1 //===-- DynamicLoaderHexagonDYLD.cpp ----------------------------*- C++ -*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 #include "lldb/Breakpoint/BreakpointLocation.h"
10 #include "lldb/Core/Module.h"
11 #include "lldb/Core/ModuleSpec.h"
12 #include "lldb/Core/PluginManager.h"
13 #include "lldb/Core/Section.h"
14 #include "lldb/Symbol/ObjectFile.h"
15 #include "lldb/Target/Process.h"
16 #include "lldb/Target/Target.h"
17 #include "lldb/Target/Thread.h"
18 #include "lldb/Target/ThreadPlanRunToAddress.h"
19 #include "lldb/Utility/Log.h"
21 #include "DynamicLoaderHexagonDYLD.h"
26 using namespace lldb_private;
30 // Notes about hexagon dynamic loading:
32 // When we connect to a target we find the dyld breakpoint address. We put
34 // breakpoint there with a callback 'RendezvousBreakpointHit()'.
36 // It is possible to find the dyld structure address from the ELF symbol
38 // but in the case of the simulator it has not been initialized before the
39 // target calls dlinit().
41 // We can only safely parse the dyld structure after we hit the dyld
43 // since at that time we know dlinit() must have been called.
46 // Find the load address of a symbol
47 static lldb::addr_t findSymbolAddress(Process *proc, ConstString findName) {
48 assert(proc != nullptr);
50 ModuleSP module = proc->GetTarget().GetExecutableModule();
51 assert(module.get() != nullptr);
53 ObjectFile *exe = module->GetObjectFile();
54 assert(exe != nullptr);
56 lldb_private::Symtab *symtab = exe->GetSymtab();
57 assert(symtab != nullptr);
59 for (size_t i = 0; i < symtab->GetNumSymbols(); i++) {
60 const Symbol *sym = symtab->SymbolAtIndex(i);
61 assert(sym != nullptr);
62 ConstString symName = sym->GetName();
64 if (ConstString::Compare(findName, symName) == 0) {
65 Address addr = sym->GetAddress();
66 return addr.GetLoadAddress(&proc->GetTarget());
69 return LLDB_INVALID_ADDRESS;
72 void DynamicLoaderHexagonDYLD::Initialize() {
73 PluginManager::RegisterPlugin(GetPluginNameStatic(),
74 GetPluginDescriptionStatic(), CreateInstance);
77 void DynamicLoaderHexagonDYLD::Terminate() {}
79 lldb_private::ConstString DynamicLoaderHexagonDYLD::GetPluginName() {
80 return GetPluginNameStatic();
83 lldb_private::ConstString DynamicLoaderHexagonDYLD::GetPluginNameStatic() {
84 static ConstString g_name("hexagon-dyld");
88 const char *DynamicLoaderHexagonDYLD::GetPluginDescriptionStatic() {
89 return "Dynamic loader plug-in that watches for shared library "
90 "loads/unloads in Hexagon processes.";
93 uint32_t DynamicLoaderHexagonDYLD::GetPluginVersion() { return 1; }
95 DynamicLoader *DynamicLoaderHexagonDYLD::CreateInstance(Process *process,
99 const llvm::Triple &triple_ref =
100 process->GetTarget().GetArchitecture().GetTriple();
101 if (triple_ref.getArch() == llvm::Triple::hexagon)
106 return new DynamicLoaderHexagonDYLD(process);
110 DynamicLoaderHexagonDYLD::DynamicLoaderHexagonDYLD(Process *process)
111 : DynamicLoader(process), m_rendezvous(process),
112 m_load_offset(LLDB_INVALID_ADDRESS), m_entry_point(LLDB_INVALID_ADDRESS),
113 m_dyld_bid(LLDB_INVALID_BREAK_ID) {}
115 DynamicLoaderHexagonDYLD::~DynamicLoaderHexagonDYLD() {
116 if (m_dyld_bid != LLDB_INVALID_BREAK_ID) {
117 m_process->GetTarget().RemoveBreakpointByID(m_dyld_bid);
118 m_dyld_bid = LLDB_INVALID_BREAK_ID;
122 void DynamicLoaderHexagonDYLD::DidAttach() {
126 executable = GetTargetExecutable();
128 // Find the difference between the desired load address in the elf file and
129 // the real load address in memory
130 load_offset = ComputeLoadOffset();
132 // Check that there is a valid executable
133 if (executable.get() == nullptr)
