1 //===-- StackFrame.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 // C Includes
11 // C++ Includes
12 // Other libraries and framework includes
13 // Project includes
14 #include "lldb/Target/StackFrame.h"
15 #include "lldb/Core/Debugger.h"
16 #include "lldb/Core/Disassembler.h"
17 #include "lldb/Core/FormatEntity.h"
18 #include "lldb/Core/Mangled.h"
19 #include "lldb/Core/Module.h"
20 #include "lldb/Core/Value.h"
21 #include "lldb/Core/ValueObjectConstResult.h"
22 #include "lldb/Core/ValueObjectMemory.h"
23 #include "lldb/Core/ValueObjectVariable.h"
24 #include "lldb/Symbol/CompileUnit.h"
25 #include "lldb/Symbol/Function.h"
26 #include "lldb/Symbol/Symbol.h"
27 #include "lldb/Symbol/SymbolContextScope.h"
28 #include "lldb/Symbol/Type.h"
29 #include "lldb/Symbol/VariableList.h"
30 #include "lldb/Target/ABI.h"
31 #include "lldb/Target/ExecutionContext.h"
32 #include "lldb/Target/Process.h"
33 #include "lldb/Target/RegisterContext.h"
34 #include "lldb/Target/Target.h"
35 #include "lldb/Target/Thread.h"
36 
37 using namespace lldb;
38 using namespace lldb_private;
39 
40 // The first bits in the flags are reserved for the SymbolContext::Scope bits
41 // so we know if we have tried to look up information in our internal symbol
42 // context (m_sc) already.
43 #define RESOLVED_FRAME_CODE_ADDR (uint32_t(eSymbolContextEverything + 1))
44 #define RESOLVED_FRAME_ID_SYMBOL_SCOPE (RESOLVED_FRAME_CODE_ADDR << 1)
45 #define GOT_FRAME_BASE (RESOLVED_FRAME_ID_SYMBOL_SCOPE << 1)
46 #define RESOLVED_VARIABLES (GOT_FRAME_BASE << 1)
47 #define RESOLVED_GLOBAL_VARIABLES (RESOLVED_VARIABLES << 1)
48 
49 StackFrame::StackFrame(const ThreadSP &thread_sp, user_id_t frame_idx,
50                        user_id_t unwind_frame_index, addr_t cfa,
51                        bool cfa_is_valid, addr_t pc, uint32_t stop_id,
52                        bool stop_id_is_valid, bool is_history_frame,
53                        const SymbolContext *sc_ptr)
54     : m_thread_wp(thread_sp), m_frame_index(frame_idx),
55       m_concrete_frame_index(unwind_frame_index), m_reg_context_sp(),
56       m_id(pc, cfa, nullptr), m_frame_code_addr(pc), m_sc(), m_flags(),
57       m_frame_base(), m_frame_base_error(), m_cfa_is_valid(cfa_is_valid),
58       m_stop_id(stop_id), m_stop_id_is_valid(stop_id_is_valid),
59       m_is_history_frame(is_history_frame), m_variable_list_sp(),
60       m_variable_list_value_objects(), m_disassembly(), m_mutex() {
61   // If we don't have a CFA value, use the frame index for our StackID so that
62   // recursive
63   // functions properly aren't confused with one another on a history stack.
64   if (m_is_history_frame && !m_cfa_is_valid) {
65     m_id.SetCFA(m_frame_index);
66   }
67 
68   if (sc_ptr != nullptr) {
69     m_sc = *sc_ptr;
70     m_flags.Set(m_sc.GetResolvedMask());
71   }
72 }
73 
74 StackFrame::StackFrame(const ThreadSP &thread_sp, user_id_t frame_idx,
75                        user_id_t unwind_frame_index,
76                        const RegisterContextSP &reg_context_sp, addr_t cfa,
77                        addr_t pc, const SymbolContext *sc_ptr)
78     : m_thread_wp(thread_sp), m_frame_index(frame_idx),
79       m_concrete_frame_index(unwind_frame_index),
80       m_reg_context_sp(reg_context_sp), m_id(pc, cfa, nullptr),
81       m_frame_code_addr(pc), m_sc(), m_flags(), m_frame_base(),
82       m_frame_base_error(), m_cfa_is_valid(true), m_stop_id(0),
83       m_stop_id_is_valid(false), m_is_history_frame(false),
84       m_variable_list_sp(), m_variable_list_value_objects(), m_disassembly(),
85       m_mutex() {
86   if (sc_ptr != nullptr) {
87     m_sc = *sc_ptr;
88     m_flags.Set(m_sc.GetResolvedMask());
89   }
90 
91   if (reg_context_sp && !m_sc.target_sp) {
92     m_sc.target_sp = reg_context_sp->CalculateTarget();
93     if (m_sc.target_sp)
94       m_flags.Set(eSymbolContextTarget);
95   }
96 }
97 
98 StackFrame::StackFrame(const ThreadSP &thread_sp, user_id_t frame_idx,
99                        user_id_t unwind_frame_index,
100                        const RegisterContextSP &reg_context_sp, addr_t cfa,
101                        const Address &pc_addr, const SymbolContext *sc_ptr)
102     : m_thread_wp(thread_sp), m_frame_index(frame_idx),
103       m_concrete_frame_index(unwind_frame_index),
104       m_reg_context_sp(reg_context_sp),
105       m_id(pc_addr.GetLoadAddress(thread_sp->CalculateTarget().get()), cfa,
106            nullptr),
107       m_frame_code_addr(pc_addr), m_sc(), m_flags(), m_frame_base(),
108       m_frame_base_error(), m_cfa_is_valid(true), m_stop_id(0),
109       m_stop_id_is_valid(false), m_is_history_frame(false),
110       m_variable_list_sp(), m_variable_list_value_objects(), m_disassembly(),
111       m_mutex() {
112   if (sc_ptr != nullptr) {
113     m_sc = *sc_ptr;
114     m_flags.Set(m_sc.GetResolvedMask());
115   }
116 
117   if (!m_sc.target_sp && reg_context_sp) {
118     m_sc.target_sp = reg_context_sp->CalculateTarget();
119     if (m_sc.target_sp)
120       m_flags.Set(eSymbolContextTarget);
121   }
122 
123   ModuleSP pc_module_sp(pc_addr.GetModule());
124   if (!m_sc.module_sp || m_sc.module_sp != pc_module_sp) {
125     if (pc_module_sp) {
126       m_sc.module_sp = pc_module_sp;
127       m_flags.Set(eSymbolContextModule);
128     } else {
129       m_sc.module_sp.reset();
130     }
131   }
132 }
133 
134 StackFrame::~StackFrame() = default;
135 
136 StackID &StackFrame::GetStackID() {
137   std::lock_guard<std::recursive_mutex> guard(m_mutex);
138   // Make sure we have resolved the StackID object's symbol context scope if
139   // we already haven't looked it up.
140 
141   if (m_flags.IsClear(RESOLVED_FRAME_ID_SYMBOL_SCOPE)) {
142     if (m_id.GetSymbolContextScope()) {
143       // We already have a symbol context scope, we just don't have our
144       // flag bit set.
145       m_flags.Set(RESOLVED_FRAME_ID_SYMBOL_SCOPE);
146     } else {
147       // Calculate the frame block and use this for the stack ID symbol
148       // context scope if we have one.
149       SymbolContextScope *scope = GetFrameBlock();
150       if (scope == nullptr) {
151         // We don't have a block, so use the symbol
152         if (m_flags.IsClear(eSymbolContextSymbol))
153           GetSymbolContext(eSymbolContextSymbol);
154 
155         // It is ok if m_sc.symbol is nullptr here
156         scope = m_sc.symbol;
157       }
158       // Set the symbol context scope (the accessor will set the
159       // RESOLVED_FRAME_ID_SYMBOL_SCOPE bit in m_flags).
160       SetSymbolContextScope(scope);
161     }
162   }
163   return m_id;
164 }
165 
166 uint32_t StackFrame::GetFrameIndex() const {
167   ThreadSP thread_sp = GetThread();
168   if (thread_sp)
169     return thread_sp->GetStackFrameList()->GetVisibleStackFrameIndex(
170         m_frame_index);
171   else
172     return m_frame_index;
173 }
174 
175 void StackFrame::SetSymbolContextScope(SymbolContextScope *symbol_scope) {
176   std::lock_guard<std::recursive_mutex> guard(m_mutex);
177   m_flags.Set(RESOLVED_FRAME_ID_SYMBOL_SCOPE);
178   m_id.SetSymbolContextScope(symbol_scope);
179 }
180 
181 const Address &StackFrame::GetFrameCodeAddress() {
182   std::lock_guard<std::recursive_mutex> guard(m_mutex);
183   if (m_flags.IsClear(RESOLVED_FRAME_CODE_ADDR) &&
184       !m_frame_code_addr.IsSectionOffset()) {
185     m_flags.Set(RESOLVED_FRAME_CODE_ADDR);
186 
187     // Resolve the PC into a temporary address because if ResolveLoadAddress
188     // fails to resolve the address, it will clear the address object...
189     ThreadSP thread_sp(GetThread());
190     if (thread_sp) {
191       TargetSP target_sp(thread_sp->CalculateTarget());
192       if (target_sp) {
193         if (m_frame_code_addr.SetOpcodeLoadAddress(
194                 m_frame_code_addr.GetOffset(), target_sp.get(),
195                 eAddressClassCode)) {
196           ModuleSP module_sp(m_frame_code_addr.GetModule());
197           if (module_sp) {
198             m_sc.module_sp = module_sp;
199             m_flags.Set(eSymbolContextModule);
200           }
201         }
202       }
203     }
204   }
205   return m_frame_code_addr;
206 }
207 
208 bool StackFrame::ChangePC(addr_t pc) {
209   std::lock_guard<std::recursive_mutex> guard(m_mutex);
210   // We can't change the pc value of a history stack frame - it is immutable.
