1//===--- MacroExpansion.cpp - Top level Macro Expansion -------------------===//
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// This file implements the top level handling of macro expansion for the
11// preprocessor.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/Lex/Preprocessor.h"
16#include "clang/Basic/Attributes.h"
17#include "clang/Basic/FileManager.h"
18#include "clang/Basic/SourceManager.h"
19#include "clang/Basic/TargetInfo.h"
20#include "clang/Lex/CodeCompletionHandler.h"
21#include "clang/Lex/ExternalPreprocessorSource.h"
22#include "clang/Lex/LexDiagnostic.h"
23#include "clang/Lex/MacroArgs.h"
24#include "clang/Lex/MacroInfo.h"
25#include "llvm/ADT/STLExtras.h"
26#include "llvm/ADT/SmallString.h"
27#include "llvm/ADT/StringSwitch.h"
28#include "llvm/Config/llvm-config.h"
29#include "llvm/Support/ErrorHandling.h"
30#include "llvm/Support/Format.h"
31#include "llvm/Support/raw_ostream.h"
32#include <cstdio>
33#include <ctime>
34using namespace clang;
35
36MacroDirective *
37Preprocessor::getMacroDirectiveHistory(const IdentifierInfo *II) const {
38  assert(II->hadMacroDefinition() && "Identifier has not been not a macro!");
39
40  macro_iterator Pos = Macros.find(II);
41  assert(Pos != Macros.end() && "Identifier macro info is missing!");
42  return Pos->second;
43}
44
45void Preprocessor::appendMacroDirective(IdentifierInfo *II, MacroDirective *MD){
46  assert(MD && "MacroDirective should be non-zero!");
47  assert(!MD->getPrevious() && "Already attached to a MacroDirective history.");
48
49  MacroDirective *&StoredMD = Macros[II];
50  MD->setPrevious(StoredMD);
51  StoredMD = MD;
52  II->setHasMacroDefinition(MD->isDefined());
53  bool isImportedMacro = isa<DefMacroDirective>(MD) &&
54                         cast<DefMacroDirective>(MD)->isImported();
55  if (II->isFromAST() && !isImportedMacro)
56    II->setChangedSinceDeserialization();
57}
58
59void Preprocessor::setLoadedMacroDirective(IdentifierInfo *II,
60                                           MacroDirective *MD) {
61  assert(II && MD);
62  MacroDirective *&StoredMD = Macros[II];
63  assert(!StoredMD &&
64         "the macro history was modified before initializing it from a pch");
65  StoredMD = MD;
66  // Setup the identifier as having associated macro history.
67  II->setHasMacroDefinition(true);
68  if (!MD->isDefined())
69    II->setHasMacroDefinition(false);
70}
71
72/// RegisterBuiltinMacro - Register the specified identifier in the identifier
73/// table and mark it as a builtin macro to be expanded.
74static IdentifierInfo *RegisterBuiltinMacro(Preprocessor &PP, const char *Name){
75  // Get the identifier.
76  IdentifierInfo *Id = PP.getIdentifierInfo(Name);
77
78  // Mark it as being a macro that is builtin.
79  MacroInfo *MI = PP.AllocateMacroInfo(SourceLocation());
80  MI->setIsBuiltinMacro();
81  PP.appendDefMacroDirective(Id, MI);
82  return Id;
83}
84
85
86/// RegisterBuiltinMacros - Register builtin macros, such as __LINE__ with the
87/// identifier table.
88void Preprocessor::RegisterBuiltinMacros() {
89  Ident__LINE__ = RegisterBuiltinMacro(*this, "__LINE__");
90  Ident__FILE__ = RegisterBuiltinMacro(*this, "__FILE__");
91  Ident__DATE__ = RegisterBuiltinMacro(*this, "__DATE__");
92  Ident__TIME__ = RegisterBuiltinMacro(*this, "__TIME__");
93  Ident__COUNTER__ = RegisterBuiltinMacro(*this, "__COUNTER__");
94  Ident_Pragma  = RegisterBuiltinMacro(*this, "_Pragma");
95
96  // GCC Extensions.
97  Ident__BASE_FILE__     = RegisterBuiltinMacro(*this, "__BASE_FILE__");
98  Ident__INCLUDE_LEVEL__ = RegisterBuiltinMacro(*this, "__INCLUDE_LEVEL__");
99  Ident__TIMESTAMP__     = RegisterBuiltinMacro(*this, "__TIMESTAMP__");
100
101  // Microsoft Extensions.
102  if (LangOpts.MicrosoftExt) {
103    Ident__identifier = RegisterBuiltinMacro(*this, "__identifier");
104    Ident__pragma = RegisterBuiltinMacro(*this, "__pragma");
105  } else {
106    Ident__identifier = nullptr;
107    Ident__pragma = nullptr;
108  }
109
110  // Clang Extensions.
111  Ident__has_feature      = RegisterBuiltinMacro(*this, "__has_feature");
112  Ident__has_extension    = RegisterBuiltinMacro(*this, "__has_extension");
113  Ident__has_builtin      = RegisterBuiltinMacro(*this, "__has_builtin");
114  Ident__has_attribute    = RegisterBuiltinMacro(*this, "__has_attribute");
115  Ident__has_include      = RegisterBuiltinMacro(*this, "__has_include");
116  Ident__has_include_next = RegisterBuiltinMacro(*this, "__has_include_next");
117  Ident__has_warning      = RegisterBuiltinMacro(*this, "__has_warning");
118  Ident__is_identifier    = RegisterBuiltinMacro(*this, "__is_identifier");
119
120  // Modules.
121  if (LangOpts.Modules) {
122    Ident__building_module  = RegisterBuiltinMacro(*this, "__building_module");
123
124    // __MODULE__
125    if (!LangOpts.CurrentModule.empty())
126      Ident__MODULE__ = RegisterBuiltinMacro(*this, "__MODULE__");
127    else
128      Ident__MODULE__ = nullptr;
129  } else {
130    Ident__building_module = nullptr;
131    Ident__MODULE__ = nullptr;
132  }
133}
134
135/// isTrivialSingleTokenExpansion - Return true if MI, which has a single token
136/// in its expansion, currently expands to that token literally.
137static bool isTrivialSingleTokenExpansion(const MacroInfo *MI,
138                                          const IdentifierInfo *MacroIdent,
139                                          Preprocessor &PP) {
140  IdentifierInfo *II = MI->getReplacementToken(0).getIdentifierInfo();
141
142  // If the token isn't an identifier, it's always literally expanded.
143  if (!II) return true;
144
145  // If the information about this identifier is out of date, update it from
146  // the external source.
147  if (II->isOutOfDate())
148    PP.getExternalSource()->updateOutOfDateIdentifier(*II);
149
150  // If the identifier is a macro, and if that macro is enabled, it may be
151  // expanded so it's not a trivial expansion.
152  if (II->hasMacroDefinition() && PP.getMacroInfo(II)->isEnabled() &&
153      // Fast expanding "#define X X" is ok, because X would be disabled.
154      II != MacroIdent)
155    return false;
156
157  // If this is an object-like macro invocation, it is safe to trivially expand
158  // it.
159  if (MI->isObjectLike()) return true;
160
161  // If this is a function-like macro invocation, it's safe to trivially expand
162  // as long as the identifier is not a macro argument.
163  for (MacroInfo::arg_iterator I = MI->arg_begin(), E = MI->arg_end();
164       I != E; ++I)
165    if (*I == II)
166      return false;   // Identifier is a macro argument.
167
168  return true;
169}
170
171
172/// isNextPPTokenLParen - Determine whether the next preprocessor token to be
173/// lexed is a '('.  If so, consume the token and return true, if not, this
174/// method should have no observable side-effect on the lexed tokens.
175bool Preprocessor::isNextPPTokenLParen() {
176  // Do some quick tests for rejection cases.
177  unsigned Val;
178  if (CurLexer)
179    Val = CurLexer->isNextPPTokenLParen();
180  else if (CurPTHLexer)
181    Val = CurPTHLexer->isNextPPTokenLParen();
182  else
183    Val = CurTokenLexer->isNextTokenLParen();
184
185  if (Val == 2) {
186    // We have run off the end.  If it's a source file we don't
187    // examine enclosing ones (C99 5.1.1.2p4).  Otherwise walk up the
188    // macro stack.
189    if (CurPPLexer)
190      return false;
191    for (unsigned i = IncludeMacroStack.size(); i != 0; --i) {
192      IncludeStackInfo &Entry = IncludeMacroStack[i-1];
193      if (Entry.TheLexer)
194        Val = Entry.TheLexer->isNextPPTokenLParen();
195      else if (Entry.ThePTHLexer)
196        Val = Entry.ThePTHLexer->isNextPPTokenLParen();
197      else
198        Val = Entry.TheTokenLexer->isNextTokenLParen();
199
200      if (Val != 2)
201        break;
202
203      // Ran off the end of a source file?
