1 //===-- ClangUserExpression.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/Host/Config.h"
10 
11 #include <stdio.h>
12 #if HAVE_SYS_TYPES_H
13 #include <sys/types.h>
14 #endif
15 
16 #include <cstdlib>
17 #include <map>
18 #include <string>
19 
20 #include "ClangUserExpression.h"
21 
22 #include "ASTResultSynthesizer.h"
23 #include "ClangASTMetadata.h"
24 #include "ClangDiagnostic.h"
25 #include "ClangExpressionDeclMap.h"
26 #include "ClangExpressionParser.h"
27 #include "ClangModulesDeclVendor.h"
28 #include "ClangPersistentVariables.h"
29 #include "CppModuleConfiguration.h"
30 
31 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
32 #include "lldb/Core/Debugger.h"
33 #include "lldb/Core/Module.h"
34 #include "lldb/Core/StreamFile.h"
35 #include "lldb/Core/ValueObjectConstResult.h"
36 #include "lldb/Expression/ExpressionSourceCode.h"
37 #include "lldb/Expression/IRExecutionUnit.h"
38 #include "lldb/Expression/IRInterpreter.h"
39 #include "lldb/Expression/Materializer.h"
40 #include "lldb/Host/HostInfo.h"
41 #include "lldb/Symbol/Block.h"
42 #include "lldb/Symbol/CompileUnit.h"
43 #include "lldb/Symbol/Function.h"
44 #include "lldb/Symbol/ObjectFile.h"
45 #include "lldb/Symbol/SymbolFile.h"
46 #include "lldb/Symbol/SymbolVendor.h"
47 #include "lldb/Symbol/Type.h"
48 #include "lldb/Symbol/VariableList.h"
49 #include "lldb/Target/ExecutionContext.h"
50 #include "lldb/Target/Process.h"
51 #include "lldb/Target/StackFrame.h"
52 #include "lldb/Target/Target.h"
53 #include "lldb/Target/ThreadPlan.h"
54 #include "lldb/Target/ThreadPlanCallUserExpression.h"
55 #include "lldb/Utility/ConstString.h"
56 #include "lldb/Utility/Log.h"
57 #include "lldb/Utility/StreamString.h"
58 
59 #include "clang/AST/DeclCXX.h"
60 #include "clang/AST/DeclObjC.h"
61 
62 #include "llvm/ADT/ScopeExit.h"
63 
64 using namespace lldb_private;
65 
66 char ClangUserExpression::ID;
67 
68 ClangUserExpression::ClangUserExpression(
69     ExecutionContextScope &exe_scope, llvm::StringRef expr,
70     llvm::StringRef prefix, lldb::LanguageType language,
71     ResultType desired_type, const EvaluateExpressionOptions &options,
72     ValueObject *ctx_obj)
73     : LLVMUserExpression(exe_scope, expr, prefix, language, desired_type,
74                          options),
75       m_type_system_helper(*m_target_wp.lock(), options.GetExecutionPolicy() ==
76                                                     eExecutionPolicyTopLevel),
77       m_result_delegate(exe_scope.CalculateTarget()), m_ctx_obj(ctx_obj) {
78   switch (m_language) {
79   case lldb::eLanguageTypeC_plus_plus:
80     m_allow_cxx = true;
81     break;
82   case lldb::eLanguageTypeObjC:
83     m_allow_objc = true;
84     break;
85   case lldb::eLanguageTypeObjC_plus_plus:
86   default:
87     m_allow_cxx = true;
88     m_allow_objc = true;
89     break;
90   }
91 }
92 
93 ClangUserExpression::~ClangUserExpression() {}
94 
95 void ClangUserExpression::ScanContext(ExecutionContext &exe_ctx, Status &err) {
96   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
97 
98   LLDB_LOGF(log, "ClangUserExpression::ScanContext()");
99 
100   m_target = exe_ctx.GetTargetPtr();
101 
102   if (!(m_allow_cxx || m_allow_objc)) {
103     LLDB_LOGF(log, "  [CUE::SC] Settings inhibit C++ and Objective-C");
104     return;
105   }
106 
107   StackFrame *frame = exe_ctx.GetFramePtr();
108   if (frame == nullptr) {
109     LLDB_LOGF(log, "  [CUE::SC] Null stack frame");
110     return;
111   }
112 
113   SymbolContext sym_ctx = frame->GetSymbolContext(lldb::eSymbolContextFunction |
114                                                   lldb::eSymbolContextBlock);
115 
116   if (!sym_ctx.function) {
117     LLDB_LOGF(log, "  [CUE::SC] Null function");
118     return;
119   }
120 
121   // Find the block that defines the function represented by "sym_ctx"
122   Block *function_block = sym_ctx.GetFunctionBlock();
123 
