1 //===--- TokenAnnotator.cpp - Format C++ code -----------------------------===//
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 /// \file
11 /// \brief This file implements a token annotator, i.e. creates
12 /// \c AnnotatedTokens out of \c FormatTokens with required extra information.
13 ///
14 //===----------------------------------------------------------------------===//
15 
16 #include "TokenAnnotator.h"
17 #include "clang/Basic/SourceManager.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/Support/Debug.h"
20 
21 #define DEBUG_TYPE "format-token-annotator"
22 
23 namespace clang {
24 namespace format {
25 
26 namespace {
27 
28 /// \brief A parser that gathers additional information about tokens.
29 ///
30 /// The \c TokenAnnotator tries to match parenthesis and square brakets and
31 /// store a parenthesis levels. It also tries to resolve matching "<" and ">"
32 /// into template parameter lists.
33 class AnnotatingParser {
34 public:
35   AnnotatingParser(const FormatStyle &Style, AnnotatedLine &Line,
36                    const AdditionalKeywords &Keywords)
37       : Style(Style), Line(Line), CurrentToken(Line.First), AutoFound(false),
38         Keywords(Keywords) {
39     Contexts.push_back(Context(tok::unknown, 1, /*IsExpression=*/false));
40     resetTokenMetadata(CurrentToken);
41   }
42 
43 private:
44   bool parseAngle() {
45     if (!CurrentToken || !CurrentToken->Previous)
46       return false;
47     if (NonTemplateLess.count(CurrentToken->Previous))
48       return false;
49 
50     const FormatToken& Previous = *CurrentToken->Previous;
51     if (Previous.Previous) {
52       if (Previous.Previous->Tok.isLiteral())
53         return false;
54       if (Previous.Previous->is(tok::r_paren) && Contexts.size() > 1 &&
55           (!Previous.Previous->MatchingParen ||
56            !Previous.Previous->MatchingParen->is(TT_OverloadedOperatorLParen)))
57         return false;
58     }
59 
60     FormatToken *Left = CurrentToken->Previous;
61     Left->ParentBracket = Contexts.back().ContextKind;
62     ScopedContextCreator ContextCreator(*this, tok::less, 12);
63 
64     // If this angle is in the context of an expression, we need to be more
65     // hesitant to detect it as opening template parameters.
66     bool InExprContext = Contexts.back().IsExpression;
67 
68     Contexts.back().IsExpression = false;
69     // If there's a template keyword before the opening angle bracket, this is a
70     // template parameter, not an argument.
71     Contexts.back().InTemplateArgument =
72         Left->Previous && Left->Previous->Tok.isNot(tok::kw_template);
73 
74     if (Style.Language == FormatStyle::LK_Java &&
75         CurrentToken->is(tok::question))
76       next();
77 
78     while (CurrentToken) {
79       if (CurrentToken->is(tok::greater)) {
80         Left->MatchingParen = CurrentToken;
81         CurrentToken->MatchingParen = Left;
82         CurrentToken->Type = TT_TemplateCloser;
83         next();
84         return true;
85       }
86       if (CurrentToken->is(tok::question) &&
87           Style.Language == FormatStyle::LK_Java) {
88         next();
89         continue;
90       }
91       if (CurrentToken->isOneOf(tok::r_paren, tok::r_square, tok::r_brace) ||
92           (CurrentToken->isOneOf(tok::colon, tok::question) && InExprContext))
93         return false;
94       // If a && or || is found and interpreted as a binary operator, this set
95       // of angles is likely part of something like "a < b && c > d". If the
96       // angles are inside an expression, the ||/&& might also be a binary
97       // operator that was misinterpreted because we are parsing template
98       // parameters.
99       // FIXME: This is getting out of hand, write a decent parser.
100       if (CurrentToken->Previous->isOneOf(tok::pipepipe, tok::ampamp) &&
101           CurrentToken->Previous->is(TT_BinaryOperator) &&
102           Contexts[Contexts.size() - 2].IsExpression &&
103           !Line.startsWith(tok::kw_template))
104         return false;
105       updateParameterCount(Left, CurrentToken);
106       if (!consumeToken())
107         return false;
108     }
109     return false;
110   }
111 
112   bool parseParens(bool LookForDecls = false) {
113     if (!CurrentToken)
114       return false;
115     FormatToken *Left = CurrentToken->Previous;
116     Left->ParentBracket = Contexts.back().ContextKind;
117     ScopedContextCreator ContextCreator(*this, tok::l_paren, 1);
118 
119     // FIXME: This is a bit of a hack. Do better.
120     Contexts.back().ColonIsForRangeExpr =
121         Contexts.size() == 2 && Contexts[0].ColonIsForRangeExpr;
122 
123     bool StartsObjCMethodExpr = false;
124     if (CurrentToken->is(tok::caret)) {
125       // (^ can start a block type.
126       Left->Type = TT_ObjCBlockLParen;
127     } else if (FormatToken *MaybeSel = Left->Previous) {
128       // @selector( starts a selector.
129       if (MaybeSel->isObjCAtKeyword(tok::objc_selector) && MaybeSel->Previous &&
130           MaybeSel->Previous->is(tok::at)) {
131         StartsObjCMethodExpr = true;
132       }
133     }
134 
135     if (Left->is(TT_OverloadedOperatorLParen)) {
136       Contexts.back().IsExpression = false;
137     } else if (Left->Previous &&
138         (Left->Previous->isOneOf(tok::kw_static_assert, tok::kw_decltype,
139                                  tok::kw_if, tok::kw_while, tok::l_paren,
140                                  tok::comma) ||
141          Left->Previous->is(TT_BinaryOperator))) {
142       // static_assert, if and while usually contain expressions.
143       Contexts.back().IsExpression = true;
144     } else if (Style.Language == FormatStyle::LK_JavaScript && Left->Previous &&
145                Left->Previous->is(Keywords.kw_function)) {
146       Contexts.back().IsExpression = false;
147     } else if (Left->Previous && Left->Previous->is(tok::r_square) &&
148                Left->Previous->MatchingParen &&
149                Left->Previous->MatchingParen->is(TT_LambdaLSquare)) {
150       // This is a parameter list of a lambda expression.
151       Contexts.back().IsExpression = false;
152     } else if (Line.InPPDirective &&
153                (!Left->Previous || !Left->Previous->is(tok::identifier))) {
154       Contexts.back().IsExpression = true;
155     } else if (Contexts[Contexts.size() - 2].CaretFound) {
156       // This is the parameter list of an ObjC block.
157       Contexts.back().IsExpression = false;
158     } else if (Left->Previous && Left->Previous->is(tok::kw___attribute)) {
159       Left->Type = TT_AttributeParen;
160     } else if (Left->Previous && Left->Previous->is(TT_ForEachMacro)) {
161       // The first argument to a foreach macro is a declaration.
162       Contexts.back().IsForEachMacro = true;
163       Contexts.back().IsExpression = false;
164     } else if (Left->Previous && Left->Previous->MatchingParen &&
165                Left->Previous->MatchingParen->is(TT_ObjCBlockLParen)) {
166       Contexts.back().IsExpression = false;
167     } else if (!Line.MustBeDeclaration && !Line.InPPDirective) {
168       bool IsForOrCatch =
169           Left->Previous && Left->Previous->isOneOf(tok::kw_for, tok::kw_catch);
170       Contexts.back().IsExpression = !IsForOrCatch;
171     }
172 
173     if (StartsObjCMethodExpr) {
174       Contexts.back().ColonIsObjCMethodExpr = true;
175       Left->Type = TT_ObjCMethodExpr;
176     }
177 
178     bool MightBeFunctionType = CurrentToken->isOneOf(tok::star, tok::amp) &&
179                                !Contexts[Contexts.size() - 2].IsExpression;
180     bool HasMultipleLines = false;
181     bool HasMultipleParametersOnALine = false;
182     bool MightBeObjCForRangeLoop =
183         Left->Previous && Left->Previous->is(tok::kw_for);
184     while (CurrentToken) {
185       // LookForDecls is set when "if (" has been seen. Check for
186       // 'identifier' '*' 'identifier' followed by not '=' -- this
187       // '*' has to be a binary operator but determineStarAmpUsage() will
188       // categorize it as an unary operator, so set the right type here.
189       if (LookForDecls && CurrentToken->Next) {
190         FormatToken *Prev = CurrentToken->getPreviousNonComment();
191         if (Prev) {
192           FormatToken *PrevPrev = Prev->getPreviousNonComment();
193           FormatToken *Next = CurrentToken->Next;
194           if (PrevPrev && PrevPrev->is(tok::identifier) &&
195               Prev->isOneOf(tok::star, tok::amp, tok::ampamp) &&
196               CurrentToken->is(tok::identifier) && Next->isNot(tok::equal)) {
197             Prev->Type = TT_BinaryOperator;
198             LookForDecls = false;
199           }
200         }
201       }
202 
203       if (CurrentToken->Previous->is(TT_PointerOrReference) &&
204           CurrentToken->Previous->Previous->isOneOf(tok::l_paren,
205                                                     tok::coloncolon))
206         MightBeFunctionType = true;
207       if (CurrentToken->Previous->is(TT_BinaryOperator))
208         Contexts.back().IsExpression = true;
209       if (CurrentToken->is(tok::r_paren)) {
210         if (MightBeFunctionType && CurrentToken->Next &&
211             (CurrentToken->Next->is(tok::l_paren) ||
212              (CurrentToken->Next->is(tok::l_square) &&
213               Line.MustBeDeclaration)))
214           Left->Type = TT_FunctionTypeLParen;
215         Left->MatchingParen = CurrentToken;
216         CurrentToken->MatchingParen = Left;
217 
218         if (CurrentToken->Next && CurrentToken->Next->is(tok::l_brace) &&
219             Left->Previous && Left->Previous->is(tok::l_paren)) {
220           // Detect the case where macros are used to generate lambdas or
221           // function bodies, e.g.:
222           //   auto my_lambda = MARCO((Type *type, int i) { .. body .. });
223           for (FormatToken *Tok = Left; Tok != CurrentToken; Tok = Tok->Next) {
224             if (Tok->is(TT_BinaryOperator) &&
225                 Tok->isOneOf(tok::star, tok::amp, tok::ampamp))
226               Tok->Type = TT_PointerOrReference;
227           }
228         }
229 
230         if (StartsObjCMethodExpr) {
231           CurrentToken->Type = TT_ObjCMethodExpr;
232           if (Contexts.back().FirstObjCSelectorName) {
233             Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
234                 Contexts.back().LongestObjCSelectorName;
235           }
236         }
237 
238         if (Left->is(TT_AttributeParen))
239           CurrentToken->Type = TT_AttributeParen;
240         if (Left->Previous && Left->Previous->is(TT_JavaAnnotation))
241           CurrentToken->Type = TT_JavaAnnotation;
242         if (Left->Previous && Left->Previous->is(TT_LeadingJavaAnnotation))
243           CurrentToken->Type = TT_LeadingJavaAnnotation;
244 
245         if (!HasMultipleLines)
246           Left->PackingKind = PPK_Inconclusive;
247         else if (HasMultipleParametersOnALine)
248           Left->PackingKind = PPK_BinPacked;
249         else
250           Left->PackingKind = PPK_OnePerLine;
251 
252         next();
253         return true;
254       }
255       if (CurrentToken->isOneOf(tok::r_square, tok::r_brace))
256         return false;
257 
258       if (CurrentToken->is(tok::l_brace))
259         Left->Type = TT_Unknown; // Not TT_ObjCBlockLParen
260       if (CurrentToken->is(tok::comma) && CurrentToken->Next &&
261           !CurrentToken->Next->HasUnescapedNewline &&
262           !CurrentToken->Next->isTrailingComment())
263         HasMultipleParametersOnALine = true;
264       if (CurrentToken->isOneOf(tok::kw_const, tok::kw_auto) ||
265           CurrentToken->isSimpleTypeSpecifier())
266         Contexts.back().IsExpression = false;
267       if (CurrentToken->isOneOf(tok::semi, tok::colon))
268         MightBeObjCForRangeLoop = false;
269       if (MightBeObjCForRangeLoop && CurrentToken->is(Keywords.kw_in))
270         CurrentToken->Type = TT_ObjCForIn;
271       // When we discover a 'new', we set CanBeExpression to 'false' in order to
272       // parse the type correctly. Reset that after a comma.
273       if (CurrentToken->is(tok::comma))
274         Contexts.back().CanBeExpression = true;
275 
276       FormatToken *Tok = CurrentToken;
277       if (!consumeToken())
278         return false;
279       updateParameterCount(Left, Tok);
280       if (CurrentToken && CurrentToken->HasUnescapedNewline)
281         HasMultipleLines = true;
282     }
283     return false;
284   }
285 
286   bool parseSquare() {
287     if (!CurrentToken)
288       return false;
289 
290     // A '[' could be an index subscript (after an identifier or after
291     // ')' or ']'), it could be the start of an Objective-C method
292     // expression, or it could the start of an Objective-C array literal.
293     FormatToken *Left = CurrentToken->Previous;
294     Left->ParentBracket = Contexts.back().ContextKind;
295     FormatToken *Parent = Left->getPreviousNonComment();
296     bool StartsObjCMethodExpr =
297         Style.Language == FormatStyle::LK_Cpp &&
298         Contexts.back().CanBeExpression && Left->isNot(TT_LambdaLSquare) &&
299         CurrentToken->isNot(tok::l_brace) &&
300         (!Parent ||
301          Parent->isOneOf(tok::colon, tok::l_square, tok::l_paren,
302                          tok::kw_return, tok::kw_throw) ||
303          Parent->isUnaryOperator() ||
304          Parent->isOneOf(TT_ObjCForIn, TT_CastRParen) ||
305          getBinOpPrecedence(Parent->Tok.getKind(), true, true) > prec::Unknown);
306     bool ColonFound = false;
307 
308     unsigned BindingIncrease = 1;
309     if (Left->is(TT_Unknown)) {
310       if (StartsObjCMethodExpr) {
311         Left->Type = TT_ObjCMethodExpr;
312       } else if (Style.Language == FormatStyle::LK_JavaScript && Parent &&
313                  Contexts.back().ContextKind == tok::l_brace &&
314                  Parent->isOneOf(tok::l_brace, tok::comma)) {
315         Left->Type = TT_JsComputedPropertyName;
316       } else if (Style.Language == FormatStyle::LK_Proto ||
317                  (Parent &&
318                   Parent->isOneOf(TT_BinaryOperator, tok::at, tok::comma,
319                                   tok::l_paren, tok::l_square, tok::question,
320                                   tok::colon, tok::kw_return,
321                                   // Should only be relevant to JavaScript:
322                                   tok::kw_default))) {
323         Left->Type = TT_ArrayInitializerLSquare;
324       } else {
325         BindingIncrease = 10;
326         Left->Type = TT_ArraySubscriptLSquare;
327       }
328     }
329 
330     ScopedContextCreator ContextCreator(*this, tok::l_square, BindingIncrease);
331     Contexts.back().IsExpression = true;
332     Contexts.back().ColonIsObjCMethodExpr = StartsObjCMethodExpr;
333 
334     while (CurrentToken) {
335       if (CurrentToken->is(tok::r_square)) {
336         if (CurrentToken->Next && CurrentToken->Next->is(tok::l_paren) &&
337             Left->is(TT_ObjCMethodExpr)) {
338           // An ObjC method call is rarely followed by an open parenthesis.
