xref: /freebsd-src/contrib/llvm-project/lldb/source/Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.cpp (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1 //===-- ObjCLanguageRuntime.cpp ---------------------------------*- C++ -*-===//
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 "lldb/Core/MappedHash.h"
13 #include "lldb/Core/Module.h"
14 #include "lldb/Core/PluginManager.h"
15 #include "lldb/Core/ValueObject.h"
16 #include "lldb/Symbol/ClangASTContext.h"
17 #include "lldb/Symbol/SymbolContext.h"
18 #include "lldb/Symbol/SymbolFile.h"
19 #include "lldb/Symbol/Type.h"
20 #include "lldb/Symbol/TypeList.h"
21 #include "lldb/Symbol/Variable.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Utility/Log.h"
24 #include "lldb/Utility/Timer.h"
25 
26 #include "llvm/ADT/StringRef.h"
27 #include "llvm/Support/DJB.h"
28 
29 using namespace lldb;
30 using namespace lldb_private;
31 
32 char ObjCLanguageRuntime::ID = 0;
33 
34 // Destructor
35 ObjCLanguageRuntime::~ObjCLanguageRuntime() {}
36 
37 ObjCLanguageRuntime::ObjCLanguageRuntime(Process *process)
38     : LanguageRuntime(process), m_impl_cache(),
39       m_has_new_literals_and_indexing(eLazyBoolCalculate),
40       m_isa_to_descriptor(), m_hash_to_isa_map(), m_type_size_cache(),
41       m_isa_to_descriptor_stop_id(UINT32_MAX), m_complete_class_cache(),
42       m_negative_complete_class_cache() {}
43 
44 bool ObjCLanguageRuntime::IsWhitelistedRuntimeValue(ConstString name) {
45   static ConstString g_self = ConstString("self");
46   static ConstString g_cmd = ConstString("_cmd");
47   return name == g_self || name == g_cmd;
48 }
49 
50 bool ObjCLanguageRuntime::AddClass(ObjCISA isa,
51                                    const ClassDescriptorSP &descriptor_sp,
52                                    const char *class_name) {
53   if (isa != 0) {
54     m_isa_to_descriptor[isa] = descriptor_sp;
55     // class_name is assumed to be valid
56     m_hash_to_isa_map.insert(std::make_pair(llvm::djbHash(class_name), isa));
57     return true;
58   }
59   return false;
60 }
61 
62 void ObjCLanguageRuntime::AddToMethodCache(lldb::addr_t class_addr,
63                                            lldb::addr_t selector,
64                                            lldb::addr_t impl_addr) {
65   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
66   if (log) {
67     log->Printf("Caching: class 0x%" PRIx64 " selector 0x%" PRIx64
68                 " implementation 0x%" PRIx64 ".",
69                 class_addr, selector, impl_addr);
70   }
71   m_impl_cache.insert(std::pair<ClassAndSel, lldb::addr_t>(
72       ClassAndSel(class_addr, selector), impl_addr));
73 }
74 
75 lldb::addr_t ObjCLanguageRuntime::LookupInMethodCache(lldb::addr_t class_addr,
76                                                       lldb::addr_t selector) {
77   MsgImplMap::iterator pos, end = m_impl_cache.end();
78   pos = m_impl_cache.find(ClassAndSel(class_addr, selector));
79   if (pos != end)
80     return (*pos).second;
81   return LLDB_INVALID_ADDRESS;
82 }
83 
84 lldb::TypeSP
85 ObjCLanguageRuntime::LookupInCompleteClassCache(ConstString &name) {
86   CompleteClassMap::iterator complete_class_iter =
87       m_complete_class_cache.find(name);
88 
89   if (complete_class_iter != m_complete_class_cache.end()) {
90     // Check the weak pointer to make sure the type hasn't been unloaded
91     TypeSP complete_type_sp(complete_class_iter->second.lock());
92 
93     if (complete_type_sp)
94       return complete_type_sp;
95     else
96       m_complete_class_cache.erase(name);
97   }
98 
99   if (m_negative_complete_class_cache.count(name) > 0)
100     return TypeSP();
101 
102   const ModuleList &modules = m_process->GetTarget().GetImages();
103 
104   SymbolContextList sc_list;
105   const size_t matching_symbols =
106       modules.FindSymbolsWithNameAndType(name, eSymbolTypeObjCClass, sc_list);
107 
