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_gcov_count (struct output_block *, gcov_type);
  67 void streamer_write_string (struct output_block *, struct lto_output_stream *,
  68                             const char *, bool);
  69 unsigned streamer_string_index (struct output_block *, const char *,
  70                                 unsigned int, bool);
  71 void streamer_write_string_with_length (struct output_block *,
  72                                         struct lto_output_stream *,
  73                                         const char *, unsigned int, bool);
  74 void bp_pack_string_with_length (struct output_block *, struct bitpack_d *,
  75                                  const char *, unsigned int, bool);
  76 void bp_pack_string (struct output_block *, struct bitpack_d *,
  77                      const char *, bool);
  78 void streamer_write_uhwi_stream (struct lto_output_stream *,
  79                                  unsigned HOST_WIDE_INT);
  80 void streamer_write_hwi_stream (struct lto_output_stream *, HOST_WIDE_INT);
  81 void streamer_write_gcov_count_stream (struct lto_output_stream *, gcov_type);
  82
  83 /* In data-streamer-in.c  */
  84 const char *string_for_index (struct data_in *, unsigned int, unsigned int *);
  85 const char *streamer_read_string (struct data_in *, struct lto_input_block *);
  86 const char *streamer_read_indexed_string (struct data_in *,
  87                                           struct lto_input_block *,
  88                                           unsigned int *);
  89 const char *bp_unpack_indexed_string (struct data_in *, struct bitpack_d *,
  90                                       unsigned int *);
  91 const char *bp_unpack_string (struct data_in *, struct bitpack_d *);
  92 unsigned HOST_WIDE_INT streamer_read_uhwi (struct lto_input_block *);
  93 HOST_WIDE_INT streamer_read_hwi (struct lto_input_block *);
  94 gcov_type streamer_read_gcov_count (struct lto_input_block *);
  95
  96 /* Returns a hash code for P.  Adapted from libiberty's htab_hash_string
  97    to support strings that may not end in '\0'.  */
  98
  99 static inline hashval_t
 100 hash_string_slot_node (const void *p)
 101 {
 102   const struct string_slot *ds = (const struct string_slot *) p;
 103   hashval_t r = ds->len;
 104   int i;
 105
 106   for (i = 0; i < ds->len; i++)
 107      r = r * 67 + (unsigned)ds->s[i] - 113;
 108   return r;
 109 }
 110
 111 /* Returns nonzero if P1 and P2 are equal.  */
 112
 113 static inline int
 114 eq_string_slot_node (const void *p1, const void *p2)
 115 {
 116   const struct string_slot *ds1 = (const struct string_slot *) p1;
 117   const struct string_slot *ds2 = (const struct string_slot *) p2;
 118
 119   if (ds1->len == ds2->len)
 120     return memcmp (ds1->s, ds2->s, ds1->len) == 0;
 121
 122   return 0;
 123 }
 124
 125 /* Returns a new bit-packing context for bit-packing into S.  */
 126 static inline struct bitpack_d
 127 bitpack_create (struct lto_output_stream *s)
 128 {
 129   struct bitpack_d bp;
 130   bp.pos = 0;
 131   bp.word = 0;
 132   bp.stream = (void *)s;
 133   return bp;
 134 }
 135
 136 /* Pack the NBITS bit sized value VAL into the bit-packing context BP.  */
 137 static inline void
 138 bp_pack_value (struct bitpack_d *bp, bitpack_word_t val, unsigned nbits)
 139 {
 140   bitpack_word_t word = bp->word;
 141   int pos = bp->pos;
 142
 143   /* Verify that VAL fits in the NBITS.  */
 144   gcc_checking_assert (nbits == BITS_PER_BITPACK_WORD
 145                        || !(val & ~(((bitpack_word_t)1<<nbits)-1)));
 146
 147   /* If val does not fit into the current bitpack word switch to the
 148      next one.  */
 149   if (pos + nbits > BITS_PER_BITPACK_WORD)
 150     {
 151       streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 152                                   word);
 153       word = val;
 154       pos = nbits;
 155     }
 156   else
 157     {
 158       word |= val << pos;
 159       pos += nbits;
 160     }
 161   bp->word = word;
 162   bp->pos = pos;
 163 }
 164
 165 /* Finishes bit-packing of BP.  */
