1 //===-- ItaniumABILanguageRuntime.cpp --------------------------------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "ItaniumABILanguageRuntime.h"
11
12 #include "lldb/Breakpoint/BreakpointLocation.h"
13 #include "lldb/Core/ConstString.h"
14 #include "lldb/Core/Error.h"
15 #include "lldb/Core/Log.h"
16 #include "lldb/Core/Module.h"
17 #include "lldb/Core/PluginManager.h"
18 #include "lldb/Core/Scalar.h"
19 #include "lldb/Core/ValueObject.h"
20 #include "lldb/Core/ValueObjectMemory.h"
21 #include "lldb/Symbol/ClangASTContext.h"
22 #include "lldb/Symbol/Symbol.h"
23 #include "lldb/Symbol/TypeList.h"
24 #include "lldb/Target/Process.h"
25 #include "lldb/Target/RegisterContext.h"
26 #include "lldb/Target/StopInfo.h"
27 #include "lldb/Target/Target.h"
28 #include "lldb/Target/Thread.h"
29
30 #include <vector>
31
32 using namespace lldb;
33 using namespace lldb_private;
34
35 static const char *vtable_demangled_prefix = "vtable for ";
36
37 bool
CouldHaveDynamicValue(ValueObject & in_value)38 ItaniumABILanguageRuntime::CouldHaveDynamicValue (ValueObject &in_value)
39 {
40 const bool check_cxx = true;
41 const bool check_objc = false;
42 return in_value.GetClangType().IsPossibleDynamicType (NULL, check_cxx, check_objc);
43 }
44
45 bool
GetDynamicTypeAndAddress(ValueObject & in_value,lldb::DynamicValueType use_dynamic,TypeAndOrName & class_type_or_name,Address & dynamic_address)46 ItaniumABILanguageRuntime::GetDynamicTypeAndAddress (ValueObject &in_value,
47 lldb::DynamicValueType use_dynamic,
48 TypeAndOrName &class_type_or_name,
49 Address &dynamic_address)
50 {
51 // For Itanium, if the type has a vtable pointer in the object, it will be at offset 0
52 // in the object. That will point to the "address point" within the vtable (not the beginning of the
53 // vtable.) We can then look up the symbol containing this "address point" and that symbol's name
54 // demangled will contain the full class name.
55 // The second pointer above the "address point" is the "offset_to_top". We'll use that to get the
56 // start of the value object which holds the dynamic type.
57 //
58
59 class_type_or_name.Clear();
60
61 // Only a pointer or reference type can have a different dynamic and static type:
62 if (CouldHaveDynamicValue (in_value))
63 {
64 // First job, pull out the address at 0 offset from the object.
65 AddressType address_type;
66 lldb::addr_t original_ptr = in_value.GetPointerValue(&address_type);
67 if (original_ptr == LLDB_INVALID_ADDRESS)
68 return false;
69
70 ExecutionContext exe_ctx (in_value.GetExecutionContextRef());
71
72 Target *target = exe_ctx.GetTargetPtr();
73 Process *process = exe_ctx.GetProcessPtr();
74
75 char memory_buffer[16];
76 DataExtractor data(memory_buffer, sizeof(memory_buffer),
77 process->GetByteOrder(),
78 process->GetAddressByteSize());
79 size_t address_byte_size = process->GetAddressByteSize();
80 Error error;
81 size_t bytes_read = process->ReadMemory (original_ptr,
82 memory_buffer,
83 address_byte_size,
84 error);
85 if (!error.Success() || (bytes_read != address_byte_size))
86 {
87 return false;
88 }
89
90 lldb::offset_t offset = 0;
91 lldb::addr_t vtable_address_point = data.GetAddress (&offset);
92
93 if (offset == 0)
94 return false;
95
96 // Now find the symbol that contains this address:
97
98 SymbolContext sc;
99 Address address_point_address;
100 if (target && !target->GetSectionLoadList().IsEmpty())
101 {
102 if (target->GetSectionLoadList().ResolveLoadAddress (vtable_address_point, address_point_address))
103 {
104 target->GetImages().ResolveSymbolContextForAddress (address_point_address, eSymbolContextSymbol, sc);
105 Symbol *symbol = sc.symbol;
106 if (symbol != NULL)
107 {
108 const char *name = symbol->GetMangled().GetDemangledName().AsCString();
109 if (strstr(name, vtable_demangled_prefix) == name)
110 {
111 Log *log (lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT));
112 if (log)
113 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has vtable symbol '%s'\n",
114 original_ptr,
115 in_value.GetTypeName().GetCString(),
116 name);
117 // We are a C++ class, that's good. Get the class name and look it up:
118 const char *class_name = name + strlen(vtable_demangled_prefix);
119 class_type_or_name.SetName (class_name);
120 const bool exact_match = true;
121 TypeList class_types;
122
123 uint32_t num_matches = 0;
124 // First look in the module that the vtable symbol came from
125 // and look for a single exact match.
