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      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>
     34 using namespace clang;
     35 
     36 MacroDirective *
     37 Preprocessor::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 
     45 void 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 
     59 void 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.
     74 static 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.
     88 void 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.
    137 static 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.
    175 bool 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'.
    217 bool 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 
    378 enum Bracket {
    379   Brace,
    380   Paren
    381 };
    382 
    383 /// CheckMatchedBrackets - Returns true if the braces and parentheses in the
    384 /// token vector are properly nested.
    385 static 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.
    416 static 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.
    512 MacroArgs *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.
    778 Token *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 
    804 void 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.
    816 static 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.
    851 static 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.
   1003 static 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.
   1051 static 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.
   1157 static 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.
   1164 static 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.
   1185 static 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'.
   1228 void 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 
   1523 void 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