mono/mini/seq-points.c

   1 /**
   2  * \file
   3  * Sequence Points functions
   4  *
   5  * Authors:
   6  *   Marcos Henrich (marcos.henrich@xamarin.com)
   7  *
   8  * Copyright 2014 Xamarin, Inc (http://www.xamarin.com)
   9  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
  10  */
  11
  12 #include "mini.h"
  13 #include "mini-runtime.h"
  14 #include "seq-points.h"
  15
  16 static void
  17 insert_pred_seq_point (MonoInst *last_seq_ins, MonoInst *ins, GSList **next)
  18 {
  19         GSList *l;
  20         int src_index = last_seq_ins->backend.size;
  21         int dst_index = ins->backend.size;
  22
  23         /* bb->in_bb might contain duplicates */
  24         for (l = next [src_index]; l; l = l->next)
  25                 if (GPOINTER_TO_UINT (l->data) == dst_index)
  26                         break;
  27         if (!l)
  28                 next [src_index] = g_slist_append (next [src_index], GUINT_TO_POINTER (dst_index));
  29 }
  30
  31 static void
  32 recursively_make_pred_seq_points (MonoCompile *cfg, MonoBasicBlock *bb)
  33 {
  34         const gpointer MONO_SEQ_SEEN_LOOP = GINT_TO_POINTER(-1);
  35
  36         GArray *predecessors = g_array_new (FALSE, TRUE, sizeof (gpointer));
  37         GHashTable *seen = g_hash_table_new_full (g_direct_hash, NULL, NULL, NULL);
  38
  39         // Insert/remove sentinel into the memoize table to detect loops containing bb
  40         bb->pred_seq_points = MONO_SEQ_SEEN_LOOP;
  41
  42         for (int i = 0; i < bb->in_count; ++i) {
  43                 MonoBasicBlock *in_bb = bb->in_bb [i];
  44
  45                 // This bb has the last seq point, append it and continue
  46                 if (in_bb->last_seq_point != NULL) {
  47                         predecessors = g_array_append_val (predecessors, in_bb->last_seq_point);
  48                         continue;
  49                 }
  50
  51                 // We've looped or handled this before, exit early.
  52                 // No last sequence points to find.
  53                 if (in_bb->pred_seq_points == MONO_SEQ_SEEN_LOOP)
  54                         continue;
  55
  56                 // Take sequence points from incoming basic blocks
  57
  58                 if (in_bb == cfg->bb_entry)
  59                         continue;
  60
  61                 if (in_bb->pred_seq_points == NULL)
  62                         recursively_make_pred_seq_points (cfg, in_bb);
  63
  64                 // Union sequence points with incoming bb's
  65                 for (int i=0; i < in_bb->num_pred_seq_points; i++) {
  66                         if (!g_hash_table_lookup (seen, in_bb->pred_seq_points [i])) {
  67                                 g_array_append_val (predecessors, in_bb->pred_seq_points [i]);
  68                                 g_hash_table_insert (seen, in_bb->pred_seq_points [i], (gpointer)&MONO_SEQ_SEEN_LOOP);
  69                         }
  70                 }
  71                 // predecessors = g_array_append_vals (predecessors, in_bb->pred_seq_points, in_bb->num_pred_seq_points);
  72         }
  73
  74         g_hash_table_destroy (seen);
  75
  76         if (predecessors->len != 0) {
  77                 bb->pred_seq_points = (MonoInst **)mono_mempool_alloc0 (cfg->mempool, sizeof (MonoInst *) * predecessors->len);
  78                 bb->num_pred_seq_points = predecessors->len;
  79
  80                 for (int newer = 0; newer < bb->num_pred_seq_points; newer++) {
  81                         bb->pred_seq_points [newer] = g_array_index(predecessors, gpointer, newer);
  82                 }
  83         }
  84
  85         g_array_free (predecessors, TRUE);
  86 }
  87
  88 static void
  89 collect_pred_seq_points (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, GSList **next)
  90 {
  91         // Doesn't have a last sequence point, must find from incoming basic blocks
