1 //===- Diagnostic.h - C Language Family Diagnostic Handling -----*- C++ -*-===//
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 /// Defines the Diagnostic-related interfaces.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_BASIC_DIAGNOSTIC_H
15 #define LLVM_CLANG_BASIC_DIAGNOSTIC_H
16 
17 #include "clang/Basic/DiagnosticIDs.h"
18 #include "clang/Basic/DiagnosticOptions.h"
19 #include "clang/Basic/SourceLocation.h"
20 #include "clang/Basic/Specifiers.h"
21 #include "llvm/ADT/ArrayRef.h"
22 #include "llvm/ADT/DenseMap.h"
23 #include "llvm/ADT/IntrusiveRefCntPtr.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/iterator_range.h"
27 #include "llvm/Support/Compiler.h"
28 #include "llvm/Support/Error.h"
29 #include <cassert>
30 #include <cstdint>
31 #include <limits>
32 #include <list>
33 #include <map>
34 #include <memory>
35 #include <string>
36 #include <type_traits>
37 #include <utility>
38 #include <vector>
39 
40 namespace clang {
41 
42 class DeclContext;
43 class DiagnosticBuilder;
44 class DiagnosticConsumer;
45 class IdentifierInfo;
46 class LangOptions;
47 class Preprocessor;
48 class SourceManager;
49 class StoredDiagnostic;
50 
51 namespace tok {
52 
53 enum TokenKind : unsigned short;
54 
55 } // namespace tok
56 
57 /// Annotates a diagnostic with some code that should be
58 /// inserted, removed, or replaced to fix the problem.
59 ///
60 /// This kind of hint should be used when we are certain that the
61 /// introduction, removal, or modification of a particular (small!)
62 /// amount of code will correct a compilation error. The compiler
63 /// should also provide full recovery from such errors, such that
64 /// suppressing the diagnostic output can still result in successful
65 /// compilation.
66 class FixItHint {
67 public:
68   /// Code that should be replaced to correct the error. Empty for an
69   /// insertion hint.
70   CharSourceRange RemoveRange;
71 
72   /// Code in the specific range that should be inserted in the insertion
73   /// location.
74   CharSourceRange InsertFromRange;
75 
76   /// The actual code to insert at the insertion location, as a
77   /// string.
78   std::string CodeToInsert;
79 
80   bool BeforePreviousInsertions = false;
81 
82   /// Empty code modification hint, indicating that no code
83   /// modification is known.
84   FixItHint() = default;
85 
86   bool isNull() const {
87     return !RemoveRange.isValid();
88   }
89 
90   /// Create a code modification hint that inserts the given
91   /// code string at a specific location.
92   static FixItHint CreateInsertion(SourceLocation InsertionLoc,
93                                    StringRef Code,
94                                    bool BeforePreviousInsertions = false) {
95     FixItHint Hint;
96     Hint.RemoveRange =
97       CharSourceRange::getCharRange(InsertionLoc, InsertionLoc);
98     Hint.CodeToInsert = Code;
99     Hint.BeforePreviousInsertions = BeforePreviousInsertions;
100     return Hint;
101   }
102 
103   /// Create a code modification hint that inserts the given
104   /// code from \p FromRange at a specific location.
105   static FixItHint CreateInsertionFromRange(SourceLocation InsertionLoc,
106                                             CharSourceRange FromRange,
107                                         bool BeforePreviousInsertions = false) {
108     FixItHint Hint;
109     Hint.RemoveRange =
110       CharSourceRange::getCharRange(InsertionLoc, InsertionLoc);
111     Hint.InsertFromRange = FromRange;
112     Hint.BeforePreviousInsertions = BeforePreviousInsertions;
113     return Hint;
114   }
115 
116   /// Create a code modification hint that removes the given
117   /// source range.
118   static FixItHint CreateRemoval(CharSourceRange RemoveRange) {
119     FixItHint Hint;
120     Hint.RemoveRange = RemoveRange;
121     return Hint;
122   }
123   static FixItHint CreateRemoval(SourceRange RemoveRange) {
124     return CreateRemoval(CharSourceRange::getTokenRange(RemoveRange));
125   }
126 
127   /// Create a code modification hint that replaces the given
128   /// source range with the given code string.
129   static FixItHint CreateReplacement(CharSourceRange RemoveRange,
130                                      StringRef Code) {
131     FixItHint Hint;
132     Hint.RemoveRange = RemoveRange;
133     Hint.CodeToInsert = Code;
134     return Hint;
135   }
136 
137   static FixItHint CreateReplacement(SourceRange RemoveRange,
138                                      StringRef Code) {
139     return CreateReplacement(CharSourceRange::getTokenRange(RemoveRange), Code);
140   }
141 };
142 
143 /// Concrete class used by the front-end to report problems and issues.
144 ///
145 /// This massages the diagnostics (e.g. handling things like "report warnings
146 /// as errors" and passes them off to the DiagnosticConsumer for reporting to
147 /// the user. DiagnosticsEngine is tied to one translation unit and one
148 /// SourceManager.
149 class DiagnosticsEngine : public RefCountedBase<DiagnosticsEngine> {
150 public:
151   /// The level of the diagnostic, after it has been through mapping.
152   enum Level {
153     Ignored = DiagnosticIDs::Ignored,
154     Note = DiagnosticIDs::Note,
155     Remark = DiagnosticIDs::Remark,
156     Warning = DiagnosticIDs::Warning,
157     Error = DiagnosticIDs::Error,
158     Fatal = DiagnosticIDs::Fatal
159   };
160 
161   enum ArgumentKind {
162     /// std::string
163     ak_std_string,
164 
165     /// const char *
166     ak_c_string,
167 
168     /// int
169     ak_sint,
170 
171     /// unsigned
172     ak_uint,
173 
174     /// enum TokenKind : unsigned
175     ak_tokenkind,
176 
177     /// IdentifierInfo
178     ak_identifierinfo,
179 
180     /// address space
181     ak_addrspace,
182 
183     /// Qualifiers
184     ak_qual,
185 
186     /// QualType
187     ak_qualtype,
188 
189     /// DeclarationName
190     ak_declarationname,
191 
192     /// NamedDecl *
193     ak_nameddecl,
194 
195     /// NestedNameSpecifier *
196     ak_nestednamespec,
197 
198     /// DeclContext *
199     ak_declcontext,
200 
201     /// pair<QualType, QualType>
202     ak_qualtype_pair,
203 
204     /// Attr *
205     ak_attr
206   };
207 
208   /// Represents on argument value, which is a union discriminated
209   /// by ArgumentKind, with a value.
210   using ArgumentValue = std::pair<ArgumentKind, intptr_t>;
211 
212 private:
213   // Used by __extension__
214   unsigned char AllExtensionsSilenced = 0;
215 
216   // Treat fatal errors like errors.
217   bool FatalsAsError = false;
218 
219   // Suppress all diagnostics.
220   bool SuppressAllDiagnostics = false;
221 
222   // Elide common types of templates.
223   bool ElideType = true;
224 
225   // Print a tree when comparing templates.
226   bool PrintTemplateTree = false;
227 
228   // Color printing is enabled.
229   bool ShowColors = false;
230 
231   // Which overload candidates to show.
232   OverloadsShown ShowOverloads = Ovl_All;
233 
234   // Cap of # errors emitted, 0 -> no limit.
235   unsigned ErrorLimit = 0;
236 
237   // Cap on depth of template backtrace stack, 0 -> no limit.
238   unsigned TemplateBacktraceLimit = 0;
239 
240   // Cap on depth of constexpr evaluation backtrace stack, 0 -> no limit.
241   unsigned ConstexprBacktraceLimit = 0;
242 
243   IntrusiveRefCntPtr<DiagnosticIDs> Diags;
244   IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts;
245   DiagnosticConsumer *Client = nullptr;
246   std::unique_ptr<DiagnosticConsumer> Owner;
247   SourceManager *SourceMgr = nullptr;
248 
249   /// Mapping information for diagnostics.
