1 //===-- ClangExpressionParser.cpp -------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "clang/AST/ASTContext.h"
10 #include "clang/AST/ASTDiagnostic.h"
11 #include "clang/AST/ExternalASTSource.h"
12 #include "clang/AST/PrettyPrinter.h"
13 #include "clang/Basic/DiagnosticIDs.h"
14 #include "clang/Basic/SourceLocation.h"
15 #include "clang/Basic/TargetInfo.h"
16 #include "clang/Basic/Version.h"
17 #include "clang/CodeGen/CodeGenAction.h"
18 #include "clang/CodeGen/ModuleBuilder.h"
19 #include "clang/Edit/Commit.h"
20 #include "clang/Edit/EditedSource.h"
21 #include "clang/Edit/EditsReceiver.h"
22 #include "clang/Frontend/CompilerInstance.h"
23 #include "clang/Frontend/CompilerInvocation.h"
24 #include "clang/Frontend/FrontendActions.h"
25 #include "clang/Frontend/FrontendDiagnostic.h"
26 #include "clang/Frontend/FrontendPluginRegistry.h"
27 #include "clang/Frontend/TextDiagnosticBuffer.h"
28 #include "clang/Frontend/TextDiagnosticPrinter.h"
29 #include "clang/Lex/Preprocessor.h"
30 #include "clang/Parse/ParseAST.h"
31 #include "clang/Rewrite/Core/Rewriter.h"
32 #include "clang/Rewrite/Frontend/FrontendActions.h"
33 #include "clang/Sema/CodeCompleteConsumer.h"
34 #include "clang/Sema/Sema.h"
35 #include "clang/Sema/SemaConsumer.h"
36 
37 #include "llvm/ADT/StringRef.h"
38 #include "llvm/ExecutionEngine/ExecutionEngine.h"
39 #include "llvm/Support/CrashRecoveryContext.h"
40 #include "llvm/Support/Debug.h"
41 #include "llvm/Support/FileSystem.h"
42 #include "llvm/Support/TargetSelect.h"
43 
44 #include "llvm/IR/LLVMContext.h"
45 #include "llvm/IR/Module.h"
46 #include "llvm/Support/DynamicLibrary.h"
47 #include "llvm/Support/ErrorHandling.h"
48 #include "llvm/Support/Host.h"
49 #include "llvm/Support/MemoryBuffer.h"
50 #include "llvm/Support/Signals.h"
51 
52 #include "ClangDiagnostic.h"
53 #include "ClangExpressionParser.h"
54 #include "ClangUserExpression.h"
55 
56 #include "ASTUtils.h"
57 #include "ClangASTSource.h"
58 #include "ClangDiagnostic.h"
59 #include "ClangExpressionDeclMap.h"
60 #include "ClangExpressionHelper.h"
61 #include "ClangExpressionParser.h"
62 #include "ClangHost.h"
63 #include "ClangModulesDeclVendor.h"
64 #include "ClangPersistentVariables.h"
65 #include "IRDynamicChecks.h"
66 #include "IRForTarget.h"
67 #include "ModuleDependencyCollector.h"
68 
69 #include "lldb/Core/Debugger.h"
70 #include "lldb/Core/Disassembler.h"
71 #include "lldb/Core/Module.h"
72 #include "lldb/Core/StreamFile.h"
73 #include "lldb/Expression/IRExecutionUnit.h"
74 #include "lldb/Expression/IRInterpreter.h"
75 #include "lldb/Host/File.h"
76 #include "lldb/Host/HostInfo.h"
77 #include "lldb/Symbol/ClangASTContext.h"
78 #include "lldb/Symbol/SymbolVendor.h"
79 #include "lldb/Target/ExecutionContext.h"
80 #include "lldb/Target/Language.h"
81 #include "lldb/Target/Process.h"
82 #include "lldb/Target/Target.h"
83 #include "lldb/Target/ThreadPlanCallFunction.h"
84 #include "lldb/Utility/DataBufferHeap.h"
85 #include "lldb/Utility/LLDBAssert.h"
86 #include "lldb/Utility/Log.h"
87 #include "lldb/Utility/Reproducer.h"
88 #include "lldb/Utility/Stream.h"
89 #include "lldb/Utility/StreamString.h"
90 #include "lldb/Utility/StringList.h"
91 
92 #include "Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h"
93 
94 #include <cctype>
95 #include <memory>
96 
97 using namespace clang;
98 using namespace llvm;
99 using namespace lldb_private;
100 
101 //===----------------------------------------------------------------------===//
102 // Utility Methods for Clang
103 //===----------------------------------------------------------------------===//
104 
105 class ClangExpressionParser::LLDBPreprocessorCallbacks : public PPCallbacks {
106   ClangModulesDeclVendor &m_decl_vendor;
107   ClangPersistentVariables &m_persistent_vars;
108   StreamString m_error_stream;
109   bool m_has_errors = false;
110 
111 public:
112   LLDBPreprocessorCallbacks(ClangModulesDeclVendor &decl_vendor,
113                             ClangPersistentVariables &persistent_vars)
114       : m_decl_vendor(decl_vendor), m_persistent_vars(persistent_vars) {}
115 
116   void moduleImport(SourceLocation import_location, clang::ModuleIdPath path,
117                     const clang::Module * /*null*/) override {
118     SourceModule module;
119 
120     for (const std::pair<IdentifierInfo *, SourceLocation> &component : path)
121       module.path.push_back(ConstString(component.first->getName()));
122 
123     StreamString error_stream;
124 
125     ClangModulesDeclVendor::ModuleVector exported_modules;
126     if (!m_decl_vendor.AddModule(module, &exported_modules, m_error_stream))
127       m_has_errors = true;
128 
129     for (ClangModulesDeclVendor::ModuleID module : exported_modules)
130       m_persistent_vars.AddHandLoadedClangModule(module);
131   }
132 
133   bool hasErrors() { return m_has_errors; }
134 
135   llvm::StringRef getErrorString() { return m_error_stream.GetString(); }
136 };
137 
138 class ClangDiagnosticManagerAdapter : public clang::DiagnosticConsumer {
139 public:
140   ClangDiagnosticManagerAdapter(DiagnosticOptions &opts) {
141     DiagnosticOptions *m_options = new DiagnosticOptions(opts);
142     m_options->ShowPresumedLoc = true;
143     m_options->ShowLevel = false;
144     m_os.reset(new llvm::raw_string_ostream(m_output));
145     m_passthrough.reset(
146         new clang::TextDiagnosticPrinter(*m_os, m_options, false));
147   }
148 
149   void ResetManager(DiagnosticManager *manager = nullptr) {
150     m_manager = manager;
151   }
152 
153   void HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
154                         const clang::Diagnostic &Info) override {
155     // Render diagnostic message to m_output.
156     m_output.clear();
157     m_passthrough->HandleDiagnostic(DiagLevel, Info);
158     m_os->flush();
159 
160     if (m_manager) {
161       lldb_private::DiagnosticSeverity severity;
162       bool make_new_diagnostic = true;
163 
164       switch (DiagLevel) {
165       case DiagnosticsEngine::Level::Fatal:
166       case DiagnosticsEngine::Level::Error:
167         severity = eDiagnosticSeverityError;
168         break;
169       case DiagnosticsEngine::Level::Warning:
170         severity = eDiagnosticSeverityWarning;
171         break;
172       case DiagnosticsEngine::Level::Remark:
173       case DiagnosticsEngine::Level::Ignored:
174         severity = eDiagnosticSeverityRemark;
175         break;
176       case DiagnosticsEngine::Level::Note:
177         m_manager->AppendMessageToDiagnostic(m_output);
178         make_new_diagnostic = false;
179       }
180       if (make_new_diagnostic) {
181         // ClangDiagnostic messages are expected to have no whitespace/newlines
182         // around them.