  92         if (bb->pred_seq_points == NULL && bb != cfg->bb_entry)
  93                 recursively_make_pred_seq_points (cfg, bb);
  94
  95         for (int i = 0; i < bb->num_pred_seq_points; i++)
  96                 insert_pred_seq_point (bb->pred_seq_points [i], ins, next);
  97
  98         return;
  99 }
 100
 101 void
 102 mono_save_seq_point_info (MonoCompile *cfg)
 103 {
 104         MonoBasicBlock *bb;
 105         GSList *bb_seq_points, *l;
 106         MonoInst *last;
 107         MonoDomain *domain = cfg->domain;
 108         int i, seq_info_size;
 109         GSList **next = NULL;
 110         SeqPoint* seq_points;
 111         GByteArray* array;
 112         gboolean has_debug_data = cfg->gen_sdb_seq_points;
 113
 114         if (!cfg->seq_points)
 115                 return;
 116
 117         seq_points = g_new0 (SeqPoint, cfg->seq_points->len);
 118
 119         for (i = 0; i < cfg->seq_points->len; ++i) {
 120                 SeqPoint *sp = &seq_points [i];
 121                 MonoInst *ins = (MonoInst *)g_ptr_array_index (cfg->seq_points, i);
 122
 123                 sp->il_offset = ins->inst_imm;
 124                 sp->native_offset = ins->inst_offset;
 125                 if (ins->flags & MONO_INST_NONEMPTY_STACK)
 126                         sp->flags |= MONO_SEQ_POINT_FLAG_NONEMPTY_STACK;
 127
 128                 /* Used below */
 129                 ins->backend.size = i;
 130         }
 131
 132         if (has_debug_data) {
 133                 /*
 134                  * For each sequence point, compute the list of sequence points immediately
 135                  * following it, this is needed to implement 'step over' in the debugger agent.
 136                  */
 137                 next = g_new0 (GSList*, cfg->seq_points->len);
 138                 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
 139                         bb_seq_points = g_slist_reverse (bb->seq_points);
 140                         last = NULL;
 141                         for (l = bb_seq_points; l; l = l->next) {
 142                                 MonoInst *ins = (MonoInst *)l->data;
 143
 144                                 if (ins->inst_imm == METHOD_ENTRY_IL_OFFSET || ins->inst_imm == METHOD_EXIT_IL_OFFSET)
 145                                 /* Used to implement method entry/exit events */
 146                                         continue;
 147                                 if (ins->inst_offset == SEQ_POINT_NATIVE_OFFSET_DEAD_CODE)
 148                                         continue;
 149
 150                                 if (last != NULL) {
 151                                         /* Link with the previous seq point in the same bb */
 152                                         next [last->backend.size] = g_slist_append (next [last->backend.size], GUINT_TO_POINTER (ins->backend.size));
 153                                 } else {
 154                                         /* Link with the last bb in the previous bblocks */
 155                                         collect_pred_seq_points (cfg, bb, ins, next);
 156                                 }
 157
 158                                 last = ins;
 159                         }
 160
 161                         /* The second case handles endfinally opcodes which are in a separate bb by themselves */
 162                         if ((bb->last_ins && bb->last_ins->opcode == OP_ENDFINALLY && bb->seq_points) || (bb->out_count == 1 && bb->out_bb [0]->code && bb->out_bb [0]->code->opcode == OP_ENDFINALLY)) {
 163                                 MonoBasicBlock *bb2;
 164                                 MonoInst *endfinally_seq_point = NULL;
 165
 166                                 /*
 167                                  * The ENDFINALLY branches are not represented in the cfg, so link it with all seq points starting bbs.
