1 //===- CIndexCodeCompletion.cpp - Code Completion API hooks ---------------===//
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 Clang-C Source Indexing library hooks for
10 // code completion.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "CIndexer.h"
15 #include "CIndexDiagnostic.h"
16 #include "CLog.h"
17 #include "CXCursor.h"
18 #include "CXSourceLocation.h"
19 #include "CXString.h"
20 #include "CXTranslationUnit.h"
21 #include "clang/AST/Decl.h"
22 #include "clang/AST/DeclObjC.h"
23 #include "clang/AST/Type.h"
24 #include "clang/Basic/FileManager.h"
25 #include "clang/Basic/SourceManager.h"
26 #include "clang/Frontend/ASTUnit.h"
27 #include "clang/Frontend/CompilerInstance.h"
28 #include "clang/Sema/CodeCompleteConsumer.h"
29 #include "clang/Sema/Sema.h"
30 #include "llvm/ADT/SmallString.h"
31 #include "llvm/ADT/StringExtras.h"
32 #include "llvm/Support/CrashRecoveryContext.h"
33 #include "llvm/Support/FileSystem.h"
34 #include "llvm/Support/FormatVariadic.h"
35 #include "llvm/Support/MemoryBuffer.h"
36 #include "llvm/Support/Program.h"
37 #include "llvm/Support/Timer.h"
38 #include "llvm/Support/raw_ostream.h"
39 #include <atomic>
40 #include <cstdio>
41 #include <cstdlib>
42 #include <string>
43 
44 
45 #ifdef UDP_CODE_COMPLETION_LOGGER
46 #include "clang/Basic/Version.h"
47 #include <arpa/inet.h>
48 #include <sys/socket.h>
49 #include <sys/types.h>
50 #include <unistd.h>
51 #endif
52 
53 using namespace clang;
54 using namespace clang::cxindex;
55 
56 enum CXCompletionChunkKind
57 clang_getCompletionChunkKind(CXCompletionString completion_string,
58                              unsigned chunk_number) {
59   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
60   if (!CCStr || chunk_number >= CCStr->size())
61     return CXCompletionChunk_Text;
62 
63   switch ((*CCStr)[chunk_number].Kind) {
64   case CodeCompletionString::CK_TypedText:
65     return CXCompletionChunk_TypedText;
66   case CodeCompletionString::CK_Text:
67     return CXCompletionChunk_Text;
68   case CodeCompletionString::CK_Optional:
69     return CXCompletionChunk_Optional;
70   case CodeCompletionString::CK_Placeholder:
71     return CXCompletionChunk_Placeholder;
72   case CodeCompletionString::CK_Informative:
73     return CXCompletionChunk_Informative;
74   case CodeCompletionString::CK_ResultType:
75     return CXCompletionChunk_ResultType;
76   case CodeCompletionString::CK_CurrentParameter:
77     return CXCompletionChunk_CurrentParameter;
78   case CodeCompletionString::CK_LeftParen:
79     return CXCompletionChunk_LeftParen;
80   case CodeCompletionString::CK_RightParen:
81     return CXCompletionChunk_RightParen;
82   case CodeCompletionString::CK_LeftBracket:
83     return CXCompletionChunk_LeftBracket;
84   case CodeCompletionString::CK_RightBracket:
85     return CXCompletionChunk_RightBracket;
86   case CodeCompletionString::CK_LeftBrace:
87     return CXCompletionChunk_LeftBrace;
88   case CodeCompletionString::CK_RightBrace:
89     return CXCompletionChunk_RightBrace;
90   case CodeCompletionString::CK_LeftAngle:
91     return CXCompletionChunk_LeftAngle;
92   case CodeCompletionString::CK_RightAngle:
93     return CXCompletionChunk_RightAngle;
94   case CodeCompletionString::CK_Comma:
95     return CXCompletionChunk_Comma;
96   case CodeCompletionString::CK_Colon:
97     return CXCompletionChunk_Colon;
98   case CodeCompletionString::CK_SemiColon:
99     return CXCompletionChunk_SemiColon;
100   case CodeCompletionString::CK_Equal:
101     return CXCompletionChunk_Equal;
102   case CodeCompletionString::CK_HorizontalSpace:
103     return CXCompletionChunk_HorizontalSpace;
104   case CodeCompletionString::CK_VerticalSpace:
105     return CXCompletionChunk_VerticalSpace;
106   }
107 
108   llvm_unreachable("Invalid CompletionKind!");
109 }
110 
111 CXString clang_getCompletionChunkText(CXCompletionString completion_string,
112                                       unsigned chunk_number) {
113   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
114   if (!CCStr || chunk_number >= CCStr->size())
115     return cxstring::createNull();
116 
117   switch ((*CCStr)[chunk_number].Kind) {
118   case CodeCompletionString::CK_TypedText:
119   case CodeCompletionString::CK_Text:
120   case CodeCompletionString::CK_Placeholder:
121   case CodeCompletionString::CK_CurrentParameter:
122   case CodeCompletionString::CK_Informative:
123   case CodeCompletionString::CK_LeftParen:
124   case CodeCompletionString::CK_RightParen:
125   case CodeCompletionString::CK_LeftBracket:
126   case CodeCompletionString::CK_RightBracket:
127   case CodeCompletionString::CK_LeftBrace:
128   case CodeCompletionString::CK_RightBrace:
129   case CodeCompletionString::CK_LeftAngle:
130   case CodeCompletionString::CK_RightAngle:
131   case CodeCompletionString::CK_Comma:
132   case CodeCompletionString::CK_ResultType:
133   case CodeCompletionString::CK_Colon:
134   case CodeCompletionString::CK_SemiColon:
135   case CodeCompletionString::CK_Equal:
136   case CodeCompletionString::CK_HorizontalSpace:
137   case CodeCompletionString::CK_VerticalSpace:
138     return cxstring::createRef((*CCStr)[chunk_number].Text);
139 
140   case CodeCompletionString::CK_Optional:
141     // Note: treated as an empty text block.
