1 //===-- ClangExpressionParser.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 "ClangExpressionParser.h"
11 
12 #include "ClangASTSource.h"
13 #include "ClangExpressionHelper.h"
14 #include "ClangExpressionDeclMap.h"
15 #include "ClangModulesDeclVendor.h"
16 #include "ClangPersistentVariables.h"
17 #include "IRForTarget.h"
18 
19 #include "lldb/Core/ArchSpec.h"
20 #include "lldb/Core/DataBufferHeap.h"
21 #include "lldb/Core/Debugger.h"
22 #include "lldb/Core/Disassembler.h"
23 #include "lldb/Core/Log.h"
24 #include "lldb/Core/Module.h"
25 #include "lldb/Core/Stream.h"
26 #include "lldb/Core/StreamFile.h"
27 #include "lldb/Core/StreamString.h"
28 #include "lldb/Expression/IRExecutionUnit.h"
29 #include "lldb/Expression/IRDynamicChecks.h"
30 #include "lldb/Expression/IRInterpreter.h"
31 #include "lldb/Host/File.h"
32 #include "lldb/Host/HostInfo.h"
33 #include "lldb/Symbol/ClangASTContext.h"
34 #include "lldb/Symbol/SymbolVendor.h"
35 #include "lldb/Target/ExecutionContext.h"
36 #include "lldb/Target/ObjCLanguageRuntime.h"
37 #include "lldb/Target/Process.h"
38 #include "lldb/Target/Target.h"
39 
40 #include "clang/AST/ASTContext.h"
41 #include "clang/AST/ExternalASTSource.h"
42 #include "clang/Basic/FileManager.h"
43 #include "clang/Basic/SourceLocation.h"
44 #include "clang/Basic/TargetInfo.h"
45 #include "clang/Basic/Version.h"
46 #include "clang/CodeGen/CodeGenAction.h"
47 #include "clang/CodeGen/ModuleBuilder.h"
48 #include "clang/Frontend/CompilerInstance.h"
49 #include "clang/Frontend/CompilerInvocation.h"
50 #include "clang/Frontend/FrontendActions.h"
51 #include "clang/Frontend/FrontendDiagnostic.h"
52 #include "clang/Frontend/FrontendPluginRegistry.h"
53 #include "clang/Frontend/TextDiagnosticBuffer.h"
54 #include "clang/Frontend/TextDiagnosticPrinter.h"
55 #include "clang/Lex/Preprocessor.h"
56 #include "clang/Parse/ParseAST.h"
57 #include "clang/Rewrite/Frontend/FrontendActions.h"
58 #include "clang/Sema/SemaConsumer.h"
59 #include "clang/StaticAnalyzer/Frontend/FrontendActions.h"
60 
61 #include "llvm/ADT/StringRef.h"
62 #include "llvm/ExecutionEngine/ExecutionEngine.h"
63 #include "llvm/Support/Debug.h"
64 #include "llvm/Support/FileSystem.h"
65 #include "llvm/Support/TargetSelect.h"
66 
67 #include "llvm/ExecutionEngine/MCJIT.h"
68 #include "llvm/IR/LLVMContext.h"
69 #include "llvm/IR/Module.h"
70 #include "llvm/Support/ErrorHandling.h"
71 #include "llvm/Support/MemoryBuffer.h"
72 #include "llvm/Support/DynamicLibrary.h"
73 #include "llvm/Support/Host.h"
74 #include "llvm/Support/Signals.h"
75 
76 using namespace clang;
77 using namespace llvm;
78 using namespace lldb_private;
79 
80 //===----------------------------------------------------------------------===//
81 // Utility Methods for Clang
82 //===----------------------------------------------------------------------===//
83 
84 std::string GetBuiltinIncludePath(const char *Argv0) {
85     SmallString<128> P(llvm::sys::fs::getMainExecutable(
86         Argv0, (void *)(intptr_t) GetBuiltinIncludePath));
87 
88     if (!P.empty()) {
89         llvm::sys::path::remove_filename(P); // Remove /clang from foo/bin/clang
90         llvm::sys::path::remove_filename(P); // Remove /bin   from foo/bin
91 
92         // Get foo/lib/clang/<version>/include
93         llvm::sys::path::append(P, "lib", "clang", CLANG_VERSION_STRING,
94                                 "include");
95     }
96 
97     return P.str();
98 }
99 
100 class ClangExpressionParser::LLDBPreprocessorCallbacks : public PPCallbacks
101 {
102     ClangModulesDeclVendor     &m_decl_vendor;
103     ClangPersistentVariables   &m_persistent_vars;
104     StreamString                m_error_stream;
105     bool                        m_has_errors = false;
106 public:
