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 "lldb/Core/Address.h"
13 #include "lldb/Core/ArchSpec.h"
14 #include "lldb/Core/DataBufferHeap.h"
15 #include "lldb/Core/DataExtractor.h"
16 #include "lldb/Core/Disassembler.h"
17 #include "lldb/Core/Error.h"
18 #include "lldb/Core/FormatEntity.h"
19 #include "lldb/Core/Log.h"
20 #include "lldb/Core/PluginManager.h"
21 #include "lldb/Core/StreamString.h"
22 #include "lldb/Target/ExecutionContext.h"
23 #include "lldb/Target/Process.h"
24 #include "lldb/Target/Thread.h"
25 #include "lldb/Target/Target.h"
26 
27 using namespace lldb;
28 using namespace lldb_private;
29 
30 
31 
32 //-----------------------------------------------------------------------------------------------
33 //  UnwindAssemblyInstEmulation method definitions
34 //-----------------------------------------------------------------------------------------------
35 
36 bool
37 UnwindAssemblyInstEmulation::GetNonCallSiteUnwindPlanFromAssembly (AddressRange& range,
38                                                                    Thread& thread,
39                                                                    UnwindPlan& unwind_plan)
40 {
41     if (range.GetByteSize() > 0 &&
42         range.GetBaseAddress().IsValid() &&
43         m_inst_emulator_ap.get())
44     {
45 
46         // The instruction emulation subclass setup the unwind plan for the
47         // first instruction.
48         m_inst_emulator_ap->CreateFunctionEntryUnwind (unwind_plan);
49 
50         // CreateFunctionEntryUnwind should have created the first row. If it
51         // doesn't, then we are done.
52         if (unwind_plan.GetRowCount() == 0)
53             return false;
54 
55         ExecutionContext exe_ctx;
56         thread.CalculateExecutionContext(exe_ctx);
57         const bool prefer_file_cache = true;
58         DisassemblerSP disasm_sp (Disassembler::DisassembleRange (m_arch,
59                                                                   NULL,
60                                                                   NULL,
61                                                                   exe_ctx,
62                                                                   range,
63                                                                   prefer_file_cache));
64 
65         Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
66 
67         if (disasm_sp)
68         {
69 
70             m_range_ptr = ⦥
71             m_thread_ptr = &thread;
72             m_unwind_plan_ptr = &unwind_plan;
73 
74             const uint32_t addr_byte_size = m_arch.GetAddressByteSize();
75             const bool show_address = true;
76             const bool show_bytes = true;
77             m_inst_emulator_ap->GetRegisterInfo (unwind_plan.GetRegisterKind(),
78                                                  unwind_plan.GetInitialCFARegister(),
79                                                  m_cfa_reg_info);
80 
81             m_fp_is_cfa = false;
82             m_register_values.clear();
83             m_pushed_regs.clear();
84 
85             // Initialize the CFA with a known value. In the 32 bit case
86             // it will be 0x80000000, and in the 64 bit case 0x8000000000000000.
87             // We use the address byte size to be safe for any future address sizes
88             m_initial_sp = (1ull << ((addr_byte_size * 8) - 1));
89             RegisterValue cfa_reg_value;
90             cfa_reg_value.SetUInt (m_initial_sp, m_cfa_reg_info.byte_size);
91             SetRegisterValue (m_cfa_reg_info, cfa_reg_value);
92 
93             const InstructionList &inst_list = disasm_sp->GetInstructionList ();
94             const size_t num_instructions = inst_list.GetSize();
95 
96             if (num_instructions > 0)
97             {
98                 Instruction *inst = inst_list.GetInstructionAtIndex (0).get();
99                 const lldb::addr_t base_addr = inst->GetAddress().GetFileAddress();
100 
101                 // Map for storing the unwind plan row and the value of the registers at a given offset.
102                 // When we see a forward branch we add a new entry to this map with the actual unwind plan
103                 // row and register context for the target address of the branch as the current data have
104                 // to be valid for the target address of the branch too if we are in the same function.
