aboutsummaryrefslogtreecommitdiff
path: root/gdb/amd64-windows-tdep.c
blob: 4e750a10bffa1e0484fc0c085f59872c1292f093 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
/* Copyright (C) 2009-2013 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "osabi.h"
#include "amd64-tdep.h"
#include "solib.h"
#include "solib-target.h"
#include "gdbtypes.h"
#include "gdbcore.h"
#include "regcache.h"
#include "windows-tdep.h"
#include "frame.h"
#include "objfiles.h"
#include "frame-unwind.h"
#include "coff/internal.h"
#include "coff/i386.h"
#include "coff/pe.h"
#include "libcoff.h"

/* The registers used to pass integer arguments during a function call.  */
static int amd64_windows_dummy_call_integer_regs[] =
{
  AMD64_RCX_REGNUM,          /* %rcx */
  AMD64_RDX_REGNUM,          /* %rdx */
  8,                         /* %r8 */
  9                          /* %r9 */
};

/* Implement the "classify" method in the gdbarch_tdep structure
   for amd64-windows.  */

static void
amd64_windows_classify (struct type *type, enum amd64_reg_class class[2])
{
  switch (TYPE_CODE (type))
    {
      case TYPE_CODE_ARRAY:
	/* Arrays are always passed by memory.	*/
	class[0] = class[1] = AMD64_MEMORY;
	break;

      case TYPE_CODE_STRUCT:
      case TYPE_CODE_UNION:
        /* Struct/Union types whose size is 1, 2, 4, or 8 bytes
	   are passed as if they were integers of the same size.
	   Types of different sizes are passed by memory.  */
	if (TYPE_LENGTH (type) == 1
	    || TYPE_LENGTH (type) == 2
	    || TYPE_LENGTH (type) == 4
	    || TYPE_LENGTH (type) == 8)
	  {
	    class[0] = AMD64_INTEGER;
	    class[1] = AMD64_NO_CLASS;
	  }
	else
	  class[0] = class[1] = AMD64_MEMORY;
	break;

      default:
	/* For all the other types, the conventions are the same as
	   with the System V ABI.  */
	amd64_classify (type, class);
    }
}

/* Implement the "return_value" gdbarch method for amd64-windows.  */

static enum return_value_convention
amd64_windows_return_value (struct gdbarch *gdbarch, struct value *function,
			    struct type *type, struct regcache *regcache,
			    gdb_byte *readbuf, const gdb_byte *writebuf)
{
  int len = TYPE_LENGTH (type);
  int regnum = -1;

  /* See if our value is returned through a register.  If it is, then
     store the associated register number in REGNUM.  */
  switch (TYPE_CODE (type))
    {
      case TYPE_CODE_FLT:
      case TYPE_CODE_DECFLOAT:
        /* __m128, __m128i, __m128d, floats, and doubles are returned
           via XMM0.  */
        if (len == 4 || len == 8 || len == 16)
          regnum = AMD64_XMM0_REGNUM;
        break;
      default:
        /* All other values that are 1, 2, 4 or 8 bytes long are returned
           via RAX.  */
        if (len == 1 || len == 2 || len == 4 || len == 8)
          regnum = AMD64_RAX_REGNUM;
        break;
    }

  if (regnum < 0)
    {
      /* RAX contains the address where the return value has been stored.  */
      if (readbuf)
        {
	  ULONGEST addr;

	  regcache_raw_read_unsigned (regcache, AMD64_RAX_REGNUM, &addr);
	  read_memory (addr, readbuf, TYPE_LENGTH (type));
	}
      return RETURN_VALUE_ABI_RETURNS_ADDRESS;
    }
  else
    {
      /* Extract the return value from the register where it was stored.  */
      if (readbuf)
	regcache_raw_read_part (regcache, regnum, 0, len, readbuf);
      if (writebuf)
	regcache_raw_write_part (regcache, regnum, 0, len, writebuf);
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
}