339           // FIXME: Do we incorrectly label ":" with this?
340           StartsObjCMethodExpr = false;
341           Left->Type = TT_Unknown;
342         }
343         if (StartsObjCMethodExpr && CurrentToken->Previous != Left) {
344           CurrentToken->Type = TT_ObjCMethodExpr;
345           // determineStarAmpUsage() thinks that '*' '[' is allocating an
346           // array of pointers, but if '[' starts a selector then '*' is a
347           // binary operator.
348           if (Parent && Parent->is(TT_PointerOrReference))
349             Parent->Type = TT_BinaryOperator;
350         }
351         Left->MatchingParen = CurrentToken;
352         CurrentToken->MatchingParen = Left;
353         if (Contexts.back().FirstObjCSelectorName) {
354           Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
355               Contexts.back().LongestObjCSelectorName;
356           if (Left->BlockParameterCount > 1)
357             Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName = 0;
358         }
359         next();
360         return true;
361       }
362       if (CurrentToken->isOneOf(tok::r_paren, tok::r_brace))
363         return false;
364       if (CurrentToken->is(tok::colon)) {
365         if (Left->is(TT_ArraySubscriptLSquare)) {
366           Left->Type = TT_ObjCMethodExpr;
367           StartsObjCMethodExpr = true;
368           Contexts.back().ColonIsObjCMethodExpr = true;
369           if (Parent && Parent->is(tok::r_paren))
370             Parent->Type = TT_CastRParen;
371         }
372         ColonFound = true;
373       }
374       if (CurrentToken->is(tok::comma) && Left->is(TT_ObjCMethodExpr) &&
375           !ColonFound)
376         Left->Type = TT_ArrayInitializerLSquare;
377       FormatToken *Tok = CurrentToken;
378       if (!consumeToken())
379         return false;
380       updateParameterCount(Left, Tok);
381     }
382     return false;
383   }
384 
385   bool parseBrace() {
386     if (CurrentToken) {
387       FormatToken *Left = CurrentToken->Previous;
388       Left->ParentBracket = Contexts.back().ContextKind;
389 
390       if (Contexts.back().CaretFound)
391         Left->Type = TT_ObjCBlockLBrace;
392       Contexts.back().CaretFound = false;
393 
394       ScopedContextCreator ContextCreator(*this, tok::l_brace, 1);
395       Contexts.back().ColonIsDictLiteral = true;
396       if (Left->BlockKind == BK_BracedInit)
397         Contexts.back().IsExpression = true;
398 
399       while (CurrentToken) {
400         if (CurrentToken->is(tok::r_brace)) {
401           Left->MatchingParen = CurrentToken;
402           CurrentToken->MatchingParen = Left;
403           next();
404           return true;
405         }
406         if (CurrentToken->isOneOf(tok::r_paren, tok::r_square))
407           return false;
408         updateParameterCount(Left, CurrentToken);
409         if (CurrentToken->isOneOf(tok::colon, tok::l_brace)) {
410           FormatToken *Previous = CurrentToken->getPreviousNonComment();
411           if (((CurrentToken->is(tok::colon) &&
412                 (!Contexts.back().ColonIsDictLiteral ||
413                  Style.Language != FormatStyle::LK_Cpp)) ||
414                Style.Language == FormatStyle::LK_Proto) &&
415               (Previous->Tok.getIdentifierInfo() ||
416                Previous->is(tok::string_literal)))
417             Previous->Type = TT_SelectorName;
418           if (CurrentToken->is(tok::colon) ||
419               Style.Language == FormatStyle::LK_JavaScript)
420             Left->Type = TT_DictLiteral;
421         }
422         if (!consumeToken())
423           return false;
424       }
425     }
426     return true;
427   }
428 
429   void updateParameterCount(FormatToken *Left, FormatToken *Current) {
430     if (Current->is(tok::l_brace) && Current->BlockKind == BK_Block)
431       ++Left->BlockParameterCount;
432     if (Current->is(tok::comma)) {
433       ++Left->ParameterCount;
434       if (!Left->Role)
435         Left->Role.reset(new CommaSeparatedList(Style));
436       Left->Role->CommaFound(Current);
437     } else if (Left->ParameterCount == 0 && Current->isNot(tok::comment)) {
438       Left->ParameterCount = 1;
439     }
440   }
441 
442   bool parseConditional() {
443     while (CurrentToken) {
444       if (CurrentToken->is(tok::colon)) {
445         CurrentToken->Type = TT_ConditionalExpr;
446         next();
447         return true;
448       }
449       if (!consumeToken())
450         return false;
451     }
452     return false;
453   }
454 
455   bool parseTemplateDeclaration() {
456     if (CurrentToken && CurrentToken->is(tok::less)) {
457       CurrentToken->Type = TT_TemplateOpener;
458       next();
459       if (!parseAngle())
460         return false;
461       if (CurrentToken)
462         CurrentToken->Previous->ClosesTemplateDeclaration = true;
463       return true;
464     }
465     return false;
466   }
467 
468   bool consumeToken() {
469     FormatToken *Tok = CurrentToken;
470     next();
471     switch (Tok->Tok.getKind()) {
472     case tok::plus:
473     case tok::minus:
474       if (!Tok->Previous && Line.MustBeDeclaration)
475         Tok->Type = TT_ObjCMethodSpecifier;
476       break;
477     case tok::colon:
478       if (!Tok->Previous)
479         return false;
480       // Colons from ?: are handled in parseConditional().
481       if (Style.Language == FormatStyle::LK_JavaScript) {
482         if (Contexts.back().ColonIsForRangeExpr || // colon in for loop
483             (Contexts.size() == 1 &&               // switch/case labels
484              !Line.First->isOneOf(tok::kw_enum, tok::kw_case)) ||
485             Contexts.back().ContextKind == tok::l_paren ||  // function params
486             Contexts.back().ContextKind == tok::l_square || // array type
487             (Contexts.size() == 1 &&
488              Line.MustBeDeclaration)) { // method/property declaration
489           Tok->Type = TT_JsTypeColon;
490           break;
491         }
492       }
493       if (Contexts.back().ColonIsDictLiteral ||
494           Style.Language == FormatStyle::LK_Proto) {
495         Tok->Type = TT_DictLiteral;
496       } else if (Contexts.back().ColonIsObjCMethodExpr ||
497                  Line.startsWith(TT_ObjCMethodSpecifier)) {
498         Tok->Type = TT_ObjCMethodExpr;
499         Tok->Previous->Type = TT_SelectorName;
500         if (Tok->Previous->ColumnWidth >
501             Contexts.back().LongestObjCSelectorName)
502           Contexts.back().LongestObjCSelectorName = Tok->Previous->ColumnWidth;
503         if (!Contexts.back().FirstObjCSelectorName)
504           Contexts.back().FirstObjCSelectorName = Tok->Previous;
505       } else if (Contexts.back().ColonIsForRangeExpr) {
506         Tok->Type = TT_RangeBasedForLoopColon;
507       } else if (CurrentToken && CurrentToken->is(tok::numeric_constant)) {
508         Tok->Type = TT_BitFieldColon;
509       } else if (Contexts.size() == 1 &&
510                  !Line.First->isOneOf(tok::kw_enum, tok::kw_case)) {
511         if (Tok->Previous->isOneOf(tok::r_paren, tok::kw_noexcept))
512           Tok->Type = TT_CtorInitializerColon;
513         else
514           Tok->Type = TT_InheritanceColon;
515       } else if (Tok->Previous->is(tok::identifier) && Tok->Next &&
516                  Tok->Next->isOneOf(tok::r_paren, tok::comma)) {
517         // This handles a special macro in ObjC code where selectors including
518         // the colon are passed as macro arguments.
519         Tok->Type = TT_ObjCMethodExpr;
520       } else if (Contexts.back().ContextKind == tok::l_paren) {
521         Tok->Type = TT_InlineASMColon;
522       }
523       break;
524     case tok::pipe:
525     case tok::amp:
526       // | and & in declarations/type expressions represent union and
527       // intersection types, respectively.
528       if (Style.Language == FormatStyle::LK_JavaScript &&
529           !Contexts.back().IsExpression)
530         Tok->Type = TT_JsTypeOperator;
531       break;
532     case tok::kw_if:
533     case tok::kw_while:
534       if (CurrentToken && CurrentToken->is(tok::l_paren)) {
535         next();
536         if (!parseParens(/*LookForDecls=*/true))
537           return false;
538       }
539       break;
540     case tok::kw_for:
541       Contexts.back().ColonIsForRangeExpr = true;
542       next();
543       if (!parseParens())
544         return false;
545       break;
546     case tok::l_paren:
547       // When faced with 'operator()()', the kw_operator handler incorrectly
548       // marks the first l_paren as a OverloadedOperatorLParen. Here, we make
549       // the first two parens OverloadedOperators and the second l_paren an
550       // OverloadedOperatorLParen.
551       if (Tok->Previous &&
552           Tok->Previous->is(tok::r_paren) &&
553           Tok->Previous->MatchingParen &&
554           Tok->Previous->MatchingParen->is(TT_OverloadedOperatorLParen)) {
555         Tok->Previous->Type = TT_OverloadedOperator;
556         Tok->Previous->MatchingParen->Type = TT_OverloadedOperator;
557         Tok->Type = TT_OverloadedOperatorLParen;
558       }
559 
560       if (!parseParens())
561         return false;
562       if (Line.MustBeDeclaration && Contexts.size() == 1 &&
563           !Contexts.back().IsExpression && !Line.startsWith(TT_ObjCProperty) &&
564           (!Tok->Previous ||
565            !Tok->Previous->isOneOf(tok::kw_decltype, tok::kw___attribute,
566                                    TT_LeadingJavaAnnotation)))
567         Line.MightBeFunctionDecl = true;
568       break;
569     case tok::l_square:
570       if (!parseSquare())
571         return false;
572       break;
573     case tok::l_brace:
574       if (!parseBrace())
575         return false;
576       break;
577     case tok::less:
578       if (parseAngle()) {
579         Tok->Type = TT_TemplateOpener;
580       } else {
581         Tok->Type = TT_BinaryOperator;
582         NonTemplateLess.insert(Tok);
583         CurrentToken = Tok;
584         next();
585       }
586       break;
587     case tok::r_paren:
588     case tok::r_square:
589       return false;
590     case tok::r_brace:
591       // Lines can start with '}'.
592       if (Tok->Previous)
593         return false;
594       break;
595     case tok::greater:
596       Tok->Type = TT_BinaryOperator;
597       break;
598     case tok::kw_operator:
599       while (CurrentToken &&
600              !CurrentToken->isOneOf(tok::l_paren, tok::semi, tok::r_paren)) {
601         if (CurrentToken->isOneOf(tok::star, tok::amp))
602           CurrentToken->Type = TT_PointerOrReference;
603         consumeToken();
604         if (CurrentToken &&
605             CurrentToken->Previous->isOneOf(TT_BinaryOperator, tok::comma))
606           CurrentToken->Previous->Type = TT_OverloadedOperator;
607       }
608       if (CurrentToken) {
609         CurrentToken->Type = TT_OverloadedOperatorLParen;
610         if (CurrentToken->Previous->is(TT_BinaryOperator))
611           CurrentToken->Previous->Type = TT_OverloadedOperator;
612       }
613       break;
614     case tok::question:
615       if (Style.Language == FormatStyle::LK_JavaScript && Tok->Next &&
616           Tok->Next->isOneOf(tok::semi, tok::comma, tok::colon, tok::r_paren,
617                              tok::r_brace)) {
618         // Question marks before semicolons, colons, etc. indicate optional
619         // types (fields, parameters), e.g.
620         //   function(x?: string, y?) {...}
621         //   class X { y?; }
622         Tok->Type = TT_JsTypeOptionalQuestion;
623         break;
624       }
625       // Declarations cannot be conditional expressions, this can only be part
626       // of a type declaration.
627       if (Line.MustBeDeclaration &&
628           Style.Language == FormatStyle::LK_JavaScript)
629         break;
630       parseConditional();
631       break;
632     case tok::kw_template:
633       parseTemplateDeclaration();
634       break;
635     case tok::comma:
636       if (Contexts.back().InCtorInitializer)
637         Tok->Type = TT_CtorInitializerComma;
638       else if (Contexts.back().FirstStartOfName &&
639                (Contexts.size() == 1 || Line.startsWith(tok::kw_for))) {
640         Contexts.back().FirstStartOfName->PartOfMultiVariableDeclStmt = true;
641         Line.IsMultiVariableDeclStmt = true;
642       }
643       if (Contexts.back().IsForEachMacro)
644         Contexts.back().IsExpression = true;
645       break;
646     default:
647       break;
648     }
649     return true;
650   }
651 
652   void parseIncludeDirective() {
653     if (CurrentToken && CurrentToken->is(tok::less)) {
654       next();
655       while (CurrentToken) {
656         if (CurrentToken->isNot(tok::comment) || CurrentToken->Next)
657           CurrentToken->Type = TT_ImplicitStringLiteral;
658         next();
659       }
660     }
661   }
662 
663   void parseWarningOrError() {
664     next();
665     // We still want to format the whitespace left of the first token of the
666     // warning or error.