126 if (sc.module_sp)
127 {
128 num_matches = sc.module_sp->FindTypes (sc,
129 ConstString(class_name),
130 exact_match,
131 1,
132 class_types);
133 }
134
135 // If we didn't find a symbol, then move on to the entire
136 // module list in the target and get as many unique matches
137 // as possible
138 if (num_matches == 0)
139 {
140 num_matches = target->GetImages().FindTypes (sc,
141 ConstString(class_name),
142 exact_match,
143 UINT32_MAX,
144 class_types);
145 }
146
147 lldb::TypeSP type_sp;
148 if (num_matches == 0)
149 {
150 if (log)
151 log->Printf("0x%16.16" PRIx64 ": is not dynamic\n", original_ptr);
152 return false;
153 }
154 if (num_matches == 1)
155 {
156 type_sp = class_types.GetTypeAtIndex(0);
157 if (log)
158 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has dynamic type: uid={0x%" PRIx64 "}, type-name='%s'\n",
159 original_ptr,
160 in_value.GetTypeName().AsCString(),
161 type_sp->GetID(),
162 type_sp->GetName().GetCString());
163
164 class_type_or_name.SetTypeSP(class_types.GetTypeAtIndex(0));
165 }
166 else if (num_matches > 1)
167 {
168 size_t i;
169 if (log)
170 {
171 for (i = 0; i < num_matches; i++)
172 {
173 type_sp = class_types.GetTypeAtIndex(i);
174 if (type_sp)
175 {
176 if (log)
177 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has multiple matching dynamic types: uid={0x%" PRIx64 "}, type-name='%s'\n",
178 original_ptr,
179 in_value.GetTypeName().AsCString(),
180 type_sp->GetID(),
181 type_sp->GetName().GetCString());
182 }
183 }
184 }
185
186 for (i = 0; i < num_matches; i++)
187 {
188 type_sp = class_types.GetTypeAtIndex(i);
189 if (type_sp)
190 {
191 if (type_sp->GetClangFullType().IsCXXClassType())
192 {
193 if (log)
194 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has multiple matching dynamic types, picking this one: uid={0x%" PRIx64 "}, type-name='%s'\n",
195 original_ptr,
196 in_value.GetTypeName().AsCString(),
197 type_sp->GetID(),
198 type_sp->GetName().GetCString());
199 class_type_or_name.SetTypeSP(type_sp);
200 break;
201 }
202 }
203 }
204
205 if (i == num_matches)
206 {
207 if (log)
208 log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has multiple matching dynamic types, didn't find a C++ match\n",
209 original_ptr,
210 in_value.GetTypeName().AsCString());
211 return false;
212 }
213 }
214
215 // There can only be one type with a given name,
216 // so we've just found duplicate definitions, and this
217 // one will do as well as any other.
218 // We don't consider something to have a dynamic type if
219 // it is the same as the static type. So compare against
220 // the value we were handed.
221 if (type_sp)
222 {
223 if (ClangASTContext::AreTypesSame (in_value.GetClangType(),
224 type_sp->GetClangFullType()))
225 {
226 // The dynamic type we found was the same type,
227 // so we don't have a dynamic type here...
228 return false;
229 }
230
231 // The offset_to_top is two pointers above the address.
