1 //===--- TokenAnnotator.cpp - Format C++ code -----------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// This file implements a token annotator, i.e. creates
11 /// \c AnnotatedTokens out of \c FormatTokens with required extra information.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #include "TokenAnnotator.h"
16 #include "clang/Basic/SourceManager.h"
17 #include "llvm/ADT/SmallPtrSet.h"
18 #include "llvm/Support/Debug.h"
19 
20 #define DEBUG_TYPE "format-token-annotator"
21 
22 namespace clang {
23 namespace format {
24 
25 namespace {
26 
27 /// Returns \c true if the token can be used as an identifier in
28 /// an Objective-C \c @selector, \c false otherwise.
29 ///
30 /// Because getFormattingLangOpts() always lexes source code as
31 /// Objective-C++, C++ keywords like \c new and \c delete are
32 /// lexed as tok::kw_*, not tok::identifier, even for Objective-C.
33 ///
34 /// For Objective-C and Objective-C++, both identifiers and keywords
35 /// are valid inside @selector(...) (or a macro which
36 /// invokes @selector(...)). So, we allow treat any identifier or
37 /// keyword as a potential Objective-C selector component.
38 static bool canBeObjCSelectorComponent(const FormatToken &Tok) {
39   return Tok.Tok.getIdentifierInfo() != nullptr;
40 }
41 
42 /// A parser that gathers additional information about tokens.
43 ///
44 /// The \c TokenAnnotator tries to match parenthesis and square brakets and
45 /// store a parenthesis levels. It also tries to resolve matching "<" and ">"
46 /// into template parameter lists.
47 class AnnotatingParser {
48 public:
49   AnnotatingParser(const FormatStyle &Style, AnnotatedLine &Line,
50                    const AdditionalKeywords &Keywords)
51       : Style(Style), Line(Line), CurrentToken(Line.First), AutoFound(false),
52         Keywords(Keywords) {
53     Contexts.push_back(Context(tok::unknown, 1, /*IsExpression=*/false));
54     resetTokenMetadata(CurrentToken);
55   }
56 
57 private:
58   bool parseAngle() {
59     if (!CurrentToken || !CurrentToken->Previous)
60       return false;
61     if (NonTemplateLess.count(CurrentToken->Previous))
62       return false;
63 
64     const FormatToken &Previous = *CurrentToken->Previous; // The '<'.
65     if (Previous.Previous) {
66       if (Previous.Previous->Tok.isLiteral())
67         return false;
68       if (Previous.Previous->is(tok::r_paren) && Contexts.size() > 1 &&
69           (!Previous.Previous->MatchingParen ||
70            !Previous.Previous->MatchingParen->is(TT_OverloadedOperatorLParen)))
71         return false;
72     }
73 
74     FormatToken *Left = CurrentToken->Previous;
75     Left->ParentBracket = Contexts.back().ContextKind;
76     ScopedContextCreator ContextCreator(*this, tok::less, 12);
77 
78     // If this angle is in the context of an expression, we need to be more
79     // hesitant to detect it as opening template parameters.
80     bool InExprContext = Contexts.back().IsExpression;
81 
82     Contexts.back().IsExpression = false;
83     // If there's a template keyword before the opening angle bracket, this is a
84     // template parameter, not an argument.
85     Contexts.back().InTemplateArgument =
86         Left->Previous && Left->Previous->Tok.isNot(tok::kw_template);
87 
88     if (Style.Language == FormatStyle::LK_Java &&
89         CurrentToken->is(tok::question))
90       next();
91 
92     while (CurrentToken) {
93       if (CurrentToken->is(tok::greater)) {
94         Left->MatchingParen = CurrentToken;
95         CurrentToken->MatchingParen = Left;
96         // In TT_Proto, we must distignuish between:
97         //   map<key, value>
98         //   msg < item: data >
99         //   msg: < item: data >
100         // In TT_TextProto, map<key, value> does not occur.
101         if (Style.Language == FormatStyle::LK_TextProto ||
102             (Style.Language == FormatStyle::LK_Proto && Left->Previous &&
103              Left->Previous->isOneOf(TT_SelectorName, TT_DictLiteral)))
104           CurrentToken->Type = TT_DictLiteral;
105         else
106           CurrentToken->Type = TT_TemplateCloser;
107         next();
108         return true;
109       }
110       if (CurrentToken->is(tok::question) &&
111           Style.Language == FormatStyle::LK_Java) {
112         next();
113         continue;
114       }
115       if (CurrentToken->isOneOf(tok::r_paren, tok::r_square, tok::r_brace) ||
116           (CurrentToken->isOneOf(tok::colon, tok::question) && InExprContext &&
117            Style.Language != FormatStyle::LK_Proto &&
118            Style.Language != FormatStyle::LK_TextProto))
119         return false;
120       // If a && or || is found and interpreted as a binary operator, this set
121       // of angles is likely part of something like "a < b && c > d". If the
122       // angles are inside an expression, the ||/&& might also be a binary
123       // operator that was misinterpreted because we are parsing template
124       // parameters.
125       // FIXME: This is getting out of hand, write a decent parser.
126       if (CurrentToken->Previous->isOneOf(tok::pipepipe, tok::ampamp) &&
127           CurrentToken->Previous->is(TT_BinaryOperator) &&
128           Contexts[Contexts.size() - 2].IsExpression &&
129           !Line.startsWith(tok::kw_template))
130         return false;
131       updateParameterCount(Left, CurrentToken);
132       if (Style.Language == FormatStyle::LK_Proto) {
133         if (FormatToken *Previous = CurrentToken->getPreviousNonComment()) {
134           if (CurrentToken->is(tok::colon) ||
135               (CurrentToken->isOneOf(tok::l_brace, tok::less) &&
136                Previous->isNot(tok::colon)))
137             Previous->Type = TT_SelectorName;
138         }
139       }
140       if (!consumeToken())
141         return false;
142     }
143     return false;
144   }
145 
146   bool parseParens(bool LookForDecls = false) {
147     if (!CurrentToken)
148       return false;
149     FormatToken *Left = CurrentToken->Previous;
150     Left->ParentBracket = Contexts.back().ContextKind;
151     ScopedContextCreator ContextCreator(*this, tok::l_paren, 1);
152 
153     // FIXME: This is a bit of a hack. Do better.
154     Contexts.back().ColonIsForRangeExpr =
155         Contexts.size() == 2 && Contexts[0].ColonIsForRangeExpr;
156 
157     bool StartsObjCMethodExpr = false;
158     if (FormatToken *MaybeSel = Left->Previous) {
159       // @selector( starts a selector.
160       if (MaybeSel->isObjCAtKeyword(tok::objc_selector) && MaybeSel->Previous &&
161           MaybeSel->Previous->is(tok::at)) {
162         StartsObjCMethodExpr = true;
163       }
164     }
165 
166     if (Left->is(TT_OverloadedOperatorLParen)) {
167       Contexts.back().IsExpression = false;
168     } else if (Style.Language == FormatStyle::LK_JavaScript &&
169                (Line.startsWith(Keywords.kw_type, tok::identifier) ||
170                 Line.startsWith(tok::kw_export, Keywords.kw_type,
171                                 tok::identifier))) {
172       // type X = (...);
173       // export type X = (...);
174       Contexts.back().IsExpression = false;
175     } else if (Left->Previous &&
176                (Left->Previous->isOneOf(tok::kw_static_assert, tok::kw_decltype,
177                                         tok::kw_if, tok::kw_while, tok::l_paren,
178                                         tok::comma) ||
179                 Left->Previous->endsSequence(tok::kw_constexpr, tok::kw_if) ||
180                 Left->Previous->is(TT_BinaryOperator))) {
181       // static_assert, if and while usually contain expressions.
182       Contexts.back().IsExpression = true;
183     } else if (Style.Language == FormatStyle::LK_JavaScript && Left->Previous &&
184                (Left->Previous->is(Keywords.kw_function) ||
185                 (Left->Previous->endsSequence(tok::identifier,
186                                               Keywords.kw_function)))) {
187       // function(...) or function f(...)
188       Contexts.back().IsExpression = false;
189     } else if (Style.Language == FormatStyle::LK_JavaScript && Left->Previous &&
190                Left->Previous->is(TT_JsTypeColon)) {
191       // let x: (SomeType);
192       Contexts.back().IsExpression = false;
193     } else if (Left->Previous && Left->Previous->is(tok::r_square) &&
194                Left->Previous->MatchingParen &&
195                Left->Previous->MatchingParen->is(TT_LambdaLSquare)) {
196       // This is a parameter list of a lambda expression.
197       Contexts.back().IsExpression = false;
198     } else if (Line.InPPDirective &&
199                (!Left->Previous || !Left->Previous->is(tok::identifier))) {
200       Contexts.back().IsExpression = true;
201     } else if (Contexts[Contexts.size() - 2].CaretFound) {
202       // This is the parameter list of an ObjC block.
203       Contexts.back().IsExpression = false;
204     } else if (Left->Previous && Left->Previous->is(tok::kw___attribute)) {
205       Left->Type = TT_AttributeParen;
206     } else if (Left->Previous && Left->Previous->is(TT_ForEachMacro)) {
207       // The first argument to a foreach macro is a declaration.
208       Contexts.back().IsForEachMacro = true;
209       Contexts.back().IsExpression = false;
210     } else if (Left->Previous && Left->Previous->MatchingParen &&
211                Left->Previous->MatchingParen->is(TT_ObjCBlockLParen)) {
212       Contexts.back().IsExpression = false;
213     } else if (!Line.MustBeDeclaration && !Line.InPPDirective) {
214       bool IsForOrCatch =
215           Left->Previous && Left->Previous->isOneOf(tok::kw_for, tok::kw_catch);
216       Contexts.back().IsExpression = !IsForOrCatch;
217     }
218 
219     if (StartsObjCMethodExpr) {
220       Contexts.back().ColonIsObjCMethodExpr = true;
221       Left->Type = TT_ObjCMethodExpr;
222     }
223 
224     // MightBeFunctionType and ProbablyFunctionType are used for
225     // function pointer and reference types as well as Objective-C
226     // block types:
227     //
228     // void (*FunctionPointer)(void);
229     // void (&FunctionReference)(void);
230     // void (^ObjCBlock)(void);
231     bool MightBeFunctionType = !Contexts[Contexts.size() - 2].IsExpression;
232     bool ProbablyFunctionType =
233         CurrentToken->isOneOf(tok::star, tok::amp, tok::caret);
234     bool HasMultipleLines = false;
235     bool HasMultipleParametersOnALine = false;
236     bool MightBeObjCForRangeLoop =
237         Left->Previous && Left->Previous->is(tok::kw_for);
238     FormatToken *PossibleObjCForInToken = nullptr;
239     while (CurrentToken) {
240       // LookForDecls is set when "if (" has been seen. Check for
241       // 'identifier' '*' 'identifier' followed by not '=' -- this
242       // '*' has to be a binary operator but determineStarAmpUsage() will
243       // categorize it as an unary operator, so set the right type here.
244       if (LookForDecls && CurrentToken->Next) {
245         FormatToken *Prev = CurrentToken->getPreviousNonComment();
246         if (Prev) {
247           FormatToken *PrevPrev = Prev->getPreviousNonComment();
248           FormatToken *Next = CurrentToken->Next;
249           if (PrevPrev && PrevPrev->is(tok::identifier) &&
250               Prev->isOneOf(tok::star, tok::amp, tok::ampamp) &&
251               CurrentToken->is(tok::identifier) && Next->isNot(tok::equal)) {
252             Prev->Type = TT_BinaryOperator;
253             LookForDecls = false;
254           }
255         }
256       }
257 
258       if (CurrentToken->Previous->is(TT_PointerOrReference) &&
259           CurrentToken->Previous->Previous->isOneOf(tok::l_paren,
260                                                     tok::coloncolon))
261         ProbablyFunctionType = true;
262       if (CurrentToken->is(tok::comma))
263         MightBeFunctionType = false;
264       if (CurrentToken->Previous->is(TT_BinaryOperator))
265         Contexts.back().IsExpression = true;
266       if (CurrentToken->is(tok::r_paren)) {
267         if (MightBeFunctionType && ProbablyFunctionType && CurrentToken->Next &&
268             (CurrentToken->Next->is(tok::l_paren) ||
269              (CurrentToken->Next->is(tok::l_square) && Line.MustBeDeclaration)))
270           Left->Type = Left->Next->is(tok::caret) ? TT_ObjCBlockLParen
271                                                   : TT_FunctionTypeLParen;
272         Left->MatchingParen = CurrentToken;
273         CurrentToken->MatchingParen = Left;
274 
275         if (CurrentToken->Next && CurrentToken->Next->is(tok::l_brace) &&
276             Left->Previous && Left->Previous->is(tok::l_paren)) {
277           // Detect the case where macros are used to generate lambdas or
278           // function bodies, e.g.:
279           //   auto my_lambda = MARCO((Type *type, int i) { .. body .. });
280           for (FormatToken *Tok = Left; Tok != CurrentToken; Tok = Tok->Next) {
281             if (Tok->is(TT_BinaryOperator) &&
282                 Tok->isOneOf(tok::star, tok::amp, tok::ampamp))
283               Tok->Type = TT_PointerOrReference;
284           }
285         }
286 
287         if (StartsObjCMethodExpr) {
288           CurrentToken->Type = TT_ObjCMethodExpr;
289           if (Contexts.back().FirstObjCSelectorName) {
290             Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
291                 Contexts.back().LongestObjCSelectorName;
292           }
293         }
294 
295         if (Left->is(TT_AttributeParen))
296           CurrentToken->Type = TT_AttributeParen;
297         if (Left->Previous && Left->Previous->is(TT_JavaAnnotation))
298           CurrentToken->Type = TT_JavaAnnotation;
299         if (Left->Previous && Left->Previous->is(TT_LeadingJavaAnnotation))
300           CurrentToken->Type = TT_LeadingJavaAnnotation;
301         if (Left->Previous && Left->Previous->is(TT_AttributeSquare))
302           CurrentToken->Type = TT_AttributeSquare;
303 
304         if (!HasMultipleLines)
305           Left->PackingKind = PPK_Inconclusive;
306         else if (HasMultipleParametersOnALine)
307           Left->PackingKind = PPK_BinPacked;
308         else
309           Left->PackingKind = PPK_OnePerLine;
310 
311         next();
312         return true;
313       }
314       if (CurrentToken->isOneOf(tok::r_square, tok::r_brace))
315         return false;
316 
317       if (CurrentToken->is(tok::l_brace))
318         Left->Type = TT_Unknown; // Not TT_ObjCBlockLParen
319       if (CurrentToken->is(tok::comma) && CurrentToken->Next &&
320           !CurrentToken->Next->HasUnescapedNewline &&
321           !CurrentToken->Next->isTrailingComment())
322         HasMultipleParametersOnALine = true;
323       if ((CurrentToken->Previous->isOneOf(tok::kw_const, tok::kw_auto) ||
324            CurrentToken->Previous->isSimpleTypeSpecifier()) &&
325           !CurrentToken->is(tok::l_brace))
326         Contexts.back().IsExpression = false;
327       if (CurrentToken->isOneOf(tok::semi, tok::colon)) {
328         MightBeObjCForRangeLoop = false;
329         if (PossibleObjCForInToken) {
330           PossibleObjCForInToken->Type = TT_Unknown;
331           PossibleObjCForInToken = nullptr;
332         }
333       }
334       if (MightBeObjCForRangeLoop && CurrentToken->is(Keywords.kw_in)) {
335         PossibleObjCForInToken = CurrentToken;
336         PossibleObjCForInToken->Type = TT_ObjCForIn;
337       }
338       // When we discover a 'new', we set CanBeExpression to 'false' in order to
339       // parse the type correctly. Reset that after a comma.
340       if (CurrentToken->is(tok::comma))
341         Contexts.back().CanBeExpression = true;
342 
343       FormatToken *Tok = CurrentToken;
344       if (!consumeToken())
345         return false;
346       updateParameterCount(Left, Tok);
347       if (CurrentToken && CurrentToken->HasUnescapedNewline)
348         HasMultipleLines = true;
349     }
350     return false;
351   }
352 
353   bool isCSharpAttributeSpecifier(const FormatToken &Tok) {
354     if (!Style.isCSharp())
355       return false;
356 
357     const FormatToken *AttrTok = Tok.Next;
358     if (!AttrTok)
359       return false;
360 
361     // Just an empty declaration e.g. string [].
362     if (AttrTok->is(tok::r_square))
363       return false;
364 
365     // Move along the tokens inbetween the '[' and ']' e.g. [STAThread].
366     while (AttrTok && AttrTok->isNot(tok::r_square)) {
367       AttrTok = AttrTok->Next;
368     }
369 
370     if (!AttrTok)
371       return false;
372 
373     // Move past the end of ']'.
374     AttrTok = AttrTok->Next;
375     if (!AttrTok)
376       return false;
377 
378     // Limit this to being an access modifier that follows.
379     if (AttrTok->isOneOf(tok::kw_public, tok::kw_private, tok::kw_protected,
380                          tok::kw_class, tok::kw_static, tok::l_square,
381                          Keywords.kw_internal)) {
382       return true;
383     }
384     return false;
385   }
386 
387   bool isCpp11AttributeSpecifier(const FormatToken &Tok) {
388     if (!Style.isCpp() || !Tok.startsSequence(tok::l_square, tok::l_square))
389       return false;
390     const FormatToken *AttrTok = Tok.Next->Next;
391     if (!AttrTok)
392       return false;
393     // C++17 '[[using ns: foo, bar(baz, blech)]]'
394     // We assume nobody will name an ObjC variable 'using'.
395     if (AttrTok->startsSequence(tok::kw_using, tok::identifier, tok::colon))
396       return true;
397     if (AttrTok->isNot(tok::identifier))
398       return false;
399     while (AttrTok && !AttrTok->startsSequence(tok::r_square, tok::r_square)) {
400       // ObjC message send. We assume nobody will use : in a C++11 attribute
401       // specifier parameter, although this is technically valid:
402       // [[foo(:)]]
403       if (AttrTok->is(tok::colon) ||
404           AttrTok->startsSequence(tok::identifier, tok::identifier) ||
405           AttrTok->startsSequence(tok::r_paren, tok::identifier))
406         return false;
407       if (AttrTok->is(tok::ellipsis))
408         return true;
409       AttrTok = AttrTok->Next;
410     }
411     return AttrTok && AttrTok->startsSequence(tok::r_square, tok::r_square);
412   }
413 
414   bool parseSquare() {
415     if (!CurrentToken)
416       return false;
417 
418     // A '[' could be an index subscript (after an identifier or after
419     // ')' or ']'), it could be the start of an Objective-C method
420     // expression, it could the start of an Objective-C array literal,
421     // or it could be a C++ attribute specifier [[foo::bar]].
422     FormatToken *Left = CurrentToken->Previous;
423     Left->ParentBracket = Contexts.back().ContextKind;
424     FormatToken *Parent = Left->getPreviousNonComment();
425 
426     // Cases where '>' is followed by '['.
427     // In C++, this can happen either in array of templates (foo<int>[10])
428     // or when array is a nested template type (unique_ptr<type1<type2>[]>).
429     bool CppArrayTemplates =
430         Style.isCpp() && Parent && Parent->is(TT_TemplateCloser) &&
431         (Contexts.back().CanBeExpression || Contexts.back().IsExpression ||
432          Contexts.back().InTemplateArgument);
433 
434     bool IsCpp11AttributeSpecifier = isCpp11AttributeSpecifier(*Left) ||
435                                      Contexts.back().InCpp11AttributeSpecifier;
436 
437     // Treat C# Attributes [STAThread] much like C++ attributes [[...]].
438     bool IsCSharp11AttributeSpecifier =
439         isCSharpAttributeSpecifier(*Left) ||
440         Contexts.back().InCSharpAttributeSpecifier;
441 
442     bool InsideInlineASM = Line.startsWith(tok::kw_asm);
443     bool StartsObjCMethodExpr =
444         !InsideInlineASM && !CppArrayTemplates && Style.isCpp() &&
445         !IsCpp11AttributeSpecifier && Contexts.back().CanBeExpression &&
446         Left->isNot(TT_LambdaLSquare) &&
447         !CurrentToken->isOneOf(tok::l_brace, tok::r_square) &&
448         (!Parent ||
449          Parent->isOneOf(tok::colon, tok::l_square, tok::l_paren,
450                          tok::kw_return, tok::kw_throw) ||
451          Parent->isUnaryOperator() ||
452          // FIXME(bug 36976): ObjC return types shouldn't use TT_CastRParen.