211   if (m_is_history_frame)
212     return false;
213   m_frame_code_addr.SetRawAddress(pc);
214   m_sc.Clear(false);
215   m_flags.Reset(0);
216   ThreadSP thread_sp(GetThread());
217   if (thread_sp)
218     thread_sp->ClearStackFrames();
219   return true;
220 }
221 
222 const char *StackFrame::Disassemble() {
223   std::lock_guard<std::recursive_mutex> guard(m_mutex);
224   if (m_disassembly.GetSize() == 0) {
225     ExecutionContext exe_ctx(shared_from_this());
226     Target *target = exe_ctx.GetTargetPtr();
227     if (target) {
228       const char *plugin_name = nullptr;
229       const char *flavor = nullptr;
230       Disassembler::Disassemble(target->GetDebugger(),
231                                 target->GetArchitecture(), plugin_name, flavor,
232                                 exe_ctx, 0, 0, 0, m_disassembly);
233     }
234     if (m_disassembly.GetSize() == 0)
235       return nullptr;
236   }
237   return m_disassembly.GetData();
238 }
239 
240 Block *StackFrame::GetFrameBlock() {
241   if (m_sc.block == nullptr && m_flags.IsClear(eSymbolContextBlock))
242     GetSymbolContext(eSymbolContextBlock);
243 
244   if (m_sc.block) {
245     Block *inline_block = m_sc.block->GetContainingInlinedBlock();
246     if (inline_block) {
247       // Use the block with the inlined function info
248       // as the frame block we want this frame to have only the variables
249       // for the inlined function and its non-inlined block child blocks.
250       return inline_block;
251     } else {
252       // This block is not contained within any inlined function blocks
253       // with so we want to use the top most function block.
254       return &m_sc.function->GetBlock(false);
255     }
256   }
257   return nullptr;
258 }
259 
260 //----------------------------------------------------------------------
261 // Get the symbol context if we already haven't done so by resolving the
262 // PC address as much as possible. This way when we pass around a
263 // StackFrame object, everyone will have as much information as
264 // possible and no one will ever have to look things up manually.
265 //----------------------------------------------------------------------
266 const SymbolContext &StackFrame::GetSymbolContext(uint32_t resolve_scope) {
267   std::lock_guard<std::recursive_mutex> guard(m_mutex);
268   // Copy our internal symbol context into "sc".
269   if ((m_flags.Get() & resolve_scope) != resolve_scope) {
270     uint32_t resolved = 0;
271 
272     // If the target was requested add that:
273     if (!m_sc.target_sp) {
274       m_sc.target_sp = CalculateTarget();
275       if (m_sc.target_sp)
276         resolved |= eSymbolContextTarget;
277     }
278 
279     // Resolve our PC to section offset if we haven't already done so
280     // and if we don't have a module. The resolved address section will
281     // contain the module to which it belongs
282     if (!m_sc.module_sp && m_flags.IsClear(RESOLVED_FRAME_CODE_ADDR))
283       GetFrameCodeAddress();
284 
285     // If this is not frame zero, then we need to subtract 1 from the PC
286     // value when doing address lookups since the PC will be on the
287     // instruction following the function call instruction...
288 
289     Address lookup_addr(GetFrameCodeAddress());
290     if (m_frame_index > 0 && lookup_addr.IsValid()) {
291       addr_t offset = lookup_addr.GetOffset();
292       if (offset > 0) {
293         lookup_addr.SetOffset(offset - 1);
294 
295       } else {
296         // lookup_addr is the start of a section.  We need
297         // do the math on the actual load address and re-compute
298         // the section.  We're working with a 'noreturn' function
299         // at the end of a section.
300         ThreadSP thread_sp(GetThread());
301         if (thread_sp) {
302           TargetSP target_sp(thread_sp->CalculateTarget());
303           if (target_sp) {
304             addr_t addr_minus_one =
305                 lookup_addr.GetLoadAddress(target_sp.get()) - 1;
306             lookup_addr.SetLoadAddress(addr_minus_one, target_sp.get());
307           } else {
308             lookup_addr.SetOffset(offset - 1);
309           }
310         }
311       }
312     }
313 
314     if (m_sc.module_sp) {
315       // We have something in our stack frame symbol context, lets check
316       // if we haven't already tried to lookup one of those things. If we
317       // haven't then we will do the query.
318 
319       uint32_t actual_resolve_scope = 0;
320 
321       if (resolve_scope & eSymbolContextCompUnit) {
322         if (m_flags.IsClear(eSymbolContextCompUnit)) {
323           if (m_sc.comp_unit)
324             resolved |= eSymbolContextCompUnit;
325           else
326             actual_resolve_scope |= eSymbolContextCompUnit;
327         }
328       }
329 
330       if (resolve_scope & eSymbolContextFunction) {
331         if (m_flags.IsClear(eSymbolContextFunction)) {
332           if (m_sc.function)
333             resolved |= eSymbolContextFunction;
334           else
335             actual_resolve_scope |= eSymbolContextFunction;
336         }
337       }
338 
339       if (resolve_scope & eSymbolContextBlock) {
340         if (m_flags.IsClear(eSymbolContextBlock)) {
341           if (m_sc.block)
342             resolved |= eSymbolContextBlock;
343           else
344             actual_resolve_scope |= eSymbolContextBlock;
345         }
346       }
347 
348       if (resolve_scope & eSymbolContextSymbol) {
349         if (m_flags.IsClear(eSymbolContextSymbol)) {
350           if (m_sc.symbol)
351             resolved |= eSymbolContextSymbol;
352           else
353             actual_resolve_scope |= eSymbolContextSymbol;
354         }
355       }
356 
357       if (resolve_scope & eSymbolContextLineEntry) {
358         if (m_flags.IsClear(eSymbolContextLineEntry)) {
359           if (m_sc.line_entry.IsValid())
360             resolved |= eSymbolContextLineEntry;
361           else
362             actual_resolve_scope |= eSymbolContextLineEntry;
363         }
364       }
365 
366       if (actual_resolve_scope) {
367         // We might be resolving less information than what is already
368         // in our current symbol context so resolve into a temporary
369         // symbol context "sc" so we don't clear out data we have
370         // already found in "m_sc"
371         SymbolContext sc;
372         // Set flags that indicate what we have tried to resolve
373         resolved |= m_sc.module_sp->ResolveSymbolContextForAddress(
374             lookup_addr, actual_resolve_scope, sc);
375         // Only replace what we didn't already have as we may have
376         // information for an inlined function scope that won't match
377         // what a standard lookup by address would match
378         if ((resolved & eSymbolContextCompUnit) && m_sc.comp_unit == nullptr)
379           m_sc.comp_unit = sc.comp_unit;
380         if ((resolved & eSymbolContextFunction) && m_sc.function == nullptr)
381           m_sc.function = sc.function;
382         if ((resolved & eSymbolContextBlock) && m_sc.block == nullptr)
383           m_sc.block = sc.block;
384         if ((resolved & eSymbolContextSymbol) && m_sc.symbol == nullptr)
385           m_sc.symbol = sc.symbol;
386         if ((resolved & eSymbolContextLineEntry) &&
387             !m_sc.line_entry.IsValid()) {
388           m_sc.line_entry = sc.line_entry;
389           m_sc.line_entry.ApplyFileMappings(m_sc.target_sp);
390         }
391       }
392     } else {
393       // If we don't have a module, then we can't have the compile unit,
394       // function, block, line entry or symbol, so we can safely call
395       // ResolveSymbolContextForAddress with our symbol context member m_sc.
396       if (m_sc.target_sp) {
397         resolved |= m_sc.target_sp->GetImages().ResolveSymbolContextForAddress(
398             lookup_addr, resolve_scope, m_sc);
399       }
400     }
401 
402     // Update our internal flags so we remember what we have tried to locate so
403     // we don't have to keep trying when more calls to this function are made.
404     // We might have dug up more information that was requested (for example
405     // if we were asked to only get the block, we will have gotten the
406     // compile unit, and function) so set any additional bits that we resolved
407     m_flags.Set(resolve_scope | resolved);
408   }
409 
410   // Return the symbol context with everything that was possible to resolve
411   // resolved.
412   return m_sc;
413 }
414 
415 VariableList *StackFrame::GetVariableList(bool get_file_globals) {
416   std::lock_guard<std::recursive_mutex> guard(m_mutex);
417   if (m_flags.IsClear(RESOLVED_VARIABLES)) {
418     m_flags.Set(RESOLVED_VARIABLES);
419 
420     Block *frame_block = GetFrameBlock();
421 
422     if (frame_block) {
423       const bool get_child_variables = true;
424       const bool can_create = true;
425       const bool stop_if_child_block_is_inlined_function = true;
426       m_variable_list_sp.reset(new VariableList());
427       frame_block->AppendBlockVariables(can_create, get_child_variables,
428                                         stop_if_child_block_is_inlined_function,
429                                         [this](Variable *v) { return true; },
430                                         m_variable_list_sp.get());
431     }
432   }
433 
434   if (m_flags.IsClear(RESOLVED_GLOBAL_VARIABLES) && get_file_globals) {
435     m_flags.Set(RESOLVED_GLOBAL_VARIABLES);
436 
437     if (m_flags.IsClear(eSymbolContextCompUnit))
438       GetSymbolContext(eSymbolContextCompUnit);
439 
440     if (m_sc.comp_unit) {
441       VariableListSP global_variable_list_sp(
442           m_sc.comp_unit->GetVariableList(true));
443       if (m_variable_list_sp)
444         m_variable_list_sp->AddVariables(global_variable_list_sp.get());
445       else
446         m_variable_list_sp = global_variable_list_sp;
447     }
448   }
449 
450   return m_variable_list_sp.get();
451 }
452 
453 VariableListSP
454 StackFrame::GetInScopeVariableList(bool get_file_globals,
455                                    bool must_have_valid_location) {
456   std::lock_guard<std::recursive_mutex> guard(m_mutex);
457   // We can't fetch variable information for a history stack frame.
