1 //===-- UnwindAssemblyInstEmulation.cpp --------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "UnwindAssemblyInstEmulation.h"
11 
12 #include "llvm-c/EnhancedDisassembly.h"
13 
14 #include "lldb/Core/Address.h"
15 #include "lldb/Core/ArchSpec.h"
16 #include "lldb/Core/DataBufferHeap.h"
17 #include "lldb/Core/DataExtractor.h"
18 #include "lldb/Core/Disassembler.h"
19 #include "lldb/Core/Error.h"
20 #include "lldb/Core/Log.h"
21 #include "lldb/Core/PluginManager.h"
22 #include "lldb/Core/StreamString.h"
23 #include "lldb/Target/ExecutionContext.h"
24 #include "lldb/Target/Process.h"
25 #include "lldb/Target/Thread.h"
26 #include "lldb/Target/Target.h"
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 
31 
32 
33 //-----------------------------------------------------------------------------------------------
34 //  UnwindAssemblyInstEmulation method definitions
35 //-----------------------------------------------------------------------------------------------
36 
37 bool
38 UnwindAssemblyInstEmulation::GetNonCallSiteUnwindPlanFromAssembly (AddressRange& range,
39                                                                    Thread& thread,
40                                                                    UnwindPlan& unwind_plan)
41 {
42     if (range.GetByteSize() > 0 &&
43         range.GetBaseAddress().IsValid() &&
44         m_inst_emulator_ap.get())
45     {
46 
47         // The the instruction emulation subclass setup the unwind plan for the
48         // first instruction.
49         m_inst_emulator_ap->CreateFunctionEntryUnwind (unwind_plan);
50 
51         // CreateFunctionEntryUnwind should have created the first row. If it
52         // doesn't, then we are done.
53         if (unwind_plan.GetRowCount() == 0)
54             return false;
55 
56         ExecutionContext exe_ctx;
57         thread.CalculateExecutionContext(exe_ctx);
58         DisassemblerSP disasm_sp (Disassembler::DisassembleRange (m_arch,
59                                                                   NULL,
60                                                                   exe_ctx,
61                                                                   range));
62 
63         LogSP log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
64 
65         if (disasm_sp)
66         {
67 
68             m_range_ptr = ⦥
69             m_thread_ptr = &thread;
70             m_unwind_plan_ptr = &unwind_plan;
71 
72             const uint32_t addr_byte_size = m_arch.GetAddressByteSize();
73             const bool show_address = true;
74             const bool show_bytes = true;
75             m_inst_emulator_ap->GetRegisterInfo (unwind_plan.GetRegisterKind(),
76                                                  unwind_plan.GetInitialCFARegister(),
77                                                  m_cfa_reg_info);
78 
79             m_fp_is_cfa = false;
80             m_register_values.clear();
81             m_pushed_regs.clear();
82 
83             // Initialize the CFA with a known value. In the 32 bit case
84             // it will be 0x80000000, and in the 64 bit case 0x8000000000000000.
85             // We use the address byte size to be safe for any future addresss sizes
86             m_initial_sp = (1ull << ((addr_byte_size * 8) - 1));
87             RegisterValue cfa_reg_value;
88             cfa_reg_value.SetUInt (m_initial_sp, m_cfa_reg_info.byte_size);
89             SetRegisterValue (m_cfa_reg_info, cfa_reg_value);
90 
91             const InstructionList &inst_list = disasm_sp->GetInstructionList ();
92             const size_t num_instructions = inst_list.GetSize();
93 
94             if (num_instructions > 0)
95             {
96                 Instruction *inst = inst_list.GetInstructionAtIndex (0).get();
97                 const addr_t base_addr = inst->GetAddress().GetFileAddress();
98 
99                 // Make a copy of the current instruction Row and save it in m_curr_row
100                 // so we can add updates as we process the instructions.
101                 UnwindPlan::RowSP last_row = unwind_plan.GetLastRow();
102                 UnwindPlan::Row *newrow = new UnwindPlan::Row;
103                 if (last_row.get())
104                     *newrow = *last_row.get();
105                 m_curr_row.reset(newrow);
106 
107                 // Once we've seen the initial prologue instructions complete, save a
108                 // copy of the CFI at that point into prologue_completed_row for possible
109                 // use later.