105                 std::map<lldb::addr_t, std::pair<UnwindPlan::RowSP, RegisterValueMap>> saved_unwind_states;
106 
107                 // Make a copy of the current instruction Row and save it in m_curr_row
108                 // so we can add updates as we process the instructions.
109                 UnwindPlan::RowSP last_row = unwind_plan.GetLastRow();
110                 UnwindPlan::Row *newrow = new UnwindPlan::Row;
111                 if (last_row.get())
112                     *newrow = *last_row.get();
113                 m_curr_row.reset(newrow);
114 
115                 // Add the initial state to the save list with offset 0.
116                 saved_unwind_states.insert({0, {last_row, m_register_values}});
117 
118                 // cache the pc register number (in whatever register numbering this UnwindPlan uses) for
119                 // quick reference during instruction parsing.
120                 uint32_t pc_reg_num = LLDB_INVALID_REGNUM;
121                 RegisterInfo pc_reg_info;
122                 if (m_inst_emulator_ap->GetRegisterInfo (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC, pc_reg_info))
123                     pc_reg_num = pc_reg_info.kinds[unwind_plan.GetRegisterKind()];
124                 else
125                     pc_reg_num = LLDB_INVALID_REGNUM;
126 
127                 // cache the return address register number (in whatever register numbering this UnwindPlan uses) for
128                 // quick reference during instruction parsing.
129                 uint32_t ra_reg_num = LLDB_INVALID_REGNUM;
130                 RegisterInfo ra_reg_info;
131                 if (m_inst_emulator_ap->GetRegisterInfo (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_RA, ra_reg_info))
132                     ra_reg_num = ra_reg_info.kinds[unwind_plan.GetRegisterKind()];
133                 else
134                     ra_reg_num = LLDB_INVALID_REGNUM;
135 
136                 for (size_t idx=0; idx<num_instructions; ++idx)
137                 {
138                     m_curr_row_modified = false;
139                     m_forward_branch_offset = 0;
140 
141                     inst = inst_list.GetInstructionAtIndex (idx).get();
142                     if (inst)
143                     {
144                         lldb::addr_t current_offset = inst->GetAddress().GetFileAddress() - base_addr;
145                         auto it = saved_unwind_states.upper_bound(current_offset);
146                         assert(it != saved_unwind_states.begin() && "Unwind row for the function entry missing");
147                         --it; // Move it to the row corresponding to the current offset
148 
149                         // If the offset of m_curr_row don't match with the offset we see in saved_unwind_states
150                         // then we have to update m_curr_row and m_register_values based on the saved values. It
151                         // is happenning after we processed an epilogue and a return to caller instruction.
152                         if (it->second.first->GetOffset() != m_curr_row->GetOffset())
153                         {
154                             UnwindPlan::Row *newrow = new UnwindPlan::Row;
155                             *newrow = *it->second.first;
156                             m_curr_row.reset(newrow);
157                             m_register_values = it->second.second;;
158                         }
159 
160                         if (log && log->GetVerbose ())
161                         {
162                             StreamString strm;
163                             lldb_private::FormatEntity::Entry format;
164                             FormatEntity::Parse("${frame.pc}: ", format);
165                             inst->Dump(&strm, inst_list.GetMaxOpcocdeByteSize (), show_address, show_bytes, NULL, NULL, NULL, &format, 0);
166                             log->PutCString (strm.GetData());
167                         }
168 
169                         m_inst_emulator_ap->SetInstruction (inst->GetOpcode(),
170                                                             inst->GetAddress(),
171                                                             exe_ctx.GetTargetPtr());
172 
173                         m_inst_emulator_ap->EvaluateInstruction (eEmulateInstructionOptionIgnoreConditions);
174 
175                         // If the current instruction is a branch forward then save the current CFI information
176                         // for the offset where we are branching.
