1 //===-- DynamicLoaderPOSIXDYLD.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 // Main header include
11 #include "DynamicLoaderPOSIXDYLD.h"
12 
13 #include "AuxVector.h"
14 
15 #include "lldb/Breakpoint/BreakpointLocation.h"
16 #include "lldb/Core/Module.h"
17 #include "lldb/Core/ModuleSpec.h"
18 #include "lldb/Core/PluginManager.h"
19 #include "lldb/Core/Section.h"
20 #include "lldb/Symbol/Function.h"
21 #include "lldb/Symbol/ObjectFile.h"
22 #include "lldb/Target/MemoryRegionInfo.h"
23 #include "lldb/Target/Platform.h"
24 #include "lldb/Target/Process.h"
25 #include "lldb/Target/Target.h"
26 #include "lldb/Target/Thread.h"
27 #include "lldb/Target/ThreadPlanRunToAddress.h"
28 #include "lldb/Utility/Log.h"
29 
30 
31 using namespace lldb;
32 using namespace lldb_private;
33 
34 void DynamicLoaderPOSIXDYLD::Initialize() {
35   PluginManager::RegisterPlugin(GetPluginNameStatic(),
36                                 GetPluginDescriptionStatic(), CreateInstance);
37 }
38 
39 void DynamicLoaderPOSIXDYLD::Terminate() {}
40 
41 lldb_private::ConstString DynamicLoaderPOSIXDYLD::GetPluginName() {
42   return GetPluginNameStatic();
43 }
44 
45 lldb_private::ConstString DynamicLoaderPOSIXDYLD::GetPluginNameStatic() {
46   static ConstString g_name("linux-dyld");
47   return g_name;
48 }
49 
50 const char *DynamicLoaderPOSIXDYLD::GetPluginDescriptionStatic() {
51   return "Dynamic loader plug-in that watches for shared library "
52          "loads/unloads in POSIX processes.";
53 }
54 
55 uint32_t DynamicLoaderPOSIXDYLD::GetPluginVersion() { return 1; }
56 
57 DynamicLoader *DynamicLoaderPOSIXDYLD::CreateInstance(Process *process,
58                                                       bool force) {
59   bool create = force;
60   if (!create) {
61     const llvm::Triple &triple_ref =
62         process->GetTarget().GetArchitecture().GetTriple();
63     if (triple_ref.getOS() == llvm::Triple::FreeBSD ||
64         triple_ref.getOS() == llvm::Triple::Linux ||
65         triple_ref.getOS() == llvm::Triple::NetBSD)
66       create = true;
67   }
68 
69   if (create)
70     return new DynamicLoaderPOSIXDYLD(process);
71   return NULL;
72 }
73 
74 DynamicLoaderPOSIXDYLD::DynamicLoaderPOSIXDYLD(Process *process)
75     : DynamicLoader(process), m_rendezvous(process),
76       m_load_offset(LLDB_INVALID_ADDRESS), m_entry_point(LLDB_INVALID_ADDRESS),
77       m_auxv(), m_dyld_bid(LLDB_INVALID_BREAK_ID),
78       m_vdso_base(LLDB_INVALID_ADDRESS),
79       m_interpreter_base(LLDB_INVALID_ADDRESS) {}
80 
81 DynamicLoaderPOSIXDYLD::~DynamicLoaderPOSIXDYLD() {
82   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
83     m_process->GetTarget().RemoveBreakpointByID(m_dyld_bid);
84     m_dyld_bid = LLDB_INVALID_BREAK_ID;
85   }
86 }
87 
88 void DynamicLoaderPOSIXDYLD::DidAttach() {
89   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
90   if (log)
91     log->Printf("DynamicLoaderPOSIXDYLD::%s() pid %" PRIu64, __FUNCTION__,
92                 m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
93 
94   m_auxv.reset(new AuxVector(m_process));
95   if (log)
96     log->Printf("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64 " reloaded auxv data",
97                 __FUNCTION__,
98                 m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
99 
100   // ask the process if it can load any of its own modules
101   m_process->LoadModules();
102 
103   ModuleSP executable_sp = GetTargetExecutable();
104   ResolveExecutableModule(executable_sp);
105 
106   // find the main process load offset
107   addr_t load_offset = ComputeLoadOffset();
108   if (log)
109     log->Printf("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
110                 " executable '%s', load_offset 0x%" PRIx64,
111                 __FUNCTION__,
112                 m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
113                 executable_sp ? executable_sp->GetFileSpec().GetPath().c_str()
114                               : "<null executable>",
115                 load_offset);
116 
117   EvalSpecialModulesStatus();
118 
119   // if we dont have a load address we cant re-base
120   bool rebase_exec = load_offset != LLDB_INVALID_ADDRESS;
121 
122   // if we have a valid executable
123   if (executable_sp.get()) {
124     lldb_private::ObjectFile *obj = executable_sp->GetObjectFile();
125     if (obj) {
126       // don't rebase if the module already has a load address
127       Target &target = m_process->GetTarget();
128       Address addr = obj->GetImageInfoAddress(&target);
