1 //===-- EmulateInstruction.cpp --------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "lldb/Core/EmulateInstruction.h"
10
11 #include "lldb/Core/Address.h"
12 #include "lldb/Core/DumpRegisterValue.h"
13 #include "lldb/Core/PluginManager.h"
14 #include "lldb/Core/StreamFile.h"
15 #include "lldb/Symbol/UnwindPlan.h"
16 #include "lldb/Target/Process.h"
17 #include "lldb/Target/RegisterContext.h"
18 #include "lldb/Target/StackFrame.h"
19 #include "lldb/Utility/ConstString.h"
20 #include "lldb/Utility/DataExtractor.h"
21 #include "lldb/Utility/RegisterValue.h"
22 #include "lldb/Utility/Status.h"
23 #include "lldb/Utility/Stream.h"
24 #include "lldb/Utility/StreamString.h"
25 #include "lldb/lldb-forward.h"
26 #include "lldb/lldb-private-interfaces.h"
27
28 #include "llvm/ADT/StringRef.h"
29
30 #include <cstring>
31 #include <memory>
32
33 #include <inttypes.h>
34 #include <stdio.h>
35
36 namespace lldb_private {
37 class Target;
38 }
39
40 using namespace lldb;
41 using namespace lldb_private;
42
43 EmulateInstruction *
FindPlugin(const ArchSpec & arch,InstructionType supported_inst_type,const char * plugin_name)44 EmulateInstruction::FindPlugin(const ArchSpec &arch,
45 InstructionType supported_inst_type,
46 const char *plugin_name) {
47 EmulateInstructionCreateInstance create_callback = nullptr;
48 if (plugin_name) {
49 ConstString const_plugin_name(plugin_name);
50 create_callback =
51 PluginManager::GetEmulateInstructionCreateCallbackForPluginName(
52 const_plugin_name);
53 if (create_callback) {
54 EmulateInstruction *emulate_insn_ptr =
55 create_callback(arch, supported_inst_type);
56 if (emulate_insn_ptr)
57 return emulate_insn_ptr;
58 }
59 } else {
60 for (uint32_t idx = 0;
61 (create_callback =
62 PluginManager::GetEmulateInstructionCreateCallbackAtIndex(idx)) !=
63 nullptr;
64 ++idx) {
65 EmulateInstruction *emulate_insn_ptr =
66 create_callback(arch, supported_inst_type);
67 if (emulate_insn_ptr)
68 return emulate_insn_ptr;
69 }
70 }
71 return nullptr;
72 }
73
EmulateInstruction(const ArchSpec & arch)74 EmulateInstruction::EmulateInstruction(const ArchSpec &arch) : m_arch(arch) {}
75
ReadRegister(const RegisterInfo * reg_info,RegisterValue & reg_value)76 bool EmulateInstruction::ReadRegister(const RegisterInfo *reg_info,
77 RegisterValue ®_value) {
78 if (m_read_reg_callback != nullptr)
79 return m_read_reg_callback(this, m_baton, reg_info, reg_value);
80 return false;
81 }
82
ReadRegister(lldb::RegisterKind reg_kind,uint32_t reg_num,RegisterValue & reg_value)83 bool EmulateInstruction::ReadRegister(lldb::RegisterKind reg_kind,
84 uint32_t reg_num,
85 RegisterValue ®_value) {
86 RegisterInfo reg_info;
87 if (GetRegisterInfo(reg_kind, reg_num, reg_info))
88 return ReadRegister(®_info, reg_value);
89 return false;
90 }
91
ReadRegisterUnsigned(lldb::RegisterKind reg_kind,uint32_t reg_num,uint64_t fail_value,bool * success_ptr)92 uint64_t EmulateInstruction::ReadRegisterUnsigned(lldb::RegisterKind reg_kind,
93 uint32_t reg_num,
94 uint64_t fail_value,
95 bool *success_ptr) {
96 RegisterValue reg_value;
97 if (ReadRegister(reg_kind, reg_num, reg_value))
98 return reg_value.GetAsUInt64(fail_value, success_ptr);
99 if (success_ptr)
100 *success_ptr = false;
101 return fail_value;
102 }
103
ReadRegisterUnsigned(const RegisterInfo * reg_info,uint64_t fail_value,bool * success_ptr)104 uint64_t EmulateInstruction::ReadRegisterUnsigned(const RegisterInfo *reg_info,
105 uint64_t fail_value,
