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) 2011-2015 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 "input.h"
  28 #include "alias.h"
  29 #include "symtab.h"
  30 #include "options.h"
  31 #include "tree.h"
  32 #include "fold-const.h"
  33 #include "predict.h"
  34 #include "tm.h"
  35 #include "hard-reg-set.h"
  36 #include "input.h"
  37 #include "function.h"
  38 #include "basic-block.h"
  39 #include "tree-ssa-alias.h"
  40 #include "internal-fn.h"
  41 #include "gimple-expr.h"
  42 #include "is-a.h"
  43 #include "gimple.h"
  44 #include "plugin-api.h"
  45 #include "ipa-ref.h"
  46 #include "cgraph.h"
  47 #include "data-streamer.h"
  48
  49 /* Read a string from the string table in DATA_IN using input block
  50    IB.  Write the length to RLEN.  */
  51
  52 static const char *
  53 string_for_index (struct data_in *data_in, unsigned int loc, unsigned int *rlen)
  54 {
  55   unsigned int len;
  56   const char *result;
  57
  58   if (!loc)
  59     {
  60       *rlen = 0;
  61       return NULL;
  62     }
  63
  64   /* Get the string stored at location LOC in DATA_IN->STRINGS.  */
  65   lto_input_block str_tab (data_in->strings, loc - 1, data_in->strings_len, NULL);
  66   len = streamer_read_uhwi (&str_tab);
  67   *rlen = len;
  68
  69   if (str_tab.p + len > data_in->strings_len)
  70     internal_error ("bytecode stream: string too long for the string table");
  71
  72   result = (const char *)(data_in->strings + str_tab.p);
  73
  74   return result;
  75 }
  76
  77
  78 /* Read a string from the string table in DATA_IN using input block
  79    IB.  Write the length to RLEN.  */
  80
  81 const char *
  82 streamer_read_indexed_string (struct data_in *data_in,
  83                               struct lto_input_block *ib, unsigned int *rlen)
  84 {
  85   return string_for_index (data_in, streamer_read_uhwi (ib), rlen);
  86 }
  87
  88
  89 /* Read a NULL terminated string from the string table in DATA_IN.  */
  90
  91 const char *
  92 streamer_read_string (struct data_in *data_in, struct lto_input_block *ib)
  93 {
  94   unsigned int len;
  95   const char *ptr;
  96
  97   ptr = streamer_read_indexed_string (data_in, ib, &len);
  98   if (!ptr)
  99     return NULL;
 100   if (ptr[len - 1] != '\0')
 101     internal_error ("bytecode stream: found non-null terminated string");
 102
 103   return ptr;
 104 }
 105
 106
 107 /* Read a string from the string table in DATA_IN using the bitpack BP.
 108    Write the length to RLEN.  */
 109
 110 const char *
 111 bp_unpack_indexed_string (struct data_in *data_in,
 112                           struct bitpack_d *bp, unsigned int *rlen)
 113 {
 114   return string_for_index (data_in, bp_unpack_var_len_unsigned (bp), rlen);
 115 }
 116
 117
 118 /* Read a NULL terminated string from the string table in DATA_IN.  */
 119
 120 const char *
 121 bp_unpack_string (struct data_in *data_in, struct bitpack_d *bp)
 122 {
 123   unsigned int len;
 124   const char *ptr;
 125
 126   ptr = bp_unpack_indexed_string (data_in, bp, &len);
 127   if (!ptr)
 128     return NULL;
 129   if (ptr[len - 1] != '\0')
 130     internal_error ("bytecode stream: found non-null terminated string");
 131
 132   return ptr;
 133 }
 134
 135
 136 /* Read an unsigned HOST_WIDE_INT number from IB.  */
 137
 138 unsigned HOST_WIDE_INT
 139 streamer_read_uhwi (struct lto_input_block *ib)
 140 {
 141   unsigned HOST_WIDE_INT result;
 142   int shift;
 143   unsigned HOST_WIDE_INT byte;
 144   unsigned int p = ib->p;
 145   unsigned int len = ib->len;
 146
 147   const char *data = ib->data;
 148   result = data[p++];
 149   if ((result & 0x80) != 0)
 150     {
 151       result &= 0x7f;
 152       shift = 7;
 153       do
 154         {
 155           byte = data[p++];
 156           result |= (byte & 0x7f) << shift;
 157           shift += 7;
 158         }
 159       while ((byte & 0x80) != 0);
 160     }
 161
 162   /* We check for section overrun after the fact for performance reason.  */
 163   if (p > len)
 164     lto_section_overrun (ib);
 165
 166   ib->p = p;
 167   return result;
 168 }
 169
 170
 171 /* Read a HOST_WIDE_INT number from IB.  */
 172
 173 HOST_WIDE_INT
 174 streamer_read_hwi (struct lto_input_block *ib)
 175 {
 176   HOST_WIDE_INT result = 0;
 177   int shift = 0;
 178   unsigned HOST_WIDE_INT byte;
 179
 180   while (true)
 181     {
 182       byte = streamer_read_uchar (ib);
 183       result |= (byte & 0x7f) << shift;
 184       shift += 7;
 185       if ((byte & 0x80) == 0)
 186         {
 187           if ((shift < HOST_BITS_PER_WIDE_INT) && (byte & 0x40))
 188             result |= - (HOST_WIDE_INT_1U << shift);
 189
 190           return result;
 191         }
 192     }
 193 }
 194
 195 /* Read gcov_type value from IB.  */
 196
 197 gcov_type
 198 streamer_read_gcov_count (struct lto_input_block *ib)
 199 {
 200   gcov_type ret = streamer_read_hwi (ib);
 201   gcc_assert (ret >= 0);
 202   return ret;
 203 }