gcc/gimple-streamer-in.c

   1 /* Routines for reading GIMPLE from a file stream.
   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 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "backend.h"
  26 #include "tree.h"
  27 #include "gimple.h"
  28 #include "ssa.h"
  29 #include "gimple-streamer.h"
  30 #include "tree-eh.h"
  31 #include "gimple-iterator.h"
  32 #include "cgraph.h"
  33 #include "value-prof.h"
  34
  35 /* Read a PHI function for basic block BB in function FN.  DATA_IN is
  36    the file being read.  IB is the input block to use for reading.  */
  37
  38 static gphi *
  39 input_phi (struct lto_input_block *ib, basic_block bb, struct data_in *data_in,
  40            struct function *fn)
  41 {
  42   unsigned HOST_WIDE_INT ix;
  43   tree phi_result;
  44   int i, len;
  45   gphi *result;
  46
  47   ix = streamer_read_uhwi (ib);
  48   phi_result = (*SSANAMES (fn))[ix];
  49   len = EDGE_COUNT (bb->preds);
  50   result = create_phi_node (phi_result, bb);
  51
  52   /* We have to go through a lookup process here because the preds in the
  53      reconstructed graph are generally in a different order than they
  54      were in the original program.  */
  55   for (i = 0; i < len; i++)
  56     {
  57       tree def = stream_read_tree (ib, data_in);
  58       int src_index = streamer_read_uhwi (ib);
  59       bitpack_d bp = streamer_read_bitpack (ib);
  60       /* Do not cache a location - we do not have API to get pointer to the
  61          location in PHI statement and we may trigger reallocation.  */
  62       location_t arg_loc = stream_input_location_now (&bp, data_in);
  63       basic_block sbb = BASIC_BLOCK_FOR_FN (fn, src_index);
  64
  65       edge e = NULL;
  66       int j;
  67
  68       for (j = 0; j < len; j++)
  69         if (EDGE_PRED (bb, j)->src == sbb)
  70           {
  71             e = EDGE_PRED (bb, j);
  72             break;
  73           }
  74
  75       add_phi_arg (result, def, e, arg_loc);
  76     }
  77
  78   return result;
  79 }
  80
  81
  82 /* Read a statement with tag TAG in function FN from block IB using
  83    descriptors in DATA_IN.  */
  84
  85 static gimple *
  86 input_gimple_stmt (struct lto_input_block *ib, struct data_in *data_in,
  87                    enum LTO_tags tag)
  88 {
  89   gimple *stmt;
  90   enum gimple_code code;
  91   unsigned HOST_WIDE_INT num_ops;
  92   size_t i;
  93   struct bitpack_d bp;
  94   bool has_hist;
  95
  96   code = lto_tag_to_gimple_code (tag);
  97
  98   /* Read the tuple header.  */
  99   bp = streamer_read_bitpack (ib);
 100   num_ops = bp_unpack_var_len_unsigned (&bp);
 101   stmt = gimple_alloc (code, num_ops);
 102   stmt->no_warning = bp_unpack_value (&bp, 1);
 103   if (is_gimple_assign (stmt))
 104     stmt->nontemporal_move = bp_unpack_value (&bp, 1);
 105   stmt->has_volatile_ops = bp_unpack_value (&bp, 1);
 106   has_hist = bp_unpack_value (&bp, 1);
 107   stmt->subcode = bp_unpack_var_len_unsigned (&bp);
 108
 109   /* Read location information.  Caching here makes no sense until streamer
 110      cache can handle the following gimple_set_block.  */
 111   gimple_set_location (stmt, stream_input_location_now (&bp, data_in));
 112
 113   /* Read lexical block reference.  */
 114   gimple_set_block (stmt, stream_read_tree (ib, data_in));
 115
 116   /* Read in all the operands.  */
 117   switch (code)
 118     {
 119     case GIMPLE_RESX:
 120       gimple_resx_set_region (as_a <gresx *> (stmt),
 121                               streamer_read_hwi (ib));