458   if (m_is_history_frame)
459     return VariableListSP();
460 
461   VariableListSP var_list_sp(new VariableList);
462   GetSymbolContext(eSymbolContextCompUnit | eSymbolContextBlock);
463 
464   if (m_sc.block) {
465     const bool can_create = true;
466     const bool get_parent_variables = true;
467     const bool stop_if_block_is_inlined_function = true;
468     m_sc.block->AppendVariables(
469         can_create, get_parent_variables, stop_if_block_is_inlined_function,
470         [this, must_have_valid_location](Variable *v) {
471           return v->IsInScope(this) && (!must_have_valid_location ||
472                                         v->LocationIsValidForFrame(this));
473         },
474         var_list_sp.get());
475   }
476 
477   if (m_sc.comp_unit && get_file_globals) {
478     VariableListSP global_variable_list_sp(
479         m_sc.comp_unit->GetVariableList(true));
480     if (global_variable_list_sp)
481       var_list_sp->AddVariables(global_variable_list_sp.get());
482   }
483 
484   return var_list_sp;
485 }
486 
487 ValueObjectSP StackFrame::GetValueForVariableExpressionPath(
488     const char *var_expr_cstr, DynamicValueType use_dynamic, uint32_t options,
489     VariableSP &var_sp, Error &error) {
490   // We can't fetch variable information for a history stack frame.
491   if (m_is_history_frame)
492     return ValueObjectSP();
493 
494   if (var_expr_cstr && var_expr_cstr[0]) {
495     const bool check_ptr_vs_member =
496         (options & eExpressionPathOptionCheckPtrVsMember) != 0;
497     const bool no_fragile_ivar =
498         (options & eExpressionPathOptionsNoFragileObjcIvar) != 0;
499     const bool no_synth_child =
500         (options & eExpressionPathOptionsNoSyntheticChildren) != 0;
501     // const bool no_synth_array = (options &
502     // eExpressionPathOptionsNoSyntheticArrayRange) != 0;
503     error.Clear();
504     bool deref = false;
505     bool address_of = false;
506     ValueObjectSP valobj_sp;
507     const bool get_file_globals = true;
508     // When looking up a variable for an expression, we need only consider the
509     // variables that are in scope.
510     VariableListSP var_list_sp(GetInScopeVariableList(get_file_globals));
511     VariableList *variable_list = var_list_sp.get();
512 
513     if (variable_list) {
514       // If first character is a '*', then show pointer contents
515       const char *var_expr = var_expr_cstr;
516       if (var_expr[0] == '*') {
517         deref = true;
518         var_expr++; // Skip the '*'
519       } else if (var_expr[0] == '&') {
520         address_of = true;
521         var_expr++; // Skip the '&'
522       }
523 
524       std::string var_path(var_expr);
525       size_t separator_idx = var_path.find_first_of(".-[=+~|&^%#@!/?,<>{}");
526       StreamString var_expr_path_strm;
527 
528       ConstString name_const_string;
529       if (separator_idx == std::string::npos)
530         name_const_string.SetCString(var_path.c_str());
531       else
532         name_const_string.SetCStringWithLength(var_path.c_str(), separator_idx);
533 
534       var_sp = variable_list->FindVariable(name_const_string, false);
535 
536       bool synthetically_added_instance_object = false;
537 
538       if (var_sp) {
539         var_path.erase(0, name_const_string.GetLength());
540       }
541 
542       if (!var_sp && (options & eExpressionPathOptionsAllowDirectIVarAccess)) {
543         // Check for direct ivars access which helps us with implicit
544         // access to ivars with the "this->" or "self->"
545         GetSymbolContext(eSymbolContextFunction | eSymbolContextBlock);
546         lldb::LanguageType method_language = eLanguageTypeUnknown;
547         bool is_instance_method = false;
548         ConstString method_object_name;
549         if (m_sc.GetFunctionMethodInfo(method_language, is_instance_method,
550                                        method_object_name)) {
551           if (is_instance_method && method_object_name) {
552             var_sp = variable_list->FindVariable(method_object_name);
553             if (var_sp) {
554               separator_idx = 0;
555               var_path.insert(0, "->");
556               synthetically_added_instance_object = true;
557             }
558           }
559         }
560       }
561 
562       if (!var_sp && (options & eExpressionPathOptionsInspectAnonymousUnions)) {
563         // Check if any anonymous unions are there which contain a variable with
564         // the name we need
565         for (size_t i = 0; i < variable_list->GetSize(); i++) {
566           if (VariableSP variable_sp = variable_list->GetVariableAtIndex(i)) {
567             if (variable_sp->GetName().IsEmpty()) {
568               if (Type *var_type = variable_sp->GetType()) {
569                 if (var_type->GetForwardCompilerType().IsAnonymousType()) {
570                   valobj_sp =
571                       GetValueObjectForFrameVariable(variable_sp, use_dynamic);
572                   if (!valobj_sp)
573                     return valobj_sp;
574                   valobj_sp = valobj_sp->GetChildMemberWithName(
575                       name_const_string, true);
576                   if (valobj_sp)
577                     break;
578                 }
579               }
580             }
581           }
582         }
583       }
584 
585       if (var_sp && !valobj_sp) {
586         valobj_sp = GetValueObjectForFrameVariable(var_sp, use_dynamic);
587         if (!valobj_sp)
588           return valobj_sp;
589       }
590       if (valobj_sp) {
591         // We are dumping at least one child
592         while (separator_idx != std::string::npos) {
593           // Calculate the next separator index ahead of time
594           ValueObjectSP child_valobj_sp;
595           const char separator_type = var_path[0];
596           switch (separator_type) {
597           case '-':
598             if (var_path.size() >= 2 && var_path[1] != '>')
599               return ValueObjectSP();
600 
601             if (no_fragile_ivar) {
602               // Make sure we aren't trying to deref an objective
603               // C ivar if this is not allowed
604               const uint32_t pointer_type_flags =
605                   valobj_sp->GetCompilerType().GetTypeInfo(nullptr);
606               if ((pointer_type_flags & eTypeIsObjC) &&
607                   (pointer_type_flags & eTypeIsPointer)) {
608                 // This was an objective C object pointer and
609                 // it was requested we skip any fragile ivars
610                 // so return nothing here
611                 return ValueObjectSP();
612               }
613             }
614             var_path.erase(0, 1); // Remove the '-'
615             LLVM_FALLTHROUGH;
616           case '.': {
617             const bool expr_is_ptr = var_path[0] == '>';
618 
619             var_path.erase(0, 1); // Remove the '.' or '>'
620             separator_idx = var_path.find_first_of(".-[");
621             ConstString child_name;
622             if (separator_idx == std::string::npos)
623               child_name.SetCString(var_path.c_str());
624             else
625               child_name.SetCStringWithLength(var_path.c_str(), separator_idx);
626 
627             if (check_ptr_vs_member) {
628               // We either have a pointer type and need to verify
629               // valobj_sp is a pointer, or we have a member of a
630               // class/union/struct being accessed with the . syntax
631               // and need to verify we don't have a pointer.
632               const bool actual_is_ptr = valobj_sp->IsPointerType();
633 
634               if (actual_is_ptr != expr_is_ptr) {
635                 // Incorrect use of "." with a pointer, or "->" with
636                 // a class/union/struct instance or reference.
637                 valobj_sp->GetExpressionPath(var_expr_path_strm, false);
638                 if (actual_is_ptr)
639                   error.SetErrorStringWithFormat(
640                       "\"%s\" is a pointer and . was used to attempt to access "
641                       "\"%s\". Did you mean \"%s->%s\"?",
642                       var_expr_path_strm.GetString().c_str(),
643                       child_name.GetCString(),
644                       var_expr_path_strm.GetString().c_str(), var_path.c_str());
645                 else
646                   error.SetErrorStringWithFormat(
647                       "\"%s\" is not a pointer and -> was used to attempt to "
648                       "access \"%s\". Did you mean \"%s.%s\"?",
649                       var_expr_path_strm.GetString().c_str(),
650                       child_name.GetCString(),
651                       var_expr_path_strm.GetString().c_str(), var_path.c_str());
652                 return ValueObjectSP();
653               }
654             }
655             child_valobj_sp =
656                 valobj_sp->GetChildMemberWithName(child_name, true);
657             if (!child_valobj_sp) {
658               if (!no_synth_child) {
659                 child_valobj_sp = valobj_sp->GetSyntheticValue();
660                 if (child_valobj_sp)
661                   child_valobj_sp =
662                       child_valobj_sp->GetChildMemberWithName(child_name, true);
663               }
664 
665               if (no_synth_child || !child_valobj_sp) {
666                 // No child member with name "child_name"
667                 if (synthetically_added_instance_object) {
668                   // We added a "this->" or "self->" to the beginning of the
669                   // expression
670                   // and this is the first pointer ivar access, so just return
671                   // the normal
672                   // error
673                   error.SetErrorStringWithFormat(
674                       "no variable or instance variable named '%s' found in "
675                       "this frame",
676                       name_const_string.GetCString());
677                 } else {
678                   valobj_sp->GetExpressionPath(var_expr_path_strm, false);
679                   if (child_name) {
680                     error.SetErrorStringWithFormat(
681                         "\"%s\" is not a member of \"(%s) %s\"",
682                         child_name.GetCString(),
683                         valobj_sp->GetTypeName().AsCString("<invalid type>"),
684                         var_expr_path_strm.GetString().c_str());
685                   } else {
686                     error.SetErrorStringWithFormat(
687                         "incomplete expression path after \"%s\" in \"%s\"",
688                         var_expr_path_strm.GetString().c_str(), var_expr_cstr);
689                   }
690                 }
691                 return ValueObjectSP();
692               }
693             }
694             synthetically_added_instance_object = false;
695             // Remove the child name from the path
696             var_path.erase(0, child_name.GetLength());
697             if (use_dynamic != eNoDynamicValues) {