136 // Disable JIT for hexagon targets because its not supported
137 m_process->SetCanJIT(false);
139 // Enable Interpreting of function call expressions
140 m_process->SetCanInterpretFunctionCalls(true);
142 // Add the current executable to the module list
143 ModuleList module_list;
144 module_list.Append(executable);
146 // Map the loaded sections of this executable
147 if (load_offset != LLDB_INVALID_ADDRESS)
148 UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset, true);
151 // Load into LLDB all of the currently loaded executables in the stub
152 LoadAllCurrentModules();
155 // Callback for the target to give it the loaded module list
156 m_process->GetTarget().ModulesDidLoad(module_list);
158 // Try to set a breakpoint at the rendezvous breakpoint. DidLaunch uses
159 // ProbeEntry() instead. That sets a breakpoint, at the dyld breakpoint
160 // address, with a callback so that when hit, the dyld structure can be
162 if (!SetRendezvousBreakpoint()) {
167 void DynamicLoaderHexagonDYLD::DidLaunch() {}
169 /// Checks to see if the target module has changed, updates the target
170 /// accordingly and returns the target executable module.
171 ModuleSP DynamicLoaderHexagonDYLD::GetTargetExecutable() {
172 Target &target = m_process->GetTarget();
173 ModuleSP executable = target.GetExecutableModule();
175 // There is no executable
176 if (!executable.get())
179 // The target executable file does not exits
180 if (!FileSystem::Instance().Exists(executable->GetFileSpec()))
183 // Prep module for loading
184 ModuleSpec module_spec(executable->GetFileSpec(),
185 executable->GetArchitecture());
186 ModuleSP module_sp(new Module(module_spec));
188 // Check if the executable has changed and set it to the target executable if
190 if (module_sp.get() && module_sp->GetUUID().IsValid() &&
191 executable->GetUUID().IsValid()) {
192 // if the executable has changed ??
193 if (module_sp->GetUUID() != executable->GetUUID())
195 } else if (executable->FileHasChanged())
198 if (executable.get())
201 // TODO: What case is this code used?
202 executable = target.GetOrCreateModule(module_spec, true /* notify */);
203 if (executable.get() != target.GetExecutableModulePointer()) {
204 // Don't load dependent images since we are in dyld where we will know and
205 // find out about all images that are loaded
206 target.SetExecutableModule(executable, eLoadDependentsNo);
212 // AD: Needs to be updated?
213 Status DynamicLoaderHexagonDYLD::CanLoadImage() { return Status(); }
215 void DynamicLoaderHexagonDYLD::UpdateLoadedSections(ModuleSP module,
216 addr_t link_map_addr,
218 bool base_addr_is_offset) {
219 Target &target = m_process->GetTarget();
220 const SectionList *sections = GetSectionListFromModule(module);
222 assert(sections && "SectionList missing from loaded module.");
224 m_loaded_modules[module] = link_map_addr;
226 const size_t num_sections = sections->GetSize();
228 for (unsigned i = 0; i < num_sections; ++i) {
229 SectionSP section_sp(sections->GetSectionAtIndex(i));
230 lldb::addr_t new_load_addr = section_sp->GetFileAddress() + base_addr;
233 // since our memory map starts from address 0, we must not ignore
234 // sections that load to address 0. This violates the reference
235 // ELF spec, however is used for Hexagon.
237 // If the file address of the section is zero then this is not an
238 // allocatable/loadable section (property of ELF sh_addr). Skip it.
239 // if (new_load_addr == base_addr)
242 target.SetSectionLoadAddress(section_sp, new_load_addr);
246 /// Removes the loaded sections from the target in \p module.
248 /// \param module The module to traverse.
