Dictionary whose keys are the names of values defined in p # and whose values are the types of the values. # s - Successor block # v - Variable name in the successor block # cond - Condition being tested # # Results: # Returns 1 if the condition is satisfied, 0 otherwise oo::define quadcode::transformer method jt_test_assertion {p pmask ptypes s v cond} { lassign $cond kind t # Find the name of the variable in the predecessor set w [my jt_translate_phi $s $v $p] if {[lindex $w 0] eq "literal"} { # The operand is a literal - extract its data type set u [::quadcode::typeOfLiteral [lindex $w 1]] } elseif {[dict exists $ptypes $w]} { # The operand is defined in the predecessor block, get its type set u [dict get $ptypes $w] } else { # The operand is not defined in the predecessor block, get its # conditions from the anticipable conditions in the predecessor return [my jt_masked_condition $p $pmask $w [list $kind $t]] } # We have the type of the operand created in the predecessor block. # Determine whether it satisfies the condition switch -exact -- $kind { is { return [my jt_type_is $u $t] } isnot { return [my jt_type_isnot $u $t] } default { return -code error error "bad condition $kind, can't happen" } } } # quadcode::transformer method jt_masked_condition -- # # Tests whether a block with a given mask of satisfied conditions # satisfies a particular named condition # # Parameters: # b - Block whose condition is being tested # mask - Bit mask indicating what numbered conditions are satisfied # v - Variable to which the desired condition applies # cond - Condition to test # # Results: # Returns 1 if the given condition is asserted, 0 otherwise. oo::define quadcode::transformer method jt_masked_condition {b mask v cond} { my variable jt_antin if {![dict exists $jt_antin $b $v $cond]} { # The condition is not anticipable in the predecessor. This # should not happen! return 0 } # The condition is anticipated in the predecessor. Find out whether # it is asserted there. set bit [dict get $jt_antin $b $v $cond] if {$mask & (1 << $bit)} { return 1 } else { return 0 } } # quadcode::transformer method jt_localtype -- # # Returns the type of a quadcode operand taking into account # local type assertions. # # Parameters: # opd - Operand being analyzed # localtypes - Dictionary giving locally asserted types of variables # # Results: # Returns the type of the operand, or 0 if the operand does not # represent a value. oo::define quadcode::transformer method jt_localtype {opd localtypes} { switch -exact -- [lindex $opd 0] { "literal" { return [quadcode::typeOfLiteral [lindex $opd 1]] } "temp" - "var" { if {[dict exists $localtypes $opd]} { return [dict get $localtypes $opd] } else { return [dict get $types $opd] } } default { return 0 } } } # quadcode::transformer method jt_type_is -- # # Tests whether one type is always an instance of another. # # Parameters: # u - Type being tested # v - Reference type # # Results: # Returns 1 if u is always an instance of t, 0 otherwise. # # Notes: # Ignores the IMPURE bit unless it is being tested specifically. oo::define quadcode::transformer method jt_type_is {u v} { namespace upvar ::quadcode::dataType IMPURE IMPURE if {($v == $IMPURE)} { return [expr {$u == $IMPURE}]; # Can't be true } elseif {[quadcode::dataType::isa $u $v]} { return 1 } else { return 0 } } # quadcode::transformer method jt_type_isnot -- # # Tests whether one type is never an instance of another. # # Parameters: # u - Type being tested # t - Reference type # # Results: # Returns 1 if u is never an instance of t, 0 otherwise. # # Notes: # Ignores the IMPURE bit unless it is being tested specifically. oo::define quadcode::transformer method jt_type_isnot {u v} { namespace upvar ::quadcode::dataType IMPURE IMPURE if {($v == $IMPURE)} { return [expr {($u & $IMPURE) == 0}]; # Can't be true } elseif {[quadcode::dataType::mightbea $u $v]} { return 0 } else { return 1 } } # quadcode::transformer method jt_cleanup -- # # Cleans up working storage after the jump threading pass. # # Results: |
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