698               ValueObjectSP dynamic_value_sp(
699                   child_valobj_sp->GetDynamicValue(use_dynamic));
700               if (dynamic_value_sp)
701                 child_valobj_sp = dynamic_value_sp;
702             }
703           } break;
704 
705           case '[':
706             // Array member access, or treating pointer as an array
707             if (var_path.size() > 2) // Need at least two brackets and a number
708             {
709               char *end = nullptr;
710               long child_index = ::strtol(&var_path[1], &end, 0);
711               if (end && *end == ']' &&
712                   *(end - 1) != '[') // this code forces an error in the case of
713                                      // arr[]. as bitfield[] is not a good
714                                      // syntax we're good to go
715               {
716                 if (valobj_sp->GetCompilerType().IsPointerToScalarType() &&
717                     deref) {
718                   // what we have is *ptr[low]. the most similar C++ syntax is
719                   // to deref ptr
720                   // and extract bit low out of it. reading array item low
721                   // would be done by saying ptr[low], without a deref * sign
722                   Error error;
723                   ValueObjectSP temp(valobj_sp->Dereference(error));
724                   if (error.Fail()) {
725                     valobj_sp->GetExpressionPath(var_expr_path_strm, false);
726                     error.SetErrorStringWithFormat(
727                         "could not dereference \"(%s) %s\"",
728                         valobj_sp->GetTypeName().AsCString("<invalid type>"),
729                         var_expr_path_strm.GetString().c_str());
730                     return ValueObjectSP();
731                   }
732                   valobj_sp = temp;
733                   deref = false;
734                 } else if (valobj_sp->GetCompilerType().IsArrayOfScalarType() &&
735                            deref) {
736                   // what we have is *arr[low]. the most similar C++ syntax is
737                   // to get arr[0]
738                   // (an operation that is equivalent to deref-ing arr)
739                   // and extract bit low out of it. reading array item low
740                   // would be done by saying arr[low], without a deref * sign
741                   Error error;
742                   ValueObjectSP temp(valobj_sp->GetChildAtIndex(0, true));
743                   if (error.Fail()) {
744                     valobj_sp->GetExpressionPath(var_expr_path_strm, false);
745                     error.SetErrorStringWithFormat(
746                         "could not get item 0 for \"(%s) %s\"",
747                         valobj_sp->GetTypeName().AsCString("<invalid type>"),
748                         var_expr_path_strm.GetString().c_str());
749                     return ValueObjectSP();
750                   }
751                   valobj_sp = temp;
752                   deref = false;
753                 }
754 
755                 bool is_incomplete_array = false;
756                 if (valobj_sp->IsPointerType()) {
757                   bool is_objc_pointer = true;
758 
759                   if (valobj_sp->GetCompilerType().GetMinimumLanguage() !=
760                       eLanguageTypeObjC)
761                     is_objc_pointer = false;
762                   else if (!valobj_sp->GetCompilerType().IsPointerType())
763                     is_objc_pointer = false;
764 
765                   if (no_synth_child && is_objc_pointer) {
766                     error.SetErrorStringWithFormat(
767                         "\"(%s) %s\" is an Objective-C pointer, and cannot be "
768                         "subscripted",
769                         valobj_sp->GetTypeName().AsCString("<invalid type>"),
770                         var_expr_path_strm.GetString().c_str());
771 
772                     return ValueObjectSP();
773                   } else if (is_objc_pointer) {
774                     // dereferencing ObjC variables is not valid.. so let's try
775                     // and recur to synthetic children
776                     ValueObjectSP synthetic = valobj_sp->GetSyntheticValue();
777                     if (!synthetic                 /* no synthetic */
778                         || synthetic == valobj_sp) /* synthetic is the same as
779                                                       the original object */
780                     {
781                       valobj_sp->GetExpressionPath(var_expr_path_strm, false);
782                       error.SetErrorStringWithFormat(
783                           "\"(%s) %s\" is not an array type",
784                           valobj_sp->GetTypeName().AsCString("<invalid type>"),
785                           var_expr_path_strm.GetString().c_str());
786                     } else if (
787                         static_cast<uint32_t>(child_index) >=
788                         synthetic
789                             ->GetNumChildren() /* synthetic does not have that many values */) {
790                       valobj_sp->GetExpressionPath(var_expr_path_strm, false);
791                       error.SetErrorStringWithFormat(
792                           "array index %ld is not valid for \"(%s) %s\"",
793                           child_index,
794                           valobj_sp->GetTypeName().AsCString("<invalid type>"),
795                           var_expr_path_strm.GetString().c_str());
796                     } else {
797                       child_valobj_sp =
798                           synthetic->GetChildAtIndex(child_index, true);
799                       if (!child_valobj_sp) {
800                         valobj_sp->GetExpressionPath(var_expr_path_strm, false);
801                         error.SetErrorStringWithFormat(
802                             "array index %ld is not valid for \"(%s) %s\"",
803                             child_index, valobj_sp->GetTypeName().AsCString(
804                                              "<invalid type>"),
805                             var_expr_path_strm.GetString().c_str());
806                       }
807                     }
808                   } else {
809                     child_valobj_sp =
810                         valobj_sp->GetSyntheticArrayMember(child_index, true);
811                     if (!child_valobj_sp) {
812                       valobj_sp->GetExpressionPath(var_expr_path_strm, false);
813                       error.SetErrorStringWithFormat(
814                           "failed to use pointer as array for index %ld for "
815                           "\"(%s) %s\"",
816                           child_index,
817                           valobj_sp->GetTypeName().AsCString("<invalid type>"),
818                           var_expr_path_strm.GetString().c_str());
819                     }
820                   }
821                 } else if (valobj_sp->GetCompilerType().IsArrayType(
822                                nullptr, nullptr, &is_incomplete_array)) {
823                   // Pass false to dynamic_value here so we can tell the
824                   // difference between
825                   // no dynamic value and no member of this type...
826                   child_valobj_sp =
827                       valobj_sp->GetChildAtIndex(child_index, true);
828                   if (!child_valobj_sp &&
829                       (is_incomplete_array || !no_synth_child))
830                     child_valobj_sp =
831                         valobj_sp->GetSyntheticArrayMember(child_index, true);
832 
833                   if (!child_valobj_sp) {
834                     valobj_sp->GetExpressionPath(var_expr_path_strm, false);
835                     error.SetErrorStringWithFormat(
836                         "array index %ld is not valid for \"(%s) %s\"",
837                         child_index,
838                         valobj_sp->GetTypeName().AsCString("<invalid type>"),
839                         var_expr_path_strm.GetString().c_str());
840                   }
841                 } else if (valobj_sp->GetCompilerType().IsScalarType()) {
842                   // this is a bitfield asking to display just one bit
843                   child_valobj_sp = valobj_sp->GetSyntheticBitFieldChild(
844                       child_index, child_index, true);
845                   if (!child_valobj_sp) {
846                     valobj_sp->GetExpressionPath(var_expr_path_strm, false);
847                     error.SetErrorStringWithFormat(
848                         "bitfield range %ld-%ld is not valid for \"(%s) %s\"",
849                         child_index, child_index,
850                         valobj_sp->GetTypeName().AsCString("<invalid type>"),
851                         var_expr_path_strm.GetString().c_str());
852                   }
853                 } else {
854                   ValueObjectSP synthetic = valobj_sp->GetSyntheticValue();
855                   if (no_synth_child /* synthetic is forbidden */ ||
856                       !synthetic /* no synthetic */
857                       ||
858                       synthetic == valobj_sp) /* synthetic is the same as the
859                                                  original object */
860                   {
861                     valobj_sp->GetExpressionPath(var_expr_path_strm, false);
862                     error.SetErrorStringWithFormat(
863                         "\"(%s) %s\" is not an array type",
864                         valobj_sp->GetTypeName().AsCString("<invalid type>"),
865                         var_expr_path_strm.GetString().c_str());
866                   } else if (
867                       static_cast<uint32_t>(child_index) >=
868                       synthetic
869                           ->GetNumChildren() /* synthetic does not have that many values */) {
870                     valobj_sp->GetExpressionPath(var_expr_path_strm, false);
871                     error.SetErrorStringWithFormat(
872                         "array index %ld is not valid for \"(%s) %s\"",
873                         child_index,
874                         valobj_sp->GetTypeName().AsCString("<invalid type>"),
875                         var_expr_path_strm.GetString().c_str());
876                   } else {
877                     child_valobj_sp =
878                         synthetic->GetChildAtIndex(child_index, true);
879                     if (!child_valobj_sp) {
880                       valobj_sp->GetExpressionPath(var_expr_path_strm, false);
881                       error.SetErrorStringWithFormat(
882                           "array index %ld is not valid for \"(%s) %s\"",
883                           child_index,
884                           valobj_sp->GetTypeName().AsCString("<invalid type>"),
885                           var_expr_path_strm.GetString().c_str());
886                     }
887                   }
888                 }
889 
890                 if (!child_valobj_sp) {
891                   // Invalid array index...
