1//===-- ObjCLanguageRuntime.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#include "clang/AST/Type.h"
9
10#include "ObjCLanguageRuntime.h"
11
12#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
13#include "lldb/Core/Module.h"
14#include "lldb/Core/PluginManager.h"
15#include "lldb/Symbol/SymbolContext.h"
16#include "lldb/Symbol/SymbolFile.h"
17#include "lldb/Symbol/Type.h"
18#include "lldb/Symbol/TypeList.h"
19#include "lldb/Symbol/Variable.h"
20#include "lldb/Target/ABI.h"
21#include "lldb/Target/Target.h"
22#include "lldb/Utility/LLDBLog.h"
23#include "lldb/Utility/Log.h"
24#include "lldb/Utility/Timer.h"
25#include "lldb/ValueObject/ValueObject.h"
26
27#include "llvm/ADT/StringRef.h"
28#include "llvm/Support/DJB.h"
29#include <optional>
30
31using namespace lldb;
32using namespace lldb_private;
33
34char ObjCLanguageRuntime::ID = 0;
35
36// Destructor
37ObjCLanguageRuntime::~ObjCLanguageRuntime() = default;
38
39ObjCLanguageRuntime::ObjCLanguageRuntime(Process *process)
40 : LanguageRuntime(process), m_impl_cache(), m_impl_str_cache(),
41 m_has_new_literals_and_indexing(eLazyBoolCalculate),
42 m_isa_to_descriptor(), m_hash_to_isa_map(), m_type_size_cache(),
43 m_isa_to_descriptor_stop_id(UINT32_MAX), m_complete_class_cache(),
44 m_negative_complete_class_cache() {}
45
46bool ObjCLanguageRuntime::IsAllowedRuntimeValue(ConstString name) {
47 static ConstString g_self = ConstString("self");
48 static ConstString g_cmd = ConstString("_cmd");
49 return name == g_self || name == g_cmd;
50}
51
52bool ObjCLanguageRuntime::AddClass(ObjCISA isa,
53 const ClassDescriptorSP &descriptor_sp,
54 const char *class_name) {
55 if (isa != 0) {
56 m_isa_to_descriptor[isa] = descriptor_sp;
57 // class_name is assumed to be valid
58 m_hash_to_isa_map.insert(x: std::make_pair(x: llvm::djbHash(Buffer: class_name), y&: isa));
59 return true;
60 }
61 return false;
62}
63
64void ObjCLanguageRuntime::AddToMethodCache(lldb::addr_t class_addr,
65 lldb::addr_t selector,
66 lldb::addr_t impl_addr) {
67 Log *log = GetLog(mask: LLDBLog::Step);
68 if (log) {
69 LLDB_LOGF(log,
70 "Caching: class 0x%" PRIx64 " selector 0x%" PRIx64
71 " implementation 0x%" PRIx64 ".",
72 class_addr, selector, impl_addr);
73 }
74 m_impl_cache.insert(x: std::pair<ClassAndSel, lldb::addr_t>(
75 ClassAndSel(class_addr, selector), impl_addr));
76}
77
78void ObjCLanguageRuntime::AddToMethodCache(lldb::addr_t class_addr,
79 llvm::StringRef sel_str,
80 lldb::addr_t impl_addr) {
81 Log *log = GetLog(mask: LLDBLog::Step);
82
83 LLDB_LOG(log, "Caching: class {0} selector {1} implementation {2}.",
84 class_addr, sel_str, impl_addr);
85
86 m_impl_str_cache.insert(x: std::pair<ClassAndSelStr, lldb::addr_t>(
87 ClassAndSelStr(class_addr, sel_str), impl_addr));
88}
89
90lldb::addr_t ObjCLanguageRuntime::LookupInMethodCache(lldb::addr_t class_addr,
91 lldb::addr_t selector) {
92 MsgImplMap::iterator pos, end = m_impl_cache.end();
93 pos = m_impl_cache.find(x: ClassAndSel(class_addr, selector));
94 if (pos != end)
95 return (*pos).second;
96 return LLDB_INVALID_ADDRESS;
97}
98
99lldb::addr_t ObjCLanguageRuntime::LookupInMethodCache(lldb::addr_t class_addr,
100 llvm::StringRef sel_str) {
101 MsgImplStrMap::iterator pos, end = m_impl_str_cache.end();
102 pos = m_impl_str_cache.find(x: ClassAndSelStr(class_addr, sel_str));
103 if (pos != end)
104 return (*pos).second;
105 return LLDB_INVALID_ADDRESS;
106}
107
108lldb::TypeSP
109ObjCLanguageRuntime::LookupInCompleteClassCache(ConstString &name) {
110 CompleteClassMap::iterator complete_class_iter =
111 m_complete_class_cache.find(x: name);
112
113 if (complete_class_iter != m_complete_class_cache.end()) {
114 // Check the weak pointer to make sure the type hasn't been unloaded
