gcc/gimple-streamer-in.c

   1 /* Routines for reading GIMPLE from a file stream.
   2
   3    Copyright (C) 2011-2015 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 "diagnostic.h"
  26 #include "alias.h"
  27 #include "backend.h"
  28 #include "tree.h"
  29 #include "gimple.h"
  30 #include "hard-reg-set.h"
  31 #include "ssa.h"
  32 #include "options.h"
  33 #include "fold-const.h"
  34 #include "internal-fn.h"
  35 #include "tree-eh.h"
  36 #include "gimple-iterator.h"
  37 #include "cgraph.h"
  38 #include "data-streamer.h"
  39 #include "tree-streamer.h"
  40 #include "gimple-streamer.h"
  41 #include "value-prof.h"
  42
  43 /* Read a PHI function for basic block BB in function FN.  DATA_IN is
  44    the file being read.  IB is the input block to use for reading.  */
  45
  46 static gphi *
  47 input_phi (struct lto_input_block *ib, basic_block bb, struct data_in *data_in,
  48            struct function *fn)
  49 {
  50   unsigned HOST_WIDE_INT ix;
  51   tree phi_result;
  52   int i, len;
  53   gphi *result;
  54
  55   ix = streamer_read_uhwi (ib);
  56   phi_result = (*SSANAMES (fn))[ix];
  57   len = EDGE_COUNT (bb->preds);
  58   result = create_phi_node (phi_result, bb);
  59
  60   /* We have to go through a lookup process here because the preds in the
  61      reconstructed graph are generally in a different order than they
  62      were in the original program.  */
  63   for (i = 0; i < len; i++)
  64     {
  65       tree def = stream_read_tree (ib, data_in);
  66       int src_index = streamer_read_uhwi (ib);
  67       bitpack_d bp = streamer_read_bitpack (ib);
  68       /* Do not cache a location - we do not have API to get pointer to the
  69          location in PHI statement and we may trigger reallocation.  */
  70       location_t arg_loc = stream_input_location_now (&bp, data_in);
  71       basic_block sbb = BASIC_BLOCK_FOR_FN (fn, src_index);
  72
  73       edge e = NULL;
  74       int j;
  75
  76       for (j = 0; j < len; j++)
  77         if (EDGE_PRED (bb, j)->src == sbb)
  78           {
  79             e = EDGE_PRED (bb, j);
  80             break;
  81           }
  82
  83       add_phi_arg (result, def, e, arg_loc);
  84     }
  85
  86   return result;
  87 }
  88
  89
  90 /* Read a statement with tag TAG in function FN from block IB using
  91    descriptors in DATA_IN.  */
  92
  93 static gimple
  94 input_gimple_stmt (struct lto_input_block *ib, struct data_in *data_in,
  95                    enum LTO_tags tag)
  96 {
  97   gimple stmt;
  98   enum gimple_code code;
  99   unsigned HOST_WIDE_INT num_ops;
 100   size_t i;
 101   struct bitpack_d bp;
 102   bool has_hist;
 103
 104   code = lto_tag_to_gimple_code (tag);
 105
 106   /* Read the tuple header.  */
 107   bp = streamer_read_bitpack (ib);
 108   num_ops = bp_unpack_var_len_unsigned (&bp);
 109   stmt = gimple_alloc (code, num_ops);
 110   stmt->no_warning = bp_unpack_value (&bp, 1);
 111   if (is_gimple_assign (stmt))
 112     stmt->nontemporal_move = bp_unpack_value (&bp, 1);
 113   stmt->has_volatile_ops = bp_unpack_value (&bp, 1);
 114   has_hist = bp_unpack_value (&bp, 1);
 115   stmt->subcode = bp_unpack_var_len_unsigned (&bp);
 116
 117   /* Read location information.  Caching here makes no sense until streamer
 118      cache can handle the following gimple_set_block.  */
 119   gimple_set_location (stmt, stream_input_location_now (&bp, data_in));
 120
 121   /* Read lexical block reference.  */
