//===- Preprocessor.cpp - C Language Family Preprocessor Implementation ---===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

//  This file implements the Preprocessor interface.

//

//===----------------------------------------------------------------------===//

//

// Options to support:

//   -H       - Print the name of each header file used.

//   -d[DNI] - Dump various things.

//   -fworking-directory - #line's with preprocessor's working dir.

//   -fpreprocessed

//   -dependency-file,-M,-MM,-MF,-MG,-MP,-MT,-MQ,-MD,-MMD

//   -W*

//   -w

//

// Messages to emit:

//   "Multiple include guards may be useful for:\n"

//

//===----------------------------------------------------------------------===//

#include "clang/Lex/Preprocessor.h"

#include "clang/Basic/Builtins.h"

#include "clang/Basic/FileManager.h"

#include "clang/Basic/FileSystemStatCache.h"

#include "clang/Basic/IdentifierTable.h"

#include "clang/Basic/LLVM.h"

#include "clang/Basic/LangOptions.h"

#include "clang/Basic/Module.h"

#include "clang/Basic/SourceLocation.h"

#include "clang/Basic/SourceManager.h"

#include "clang/Basic/TargetInfo.h"

#include "clang/Lex/CodeCompletionHandler.h"

#include "clang/Lex/ExternalPreprocessorSource.h"

#include "clang/Lex/HeaderSearch.h"

#include "clang/Lex/LexDiagnostic.h"

#include "clang/Lex/Lexer.h"

#include "clang/Lex/LiteralSupport.h"

#include "clang/Lex/MacroArgs.h"

#include "clang/Lex/MacroInfo.h"

#include "clang/Lex/ModuleLoader.h"

#include "clang/Lex/Pragma.h"

#include "clang/Lex/PreprocessingRecord.h"

#include "clang/Lex/PreprocessorLexer.h"

#include "clang/Lex/PreprocessorOptions.h"

#include "clang/Lex/ScratchBuffer.h"

#include "clang/Lex/Token.h"

#include "clang/Lex/TokenLexer.h"

#include "llvm/ADT/APInt.h"

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/DenseMap.h"

#include "llvm/ADT/STLExtras.h"

#include "llvm/ADT/SmallString.h"

#include "llvm/ADT/SmallVector.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/ADT/StringSwitch.h"

#include "llvm/Support/Capacity.h"

#include "llvm/Support/ErrorHandling.h"

#include "llvm/Support/MemoryBuffer.h"

#include "llvm/Support/raw_ostream.h"

#include <algorithm>

#include <cassert>

#include <memory>

#include <string>

#include <utility>

#include <vector>

using namespace clang;

LLVM_INSTANTIATE_REGISTRY(PragmaHandlerRegistry)

ExternalPreprocessorSource::~ExternalPreprocessorSource() = default;

Preprocessor::Preprocessor(std::shared_ptr<PreprocessorOptions> PPOpts,

                           DiagnosticsEngine &diags, LangOptions &opts,

                           SourceManager &SM, HeaderSearch &Headers,

                           ModuleLoader &TheModuleLoader,

                           IdentifierInfoLookup *IILookup, bool OwnsHeaders,

                           TranslationUnitKind TUKind)

    : PPOpts(std::move(PPOpts)), Diags(&diags), LangOpts(opts),

      FileMgr(Headers.getFileMgr()), SourceMgr(SM),

      ScratchBuf(new ScratchBuffer(SourceMgr)), HeaderInfo(Headers),

      TheModuleLoader(TheModuleLoader), ExternalSource(nullptr),

      // As the language options may have not been loaded yet (when

      // deserializing an ASTUnit), adding keywords to the identifier table is

      // deferred to Preprocessor::Initialize().

      Identifiers(IILookup), PragmaHandlers(new PragmaNamespace(StringRef())),

      TUKind(TUKind), SkipMainFilePreamble(0, true),

      CurSubmoduleState(&NullSubmoduleState) {

  OwnsHeaderSearch = OwnsHeaders;

  // Default to discarding comments.