115 TypeSP complete_type_sp(complete_class_iter->second.lock());
116
117 if (complete_type_sp)
118 return complete_type_sp;
119 else
120 m_complete_class_cache.erase(x: name);
121 }
122
123 if (m_negative_complete_class_cache.count(x: name) > 0)
124 return TypeSP();
125
126 const ModuleList &modules = m_process->GetTarget().GetImages();
127
128 SymbolContextList sc_list;
129 modules.FindSymbolsWithNameAndType(name, symbol_type: eSymbolTypeObjCClass, sc_list);
130 const size_t matching_symbols = sc_list.GetSize();
131
132 if (matching_symbols) {
133 SymbolContext sc;
134
135 sc_list.GetContextAtIndex(idx: 0, sc);
136
137 ModuleSP module_sp(sc.module_sp);
138
139 if (!module_sp)
140 return TypeSP();
141
142 TypeQuery query(name.GetStringRef(), TypeQueryOptions::e_exact_match);
143 TypeResults results;
144 module_sp->FindTypes(query, results);
145 for (const TypeSP &type_sp : results.GetTypeMap().Types()) {
146 if (TypeSystemClang::IsObjCObjectOrInterfaceType(
147 type: type_sp->GetForwardCompilerType())) {
148 if (TypePayloadClang(type_sp->GetPayload()).IsCompleteObjCClass()) {
149 m_complete_class_cache[name] = type_sp;
150 return type_sp;
151 }
152 }
153 }
154 }
155 m_negative_complete_class_cache.insert(x: name);
156 return TypeSP();
157}
158
159size_t ObjCLanguageRuntime::GetByteOffsetForIvar(CompilerType &parent_qual_type,
160 const char *ivar_name) {
161 return LLDB_INVALID_IVAR_OFFSET;
162}
163
164bool ObjCLanguageRuntime::ClassDescriptor::IsPointerValid(
165 lldb::addr_t value, uint32_t ptr_size, bool allow_NULLs, bool allow_tagged,
166 bool check_version_specific) const {
167 if (!value)
168 return allow_NULLs;
169 if ((value % 2) == 1 && allow_tagged)
170 return true;
171 if ((value % ptr_size) == 0)
172 return (check_version_specific ? CheckPointer(value, ptr_size) : true);
173 else
174 return false;
175}
176
177ObjCLanguageRuntime::ObjCISA
178ObjCLanguageRuntime::GetISA(ConstString name) {
179 ISAToDescriptorIterator pos = GetDescriptorIterator(name);
180 if (pos != m_isa_to_descriptor.end())
181 return pos->first;
182 return 0;
183}
184
185ObjCLanguageRuntime::ISAToDescriptorIterator
186ObjCLanguageRuntime::GetDescriptorIterator(ConstString name) {
187 ISAToDescriptorIterator end = m_isa_to_descriptor.end();
188
189 if (name) {
190 UpdateISAToDescriptorMap();
191 if (m_hash_to_isa_map.empty()) {
192 // No name hashes were provided, we need to just linearly power through
193 // the names and find a match
194 for (ISAToDescriptorIterator pos = m_isa_to_descriptor.begin();
195 pos != end; ++pos) {
196 if (pos->second->GetClassName() == name)
197 return pos;
198 }
199 } else {
200 // Name hashes were provided, so use them to efficiently lookup name to
201 // isa/descriptor
202 const uint32_t name_hash = llvm::djbHash(Buffer: name.GetStringRef());
203 std::pair<HashToISAIterator, HashToISAIterator> range =
204 m_hash_to_isa_map.equal_range(x: name_hash);
205 for (HashToISAIterator range_pos = range.first; range_pos != range.second;
206 ++range_pos) {
207 ISAToDescriptorIterator pos =
208 m_isa_to_descriptor.find(x: range_pos->second);
209 if (pos != m_isa_to_descriptor.end()) {
210 if (pos->second->GetClassName() == name)
211 return pos;
212 }
213 }
214 }
215 }
216 return end;
217}
218
219std::pair<ObjCLanguageRuntime::ISAToDescriptorIterator,
220 ObjCLanguageRuntime::ISAToDescriptorIterator>
221ObjCLanguageRuntime::GetDescriptorIteratorPair(bool update_if_needed) {
222 if (update_if_needed)
223 UpdateISAToDescriptorMapIfNeeded();
224
225 return std::pair<ObjCLanguageRuntime::ISAToDescriptorIterator,
226 ObjCLanguageRuntime::ISAToDescriptorIterator>(
227 m_isa_to_descriptor.begin(), m_isa_to_descriptor.end());
228}
229
230void ObjCLanguageRuntime::ReadObjCLibraryIfNeeded(
