1 //===-- ClangUserExpression.cpp ---------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include <stdio.h>
11 #if HAVE_SYS_TYPES_H
12 #include <sys/types.h>
13 #endif
14 
15 #include <cstdlib>
16 #include <map>
17 #include <string>
18 
19 #include "ClangUserExpression.h"
20 
21 #include "ASTResultSynthesizer.h"
22 #include "ClangDiagnostic.h"
23 #include "ClangExpressionDeclMap.h"
24 #include "ClangExpressionParser.h"
25 #include "ClangModulesDeclVendor.h"
26 #include "ClangPersistentVariables.h"
27 
28 #include "lldb/Core/Debugger.h"
29 #include "lldb/Core/Module.h"
30 #include "lldb/Core/StreamFile.h"
31 #include "lldb/Core/ValueObjectConstResult.h"
32 #include "lldb/Expression/ExpressionSourceCode.h"
33 #include "lldb/Expression/IRExecutionUnit.h"
34 #include "lldb/Expression/IRInterpreter.h"
35 #include "lldb/Expression/Materializer.h"
36 #include "lldb/Host/HostInfo.h"
37 #include "lldb/Symbol/Block.h"
38 #include "lldb/Symbol/ClangASTContext.h"
39 #include "lldb/Symbol/ClangExternalASTSourceCommon.h"
40 #include "lldb/Symbol/Function.h"
41 #include "lldb/Symbol/ObjectFile.h"
42 #include "lldb/Symbol/SymbolVendor.h"
43 #include "lldb/Symbol/Type.h"
44 #include "lldb/Symbol/VariableList.h"
45 #include "lldb/Target/ExecutionContext.h"
46 #include "lldb/Target/Process.h"
47 #include "lldb/Target/StackFrame.h"
48 #include "lldb/Target/Target.h"
49 #include "lldb/Target/ThreadPlan.h"
50 #include "lldb/Target/ThreadPlanCallUserExpression.h"
51 #include "lldb/Utility/ConstString.h"
52 #include "lldb/Utility/Log.h"
53 #include "lldb/Utility/StreamString.h"
54 
55 #include "clang/AST/DeclCXX.h"
56 #include "clang/AST/DeclObjC.h"
57 
58 using namespace lldb_private;
59 
60 ClangUserExpression::ClangUserExpression(
61     ExecutionContextScope &exe_scope, llvm::StringRef expr,
62     llvm::StringRef prefix, lldb::LanguageType language,
63     ResultType desired_type, const EvaluateExpressionOptions &options)
64     : LLVMUserExpression(exe_scope, expr, prefix, language, desired_type,
65                          options),
66       m_type_system_helper(*m_target_wp.lock().get(),
67                            options.GetExecutionPolicy() ==
68                                eExecutionPolicyTopLevel),
69       m_result_delegate(exe_scope.CalculateTarget()) {
70   switch (m_language) {
71   case lldb::eLanguageTypeC_plus_plus:
72     m_allow_cxx = true;
73     break;
74   case lldb::eLanguageTypeObjC:
75     m_allow_objc = true;
76     break;
77   case lldb::eLanguageTypeObjC_plus_plus:
78   default:
79     m_allow_cxx = true;
80     m_allow_objc = true;
81     break;
82   }
83 }
84 
85 ClangUserExpression::~ClangUserExpression() {}
86 
87 void ClangUserExpression::ScanContext(ExecutionContext &exe_ctx, Status &err) {
88   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
89 
90   if (log)
91     log->Printf("ClangUserExpression::ScanContext()");
92 
93   m_target = exe_ctx.GetTargetPtr();
94 
95   if (!(m_allow_cxx || m_allow_objc)) {
96     if (log)
97       log->Printf("  [CUE::SC] Settings inhibit C++ and Objective-C");
98     return;
99   }
100 
101   StackFrame *frame = exe_ctx.GetFramePtr();
102   if (frame == NULL) {
103     if (log)
104       log->Printf("  [CUE::SC] Null stack frame");
105     return;
106   }
107 
108   SymbolContext sym_ctx = frame->GetSymbolContext(lldb::eSymbolContextFunction |
109                                                   lldb::eSymbolContextBlock);
110 
111   if (!sym_ctx.function) {