204      if (Entry.ThePPLexer)
205        return false;
206    }
207  }
208
209  // Okay, if we know that the token is a '(', lex it and return.  Otherwise we
210  // have found something that isn't a '(' or we found the end of the
211  // translation unit.  In either case, return false.
212  return Val == 1;
213}
214
215/// HandleMacroExpandedIdentifier - If an identifier token is read that is to be
216/// expanded as a macro, handle it and return the next token as 'Identifier'.
217bool Preprocessor::HandleMacroExpandedIdentifier(Token &Identifier,
218                                                 MacroDirective *MD) {
219  MacroDirective::DefInfo Def = MD->getDefinition();
220  assert(Def.isValid());
221  MacroInfo *MI = Def.getMacroInfo();
222
223  // If this is a macro expansion in the "#if !defined(x)" line for the file,
224  // then the macro could expand to different things in other contexts, we need
225  // to disable the optimization in this case.
226  if (CurPPLexer) CurPPLexer->MIOpt.ExpandedMacro();
227
228  // If this is a builtin macro, like __LINE__ or _Pragma, handle it specially.
229  if (MI->isBuiltinMacro()) {
230    if (Callbacks) Callbacks->MacroExpands(Identifier, MD,
231                                           Identifier.getLocation(),
232                                           /*Args=*/nullptr);
233    ExpandBuiltinMacro(Identifier);
234    return true;
235  }
236
237  /// Args - If this is a function-like macro expansion, this contains,
238  /// for each macro argument, the list of tokens that were provided to the
239  /// invocation.
240  MacroArgs *Args = nullptr;
241
242  // Remember where the end of the expansion occurred.  For an object-like
243  // macro, this is the identifier.  For a function-like macro, this is the ')'.
244  SourceLocation ExpansionEnd = Identifier.getLocation();
245
246  // If this is a function-like macro, read the arguments.
247  if (MI->isFunctionLike()) {
248    // Remember that we are now parsing the arguments to a macro invocation.
249    // Preprocessor directives used inside macro arguments are not portable, and
250    // this enables the warning.
251    InMacroArgs = true;
252    Args = ReadFunctionLikeMacroArgs(Identifier, MI, ExpansionEnd);
253
254    // Finished parsing args.
255    InMacroArgs = false;
256
257    // If there was an error parsing the arguments, bail out.
258    if (!Args) return true;
259
260    ++NumFnMacroExpanded;
261  } else {
262    ++NumMacroExpanded;
263  }
264
265  // Notice that this macro has been used.
266  markMacroAsUsed(MI);
267
268  // Remember where the token is expanded.
269  SourceLocation ExpandLoc = Identifier.getLocation();
270  SourceRange ExpansionRange(ExpandLoc, ExpansionEnd);
271
272  if (Callbacks) {
273    if (InMacroArgs) {
274      // We can have macro expansion inside a conditional directive while
275      // reading the function macro arguments. To ensure, in that case, that
276      // MacroExpands callbacks still happen in source order, queue this
277      // callback to have it happen after the function macro callback.
278      DelayedMacroExpandsCallbacks.push_back(
279                              MacroExpandsInfo(Identifier, MD, ExpansionRange));
280    } else {
281      Callbacks->MacroExpands(Identifier, MD, ExpansionRange, Args);
282      if (!DelayedMacroExpandsCallbacks.empty()) {
283        for (unsigned i=0, e = DelayedMacroExpandsCallbacks.size(); i!=e; ++i) {
284          MacroExpandsInfo &Info = DelayedMacroExpandsCallbacks[i];
285          // FIXME: We lose macro args info with delayed callback.
286          Callbacks->MacroExpands(Info.Tok, Info.MD, Info.Range,
287                                  /*Args=*/nullptr);
288        }
289        DelayedMacroExpandsCallbacks.clear();
290      }
291    }
292  }
293
294  // If the macro definition is ambiguous, complain.
295  if (Def.getDirective()->isAmbiguous()) {
296    Diag(Identifier, diag::warn_pp_ambiguous_macro)
297      << Identifier.getIdentifierInfo();
298    Diag(MI->getDefinitionLoc(), diag::note_pp_ambiguous_macro_chosen)
299      << Identifier.getIdentifierInfo();
300    for (MacroDirective::DefInfo PrevDef = Def.getPreviousDefinition();
301         PrevDef && !PrevDef.isUndefined();
302         PrevDef = PrevDef.getPreviousDefinition()) {
303      Diag(PrevDef.getMacroInfo()->getDefinitionLoc(),
304           diag::note_pp_ambiguous_macro_other)
305        << Identifier.getIdentifierInfo();
306      if (!PrevDef.getDirective()->isAmbiguous())
307        break;
308    }
309  }
310
311  // If we started lexing a macro, enter the macro expansion body.
312
313  // If this macro expands to no tokens, don't bother to push it onto the
314  // expansion stack, only to take it right back off.
315  if (MI->getNumTokens() == 0) {
316    // No need for arg info.
317    if (Args) Args->destroy(*this);
318
319    // Propagate whitespace info as if we had pushed, then popped,
320    // a macro context.
321    Identifier.setFlag(Token::LeadingEmptyMacro);
322    PropagateLineStartLeadingSpaceInfo(Identifier);
323    ++NumFastMacroExpanded;
324    return false;
325  } else if (MI->getNumTokens() == 1 &&
326             isTrivialSingleTokenExpansion(MI, Identifier.getIdentifierInfo(),
327                                           *this)) {
328    // Otherwise, if this macro expands into a single trivially-expanded
329    // token: expand it now.  This handles common cases like
330    // "#define VAL 42".
331
332    // No need for arg info.
333    if (Args) Args->destroy(*this);
334
335    // Propagate the isAtStartOfLine/hasLeadingSpace markers of the macro
336    // identifier to the expanded token.
337    bool isAtStartOfLine = Identifier.isAtStartOfLine();
338    bool hasLeadingSpace = Identifier.hasLeadingSpace();
339
340    // Replace the result token.
341    Identifier = MI->getReplacementToken(0);
342
343    // Restore the StartOfLine/LeadingSpace markers.
344    Identifier.setFlagValue(Token::StartOfLine , isAtStartOfLine);
345    Identifier.setFlagValue(Token::LeadingSpace, hasLeadingSpace);
346
347    // Update the tokens location to include both its expansion and physical
348    // locations.
349    SourceLocation Loc =
350      SourceMgr.createExpansionLoc(Identifier.getLocation(), ExpandLoc,
351                                   ExpansionEnd,Identifier.getLength());
352    Identifier.setLocation(Loc);
353
354    // If this is a disabled macro or #define X X, we must mark the result as
355    // unexpandable.
356    if (IdentifierInfo *NewII = Identifier.getIdentifierInfo()) {
357      if (MacroInfo *NewMI = getMacroInfo(NewII))
358        if (!NewMI->isEnabled() || NewMI == MI) {
359          Identifier.setFlag(Token::DisableExpand);
360          // Don't warn for "#define X X" like "#define bool bool" from
361          // stdbool.h.
362          if (NewMI != MI || MI->isFunctionLike())
363            Diag(Identifier, diag::pp_disabled_macro_expansion);
364        }
365    }
366
367    // Since this is not an identifier token, it can't be macro expanded, so
368    // we're done.
369    ++NumFastMacroExpanded;
370    return true;
371  }
372
373  // Start expanding the macro.
374  EnterMacro(Identifier, ExpansionEnd, MI, Args);
375  return false;
376}
377
378enum Bracket {
379  Brace,
380  Paren
381};
382
383/// CheckMatchedBrackets - Returns true if the braces and parentheses in the
384/// token vector are properly nested.
385static bool CheckMatchedBrackets(const SmallVectorImpl<Token> &Tokens) {
386  SmallVector<Bracket, 8> Brackets;
387  for (SmallVectorImpl<Token>::const_iterator I = Tokens.begin(),
388                                              E = Tokens.end();
389       I != E; ++I) {
390    if (I->is(tok::l_paren)) {
391      Brackets.push_back(Paren);
392    } else if (I->is(tok::r_paren)) {
393      if (Brackets.empty() || Brackets.back() == Brace)
394        return false;
395      Brackets.pop_back();
396    } else if (I->is(tok::l_brace)) {
397      Brackets.push_back(Brace);
398    } else if (I->is(tok::r_brace)) {
399      if (Brackets.empty() || Brackets.back() == Paren)
400        return false;
401      Brackets.pop_back();
402    }
403  }
404  if (!Brackets.empty())
405    return false;
406  return true;
407}
408
409/// GenerateNewArgTokens - Returns true if OldTokens can be converted to a new
410/// vector of tokens in NewTokens.  The new number of arguments will be placed
411/// in NumArgs and the ranges which need to surrounded in parentheses will be
412/// in ParenHints.