250   ///
251   /// Mapping info is packed into four bits per diagnostic.  The low three
252   /// bits are the mapping (an instance of diag::Severity), or zero if unset.
253   /// The high bit is set when the mapping was established as a user mapping.
254   /// If the high bit is clear, then the low bits are set to the default
255   /// value, and should be mapped with -pedantic, -Werror, etc.
256   ///
257   /// A new DiagState is created and kept around when diagnostic pragmas modify
258   /// the state so that we know what is the diagnostic state at any given
259   /// source location.
260   class DiagState {
261     llvm::DenseMap<unsigned, DiagnosticMapping> DiagMap;
262 
263   public:
264     // "Global" configuration state that can actually vary between modules.
265 
266     // Ignore all warnings: -w
267     unsigned IgnoreAllWarnings : 1;
268 
269     // Enable all warnings.
270     unsigned EnableAllWarnings : 1;
271 
272     // Treat warnings like errors.
273     unsigned WarningsAsErrors : 1;
274 
275     // Treat errors like fatal errors.
276     unsigned ErrorsAsFatal : 1;
277 
278     // Suppress warnings in system headers.
279     unsigned SuppressSystemWarnings : 1;
280 
281     // Map extensions to warnings or errors?
282     diag::Severity ExtBehavior = diag::Severity::Ignored;
283 
284     DiagState()
285         : IgnoreAllWarnings(false), EnableAllWarnings(false),
286           WarningsAsErrors(false), ErrorsAsFatal(false),
287           SuppressSystemWarnings(false) {}
288 
289     using iterator = llvm::DenseMap<unsigned, DiagnosticMapping>::iterator;
290     using const_iterator =
291         llvm::DenseMap<unsigned, DiagnosticMapping>::const_iterator;
292 
293     void setMapping(diag::kind Diag, DiagnosticMapping Info) {
294       DiagMap[Diag] = Info;
295     }
296 
297     DiagnosticMapping lookupMapping(diag::kind Diag) const {
298       return DiagMap.lookup(Diag);
299     }
300 
301     DiagnosticMapping &getOrAddMapping(diag::kind Diag);
302 
303     const_iterator begin() const { return DiagMap.begin(); }
304     const_iterator end() const { return DiagMap.end(); }
305   };
306 
307   /// Keeps and automatically disposes all DiagStates that we create.
308   std::list<DiagState> DiagStates;
309 
310   /// A mapping from files to the diagnostic states for those files. Lazily
311   /// built on demand for files in which the diagnostic state has not changed.
312   class DiagStateMap {
313   public:
314     /// Add an initial diagnostic state.
315     void appendFirst(DiagState *State);
316 
317     /// Add a new latest state point.
318     void append(SourceManager &SrcMgr, SourceLocation Loc, DiagState *State);
319 
320     /// Look up the diagnostic state at a given source location.
321     DiagState *lookup(SourceManager &SrcMgr, SourceLocation Loc) const;
322 
323     /// Determine whether this map is empty.
324     bool empty() const { return Files.empty(); }
325 
326     /// Clear out this map.
327     void clear() {
328       Files.clear();
329       FirstDiagState = CurDiagState = nullptr;
330       CurDiagStateLoc = SourceLocation();
331     }
332 
333     /// Produce a debugging dump of the diagnostic state.
334     LLVM_DUMP_METHOD void dump(SourceManager &SrcMgr,
335                                StringRef DiagName = StringRef()) const;
336 
337     /// Grab the most-recently-added state point.
338     DiagState *getCurDiagState() const { return CurDiagState; }
339 
340     /// Get the location at which a diagnostic state was last added.
341     SourceLocation getCurDiagStateLoc() const { return CurDiagStateLoc; }
342 
343   private:
344     friend class ASTReader;
345     friend class ASTWriter;
346 
347     /// Represents a point in source where the diagnostic state was
348     /// modified because of a pragma.
349     ///
350     /// 'Loc' can be null if the point represents the diagnostic state
351     /// modifications done through the command-line.
352     struct DiagStatePoint {
353       DiagState *State;
354       unsigned Offset;
355 
356       DiagStatePoint(DiagState *State, unsigned Offset)
357           : State(State), Offset(Offset) {}
358     };
359 
360     /// Description of the diagnostic states and state transitions for a
361     /// particular FileID.
362     struct File {
363       /// The diagnostic state for the parent file. This is strictly redundant,
364       /// as looking up the DecomposedIncludedLoc for the FileID in the Files
365       /// map would give us this, but we cache it here for performance.
366       File *Parent = nullptr;
367 
368       /// The offset of this file within its parent.
369       unsigned ParentOffset = 0;
370 
371       /// Whether this file has any local (not imported from an AST file)
372       /// diagnostic state transitions.
373       bool HasLocalTransitions = false;
374 
375       /// The points within the file where the state changes. There will always
376       /// be at least one of these (the state on entry to the file).
377       llvm::SmallVector<DiagStatePoint, 4> StateTransitions;
378 
379       DiagState *lookup(unsigned Offset) const;
380     };
381 
382     /// The diagnostic states for each file.
383     mutable std::map<FileID, File> Files;
384 
385     /// The initial diagnostic state.
386     DiagState *FirstDiagState;
387 
388     /// The current diagnostic state.
389     DiagState *CurDiagState;
390 
391     /// The location at which the current diagnostic state was established.
392     SourceLocation CurDiagStateLoc;
393 
394     /// Get the diagnostic state information for a file.
395     File *getFile(SourceManager &SrcMgr, FileID ID) const;
396   };
397 
398   DiagStateMap DiagStatesByLoc;
399 
400   /// Keeps the DiagState that was active during each diagnostic 'push'
401   /// so we can get back at it when we 'pop'.
402   std::vector<DiagState *> DiagStateOnPushStack;
403 
404   DiagState *GetCurDiagState() const {
405     return DiagStatesByLoc.getCurDiagState();
406   }
407 
408   void PushDiagStatePoint(DiagState *State, SourceLocation L);
409 
410   /// Finds the DiagStatePoint that contains the diagnostic state of
411   /// the given source location.
412   DiagState *GetDiagStateForLoc(SourceLocation Loc) const {
413     return SourceMgr ? DiagStatesByLoc.lookup(*SourceMgr, Loc)
414                      : DiagStatesByLoc.getCurDiagState();
415   }
416 
417   /// Sticky flag set to \c true when an error is emitted.
418   bool ErrorOccurred;
419 
420   /// Sticky flag set to \c true when an "uncompilable error" occurs.
421   /// I.e. an error that was not upgraded from a warning by -Werror.
422   bool UncompilableErrorOccurred;
423 
424   /// Sticky flag set to \c true when a fatal error is emitted.
425   bool FatalErrorOccurred;
426 
427   /// Indicates that an unrecoverable error has occurred.
428   bool UnrecoverableErrorOccurred;
429 
430   /// Counts for DiagnosticErrorTrap to check whether an error occurred
431   /// during a parsing section, e.g. during parsing a function.
432   unsigned TrapNumErrorsOccurred;
433   unsigned TrapNumUnrecoverableErrorsOccurred;
434 
435   /// The level of the last diagnostic emitted.
436   ///
437   /// This is used to emit continuation diagnostics with the same level as the
438   /// diagnostic that they follow.
439   DiagnosticIDs::Level LastDiagLevel;
440 
441   /// Number of warnings reported
442   unsigned NumWarnings;
443 
444   /// Number of errors reported
445   unsigned NumErrors;
446 
447   /// A function pointer that converts an opaque diagnostic
448   /// argument to a strings.
449   ///
450   /// This takes the modifiers and argument that was present in the diagnostic.
451   ///
452   /// The PrevArgs array indicates the previous arguments formatted for this
453   /// diagnostic.  Implementations of this function can use this information to
454   /// avoid redundancy across arguments.
455   ///
456   /// This is a hack to avoid a layering violation between libbasic and libsema.
