(************************************************************************) (* * The Rocq Prover / The Rocq Development Team *) (* v * Copyright INRIA, CNRS and contributors *) (* <O___,, * (see version control and CREDITS file for authors & dates) *) (* \VV/ **************************************************************) (* // * This file is distributed under the terms of the *) (* * GNU Lesser General Public License Version 2.1 *) (* * (see LICENSE file for the text of the license) *) (************************************************************************)
(* Author: Benjamin Grégoire as part of the bytecode-based virtual reduction
machine, Oct 2004 *) (* Extension: Arnaud Spiwack (support for native arithmetic), May 2005 *)
open Names open Vmvalues open Vmbytecodes open Vmopcodes open Mod_subst open CPrimitives
(* Relocation information *) type reloc_info =
| Reloc_annot of annot_switch
| Reloc_const of structured_constant
| Reloc_getglobal of Names.Constant.t
| Reloc_caml_prim of caml_prim
let hash_reloc_info r = letopen Hashset.Combine in match r with
| Reloc_annot sw -> combinesmall 1 (hash_annot_switch sw)
| Reloc_const c -> combinesmall 2 (hash_structured_constant c)
| Reloc_getglobal c -> combinesmall 3 (Constant.CanOrd.hash c)
| Reloc_caml_prim p -> combinesmall 4 (CPrimitives.hash (caml_prim_to_prim p))
module RelocTable = Hashtbl.Make(struct type t = reloc_info let equal = eq_reloc_info let hash = hash_reloc_info end)
module Positions : sig type t val of_list : int list -> t val iter : (int -> unit) -> t -> unit end = struct
type t = string (* Represent an ordered set of 32-bit integers as an array of successive diffs. We use furthermore an approach where smaller integers use less bytes. Numbers smaller than 255 are stored into one byte. Otherwise we use the byte 0x00 to signal that we store the integer in the next 4 bytes. This is a cheap way to
compact this data. *)
let output buf n = if n <= 0xFF then Buffer.add_uint8 buf n else let () = Buffer.add_uint8 buf 0x00 in
Buffer.add_int32_be buf (Int32.of_int n)
let input s pos = let c = Char.code s.[!pos] in if Int.equal c 0x00 then let c = String.get_int32_be s (!pos+1) in let () = pos := !pos + 5 in
Int32.to_int c else let () = pos := !pos + 1 in
c
let of_list l = match l with
| [] -> ""
| n :: l -> let buf = Buffer.create 16 in let () = assert (0 < n) in let () = output buf n in let rec aux cur l = match l with
| [] -> ()
| n :: l -> let () = assert (cur < n) in let () = output buf (n - cur) in
aux n l in let () = aux n l in
Buffer.contents buf
let iter f s = let pos = ref 0 in let len = String.length s in let cur = ref 0 in while !pos < len do let n = input s pos in let () = cur := n + !cur in
f !cur
done
end
module NonSubstReloc = struct
(** Relocations that are left untouched by module substitution. To reduce the
memory footprint, this data is kept on the VM segment. *) type t =
| SReloc_Const_sort of Sorts.t
| SReloc_Const_evar of Evar.t
| SReloc_Const_b0 of tag
| SReloc_Const_univ_instance of UVars.Instance.t
| SReloc_Const_val of structured_values
| SReloc_Const_uint of Uint63.t
| SReloc_Const_float of Float64.t
| SReloc_Const_string of Pstring.t
| SReloc_annot of annot_switch
| SReloc_caml_prim of caml_prim
let to_reloc = function
| SReloc_Const_sort s -> Reloc_const (Const_sort s)
| SReloc_Const_evar e -> Reloc_const (Const_evar e)
| SReloc_Const_b0 tag -> Reloc_const (Const_b0 tag)
| SReloc_Const_univ_instance u -> Reloc_const (Const_univ_instance u)
| SReloc_Const_val v -> Reloc_const (Const_val v)
| SReloc_Const_uint i -> Reloc_const (Const_uint i)
| SReloc_Const_float f -> Reloc_const (Const_float f)
| SReloc_Const_string s -> Reloc_const (Const_string s)