232 Address offset_to_top_address = address_point_address;
233 int64_t slide = -2 * ((int64_t) target->GetArchitecture().GetAddressByteSize());
234 offset_to_top_address.Slide (slide);
235
236 Error error;
237 lldb::addr_t offset_to_top_location = offset_to_top_address.GetLoadAddress(target);
238
239 size_t bytes_read = process->ReadMemory (offset_to_top_location,
240 memory_buffer,
241 address_byte_size,
242 error);
243
244 if (!error.Success() || (bytes_read != address_byte_size))
245 {
246 return false;
247 }
248
249 offset = 0;
250 int64_t offset_to_top = data.GetMaxS64(&offset, process->GetAddressByteSize());
251
252 // So the dynamic type is a value that starts at offset_to_top
253 // above the original address.
254 lldb::addr_t dynamic_addr = original_ptr + offset_to_top;
255 if (!target->GetSectionLoadList().ResolveLoadAddress (dynamic_addr, dynamic_address))
256 {
257 dynamic_address.SetRawAddress(dynamic_addr);
258 }
259 return true;
260 }
261 }
262 }
263 }
264 }
265 }
266
267 return class_type_or_name.IsEmpty() == false;
268 }
269
270 bool
IsVTableName(const char * name)271 ItaniumABILanguageRuntime::IsVTableName (const char *name)
272 {
273 if (name == NULL)
274 return false;
275
276 // Can we maybe ask Clang about this?
277 if (strstr (name, "_vptr$") == name)
278 return true;
279 else
280 return false;
281 }
282
283 //------------------------------------------------------------------
284 // Static Functions
285 //------------------------------------------------------------------
286 LanguageRuntime *
CreateInstance(Process * process,lldb::LanguageType language)287 ItaniumABILanguageRuntime::CreateInstance (Process *process, lldb::LanguageType language)
288 {
289 // FIXME: We have to check the process and make sure we actually know that this process supports
290 // the Itanium ABI.
291 if (language == eLanguageTypeC_plus_plus)
292 return new ItaniumABILanguageRuntime (process);
293 else
294 return NULL;
295 }
296
297 void
Initialize()298 ItaniumABILanguageRuntime::Initialize()
299 {
300 PluginManager::RegisterPlugin (GetPluginNameStatic(),
301 "Itanium ABI for the C++ language",
302 CreateInstance);
303 }
304
305 void
Terminate()306 ItaniumABILanguageRuntime::Terminate()
307 {
308 PluginManager::UnregisterPlugin (CreateInstance);
309 }
310
311 lldb_private::ConstString
GetPluginNameStatic()312 ItaniumABILanguageRuntime::GetPluginNameStatic()
313 {
314 static ConstString g_name("itanium");
315 return g_name;
316 }
317
318 //------------------------------------------------------------------
319 // PluginInterface protocol
320 //------------------------------------------------------------------
321 lldb_private::ConstString
GetPluginName()322 ItaniumABILanguageRuntime::GetPluginName()
323 {
324 return GetPluginNameStatic();
325 }
326
327 uint32_t
GetPluginVersion()328 ItaniumABILanguageRuntime::GetPluginVersion()
329 {
330 return 1;
331 }
332
333 BreakpointResolverSP
CreateExceptionResolver(Breakpoint * bkpt,bool catch_bp,bool throw_bp)334 ItaniumABILanguageRuntime::CreateExceptionResolver (Breakpoint *bkpt, bool catch_bp, bool throw_bp)
335 {
336 return CreateExceptionResolver (bkpt, catch_bp, throw_bp, false);
337 }
338
339 BreakpointResolverSP
CreateExceptionResolver(Breakpoint * bkpt,bool catch_bp,bool throw_bp,bool for_expressions)340 ItaniumABILanguageRuntime::CreateExceptionResolver (Breakpoint *bkpt, bool catch_bp, bool throw_bp, bool for_expressions)
341 {
342 // One complication here is that most users DON'T want to stop at __cxa_allocate_expression, but until we can do
343 // anything better with predicting unwinding the expression parser does. So we have two forms of the exception
344 // breakpoints, one for expressions that leaves out __cxa_allocate_exception, and one that includes it.
345 // The SetExceptionBreakpoints does the latter, the CreateExceptionBreakpoint in the runtime the former.
