1//===------ CodeCompletion.cpp - Code Completion for ClangRepl -------===//
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// This file implements the classes which performs code completion at the REPL.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/Interpreter/CodeCompletion.h"
14#include "clang/AST/ASTImporter.h"
15#include "clang/AST/DeclLookups.h"
16#include "clang/AST/DeclarationName.h"
17#include "clang/AST/ExternalASTSource.h"
18#include "clang/Basic/IdentifierTable.h"
19#include "clang/Frontend/ASTUnit.h"
20#include "clang/Frontend/CompilerInstance.h"
21#include "clang/Frontend/FrontendActions.h"
22#include "clang/Interpreter/Interpreter.h"
23#include "clang/Lex/PreprocessorOptions.h"
24#include "clang/Sema/CodeCompleteConsumer.h"
25#include "clang/Sema/CodeCompleteOptions.h"
26#include "clang/Sema/Sema.h"
27#include "llvm/Support/Debug.h"
28#define DEBUG_TYPE "REPLCC"
29
30namespace clang {
31
32const std::string CodeCompletionFileName = "input_line_[Completion]";
33
34clang::CodeCompleteOptions getClangCompleteOpts() {
35 clang::CodeCompleteOptions Opts;
36 Opts.IncludeCodePatterns = true;
37 Opts.IncludeMacros = true;
38 Opts.IncludeGlobals = true;
39 Opts.IncludeBriefComments = true;
40 return Opts;
41}
42
43class ReplCompletionConsumer : public CodeCompleteConsumer {
44public:
45 ReplCompletionConsumer(std::vector<std::string> &Results,
46 ReplCodeCompleter &CC)
47 : CodeCompleteConsumer(getClangCompleteOpts()),
48 CCAllocator(std::make_shared<GlobalCodeCompletionAllocator>()),
49 CCTUInfo(CCAllocator), Results(Results), CC(CC) {}
50
51 // The entry of handling code completion. When the function is called, we
52 // create a `Context`-based handler (see classes defined below) to handle each
53 // completion result.
54 void ProcessCodeCompleteResults(class Sema &S, CodeCompletionContext Context,
55 CodeCompletionResult *InResults,
56 unsigned NumResults) final;
57
58 CodeCompletionAllocator &getAllocator() override { return *CCAllocator; }
59
60 CodeCompletionTUInfo &getCodeCompletionTUInfo() override { return CCTUInfo; }
61
62private:
63 std::shared_ptr<GlobalCodeCompletionAllocator> CCAllocator;
64 CodeCompletionTUInfo CCTUInfo;
65 std::vector<std::string> &Results;
66 ReplCodeCompleter &CC;
67};
68
69/// The class CompletionContextHandler contains four interfaces, each of
70/// which handles one type of completion result.
71/// Its derived classes are used to create concrete handlers based on
72/// \c CodeCompletionContext.
73class CompletionContextHandler {
74protected:
75 CodeCompletionContext CCC;
76 std::vector<std::string> &Results;
77
78private:
79 Sema &S;
80
81public:
82 CompletionContextHandler(Sema &S, CodeCompletionContext CCC,
83 std::vector<std::string> &Results)
84 : CCC(CCC), Results(Results), S(S) {}
85
86 virtual ~CompletionContextHandler() = default;
87 /// Converts a Declaration completion result to a completion string, and then
88 /// stores it in Results.
89 virtual void handleDeclaration(const CodeCompletionResult &Result) {
90 auto PreferredType = CCC.getPreferredType();
91 if (PreferredType.isNull()) {
92 Results.push_back(x: Result.Declaration->getName().str());
93 return;
94 }
95
96 if (auto *VD = dyn_cast<VarDecl>(Val: Result.Declaration)) {
97 auto ArgumentType = VD->getType();
98 if (PreferredType->isReferenceType()) {
99 QualType RT = PreferredType->castAs<ReferenceType>()->getPointeeType();
100 Sema::ReferenceConversions RefConv;
101 Sema::ReferenceCompareResult RefRelationship =
102 S.CompareReferenceRelationship(Loc: SourceLocation(), T1: RT, T2: ArgumentType,
103 Conv: &RefConv);
104 switch (RefRelationship) {
105 case Sema::Ref_Compatible:
106 case Sema::Ref_Related:
107 Results.push_back(VD->getName().str());
108 break;
109 case Sema::Ref_Incompatible:
110 break;
111 }
112 } else if (S.Context.hasSameType(ArgumentType, PreferredType)) {
113 Results.push_back(VD->getName().str());
114 }
115 }
116 }
117
118 /// Converts a Keyword completion result to a completion string, and then
119 /// stores it in Results.
