1 //===--- CodeCompleteConsumer.cpp - Code Completion Interface ---*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file implements the CodeCompleteConsumer class.
11 //
12 //===----------------------------------------------------------------------===//
13 #include "clang/Sema/CodeCompleteConsumer.h"
14 #include "clang/Sema/Scope.h"
15 #include "clang/Sema/Sema.h"
16 #include "clang/AST/DeclCXX.h"
17 #include "clang/AST/DeclObjC.h"
18 #include "clang/AST/DeclTemplate.h"
19 #include "clang/Lex/Preprocessor.h"
20 #include "clang-c/Index.h"
21 #include "llvm/ADT/SmallString.h"
22 #include "llvm/ADT/STLExtras.h"
23 #include "llvm/ADT/Twine.h"
24 #include "llvm/Support/raw_ostream.h"
25 #include <algorithm>
26 #include <cstring>
27 #include <functional>
28 
29 using namespace clang;
30 
31 //===----------------------------------------------------------------------===//
32 // Code completion context implementation
33 //===----------------------------------------------------------------------===//
34 
35 bool CodeCompletionContext::wantConstructorResults() const {
36   switch (Kind) {
37   case CCC_Recovery:
38   case CCC_Statement:
39   case CCC_Expression:
40   case CCC_ObjCMessageReceiver:
41   case CCC_ParenthesizedExpression:
42     return true;
43 
44   case CCC_TopLevel:
45   case CCC_ObjCInterface:
46   case CCC_ObjCImplementation:
47   case CCC_ObjCIvarList:
48   case CCC_ClassStructUnion:
49   case CCC_DotMemberAccess:
50   case CCC_ArrowMemberAccess:
51   case CCC_ObjCPropertyAccess:
52   case CCC_EnumTag:
53   case CCC_UnionTag:
54   case CCC_ClassOrStructTag:
55   case CCC_ObjCProtocolName:
56   case CCC_Namespace:
57   case CCC_Type:
58   case CCC_Name:
59   case CCC_PotentiallyQualifiedName:
60   case CCC_MacroName:
61   case CCC_MacroNameUse:
62   case CCC_PreprocessorExpression:
63   case CCC_PreprocessorDirective:
64   case CCC_NaturalLanguage:
65   case CCC_SelectorName:
66   case CCC_TypeQualifiers:
67   case CCC_Other:
68   case CCC_OtherWithMacros:
69   case CCC_ObjCInstanceMessage:
70   case CCC_ObjCClassMessage:
71   case CCC_ObjCInterfaceName:
72   case CCC_ObjCCategoryName:
73     return false;
74   }
75 
76   llvm_unreachable("Invalid CodeCompletionContext::Kind!");
77 }
78 
79 //===----------------------------------------------------------------------===//
80 // Code completion string implementation
81 //===----------------------------------------------------------------------===//
82 CodeCompletionString::Chunk::Chunk(ChunkKind Kind, const char *Text)
83   : Kind(Kind), Text("")
84 {
85   switch (Kind) {
86   case CK_TypedText:
87   case CK_Text:
88   case CK_Placeholder:
89   case CK_Informative:
90   case CK_ResultType:
91   case CK_CurrentParameter:
92     this->Text = Text;
93     break;
94 
95   case CK_Optional:
96     llvm_unreachable("Optional strings cannot be created from text");
97 
98   case CK_LeftParen:
99     this->Text = "(";
100     break;
101 
102   case CK_RightParen:
103     this->Text = ")";
104     break;
105 
106   case CK_LeftBracket:
107     this->Text = "[";
108     break;
109 
110   case CK_RightBracket:
111     this->Text = "]";
112     break;
113 
114   case CK_LeftBrace:
115     this->Text = "{";
116     break;
117 
118   case CK_RightBrace:
119     this->Text = "}";
120     break;
121 
122   case CK_LeftAngle:
123     this->Text = "<";
124     break;
125 
126   case CK_RightAngle:
127     this->Text = ">";
128     break;
129 
130   case CK_Comma:
131     this->Text = ", ";
132     break;
133 
134   case CK_Colon:
135     this->Text = ":";
136     break;
137 
138   case CK_SemiColon:
139     this->Text = ";";
140     break;
141 
142   case CK_Equal:
143     this->Text = " = ";
144     break;
145 
146   case CK_HorizontalSpace:
147     this->Text = " ";
148     break;
149 
150   case CK_VerticalSpace:
151     this->Text = "\n";
152     break;
153   }
154 }
155 
156 CodeCompletionString::Chunk
157 CodeCompletionString::Chunk::CreateText(const char *Text) {