892                   return ValueObjectSP();
893                 }
894 
895                 // Erase the array member specification '[%i]' where
896                 // %i is the array index
897                 var_path.erase(0, (end - var_path.c_str()) + 1);
898                 separator_idx = var_path.find_first_of(".-[");
899                 if (use_dynamic != eNoDynamicValues) {
900                   ValueObjectSP dynamic_value_sp(
901                       child_valobj_sp->GetDynamicValue(use_dynamic));
902                   if (dynamic_value_sp)
903                     child_valobj_sp = dynamic_value_sp;
904                 }
905                 // Break out early from the switch since we were
906                 // able to find the child member
907                 break;
908               } else if (end && *end == '-') {
909                 // this is most probably a BitField, let's take a look
910                 char *real_end = nullptr;
911                 long final_index = ::strtol(end + 1, &real_end, 0);
912                 bool expand_bitfield = true;
913                 if (real_end && *real_end == ']') {
914                   // if the format given is [high-low], swap range
915                   if (child_index > final_index) {
916                     long temp = child_index;
917                     child_index = final_index;
918                     final_index = temp;
919                   }
920 
921                   if (valobj_sp->GetCompilerType().IsPointerToScalarType() &&
922                       deref) {
923                     // what we have is *ptr[low-high]. the most similar C++
924                     // syntax is to deref ptr
925                     // and extract bits low thru high out of it. reading array
926                     // items low thru high
927                     // would be done by saying ptr[low-high], without a deref *
928                     // sign
929                     Error error;
930                     ValueObjectSP temp(valobj_sp->Dereference(error));
931                     if (error.Fail()) {
932                       valobj_sp->GetExpressionPath(var_expr_path_strm, false);
933                       error.SetErrorStringWithFormat(
934                           "could not dereference \"(%s) %s\"",
935                           valobj_sp->GetTypeName().AsCString("<invalid type>"),
936                           var_expr_path_strm.GetString().c_str());
937                       return ValueObjectSP();
938                     }
939                     valobj_sp = temp;
940                     deref = false;
941                   } else if (valobj_sp->GetCompilerType()
942                                  .IsArrayOfScalarType() &&
943                              deref) {
944                     // what we have is *arr[low-high]. the most similar C++
945                     // syntax is to get arr[0]
946                     // (an operation that is equivalent to deref-ing arr)
947                     // and extract bits low thru high out of it. reading array
948                     // items low thru high
949                     // would be done by saying arr[low-high], without a deref *
950                     // sign
951                     Error error;
952                     ValueObjectSP temp(valobj_sp->GetChildAtIndex(0, true));
953                     if (error.Fail()) {
954                       valobj_sp->GetExpressionPath(var_expr_path_strm, false);
955                       error.SetErrorStringWithFormat(
956                           "could not get item 0 for \"(%s) %s\"",
957                           valobj_sp->GetTypeName().AsCString("<invalid type>"),
958                           var_expr_path_strm.GetString().c_str());
959                       return ValueObjectSP();
960                     }
961                     valobj_sp = temp;
962                     deref = false;
963                   }
964                   /*else if (valobj_sp->IsArrayType() ||
965                   valobj_sp->IsPointerType())
966                   {
967                       child_valobj_sp =
968                   valobj_sp->GetSyntheticArrayRangeChild(child_index,
969                   final_index, true);
970                       expand_bitfield = false;
971                       if (!child_valobj_sp)
972                       {
973                           valobj_sp->GetExpressionPath (var_expr_path_strm,
974                   false);
975                           error.SetErrorStringWithFormat ("array range %i-%i is
976                   not valid for \"(%s) %s\"",
977                                                           child_index,
978                   final_index,
979                                                           valobj_sp->GetTypeName().AsCString("<invalid
980                   type>"),
981                                                           var_expr_path_strm.GetString().c_str());
982                       }
983                   }*/
984 
985                   if (expand_bitfield) {
986                     child_valobj_sp = valobj_sp->GetSyntheticBitFieldChild(
987                         child_index, final_index, true);
988                     if (!child_valobj_sp) {
989                       valobj_sp->GetExpressionPath(var_expr_path_strm, false);
990                       error.SetErrorStringWithFormat(
991                           "bitfield range %ld-%ld is not valid for \"(%s) %s\"",
992                           child_index, final_index,
993                           valobj_sp->GetTypeName().AsCString("<invalid type>"),
994                           var_expr_path_strm.GetString().c_str());
995                     }
996                   }
997                 }
998 
999                 if (!child_valobj_sp) {
1000                   // Invalid bitfield range...
1001                   return ValueObjectSP();
1002                 }
1003 
1004                 // Erase the bitfield member specification '[%i-%i]' where
1005                 // %i is the index
1006                 var_path.erase(0, (real_end - var_path.c_str()) + 1);
1007                 separator_idx = var_path.find_first_of(".-[");
1008                 if (use_dynamic != eNoDynamicValues) {
1009                   ValueObjectSP dynamic_value_sp(
1010                       child_valobj_sp->GetDynamicValue(use_dynamic));
1011                   if (dynamic_value_sp)
1012                     child_valobj_sp = dynamic_value_sp;
1013                 }
1014                 // Break out early from the switch since we were
1015                 // able to find the child member
1016                 break;
1017               }
1018             } else {
1019               error.SetErrorStringWithFormat(
1020                   "invalid square bracket encountered after \"%s\" in \"%s\"",
1021                   var_expr_path_strm.GetString().c_str(), var_path.c_str());
1022             }
1023             return ValueObjectSP();
1024 
1025           default:
1026             // Failure...
1027             {
1028               valobj_sp->GetExpressionPath(var_expr_path_strm, false);
1029               error.SetErrorStringWithFormat(
1030                   "unexpected char '%c' encountered after \"%s\" in \"%s\"",
1031                   separator_type, var_expr_path_strm.GetString().c_str(),
1032                   var_path.c_str());
1033 
1034               return ValueObjectSP();
1035             }
1036           }
1037 
1038           if (child_valobj_sp)
1039             valobj_sp = child_valobj_sp;
1040 
1041           if (var_path.empty())
1042             break;
1043         }
1044         if (valobj_sp) {
1045           if (deref) {
1046             ValueObjectSP deref_valobj_sp(valobj_sp->Dereference(error));
1047             valobj_sp = deref_valobj_sp;
1048           } else if (address_of) {
1049             ValueObjectSP address_of_valobj_sp(valobj_sp->AddressOf(error));
1050             valobj_sp = address_of_valobj_sp;
1051           }
1052         }
1053         return valobj_sp;
1054       } else {
1055         error.SetErrorStringWithFormat(
1056             "no variable named '%s' found in this frame",
1057             name_const_string.GetCString());
1058       }
1059     }
1060   } else {
1061     error.SetErrorStringWithFormat("invalid variable path '%s'", var_expr_cstr);
1062   }
1063   return ValueObjectSP();
1064 }
1065 
1066 bool StackFrame::GetFrameBaseValue(Scalar &frame_base, Error *error_ptr) {
1067   std::lock_guard<std::recursive_mutex> guard(m_mutex);
1068   if (!m_cfa_is_valid) {
1069     m_frame_base_error.SetErrorString(
1070         "No frame base available for this historical stack frame.");
1071     return false;
1072   }
1073 
1074   if (m_flags.IsClear(GOT_FRAME_BASE)) {
1075     if (m_sc.function) {
1076       m_frame_base.Clear();
1077       m_frame_base_error.Clear();
1078 
1079       m_flags.Set(GOT_FRAME_BASE);
1080       ExecutionContext exe_ctx(shared_from_this());
1081       Value expr_value;
1082       addr_t loclist_base_addr = LLDB_INVALID_ADDRESS;
1083       if (m_sc.function->GetFrameBaseExpression().IsLocationList())
1084         loclist_base_addr =
1085             m_sc.function->GetAddressRange().GetBaseAddress().GetLoadAddress(
1086                 exe_ctx.GetTargetPtr());
1087 
1088       if (m_sc.function->GetFrameBaseExpression().Evaluate(
1089               &exe_ctx, nullptr, nullptr, nullptr, loclist_base_addr, nullptr,
1090               nullptr, expr_value, &m_frame_base_error) == false) {
1091         // We should really have an error if evaluate returns, but in case
1092         // we don't, lets set the error to something at least.
1093         if (m_frame_base_error.Success())
1094           m_frame_base_error.SetErrorString(
1095               "Evaluation of the frame base expression failed.");
1096       } else {
1097         m_frame_base = expr_value.ResolveValue(&exe_ctx);
1098       }
1099     } else {
1100       m_frame_base_error.SetErrorString("No function in symbol context.");
1101     }
1102   }
1103 
1104   if (m_frame_base_error.Success())
1105     frame_base = m_frame_base;
1106 
1107   if (error_ptr)
1108     *error_ptr = m_frame_base_error;
1109   return m_frame_base_error.Success();
1110 }
1111 
1112 DWARFExpression *StackFrame::GetFrameBaseExpression(Error *error_ptr) {
1113   if (!m_sc.function) {
1114     if (error_ptr) {
1115       error_ptr->SetErrorString("No function in symbol context.");
1116     }
1117     return nullptr;
1118   }
1119 
1120   return &m_sc.function->GetFrameBaseExpression();
1121 }
1122 
1123 RegisterContextSP StackFrame::GetRegisterContext() {
1124   std::lock_guard<std::recursive_mutex> guard(m_mutex);
1125   if (!m_reg_context_sp) {
1126     ThreadSP thread_sp(GetThread());
1127     if (thread_sp)
1128       m_reg_context_sp = thread_sp->CreateRegisterContextForFrame(this);
1129   }
1130   return m_reg_context_sp;
1131 }
1132 
1133 bool StackFrame::HasDebugInformation() {
1134   GetSymbolContext(eSymbolContextLineEntry);
1135   return m_sc.line_entry.IsValid();
1136 }
1137 
1138 ValueObjectSP
1139 StackFrame::GetValueObjectForFrameVariable(const VariableSP &variable_sp,
1140                                            DynamicValueType use_dynamic) {
1141   std::lock_guard<std::recursive_mutex> guard(m_mutex);
1142   ValueObjectSP valobj_sp;
1143   if (m_is_history_frame) {
1144     return valobj_sp;
1145   }
1146   VariableList *var_list = GetVariableList(true);
1147   if (var_list) {
1148     // Make sure the variable is a frame variable
1149     const uint32_t var_idx = var_list->FindIndexForVariable(variable_sp.get());
1150     const uint32_t num_variables = var_list->GetSize();
1151     if (var_idx < num_variables) {
1152       valobj_sp = m_variable_list_value_objects.GetValueObjectAtIndex(var_idx);
1153       if (!valobj_sp) {
1154         if (m_variable_list_value_objects.GetSize() < num_variables)
1155           m_variable_list_value_objects.Resize(num_variables);
1156         valobj_sp = ValueObjectVariable::Create(this, variable_sp);
1157         m_variable_list_value_objects.SetValueObjectAtIndex(var_idx, valobj_sp);
1158       }
1159     }
1160   }
1161   if (use_dynamic != eNoDynamicValues && valobj_sp) {
1162     ValueObjectSP dynamic_sp = valobj_sp->GetDynamicValue(use_dynamic);
1163     if (dynamic_sp)
1164       return dynamic_sp;
1165   }
1166   return valobj_sp;
1167 }
1168 
1169 ValueObjectSP StackFrame::TrackGlobalVariable(const VariableSP &variable_sp,
1170                                               DynamicValueType use_dynamic) {
1171   std::lock_guard<std::recursive_mutex> guard(m_mutex);
1172   if (m_is_history_frame)
1173     return ValueObjectSP();
1174 
1175   // Check to make sure we aren't already tracking this variable?
