1 /* Read the GIMPLE representation from a file stream.
2 
3    Copyright 2009, 2010 Free Software Foundation, Inc.
4    Contributed by Kenneth Zadeck <zadeck@naturalbridge.com>
5    Re-implemented by Diego Novillo <dnovillo@google.com>
6 
7 This file is part of GCC.
8 
9 GCC is free software; you can redistribute it and/or modify it under
10 the terms of the GNU General Public License as published by the Free
11 Software Foundation; either version 3, or (at your option) any later
12 version.
13 
14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
17 for more details.
18 
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING3.  If not see
21 <http://www.gnu.org/licenses/>.  */
22 
23 #include "config.h"
24 #include "system.h"
25 #include "coretypes.h"
26 #include "tm.h"
27 #include "toplev.h"
28 #include "tree.h"
29 #include "expr.h"
30 #include "flags.h"
31 #include "params.h"
32 #include "input.h"
33 #include "hashtab.h"
34 #include "basic-block.h"
35 #include "tree-flow.h"
36 #include "tree-pass.h"
37 #include "cgraph.h"
38 #include "function.h"
39 #include "ggc.h"
40 #include "diagnostic.h"
41 #include "libfuncs.h"
42 #include "except.h"
43 #include "debug.h"
44 #include "vec.h"
45 #include "timevar.h"
46 #include "output.h"
47 #include "ipa-utils.h"
48 #include "data-streamer.h"
49 #include "gimple-streamer.h"
50 #include "lto-streamer.h"
51 #include "tree-streamer.h"
52 #include "tree-pass.h"
53 #include "streamer-hooks.h"
54 
55 /* The table to hold the file names.  */
56 static htab_t file_name_hash_table;
57 
58 
59 /* Check that tag ACTUAL has one of the given values.  NUM_TAGS is the
60    number of valid tag values to check.  */
61 
62 void
63 lto_tag_check_set (enum LTO_tags actual, int ntags, ...)
64 {
65   va_list ap;
66   int i;
67 
68   va_start (ap, ntags);
69   for (i = 0; i < ntags; i++)
70     if ((unsigned) actual == va_arg (ap, unsigned))
71       {
72 	va_end (ap);
73 	return;
74       }
75 
76   va_end (ap);
77   internal_error ("bytecode stream: unexpected tag %s", lto_tag_name (actual));
78 }
79 
80 
81 /* Read LENGTH bytes from STREAM to ADDR.  */
82 
83 void
84 lto_input_data_block (struct lto_input_block *ib, void *addr, size_t length)
85 {
86   size_t i;
87   unsigned char *const buffer = (unsigned char *const) addr;
88 
89   for (i = 0; i < length; i++)
90     buffer[i] = streamer_read_uchar (ib);
91 }
92 
93 
94 /* Lookup STRING in file_name_hash_table.  If found, return the existing
95    string, otherwise insert STRING as the canonical version.  */
96 
97 static const char *
98 canon_file_name (const char *string)
99 {
100   void **slot;
101   struct string_slot s_slot;
102   size_t len = strlen (string);
103 
104   s_slot.s = string;
105   s_slot.len = len;
106 
107   slot = htab_find_slot (file_name_hash_table, &s_slot, INSERT);
108   if (*slot == NULL)
109     {
110       char *saved_string;
111       struct string_slot *new_slot;
112 
113       saved_string = (char *) xmalloc (len + 1);
114       new_slot = XCNEW (struct string_slot);
115       memcpy (saved_string, string, len + 1);
116       new_slot->s = saved_string;
117       new_slot->len = len;
118       *slot = new_slot;
119       return saved_string;
120     }
121   else
122     {
123       struct string_slot *old_slot = (struct string_slot *) *slot;
124       return old_slot->s;
125     }
126 }
127 
128 
129 /* Clear the line info stored in DATA_IN.  */
130 
131 static void
132 clear_line_info (struct data_in *data_in)
133 {
134   if (data_in->current_file)
135     linemap_add (line_table, LC_LEAVE, false, NULL, 0);
136   data_in->current_file = NULL;
137   data_in->current_line = 0;
138   data_in->current_col = 0;
139 }
140 
141 
142 /* Read a location bitpack from input block IB.  */
143 
144 static location_t
145 lto_input_location_bitpack (struct data_in *data_in, struct bitpack_d *bp)
146 {
147   bool file_change, line_change, column_change;
148   unsigned len;
149   bool prev_file = data_in->current_file != NULL;
150 
151   if (bp_unpack_value (bp, 1))
152     return UNKNOWN_LOCATION;
153 
154   file_change = bp_unpack_value (bp, 1);
155   if (file_change)
156     data_in->current_file = canon_file_name
157 			      (string_for_index (data_in,
158 						 bp_unpack_var_len_unsigned (bp),
159 					         &len));
160 
161   line_change = bp_unpack_value (bp, 1);
162   if (line_change)
163     data_in->current_line = bp_unpack_var_len_unsigned (bp);
164 
165   column_change = bp_unpack_value (bp, 1);
166   if (column_change)
167     data_in->current_col = bp_unpack_var_len_unsigned (bp);
168 
169   if (file_change)
170     {
171       if (prev_file)
172 	linemap_add (line_table, LC_LEAVE, false, NULL, 0);
173 
174       linemap_add (line_table, LC_ENTER, false, data_in->current_file,
175 		   data_in->current_line);
176     }
177   else if (line_change)
178     linemap_line_start (line_table, data_in->current_line, data_in->current_col);
179 
180   return linemap_position_for_column (line_table, data_in->current_col);
181 }
182 
183 
184 /* Read a location from input block IB.
