1//===- llvm/Support/YAMLTraits.h --------------------------------*- C++ -*-===//
2//
3//                             The LLVM Linker
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef LLVM_SUPPORT_YAMLTRAITS_H
11#define LLVM_SUPPORT_YAMLTRAITS_H
12
13#include "llvm/ADT/Optional.h"
14#include "llvm/ADT/SmallVector.h"
15#include "llvm/ADT/StringMap.h"
16#include "llvm/ADT/StringRef.h"
17#include "llvm/ADT/StringSwitch.h"
18#include "llvm/ADT/Twine.h"
19#include "llvm/Support/Compiler.h"
20#include "llvm/Support/Endian.h"
21#include "llvm/Support/Regex.h"
22#include "llvm/Support/SourceMgr.h"
23#include "llvm/Support/YAMLParser.h"
24#include "llvm/Support/raw_ostream.h"
25#include <system_error>
26
27namespace llvm {
28namespace yaml {
29
30/// This class should be specialized by any type that needs to be converted
31/// to/from a YAML mapping.  For example:
32///
33///     struct MappingTraits<MyStruct> {
34///       static void mapping(IO &io, MyStruct &s) {
35///         io.mapRequired("name", s.name);
36///         io.mapRequired("size", s.size);
37///         io.mapOptional("age",  s.age);
38///       }
39///     };
40template<class T>
41struct MappingTraits {
42  // Must provide:
43  // static void mapping(IO &io, T &fields);
44  // Optionally may provide:
45  // static StringRef validate(IO &io, T &fields);
46  //
47  // The optional flow flag will cause generated YAML to use a flow mapping
48  // (e.g. { a: 0, b: 1 }):
49  // static const bool flow = true;
50};
51
52/// This class should be specialized by any integral type that converts
53/// to/from a YAML scalar where there is a one-to-one mapping between
54/// in-memory values and a string in YAML.  For example:
55///
56///     struct ScalarEnumerationTraits<Colors> {
57///         static void enumeration(IO &io, Colors &value) {
58///           io.enumCase(value, "red",   cRed);
59///           io.enumCase(value, "blue",  cBlue);
60///           io.enumCase(value, "green", cGreen);
61///         }
62///       };
63template<typename T>
64struct ScalarEnumerationTraits {
65  // Must provide:
66  // static void enumeration(IO &io, T &value);
67};
68
69/// This class should be specialized by any integer type that is a union
70/// of bit values and the YAML representation is a flow sequence of
71/// strings.  For example:
72///
73///      struct ScalarBitSetTraits<MyFlags> {
74///        static void bitset(IO &io, MyFlags &value) {
75///          io.bitSetCase(value, "big",   flagBig);
76///          io.bitSetCase(value, "flat",  flagFlat);
77///          io.bitSetCase(value, "round", flagRound);
78///        }
79///      };
80template<typename T>
81struct ScalarBitSetTraits {
82  // Must provide:
83  // static void bitset(IO &io, T &value);
84};
85
86/// This class should be specialized by type that requires custom conversion
87/// to/from a yaml scalar.  For example:
88///
89///    template<>
90///    struct ScalarTraits<MyType> {
91///      static void output(const MyType &val, void*, llvm::raw_ostream &out) {
92///        // stream out custom formatting
93///        out << llvm::format("%x", val);
94///      }
95///      static StringRef input(StringRef scalar, void*, MyType &value) {
96///        // parse scalar and set `value`
97///        // return empty string on success, or error string
98///        return StringRef();
99///      }
100///      static bool mustQuote(StringRef) { return true; }
101///    };
102template<typename T>
103struct ScalarTraits {
104  // Must provide:
105  //
106  // Function to write the value as a string:
107  //static void output(const T &value, void *ctxt, llvm::raw_ostream &out);
108  //
109  // Function to convert a string to a value.  Returns the empty
110  // StringRef on success or an error string if string is malformed:
111  //static StringRef input(StringRef scalar, void *ctxt, T &value);
112  //
113  // Function to determine if the value should be quoted.
114  //static bool mustQuote(StringRef);
115};
116
117
118/// This class should be specialized by type that requires custom conversion
119/// to/from a YAML literal block scalar. For example:
120///
121///    template <>
122///    struct BlockScalarTraits<MyType> {
123///      static void output(const MyType &Value, void*, llvm::raw_ostream &Out)
124///      {
125///        // stream out custom formatting
126///        Out << Val;
127///      }
128///      static StringRef input(StringRef Scalar, void*, MyType &Value) {
129///        // parse scalar and set `value`
130///        // return empty string on success, or error string
131///        return StringRef();
132///      }
133///    };
134template <typename T>
135struct BlockScalarTraits {
136  // Must provide:
137  //
138  // Function to write the value as a string:
139  // static void output(const T &Value, void *ctx, llvm::raw_ostream &Out);
140  //
141  // Function to convert a string to a value.  Returns the empty
142  // StringRef on success or an error string if string is malformed:
143  // static StringRef input(StringRef Scalar, void *ctxt, T &Value);
144};
145
146/// This class should be specialized by any type that needs to be converted
147/// to/from a YAML sequence.  For example:
148///
149///    template<>
150///    struct SequenceTraits< std::vector<MyType> > {
151///      static size_t size(IO &io, std::vector<MyType> &seq) {
152///        return seq.size();
153///      }
154///      static MyType& element(IO &, std::vector<MyType> &seq, size_t index) {
155///        if ( index >= seq.size() )
156///          seq.resize(index+1);
157///        return seq[index];
158///      }
159///    };
160template<typename T>
161struct SequenceTraits {
162  // Must provide:
163  // static size_t size(IO &io, T &seq);
164  // static T::value_type& element(IO &io, T &seq, size_t index);
165  //
166  // The following is option and will cause generated YAML to use
167  // a flow sequence (e.g. [a,b,c]).
168  // static const bool flow = true;
169};
170
171/// This class should be specialized by any type that needs to be converted
172/// to/from a list of YAML documents.
173template<typename T>
174struct DocumentListTraits {
175  // Must provide:
176  // static size_t size(IO &io, T &seq);
177  // static T::value_type& element(IO &io, T &seq, size_t index);
178};
179
180// Only used by compiler if both template types are the same
181template <typename T, T>
182struct SameType;
183
184// Only used for better diagnostics of missing traits
185template <typename T>
186struct MissingTrait;
187
188// Test if ScalarEnumerationTraits<T> is defined on type T.
