1 //===-- JITLoaderGDB.cpp --------------------------------------------------===//
2 //
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
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "JITLoaderGDB.h"
10 #include "Plugins/ObjectFile/Mach-O/ObjectFileMachO.h"
11 #include "lldb/Breakpoint/Breakpoint.h"
12 #include "lldb/Core/Module.h"
13 #include "lldb/Core/ModuleSpec.h"
14 #include "lldb/Core/PluginManager.h"
15 #include "lldb/Core/Section.h"
16 #include "lldb/Interpreter/OptionValueProperties.h"
17 #include "lldb/Symbol/ObjectFile.h"
18 #include "lldb/Symbol/Symbol.h"
19 #include "lldb/Symbol/SymbolContext.h"
20 #include "lldb/Symbol/SymbolVendor.h"
21 #include "lldb/Target/Process.h"
22 #include "lldb/Target/SectionLoadList.h"
23 #include "lldb/Target/Target.h"
24 #include "lldb/Utility/DataBufferHeap.h"
25 #include "lldb/Utility/LLDBAssert.h"
26 #include "lldb/Utility/LLDBLog.h"
27 #include "lldb/Utility/Log.h"
28 #include "lldb/Utility/StreamString.h"
29 #include "llvm/Support/MathExtras.h"
30
31 #include <memory>
32
33 using namespace lldb;
34 using namespace lldb_private;
35
36 LLDB_PLUGIN_DEFINE(JITLoaderGDB)
37
38 // Debug Interface Structures
39 enum jit_actions_t { JIT_NOACTION = 0, JIT_REGISTER_FN, JIT_UNREGISTER_FN };
40
41 template <typename ptr_t> struct jit_code_entry {
42 ptr_t next_entry; // pointer
43 ptr_t prev_entry; // pointer
44 ptr_t symfile_addr; // pointer
45 uint64_t symfile_size;
46 };
47
48 template <typename ptr_t> struct jit_descriptor {
49 uint32_t version;
50 uint32_t action_flag; // Values are jit_action_t
51 ptr_t relevant_entry; // pointer
52 ptr_t first_entry; // pointer
53 };
54
55 namespace {
56 enum EnableJITLoaderGDB {
57 eEnableJITLoaderGDBDefault,
58 eEnableJITLoaderGDBOn,
59 eEnableJITLoaderGDBOff,
60 };
61
62 static constexpr OptionEnumValueElement g_enable_jit_loader_gdb_enumerators[] =
63 {
64 {
65 eEnableJITLoaderGDBDefault,
66 "default",
67 "Enable JIT compilation interface for all platforms except macOS",
68 },
69 {
70 eEnableJITLoaderGDBOn,
71 "on",
72 "Enable JIT compilation interface",
73 },
74 {
75 eEnableJITLoaderGDBOff,
76 "off",
77 "Disable JIT compilation interface",
78 },
79 };
80
81 #define LLDB_PROPERTIES_jitloadergdb
82 #include "JITLoaderGDBProperties.inc"
83
84 enum {
85 #define LLDB_PROPERTIES_jitloadergdb
86 #include "JITLoaderGDBPropertiesEnum.inc"
87 ePropertyEnableJITBreakpoint
88 };
89
90 class PluginProperties : public Properties {
91 public:
GetSettingName()92 static ConstString GetSettingName() {
93 return ConstString(JITLoaderGDB::GetPluginNameStatic());
94 }
95
PluginProperties()96 PluginProperties() {
97 m_collection_sp = std::make_shared<OptionValueProperties>(GetSettingName());
98 m_collection_sp->Initialize(g_jitloadergdb_properties);
99 }
100
GetEnable() const101 EnableJITLoaderGDB GetEnable() const {
102 return (EnableJITLoaderGDB)m_collection_sp->GetPropertyAtIndexAsEnumeration(
103 nullptr, ePropertyEnable,
104 g_jitloadergdb_properties[ePropertyEnable].default_uint_value);
105 }
106 };
107 } // namespace
108
GetGlobalPluginProperties()109 static PluginProperties &GetGlobalPluginProperties() {
110 static PluginProperties g_settings;
111 return g_settings;
112 }
113
114 template <typename ptr_t>
