gcc/data-streamer.c

   1 /* Generic streaming support for basic data types.
   2
   3    Copyright (C) 2011-2013 Free Software Foundation, Inc.
   4    Contributed by Diego Novillo <dnovillo@google.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tree.h"
  26 #include "gimple.h"
  27 #include "data-streamer.h"
  28
  29 /* Pack WORK into BP in a variant of uleb format.  */
  30
  31 void
  32 bp_pack_var_len_unsigned (struct bitpack_d *bp, unsigned HOST_WIDE_INT work)
  33 {
  34   do
  35     {
  36       unsigned int half_byte = (work & 0x7);
  37       work >>= 3;
  38       if (work != 0)
  39         /* More half_bytes to follow.  */
  40         half_byte |= 0x8;
  41
  42       bp_pack_value (bp, half_byte, 4);
  43     }
  44   while (work != 0);
  45 }
  46
  47
  48 /* Pack WORK into BP in a variant of sleb format.  */
  49
  50 void
  51 bp_pack_var_len_int (struct bitpack_d *bp, HOST_WIDE_INT work)
  52 {
  53   int more, half_byte;
  54
  55   do
  56     {
  57       half_byte = (work & 0x7);
  58       /* arithmetic shift */
  59       work >>= 3;
  60       more = !((work == 0 && (half_byte & 0x4) == 0)
  61                || (work == -1 && (half_byte & 0x4) != 0));
  62       if (more)
  63         half_byte |= 0x8;
  64
  65       bp_pack_value (bp, half_byte, 4);
  66     }
  67   while (more);
  68 }
  69
  70
  71 /* Unpack VAL from BP in a variant of uleb format.  */
  72
  73 unsigned HOST_WIDE_INT
  74 bp_unpack_var_len_unsigned (struct bitpack_d *bp)
  75 {
  76   unsigned HOST_WIDE_INT result = 0;
  77   int shift = 0;
  78   unsigned HOST_WIDE_INT half_byte;
  79
  80   while (true)
  81     {
  82       half_byte = bp_unpack_value (bp, 4);
  83       result |= (half_byte & 0x7) << shift;
  84       shift += 3;
  85       if ((half_byte & 0x8) == 0)
  86         return result;
  87     }
  88 }
  89
  90
  91 /* Unpack VAL from BP in a variant of sleb format.  */
  92
  93 HOST_WIDE_INT
  94 bp_unpack_var_len_int (struct bitpack_d *bp)
  95 {
  96   HOST_WIDE_INT result = 0;
  97   int shift = 0;
  98   unsigned HOST_WIDE_INT half_byte;
  99
 100   while (true)
 101     {
 102       half_byte = bp_unpack_value (bp, 4);
 103       result |= (half_byte & 0x7) << shift;
 104       shift += 3;
 105       if ((half_byte & 0x8) == 0)
 106         {
 107           if ((shift < HOST_BITS_PER_WIDE_INT) && (half_byte & 0x4))
 108             result |= - ((HOST_WIDE_INT)1 << shift);
 109
 110           return result;
 111         }
 112     }
 113 }