457   using ArgToStringFnTy = void (*)(
458       ArgumentKind Kind, intptr_t Val,
459       StringRef Modifier, StringRef Argument,
460       ArrayRef<ArgumentValue> PrevArgs,
461       SmallVectorImpl<char> &Output,
462       void *Cookie,
463       ArrayRef<intptr_t> QualTypeVals);
464 
465   void *ArgToStringCookie = nullptr;
466   ArgToStringFnTy ArgToStringFn;
467 
468   /// ID of the "delayed" diagnostic, which is a (typically
469   /// fatal) diagnostic that had to be delayed because it was found
470   /// while emitting another diagnostic.
471   unsigned DelayedDiagID;
472 
473   /// First string argument for the delayed diagnostic.
474   std::string DelayedDiagArg1;
475 
476   /// Second string argument for the delayed diagnostic.
477   std::string DelayedDiagArg2;
478 
479   /// Third string argument for the delayed diagnostic.
480   std::string DelayedDiagArg3;
481 
482   /// Optional flag value.
483   ///
484   /// Some flags accept values, for instance: -Wframe-larger-than=<value> and
485   /// -Rpass=<value>. The content of this string is emitted after the flag name
486   /// and '='.
487   std::string FlagValue;
488 
489 public:
490   explicit DiagnosticsEngine(IntrusiveRefCntPtr<DiagnosticIDs> Diags,
491                              IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts,
492                              DiagnosticConsumer *client = nullptr,
493                              bool ShouldOwnClient = true);
494   DiagnosticsEngine(const DiagnosticsEngine &) = delete;
495   DiagnosticsEngine &operator=(const DiagnosticsEngine &) = delete;
496   ~DiagnosticsEngine();
497 
498   LLVM_DUMP_METHOD void dump() const;
499   LLVM_DUMP_METHOD void dump(StringRef DiagName) const;
500 
501   const IntrusiveRefCntPtr<DiagnosticIDs> &getDiagnosticIDs() const {
502     return Diags;
503   }
504 
505   /// Retrieve the diagnostic options.
506   DiagnosticOptions &getDiagnosticOptions() const { return *DiagOpts; }
507 
508   using diag_mapping_range = llvm::iterator_range<DiagState::const_iterator>;
509 
510   /// Get the current set of diagnostic mappings.
511   diag_mapping_range getDiagnosticMappings() const {
512     const DiagState &DS = *GetCurDiagState();
513     return diag_mapping_range(DS.begin(), DS.end());
514   }
515 
516   DiagnosticConsumer *getClient() { return Client; }
517   const DiagnosticConsumer *getClient() const { return Client; }
518 
519   /// Determine whether this \c DiagnosticsEngine object own its client.
520   bool ownsClient() const { return Owner != nullptr; }
521 
522   /// Return the current diagnostic client along with ownership of that
523   /// client.
524   std::unique_ptr<DiagnosticConsumer> takeClient() { return std::move(Owner); }
525 
526   bool hasSourceManager() const { return SourceMgr != nullptr; }
527 
528   SourceManager &getSourceManager() const {
529     assert(SourceMgr && "SourceManager not set!");
530     return *SourceMgr;
531   }
532 
533   void setSourceManager(SourceManager *SrcMgr) {
534     assert(DiagStatesByLoc.empty() &&
535            "Leftover diag state from a different SourceManager.");
536     SourceMgr = SrcMgr;
537   }
538 
539   //===--------------------------------------------------------------------===//
540   //  DiagnosticsEngine characterization methods, used by a client to customize
541   //  how diagnostics are emitted.
542   //
543 
544   /// Copies the current DiagMappings and pushes the new copy
545   /// onto the top of the stack.
546   void pushMappings(SourceLocation Loc);
547 
548   /// Pops the current DiagMappings off the top of the stack,
549   /// causing the new top of the stack to be the active mappings.
550   ///
551   /// \returns \c true if the pop happens, \c false if there is only one
552   /// DiagMapping on the stack.
553   bool popMappings(SourceLocation Loc);
554 
555   /// Set the diagnostic client associated with this diagnostic object.
556   ///
557   /// \param ShouldOwnClient true if the diagnostic object should take
558   /// ownership of \c client.
559   void setClient(DiagnosticConsumer *client, bool ShouldOwnClient = true);
560 
561   /// Specify a limit for the number of errors we should
562   /// emit before giving up.
563   ///
564   /// Zero disables the limit.
565   void setErrorLimit(unsigned Limit) { ErrorLimit = Limit; }
566 
567   /// Specify the maximum number of template instantiation
568   /// notes to emit along with a given diagnostic.
569   void setTemplateBacktraceLimit(unsigned Limit) {
570     TemplateBacktraceLimit = Limit;
571   }
572 
573   /// Retrieve the maximum number of template instantiation
574   /// notes to emit along with a given diagnostic.
575   unsigned getTemplateBacktraceLimit() const {
576     return TemplateBacktraceLimit;
577   }
578 
579   /// Specify the maximum number of constexpr evaluation
580   /// notes to emit along with a given diagnostic.
581   void setConstexprBacktraceLimit(unsigned Limit) {
582     ConstexprBacktraceLimit = Limit;
583   }
584 
585   /// Retrieve the maximum number of constexpr evaluation
586   /// notes to emit along with a given diagnostic.
587   unsigned getConstexprBacktraceLimit() const {
588     return ConstexprBacktraceLimit;
589   }
590 
591   /// When set to true, any unmapped warnings are ignored.
592   ///
593   /// If this and WarningsAsErrors are both set, then this one wins.
594   void setIgnoreAllWarnings(bool Val) {
595     GetCurDiagState()->IgnoreAllWarnings = Val;
596   }
597   bool getIgnoreAllWarnings() const {
598     return GetCurDiagState()->IgnoreAllWarnings;
599   }
600 
601   /// When set to true, any unmapped ignored warnings are no longer
602   /// ignored.
603   ///
604   /// If this and IgnoreAllWarnings are both set, then that one wins.
605   void setEnableAllWarnings(bool Val) {
606     GetCurDiagState()->EnableAllWarnings = Val;
607   }
608   bool getEnableAllWarnings() const {
609     return GetCurDiagState()->EnableAllWarnings;
610   }
611 
612   /// When set to true, any warnings reported are issued as errors.
613   void setWarningsAsErrors(bool Val) {
614     GetCurDiagState()->WarningsAsErrors = Val;
615   }
616   bool getWarningsAsErrors() const {
617     return GetCurDiagState()->WarningsAsErrors;
618   }
619 
620   /// When set to true, any error reported is made a fatal error.
621   void setErrorsAsFatal(bool Val) { GetCurDiagState()->ErrorsAsFatal = Val; }
622   bool getErrorsAsFatal() const { return GetCurDiagState()->ErrorsAsFatal; }
623 
624   /// \brief When set to true, any fatal error reported is made an error.
625   ///
626   /// This setting takes precedence over the setErrorsAsFatal setting above.
627   void setFatalsAsError(bool Val) { FatalsAsError = Val; }
628   bool getFatalsAsError() const { return FatalsAsError; }
629 
630   /// When set to true mask warnings that come from system headers.
631   void setSuppressSystemWarnings(bool Val) {
632     GetCurDiagState()->SuppressSystemWarnings = Val;
633   }
634   bool getSuppressSystemWarnings() const {
635     return GetCurDiagState()->SuppressSystemWarnings;
636   }
637 
638   /// Suppress all diagnostics, to silence the front end when we
639   /// know that we don't want any more diagnostics to be passed along to the
640   /// client
641   void setSuppressAllDiagnostics(bool Val) { SuppressAllDiagnostics = Val; }
642   bool getSuppressAllDiagnostics() const { return SuppressAllDiagnostics; }
643 
644   /// Set type eliding, to skip outputting same types occurring in
645   /// template types.
646   void setElideType(bool Val) { ElideType = Val; }
647   bool getElideType() { return ElideType; }
648 
649   /// Set tree printing, to outputting the template difference in a
650   /// tree format.
651   void setPrintTemplateTree(bool Val) { PrintTemplateTree = Val; }
652   bool getPrintTemplateTree() { return PrintTemplateTree; }
653 
654   /// Set color printing, so the type diffing will inject color markers
655   /// into the output.