110                 int instructions_since_last_prologue_insn = 0;     // # of insns since last CFI was update
111 
112                 bool reinstate_prologue_next_instruction = false;  // Next iteration, re-install the prologue row of CFI
113 
114                 bool last_instruction_restored_return_addr_reg = false;  // re-install the prologue row of CFI if the next instruction is a branch immediate
115 
116                 bool return_address_register_has_been_saved = false; // if we've seen the ra register get saved yet
117 
118                 UnwindPlan::RowSP prologue_completed_row;          // copy of prologue row of CFI
119 
120                 // cache the pc register number (in whatever register numbering this UnwindPlan uses) for
121                 // quick reference during instruction parsing.
122                 uint32_t pc_reg_num = LLDB_INVALID_REGNUM;
123                 RegisterInfo pc_reg_info;
124                 if (m_inst_emulator_ap->GetRegisterInfo (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC, pc_reg_info))
125                     pc_reg_num = pc_reg_info.kinds[unwind_plan.GetRegisterKind()];
126                 else
127                     pc_reg_num = LLDB_INVALID_REGNUM;
128 
129                 // cache the return address register number (in whatever register numbering this UnwindPlan uses) for
130                 // quick reference during instruction parsing.
131                 uint32_t ra_reg_num = LLDB_INVALID_REGNUM;
132                 RegisterInfo ra_reg_info;
133                 if (m_inst_emulator_ap->GetRegisterInfo (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_RA, ra_reg_info))
134                     ra_reg_num = ra_reg_info.kinds[unwind_plan.GetRegisterKind()];
135                 else
136                     ra_reg_num = LLDB_INVALID_REGNUM;
137 
138                 for (size_t idx=0; idx<num_instructions; ++idx)
139                 {
140                     m_curr_row_modified = false;
141                     m_curr_insn_restored_a_register = false;
142                     inst = inst_list.GetInstructionAtIndex (idx).get();
143                     if (inst)
144                     {
145                         if (log && log->GetVerbose ())
146                         {
147                             StreamString strm;
148                             inst->Dump(&strm, inst_list.GetMaxOpcocdeByteSize (), show_address, show_bytes, NULL);
149                             log->PutCString (strm.GetData());
150                         }
151 
152                         m_inst_emulator_ap->SetInstruction (inst->GetOpcode(),
153                                                             inst->GetAddress(),
154                                                             exe_ctx.GetTargetPtr());
155 
156                         m_inst_emulator_ap->EvaluateInstruction (eEmulateInstructionOptionIgnoreConditions);
157 
158                         // Were there any changes to the CFI while evaluating this instruction?
159                         if (m_curr_row_modified)
160                         {
161                             reinstate_prologue_next_instruction = false;
162                             m_curr_row->SetOffset (inst->GetAddress().GetFileAddress() + inst->GetOpcode().GetByteSize() - base_addr);
163                             // Append the new row
164                             unwind_plan.AppendRow (m_curr_row);
165 
166                             // Allocate a new Row for m_curr_row, copy the current state into it
167                             UnwindPlan::Row *newrow = new UnwindPlan::Row;
168                             *newrow = *m_curr_row.get();
169                             m_curr_row.reset(newrow);
170 
171                             // If m_curr_insn_restored_a_register == true, we're looking at an epilogue instruction.
172                             // Set instructions_since_last_prologue_insn to a very high number so we don't append
173                             // any of these epilogue instructions to our prologue_complete row.
174                             if (m_curr_insn_restored_a_register == false && instructions_since_last_prologue_insn < 8)
175                               instructions_since_last_prologue_insn = 0;
176                             else
177                               instructions_since_last_prologue_insn = 99;
178 
179                             UnwindPlan::Row::RegisterLocation pc_regloc;
180                             UnwindPlan::Row::RegisterLocation ra_regloc;
181 
182                             // While parsing the instructions of this function, if we've ever
183                             // seen the return address register (aka lr on arm) in a non-IsSame() state,
184                             // it has been saved on the stack.  If it's evern back to IsSame(), we've
185                             // executed an epilogue.
