gcc/data-streamer.h

   1 /* Generic streaming support for various data types.
   2
   3    Copyright (C) 2011-2013 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 "vec.h"
  26 #include "lto-streamer.h"
  27
  28 /* Data structures used to pack values and bitflags into a vector of
  29    words.  Used to stream values of a fixed number of bits in a space
  30    efficient way.  */
  31 static unsigned const BITS_PER_BITPACK_WORD = HOST_BITS_PER_WIDE_INT;
  32
  33 typedef unsigned HOST_WIDE_INT bitpack_word_t;
  34
  35 struct bitpack_d
  36 {
  37   /* The position of the first unused or unconsumed bit in the word.  */
  38   unsigned pos;
  39
  40   /* The current word we are (un)packing.  */
  41   bitpack_word_t word;
  42
  43   /* The lto_output_stream or the lto_input_block we are streaming to/from.  */
  44   void *stream;
  45 };
  46
  47
  48 /* String hashing.  */
  49 struct string_slot
  50 {
  51   const char *s;
  52   int len;
  53   unsigned int slot_num;
  54 };
  55
  56 /* In data-streamer.c  */
  57 void bp_pack_var_len_unsigned (struct bitpack_d *, unsigned HOST_WIDE_INT);
  58 void bp_pack_var_len_int (struct bitpack_d *, HOST_WIDE_INT);
  59 unsigned HOST_WIDE_INT bp_unpack_var_len_unsigned (struct bitpack_d *);
  60 HOST_WIDE_INT bp_unpack_var_len_int (struct bitpack_d *);
  61
  62 /* In data-streamer-out.c  */
  63 void streamer_write_zero (struct output_block *);
  64 void streamer_write_uhwi (struct output_block *, unsigned HOST_WIDE_INT);
  65 void streamer_write_hwi (struct output_block *, HOST_WIDE_INT);
  66 void streamer_write_string (struct output_block *, struct lto_output_stream *,
  67                             const char *, bool);
  68 unsigned streamer_string_index (struct output_block *, const char *,
  69                                 unsigned int, bool);
  70 void streamer_write_string_with_length (struct output_block *,
  71                                         struct lto_output_stream *,
  72                                         const char *, unsigned int, bool);
  73 void bp_pack_string_with_length (struct output_block *, struct bitpack_d *,
  74                                  const char *, unsigned int, bool);
  75 void bp_pack_string (struct output_block *, struct bitpack_d *,
  76                      const char *, bool);
  77 void streamer_write_uhwi_stream (struct lto_output_stream *,
  78                                  unsigned HOST_WIDE_INT);
  79 void streamer_write_hwi_stream (struct lto_output_stream *, HOST_WIDE_INT);
  80
  81 /* In data-streamer-in.c  */
  82 const char *string_for_index (struct data_in *, unsigned int, unsigned int *);
  83 const char *streamer_read_string (struct data_in *, struct lto_input_block *);
  84 const char *streamer_read_indexed_string (struct data_in *,
  85                                           struct lto_input_block *,
  86                                           unsigned int *);
  87 const char *bp_unpack_indexed_string (struct data_in *, struct bitpack_d *,
  88                                       unsigned int *);
  89 const char *bp_unpack_string (struct data_in *, struct bitpack_d *);
  90 unsigned HOST_WIDE_INT streamer_read_uhwi (struct lto_input_block *);
  91 HOST_WIDE_INT streamer_read_hwi (struct lto_input_block *);
  92
  93 /* Returns a hash code for P.  Adapted from libiberty's htab_hash_string
  94    to support strings that may not end in '\0'.  */
  95
  96 static inline hashval_t
  97 hash_string_slot_node (const void *p)
  98 {
  99   const struct string_slot *ds = (const struct string_slot *) p;
 100   hashval_t r = ds->len;
 101   int i;
 102
 103   for (i = 0; i < ds->len; i++)
 104      r = r * 67 + (unsigned)ds->s[i] - 113;
 105   return r;
 106 }
 107
 108 /* Returns nonzero if P1 and P2 are equal.  */
 109
