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 /* In data-streamer.c  */
  48 void bp_pack_var_len_unsigned (struct bitpack_d *, unsigned HOST_WIDE_INT);
  49 void bp_pack_var_len_int (struct bitpack_d *, HOST_WIDE_INT);
  50 unsigned HOST_WIDE_INT bp_unpack_var_len_unsigned (struct bitpack_d *);
  51 HOST_WIDE_INT bp_unpack_var_len_int (struct bitpack_d *);
  52
  53 /* In data-streamer-out.c  */
  54 void streamer_write_zero (struct output_block *);
  55 void streamer_write_uhwi (struct output_block *, unsigned HOST_WIDE_INT);
  56 void streamer_write_hwi (struct output_block *, HOST_WIDE_INT);
  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 unsigned streamer_string_index (struct output_block *, const char *,
  61                                 unsigned int, bool);
  62 void streamer_write_string_with_length (struct output_block *,
  63                                         struct lto_output_stream *,
  64                                         const char *, unsigned int, bool);
  65 void bp_pack_string_with_length (struct output_block *, struct bitpack_d *,
  66                                  const char *, unsigned int, bool);
  67 void bp_pack_string (struct output_block *, struct bitpack_d *,
  68                      const char *, bool);
  69 void streamer_write_uhwi_stream (struct lto_output_stream *,
  70                                  unsigned HOST_WIDE_INT);
  71 void streamer_write_hwi_stream (struct lto_output_stream *, HOST_WIDE_INT);
  72 void streamer_write_gcov_count_stream (struct lto_output_stream *, gcov_type);
  73
  74 /* In data-streamer-in.c  */
  75 const char *string_for_index (struct data_in *, unsigned int, unsigned int *);
  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
  87 /* Returns a new bit-packing context for bit-packing into S.  */
  88 static inline struct bitpack_d
  89 bitpack_create (struct lto_output_stream *s)
  90 {
  91   struct bitpack_d bp;
  92   bp.pos = 0;
  93   bp.word = 0;
  94   bp.stream = (void *)s;
  95   return bp;
  96 }
  97
  98 /* Pack the NBITS bit sized value VAL into the bit-packing context BP.  */
  99 static inline void
 100 bp_pack_value (struct bitpack_d *bp, bitpack_word_t val, unsigned nbits)
 101 {
 102   bitpack_word_t word = bp->word;
 103   int pos = bp->pos;
 104
 105   /* Verify that VAL fits in the NBITS.  */
 106   gcc_checking_assert (nbits == BITS_PER_BITPACK_WORD
 107                        || !(val & ~(((bitpack_word_t)1<<nbits)-1)));
 108
 109   /* If val does not fit into the current bitpack word switch to the
 110      next one.  */
 111   if (pos + nbits > BITS_PER_BITPACK_WORD)
 112     {
 113       streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 114                                   word);
 115       word = val;
 116       pos = nbits;
 117     }
 118   else
 119     {
 120       word |= val << pos;
 121       pos += nbits;
 122     }
 123   bp->word = word;
 124   bp->pos = pos;
 125 }
 126
 127 /* Finishes bit-packing of BP.  */
 128 static inline void
 129 streamer_write_bitpack (struct bitpack_d *bp)
 130 {
 131   streamer_write_uhwi_stream ((struct lto_output_stream *) bp->stream,
 132                               bp->word);
 133   bp->word = 0;
 134   bp->pos = 0;
 135 }
 136
 137 /* Returns a new bit-packing context for bit-unpacking from IB.  */
 138 static inline struct bitpack_d
 139 streamer_read_bitpack (struct lto_input_block *ib)
 140 {
 141   struct bitpack_d bp;
 142   bp.word = streamer_read_uhwi (ib);
 143   bp.pos = 0;
 144   bp.stream = (void *)ib;
 145   return bp;
 146 }
 147
 148 /* Unpacks NBITS bits from the bit-packing context BP and returns them.  */
 149 static inline bitpack_word_t
 150 bp_unpack_value (struct bitpack_d *bp, unsigned nbits)
 151 {
 152   bitpack_word_t mask, val;
 153   int pos = bp->pos;
 154
 155   mask = (nbits == BITS_PER_BITPACK_WORD
 156           ? (bitpack_word_t) -1
 157           : ((bitpack_word_t) 1 << nbits) - 1);
 158
 159   /* If there are not continuous nbits in the current bitpack word
 160      switch to the next one.  */
 161   if (pos + nbits > BITS_PER_BITPACK_WORD)
 162     {
 163       bp->word = val
 164         = streamer_read_uhwi ((struct lto_input_block *)bp->stream);
 165       bp->pos = nbits;
 166       return val & mask;
 167     }
 168   val = bp->word;
 169   val >>= pos;
 170   bp->pos = pos + nbits;
 171
 172   return val & mask;
 173 }
 174
 175
 176 /* Write a character to the output block.  */
 177
 178 static inline void
 179 streamer_write_char_stream (struct lto_output_stream *obs, char c)
 180 {
 181   /* No space left.  */
 182   if (obs->left_in_block == 0)
 183     lto_append_block (obs);
 184
 185   /* Write the actual character.  */
 186   *obs->current_pointer = c;
 187   obs->current_pointer++;
 188   obs->total_size++;
 189   obs->left_in_block--;
 190 }
 191
 192
 193 /* Read byte from the input block.  */
 194
 195 static inline unsigned char
 196 streamer_read_uchar (struct lto_input_block *ib)
 197 {
 198   if (ib->p >= ib->len)
 199     lto_section_overrun (ib);
 200   return (ib->data[ib->p++]);
 201 }
 202
 203 /* Output VAL into OBS and verify it is in range MIN...MAX that is supposed
 204    to be compile time constant.
