1 //===-- ValueObjectVariable.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
11 #include "lldb/Core/ValueObjectVariable.h"
12
13 // C Includes
14 // C++ Includes
15 // Other libraries and framework includes
16 // Project includes
17 #include "lldb/Core/Module.h"
18 #include "lldb/Core/RegisterValue.h"
19 #include "lldb/Core/ValueObjectList.h"
20 #include "lldb/Core/Value.h"
21
22 #include "lldb/Symbol/Function.h"
23 #include "lldb/Symbol/ObjectFile.h"
24 #include "lldb/Symbol/SymbolContext.h"
25 #include "lldb/Symbol/SymbolContextScope.h"
26 #include "lldb/Symbol/Type.h"
27 #include "lldb/Symbol/Variable.h"
28
29 #include "lldb/Target/ExecutionContext.h"
30 #include "lldb/Target/Process.h"
31 #include "lldb/Target/RegisterContext.h"
32 #include "lldb/Target/Target.h"
33 #include "lldb/Target/Thread.h"
34
35
36 using namespace lldb_private;
37
38 lldb::ValueObjectSP
Create(ExecutionContextScope * exe_scope,const lldb::VariableSP & var_sp)39 ValueObjectVariable::Create (ExecutionContextScope *exe_scope, const lldb::VariableSP &var_sp)
40 {
41 return (new ValueObjectVariable (exe_scope, var_sp))->GetSP();
42 }
43
ValueObjectVariable(ExecutionContextScope * exe_scope,const lldb::VariableSP & var_sp)44 ValueObjectVariable::ValueObjectVariable (ExecutionContextScope *exe_scope, const lldb::VariableSP &var_sp) :
45 ValueObject(exe_scope),
46 m_variable_sp(var_sp)
47 {
48 // Do not attempt to construct one of these objects with no variable!
49 assert (m_variable_sp.get() != NULL);
50 m_name = var_sp->GetName();
51 }
52
~ValueObjectVariable()53 ValueObjectVariable::~ValueObjectVariable()
54 {
55 }
56
57 ClangASTType
GetClangTypeImpl()58 ValueObjectVariable::GetClangTypeImpl ()
59 {
60 Type *var_type = m_variable_sp->GetType();
61 if (var_type)
62 return var_type->GetClangForwardType();
63 return ClangASTType();
64 }
65
66 ConstString
GetTypeName()67 ValueObjectVariable::GetTypeName()
68 {
69 Type * var_type = m_variable_sp->GetType();
70 if (var_type)
71 return var_type->GetName();
72 return ConstString();
73 }
74
75 ConstString
GetDisplayTypeName()76 ValueObjectVariable::GetDisplayTypeName()
77 {
78 Type * var_type = m_variable_sp->GetType();
79 if (var_type)
80 return var_type->GetClangForwardType().GetDisplayTypeName();
81 return ConstString();
82 }
83
84 ConstString
GetQualifiedTypeName()85 ValueObjectVariable::GetQualifiedTypeName()
86 {
87 Type * var_type = m_variable_sp->GetType();
88 if (var_type)
89 return var_type->GetQualifiedName();
90 return ConstString();
91 }
92
93 size_t
CalculateNumChildren()94 ValueObjectVariable::CalculateNumChildren()
95 {
96 ClangASTType type(GetClangType());
97
98 if (!type.IsValid())
99 return 0;
100
101 const bool omit_empty_base_classes = true;
102 return type.GetNumChildren(omit_empty_base_classes);
103 }
104
105 uint64_t
GetByteSize()106 ValueObjectVariable::GetByteSize()
107 {
108 ExecutionContext exe_ctx(GetExecutionContextRef());
109
110 ClangASTType type(GetClangType());
111
112 if (!type.IsValid())
113 return 0;
114
115 return type.GetByteSize(exe_ctx.GetBestExecutionContextScope());
116 }
117
118 lldb::ValueType
GetValueType() const119 ValueObjectVariable::GetValueType() const
120 {
121 if (m_variable_sp)
122 return m_variable_sp->GetScope();
123 return lldb::eValueTypeInvalid;
124 }
125
126 bool
UpdateValue()127 ValueObjectVariable::UpdateValue ()
128 {
129 SetValueIsValid (false);
130 m_error.Clear();
131
132 Variable *variable = m_variable_sp.get();
133 DWARFExpression &expr = variable->LocationExpression();
134
135 if (variable->GetLocationIsConstantValueData())
136 {
137 // expr doesn't contain DWARF bytes, it contains the constant variable
138 // value bytes themselves...