112     if (log)
113       log->Printf("  [CUE::SC] Null function");
114     return;
115   }
116 
117   // Find the block that defines the function represented by "sym_ctx"
118   Block *function_block = sym_ctx.GetFunctionBlock();
119 
120   if (!function_block) {
121     if (log)
122       log->Printf("  [CUE::SC] Null function block");
123     return;
124   }
125 
126   CompilerDeclContext decl_context = function_block->GetDeclContext();
127 
128   if (!decl_context) {
129     if (log)
130       log->Printf("  [CUE::SC] Null decl context");
131     return;
132   }
133 
134   if (clang::CXXMethodDecl *method_decl =
135           ClangASTContext::DeclContextGetAsCXXMethodDecl(decl_context)) {
136     if (m_allow_cxx && method_decl->isInstance()) {
137       if (m_enforce_valid_object) {
138         lldb::VariableListSP variable_list_sp(
139             function_block->GetBlockVariableList(true));
140 
141         const char *thisErrorString = "Stopped in a C++ method, but 'this' "
142                                       "isn't available; pretending we are in a "
143                                       "generic context";
144 
145         if (!variable_list_sp) {
146           err.SetErrorString(thisErrorString);
147           return;
148         }
149 
150         lldb::VariableSP this_var_sp(
151             variable_list_sp->FindVariable(ConstString("this")));
152 
153         if (!this_var_sp || !this_var_sp->IsInScope(frame) ||
154             !this_var_sp->LocationIsValidForFrame(frame)) {
155           err.SetErrorString(thisErrorString);
156           return;
157         }
158       }
159 
160       m_in_cplusplus_method = true;
161       m_needs_object_ptr = true;
162     }
163   } else if (clang::ObjCMethodDecl *method_decl =
164                  ClangASTContext::DeclContextGetAsObjCMethodDecl(
165                      decl_context)) {
166     if (m_allow_objc) {
167       if (m_enforce_valid_object) {
168         lldb::VariableListSP variable_list_sp(
169             function_block->GetBlockVariableList(true));
170 
171         const char *selfErrorString = "Stopped in an Objective-C method, but "
172                                       "'self' isn't available; pretending we "
173                                       "are in a generic context";
174 
175         if (!variable_list_sp) {
176           err.SetErrorString(selfErrorString);
177           return;
178         }
179 
180         lldb::VariableSP self_variable_sp =
181             variable_list_sp->FindVariable(ConstString("self"));
182 
183         if (!self_variable_sp || !self_variable_sp->IsInScope(frame) ||
184             !self_variable_sp->LocationIsValidForFrame(frame)) {
185           err.SetErrorString(selfErrorString);
186           return;
187         }
188       }
189 
190       m_in_objectivec_method = true;
191       m_needs_object_ptr = true;
192 
193       if (!method_decl->isInstanceMethod())
194         m_in_static_method = true;
195     }
196   } else if (clang::FunctionDecl *function_decl =
197                  ClangASTContext::DeclContextGetAsFunctionDecl(decl_context)) {
198     // We might also have a function that said in the debug information that it
199     // captured an object pointer.  The best way to deal with getting to the
200     // ivars at present is by pretending that this is a method of a class in
201     // whatever runtime the debug info says the object pointer belongs to.  Do
202     // that here.