106 bool *success_ptr) {
107 RegisterValue reg_value;
108 if (ReadRegister(reg_info, reg_value))
109 return reg_value.GetAsUInt64(fail_value, success_ptr);
110 if (success_ptr)
111 *success_ptr = false;
112 return fail_value;
113 }
114
WriteRegister(const Context & context,const RegisterInfo * reg_info,const RegisterValue & reg_value)115 bool EmulateInstruction::WriteRegister(const Context &context,
116 const RegisterInfo *reg_info,
117 const RegisterValue ®_value) {
118 if (m_write_reg_callback != nullptr)
119 return m_write_reg_callback(this, m_baton, context, reg_info, reg_value);
120 return false;
121 }
122
WriteRegister(const Context & context,lldb::RegisterKind reg_kind,uint32_t reg_num,const RegisterValue & reg_value)123 bool EmulateInstruction::WriteRegister(const Context &context,
124 lldb::RegisterKind reg_kind,
125 uint32_t reg_num,
126 const RegisterValue ®_value) {
127 RegisterInfo reg_info;
128 if (GetRegisterInfo(reg_kind, reg_num, reg_info))
129 return WriteRegister(context, ®_info, reg_value);
130 return false;
131 }
132
WriteRegisterUnsigned(const Context & context,lldb::RegisterKind reg_kind,uint32_t reg_num,uint64_t uint_value)133 bool EmulateInstruction::WriteRegisterUnsigned(const Context &context,
134 lldb::RegisterKind reg_kind,
135 uint32_t reg_num,
136 uint64_t uint_value) {
137 RegisterInfo reg_info;
138 if (GetRegisterInfo(reg_kind, reg_num, reg_info)) {
139 RegisterValue reg_value;
140 if (reg_value.SetUInt(uint_value, reg_info.byte_size))
141 return WriteRegister(context, ®_info, reg_value);
142 }
143 return false;
144 }
145
WriteRegisterUnsigned(const Context & context,const RegisterInfo * reg_info,uint64_t uint_value)146 bool EmulateInstruction::WriteRegisterUnsigned(const Context &context,
147 const RegisterInfo *reg_info,
148 uint64_t uint_value) {
149 if (reg_info != nullptr) {
150 RegisterValue reg_value;
151 if (reg_value.SetUInt(uint_value, reg_info->byte_size))
152 return WriteRegister(context, reg_info, reg_value);
153 }
154 return false;
155 }
156
ReadMemory(const Context & context,lldb::addr_t addr,void * dst,size_t dst_len)157 size_t EmulateInstruction::ReadMemory(const Context &context, lldb::addr_t addr,
158 void *dst, size_t dst_len) {
159 if (m_read_mem_callback != nullptr)
160 return m_read_mem_callback(this, m_baton, context, addr, dst, dst_len) ==
161 dst_len;
162 return false;
163 }
164
ReadMemoryUnsigned(const Context & context,lldb::addr_t addr,size_t byte_size,uint64_t fail_value,bool * success_ptr)165 uint64_t EmulateInstruction::ReadMemoryUnsigned(const Context &context,
166 lldb::addr_t addr,
167 size_t byte_size,
168 uint64_t fail_value,
169 bool *success_ptr) {
170 uint64_t uval64 = 0;
171 bool success = false;
172 if (byte_size <= 8) {
173 uint8_t buf[sizeof(uint64_t)];
174 size_t bytes_read =
175 m_read_mem_callback(this, m_baton, context, addr, buf, byte_size);
176 if (bytes_read == byte_size) {
177 lldb::offset_t offset = 0;
178 DataExtractor data(buf, byte_size, GetByteOrder(), GetAddressByteSize());
179 uval64 = data.GetMaxU64(&offset, byte_size);
180 success = true;
181 }
182 }
183
184 if (success_ptr)
185 *success_ptr = success;
186
187 if (!success)
188 uval64 = fail_value;
189 return uval64;
190 }
191
WriteMemoryUnsigned(const Context & context,lldb::addr_t addr,uint64_t uval,size_t uval_byte_size)192 bool EmulateInstruction::WriteMemoryUnsigned(const Context &context,
193 lldb::addr_t addr, uint64_t uval,
194 size_t uval_byte_size) {