453          Parent->isOneOf(TT_ObjCForIn, TT_CastRParen) ||
454          // for (auto && [A,B] : C)  && structure binding seen as ObjCMethodExpr
455          (Parent->isNot(tok::ampamp) &&
456           getBinOpPrecedence(Parent->Tok.getKind(), true, true) >
457               prec::Unknown));
458     bool ColonFound = false;
459 
460     unsigned BindingIncrease = 1;
461     if (Left->isCppStructuredBinding(Style)) {
462       Left->Type = TT_StructuredBindingLSquare;
463     } else if (Left->is(TT_Unknown)) {
464       if (StartsObjCMethodExpr) {
465         Left->Type = TT_ObjCMethodExpr;
466       } else if (IsCpp11AttributeSpecifier) {
467         Left->Type = TT_AttributeSquare;
468       } else if (Style.Language == FormatStyle::LK_JavaScript && Parent &&
469                  Contexts.back().ContextKind == tok::l_brace &&
470                  Parent->isOneOf(tok::l_brace, tok::comma)) {
471         Left->Type = TT_JsComputedPropertyName;
472       } else if (Style.isCpp() && Contexts.back().ContextKind == tok::l_brace &&
473                  Parent && Parent->isOneOf(tok::l_brace, tok::comma)) {
474         Left->Type = TT_DesignatedInitializerLSquare;
475       } else if (CurrentToken->is(tok::r_square) && Parent &&
476                  Parent->is(TT_TemplateCloser)) {
477         Left->Type = TT_ArraySubscriptLSquare;
478       } else if (Style.Language == FormatStyle::LK_Proto ||
479                  Style.Language == FormatStyle::LK_TextProto) {
480         // Square braces in LK_Proto can either be message field attributes:
481         //
482         // optional Aaa aaa = 1 [
483         //   (aaa) = aaa
484         // ];
485         //
486         // extensions 123 [
487         //   (aaa) = aaa
488         // ];
489         //
490         // or text proto extensions (in options):
491         //
492         // option (Aaa.options) = {
493         //   [type.type/type] {
494         //     key: value
495         //   }
496         // }
497         //
498         // or repeated fields (in options):
499         //
500         // option (Aaa.options) = {
501         //   keys: [ 1, 2, 3 ]
502         // }
503         //
504         // In the first and the third case we want to spread the contents inside
505         // the square braces; in the second we want to keep them inline.
506         Left->Type = TT_ArrayInitializerLSquare;
507         if (!Left->endsSequence(tok::l_square, tok::numeric_constant,
508                                 tok::equal) &&
509             !Left->endsSequence(tok::l_square, tok::numeric_constant,
510                                 tok::identifier) &&
511             !Left->endsSequence(tok::l_square, tok::colon, TT_SelectorName)) {
512           Left->Type = TT_ProtoExtensionLSquare;
513           BindingIncrease = 10;
514         }
515       } else if (!CppArrayTemplates && Parent &&
516                  Parent->isOneOf(TT_BinaryOperator, TT_TemplateCloser, tok::at,
517                                  tok::comma, tok::l_paren, tok::l_square,
518                                  tok::question, tok::colon, tok::kw_return,
519                                  // Should only be relevant to JavaScript:
520                                  tok::kw_default)) {
521         Left->Type = TT_ArrayInitializerLSquare;
522       } else if (IsCSharp11AttributeSpecifier) {
523         Left->Type = TT_AttributeSquare;
524       } else {
525         BindingIncrease = 10;
526         Left->Type = TT_ArraySubscriptLSquare;
527       }
528     }
529 
530     ScopedContextCreator ContextCreator(*this, tok::l_square, BindingIncrease);
531     Contexts.back().IsExpression = true;
532     if (Style.Language == FormatStyle::LK_JavaScript && Parent &&
533         Parent->is(TT_JsTypeColon))
534       Contexts.back().IsExpression = false;
535 
536     Contexts.back().ColonIsObjCMethodExpr = StartsObjCMethodExpr;
537     Contexts.back().InCpp11AttributeSpecifier = IsCpp11AttributeSpecifier;
538     Contexts.back().InCSharpAttributeSpecifier = IsCSharp11AttributeSpecifier;
539 
540     while (CurrentToken) {
541       if (CurrentToken->is(tok::r_square)) {
542         if (IsCpp11AttributeSpecifier)
543           CurrentToken->Type = TT_AttributeSquare;
544         if (IsCSharp11AttributeSpecifier)
545           CurrentToken->Type = TT_AttributeSquare;
546         else if (((CurrentToken->Next &&
547                    CurrentToken->Next->is(tok::l_paren)) ||
548                   (CurrentToken->Previous &&
549                    CurrentToken->Previous->Previous == Left)) &&
550                  Left->is(TT_ObjCMethodExpr)) {
551           // An ObjC method call is rarely followed by an open parenthesis. It
552           // also can't be composed of just one token, unless it's a macro that
553           // will be expanded to more tokens.
554           // FIXME: Do we incorrectly label ":" with this?
555           StartsObjCMethodExpr = false;
556           Left->Type = TT_Unknown;
557         }
558         if (StartsObjCMethodExpr && CurrentToken->Previous != Left) {
559           CurrentToken->Type = TT_ObjCMethodExpr;
560           // If we haven't seen a colon yet, make sure the last identifier
561           // before the r_square is tagged as a selector name component.
562           if (!ColonFound && CurrentToken->Previous &&
563               CurrentToken->Previous->is(TT_Unknown) &&
564               canBeObjCSelectorComponent(*CurrentToken->Previous))
565             CurrentToken->Previous->Type = TT_SelectorName;
566           // determineStarAmpUsage() thinks that '*' '[' is allocating an
567           // array of pointers, but if '[' starts a selector then '*' is a
568           // binary operator.
569           if (Parent && Parent->is(TT_PointerOrReference))
570             Parent->Type = TT_BinaryOperator;
571         }
572         // An arrow after an ObjC method expression is not a lambda arrow.
573         if (CurrentToken->Type == TT_ObjCMethodExpr && CurrentToken->Next &&
574             CurrentToken->Next->is(TT_LambdaArrow))
575           CurrentToken->Next->Type = TT_Unknown;
576         Left->MatchingParen = CurrentToken;
577         CurrentToken->MatchingParen = Left;
578         // FirstObjCSelectorName is set when a colon is found. This does
579         // not work, however, when the method has no parameters.
580         // Here, we set FirstObjCSelectorName when the end of the method call is
581         // reached, in case it was not set already.
582         if (!Contexts.back().FirstObjCSelectorName) {
583           FormatToken *Previous = CurrentToken->getPreviousNonComment();
584           if (Previous && Previous->is(TT_SelectorName)) {
585             Previous->ObjCSelectorNameParts = 1;
586             Contexts.back().FirstObjCSelectorName = Previous;
587           }
588         } else {
589           Left->ParameterCount =
590               Contexts.back().FirstObjCSelectorName->ObjCSelectorNameParts;
591         }
592         if (Contexts.back().FirstObjCSelectorName) {
593           Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
594               Contexts.back().LongestObjCSelectorName;
595           if (Left->BlockParameterCount > 1)
596             Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName = 0;
597         }
598         next();
599         return true;
600       }
601       if (CurrentToken->isOneOf(tok::r_paren, tok::r_brace))
602         return false;
603       if (CurrentToken->is(tok::colon)) {
604         if (IsCpp11AttributeSpecifier &&
605             CurrentToken->endsSequence(tok::colon, tok::identifier,
606                                        tok::kw_using)) {
607           // Remember that this is a [[using ns: foo]] C++ attribute, so we
608           // don't add a space before the colon (unlike other colons).
609           CurrentToken->Type = TT_AttributeColon;
610         } else if (Left->isOneOf(TT_ArraySubscriptLSquare,
611                                  TT_DesignatedInitializerLSquare)) {
612           Left->Type = TT_ObjCMethodExpr;
613           StartsObjCMethodExpr = true;
614           Contexts.back().ColonIsObjCMethodExpr = true;
615           if (Parent && Parent->is(tok::r_paren))
616             // FIXME(bug 36976): ObjC return types shouldn't use TT_CastRParen.
617             Parent->Type = TT_CastRParen;
618         }
619         ColonFound = true;
620       }
621       if (CurrentToken->is(tok::comma) && Left->is(TT_ObjCMethodExpr) &&
622           !ColonFound)
623         Left->Type = TT_ArrayInitializerLSquare;
624       FormatToken *Tok = CurrentToken;
625       if (!consumeToken())
626         return false;
627       updateParameterCount(Left, Tok);
628     }
629     return false;
630   }
631 
632   bool parseBrace() {
633     if (CurrentToken) {
634       FormatToken *Left = CurrentToken->Previous;
635       Left->ParentBracket = Contexts.back().ContextKind;
636 
637       if (Contexts.back().CaretFound)
638         Left->Type = TT_ObjCBlockLBrace;
639       Contexts.back().CaretFound = false;
640 
641       ScopedContextCreator ContextCreator(*this, tok::l_brace, 1);
642       Contexts.back().ColonIsDictLiteral = true;
643       if (Left->BlockKind == BK_BracedInit)
644         Contexts.back().IsExpression = true;
645       if (Style.Language == FormatStyle::LK_JavaScript && Left->Previous &&
646           Left->Previous->is(TT_JsTypeColon))
647         Contexts.back().IsExpression = false;
648 
649       while (CurrentToken) {
650         if (CurrentToken->is(tok::r_brace)) {
651           Left->MatchingParen = CurrentToken;
652           CurrentToken->MatchingParen = Left;
653           next();
654           return true;
655         }
656         if (CurrentToken->isOneOf(tok::r_paren, tok::r_square))
657           return false;
658         updateParameterCount(Left, CurrentToken);
659         if (CurrentToken->isOneOf(tok::colon, tok::l_brace, tok::less)) {
660           FormatToken *Previous = CurrentToken->getPreviousNonComment();
661           if (Previous->is(TT_JsTypeOptionalQuestion))
662             Previous = Previous->getPreviousNonComment();
663           if ((CurrentToken->is(tok::colon) &&
664                (!Contexts.back().ColonIsDictLiteral || !Style.isCpp())) ||
665               Style.Language == FormatStyle::LK_Proto ||
666               Style.Language == FormatStyle::LK_TextProto) {
667             Left->Type = TT_DictLiteral;
668             if (Previous->Tok.getIdentifierInfo() ||
669                 Previous->is(tok::string_literal))
670               Previous->Type = TT_SelectorName;
671           }
672           if (CurrentToken->is(tok::colon) ||
673               Style.Language == FormatStyle::LK_JavaScript)
674             Left->Type = TT_DictLiteral;
675         }
676         if (CurrentToken->is(tok::comma) &&
677             Style.Language == FormatStyle::LK_JavaScript)
678           Left->Type = TT_DictLiteral;
679         if (!consumeToken())
680           return false;
681       }
682     }
683     return true;
684   }
685 
686   void updateParameterCount(FormatToken *Left, FormatToken *Current) {
687     // For ObjC methods, the number of parameters is calculated differently as
688     // method declarations have a different structure (the parameters are not
689     // inside a bracket scope).
690     if (Current->is(tok::l_brace) && Current->BlockKind == BK_Block)
691       ++Left->BlockParameterCount;
692     if (Current->is(tok::comma)) {
693       ++Left->ParameterCount;
694       if (!Left->Role)
695         Left->Role.reset(new CommaSeparatedList(Style));
696       Left->Role->CommaFound(Current);
697     } else if (Left->ParameterCount == 0 && Current->isNot(tok::comment)) {
698       Left->ParameterCount = 1;
699     }
700   }
701 
702   bool parseConditional() {
703     while (CurrentToken) {
704       if (CurrentToken->is(tok::colon)) {
705         CurrentToken->Type = TT_ConditionalExpr;
706         next();
707         return true;
708       }
709       if (!consumeToken())
710         return false;
711     }
712     return false;
713   }
714 
715   bool parseTemplateDeclaration() {
716     if (CurrentToken && CurrentToken->is(tok::less)) {
717       CurrentToken->Type = TT_TemplateOpener;
718       next();
719       if (!parseAngle())
720         return false;
721       if (CurrentToken)
722         CurrentToken->Previous->ClosesTemplateDeclaration = true;
723       return true;
724     }
725     return false;
726   }
727 
728   bool consumeToken() {
729     FormatToken *Tok = CurrentToken;
730     next();
731     switch (Tok->Tok.getKind()) {
732     case tok::plus:
733     case tok::minus:
734       if (!Tok->Previous && Line.MustBeDeclaration)
735         Tok->Type = TT_ObjCMethodSpecifier;
736       break;
737     case tok::colon:
738       if (!Tok->Previous)
739         return false;
740       // Colons from ?: are handled in parseConditional().
741       if (Style.Language == FormatStyle::LK_JavaScript) {
742         if (Contexts.back().ColonIsForRangeExpr || // colon in for loop
743             (Contexts.size() == 1 &&               // switch/case labels
744              !Line.First->isOneOf(tok::kw_enum, tok::kw_case)) ||
745             Contexts.back().ContextKind == tok::l_paren ||  // function params
746             Contexts.back().ContextKind == tok::l_square || // array type
747             (!Contexts.back().IsExpression &&
748              Contexts.back().ContextKind == tok::l_brace) || // object type
749             (Contexts.size() == 1 &&
750              Line.MustBeDeclaration)) { // method/property declaration
751           Contexts.back().IsExpression = false;
752           Tok->Type = TT_JsTypeColon;
753           break;
754         }
755       }
756       if (Contexts.back().ColonIsDictLiteral ||
757           Style.Language == FormatStyle::LK_Proto ||
758           Style.Language == FormatStyle::LK_TextProto) {
759         Tok->Type = TT_DictLiteral;
760         if (Style.Language == FormatStyle::LK_TextProto) {
761           if (FormatToken *Previous = Tok->getPreviousNonComment())
762             Previous->Type = TT_SelectorName;
763         }
764       } else if (Contexts.back().ColonIsObjCMethodExpr ||
765                  Line.startsWith(TT_ObjCMethodSpecifier)) {
766         Tok->Type = TT_ObjCMethodExpr;
767         const FormatToken *BeforePrevious = Tok->Previous->Previous;
768         // Ensure we tag all identifiers in method declarations as
769         // TT_SelectorName.
770         bool UnknownIdentifierInMethodDeclaration =
771             Line.startsWith(TT_ObjCMethodSpecifier) &&
772             Tok->Previous->is(tok::identifier) && Tok->Previous->is(TT_Unknown);
773         if (!BeforePrevious ||
774             // FIXME(bug 36976): ObjC return types shouldn't use TT_CastRParen.
775             !(BeforePrevious->is(TT_CastRParen) ||
776               (BeforePrevious->is(TT_ObjCMethodExpr) &&
777                BeforePrevious->is(tok::colon))) ||
778             BeforePrevious->is(tok::r_square) ||
779             Contexts.back().LongestObjCSelectorName == 0 ||
780             UnknownIdentifierInMethodDeclaration) {
781           Tok->Previous->Type = TT_SelectorName;
782           if (!Contexts.back().FirstObjCSelectorName)
783             Contexts.back().FirstObjCSelectorName = Tok->Previous;
784           else if (Tok->Previous->ColumnWidth >
785                    Contexts.back().LongestObjCSelectorName)
786             Contexts.back().LongestObjCSelectorName =
787                 Tok->Previous->ColumnWidth;
788           Tok->Previous->ParameterIndex =
789               Contexts.back().FirstObjCSelectorName->ObjCSelectorNameParts;
790           ++Contexts.back().FirstObjCSelectorName->ObjCSelectorNameParts;
791         }
792       } else if (Contexts.back().ColonIsForRangeExpr) {
793         Tok->Type = TT_RangeBasedForLoopColon;
794       } else if (CurrentToken && CurrentToken->is(tok::numeric_constant)) {
795         Tok->Type = TT_BitFieldColon;
796       } else if (Contexts.size() == 1 &&
797                  !Line.First->isOneOf(tok::kw_enum, tok::kw_case)) {
798         if (Tok->getPreviousNonComment()->isOneOf(tok::r_paren,
799                                                   tok::kw_noexcept))
800           Tok->Type = TT_CtorInitializerColon;
801         else
802           Tok->Type = TT_InheritanceColon;
803       } else if (canBeObjCSelectorComponent(*Tok->Previous) && Tok->Next &&
804                  (Tok->Next->isOneOf(tok::r_paren, tok::comma) ||
805                   (canBeObjCSelectorComponent(*Tok->Next) && Tok->Next->Next &&
806                    Tok->Next->Next->is(tok::colon)))) {
807         // This handles a special macro in ObjC code where selectors including
808         // the colon are passed as macro arguments.
809         Tok->Type = TT_ObjCMethodExpr;
810       } else if (Contexts.back().ContextKind == tok::l_paren) {
811         Tok->Type = TT_InlineASMColon;
812       }
813       break;
814     case tok::pipe:
815     case tok::amp:
816       // | and & in declarations/type expressions represent union and
817       // intersection types, respectively.
818       if (Style.Language == FormatStyle::LK_JavaScript &&
819           !Contexts.back().IsExpression)
820         Tok->Type = TT_JsTypeOperator;
821       break;
822     case tok::kw_if:
823     case tok::kw_while:
824       if (Tok->is(tok::kw_if) && CurrentToken &&
825           CurrentToken->is(tok::kw_constexpr))
826         next();
827       if (CurrentToken && CurrentToken->is(tok::l_paren)) {
828         next();
829         if (!parseParens(/*LookForDecls=*/true))
830           return false;
831       }
832       break;
833     case tok::kw_for:
834       if (Style.Language == FormatStyle::LK_JavaScript) {
835         // x.for and {for: ...}
836         if ((Tok->Previous && Tok->Previous->is(tok::period)) ||
837             (Tok->Next && Tok->Next->is(tok::colon)))
838           break;
839         // JS' for await ( ...
840         if (CurrentToken && CurrentToken->is(Keywords.kw_await))
841           next();
842       }
843       Contexts.back().ColonIsForRangeExpr = true;
844       next();
845       if (!parseParens())
846         return false;
847       break;
848     case tok::l_paren:
849       // When faced with 'operator()()', the kw_operator handler incorrectly
850       // marks the first l_paren as a OverloadedOperatorLParen. Here, we make
851       // the first two parens OverloadedOperators and the second l_paren an
852       // OverloadedOperatorLParen.
853       if (Tok->Previous && Tok->Previous->is(tok::r_paren) &&
854           Tok->Previous->MatchingParen &&
855           Tok->Previous->MatchingParen->is(TT_OverloadedOperatorLParen)) {
856         Tok->Previous->Type = TT_OverloadedOperator;
857         Tok->Previous->MatchingParen->Type = TT_OverloadedOperator;
858         Tok->Type = TT_OverloadedOperatorLParen;
859       }
860 
861       if (!parseParens())
862         return false;
863       if (Line.MustBeDeclaration && Contexts.size() == 1 &&
864           !Contexts.back().IsExpression && !Line.startsWith(TT_ObjCProperty) &&
865           (!Tok->Previous ||
866            !Tok->Previous->isOneOf(tok::kw_decltype, tok::kw___attribute,
867                                    TT_LeadingJavaAnnotation)))
868         Line.MightBeFunctionDecl = true;
869       break;
870     case tok::l_square:
871       if (!parseSquare())
872         return false;
873       break;
874     case tok::l_brace:
875       if (Style.Language == FormatStyle::LK_TextProto) {
876         FormatToken *Previous = Tok->getPreviousNonComment();
877         if (Previous && Previous->Type != TT_DictLiteral)
878           Previous->Type = TT_SelectorName;
879       }
880       if (!parseBrace())
881         return false;
882       break;
883     case tok::less:
884       if (parseAngle()) {
885         Tok->Type = TT_TemplateOpener;
886         // In TT_Proto, we must distignuish between:
887         //   map<key, value>
888         //   msg < item: data >
889         //   msg: < item: data >
890         // In TT_TextProto, map<key, value> does not occur.
