clang  8.0.0
InterpolatingCompilationDatabase.cpp
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1 //===- InterpolatingCompilationDatabase.cpp ---------------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // InterpolatingCompilationDatabase wraps another CompilationDatabase and
11 // attempts to heuristically determine appropriate compile commands for files
12 // that are not included, such as headers or newly created files.
13 //
14 // Motivating cases include:
15 // Header files that live next to their implementation files. These typically
16 // share a base filename. (libclang/CXString.h, libclang/CXString.cpp).
17 // Some projects separate headers from includes. Filenames still typically
18 // match, maybe other path segments too. (include/llvm/IR/Use.h, lib/IR/Use.cc).
19 // Matches are sometimes only approximate (Sema.h, SemaDecl.cpp). This goes
20 // for directories too (Support/Unix/Process.inc, lib/Support/Process.cpp).
21 // Even if we can't find a "right" compile command, even a random one from
22 // the project will tend to get important flags like -I and -x right.
23 //
24 // We "borrow" the compile command for the closest available file:
25 // - points are awarded if the filename matches (ignoring extension)
26 // - points are awarded if the directory structure matches
27 // - ties are broken by length of path prefix match
28 //
29 // The compile command is adjusted, replacing the filename and removing output
30 // file arguments. The -x and -std flags may be affected too.
31 //
32 // Source language is a tricky issue: is it OK to use a .c file's command
33 // for building a .cc file? What language is a .h file in?
34 // - We only consider compile commands for c-family languages as candidates.
35 // - For files whose language is implied by the filename (e.g. .m, .hpp)
36 // we prefer candidates from the same language.
37 // If we must cross languages, we drop any -x and -std flags.
38 // - For .h files, candidates from any c-family language are acceptable.
39 // We use the candidate's language, inserting e.g. -x c++-header.
40 //
41 // This class is only useful when wrapping databases that can enumerate all
42 // their compile commands. If getAllFilenames() is empty, no inference occurs.
43 //
44 //===----------------------------------------------------------------------===//
45 
46 #include "clang/Driver/Options.h"
47 #include "clang/Driver/Types.h"
50 #include "llvm/ADT/DenseMap.h"
51 #include "llvm/ADT/Optional.h"
52 #include "llvm/ADT/StringExtras.h"
53 #include "llvm/ADT/StringSwitch.h"
54 #include "llvm/Option/ArgList.h"
55 #include "llvm/Option/OptTable.h"
56 #include "llvm/Support/Debug.h"
57 #include "llvm/Support/Path.h"
58 #include "llvm/Support/StringSaver.h"
59 #include "llvm/Support/raw_ostream.h"
60 #include <memory>
61 
62 namespace clang {
63 namespace tooling {
64 namespace {
65 using namespace llvm;
66 namespace types = clang::driver::types;
67 namespace path = llvm::sys::path;
68 
69 // The length of the prefix these two strings have in common.
70 size_t matchingPrefix(StringRef L, StringRef R) {
71  size_t Limit = std::min(L.size(), R.size());
72  for (size_t I = 0; I < Limit; ++I)
73  if (L[I] != R[I])
74  return I;
75  return Limit;
76 }
77 
78 // A comparator for searching SubstringWithIndexes with std::equal_range etc.
79 // Optionaly prefix semantics: compares equal if the key is a prefix.
80 template <bool Prefix> struct Less {
81  bool operator()(StringRef Key, std::pair<StringRef, size_t> Value) const {
82  StringRef V = Prefix ? Value.first.substr(0, Key.size()) : Value.first;
83  return Key < V;
84  }
85  bool operator()(std::pair<StringRef, size_t> Value, StringRef Key) const {
86  StringRef V = Prefix ? Value.first.substr(0, Key.size()) : Value.first;
87  return V < Key;
88  }
89 };
90 
91 // Infer type from filename. If we might have gotten it wrong, set *Certain.
92 // *.h will be inferred as a C header, but not certain.
93 types::ID guessType(StringRef Filename, bool *Certain = nullptr) {
94  // path::extension is ".cpp", lookupTypeForExtension wants "cpp".
95  auto Lang =
96  types::lookupTypeForExtension(path::extension(Filename).substr(1));
97  if (Certain)
98  *Certain = Lang != types::TY_CHeader && Lang != types::TY_INVALID;
99  return Lang;
100 }
101 
102 // Return Lang as one of the canonical supported types.
