gcc/data-streamer.h

   1 /* Generic streaming support for various data types.
   2
   3    Copyright (C) 2011-2015 Free Software Foundation, Inc.
   4    Contributed by Diego Novillo <dnovillo@google.com>
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #ifndef GCC_DATA_STREAMER_H
  23 #define GCC_DATA_STREAMER_H
  24
  25 #include "lto-streamer.h"
  26
  27 /* Data structures used to pack values and bitflags into a vector of
  28    words.  Used to stream values of a fixed number of bits in a space
  29    efficient way.  */
  30 static unsigned const BITS_PER_BITPACK_WORD = HOST_BITS_PER_WIDE_INT;
  31
  32 typedef unsigned HOST_WIDE_INT bitpack_word_t;
  33
  34 struct bitpack_d
  35 {
  36   /* The position of the first unused or unconsumed bit in the word.  */
  37   unsigned pos;
  38
  39   /* The current word we are (un)packing.  */
  40   bitpack_word_t word;
  41
  42   /* The lto_output_stream or the lto_input_block we are streaming to/from.  */
  43   void *stream;
  44 };
  45
  46 /* In data-streamer.c  */
  47 void bp_pack_var_len_unsigned (struct bitpack_d *, unsigned HOST_WIDE_INT);
  48 void bp_pack_var_len_int (struct bitpack_d *, HOST_WIDE_INT);
  49 unsigned HOST_WIDE_INT bp_unpack_var_len_unsigned (struct bitpack_d *);
  50 HOST_WIDE_INT bp_unpack_var_len_int (struct bitpack_d *);
  51
  52 /* In data-streamer-out.c  */
  53 void streamer_write_zero (struct output_block *);
  54 void streamer_write_uhwi (struct output_block *, unsigned HOST_WIDE_INT);
  55 void streamer_write_hwi (struct output_block *, HOST_WIDE_INT);
  56 void streamer_write_gcov_count (struct output_block *, gcov_type);
  57 void streamer_write_string (struct output_block *, struct lto_output_stream *,
  58                             const char *, bool);
  59 void streamer_write_string_with_length (struct output_block *,
  60                                         struct lto_output_stream *,
  61                                         const char *, unsigned int, bool);
  62 void bp_pack_string_with_length (struct output_block *, struct bitpack_d *,
  63                                  const char *, unsigned int, bool);
  64 void bp_pack_string (struct output_block *, struct bitpack_d *,
  65                      const char *, bool);
  66 void streamer_write_uhwi_stream (struct lto_output_stream *,
  67                                  unsigned HOST_WIDE_INT);
  68 void streamer_write_hwi_stream (struct lto_output_stream *, HOST_WIDE_INT);
  69 void streamer_write_gcov_count_stream (struct lto_output_stream *, gcov_type);
  70 void streamer_write_data_stream (struct lto_output_stream *, const void *,
  71                                  size_t);
  72
  73 /* In data-streamer-in.c  */
  74 const char *streamer_read_string (struct data_in *, struct lto_input_block *);
  75 const char *streamer_read_indexed_string (struct data_in *,
  76                                           struct lto_input_block *,
  77                                           unsigned int *);
  78 const char *bp_unpack_indexed_string (struct data_in *, struct bitpack_d *,
  79                                       unsigned int *);
  80 const char *bp_unpack_string (struct data_in *, struct bitpack_d *);
  81 unsigned HOST_WIDE_INT streamer_read_uhwi (struct lto_input_block *);
  82 HOST_WIDE_INT streamer_read_hwi (struct lto_input_block *);
  83 gcov_type streamer_read_gcov_count (struct lto_input_block *);
  84
  85 /* Returns a new bit-packing context for bit-packing into S.  */