124   if (!function_block) {
125     LLDB_LOGF(log, "  [CUE::SC] Null function block");
126     return;
127   }
128 
129   CompilerDeclContext decl_context = function_block->GetDeclContext();
130 
131   if (!decl_context) {
132     LLDB_LOGF(log, "  [CUE::SC] Null decl context");
133     return;
134   }
135 
136   if (m_ctx_obj) {
137     switch (m_ctx_obj->GetObjectRuntimeLanguage()) {
138     case lldb::eLanguageTypeC:
139     case lldb::eLanguageTypeC89:
140     case lldb::eLanguageTypeC99:
141     case lldb::eLanguageTypeC11:
142     case lldb::eLanguageTypeC_plus_plus:
143     case lldb::eLanguageTypeC_plus_plus_03:
144     case lldb::eLanguageTypeC_plus_plus_11:
145     case lldb::eLanguageTypeC_plus_plus_14:
146       m_in_cplusplus_method = true;
147       break;
148     case lldb::eLanguageTypeObjC:
149     case lldb::eLanguageTypeObjC_plus_plus:
150       m_in_objectivec_method = true;
151       break;
152     default:
153       break;
154     }
155     m_needs_object_ptr = true;
156   } else if (clang::CXXMethodDecl *method_decl =
157           TypeSystemClang::DeclContextGetAsCXXMethodDecl(decl_context)) {
158     if (m_allow_cxx && method_decl->isInstance()) {
159       if (m_enforce_valid_object) {
160         lldb::VariableListSP variable_list_sp(
161             function_block->GetBlockVariableList(true));
162 
163         const char *thisErrorString = "Stopped in a C++ method, but 'this' "
164                                       "isn't available; pretending we are in a "
165                                       "generic context";
166 
167         if (!variable_list_sp) {
168           err.SetErrorString(thisErrorString);
169           return;
170         }
171 
172         lldb::VariableSP this_var_sp(
173             variable_list_sp->FindVariable(ConstString("this")));
174 
175         if (!this_var_sp || !this_var_sp->IsInScope(frame) ||
176             !this_var_sp->LocationIsValidForFrame(frame)) {
177           err.SetErrorString(thisErrorString);
178           return;
179         }
180       }
181 
182       m_in_cplusplus_method = true;
183       m_needs_object_ptr = true;
184     }
185   } else if (clang::ObjCMethodDecl *method_decl =
186                  TypeSystemClang::DeclContextGetAsObjCMethodDecl(
187                      decl_context)) {
188     if (m_allow_objc) {
189       if (m_enforce_valid_object) {
190         lldb::VariableListSP variable_list_sp(
191             function_block->GetBlockVariableList(true));
192 
193         const char *selfErrorString = "Stopped in an Objective-C method, but "
194                                       "'self' isn't available; pretending we "
195                                       "are in a generic context";
196 
197         if (!variable_list_sp) {
198           err.SetErrorString(selfErrorString);
199           return;
200         }
201 
202         lldb::VariableSP self_variable_sp =
203             variable_list_sp->FindVariable(ConstString("self"));
204 
205         if (!self_variable_sp || !self_variable_sp->IsInScope(frame) ||
206             !self_variable_sp->LocationIsValidForFrame(frame)) {
207           err.SetErrorString(selfErrorString);
208           return;
209         }
210       }
211 
212       m_in_objectivec_method = true;
213       m_needs_object_ptr = true;
214 
215       if (!method_decl->isInstanceMethod())
216         m_in_static_method = true;
217     }
218   } else if (clang::FunctionDecl *function_decl =
219                  TypeSystemClang::DeclContextGetAsFunctionDecl(decl_context)) {
220     // We might also have a function that said in the debug information that it
221     // captured an object pointer.  The best way to deal with getting to the
222     // ivars at present is by pretending that this is a method of a class in
223     // whatever runtime the debug info says the object pointer belongs to.  Do
224     // that here.
