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1 //===-- ClangExpressionParser.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 "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/Builtins.h"
14 #include "clang/Basic/DiagnosticIDs.h"
15 #include "clang/Basic/SourceLocation.h"
16 #include "clang/Basic/TargetInfo.h"
17 #include "clang/Basic/Version.h"
18 #include "clang/CodeGen/CodeGenAction.h"
19 #include "clang/CodeGen/ModuleBuilder.h"
20 #include "clang/Edit/Commit.h"
21 #include "clang/Edit/EditedSource.h"
22 #include "clang/Edit/EditsReceiver.h"
23 #include "clang/Frontend/CompilerInstance.h"
24 #include "clang/Frontend/CompilerInvocation.h"
25 #include "clang/Frontend/FrontendActions.h"
26 #include "clang/Frontend/FrontendDiagnostic.h"
27 #include "clang/Frontend/FrontendPluginRegistry.h"
28 #include "clang/Frontend/TextDiagnosticBuffer.h"
29 #include "clang/Frontend/TextDiagnosticPrinter.h"
30 #include "clang/Lex/Preprocessor.h"
31 #include "clang/Parse/ParseAST.h"
32 #include "clang/Rewrite/Core/Rewriter.h"
33 #include "clang/Rewrite/Frontend/FrontendActions.h"
34 #include "clang/Sema/CodeCompleteConsumer.h"
35 #include "clang/Sema/Sema.h"
36 #include "clang/Sema/SemaConsumer.h"
37 
38 #include "llvm/ADT/StringRef.h"
39 #include "llvm/ExecutionEngine/ExecutionEngine.h"
40 #include "llvm/Support/CrashRecoveryContext.h"
41 #include "llvm/Support/Debug.h"
42 #include "llvm/Support/FileSystem.h"
43 #include "llvm/Support/TargetSelect.h"
44 
45 #include "llvm/IR/LLVMContext.h"
46 #include "llvm/IR/Module.h"
47 #include "llvm/Support/DynamicLibrary.h"
48 #include "llvm/Support/ErrorHandling.h"
49 #include "llvm/Support/Host.h"
50 #include "llvm/Support/MemoryBuffer.h"
51 #include "llvm/Support/Signals.h"
52 
53 #include "ClangDiagnostic.h"
54 #include "ClangExpressionParser.h"
55 #include "ClangUserExpression.h"
56 
57 #include "ASTUtils.h"
58 #include "ClangASTSource.h"
59 #include "ClangDiagnostic.h"
60 #include "ClangExpressionDeclMap.h"
61 #include "ClangExpressionHelper.h"
62 #include "ClangExpressionParser.h"
63 #include "ClangHost.h"
64 #include "ClangModulesDeclVendor.h"
65 #include "ClangPersistentVariables.h"
66 #include "IRDynamicChecks.h"
67 #include "IRForTarget.h"
68 #include "ModuleDependencyCollector.h"
69 
70 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
71 #include "lldb/Core/Debugger.h"
72 #include "lldb/Core/Disassembler.h"
73 #include "lldb/Core/Module.h"
74 #include "lldb/Core/StreamFile.h"
75 #include "lldb/Expression/IRExecutionUnit.h"
76 #include "lldb/Expression/IRInterpreter.h"
77 #include "lldb/Host/File.h"
78 #include "lldb/Host/HostInfo.h"
79 #include "lldb/Symbol/SymbolVendor.h"
80 #include "lldb/Target/ExecutionContext.h"
81 #include "lldb/Target/Language.h"
82 #include "lldb/Target/Process.h"
83 #include "lldb/Target/Target.h"
84 #include "lldb/Target/ThreadPlanCallFunction.h"
85 #include "lldb/Utility/DataBufferHeap.h"
86 #include "lldb/Utility/LLDBAssert.h"
87 #include "lldb/Utility/Log.h"
88 #include "lldb/Utility/ReproducerProvider.h"
89 #include "lldb/Utility/Stream.h"
90 #include "lldb/Utility/StreamString.h"
91 #include "lldb/Utility/StringList.h"
92 
93 #include "Plugins/LanguageRuntime/ObjC/ObjCLanguageRuntime.h"
94 #include "Plugins/LanguageRuntime/RenderScript/RenderScriptRuntime/RenderScriptRuntime.h"
95 
96 #include <cctype>
97 #include <memory>
98 
99 using namespace clang;
100 using namespace llvm;
101 using namespace lldb_private;
102 
103 //===----------------------------------------------------------------------===//
104 // Utility Methods for Clang
105 //===----------------------------------------------------------------------===//
106 
107 class ClangExpressionParser::LLDBPreprocessorCallbacks : public PPCallbacks {
108   ClangModulesDeclVendor &m_decl_vendor;
109   ClangPersistentVariables &m_persistent_vars;
110   clang::SourceManager &m_source_mgr;
111   StreamString m_error_stream;
112   bool m_has_errors = false;
113 
114 public:
LLDBPreprocessorCallbacks(ClangModulesDeclVendor & decl_vendor,ClangPersistentVariables & persistent_vars,clang::SourceManager & source_mgr)115   LLDBPreprocessorCallbacks(ClangModulesDeclVendor &decl_vendor,
116                             ClangPersistentVariables &persistent_vars,
117                             clang::SourceManager &source_mgr)
118       : m_decl_vendor(decl_vendor), m_persistent_vars(persistent_vars),
119         m_source_mgr(source_mgr) {}
120 
moduleImport(SourceLocation import_location,clang::ModuleIdPath path,const clang::Module *)121   void moduleImport(SourceLocation import_location, clang::ModuleIdPath path,
122                     const clang::Module * /*null*/) override {
123     // Ignore modules that are imported in the wrapper code as these are not
124     // loaded by the user.
125     llvm::StringRef filename =
126         m_source_mgr.getPresumedLoc(import_location).getFilename();
127     if (filename == ClangExpressionSourceCode::g_prefix_file_name)
128       return;
129 
130     SourceModule module;
131 
132     for (const std::pair<IdentifierInfo *, SourceLocation> &component : path)
133       module.path.push_back(ConstString(component.first->getName()));
134 
135     StreamString error_stream;
136 
137     ClangModulesDeclVendor::ModuleVector exported_modules;
138     if (!m_decl_vendor.AddModule(module, &exported_modules, m_error_stream))
139       m_has_errors = true;
140 
141     for (ClangModulesDeclVendor::ModuleID module : exported_modules)
142       m_persistent_vars.AddHandLoadedClangModule(module);
143   }
144 
hasErrors()145   bool hasErrors() { return m_has_errors; }
146 
getErrorString()147   llvm::StringRef getErrorString() { return m_error_stream.GetString(); }
148 };
149 
AddAllFixIts(ClangDiagnostic * diag,const clang::Diagnostic & Info)150 static void AddAllFixIts(ClangDiagnostic *diag, const clang::Diagnostic &Info) {
151   for (auto &fix_it : Info.getFixItHints()) {
152     if (fix_it.isNull())
153       continue;
154     diag->AddFixitHint(fix_it);
155   }
156 }
157 
158 class ClangDiagnosticManagerAdapter : public clang::DiagnosticConsumer {
159 public:
ClangDiagnosticManagerAdapter(DiagnosticOptions & opts)160   ClangDiagnosticManagerAdapter(DiagnosticOptions &opts) {
161     DiagnosticOptions *options = new DiagnosticOptions(opts);
162     options->ShowPresumedLoc = true;
163     options->ShowLevel = false;
164     m_os = std::make_shared<llvm::raw_string_ostream>(m_output);
165     m_passthrough =
166         std::make_shared<clang::TextDiagnosticPrinter>(*m_os, options);
167   }
168 
ResetManager(DiagnosticManager * manager=nullptr)169   void ResetManager(DiagnosticManager *manager = nullptr) {
170     m_manager = manager;
171   }
172 
173   /// Returns the last ClangDiagnostic message that the DiagnosticManager
174   /// received or a nullptr if the DiagnosticMangager hasn't seen any
175   /// Clang diagnostics yet.
MaybeGetLastClangDiag() const176   ClangDiagnostic *MaybeGetLastClangDiag() const {
177     if (m_manager->Diagnostics().empty())
178       return nullptr;
179     lldb_private::Diagnostic *diag = m_manager->Diagnostics().back().get();
180     ClangDiagnostic *clang_diag = dyn_cast<ClangDiagnostic>(diag);
181     return clang_diag;
182   }
183 
HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,const clang::Diagnostic & Info)184   void HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
185                         const clang::Diagnostic &Info) override {
186     if (!m_manager) {
187       // We have no DiagnosticManager before/after parsing but we still could
188       // receive diagnostics (e.g., by the ASTImporter failing to copy decls
189       // when we move the expression result ot the ScratchASTContext). Let's at
190       // least log these diagnostics until we find a way to properly render
191       // them and display them to the user.
