1//===-- ClangASTImporter.h --------------------------------------*- 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#ifndef LLDB_SOURCE_PLUGINS_EXPRESSIONPARSER_CLANG_CLANGASTIMPORTER_H
10#define LLDB_SOURCE_PLUGINS_EXPRESSIONPARSER_CLANG_CLANGASTIMPORTER_H
11
12#include <map>
13#include <memory>
14#include <set>
15#include <vector>
16
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/ASTImporter.h"
19#include "clang/AST/CharUnits.h"
20#include "clang/AST/Decl.h"
21#include "clang/AST/DeclCXX.h"
22#include "clang/Basic/FileManager.h"
23#include "clang/Basic/FileSystemOptions.h"
24
25#include "lldb/Host/FileSystem.h"
26#include "lldb/Symbol/CompilerDeclContext.h"
27#include "lldb/Utility/LLDBAssert.h"
28#include "lldb/lldb-types.h"
29
30#include "Plugins/ExpressionParser/Clang/CxxModuleHandler.h"
31
32#include "llvm/ADT/DenseMap.h"
33
34namespace lldb_private {
35
36class ClangASTMetadata;
37class TypeSystemClang;
38
39/// Manages and observes all Clang AST node importing in LLDB.
40///
41/// The ClangASTImporter takes care of two things:
42///
43/// 1. Keeps track of all ASTImporter instances in LLDB.
44///
45/// Clang's ASTImporter takes care of importing types from one ASTContext to
46/// another. This class expands this concept by allowing copying from several
47/// ASTContext instances to several other ASTContext instances. Instead of
48/// constructing a new ASTImporter manually to copy over a type/decl, this class
49/// can be asked to do this. It will construct a ASTImporter for the caller (and
50/// will cache the ASTImporter instance for later use) and then perform the
51/// import.
52///
53/// This mainly prevents that a caller might construct several ASTImporter
54/// instances for the same source/target ASTContext combination. As the
55/// ASTImporter has an internal state that keeps track of already imported
56/// declarations and so on, using only one ASTImporter instance is more
57/// efficient and less error-prone than using multiple.
58///
59/// 2. Keeps track of from where declarations were imported (origin-tracking).
60/// The ASTImporter instances in this class usually only performa a minimal
61/// import, i.e., only a shallow copy is made that is filled out on demand
62/// when more information is requested later on. This requires record-keeping
63/// of where any shallow clone originally came from so that the right original
64/// declaration can be found and used as the source of any missing information.
65class ClangASTImporter {
66public:
67 struct LayoutInfo {
68 LayoutInfo() = default;
69 typedef llvm::DenseMap<const clang::CXXRecordDecl *, clang::CharUnits>
70 OffsetMap;
71
72 uint64_t bit_size = 0;
73 uint64_t alignment = 0;
74 llvm::DenseMap<const clang::FieldDecl *, uint64_t> field_offsets;
75 OffsetMap base_offsets;
76 OffsetMap vbase_offsets;
77 };
78
79 ClangASTImporter()
80 : m_file_manager(clang::FileSystemOptions(),
81 FileSystem::Instance().GetVirtualFileSystem()) {}
82
83 /// Copies the given type and the respective declarations to the destination
84 /// type system.
85 ///
86 /// This function does a shallow copy and requires that the target AST
87 /// has an ExternalASTSource which queries this ClangASTImporter instance
88 /// for any additional information that is maybe lacking in the shallow copy.
89 /// This also means that the type system of src_type can *not* be deleted
90 /// after this function has been called. If you need to delete the source
91 /// type system you either need to delete the destination type system first
92 /// or use \ref ClangASTImporter::DeportType.
93 ///
94 /// \see ClangASTImporter::DeportType
95 CompilerType CopyType(TypeSystemClang &dst, const CompilerType &src_type);
96
97 /// \see ClangASTImporter::CopyType
98 clang::Decl *CopyDecl(clang::ASTContext *dst_ctx, clang::Decl *decl);
99
100 /// Copies the given type and the respective declarations to the destination
101 /// type system.