185    If the input_location streamer hook exists, call it.
186    Otherwise, proceed with reading the location from the
187    expanded location bitpack.  */
188 
189 location_t
190 lto_input_location (struct lto_input_block *ib, struct data_in *data_in)
191 {
192   if (streamer_hooks.input_location)
193     return streamer_hooks.input_location (ib, data_in);
194   else
195     {
196       struct bitpack_d bp;
197 
198       bp = streamer_read_bitpack (ib);
199       return lto_input_location_bitpack (data_in, &bp);
200     }
201 }
202 
203 
204 /* Read a reference to a tree node from DATA_IN using input block IB.
205    TAG is the expected node that should be found in IB, if TAG belongs
206    to one of the indexable trees, expect to read a reference index to
207    be looked up in one of the symbol tables, otherwise read the pysical
208    representation of the tree using stream_read_tree.  FN is the
209    function scope for the read tree.  */
210 
211 tree
212 lto_input_tree_ref (struct lto_input_block *ib, struct data_in *data_in,
213 		    struct function *fn, enum LTO_tags tag)
214 {
215   unsigned HOST_WIDE_INT ix_u;
216   tree result = NULL_TREE;
217 
218   lto_tag_check_range (tag, LTO_field_decl_ref, LTO_global_decl_ref);
219 
220   switch (tag)
221     {
222     case LTO_type_ref:
223       ix_u = streamer_read_uhwi (ib);
224       result = lto_file_decl_data_get_type (data_in->file_data, ix_u);
225       break;
226 
227     case LTO_ssa_name_ref:
228       ix_u = streamer_read_uhwi (ib);
229       result = VEC_index (tree, SSANAMES (fn), ix_u);
230       break;
231 
232     case LTO_field_decl_ref:
233       ix_u = streamer_read_uhwi (ib);
234       result = lto_file_decl_data_get_field_decl (data_in->file_data, ix_u);
235       break;
236 
237     case LTO_function_decl_ref:
238       ix_u = streamer_read_uhwi (ib);
239       result = lto_file_decl_data_get_fn_decl (data_in->file_data, ix_u);
240       break;
241 
242     case LTO_type_decl_ref:
243       ix_u = streamer_read_uhwi (ib);
244       result = lto_file_decl_data_get_type_decl (data_in->file_data, ix_u);
245       break;
246 
247     case LTO_namespace_decl_ref:
248       ix_u = streamer_read_uhwi (ib);
249       result = lto_file_decl_data_get_namespace_decl (data_in->file_data, ix_u);
250       break;
251 
252     case LTO_global_decl_ref:
253     case LTO_result_decl_ref:
254     case LTO_const_decl_ref:
255     case LTO_imported_decl_ref:
256     case LTO_label_decl_ref:
257     case LTO_translation_unit_decl_ref:
258       ix_u = streamer_read_uhwi (ib);
259       result = lto_file_decl_data_get_var_decl (data_in->file_data, ix_u);
260       break;
261 
262     default:
263       gcc_unreachable ();
264     }
265 
266   gcc_assert (result);
267 
268   return result;
269 }
270 
271 
272 /* Read and return a double-linked list of catch handlers from input
273    block IB, using descriptors in DATA_IN.  */
274 
275 static struct eh_catch_d *
276 lto_input_eh_catch_list (struct lto_input_block *ib, struct data_in *data_in,
277 			 eh_catch *last_p)
278 {
279   eh_catch first;
280   enum LTO_tags tag;
281 
282   *last_p = first = NULL;
283   tag = streamer_read_record_start (ib);
284   while (tag)
285     {
286       tree list;
287       eh_catch n;
288 
289       lto_tag_check_range (tag, LTO_eh_catch, LTO_eh_catch);
290 
291       /* Read the catch node.  */
292       n = ggc_alloc_cleared_eh_catch_d ();
293       n->type_list = stream_read_tree (ib, data_in);
294       n->filter_list = stream_read_tree (ib, data_in);
295       n->label = stream_read_tree (ib, data_in);
296 
297       /* Register all the types in N->FILTER_LIST.  */
298       for (list = n->filter_list; list; list = TREE_CHAIN (list))
299 	add_type_for_runtime (TREE_VALUE (list));
300 
301       /* Chain N to the end of the list.  */
302       if (*last_p)
303 	(*last_p)->next_catch = n;
304       n->prev_catch = *last_p;
305       *last_p = n;
306 
307       /* Set the head of the list the first time through the loop.  */
308       if (first == NULL)
309 	first = n;
310 
311       tag = streamer_read_record_start (ib);
312     }
313 
314   return first;
315 }
316 
317 
318 /* Read and return EH region IX from input block IB, using descriptors
319    in DATA_IN.  */
320 
321 static eh_region
322 input_eh_region (struct lto_input_block *ib, struct data_in *data_in, int ix)
323 {
324   enum LTO_tags tag;
325   eh_region r;
326 
327   /* Read the region header.  */
328   tag = streamer_read_record_start (ib);
329   if (tag == LTO_null)
330     return NULL;
331 
332   r = ggc_alloc_cleared_eh_region_d ();
333   r->index = streamer_read_hwi (ib);
334 
335   gcc_assert (r->index == ix);
336 
337   /* Read all the region pointers as region numbers.  We'll fix up
338      the pointers once the whole array has been read.  */
339   r->outer = (eh_region) (intptr_t) streamer_read_hwi (ib);
340   r->inner = (eh_region) (intptr_t) streamer_read_hwi (ib);
