Source file memory_manager.ml
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exception Non_mergeable = Types.Non_mergeable
open Sexpr
module type CONTEXT = sig
include Ai.S
val anchor : t -> Memory.t -> unit
val anchored : t -> Memory.t -> bool
end
module Make (D : Domains.S) (C : CONTEXT with type v := D.t) : sig
include module type of Memory
val source : C.t -> addr:Expr.t -> len:int -> Loader_buf.t -> t -> t
val write : C.t -> addr:Expr.t -> Expr.t -> Expr.endianness -> t -> t
val read : C.t -> addr:Expr.t -> int -> Expr.endianness -> t -> Expr.t
val merge : C.t -> Expr.t -> t -> t -> t
end = struct
include Memory
let rebase (addr : Expr.t) =
match addr with
| Cst bv -> (Expr.zeros (Bv.size_of bv), bv)
| Binary { f = Plus; x; y = Cst bv; _ } -> (x, bv)
| Binary { f = Minus; x; y = Cst bv; _ } -> (x, Bv.neg bv)
| _ -> (addr, Bv.zeros (Expr.sizeof addr))
let blit offset buf len over =
let s = Bigarray.Array1.dim buf in
if len <= s then
let buf = Bigarray.Array1.sub buf 0 len in
Store.store offset (Chunk.of_hunk buf) over
else
let buf' =
Bigarray.Array1.create Bigarray.int8_unsigned Bigarray.C_layout (len - s)
in
Bigarray.Array1.fill buf' 0;
if s = 0 then Store.store offset (Chunk.of_hunk buf') over
else
Store.store (Bv.add_int offset s) (Chunk.of_hunk buf')
(Store.store offset (Chunk.of_hunk buf) over)
let fill addr len orig over =
let addr, offset = rebase addr in
layer addr (blit offset orig len Store.empty) over
let source ctx ~addr ~len orig over =
match over with
| Root | Symbol _ -> fill addr len orig over
| Layer _ when C.anchored ctx over -> fill addr len orig over
| Layer { addr = addr'; store = store'; over = over'; _ } -> (
match Expr.sub addr addr' with
| Expr.Cst bv -> layer addr' (blit bv orig len store') over'
| _ ->
C.anchor ctx over;
fill addr len orig over)
let singleton addr value over =
let addr, offset = rebase addr in
layer addr (Store.singleton offset (Chunk.of_term value)) over
let write env ~addr value (dir : Expr.endianness) over =
let value =
match dir with LittleEndian -> value | BigEndian -> bswap value
in
match over with
| Root | Symbol _ -> singleton addr value over
| Layer _ when C.anchored env over -> singleton addr value over
| Layer { addr = addr'; store = store'; over = over'; _ } -> (
match Expr.sub addr addr' with
| Expr.Cst bv ->
layer addr' (Store.store bv (Chunk.of_term value) store') over'
| _ ->
C.anchor env over;
singleton addr value over)
let rec read env ~addr bytes (dir : Expr.endianness) memory =
match memory with
| Root | Symbol _ -> Expr.load bytes dir addr memory
| Layer { addr = addr'; store; over; _ } -> (
match Expr.sub addr addr' with
| Expr.Cst bv -> (
let miss i s =
Chunk.of_term
(read env ~addr:(Expr.addz addr' i) s Expr.LittleEndian over)
in
let bytes = Chunk.to_term (Store.select miss bv bytes store) in
match dir with LittleEndian -> bytes | BigEndian -> bswap bytes)
| e -> (
let d = C.eval env e and size = Expr.sizeof e in
match D.project ~size d with
| Point z -> (
let miss i s =
Chunk.of_term
(read env ~addr:(Expr.addz addr' i) s Expr.LittleEndian over)
in
let bv = Bv.create z size in
let bytes = Chunk.to_term (Store.select miss bv bytes store) in
match dir with
| LittleEndian -> bytes
| BigEndian -> bswap bytes)
| Seq { start; n } ->
let last = Z.add (Z.add start n) (Z.of_int (bytes - 2))
and size = Expr.sizeof e in
if
if Z.numbits last > size then
Store.is_empty_between start
(Z.extract Z.minus_one 0 size)
store
&& Store.is_empty_between Z.zero (Z.extract last 0 size)
store
else Store.is_empty_between start last store
then read env ~addr bytes dir over
else (
if not (C.anchored env memory) then C.anchor env memory;
Expr.load bytes dir addr memory)
| Top ->
if not (C.anchored env memory) then C.anchor env memory;
Expr.load bytes dir addr memory))
let rec merge env c t t' =
if t == t' then t
else
match (t, t') with
| Layer { over; addr; store; _ }, t'
when over == t' && not (C.anchored env t) ->
let store =
Store.map
(fun offset chunk ->
if not (Chunk.is_hunk chunk) then
let value = Chunk.to_term chunk in
let size = Expr.sizeof value in
Chunk.of_term
(Expr.ite c value
(read env ~addr:(Expr.addz addr offset) (size / 8)
LittleEndian over))
else raise_notrace Non_mergeable)
store
in
layer addr store over
| t, Layer { over; _ } when t == over -> merge env (Expr.lognot c) t' t
| ( Layer { over; addr; store; _ },
Layer { over = over'; addr = addr'; store = store'; _ } )
when Expr.is_equal addr addr' && over == over'
&& (not (C.anchored env t))
&& not (C.anchored env t') ->
let store =
Store.merge
(fun offset o0 o1 ->
match (o0, o1) with
| Some c0, Some c1 ->
if Chunk.equal c0 c1 then o0
else
Some
(Chunk.of_term
(Expr.ite c (Chunk.to_term c0) (Chunk.to_term c1)))
| Some c0, None ->
let value = Chunk.to_term c0 in
let size = Expr.sizeof value in
Some
(Chunk.of_term
(Expr.ite c value
(read env ~addr:(Expr.addz addr offset) (size / 8)
LittleEndian over)))
| None, Some c1 ->
let value = Chunk.to_term c1 in
let size = Expr.sizeof value in
Some
(Chunk.of_term
(Expr.ite c
(read env ~addr:(Expr.addz addr offset) (size / 8)
LittleEndian over)
value))
| None, None -> None)
store store'
in
layer addr store over
| (Root | Symbol _ | Layer _), (Root | Symbol _ | Layer _) ->
raise_notrace Non_mergeable
end