183         std::string stripped_output = llvm::StringRef(m_output).trim();
184 
185         ClangDiagnostic *new_diagnostic =
186             new ClangDiagnostic(stripped_output, severity, Info.getID());
187         m_manager->AddDiagnostic(new_diagnostic);
188 
189         // Don't store away warning fixits, since the compiler doesn't have
190         // enough context in an expression for the warning to be useful.
191         // FIXME: Should we try to filter out FixIts that apply to our generated
192         // code, and not the user's expression?
193         if (severity == eDiagnosticSeverityError) {
194           size_t num_fixit_hints = Info.getNumFixItHints();
195           for (size_t i = 0; i < num_fixit_hints; i++) {
196             const clang::FixItHint &fixit = Info.getFixItHint(i);
197             if (!fixit.isNull())
198               new_diagnostic->AddFixitHint(fixit);
199           }
200         }
201       }
202     }
203   }
204 
205   clang::TextDiagnosticPrinter *GetPassthrough() { return m_passthrough.get(); }
206 
207 private:
208   DiagnosticManager *m_manager = nullptr;
209   std::shared_ptr<clang::TextDiagnosticPrinter> m_passthrough;
210   /// Output stream of m_passthrough.
211   std::shared_ptr<llvm::raw_string_ostream> m_os;
212   /// Output string filled by m_os.
213   std::string m_output;
214 };
215 
216 static void SetupModuleHeaderPaths(CompilerInstance *compiler,
217                                    std::vector<std::string> include_directories,
218                                    lldb::TargetSP target_sp) {
219   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
220 
221   HeaderSearchOptions &search_opts = compiler->getHeaderSearchOpts();
222 
223   for (const std::string &dir : include_directories) {
224     search_opts.AddPath(dir, frontend::System, false, true);
225     LLDB_LOG(log, "Added user include dir: {0}", dir);
226   }
227 
228   llvm::SmallString<128> module_cache;
229   auto props = ModuleList::GetGlobalModuleListProperties();
230   props.GetClangModulesCachePath().GetPath(module_cache);
231   search_opts.ModuleCachePath = module_cache.str();
232   LLDB_LOG(log, "Using module cache path: {0}", module_cache.c_str());
233 
234   FileSpec clang_resource_dir = GetClangResourceDir();
235   std::string resource_dir = clang_resource_dir.GetPath();
236   if (FileSystem::Instance().IsDirectory(resource_dir)) {
237     search_opts.ResourceDir = resource_dir;
238     std::string resource_include = resource_dir + "/include";
239     search_opts.AddPath(resource_include, frontend::System, false, true);
240 
241     LLDB_LOG(log, "Added resource include dir: {0}", resource_include);
242   }
243 
244   search_opts.ImplicitModuleMaps = true;
245 
246   std::vector<std::string> system_include_directories =
247       target_sp->GetPlatform()->GetSystemIncludeDirectories(
248           lldb::eLanguageTypeC_plus_plus);
249 
250   for (const std::string &include_dir : system_include_directories) {
251     search_opts.AddPath(include_dir, frontend::System, false, true);
252 
253     LLDB_LOG(log, "Added system include dir: {0}", include_dir);
254   }
255 }
256 
257 //===----------------------------------------------------------------------===//
258 // Implementation of ClangExpressionParser
259 //===----------------------------------------------------------------------===//
260 
261 ClangExpressionParser::ClangExpressionParser(ExecutionContextScope *exe_scope, Expression &expr,
262     bool generate_debug_info, std::vector<std::string> include_directories, std::string filename)
263     : ExpressionParser(exe_scope, expr, generate_debug_info), m_compiler(),
264       m_pp_callbacks(nullptr),
265       m_include_directories(std::move(include_directories)), m_filename(std::move(filename)) {
266   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
267 
268   // We can't compile expressions without a target.  So if the exe_scope is
269   // null or doesn't have a target, then we just need to get out of here.  I'll
270   // lldb_assert and not make any of the compiler objects since
271   // I can't return errors directly from the constructor.  Further calls will
272   // check if the compiler was made and
273   // bag out if it wasn't.
274 
275   if (!exe_scope) {
276     lldb_assert(exe_scope, "Can't make an expression parser with a null scope.",
277                 __FUNCTION__, __FILE__, __LINE__);
278     return;
279   }
280 
281   lldb::TargetSP target_sp;
282   target_sp = exe_scope->CalculateTarget();
283   if (!target_sp) {
284     lldb_assert(target_sp.get(),
285                 "Can't make an expression parser with a null target.",
286                 __FUNCTION__, __FILE__, __LINE__);
287     return;
288   }
289 
290   // 1. Create a new compiler instance.
291   m_compiler.reset(new CompilerInstance());
292 
293   // When capturing a reproducer, hook up the file collector with clang to
294   // collector modules and headers.
295   if (repro::Generator *g = repro::Reproducer::Instance().GetGenerator()) {
296     repro::FileProvider &fp = g->GetOrCreate<repro::FileProvider>();
297     m_compiler->setModuleDepCollector(
298         std::make_shared<ModuleDependencyCollectorAdaptor>(
299             fp.GetFileCollector()));
300     DependencyOutputOptions &opts = m_compiler->getDependencyOutputOpts();
301     opts.IncludeSystemHeaders = true;
302     opts.IncludeModuleFiles = true;
303   }
304 
305   // Make sure clang uses the same VFS as LLDB.
306   m_compiler->createFileManager(FileSystem::Instance().GetVirtualFileSystem());
307 
308   lldb::LanguageType frame_lang =
309       expr.Language(); // defaults to lldb::eLanguageTypeUnknown
310   bool overridden_target_opts = false;
311   lldb_private::LanguageRuntime *lang_rt = nullptr;
312 
313   std::string abi;
314   ArchSpec target_arch;
315   target_arch = target_sp->GetArchitecture();
316 
317   const auto target_machine = target_arch.GetMachine();
318 
319   // If the expression is being evaluated in the context of an existing stack
320   // frame, we introspect to see if the language runtime is available.
321 
322   lldb::StackFrameSP frame_sp = exe_scope->CalculateStackFrame();
323   lldb::ProcessSP process_sp = exe_scope->CalculateProcess();
324 
325   // Make sure the user hasn't provided a preferred execution language with
326   // `expression --language X -- ...`
327   if (frame_sp && frame_lang == lldb::eLanguageTypeUnknown)
328     frame_lang = frame_sp->GetLanguage();
329 
330   if (process_sp && frame_lang != lldb::eLanguageTypeUnknown) {
331     lang_rt = process_sp->GetLanguageRuntime(frame_lang);
332     LLDB_LOGF(log, "Frame has language of type %s",
333               Language::GetNameForLanguageType(frame_lang));
334   }
335 
336   // 2. Configure the compiler with a set of default options that are
337   // appropriate for most situations.
338   if (target_arch.IsValid()) {
339     std::string triple = target_arch.GetTriple().str();
340     m_compiler->getTargetOpts().Triple = triple;
341     LLDB_LOGF(log, "Using %s as the target triple",
342               m_compiler->getTargetOpts().Triple.c_str());
343   } else {
344     // If we get here we don't have a valid target and just have to guess.
