1 //===-- LanguageRuntime.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 
9 #include "lldb/Target/LanguageRuntime.h"
10 #include "lldb/Core/PluginManager.h"
11 #include "lldb/Core/SearchFilter.h"
12 #include "lldb/Interpreter/CommandInterpreter.h"
13 #include "lldb/Target/Language.h"
14 #include "lldb/Target/Target.h"
15 
16 using namespace lldb;
17 using namespace lldb_private;
18 
19 char LanguageRuntime::ID = 0;
20 
21 ExceptionSearchFilter::ExceptionSearchFilter(const lldb::TargetSP &target_sp,
22                                              lldb::LanguageType language,
23                                              bool update_module_list)
24     : SearchFilter(target_sp, FilterTy::Exception), m_language(language),
25       m_language_runtime(nullptr), m_filter_sp() {
26   if (update_module_list)
27     UpdateModuleListIfNeeded();
28 }
29 
30 bool ExceptionSearchFilter::ModulePasses(const lldb::ModuleSP &module_sp) {
31   UpdateModuleListIfNeeded();
32   if (m_filter_sp)
33     return m_filter_sp->ModulePasses(module_sp);
34   return false;
35 }
36 
37 bool ExceptionSearchFilter::ModulePasses(const FileSpec &spec) {
38   UpdateModuleListIfNeeded();
39   if (m_filter_sp)
40     return m_filter_sp->ModulePasses(spec);
41   return false;
42 }
43 
44 void ExceptionSearchFilter::Search(Searcher &searcher) {
45   UpdateModuleListIfNeeded();
46   if (m_filter_sp)
47     m_filter_sp->Search(searcher);
48 }
49 
50 void ExceptionSearchFilter::GetDescription(Stream *s) {
51   UpdateModuleListIfNeeded();
52   if (m_filter_sp)
53     m_filter_sp->GetDescription(s);
54 }
55 
56 void ExceptionSearchFilter::UpdateModuleListIfNeeded() {
57   ProcessSP process_sp(m_target_sp->GetProcessSP());
58   if (process_sp) {
59     bool refreash_filter = !m_filter_sp;
60     if (m_language_runtime == nullptr) {
61       m_language_runtime = process_sp->GetLanguageRuntime(m_language);
62       refreash_filter = true;
63     } else {
64       LanguageRuntime *language_runtime =
65           process_sp->GetLanguageRuntime(m_language);
66       if (m_language_runtime != language_runtime) {
67         m_language_runtime = language_runtime;
68         refreash_filter = true;
69       }
70     }
71 
72     if (refreash_filter && m_language_runtime) {
73       m_filter_sp = m_language_runtime->CreateExceptionSearchFilter();
74     }
75   } else {
76     m_filter_sp.reset();
77     m_language_runtime = nullptr;
78   }
79 }
80 
81 SearchFilterSP
82 ExceptionSearchFilter::DoCopyForBreakpoint(Breakpoint &breakpoint) {
83   return SearchFilterSP(
84       new ExceptionSearchFilter(TargetSP(), m_language, false));
85 }
86 
87 SearchFilter *ExceptionSearchFilter::CreateFromStructuredData(
88     Target &target, const StructuredData::Dictionary &data_dict,
89     Status &error) {
90   SearchFilter *result = nullptr;
91   return result;
92 }
93 
94 StructuredData::ObjectSP ExceptionSearchFilter::SerializeToStructuredData() {
95   StructuredData::ObjectSP result_sp;
96 
97   return result_sp;
98 }
99 
100 // The Target is the one that knows how to create breakpoints, so this function
101 // is meant to be used either by the target or internally in
102 // Set/ClearExceptionBreakpoints.
103 class ExceptionBreakpointResolver : public BreakpointResolver {
104 public:
105   ExceptionBreakpointResolver(lldb::LanguageType language, bool catch_bp,
106                               bool throw_bp)
107       : BreakpointResolver(nullptr, BreakpointResolver::ExceptionResolver),
108         m_language(language), m_language_runtime(nullptr), m_catch_bp(catch_bp),
109         m_throw_bp(throw_bp) {}
110 
111   ~ExceptionBreakpointResolver() override = default;
112 
113   Searcher::CallbackReturn SearchCallback(SearchFilter &filter,
114                                           SymbolContext &context,
115                                           Address *addr) override {
116 
117     if (SetActualResolver())
118       return m_actual_resolver_sp->SearchCallback(filter, context, addr);
119     else
120       return eCallbackReturnStop;
121   }
122 
123   lldb::SearchDepth GetDepth() override {
124     if (SetActualResolver())
125       return m_actual_resolver_sp->GetDepth();
126     else
127       return lldb::eSearchDepthTarget;
128   }
129 
130   void GetDescription(Stream *s) override {
131     Language *language_plugin = Language::FindPlugin(m_language);
132     if (language_plugin)
133       language_plugin->GetExceptionResolverDescription(m_catch_bp, m_throw_bp,
134                                                        *s);
135     else
136       Language::GetDefaultExceptionResolverDescription(m_catch_bp, m_throw_bp,
137                                                        *s);
138 
139     SetActualResolver();
140     if (m_actual_resolver_sp) {
141       s->Printf(" using: ");
142       m_actual_resolver_sp->GetDescription(s);
143     } else
144       s->Printf(" the correct runtime exception handler will be determined "
145                 "when you run");
146   }
147 
148   void Dump(Stream *s) const override {}
149 
150   /// Methods for support type inquiry through isa, cast, and dyn_cast:
151   static inline bool classof(const BreakpointResolverName *) { return true; }
152   static inline bool classof(const BreakpointResolver *V) {