341   r->next_peer = (eh_region) (intptr_t) streamer_read_hwi (ib);
342 
343   switch (tag)
344     {
345       case LTO_ert_cleanup:
346 	r->type = ERT_CLEANUP;
347 	break;
348 
349       case LTO_ert_try:
350 	{
351 	  struct eh_catch_d *last_catch;
352 	  r->type = ERT_TRY;
353 	  r->u.eh_try.first_catch = lto_input_eh_catch_list (ib, data_in,
354 							     &last_catch);
355 	  r->u.eh_try.last_catch = last_catch;
356 	  break;
357 	}
358 
359       case LTO_ert_allowed_exceptions:
360 	{
361 	  tree l;
362 
363 	  r->type = ERT_ALLOWED_EXCEPTIONS;
364 	  r->u.allowed.type_list = stream_read_tree (ib, data_in);
365 	  r->u.allowed.label = stream_read_tree (ib, data_in);
366 	  r->u.allowed.filter = streamer_read_uhwi (ib);
367 
368 	  for (l = r->u.allowed.type_list; l ; l = TREE_CHAIN (l))
369 	    add_type_for_runtime (TREE_VALUE (l));
370 	}
371 	break;
372 
373       case LTO_ert_must_not_throw:
374 	r->type = ERT_MUST_NOT_THROW;
375 	r->u.must_not_throw.failure_decl = stream_read_tree (ib, data_in);
376 	r->u.must_not_throw.failure_loc = lto_input_location (ib, data_in);
377 	break;
378 
379       default:
380 	gcc_unreachable ();
381     }
382 
383   r->landing_pads = (eh_landing_pad) (intptr_t) streamer_read_hwi (ib);
384 
385   return r;
386 }
387 
388 
389 /* Read and return EH landing pad IX from input block IB, using descriptors
390    in DATA_IN.  */
391 
392 static eh_landing_pad
393 input_eh_lp (struct lto_input_block *ib, struct data_in *data_in, int ix)
394 {
395   enum LTO_tags tag;
396   eh_landing_pad lp;
397 
398   /* Read the landing pad header.  */
399   tag = streamer_read_record_start (ib);
400   if (tag == LTO_null)
401     return NULL;
402 
403   lto_tag_check_range (tag, LTO_eh_landing_pad, LTO_eh_landing_pad);
404 
405   lp = ggc_alloc_cleared_eh_landing_pad_d ();
406   lp->index = streamer_read_hwi (ib);
407   gcc_assert (lp->index == ix);
408   lp->next_lp = (eh_landing_pad) (intptr_t) streamer_read_hwi (ib);
409   lp->region = (eh_region) (intptr_t) streamer_read_hwi (ib);
410   lp->post_landing_pad = stream_read_tree (ib, data_in);
411 
412   return lp;
413 }
414 
415 
416 /* After reading the EH regions, pointers to peer and children regions
417    are region numbers.  This converts all these region numbers into
418    real pointers into the rematerialized regions for FN.  ROOT_REGION
419    is the region number for the root EH region in FN.  */
420 
421 static void
422 fixup_eh_region_pointers (struct function *fn, HOST_WIDE_INT root_region)
423 {
424   unsigned i;
425   VEC(eh_region,gc) *eh_array = fn->eh->region_array;
426   VEC(eh_landing_pad,gc) *lp_array = fn->eh->lp_array;
427   eh_region r;
428   eh_landing_pad lp;
429 
430   gcc_assert (eh_array && lp_array);
431 
432   gcc_assert (root_region >= 0);
433   fn->eh->region_tree = VEC_index (eh_region, eh_array, root_region);
434 
435 #define FIXUP_EH_REGION(r) (r) = VEC_index (eh_region, eh_array, \
436 					    (HOST_WIDE_INT) (intptr_t) (r))
437 #define FIXUP_EH_LP(p) (p) = VEC_index (eh_landing_pad, lp_array, \
438 					(HOST_WIDE_INT) (intptr_t) (p))
439 
440   /* Convert all the index numbers stored in pointer fields into
441      pointers to the corresponding slots in the EH region array.  */
442   FOR_EACH_VEC_ELT (eh_region, eh_array, i, r)
443     {
444       /* The array may contain NULL regions.  */
445       if (r == NULL)
446 	continue;
447 
448       gcc_assert (i == (unsigned) r->index);
449       FIXUP_EH_REGION (r->outer);
450       FIXUP_EH_REGION (r->inner);
451       FIXUP_EH_REGION (r->next_peer);
452       FIXUP_EH_LP (r->landing_pads);
453     }
454 
455   /* Convert all the index numbers stored in pointer fields into
456      pointers to the corresponding slots in the EH landing pad array.  */
457   FOR_EACH_VEC_ELT (eh_landing_pad, lp_array, i, lp)
458     {
459       /* The array may contain NULL landing pads.  */
460       if (lp == NULL)
461 	continue;
462 
463       gcc_assert (i == (unsigned) lp->index);
464       FIXUP_EH_LP (lp->next_lp);
465       FIXUP_EH_REGION (lp->region);
466     }
467 
468 #undef FIXUP_EH_REGION
469 #undef FIXUP_EH_LP
470 }
471 
472 
473 /* Initialize EH support.  */
474 
475 void
476 lto_init_eh (void)
477 {
478   static bool eh_initialized_p = false;
479 
480   if (eh_initialized_p)
481     return;
482 
483   /* Contrary to most other FEs, we only initialize EH support when at
484      least one of the files in the set contains exception regions in
485      it.  Since this happens much later than the call to init_eh in
486      lang_dependent_init, we have to set flag_exceptions and call
487      init_eh again to initialize the EH tables.  */
488   flag_exceptions = 1;
489   init_eh ();
490 
491   eh_initialized_p = true;
492 }
493 
494 
495 /* Read the exception table for FN from IB using the data descriptors
496    in DATA_IN.  */
497 
498 static void
499 input_eh_regions (struct lto_input_block *ib, struct data_in *data_in,
500 		  struct function *fn)
501 {
502   HOST_WIDE_INT i, root_region, len;