192       Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
193       if (log) {
194         llvm::SmallVector<char, 32> diag_str;
195         Info.FormatDiagnostic(diag_str);
196         diag_str.push_back('\0');
197         const char *plain_diag = diag_str.data();
198         LLDB_LOG(log, "Received diagnostic outside parsing: {0}", plain_diag);
199       }
200       return;
201     }
202 
203     // Update error/warning counters.
204     DiagnosticConsumer::HandleDiagnostic(DiagLevel, Info);
205 
206     // Render diagnostic message to m_output.
207     m_output.clear();
208     m_passthrough->HandleDiagnostic(DiagLevel, Info);
209     m_os->flush();
210 
211     lldb_private::DiagnosticSeverity severity;
212     bool make_new_diagnostic = true;
213 
214     switch (DiagLevel) {
215     case DiagnosticsEngine::Level::Fatal:
216     case DiagnosticsEngine::Level::Error:
217       severity = eDiagnosticSeverityError;
218       break;
219     case DiagnosticsEngine::Level::Warning:
220       severity = eDiagnosticSeverityWarning;
221       break;
222     case DiagnosticsEngine::Level::Remark:
223     case DiagnosticsEngine::Level::Ignored:
224       severity = eDiagnosticSeverityRemark;
225       break;
226     case DiagnosticsEngine::Level::Note:
227       m_manager->AppendMessageToDiagnostic(m_output);
228       make_new_diagnostic = false;
229 
230       // 'note:' diagnostics for errors and warnings can also contain Fix-Its.
231       // We add these Fix-Its to the last error diagnostic to make sure
232       // that we later have all Fix-Its related to an 'error' diagnostic when
233       // we apply them to the user expression.
234       auto *clang_diag = MaybeGetLastClangDiag();
235       // If we don't have a previous diagnostic there is nothing to do.
236       // If the previous diagnostic already has its own Fix-Its, assume that
237       // the 'note:' Fix-It is just an alternative way to solve the issue and
238       // ignore these Fix-Its.
239       if (!clang_diag || clang_diag->HasFixIts())
240         break;
241       // Ignore all Fix-Its that are not associated with an error.
242       if (clang_diag->GetSeverity() != eDiagnosticSeverityError)
243         break;
244       AddAllFixIts(clang_diag, Info);
245       break;
246     }
247     if (make_new_diagnostic) {
248       // ClangDiagnostic messages are expected to have no whitespace/newlines
249       // around them.
250       std::string stripped_output =
251           std::string(llvm::StringRef(m_output).trim());
252 
253       auto new_diagnostic = std::make_unique<ClangDiagnostic>(
254           stripped_output, severity, Info.getID());
255 
256       // Don't store away warning fixits, since the compiler doesn't have
257       // enough context in an expression for the warning to be useful.
258       // FIXME: Should we try to filter out FixIts that apply to our generated
259       // code, and not the user's expression?
260       if (severity == eDiagnosticSeverityError)
261         AddAllFixIts(new_diagnostic.get(), Info);
262 
263       m_manager->AddDiagnostic(std::move(new_diagnostic));
264     }
265   }
266 
BeginSourceFile(const LangOptions & LO,const Preprocessor * PP)267   void BeginSourceFile(const LangOptions &LO, const Preprocessor *PP) override {
268     m_passthrough->BeginSourceFile(LO, PP);
269   }
270 
EndSourceFile()271   void EndSourceFile() override { m_passthrough->EndSourceFile(); }
272 
273 private:
274   DiagnosticManager *m_manager = nullptr;
275   std::shared_ptr<clang::TextDiagnosticPrinter> m_passthrough;
276   /// Output stream of m_passthrough.
277   std::shared_ptr<llvm::raw_string_ostream> m_os;
278   /// Output string filled by m_os.
279   std::string m_output;
280 };
281 
SetupModuleHeaderPaths(CompilerInstance * compiler,std::vector<std::string> include_directories,lldb::TargetSP target_sp)282 static void SetupModuleHeaderPaths(CompilerInstance *compiler,
283                                    std::vector<std::string> include_directories,
284                                    lldb::TargetSP target_sp) {
285   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
286 
287   HeaderSearchOptions &search_opts = compiler->getHeaderSearchOpts();
288 
289   for (const std::string &dir : include_directories) {
290     search_opts.AddPath(dir, frontend::System, false, true);
291     LLDB_LOG(log, "Added user include dir: {0}", dir);
292   }
293 
294   llvm::SmallString<128> module_cache;
295   const auto &props = ModuleList::GetGlobalModuleListProperties();
296   props.GetClangModulesCachePath().GetPath(module_cache);
297   search_opts.ModuleCachePath = std::string(module_cache.str());
298   LLDB_LOG(log, "Using module cache path: {0}", module_cache.c_str());
299 
300   search_opts.ResourceDir = GetClangResourceDir().GetPath();
301 
302   search_opts.ImplicitModuleMaps = true;
303 }
304 
305 /// Iff the given identifier is a C++ keyword, remove it from the
306 /// identifier table (i.e., make the token a normal identifier).
RemoveCppKeyword(IdentifierTable & idents,llvm::StringRef token)307 static void RemoveCppKeyword(IdentifierTable &idents, llvm::StringRef token) {
308   // FIXME: 'using' is used by LLDB for local variables, so we can't remove
309   // this keyword without breaking this functionality.
310   if (token == "using")
311     return;
312   // GCC's '__null' is used by LLDB to define NULL/Nil/nil.
313   if (token == "__null")
314     return;
315 
316   LangOptions cpp_lang_opts;
317   cpp_lang_opts.CPlusPlus = true;
318   cpp_lang_opts.CPlusPlus11 = true;
319   cpp_lang_opts.CPlusPlus20 = true;
320 
321   clang::IdentifierInfo &ii = idents.get(token);
322   // The identifier has to be a C++-exclusive keyword. if not, then there is
323   // nothing to do.
324   if (!ii.isCPlusPlusKeyword(cpp_lang_opts))
325     return;
326   // If the token is already an identifier, then there is nothing to do.
327   if (ii.getTokenID() == clang::tok::identifier)
328     return;
329   // Otherwise the token is a C++ keyword, so turn it back into a normal
330   // identifier.
331   ii.revertTokenIDToIdentifier();
332 }
333 
334 /// Remove all C++ keywords from the given identifier table.
RemoveAllCppKeywords(IdentifierTable & idents)335 static void RemoveAllCppKeywords(IdentifierTable &idents) {
336 #define KEYWORD(NAME, FLAGS) RemoveCppKeyword(idents, llvm::StringRef(#NAME));
337 #include "clang/Basic/TokenKinds.def"
338 }
339 
340 //===----------------------------------------------------------------------===//
341 // Implementation of ClangExpressionParser
342 //===----------------------------------------------------------------------===//
343 
ClangExpressionParser(ExecutionContextScope * exe_scope,Expression & expr,bool generate_debug_info,std::vector<std::string> include_directories,std::string filename)344 ClangExpressionParser::ClangExpressionParser(
345     ExecutionContextScope *exe_scope, Expression &expr,
346     bool generate_debug_info, std::vector<std::string> include_directories,
347     std::string filename)
348     : ExpressionParser(exe_scope, expr, generate_debug_info), m_compiler(),
349       m_pp_callbacks(nullptr),
350       m_include_directories(std::move(include_directories)),
351       m_filename(std::move(filename)) {
352   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
353 
354   // We can't compile expressions without a target.  So if the exe_scope is
355   // null or doesn't have a target, then we just need to get out of here.  I'll
356   // lldbassert and not make any of the compiler objects since
357   // I can't return errors directly from the constructor.  Further calls will
358   // check if the compiler was made and
359   // bag out if it wasn't.
360 
361   if (!exe_scope) {
362     lldbassert(exe_scope &&
363                "Can't make an expression parser with a null scope.");
364     return;
365   }
366 
367   lldb::TargetSP target_sp;
368   target_sp = exe_scope->CalculateTarget();
369   if (!target_sp) {
370     lldbassert(target_sp.get() &&
371                "Can't make an expression parser with a null target.");
372     return;
373   }
374 
375   // 1. Create a new compiler instance.
376   m_compiler = std::make_unique<CompilerInstance>();
377 
378   // When capturing a reproducer, hook up the file collector with clang to
379   // collector modules and headers.