203 
204     ClangASTMetadata *metadata =
205         ClangASTContext::DeclContextGetMetaData(decl_context, function_decl);
206     if (metadata && metadata->HasObjectPtr()) {
207       lldb::LanguageType language = metadata->GetObjectPtrLanguage();
208       if (language == lldb::eLanguageTypeC_plus_plus) {
209         if (m_enforce_valid_object) {
210           lldb::VariableListSP variable_list_sp(
211               function_block->GetBlockVariableList(true));
212 
213           const char *thisErrorString = "Stopped in a context claiming to "
214                                         "capture a C++ object pointer, but "
215                                         "'this' isn't available; pretending we "
216                                         "are in a generic context";
217 
218           if (!variable_list_sp) {
219             err.SetErrorString(thisErrorString);
220             return;
221           }
222 
223           lldb::VariableSP this_var_sp(
224               variable_list_sp->FindVariable(ConstString("this")));
225 
226           if (!this_var_sp || !this_var_sp->IsInScope(frame) ||
227               !this_var_sp->LocationIsValidForFrame(frame)) {
228             err.SetErrorString(thisErrorString);
229             return;
230           }
231         }
232 
233         m_in_cplusplus_method = true;
234         m_needs_object_ptr = true;
235       } else if (language == lldb::eLanguageTypeObjC) {
236         if (m_enforce_valid_object) {
237           lldb::VariableListSP variable_list_sp(
238               function_block->GetBlockVariableList(true));
239 
240           const char *selfErrorString =
241               "Stopped in a context claiming to capture an Objective-C object "
242               "pointer, but 'self' isn't available; pretending we are in a "
243               "generic context";
244 
245           if (!variable_list_sp) {
246             err.SetErrorString(selfErrorString);
247             return;
248           }
249 
250           lldb::VariableSP self_variable_sp =
251               variable_list_sp->FindVariable(ConstString("self"));
252 
253           if (!self_variable_sp || !self_variable_sp->IsInScope(frame) ||
254               !self_variable_sp->LocationIsValidForFrame(frame)) {
255             err.SetErrorString(selfErrorString);
256             return;
257           }
258 
259           Type *self_type = self_variable_sp->GetType();
260 
261           if (!self_type) {
262             err.SetErrorString(selfErrorString);
263             return;
264           }
265 
266           CompilerType self_clang_type = self_type->GetForwardCompilerType();
267 
268           if (!self_clang_type) {
269             err.SetErrorString(selfErrorString);
270             return;
271           }
272 
273           if (ClangASTContext::IsObjCClassType(self_clang_type)) {
274             return;
275           } else if (ClangASTContext::IsObjCObjectPointerType(
276                          self_clang_type)) {
277             m_in_objectivec_method = true;
278             m_needs_object_ptr = true;
279           } else {
280             err.SetErrorString(selfErrorString);
281             return;
282           }
283         } else {
284           m_in_objectivec_method = true;
285           m_needs_object_ptr = true;
286         }
287       }
288     }
289   }
290 }
291 
292 // This is a really nasty hack, meant to fix Objective-C expressions of the
293 // form (int)[myArray count].  Right now, because the type information for
294 // count is not available, [myArray count] returns id, which can't be directly
295 // cast to int without causing a clang error.
296 static void ApplyObjcCastHack(std::string &expr) {
297 #define OBJC_CAST_HACK_FROM "(int)["
298 #define OBJC_CAST_HACK_TO "(int)(long long)["
299 
300   size_t from_offset;
301 
302   while ((from_offset = expr.find(OBJC_CAST_HACK_FROM)) != expr.npos)
303     expr.replace(from_offset, sizeof(OBJC_CAST_HACK_FROM) - 1,
304                  OBJC_CAST_HACK_TO);
305 
306 #undef OBJC_CAST_HACK_TO
307 #undef OBJC_CAST_HACK_FROM
308 }
309 
310 namespace {
311 // Utility guard that calls a callback when going out of scope.
312 class OnExit {
313 public:
314   typedef std::function<void(void)> Callback;
315 
316   OnExit(Callback const &callback) : m_callback(callback) {}
317 
318   ~OnExit() { m_callback(); }
319 
320 private:
321   Callback m_callback;
322 };
323 } // namespace
324 
325 bool ClangUserExpression::SetupPersistentState(DiagnosticManager &diagnostic_manager,
326                                  ExecutionContext &exe_ctx) {
327   if (Target *target = exe_ctx.GetTargetPtr()) {
328     if (PersistentExpressionState *persistent_state =
329             target->GetPersistentExpressionStateForLanguage(
330                 lldb::eLanguageTypeC)) {
331       m_result_delegate.RegisterPersistentState(persistent_state);
332     } else {
333       diagnostic_manager.PutString(
334           eDiagnosticSeverityError,
335           "couldn't start parsing (no persistent data)");
336       return false;
337     }
338   } else {
339     diagnostic_manager.PutString(eDiagnosticSeverityError,
340                                  "error: couldn't start parsing (no target)");