656   void setShowColors(bool Val) { ShowColors = Val; }
657   bool getShowColors() { return ShowColors; }
658 
659   /// Specify which overload candidates to show when overload resolution
660   /// fails.
661   ///
662   /// By default, we show all candidates.
663   void setShowOverloads(OverloadsShown Val) {
664     ShowOverloads = Val;
665   }
666   OverloadsShown getShowOverloads() const { return ShowOverloads; }
667 
668   /// Pretend that the last diagnostic issued was ignored, so any
669   /// subsequent notes will be suppressed, or restore a prior ignoring
670   /// state after ignoring some diagnostics and their notes, possibly in
671   /// the middle of another diagnostic.
672   ///
673   /// This can be used by clients who suppress diagnostics themselves.
674   void setLastDiagnosticIgnored(bool Ignored) {
675     if (LastDiagLevel == DiagnosticIDs::Fatal)
676       FatalErrorOccurred = true;
677     LastDiagLevel = Ignored ? DiagnosticIDs::Ignored : DiagnosticIDs::Warning;
678   }
679 
680   /// Determine whether the previous diagnostic was ignored. This can
681   /// be used by clients that want to determine whether notes attached to a
682   /// diagnostic will be suppressed.
683   bool isLastDiagnosticIgnored() const {
684     return LastDiagLevel == DiagnosticIDs::Ignored;
685   }
686 
687   /// Controls whether otherwise-unmapped extension diagnostics are
688   /// mapped onto ignore/warning/error.
689   ///
690   /// This corresponds to the GCC -pedantic and -pedantic-errors option.
691   void setExtensionHandlingBehavior(diag::Severity H) {
692     GetCurDiagState()->ExtBehavior = H;
693   }
694   diag::Severity getExtensionHandlingBehavior() const {
695     return GetCurDiagState()->ExtBehavior;
696   }
697 
698   /// Counter bumped when an __extension__  block is/ encountered.
699   ///
700   /// When non-zero, all extension diagnostics are entirely silenced, no
701   /// matter how they are mapped.
702   void IncrementAllExtensionsSilenced() { ++AllExtensionsSilenced; }
703   void DecrementAllExtensionsSilenced() { --AllExtensionsSilenced; }
704   bool hasAllExtensionsSilenced() { return AllExtensionsSilenced != 0; }
705 
706   /// This allows the client to specify that certain warnings are
707   /// ignored.
708   ///
709   /// Notes can never be mapped, errors can only be mapped to fatal, and
710   /// WARNINGs and EXTENSIONs can be mapped arbitrarily.
711   ///
712   /// \param Loc The source location that this change of diagnostic state should
713   /// take affect. It can be null if we are setting the latest state.
714   void setSeverity(diag::kind Diag, diag::Severity Map, SourceLocation Loc);
715 
716   /// Change an entire diagnostic group (e.g. "unknown-pragmas") to
717   /// have the specified mapping.
718   ///
719   /// \returns true (and ignores the request) if "Group" was unknown, false
720   /// otherwise.
721   ///
722   /// \param Flavor The flavor of group to affect. -Rfoo does not affect the
723   /// state of the -Wfoo group and vice versa.
724   ///
725   /// \param Loc The source location that this change of diagnostic state should
726   /// take affect. It can be null if we are setting the state from command-line.
727   bool setSeverityForGroup(diag::Flavor Flavor, StringRef Group,
728                            diag::Severity Map,
729                            SourceLocation Loc = SourceLocation());
730 
731   /// Set the warning-as-error flag for the given diagnostic group.
732   ///
733   /// This function always only operates on the current diagnostic state.
734   ///
735   /// \returns True if the given group is unknown, false otherwise.
736   bool setDiagnosticGroupWarningAsError(StringRef Group, bool Enabled);
737 
738   /// Set the error-as-fatal flag for the given diagnostic group.
739   ///
740   /// This function always only operates on the current diagnostic state.
741   ///
742   /// \returns True if the given group is unknown, false otherwise.
743   bool setDiagnosticGroupErrorAsFatal(StringRef Group, bool Enabled);
744 
745   /// Add the specified mapping to all diagnostics of the specified
746   /// flavor.
747   ///
748   /// Mainly to be used by -Wno-everything to disable all warnings but allow
749   /// subsequent -W options to enable specific warnings.
750   void setSeverityForAll(diag::Flavor Flavor, diag::Severity Map,
751                          SourceLocation Loc = SourceLocation());
752 
753   bool hasErrorOccurred() const { return ErrorOccurred; }
754 
755   /// Errors that actually prevent compilation, not those that are
756   /// upgraded from a warning by -Werror.
757   bool hasUncompilableErrorOccurred() const {
758     return UncompilableErrorOccurred;
759   }
760   bool hasFatalErrorOccurred() const { return FatalErrorOccurred; }
761 
762   /// Determine whether any kind of unrecoverable error has occurred.
763   bool hasUnrecoverableErrorOccurred() const {
764     return FatalErrorOccurred || UnrecoverableErrorOccurred;
765   }
766 
767   unsigned getNumWarnings() const { return NumWarnings; }
768 
769   void setNumWarnings(unsigned NumWarnings) {
770     this->NumWarnings = NumWarnings;
771   }
772 
773   /// Return an ID for a diagnostic with the specified format string and
774   /// level.
775   ///
776   /// If this is the first request for this diagnostic, it is registered and
777   /// created, otherwise the existing ID is returned.
778   ///
779   /// \param FormatString A fixed diagnostic format string that will be hashed
780   /// and mapped to a unique DiagID.
781   template <unsigned N>
782   unsigned getCustomDiagID(Level L, const char (&FormatString)[N]) {
783     return Diags->getCustomDiagID((DiagnosticIDs::Level)L,
784                                   StringRef(FormatString, N - 1));
785   }
786 
787   /// Converts a diagnostic argument (as an intptr_t) into the string
788   /// that represents it.
789   void ConvertArgToString(ArgumentKind Kind, intptr_t Val,
790                           StringRef Modifier, StringRef Argument,
791                           ArrayRef<ArgumentValue> PrevArgs,
792                           SmallVectorImpl<char> &Output,
793                           ArrayRef<intptr_t> QualTypeVals) const {
794     ArgToStringFn(Kind, Val, Modifier, Argument, PrevArgs, Output,
795                   ArgToStringCookie, QualTypeVals);
796   }
797 
798   void SetArgToStringFn(ArgToStringFnTy Fn, void *Cookie) {
799     ArgToStringFn = Fn;
800     ArgToStringCookie = Cookie;
801   }
802 
803   /// Note that the prior diagnostic was emitted by some other
804   /// \c DiagnosticsEngine, and we may be attaching a note to that diagnostic.
805   void notePriorDiagnosticFrom(const DiagnosticsEngine &Other) {
806     LastDiagLevel = Other.LastDiagLevel;
807   }
808 
809   /// Reset the state of the diagnostic object to its initial
810   /// configuration.
811   void Reset();
812 
813   //===--------------------------------------------------------------------===//
814   // DiagnosticsEngine classification and reporting interfaces.
815   //
816 
817   /// Determine whether the diagnostic is known to be ignored.
818   ///
819   /// This can be used to opportunistically avoid expensive checks when it's
820   /// known for certain that the diagnostic has been suppressed at the
821   /// specified location \p Loc.
822   ///
823   /// \param Loc The source location we are interested in finding out the
824   /// diagnostic state. Can be null in order to query the latest state.
825   bool isIgnored(unsigned DiagID, SourceLocation Loc) const {
826     return Diags->getDiagnosticSeverity(DiagID, Loc, *this) ==
827            diag::Severity::Ignored;
828   }
829 
830   /// Based on the way the client configured the DiagnosticsEngine
831   /// object, classify the specified diagnostic ID into a Level, consumable by
832   /// the DiagnosticConsumer.