225 
226     ClangASTMetadata *metadata =
227         TypeSystemClang::DeclContextGetMetaData(decl_context, function_decl);
228     if (metadata && metadata->HasObjectPtr()) {
229       lldb::LanguageType language = metadata->GetObjectPtrLanguage();
230       if (language == lldb::eLanguageTypeC_plus_plus) {
231         if (m_enforce_valid_object) {
232           lldb::VariableListSP variable_list_sp(
233               function_block->GetBlockVariableList(true));
234 
235           const char *thisErrorString = "Stopped in a context claiming to "
236                                         "capture a C++ object pointer, but "
237                                         "'this' isn't available; pretending we "
238                                         "are in a generic context";
239 
240           if (!variable_list_sp) {
241             err.SetErrorString(thisErrorString);
242             return;
243           }
244 
245           lldb::VariableSP this_var_sp(
246               variable_list_sp->FindVariable(ConstString("this")));
247 
248           if (!this_var_sp || !this_var_sp->IsInScope(frame) ||
249               !this_var_sp->LocationIsValidForFrame(frame)) {
250             err.SetErrorString(thisErrorString);
251             return;
252           }
253         }
254 
255         m_in_cplusplus_method = true;
256         m_needs_object_ptr = true;
257       } else if (language == lldb::eLanguageTypeObjC) {
258         if (m_enforce_valid_object) {
259           lldb::VariableListSP variable_list_sp(
260               function_block->GetBlockVariableList(true));
261 
262           const char *selfErrorString =
263               "Stopped in a context claiming to capture an Objective-C object "
264               "pointer, but 'self' isn't available; pretending we are in a "
265               "generic context";
266 
267           if (!variable_list_sp) {
268             err.SetErrorString(selfErrorString);
269             return;
270           }
271 
272           lldb::VariableSP self_variable_sp =
273               variable_list_sp->FindVariable(ConstString("self"));
274 
275           if (!self_variable_sp || !self_variable_sp->IsInScope(frame) ||
276               !self_variable_sp->LocationIsValidForFrame(frame)) {
277             err.SetErrorString(selfErrorString);
278             return;
279           }
280 
281           Type *self_type = self_variable_sp->GetType();
282 
283           if (!self_type) {
284             err.SetErrorString(selfErrorString);
285             return;
286           }
287 
288           CompilerType self_clang_type = self_type->GetForwardCompilerType();
289 
290           if (!self_clang_type) {
291             err.SetErrorString(selfErrorString);
292             return;
293           }
294 
295           if (TypeSystemClang::IsObjCClassType(self_clang_type)) {
296             return;
297           } else if (TypeSystemClang::IsObjCObjectPointerType(
298                          self_clang_type)) {
299             m_in_objectivec_method = true;
300             m_needs_object_ptr = true;
301           } else {
302             err.SetErrorString(selfErrorString);
303             return;
304           }
305         } else {
306           m_in_objectivec_method = true;
307           m_needs_object_ptr = true;
308         }
309       }
310     }
311   }
312 }
313 
314 // This is a really nasty hack, meant to fix Objective-C expressions of the
315 // form (int)[myArray count].  Right now, because the type information for
316 // count is not available, [myArray count] returns id, which can't be directly
317 // cast to int without causing a clang error.
318 static void ApplyObjcCastHack(std::string &expr) {
319   const std::string from = "(int)[";
320   const std::string to = "(int)(long long)[";
321 
322   size_t offset;
323 
324   while ((offset = expr.find(from)) != expr.npos)
325     expr.replace(offset, from.size(), to);
326 }
327 
328 bool ClangUserExpression::SetupPersistentState(DiagnosticManager &diagnostic_manager,
329                                  ExecutionContext &exe_ctx) {
330   if (Target *target = exe_ctx.GetTargetPtr()) {
331     if (PersistentExpressionState *persistent_state =
332             target->GetPersistentExpressionStateForLanguage(
333                 lldb::eLanguageTypeC)) {
334       m_clang_state = llvm::cast<ClangPersistentVariables>(persistent_state);
335       m_result_delegate.RegisterPersistentState(persistent_state);
336     } else {
337       diagnostic_manager.PutString(
338           eDiagnosticSeverityError,
339           "couldn't start parsing (no persistent data)");
340       return false;
341     }
342   } else {
343     diagnostic_manager.PutString(eDiagnosticSeverityError,
344                                  "error: couldn't start parsing (no target)");
345     return false;
346   }
347   return true;
348 }
349 
350 static void SetupDeclVendor(ExecutionContext &exe_ctx, Target *target,
351                             DiagnosticManager &diagnostic_manager) {
352   ClangModulesDeclVendor *decl_vendor = target->GetClangModulesDeclVendor();
353   if (!decl_vendor)
354     return;
355 
356   if (!target->GetEnableAutoImportClangModules())
357     return;
358 
359   auto *persistent_state = llvm::cast<ClangPersistentVariables>(
360       target->GetPersistentExpressionStateForLanguage(lldb::eLanguageTypeC));
361   if (!persistent_state)
362     return;
363 
364   StackFrame *frame = exe_ctx.GetFramePtr();
365   if (!frame)
366     return;
367 
368   Block *block = frame->GetFrameBlock();
369   if (!block)
370     return;
371   SymbolContext sc;
372 
373   block->CalculateSymbolContext(&sc);
374 
375   if (!sc.comp_unit)
376     return;
377   StreamString error_stream;
378 
379   ClangModulesDeclVendor::ModuleVector modules_for_macros =
380       persistent_state->GetHandLoadedClangModules();
381   if (decl_vendor->AddModulesForCompileUnit(*sc.comp_unit, modules_for_macros,
382                                             error_stream))
383     return;
384 
385   // Failed to load some modules, so emit the error stream as a diagnostic.