/* Check that the code pointed to by PC corresponds to a call to
   __main, skip it if so.  Return PC otherwise.  */

static CORE_ADDR
amd64_skip_main_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
{
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  gdb_byte op;

  target_read_memory (pc, &op, 1);
  if (op == 0xe8)
    {
      gdb_byte buf[4];

      if (target_read_memory (pc + 1, buf, sizeof buf) == 0)
 	{
 	  struct bound_minimal_symbol s;
 	  CORE_ADDR call_dest;

	  call_dest = pc + 5 + extract_signed_integer (buf, 4, byte_order);
 	  s = lookup_minimal_symbol_by_pc (call_dest);
 	  if (s.minsym != NULL
 	      && SYMBOL_LINKAGE_NAME (s.minsym) != NULL
 	      && strcmp (SYMBOL_LINKAGE_NAME (s.minsym), "__main") == 0)
 	    pc += 5;
 	}
    }

  return pc;
}

struct amd64_windows_frame_cache
{
  /* ImageBase for the module.  */
  CORE_ADDR image_base;

  /* Function start and end rva.  */
  CORE_ADDR start_rva;
  CORE_ADDR end_rva;

  /* Next instruction to be executed.  */
  CORE_ADDR pc;

  /* Current sp.  */
  CORE_ADDR sp;

  /* Address of saved integer and xmm registers.  */
  CORE_ADDR prev_reg_addr[16];
  CORE_ADDR prev_xmm_addr[16];

  /* These two next fields are set only for machine info frames.  */

  /* Likewise for RIP.  */
  CORE_ADDR prev_rip_addr;

  /* Likewise for RSP.  */
  CORE_ADDR prev_rsp_addr;

  /* Address of the previous frame.  */
  CORE_ADDR prev_sp;
};

/* Convert a Windows register number to gdb.  */
static const enum amd64_regnum amd64_windows_w2gdb_regnum[] =
{
  AMD64_RAX_REGNUM,
  AMD64_RCX_REGNUM,
  AMD64_RDX_REGNUM,
  AMD64_RBX_REGNUM,
  AMD64_RSP_REGNUM,
  AMD64_RBP_REGNUM,
  AMD64_RSI_REGNUM,
  AMD64_RDI_REGNUM,
  AMD64_R8_REGNUM,
  AMD64_R9_REGNUM,
  AMD64_R10_REGNUM,
  AMD64_R11_REGNUM,
  AMD64_R12_REGNUM,
  AMD64_R13_REGNUM,
  AMD64_R14_REGNUM,
  AMD64_R15_REGNUM
};

/* Return TRUE iff PC is the the range of the function corresponding to
   CACHE.  */

static int
pc_in_range (CORE_ADDR pc, const struct amd64_windows_frame_cache *cache)
{
  return (pc >= cache->image_base + cache->start_rva
	  && pc < cache->image_base + cache->end_rva);
}

/* Try to recognize and decode an epilogue sequence.

   Return -1 if we fail to read the instructions for any reason.
   Return 1 if an epilogue sequence was recognized, 0 otherwise.  */

static int
amd64_windows_frame_decode_epilogue (struct frame_info *this_frame,
				     struct amd64_windows_frame_cache *cache)
{
  /* According to MSDN an epilogue "must consist of either an add RSP,constant
     or lea RSP,constant[FPReg], followed by a series of zero or more 8-byte
     register pops and a return or a jmp".

     Furthermore, according to RtlVirtualUnwind, the complete list of
     epilog marker is:
     - ret                      [c3]
     - ret n                    [c2 imm16]
     - rep ret                  [f3 c3]
     - jmp imm8 | imm32         [eb rel8] or [e9 rel32]
     - jmp qword ptr imm32                 - not handled
     - rex.w jmp reg            [4X ff eY]
  */

  CORE_ADDR pc = cache->pc;
  CORE_ADDR cur_sp = cache->sp;
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  gdb_byte op;
  gdb_byte rex;

  /* We don't care about the instruction deallocating the frame:
     if it hasn't been executed, the pc is still in the body,
     if it has been executed, the following epilog decoding will work.  */

  /* First decode:
     -  pop reg                 [41 58-5f] or [58-5f].  */

  while (1)
    {
      /* Read opcode. */
      if (target_read_memory (pc, &op, 1) != 0)
	return -1;

      if (op >= 0x40 && op <= 0x4f)
	{
	  /* REX prefix.  */
	  rex = op;