833   ///
834   /// To preserve invariant assumptions, this function should not be used to
835   /// influence parse or semantic analysis actions. Instead consider using
836   /// \c isIgnored().
837   ///
838   /// \param Loc The source location we are interested in finding out the
839   /// diagnostic state. Can be null in order to query the latest state.
840   Level getDiagnosticLevel(unsigned DiagID, SourceLocation Loc) const {
841     return (Level)Diags->getDiagnosticLevel(DiagID, Loc, *this);
842   }
843 
844   /// Issue the message to the client.
845   ///
846   /// This actually returns an instance of DiagnosticBuilder which emits the
847   /// diagnostics (through @c ProcessDiag) when it is destroyed.
848   ///
849   /// \param DiagID A member of the @c diag::kind enum.
850   /// \param Loc Represents the source location associated with the diagnostic,
851   /// which can be an invalid location if no position information is available.
852   inline DiagnosticBuilder Report(SourceLocation Loc, unsigned DiagID);
853   inline DiagnosticBuilder Report(unsigned DiagID);
854 
855   void Report(const StoredDiagnostic &storedDiag);
856 
857   /// Determine whethere there is already a diagnostic in flight.
858   bool isDiagnosticInFlight() const {
859     return CurDiagID != std::numeric_limits<unsigned>::max();
860   }
861 
862   /// Set the "delayed" diagnostic that will be emitted once
863   /// the current diagnostic completes.
864   ///
865   ///  If a diagnostic is already in-flight but the front end must
866   ///  report a problem (e.g., with an inconsistent file system
867   ///  state), this routine sets a "delayed" diagnostic that will be
868   ///  emitted after the current diagnostic completes. This should
869   ///  only be used for fatal errors detected at inconvenient
870   ///  times. If emitting a delayed diagnostic causes a second delayed
871   ///  diagnostic to be introduced, that second delayed diagnostic
872   ///  will be ignored.
873   ///
874   /// \param DiagID The ID of the diagnostic being delayed.
875   ///
876   /// \param Arg1 A string argument that will be provided to the
877   /// diagnostic. A copy of this string will be stored in the
878   /// DiagnosticsEngine object itself.
879   ///
880   /// \param Arg2 A string argument that will be provided to the
881   /// diagnostic. A copy of this string will be stored in the
882   /// DiagnosticsEngine object itself.
883   ///
884   /// \param Arg3 A string argument that will be provided to the
885   /// diagnostic. A copy of this string will be stored in the
886   /// DiagnosticsEngine object itself.
887   void SetDelayedDiagnostic(unsigned DiagID, StringRef Arg1 = "",
888                             StringRef Arg2 = "", StringRef Arg3 = "");
889 
890   /// Clear out the current diagnostic.
891   void Clear() { CurDiagID = std::numeric_limits<unsigned>::max(); }
892 
893   /// Return the value associated with this diagnostic flag.
894   StringRef getFlagValue() const { return FlagValue; }
895 
896 private:
897   // This is private state used by DiagnosticBuilder.  We put it here instead of
898   // in DiagnosticBuilder in order to keep DiagnosticBuilder a small lightweight
899   // object.  This implementation choice means that we can only have one
900   // diagnostic "in flight" at a time, but this seems to be a reasonable
901   // tradeoff to keep these objects small.  Assertions verify that only one
902   // diagnostic is in flight at a time.
903   friend class Diagnostic;
904   friend class DiagnosticBuilder;
905   friend class DiagnosticErrorTrap;
906   friend class DiagnosticIDs;
907   friend class PartialDiagnostic;
908 
909   /// Report the delayed diagnostic.
910   void ReportDelayed();
911 
912   /// The location of the current diagnostic that is in flight.
913   SourceLocation CurDiagLoc;
914 
915   /// The ID of the current diagnostic that is in flight.
916   ///
917   /// This is set to std::numeric_limits<unsigned>::max() when there is no
918   /// diagnostic in flight.
919   unsigned CurDiagID;
920 
921   enum {
922     /// The maximum number of arguments we can hold.
923     ///
924     /// We currently only support up to 10 arguments (%0-%9).  A single
925     /// diagnostic with more than that almost certainly has to be simplified
926     /// anyway.
927     MaxArguments = 10,
928   };
929 
930   /// The number of entries in Arguments.
931   signed char NumDiagArgs;
932 
933   /// Specifies whether an argument is in DiagArgumentsStr or
934   /// in DiagArguments.
935   ///
936   /// This is an array of ArgumentKind::ArgumentKind enum values, one for each
937   /// argument.
938   unsigned char DiagArgumentsKind[MaxArguments];
939 
940   /// Holds the values of each string argument for the current
941   /// diagnostic.
942   ///
943   /// This is only used when the corresponding ArgumentKind is ak_std_string.
944   std::string DiagArgumentsStr[MaxArguments];
945 
946   /// The values for the various substitution positions.
947   ///
948   /// This is used when the argument is not an std::string.  The specific
949   /// value is mangled into an intptr_t and the interpretation depends on
950   /// exactly what sort of argument kind it is.
951   intptr_t DiagArgumentsVal[MaxArguments];
952 
953   /// The list of ranges added to this diagnostic.
954   SmallVector<CharSourceRange, 8> DiagRanges;
955 
956   /// If valid, provides a hint with some code to insert, remove,
957   /// or modify at a particular position.
958   SmallVector<FixItHint, 8> DiagFixItHints;
959 
960   DiagnosticMapping makeUserMapping(diag::Severity Map, SourceLocation L) {
961     bool isPragma = L.isValid();
962     DiagnosticMapping Mapping =
963         DiagnosticMapping::Make(Map, /*IsUser=*/true, isPragma);
964 
965     // If this is a pragma mapping, then set the diagnostic mapping flags so
966     // that we override command line options.
967     if (isPragma) {
968       Mapping.setNoWarningAsError(true);
969       Mapping.setNoErrorAsFatal(true);
970     }
971 
972     return Mapping;
973   }
974 
975   /// Used to report a diagnostic that is finally fully formed.
976   ///
977   /// \returns true if the diagnostic was emitted, false if it was suppressed.
978   bool ProcessDiag() {
979     return Diags->ProcessDiag(*this);
980   }
981 
982   /// @name Diagnostic Emission
983   /// @{
984 protected:
985   friend class ASTReader;
986   friend class ASTWriter;
987 
988   // Sema requires access to the following functions because the current design
989   // of SFINAE requires it to use its own SemaDiagnosticBuilder, which needs to
990   // access us directly to ensure we minimize the emitted code for the common
991   // Sema::Diag() patterns.
992   friend class Sema;
993 
994   /// Emit the current diagnostic and clear the diagnostic state.
995   ///
996   /// \param Force Emit the diagnostic regardless of suppression settings.
997   bool EmitCurrentDiagnostic(bool Force = false);
998 
999   unsigned getCurrentDiagID() const { return CurDiagID; }
1000 
1001   SourceLocation getCurrentDiagLoc() const { return CurDiagLoc; }
1002 
1003   /// @}
1004 };
1005 
1006 /// RAII class that determines when any errors have occurred
1007 /// between the time the instance was created and the time it was
1008 /// queried.
1009 class DiagnosticErrorTrap {
1010   DiagnosticsEngine &Diag;
1011   unsigned NumErrors;
1012   unsigned NumUnrecoverableErrors;
1013 
1014 public:
1015   explicit DiagnosticErrorTrap(DiagnosticsEngine &Diag)
1016       : Diag(Diag) { reset(); }
1017 
1018   /// Determine whether any errors have occurred since this
1019   /// object instance was created.
1020   bool hasErrorOccurred() const {
1021     return Diag.TrapNumErrorsOccurred > NumErrors;
1022   }
1023 
1024   /// Determine whether any unrecoverable errors have occurred since this
1025   /// object instance was created.
1026   bool hasUnrecoverableErrorOccurred() const {
1027     return Diag.TrapNumUnrecoverableErrorsOccurred > NumUnrecoverableErrors;
1028   }
1029 
1030   /// Set to initial state of "no errors occurred".