 122   gimple_set_block (stmt, stream_read_tree (ib, data_in));
 123
 124   /* Read in all the operands.  */
 125   switch (code)
 126     {
 127     case GIMPLE_RESX:
 128       gimple_resx_set_region (as_a <gresx *> (stmt),
 129                               streamer_read_hwi (ib));
 130       break;
 131
 132     case GIMPLE_EH_MUST_NOT_THROW:
 133       gimple_eh_must_not_throw_set_fndecl (
 134         as_a <geh_mnt *> (stmt),
 135         stream_read_tree (ib, data_in));
 136       break;
 137
 138     case GIMPLE_EH_DISPATCH:
 139       gimple_eh_dispatch_set_region (as_a <geh_dispatch *> (stmt),
 140                                      streamer_read_hwi (ib));
 141       break;
 142
 143     case GIMPLE_ASM:
 144       {
 145         /* FIXME lto.  Move most of this into a new gimple_asm_set_string().  */
 146         gasm *asm_stmt = as_a <gasm *> (stmt);
 147         tree str;
 148         asm_stmt->ni = streamer_read_uhwi (ib);
 149         asm_stmt->no = streamer_read_uhwi (ib);
 150         asm_stmt->nc = streamer_read_uhwi (ib);
 151         asm_stmt->nl = streamer_read_uhwi (ib);
 152         str = streamer_read_string_cst (data_in, ib);
 153         asm_stmt->string = TREE_STRING_POINTER (str);
 154       }
 155       /* Fallthru  */
 156
 157     case GIMPLE_ASSIGN:
 158     case GIMPLE_CALL:
 159     case GIMPLE_RETURN:
 160     case GIMPLE_SWITCH:
 161     case GIMPLE_LABEL:
 162     case GIMPLE_COND:
 163     case GIMPLE_GOTO:
 164     case GIMPLE_DEBUG:
 165       for (i = 0; i < num_ops; i++)
 166         {
 167           tree *opp, op = stream_read_tree (ib, data_in);
 168           gimple_set_op (stmt, i, op);
 169           if (!op)
 170             continue;
 171
 172           opp = gimple_op_ptr (stmt, i);
 173           if (TREE_CODE (*opp) == ADDR_EXPR)
 174             opp = &TREE_OPERAND (*opp, 0);
 175           while (handled_component_p (*opp))
 176             opp = &TREE_OPERAND (*opp, 0);
 177           /* At LTO output time we wrap all global decls in MEM_REFs to
 178              allow seamless replacement with prevailing decls.  Undo this
 179              here if the prevailing decl allows for this.
 180              ???  Maybe we should simply fold all stmts.  */
 181           if (TREE_CODE (*opp) == MEM_REF
 182               && TREE_CODE (TREE_OPERAND (*opp, 0)) == ADDR_EXPR
 183               && integer_zerop (TREE_OPERAND (*opp, 1))
 184               && (TREE_THIS_VOLATILE (*opp)
 185                   == TREE_THIS_VOLATILE
 186                        (TREE_OPERAND (TREE_OPERAND (*opp, 0), 0)))
 187               && !TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (TREE_OPERAND (*opp, 1)))
 188               && (TREE_TYPE (*opp)
 189                   == TREE_TYPE (TREE_TYPE (TREE_OPERAND (*opp, 1))))
 190               && (TREE_TYPE (*opp)
 191                   == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (*opp, 0), 0))))
 192             *opp = TREE_OPERAND (TREE_OPERAND (*opp, 0), 0);
 193         }
 194       if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 195         {
 196           if (gimple_call_internal_p (call_stmt))
 197             gimple_call_set_internal_fn
 198               (call_stmt, streamer_read_enum (ib, internal_fn, IFN_LAST));
 199           else
 200             gimple_call_set_fntype (call_stmt, stream_read_tree (ib, data_in));
 201         }
 202       break;
 203
 204     case GIMPLE_NOP:
