gcc/data-streamer.h

   1 /* Generic streaming support for various data types.
   2
   3    Copyright (C) 2011-2018 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 void streamer_write_wide_int (struct output_block *, const wide_int &);
  73 void streamer_write_widest_int (struct output_block *, const widest_int &);
  74
  75 /* In data-streamer-in.c  */
  76 const char *streamer_read_string (struct data_in *, struct lto_input_block *);
  77 const char *streamer_read_indexed_string (struct data_in *,
  78                                           struct lto_input_block *,
  79                                           unsigned int *);
  80 const char *bp_unpack_indexed_string (struct data_in *, struct bitpack_d *,
  81                                       unsigned int *);
  82 const char *bp_unpack_string (struct data_in *, struct bitpack_d *);
  83 unsigned HOST_WIDE_INT streamer_read_uhwi (struct lto_input_block *);
  84 HOST_WIDE_INT streamer_read_hwi (struct lto_input_block *);
  85 gcov_type streamer_read_gcov_count (struct lto_input_block *);
  86 wide_int streamer_read_wide_int (struct lto_input_block *);
  87 widest_int streamer_read_widest_int (struct lto_input_block *);
  88
  89 /* Returns a new bit-packing context for bit-packing into S.  */
  90 static inline struct bitpack_d
  91 bitpack_create (struct lto_output_stream *s)
  92 {
  93   struct bitpack_d bp;
  94   bp.pos = 0;
  95   bp.word = 0;
  96   bp.stream = (void *)s;
  97   return bp;
  98 }
  99
 100 /* Pack the NBITS bit sized value VAL into the bit-packing context BP.  */
 101 static inline void
 102 bp_pack_value (struct bitpack_d *bp, bitpack_word_t val, unsigned nbits)
 103 {
 104   bitpack_word_t word = bp->word;
 105   int pos = bp->pos;
 106
 107   /* Verify that VAL fits in the NBITS.  */
 108   gcc_checking_assert (nbits == BITS_PER_BITPACK_WORD
 109                        || !(val & ~(((bitpack_word_t)1<<nbits)-1)));
 110
 111   /* If val does not fit into the current bitpack word switch to the
 112      next one.  */
 113   if (pos + nbits > BITS_PER_BITPACK_WORD)
 114     {
 115       streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 116                                   word);
 117       word = val;
 118       pos = nbits;
 119     }
 120   else
 121     {
 122       word |= val << pos;
 123       pos += nbits;
 124     }
 125   bp->word = word;
 126   bp->pos = pos;
 127 }
 128
 129 /* Pack VAL into the bit-packing context BP, using NBITS for each
 130    coefficient.  */
 131 static inline void
 132 bp_pack_poly_value (struct bitpack_d *bp,
 133                     const poly_int<NUM_POLY_INT_COEFFS, bitpack_word_t> &val,
 134                     unsigned nbits)
 135 {
 136   for (int i = 0; i < NUM_POLY_INT_COEFFS; ++i)
 137     bp_pack_value (bp, val.coeffs[i], nbits);
 138 }
 139
 140 /* Finishes bit-packing of BP.  */
 141 static inline void
 142 streamer_write_bitpack (struct bitpack_d *bp)
 143 {
 144   streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 145                               bp->word);
 146   bp->word = 0;
 147   bp->pos = 0;
 148 }
 149
 150 /* Returns a new bit-packing context for bit-unpacking from IB.  */
 151 static inline struct bitpack_d
 152 streamer_read_bitpack (struct lto_input_block *ib)
 153 {
 154   struct bitpack_d bp;
 155   bp.word = streamer_read_uhwi (ib);
 156   bp.pos = 0;
 157   bp.stream = (void *)ib;
 158   return bp;
 159 }
 160
 161 /* Unpacks NBITS bits from the bit-packing context BP and returns them.  */
 162 static inline bitpack_word_t
 163 bp_unpack_value (struct bitpack_d *bp, unsigned nbits)
 164 {
 165   bitpack_word_t mask, val;
 166   int pos = bp->pos;
 167
 168   mask = (nbits == BITS_PER_BITPACK_WORD
 169           ? (bitpack_word_t) -1
 170           : ((bitpack_word_t) 1 << nbits) - 1);
 171
 172   /* If there are not continuous nbits in the current bitpack word
 173      switch to the next one.  */
 174   if (pos + nbits > BITS_PER_BITPACK_WORD)
 175     {
 176       bp->word = val
 177         = streamer_read_uhwi ((struct lto_input_block *)bp->stream);
 178       bp->pos = nbits;
 179       return val & mask;
 180     }
 181   val = bp->word;
 182   val >>= pos;
 183   bp->pos = pos + nbits;
 184
 185   return val & mask;
 186 }
 187
 188 /* Unpacks a polynomial value from the bit-packing context BP in which each
 189    coefficient has NBITS bits.  */
 190 static inline poly_int<NUM_POLY_INT_COEFFS, bitpack_word_t>
 191 bp_unpack_poly_value (struct bitpack_d *bp, unsigned nbits)
 192 {
 193   poly_int_pod<NUM_POLY_INT_COEFFS, bitpack_word_t> x;
 194   for (int i = 0; i < NUM_POLY_INT_COEFFS; ++i)
 195     x.coeffs[i] = bp_unpack_value (bp, nbits);
 196   return x;
 197 }
 198
 199
 200 /* Write a character to the output block.  */
 201
 202 static inline void
 203 streamer_write_char_stream (struct lto_output_stream *obs, char c)
 204 {
 205   /* No space left.  */
 206   if (obs->left_in_block == 0)
 207     lto_append_block (obs);
 208
 209   /* Write the actual character.  */
 210   char *current_pointer = obs->current_pointer;
 211   *(current_pointer++) = c;
 212   obs->current_pointer = current_pointer;
 213   obs->total_size++;
 214   obs->left_in_block--;
 215 }
 216
 217
 218 /* Read byte from the input block.  */
 219
 220 static inline unsigned char
 221 streamer_read_uchar (struct lto_input_block *ib)
 222 {
 223   if (ib->p >= ib->len)
 224     lto_section_overrun (ib);
 225   return (ib->data[ib->p++]);
 226 }
 227
 228 /* Output VAL into OBS and verify it is in range MIN...MAX that is supposed
 229    to be compile time constant.