413/// Returns false if the token stream cannot be changed.  If this is because
414/// of an initializer list starting a macro argument, the range of those
415/// initializer lists will be place in InitLists.
416static bool GenerateNewArgTokens(Preprocessor &PP,
417                                 SmallVectorImpl<Token> &OldTokens,
418                                 SmallVectorImpl<Token> &NewTokens,
419                                 unsigned &NumArgs,
420                                 SmallVectorImpl<SourceRange> &ParenHints,
421                                 SmallVectorImpl<SourceRange> &InitLists) {
422  if (!CheckMatchedBrackets(OldTokens))
423    return false;
424
425  // Once it is known that the brackets are matched, only a simple count of the
426  // braces is needed.
427  unsigned Braces = 0;
428
429  // First token of a new macro argument.
430  SmallVectorImpl<Token>::iterator ArgStartIterator = OldTokens.begin();
431
432  // First closing brace in a new macro argument.  Used to generate
433  // SourceRanges for InitLists.
434  SmallVectorImpl<Token>::iterator ClosingBrace = OldTokens.end();
435  NumArgs = 0;
436  Token TempToken;
437  // Set to true when a macro separator token is found inside a braced list.
438  // If true, the fixed argument spans multiple old arguments and ParenHints
439  // will be updated.
440  bool FoundSeparatorToken = false;
441  for (SmallVectorImpl<Token>::iterator I = OldTokens.begin(),
442                                        E = OldTokens.end();
443       I != E; ++I) {
444    if (I->is(tok::l_brace)) {
445      ++Braces;
446    } else if (I->is(tok::r_brace)) {
447      --Braces;
448      if (Braces == 0 && ClosingBrace == E && FoundSeparatorToken)
449        ClosingBrace = I;
450    } else if (I->is(tok::eof)) {
451      // EOF token is used to separate macro arguments
452      if (Braces != 0) {
453        // Assume comma separator is actually braced list separator and change
454        // it back to a comma.
455        FoundSeparatorToken = true;
456        I->setKind(tok::comma);
457        I->setLength(1);
458      } else { // Braces == 0
459        // Separator token still separates arguments.
460        ++NumArgs;
461
462        // If the argument starts with a brace, it can't be fixed with
463        // parentheses.  A different diagnostic will be given.
464        if (FoundSeparatorToken && ArgStartIterator->is(tok::l_brace)) {
465          InitLists.push_back(
466              SourceRange(ArgStartIterator->getLocation(),
467                          PP.getLocForEndOfToken(ClosingBrace->getLocation())));
468          ClosingBrace = E;
469        }
470
471        // Add left paren
472        if (FoundSeparatorToken) {
473          TempToken.startToken();
474          TempToken.setKind(tok::l_paren);
475          TempToken.setLocation(ArgStartIterator->getLocation());
476          TempToken.setLength(0);
477          NewTokens.push_back(TempToken);
478        }
479
480        // Copy over argument tokens
481        NewTokens.insert(NewTokens.end(), ArgStartIterator, I);
482
483        // Add right paren and store the paren locations in ParenHints
484        if (FoundSeparatorToken) {
485          SourceLocation Loc = PP.getLocForEndOfToken((I - 1)->getLocation());
486          TempToken.startToken();
487          TempToken.setKind(tok::r_paren);
488          TempToken.setLocation(Loc);
489          TempToken.setLength(0);
490          NewTokens.push_back(TempToken);
491          ParenHints.push_back(SourceRange(ArgStartIterator->getLocation(),
492                                           Loc));
493        }
494
495        // Copy separator token
496        NewTokens.push_back(*I);
497
498        // Reset values
499        ArgStartIterator = I + 1;
500        FoundSeparatorToken = false;
501      }
502    }
503  }
504
505  return !ParenHints.empty() && InitLists.empty();
506}
507
508/// ReadFunctionLikeMacroArgs - After reading "MACRO" and knowing that the next
509/// token is the '(' of the macro, this method is invoked to read all of the
510/// actual arguments specified for the macro invocation.  This returns null on
511/// error.
512MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
513                                                   MacroInfo *MI,
514                                                   SourceLocation &MacroEnd) {
515  // The number of fixed arguments to parse.
516  unsigned NumFixedArgsLeft = MI->getNumArgs();
517  bool isVariadic = MI->isVariadic();
518
519  // Outer loop, while there are more arguments, keep reading them.
520  Token Tok;
521
522  // Read arguments as unexpanded tokens.  This avoids issues, e.g., where
523  // an argument value in a macro could expand to ',' or '(' or ')'.
524  LexUnexpandedToken(Tok);
525  assert(Tok.is(tok::l_paren) && "Error computing l-paren-ness?");
526
527  // ArgTokens - Build up a list of tokens that make up each argument.  Each
528  // argument is separated by an EOF token.  Use a SmallVector so we can avoid
529  // heap allocations in the common case.
530  SmallVector<Token, 64> ArgTokens;
531  bool ContainsCodeCompletionTok = false;
532
533  SourceLocation TooManyArgsLoc;
534
535  unsigned NumActuals = 0;
536  while (Tok.isNot(tok::r_paren)) {
537    if (ContainsCodeCompletionTok && (Tok.is(tok::eof) || Tok.is(tok::eod)))
538      break;
539
540    assert((Tok.is(tok::l_paren) || Tok.is(tok::comma)) &&
541           "only expect argument separators here");
542
543    unsigned ArgTokenStart = ArgTokens.size();
544    SourceLocation ArgStartLoc = Tok.getLocation();
545
546    // C99 6.10.3p11: Keep track of the number of l_parens we have seen.  Note
547    // that we already consumed the first one.
548    unsigned NumParens = 0;
549
550    while (1) {
551      // Read arguments as unexpanded tokens.  This avoids issues, e.g., where
552      // an argument value in a macro could expand to ',' or '(' or ')'.
553      LexUnexpandedToken(Tok);
554
555      if (Tok.is(tok::eof) || Tok.is(tok::eod)) { // "#if f(<eof>" & "#if f(\n"
556        if (!ContainsCodeCompletionTok) {
557          Diag(MacroName, diag::err_unterm_macro_invoc);
558          Diag(MI->getDefinitionLoc(), diag::note_macro_here)
559            << MacroName.getIdentifierInfo();
560          // Do not lose the EOF/EOD.  Return it to the client.
561          MacroName = Tok;
562          return nullptr;
563        } else {
564          // Do not lose the EOF/EOD.
565          Token *Toks = new Token[1];
566          Toks[0] = Tok;
567          EnterTokenStream(Toks, 1, true, true);
568          break;
569        }
570      } else if (Tok.is(tok::r_paren)) {
571        // If we found the ) token, the macro arg list is done.
572        if (NumParens-- == 0) {
573          MacroEnd = Tok.getLocation();
574          break;
575        }
576      } else if (Tok.is(tok::l_paren)) {
577        ++NumParens;
578      } else if (Tok.is(tok::comma) && NumParens == 0 &&
579                 !(Tok.getFlags() & Token::IgnoredComma)) {
580        // In Microsoft-compatibility mode, single commas from nested macro
581        // expansions should not be considered as argument separators. We test
582        // for this with the IgnoredComma token flag above.
583
584        // Comma ends this argument if there are more fixed arguments expected.
585        // However, if this is a variadic macro, and this is part of the
586        // variadic part, then the comma is just an argument token.
587        if (!isVariadic) break;
588        if (NumFixedArgsLeft > 1)
589          break;
590      } else if (Tok.is(tok::comment) && !KeepMacroComments) {
591        // If this is a comment token in the argument list and we're just in
592        // -C mode (not -CC mode), discard the comment.
593        continue;
594      } else if (Tok.getIdentifierInfo() != nullptr) {
595        // Reading macro arguments can cause macros that we are currently
596        // expanding from to be popped off the expansion stack.  Doing so causes
597        // them to be reenabled for expansion.  Here we record whether any
598        // identifiers we lex as macro arguments correspond to disabled macros.
599        // If so, we mark the token as noexpand.  This is a subtle aspect of
600        // C99 6.10.3.4p2.
601        if (MacroInfo *MI = getMacroInfo(Tok.getIdentifierInfo()))
602          if (!MI->isEnabled())
603            Tok.setFlag(Token::DisableExpand);
604      } else if (Tok.is(tok::code_completion)) {
605        ContainsCodeCompletionTok = true;
606        if (CodeComplete)
607          CodeComplete->CodeCompleteMacroArgument(MacroName.getIdentifierInfo(),
608                                                  MI, NumActuals);
609        // Don't mark that we reached the code-completion point because the
610        // parser is going to handle the token and there will be another
611        // code-completion callback.
612      }
613
614      ArgTokens.push_back(Tok);
615    }
616
617    // If this was an empty argument list foo(), don't add this as an empty
618    // argument.
619    if (ArgTokens.empty() && Tok.getKind() == tok::r_paren)
620      break;
621
622    // If this is not a variadic macro, and too many args were specified, emit
623    // an error.
