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