1176   ValueObjectSP valobj_sp(
1177       GetValueObjectForFrameVariable(variable_sp, use_dynamic));
1178   if (!valobj_sp) {
1179     // We aren't already tracking this global
1180     VariableList *var_list = GetVariableList(true);
1181     // If this frame has no variables, create a new list
1182     if (var_list == nullptr)
1183       m_variable_list_sp.reset(new VariableList());
1184 
1185     // Add the global/static variable to this frame
1186     m_variable_list_sp->AddVariable(variable_sp);
1187 
1188     // Now make a value object for it so we can track its changes
1189     valobj_sp = GetValueObjectForFrameVariable(variable_sp, use_dynamic);
1190   }
1191   return valobj_sp;
1192 }
1193 
1194 bool StackFrame::IsInlined() {
1195   if (m_sc.block == nullptr)
1196     GetSymbolContext(eSymbolContextBlock);
1197   if (m_sc.block)
1198     return m_sc.block->GetContainingInlinedBlock() != nullptr;
1199   return false;
1200 }
1201 
1202 lldb::LanguageType StackFrame::GetLanguage() {
1203   CompileUnit *cu = GetSymbolContext(eSymbolContextCompUnit).comp_unit;
1204   if (cu)
1205     return cu->GetLanguage();
1206   return lldb::eLanguageTypeUnknown;
1207 }
1208 
1209 lldb::LanguageType StackFrame::GuessLanguage() {
1210   LanguageType lang_type = GetLanguage();
1211 
1212   if (lang_type == eLanguageTypeUnknown) {
1213     Function *f = GetSymbolContext(eSymbolContextFunction).function;
1214     if (f) {
1215       lang_type = f->GetMangled().GuessLanguage();
1216     }
1217   }
1218 
1219   return lang_type;
1220 }
1221 
1222 namespace {
1223 std::pair<const Instruction::Operand *, int64_t>
1224 GetBaseExplainingValue(const Instruction::Operand &operand,
1225                        RegisterContext &register_context, lldb::addr_t value) {
1226   switch (operand.m_type) {
1227   case Instruction::Operand::Type::Dereference:
1228   case Instruction::Operand::Type::Immediate:
1229   case Instruction::Operand::Type::Invalid:
1230   case Instruction::Operand::Type::Product:
1231     // These are not currently interesting
1232     return std::make_pair(nullptr, 0);
1233   case Instruction::Operand::Type::Sum: {
1234     const Instruction::Operand *immediate_child = nullptr;
1235     const Instruction::Operand *variable_child = nullptr;
1236     if (operand.m_children[0].m_type == Instruction::Operand::Type::Immediate) {
1237       immediate_child = &operand.m_children[0];
1238       variable_child = &operand.m_children[1];
1239     } else if (operand.m_children[1].m_type ==
1240                Instruction::Operand::Type::Immediate) {
1241       immediate_child = &operand.m_children[1];
1242       variable_child = &operand.m_children[0];
1243     }
1244     if (!immediate_child) {
1245       return std::make_pair(nullptr, 0);
1246     }
1247     lldb::addr_t adjusted_value = value;
1248     if (immediate_child->m_negative) {
1249       adjusted_value += immediate_child->m_immediate;
1250     } else {
1251       adjusted_value -= immediate_child->m_immediate;
1252     }
1253     std::pair<const Instruction::Operand *, int64_t> base_and_offset =
1254         GetBaseExplainingValue(*variable_child, register_context,
1255                                adjusted_value);
1256     if (!base_and_offset.first) {
1257       return std::make_pair(nullptr, 0);
1258     }
1259     if (immediate_child->m_negative) {
1260       base_and_offset.second -= immediate_child->m_immediate;
1261     } else {
1262       base_and_offset.second += immediate_child->m_immediate;
1263     }
1264     return base_and_offset;
1265   }
1266   case Instruction::Operand::Type::Register: {
1267     const RegisterInfo *info =
1268         register_context.GetRegisterInfoByName(operand.m_register.AsCString());
1269     if (!info) {
1270       return std::make_pair(nullptr, 0);
1271     }
1272     RegisterValue reg_value;
1273     if (!register_context.ReadRegister(info, reg_value)) {
1274       return std::make_pair(nullptr, 0);
1275     }
1276     if (reg_value.GetAsUInt64() == value) {
1277       return std::make_pair(&operand, 0);
1278     } else {
1279       return std::make_pair(nullptr, 0);
1280     }
1281   }
1282   }
1283 }
1284 
1285 std::pair<const Instruction::Operand *, int64_t>
1286 GetBaseExplainingDereference(const Instruction::Operand &operand,
1287                              RegisterContext &register_context,
1288                              lldb::addr_t addr) {
1289   if (operand.m_type == Instruction::Operand::Type::Dereference) {
1290     return GetBaseExplainingValue(operand.m_children[0], register_context,
1291                                   addr);
1292   }
1293   return std::make_pair(nullptr, 0);
1294 }
1295 };
1296 
1297 lldb::ValueObjectSP StackFrame::GuessValueForAddress(lldb::addr_t addr) {
1298   TargetSP target_sp = CalculateTarget();
1299 
1300   const ArchSpec &target_arch = target_sp->GetArchitecture();
1301 
1302   AddressRange pc_range;
1303   pc_range.GetBaseAddress() = GetFrameCodeAddress();
1304   pc_range.SetByteSize(target_arch.GetMaximumOpcodeByteSize());
1305 
1306   ExecutionContext exe_ctx(shared_from_this());
1307 
1308   const char *plugin_name = nullptr;
1309   const char *flavor = nullptr;
1310   const bool prefer_file_cache = false;
1311 
1312   DisassemblerSP disassembler_sp = Disassembler::DisassembleRange(
1313       target_arch, plugin_name, flavor, exe_ctx, pc_range, prefer_file_cache);
1314 
1315   if (!disassembler_sp->GetInstructionList().GetSize()) {
1316     return ValueObjectSP();
1317   }
1318 
1319   InstructionSP instruction_sp =
1320       disassembler_sp->GetInstructionList().GetInstructionAtIndex(0);
1321 
1322   llvm::SmallVector<Instruction::Operand, 3> operands;
1323 
1324   if (!instruction_sp->ParseOperands(operands)) {
1325     return ValueObjectSP();
1326   }
1327 
1328   RegisterContextSP register_context_sp = GetRegisterContext();
1329 
1330   if (!register_context_sp) {
1331     return ValueObjectSP();
1332   }
1333 
1334   for (const Instruction::Operand &operand : operands) {
1335     std::pair<const Instruction::Operand *, int64_t> base_and_offset =
1336         GetBaseExplainingDereference(operand, *register_context_sp, addr);
1337 
1338     if (!base_and_offset.first) {
1339       continue;
1340     }
1341 
1342     switch (base_and_offset.first->m_type) {
1343     case Instruction::Operand::Type::Immediate: {
1344       lldb_private::Address addr;
1345       if (target_sp->ResolveLoadAddress(base_and_offset.first->m_immediate +
1346                                             base_and_offset.second,
1347                                         addr)) {
1348         TypeSystem *c_type_system =
1349             target_sp->GetScratchTypeSystemForLanguage(nullptr, eLanguageTypeC);
1350         if (!c_type_system) {
1351           return ValueObjectSP();
1352         } else {
1353           CompilerType void_ptr_type =
1354               c_type_system
1355                   ->GetBasicTypeFromAST(lldb::BasicType::eBasicTypeChar)
1356                   .GetPointerType();
1357           return ValueObjectMemory::Create(this, "", addr, void_ptr_type);
1358         }
1359       } else {
1360         return ValueObjectSP();
1361       }
1362       break;
1363     }
1364     case Instruction::Operand::Type::Register: {
1365       return GuessValueForRegisterAndOffset(base_and_offset.first->m_register,
1366                                             base_and_offset.second);
1367     }
1368     default:
1369       return ValueObjectSP();
1370     }
1371   }
1372 
1373   return ValueObjectSP();
1374 }
1375 
1376 namespace {
1377 ValueObjectSP GetValueForOffset(StackFrame &frame, ValueObjectSP &parent,
1378                                 int64_t offset) {
1379   if (offset < 0 || uint64_t(offset) >= parent->GetByteSize()) {
1380     return ValueObjectSP();
1381   }
1382 
1383   if (parent->IsPointerOrReferenceType()) {
1384     return parent;
1385   }
1386 
1387   for (int ci = 0, ce = parent->GetNumChildren(); ci != ce; ++ci) {
1388     const bool can_create = true;
1389     ValueObjectSP child_sp = parent->GetChildAtIndex(ci, can_create);
1390 
1391     if (!child_sp) {
1392       return ValueObjectSP();
1393     }
1394 
1395     int64_t child_offset = child_sp->GetByteOffset();
1396     int64_t child_size = child_sp->GetByteSize();
1397 
1398     if (offset >= child_offset && offset < (child_offset + child_size)) {
1399       return GetValueForOffset(frame, child_sp, offset - child_offset);
1400     }
1401   }
1402 
1403   if (offset == 0) {
1404     return parent;
1405   } else {
1406     return ValueObjectSP();
1407   }
1408 }
1409 
1410 ValueObjectSP GetValueForDereferincingOffset(StackFrame &frame,
1411                                              ValueObjectSP &base,
1412                                              int64_t offset) {
1413   // base is a pointer to something
1414   // offset is the thing to add to the pointer
1415   // We return the most sensible ValueObject for the result of *(base+offset)
1416 
1417   if (!base->IsPointerOrReferenceType()) {
1418     return ValueObjectSP();
1419   }
1420 
1421   Error error;
1422   ValueObjectSP pointee = base->Dereference(error);
1423 
1424   if (offset >= pointee->GetByteSize()) {
1425     int64_t index = offset / pointee->GetByteSize();
1426     offset = offset % pointee->GetByteSize();
1427     const bool can_create = true;
1428     pointee = base->GetSyntheticArrayMember(index, can_create);
1429   }
1430 
1431   if (!pointee || error.Fail()) {
1432     return ValueObjectSP();
1433   }
1434 
1435   return GetValueForOffset(frame, pointee, offset);
1436 }
1437 
1438 //------------------------------------------------------------------
1439 /// Attempt to reconstruct the ValueObject for the address contained in a
1440 /// given register plus an offset.
1441 ///
1442 /// @params [in] frame
1443 ///   The current stack frame.
1444 ///
1445 /// @params [in] reg
1446 ///   The register.