	  /* Read opcode. */
	  if (target_read_memory (pc + 1, &op, 1) != 0)
	    return -1;
	}
      else
	rex = 0;

      if (op >= 0x58 && op <= 0x5f)
	{
	  /* pop reg  */
	  gdb_byte reg = (op & 0x0f) | ((rex & 1) << 3);

	  cache->prev_reg_addr[amd64_windows_w2gdb_regnum[reg]] = cur_sp;
	  cur_sp += 8;
	}
      else
	break;

      /* Allow the user to break this loop.  This shouldn't happen as the
	 number of consecutive pop should be small.  */
      QUIT;
    }

  /* Then decode the marker.  */

  /* Read opcode.  */
  if (target_read_memory (pc, &op, 1) != 0)
    return -1;

  switch (op)
    {
    case 0xc3:
      /* Ret.  */
      cache->prev_rip_addr = cur_sp;
      cache->prev_sp = cur_sp + 8;
      return 1;

    case 0xeb:
      {
	/* jmp rel8  */
	gdb_byte rel8;
	CORE_ADDR npc;

	if (target_read_memory (pc + 1, &rel8, 1) != 0)
	  return -1;
	npc = pc + 2 + (signed char) rel8;

	/* If the jump is within the function, then this is not a marker,
	   otherwise this is a tail-call.  */
	return !pc_in_range (npc, cache);
      }

    case 0xec:
      {
	/* jmp rel32  */
	gdb_byte rel32[4];
	CORE_ADDR npc;

	if (target_read_memory (pc + 1, rel32, 4) != 0)
	  return -1;
	npc = pc + 5 + extract_signed_integer (rel32, 4, byte_order);

	/* If the jump is within the function, then this is not a marker,
	   otherwise this is a tail-call.  */
	return !pc_in_range (npc, cache);
      }

    case 0xc2:
      {
	/* ret n  */
	gdb_byte imm16[2];

	if (target_read_memory (pc + 1, imm16, 2) != 0)
	  return -1;
	cache->prev_rip_addr = cur_sp;
	cache->prev_sp = cur_sp
	  + extract_unsigned_integer (imm16, 4, byte_order);
	return 1;
      }

    case 0xf3:
      {
	/* rep; ret  */
	gdb_byte op1;

	if (target_read_memory (pc + 2, &op1, 1) != 0)
	  return -1;
	if (op1 != 0xc3)
	  return 0;

	cache->prev_rip_addr = cur_sp;
	cache->prev_sp = cur_sp + 8;
	return 1;
      }

    case 0x40:
    case 0x41:
    case 0x42:
    case 0x43:
    case 0x44:
    case 0x45:
    case 0x46:
    case 0x47:
    case 0x48:
    case 0x49:
    case 0x4a:
    case 0x4b:
    case 0x4c:
    case 0x4d:
    case 0x4e:
    case 0x4f:
      /* Got a REX prefix, read next byte.  */
      rex = op;
      if (target_read_memory (pc + 1, &op, 1) != 0)
	return -1;

      if (op == 0xff)
	{
	  /* rex jmp reg  */
	  gdb_byte op1;
	  unsigned int reg;
	  gdb_byte buf[8];

	  if (target_read_memory (pc + 2, &op1, 1) != 0)
	    return -1;
	  return (op1 & 0xf8) == 0xe0;
	}
      else
	return 0;

    default:
      /* Not REX, so unknown.  */
      return 0;
    }
}

/* Decode and execute unwind insns at UNWIND_INFO.  */

static void
amd64_windows_frame_decode_insns (struct frame_info *this_frame,
				  struct amd64_windows_frame_cache *cache,
				  CORE_ADDR unwind_info)
{
  CORE_ADDR save_addr = 0;
  CORE_ADDR cur_sp = cache->sp;
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  int j;

  for (j = 0; ; j++)
    {
      struct external_pex64_unwind_info ex_ui;
      /* There are at most 256 16-bit unwind insns.  */
      gdb_byte insns[2 * 256];
      gdb_byte *p;
      gdb_byte *end_insns;
      unsigned char codes_count;
      unsigned char frame_reg;
      unsigned char frame_off;