341     return false;
342   }
343   return true;
344 }
345 
346 static void SetupDeclVendor(ExecutionContext &exe_ctx, Target *target) {
347   if (ClangModulesDeclVendor *decl_vendor =
348           target->GetClangModulesDeclVendor()) {
349     const ClangModulesDeclVendor::ModuleVector &hand_imported_modules =
350         llvm::cast<ClangPersistentVariables>(
351             target->GetPersistentExpressionStateForLanguage(
352                 lldb::eLanguageTypeC))
353             ->GetHandLoadedClangModules();
354     ClangModulesDeclVendor::ModuleVector modules_for_macros;
355 
356     for (ClangModulesDeclVendor::ModuleID module : hand_imported_modules) {
357       modules_for_macros.push_back(module);
358     }
359 
360     if (target->GetEnableAutoImportClangModules()) {
361       if (StackFrame *frame = exe_ctx.GetFramePtr()) {
362         if (Block *block = frame->GetFrameBlock()) {
363           SymbolContext sc;
364 
365           block->CalculateSymbolContext(&sc);
366 
367           if (sc.comp_unit) {
368             StreamString error_stream;
369 
370             decl_vendor->AddModulesForCompileUnit(
371                 *sc.comp_unit, modules_for_macros, error_stream);
372           }
373         }
374       }
375     }
376   }
377 }
378 
379 llvm::Optional<lldb::LanguageType> ClangUserExpression::GetLanguageForExpr(
380     DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx) {
381   lldb::LanguageType lang_type = lldb::LanguageType::eLanguageTypeUnknown;
382 
383   std::string prefix = m_expr_prefix;
384 
385   if (m_options.GetExecutionPolicy() == eExecutionPolicyTopLevel) {
386     m_transformed_text = m_expr_text;
387   } else {
388     std::unique_ptr<ExpressionSourceCode> source_code(
389         ExpressionSourceCode::CreateWrapped(prefix.c_str(),
390                                             m_expr_text.c_str()));
391 
392     if (m_in_cplusplus_method)
393       lang_type = lldb::eLanguageTypeC_plus_plus;
394     else if (m_in_objectivec_method)
395       lang_type = lldb::eLanguageTypeObjC;
396     else
397       lang_type = lldb::eLanguageTypeC;
398 
399     if (!source_code->GetText(m_transformed_text, lang_type, m_in_static_method,
400                               exe_ctx)) {
401       diagnostic_manager.PutString(eDiagnosticSeverityError,
402                                    "couldn't construct expression body");
403       return llvm::Optional<lldb::LanguageType>();
404     }
405   }
406   return lang_type;
407 }
408 
409 bool ClangUserExpression::PrepareForParsing(
410     DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx) {
411   InstallContext(exe_ctx);
412 
413   if (!SetupPersistentState(diagnostic_manager, exe_ctx))
414     return false;
415 
416   Status err;
417   ScanContext(exe_ctx, err);
418 
419   if (!err.Success()) {
420     diagnostic_manager.PutString(eDiagnosticSeverityWarning, err.AsCString());
421   }
422 
423   ////////////////////////////////////
424   // Generate the expression
425   //
426 
427   ApplyObjcCastHack(m_expr_text);
428 
429   SetupDeclVendor(exe_ctx, m_target);
430   return true;
431 }
432 
433 bool ClangUserExpression::Parse(DiagnosticManager &diagnostic_manager,
434                                 ExecutionContext &exe_ctx,
435                                 lldb_private::ExecutionPolicy execution_policy,
436                                 bool keep_result_in_memory,
437                                 bool generate_debug_info) {
438   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
439 
440   if (!PrepareForParsing(diagnostic_manager, exe_ctx))
441     return false;
442 
443   lldb::LanguageType lang_type = lldb::LanguageType::eLanguageTypeUnknown;
444   if (auto new_lang = GetLanguageForExpr(diagnostic_manager, exe_ctx)) {
445     lang_type = new_lang.getValue();
446   }
447 
448   if (log)
449     log->Printf("Parsing the following code:\n%s", m_transformed_text.c_str());
450 
451   ////////////////////////////////////
452   // Set up the target and compiler
453   //
454 
455   Target *target = exe_ctx.GetTargetPtr();
456 
457   if (!target) {
458     diagnostic_manager.PutString(eDiagnosticSeverityError, "invalid target");
459     return false;
460   }
461 
462   //////////////////////////
463   // Parse the expression
464   //
465 
466   m_materializer_ap.reset(new Materializer());
467 
468   ResetDeclMap(exe_ctx, m_result_delegate, keep_result_in_memory);
469 
470   OnExit on_exit([this]() { ResetDeclMap(); });
471 
472   if (!DeclMap()->WillParse(exe_ctx, m_materializer_ap.get())) {
473     diagnostic_manager.PutString(
474         eDiagnosticSeverityError,
475         "current process state is unsuitable for expression parsing");
476     return false;
477   }
478 
479   if (m_options.GetExecutionPolicy() == eExecutionPolicyTopLevel) {
480     DeclMap()->SetLookupsEnabled(true);
481   }
482 
483   Process *process = exe_ctx.GetProcessPtr();
484   ExecutionContextScope *exe_scope = process;
485 
486   if (!exe_scope)
487     exe_scope = exe_ctx.GetTargetPtr();
488 
489   // We use a shared pointer here so we can use the original parser - if it
490   // succeeds or the rewrite parser we might make if it fails.  But the
491   // parser_sp will never be empty.