103 // e.g. c-header --> c; fortran --> TY_INVALID
104 static types::ID foldType(types::ID Lang) {
105  switch (Lang) {
106  case types::TY_C:
107  case types::TY_CHeader:
108  return types::TY_C;
109  case types::TY_ObjC:
110  case types::TY_ObjCHeader:
111  return types::TY_ObjC;
112  case types::TY_CXX:
113  case types::TY_CXXHeader:
114  return types::TY_CXX;
115  case types::TY_ObjCXX:
116  case types::TY_ObjCXXHeader:
117  return types::TY_ObjCXX;
118  default:
119  return types::TY_INVALID;
120  }
121 }
122 
123 // A CompileCommand that can be applied to another file.
124 struct TransferableCommand {
125  // Flags that should not apply to all files are stripped from CommandLine.
126  CompileCommand Cmd;
127  // Language detected from -x or the filename. Never TY_INVALID.
129  // Standard specified by -std.
131  // Whether the command line is for the cl-compatible driver.
133 
134  TransferableCommand(CompileCommand C)
135  : Cmd(std::move(C)), Type(guessType(Cmd.Filename)),
136  ClangCLMode(checkIsCLMode(Cmd.CommandLine)) {
137  std::vector<std::string> OldArgs = std::move(Cmd.CommandLine);
138  Cmd.CommandLine.clear();
139 
140  // Wrap the old arguments in an InputArgList.
141  llvm::opt::InputArgList ArgList;
142  {
144  for (const std::string &S : OldArgs)
145  TmpArgv.push_back(S.c_str());
146  ArgList = {TmpArgv.begin(), TmpArgv.end()};
147  }
148 
149  // Parse the old args in order to strip out and record unwanted flags.
150  // We parse each argument individually so that we can retain the exact
151  // spelling of each argument; re-rendering is lossy for aliased flags.
152  // E.g. in CL mode, /W4 maps to -Wall.
153  auto OptTable = clang::driver::createDriverOptTable();
154  Cmd.CommandLine.emplace_back(OldArgs.front());
155  for (unsigned Pos = 1; Pos < OldArgs.size();) {
156  using namespace driver::options;
157 
158  const unsigned OldPos = Pos;
159  std::unique_ptr<llvm::opt::Arg> Arg(OptTable->ParseOneArg(
160  ArgList, Pos,
161  /* Include */ClangCLMode ? CoreOption | CLOption : 0,
162  /* Exclude */ClangCLMode ? 0 : CLOption));
163 
164  if (!Arg)
165  continue;
166 
167  const llvm::opt::Option &Opt = Arg->getOption();
168 
169  // Strip input and output files.
170  if (Opt.matches(OPT_INPUT) || Opt.matches(OPT_o) ||
171  (ClangCLMode && (Opt.matches(OPT__SLASH_Fa) ||
172  Opt.matches(OPT__SLASH_Fe) ||
173  Opt.matches(OPT__SLASH_Fi) ||
174  Opt.matches(OPT__SLASH_Fo))))
175  continue;
176 
177  // Strip -x, but record the overridden language.
178  if (const auto GivenType = tryParseTypeArg(*Arg)) {
179  Type = *GivenType;
180  continue;
181  }
182 
183  // Strip -std, but record the value.
184  if (const auto GivenStd = tryParseStdArg(*Arg)) {
185  if (*GivenStd != LangStandard::lang_unspecified)
186  Std = *GivenStd;
187  continue;
188  }
189 
190  Cmd.CommandLine.insert(Cmd.CommandLine.end(),
191  OldArgs.data() + OldPos, OldArgs.data() + Pos);
192  }
193 
194  if (Std != LangStandard::lang_unspecified) // -std take precedence over -x
195  Type = toType(LangStandard::getLangStandardForKind(Std).getLanguage());
196  Type = foldType(*Type);
197  // The contract is to store None instead of TY_INVALID.
198  if (Type == types::TY_INVALID)
199  Type = llvm::None;
200  }
201 
202  // Produce a CompileCommand for \p filename, based on this one.