891         if (Style.Language == FormatStyle::LK_TextProto ||
892             (Style.Language == FormatStyle::LK_Proto && Tok->Previous &&
893              Tok->Previous->isOneOf(TT_SelectorName, TT_DictLiteral))) {
894           Tok->Type = TT_DictLiteral;
895           FormatToken *Previous = Tok->getPreviousNonComment();
896           if (Previous && Previous->Type != TT_DictLiteral)
897             Previous->Type = TT_SelectorName;
898         }
899       } else {
900         Tok->Type = TT_BinaryOperator;
901         NonTemplateLess.insert(Tok);
902         CurrentToken = Tok;
903         next();
904       }
905       break;
906     case tok::r_paren:
907     case tok::r_square:
908       return false;
909     case tok::r_brace:
910       // Lines can start with '}'.
911       if (Tok->Previous)
912         return false;
913       break;
914     case tok::greater:
915       if (Style.Language != FormatStyle::LK_TextProto)
916         Tok->Type = TT_BinaryOperator;
917       break;
918     case tok::kw_operator:
919       if (Style.Language == FormatStyle::LK_TextProto ||
920           Style.Language == FormatStyle::LK_Proto)
921         break;
922       while (CurrentToken &&
923              !CurrentToken->isOneOf(tok::l_paren, tok::semi, tok::r_paren)) {
924         if (CurrentToken->isOneOf(tok::star, tok::amp))
925           CurrentToken->Type = TT_PointerOrReference;
926         consumeToken();
927         if (CurrentToken &&
928             CurrentToken->Previous->isOneOf(TT_BinaryOperator, TT_UnaryOperator,
929                                             tok::comma))
930           CurrentToken->Previous->Type = TT_OverloadedOperator;
931       }
932       if (CurrentToken) {
933         CurrentToken->Type = TT_OverloadedOperatorLParen;
934         if (CurrentToken->Previous->is(TT_BinaryOperator))
935           CurrentToken->Previous->Type = TT_OverloadedOperator;
936       }
937       break;
938     case tok::question:
939       if (Style.Language == FormatStyle::LK_JavaScript && Tok->Next &&
940           Tok->Next->isOneOf(tok::semi, tok::comma, tok::colon, tok::r_paren,
941                              tok::r_brace)) {
942         // Question marks before semicolons, colons, etc. indicate optional
943         // types (fields, parameters), e.g.
944         //   function(x?: string, y?) {...}
945         //   class X { y?; }
946         Tok->Type = TT_JsTypeOptionalQuestion;
947         break;
948       }
949       // Declarations cannot be conditional expressions, this can only be part
950       // of a type declaration.
951       if (Line.MustBeDeclaration && !Contexts.back().IsExpression &&
952           Style.Language == FormatStyle::LK_JavaScript)
953         break;
954       parseConditional();
955       break;
956     case tok::kw_template:
957       parseTemplateDeclaration();
958       break;
959     case tok::comma:
960       if (Contexts.back().InCtorInitializer)
961         Tok->Type = TT_CtorInitializerComma;
962       else if (Contexts.back().InInheritanceList)
963         Tok->Type = TT_InheritanceComma;
964       else if (Contexts.back().FirstStartOfName &&
965                (Contexts.size() == 1 || Line.startsWith(tok::kw_for))) {
966         Contexts.back().FirstStartOfName->PartOfMultiVariableDeclStmt = true;
967         Line.IsMultiVariableDeclStmt = true;
968       }
969       if (Contexts.back().IsForEachMacro)
970         Contexts.back().IsExpression = true;
971       break;
972     case tok::identifier:
973       if (Tok->isOneOf(Keywords.kw___has_include,
974                        Keywords.kw___has_include_next)) {
975         parseHasInclude();
976       }
977       break;
978     default:
979       break;
980     }
981     return true;
982   }
983 
984   void parseIncludeDirective() {
985     if (CurrentToken && CurrentToken->is(tok::less)) {
986       next();
987       while (CurrentToken) {
988         // Mark tokens up to the trailing line comments as implicit string
989         // literals.
990         if (CurrentToken->isNot(tok::comment) &&
991             !CurrentToken->TokenText.startswith("//"))
992           CurrentToken->Type = TT_ImplicitStringLiteral;
993         next();
994       }
995     }
996   }
997 
998   void parseWarningOrError() {
999     next();
1000     // We still want to format the whitespace left of the first token of the
1001     // warning or error.
1002     next();
1003     while (CurrentToken) {
1004       CurrentToken->Type = TT_ImplicitStringLiteral;
1005       next();
1006     }
1007   }
1008 
1009   void parsePragma() {
1010     next(); // Consume "pragma".
1011     if (CurrentToken &&
1012         CurrentToken->isOneOf(Keywords.kw_mark, Keywords.kw_option)) {
1013       bool IsMark = CurrentToken->is(Keywords.kw_mark);
1014       next(); // Consume "mark".
1015       next(); // Consume first token (so we fix leading whitespace).
1016       while (CurrentToken) {
1017         if (IsMark || CurrentToken->Previous->is(TT_BinaryOperator))
1018           CurrentToken->Type = TT_ImplicitStringLiteral;
1019         next();
1020       }
1021     }
1022   }
1023 
1024   void parseHasInclude() {
1025     if (!CurrentToken || !CurrentToken->is(tok::l_paren))
1026       return;
1027     next(); // '('
1028     parseIncludeDirective();
1029     next(); // ')'
1030   }
1031 
1032   LineType parsePreprocessorDirective() {
1033     bool IsFirstToken = CurrentToken->IsFirst;
1034     LineType Type = LT_PreprocessorDirective;
1035     next();
1036     if (!CurrentToken)
1037       return Type;
1038 
1039     if (Style.Language == FormatStyle::LK_JavaScript && IsFirstToken) {
1040       // JavaScript files can contain shebang lines of the form:
1041       // #!/usr/bin/env node
1042       // Treat these like C++ #include directives.
1043       while (CurrentToken) {
1044         // Tokens cannot be comments here.
1045         CurrentToken->Type = TT_ImplicitStringLiteral;
1046         next();
1047       }
1048       return LT_ImportStatement;
1049     }
1050 
1051     if (CurrentToken->Tok.is(tok::numeric_constant)) {
1052       CurrentToken->SpacesRequiredBefore = 1;
1053       return Type;
1054     }
1055     // Hashes in the middle of a line can lead to any strange token
1056     // sequence.
1057     if (!CurrentToken->Tok.getIdentifierInfo())
1058       return Type;
1059     switch (CurrentToken->Tok.getIdentifierInfo()->getPPKeywordID()) {
1060     case tok::pp_include:
1061     case tok::pp_include_next:
1062     case tok::pp_import:
1063       next();
1064       parseIncludeDirective();
1065       Type = LT_ImportStatement;
1066       break;
1067     case tok::pp_error:
1068     case tok::pp_warning:
1069       parseWarningOrError();
1070       break;
1071     case tok::pp_pragma:
1072       parsePragma();
1073       break;
1074     case tok::pp_if:
1075     case tok::pp_elif:
1076       Contexts.back().IsExpression = true;
1077       parseLine();
1078       break;
1079     default:
1080       break;
1081     }
1082     while (CurrentToken) {
1083       FormatToken *Tok = CurrentToken;
1084       next();
1085       if (Tok->is(tok::l_paren))
1086         parseParens();
1087       else if (Tok->isOneOf(Keywords.kw___has_include,
1088                             Keywords.kw___has_include_next))
1089         parseHasInclude();
1090     }
1091     return Type;
1092   }
1093 
1094 public:
1095   LineType parseLine() {
1096     NonTemplateLess.clear();
1097     if (CurrentToken->is(tok::hash))
1098       return parsePreprocessorDirective();
1099 
1100     // Directly allow to 'import <string-literal>' to support protocol buffer
1101     // definitions (github.com/google/protobuf) or missing "#" (either way we
1102     // should not break the line).
1103     IdentifierInfo *Info = CurrentToken->Tok.getIdentifierInfo();
1104     if ((Style.Language == FormatStyle::LK_Java &&
1105          CurrentToken->is(Keywords.kw_package)) ||
1106         (Info && Info->getPPKeywordID() == tok::pp_import &&
1107          CurrentToken->Next &&
1108          CurrentToken->Next->isOneOf(tok::string_literal, tok::identifier,
1109                                      tok::kw_static))) {
1110       next();
1111       parseIncludeDirective();
1112       return LT_ImportStatement;
1113     }
1114 
1115     // If this line starts and ends in '<' and '>', respectively, it is likely
1116     // part of "#define <a/b.h>".
1117     if (CurrentToken->is(tok::less) && Line.Last->is(tok::greater)) {
1118       parseIncludeDirective();
1119       return LT_ImportStatement;
1120     }
1121 
1122     // In .proto files, top-level options and package statements are very
1123     // similar to import statements and should not be line-wrapped.
1124     if (Style.Language == FormatStyle::LK_Proto && Line.Level == 0 &&
1125         CurrentToken->isOneOf(Keywords.kw_option, Keywords.kw_package)) {
1126       next();
1127       if (CurrentToken && CurrentToken->is(tok::identifier))
1128         return LT_ImportStatement;
1129     }
1130 
1131     bool KeywordVirtualFound = false;
1132     bool ImportStatement = false;
1133 
1134     // import {...} from '...';
1135     if (Style.Language == FormatStyle::LK_JavaScript &&
1136         CurrentToken->is(Keywords.kw_import))
1137       ImportStatement = true;
1138 
1139     while (CurrentToken) {
1140       if (CurrentToken->is(tok::kw_virtual))
1141         KeywordVirtualFound = true;
1142       if (Style.Language == FormatStyle::LK_JavaScript) {
1143         // export {...} from '...';
1144         // An export followed by "from 'some string';" is a re-export from
1145         // another module identified by a URI and is treated as a
1146         // LT_ImportStatement (i.e. prevent wraps on it for long URIs).
1147         // Just "export {...};" or "export class ..." should not be treated as
1148         // an import in this sense.
1149         if (Line.First->is(tok::kw_export) &&
1150             CurrentToken->is(Keywords.kw_from) && CurrentToken->Next &&
1151             CurrentToken->Next->isStringLiteral())
1152           ImportStatement = true;
1153         if (isClosureImportStatement(*CurrentToken))
1154           ImportStatement = true;
1155       }
1156       if (!consumeToken())
1157         return LT_Invalid;
1158     }
1159     if (KeywordVirtualFound)
1160       return LT_VirtualFunctionDecl;
1161     if (ImportStatement)
1162       return LT_ImportStatement;
1163 
1164     if (Line.startsWith(TT_ObjCMethodSpecifier)) {
1165       if (Contexts.back().FirstObjCSelectorName)
1166         Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
1167             Contexts.back().LongestObjCSelectorName;
1168       return LT_ObjCMethodDecl;
1169     }
1170 
1171     return LT_Other;
1172   }
1173 
1174 private:
1175   bool isClosureImportStatement(const FormatToken &Tok) {
1176     // FIXME: Closure-library specific stuff should not be hard-coded but be
1177     // configurable.
1178     return Tok.TokenText == "goog" && Tok.Next && Tok.Next->is(tok::period) &&
1179            Tok.Next->Next &&
1180            (Tok.Next->Next->TokenText == "module" ||
1181             Tok.Next->Next->TokenText == "provide" ||
1182             Tok.Next->Next->TokenText == "require" ||
1183             Tok.Next->Next->TokenText == "requireType" ||
1184             Tok.Next->Next->TokenText == "forwardDeclare") &&
1185            Tok.Next->Next->Next && Tok.Next->Next->Next->is(tok::l_paren);
1186   }
1187 
1188   void resetTokenMetadata(FormatToken *Token) {
1189     if (!Token)
1190       return;
1191 
1192     // Reset token type in case we have already looked at it and then
1193     // recovered from an error (e.g. failure to find the matching >).
1194     if (!CurrentToken->isOneOf(TT_LambdaLSquare, TT_ForEachMacro,
1195                                TT_FunctionLBrace, TT_ImplicitStringLiteral,
1196                                TT_InlineASMBrace, TT_JsFatArrow, TT_LambdaArrow,
1197                                TT_OverloadedOperator, TT_RegexLiteral,
1198                                TT_TemplateString, TT_ObjCStringLiteral))
1199       CurrentToken->Type = TT_Unknown;
1200     CurrentToken->Role.reset();
1201     CurrentToken->MatchingParen = nullptr;
1202     CurrentToken->FakeLParens.clear();
1203     CurrentToken->FakeRParens = 0;
1204   }
1205 
1206   void next() {
1207     if (CurrentToken) {
1208       CurrentToken->NestingLevel = Contexts.size() - 1;
1209       CurrentToken->BindingStrength = Contexts.back().BindingStrength;
1210       modifyContext(*CurrentToken);
1211       determineTokenType(*CurrentToken);
1212       CurrentToken = CurrentToken->Next;
1213     }
1214 
1215     resetTokenMetadata(CurrentToken);
1216   }
1217 
1218   /// A struct to hold information valid in a specific context, e.g.
1219   /// a pair of parenthesis.
1220   struct Context {
1221     Context(tok::TokenKind ContextKind, unsigned BindingStrength,
1222             bool IsExpression)
1223         : ContextKind(ContextKind), BindingStrength(BindingStrength),
1224           IsExpression(IsExpression) {}
1225 
1226     tok::TokenKind ContextKind;
1227     unsigned BindingStrength;
1228     bool IsExpression;
1229     unsigned LongestObjCSelectorName = 0;
1230     bool ColonIsForRangeExpr = false;
1231     bool ColonIsDictLiteral = false;
1232     bool ColonIsObjCMethodExpr = false;
1233     FormatToken *FirstObjCSelectorName = nullptr;
1234     FormatToken *FirstStartOfName = nullptr;
1235     bool CanBeExpression = true;
1236     bool InTemplateArgument = false;
1237     bool InCtorInitializer = false;
1238     bool InInheritanceList = false;
1239     bool CaretFound = false;
1240     bool IsForEachMacro = false;
1241     bool InCpp11AttributeSpecifier = false;
1242     bool InCSharpAttributeSpecifier = false;
1243   };
1244 
1245   /// Puts a new \c Context onto the stack \c Contexts for the lifetime
1246   /// of each instance.
1247   struct ScopedContextCreator {
1248     AnnotatingParser &P;
1249 
1250     ScopedContextCreator(AnnotatingParser &P, tok::TokenKind ContextKind,
1251                          unsigned Increase)
1252         : P(P) {
1253       P.Contexts.push_back(Context(ContextKind,
1254                                    P.Contexts.back().BindingStrength + Increase,
1255                                    P.Contexts.back().IsExpression));
1256     }
1257 
1258     ~ScopedContextCreator() { P.Contexts.pop_back(); }
1259   };
1260 
1261   void modifyContext(const FormatToken &Current) {
1262     if (Current.getPrecedence() == prec::Assignment &&
1263         !Line.First->isOneOf(tok::kw_template, tok::kw_using, tok::kw_return) &&
1264         // Type aliases use `type X = ...;` in TypeScript and can be exported
1265         // using `export type ...`.
1266         !(Style.Language == FormatStyle::LK_JavaScript &&
1267           (Line.startsWith(Keywords.kw_type, tok::identifier) ||
1268            Line.startsWith(tok::kw_export, Keywords.kw_type,
1269                            tok::identifier))) &&
1270         (!Current.Previous || Current.Previous->isNot(tok::kw_operator))) {
1271       Contexts.back().IsExpression = true;
1272       if (!Line.startsWith(TT_UnaryOperator)) {
1273         for (FormatToken *Previous = Current.Previous;
1274              Previous && Previous->Previous &&
1275              !Previous->Previous->isOneOf(tok::comma, tok::semi);
1276              Previous = Previous->Previous) {
1277           if (Previous->isOneOf(tok::r_square, tok::r_paren)) {
1278             Previous = Previous->MatchingParen;
1279             if (!Previous)
1280               break;
1281           }
1282           if (Previous->opensScope())
1283             break;
1284           if (Previous->isOneOf(TT_BinaryOperator, TT_UnaryOperator) &&
1285               Previous->isOneOf(tok::star, tok::amp, tok::ampamp) &&
1286               Previous->Previous && Previous->Previous->isNot(tok::equal))
1287             Previous->Type = TT_PointerOrReference;
1288         }
1289       }
1290     } else if (Current.is(tok::lessless) &&
1291                (!Current.Previous || !Current.Previous->is(tok::kw_operator))) {
1292       Contexts.back().IsExpression = true;
1293     } else if (Current.isOneOf(tok::kw_return, tok::kw_throw)) {
1294       Contexts.back().IsExpression = true;
1295     } else if (Current.is(TT_TrailingReturnArrow)) {
1296       Contexts.back().IsExpression = false;
1297     } else if (Current.is(TT_LambdaArrow) || Current.is(Keywords.kw_assert)) {
1298       Contexts.back().IsExpression = Style.Language == FormatStyle::LK_Java;
1299     } else if (Current.Previous &&
1300                Current.Previous->is(TT_CtorInitializerColon)) {
1301       Contexts.back().IsExpression = true;
1302       Contexts.back().InCtorInitializer = true;
1303     } else if (Current.Previous && Current.Previous->is(TT_InheritanceColon)) {
1304       Contexts.back().InInheritanceList = true;
1305     } else if (Current.isOneOf(tok::r_paren, tok::greater, tok::comma)) {
1306       for (FormatToken *Previous = Current.Previous;
1307            Previous && Previous->isOneOf(tok::star, tok::amp);
1308            Previous = Previous->Previous)
1309         Previous->Type = TT_PointerOrReference;
1310       if (Line.MustBeDeclaration && !Contexts.front().InCtorInitializer)
1311         Contexts.back().IsExpression = false;
1312     } else if (Current.is(tok::kw_new)) {
1313       Contexts.back().CanBeExpression = false;
1314     } else if (Current.isOneOf(tok::semi, tok::exclaim)) {
1315       // This should be the condition or increment in a for-loop.
1316       Contexts.back().IsExpression = true;
1317     }
1318   }
1319 
1320   void determineTokenType(FormatToken &Current) {
1321     if (!Current.is(TT_Unknown))
1322       // The token type is already known.
1323       return;
1324 
1325     if (Style.Language == FormatStyle::LK_JavaScript) {
1326       if (Current.is(tok::exclaim)) {
1327         if (Current.Previous &&
1328             (Current.Previous->isOneOf(tok::identifier, tok::kw_namespace,
1329                                        tok::r_paren, tok::r_square,
1330                                        tok::r_brace) ||
1331              Current.Previous->Tok.isLiteral())) {
1332           Current.Type = TT_JsNonNullAssertion;
1333           return;
1334         }
1335         if (Current.Next &&
1336             Current.Next->isOneOf(TT_BinaryOperator, Keywords.kw_as)) {
1337           Current.Type = TT_JsNonNullAssertion;
1338           return;
1339         }
1340       }
1341     }
1342 
1343     // Line.MightBeFunctionDecl can only be true after the parentheses of a
1344     // function declaration have been found. In this case, 'Current' is a
1345     // trailing token of this declaration and thus cannot be a name.
1346     if (Current.is(Keywords.kw_instanceof)) {
1347       Current.Type = TT_BinaryOperator;
1348     } else if (isStartOfName(Current) &&
1349                (!Line.MightBeFunctionDecl || Current.NestingLevel != 0)) {
1350       Contexts.back().FirstStartOfName = &Current;
1351       Current.Type = TT_StartOfName;
1352     } else if (Current.is(tok::semi)) {
1353       // Reset FirstStartOfName after finding a semicolon so that a for loop
1354       // with multiple increment statements is not confused with a for loop
1355       // having multiple variable declarations.
1356       Contexts.back().FirstStartOfName = nullptr;
1357     } else if (Current.isOneOf(tok::kw_auto, tok::kw___auto_type)) {
1358       AutoFound = true;
1359     } else if (Current.is(tok::arrow) &&
1360                Style.Language == FormatStyle::LK_Java) {
1361       Current.Type = TT_LambdaArrow;
1362     } else if (Current.is(tok::arrow) && AutoFound && Line.MustBeDeclaration &&
1363                Current.NestingLevel == 0) {
1364       Current.Type = TT_TrailingReturnArrow;
1365     } else if (Current.isOneOf(tok::star, tok::amp, tok::ampamp)) {
1366       Current.Type = determineStarAmpUsage(Current,
1367                                            Contexts.back().CanBeExpression &&
1368                                                Contexts.back().IsExpression,
1369                                            Contexts.back().InTemplateArgument);
1370     } else if (Current.isOneOf(tok::minus, tok::plus, tok::caret)) {
1371       Current.Type = determinePlusMinusCaretUsage(Current);
1372       if (Current.is(TT_UnaryOperator) && Current.is(tok::caret))
1373         Contexts.back().CaretFound = true;
1374     } else if (Current.isOneOf(tok::minusminus, tok::plusplus)) {
1375       Current.Type = determineIncrementUsage(Current);
1376     } else if (Current.isOneOf(tok::exclaim, tok::tilde)) {
1377       Current.Type = TT_UnaryOperator;
1378     } else if (Current.is(tok::question)) {
1379       if (Style.Language == FormatStyle::LK_JavaScript &&
1380           Line.MustBeDeclaration && !Contexts.back().IsExpression) {
1381         // In JavaScript, `interface X { foo?(): bar; }` is an optional method
1382         // on the interface, not a ternary expression.