153     return V->getResolverID() == BreakpointResolver::ExceptionResolver;
154   }
155 
156 protected:
157   BreakpointResolverSP CopyForBreakpoint(Breakpoint &breakpoint) override {
158     return BreakpointResolverSP(
159         new ExceptionBreakpointResolver(m_language, m_catch_bp, m_throw_bp));
160   }
161 
162   bool SetActualResolver() {
163     ProcessSP process_sp;
164     if (m_breakpoint) {
165       process_sp = m_breakpoint->GetTarget().GetProcessSP();
166       if (process_sp) {
167         bool refreash_resolver = !m_actual_resolver_sp;
168         if (m_language_runtime == nullptr) {
169           m_language_runtime = process_sp->GetLanguageRuntime(m_language);
170           refreash_resolver = true;
171         } else {
172           LanguageRuntime *language_runtime =
173               process_sp->GetLanguageRuntime(m_language);
174           if (m_language_runtime != language_runtime) {
175             m_language_runtime = language_runtime;
176             refreash_resolver = true;
177           }
178         }
179 
180         if (refreash_resolver && m_language_runtime) {
181           m_actual_resolver_sp = m_language_runtime->CreateExceptionResolver(
182               m_breakpoint, m_catch_bp, m_throw_bp);
183         }
184       } else {
185         m_actual_resolver_sp.reset();
186         m_language_runtime = nullptr;
187       }
188     } else {
189       m_actual_resolver_sp.reset();
190       m_language_runtime = nullptr;
191     }
192     return (bool)m_actual_resolver_sp;
193   }
194 
195   lldb::BreakpointResolverSP m_actual_resolver_sp;
196   lldb::LanguageType m_language;
197   LanguageRuntime *m_language_runtime;
198   bool m_catch_bp;
199   bool m_throw_bp;
200 };
201 
202 LanguageRuntime *LanguageRuntime::FindPlugin(Process *process,
203                                              lldb::LanguageType language) {
204   std::unique_ptr<LanguageRuntime> language_runtime_up;
205   LanguageRuntimeCreateInstance create_callback;
206 
207   for (uint32_t idx = 0;
208        (create_callback =
209             PluginManager::GetLanguageRuntimeCreateCallbackAtIndex(idx)) !=
210        nullptr;
211        ++idx) {
212     language_runtime_up.reset(create_callback(process, language));
213 
214     if (language_runtime_up)
215       return language_runtime_up.release();
216   }
217 
218   return nullptr;
219 }
220 
221 LanguageRuntime::LanguageRuntime(Process *process) : m_process(process) {}
222 
223 LanguageRuntime::~LanguageRuntime() = default;
224 
225 BreakpointPreconditionSP
226 LanguageRuntime::GetExceptionPrecondition(LanguageType language,
227                                           bool throw_bp) {
228   LanguageRuntimeCreateInstance create_callback;
229   for (uint32_t idx = 0;
230        (create_callback =
231             PluginManager::GetLanguageRuntimeCreateCallbackAtIndex(idx)) !=
232        nullptr;
233        idx++) {
234     if (auto precondition_callback =
235             PluginManager::GetLanguageRuntimeGetExceptionPreconditionAtIndex(
236                 idx)) {
237       if (BreakpointPreconditionSP precond =
238               precondition_callback(language, throw_bp))
239         return precond;
240     }
241   }
242   return BreakpointPreconditionSP();
243 }
244 
245 BreakpointSP LanguageRuntime::CreateExceptionBreakpoint(
246     Target &target, lldb::LanguageType language, bool catch_bp, bool throw_bp,
247     bool is_internal) {
248   BreakpointResolverSP resolver_sp(
249       new ExceptionBreakpointResolver(language, catch_bp, throw_bp));
250   SearchFilterSP filter_sp(
251       new ExceptionSearchFilter(target.shared_from_this(), language));
252   bool hardware = false;
253   bool resolve_indirect_functions = false;
254   BreakpointSP exc_breakpt_sp(
255       target.CreateBreakpoint(filter_sp, resolver_sp, is_internal, hardware,
256                               resolve_indirect_functions));
257   if (exc_breakpt_sp) {
258     if (auto precond = GetExceptionPrecondition(language, throw_bp))
259       exc_breakpt_sp->SetPrecondition(precond);
260 
261     if (is_internal)
262       exc_breakpt_sp->SetBreakpointKind("exception");
263   }
264 
265   return exc_breakpt_sp;
266 }
267 
268 void LanguageRuntime::InitializeCommands(CommandObject *parent) {
269   if (!parent)
270     return;
271 
272   if (!parent->IsMultiwordObject())
273     return;
274 
275   LanguageRuntimeCreateInstance create_callback;
276 
277   for (uint32_t idx = 0;
278        (create_callback =
279             PluginManager::GetLanguageRuntimeCreateCallbackAtIndex(idx)) !=
280        nullptr;
281        ++idx) {
282     if (LanguageRuntimeGetCommandObject command_callback =
283             PluginManager::GetLanguageRuntimeGetCommandObjectAtIndex(idx)) {
284       CommandObjectSP command =
285           command_callback(parent->GetCommandInterpreter());
286       if (command) {
287         // the CommandObject vended by a Language plugin cannot be created once
288         // and cached because we may create multiple debuggers and need one
289         // instance of the command each - the implementing function is meant to
290         // create a new instance of the command each time it is invoked.
291         parent->LoadSubCommand(command->GetCommandName().str().c_str(), command);
292       }
293     }
294   }
295 }
296