624    if (!isVariadic && NumFixedArgsLeft == 0 && TooManyArgsLoc.isInvalid()) {
625      if (ArgTokens.size() != ArgTokenStart)
626        TooManyArgsLoc = ArgTokens[ArgTokenStart].getLocation();
627      else
628        TooManyArgsLoc = ArgStartLoc;
629    }
630
631    // Empty arguments are standard in C99 and C++0x, and are supported as an
632    // extension in other modes.
633    if (ArgTokens.size() == ArgTokenStart && !LangOpts.C99)
634      Diag(Tok, LangOpts.CPlusPlus11 ?
635           diag::warn_cxx98_compat_empty_fnmacro_arg :
636           diag::ext_empty_fnmacro_arg);
637
638    // Add a marker EOF token to the end of the token list for this argument.
639    Token EOFTok;
640    EOFTok.startToken();
641    EOFTok.setKind(tok::eof);
642    EOFTok.setLocation(Tok.getLocation());
643    EOFTok.setLength(0);
644    ArgTokens.push_back(EOFTok);
645    ++NumActuals;
646    if (!ContainsCodeCompletionTok && NumFixedArgsLeft != 0)
647      --NumFixedArgsLeft;
648  }
649
650  // Okay, we either found the r_paren.  Check to see if we parsed too few
651  // arguments.
652  unsigned MinArgsExpected = MI->getNumArgs();
653
654  // If this is not a variadic macro, and too many args were specified, emit
655  // an error.
656  if (!isVariadic && NumActuals > MinArgsExpected &&
657      !ContainsCodeCompletionTok) {
658    // Emit the diagnostic at the macro name in case there is a missing ).
659    // Emitting it at the , could be far away from the macro name.
660    Diag(TooManyArgsLoc, diag::err_too_many_args_in_macro_invoc);
661    Diag(MI->getDefinitionLoc(), diag::note_macro_here)
662      << MacroName.getIdentifierInfo();
663
664    // Commas from braced initializer lists will be treated as argument
665    // separators inside macros.  Attempt to correct for this with parentheses.
666    // TODO: See if this can be generalized to angle brackets for templates
667    // inside macro arguments.
668
669    SmallVector<Token, 4> FixedArgTokens;
670    unsigned FixedNumArgs = 0;
671    SmallVector<SourceRange, 4> ParenHints, InitLists;
672    if (!GenerateNewArgTokens(*this, ArgTokens, FixedArgTokens, FixedNumArgs,
673                              ParenHints, InitLists)) {
674      if (!InitLists.empty()) {
675        DiagnosticBuilder DB =
676            Diag(MacroName,
677                 diag::note_init_list_at_beginning_of_macro_argument);
678        for (const SourceRange &Range : InitLists)
679          DB << Range;
680      }
681      return nullptr;
682    }
683    if (FixedNumArgs != MinArgsExpected)
684      return nullptr;
685
686    DiagnosticBuilder DB = Diag(MacroName, diag::note_suggest_parens_for_macro);
687    for (const SourceRange &ParenLocation : ParenHints) {
688      DB << FixItHint::CreateInsertion(ParenLocation.getBegin(), "(");
689      DB << FixItHint::CreateInsertion(ParenLocation.getEnd(), ")");
690    }
691    ArgTokens.swap(FixedArgTokens);
692    NumActuals = FixedNumArgs;
693  }
694
695  // See MacroArgs instance var for description of this.
696  bool isVarargsElided = false;
697
698  if (ContainsCodeCompletionTok) {
699    // Recover from not-fully-formed macro invocation during code-completion.
700    Token EOFTok;
701    EOFTok.startToken();
702    EOFTok.setKind(tok::eof);
703    EOFTok.setLocation(Tok.getLocation());
704    EOFTok.setLength(0);
705    for (; NumActuals < MinArgsExpected; ++NumActuals)
706      ArgTokens.push_back(EOFTok);
707  }
708
709  if (NumActuals < MinArgsExpected) {
710    // There are several cases where too few arguments is ok, handle them now.
711    if (NumActuals == 0 && MinArgsExpected == 1) {
712      // #define A(X)  or  #define A(...)   ---> A()
713
714      // If there is exactly one argument, and that argument is missing,
715      // then we have an empty "()" argument empty list.  This is fine, even if
716      // the macro expects one argument (the argument is just empty).
717      isVarargsElided = MI->isVariadic();
718    } else if (MI->isVariadic() &&
719               (NumActuals+1 == MinArgsExpected ||  // A(x, ...) -> A(X)
720                (NumActuals == 0 && MinArgsExpected == 2))) {// A(x,...) -> A()
721      // Varargs where the named vararg parameter is missing: OK as extension.
722      //   #define A(x, ...)
723      //   A("blah")
724      //
725      // If the macro contains the comma pasting extension, the diagnostic
726      // is suppressed; we know we'll get another diagnostic later.
727      if (!MI->hasCommaPasting()) {
728        Diag(Tok, diag::ext_missing_varargs_arg);
729        Diag(MI->getDefinitionLoc(), diag::note_macro_here)
730          << MacroName.getIdentifierInfo();
731      }
732
733      // Remember this occurred, allowing us to elide the comma when used for
734      // cases like:
735      //   #define A(x, foo...) blah(a, ## foo)
736      //   #define B(x, ...) blah(a, ## __VA_ARGS__)
737      //   #define C(...) blah(a, ## __VA_ARGS__)
738      //  A(x) B(x) C()
739      isVarargsElided = true;
740    } else if (!ContainsCodeCompletionTok) {
741      // Otherwise, emit the error.
742      Diag(Tok, diag::err_too_few_args_in_macro_invoc);
743      Diag(MI->getDefinitionLoc(), diag::note_macro_here)
744        << MacroName.getIdentifierInfo();
745      return nullptr;
746    }
747
748    // Add a marker EOF token to the end of the token list for this argument.
749    SourceLocation EndLoc = Tok.getLocation();
750    Tok.startToken();
751    Tok.setKind(tok::eof);
752    Tok.setLocation(EndLoc);
753    Tok.setLength(0);
754    ArgTokens.push_back(Tok);
755
756    // If we expect two arguments, add both as empty.
757    if (NumActuals == 0 && MinArgsExpected == 2)
758      ArgTokens.push_back(Tok);
759
760  } else if (NumActuals > MinArgsExpected && !MI->isVariadic() &&
761             !ContainsCodeCompletionTok) {
762    // Emit the diagnostic at the macro name in case there is a missing ).
763    // Emitting it at the , could be far away from the macro name.
764    Diag(MacroName, diag::err_too_many_args_in_macro_invoc);
765    Diag(MI->getDefinitionLoc(), diag::note_macro_here)
766      << MacroName.getIdentifierInfo();
767    return nullptr;
768  }
769
770  return MacroArgs::create(MI, ArgTokens, isVarargsElided, *this);
771}
772
773/// \brief Keeps macro expanded tokens for TokenLexers.
774//
775/// Works like a stack; a TokenLexer adds the macro expanded tokens that is
776/// going to lex in the cache and when it finishes the tokens are removed
777/// from the end of the cache.
778Token *Preprocessor::cacheMacroExpandedTokens(TokenLexer *tokLexer,
779                                              ArrayRef<Token> tokens) {
780  assert(tokLexer);
781  if (tokens.empty())
782    return nullptr;
783
784  size_t newIndex = MacroExpandedTokens.size();
785  bool cacheNeedsToGrow = tokens.size() >
786                      MacroExpandedTokens.capacity()-MacroExpandedTokens.size();
787  MacroExpandedTokens.append(tokens.begin(), tokens.end());
788
789  if (cacheNeedsToGrow) {
790    // Go through all the TokenLexers whose 'Tokens' pointer points in the
791    // buffer and update the pointers to the (potential) new buffer array.
792    for (unsigned i = 0, e = MacroExpandingLexersStack.size(); i != e; ++i) {
793      TokenLexer *prevLexer;
794      size_t tokIndex;
795      std::tie(prevLexer, tokIndex) = MacroExpandingLexersStack[i];
796      prevLexer->Tokens = MacroExpandedTokens.data() + tokIndex;
797    }
798  }
799
800  MacroExpandingLexersStack.push_back(std::make_pair(tokLexer, newIndex));
801  return MacroExpandedTokens.data() + newIndex;
802}
803
804void Preprocessor::removeCachedMacroExpandedTokensOfLastLexer() {
805  assert(!MacroExpandingLexersStack.empty());
806  size_t tokIndex = MacroExpandingLexersStack.back().second;
807  assert(tokIndex < MacroExpandedTokens.size());
808  // Pop the cached macro expanded tokens from the end.
809  MacroExpandedTokens.resize(tokIndex);
810  MacroExpandingLexersStack.pop_back();
811}
812
813/// ComputeDATE_TIME - Compute the current time, enter it into the specified
814/// scratch buffer, then return DATELoc/TIMELoc locations with the position of
815/// the identifier tokens inserted.
