1 //===-- LanguageRuntime.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 "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 ExceptionSearchFilter::DoCreateCopy() {
82   return SearchFilterSP(
83       new ExceptionSearchFilter(TargetSP(), m_language, false));
84 }
85 
86 SearchFilter *ExceptionSearchFilter::CreateFromStructuredData(
87     Target &target, const StructuredData::Dictionary &data_dict,
88     Status &error) {
89   SearchFilter *result = nullptr;
90   return result;
91 }
92 
93 StructuredData::ObjectSP ExceptionSearchFilter::SerializeToStructuredData() {
94   StructuredData::ObjectSP result_sp;
95 
96   return result_sp;
97 }
98 
99 // The Target is the one that knows how to create breakpoints, so this function
100 // is meant to be used either by the target or internally in
101 // Set/ClearExceptionBreakpoints.
102 class ExceptionBreakpointResolver : public BreakpointResolver {
103 public:
104   ExceptionBreakpointResolver(lldb::LanguageType language, bool catch_bp,
105                               bool throw_bp)
106       : BreakpointResolver(nullptr, BreakpointResolver::ExceptionResolver),
107         m_language(language), m_catch_bp(catch_bp), m_throw_bp(throw_bp) {}
108 
109   ~ExceptionBreakpointResolver() override = default;
110 
111   Searcher::CallbackReturn SearchCallback(SearchFilter &filter,
112                                           SymbolContext &context,
113                                           Address *addr) override {
114 
115     if (SetActualResolver())
116       return m_actual_resolver_sp->SearchCallback(filter, context, addr);
117     else
118       return eCallbackReturnStop;
119   }
120 
121   lldb::SearchDepth GetDepth() override {
122     if (SetActualResolver())
123       return m_actual_resolver_sp->GetDepth();
124     else
125       return lldb::eSearchDepthTarget;
126   }
127 
128   void GetDescription(Stream *s) override {
129     Language *language_plugin = Language::FindPlugin(m_language);
130     if (language_plugin)
131       language_plugin->GetExceptionResolverDescription(m_catch_bp, m_throw_bp,
132                                                        *s);
133     else
134       Language::GetDefaultExceptionResolverDescription(m_catch_bp, m_throw_bp,
135                                                        *s);
136 
137     SetActualResolver();
138     if (m_actual_resolver_sp) {
139       s->Printf(" using: ");
140       m_actual_resolver_sp->GetDescription(s);
141     } else
142       s->Printf(" the correct runtime exception handler will be determined "
143                 "when you run");
144   }
145 
146   void Dump(Stream *s) const override {}
147 
148   /// Methods for support type inquiry through isa, cast, and dyn_cast:
149   static inline bool classof(const BreakpointResolverName *) { return true; }
150   static inline bool classof(const BreakpointResolver *V) {
151     return V->getResolverID() == BreakpointResolver::ExceptionResolver;
152   }
153 
154 protected:
155   BreakpointResolverSP CopyForBreakpoint(BreakpointSP &breakpoint) override {
156     BreakpointResolverSP ret_sp(
157         new ExceptionBreakpointResolver(m_language, m_catch_bp, m_throw_bp));
158     ret_sp->SetBreakpoint(breakpoint);
159     return ret_sp;
160   }
161 
162   bool SetActualResolver() {
163     BreakpointSP breakpoint_sp = GetBreakpoint();
164     if (breakpoint_sp) {
165       ProcessSP process_sp = breakpoint_sp->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               breakpoint_sp, 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 = nullptr;
198   bool m_catch_bp;
199   bool m_throw_bp;
200 };
201 
202 LanguageRuntime *LanguageRuntime::FindPlugin(Process *process,
203                                              lldb::LanguageType language) {
204   LanguageRuntimeCreateInstance create_callback;
205   for (uint32_t idx = 0;
206        (create_callback =