1383         Current.Type = TT_JsTypeOptionalQuestion;
1384       } else {
1385         Current.Type = TT_ConditionalExpr;
1386       }
1387     } else if (Current.isBinaryOperator() &&
1388                (!Current.Previous || Current.Previous->isNot(tok::l_square)) &&
1389                (!Current.is(tok::greater) &&
1390                 Style.Language != FormatStyle::LK_TextProto)) {
1391       Current.Type = TT_BinaryOperator;
1392     } else if (Current.is(tok::comment)) {
1393       if (Current.TokenText.startswith("/*")) {
1394         if (Current.TokenText.endswith("*/"))
1395           Current.Type = TT_BlockComment;
1396         else
1397           // The lexer has for some reason determined a comment here. But we
1398           // cannot really handle it, if it isn't properly terminated.
1399           Current.Tok.setKind(tok::unknown);
1400       } else {
1401         Current.Type = TT_LineComment;
1402       }
1403     } else if (Current.is(tok::r_paren)) {
1404       if (rParenEndsCast(Current))
1405         Current.Type = TT_CastRParen;
1406       if (Current.MatchingParen && Current.Next &&
1407           !Current.Next->isBinaryOperator() &&
1408           !Current.Next->isOneOf(tok::semi, tok::colon, tok::l_brace,
1409                                  tok::comma, tok::period, tok::arrow,
1410                                  tok::coloncolon))
1411         if (FormatToken *AfterParen = Current.MatchingParen->Next) {
1412           // Make sure this isn't the return type of an Obj-C block declaration
1413           if (AfterParen->Tok.isNot(tok::caret)) {
1414             if (FormatToken *BeforeParen = Current.MatchingParen->Previous)
1415               if (BeforeParen->is(tok::identifier) &&
1416                   BeforeParen->TokenText == BeforeParen->TokenText.upper() &&
1417                   (!BeforeParen->Previous ||
1418                    BeforeParen->Previous->ClosesTemplateDeclaration))
1419                 Current.Type = TT_FunctionAnnotationRParen;
1420           }
1421         }
1422     } else if (Current.is(tok::at) && Current.Next &&
1423                Style.Language != FormatStyle::LK_JavaScript &&
1424                Style.Language != FormatStyle::LK_Java) {
1425       // In Java & JavaScript, "@..." is a decorator or annotation. In ObjC, it
1426       // marks declarations and properties that need special formatting.
1427       switch (Current.Next->Tok.getObjCKeywordID()) {
1428       case tok::objc_interface:
1429       case tok::objc_implementation:
1430       case tok::objc_protocol:
1431         Current.Type = TT_ObjCDecl;
1432         break;
1433       case tok::objc_property:
1434         Current.Type = TT_ObjCProperty;
1435         break;
1436       default:
1437         break;
1438       }
1439     } else if (Current.is(tok::period)) {
1440       FormatToken *PreviousNoComment = Current.getPreviousNonComment();
1441       if (PreviousNoComment &&
1442           PreviousNoComment->isOneOf(tok::comma, tok::l_brace))
1443         Current.Type = TT_DesignatedInitializerPeriod;
1444       else if (Style.Language == FormatStyle::LK_Java && Current.Previous &&
1445                Current.Previous->isOneOf(TT_JavaAnnotation,
1446                                          TT_LeadingJavaAnnotation)) {
1447         Current.Type = Current.Previous->Type;
1448       }
1449     } else if (canBeObjCSelectorComponent(Current) &&
1450                // FIXME(bug 36976): ObjC return types shouldn't use
1451                // TT_CastRParen.
1452                Current.Previous && Current.Previous->is(TT_CastRParen) &&
1453                Current.Previous->MatchingParen &&
1454                Current.Previous->MatchingParen->Previous &&
1455                Current.Previous->MatchingParen->Previous->is(
1456                    TT_ObjCMethodSpecifier)) {
1457       // This is the first part of an Objective-C selector name. (If there's no
1458       // colon after this, this is the only place which annotates the identifier
1459       // as a selector.)
1460       Current.Type = TT_SelectorName;
1461     } else if (Current.isOneOf(tok::identifier, tok::kw_const) &&
1462                Current.Previous &&
1463                !Current.Previous->isOneOf(tok::equal, tok::at) &&
1464                Line.MightBeFunctionDecl && Contexts.size() == 1) {
1465       // Line.MightBeFunctionDecl can only be true after the parentheses of a
1466       // function declaration have been found.
1467       Current.Type = TT_TrailingAnnotation;
1468     } else if ((Style.Language == FormatStyle::LK_Java ||
1469                 Style.Language == FormatStyle::LK_JavaScript) &&
1470                Current.Previous) {
1471       if (Current.Previous->is(tok::at) &&
1472           Current.isNot(Keywords.kw_interface)) {
1473         const FormatToken &AtToken = *Current.Previous;
1474         const FormatToken *Previous = AtToken.getPreviousNonComment();
1475         if (!Previous || Previous->is(TT_LeadingJavaAnnotation))
1476           Current.Type = TT_LeadingJavaAnnotation;
1477         else
1478           Current.Type = TT_JavaAnnotation;
1479       } else if (Current.Previous->is(tok::period) &&
1480                  Current.Previous->isOneOf(TT_JavaAnnotation,
1481                                            TT_LeadingJavaAnnotation)) {
1482         Current.Type = Current.Previous->Type;
1483       }
1484     }
1485   }
1486 
1487   /// Take a guess at whether \p Tok starts a name of a function or
1488   /// variable declaration.
1489   ///
1490   /// This is a heuristic based on whether \p Tok is an identifier following
1491   /// something that is likely a type.
1492   bool isStartOfName(const FormatToken &Tok) {
1493     if (Tok.isNot(tok::identifier) || !Tok.Previous)
1494       return false;
1495 
1496     if (Tok.Previous->isOneOf(TT_LeadingJavaAnnotation, Keywords.kw_instanceof,
1497                               Keywords.kw_as))
1498       return false;
1499     if (Style.Language == FormatStyle::LK_JavaScript &&
1500         Tok.Previous->is(Keywords.kw_in))
1501       return false;
1502 
1503     // Skip "const" as it does not have an influence on whether this is a name.
1504     FormatToken *PreviousNotConst = Tok.getPreviousNonComment();
1505     while (PreviousNotConst && PreviousNotConst->is(tok::kw_const))
1506       PreviousNotConst = PreviousNotConst->getPreviousNonComment();
1507 
1508     if (!PreviousNotConst)
1509       return false;
1510 
1511     bool IsPPKeyword = PreviousNotConst->is(tok::identifier) &&
1512                        PreviousNotConst->Previous &&
1513                        PreviousNotConst->Previous->is(tok::hash);
1514 
1515     if (PreviousNotConst->is(TT_TemplateCloser))
1516       return PreviousNotConst && PreviousNotConst->MatchingParen &&
1517              PreviousNotConst->MatchingParen->Previous &&
1518              PreviousNotConst->MatchingParen->Previous->isNot(tok::period) &&
1519              PreviousNotConst->MatchingParen->Previous->isNot(tok::kw_template);
1520 
1521     if (PreviousNotConst->is(tok::r_paren) && PreviousNotConst->MatchingParen &&
1522         PreviousNotConst->MatchingParen->Previous &&
1523         PreviousNotConst->MatchingParen->Previous->is(tok::kw_decltype))
1524       return true;
1525 
1526     return (!IsPPKeyword &&
1527             PreviousNotConst->isOneOf(tok::identifier, tok::kw_auto)) ||
1528            PreviousNotConst->is(TT_PointerOrReference) ||
1529            PreviousNotConst->isSimpleTypeSpecifier();
1530   }
1531 
1532   /// Determine whether ')' is ending a cast.
1533   bool rParenEndsCast(const FormatToken &Tok) {
1534     // C-style casts are only used in C++ and Java.
1535     if (!Style.isCpp() && Style.Language != FormatStyle::LK_Java)
1536       return false;
1537 
1538     // Empty parens aren't casts and there are no casts at the end of the line.
1539     if (Tok.Previous == Tok.MatchingParen || !Tok.Next || !Tok.MatchingParen)
1540       return false;
1541 
1542     FormatToken *LeftOfParens = Tok.MatchingParen->getPreviousNonComment();
1543     if (LeftOfParens) {
1544       // If there is a closing parenthesis left of the current parentheses,
1545       // look past it as these might be chained casts.
1546       if (LeftOfParens->is(tok::r_paren)) {
1547         if (!LeftOfParens->MatchingParen ||
1548             !LeftOfParens->MatchingParen->Previous)
1549           return false;
1550         LeftOfParens = LeftOfParens->MatchingParen->Previous;
1551       }
1552 
1553       // If there is an identifier (or with a few exceptions a keyword) right
1554       // before the parentheses, this is unlikely to be a cast.
1555       if (LeftOfParens->Tok.getIdentifierInfo() &&
1556           !LeftOfParens->isOneOf(Keywords.kw_in, tok::kw_return, tok::kw_case,
1557                                  tok::kw_delete))
1558         return false;
1559 
1560       // Certain other tokens right before the parentheses are also signals that
1561       // this cannot be a cast.
1562       if (LeftOfParens->isOneOf(tok::at, tok::r_square, TT_OverloadedOperator,
1563                                 TT_TemplateCloser, tok::ellipsis))
1564         return false;
1565     }
1566 
1567     if (Tok.Next->is(tok::question))
1568       return false;
1569 
1570     // As Java has no function types, a "(" after the ")" likely means that this
1571     // is a cast.
1572     if (Style.Language == FormatStyle::LK_Java && Tok.Next->is(tok::l_paren))
1573       return true;
1574 
1575     // If a (non-string) literal follows, this is likely a cast.
1576     if (Tok.Next->isNot(tok::string_literal) &&
1577         (Tok.Next->Tok.isLiteral() ||
1578          Tok.Next->isOneOf(tok::kw_sizeof, tok::kw_alignof)))
1579       return true;
1580 
1581     // Heuristically try to determine whether the parentheses contain a type.
1582     bool ParensAreType =
1583         !Tok.Previous ||
1584         Tok.Previous->isOneOf(TT_PointerOrReference, TT_TemplateCloser) ||
1585         Tok.Previous->isSimpleTypeSpecifier();
1586     bool ParensCouldEndDecl =
1587         Tok.Next->isOneOf(tok::equal, tok::semi, tok::l_brace, tok::greater);
1588     if (ParensAreType && !ParensCouldEndDecl)
1589       return true;
1590 
1591     // At this point, we heuristically assume that there are no casts at the
1592     // start of the line. We assume that we have found most cases where there
1593     // are by the logic above, e.g. "(void)x;".
1594     if (!LeftOfParens)
1595       return false;
1596 
1597     // Certain token types inside the parentheses mean that this can't be a
1598     // cast.
1599     for (const FormatToken *Token = Tok.MatchingParen->Next; Token != &Tok;
1600          Token = Token->Next)
1601       if (Token->is(TT_BinaryOperator))
1602         return false;
1603 
1604     // If the following token is an identifier or 'this', this is a cast. All
1605     // cases where this can be something else are handled above.
1606     if (Tok.Next->isOneOf(tok::identifier, tok::kw_this))
1607       return true;
1608 
1609     if (!Tok.Next->Next)
1610       return false;
1611 
1612     // If the next token after the parenthesis is a unary operator, assume
1613     // that this is cast, unless there are unexpected tokens inside the
1614     // parenthesis.
1615     bool NextIsUnary =
1616         Tok.Next->isUnaryOperator() || Tok.Next->isOneOf(tok::amp, tok::star);
1617     if (!NextIsUnary || Tok.Next->is(tok::plus) ||
1618         !Tok.Next->Next->isOneOf(tok::identifier, tok::numeric_constant))
1619       return false;
1620     // Search for unexpected tokens.
1621     for (FormatToken *Prev = Tok.Previous; Prev != Tok.MatchingParen;
1622          Prev = Prev->Previous) {
1623       if (!Prev->isOneOf(tok::kw_const, tok::identifier, tok::coloncolon))
1624         return false;
1625     }
1626     return true;
1627   }
1628 
1629   /// Return the type of the given token assuming it is * or &.
1630   TokenType determineStarAmpUsage(const FormatToken &Tok, bool IsExpression,
1631                                   bool InTemplateArgument) {
1632     if (Style.Language == FormatStyle::LK_JavaScript)
1633       return TT_BinaryOperator;
1634 
1635     const FormatToken *PrevToken = Tok.getPreviousNonComment();
1636     if (!PrevToken)
1637       return TT_UnaryOperator;
1638 
1639     const FormatToken *NextToken = Tok.getNextNonComment();
1640     if (!NextToken ||
1641         NextToken->isOneOf(tok::arrow, tok::equal, tok::kw_const) ||
1642         (NextToken->is(tok::l_brace) && !NextToken->getNextNonComment()))
1643       return TT_PointerOrReference;
1644 
1645     if (PrevToken->is(tok::coloncolon))
1646       return TT_PointerOrReference;
1647 
1648     if (PrevToken->isOneOf(tok::l_paren, tok::l_square, tok::l_brace,
1649                            tok::comma, tok::semi, tok::kw_return, tok::colon,
1650                            tok::equal, tok::kw_delete, tok::kw_sizeof,
1651                            tok::kw_throw) ||
1652         PrevToken->isOneOf(TT_BinaryOperator, TT_ConditionalExpr,
1653                            TT_UnaryOperator, TT_CastRParen))
1654       return TT_UnaryOperator;
1655 
1656     if (NextToken->is(tok::l_square) && NextToken->isNot(TT_LambdaLSquare))
1657       return TT_PointerOrReference;
1658     if (NextToken->is(tok::kw_operator) && !IsExpression)
1659       return TT_PointerOrReference;
1660     if (NextToken->isOneOf(tok::comma, tok::semi))
1661       return TT_PointerOrReference;
1662 
1663     if (PrevToken->is(tok::r_paren) && PrevToken->MatchingParen) {
1664       FormatToken *TokenBeforeMatchingParen =
1665           PrevToken->MatchingParen->getPreviousNonComment();
1666       if (TokenBeforeMatchingParen &&
1667           TokenBeforeMatchingParen->isOneOf(tok::kw_typeof, tok::kw_decltype))
1668         return TT_PointerOrReference;
1669     }
1670 
1671     if (PrevToken->Tok.isLiteral() ||
1672         PrevToken->isOneOf(tok::r_paren, tok::r_square, tok::kw_true,
1673                            tok::kw_false, tok::r_brace) ||
1674         NextToken->Tok.isLiteral() ||
1675         NextToken->isOneOf(tok::kw_true, tok::kw_false) ||
1676         NextToken->isUnaryOperator() ||
1677         // If we know we're in a template argument, there are no named
1678         // declarations. Thus, having an identifier on the right-hand side
1679         // indicates a binary operator.
1680         (InTemplateArgument && NextToken->Tok.isAnyIdentifier()))
1681       return TT_BinaryOperator;
1682 
1683     // "&&(" is quite unlikely to be two successive unary "&".
1684     if (Tok.is(tok::ampamp) && NextToken && NextToken->is(tok::l_paren))
1685       return TT_BinaryOperator;
1686 
1687     // This catches some cases where evaluation order is used as control flow:
1688     //   aaa && aaa->f();
1689     const FormatToken *NextNextToken = NextToken->getNextNonComment();
1690     if (NextNextToken && NextNextToken->is(tok::arrow))
1691       return TT_BinaryOperator;
1692 
1693     // It is very unlikely that we are going to find a pointer or reference type
1694     // definition on the RHS of an assignment.
1695     if (IsExpression && !Contexts.back().CaretFound)
1696       return TT_BinaryOperator;
1697 
1698     return TT_PointerOrReference;
1699   }
1700 
1701   TokenType determinePlusMinusCaretUsage(const FormatToken &Tok) {
1702     const FormatToken *PrevToken = Tok.getPreviousNonComment();
1703     if (!PrevToken)
1704       return TT_UnaryOperator;
1705 
1706     if (PrevToken->isOneOf(TT_CastRParen, TT_UnaryOperator))
1707       // This must be a sequence of leading unary operators.
1708       return TT_UnaryOperator;
1709 
1710     // Use heuristics to recognize unary operators.
1711     if (PrevToken->isOneOf(tok::equal, tok::l_paren, tok::comma, tok::l_square,
1712                            tok::question, tok::colon, tok::kw_return,
1713                            tok::kw_case, tok::at, tok::l_brace))
1714       return TT_UnaryOperator;
1715 
1716     // There can't be two consecutive binary operators.
1717     if (PrevToken->is(TT_BinaryOperator))
1718       return TT_UnaryOperator;
1719 
1720     // Fall back to marking the token as binary operator.
1721     return TT_BinaryOperator;
1722   }
1723 
1724   /// Determine whether ++/-- are pre- or post-increments/-decrements.
1725   TokenType determineIncrementUsage(const FormatToken &Tok) {
1726     const FormatToken *PrevToken = Tok.getPreviousNonComment();
1727     if (!PrevToken || PrevToken->is(TT_CastRParen))
1728       return TT_UnaryOperator;
1729     if (PrevToken->isOneOf(tok::r_paren, tok::r_square, tok::identifier))
1730       return TT_TrailingUnaryOperator;
1731 
1732     return TT_UnaryOperator;
1733   }
1734 
1735   SmallVector<Context, 8> Contexts;
1736 
1737   const FormatStyle &Style;
1738   AnnotatedLine &Line;
1739   FormatToken *CurrentToken;
1740   bool AutoFound;
1741   const AdditionalKeywords &Keywords;
1742 
1743   // Set of "<" tokens that do not open a template parameter list. If parseAngle
1744   // determines that a specific token can't be a template opener, it will make
1745   // same decision irrespective of the decisions for tokens leading up to it.
1746   // Store this information to prevent this from causing exponential runtime.
1747   llvm::SmallPtrSet<FormatToken *, 16> NonTemplateLess;
1748 };
1749 
1750 static const int PrecedenceUnaryOperator = prec::PointerToMember + 1;
1751 static const int PrecedenceArrowAndPeriod = prec::PointerToMember + 2;
1752 
1753 /// Parses binary expressions by inserting fake parenthesis based on
1754 /// operator precedence.
1755 class ExpressionParser {
1756 public:
1757   ExpressionParser(const FormatStyle &Style, const AdditionalKeywords &Keywords,
1758                    AnnotatedLine &Line)
1759       : Style(Style), Keywords(Keywords), Current(Line.First) {}
1760 
1761   /// Parse expressions with the given operator precedence.
1762   void parse(int Precedence = 0) {
1763     // Skip 'return' and ObjC selector colons as they are not part of a binary
1764     // expression.
1765     while (Current && (Current->is(tok::kw_return) ||
1766                        (Current->is(tok::colon) &&
1767                         Current->isOneOf(TT_ObjCMethodExpr, TT_DictLiteral))))
1768       next();
1769 
1770     if (!Current || Precedence > PrecedenceArrowAndPeriod)
1771       return;
1772 
1773     // Conditional expressions need to be parsed separately for proper nesting.
1774     if (Precedence == prec::Conditional) {
1775       parseConditionalExpr();
1776       return;
1777     }
1778 
1779     // Parse unary operators, which all have a higher precedence than binary
1780     // operators.
1781     if (Precedence == PrecedenceUnaryOperator) {
1782       parseUnaryOperator();
1783       return;
1784     }
1785 
1786     FormatToken *Start = Current;
1787     FormatToken *LatestOperator = nullptr;
1788     unsigned OperatorIndex = 0;
1789 
1790     while (Current) {
1791       // Consume operators with higher precedence.
1792       parse(Precedence + 1);
1793 
1794       int CurrentPrecedence = getCurrentPrecedence();
1795 
1796       if (Current && Current->is(TT_SelectorName) &&
1797           Precedence == CurrentPrecedence) {
1798         if (LatestOperator)
1799           addFakeParenthesis(Start, prec::Level(Precedence));
1800         Start = Current;
1801       }
1802 
1803       // At the end of the line or when an operator with higher precedence is
1804       // found, insert fake parenthesis and return.