189template <class T>
190struct has_ScalarEnumerationTraits
191{
192  typedef void (*Signature_enumeration)(class IO&, T&);
193
194  template <typename U>
195  static char test(SameType<Signature_enumeration, &U::enumeration>*);
196
197  template <typename U>
198  static double test(...);
199
200public:
201  static bool const value =
202    (sizeof(test<ScalarEnumerationTraits<T> >(nullptr)) == 1);
203};
204
205// Test if ScalarBitSetTraits<T> is defined on type T.
206template <class T>
207struct has_ScalarBitSetTraits
208{
209  typedef void (*Signature_bitset)(class IO&, T&);
210
211  template <typename U>
212  static char test(SameType<Signature_bitset, &U::bitset>*);
213
214  template <typename U>
215  static double test(...);
216
217public:
218  static bool const value = (sizeof(test<ScalarBitSetTraits<T> >(nullptr)) == 1);
219};
220
221// Test if ScalarTraits<T> is defined on type T.
222template <class T>
223struct has_ScalarTraits
224{
225  typedef StringRef (*Signature_input)(StringRef, void*, T&);
226  typedef void (*Signature_output)(const T&, void*, llvm::raw_ostream&);
227  typedef bool (*Signature_mustQuote)(StringRef);
228
229  template <typename U>
230  static char test(SameType<Signature_input, &U::input> *,
231                   SameType<Signature_output, &U::output> *,
232                   SameType<Signature_mustQuote, &U::mustQuote> *);
233
234  template <typename U>
235  static double test(...);
236
237public:
238  static bool const value =
239      (sizeof(test<ScalarTraits<T>>(nullptr, nullptr, nullptr)) == 1);
240};
241
242// Test if BlockScalarTraits<T> is defined on type T.
243template <class T>
244struct has_BlockScalarTraits
245{
246  typedef StringRef (*Signature_input)(StringRef, void *, T &);
247  typedef void (*Signature_output)(const T &, void *, llvm::raw_ostream &);
248
249  template <typename U>
250  static char test(SameType<Signature_input, &U::input> *,
251                   SameType<Signature_output, &U::output> *);
252
253  template <typename U>
254  static double test(...);
255
256public:
257  static bool const value =
258      (sizeof(test<BlockScalarTraits<T>>(nullptr, nullptr)) == 1);
259};
260
261// Test if MappingTraits<T> is defined on type T.
262template <class T>
263struct has_MappingTraits
264{
265  typedef void (*Signature_mapping)(class IO&, T&);
266
267  template <typename U>
268  static char test(SameType<Signature_mapping, &U::mapping>*);
269
270  template <typename U>
271  static double test(...);
272
273public:
274  static bool const value = (sizeof(test<MappingTraits<T> >(nullptr)) == 1);
275};
276
277// Test if MappingTraits<T>::validate() is defined on type T.
278template <class T>
279struct has_MappingValidateTraits
280{
281  typedef StringRef (*Signature_validate)(class IO&, T&);
282
283  template <typename U>
284  static char test(SameType<Signature_validate, &U::validate>*);
285
286  template <typename U>
287  static double test(...);
288
289public:
290  static bool const value = (sizeof(test<MappingTraits<T> >(nullptr)) == 1);
291};
292
293// Test if SequenceTraits<T> is defined on type T.
294template <class T>
295struct has_SequenceMethodTraits
296{
297  typedef size_t (*Signature_size)(class IO&, T&);
298
299  template <typename U>
300  static char test(SameType<Signature_size, &U::size>*);
301
302  template <typename U>
303  static double test(...);
304
305public:
306  static bool const value =  (sizeof(test<SequenceTraits<T> >(nullptr)) == 1);
307};
308
309// has_FlowTraits<int> will cause an error with some compilers because
310// it subclasses int.  Using this wrapper only instantiates the
311// real has_FlowTraits only if the template type is a class.
312template <typename T, bool Enabled = std::is_class<T>::value>
313class has_FlowTraits
314{
315public:
316   static const bool value = false;
317};
318
319// Some older gcc compilers don't support straight forward tests
320// for members, so test for ambiguity cause by the base and derived
321// classes both defining the member.
322template <class T>
323struct has_FlowTraits<T, true>
324{
325  struct Fallback { bool flow; };
326  struct Derived : T, Fallback { };
327
328  template<typename C>
329  static char (&f(SameType<bool Fallback::*, &C::flow>*))[1];
330
331  template<typename C>
332  static char (&f(...))[2];
333
334public:
335  static bool const value = sizeof(f<Derived>(nullptr)) == 2;
336};
337
338// Test if SequenceTraits<T> is defined on type T
339template<typename T>
340struct has_SequenceTraits : public std::integral_constant<bool,
341                                      has_SequenceMethodTraits<T>::value > { };
342
343// Test if DocumentListTraits<T> is defined on type T
344template <class T>
345struct has_DocumentListTraits
346{
347  typedef size_t (*Signature_size)(class IO&, T&);
348
349  template <typename U>
350  static char test(SameType<Signature_size, &U::size>*);
351
352  template <typename U>
353  static double test(...);
354
355public:
356  static bool const value = (sizeof(test<DocumentListTraits<T> >(nullptr))==1);
357};
358
359inline bool isNumber(StringRef S) {
360  static const char OctalChars[] = "01234567";
361  if (S.startswith("0") &&
362      S.drop_front().find_first_not_of(OctalChars) == StringRef::npos)
363    return true;
364
365  if (S.startswith("0o") &&
366      S.drop_front(2).find_first_not_of(OctalChars) == StringRef::npos)
367    return true;
368
369  static const char HexChars[] = "0123456789abcdefABCDEF";
370  if (S.startswith("0x") &&
371      S.drop_front(2).find_first_not_of(HexChars) == StringRef::npos)
372    return true;
373
374  static const char DecChars[] = "0123456789";
375  if (S.find_first_not_of(DecChars) == StringRef::npos)
376    return true;
377
378  if (S.equals(".inf") || S.equals(".Inf") || S.equals(".INF"))
379    return true;
380
381  Regex FloatMatcher("^(\\.[0-9]+|[0-9]+(\\.[0-9]*)?)([eE][-+]?[0-9]+)?$");
382  if (FloatMatcher.match(S))
383    return true;
384
385  return false;
386}
387
388inline bool isNumeric(StringRef S) {