129       if (addr.GetLoadAddress(&target) != LLDB_INVALID_ADDRESS)
130         rebase_exec = false;
131     }
132   } else {
133     // no executable, nothing to re-base
134     rebase_exec = false;
135   }
136 
137   // if the target executable should be re-based
138   if (rebase_exec) {
139     ModuleList module_list;
140 
141     module_list.Append(executable_sp);
142     if (log)
143       log->Printf("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
144                   " added executable '%s' to module load list",
145                   __FUNCTION__,
146                   m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
147                   executable_sp->GetFileSpec().GetPath().c_str());
148 
149     UpdateLoadedSections(executable_sp, LLDB_INVALID_ADDRESS, load_offset,
150                          true);
151 
152     LoadAllCurrentModules();
153     if (!SetRendezvousBreakpoint()) {
154       // If we cannot establish rendezvous breakpoint right now we'll try again
155       // at entry point.
156       ProbeEntry();
157     }
158 
159     m_process->GetTarget().ModulesDidLoad(module_list);
160     if (log) {
161       log->Printf("DynamicLoaderPOSIXDYLD::%s told the target about the "
162                   "modules that loaded:",
163                   __FUNCTION__);
164       for (auto module_sp : module_list.Modules()) {
165         log->Printf("-- [module] %s (pid %" PRIu64 ")",
166                     module_sp ? module_sp->GetFileSpec().GetPath().c_str()
167                               : "<null>",
168                     m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
169       }
170     }
171   }
172 }
173 
174 void DynamicLoaderPOSIXDYLD::DidLaunch() {
175   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
176   if (log)
177     log->Printf("DynamicLoaderPOSIXDYLD::%s()", __FUNCTION__);
178 
179   ModuleSP executable;
180   addr_t load_offset;
181 
182   m_auxv.reset(new AuxVector(m_process));
183 
184   executable = GetTargetExecutable();
185   load_offset = ComputeLoadOffset();
186   EvalSpecialModulesStatus();
187 
188   if (executable.get() && load_offset != LLDB_INVALID_ADDRESS) {
189     ModuleList module_list;
190     module_list.Append(executable);
191     UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset, true);
192 
193     if (log)
194       log->Printf("DynamicLoaderPOSIXDYLD::%s about to call ProbeEntry()",
195                   __FUNCTION__);
196 
197     if (!SetRendezvousBreakpoint()) {
198       // If we cannot establish rendezvous breakpoint right now we'll try again
199       // at entry point.
200       ProbeEntry();
201     }
202 
203     LoadVDSO();
204     m_process->GetTarget().ModulesDidLoad(module_list);
205   }
206 }
207 
208 Status DynamicLoaderPOSIXDYLD::CanLoadImage() { return Status(); }
209 
210 void DynamicLoaderPOSIXDYLD::UpdateLoadedSections(ModuleSP module,
211                                                   addr_t link_map_addr,
212                                                   addr_t base_addr,
213                                                   bool base_addr_is_offset) {
214   m_loaded_modules[module] = link_map_addr;
215   UpdateLoadedSectionsCommon(module, base_addr, base_addr_is_offset);
216 }
217 
218 void DynamicLoaderPOSIXDYLD::UnloadSections(const ModuleSP module) {
219   m_loaded_modules.erase(module);
220 
221   UnloadSectionsCommon(module);
222 }
223 
224 void DynamicLoaderPOSIXDYLD::ProbeEntry() {
225   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
226 
227   const addr_t entry = GetEntryPoint();
228   if (entry == LLDB_INVALID_ADDRESS) {
229     if (log)
230       log->Printf(
231           "DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
232           " GetEntryPoint() returned no address, not setting entry breakpoint",
233           __FUNCTION__,
234           m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
235     return;
236   }
237 
238   if (log)
239     log->Printf("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
240                 " GetEntryPoint() returned address 0x%" PRIx64
241                 ", setting entry breakpoint",
242                 __FUNCTION__,
243                 m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
244                 entry);
245 
246   if (m_process) {
247     Breakpoint *const entry_break =
248         m_process->GetTarget().CreateBreakpoint(entry, true, false).get();
249     entry_break->SetCallback(EntryBreakpointHit, this, true);
250     entry_break->SetBreakpointKind("shared-library-event");
251 
252     // Shoudn't hit this more than once.