667     next();
668     while (CurrentToken) {
669       CurrentToken->Type = TT_ImplicitStringLiteral;
670       next();
671     }
672   }
673 
674   void parsePragma() {
675     next(); // Consume "pragma".
676     if (CurrentToken &&
677         CurrentToken->isOneOf(Keywords.kw_mark, Keywords.kw_option)) {
678       bool IsMark = CurrentToken->is(Keywords.kw_mark);
679       next(); // Consume "mark".
680       next(); // Consume first token (so we fix leading whitespace).
681       while (CurrentToken) {
682         if (IsMark || CurrentToken->Previous->is(TT_BinaryOperator))
683           CurrentToken->Type = TT_ImplicitStringLiteral;
684         next();
685       }
686     }
687   }
688 
689   LineType parsePreprocessorDirective() {
690     LineType Type = LT_PreprocessorDirective;
691     next();
692     if (!CurrentToken)
693       return Type;
694     if (CurrentToken->Tok.is(tok::numeric_constant)) {
695       CurrentToken->SpacesRequiredBefore = 1;
696       return Type;
697     }
698     // Hashes in the middle of a line can lead to any strange token
699     // sequence.
700     if (!CurrentToken->Tok.getIdentifierInfo())
701       return Type;
702     switch (CurrentToken->Tok.getIdentifierInfo()->getPPKeywordID()) {
703     case tok::pp_include:
704     case tok::pp_include_next:
705     case tok::pp_import:
706       next();
707       parseIncludeDirective();
708       Type = LT_ImportStatement;
709       break;
710     case tok::pp_error:
711     case tok::pp_warning:
712       parseWarningOrError();
713       break;
714     case tok::pp_pragma:
715       parsePragma();
716       break;
717     case tok::pp_if:
718     case tok::pp_elif:
719       Contexts.back().IsExpression = true;
720       parseLine();
721       break;
722     default:
723       break;
724     }
725     while (CurrentToken)
726       next();
727     return Type;
728   }
729 
730 public:
731   LineType parseLine() {
732     NonTemplateLess.clear();
733     if (CurrentToken->is(tok::hash))
734       return parsePreprocessorDirective();
735 
736     // Directly allow to 'import <string-literal>' to support protocol buffer
737     // definitions (code.google.com/p/protobuf) or missing "#" (either way we
738     // should not break the line).
739     IdentifierInfo *Info = CurrentToken->Tok.getIdentifierInfo();
740     if ((Style.Language == FormatStyle::LK_Java &&
741          CurrentToken->is(Keywords.kw_package)) ||
742         (Info && Info->getPPKeywordID() == tok::pp_import &&
743          CurrentToken->Next &&
744          CurrentToken->Next->isOneOf(tok::string_literal, tok::identifier,
745                                      tok::kw_static))) {
746       next();
747       parseIncludeDirective();
748       return LT_ImportStatement;
749     }
750 
751     // If this line starts and ends in '<' and '>', respectively, it is likely
752     // part of "#define <a/b.h>".
753     if (CurrentToken->is(tok::less) && Line.Last->is(tok::greater)) {
754       parseIncludeDirective();
755       return LT_ImportStatement;
756     }
757 
758     // In .proto files, top-level options are very similar to import statements
759     // and should not be line-wrapped.
760     if (Style.Language == FormatStyle::LK_Proto && Line.Level == 0 &&
761         CurrentToken->is(Keywords.kw_option)) {
762       next();
763       if (CurrentToken && CurrentToken->is(tok::identifier))
764         return LT_ImportStatement;
765     }
766 
767     // import {...} from '...';
768     if (Style.Language == FormatStyle::LK_JavaScript &&
769         CurrentToken->is(Keywords.kw_import))
770       return LT_ImportStatement;
771 
772     bool KeywordVirtualFound = false;
773     bool ImportStatement = false;
774     while (CurrentToken) {
775       if (CurrentToken->is(tok::kw_virtual))
776         KeywordVirtualFound = true;
777       if (Style.Language == FormatStyle::LK_JavaScript) {
778         // export {...} from '...';
779         // An export followed by "from 'some string';" is a re-export from
780         // another module identified by a URI and is treated as a
781         // LT_ImportStatement (i.e. prevent wraps on it for long URIs).
782         // Just "export {...};" or "export class ..." should not be treated as
783         // an import in this sense.
784         if (Line.First->is(tok::kw_export) &&
785             CurrentToken->is(Keywords.kw_from) && CurrentToken->Next &&
786             CurrentToken->Next->isStringLiteral())
787           ImportStatement = true;
788         if (isClosureImportStatement(*CurrentToken))
789           ImportStatement = true;
790       }
791       if (!consumeToken())
792         return LT_Invalid;
793     }
794     if (KeywordVirtualFound)
795       return LT_VirtualFunctionDecl;
796     if (ImportStatement)
797       return LT_ImportStatement;
798 
799     if (Line.startsWith(TT_ObjCMethodSpecifier)) {
800       if (Contexts.back().FirstObjCSelectorName)
801         Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
802             Contexts.back().LongestObjCSelectorName;
803       return LT_ObjCMethodDecl;
804     }
805 
806     return LT_Other;
807   }
808 
809 private:
810   bool isClosureImportStatement(const FormatToken &Tok) {
811     // FIXME: Closure-library specific stuff should not be hard-coded but be
812     // configurable.
813     return Tok.TokenText == "goog" && Tok.Next && Tok.Next->is(tok::period) &&
814            Tok.Next->Next && (Tok.Next->Next->TokenText == "module" ||
815                               Tok.Next->Next->TokenText == "provide" ||
816                               Tok.Next->Next->TokenText == "require" ||
817                               Tok.Next->Next->TokenText == "setTestOnly" ||
818                               Tok.Next->Next->TokenText == "forwardDeclare") &&
819            Tok.Next->Next->Next && Tok.Next->Next->Next->is(tok::l_paren);
820   }
821 
822   void resetTokenMetadata(FormatToken *Token) {
823     if (!Token)
824       return;
825 
826     // Reset token type in case we have already looked at it and then
827     // recovered from an error (e.g. failure to find the matching >).
828     if (!CurrentToken->isOneOf(TT_LambdaLSquare, TT_ForEachMacro,
829                                TT_FunctionLBrace, TT_ImplicitStringLiteral,
830                                TT_InlineASMBrace, TT_JsFatArrow, TT_LambdaArrow,
831                                TT_RegexLiteral))
832       CurrentToken->Type = TT_Unknown;
833     CurrentToken->Role.reset();
834     CurrentToken->MatchingParen = nullptr;
835     CurrentToken->FakeLParens.clear();
836     CurrentToken->FakeRParens = 0;
837   }
838 
839   void next() {
840     if (CurrentToken) {
841       CurrentToken->NestingLevel = Contexts.size() - 1;
842       CurrentToken->BindingStrength = Contexts.back().BindingStrength;
843       modifyContext(*CurrentToken);
844       determineTokenType(*CurrentToken);
845       CurrentToken = CurrentToken->Next;
846     }
847 
848     resetTokenMetadata(CurrentToken);
849   }
850 
851   /// \brief A struct to hold information valid in a specific context, e.g.
852   /// a pair of parenthesis.
853   struct Context {
854     Context(tok::TokenKind ContextKind, unsigned BindingStrength,
855             bool IsExpression)
856         : ContextKind(ContextKind), BindingStrength(BindingStrength),
857           IsExpression(IsExpression) {}
858 
859     tok::TokenKind ContextKind;
860     unsigned BindingStrength;
861     bool IsExpression;
862     unsigned LongestObjCSelectorName = 0;
863     bool ColonIsForRangeExpr = false;
864     bool ColonIsDictLiteral = false;
865     bool ColonIsObjCMethodExpr = false;
866     FormatToken *FirstObjCSelectorName = nullptr;
867     FormatToken *FirstStartOfName = nullptr;
868     bool CanBeExpression = true;
869     bool InTemplateArgument = false;
870     bool InCtorInitializer = false;
871     bool CaretFound = false;
872     bool IsForEachMacro = false;
873   };
874 
875   /// \brief Puts a new \c Context onto the stack \c Contexts for the lifetime
876   /// of each instance.
877   struct ScopedContextCreator {
878     AnnotatingParser &P;
879 
880     ScopedContextCreator(AnnotatingParser &P, tok::TokenKind ContextKind,
881                          unsigned Increase)
882         : P(P) {
883       P.Contexts.push_back(Context(ContextKind,
884                                    P.Contexts.back().BindingStrength + Increase,
885                                    P.Contexts.back().IsExpression));
886     }
887 
888     ~ScopedContextCreator() { P.Contexts.pop_back(); }
889   };
890 
891   void modifyContext(const FormatToken &Current) {
892     if (Current.getPrecedence() == prec::Assignment &&
893         !Line.First->isOneOf(tok::kw_template, tok::kw_using, tok::kw_return) &&
894         (!Current.Previous || Current.Previous->isNot(tok::kw_operator))) {
895       Contexts.back().IsExpression = true;
896       if (!Line.startsWith(TT_UnaryOperator)) {
897         for (FormatToken *Previous = Current.Previous;
898              Previous && Previous->Previous &&
899              !Previous->Previous->isOneOf(tok::comma, tok::semi);
900              Previous = Previous->Previous) {
901           if (Previous->isOneOf(tok::r_square, tok::r_paren)) {
902             Previous = Previous->MatchingParen;
903             if (!Previous)
904               break;
905           }
906           if (Previous->opensScope())
907             break;
908           if (Previous->isOneOf(TT_BinaryOperator, TT_UnaryOperator) &&
909               Previous->isOneOf(tok::star, tok::amp, tok::ampamp) &&
910               Previous->Previous && Previous->Previous->isNot(tok::equal))
911             Previous->Type = TT_PointerOrReference;
912         }
913       }
914     } else if (Current.is(tok::lessless) &&
915                (!Current.Previous || !Current.Previous->is(tok::kw_operator))) {
916       Contexts.back().IsExpression = true;
917     } else if (Current.isOneOf(tok::kw_return, tok::kw_throw)) {
918       Contexts.back().IsExpression = true;
919     } else if (Current.is(TT_TrailingReturnArrow)) {
920       Contexts.back().IsExpression = false;
921     } else if (Current.is(TT_LambdaArrow) || Current.is(Keywords.kw_assert)) {
922       Contexts.back().IsExpression = Style.Language == FormatStyle::LK_Java;
923     } else if (Current.isOneOf(tok::r_paren, tok::greater, tok::comma)) {
924       for (FormatToken *Previous = Current.Previous;
925            Previous && Previous->isOneOf(tok::star, tok::amp);
926            Previous = Previous->Previous)
927         Previous->Type = TT_PointerOrReference;
928       if (Line.MustBeDeclaration && !Contexts.front().InCtorInitializer)
929         Contexts.back().IsExpression = false;
930     } else if (Current.Previous &&
931                Current.Previous->is(TT_CtorInitializerColon)) {
932       Contexts.back().IsExpression = true;
933       Contexts.back().InCtorInitializer = true;
934     } else if (Current.is(tok::kw_new)) {
935       Contexts.back().CanBeExpression = false;
936     } else if (Current.isOneOf(tok::semi, tok::exclaim)) {
937       // This should be the condition or increment in a for-loop.
938       Contexts.back().IsExpression = true;
939     }
940   }
941 
942   void determineTokenType(FormatToken &Current) {
943     if (!Current.is(TT_Unknown))
944       // The token type is already known.
945       return;
946 
947     // Line.MightBeFunctionDecl can only be true after the parentheses of a
948     // function declaration have been found. In this case, 'Current' is a
949     // trailing token of this declaration and thus cannot be a name.
950     if (Current.is(Keywords.kw_instanceof)) {
951       Current.Type = TT_BinaryOperator;
952     } else if (isStartOfName(Current) &&
953                (!Line.MightBeFunctionDecl || Current.NestingLevel != 0)) {
954       Contexts.back().FirstStartOfName = &Current;
955       Current.Type = TT_StartOfName;
956     } else if (Current.isOneOf(tok::kw_auto, tok::kw___auto_type)) {
957       AutoFound = true;
958     } else if (Current.is(tok::arrow) &&
959                Style.Language == FormatStyle::LK_Java) {
960       Current.Type = TT_LambdaArrow;
961     } else if (Current.is(tok::arrow) && AutoFound && Line.MustBeDeclaration &&
962                Current.NestingLevel == 0) {
963       Current.Type = TT_TrailingReturnArrow;
964     } else if (Current.isOneOf(tok::star, tok::amp, tok::ampamp)) {
965       Current.Type =
966           determineStarAmpUsage(Current, Contexts.back().CanBeExpression &&
967                                              Contexts.back().IsExpression,
968                                 Contexts.back().InTemplateArgument);
969     } else if (Current.isOneOf(tok::minus, tok::plus, tok::caret)) {
970       Current.Type = determinePlusMinusCaretUsage(Current);
971       if (Current.is(TT_UnaryOperator) && Current.is(tok::caret))
972         Contexts.back().CaretFound = true;
973     } else if (Current.isOneOf(tok::minusminus, tok::plusplus)) {
974       Current.Type = determineIncrementUsage(Current);
975     } else if (Current.isOneOf(tok::exclaim, tok::tilde)) {
976       Current.Type = TT_UnaryOperator;
977     } else if (Current.is(tok::question)) {
978       if (Style.Language == FormatStyle::LK_JavaScript &&
979           Line.MustBeDeclaration) {
980         // In JavaScript, `interface X { foo?(): bar; }` is an optional method
981         // on the interface, not a ternary expression.
982         Current.Type = TT_JsTypeOptionalQuestion;
983       } else {
984         Current.Type = TT_ConditionalExpr;
985       }
986     } else if (Current.isBinaryOperator() &&
987                (!Current.Previous || Current.Previous->isNot(tok::l_square))) {
988       Current.Type = TT_BinaryOperator;
989     } else if (Current.is(tok::comment)) {
990       if (Current.TokenText.startswith("/*")) {
991         if (Current.TokenText.endswith("*/"))
992           Current.Type = TT_BlockComment;
993         else
994           // The lexer has for some reason determined a comment here. But we
995           // cannot really handle it, if it isn't properly terminated.