186                             if (ra_reg_num != LLDB_INVALID_REGNUM
187                                 && m_curr_row->GetRegisterInfo (ra_reg_num, ra_regloc)
188                                 && !ra_regloc.IsSame())
189                             {
190                                 return_address_register_has_been_saved = true;
191                             }
192 
193                             // If the caller's pc is "same", we've just executed an epilogue and we return to the caller
194                             // after this instruction completes executing.
195                             // If there are any instructions past this, there must have been flow control over this
196                             // epilogue so we'll reinstate the original prologue setup instructions.
197                             if (prologue_completed_row.get()
198                                 && pc_reg_num != LLDB_INVALID_REGNUM
199                                 && m_curr_row->GetRegisterInfo (pc_reg_num, pc_regloc)
200                                 && pc_regloc.IsSame())
201                             {
202                                 if (log && log->GetVerbose())
203                                     log->Printf("UnwindAssemblyInstEmulation::GetNonCallSiteUnwindPlanFromAssembly -- pc is <same>, restore prologue instructions.");
204                                 reinstate_prologue_next_instruction = true;
205                             }
206                             else if (prologue_completed_row.get()
207                                      && return_address_register_has_been_saved
208                                      && ra_reg_num != LLDB_INVALID_REGNUM
209                                      && m_curr_row->GetRegisterInfo (ra_reg_num, ra_regloc)
210                                      && ra_regloc.IsSame())
211                             {
212                                 if (log && log->GetVerbose())
213                                     log->Printf("UnwindAssemblyInstEmulation::GetNonCallSiteUnwindPlanFromAssembly -- lr is <same>, restore prologue instruction if the next instruction is a branch immediate.");
214                                 last_instruction_restored_return_addr_reg = true;
215                             }
216                         }
217                         else
218                         {
219                             // If the previous instruction was a return-to-caller (epilogue), and we're still executing
220                             // instructions in this function, there must be a code path that jumps over that epilogue.
221                             // Also detect the case where we epilogue & branch imm to another function (tail-call opt)
222                             // instead of a normal pop lr-into-pc exit.
223                             // Reinstate the frame setup from the prologue.
224                             if (reinstate_prologue_next_instruction
225                                 || (m_curr_insn_is_branch_immediate && last_instruction_restored_return_addr_reg))
226                             {
227                                 if (log && log->GetVerbose())
228                                     log->Printf("UnwindAssemblyInstEmulation::GetNonCallSiteUnwindPlanFromAssembly -- Reinstating prologue instruction set");
229                                 UnwindPlan::Row *newrow = new UnwindPlan::Row;
230                                 *newrow = *prologue_completed_row.get();
231                                 m_curr_row.reset(newrow);
232                                 m_curr_row->SetOffset (inst->GetAddress().GetFileAddress() + inst->GetOpcode().GetByteSize() - base_addr);
233                                 unwind_plan.AppendRow(m_curr_row);
234 
235                                 newrow = new UnwindPlan::Row;
236                                 *newrow = *m_curr_row.get();
237                                 m_curr_row.reset(newrow);
238 
239                                 reinstate_prologue_next_instruction = false;
240                                 last_instruction_restored_return_addr_reg = false;
241                                 m_curr_insn_is_branch_immediate = false;
242                             }
243 
244                             // clear both of these if either one wasn't set
245                             if (last_instruction_restored_return_addr_reg)
246                             {
247                                 last_instruction_restored_return_addr_reg = false;
248                             }
249                             if (m_curr_insn_is_branch_immediate)
250                             {
251                                 m_curr_insn_is_branch_immediate = false;
252                             }
253 
254                             // Stop updating the prologue instructions if we've seen 8 non-prologue instructions
255                             // in a row.