253     entry_break->SetOneShot(true);
254   }
255 }
256 
257 // The runtime linker has run and initialized the rendezvous structure once the
258 // process has hit its entry point.  When we hit the corresponding breakpoint
259 // we interrogate the rendezvous structure to get the load addresses of all
260 // dependent modules for the process.  Similarly, we can discover the runtime
261 // linker function and setup a breakpoint to notify us of any dynamically
262 // loaded modules (via dlopen).
263 bool DynamicLoaderPOSIXDYLD::EntryBreakpointHit(
264     void *baton, StoppointCallbackContext *context, user_id_t break_id,
265     user_id_t break_loc_id) {
266   assert(baton && "null baton");
267   if (!baton)
268     return false;
269 
270   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
271   DynamicLoaderPOSIXDYLD *const dyld_instance =
272       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
273   if (log)
274     log->Printf("DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
275                 __FUNCTION__,
276                 dyld_instance->m_process ? dyld_instance->m_process->GetID()
277                                          : LLDB_INVALID_PROCESS_ID);
278 
279   // Disable the breakpoint --- if a stop happens right after this, which we've
280   // seen on occasion, we don't want the breakpoint stepping thread-plan logic
281   // to show a breakpoint instruction at the disassembled entry point to the
282   // program.  Disabling it prevents it.  (One-shot is not enough - one-shot
283   // removal logic only happens after the breakpoint goes public, which wasn't
284   // happening in our scenario).
285   if (dyld_instance->m_process) {
286     BreakpointSP breakpoint_sp =
287         dyld_instance->m_process->GetTarget().GetBreakpointByID(break_id);
288     if (breakpoint_sp) {
289       if (log)
290         log->Printf("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
291                     " disabling breakpoint id %" PRIu64,
292                     __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
293       breakpoint_sp->SetEnabled(false);
294     } else {
295       if (log)
296         log->Printf("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
297                     " failed to find breakpoint for breakpoint id %" PRIu64,
298                     __FUNCTION__, dyld_instance->m_process->GetID(), break_id);
299     }
300   } else {
301     if (log)
302       log->Printf("DynamicLoaderPOSIXDYLD::%s breakpoint id %" PRIu64
303                   " no Process instance!  Cannot disable breakpoint",
304                   __FUNCTION__, break_id);
305   }
306 
307   dyld_instance->LoadAllCurrentModules();
308   dyld_instance->SetRendezvousBreakpoint();
309   return false; // Continue running.
310 }
311 
312 bool DynamicLoaderPOSIXDYLD::SetRendezvousBreakpoint() {
313   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
314   if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
315     LLDB_LOG(log,
316              "Rendezvous breakpoint breakpoint id {0} for pid {1}"
317              "is already set.",
318              m_dyld_bid,
319              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
320     return true;
321   }
322 
323   addr_t break_addr;
324   Target &target = m_process->GetTarget();
325   BreakpointSP dyld_break;
326   if (m_rendezvous.IsValid()) {
327     break_addr = m_rendezvous.GetBreakAddress();
328     LLDB_LOG(log, "Setting rendezvous break address for pid {0} at {1:x}",
329              m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID,
330              break_addr);
331     dyld_break = target.CreateBreakpoint(break_addr, true, false);
332   } else {
333     LLDB_LOG(log, "Rendezvous structure is not set up yet. "
334                   "Trying to locate rendezvous breakpoint in the interpreter "
335                   "by symbol name.");
336     ModuleSP interpreter = LoadInterpreterModule();
337     if (!interpreter) {
338       LLDB_LOG(log, "Can't find interpreter, rendezvous breakpoint isn't set.");
339       return false;
340     }
341 
342     // Function names from different dynamic loaders that are known to be used
343     // as rendezvous between the loader and debuggers.
