gcc/data-streamer.c

   1 /* Generic streaming support for basic data types.
   2
   3    Copyright (C) 2011-2014 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 "basic-block.h"
  27 #include "tree-ssa-alias.h"
  28 #include "internal-fn.h"
  29 #include "gimple-expr.h"
  30 #include "is-a.h"
  31 #include "gimple.h"
  32 #include "data-streamer.h"
  33
  34 /* Pack WORK into BP in a variant of uleb format.  */
  35
  36 void
  37 bp_pack_var_len_unsigned (struct bitpack_d *bp, unsigned HOST_WIDE_INT work)
  38 {
  39   do
  40     {
  41       unsigned int half_byte = (work & 0x7);
  42       work >>= 3;
  43       if (work != 0)
  44         /* More half_bytes to follow.  */
  45         half_byte |= 0x8;
  46
  47       bp_pack_value (bp, half_byte, 4);
  48     }
  49   while (work != 0);
  50 }
  51
  52
  53 /* Pack WORK into BP in a variant of sleb format.  */
  54
  55 void
  56 bp_pack_var_len_int (struct bitpack_d *bp, HOST_WIDE_INT work)
  57 {
  58   int more, half_byte;
  59
  60   do
  61     {
  62       half_byte = (work & 0x7);
  63       /* arithmetic shift */
  64       work >>= 3;
  65       more = !((work == 0 && (half_byte & 0x4) == 0)
  66                || (work == -1 && (half_byte & 0x4) != 0));
  67       if (more)
  68         half_byte |= 0x8;
  69
  70       bp_pack_value (bp, half_byte, 4);
  71     }
  72   while (more);
  73 }
  74
  75
  76 /* Unpack VAL from BP in a variant of uleb format.  */
  77
  78 unsigned HOST_WIDE_INT
  79 bp_unpack_var_len_unsigned (struct bitpack_d *bp)
  80 {
  81   unsigned HOST_WIDE_INT result = 0;
  82   int shift = 0;
  83   unsigned HOST_WIDE_INT half_byte;
  84
  85   while (true)
  86     {
  87       half_byte = bp_unpack_value (bp, 4);
  88       result |= (half_byte & 0x7) << shift;
  89       shift += 3;
  90       if ((half_byte & 0x8) == 0)
  91         return result;
  92     }
  93 }
  94
  95
  96 /* Unpack VAL from BP in a variant of sleb format.  */
  97
  98 HOST_WIDE_INT
  99 bp_unpack_var_len_int (struct bitpack_d *bp)
 100 {
 101   HOST_WIDE_INT result = 0;
 102   int shift = 0;
 103   unsigned HOST_WIDE_INT half_byte;
 104
 105   while (true)
 106     {
 107       half_byte = bp_unpack_value (bp, 4);
 108       result |= (half_byte & 0x7) << shift;
 109       shift += 3;
 110       if ((half_byte & 0x8) == 0)
 111         {
 112           if ((shift < HOST_BITS_PER_WIDE_INT) && (half_byte & 0x4))
 113             result |= - ((HOST_WIDE_INT)1 << shift);
 114
 115           return result;
 116         }
 117     }
 118 }