      /* Read and decode header.  */
      if (target_read_memory (cache->image_base + unwind_info,
			      (gdb_byte *) &ex_ui, sizeof (ex_ui)) != 0)
	return;

      if (frame_debug)
	fprintf_unfiltered
	  (gdb_stdlog,
	   "amd64_windows_frame_decodes_insn: "
	   "%s: ver: %02x, plgsz: %02x, cnt: %02x, frame: %02x\n",
	   paddress (gdbarch, unwind_info),
	   ex_ui.Version_Flags, ex_ui.SizeOfPrologue,
	   ex_ui.CountOfCodes, ex_ui.FrameRegisterOffset);

      /* Check version.  */
      if (PEX64_UWI_VERSION (ex_ui.Version_Flags) != 1)
	return;

      if (j == 0
	  && (cache->pc >=
	      cache->image_base + cache->start_rva + ex_ui.SizeOfPrologue))
	{
	  /* Not in the prologue.  We want to detect if the PC points to an
	     epilogue. If so, the epilogue detection+decoding function is
	     sufficient.  Otherwise, the unwinder will consider that the PC
	     is in the body of the function and will need to decode unwind
	     info.  */
	  if (amd64_windows_frame_decode_epilogue (this_frame, cache) == 1)
	    return;

	  /* Not in an epilog.  Clear possible side effects.  */
	  memset (cache->prev_reg_addr, 0, sizeof (cache->prev_reg_addr));
	}

      codes_count = ex_ui.CountOfCodes;
      frame_reg = PEX64_UWI_FRAMEREG (ex_ui.FrameRegisterOffset);

      if (frame_reg != 0)
	{
	  /* According to msdn:
	     If an FP reg is used, then any unwind code taking an offset must
	     only be used after the FP reg is established in the prolog.  */
	  gdb_byte buf[8];
	  int frreg = amd64_windows_w2gdb_regnum[frame_reg];

	  get_frame_register (this_frame, frreg, buf);
	  save_addr = extract_unsigned_integer (buf, 8, byte_order);

	  if (frame_debug)
	    fprintf_unfiltered (gdb_stdlog, "   frame_reg=%s, val=%s\n",
				gdbarch_register_name (gdbarch, frreg),
				paddress (gdbarch, save_addr));
	}

      /* Read opcodes.  */
      if (codes_count != 0
	  && target_read_memory (cache->image_base + unwind_info
				 + sizeof (ex_ui),
				 insns, codes_count * 2) != 0)
	return;

      end_insns = &insns[codes_count * 2];
      for (p = insns; p < end_insns; p += 2)
	{
	  int reg;

	  if (frame_debug)
	    fprintf_unfiltered
	      (gdb_stdlog, "   op #%u: off=0x%02x, insn=0x%02x\n",
	       (unsigned) (p - insns), p[0], p[1]);

	  /* Virtually execute the operation.  */
	  if (cache->pc >= cache->image_base + cache->start_rva + p[0])
	    {
	      /* If there is no frame registers defined, the current value of
		 rsp is used instead.  */
	      if (frame_reg == 0)
		save_addr = cur_sp;

