diff options
Diffstat (limited to 'cparser/Cutil.ml')
| -rw-r--r-- | cparser/Cutil.ml | 103 |
1 files changed, 47 insertions, 56 deletions
diff --git a/cparser/Cutil.ml b/cparser/Cutil.ml index 3467c092..d3a830ce 100644 --- a/cparser/Cutil.ml +++ b/cparser/Cutil.ml @@ -6,10 +6,11 @@ (* *) (* Copyright Institut National de Recherche en Informatique et en *) (* Automatique. All rights reserved. This file is distributed *) -(* under the terms of the GNU General Public License as published by *) -(* the Free Software Foundation, either version 2 of the License, or *) -(* (at your option) any later version. This file is also distributed *) -(* under the terms of the INRIA Non-Commercial License Agreement. *) +(* under the terms of the GNU Lesser General Public License as *) +(* published by the Free Software Foundation, either version 2.1 of *) +(* the License, or (at your option) any later version. *) +(* This file is also distributed under the terms of the *) +(* INRIA Non-Commercial License Agreement. *) (* *) (* *********************************************************************) @@ -448,34 +449,6 @@ let rec equal_types env t1 t2 = let compatible_types mode env t1 t2 = match combine_types mode env t1 t2 with Some _ -> true | None -> false -(* Naive placement algorithm for bit fields, might not match that - of the compiler. *) - -let pack_bitfields ml = - let rec pack nbits = function - | [] -> - (nbits, []) - | m :: ms as ml -> - match m.fld_bitfield with - | None -> (nbits, ml) - | Some n -> - if n = 0 then - (nbits, ms) (* bit width 0 means end of pack *) - else if nbits + n > 8 * !config.sizeof_int then - (nbits, ml) (* doesn't fit in current word *) - else - pack (nbits + n) ms (* add to current word *) - in - let (nbits, ml') = pack 0 ml in - let (sz, al) = - (* A lone bitfield of width 0 consumes no space and aligns to 1 *) - if nbits = 0 then (0, 1) else - if nbits <= 8 then (1, 1) else - if nbits <= 16 then (2, 2) else - if nbits <= 32 then (4, 4) else - if nbits <= 64 then (8, 8) else assert false in - (sz, al, ml') - (* Natural alignment, in bytes *) let alignof_ikind = function @@ -519,15 +492,13 @@ let rec alignof env t = let alignof_struct_union env members = let rec align_rec al = function | [] -> Some al - | m :: rem as ml -> - if m.fld_bitfield = None then begin + | m :: rem -> + if m.fld_name = "" then + align_rec al rem + else match alignof env m.fld_typ with | None -> None | Some a -> align_rec (max a al) rem - end else begin - let (s, a, ml') = pack_bitfields ml in - align_rec (max a al) ml' - end in align_rec 1 members let align x boundary = @@ -604,43 +575,63 @@ let sizeof_union env members = Bitfields are taken into account for the size and offset computations but not given an offset. Not done here but in composite_info_def: rounding size to alignment. *) + let sizeof_layout_struct env members ma = - let align_offset ofs a = - align ofs (if ma > 0 && a > ma then ma else a) in - let rec sizeof_rec ofs accu = function + + let align_bit_offset pos a = + align pos (8 * (if ma > 0 && a > ma then ma else a)) in + + let record_field name pos = + assert (pos mod 8 = 0); + (name, pos / 8) in + + (* pos is the current position in bits *) + let rec sizeof_rec pos accu = function | [] -> - Some (ofs, accu) + Some (pos, accu) | [ { fld_typ = TArray(_, None, _) } as m ] -> (* C99: ty[] allowed as last field *) begin match alignof env m.fld_typ with | Some a -> - let ofs = align_offset ofs a in - Some (ofs, (m.fld_name, ofs) :: accu) + let pos = align_bit_offset pos a in + Some (pos, record_field m.fld_name pos :: accu) | None -> None end - | m :: rem as ml -> - if m.fld_bitfield = None then begin - match alignof env m.fld_typ, sizeof env m.fld_typ with - | Some a, Some s -> - let ofs = align_offset ofs a in - sizeof_rec (ofs + s) ((m.fld_name, ofs) :: accu) rem - | _, _ -> None - end else begin - let (s, a, ml') = pack_bitfields ml in - sizeof_rec (align_offset ofs a + s) accu ml' + | m :: rem -> + begin match alignof env m.fld_typ, sizeof env m.fld_typ with + | Some a, Some s -> + begin match m.fld_bitfield with + | None -> + let pos = align_bit_offset pos a in + sizeof_rec (pos + s * 8) + (record_field m.fld_name pos :: accu) + rem + | Some width -> + (* curr = beginning of storage unit, in bits + next = one past end of storage unit, in bits *) + let curr = pos / (a * 8) * (a * 8) in + let next = curr + s * 8 in + let pos' = + if width <= 0 then align pos (a * 8) + else if pos + width <= next then pos + width + else next + width in + sizeof_rec pos' accu rem + end + | _, _ -> + None end in sizeof_rec 0 [] members let sizeof_struct env members ma = match sizeof_layout_struct env members ma with | None -> None - | Some(sz, offsets) -> Some sz + | Some(bitsize, offsets) -> Some ((bitsize + 7) / 8) (* Compute the offsets of all non-bitfield members of a struct. *) let struct_layout env attrs members = let (ma, _, _) = packing_parameters attrs in match sizeof_layout_struct env members ma with - | Some(sz, offsets) -> offsets + | Some(bitsize, offsets) -> offsets | None -> [] (* Compute the offset of a struct member *) |