158   return Chunk(CK_Text, Text);
159 }
160 
161 CodeCompletionString::Chunk
162 CodeCompletionString::Chunk::CreateOptional(CodeCompletionString *Optional) {
163   Chunk Result;
164   Result.Kind = CK_Optional;
165   Result.Optional = Optional;
166   return Result;
167 }
168 
169 CodeCompletionString::Chunk
170 CodeCompletionString::Chunk::CreatePlaceholder(const char *Placeholder) {
171   return Chunk(CK_Placeholder, Placeholder);
172 }
173 
174 CodeCompletionString::Chunk
175 CodeCompletionString::Chunk::CreateInformative(const char *Informative) {
176   return Chunk(CK_Informative, Informative);
177 }
178 
179 CodeCompletionString::Chunk
180 CodeCompletionString::Chunk::CreateResultType(const char *ResultType) {
181   return Chunk(CK_ResultType, ResultType);
182 }
183 
184 CodeCompletionString::Chunk
185 CodeCompletionString::Chunk::CreateCurrentParameter(
186                                                 const char *CurrentParameter) {
187   return Chunk(CK_CurrentParameter, CurrentParameter);
188 }
189 
190 CodeCompletionString::CodeCompletionString(const Chunk *Chunks,
191                                            unsigned NumChunks,
192                                            unsigned Priority,
193                                            CXAvailabilityKind Availability,
194                                            const char **Annotations,
195                                            unsigned NumAnnotations,
196                                            CXCursorKind ParentKind,
197                                            StringRef ParentName)
198   : NumChunks(NumChunks), NumAnnotations(NumAnnotations),
199     Priority(Priority), Availability(Availability), ParentKind(ParentKind),
200     ParentName(ParentName)
201 {
202   assert(NumChunks <= 0xffff);
203   assert(NumAnnotations <= 0xffff);
204 
205   Chunk *StoredChunks = reinterpret_cast<Chunk *>(this + 1);
206   for (unsigned I = 0; I != NumChunks; ++I)
207     StoredChunks[I] = Chunks[I];
208 
209   const char **StoredAnnotations = reinterpret_cast<const char **>(StoredChunks + NumChunks);
210   for (unsigned I = 0; I != NumAnnotations; ++I)
211     StoredAnnotations[I] = Annotations[I];
212 }
213 
214 unsigned CodeCompletionString::getAnnotationCount() const {
215   return NumAnnotations;
216 }
217 
218 const char *CodeCompletionString::getAnnotation(unsigned AnnotationNr) const {
219   if (AnnotationNr < NumAnnotations)
220     return reinterpret_cast<const char * const*>(end())[AnnotationNr];
221   else
222     return 0;
223 }
224 
225 
226 std::string CodeCompletionString::getAsString() const {
227   std::string Result;
228   llvm::raw_string_ostream OS(Result);
229 
230   for (iterator C = begin(), CEnd = end(); C != CEnd; ++C) {
231     switch (C->Kind) {
232     case CK_Optional: OS << "{#" << C->Optional->getAsString() << "#}"; break;
233     case CK_Placeholder: OS << "<#" << C->Text << "#>"; break;
234 
235     case CK_Informative:
236     case CK_ResultType:
237       OS << "[#" << C->Text << "#]";
238       break;
239 
240     case CK_CurrentParameter: OS << "<#" << C->Text << "#>"; break;
241     default: OS << C->Text; break;
242     }
243   }
244   return OS.str();
245 }
246 
247 const char *CodeCompletionString::getTypedText() const {
248   for (iterator C = begin(), CEnd = end(); C != CEnd; ++C)
249     if (C->Kind == CK_TypedText)
250       return C->Text;
251 
252   return 0;
253 }
254 
255 const char *CodeCompletionAllocator::CopyString(StringRef String) {
256   char *Mem = (char *)Allocate(String.size() + 1, 1);
257   std::copy(String.begin(), String.end(), Mem);
258   Mem[String.size()] = 0;
259   return Mem;
260 }
261 
262 const char *CodeCompletionAllocator::CopyString(Twine String) {
263   // FIXME: It would be more efficient to teach Twine to tell us its size and
264   // then add a routine there to fill in an allocated char* with the contents
265   // of the string.