256                             if (instructions_since_last_prologue_insn++ < 8)
257                             {
258                                 UnwindPlan::Row *newrow = new UnwindPlan::Row;
259                                 *newrow = *m_curr_row.get();
260                                 prologue_completed_row.reset(newrow);
261                                 if (log && log->GetVerbose())
262                                     log->Printf("UnwindAssemblyInstEmulation::GetNonCallSiteUnwindPlanFromAssembly -- saving a copy of the current row as the prologue row.");
263                             }
264                         }
265                     }
266                 }
267             }
268         }
269 
270         if (log && log->GetVerbose ())
271         {
272             StreamString strm;
273             lldb::addr_t base_addr = range.GetBaseAddress().GetLoadAddress(thread.CalculateTarget().get());
274             strm.Printf ("Resulting unwind rows for [0x%llx - 0x%llx):", base_addr, base_addr + range.GetByteSize());
275             unwind_plan.Dump(strm, &thread, base_addr);
276             log->PutCString (strm.GetData());
277         }
278         return unwind_plan.GetRowCount() > 0;
279     }
280     return false;
281 }
282 
283 bool
284 UnwindAssemblyInstEmulation::GetFastUnwindPlan (AddressRange& func,
285                                                 Thread& thread,
286                                                 UnwindPlan &unwind_plan)
287 {
288     return false;
289 }
290 
291 bool
292 UnwindAssemblyInstEmulation::FirstNonPrologueInsn (AddressRange& func,
293                                                    const ExecutionContext &exe_ctx,
294                                                    Address& first_non_prologue_insn)
295 {
296     return false;
297 }
298 
299 UnwindAssembly *
300 UnwindAssemblyInstEmulation::CreateInstance (const ArchSpec &arch)
301 {
302     std::auto_ptr<EmulateInstruction> inst_emulator_ap (EmulateInstruction::FindPlugin (arch, eInstructionTypePrologueEpilogue, NULL));
303     // Make sure that all prologue instructions are handled
304     if (inst_emulator_ap.get())
305         return new UnwindAssemblyInstEmulation (arch, inst_emulator_ap.release());
306     return NULL;
307 }
308 
309 
310 //------------------------------------------------------------------
311 // PluginInterface protocol in UnwindAssemblyParser_x86
312 //------------------------------------------------------------------
313 
314 const char *
315 UnwindAssemblyInstEmulation::GetPluginName()
316 {
317     return "UnwindAssemblyInstEmulation";
318 }
319 
320 const char *
321 UnwindAssemblyInstEmulation::GetShortPluginName()
322 {
323     return "unwindassembly.inst-emulation";
324 }
325 
326 
327 uint32_t
328 UnwindAssemblyInstEmulation::GetPluginVersion()
329 {
330     return 1;
331 }
332 
333 void
334 UnwindAssemblyInstEmulation::Initialize()
335 {
336     PluginManager::RegisterPlugin (GetPluginNameStatic(),
337                                    GetPluginDescriptionStatic(),
338                                    CreateInstance);
339 }
340 
341 void
342 UnwindAssemblyInstEmulation::Terminate()
343 {
344     PluginManager::UnregisterPlugin (CreateInstance);
345 }
346 
347 
348 const char *
349 UnwindAssemblyInstEmulation::GetPluginNameStatic()
350 {
351     return "UnwindAssemblyInstEmulation";
352 }
353 
354 const char *
355 UnwindAssemblyInstEmulation::GetPluginDescriptionStatic()
356 {
357     return "Instruction emulation based unwind information.";
358 }
359 
360 
361 uint64_t
362 UnwindAssemblyInstEmulation::MakeRegisterKindValuePair (const RegisterInfo &reg_info)
363 {
364     uint32_t reg_kind, reg_num;
365     if (EmulateInstruction::GetBestRegisterKindAndNumber (&reg_info, reg_kind, reg_num))
366         return (uint64_t)reg_kind << 24 | reg_num;
367     return 0ull;
368 }
369 
370 void
371 UnwindAssemblyInstEmulation::SetRegisterValue (const RegisterInfo &reg_info, const RegisterValue &reg_value)
372 {
373     m_register_values[MakeRegisterKindValuePair (reg_info)] = reg_value;
374 }
375 
376 bool
377 UnwindAssemblyInstEmulation::GetRegisterValue (const RegisterInfo &reg_info, RegisterValue &reg_value)
378 {
379     const uint64_t reg_id = MakeRegisterKindValuePair (reg_info);
380     RegisterValueMap::const_iterator pos = m_register_values.find(reg_id);
381     if (pos != m_register_values.end())
382     {
383         reg_value = pos->second;
384         return true; // We had a real value that comes from an opcode that wrote
385                      // to it...