503   enum LTO_tags tag;
504 
505   tag = streamer_read_record_start (ib);
506   if (tag == LTO_null)
507     return;
508 
509   lto_tag_check_range (tag, LTO_eh_table, LTO_eh_table);
510 
511   /* If the file contains EH regions, then it was compiled with
512      -fexceptions.  In that case, initialize the backend EH
513      machinery.  */
514   lto_init_eh ();
515 
516   gcc_assert (fn->eh);
517 
518   root_region = streamer_read_hwi (ib);
519   gcc_assert (root_region == (int) root_region);
520 
521   /* Read the EH region array.  */
522   len = streamer_read_hwi (ib);
523   gcc_assert (len == (int) len);
524   if (len > 0)
525     {
526       VEC_safe_grow (eh_region, gc, fn->eh->region_array, len);
527       for (i = 0; i < len; i++)
528 	{
529 	  eh_region r = input_eh_region (ib, data_in, i);
530 	  VEC_replace (eh_region, fn->eh->region_array, i, r);
531 	}
532     }
533 
534   /* Read the landing pads.  */
535   len = streamer_read_hwi (ib);
536   gcc_assert (len == (int) len);
537   if (len > 0)
538     {
539       VEC_safe_grow (eh_landing_pad, gc, fn->eh->lp_array, len);
540       for (i = 0; i < len; i++)
541 	{
542 	  eh_landing_pad lp = input_eh_lp (ib, data_in, i);
543 	  VEC_replace (eh_landing_pad, fn->eh->lp_array, i, lp);
544 	}
545     }
546 
547   /* Read the runtime type data.  */
548   len = streamer_read_hwi (ib);
549   gcc_assert (len == (int) len);
550   if (len > 0)
551     {
552       VEC_safe_grow (tree, gc, fn->eh->ttype_data, len);
553       for (i = 0; i < len; i++)
554 	{
555 	  tree ttype = stream_read_tree (ib, data_in);
556 	  VEC_replace (tree, fn->eh->ttype_data, i, ttype);
557 	}
558     }
559 
560   /* Read the table of action chains.  */
561   len = streamer_read_hwi (ib);
562   gcc_assert (len == (int) len);
563   if (len > 0)
564     {
565       if (targetm.arm_eabi_unwinder)
566 	{
567 	  VEC_safe_grow (tree, gc, fn->eh->ehspec_data.arm_eabi, len);
568 	  for (i = 0; i < len; i++)
569 	    {
570 	      tree t = stream_read_tree (ib, data_in);
571 	      VEC_replace (tree, fn->eh->ehspec_data.arm_eabi, i, t);
572 	    }
573 	}
574       else
575 	{
576 	  VEC_safe_grow (uchar, gc, fn->eh->ehspec_data.other, len);
577 	  for (i = 0; i < len; i++)
578 	    {
579 	      uchar c = streamer_read_uchar (ib);
580 	      VEC_replace (uchar, fn->eh->ehspec_data.other, i, c);
581 	    }
582 	}
583     }
584 
585   /* Reconstruct the EH region tree by fixing up the peer/children
586      pointers.  */
587   fixup_eh_region_pointers (fn, root_region);
588 
589   tag = streamer_read_record_start (ib);
590   lto_tag_check_range (tag, LTO_null, LTO_null);
591 }
592 
593 
594 /* Make a new basic block with index INDEX in function FN.  */
595 
596 static basic_block
597 make_new_block (struct function *fn, unsigned int index)
598 {
599   basic_block bb = alloc_block ();
600   bb->index = index;
601   SET_BASIC_BLOCK_FOR_FUNCTION (fn, index, bb);
602   bb->il.gimple = ggc_alloc_cleared_gimple_bb_info ();
603   n_basic_blocks_for_function (fn)++;
604   bb->flags = 0;
605   set_bb_seq (bb, gimple_seq_alloc ());
606   return bb;
607 }
608 
609 
610 /* Read the CFG for function FN from input block IB.  */
611 
612 static void
613 input_cfg (struct lto_input_block *ib, struct function *fn,
614 	   int count_materialization_scale)
615 {
616   unsigned int bb_count;
617   basic_block p_bb;
618   unsigned int i;
619   int index;
620 
621   init_empty_tree_cfg_for_function (fn);
622   init_ssa_operands ();
623 
624   profile_status_for_function (fn) = streamer_read_enum (ib, profile_status_d,
625 							 PROFILE_LAST);
626 
627   bb_count = streamer_read_uhwi (ib);
628 
629   last_basic_block_for_function (fn) = bb_count;
630   if (bb_count > VEC_length (basic_block, basic_block_info_for_function (fn)))
631     VEC_safe_grow_cleared (basic_block, gc,
632 			   basic_block_info_for_function (fn), bb_count);
633 
634   if (bb_count > VEC_length (basic_block, label_to_block_map_for_function (fn)))
635     VEC_safe_grow_cleared (basic_block, gc,
636 			   label_to_block_map_for_function (fn), bb_count);
637 
638   index = streamer_read_hwi (ib);
639   while (index != -1)
640     {
641       basic_block bb = BASIC_BLOCK_FOR_FUNCTION (fn, index);
642       unsigned int edge_count;
643 
644       if (bb == NULL)
645 	bb = make_new_block (fn, index);
646 
647       edge_count = streamer_read_uhwi (ib);
648 
649       /* Connect up the CFG.  */
650       for (i = 0; i < edge_count; i++)
651 	{
652 	  unsigned int dest_index;
653 	  unsigned int edge_flags;
654 	  basic_block dest;
655 	  int probability;
656 	  gcov_type count;
657 	  edge e;
658 
659 	  dest_index = streamer_read_uhwi (ib);
660 	  probability = (int) streamer_read_hwi (ib);
661 	  count = ((gcov_type) streamer_read_hwi (ib) * count_materialization_scale
662 		   + REG_BR_PROB_BASE / 2) / REG_BR_PROB_BASE;
663 	  edge_flags = streamer_read_uhwi (ib);
664 
665 	  dest = BASIC_BLOCK_FOR_FUNCTION (fn, dest_index);
666 
667 	  if (dest == NULL)