1805       if (!Current ||
1806           (Current->closesScope() &&
1807            (Current->MatchingParen || Current->is(TT_TemplateString))) ||
1808           (CurrentPrecedence != -1 && CurrentPrecedence < Precedence) ||
1809           (CurrentPrecedence == prec::Conditional &&
1810            Precedence == prec::Assignment && Current->is(tok::colon))) {
1811         break;
1812       }
1813 
1814       // Consume scopes: (), [], <> and {}
1815       if (Current->opensScope()) {
1816         // In fragment of a JavaScript template string can look like '}..${' and
1817         // thus close a scope and open a new one at the same time.
1818         while (Current && (!Current->closesScope() || Current->opensScope())) {
1819           next();
1820           parse();
1821         }
1822         next();
1823       } else {
1824         // Operator found.
1825         if (CurrentPrecedence == Precedence) {
1826           if (LatestOperator)
1827             LatestOperator->NextOperator = Current;
1828           LatestOperator = Current;
1829           Current->OperatorIndex = OperatorIndex;
1830           ++OperatorIndex;
1831         }
1832         next(/*SkipPastLeadingComments=*/Precedence > 0);
1833       }
1834     }
1835 
1836     if (LatestOperator && (Current || Precedence > 0)) {
1837       // LatestOperator->LastOperator = true;
1838       if (Precedence == PrecedenceArrowAndPeriod) {
1839         // Call expressions don't have a binary operator precedence.
1840         addFakeParenthesis(Start, prec::Unknown);
1841       } else {
1842         addFakeParenthesis(Start, prec::Level(Precedence));
1843       }
1844     }
1845   }
1846 
1847 private:
1848   /// Gets the precedence (+1) of the given token for binary operators
1849   /// and other tokens that we treat like binary operators.
1850   int getCurrentPrecedence() {
1851     if (Current) {
1852       const FormatToken *NextNonComment = Current->getNextNonComment();
1853       if (Current->is(TT_ConditionalExpr))
1854         return prec::Conditional;
1855       if (NextNonComment && Current->is(TT_SelectorName) &&
1856           (NextNonComment->isOneOf(TT_DictLiteral, TT_JsTypeColon) ||
1857            ((Style.Language == FormatStyle::LK_Proto ||
1858              Style.Language == FormatStyle::LK_TextProto) &&
1859             NextNonComment->is(tok::less))))
1860         return prec::Assignment;
1861       if (Current->is(TT_JsComputedPropertyName))
1862         return prec::Assignment;
1863       if (Current->is(TT_LambdaArrow))
1864         return prec::Comma;
1865       if (Current->is(TT_JsFatArrow))
1866         return prec::Assignment;
1867       if (Current->isOneOf(tok::semi, TT_InlineASMColon, TT_SelectorName) ||
1868           (Current->is(tok::comment) && NextNonComment &&
1869            NextNonComment->is(TT_SelectorName)))
1870         return 0;
1871       if (Current->is(TT_RangeBasedForLoopColon))
1872         return prec::Comma;
1873       if ((Style.Language == FormatStyle::LK_Java ||
1874            Style.Language == FormatStyle::LK_JavaScript) &&
1875           Current->is(Keywords.kw_instanceof))
1876         return prec::Relational;
1877       if (Style.Language == FormatStyle::LK_JavaScript &&
1878           Current->isOneOf(Keywords.kw_in, Keywords.kw_as))
1879         return prec::Relational;
1880       if (Current->is(TT_BinaryOperator) || Current->is(tok::comma))
1881         return Current->getPrecedence();
1882       if (Current->isOneOf(tok::period, tok::arrow))
1883         return PrecedenceArrowAndPeriod;
1884       if ((Style.Language == FormatStyle::LK_Java ||
1885            Style.Language == FormatStyle::LK_JavaScript) &&
1886           Current->isOneOf(Keywords.kw_extends, Keywords.kw_implements,
1887                            Keywords.kw_throws))
1888         return 0;
1889     }
1890     return -1;
1891   }
1892 
1893   void addFakeParenthesis(FormatToken *Start, prec::Level Precedence) {
1894     Start->FakeLParens.push_back(Precedence);
1895     if (Precedence > prec::Unknown)
1896       Start->StartsBinaryExpression = true;
1897     if (Current) {
1898       FormatToken *Previous = Current->Previous;
1899       while (Previous->is(tok::comment) && Previous->Previous)
1900         Previous = Previous->Previous;
1901       ++Previous->FakeRParens;
1902       if (Precedence > prec::Unknown)
1903         Previous->EndsBinaryExpression = true;
1904     }
1905   }
1906 
1907   /// Parse unary operator expressions and surround them with fake
1908   /// parentheses if appropriate.
1909   void parseUnaryOperator() {
1910     llvm::SmallVector<FormatToken *, 2> Tokens;
1911     while (Current && Current->is(TT_UnaryOperator)) {
1912       Tokens.push_back(Current);
1913       next();
1914     }
1915     parse(PrecedenceArrowAndPeriod);
1916     for (FormatToken *Token : llvm::reverse(Tokens))
1917       // The actual precedence doesn't matter.
1918       addFakeParenthesis(Token, prec::Unknown);
1919   }
1920 
1921   void parseConditionalExpr() {
1922     while (Current && Current->isTrailingComment()) {
1923       next();
1924     }
1925     FormatToken *Start = Current;
1926     parse(prec::LogicalOr);
1927     if (!Current || !Current->is(tok::question))
1928       return;
1929     next();
1930     parse(prec::Assignment);
1931     if (!Current || Current->isNot(TT_ConditionalExpr))
1932       return;
1933     next();
1934     parse(prec::Assignment);
1935     addFakeParenthesis(Start, prec::Conditional);
1936   }
1937 
1938   void next(bool SkipPastLeadingComments = true) {
1939     if (Current)
1940       Current = Current->Next;
1941     while (Current &&
1942            (Current->NewlinesBefore == 0 || SkipPastLeadingComments) &&
1943            Current->isTrailingComment())
1944       Current = Current->Next;
1945   }
1946 
1947   const FormatStyle &Style;
1948   const AdditionalKeywords &Keywords;
1949   FormatToken *Current;
1950 };
1951 
1952 } // end anonymous namespace
1953 
1954 void TokenAnnotator::setCommentLineLevels(
1955     SmallVectorImpl<AnnotatedLine *> &Lines) {
1956   const AnnotatedLine *NextNonCommentLine = nullptr;
1957   for (SmallVectorImpl<AnnotatedLine *>::reverse_iterator I = Lines.rbegin(),
1958                                                           E = Lines.rend();
1959        I != E; ++I) {
1960     bool CommentLine = true;
1961     for (const FormatToken *Tok = (*I)->First; Tok; Tok = Tok->Next) {
1962       if (!Tok->is(tok::comment)) {
1963         CommentLine = false;
1964         break;
1965       }
1966     }
1967 
1968     // If the comment is currently aligned with the line immediately following
1969     // it, that's probably intentional and we should keep it.
1970     if (NextNonCommentLine && CommentLine &&
1971         NextNonCommentLine->First->NewlinesBefore <= 1 &&
1972         NextNonCommentLine->First->OriginalColumn ==
1973             (*I)->First->OriginalColumn) {
1974       // Align comments for preprocessor lines with the # in column 0 if
1975       // preprocessor lines are not indented. Otherwise, align with the next
1976       // line.
1977       (*I)->Level =
1978           (Style.IndentPPDirectives != FormatStyle::PPDIS_BeforeHash &&
1979            (NextNonCommentLine->Type == LT_PreprocessorDirective ||
1980             NextNonCommentLine->Type == LT_ImportStatement))
1981               ? 0
1982               : NextNonCommentLine->Level;
1983     } else {
1984       NextNonCommentLine = (*I)->First->isNot(tok::r_brace) ? (*I) : nullptr;
1985     }
1986 
1987     setCommentLineLevels((*I)->Children);
1988   }
1989 }
1990 
1991 static unsigned maxNestingDepth(const AnnotatedLine &Line) {
1992   unsigned Result = 0;
1993   for (const auto *Tok = Line.First; Tok != nullptr; Tok = Tok->Next)
1994     Result = std::max(Result, Tok->NestingLevel);
1995   return Result;
1996 }
1997 
1998 void TokenAnnotator::annotate(AnnotatedLine &Line) {
1999   for (SmallVectorImpl<AnnotatedLine *>::iterator I = Line.Children.begin(),
2000                                                   E = Line.Children.end();
2001        I != E; ++I) {
2002     annotate(**I);
2003   }
2004   AnnotatingParser Parser(Style, Line, Keywords);
2005   Line.Type = Parser.parseLine();
2006 
2007   // With very deep nesting, ExpressionParser uses lots of stack and the
2008   // formatting algorithm is very slow. We're not going to do a good job here
2009   // anyway - it's probably generated code being formatted by mistake.
2010   // Just skip the whole line.
2011   if (maxNestingDepth(Line) > 50)
2012     Line.Type = LT_Invalid;
2013 
2014   if (Line.Type == LT_Invalid)
2015     return;
2016 
2017   ExpressionParser ExprParser(Style, Keywords, Line);
2018   ExprParser.parse();
2019 
2020   if (Line.startsWith(TT_ObjCMethodSpecifier))
2021     Line.Type = LT_ObjCMethodDecl;
2022   else if (Line.startsWith(TT_ObjCDecl))
2023     Line.Type = LT_ObjCDecl;
2024   else if (Line.startsWith(TT_ObjCProperty))
2025     Line.Type = LT_ObjCProperty;
2026 
2027   Line.First->SpacesRequiredBefore = 1;
2028   Line.First->CanBreakBefore = Line.First->MustBreakBefore;
2029 }
2030 
2031 // This function heuristically determines whether 'Current' starts the name of a
2032 // function declaration.
2033 static bool isFunctionDeclarationName(const FormatToken &Current,
2034                                       const AnnotatedLine &Line) {
2035   auto skipOperatorName = [](const FormatToken *Next) -> const FormatToken * {
2036     for (; Next; Next = Next->Next) {
2037       if (Next->is(TT_OverloadedOperatorLParen))
2038         return Next;
2039       if (Next->is(TT_OverloadedOperator))
2040         continue;
2041       if (Next->isOneOf(tok::kw_new, tok::kw_delete)) {
2042         // For 'new[]' and 'delete[]'.
2043         if (Next->Next && Next->Next->is(tok::l_square) && Next->Next->Next &&
2044             Next->Next->Next->is(tok::r_square))
2045           Next = Next->Next->Next;
2046         continue;
2047       }
2048 
2049       break;
2050     }
2051     return nullptr;
2052   };
2053 
2054   // Find parentheses of parameter list.
2055   const FormatToken *Next = Current.Next;
2056   if (Current.is(tok::kw_operator)) {
2057     if (Current.Previous && Current.Previous->is(tok::coloncolon))
2058       return false;
2059     Next = skipOperatorName(Next);
2060   } else {
2061     if (!Current.is(TT_StartOfName) || Current.NestingLevel != 0)
2062       return false;
2063     for (; Next; Next = Next->Next) {
2064       if (Next->is(TT_TemplateOpener)) {
2065         Next = Next->MatchingParen;
2066       } else if (Next->is(tok::coloncolon)) {
2067         Next = Next->Next;
2068         if (!Next)
2069           return false;
2070         if (Next->is(tok::kw_operator)) {
2071           Next = skipOperatorName(Next->Next);
2072           break;
2073         }
2074         if (!Next->is(tok::identifier))
2075           return false;
2076       } else if (Next->is(tok::l_paren)) {
2077         break;
2078       } else {
2079         return false;
2080       }
2081     }
2082   }
2083 
2084   // Check whether parameter list can belong to a function declaration.
2085   if (!Next || !Next->is(tok::l_paren) || !Next->MatchingParen)
2086     return false;
2087   // If the lines ends with "{", this is likely an function definition.
2088   if (Line.Last->is(tok::l_brace))
2089     return true;
2090   if (Next->Next == Next->MatchingParen)
2091     return true; // Empty parentheses.
2092   // If there is an &/&& after the r_paren, this is likely a function.
2093   if (Next->MatchingParen->Next &&
2094       Next->MatchingParen->Next->is(TT_PointerOrReference))
2095     return true;
2096   for (const FormatToken *Tok = Next->Next; Tok && Tok != Next->MatchingParen;
2097        Tok = Tok->Next) {
2098     if (Tok->is(tok::l_paren) && Tok->MatchingParen) {
2099       Tok = Tok->MatchingParen;
2100       continue;
2101     }
2102     if (Tok->is(tok::kw_const) || Tok->isSimpleTypeSpecifier() ||
2103         Tok->isOneOf(TT_PointerOrReference, TT_StartOfName, tok::ellipsis))
2104       return true;
2105     if (Tok->isOneOf(tok::l_brace, tok::string_literal, TT_ObjCMethodExpr) ||
2106         Tok->Tok.isLiteral())
2107       return false;
2108   }
2109   return false;
2110 }
2111 
2112 bool TokenAnnotator::mustBreakForReturnType(const AnnotatedLine &Line) const {
2113   assert(Line.MightBeFunctionDecl);
2114 
2115   if ((Style.AlwaysBreakAfterReturnType == FormatStyle::RTBS_TopLevel ||
2116        Style.AlwaysBreakAfterReturnType ==
2117            FormatStyle::RTBS_TopLevelDefinitions) &&
2118       Line.Level > 0)
2119     return false;
2120 
2121   switch (Style.AlwaysBreakAfterReturnType) {
2122   case FormatStyle::RTBS_None:
2123     return false;
2124   case FormatStyle::RTBS_All:
2125   case FormatStyle::RTBS_TopLevel:
2126     return true;
2127   case FormatStyle::RTBS_AllDefinitions:
2128   case FormatStyle::RTBS_TopLevelDefinitions:
2129     return Line.mightBeFunctionDefinition();
2130   }
2131 
2132   return false;
2133 }
2134 
2135 void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) {
2136   for (SmallVectorImpl<AnnotatedLine *>::iterator I = Line.Children.begin(),
2137                                                   E = Line.Children.end();
2138        I != E; ++I) {
2139     calculateFormattingInformation(**I);
2140   }
2141 
2142   Line.First->TotalLength =
2143       Line.First->IsMultiline ? Style.ColumnLimit
2144                               : Line.FirstStartColumn + Line.First->ColumnWidth;
2145   FormatToken *Current = Line.First->Next;
2146   bool InFunctionDecl = Line.MightBeFunctionDecl;
2147   while (Current) {
2148     if (isFunctionDeclarationName(*Current, Line))
2149       Current->Type = TT_FunctionDeclarationName;
2150     if (Current->is(TT_LineComment)) {
2151       if (Current->Previous->BlockKind == BK_BracedInit &&
2152           Current->Previous->opensScope())
2153         Current->SpacesRequiredBefore = Style.Cpp11BracedListStyle ? 0 : 1;
2154       else
2155         Current->SpacesRequiredBefore = Style.SpacesBeforeTrailingComments;
2156 
2157       // If we find a trailing comment, iterate backwards to determine whether
2158       // it seems to relate to a specific parameter. If so, break before that
2159       // parameter to avoid changing the comment's meaning. E.g. don't move 'b'
2160       // to the previous line in:
2161       //   SomeFunction(a,
2162       //                b, // comment
2163       //                c);
2164       if (!Current->HasUnescapedNewline) {
2165         for (FormatToken *Parameter = Current->Previous; Parameter;
2166              Parameter = Parameter->Previous) {
2167           if (Parameter->isOneOf(tok::comment, tok::r_brace))
2168             break;
2169           if (Parameter->Previous && Parameter->Previous->is(tok::comma)) {
2170             if (!Parameter->Previous->is(TT_CtorInitializerComma) &&
2171                 Parameter->HasUnescapedNewline)
2172               Parameter->MustBreakBefore = true;
2173             break;
2174           }
2175         }
2176       }
2177     } else if (Current->SpacesRequiredBefore == 0 &&
2178                spaceRequiredBefore(Line, *Current)) {
2179       Current->SpacesRequiredBefore = 1;
2180     }
2181 
2182     Current->MustBreakBefore =
2183         Current->MustBreakBefore || mustBreakBefore(Line, *Current);
2184 
2185     if (!Current->MustBreakBefore && InFunctionDecl &&
2186         Current->is(TT_FunctionDeclarationName))
2187       Current->MustBreakBefore = mustBreakForReturnType(Line);
2188 
2189     Current->CanBreakBefore =
2190         Current->MustBreakBefore || canBreakBefore(Line, *Current);
2191     unsigned ChildSize = 0;
2192     if (Current->Previous->Children.size() == 1) {
2193       FormatToken &LastOfChild = *Current->Previous->Children[0]->Last;
2194       ChildSize = LastOfChild.isTrailingComment() ? Style.ColumnLimit
2195                                                   : LastOfChild.TotalLength + 1;
2196     }
2197     const FormatToken *Prev = Current->Previous;
2198     if (Current->MustBreakBefore || Prev->Children.size() > 1 ||
2199         (Prev->Children.size() == 1 &&
2200          Prev->Children[0]->First->MustBreakBefore) ||
2201         Current->IsMultiline)
2202       Current->TotalLength = Prev->TotalLength + Style.ColumnLimit;
2203     else
2204       Current->TotalLength = Prev->TotalLength + Current->ColumnWidth +
2205                              ChildSize + Current->SpacesRequiredBefore;
2206 
2207     if (Current->is(TT_CtorInitializerColon))
2208       InFunctionDecl = false;
2209 
2210     // FIXME: Only calculate this if CanBreakBefore is true once static
2211     // initializers etc. are sorted out.
2212     // FIXME: Move magic numbers to a better place.
2213 
2214     // Reduce penalty for aligning ObjC method arguments using the colon
2215     // alignment as this is the canonical way (still prefer fitting everything
2216     // into one line if possible). Trying to fit a whole expression into one
2217     // line should not force other line breaks (e.g. when ObjC method
2218     // expression is a part of other expression).
2219     Current->SplitPenalty = splitPenalty(Line, *Current, InFunctionDecl);
2220     if (Style.Language == FormatStyle::LK_ObjC &&
2221         Current->is(TT_SelectorName) && Current->ParameterIndex > 0) {
2222       if (Current->ParameterIndex == 1)
2223         Current->SplitPenalty += 5 * Current->BindingStrength;
2224     } else {
2225       Current->SplitPenalty += 20 * Current->BindingStrength;
2226     }
2227 
2228     Current = Current->Next;
2229   }
2230 
2231   calculateUnbreakableTailLengths(Line);
2232   unsigned IndentLevel = Line.Level;
2233   for (Current = Line.First; Current != nullptr; Current = Current->Next) {
2234     if (Current->Role)
2235       Current->Role->precomputeFormattingInfos(Current);
2236     if (Current->MatchingParen &&
2237         Current->MatchingParen->opensBlockOrBlockTypeList(Style)) {
2238       assert(IndentLevel > 0);
2239       --IndentLevel;
2240     }
2241     Current->IndentLevel = IndentLevel;
2242     if (Current->opensBlockOrBlockTypeList(Style))
2243       ++IndentLevel;
2244   }
2245 
2246   LLVM_DEBUG({ printDebugInfo(Line); });
2247 }
2248 
2249 void TokenAnnotator::calculateUnbreakableTailLengths(AnnotatedLine &Line) {
2250   unsigned UnbreakableTailLength = 0;
2251   FormatToken *Current = Line.Last;
2252   while (Current) {
2253     Current->UnbreakableTailLength = UnbreakableTailLength;
2254     if (Current->CanBreakBefore ||
2255         Current->isOneOf(tok::comment, tok::string_literal)) {
2256       UnbreakableTailLength = 0;
2257     } else {
2258       UnbreakableTailLength +=
2259           Current->ColumnWidth + Current->SpacesRequiredBefore;
2260     }
2261     Current = Current->Previous;
2262   }
2263 }
2264 
2265 unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
2266                                       const FormatToken &Tok,
2267                                       bool InFunctionDecl) {
2268   const FormatToken &Left = *Tok.Previous;
2269   const FormatToken &Right = Tok;
2270 
2271   if (Left.is(tok::semi))
2272     return 0;
2273 
2274   if (Style.Language == FormatStyle::LK_Java) {
2275     if (Right.isOneOf(Keywords.kw_extends, Keywords.kw_throws))
2276       return 1;
2277     if (Right.is(Keywords.kw_implements))
2278       return 2;
2279     if (Left.is(tok::comma) && Left.NestingLevel == 0)
2280       return 3;
2281   } else if (Style.Language == FormatStyle::LK_JavaScript) {
2282     if (Right.is(Keywords.kw_function) && Left.isNot(tok::comma))
2283       return 100;
2284     if (Left.is(TT_JsTypeColon))
2285       return 35;
2286     if ((Left.is(TT_TemplateString) && Left.TokenText.endswith("${")) ||
2287         (Right.is(TT_TemplateString) && Right.TokenText.startswith("}")))
2288       return 100;
2289     // Prefer breaking call chains (".foo") over empty "{}", "[]" or "()".