389  if ((S.front() == '-' || S.front() == '+') && isNumber(S.drop_front()))
390    return true;
391
392  if (isNumber(S))
393    return true;
394
395  if (S.equals(".nan") || S.equals(".NaN") || S.equals(".NAN"))
396    return true;
397
398  return false;
399}
400
401inline bool isNull(StringRef S) {
402  return S.equals("null") || S.equals("Null") || S.equals("NULL") ||
403         S.equals("~");
404}
405
406inline bool isBool(StringRef S) {
407  return S.equals("true") || S.equals("True") || S.equals("TRUE") ||
408         S.equals("false") || S.equals("False") || S.equals("FALSE");
409}
410
411inline bool needsQuotes(StringRef S) {
412  if (S.empty())
413    return true;
414  if (isspace(S.front()) || isspace(S.back()))
415    return true;
416  if (S.front() == ',')
417    return true;
418
419  static const char ScalarSafeChars[] =
420      "abcdefghijklmnopqrstuvwxyz"
421      "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-/^., \t";
422  if (S.find_first_not_of(ScalarSafeChars) != StringRef::npos)
423    return true;
424
425  if (isNull(S))
426    return true;
427  if (isBool(S))
428    return true;
429  if (isNumeric(S))
430    return true;
431
432  return false;
433}
434
435template<typename T>
436struct missingTraits : public std::integral_constant<bool,
437                                         !has_ScalarEnumerationTraits<T>::value
438                                      && !has_ScalarBitSetTraits<T>::value
439                                      && !has_ScalarTraits<T>::value
440                                      && !has_BlockScalarTraits<T>::value
441                                      && !has_MappingTraits<T>::value
442                                      && !has_SequenceTraits<T>::value
443                                      && !has_DocumentListTraits<T>::value >  {};
444
445template<typename T>
446struct validatedMappingTraits : public std::integral_constant<bool,
447                                       has_MappingTraits<T>::value
448                                    && has_MappingValidateTraits<T>::value> {};
449
450template<typename T>
451struct unvalidatedMappingTraits : public std::integral_constant<bool,
452                                        has_MappingTraits<T>::value
453                                    && !has_MappingValidateTraits<T>::value> {};
454// Base class for Input and Output.
455class IO {
456public:
457
458  IO(void *Ctxt=nullptr);
459  virtual ~IO();
460
461  virtual bool outputting() = 0;
462
463  virtual unsigned beginSequence() = 0;
464  virtual bool preflightElement(unsigned, void *&) = 0;
465  virtual void postflightElement(void*) = 0;
466  virtual void endSequence() = 0;
467  virtual bool canElideEmptySequence() = 0;
468
469  virtual unsigned beginFlowSequence() = 0;
470  virtual bool preflightFlowElement(unsigned, void *&) = 0;
471  virtual void postflightFlowElement(void*) = 0;
472  virtual void endFlowSequence() = 0;
473
474  virtual bool mapTag(StringRef Tag, bool Default=false) = 0;
475  virtual void beginMapping() = 0;
476  virtual void endMapping() = 0;
477  virtual bool preflightKey(const char*, bool, bool, bool &, void *&) = 0;
478  virtual void postflightKey(void*) = 0;
479
480  virtual void beginFlowMapping() = 0;
481  virtual void endFlowMapping() = 0;
482
483  virtual void beginEnumScalar() = 0;
484  virtual bool matchEnumScalar(const char*, bool) = 0;
485  virtual bool matchEnumFallback() = 0;
486  virtual void endEnumScalar() = 0;
487
488  virtual bool beginBitSetScalar(bool &) = 0;
489  virtual bool bitSetMatch(const char*, bool) = 0;
490  virtual void endBitSetScalar() = 0;
491
492  virtual void scalarString(StringRef &, bool) = 0;
493  virtual void blockScalarString(StringRef &) = 0;
494
495  virtual void setError(const Twine &) = 0;
496
497  template <typename T>
498  void enumCase(T &Val, const char* Str, const T ConstVal) {
499    if ( matchEnumScalar(Str, outputting() && Val == ConstVal) ) {
500      Val = ConstVal;
501    }
502  }
503
504  // allow anonymous enum values to be used with LLVM_YAML_STRONG_TYPEDEF
505  template <typename T>
506  void enumCase(T &Val, const char* Str, const uint32_t ConstVal) {
507    if ( matchEnumScalar(Str, outputting() && Val == static_cast<T>(ConstVal)) ) {
508      Val = ConstVal;
509    }
510  }
511
512  template <typename FBT, typename T>
513  void enumFallback(T &Val) {
514    if (matchEnumFallback()) {
515      // FIXME: Force integral conversion to allow strong typedefs to convert.
516      FBT Res = static_cast<typename FBT::BaseType>(Val);
517      yamlize(*this, Res, true);
518      Val = static_cast<T>(static_cast<typename FBT::BaseType>(Res));
519    }
520  }
521
522  template <typename T>
523  void bitSetCase(T &Val, const char* Str, const T ConstVal) {
524    if ( bitSetMatch(Str, outputting() && (Val & ConstVal) == ConstVal) ) {
525      Val = Val | ConstVal;
526    }
527  }
528
529  // allow anonymous enum values to be used with LLVM_YAML_STRONG_TYPEDEF
530  template <typename T>
531  void bitSetCase(T &Val, const char* Str, const uint32_t ConstVal) {
532    if ( bitSetMatch(Str, outputting() && (Val & ConstVal) == ConstVal) ) {
533      Val = Val | ConstVal;
534    }
535  }
536
537  template <typename T>
538  void maskedBitSetCase(T &Val, const char *Str, T ConstVal, T Mask) {
539    if (bitSetMatch(Str, outputting() && (Val & Mask) == ConstVal))
540      Val = Val | ConstVal;
541  }
542
543  template <typename T>
544  void maskedBitSetCase(T &Val, const char *Str, uint32_t ConstVal,
545                        uint32_t Mask) {
546    if (bitSetMatch(Str, outputting() && (Val & Mask) == ConstVal))
547      Val = Val | ConstVal;
548  }
549
550  void *getContext();
551  void setContext(void *);
552
553  template <typename T>
554  void mapRequired(const char* Key, T& Val) {
555    this->processKey(Key, Val, true);
556  }
557
558  template <typename T>
559  typename std::enable_if<has_SequenceTraits<T>::value,void>::type
560  mapOptional(const char* Key, T& Val) {
561    // omit key/value instead of outputting empty sequence