996           Current.Tok.setKind(tok::unknown);
997       } else {
998         Current.Type = TT_LineComment;
999       }
1000     } else if (Current.is(tok::r_paren)) {
1001       if (rParenEndsCast(Current))
1002         Current.Type = TT_CastRParen;
1003       if (Current.MatchingParen && Current.Next &&
1004           !Current.Next->isBinaryOperator() &&
1005           !Current.Next->isOneOf(tok::semi, tok::colon, tok::l_brace,
1006                                  tok::period, tok::arrow, tok::coloncolon))
1007         if (FormatToken *BeforeParen = Current.MatchingParen->Previous)
1008           if (BeforeParen->is(tok::identifier) &&
1009               BeforeParen->TokenText == BeforeParen->TokenText.upper() &&
1010               (!BeforeParen->Previous ||
1011                BeforeParen->Previous->ClosesTemplateDeclaration))
1012             Current.Type = TT_FunctionAnnotationRParen;
1013     } else if (Current.is(tok::at) && Current.Next) {
1014       if (Current.Next->isStringLiteral()) {
1015         Current.Type = TT_ObjCStringLiteral;
1016       } else {
1017         switch (Current.Next->Tok.getObjCKeywordID()) {
1018         case tok::objc_interface:
1019         case tok::objc_implementation:
1020         case tok::objc_protocol:
1021           Current.Type = TT_ObjCDecl;
1022           break;
1023         case tok::objc_property:
1024           Current.Type = TT_ObjCProperty;
1025           break;
1026         default:
1027           break;
1028         }
1029       }
1030     } else if (Current.is(tok::period)) {
1031       FormatToken *PreviousNoComment = Current.getPreviousNonComment();
1032       if (PreviousNoComment &&
1033           PreviousNoComment->isOneOf(tok::comma, tok::l_brace))
1034         Current.Type = TT_DesignatedInitializerPeriod;
1035       else if (Style.Language == FormatStyle::LK_Java && Current.Previous &&
1036                Current.Previous->isOneOf(TT_JavaAnnotation,
1037                                          TT_LeadingJavaAnnotation)) {
1038         Current.Type = Current.Previous->Type;
1039       }
1040     } else if (Current.isOneOf(tok::identifier, tok::kw_const) &&
1041                Current.Previous &&
1042                !Current.Previous->isOneOf(tok::equal, tok::at) &&
1043                Line.MightBeFunctionDecl && Contexts.size() == 1) {
1044       // Line.MightBeFunctionDecl can only be true after the parentheses of a
1045       // function declaration have been found.
1046       Current.Type = TT_TrailingAnnotation;
1047     } else if ((Style.Language == FormatStyle::LK_Java ||
1048                 Style.Language == FormatStyle::LK_JavaScript) &&
1049                Current.Previous) {
1050       if (Current.Previous->is(tok::at) &&
1051           Current.isNot(Keywords.kw_interface)) {
1052         const FormatToken &AtToken = *Current.Previous;
1053         const FormatToken *Previous = AtToken.getPreviousNonComment();
1054         if (!Previous || Previous->is(TT_LeadingJavaAnnotation))
1055           Current.Type = TT_LeadingJavaAnnotation;
1056         else
1057           Current.Type = TT_JavaAnnotation;
1058       } else if (Current.Previous->is(tok::period) &&
1059                  Current.Previous->isOneOf(TT_JavaAnnotation,
1060                                            TT_LeadingJavaAnnotation)) {
1061         Current.Type = Current.Previous->Type;
1062       }
1063     }
1064   }
1065 
1066   /// \brief Take a guess at whether \p Tok starts a name of a function or
1067   /// variable declaration.
1068   ///
1069   /// This is a heuristic based on whether \p Tok is an identifier following
1070   /// something that is likely a type.
1071   bool isStartOfName(const FormatToken &Tok) {
1072     if (Tok.isNot(tok::identifier) || !Tok.Previous)
1073       return false;
1074 
1075     if (Tok.Previous->isOneOf(TT_LeadingJavaAnnotation, Keywords.kw_instanceof))
1076       return false;
1077     if (Style.Language == FormatStyle::LK_JavaScript &&
1078         Tok.Previous->is(Keywords.kw_in))
1079       return false;
1080 
1081     // Skip "const" as it does not have an influence on whether this is a name.
1082     FormatToken *PreviousNotConst = Tok.Previous;
1083     while (PreviousNotConst && PreviousNotConst->is(tok::kw_const))
1084       PreviousNotConst = PreviousNotConst->Previous;
1085 
1086     if (!PreviousNotConst)
1087       return false;
1088 
1089     bool IsPPKeyword = PreviousNotConst->is(tok::identifier) &&
1090                        PreviousNotConst->Previous &&
1091                        PreviousNotConst->Previous->is(tok::hash);
1092 
1093     if (PreviousNotConst->is(TT_TemplateCloser))
1094       return PreviousNotConst && PreviousNotConst->MatchingParen &&
1095              PreviousNotConst->MatchingParen->Previous &&
1096              PreviousNotConst->MatchingParen->Previous->isNot(tok::period) &&
1097              PreviousNotConst->MatchingParen->Previous->isNot(tok::kw_template);
1098 
1099     if (PreviousNotConst->is(tok::r_paren) && PreviousNotConst->MatchingParen &&
1100         PreviousNotConst->MatchingParen->Previous &&
1101         PreviousNotConst->MatchingParen->Previous->is(tok::kw_decltype))
1102       return true;
1103 
1104     return (!IsPPKeyword &&
1105             PreviousNotConst->isOneOf(tok::identifier, tok::kw_auto)) ||
1106            PreviousNotConst->is(TT_PointerOrReference) ||
1107            PreviousNotConst->isSimpleTypeSpecifier();
1108   }
1109 
1110   /// \brief Determine whether ')' is ending a cast.
1111   bool rParenEndsCast(const FormatToken &Tok) {
1112     // C-style casts are only used in C++ and Java.
1113     if (Style.Language != FormatStyle::LK_Cpp &&
1114         Style.Language != FormatStyle::LK_Java)
1115       return false;
1116 
1117     // Empty parens aren't casts and there are no casts at the end of the line.
1118     if (Tok.Previous == Tok.MatchingParen || !Tok.Next || !Tok.MatchingParen)
1119       return false;
1120 
1121     FormatToken *LeftOfParens = Tok.MatchingParen->getPreviousNonComment();
1122     if (LeftOfParens) {
1123       // If there is an opening parenthesis left of the current parentheses,
1124       // look past it as these might be chained casts.
1125       if (LeftOfParens->is(tok::r_paren)) {
1126         if (!LeftOfParens->MatchingParen ||
1127             !LeftOfParens->MatchingParen->Previous)
1128           return false;
1129         LeftOfParens = LeftOfParens->MatchingParen->Previous;
1130       }
1131 
1132       // If there is an identifier (or with a few exceptions a keyword) right
1133       // before the parentheses, this is unlikely to be a cast.
1134       if (LeftOfParens->Tok.getIdentifierInfo() &&
1135           !LeftOfParens->isOneOf(Keywords.kw_in, tok::kw_return, tok::kw_case,
1136                                  tok::kw_delete))
1137         return false;
1138 
1139       // Certain other tokens right before the parentheses are also signals that
1140       // this cannot be a cast.
1141       if (LeftOfParens->isOneOf(tok::at, tok::r_square, TT_OverloadedOperator,
1142                                 TT_TemplateCloser))
1143         return false;
1144     }
1145 
1146     if (Tok.Next->is(tok::question))
1147       return false;
1148 
1149     // As Java has no function types, a "(" after the ")" likely means that this
1150     // is a cast.
1151     if (Style.Language == FormatStyle::LK_Java && Tok.Next->is(tok::l_paren))
1152       return true;
1153 
1154     // If a (non-string) literal follows, this is likely a cast.
1155     if (Tok.Next->isNot(tok::string_literal) &&
1156         (Tok.Next->Tok.isLiteral() ||
1157          Tok.Next->isOneOf(tok::kw_sizeof, tok::kw_alignof)))
1158       return true;
1159 
1160     // Heuristically try to determine whether the parentheses contain a type.
1161     bool ParensAreType =
1162         !Tok.Previous ||
1163         Tok.Previous->isOneOf(TT_PointerOrReference, TT_TemplateCloser) ||
1164         Tok.Previous->isSimpleTypeSpecifier();
1165     bool ParensCouldEndDecl =
1166         Tok.Next->isOneOf(tok::equal, tok::semi, tok::l_brace, tok::greater);
1167     if (ParensAreType && !ParensCouldEndDecl)
1168       return true;
1169 
1170     // At this point, we heuristically assume that there are no casts at the
1171     // start of the line. We assume that we have found most cases where there
1172     // are by the logic above, e.g. "(void)x;".
1173     if (!LeftOfParens)
1174       return false;
1175 
1176     // If the following token is an identifier or 'this', this is a cast. All
1177     // cases where this can be something else are handled above.
1178     if (Tok.Next->isOneOf(tok::identifier, tok::kw_this))
1179       return true;
1180 
1181     if (!Tok.Next->Next)
1182       return false;
1183 
1184     // If the next token after the parenthesis is a unary operator, assume
1185     // that this is cast, unless there are unexpected tokens inside the
1186     // parenthesis.
1187     bool NextIsUnary =
1188         Tok.Next->isUnaryOperator() || Tok.Next->isOneOf(tok::amp, tok::star);
1189     if (!NextIsUnary || Tok.Next->is(tok::plus) ||
1190         !Tok.Next->Next->isOneOf(tok::identifier, tok::numeric_constant))
1191       return false;
1192     // Search for unexpected tokens.
1193     for (FormatToken *Prev = Tok.Previous; Prev != Tok.MatchingParen;
1194          Prev = Prev->Previous) {
1195       if (!Prev->isOneOf(tok::kw_const, tok::identifier, tok::coloncolon))
1196         return false;
1197     }
1198     return true;
1199   }
1200 
1201   /// \brief Return the type of the given token assuming it is * or &.
1202   TokenType determineStarAmpUsage(const FormatToken &Tok, bool IsExpression,
1203                                   bool InTemplateArgument) {
1204     if (Style.Language == FormatStyle::LK_JavaScript)
1205       return TT_BinaryOperator;
1206 
1207     const FormatToken *PrevToken = Tok.getPreviousNonComment();
1208     if (!PrevToken)
1209       return TT_UnaryOperator;
1210 
1211     const FormatToken *NextToken = Tok.getNextNonComment();
1212     if (!NextToken ||
1213         NextToken->isOneOf(tok::arrow, Keywords.kw_final,
1214                            Keywords.kw_override) ||
1215         (NextToken->is(tok::l_brace) && !NextToken->getNextNonComment()))
1216       return TT_PointerOrReference;
1217 
1218     if (PrevToken->is(tok::coloncolon))
1219       return TT_PointerOrReference;
1220 
1221     if (PrevToken->isOneOf(tok::l_paren, tok::l_square, tok::l_brace,
1222                            tok::comma, tok::semi, tok::kw_return, tok::colon,
1223                            tok::equal, tok::kw_delete, tok::kw_sizeof) ||
1224         PrevToken->isOneOf(TT_BinaryOperator, TT_ConditionalExpr,
1225                            TT_UnaryOperator, TT_CastRParen))
1226       return TT_UnaryOperator;
1227 
1228     if (NextToken->is(tok::l_square) && NextToken->isNot(TT_LambdaLSquare))
1229       return TT_PointerOrReference;
1230     if (NextToken->is(tok::kw_operator) && !IsExpression)
1231       return TT_PointerOrReference;
1232     if (NextToken->isOneOf(tok::comma, tok::semi))
1233       return TT_PointerOrReference;
1234 
1235     if (PrevToken->is(tok::r_paren) && PrevToken->MatchingParen &&
1236         PrevToken->MatchingParen->Previous &&
1237         PrevToken->MatchingParen->Previous->isOneOf(tok::kw_typeof,
1238                                                     tok::kw_decltype))
1239       return TT_PointerOrReference;
1240 
1241     if (PrevToken->Tok.isLiteral() ||
1242         PrevToken->isOneOf(tok::r_paren, tok::r_square, tok::kw_true,
1243                            tok::kw_false, tok::r_brace) ||
1244         NextToken->Tok.isLiteral() ||
1245         NextToken->isOneOf(tok::kw_true, tok::kw_false) ||
1246         NextToken->isUnaryOperator() ||
1247         // If we know we're in a template argument, there are no named
1248         // declarations. Thus, having an identifier on the right-hand side
1249         // indicates a binary operator.
1250         (InTemplateArgument && NextToken->Tok.isAnyIdentifier()))
1251       return TT_BinaryOperator;
1252 
1253     // "&&(" is quite unlikely to be two successive unary "&".
1254     if (Tok.is(tok::ampamp) && NextToken && NextToken->is(tok::l_paren))
1255       return TT_BinaryOperator;
1256 
1257     // This catches some cases where evaluation order is used as control flow:
1258     //   aaa && aaa->f();
1259     const FormatToken *NextNextToken = NextToken->getNextNonComment();
1260     if (NextNextToken && NextNextToken->is(tok::arrow))
1261       return TT_BinaryOperator;
1262 
1263     // It is very unlikely that we are going to find a pointer or reference type
1264     // definition on the RHS of an assignment.
1265     if (IsExpression && !Contexts.back().CaretFound)
1266       return TT_BinaryOperator;
1267 
1268     return TT_PointerOrReference;
1269   }
1270 
1271   TokenType determinePlusMinusCaretUsage(const FormatToken &Tok) {
1272     const FormatToken *PrevToken = Tok.getPreviousNonComment();
1273     if (!PrevToken || PrevToken->is(TT_CastRParen))
1274       return TT_UnaryOperator;
1275 
1276     // Use heuristics to recognize unary operators.
1277     if (PrevToken->isOneOf(tok::equal, tok::l_paren, tok::comma, tok::l_square,
1278                            tok::question, tok::colon, tok::kw_return,
1279                            tok::kw_case, tok::at, tok::l_brace))
1280       return TT_UnaryOperator;
1281 
1282     // There can't be two consecutive binary operators.
1283     if (PrevToken->is(TT_BinaryOperator))
1284       return TT_UnaryOperator;
1285 
1286     // Fall back to marking the token as binary operator.