380   if (repro::Generator *g = repro::Reproducer::Instance().GetGenerator()) {
381     repro::FileProvider &fp = g->GetOrCreate<repro::FileProvider>();
382     m_compiler->setModuleDepCollector(
383         std::make_shared<ModuleDependencyCollectorAdaptor>(
384             fp.GetFileCollector()));
385     DependencyOutputOptions &opts = m_compiler->getDependencyOutputOpts();
386     opts.IncludeSystemHeaders = true;
387     opts.IncludeModuleFiles = true;
388   }
389 
390   // Make sure clang uses the same VFS as LLDB.
391   m_compiler->createFileManager(FileSystem::Instance().GetVirtualFileSystem());
392 
393   lldb::LanguageType frame_lang =
394       expr.Language(); // defaults to lldb::eLanguageTypeUnknown
395   bool overridden_target_opts = false;
396   lldb_private::LanguageRuntime *lang_rt = nullptr;
397 
398   std::string abi;
399   ArchSpec target_arch;
400   target_arch = target_sp->GetArchitecture();
401 
402   const auto target_machine = target_arch.GetMachine();
403 
404   // If the expression is being evaluated in the context of an existing stack
405   // frame, we introspect to see if the language runtime is available.
406 
407   lldb::StackFrameSP frame_sp = exe_scope->CalculateStackFrame();
408   lldb::ProcessSP process_sp = exe_scope->CalculateProcess();
409 
410   // Make sure the user hasn't provided a preferred execution language with
411   // `expression --language X -- ...`
412   if (frame_sp && frame_lang == lldb::eLanguageTypeUnknown)
413     frame_lang = frame_sp->GetLanguage();
414 
415   if (process_sp && frame_lang != lldb::eLanguageTypeUnknown) {
416     lang_rt = process_sp->GetLanguageRuntime(frame_lang);
417     LLDB_LOGF(log, "Frame has language of type %s",
418               Language::GetNameForLanguageType(frame_lang));
419   }
420 
421   // 2. Configure the compiler with a set of default options that are
422   // appropriate for most situations.
423   if (target_arch.IsValid()) {
424     std::string triple = target_arch.GetTriple().str();
425     m_compiler->getTargetOpts().Triple = triple;
426     LLDB_LOGF(log, "Using %s as the target triple",
427               m_compiler->getTargetOpts().Triple.c_str());
428   } else {
429     // If we get here we don't have a valid target and just have to guess.
430     // Sometimes this will be ok to just use the host target triple (when we
431     // evaluate say "2+3", but other expressions like breakpoint conditions and
432     // other things that _are_ target specific really shouldn't just be using
433     // the host triple. In such a case the language runtime should expose an
434     // overridden options set (3), below.
435     m_compiler->getTargetOpts().Triple = llvm::sys::getDefaultTargetTriple();
436     LLDB_LOGF(log, "Using default target triple of %s",
437               m_compiler->getTargetOpts().Triple.c_str());
438   }
439   // Now add some special fixes for known architectures: Any arm32 iOS
440   // environment, but not on arm64
441   if (m_compiler->getTargetOpts().Triple.find("arm64") == std::string::npos &&
442       m_compiler->getTargetOpts().Triple.find("arm") != std::string::npos &&
443       m_compiler->getTargetOpts().Triple.find("ios") != std::string::npos) {
444     m_compiler->getTargetOpts().ABI = "apcs-gnu";
445   }
446   // Supported subsets of x86
447   if (target_machine == llvm::Triple::x86 ||
448       target_machine == llvm::Triple::x86_64) {
449     m_compiler->getTargetOpts().Features.push_back("+sse");
450     m_compiler->getTargetOpts().Features.push_back("+sse2");
451   }
452 
453   // Set the target CPU to generate code for. This will be empty for any CPU
454   // that doesn't really need to make a special
455   // CPU string.
456   m_compiler->getTargetOpts().CPU = target_arch.GetClangTargetCPU();
457 
458   // Set the target ABI
459   abi = GetClangTargetABI(target_arch);
460   if (!abi.empty())
461     m_compiler->getTargetOpts().ABI = abi;
462 
463   // 3. Now allow the runtime to provide custom configuration options for the
464   // target. In this case, a specialized language runtime is available and we
465   // can query it for extra options. For 99% of use cases, this will not be
466   // needed and should be provided when basic platform detection is not enough.
467   // FIXME: Generalize this. Only RenderScriptRuntime currently supports this
468   // currently. Hardcoding this isn't ideal but it's better than LanguageRuntime
469   // having knowledge of clang::TargetOpts.
470   if (auto *renderscript_rt =
471           llvm::dyn_cast_or_null<RenderScriptRuntime>(lang_rt))
472     overridden_target_opts =
473         renderscript_rt->GetOverrideExprOptions(m_compiler->getTargetOpts());
474 
475   if (overridden_target_opts)
476     if (log && log->GetVerbose()) {
477       LLDB_LOGV(
478           log, "Using overridden target options for the expression evaluation");
479 
480       auto opts = m_compiler->getTargetOpts();
481       LLDB_LOGV(log, "Triple: '{0}'", opts.Triple);
482       LLDB_LOGV(log, "CPU: '{0}'", opts.CPU);
483       LLDB_LOGV(log, "FPMath: '{0}'", opts.FPMath);
484       LLDB_LOGV(log, "ABI: '{0}'", opts.ABI);
485       LLDB_LOGV(log, "LinkerVersion: '{0}'", opts.LinkerVersion);
486       StringList::LogDump(log, opts.FeaturesAsWritten, "FeaturesAsWritten");
487       StringList::LogDump(log, opts.Features, "Features");
488     }
489 
490   // 4. Create and install the target on the compiler.
491   m_compiler->createDiagnostics();
492   // Limit the number of error diagnostics we emit.
493   // A value of 0 means no limit for both LLDB and Clang.
494   m_compiler->getDiagnostics().setErrorLimit(target_sp->GetExprErrorLimit());
495 
496   auto target_info = TargetInfo::CreateTargetInfo(
497       m_compiler->getDiagnostics(), m_compiler->getInvocation().TargetOpts);
498   if (log) {
499     LLDB_LOGF(log, "Using SIMD alignment: %d",
500               target_info->getSimdDefaultAlign());
501     LLDB_LOGF(log, "Target datalayout string: '%s'",
502               target_info->getDataLayout().getStringRepresentation().c_str());
503     LLDB_LOGF(log, "Target ABI: '%s'", target_info->getABI().str().c_str());
504     LLDB_LOGF(log, "Target vector alignment: %d",
505               target_info->getMaxVectorAlign());
506   }
507   m_compiler->setTarget(target_info);
508 
509   assert(m_compiler->hasTarget());
510 
511   // 5. Set language options.
512   lldb::LanguageType language = expr.Language();
513   LangOptions &lang_opts = m_compiler->getLangOpts();
514 
515   switch (language) {
516   case lldb::eLanguageTypeC:
517   case lldb::eLanguageTypeC89:
518   case lldb::eLanguageTypeC99:
519   case lldb::eLanguageTypeC11:
520     // FIXME: the following language option is a temporary workaround,
521     // to "ask for C, get C++."
522     // For now, the expression parser must use C++ anytime the language is a C
523     // family language, because the expression parser uses features of C++ to
524     // capture values.
525     lang_opts.CPlusPlus = true;
526     break;
527   case lldb::eLanguageTypeObjC:
528     lang_opts.ObjC = true;
529     // FIXME: the following language option is a temporary workaround,
530     // to "ask for ObjC, get ObjC++" (see comment above).
531     lang_opts.CPlusPlus = true;
532 
533     // Clang now sets as default C++14 as the default standard (with
534     // GNU extensions), so we do the same here to avoid mismatches that
535     // cause compiler error when evaluating expressions (e.g. nullptr not found
536     // as it's a C++11 feature). Currently lldb evaluates C++14 as C++11 (see
537     // two lines below) so we decide to be consistent with that, but this could
538     // be re-evaluated in the future.
539     lang_opts.CPlusPlus11 = true;
540     break;
541   case lldb::eLanguageTypeC_plus_plus:
542   case lldb::eLanguageTypeC_plus_plus_11:
543   case lldb::eLanguageTypeC_plus_plus_14:
544     lang_opts.CPlusPlus11 = true;
545     m_compiler->getHeaderSearchOpts().UseLibcxx = true;
546     LLVM_FALLTHROUGH;
547   case lldb::eLanguageTypeC_plus_plus_03:
548     lang_opts.CPlusPlus = true;
549     if (process_sp)
550       lang_opts.ObjC =
551           process_sp->GetLanguageRuntime(lldb::eLanguageTypeObjC) != nullptr;
552     break;
553   case lldb::eLanguageTypeObjC_plus_plus:
554   case lldb::eLanguageTypeUnknown:
555   default:
556     lang_opts.ObjC = true;
557     lang_opts.CPlusPlus = true;
558     lang_opts.CPlusPlus11 = true;
559     m_compiler->getHeaderSearchOpts().UseLibcxx = true;
560     break;
561   }
562 
563   lang_opts.Bool = true;
564   lang_opts.WChar = true;
565   lang_opts.Blocks = true;
566   lang_opts.DebuggerSupport =
567       true; // Features specifically for debugger clients
568   if (expr.DesiredResultType() == Expression::eResultTypeId)
569     lang_opts.DebuggerCastResultToId = true;
570 
571   lang_opts.CharIsSigned = ArchSpec(m_compiler->getTargetOpts().Triple.c_str())
572                                .CharIsSignedByDefault();
573 
574   // Spell checking is a nice feature, but it ends up completing a lot of types
575   // that we didn't strictly speaking need to complete. As a result, we spend a
576   // long time parsing and importing debug information.