668 	    dest = make_new_block (fn, dest_index);
669 
670 	  e = make_edge (bb, dest, edge_flags);
671 	  e->probability = probability;
672 	  e->count = count;
673 	}
674 
675       index = streamer_read_hwi (ib);
676     }
677 
678   p_bb = ENTRY_BLOCK_PTR_FOR_FUNCTION(fn);
679   index = streamer_read_hwi (ib);
680   while (index != -1)
681     {
682       basic_block bb = BASIC_BLOCK_FOR_FUNCTION (fn, index);
683       bb->prev_bb = p_bb;
684       p_bb->next_bb = bb;
685       p_bb = bb;
686       index = streamer_read_hwi (ib);
687     }
688 }
689 
690 
691 /* Read the SSA names array for function FN from DATA_IN using input
692    block IB.  */
693 
694 static void
695 input_ssa_names (struct lto_input_block *ib, struct data_in *data_in,
696 		 struct function *fn)
697 {
698   unsigned int i, size;
699 
700   size = streamer_read_uhwi (ib);
701   init_ssanames (fn, size);
702 
703   i = streamer_read_uhwi (ib);
704   while (i)
705     {
706       tree ssa_name, name;
707       bool is_default_def;
708 
709       /* Skip over the elements that had been freed.  */
710       while (VEC_length (tree, SSANAMES (fn)) < i)
711 	VEC_quick_push (tree, SSANAMES (fn), NULL_TREE);
712 
713       is_default_def = (streamer_read_uchar (ib) != 0);
714       name = stream_read_tree (ib, data_in);
715       ssa_name = make_ssa_name_fn (fn, name, gimple_build_nop ());
716 
717       if (is_default_def)
718 	set_default_def (SSA_NAME_VAR (ssa_name), ssa_name);
719 
720       i = streamer_read_uhwi (ib);
721     }
722 }
723 
724 
725 /* Go through all NODE edges and fixup call_stmt pointers
726    so they point to STMTS.  */
727 
728 static void
729 fixup_call_stmt_edges_1 (struct cgraph_node *node, gimple *stmts)
730 {
731   struct cgraph_edge *cedge;
732   for (cedge = node->callees; cedge; cedge = cedge->next_callee)
733     cedge->call_stmt = stmts[cedge->lto_stmt_uid];
734   for (cedge = node->indirect_calls; cedge; cedge = cedge->next_callee)
735     cedge->call_stmt = stmts[cedge->lto_stmt_uid];
736 }
737 
738 /* Fixup call_stmt pointers in NODE and all clones.  */
739 
740 static void
741 fixup_call_stmt_edges (struct cgraph_node *orig, gimple *stmts)
742 {
743   struct cgraph_node *node;
744 
745   while (orig->clone_of)
746     orig = orig->clone_of;
747 
748   fixup_call_stmt_edges_1 (orig, stmts);
749   if (orig->clones)
750     for (node = orig->clones; node != orig;)
751       {
752 	fixup_call_stmt_edges_1 (node, stmts);
753 	if (node->clones)
754 	  node = node->clones;
755 	else if (node->next_sibling_clone)
756 	  node = node->next_sibling_clone;
757 	else
758 	  {
759 	    while (node != orig && !node->next_sibling_clone)
760 	      node = node->clone_of;
761 	    if (node != orig)
762 	      node = node->next_sibling_clone;
763 	  }
764       }
765 }
766 
767 
768 /* Input the base body of struct function FN from DATA_IN
769    using input block IB.  */
770 
771 static void
772 input_struct_function_base (struct function *fn, struct data_in *data_in,
773                             struct lto_input_block *ib)
774 {
775   struct bitpack_d bp;
776   int len;
777 
778   /* Read the static chain and non-local goto save area.  */
779   fn->static_chain_decl = stream_read_tree (ib, data_in);
780   fn->nonlocal_goto_save_area = stream_read_tree (ib, data_in);
781 
782   /* Read all the local symbols.  */
783   len = streamer_read_hwi (ib);
784   if (len > 0)
785     {
786       int i;
787       VEC_safe_grow (tree, gc, fn->local_decls, len);
788       for (i = 0; i < len; i++)
789 	{
790 	  tree t = stream_read_tree (ib, data_in);
791 	  VEC_replace (tree, fn->local_decls, i, t);
792 	}
793     }
794 
795   /* Input the function start and end loci.  */
796   fn->function_start_locus = lto_input_location (ib, data_in);
797   fn->function_end_locus = lto_input_location (ib, data_in);
798 
799   /* Input the current IL state of the function.  */
800   fn->curr_properties = streamer_read_uhwi (ib);
801 
802   /* Read all the attributes for FN.  */
803   bp = streamer_read_bitpack (ib);
804   fn->is_thunk = bp_unpack_value (&bp, 1);
805   fn->has_local_explicit_reg_vars = bp_unpack_value (&bp, 1);
806   fn->after_tree_profile = bp_unpack_value (&bp, 1);
807   fn->returns_pcc_struct = bp_unpack_value (&bp, 1);
808   fn->returns_struct = bp_unpack_value (&bp, 1);
809   fn->can_throw_non_call_exceptions = bp_unpack_value (&bp, 1);
810   fn->always_inline_functions_inlined = bp_unpack_value (&bp, 1);
811   fn->after_inlining = bp_unpack_value (&bp, 1);
812   fn->stdarg = bp_unpack_value (&bp, 1);
813   fn->has_nonlocal_label = bp_unpack_value (&bp, 1);
814   fn->calls_alloca = bp_unpack_value (&bp, 1);
815   fn->calls_setjmp = bp_unpack_value (&bp, 1);
816   fn->va_list_fpr_size = bp_unpack_value (&bp, 8);
817   fn->va_list_gpr_size = bp_unpack_value (&bp, 8);
818 }
819 
820 
821 /* Read the body of function FN_DECL from DATA_IN using input block IB.  */
822 
823 static void
824 input_function (tree fn_decl, struct data_in *data_in,