 110 static inline int
 111 eq_string_slot_node (const void *p1, const void *p2)
 112 {
 113   const struct string_slot *ds1 = (const struct string_slot *) p1;
 114   const struct string_slot *ds2 = (const struct string_slot *) p2;
 115
 116   if (ds1->len == ds2->len)
 117     return memcmp (ds1->s, ds2->s, ds1->len) == 0;
 118
 119   return 0;
 120 }
 121
 122 /* Returns a new bit-packing context for bit-packing into S.  */
 123 static inline struct bitpack_d
 124 bitpack_create (struct lto_output_stream *s)
 125 {
 126   struct bitpack_d bp;
 127   bp.pos = 0;
 128   bp.word = 0;
 129   bp.stream = (void *)s;
 130   return bp;
 131 }
 132
 133 /* Pack the NBITS bit sized value VAL into the bit-packing context BP.  */
 134 static inline void
 135 bp_pack_value (struct bitpack_d *bp, bitpack_word_t val, unsigned nbits)
 136 {
 137   bitpack_word_t word = bp->word;
 138   int pos = bp->pos;
 139
 140   /* Verify that VAL fits in the NBITS.  */
 141   gcc_checking_assert (nbits == BITS_PER_BITPACK_WORD
 142                        || !(val & ~(((bitpack_word_t)1<<nbits)-1)));
 143
 144   /* If val does not fit into the current bitpack word switch to the
 145      next one.  */
 146   if (pos + nbits > BITS_PER_BITPACK_WORD)
 147     {
 148       streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 149                                   word);
 150       word = val;
 151       pos = nbits;
 152     }
 153   else
 154     {
 155       word |= val << pos;
 156       pos += nbits;
 157     }
 158   bp->word = word;
 159   bp->pos = pos;
 160 }
 161
 162 /* Finishes bit-packing of BP.  */
 163 static inline void
 164 streamer_write_bitpack (struct bitpack_d *bp)
 165 {
 166   streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 167                               bp->word);
 168   bp->word = 0;
 169   bp->pos = 0;
 170 }
 171
 172 /* Returns a new bit-packing context for bit-unpacking from IB.  */
 173 static inline struct bitpack_d
 174 streamer_read_bitpack (struct lto_input_block *ib)
 175 {
 176   struct bitpack_d bp;
 177   bp.word = streamer_read_uhwi (ib);
 178   bp.pos = 0;
 179   bp.stream = (void *)ib;
 180   return bp;
 181 }
 182
 183 /* Unpacks NBITS bits from the bit-packing context BP and returns them.  */
 184 static inline bitpack_word_t
 185 bp_unpack_value (struct bitpack_d *bp, unsigned nbits)
 186 {
 187   bitpack_word_t mask, val;
 188   int pos = bp->pos;
 189
 190   mask = (nbits == BITS_PER_BITPACK_WORD
 191           ? (bitpack_word_t) -1
 192           : ((bitpack_word_t) 1 << nbits) - 1);
 193
 194   /* If there are not continuous nbits in the current bitpack word
 195      switch to the next one.  */
 196   if (pos + nbits > BITS_PER_BITPACK_WORD)
 197     {
 198       bp->word = val
 199         = streamer_read_uhwi ((struct lto_input_block *)bp->stream);
 200       bp->pos = nbits;
 201       return val & mask;
 202     }
 203   val = bp->word;
 204   val >>= pos;
 205   bp->pos = pos + nbits;
 206
 207   return val & mask;
 208 }
 209
 210
 211 /* Write a character to the output block.  */
 212
 213 static inline void
 214 streamer_write_char_stream (struct lto_output_stream *obs, char c)
 215 {
 216   /* No space left.  */
 217   if (obs->left_in_block == 0)
 218     lto_append_block (obs);
 219
 220   /* Write the actual character.  */
 221   *obs->current_pointer = c;
 222   obs->current_pointer++;
 223   obs->total_size++;
 224   obs->left_in_block--;
 225 }
 226
 227
 228 /* Read byte from the input block.  */
 229
 230 static inline unsigned char
 231 streamer_read_uchar (struct lto_input_block *ib)
 232 {
 233   if (ib->p >= ib->len)
 234     lto_section_overrun (ib);
 235   return (ib->data[ib->p++]);
 236 }
 237
 238 /* Output VAL into OBS and verify it is in range MIN...MAX that is supposed
 239    to be compile time constant.