345     // Sometimes this will be ok to just use the host target triple (when we
346     // evaluate say "2+3", but other expressions like breakpoint conditions and
347     // other things that _are_ target specific really shouldn't just be using
348     // the host triple. In such a case the language runtime should expose an
349     // overridden options set (3), below.
350     m_compiler->getTargetOpts().Triple = llvm::sys::getDefaultTargetTriple();
351     LLDB_LOGF(log, "Using default target triple of %s",
352               m_compiler->getTargetOpts().Triple.c_str());
353   }
354   // Now add some special fixes for known architectures: Any arm32 iOS
355   // environment, but not on arm64
356   if (m_compiler->getTargetOpts().Triple.find("arm64") == std::string::npos &&
357       m_compiler->getTargetOpts().Triple.find("arm") != std::string::npos &&
358       m_compiler->getTargetOpts().Triple.find("ios") != std::string::npos) {
359     m_compiler->getTargetOpts().ABI = "apcs-gnu";
360   }
361   // Supported subsets of x86
362   if (target_machine == llvm::Triple::x86 ||
363       target_machine == llvm::Triple::x86_64) {
364     m_compiler->getTargetOpts().Features.push_back("+sse");
365     m_compiler->getTargetOpts().Features.push_back("+sse2");
366   }
367 
368   // Set the target CPU to generate code for. This will be empty for any CPU
369   // that doesn't really need to make a special
370   // CPU string.
371   m_compiler->getTargetOpts().CPU = target_arch.GetClangTargetCPU();
372 
373   // Set the target ABI
374   abi = GetClangTargetABI(target_arch);
375   if (!abi.empty())
376     m_compiler->getTargetOpts().ABI = abi;
377 
378   // 3. Now allow the runtime to provide custom configuration options for the
379   // target. In this case, a specialized language runtime is available and we
380   // can query it for extra options. For 99% of use cases, this will not be
381   // needed and should be provided when basic platform detection is not enough.
382   if (lang_rt)
383     overridden_target_opts =
384         lang_rt->GetOverrideExprOptions(m_compiler->getTargetOpts());
385 
386   if (overridden_target_opts)
387     if (log && log->GetVerbose()) {
388       LLDB_LOGV(
389           log, "Using overridden target options for the expression evaluation");
390 
391       auto opts = m_compiler->getTargetOpts();
392       LLDB_LOGV(log, "Triple: '{0}'", opts.Triple);
393       LLDB_LOGV(log, "CPU: '{0}'", opts.CPU);
394       LLDB_LOGV(log, "FPMath: '{0}'", opts.FPMath);
395       LLDB_LOGV(log, "ABI: '{0}'", opts.ABI);
396       LLDB_LOGV(log, "LinkerVersion: '{0}'", opts.LinkerVersion);
397       StringList::LogDump(log, opts.FeaturesAsWritten, "FeaturesAsWritten");
398       StringList::LogDump(log, opts.Features, "Features");
399     }
400 
401   // 4. Create and install the target on the compiler.
402   m_compiler->createDiagnostics();
403   auto target_info = TargetInfo::CreateTargetInfo(
404       m_compiler->getDiagnostics(), m_compiler->getInvocation().TargetOpts);
405   if (log) {
406     LLDB_LOGF(log, "Using SIMD alignment: %d",
407               target_info->getSimdDefaultAlign());
408     LLDB_LOGF(log, "Target datalayout string: '%s'",
409               target_info->getDataLayout().getStringRepresentation().c_str());
410     LLDB_LOGF(log, "Target ABI: '%s'", target_info->getABI().str().c_str());
411     LLDB_LOGF(log, "Target vector alignment: %d",
412               target_info->getMaxVectorAlign());
413   }
414   m_compiler->setTarget(target_info);
415 
416   assert(m_compiler->hasTarget());
417 
418   // 5. Set language options.
419   lldb::LanguageType language = expr.Language();
420   LangOptions &lang_opts = m_compiler->getLangOpts();
421 
422   switch (language) {
423   case lldb::eLanguageTypeC:
424   case lldb::eLanguageTypeC89:
425   case lldb::eLanguageTypeC99:
426   case lldb::eLanguageTypeC11:
427     // FIXME: the following language option is a temporary workaround,
428     // to "ask for C, get C++."
429     // For now, the expression parser must use C++ anytime the language is a C
430     // family language, because the expression parser uses features of C++ to
431     // capture values.
432     lang_opts.CPlusPlus = true;
433     break;
434   case lldb::eLanguageTypeObjC:
435     lang_opts.ObjC = true;
436     // FIXME: the following language option is a temporary workaround,
437     // to "ask for ObjC, get ObjC++" (see comment above).
438     lang_opts.CPlusPlus = true;
439 
440     // Clang now sets as default C++14 as the default standard (with
441     // GNU extensions), so we do the same here to avoid mismatches that
442     // cause compiler error when evaluating expressions (e.g. nullptr not found
443     // as it's a C++11 feature). Currently lldb evaluates C++14 as C++11 (see
444     // two lines below) so we decide to be consistent with that, but this could
445     // be re-evaluated in the future.
446     lang_opts.CPlusPlus11 = true;
447     break;
448   case lldb::eLanguageTypeC_plus_plus:
449   case lldb::eLanguageTypeC_plus_plus_11:
450   case lldb::eLanguageTypeC_plus_plus_14:
451     lang_opts.CPlusPlus11 = true;
452     m_compiler->getHeaderSearchOpts().UseLibcxx = true;
453     LLVM_FALLTHROUGH;
454   case lldb::eLanguageTypeC_plus_plus_03:
455     lang_opts.CPlusPlus = true;
456     if (process_sp)
457       lang_opts.ObjC =
458           process_sp->GetLanguageRuntime(lldb::eLanguageTypeObjC) != nullptr;
459     break;
460   case lldb::eLanguageTypeObjC_plus_plus:
461   case lldb::eLanguageTypeUnknown:
462   default:
463     lang_opts.ObjC = true;
464     lang_opts.CPlusPlus = true;
465     lang_opts.CPlusPlus11 = true;
466     m_compiler->getHeaderSearchOpts().UseLibcxx = true;
467     break;
468   }
469 
470   lang_opts.Bool = true;
471   lang_opts.WChar = true;
472   lang_opts.Blocks = true;
473   lang_opts.DebuggerSupport =
474       true; // Features specifically for debugger clients
475   if (expr.DesiredResultType() == Expression::eResultTypeId)
476     lang_opts.DebuggerCastResultToId = true;
477 
478   lang_opts.CharIsSigned = ArchSpec(m_compiler->getTargetOpts().Triple.c_str())
479                                .CharIsSignedByDefault();
480 
481   // Spell checking is a nice feature, but it ends up completing a lot of types
482   // that we didn't strictly speaking need to complete. As a result, we spend a
483   // long time parsing and importing debug information.
484   lang_opts.SpellChecking = false;
485 
486   auto *clang_expr = dyn_cast<ClangUserExpression>(&m_expr);
487   if (clang_expr && clang_expr->DidImportCxxModules()) {
488     LLDB_LOG(log, "Adding lang options for importing C++ modules");
489 
490     lang_opts.Modules = true;
491     // We want to implicitly build modules.
492     lang_opts.ImplicitModules = true;
493     // To automatically import all submodules when we import 'std'.
494     lang_opts.ModulesLocalVisibility = false;
495 
496     // We use the @import statements, so we need this:
497     // FIXME: We could use the modules-ts, but that currently doesn't work.
498     lang_opts.ObjC = true;
499 
500     // Options we need to parse libc++ code successfully.