231 const ModuleList &module_list) {
232 if (!HasReadObjCLibrary()) {
233 std::lock_guard<std::recursive_mutex> guard(module_list.GetMutex());
234
235 size_t num_modules = module_list.GetSize();
236 for (size_t i = 0; i < num_modules; i++) {
237 auto mod = module_list.GetModuleAtIndex(idx: i);
238 if (IsModuleObjCLibrary(module_sp: mod)) {
239 ReadObjCLibrary(module_sp: mod);
240 break;
241 }
242 }
243 }
244}
245
246ObjCLanguageRuntime::ObjCISA
247ObjCLanguageRuntime::GetParentClass(ObjCLanguageRuntime::ObjCISA isa) {
248 ClassDescriptorSP objc_class_sp(GetClassDescriptorFromISA(isa));
249 if (objc_class_sp) {
250 ClassDescriptorSP objc_super_class_sp(objc_class_sp->GetSuperclass());
251 if (objc_super_class_sp)
252 return objc_super_class_sp->GetISA();
253 }
254 return 0;
255}
256
257ObjCLanguageRuntime::ClassDescriptorSP
258ObjCLanguageRuntime::GetClassDescriptorFromClassName(
259 ConstString class_name) {
260 ISAToDescriptorIterator pos = GetDescriptorIterator(name: class_name);
261 if (pos != m_isa_to_descriptor.end())
262 return pos->second;
263 return ClassDescriptorSP();
264}
265
266ObjCLanguageRuntime::ClassDescriptorSP
267ObjCLanguageRuntime::GetClassDescriptor(ValueObject &valobj) {
268 ClassDescriptorSP objc_class_sp;
269 // if we get an invalid VO (which might still happen when playing around with
270 // pointers returned by the expression parser, don't consider this a valid
271 // ObjC object)
272 if (valobj.GetCompilerType().IsValid()) {
273 addr_t isa_pointer = valobj.GetPointerValue().address;
274 if (isa_pointer != LLDB_INVALID_ADDRESS) {
275 ExecutionContext exe_ctx(valobj.GetExecutionContextRef());
276
277 Process *process = exe_ctx.GetProcessPtr();
278 if (process) {
279 Status error;
280 ObjCISA isa = process->ReadPointerFromMemory(vm_addr: isa_pointer, error);
281 if (isa != LLDB_INVALID_ADDRESS)
282 objc_class_sp = GetClassDescriptorFromISA(isa);
283 }
284 }
285 }
286 return objc_class_sp;
287}
288
289ObjCLanguageRuntime::ClassDescriptorSP
290ObjCLanguageRuntime::GetNonKVOClassDescriptor(ValueObject &valobj) {
291 ObjCLanguageRuntime::ClassDescriptorSP objc_class_sp(
292 GetClassDescriptor(valobj));
293 if (objc_class_sp) {
294 if (!objc_class_sp->IsKVO())
295 return objc_class_sp;
296
297 ClassDescriptorSP non_kvo_objc_class_sp(objc_class_sp->GetSuperclass());
298 if (non_kvo_objc_class_sp && non_kvo_objc_class_sp->IsValid())
299 return non_kvo_objc_class_sp;
300 }
301 return ClassDescriptorSP();
302}
303
304ObjCLanguageRuntime::ClassDescriptorSP
305ObjCLanguageRuntime::GetClassDescriptorFromISA(ObjCISA isa) {
306 if (isa) {
307 UpdateISAToDescriptorMap();
308
309 ObjCLanguageRuntime::ISAToDescriptorIterator pos =
310 m_isa_to_descriptor.find(x: isa);
311 if (pos != m_isa_to_descriptor.end())
312 return pos->second;
313
314 if (ABISP abi_sp = m_process->GetABI()) {
315 pos = m_isa_to_descriptor.find(x: abi_sp->FixCodeAddress(pc: isa));
316 if (pos != m_isa_to_descriptor.end())
317 return pos->second;
318 }
319 }
320 return ClassDescriptorSP();
321}
322
323ObjCLanguageRuntime::ClassDescriptorSP
324ObjCLanguageRuntime::GetNonKVOClassDescriptor(ObjCISA isa) {
325 if (isa) {
326 ClassDescriptorSP objc_class_sp = GetClassDescriptorFromISA(isa);
327 if (objc_class_sp && objc_class_sp->IsValid()) {
328 if (!objc_class_sp->IsKVO())
329 return objc_class_sp;
330
331 ClassDescriptorSP non_kvo_objc_class_sp(objc_class_sp->GetSuperclass());
332 if (non_kvo_objc_class_sp && non_kvo_objc_class_sp->IsValid())
333 return non_kvo_objc_class_sp;
334 }
335 }
336 return ClassDescriptorSP();
337}
338
339CompilerType
340ObjCLanguageRuntime::EncodingToType::RealizeType(const char *name,
341 bool for_expression) {
342 if (m_scratch_ast_ctx_sp)