344     static std::vector<std::string> DebugStateCandidates{
345         "_dl_debug_state", "rtld_db_dlactivity", "__dl_rtld_db_dlactivity",
346         "r_debug_state",   "_r_debug_state",     "_rtld_debug_state",
347     };
348 
349     FileSpecList containingModules;
350     containingModules.Append(interpreter->GetFileSpec());
351     dyld_break = target.CreateBreakpoint(
352         &containingModules, nullptr /* containingSourceFiles */,
353         DebugStateCandidates, eFunctionNameTypeFull, eLanguageTypeC,
354         0,           /* offset */
355         eLazyBoolNo, /* skip_prologue */
356         true,        /* internal */
357         false /* request_hardware */);
358   }
359 
360   if (dyld_break->GetNumResolvedLocations() != 1) {
361     LLDB_LOG(
362         log,
363         "Rendezvous breakpoint has abnormal number of"
364         " resolved locations ({0}) in pid {1}. It's supposed to be exactly 1.",
365         dyld_break->GetNumResolvedLocations(),
366         m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
367 
368     target.RemoveBreakpointByID(dyld_break->GetID());
369     return false;
370   }
371 
372   BreakpointLocationSP location = dyld_break->GetLocationAtIndex(0);
373   LLDB_LOG(log,
374            "Successfully set rendezvous breakpoint at address {0:x} "
375            "for pid {1}",
376            location->GetLoadAddress(),
377            m_process ? m_process->GetID() : LLDB_INVALID_PROCESS_ID);
378 
379   dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
380   dyld_break->SetBreakpointKind("shared-library-event");
381   m_dyld_bid = dyld_break->GetID();
382   return true;
383 }
384 
385 bool DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(
386     void *baton, StoppointCallbackContext *context, user_id_t break_id,
387     user_id_t break_loc_id) {
388   assert(baton && "null baton");
389   if (!baton)
390     return false;
391 
392   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
393   DynamicLoaderPOSIXDYLD *const dyld_instance =
394       static_cast<DynamicLoaderPOSIXDYLD *>(baton);
395   if (log)
396     log->Printf("DynamicLoaderPOSIXDYLD::%s called for pid %" PRIu64,
397                 __FUNCTION__,
398                 dyld_instance->m_process ? dyld_instance->m_process->GetID()
399                                          : LLDB_INVALID_PROCESS_ID);
400 
401   dyld_instance->RefreshModules();
402 
403   // Return true to stop the target, false to just let the target run.
404   const bool stop_when_images_change = dyld_instance->GetStopWhenImagesChange();
405   if (log)
406     log->Printf("DynamicLoaderPOSIXDYLD::%s pid %" PRIu64
407                 " stop_when_images_change=%s",
408                 __FUNCTION__,
409                 dyld_instance->m_process ? dyld_instance->m_process->GetID()
410                                          : LLDB_INVALID_PROCESS_ID,
411                 stop_when_images_change ? "true" : "false");
412   return stop_when_images_change;
413 }
414 
415 void DynamicLoaderPOSIXDYLD::RefreshModules() {
416   if (!m_rendezvous.Resolve())
417     return;
418 
419   DYLDRendezvous::iterator I;
420   DYLDRendezvous::iterator E;
421 
422   ModuleList &loaded_modules = m_process->GetTarget().GetImages();
423 
424   if (m_rendezvous.ModulesDidLoad()) {
425     ModuleList new_modules;
426 
427     E = m_rendezvous.loaded_end();
428     for (I = m_rendezvous.loaded_begin(); I != E; ++I) {
429       ModuleSP module_sp =
430           LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
431       if (module_sp.get()) {
432         loaded_modules.AppendIfNeeded(module_sp);
433         new_modules.Append(module_sp);
434       }
435     }
436     m_process->GetTarget().ModulesDidLoad(new_modules);
437   }
438 
439   if (m_rendezvous.ModulesDidUnload()) {
440     ModuleList old_modules;
441 
442     E = m_rendezvous.unloaded_end();
443     for (I = m_rendezvous.unloaded_begin(); I != E; ++I) {
444       ModuleSpec module_spec{I->file_spec};
445       ModuleSP module_sp = loaded_modules.FindFirstModule(module_spec);
446 
447       if (module_sp.get()) {
448         old_modules.Append(module_sp);
449         UnloadSections(module_sp);
