gcc/lto-section-out.c

   1 /* Functions for writing LTO sections.
   2
   3    Copyright (C) 2009-2021 Free Software Foundation, Inc.
   4    Contributed by Kenneth Zadeck <zadeck@naturalbridge.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 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "backend.h"
  26 #include "rtl.h"
  27 #include "tree.h"
  28 #include "gimple.h"
  29 #include "cgraph.h"
  30 #include "data-streamer.h"
  31 #include "langhooks.h"
  32 #include "lto-compress.h"
  33 #include "print-tree.h"
  34
  35 static vec<lto_out_decl_state_ptr> decl_state_stack;
  36
  37 /* List of out decl states used by functions.  We use this to
  38    generate the decl directory later. */
  39
  40 vec<lto_out_decl_state_ptr> lto_function_decl_states;
  41
  42
  43 /*****************************************************************************
  44    Output routines shared by all of the serialization passes.
  45 *****************************************************************************/
  46
  47
  48 /* Flush compressed stream data function, sends NUM_CHARS from CHARS
  49    to the append lang hook, OPAQUE is currently always NULL.  */
  50
  51 static void
  52 lto_append_data (const char *chars, unsigned int num_chars, void *opaque)
  53 {
  54   gcc_assert (opaque == NULL);
  55   lang_hooks.lto.append_data (chars, num_chars, opaque);
  56 }
  57
  58 /* Pointer to the current compression stream.  */
  59
  60 static struct lto_compression_stream *compression_stream = NULL;
  61
  62 /* Begin a new output section named NAME. If COMPRESS is true, zlib compress
  63    the section. */
  64
  65 void
  66 lto_begin_section (const char *name, bool compress)
  67 {
  68   lang_hooks.lto.begin_section (name);
  69
  70   if (streamer_dump_file)
  71     {
  72       if (flag_dump_unnumbered || flag_dump_noaddr)
  73           fprintf (streamer_dump_file, "Creating %ssection\n",
  74                    compress ? "compressed " : "");
  75         else
  76           fprintf (streamer_dump_file, "Creating %ssection %s\n",
  77                    compress ? "compressed " : "", name);
  78     }
  79   gcc_assert (compression_stream == NULL);
  80   if (compress)
  81     compression_stream = lto_start_compression (lto_append_data, NULL);
  82 }
  83
  84
  85 /* End the current output section.  */
  86
  87 void
  88 lto_end_section (void)
  89 {
  90   if (compression_stream)
  91     {
  92       lto_end_compression (compression_stream);
  93       compression_stream = NULL;
  94     }
  95   lang_hooks.lto.end_section ();
  96 }
  97
  98 /* Write SIZE bytes starting at DATA to the assembler.  */
  99
 100 void
 101 lto_write_data (const void *data, unsigned int size)
 102 {
 103   if (compression_stream)
 104     lto_compress_block (compression_stream, (const char *)data, size);
 105   else
 106     lang_hooks.lto.append_data ((const char *)data, size, NULL);
 107 }
 108
 109 /* Write SIZE bytes starting at DATA to the assembler.  */
 110
 111 void
 112 lto_write_raw_data (const void *data, unsigned int size)
 113 {
 114   lang_hooks.lto.append_data ((const char *)data, size, NULL);
 115 }
 116
 117 /* Write all of the chars in OBS to the assembler.  Recycle the blocks
 118    in obs as this is being done.  */
 119
 120 void
 121 lto_write_stream (struct lto_output_stream *obs)
 122 {
 123   unsigned int block_size = 1024;
 124   struct lto_char_ptr_base *block;
 125   struct lto_char_ptr_base *next_block;
 126   if (!obs->first_block)
 127     return;
 128
 129   for (block = obs->first_block; block; block = next_block)
 130     {
 131       const char *base = ((char *)block) + sizeof (struct lto_char_ptr_base);
 132       unsigned int num_chars = block_size - sizeof (struct lto_char_ptr_base);
 133
 134       /* If this is not the last block, it is full.  If it is the last
 135          block, left_in_block indicates how many chars are unoccupied in
 136          this block; subtract from num_chars to obtain occupancy.  */