107     LLDBPreprocessorCallbacks(ClangModulesDeclVendor &decl_vendor,
108                               ClangPersistentVariables &persistent_vars) :
109         m_decl_vendor(decl_vendor),
110         m_persistent_vars(persistent_vars)
111     {
112     }
113 
114     virtual void moduleImport(SourceLocation import_location,
115                               clang::ModuleIdPath path,
116                               const clang::Module * /*null*/)
117     {
118         std::vector<ConstString> string_path;
119 
120         for (const std::pair<IdentifierInfo *, SourceLocation> &component : path)
121         {
122             string_path.push_back(ConstString(component.first->getName()));
123         }
124 
125         StreamString error_stream;
126 
127         ClangModulesDeclVendor::ModuleVector exported_modules;
128 
129         if (!m_decl_vendor.AddModule(string_path, &exported_modules, m_error_stream))
130         {
131             m_has_errors = true;
132         }
133 
134         for (ClangModulesDeclVendor::ModuleID module : exported_modules)
135         {
136             m_persistent_vars.AddHandLoadedClangModule(module);
137         }
138     }
139 
140     bool hasErrors()
141     {
142         return m_has_errors;
143     }
144 
145     const std::string &getErrorString()
146     {
147         return m_error_stream.GetString();
148     }
149 };
150 
151 //===----------------------------------------------------------------------===//
152 // Implementation of ClangExpressionParser
153 //===----------------------------------------------------------------------===//
154 
155 ClangExpressionParser::ClangExpressionParser (ExecutionContextScope *exe_scope,
156                                               Expression &expr,
157                                               bool generate_debug_info) :
158     ExpressionParser (exe_scope, expr, generate_debug_info),
159     m_compiler (),
160     m_code_generator (),
161     m_pp_callbacks(nullptr)
162 {
163     // 1. Create a new compiler instance.
164     m_compiler.reset(new CompilerInstance());
165 
166     // 2. Install the target.
167 
168     lldb::TargetSP target_sp;
169     if (exe_scope)
170         target_sp = exe_scope->CalculateTarget();
171 
172     // TODO: figure out what to really do when we don't have a valid target.
173     // Sometimes this will be ok to just use the host target triple (when we
174     // evaluate say "2+3", but other expressions like breakpoint conditions
175     // and other things that _are_ target specific really shouldn't just be
176     // using the host triple. This needs to be fixed in a better way.
177     if (target_sp && target_sp->GetArchitecture().IsValid())
178     {
179         std::string triple = target_sp->GetArchitecture().GetTriple().str();
180         m_compiler->getTargetOpts().Triple = triple;
181     }
182     else
183     {
184         m_compiler->getTargetOpts().Triple = llvm::sys::getDefaultTargetTriple();
185     }
186 
187     if (target_sp->GetArchitecture().GetMachine() == llvm::Triple::x86 ||
188         target_sp->GetArchitecture().GetMachine() == llvm::Triple::x86_64)
189     {
190         m_compiler->getTargetOpts().Features.push_back("+sse");
191         m_compiler->getTargetOpts().Features.push_back("+sse2");
192     }
193 
194     // Any arm32 iOS environment, but not on arm64
195     if (m_compiler->getTargetOpts().Triple.find("arm64") == std::string::npos &&
196         m_compiler->getTargetOpts().Triple.find("arm") != std::string::npos &&
197         m_compiler->getTargetOpts().Triple.find("ios") != std::string::npos)
198     {
199         m_compiler->getTargetOpts().ABI = "apcs-gnu";
200     }
201 
202     m_compiler->createDiagnostics();
203 
204     // Create the target instance.