ReadJITEntry(const addr_t from_addr,Process * process,jit_code_entry<ptr_t> * entry)115 static bool ReadJITEntry(const addr_t from_addr, Process *process,
116 jit_code_entry<ptr_t> *entry) {
117 lldbassert(from_addr % sizeof(ptr_t) == 0);
118
119 ArchSpec::Core core = process->GetTarget().GetArchitecture().GetCore();
120 bool i386_target = ArchSpec::kCore_x86_32_first <= core &&
121 core <= ArchSpec::kCore_x86_32_last;
122 uint8_t uint64_align_bytes = i386_target ? 4 : 8;
123 const size_t data_byte_size =
124 llvm::alignTo(sizeof(ptr_t) * 3, uint64_align_bytes) + sizeof(uint64_t);
125
126 Status error;
127 DataBufferHeap data(data_byte_size, 0);
128 size_t bytes_read = process->ReadMemory(from_addr, data.GetBytes(),
129 data.GetByteSize(), error);
130 if (bytes_read != data_byte_size || !error.Success())
131 return false;
132
133 DataExtractor extractor(data.GetBytes(), data.GetByteSize(),
134 process->GetByteOrder(), sizeof(ptr_t));
135 lldb::offset_t offset = 0;
136 entry->next_entry = extractor.GetAddress(&offset);
137 entry->prev_entry = extractor.GetAddress(&offset);
138 entry->symfile_addr = extractor.GetAddress(&offset);
139 offset = llvm::alignTo(offset, uint64_align_bytes);
140 entry->symfile_size = extractor.GetU64(&offset);
141
142 return true;
143 }
144
JITLoaderGDB(lldb_private::Process * process)145 JITLoaderGDB::JITLoaderGDB(lldb_private::Process *process)
146 : JITLoader(process), m_jit_objects(),
147 m_jit_break_id(LLDB_INVALID_BREAK_ID),
148 m_jit_descriptor_addr(LLDB_INVALID_ADDRESS) {}
149
~JITLoaderGDB()150 JITLoaderGDB::~JITLoaderGDB() {
151 if (LLDB_BREAK_ID_IS_VALID(m_jit_break_id))
152 m_process->GetTarget().RemoveBreakpointByID(m_jit_break_id);
153 }
154
DebuggerInitialize(Debugger & debugger)155 void JITLoaderGDB::DebuggerInitialize(Debugger &debugger) {
156 if (!PluginManager::GetSettingForJITLoaderPlugin(
157 debugger, PluginProperties::GetSettingName())) {
158 const bool is_global_setting = true;
159 PluginManager::CreateSettingForJITLoaderPlugin(
160 debugger, GetGlobalPluginProperties().GetValueProperties(),
161 ConstString("Properties for the JIT LoaderGDB plug-in."),
162 is_global_setting);
163 }
164 }
165
DidAttach()166 void JITLoaderGDB::DidAttach() {
167 Target &target = m_process->GetTarget();
168 ModuleList &module_list = target.GetImages();
169 SetJITBreakpoint(module_list);
170 }
171
DidLaunch()172 void JITLoaderGDB::DidLaunch() {
173 Target &target = m_process->GetTarget();
174 ModuleList &module_list = target.GetImages();
175 SetJITBreakpoint(module_list);
176 }
177
ModulesDidLoad(ModuleList & module_list)178 void JITLoaderGDB::ModulesDidLoad(ModuleList &module_list) {
179 if (!DidSetJITBreakpoint() && m_process->IsAlive())
180 SetJITBreakpoint(module_list);
181 }
182
183 // Setup the JIT Breakpoint
SetJITBreakpoint(lldb_private::ModuleList & module_list)184 void JITLoaderGDB::SetJITBreakpoint(lldb_private::ModuleList &module_list) {
185 if (DidSetJITBreakpoint())
186 return;
187
188 Log *log = GetLog(LLDBLog::JITLoader);
189 LLDB_LOGF(log, "JITLoaderGDB::%s looking for JIT register hook",
190 __FUNCTION__);
191
192 addr_t jit_addr = GetSymbolAddress(
193 module_list, ConstString("__jit_debug_register_code"), eSymbolTypeCode);
194 if (jit_addr == LLDB_INVALID_ADDRESS)