386   if (!error_stream.Empty()) {
387     // The error stream already contains several Clang diagnostics that might
388     // be either errors or warnings, so just print them all as one remark
389     // diagnostic to prevent that the message starts with "error: error:".
390     diagnostic_manager.PutString(eDiagnosticSeverityRemark,
391                                  error_stream.GetString());
392     return;
393   }
394 
395   diagnostic_manager.PutString(eDiagnosticSeverityError,
396                                "Unknown error while loading modules needed for "
397                                "current compilation unit.");
398 }
399 
400 ClangExpressionSourceCode::WrapKind ClangUserExpression::GetWrapKind() const {
401   assert(m_options.GetExecutionPolicy() != eExecutionPolicyTopLevel &&
402          "Top level expressions aren't wrapped.");
403   using Kind = ClangExpressionSourceCode::WrapKind;
404   if (m_in_cplusplus_method)
405     return Kind::CppMemberFunction;
406   else if (m_in_objectivec_method) {
407     if (m_in_static_method)
408       return Kind::ObjCStaticMethod;
409     return Kind::ObjCInstanceMethod;
410   }
411   // Not in any kind of 'special' function, so just wrap it in a normal C
412   // function.
413   return Kind::Function;
414 }
415 
416 void ClangUserExpression::CreateSourceCode(
417     DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx,
418     std::vector<std::string> modules_to_import, bool for_completion) {
419 
420   std::string prefix = m_expr_prefix;
421 
422   if (m_options.GetExecutionPolicy() == eExecutionPolicyTopLevel) {
423     m_transformed_text = m_expr_text;
424   } else {
425     m_source_code.reset(ClangExpressionSourceCode::CreateWrapped(
426         m_filename, prefix, m_expr_text, GetWrapKind()));
427 
428     if (!m_source_code->GetText(m_transformed_text, exe_ctx, !m_ctx_obj,
429                                 for_completion, modules_to_import)) {
430       diagnostic_manager.PutString(eDiagnosticSeverityError,
431                                    "couldn't construct expression body");
432       return;
433     }
434 
435     // Find and store the start position of the original code inside the
436     // transformed code. We need this later for the code completion.
437     std::size_t original_start;
438     std::size_t original_end;
439     bool found_bounds = m_source_code->GetOriginalBodyBounds(
440         m_transformed_text, original_start, original_end);
441     if (found_bounds)
442       m_user_expression_start_pos = original_start;
443   }
444 }
445 
446 static bool SupportsCxxModuleImport(lldb::LanguageType language) {
447   switch (language) {
448   case lldb::eLanguageTypeC_plus_plus:
449   case lldb::eLanguageTypeC_plus_plus_03:
450   case lldb::eLanguageTypeC_plus_plus_11:
451   case lldb::eLanguageTypeC_plus_plus_14:
452   case lldb::eLanguageTypeObjC_plus_plus:
453     return true;
454   default:
455     return false;
456   }
457 }
458 
459 /// Utility method that puts a message into the expression log and
460 /// returns an invalid module configuration.
461 static CppModuleConfiguration LogConfigError(const std::string &msg) {
462   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
463   LLDB_LOG(log, "[C++ module config] {0}", msg);
464   return CppModuleConfiguration();
465 }
466 
467 CppModuleConfiguration GetModuleConfig(lldb::LanguageType language,
468                                        ExecutionContext &exe_ctx) {
469   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
470 
471   // Don't do anything if this is not a C++ module configuration.
472   if (!SupportsCxxModuleImport(language))
473     return LogConfigError("Language doesn't support C++ modules");
474 
475   Target *target = exe_ctx.GetTargetPtr();
476   if (!target)
477     return LogConfigError("No target");
478 
479   StackFrame *frame = exe_ctx.GetFramePtr();
480   if (!frame)
481     return LogConfigError("No frame");
482 
483   Block *block = frame->GetFrameBlock();
484   if (!block)
485     return LogConfigError("No block");
486 
487   SymbolContext sc;
488   block->CalculateSymbolContext(&sc);
489   if (!sc.comp_unit)
490     return LogConfigError("Couldn't calculate symbol context");
491 
492   // Build a list of files we need to analyze to build the configuration.
493   FileSpecList files;
494   for (const FileSpec &f : sc.comp_unit->GetSupportFiles())
495     files.AppendIfUnique(f);
496   // We also need to look at external modules in the case of -gmodules as they
497   // contain the support files for libc++ and the C library.