195 StreamString strm(Stream::eBinary, GetAddressByteSize(), GetByteOrder());
196 strm.PutMaxHex64(uval, uval_byte_size);
197
198 size_t bytes_written = m_write_mem_callback(
199 this, m_baton, context, addr, strm.GetString().data(), uval_byte_size);
200 return (bytes_written == uval_byte_size);
201 }
202
WriteMemory(const Context & context,lldb::addr_t addr,const void * src,size_t src_len)203 bool EmulateInstruction::WriteMemory(const Context &context, lldb::addr_t addr,
204 const void *src, size_t src_len) {
205 if (m_write_mem_callback != nullptr)
206 return m_write_mem_callback(this, m_baton, context, addr, src, src_len) ==
207 src_len;
208 return false;
209 }
210
SetBaton(void * baton)211 void EmulateInstruction::SetBaton(void *baton) { m_baton = baton; }
212
SetCallbacks(ReadMemoryCallback read_mem_callback,WriteMemoryCallback write_mem_callback,ReadRegisterCallback read_reg_callback,WriteRegisterCallback write_reg_callback)213 void EmulateInstruction::SetCallbacks(
214 ReadMemoryCallback read_mem_callback,
215 WriteMemoryCallback write_mem_callback,
216 ReadRegisterCallback read_reg_callback,
217 WriteRegisterCallback write_reg_callback) {
218 m_read_mem_callback = read_mem_callback;
219 m_write_mem_callback = write_mem_callback;
220 m_read_reg_callback = read_reg_callback;
221 m_write_reg_callback = write_reg_callback;
222 }
223
SetReadMemCallback(ReadMemoryCallback read_mem_callback)224 void EmulateInstruction::SetReadMemCallback(
225 ReadMemoryCallback read_mem_callback) {
226 m_read_mem_callback = read_mem_callback;
227 }
228
SetWriteMemCallback(WriteMemoryCallback write_mem_callback)229 void EmulateInstruction::SetWriteMemCallback(
230 WriteMemoryCallback write_mem_callback) {
231 m_write_mem_callback = write_mem_callback;
232 }
233
SetReadRegCallback(ReadRegisterCallback read_reg_callback)234 void EmulateInstruction::SetReadRegCallback(
235 ReadRegisterCallback read_reg_callback) {
236 m_read_reg_callback = read_reg_callback;
237 }
238
SetWriteRegCallback(WriteRegisterCallback write_reg_callback)239 void EmulateInstruction::SetWriteRegCallback(
240 WriteRegisterCallback write_reg_callback) {
241 m_write_reg_callback = write_reg_callback;
242 }
243
244 //
245 // Read & Write Memory and Registers callback functions.
246 //
247
ReadMemoryFrame(EmulateInstruction * instruction,void * baton,const Context & context,lldb::addr_t addr,void * dst,size_t dst_len)248 size_t EmulateInstruction::ReadMemoryFrame(EmulateInstruction *instruction,
249 void *baton, const Context &context,
250 lldb::addr_t addr, void *dst,
251 size_t dst_len) {
252 if (baton == nullptr || dst == nullptr || dst_len == 0)
253 return 0;
254
255 StackFrame *frame = (StackFrame *)baton;
256
257 ProcessSP process_sp(frame->CalculateProcess());
258 if (process_sp) {
259 Status error;
260 return process_sp->ReadMemory(addr, dst, dst_len, error);
261 }
262 return 0;
263 }
264
WriteMemoryFrame(EmulateInstruction * instruction,void * baton,const Context & context,lldb::addr_t addr,const void * src,size_t src_len)265 size_t EmulateInstruction::WriteMemoryFrame(EmulateInstruction *instruction,
266 void *baton, const Context &context,
267 lldb::addr_t addr, const void *src,
268 size_t src_len) {
269 if (baton == nullptr || src == nullptr || src_len == 0)
270 return 0;
271
272 StackFrame *frame = (StackFrame *)baton;
273
274 ProcessSP process_sp(frame->CalculateProcess());
275 if (process_sp) {
276 Status error;