| SReloc_annot annot -> Reloc_annot annot
| SReloc_caml_prim prm -> Reloc_caml_prim prm
end
module Reloc = struct
type t =
| SReloc_Const_ind of inductive
| SReloc_getglobal of Names.Constant.t
| SReloc_indirect of int (* index in the non-subst table *)
let to_reloc table = function
| SReloc_Const_ind ind -> Reloc_const (Const_ind ind)
| SReloc_getglobal cst -> Reloc_getglobal cst
| SReloc_indirect i -> NonSubstReloc.to_reloc table.(i)
let subst s reloc = match reloc with
| SReloc_Const_ind ind -> let ind' = Mod_subst.subst_ind s ind in if ind' == ind then reloc else SReloc_Const_ind ind'
| SReloc_getglobal cst -> let cst' = Mod_subst.subst_constant s cst in if cst' == cst then reloc else SReloc_getglobal cst'
| SReloc_indirect _ -> reloc
end
(* Most of the words of the bytecode are comprised of a byte followed by three nul bytes. It is compressed as follows. In the common case, only the byte is output. In the other cases (or when the byte is too large), 255 is output followed by the four original bytes, or 254 is output followed by the first
three original bytes (assuming the fourth is nul), or 253 or 252. *)
let compress_code src sz = let buf = Buffer.create (sz * 3 / 8) in
for i = 0 to sz / 4 - 1 do let c01 = Bytes.get_uint16_le src (i * 4) in let c23 = Bytes.get_uint16_le src (i * 4 + 2) in if c23 = 0 then if c01 < 252 then
Buffer.add_uint8 buf c01 else begin
Buffer.add_uint8 buf 253;
Buffer.add_uint16_le buf c01; end elseif c23 = 0xffff && c01 >= 0xff00 then begin
Buffer.add_uint8 buf 252;
Buffer.add_uint8 buf c01; end elseif c23 <= 0xff then begin
Buffer.add_uint8 buf 254;
Buffer.add_uint16_le buf c01;
Buffer.add_uint8 buf c23; end else begin
Buffer.add_uint8 buf 255;
Buffer.add_uint16_le buf c01;
Buffer.add_uint16_le buf c23; end
done;
Buffer.contents buf
let decompress_code src = let sz = String.length src in let buf = Buffer.create (sz * 4) in let i = ref 0 in while !i < sz do let c01, c23 = matchString.get src !i with
| '\000' .. '\251' as c ->
i := !i + 1;
(Char.code c, 0)
| '\252' ->
i := !i + 2;
(String.get_uint8 src (!i - 1) + 0xff00, 0xffff)
| '\253' ->
i := !i + 3;
(String.get_uint16_le src (!i - 2), 0)
| '\254' ->
i := !i + 4;
(String.get_uint16_le src (!i - 3), String.get_uint8 src (!i - 1))
| '\255' ->
i := !i + 5;
(String.get_uint16_le src (!i - 4), String.get_int16_le src (!i - 2)) in
Buffer.add_uint16_le buf c01;
Buffer.add_uint16_le buf c23;
done;
Buffer.to_bytes buf
let patch_int tp reloc = let buff = decompress_code tp.tp_code in let iter pos = let id = Bytes.get_int32_le buff pos in let reloc = reloc.(Int32.to_int id) in
Bytes.set_int32_le buff pos (Int32.of_int reloc) in let () = Positions.iter iter tp.tp_pos in
buff
let patch (tp, pl) f = let f r = f (Reloc.to_reloc tp.tp_reloc r) in let reloc = CArray.map_left f pl.reloc_infos in let buff = patch_int tp reloc in
tcode_of_code buff, tp.tp_fv
(* Buffering of bytecode *)
type label_definition =
Label_defined of int
| Label_undefined of (int * int) list
type env = {
mutable out_buffer : Bytes.t;
mutable out_position : int;
mutable reloc_pos : int list;
mutable reloc_id : int;
mutable label_table : label_definition array; (* i-th table element = Label_defined n means that label i was already encountered and lives at offset n i-th table element = Label_undefined l means that the label was not encountered yet, first integer is the location of the value to be patched
in the string, seconed one is its origin *)
reloc_info : int RelocTable.t;
}