108   if (matching_symbols) {
109     SymbolContext sc;
110 
111     sc_list.GetContextAtIndex(0, sc);
112 
113     ModuleSP module_sp(sc.module_sp);
114 
115     if (!module_sp)
116       return TypeSP();
117 
118     const bool exact_match = true;
119     const uint32_t max_matches = UINT32_MAX;
120     TypeList types;
121 
122     llvm::DenseSet<SymbolFile *> searched_symbol_files;
123     const uint32_t num_types = module_sp->FindTypes(
124         name, exact_match, max_matches, searched_symbol_files, types);
125 
126     if (num_types) {
127       uint32_t i;
128       for (i = 0; i < num_types; ++i) {
129         TypeSP type_sp(types.GetTypeAtIndex(i));
130 
131         if (ClangASTContext::IsObjCObjectOrInterfaceType(
132                 type_sp->GetForwardCompilerType())) {
133           if (type_sp->IsCompleteObjCClass()) {
134             m_complete_class_cache[name] = type_sp;
135             return type_sp;
136           }
137         }
138       }
139     }
140   }
141   m_negative_complete_class_cache.insert(name);
142   return TypeSP();
143 }
144 
145 size_t ObjCLanguageRuntime::GetByteOffsetForIvar(CompilerType &parent_qual_type,
146                                                  const char *ivar_name) {
147   return LLDB_INVALID_IVAR_OFFSET;
148 }
149 
150 bool ObjCLanguageRuntime::ClassDescriptor::IsPointerValid(
151     lldb::addr_t value, uint32_t ptr_size, bool allow_NULLs, bool allow_tagged,
152     bool check_version_specific) const {
153   if (!value)
154     return allow_NULLs;
155   if ((value % 2) == 1 && allow_tagged)
156     return true;
157   if ((value % ptr_size) == 0)
158     return (check_version_specific ? CheckPointer(value, ptr_size) : true);
159   else
160     return false;
161 }
162 
163 ObjCLanguageRuntime::ObjCISA
164 ObjCLanguageRuntime::GetISA(ConstString name) {
165   ISAToDescriptorIterator pos = GetDescriptorIterator(name);
166   if (pos != m_isa_to_descriptor.end())
167     return pos->first;
168   return 0;
169 }
170 
171 ObjCLanguageRuntime::ISAToDescriptorIterator
172 ObjCLanguageRuntime::GetDescriptorIterator(ConstString name) {
173   ISAToDescriptorIterator end = m_isa_to_descriptor.end();
174 
175   if (name) {
176     UpdateISAToDescriptorMap();
177     if (m_hash_to_isa_map.empty()) {
178       // No name hashes were provided, we need to just linearly power through
179       // the names and find a match
180       for (ISAToDescriptorIterator pos = m_isa_to_descriptor.begin();
181            pos != end; ++pos) {
182         if (pos->second->GetClassName() == name)
183           return pos;
184       }
185     } else {
186       // Name hashes were provided, so use them to efficiently lookup name to
187       // isa/descriptor
188       const uint32_t name_hash = llvm::djbHash(name.GetStringRef());
189       std::pair<HashToISAIterator, HashToISAIterator> range =
190           m_hash_to_isa_map.equal_range(name_hash);
191       for (HashToISAIterator range_pos = range.first; range_pos != range.second;
192            ++range_pos) {
193         ISAToDescriptorIterator pos =
194             m_isa_to_descriptor.find(range_pos->second);
195         if (pos != m_isa_to_descriptor.end()) {
196           if (pos->second->GetClassName() == name)
197             return pos;
198         }
199       }
200     }
201   }
202   return end;
203 }
204 
205 std::pair<ObjCLanguageRuntime::ISAToDescriptorIterator,
206           ObjCLanguageRuntime::ISAToDescriptorIterator>
207 ObjCLanguageRuntime::GetDescriptorIteratorPair(bool update_if_needed) {
208   if (update_if_needed)
209     UpdateISAToDescriptorMapIfNeeded();
210 
211   return std::pair<ObjCLanguageRuntime::ISAToDescriptorIterator,
212                    ObjCLanguageRuntime::ISAToDescriptorIterator>(
213       m_isa_to_descriptor.begin(), m_isa_to_descriptor.end());
214 }
215 
216 ObjCLanguageRuntime::ObjCISA
217 ObjCLanguageRuntime::GetParentClass(ObjCLanguageRuntime::ObjCISA isa) {
