63 lines
3.0 KiB
Factor
63 lines
3.0 KiB
Factor
USING: assocs compiler.cfg compiler.cfg.instructions
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compiler.cfg.linear-scan.allocation compiler.cfg.linear-scan.allocation.state
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compiler.cfg.linear-scan.live-intervals cpu.architecture hashtables help.markup
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help.syntax kernel sequences ;
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IN: compiler.cfg.linear-scan.allocation
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HELP: (allocate-registers)
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{ $values { "unhandled-min-heap" "stuff" } }
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{ $description "Register allocation works by emptying the unhandled intervals and sync points." } ;
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HELP: active-positions
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{ $values { "new" live-interval-state } { "assoc" assoc } }
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{ $description "Looks at the " { $link active-intervals } " and sets to 0 those registers in 'assoc' that can't be used for allocation." } ;
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HELP: allocate-registers
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{ $values
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{ "intervals/sync-points" sequence }
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{ "registers" assoc }
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{ "live-intervals'" sequence }
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}
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{ $description "Performs register allocation of a " { $link sequence } " of live intervals. Each live interval is assigned a physical register and also a spill slot if it needs to be spilled." } ;
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HELP: assign-register
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{ $values { "new" live-interval-state } { "registers" assoc } }
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{ $description "Assigns a processor register to the live interval." } ;
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HELP: free-positions
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{ $values { "registers" assoc } { "reg-class" { $or int-regs float-regs } } { "avail-registers" assoc } }
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{ $description "Creates an alist mapping registers to their desirability for allocation. 'avail-registers' is an alist and not a " { $link hashtable } " because the register allocation order is significant." }
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{ $see-also register-status } ;
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HELP: handle-sync-point
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{ $values
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{ "sync-point" sync-point }
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{ "active-intervals" assoc }
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}
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{ $description "Removes from 'active-intervals' all intervals that were spilled at the sync point. Most of the time, all intervals are spilled. But it depends on if the sync point was constructed from a " { $link clobber-insn } " or " { $link hairy-clobber-insn } "." } ;
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HELP: spill-at-sync-point
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{ $values
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{ "sync-point" sync-point }
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{ "live-interval" live-interval-state }
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{ "?" boolean }
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}
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{ $description "Maybe spills the live-interval at the given sync point. If the interval was spilled, then " { $link f } " is put on the stack to indicate that the interval isn't live anymore, " { $link t } " otherwise." }
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{ $see-also spill-at-sync-point? } ;
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HELP: spill-at-sync-point?
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{ $values
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{ "sync-point" sync-point }
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{ "live-interval" live-interval-state }
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{ "?" boolean }
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}
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{ $description "Whether the given live interval must be spilled at the sync point. If the instruction for the given sync point is a " { $link hairy-clobber-insn } ", such as a (" { $link ##call-gc } " instruction) then the interval is always spilled." } ;
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ARTICLE: "compiler.cfg.linear-scan.allocation" "Allocating registers for live intervals"
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"This vocab implements the step in the linear scan algorithm in which virtual registers are allocated physical registers. It also takes decisions on when to spill registers."
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$nl
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"Main entry point:"
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{ $subsections allocate-registers } ;
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ABOUT: "compiler.cfg.linear-scan.allocation"
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