142     return cxstring::createEmpty();
143   }
144 
145   llvm_unreachable("Invalid CodeCompletionString Kind!");
146 }
147 
148 
149 CXCompletionString
150 clang_getCompletionChunkCompletionString(CXCompletionString completion_string,
151                                          unsigned chunk_number) {
152   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
153   if (!CCStr || chunk_number >= CCStr->size())
154     return nullptr;
155 
156   switch ((*CCStr)[chunk_number].Kind) {
157   case CodeCompletionString::CK_TypedText:
158   case CodeCompletionString::CK_Text:
159   case CodeCompletionString::CK_Placeholder:
160   case CodeCompletionString::CK_CurrentParameter:
161   case CodeCompletionString::CK_Informative:
162   case CodeCompletionString::CK_LeftParen:
163   case CodeCompletionString::CK_RightParen:
164   case CodeCompletionString::CK_LeftBracket:
165   case CodeCompletionString::CK_RightBracket:
166   case CodeCompletionString::CK_LeftBrace:
167   case CodeCompletionString::CK_RightBrace:
168   case CodeCompletionString::CK_LeftAngle:
169   case CodeCompletionString::CK_RightAngle:
170   case CodeCompletionString::CK_Comma:
171   case CodeCompletionString::CK_ResultType:
172   case CodeCompletionString::CK_Colon:
173   case CodeCompletionString::CK_SemiColon:
174   case CodeCompletionString::CK_Equal:
175   case CodeCompletionString::CK_HorizontalSpace:
176   case CodeCompletionString::CK_VerticalSpace:
177     return nullptr;
178 
179   case CodeCompletionString::CK_Optional:
180     // Note: treated as an empty text block.
181     return (*CCStr)[chunk_number].Optional;
182   }
183 
184   llvm_unreachable("Invalid CompletionKind!");
185 }
186 
187 unsigned clang_getNumCompletionChunks(CXCompletionString completion_string) {
188   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
189   return CCStr? CCStr->size() : 0;
190 }
191 
192 unsigned clang_getCompletionPriority(CXCompletionString completion_string) {
193   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
194   return CCStr? CCStr->getPriority() : unsigned(CCP_Unlikely);
195 }
196 
197 enum CXAvailabilityKind
198 clang_getCompletionAvailability(CXCompletionString completion_string) {
199   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
200   return CCStr? static_cast<CXAvailabilityKind>(CCStr->getAvailability())
201               : CXAvailability_Available;
202 }
203 
204 unsigned clang_getCompletionNumAnnotations(CXCompletionString completion_string)
205 {
206   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
207   return CCStr ? CCStr->getAnnotationCount() : 0;
208 }
209 
210 CXString clang_getCompletionAnnotation(CXCompletionString completion_string,
211                                        unsigned annotation_number) {
212   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
213   return CCStr ? cxstring::createRef(CCStr->getAnnotation(annotation_number))
214                : cxstring::createNull();
215 }
216 
217 CXString
218 clang_getCompletionParent(CXCompletionString completion_string,
219                           CXCursorKind *kind) {
220   if (kind)
221     *kind = CXCursor_NotImplemented;
222 
223   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
224   if (!CCStr)
225     return cxstring::createNull();
226 
227   return cxstring::createRef(CCStr->getParentContextName());
228 }
229 
230 CXString
231 clang_getCompletionBriefComment(CXCompletionString completion_string) {
232   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
233 
234   if (!CCStr)
235     return cxstring::createNull();
236 
237   return cxstring::createRef(CCStr->getBriefComment());
238 }
239 
240 namespace {
241 
242 /// The CXCodeCompleteResults structure we allocate internally;
243 /// the client only sees the initial CXCodeCompleteResults structure.
244 ///
245 /// Normally, clients of CXString shouldn't care whether or not a CXString is
246 /// managed by a pool or by explicitly malloc'ed memory.  But
247 /// AllocatedCXCodeCompleteResults outlives the CXTranslationUnit, so we can
248 /// not rely on the StringPool in the TU.
249 struct AllocatedCXCodeCompleteResults : public CXCodeCompleteResults {
250   AllocatedCXCodeCompleteResults(IntrusiveRefCntPtr<FileManager> FileMgr);
251   ~AllocatedCXCodeCompleteResults();
252 
253   /// Diagnostics produced while performing code completion.
254   SmallVector<StoredDiagnostic, 8> Diagnostics;
255 
256   /// Allocated API-exposed wrappters for Diagnostics.
257   SmallVector<CXStoredDiagnostic *, 8> DiagnosticsWrappers;
258 
259   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts;
260 
261   /// Diag object
262   IntrusiveRefCntPtr<DiagnosticsEngine> Diag;
263 
264   /// Language options used to adjust source locations.
265   LangOptions LangOpts;
266 
267   /// File manager, used for diagnostics.