386     }
387     // We are making up a value that is recognizable...
388     reg_value.SetUInt(reg_id, reg_info.byte_size);
389     return false;
390 }
391 
392 
393 size_t
394 UnwindAssemblyInstEmulation::ReadMemory (EmulateInstruction *instruction,
395                                          void *baton,
396                                          const EmulateInstruction::Context &context,
397                                          lldb::addr_t addr,
398                                          void *dst,
399                                          size_t dst_len)
400 {
401     LogSP log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
402 
403     if (log && log->GetVerbose ())
404     {
405         StreamString strm;
406         strm.Printf ("UnwindAssemblyInstEmulation::ReadMemory    (addr = 0x%16.16llx, dst = %p, dst_len = %llu, context = ",
407                      addr,
408                      dst,
409                      (uint64_t)dst_len);
410         context.Dump(strm, instruction);
411         log->PutCString (strm.GetData ());
412     }
413     memset (dst, 0, dst_len);
414     return dst_len;
415 }
416 
417 size_t
418 UnwindAssemblyInstEmulation::WriteMemory (EmulateInstruction *instruction,
419                                           void *baton,
420                                           const EmulateInstruction::Context &context,
421                                           lldb::addr_t addr,
422                                           const void *dst,
423                                           size_t dst_len)
424 {
425     if (baton && dst && dst_len)
426         return ((UnwindAssemblyInstEmulation *)baton)->WriteMemory (instruction, context, addr, dst, dst_len);
427     return 0;
428 }
429 
430 size_t
431 UnwindAssemblyInstEmulation::WriteMemory (EmulateInstruction *instruction,
432                                           const EmulateInstruction::Context &context,
433                                           lldb::addr_t addr,
434                                           const void *dst,
435                                           size_t dst_len)
436 {
437     DataExtractor data (dst,
438                         dst_len,
439                         instruction->GetArchitecture ().GetByteOrder(),
440                         instruction->GetArchitecture ().GetAddressByteSize());
441 
442     LogSP log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
443 
444     if (log && log->GetVerbose ())
445     {
446         StreamString strm;
447 
448         strm.PutCString ("UnwindAssemblyInstEmulation::WriteMemory   (");
449         data.Dump(&strm, 0, eFormatBytes, 1, dst_len, UINT32_MAX, addr, 0, 0);
450         strm.PutCString (", context = ");
451         context.Dump(strm, instruction);
452         log->PutCString (strm.GetData());
453     }
454 
455     const bool can_replace = true;
456     const bool cant_replace = false;
457 
458     switch (context.type)
459     {
460         default:
461         case EmulateInstruction::eContextInvalid:
462         case EmulateInstruction::eContextReadOpcode:
463         case EmulateInstruction::eContextImmediate:
464         case EmulateInstruction::eContextAdjustBaseRegister:
465         case EmulateInstruction::eContextRegisterPlusOffset:
466         case EmulateInstruction::eContextAdjustPC:
467         case EmulateInstruction::eContextRegisterStore:
468         case EmulateInstruction::eContextRegisterLoad:
469         case EmulateInstruction::eContextRelativeBranchImmediate:
470         case EmulateInstruction::eContextAbsoluteBranchRegister:
471         case EmulateInstruction::eContextSupervisorCall:
472         case EmulateInstruction::eContextTableBranchReadMemory:
473         case EmulateInstruction::eContextWriteRegisterRandomBits:
474         case EmulateInstruction::eContextWriteMemoryRandomBits:
475         case EmulateInstruction::eContextArithmetic:
476         case EmulateInstruction::eContextAdvancePC:
477         case EmulateInstruction::eContextReturnFromException:
478         case EmulateInstruction::eContextPopRegisterOffStack:
479         case EmulateInstruction::eContextAdjustStackPointer:
480             break;
481 
482         case EmulateInstruction::eContextPushRegisterOnStack:
483             {
484                 uint32_t reg_num = LLDB_INVALID_REGNUM;
485                 bool is_return_address_reg = false;