205     m_compiler->setTarget(TargetInfo::CreateTargetInfo(
206         m_compiler->getDiagnostics(), m_compiler->getInvocation().TargetOpts));
207 
208     assert (m_compiler->hasTarget());
209 
210     // 3. Set options.
211 
212     lldb::LanguageType language = expr.Language();
213 
214     switch (language)
215     {
216     case lldb::eLanguageTypeC:
217     case lldb::eLanguageTypeC89:
218     case lldb::eLanguageTypeC99:
219     case lldb::eLanguageTypeC11:
220         // FIXME: the following language option is a temporary workaround,
221         // to "ask for C, get C++."
222         // For now, the expression parser must use C++ anytime the
223         // language is a C family language, because the expression parser
224         // uses features of C++ to capture values.
225         m_compiler->getLangOpts().CPlusPlus = true;
226         break;
227     case lldb::eLanguageTypeObjC:
228         m_compiler->getLangOpts().ObjC1 = true;
229         m_compiler->getLangOpts().ObjC2 = true;
230         // FIXME: the following language option is a temporary workaround,
231         // to "ask for ObjC, get ObjC++" (see comment above).
232         m_compiler->getLangOpts().CPlusPlus = true;
233         break;
234     case lldb::eLanguageTypeC_plus_plus:
235     case lldb::eLanguageTypeC_plus_plus_11:
236     case lldb::eLanguageTypeC_plus_plus_14:
237         m_compiler->getLangOpts().CPlusPlus11 = true;
238         m_compiler->getHeaderSearchOpts().UseLibcxx = true;
239         // fall thru ...
240     case lldb::eLanguageTypeC_plus_plus_03:
241         m_compiler->getLangOpts().CPlusPlus = true;
242         // FIXME: the following language option is a temporary workaround,
243         // to "ask for C++, get ObjC++".  Apple hopes to remove this requirement
244         // on non-Apple platforms, but for now it is needed.
245         m_compiler->getLangOpts().ObjC1 = true;
246         break;
247     case lldb::eLanguageTypeObjC_plus_plus:
248     case lldb::eLanguageTypeUnknown:
249     default:
250         m_compiler->getLangOpts().ObjC1 = true;
251         m_compiler->getLangOpts().ObjC2 = true;
252         m_compiler->getLangOpts().CPlusPlus = true;
253         m_compiler->getLangOpts().CPlusPlus11 = true;
254         m_compiler->getHeaderSearchOpts().UseLibcxx = true;
255         break;
256     }
257 
258     m_compiler->getLangOpts().Bool = true;
259     m_compiler->getLangOpts().WChar = true;
260     m_compiler->getLangOpts().Blocks = true;
261     m_compiler->getLangOpts().DebuggerSupport = true; // Features specifically for debugger clients
262     if (expr.DesiredResultType() == Expression::eResultTypeId)
263         m_compiler->getLangOpts().DebuggerCastResultToId = true;
264 
265     m_compiler->getLangOpts().CharIsSigned =
266             ArchSpec(m_compiler->getTargetOpts().Triple.c_str()).CharIsSignedByDefault();
267 
268     // Spell checking is a nice feature, but it ends up completing a
269     // lot of types that we didn't strictly speaking need to complete.
270     // As a result, we spend a long time parsing and importing debug
271     // information.
