gcc/data-streamer.h

   1 /* Generic streaming support for various data types.
   2
   3    Copyright (C) 2011-2017 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 /* Finishes bit-packing of BP.  */
 130 static inline void
 131 streamer_write_bitpack (struct bitpack_d *bp)
 132 {
 133   streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 134                               bp->word);
 135   bp->word = 0;
 136   bp->pos = 0;
 137 }
 138
 139 /* Returns a new bit-packing context for bit-unpacking from IB.  */
 140 static inline struct bitpack_d
 141 streamer_read_bitpack (struct lto_input_block *ib)
 142 {
 143   struct bitpack_d bp;
 144   bp.word = streamer_read_uhwi (ib);
 145   bp.pos = 0;
 146   bp.stream = (void *)ib;
 147   return bp;
 148 }
 149
 150 /* Unpacks NBITS bits from the bit-packing context BP and returns them.  */
 151 static inline bitpack_word_t
 152 bp_unpack_value (struct bitpack_d *bp, unsigned nbits)
 153 {
 154   bitpack_word_t mask, val;
 155   int pos = bp->pos;
 156
 157   mask = (nbits == BITS_PER_BITPACK_WORD
 158           ? (bitpack_word_t) -1
 159           : ((bitpack_word_t) 1 << nbits) - 1);
 160
 161   /* If there are not continuous nbits in the current bitpack word
 162      switch to the next one.  */
 163   if (pos + nbits > BITS_PER_BITPACK_WORD)
 164     {
 165       bp->word = val
 166         = streamer_read_uhwi ((struct lto_input_block *)bp->stream);
 167       bp->pos = nbits;
 168       return val & mask;
 169     }
 170   val = bp->word;
 171   val >>= pos;
 172   bp->pos = pos + nbits;
 173
 174   return val & mask;
 175 }
 176
 177
 178 /* Write a character to the output block.  */
 179
 180 static inline void
 181 streamer_write_char_stream (struct lto_output_stream *obs, char c)
 182 {
 183   /* No space left.  */
 184   if (obs->left_in_block == 0)
 185     lto_append_block (obs);
 186
 187   /* Write the actual character.  */
 188   char *current_pointer = obs->current_pointer;
 189   *(current_pointer++) = c;
 190   obs->current_pointer = current_pointer;
 191   obs->total_size++;
 192   obs->left_in_block--;
 193 }
 194
 195
 196 /* Read byte from the input block.  */
 197
 198 static inline unsigned char
 199 streamer_read_uchar (struct lto_input_block *ib)
 200 {
 201   if (ib->p >= ib->len)
 202     lto_section_overrun (ib);
 203   return (ib->data[ib->p++]);
 204 }
 205
 206 /* Output VAL into OBS and verify it is in range MIN...MAX that is supposed
 207    to be compile time constant.
 208    Be host independent, limit range to 31bits.  */
 209
 210 static inline void
 211 streamer_write_hwi_in_range (struct lto_output_stream *obs,
 212                                   HOST_WIDE_INT min,
 213                                   HOST_WIDE_INT max,
 214                                   HOST_WIDE_INT val)
 215 {
 216   HOST_WIDE_INT range = max - min;
 217
 218   gcc_checking_assert (val >= min && val <= max && range > 0
 219                        && range < 0x7fffffff);
 220
 221   val -= min;
 222   streamer_write_uhwi_stream (obs, (unsigned HOST_WIDE_INT) val);
 223 }
 224
 225 /* Input VAL into OBS and verify it is in range MIN...MAX that is supposed
 226    to be compile time constant.  PURPOSE is used for error reporting.  */
 227
 228 static inline HOST_WIDE_INT
 229 streamer_read_hwi_in_range (struct lto_input_block *ib,
 230                                  const char *purpose,
 231                                  HOST_WIDE_INT min,
 232                                  HOST_WIDE_INT max)
 233 {
 234   HOST_WIDE_INT range = max - min;
 235   unsigned HOST_WIDE_INT uval = streamer_read_uhwi (ib);
 236
 237   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 238
 239   HOST_WIDE_INT val = (HOST_WIDE_INT) (uval + (unsigned HOST_WIDE_INT) min);
 240   if (val < min || val > max)
 241     lto_value_range_error (purpose, val, min, max);
 242   return val;
 243 }
 244
 245 /* Output VAL into BP and verify it is in range MIN...MAX that is supposed
 246    to be compile time constant.