203  CompileCommand transferTo(StringRef Filename) const {
204  CompileCommand Result = Cmd;
205  Result.Filename = Filename;
206  bool TypeCertain;
207  auto TargetType = guessType(Filename, &TypeCertain);
208  // If the filename doesn't determine the language (.h), transfer with -x.
209  if (TargetType != types::TY_INVALID && !TypeCertain && Type) {
210  TargetType = types::onlyPrecompileType(TargetType) // header?
212  : *Type;
213  if (ClangCLMode) {
214  const StringRef Flag = toCLFlag(TargetType);
215  if (!Flag.empty())
216  Result.CommandLine.push_back(Flag);
217  } else {
218  Result.CommandLine.push_back("-x");
219  Result.CommandLine.push_back(types::getTypeName(TargetType));
220  }
221  }
222  // --std flag may only be transferred if the language is the same.
223  // We may consider "translating" these, e.g. c++11 -> c11.
224  if (Std != LangStandard::lang_unspecified && foldType(TargetType) == Type) {
225  Result.CommandLine.emplace_back((
226  llvm::Twine(ClangCLMode ? "/std:" : "-std=") +
228  }
229  Result.CommandLine.push_back(Filename);
230  return Result;
231  }
232 
233 private:
234  // Determine whether the given command line is intended for the CL driver.
235  static bool checkIsCLMode(ArrayRef<std::string> CmdLine) {
236  // First look for --driver-mode.
237  for (StringRef S : llvm::reverse(CmdLine)) {
238  if (S.consume_front("--driver-mode="))
239  return S == "cl";
240  }
241 
242  // Otherwise just check the clang executable file name.
243  return llvm::sys::path::stem(CmdLine.front()).endswith_lower("cl");
244  }
245 
246  // Map the language from the --std flag to that of the -x flag.
247  static types::ID toType(InputKind::Language Lang) {
248  switch (Lang) {
249  case InputKind::C:
250  return types::TY_C;
251  case InputKind::CXX:
252  return types::TY_CXX;
253  case InputKind::ObjC:
254  return types::TY_ObjC;
255  case InputKind::ObjCXX:
256  return types::TY_ObjCXX;
257  default:
258  return types::TY_INVALID;
259  }
260  }
261 
262  // Convert a file type to the matching CL-style type flag.
263  static StringRef toCLFlag(types::ID Type) {
264  switch (Type) {
265  case types::TY_C:
266  case types::TY_CHeader:
267  return "/TC";
268  case types::TY_CXX:
269  case types::TY_CXXHeader:
270  return "/TP";
271  default:
272  return StringRef();
273  }
274  }
275 
276  // Try to interpret the argument as a type specifier, e.g. '-x'.
277  Optional<types::ID> tryParseTypeArg(const llvm::opt::Arg &Arg) {
278  const llvm::opt::Option &Opt = Arg.getOption();
279  using namespace driver::options;
280  if (ClangCLMode) {
281  if (Opt.matches(OPT__SLASH_TC) || Opt.matches(OPT__SLASH_Tc))
282  return types::TY_C;
283  if (Opt.matches(OPT__SLASH_TP) || Opt.matches(OPT__SLASH_Tp))
284  return types::TY_CXX;
285  } else {
286  if (Opt.matches(driver::options::OPT_x))
287  return types::lookupTypeForTypeSpecifier(Arg.getValue());
288  }
289  return None;
290  }
291 
292  // Try to interpret the argument as '-std='.
293  Optional<LangStandard::Kind> tryParseStdArg(const llvm::opt::Arg &Arg) {
294  using namespace driver::options;
295  if (Arg.getOption().matches(ClangCLMode ? OPT__SLASH_std : OPT_std_EQ)) {
296  return llvm::StringSwitch<LangStandard::Kind>(Arg.getValue())
297 #define LANGSTANDARD(id, name, lang, ...) .Case(name, LangStandard::lang_##id)
298 #define LANGSTANDARD_ALIAS(id, alias) .Case(alias, LangStandard::lang_##id)
299 #include "clang/Frontend/LangStandards.def"
300 #undef LANGSTANDARD_ALIAS
301 #undef LANGSTANDARD
303  }
304  return None;
305  }
306 };
307 
308 // Given a filename, FileIndex picks the best matching file from the underlying
309 // DB. This is the proxy file whose CompileCommand will be reused. The
310 // heuristics incorporate file name, extension, and directory structure.
