gcc/data-streamer.c

   1 /* Generic streaming support for basic data types.
   2
   3    Copyright (C) 2011-2017 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 "backend.h"
  26 #include "tree.h"
  27 #include "gimple.h"
  28 #include "cgraph.h"
  29 #include "data-streamer.h"
  30
  31 /* Pack WORK into BP in a variant of uleb format.  */
  32
  33 void
  34 bp_pack_var_len_unsigned (struct bitpack_d *bp, unsigned HOST_WIDE_INT work)
  35 {
  36   do
  37     {
  38       unsigned int half_byte = (work & 0x7);
  39       work >>= 3;
  40       if (work != 0)
  41         /* More half_bytes to follow.  */
  42         half_byte |= 0x8;
  43
  44       bp_pack_value (bp, half_byte, 4);
  45     }
  46   while (work != 0);
  47 }
  48
  49
  50 /* Pack WORK into BP in a variant of sleb format.  */
  51
  52 void
  53 bp_pack_var_len_int (struct bitpack_d *bp, HOST_WIDE_INT work)
  54 {
  55   int more, half_byte;
  56
  57   do
  58     {
  59       half_byte = (work & 0x7);
  60       /* arithmetic shift */
  61       work >>= 3;
  62       more = !((work == 0 && (half_byte & 0x4) == 0)
  63                || (work == -1 && (half_byte & 0x4) != 0));
  64       if (more)
  65         half_byte |= 0x8;
  66
  67       bp_pack_value (bp, half_byte, 4);
  68     }
  69   while (more);
  70 }
  71
  72
  73 /* Unpack VAL from BP in a variant of uleb format.  */
  74
  75 unsigned HOST_WIDE_INT
  76 bp_unpack_var_len_unsigned (struct bitpack_d *bp)
  77 {
  78   unsigned HOST_WIDE_INT result = 0;
  79   int shift = 0;
  80   unsigned HOST_WIDE_INT half_byte;
  81
  82   while (true)
  83     {
  84       half_byte = bp_unpack_value (bp, 4);
  85       result |= (half_byte & 0x7) << shift;
  86       shift += 3;
  87       if ((half_byte & 0x8) == 0)
  88         return result;
  89     }
  90 }
  91
  92
  93 /* Unpack VAL from BP in a variant of sleb format.  */
  94
  95 HOST_WIDE_INT
  96 bp_unpack_var_len_int (struct bitpack_d *bp)
  97 {
  98   HOST_WIDE_INT result = 0;
  99   int shift = 0;
 100   unsigned HOST_WIDE_INT half_byte;
 101
 102   while (true)
 103     {
 104       half_byte = bp_unpack_value (bp, 4);
 105       result |= (half_byte & 0x7) << shift;
 106       shift += 3;
 107       if ((half_byte & 0x8) == 0)
 108         {
 109           if ((shift < HOST_BITS_PER_WIDE_INT) && (half_byte & 0x4))
 110             result |= - (HOST_WIDE_INT_1U << shift);
 111
 112           return result;
 113         }
 114     }
 115 }