gcc/data-streamer.h

   1 /* Generic streaming support for various data types.
   2
   3    Copyright (C) 2011-2020 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_poly_uint64 (struct output_block *, poly_uint64);
  57 void streamer_write_gcov_count (struct output_block *, gcov_type);
  58 void streamer_write_string (struct output_block *, struct lto_output_stream *,
  59                             const char *, bool);
  60 void streamer_write_string_with_length (struct output_block *,
  61                                         struct lto_output_stream *,
  62                                         const char *, unsigned int, bool);
  63 void bp_pack_string_with_length (struct output_block *, struct bitpack_d *,
  64                                  const char *, unsigned int, bool);
  65 void bp_pack_string (struct output_block *, struct bitpack_d *,
  66                      const char *, bool);
  67 void streamer_write_uhwi_stream (struct lto_output_stream *,
  68                                  unsigned HOST_WIDE_INT);
  69 void streamer_write_hwi_stream (struct lto_output_stream *, HOST_WIDE_INT);
  70 void streamer_write_gcov_count_stream (struct lto_output_stream *, gcov_type);
  71 void streamer_write_data_stream (struct lto_output_stream *, const void *,
  72                                  size_t);
  73 void streamer_write_wide_int (struct output_block *, const wide_int &);
  74 void streamer_write_widest_int (struct output_block *, const widest_int &);
  75
  76 /* In data-streamer-in.c  */
  77 const char *streamer_read_string (class data_in *, class lto_input_block *);
  78 const char *streamer_read_indexed_string (class data_in *,
  79                                           class lto_input_block *,
  80                                           unsigned int *);
  81 const char *bp_unpack_indexed_string (class data_in *, struct bitpack_d *,
  82                                       unsigned int *);
  83 const char *bp_unpack_string (class data_in *, struct bitpack_d *);
  84 unsigned HOST_WIDE_INT streamer_read_uhwi (class lto_input_block *);
  85 HOST_WIDE_INT streamer_read_hwi (class lto_input_block *);
  86 poly_uint64 streamer_read_poly_uint64 (class lto_input_block *);
  87 gcov_type streamer_read_gcov_count (class lto_input_block *);
  88 wide_int streamer_read_wide_int (class lto_input_block *);
  89 widest_int streamer_read_widest_int (class lto_input_block *);
  90
  91 /* Returns a new bit-packing context for bit-packing into S.  */
  92 static inline struct bitpack_d
  93 bitpack_create (struct lto_output_stream *s)
  94 {
  95   struct bitpack_d bp;
  96   bp.pos = 0;
  97   bp.word = 0;
  98   bp.stream = (void *)s;
  99   return bp;
 100 }
 101
 102 /* Pack the NBITS bit sized value VAL into the bit-packing context BP.  */
 103 static inline void
 104 bp_pack_value (struct bitpack_d *bp, bitpack_word_t val, unsigned nbits)
 105 {
 106   bitpack_word_t word = bp->word;
 107   int pos = bp->pos;
 108
 109   /* Verify that VAL fits in the NBITS.  */
 110   gcc_checking_assert (nbits == BITS_PER_BITPACK_WORD
 111                        || !(val & ~(((bitpack_word_t)1<<nbits)-1)));
 112
 113   /* If val does not fit into the current bitpack word switch to the
 114      next one.  */
 115   if (pos + nbits > BITS_PER_BITPACK_WORD)
 116     {
 117       streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 118                                   word);
 119       word = val;
 120       pos = nbits;
 121     }
 122   else
 123     {
 124       word |= val << pos;
 125       pos += nbits;
 126     }
 127   bp->word = word;
 128   bp->pos = pos;
 129 }
 130
 131 /* Pack VAL into the bit-packing context BP, using NBITS for each
 132    coefficient.  */
 133 static inline void
 134 bp_pack_poly_value (struct bitpack_d *bp,
 135                     const poly_int<NUM_POLY_INT_COEFFS, bitpack_word_t> &val,
 136                     unsigned nbits)
 137 {
 138   for (int i = 0; i < NUM_POLY_INT_COEFFS; ++i)
 139     bp_pack_value (bp, val.coeffs[i], nbits);
 140 }
 141
 142 /* Finishes bit-packing of BP.  */
 143 static inline void
 144 streamer_write_bitpack (struct bitpack_d *bp)
 145 {