249 void DynamicLoaderHexagonDYLD::UnloadSections(const ModuleSP module) {
250 Target &target = m_process->GetTarget();
251 const SectionList *sections = GetSectionListFromModule(module);
253 assert(sections && "SectionList missing from unloaded module.");
255 m_loaded_modules.erase(module);
257 const size_t num_sections = sections->GetSize();
258 for (size_t i = 0; i < num_sections; ++i) {
259 SectionSP section_sp(sections->GetSectionAtIndex(i));
260 target.SetSectionUnloaded(section_sp);
264 // Place a breakpoint on <_rtld_debug_state>
265 bool DynamicLoaderHexagonDYLD::SetRendezvousBreakpoint() {
266 Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
268 // This is the original code, which want to look in the rendezvous structure
269 // to find the breakpoint address. Its backwards for us, since we can easily
270 // find the breakpoint address, since it is exported in our executable. We
271 // however know that we cant read the Rendezvous structure until we have hit
272 // the breakpoint once.
273 const ConstString dyldBpName("_rtld_debug_state");
274 addr_t break_addr = findSymbolAddress(m_process, dyldBpName);
276 Target &target = m_process->GetTarget();
278 // Do not try to set the breakpoint if we don't know where to put it
279 if (break_addr == LLDB_INVALID_ADDRESS) {
281 log->Printf("Unable to locate _rtld_debug_state breakpoint address");
286 // Save the address of the rendezvous structure
287 m_rendezvous.SetBreakAddress(break_addr);
289 // If we haven't set the breakpoint before then set it
290 if (m_dyld_bid == LLDB_INVALID_BREAK_ID) {
291 Breakpoint *dyld_break =
292 target.CreateBreakpoint(break_addr, true, false).get();
293 dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
294 dyld_break->SetBreakpointKind("shared-library-event");
295 m_dyld_bid = dyld_break->GetID();
297 // Make sure our breakpoint is at the right address.
298 assert(target.GetBreakpointByID(m_dyld_bid)
299 ->FindLocationByAddress(break_addr)
301 .GetID() == m_dyld_bid);
303 if (log && dyld_break == nullptr)
304 log->Printf("Failed to create _rtld_debug_state breakpoint");
306 // check we have successfully set bp
307 return (dyld_break != nullptr);
309 // rendezvous already set
313 // We have just hit our breakpoint at <_rtld_debug_state>
314 bool DynamicLoaderHexagonDYLD::RendezvousBreakpointHit(
315 void *baton, StoppointCallbackContext *context, user_id_t break_id,
316 user_id_t break_loc_id) {
317 Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
320 log->Printf("Rendezvous breakpoint hit!");
322 DynamicLoaderHexagonDYLD *dyld_instance = nullptr;
323 dyld_instance = static_cast<DynamicLoaderHexagonDYLD *>(baton);
325 // if the dyld_instance is still not valid then try to locate it on the
327 if (!dyld_instance->m_rendezvous.IsValid()) {
328 Process *proc = dyld_instance->m_process;
330 const ConstString dyldStructName("_rtld_debug");
331 addr_t structAddr = findSymbolAddress(proc, dyldStructName);
333 if (structAddr != LLDB_INVALID_ADDRESS) {
334 dyld_instance->m_rendezvous.SetRendezvousAddress(structAddr);
337 log->Printf("Found _rtld_debug structure @ 0x%08" PRIx64, structAddr);
340 log->Printf("Unable to resolve the _rtld_debug structure");
344 dyld_instance->RefreshModules();
346 // Return true to stop the target, false to just let the target run.
347 return dyld_instance->GetStopWhenImagesChange();
350 /// Helper method for RendezvousBreakpointHit. Updates LLDB's current set
351 /// of loaded modules.