501     // FIXME: We should ask the driver for the appropriate default flags.
502     lang_opts.GNUMode = true;
503     lang_opts.GNUKeywords = true;
504     lang_opts.DoubleSquareBracketAttributes = true;
505     lang_opts.CPlusPlus11 = true;
506 
507     SetupModuleHeaderPaths(m_compiler.get(), m_include_directories,
508                            target_sp);
509   }
510 
511   if (process_sp && lang_opts.ObjC) {
512     if (auto *runtime = ObjCLanguageRuntime::Get(*process_sp)) {
513       if (runtime->GetRuntimeVersion() ==
514           ObjCLanguageRuntime::ObjCRuntimeVersions::eAppleObjC_V2)
515         lang_opts.ObjCRuntime.set(ObjCRuntime::MacOSX, VersionTuple(10, 7));
516       else
517         lang_opts.ObjCRuntime.set(ObjCRuntime::FragileMacOSX,
518                                   VersionTuple(10, 7));
519 
520       if (runtime->HasNewLiteralsAndIndexing())
521         lang_opts.DebuggerObjCLiteral = true;
522     }
523   }
524 
525   lang_opts.ThreadsafeStatics = false;
526   lang_opts.AccessControl = false; // Debuggers get universal access
527   lang_opts.DollarIdents = true;   // $ indicates a persistent variable name
528   // We enable all builtin functions beside the builtins from libc/libm (e.g.
529   // 'fopen'). Those libc functions are already correctly handled by LLDB, and
530   // additionally enabling them as expandable builtins is breaking Clang.
531   lang_opts.NoBuiltin = true;
532 
533   // Set CodeGen options
534   m_compiler->getCodeGenOpts().EmitDeclMetadata = true;
535   m_compiler->getCodeGenOpts().InstrumentFunctions = false;
536   m_compiler->getCodeGenOpts().setFramePointer(
537                                     CodeGenOptions::FramePointerKind::All);
538   if (generate_debug_info)
539     m_compiler->getCodeGenOpts().setDebugInfo(codegenoptions::FullDebugInfo);
540   else
541     m_compiler->getCodeGenOpts().setDebugInfo(codegenoptions::NoDebugInfo);
542 
543   // Disable some warnings.
544   m_compiler->getDiagnostics().setSeverityForGroup(
545       clang::diag::Flavor::WarningOrError, "unused-value",
546       clang::diag::Severity::Ignored, SourceLocation());
547   m_compiler->getDiagnostics().setSeverityForGroup(
548       clang::diag::Flavor::WarningOrError, "odr",
549       clang::diag::Severity::Ignored, SourceLocation());
550 
551   // Inform the target of the language options
552   //
553   // FIXME: We shouldn't need to do this, the target should be immutable once
554   // created. This complexity should be lifted elsewhere.
555   m_compiler->getTarget().adjust(m_compiler->getLangOpts());
556 
557   // 6. Set up the diagnostic buffer for reporting errors
558 
559   auto diag_mgr = new ClangDiagnosticManagerAdapter(
560       m_compiler->getDiagnostics().getDiagnosticOptions());
561   m_compiler->getDiagnostics().setClient(diag_mgr);
562 
563   // 7. Set up the source management objects inside the compiler
564   m_compiler->createFileManager();
565   if (!m_compiler->hasSourceManager())
566     m_compiler->createSourceManager(m_compiler->getFileManager());
567   m_compiler->createPreprocessor(TU_Complete);
568 
569   if (ClangModulesDeclVendor *decl_vendor =
570           target_sp->GetClangModulesDeclVendor()) {
571     ClangPersistentVariables *clang_persistent_vars =
572         llvm::cast<ClangPersistentVariables>(
573             target_sp->GetPersistentExpressionStateForLanguage(
574                 lldb::eLanguageTypeC));
575     std::unique_ptr<PPCallbacks> pp_callbacks(
576         new LLDBPreprocessorCallbacks(*decl_vendor, *clang_persistent_vars));
577     m_pp_callbacks =
578         static_cast<LLDBPreprocessorCallbacks *>(pp_callbacks.get());
579     m_compiler->getPreprocessor().addPPCallbacks(std::move(pp_callbacks));
580   }
581 
582   // 8. Most of this we get from the CompilerInstance, but we also want to give
583   // the context an ExternalASTSource.
584 
585   auto &PP = m_compiler->getPreprocessor();
586   auto &builtin_context = PP.getBuiltinInfo();
587   builtin_context.initializeBuiltins(PP.getIdentifierTable(),
588                                      m_compiler->getLangOpts());
589 
590   m_compiler->createASTContext();
591   clang::ASTContext &ast_context = m_compiler->getASTContext();
592 
593   m_ast_context.reset(
594       new ClangASTContext(m_compiler->getTargetOpts().Triple.c_str()));
595   m_ast_context->setASTContext(&ast_context);
596 
597   std::string module_name("$__lldb_module");
598 
599   m_llvm_context.reset(new LLVMContext());
600   m_code_generator.reset(CreateLLVMCodeGen(
601       m_compiler->getDiagnostics(), module_name,
602       m_compiler->getHeaderSearchOpts(), m_compiler->getPreprocessorOpts(),
603       m_compiler->getCodeGenOpts(), *m_llvm_context));
604 }
605 
606 ClangExpressionParser::~ClangExpressionParser() {}
607 
608 namespace {
609 
610 /// \class CodeComplete
611 ///
612 /// A code completion consumer for the clang Sema that is responsible for
613 /// creating the completion suggestions when a user requests completion
614 /// of an incomplete `expr` invocation.
615 class CodeComplete : public CodeCompleteConsumer {
616   CodeCompletionTUInfo m_info;
617 
618   std::string m_expr;
619   unsigned m_position = 0;
620   CompletionRequest &m_request;
621   /// The printing policy we use when printing declarations for our completion
622   /// descriptions.
623   clang::PrintingPolicy m_desc_policy;
624 
625   /// Returns true if the given character can be used in an identifier.
626   /// This also returns true for numbers because for completion we usually
627   /// just iterate backwards over iterators.
628   ///
629   /// Note: lldb uses '$' in its internal identifiers, so we also allow this.
630   static bool IsIdChar(char c) {
631     return c == '_' || std::isalnum(c) || c == '$';
632   }
633 
634   /// Returns true if the given character is used to separate arguments
635   /// in the command line of lldb.
636   static bool IsTokenSeparator(char c) { return c == ' ' || c == '\t'; }
637 
638   /// Drops all tokens in front of the expression that are unrelated for
639   /// the completion of the cmd line. 'unrelated' means here that the token
640   /// is not interested for the lldb completion API result.
641   StringRef dropUnrelatedFrontTokens(StringRef cmd) {
642     if (cmd.empty())
643       return cmd;
644 
645     // If we are at the start of a word, then all tokens are unrelated to
646     // the current completion logic.
647     if (IsTokenSeparator(cmd.back()))
648       return StringRef();
649 
650     // Remove all previous tokens from the string as they are unrelated
651     // to completing the current token.
652     StringRef to_remove = cmd;
653     while (!to_remove.empty() && !IsTokenSeparator(to_remove.back())) {
654       to_remove = to_remove.drop_back();
655     }
656     cmd = cmd.drop_front(to_remove.size());
657 
658     return cmd;
659   }
660 
661   /// Removes the last identifier token from the given cmd line.