  86 static inline struct bitpack_d
  87 bitpack_create (struct lto_output_stream *s)
  88 {
  89   struct bitpack_d bp;
  90   bp.pos = 0;
  91   bp.word = 0;
  92   bp.stream = (void *)s;
  93   return bp;
  94 }
  95
  96 /* Pack the NBITS bit sized value VAL into the bit-packing context BP.  */
  97 static inline void
  98 bp_pack_value (struct bitpack_d *bp, bitpack_word_t val, unsigned nbits)
  99 {
 100   bitpack_word_t word = bp->word;
 101   int pos = bp->pos;
 102
 103   /* Verify that VAL fits in the NBITS.  */
 104   gcc_checking_assert (nbits == BITS_PER_BITPACK_WORD
 105                        || !(val & ~(((bitpack_word_t)1<<nbits)-1)));
 106
 107   /* If val does not fit into the current bitpack word switch to the
 108      next one.  */
 109   if (pos + nbits > BITS_PER_BITPACK_WORD)
 110     {
 111       streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 112                                   word);
 113       word = val;
 114       pos = nbits;
 115     }
 116   else
 117     {
 118       word |= val << pos;
 119       pos += nbits;
 120     }
 121   bp->word = word;
 122   bp->pos = pos;
 123 }
 124
 125 /* Finishes bit-packing of BP.  */
 126 static inline void
 127 streamer_write_bitpack (struct bitpack_d *bp)
 128 {
 129   streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 130                               bp->word);
 131   bp->word = 0;
 132   bp->pos = 0;
 133 }
 134
 135 /* Returns a new bit-packing context for bit-unpacking from IB.  */
 136 static inline struct bitpack_d
 137 streamer_read_bitpack (struct lto_input_block *ib)
 138 {
 139   struct bitpack_d bp;
 140   bp.word = streamer_read_uhwi (ib);
 141   bp.pos = 0;
 142   bp.stream = (void *)ib;
 143   return bp;
 144 }
 145
 146 /* Unpacks NBITS bits from the bit-packing context BP and returns them.  */
 147 static inline bitpack_word_t
 148 bp_unpack_value (struct bitpack_d *bp, unsigned nbits)
 149 {
 150   bitpack_word_t mask, val;
 151   int pos = bp->pos;
 152
 153   mask = (nbits == BITS_PER_BITPACK_WORD
 154           ? (bitpack_word_t) -1
 155           : ((bitpack_word_t) 1 << nbits) - 1);
 156
 157   /* If there are not continuous nbits in the current bitpack word
 158      switch to the next one.  */
 159   if (pos + nbits > BITS_PER_BITPACK_WORD)
 160     {
 161       bp->word = val
 162         = streamer_read_uhwi ((struct lto_input_block *)bp->stream);
 163       bp->pos = nbits;
 164       return val & mask;
 165     }
 166   val = bp->word;
 167   val >>= pos;
 168   bp->pos = pos + nbits;
 169
 170   return val & mask;
 171 }
 172
 173
 174 /* Write a character to the output block.  */
 175
 176 static inline void
 177 streamer_write_char_stream (struct lto_output_stream *obs, char c)
 178 {
 179   /* No space left.  */
 180   if (obs->left_in_block == 0)
 181     lto_append_block (obs);
 182
 183   /* Write the actual character.  */
 184   char *current_pointer = obs->current_pointer;
 185   *(current_pointer++) = c;
 186   obs->current_pointer = current_pointer;
 187   obs->total_size++;
 188   obs->left_in_block--;
 189 }
 190
 191
 192 /* Read byte from the input block.  */
 193
 194 static inline unsigned char
 195 streamer_read_uchar (struct lto_input_block *ib)
 196 {
 197   if (ib->p >= ib->len)
 198     lto_section_overrun (ib);
 199   return (ib->data[ib->p++]);
 200 }
 201
 202 /* Output VAL into OBS and verify it is in range MIN...MAX that is supposed
 203    to be compile time constant.