498   llvm::DenseSet<SymbolFile *> visited_symbol_files;
499   sc.comp_unit->ForEachExternalModule(
500       visited_symbol_files, [&files](Module &module) {
501         for (std::size_t i = 0; i < module.GetNumCompileUnits(); ++i) {
502           const FileSpecList &support_files =
503               module.GetCompileUnitAtIndex(i)->GetSupportFiles();
504           for (const FileSpec &f : support_files) {
505             files.AppendIfUnique(f);
506           }
507         }
508         return false;
509       });
510 
511   LLDB_LOG(log, "[C++ module config] Found {0} support files to analyze",
512            files.GetSize());
513   if (log && log->GetVerbose()) {
514     for (const FileSpec &f : files)
515       LLDB_LOGV(log, "[C++ module config] Analyzing support file: {0}",
516                 f.GetPath());
517   }
518 
519   // Try to create a configuration from the files. If there is no valid
520   // configuration possible with the files, this just returns an invalid
521   // configuration.
522   return CppModuleConfiguration(files);
523 }
524 
525 bool ClangUserExpression::PrepareForParsing(
526     DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx,
527     bool for_completion) {
528   InstallContext(exe_ctx);
529 
530   if (!SetupPersistentState(diagnostic_manager, exe_ctx))
531     return false;
532 
533   Status err;
534   ScanContext(exe_ctx, err);
535 
536   if (!err.Success()) {
537     diagnostic_manager.PutString(eDiagnosticSeverityWarning, err.AsCString());
538   }
539 
540   ////////////////////////////////////
541   // Generate the expression
542   //
543 
544   ApplyObjcCastHack(m_expr_text);
545 
546   SetupDeclVendor(exe_ctx, m_target, diagnostic_manager);
547 
548   m_filename = m_clang_state->GetNextExprFileName();
549 
550   if (m_target->GetImportStdModule() == eImportStdModuleTrue)
551     SetupCppModuleImports(exe_ctx);
552 
553   CreateSourceCode(diagnostic_manager, exe_ctx, m_imported_cpp_modules,
554                    for_completion);
555   return true;
556 }
557 
558 bool ClangUserExpression::TryParse(
559     DiagnosticManager &diagnostic_manager, ExecutionContextScope *exe_scope,
560     ExecutionContext &exe_ctx, lldb_private::ExecutionPolicy execution_policy,
561     bool keep_result_in_memory, bool generate_debug_info) {
562   m_materializer_up = std::make_unique<Materializer>();
563 
564   ResetDeclMap(exe_ctx, m_result_delegate, keep_result_in_memory);
565 
566   auto on_exit = llvm::make_scope_exit([this]() { ResetDeclMap(); });
567 
568   if (!DeclMap()->WillParse(exe_ctx, GetMaterializer())) {
569     diagnostic_manager.PutString(
570         eDiagnosticSeverityError,
571         "current process state is unsuitable for expression parsing");
572     return false;
573   }
574 
575   if (m_options.GetExecutionPolicy() == eExecutionPolicyTopLevel) {
576     DeclMap()->SetLookupsEnabled(true);
577   }
578 
579   m_parser = std::make_unique<ClangExpressionParser>(
580       exe_scope, *this, generate_debug_info, m_include_directories, m_filename);
581 
582   unsigned num_errors = m_parser->Parse(diagnostic_manager);
583 
584   // Check here for FixItHints.  If there are any try to apply the fixits and
585   // set the fixed text in m_fixed_text before returning an error.
586   if (num_errors) {
587     if (diagnostic_manager.HasFixIts()) {
588       if (m_parser->RewriteExpression(diagnostic_manager)) {
589         size_t fixed_start;
590         size_t fixed_end;
591         m_fixed_text = diagnostic_manager.GetFixedExpression();
592         // Retrieve the original expression in case we don't have a top level
593         // expression (which has no surrounding source code).
594         if (m_source_code && m_source_code->GetOriginalBodyBounds(
595                                  m_fixed_text, fixed_start, fixed_end))
596           m_fixed_text =
597               m_fixed_text.substr(fixed_start, fixed_end - fixed_start);
598       }
599     }
600     return false;
601   }
602 
603   //////////////////////////////////////////////////////////////////////////////
604   // Prepare the output of the parser for execution, evaluating it statically
605   // if possible
606   //
607 
608   {
609     Status jit_error = m_parser->PrepareForExecution(
610         m_jit_start_addr, m_jit_end_addr, m_execution_unit_sp, exe_ctx,
611         m_can_interpret, execution_policy);
612 
613     if (!jit_error.Success()) {
614       const char *error_cstr = jit_error.AsCString();
615       if (error_cstr && error_cstr[0])
616         diagnostic_manager.PutString(eDiagnosticSeverityError, error_cstr);
617       else
618         diagnostic_manager.PutString(eDiagnosticSeverityError,
619                                      "expression can't be interpreted or run");
620       return false;
621     }
622   }
623   return true;
624 }
625 
626 void ClangUserExpression::SetupCppModuleImports(ExecutionContext &exe_ctx) {
627   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
628 
629   CppModuleConfiguration module_config = GetModuleConfig(m_language, exe_ctx);
630   m_imported_cpp_modules = module_config.GetImportedModules();
631   m_include_directories = module_config.GetIncludeDirs();
632 
633   LLDB_LOG(log, "List of imported modules in expression: {0}",
634            llvm::make_range(m_imported_cpp_modules.begin(),
635                             m_imported_cpp_modules.end()));
636   LLDB_LOG(log, "List of include directories gathered for modules: {0}",
637            llvm::make_range(m_include_directories.begin(),
638                             m_include_directories.end()));
639 }
640 
641 static bool shouldRetryWithCppModule(Target &target, ExecutionPolicy exe_policy) {
642   // Top-level expression don't yet support importing C++ modules.