266   SmallString<128> Data;
267   return CopyString(String.toStringRef(Data));
268 }
269 
270 CodeCompletionString *CodeCompletionBuilder::TakeString() {
271   void *Mem = Allocator.Allocate(
272                   sizeof(CodeCompletionString) + sizeof(Chunk) * Chunks.size()
273                                     + sizeof(const char *) * Annotations.size(),
274                                  llvm::alignOf<CodeCompletionString>());
275   CodeCompletionString *Result
276     = new (Mem) CodeCompletionString(Chunks.data(), Chunks.size(),
277                                      Priority, Availability,
278                                      Annotations.data(), Annotations.size(),
279                                      ParentKind, ParentName);
280   Chunks.clear();
281   return Result;
282 }
283 
284 void CodeCompletionBuilder::AddTypedTextChunk(const char *Text) {
285   Chunks.push_back(Chunk(CodeCompletionString::CK_TypedText, Text));
286 }
287 
288 void CodeCompletionBuilder::AddTextChunk(const char *Text) {
289   Chunks.push_back(Chunk::CreateText(Text));
290 }
291 
292 void CodeCompletionBuilder::AddOptionalChunk(CodeCompletionString *Optional) {
293   Chunks.push_back(Chunk::CreateOptional(Optional));
294 }
295 
296 void CodeCompletionBuilder::AddPlaceholderChunk(const char *Placeholder) {
297   Chunks.push_back(Chunk::CreatePlaceholder(Placeholder));
298 }
299 
300 void CodeCompletionBuilder::AddInformativeChunk(const char *Text) {
301   Chunks.push_back(Chunk::CreateInformative(Text));
302 }
303 
304 void CodeCompletionBuilder::AddResultTypeChunk(const char *ResultType) {
305   Chunks.push_back(Chunk::CreateResultType(ResultType));
306 }
307 
308 void
309 CodeCompletionBuilder::AddCurrentParameterChunk(const char *CurrentParameter) {
310   Chunks.push_back(Chunk::CreateCurrentParameter(CurrentParameter));
311 }
312 
313 void CodeCompletionBuilder::AddChunk(CodeCompletionString::ChunkKind CK,
314                                      const char *Text) {
315   Chunks.push_back(Chunk(CK, Text));
316 }
317 
318 void CodeCompletionBuilder::addParentContext(DeclContext *DC) {
319   if (DC->isTranslationUnit()) {
320     ParentKind = CXCursor_TranslationUnit;
321     return;
322   }
323 
324   if (DC->isFunctionOrMethod())
325     return;
326 
327   NamedDecl *ND = dyn_cast<NamedDecl>(DC);
328   if (!ND)
329     return;
330 
331   ParentKind = getCursorKindForDecl(ND);
332 
333   // Check whether we've already cached the parent name.
334   StringRef &CachedParentName = Allocator.getParentNames()[DC];
335   if (!CachedParentName.empty()) {
336     ParentName = CachedParentName;
337     return;
338   }
339 
340   // Find the interesting names.
341   llvm::SmallVector<DeclContext *, 2> Contexts;
342   while (DC && !DC->isFunctionOrMethod()) {
343     if (NamedDecl *ND = dyn_cast<NamedDecl>(DC)) {
344       if (ND->getIdentifier())
345         Contexts.push_back(DC);
346     }
347 
348     DC = DC->getParent();
349   }
350 
351   {
352     llvm::SmallString<128> S;
353     llvm::raw_svector_ostream OS(S);
354     bool First = true;
355     for (unsigned I = Contexts.size(); I != 0; --I) {
356       if (First)
357         First = false;
358       else {
359         OS << "::";
360       }
361 
362       DeclContext *CurDC = Contexts[I-1];
363       if (ObjCCategoryImplDecl *CatImpl = dyn_cast<ObjCCategoryImplDecl>(CurDC))
364         CurDC = CatImpl->getCategoryDecl();
365 
366       if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CurDC)) {
367         ObjCInterfaceDecl *Interface = Cat->getClassInterface();
368         if (!Interface)
369           return;
370 
371         OS << Interface->getName() << '(' << Cat->getName() << ')';
372       } else {
373         OS << cast<NamedDecl>(CurDC)->getName();
374       }
375     }
376 
377     ParentName = Allocator.CopyString(OS.str());
378     CachedParentName = ParentName;
379   }
380 }
381 
382 unsigned CodeCompletionResult::getPriorityFromDecl(NamedDecl *ND) {
383   if (!ND)
384     return CCP_Unlikely;
385 
386   // Context-based decisions.