486                 const uint32_t unwind_reg_kind = m_unwind_plan_ptr->GetRegisterKind();
487                 if (context.info_type == EmulateInstruction::eInfoTypeRegisterToRegisterPlusOffset)
488                 {
489                     reg_num = context.info.RegisterToRegisterPlusOffset.data_reg.kinds[unwind_reg_kind];
490                     if (context.info.RegisterToRegisterPlusOffset.data_reg.kinds[eRegisterKindGeneric] == LLDB_REGNUM_GENERIC_RA)
491                         is_return_address_reg = true;
492                 }
493                 else
494                 {
495                     assert (!"unhandled case, add code to handle this!");
496                 }
497 
498                 if (reg_num != LLDB_INVALID_REGNUM)
499                 {
500                     if (m_pushed_regs.find (reg_num) == m_pushed_regs.end())
501                     {
502                         m_pushed_regs[reg_num] = addr;
503                         const int32_t offset = addr - m_initial_sp;
504                         m_curr_row->SetRegisterLocationToAtCFAPlusOffset (reg_num, offset, cant_replace);
505                         m_curr_row_modified = true;
506                         if (is_return_address_reg)
507                         {
508                             // This push was pushing the return address register,
509                             // so this is also how we will unwind the PC...
510                             RegisterInfo pc_reg_info;
511                             if (instruction->GetRegisterInfo (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC, pc_reg_info))
512                             {
513                                 uint32_t pc_reg_num = pc_reg_info.kinds[unwind_reg_kind];
514                                 if (pc_reg_num != LLDB_INVALID_REGNUM)
515                                 {
516                                     m_curr_row->SetRegisterLocationToAtCFAPlusOffset (pc_reg_num, offset, can_replace);
517                                     m_curr_row_modified = true;
518                                 }
519                             }
520                         }
521                     }
522                 }
523             }
524             break;
525 
526     }
527 
528     return dst_len;
529 }
530 
531 bool
532 UnwindAssemblyInstEmulation::ReadRegister (EmulateInstruction *instruction,
533                                            void *baton,
534                                            const RegisterInfo *reg_info,
535                                            RegisterValue &reg_value)
536 {
537 
538     if (baton && reg_info)
539         return ((UnwindAssemblyInstEmulation *)baton)->ReadRegister (instruction, reg_info, reg_value);
540     return false;
541 }
542 bool
543 UnwindAssemblyInstEmulation::ReadRegister (EmulateInstruction *instruction,
544                                            const RegisterInfo *reg_info,
545                                            RegisterValue &reg_value)
546 {
547     bool synthetic = GetRegisterValue (*reg_info, reg_value);
548 
549     LogSP log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
550 
551     if (log && log->GetVerbose ())
552     {
553 
554         StreamString strm;
555         strm.Printf ("UnwindAssemblyInstEmulation::ReadRegister  (name = \"%s\") => synthetic_value = %i, value = ", reg_info->name, synthetic);
556         reg_value.Dump(&strm, reg_info, false, false, eFormatDefault);
557         log->PutCString(strm.GetData());
558     }
559     return true;
560 }
561 
562 bool
563 UnwindAssemblyInstEmulation::WriteRegister (EmulateInstruction *instruction,
564                                             void *baton,
565                                             const EmulateInstruction::Context &context,
566                                             const RegisterInfo *reg_info,
567                                             const RegisterValue &reg_value)
568 {
569     if (baton && reg_info)
570         return ((UnwindAssemblyInstEmulation *)baton)->WriteRegister (instruction, context, reg_info, reg_value);
571     return false;
572 }
573 bool
574 UnwindAssemblyInstEmulation::WriteRegister (EmulateInstruction *instruction,
575                                             const EmulateInstruction::Context &context,
576                                             const RegisterInfo *reg_info,