1287     return TT_BinaryOperator;
1288   }
1289 
1290   /// \brief Determine whether ++/-- are pre- or post-increments/-decrements.
1291   TokenType determineIncrementUsage(const FormatToken &Tok) {
1292     const FormatToken *PrevToken = Tok.getPreviousNonComment();
1293     if (!PrevToken || PrevToken->is(TT_CastRParen))
1294       return TT_UnaryOperator;
1295     if (PrevToken->isOneOf(tok::r_paren, tok::r_square, tok::identifier))
1296       return TT_TrailingUnaryOperator;
1297 
1298     return TT_UnaryOperator;
1299   }
1300 
1301   SmallVector<Context, 8> Contexts;
1302 
1303   const FormatStyle &Style;
1304   AnnotatedLine &Line;
1305   FormatToken *CurrentToken;
1306   bool AutoFound;
1307   const AdditionalKeywords &Keywords;
1308 
1309   // Set of "<" tokens that do not open a template parameter list. If parseAngle
1310   // determines that a specific token can't be a template opener, it will make
1311   // same decision irrespective of the decisions for tokens leading up to it.
1312   // Store this information to prevent this from causing exponential runtime.
1313   llvm::SmallPtrSet<FormatToken *, 16> NonTemplateLess;
1314 };
1315 
1316 static const int PrecedenceUnaryOperator = prec::PointerToMember + 1;
1317 static const int PrecedenceArrowAndPeriod = prec::PointerToMember + 2;
1318 
1319 /// \brief Parses binary expressions by inserting fake parenthesis based on
1320 /// operator precedence.
1321 class ExpressionParser {
1322 public:
1323   ExpressionParser(const FormatStyle &Style, const AdditionalKeywords &Keywords,
1324                    AnnotatedLine &Line)
1325       : Style(Style), Keywords(Keywords), Current(Line.First) {}
1326 
1327   /// \brief Parse expressions with the given operatore precedence.
1328   void parse(int Precedence = 0) {
1329     // Skip 'return' and ObjC selector colons as they are not part of a binary
1330     // expression.
1331     while (Current && (Current->is(tok::kw_return) ||
1332                        (Current->is(tok::colon) &&
1333                         Current->isOneOf(TT_ObjCMethodExpr, TT_DictLiteral))))
1334       next();
1335 
1336     if (!Current || Precedence > PrecedenceArrowAndPeriod)
1337       return;
1338 
1339     // Conditional expressions need to be parsed separately for proper nesting.
1340     if (Precedence == prec::Conditional) {
1341       parseConditionalExpr();
1342       return;
1343     }
1344 
1345     // Parse unary operators, which all have a higher precedence than binary
1346     // operators.
1347     if (Precedence == PrecedenceUnaryOperator) {
1348       parseUnaryOperator();
1349       return;
1350     }
1351 
1352     FormatToken *Start = Current;
1353     FormatToken *LatestOperator = nullptr;
1354     unsigned OperatorIndex = 0;
1355 
1356     while (Current) {
1357       // Consume operators with higher precedence.
1358       parse(Precedence + 1);
1359 
1360       int CurrentPrecedence = getCurrentPrecedence();
1361 
1362       if (Current && Current->is(TT_SelectorName) &&
1363           Precedence == CurrentPrecedence) {
1364         if (LatestOperator)
1365           addFakeParenthesis(Start, prec::Level(Precedence));
1366         Start = Current;
1367       }
1368 
1369       // At the end of the line or when an operator with higher precedence is
1370       // found, insert fake parenthesis and return.
1371       if (!Current || (Current->closesScope() && Current->MatchingParen) ||
1372           (CurrentPrecedence != -1 && CurrentPrecedence < Precedence) ||
1373           (CurrentPrecedence == prec::Conditional &&
1374            Precedence == prec::Assignment && Current->is(tok::colon))) {
1375         break;
1376       }
1377 
1378       // Consume scopes: (), [], <> and {}
1379       if (Current->opensScope()) {
1380         while (Current && !Current->closesScope()) {
1381           next();
1382           parse();
1383         }
1384         next();
1385       } else {
1386         // Operator found.
1387         if (CurrentPrecedence == Precedence) {
1388           if (LatestOperator)
1389             LatestOperator->NextOperator = Current;
1390           LatestOperator = Current;
1391           Current->OperatorIndex = OperatorIndex;
1392           ++OperatorIndex;
1393         }
1394         next(/*SkipPastLeadingComments=*/Precedence > 0);
1395       }
1396     }
1397 
1398     if (LatestOperator && (Current || Precedence > 0)) {
1399       // LatestOperator->LastOperator = true;
1400       if (Precedence == PrecedenceArrowAndPeriod) {
1401         // Call expressions don't have a binary operator precedence.
1402         addFakeParenthesis(Start, prec::Unknown);
1403       } else {
1404         addFakeParenthesis(Start, prec::Level(Precedence));
1405       }
1406     }
1407   }
1408 
1409 private:
1410   /// \brief Gets the precedence (+1) of the given token for binary operators
1411   /// and other tokens that we treat like binary operators.
1412   int getCurrentPrecedence() {
1413     if (Current) {
1414       const FormatToken *NextNonComment = Current->getNextNonComment();
1415       if (Current->is(TT_ConditionalExpr))
1416         return prec::Conditional;
1417       if (NextNonComment && NextNonComment->is(tok::colon) &&
1418           NextNonComment->is(TT_DictLiteral))
1419         return prec::Comma;
1420       if (Current->is(TT_LambdaArrow))
1421         return prec::Comma;
1422       if (Current->is(TT_JsFatArrow))
1423         return prec::Assignment;
1424       if (Current->isOneOf(tok::semi, TT_InlineASMColon, TT_SelectorName,
1425                            TT_JsComputedPropertyName) ||
1426           (Current->is(tok::comment) && NextNonComment &&
1427            NextNonComment->is(TT_SelectorName)))
1428         return 0;
1429       if (Current->is(TT_RangeBasedForLoopColon))
1430         return prec::Comma;
1431       if ((Style.Language == FormatStyle::LK_Java ||
1432            Style.Language == FormatStyle::LK_JavaScript) &&
1433           Current->is(Keywords.kw_instanceof))
1434         return prec::Relational;
1435       if (Style.Language == FormatStyle::LK_JavaScript &&
1436           Current->is(Keywords.kw_in))
1437         return prec::Relational;
1438       if (Current->is(TT_BinaryOperator) || Current->is(tok::comma))
1439         return Current->getPrecedence();
1440       if (Current->isOneOf(tok::period, tok::arrow))
1441         return PrecedenceArrowAndPeriod;
1442       if (Style.Language == FormatStyle::LK_Java &&
1443           Current->isOneOf(Keywords.kw_extends, Keywords.kw_implements,
1444                            Keywords.kw_throws))
1445         return 0;
1446     }
1447     return -1;
1448   }
1449 
1450   void addFakeParenthesis(FormatToken *Start, prec::Level Precedence) {
1451     Start->FakeLParens.push_back(Precedence);
1452     if (Precedence > prec::Unknown)
1453       Start->StartsBinaryExpression = true;
1454     if (Current) {
1455       FormatToken *Previous = Current->Previous;
1456       while (Previous->is(tok::comment) && Previous->Previous)
1457         Previous = Previous->Previous;
1458       ++Previous->FakeRParens;
1459       if (Precedence > prec::Unknown)
1460         Previous->EndsBinaryExpression = true;
1461     }
1462   }
1463 
1464   /// \brief Parse unary operator expressions and surround them with fake
1465   /// parentheses if appropriate.
1466   void parseUnaryOperator() {
1467     if (!Current || Current->isNot(TT_UnaryOperator)) {
1468       parse(PrecedenceArrowAndPeriod);
1469       return;
1470     }
1471 
1472     FormatToken *Start = Current;
1473     next();
1474     parseUnaryOperator();
1475 
1476     // The actual precedence doesn't matter.
1477     addFakeParenthesis(Start, prec::Unknown);
1478   }
1479 
1480   void parseConditionalExpr() {
1481     while (Current && Current->isTrailingComment()) {
1482       next();
1483     }
1484     FormatToken *Start = Current;
1485     parse(prec::LogicalOr);
1486     if (!Current || !Current->is(tok::question))
1487       return;
1488     next();
1489     parse(prec::Assignment);
1490     if (!Current || Current->isNot(TT_ConditionalExpr))
1491       return;
1492     next();
1493     parse(prec::Assignment);
1494     addFakeParenthesis(Start, prec::Conditional);
1495   }
1496 
1497   void next(bool SkipPastLeadingComments = true) {
1498     if (Current)
1499       Current = Current->Next;
1500     while (Current &&
1501            (Current->NewlinesBefore == 0 || SkipPastLeadingComments) &&
1502            Current->isTrailingComment())
1503       Current = Current->Next;
1504   }
1505 
1506   const FormatStyle &Style;
1507   const AdditionalKeywords &Keywords;
1508   FormatToken *Current;
1509 };
1510 
1511 } // end anonymous namespace
1512 
1513 void TokenAnnotator::setCommentLineLevels(
1514     SmallVectorImpl<AnnotatedLine *> &Lines) {
1515   const AnnotatedLine *NextNonCommentLine = nullptr;
1516   for (SmallVectorImpl<AnnotatedLine *>::reverse_iterator I = Lines.rbegin(),
1517                                                           E = Lines.rend();
1518        I != E; ++I) {
1519     if (NextNonCommentLine && (*I)->First->is(tok::comment) &&
1520         (*I)->First->Next == nullptr)
1521       (*I)->Level = NextNonCommentLine->Level;
1522     else
1523       NextNonCommentLine = (*I)->First->isNot(tok::r_brace) ? (*I) : nullptr;
1524 
1525     setCommentLineLevels((*I)->Children);
1526   }
1527 }
1528 
1529 void TokenAnnotator::annotate(AnnotatedLine &Line) {
1530   for (SmallVectorImpl<AnnotatedLine *>::iterator I = Line.Children.begin(),
1531                                                   E = Line.Children.end();
1532        I != E; ++I) {
1533     annotate(**I);
1534   }
1535   AnnotatingParser Parser(Style, Line, Keywords);
1536   Line.Type = Parser.parseLine();
1537   if (Line.Type == LT_Invalid)
1538     return;
1539 
1540   ExpressionParser ExprParser(Style, Keywords, Line);
1541   ExprParser.parse();
1542 
1543   if (Line.startsWith(TT_ObjCMethodSpecifier))
1544     Line.Type = LT_ObjCMethodDecl;
1545   else if (Line.startsWith(TT_ObjCDecl))
1546     Line.Type = LT_ObjCDecl;
1547   else if (Line.startsWith(TT_ObjCProperty))
1548     Line.Type = LT_ObjCProperty;
1549 
1550   Line.First->SpacesRequiredBefore = 1;
1551   Line.First->CanBreakBefore = Line.First->MustBreakBefore;
1552 }
1553 
1554 // This function heuristically determines whether 'Current' starts the name of a
1555 // function declaration.
1556 static bool isFunctionDeclarationName(const FormatToken &Current) {
1557   auto skipOperatorName = [](const FormatToken* Next) -> const FormatToken* {
1558     for (; Next; Next = Next->Next) {
1559       if (Next->is(TT_OverloadedOperatorLParen))
1560         return Next;
1561       if (Next->is(TT_OverloadedOperator))
1562         continue;
1563       if (Next->isOneOf(tok::kw_new, tok::kw_delete)) {
1564         // For 'new[]' and 'delete[]'.