643   if (exe_policy == ExecutionPolicy::eExecutionPolicyTopLevel)
644     return false;
645   return target.GetImportStdModule() == eImportStdModuleFallback;
646 }
647 
648 bool ClangUserExpression::Parse(DiagnosticManager &diagnostic_manager,
649                                 ExecutionContext &exe_ctx,
650                                 lldb_private::ExecutionPolicy execution_policy,
651                                 bool keep_result_in_memory,
652                                 bool generate_debug_info) {
653   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
654 
655   if (!PrepareForParsing(diagnostic_manager, exe_ctx, /*for_completion*/ false))
656     return false;
657 
658   LLDB_LOGF(log, "Parsing the following code:\n%s", m_transformed_text.c_str());
659 
660   ////////////////////////////////////
661   // Set up the target and compiler
662   //
663 
664   Target *target = exe_ctx.GetTargetPtr();
665 
666   if (!target) {
667     diagnostic_manager.PutString(eDiagnosticSeverityError, "invalid target");
668     return false;
669   }
670 
671   //////////////////////////
672   // Parse the expression
673   //
674 
675   Process *process = exe_ctx.GetProcessPtr();
676   ExecutionContextScope *exe_scope = process;
677 
678   if (!exe_scope)
679     exe_scope = exe_ctx.GetTargetPtr();
680 
681   bool parse_success = TryParse(diagnostic_manager, exe_scope, exe_ctx,
682                                 execution_policy, keep_result_in_memory,
683                                 generate_debug_info);
684   // If the expression failed to parse, check if retrying parsing with a loaded
685   // C++ module is possible.
686   if (!parse_success && shouldRetryWithCppModule(*target, execution_policy)) {
687     // Load the loaded C++ modules.
688     SetupCppModuleImports(exe_ctx);
689     // If we did load any modules, then retry parsing.
690     if (!m_imported_cpp_modules.empty()) {
691       // The module imports are injected into the source code wrapper,
692       // so recreate those.
693       CreateSourceCode(diagnostic_manager, exe_ctx, m_imported_cpp_modules,
694                        /*for_completion*/ false);
695       // Clear the error diagnostics from the previous parse attempt.
696       diagnostic_manager.Clear();
697       parse_success = TryParse(diagnostic_manager, exe_scope, exe_ctx,
698                                execution_policy, keep_result_in_memory,
699                                generate_debug_info);
700     }
701   }
702   if (!parse_success)
703     return false;
704 
705   if (exe_ctx.GetProcessPtr() && execution_policy == eExecutionPolicyTopLevel) {
706     Status static_init_error =
707         m_parser->RunStaticInitializers(m_execution_unit_sp, exe_ctx);
708 
709     if (!static_init_error.Success()) {
710       const char *error_cstr = static_init_error.AsCString();
711       if (error_cstr && error_cstr[0])
712         diagnostic_manager.Printf(eDiagnosticSeverityError,
713                                   "%s\n",
714                                   error_cstr);
715       else
716         diagnostic_manager.PutString(eDiagnosticSeverityError,
717                                      "couldn't run static initializers\n");
718       return false;
719     }
720   }
721 
722   if (m_execution_unit_sp) {
723     bool register_execution_unit = false;
724 
725     if (m_options.GetExecutionPolicy() == eExecutionPolicyTopLevel) {
726       register_execution_unit = true;
727     }
728 
729     // If there is more than one external function in the execution unit, it
730     // needs to keep living even if it's not top level, because the result
731     // could refer to that function.