577   lang_opts.SpellChecking = false;
578 
579   auto *clang_expr = dyn_cast<ClangUserExpression>(&m_expr);
580   if (clang_expr && clang_expr->DidImportCxxModules()) {
581     LLDB_LOG(log, "Adding lang options for importing C++ modules");
582 
583     lang_opts.Modules = true;
584     // We want to implicitly build modules.
585     lang_opts.ImplicitModules = true;
586     // To automatically import all submodules when we import 'std'.
587     lang_opts.ModulesLocalVisibility = false;
588 
589     // We use the @import statements, so we need this:
590     // FIXME: We could use the modules-ts, but that currently doesn't work.
591     lang_opts.ObjC = true;
592 
593     // Options we need to parse libc++ code successfully.
594     // FIXME: We should ask the driver for the appropriate default flags.
595     lang_opts.GNUMode = true;
596     lang_opts.GNUKeywords = true;
597     lang_opts.DoubleSquareBracketAttributes = true;
598     lang_opts.CPlusPlus11 = true;
599 
600     // The Darwin libc expects this macro to be set.
601     lang_opts.GNUCVersion = 40201;
602 
603     SetupModuleHeaderPaths(m_compiler.get(), m_include_directories,
604                            target_sp);
605   }
606 
607   if (process_sp && lang_opts.ObjC) {
608     if (auto *runtime = ObjCLanguageRuntime::Get(*process_sp)) {
609       if (runtime->GetRuntimeVersion() ==
610           ObjCLanguageRuntime::ObjCRuntimeVersions::eAppleObjC_V2)
611         lang_opts.ObjCRuntime.set(ObjCRuntime::MacOSX, VersionTuple(10, 7));
612       else
613         lang_opts.ObjCRuntime.set(ObjCRuntime::FragileMacOSX,
614                                   VersionTuple(10, 7));
615 
616       if (runtime->HasNewLiteralsAndIndexing())
617         lang_opts.DebuggerObjCLiteral = true;
618     }
619   }
620 
621   lang_opts.ThreadsafeStatics = false;
622   lang_opts.AccessControl = false; // Debuggers get universal access
623   lang_opts.DollarIdents = true;   // $ indicates a persistent variable name
624   // We enable all builtin functions beside the builtins from libc/libm (e.g.
625   // 'fopen'). Those libc functions are already correctly handled by LLDB, and
626   // additionally enabling them as expandable builtins is breaking Clang.
627   lang_opts.NoBuiltin = true;
628 
629   // Set CodeGen options
630   m_compiler->getCodeGenOpts().EmitDeclMetadata = true;
631   m_compiler->getCodeGenOpts().InstrumentFunctions = false;
632   m_compiler->getCodeGenOpts().setFramePointer(
633                                     CodeGenOptions::FramePointerKind::All);
634   if (generate_debug_info)
635     m_compiler->getCodeGenOpts().setDebugInfo(codegenoptions::FullDebugInfo);
636   else
637     m_compiler->getCodeGenOpts().setDebugInfo(codegenoptions::NoDebugInfo);
638 
639   // Disable some warnings.
640   m_compiler->getDiagnostics().setSeverityForGroup(
641       clang::diag::Flavor::WarningOrError, "unused-value",
642       clang::diag::Severity::Ignored, SourceLocation());
643   m_compiler->getDiagnostics().setSeverityForGroup(
644       clang::diag::Flavor::WarningOrError, "odr",
645       clang::diag::Severity::Ignored, SourceLocation());
646 
647   // Inform the target of the language options
648   //
649   // FIXME: We shouldn't need to do this, the target should be immutable once
650   // created. This complexity should be lifted elsewhere.
651   m_compiler->getTarget().adjust(m_compiler->getLangOpts());
652 
653   // 6. Set up the diagnostic buffer for reporting errors
654 
655   auto diag_mgr = new ClangDiagnosticManagerAdapter(
656       m_compiler->getDiagnostics().getDiagnosticOptions());
657   m_compiler->getDiagnostics().setClient(diag_mgr);
658 
659   // 7. Set up the source management objects inside the compiler
660   m_compiler->createFileManager();
661   if (!m_compiler->hasSourceManager())
662     m_compiler->createSourceManager(m_compiler->getFileManager());
663   m_compiler->createPreprocessor(TU_Complete);
664 
665   switch (language) {
666   case lldb::eLanguageTypeC:
667   case lldb::eLanguageTypeC89:
668   case lldb::eLanguageTypeC99:
669   case lldb::eLanguageTypeC11:
670   case lldb::eLanguageTypeObjC:
671     // This is not a C++ expression but we enabled C++ as explained above.
672     // Remove all C++ keywords from the PP so that the user can still use
673     // variables that have C++ keywords as names (e.g. 'int template;').
674     RemoveAllCppKeywords(m_compiler->getPreprocessor().getIdentifierTable());
675     break;
676   default:
677     break;
678   }
679 
680   if (ClangModulesDeclVendor *decl_vendor =
681           target_sp->GetClangModulesDeclVendor()) {
682     if (auto *clang_persistent_vars = llvm::cast<ClangPersistentVariables>(
683             target_sp->GetPersistentExpressionStateForLanguage(
684                 lldb::eLanguageTypeC))) {
685       std::unique_ptr<PPCallbacks> pp_callbacks(
686           new LLDBPreprocessorCallbacks(*decl_vendor, *clang_persistent_vars,
687                                         m_compiler->getSourceManager()));
688       m_pp_callbacks =
689           static_cast<LLDBPreprocessorCallbacks *>(pp_callbacks.get());
690       m_compiler->getPreprocessor().addPPCallbacks(std::move(pp_callbacks));
691     }
692   }
693 
694   // 8. Most of this we get from the CompilerInstance, but we also want to give
695   // the context an ExternalASTSource.
696 
697   auto &PP = m_compiler->getPreprocessor();
698   auto &builtin_context = PP.getBuiltinInfo();
699   builtin_context.initializeBuiltins(PP.getIdentifierTable(),
700                                      m_compiler->getLangOpts());
701 
702   m_compiler->createASTContext();
703   clang::ASTContext &ast_context = m_compiler->getASTContext();
704 
705   m_ast_context = std::make_unique<TypeSystemClang>(
706       "Expression ASTContext for '" + m_filename + "'", ast_context);
707 
708   std::string module_name("$__lldb_module");
709 
710   m_llvm_context = std::make_unique<LLVMContext>();
711   m_code_generator.reset(CreateLLVMCodeGen(
712       m_compiler->getDiagnostics(), module_name,
713       m_compiler->getHeaderSearchOpts(), m_compiler->getPreprocessorOpts(),
714       m_compiler->getCodeGenOpts(), *m_llvm_context));
715 }
716 
~ClangExpressionParser()717 ClangExpressionParser::~ClangExpressionParser() {}
718 
719 namespace {
720 
721 /// \class CodeComplete
722 ///
723 /// A code completion consumer for the clang Sema that is responsible for
724 /// creating the completion suggestions when a user requests completion
725 /// of an incomplete `expr` invocation.
726 class CodeComplete : public CodeCompleteConsumer {
727   CodeCompletionTUInfo m_info;
728 
729   std::string m_expr;
730   unsigned m_position = 0;
731   /// The printing policy we use when printing declarations for our completion
732   /// descriptions.
733   clang::PrintingPolicy m_desc_policy;
734 
735   struct CompletionWithPriority {
736     CompletionResult::Completion completion;
737     /// See CodeCompletionResult::Priority;
738     unsigned Priority;
739 
740     /// Establishes a deterministic order in a list of CompletionWithPriority.
741     /// The order returned here is the order in which the completions are
742     /// displayed to the user.
operator <__anon57ee7a770111::CodeComplete::CompletionWithPriority743     bool operator<(const CompletionWithPriority &o) const {
744       // High priority results should come first.
745       if (Priority != o.Priority)
746         return Priority > o.Priority;
747 
748       // Identical priority, so just make sure it's a deterministic order.