	      switch (PEX64_UNWCODE_CODE (p[1]))
		{
		case UWOP_PUSH_NONVOL:
		  /* Push pre-decrements RSP.  */
		  reg = amd64_windows_w2gdb_regnum[PEX64_UNWCODE_INFO (p[1])];
		  cache->prev_reg_addr[reg] = cur_sp;
		  cur_sp += 8;
		  break;
		case UWOP_ALLOC_LARGE:
		  if (PEX64_UNWCODE_INFO (p[1]) == 0)
		    cur_sp +=
		      8 * extract_unsigned_integer (p + 2, 2, byte_order);
		  else if (PEX64_UNWCODE_INFO (p[1]) == 1)
		    cur_sp += extract_unsigned_integer (p + 2, 4, byte_order);
		  else
		    return;
		  break;
		case UWOP_ALLOC_SMALL:
		  cur_sp += 8 + 8 * PEX64_UNWCODE_INFO (p[1]);
		  break;
		case UWOP_SET_FPREG:
		  cur_sp = save_addr
		    - PEX64_UWI_FRAMEOFF (ex_ui.FrameRegisterOffset) * 16;
		  break;
		case UWOP_SAVE_NONVOL:
		  reg = amd64_windows_w2gdb_regnum[PEX64_UNWCODE_INFO (p[1])];
		  cache->prev_reg_addr[reg] = save_addr
		    - 8 * extract_unsigned_integer (p + 2, 2, byte_order);
		  break;
		case UWOP_SAVE_NONVOL_FAR:
		  reg = amd64_windows_w2gdb_regnum[PEX64_UNWCODE_INFO (p[1])];
		  cache->prev_reg_addr[reg] = save_addr
		    - 8 * extract_unsigned_integer (p + 2, 4, byte_order);
		  break;
		case UWOP_SAVE_XMM128:
		  cache->prev_xmm_addr[PEX64_UNWCODE_INFO (p[1])] =
		    save_addr
		    - 16 * extract_unsigned_integer (p + 2, 2, byte_order);
		  break;
		case UWOP_SAVE_XMM128_FAR:
		  cache->prev_xmm_addr[PEX64_UNWCODE_INFO (p[1])] =
		    save_addr
		    - 16 * extract_unsigned_integer (p + 2, 4, byte_order);
		  break;
		case UWOP_PUSH_MACHFRAME:
		  if (PEX64_UNWCODE_INFO (p[1]) == 0)
		    {
		      cache->prev_rip_addr = cur_sp + 0;
		      cache->prev_rsp_addr = cur_sp + 24;
		      cur_sp += 40;
		    }
		  else if (PEX64_UNWCODE_INFO (p[1]) == 1)
		    {
		      cache->prev_rip_addr = cur_sp + 8;
		      cache->prev_rsp_addr = cur_sp + 32;
		      cur_sp += 48;
		    }
		  else
		    return;
		  break;
		default:
		  return;
		}
	    }

	  /* Adjust with the length of the opcode.  */
	  switch (PEX64_UNWCODE_CODE (p[1]))
	    {
	    case UWOP_PUSH_NONVOL:
	    case UWOP_ALLOC_SMALL:
	    case UWOP_SET_FPREG:
	    case UWOP_PUSH_MACHFRAME:
	      break;
	    case UWOP_ALLOC_LARGE:
	      if (PEX64_UNWCODE_INFO (p[1]) == 0)
		p += 2;
	      else if (PEX64_UNWCODE_INFO (p[1]) == 1)
		p += 4;
	      else
		return;
	      break;
	    case UWOP_SAVE_NONVOL:
	    case UWOP_SAVE_XMM128:
	      p += 2;
	      break;
	    case UWOP_SAVE_NONVOL_FAR:
	    case UWOP_SAVE_XMM128_FAR:
	      p += 4;
	      break;
	    default:
	      return;
	    }
	}
      if (PEX64_UWI_FLAGS (ex_ui.Version_Flags) != UNW_FLAG_CHAININFO)
	break;
      else
	{
	  /* Read the chained unwind info.  */
	  struct external_pex64_runtime_function d;
	  CORE_ADDR chain_vma;

	  chain_vma = cache->image_base + unwind_info
	    + sizeof (ex_ui) + ((codes_count + 1) & ~1) * 2 + 8;

	  if (target_read_memory (chain_vma, (gdb_byte *) &d, sizeof (d)) != 0)
	    return;

	  cache->start_rva =
	    extract_unsigned_integer (d.rva_BeginAddress, 4, byte_order);
	  cache->end_rva =
	    extract_unsigned_integer (d.rva_EndAddress, 4, byte_order);
	  unwind_info =
	    extract_unsigned_integer (d.rva_UnwindData, 4, byte_order);
	}

      /* Allow the user to break this loop.  */
      QUIT;
    }
  /* PC is saved by the call.  */
  if (cache->prev_rip_addr == 0)
    cache->prev_rip_addr = cur_sp;
  cache->prev_sp = cur_sp + 8;

  if (frame_debug)
    fprintf_unfiltered (gdb_stdlog, "   prev_sp: %s, prev_pc @%s\n",
			paddress (gdbarch, cache->prev_sp),
			paddress (gdbarch, cache->prev_rip_addr));
}

/* Find SEH unwind info for PC, returning 0 on success.