1031   void reset() {
1032     NumErrors = Diag.TrapNumErrorsOccurred;
1033     NumUnrecoverableErrors = Diag.TrapNumUnrecoverableErrorsOccurred;
1034   }
1035 };
1036 
1037 //===----------------------------------------------------------------------===//
1038 // DiagnosticBuilder
1039 //===----------------------------------------------------------------------===//
1040 
1041 /// A little helper class used to produce diagnostics.
1042 ///
1043 /// This is constructed by the DiagnosticsEngine::Report method, and
1044 /// allows insertion of extra information (arguments and source ranges) into
1045 /// the currently "in flight" diagnostic.  When the temporary for the builder
1046 /// is destroyed, the diagnostic is issued.
1047 ///
1048 /// Note that many of these will be created as temporary objects (many call
1049 /// sites), so we want them to be small and we never want their address taken.
1050 /// This ensures that compilers with somewhat reasonable optimizers will promote
1051 /// the common fields to registers, eliminating increments of the NumArgs field,
1052 /// for example.
1053 class DiagnosticBuilder {
1054   friend class DiagnosticsEngine;
1055   friend class PartialDiagnostic;
1056 
1057   mutable DiagnosticsEngine *DiagObj = nullptr;
1058   mutable unsigned NumArgs = 0;
1059 
1060   /// Status variable indicating if this diagnostic is still active.
1061   ///
1062   // NOTE: This field is redundant with DiagObj (IsActive iff (DiagObj == 0)),
1063   // but LLVM is not currently smart enough to eliminate the null check that
1064   // Emit() would end up with if we used that as our status variable.
1065   mutable bool IsActive = false;
1066 
1067   /// Flag indicating that this diagnostic is being emitted via a
1068   /// call to ForceEmit.
1069   mutable bool IsForceEmit = false;
1070 
1071   DiagnosticBuilder() = default;
1072 
1073   explicit DiagnosticBuilder(DiagnosticsEngine *diagObj)
1074       : DiagObj(diagObj), IsActive(true) {
1075     assert(diagObj && "DiagnosticBuilder requires a valid DiagnosticsEngine!");
1076     diagObj->DiagRanges.clear();
1077     diagObj->DiagFixItHints.clear();
1078   }
1079 
1080 protected:
1081   void FlushCounts() {
1082     DiagObj->NumDiagArgs = NumArgs;
1083   }
1084 
1085   /// Clear out the current diagnostic.
1086   void Clear() const {
1087     DiagObj = nullptr;
1088     IsActive = false;
1089     IsForceEmit = false;
1090   }
1091 
1092   /// Determine whether this diagnostic is still active.
1093   bool isActive() const { return IsActive; }
1094 
1095   /// Force the diagnostic builder to emit the diagnostic now.
1096   ///
1097   /// Once this function has been called, the DiagnosticBuilder object
1098   /// should not be used again before it is destroyed.
1099   ///
1100   /// \returns true if a diagnostic was emitted, false if the
1101   /// diagnostic was suppressed.
1102   bool Emit() {
1103     // If this diagnostic is inactive, then its soul was stolen by the copy ctor
1104     // (or by a subclass, as in SemaDiagnosticBuilder).
1105     if (!isActive()) return false;
1106 
1107     // When emitting diagnostics, we set the final argument count into
1108     // the DiagnosticsEngine object.
1109     FlushCounts();
1110 
1111     // Process the diagnostic.
1112     bool Result = DiagObj->EmitCurrentDiagnostic(IsForceEmit);
1113 
1114     // This diagnostic is dead.
1115     Clear();
1116 
1117     return Result;
1118   }
1119 
1120 public:
1121   /// Copy constructor.  When copied, this "takes" the diagnostic info from the
1122   /// input and neuters it.
1123   DiagnosticBuilder(const DiagnosticBuilder &D) {
1124     DiagObj = D.DiagObj;
1125     IsActive = D.IsActive;
1126     IsForceEmit = D.IsForceEmit;
1127     D.Clear();
1128     NumArgs = D.NumArgs;
1129   }
1130 
1131   DiagnosticBuilder &operator=(const DiagnosticBuilder &) = delete;
1132 
1133   /// Emits the diagnostic.
1134   ~DiagnosticBuilder() {
1135     Emit();
1136   }
1137 
1138   /// Forces the diagnostic to be emitted.
1139   const DiagnosticBuilder &setForceEmit() const {
1140     IsForceEmit = true;
1141     return *this;
1142   }
1143 
1144   /// Conversion of DiagnosticBuilder to bool always returns \c true.
1145   ///
1146   /// This allows is to be used in boolean error contexts (where \c true is
1147   /// used to indicate that an error has occurred), like:
1148   /// \code
1149   /// return Diag(...);
1150   /// \endcode
1151   operator bool() const { return true; }
1152 
1153   void AddString(StringRef S) const {
1154     assert(isActive() && "Clients must not add to cleared diagnostic!");
1155     assert(NumArgs < DiagnosticsEngine::MaxArguments &&
1156            "Too many arguments to diagnostic!");
1157     DiagObj->DiagArgumentsKind[NumArgs] = DiagnosticsEngine::ak_std_string;
1158     DiagObj->DiagArgumentsStr[NumArgs++] = S;
1159   }
1160 
1161   void AddTaggedVal(intptr_t V, DiagnosticsEngine::ArgumentKind Kind) const {
1162     assert(isActive() && "Clients must not add to cleared diagnostic!");
1163     assert(NumArgs < DiagnosticsEngine::MaxArguments &&
1164            "Too many arguments to diagnostic!");
1165     DiagObj->DiagArgumentsKind[NumArgs] = Kind;
1166     DiagObj->DiagArgumentsVal[NumArgs++] = V;
1167   }
1168 
1169   void AddSourceRange(const CharSourceRange &R) const {
1170     assert(isActive() && "Clients must not add to cleared diagnostic!");
1171     DiagObj->DiagRanges.push_back(R);
1172   }
1173 
1174   void AddFixItHint(const FixItHint &Hint) const {
1175     assert(isActive() && "Clients must not add to cleared diagnostic!");
1176     if (!Hint.isNull())
1177       DiagObj->DiagFixItHints.push_back(Hint);
1178   }
1179 
1180   void addFlagValue(StringRef V) const { DiagObj->FlagValue = V; }
1181 };
1182 
1183 struct AddFlagValue {
1184   StringRef Val;
1185 
1186   explicit AddFlagValue(StringRef V) : Val(V) {}
1187 };
1188 
1189 /// Register a value for the flag in the current diagnostic. This
1190 /// value will be shown as the suffix "=value" after the flag name. It is
1191 /// useful in cases where the diagnostic flag accepts values (e.g.,
1192 /// -Rpass or -Wframe-larger-than).
1193 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1194                                            const AddFlagValue V) {
1195   DB.addFlagValue(V.Val);
1196   return DB;
1197 }
1198 
1199 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1200                                            StringRef S) {
1201   DB.AddString(S);
1202   return DB;
1203 }
1204 
1205 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1206                                            const char *Str) {
1207   DB.AddTaggedVal(reinterpret_cast<intptr_t>(Str),
1208                   DiagnosticsEngine::ak_c_string);
1209   return DB;
1210 }
1211 
1212 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB, int I) {
1213   DB.AddTaggedVal(I, DiagnosticsEngine::ak_sint);
1214   return DB;
1215 }
1216 
1217 // We use enable_if here to prevent that this overload is selected for
1218 // pointers or other arguments that are implicitly convertible to bool.