1447 ///
1448 /// @params [in] offset
1449 ///   The offset from the register.
1450 ///
1451 /// @param [in] disassembler
1452 ///   A disassembler containing instructions valid up to the current PC.
1453 ///
1454 /// @param [in] variables
1455 ///   The variable list from the current frame,
1456 ///
1457 /// @param [in] pc
1458 ///   The program counter for the instruction considered the 'user'.
1459 ///
1460 /// @return
1461 ///   A string describing the base for the ExpressionPath.  This could be a
1462 ///     variable, a register value, an argument, or a function return value.
1463 ///   The ValueObject if found.  If valid, it has a valid ExpressionPath.
1464 //------------------------------------------------------------------
1465 lldb::ValueObjectSP DoGuessValueAt(StackFrame &frame, ConstString reg,
1466                                    int64_t offset, Disassembler &disassembler,
1467                                    VariableList &variables, const Address &pc) {
1468   // Example of operation for Intel:
1469   //
1470   // +14: movq   -0x8(%rbp), %rdi
1471   // +18: movq   0x8(%rdi), %rdi
1472   // +22: addl   0x4(%rdi), %eax
1473   //
1474   // f, a pointer to a struct, is known to be at -0x8(%rbp).
1475   //
1476   // DoGuessValueAt(frame, rdi, 4, dis, vars, 0x22) finds the instruction at +18
1477   // that assigns to rdi, and calls itself recursively for that dereference
1478   //   DoGuessValueAt(frame, rdi, 8, dis, vars, 0x18) finds the instruction at
1479   //   +14 that assigns to rdi, and calls itself recursively for that
1480   //   derefernece
1481   //     DoGuessValueAt(frame, rbp, -8, dis, vars, 0x14) finds "f" in the
1482   //     variable list.
1483   //     Returns a ValueObject for f.  (That's what was stored at rbp-8 at +14)
1484   //   Returns a ValueObject for *(f+8) or f->b (That's what was stored at rdi+8
1485   //   at +18)
1486   // Returns a ValueObject for *(f->b+4) or f->b->a (That's what was stored at
1487   // rdi+4 at +22)
1488 
1489   // First, check the variable list to see if anything is at the specified
1490   // location.
1491   for (size_t vi = 0, ve = variables.GetSize(); vi != ve; ++vi) {
1492     VariableSP var_sp = variables.GetVariableAtIndex(vi);
1493     DWARFExpression &dwarf_expression = var_sp->LocationExpression();
1494 
1495     const RegisterInfo *expression_reg;
1496     int64_t expression_offset;
1497     ExecutionContext exe_ctx;
1498 
1499     if (dwarf_expression.IsDereferenceOfRegister(frame, expression_reg,
1500                                                  expression_offset)) {
1501       if ((reg == ConstString(expression_reg->name) ||
1502            reg == ConstString(expression_reg->alt_name)) &&
1503           expression_offset == offset) {
1504         return frame.GetValueObjectForFrameVariable(var_sp, eNoDynamicValues);
1505       }
1506     }
1507   }
1508 
1509   bool is_in_return_register = false;
1510   ABISP abi_sp = frame.CalculateProcess()->GetABI();
1511   RegisterInfo return_register_info;
1512 
1513   if (abi_sp) {
1514     const char *return_register_name;
1515     const RegisterInfo *reg_info = nullptr;
1516     if (abi_sp->GetPointerReturnRegister(return_register_name) &&
1517         reg == ConstString(return_register_name) &&
1518         (reg_info = frame.GetRegisterContext()->GetRegisterInfoByName(
1519              return_register_name))) {
1520       is_in_return_register = true;
1521       return_register_info = *reg_info;
1522     }
1523   }
1524 
1525   const uint32_t current_inst =
1526       disassembler.GetInstructionList().GetIndexOfInstructionAtAddress(pc);
1527   if (current_inst == UINT32_MAX) {
1528     return ValueObjectSP();
1529   }
1530 
1531   ValueObjectSP source_path;
1532 
1533   for (uint32_t ii = current_inst - 1; ii != (uint32_t)-1; --ii) {
1534     // This is not an exact algorithm, and it sacrifices accuracy for
1535     // generality.
1536     // Recognizing "mov" and "ld" instructions –– and which are their source and
1537     // destination operands -- is something the disassembler should do for us.
1538     InstructionSP instruction_sp =
1539         disassembler.GetInstructionList().GetInstructionAtIndex(ii);
1540 
1541     if (is_in_return_register && instruction_sp->IsCall()) {
1542       llvm::SmallVector<Instruction::Operand, 1> operands;
1543       if (!instruction_sp->ParseOperands(operands) || operands.size() != 1) {
1544         continue;
1545       }
1546 
1547       switch (operands[0].m_type) {
1548       default:
1549         break;
1550       case Instruction::Operand::Type::Immediate: {
1551         SymbolContext sc;
1552         Address load_address;
1553         if (!frame.CalculateTarget()->ResolveLoadAddress(
1554                 operands[0].m_immediate, load_address)) {
1555           break;
1556         }
1557         frame.CalculateTarget()->GetImages().ResolveSymbolContextForAddress(
1558             load_address, eSymbolContextFunction, sc);
1559         if (!sc.function) {
1560           break;
1561         }
1562         CompilerType function_type = sc.function->GetCompilerType();
1563         if (!function_type.IsFunctionType()) {
1564           break;
1565         }
1566         CompilerType return_type = function_type.GetFunctionReturnType();
1567         RegisterValue return_value;
1568         if (!frame.GetRegisterContext()->ReadRegister(&return_register_info,
1569                                                       return_value)) {
1570           break;
1571         }
1572         std::string name_str(
1573             sc.function->GetName().AsCString("<unknown function>"));
1574         name_str.append("()");
1575         Address return_value_address(return_value.GetAsUInt64());
1576         ValueObjectSP return_value_sp = ValueObjectMemory::Create(
1577             &frame, name_str.c_str(), return_value_address, return_type);
1578         return GetValueForDereferincingOffset(frame, return_value_sp, offset);
1579       }
1580       }
1581 
1582       continue;
1583     }
1584 
1585     llvm::SmallVector<Instruction::Operand, 2> operands;
1586     if (!instruction_sp->ParseOperands(operands) || operands.size() != 2) {
1587       continue;
1588     }
1589 
1590     Instruction::Operand *register_operand = nullptr;
1591     Instruction::Operand *origin_operand = nullptr;
1592     if (operands[0].m_type == Instruction::Operand::Type::Register &&
1593         operands[0].m_clobbered == true && operands[0].m_register == reg) {
1594       register_operand = &operands[0];
1595       origin_operand = &operands[1];
1596     } else if (operands[1].m_type == Instruction::Operand::Type::Register &&
1597                operands[1].m_clobbered == true &&
1598                operands[1].m_register == reg) {
1599       register_operand = &operands[1];
1600       origin_operand = &operands[0];
1601     } else {
1602       continue;
1603     }
1604 
1605     // We have an origin operand.  Can we track its value down?
1606     switch (origin_operand->m_type) {
1607     default:
1608       break;
1609     case Instruction::Operand::Type::Register:
1610       source_path =
1611           DoGuessValueAt(frame, origin_operand->m_register, 0, disassembler,
1612                          variables, instruction_sp->GetAddress());
1613       break;
1614     case Instruction::Operand::Type::Dereference: {
1615       const Instruction::Operand &pointer = origin_operand->m_children[0];
1616       switch (pointer.m_type) {
1617       default:
1618         break;
1619       case Instruction::Operand::Type::Register:
1620         source_path = DoGuessValueAt(frame, pointer.m_register, 0, disassembler,
1621                                      variables, instruction_sp->GetAddress());
1622         if (source_path) {
1623           Error err;
1624           source_path = source_path->Dereference(err);
1625           if (!err.Success()) {
1626             source_path.reset();
1627           }
1628         }
1629         break;
1630       case Instruction::Operand::Type::Sum: {
1631         const Instruction::Operand *origin_register = nullptr;
1632         const Instruction::Operand *origin_offset = nullptr;
1633         if (pointer.m_children.size() != 2) {
1634           break;
1635         }
1636         if (pointer.m_children[0].m_type ==
1637                 Instruction::Operand::Type::Register &&
1638             pointer.m_children[1].m_type ==
1639                 Instruction::Operand::Type::Immediate) {
1640           origin_register = &pointer.m_children[0];
1641           origin_offset = &pointer.m_children[1];
1642         } else if (pointer.m_children[1].m_type ==
1643                        Instruction::Operand::Type::Register &&
1644                    pointer.m_children[0].m_type ==
1645                        Instruction::Operand::Type::Immediate) {
1646           origin_register = &pointer.m_children[1];
1647           origin_offset = &pointer.m_children[0];
1648         }
1649         if (!origin_register) {
1650           break;
1651         }
1652         int64_t signed_origin_offset =
1653             origin_offset->m_negative ? -((int64_t)origin_offset->m_immediate)
1654                                       : origin_offset->m_immediate;
1655         source_path = DoGuessValueAt(frame, origin_register->m_register,
1656                                      signed_origin_offset, disassembler,
1657                                      variables, instruction_sp->GetAddress());
1658         if (!source_path) {
1659           break;
1660         }
1661         source_path =
1662             GetValueForDereferincingOffset(frame, source_path, offset);
1663         break;
1664       }
1665       }
1666     }
1667     }
1668 
1669     if (source_path) {
1670       return source_path;
1671     }
1672   }
1673 
1674   return ValueObjectSP();