1565         if (Next->Next && Next->Next->is(tok::l_square) &&
1566             Next->Next->Next && Next->Next->Next->is(tok::r_square))
1567           Next = Next->Next->Next;
1568         continue;
1569       }
1570 
1571       break;
1572     }
1573     return nullptr;
1574   };
1575 
1576   const FormatToken *Next = Current.Next;
1577   if (Current.is(tok::kw_operator)) {
1578     if (Current.Previous && Current.Previous->is(tok::coloncolon))
1579       return false;
1580     Next = skipOperatorName(Next);
1581   } else {
1582     if (!Current.is(TT_StartOfName) || Current.NestingLevel != 0)
1583       return false;
1584     for (; Next; Next = Next->Next) {
1585       if (Next->is(TT_TemplateOpener)) {
1586         Next = Next->MatchingParen;
1587       } else if (Next->is(tok::coloncolon)) {
1588         Next = Next->Next;
1589         if (!Next)
1590           return false;
1591         if (Next->is(tok::kw_operator)) {
1592           Next = skipOperatorName(Next->Next);
1593           break;
1594         }
1595         if (!Next->is(tok::identifier))
1596           return false;
1597       } else if (Next->is(tok::l_paren)) {
1598         break;
1599       } else {
1600         return false;
1601       }
1602     }
1603   }
1604 
1605   if (!Next || !Next->is(tok::l_paren))
1606     return false;
1607   if (Next->Next == Next->MatchingParen)
1608     return true;
1609   for (const FormatToken *Tok = Next->Next; Tok && Tok != Next->MatchingParen;
1610        Tok = Tok->Next) {
1611     if (Tok->is(tok::kw_const) || Tok->isSimpleTypeSpecifier() ||
1612         Tok->isOneOf(TT_PointerOrReference, TT_StartOfName))
1613       return true;
1614     if (Tok->isOneOf(tok::l_brace, tok::string_literal, TT_ObjCMethodExpr) ||
1615         Tok->Tok.isLiteral())
1616       return false;
1617   }
1618   return false;
1619 }
1620 
1621 bool TokenAnnotator::mustBreakForReturnType(const AnnotatedLine &Line) const {
1622   assert(Line.MightBeFunctionDecl);
1623 
1624   if ((Style.AlwaysBreakAfterReturnType == FormatStyle::RTBS_TopLevel ||
1625        Style.AlwaysBreakAfterReturnType ==
1626            FormatStyle::RTBS_TopLevelDefinitions) &&
1627       Line.Level > 0)
1628     return false;
1629 
1630   switch (Style.AlwaysBreakAfterReturnType) {
1631   case FormatStyle::RTBS_None:
1632     return false;
1633   case FormatStyle::RTBS_All:
1634   case FormatStyle::RTBS_TopLevel:
1635     return true;
1636   case FormatStyle::RTBS_AllDefinitions:
1637   case FormatStyle::RTBS_TopLevelDefinitions:
1638     return Line.mightBeFunctionDefinition();
1639   }
1640 
1641   return false;
1642 }
1643 
1644 void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) {
1645   for (SmallVectorImpl<AnnotatedLine *>::iterator I = Line.Children.begin(),
1646                                                   E = Line.Children.end();
1647        I != E; ++I) {
1648     calculateFormattingInformation(**I);
1649   }
1650 
1651   Line.First->TotalLength =
1652       Line.First->IsMultiline ? Style.ColumnLimit : Line.First->ColumnWidth;
1653   if (!Line.First->Next)
1654     return;
1655   FormatToken *Current = Line.First->Next;
1656   bool InFunctionDecl = Line.MightBeFunctionDecl;
1657   while (Current) {
1658     if (isFunctionDeclarationName(*Current))
1659       Current->Type = TT_FunctionDeclarationName;
1660     if (Current->is(TT_LineComment)) {
1661       if (Current->Previous->BlockKind == BK_BracedInit &&
1662           Current->Previous->opensScope())
1663         Current->SpacesRequiredBefore = Style.Cpp11BracedListStyle ? 0 : 1;
1664       else
1665         Current->SpacesRequiredBefore = Style.SpacesBeforeTrailingComments;
1666 
1667       // If we find a trailing comment, iterate backwards to determine whether
1668       // it seems to relate to a specific parameter. If so, break before that
1669       // parameter to avoid changing the comment's meaning. E.g. don't move 'b'
1670       // to the previous line in:
1671       //   SomeFunction(a,
1672       //                b, // comment
1673       //                c);
1674       if (!Current->HasUnescapedNewline) {
1675         for (FormatToken *Parameter = Current->Previous; Parameter;
1676              Parameter = Parameter->Previous) {
1677           if (Parameter->isOneOf(tok::comment, tok::r_brace))
1678             break;
1679           if (Parameter->Previous && Parameter->Previous->is(tok::comma)) {
1680             if (!Parameter->Previous->is(TT_CtorInitializerComma) &&
1681                 Parameter->HasUnescapedNewline)
1682               Parameter->MustBreakBefore = true;
1683             break;
1684           }
1685         }
1686       }
1687     } else if (Current->SpacesRequiredBefore == 0 &&
1688                spaceRequiredBefore(Line, *Current)) {
1689       Current->SpacesRequiredBefore = 1;
1690     }
1691 
1692     Current->MustBreakBefore =
1693         Current->MustBreakBefore || mustBreakBefore(Line, *Current);
1694 
1695     if (!Current->MustBreakBefore && InFunctionDecl &&
1696         Current->is(TT_FunctionDeclarationName))
1697       Current->MustBreakBefore = mustBreakForReturnType(Line);
1698 
1699     Current->CanBreakBefore =
1700         Current->MustBreakBefore || canBreakBefore(Line, *Current);
1701     unsigned ChildSize = 0;
1702     if (Current->Previous->Children.size() == 1) {
1703       FormatToken &LastOfChild = *Current->Previous->Children[0]->Last;
1704       ChildSize = LastOfChild.isTrailingComment() ? Style.ColumnLimit
1705                                                   : LastOfChild.TotalLength + 1;
1706     }
1707     const FormatToken *Prev = Current->Previous;
1708     if (Current->MustBreakBefore || Prev->Children.size() > 1 ||
1709         (Prev->Children.size() == 1 &&
1710          Prev->Children[0]->First->MustBreakBefore) ||
1711         Current->IsMultiline)
1712       Current->TotalLength = Prev->TotalLength + Style.ColumnLimit;
1713     else
1714       Current->TotalLength = Prev->TotalLength + Current->ColumnWidth +
1715                              ChildSize + Current->SpacesRequiredBefore;
1716 
1717     if (Current->is(TT_CtorInitializerColon))
1718       InFunctionDecl = false;
1719 
1720     // FIXME: Only calculate this if CanBreakBefore is true once static
1721     // initializers etc. are sorted out.
1722     // FIXME: Move magic numbers to a better place.
1723     Current->SplitPenalty = 20 * Current->BindingStrength +
1724                             splitPenalty(Line, *Current, InFunctionDecl);
1725 
1726     Current = Current->Next;
1727   }
1728 
1729   calculateUnbreakableTailLengths(Line);
1730   for (Current = Line.First; Current != nullptr; Current = Current->Next) {
1731     if (Current->Role)
1732       Current->Role->precomputeFormattingInfos(Current);
1733   }
1734 
1735   DEBUG({ printDebugInfo(Line); });
1736 }
1737 
1738 void TokenAnnotator::calculateUnbreakableTailLengths(AnnotatedLine &Line) {
1739   unsigned UnbreakableTailLength = 0;
1740   FormatToken *Current = Line.Last;
1741   while (Current) {
1742     Current->UnbreakableTailLength = UnbreakableTailLength;
1743     if (Current->CanBreakBefore ||
1744         Current->isOneOf(tok::comment, tok::string_literal)) {
1745       UnbreakableTailLength = 0;
1746     } else {
1747       UnbreakableTailLength +=
1748           Current->ColumnWidth + Current->SpacesRequiredBefore;
1749     }
1750     Current = Current->Previous;
1751   }
1752 }
1753 
1754 unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
1755                                       const FormatToken &Tok,
1756                                       bool InFunctionDecl) {
1757   const FormatToken &Left = *Tok.Previous;
1758   const FormatToken &Right = Tok;
1759 
1760   if (Left.is(tok::semi))
1761     return 0;
1762 
1763   if (Style.Language == FormatStyle::LK_Java) {
1764     if (Right.isOneOf(Keywords.kw_extends, Keywords.kw_throws))
1765       return 1;
1766     if (Right.is(Keywords.kw_implements))
1767       return 2;
1768     if (Left.is(tok::comma) && Left.NestingLevel == 0)
1769       return 3;
1770   } else if (Style.Language == FormatStyle::LK_JavaScript) {
1771     if (Right.is(Keywords.kw_function) && Left.isNot(tok::comma))
1772       return 100;
1773     if (Left.is(TT_JsTypeColon))
1774       return 35;
1775   }
1776 
1777   if (Left.is(tok::comma) || (Right.is(tok::identifier) && Right.Next &&
1778                               Right.Next->is(TT_DictLiteral)))
1779     return 1;
1780   if (Right.is(tok::l_square)) {
1781     if (Style.Language == FormatStyle::LK_Proto)
1782       return 1;
1783     if (Left.is(tok::r_square))
1784       return 200;
1785     // Slightly prefer formatting local lambda definitions like functions.
1786     if (Right.is(TT_LambdaLSquare) && Left.is(tok::equal))
1787       return 35;
1788     if (!Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
1789                        TT_ArrayInitializerLSquare))
1790       return 500;
1791   }
1792 
1793   if (Right.isOneOf(TT_StartOfName, TT_FunctionDeclarationName) ||
1794       Right.is(tok::kw_operator)) {
1795     if (Line.startsWith(tok::kw_for) && Right.PartOfMultiVariableDeclStmt)
1796       return 3;
1797     if (Left.is(TT_StartOfName))
1798       return 110;
1799     if (InFunctionDecl && Right.NestingLevel == 0)
1800       return Style.PenaltyReturnTypeOnItsOwnLine;
1801     return 200;
1802   }
1803   if (Right.is(TT_PointerOrReference))
1804     return 190;
1805   if (Right.is(TT_LambdaArrow))
1806     return 110;
1807   if (Left.is(tok::equal) && Right.is(tok::l_brace))
1808     return 150;
1809   if (Left.is(TT_CastRParen))
1810     return 100;
1811   if (Left.is(tok::coloncolon) ||
1812       (Right.is(tok::period) && Style.Language == FormatStyle::LK_Proto))
1813     return 500;
1814   if (Left.isOneOf(tok::kw_class, tok::kw_struct))
1815     return 5000;
1816 
1817   if (Left.isOneOf(TT_RangeBasedForLoopColon, TT_InheritanceColon))
1818     return 2;
1819 
1820   if (Right.isMemberAccess()) {
1821     // Breaking before the "./->" of a chained call/member access is reasonably
1822     // cheap, as formatting those with one call per line is generally
1823     // desirable. In particular, it should be cheaper to break before the call
1824     // than it is to break inside a call's parameters, which could lead to weird
1825     // "hanging" indents. The exception is the very last "./->" to support this
1826     // frequent pattern:
1827     //
1828     //   aaaaaaaa.aaaaaaaa.bbbbbbb().ccccccccccccccccccccc(
1829     //       dddddddd);
1830     //
1831     // which might otherwise be blown up onto many lines. Here, clang-format
1832     // won't produce "hanging" indents anyway as there is no other trailing
1833     // call.
1834     //
1835     // Also apply higher penalty is not a call as that might lead to a wrapping
1836     // like:
1837     //
1838     //   aaaaaaa
1839     //       .aaaaaaaaa.bbbbbbbb(cccccccc);
1840     return !Right.NextOperator || !Right.NextOperator->Previous->closesScope()
1841                ? 150
1842                : 35;
1843   }
1844 
1845   if (Right.is(TT_TrailingAnnotation) &&
1846       (!Right.Next || Right.Next->isNot(tok::l_paren))) {
1847     // Moving trailing annotations to the next line is fine for ObjC method
1848     // declarations.
1849     if (Line.startsWith(TT_ObjCMethodSpecifier))
1850       return 10;
1851     // Generally, breaking before a trailing annotation is bad unless it is
1852     // function-like. It seems to be especially preferable to keep standard
1853     // annotations (i.e. "const", "final" and "override") on the same line.
1854     // Use a slightly higher penalty after ")" so that annotations like
1855     // "const override" are kept together.
1856     bool is_short_annotation = Right.TokenText.size() < 10;
1857     return (Left.is(tok::r_paren) ? 100 : 120) + (is_short_annotation ? 50 : 0);
1858   }
1859 
1860   // In for-loops, prefer breaking at ',' and ';'.
1861   if (Line.startsWith(tok::kw_for) && Left.is(tok::equal))
1862     return 4;
1863 
1864   // In Objective-C method expressions, prefer breaking before "param:" over
1865   // breaking after it.
1866   if (Right.is(TT_SelectorName))
1867     return 0;
1868   if (Left.is(tok::colon) && Left.is(TT_ObjCMethodExpr))
1869     return Line.MightBeFunctionDecl ? 50 : 500;
1870 
1871   if (Left.is(tok::l_paren) && InFunctionDecl &&
1872       Style.AlignAfterOpenBracket != FormatStyle::BAS_DontAlign)
1873     return 100;
1874   if (Left.is(tok::l_paren) && Left.Previous &&
1875       Left.Previous->isOneOf(tok::kw_if, tok::kw_for))
1876     return 1000;
1877   if (Left.is(tok::equal) && InFunctionDecl)
1878     return 110;
1879   if (Right.is(tok::r_brace))
1880     return 1;
1881   if (Left.is(TT_TemplateOpener))
1882     return 100;
1883   if (Left.opensScope()) {
1884     if (Style.AlignAfterOpenBracket == FormatStyle::BAS_DontAlign)
1885       return 0;
1886     return Left.ParameterCount > 1 ? Style.PenaltyBreakBeforeFirstCallParameter
1887                                    : 19;
1888   }
1889   if (Left.is(TT_JavaAnnotation))
1890     return 50;
1891 
1892   if (Right.is(tok::lessless)) {
1893     if (Left.is(tok::string_literal) &&
1894         (Right.NextOperator || Right.OperatorIndex != 1)) {
1895       StringRef Content = Left.TokenText;
1896       if (Content.startswith("\""))
1897         Content = Content.drop_front(1);
1898       if (Content.endswith("\""))
1899         Content = Content.drop_back(1);
1900       Content = Content.trim();
1901       if (Content.size() > 1 &&
1902           (Content.back() == ':' || Content.back() == '='))
1903         return 25;
1904     }
1905     return 1; // Breaking at a << is really cheap.