492 
493   ClangExpressionParser parser(exe_scope, *this, generate_debug_info);
494 
495   unsigned num_errors = parser.Parse(diagnostic_manager);
496 
497   // Check here for FixItHints.  If there are any try to apply the fixits and
498   // set the fixed text in m_fixed_text before returning an error.
499   if (num_errors) {
500     if (diagnostic_manager.HasFixIts()) {
501       if (parser.RewriteExpression(diagnostic_manager)) {
502         size_t fixed_start;
503         size_t fixed_end;
504         const std::string &fixed_expression =
505             diagnostic_manager.GetFixedExpression();
506         if (ExpressionSourceCode::GetOriginalBodyBounds(
507                 fixed_expression, lang_type, fixed_start, fixed_end))
508           m_fixed_text =
509               fixed_expression.substr(fixed_start, fixed_end - fixed_start);
510       }
511     }
512     return false;
513   }
514 
515   //////////////////////////////////////////////////////////////////////////////////////////
516   // Prepare the output of the parser for execution, evaluating it statically
517   // if possible
518   //
519 
520   {
521     Status jit_error = parser.PrepareForExecution(
522         m_jit_start_addr, m_jit_end_addr, m_execution_unit_sp, exe_ctx,
523         m_can_interpret, execution_policy);
524 
525     if (!jit_error.Success()) {
526       const char *error_cstr = jit_error.AsCString();
527       if (error_cstr && error_cstr[0])
528         diagnostic_manager.PutString(eDiagnosticSeverityError, error_cstr);
529       else
530         diagnostic_manager.PutString(eDiagnosticSeverityError,
531                                      "expression can't be interpreted or run");
532       return false;
533     }
534   }
535 
536   if (exe_ctx.GetProcessPtr() && execution_policy == eExecutionPolicyTopLevel) {
537     Status static_init_error =
538         parser.RunStaticInitializers(m_execution_unit_sp, exe_ctx);
539 
540     if (!static_init_error.Success()) {
541       const char *error_cstr = static_init_error.AsCString();
542       if (error_cstr && error_cstr[0])
543         diagnostic_manager.Printf(eDiagnosticSeverityError,
544                                   "couldn't run static initializers: %s\n",
545                                   error_cstr);
546       else
547         diagnostic_manager.PutString(eDiagnosticSeverityError,
548                                      "couldn't run static initializers\n");
549       return false;
550     }
551   }
552 
553   if (m_execution_unit_sp) {
554     bool register_execution_unit = false;
555 
556     if (m_options.GetExecutionPolicy() == eExecutionPolicyTopLevel) {
557       register_execution_unit = true;
558     }
559 
560     // If there is more than one external function in the execution unit, it
561     // needs to keep living even if it's not top level, because the result
562     // could refer to that function.