1675 }
1676 }
1677 
1678 lldb::ValueObjectSP StackFrame::GuessValueForRegisterAndOffset(ConstString reg,
1679                                                                int64_t offset) {
1680   TargetSP target_sp = CalculateTarget();
1681 
1682   const ArchSpec &target_arch = target_sp->GetArchitecture();
1683 
1684   Block *frame_block = GetFrameBlock();
1685 
1686   if (!frame_block) {
1687     return ValueObjectSP();
1688   }
1689 
1690   Function *function = frame_block->CalculateSymbolContextFunction();
1691   if (!function) {
1692     return ValueObjectSP();
1693   }
1694 
1695   AddressRange pc_range = function->GetAddressRange();
1696 
1697   if (GetFrameCodeAddress().GetFileAddress() <
1698           pc_range.GetBaseAddress().GetFileAddress() ||
1699       GetFrameCodeAddress().GetFileAddress() -
1700               pc_range.GetBaseAddress().GetFileAddress() >=
1701           pc_range.GetByteSize()) {
1702     return ValueObjectSP();
1703   }
1704 
1705   ExecutionContext exe_ctx(shared_from_this());
1706 
1707   const char *plugin_name = nullptr;
1708   const char *flavor = nullptr;
1709   const bool prefer_file_cache = false;
1710   DisassemblerSP disassembler_sp = Disassembler::DisassembleRange(
1711       target_arch, plugin_name, flavor, exe_ctx, pc_range, prefer_file_cache);
1712 
1713   if (!disassembler_sp || !disassembler_sp->GetInstructionList().GetSize()) {
1714     return ValueObjectSP();
1715   }
1716 
1717   const bool get_file_globals = false;
1718   VariableList *variables = GetVariableList(get_file_globals);
1719 
1720   if (!variables) {
1721     return ValueObjectSP();
1722   }
1723 
1724   return DoGuessValueAt(*this, reg, offset, *disassembler_sp, *variables,
1725                         GetFrameCodeAddress());
1726 }
1727 
1728 TargetSP StackFrame::CalculateTarget() {
1729   TargetSP target_sp;
1730   ThreadSP thread_sp(GetThread());
1731   if (thread_sp) {
1732     ProcessSP process_sp(thread_sp->CalculateProcess());
1733     if (process_sp)
1734       target_sp = process_sp->CalculateTarget();
1735   }
1736   return target_sp;
1737 }
1738 
1739 ProcessSP StackFrame::CalculateProcess() {
1740   ProcessSP process_sp;
1741   ThreadSP thread_sp(GetThread());
1742   if (thread_sp)
1743     process_sp = thread_sp->CalculateProcess();
1744   return process_sp;
1745 }
1746 
1747 ThreadSP StackFrame::CalculateThread() { return GetThread(); }
1748 
1749 StackFrameSP StackFrame::CalculateStackFrame() { return shared_from_this(); }
1750 
1751 void StackFrame::CalculateExecutionContext(ExecutionContext &exe_ctx) {
1752   exe_ctx.SetContext(shared_from_this());
1753 }
1754 
1755 void StackFrame::DumpUsingSettingsFormat(Stream *strm,
1756                                          const char *frame_marker) {
1757   if (strm == nullptr)
1758     return;
1759 
1760   GetSymbolContext(eSymbolContextEverything);
1761   ExecutionContext exe_ctx(shared_from_this());
1762   StreamString s;
1763 
1764   if (frame_marker)
1765     s.PutCString(frame_marker);
1766 
1767   const FormatEntity::Entry *frame_format = nullptr;
1768   Target *target = exe_ctx.GetTargetPtr();
1769   if (target)
1770     frame_format = target->GetDebugger().GetFrameFormat();
1771   if (frame_format && FormatEntity::Format(*frame_format, s, &m_sc, &exe_ctx,
1772                                            nullptr, nullptr, false, false)) {
1773     strm->Write(s.GetData(), s.GetSize());
1774   } else {
1775     Dump(strm, true, false);
1776     strm->EOL();
1777   }
1778 }
1779 
1780 void StackFrame::Dump(Stream *strm, bool show_frame_index,
1781                       bool show_fullpaths) {
1782   if (strm == nullptr)
1783     return;
1784 
1785   if (show_frame_index)
1786     strm->Printf("frame #%u: ", m_frame_index);
1787   ExecutionContext exe_ctx(shared_from_this());
1788   Target *target = exe_ctx.GetTargetPtr();
1789   strm->Printf("0x%0*" PRIx64 " ",
1790                target ? (target->GetArchitecture().GetAddressByteSize() * 2)
1791                       : 16,
1792                GetFrameCodeAddress().GetLoadAddress(target));
1793   GetSymbolContext(eSymbolContextEverything);
1794   const bool show_module = true;
1795   const bool show_inline = true;
1796   const bool show_function_arguments = true;
1797   const bool show_function_name = true;
1798   m_sc.DumpStopContext(strm, exe_ctx.GetBestExecutionContextScope(),
1799                        GetFrameCodeAddress(), show_fullpaths, show_module,
1800                        show_inline, show_function_arguments,
1801                        show_function_name);
1802 }
1803 
1804 void StackFrame::UpdateCurrentFrameFromPreviousFrame(StackFrame &prev_frame) {
1805   std::lock_guard<std::recursive_mutex> guard(m_mutex);
1806   assert(GetStackID() ==
1807          prev_frame.GetStackID()); // TODO: remove this after some testing
1808   m_variable_list_sp = prev_frame.m_variable_list_sp;
1809   m_variable_list_value_objects.Swap(prev_frame.m_variable_list_value_objects);
1810   if (!m_disassembly.GetString().empty())
1811     m_disassembly.GetString().swap(m_disassembly.GetString());
1812 }
1813 
1814 void StackFrame::UpdatePreviousFrameFromCurrentFrame(StackFrame &curr_frame) {
1815   std::lock_guard<std::recursive_mutex> guard(m_mutex);
1816   assert(GetStackID() ==
1817          curr_frame.GetStackID());     // TODO: remove this after some testing
1818   m_id.SetPC(curr_frame.m_id.GetPC()); // Update the Stack ID PC value
1819   assert(GetThread() == curr_frame.GetThread());
1820   m_frame_index = curr_frame.m_frame_index;
1821   m_concrete_frame_index = curr_frame.m_concrete_frame_index;
1822   m_reg_context_sp = curr_frame.m_reg_context_sp;
1823   m_frame_code_addr = curr_frame.m_frame_code_addr;
1824   assert(!m_sc.target_sp || !curr_frame.m_sc.target_sp ||
1825          m_sc.target_sp.get() == curr_frame.m_sc.target_sp.get());
1826   assert(!m_sc.module_sp || !curr_frame.m_sc.module_sp ||
1827          m_sc.module_sp.get() == curr_frame.m_sc.module_sp.get());
1828   assert(m_sc.comp_unit == nullptr || curr_frame.m_sc.comp_unit == nullptr ||
1829          m_sc.comp_unit == curr_frame.m_sc.comp_unit);
1830   assert(m_sc.function == nullptr || curr_frame.m_sc.function == nullptr ||
1831          m_sc.function == curr_frame.m_sc.function);
1832   m_sc = curr_frame.m_sc;
1833   m_flags.Clear(GOT_FRAME_BASE | eSymbolContextEverything);
1834   m_flags.Set(m_sc.GetResolvedMask());
1835   m_frame_base.Clear();
1836   m_frame_base_error.Clear();
1837 }
1838 
1839 bool StackFrame::HasCachedData() const {
1840   if (m_variable_list_sp)
1841     return true;
1842   if (m_variable_list_value_objects.GetSize() > 0)
1843     return true;
1844   if (!m_disassembly.GetString().empty())
1845     return true;
1846   return false;
1847 }
1848 
1849 bool StackFrame::GetStatus(Stream &strm, bool show_frame_info, bool show_source,
1850                            const char *frame_marker) {
1851 
1852   if (show_frame_info) {
1853     strm.Indent();
1854     DumpUsingSettingsFormat(&strm, frame_marker);
1855   }
1856 
1857   if (show_source) {
1858     ExecutionContext exe_ctx(shared_from_this());
1859     bool have_source = false, have_debuginfo = false;
1860     Debugger::StopDisassemblyType disasm_display =
1861         Debugger::eStopDisassemblyTypeNever;
1862     Target *target = exe_ctx.GetTargetPtr();
1863     if (target) {
1864       Debugger &debugger = target->GetDebugger();
1865       const uint32_t source_lines_before =
1866           debugger.GetStopSourceLineCount(true);
1867       const uint32_t source_lines_after =
1868           debugger.GetStopSourceLineCount(false);
1869       disasm_display = debugger.GetStopDisassemblyDisplay();
1870 
1871       GetSymbolContext(eSymbolContextCompUnit | eSymbolContextLineEntry);
1872       if (m_sc.comp_unit && m_sc.line_entry.IsValid()) {
1873         have_debuginfo = true;
1874         if (source_lines_before > 0 || source_lines_after > 0) {
1875           size_t num_lines =
1876               target->GetSourceManager().DisplaySourceLinesWithLineNumbers(
1877                   m_sc.line_entry.file, m_sc.line_entry.line,
1878                   source_lines_before, source_lines_after, "->", &strm);
1879           if (num_lines != 0)
1880             have_source = true;
1881           // TODO: Give here a one time warning if source file is missing.
1882         }
1883       }
1884       switch (disasm_display) {
1885       case Debugger::eStopDisassemblyTypeNever:
1886         break;
1887 
1888       case Debugger::eStopDisassemblyTypeNoDebugInfo:
1889         if (have_debuginfo)
1890           break;
1891         LLVM_FALLTHROUGH;
1892 
1893       case Debugger::eStopDisassemblyTypeNoSource:
1894         if (have_source)
1895           break;
1896         LLVM_FALLTHROUGH;
1897 
1898       case Debugger::eStopDisassemblyTypeAlways:
1899         if (target) {
1900           const uint32_t disasm_lines = debugger.GetDisassemblyLineCount();
1901           if (disasm_lines > 0) {
1902             const ArchSpec &target_arch = target->GetArchitecture();
1903             AddressRange pc_range;
1904             pc_range.GetBaseAddress() = GetFrameCodeAddress();
1905             pc_range.SetByteSize(disasm_lines *
1906                                  target_arch.GetMaximumOpcodeByteSize());
1907             const char *plugin_name = nullptr;
1908             const char *flavor = nullptr;
1909             Disassembler::Disassemble(target->GetDebugger(), target_arch,
1910                                       plugin_name, flavor, exe_ctx, pc_range,
1911                                       disasm_lines, 0,
1912                                       Disassembler::eOptionMarkPCAddress, strm);
1913           }
1914         }
1915         break;
1916       }
1917     }
1918   }
1919   return true;
1920 }
1921