749       return completion.GetUniqueKey() < o.completion.GetUniqueKey();
750     }
751   };
752 
753   /// The stored completions.
754   /// Warning: These are in a non-deterministic order until they are sorted
755   /// and returned back to the caller.
756   std::vector<CompletionWithPriority> m_completions;
757 
758   /// Returns true if the given character can be used in an identifier.
759   /// This also returns true for numbers because for completion we usually
760   /// just iterate backwards over iterators.
761   ///
762   /// Note: lldb uses '$' in its internal identifiers, so we also allow this.
IsIdChar(char c)763   static bool IsIdChar(char c) {
764     return c == '_' || std::isalnum(c) || c == '$';
765   }
766 
767   /// Returns true if the given character is used to separate arguments
768   /// in the command line of lldb.
IsTokenSeparator(char c)769   static bool IsTokenSeparator(char c) { return c == ' ' || c == '\t'; }
770 
771   /// Drops all tokens in front of the expression that are unrelated for
772   /// the completion of the cmd line. 'unrelated' means here that the token
773   /// is not interested for the lldb completion API result.
dropUnrelatedFrontTokens(StringRef cmd) const774   StringRef dropUnrelatedFrontTokens(StringRef cmd) const {
775     if (cmd.empty())
776       return cmd;
777 
778     // If we are at the start of a word, then all tokens are unrelated to
779     // the current completion logic.
780     if (IsTokenSeparator(cmd.back()))
781       return StringRef();
782 
783     // Remove all previous tokens from the string as they are unrelated
784     // to completing the current token.
785     StringRef to_remove = cmd;
786     while (!to_remove.empty() && !IsTokenSeparator(to_remove.back())) {
787       to_remove = to_remove.drop_back();
788     }
789     cmd = cmd.drop_front(to_remove.size());
790 
791     return cmd;
792   }
793 
794   /// Removes the last identifier token from the given cmd line.
removeLastToken(StringRef cmd) const795   StringRef removeLastToken(StringRef cmd) const {
796     while (!cmd.empty() && IsIdChar(cmd.back())) {
797       cmd = cmd.drop_back();
798     }
799     return cmd;
800   }
801 
802   /// Attempts to merge the given completion from the given position into the
803   /// existing command. Returns the completion string that can be returned to
804   /// the lldb completion API.
mergeCompletion(StringRef existing,unsigned pos,StringRef completion) const805   std::string mergeCompletion(StringRef existing, unsigned pos,
806                               StringRef completion) const {
807     StringRef existing_command = existing.substr(0, pos);
808     // We rewrite the last token with the completion, so let's drop that
809     // token from the command.
810     existing_command = removeLastToken(existing_command);
811     // We also should remove all previous tokens from the command as they
812     // would otherwise be added to the completion that already has the
813     // completion.
814     existing_command = dropUnrelatedFrontTokens(existing_command);
815     return existing_command.str() + completion.str();
816   }
817 
818 public:
819   /// Constructs a CodeComplete consumer that can be attached to a Sema.
820   ///
821   /// \param[out] expr
822   ///    The whole expression string that we are currently parsing. This
823   ///    string needs to be equal to the input the user typed, and NOT the
824   ///    final code that Clang is parsing.
825   /// \param[out] position
826   ///    The character position of the user cursor in the `expr` parameter.
827   ///
CodeComplete(clang::LangOptions ops,std::string expr,unsigned position)828   CodeComplete(clang::LangOptions ops, std::string expr, unsigned position)
829       : CodeCompleteConsumer(CodeCompleteOptions()),
830         m_info(std::make_shared<GlobalCodeCompletionAllocator>()), m_expr(expr),
831         m_position(position), m_desc_policy(ops) {
832 
833     // Ensure that the printing policy is producing a description that is as
834     // short as possible.
835     m_desc_policy.SuppressScope = true;
836     m_desc_policy.SuppressTagKeyword = true;
837     m_desc_policy.FullyQualifiedName = false;
838     m_desc_policy.TerseOutput = true;
839     m_desc_policy.IncludeNewlines = false;
840     m_desc_policy.UseVoidForZeroParams = false;
841     m_desc_policy.Bool = true;
842   }
843 
844   /// \name Code-completion filtering
845   /// Check if the result should be filtered out.
isResultFilteredOut(StringRef Filter,CodeCompletionResult Result)846   bool isResultFilteredOut(StringRef Filter,
847                            CodeCompletionResult Result) override {
848     // This code is mostly copied from CodeCompleteConsumer.
849     switch (Result.Kind) {
850     case CodeCompletionResult::RK_Declaration:
851       return !(
852           Result.Declaration->getIdentifier() &&
853           Result.Declaration->getIdentifier()->getName().startswith(Filter));
854     case CodeCompletionResult::RK_Keyword:
855       return !StringRef(Result.Keyword).startswith(Filter);
856     case CodeCompletionResult::RK_Macro:
857       return !Result.Macro->getName().startswith(Filter);
858     case CodeCompletionResult::RK_Pattern:
859       return !StringRef(Result.Pattern->getAsString()).startswith(Filter);
860     }
861     // If we trigger this assert or the above switch yields a warning, then
862     // CodeCompletionResult has been enhanced with more kinds of completion
863     // results. Expand the switch above in this case.
864     assert(false && "Unknown completion result type?");
865     // If we reach this, then we should just ignore whatever kind of unknown
866     // result we got back. We probably can't turn it into any kind of useful
867     // completion suggestion with the existing code.
868     return true;
869   }
870 
871 private:
872   /// Generate the completion strings for the given CodeCompletionResult.
873   /// Note that this function has to process results that could come in
874   /// non-deterministic order, so this function should have no side effects.
875   /// To make this easier to enforce, this function and all its parameters
876   /// should always be const-qualified.
877   /// \return Returns llvm::None if no completion should be provided for the
878   ///         given CodeCompletionResult.
879   llvm::Optional<CompletionWithPriority>
getCompletionForResult(const CodeCompletionResult & R) const880   getCompletionForResult(const CodeCompletionResult &R) const {
881     std::string ToInsert;
882     std::string Description;
883     // Handle the different completion kinds that come from the Sema.
884     switch (R.Kind) {
885     case CodeCompletionResult::RK_Declaration: {
886       const NamedDecl *D = R.Declaration;
887       ToInsert = R.Declaration->getNameAsString();
888       // If we have a function decl that has no arguments we want to
889       // complete the empty parantheses for the user. If the function has
890       // arguments, we at least complete the opening bracket.
891       if (const FunctionDecl *F = dyn_cast<FunctionDecl>(D)) {
892         if (F->getNumParams() == 0)
893           ToInsert += "()";
894         else
895           ToInsert += "(";
896         raw_string_ostream OS(Description);
897         F->print(OS, m_desc_policy, false);
898         OS.flush();
899       } else if (const VarDecl *V = dyn_cast<VarDecl>(D)) {
900         Description = V->getType().getAsString(m_desc_policy);
901       } else if (const FieldDecl *F = dyn_cast<FieldDecl>(D)) {
902         Description = F->getType().getAsString(m_desc_policy);
903       } else if (const NamespaceDecl *N = dyn_cast<NamespaceDecl>(D)) {
904         // If we try to complete a namespace, then we can directly append
905         // the '::'.
906         if (!N->isAnonymousNamespace())
907           ToInsert += "::";
908       }
909       break;
910     }
911     case CodeCompletionResult::RK_Keyword:
912       ToInsert = R.Keyword;
913       break;
914     case CodeCompletionResult::RK_Macro:
915       ToInsert = R.Macro->getName().str();
916       break;
917     case CodeCompletionResult::RK_Pattern:
918       ToInsert = R.Pattern->getTypedText();
919       break;
920     }
921     // We also filter some internal lldb identifiers here. The user
922     // shouldn't see these.
923     if (llvm::StringRef(ToInsert).startswith("$__lldb_"))
924       return llvm::None;
925     if (ToInsert.empty())
926       return llvm::None;
927     // Merge the suggested Token into the existing command line to comply
928     // with the kind of result the lldb API expects.
929     std::string CompletionSuggestion =
930         mergeCompletion(m_expr, m_position, ToInsert);
931 
932     CompletionResult::Completion completion(CompletionSuggestion, Description,
933                                             CompletionMode::Normal);
934     return {{completion, R.Priority}};
935   }
936 
937 public:
938   /// Adds the completions to the given CompletionRequest.
GetCompletions(CompletionRequest & request)939   void GetCompletions(CompletionRequest &request) {
940     // Bring m_completions into a deterministic order and pass it on to the
941     // CompletionRequest.
942     llvm::sort(m_completions);
943 
944     for (const CompletionWithPriority &C : m_completions)
945       request.AddCompletion(C.completion.GetCompletion(),
946                             C.completion.GetDescription(),
947                             C.completion.GetMode());
948   }
949 
950   /// \name Code-completion callbacks
951   /// Process the finalized code-completion results.