218   ClassDescriptorSP objc_class_sp(GetClassDescriptorFromISA(isa));
219   if (objc_class_sp) {
220     ClassDescriptorSP objc_super_class_sp(objc_class_sp->GetSuperclass());
221     if (objc_super_class_sp)
222       return objc_super_class_sp->GetISA();
223   }
224   return 0;
225 }
226 
227 ConstString
228 ObjCLanguageRuntime::GetActualTypeName(ObjCLanguageRuntime::ObjCISA isa) {
229   ClassDescriptorSP objc_class_sp(GetNonKVOClassDescriptor(isa));
230   if (objc_class_sp)
231     return objc_class_sp->GetClassName();
232   return ConstString();
233 }
234 
235 ObjCLanguageRuntime::ClassDescriptorSP
236 ObjCLanguageRuntime::GetClassDescriptorFromClassName(
237     ConstString class_name) {
238   ISAToDescriptorIterator pos = GetDescriptorIterator(class_name);
239   if (pos != m_isa_to_descriptor.end())
240     return pos->second;
241   return ClassDescriptorSP();
242 }
243 
244 ObjCLanguageRuntime::ClassDescriptorSP
245 ObjCLanguageRuntime::GetClassDescriptor(ValueObject &valobj) {
246   ClassDescriptorSP objc_class_sp;
247   // if we get an invalid VO (which might still happen when playing around with
248   // pointers returned by the expression parser, don't consider this a valid
249   // ObjC object)
250   if (valobj.GetCompilerType().IsValid()) {
251     addr_t isa_pointer = valobj.GetPointerValue();
252     if (isa_pointer != LLDB_INVALID_ADDRESS) {
253       ExecutionContext exe_ctx(valobj.GetExecutionContextRef());
254 
255       Process *process = exe_ctx.GetProcessPtr();
256       if (process) {
257         Status error;
258         ObjCISA isa = process->ReadPointerFromMemory(isa_pointer, error);
259         if (isa != LLDB_INVALID_ADDRESS)
260           objc_class_sp = GetClassDescriptorFromISA(isa);
261       }
262     }
263   }
264   return objc_class_sp;
265 }
266 
267 ObjCLanguageRuntime::ClassDescriptorSP
268 ObjCLanguageRuntime::GetNonKVOClassDescriptor(ValueObject &valobj) {
269   ObjCLanguageRuntime::ClassDescriptorSP objc_class_sp(
270       GetClassDescriptor(valobj));
271   if (objc_class_sp) {
272     if (!objc_class_sp->IsKVO())
273       return objc_class_sp;
274 
275     ClassDescriptorSP non_kvo_objc_class_sp(objc_class_sp->GetSuperclass());
276     if (non_kvo_objc_class_sp && non_kvo_objc_class_sp->IsValid())
277       return non_kvo_objc_class_sp;
278   }
279   return ClassDescriptorSP();
280 }
281 
282 ObjCLanguageRuntime::ClassDescriptorSP
283 ObjCLanguageRuntime::GetClassDescriptorFromISA(ObjCISA isa) {
284   if (isa) {
285     UpdateISAToDescriptorMap();
286     ObjCLanguageRuntime::ISAToDescriptorIterator pos =
287         m_isa_to_descriptor.find(isa);
288     if (pos != m_isa_to_descriptor.end())
289       return pos->second;
290   }
291   return ClassDescriptorSP();
292 }
293 
294 ObjCLanguageRuntime::ClassDescriptorSP
295 ObjCLanguageRuntime::GetNonKVOClassDescriptor(ObjCISA isa) {
296   if (isa) {
297     ClassDescriptorSP objc_class_sp = GetClassDescriptorFromISA(isa);
298     if (objc_class_sp && objc_class_sp->IsValid()) {
299       if (!objc_class_sp->IsKVO())
300         return objc_class_sp;
301 
302       ClassDescriptorSP non_kvo_objc_class_sp(objc_class_sp->GetSuperclass());
303       if (non_kvo_objc_class_sp && non_kvo_objc_class_sp->IsValid())
304         return non_kvo_objc_class_sp;
305     }
306   }
307   return ClassDescriptorSP();
308 }
309 
310 CompilerType
311 ObjCLanguageRuntime::EncodingToType::RealizeType(const char *name,
312                                                  bool for_expression) {
313   if (m_scratch_ast_ctx_up)
314     return RealizeType(*m_scratch_ast_ctx_up, name, for_expression);
315   return CompilerType();
316 }
317 
318 CompilerType ObjCLanguageRuntime::EncodingToType::RealizeType(
319     ClangASTContext &ast_ctx, const char *name, bool for_expression) {
320   clang::ASTContext *clang_ast = ast_ctx.getASTContext();
321   if (!clang_ast)