102 ///
103 /// Unlike CopyType this function ensures that types/declarations which are
104 /// originally from the AST of src_type are fully copied over. The type
105 /// system of src_type can safely be deleted after calling this function.
106 /// \see ClangASTImporter::CopyType
107 CompilerType DeportType(TypeSystemClang &dst, const CompilerType &src_type);
108
109 /// Copies the given decl to the destination type system.
110 /// \see ClangASTImporter::DeportType
111 clang::Decl *DeportDecl(clang::ASTContext *dst_ctx, clang::Decl *decl);
112
113 /// Sets the layout for the given RecordDecl. The layout will later be
114 /// used by Clang's during code generation. Not calling this function for
115 /// a RecordDecl will cause that Clang's codegen tries to layout the
116 /// record by itself.
117 ///
118 /// \param decl The RecordDecl to set the layout for.
119 /// \param layout The layout for the record.
120 void SetRecordLayout(clang::RecordDecl *decl, const LayoutInfo &layout);
121
122 bool LayoutRecordType(
123 const clang::RecordDecl *record_decl, uint64_t &bit_size,
124 uint64_t &alignment,
125 llvm::DenseMap<const clang::FieldDecl *, uint64_t> &field_offsets,
126 llvm::DenseMap<const clang::CXXRecordDecl *, clang::CharUnits>
127 &base_offsets,
128 llvm::DenseMap<const clang::CXXRecordDecl *, clang::CharUnits>
129 &vbase_offsets);
130
131 /// If \ref record has a valid origin, this function copies that
132 /// origin's layout into this ClangASTImporter instance.
133 ///
134 /// \param[in] record The decl whose layout we're calculating.
135 /// \param[out] size Size of \ref record in bytes.
136 /// \param[out] alignment Alignment of \ref record in bytes.
137 /// \param[out] field_offsets Offsets of fields of \ref record.
138 /// \param[out] base_offsets Offsets of base classes of \ref record.
139 /// \param[out] vbase_offsets Offsets of virtual base classes of \ref record.
140 ///
141 /// \returns Returns 'false' if no valid origin was found for \ref record or
142 /// this function failed to import the layout from the origin. Otherwise,
143 /// returns 'true' and the offsets/size/alignment are valid for use.
144 bool importRecordLayoutFromOrigin(
145 const clang::RecordDecl *record, uint64_t &size, uint64_t &alignment,
146 llvm::DenseMap<const clang::FieldDecl *, uint64_t> &field_offsets,
147 llvm::DenseMap<const clang::CXXRecordDecl *, clang::CharUnits>
148 &base_offsets,
149 llvm::DenseMap<const clang::CXXRecordDecl *, clang::CharUnits>
150 &vbase_offsets);
151
152 /// Returns true iff the given type was copied from another TypeSystemClang
153 /// and the original type in this other TypeSystemClang might contain
154 /// additional information (e.g., the definition of a 'class' type) that could
155 /// be imported.
156 ///
157 /// \see ClangASTImporter::Import
158 bool CanImport(const CompilerType &type);
159
160 /// If the given type was copied from another TypeSystemClang then copy over
161 /// all missing information (e.g., the definition of a 'class' type).
162 ///
163 /// \return True iff an original type in another TypeSystemClang was found.
164 /// Note: Does *not* return false if an original type was found but
165 /// no information was imported over.
166 ///
167 /// \see ClangASTImporter::Import
168 bool Import(const CompilerType &type);
169
170 bool CompleteType(const CompilerType &compiler_type);
171
172 bool CompleteTagDecl(clang::TagDecl *decl);
173
174 bool CompleteTagDeclWithOrigin(clang::TagDecl *decl, clang::TagDecl *origin);
175
176 bool CompleteObjCInterfaceDecl(clang::ObjCInterfaceDecl *interface_decl);
177
178 bool CompleteAndFetchChildren(clang::QualType type);
179
180 bool RequireCompleteType(clang::QualType type);
181
182 /// Updates the internal origin-tracking information so that the given
183 /// 'original' decl is from now on used to import additional information
184 /// into the given decl.