 146   streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 147                               bp->word);
 148   bp->word = 0;
 149   bp->pos = 0;
 150 }
 151
 152 /* Returns a new bit-packing context for bit-unpacking from IB.  */
 153 static inline struct bitpack_d
 154 streamer_read_bitpack (class lto_input_block *ib)
 155 {
 156   struct bitpack_d bp;
 157   bp.word = streamer_read_uhwi (ib);
 158   bp.pos = 0;
 159   bp.stream = (void *)ib;
 160   return bp;
 161 }
 162
 163 /* Unpacks NBITS bits from the bit-packing context BP and returns them.  */
 164 static inline bitpack_word_t
 165 bp_unpack_value (struct bitpack_d *bp, unsigned nbits)
 166 {
 167   bitpack_word_t mask, val;
 168   int pos = bp->pos;
 169
 170   mask = (nbits == BITS_PER_BITPACK_WORD
 171           ? (bitpack_word_t) -1
 172           : ((bitpack_word_t) 1 << nbits) - 1);
 173
 174   /* If there are not continuous nbits in the current bitpack word
 175      switch to the next one.  */
 176   if (pos + nbits > BITS_PER_BITPACK_WORD)
 177     {
 178       bp->word = val
 179         = streamer_read_uhwi ((class lto_input_block *)bp->stream);
 180       bp->pos = nbits;
 181       return val & mask;
 182     }
 183   val = bp->word;
 184   val >>= pos;
 185   bp->pos = pos + nbits;
 186
 187   return val & mask;
 188 }
 189
 190 /* Unpacks a polynomial value from the bit-packing context BP in which each
 191    coefficient has NBITS bits.  */
 192 static inline poly_int<NUM_POLY_INT_COEFFS, bitpack_word_t>
 193 bp_unpack_poly_value (struct bitpack_d *bp, unsigned nbits)
 194 {
 195   poly_int_pod<NUM_POLY_INT_COEFFS, bitpack_word_t> x;
 196   for (int i = 0; i < NUM_POLY_INT_COEFFS; ++i)
 197     x.coeffs[i] = bp_unpack_value (bp, nbits);
 198   return x;
 199 }
 200
 201
 202 /* Write a character to the output block.  */
 203
 204 static inline void
 205 streamer_write_char_stream (struct lto_output_stream *obs, char c)
 206 {
 207   /* No space left.  */
 208   if (obs->left_in_block == 0)
 209     lto_append_block (obs);
 210
 211   /* Write the actual character.  */
 212   char *current_pointer = obs->current_pointer;
 213   *(current_pointer++) = c;
 214   obs->current_pointer = current_pointer;
 215   obs->total_size++;
 216   obs->left_in_block--;
 217 }
 218
 219
 220 /* Read byte from the input block.  */
 221
 222 static inline unsigned char
 223 streamer_read_uchar (class lto_input_block *ib)
 224 {
 225   if (ib->p >= ib->len)
 226     lto_section_overrun (ib);
 227   return (ib->data[ib->p++]);
 228 }
 229
 230 /* Output VAL into OBS and verify it is in range MIN...MAX that is supposed
 231    to be compile time constant.
 232    Be host independent, limit range to 31bits.  */
 233
 234 static inline void
 235 streamer_write_hwi_in_range (struct lto_output_stream *obs,
 236                                   HOST_WIDE_INT min,
 237                                   HOST_WIDE_INT max,
 238                                   HOST_WIDE_INT val)
 239 {
 240   HOST_WIDE_INT range = max - min;
 241
 242   gcc_checking_assert (val >= min && val <= max && range > 0
 243                        && range < 0x7fffffff);
 244
 245   val -= min;
 246   streamer_write_uhwi_stream (obs, (unsigned HOST_WIDE_INT) val);
 247 }
 248
 249 /* Input VAL into OBS and verify it is in range MIN...MAX that is supposed
 250    to be compile time constant.  PURPOSE is used for error reporting.  */
 251
 252 static inline HOST_WIDE_INT
 253 streamer_read_hwi_in_range (class lto_input_block *ib,
 254                                  const char *purpose,
 255                                  HOST_WIDE_INT min,
 256                                  HOST_WIDE_INT max)
 257 {
 258   HOST_WIDE_INT range = max - min;
 259   unsigned HOST_WIDE_INT uval = streamer_read_uhwi (ib);
 260
 261   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 262
 263   HOST_WIDE_INT val = (HOST_WIDE_INT) (uval + (unsigned HOST_WIDE_INT) min);
 264   if (val < min || val > max)
 265     lto_value_range_error (purpose, val, min, max);
 266   return val;
 267 }
 268
 269 /* Output VAL into BP and verify it is in range MIN...MAX that is supposed
 270    to be compile time constant.