816static void ComputeDATE_TIME(SourceLocation &DATELoc, SourceLocation &TIMELoc,
817                             Preprocessor &PP) {
818  time_t TT = time(nullptr);
819  struct tm *TM = localtime(&TT);
820
821  static const char * const Months[] = {
822    "Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"
823  };
824
825  {
826    SmallString<32> TmpBuffer;
827    llvm::raw_svector_ostream TmpStream(TmpBuffer);
828    TmpStream << llvm::format("\"%s %2d %4d\"", Months[TM->tm_mon],
829                              TM->tm_mday, TM->tm_year + 1900);
830    Token TmpTok;
831    TmpTok.startToken();
832    PP.CreateString(TmpStream.str(), TmpTok);
833    DATELoc = TmpTok.getLocation();
834  }
835
836  {
837    SmallString<32> TmpBuffer;
838    llvm::raw_svector_ostream TmpStream(TmpBuffer);
839    TmpStream << llvm::format("\"%02d:%02d:%02d\"",
840                              TM->tm_hour, TM->tm_min, TM->tm_sec);
841    Token TmpTok;
842    TmpTok.startToken();
843    PP.CreateString(TmpStream.str(), TmpTok);
844    TIMELoc = TmpTok.getLocation();
845  }
846}
847
848
849/// HasFeature - Return true if we recognize and implement the feature
850/// specified by the identifier as a standard language feature.
851static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
852  const LangOptions &LangOpts = PP.getLangOpts();
853  StringRef Feature = II->getName();
854
855  // Normalize the feature name, __foo__ becomes foo.
856  if (Feature.startswith("__") && Feature.endswith("__") && Feature.size() >= 4)
857    Feature = Feature.substr(2, Feature.size() - 4);
858
859  return llvm::StringSwitch<bool>(Feature)
860           .Case("address_sanitizer", LangOpts.Sanitize.Address)
861           .Case("attribute_analyzer_noreturn", true)
862           .Case("attribute_availability", true)
863           .Case("attribute_availability_with_message", true)
864           .Case("attribute_cf_returns_not_retained", true)
865           .Case("attribute_cf_returns_retained", true)
866           .Case("attribute_deprecated_with_message", true)
867           .Case("attribute_ext_vector_type", true)
868           .Case("attribute_ns_returns_not_retained", true)
869           .Case("attribute_ns_returns_retained", true)
870           .Case("attribute_ns_consumes_self", true)
871           .Case("attribute_ns_consumed", true)
872           .Case("attribute_cf_consumed", true)
873           .Case("attribute_objc_ivar_unused", true)
874           .Case("attribute_objc_method_family", true)
875           .Case("attribute_overloadable", true)
876           .Case("attribute_unavailable_with_message", true)
877           .Case("attribute_unused_on_fields", true)
878           .Case("blocks", LangOpts.Blocks)
879           .Case("c_thread_safety_attributes", true)
880           .Case("cxx_exceptions", LangOpts.CXXExceptions)
881           .Case("cxx_rtti", LangOpts.RTTI)
882           .Case("enumerator_attributes", true)
883           .Case("memory_sanitizer", LangOpts.Sanitize.Memory)
884           .Case("thread_sanitizer", LangOpts.Sanitize.Thread)
885           .Case("dataflow_sanitizer", LangOpts.Sanitize.DataFlow)
886           // Objective-C features
887           .Case("objc_arr", LangOpts.ObjCAutoRefCount) // FIXME: REMOVE?
888           .Case("objc_arc", LangOpts.ObjCAutoRefCount)
889           .Case("objc_arc_weak", LangOpts.ObjCARCWeak)
890           .Case("objc_default_synthesize_properties", LangOpts.ObjC2)
891           .Case("objc_fixed_enum", LangOpts.ObjC2)
892           .Case("objc_instancetype", LangOpts.ObjC2)
893           .Case("objc_modules", LangOpts.ObjC2 && LangOpts.Modules)
894           .Case("objc_nonfragile_abi", LangOpts.ObjCRuntime.isNonFragile())
895           .Case("objc_property_explicit_atomic", true) // Does clang support explicit "atomic" keyword?
896           .Case("objc_protocol_qualifier_mangling", true)
897           .Case("objc_weak_class", LangOpts.ObjCRuntime.hasWeakClassImport())
898           .Case("ownership_holds", true)
899           .Case("ownership_returns", true)
900           .Case("ownership_takes", true)
901           .Case("objc_bool", true)
902           .Case("objc_subscripting", LangOpts.ObjCRuntime.isNonFragile())
903           .Case("objc_array_literals", LangOpts.ObjC2)
904           .Case("objc_dictionary_literals", LangOpts.ObjC2)
905           .Case("objc_boxed_expressions", LangOpts.ObjC2)
906           .Case("arc_cf_code_audited", true)
907           // C11 features
908           .Case("c_alignas", LangOpts.C11)
909           .Case("c_atomic", LangOpts.C11)
910           .Case("c_generic_selections", LangOpts.C11)
911           .Case("c_static_assert", LangOpts.C11)
912           .Case("c_thread_local",
913                 LangOpts.C11 && PP.getTargetInfo().isTLSSupported())
914           // C++11 features
915           .Case("cxx_access_control_sfinae", LangOpts.CPlusPlus11)
916           .Case("cxx_alias_templates", LangOpts.CPlusPlus11)
917           .Case("cxx_alignas", LangOpts.CPlusPlus11)
918           .Case("cxx_atomic", LangOpts.CPlusPlus11)
919           .Case("cxx_attributes", LangOpts.CPlusPlus11)
920           .Case("cxx_auto_type", LangOpts.CPlusPlus11)
921           .Case("cxx_constexpr", LangOpts.CPlusPlus11)
922           .Case("cxx_decltype", LangOpts.CPlusPlus11)
923           .Case("cxx_decltype_incomplete_return_types", LangOpts.CPlusPlus11)
924           .Case("cxx_default_function_template_args", LangOpts.CPlusPlus11)
925           .Case("cxx_defaulted_functions", LangOpts.CPlusPlus11)
926           .Case("cxx_delegating_constructors", LangOpts.CPlusPlus11)
927           .Case("cxx_deleted_functions", LangOpts.CPlusPlus11)
928           .Case("cxx_explicit_conversions", LangOpts.CPlusPlus11)
929           .Case("cxx_generalized_initializers", LangOpts.CPlusPlus11)
930           .Case("cxx_implicit_moves", LangOpts.CPlusPlus11)
931           .Case("cxx_inheriting_constructors", LangOpts.CPlusPlus11)
932           .Case("cxx_inline_namespaces", LangOpts.CPlusPlus11)
933           .Case("cxx_lambdas", LangOpts.CPlusPlus11)
934           .Case("cxx_local_type_template_args", LangOpts.CPlusPlus11)
935           .Case("cxx_nonstatic_member_init", LangOpts.CPlusPlus11)
936           .Case("cxx_noexcept", LangOpts.CPlusPlus11)
937           .Case("cxx_nullptr", LangOpts.CPlusPlus11)
938           .Case("cxx_override_control", LangOpts.CPlusPlus11)
939           .Case("cxx_range_for", LangOpts.CPlusPlus11)
940           .Case("cxx_raw_string_literals", LangOpts.CPlusPlus11)
941           .Case("cxx_reference_qualified_functions", LangOpts.CPlusPlus11)
942           .Case("cxx_rvalue_references", LangOpts.CPlusPlus11)
943           .Case("cxx_strong_enums", LangOpts.CPlusPlus11)
944           .Case("cxx_static_assert", LangOpts.CPlusPlus11)
945           .Case("cxx_thread_local",
946                 LangOpts.CPlusPlus11 && PP.getTargetInfo().isTLSSupported())
947           .Case("cxx_trailing_return", LangOpts.CPlusPlus11)
948           .Case("cxx_unicode_literals", LangOpts.CPlusPlus11)
949           .Case("cxx_unrestricted_unions", LangOpts.CPlusPlus11)
950           .Case("cxx_user_literals", LangOpts.CPlusPlus11)
951           .Case("cxx_variadic_templates", LangOpts.CPlusPlus11)
952           // C++1y features
953           .Case("cxx_aggregate_nsdmi", LangOpts.CPlusPlus1y)
954           .Case("cxx_binary_literals", LangOpts.CPlusPlus1y)
955           .Case("cxx_contextual_conversions", LangOpts.CPlusPlus1y)
956           .Case("cxx_decltype_auto", LangOpts.CPlusPlus1y)
957           .Case("cxx_generic_lambdas", LangOpts.CPlusPlus1y)
958           .Case("cxx_init_captures", LangOpts.CPlusPlus1y)
959           .Case("cxx_relaxed_constexpr", LangOpts.CPlusPlus1y)
960           .Case("cxx_return_type_deduction", LangOpts.CPlusPlus1y)
961           .Case("cxx_variable_templates", LangOpts.CPlusPlus1y)
962           // C++ TSes
963           //.Case("cxx_runtime_arrays", LangOpts.CPlusPlusTSArrays)
964           //.Case("cxx_concepts", LangOpts.CPlusPlusTSConcepts)
965           // FIXME: Should this be __has_feature or __has_extension?