185 ///
186 /// Usually the origin-tracking in the ClangASTImporter is automatically
187 /// updated when a declaration is imported, so the only valid reason to ever
188 /// call this is if there is a 'better' original decl and the target decl
189 /// is only a shallow clone that lacks any contents.
190 void SetDeclOrigin(const clang::Decl *decl, clang::Decl *original_decl);
191
192 ClangASTMetadata *GetDeclMetadata(const clang::Decl *decl);
193
194 //
195 // Namespace maps
196 //
197
198 typedef std::pair<lldb::ModuleSP, CompilerDeclContext> NamespaceMapItem;
199 typedef std::vector<NamespaceMapItem> NamespaceMap;
200 typedef std::shared_ptr<NamespaceMap> NamespaceMapSP;
201
202 void RegisterNamespaceMap(const clang::NamespaceDecl *decl,
203 NamespaceMapSP &namespace_map);
204
205 NamespaceMapSP GetNamespaceMap(const clang::NamespaceDecl *decl);
206
207 void BuildNamespaceMap(const clang::NamespaceDecl *decl);
208
209 //
210 // Completers for maps
211 //
212
213 class MapCompleter {
214 public:
215 virtual ~MapCompleter();
216
217 virtual void CompleteNamespaceMap(NamespaceMapSP &namespace_map,
218 ConstString name,
219 NamespaceMapSP &parent_map) const = 0;
220 };
221
222 void InstallMapCompleter(clang::ASTContext *dst_ctx,
223 MapCompleter &completer) {
224 ASTContextMetadataSP context_md;
225 ContextMetadataMap::iterator context_md_iter = m_metadata_map.find(Val: dst_ctx);
226
227 if (context_md_iter == m_metadata_map.end()) {
228 context_md = ASTContextMetadataSP(new ASTContextMetadata(dst_ctx));
229 m_metadata_map[dst_ctx] = context_md;
230 } else {
231 context_md = context_md_iter->second;
232 }
233
234 context_md->m_map_completer = &completer;
235 }
236
237 void ForgetDestination(clang::ASTContext *dst_ctx);
238 void ForgetSource(clang::ASTContext *dst_ctx, clang::ASTContext *src_ctx);
239
240 struct DeclOrigin {
241 DeclOrigin() = default;
242
243 DeclOrigin(clang::ASTContext *_ctx, clang::Decl *_decl)
244 : ctx(_ctx), decl(_decl) {
245 // The decl has to be in its associated ASTContext.
246 assert(_decl == nullptr || &_decl->getASTContext() == _ctx);
247 }
248
249 DeclOrigin(const DeclOrigin &rhs) {
250 ctx = rhs.ctx;
251 decl = rhs.decl;
252 }
253
254 void operator=(const DeclOrigin &rhs) {
255 ctx = rhs.ctx;
256 decl = rhs.decl;
257 }
258
259 bool Valid() const { return (ctx != nullptr || decl != nullptr); }
260
261 clang::ASTContext *ctx = nullptr;
262 clang::Decl *decl = nullptr;
263 };
264
265 /// Listener interface used by the ASTImporterDelegate to inform other code
266 /// about decls that have been imported the first time.
267 struct NewDeclListener {
268 virtual ~NewDeclListener() = default;
269 /// A decl has been imported for the first time.
270 virtual void NewDeclImported(clang::Decl *from, clang::Decl *to) = 0;
271 };
272
273 /// ASTImporter that intercepts and records the import process of the
274 /// underlying ASTImporter.
275 ///
276 /// This class updates the map from declarations to their original
277 /// declarations and can record declarations that have been imported in a
278 /// certain interval.