272     m_compiler->getLangOpts().SpellChecking = false;
273 
274     lldb::ProcessSP process_sp;
275     if (exe_scope)
276         process_sp = exe_scope->CalculateProcess();
277 
278     if (process_sp && m_compiler->getLangOpts().ObjC1)
279     {
280         if (process_sp->GetObjCLanguageRuntime())
281         {
282             if (process_sp->GetObjCLanguageRuntime()->GetRuntimeVersion() == ObjCLanguageRuntime::ObjCRuntimeVersions::eAppleObjC_V2)
283                 m_compiler->getLangOpts().ObjCRuntime.set(ObjCRuntime::MacOSX, VersionTuple(10, 7));
284             else
285                 m_compiler->getLangOpts().ObjCRuntime.set(ObjCRuntime::FragileMacOSX, VersionTuple(10, 7));
286 
287             if (process_sp->GetObjCLanguageRuntime()->HasNewLiteralsAndIndexing())
288                 m_compiler->getLangOpts().DebuggerObjCLiteral = true;
289         }
290     }
291 
292     m_compiler->getLangOpts().ThreadsafeStatics = false;
293     m_compiler->getLangOpts().AccessControl = false; // Debuggers get universal access
294     m_compiler->getLangOpts().DollarIdents = true; // $ indicates a persistent variable name
295 
296     // Set CodeGen options
297     m_compiler->getCodeGenOpts().EmitDeclMetadata = true;
298     m_compiler->getCodeGenOpts().InstrumentFunctions = false;
299     m_compiler->getCodeGenOpts().DisableFPElim = true;
300     m_compiler->getCodeGenOpts().OmitLeafFramePointer = false;
301     if (generate_debug_info)
302         m_compiler->getCodeGenOpts().setDebugInfo(CodeGenOptions::FullDebugInfo);
303     else
304         m_compiler->getCodeGenOpts().setDebugInfo(CodeGenOptions::NoDebugInfo);
305 
306     // Disable some warnings.
307     m_compiler->getDiagnostics().setSeverityForGroup(clang::diag::Flavor::WarningOrError,
308         "unused-value", clang::diag::Severity::Ignored, SourceLocation());
309     m_compiler->getDiagnostics().setSeverityForGroup(clang::diag::Flavor::WarningOrError,
310         "odr", clang::diag::Severity::Ignored, SourceLocation());
311 
312     // Inform the target of the language options
313     //
314     // FIXME: We shouldn't need to do this, the target should be immutable once
315     // created. This complexity should be lifted elsewhere.
316     m_compiler->getTarget().adjust(m_compiler->getLangOpts());
317 
318     // 4. Set up the diagnostic buffer for reporting errors
319 
320     m_compiler->getDiagnostics().setClient(new clang::TextDiagnosticBuffer);
321 
322     // 5. Set up the source management objects inside the compiler
323 
324     clang::FileSystemOptions file_system_options;
325     m_file_manager.reset(new clang::FileManager(file_system_options));
326 
327     if (!m_compiler->hasSourceManager())
328         m_compiler->createSourceManager(*m_file_manager.get());
329 
330     m_compiler->createFileManager();
331     m_compiler->createPreprocessor(TU_Complete);
332 
333     if (ClangModulesDeclVendor *decl_vendor = target_sp->GetClangModulesDeclVendor())
334     {
335         ClangPersistentVariables *clang_persistent_vars = llvm::cast<ClangPersistentVariables>(target_sp->GetPersistentExpressionStateForLanguage(lldb::eLanguageTypeC));
336         std::unique_ptr<PPCallbacks> pp_callbacks(new LLDBPreprocessorCallbacks(*decl_vendor, *clang_persistent_vars));
337         m_pp_callbacks = static_cast<LLDBPreprocessorCallbacks*>(pp_callbacks.get());
338         m_compiler->getPreprocessor().addPPCallbacks(std::move(pp_callbacks));
339     }
340 
341     // 6. Most of this we get from the CompilerInstance, but we
342     // also want to give the context an ExternalASTSource.