311 // Strategy:
312 // - Build indexes of each of the substrings we want to look up by.
313 // These indexes are just sorted lists of the substrings.
314 // - Each criterion corresponds to a range lookup into the index, so we only
315 // need O(log N) string comparisons to determine scores.
316 //
317 // Apart from path proximity signals, also takes file extensions into account
318 // when scoring the candidates.
319 class FileIndex {
320 public:
321  FileIndex(std::vector<std::string> Files)
322  : OriginalPaths(std::move(Files)), Strings(Arena) {
323  // Sort commands by filename for determinism (index is a tiebreaker later).
324  llvm::sort(OriginalPaths);
325  Paths.reserve(OriginalPaths.size());
326  Types.reserve(OriginalPaths.size());
327  Stems.reserve(OriginalPaths.size());
328  for (size_t I = 0; I < OriginalPaths.size(); ++I) {
329  StringRef Path = Strings.save(StringRef(OriginalPaths[I]).lower());
330 
331  Paths.emplace_back(Path, I);
332  Types.push_back(foldType(guessType(Path)));
333  Stems.emplace_back(sys::path::stem(Path), I);
334  auto Dir = ++sys::path::rbegin(Path), DirEnd = sys::path::rend(Path);
335  for (int J = 0; J < DirectorySegmentsIndexed && Dir != DirEnd; ++J, ++Dir)
336  if (Dir->size() > ShortDirectorySegment) // not trivial ones
337  Components.emplace_back(*Dir, I);
338  }
339  llvm::sort(Paths);
340  llvm::sort(Stems);
341  llvm::sort(Components);
342  }
343 
344  bool empty() const { return Paths.empty(); }
345 
346  // Returns the path for the file that best fits OriginalFilename.
347  // Candidates with extensions matching PreferLanguage will be chosen over
348  // others (unless it's TY_INVALID, or all candidates are bad).
349  StringRef chooseProxy(StringRef OriginalFilename,
350  types::ID PreferLanguage) const {
351  assert(!empty() && "need at least one candidate!");
352  std::string Filename = OriginalFilename.lower();
353  auto Candidates = scoreCandidates(Filename);
354  std::pair<size_t, int> Best =
355  pickWinner(Candidates, Filename, PreferLanguage);
356 
357  DEBUG_WITH_TYPE(
358  "interpolate",
359  llvm::dbgs() << "interpolate: chose " << OriginalPaths[Best.first]
360  << " as proxy for " << OriginalFilename << " preferring "
361  << (PreferLanguage == types::TY_INVALID
362  ? "none"
363  : types::getTypeName(PreferLanguage))
364  << " score=" << Best.second << "\n");
365  return OriginalPaths[Best.first];
366  }
367 
368 private:
369  using SubstringAndIndex = std::pair<StringRef, size_t>;
370  // Directory matching parameters: we look at the last two segments of the
371  // parent directory (usually the semantically significant ones in practice).
372  // We search only the last four of each candidate (for efficiency).
373  constexpr static int DirectorySegmentsIndexed = 4;
374  constexpr static int DirectorySegmentsQueried = 2;
375  constexpr static int ShortDirectorySegment = 1; // Only look at longer names.
376 
377  // Award points to candidate entries that should be considered for the file.
378  // Returned keys are indexes into paths, and the values are (nonzero) scores.
379  DenseMap<size_t, int> scoreCandidates(StringRef Filename) const {
380  // Decompose Filename into the parts we care about.
381  // /some/path/complicated/project/Interesting.h
382  // [-prefix--][---dir---] [-dir-] [--stem---]
383  StringRef Stem = sys::path::stem(Filename);
385  llvm::StringRef Prefix;
386  auto Dir = ++sys::path::rbegin(Filename),
387  DirEnd = sys::path::rend(Filename);
388  for (int I = 0; I < DirectorySegmentsQueried && Dir != DirEnd; ++I, ++Dir) {
389  if (Dir->size() > ShortDirectorySegment)
390  Dirs.push_back(*Dir);
391  Prefix = Filename.substr(0, Dir - DirEnd);
392  }
393 
394  // Now award points based on lookups into our various indexes.