268   IntrusiveRefCntPtr<FileManager> FileMgr;
269 
270   /// Source manager, used for diagnostics.
271   IntrusiveRefCntPtr<SourceManager> SourceMgr;
272 
273   /// Temporary buffers that will be deleted once we have finished with
274   /// the code-completion results.
275   SmallVector<const llvm::MemoryBuffer *, 1> TemporaryBuffers;
276 
277   /// Allocator used to store globally cached code-completion results.
278   std::shared_ptr<clang::GlobalCodeCompletionAllocator>
279       CachedCompletionAllocator;
280 
281   /// Allocator used to store code completion results.
282   std::shared_ptr<clang::GlobalCodeCompletionAllocator> CodeCompletionAllocator;
283 
284   /// Context under which completion occurred.
285   enum clang::CodeCompletionContext::Kind ContextKind;
286 
287   /// A bitfield representing the acceptable completions for the
288   /// current context.
289   unsigned long long Contexts;
290 
291   /// The kind of the container for the current context for completions.
292   enum CXCursorKind ContainerKind;
293 
294   /// The USR of the container for the current context for completions.
295   std::string ContainerUSR;
296 
297   /// a boolean value indicating whether there is complete information
298   /// about the container
299   unsigned ContainerIsIncomplete;
300 
301   /// A string containing the Objective-C selector entered thus far for a
302   /// message send.
303   std::string Selector;
304 
305   /// Vector of fix-its for each completion result that *must* be applied
306   /// before that result for the corresponding completion item.
307   std::vector<std::vector<FixItHint>> FixItsVector;
308 };
309 
310 } // end anonymous namespace
311 
312 unsigned clang_getCompletionNumFixIts(CXCodeCompleteResults *results,
313                                       unsigned completion_index) {
314   AllocatedCXCodeCompleteResults *allocated_results = (AllocatedCXCodeCompleteResults *)results;
315 
316   if (!allocated_results || allocated_results->FixItsVector.size() <= completion_index)
317     return 0;
318 
319   return static_cast<unsigned>(allocated_results->FixItsVector[completion_index].size());
320 }
321 
322 CXString clang_getCompletionFixIt(CXCodeCompleteResults *results,
323                                   unsigned completion_index,
324                                   unsigned fixit_index,
325                                   CXSourceRange *replacement_range) {
326   AllocatedCXCodeCompleteResults *allocated_results = (AllocatedCXCodeCompleteResults *)results;
327 
328   if (!allocated_results || allocated_results->FixItsVector.size() <= completion_index) {
329     if (replacement_range)
330       *replacement_range = clang_getNullRange();
331     return cxstring::createNull();
332   }
333 
334   ArrayRef<FixItHint> FixIts = allocated_results->FixItsVector[completion_index];
335   if (FixIts.size() <= fixit_index) {
336     if (replacement_range)
337       *replacement_range = clang_getNullRange();
338     return cxstring::createNull();
339   }
340 
341   const FixItHint &FixIt = FixIts[fixit_index];
342   if (replacement_range) {
343     *replacement_range = cxloc::translateSourceRange(
344         *allocated_results->SourceMgr, allocated_results->LangOpts,
345         FixIt.RemoveRange);
346   }
347 
348   return cxstring::createRef(FixIt.CodeToInsert.c_str());
349 }
350 
351 /// Tracks the number of code-completion result objects that are
352 /// currently active.
353 ///
354 /// Used for debugging purposes only.
355 static std::atomic<unsigned> CodeCompletionResultObjects;
356 
357 AllocatedCXCodeCompleteResults::AllocatedCXCodeCompleteResults(
358     IntrusiveRefCntPtr<FileManager> FileMgr)
359     : CXCodeCompleteResults(), DiagOpts(new DiagnosticOptions),
360       Diag(new DiagnosticsEngine(
361           IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs), &*DiagOpts)),
362       FileMgr(std::move(FileMgr)),
363       SourceMgr(new SourceManager(*Diag, *this->FileMgr)),
364       CodeCompletionAllocator(
365           std::make_shared<clang::GlobalCodeCompletionAllocator>()),
366       Contexts(CXCompletionContext_Unknown),
367       ContainerKind(CXCursor_InvalidCode), ContainerIsIncomplete(1) {
368   if (getenv("LIBCLANG_OBJTRACKING"))
369     fprintf(stderr, "+++ %u completion results\n",
370             ++CodeCompletionResultObjects);
371 }
372 
373 AllocatedCXCodeCompleteResults::~AllocatedCXCodeCompleteResults() {
374   llvm::DeleteContainerPointers(DiagnosticsWrappers);
375   delete [] Results;
376 
377   for (unsigned I = 0, N = TemporaryBuffers.size(); I != N; ++I)
378     delete TemporaryBuffers[I];
379 
380   if (getenv("LIBCLANG_OBJTRACKING"))
381     fprintf(stderr, "--- %u completion results\n",
382             --CodeCompletionResultObjects);
383 }
384 
385 static unsigned long long getContextsForContextKind(
386                                           enum CodeCompletionContext::Kind kind,
387                                                     Sema &S) {
388   unsigned long long contexts = 0;
389   switch (kind) {
390     case CodeCompletionContext::CCC_OtherWithMacros: {
391       //We can allow macros here, but we don't know what else is permissible
392       //So we'll say the only thing permissible are macros
393       contexts = CXCompletionContext_MacroName;
394       break;
395     }
396     case CodeCompletionContext::CCC_TopLevel:
397     case CodeCompletionContext::CCC_ObjCIvarList:
398     case CodeCompletionContext::CCC_ClassStructUnion:
399     case CodeCompletionContext::CCC_Type: {
400       contexts = CXCompletionContext_AnyType |
401                  CXCompletionContext_ObjCInterface;
402       if (S.getLangOpts().CPlusPlus) {
403         contexts |= CXCompletionContext_EnumTag |
404                     CXCompletionContext_UnionTag |
405                     CXCompletionContext_StructTag |
406                     CXCompletionContext_ClassTag |
407                     CXCompletionContext_NestedNameSpecifier;
408       }
409       break;
410     }
411     case CodeCompletionContext::CCC_Statement: {
412       contexts = CXCompletionContext_AnyType |
413                  CXCompletionContext_ObjCInterface |
414                  CXCompletionContext_AnyValue;
415       if (S.getLangOpts().CPlusPlus) {
416         contexts |= CXCompletionContext_EnumTag |
417                     CXCompletionContext_UnionTag |
418                     CXCompletionContext_StructTag |
419                     CXCompletionContext_ClassTag |
420                     CXCompletionContext_NestedNameSpecifier;
421       }
422       break;
423     }
424     case CodeCompletionContext::CCC_Expression: {
425       contexts = CXCompletionContext_AnyValue;
426       if (S.getLangOpts().CPlusPlus) {
427         contexts |= CXCompletionContext_AnyType |
428                     CXCompletionContext_ObjCInterface |
429                     CXCompletionContext_EnumTag |
430                     CXCompletionContext_UnionTag |
431                     CXCompletionContext_StructTag |
432                     CXCompletionContext_ClassTag |
433                     CXCompletionContext_NestedNameSpecifier;
434       }
435       break;
436     }
437     case CodeCompletionContext::CCC_ObjCMessageReceiver: {
438       contexts = CXCompletionContext_ObjCObjectValue |
439                  CXCompletionContext_ObjCSelectorValue |
440                  CXCompletionContext_ObjCInterface;
441       if (S.getLangOpts().CPlusPlus) {
442         contexts |= CXCompletionContext_CXXClassTypeValue |
443                     CXCompletionContext_AnyType |
444                     CXCompletionContext_EnumTag |
445                     CXCompletionContext_UnionTag |
446                     CXCompletionContext_StructTag |
447                     CXCompletionContext_ClassTag |
448                     CXCompletionContext_NestedNameSpecifier;
449       }
450       break;
451     }
452     case CodeCompletionContext::CCC_DotMemberAccess: {
453       contexts = CXCompletionContext_DotMemberAccess;
454       break;
455     }
456     case CodeCompletionContext::CCC_ArrowMemberAccess: {
457       contexts = CXCompletionContext_ArrowMemberAccess;
458       break;
459     }
460     case CodeCompletionContext::CCC_ObjCPropertyAccess: {
461       contexts = CXCompletionContext_ObjCPropertyAccess;
462       break;
463     }
464     case CodeCompletionContext::CCC_EnumTag: {
465       contexts = CXCompletionContext_EnumTag |
466                  CXCompletionContext_NestedNameSpecifier;
467       break;
468     }
469     case CodeCompletionContext::CCC_UnionTag: {
470       contexts = CXCompletionContext_UnionTag |
471                  CXCompletionContext_NestedNameSpecifier;
472       break;
473     }
474     case CodeCompletionContext::CCC_ClassOrStructTag: {
475       contexts = CXCompletionContext_StructTag |
476                  CXCompletionContext_ClassTag |
477                  CXCompletionContext_NestedNameSpecifier;
478       break;
479     }
480     case CodeCompletionContext::CCC_ObjCProtocolName: {
481       contexts = CXCompletionContext_ObjCProtocol;
482       break;
483     }
484     case CodeCompletionContext::CCC_Namespace: {
485       contexts = CXCompletionContext_Namespace;
486       break;
487     }
488     case CodeCompletionContext::CCC_SymbolOrNewName:
489     case CodeCompletionContext::CCC_Symbol: {
490       contexts = CXCompletionContext_NestedNameSpecifier;
491       break;
492     }
493     case CodeCompletionContext::CCC_MacroNameUse: {
494       contexts = CXCompletionContext_MacroName;
495       break;
496     }
497     case CodeCompletionContext::CCC_NaturalLanguage: {
498       contexts = CXCompletionContext_NaturalLanguage;
499       break;
500     }
501     case CodeCompletionContext::CCC_IncludedFile: {
502       contexts = CXCompletionContext_IncludedFile;
503       break;
504     }
505     case CodeCompletionContext::CCC_SelectorName: {
506       contexts = CXCompletionContext_ObjCSelectorName;
507       break;
508     }
509     case CodeCompletionContext::CCC_ParenthesizedExpression: {
510       contexts = CXCompletionContext_AnyType |
511                  CXCompletionContext_ObjCInterface |
512                  CXCompletionContext_AnyValue;
513       if (S.getLangOpts().CPlusPlus) {
514         contexts |= CXCompletionContext_EnumTag |
515                     CXCompletionContext_UnionTag |
516                     CXCompletionContext_StructTag |
517                     CXCompletionContext_ClassTag |
518                     CXCompletionContext_NestedNameSpecifier;
519       }
520       break;
521     }
522     case CodeCompletionContext::CCC_ObjCInstanceMessage: {
523       contexts = CXCompletionContext_ObjCInstanceMessage;
524       break;
525     }
526     case CodeCompletionContext::CCC_ObjCClassMessage: {
527       contexts = CXCompletionContext_ObjCClassMessage;