195 return;
196
197 m_jit_descriptor_addr = GetSymbolAddress(
198 module_list, ConstString("__jit_debug_descriptor"), eSymbolTypeData);
199 if (m_jit_descriptor_addr == LLDB_INVALID_ADDRESS) {
200 LLDB_LOGF(log, "JITLoaderGDB::%s failed to find JIT descriptor address",
201 __FUNCTION__);
202 return;
203 }
204
205 LLDB_LOGF(log, "JITLoaderGDB::%s setting JIT breakpoint", __FUNCTION__);
206
207 Breakpoint *bp =
208 m_process->GetTarget().CreateBreakpoint(jit_addr, true, false).get();
209 bp->SetCallback(JITDebugBreakpointHit, this, true);
210 bp->SetBreakpointKind("jit-debug-register");
211 m_jit_break_id = bp->GetID();
212
213 ReadJITDescriptor(true);
214 }
215
JITDebugBreakpointHit(void * baton,StoppointCallbackContext * context,user_id_t break_id,user_id_t break_loc_id)216 bool JITLoaderGDB::JITDebugBreakpointHit(void *baton,
217 StoppointCallbackContext *context,
218 user_id_t break_id,
219 user_id_t break_loc_id) {
220 Log *log = GetLog(LLDBLog::JITLoader);
221 LLDB_LOGF(log, "JITLoaderGDB::%s hit JIT breakpoint", __FUNCTION__);
222 JITLoaderGDB *instance = static_cast<JITLoaderGDB *>(baton);
223 return instance->ReadJITDescriptor(false);
224 }
225
updateSectionLoadAddress(const SectionList & section_list,Target & target,uint64_t symbolfile_addr,uint64_t symbolfile_size,uint64_t & vmaddrheuristic,uint64_t & min_addr,uint64_t & max_addr)226 static void updateSectionLoadAddress(const SectionList §ion_list,
227 Target &target, uint64_t symbolfile_addr,
228 uint64_t symbolfile_size,
229 uint64_t &vmaddrheuristic,
230 uint64_t &min_addr, uint64_t &max_addr) {
231 const uint32_t num_sections = section_list.GetSize();
232 for (uint32_t i = 0; i < num_sections; ++i) {
233 SectionSP section_sp(section_list.GetSectionAtIndex(i));
234 if (section_sp) {
235 if (section_sp->IsFake()) {
236 uint64_t lower = (uint64_t)-1;
237 uint64_t upper = 0;
238 updateSectionLoadAddress(section_sp->GetChildren(), target,
239 symbolfile_addr, symbolfile_size,
240 vmaddrheuristic, lower, upper);
241 if (lower < min_addr)
242 min_addr = lower;
243 if (upper > max_addr)
244 max_addr = upper;
245 const lldb::addr_t slide_amount = lower - section_sp->GetFileAddress();
246 section_sp->Slide(slide_amount, false);
247 section_sp->GetChildren().Slide(-slide_amount, false);
248 section_sp->SetByteSize(upper - lower);
249 } else {
250 vmaddrheuristic += 2 << section_sp->GetLog2Align();
251 uint64_t lower;
252 if (section_sp->GetFileAddress() > vmaddrheuristic)
253 lower = section_sp->GetFileAddress();
254 else {
255 lower = symbolfile_addr + section_sp->GetFileOffset();
256 section_sp->SetFileAddress(symbolfile_addr +
257 section_sp->GetFileOffset());
258 }
259 target.SetSectionLoadAddress(section_sp, lower, true);
260 uint64_t upper = lower + section_sp->GetByteSize();
261 if (lower < min_addr)
262 min_addr = lower;
263 if (upper > max_addr)
264 max_addr = upper;
265 // This is an upper bound, but a good enough heuristic
266 vmaddrheuristic += section_sp->GetByteSize();
267 }
268 }
269 }
270 }
271
ReadJITDescriptor(bool all_entries)272 bool JITLoaderGDB::ReadJITDescriptor(bool all_entries) {
273 if (m_process->GetTarget().GetArchitecture().GetAddressByteSize() == 8)
274 return ReadJITDescriptorImpl<uint64_t>(all_entries);