732 
733     if (m_execution_unit_sp->GetJittedFunctions().size() > 1) {
734       register_execution_unit = true;
735     }
736 
737     if (register_execution_unit) {
738       if (auto *persistent_state =
739               exe_ctx.GetTargetPtr()->GetPersistentExpressionStateForLanguage(
740                   m_language))
741         persistent_state->RegisterExecutionUnit(m_execution_unit_sp);
742     }
743   }
744 
745   if (generate_debug_info) {
746     lldb::ModuleSP jit_module_sp(m_execution_unit_sp->GetJITModule());
747 
748     if (jit_module_sp) {
749       ConstString const_func_name(FunctionName());
750       FileSpec jit_file;
751       jit_file.GetFilename() = const_func_name;
752       jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
753       m_jit_module_wp = jit_module_sp;
754       target->GetImages().Append(jit_module_sp);
755     }
756   }
757 
758   if (process && m_jit_start_addr != LLDB_INVALID_ADDRESS)
759     m_jit_process_wp = lldb::ProcessWP(process->shared_from_this());
760   return true;
761 }
762 
763 /// Converts an absolute position inside a given code string into
764 /// a column/line pair.
765 ///
766 /// \param[in] abs_pos
767 ///     A absolute position in the code string that we want to convert
768 ///     to a column/line pair.
769 ///
770 /// \param[in] code
771 ///     A multi-line string usually representing source code.
772 ///
773 /// \param[out] line
774 ///     The line in the code that contains the given absolute position.
775 ///     The first line in the string is indexed as 1.
776 ///
777 /// \param[out] column
778 ///     The column in the line that contains the absolute position.
779 ///     The first character in a line is indexed as 0.
780 static void AbsPosToLineColumnPos(size_t abs_pos, llvm::StringRef code,
781                                   unsigned &line, unsigned &column) {
782   // Reset to code position to beginning of the file.
783   line = 0;
784   column = 0;
785 
786   assert(abs_pos <= code.size() && "Absolute position outside code string?");
787 
788   // We have to walk up to the position and count lines/columns.
789   for (std::size_t i = 0; i < abs_pos; ++i) {
790     // If we hit a line break, we go back to column 0 and enter a new line.
791     // We only handle \n because that's what we internally use to make new
792     // lines for our temporary code strings.
793     if (code[i] == '\n') {
794       ++line;
795       column = 0;
796       continue;
797     }
798     ++column;
799   }
800 }
801 
802 bool ClangUserExpression::Complete(ExecutionContext &exe_ctx,
803                                    CompletionRequest &request,
804                                    unsigned complete_pos) {
805   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
806 
807   // We don't want any visible feedback when completing an expression. Mostly
808   // because the results we get from an incomplete invocation are probably not
809   // correct.
810   DiagnosticManager diagnostic_manager;
811 
812   if (!PrepareForParsing(diagnostic_manager, exe_ctx, /*for_completion*/ true))
813     return false;
814 
815   LLDB_LOGF(log, "Parsing the following code:\n%s", m_transformed_text.c_str());
816 
817   //////////////////////////
818   // Parse the expression
819   //
820 
821   m_materializer_up = std::make_unique<Materializer>();
822 
823   ResetDeclMap(exe_ctx, m_result_delegate, /*keep result in memory*/ true);
824 
825   auto on_exit = llvm::make_scope_exit([this]() { ResetDeclMap(); });
826 
827   if (!DeclMap()->WillParse(exe_ctx, GetMaterializer())) {
828     diagnostic_manager.PutString(
829         eDiagnosticSeverityError,
830         "current process state is unsuitable for expression parsing");
831 
832     return false;
833   }
834 
835   if (m_options.GetExecutionPolicy() == eExecutionPolicyTopLevel) {
836     DeclMap()->SetLookupsEnabled(true);
837   }
838 
839   Process *process = exe_ctx.GetProcessPtr();
840   ExecutionContextScope *exe_scope = process;
841 
842   if (!exe_scope)
843     exe_scope = exe_ctx.GetTargetPtr();
844 
845   ClangExpressionParser parser(exe_scope, *this, false);
846 
847   // We have to find the source code location where the user text is inside
848   // the transformed expression code. When creating the transformed text, we
849   // already stored the absolute position in the m_transformed_text string. The
850   // only thing left to do is to transform it into the line:column format that
851   // Clang expects.
852 
853   // The line and column of the user expression inside the transformed source
854   // code.
855   unsigned user_expr_line, user_expr_column;
856   if (m_user_expression_start_pos.hasValue())
857     AbsPosToLineColumnPos(*m_user_expression_start_pos, m_transformed_text,
858                           user_expr_line, user_expr_column);
859   else
860     return false;
861 
862   // The actual column where we have to complete is the start column of the
863   // user expression + the offset inside the user code that we were given.