 168                                  */
 169                                 l = g_slist_last (bb->seq_points);
 170                                 if (l) {
 171                                         endfinally_seq_point = (MonoInst *)l->data;
 172
 173                                         for (bb2 = bb->next_bb; bb2; bb2 = bb2->next_bb) {
 174                                                 GSList *l = g_slist_last (bb2->seq_points);
 175
 176                                                 if (l) {
 177                                                         MonoInst *ins = (MonoInst *)l->data;
 178
 179                                                         if (!(ins->inst_imm == METHOD_ENTRY_IL_OFFSET || ins->inst_imm == METHOD_EXIT_IL_OFFSET) && ins != endfinally_seq_point)
 180                                                                 next [endfinally_seq_point->backend.size] = g_slist_append (next [endfinally_seq_point->backend.size], GUINT_TO_POINTER (ins->backend.size));
 181                                                 }
 182                                         }
 183                                 }
 184                         }
 185                 }
 186
 187                 if (cfg->verbose_level > 2) {
 188                         printf ("\nSEQ POINT MAP: \n");
 189
 190                         for (i = 0; i < cfg->seq_points->len; ++i) {
 191                                 SeqPoint *sp = &seq_points [i];
 192                                 GSList *l;
 193
 194                                 if (!next [i])
 195                                         continue;
 196
 197                                 printf ("\tIL0x%x[0x%0x] ->", sp->il_offset, sp->native_offset);
 198                                 for (l = next [i]; l; l = l->next) {
 199                                         int next_index = GPOINTER_TO_UINT (l->data);
 200                                         printf (" IL0x%x", seq_points [next_index].il_offset);
 201                                 }
 202                                 printf ("\n");
 203                         }
 204                 }
 205         }
 206
 207         array = g_byte_array_new ();
 208
 209         { /* Add sequence points to seq_point_info */
 210                 SeqPoint zero_seq_point = {0};
 211                 SeqPoint* last_seq_point = &zero_seq_point;
 212
 213                 for (i = 0; i < cfg->seq_points->len; ++i) {
 214                         SeqPoint *sp = &seq_points [i];
 215                         GSList* next_list = NULL;
 216
 217                         if (has_debug_data)
 218                                 next_list = next[i];
 219
 220                         if (mono_seq_point_info_add_seq_point (array, sp, last_seq_point, next_list, has_debug_data))
 221                                 last_seq_point = sp;
 222
 223                         if (has_debug_data)
 224                                 g_slist_free (next [i]);
 225                 }
 226         }
 227
 228         g_free (seq_points);
 229
 230         if (has_debug_data)
 231                 g_free (next);
 232
 233         cfg->seq_point_info = mono_seq_point_info_new (array->len, TRUE, array->data, has_debug_data, &seq_info_size);
 234         mono_atomic_fetch_add_i32 (&mono_jit_stats.allocated_seq_points_size, seq_info_size);
 235
 236         g_byte_array_free (array, TRUE);
 237
 238         // FIXME: dynamic methods
 239         if (!cfg->compile_aot) {
 240                 mono_domain_lock (domain);
 241                 // FIXME: The lookup can fail if the method is JITted recursively though a type cctor
 242                 if (!g_hash_table_lookup (domain_jit_info (domain)->seq_points, cfg->method_to_register))
 243                         g_hash_table_insert (domain_jit_info (domain)->seq_points, cfg->method_to_register, cfg->seq_point_info);
 244                 else
 245                         mono_seq_point_info_free (cfg->seq_point_info);
 246                 mono_domain_unlock (domain);
 247         }
 248
 249         g_ptr_array_free (cfg->seq_points, TRUE);
 250         cfg->seq_points = NULL;
 251 }
 252
 253 MonoSeqPointInfo*
 254 mono_get_seq_points (MonoDomain *domain, MonoMethod *method)
 255 {
 256         ERROR_DECL (error);
 257         MonoSeqPointInfo *seq_points;
 258         MonoMethod *declaring_generic_method = NULL, *shared_method = NULL;
 259
 260         if (method->is_inflated) {
 261                 declaring_generic_method = mono_method_get_declaring_generic_method (method);
 262                 shared_method = mini_get_shared_method_full (method, SHARE_MODE_NONE, error);
 263                 mono_error_assert_ok (error);
 264         }
 265
 266         mono_loader_lock ();
 267         seq_points = (MonoSeqPointInfo *)g_hash_table_lookup (domain_jit_info (domain)->seq_points, method);
 268         if (!seq_points && method->is_inflated) {
 269                 /* generic sharing + aot */
 270                 seq_points = (MonoSeqPointInfo *)g_hash_table_lookup (domain_jit_info (domain)->seq_points, declaring_generic_method);
 271                 if (!seq_points)
 272                         seq_points = (MonoSeqPointInfo *)g_hash_table_lookup (domain_jit_info (domain)->seq_points, shared_method);
 273         }
 274         mono_loader_unlock ();
 275
 276         return seq_points;
 277 }
 278
 279 /*
 280  * mono_find_next_seq_point_for_native_offset:
 281  *
 282  *   Find the first sequence point after NATIVE_OFFSET.