825 		struct lto_input_block *ib)
826 {
827   struct function *fn;
828   enum LTO_tags tag;
829   gimple *stmts;
830   basic_block bb;
831   struct cgraph_node *node;
832   tree args, narg, oarg;
833 
834   fn = DECL_STRUCT_FUNCTION (fn_decl);
835   tag = streamer_read_record_start (ib);
836   clear_line_info (data_in);
837 
838   gimple_register_cfg_hooks ();
839   lto_tag_check (tag, LTO_function);
840 
841   input_struct_function_base (fn, data_in, ib);
842 
843   /* Read all function arguments.  We need to re-map them here to the
844      arguments of the merged function declaration.  */
845   args = stream_read_tree (ib, data_in);
846   for (oarg = args, narg = DECL_ARGUMENTS (fn_decl);
847        oarg && narg;
848        oarg = TREE_CHAIN (oarg), narg = TREE_CHAIN (narg))
849     {
850       unsigned ix;
851       bool res;
852       res = streamer_tree_cache_lookup (data_in->reader_cache, oarg, &ix);
853       gcc_assert (res);
854       /* Replace the argument in the streamer cache.  */
855       streamer_tree_cache_insert_at (data_in->reader_cache, narg, ix);
856     }
857   gcc_assert (!oarg && !narg);
858 
859   /* Read all the SSA names.  */
860   input_ssa_names (ib, data_in, fn);
861 
862   /* Read the exception handling regions in the function.  */
863   input_eh_regions (ib, data_in, fn);
864 
865   /* Read the tree of lexical scopes for the function.  */
866   DECL_INITIAL (fn_decl) = stream_read_tree (ib, data_in);
867   gcc_assert (DECL_INITIAL (fn_decl));
868   DECL_SAVED_TREE (fn_decl) = NULL_TREE;
869   node = cgraph_get_create_node (fn_decl);
870 
871   /* Read all the basic blocks.  */
872   tag = streamer_read_record_start (ib);
873   while (tag)
874     {
875       input_bb (ib, tag, data_in, fn,
876 		node->count_materialization_scale);
877       tag = streamer_read_record_start (ib);
878     }
879 
880   /* Fix up the call statements that are mentioned in the callgraph
881      edges.  */
882   set_gimple_stmt_max_uid (cfun, 0);
883   FOR_ALL_BB (bb)
884     {
885       gimple_stmt_iterator gsi;
886       for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
887 	{
888 	  gimple stmt = gsi_stmt (gsi);
889 	  gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun));
890 	}
891     }
892   stmts = (gimple *) xcalloc (gimple_stmt_max_uid (fn), sizeof (gimple));
893   FOR_ALL_BB (bb)
894     {
895       gimple_stmt_iterator bsi = gsi_start_bb (bb);
896       while (!gsi_end_p (bsi))
897 	{
898 	  gimple stmt = gsi_stmt (bsi);
899 	  /* If we're recompiling LTO objects with debug stmts but
900 	     we're not supposed to have debug stmts, remove them now.
901 	     We can't remove them earlier because this would cause uid
902 	     mismatches in fixups, but we can do it at this point, as
903 	     long as debug stmts don't require fixups.  */
904 	  if (!MAY_HAVE_DEBUG_STMTS && is_gimple_debug (stmt))
905 	    {
906 	      gimple_stmt_iterator gsi = bsi;
907 	      gsi_next (&bsi);
908 	      gsi_remove (&gsi, true);
909 	    }
910 	  else
911 	    {
912 	      gsi_next (&bsi);
913 	      stmts[gimple_uid (stmt)] = stmt;
914 	    }
915 	}
916     }
917 
918   /* Set the gimple body to the statement sequence in the entry
919      basic block.  FIXME lto, this is fairly hacky.  The existence
920      of a gimple body is used by the cgraph routines, but we should
921      really use the presence of the CFG.  */
922   {
923     edge_iterator ei = ei_start (ENTRY_BLOCK_PTR->succs);
924     gimple_set_body (fn_decl, bb_seq (ei_edge (ei)->dest));
925   }
926 
927   fixup_call_stmt_edges (node, stmts);
928   execute_all_ipa_stmt_fixups (node, stmts);
929 
930   update_ssa (TODO_update_ssa_only_virtuals);
931   free_dominance_info (CDI_DOMINATORS);
932   free_dominance_info (CDI_POST_DOMINATORS);
933   free (stmts);
934 }
935 
936 
937 /* Read initializer expressions for public statics.  DATA_IN is the
938    file being read.  IB is the input block used for reading.  */
939 
940 static void
941 input_alias_pairs (struct lto_input_block *ib, struct data_in *data_in)
942 {
943   tree var;
944 
945   clear_line_info (data_in);
946 
947   var = stream_read_tree (ib, data_in);
948   while (var)
949     {
950       const char *orig_name, *new_name;
951       alias_pair *p;
952 
953       p = VEC_safe_push (alias_pair, gc, alias_pairs, NULL);
954       p->decl = var;
955       p->target = stream_read_tree (ib, data_in);
956 
957       /* If the target is a static object, we may have registered a
958 	 new name for it to avoid clashes between statics coming from
959 	 different files.  In that case, use the new name.  */
960       orig_name = IDENTIFIER_POINTER (p->target);
961       new_name = lto_get_decl_name_mapping (data_in->file_data, orig_name);
962       if (strcmp (orig_name, new_name) != 0)
963 	p->target = get_identifier (new_name);
964 
965       var = stream_read_tree (ib, data_in);
966     }
967 }
968 
969 
970 /* Read the body from DATA for function FN_DECL and fill it in.