1906   }
1907   if (Left.is(TT_ConditionalExpr))
1908     return prec::Conditional;
1909   prec::Level Level = Left.getPrecedence();
1910   if (Level != prec::Unknown)
1911     return Level;
1912   Level = Right.getPrecedence();
1913   if (Level != prec::Unknown)
1914     return Level;
1915 
1916   return 3;
1917 }
1918 
1919 bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
1920                                           const FormatToken &Left,
1921                                           const FormatToken &Right) {
1922   if (Left.is(tok::kw_return) && Right.isNot(tok::semi))
1923     return true;
1924   if (Style.ObjCSpaceAfterProperty && Line.Type == LT_ObjCProperty &&
1925       Left.Tok.getObjCKeywordID() == tok::objc_property)
1926     return true;
1927   if (Right.is(tok::hashhash))
1928     return Left.is(tok::hash);
1929   if (Left.isOneOf(tok::hashhash, tok::hash))
1930     return Right.is(tok::hash);
1931   if (Left.is(tok::l_paren) && Right.is(tok::r_paren))
1932     return Style.SpaceInEmptyParentheses;
1933   if (Left.is(tok::l_paren) || Right.is(tok::r_paren))
1934     return (Right.is(TT_CastRParen) ||
1935             (Left.MatchingParen && Left.MatchingParen->is(TT_CastRParen)))
1936                ? Style.SpacesInCStyleCastParentheses
1937                : Style.SpacesInParentheses;
1938   if (Right.isOneOf(tok::semi, tok::comma))
1939     return false;
1940   if (Right.is(tok::less) &&
1941       (Left.is(tok::kw_template) ||
1942        (Line.Type == LT_ObjCDecl && Style.ObjCSpaceBeforeProtocolList)))
1943     return true;
1944   if (Left.isOneOf(tok::exclaim, tok::tilde))
1945     return false;
1946   if (Left.is(tok::at) &&
1947       Right.isOneOf(tok::identifier, tok::string_literal, tok::char_constant,
1948                     tok::numeric_constant, tok::l_paren, tok::l_brace,
1949                     tok::kw_true, tok::kw_false))
1950     return false;
1951   if (Left.is(tok::colon))
1952     return !Left.is(TT_ObjCMethodExpr);
1953   if (Left.is(tok::coloncolon))
1954     return false;
1955   if (Left.is(tok::less) || Right.isOneOf(tok::greater, tok::less))
1956     return false;
1957   if (Right.is(tok::ellipsis))
1958     return Left.Tok.isLiteral();
1959   if (Left.is(tok::l_square) && Right.is(tok::amp))
1960     return false;
1961   if (Right.is(TT_PointerOrReference))
1962     return (Left.is(tok::r_paren) && Left.MatchingParen &&
1963             (Left.MatchingParen->is(TT_OverloadedOperatorLParen) ||
1964              (Left.MatchingParen->Previous &&
1965               Left.MatchingParen->Previous->is(TT_FunctionDeclarationName)))) ||
1966            (Left.Tok.isLiteral() ||
1967             (!Left.isOneOf(TT_PointerOrReference, tok::l_paren) &&
1968              (Style.PointerAlignment != FormatStyle::PAS_Left ||
1969               Line.IsMultiVariableDeclStmt)));
1970   if (Right.is(TT_FunctionTypeLParen) && Left.isNot(tok::l_paren) &&
1971       (!Left.is(TT_PointerOrReference) ||
1972        (Style.PointerAlignment != FormatStyle::PAS_Right &&
1973         !Line.IsMultiVariableDeclStmt)))
1974     return true;
1975   if (Left.is(TT_PointerOrReference))
1976     return Right.Tok.isLiteral() ||
1977            Right.isOneOf(TT_BlockComment, Keywords.kw_final,
1978                          Keywords.kw_override) ||
1979            (Right.is(tok::l_brace) && Right.BlockKind == BK_Block) ||
1980            (!Right.isOneOf(TT_PointerOrReference, TT_ArraySubscriptLSquare,
1981                            tok::l_paren) &&
1982             (Style.PointerAlignment != FormatStyle::PAS_Right &&
1983              !Line.IsMultiVariableDeclStmt) &&
1984             Left.Previous &&
1985             !Left.Previous->isOneOf(tok::l_paren, tok::coloncolon));
1986   if (Right.is(tok::star) && Left.is(tok::l_paren))
1987     return false;
1988   if (Left.is(tok::l_square))
1989     return (Left.is(TT_ArrayInitializerLSquare) &&
1990             Style.SpacesInContainerLiterals && Right.isNot(tok::r_square)) ||
1991            (Left.is(TT_ArraySubscriptLSquare) && Style.SpacesInSquareBrackets &&
1992             Right.isNot(tok::r_square));
1993   if (Right.is(tok::r_square))
1994     return Right.MatchingParen &&
1995            ((Style.SpacesInContainerLiterals &&
1996              Right.MatchingParen->is(TT_ArrayInitializerLSquare)) ||
1997             (Style.SpacesInSquareBrackets &&
1998              Right.MatchingParen->is(TT_ArraySubscriptLSquare)));
1999   if (Right.is(tok::l_square) &&
2000       !Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare) &&
2001       !Left.isOneOf(tok::numeric_constant, TT_DictLiteral))
2002     return false;
2003   if (Left.is(tok::l_brace) && Right.is(tok::r_brace))
2004     return !Left.Children.empty(); // No spaces in "{}".
2005   if ((Left.is(tok::l_brace) && Left.BlockKind != BK_Block) ||
2006       (Right.is(tok::r_brace) && Right.MatchingParen &&
2007        Right.MatchingParen->BlockKind != BK_Block))
2008     return !Style.Cpp11BracedListStyle;
2009   if (Left.is(TT_BlockComment))
2010     return !Left.TokenText.endswith("=*/");
2011   if (Right.is(tok::l_paren)) {
2012     if (Left.is(tok::r_paren) && Left.is(TT_AttributeParen))
2013       return true;
2014     return Line.Type == LT_ObjCDecl || Left.is(tok::semi) ||
2015            (Style.SpaceBeforeParens != FormatStyle::SBPO_Never &&
2016             (Left.isOneOf(tok::kw_if, tok::pp_elif, tok::kw_for, tok::kw_while,
2017                           tok::kw_switch, tok::kw_case, TT_ForEachMacro,
2018                           TT_ObjCForIn) ||
2019              (Left.isOneOf(tok::kw_try, Keywords.kw___except, tok::kw_catch,
2020                            tok::kw_new, tok::kw_delete) &&
2021               (!Left.Previous || Left.Previous->isNot(tok::period))))) ||
2022            (Style.SpaceBeforeParens == FormatStyle::SBPO_Always &&
2023             (Left.is(tok::identifier) || Left.isFunctionLikeKeyword() ||
2024              Left.is(tok::r_paren)) &&
2025             Line.Type != LT_PreprocessorDirective);
2026   }
2027   if (Left.is(tok::at) && Right.Tok.getObjCKeywordID() != tok::objc_not_keyword)
2028     return false;
2029   if (Right.is(TT_UnaryOperator))
2030     return !Left.isOneOf(tok::l_paren, tok::l_square, tok::at) &&
2031            (Left.isNot(tok::colon) || Left.isNot(TT_ObjCMethodExpr));
2032   if ((Left.isOneOf(tok::identifier, tok::greater, tok::r_square,
2033                     tok::r_paren) ||
2034        Left.isSimpleTypeSpecifier()) &&
2035       Right.is(tok::l_brace) && Right.getNextNonComment() &&
2036       Right.BlockKind != BK_Block)
2037     return false;
2038   if (Left.is(tok::period) || Right.is(tok::period))
2039     return false;
2040   if (Right.is(tok::hash) && Left.is(tok::identifier) && Left.TokenText == "L")
2041     return false;
2042   if (Left.is(TT_TemplateCloser) && Left.MatchingParen &&
2043       Left.MatchingParen->Previous &&
2044       Left.MatchingParen->Previous->is(tok::period))
2045     // A.<B>DoSomething();
2046     return false;
2047   if (Left.is(TT_TemplateCloser) && Right.is(tok::l_square))
2048     return false;
2049   return true;
2050 }
2051 
2052 bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
2053                                          const FormatToken &Right) {
2054   const FormatToken &Left = *Right.Previous;
2055   if (Right.Tok.getIdentifierInfo() && Left.Tok.getIdentifierInfo())
2056     return true; // Never ever merge two identifiers.
2057   if (Style.Language == FormatStyle::LK_Cpp) {
2058     if (Left.is(tok::kw_operator))
2059       return Right.is(tok::coloncolon);
2060   } else if (Style.Language == FormatStyle::LK_Proto) {
2061     if (Right.is(tok::period) &&
2062         Left.isOneOf(Keywords.kw_optional, Keywords.kw_required,
2063                      Keywords.kw_repeated, Keywords.kw_extend))
2064       return true;
2065     if (Right.is(tok::l_paren) &&
2066         Left.isOneOf(Keywords.kw_returns, Keywords.kw_option))
2067       return true;
2068   } else if (Style.Language == FormatStyle::LK_JavaScript) {
2069     if (Left.is(TT_JsFatArrow))
2070       return true;
2071     if (Left.isOneOf(Keywords.kw_let, Keywords.kw_var, Keywords.kw_in,
2072                      Keywords.kw_of) &&
2073         (!Left.Previous || !Left.Previous->is(tok::period)))
2074       return true;
2075     if (Left.is(tok::kw_default) && Left.Previous &&
2076         Left.Previous->is(tok::kw_export))
2077       return true;
2078     if (Left.is(Keywords.kw_is) && Right.is(tok::l_brace))
2079       return true;
2080     if (Right.isOneOf(TT_JsTypeColon, TT_JsTypeOptionalQuestion))
2081       return false;
2082     if (Left.is(TT_JsTypeOperator) || Right.is(TT_JsTypeOperator))
2083       return false;
2084     if ((Left.is(tok::l_brace) || Right.is(tok::r_brace)) &&
2085         Line.First->isOneOf(Keywords.kw_import, tok::kw_export))
2086       return false;
2087     if (Left.is(tok::ellipsis))
2088       return false;
2089     if (Left.is(TT_TemplateCloser) &&
2090         !Right.isOneOf(tok::equal, tok::l_brace, tok::comma, tok::l_square,
2091                        Keywords.kw_implements, Keywords.kw_extends))
2092       // Type assertions ('<type>expr') are not followed by whitespace. Other
2093       // locations that should have whitespace following are identified by the
2094       // above set of follower tokens.
2095       return false;
2096   } else if (Style.Language == FormatStyle::LK_Java) {
2097     if (Left.is(tok::r_square) && Right.is(tok::l_brace))
2098       return true;
2099     if (Left.is(Keywords.kw_synchronized) && Right.is(tok::l_paren))
2100       return Style.SpaceBeforeParens != FormatStyle::SBPO_Never;
2101     if ((Left.isOneOf(tok::kw_static, tok::kw_public, tok::kw_private,
2102                       tok::kw_protected) ||
2103          Left.isOneOf(Keywords.kw_final, Keywords.kw_abstract,
2104                       Keywords.kw_native)) &&
2105         Right.is(TT_TemplateOpener))
2106       return true;
2107   }
2108   if (Left.is(TT_ImplicitStringLiteral))
2109     return Right.WhitespaceRange.getBegin() != Right.WhitespaceRange.getEnd();
2110   if (Line.Type == LT_ObjCMethodDecl) {
2111     if (Left.is(TT_ObjCMethodSpecifier))
2112       return true;
2113     if (Left.is(tok::r_paren) && Right.is(tok::identifier))
2114       // Don't space between ')' and <id>
2115       return false;
2116   }
2117   if (Line.Type == LT_ObjCProperty &&
2118       (Right.is(tok::equal) || Left.is(tok::equal)))
2119     return false;
2120 
2121   if (Right.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow) ||
2122       Left.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow))
2123     return true;
2124   if (Right.is(TT_OverloadedOperatorLParen))
2125     return Style.SpaceBeforeParens == FormatStyle::SBPO_Always;
2126   if (Left.is(tok::comma))
2127     return true;
2128   if (Right.is(tok::comma))
2129     return false;
2130   if (Right.isOneOf(TT_CtorInitializerColon, TT_ObjCBlockLParen))
2131     return true;
2132   if (Right.is(tok::colon)) {
2133     if (Line.First->isOneOf(tok::kw_case, tok::kw_default) ||
2134         !Right.getNextNonComment() || Right.getNextNonComment()->is(tok::semi))
2135       return false;
2136     if (Right.is(TT_ObjCMethodExpr))
2137       return false;
2138     if (Left.is(tok::question))
2139       return false;
2140     if (Right.is(TT_InlineASMColon) && Left.is(tok::coloncolon))
2141       return false;
2142     if (Right.is(TT_DictLiteral))
2143       return Style.SpacesInContainerLiterals;
2144     return true;
2145   }
2146   if (Left.is(TT_UnaryOperator))
2147     return Right.is(TT_BinaryOperator);
2148 
2149   // If the next token is a binary operator or a selector name, we have
2150   // incorrectly classified the parenthesis as a cast. FIXME: Detect correctly.
2151   if (Left.is(TT_CastRParen))
2152     return Style.SpaceAfterCStyleCast ||
2153            Right.isOneOf(TT_BinaryOperator, TT_SelectorName);
2154 
2155   if (Left.is(tok::greater) && Right.is(tok::greater))
2156     return Right.is(TT_TemplateCloser) && Left.is(TT_TemplateCloser) &&
2157            (Style.Standard != FormatStyle::LS_Cpp11 || Style.SpacesInAngles);
2158   if (Right.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar) ||
2159       Left.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar))
2160     return false;
2161   if (!Style.SpaceBeforeAssignmentOperators &&
2162       Right.getPrecedence() == prec::Assignment)
2163     return false;
2164   if (Right.is(tok::coloncolon) && Left.isNot(tok::l_brace))
2165     return (Left.is(TT_TemplateOpener) &&
2166             Style.Standard == FormatStyle::LS_Cpp03) ||
2167            !(Left.isOneOf(tok::identifier, tok::l_paren, tok::r_paren,
2168                           tok::l_square) ||
2169              Left.isOneOf(TT_TemplateCloser, TT_TemplateOpener));
2170   if ((Left.is(TT_TemplateOpener)) != (Right.is(TT_TemplateCloser)))
2171     return Style.SpacesInAngles;
2172   if ((Right.is(TT_BinaryOperator) && !Left.is(tok::l_paren)) ||
2173       (Left.isOneOf(TT_BinaryOperator, TT_ConditionalExpr) &&
2174        !Right.is(tok::r_paren)))
2175     return true;
2176   if (Left.is(TT_TemplateCloser) && Right.is(tok::l_paren) &&
2177       Right.isNot(TT_FunctionTypeLParen))
2178     return Style.SpaceBeforeParens == FormatStyle::SBPO_Always;
2179   if (Right.is(TT_TemplateOpener) && Left.is(tok::r_paren) &&
2180       Left.MatchingParen && Left.MatchingParen->is(TT_OverloadedOperatorLParen))
2181     return false;
2182   if (Right.is(tok::less) && Left.isNot(tok::l_paren) &&
2183       Line.startsWith(tok::hash))
2184     return true;
2185   if (Right.is(TT_TrailingUnaryOperator))
2186     return false;
2187   if (Left.is(TT_RegexLiteral))
2188     return false;
2189   return spaceRequiredBetween(Line, Left, Right);
2190 }
2191 
2192 // Returns 'true' if 'Tok' is a brace we'd want to break before in Allman style.
2193 static bool isAllmanBrace(const FormatToken &Tok) {
2194   return Tok.is(tok::l_brace) && Tok.BlockKind == BK_Block &&
2195          !Tok.isOneOf(TT_ObjCBlockLBrace, TT_DictLiteral);
2196 }
2197 
2198 bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
2199                                      const FormatToken &Right) {
2200   const FormatToken &Left = *Right.Previous;
2201   if (Right.NewlinesBefore > 1 && Style.MaxEmptyLinesToKeep > 0)
2202     return true;
2203 
2204   if (Style.Language == FormatStyle::LK_JavaScript) {
2205     // FIXME: This might apply to other languages and token kinds.