177                         if (m_forward_branch_offset != 0 && range.ContainsFileAddress(inst->GetAddress().GetFileAddress() + m_forward_branch_offset))
178                         {
179                             auto newrow = std::make_shared<UnwindPlan::Row>(*m_curr_row.get());
180                             newrow->SetOffset(current_offset + m_forward_branch_offset);
181                             saved_unwind_states.insert({current_offset + m_forward_branch_offset, {newrow, m_register_values}});
182                             unwind_plan.InsertRow(newrow);
183                         }
184 
185                         // Were there any changes to the CFI while evaluating this instruction?
186                         if (m_curr_row_modified)
187                         {
188                             // Save the modified row if we don't already have a CFI row in the currennt address
189                             if (saved_unwind_states.count(current_offset + inst->GetOpcode().GetByteSize()) == 0)
190                             {
191                                 m_curr_row->SetOffset (current_offset + inst->GetOpcode().GetByteSize());
192                                 unwind_plan.InsertRow (m_curr_row);
193                                 saved_unwind_states.insert({current_offset + inst->GetOpcode().GetByteSize(), {m_curr_row, m_register_values}});
194 
195                                 // Allocate a new Row for m_curr_row, copy the current state into it
196                                 UnwindPlan::Row *newrow = new UnwindPlan::Row;
197                                 *newrow = *m_curr_row.get();
198                                 m_curr_row.reset(newrow);
199                             }
200                         }
201                     }
202                 }
203             }
204             // FIXME: The DisassemblerLLVMC has a reference cycle and won't go away if it has any active instructions.
205             // I'll fix that but for now, just clear the list and it will go away nicely.
206             disasm_sp->GetInstructionList().Clear();
207         }
208 
209         if (log && log->GetVerbose ())
210         {
211             StreamString strm;
212             lldb::addr_t base_addr = range.GetBaseAddress().GetLoadAddress(thread.CalculateTarget().get());
213             strm.Printf ("Resulting unwind rows for [0x%" PRIx64 " - 0x%" PRIx64 "):", base_addr, base_addr + range.GetByteSize());
214             unwind_plan.Dump(strm, &thread, base_addr);
215             log->PutCString (strm.GetData());
216         }
217         return unwind_plan.GetRowCount() > 0;
218     }
219     return false;
220 }
221 
222 bool
223 UnwindAssemblyInstEmulation::AugmentUnwindPlanFromCallSite (AddressRange& func,
224                                                             Thread& thread,
225                                                             UnwindPlan& unwind_plan)
226 {
227     return false;
228 }
229 
230 bool
231 UnwindAssemblyInstEmulation::GetFastUnwindPlan (AddressRange& func,
232                                                 Thread& thread,
233                                                 UnwindPlan &unwind_plan)
234 {
235     return false;
236 }
237 
238 bool
239 UnwindAssemblyInstEmulation::FirstNonPrologueInsn (AddressRange& func,
240                                                    const ExecutionContext &exe_ctx,
241                                                    Address& first_non_prologue_insn)
242 {
243     return false;
244 }
245 
246 UnwindAssembly *
247 UnwindAssemblyInstEmulation::CreateInstance (const ArchSpec &arch)
248 {
249     std::unique_ptr<EmulateInstruction> inst_emulator_ap (EmulateInstruction::FindPlugin (arch, eInstructionTypePrologueEpilogue, NULL));
250     // Make sure that all prologue instructions are handled
251     if (inst_emulator_ap.get())
252         return new UnwindAssemblyInstEmulation (arch, inst_emulator_ap.release());
253     return NULL;
254 }
255 
256 
257 //------------------------------------------------------------------
258 // PluginInterface protocol in UnwindAssemblyParser_x86
259 //------------------------------------------------------------------
260 ConstString
261 UnwindAssemblyInstEmulation::GetPluginName()