279 ///
280 /// When intercepting a declaration import, the ASTImporterDelegate uses the
281 /// CxxModuleHandler to replace any missing or malformed declarations with
282 /// their counterpart from a C++ module.
283 struct ASTImporterDelegate : public clang::ASTImporter {
284 ASTImporterDelegate(ClangASTImporter &main, clang::ASTContext *target_ctx,
285 clang::ASTContext *source_ctx)
286 : clang::ASTImporter(*target_ctx, main.m_file_manager, *source_ctx,
287 main.m_file_manager, true /*minimal*/),
288 m_main(main), m_source_ctx(source_ctx) {
289 // Target and source ASTContext shouldn't be identical. Importing AST
290 // nodes within the same AST doesn't make any sense as the whole idea
291 // is to import them to a different AST.
292 lldbassert(target_ctx != source_ctx && "Can't import into itself");
293 // This is always doing a minimal import of any declarations. This means
294 // that there has to be an ExternalASTSource in the target ASTContext
295 // (that should implement the callbacks that complete any declarations
296 // on demand). Without an ExternalASTSource, this ASTImporter will just
297 // do a minimal import and the imported declarations won't be completed.
298 assert(target_ctx->getExternalSource() && "Missing ExternalSource");
299 setODRHandling(clang::ASTImporter::ODRHandlingType::Liberal);
300 }
301
302 /// Scope guard that attaches a CxxModuleHandler to an ASTImporterDelegate
303 /// and deattaches it at the end of the scope. Supports being used multiple
304 /// times on the same ASTImporterDelegate instance in nested scopes.
305 class CxxModuleScope {
306 /// The handler we attach to the ASTImporterDelegate.
307 CxxModuleHandler m_handler;
308 /// The ASTImporterDelegate we are supposed to attach the handler to.
309 ASTImporterDelegate &m_delegate;
310 /// True iff we attached the handler to the ASTImporterDelegate.
311 bool m_valid = false;
312
313 public:
314 CxxModuleScope(ASTImporterDelegate &delegate, clang::ASTContext *dst_ctx)
315 : m_delegate(delegate) {
316 // If the delegate doesn't have a CxxModuleHandler yet, create one
317 // and attach it.
318 if (!delegate.m_std_handler) {
319 m_handler = CxxModuleHandler(delegate, dst_ctx);
320 m_valid = true;
321 delegate.m_std_handler = &m_handler;
322 }
323 }
324 ~CxxModuleScope() {
325 if (m_valid) {
326 // Make sure no one messed with the handler we placed.
327 assert(m_delegate.m_std_handler == &m_handler);
328 m_delegate.m_std_handler = nullptr;
329 }
330 }
331 };
332
333 void ImportDefinitionTo(clang::Decl *to, clang::Decl *from);
334
335 void Imported(clang::Decl *from, clang::Decl *to) override;
336
337 clang::Decl *GetOriginalDecl(clang::Decl *To) override;
338
339 void SetImportListener(NewDeclListener *listener) {
340 assert(m_new_decl_listener == nullptr && "Already attached a listener?");
341 m_new_decl_listener = listener;
342 }
343 void RemoveImportListener() { m_new_decl_listener = nullptr; }
344
345 protected:
346 llvm::Expected<clang::Decl *> ImportImpl(clang::Decl *From) override;
347
348 private:
349 /// Decls we should ignore when mapping decls back to their original
350 /// ASTContext. Used by the CxxModuleHandler to mark declarations that
351 /// were created from the 'std' C++ module to prevent that the Importer
352 /// tries to sync them with the broken equivalent in the debug info AST.
353 llvm::SmallPtrSet<clang::Decl *, 16> m_decls_to_ignore;
354 ClangASTImporter &m_main;
355 clang::ASTContext *m_source_ctx;
356 CxxModuleHandler *m_std_handler = nullptr;
357 /// The currently attached listener.