 205     case GIMPLE_PREDICT:
 206       break;
 207
 208     case GIMPLE_TRANSACTION:
 209       gimple_transaction_set_label (as_a <gtransaction *> (stmt),
 210                                     stream_read_tree (ib, data_in));
 211       break;
 212
 213     default:
 214       internal_error ("bytecode stream: unknown GIMPLE statement tag %s",
 215                       lto_tag_name (tag));
 216     }
 217
 218   /* Update the properties of symbols, SSA names and labels associated
 219      with STMT.  */
 220   if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
 221     {
 222       tree lhs = gimple_get_lhs (stmt);
 223       if (lhs && TREE_CODE (lhs) == SSA_NAME)
 224         SSA_NAME_DEF_STMT (lhs) = stmt;
 225     }
 226   else if (code == GIMPLE_ASM)
 227     {
 228       gasm *asm_stmt = as_a <gasm *> (stmt);
 229       unsigned i;
 230
 231       for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
 232         {
 233           tree op = TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
 234           if (TREE_CODE (op) == SSA_NAME)
 235             SSA_NAME_DEF_STMT (op) = stmt;
 236         }
 237     }
 238
 239   /* Reset alias information.  */
 240   if (code == GIMPLE_CALL)
 241     gimple_call_reset_alias_info (as_a <gcall *> (stmt));
 242
 243   /* Mark the statement modified so its operand vectors can be filled in.  */
 244   gimple_set_modified (stmt, true);
 245   if (has_hist)
 246     stream_in_histogram_value (ib, stmt);
 247
 248   return stmt;
 249 }
 250
 251
 252 /* Read a basic block with tag TAG from DATA_IN using input block IB.
 253    FN is the function being processed.  */
 254
 255 void
 256 input_bb (struct lto_input_block *ib, enum LTO_tags tag,
 257           struct data_in *data_in, struct function *fn,
 258           int count_materialization_scale)
 259 {
 260   unsigned int index;
 261   basic_block bb;
 262   gimple_stmt_iterator bsi;
 263
 264   /* This routine assumes that CFUN is set to FN, as it needs to call
 265      basic GIMPLE routines that use CFUN.  */
 266   gcc_assert (cfun == fn);
 267
 268   index = streamer_read_uhwi (ib);
 269   bb = BASIC_BLOCK_FOR_FN (fn, index);
 270
 271   bb->count = apply_scale (streamer_read_gcov_count (ib),
 272                            count_materialization_scale);
 273   bb->frequency = streamer_read_hwi (ib);
 274   bb->flags = streamer_read_hwi (ib);
 275
 276   /* LTO_bb1 has statements.  LTO_bb0 does not.  */
 277   if (tag == LTO_bb0)
 278     return;
 279
 280   bsi = gsi_start_bb (bb);
 281   tag = streamer_read_record_start (ib);
 282   while (tag)
 283     {
 284       gimple stmt = input_gimple_stmt (ib, data_in, tag);
 285       gsi_insert_after (&bsi, stmt, GSI_NEW_STMT);
 286
 287       /* After the statement, expect a 0 delimiter or the EH region
 288          that the previous statement belongs to.  */
 289       tag = streamer_read_record_start (ib);
 290       lto_tag_check_set (tag, 2, LTO_eh_region, LTO_null);
 291
 292       if (tag == LTO_eh_region)
 293         {
 294           HOST_WIDE_INT region = streamer_read_hwi (ib);
 295           gcc_assert (region == (int) region);
 296           add_stmt_to_eh_lp (stmt, region);
 297         }
 298
 299       tag = streamer_read_record_start (ib);
 300     }
 301
 302   tag = streamer_read_record_start (ib);
 303   while (tag)
 304     {
 305       input_phi (ib, bb, data_in, fn);
 306       tag = streamer_read_record_start (ib);
 307     }
 308 }