120 virtual void handleKeyword(const CodeCompletionResult &Result) {
121 auto Prefix = S.getPreprocessor().getCodeCompletionFilter();
122 // Add keyword to the completion results only if we are in a type-aware
123 // situation.
124 if (!CCC.getBaseType().isNull() || !CCC.getPreferredType().isNull())
125 return;
126 if (StringRef(Result.Keyword).starts_with(Prefix))
127 Results.push_back(x: Result.Keyword);
128 }
129
130 /// Converts a Pattern completion result to a completion string, and then
131 /// stores it in Results.
132 virtual void handlePattern(const CodeCompletionResult &Result) {}
133
134 /// Converts a Macro completion result to a completion string, and then stores
135 /// it in Results.
136 virtual void handleMacro(const CodeCompletionResult &Result) {}
137};
138
139class DotMemberAccessHandler : public CompletionContextHandler {
140public:
141 DotMemberAccessHandler(Sema &S, CodeCompletionContext CCC,
142 std::vector<std::string> &Results)
143 : CompletionContextHandler(S, CCC, Results) {}
144 void handleDeclaration(const CodeCompletionResult &Result) override {
145 auto *ID = Result.Declaration->getIdentifier();
146 if (!ID)
147 return;
148 if (!isa<CXXMethodDecl>(Val: Result.Declaration))
149 return;
150 const auto *Fun = cast<CXXMethodDecl>(Val: Result.Declaration);
151 if (Fun->getParent()->getCanonicalDecl() ==
152 CCC.getBaseType()->getAsCXXRecordDecl()->getCanonicalDecl()) {
153 LLVM_DEBUG(llvm::dbgs() << "[In HandleCodeCompleteDOT] Name : "
154 << ID->getName() << "\n");
155 Results.push_back(x: ID->getName().str());
156 }
157 }
158
159 void handleKeyword(const CodeCompletionResult &Result) override {}
160};
161
162void ReplCompletionConsumer::ProcessCodeCompleteResults(
163 class Sema &S, CodeCompletionContext Context,
164 CodeCompletionResult *InResults, unsigned NumResults) {
165
166 auto Prefix = S.getPreprocessor().getCodeCompletionFilter();
167 CC.Prefix = Prefix;
168
169 std::unique_ptr<CompletionContextHandler> CCH;
170
171 // initialize fine-grained code completion handler based on the code
172 // completion context.
173 switch (Context.getKind()) {
174 case CodeCompletionContext::CCC_DotMemberAccess:
175 CCH.reset(new DotMemberAccessHandler(S, Context, this->Results));
176 break;
177 default:
178 CCH.reset(p: new CompletionContextHandler(S, Context, this->Results));
179 };
180
181 for (unsigned I = 0; I < NumResults; I++) {
182 auto &Result = InResults[I];
183 switch (Result.Kind) {
184 case CodeCompletionResult::RK_Declaration:
185 if (Result.Hidden) {
186 break;
187 }
188 if (!Result.Declaration->getDeclName().isIdentifier() ||
189 !Result.Declaration->getName().starts_with(Prefix)) {
190 break;
191 }
192 CCH->handleDeclaration(Result);
193 break;
194 case CodeCompletionResult::RK_Keyword:
195 CCH->handleKeyword(Result);
196 break;
197 case CodeCompletionResult::RK_Macro:
198 CCH->handleMacro(Result);
199 break;
200 case CodeCompletionResult::RK_Pattern:
201 CCH->handlePattern(Result);
202 break;
203 }
204 }
205
206 std::sort(first: Results.begin(), last: Results.end());
207}
208
209class IncrementalSyntaxOnlyAction : public SyntaxOnlyAction {
210 const CompilerInstance *ParentCI;
211
212public:
213 IncrementalSyntaxOnlyAction(const CompilerInstance *ParentCI)
214 : ParentCI(ParentCI) {}
215
216protected:
217 void ExecuteAction() override;
218};
219
220class ExternalSource : public clang::ExternalASTSource {
221 TranslationUnitDecl *ChildTUDeclCtxt;
222 ASTContext &ParentASTCtxt;
223 TranslationUnitDecl *ParentTUDeclCtxt;