  KeepComments = false;

  KeepMacroComments = false;

  SuppressIncludeNotFoundError = false;

  // Macro expansion is enabled.

  DisableMacroExpansion = false;

  MacroExpansionInDirectivesOverride = false;

  InMacroArgs = false;

  ArgMacro = nullptr;

  InMacroArgPreExpansion = false;

  NumCachedTokenLexers = 0;

  PragmasEnabled = true;

  ParsingIfOrElifDirective = false;

  PreprocessedOutput = false;

  // We haven't read anything from the external source.

  ReadMacrosFromExternalSource = false;

  BuiltinInfo = std::make_unique<Builtin::Context>();

  // "Poison" __VA_ARGS__, __VA_OPT__ which can only appear in the expansion of

  // a macro. They get unpoisoned where it is allowed.

  (Ident__VA_ARGS__ = getIdentifierInfo("__VA_ARGS__"))->setIsPoisoned();

  SetPoisonReason(Ident__VA_ARGS__,diag::ext_pp_bad_vaargs_use);

  if (getLangOpts().CPlusPlus20) {

    (Ident__VA_OPT__ = getIdentifierInfo("__VA_OPT__"))->setIsPoisoned();

    SetPoisonReason(Ident__VA_OPT__,diag::ext_pp_bad_vaopt_use);

  } else {

    Ident__VA_OPT__ = nullptr;

  }

  // Initialize the pragma handlers.

  RegisterBuiltinPragmas();

  // Initialize builtin macros like __LINE__ and friends.

  RegisterBuiltinMacros();

  if(LangOpts.Borland) {

    Ident__exception_info        = getIdentifierInfo("_exception_info");

    Ident___exception_info       = getIdentifierInfo("__exception_info");

    Ident_GetExceptionInfo       = getIdentifierInfo("GetExceptionInformation");

    Ident__exception_code        = getIdentifierInfo("_exception_code");

    Ident___exception_code       = getIdentifierInfo("__exception_code");

    Ident_GetExceptionCode       = getIdentifierInfo("GetExceptionCode");

    Ident__abnormal_termination  = getIdentifierInfo("_abnormal_termination");

    Ident___abnormal_termination = getIdentifierInfo("__abnormal_termination");

    Ident_AbnormalTermination    = getIdentifierInfo("AbnormalTermination");

  } else {

    Ident__exception_info = Ident__exception_code = nullptr;

    Ident__abnormal_termination = Ident___exception_info = nullptr;

    Ident___exception_code = Ident___abnormal_termination = nullptr;

    Ident_GetExceptionInfo = Ident_GetExceptionCode = nullptr;

    Ident_AbnormalTermination = nullptr;

  }

  // If using a PCH where a #pragma hdrstop is expected, start skipping tokens.

  if (usingPCHWithPragmaHdrStop())

    SkippingUntilPragmaHdrStop = true;

  // If using a PCH with a through header, start skipping tokens.

  if (!this->PPOpts->PCHThroughHeader.empty() &&

      !this->PPOpts->ImplicitPCHInclude.empty())

    SkippingUntilPCHThroughHeader = true;

  if (this->PPOpts->GeneratePreamble)

    PreambleConditionalStack.startRecording();

  ExcludedConditionalDirectiveSkipMappings =

      this->PPOpts->ExcludedConditionalDirectiveSkipMappings;

  if (ExcludedConditionalDirectiveSkipMappings)

    ExcludedConditionalDirectiveSkipMappings->clear();

  MaxTokens = LangOpts.MaxTokens;

}

Preprocessor::~Preprocessor() {

  assert(BacktrackPositions.empty() && "EnableBacktrack/Backtrack imbalance!");

  IncludeMacroStack.clear();

  // Destroy any macro definitions.

  while (MacroInfoChain *I = MIChainHead) {

    MIChainHead = I->Next;

    I->~MacroInfoChain();

  }

  // Free any cached macro expanders.