 240    Be host independent, limit range to 31bits.  */
 241
 242 static inline void
 243 streamer_write_hwi_in_range (struct lto_output_stream *obs,
 244                                   HOST_WIDE_INT min,
 245                                   HOST_WIDE_INT max,
 246                                   HOST_WIDE_INT val)
 247 {
 248   HOST_WIDE_INT range = max - min;
 249
 250   gcc_checking_assert (val >= min && val <= max && range > 0
 251                        && range < 0x7fffffff);
 252
 253   val -= min;
 254   streamer_write_char_stream (obs, val & 255);
 255   if (range >= 0xff)
 256     streamer_write_char_stream (obs, (val >> 8) & 255);
 257   if (range >= 0xffff)
 258     streamer_write_char_stream (obs, (val >> 16) & 255);
 259   if (range >= 0xffffff)
 260     streamer_write_char_stream (obs, (val >> 24) & 255);
 261 }
 262
 263 /* Input VAL into OBS and verify it is in range MIN...MAX that is supposed
 264    to be compile time constant.  PURPOSE is used for error reporting.  */
 265
 266 static inline HOST_WIDE_INT
 267 streamer_read_hwi_in_range (struct lto_input_block *ib,
 268                                  const char *purpose,
 269                                  HOST_WIDE_INT min,
 270                                  HOST_WIDE_INT max)
 271 {
 272   HOST_WIDE_INT range = max - min;
 273   HOST_WIDE_INT val = streamer_read_uchar (ib);
 274
 275   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 276
 277   if (range >= 0xff)
 278     val |= ((HOST_WIDE_INT)streamer_read_uchar (ib)) << 8;
 279   if (range >= 0xffff)
 280     val |= ((HOST_WIDE_INT)streamer_read_uchar (ib)) << 16;
 281   if (range >= 0xffffff)
 282     val |= ((HOST_WIDE_INT)streamer_read_uchar (ib)) << 24;
 283   val += min;
 284   if (val < min || val > max)
 285     lto_value_range_error (purpose, val, min, max);
 286   return val;
 287 }
 288
 289 /* Output VAL into BP and verify it is in range MIN...MAX that is supposed
 290    to be compile time constant.
 291    Be host independent, limit range to 31bits.  */
 292
 293 static inline void
 294 bp_pack_int_in_range (struct bitpack_d *bp,
 295                       HOST_WIDE_INT min,
 296                       HOST_WIDE_INT max,
 297                       HOST_WIDE_INT val)
 298 {
 299   HOST_WIDE_INT range = max - min;
 300   int nbits = floor_log2 (range) + 1;
 301
 302   gcc_checking_assert (val >= min && val <= max && range > 0
 303                        && range < 0x7fffffff);
 304
 305   val -= min;
 306   bp_pack_value (bp, val, nbits);
 307 }
 308
 309 /* Input VAL into BP and verify it is in range MIN...MAX that is supposed
 310    to be compile time constant.  PURPOSE is used for error reporting.  */
 311
 312 static inline HOST_WIDE_INT
 313 bp_unpack_int_in_range (struct bitpack_d *bp,
 314                         const char *purpose,
 315                         HOST_WIDE_INT min,
 316                         HOST_WIDE_INT max)
 317 {
 318   HOST_WIDE_INT range = max - min;
 319   int nbits = floor_log2 (range) + 1;
 320   HOST_WIDE_INT val = bp_unpack_value (bp, nbits);
 321
 322   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 323
 324   if (val < min || val > max)
 325     lto_value_range_error (purpose, val, min, max);
 326   return val;
 327 }
 328
 329 /* Output VAL of type "enum enum_name" into OBS.
 330    Assume range 0...ENUM_LAST - 1.  */
 331 #define streamer_write_enum(obs,enum_name,enum_last,val) \
 332   streamer_write_hwi_in_range ((obs), 0, (int)(enum_last) - 1, (int)(val))
 333
 334 /* Input enum of type "enum enum_name" from IB.
 335    Assume range 0...ENUM_LAST - 1.  */
 336 #define streamer_read_enum(ib,enum_name,enum_last) \
 337   (enum enum_name)streamer_read_hwi_in_range ((ib), #enum_name, 0, \
 338                                               (int)(enum_last) - 1)
 339
 340 /* Output VAL of type "enum enum_name" into BP.
 341    Assume range 0...ENUM_LAST - 1.  */
 342 #define bp_pack_enum(bp,enum_name,enum_last,val) \
 343   bp_pack_int_in_range ((bp), 0, (int)(enum_last) - 1, (int)(val))
 344
 345 /* Input enum of type "enum enum_name" from BP.
 346    Assume range 0...ENUM_LAST - 1.  */
 347 #define bp_unpack_enum(bp,enum_name,enum_last) \
 348   (enum enum_name)bp_unpack_int_in_range ((bp), #enum_name, 0, \
 349                                         (int)(enum_last) - 1)
 350
 351 /* Output the start of a record with TAG to output block OB.  */
 352
 353 static inline void
 354 streamer_write_record_start (struct output_block *ob, enum LTO_tags tag)
 355 {
 356   streamer_write_enum (ob->main_stream, LTO_tags, LTO_NUM_TAGS, tag);
 357 }
 358
 359 /* Return the next tag in the input block IB.  */
 360
 361 static inline enum LTO_tags
 362 streamer_read_record_start (struct lto_input_block *ib)
 363 {
 364   return streamer_read_enum (ib, LTO_tags, LTO_NUM_TAGS);
 365 }
 366
 367 #endif  /* GCC_DATA_STREAMER_H  */