662   StringRef removeLastToken(StringRef cmd) {
663     while (!cmd.empty() && IsIdChar(cmd.back())) {
664       cmd = cmd.drop_back();
665     }
666     return cmd;
667   }
668 
669   /// Attemps to merge the given completion from the given position into the
670   /// existing command. Returns the completion string that can be returned to
671   /// the lldb completion API.
672   std::string mergeCompletion(StringRef existing, unsigned pos,
673                               StringRef completion) {
674     StringRef existing_command = existing.substr(0, pos);
675     // We rewrite the last token with the completion, so let's drop that
676     // token from the command.
677     existing_command = removeLastToken(existing_command);
678     // We also should remove all previous tokens from the command as they
679     // would otherwise be added to the completion that already has the
680     // completion.
681     existing_command = dropUnrelatedFrontTokens(existing_command);
682     return existing_command.str() + completion.str();
683   }
684 
685 public:
686   /// Constructs a CodeComplete consumer that can be attached to a Sema.
687   /// \param[out] matches
688   ///    The list of matches that the lldb completion API expects as a result.
689   ///    This may already contain matches, so it's only allowed to append
690   ///    to this variable.
691   /// \param[out] expr
692   ///    The whole expression string that we are currently parsing. This
693   ///    string needs to be equal to the input the user typed, and NOT the
694   ///    final code that Clang is parsing.
695   /// \param[out] position
696   ///    The character position of the user cursor in the `expr` parameter.
697   ///
698   CodeComplete(CompletionRequest &request, clang::LangOptions ops,
699                std::string expr, unsigned position)
700       : CodeCompleteConsumer(CodeCompleteOptions()),
701         m_info(std::make_shared<GlobalCodeCompletionAllocator>()), m_expr(expr),
702         m_position(position), m_request(request), m_desc_policy(ops) {
703 
704     // Ensure that the printing policy is producing a description that is as
705     // short as possible.
706     m_desc_policy.SuppressScope = true;
707     m_desc_policy.SuppressTagKeyword = true;
708     m_desc_policy.FullyQualifiedName = false;
709     m_desc_policy.TerseOutput = true;
710     m_desc_policy.IncludeNewlines = false;
711     m_desc_policy.UseVoidForZeroParams = false;
712     m_desc_policy.Bool = true;
713   }
714 
715   /// Deregisters and destroys this code-completion consumer.
716   ~CodeComplete() override {}
717 
718   /// \name Code-completion filtering
719   /// Check if the result should be filtered out.
720   bool isResultFilteredOut(StringRef Filter,
721                            CodeCompletionResult Result) override {
722     // This code is mostly copied from CodeCompleteConsumer.
723     switch (Result.Kind) {
724     case CodeCompletionResult::RK_Declaration:
725       return !(
726           Result.Declaration->getIdentifier() &&
727           Result.Declaration->getIdentifier()->getName().startswith(Filter));
728     case CodeCompletionResult::RK_Keyword:
729       return !StringRef(Result.Keyword).startswith(Filter);
730     case CodeCompletionResult::RK_Macro:
731       return !Result.Macro->getName().startswith(Filter);
732     case CodeCompletionResult::RK_Pattern:
733       return !StringRef(Result.Pattern->getAsString()).startswith(Filter);
734     }
735     // If we trigger this assert or the above switch yields a warning, then
736     // CodeCompletionResult has been enhanced with more kinds of completion
737     // results. Expand the switch above in this case.
738     assert(false && "Unknown completion result type?");
739     // If we reach this, then we should just ignore whatever kind of unknown
740     // result we got back. We probably can't turn it into any kind of useful
741     // completion suggestion with the existing code.
742     return true;
743   }
744 
745   /// \name Code-completion callbacks
746   /// Process the finalized code-completion results.
747   void ProcessCodeCompleteResults(Sema &SemaRef, CodeCompletionContext Context,
748                                   CodeCompletionResult *Results,
749                                   unsigned NumResults) override {
750 
751     // The Sema put the incomplete token we try to complete in here during
752     // lexing, so we need to retrieve it here to know what we are completing.
753     StringRef Filter = SemaRef.getPreprocessor().getCodeCompletionFilter();
754 
755     // Iterate over all the results. Filter out results we don't want and
756     // process the rest.
757     for (unsigned I = 0; I != NumResults; ++I) {
758       // Filter the results with the information from the Sema.
759       if (!Filter.empty() && isResultFilteredOut(Filter, Results[I]))
760         continue;
761 
762       CodeCompletionResult &R = Results[I];
763       std::string ToInsert;
764       std::string Description;
765       // Handle the different completion kinds that come from the Sema.
766       switch (R.Kind) {
767       case CodeCompletionResult::RK_Declaration: {
768         const NamedDecl *D = R.Declaration;
769         ToInsert = R.Declaration->getNameAsString();
770         // If we have a function decl that has no arguments we want to
771         // complete the empty parantheses for the user. If the function has
772         // arguments, we at least complete the opening bracket.
773         if (const FunctionDecl *F = dyn_cast<FunctionDecl>(D)) {
774           if (F->getNumParams() == 0)
775             ToInsert += "()";
776           else
777             ToInsert += "(";
778           raw_string_ostream OS(Description);
779           F->print(OS, m_desc_policy, false);
780           OS.flush();
781         } else if (const VarDecl *V = dyn_cast<VarDecl>(D)) {
782           Description = V->getType().getAsString(m_desc_policy);
783         } else if (const FieldDecl *F = dyn_cast<FieldDecl>(D)) {
784           Description = F->getType().getAsString(m_desc_policy);
785         } else if (const NamespaceDecl *N = dyn_cast<NamespaceDecl>(D)) {
786           // If we try to complete a namespace, then we can directly append
787           // the '::'.
788           if (!N->isAnonymousNamespace())
789             ToInsert += "::";
790         }
791         break;
792       }
793       case CodeCompletionResult::RK_Keyword:
794         ToInsert = R.Keyword;
795         break;
796       case CodeCompletionResult::RK_Macro:
797         ToInsert = R.Macro->getName().str();
798         break;
799       case CodeCompletionResult::RK_Pattern:
800         ToInsert = R.Pattern->getTypedText();
801         break;
802       }
803       // At this point all information is in the ToInsert string.
804 
805       // We also filter some internal lldb identifiers here. The user
806       // shouldn't see these.
807       if (StringRef(ToInsert).startswith("$__lldb_"))
808         continue;
809       if (!ToInsert.empty()) {
810         // Merge the suggested Token into the existing command line to comply
811         // with the kind of result the lldb API expects.
812         std::string CompletionSuggestion =
813             mergeCompletion(m_expr, m_position, ToInsert);
814         m_request.AddCompletion(CompletionSuggestion, Description);
815       }
816     }
817   }
818 
819   /// \param S the semantic-analyzer object for which code-completion is being
820   /// done.
821   ///
822   /// \param CurrentArg the index of the current argument.
823   ///
824   /// \param Candidates an array of overload candidates.
825   ///
826   /// \param NumCandidates the number of overload candidates
827   void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
828                                  OverloadCandidate *Candidates,
829                                  unsigned NumCandidates,
830                                  SourceLocation OpenParLoc) override {
831     // At the moment we don't filter out any overloaded candidates.
832   }
833 
834   CodeCompletionAllocator &getAllocator() override {
835     return m_info.getAllocator();
836   }
837 
838   CodeCompletionTUInfo &getCodeCompletionTUInfo() override { return m_info; }
839 };
840 } // namespace
841 
842 bool ClangExpressionParser::Complete(CompletionRequest &request, unsigned line,
843                                      unsigned pos, unsigned typed_pos) {
844   DiagnosticManager mgr;
845   // We need the raw user expression here because that's what the CodeComplete
846   // class uses to provide completion suggestions.