2290     if (Left.opensScope() && Right.closesScope())
2291       return 200;
2292   }
2293 
2294   if (Right.is(tok::identifier) && Right.Next && Right.Next->is(TT_DictLiteral))
2295     return 1;
2296   if (Right.is(tok::l_square)) {
2297     if (Style.Language == FormatStyle::LK_Proto)
2298       return 1;
2299     if (Left.is(tok::r_square))
2300       return 200;
2301     // Slightly prefer formatting local lambda definitions like functions.
2302     if (Right.is(TT_LambdaLSquare) && Left.is(tok::equal))
2303       return 35;
2304     if (!Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
2305                        TT_ArrayInitializerLSquare,
2306                        TT_DesignatedInitializerLSquare, TT_AttributeSquare))
2307       return 500;
2308   }
2309 
2310   if (Left.is(tok::coloncolon) ||
2311       (Right.is(tok::period) && Style.Language == FormatStyle::LK_Proto))
2312     return 500;
2313   if (Right.isOneOf(TT_StartOfName, TT_FunctionDeclarationName) ||
2314       Right.is(tok::kw_operator)) {
2315     if (Line.startsWith(tok::kw_for) && Right.PartOfMultiVariableDeclStmt)
2316       return 3;
2317     if (Left.is(TT_StartOfName))
2318       return 110;
2319     if (InFunctionDecl && Right.NestingLevel == 0)
2320       return Style.PenaltyReturnTypeOnItsOwnLine;
2321     return 200;
2322   }
2323   if (Right.is(TT_PointerOrReference))
2324     return 190;
2325   if (Right.is(TT_LambdaArrow))
2326     return 110;
2327   if (Left.is(tok::equal) && Right.is(tok::l_brace))
2328     return 160;
2329   if (Left.is(TT_CastRParen))
2330     return 100;
2331   if (Left.isOneOf(tok::kw_class, tok::kw_struct))
2332     return 5000;
2333   if (Left.is(tok::comment))
2334     return 1000;
2335 
2336   if (Left.isOneOf(TT_RangeBasedForLoopColon, TT_InheritanceColon,
2337                    TT_CtorInitializerColon))
2338     return 2;
2339 
2340   if (Right.isMemberAccess()) {
2341     // Breaking before the "./->" of a chained call/member access is reasonably
2342     // cheap, as formatting those with one call per line is generally
2343     // desirable. In particular, it should be cheaper to break before the call
2344     // than it is to break inside a call's parameters, which could lead to weird
2345     // "hanging" indents. The exception is the very last "./->" to support this
2346     // frequent pattern:
2347     //
2348     //   aaaaaaaa.aaaaaaaa.bbbbbbb().ccccccccccccccccccccc(
2349     //       dddddddd);
2350     //
2351     // which might otherwise be blown up onto many lines. Here, clang-format
2352     // won't produce "hanging" indents anyway as there is no other trailing
2353     // call.
2354     //
2355     // Also apply higher penalty is not a call as that might lead to a wrapping
2356     // like:
2357     //
2358     //   aaaaaaa
2359     //       .aaaaaaaaa.bbbbbbbb(cccccccc);
2360     return !Right.NextOperator || !Right.NextOperator->Previous->closesScope()
2361                ? 150
2362                : 35;
2363   }
2364 
2365   if (Right.is(TT_TrailingAnnotation) &&
2366       (!Right.Next || Right.Next->isNot(tok::l_paren))) {
2367     // Moving trailing annotations to the next line is fine for ObjC method
2368     // declarations.
2369     if (Line.startsWith(TT_ObjCMethodSpecifier))
2370       return 10;
2371     // Generally, breaking before a trailing annotation is bad unless it is
2372     // function-like. It seems to be especially preferable to keep standard
2373     // annotations (i.e. "const", "final" and "override") on the same line.
2374     // Use a slightly higher penalty after ")" so that annotations like
2375     // "const override" are kept together.
2376     bool is_short_annotation = Right.TokenText.size() < 10;
2377     return (Left.is(tok::r_paren) ? 100 : 120) + (is_short_annotation ? 50 : 0);
2378   }
2379 
2380   // In for-loops, prefer breaking at ',' and ';'.
2381   if (Line.startsWith(tok::kw_for) && Left.is(tok::equal))
2382     return 4;
2383 
2384   // In Objective-C method expressions, prefer breaking before "param:" over
2385   // breaking after it.
2386   if (Right.is(TT_SelectorName))
2387     return 0;
2388   if (Left.is(tok::colon) && Left.is(TT_ObjCMethodExpr))
2389     return Line.MightBeFunctionDecl ? 50 : 500;
2390 
2391   // In Objective-C type declarations, avoid breaking after the category's
2392   // open paren (we'll prefer breaking after the protocol list's opening
2393   // angle bracket, if present).
2394   if (Line.Type == LT_ObjCDecl && Left.is(tok::l_paren) && Left.Previous &&
2395       Left.Previous->isOneOf(tok::identifier, tok::greater))
2396     return 500;
2397 
2398   if (Left.is(tok::l_paren) && InFunctionDecl &&
2399       Style.AlignAfterOpenBracket != FormatStyle::BAS_DontAlign)
2400     return 100;
2401   if (Left.is(tok::l_paren) && Left.Previous &&
2402       (Left.Previous->isOneOf(tok::kw_if, tok::kw_for) ||
2403        Left.Previous->endsSequence(tok::kw_constexpr, tok::kw_if)))
2404     return 1000;
2405   if (Left.is(tok::equal) && InFunctionDecl)
2406     return 110;
2407   if (Right.is(tok::r_brace))
2408     return 1;
2409   if (Left.is(TT_TemplateOpener))
2410     return 100;
2411   if (Left.opensScope()) {
2412     if (Style.AlignAfterOpenBracket == FormatStyle::BAS_DontAlign)
2413       return 0;
2414     if (Left.is(tok::l_brace) && !Style.Cpp11BracedListStyle)
2415       return 19;
2416     return Left.ParameterCount > 1 ? Style.PenaltyBreakBeforeFirstCallParameter
2417                                    : 19;
2418   }
2419   if (Left.is(TT_JavaAnnotation))
2420     return 50;
2421 
2422   if (Left.isOneOf(tok::plus, tok::comma) && Left.Previous &&
2423       Left.Previous->isLabelString() &&
2424       (Left.NextOperator || Left.OperatorIndex != 0))
2425     return 50;
2426   if (Right.is(tok::plus) && Left.isLabelString() &&
2427       (Right.NextOperator || Right.OperatorIndex != 0))
2428     return 25;
2429   if (Left.is(tok::comma))
2430     return 1;
2431   if (Right.is(tok::lessless) && Left.isLabelString() &&
2432       (Right.NextOperator || Right.OperatorIndex != 1))
2433     return 25;
2434   if (Right.is(tok::lessless)) {
2435     // Breaking at a << is really cheap.
2436     if (!Left.is(tok::r_paren) || Right.OperatorIndex > 0)
2437       // Slightly prefer to break before the first one in log-like statements.
2438       return 2;
2439     return 1;
2440   }
2441   if (Left.ClosesTemplateDeclaration)
2442     return Style.PenaltyBreakTemplateDeclaration;
2443   if (Left.is(TT_ConditionalExpr))
2444     return prec::Conditional;
2445   prec::Level Level = Left.getPrecedence();
2446   if (Level == prec::Unknown)
2447     Level = Right.getPrecedence();
2448   if (Level == prec::Assignment)
2449     return Style.PenaltyBreakAssignment;
2450   if (Level != prec::Unknown)
2451     return Level;
2452 
2453   return 3;
2454 }
2455 
2456 bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
2457                                           const FormatToken &Left,
2458                                           const FormatToken &Right) {
2459   if (Left.is(tok::kw_return) && Right.isNot(tok::semi))
2460     return true;
2461   if (Left.is(Keywords.kw_assert) && Style.Language == FormatStyle::LK_Java)
2462     return true;
2463   if (Style.ObjCSpaceAfterProperty && Line.Type == LT_ObjCProperty &&
2464       Left.Tok.getObjCKeywordID() == tok::objc_property)
2465     return true;
2466   if (Right.is(tok::hashhash))
2467     return Left.is(tok::hash);
2468   if (Left.isOneOf(tok::hashhash, tok::hash))
2469     return Right.is(tok::hash);
2470   if (Left.is(tok::l_paren) && Right.is(tok::r_paren))
2471     return Style.SpaceInEmptyParentheses;
2472   if (Left.is(tok::l_paren) || Right.is(tok::r_paren))
2473     return (Right.is(TT_CastRParen) ||
2474             (Left.MatchingParen && Left.MatchingParen->is(TT_CastRParen)))
2475                ? Style.SpacesInCStyleCastParentheses
2476                : Style.SpacesInParentheses;
2477   if (Right.isOneOf(tok::semi, tok::comma))
2478     return false;
2479   if (Right.is(tok::less) && Line.Type == LT_ObjCDecl) {
2480     bool IsLightweightGeneric = Right.MatchingParen &&
2481                                 Right.MatchingParen->Next &&
2482                                 Right.MatchingParen->Next->is(tok::colon);
2483     return !IsLightweightGeneric && Style.ObjCSpaceBeforeProtocolList;
2484   }
2485   if (Right.is(tok::less) && Left.is(tok::kw_template))
2486     return Style.SpaceAfterTemplateKeyword;
2487   if (Left.isOneOf(tok::exclaim, tok::tilde))
2488     return false;
2489   if (Left.is(tok::at) &&
2490       Right.isOneOf(tok::identifier, tok::string_literal, tok::char_constant,
2491                     tok::numeric_constant, tok::l_paren, tok::l_brace,
2492                     tok::kw_true, tok::kw_false))
2493     return false;
2494   if (Left.is(tok::colon))
2495     return !Left.is(TT_ObjCMethodExpr);
2496   if (Left.is(tok::coloncolon))
2497     return false;
2498   if (Left.is(tok::less) || Right.isOneOf(tok::greater, tok::less)) {
2499     if (Style.Language == FormatStyle::LK_TextProto ||
2500         (Style.Language == FormatStyle::LK_Proto &&
2501          (Left.is(TT_DictLiteral) || Right.is(TT_DictLiteral)))) {
2502       // Format empty list as `<>`.
2503       if (Left.is(tok::less) && Right.is(tok::greater))
2504         return false;
2505       return !Style.Cpp11BracedListStyle;
2506     }
2507     return false;
2508   }
2509   if (Right.is(tok::ellipsis))
2510     return Left.Tok.isLiteral() || (Left.is(tok::identifier) && Left.Previous &&
2511                                     Left.Previous->is(tok::kw_case));
2512   if (Left.is(tok::l_square) && Right.is(tok::amp))
2513     return false;
2514   if (Right.is(TT_PointerOrReference)) {
2515     if (Left.is(tok::r_paren) && Line.MightBeFunctionDecl) {
2516       if (!Left.MatchingParen)
2517         return true;
2518       FormatToken *TokenBeforeMatchingParen =
2519           Left.MatchingParen->getPreviousNonComment();
2520       if (!TokenBeforeMatchingParen ||
2521           !TokenBeforeMatchingParen->isOneOf(tok::kw_typeof, tok::kw_decltype))
2522         return true;
2523     }
2524     return (Left.Tok.isLiteral() ||
2525             (!Left.isOneOf(TT_PointerOrReference, tok::l_paren) &&
2526              (Style.PointerAlignment != FormatStyle::PAS_Left ||
2527               (Line.IsMultiVariableDeclStmt &&
2528                (Left.NestingLevel == 0 ||
2529                 (Left.NestingLevel == 1 && Line.First->is(tok::kw_for)))))));
2530   }
2531   if (Right.is(TT_FunctionTypeLParen) && Left.isNot(tok::l_paren) &&
2532       (!Left.is(TT_PointerOrReference) ||
2533        (Style.PointerAlignment != FormatStyle::PAS_Right &&
2534         !Line.IsMultiVariableDeclStmt)))
2535     return true;
2536   if (Left.is(TT_PointerOrReference))
2537     return Right.Tok.isLiteral() || Right.is(TT_BlockComment) ||
2538            (Right.isOneOf(Keywords.kw_override, Keywords.kw_final) &&
2539             !Right.is(TT_StartOfName)) ||
2540            (Right.is(tok::l_brace) && Right.BlockKind == BK_Block) ||
2541            (!Right.isOneOf(TT_PointerOrReference, TT_ArraySubscriptLSquare,
2542                            tok::l_paren) &&
2543             (Style.PointerAlignment != FormatStyle::PAS_Right &&
2544              !Line.IsMultiVariableDeclStmt) &&
2545             Left.Previous &&
2546             !Left.Previous->isOneOf(tok::l_paren, tok::coloncolon));
2547   if (Right.is(tok::star) && Left.is(tok::l_paren))
2548     return false;
2549   const auto SpaceRequiredForArrayInitializerLSquare =
2550       [](const FormatToken &LSquareTok, const FormatStyle &Style) {
2551         return Style.SpacesInContainerLiterals ||
2552                ((Style.Language == FormatStyle::LK_Proto ||
2553                  Style.Language == FormatStyle::LK_TextProto) &&
2554                 !Style.Cpp11BracedListStyle &&
2555                 LSquareTok.endsSequence(tok::l_square, tok::colon,
2556                                         TT_SelectorName));
2557       };
2558   if (Left.is(tok::l_square))
2559     return (Left.is(TT_ArrayInitializerLSquare) && Right.isNot(tok::r_square) &&
2560             SpaceRequiredForArrayInitializerLSquare(Left, Style)) ||
2561            (Left.isOneOf(TT_ArraySubscriptLSquare,
2562                          TT_StructuredBindingLSquare) &&
2563             Style.SpacesInSquareBrackets && Right.isNot(tok::r_square));
2564   if (Right.is(tok::r_square))
2565     return Right.MatchingParen &&
2566            ((Right.MatchingParen->is(TT_ArrayInitializerLSquare) &&
2567              SpaceRequiredForArrayInitializerLSquare(*Right.MatchingParen,
2568                                                      Style)) ||
2569             (Style.SpacesInSquareBrackets &&
2570              Right.MatchingParen->isOneOf(TT_ArraySubscriptLSquare,
2571                                           TT_StructuredBindingLSquare)) ||
2572             Right.MatchingParen->is(TT_AttributeParen));
2573   if (Right.is(tok::l_square) &&
2574       !Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
2575                      TT_DesignatedInitializerLSquare,
2576                      TT_StructuredBindingLSquare, TT_AttributeSquare) &&
2577       !Left.isOneOf(tok::numeric_constant, TT_DictLiteral))
2578     return false;
2579   if (Left.is(tok::l_brace) && Right.is(tok::r_brace))
2580     return !Left.Children.empty(); // No spaces in "{}".
2581   if ((Left.is(tok::l_brace) && Left.BlockKind != BK_Block) ||
2582       (Right.is(tok::r_brace) && Right.MatchingParen &&
2583        Right.MatchingParen->BlockKind != BK_Block))
2584     return !Style.Cpp11BracedListStyle;
2585   if (Left.is(TT_BlockComment))
2586     // No whitespace in x(/*foo=*/1), except for JavaScript.
2587     return Style.Language == FormatStyle::LK_JavaScript ||
2588            !Left.TokenText.endswith("=*/");
2589   if (Right.is(tok::l_paren)) {
2590     if ((Left.is(tok::r_paren) && Left.is(TT_AttributeParen)) ||
2591         (Left.is(tok::r_square) && Left.is(TT_AttributeSquare)))
2592       return true;
2593     return Line.Type == LT_ObjCDecl || Left.is(tok::semi) ||
2594            (Style.SpaceBeforeParens != FormatStyle::SBPO_Never &&
2595             (Left.isOneOf(tok::kw_if, tok::pp_elif, tok::kw_for, tok::kw_while,
2596                           tok::kw_switch, tok::kw_case, TT_ForEachMacro,
2597                           TT_ObjCForIn) ||
2598              Left.endsSequence(tok::kw_constexpr, tok::kw_if) ||
2599              (Left.isOneOf(tok::kw_try, Keywords.kw___except, tok::kw_catch,
2600                            tok::kw_new, tok::kw_delete) &&
2601               (!Left.Previous || Left.Previous->isNot(tok::period))))) ||
2602            (Style.SpaceBeforeParens == FormatStyle::SBPO_Always &&
2603             (Left.is(tok::identifier) || Left.isFunctionLikeKeyword() ||
2604              Left.is(tok::r_paren) ||
2605              (Left.is(tok::r_square) && Left.MatchingParen &&
2606               Left.MatchingParen->is(TT_LambdaLSquare))) &&
2607             Line.Type != LT_PreprocessorDirective);
2608   }
2609   if (Left.is(tok::at) && Right.Tok.getObjCKeywordID() != tok::objc_not_keyword)
2610     return false;
2611   if (Right.is(TT_UnaryOperator))
2612     return !Left.isOneOf(tok::l_paren, tok::l_square, tok::at) &&
2613            (Left.isNot(tok::colon) || Left.isNot(TT_ObjCMethodExpr));
2614   if ((Left.isOneOf(tok::identifier, tok::greater, tok::r_square,
2615                     tok::r_paren) ||
2616        Left.isSimpleTypeSpecifier()) &&
2617       Right.is(tok::l_brace) && Right.getNextNonComment() &&
2618       Right.BlockKind != BK_Block)
2619     return false;
2620   if (Left.is(tok::period) || Right.is(tok::period))
2621     return false;
2622   if (Right.is(tok::hash) && Left.is(tok::identifier) && Left.TokenText == "L")
2623     return false;
2624   if (Left.is(TT_TemplateCloser) && Left.MatchingParen &&
2625       Left.MatchingParen->Previous &&
2626       (Left.MatchingParen->Previous->is(tok::period) ||
2627        Left.MatchingParen->Previous->is(tok::coloncolon)))
2628     // Java call to generic function with explicit type:
2629     // A.<B<C<...>>>DoSomething();
2630     // A::<B<C<...>>>DoSomething();  // With a Java 8 method reference.
2631     return false;
2632   if (Left.is(TT_TemplateCloser) && Right.is(tok::l_square))
2633     return false;
2634   if (Left.is(tok::l_brace) && Left.endsSequence(TT_DictLiteral, tok::at))
2635     // Objective-C dictionary literal -> no space after opening brace.
2636     return false;
2637   if (Right.is(tok::r_brace) && Right.MatchingParen &&
2638       Right.MatchingParen->endsSequence(TT_DictLiteral, tok::at))
2639     // Objective-C dictionary literal -> no space before closing brace.
2640     return false;
2641   return true;
2642 }
2643 
2644 bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
2645                                          const FormatToken &Right) {
2646   const FormatToken &Left = *Right.Previous;
2647   if (Right.Tok.getIdentifierInfo() && Left.Tok.getIdentifierInfo())
2648     return true; // Never ever merge two identifiers.
2649   if (Style.isCpp()) {
2650     if (Left.is(tok::kw_operator))
2651       return Right.is(tok::coloncolon);
2652     if (Right.is(tok::l_brace) && Right.BlockKind == BK_BracedInit &&
2653         !Left.opensScope() && Style.SpaceBeforeCpp11BracedList)
2654       return true;
2655   } else if (Style.Language == FormatStyle::LK_Proto ||
2656              Style.Language == FormatStyle::LK_TextProto) {
2657     if (Right.is(tok::period) &&
2658         Left.isOneOf(Keywords.kw_optional, Keywords.kw_required,
2659                      Keywords.kw_repeated, Keywords.kw_extend))
2660       return true;
2661     if (Right.is(tok::l_paren) &&
2662         Left.isOneOf(Keywords.kw_returns, Keywords.kw_option))
2663       return true;
2664     if (Right.isOneOf(tok::l_brace, tok::less) && Left.is(TT_SelectorName))
2665       return true;
2666     // Slashes occur in text protocol extension syntax: [type/type] { ... }.