562    if ( this->canElideEmptySequence() && !(Val.begin() != Val.end()) )
563      return;
564    this->processKey(Key, Val, false);
565  }
566
567  template <typename T>
568  void mapOptional(const char* Key, Optional<T> &Val) {
569    processKeyWithDefault(Key, Val, Optional<T>(), /*Required=*/false);
570  }
571
572  template <typename T>
573  typename std::enable_if<!has_SequenceTraits<T>::value,void>::type
574  mapOptional(const char* Key, T& Val) {
575    this->processKey(Key, Val, false);
576  }
577
578  template <typename T>
579  void mapOptional(const char* Key, T& Val, const T& Default) {
580    this->processKeyWithDefault(Key, Val, Default, false);
581  }
582
583private:
584  template <typename T>
585  void processKeyWithDefault(const char *Key, Optional<T> &Val,
586                             const Optional<T> &DefaultValue, bool Required) {
587    assert(DefaultValue.hasValue() == false &&
588           "Optional<T> shouldn't have a value!");
589    void *SaveInfo;
590    bool UseDefault;
591    const bool sameAsDefault = outputting() && !Val.hasValue();
592    if (!outputting() && !Val.hasValue())
593      Val = T();
594    if (this->preflightKey(Key, Required, sameAsDefault, UseDefault,
595                           SaveInfo)) {
596      yamlize(*this, Val.getValue(), Required);
597      this->postflightKey(SaveInfo);
598    } else {
599      if (UseDefault)
600        Val = DefaultValue;
601    }
602  }
603
604  template <typename T>
605  void processKeyWithDefault(const char *Key, T &Val, const T& DefaultValue,
606                                                                bool Required) {
607    void *SaveInfo;
608    bool UseDefault;
609    const bool sameAsDefault = outputting() && Val == DefaultValue;
610    if ( this->preflightKey(Key, Required, sameAsDefault, UseDefault,
611                                                                  SaveInfo) ) {
612      yamlize(*this, Val, Required);
613      this->postflightKey(SaveInfo);
614    }
615    else {
616      if ( UseDefault )
617        Val = DefaultValue;
618    }
619  }
620
621  template <typename T>
622  void processKey(const char *Key, T &Val, bool Required) {
623    void *SaveInfo;
624    bool UseDefault;
625    if ( this->preflightKey(Key, Required, false, UseDefault, SaveInfo) ) {
626      yamlize(*this, Val, Required);
627      this->postflightKey(SaveInfo);
628    }
629  }
630
631private:
632  void  *Ctxt;
633};
634
635template<typename T>
636typename std::enable_if<has_ScalarEnumerationTraits<T>::value,void>::type
637yamlize(IO &io, T &Val, bool) {
638  io.beginEnumScalar();
639  ScalarEnumerationTraits<T>::enumeration(io, Val);
640  io.endEnumScalar();
641}
642
643template<typename T>
644typename std::enable_if<has_ScalarBitSetTraits<T>::value,void>::type
645yamlize(IO &io, T &Val, bool) {
646  bool DoClear;
647  if ( io.beginBitSetScalar(DoClear) ) {
648    if ( DoClear )
649      Val = static_cast<T>(0);
650    ScalarBitSetTraits<T>::bitset(io, Val);
651    io.endBitSetScalar();
652  }
653}
654
655template<typename T>
656typename std::enable_if<has_ScalarTraits<T>::value,void>::type
657yamlize(IO &io, T &Val, bool) {
658  if ( io.outputting() ) {
659    std::string Storage;
660    llvm::raw_string_ostream Buffer(Storage);
661    ScalarTraits<T>::output(Val, io.getContext(), Buffer);
662    StringRef Str = Buffer.str();
663    io.scalarString(Str, ScalarTraits<T>::mustQuote(Str));
664  }
665  else {
666    StringRef Str;
667    io.scalarString(Str, ScalarTraits<T>::mustQuote(Str));
668    StringRef Result = ScalarTraits<T>::input(Str, io.getContext(), Val);
669    if ( !Result.empty() ) {
670      io.setError(llvm::Twine(Result));
671    }
672  }
673}
674
675template <typename T>
676typename std::enable_if<has_BlockScalarTraits<T>::value, void>::type
677yamlize(IO &YamlIO, T &Val, bool) {
678  if (YamlIO.outputting()) {
679    std::string Storage;
680    llvm::raw_string_ostream Buffer(Storage);
681    BlockScalarTraits<T>::output(Val, YamlIO.getContext(), Buffer);
682    StringRef Str = Buffer.str();
683    YamlIO.blockScalarString(Str);
684  } else {
685    StringRef Str;
686    YamlIO.blockScalarString(Str);
687    StringRef Result =
688        BlockScalarTraits<T>::input(Str, YamlIO.getContext(), Val);
689    if (!Result.empty())
690      YamlIO.setError(llvm::Twine(Result));
691  }
692}
693
694template<typename T>
695typename std::enable_if<validatedMappingTraits<T>::value, void>::type
696yamlize(IO &io, T &Val, bool) {
697  if (has_FlowTraits<MappingTraits<T>>::value)
698    io.beginFlowMapping();
699  else
700    io.beginMapping();
701  if (io.outputting()) {
702    StringRef Err = MappingTraits<T>::validate(io, Val);
703    if (!Err.empty()) {
704      llvm::errs() << Err << "\n";
705      assert(Err.empty() && "invalid struct trying to be written as yaml");
706    }
707  }
708  MappingTraits<T>::mapping(io, Val);
709  if (!io.outputting()) {
710    StringRef Err = MappingTraits<T>::validate(io, Val);
711    if (!Err.empty())
712      io.setError(Err);
713  }
714  if (has_FlowTraits<MappingTraits<T>>::value)
715    io.endFlowMapping();
716  else
717    io.endMapping();
718}
719
720template<typename T>
721typename std::enable_if<unvalidatedMappingTraits<T>::value, void>::type
722yamlize(IO &io, T &Val, bool) {
723  if (has_FlowTraits<MappingTraits<T>>::value) {
724    io.beginFlowMapping();
725    MappingTraits<T>::mapping(io, Val);
726    io.endFlowMapping();
727  } else {
728    io.beginMapping();
729    MappingTraits<T>::mapping(io, Val);
730    io.endMapping();
731  }
732}
733
734template<typename T>
735typename std::enable_if<missingTraits<T>::value, void>::type
736yamlize(IO &io, T &Val, bool) {
737  char missing_yaml_trait_for_type[sizeof(MissingTrait<T>)];
738}
739
740template<typename T>
741typename std::enable_if<has_SequenceTraits<T>::value,void>::type
742yamlize(IO &io, T &Seq, bool) {
743  if ( has_FlowTraits< SequenceTraits<T> >::value ) {
744    unsigned incnt = io.beginFlowSequence();