 283  */
 284 gboolean
 285 mono_find_next_seq_point_for_native_offset (MonoDomain *domain, MonoMethod *method, gint32 native_offset, MonoSeqPointInfo **info, SeqPoint* seq_point)
 286 {
 287         MonoSeqPointInfo *seq_points;
 288
 289         seq_points = mono_get_seq_points (domain, method);
 290         if (!seq_points) {
 291                 if (info)
 292                         *info = NULL;
 293                 return FALSE;
 294         }
 295         if (info)
 296                 *info = seq_points;
 297
 298         return mono_seq_point_find_next_by_native_offset (seq_points, native_offset, seq_point);
 299 }
 300
 301 /*
 302  * mono_find_prev_seq_point_for_native_offset:
 303  *
 304  *   Find the first sequence point before NATIVE_OFFSET.
 305  */
 306 gboolean
 307 mono_find_prev_seq_point_for_native_offset (MonoDomain *domain, MonoMethod *method, gint32 native_offset, MonoSeqPointInfo **info, SeqPoint* seq_point)
 308 {
 309         MonoSeqPointInfo *seq_points;
 310
 311         seq_points = mono_get_seq_points (domain, method);
 312         if (!seq_points) {
 313                 if (info)
 314                         *info = NULL;
 315                 return FALSE;
 316         }
 317         if (info)
 318                 *info = seq_points;
 319
 320         return mono_seq_point_find_prev_by_native_offset (seq_points, native_offset, seq_point);
 321 }
 322
 323 /*
 324  * mono_find_seq_point:
 325  *
 326  *   Find the sequence point corresponding to the IL offset IL_OFFSET, which
 327  * should be the location of a sequence point.
 328  */
 329 gboolean
 330 mono_find_seq_point (MonoDomain *domain, MonoMethod *method, gint32 il_offset, MonoSeqPointInfo **info, SeqPoint *seq_point)
 331 {
 332         MonoSeqPointInfo *seq_points;
 333
 334         seq_points = mono_get_seq_points (domain, method);
 335         if (!seq_points) {
 336                 if (info)
 337                         *info = NULL;
 338                 return FALSE;
 339         }
 340         if (info)
 341                 *info = seq_points;
 342
 343         return mono_seq_point_find_by_il_offset (seq_points, il_offset, seq_point);
 344 }
 345
 346 void
 347 mono_bb_deduplicate_op_il_seq_points (MonoCompile *cfg, MonoBasicBlock *bb)
 348 {
 349         MonoInst *ins, *n, *prev;
 350
 351         MONO_BB_FOR_EACH_INS_SAFE (bb, n, ins) {
 352                 if (ins->opcode != OP_IL_SEQ_POINT)
 353                         continue;
 354
 355                 prev = mono_inst_prev (ins, FILTER_NOP);
 356
 357                 if (!prev || ins == prev || prev->opcode != OP_IL_SEQ_POINT)
 358                         continue;
 359
 360                 MONO_REMOVE_INS (bb, prev);
 361         };
 362 }