358 NewDeclListener *m_new_decl_listener = nullptr;
359 };
360
361 typedef std::shared_ptr<ASTImporterDelegate> ImporterDelegateSP;
362 typedef llvm::DenseMap<clang::ASTContext *, ImporterDelegateSP> DelegateMap;
363 typedef llvm::DenseMap<const clang::NamespaceDecl *, NamespaceMapSP>
364 NamespaceMetaMap;
365
366 class ASTContextMetadata {
367 typedef llvm::DenseMap<const clang::Decl *, DeclOrigin> OriginMap;
368
369 public:
370 ASTContextMetadata(clang::ASTContext *dst_ctx) : m_dst_ctx(dst_ctx) {}
371
372 clang::ASTContext *m_dst_ctx;
373 DelegateMap m_delegates;
374
375 NamespaceMetaMap m_namespace_maps;
376 MapCompleter *m_map_completer = nullptr;
377
378 /// Sets the DeclOrigin for the given Decl and overwrites any existing
379 /// DeclOrigin.
380 void setOrigin(const clang::Decl *decl, DeclOrigin origin) {
381 // Setting the origin of any decl to itself (or to a different decl
382 // in the same ASTContext) doesn't make any sense. It will also cause
383 // ASTImporterDelegate::ImportImpl to infinite recurse when trying to find
384 // the 'original' Decl when importing code.
385 assert(&decl->getASTContext() != origin.ctx &&
386 "Trying to set decl origin to its own ASTContext?");
387 assert(decl != origin.decl && "Trying to set decl origin to itself?");
388 m_origins[decl] = origin;
389 }
390
391 /// Removes any tracked DeclOrigin for the given decl.
392 void removeOrigin(const clang::Decl *decl) { m_origins.erase(Val: decl); }
393
394 /// Remove all DeclOrigin entries that point to the given ASTContext.
395 /// Useful when an ASTContext is about to be deleted and all the dangling
396 /// pointers to it need to be removed.
397 void removeOriginsWithContext(clang::ASTContext *ctx) {
398 for (OriginMap::iterator iter = m_origins.begin();
399 iter != m_origins.end();) {
400 if (iter->second.ctx == ctx)
401 m_origins.erase(I: iter++);
402 else
403 ++iter;
404 }
405 }
406
407 /// Returns the DeclOrigin for the given Decl or an invalid DeclOrigin
408 /// instance if there no known DeclOrigin for the given Decl.
409 DeclOrigin getOrigin(const clang::Decl *decl) const {
410 auto iter = m_origins.find(Val: decl);
411 if (iter == m_origins.end())
412 return DeclOrigin();
413 return iter->second;
414 }
415
416 /// Returns true there is a known DeclOrigin for the given Decl.
417 bool hasOrigin(const clang::Decl *decl) const {
418 return getOrigin(decl).Valid();
419 }
420
421 private:
422 /// Maps declarations to the ASTContext/Decl from which they were imported
423 /// from. If a declaration is from an ASTContext which has been deleted
424 /// since the declaration was imported or the declaration wasn't created by
425 /// the ASTImporter, then it doesn't have a DeclOrigin and will not be
426 /// tracked here.