let out_word env b1 b2 b3 b4 = let p = env.out_position in let buf = let len = Bytes.length env.out_buffer in if p + 3 < len then env.out_buffer else let new_len = min (Sys.max_string_length) (2 * len) in (* Not the right exception... *) let () = ifnot (p + 3 < new_len) then Vmerrors.too_large_code() in let new_buffer = Bytes.create new_len in let () = Bytes.blit env.out_buffer 0 new_buffer 0 len in let () = env.out_buffer <- new_buffer in
new_buffer in let () = Bytes.set_uint8 buf p b1 in let () = Bytes.set_uint8 buf (p + 1) b2 in let () = Bytes.set_uint8 buf (p + 2) b3 in let () = Bytes.set_uint8 buf (p + 3) b4 in
env.out_position <- p + 4
let out env opcode =
out_word env opcode 0 0 0
let is_immed i = Uint63.le (Uint63.of_int i) Uint63.maxuint31
(* Detect whether the current value of the accu register is no longer needed (i.e., the register is written before being read). If so, the
register can be used freely; no need to save and restore it. *) let is_accu_dead = function
| [] -> false
| c :: _ -> match c with
| Kacc _ | Kenvacc _ | Kconst _ | Koffsetclosure _ | Kgetglobal _ -> true
| _ -> false
let out_int env n =
out_word env n (n asr 8) (n asr 16) (n asr 24)
(* Handling of local labels and backpatching *)
let extend_label_table env needed = let new_size = ref(Array.length env.label_table) in while needed >= !new_size do new_size := 2 * !new_size done; let new_table = Array.make !new_size (Label_undefined []) in
Array.blit env.label_table 0 new_table 0 (Array.length env.label_table);
env.label_table <- new_table
let backpatch env (pos, orig) = let displ = (env.out_position - orig) asr 2 in
Bytes.set_int32_le env.out_buffer pos (Int32.of_int displ)
let define_label env lbl = if lbl >= Array.length env.label_table then extend_label_table env lbl; match (env.label_table).(lbl) with
Label_defined _ -> raise(Failure "CEmitcode.define_label")
| Label_undefined patchlist -> List.iter (fun p -> backpatch env p) patchlist;
(env.label_table).(lbl) <- Label_defined env.out_position
let out_label_with_orig env orig lbl = if lbl >= Array.length env.label_table then extend_label_table env lbl; match (env.label_table).(lbl) with
Label_defined def ->
out_int env ((def - orig) asr 2)
| Label_undefined patchlist ->
(env.label_table).(lbl) <-
Label_undefined((env.out_position, orig) :: patchlist);
out_int env 0
let out_label env l = out_label_with_orig env env.out_position l
(* Relocation information *)
let enter env info = let pos = env.out_position in let () = env.reloc_pos <- pos :: env.reloc_pos in try RelocTable.find env.reloc_info info with Not_found -> let id = env.reloc_id in let () = env.reloc_id <- id + 1 in let () = RelocTable.add env.reloc_info info id in
id
let slot_for env r = out_int env (enter env r)
let slot_for_const env c = slot_for env (Reloc_const c) let slot_for_annot env a = slot_for env (Reloc_annot a) let slot_for_getglobal env p = slot_for env (Reloc_getglobal p) let slot_for_caml_prim env op = slot_for env (Reloc_caml_prim op)
let inplace_prim_op = function
| Float64next_up | Float64next_down -> true
| _ -> false
let check_prim_op_inplace = function
| Float64next_up -> opCHECKNEXTUPFLOATINPLACE
| Float64next_down -> opCHECKNEXTDOWNFLOATINPLACE
| _ -> assert false
let emit_instr env = function
| Klabel lbl -> define_label env lbl
| Kacc n -> if n < 8 then out env(opACC0 + n) else (out env opACC; out_int env n)
| Kenvacc n -> if n >= 0 && n <= 3 then out env(opENVACC0 + n) else (out env opENVACC; out_int env n)
| Koffsetclosure ofs -> if Int.equal ofs 0 || Int.equal ofs 1 then out env (opOFFSETCLOSURE0 + ofs) else (out env opOFFSETCLOSURE; out_int env ofs)
| Kpush ->
out env opPUSH
| Kpop n ->
out env opPOP; out_int env n
| Kpush_retaddr lbl ->
out env opPUSH_RETADDR; out_label env lbl
| Kshort_apply n ->
assert (1 <= n && n <= 4);
out env(opAPPLY1 + n - 1)
| Kapply n ->