343     m_selector_table.reset(new SelectorTable());
344     m_builtin_context.reset(new Builtin::Context());
345 
346     std::unique_ptr<clang::ASTContext> ast_context(new ASTContext(m_compiler->getLangOpts(),
347                                                                   m_compiler->getSourceManager(),
348                                                                   m_compiler->getPreprocessor().getIdentifierTable(),
349                                                                   *m_selector_table.get(),
350                                                                   *m_builtin_context.get()));
351 
352     ast_context->InitBuiltinTypes(m_compiler->getTarget());
353 
354     ClangExpressionHelper *type_system_helper = dyn_cast<ClangExpressionHelper>(m_expr.GetTypeSystemHelper());
355     ClangExpressionDeclMap *decl_map = type_system_helper->DeclMap();
356 
357     if (decl_map)
358     {
359         llvm::IntrusiveRefCntPtr<clang::ExternalASTSource> ast_source(decl_map->CreateProxy());
360         decl_map->InstallASTContext(ast_context.get());
361         ast_context->setExternalSource(ast_source);
362     }
363 
364     m_ast_context.reset(new ClangASTContext(m_compiler->getTargetOpts().Triple.c_str()));
365     m_ast_context->setASTContext(ast_context.get());
366     m_compiler->setASTContext(ast_context.release());
367 
368     std::string module_name("$__lldb_module");
369 
370     m_llvm_context.reset(new LLVMContext());
371     m_code_generator.reset(CreateLLVMCodeGen(m_compiler->getDiagnostics(),
372                                              module_name,
373                                              m_compiler->getHeaderSearchOpts(),
374                                              m_compiler->getPreprocessorOpts(),
375                                              m_compiler->getCodeGenOpts(),
376                                              *m_llvm_context));
377 }
378 
379 ClangExpressionParser::~ClangExpressionParser()
380 {
381 }
382 
383 unsigned
384 ClangExpressionParser::Parse (Stream &stream)
385 {
386     TextDiagnosticBuffer *diag_buf = static_cast<TextDiagnosticBuffer*>(m_compiler->getDiagnostics().getClient());
387 
388     diag_buf->FlushDiagnostics (m_compiler->getDiagnostics());
389 
390     const char *expr_text = m_expr.Text();
391 
392     clang::SourceManager &SourceMgr = m_compiler->getSourceManager();
393     bool created_main_file = false;
394     if (m_compiler->getCodeGenOpts().getDebugInfo() == CodeGenOptions::FullDebugInfo)
395     {
396         std::string temp_source_path;
397 
398         int temp_fd = -1;
399         llvm::SmallString<PATH_MAX> result_path;
400         FileSpec tmpdir_file_spec;
401         if (HostInfo::GetLLDBPath(lldb::ePathTypeLLDBTempSystemDir, tmpdir_file_spec))
402         {
403             tmpdir_file_spec.AppendPathComponent("lldb-%%%%%%.expr");
404             temp_source_path = tmpdir_file_spec.GetPath();
405             llvm::sys::fs::createUniqueFile(temp_source_path, temp_fd, result_path);
406         }
407         else
408         {
409             llvm::sys::fs::createTemporaryFile("lldb", "expr", temp_fd, result_path);
410         }
411 
412         if (temp_fd != -1)
413         {
414             lldb_private::File file (temp_fd, true);
415             const size_t expr_text_len = strlen(expr_text);
416             size_t bytes_written = expr_text_len;
417             if (file.Write(expr_text, bytes_written).Success())
418             {
419                 if (bytes_written == expr_text_len)
420                 {
421                     file.Close();
422                     SourceMgr.setMainFileID(SourceMgr.createFileID(
423                         m_file_manager->getFile(result_path),
424                         SourceLocation(), SrcMgr::C_User));
425                     created_main_file = true;
426                 }
427             }
428         }
429     }
430 
431     if (!created_main_file)
432     {
433         std::unique_ptr<MemoryBuffer> memory_buffer = MemoryBuffer::getMemBufferCopy(expr_text, __FUNCTION__);
434         SourceMgr.setMainFileID(SourceMgr.createFileID(std::move(memory_buffer)));
435     }
436 