  // This populates MacroArgCache, so all TokenLexers need to be destroyed

  // before the code below that frees up the MacroArgCache list.

  std::fill(TokenLexerCache, TokenLexerCache + NumCachedTokenLexers, nullptr);

  CurTokenLexer.reset();

  // Free any cached MacroArgs.

  for (MacroArgs *ArgList = MacroArgCache; ArgList;)

    ArgList = ArgList->deallocate();

  // Delete the header search info, if we own it.

  if (OwnsHeaderSearch)

    delete &HeaderInfo;

}

void Preprocessor::Initialize(const TargetInfo &Target,

                              const TargetInfo *AuxTarget) {

  assert((!this->Target || this->Target == &Target) &&

         "Invalid override of target information");

  this->Target = &Target;

  assert((!this->AuxTarget || this->AuxTarget == AuxTarget) &&

         "Invalid override of aux target information.");

  this->AuxTarget = AuxTarget;

  // Initialize information about built-ins.

  BuiltinInfo->InitializeTarget(Target, AuxTarget);

  HeaderInfo.setTarget(Target);

  // Populate the identifier table with info about keywords for the current language.

  Identifiers.AddKeywords(LangOpts);

}

void Preprocessor::InitializeForModelFile() {

  NumEnteredSourceFiles = 0;

  // Reset pragmas

  PragmaHandlersBackup = std::move(PragmaHandlers);

  PragmaHandlers = std::make_unique<PragmaNamespace>(StringRef());

  RegisterBuiltinPragmas();

  // Reset PredefinesFileID

  PredefinesFileID = FileID();

}

void Preprocessor::FinalizeForModelFile() {

  NumEnteredSourceFiles = 1;

  PragmaHandlers = std::move(PragmaHandlersBackup);

}

void Preprocessor::DumpToken(const Token &Tok, bool DumpFlags) const {

  llvm::errs() << tok::getTokenName(Tok.getKind()) << " '"

               << getSpelling(Tok) << "'";

  if (!DumpFlags) 
return0
;

  llvm::errs() << "\t";

  if (Tok.isAtStartOfLine())

    llvm::errs() << " [StartOfLine]";

  if (Tok.hasLeadingSpace())

    llvm::errs() << " [LeadingSpace]";

  if (Tok.isExpandDisabled())

    llvm::errs() << " [ExpandDisabled]";

  if (Tok.needsCleaning()) {

    const char *Start = SourceMgr.getCharacterData(Tok.getLocation());

    llvm::errs() << " [UnClean='" << StringRef(Start, Tok.getLength())

                 << "']";

  }

  llvm::errs() << "\tLoc=<";

  DumpLocation(Tok.getLocation());

  llvm::errs() << ">";

}

void Preprocessor::DumpLocation(SourceLocation Loc) const {

  Loc.print(llvm::errs(), SourceMgr);

}

void Preprocessor::DumpMacro(const MacroInfo &MI) const {

  llvm::errs() << "MACRO: ";

  for (unsigned i = 0, e = MI.getNumTokens(); i != e; ++i) {

    DumpToken(MI.getReplacementToken(i));

    llvm::errs() << "  ";

  }

  llvm::errs() << "\n";

}

void Preprocessor::PrintStats() {

  llvm::errs() << "\n*** Preprocessor Stats:\n";

  llvm::errs() << NumDirectives << " directives found:\n";

  llvm::errs() << "  " << NumDefined << " #define.\n";

  llvm::errs() << "  " << NumUndefined << " #undef.\n";

  llvm::errs() << "  #include/#include_next/#import:\n";

  llvm::errs() << "    " << NumEnteredSourceFiles << " source files entered.\n";

  llvm::errs() << "    " << MaxIncludeStackDepth << " max include stack depth\n";

  llvm::errs() << "  " << NumIf << " #if/#ifndef/#ifdef.\n";

  llvm::errs() << "  " << NumElse << " #else/#elif.\n";

  llvm::errs() << "  " << NumEndif << " #endif.\n";

  llvm::errs() << "  " << NumPragma << " #pragma.\n";

  llvm::errs() << NumSkipped << " #if/#ifndef#ifdef regions skipped\n";

  llvm::errs() << NumMacroExpanded << "/" << NumFnMacroExpanded << "/"