262 {
263     return GetPluginNameStatic();
264 }
265 
266 uint32_t
267 UnwindAssemblyInstEmulation::GetPluginVersion()
268 {
269     return 1;
270 }
271 
272 void
273 UnwindAssemblyInstEmulation::Initialize()
274 {
275     PluginManager::RegisterPlugin (GetPluginNameStatic(),
276                                    GetPluginDescriptionStatic(),
277                                    CreateInstance);
278 }
279 
280 void
281 UnwindAssemblyInstEmulation::Terminate()
282 {
283     PluginManager::UnregisterPlugin (CreateInstance);
284 }
285 
286 
287 ConstString
288 UnwindAssemblyInstEmulation::GetPluginNameStatic()
289 {
290     static ConstString g_name("inst-emulation");
291     return g_name;
292 }
293 
294 const char *
295 UnwindAssemblyInstEmulation::GetPluginDescriptionStatic()
296 {
297     return "Instruction emulation based unwind information.";
298 }
299 
300 
301 uint64_t
302 UnwindAssemblyInstEmulation::MakeRegisterKindValuePair (const RegisterInfo &reg_info)
303 {
304     lldb::RegisterKind reg_kind;
305     uint32_t reg_num;
306     if (EmulateInstruction::GetBestRegisterKindAndNumber (&reg_info, reg_kind, reg_num))
307         return (uint64_t)reg_kind << 24 | reg_num;
308     return 0ull;
309 }
310 
311 void
312 UnwindAssemblyInstEmulation::SetRegisterValue (const RegisterInfo &reg_info, const RegisterValue &reg_value)
313 {
314     m_register_values[MakeRegisterKindValuePair (reg_info)] = reg_value;
315 }
316 
317 bool
318 UnwindAssemblyInstEmulation::GetRegisterValue (const RegisterInfo &reg_info, RegisterValue &reg_value)
319 {
320     const uint64_t reg_id = MakeRegisterKindValuePair (reg_info);
321     RegisterValueMap::const_iterator pos = m_register_values.find(reg_id);
322     if (pos != m_register_values.end())
323     {
324         reg_value = pos->second;
325         return true; // We had a real value that comes from an opcode that wrote
326                      // to it...
327     }
328     // We are making up a value that is recognizable...
329     reg_value.SetUInt(reg_id, reg_info.byte_size);
330     return false;
331 }
332 
333 
334 size_t
335 UnwindAssemblyInstEmulation::ReadMemory (EmulateInstruction *instruction,
336                                          void *baton,
337                                          const EmulateInstruction::Context &context,
338                                          lldb::addr_t addr,
339                                          void *dst,
340                                          size_t dst_len)
341 {
342     Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
343 
344     if (log && log->GetVerbose ())
345     {
346         StreamString strm;
347         strm.Printf ("UnwindAssemblyInstEmulation::ReadMemory    (addr = 0x%16.16" PRIx64 ", dst = %p, dst_len = %" PRIu64 ", context = ",
348                      addr,
349                      dst,
350                      (uint64_t)dst_len);
351         context.Dump(strm, instruction);
352         log->PutCString (strm.GetData ());
353     }
354     memset (dst, 0, dst_len);
355     return dst_len;
356 }
357 
358 size_t
359 UnwindAssemblyInstEmulation::WriteMemory (EmulateInstruction *instruction,
360                                           void *baton,
361                                           const EmulateInstruction::Context &context,
362                                           lldb::addr_t addr,
363                                           const void *dst,
364                                           size_t dst_len)
365 {
366     if (baton && dst && dst_len)
367         return ((UnwindAssemblyInstEmulation *)baton)->WriteMemory (instruction, context, addr, dst, dst_len);
368     return 0;
369 }
370 
371 size_t
372 UnwindAssemblyInstEmulation::WriteMemory (EmulateInstruction *instruction,
373                                           const EmulateInstruction::Context &context,
374                                           lldb::addr_t addr,
375                                           const void *dst,
376                                           size_t dst_len)
377 {
378     DataExtractor data (dst,
379                         dst_len,
380                         instruction->GetArchitecture ().GetByteOrder(),
381                         instruction->GetArchitecture ().GetAddressByteSize());