 230    Be host independent, limit range to 31bits.  */
 231
 232 static inline void
 233 streamer_write_hwi_in_range (struct lto_output_stream *obs,
 234                                   HOST_WIDE_INT min,
 235                                   HOST_WIDE_INT max,
 236                                   HOST_WIDE_INT val)
 237 {
 238   HOST_WIDE_INT range = max - min;
 239
 240   gcc_checking_assert (val >= min && val <= max && range > 0
 241                        && range < 0x7fffffff);
 242
 243   val -= min;
 244   streamer_write_uhwi_stream (obs, (unsigned HOST_WIDE_INT) val);
 245 }
 246
 247 /* Input VAL into OBS and verify it is in range MIN...MAX that is supposed
 248    to be compile time constant.  PURPOSE is used for error reporting.  */
 249
 250 static inline HOST_WIDE_INT
 251 streamer_read_hwi_in_range (struct lto_input_block *ib,
 252                                  const char *purpose,
 253                                  HOST_WIDE_INT min,
 254                                  HOST_WIDE_INT max)
 255 {
 256   HOST_WIDE_INT range = max - min;
 257   unsigned HOST_WIDE_INT uval = streamer_read_uhwi (ib);
 258
 259   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 260
 261   HOST_WIDE_INT val = (HOST_WIDE_INT) (uval + (unsigned HOST_WIDE_INT) min);
 262   if (val < min || val > max)
 263     lto_value_range_error (purpose, val, min, max);
 264   return val;
 265 }
 266
 267 /* Output VAL into BP and verify it is in range MIN...MAX that is supposed
 268    to be compile time constant.
 269    Be host independent, limit range to 31bits.  */
 270
 271 static inline void
 272 bp_pack_int_in_range (struct bitpack_d *bp,
 273                       HOST_WIDE_INT min,
 274                       HOST_WIDE_INT max,
 275                       HOST_WIDE_INT val)
 276 {
 277   HOST_WIDE_INT range = max - min;
 278   int nbits = floor_log2 (range) + 1;
 279
 280   gcc_checking_assert (val >= min && val <= max && range > 0
 281                        && range < 0x7fffffff);
 282
 283   val -= min;
 284   bp_pack_value (bp, val, nbits);
 285 }
 286
 287 /* Input VAL into BP and verify it is in range MIN...MAX that is supposed
 288    to be compile time constant.  PURPOSE is used for error reporting.  */
 289
 290 static inline HOST_WIDE_INT
 291 bp_unpack_int_in_range (struct bitpack_d *bp,
 292                         const char *purpose,
 293                         HOST_WIDE_INT min,
 294                         HOST_WIDE_INT max)
 295 {
 296   HOST_WIDE_INT range = max - min;
 297   int nbits = floor_log2 (range) + 1;
 298   HOST_WIDE_INT val = bp_unpack_value (bp, nbits);
 299
 300   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 301
 302   if (val < min || val > max)
 303     lto_value_range_error (purpose, val, min, max);
 304   return val;
 305 }
 306
 307 /* Output VAL of type "enum enum_name" into OBS.
 308    Assume range 0...ENUM_LAST - 1.  */
 309 #define streamer_write_enum(obs,enum_name,enum_last,val) \
 310   streamer_write_hwi_in_range ((obs), 0, (int)(enum_last) - 1, (int)(val))
 311
 312 /* Input enum of type "enum enum_name" from IB.
 313    Assume range 0...ENUM_LAST - 1.  */
 314 #define streamer_read_enum(ib,enum_name,enum_last) \
 315   (enum enum_name)streamer_read_hwi_in_range ((ib), #enum_name, 0, \
 316                                               (int)(enum_last) - 1)
 317
 318 /* Output VAL of type "enum enum_name" into BP.
 319    Assume range 0...ENUM_LAST - 1.  */
 320 #define bp_pack_enum(bp,enum_name,enum_last,val) \
 321   bp_pack_int_in_range ((bp), 0, (int)(enum_last) - 1, (int)(val))
 322
 323 /* Input enum of type "enum enum_name" from BP.
 324    Assume range 0...ENUM_LAST - 1.  */
 325 #define bp_unpack_enum(bp,enum_name,enum_last) \
 326   (enum enum_name)bp_unpack_int_in_range ((bp), #enum_name, 0, \
 327                                         (int)(enum_last) - 1)
 328
 329 /* Output the start of a record with TAG to output block OB.  */
 330
 331 static inline void
 332 streamer_write_record_start (struct output_block *ob, enum LTO_tags tag)
 333 {
 334   streamer_write_enum (ob->main_stream, LTO_tags, LTO_NUM_TAGS, tag);
 335 }
 336
 337 /* Return the next tag in the input block IB.  */
 338
 339 static inline enum LTO_tags
 340 streamer_read_record_start (struct lto_input_block *ib)
 341 {
 342   return streamer_read_enum (ib, LTO_tags, LTO_NUM_TAGS);
 343 }
 344
 345 #endif  /* GCC_DATA_STREAMER_H  */