277 return process_sp->WriteMemory(addr, src, src_len, error);
278 }
279
280 return 0;
281 }
282
ReadRegisterFrame(EmulateInstruction * instruction,void * baton,const RegisterInfo * reg_info,RegisterValue & reg_value)283 bool EmulateInstruction::ReadRegisterFrame(EmulateInstruction *instruction,
284 void *baton,
285 const RegisterInfo *reg_info,
286 RegisterValue ®_value) {
287 if (baton == nullptr)
288 return false;
289
290 StackFrame *frame = (StackFrame *)baton;
291 return frame->GetRegisterContext()->ReadRegister(reg_info, reg_value);
292 }
293
WriteRegisterFrame(EmulateInstruction * instruction,void * baton,const Context & context,const RegisterInfo * reg_info,const RegisterValue & reg_value)294 bool EmulateInstruction::WriteRegisterFrame(EmulateInstruction *instruction,
295 void *baton, const Context &context,
296 const RegisterInfo *reg_info,
297 const RegisterValue ®_value) {
298 if (baton == nullptr)
299 return false;
300
301 StackFrame *frame = (StackFrame *)baton;
302 return frame->GetRegisterContext()->WriteRegister(reg_info, reg_value);
303 }
304
ReadMemoryDefault(EmulateInstruction * instruction,void * baton,const Context & context,lldb::addr_t addr,void * dst,size_t length)305 size_t EmulateInstruction::ReadMemoryDefault(EmulateInstruction *instruction,
306 void *baton,
307 const Context &context,
308 lldb::addr_t addr, void *dst,
309 size_t length) {
310 StreamFile strm(stdout, false);
311 strm.Printf(" Read from Memory (address = 0x%" PRIx64 ", length = %" PRIu64
312 ", context = ",
313 addr, (uint64_t)length);
314 context.Dump(strm, instruction);
315 strm.EOL();
316 *((uint64_t *)dst) = 0xdeadbeef;
317 return length;
318 }
319
WriteMemoryDefault(EmulateInstruction * instruction,void * baton,const Context & context,lldb::addr_t addr,const void * dst,size_t length)320 size_t EmulateInstruction::WriteMemoryDefault(EmulateInstruction *instruction,
321 void *baton,
322 const Context &context,
323 lldb::addr_t addr,
324 const void *dst, size_t length) {
325 StreamFile strm(stdout, false);
326 strm.Printf(" Write to Memory (address = 0x%" PRIx64 ", length = %" PRIu64
327 ", context = ",
328 addr, (uint64_t)length);
329 context.Dump(strm, instruction);
330 strm.EOL();
331 return length;
332 }
333
ReadRegisterDefault(EmulateInstruction * instruction,void * baton,const RegisterInfo * reg_info,RegisterValue & reg_value)334 bool EmulateInstruction::ReadRegisterDefault(EmulateInstruction *instruction,
335 void *baton,
336 const RegisterInfo *reg_info,
337 RegisterValue ®_value) {
338 StreamFile strm(stdout, false);
339 strm.Printf(" Read Register (%s)\n", reg_info->name);
340 lldb::RegisterKind reg_kind;
341 uint32_t reg_num;
342 if (GetBestRegisterKindAndNumber(reg_info, reg_kind, reg_num))
343 reg_value.SetUInt64((uint64_t)reg_kind << 24 | reg_num);
344 else
345 reg_value.SetUInt64(0);
346
347 return true;
348 }
349
WriteRegisterDefault(EmulateInstruction * instruction,void * baton,const Context & context,const RegisterInfo * reg_info,const RegisterValue & reg_value)350 bool EmulateInstruction::WriteRegisterDefault(EmulateInstruction *instruction,
351 void *baton,
352 const Context &context,
353 const RegisterInfo *reg_info,
354 const RegisterValue ®_value) {
355 StreamFile strm(stdout, false);
356 strm.Printf(" Write to Register (name = %s, value = ", reg_info->name);
357 DumpRegisterValue(reg_value, &strm, reg_info, false, false, eFormatDefault);
358 strm.PutCString(", context = ");
