38 lines
1.6 KiB
OCaml
38 lines
1.6 KiB
OCaml
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open Ll
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open Datastructures
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(* Because the cfg instance of the dataflow graph uses _basic blocks_ as nodes,
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we need a way to recover the dataflow facts at individual instructions
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within the block. Depending on the direction of the analysis, this amounts to
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propagating information either forward or backwards through the block.
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The following helper functions construct maps from each instruction or terminator
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to the corresponding dataflow fact. *)
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(* Compute IN for each instruction in a block, given IN of the first instruction *)
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let block_flow_forwards_map (fi:uid * insn -> 'd -> 'd)
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(ft:terminator -> 'd -> 'd)
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({insns; term}:block) (d_in:'d) : uid -> 'd =
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let t_id, t = term in
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let m, d_tmn = List.fold_left (fun (m, d) (u,i) ->
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let d' = fi (u,i) d in
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UidM.add u d m, d')
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(UidM.empty, d_in) insns in
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let m' = UidM.add t_id d_tmn m in
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fun u -> UidM.find u m'
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(* Compute OUT for each instruction in a block, given OUT of the terminator*)
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let block_flow_backwards_map (fi:uid * insn -> 'd -> 'd)
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(ft:terminator -> 'd -> 'd)
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({insns; term}:block) (d_out:'d) : uid -> 'd =
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let t_id, t = term in
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let d_ins = ft t d_out in
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let m, _ = List.fold_right (fun (u,i) (m, d) ->
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let d' = fi (u,i) d in
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UidM.add u d m, d')
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insns (UidM.empty, d_ins) in
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let m' = UidM.add t_id d_out m in
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fun u -> UidM.find u m'
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