745    unsigned count = io.outputting() ? SequenceTraits<T>::size(io, Seq) : incnt;
746    for(unsigned i=0; i < count; ++i) {
747      void *SaveInfo;
748      if ( io.preflightFlowElement(i, SaveInfo) ) {
749        yamlize(io, SequenceTraits<T>::element(io, Seq, i), true);
750        io.postflightFlowElement(SaveInfo);
751      }
752    }
753    io.endFlowSequence();
754  }
755  else {
756    unsigned incnt = io.beginSequence();
757    unsigned count = io.outputting() ? SequenceTraits<T>::size(io, Seq) : incnt;
758    for(unsigned i=0; i < count; ++i) {
759      void *SaveInfo;
760      if ( io.preflightElement(i, SaveInfo) ) {
761        yamlize(io, SequenceTraits<T>::element(io, Seq, i), true);
762        io.postflightElement(SaveInfo);
763      }
764    }
765    io.endSequence();
766  }
767}
768
769template<>
770struct ScalarTraits<bool> {
771  static void output(const bool &, void*, llvm::raw_ostream &);
772  static StringRef input(StringRef, void*, bool &);
773  static bool mustQuote(StringRef) { return false; }
774};
775
776template<>
777struct ScalarTraits<StringRef> {
778  static void output(const StringRef &, void*, llvm::raw_ostream &);
779  static StringRef input(StringRef, void*, StringRef &);
780  static bool mustQuote(StringRef S) { return needsQuotes(S); }
781};
782
783template<>
784struct ScalarTraits<std::string> {
785  static void output(const std::string &, void*, llvm::raw_ostream &);
786  static StringRef input(StringRef, void*, std::string &);
787  static bool mustQuote(StringRef S) { return needsQuotes(S); }
788};
789
790template<>
791struct ScalarTraits<uint8_t> {
792  static void output(const uint8_t &, void*, llvm::raw_ostream &);
793  static StringRef input(StringRef, void*, uint8_t &);
794  static bool mustQuote(StringRef) { return false; }
795};
796
797template<>
798struct ScalarTraits<uint16_t> {
799  static void output(const uint16_t &, void*, llvm::raw_ostream &);
800  static StringRef input(StringRef, void*, uint16_t &);
801  static bool mustQuote(StringRef) { return false; }
802};
803
804template<>
805struct ScalarTraits<uint32_t> {
806  static void output(const uint32_t &, void*, llvm::raw_ostream &);
807  static StringRef input(StringRef, void*, uint32_t &);
808  static bool mustQuote(StringRef) { return false; }
809};
810
811template<>
812struct ScalarTraits<uint64_t> {
813  static void output(const uint64_t &, void*, llvm::raw_ostream &);
814  static StringRef input(StringRef, void*, uint64_t &);
815  static bool mustQuote(StringRef) { return false; }
816};
817
818template<>
819struct ScalarTraits<int8_t> {
820  static void output(const int8_t &, void*, llvm::raw_ostream &);
821  static StringRef input(StringRef, void*, int8_t &);
822  static bool mustQuote(StringRef) { return false; }
823};
824
825template<>
826struct ScalarTraits<int16_t> {
827  static void output(const int16_t &, void*, llvm::raw_ostream &);
828  static StringRef input(StringRef, void*, int16_t &);
829  static bool mustQuote(StringRef) { return false; }
830};
831
832template<>
833struct ScalarTraits<int32_t> {
834  static void output(const int32_t &, void*, llvm::raw_ostream &);
835  static StringRef input(StringRef, void*, int32_t &);
836  static bool mustQuote(StringRef) { return false; }
837};
838
839template<>
840struct ScalarTraits<int64_t> {
841  static void output(const int64_t &, void*, llvm::raw_ostream &);
842  static StringRef input(StringRef, void*, int64_t &);
843  static bool mustQuote(StringRef) { return false; }
844};
845
846template<>
847struct ScalarTraits<float> {
848  static void output(const float &, void*, llvm::raw_ostream &);
849  static StringRef input(StringRef, void*, float &);
850  static bool mustQuote(StringRef) { return false; }
851};
852
853template<>
854struct ScalarTraits<double> {
855  static void output(const double &, void*, llvm::raw_ostream &);
856  static StringRef input(StringRef, void*, double &);
857  static bool mustQuote(StringRef) { return false; }
858};
859
860// For endian types, we just use the existing ScalarTraits for the underlying
861// type.  This way endian aware types are supported whenever a ScalarTraits
862// is defined for the underlying type.
863template <typename value_type, support::endianness endian, size_t alignment>
864struct ScalarTraits<support::detail::packed_endian_specific_integral<
865    value_type, endian, alignment>> {
866  typedef support::detail::packed_endian_specific_integral<value_type, endian,
867                                                           alignment>
868      endian_type;
869
870  static void output(const endian_type &E, void *Ctx,
871                     llvm::raw_ostream &Stream) {
872    ScalarTraits<value_type>::output(static_cast<value_type>(E), Ctx, Stream);
873  }
874  static StringRef input(StringRef Str, void *Ctx, endian_type &E) {
875    value_type V;
876    auto R = ScalarTraits<value_type>::input(Str, Ctx, V);
877    E = static_cast<endian_type>(V);
878    return R;
879  }
880
881  static bool mustQuote(StringRef Str) {
882    return ScalarTraits<value_type>::mustQuote(Str);
883  }
884};
885
886// Utility for use within MappingTraits<>::mapping() method
887// to [de]normalize an object for use with YAML conversion.
888template <typename TNorm, typename TFinal>
889struct MappingNormalization {
890  MappingNormalization(IO &i_o, TFinal &Obj)
891      : io(i_o), BufPtr(nullptr), Result(Obj) {
892    if ( io.outputting() ) {
893      BufPtr = new (&Buffer) TNorm(io, Obj);
894    }
895    else {
896      BufPtr = new (&Buffer) TNorm(io);
897    }
898  }
899
900  ~MappingNormalization() {
901    if ( ! io.outputting() ) {
902      Result = BufPtr->denormalize(io);
903    }
904    BufPtr->~TNorm();
905  }
906
907  TNorm* operator->() { return BufPtr; }
908
909private:
910  typedef llvm::AlignedCharArrayUnion<TNorm> Storage;
911
912  Storage       Buffer;
913  IO           &io;
914  TNorm        *BufPtr;
915  TFinal       &Result;
916};
917
918// Utility for use within MappingTraits<>::mapping() method
919// to [de]normalize an object for use with YAML conversion.