966           //.Case("raw_invocation_type", LangOpts.CPlusPlus)
967           // Type traits
968           .Case("has_nothrow_assign", LangOpts.CPlusPlus)
969           .Case("has_nothrow_copy", LangOpts.CPlusPlus)
970           .Case("has_nothrow_constructor", LangOpts.CPlusPlus)
971           .Case("has_trivial_assign", LangOpts.CPlusPlus)
972           .Case("has_trivial_copy", LangOpts.CPlusPlus)
973           .Case("has_trivial_constructor", LangOpts.CPlusPlus)
974           .Case("has_trivial_destructor", LangOpts.CPlusPlus)
975           .Case("has_virtual_destructor", LangOpts.CPlusPlus)
976           .Case("is_abstract", LangOpts.CPlusPlus)
977           .Case("is_base_of", LangOpts.CPlusPlus)
978           .Case("is_class", LangOpts.CPlusPlus)
979           .Case("is_constructible", LangOpts.CPlusPlus)
980           .Case("is_convertible_to", LangOpts.CPlusPlus)
981           .Case("is_empty", LangOpts.CPlusPlus)
982           .Case("is_enum", LangOpts.CPlusPlus)
983           .Case("is_final", LangOpts.CPlusPlus)
984           .Case("is_literal", LangOpts.CPlusPlus)
985           .Case("is_standard_layout", LangOpts.CPlusPlus)
986           .Case("is_pod", LangOpts.CPlusPlus)
987           .Case("is_polymorphic", LangOpts.CPlusPlus)
988           .Case("is_sealed", LangOpts.MicrosoftExt)
989           .Case("is_trivial", LangOpts.CPlusPlus)
990           .Case("is_trivially_assignable", LangOpts.CPlusPlus)
991           .Case("is_trivially_constructible", LangOpts.CPlusPlus)
992           .Case("is_trivially_copyable", LangOpts.CPlusPlus)
993           .Case("is_union", LangOpts.CPlusPlus)
994           .Case("modules", LangOpts.Modules)
995           .Case("tls", PP.getTargetInfo().isTLSSupported())
996           .Case("underlying_type", LangOpts.CPlusPlus)
997           .Default(false);
998}
999
1000/// HasExtension - Return true if we recognize and implement the feature
1001/// specified by the identifier, either as an extension or a standard language
1002/// feature.
1003static bool HasExtension(const Preprocessor &PP, const IdentifierInfo *II) {
1004  if (HasFeature(PP, II))
1005    return true;
1006
1007  // If the use of an extension results in an error diagnostic, extensions are
1008  // effectively unavailable, so just return false here.
1009  if (PP.getDiagnostics().getExtensionHandlingBehavior() >=
1010      diag::Severity::Error)
1011    return false;
1012
1013  const LangOptions &LangOpts = PP.getLangOpts();
1014  StringRef Extension = II->getName();
1015
1016  // Normalize the extension name, __foo__ becomes foo.
1017  if (Extension.startswith("__") && Extension.endswith("__") &&
1018      Extension.size() >= 4)
1019    Extension = Extension.substr(2, Extension.size() - 4);
1020
1021  // Because we inherit the feature list from HasFeature, this string switch
1022  // must be less restrictive than HasFeature's.
1023  return llvm::StringSwitch<bool>(Extension)
1024           // C11 features supported by other languages as extensions.
1025           .Case("c_alignas", true)
1026           .Case("c_atomic", true)
1027           .Case("c_generic_selections", true)
1028           .Case("c_static_assert", true)
1029           .Case("c_thread_local", PP.getTargetInfo().isTLSSupported())
1030           // C++11 features supported by other languages as extensions.
1031           .Case("cxx_atomic", LangOpts.CPlusPlus)
1032           .Case("cxx_deleted_functions", LangOpts.CPlusPlus)
1033           .Case("cxx_explicit_conversions", LangOpts.CPlusPlus)
1034           .Case("cxx_inline_namespaces", LangOpts.CPlusPlus)
1035           .Case("cxx_local_type_template_args", LangOpts.CPlusPlus)
1036           .Case("cxx_nonstatic_member_init", LangOpts.CPlusPlus)
1037           .Case("cxx_override_control", LangOpts.CPlusPlus)
1038           .Case("cxx_range_for", LangOpts.CPlusPlus)
1039           .Case("cxx_reference_qualified_functions", LangOpts.CPlusPlus)
1040           .Case("cxx_rvalue_references", LangOpts.CPlusPlus)
1041           // C++1y features supported by other languages as extensions.
1042           .Case("cxx_binary_literals", true)
1043           .Case("cxx_init_captures", LangOpts.CPlusPlus11)
1044           .Case("cxx_variable_templates", LangOpts.CPlusPlus)
1045           .Default(false);
1046}
1047
1048/// EvaluateHasIncludeCommon - Process a '__has_include("path")'
1049/// or '__has_include_next("path")' expression.
1050/// Returns true if successful.
1051static bool EvaluateHasIncludeCommon(Token &Tok,
1052                                     IdentifierInfo *II, Preprocessor &PP,
1053                                     const DirectoryLookup *LookupFrom) {
1054  // Save the location of the current token.  If a '(' is later found, use
1055  // that location.  If not, use the end of this location instead.
1056  SourceLocation LParenLoc = Tok.getLocation();
1057
1058  // These expressions are only allowed within a preprocessor directive.
1059  if (!PP.isParsingIfOrElifDirective()) {
1060    PP.Diag(LParenLoc, diag::err_pp_directive_required) << II->getName();
1061    return false;
1062  }
1063
1064  // Get '('.
1065  PP.LexNonComment(Tok);
1066
1067  // Ensure we have a '('.
1068  if (Tok.isNot(tok::l_paren)) {
1069    // No '(', use end of last token.
1070    LParenLoc = PP.getLocForEndOfToken(LParenLoc);
1071    PP.Diag(LParenLoc, diag::err_pp_expected_after) << II << tok::l_paren;
1072    // If the next token looks like a filename or the start of one,
1073    // assume it is and process it as such.
1074    if (!Tok.is(tok::angle_string_literal) && !Tok.is(tok::string_literal) &&
1075        !Tok.is(tok::less))
1076      return false;
1077  } else {
1078    // Save '(' location for possible missing ')' message.
1079    LParenLoc = Tok.getLocation();
1080
1081    if (PP.getCurrentLexer()) {
1082      // Get the file name.
1083      PP.getCurrentLexer()->LexIncludeFilename(Tok);
1084    } else {
1085      // We're in a macro, so we can't use LexIncludeFilename; just
1086      // grab the next token.
1087      PP.Lex(Tok);
1088    }
1089  }
1090
1091  // Reserve a buffer to get the spelling.
1092  SmallString<128> FilenameBuffer;
1093  StringRef Filename;
1094  SourceLocation EndLoc;
1095
1096  switch (Tok.getKind()) {
1097  case tok::eod:
1098    // If the token kind is EOD, the error has already been diagnosed.
1099    return false;
1100
1101  case tok::angle_string_literal:
1102  case tok::string_literal: {
1103    bool Invalid = false;
1104    Filename = PP.getSpelling(Tok, FilenameBuffer, &Invalid);
1105    if (Invalid)
1106      return false;
1107    break;
1108  }
1109
1110  case tok::less:
1111    // This could be a <foo/bar.h> file coming from a macro expansion.  In this
1112    // case, glue the tokens together into FilenameBuffer and interpret those.
1113    FilenameBuffer.push_back('<');
1114    if (PP.ConcatenateIncludeName(FilenameBuffer, EndLoc)) {
1115      // Let the caller know a <eod> was found by changing the Token kind.
1116      Tok.setKind(tok::eod);
1117      return false;   // Found <eod> but no ">"?  Diagnostic already emitted.
1118    }
1119    Filename = FilenameBuffer.str();
1120    break;
1121  default:
1122    PP.Diag(Tok.getLocation(), diag::err_pp_expects_filename);
1123    return false;
1124  }
1125
1126  SourceLocation FilenameLoc = Tok.getLocation();
1127
1128  // Get ')'.
1129  PP.LexNonComment(Tok);
1130
1131  // Ensure we have a trailing ).
1132  if (Tok.isNot(tok::r_paren)) {
1133    PP.Diag(PP.getLocForEndOfToken(FilenameLoc), diag::err_pp_expected_after)
1134        << II << tok::r_paren;
1135    PP.Diag(LParenLoc, diag::note_matching) << tok::l_paren;
1136    return false;
1137  }
1138
1139  bool isAngled = PP.GetIncludeFilenameSpelling(Tok.getLocation(), Filename);
1140  // If GetIncludeFilenameSpelling set the start ptr to null, there was an
1141  // error.