577                                             const RegisterValue &reg_value)
578 {
579     LogSP log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
580 
581     if (log && log->GetVerbose ())
582     {
583 
584         StreamString strm;
585         strm.Printf ("UnwindAssemblyInstEmulation::WriteRegister (name = \"%s\", value = ", reg_info->name);
586         reg_value.Dump(&strm, reg_info, false, false, eFormatDefault);
587         strm.PutCString (", context = ");
588         context.Dump(strm, instruction);
589         log->PutCString(strm.GetData());
590     }
591 
592     const bool must_replace = true;
593     SetRegisterValue (*reg_info, reg_value);
594 
595     switch (context.type)
596     {
597         default:
598         case EmulateInstruction::eContextInvalid:
599         case EmulateInstruction::eContextReadOpcode:
600         case EmulateInstruction::eContextImmediate:
601         case EmulateInstruction::eContextAdjustBaseRegister:
602         case EmulateInstruction::eContextRegisterPlusOffset:
603         case EmulateInstruction::eContextAdjustPC:
604         case EmulateInstruction::eContextRegisterStore:
605         case EmulateInstruction::eContextRegisterLoad:
606         case EmulateInstruction::eContextAbsoluteBranchRegister:
607         case EmulateInstruction::eContextSupervisorCall:
608         case EmulateInstruction::eContextTableBranchReadMemory:
609         case EmulateInstruction::eContextWriteRegisterRandomBits:
610         case EmulateInstruction::eContextWriteMemoryRandomBits:
611         case EmulateInstruction::eContextArithmetic:
612         case EmulateInstruction::eContextAdvancePC:
613         case EmulateInstruction::eContextReturnFromException:
614         case EmulateInstruction::eContextPushRegisterOnStack:
615 //            {
616 //                const uint32_t reg_num = reg_info->kinds[m_unwind_plan_ptr->GetRegisterKind()];
617 //                if (reg_num != LLDB_INVALID_REGNUM)
618 //                {
619 //                    const bool can_replace_only_if_unspecified = true;
620 //
621 //                    m_curr_row.SetRegisterLocationToUndefined (reg_num,
622 //                                                               can_replace_only_if_unspecified,
623 //                                                               can_replace_only_if_unspecified);
624 //                    m_curr_row_modified = true;
625 //                }
626 //            }
627             break;
628 
629         case EmulateInstruction::eContextRelativeBranchImmediate:
630             {
631 
632                 {
633                     m_curr_insn_is_branch_immediate = true;
634                 }
635             }
636             break;
637 
638         case EmulateInstruction::eContextPopRegisterOffStack:
639             {
640                 const uint32_t reg_num = reg_info->kinds[m_unwind_plan_ptr->GetRegisterKind()];
641                 if (reg_num != LLDB_INVALID_REGNUM)
642                 {
643                     m_curr_row->SetRegisterLocationToSame (reg_num, must_replace);
644                     m_curr_row_modified = true;
645                     m_curr_insn_restored_a_register = true;
646                 }
647             }
648             break;
649 
650         case EmulateInstruction::eContextSetFramePointer:
651             if (!m_fp_is_cfa)
652             {
653                 m_fp_is_cfa = true;
654                 m_cfa_reg_info = *reg_info;
655                 const uint32_t cfa_reg_num = reg_info->kinds[m_unwind_plan_ptr->GetRegisterKind()];
656                 assert (cfa_reg_num != LLDB_INVALID_REGNUM);
657                 m_curr_row->SetCFARegister(cfa_reg_num);
658                 m_curr_row->SetCFAOffset(m_initial_sp - reg_value.GetAsUInt64());
659                 m_curr_row_modified = true;
660             }
661             break;
662 
663         case EmulateInstruction::eContextAdjustStackPointer:
664             // If we have created a frame using the frame pointer, don't follow
665             // subsequent adjustments to the stack pointer.
666             if (!m_fp_is_cfa)
667             {
668                 m_curr_row->SetCFAOffset (m_initial_sp - reg_value.GetAsUInt64());
669                 m_curr_row_modified = true;
670             }
671             break;
672     }
673     return true;
674 }
675 
676 
677