264 lines
9.2 KiB
OCaml
264 lines
9.2 KiB
OCaml
(***********************************************************************)
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(* *)
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(* OCaml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 2000 Institut National de Recherche en Informatique et *)
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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the Q Public License version 1.0. *)
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(* *)
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(***********************************************************************)
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(* Instruction selection for the AMD64 *)
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open Arch
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open Proc
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open Cmm
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open Mach
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(* Auxiliary for recognizing addressing modes *)
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type addressing_expr =
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Asymbol of string
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| Alinear of expression
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| Aadd of expression * expression
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| Ascale of expression * int
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| Ascaledadd of expression * expression * int
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let rec select_addr exp =
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match exp with
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Cconst_symbol s when not !Clflags.dlcode ->
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(Asymbol s, 0)
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| Cop((Caddi | Cadda), [arg; Cconst_int m]) ->
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let (a, n) = select_addr arg in (a, n + m)
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| Cop((Csubi | Csuba), [arg; Cconst_int m]) ->
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let (a, n) = select_addr arg in (a, n - m)
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| Cop((Caddi | Cadda), [Cconst_int m; arg]) ->
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let (a, n) = select_addr arg in (a, n + m)
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| Cop(Clsl, [arg; Cconst_int(1|2|3 as shift)]) ->
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begin match select_addr arg with
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(Alinear e, n) -> (Ascale(e, 1 lsl shift), n lsl shift)
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| _ -> (Alinear exp, 0)
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end
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| Cop(Cmuli, [arg; Cconst_int(2|4|8 as mult)]) ->
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begin match select_addr arg with
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(Alinear e, n) -> (Ascale(e, mult), n * mult)
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| _ -> (Alinear exp, 0)
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end
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| Cop(Cmuli, [Cconst_int(2|4|8 as mult); arg]) ->
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begin match select_addr arg with
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(Alinear e, n) -> (Ascale(e, mult), n * mult)
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| _ -> (Alinear exp, 0)
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end
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| Cop((Caddi | Cadda), [arg1; arg2]) ->
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begin match (select_addr arg1, select_addr arg2) with
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((Alinear e1, n1), (Alinear e2, n2)) ->
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(Aadd(e1, e2), n1 + n2)
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| ((Alinear e1, n1), (Ascale(e2, scale), n2)) ->
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(Ascaledadd(e1, e2, scale), n1 + n2)
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| ((Ascale(e1, scale), n1), (Alinear e2, n2)) ->
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(Ascaledadd(e2, e1, scale), n1 + n2)
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| (_, (Ascale(e2, scale), n2)) ->
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(Ascaledadd(arg1, e2, scale), n2)
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| ((Ascale(e1, scale), n1), _) ->
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(Ascaledadd(arg2, e1, scale), n1)
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| _ ->
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(Aadd(arg1, arg2), 0)
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end
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| arg ->
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(Alinear arg, 0)
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(* Special constraints on operand and result registers *)
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exception Use_default
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let rax = phys_reg 0
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let rcx = phys_reg 5
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let rdx = phys_reg 4
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let pseudoregs_for_operation op arg res =
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match op with
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(* Two-address binary operations: arg.(0) and res.(0) must be the same *)
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Iintop(Iadd|Isub|Imul|Iand|Ior|Ixor) | Iaddf|Isubf|Imulf|Idivf ->
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([|res.(0); arg.(1)|], res)
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(* One-address unary operations: arg.(0) and res.(0) must be the same *)
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| Iintop_imm((Iadd|Isub|Imul|Iand|Ior|Ixor|Ilsl|Ilsr|Iasr), _)
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| Iabsf | Inegf
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| Ispecific(Ibswap (32|64)) ->
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(res, res)
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(* For xchg, args must be a register allowing access to high 8 bit register
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(rax, rbx, rcx or rdx). Keep it simple, just force the argument in rax. *)
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| Ispecific(Ibswap 16) ->
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([| rax |], [| rax |])
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| Ispecific(Ifloatarithmem(_,_)) ->
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let arg' = Array.copy arg in
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arg'.(0) <- res.(0);
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(arg', res)
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(* For shifts with variable shift count, second arg must be in rcx *)
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| Iintop(Ilsl|Ilsr|Iasr) ->
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([|res.(0); rcx|], res)
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(* For div and mod, first arg must be in rax, rdx is clobbered,
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and result is in rax or rdx respectively.
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Keep it simple, just force second argument in rcx. *)
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| Iintop(Idiv) ->
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([| rax; rcx |], [| rax |])
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| Iintop(Imod) ->
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([| rax; rcx |], [| rdx |])
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(* For div and mod with immediate operand, arg must not be in rax.