528       break;
529     }
530     case CodeCompletionContext::CCC_ObjCInterfaceName: {
531       contexts = CXCompletionContext_ObjCInterface;
532       break;
533     }
534     case CodeCompletionContext::CCC_ObjCCategoryName: {
535       contexts = CXCompletionContext_ObjCCategory;
536       break;
537     }
538     case CodeCompletionContext::CCC_Other:
539     case CodeCompletionContext::CCC_ObjCInterface:
540     case CodeCompletionContext::CCC_ObjCImplementation:
541     case CodeCompletionContext::CCC_NewName:
542     case CodeCompletionContext::CCC_MacroName:
543     case CodeCompletionContext::CCC_PreprocessorExpression:
544     case CodeCompletionContext::CCC_PreprocessorDirective:
545     case CodeCompletionContext::CCC_TypeQualifiers: {
546       //Only Clang results should be accepted, so we'll set all of the other
547       //context bits to 0 (i.e. the empty set)
548       contexts = CXCompletionContext_Unexposed;
549       break;
550     }
551     case CodeCompletionContext::CCC_Recovery: {
552       //We don't know what the current context is, so we'll return unknown
553       //This is the equivalent of setting all of the other context bits
554       contexts = CXCompletionContext_Unknown;
555       break;
556     }
557   }
558   return contexts;
559 }
560 
561 namespace {
562   class CaptureCompletionResults : public CodeCompleteConsumer {
563     AllocatedCXCodeCompleteResults &AllocatedResults;
564     CodeCompletionTUInfo CCTUInfo;
565     SmallVector<CXCompletionResult, 16> StoredResults;
566     CXTranslationUnit *TU;
567   public:
568     CaptureCompletionResults(const CodeCompleteOptions &Opts,
569                              AllocatedCXCodeCompleteResults &Results,
570                              CXTranslationUnit *TranslationUnit)
571       : CodeCompleteConsumer(Opts, false),
572         AllocatedResults(Results), CCTUInfo(Results.CodeCompletionAllocator),
573         TU(TranslationUnit) { }
574     ~CaptureCompletionResults() override { Finish(); }
575 
576     void ProcessCodeCompleteResults(Sema &S,
577                                     CodeCompletionContext Context,
578                                     CodeCompletionResult *Results,
579                                     unsigned NumResults) override {
580       StoredResults.reserve(StoredResults.size() + NumResults);
581       if (includeFixIts())
582         AllocatedResults.FixItsVector.reserve(NumResults);
583       for (unsigned I = 0; I != NumResults; ++I) {
584         CodeCompletionString *StoredCompletion
585           = Results[I].CreateCodeCompletionString(S, Context, getAllocator(),
586                                                   getCodeCompletionTUInfo(),
587                                                   includeBriefComments());
588 
589         CXCompletionResult R;
590         R.CursorKind = Results[I].CursorKind;
591         R.CompletionString = StoredCompletion;
592         StoredResults.push_back(R);
593         if (includeFixIts())
594           AllocatedResults.FixItsVector.emplace_back(std::move(Results[I].FixIts));
595       }
596 
597       enum CodeCompletionContext::Kind contextKind = Context.getKind();
598 
599       AllocatedResults.ContextKind = contextKind;
600       AllocatedResults.Contexts = getContextsForContextKind(contextKind, S);
601 
602       AllocatedResults.Selector = "";
603       ArrayRef<IdentifierInfo *> SelIdents = Context.getSelIdents();
604       for (ArrayRef<IdentifierInfo *>::iterator I = SelIdents.begin(),
605                                                 E = SelIdents.end();
606            I != E; ++I) {
607         if (IdentifierInfo *selIdent = *I)
608           AllocatedResults.Selector += selIdent->getName();
609         AllocatedResults.Selector += ":";
610       }
611 
612       QualType baseType = Context.getBaseType();
613       NamedDecl *D = nullptr;
614 
615       if (!baseType.isNull()) {
616         // Get the declaration for a class/struct/union/enum type
617         if (const TagType *Tag = baseType->getAs<TagType>())
618           D = Tag->getDecl();
619         // Get the @interface declaration for a (possibly-qualified) Objective-C
620         // object pointer type, e.g., NSString*
621         else if (const ObjCObjectPointerType *ObjPtr =
622                  baseType->getAs<ObjCObjectPointerType>())
623           D = ObjPtr->getInterfaceDecl();
624         // Get the @interface declaration for an Objective-C object type
625         else if (const ObjCObjectType *Obj = baseType->getAs<ObjCObjectType>())
626           D = Obj->getInterface();
627         // Get the class for a C++ injected-class-name
628         else if (const InjectedClassNameType *Injected =
629                  baseType->getAs<InjectedClassNameType>())
630           D = Injected->getDecl();
631       }
632 
633       if (D != nullptr) {
634         CXCursor cursor = cxcursor::MakeCXCursor(D, *TU);
635 
636         AllocatedResults.ContainerKind = clang_getCursorKind(cursor);
637 
638         CXString CursorUSR = clang_getCursorUSR(cursor);
639         AllocatedResults.ContainerUSR = clang_getCString(CursorUSR);
640         clang_disposeString(CursorUSR);
641 
642         const Type *type = baseType.getTypePtrOrNull();
643         if (type) {
644           AllocatedResults.ContainerIsIncomplete = type->isIncompleteType();
645         }
646         else {
647           AllocatedResults.ContainerIsIncomplete = 1;