346 static const char *g_catch_name = "__cxa_begin_catch";
347 static const char *g_throw_name1 = "__cxa_throw";
348 static const char *g_throw_name2 = "__cxa_rethrow";
349 static const char *g_exception_throw_name = "__cxa_allocate_exception";
350 std::vector<const char *> exception_names;
351 exception_names.reserve(4);
352 if (catch_bp)
353 exception_names.push_back(g_catch_name);
354
355 if (throw_bp)
356 {
357 exception_names.push_back(g_throw_name1);
358 exception_names.push_back(g_throw_name2);
359 }
360
361 if (for_expressions)
362 exception_names.push_back(g_exception_throw_name);
363
364 BreakpointResolverSP resolver_sp (new BreakpointResolverName (bkpt,
365 exception_names.data(),
366 exception_names.size(),
367 eFunctionNameTypeBase,
368 eLazyBoolNo));
369
370 return resolver_sp;
371 }
372
373
374
375 lldb::SearchFilterSP
CreateExceptionSearchFilter()376 ItaniumABILanguageRuntime::CreateExceptionSearchFilter ()
377 {
378 Target &target = m_process->GetTarget();
379
380 if (target.GetArchitecture().GetTriple().getVendor() == llvm::Triple::Apple)
381 {
382 // Limit the number of modules that are searched for these breakpoints for
383 // Apple binaries.
384 FileSpecList filter_modules;
385 filter_modules.Append(FileSpec("libc++abi.dylib", false));
386 filter_modules.Append(FileSpec("libSystem.B.dylib", false));
387 return target.GetSearchFilterForModuleList(&filter_modules);
388 }
389 else
390 {
391 return LanguageRuntime::CreateExceptionSearchFilter();
392 }
393 }
394
395 lldb::BreakpointSP
CreateExceptionBreakpoint(bool catch_bp,bool throw_bp,bool for_expressions,bool is_internal)396 ItaniumABILanguageRuntime::CreateExceptionBreakpoint (bool catch_bp,
397 bool throw_bp,
398 bool for_expressions,
399 bool is_internal)
400 {
401 Target &target = m_process->GetTarget();
402 FileSpecList filter_modules;
403 BreakpointResolverSP exception_resolver_sp = CreateExceptionResolver (NULL, catch_bp, throw_bp, for_expressions);
404 SearchFilterSP filter_sp (CreateExceptionSearchFilter ());
405 return target.CreateBreakpoint (filter_sp, exception_resolver_sp, is_internal);
406 }
407
408 void
SetExceptionBreakpoints()409 ItaniumABILanguageRuntime::SetExceptionBreakpoints ()
410 {
411 if (!m_process)
412 return;
413
414 const bool catch_bp = false;
415 const bool throw_bp = true;
416 const bool is_internal = true;
417 const bool for_expressions = true;
418
419 // For the exception breakpoints set by the Expression parser, we'll be a little more aggressive and
420 // stop at exception allocation as well.
421
422 if (m_cxx_exception_bp_sp)
423 {
424 m_cxx_exception_bp_sp->SetEnabled (true);
425 }
426 else
427 {
428 m_cxx_exception_bp_sp = CreateExceptionBreakpoint (catch_bp, throw_bp, for_expressions, is_internal);
429 if (m_cxx_exception_bp_sp)
430 m_cxx_exception_bp_sp->SetBreakpointKind("c++ exception");
431 }
432
433 }
434
435 void
ClearExceptionBreakpoints()436 ItaniumABILanguageRuntime::ClearExceptionBreakpoints ()
437 {
438 if (!m_process)
439 return;
440
441 if (m_cxx_exception_bp_sp)
442 {
443 m_cxx_exception_bp_sp->SetEnabled (false);
444 }
445 }
446
447 bool
ExceptionBreakpointsExplainStop(lldb::StopInfoSP stop_reason)448 ItaniumABILanguageRuntime::ExceptionBreakpointsExplainStop (lldb::StopInfoSP stop_reason)
449 {
450 if (!m_process)
451 return false;
452
453 if (!stop_reason ||
454 stop_reason->GetStopReason() != eStopReasonBreakpoint)
455 return false;
456
457 uint64_t break_site_id = stop_reason->GetValue();
458 return m_process->GetBreakpointSiteList().BreakpointSiteContainsBreakpoint(break_site_id,
459 m_cxx_exception_bp_sp->GetID());
460
461 }
462