395  DenseMap<size_t, int> Candidates; // Index -> score.
396  auto Award = [&](int Points, ArrayRef<SubstringAndIndex> Range) {
397  for (const auto &Entry : Range)
398  Candidates[Entry.second] += Points;
399  };
400  // Award one point if the file's basename is a prefix of the candidate,
401  // and another if it's an exact match (so exact matches get two points).
402  Award(1, indexLookup</*Prefix=*/true>(Stem, Stems));
403  Award(1, indexLookup</*Prefix=*/false>(Stem, Stems));
404  // For each of the last few directories in the Filename, award a point
405  // if it's present in the candidate.
406  for (StringRef Dir : Dirs)
407  Award(1, indexLookup</*Prefix=*/false>(Dir, Components));
408  // Award one more point if the whole rest of the path matches.
409  if (sys::path::root_directory(Prefix) != Prefix)
410  Award(1, indexLookup</*Prefix=*/true>(Prefix, Paths));
411  return Candidates;
412  }
413 
414  // Pick a single winner from the set of scored candidates.
415  // Returns (index, score).
416  std::pair<size_t, int> pickWinner(const DenseMap<size_t, int> &Candidates,
417  StringRef Filename,
418  types::ID PreferredLanguage) const {
419  struct ScoredCandidate {
420  size_t Index;
421  bool Preferred;
422  int Points;
423  size_t PrefixLength;
424  };
425  // Choose the best candidate by (preferred, points, prefix length, alpha).
426  ScoredCandidate Best = {size_t(-1), false, 0, 0};
427  for (const auto &Candidate : Candidates) {
428  ScoredCandidate S;
429  S.Index = Candidate.first;
430  S.Preferred = PreferredLanguage == types::TY_INVALID ||
431  PreferredLanguage == Types[S.Index];
432  S.Points = Candidate.second;
433  if (!S.Preferred && Best.Preferred)
434  continue;
435  if (S.Preferred == Best.Preferred) {
436  if (S.Points < Best.Points)
437  continue;
438  if (S.Points == Best.Points) {
439  S.PrefixLength = matchingPrefix(Filename, Paths[S.Index].first);
440  if (S.PrefixLength < Best.PrefixLength)
441  continue;
442  // hidden heuristics should at least be deterministic!
443  if (S.PrefixLength == Best.PrefixLength)
444  if (S.Index > Best.Index)
445  continue;
446  }
447  }
448  // PrefixLength was only set above if actually needed for a tiebreak.
449  // But it definitely needs to be set to break ties in the future.
450  S.PrefixLength = matchingPrefix(Filename, Paths[S.Index].first);
451  Best = S;
452  }
453  // Edge case: no candidate got any points.
454  // We ignore PreferredLanguage at this point (not ideal).
455  if (Best.Index == size_t(-1))
456  return {longestMatch(Filename, Paths).second, 0};
457  return {Best.Index, Best.Points};
458  }
459 
460  // Returns the range within a sorted index that compares equal to Key.
461  // If Prefix is true, it's instead the range starting with Key.
462  template <bool Prefix>
464  indexLookup(StringRef Key, ArrayRef<SubstringAndIndex> Idx) const {
465  // Use pointers as iteratiors to ease conversion of result to ArrayRef.
466  auto Range = std::equal_range(Idx.data(), Idx.data() + Idx.size(), Key,
467  Less<Prefix>());
468  return {Range.first, Range.second};
469  }
470 
471  // Performs a point lookup into a nonempty index, returning a longest match.
472  SubstringAndIndex longestMatch(StringRef Key,
473  ArrayRef<SubstringAndIndex> Idx) const {
474  assert(!Idx.empty());
475  // Longest substring match will be adjacent to a direct lookup.
476  auto It =
477  std::lower_bound(Idx.begin(), Idx.end(), SubstringAndIndex{Key, 0});
478  if (It == Idx.begin())
479  return *It;
480  if (It == Idx.end())
481  return *--It;
482  // Have to choose between It and It-1
483  size_t Prefix = matchingPrefix(Key, It->first);
484  size_t PrevPrefix = matchingPrefix(Key, (It - 1)->first);
485  return Prefix > PrevPrefix ? *It : *--It;
486  }
487 
488  // Original paths, everything else is in lowercase.