 205    Be host independent, limit range to 31bits.  */
 206
 207 static inline void
 208 streamer_write_hwi_in_range (struct lto_output_stream *obs,
 209                                   HOST_WIDE_INT min,
 210                                   HOST_WIDE_INT max,
 211                                   HOST_WIDE_INT val)
 212 {
 213   HOST_WIDE_INT range = max - min;
 214
 215   gcc_checking_assert (val >= min && val <= max && range > 0
 216                        && range < 0x7fffffff);
 217
 218   val -= min;
 219   streamer_write_uhwi_stream (obs, (unsigned HOST_WIDE_INT) val);
 220 }
 221
 222 /* Input VAL into OBS and verify it is in range MIN...MAX that is supposed
 223    to be compile time constant.  PURPOSE is used for error reporting.  */
 224
 225 static inline HOST_WIDE_INT
 226 streamer_read_hwi_in_range (struct lto_input_block *ib,
 227                                  const char *purpose,
 228                                  HOST_WIDE_INT min,
 229                                  HOST_WIDE_INT max)
 230 {
 231   HOST_WIDE_INT range = max - min;
 232   unsigned HOST_WIDE_INT uval = streamer_read_uhwi (ib);
 233
 234   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 235
 236   HOST_WIDE_INT val = (HOST_WIDE_INT) (uval + (unsigned HOST_WIDE_INT) min);
 237   if (val < min || val > max)
 238     lto_value_range_error (purpose, val, min, max);
 239   return val;
 240 }
 241
 242 /* Output VAL into BP and verify it is in range MIN...MAX that is supposed
 243    to be compile time constant.
 244    Be host independent, limit range to 31bits.  */
 245
 246 static inline void
 247 bp_pack_int_in_range (struct bitpack_d *bp,
 248                       HOST_WIDE_INT min,
 249                       HOST_WIDE_INT max,
 250                       HOST_WIDE_INT val)
 251 {
 252   HOST_WIDE_INT range = max - min;
 253   int nbits = floor_log2 (range) + 1;
 254
 255   gcc_checking_assert (val >= min && val <= max && range > 0
 256                        && range < 0x7fffffff);
 257
 258   val -= min;
 259   bp_pack_value (bp, val, nbits);
 260 }
 261
 262 /* Input VAL into BP and verify it is in range MIN...MAX that is supposed
 263    to be compile time constant.  PURPOSE is used for error reporting.  */
 264
 265 static inline HOST_WIDE_INT
 266 bp_unpack_int_in_range (struct bitpack_d *bp,
 267                         const char *purpose,
 268                         HOST_WIDE_INT min,
 269                         HOST_WIDE_INT max)
 270 {
 271   HOST_WIDE_INT range = max - min;
 272   int nbits = floor_log2 (range) + 1;
 273   HOST_WIDE_INT val = bp_unpack_value (bp, nbits);
 274
 275   gcc_checking_assert (range > 0 && range < 0x7fffffff);
 276
 277   if (val < min || val > max)
 278     lto_value_range_error (purpose, val, min, max);
 279   return val;
 280 }
 281
 282 /* Output VAL of type "enum enum_name" into OBS.
 283    Assume range 0...ENUM_LAST - 1.  */
 284 #define streamer_write_enum(obs,enum_name,enum_last,val) \
 285   streamer_write_hwi_in_range ((obs), 0, (int)(enum_last) - 1, (int)(val))
 286
 287 /* Input enum of type "enum enum_name" from IB.
 288    Assume range 0...ENUM_LAST - 1.  */
 289 #define streamer_read_enum(ib,enum_name,enum_last) \
 290   (enum enum_name)streamer_read_hwi_in_range ((ib), #enum_name, 0, \
 291                                               (int)(enum_last) - 1)
 292
 293 /* Output VAL of type "enum enum_name" into BP.
 294    Assume range 0...ENUM_LAST - 1.  */
 295 #define bp_pack_enum(bp,enum_name,enum_last,val) \
 296   bp_pack_int_in_range ((bp), 0, (int)(enum_last) - 1, (int)(val))
 297
 298 /* Input enum of type "enum enum_name" from BP.
 299    Assume range 0...ENUM_LAST - 1.  */
 300 #define bp_unpack_enum(bp,enum_name,enum_last) \
 301   (enum enum_name)bp_unpack_int_in_range ((bp), #enum_name, 0, \
 302                                         (int)(enum_last) - 1)
 303
 304 /* Output the start of a record with TAG to output block OB.  */
 305
 306 static inline void
 307 streamer_write_record_start (struct output_block *ob, enum LTO_tags tag)
 308 {
 309   streamer_write_enum (ob->main_stream, LTO_tags, LTO_NUM_TAGS, tag);
 310 }
 311
 312 /* Return the next tag in the input block IB.  */
 313
 314 static inline enum LTO_tags
 315 streamer_read_record_start (struct lto_input_block *ib)
 316 {
 317   return streamer_read_enum (ib, LTO_tags, LTO_NUM_TAGS);
 318 }
 319
 320 #endif  /* GCC_DATA_STREAMER_H  */