gcc/data-streamer-in.c

   1 /* Routines for restoring various data types from a file stream.  This deals
   2    with various data types like strings, integers, enums, etc.
   3
   4    Copyright 2011 Free Software Foundation, Inc.
   5    Contributed by Diego Novillo <dnovillo@google.com>
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 3, or (at your option) any later
  12 version.
  13
  14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17 for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "diagnostic.h"
  27 #include "data-streamer.h"
  28
  29 /* Read a string from the string table in DATA_IN using input block
  30    IB.  Write the length to RLEN.  */
  31
  32 const char *
  33 string_for_index (struct data_in *data_in, unsigned int loc, unsigned int *rlen)
  34 {
  35   struct lto_input_block str_tab;
  36   unsigned int len;
  37   const char *result;
  38
  39   if (!loc)
  40     {
  41       *rlen = 0;
  42       return NULL;
  43     }
  44
  45   /* Get the string stored at location LOC in DATA_IN->STRINGS.  */
  46   LTO_INIT_INPUT_BLOCK (str_tab, data_in->strings, loc - 1,
  47                         data_in->strings_len);
  48   len = streamer_read_uhwi (&str_tab);
  49   *rlen = len;
  50
  51   if (str_tab.p + len > data_in->strings_len)
  52     internal_error ("bytecode stream: string too long for the string table");
  53
  54   result = (const char *)(data_in->strings + str_tab.p);
  55
  56   return result;
  57 }
  58
  59
  60 /* Read a string from the string table in DATA_IN using input block
  61    IB.  Write the length to RLEN.  */
  62
  63 const char *
  64 streamer_read_indexed_string (struct data_in *data_in,
  65                               struct lto_input_block *ib, unsigned int *rlen)
  66 {
  67   return string_for_index (data_in, streamer_read_uhwi (ib), rlen);
  68 }
  69
  70
  71 /* Read a NULL terminated string from the string table in DATA_IN.  */
  72
  73 const char *
  74 streamer_read_string (struct data_in *data_in, struct lto_input_block *ib)
  75 {
  76   unsigned int len;
  77   const char *ptr;
  78
  79   ptr = streamer_read_indexed_string (data_in, ib, &len);
  80   if (!ptr)
  81     return NULL;
  82   if (ptr[len - 1] != '\0')
  83     internal_error ("bytecode stream: found non-null terminated string");
  84
  85   return ptr;
  86 }
  87
  88
  89 /* Read a string from the string table in DATA_IN using the bitpack BP.
  90    Write the length to RLEN.  */
  91
  92 const char *
  93 bp_unpack_indexed_string (struct data_in *data_in,
  94                           struct bitpack_d *bp, unsigned int *rlen)
  95 {
  96   return string_for_index (data_in, bp_unpack_var_len_unsigned (bp), rlen);
  97 }
  98
  99
 100 /* Read a NULL terminated string from the string table in DATA_IN.  */
 101
 102 const char *
 103 bp_unpack_string (struct data_in *data_in, struct bitpack_d *bp)
 104 {
 105   unsigned int len;
 106   const char *ptr;
 107
 108   ptr = bp_unpack_indexed_string (data_in, bp, &len);
 109   if (!ptr)
 110     return NULL;
 111   if (ptr[len - 1] != '\0')
 112     internal_error ("bytecode stream: found non-null terminated string");
 113
 114   return ptr;
 115 }
 116
 117
 118 /* Read an unsigned HOST_WIDE_INT number from IB.  */
 119
 120 unsigned HOST_WIDE_INT
 121 streamer_read_uhwi (struct lto_input_block *ib)
 122 {
 123   unsigned HOST_WIDE_INT result = 0;
 124   int shift = 0;
 125   unsigned HOST_WIDE_INT byte;
 126
 127   while (true)
 128     {
 129       byte = streamer_read_uchar (ib);
 130       result |= (byte & 0x7f) << shift;
 131       shift += 7;
 132       if ((byte & 0x80) == 0)
 133         return result;
 134     }
 135 }
 136
 137
 138 /* Read a HOST_WIDE_INT number from IB.  */
 139
 140 HOST_WIDE_INT
 141 streamer_read_hwi (struct lto_input_block *ib)
 142 {
 143   HOST_WIDE_INT result = 0;
 144   int shift = 0;
 145   unsigned HOST_WIDE_INT byte;
 146
 147   while (true)
 148     {
 149       byte = streamer_read_uchar (ib);
 150       result |= (byte & 0x7f) << shift;
 151       shift += 7;
 152       if ((byte & 0x80) == 0)
 153         {
 154           if ((shift < HOST_BITS_PER_WIDE_INT) && (byte & 0x40))
 155             result |= - ((HOST_WIDE_INT)1 << shift);
 156
 157           return result;
 158         }
 159     }
 160 }