207             PluginManager::GetLanguageRuntimeCreateCallbackAtIndex(idx)) !=
208        nullptr;
209        ++idx) {
210     if (LanguageRuntime *runtime = create_callback(process, language))
211       return runtime;
212   }
213   return nullptr;
214 }
215 
216 LanguageRuntime::LanguageRuntime(Process *process) : Runtime(process) {}
217 
218 BreakpointPreconditionSP
219 LanguageRuntime::GetExceptionPrecondition(LanguageType language,
220                                           bool throw_bp) {
221   LanguageRuntimeCreateInstance create_callback;
222   for (uint32_t idx = 0;
223        (create_callback =
224             PluginManager::GetLanguageRuntimeCreateCallbackAtIndex(idx)) !=
225        nullptr;
226        idx++) {
227     if (auto precondition_callback =
228             PluginManager::GetLanguageRuntimeGetExceptionPreconditionAtIndex(
229                 idx)) {
230       if (BreakpointPreconditionSP precond =
231               precondition_callback(language, throw_bp))
232         return precond;
233     }
234   }
235   return BreakpointPreconditionSP();
236 }
237 
238 BreakpointSP LanguageRuntime::CreateExceptionBreakpoint(
239     Target &target, lldb::LanguageType language, bool catch_bp, bool throw_bp,
240     bool is_internal) {
241   BreakpointResolverSP resolver_sp(
242       new ExceptionBreakpointResolver(language, catch_bp, throw_bp));
243   SearchFilterSP filter_sp(
244       new ExceptionSearchFilter(target.shared_from_this(), language));
245   bool hardware = false;
246   bool resolve_indirect_functions = false;
247   BreakpointSP exc_breakpt_sp(
248       target.CreateBreakpoint(filter_sp, resolver_sp, is_internal, hardware,
249                               resolve_indirect_functions));
250   if (exc_breakpt_sp) {
251     if (auto precond = GetExceptionPrecondition(language, throw_bp))
252       exc_breakpt_sp->SetPrecondition(precond);
253 
254     if (is_internal)
255       exc_breakpt_sp->SetBreakpointKind("exception");
256   }
257 
258   return exc_breakpt_sp;
259 }
260 
261 UnwindPlanSP
262 LanguageRuntime::GetRuntimeUnwindPlan(Thread &thread, RegisterContext *regctx,
263                                       bool &behaves_like_zeroth_frame) {
264   ProcessSP process_sp = thread.GetProcess();
265   if (!process_sp.get())
266     return UnwindPlanSP();
267   if (process_sp->GetDisableLangRuntimeUnwindPlans() == true)
268     return UnwindPlanSP();
269   for (const lldb::LanguageType lang_type : Language::GetSupportedLanguages()) {
270     if (LanguageRuntime *runtime = process_sp->GetLanguageRuntime(lang_type)) {
271       UnwindPlanSP plan_sp = runtime->GetRuntimeUnwindPlan(
272           process_sp, regctx, behaves_like_zeroth_frame);
273       if (plan_sp.get())
274         return plan_sp;
275     }
276   }
277   return UnwindPlanSP();
278 }
279 
280 void LanguageRuntime::InitializeCommands(CommandObject *parent) {
281   if (!parent)
282     return;
283 
284   if (!parent->IsMultiwordObject())
285     return;
286 
287   LanguageRuntimeCreateInstance create_callback;
288 
289   for (uint32_t idx = 0;
290        (create_callback =
291             PluginManager::GetLanguageRuntimeCreateCallbackAtIndex(idx)) !=
292        nullptr;
293        ++idx) {
294     if (LanguageRuntimeGetCommandObject command_callback =
295             PluginManager::GetLanguageRuntimeGetCommandObjectAtIndex(idx)) {
296       CommandObjectSP command =
297           command_callback(parent->GetCommandInterpreter());
298       if (command) {
299         // the CommandObject vended by a Language plugin cannot be created once
300         // and cached because we may create multiple debuggers and need one
301         // instance of the command each - the implementing function is meant to
302         // create a new instance of the command each time it is invoked.
303         parent->LoadSubCommand(command->GetCommandName().str().c_str(), command);
304       }
305     }
306   }
307 }
308