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) 2011-2016 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 "backend.h"
  27 #include "tree.h"
  28 #include "gimple.h"
  29 #include "cgraph.h"
  30 #include "data-streamer.h"
  31
  32 /* Read a string from the string table in DATA_IN using input block
  33    IB.  Write the length to RLEN.  */
  34
  35 static const char *
  36 string_for_index (struct data_in *data_in, unsigned int loc, unsigned int *rlen)
  37 {
  38   unsigned int len;
  39   const char *result;
  40
  41   if (!loc)
  42     {
  43       *rlen = 0;
  44       return NULL;
  45     }
  46
  47   /* Get the string stored at location LOC in DATA_IN->STRINGS.  */
  48   lto_input_block str_tab (data_in->strings, loc - 1, data_in->strings_len, NULL);
  49   len = streamer_read_uhwi (&str_tab);
  50   *rlen = len;
  51
  52   if (str_tab.p + len > data_in->strings_len)
  53     internal_error ("bytecode stream: string too long for the string table");
  54
  55   result = (const char *)(data_in->strings + str_tab.p);
  56
  57   return result;
  58 }
  59
  60
  61 /* Read a string from the string table in DATA_IN using input block
  62    IB.  Write the length to RLEN.  */
  63
  64 const char *
  65 streamer_read_indexed_string (struct data_in *data_in,
  66                               struct lto_input_block *ib, unsigned int *rlen)
  67 {
  68   return string_for_index (data_in, streamer_read_uhwi (ib), rlen);
  69 }
  70
  71
  72 /* Read a NULL terminated string from the string table in DATA_IN.  */
  73
  74 const char *
  75 streamer_read_string (struct data_in *data_in, struct lto_input_block *ib)
  76 {
  77   unsigned int len;
  78   const char *ptr;
  79
  80   ptr = streamer_read_indexed_string (data_in, ib, &len);
  81   if (!ptr)
  82     return NULL;
  83   if (ptr[len - 1] != '\0')
  84     internal_error ("bytecode stream: found non-null terminated string");
  85
  86   return ptr;
  87 }
  88
  89
  90 /* Read a string from the string table in DATA_IN using the bitpack BP.
  91    Write the length to RLEN.  */
  92
  93 const char *
  94 bp_unpack_indexed_string (struct data_in *data_in,
  95                           struct bitpack_d *bp, unsigned int *rlen)
  96 {
  97   return string_for_index (data_in, bp_unpack_var_len_unsigned (bp), rlen);
  98 }
  99
 100
 101 /* Read a NULL terminated string from the string table in DATA_IN.  */
 102
 103 const char *
 104 bp_unpack_string (struct data_in *data_in, struct bitpack_d *bp)
 105 {
 106   unsigned int len;
 107   const char *ptr;
 108
 109   ptr = bp_unpack_indexed_string (data_in, bp, &len);
 110   if (!ptr)
 111     return NULL;
 112   if (ptr[len - 1] != '\0')
 113     internal_error ("bytecode stream: found non-null terminated string");
 114
 115   return ptr;
 116 }
 117
 118
 119 /* Read an unsigned HOST_WIDE_INT number from IB.  */
 120
 121 unsigned HOST_WIDE_INT
 122 streamer_read_uhwi (struct lto_input_block *ib)
 123 {
 124   unsigned HOST_WIDE_INT result;
 125   int shift;
 126   unsigned HOST_WIDE_INT byte;
 127   unsigned int p = ib->p;
 128   unsigned int len = ib->len;
 129
 130   const char *data = ib->data;
 131   result = data[p++];
 132   if ((result & 0x80) != 0)
 133     {
 134       result &= 0x7f;
 135       shift = 7;
 136       do
 137         {
 138           byte = data[p++];
 139           result |= (byte & 0x7f) << shift;
 140           shift += 7;
 141         }
 142       while ((byte & 0x80) != 0);
 143     }
 144
 145   /* We check for section overrun after the fact for performance reason.  */
 146   if (p > len)
 147     lto_section_overrun (ib);
 148
 149   ib->p = p;
 150   return result;
 151 }
 152
 153
 154 /* Read a HOST_WIDE_INT number from IB.  */
 155
 156 HOST_WIDE_INT
 157 streamer_read_hwi (struct lto_input_block *ib)
 158 {
 159   HOST_WIDE_INT result = 0;
 160   int shift = 0;
 161   unsigned HOST_WIDE_INT byte;
 162
 163   while (true)
 164     {
 165       byte = streamer_read_uchar (ib);
 166       result |= (byte & 0x7f) << shift;
 167       shift += 7;
 168       if ((byte & 0x80) == 0)
 169         {
 170           if ((shift < HOST_BITS_PER_WIDE_INT) && (byte & 0x40))
 171             result |= - (HOST_WIDE_INT_1U << shift);
 172
 173           return result;
 174         }
 175     }
 176 }
 177
 178 /* Read gcov_type value from IB.  */
 179
 180 gcov_type
 181 streamer_read_gcov_count (struct lto_input_block *ib)
 182 {
 183   gcov_type ret = streamer_read_hwi (ib);
 184   gcc_assert (ret >= 0);
 185   return ret;
 186 }