382 
383     Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
384 
385     if (log && log->GetVerbose ())
386     {
387         StreamString strm;
388 
389         strm.PutCString ("UnwindAssemblyInstEmulation::WriteMemory   (");
390         data.Dump(&strm, 0, eFormatBytes, 1, dst_len, UINT32_MAX, addr, 0, 0);
391         strm.PutCString (", context = ");
392         context.Dump(strm, instruction);
393         log->PutCString (strm.GetData());
394     }
395 
396     const bool cant_replace = false;
397 
398     switch (context.type)
399     {
400         default:
401         case EmulateInstruction::eContextInvalid:
402         case EmulateInstruction::eContextReadOpcode:
403         case EmulateInstruction::eContextImmediate:
404         case EmulateInstruction::eContextAdjustBaseRegister:
405         case EmulateInstruction::eContextRegisterPlusOffset:
406         case EmulateInstruction::eContextAdjustPC:
407         case EmulateInstruction::eContextRegisterStore:
408         case EmulateInstruction::eContextRegisterLoad:
409         case EmulateInstruction::eContextRelativeBranchImmediate:
410         case EmulateInstruction::eContextAbsoluteBranchRegister:
411         case EmulateInstruction::eContextSupervisorCall:
412         case EmulateInstruction::eContextTableBranchReadMemory:
413         case EmulateInstruction::eContextWriteRegisterRandomBits:
414         case EmulateInstruction::eContextWriteMemoryRandomBits:
415         case EmulateInstruction::eContextArithmetic:
416         case EmulateInstruction::eContextAdvancePC:
417         case EmulateInstruction::eContextReturnFromException:
418         case EmulateInstruction::eContextPopRegisterOffStack:
419         case EmulateInstruction::eContextAdjustStackPointer:
420             break;
421 
422         case EmulateInstruction::eContextPushRegisterOnStack:
423             {
424                 uint32_t reg_num = LLDB_INVALID_REGNUM;
425                 uint32_t generic_regnum = LLDB_INVALID_REGNUM;
426                 if (context.info_type == EmulateInstruction::eInfoTypeRegisterToRegisterPlusOffset)
427                 {
428                     const uint32_t unwind_reg_kind = m_unwind_plan_ptr->GetRegisterKind();
429                     reg_num = context.info.RegisterToRegisterPlusOffset.data_reg.kinds[unwind_reg_kind];
430                     generic_regnum = context.info.RegisterToRegisterPlusOffset.data_reg.kinds[eRegisterKindGeneric];
431                 }
432                 else
433                     assert (!"unhandled case, add code to handle this!");
434 
435                 if (reg_num != LLDB_INVALID_REGNUM && generic_regnum != LLDB_REGNUM_GENERIC_SP)
436                 {
437                     if (m_pushed_regs.find (reg_num) == m_pushed_regs.end())
438                     {
439                         m_pushed_regs[reg_num] = addr;
440                         const int32_t offset = addr - m_initial_sp;
441                         m_curr_row->SetRegisterLocationToAtCFAPlusOffset (reg_num, offset, cant_replace);
442                         m_curr_row_modified = true;
443                     }
444                 }
445             }
446             break;
447 
448     }
449 
450     return dst_len;
451 }
452 
453 bool
454 UnwindAssemblyInstEmulation::ReadRegister (EmulateInstruction *instruction,
455                                            void *baton,
456                                            const RegisterInfo *reg_info,
457                                            RegisterValue &reg_value)
458 {
459 
460     if (baton && reg_info)
461         return ((UnwindAssemblyInstEmulation *)baton)->ReadRegister (instruction, reg_info, reg_value);
462     return false;
463 }
464 bool
465 UnwindAssemblyInstEmulation::ReadRegister (EmulateInstruction *instruction,
466                                            const RegisterInfo *reg_info,
467                                            RegisterValue &reg_value)
468 {
469     bool synthetic = GetRegisterValue (*reg_info, reg_value);
470 
471     Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
472 
473     if (log && log->GetVerbose ())
474     {
475 
476         StreamString strm;