971    FILE_DATA are the global decls and types.  SECTION_TYPE is either
972    LTO_section_function_body or LTO_section_static_initializer.  If
973    section type is LTO_section_function_body, FN must be the decl for
974    that function.  */
975 
976 static void
977 lto_read_body (struct lto_file_decl_data *file_data, tree fn_decl,
978 	       const char *data, enum lto_section_type section_type)
979 {
980   const struct lto_function_header *header;
981   struct data_in *data_in;
982   int cfg_offset;
983   int main_offset;
984   int string_offset;
985   struct lto_input_block ib_cfg;
986   struct lto_input_block ib_main;
987 
988   header = (const struct lto_function_header *) data;
989   cfg_offset = sizeof (struct lto_function_header);
990   main_offset = cfg_offset + header->cfg_size;
991   string_offset = main_offset + header->main_size;
992 
993   LTO_INIT_INPUT_BLOCK (ib_cfg,
994 		        data + cfg_offset,
995 			0,
996 			header->cfg_size);
997 
998   LTO_INIT_INPUT_BLOCK (ib_main,
999 			data + main_offset,
1000 			0,
1001 			header->main_size);
1002 
1003   data_in = lto_data_in_create (file_data, data + string_offset,
1004 				header->string_size, NULL);
1005 
1006   /* Make sure the file was generated by the exact same compiler.  */
1007   lto_check_version (header->lto_header.major_version,
1008 		     header->lto_header.minor_version);
1009 
1010   if (section_type == LTO_section_function_body)
1011     {
1012       struct function *fn = DECL_STRUCT_FUNCTION (fn_decl);
1013       struct lto_in_decl_state *decl_state;
1014       struct cgraph_node *node = cgraph_get_node (fn_decl);
1015       unsigned from;
1016 
1017       gcc_checking_assert (node);
1018       push_cfun (fn);
1019       init_tree_ssa (fn);
1020 
1021       /* Use the function's decl state. */
1022       decl_state = lto_get_function_in_decl_state (file_data, fn_decl);
1023       gcc_assert (decl_state);
1024       file_data->current_decl_state = decl_state;
1025 
1026       input_cfg (&ib_cfg, fn, node->count_materialization_scale);
1027 
1028       /* Set up the struct function.  */
1029       from = VEC_length (tree, data_in->reader_cache->nodes);
1030       input_function (fn_decl, data_in, &ib_main);
1031       /* And fixup types we streamed locally.  */
1032 	{
1033 	  struct streamer_tree_cache_d *cache = data_in->reader_cache;
1034 	  unsigned len = VEC_length (tree, cache->nodes);
1035 	  unsigned i;
1036 	  for (i = len; i-- > from;)
1037 	    {
1038 	      tree t = VEC_index (tree, cache->nodes, i);
1039 	      if (t == NULL_TREE)
1040 		continue;
1041 
1042 	      if (TYPE_P (t))
1043 		{
1044 		  gcc_assert (TYPE_CANONICAL (t) == NULL_TREE);
1045 		  TYPE_CANONICAL (t) = TYPE_MAIN_VARIANT (t);
1046 		  if (TYPE_MAIN_VARIANT (t) != t)
1047 		    {
1048 		      gcc_assert (TYPE_NEXT_VARIANT (t) == NULL_TREE);
1049 		      TYPE_NEXT_VARIANT (t)
1050 			= TYPE_NEXT_VARIANT (TYPE_MAIN_VARIANT (t));
1051 		      TYPE_NEXT_VARIANT (TYPE_MAIN_VARIANT (t)) = t;
1052 		    }
1053 		}
1054 	    }
1055 	}
1056 
1057       /* We should now be in SSA.  */
1058       cfun->gimple_df->in_ssa_p = true;
1059 
1060       /* Restore decl state */
1061       file_data->current_decl_state = file_data->global_decl_state;
1062 
1063       pop_cfun ();
1064     }
1065   else
1066     {
1067       input_alias_pairs (&ib_main, data_in);
1068     }
1069 
1070   clear_line_info (data_in);
1071   lto_data_in_delete (data_in);
1072 }
1073 
1074 
1075 /* Read the body of FN_DECL using DATA.  FILE_DATA holds the global
1076    decls and types.  */
1077 
1078 void
1079 lto_input_function_body (struct lto_file_decl_data *file_data,
1080 			 tree fn_decl, const char *data)
1081 {
1082   current_function_decl = fn_decl;
1083   lto_read_body (file_data, fn_decl, data, LTO_section_function_body);
1084 }
1085 
1086 
1087 /* Read in VAR_DECL using DATA.  FILE_DATA holds the global decls and
1088    types.  */
1089 
1090 void
1091 lto_input_constructors_and_inits (struct lto_file_decl_data *file_data,
1092 				  const char *data)
1093 {
1094   lto_read_body (file_data, NULL, data, LTO_section_static_initializer);
1095 }
1096 
1097 
1098 /* Read the physical representation of a tree node with tag TAG from
1099    input block IB using the per-file context in DATA_IN.  */
1100 
1101 static tree
1102 lto_read_tree (struct lto_input_block *ib, struct data_in *data_in,
1103 	       enum LTO_tags tag)
1104 {
1105   /* Instantiate a new tree node.  */
1106   tree result = streamer_alloc_tree (ib, data_in, tag);
1107 
1108   /* Enter RESULT in the reader cache.  This will make RESULT
1109      available so that circular references in the rest of the tree
1110      structure can be resolved in subsequent calls to stream_read_tree.  */
1111   streamer_tree_cache_append (data_in->reader_cache, result);
1112 
1113   /* Read all the bitfield values in RESULT.  Note that for LTO, we
1114      only write language-independent bitfields, so no more unpacking is
1115      needed.  */
1116   streamer_read_tree_bitfields (ib, result);
1117 
1118   /* Read all the pointer fields in RESULT.  */
1119   streamer_read_tree_body (ib, data_in, result);
1120 
