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 "symtab.h"
  28 #include "options.h"
  29 #include "tree.h"
  30 #include "fold-const.h"
  31 #include "predict.h"
  32 #include "tm.h"
  33 #include "hard-reg-set.h"
  34 #include "function.h"
  35 #include "dominance.h"
  36 #include "cfg.h"
  37 #include "basic-block.h"
  38 #include "tree-ssa-alias.h"
  39 #include "internal-fn.h"
  40 #include "tree-eh.h"
  41 #include "gimple-expr.h"
  42 #include "gimple.h"
  43 #include "gimple-iterator.h"
  44 #include "gimple-ssa.h"
  45 #include "tree-phinodes.h"
  46 #include "stringpool.h"
  47 #include "tree-ssanames.h"
  48 #include "cgraph.h"
  49 #include "data-streamer.h"
  50 #include "tree-streamer.h"
  51 #include "gimple-streamer.h"
  52 #include "value-prof.h"
  53
  54 /* Read a PHI function for basic block BB in function FN.  DATA_IN is
  55    the file being read.  IB is the input block to use for reading.  */
  56
  57 static gphi *
  58 input_phi (struct lto_input_block *ib, basic_block bb, struct data_in *data_in,
  59            struct function *fn)
  60 {
  61   unsigned HOST_WIDE_INT ix;
  62   tree phi_result;
  63   int i, len;
  64   gphi *result;
  65
  66   ix = streamer_read_uhwi (ib);
  67   phi_result = (*SSANAMES (fn))[ix];
  68   len = EDGE_COUNT (bb->preds);
  69   result = create_phi_node (phi_result, bb);
  70
  71   /* We have to go through a lookup process here because the preds in the
  72      reconstructed graph are generally in a different order than they
  73      were in the original program.  */
  74   for (i = 0; i < len; i++)
  75     {
  76       tree def = stream_read_tree (ib, data_in);
  77       int src_index = streamer_read_uhwi (ib);
  78       bitpack_d bp = streamer_read_bitpack (ib);
  79       /* Do not cache a location - we do not have API to get pointer to the
  80          location in PHI statement and we may trigger reallocation.  */
  81       location_t arg_loc = stream_input_location_now (&bp, data_in);
  82       basic_block sbb = BASIC_BLOCK_FOR_FN (fn, src_index);
  83
  84       edge e = NULL;
  85       int j;
  86
  87       for (j = 0; j < len; j++)
  88         if (EDGE_PRED (bb, j)->src == sbb)
  89           {
  90             e = EDGE_PRED (bb, j);
  91             break;
  92           }
  93
  94       add_phi_arg (result, def, e, arg_loc);
  95     }
  96
  97   return result;
  98 }
  99
 100
 101 /* Read a statement with tag TAG in function FN from block IB using
 102    descriptors in DATA_IN.  */
 103
 104 static gimple
 105 input_gimple_stmt (struct lto_input_block *ib, struct data_in *data_in,
 106                    enum LTO_tags tag)
 107 {
 108   gimple stmt;
 109   enum gimple_code code;
 110   unsigned HOST_WIDE_INT num_ops;
 111   size_t i;
 112   struct bitpack_d bp;
 113   bool has_hist;
 114
 115   code = lto_tag_to_gimple_code (tag);
 116
 117   /* Read the tuple header.  */
 118   bp = streamer_read_bitpack (ib);
 119   num_ops = bp_unpack_var_len_unsigned (&bp);
 120   stmt = gimple_alloc (code, num_ops);
 121   stmt->no_warning = bp_unpack_value (&bp, 1);
 122   if (is_gimple_assign (stmt))
 123     stmt->nontemporal_move = bp_unpack_value (&bp, 1);
 124   stmt->has_volatile_ops = bp_unpack_value (&bp, 1);
 125   has_hist = bp_unpack_value (&bp, 1);
 126   stmt->subcode = bp_unpack_var_len_unsigned (&bp);
 127
 128   /* Read location information.  Caching here makes no sense until streamer
 129      cache can handle the following gimple_set_block.  */
