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