ProcessCodeCompleteResults(Sema & SemaRef,CodeCompletionContext Context,CodeCompletionResult * Results,unsigned NumResults)952   void ProcessCodeCompleteResults(Sema &SemaRef, CodeCompletionContext Context,
953                                   CodeCompletionResult *Results,
954                                   unsigned NumResults) override {
955 
956     // The Sema put the incomplete token we try to complete in here during
957     // lexing, so we need to retrieve it here to know what we are completing.
958     StringRef Filter = SemaRef.getPreprocessor().getCodeCompletionFilter();
959 
960     // Iterate over all the results. Filter out results we don't want and
961     // process the rest.
962     for (unsigned I = 0; I != NumResults; ++I) {
963       // Filter the results with the information from the Sema.
964       if (!Filter.empty() && isResultFilteredOut(Filter, Results[I]))
965         continue;
966 
967       CodeCompletionResult &R = Results[I];
968       llvm::Optional<CompletionWithPriority> CompletionAndPriority =
969           getCompletionForResult(R);
970       if (!CompletionAndPriority)
971         continue;
972       m_completions.push_back(*CompletionAndPriority);
973     }
974   }
975 
976   /// \param S the semantic-analyzer object for which code-completion is being
977   /// done.
978   ///
979   /// \param CurrentArg the index of the current argument.
980   ///
981   /// \param Candidates an array of overload candidates.
982   ///
983   /// \param NumCandidates the number of overload candidates
ProcessOverloadCandidates(Sema & S,unsigned CurrentArg,OverloadCandidate * Candidates,unsigned NumCandidates,SourceLocation OpenParLoc)984   void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
985                                  OverloadCandidate *Candidates,
986                                  unsigned NumCandidates,
987                                  SourceLocation OpenParLoc) override {
988     // At the moment we don't filter out any overloaded candidates.
989   }
990 
getAllocator()991   CodeCompletionAllocator &getAllocator() override {
992     return m_info.getAllocator();
993   }
994 
getCodeCompletionTUInfo()995   CodeCompletionTUInfo &getCodeCompletionTUInfo() override { return m_info; }
996 };
997 } // namespace
998 
Complete(CompletionRequest & request,unsigned line,unsigned pos,unsigned typed_pos)999 bool ClangExpressionParser::Complete(CompletionRequest &request, unsigned line,
1000                                      unsigned pos, unsigned typed_pos) {
1001   DiagnosticManager mgr;
1002   // We need the raw user expression here because that's what the CodeComplete
1003   // class uses to provide completion suggestions.
1004   // However, the `Text` method only gives us the transformed expression here.
1005   // To actually get the raw user input here, we have to cast our expression to
1006   // the LLVMUserExpression which exposes the right API. This should never fail
1007   // as we always have a ClangUserExpression whenever we call this.
1008   ClangUserExpression *llvm_expr = cast<ClangUserExpression>(&m_expr);
1009   CodeComplete CC(m_compiler->getLangOpts(), llvm_expr->GetUserText(),
1010                   typed_pos);
1011   // We don't need a code generator for parsing.
1012   m_code_generator.reset();
1013   // Start parsing the expression with our custom code completion consumer.
1014   ParseInternal(mgr, &CC, line, pos);
1015   CC.GetCompletions(request);
1016   return true;
1017 }
1018 
Parse(DiagnosticManager & diagnostic_manager)1019 unsigned ClangExpressionParser::Parse(DiagnosticManager &diagnostic_manager) {
1020   return ParseInternal(diagnostic_manager);
1021 }
1022 
1023 unsigned
ParseInternal(DiagnosticManager & diagnostic_manager,CodeCompleteConsumer * completion_consumer,unsigned completion_line,unsigned completion_column)1024 ClangExpressionParser::ParseInternal(DiagnosticManager &diagnostic_manager,
1025                                      CodeCompleteConsumer *completion_consumer,
1026                                      unsigned completion_line,
1027                                      unsigned completion_column) {
1028   ClangDiagnosticManagerAdapter *adapter =
1029       static_cast<ClangDiagnosticManagerAdapter *>(
1030           m_compiler->getDiagnostics().getClient());
1031 
1032   adapter->ResetManager(&diagnostic_manager);
1033 
1034   const char *expr_text = m_expr.Text();
1035 
1036   clang::SourceManager &source_mgr = m_compiler->getSourceManager();
1037   bool created_main_file = false;
1038 
1039   // Clang wants to do completion on a real file known by Clang's file manager,
1040   // so we have to create one to make this work.
1041   // TODO: We probably could also simulate to Clang's file manager that there
1042   // is a real file that contains our code.
1043   bool should_create_file = completion_consumer != nullptr;
1044 
1045   // We also want a real file on disk if we generate full debug info.
1046   should_create_file |= m_compiler->getCodeGenOpts().getDebugInfo() ==
1047                         codegenoptions::FullDebugInfo;
1048 
1049   if (should_create_file) {
1050     int temp_fd = -1;
1051     llvm::SmallString<128> result_path;
1052     if (FileSpec tmpdir_file_spec = HostInfo::GetProcessTempDir()) {
1053       tmpdir_file_spec.AppendPathComponent("lldb-%%%%%%.expr");
1054       std::string temp_source_path = tmpdir_file_spec.GetPath();
1055       llvm::sys::fs::createUniqueFile(temp_source_path, temp_fd, result_path);
1056     } else {
1057       llvm::sys::fs::createTemporaryFile("lldb", "expr", temp_fd, result_path);
1058     }
1059 
1060     if (temp_fd != -1) {
1061       lldb_private::NativeFile file(temp_fd, File::eOpenOptionWrite, true);
1062       const size_t expr_text_len = strlen(expr_text);
1063       size_t bytes_written = expr_text_len;
1064       if (file.Write(expr_text, bytes_written).Success()) {
1065         if (bytes_written == expr_text_len) {
1066           file.Close();
1067           if (auto fileEntry =
1068                   m_compiler->getFileManager().getFile(result_path)) {
1069             source_mgr.setMainFileID(source_mgr.createFileID(
1070                 *fileEntry,
1071                 SourceLocation(), SrcMgr::C_User));
1072             created_main_file = true;
1073           }
1074         }
1075       }
1076     }
1077   }
1078 
1079   if (!created_main_file) {
1080     std::unique_ptr<MemoryBuffer> memory_buffer =
1081         MemoryBuffer::getMemBufferCopy(expr_text, m_filename);
1082     source_mgr.setMainFileID(source_mgr.createFileID(std::move(memory_buffer)));
1083   }
1084 
1085   adapter->BeginSourceFile(m_compiler->getLangOpts(),
1086                            &m_compiler->getPreprocessor());
1087 
1088   ClangExpressionHelper *type_system_helper =
1089       dyn_cast<ClangExpressionHelper>(m_expr.GetTypeSystemHelper());
1090 
1091   // If we want to parse for code completion, we need to attach our code
1092   // completion consumer to the Sema and specify a completion position.
1093   // While parsing the Sema will call this consumer with the provided
1094   // completion suggestions.
1095   if (completion_consumer) {
1096     auto main_file = source_mgr.getFileEntryForID(source_mgr.getMainFileID());
1097     auto &PP = m_compiler->getPreprocessor();
1098     // Lines and columns start at 1 in Clang, but code completion positions are
1099     // indexed from 0, so we need to add 1 to the line and column here.
1100     ++completion_line;
1101     ++completion_column;
1102     PP.SetCodeCompletionPoint(main_file, completion_line, completion_column);
1103   }
1104 
1105   ASTConsumer *ast_transformer =
1106       type_system_helper->ASTTransformer(m_code_generator.get());
1107 
1108   std::unique_ptr<clang::ASTConsumer> Consumer;
1109   if (ast_transformer) {
1110     Consumer = std::make_unique<ASTConsumerForwarder>(ast_transformer);
1111   } else if (m_code_generator) {
1112     Consumer = std::make_unique<ASTConsumerForwarder>(m_code_generator.get());
1113   } else {
1114     Consumer = std::make_unique<ASTConsumer>();
1115   }
1116 
1117   clang::ASTContext &ast_context = m_compiler->getASTContext();
1118 
1119   m_compiler->setSema(new Sema(m_compiler->getPreprocessor(), ast_context,
1120                                *Consumer, TU_Complete, completion_consumer));
1121   m_compiler->setASTConsumer(std::move(Consumer));
1122 
1123   if (ast_context.getLangOpts().Modules) {
1124     m_compiler->createASTReader();
1125     m_ast_context->setSema(&m_compiler->getSema());
1126   }
1127 
1128   ClangExpressionDeclMap *decl_map = type_system_helper->DeclMap();
1129   if (decl_map) {
1130     decl_map->InstallCodeGenerator(&m_compiler->getASTConsumer());
1131     decl_map->InstallDiagnosticManager(diagnostic_manager);
1132 
1133     clang::ExternalASTSource *ast_source = decl_map->CreateProxy();
1134 
1135     if (ast_context.getExternalSource()) {
1136       auto module_wrapper =
1137           new ExternalASTSourceWrapper(ast_context.getExternalSource());
1138 
1139       auto ast_source_wrapper = new ExternalASTSourceWrapper(ast_source);
1140 
1141       auto multiplexer =
1142           new SemaSourceWithPriorities(*module_wrapper, *ast_source_wrapper);
1143       IntrusiveRefCntPtr<ExternalASTSource> Source(multiplexer);
1144       ast_context.setExternalSource(Source);
1145     } else {
1146       ast_context.setExternalSource(ast_source);
1147     }
1148     decl_map->InstallASTContext(*m_ast_context);
1149   }
1150 
1151   // Check that the ASTReader is properly attached to ASTContext and Sema.