847   // However, the `Text` method only gives us the transformed expression here.
848   // To actually get the raw user input here, we have to cast our expression to
849   // the LLVMUserExpression which exposes the right API. This should never fail
850   // as we always have a ClangUserExpression whenever we call this.
851   ClangUserExpression *llvm_expr = cast<ClangUserExpression>(&m_expr);
852   CodeComplete CC(request, m_compiler->getLangOpts(), llvm_expr->GetUserText(),
853                   typed_pos);
854   // We don't need a code generator for parsing.
855   m_code_generator.reset();
856   // Start parsing the expression with our custom code completion consumer.
857   ParseInternal(mgr, &CC, line, pos);
858   return true;
859 }
860 
861 unsigned ClangExpressionParser::Parse(DiagnosticManager &diagnostic_manager) {
862   return ParseInternal(diagnostic_manager);
863 }
864 
865 unsigned
866 ClangExpressionParser::ParseInternal(DiagnosticManager &diagnostic_manager,
867                                      CodeCompleteConsumer *completion_consumer,
868                                      unsigned completion_line,
869                                      unsigned completion_column) {
870   ClangDiagnosticManagerAdapter *adapter =
871       static_cast<ClangDiagnosticManagerAdapter *>(
872           m_compiler->getDiagnostics().getClient());
873   auto diag_buf = adapter->GetPassthrough();
874 
875   adapter->ResetManager(&diagnostic_manager);
876 
877   const char *expr_text = m_expr.Text();
878 
879   clang::SourceManager &source_mgr = m_compiler->getSourceManager();
880   bool created_main_file = false;
881 
882   // Clang wants to do completion on a real file known by Clang's file manager,
883   // so we have to create one to make this work.
884   // TODO: We probably could also simulate to Clang's file manager that there
885   // is a real file that contains our code.
886   bool should_create_file = completion_consumer != nullptr;
887 
888   // We also want a real file on disk if we generate full debug info.
889   should_create_file |= m_compiler->getCodeGenOpts().getDebugInfo() ==
890                         codegenoptions::FullDebugInfo;
891 
892   if (should_create_file) {
893     int temp_fd = -1;
894     llvm::SmallString<128> result_path;
895     if (FileSpec tmpdir_file_spec = HostInfo::GetProcessTempDir()) {
896       tmpdir_file_spec.AppendPathComponent("lldb-%%%%%%.expr");
897       std::string temp_source_path = tmpdir_file_spec.GetPath();
898       llvm::sys::fs::createUniqueFile(temp_source_path, temp_fd, result_path);
899     } else {
900       llvm::sys::fs::createTemporaryFile("lldb", "expr", temp_fd, result_path);
901     }
902 
903     if (temp_fd != -1) {
904       lldb_private::File file(temp_fd, true);
905       const size_t expr_text_len = strlen(expr_text);
906       size_t bytes_written = expr_text_len;
907       if (file.Write(expr_text, bytes_written).Success()) {
908         if (bytes_written == expr_text_len) {
909           file.Close();
910           if (auto fileEntry =
911                   m_compiler->getFileManager().getFile(result_path)) {
912             source_mgr.setMainFileID(source_mgr.createFileID(
913                 *fileEntry,
914                 SourceLocation(), SrcMgr::C_User));
915             created_main_file = true;
916           }
917         }
918       }
919     }
920   }
921 
922   if (!created_main_file) {
923     std::unique_ptr<MemoryBuffer> memory_buffer =
924         MemoryBuffer::getMemBufferCopy(expr_text, m_filename);
925     source_mgr.setMainFileID(source_mgr.createFileID(std::move(memory_buffer)));
926   }
927 
928   diag_buf->BeginSourceFile(m_compiler->getLangOpts(),
929                             &m_compiler->getPreprocessor());
930 
931   ClangExpressionHelper *type_system_helper =
932       dyn_cast<ClangExpressionHelper>(m_expr.GetTypeSystemHelper());
933 
934   // If we want to parse for code completion, we need to attach our code
935   // completion consumer to the Sema and specify a completion position.
936   // While parsing the Sema will call this consumer with the provided
937   // completion suggestions.
938   if (completion_consumer) {
939     auto main_file = source_mgr.getFileEntryForID(source_mgr.getMainFileID());
940     auto &PP = m_compiler->getPreprocessor();
941     // Lines and columns start at 1 in Clang, but code completion positions are
942     // indexed from 0, so we need to add 1 to the line and column here.
943     ++completion_line;
944     ++completion_column;
945     PP.SetCodeCompletionPoint(main_file, completion_line, completion_column);
946   }
947 
948   ASTConsumer *ast_transformer =
949       type_system_helper->ASTTransformer(m_code_generator.get());
950 
951   std::unique_ptr<clang::ASTConsumer> Consumer;
952   if (ast_transformer) {
953     Consumer.reset(new ASTConsumerForwarder(ast_transformer));
954   } else if (m_code_generator) {
955     Consumer.reset(new ASTConsumerForwarder(m_code_generator.get()));
956   } else {
957     Consumer.reset(new ASTConsumer());
958   }
959 
960   clang::ASTContext &ast_context = m_compiler->getASTContext();
961 
962   m_compiler->setSema(new Sema(m_compiler->getPreprocessor(), ast_context,
963                                *Consumer, TU_Complete, completion_consumer));
964   m_compiler->setASTConsumer(std::move(Consumer));
965 
966   if (ast_context.getLangOpts().Modules) {
967     m_compiler->createModuleManager();
968     m_ast_context->setSema(&m_compiler->getSema());
969   }
970 
971   ClangExpressionDeclMap *decl_map = type_system_helper->DeclMap();
972   if (decl_map) {
973     decl_map->InstallCodeGenerator(&m_compiler->getASTConsumer());
974 
975     clang::ExternalASTSource *ast_source = decl_map->CreateProxy();
976 
977     if (ast_context.getExternalSource()) {
978       auto module_wrapper =
979           new ExternalASTSourceWrapper(ast_context.getExternalSource());
980 
981       auto ast_source_wrapper = new ExternalASTSourceWrapper(ast_source);
982 
983       auto multiplexer =
984           new SemaSourceWithPriorities(*module_wrapper, *ast_source_wrapper);
985       IntrusiveRefCntPtr<ExternalASTSource> Source(multiplexer);
986       ast_context.setExternalSource(Source);
987     } else {
988       ast_context.setExternalSource(ast_source);
989     }
990     decl_map->InstallASTContext(ast_context, m_compiler->getFileManager());
991   }
992 
993   // Check that the ASTReader is properly attached to ASTContext and Sema.
994   if (ast_context.getLangOpts().Modules) {
995     assert(m_compiler->getASTContext().getExternalSource() &&
996            "ASTContext doesn't know about the ASTReader?");
997     assert(m_compiler->getSema().getExternalSource() &&
998            "Sema doesn't know about the ASTReader?");
999   }
1000 
1001   {
1002     llvm::CrashRecoveryContextCleanupRegistrar<Sema> CleanupSema(
1003         &m_compiler->getSema());
1004     ParseAST(m_compiler->getSema(), false, false);
1005   }
1006 
1007   // Make sure we have no pointer to the Sema we are about to destroy.
1008   if (ast_context.getLangOpts().Modules)
1009     m_ast_context->setSema(nullptr);
1010   // Destroy the Sema. This is necessary because we want to emulate the
1011   // original behavior of ParseAST (which also destroys the Sema after parsing).