450       }
451     }
452     loaded_modules.Remove(old_modules);
453     m_process->GetTarget().ModulesDidUnload(old_modules, false);
454   }
455 }
456 
457 ThreadPlanSP
458 DynamicLoaderPOSIXDYLD::GetStepThroughTrampolinePlan(Thread &thread,
459                                                      bool stop) {
460   ThreadPlanSP thread_plan_sp;
461 
462   StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
463   const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
464   Symbol *sym = context.symbol;
465 
466   if (sym == NULL || !sym->IsTrampoline())
467     return thread_plan_sp;
468 
469   ConstString sym_name = sym->GetName();
470   if (!sym_name)
471     return thread_plan_sp;
472 
473   SymbolContextList target_symbols;
474   Target &target = thread.GetProcess()->GetTarget();
475   const ModuleList &images = target.GetImages();
476 
477   images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
478   size_t num_targets = target_symbols.GetSize();
479   if (!num_targets)
480     return thread_plan_sp;
481 
482   typedef std::vector<lldb::addr_t> AddressVector;
483   AddressVector addrs;
484   for (size_t i = 0; i < num_targets; ++i) {
485     SymbolContext context;
486     AddressRange range;
487     if (target_symbols.GetContextAtIndex(i, context)) {
488       context.GetAddressRange(eSymbolContextEverything, 0, false, range);
489       lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
490       if (addr != LLDB_INVALID_ADDRESS)
491         addrs.push_back(addr);
492     }
493   }
494 
495   if (addrs.size() > 0) {
496     AddressVector::iterator start = addrs.begin();
497     AddressVector::iterator end = addrs.end();
498 
499     llvm::sort(start, end);
500     addrs.erase(std::unique(start, end), end);
501     thread_plan_sp.reset(new ThreadPlanRunToAddress(thread, addrs, stop));
502   }
503 
504   return thread_plan_sp;
505 }
506 
507 void DynamicLoaderPOSIXDYLD::LoadVDSO() {
508   if (m_vdso_base == LLDB_INVALID_ADDRESS)
509     return;
510 
511   FileSpec file("[vdso]");
512 
513   MemoryRegionInfo info;
514   Status status = m_process->GetMemoryRegionInfo(m_vdso_base, info);
515   if (status.Fail()) {
516     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
517     LLDB_LOG(log, "Failed to get vdso region info: {0}", status);
518     return;
519   }
520 
521   if (ModuleSP module_sp = m_process->ReadModuleFromMemory(
522           file, m_vdso_base, info.GetRange().GetByteSize())) {
523     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_vdso_base, false);
524     m_process->GetTarget().GetImages().AppendIfNeeded(module_sp);
525   }
526 }
527 
528 ModuleSP DynamicLoaderPOSIXDYLD::LoadInterpreterModule() {
529   if (m_interpreter_base == LLDB_INVALID_ADDRESS)
530     return nullptr;
531 
532   MemoryRegionInfo info;
533   Target &target = m_process->GetTarget();
534   Status status = m_process->GetMemoryRegionInfo(m_interpreter_base, info);
535   if (status.Fail() || info.GetMapped() != MemoryRegionInfo::eYes ||
536       info.GetName().IsEmpty()) {
537     Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
538     LLDB_LOG(log, "Failed to get interpreter region info: {0}", status);
539     return nullptr;
540   }
541 
542   FileSpec file(info.GetName().GetCString());
543   ModuleSpec module_spec(file, target.GetArchitecture());
544 
545   if (ModuleSP module_sp = target.GetSharedModule(module_spec)) {
546     UpdateLoadedSections(module_sp, LLDB_INVALID_ADDRESS, m_interpreter_base,
547                          false);
548     return module_sp;
549   }
550   return nullptr;
551 }
552 
553 void DynamicLoaderPOSIXDYLD::LoadAllCurrentModules() {
554   DYLDRendezvous::iterator I;
555   DYLDRendezvous::iterator E;
556   ModuleList module_list;
557   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
558 
559   LoadVDSO();
560 
561   if (!m_rendezvous.Resolve()) {
562     if (log)
563       log->Printf("DynamicLoaderPOSIXDYLD::%s unable to resolve POSIX DYLD "
564                   "rendezvous address",
565                   __FUNCTION__);
566     return;
567   }
568 
569   // The rendezvous class doesn't enumerate the main module, so track that
570   // ourselves here.