             << NumBuiltinMacroExpanded << " obj/fn/builtin macros expanded, "

             << NumFastMacroExpanded << " on the fast path.\n";

  llvm::errs() << (NumFastTokenPaste+NumTokenPaste)

             << " token paste (##) operations performed, "

             << NumFastTokenPaste << " on the fast path.\n";

  llvm::errs() << "\nPreprocessor Memory: " << getTotalMemory() << "B total";

  llvm::errs() << "\n  BumpPtr: " << BP.getTotalMemory();

  llvm::errs() << "\n  Macro Expanded Tokens: "

               << llvm::capacity_in_bytes(MacroExpandedTokens);

  llvm::errs() << "\n  Predefines Buffer: " << Predefines.capacity();

  // FIXME: List information for all submodules.

  llvm::errs() << "\n  Macros: "

               << llvm::capacity_in_bytes(CurSubmoduleState->Macros);

  llvm::errs() << "\n  #pragma push_macro Info: "

               << llvm::capacity_in_bytes(PragmaPushMacroInfo);

  llvm::errs() << "\n  Poison Reasons: "

               << llvm::capacity_in_bytes(PoisonReasons);

  llvm::errs() << "\n  Comment Handlers: "

               << llvm::capacity_in_bytes(CommentHandlers) << "\n";

}

Preprocessor::macro_iterator

Preprocessor::macro_begin(bool IncludeExternalMacros) const {

  if (IncludeExternalMacros && 
ExternalSource2.38k
 &&

      !ReadMacrosFromExternalSource) {

    ReadMacrosFromExternalSource = true;

    ExternalSource->ReadDefinedMacros();

  }

  // Make sure we cover all macros in visible modules.

  for (const ModuleMacro &Macro : ModuleMacros)

    CurSubmoduleState->Macros.insert(std::make_pair(Macro.II, MacroState()));

  return CurSubmoduleState->Macros.begin();

}

size_t Preprocessor::getTotalMemory() const {

  return BP.getTotalMemory()

    + llvm::capacity_in_bytes(MacroExpandedTokens)

    + Predefines.capacity() /* Predefines buffer. */

    // FIXME: Include sizes from all submodules, and include MacroInfo sizes,

    // and ModuleMacros.

    + llvm::capacity_in_bytes(CurSubmoduleState->Macros)

    + llvm::capacity_in_bytes(PragmaPushMacroInfo)

    + llvm::capacity_in_bytes(PoisonReasons)

    + llvm::capacity_in_bytes(CommentHandlers);

}

Preprocessor::macro_iterator

Preprocessor::macro_end(bool IncludeExternalMacros) const {

  if (IncludeExternalMacros && 
ExternalSource2.38k
 &&

      !ReadMacrosFromExternalSource) {

    ReadMacrosFromExternalSource = true;

    ExternalSource->ReadDefinedMacros();

  }

  return CurSubmoduleState->Macros.end();

}

/// Compares macro tokens with a specified token value sequence.

static bool MacroDefinitionEquals(const MacroInfo *MI,

                                  ArrayRef<TokenValue> Tokens) {

  return Tokens.size() == MI->getNumTokens() &&

      std::equal(Tokens.begin(), Tokens.end(), MI->tokens_begin());

}

StringRef Preprocessor::getLastMacroWithSpelling(

                                    SourceLocation Loc,

                                    ArrayRef<TokenValue> Tokens) const {

  SourceLocation BestLocation;

  StringRef BestSpelling;

  for (Preprocessor::macro_iterator I = macro_begin(), E = macro_end();