   UNWIND_INFO is set to the rva of unwind info address, IMAGE_BASE
   to the base address of the corresponding image, and START_RVA
   to the rva of the function containing PC.  */

static int
amd64_windows_find_unwind_info (struct gdbarch *gdbarch, CORE_ADDR pc,
				CORE_ADDR *unwind_info,
				CORE_ADDR *image_base,
				CORE_ADDR *start_rva,
				CORE_ADDR *end_rva)
{
  struct obj_section *sec;
  pe_data_type *pe;
  IMAGE_DATA_DIRECTORY *dir;
  struct objfile *objfile;
  unsigned long lo, hi;
  CORE_ADDR base;
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  /* Get the corresponding exception directory.  */
  sec = find_pc_section (pc);
  if (sec == NULL)
    return -1;
  objfile = sec->objfile;
  pe = pe_data (sec->objfile->obfd);
  dir = &pe->pe_opthdr.DataDirectory[PE_EXCEPTION_TABLE];

  base = pe->pe_opthdr.ImageBase
    + ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
  *image_base = base;

  /* Find the entry.

     Note: This does not handle dynamically added entries (for JIT
     engines).  For this, we would need to ask the kernel directly,
     which means getting some info from the native layer.  For the
     rest of the code, however, it's probably faster to search
     the entry ourselves.  */
  lo = 0;
  hi = dir->Size / sizeof (struct external_pex64_runtime_function);
  *unwind_info = 0;
  while (lo <= hi)
    {
      unsigned long mid = lo + (hi - lo) / 2;
      struct external_pex64_runtime_function d;
      CORE_ADDR sa, ea;

      if (target_read_memory (base + dir->VirtualAddress + mid * sizeof (d),
			      (gdb_byte *) &d, sizeof (d)) != 0)
	return -1;

      sa = extract_unsigned_integer (d.rva_BeginAddress, 4, byte_order);
      ea = extract_unsigned_integer (d.rva_EndAddress, 4, byte_order);
      if (pc < base + sa)
	hi = mid - 1;
      else if (pc >= base + ea)
	lo = mid + 1;
      else if (pc >= base + sa && pc < base + ea)
	{
	  /* Got it.  */
	  *start_rva = sa;
	  *end_rva = ea;
	  *unwind_info =
	    extract_unsigned_integer (d.rva_UnwindData, 4, byte_order);
	  break;
	}
      else
	break;
    }

  if (frame_debug)
    fprintf_unfiltered
      (gdb_stdlog,
       "amd64_windows_find_unwind_data:  image_base=%s, unwind_data=%s\n",
       paddress (gdbarch, base), paddress (gdbarch, *unwind_info));

  if (*unwind_info & 1)
    {
      /* Unofficially documented unwind info redirection, when UNWIND_INFO
	 address is odd (http://www.codemachine.com/article_x64deepdive.html).
      */
      struct external_pex64_runtime_function d;
      CORE_ADDR sa, ea;

      if (target_read_memory (base + (*unwind_info & ~1),
			      (gdb_byte *) &d, sizeof (d)) != 0)
	return -1;

      *start_rva =
	extract_unsigned_integer (d.rva_BeginAddress, 4, byte_order);
      *end_rva = extract_unsigned_integer (d.rva_EndAddress, 4, byte_order);
      *unwind_info =
	extract_unsigned_integer (d.rva_UnwindData, 4, byte_order);

    }
  return 0;
}

/* Fill THIS_CACHE using the native amd64-windows unwinding data
   for THIS_FRAME.  */

static struct amd64_windows_frame_cache *
amd64_windows_frame_cache (struct frame_info *this_frame, void **this_cache)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  struct amd64_windows_frame_cache *cache;
  gdb_byte buf[8];
  struct obj_section *sec;
  pe_data_type *pe;
  IMAGE_DATA_DIRECTORY *dir;
  CORE_ADDR image_base;
  CORE_ADDR pc;
  struct objfile *objfile;
  unsigned long lo, hi;
  CORE_ADDR unwind_info = 0;

  if (*this_cache)
    return *this_cache;

  cache = FRAME_OBSTACK_ZALLOC (struct amd64_windows_frame_cache);
  *this_cache = cache;