1152   if (ast_context.getLangOpts().Modules) {
1153     assert(m_compiler->getASTContext().getExternalSource() &&
1154            "ASTContext doesn't know about the ASTReader?");
1155     assert(m_compiler->getSema().getExternalSource() &&
1156            "Sema doesn't know about the ASTReader?");
1157   }
1158 
1159   {
1160     llvm::CrashRecoveryContextCleanupRegistrar<Sema> CleanupSema(
1161         &m_compiler->getSema());
1162     ParseAST(m_compiler->getSema(), false, false);
1163   }
1164 
1165   // Make sure we have no pointer to the Sema we are about to destroy.
1166   if (ast_context.getLangOpts().Modules)
1167     m_ast_context->setSema(nullptr);
1168   // Destroy the Sema. This is necessary because we want to emulate the
1169   // original behavior of ParseAST (which also destroys the Sema after parsing).
1170   m_compiler->setSema(nullptr);
1171 
1172   adapter->EndSourceFile();
1173 
1174   unsigned num_errors = adapter->getNumErrors();
1175 
1176   if (m_pp_callbacks && m_pp_callbacks->hasErrors()) {
1177     num_errors++;
1178     diagnostic_manager.PutString(eDiagnosticSeverityError,
1179                                  "while importing modules:");
1180     diagnostic_manager.AppendMessageToDiagnostic(
1181         m_pp_callbacks->getErrorString());
1182   }
1183 
1184   if (!num_errors) {
1185     type_system_helper->CommitPersistentDecls();
1186   }
1187 
1188   adapter->ResetManager();
1189 
1190   return num_errors;
1191 }
1192 
1193 std::string
GetClangTargetABI(const ArchSpec & target_arch)1194 ClangExpressionParser::GetClangTargetABI(const ArchSpec &target_arch) {
1195   std::string abi;
1196 
1197   if (target_arch.IsMIPS()) {
1198     switch (target_arch.GetFlags() & ArchSpec::eMIPSABI_mask) {
1199     case ArchSpec::eMIPSABI_N64:
1200       abi = "n64";
1201       break;
1202     case ArchSpec::eMIPSABI_N32:
1203       abi = "n32";
1204       break;
1205     case ArchSpec::eMIPSABI_O32:
1206       abi = "o32";
1207       break;
1208     default:
1209       break;
1210     }
1211   }
1212   return abi;
1213 }
1214 
1215 /// Applies the given Fix-It hint to the given commit.
ApplyFixIt(const FixItHint & fixit,clang::edit::Commit & commit)1216 static void ApplyFixIt(const FixItHint &fixit, clang::edit::Commit &commit) {
1217   // This is cobbed from clang::Rewrite::FixItRewriter.
1218   if (fixit.CodeToInsert.empty()) {
1219     if (fixit.InsertFromRange.isValid()) {
1220       commit.insertFromRange(fixit.RemoveRange.getBegin(),
1221                              fixit.InsertFromRange, /*afterToken=*/false,
1222                              fixit.BeforePreviousInsertions);
1223       return;
1224     }
1225     commit.remove(fixit.RemoveRange);
1226     return;
1227   }
1228   if (fixit.RemoveRange.isTokenRange() ||
1229       fixit.RemoveRange.getBegin() != fixit.RemoveRange.getEnd()) {
1230     commit.replace(fixit.RemoveRange, fixit.CodeToInsert);
1231     return;
1232   }
1233   commit.insert(fixit.RemoveRange.getBegin(), fixit.CodeToInsert,
1234                 /*afterToken=*/false, fixit.BeforePreviousInsertions);
1235 }
1236 
RewriteExpression(DiagnosticManager & diagnostic_manager)1237 bool ClangExpressionParser::RewriteExpression(
1238     DiagnosticManager &diagnostic_manager) {
1239   clang::SourceManager &source_manager = m_compiler->getSourceManager();
1240   clang::edit::EditedSource editor(source_manager, m_compiler->getLangOpts(),
1241                                    nullptr);
1242   clang::edit::Commit commit(editor);
1243   clang::Rewriter rewriter(source_manager, m_compiler->getLangOpts());
1244 
1245   class RewritesReceiver : public edit::EditsReceiver {
1246     Rewriter &rewrite;
1247 
1248   public:
1249     RewritesReceiver(Rewriter &in_rewrite) : rewrite(in_rewrite) {}
1250 
1251     void insert(SourceLocation loc, StringRef text) override {
1252       rewrite.InsertText(loc, text);
1253     }
1254     void replace(CharSourceRange range, StringRef text) override {
1255       rewrite.ReplaceText(range.getBegin(), rewrite.getRangeSize(range), text);
1256     }
1257   };
1258 
1259   RewritesReceiver rewrites_receiver(rewriter);
1260 
1261   const DiagnosticList &diagnostics = diagnostic_manager.Diagnostics();
1262   size_t num_diags = diagnostics.size();
1263   if (num_diags == 0)
1264     return false;
1265 
1266   for (const auto &diag : diagnostic_manager.Diagnostics()) {
1267     const auto *diagnostic = llvm::dyn_cast<ClangDiagnostic>(diag.get());
1268     if (!diagnostic)
1269       continue;
1270     if (!diagnostic->HasFixIts())
1271       continue;
1272     for (const FixItHint &fixit : diagnostic->FixIts())
1273       ApplyFixIt(fixit, commit);
1274   }
1275 
1276   // FIXME - do we want to try to propagate specific errors here?
1277   if (!commit.isCommitable())
1278     return false;
1279   else if (!editor.commit(commit))
1280     return false;
1281 
1282   // Now play all the edits, and stash the result in the diagnostic manager.