 204    Be host independent, limit range to 31bits.  */
 205
 206 static inline void
 207 streamer_write_hwi_in_range (struct lto_output_stream *obs,
 208                                   HOST_WIDE_INT min,
 209                                   HOST_WIDE_INT max,
 210                                   HOST_WIDE_INT val)
 211 {
 212   HOST_WIDE_INT range = max - min;
 213
 214   gcc_checking_assert (val >= min && val <= max && range > 0
 215                        && range < 0x7fffffff);
 216
 217   val -= min;
 218   streamer_write_uhwi_stream (obs, (unsigned HOST_WIDE_INT) val);
 219 }
 220
 221 /* Input VAL into OBS and verify it is in range MIN...MAX that is supposed
 222    to be compile time constant.  PURPOSE is used for error reporting.  */
 223
 224 static inline HOST_WIDE_INT
 225 streamer_read_hwi_in_range (struct lto_input_block *ib,
 226                                  const char *purpose,
 227                                  HOST_WIDE_INT min,
 228                                  HOST_WIDE_INT max)
 229 {
 230   HOST_WIDE_INT range = max - min;
 231   unsigned HOST_WIDE_INT uval = streamer_read_uhwi (ib);
 232
 233   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 234
 235   HOST_WIDE_INT val = (HOST_WIDE_INT) (uval + (unsigned HOST_WIDE_INT) min);
 236   if (val < min || val > max)
 237     lto_value_range_error (purpose, val, min, max);
 238   return val;
 239 }
 240
 241 /* Output VAL into BP and verify it is in range MIN...MAX that is supposed
 242    to be compile time constant.
 243    Be host independent, limit range to 31bits.  */
 244
 245 static inline void
 246 bp_pack_int_in_range (struct bitpack_d *bp,
 247                       HOST_WIDE_INT min,
 248                       HOST_WIDE_INT max,
 249                       HOST_WIDE_INT val)
 250 {
 251   HOST_WIDE_INT range = max - min;
 252   int nbits = floor_log2 (range) + 1;
 253
 254   gcc_checking_assert (val >= min && val <= max && range > 0
 255                        && range < 0x7fffffff);
 256
 257   val -= min;
 258   bp_pack_value (bp, val, nbits);
 259 }
 260
 261 /* Input VAL into BP and verify it is in range MIN...MAX that is supposed
 262    to be compile time constant.  PURPOSE is used for error reporting.  */
 263
 264 static inline HOST_WIDE_INT
 265 bp_unpack_int_in_range (struct bitpack_d *bp,
 266                         const char *purpose,
 267                         HOST_WIDE_INT min,
 268                         HOST_WIDE_INT max)
 269 {
 270   HOST_WIDE_INT range = max - min;
 271   int nbits = floor_log2 (range) + 1;
 272   HOST_WIDE_INT val = bp_unpack_value (bp, nbits);
 273
 274   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 275
 276   if (val < min || val > max)
 277     lto_value_range_error (purpose, val, min, max);
 278   return val;
 279 }
 280
 281 /* Output VAL of type "enum enum_name" into OBS.
 282    Assume range 0...ENUM_LAST - 1.  */
 283 #define streamer_write_enum(obs,enum_name,enum_last,val) \
 284   streamer_write_hwi_in_range ((obs), 0, (int)(enum_last) - 1, (int)(val))
 285
 286 /* Input enum of type "enum enum_name" from IB.
 287    Assume range 0...ENUM_LAST - 1.  */
 288 #define streamer_read_enum(ib,enum_name,enum_last) \
 289   (enum enum_name)streamer_read_hwi_in_range ((ib), #enum_name, 0, \
 290                                               (int)(enum_last) - 1)
 291
 292 /* Output VAL of type "enum enum_name" into BP.
 293    Assume range 0...ENUM_LAST - 1.  */
 294 #define bp_pack_enum(bp,enum_name,enum_last,val) \
 295   bp_pack_int_in_range ((bp), 0, (int)(enum_last) - 1, (int)(val))
 296
 297 /* Input enum of type "enum enum_name" from BP.
 298    Assume range 0...ENUM_LAST - 1.  */
 299 #define bp_unpack_enum(bp,enum_name,enum_last) \
 300   (enum enum_name)bp_unpack_int_in_range ((bp), #enum_name, 0, \
 301                                         (int)(enum_last) - 1)
 302
 303 /* Output the start of a record with TAG to output block OB.  */
 304
 305 static inline void
 306 streamer_write_record_start (struct output_block *ob, enum LTO_tags tag)
 307 {
 308   streamer_write_enum (ob->main_stream, LTO_tags, LTO_NUM_TAGS, tag);
 309 }
 310
 311 /* Return the next tag in the input block IB.  */
 312
 313 static inline enum LTO_tags
 314 streamer_read_record_start (struct lto_input_block *ib)
 315 {
 316   return streamer_read_enum (ib, LTO_tags, LTO_NUM_TAGS);
 317 }
 318
 319 #endif  /* GCC_DATA_STREAMER_H  */