648         }
649       }
650       else {
651         AllocatedResults.ContainerKind = CXCursor_InvalidCode;
652         AllocatedResults.ContainerUSR.clear();
653         AllocatedResults.ContainerIsIncomplete = 1;
654       }
655     }
656 
657     void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
658                                    OverloadCandidate *Candidates,
659                                    unsigned NumCandidates,
660                                    SourceLocation OpenParLoc) override {
661       StoredResults.reserve(StoredResults.size() + NumCandidates);
662       for (unsigned I = 0; I != NumCandidates; ++I) {
663         CodeCompletionString *StoredCompletion
664           = Candidates[I].CreateSignatureString(CurrentArg, S, getAllocator(),
665                                                 getCodeCompletionTUInfo(),
666                                                 includeBriefComments());
667 
668         CXCompletionResult R;
669         R.CursorKind = CXCursor_OverloadCandidate;
670         R.CompletionString = StoredCompletion;
671         StoredResults.push_back(R);
672       }
673     }
674 
675     CodeCompletionAllocator &getAllocator() override {
676       return *AllocatedResults.CodeCompletionAllocator;
677     }
678 
679     CodeCompletionTUInfo &getCodeCompletionTUInfo() override { return CCTUInfo;}
680 
681   private:
682     void Finish() {
683       AllocatedResults.Results = new CXCompletionResult [StoredResults.size()];
684       AllocatedResults.NumResults = StoredResults.size();
685       std::memcpy(AllocatedResults.Results, StoredResults.data(),
686                   StoredResults.size() * sizeof(CXCompletionResult));
687       StoredResults.clear();
688     }
689   };
690 }
691 
692 static CXCodeCompleteResults *
693 clang_codeCompleteAt_Impl(CXTranslationUnit TU, const char *complete_filename,
694                           unsigned complete_line, unsigned complete_column,
695                           ArrayRef<CXUnsavedFile> unsaved_files,
696                           unsigned options) {
697   bool IncludeBriefComments = options & CXCodeComplete_IncludeBriefComments;
698   bool SkipPreamble = options & CXCodeComplete_SkipPreamble;
699   bool IncludeFixIts = options & CXCodeComplete_IncludeCompletionsWithFixIts;
700 
701 #ifdef UDP_CODE_COMPLETION_LOGGER
702 #ifdef UDP_CODE_COMPLETION_LOGGER_PORT
703   const llvm::TimeRecord &StartTime =  llvm::TimeRecord::getCurrentTime();
704 #endif
705 #endif
706   bool EnableLogging = getenv("LIBCLANG_CODE_COMPLETION_LOGGING") != nullptr;
707 
708   if (cxtu::isNotUsableTU(TU)) {
709     LOG_BAD_TU(TU);
710     return nullptr;
711   }
712 
713   ASTUnit *AST = cxtu::getASTUnit(TU);
714   if (!AST)
715     return nullptr;
716 
717   CIndexer *CXXIdx = TU->CIdx;
718   if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForEditing))
719     setThreadBackgroundPriority();
720 
721   ASTUnit::ConcurrencyCheck Check(*AST);
722 
723   // Perform the remapping of source files.
724   SmallVector<ASTUnit::RemappedFile, 4> RemappedFiles;
725 
726   for (auto &UF : unsaved_files) {
727     std::unique_ptr<llvm::MemoryBuffer> MB =
728         llvm::MemoryBuffer::getMemBufferCopy(getContents(UF), UF.Filename);
729     RemappedFiles.push_back(std::make_pair(UF.Filename, MB.release()));
730   }
731 
732   if (EnableLogging) {
733     // FIXME: Add logging.
734   }
735 
736   // Parse the resulting source file to find code-completion results.
737   AllocatedCXCodeCompleteResults *Results = new AllocatedCXCodeCompleteResults(
738       &AST->getFileManager());
739   Results->Results = nullptr;
740   Results->NumResults = 0;
741 
742   // Create a code-completion consumer to capture the results.
743   CodeCompleteOptions Opts;
744   Opts.IncludeBriefComments = IncludeBriefComments;
745   Opts.LoadExternal = !SkipPreamble;
746   Opts.IncludeFixIts = IncludeFixIts;
747   CaptureCompletionResults Capture(Opts, *Results, &TU);
748 
749   // Perform completion.
750   std::vector<const char *> CArgs;
751   for (const auto &Arg : TU->Arguments)
752     CArgs.push_back(Arg.c_str());
753   std::string CompletionInvocation =
754       llvm::formatv("-code-completion-at={0}:{1}:{2}", complete_filename,
755                     complete_line, complete_column)
756           .str();
757   LibclangInvocationReporter InvocationReporter(
758       *CXXIdx, LibclangInvocationReporter::OperationKind::CompletionOperation,
759       TU->ParsingOptions, CArgs, CompletionInvocation, unsaved_files);
760   AST->CodeComplete(complete_filename, complete_line, complete_column,
761                     RemappedFiles, (options & CXCodeComplete_IncludeMacros),
762                     (options & CXCodeComplete_IncludeCodePatterns),
763                     IncludeBriefComments, Capture,
764                     CXXIdx->getPCHContainerOperations(), *Results->Diag,
765                     Results->LangOpts, *Results->SourceMgr, *Results->FileMgr,
766                     Results->Diagnostics, Results->TemporaryBuffers);
767 
768   Results->DiagnosticsWrappers.resize(Results->Diagnostics.size());
769 
770   // Keep a reference to the allocator used for cached global completions, so
771   // that we can be sure that the memory used by our code completion strings
772   // doesn't get freed due to subsequent reparses (while the code completion
773   // results are still active).