387   DeclContext *DC = ND->getDeclContext()->getRedeclContext();
388   if (DC->isFunctionOrMethod() || isa<BlockDecl>(DC)) {
389     // _cmd is relatively rare
390     if (ImplicitParamDecl *ImplicitParam = dyn_cast<ImplicitParamDecl>(ND))
391       if (ImplicitParam->getIdentifier() &&
392           ImplicitParam->getIdentifier()->isStr("_cmd"))
393         return CCP_ObjC_cmd;
394 
395     return CCP_LocalDeclaration;
396   }
397   if (DC->isRecord() || isa<ObjCContainerDecl>(DC))
398     return CCP_MemberDeclaration;
399 
400   // Content-based decisions.
401   if (isa<EnumConstantDecl>(ND))
402     return CCP_Constant;
403   if (isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND))
404     return CCP_Type;
405 
406   return CCP_Declaration;
407 }
408 
409 //===----------------------------------------------------------------------===//
410 // Code completion overload candidate implementation
411 //===----------------------------------------------------------------------===//
412 FunctionDecl *
413 CodeCompleteConsumer::OverloadCandidate::getFunction() const {
414   if (getKind() == CK_Function)
415     return Function;
416   else if (getKind() == CK_FunctionTemplate)
417     return FunctionTemplate->getTemplatedDecl();
418   else
419     return 0;
420 }
421 
422 const FunctionType *
423 CodeCompleteConsumer::OverloadCandidate::getFunctionType() const {
424   switch (Kind) {
425   case CK_Function:
426     return Function->getType()->getAs<FunctionType>();
427 
428   case CK_FunctionTemplate:
429     return FunctionTemplate->getTemplatedDecl()->getType()
430              ->getAs<FunctionType>();
431 
432   case CK_FunctionType:
433     return Type;
434   }
435 
436   llvm_unreachable("Invalid CandidateKind!");
437 }
438 
439 //===----------------------------------------------------------------------===//
440 // Code completion consumer implementation
441 //===----------------------------------------------------------------------===//
442 
443 CodeCompleteConsumer::~CodeCompleteConsumer() { }
444 
445 void
446 PrintingCodeCompleteConsumer::ProcessCodeCompleteResults(Sema &SemaRef,
447                                                  CodeCompletionContext Context,
448                                                  CodeCompletionResult *Results,
449                                                          unsigned NumResults) {
450   std::stable_sort(Results, Results + NumResults);
451 
452   // Print the results.
453   for (unsigned I = 0; I != NumResults; ++I) {
454     OS << "COMPLETION: ";
455     switch (Results[I].Kind) {
456     case CodeCompletionResult::RK_Declaration:
457       OS << *Results[I].Declaration;
458       if (Results[I].Hidden)
459         OS << " (Hidden)";
460       if (CodeCompletionString *CCS
461             = Results[I].CreateCodeCompletionString(SemaRef, Allocator)) {
462         OS << " : " << CCS->getAsString();
463       }
464 
465       OS << '\n';
466       break;
467 
468     case CodeCompletionResult::RK_Keyword:
469       OS << Results[I].Keyword << '\n';
470       break;
471 
472     case CodeCompletionResult::RK_Macro: {
473       OS << Results[I].Macro->getName();
474       if (CodeCompletionString *CCS
475             = Results[I].CreateCodeCompletionString(SemaRef, Allocator)) {
476         OS << " : " << CCS->getAsString();
477       }
478       OS << '\n';
479       break;
480     }
481 
482     case CodeCompletionResult::RK_Pattern: {
483       OS << "Pattern : "
484          << Results[I].Pattern->getAsString() << '\n';
485       break;
486     }
487     }
488   }
489 }
490 
491 void
492 PrintingCodeCompleteConsumer::ProcessOverloadCandidates(Sema &SemaRef,
493                                                         unsigned CurrentArg,
494                                               OverloadCandidate *Candidates,
495                                                      unsigned NumCandidates) {
496   for (unsigned I = 0; I != NumCandidates; ++I) {
497     if (CodeCompletionString *CCS
498           = Candidates[I].CreateSignatureString(CurrentArg, SemaRef,
499                                                 Allocator)) {
500       OS << "OVERLOAD: " << CCS->getAsString() << "\n";
501     }
502   }
503 }
504 
505 /// \brief Retrieve the effective availability of the given declaration.