 122       break;
 123
 124     case GIMPLE_EH_MUST_NOT_THROW:
 125       gimple_eh_must_not_throw_set_fndecl (
 126         as_a <geh_mnt *> (stmt),
 127         stream_read_tree (ib, data_in));
 128       break;
 129
 130     case GIMPLE_EH_DISPATCH:
 131       gimple_eh_dispatch_set_region (as_a <geh_dispatch *> (stmt),
 132                                      streamer_read_hwi (ib));
 133       break;
 134
 135     case GIMPLE_ASM:
 136       {
 137         /* FIXME lto.  Move most of this into a new gimple_asm_set_string().  */
 138         gasm *asm_stmt = as_a <gasm *> (stmt);
 139         tree str;
 140         asm_stmt->ni = streamer_read_uhwi (ib);
 141         asm_stmt->no = streamer_read_uhwi (ib);
 142         asm_stmt->nc = streamer_read_uhwi (ib);
 143         asm_stmt->nl = streamer_read_uhwi (ib);
 144         str = streamer_read_string_cst (data_in, ib);
 145         asm_stmt->string = TREE_STRING_POINTER (str);
 146       }
 147       /* Fallthru  */
 148
 149     case GIMPLE_ASSIGN:
 150     case GIMPLE_CALL:
 151     case GIMPLE_RETURN:
 152     case GIMPLE_SWITCH:
 153     case GIMPLE_LABEL:
 154     case GIMPLE_COND:
 155     case GIMPLE_GOTO:
 156     case GIMPLE_DEBUG:
 157       for (i = 0; i < num_ops; i++)
 158         {
 159           tree *opp, op = stream_read_tree (ib, data_in);
 160           gimple_set_op (stmt, i, op);
 161           if (!op)
 162             continue;
 163
 164           opp = gimple_op_ptr (stmt, i);
 165           if (TREE_CODE (*opp) == ADDR_EXPR)
 166             opp = &TREE_OPERAND (*opp, 0);
 167           while (handled_component_p (*opp))
 168             opp = &TREE_OPERAND (*opp, 0);
 169           /* At LTO output time we wrap all global decls in MEM_REFs to
 170              allow seamless replacement with prevailing decls.  Undo this
 171              here if the prevailing decl allows for this.
 172              ???  Maybe we should simply fold all stmts.  */
 173           if (TREE_CODE (*opp) == MEM_REF
 174               && TREE_CODE (TREE_OPERAND (*opp, 0)) == ADDR_EXPR
 175               && integer_zerop (TREE_OPERAND (*opp, 1))
 176               && (TREE_THIS_VOLATILE (*opp)
 177                   == TREE_THIS_VOLATILE
 178                        (TREE_OPERAND (TREE_OPERAND (*opp, 0), 0)))
 179               && !TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (TREE_OPERAND (*opp, 1)))
 180               && (TREE_TYPE (*opp)
 181                   == TREE_TYPE (TREE_TYPE (TREE_OPERAND (*opp, 1))))
 182               && (TREE_TYPE (*opp)
 183                   == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (*opp, 0), 0))))
 184             *opp = TREE_OPERAND (TREE_OPERAND (*opp, 0), 0);
 185         }
 186       if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 187         {
 188           if (gimple_call_internal_p (call_stmt))
 189             gimple_call_set_internal_fn
 190               (call_stmt, streamer_read_enum (ib, internal_fn, IFN_LAST));
 191           else
 192             gimple_call_set_fntype (call_stmt, stream_read_tree (ib, data_in));
 193         }
 194       break;
 195
 196     case GIMPLE_NOP:
 197     case GIMPLE_PREDICT:
 198       break;
 199
 200     case GIMPLE_TRANSACTION:
 201       gimple_transaction_set_label_norm (as_a <gtransaction *> (stmt),
 202                                          stream_read_tree (ib, data_in));
 203       gimple_transaction_set_label_uninst (as_a <gtransaction *> (stmt),