322     return CompilerType();
323   return RealizeType(*clang_ast, name, for_expression);
324 }
325 
326 ObjCLanguageRuntime::EncodingToType::~EncodingToType() {}
327 
328 ObjCLanguageRuntime::EncodingToTypeSP ObjCLanguageRuntime::GetEncodingToType() {
329   return nullptr;
330 }
331 
332 bool ObjCLanguageRuntime::GetTypeBitSize(const CompilerType &compiler_type,
333                                          uint64_t &size) {
334   void *opaque_ptr = compiler_type.GetOpaqueQualType();
335   size = m_type_size_cache.Lookup(opaque_ptr);
336   // an ObjC object will at least have an ISA, so 0 is definitely not OK
337   if (size > 0)
338     return true;
339 
340   ClassDescriptorSP class_descriptor_sp =
341       GetClassDescriptorFromClassName(compiler_type.GetTypeName());
342   if (!class_descriptor_sp)
343     return false;
344 
345   int32_t max_offset = INT32_MIN;
346   uint64_t sizeof_max = 0;
347   bool found = false;
348 
349   for (size_t idx = 0; idx < class_descriptor_sp->GetNumIVars(); idx++) {
350     const auto &ivar = class_descriptor_sp->GetIVarAtIndex(idx);
351     int32_t cur_offset = ivar.m_offset;
352     if (cur_offset > max_offset) {
353       max_offset = cur_offset;
354       sizeof_max = ivar.m_size;
355       found = true;
356     }
357   }
358 
359   size = 8 * (max_offset + sizeof_max);
360   if (found)
361     m_type_size_cache.Insert(opaque_ptr, size);
362 
363   return found;
364 }
365 
366 lldb::BreakpointPreconditionSP
367 ObjCLanguageRuntime::GetBreakpointExceptionPrecondition(LanguageType language,
368                                                         bool throw_bp) {
369   if (language != eLanguageTypeObjC)
370     return lldb::BreakpointPreconditionSP();
371   if (!throw_bp)
372     return lldb::BreakpointPreconditionSP();
373   BreakpointPreconditionSP precondition_sp(
374       new ObjCLanguageRuntime::ObjCExceptionPrecondition());
375   return precondition_sp;
376 }
377 
378 // Exception breakpoint Precondition class for ObjC:
379 void ObjCLanguageRuntime::ObjCExceptionPrecondition::AddClassName(
380     const char *class_name) {
381   m_class_names.insert(class_name);
382 }
383 
384 ObjCLanguageRuntime::ObjCExceptionPrecondition::ObjCExceptionPrecondition() {}
385 
386 bool ObjCLanguageRuntime::ObjCExceptionPrecondition::EvaluatePrecondition(
387     StoppointCallbackContext &context) {
388   return true;
389 }
390 
391 void ObjCLanguageRuntime::ObjCExceptionPrecondition::GetDescription(
392     Stream &stream, lldb::DescriptionLevel level) {}
393 
394 Status ObjCLanguageRuntime::ObjCExceptionPrecondition::ConfigurePrecondition(
395     Args &args) {
396   Status error;
397   if (args.GetArgumentCount() > 0)
398     error.SetErrorString(
399         "The ObjC Exception breakpoint doesn't support extra options.");
400   return error;
401 }
402 
403 llvm::Optional<CompilerType>
404 ObjCLanguageRuntime::GetRuntimeType(CompilerType base_type) {
405   CompilerType class_type;
406   bool is_pointer_type = false;
407 
408   if (ClangASTContext::IsObjCObjectPointerType(base_type, &class_type))
409     is_pointer_type = true;
410   else if (ClangASTContext::IsObjCObjectOrInterfaceType(base_type))
411     class_type = base_type;
412   else
413     return llvm::None;
414 
415   if (!class_type)
416     return llvm::None;
417 
418   ConstString class_name(class_type.GetConstTypeName());
419   if (!class_name)
420     return llvm::None;
421 
422   TypeSP complete_objc_class_type_sp = LookupInCompleteClassCache(class_name);
423   if (!complete_objc_class_type_sp)
424     return llvm::None;
425 
426   CompilerType complete_class(
427       complete_objc_class_type_sp->GetFullCompilerType());
428   if (complete_class.GetCompleteType()) {
429     if (is_pointer_type)
430       return complete_class.GetPointerType();
431     else
432       return complete_class;
433   }
434 
435   return llvm::None;
436 }
437