920template <typename TNorm, typename TFinal>
921struct MappingNormalizationHeap {
922  MappingNormalizationHeap(IO &i_o, TFinal &Obj,
923                           llvm::BumpPtrAllocator *allocator)
924    : io(i_o), BufPtr(nullptr), Result(Obj) {
925    if ( io.outputting() ) {
926      BufPtr = new (&Buffer) TNorm(io, Obj);
927    }
928    else if (allocator) {
929      BufPtr = allocator->Allocate<TNorm>();
930      new (BufPtr) TNorm(io);
931    } else {
932      BufPtr = new TNorm(io);
933    }
934  }
935
936  ~MappingNormalizationHeap() {
937    if ( io.outputting() ) {
938      BufPtr->~TNorm();
939    }
940    else {
941      Result = BufPtr->denormalize(io);
942    }
943  }
944
945  TNorm* operator->() { return BufPtr; }
946
947private:
948  typedef llvm::AlignedCharArrayUnion<TNorm> Storage;
949
950  Storage       Buffer;
951  IO           &io;
952  TNorm        *BufPtr;
953  TFinal       &Result;
954};
955
956///
957/// The Input class is used to parse a yaml document into in-memory structs
958/// and vectors.
959///
960/// It works by using YAMLParser to do a syntax parse of the entire yaml
961/// document, then the Input class builds a graph of HNodes which wraps
962/// each yaml Node.  The extra layer is buffering.  The low level yaml
963/// parser only lets you look at each node once.  The buffering layer lets
964/// you search and interate multiple times.  This is necessary because
965/// the mapRequired() method calls may not be in the same order
966/// as the keys in the document.
967///
968class Input : public IO {
969public:
970  // Construct a yaml Input object from a StringRef and optional
971  // user-data. The DiagHandler can be specified to provide
972  // alternative error reporting.
973  Input(StringRef InputContent,
974        void *Ctxt = nullptr,
975        SourceMgr::DiagHandlerTy DiagHandler = nullptr,
976        void *DiagHandlerCtxt = nullptr);
977  ~Input() override;
978
979  // Check if there was an syntax or semantic error during parsing.
980  std::error_code error();
981
982private:
983  bool outputting() override;
984  bool mapTag(StringRef, bool) override;
985  void beginMapping() override;
986  void endMapping() override;
987  bool preflightKey(const char *, bool, bool, bool &, void *&) override;
988  void postflightKey(void *) override;
989  void beginFlowMapping() override;
990  void endFlowMapping() override;
991  unsigned beginSequence() override;
992  void endSequence() override;
993  bool preflightElement(unsigned index, void *&) override;
994  void postflightElement(void *) override;
995  unsigned beginFlowSequence() override;
996  bool preflightFlowElement(unsigned , void *&) override;
997  void postflightFlowElement(void *) override;
998  void endFlowSequence() override;
999  void beginEnumScalar() override;
1000  bool matchEnumScalar(const char*, bool) override;
1001  bool matchEnumFallback() override;
1002  void endEnumScalar() override;
1003  bool beginBitSetScalar(bool &) override;
1004  bool bitSetMatch(const char *, bool ) override;
1005  void endBitSetScalar() override;
1006  void scalarString(StringRef &, bool) override;
1007  void blockScalarString(StringRef &) override;
1008  void setError(const Twine &message) override;
1009  bool canElideEmptySequence() override;
1010
1011  class HNode {
1012    virtual void anchor();
1013  public:
1014    HNode(Node *n) : _node(n) { }
1015    virtual ~HNode() { }
1016    static inline bool classof(const HNode *) { return true; }
1017
1018    Node *_node;
1019  };
1020
1021  class EmptyHNode : public HNode {
1022    void anchor() override;
1023  public:
1024    EmptyHNode(Node *n) : HNode(n) { }
1025    static inline bool classof(const HNode *n) {
1026      return NullNode::classof(n->_node);
1027    }
1028    static inline bool classof(const EmptyHNode *) { return true; }
1029  };
1030
1031  class ScalarHNode : public HNode {
1032    void anchor() override;
1033  public:
1034    ScalarHNode(Node *n, StringRef s) : HNode(n), _value(s) { }
1035
1036    StringRef value() const { return _value; }
1037
1038    static inline bool classof(const HNode *n) {
1039      return ScalarNode::classof(n->_node) ||
1040             BlockScalarNode::classof(n->_node);
1041    }
1042    static inline bool classof(const ScalarHNode *) { return true; }
1043  protected:
1044    StringRef _value;
1045  };
1046
1047  class MapHNode : public HNode {
1048    void anchor() override;
1049
1050  public:
1051    MapHNode(Node *n) : HNode(n) { }
1052
1053    static inline bool classof(const HNode *n) {
1054      return MappingNode::classof(n->_node);
1055    }
1056    static inline bool classof(const MapHNode *) { return true; }
1057
1058    typedef llvm::StringMap<std::unique_ptr<HNode>> NameToNode;
1059
1060    bool isValidKey(StringRef key);
1061
1062    NameToNode                        Mapping;
1063    llvm::SmallVector<const char*, 6> ValidKeys;
1064  };
1065
1066  class SequenceHNode : public HNode {
1067    void anchor() override;
1068
1069  public:
1070    SequenceHNode(Node *n) : HNode(n) { }
1071
1072    static inline bool classof(const HNode *n) {
1073      return SequenceNode::classof(n->_node);
1074    }
1075    static inline bool classof(const SequenceHNode *) { return true; }
1076
1077    std::vector<std::unique_ptr<HNode>> Entries;
1078  };
1079
1080  std::unique_ptr<Input::HNode> createHNodes(Node *node);
1081  void setError(HNode *hnode, const Twine &message);
1082  void setError(Node *node, const Twine &message);
1083
1084public:
1085  // These are only used by operator>>. They could be private
1086  // if those templated things could be made friends.
1087  bool setCurrentDocument();
1088  bool nextDocument();
1089
1090  /// Returns the current node that's being parsed by the YAML Parser.
1091  const Node *getCurrentNode() const;
1092
1093private:
1094  llvm::SourceMgr                     SrcMgr; // must be before Strm
1095  std::unique_ptr<llvm::yaml::Stream> Strm;
1096  std::unique_ptr<HNode>              TopNode;
1097  std::error_code                     EC;
1098  llvm::BumpPtrAllocator              StringAllocator;
1099  llvm::yaml::document_iterator       DocIterator;
1100  std::vector<bool>                   BitValuesUsed;
1101  HNode                              *CurrentNode;
1102  bool                                ScalarMatchFound;
1103};
1104
1105///
1106/// The Output class is used to generate a yaml document from in-memory structs
1107/// and vectors.
