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 (C) 2011-2014 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 "tree.h"
  28 #include "basic-block.h"
  29 #include "tree-ssa-alias.h"
  30 #include "internal-fn.h"
  31 #include "gimple-expr.h"
  32 #include "is-a.h"
  33 #include "gimple.h"
  34 #include "data-streamer.h"
  35
  36 /* Read a string from the string table in DATA_IN using input block
  37    IB.  Write the length to RLEN.  */
  38
  39 static const char *
  40 string_for_index (struct data_in *data_in, unsigned int loc, unsigned int *rlen)
  41 {
  42   unsigned int len;
  43   const char *result;
  44
  45   if (!loc)
  46     {
  47       *rlen = 0;
  48       return NULL;
  49     }
  50
  51   /* Get the string stored at location LOC in DATA_IN->STRINGS.  */
  52   lto_input_block str_tab (data_in->strings, loc - 1, data_in->strings_len);
  53   len = streamer_read_uhwi (&str_tab);
  54   *rlen = len;
  55
  56   if (str_tab.p + len > data_in->strings_len)
  57     internal_error ("bytecode stream: string too long for the string table");
  58
  59   result = (const char *)(data_in->strings + str_tab.p);
  60
  61   return result;
  62 }
  63
  64
  65 /* Read a string from the string table in DATA_IN using input block
  66    IB.  Write the length to RLEN.  */
  67
  68 const char *
  69 streamer_read_indexed_string (struct data_in *data_in,
  70                               struct lto_input_block *ib, unsigned int *rlen)
  71 {
  72   return string_for_index (data_in, streamer_read_uhwi (ib), rlen);
  73 }
  74
  75
  76 /* Read a NULL terminated string from the string table in DATA_IN.  */
  77
  78 const char *
  79 streamer_read_string (struct data_in *data_in, struct lto_input_block *ib)
  80 {
  81   unsigned int len;
  82   const char *ptr;
  83
  84   ptr = streamer_read_indexed_string (data_in, ib, &len);
  85   if (!ptr)
  86     return NULL;
  87   if (ptr[len - 1] != '\0')
  88     internal_error ("bytecode stream: found non-null terminated string");
  89
  90   return ptr;
  91 }
  92
  93
  94 /* Read a string from the string table in DATA_IN using the bitpack BP.
  95    Write the length to RLEN.  */
  96
  97 const char *
  98 bp_unpack_indexed_string (struct data_in *data_in,
  99                           struct bitpack_d *bp, unsigned int *rlen)
 100 {
 101   return string_for_index (data_in, bp_unpack_var_len_unsigned (bp), rlen);
 102 }
 103
 104
 105 /* Read a NULL terminated string from the string table in DATA_IN.  */
 106
 107 const char *
 108 bp_unpack_string (struct data_in *data_in, struct bitpack_d *bp)
 109 {
 110   unsigned int len;
 111   const char *ptr;
 112
 113   ptr = bp_unpack_indexed_string (data_in, bp, &len);
 114   if (!ptr)
 115     return NULL;
 116   if (ptr[len - 1] != '\0')
 117     internal_error ("bytecode stream: found non-null terminated string");
 118
 119   return ptr;
 120 }
 121
 122
 123 /* Read an unsigned HOST_WIDE_INT number from IB.  */
 124
 125 unsigned HOST_WIDE_INT
 126 streamer_read_uhwi (struct lto_input_block *ib)
 127 {
 128   unsigned HOST_WIDE_INT result;
 129   int shift;
 130   unsigned HOST_WIDE_INT byte;
 131   unsigned int p = ib->p;
 132   unsigned int len = ib->len;
 133
 134   const char *data = ib->data;
 135   result = data[p++];
 136   if ((result & 0x80) != 0)
 137     {
 138       result &= 0x7f;
 139       shift = 7;
 140       do
 141         {
 142           byte = data[p++];
 143           result |= (byte & 0x7f) << shift;
 144           shift += 7;
 145         }
 146       while ((byte & 0x80) != 0);
 147     }
 148
 149   /* We check for section overrun after the fact for performance reason.  */
 150   if (p > len)
 151     lto_section_overrun (ib);
 152
 153   ib->p = p;
 154   return result;
 155 }
 156
 157
 158 /* Read a HOST_WIDE_INT number from IB.  */
 159
 160 HOST_WIDE_INT
 161 streamer_read_hwi (struct lto_input_block *ib)
 162 {
 163   HOST_WIDE_INT result = 0;
 164   int shift = 0;
 165   unsigned HOST_WIDE_INT byte;
 166
 167   while (true)
 168     {
 169       byte = streamer_read_uchar (ib);
 170       result |= (byte & 0x7f) << shift;
 171       shift += 7;
 172       if ((byte & 0x80) == 0)
 173         {
 174           if ((shift < HOST_BITS_PER_WIDE_INT) && (byte & 0x40))
 175             result |= - (HOST_WIDE_INT_1U << shift);
 176
 177           return result;
 178         }
 179     }
 180 }
 181
 182 /* Read gcov_type value from IB.  */
 183
 184 gcov_type
 185 streamer_read_gcov_count (struct lto_input_block *ib)
 186 {
 187   gcov_type ret = streamer_read_hwi (ib);
 188   gcc_assert (ret >= 0);
 189   return ret;
 190 }