139 if (expr.GetExpressionData(m_data))
140 m_value.SetContext(Value::eContextTypeVariable, variable);
141 else
142 m_error.SetErrorString ("empty constant data");
143 // constant bytes can't be edited - sorry
144 m_resolved_value.SetContext(Value::eContextTypeInvalid, NULL);
145 }
146 else
147 {
148 lldb::addr_t loclist_base_load_addr = LLDB_INVALID_ADDRESS;
149 ExecutionContext exe_ctx (GetExecutionContextRef());
150
151 Target *target = exe_ctx.GetTargetPtr();
152 if (target)
153 {
154 m_data.SetByteOrder(target->GetArchitecture().GetByteOrder());
155 m_data.SetAddressByteSize(target->GetArchitecture().GetAddressByteSize());
156 }
157
158 if (expr.IsLocationList())
159 {
160 SymbolContext sc;
161 variable->CalculateSymbolContext (&sc);
162 if (sc.function)
163 loclist_base_load_addr = sc.function->GetAddressRange().GetBaseAddress().GetLoadAddress (target);
164 }
165 Value old_value(m_value);
166 if (expr.Evaluate (&exe_ctx, NULL, NULL, NULL, loclist_base_load_addr, NULL, m_value, &m_error))
167 {
168 m_resolved_value = m_value;
169 m_value.SetContext(Value::eContextTypeVariable, variable);
170
171 ClangASTType clang_type = GetClangType();
172 if (clang_type.IsValid())
173 m_value.SetClangType(clang_type);
174
175 Value::ValueType value_type = m_value.GetValueType();
176
177 Process *process = exe_ctx.GetProcessPtr();
178 const bool process_is_alive = process && process->IsAlive();
179 const uint32_t type_info = clang_type.GetTypeInfo();
180 const bool is_pointer_or_ref = (type_info & (lldb::eTypeIsPointer | lldb::eTypeIsReference)) != 0;
181
182 switch (value_type)
183 {
184 case Value::eValueTypeFileAddress:
185 // If this type is a pointer, then its children will be considered load addresses
186 // if the pointer or reference is dereferenced, but only if the process is alive.
187 //
188 // There could be global variables like in the following code:
189 // struct LinkedListNode { Foo* foo; LinkedListNode* next; };
190 // Foo g_foo1;
191 // Foo g_foo2;
192 // LinkedListNode g_second_node = { &g_foo2, NULL };
193 // LinkedListNode g_first_node = { &g_foo1, &g_second_node };
194 //
195 // When we aren't running, we should be able to look at these variables using
196 // the "target variable" command. Children of the "g_first_node" always will
197 // be of the same address type as the parent. But children of the "next" member of
198 // LinkedListNode will become load addresses if we have a live process, or remain
199 // what a file address if it what a file address.
200 if (process_is_alive && is_pointer_or_ref)
201 SetAddressTypeOfChildren(eAddressTypeLoad);
202 else
203 SetAddressTypeOfChildren(eAddressTypeFile);
204 break;
205 case Value::eValueTypeHostAddress:
206 // Same as above for load addresses, except children of pointer or refs are always
207 // load addresses. Host addresses are used to store freeze dried variables. If this
208 // type is a struct, the entire struct contents will be copied into the heap of the
209 // LLDB process, but we do not currrently follow any pointers.