563 
564     if (m_execution_unit_sp->GetJittedFunctions().size() > 1) {
565       register_execution_unit = true;
566     }
567 
568     if (register_execution_unit) {
569       llvm::cast<PersistentExpressionState>(
570           exe_ctx.GetTargetPtr()->GetPersistentExpressionStateForLanguage(
571               m_language))
572           ->RegisterExecutionUnit(m_execution_unit_sp);
573     }
574   }
575 
576   if (generate_debug_info) {
577     lldb::ModuleSP jit_module_sp(m_execution_unit_sp->GetJITModule());
578 
579     if (jit_module_sp) {
580       ConstString const_func_name(FunctionName());
581       FileSpec jit_file;
582       jit_file.GetFilename() = const_func_name;
583       jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
584       m_jit_module_wp = jit_module_sp;
585       target->GetImages().Append(jit_module_sp);
586     }
587   }
588 
589   if (process && m_jit_start_addr != LLDB_INVALID_ADDRESS)
590     m_jit_process_wp = lldb::ProcessWP(process->shared_from_this());
591   return true;
592 }
593 
594 bool ClangUserExpression::AddArguments(ExecutionContext &exe_ctx,
595                                        std::vector<lldb::addr_t> &args,
596                                        lldb::addr_t struct_address,
597                                        DiagnosticManager &diagnostic_manager) {
598   lldb::addr_t object_ptr = LLDB_INVALID_ADDRESS;
599   lldb::addr_t cmd_ptr = LLDB_INVALID_ADDRESS;
600 
601   if (m_needs_object_ptr) {
602     lldb::StackFrameSP frame_sp = exe_ctx.GetFrameSP();
603     if (!frame_sp)
604       return true;
605 
606     ConstString object_name;
607 
608     if (m_in_cplusplus_method) {
609       object_name.SetCString("this");
610     } else if (m_in_objectivec_method) {
611       object_name.SetCString("self");
612     } else {
613       diagnostic_manager.PutString(
614           eDiagnosticSeverityError,
615           "need object pointer but don't know the language");
616       return false;
617     }
618 
619     Status object_ptr_error;
620 
621     object_ptr = GetObjectPointer(frame_sp, object_name, object_ptr_error);
622 
623     if (!object_ptr_error.Success()) {
624       exe_ctx.GetTargetRef().GetDebugger().GetAsyncOutputStream()->Printf(
625           "warning: `%s' is not accessible (substituting 0)\n",
626           object_name.AsCString());
627       object_ptr = 0;
628     }
629 
630     if (m_in_objectivec_method) {
631       ConstString cmd_name("_cmd");
632 
633       cmd_ptr = GetObjectPointer(frame_sp, cmd_name, object_ptr_error);
634 
635       if (!object_ptr_error.Success()) {
636         diagnostic_manager.Printf(
637             eDiagnosticSeverityWarning,
638             "couldn't get cmd pointer (substituting NULL): %s",
639             object_ptr_error.AsCString());
640         cmd_ptr = 0;
641       }
642     }
643 
644     args.push_back(object_ptr);
645 
646     if (m_in_objectivec_method)
647       args.push_back(cmd_ptr);
648 
649     args.push_back(struct_address);
650   } else {
651     args.push_back(struct_address);
652   }
653   return true;
654 }
655 
656 lldb::ExpressionVariableSP ClangUserExpression::GetResultAfterDematerialization(
657     ExecutionContextScope *exe_scope) {
658   return m_result_delegate.GetVariable();
659 }
660 
661 void ClangUserExpression::ClangUserExpressionHelper::ResetDeclMap(
662     ExecutionContext &exe_ctx,
663     Materializer::PersistentVariableDelegate &delegate,
664     bool keep_result_in_memory) {
665   m_expr_decl_map_up.reset(
666       new ClangExpressionDeclMap(keep_result_in_memory, &delegate, exe_ctx));
667 }
668 
669 clang::ASTConsumer *
670 ClangUserExpression::ClangUserExpressionHelper::ASTTransformer(
671     clang::ASTConsumer *passthrough) {
672   m_result_synthesizer_up.reset(
673       new ASTResultSynthesizer(passthrough, m_top_level, m_target));
674 
675   return m_result_synthesizer_up.get();
676 }
677 
678 void ClangUserExpression::ClangUserExpressionHelper::CommitPersistentDecls() {
679   if (m_result_synthesizer_up.get()) {
680     m_result_synthesizer_up->CommitPersistentDecls();
681   }
682 }
683 
684 ConstString ClangUserExpression::ResultDelegate::GetName() {
685   auto prefix = m_persistent_state->GetPersistentVariablePrefix();
686   return m_persistent_state->GetNextPersistentVariableName(*m_target_sp,
687                                                            prefix);
688 }
689 
690 void ClangUserExpression::ResultDelegate::DidDematerialize(
691     lldb::ExpressionVariableSP &variable) {
692   m_variable = variable;
693 }
694 
695 void ClangUserExpression::ResultDelegate::RegisterPersistentState(
696     PersistentExpressionState *persistent_state) {
697   m_persistent_state = persistent_state;
698 }
699 
700 lldb::ExpressionVariableSP &ClangUserExpression::ResultDelegate::GetVariable() {
701   return m_variable;
702 }
703