477         strm.Printf ("UnwindAssemblyInstEmulation::ReadRegister  (name = \"%s\") => synthetic_value = %i, value = ", reg_info->name, synthetic);
478         reg_value.Dump(&strm, reg_info, false, false, eFormatDefault);
479         log->PutCString(strm.GetData());
480     }
481     return true;
482 }
483 
484 bool
485 UnwindAssemblyInstEmulation::WriteRegister (EmulateInstruction *instruction,
486                                             void *baton,
487                                             const EmulateInstruction::Context &context,
488                                             const RegisterInfo *reg_info,
489                                             const RegisterValue &reg_value)
490 {
491     if (baton && reg_info)
492         return ((UnwindAssemblyInstEmulation *)baton)->WriteRegister (instruction, context, reg_info, reg_value);
493     return false;
494 }
495 bool
496 UnwindAssemblyInstEmulation::WriteRegister (EmulateInstruction *instruction,
497                                             const EmulateInstruction::Context &context,
498                                             const RegisterInfo *reg_info,
499                                             const RegisterValue &reg_value)
500 {
501     Log *log(GetLogIfAllCategoriesSet (LIBLLDB_LOG_UNWIND));
502 
503     if (log && log->GetVerbose ())
504     {
505 
506         StreamString strm;
507         strm.Printf ("UnwindAssemblyInstEmulation::WriteRegister (name = \"%s\", value = ", reg_info->name);
508         reg_value.Dump(&strm, reg_info, false, false, eFormatDefault);
509         strm.PutCString (", context = ");
510         context.Dump(strm, instruction);
511         log->PutCString(strm.GetData());
512     }
513 
514     if (!instruction->IsInstructionConditional())
515         SetRegisterValue (*reg_info, reg_value);
516 
517     switch (context.type)
518     {
519         case EmulateInstruction::eContextInvalid:
520         case EmulateInstruction::eContextReadOpcode:
521         case EmulateInstruction::eContextImmediate:
522         case EmulateInstruction::eContextAdjustBaseRegister:
523         case EmulateInstruction::eContextRegisterPlusOffset:
524         case EmulateInstruction::eContextAdjustPC:
525         case EmulateInstruction::eContextRegisterStore:
526         case EmulateInstruction::eContextSupervisorCall:
527         case EmulateInstruction::eContextTableBranchReadMemory:
528         case EmulateInstruction::eContextWriteRegisterRandomBits:
529         case EmulateInstruction::eContextWriteMemoryRandomBits:
530         case EmulateInstruction::eContextArithmetic:
531         case EmulateInstruction::eContextAdvancePC:
532         case EmulateInstruction::eContextReturnFromException:
533         case EmulateInstruction::eContextPushRegisterOnStack:
534         case EmulateInstruction::eContextRegisterLoad:
535 //            {
536 //                const uint32_t reg_num = reg_info->kinds[m_unwind_plan_ptr->GetRegisterKind()];
537 //                if (reg_num != LLDB_INVALID_REGNUM)
538 //                {
539 //                    const bool can_replace_only_if_unspecified = true;
540 //
541 //                    m_curr_row.SetRegisterLocationToUndefined (reg_num,
542 //                                                               can_replace_only_if_unspecified,
543 //                                                               can_replace_only_if_unspecified);
544 //                    m_curr_row_modified = true;
545 //                }
546 //            }
547             break;
548 
549         case EmulateInstruction::eContextAbsoluteBranchRegister:
550         case EmulateInstruction::eContextRelativeBranchImmediate:
551             {
552                 if (context.info_type == EmulateInstruction::eInfoTypeISAAndImmediate &&
553                     context.info.ISAAndImmediate.unsigned_data32 > 0)
554                 {
555                     m_forward_branch_offset = context.info.ISAAndImmediateSigned.signed_data32;
556                 }
557                 else if (context.info_type == EmulateInstruction::eInfoTypeISAAndImmediateSigned &&
558                          context.info.ISAAndImmediateSigned.signed_data32 > 0)
559                 {
560                     m_forward_branch_offset = context.info.ISAAndImmediate.unsigned_data32;
561                 }