1121   /* Read any LTO-specific data not read by the tree streamer.  */
1122   if (DECL_P (result)
1123       && TREE_CODE (result) != FUNCTION_DECL
1124       && TREE_CODE (result) != TRANSLATION_UNIT_DECL)
1125     DECL_INITIAL (result) = stream_read_tree (ib, data_in);
1126 
1127   /* We should never try to instantiate an MD or NORMAL builtin here.  */
1128   if (TREE_CODE (result) == FUNCTION_DECL)
1129     gcc_assert (!streamer_handle_as_builtin_p (result));
1130 
1131   /* end_marker = */ streamer_read_uchar (ib);
1132 
1133 #ifdef LTO_STREAMER_DEBUG
1134   /* Remove the mapping to RESULT's original address set by
1135      streamer_alloc_tree.  */
1136   lto_orig_address_remove (result);
1137 #endif
1138 
1139   return result;
1140 }
1141 
1142 
1143 /* Read a tree from input block IB using the per-file context in
1144    DATA_IN.  This context is used, for example, to resolve references
1145    to previously read nodes.  */
1146 
1147 tree
1148 lto_input_tree (struct lto_input_block *ib, struct data_in *data_in)
1149 {
1150   enum LTO_tags tag;
1151   tree result;
1152 
1153   tag = streamer_read_record_start (ib);
1154   gcc_assert ((unsigned) tag < (unsigned) LTO_NUM_TAGS);
1155 
1156   if (tag == LTO_null)
1157     result = NULL_TREE;
1158   else if (tag >= LTO_field_decl_ref && tag <= LTO_global_decl_ref)
1159     {
1160       /* If TAG is a reference to an indexable tree, the next value
1161 	 in IB is the index into the table where we expect to find
1162 	 that tree.  */
1163       result = lto_input_tree_ref (ib, data_in, cfun, tag);
1164     }
1165   else if (tag == LTO_tree_pickle_reference)
1166     {
1167       /* If TAG is a reference to a previously read tree, look it up in
1168 	 the reader cache.  */
1169       result = streamer_get_pickled_tree (ib, data_in);
1170     }
1171   else if (tag == LTO_builtin_decl)
1172     {
1173       /* If we are going to read a built-in function, all we need is
1174 	 the code and class.  */
1175       result = streamer_get_builtin_tree (ib, data_in);
1176     }
1177   else if (tag == lto_tree_code_to_tag (INTEGER_CST))
1178     {
1179       /* For integer constants we only need the type and its hi/low
1180 	 words.  */
1181       result = streamer_read_integer_cst (ib, data_in);
1182     }
1183   else
1184     {
1185       /* Otherwise, materialize a new node from IB.  */
1186       result = lto_read_tree (ib, data_in, tag);
1187     }
1188 
1189   return result;
1190 }
1191 
1192 
1193 /* Input toplevel asms.  */
1194 
1195 void
1196 lto_input_toplevel_asms (struct lto_file_decl_data *file_data, int order_base)
1197 {
1198   size_t len;
1199   const char *data = lto_get_section_data (file_data, LTO_section_asm,
1200 					   NULL, &len);
1201   const struct lto_asm_header *header = (const struct lto_asm_header *) data;
1202   int string_offset;
1203   struct data_in *data_in;
1204   struct lto_input_block ib;
1205   tree str;
1206 
1207   if (! data)
1208     return;
1209 
1210   string_offset = sizeof (*header) + header->main_size;
1211 
1212   LTO_INIT_INPUT_BLOCK (ib,
1213 			data + sizeof (*header),
1214 			0,
1215 			header->main_size);
1216 
1217   data_in = lto_data_in_create (file_data, data + string_offset,
1218 				header->string_size, NULL);
1219 
1220   /* Make sure the file was generated by the exact same compiler.  */
1221   lto_check_version (header->lto_header.major_version,
1222 		     header->lto_header.minor_version);
1223 
1224   while ((str = streamer_read_string_cst (data_in, &ib)))
1225     {
1226       struct cgraph_asm_node *node = cgraph_add_asm_node (str);
1227       node->order = streamer_read_hwi (&ib) + order_base;
1228       if (node->order >= cgraph_order)
1229 	cgraph_order = node->order + 1;
1230     }
1231 
1232   clear_line_info (data_in);
1233   lto_data_in_delete (data_in);
1234 
1235   lto_free_section_data (file_data, LTO_section_asm, NULL, data, len);
1236 }
1237 
1238 
1239 /* Initialization for the LTO reader.  */
1240 
1241 void
1242 lto_reader_init (void)
1243 {
1244   lto_streamer_init ();
1245   file_name_hash_table = htab_create (37, hash_string_slot_node,
1246 				      eq_string_slot_node, free);
1247 }
1248 
1249 
1250 /* Create a new data_in object for FILE_DATA. STRINGS is the string
1251    table to use with LEN strings.  RESOLUTIONS is the vector of linker
1252    resolutions (NULL if not using a linker plugin).  */
1253 
1254 struct data_in *
1255 lto_data_in_create (struct lto_file_decl_data *file_data, const char *strings,
1256 		    unsigned len,
1257 		    VEC(ld_plugin_symbol_resolution_t,heap) *resolutions)
1258 {
1259   struct data_in *data_in = XCNEW (struct data_in);
1260   data_in->file_data = file_data;
1261   data_in->strings = strings;
1262   data_in->strings_len = len;
1263   data_in->globals_resolution = resolutions;
1264   data_in->reader_cache = streamer_tree_cache_create ();
1265 
1266   return data_in;
1267 }
1268 
1269 
1270 /* Remove DATA_IN.  */
1271 
1272 void
1273 lto_data_in_delete (struct data_in *data_in)
1274 {
1275   VEC_free (ld_plugin_symbol_resolution_t, heap, data_in->globals_resolution);
1276   streamer_tree_cache_delete (data_in->reader_cache);
1277   free (data_in->labels);
1278   free (data_in);
1279 }
1280