1142  if (Filename.empty())
1143    return false;
1144
1145  // Search include directories.
1146  const DirectoryLookup *CurDir;
1147  const FileEntry *File =
1148      PP.LookupFile(FilenameLoc, Filename, isAngled, LookupFrom, CurDir,
1149                    nullptr, nullptr, nullptr);
1150
1151  // Get the result value.  A result of true means the file exists.
1152  return File != nullptr;
1153}
1154
1155/// EvaluateHasInclude - Process a '__has_include("path")' expression.
1156/// Returns true if successful.
1157static bool EvaluateHasInclude(Token &Tok, IdentifierInfo *II,
1158                               Preprocessor &PP) {
1159  return EvaluateHasIncludeCommon(Tok, II, PP, nullptr);
1160}
1161
1162/// EvaluateHasIncludeNext - Process '__has_include_next("path")' expression.
1163/// Returns true if successful.
1164static bool EvaluateHasIncludeNext(Token &Tok,
1165                                   IdentifierInfo *II, Preprocessor &PP) {
1166  // __has_include_next is like __has_include, except that we start
1167  // searching after the current found directory.  If we can't do this,
1168  // issue a diagnostic.
1169  const DirectoryLookup *Lookup = PP.GetCurDirLookup();
1170  if (PP.isInPrimaryFile()) {
1171    Lookup = nullptr;
1172    PP.Diag(Tok, diag::pp_include_next_in_primary);
1173  } else if (!Lookup) {
1174    PP.Diag(Tok, diag::pp_include_next_absolute_path);
1175  } else {
1176    // Start looking up in the next directory.
1177    ++Lookup;
1178  }
1179
1180  return EvaluateHasIncludeCommon(Tok, II, PP, Lookup);
1181}
1182
1183/// \brief Process __building_module(identifier) expression.
1184/// \returns true if we are building the named module, false otherwise.
1185static bool EvaluateBuildingModule(Token &Tok,
1186                                   IdentifierInfo *II, Preprocessor &PP) {
1187  // Get '('.
1188  PP.LexNonComment(Tok);
1189
1190  // Ensure we have a '('.
1191  if (Tok.isNot(tok::l_paren)) {
1192    PP.Diag(Tok.getLocation(), diag::err_pp_expected_after) << II
1193                                                            << tok::l_paren;
1194    return false;
1195  }
1196
1197  // Save '(' location for possible missing ')' message.
1198  SourceLocation LParenLoc = Tok.getLocation();
1199
1200  // Get the module name.
1201  PP.LexNonComment(Tok);
1202
1203  // Ensure that we have an identifier.
1204  if (Tok.isNot(tok::identifier)) {
1205    PP.Diag(Tok.getLocation(), diag::err_expected_id_building_module);
1206    return false;
1207  }
1208
1209  bool Result
1210    = Tok.getIdentifierInfo()->getName() == PP.getLangOpts().CurrentModule;
1211
1212  // Get ')'.
1213  PP.LexNonComment(Tok);
1214
1215  // Ensure we have a trailing ).
1216  if (Tok.isNot(tok::r_paren)) {
1217    PP.Diag(Tok.getLocation(), diag::err_pp_expected_after) << II
1218                                                            << tok::r_paren;
1219    PP.Diag(LParenLoc, diag::note_matching) << tok::l_paren;
1220    return false;
1221  }
1222
1223  return Result;
1224}
1225
1226/// ExpandBuiltinMacro - If an identifier token is read that is to be expanded
1227/// as a builtin macro, handle it and return the next token as 'Tok'.
1228void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
1229  // Figure out which token this is.
1230  IdentifierInfo *II = Tok.getIdentifierInfo();
1231  assert(II && "Can't be a macro without id info!");
1232
1233  // If this is an _Pragma or Microsoft __pragma directive, expand it,
1234  // invoke the pragma handler, then lex the token after it.
1235  if (II == Ident_Pragma)
1236    return Handle_Pragma(Tok);
1237  else if (II == Ident__pragma) // in non-MS mode this is null
1238    return HandleMicrosoft__pragma(Tok);
1239
1240  ++NumBuiltinMacroExpanded;
1241
1242  SmallString<128> TmpBuffer;
1243  llvm::raw_svector_ostream OS(TmpBuffer);
1244
1245  // Set up the return result.
1246  Tok.setIdentifierInfo(nullptr);
1247  Tok.clearFlag(Token::NeedsCleaning);
1248
1249  if (II == Ident__LINE__) {
1250    // C99 6.10.8: "__LINE__: The presumed line number (within the current
1251    // source file) of the current source line (an integer constant)".  This can
1252    // be affected by #line.
1253    SourceLocation Loc = Tok.getLocation();
1254
1255    // Advance to the location of the first _, this might not be the first byte
1256    // of the token if it starts with an escaped newline.
1257    Loc = AdvanceToTokenCharacter(Loc, 0);
1258
1259    // One wrinkle here is that GCC expands __LINE__ to location of the *end* of
1260    // a macro expansion.  This doesn't matter for object-like macros, but
1261    // can matter for a function-like macro that expands to contain __LINE__.
1262    // Skip down through expansion points until we find a file loc for the
1263    // end of the expansion history.
1264    Loc = SourceMgr.getExpansionRange(Loc).second;
1265    PresumedLoc PLoc = SourceMgr.getPresumedLoc(Loc);
1266
1267    // __LINE__ expands to a simple numeric value.
1268    OS << (PLoc.isValid()? PLoc.getLine() : 1);
1269    Tok.setKind(tok::numeric_constant);
1270  } else if (II == Ident__FILE__ || II == Ident__BASE_FILE__) {
1271    // C99 6.10.8: "__FILE__: The presumed name of the current source file (a
1272    // character string literal)". This can be affected by #line.
1273    PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation());
1274
1275    // __BASE_FILE__ is a GNU extension that returns the top of the presumed
1276    // #include stack instead of the current file.
1277    if (II == Ident__BASE_FILE__ && PLoc.isValid()) {
1278      SourceLocation NextLoc = PLoc.getIncludeLoc();
1279      while (NextLoc.isValid()) {
1280        PLoc = SourceMgr.getPresumedLoc(NextLoc);
1281        if (PLoc.isInvalid())
1282          break;
1283
1284        NextLoc = PLoc.getIncludeLoc();
1285      }
1286    }
1287
1288    // Escape this filename.  Turn '\' -> '\\' '"' -> '\"'
1289    SmallString<128> FN;
1290    if (PLoc.isValid()) {
1291      FN += PLoc.getFilename();
1292      Lexer::Stringify(FN);
1293      OS << '"' << FN.str() << '"';
1294    }
1295    Tok.setKind(tok::string_literal);
1296  } else if (II == Ident__DATE__) {
1297    Diag(Tok.getLocation(), diag::warn_pp_date_time);
1298    if (!DATELoc.isValid())
1299      ComputeDATE_TIME(DATELoc, TIMELoc, *this);
1300    Tok.setKind(tok::string_literal);
1301    Tok.setLength(strlen("\"Mmm dd yyyy\""));
1302    Tok.setLocation(SourceMgr.createExpansionLoc(DATELoc, Tok.getLocation(),
1303                                                 Tok.getLocation(),
1304                                                 Tok.getLength()));
1305    return;
1306  } else if (II == Ident__TIME__) {
1307    Diag(Tok.getLocation(), diag::warn_pp_date_time);
1308    if (!TIMELoc.isValid())
1309      ComputeDATE_TIME(DATELoc, TIMELoc, *this);
1310    Tok.setKind(tok::string_literal);
1311    Tok.setLength(strlen("\"hh:mm:ss\""));
1312    Tok.setLocation(SourceMgr.createExpansionLoc(TIMELoc, Tok.getLocation(),
1313                                                 Tok.getLocation(),
1314                                                 Tok.getLength()));
1315    return;
1316  } else if (II == Ident__INCLUDE_LEVEL__) {
1317    // Compute the presumed include depth of this token.  This can be affected
1318    // by GNU line markers.
1319    unsigned Depth = 0;
1320
1321    PresumedLoc PLoc = SourceMgr.getPresumedLoc(Tok.getLocation());
1322    if (PLoc.isValid()) {
1323      PLoc = SourceMgr.getPresumedLoc(PLoc.getIncludeLoc());
1324      for (; PLoc.isValid(); ++Depth)
1325        PLoc = SourceMgr.getPresumedLoc(PLoc.getIncludeLoc());
1326    }
1327
1328    // __INCLUDE_LEVEL__ expands to a simple numeric value.