275 else
276 return ReadJITDescriptorImpl<uint32_t>(all_entries);
277 }
278
279 template <typename ptr_t>
ReadJITDescriptorImpl(bool all_entries)280 bool JITLoaderGDB::ReadJITDescriptorImpl(bool all_entries) {
281 if (m_jit_descriptor_addr == LLDB_INVALID_ADDRESS)
282 return false;
283
284 Log *log = GetLog(LLDBLog::JITLoader);
285 Target &target = m_process->GetTarget();
286 ModuleList &module_list = target.GetImages();
287
288 jit_descriptor<ptr_t> jit_desc;
289 const size_t jit_desc_size = sizeof(jit_desc);
290 Status error;
291 size_t bytes_read = m_process->ReadMemory(m_jit_descriptor_addr, &jit_desc,
292 jit_desc_size, error);
293 if (bytes_read != jit_desc_size || !error.Success()) {
294 LLDB_LOGF(log, "JITLoaderGDB::%s failed to read JIT descriptor",
295 __FUNCTION__);
296 return false;
297 }
298
299 jit_actions_t jit_action = (jit_actions_t)jit_desc.action_flag;
300 addr_t jit_relevant_entry = (addr_t)jit_desc.relevant_entry;
301 if (all_entries) {
302 jit_action = JIT_REGISTER_FN;
303 jit_relevant_entry = (addr_t)jit_desc.first_entry;
304 }
305
306 while (jit_relevant_entry != 0) {
307 jit_code_entry<ptr_t> jit_entry;
308 if (!ReadJITEntry(jit_relevant_entry, m_process, &jit_entry)) {
309 LLDB_LOGF(log, "JITLoaderGDB::%s failed to read JIT entry at 0x%" PRIx64,
310 __FUNCTION__, jit_relevant_entry);
311 return false;
312 }
313
314 const addr_t &symbolfile_addr = (addr_t)jit_entry.symfile_addr;
315 const size_t &symbolfile_size = (size_t)jit_entry.symfile_size;
316 ModuleSP module_sp;
317
318 if (jit_action == JIT_REGISTER_FN) {
319 LLDB_LOGF(log,
320 "JITLoaderGDB::%s registering JIT entry at 0x%" PRIx64
321 " (%" PRIu64 " bytes)",
322 __FUNCTION__, symbolfile_addr, (uint64_t)symbolfile_size);
323
324 char jit_name[64];
325 snprintf(jit_name, 64, "JIT(0x%" PRIx64 ")", symbolfile_addr);
326 module_sp = m_process->ReadModuleFromMemory(
327 FileSpec(jit_name), symbolfile_addr, symbolfile_size);
328
329 if (module_sp && module_sp->GetObjectFile()) {
330 // Object formats (like ELF) have no representation for a JIT type.
331 // We will get it wrong, if we deduce it from the header.
332 module_sp->GetObjectFile()->SetType(ObjectFile::eTypeJIT);
333
334 // load the symbol table right away
335 module_sp->GetObjectFile()->GetSymtab();
336
337 m_jit_objects.insert(std::make_pair(symbolfile_addr, module_sp));
338 if (auto image_object_file =
339 llvm::dyn_cast<ObjectFileMachO>(module_sp->GetObjectFile())) {
340 const SectionList *section_list = image_object_file->GetSectionList();
341 if (section_list) {
342 uint64_t vmaddrheuristic = 0;
343 uint64_t lower = (uint64_t)-1;
344 uint64_t upper = 0;
345 updateSectionLoadAddress(*section_list, target, symbolfile_addr,
346 symbolfile_size, vmaddrheuristic, lower,
347 upper);
348 }
349 } else {
350 bool changed = false;
351 module_sp->SetLoadAddress(target, 0, true, changed);
352 }
353
354 module_list.AppendIfNeeded(module_sp);
355
356 ModuleList module_list;
357 module_list.Append(module_sp);
358 target.ModulesDidLoad(module_list);
359 } else {
360 LLDB_LOGF(log,
361 "JITLoaderGDB::%s failed to load module for "
362 "JIT entry at 0x%" PRIx64,
363 __FUNCTION__, symbolfile_addr);
364 }
365 } else if (jit_action == JIT_UNREGISTER_FN) {