571   ModuleSP executable = GetTargetExecutable();
572   m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
573 
574   std::vector<FileSpec> module_names;
575   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
576     module_names.push_back(I->file_spec);
577   m_process->PrefetchModuleSpecs(
578       module_names, m_process->GetTarget().GetArchitecture().GetTriple());
579 
580   for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I) {
581     ModuleSP module_sp =
582         LoadModuleAtAddress(I->file_spec, I->link_addr, I->base_addr, true);
583     if (module_sp.get()) {
584       LLDB_LOG(log, "LoadAllCurrentModules loading module: {0}",
585                I->file_spec.GetFilename());
586       module_list.Append(module_sp);
587     } else {
588       Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
589       if (log)
590         log->Printf(
591             "DynamicLoaderPOSIXDYLD::%s failed loading module %s at 0x%" PRIx64,
592             __FUNCTION__, I->file_spec.GetCString(), I->base_addr);
593     }
594   }
595 
596   m_process->GetTarget().ModulesDidLoad(module_list);
597 }
598 
599 addr_t DynamicLoaderPOSIXDYLD::ComputeLoadOffset() {
600   addr_t virt_entry;
601 
602   if (m_load_offset != LLDB_INVALID_ADDRESS)
603     return m_load_offset;
604 
605   if ((virt_entry = GetEntryPoint()) == LLDB_INVALID_ADDRESS)
606     return LLDB_INVALID_ADDRESS;
607 
608   ModuleSP module = m_process->GetTarget().GetExecutableModule();
609   if (!module)
610     return LLDB_INVALID_ADDRESS;
611 
612   ObjectFile *exe = module->GetObjectFile();
613   if (!exe)
614     return LLDB_INVALID_ADDRESS;
615 
616   Address file_entry = exe->GetEntryPointAddress();
617 
618   if (!file_entry.IsValid())
619     return LLDB_INVALID_ADDRESS;
620 
621   m_load_offset = virt_entry - file_entry.GetFileAddress();
622   return m_load_offset;
623 }
624 
625 void DynamicLoaderPOSIXDYLD::EvalSpecialModulesStatus() {
626   auto I = m_auxv->FindEntry(AuxVector::AUXV_AT_SYSINFO_EHDR);
627   if (I != m_auxv->end() && I->value != 0)
628     m_vdso_base = I->value;
629 
630   I = m_auxv->FindEntry(AuxVector::AUXV_AT_BASE);
631   if (I != m_auxv->end() && I->value != 0)
632     m_interpreter_base = I->value;
633 }
634 
635 addr_t DynamicLoaderPOSIXDYLD::GetEntryPoint() {
636   if (m_entry_point != LLDB_INVALID_ADDRESS)
637     return m_entry_point;
638 
639   if (m_auxv.get() == NULL)
640     return LLDB_INVALID_ADDRESS;
641 
642   AuxVector::iterator I = m_auxv->FindEntry(AuxVector::AUXV_AT_ENTRY);
643 
644   if (I == m_auxv->end())
645     return LLDB_INVALID_ADDRESS;
646 
647   m_entry_point = static_cast<addr_t>(I->value);
648 
649   const ArchSpec &arch = m_process->GetTarget().GetArchitecture();
650 
651   // On ppc64, the entry point is actually a descriptor.  Dereference it.
652   if (arch.GetMachine() == llvm::Triple::ppc64)
653     m_entry_point = ReadUnsignedIntWithSizeInBytes(m_entry_point, 8);
654 
655   return m_entry_point;
656 }
657 
658 lldb::addr_t
659 DynamicLoaderPOSIXDYLD::GetThreadLocalData(const lldb::ModuleSP module_sp,
660                                            const lldb::ThreadSP thread,
661                                            lldb::addr_t tls_file_addr) {
662   auto it = m_loaded_modules.find(module_sp);
663   if (it == m_loaded_modules.end())
664     return LLDB_INVALID_ADDRESS;
665 
666   addr_t link_map = it->second;
667   if (link_map == LLDB_INVALID_ADDRESS)
668     return LLDB_INVALID_ADDRESS;
669 
670   const DYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
671   if (!metadata.valid)
672     return LLDB_INVALID_ADDRESS;
673 
674   // Get the thread pointer.