210 if (is_pointer_or_ref)
211 SetAddressTypeOfChildren(eAddressTypeLoad);
212 else
213 SetAddressTypeOfChildren(eAddressTypeHost);
214 break;
215 case Value::eValueTypeLoadAddress:
216 case Value::eValueTypeScalar:
217 case Value::eValueTypeVector:
218 SetAddressTypeOfChildren(eAddressTypeLoad);
219 break;
220 }
221
222 switch (value_type)
223 {
224 case Value::eValueTypeVector:
225 // fall through
226 case Value::eValueTypeScalar:
227 // The variable value is in the Scalar value inside the m_value.
228 // We can point our m_data right to it.
229 m_error = m_value.GetValueAsData (&exe_ctx, m_data, 0, GetModule().get());
230 break;
231
232 case Value::eValueTypeFileAddress:
233 case Value::eValueTypeLoadAddress:
234 case Value::eValueTypeHostAddress:
235 // The DWARF expression result was an address in the inferior
236 // process. If this variable is an aggregate type, we just need
237 // the address as the main value as all child variable objects
238 // will rely upon this location and add an offset and then read
239 // their own values as needed. If this variable is a simple
240 // type, we read all data for it into m_data.
241 // Make sure this type has a value before we try and read it
242
243 // If we have a file address, convert it to a load address if we can.
244 if (value_type == Value::eValueTypeFileAddress && process_is_alive)
245 {
246 lldb::addr_t file_addr = m_value.GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
247 if (file_addr != LLDB_INVALID_ADDRESS)
248 {
249 SymbolContext var_sc;
250 variable->CalculateSymbolContext(&var_sc);
251 if (var_sc.module_sp)
252 {
253 ObjectFile *objfile = var_sc.module_sp->GetObjectFile();
254 if (objfile)
255 {
256 Address so_addr(file_addr, objfile->GetSectionList());
257 lldb::addr_t load_addr = so_addr.GetLoadAddress (target);
258 if (load_addr != LLDB_INVALID_ADDRESS)
259 {
260 m_value.SetValueType(Value::eValueTypeLoadAddress);
261 m_value.GetScalar() = load_addr;
262 }
263 }
264 }
265 }
266 }
267
268 if (!CanProvideValue())
269 {
270 // this value object represents an aggregate type whose
271 // children have values, but this object does not. So we
272 // say we are changed if our location has changed.
273 SetValueDidChange (value_type != old_value.GetValueType() || m_value.GetScalar() != old_value.GetScalar());
274 }
275 else
276 {
277 // Copy the Value and set the context to use our Variable
278 // so it can extract read its value into m_data appropriately
279 Value value(m_value);
280 value.SetContext(Value::eContextTypeVariable, variable);
281 m_error = value.GetValueAsData(&exe_ctx, m_data, 0, GetModule().get());
282
283 SetValueDidChange (value_type != old_value.GetValueType() || m_value.GetScalar() != old_value.GetScalar());
284 }
285 break;
286 }
287
288 SetValueIsValid (m_error.Success());
289 }
290 else
291 {
292 // could not find location, won't allow editing
293 m_resolved_value.SetContext(Value::eContextTypeInvalid, NULL);
294 }
295 }
296 return m_error.Success();
297 }
298
299
300
301 bool
IsInScope()302 ValueObjectVariable::IsInScope ()
303 {
304 const ExecutionContextRef &exe_ctx_ref = GetExecutionContextRef();
305 if (exe_ctx_ref.HasFrameRef())
306 {
307 ExecutionContext exe_ctx (exe_ctx_ref);
308 StackFrame *frame = exe_ctx.GetFramePtr();
309 if (frame)
310 {
311 return m_variable_sp->IsInScope (frame);
312 }
313 else
314 {
315 // This ValueObject had a frame at one time, but now we
316 // can't locate it, so return false since we probably aren't
317 // in scope.