562                 else if (context.info_type == EmulateInstruction::eInfoTypeImmediate &&
563                          context.info.unsigned_immediate > 0)
564                 {
565                     m_forward_branch_offset = context.info.unsigned_immediate;
566                 }
567                 else if (context.info_type == EmulateInstruction::eInfoTypeImmediateSigned &&
568                          context.info.signed_immediate > 0)
569                 {
570                     m_forward_branch_offset = context.info.signed_immediate;
571                 }
572             }
573             break;
574 
575         case EmulateInstruction::eContextPopRegisterOffStack:
576             {
577                 if (!instruction->IsInstructionConditional())
578                 {
579                     const uint32_t reg_num = reg_info->kinds[m_unwind_plan_ptr->GetRegisterKind()];
580                     const uint32_t generic_regnum = reg_info->kinds[eRegisterKindGeneric];
581                     if (reg_num != LLDB_INVALID_REGNUM && generic_regnum != LLDB_REGNUM_GENERIC_SP)
582                     {
583                         switch (context.info_type)
584                         {
585                             case EmulateInstruction::eInfoTypeAddress:
586                                 if (m_pushed_regs.find(reg_num) != m_pushed_regs.end() &&
587                                     context.info.address == m_pushed_regs[reg_num])
588                                 {
589                                     m_curr_row->SetRegisterLocationToSame(reg_num,
590                                                                           false /*must_replace*/);
591                                     m_curr_row_modified = true;
592                                 }
593                                 break;
594                             case EmulateInstruction::eInfoTypeISA:
595                                 assert((generic_regnum == LLDB_REGNUM_GENERIC_PC ||
596                                         generic_regnum == LLDB_REGNUM_GENERIC_FLAGS) &&
597                                        "eInfoTypeISA used for poping a register other the the PC/FLAGS");
598                                 if (generic_regnum != LLDB_REGNUM_GENERIC_FLAGS)
599                                 {
600                                     m_curr_row->SetRegisterLocationToSame(reg_num,
601                                                                           false /*must_replace*/);
602                                     m_curr_row_modified = true;
603                                 }
604                                 break;
605                             default:
606                                 assert(false && "unhandled case, add code to handle this!");
607                                 break;
608                         }
609                     }
610                 }
611             }
612             break;
613 
614         case EmulateInstruction::eContextSetFramePointer:
615             if (!m_fp_is_cfa && !instruction->IsInstructionConditional())
616             {
617                 m_fp_is_cfa = true;
618                 m_cfa_reg_info = *reg_info;
619                 const uint32_t cfa_reg_num = reg_info->kinds[m_unwind_plan_ptr->GetRegisterKind()];
620                 assert (cfa_reg_num != LLDB_INVALID_REGNUM);
621                 m_curr_row->GetCFAValue().SetIsRegisterPlusOffset(cfa_reg_num, m_initial_sp -
622                         reg_value.GetAsUInt64());
623                 m_curr_row_modified = true;
624             }
625             break;
626 
627         case EmulateInstruction::eContextAdjustStackPointer:
628             // If we have created a frame using the frame pointer, don't follow
629             // subsequent adjustments to the stack pointer.
630             if (!m_fp_is_cfa && !instruction->IsInstructionConditional())
631             {
632                 m_curr_row->GetCFAValue().SetIsRegisterPlusOffset(
633                         m_curr_row->GetCFAValue().GetRegisterNumber(),
634                         m_initial_sp - reg_value.GetAsUInt64());
635                 m_curr_row_modified = true;
636             }
637             break;
638     }
639     return true;
640 }
641 
642 
643