 166 static inline void
 167 streamer_write_bitpack (struct bitpack_d *bp)
 168 {
 169   streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 170                               bp->word);
 171   bp->word = 0;
 172   bp->pos = 0;
 173 }
 174
 175 /* Returns a new bit-packing context for bit-unpacking from IB.  */
 176 static inline struct bitpack_d
 177 streamer_read_bitpack (struct lto_input_block *ib)
 178 {
 179   struct bitpack_d bp;
 180   bp.word = streamer_read_uhwi (ib);
 181   bp.pos = 0;
 182   bp.stream = (void *)ib;
 183   return bp;
 184 }
 185
 186 /* Unpacks NBITS bits from the bit-packing context BP and returns them.  */
 187 static inline bitpack_word_t
 188 bp_unpack_value (struct bitpack_d *bp, unsigned nbits)
 189 {
 190   bitpack_word_t mask, val;
 191   int pos = bp->pos;
 192
 193   mask = (nbits == BITS_PER_BITPACK_WORD
 194           ? (bitpack_word_t) -1
 195           : ((bitpack_word_t) 1 << nbits) - 1);
 196
 197   /* If there are not continuous nbits in the current bitpack word
 198      switch to the next one.  */
 199   if (pos + nbits > BITS_PER_BITPACK_WORD)
 200     {
 201       bp->word = val
 202         = streamer_read_uhwi ((struct lto_input_block *)bp->stream);
 203       bp->pos = nbits;
 204       return val & mask;
 205     }
 206   val = bp->word;
 207   val >>= pos;
 208   bp->pos = pos + nbits;
 209
 210   return val & mask;
 211 }
 212
 213
 214 /* Write a character to the output block.  */
 215
 216 static inline void
 217 streamer_write_char_stream (struct lto_output_stream *obs, char c)
 218 {
 219   /* No space left.  */
 220   if (obs->left_in_block == 0)
 221     lto_append_block (obs);
 222
 223   /* Write the actual character.  */
 224   *obs->current_pointer = c;
 225   obs->current_pointer++;
 226   obs->total_size++;
 227   obs->left_in_block--;
 228 }
 229
 230
 231 /* Read byte from the input block.  */
 232
 233 static inline unsigned char
 234 streamer_read_uchar (struct lto_input_block *ib)
 235 {
 236   if (ib->p >= ib->len)
 237     lto_section_overrun (ib);
 238   return (ib->data[ib->p++]);
 239 }
 240
 241 /* Output VAL into OBS 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 streamer_write_hwi_in_range (struct lto_output_stream *obs,
 247                                   HOST_WIDE_INT min,
 248                                   HOST_WIDE_INT max,
 249                                   HOST_WIDE_INT val)
 250 {
 251   HOST_WIDE_INT range = max - min;
 252
 253   gcc_checking_assert (val >= min && val <= max && range > 0
 254                        && range < 0x7fffffff);
 255
 256   val -= min;
 257   streamer_write_char_stream (obs, val & 255);
 258   if (range >= 0xff)
 259     streamer_write_char_stream (obs, (val >> 8) & 255);
 260   if (range >= 0xffff)
 261     streamer_write_char_stream (obs, (val >> 16) & 255);
 262   if (range >= 0xffffff)
 263     streamer_write_char_stream (obs, (val >> 24) & 255);
 264 }
 265
 266 /* Input VAL into OBS and verify it is in range MIN...MAX that is supposed
 267    to be compile time constant.  PURPOSE is used for error reporting.  */
 268
 269 static inline HOST_WIDE_INT
 270 streamer_read_hwi_in_range (struct lto_input_block *ib,
 271                                  const char *purpose,
 272                                  HOST_WIDE_INT min,
 273                                  HOST_WIDE_INT max)
 274 {
 275   HOST_WIDE_INT range = max - min;
 276   HOST_WIDE_INT val = streamer_read_uchar (ib);
 277
 278   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 279
 280   if (range >= 0xff)
 281     val |= ((HOST_WIDE_INT)streamer_read_uchar (ib)) << 8;
 282   if (range >= 0xffff)
 283     val |= ((HOST_WIDE_INT)streamer_read_uchar (ib)) << 16;
 284   if (range >= 0xffffff)
 285     val |= ((HOST_WIDE_INT)streamer_read_uchar (ib)) << 24;
 286   val += min;
 287   if (val < min || val > max)
 288     lto_value_range_error (purpose, val, min, max);
 289   return val;
 290 }
 291
 292 /* Output VAL into BP and verify it is in range MIN...MAX that is supposed
 293    to be compile time constant.