437     diag_buf->BeginSourceFile(m_compiler->getLangOpts(), &m_compiler->getPreprocessor());
438 
439     ClangExpressionHelper *type_system_helper = dyn_cast<ClangExpressionHelper>(m_expr.GetTypeSystemHelper());
440 
441     ASTConsumer *ast_transformer = type_system_helper->ASTTransformer(m_code_generator.get());
442 
443     if (ClangExpressionDeclMap *decl_map = type_system_helper->DeclMap())
444         decl_map->InstallCodeGenerator(m_code_generator.get());
445 
446     if (ast_transformer)
447     {
448         ast_transformer->Initialize(m_compiler->getASTContext());
449         ParseAST(m_compiler->getPreprocessor(), ast_transformer, m_compiler->getASTContext());
450     }
451     else
452     {
453         m_code_generator->Initialize(m_compiler->getASTContext());
454         ParseAST(m_compiler->getPreprocessor(), m_code_generator.get(), m_compiler->getASTContext());
455     }
456 
457     diag_buf->EndSourceFile();
458 
459     TextDiagnosticBuffer::const_iterator diag_iterator;
460 
461     int num_errors = 0;
462 
463     if (m_pp_callbacks && m_pp_callbacks->hasErrors())
464     {
465         num_errors++;
466 
467         stream.PutCString(m_pp_callbacks->getErrorString().c_str());
468     }
469 
470     for (diag_iterator = diag_buf->warn_begin();
471          diag_iterator != diag_buf->warn_end();
472          ++diag_iterator)
473         stream.Printf("warning: %s\n", (*diag_iterator).second.c_str());
474 
475     for (diag_iterator = diag_buf->err_begin();
476          diag_iterator != diag_buf->err_end();
477          ++diag_iterator)
478     {
479         num_errors++;
480         stream.Printf("error: %s\n", (*diag_iterator).second.c_str());
481     }
482 
483     for (diag_iterator = diag_buf->note_begin();
484          diag_iterator != diag_buf->note_end();
485          ++diag_iterator)
486         stream.Printf("note: %s\n", (*diag_iterator).second.c_str());
487 
488     if (!num_errors)
489     {
490         if (type_system_helper->DeclMap() && !type_system_helper->DeclMap()->ResolveUnknownTypes())
491         {
492             stream.Printf("error: Couldn't infer the type of a variable\n");
493             num_errors++;
494         }
495     }
496 
497     return num_errors;
498 }
499 
500 static bool FindFunctionInModule (ConstString &mangled_name,
501                                   llvm::Module *module,
502                                   const char *orig_name)
503 {
504     for (llvm::Module::iterator fi = module->getFunctionList().begin(), fe = module->getFunctionList().end();
505          fi != fe;
506          ++fi)
507     {
508         if (fi->getName().str().find(orig_name) != std::string::npos)
509         {
510             mangled_name.SetCString(fi->getName().str().c_str());
511             return true;
512         }
513     }
514 
515     return false;
516 }
517 
518 Error
519 ClangExpressionParser::PrepareForExecution (lldb::addr_t &func_addr,
520                                             lldb::addr_t &func_end,
521                                             std::shared_ptr<IRExecutionUnit> &execution_unit_sp,
522                                             ExecutionContext &exe_ctx,
523                                             bool &can_interpret,
524                                             ExecutionPolicy execution_policy)
525 {
526 	func_addr = LLDB_INVALID_ADDRESS;
527 	func_end = LLDB_INVALID_ADDRESS;
528     Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
529 
530     Error err;
531 
532     std::unique_ptr<llvm::Module> llvm_module_ap (m_code_generator->ReleaseModule());
533 
534     if (!llvm_module_ap.get())
535     {
536         err.SetErrorToGenericError();
537         err.SetErrorString("IR doesn't contain a module");
538         return err;
539     }
540 
541     // Find the actual name of the function (it's often mangled somehow)
542 
543     ConstString function_name;
544 
545     if (!FindFunctionInModule(function_name, llvm_module_ap.get(), m_expr.FunctionName()))
546     {
547         err.SetErrorToGenericError();
548         err.SetErrorStringWithFormat("Couldn't find %s() in the module", m_expr.FunctionName());
549         return err;
550     }
551     else
552     {
553         if (log)