out env opAPPLY; out_int env n
| Kappterm(n, sz) -> if n < 4 then (out env(opAPPTERM1 + n - 1); out_int env sz) else (out env opAPPTERM; out_int env n; out_int env sz)
| Kreturn n ->
out env opRETURN; out_int env n
| Kjump ->
out env opRETURN; out_int env 0
| Krestart ->
out env opRESTART
| Kgrab n ->
out env opGRAB; out_int env n
| Kgrabrec(rec_arg) ->
out env opGRABREC; out_int env rec_arg
| Kclosure(lbl, n) ->
out env opCLOSURE; out_int env n; out_label env lbl
| Kclosurerec(nfv,init,lbl_types,lbl_bodies) ->
out env opCLOSUREREC;out_int env (Array.length lbl_bodies);
out_int env nfv; out_int env init; let org = env.out_position in
Array.iter (out_label_with_orig env org) lbl_types; let org = env.out_position in
Array.iter (out_label_with_orig env org) lbl_bodies
| Kclosurecofix(nfv,init,lbl_types,lbl_bodies) ->
out env opCLOSURECOFIX;out_int env (Array.length lbl_bodies);
out_int env nfv; out_int env init; let org = env.out_position in
Array.iter (out_label_with_orig env org) lbl_types; let org = env.out_position in
Array.iter (out_label_with_orig env org) lbl_bodies
| Kgetglobal q ->
out env opGETGLOBAL; slot_for_getglobal env q
| Ksubstinstance u ->
out env opSUBSTINSTANCE; slot_for_const env (Const_univ_instance u)
| Kconst (Const_b0 i) when is_immed i -> if i >= 0 && i <= 3 then out env (opCONST0 + i) else (out env opCONSTINT; out_int env i)
| Kconst c ->
out env opGETGLOBAL; slot_for_const env c
| Kmakeblock(n, t) -> if 0 < n && n < 4 then (out env(opMAKEBLOCK1 + n - 1); out_int env t) else (out env opMAKEBLOCK; out_int env n; out_int env t)
| Kmakeswitchblock(typlbl,swlbl,annot,sz) ->
out env opMAKESWITCHBLOCK;
out_label env typlbl; out_label env swlbl;
slot_for_annot env annot;out_int env sz
| Kswitch (tbl_const, tbl_block) -> let lenb = Array.length tbl_block in let lenc = Array.length tbl_const in
assert (lenb < 0x100 && lenc < 0x1000000);
out env opSWITCH;
out_word env lenb lenc (lenc asr 8) (lenc asr 16); (* out_int env (Array.length tbl_const + (Array.length tbl_block lsl 23)); *) let org = env.out_position in
Array.iter (out_label_with_orig env org) tbl_const;
Array.iter (out_label_with_orig env org) tbl_block
| Kpushfields n ->
out env opPUSHFIELDS;out_int env n
| Kfield n -> if n <= 1 then out env (opGETFIELD0+n) else (out env opGETFIELD;out_int env n)
| Ksetfield n ->
out env opSETFIELD; out_int env n
| Ksequence _ -> invalid_arg "Vmemitcodes.emit_instr"
| Kproj p -> out env opPROJ; out_int env p
| Kensurestackcapacity size -> out env opENSURESTACKCAPACITY; out_int env size
| Kbranch lbl -> out env opBRANCH; out_label env lbl
| Kprim (op, (q,_u)) ->
out env (check_prim_op op);
slot_for_getglobal env q
| Kcamlprim (op,lbl) ->
out env (check_caml_prim_op op);
out_label env lbl;
slot_for_caml_prim env op
| Kstop -> out env opSTOP
(* Emission of a current list and remaining lists of instructions. Include some peephole optimization. *)
let rec emit env insns remaining = match insns with
| [] ->
(match remaining with
[] -> ()
| (first::rest) -> emit env first rest) (* Peephole optimizations *)
| Kpush :: Kacc n :: c -> let rec aux n c nb = match c with
| Kpush :: Kacc j :: c when j = n -> aux n c (nb + 1)
| _ -> (nb, c) in let (nb, c') = aux n c 1 in if nb >= 3 || (nb >= 2 && n > 7) then (
out env opPUSHACCMANY; out_int env n; out_int env nb;
emit env c' remaining) else ( if n = 0 then out env opPUSH elseif n < 8 then out env (opPUSHACC1 + n - 1) else (out env opPUSHACC; out_int env n);
emit env c remaining)
| Kpush :: Kenvacc n :: c -> let rec aux n c nb = match c with
| Kpush :: Kenvacc j :: c when j = n - nb -> aux n c (nb + 1)
| _ -> (nb, c) in let (nb, c') = aux n c 1 in if nb >= 3 || (nb >= 2 && n > 3) then (
