88 lines
3.6 KiB
Factor
88 lines
3.6 KiB
Factor
USING: bit-arrays byte-arrays compiler.cfg compiler.cfg.instructions
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compiler.cfg.stack-frame help.markup help.syntax kernel math sequences ;
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IN: compiler.codegen.gc-maps
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HELP: emit-gc-info-bitmaps
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{ $values
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{ "gc-maps" sequence }
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{ "counts" "counts of the three different types of gc checks" }
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}
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{ $description "Emits the scrub location data in the 'gc-maps' to the make sequence being created. The result is a concatenation of all datastack scrub locations, retainstack scrub locations and gc root locations converted into a byte-array. Given that byte-array and knowledge of the number of scrub locations, the original gc-map can be reconstructed." } ;
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HELP: emit-scrub
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{ $values
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{ "seqs" "a sequence of sequences of 0/1" }
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{ "n" "length of the longest sequence" }
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}
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{ $description "Emits a space-efficient " { $link bit-array } " to the make sequence being created. The outputted array will be of length n times the number of sequences given. Each group of n elements in the array contains true values if the stack location should be scrubbed, and false if it shouldn't." }
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{ $examples
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{ $example
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"USING: bit-arrays byte-arrays compiler.codegen.gc-maps make prettyprint ;"
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"[ { B{ 0 } B{ 0 } B{ 1 1 1 0 } } emit-scrub ] ?{ } make . ."
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"?{ t f f f t f f f f f f t }\n4"
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}
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} ;
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{ emit-gc-info-bitmaps emit-scrub } related-words
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HELP: emit-uint
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{ $values { "n" integer } }
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{ $description "Emits an unsigned 32 bit integer to the make sequence being created. The word takes care of ensuring that the byte order is correct for the current machine." }
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{ $examples
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{ $example
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"USING: compiler.codegen.gc-maps make prettyprint ;"
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"[ 0xffff emit-uint ] B{ } make ."
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"B{ 255 255 0 0 }"
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}
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} ;
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HELP: emit-gc-maps
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{ $description "GC maps are emitted so that the end is aligned to a 16-byte boundary." } ;
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HELP: gc-maps
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{ $var-description "Variable that holds a sequence of " { $link gc-map } " tuples. Gc maps are added to the sequence by " { $link gc-map-here } "." } ;
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HELP: gc-map-needed?
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{ $values { "gc-map/f" { $maybe gc-map } } { "?" boolean } }
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{ $description "If all slots in the gc-map are empty, then it doesn't need to be emitted." } ;
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HELP: gc-root-offsets
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{ $values { "gc-map" gc-map } { "offsets" sequence } }
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{ $description "Gets the offets of all roots in a gc-map. The " { $link cfg } " variable must have been set and the stack-frame slot been initialized." } ;
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HELP: serialize-gc-maps
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{ $values { "byte-array" byte-array } }
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{ $description "Serializes the gc-maps that have been registered in the " { $link gc-maps } " variable into a byte-array." } ;
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HELP: gc-map-here
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{ $values { "gc-map" gc-map } }
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{ $description "Registers the gc map in the " { $link gc-maps } " dynamic variable at the current compiled offset." } ;
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ARTICLE: "compiler.codegen.gc-maps" "GC maps"
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"The " { $vocab-link "compiler.codegen.gc-maps" } " handles generating code for keeping track of garbage collection maps. Every code block either ends with:"
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{ $list "uint 0" }
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"or"
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{ $list
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{
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"bitmap, byte aligned, five subsequences:"
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{ $list
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"scrubbed data stack locations"
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"scrubbed retain stack locations"
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"GC root spill slots"
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}
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}
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"uint[] base pointers"
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"uint[] return addresses"
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"uint largest scrubbed data stack location"
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"uint largest scrubbed retain stack location"
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"uint largest GC root spill slot"
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"uint largest derived root spill slot"
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"int number of return addresses"
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}
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"The " { $link gc-map } " tuples of the " { $link cfg } " are serialized to the above format and placed directly after the generated code."
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$nl
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"Main entry point:"
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{ $subsections emit-gc-maps } ;
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ABOUT: "compiler.codegen.gc-maps"
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