352 void DynamicLoaderHexagonDYLD::RefreshModules() {
353 Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
355 if (!m_rendezvous.Resolve())
358 HexagonDYLDRendezvous::iterator I;
359 HexagonDYLDRendezvous::iterator E;
361 ModuleList &loaded_modules = m_process->GetTarget().GetImages();
363 if (m_rendezvous.ModulesDidLoad()) {
364 ModuleList new_modules;
366 E = m_rendezvous.loaded_end();
367 for (I = m_rendezvous.loaded_begin(); I != E; ++I) {
368 FileSpec file(I->path);
369 FileSystem::Instance().Resolve(file);
371 LoadModuleAtAddress(file, I->link_addr, I->base_addr, true);
372 if (module_sp.get()) {
373 loaded_modules.AppendIfNeeded(module_sp);
374 new_modules.Append(module_sp);
378 log->Printf("Target is loading '%s'", I->path.c_str());
379 if (!module_sp.get())
380 log->Printf("LLDB failed to load '%s'", I->path.c_str());
382 log->Printf("LLDB successfully loaded '%s'", I->path.c_str());
385 m_process->GetTarget().ModulesDidLoad(new_modules);
388 if (m_rendezvous.ModulesDidUnload()) {
389 ModuleList old_modules;
391 E = m_rendezvous.unloaded_end();
392 for (I = m_rendezvous.unloaded_begin(); I != E; ++I) {
393 FileSpec file(I->path);
394 FileSystem::Instance().Resolve(file);
395 ModuleSpec module_spec(file);
396 ModuleSP module_sp = loaded_modules.FindFirstModule(module_spec);
398 if (module_sp.get()) {
399 old_modules.Append(module_sp);
400 UnloadSections(module_sp);
404 log->Printf("Target is unloading '%s'", I->path.c_str());
406 loaded_modules.Remove(old_modules);
407 m_process->GetTarget().ModulesDidUnload(old_modules, false);
411 // AD: This is very different to the Static Loader code.
412 // It may be wise to look over this and its relation to stack
415 DynamicLoaderHexagonDYLD::GetStepThroughTrampolinePlan(Thread &thread,
417 ThreadPlanSP thread_plan_sp;
419 StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
420 const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
421 Symbol *sym = context.symbol;
423 if (sym == nullptr || !sym->IsTrampoline())
424 return thread_plan_sp;
426 const ConstString sym_name = sym->GetMangled().GetName(
427 lldb::eLanguageTypeUnknown, Mangled::ePreferMangled);
429 return thread_plan_sp;
431 SymbolContextList target_symbols;
432 Target &target = thread.GetProcess()->GetTarget();
433 const ModuleList &images = target.GetImages();
435 images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
436 size_t num_targets = target_symbols.GetSize();
438 return thread_plan_sp;
440 typedef std::vector<lldb::addr_t> AddressVector;
442 for (size_t i = 0; i < num_targets; ++i) {
443 SymbolContext context;
445 if (target_symbols.GetContextAtIndex(i, context)) {
446 context.GetAddressRange(eSymbolContextEverything, 0, false, range);
447 lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
448 if (addr != LLDB_INVALID_ADDRESS)
449 addrs.push_back(addr);
453 if (addrs.size() > 0) {
454 AddressVector::iterator start = addrs.begin();
455 AddressVector::iterator end = addrs.end();
457 llvm::sort(start, end);
458 addrs.erase(std::unique(start, end), end);
460 std::make_shared<ThreadPlanRunToAddress>(thread, addrs, stop);
463 return thread_plan_sp;
466 /// Helper for the entry breakpoint callback. Resolves the load addresses
467 /// of all dependent modules.
468 void DynamicLoaderHexagonDYLD::LoadAllCurrentModules() {
469 HexagonDYLDRendezvous::iterator I;
470 HexagonDYLDRendezvous::iterator E;
471 ModuleList module_list;
473 if (!m_rendezvous.Resolve()) {
474 Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
477 "DynamicLoaderHexagonDYLD::%s unable to resolve rendezvous address",
482 // The rendezvous class doesn't enumerate the main module, so track that
484 ModuleSP executable = GetTargetExecutable();
485 m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
487 for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I) {
488 const char *module_path = I->path.c_str();
489 FileSpec file(module_path);
491 LoadModuleAtAddress(file, I->link_addr, I->base_addr, true);
492 if (module_sp.get()) {
493 module_list.Append(module_sp);
495 Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
497 log->Printf("DynamicLoaderHexagonDYLD::%s failed loading module %s at "
499 __FUNCTION__, module_path, I->base_addr);
503 m_process->GetTarget().ModulesDidLoad(module_list);
506 /// Computes a value for m_load_offset returning the computed address on
507 /// success and LLDB_INVALID_ADDRESS on failure.