864   const unsigned completion_column = user_expr_column + complete_pos;
865   parser.Complete(request, user_expr_line, completion_column, complete_pos);
866 
867   return true;
868 }
869 
870 bool ClangUserExpression::AddArguments(ExecutionContext &exe_ctx,
871                                        std::vector<lldb::addr_t> &args,
872                                        lldb::addr_t struct_address,
873                                        DiagnosticManager &diagnostic_manager) {
874   lldb::addr_t object_ptr = LLDB_INVALID_ADDRESS;
875   lldb::addr_t cmd_ptr = LLDB_INVALID_ADDRESS;
876 
877   if (m_needs_object_ptr) {
878     lldb::StackFrameSP frame_sp = exe_ctx.GetFrameSP();
879     if (!frame_sp)
880       return true;
881 
882     ConstString object_name;
883 
884     if (m_in_cplusplus_method) {
885       object_name.SetCString("this");
886     } else if (m_in_objectivec_method) {
887       object_name.SetCString("self");
888     } else {
889       diagnostic_manager.PutString(
890           eDiagnosticSeverityError,
891           "need object pointer but don't know the language");
892       return false;
893     }
894 
895     Status object_ptr_error;
896 
897     if (m_ctx_obj) {
898       AddressType address_type;
899       object_ptr = m_ctx_obj->GetAddressOf(false, &address_type);
900       if (object_ptr == LLDB_INVALID_ADDRESS ||
901           address_type != eAddressTypeLoad)
902         object_ptr_error.SetErrorString("Can't get context object's "
903                                         "debuggee address");
904     } else
905       object_ptr = GetObjectPointer(frame_sp, object_name, object_ptr_error);
906 
907     if (!object_ptr_error.Success()) {
908       exe_ctx.GetTargetRef().GetDebugger().GetAsyncOutputStream()->Printf(
909           "warning: `%s' is not accessible (substituting 0)\n",
910           object_name.AsCString());
911       object_ptr = 0;
912     }
913 
914     if (m_in_objectivec_method) {
915       ConstString cmd_name("_cmd");
916 
917       cmd_ptr = GetObjectPointer(frame_sp, cmd_name, object_ptr_error);
918 
919       if (!object_ptr_error.Success()) {
920         diagnostic_manager.Printf(
921             eDiagnosticSeverityWarning,
922             "couldn't get cmd pointer (substituting NULL): %s",
923             object_ptr_error.AsCString());
924         cmd_ptr = 0;
925       }
926     }
927 
928     args.push_back(object_ptr);
929 
930     if (m_in_objectivec_method)
931       args.push_back(cmd_ptr);
932 
933     args.push_back(struct_address);
934   } else {
935     args.push_back(struct_address);
936   }
937   return true;
938 }
939 
940 lldb::ExpressionVariableSP ClangUserExpression::GetResultAfterDematerialization(
941     ExecutionContextScope *exe_scope) {
942   return m_result_delegate.GetVariable();
943 }
944 
945 void ClangUserExpression::ClangUserExpressionHelper::ResetDeclMap(
946     ExecutionContext &exe_ctx,
947     Materializer::PersistentVariableDelegate &delegate,
948     bool keep_result_in_memory,
949     ValueObject *ctx_obj) {
950   std::shared_ptr<ClangASTImporter> ast_importer;
951   auto *state = exe_ctx.GetTargetSP()->GetPersistentExpressionStateForLanguage(
952       lldb::eLanguageTypeC);
953   if (state) {
954     auto *persistent_vars = llvm::cast<ClangPersistentVariables>(state);
955     ast_importer = persistent_vars->GetClangASTImporter();
956   }
957   m_expr_decl_map_up = std::make_unique<ClangExpressionDeclMap>(
958       keep_result_in_memory, &delegate, exe_ctx.GetTargetSP(), ast_importer,
959       ctx_obj);
960 }
961 
962 clang::ASTConsumer *
963 ClangUserExpression::ClangUserExpressionHelper::ASTTransformer(
964     clang::ASTConsumer *passthrough) {
965   m_result_synthesizer_up = std::make_unique<ASTResultSynthesizer>(
966       passthrough, m_top_level, m_target);
967 
968   return m_result_synthesizer_up.get();
969 }
970 
971 void ClangUserExpression::ClangUserExpressionHelper::CommitPersistentDecls() {
972   if (m_result_synthesizer_up) {
973     m_result_synthesizer_up->CommitPersistentDecls();
974   }
975 }
976 
977 ConstString ClangUserExpression::ResultDelegate::GetName() {
978   return m_persistent_state->GetNextPersistentVariableName(false);
979 }
980 
981 void ClangUserExpression::ResultDelegate::DidDematerialize(
982     lldb::ExpressionVariableSP &variable) {
983   m_variable = variable;
984 }
985 
986 void ClangUserExpression::ResultDelegate::RegisterPersistentState(
987     PersistentExpressionState *persistent_state) {
988   m_persistent_state = persistent_state;
989 }
990 
991 lldb::ExpressionVariableSP &ClangUserExpression::ResultDelegate::GetVariable() {
992   return m_variable;
993 }
994