427 OriginMap m_origins;
428 };
429
430 typedef std::shared_ptr<ASTContextMetadata> ASTContextMetadataSP;
431 typedef llvm::DenseMap<const clang::ASTContext *, ASTContextMetadataSP>
432 ContextMetadataMap;
433
434 ContextMetadataMap m_metadata_map;
435
436 ASTContextMetadataSP GetContextMetadata(clang::ASTContext *dst_ctx) {
437 ContextMetadataMap::iterator context_md_iter = m_metadata_map.find(Val: dst_ctx);
438
439 if (context_md_iter == m_metadata_map.end()) {
440 ASTContextMetadataSP context_md =
441 ASTContextMetadataSP(new ASTContextMetadata(dst_ctx));
442 m_metadata_map[dst_ctx] = context_md;
443 return context_md;
444 }
445 return context_md_iter->second;
446 }
447
448 ASTContextMetadataSP MaybeGetContextMetadata(clang::ASTContext *dst_ctx) {
449 ContextMetadataMap::iterator context_md_iter = m_metadata_map.find(Val: dst_ctx);
450
451 if (context_md_iter != m_metadata_map.end())
452 return context_md_iter->second;
453 return ASTContextMetadataSP();
454 }
455
456 ImporterDelegateSP GetDelegate(clang::ASTContext *dst_ctx,
457 clang::ASTContext *src_ctx) {
458 ASTContextMetadataSP context_md = GetContextMetadata(dst_ctx);
459
460 DelegateMap &delegates = context_md->m_delegates;
461 DelegateMap::iterator delegate_iter = delegates.find(Val: src_ctx);
462
463 if (delegate_iter == delegates.end()) {
464 ImporterDelegateSP delegate =
465 ImporterDelegateSP(new ASTImporterDelegate(*this, dst_ctx, src_ctx));
466 delegates[src_ctx] = delegate;
467 return delegate;
468 }
469 return delegate_iter->second;
470 }
471
472 DeclOrigin GetDeclOrigin(const clang::Decl *decl);
473
474 clang::FileManager m_file_manager;
475 typedef llvm::DenseMap<const clang::RecordDecl *, LayoutInfo>
476 RecordDeclToLayoutMap;
477
478 RecordDeclToLayoutMap m_record_decl_to_layout_map;
479};
480
481template <class D> class TaggedASTDecl {
482public:
483 TaggedASTDecl() : decl(nullptr) {}
484 TaggedASTDecl(D *_decl) : decl(_decl) {}
485 bool IsValid() const { return (decl != nullptr); }
486 bool IsInvalid() const { return !IsValid(); }
487 D *operator->() const { return decl; }
488 D *decl;
489};
490
491template <class D2, template <class D> class TD, class D1>
492TD<D2> DynCast(TD<D1> source) {
493 return TD<D2>(llvm::dyn_cast<D2>(source.decl));
494}
495
496template <class D = clang::Decl> class DeclFromParser;
497template <class D = clang::Decl> class DeclFromUser;
498
499template <class D> class DeclFromParser : public TaggedASTDecl<D> {
500public:
501 DeclFromParser() : TaggedASTDecl<D>() {}
502 DeclFromParser(D *_decl) : TaggedASTDecl<D>(_decl) {}
503
504 DeclFromUser<D> GetOrigin(ClangASTImporter &importer);
505};
506
507template <class D> class DeclFromUser : public TaggedASTDecl<D> {
508public:
509 DeclFromUser() : TaggedASTDecl<D>() {}
510 DeclFromUser(D *_decl) : TaggedASTDecl<D>(_decl) {}
511
512 DeclFromParser<D> Import(clang::ASTContext *dest_ctx,
513 ClangASTImporter &importer);
514};
515
516template <class D>
517DeclFromUser<D> DeclFromParser<D>::GetOrigin(ClangASTImporter &importer) {
518 ClangASTImporter::DeclOrigin origin = importer.GetDeclOrigin(decl: this->decl);
519 if (!origin.Valid())
520 return DeclFromUser<D>();
521 return DeclFromUser<D>(llvm::dyn_cast<D>(origin.decl));
522}
523
524template <class D>
525DeclFromParser<D> DeclFromUser<D>::Import(clang::ASTContext *dest_ctx,
526 ClangASTImporter &importer) {
527 DeclFromParser<> parser_generic_decl(importer.CopyDecl(dst_ctx: dest_ctx, decl: this->decl));
528 if (parser_generic_decl.IsInvalid())
529 return DeclFromParser<D>();
530 return DeclFromParser<D>(llvm::dyn_cast<D>(parser_generic_decl.decl));
531}
532
533} // namespace lldb_private
534
535#endif // LLDB_SOURCE_PLUGINS_EXPRESSIONPARSER_CLANG_CLANGASTIMPORTER_H
536

source code of lldb/source/Plugins/ExpressionParser/Clang/ClangASTImporter.h