224
225 std::unique_ptr<ASTImporter> Importer;
226
227public:
228 ExternalSource(ASTContext &ChildASTCtxt, FileManager &ChildFM,
229 ASTContext &ParentASTCtxt, FileManager &ParentFM);
230 bool FindExternalVisibleDeclsByName(const DeclContext *DC,
231 DeclarationName Name) override;
232 void
233 completeVisibleDeclsMap(const clang::DeclContext *childDeclContext) override;
234};
235
236// This method is intended to set up `ExternalASTSource` to the running
237// compiler instance before the super `ExecuteAction` triggers parsing
238void IncrementalSyntaxOnlyAction::ExecuteAction() {
239 CompilerInstance &CI = getCompilerInstance();
240 ExternalSource *myExternalSource =
241 new ExternalSource(CI.getASTContext(), CI.getFileManager(),
242 ParentCI->getASTContext(), ParentCI->getFileManager());
243 llvm::IntrusiveRefCntPtr<clang::ExternalASTSource> astContextExternalSource(
244 myExternalSource);
245 CI.getASTContext().setExternalSource(astContextExternalSource);
246 CI.getASTContext().getTranslationUnitDecl()->setHasExternalVisibleStorage(
247 true);
248
249 // Load all external decls into current context. Under the hood, it calls
250 // ExternalSource::completeVisibleDeclsMap, which make all decls on the redecl
251 // chain visible.
252 //
253 // This is crucial to code completion on dot members, since a bound variable
254 // before "." would be otherwise treated out-of-scope.
255 //
256 // clang-repl> Foo f1;
257 // clang-repl> f1.<tab>
258 CI.getASTContext().getTranslationUnitDecl()->lookups();
259 SyntaxOnlyAction::ExecuteAction();
260}
261
262ExternalSource::ExternalSource(ASTContext &ChildASTCtxt, FileManager &ChildFM,
263 ASTContext &ParentASTCtxt, FileManager &ParentFM)
264 : ChildTUDeclCtxt(ChildASTCtxt.getTranslationUnitDecl()),
265 ParentASTCtxt(ParentASTCtxt),
266 ParentTUDeclCtxt(ParentASTCtxt.getTranslationUnitDecl()) {
267 ASTImporter *importer =
268 new ASTImporter(ChildASTCtxt, ChildFM, ParentASTCtxt, ParentFM,
269 /*MinimalImport : ON*/ true);
270 Importer.reset(p: importer);
271}
272
273bool ExternalSource::FindExternalVisibleDeclsByName(const DeclContext *DC,
274 DeclarationName Name) {
275
276 IdentifierTable &ParentIdTable = ParentASTCtxt.Idents;
277
278 auto ParentDeclName =
279 DeclarationName(&(ParentIdTable.get(Name: Name.getAsString())));
280
281 DeclContext::lookup_result lookup_result =
282 ParentTUDeclCtxt->lookup(ParentDeclName);
283
284 if (!lookup_result.empty()) {
285 return true;
286 }
287 return false;
288}
289
290void ExternalSource::completeVisibleDeclsMap(
291 const DeclContext *ChildDeclContext) {
292 assert(ChildDeclContext && ChildDeclContext == ChildTUDeclCtxt &&
293 "No child decl context!");
294
295 if (!ChildDeclContext->hasExternalVisibleStorage())
296 return;
297
298 for (auto *DeclCtxt = ParentTUDeclCtxt; DeclCtxt != nullptr;
299 DeclCtxt = DeclCtxt->getPreviousDecl()) {
300 for (auto &IDeclContext : DeclCtxt->decls()) {
301 if (!llvm::isa<NamedDecl>(IDeclContext))
302 continue;
303
304 NamedDecl *Decl = llvm::cast<NamedDecl>(IDeclContext);
305
306 auto DeclOrErr = Importer->Import(Decl);
307 if (!DeclOrErr) {
308 // if an error happens, it usually means the decl has already been
309 // imported or the decl is a result of a failed import. But in our
310 // case, every import is fresh each time code completion is
311 // triggered. So Import usually doesn't fail. If it does, it just means
312 // the related decl can't be used in code completion and we can safely
313 // drop it.