 294    Be host independent, limit range to 31bits.  */
 295
 296 static inline void
 297 bp_pack_int_in_range (struct bitpack_d *bp,
 298                       HOST_WIDE_INT min,
 299                       HOST_WIDE_INT max,
 300                       HOST_WIDE_INT val)
 301 {
 302   HOST_WIDE_INT range = max - min;
 303   int nbits = floor_log2 (range) + 1;
 304
 305   gcc_checking_assert (val >= min && val <= max && range > 0
 306                        && range < 0x7fffffff);
 307
 308   val -= min;
 309   bp_pack_value (bp, val, nbits);
 310 }
 311
 312 /* Input VAL into BP and verify it is in range MIN...MAX that is supposed
 313    to be compile time constant.  PURPOSE is used for error reporting.  */
 314
 315 static inline HOST_WIDE_INT
 316 bp_unpack_int_in_range (struct bitpack_d *bp,
 317                         const char *purpose,
 318                         HOST_WIDE_INT min,
 319                         HOST_WIDE_INT max)
 320 {
 321   HOST_WIDE_INT range = max - min;
 322   int nbits = floor_log2 (range) + 1;
 323   HOST_WIDE_INT val = bp_unpack_value (bp, nbits);
 324
 325   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 326
 327   if (val < min || val > max)
 328     lto_value_range_error (purpose, val, min, max);
 329   return val;
 330 }
 331
 332 /* Output VAL of type "enum enum_name" into OBS.
 333    Assume range 0...ENUM_LAST - 1.  */
 334 #define streamer_write_enum(obs,enum_name,enum_last,val) \
 335   streamer_write_hwi_in_range ((obs), 0, (int)(enum_last) - 1, (int)(val))
 336
 337 /* Input enum of type "enum enum_name" from IB.
 338    Assume range 0...ENUM_LAST - 1.  */
 339 #define streamer_read_enum(ib,enum_name,enum_last) \
 340   (enum enum_name)streamer_read_hwi_in_range ((ib), #enum_name, 0, \
 341                                               (int)(enum_last) - 1)
 342
 343 /* Output VAL of type "enum enum_name" into BP.
 344    Assume range 0...ENUM_LAST - 1.  */
 345 #define bp_pack_enum(bp,enum_name,enum_last,val) \
 346   bp_pack_int_in_range ((bp), 0, (int)(enum_last) - 1, (int)(val))
 347
 348 /* Input enum of type "enum enum_name" from BP.
 349    Assume range 0...ENUM_LAST - 1.  */
 350 #define bp_unpack_enum(bp,enum_name,enum_last) \
 351   (enum enum_name)bp_unpack_int_in_range ((bp), #enum_name, 0, \
 352                                         (int)(enum_last) - 1)
 353
 354 /* Output the start of a record with TAG to output block OB.  */
 355
 356 static inline void
 357 streamer_write_record_start (struct output_block *ob, enum LTO_tags tag)
 358 {
 359   streamer_write_enum (ob->main_stream, LTO_tags, LTO_NUM_TAGS, tag);
 360 }
 361
 362 /* Return the next tag in the input block IB.  */
 363
 364 static inline enum LTO_tags
 365 streamer_read_record_start (struct lto_input_block *ib)
 366 {
 367   return streamer_read_enum (ib, LTO_tags, LTO_NUM_TAGS);
 368 }
 369
 370 #endif  /* GCC_DATA_STREAMER_H  */