 130   gimple_set_location (stmt, stream_input_location_now (&bp, data_in));
 131
 132   /* Read lexical block reference.  */
 133   gimple_set_block (stmt, stream_read_tree (ib, data_in));
 134
 135   /* Read in all the operands.  */
 136   switch (code)
 137     {
 138     case GIMPLE_RESX:
 139       gimple_resx_set_region (as_a <gresx *> (stmt),
 140                               streamer_read_hwi (ib));
 141       break;
 142
 143     case GIMPLE_EH_MUST_NOT_THROW:
 144       gimple_eh_must_not_throw_set_fndecl (
 145         as_a <geh_mnt *> (stmt),
 146         stream_read_tree (ib, data_in));
 147       break;
 148
 149     case GIMPLE_EH_DISPATCH:
 150       gimple_eh_dispatch_set_region (as_a <geh_dispatch *> (stmt),
 151                                      streamer_read_hwi (ib));
 152       break;
 153
 154     case GIMPLE_ASM:
 155       {
 156         /* FIXME lto.  Move most of this into a new gimple_asm_set_string().  */
 157         gasm *asm_stmt = as_a <gasm *> (stmt);
 158         tree str;
 159         asm_stmt->ni = streamer_read_uhwi (ib);
 160         asm_stmt->no = streamer_read_uhwi (ib);
 161         asm_stmt->nc = streamer_read_uhwi (ib);
 162         asm_stmt->nl = streamer_read_uhwi (ib);
 163         str = streamer_read_string_cst (data_in, ib);
 164         asm_stmt->string = TREE_STRING_POINTER (str);
 165       }
 166       /* Fallthru  */
 167
 168     case GIMPLE_ASSIGN:
 169     case GIMPLE_CALL:
 170     case GIMPLE_RETURN:
 171     case GIMPLE_SWITCH:
 172     case GIMPLE_LABEL:
 173     case GIMPLE_COND:
 174     case GIMPLE_GOTO:
 175     case GIMPLE_DEBUG:
 176       for (i = 0; i < num_ops; i++)
 177         {
 178           tree *opp, op = stream_read_tree (ib, data_in);
 179           gimple_set_op (stmt, i, op);
 180           if (!op)
 181             continue;
 182
 183           opp = gimple_op_ptr (stmt, i);
 184           if (TREE_CODE (*opp) == ADDR_EXPR)
 185             opp = &TREE_OPERAND (*opp, 0);
 186           while (handled_component_p (*opp))
 187             opp = &TREE_OPERAND (*opp, 0);
 188           /* At LTO output time we wrap all global decls in MEM_REFs to
 189              allow seamless replacement with prevailing decls.  Undo this
 190              here if the prevailing decl allows for this.
 191              ???  Maybe we should simply fold all stmts.  */
 192           if (TREE_CODE (*opp) == MEM_REF
 193               && TREE_CODE (TREE_OPERAND (*opp, 0)) == ADDR_EXPR
 194               && integer_zerop (TREE_OPERAND (*opp, 1))
 195               && (TREE_THIS_VOLATILE (*opp)
 196                   == TREE_THIS_VOLATILE
 197                        (TREE_OPERAND (TREE_OPERAND (*opp, 0), 0)))
 198               && !TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (TREE_OPERAND (*opp, 1)))
 199               && (TREE_TYPE (*opp)
 200                   == TREE_TYPE (TREE_TYPE (TREE_OPERAND (*opp, 1))))
 201               && (TREE_TYPE (*opp)
 202                   == TREE_TYPE (TREE_OPERAND (TREE_OPERAND (*opp, 0), 0))))
 203             *opp = TREE_OPERAND (TREE_OPERAND (*opp, 0), 0);
 204         }
 205       if (gcall *call_stmt = dyn_cast <gcall *> (stmt))
 206         {
 207           if (gimple_call_internal_p (call_stmt))
 208             gimple_call_set_internal_fn
 209               (call_stmt, streamer_read_enum (ib, internal_fn, IFN_LAST));
 210           else
 211             gimple_call_set_fntype (call_stmt, stream_read_tree (ib, data_in));
 212         }