2667     if (Left.is(tok::slash) || Right.is(tok::slash))
2668       return false;
2669     if (Left.MatchingParen &&
2670         Left.MatchingParen->is(TT_ProtoExtensionLSquare) &&
2671         Right.isOneOf(tok::l_brace, tok::less))
2672       return !Style.Cpp11BracedListStyle;
2673     // A percent is probably part of a formatting specification, such as %lld.
2674     if (Left.is(tok::percent))
2675       return false;
2676     // Preserve the existence of a space before a percent for cases like 0x%04x
2677     // and "%d %d"
2678     if (Left.is(tok::numeric_constant) && Right.is(tok::percent))
2679       return Right.WhitespaceRange.getEnd() != Right.WhitespaceRange.getBegin();
2680   } else if (Style.Language == FormatStyle::LK_JavaScript || Style.isCSharp()) {
2681     if (Left.is(TT_JsFatArrow))
2682       return true;
2683     // for await ( ...
2684     if (Right.is(tok::l_paren) && Left.is(Keywords.kw_await) && Left.Previous &&
2685         Left.Previous->is(tok::kw_for))
2686       return true;
2687     if (Left.is(Keywords.kw_async) && Right.is(tok::l_paren) &&
2688         Right.MatchingParen) {
2689       const FormatToken *Next = Right.MatchingParen->getNextNonComment();
2690       // An async arrow function, for example: `x = async () => foo();`,
2691       // as opposed to calling a function called async: `x = async();`
2692       if (Next && Next->is(TT_JsFatArrow))
2693         return true;
2694     }
2695     if ((Left.is(TT_TemplateString) && Left.TokenText.endswith("${")) ||
2696         (Right.is(TT_TemplateString) && Right.TokenText.startswith("}")))
2697       return false;
2698     // In tagged template literals ("html`bar baz`"), there is no space between
2699     // the tag identifier and the template string. getIdentifierInfo makes sure
2700     // that the identifier is not a pseudo keyword like `yield`, either.
2701     if (Left.is(tok::identifier) && Keywords.IsJavaScriptIdentifier(Left) &&
2702         Right.is(TT_TemplateString))
2703       return false;
2704     if (Right.is(tok::star) &&
2705         Left.isOneOf(Keywords.kw_function, Keywords.kw_yield))
2706       return false;
2707     if (Right.isOneOf(tok::l_brace, tok::l_square) &&
2708         Left.isOneOf(Keywords.kw_function, Keywords.kw_yield,
2709                      Keywords.kw_extends, Keywords.kw_implements))
2710       return true;
2711     if (Right.is(tok::l_paren)) {
2712       // JS methods can use some keywords as names (e.g. `delete()`).
2713       if (Line.MustBeDeclaration && Left.Tok.getIdentifierInfo())
2714         return false;
2715       // Valid JS method names can include keywords, e.g. `foo.delete()` or
2716       // `bar.instanceof()`. Recognize call positions by preceding period.
2717       if (Left.Previous && Left.Previous->is(tok::period) &&
2718           Left.Tok.getIdentifierInfo())
2719         return false;
2720       // Additional unary JavaScript operators that need a space after.
2721       if (Left.isOneOf(tok::kw_throw, Keywords.kw_await, Keywords.kw_typeof,
2722                        tok::kw_void))
2723         return true;
2724     }
2725     if ((Left.isOneOf(Keywords.kw_let, Keywords.kw_var, Keywords.kw_in,
2726                       tok::kw_const) ||
2727          // "of" is only a keyword if it appears after another identifier
2728          // (e.g. as "const x of y" in a for loop), or after a destructuring
2729          // operation (const [x, y] of z, const {a, b} of c).
2730          (Left.is(Keywords.kw_of) && Left.Previous &&
2731           (Left.Previous->Tok.is(tok::identifier) ||
2732            Left.Previous->isOneOf(tok::r_square, tok::r_brace)))) &&
2733         (!Left.Previous || !Left.Previous->is(tok::period)))
2734       return true;
2735     if (Left.isOneOf(tok::kw_for, Keywords.kw_as) && Left.Previous &&
2736         Left.Previous->is(tok::period) && Right.is(tok::l_paren))
2737       return false;
2738     if (Left.is(Keywords.kw_as) &&
2739         Right.isOneOf(tok::l_square, tok::l_brace, tok::l_paren))
2740       return true;
2741     if (Left.is(tok::kw_default) && Left.Previous &&
2742         Left.Previous->is(tok::kw_export))
2743       return true;
2744     if (Left.is(Keywords.kw_is) && Right.is(tok::l_brace))
2745       return true;
2746     if (Right.isOneOf(TT_JsTypeColon, TT_JsTypeOptionalQuestion))
2747       return false;
2748     if (Left.is(TT_JsTypeOperator) || Right.is(TT_JsTypeOperator))
2749       return false;
2750     if ((Left.is(tok::l_brace) || Right.is(tok::r_brace)) &&
2751         Line.First->isOneOf(Keywords.kw_import, tok::kw_export))
2752       return false;
2753     if (Left.is(tok::ellipsis))
2754       return false;
2755     if (Left.is(TT_TemplateCloser) &&
2756         !Right.isOneOf(tok::equal, tok::l_brace, tok::comma, tok::l_square,
2757                        Keywords.kw_implements, Keywords.kw_extends))
2758       // Type assertions ('<type>expr') are not followed by whitespace. Other
2759       // locations that should have whitespace following are identified by the
2760       // above set of follower tokens.
2761       return false;
2762     if (Right.is(TT_JsNonNullAssertion))
2763       return false;
2764     if (Left.is(TT_JsNonNullAssertion) &&
2765         Right.isOneOf(Keywords.kw_as, Keywords.kw_in))
2766       return true; // "x! as string", "x! in y"
2767   } else if (Style.Language == FormatStyle::LK_Java) {
2768     if (Left.is(tok::r_square) && Right.is(tok::l_brace))
2769       return true;
2770     if (Left.is(Keywords.kw_synchronized) && Right.is(tok::l_paren))
2771       return Style.SpaceBeforeParens != FormatStyle::SBPO_Never;
2772     if ((Left.isOneOf(tok::kw_static, tok::kw_public, tok::kw_private,
2773                       tok::kw_protected) ||
2774          Left.isOneOf(Keywords.kw_final, Keywords.kw_abstract,
2775                       Keywords.kw_native)) &&
2776         Right.is(TT_TemplateOpener))
2777       return true;
2778   }
2779   if (Left.is(TT_ImplicitStringLiteral))
2780     return Right.WhitespaceRange.getBegin() != Right.WhitespaceRange.getEnd();
2781   if (Line.Type == LT_ObjCMethodDecl) {
2782     if (Left.is(TT_ObjCMethodSpecifier))
2783       return true;
2784     if (Left.is(tok::r_paren) && canBeObjCSelectorComponent(Right))
2785       // Don't space between ')' and <id> or ')' and 'new'. 'new' is not a
2786       // keyword in Objective-C, and '+ (instancetype)new;' is a standard class
2787       // method declaration.
2788       return false;
2789   }
2790   if (Line.Type == LT_ObjCProperty &&
2791       (Right.is(tok::equal) || Left.is(tok::equal)))
2792     return false;
2793 
2794   if (Right.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow) ||
2795       Left.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow))
2796     return true;
2797   if (Right.is(TT_OverloadedOperatorLParen))
2798     return Style.SpaceBeforeParens == FormatStyle::SBPO_Always;
2799   if (Left.is(tok::comma))
2800     return true;
2801   if (Right.is(tok::comma))
2802     return false;
2803   if (Right.is(TT_ObjCBlockLParen))
2804     return true;
2805   if (Right.is(TT_CtorInitializerColon))
2806     return Style.SpaceBeforeCtorInitializerColon;
2807   if (Right.is(TT_InheritanceColon) && !Style.SpaceBeforeInheritanceColon)
2808     return false;
2809   if (Right.is(TT_RangeBasedForLoopColon) &&
2810       !Style.SpaceBeforeRangeBasedForLoopColon)
2811     return false;
2812   if (Right.is(tok::colon)) {
2813     if (Line.First->isOneOf(tok::kw_case, tok::kw_default) ||
2814         !Right.getNextNonComment() || Right.getNextNonComment()->is(tok::semi))
2815       return false;
2816     if (Right.is(TT_ObjCMethodExpr))
2817       return false;
2818     if (Left.is(tok::question))
2819       return false;
2820     if (Right.is(TT_InlineASMColon) && Left.is(tok::coloncolon))
2821       return false;
2822     if (Right.is(TT_DictLiteral))
2823       return Style.SpacesInContainerLiterals;
2824     if (Right.is(TT_AttributeColon))
2825       return false;
2826     return true;
2827   }
2828   if (Left.is(TT_UnaryOperator))
2829     return Right.is(TT_BinaryOperator);
2830 
2831   // If the next token is a binary operator or a selector name, we have
2832   // incorrectly classified the parenthesis as a cast. FIXME: Detect correctly.
2833   if (Left.is(TT_CastRParen))
2834     return Style.SpaceAfterCStyleCast ||
2835            Right.isOneOf(TT_BinaryOperator, TT_SelectorName);
2836 
2837   if (Left.is(tok::greater) && Right.is(tok::greater)) {
2838     if (Style.Language == FormatStyle::LK_TextProto ||
2839         (Style.Language == FormatStyle::LK_Proto && Left.is(TT_DictLiteral)))
2840       return !Style.Cpp11BracedListStyle;
2841     return Right.is(TT_TemplateCloser) && Left.is(TT_TemplateCloser) &&
2842            (Style.Standard != FormatStyle::LS_Cpp11 || Style.SpacesInAngles);
2843   }
2844   if (Right.isOneOf(tok::arrow, tok::arrowstar, tok::periodstar) ||
2845       Left.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar) ||
2846       (Right.is(tok::period) && Right.isNot(TT_DesignatedInitializerPeriod)))
2847     return false;
2848   if (!Style.SpaceBeforeAssignmentOperators &&
2849       Right.getPrecedence() == prec::Assignment)
2850     return false;
2851   if (Style.Language == FormatStyle::LK_Java && Right.is(tok::coloncolon) &&
2852       (Left.is(tok::identifier) || Left.is(tok::kw_this)))
2853     return false;
2854   if (Right.is(tok::coloncolon) && Left.is(tok::identifier))
2855     // Generally don't remove existing spaces between an identifier and "::".
2856     // The identifier might actually be a macro name such as ALWAYS_INLINE. If
2857     // this turns out to be too lenient, add analysis of the identifier itself.
2858     return Right.WhitespaceRange.getBegin() != Right.WhitespaceRange.getEnd();
2859   if (Right.is(tok::coloncolon) && !Left.isOneOf(tok::l_brace, tok::comment))
2860     return (Left.is(TT_TemplateOpener) &&
2861             Style.Standard == FormatStyle::LS_Cpp03) ||
2862            !(Left.isOneOf(tok::l_paren, tok::r_paren, tok::l_square,
2863                           tok::kw___super, TT_TemplateCloser,
2864                           TT_TemplateOpener)) ||
2865            (Left.is(tok ::l_paren) && Style.SpacesInParentheses);
2866   if ((Left.is(TT_TemplateOpener)) != (Right.is(TT_TemplateCloser)))
2867     return Style.SpacesInAngles;
2868   // Space before TT_StructuredBindingLSquare.
2869   if (Right.is(TT_StructuredBindingLSquare))
2870     return !Left.isOneOf(tok::amp, tok::ampamp) ||
2871            Style.PointerAlignment != FormatStyle::PAS_Right;
2872   // Space before & or && following a TT_StructuredBindingLSquare.
2873   if (Right.Next && Right.Next->is(TT_StructuredBindingLSquare) &&
2874       Right.isOneOf(tok::amp, tok::ampamp))
2875     return Style.PointerAlignment != FormatStyle::PAS_Left;
2876   if ((Right.is(TT_BinaryOperator) && !Left.is(tok::l_paren)) ||
2877       (Left.isOneOf(TT_BinaryOperator, TT_ConditionalExpr) &&
2878        !Right.is(tok::r_paren)))
2879     return true;
2880   if (Left.is(TT_TemplateCloser) && Right.is(tok::l_paren) &&
2881       Right.isNot(TT_FunctionTypeLParen))
2882     return Style.SpaceBeforeParens == FormatStyle::SBPO_Always;
2883   if (Right.is(TT_TemplateOpener) && Left.is(tok::r_paren) &&
2884       Left.MatchingParen && Left.MatchingParen->is(TT_OverloadedOperatorLParen))
2885     return false;
2886   if (Right.is(tok::less) && Left.isNot(tok::l_paren) &&
2887       Line.startsWith(tok::hash))
2888     return true;
2889   if (Right.is(TT_TrailingUnaryOperator))
2890     return false;
2891   if (Left.is(TT_RegexLiteral))
2892     return false;
2893   return spaceRequiredBetween(Line, Left, Right);
2894 }
2895 
2896 // Returns 'true' if 'Tok' is a brace we'd want to break before in Allman style.
2897 static bool isAllmanBrace(const FormatToken &Tok) {
2898   return Tok.is(tok::l_brace) && Tok.BlockKind == BK_Block &&
2899          !Tok.isOneOf(TT_ObjCBlockLBrace, TT_DictLiteral);
2900 }
2901 
2902 bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
2903                                      const FormatToken &Right) {
2904   const FormatToken &Left = *Right.Previous;
2905   if (Right.NewlinesBefore > 1 && Style.MaxEmptyLinesToKeep > 0)
2906     return true;
2907 
2908   if (Style.Language == FormatStyle::LK_JavaScript) {
2909     // FIXME: This might apply to other languages and token kinds.
2910     if (Right.is(tok::string_literal) && Left.is(tok::plus) && Left.Previous &&
2911         Left.Previous->is(tok::string_literal))
2912       return true;
2913     if (Left.is(TT_DictLiteral) && Left.is(tok::l_brace) && Line.Level == 0 &&
2914         Left.Previous && Left.Previous->is(tok::equal) &&
2915         Line.First->isOneOf(tok::identifier, Keywords.kw_import, tok::kw_export,
2916                             tok::kw_const) &&
2917         // kw_var/kw_let are pseudo-tokens that are tok::identifier, so match
2918         // above.
2919         !Line.First->isOneOf(Keywords.kw_var, Keywords.kw_let))
2920       // Object literals on the top level of a file are treated as "enum-style".
2921       // Each key/value pair is put on a separate line, instead of bin-packing.
2922       return true;
2923     if (Left.is(tok::l_brace) && Line.Level == 0 &&
2924         (Line.startsWith(tok::kw_enum) ||
2925          Line.startsWith(tok::kw_const, tok::kw_enum) ||
2926          Line.startsWith(tok::kw_export, tok::kw_enum) ||
2927          Line.startsWith(tok::kw_export, tok::kw_const, tok::kw_enum)))
2928       // JavaScript top-level enum key/value pairs are put on separate lines
2929       // instead of bin-packing.
2930       return true;
2931     if (Right.is(tok::r_brace) && Left.is(tok::l_brace) &&
2932         !Left.Children.empty())
2933       // Support AllowShortFunctionsOnASingleLine for JavaScript.
2934       return Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_None ||
2935              Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_Empty ||
2936              (Left.NestingLevel == 0 && Line.Level == 0 &&
2937               Style.AllowShortFunctionsOnASingleLine &
2938                   FormatStyle::SFS_InlineOnly);
2939   } else if (Style.Language == FormatStyle::LK_Java) {
2940     if (Right.is(tok::plus) && Left.is(tok::string_literal) && Right.Next &&
2941         Right.Next->is(tok::string_literal))
2942       return true;
2943   } else if (Style.Language == FormatStyle::LK_Cpp ||
2944              Style.Language == FormatStyle::LK_ObjC ||
2945              Style.Language == FormatStyle::LK_Proto ||
2946              Style.Language == FormatStyle::LK_TableGen ||
2947              Style.Language == FormatStyle::LK_TextProto) {
2948     if (Left.isStringLiteral() && Right.isStringLiteral())
2949       return true;
2950   }
2951 
2952   // If the last token before a '}', ']', or ')' is a comma or a trailing
2953   // comment, the intention is to insert a line break after it in order to make
2954   // shuffling around entries easier. Import statements, especially in
2955   // JavaScript, can be an exception to this rule.
2956   if (Style.JavaScriptWrapImports || Line.Type != LT_ImportStatement) {
2957     const FormatToken *BeforeClosingBrace = nullptr;
2958     if ((Left.isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) ||
2959          (Style.Language == FormatStyle::LK_JavaScript &&
2960           Left.is(tok::l_paren))) &&
2961         Left.BlockKind != BK_Block && Left.MatchingParen)
2962       BeforeClosingBrace = Left.MatchingParen->Previous;
2963     else if (Right.MatchingParen &&
2964              (Right.MatchingParen->isOneOf(tok::l_brace,
2965                                            TT_ArrayInitializerLSquare) ||
2966               (Style.Language == FormatStyle::LK_JavaScript &&
2967                Right.MatchingParen->is(tok::l_paren))))
2968       BeforeClosingBrace = &Left;
2969     if (BeforeClosingBrace && (BeforeClosingBrace->is(tok::comma) ||
2970                                BeforeClosingBrace->isTrailingComment()))
2971       return true;
2972   }
2973 
2974   if (Right.is(tok::comment))
2975     return Left.BlockKind != BK_BracedInit &&
2976            Left.isNot(TT_CtorInitializerColon) &&
2977            (Right.NewlinesBefore > 0 && Right.HasUnescapedNewline);
2978   if (Left.isTrailingComment())
2979     return true;
2980   if (Right.Previous->IsUnterminatedLiteral)
2981     return true;
2982   if (Right.is(tok::lessless) && Right.Next &&
2983       Right.Previous->is(tok::string_literal) &&
2984       Right.Next->is(tok::string_literal))
2985     return true;
2986   if (Right.Previous->ClosesTemplateDeclaration &&
2987       Right.Previous->MatchingParen &&
2988       Right.Previous->MatchingParen->NestingLevel == 0 &&
2989       Style.AlwaysBreakTemplateDeclarations == FormatStyle::BTDS_Yes)
2990     return true;
2991   if (Right.is(TT_CtorInitializerComma) &&
2992       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma &&
2993       !Style.ConstructorInitializerAllOnOneLineOrOnePerLine)
2994     return true;
2995   if (Right.is(TT_CtorInitializerColon) &&
2996       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma &&
2997       !Style.ConstructorInitializerAllOnOneLineOrOnePerLine)
2998     return true;
2999   // Break only if we have multiple inheritance.
3000   if (Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma &&
3001       Right.is(TT_InheritanceComma))
3002     return true;
3003   if (Right.is(tok::string_literal) && Right.TokenText.startswith("R\""))
3004     // Multiline raw string literals are special wrt. line breaks. The author
3005     // has made a deliberate choice and might have aligned the contents of the
3006     // string literal accordingly. Thus, we try keep existing line breaks.
3007     return Right.IsMultiline && Right.NewlinesBefore > 0;
3008   if ((Right.Previous->is(tok::l_brace) ||
3009        (Right.Previous->is(tok::less) && Right.Previous->Previous &&
3010         Right.Previous->Previous->is(tok::equal))) &&
3011       Right.NestingLevel == 1 && Style.Language == FormatStyle::LK_Proto) {
3012     // Don't put enums or option definitions onto single lines in protocol
3013     // buffers.
3014     return true;
3015   }
3016   if (Right.is(TT_InlineASMBrace))
3017     return Right.HasUnescapedNewline;
3018   if (isAllmanBrace(Left) || isAllmanBrace(Right))
3019     return (Line.startsWith(tok::kw_enum) && Style.BraceWrapping.AfterEnum) ||
3020            (Line.startsWith(tok::kw_typedef, tok::kw_enum) &&
3021             Style.BraceWrapping.AfterEnum) ||
3022            (Line.startsWith(tok::kw_class) && Style.BraceWrapping.AfterClass) ||
3023            (Line.startsWith(tok::kw_struct) && Style.BraceWrapping.AfterStruct);
3024   if (Left.is(TT_ObjCBlockLBrace) && !Style.AllowShortBlocksOnASingleLine)
3025     return true;
3026 
3027   // Put multiple C# attributes on a new line.
3028   if (Style.isCSharp() &&
3029       ((Left.is(TT_AttributeSquare) && Left.is(tok::r_square)) ||
3030        (Left.is(tok::r_square) && Right.is(TT_AttributeSquare) &&
3031         Right.is(tok::l_square))))
3032     return true;
3033 
3034   // Put multiple Java annotation on a new line.