675   addr_t tp = thread->GetThreadPointer();
676   if (tp == LLDB_INVALID_ADDRESS)
677     return LLDB_INVALID_ADDRESS;
678 
679   // Find the module's modid.
680   int modid_size = 4; // FIXME(spucci): This isn't right for big-endian 64-bit
681   int64_t modid = ReadUnsignedIntWithSizeInBytes(
682       link_map + metadata.modid_offset, modid_size);
683   if (modid == -1)
684     return LLDB_INVALID_ADDRESS;
685 
686   // Lookup the DTV structure for this thread.
687   addr_t dtv_ptr = tp + metadata.dtv_offset;
688   addr_t dtv = ReadPointer(dtv_ptr);
689   if (dtv == LLDB_INVALID_ADDRESS)
690     return LLDB_INVALID_ADDRESS;
691 
692   // Find the TLS block for this module.
693   addr_t dtv_slot = dtv + metadata.dtv_slot_size * modid;
694   addr_t tls_block = ReadPointer(dtv_slot + metadata.tls_offset);
695 
696   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
697   if (log)
698     log->Printf("DynamicLoaderPOSIXDYLD::Performed TLS lookup: "
699                 "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64
700                 ", modid=%" PRId64 ", tls_block=0x%" PRIx64 "\n",
701                 module_sp->GetObjectName().AsCString(""), link_map, tp,
702                 (int64_t)modid, tls_block);
703 
704   if (tls_block == LLDB_INVALID_ADDRESS)
705     return LLDB_INVALID_ADDRESS;
706   else
707     return tls_block + tls_file_addr;
708 }
709 
710 void DynamicLoaderPOSIXDYLD::ResolveExecutableModule(
711     lldb::ModuleSP &module_sp) {
712   Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
713 
714   if (m_process == nullptr)
715     return;
716 
717   auto &target = m_process->GetTarget();
718   const auto platform_sp = target.GetPlatform();
719 
720   ProcessInstanceInfo process_info;
721   if (!m_process->GetProcessInfo(process_info)) {
722     if (log)
723       log->Printf("DynamicLoaderPOSIXDYLD::%s - failed to get process info for "
724                   "pid %" PRIu64,
725                   __FUNCTION__, m_process->GetID());
726     return;
727   }
728 
729   if (log)
730     log->Printf("DynamicLoaderPOSIXDYLD::%s - got executable by pid %" PRIu64
731                 ": %s",
732                 __FUNCTION__, m_process->GetID(),
733                 process_info.GetExecutableFile().GetPath().c_str());
734 
735   ModuleSpec module_spec(process_info.GetExecutableFile(),
736                          process_info.GetArchitecture());
737   if (module_sp && module_sp->MatchesModuleSpec(module_spec))
738     return;
739 
740   const auto executable_search_paths(Target::GetDefaultExecutableSearchPaths());
741   auto error = platform_sp->ResolveExecutable(
742       module_spec, module_sp,
743       !executable_search_paths.IsEmpty() ? &executable_search_paths : nullptr);
744   if (error.Fail()) {
745     StreamString stream;
746     module_spec.Dump(stream);
747 
748     if (log)
749       log->Printf("DynamicLoaderPOSIXDYLD::%s - failed to resolve executable "
750                   "with module spec \"%s\": %s",
751                   __FUNCTION__, stream.GetData(), error.AsCString());
752     return;
753   }
754 
755   target.SetExecutableModule(module_sp, eLoadDependentsNo);
756 }
757 
758 bool DynamicLoaderPOSIXDYLD::AlwaysRelyOnEHUnwindInfo(
759     lldb_private::SymbolContext &sym_ctx) {
760   ModuleSP module_sp;
761   if (sym_ctx.symbol)
762     module_sp = sym_ctx.symbol->GetAddressRef().GetModule();
763   if (!module_sp && sym_ctx.function)
764     module_sp =
765         sym_ctx.function->GetAddressRange().GetBaseAddress().GetModule();
766   if (!module_sp)
767     return false;
768 
769   return module_sp->GetFileSpec().GetPath() == "[vdso]";
770 }
771