506 static AvailabilityResult getDeclAvailability(Decl *D) {
507   AvailabilityResult AR = D->getAvailability();
508   if (isa<EnumConstantDecl>(D))
509     AR = std::max(AR, cast<Decl>(D->getDeclContext())->getAvailability());
510   return AR;
511 }
512 
513 void CodeCompletionResult::computeCursorKindAndAvailability(bool Accessible) {
514   switch (Kind) {
515   case RK_Pattern:
516     if (!Declaration) {
517       // Do nothing: Patterns can come with cursor kinds!
518       break;
519     }
520     // Fall through
521 
522   case RK_Declaration: {
523     // Set the availability based on attributes.
524     switch (getDeclAvailability(Declaration)) {
525     case AR_Available:
526     case AR_NotYetIntroduced:
527       Availability = CXAvailability_Available;
528       break;
529 
530     case AR_Deprecated:
531       Availability = CXAvailability_Deprecated;
532       break;
533 
534     case AR_Unavailable:
535       Availability = CXAvailability_NotAvailable;
536       break;
537     }
538 
539     if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Declaration))
540       if (Function->isDeleted())
541         Availability = CXAvailability_NotAvailable;
542 
543     CursorKind = getCursorKindForDecl(Declaration);
544     if (CursorKind == CXCursor_UnexposedDecl) {
545       // FIXME: Forward declarations of Objective-C classes and protocols
546       // are not directly exposed, but we want code completion to treat them
547       // like a definition.
548       if (isa<ObjCInterfaceDecl>(Declaration))
549         CursorKind = CXCursor_ObjCInterfaceDecl;
550       else if (isa<ObjCProtocolDecl>(Declaration))
551         CursorKind = CXCursor_ObjCProtocolDecl;
552       else
553         CursorKind = CXCursor_NotImplemented;
554     }
555     break;
556   }
557 
558   case RK_Macro:
559     Availability = CXAvailability_Available;
560     CursorKind = CXCursor_MacroDefinition;
561     break;
562 
563   case RK_Keyword:
564     Availability = CXAvailability_Available;
565     CursorKind = CXCursor_NotImplemented;
566     break;
567   }
568 
569   if (!Accessible)
570     Availability = CXAvailability_NotAccessible;
571 }
572 
573 /// \brief Retrieve the name that should be used to order a result.
574 ///
575 /// If the name needs to be constructed as a string, that string will be
576 /// saved into Saved and the returned StringRef will refer to it.
577 static StringRef getOrderedName(const CodeCompletionResult &R,
578                                     std::string &Saved) {
579   switch (R.Kind) {
580     case CodeCompletionResult::RK_Keyword:
581       return R.Keyword;
582 
583     case CodeCompletionResult::RK_Pattern:
584       return R.Pattern->getTypedText();
585 
586     case CodeCompletionResult::RK_Macro:
587       return R.Macro->getName();
588 
589     case CodeCompletionResult::RK_Declaration:
590       // Handle declarations below.
591       break;
592   }
593 
594   DeclarationName Name = R.Declaration->getDeclName();
595 
596   // If the name is a simple identifier (by far the common case), or a
597   // zero-argument selector, just return a reference to that identifier.
598   if (IdentifierInfo *Id = Name.getAsIdentifierInfo())
599     return Id->getName();
600   if (Name.isObjCZeroArgSelector())
601     if (IdentifierInfo *Id
602         = Name.getObjCSelector().getIdentifierInfoForSlot(0))
603       return Id->getName();
604 
605   Saved = Name.getAsString();
606   return Saved;
607 }
608 
609 bool clang::operator<(const CodeCompletionResult &X,
610                       const CodeCompletionResult &Y) {
611   std::string XSaved, YSaved;
612   StringRef XStr = getOrderedName(X, XSaved);
613   StringRef YStr = getOrderedName(Y, YSaved);
614   int cmp = XStr.compare_lower(YStr);
615   if (cmp)
616     return cmp < 0;
617 
618   // If case-insensitive comparison fails, try case-sensitive comparison.
619   cmp = XStr.compare(YStr);
620   if (cmp)
621     return cmp < 0;
622 
623   return false;
624 }
625