1108///
1109class Output : public IO {
1110public:
1111  Output(llvm::raw_ostream &, void *Ctxt = nullptr, int WrapColumn = 70);
1112  ~Output() override;
1113
1114  bool outputting() override;
1115  bool mapTag(StringRef, bool) override;
1116  void beginMapping() override;
1117  void endMapping() override;
1118  bool preflightKey(const char *key, bool, bool, bool &, void *&) override;
1119  void postflightKey(void *) override;
1120  void beginFlowMapping() override;
1121  void endFlowMapping() override;
1122  unsigned beginSequence() override;
1123  void endSequence() override;
1124  bool preflightElement(unsigned, void *&) override;
1125  void postflightElement(void *) override;
1126  unsigned beginFlowSequence() override;
1127  bool preflightFlowElement(unsigned, void *&) override;
1128  void postflightFlowElement(void *) override;
1129  void endFlowSequence() override;
1130  void beginEnumScalar() override;
1131  bool matchEnumScalar(const char*, bool) override;
1132  bool matchEnumFallback() override;
1133  void endEnumScalar() override;
1134  bool beginBitSetScalar(bool &) override;
1135  bool bitSetMatch(const char *, bool ) override;
1136  void endBitSetScalar() override;
1137  void scalarString(StringRef &, bool) override;
1138  void blockScalarString(StringRef &) override;
1139  void setError(const Twine &message) override;
1140  bool canElideEmptySequence() override;
1141public:
1142  // These are only used by operator<<. They could be private
1143  // if that templated operator could be made a friend.
1144  void beginDocuments();
1145  bool preflightDocument(unsigned);
1146  void postflightDocument();
1147  void endDocuments();
1148
1149private:
1150  void output(StringRef s);
1151  void outputUpToEndOfLine(StringRef s);
1152  void newLineCheck();
1153  void outputNewLine();
1154  void paddedKey(StringRef key);
1155  void flowKey(StringRef Key);
1156
1157  enum InState {
1158    inSeq,
1159    inFlowSeq,
1160    inMapFirstKey,
1161    inMapOtherKey,
1162    inFlowMapFirstKey,
1163    inFlowMapOtherKey
1164  };
1165
1166  llvm::raw_ostream       &Out;
1167  int                      WrapColumn;
1168  SmallVector<InState, 8>  StateStack;
1169  int                      Column;
1170  int                      ColumnAtFlowStart;
1171  int                      ColumnAtMapFlowStart;
1172  bool                     NeedBitValueComma;
1173  bool                     NeedFlowSequenceComma;
1174  bool                     EnumerationMatchFound;
1175  bool                     NeedsNewLine;
1176};
1177
1178/// YAML I/O does conversion based on types. But often native data types
1179/// are just a typedef of built in intergral types (e.g. int).  But the C++
1180/// type matching system sees through the typedef and all the typedefed types
1181/// look like a built in type. This will cause the generic YAML I/O conversion
1182/// to be used. To provide better control over the YAML conversion, you can
1183/// use this macro instead of typedef.  It will create a class with one field
1184/// and automatic conversion operators to and from the base type.
1185/// Based on BOOST_STRONG_TYPEDEF
1186#define LLVM_YAML_STRONG_TYPEDEF(_base, _type)                                 \
1187    struct _type {                                                             \
1188        _type() { }                                                            \
1189        _type(const _base v) : value(v) { }                                    \
1190        _type(const _type &v) : value(v.value) {}                              \
1191        _type &operator=(const _type &rhs) { value = rhs.value; return *this; }\
1192        _type &operator=(const _base &rhs) { value = rhs; return *this; }      \
1193        operator const _base & () const { return value; }                      \
1194        bool operator==(const _type &rhs) const { return value == rhs.value; } \
1195        bool operator==(const _base &rhs) const { return value == rhs; }       \
1196        bool operator<(const _type &rhs) const { return value < rhs.value; }   \
1197        _base value;                                                           \
1198        typedef _base BaseType;                                                \
1199    };
1200
1201///
1202/// Use these types instead of uintXX_t in any mapping to have
1203/// its yaml output formatted as hexadecimal.
1204///
1205LLVM_YAML_STRONG_TYPEDEF(uint8_t, Hex8)
1206LLVM_YAML_STRONG_TYPEDEF(uint16_t, Hex16)
1207LLVM_YAML_STRONG_TYPEDEF(uint32_t, Hex32)
1208LLVM_YAML_STRONG_TYPEDEF(uint64_t, Hex64)
1209
1210template<>
1211struct ScalarTraits<Hex8> {
1212  static void output(const Hex8 &, void*, llvm::raw_ostream &);
1213  static StringRef input(StringRef, void*, Hex8 &);
1214  static bool mustQuote(StringRef) { return false; }
1215};
1216
1217template<>
1218struct ScalarTraits<Hex16> {
1219  static void output(const Hex16 &, void*, llvm::raw_ostream &);
1220  static StringRef input(StringRef, void*, Hex16 &);
1221  static bool mustQuote(StringRef) { return false; }
1222};
1223
1224template<>
1225struct ScalarTraits<Hex32> {
1226  static void output(const Hex32 &, void*, llvm::raw_ostream &);
1227  static StringRef input(StringRef, void*, Hex32 &);
1228  static bool mustQuote(StringRef) { return false; }
1229};
1230
1231template<>
1232struct ScalarTraits<Hex64> {
1233  static void output(const Hex64 &, void*, llvm::raw_ostream &);
1234  static StringRef input(StringRef, void*, Hex64 &);
1235  static bool mustQuote(StringRef) { return false; }
1236};
1237
1238// Define non-member operator>> so that Input can stream in a document list.
1239template <typename T>
1240inline
1241typename std::enable_if<has_DocumentListTraits<T>::value, Input &>::type
1242operator>>(Input &yin, T &docList) {
1243  int i = 0;
1244  while ( yin.setCurrentDocument() ) {
1245    yamlize(yin, DocumentListTraits<T>::element(yin, docList, i), true);
1246    if ( yin.error() )
1247      return yin;
1248    yin.nextDocument();
1249    ++i;
1250  }
1251  return yin;
1252}
1253
1254// Define non-member operator>> so that Input can stream in a map as a document.