1012   m_compiler->setSema(nullptr);
1013 
1014   diag_buf->EndSourceFile();
1015 
1016   unsigned num_errors = diag_buf->getNumErrors();
1017 
1018   if (m_pp_callbacks && m_pp_callbacks->hasErrors()) {
1019     num_errors++;
1020     diagnostic_manager.PutString(eDiagnosticSeverityError,
1021                                  "while importing modules:");
1022     diagnostic_manager.AppendMessageToDiagnostic(
1023         m_pp_callbacks->getErrorString());
1024   }
1025 
1026   if (!num_errors) {
1027     if (type_system_helper->DeclMap() &&
1028         !type_system_helper->DeclMap()->ResolveUnknownTypes()) {
1029       diagnostic_manager.Printf(eDiagnosticSeverityError,
1030                                 "Couldn't infer the type of a variable");
1031       num_errors++;
1032     }
1033   }
1034 
1035   if (!num_errors) {
1036     type_system_helper->CommitPersistentDecls();
1037   }
1038 
1039   adapter->ResetManager();
1040 
1041   return num_errors;
1042 }
1043 
1044 std::string
1045 ClangExpressionParser::GetClangTargetABI(const ArchSpec &target_arch) {
1046   std::string abi;
1047 
1048   if (target_arch.IsMIPS()) {
1049     switch (target_arch.GetFlags() & ArchSpec::eMIPSABI_mask) {
1050     case ArchSpec::eMIPSABI_N64:
1051       abi = "n64";
1052       break;
1053     case ArchSpec::eMIPSABI_N32:
1054       abi = "n32";
1055       break;
1056     case ArchSpec::eMIPSABI_O32:
1057       abi = "o32";
1058       break;
1059     default:
1060       break;
1061     }
1062   }
1063   return abi;
1064 }
1065 
1066 bool ClangExpressionParser::RewriteExpression(
1067     DiagnosticManager &diagnostic_manager) {
1068   clang::SourceManager &source_manager = m_compiler->getSourceManager();
1069   clang::edit::EditedSource editor(source_manager, m_compiler->getLangOpts(),
1070                                    nullptr);
1071   clang::edit::Commit commit(editor);
1072   clang::Rewriter rewriter(source_manager, m_compiler->getLangOpts());
1073 
1074   class RewritesReceiver : public edit::EditsReceiver {
1075     Rewriter &rewrite;
1076 
1077   public:
1078     RewritesReceiver(Rewriter &in_rewrite) : rewrite(in_rewrite) {}
1079 
1080     void insert(SourceLocation loc, StringRef text) override {
1081       rewrite.InsertText(loc, text);
1082     }
1083     void replace(CharSourceRange range, StringRef text) override {
1084       rewrite.ReplaceText(range.getBegin(), rewrite.getRangeSize(range), text);
1085     }
1086   };
1087 
1088   RewritesReceiver rewrites_receiver(rewriter);
1089 
1090   const DiagnosticList &diagnostics = diagnostic_manager.Diagnostics();
1091   size_t num_diags = diagnostics.size();
1092   if (num_diags == 0)
1093     return false;
1094 
1095   for (const Diagnostic *diag : diagnostic_manager.Diagnostics()) {
1096     const ClangDiagnostic *diagnostic = llvm::dyn_cast<ClangDiagnostic>(diag);
1097     if (diagnostic && diagnostic->HasFixIts()) {
1098       for (const FixItHint &fixit : diagnostic->FixIts()) {
1099         // This is cobbed from clang::Rewrite::FixItRewriter.
1100         if (fixit.CodeToInsert.empty()) {
1101           if (fixit.InsertFromRange.isValid()) {
1102             commit.insertFromRange(fixit.RemoveRange.getBegin(),
1103                                    fixit.InsertFromRange, /*afterToken=*/false,
1104                                    fixit.BeforePreviousInsertions);
1105           } else
1106             commit.remove(fixit.RemoveRange);
1107         } else {
1108           if (fixit.RemoveRange.isTokenRange() ||
1109               fixit.RemoveRange.getBegin() != fixit.RemoveRange.getEnd())
1110             commit.replace(fixit.RemoveRange, fixit.CodeToInsert);
1111           else
1112             commit.insert(fixit.RemoveRange.getBegin(), fixit.CodeToInsert,
1113                           /*afterToken=*/false, fixit.BeforePreviousInsertions);
1114         }
1115       }
1116     }
1117   }
1118 
1119   // FIXME - do we want to try to propagate specific errors here?
1120   if (!commit.isCommitable())
1121     return false;
1122   else if (!editor.commit(commit))
1123     return false;
1124 
1125   // Now play all the edits, and stash the result in the diagnostic manager.
1126   editor.applyRewrites(rewrites_receiver);
1127   RewriteBuffer &main_file_buffer =
1128       rewriter.getEditBuffer(source_manager.getMainFileID());
1129 
1130   std::string fixed_expression;
1131   llvm::raw_string_ostream out_stream(fixed_expression);
1132 
1133   main_file_buffer.write(out_stream);
1134   out_stream.flush();
1135   diagnostic_manager.SetFixedExpression(fixed_expression);
1136 
1137   return true;
1138 }
1139 
1140 static bool FindFunctionInModule(ConstString &mangled_name,
1141                                  llvm::Module *module, const char *orig_name) {
1142   for (const auto &func : module->getFunctionList()) {
1143     const StringRef &name = func.getName();
1144     if (name.find(orig_name) != StringRef::npos) {
1145       mangled_name.SetString(name);
1146       return true;
1147     }
1148   }
1149 
1150   return false;
1151 }
1152 
1153 lldb_private::Status ClangExpressionParser::PrepareForExecution(
1154     lldb::addr_t &func_addr, lldb::addr_t &func_end,
1155     lldb::IRExecutionUnitSP &execution_unit_sp, ExecutionContext &exe_ctx,
1156     bool &can_interpret, ExecutionPolicy execution_policy) {
1157   func_addr = LLDB_INVALID_ADDRESS;
1158   func_end = LLDB_INVALID_ADDRESS;
1159   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
1160 
1161   lldb_private::Status err;
1162 
1163   std::unique_ptr<llvm::Module> llvm_module_up(
1164       m_code_generator->ReleaseModule());
1165 
1166   if (!llvm_module_up) {
1167     err.SetErrorToGenericError();
1168     err.SetErrorString("IR doesn't contain a module");
1169     return err;
1170   }
1171 
1172   ConstString function_name;
1173 
1174   if (execution_policy != eExecutionPolicyTopLevel) {
1175     // Find the actual name of the function (it's often mangled somehow)
1176 
1177     if (!FindFunctionInModule(function_name, llvm_module_up.get(),
1178                               m_expr.FunctionName())) {
1179       err.SetErrorToGenericError();
1180       err.SetErrorStringWithFormat("Couldn't find %s() in the module",
1181                                    m_expr.FunctionName());
1182       return err;
1183     } else {
1184       LLDB_LOGF(log, "Found function %s for %s", function_name.AsCString(),
1185                 m_expr.FunctionName());
1186     }
1187   }
1188 
1189   SymbolContext sc;
1190 
1191   if (lldb::StackFrameSP frame_sp = exe_ctx.GetFrameSP()) {
1192     sc = frame_sp->GetSymbolContext(lldb::eSymbolContextEverything);
1193   } else if (lldb::TargetSP target_sp = exe_ctx.GetTargetSP()) {
1194     sc.target_sp = target_sp;
1195   }
1196 
1197   LLVMUserExpression::IRPasses custom_passes;
1198   {
1199     auto lang = m_expr.Language();
1200     LLDB_LOGF(log, "%s - Current expression language is %s\n", __FUNCTION__,
1201               Language::GetNameForLanguageType(lang));
1202     lldb::ProcessSP process_sp = exe_ctx.GetProcessSP();