  /* Get current PC and SP.  */
  pc = get_frame_pc (this_frame);
  get_frame_register (this_frame, AMD64_RSP_REGNUM, buf);
  cache->sp = extract_unsigned_integer (buf, 8, byte_order);
  cache->pc = pc;

  if (amd64_windows_find_unwind_info (gdbarch, pc, &unwind_info,
				      &cache->image_base,
				      &cache->start_rva,
				      &cache->end_rva))
    return cache;

  if (unwind_info == 0)
    {
      /* Assume a leaf function.  */
      cache->prev_sp = cache->sp + 8;
      cache->prev_rip_addr = cache->sp;
    }
  else
    {
      /* Decode unwind insns to compute saved addresses.  */
      amd64_windows_frame_decode_insns (this_frame, cache, unwind_info);
    }
  return cache;
}

/* Implement the "prev_register" method of struct frame_unwind
   using the standard Windows x64 SEH info.  */

static struct value *
amd64_windows_frame_prev_register (struct frame_info *this_frame,
				   void **this_cache, int regnum)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  struct amd64_windows_frame_cache *cache =
    amd64_windows_frame_cache (this_frame, this_cache);
  struct value *val;
  CORE_ADDR prev;

  if (frame_debug)
    fprintf_unfiltered (gdb_stdlog,
			"amd64_windows_frame_prev_register %s for sp=%s\n",
			gdbarch_register_name (gdbarch, regnum),
			paddress (gdbarch, cache->prev_sp));

  if (regnum >= AMD64_XMM0_REGNUM && regnum <= AMD64_XMM0_REGNUM + 15)
      prev = cache->prev_xmm_addr[regnum - AMD64_XMM0_REGNUM];
  else if (regnum == AMD64_RSP_REGNUM)
    {
      prev = cache->prev_rsp_addr;
      if (prev == 0)
	return frame_unwind_got_constant (this_frame, regnum, cache->prev_sp);
    }
  else if (regnum >= AMD64_RAX_REGNUM && regnum <= AMD64_R15_REGNUM)
    prev = cache->prev_reg_addr[regnum - AMD64_RAX_REGNUM];
  else if (regnum == AMD64_RIP_REGNUM)
    prev = cache->prev_rip_addr;
  else
    prev = 0;

  if (prev && frame_debug)
    fprintf_unfiltered (gdb_stdlog, "  -> at %s\n", paddress (gdbarch, prev));

  if (prev)
    {
      /* Register was saved.  */
      return frame_unwind_got_memory (this_frame, regnum, prev);
    }
  else
    {
      /* Register is either volatile or not modified.  */
      return frame_unwind_got_register (this_frame, regnum, regnum);
    }
}

/* Implement the "this_id" method of struct frame_unwind using
   the standard Windows x64 SEH info.  */

static void
amd64_windows_frame_this_id (struct frame_info *this_frame, void **this_cache,
		   struct frame_id *this_id)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  struct amd64_windows_frame_cache *cache =
    amd64_windows_frame_cache (this_frame, this_cache);

  *this_id = frame_id_build (cache->prev_sp,
			     cache->image_base + cache->start_rva);
}

/* Windows x64 SEH unwinder.  */

static const struct frame_unwind amd64_windows_frame_unwind =
{
  NORMAL_FRAME,
  default_frame_unwind_stop_reason,
  &amd64_windows_frame_this_id,
  &amd64_windows_frame_prev_register,
  NULL,
  default_frame_sniffer
};

/* Implement the "skip_prologue" gdbarch method.  */

static CORE_ADDR
amd64_windows_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
{
  CORE_ADDR func_addr;
  CORE_ADDR unwind_info = 0;
  CORE_ADDR image_base, start_rva, end_rva;
  struct external_pex64_unwind_info ex_ui;

  /* Use prologue size from unwind info.  */
  if (amd64_windows_find_unwind_info (gdbarch, pc, &unwind_info,
				      &image_base, &start_rva, &end_rva) == 0)
    {
      if (unwind_info == 0)
	{
	  /* Leaf function.  */
	  return pc;
	}
      else if (target_read_memory (image_base + unwind_info,
				   (gdb_byte *) &ex_ui, sizeof (ex_ui)) == 0
	       && PEX64_UWI_VERSION (ex_ui.Version_Flags) == 1)
	return max (pc, image_base + start_rva + ex_ui.SizeOfPrologue);
    }