774   Results->CachedCompletionAllocator = AST->getCachedCompletionAllocator();
775 
776 
777 
778 #ifdef UDP_CODE_COMPLETION_LOGGER
779 #ifdef UDP_CODE_COMPLETION_LOGGER_PORT
780   const llvm::TimeRecord &EndTime =  llvm::TimeRecord::getCurrentTime();
781   SmallString<256> LogResult;
782   llvm::raw_svector_ostream os(LogResult);
783 
784   // Figure out the language and whether or not it uses PCH.
785   const char *lang = 0;
786   bool usesPCH = false;
787 
788   for (std::vector<const char*>::iterator I = argv.begin(), E = argv.end();
789        I != E; ++I) {
790     if (*I == 0)
791       continue;
792     if (strcmp(*I, "-x") == 0) {
793       if (I + 1 != E) {
794         lang = *(++I);
795         continue;
796       }
797     }
798     else if (strcmp(*I, "-include") == 0) {
799       if (I+1 != E) {
800         const char *arg = *(++I);
801         SmallString<512> pchName;
802         {
803           llvm::raw_svector_ostream os(pchName);
804           os << arg << ".pth";
805         }
806         pchName.push_back('\0');
807         struct stat stat_results;
808         if (stat(pchName.str().c_str(), &stat_results) == 0)
809           usesPCH = true;
810         continue;
811       }
812     }
813   }
814 
815   os << "{ ";
816   os << "\"wall\": " << (EndTime.getWallTime() - StartTime.getWallTime());
817   os << ", \"numRes\": " << Results->NumResults;
818   os << ", \"diags\": " << Results->Diagnostics.size();
819   os << ", \"pch\": " << (usesPCH ? "true" : "false");
820   os << ", \"lang\": \"" << (lang ? lang : "<unknown>") << '"';
821   const char *name = getlogin();
822   os << ", \"user\": \"" << (name ? name : "unknown") << '"';
823   os << ", \"clangVer\": \"" << getClangFullVersion() << '"';
824   os << " }";
825 
826   StringRef res = os.str();
827   if (res.size() > 0) {
828     do {
829       // Setup the UDP socket.
830       struct sockaddr_in servaddr;
831       bzero(&servaddr, sizeof(servaddr));
832       servaddr.sin_family = AF_INET;
833       servaddr.sin_port = htons(UDP_CODE_COMPLETION_LOGGER_PORT);
834       if (inet_pton(AF_INET, UDP_CODE_COMPLETION_LOGGER,
835                     &servaddr.sin_addr) <= 0)
836         break;
837 
838       int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
839       if (sockfd < 0)
840         break;
841 
842       sendto(sockfd, res.data(), res.size(), 0,
843              (struct sockaddr *)&servaddr, sizeof(servaddr));
844       close(sockfd);
845     }
846     while (false);
847   }
848 #endif
849 #endif
850   return Results;
851 }
852 
853 CXCodeCompleteResults *clang_codeCompleteAt(CXTranslationUnit TU,
854                                             const char *complete_filename,
855                                             unsigned complete_line,
856                                             unsigned complete_column,
857                                             struct CXUnsavedFile *unsaved_files,
858                                             unsigned num_unsaved_files,
859                                             unsigned options) {
860   LOG_FUNC_SECTION {
861     *Log << TU << ' '
862          << complete_filename << ':' << complete_line << ':' << complete_column;
863   }
864 
865   if (num_unsaved_files && !unsaved_files)
866     return nullptr;
867 
868   CXCodeCompleteResults *result;
869   auto CodeCompleteAtImpl = [=, &result]() {
870     result = clang_codeCompleteAt_Impl(
871         TU, complete_filename, complete_line, complete_column,
872         llvm::makeArrayRef(unsaved_files, num_unsaved_files), options);
873   };
874 
875   llvm::CrashRecoveryContext CRC;
876 
877   if (!RunSafely(CRC, CodeCompleteAtImpl)) {
878     fprintf(stderr, "libclang: crash detected in code completion\n");
879     cxtu::getASTUnit(TU)->setUnsafeToFree(true);
880     return nullptr;
881   } else if (getenv("LIBCLANG_RESOURCE_USAGE"))
882     PrintLibclangResourceUsage(TU);
883 
884   return result;
885 }
886 
887 unsigned clang_defaultCodeCompleteOptions(void) {
888   return CXCodeComplete_IncludeMacros;
889 }
890 
891 void clang_disposeCodeCompleteResults(CXCodeCompleteResults *ResultsIn) {
892   if (!ResultsIn)
893     return;
894 
895   AllocatedCXCodeCompleteResults *Results
896     = static_cast<AllocatedCXCodeCompleteResults*>(ResultsIn);
897   delete Results;
898 }
899 
900 unsigned
901 clang_codeCompleteGetNumDiagnostics(CXCodeCompleteResults *ResultsIn) {
902   AllocatedCXCodeCompleteResults *Results
903     = static_cast<AllocatedCXCodeCompleteResults*>(ResultsIn);
904   if (!Results)
905     return 0;
906 
907   return Results->Diagnostics.size();
908 }
909 
910 CXDiagnostic
911 clang_codeCompleteGetDiagnostic(CXCodeCompleteResults *ResultsIn,