1255template <typename T>
1256inline
1257typename std::enable_if<has_MappingTraits<T>::value, Input &>::type
1258operator>>(Input &yin, T &docMap) {
1259  yin.setCurrentDocument();
1260  yamlize(yin, docMap, true);
1261  return yin;
1262}
1263
1264// Define non-member operator>> so that Input can stream in a sequence as
1265// a document.
1266template <typename T>
1267inline
1268typename std::enable_if<has_SequenceTraits<T>::value, Input &>::type
1269operator>>(Input &yin, T &docSeq) {
1270  if (yin.setCurrentDocument())
1271    yamlize(yin, docSeq, true);
1272  return yin;
1273}
1274
1275// Define non-member operator>> so that Input can stream in a block scalar.
1276template <typename T>
1277inline
1278typename std::enable_if<has_BlockScalarTraits<T>::value, Input &>::type
1279operator>>(Input &In, T &Val) {
1280  if (In.setCurrentDocument())
1281    yamlize(In, Val, true);
1282  return In;
1283}
1284
1285// Provide better error message about types missing a trait specialization
1286template <typename T>
1287inline
1288typename std::enable_if<missingTraits<T>::value, Input &>::type
1289operator>>(Input &yin, T &docSeq) {
1290  char missing_yaml_trait_for_type[sizeof(MissingTrait<T>)];
1291  return yin;
1292}
1293
1294// Define non-member operator<< so that Output can stream out document list.
1295template <typename T>
1296inline
1297typename std::enable_if<has_DocumentListTraits<T>::value, Output &>::type
1298operator<<(Output &yout, T &docList) {
1299  yout.beginDocuments();
1300  const size_t count = DocumentListTraits<T>::size(yout, docList);
1301  for(size_t i=0; i < count; ++i) {
1302    if ( yout.preflightDocument(i) ) {
1303      yamlize(yout, DocumentListTraits<T>::element(yout, docList, i), true);
1304      yout.postflightDocument();
1305    }
1306  }
1307  yout.endDocuments();
1308  return yout;
1309}
1310
1311// Define non-member operator<< so that Output can stream out a map.
1312template <typename T>
1313inline
1314typename std::enable_if<has_MappingTraits<T>::value, Output &>::type
1315operator<<(Output &yout, T &map) {
1316  yout.beginDocuments();
1317  if ( yout.preflightDocument(0) ) {
1318    yamlize(yout, map, true);
1319    yout.postflightDocument();
1320  }
1321  yout.endDocuments();
1322  return yout;
1323}
1324
1325// Define non-member operator<< so that Output can stream out a sequence.
1326template <typename T>
1327inline
1328typename std::enable_if<has_SequenceTraits<T>::value, Output &>::type
1329operator<<(Output &yout, T &seq) {
1330  yout.beginDocuments();
1331  if ( yout.preflightDocument(0) ) {
1332    yamlize(yout, seq, true);
1333    yout.postflightDocument();
1334  }
1335  yout.endDocuments();
1336  return yout;
1337}
1338
1339// Define non-member operator<< so that Output can stream out a block scalar.
1340template <typename T>
1341inline
1342typename std::enable_if<has_BlockScalarTraits<T>::value, Output &>::type
1343operator<<(Output &Out, T &Val) {
1344  Out.beginDocuments();
1345  if (Out.preflightDocument(0)) {
1346    yamlize(Out, Val, true);
1347    Out.postflightDocument();
1348  }
1349  Out.endDocuments();
1350  return Out;
1351}
1352
1353// Provide better error message about types missing a trait specialization
1354template <typename T>
1355inline
1356typename std::enable_if<missingTraits<T>::value, Output &>::type
1357operator<<(Output &yout, T &seq) {
1358  char missing_yaml_trait_for_type[sizeof(MissingTrait<T>)];
1359  return yout;
1360}
1361
1362} // namespace yaml
1363} // namespace llvm
1364
1365/// Utility for declaring that a std::vector of a particular type
1366/// should be considered a YAML sequence.
1367#define LLVM_YAML_IS_SEQUENCE_VECTOR(_type)                                 \
1368  namespace llvm {                                                          \
1369  namespace yaml {                                                          \
1370    template<>                                                              \
1371    struct SequenceTraits< std::vector<_type> > {                           \
1372      static size_t size(IO &io, std::vector<_type> &seq) {                 \
1373        return seq.size();                                                  \
1374      }                                                                     \
1375      static _type& element(IO &io, std::vector<_type> &seq, size_t index) {\
1376        if ( index >= seq.size() )                                          \
1377          seq.resize(index+1);                                              \
1378        return seq[index];                                                  \
1379      }                                                                     \
1380    };                                                                      \
1381  }                                                                         \
1382  }
1383
1384/// Utility for declaring that a std::vector of a particular type
1385/// should be considered a YAML flow sequence.
1386#define LLVM_YAML_IS_FLOW_SEQUENCE_VECTOR(_type)                            \
1387  namespace llvm {                                                          \
1388  namespace yaml {                                                          \
1389    template<>                                                              \
1390    struct SequenceTraits< std::vector<_type> > {                           \
1391      static size_t size(IO &io, std::vector<_type> &seq) {                 \
1392        return seq.size();                                                  \
1393      }                                                                     \
1394      static _type& element(IO &io, std::vector<_type> &seq, size_t index) {\
1395        (void)flow; /* Remove this workaround after PR17897 is fixed */     \
1396        if ( index >= seq.size() )                                          \
1397          seq.resize(index+1);                                              \
1398        return seq[index];                                                  \
1399      }                                                                     \
1400      static const bool flow = true;                                        \
1401    };                                                                      \
1402  }                                                                         \
1403  }
1404
1405/// Utility for declaring that a std::vector of a particular type
1406/// should be considered a YAML document list.
1407#define LLVM_YAML_IS_DOCUMENT_LIST_VECTOR(_type)                            \
1408  namespace llvm {                                                          \
1409  namespace yaml {                                                          \
1410    template<>                                                              \
1411    struct DocumentListTraits< std::vector<_type> > {                       \
1412      static size_t size(IO &io, std::vector<_type> &seq) {                 \
1413        return seq.size();                                                  \
1414      }                                                                     \
1415      static _type& element(IO &io, std::vector<_type> &seq, size_t index) {\
1416        if ( index >= seq.size() )                                          \
1417          seq.resize(index+1);                                              \
1418        return seq[index];                                                  \
1419      }                                                                     \
1420    };                                                                      \
1421  }                                                                         \
1422  }
1423
1424#endif // LLVM_SUPPORT_YAMLTRAITS_H
1425