 271    Be host independent, limit range to 31bits.  */
 272
 273 static inline void
 274 bp_pack_int_in_range (struct bitpack_d *bp,
 275                       HOST_WIDE_INT min,
 276                       HOST_WIDE_INT max,
 277                       HOST_WIDE_INT val)
 278 {
 279   HOST_WIDE_INT range = max - min;
 280   int nbits = floor_log2 (range) + 1;
 281
 282   gcc_checking_assert (val >= min && val <= max && range > 0
 283                        && range < 0x7fffffff);
 284
 285   val -= min;
 286   bp_pack_value (bp, val, nbits);
 287 }
 288
 289 /* Input VAL into BP and verify it is in range MIN...MAX that is supposed
 290    to be compile time constant.  PURPOSE is used for error reporting.  */
 291
 292 static inline HOST_WIDE_INT
 293 bp_unpack_int_in_range (struct bitpack_d *bp,
 294                         const char *purpose,
 295                         HOST_WIDE_INT min,
 296                         HOST_WIDE_INT max)
 297 {
 298   HOST_WIDE_INT range = max - min;
 299   int nbits = floor_log2 (range) + 1;
 300   HOST_WIDE_INT val = bp_unpack_value (bp, nbits);
 301
 302   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 303
 304   if (val < min || val > max)
 305     lto_value_range_error (purpose, val, min, max);
 306   return val;
 307 }
 308
 309 /* Output VAL of type "enum enum_name" into OBS.
 310    Assume range 0...ENUM_LAST - 1.  */
 311 #define streamer_write_enum(obs,enum_name,enum_last,val) \
 312   streamer_write_hwi_in_range ((obs), 0, (int)(enum_last) - 1, (int)(val))
 313
 314 /* Input enum of type "enum enum_name" from IB.
 315    Assume range 0...ENUM_LAST - 1.  */
 316 #define streamer_read_enum(ib,enum_name,enum_last) \
 317   (enum enum_name)streamer_read_hwi_in_range ((ib), #enum_name, 0, \
 318                                               (int)(enum_last) - 1)
 319
 320 /* Output VAL of type "enum enum_name" into BP.
 321    Assume range 0...ENUM_LAST - 1.  */
 322 #define bp_pack_enum(bp,enum_name,enum_last,val) \
 323   bp_pack_int_in_range ((bp), 0, (int)(enum_last) - 1, (int)(val))
 324
 325 /* Input enum of type "enum enum_name" from BP.
 326    Assume range 0...ENUM_LAST - 1.  */
 327 #define bp_unpack_enum(bp,enum_name,enum_last) \
 328   (enum enum_name)bp_unpack_int_in_range ((bp), #enum_name, 0, \
 329                                         (int)(enum_last) - 1)
 330
 331 /* Output the start of a record with TAG to output block OB.  */
 332
 333 static inline void
 334 streamer_write_record_start (struct output_block *ob, enum LTO_tags tag)
 335 {
 336   streamer_write_enum (ob->main_stream, LTO_tags, LTO_NUM_TAGS, tag);
 337 }
 338
 339 /* Return the next tag in the input block IB.  */
 340
 341 static inline enum LTO_tags
 342 streamer_read_record_start (class lto_input_block *ib)
 343 {
 344   return streamer_read_enum (ib, LTO_tags, LTO_NUM_TAGS);
 345 }
 346
 347 #endif  /* GCC_DATA_STREAMER_H  */