343 return RealizeType(ast_ctx&: *m_scratch_ast_ctx_sp, name, for_expression);
344 return CompilerType();
345}
346
347ObjCLanguageRuntime::EncodingToType::~EncodingToType() = default;
348
349ObjCLanguageRuntime::EncodingToTypeSP ObjCLanguageRuntime::GetEncodingToType() {
350 return nullptr;
351}
352
353std::optional<uint64_t>
354ObjCLanguageRuntime::GetTypeBitSize(const CompilerType &compiler_type) {
355 void *opaque_ptr = compiler_type.GetOpaqueQualType();
356 uint64_t cached_size = m_type_size_cache.Lookup(k: opaque_ptr);
357 if (cached_size > 0)
358 return cached_size;
359
360 ClassDescriptorSP class_descriptor_sp =
361 GetClassDescriptorFromClassName(class_name: compiler_type.GetTypeName());
362 if (!class_descriptor_sp)
363 return {};
364
365 int32_t max_offset = INT32_MIN;
366 uint64_t sizeof_max = 0;
367 bool found = false;
368
369 for (size_t idx = 0; idx < class_descriptor_sp->GetNumIVars(); idx++) {
370 const auto &ivar = class_descriptor_sp->GetIVarAtIndex(idx);
371 int32_t cur_offset = ivar.m_offset;
372 if (cur_offset > max_offset) {
373 max_offset = cur_offset;
374 sizeof_max = ivar.m_size;
375 found = true;
376 }
377 }
378
379 uint64_t size = 8 * (max_offset + sizeof_max);
380 if (found && size > 0) {
381 m_type_size_cache.Insert(k: opaque_ptr, v: size);
382 return size;
383 }
384
385 return {};
386}
387
388lldb::BreakpointPreconditionSP
389ObjCLanguageRuntime::GetBreakpointExceptionPrecondition(LanguageType language,
390 bool throw_bp) {
391 if (language != eLanguageTypeObjC)
392 return lldb::BreakpointPreconditionSP();
393 if (!throw_bp)
394 return lldb::BreakpointPreconditionSP();
395 BreakpointPreconditionSP precondition_sp(
396 new ObjCLanguageRuntime::ObjCExceptionPrecondition());
397 return precondition_sp;
398}
399
400// Exception breakpoint Precondition class for ObjC:
401void ObjCLanguageRuntime::ObjCExceptionPrecondition::AddClassName(
402 const char *class_name) {
403 m_class_names.insert(x: class_name);
404}
405
406ObjCLanguageRuntime::ObjCExceptionPrecondition::ObjCExceptionPrecondition() =
407 default;
408
409bool ObjCLanguageRuntime::ObjCExceptionPrecondition::EvaluatePrecondition(
410 StoppointCallbackContext &context) {
411 return true;
412}
413
414void ObjCLanguageRuntime::ObjCExceptionPrecondition::GetDescription(
415 Stream &stream, lldb::DescriptionLevel level) {}
416
417Status ObjCLanguageRuntime::ObjCExceptionPrecondition::ConfigurePrecondition(
418 Args &args) {
419 Status error;
420 if (args.GetArgumentCount() > 0)
421 error = Status::FromErrorString(
422 str: "The ObjC Exception breakpoint doesn't support extra options.");
423 return error;
424}
425
426std::optional<CompilerType>
427ObjCLanguageRuntime::GetRuntimeType(CompilerType base_type) {
428 CompilerType class_type;
429 bool is_pointer_type = false;
430
431 if (TypeSystemClang::IsObjCObjectPointerType(type: base_type, target_type: &class_type))
432 is_pointer_type = true;
433 else if (TypeSystemClang::IsObjCObjectOrInterfaceType(type: base_type))
434 class_type = base_type;
435 else
436 return std::nullopt;
437
438 if (!class_type)
439 return std::nullopt;
440
441 ConstString class_name(class_type.GetTypeName());
442 if (!class_name)
443 return std::nullopt;
444
445 TypeSP complete_objc_class_type_sp = LookupInCompleteClassCache(name&: class_name);
446 if (!complete_objc_class_type_sp)
447 return std::nullopt;
448
449 CompilerType complete_class(
450 complete_objc_class_type_sp->GetFullCompilerType());
451 if (complete_class.GetCompleteType()) {
452 if (is_pointer_type)
453 return complete_class.GetPointerType();
454 else
455 return complete_class;
456 }
457
458 return std::nullopt;
459}
460

source code of lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.cpp