       I != E; 
++I114k
) {

    const MacroDirective::DefInfo

      Def = I->second.findDirectiveAtLoc(Loc, SourceMgr);

    if (!Def || 
!Def.getMacroInfo()114k
)

      continue;

    if (!Def.getMacroInfo()->isObjectLike())

      continue;

    if (!MacroDefinitionEquals(Def.getMacroInfo(), Tokens))

      continue;

    SourceLocation Location = Def.getLocation();

    // Choose the macro defined latest.

    if (BestLocation.isInvalid() ||

        (Location.isValid() &&

         
SourceMgr.isBeforeInTranslationUnit(BestLocation, Location)13
)) {

      BestLocation = Location;

      BestSpelling = I->first->getName();

    }

  }

  return BestSpelling;

}

void Preprocessor::recomputeCurLexerKind() {

  if (CurLexer)

    CurLexerKind = CLK_Lexer;

  else if (CurTokenLexer)

    CurLexerKind = CLK_TokenLexer;

  else

    CurLexerKind = CLK_CachingLexer;

}

bool Preprocessor::SetCodeCompletionPoint(const FileEntry *File,

                                          unsigned CompleteLine,

                                          unsigned CompleteColumn) {

  assert(File);

  assert(CompleteLine && CompleteColumn && "Starts from 1:1");

  assert(!CodeCompletionFile && "Already set");

  // Load the actual file's contents.

  Optional<llvm::MemoryBufferRef> Buffer =

      SourceMgr.getMemoryBufferForFileOrNone(File);

  if (!Buffer)

    return true;

  // Find the byte position of the truncation point.

  const char *Position = Buffer->getBufferStart();

  for (unsigned Line = 1; Line < CompleteLine; 
++Line34.5k
) {

    for (; *Position; 
++Position852k
) {

      if (*Position != '\r' && *Position != '\n')

        continue;

      // Eat \r\n or \n\r as a single line.

      if ((Position[1] == '\r' || Position[1] == '\n') &&

          Position[0] != Position[1])

        ++Position;

      ++Position;

      break;

    }

  }

  Position += CompleteColumn - 1;

  // If pointing inside the preamble, adjust the position at the beginning of

  // the file after the preamble.

  if (SkipMainFilePreamble.first &&

      SourceMgr.getFileEntryForID(SourceMgr.getMainFileID()) == File) {

    if (Position - Buffer->getBufferStart() < SkipMainFilePreamble.first)

      Position = Buffer->getBufferStart() + SkipMainFilePreamble.first;

  }

  if (Position > Buffer->getBufferEnd())

    Position = Buffer->getBufferEnd();

  CodeCompletionFile = File;

  CodeCompletionOffset = Position - Buffer->getBufferStart();

  auto NewBuffer = llvm::WritableMemoryBuffer::getNewUninitMemBuffer(

      Buffer->getBufferSize() + 1, Buffer->getBufferIdentifier());

  char *NewBuf = NewBuffer->getBufferStart();

  char *NewPos = std::copy(Buffer->getBufferStart(), Position, NewBuf);

  *NewPos = '\0';

  std::copy(Position, Buffer->getBufferEnd(), NewPos+1);

  SourceMgr.overrideFileContents(File, std::move(NewBuffer));

  return false;

}

void Preprocessor::CodeCompleteIncludedFile(llvm::StringRef Dir,

                                            bool IsAngled) {

  if (CodeComplete)

    CodeComplete->CodeCompleteIncludedFile(Dir, IsAngled);

  setCodeCompletionReached();

}

void Preprocessor::CodeCompleteNaturalLanguage() {

  if (CodeComplete)

    CodeComplete->CodeCompleteNaturalLanguage();

  setCodeCompletionReached();

}

/// getSpelling - This method is used to get the spelling of a token into a

/// SmallVector. Note that the returned StringRef may not point to the

/// supplied buffer if a copy can be avoided.