489  std::vector<std::string> OriginalPaths;
490  BumpPtrAllocator Arena;
491  StringSaver Strings;
492  // Indexes of candidates by certain substrings.
493  // String is lowercase and sorted, index points into OriginalPaths.
494  std::vector<SubstringAndIndex> Paths; // Full path.
495  // Lang types obtained by guessing on the corresponding path. I-th element is
496  // a type for the I-th path.
497  std::vector<types::ID> Types;
498  std::vector<SubstringAndIndex> Stems; // Basename, without extension.
499  std::vector<SubstringAndIndex> Components; // Last path components.
500 };
501 
502 // The actual CompilationDatabase wrapper delegates to its inner database.
503 // If no match, looks up a proxy file in FileIndex and transfers its
504 // command to the requested file.
505 class InterpolatingCompilationDatabase : public CompilationDatabase {
506 public:
507  InterpolatingCompilationDatabase(std::unique_ptr<CompilationDatabase> Inner)
508  : Inner(std::move(Inner)), Index(this->Inner->getAllFiles()) {}
509 
510  std::vector<CompileCommand>
511  getCompileCommands(StringRef Filename) const override {
512  auto Known = Inner->getCompileCommands(Filename);
513  if (Index.empty() || !Known.empty())
514  return Known;
515  bool TypeCertain;
516  auto Lang = guessType(Filename, &TypeCertain);
517  if (!TypeCertain)
518  Lang = types::TY_INVALID;
519  auto ProxyCommands =
520  Inner->getCompileCommands(Index.chooseProxy(Filename, foldType(Lang)));
521  if (ProxyCommands.empty())
522  return {};
523  return {TransferableCommand(ProxyCommands[0]).transferTo(Filename)};
524  }
525 
526  std::vector<std::string> getAllFiles() const override {
527  return Inner->getAllFiles();
528  }
529 
530  std::vector<CompileCommand> getAllCompileCommands() const override {
531  return Inner->getAllCompileCommands();
532  }
533 
534 private:
535  std::unique_ptr<CompilationDatabase> Inner;
536  FileIndex Index;
537 };
538 
539 } // namespace
540 
541 std::unique_ptr<CompilationDatabase>
542 inferMissingCompileCommands(std::unique_ptr<CompilationDatabase> Inner) {
543  return llvm::make_unique<InterpolatingCompilationDatabase>(std::move(Inner));
544 }
545 
546 } // namespace tooling
547 } // namespace clang
__SIZE_TYPE__ size_t
The unsigned integer type of the result of the sizeof operator.
Definition: opencl-c.h:68
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:30
static const LangStandard & getLangStandardForKind(Kind K)
std::string getName(ArrayRef< StringRef > Parts) const
Get the platform-specific name separator.
Definition: Format.h:2072
Languages that the frontend can parse and compile.
CompileCommand Cmd
std::unique_ptr< llvm::opt::OptTable > createDriverOptTable()
return Out str()
StringRef Filename
Definition: Format.cpp:1629
ID lookupHeaderTypeForSourceType(ID Id)
Lookup header file input type that corresponds to given source file type (used for clang-cl emulation...
Definition: Types.cpp:310
const char * getTypeName(ID Id)
getTypeName - Return the name of the type for Id.
Definition: Types.cpp:39
std::unique_ptr< CompilationDatabase > inferMissingCompileCommands(std::unique_ptr< CompilationDatabase >)
Returns a wrapped CompilationDatabase that defers to the provided one, but getCompileCommands() will ...
Optional< types::ID > Type
Dataflow Directional Tag Classes.
Language
The language for the input, used to select and validate the language standard and possible actions...
ID lookupTypeForExtension(llvm::StringRef Ext)
lookupTypeForExtension - Lookup the type to use for the file extension Ext.
Definition: Types.cpp:195
bool onlyPrecompileType(ID Id)
onlyPrecompileType - Should this type only be precompiled.
Definition: Types.cpp:76
#define LANGSTANDARD(id, name, lang,...)
__DEVICE__ int min(int __a, int __b)
ID lookupTypeForTypeSpecifier(const char *Name)
lookupTypeForTypSpecifier - Lookup the type to use for a user specified type name.
Definition: Types.cpp:256
A node that&#39;s not selected.
LangStandard::Kind Std