912                                 unsigned Index) {
913   AllocatedCXCodeCompleteResults *Results
914     = static_cast<AllocatedCXCodeCompleteResults*>(ResultsIn);
915   if (!Results || Index >= Results->Diagnostics.size())
916     return nullptr;
917 
918   CXStoredDiagnostic *Diag = Results->DiagnosticsWrappers[Index];
919   if (!Diag)
920     Results->DiagnosticsWrappers[Index] = Diag =
921         new CXStoredDiagnostic(Results->Diagnostics[Index], Results->LangOpts);
922   return Diag;
923 }
924 
925 unsigned long long
926 clang_codeCompleteGetContexts(CXCodeCompleteResults *ResultsIn) {
927   AllocatedCXCodeCompleteResults *Results
928     = static_cast<AllocatedCXCodeCompleteResults*>(ResultsIn);
929   if (!Results)
930     return 0;
931 
932   return Results->Contexts;
933 }
934 
935 enum CXCursorKind clang_codeCompleteGetContainerKind(
936                                                CXCodeCompleteResults *ResultsIn,
937                                                      unsigned *IsIncomplete) {
938   AllocatedCXCodeCompleteResults *Results =
939     static_cast<AllocatedCXCodeCompleteResults *>(ResultsIn);
940   if (!Results)
941     return CXCursor_InvalidCode;
942 
943   if (IsIncomplete != nullptr) {
944     *IsIncomplete = Results->ContainerIsIncomplete;
945   }
946 
947   return Results->ContainerKind;
948 }
949 
950 CXString clang_codeCompleteGetContainerUSR(CXCodeCompleteResults *ResultsIn) {
951   AllocatedCXCodeCompleteResults *Results =
952     static_cast<AllocatedCXCodeCompleteResults *>(ResultsIn);
953   if (!Results)
954     return cxstring::createEmpty();
955 
956   return cxstring::createRef(Results->ContainerUSR.c_str());
957 }
958 
959 
960 CXString clang_codeCompleteGetObjCSelector(CXCodeCompleteResults *ResultsIn) {
961   AllocatedCXCodeCompleteResults *Results =
962     static_cast<AllocatedCXCodeCompleteResults *>(ResultsIn);
963   if (!Results)
964     return cxstring::createEmpty();
965 
966   return cxstring::createDup(Results->Selector);
967 }
968 
969 /// Simple utility function that appends a \p New string to the given
970 /// \p Old string, using the \p Buffer for storage.
971 ///
972 /// \param Old The string to which we are appending. This parameter will be
973 /// updated to reflect the complete string.
974 ///
975 ///
976 /// \param New The string to append to \p Old.
977 ///
978 /// \param Buffer A buffer that stores the actual, concatenated string. It will
979 /// be used if the old string is already-non-empty.
980 static void AppendToString(StringRef &Old, StringRef New,
981                            SmallString<256> &Buffer) {
982   if (Old.empty()) {
983     Old = New;
984     return;
985   }
986 
987   if (Buffer.empty())
988     Buffer.append(Old.begin(), Old.end());
989   Buffer.append(New.begin(), New.end());
990   Old = Buffer.str();
991 }
992 
993 /// Get the typed-text blocks from the given code-completion string
994 /// and return them as a single string.
995 ///
996 /// \param String The code-completion string whose typed-text blocks will be
997 /// concatenated.
998 ///
999 /// \param Buffer A buffer used for storage of the completed name.
1000 static StringRef GetTypedName(CodeCompletionString *String,
1001                                     SmallString<256> &Buffer) {
1002   StringRef Result;
1003   for (CodeCompletionString::iterator C = String->begin(), CEnd = String->end();
1004        C != CEnd; ++C) {
1005     if (C->Kind == CodeCompletionString::CK_TypedText)
1006       AppendToString(Result, C->Text, Buffer);
1007   }
1008 
1009   return Result;
1010 }
1011 
1012 namespace {
1013   struct OrderCompletionResults {
1014     bool operator()(const CXCompletionResult &XR,
1015                     const CXCompletionResult &YR) const {
1016       CodeCompletionString *X
1017         = (CodeCompletionString *)XR.CompletionString;
1018       CodeCompletionString *Y
1019         = (CodeCompletionString *)YR.CompletionString;
1020 
1021       SmallString<256> XBuffer;
1022       StringRef XText = GetTypedName(X, XBuffer);
1023       SmallString<256> YBuffer;
1024       StringRef YText = GetTypedName(Y, YBuffer);
1025 
1026       if (XText.empty() || YText.empty())
1027         return !XText.empty();
1028 
1029       int result = XText.compare_lower(YText);
1030       if (result < 0)
1031         return true;
1032       if (result > 0)
1033         return false;
1034 
1035       result = XText.compare(YText);
1036       return result < 0;
1037     }
1038   };
1039 }
1040 
1041 void clang_sortCodeCompletionResults(CXCompletionResult *Results,
1042                                      unsigned NumResults) {
1043   std::stable_sort(Results, Results + NumResults, OrderCompletionResults());
1044 }
1045