 204                                            stream_read_tree (ib, data_in));
 205       gimple_transaction_set_label_over (as_a <gtransaction *> (stmt),
 206                                          stream_read_tree (ib, data_in));
 207       break;
 208
 209     default:
 210       internal_error ("bytecode stream: unknown GIMPLE statement tag %s",
 211                       lto_tag_name (tag));
 212     }
 213
 214   /* Update the properties of symbols, SSA names and labels associated
 215      with STMT.  */
 216   if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
 217     {
 218       tree lhs = gimple_get_lhs (stmt);
 219       if (lhs && TREE_CODE (lhs) == SSA_NAME)
 220         SSA_NAME_DEF_STMT (lhs) = stmt;
 221     }
 222   else if (code == GIMPLE_ASM)
 223     {
 224       gasm *asm_stmt = as_a <gasm *> (stmt);
 225       unsigned i;
 226
 227       for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
 228         {
 229           tree op = TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
 230           if (TREE_CODE (op) == SSA_NAME)
 231             SSA_NAME_DEF_STMT (op) = stmt;
 232         }
 233     }
 234
 235   /* Reset alias information.  */
 236   if (code == GIMPLE_CALL)
 237     gimple_call_reset_alias_info (as_a <gcall *> (stmt));
 238
 239   /* Mark the statement modified so its operand vectors can be filled in.  */
 240   gimple_set_modified (stmt, true);
 241   if (has_hist)
 242     stream_in_histogram_value (ib, stmt);
 243
 244   return stmt;
 245 }
 246
 247
 248 /* Read a basic block with tag TAG from DATA_IN using input block IB.
 249    FN is the function being processed.  */
 250
 251 void
 252 input_bb (struct lto_input_block *ib, enum LTO_tags tag,
 253           struct data_in *data_in, struct function *fn,
 254           int count_materialization_scale)
 255 {
 256   unsigned int index;
 257   basic_block bb;
 258   gimple_stmt_iterator bsi;
 259
 260   /* This routine assumes that CFUN is set to FN, as it needs to call
 261      basic GIMPLE routines that use CFUN.  */
 262   gcc_assert (cfun == fn);
 263
 264   index = streamer_read_uhwi (ib);
 265   bb = BASIC_BLOCK_FOR_FN (fn, index);
 266
 267   bb->count = profile_count::stream_in (ib);
 268   if (count_materialization_scale != REG_BR_PROB_BASE
 269       && bb->count.ipa ().nonzero_p ())
 270     bb->count
 271       = bb->count.apply_scale (count_materialization_scale, REG_BR_PROB_BASE);
 272   bb->flags = streamer_read_hwi (ib);
 273
 274   /* LTO_bb1 has statements.  LTO_bb0 does not.  */
 275   if (tag == LTO_bb0)
 276     return;
 277
 278   bsi = gsi_start_bb (bb);
 279   tag = streamer_read_record_start (ib);
 280   while (tag)
 281     {
 282       gimple *stmt = input_gimple_stmt (ib, data_in, tag);
 283       gsi_insert_after (&bsi, stmt, GSI_NEW_STMT);
 284
 285       /* After the statement, expect a 0 delimiter or the EH region
 286          that the previous statement belongs to.  */
 287       tag = streamer_read_record_start (ib);
 288       lto_tag_check_set (tag, 2, LTO_eh_region, LTO_null);
 289
 290       if (tag == LTO_eh_region)
 291         {
 292           HOST_WIDE_INT region = streamer_read_hwi (ib);
 293           gcc_assert (region == (int) region);
 294           add_stmt_to_eh_lp (stmt, region);
 295         }
 296
 297       tag = streamer_read_record_start (ib);
 298     }
 299
 300   tag = streamer_read_record_start (ib);
 301   while (tag)
 302     {
 303       input_phi (ib, bb, data_in, fn);
 304       tag = streamer_read_record_start (ib);
 305     }
 306 }