 213       break;
 214
 215     case GIMPLE_NOP:
 216     case GIMPLE_PREDICT:
 217       break;
 218
 219     case GIMPLE_TRANSACTION:
 220       gimple_transaction_set_label (as_a <gtransaction *> (stmt),
 221                                     stream_read_tree (ib, data_in));
 222       break;
 223
 224     default:
 225       internal_error ("bytecode stream: unknown GIMPLE statement tag %s",
 226                       lto_tag_name (tag));
 227     }
 228
 229   /* Update the properties of symbols, SSA names and labels associated
 230      with STMT.  */
 231   if (code == GIMPLE_ASSIGN || code == GIMPLE_CALL)
 232     {
 233       tree lhs = gimple_get_lhs (stmt);
 234       if (lhs && TREE_CODE (lhs) == SSA_NAME)
 235         SSA_NAME_DEF_STMT (lhs) = stmt;
 236     }
 237   else if (code == GIMPLE_ASM)
 238     {
 239       gasm *asm_stmt = as_a <gasm *> (stmt);
 240       unsigned i;
 241
 242       for (i = 0; i < gimple_asm_noutputs (asm_stmt); i++)
 243         {
 244           tree op = TREE_VALUE (gimple_asm_output_op (asm_stmt, i));
 245           if (TREE_CODE (op) == SSA_NAME)
 246             SSA_NAME_DEF_STMT (op) = stmt;
 247         }
 248     }
 249
 250   /* Reset alias information.  */
 251   if (code == GIMPLE_CALL)
 252     gimple_call_reset_alias_info (as_a <gcall *> (stmt));
 253
 254   /* Mark the statement modified so its operand vectors can be filled in.  */
 255   gimple_set_modified (stmt, true);
 256   if (has_hist)
 257     stream_in_histogram_value (ib, stmt);
 258
 259   return stmt;
 260 }
 261
 262
 263 /* Read a basic block with tag TAG from DATA_IN using input block IB.
 264    FN is the function being processed.  */
 265
 266 void
 267 input_bb (struct lto_input_block *ib, enum LTO_tags tag,
 268           struct data_in *data_in, struct function *fn,
 269           int count_materialization_scale)
 270 {
 271   unsigned int index;
 272   basic_block bb;
 273   gimple_stmt_iterator bsi;
 274
 275   /* This routine assumes that CFUN is set to FN, as it needs to call
 276      basic GIMPLE routines that use CFUN.  */
 277   gcc_assert (cfun == fn);
 278
 279   index = streamer_read_uhwi (ib);
 280   bb = BASIC_BLOCK_FOR_FN (fn, index);
 281
 282   bb->count = apply_scale (streamer_read_gcov_count (ib),
 283                            count_materialization_scale);
 284   bb->frequency = streamer_read_hwi (ib);
 285   bb->flags = streamer_read_hwi (ib);
 286
 287   /* LTO_bb1 has statements.  LTO_bb0 does not.  */
 288   if (tag == LTO_bb0)
 289     return;
 290
 291   bsi = gsi_start_bb (bb);
 292   tag = streamer_read_record_start (ib);
 293   while (tag)
 294     {
 295       gimple stmt = input_gimple_stmt (ib, data_in, tag);
 296       gsi_insert_after (&bsi, stmt, GSI_NEW_STMT);
 297
 298       /* After the statement, expect a 0 delimiter or the EH region
 299          that the previous statement belongs to.  */
 300       tag = streamer_read_record_start (ib);
 301       lto_tag_check_set (tag, 2, LTO_eh_region, LTO_null);
 302
 303       if (tag == LTO_eh_region)
 304         {
 305           HOST_WIDE_INT region = streamer_read_hwi (ib);
 306           gcc_assert (region == (int) region);
 307           add_stmt_to_eh_lp (stmt, region);
 308         }
 309
 310       tag = streamer_read_record_start (ib);
 311     }
 312
 313   tag = streamer_read_record_start (ib);
 314   while (tag)
 315     {
 316       input_phi (ib, bb, data_in, fn);
 317       tag = streamer_read_record_start (ib);
 318     }
 319 }