StringRef Preprocessor::getSpelling(const Token &Tok,

                                          SmallVectorImpl<char> &Buffer,

                                          bool *Invalid) const {

  // NOTE: this has to be checked *before* testing for an IdentifierInfo.

  if (Tok.isNot(tok::raw_identifier) && 
!Tok.hasUCN()12.2M
) {

    // Try the fast path.

    if (const IdentifierInfo *II = Tok.getIdentifierInfo())

      return II->getName();

  }

  // Resize the buffer if we need to copy into it.

  if (Tok.needsCleaning())

    Buffer.resize(Tok.getLength());

  const char *Ptr = Buffer.data();

  unsigned Len = getSpelling(Tok, Ptr, Invalid);

  return StringRef(Ptr, Len);

}

/// CreateString - Plop the specified string into a scratch buffer and return a

/// location for it.  If specified, the source location provides a source

/// location for the token.

void Preprocessor::CreateString(StringRef Str, Token &Tok,

                                SourceLocation ExpansionLocStart,

                                SourceLocation ExpansionLocEnd) {

  Tok.setLength(Str.size());

  const char *DestPtr;

  SourceLocation Loc = ScratchBuf->getToken(Str.data(), Str.size(), DestPtr);

  if (ExpansionLocStart.isValid())

    Loc = SourceMgr.createExpansionLoc(Loc, ExpansionLocStart,

                                       ExpansionLocEnd, Str.size());

  Tok.setLocation(Loc);

  // If this is a raw identifier or a literal token, set the pointer data.

  if (Tok.is(tok::raw_identifier))

    Tok.setRawIdentifierData(DestPtr);

  else if (Tok.isLiteral())

    Tok.setLiteralData(DestPtr);

}

SourceLocation Preprocessor::SplitToken(SourceLocation Loc, unsigned Length) {

  auto &SM = getSourceManager();

  SourceLocation SpellingLoc = SM.getSpellingLoc(Loc);

  std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(SpellingLoc);

  bool Invalid = false;

  StringRef Buffer = SM.getBufferData(LocInfo.first, &Invalid);

  if (Invalid)

    return SourceLocation();

  // FIXME: We could consider re-using spelling for tokens we see repeatedly.

  const char *DestPtr;

  SourceLocation Spelling =

      ScratchBuf->getToken(Buffer.data() + LocInfo.second, Length, DestPtr);

  return SM.createTokenSplitLoc(Spelling, Loc, Loc.getLocWithOffset(Length));

}

Module *Preprocessor::getCurrentModule() {

  if (!getLangOpts().isCompilingModule())

    return nullptr;

  return getHeaderSearchInfo().lookupModule(getLangOpts().CurrentModule);

}

//===----------------------------------------------------------------------===//

// Preprocessor Initialization Methods

//===----------------------------------------------------------------------===//

/// EnterMainSourceFile - Enter the specified FileID as the main source file,

/// which implicitly adds the builtin defines etc.

void Preprocessor::EnterMainSourceFile() {

  // We do not allow the preprocessor to reenter the main file.  Doing so will

  // cause FileID's to accumulate information from both runs (e.g. #line

  // information) and predefined macros aren't guaranteed to be set properly.

  assert(NumEnteredSourceFiles == 0 && "Cannot reenter the main file!");

  FileID MainFileID = SourceMgr.getMainFileID();

  // If MainFileID is loaded it means we loaded an AST file, no need to enter

  // a main file.

  if (!SourceMgr.isLoadedFileID(MainFileID)) {

    // Enter the main file source buffer.

    EnterSourceFile(MainFileID, nullptr, SourceLocation());

    // If we've been asked to skip bytes in the main file (e.g., as part of a

    // precompiled preamble), do so now.

    if (SkipMainFilePreamble.first > 0)

      CurLexer->SetByteOffset(SkipMainFilePreamble.first,

                              SkipMainFilePreamble.second);

    // Tell the header info that the main file was entered.  If the file is later

    // #imported, it won't be re-entered.

    if (const FileEntry *FE = SourceMgr.getFileEntryForID(MainFileID))

      HeaderInfo.IncrementIncludeCount(FE);

  }

  // Preprocess Predefines to populate the initial preprocessor state.

  std::unique_ptr<llvm::MemoryBuffer> SB =

    llvm::MemoryBuffer::getMemBufferCopy(Predefines, "<built-in>");

  assert(SB && "Cannot create predefined source buffer");

  FileID FID = SourceMgr.createFileID(std::move(SB));

  assert(FID.isValid() && "Could not create FileID for predefines?");

  setPredefinesFileID(FID);

  // Start parsing the predefines.