1283   editor.applyRewrites(rewrites_receiver);
1284   RewriteBuffer &main_file_buffer =
1285       rewriter.getEditBuffer(source_manager.getMainFileID());
1286 
1287   std::string fixed_expression;
1288   llvm::raw_string_ostream out_stream(fixed_expression);
1289 
1290   main_file_buffer.write(out_stream);
1291   out_stream.flush();
1292   diagnostic_manager.SetFixedExpression(fixed_expression);
1293 
1294   return true;
1295 }
1296 
FindFunctionInModule(ConstString & mangled_name,llvm::Module * module,const char * orig_name)1297 static bool FindFunctionInModule(ConstString &mangled_name,
1298                                  llvm::Module *module, const char *orig_name) {
1299   for (const auto &func : module->getFunctionList()) {
1300     const StringRef &name = func.getName();
1301     if (name.find(orig_name) != StringRef::npos) {
1302       mangled_name.SetString(name);
1303       return true;
1304     }
1305   }
1306 
1307   return false;
1308 }
1309 
PrepareForExecution(lldb::addr_t & func_addr,lldb::addr_t & func_end,lldb::IRExecutionUnitSP & execution_unit_sp,ExecutionContext & exe_ctx,bool & can_interpret,ExecutionPolicy execution_policy)1310 lldb_private::Status ClangExpressionParser::PrepareForExecution(
1311     lldb::addr_t &func_addr, lldb::addr_t &func_end,
1312     lldb::IRExecutionUnitSP &execution_unit_sp, ExecutionContext &exe_ctx,
1313     bool &can_interpret, ExecutionPolicy execution_policy) {
1314   func_addr = LLDB_INVALID_ADDRESS;
1315   func_end = LLDB_INVALID_ADDRESS;
1316   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
1317 
1318   lldb_private::Status err;
1319 
1320   std::unique_ptr<llvm::Module> llvm_module_up(
1321       m_code_generator->ReleaseModule());
1322 
1323   if (!llvm_module_up) {
1324     err.SetErrorToGenericError();
1325     err.SetErrorString("IR doesn't contain a module");
1326     return err;
1327   }
1328 
1329   ConstString function_name;
1330 
1331   if (execution_policy != eExecutionPolicyTopLevel) {
1332     // Find the actual name of the function (it's often mangled somehow)
1333 
1334     if (!FindFunctionInModule(function_name, llvm_module_up.get(),
1335                               m_expr.FunctionName())) {
1336       err.SetErrorToGenericError();
1337       err.SetErrorStringWithFormat("Couldn't find %s() in the module",
1338                                    m_expr.FunctionName());
1339       return err;
1340     } else {
1341       LLDB_LOGF(log, "Found function %s for %s", function_name.AsCString(),
1342                 m_expr.FunctionName());
1343     }
1344   }
1345 
1346   SymbolContext sc;
1347 
1348   if (lldb::StackFrameSP frame_sp = exe_ctx.GetFrameSP()) {
1349     sc = frame_sp->GetSymbolContext(lldb::eSymbolContextEverything);
1350   } else if (lldb::TargetSP target_sp = exe_ctx.GetTargetSP()) {
1351     sc.target_sp = target_sp;
1352   }
1353 
1354   LLVMUserExpression::IRPasses custom_passes;
1355   {
1356     auto lang = m_expr.Language();
1357     LLDB_LOGF(log, "%s - Current expression language is %s\n", __FUNCTION__,
1358               Language::GetNameForLanguageType(lang));
1359     lldb::ProcessSP process_sp = exe_ctx.GetProcessSP();
1360     if (process_sp && lang != lldb::eLanguageTypeUnknown) {
1361       auto runtime = process_sp->GetLanguageRuntime(lang);
1362       if (runtime)
1363         runtime->GetIRPasses(custom_passes);
1364     }
1365   }
1366 
1367   if (custom_passes.EarlyPasses) {
1368     LLDB_LOGF(log,
1369               "%s - Running Early IR Passes from LanguageRuntime on "
1370               "expression module '%s'",
1371               __FUNCTION__, m_expr.FunctionName());
1372 
1373     custom_passes.EarlyPasses->run(*llvm_module_up);
1374   }
1375 
1376   execution_unit_sp = std::make_shared<IRExecutionUnit>(
1377       m_llvm_context, // handed off here
1378       llvm_module_up, // handed off here
1379       function_name, exe_ctx.GetTargetSP(), sc,
1380       m_compiler->getTargetOpts().Features);
1381 
1382   ClangExpressionHelper *type_system_helper =
1383       dyn_cast<ClangExpressionHelper>(m_expr.GetTypeSystemHelper());
1384   ClangExpressionDeclMap *decl_map =
1385       type_system_helper->DeclMap(); // result can be NULL
1386 
1387   if (decl_map) {
1388     StreamString error_stream;
1389     IRForTarget ir_for_target(decl_map, m_expr.NeedsVariableResolution(),
1390                               *execution_unit_sp, error_stream,
1391                               function_name.AsCString());
1392 
1393     if (!ir_for_target.runOnModule(*execution_unit_sp->GetModule())) {
1394       err.SetErrorString(error_stream.GetString());
1395       return err;
1396     }
1397 
1398     Process *process = exe_ctx.GetProcessPtr();
1399 
1400     if (execution_policy != eExecutionPolicyAlways &&
1401         execution_policy != eExecutionPolicyTopLevel) {
1402       lldb_private::Status interpret_error;
1403 
1404       bool interpret_function_calls =
1405           !process ? false : process->CanInterpretFunctionCalls();
1406       can_interpret = IRInterpreter::CanInterpret(
1407           *execution_unit_sp->GetModule(), *execution_unit_sp->GetFunction(),
1408           interpret_error, interpret_function_calls);
1409 
1410       if (!can_interpret && execution_policy == eExecutionPolicyNever) {
1411         err.SetErrorStringWithFormat(
1412             "Can't evaluate the expression without a running target due to: %s",
1413             interpret_error.AsCString());
1414         return err;
1415       }
1416     }
1417 
1418     if (!process && execution_policy == eExecutionPolicyAlways) {
1419       err.SetErrorString("Expression needed to run in the target, but the "
1420                          "target can't be run");
1421       return err;
1422     }
1423 
1424     if (!process && execution_policy == eExecutionPolicyTopLevel) {
1425       err.SetErrorString("Top-level code needs to be inserted into a runnable "
1426                          "target, but the target can't be run");
1427       return err;
1428     }
1429 
1430     if (execution_policy == eExecutionPolicyAlways ||
1431         (execution_policy != eExecutionPolicyTopLevel && !can_interpret)) {
1432       if (m_expr.NeedsValidation() && process) {
1433         if (!process->GetDynamicCheckers()) {
1434           ClangDynamicCheckerFunctions *dynamic_checkers =
1435               new ClangDynamicCheckerFunctions();
1436 
1437           DiagnosticManager install_diagnostics;
1438 
1439           if (!dynamic_checkers->Install(install_diagnostics, exe_ctx)) {
1440             if (install_diagnostics.Diagnostics().size())
1441               err.SetErrorString(install_diagnostics.GetString().c_str());
1442             else
1443               err.SetErrorString("couldn't install checkers, unknown error");
1444 
1445             return err;
1446           }
1447 
1448           process->SetDynamicCheckers(dynamic_checkers);
1449 
1450           LLDB_LOGF(log, "== [ClangExpressionParser::PrepareForExecution] "
1451                          "Finished installing dynamic checkers ==");
1452         }
1453 
1454         if (auto *checker_funcs = llvm::dyn_cast<ClangDynamicCheckerFunctions>(
1455                 process->GetDynamicCheckers())) {
1456           IRDynamicChecks ir_dynamic_checks(*checker_funcs,
1457                                             function_name.AsCString());
1458 
1459           llvm::Module *module = execution_unit_sp->GetModule();
1460           if (!module || !ir_dynamic_checks.runOnModule(*module)) {
1461             err.SetErrorToGenericError();
1462             err.SetErrorString("Couldn't add dynamic checks to the expression");
1463             return err;
1464           }
1465 
1466           if (custom_passes.LatePasses) {
1467             LLDB_LOGF(log,
1468                       "%s - Running Late IR Passes from LanguageRuntime on "
1469                       "expression module '%s'",
1470                       __FUNCTION__, m_expr.FunctionName());
1471 
1472             custom_passes.LatePasses->run(*module);
1473           }
1474         }
1475       }
1476     }
1477 
1478     if (execution_policy == eExecutionPolicyAlways ||
1479         execution_policy == eExecutionPolicyTopLevel || !can_interpret) {
1480       execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);
1481     }
1482   } else {
1483     execution_unit_sp->GetRunnableInfo(err, func_addr, func_end);
1484   }
1485 
1486   return err;
1487 }
1488 
RunStaticInitializers(lldb::IRExecutionUnitSP & execution_unit_sp,ExecutionContext & exe_ctx)1489 lldb_private::Status ClangExpressionParser::RunStaticInitializers(
1490     lldb::IRExecutionUnitSP &execution_unit_sp, ExecutionContext &exe_ctx) {
1491   lldb_private::Status err;
1492 
1493   lldbassert(execution_unit_sp.get());
1494   lldbassert(exe_ctx.HasThreadScope());
1495 
1496   if (!execution_unit_sp.get()) {
1497     err.SetErrorString(
1498         "can't run static initializers for a NULL execution unit");
1499     return err;
1500   }
1501 
1502   if (!exe_ctx.HasThreadScope()) {
1503     err.SetErrorString("can't run static initializers without a thread");
1504     return err;
1505   }
1506 
1507   std::vector<lldb::addr_t> static_initializers;
1508 
1509   execution_unit_sp->GetStaticInitializers(static_initializers);
1510 
1511   for (lldb::addr_t static_initializer : static_initializers) {
1512     EvaluateExpressionOptions options;
1513 
1514     lldb::ThreadPlanSP call_static_initializer(new ThreadPlanCallFunction(
1515         exe_ctx.GetThreadRef(), Address(static_initializer), CompilerType(),
1516         llvm::ArrayRef<lldb::addr_t>(), options));
1517 
1518     DiagnosticManager execution_errors;
1519     lldb::ExpressionResults results =
1520         exe_ctx.GetThreadRef().GetProcess()->RunThreadPlan(
1521             exe_ctx, call_static_initializer, options, execution_errors);
1522 
1523     if (results != lldb::eExpressionCompleted) {
1524       err.SetErrorStringWithFormat("couldn't run static initializer: %s",
1525                                    execution_errors.GetString().c_str());
1526       return err;
1527     }
1528   }
1529 
1530   return err;
1531 }
1532