3035   if ((Style.Language == FormatStyle::LK_Java ||
3036        Style.Language == FormatStyle::LK_JavaScript) &&
3037       Left.is(TT_LeadingJavaAnnotation) &&
3038       Right.isNot(TT_LeadingJavaAnnotation) && Right.isNot(tok::l_paren) &&
3039       (Line.Last->is(tok::l_brace) || Style.BreakAfterJavaFieldAnnotations))
3040     return true;
3041 
3042   if (Right.is(TT_ProtoExtensionLSquare))
3043     return true;
3044 
3045   // In text proto instances if a submessage contains at least 2 entries and at
3046   // least one of them is a submessage, like A { ... B { ... } ... },
3047   // put all of the entries of A on separate lines by forcing the selector of
3048   // the submessage B to be put on a newline.
3049   //
3050   // Example: these can stay on one line:
3051   // a { scalar_1: 1 scalar_2: 2 }
3052   // a { b { key: value } }
3053   //
3054   // and these entries need to be on a new line even if putting them all in one
3055   // line is under the column limit:
3056   // a {
3057   //   scalar: 1
3058   //   b { key: value }
3059   // }
3060   //
3061   // We enforce this by breaking before a submessage field that has previous
3062   // siblings, *and* breaking before a field that follows a submessage field.
3063   //
3064   // Be careful to exclude the case  [proto.ext] { ... } since the `]` is
3065   // the TT_SelectorName there, but we don't want to break inside the brackets.
3066   //
3067   // Another edge case is @submessage { key: value }, which is a common
3068   // substitution placeholder. In this case we want to keep `@` and `submessage`
3069   // together.
3070   //
3071   // We ensure elsewhere that extensions are always on their own line.
3072   if ((Style.Language == FormatStyle::LK_Proto ||
3073        Style.Language == FormatStyle::LK_TextProto) &&
3074       Right.is(TT_SelectorName) && !Right.is(tok::r_square) && Right.Next) {
3075     // Keep `@submessage` together in:
3076     // @submessage { key: value }
3077     if (Right.Previous && Right.Previous->is(tok::at))
3078       return false;
3079     // Look for the scope opener after selector in cases like:
3080     // selector { ...
3081     // selector: { ...
3082     // selector: @base { ...
3083     FormatToken *LBrace = Right.Next;
3084     if (LBrace && LBrace->is(tok::colon)) {
3085       LBrace = LBrace->Next;
3086       if (LBrace && LBrace->is(tok::at)) {
3087         LBrace = LBrace->Next;
3088         if (LBrace)
3089           LBrace = LBrace->Next;
3090       }
3091     }
3092     if (LBrace &&
3093         // The scope opener is one of {, [, <:
3094         // selector { ... }
3095         // selector [ ... ]
3096         // selector < ... >
3097         //
3098         // In case of selector { ... }, the l_brace is TT_DictLiteral.
3099         // In case of an empty selector {}, the l_brace is not TT_DictLiteral,
3100         // so we check for immediately following r_brace.
3101         ((LBrace->is(tok::l_brace) &&
3102           (LBrace->is(TT_DictLiteral) ||
3103            (LBrace->Next && LBrace->Next->is(tok::r_brace)))) ||
3104          LBrace->is(TT_ArrayInitializerLSquare) || LBrace->is(tok::less))) {
3105       // If Left.ParameterCount is 0, then this submessage entry is not the
3106       // first in its parent submessage, and we want to break before this entry.
3107       // If Left.ParameterCount is greater than 0, then its parent submessage
3108       // might contain 1 or more entries and we want to break before this entry
3109       // if it contains at least 2 entries. We deal with this case later by
3110       // detecting and breaking before the next entry in the parent submessage.
3111       if (Left.ParameterCount == 0)
3112         return true;
3113       // However, if this submessage is the first entry in its parent
3114       // submessage, Left.ParameterCount might be 1 in some cases.
3115       // We deal with this case later by detecting an entry
3116       // following a closing paren of this submessage.
3117     }
3118 
3119     // If this is an entry immediately following a submessage, it will be
3120     // preceded by a closing paren of that submessage, like in:
3121     //     left---.  .---right
3122     //            v  v
3123     // sub: { ... } key: value
3124     // If there was a comment between `}` an `key` above, then `key` would be
3125     // put on a new line anyways.
3126     if (Left.isOneOf(tok::r_brace, tok::greater, tok::r_square))
3127       return true;
3128   }
3129 
3130   // Deal with lambda arguments in C++ - we want consistent line breaks whether
3131   // they happen to be at arg0, arg1 or argN. The selection is a bit nuanced
3132   // as aggressive line breaks are placed when the lambda is not the last arg.
3133   if ((Style.Language == FormatStyle::LK_Cpp ||
3134        Style.Language == FormatStyle::LK_ObjC) &&
3135       Left.is(tok::l_paren) && Left.BlockParameterCount > 0 &&
3136       !Right.isOneOf(tok::l_paren, TT_LambdaLSquare)) {
3137     // Multiple lambdas in the same function call force line breaks.
3138     if (Left.BlockParameterCount > 1)
3139       return true;
3140 
3141     // A lambda followed by another arg forces a line break.
3142     if (!Left.Role)
3143       return false;
3144     auto Comma = Left.Role->lastComma();
3145     if (!Comma)
3146       return false;
3147     auto Next = Comma->getNextNonComment();
3148     if (!Next)
3149       return false;
3150     if (!Next->isOneOf(TT_LambdaLSquare, tok::l_brace, tok::caret))
3151       return true;
3152   }
3153 
3154   return false;
3155 }
3156 
3157 bool TokenAnnotator::canBreakBefore(const AnnotatedLine &Line,
3158                                     const FormatToken &Right) {
3159   const FormatToken &Left = *Right.Previous;
3160 
3161   // Language-specific stuff.
3162   if (Style.Language == FormatStyle::LK_Java) {
3163     if (Left.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
3164                      Keywords.kw_implements))
3165       return false;
3166     if (Right.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
3167                       Keywords.kw_implements))
3168       return true;
3169   } else if (Style.Language == FormatStyle::LK_JavaScript) {
3170     const FormatToken *NonComment = Right.getPreviousNonComment();
3171     if (NonComment &&
3172         NonComment->isOneOf(
3173             tok::kw_return, Keywords.kw_yield, tok::kw_continue, tok::kw_break,
3174             tok::kw_throw, Keywords.kw_interface, Keywords.kw_type,
3175             tok::kw_static, tok::kw_public, tok::kw_private, tok::kw_protected,
3176             Keywords.kw_readonly, Keywords.kw_abstract, Keywords.kw_get,
3177             Keywords.kw_set, Keywords.kw_async, Keywords.kw_await))
3178       return false; // Otherwise automatic semicolon insertion would trigger.
3179     if (Right.NestingLevel == 0 &&
3180         (Left.Tok.getIdentifierInfo() ||
3181          Left.isOneOf(tok::r_square, tok::r_paren)) &&
3182         Right.isOneOf(tok::l_square, tok::l_paren))
3183       return false; // Otherwise automatic semicolon insertion would trigger.
3184     if (Left.is(TT_JsFatArrow) && Right.is(tok::l_brace))
3185       return false;
3186     if (Left.is(TT_JsTypeColon))
3187       return true;
3188     // Don't wrap between ":" and "!" of a strict prop init ("field!: type;").
3189     if (Left.is(tok::exclaim) && Right.is(tok::colon))
3190       return false;
3191     // Look for is type annotations like:
3192     // function f(): a is B { ... }
3193     // Do not break before is in these cases.
3194     if (Right.is(Keywords.kw_is)) {
3195       const FormatToken *Next = Right.getNextNonComment();
3196       // If `is` is followed by a colon, it's likely that it's a dict key, so
3197       // ignore it for this check.
3198       // For example this is common in Polymer:
3199       // Polymer({
3200       //   is: 'name',
3201       //   ...
3202       // });
3203       if (!Next || !Next->is(tok::colon))
3204         return false;
3205     }
3206     if (Left.is(Keywords.kw_in))
3207       return Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None;
3208     if (Right.is(Keywords.kw_in))
3209       return Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None;
3210     if (Right.is(Keywords.kw_as))
3211       return false; // must not break before as in 'x as type' casts
3212     if (Right.isOneOf(Keywords.kw_extends, Keywords.kw_infer)) {
3213       // extends and infer can appear as keywords in conditional types:
3214       //   https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-8.html#conditional-types
3215       // do not break before them, as the expressions are subject to ASI.
3216       return false;
3217     }
3218     if (Left.is(Keywords.kw_as))
3219       return true;
3220     if (Left.is(TT_JsNonNullAssertion))
3221       return true;
3222     if (Left.is(Keywords.kw_declare) &&
3223         Right.isOneOf(Keywords.kw_module, tok::kw_namespace,
3224                       Keywords.kw_function, tok::kw_class, tok::kw_enum,
3225                       Keywords.kw_interface, Keywords.kw_type, Keywords.kw_var,
3226                       Keywords.kw_let, tok::kw_const))
3227       // See grammar for 'declare' statements at:
3228       // https://github.com/Microsoft/TypeScript/blob/master/doc/spec.md#A.10
3229       return false;
3230     if (Left.isOneOf(Keywords.kw_module, tok::kw_namespace) &&
3231         Right.isOneOf(tok::identifier, tok::string_literal))
3232       return false; // must not break in "module foo { ...}"
3233     if (Right.is(TT_TemplateString) && Right.closesScope())
3234       return false;
3235     // Don't split tagged template literal so there is a break between the tag
3236     // identifier and template string.
3237     if (Left.is(tok::identifier) && Right.is(TT_TemplateString)) {
3238       return false;
3239     }
3240     if (Left.is(TT_TemplateString) && Left.opensScope())
3241       return true;
3242   }
3243 
3244   if (Left.is(tok::at))
3245     return false;
3246   if (Left.Tok.getObjCKeywordID() == tok::objc_interface)
3247     return false;
3248   if (Left.isOneOf(TT_JavaAnnotation, TT_LeadingJavaAnnotation))
3249     return !Right.is(tok::l_paren);
3250   if (Right.is(TT_PointerOrReference))
3251     return Line.IsMultiVariableDeclStmt ||
3252            (Style.PointerAlignment == FormatStyle::PAS_Right &&
3253             (!Right.Next || Right.Next->isNot(TT_FunctionDeclarationName)));
3254   if (Right.isOneOf(TT_StartOfName, TT_FunctionDeclarationName) ||
3255       Right.is(tok::kw_operator))
3256     return true;
3257   if (Left.is(TT_PointerOrReference))
3258     return false;
3259   if (Right.isTrailingComment())
3260     // We rely on MustBreakBefore being set correctly here as we should not
3261     // change the "binding" behavior of a comment.
3262     // The first comment in a braced lists is always interpreted as belonging to
3263     // the first list element. Otherwise, it should be placed outside of the
3264     // list.
3265     return Left.BlockKind == BK_BracedInit ||
3266            (Left.is(TT_CtorInitializerColon) &&
3267             Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon);
3268   if (Left.is(tok::question) && Right.is(tok::colon))
3269     return false;
3270   if (Right.is(TT_ConditionalExpr) || Right.is(tok::question))
3271     return Style.BreakBeforeTernaryOperators;
3272   if (Left.is(TT_ConditionalExpr) || Left.is(tok::question))
3273     return !Style.BreakBeforeTernaryOperators;
3274   if (Left.is(TT_InheritanceColon))
3275     return Style.BreakInheritanceList == FormatStyle::BILS_AfterColon;
3276   if (Right.is(TT_InheritanceColon))
3277     return Style.BreakInheritanceList != FormatStyle::BILS_AfterColon;
3278   if (Right.is(TT_ObjCMethodExpr) && !Right.is(tok::r_square) &&
3279       Left.isNot(TT_SelectorName))
3280     return true;
3281 
3282   if (Right.is(tok::colon) &&
3283       !Right.isOneOf(TT_CtorInitializerColon, TT_InlineASMColon))
3284     return false;
3285   if (Left.is(tok::colon) && Left.isOneOf(TT_DictLiteral, TT_ObjCMethodExpr)) {
3286     if (Style.Language == FormatStyle::LK_Proto ||
3287         Style.Language == FormatStyle::LK_TextProto) {
3288       if (!Style.AlwaysBreakBeforeMultilineStrings && Right.isStringLiteral())
3289         return false;
3290       // Prevent cases like:
3291       //
3292       // submessage:
3293       //     { key: valueeeeeeeeeeee }
3294       //
3295       // when the snippet does not fit into one line.
3296       // Prefer:
3297       //
3298       // submessage: {
3299       //   key: valueeeeeeeeeeee
3300       // }
3301       //
3302       // instead, even if it is longer by one line.
3303       //
3304       // Note that this allows allows the "{" to go over the column limit
3305       // when the column limit is just between ":" and "{", but that does
3306       // not happen too often and alternative formattings in this case are
3307       // not much better.
3308       //
3309       // The code covers the cases:
3310       //
3311       // submessage: { ... }
3312       // submessage: < ... >
3313       // repeated: [ ... ]
3314       if (((Right.is(tok::l_brace) || Right.is(tok::less)) &&
3315            Right.is(TT_DictLiteral)) ||
3316           Right.is(TT_ArrayInitializerLSquare))
3317         return false;
3318     }
3319     return true;
3320   }
3321   if (Right.is(tok::r_square) && Right.MatchingParen &&
3322       Right.MatchingParen->is(TT_ProtoExtensionLSquare))
3323     return false;
3324   if (Right.is(TT_SelectorName) || (Right.is(tok::identifier) && Right.Next &&
3325                                     Right.Next->is(TT_ObjCMethodExpr)))
3326     return Left.isNot(tok::period); // FIXME: Properly parse ObjC calls.
3327   if (Left.is(tok::r_paren) && Line.Type == LT_ObjCProperty)
3328     return true;
3329   if (Left.ClosesTemplateDeclaration || Left.is(TT_FunctionAnnotationRParen))
3330     return true;
3331   if (Right.isOneOf(TT_RangeBasedForLoopColon, TT_OverloadedOperatorLParen,
3332                     TT_OverloadedOperator))
3333     return false;
3334   if (Left.is(TT_RangeBasedForLoopColon))
3335     return true;
3336   if (Right.is(TT_RangeBasedForLoopColon))
3337     return false;
3338   if (Left.is(TT_TemplateCloser) && Right.is(TT_TemplateOpener))
3339     return true;
3340   if (Left.isOneOf(TT_TemplateCloser, TT_UnaryOperator) ||
3341       Left.is(tok::kw_operator))
3342     return false;
3343   if (Left.is(tok::equal) && !Right.isOneOf(tok::kw_default, tok::kw_delete) &&
3344       Line.Type == LT_VirtualFunctionDecl && Left.NestingLevel == 0)
3345     return false;
3346   if (Left.is(tok::equal) && Right.is(tok::l_brace) &&
3347       !Style.Cpp11BracedListStyle)
3348     return false;
3349   if (Left.is(tok::l_paren) && Left.is(TT_AttributeParen))
3350     return false;
3351   if (Left.is(tok::l_paren) && Left.Previous &&
3352       (Left.Previous->isOneOf(TT_BinaryOperator, TT_CastRParen)))
3353     return false;
3354   if (Right.is(TT_ImplicitStringLiteral))
3355     return false;
3356 
3357   if (Right.is(tok::r_paren) || Right.is(TT_TemplateCloser))
3358     return false;
3359   if (Right.is(tok::r_square) && Right.MatchingParen &&
3360       Right.MatchingParen->is(TT_LambdaLSquare))
3361     return false;
3362 
3363   // We only break before r_brace if there was a corresponding break before
3364   // the l_brace, which is tracked by BreakBeforeClosingBrace.
3365   if (Right.is(tok::r_brace))
3366     return Right.MatchingParen && Right.MatchingParen->BlockKind == BK_Block;
3367 
3368   // Allow breaking after a trailing annotation, e.g. after a method
3369   // declaration.
3370   if (Left.is(TT_TrailingAnnotation))
3371     return !Right.isOneOf(tok::l_brace, tok::semi, tok::equal, tok::l_paren,
3372                           tok::less, tok::coloncolon);
3373 
3374   if (Right.is(tok::kw___attribute) ||
3375       (Right.is(tok::l_square) && Right.is(TT_AttributeSquare)))
3376     return true;
3377 
3378   if (Left.is(tok::identifier) && Right.is(tok::string_literal))
3379     return true;
3380 
3381   if (Right.is(tok::identifier) && Right.Next && Right.Next->is(TT_DictLiteral))
3382     return true;
3383 
3384   if (Left.is(TT_CtorInitializerColon))
3385     return Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon;
3386   if (Right.is(TT_CtorInitializerColon))
3387     return Style.BreakConstructorInitializers != FormatStyle::BCIS_AfterColon;
3388   if (Left.is(TT_CtorInitializerComma) &&
3389       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma)
3390     return false;
3391   if (Right.is(TT_CtorInitializerComma) &&
3392       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma)
3393     return true;
3394   if (Left.is(TT_InheritanceComma) &&
3395       Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma)
3396     return false;
3397   if (Right.is(TT_InheritanceComma) &&
3398       Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma)
3399     return true;
3400   if ((Left.is(tok::greater) && Right.is(tok::greater)) ||
3401       (Left.is(tok::less) && Right.is(tok::less)))
3402     return false;
3403   if (Right.is(TT_BinaryOperator) &&
3404       Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None &&
3405       (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_All ||
3406        Right.getPrecedence() != prec::Assignment))
3407     return true;
3408   if (Left.is(TT_ArrayInitializerLSquare))
3409     return true;
3410   if (Right.is(tok::kw_typename) && Left.isNot(tok::kw_const))
3411     return true;
3412   if ((Left.isBinaryOperator() || Left.is(TT_BinaryOperator)) &&
3413       !Left.isOneOf(tok::arrowstar, tok::lessless) &&
3414       Style.BreakBeforeBinaryOperators != FormatStyle::BOS_All &&
3415       (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None ||
3416        Left.getPrecedence() == prec::Assignment))
3417     return true;
3418   if ((Left.is(TT_AttributeSquare) && Right.is(tok::l_square)) ||
3419       (Left.is(tok::r_square) && Right.is(TT_AttributeSquare)))
3420     return false;
3421   return Left.isOneOf(tok::comma, tok::coloncolon, tok::semi, tok::l_brace,
3422                       tok::kw_class, tok::kw_struct, tok::comment) ||
3423          Right.isMemberAccess() ||
3424          Right.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow, tok::lessless,
3425                        tok::colon, tok::l_square, tok::at) ||
3426          (Left.is(tok::r_paren) &&
3427           Right.isOneOf(tok::identifier, tok::kw_const)) ||
3428          (Left.is(tok::l_paren) && !Right.is(tok::r_paren)) ||
3429          (Left.is(TT_TemplateOpener) && !Right.is(TT_TemplateCloser));
3430 }
3431 
3432 void TokenAnnotator::printDebugInfo(const AnnotatedLine &Line) {
3433   llvm::errs() << "AnnotatedTokens(L=" << Line.Level << "):\n";
3434   const FormatToken *Tok = Line.First;
3435   while (Tok) {
3436     llvm::errs() << " M=" << Tok->MustBreakBefore
3437                  << " C=" << Tok->CanBreakBefore
3438                  << " T=" << getTokenTypeName(Tok->Type)
3439                  << " S=" << Tok->SpacesRequiredBefore
3440                  << " B=" << Tok->BlockParameterCount
3441                  << " BK=" << Tok->BlockKind << " P=" << Tok->SplitPenalty
3442                  << " Name=" << Tok->Tok.getName() << " L=" << Tok->TotalLength
3443                  << " PPK=" << Tok->PackingKind << " FakeLParens=";
3444     for (unsigned i = 0, e = Tok->FakeLParens.size(); i != e; ++i)
3445       llvm::errs() << Tok->FakeLParens[i] << "/";
3446     llvm::errs() << " FakeRParens=" << Tok->FakeRParens;
3447     llvm::errs() << " II=" << Tok->Tok.getIdentifierInfo();
3448     llvm::errs() << " Text='" << Tok->TokenText << "'\n";
3449     if (!Tok->Next)
3450       assert(Tok == Line.Last);
3451     Tok = Tok->Next;
3452   }
3453   llvm::errs() << "----\n";
3454 }
3455 
3456 } // namespace format
3457 } // namespace clang
3458