2206     if (Right.is(tok::string_literal) && Left.is(tok::plus) && Left.Previous &&
2207         Left.Previous->is(tok::string_literal))
2208       return true;
2209     if (Left.is(TT_DictLiteral) && Left.is(tok::l_brace) && Line.Level == 0 &&
2210         Left.Previous && Left.Previous->is(tok::equal) &&
2211         Line.First->isOneOf(tok::identifier, Keywords.kw_import, tok::kw_export,
2212                             tok::kw_const) &&
2213         // kw_var/kw_let are pseudo-tokens that are tok::identifier, so match
2214         // above.
2215         !Line.First->isOneOf(Keywords.kw_var, Keywords.kw_let))
2216       // Object literals on the top level of a file are treated as "enum-style".
2217       // Each key/value pair is put on a separate line, instead of bin-packing.
2218       return true;
2219     if (Left.is(tok::l_brace) && Line.Level == 0 &&
2220         (Line.startsWith(tok::kw_enum) ||
2221          Line.startsWith(tok::kw_export, tok::kw_enum)))
2222       // JavaScript top-level enum key/value pairs are put on separate lines
2223       // instead of bin-packing.
2224       return true;
2225     if (Right.is(tok::r_brace) && Left.is(tok::l_brace) &&
2226         !Left.Children.empty())
2227       // Support AllowShortFunctionsOnASingleLine for JavaScript.
2228       return Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_None ||
2229              Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_Empty ||
2230              (Left.NestingLevel == 0 && Line.Level == 0 &&
2231               Style.AllowShortFunctionsOnASingleLine ==
2232                   FormatStyle::SFS_Inline);
2233   } else if (Style.Language == FormatStyle::LK_Java) {
2234     if (Right.is(tok::plus) && Left.is(tok::string_literal) && Right.Next &&
2235         Right.Next->is(tok::string_literal))
2236       return true;
2237   }
2238 
2239   // If the last token before a '}' is a comma or a trailing comment, the
2240   // intention is to insert a line break after it in order to make shuffling
2241   // around entries easier.
2242   const FormatToken *BeforeClosingBrace = nullptr;
2243   if (Left.isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) &&
2244       Left.BlockKind != BK_Block && Left.MatchingParen)
2245     BeforeClosingBrace = Left.MatchingParen->Previous;
2246   else if (Right.MatchingParen &&
2247            Right.MatchingParen->isOneOf(tok::l_brace,
2248                                         TT_ArrayInitializerLSquare))
2249     BeforeClosingBrace = &Left;
2250   if (BeforeClosingBrace && (BeforeClosingBrace->is(tok::comma) ||
2251                              BeforeClosingBrace->isTrailingComment()))
2252     return true;
2253 
2254   if (Right.is(tok::comment))
2255     return Left.BlockKind != BK_BracedInit &&
2256            Left.isNot(TT_CtorInitializerColon) &&
2257            (Right.NewlinesBefore > 0 && Right.HasUnescapedNewline);
2258   if (Left.isTrailingComment())
2259     return true;
2260   if (Left.isStringLiteral() &&
2261       (Right.isStringLiteral() || Right.is(TT_ObjCStringLiteral)))
2262     return true;
2263   if (Right.Previous->IsUnterminatedLiteral)
2264     return true;
2265   if (Right.is(tok::lessless) && Right.Next &&
2266       Right.Previous->is(tok::string_literal) &&
2267       Right.Next->is(tok::string_literal))
2268     return true;
2269   if (Right.Previous->ClosesTemplateDeclaration &&
2270       Right.Previous->MatchingParen &&
2271       Right.Previous->MatchingParen->NestingLevel == 0 &&
2272       Style.AlwaysBreakTemplateDeclarations)
2273     return true;
2274   if ((Right.isOneOf(TT_CtorInitializerComma, TT_CtorInitializerColon)) &&
2275       Style.BreakConstructorInitializersBeforeComma &&
2276       !Style.ConstructorInitializerAllOnOneLineOrOnePerLine)
2277     return true;
2278   if (Right.is(tok::string_literal) && Right.TokenText.startswith("R\""))
2279     // Raw string literals are special wrt. line breaks. The author has made a
2280     // deliberate choice and might have aligned the contents of the string
2281     // literal accordingly. Thus, we try keep existing line breaks.
2282     return Right.NewlinesBefore > 0;
2283   if (Right.Previous->is(tok::l_brace) && Right.NestingLevel == 1 &&
2284       Style.Language == FormatStyle::LK_Proto)
2285     // Don't put enums onto single lines in protocol buffers.
2286     return true;
2287   if (Right.is(TT_InlineASMBrace))
2288     return Right.HasUnescapedNewline;
2289   if (isAllmanBrace(Left) || isAllmanBrace(Right))
2290     return (Line.startsWith(tok::kw_enum) && Style.BraceWrapping.AfterEnum) ||
2291            (Line.startsWith(tok::kw_class) && Style.BraceWrapping.AfterClass) ||
2292            (Line.startsWith(tok::kw_struct) && Style.BraceWrapping.AfterStruct);
2293   if (Style.Language == FormatStyle::LK_Proto && Left.isNot(tok::l_brace) &&
2294       Right.is(TT_SelectorName))
2295     return true;
2296   if (Left.is(TT_ObjCBlockLBrace) && !Style.AllowShortBlocksOnASingleLine)
2297     return true;
2298 
2299   if ((Style.Language == FormatStyle::LK_Java ||
2300        Style.Language == FormatStyle::LK_JavaScript) &&
2301       Left.is(TT_LeadingJavaAnnotation) &&
2302       Right.isNot(TT_LeadingJavaAnnotation) && Right.isNot(tok::l_paren) &&
2303       (Line.Last->is(tok::l_brace) || Style.BreakAfterJavaFieldAnnotations))
2304     return true;
2305 
2306   return false;
2307 }
2308 
2309 bool TokenAnnotator::canBreakBefore(const AnnotatedLine &Line,
2310                                     const FormatToken &Right) {
2311   const FormatToken &Left = *Right.Previous;
2312 
2313   // Language-specific stuff.
2314   if (Style.Language == FormatStyle::LK_Java) {
2315     if (Left.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
2316                      Keywords.kw_implements))
2317       return false;
2318     if (Right.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
2319                       Keywords.kw_implements))
2320       return true;
2321   } else if (Style.Language == FormatStyle::LK_JavaScript) {
2322     if (Left.is(tok::kw_return))
2323       return false; // Otherwise a semicolon is inserted.
2324     if (Left.is(TT_JsFatArrow) && Right.is(tok::l_brace))
2325       return false;
2326     if (Left.is(TT_JsTypeColon))
2327       return true;
2328     if (Right.NestingLevel == 0 && Right.is(Keywords.kw_is))
2329       return false;
2330     if (Left.is(Keywords.kw_in))
2331       return Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None;
2332     if (Right.is(Keywords.kw_in))
2333       return Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None;
2334   }
2335 
2336   if (Left.is(tok::at))
2337     return false;
2338   if (Left.Tok.getObjCKeywordID() == tok::objc_interface)
2339     return false;
2340   if (Left.isOneOf(TT_JavaAnnotation, TT_LeadingJavaAnnotation))
2341     return !Right.is(tok::l_paren);
2342   if (Right.is(TT_PointerOrReference))
2343     return Line.IsMultiVariableDeclStmt ||
2344            (Style.PointerAlignment == FormatStyle::PAS_Right &&
2345             (!Right.Next || Right.Next->isNot(TT_FunctionDeclarationName)));
2346   if (Right.isOneOf(TT_StartOfName, TT_FunctionDeclarationName) ||
2347       Right.is(tok::kw_operator))
2348     return true;
2349   if (Left.is(TT_PointerOrReference))
2350     return false;
2351   if (Right.isTrailingComment())
2352     // We rely on MustBreakBefore being set correctly here as we should not
2353     // change the "binding" behavior of a comment.
2354     // The first comment in a braced lists is always interpreted as belonging to
2355     // the first list element. Otherwise, it should be placed outside of the
2356     // list.
2357     return Left.BlockKind == BK_BracedInit;
2358   if (Left.is(tok::question) && Right.is(tok::colon))
2359     return false;
2360   if (Right.is(TT_ConditionalExpr) || Right.is(tok::question))
2361     return Style.BreakBeforeTernaryOperators;
2362   if (Left.is(TT_ConditionalExpr) || Left.is(tok::question))
2363     return !Style.BreakBeforeTernaryOperators;
2364   if (Right.is(TT_InheritanceColon))
2365     return true;
2366   if (Right.is(tok::colon) &&
2367       !Right.isOneOf(TT_CtorInitializerColon, TT_InlineASMColon))
2368     return false;
2369   if (Left.is(tok::colon) && (Left.isOneOf(TT_DictLiteral, TT_ObjCMethodExpr)))
2370     return true;
2371   if (Right.is(TT_SelectorName) || (Right.is(tok::identifier) && Right.Next &&
2372                                     Right.Next->is(TT_ObjCMethodExpr)))
2373     return Left.isNot(tok::period); // FIXME: Properly parse ObjC calls.
2374   if (Left.is(tok::r_paren) && Line.Type == LT_ObjCProperty)
2375     return true;
2376   if (Left.ClosesTemplateDeclaration || Left.is(TT_FunctionAnnotationRParen))
2377     return true;
2378   if (Right.isOneOf(TT_RangeBasedForLoopColon, TT_OverloadedOperatorLParen,
2379                     TT_OverloadedOperator))
2380     return false;
2381   if (Left.is(TT_RangeBasedForLoopColon))
2382     return true;
2383   if (Right.is(TT_RangeBasedForLoopColon))
2384     return false;
2385   if (Left.isOneOf(TT_TemplateCloser, TT_UnaryOperator) ||
2386       Left.is(tok::kw_operator))
2387     return false;
2388   if (Left.is(tok::equal) && !Right.isOneOf(tok::kw_default, tok::kw_delete) &&
2389       Line.Type == LT_VirtualFunctionDecl && Left.NestingLevel == 0)
2390     return false;
2391   if (Left.is(tok::l_paren) && Left.is(TT_AttributeParen))
2392     return false;
2393   if (Left.is(tok::l_paren) && Left.Previous &&
2394       (Left.Previous->isOneOf(TT_BinaryOperator, TT_CastRParen)))
2395     return false;
2396   if (Right.is(TT_ImplicitStringLiteral))
2397     return false;
2398 
2399   if (Right.is(tok::r_paren) || Right.is(TT_TemplateCloser))
2400     return false;
2401   if (Right.is(tok::r_square) && Right.MatchingParen &&
2402       Right.MatchingParen->is(TT_LambdaLSquare))
2403     return false;
2404 
2405   // We only break before r_brace if there was a corresponding break before
2406   // the l_brace, which is tracked by BreakBeforeClosingBrace.
2407   if (Right.is(tok::r_brace))
2408     return Right.MatchingParen && Right.MatchingParen->BlockKind == BK_Block;
2409 
2410   // Allow breaking after a trailing annotation, e.g. after a method
2411   // declaration.
2412   if (Left.is(TT_TrailingAnnotation))
2413     return !Right.isOneOf(tok::l_brace, tok::semi, tok::equal, tok::l_paren,
2414                           tok::less, tok::coloncolon);
2415 
2416   if (Right.is(tok::kw___attribute))
2417     return true;
2418 
2419   if (Left.is(tok::identifier) && Right.is(tok::string_literal))
2420     return true;
2421 
2422   if (Right.is(tok::identifier) && Right.Next && Right.Next->is(TT_DictLiteral))
2423     return true;
2424 
2425   if (Left.is(TT_CtorInitializerComma) &&
2426       Style.BreakConstructorInitializersBeforeComma)
2427     return false;
2428   if (Right.is(TT_CtorInitializerComma) &&
2429       Style.BreakConstructorInitializersBeforeComma)
2430     return true;
2431   if ((Left.is(tok::greater) && Right.is(tok::greater)) ||
2432       (Left.is(tok::less) && Right.is(tok::less)))
2433     return false;
2434   if (Right.is(TT_BinaryOperator) &&
2435       Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None &&
2436       (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_All ||
2437        Right.getPrecedence() != prec::Assignment))
2438     return true;
2439   if (Left.is(TT_ArrayInitializerLSquare))
2440     return true;
2441   if (Right.is(tok::kw_typename) && Left.isNot(tok::kw_const))
2442     return true;
2443   if ((Left.isBinaryOperator() || Left.is(TT_BinaryOperator)) &&
2444       !Left.isOneOf(tok::arrowstar, tok::lessless) &&
2445       Style.BreakBeforeBinaryOperators != FormatStyle::BOS_All &&
2446       (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None ||
2447        Left.getPrecedence() == prec::Assignment))
2448     return true;
2449   return Left.isOneOf(tok::comma, tok::coloncolon, tok::semi, tok::l_brace,
2450                       tok::kw_class, tok::kw_struct) ||
2451          Right.isMemberAccess() ||
2452          Right.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow, tok::lessless,
2453                        tok::colon, tok::l_square, tok::at) ||
2454          (Left.is(tok::r_paren) &&
2455           Right.isOneOf(tok::identifier, tok::kw_const)) ||
2456          (Left.is(tok::l_paren) && !Right.is(tok::r_paren));
2457 }
2458 
2459 void TokenAnnotator::printDebugInfo(const AnnotatedLine &Line) {
2460   llvm::errs() << "AnnotatedTokens:\n";
2461   const FormatToken *Tok = Line.First;
2462   while (Tok) {
2463     llvm::errs() << " M=" << Tok->MustBreakBefore
2464                  << " C=" << Tok->CanBreakBefore
2465                  << " T=" << getTokenTypeName(Tok->Type)
2466                  << " S=" << Tok->SpacesRequiredBefore
2467                  << " B=" << Tok->BlockParameterCount
2468                  << " P=" << Tok->SplitPenalty << " Name=" << Tok->Tok.getName()
2469                  << " L=" << Tok->TotalLength << " PPK=" << Tok->PackingKind
2470                  << " FakeLParens=";
2471     for (unsigned i = 0, e = Tok->FakeLParens.size(); i != e; ++i)
2472       llvm::errs() << Tok->FakeLParens[i] << "/";
2473     llvm::errs() << " FakeRParens=" << Tok->FakeRParens << "\n";
2474     if (!Tok->Next)
2475       assert(Tok == Line.Last);
2476     Tok = Tok->Next;
2477   }
2478   llvm::errs() << "----\n";
2479 }
2480 
2481 } // namespace format
2482 } // namespace clang
2483