1219 template <typename T>
1220 inline
1221 typename std::enable_if<std::is_same<T, bool>::value,
1222                         const DiagnosticBuilder &>::type
1223 operator<<(const DiagnosticBuilder &DB, T I) {
1224   DB.AddTaggedVal(I, DiagnosticsEngine::ak_sint);
1225   return DB;
1226 }
1227 
1228 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1229                                            unsigned I) {
1230   DB.AddTaggedVal(I, DiagnosticsEngine::ak_uint);
1231   return DB;
1232 }
1233 
1234 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1235                                            tok::TokenKind I) {
1236   DB.AddTaggedVal(static_cast<unsigned>(I), DiagnosticsEngine::ak_tokenkind);
1237   return DB;
1238 }
1239 
1240 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1241                                            const IdentifierInfo *II) {
1242   DB.AddTaggedVal(reinterpret_cast<intptr_t>(II),
1243                   DiagnosticsEngine::ak_identifierinfo);
1244   return DB;
1245 }
1246 
1247 // Adds a DeclContext to the diagnostic. The enable_if template magic is here
1248 // so that we only match those arguments that are (statically) DeclContexts;
1249 // other arguments that derive from DeclContext (e.g., RecordDecls) will not
1250 // match.
1251 template <typename T>
1252 inline typename std::enable_if<
1253     std::is_same<typename std::remove_const<T>::type, DeclContext>::value,
1254     const DiagnosticBuilder &>::type
1255 operator<<(const DiagnosticBuilder &DB, T *DC) {
1256   DB.AddTaggedVal(reinterpret_cast<intptr_t>(DC),
1257                   DiagnosticsEngine::ak_declcontext);
1258   return DB;
1259 }
1260 
1261 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1262                                            SourceRange R) {
1263   DB.AddSourceRange(CharSourceRange::getTokenRange(R));
1264   return DB;
1265 }
1266 
1267 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1268                                            ArrayRef<SourceRange> Ranges) {
1269   for (SourceRange R : Ranges)
1270     DB.AddSourceRange(CharSourceRange::getTokenRange(R));
1271   return DB;
1272 }
1273 
1274 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1275                                            const CharSourceRange &R) {
1276   DB.AddSourceRange(R);
1277   return DB;
1278 }
1279 
1280 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1281                                            const FixItHint &Hint) {
1282   DB.AddFixItHint(Hint);
1283   return DB;
1284 }
1285 
1286 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1287                                            ArrayRef<FixItHint> Hints) {
1288   for (const FixItHint &Hint : Hints)
1289     DB.AddFixItHint(Hint);
1290   return DB;
1291 }
1292 
1293 /// A nullability kind paired with a bit indicating whether it used a
1294 /// context-sensitive keyword.
1295 using DiagNullabilityKind = std::pair<NullabilityKind, bool>;
1296 
1297 const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1298                                     DiagNullabilityKind nullability);
1299 
1300 inline DiagnosticBuilder DiagnosticsEngine::Report(SourceLocation Loc,
1301                                                    unsigned DiagID) {
1302   assert(CurDiagID == std::numeric_limits<unsigned>::max() &&
1303          "Multiple diagnostics in flight at once!");
1304   CurDiagLoc = Loc;
1305   CurDiagID = DiagID;
1306   FlagValue.clear();
1307   return DiagnosticBuilder(this);
1308 }
1309 
1310 inline const DiagnosticBuilder &operator<<(const DiagnosticBuilder &DB,
1311                                            llvm::Error &&E) {
1312   DB.AddString(toString(std::move(E)));
1313   return DB;
1314 }
1315 
1316 inline DiagnosticBuilder DiagnosticsEngine::Report(unsigned DiagID) {
1317   return Report(SourceLocation(), DiagID);
1318 }
1319 
1320 //===----------------------------------------------------------------------===//
1321 // Diagnostic
1322 //===----------------------------------------------------------------------===//
1323 
1324 /// A little helper class (which is basically a smart pointer that forwards
1325 /// info from DiagnosticsEngine) that allows clients to enquire about the
1326 /// currently in-flight diagnostic.
1327 class Diagnostic {
1328   const DiagnosticsEngine *DiagObj;
1329   StringRef StoredDiagMessage;
1330 
1331 public:
1332   explicit Diagnostic(const DiagnosticsEngine *DO) : DiagObj(DO) {}
1333   Diagnostic(const DiagnosticsEngine *DO, StringRef storedDiagMessage)
1334       : DiagObj(DO), StoredDiagMessage(storedDiagMessage) {}
1335 
1336   const DiagnosticsEngine *getDiags() const { return DiagObj; }
1337   unsigned getID() const { return DiagObj->CurDiagID; }
1338   const SourceLocation &getLocation() const { return DiagObj->CurDiagLoc; }
1339   bool hasSourceManager() const { return DiagObj->hasSourceManager(); }
1340   SourceManager &getSourceManager() const { return DiagObj->getSourceManager();}
1341 
1342   unsigned getNumArgs() const { return DiagObj->NumDiagArgs; }
1343 
1344   /// Return the kind of the specified index.
1345   ///
1346   /// Based on the kind of argument, the accessors below can be used to get
1347   /// the value.
1348   ///
1349   /// \pre Idx < getNumArgs()
1350   DiagnosticsEngine::ArgumentKind getArgKind(unsigned Idx) const {
1351     assert(Idx < getNumArgs() && "Argument index out of range!");
1352     return (DiagnosticsEngine::ArgumentKind)DiagObj->DiagArgumentsKind[Idx];
1353   }
1354 
1355   /// Return the provided argument string specified by \p Idx.
1356   /// \pre getArgKind(Idx) == DiagnosticsEngine::ak_std_string
1357   const std::string &getArgStdStr(unsigned Idx) const {
1358     assert(getArgKind(Idx) == DiagnosticsEngine::ak_std_string &&
1359            "invalid argument accessor!");
1360     return DiagObj->DiagArgumentsStr[Idx];
1361   }
1362 
1363   /// Return the specified C string argument.
1364   /// \pre getArgKind(Idx) == DiagnosticsEngine::ak_c_string
1365   const char *getArgCStr(unsigned Idx) const {
1366     assert(getArgKind(Idx) == DiagnosticsEngine::ak_c_string &&
1367            "invalid argument accessor!");
1368     return reinterpret_cast<const char*>(DiagObj->DiagArgumentsVal[Idx]);
1369   }
1370 
1371   /// Return the specified signed integer argument.
1372   /// \pre getArgKind(Idx) == DiagnosticsEngine::ak_sint
1373   int getArgSInt(unsigned Idx) const {
1374     assert(getArgKind(Idx) == DiagnosticsEngine::ak_sint &&
1375            "invalid argument accessor!");
1376     return (int)DiagObj->DiagArgumentsVal[Idx];
1377   }
1378 
1379   /// Return the specified unsigned integer argument.
1380   /// \pre getArgKind(Idx) == DiagnosticsEngine::ak_uint
1381   unsigned getArgUInt(unsigned Idx) const {
1382     assert(getArgKind(Idx) == DiagnosticsEngine::ak_uint &&
1383            "invalid argument accessor!");
1384     return (unsigned)DiagObj->DiagArgumentsVal[Idx];
1385   }
1386 
1387   /// Return the specified IdentifierInfo argument.
1388   /// \pre getArgKind(Idx) == DiagnosticsEngine::ak_identifierinfo
1389   const IdentifierInfo *getArgIdentifier(unsigned Idx) const {
1390     assert(getArgKind(Idx) == DiagnosticsEngine::ak_identifierinfo &&
1391            "invalid argument accessor!");
1392     return reinterpret_cast<IdentifierInfo*>(DiagObj->DiagArgumentsVal[Idx]);
1393   }
1394 
1395   /// Return the specified non-string argument in an opaque form.
1396   /// \pre getArgKind(Idx) != DiagnosticsEngine::ak_std_string
1397   intptr_t getRawArg(unsigned Idx) const {
1398     assert(getArgKind(Idx) != DiagnosticsEngine::ak_std_string &&
1399            "invalid argument accessor!");
1400     return DiagObj->DiagArgumentsVal[Idx];
1401   }
1402 
1403   /// Return the number of source ranges associated with this diagnostic.
1404   unsigned getNumRanges() const {
1405     return DiagObj->DiagRanges.size();
1406   }
1407 
1408   /// \pre Idx < getNumRanges()
1409   const CharSourceRange &getRange(unsigned Idx) const {
1410     assert(Idx < getNumRanges() && "Invalid diagnostic range index!");
1411     return DiagObj->DiagRanges[Idx];
1412   }
1413 
1414   /// Return an array reference for this diagnostic's ranges.
