lustrec / src / optimize_machine.ml @ cf78a589
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open LustreSpec |
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open Corelang |
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open Machine_code |
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|
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let rec eliminate elim instr = |
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let e_expr = eliminate_expr elim in |
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match instr with |
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| MLocalAssign (i,v) -> MLocalAssign (i, e_expr v) |
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| MStateAssign (i,v) -> MStateAssign (i, e_expr v) |
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| MReset i -> instr |
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| MStep (il, i, vl) -> MStep(il, i, List.map e_expr vl) |
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| MBranch (g,hl) -> |
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MBranch |
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(e_expr g, |
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(List.map |
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(fun (l, il) -> l, List.map (eliminate elim) il) |
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hl |
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) |
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) |
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|
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and eliminate_expr elim expr = |
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match expr with |
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| LocalVar v -> if List.mem_assoc v elim then List.assoc v elim else expr |
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| Fun (id, vl) -> Fun (id, List.map (eliminate_expr elim) vl) |
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| Array(vl) -> Array(List.map (eliminate_expr elim) vl) |
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| Access(v1, v2) -> Access(eliminate_expr elim v1, eliminate_expr elim v2) |
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| Power(v1, v2) -> Access(eliminate_expr elim v1, eliminate_expr elim v2) |
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| Cst _ | StateVar _ -> expr |
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|
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(* see if elim has to take in account the provided instr: |
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if so, upodate elim and return the remove flag, |
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otherwise, the expression should be kept and elim is left untouched *) |
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let update_elim elim instr = |
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Format.eprintf "SHOULD WE STORE THE EXPRESSION IN INSTR %a TO ELIMINATE IT@." pp_instr instr; |
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|
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let apply elim v new_e = |
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(v, new_e)::List.map (fun (v, e) -> v, eliminate_expr [v, new_e] e) elim |
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in |
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match instr with |
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(* Simple cases*) |
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| MLocalAssign (v, (Cst _ as e)) |
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| MLocalAssign (v, (LocalVar _ as e)) |
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| MLocalAssign (v, (StateVar _ as e)) -> true, apply elim v e |
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(* When optimization >= 3, we also inline any basic operator call. |
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All those are returning a single ouput *) |
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| MStep([v], id, vl) when |
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List.mem id Basic_library.internal_funs |
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&& !Options.optimization >= 3 |
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-> assert false |
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(* true, apply elim v (Fun(id, vl))*) |
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|
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|
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| MLocalAssign (v, ((Fun (id, il)) as e)) when |
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List.mem id Basic_library.internal_funs (* this will avoid inlining ite *) |
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&& !Options.optimization >= 3 |
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-> ( |
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Format.eprintf "WE STORE THE EXPRESSION DEFINING %s TO ELIMINATE IT@." v.var_id; |
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true, apply elim v e |
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) |
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| _ -> |
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(* default case, we keep the instruction and do not modify elim *) |
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false, elim |
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|
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|
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(** We iterate in the order, recording simple local assigns in an accumulator |
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1. each expression is rewritten according to the accumulator |
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2. local assigns then rewrite occurrences of the lhs in the computed accumulator |
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*) |
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let optimize_minstrs instrs = |
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let rev_instrs, eliminate = |
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List.fold_left (fun (rinstrs, elim) instr -> |
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(* each subexpression in instr that could be rewritten by the elim set is |
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rewritten *) |
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let instr = eliminate elim instr in |
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(* if instr is a simple local assign, then (a) elim is simplified with it (b) it |
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is stored as the elim set *) |
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let remove, elim = update_elim elim instr in |
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(if remove then rinstrs else instr::rinstrs), elim |
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) ([],[]) instrs |
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in |
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let eliminated_vars = List.map fst eliminate in |
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eliminated_vars, List.rev rev_instrs |
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|
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(** Perform optimization on machine code: |
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- iterate through step instructions and remove simple local assigns |
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|
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*) |
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let optimize_machine machine = |
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let eliminated_vars, new_instrs = optimize_minstrs machine.mstep.step_instrs in |
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let new_locals = |
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List.filter (fun v -> not (List.mem v eliminated_vars)) machine.mstep.step_locals |
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in |
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{ |
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machine with |
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mstep = { |
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machine.mstep with |
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step_locals = new_locals; |
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step_instrs = new_instrs |
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} |
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} |
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|
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|
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|
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let optimize_machines machines = |
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List.map optimize_machine machines |
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|
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|
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(* Local Variables: *) |
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(* compile-command:"make -C .." *) |
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(* End: *) |