  /* See if we can determine the end of the prologue via the symbol
     table.  If so, then return either the PC, or the PC after
     the prologue, whichever is greater.  */
  if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
    {
      CORE_ADDR post_prologue_pc
	= skip_prologue_using_sal (gdbarch, func_addr);

      if (post_prologue_pc != 0)
	return max (pc, post_prologue_pc);
    }

  return pc;
}

/* Check Win64 DLL jmp trampolines and find jump destination.  */

static CORE_ADDR
amd64_windows_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
{
  CORE_ADDR destination = 0;
  struct gdbarch *gdbarch = get_frame_arch (frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);

  /* Check for jmp *<offset>(%rip) (jump near, absolute indirect (/4)).  */
  if (pc && read_memory_unsigned_integer (pc, 2, byte_order) == 0x25ff)
    {
      /* Get opcode offset and see if we can find a reference in our data.  */
      ULONGEST offset
	= read_memory_unsigned_integer (pc + 2, 4, byte_order);

      /* Get address of function pointer at end of pc.  */
      CORE_ADDR indirect_addr = pc + offset + 6;

      struct minimal_symbol *indsym
	= (indirect_addr
	   ? lookup_minimal_symbol_by_pc (indirect_addr).minsym
	   : NULL);
      const char *symname = indsym ? SYMBOL_LINKAGE_NAME (indsym) : NULL;

      if (symname)
	{
	  if (strncmp (symname, "__imp_", 6) == 0
	      || strncmp (symname, "_imp_", 5) == 0)
	    destination
	      = read_memory_unsigned_integer (indirect_addr, 8, byte_order);
	}
    }

  return destination;
}

/* Implement the "auto_wide_charset" gdbarch method.  */

static const char *
amd64_windows_auto_wide_charset (void)
{
  return "UTF-16";
}

static void
amd64_windows_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  /* The dwarf2 unwinder (appended very early by i386_gdbarch_init) is
     preferred over the SEH one.  The reasons are:
     - binaries without SEH but with dwarf2 debug info are correcly handled
       (although they aren't ABI compliant, gcc before 4.7 didn't emit SEH
       info).
     - dwarf3 DW_OP_call_frame_cfa is correctly handled (it can only be
       handled if the dwarf2 unwinder is used).

    The call to amd64_init_abi appends default unwinders, that aren't
    compatible with the SEH one.
  */
  frame_unwind_append_unwinder (gdbarch, &amd64_windows_frame_unwind);

  amd64_init_abi (info, gdbarch);

  /* On Windows, "long"s are only 32bit.  */
  set_gdbarch_long_bit (gdbarch, 32);

  /* Function calls.  */
  tdep->call_dummy_num_integer_regs =
    ARRAY_SIZE (amd64_windows_dummy_call_integer_regs);
  tdep->call_dummy_integer_regs = amd64_windows_dummy_call_integer_regs;
  tdep->classify = amd64_windows_classify;
  tdep->memory_args_by_pointer = 1;
  tdep->integer_param_regs_saved_in_caller_frame = 1;
  set_gdbarch_return_value (gdbarch, amd64_windows_return_value);
  set_gdbarch_skip_main_prologue (gdbarch, amd64_skip_main_prologue);
  set_gdbarch_skip_trampoline_code (gdbarch,
				    amd64_windows_skip_trampoline_code);

  set_gdbarch_iterate_over_objfiles_in_search_order
    (gdbarch, windows_iterate_over_objfiles_in_search_order);

  set_gdbarch_skip_prologue (gdbarch, amd64_windows_skip_prologue);

  set_gdbarch_auto_wide_charset (gdbarch, amd64_windows_auto_wide_charset);

  set_solib_ops (gdbarch, &solib_target_so_ops);
}

/* -Wmissing-prototypes */
extern initialize_file_ftype _initialize_amd64_windows_tdep;

void
_initialize_amd64_windows_tdep (void)
{
  gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64, GDB_OSABI_CYGWIN,
                          amd64_windows_init_abi);
}