366 LLDB_LOGF(log, "JITLoaderGDB::%s unregistering JIT entry at 0x%" PRIx64,
367 __FUNCTION__, symbolfile_addr);
368
369 JITObjectMap::iterator it = m_jit_objects.find(symbolfile_addr);
370 if (it != m_jit_objects.end()) {
371 module_sp = it->second;
372 ObjectFile *image_object_file = module_sp->GetObjectFile();
373 if (image_object_file) {
374 const SectionList *section_list = image_object_file->GetSectionList();
375 if (section_list) {
376 const uint32_t num_sections = section_list->GetSize();
377 for (uint32_t i = 0; i < num_sections; ++i) {
378 SectionSP section_sp(section_list->GetSectionAtIndex(i));
379 if (section_sp) {
380 target.GetSectionLoadList().SetSectionUnloaded(section_sp);
381 }
382 }
383 }
384 }
385 module_list.Remove(module_sp);
386 m_jit_objects.erase(it);
387 }
388 } else if (jit_action == JIT_NOACTION) {
389 // Nothing to do
390 } else {
391 assert(false && "Unknown jit action");
392 }
393
394 if (all_entries)
395 jit_relevant_entry = (addr_t)jit_entry.next_entry;
396 else
397 jit_relevant_entry = 0;
398 }
399
400 return false; // Continue Running.
401 }
402
403 // PluginInterface protocol
CreateInstance(Process * process,bool force)404 JITLoaderSP JITLoaderGDB::CreateInstance(Process *process, bool force) {
405 JITLoaderSP jit_loader_sp;
406 bool enable;
407 switch (GetGlobalPluginProperties().GetEnable()) {
408 case EnableJITLoaderGDB::eEnableJITLoaderGDBOn:
409 enable = true;
410 break;
411 case EnableJITLoaderGDB::eEnableJITLoaderGDBOff:
412 enable = false;
413 break;
414 case EnableJITLoaderGDB::eEnableJITLoaderGDBDefault:
415 ArchSpec arch(process->GetTarget().GetArchitecture());
416 enable = arch.GetTriple().getVendor() != llvm::Triple::Apple;
417 break;
418 }
419 if (enable)
420 jit_loader_sp = std::make_shared<JITLoaderGDB>(process);
421 return jit_loader_sp;
422 }
423
GetPluginDescriptionStatic()424 llvm::StringRef JITLoaderGDB::GetPluginDescriptionStatic() {
425 return "JIT loader plug-in that watches for JIT events using the GDB "
426 "interface.";
427 }
428
Initialize()429 void JITLoaderGDB::Initialize() {
430 PluginManager::RegisterPlugin(GetPluginNameStatic(),
431 GetPluginDescriptionStatic(), CreateInstance,
432 DebuggerInitialize);
433 }
434
Terminate()435 void JITLoaderGDB::Terminate() {
436 PluginManager::UnregisterPlugin(CreateInstance);
437 }
438
DidSetJITBreakpoint() const439 bool JITLoaderGDB::DidSetJITBreakpoint() const {
440 return LLDB_BREAK_ID_IS_VALID(m_jit_break_id);
441 }
442
GetSymbolAddress(ModuleList & module_list,ConstString name,SymbolType symbol_type) const443 addr_t JITLoaderGDB::GetSymbolAddress(ModuleList &module_list,
444 ConstString name,
445 SymbolType symbol_type) const {
446 SymbolContextList target_symbols;
447 Target &target = m_process->GetTarget();
448
449 module_list.FindSymbolsWithNameAndType(name, symbol_type, target_symbols);
450 if (target_symbols.IsEmpty())
451 return LLDB_INVALID_ADDRESS;
452
453 SymbolContext sym_ctx;
454 target_symbols.GetContextAtIndex(0, sym_ctx);
455
456 const Address jit_descriptor_addr = sym_ctx.symbol->GetAddress();
457 if (!jit_descriptor_addr.IsValid())
458 return LLDB_INVALID_ADDRESS;
459
460 const addr_t jit_addr = jit_descriptor_addr.GetLoadAddress(&target);
461 return jit_addr;
462 }
463