554             log->Printf("Found function %s for %s", function_name.AsCString(), m_expr.FunctionName());
555     }
556 
557     execution_unit_sp.reset(new IRExecutionUnit (m_llvm_context, // handed off here
558                                                  llvm_module_ap, // handed off here
559                                                  function_name,
560                                                  exe_ctx.GetTargetSP(),
561                                                  m_compiler->getTargetOpts().Features));
562 
563     ClangExpressionHelper *type_system_helper = dyn_cast<ClangExpressionHelper>(m_expr.GetTypeSystemHelper());
564     ClangExpressionDeclMap *decl_map = type_system_helper->DeclMap(); // result can be NULL
565 
566     if (decl_map)
567     {
568         Stream *error_stream = NULL;
569         Target *target = exe_ctx.GetTargetPtr();
570         if (target)
571             error_stream = target->GetDebugger().GetErrorFile().get();
572 
573         IRForTarget ir_for_target(decl_map,
574                                   m_expr.NeedsVariableResolution(),
575                                   *execution_unit_sp,
576                                   error_stream,
577                                   function_name.AsCString());
578 
579         bool ir_can_run = ir_for_target.runOnModule(*execution_unit_sp->GetModule());
580 
581         Error interpret_error;
582         Process *process = exe_ctx.GetProcessPtr();
583 
584         bool interpret_function_calls = !process ? false : process->CanInterpretFunctionCalls();
585         can_interpret = IRInterpreter::CanInterpret(*execution_unit_sp->GetModule(), *execution_unit_sp->GetFunction(), interpret_error, interpret_function_calls);
586 
587 
588         if (!ir_can_run)
589         {
590             err.SetErrorString("The expression could not be prepared to run in the target");
591             return err;
592         }
593 
594         if (!can_interpret && execution_policy == eExecutionPolicyNever)
595         {
596             err.SetErrorStringWithFormat("Can't run the expression locally: %s", interpret_error.AsCString());
597             return err;
598         }
599 
600         if (!process && execution_policy == eExecutionPolicyAlways)
601         {
602             err.SetErrorString("Expression needed to run in the target, but the target can't be run");
603             return err;
604         }
605 
606         if (execution_policy == eExecutionPolicyAlways || !can_interpret)
607         {
608             if (m_expr.NeedsValidation() && process)
609             {
610                 if (!process->GetDynamicCheckers())
611                 {
612                     DynamicCheckerFunctions *dynamic_checkers = new DynamicCheckerFunctions();
613 
614                     StreamString install_errors;
615 
616                     if (!dynamic_checkers->Install(install_errors, exe_ctx))
617                     {
618                         if (install_errors.GetString().empty())
619                             err.SetErrorString ("couldn't install checkers, unknown error");
620                         else
621                             err.SetErrorString (install_errors.GetString().c_str());
622 
623                         return err;
624                     }
625 
626                     process->SetDynamicCheckers(dynamic_checkers);
627 
628                     if (log)
629                         log->Printf("== [ClangUserExpression::Evaluate] Finished installing dynamic checkers ==");
630                 }
631 
632                 IRDynamicChecks ir_dynamic_checks(*process->GetDynamicCheckers(), function_name.AsCString());
633 
634                 if (!ir_dynamic_checks.runOnModule(*execution_unit_sp->GetModule()))
635                 {
636                     err.SetErrorToGenericError();
637                     err.SetErrorString("Couldn't add dynamic checks to the expression");
638                     return err;
639                 }
640             }
641 
642             execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);
643         }
644     }
645     else
646     {
647         execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);
648     }
649 
650     return err;
651 }
652