508 addr_t DynamicLoaderHexagonDYLD::ComputeLoadOffset() {
509 // Here we could send a GDB packet to know the load offset
511 // send: $qOffsets#4b
512 // get: Text=0;Data=0;Bss=0
514 // Currently qOffsets is not supported by pluginProcessGDBRemote
519 // Here we must try to read the entry point directly from the elf header. This
520 // is possible if the process is not relocatable or dynamically linked.
522 // an alternative is to look at the PC if we can be sure that we have connected
523 // when the process is at the entry point.
524 // I dont think that is reliable for us.
525 addr_t DynamicLoaderHexagonDYLD::GetEntryPoint() {
526 if (m_entry_point != LLDB_INVALID_ADDRESS)
527 return m_entry_point;
528 // check we have a valid process
529 if (m_process == nullptr)
530 return LLDB_INVALID_ADDRESS;
531 // Get the current executable module
532 Module &module = *(m_process->GetTarget().GetExecutableModule().get());
533 // Get the object file (elf file) for this module
534 lldb_private::ObjectFile &object = *(module.GetObjectFile());
535 // Check if the file is executable (ie, not shared object or relocatable)
536 if (object.IsExecutable()) {
537 // Get the entry point address for this object
538 lldb_private::Address entry = object.GetEntryPointAddress();
539 // Return the entry point address
540 return entry.GetFileAddress();
542 // No idea so back out
543 return LLDB_INVALID_ADDRESS;
546 const SectionList *DynamicLoaderHexagonDYLD::GetSectionListFromModule(
547 const ModuleSP module) const {
548 SectionList *sections = nullptr;
550 ObjectFile *obj_file = module->GetObjectFile();
552 sections = obj_file->GetSectionList();
558 static int ReadInt(Process *process, addr_t addr) {
560 int value = (int)process->ReadUnsignedIntegerFromMemory(
561 addr, sizeof(uint32_t), 0, error);
569 DynamicLoaderHexagonDYLD::GetThreadLocalData(const lldb::ModuleSP module,
570 const lldb::ThreadSP thread,
571 lldb::addr_t tls_file_addr) {
572 auto it = m_loaded_modules.find(module);
573 if (it == m_loaded_modules.end())
574 return LLDB_INVALID_ADDRESS;
576 addr_t link_map = it->second;
577 if (link_map == LLDB_INVALID_ADDRESS)
578 return LLDB_INVALID_ADDRESS;
580 const HexagonDYLDRendezvous::ThreadInfo &metadata =
581 m_rendezvous.GetThreadInfo();
583 return LLDB_INVALID_ADDRESS;
585 // Get the thread pointer.
586 addr_t tp = thread->GetThreadPointer();
587 if (tp == LLDB_INVALID_ADDRESS)
588 return LLDB_INVALID_ADDRESS;
590 // Find the module's modid.
591 int modid = ReadInt(m_process, link_map + metadata.modid_offset);
593 return LLDB_INVALID_ADDRESS;
595 // Lookup the DTV structure for this thread.
596 addr_t dtv_ptr = tp + metadata.dtv_offset;
597 addr_t dtv = ReadPointer(dtv_ptr);
598 if (dtv == LLDB_INVALID_ADDRESS)
599 return LLDB_INVALID_ADDRESS;
601 // Find the TLS block for this module.
602 addr_t dtv_slot = dtv + metadata.dtv_slot_size * modid;
603 addr_t tls_block = ReadPointer(dtv_slot + metadata.tls_offset);
605 Module *mod = module.get();
606 Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
608 log->Printf("DynamicLoaderHexagonDYLD::Performed TLS lookup: "
609 "module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64
610 ", modid=%i, tls_block=0x%" PRIx64,
611 mod->GetObjectName().AsCString(""), link_map, tp, modid,
614 if (tls_block == LLDB_INVALID_ADDRESS)
615 return LLDB_INVALID_ADDRESS;
617 return tls_block + tls_file_addr;