 247    Be host independent, limit range to 31bits.  */
 248
 249 static inline void
 250 bp_pack_int_in_range (struct bitpack_d *bp,
 251                       HOST_WIDE_INT min,
 252                       HOST_WIDE_INT max,
 253                       HOST_WIDE_INT val)
 254 {
 255   HOST_WIDE_INT range = max - min;
 256   int nbits = floor_log2 (range) + 1;
 257
 258   gcc_checking_assert (val >= min && val <= max && range > 0
 259                        && range < 0x7fffffff);
 260
 261   val -= min;
 262   bp_pack_value (bp, val, nbits);
 263 }
 264
 265 /* Input VAL into BP and verify it is in range MIN...MAX that is supposed
 266    to be compile time constant.  PURPOSE is used for error reporting.  */
 267
 268 static inline HOST_WIDE_INT
 269 bp_unpack_int_in_range (struct bitpack_d *bp,
 270                         const char *purpose,
 271                         HOST_WIDE_INT min,
 272                         HOST_WIDE_INT max)
 273 {
 274   HOST_WIDE_INT range = max - min;
 275   int nbits = floor_log2 (range) + 1;
 276   HOST_WIDE_INT val = bp_unpack_value (bp, nbits);
 277
 278   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 279
 280   if (val < min || val > max)
 281     lto_value_range_error (purpose, val, min, max);
 282   return val;
 283 }
 284
 285 /* Output VAL of type "enum enum_name" into OBS.
 286    Assume range 0...ENUM_LAST - 1.  */
 287 #define streamer_write_enum(obs,enum_name,enum_last,val) \
 288   streamer_write_hwi_in_range ((obs), 0, (int)(enum_last) - 1, (int)(val))
 289
 290 /* Input enum of type "enum enum_name" from IB.
 291    Assume range 0...ENUM_LAST - 1.  */
 292 #define streamer_read_enum(ib,enum_name,enum_last) \
 293   (enum enum_name)streamer_read_hwi_in_range ((ib), #enum_name, 0, \
 294                                               (int)(enum_last) - 1)
 295
 296 /* Output VAL of type "enum enum_name" into BP.
 297    Assume range 0...ENUM_LAST - 1.  */
 298 #define bp_pack_enum(bp,enum_name,enum_last,val) \
 299   bp_pack_int_in_range ((bp), 0, (int)(enum_last) - 1, (int)(val))
 300
 301 /* Input enum of type "enum enum_name" from BP.
 302    Assume range 0...ENUM_LAST - 1.  */
 303 #define bp_unpack_enum(bp,enum_name,enum_last) \
 304   (enum enum_name)bp_unpack_int_in_range ((bp), #enum_name, 0, \
 305                                         (int)(enum_last) - 1)
 306
 307 /* Output the start of a record with TAG to output block OB.  */
 308
 309 static inline void
 310 streamer_write_record_start (struct output_block *ob, enum LTO_tags tag)
 311 {
 312   streamer_write_enum (ob->main_stream, LTO_tags, LTO_NUM_TAGS, tag);
 313 }
 314
 315 /* Return the next tag in the input block IB.  */
 316
 317 static inline enum LTO_tags
 318 streamer_read_record_start (struct lto_input_block *ib)
 319 {
 320   return streamer_read_enum (ib, LTO_tags, LTO_NUM_TAGS);
 321 }
 322
 323 #endif  /* GCC_DATA_STREAMER_H  */