314 llvm::consumeError(DeclOrErr.takeError());
315 continue;
316 }
317
318 if (!llvm::isa<NamedDecl>(*DeclOrErr))
319 continue;
320
321 NamedDecl *importedNamedDecl = llvm::cast<NamedDecl>(*DeclOrErr);
322
323 SetExternalVisibleDeclsForName(ChildDeclContext,
324 importedNamedDecl->getDeclName(),
325 importedNamedDecl);
326
327 if (!llvm::isa<CXXRecordDecl>(importedNamedDecl))
328 continue;
329
330 auto *Record = llvm::cast<CXXRecordDecl>(importedNamedDecl);
331
332 if (auto Err = Importer->ImportDefinition(Decl)) {
333 // the same as above
334 consumeError(std::move(Err));
335 continue;
336 }
337
338 Record->setHasLoadedFieldsFromExternalStorage(true);
339 LLVM_DEBUG(llvm::dbgs()
340 << "\nCXXRecrod : " << Record->getName() << " size(methods): "
341 << std::distance(Record->method_begin(), Record->method_end())
342 << " has def?: " << Record->hasDefinition()
343 << " # (methods): "
344 << std::distance(Record->getDefinition()->method_begin(),
345 Record->getDefinition()->method_end())
346 << "\n");
347 for (auto *Meth : Record->methods())
348 SetExternalVisibleDeclsForName(ChildDeclContext, Meth->getDeclName(),
349 Meth);
350 }
351 ChildDeclContext->setHasExternalLexicalStorage(false);
352 }
353}
354
355void ReplCodeCompleter::codeComplete(CompilerInstance *InterpCI,
356 llvm::StringRef Content, unsigned Line,
357 unsigned Col,
358 const CompilerInstance *ParentCI,
359 std::vector<std::string> &CCResults) {
360 auto DiagOpts = DiagnosticOptions();
361 auto consumer = ReplCompletionConsumer(CCResults, *this);
362
363 auto diag = InterpCI->getDiagnosticsPtr();
364 std::unique_ptr<ASTUnit> AU(ASTUnit::LoadFromCompilerInvocationAction(
365 CI: InterpCI->getInvocationPtr(), PCHContainerOps: std::make_shared<PCHContainerOperations>(),
366 Diags: diag));
367 llvm::SmallVector<clang::StoredDiagnostic, 8> sd = {};
368 llvm::SmallVector<const llvm::MemoryBuffer *, 1> tb = {};
369 InterpCI->getFrontendOpts().Inputs[0] = FrontendInputFile(
370 CodeCompletionFileName, Language::CXX, InputKind::Source);
371 auto Act = std::unique_ptr<IncrementalSyntaxOnlyAction>(
372 new IncrementalSyntaxOnlyAction(ParentCI));
373 std::unique_ptr<llvm::MemoryBuffer> MB =
374 llvm::MemoryBuffer::getMemBufferCopy(InputData: Content, BufferName: CodeCompletionFileName);
375 llvm::SmallVector<ASTUnit::RemappedFile, 4> RemappedFiles;
376
377 RemappedFiles.push_back(Elt: std::make_pair(x: CodeCompletionFileName, y: MB.get()));
378 // we don't want the AU destructor to release the memory buffer that MB
379 // owns twice, because MB handles its resource on its own.
380 AU->setOwnsRemappedFileBuffers(false);
381 AU->CodeComplete(File: CodeCompletionFileName, Line: 1, Column: Col, RemappedFiles, IncludeMacros: false, IncludeCodePatterns: false,
382 IncludeBriefComments: false, Consumer&: consumer,
383 PCHContainerOps: std::make_shared<clang::PCHContainerOperations>(), Diag&: *diag,
384 LangOpts&: InterpCI->getLangOpts(), SourceMgr&: InterpCI->getSourceManager(),
385 FileMgr&: InterpCI->getFileManager(), StoredDiagnostics&: sd, OwnedBuffers&: tb, Act: std::move(Act));
386}
387
388} // namespace clang
389

source code of clang/lib/Interpreter/CodeCompletion.cpp