1415   ArrayRef<CharSourceRange> getRanges() const {
1416     return DiagObj->DiagRanges;
1417   }
1418 
1419   unsigned getNumFixItHints() const {
1420     return DiagObj->DiagFixItHints.size();
1421   }
1422 
1423   const FixItHint &getFixItHint(unsigned Idx) const {
1424     assert(Idx < getNumFixItHints() && "Invalid index!");
1425     return DiagObj->DiagFixItHints[Idx];
1426   }
1427 
1428   ArrayRef<FixItHint> getFixItHints() const {
1429     return DiagObj->DiagFixItHints;
1430   }
1431 
1432   /// Format this diagnostic into a string, substituting the
1433   /// formal arguments into the %0 slots.
1434   ///
1435   /// The result is appended onto the \p OutStr array.
1436   void FormatDiagnostic(SmallVectorImpl<char> &OutStr) const;
1437 
1438   /// Format the given format-string into the output buffer using the
1439   /// arguments stored in this diagnostic.
1440   void FormatDiagnostic(const char *DiagStr, const char *DiagEnd,
1441                         SmallVectorImpl<char> &OutStr) const;
1442 };
1443 
1444 /**
1445  * Represents a diagnostic in a form that can be retained until its
1446  * corresponding source manager is destroyed.
1447  */
1448 class StoredDiagnostic {
1449   unsigned ID;
1450   DiagnosticsEngine::Level Level;
1451   FullSourceLoc Loc;
1452   std::string Message;
1453   std::vector<CharSourceRange> Ranges;
1454   std::vector<FixItHint> FixIts;
1455 
1456 public:
1457   StoredDiagnostic() = default;
1458   StoredDiagnostic(DiagnosticsEngine::Level Level, const Diagnostic &Info);
1459   StoredDiagnostic(DiagnosticsEngine::Level Level, unsigned ID,
1460                    StringRef Message);
1461   StoredDiagnostic(DiagnosticsEngine::Level Level, unsigned ID,
1462                    StringRef Message, FullSourceLoc Loc,
1463                    ArrayRef<CharSourceRange> Ranges,
1464                    ArrayRef<FixItHint> Fixits);
1465 
1466   /// Evaluates true when this object stores a diagnostic.
1467   explicit operator bool() const { return !Message.empty(); }
1468 
1469   unsigned getID() const { return ID; }
1470   DiagnosticsEngine::Level getLevel() const { return Level; }
1471   const FullSourceLoc &getLocation() const { return Loc; }
1472   StringRef getMessage() const { return Message; }
1473 
1474   void setLocation(FullSourceLoc Loc) { this->Loc = Loc; }
1475 
1476   using range_iterator = std::vector<CharSourceRange>::const_iterator;
1477 
1478   range_iterator range_begin() const { return Ranges.begin(); }
1479   range_iterator range_end() const { return Ranges.end(); }
1480   unsigned range_size() const { return Ranges.size(); }
1481 
1482   ArrayRef<CharSourceRange> getRanges() const {
1483     return llvm::makeArrayRef(Ranges);
1484   }
1485 
1486   using fixit_iterator = std::vector<FixItHint>::const_iterator;
1487 
1488   fixit_iterator fixit_begin() const { return FixIts.begin(); }
1489   fixit_iterator fixit_end() const { return FixIts.end(); }
1490   unsigned fixit_size() const { return FixIts.size(); }
1491 
1492   ArrayRef<FixItHint> getFixIts() const {
1493     return llvm::makeArrayRef(FixIts);
1494   }
1495 };
1496 
1497 /// Abstract interface, implemented by clients of the front-end, which
1498 /// formats and prints fully processed diagnostics.
1499 class DiagnosticConsumer {
1500 protected:
1501   unsigned NumWarnings = 0;       ///< Number of warnings reported
1502   unsigned NumErrors = 0;         ///< Number of errors reported
1503 
1504 public:
1505   DiagnosticConsumer() = default;
1506   virtual ~DiagnosticConsumer();
1507 
1508   unsigned getNumErrors() const { return NumErrors; }
1509   unsigned getNumWarnings() const { return NumWarnings; }
1510   virtual void clear() { NumWarnings = NumErrors = 0; }
1511 
1512   /// Callback to inform the diagnostic client that processing
1513   /// of a source file is beginning.
1514   ///
1515   /// Note that diagnostics may be emitted outside the processing of a source
1516   /// file, for example during the parsing of command line options. However,
1517   /// diagnostics with source range information are required to only be emitted
1518   /// in between BeginSourceFile() and EndSourceFile().
1519   ///
1520   /// \param LangOpts The language options for the source file being processed.
1521   /// \param PP The preprocessor object being used for the source; this is
1522   /// optional, e.g., it may not be present when processing AST source files.
1523   virtual void BeginSourceFile(const LangOptions &LangOpts,
1524                                const Preprocessor *PP = nullptr) {}
1525 
1526   /// Callback to inform the diagnostic client that processing
1527   /// of a source file has ended.
1528   ///
1529   /// The diagnostic client should assume that any objects made available via
1530   /// BeginSourceFile() are inaccessible.
1531   virtual void EndSourceFile() {}
1532 
1533   /// Callback to inform the diagnostic client that processing of all
1534   /// source files has ended.
1535   virtual void finish() {}
1536 
1537   /// Indicates whether the diagnostics handled by this
1538   /// DiagnosticConsumer should be included in the number of diagnostics
1539   /// reported by DiagnosticsEngine.
1540   ///
1541   /// The default implementation returns true.
1542   virtual bool IncludeInDiagnosticCounts() const;
1543 
1544   /// Handle this diagnostic, reporting it to the user or
1545   /// capturing it to a log as needed.
1546   ///
1547   /// The default implementation just keeps track of the total number of
1548   /// warnings and errors.
1549   virtual void HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
1550                                 const Diagnostic &Info);
1551 };
1552 
1553 /// A diagnostic client that ignores all diagnostics.
1554 class IgnoringDiagConsumer : public DiagnosticConsumer {
1555   virtual void anchor();
1556 
1557   void HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
1558                         const Diagnostic &Info) override {
1559     // Just ignore it.
1560   }
1561 };
1562 
1563 /// Diagnostic consumer that forwards diagnostics along to an
1564 /// existing, already-initialized diagnostic consumer.
1565 ///
1566 class ForwardingDiagnosticConsumer : public DiagnosticConsumer {
1567   DiagnosticConsumer &Target;
1568 
1569 public:
1570   ForwardingDiagnosticConsumer(DiagnosticConsumer &Target) : Target(Target) {}
1571   ~ForwardingDiagnosticConsumer() override;
1572 
1573   void HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
1574                         const Diagnostic &Info) override;
1575   void clear() override;
1576 
1577   bool IncludeInDiagnosticCounts() const override;
1578 };
1579 
1580 // Struct used for sending info about how a type should be printed.
1581 struct TemplateDiffTypes {
1582   intptr_t FromType;
1583   intptr_t ToType;
1584   unsigned PrintTree : 1;
1585   unsigned PrintFromType : 1;
1586   unsigned ElideType : 1;
1587   unsigned ShowColors : 1;
1588 
1589   // The printer sets this variable to true if the template diff was used.
1590   unsigned TemplateDiffUsed : 1;
1591 };
1592 
1593 /// Special character that the diagnostic printer will use to toggle the bold
1594 /// attribute.  The character itself will be not be printed.
1595 const char ToggleHighlight = 127;
1596 
1597 /// ProcessWarningOptions - Initialize the diagnostic client and process the
1598 /// warning options specified on the command line.
1599 void ProcessWarningOptions(DiagnosticsEngine &Diags,
1600                            const DiagnosticOptions &Opts,
1601                            bool ReportDiags = true);
1602 
1603 } // namespace clang
1604 
1605 #endif // LLVM_CLANG_BASIC_DIAGNOSTIC_H
1606