70 lines
2.9 KiB
Factor
70 lines
2.9 KiB
Factor
USING: assocs compiler.cfg compiler.cfg.registers help.markup help.syntax math
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sequences ;
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IN: compiler.cfg.stacks.local
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HELP: replace-mapping
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{ $var-description "An " { $link assoc } " that maps from stack locations to virtual registers that were put on the stack." }
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{ $see-also replace-loc } ;
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HELP: current-height
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{ $class-description "A tuple used to keep track of the heights of the data and retain stacks in a " { $link basic-block } " The idea is that if the stack change instructions are tracked, then multiple changes can be folded into one. It has the following slots:"
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{ $table
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{ { $slot "d" } { "Current datastack height." } }
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{ { $slot "r" } { "Current retainstack height." } }
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{ { $slot "emit-d" } { "Queued up datastack height change." } }
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{ { $slot "emit-r" } { "Queued up retainstack height change." } }
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}
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} ;
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HELP: loc>vreg
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{ $values { "loc" loc } { "vreg" "virtual register" } }
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{ $description "Maps a stack location to a virtual register." } ;
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HELP: replace-loc
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{ $values { "vreg" "virtual register" } { "loc" loc } }
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{ $description "Registers that the absolute stack location " { $snippet "loc" } " should be overwritten with the contents of the virtual register." } ;
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HELP: peek-loc
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{ $values { "loc" loc } { "vreg" "virtaul register" } }
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{ $description "Retrieves the virtual register and the given stack location." } ;
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HELP: translate-local-loc
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{ $values { "loc" loc } { "loc'" loc } }
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{ $description "Translates an absolute stack location to one that is relative to the current stacks height as given in " { $link current-height } "." }
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{ $examples
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{ $example
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"USING: compiler.cfg.stacks.local compiler.cfg.registers compiler.cfg.debugger namespaces prettyprint ;"
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"T{ current-height { d 3 } } current-height set D 7 translate-local-loc ."
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"D 4"
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}
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} ;
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HELP: height-changes
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{ $values { "current-height" current-height } { "insns" sequence } }
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{ $description "Converts a " { $link current-height } " tuple to 0-2 stack height change instructions." }
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{ $examples
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{ $example
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"USING: compiler.cfg.stacks.local ;"
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"T{ current-height { emit-d 4 } { emit-r -2 } } height-changes ."
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"{ T{ ##inc-d { n 4 } } T{ ##inc-r { n -2 } } }"
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}
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} ;
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HELP: emit-changes
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{ $description "! Insert height and stack changes prior to the last instruction." } ;
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HELP: inc-d
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{ $values { "n" number } }
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{ $description "Increases or decreases the current datastacks height." } ;
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ARTICLE: "compiler.cfg.stacks.local" "Local stack analysis"
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"Local stack analysis. We build three sets for every basic block in the CFG:"
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{ $list
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"peek-set: all stack locations that the block reads before writing"
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"replace-set: all stack locations that the block writes"
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"kill-set: all stack locations which become unavailable after the block ends because of the stack height being decremented" }
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"This is done while constructing the CFG." ;
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ABOUT: "compiler.cfg.stacks.local"
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