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Keep it simple, force it in rdx. *)
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| Iintop_imm((Idiv|Imod), _) ->
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([| rdx |], [| rdx |])
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(* Other instructions are regular *)
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| _ -> raise Use_default
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let inline_ops =
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[ "sqrt"; "caml_bswap16_direct"; "caml_int32_direct_bswap";
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"caml_int64_direct_bswap"; "caml_nativeint_direct_bswap" ]
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(* The selector class *)
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class selector = object (self)
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inherit Selectgen.selector_generic as super
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method is_immediate n = n <= 0x7FFFFFFF && n >= -0x80000000
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method is_immediate_natint n = n <= 0x7FFFFFFFn && n >= -0x80000000n
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method! is_simple_expr e =
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match e with
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| Cop(Cextcall(fn, _, _, _), args)
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when List.mem fn inline_ops ->
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(* inlined ops are simple if their arguments are *)
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List.for_all self#is_simple_expr args
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| _ ->
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super#is_simple_expr e
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method select_addressing chunk exp =
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let (a, d) = select_addr exp in
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(* PR#4625: displacement must be a signed 32-bit immediate *)
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if d < -0x8000_0000 || d > 0x7FFF_FFFF
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then (Iindexed 0, exp)
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else match a with
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| Asymbol s ->
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(Ibased(s, d), Ctuple [])
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| Alinear e ->
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(Iindexed d, e)
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| Aadd(e1, e2) ->
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(Iindexed2 d, Ctuple[e1; e2])
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| Ascale(e, scale) ->
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(Iscaled(scale, d), e)
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| Ascaledadd(e1, e2, scale) ->
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(Iindexed2scaled(scale, d), Ctuple[e1; e2])
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method! select_store addr exp =
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match exp with
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Cconst_int n when self#is_immediate n ->
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(Ispecific(Istore_int(Nativeint.of_int n, addr)), Ctuple [])
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| Cconst_natint n when self#is_immediate_natint n ->
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(Ispecific(Istore_int(n, addr)), Ctuple [])
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| Cconst_pointer n when self#is_immediate n ->
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(Ispecific(Istore_int(Nativeint.of_int n, addr)), Ctuple [])
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| Cconst_natpointer n when self#is_immediate_natint n ->
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(Ispecific(Istore_int(n, addr)), Ctuple [])
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| Cconst_symbol s when not (!pic_code || !Clflags.dlcode) ->
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(Ispecific(Istore_symbol(s, addr)), Ctuple [])
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| _ ->
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super#select_store addr exp
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method! select_operation op args =
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match op with
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(* Recognize the LEA instruction *)
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Caddi | Cadda | Csubi | Csuba ->
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begin match self#select_addressing Word (Cop(op, args)) with
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(Iindexed d, _) -> super#select_operation op args
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| (Iindexed2 0, _) -> super#select_operation op args
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| (addr, arg) -> (Ispecific(Ilea addr), [arg])
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end
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(* Recognize (x / cst) and (x % cst) only if cst is a power of 2. *)
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| Cdivi ->
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begin match args with
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[arg1; Cconst_int n] when self#is_immediate n
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&& n = 1 lsl (Misc.log2 n) ->
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(Iintop_imm(Idiv, n), [arg1])
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| _ -> (Iintop Idiv, args)
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end
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| Cmodi ->
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begin match args with
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[arg1; Cconst_int n] when self#is_immediate n
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&& n = 1 lsl (Misc.log2 n) ->
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(Iintop_imm(Imod, n), [arg1])
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| _ -> (Iintop Imod, args)
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end
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(* Recognize float arithmetic with memory. *)
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| Caddf ->
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self#select_floatarith true Iaddf Ifloatadd args
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| Csubf ->
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self#select_floatarith false Isubf Ifloatsub args
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| Cmulf ->
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self#select_floatarith true Imulf Ifloatmul args
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| Cdivf ->
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self#select_floatarith false Idivf Ifloatdiv args
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| Cextcall("sqrt", _, false, _) ->
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begin match args with
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[Cop(Cload (Double|Double_u as chunk), [loc])] ->
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let (addr, arg) = self#select_addressing chunk loc in
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(Ispecific(Ifloatsqrtf addr), [arg])
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| [arg] ->
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(Ispecific Isqrtf, [arg])
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| _ ->
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assert false
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end
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(* Recognize store instructions *)
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| Cstore Word ->
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begin match args with
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[loc; Cop(Caddi, [Cop(Cload _, [loc']); Cconst_int n])]
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when loc = loc' && self#is_immediate n ->
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let (addr, arg) = self#select_addressing Word loc in
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(Ispecific(Ioffset_loc(n, addr)), [arg])
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| _ ->
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super#select_operation op args
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end
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| Cextcall("caml_bswap16_direct", _, _, _) ->
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(Ispecific (Ibswap 16), args)
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| Cextcall("caml_int32_direct_bswap", _, _, _) ->
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(Ispecific (Ibswap 32), args)
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| Cextcall("caml_int64_direct_bswap", _, _, _)
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| Cextcall("caml_nativeint_direct_bswap", _, _, _) ->
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(Ispecific (Ibswap 64), args)
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| _ -> super#select_operation op args
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(* Recognize float arithmetic with mem *)
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method select_floatarith commutative regular_op mem_op args =
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match args with
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[arg1; Cop(Cload (Double|Double_u as chunk), [loc2])] ->
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let (addr, arg2) = self#select_addressing chunk loc2 in
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(Ispecific(Ifloatarithmem(mem_op, addr)),
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[arg1; arg2])
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| [Cop(Cload (Double|Double_u as chunk), [loc1]); arg2] when commutative ->
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let (addr, arg1) = self#select_addressing chunk loc1 in
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(Ispecific(Ifloatarithmem(mem_op, addr)),
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[arg2; arg1])
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| [arg1; arg2] ->
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(regular_op, [arg1; arg2])
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| _ ->
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assert false
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(* Deal with register constraints *)
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method! insert_op_debug op dbg rs rd =
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try
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let (rsrc, rdst) = pseudoregs_for_operation op rs rd in
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self#insert_moves rs rsrc;
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self#insert_debug (Iop op) dbg rsrc rdst;
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self#insert_moves rdst rd;
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rd
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with Use_default ->
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super#insert_op_debug op dbg rs rd
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end
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let fundecl f = (new selector)#emit_fundecl f
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