318 return false;
319 }
320 }
321 // We have a variable that wasn't tied to a frame, which
322 // means it is a global and is always in scope.
323 return true;
324
325 }
326
327 lldb::ModuleSP
GetModule()328 ValueObjectVariable::GetModule()
329 {
330 if (m_variable_sp)
331 {
332 SymbolContextScope *sc_scope = m_variable_sp->GetSymbolContextScope();
333 if (sc_scope)
334 {
335 return sc_scope->CalculateSymbolContextModule();
336 }
337 }
338 return lldb::ModuleSP();
339 }
340
341 SymbolContextScope *
GetSymbolContextScope()342 ValueObjectVariable::GetSymbolContextScope()
343 {
344 if (m_variable_sp)
345 return m_variable_sp->GetSymbolContextScope();
346 return NULL;
347 }
348
349 bool
GetDeclaration(Declaration & decl)350 ValueObjectVariable::GetDeclaration (Declaration &decl)
351 {
352 if (m_variable_sp)
353 {
354 decl = m_variable_sp->GetDeclaration();
355 return true;
356 }
357 return false;
358 }
359
360 const char *
GetLocationAsCString()361 ValueObjectVariable::GetLocationAsCString ()
362 {
363 if (m_resolved_value.GetContextType() == Value::eContextTypeRegisterInfo)
364 return GetLocationAsCStringImpl(m_resolved_value,
365 m_data);
366 else
367 return ValueObject::GetLocationAsCString();
368 }
369
370 bool
SetValueFromCString(const char * value_str,Error & error)371 ValueObjectVariable::SetValueFromCString (const char *value_str, Error& error)
372 {
373 if (!UpdateValueIfNeeded())
374 {
375 error.SetErrorString("unable to update value before writing");
376 return false;
377 }
378
379 if (m_resolved_value.GetContextType() == Value::eContextTypeRegisterInfo)
380 {
381 RegisterInfo *reg_info = m_resolved_value.GetRegisterInfo();
382 ExecutionContext exe_ctx(GetExecutionContextRef());
383 RegisterContext *reg_ctx = exe_ctx.GetRegisterContext();
384 RegisterValue reg_value;
385 if (!reg_info || !reg_ctx)
386 {
387 error.SetErrorString("unable to retrieve register info");
388 return false;
389 }
390 error = reg_value.SetValueFromCString(reg_info, value_str);
391 if (error.Fail())
392 return false;
393 if (reg_ctx->WriteRegister (reg_info, reg_value))
394 {
395 SetNeedsUpdate();
396 return true;
397 }
398 else
399 {
400 error.SetErrorString("unable to write back to register");
401 return false;
402 }
403 }
404 else
405 return ValueObject::SetValueFromCString(value_str, error);
406 }
407
408 bool
SetData(DataExtractor & data,Error & error)409 ValueObjectVariable::SetData (DataExtractor &data, Error &error)
410 {
411 if (!UpdateValueIfNeeded())
412 {
413 error.SetErrorString("unable to update value before writing");
414 return false;
415 }
416
417 if (m_resolved_value.GetContextType() == Value::eContextTypeRegisterInfo)
418 {
419 RegisterInfo *reg_info = m_resolved_value.GetRegisterInfo();
420 ExecutionContext exe_ctx(GetExecutionContextRef());
421 RegisterContext *reg_ctx = exe_ctx.GetRegisterContext();
422 RegisterValue reg_value;
423 if (!reg_info || !reg_ctx)
424 {
425 error.SetErrorString("unable to retrieve register info");
426 return false;
427 }
428 error = reg_value.SetValueFromData(reg_info, data, 0, true);
429 if (error.Fail())
430 return false;
431 if (reg_ctx->WriteRegister (reg_info, reg_value))
432 {
433 SetNeedsUpdate();
434 return true;
435 }
436 else
437 {
438 error.SetErrorString("unable to write back to register");
439 return false;
440 }
441 }
442 else
443 return ValueObject::SetData(data, error);
444 }
445