1203     if (process_sp && lang != lldb::eLanguageTypeUnknown) {
1204       auto runtime = process_sp->GetLanguageRuntime(lang);
1205       if (runtime)
1206         runtime->GetIRPasses(custom_passes);
1207     }
1208   }
1209 
1210   if (custom_passes.EarlyPasses) {
1211     LLDB_LOGF(log,
1212               "%s - Running Early IR Passes from LanguageRuntime on "
1213               "expression module '%s'",
1214               __FUNCTION__, m_expr.FunctionName());
1215 
1216     custom_passes.EarlyPasses->run(*llvm_module_up);
1217   }
1218 
1219   execution_unit_sp = std::make_shared<IRExecutionUnit>(
1220       m_llvm_context, // handed off here
1221       llvm_module_up, // handed off here
1222       function_name, exe_ctx.GetTargetSP(), sc,
1223       m_compiler->getTargetOpts().Features);
1224 
1225   ClangExpressionHelper *type_system_helper =
1226       dyn_cast<ClangExpressionHelper>(m_expr.GetTypeSystemHelper());
1227   ClangExpressionDeclMap *decl_map =
1228       type_system_helper->DeclMap(); // result can be NULL
1229 
1230   if (decl_map) {
1231     Stream *error_stream = nullptr;
1232     Target *target = exe_ctx.GetTargetPtr();
1233     error_stream = target->GetDebugger().GetErrorFile().get();
1234 
1235     IRForTarget ir_for_target(decl_map, m_expr.NeedsVariableResolution(),
1236                               *execution_unit_sp, *error_stream,
1237                               function_name.AsCString());
1238 
1239     bool ir_can_run =
1240         ir_for_target.runOnModule(*execution_unit_sp->GetModule());
1241 
1242     if (!ir_can_run) {
1243       err.SetErrorString(
1244           "The expression could not be prepared to run in the target");
1245       return err;
1246     }
1247 
1248     Process *process = exe_ctx.GetProcessPtr();
1249 
1250     if (execution_policy != eExecutionPolicyAlways &&
1251         execution_policy != eExecutionPolicyTopLevel) {
1252       lldb_private::Status interpret_error;
1253 
1254       bool interpret_function_calls =
1255           !process ? false : process->CanInterpretFunctionCalls();
1256       can_interpret = IRInterpreter::CanInterpret(
1257           *execution_unit_sp->GetModule(), *execution_unit_sp->GetFunction(),
1258           interpret_error, interpret_function_calls);
1259 
1260       if (!can_interpret && execution_policy == eExecutionPolicyNever) {
1261         err.SetErrorStringWithFormat("Can't run the expression locally: %s",
1262                                      interpret_error.AsCString());
1263         return err;
1264       }
1265     }
1266 
1267     if (!process && execution_policy == eExecutionPolicyAlways) {
1268       err.SetErrorString("Expression needed to run in the target, but the "
1269                          "target can't be run");
1270       return err;
1271     }
1272 
1273     if (!process && execution_policy == eExecutionPolicyTopLevel) {
1274       err.SetErrorString("Top-level code needs to be inserted into a runnable "
1275                          "target, but the target can't be run");
1276       return err;
1277     }
1278 
1279     if (execution_policy == eExecutionPolicyAlways ||
1280         (execution_policy != eExecutionPolicyTopLevel && !can_interpret)) {
1281       if (m_expr.NeedsValidation() && process) {
1282         if (!process->GetDynamicCheckers()) {
1283           ClangDynamicCheckerFunctions *dynamic_checkers =
1284               new ClangDynamicCheckerFunctions();
1285 
1286           DiagnosticManager install_diagnostics;
1287 
1288           if (!dynamic_checkers->Install(install_diagnostics, exe_ctx)) {
1289             if (install_diagnostics.Diagnostics().size())
1290               err.SetErrorString(install_diagnostics.GetString().c_str());
1291             else
1292               err.SetErrorString("couldn't install checkers, unknown error");
1293 
1294             return err;
1295           }
1296 
1297           process->SetDynamicCheckers(dynamic_checkers);
1298 
1299           LLDB_LOGF(log, "== [ClangExpressionParser::PrepareForExecution] "
1300                          "Finished installing dynamic checkers ==");
1301         }
1302 
1303         if (auto *checker_funcs = llvm::dyn_cast<ClangDynamicCheckerFunctions>(
1304                 process->GetDynamicCheckers())) {
1305           IRDynamicChecks ir_dynamic_checks(*checker_funcs,
1306                                             function_name.AsCString());
1307 
1308           llvm::Module *module = execution_unit_sp->GetModule();
1309           if (!module || !ir_dynamic_checks.runOnModule(*module)) {
1310             err.SetErrorToGenericError();
1311             err.SetErrorString("Couldn't add dynamic checks to the expression");
1312             return err;
1313           }
1314 
1315           if (custom_passes.LatePasses) {
1316             LLDB_LOGF(log,
1317                       "%s - Running Late IR Passes from LanguageRuntime on "
1318                       "expression module '%s'",
1319                       __FUNCTION__, m_expr.FunctionName());
1320 
1321             custom_passes.LatePasses->run(*module);
1322           }
1323         }
1324       }
1325     }
1326 
1327     if (execution_policy == eExecutionPolicyAlways ||
1328         execution_policy == eExecutionPolicyTopLevel || !can_interpret) {
1329       execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);
1330     }
1331   } else {
1332     execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);
1333   }
1334 
1335   return err;
1336 }
1337 
1338 lldb_private::Status ClangExpressionParser::RunStaticInitializers(
1339     lldb::IRExecutionUnitSP &execution_unit_sp, ExecutionContext &exe_ctx) {
1340   lldb_private::Status err;
1341 
1342   lldbassert(execution_unit_sp.get());
1343   lldbassert(exe_ctx.HasThreadScope());
1344 
1345   if (!execution_unit_sp.get()) {
1346     err.SetErrorString(
1347         "can't run static initializers for a NULL execution unit");
1348     return err;
1349   }
1350 
1351   if (!exe_ctx.HasThreadScope()) {
1352     err.SetErrorString("can't run static initializers without a thread");
1353     return err;
1354   }
1355 
1356   std::vector<lldb::addr_t> static_initializers;
1357 
1358   execution_unit_sp->GetStaticInitializers(static_initializers);
1359 
1360   for (lldb::addr_t static_initializer : static_initializers) {
1361     EvaluateExpressionOptions options;
1362 
1363     lldb::ThreadPlanSP call_static_initializer(new ThreadPlanCallFunction(
1364         exe_ctx.GetThreadRef(), Address(static_initializer), CompilerType(),
1365         llvm::ArrayRef<lldb::addr_t>(), options));
1366 
1367     DiagnosticManager execution_errors;
1368     lldb::ExpressionResults results =
1369         exe_ctx.GetThreadRef().GetProcess()->RunThreadPlan(
1370             exe_ctx, call_static_initializer, options, execution_errors);
1371 
1372     if (results != lldb::eExpressionCompleted) {
1373       err.SetErrorStringWithFormat("couldn't run static initializer: %s",
1374                                    execution_errors.GetString().c_str());
1375       return err;
1376     }
1377   }
1378 
1379   return err;
1380 }
1381