1329    OS << Depth;
1330    Tok.setKind(tok::numeric_constant);
1331  } else if (II == Ident__TIMESTAMP__) {
1332    Diag(Tok.getLocation(), diag::warn_pp_date_time);
1333    // MSVC, ICC, GCC, VisualAge C++ extension.  The generated string should be
1334    // of the form "Ddd Mmm dd hh::mm::ss yyyy", which is returned by asctime.
1335
1336    // Get the file that we are lexing out of.  If we're currently lexing from
1337    // a macro, dig into the include stack.
1338    const FileEntry *CurFile = nullptr;
1339    PreprocessorLexer *TheLexer = getCurrentFileLexer();
1340
1341    if (TheLexer)
1342      CurFile = SourceMgr.getFileEntryForID(TheLexer->getFileID());
1343
1344    const char *Result;
1345    if (CurFile) {
1346      time_t TT = CurFile->getModificationTime();
1347      struct tm *TM = localtime(&TT);
1348      Result = asctime(TM);
1349    } else {
1350      Result = "??? ??? ?? ??:??:?? ????\n";
1351    }
1352    // Surround the string with " and strip the trailing newline.
1353    OS << '"' << StringRef(Result).drop_back() << '"';
1354    Tok.setKind(tok::string_literal);
1355  } else if (II == Ident__COUNTER__) {
1356    // __COUNTER__ expands to a simple numeric value.
1357    OS << CounterValue++;
1358    Tok.setKind(tok::numeric_constant);
1359  } else if (II == Ident__has_feature   ||
1360             II == Ident__has_extension ||
1361             II == Ident__has_builtin   ||
1362             II == Ident__is_identifier ||
1363             II == Ident__has_attribute) {
1364    // The argument to these builtins should be a parenthesized identifier.
1365    SourceLocation StartLoc = Tok.getLocation();
1366
1367    bool IsValid = false;
1368    IdentifierInfo *FeatureII = nullptr;
1369
1370    // Read the '('.
1371    LexUnexpandedToken(Tok);
1372    if (Tok.is(tok::l_paren)) {
1373      // Read the identifier
1374      LexUnexpandedToken(Tok);
1375      if ((FeatureII = Tok.getIdentifierInfo())) {
1376        // Read the ')'.
1377        LexUnexpandedToken(Tok);
1378        if (Tok.is(tok::r_paren))
1379          IsValid = true;
1380      }
1381    }
1382
1383    bool Value = false;
1384    if (!IsValid)
1385      Diag(StartLoc, diag::err_feature_check_malformed);
1386    else if (II == Ident__is_identifier)
1387      Value = FeatureII->getTokenID() == tok::identifier;
1388    else if (II == Ident__has_builtin) {
1389      // Check for a builtin is trivial.
1390      Value = FeatureII->getBuiltinID() != 0;
1391    } else if (II == Ident__has_attribute)
1392      Value = hasAttribute(AttrSyntax::Generic, nullptr, FeatureII,
1393                           getTargetInfo().getTriple(), getLangOpts());
1394    else if (II == Ident__has_extension)
1395      Value = HasExtension(*this, FeatureII);
1396    else {
1397      assert(II == Ident__has_feature && "Must be feature check");
1398      Value = HasFeature(*this, FeatureII);
1399    }
1400
1401    OS << (int)Value;
1402    if (IsValid)
1403      Tok.setKind(tok::numeric_constant);
1404  } else if (II == Ident__has_include ||
1405             II == Ident__has_include_next) {
1406    // The argument to these two builtins should be a parenthesized
1407    // file name string literal using angle brackets (<>) or
1408    // double-quotes ("").
1409    bool Value;
1410    if (II == Ident__has_include)
1411      Value = EvaluateHasInclude(Tok, II, *this);
1412    else
1413      Value = EvaluateHasIncludeNext(Tok, II, *this);
1414    OS << (int)Value;
1415    if (Tok.is(tok::r_paren))
1416      Tok.setKind(tok::numeric_constant);
1417  } else if (II == Ident__has_warning) {
1418    // The argument should be a parenthesized string literal.
1419    // The argument to these builtins should be a parenthesized identifier.
1420    SourceLocation StartLoc = Tok.getLocation();
1421    bool IsValid = false;
1422    bool Value = false;
1423    // Read the '('.
1424    LexUnexpandedToken(Tok);
1425    do {
1426      if (Tok.isNot(tok::l_paren)) {
1427        Diag(StartLoc, diag::err_warning_check_malformed);
1428        break;
1429      }
1430
1431      LexUnexpandedToken(Tok);
1432      std::string WarningName;
1433      SourceLocation StrStartLoc = Tok.getLocation();
1434      if (!FinishLexStringLiteral(Tok, WarningName, "'__has_warning'",
1435                                  /*MacroExpansion=*/false)) {
1436        // Eat tokens until ')'.
1437        while (Tok.isNot(tok::r_paren) && Tok.isNot(tok::eod) &&
1438               Tok.isNot(tok::eof))
1439          LexUnexpandedToken(Tok);
1440        break;
1441      }
1442
1443      // Is the end a ')'?
1444      if (!(IsValid = Tok.is(tok::r_paren))) {
1445        Diag(StartLoc, diag::err_warning_check_malformed);
1446        break;
1447      }
1448
1449      if (WarningName.size() < 3 || WarningName[0] != '-' ||
1450          WarningName[1] != 'W') {
1451        Diag(StrStartLoc, diag::warn_has_warning_invalid_option);
1452        break;
1453      }
1454
1455      // Finally, check if the warning flags maps to a diagnostic group.
1456      // We construct a SmallVector here to talk to getDiagnosticIDs().
1457      // Although we don't use the result, this isn't a hot path, and not
1458      // worth special casing.
1459      SmallVector<diag::kind, 10> Diags;
1460      Value = !getDiagnostics().getDiagnosticIDs()->
1461        getDiagnosticsInGroup(WarningName.substr(2), Diags);
1462    } while (false);
1463
1464    OS << (int)Value;
1465    if (IsValid)
1466      Tok.setKind(tok::numeric_constant);
1467  } else if (II == Ident__building_module) {
1468    // The argument to this builtin should be an identifier. The
1469    // builtin evaluates to 1 when that identifier names the module we are
1470    // currently building.
1471    OS << (int)EvaluateBuildingModule(Tok, II, *this);
1472    Tok.setKind(tok::numeric_constant);
1473  } else if (II == Ident__MODULE__) {
1474    // The current module as an identifier.
1475    OS << getLangOpts().CurrentModule;
1476    IdentifierInfo *ModuleII = getIdentifierInfo(getLangOpts().CurrentModule);
1477    Tok.setIdentifierInfo(ModuleII);
1478    Tok.setKind(ModuleII->getTokenID());
1479  } else if (II == Ident__identifier) {
1480    SourceLocation Loc = Tok.getLocation();
1481
1482    // We're expecting '__identifier' '(' identifier ')'. Try to recover
1483    // if the parens are missing.
1484    LexNonComment(Tok);
1485    if (Tok.isNot(tok::l_paren)) {
1486      // No '(', use end of last token.
1487      Diag(getLocForEndOfToken(Loc), diag::err_pp_expected_after)
1488        << II << tok::l_paren;
1489      // If the next token isn't valid as our argument, we can't recover.
1490      if (!Tok.isAnnotation() && Tok.getIdentifierInfo())
1491        Tok.setKind(tok::identifier);
1492      return;
1493    }
1494
1495    SourceLocation LParenLoc = Tok.getLocation();
1496    LexNonComment(Tok);
1497
1498    if (!Tok.isAnnotation() && Tok.getIdentifierInfo())
1499      Tok.setKind(tok::identifier);
1500    else {
1501      Diag(Tok.getLocation(), diag::err_pp_identifier_arg_not_identifier)
1502        << Tok.getKind();
1503      // Don't walk past anything that's not a real token.
1504      if (Tok.is(tok::eof) || Tok.is(tok::eod) || Tok.isAnnotation())
1505        return;
1506    }
1507
1508    // Discard the ')', preserving 'Tok' as our result.
1509    Token RParen;
1510    LexNonComment(RParen);
1511    if (RParen.isNot(tok::r_paren)) {
1512      Diag(getLocForEndOfToken(Tok.getLocation()), diag::err_pp_expected_after)
1513        << Tok.getKind() << tok::r_paren;
1514      Diag(LParenLoc, diag::note_matching) << tok::l_paren;
1515    }
1516    return;
1517  } else {
1518    llvm_unreachable("Unknown identifier!");
1519  }
1520  CreateString(OS.str(), Tok, Tok.getLocation(), Tok.getLocation());
1521}
1522
1523void Preprocessor::markMacroAsUsed(MacroInfo *MI) {
1524  // If the 'used' status changed, and the macro requires 'unused' warning,
1525  // remove its SourceLocation from the warn-for-unused-macro locations.
1526  if (MI->isWarnIfUnused() && !MI->isUsed())
1527    WarnUnusedMacroLocs.erase(MI->getDefinitionLoc());
1528  MI->setIsUsed(true);
1529}
1530