out env opPUSHENVACCMANY; out_int env (n - nb + 1); out_int env nb;
emit env c' remaining) else ( if n >= 0 && n <= 3 then out env (opPUSHENVACC0 + n) else (out env opPUSHENVACC; out_int env n);
emit env c remaining)
| Kpush :: Koffsetclosure ofs :: c -> if Int.equal ofs 0 || Int.equal ofs 1 then out env(opPUSHOFFSETCLOSURE0 + ofs) else (out env opPUSHOFFSETCLOSURE; out_int env ofs);
emit env c remaining
| Kpush :: Kgetglobal id :: c ->
out env opPUSHGETGLOBAL; slot_for_getglobal env id; emit env c remaining
| Kpush :: Kconst (Const_b0 i) :: c when is_immed i -> if i >= 0 && i <= 3 then out env (opPUSHCONST0 + i) else (out env opPUSHCONSTINT; out_int env i);
emit env c remaining
| Kpush :: Kconst const :: c ->
out env opPUSHGETGLOBAL; slot_for_const env const;
emit env c remaining
| Kpushfields 1 :: c when is_accu_dead c ->
out env opGETFIELD0;
emit env (Kpush :: c) remaining
| Kpop n :: Kjump :: c ->
out env opRETURN; out_int env n; emit env c remaining
| Ksequence c1 :: c ->
emit env c1 (c :: remaining)
| Kprim (op1, (q1, _)) :: Kprim (op2, (q2, _)) :: c when inplace_prim_op op2 ->
out env (check_prim_op op1);
slot_for_getglobal env q1;
out env (check_prim_op_inplace op2);
slot_for_getglobal env q2;
emit env c remaining (* Default case *)
| instr :: c ->
emit_instr env instr; emit env c remaining
(* Substitution *)
let subst_patches subst p = let infos = CArray.Smart.map (fun r -> Reloc.subst subst r) p.reloc_infos in
{ reloc_infos = infos }
type'a pbody_code =
| BCdefined ofbool array * 'a * patches
| BCalias of Names.Constant.t
| BCconstant
type body_code = to_patch pbody_code
let subst_body_code s = function
| BCdefined (m, x, tp) -> BCdefined (m, x, subst_patches s tp)
| BCalias cu -> BCalias (subst_constant s cu)
| BCconstant -> BCconstant
let to_memory fv code = let env = {
out_buffer = Bytes.create 1024;
out_position = 0;
reloc_id = 0;
reloc_pos = [];
label_table = Array.make 16 (Label_undefined []);
reloc_info = RelocTable.create 91;
} in
emit env code []; let code = compress_code env.out_buffer env.out_position in let _, code = CString.hcons code in let fold reloc id accu = (id, reloc) :: accu in let reloc = RelocTable.fold fold env.reloc_info [] in let reloc = List.sort (fun (id1, _) (id2, _) -> Int.compare id1 id2) reloc in let uid = ref 0 in let table = ref [] in let push r = let id = !uid in let () = table := r :: !table in let () = incr uid in
Reloc.SReloc_indirect id in letmap (_, r) = letopen NonSubstReloc in match r with
| Reloc_getglobal cst -> Reloc.SReloc_getglobal cst
| Reloc_const (Const_ind ind) -> Reloc.SReloc_Const_ind ind
| Reloc_annot annot -> push (SReloc_annot annot)
| Reloc_caml_prim prm -> push (SReloc_caml_prim prm)
| Reloc_const (Const_sort s) -> push (SReloc_Const_sort s)
| Reloc_const (Const_evar e) -> push (SReloc_Const_evar e)
| Reloc_const (Const_b0 tag) -> push (SReloc_Const_b0 tag)
| Reloc_const (Const_univ_instance u) -> push (SReloc_Const_univ_instance u)
| Reloc_const (Const_val v) -> push (SReloc_Const_val v)
| Reloc_const (Const_uint i) -> push (SReloc_Const_uint i)
| Reloc_const (Const_float f) -> push (SReloc_Const_float f)
| Reloc_const (Const_string s) -> push (SReloc_Const_string s) in let reloc_infos = CArray.map_of_list map reloc in let positions = Positions.of_list (List.rev env.reloc_pos) in let reloc = { reloc_infos } in let to_patch = {
tp_code = code;
tp_fv = fv;
tp_pos = positions;
tp_reloc = CArray.rev_of_list !table;
} in
Array.iter (fun lbl ->
(match lbl with
Label_defined _ -> assert true
| Label_undefined patchlist ->
assert (patchlist = []))) env.label_table;
(to_patch, reloc)
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