 137       next_block = (struct lto_char_ptr_base *) block->ptr;
 138       if (!next_block)
 139         num_chars -= obs->left_in_block;
 140
 141       if (compression_stream)
 142         lto_compress_block (compression_stream, base, num_chars);
 143       else
 144         lang_hooks.lto.append_data (base, num_chars, block);
 145       free (block);
 146       block_size *= 2;
 147     }
 148 }
 149
 150 /* Create the output block and return it.  */
 151
 152 struct lto_simple_output_block *
 153 lto_create_simple_output_block (enum lto_section_type section_type)
 154 {
 155   struct lto_simple_output_block *ob
 156     = ((struct lto_simple_output_block *)
 157        xcalloc (1, sizeof (struct lto_simple_output_block)));
 158
 159   ob->section_type = section_type;
 160   ob->decl_state = lto_get_out_decl_state ();
 161   ob->main_stream = ((struct lto_output_stream *)
 162                      xcalloc (1, sizeof (struct lto_output_stream)));
 163
 164   return ob;
 165 }
 166
 167
 168 /* Produce a simple section for one of the ipa passes.  */
 169
 170 void
 171 lto_destroy_simple_output_block (struct lto_simple_output_block *ob)
 172 {
 173   char *section_name;
 174   struct lto_simple_header header;
 175
 176   section_name = lto_get_section_name (ob->section_type, NULL, 0, NULL);
 177   lto_begin_section (section_name, !flag_wpa);
 178   free (section_name);
 179
 180   /* Write the header which says how to decode the pieces of the
 181      t.  */
 182   memset (&header, 0, sizeof (struct lto_simple_header));
 183   header.main_size = ob->main_stream->total_size;
 184   lto_write_data (&header, sizeof header);
 185
 186   lto_write_stream (ob->main_stream);
 187
 188   /* Put back the assembly section that was there before we started
 189      writing lto info.  */
 190   lto_end_section ();
 191
 192   free (ob->main_stream);
 193   free (ob);
 194 }
 195
 196
 197 /* Return a new lto_out_decl_state. */
 198
 199 struct lto_out_decl_state *
 200 lto_new_out_decl_state (void)
 201 {
 202   struct lto_out_decl_state *state = XCNEW (struct lto_out_decl_state);
 203   int i;
 204
 205   for (i = 0; i < LTO_N_DECL_STREAMS; i++)
 206     lto_init_tree_ref_encoder (&state->streams[i]);
 207
 208   /* At WPA time we do not compress sections by default.  */
 209   state->compressed = !flag_wpa;
 210
 211   return state;
 212 }
 213
 214
 215 /* Delete STATE and components.  */
 216
 217 void
 218 lto_delete_out_decl_state (struct lto_out_decl_state *state)
 219 {
 220   int i;
 221
 222   for (i = 0; i < LTO_N_DECL_STREAMS; i++)
 223     lto_destroy_tree_ref_encoder (&state->streams[i]);
 224
 225   free (state);
 226 }
 227
 228
 229 /* Get the currently used lto_out_decl_state structure. */
 230
 231 struct lto_out_decl_state *
 232 lto_get_out_decl_state (void)
 233 {
 234   return decl_state_stack.last ();
 235 }
 236
 237 /* Push STATE to top of out decl stack. */
 238
 239 void
 240 lto_push_out_decl_state (struct lto_out_decl_state *state)
 241 {
 242   decl_state_stack.safe_push (state);
 243 }
 244
 245 /* Pop the currently used out-decl state from top of stack. */
 246
 247 struct lto_out_decl_state *
 248 lto_pop_out_decl_state (void)
 249 {
 250   return decl_state_stack.pop ();
 251 }
 252
 253 /* Record STATE after it has been used in serializing the body of
 254    FN_DECL.  STATE should no longer be used by the caller.  The ownership
 255    of it is taken over from this point.  */
 256
 257 void
 258 lto_record_function_out_decl_state (tree fn_decl,
 259                                     struct lto_out_decl_state *state)
 260 {
 261   int i;
 262
 263   /* Strip all hash tables to save some memory. */
 264   for (i = 0; i < LTO_N_DECL_STREAMS; i++)
 265     if (state->streams[i].tree_hash_table)
 266       {
 267         delete state->streams[i].tree_hash_table;
 268         state->streams[i].tree_hash_table = NULL;
 269       }
 270   state->fn_decl = fn_decl;
 271   lto_function_decl_states.safe_push (state);
 272 }