359 context.Dump(strm, instruction);
360 strm.EOL();
361 return true;
362 }
363
Dump(Stream & strm,EmulateInstruction * instruction) const364 void EmulateInstruction::Context::Dump(Stream &strm,
365 EmulateInstruction *instruction) const {
366 switch (type) {
367 case eContextReadOpcode:
368 strm.PutCString("reading opcode");
369 break;
370
371 case eContextImmediate:
372 strm.PutCString("immediate");
373 break;
374
375 case eContextPushRegisterOnStack:
376 strm.PutCString("push register");
377 break;
378
379 case eContextPopRegisterOffStack:
380 strm.PutCString("pop register");
381 break;
382
383 case eContextAdjustStackPointer:
384 strm.PutCString("adjust sp");
385 break;
386
387 case eContextSetFramePointer:
388 strm.PutCString("set frame pointer");
389 break;
390
391 case eContextAdjustBaseRegister:
392 strm.PutCString("adjusting (writing value back to) a base register");
393 break;
394
395 case eContextRegisterPlusOffset:
396 strm.PutCString("register + offset");
397 break;
398
399 case eContextRegisterStore:
400 strm.PutCString("store register");
401 break;
402
403 case eContextRegisterLoad:
404 strm.PutCString("load register");
405 break;
406
407 case eContextRelativeBranchImmediate:
408 strm.PutCString("relative branch immediate");
409 break;
410
411 case eContextAbsoluteBranchRegister:
412 strm.PutCString("absolute branch register");
413 break;
414
415 case eContextSupervisorCall:
416 strm.PutCString("supervisor call");
417 break;
418
419 case eContextTableBranchReadMemory:
420 strm.PutCString("table branch read memory");
421 break;
422
423 case eContextWriteRegisterRandomBits:
424 strm.PutCString("write random bits to a register");
425 break;
426
427 case eContextWriteMemoryRandomBits:
428 strm.PutCString("write random bits to a memory address");
429 break;
430
431 case eContextArithmetic:
432 strm.PutCString("arithmetic");
433 break;
434
435 case eContextReturnFromException:
436 strm.PutCString("return from exception");
437 break;
438
439 default:
440 strm.PutCString("unrecognized context.");
441 break;
442 }
443
444 switch (info_type) {
445 case eInfoTypeRegisterPlusOffset:
446 strm.Printf(" (reg_plus_offset = %s%+" PRId64 ")",
447 info.RegisterPlusOffset.reg.name,
448 info.RegisterPlusOffset.signed_offset);
449 break;
450
451 case eInfoTypeRegisterPlusIndirectOffset:
452 strm.Printf(" (reg_plus_reg = %s + %s)",
453 info.RegisterPlusIndirectOffset.base_reg.name,
454 info.RegisterPlusIndirectOffset.offset_reg.name);
455 break;
456
457 case eInfoTypeRegisterToRegisterPlusOffset:
458 strm.Printf(" (base_and_imm_offset = %s%+" PRId64 ", data_reg = %s)",
459 info.RegisterToRegisterPlusOffset.base_reg.name,
460 info.RegisterToRegisterPlusOffset.offset,
461 info.RegisterToRegisterPlusOffset.data_reg.name);
462 break;
463
464 case eInfoTypeRegisterToRegisterPlusIndirectOffset:
465 strm.Printf(" (base_and_reg_offset = %s + %s, data_reg = %s)",
466 info.RegisterToRegisterPlusIndirectOffset.base_reg.name,
467 info.RegisterToRegisterPlusIndirectOffset.offset_reg.name,
468 info.RegisterToRegisterPlusIndirectOffset.data_reg.name);
469 break;
470
471 case eInfoTypeRegisterRegisterOperands:
472 strm.Printf(" (register to register binary op: %s and %s)",
473 info.RegisterRegisterOperands.operand1.name,
474 info.RegisterRegisterOperands.operand2.name);
475 break;
476
477 case eInfoTypeOffset:
478 strm.Printf(" (signed_offset = %+" PRId64 ")", info.signed_offset);
479 break;
480
481 case eInfoTypeRegister:
482 strm.Printf(" (reg = %s)", info.reg.name);
483 break;
484
485 case eInfoTypeImmediate:
486 strm.Printf(" (unsigned_immediate = %" PRIu64 " (0x%16.16" PRIx64 "))",
487 info.unsigned_immediate, info.unsigned_immediate);
488 break;
489
490 case eInfoTypeImmediateSigned:
491 strm.Printf(" (signed_immediate = %+" PRId64 " (0x%16.16" PRIx64 "))",
492 info.signed_immediate, info.signed_immediate);
493 break;
494
495 case eInfoTypeAddress:
496 strm.Printf(" (address = 0x%" PRIx64 ")", info.address);
497 break;
498
499 case eInfoTypeISAAndImmediate:
500 strm.Printf(" (isa = %u, unsigned_immediate = %u (0x%8.8x))",
501 info.ISAAndImmediate.isa, info.ISAAndImmediate.unsigned_data32,
502 info.ISAAndImmediate.unsigned_data32);
503 break;
504
505 case eInfoTypeISAAndImmediateSigned:
506 strm.Printf(" (isa = %u, signed_immediate = %i (0x%8.8x))",
507 info.ISAAndImmediateSigned.isa,
508 info.ISAAndImmediateSigned.signed_data32,
509 info.ISAAndImmediateSigned.signed_data32);
510 break;
511
512 case eInfoTypeISA:
513 strm.Printf(" (isa = %u)", info.isa);
514 break;
515
516 case eInfoTypeNoArgs:
517 break;
518 }
519 }
520
SetInstruction(const Opcode & opcode,const Address & inst_addr,Target * target)521 bool EmulateInstruction::SetInstruction(const Opcode &opcode,
522 const Address &inst_addr,
523 Target *target) {
524 m_opcode = opcode;
525 m_addr = LLDB_INVALID_ADDRESS;
526 if (inst_addr.IsValid()) {
527 if (target != nullptr)
528 m_addr = inst_addr.GetLoadAddress(target);
529 if (m_addr == LLDB_INVALID_ADDRESS)
530 m_addr = inst_addr.GetFileAddress();
531 }
532 return true;
533 }
534
GetBestRegisterKindAndNumber(const RegisterInfo * reg_info,lldb::RegisterKind & reg_kind,uint32_t & reg_num)535 bool EmulateInstruction::GetBestRegisterKindAndNumber(
536 const RegisterInfo *reg_info, lldb::RegisterKind ®_kind,
537 uint32_t ®_num) {
538 // Generic and DWARF should be the two most popular register kinds when
539 // emulating instructions since they are the most platform agnostic...
540 reg_num = reg_info->kinds[eRegisterKindGeneric];
541 if (reg_num != LLDB_INVALID_REGNUM) {
542 reg_kind = eRegisterKindGeneric;
543 return true;
544 }
545
546 reg_num = reg_info->kinds[eRegisterKindDWARF];
547 if (reg_num != LLDB_INVALID_REGNUM) {
548 reg_kind = eRegisterKindDWARF;
549 return true;
550 }
551
552 reg_num = reg_info->kinds[eRegisterKindLLDB];
553 if (reg_num != LLDB_INVALID_REGNUM) {
554 reg_kind = eRegisterKindLLDB;
555 return true;
556 }
557
558 reg_num = reg_info->kinds[eRegisterKindEHFrame];
559 if (reg_num != LLDB_INVALID_REGNUM) {
560 reg_kind = eRegisterKindEHFrame;
561 return true;
562 }
563
564 reg_num = reg_info->kinds[eRegisterKindProcessPlugin];
565 if (reg_num != LLDB_INVALID_REGNUM) {
566 reg_kind = eRegisterKindProcessPlugin;
567 return true;
568 }
569 return false;
570 }
571
572 uint32_t
GetInternalRegisterNumber(RegisterContext * reg_ctx,const RegisterInfo & reg_info)573 EmulateInstruction::GetInternalRegisterNumber(RegisterContext *reg_ctx,
574 const RegisterInfo ®_info) {
575 lldb::RegisterKind reg_kind;
576 uint32_t reg_num;
577 if (reg_ctx && GetBestRegisterKindAndNumber(®_info, reg_kind, reg_num))
578 return reg_ctx->ConvertRegisterKindToRegisterNumber(reg_kind, reg_num);
579 return LLDB_INVALID_REGNUM;
580 }
581
CreateFunctionEntryUnwind(UnwindPlan & unwind_plan)582 bool EmulateInstruction::CreateFunctionEntryUnwind(UnwindPlan &unwind_plan) {
583 unwind_plan.Clear();
584 return false;
585 }
586