  EnterSourceFile(FID, nullptr, SourceLocation());

  if (!PPOpts->PCHThroughHeader.empty()) {

    // Lookup and save the FileID for the through header. If it isn't found

    // in the search path, it's a fatal error.

    const DirectoryLookup *CurDir;

    Optional<FileEntryRef> File = LookupFile(

        SourceLocation(), PPOpts->PCHThroughHeader,

        /*isAngled=*/false, /*FromDir=*/nullptr, /*FromFile=*/nullptr, CurDir,

        /*SearchPath=*/nullptr, /*RelativePath=*/nullptr,

        /*SuggestedModule=*/nullptr, /*IsMapped=*/nullptr,

        /*IsFrameworkFound=*/nullptr);

    if (!File) {

      Diag(SourceLocation(), diag::err_pp_through_header_not_found)

          << PPOpts->PCHThroughHeader;

      return;

    }

    setPCHThroughHeaderFileID(

        SourceMgr.createFileID(*File, SourceLocation(), SrcMgr::C_User));

  }

  // Skip tokens from the Predefines and if needed the main file.

  if ((usingPCHWithThroughHeader() && 
SkippingUntilPCHThroughHeader15
) ||

      (usingPCHWithPragmaHdrStop() && 
SkippingUntilPragmaHdrStop8
))

    SkipTokensWhileUsingPCH();

}

void Preprocessor::setPCHThroughHeaderFileID(FileID FID) {

  assert(PCHThroughHeaderFileID.isInvalid() &&

         "PCHThroughHeaderFileID already set!");

  PCHThroughHeaderFileID = FID;

}

bool Preprocessor::isPCHThroughHeader(const FileEntry *FE) {

  assert(PCHThroughHeaderFileID.isValid() &&

         "Invalid PCH through header FileID");

  return FE == SourceMgr.getFileEntryForID(PCHThroughHeaderFileID);

}

bool Preprocessor::creatingPCHWithThroughHeader() {

  return TUKind == TU_Prefix && 
!PPOpts->PCHThroughHeader.empty()7.35k
 &&

         PCHThroughHeaderFileID.isValid();

}

bool Preprocessor::usingPCHWithThroughHeader() {

  return TUKind != TU_Prefix && 
!PPOpts->PCHThroughHeader.empty()2.40M
 &&

         PCHThroughHeaderFileID.isValid();

}

bool Preprocessor::creatingPCHWithPragmaHdrStop() {

  return TUKind == TU_Prefix && 
PPOpts->PCHWithHdrStop2
;

}

bool Preprocessor::usingPCHWithPragmaHdrStop() {

  return TUKind != TU_Prefix && 
PPOpts->PCHWithHdrStop157k
;

}

/// Skip tokens until after the #include of the through header or

/// until after a #pragma hdrstop is seen. Tokens in the predefines file

/// and the main file may be skipped. If the end of the predefines file

/// is reached, skipping continues into the main file. If the end of the

/// main file is reached, it's a fatal error.

void Preprocessor::SkipTokensWhileUsingPCH() {

  bool ReachedMainFileEOF = false;

  bool UsingPCHThroughHeader = SkippingUntilPCHThroughHeader;

  bool UsingPragmaHdrStop = SkippingUntilPragmaHdrStop;

  Token Tok;

  while (true) {

    bool InPredefines =

        (CurLexer && 
CurLexer->getFileID() == getPredefinesFileID()193
);

    switch (CurLexerKind) {

    case CLK_Lexer:

      CurLexer->Lex(Tok);

     break;

    case CLK_TokenLexer:

      CurTokenLexer->Lex(Tok);

      break;

    case CLK_CachingLexer:

      CachingLex(Tok);

      break;

    case CLK_LexAfterModuleImport:

      LexAfterModuleImport(Tok);

      break;

    }

    if (Tok.is(tok::eof) && 
!InPredefines4
) {

      ReachedMainFileEOF = true;

      break;

    }

    if (UsingPCHThroughHeader && 
!SkippingUntilPCHThroughHeader61
)

      break;

    if (UsingPragmaHdrStop && 
!SkippingUntilPragmaHdrStop132
)

      break;

  }

  if (ReachedMainFileEOF) {

    if (UsingPCHThroughHeader)

      Diag(SourceLocation(), diag::err_pp_through_header_not_seen)

          << PPOpts->PCHThroughHeader << 1;

    else if (!PPOpts->PCHWithHdrStopCreate)

      Diag(SourceLocation(), diag::err_pp_pragma_hdrstop_not_seen);

  }

}

void Preprocessor::replayPreambleConditionalStack() {

  // Restore the conditional stack from the preamble, if there is one.

  if (PreambleConditionalStack.isReplaying()) {

    assert(CurPPLexer &&

           "CurPPLexer is null when calling replayPreambleConditionalStack.");

    CurPPLexer->setConditionalLevels(PreambleConditionalStack.getStack());

    PreambleConditionalStack.doneReplaying();

    if (PreambleConditionalStack.reachedEOFWhileSkipping())

      SkipExcludedConditionalBlock(

          PreambleConditionalStack.SkipInfo->HashTokenLoc,

          PreambleConditionalStack.SkipInfo->IfTokenLoc,

          PreambleConditionalStack.SkipInfo->FoundNonSkipPortion,

          PreambleConditionalStack.SkipInfo->FoundElse,

          PreambleConditionalStack.SkipInfo->ElseLoc);

  }

}

void Preprocessor::EndSourceFile() {

  // Notify the client that we reached the end of the source file.

  if (Callbacks)

    Callbacks->EndOfMainFile();

}

//===----------------------------------------------------------------------===//

// Lexer Event Handling.

//===----------------------------------------------------------------------===//

/// LookUpIdentifierInfo - Given a tok::raw_identifier token, look up the

/// identifier information for the token and install it into the token,

/// updating the token kind accordingly.

IdentifierInfo *Preprocessor::LookUpIdentifierInfo(Token &Identifier) const {

  assert(!Identifier.getRawIdentifier().empty() && "No raw identifier data!");

  // Look up this token, see if it is a macro, or if it is a language keyword.

  IdentifierInfo *II;

  if (!Identifier.needsCleaning() && 
!Identifier.hasUCN()513M
) {

    // No cleaning needed, just use the characters from the lexed buffer.

    II = getIdentifierInfo(Identifier.getRawIdentifier());

  } else {

    // Cleaning needed, alloca a buffer, clean into it, then use the buffer.

    SmallString<64> IdentifierBuffer;

    StringRef CleanedStr = getSpelling(Identifier, IdentifierBuffer);

    if (Identifier.hasUCN()) {

      SmallString<64> UCNIdentifierBuffer;

      expandUCNs(UCNIdentifierBuffer, CleanedStr);

      II = getIdentifierInfo(UCNIdentifierBuffer);

    } else {

      II = getIdentifierInfo(CleanedStr);

    }

  }

  // Update the token info (identifier info and appropriate token kind).

  Identifier.setIdentifierInfo(II);

  if (getLangOpts().MSVCCompat && 
II->isCPlusPlusOperatorKeyword()9.38M
 &&

      getSourceManager().isInSystemHeader(Identifier.getLocation()))

    Identifier.setKind(tok::identifier);

  else

    Identifier.setKind(II->getTokenID());

  return II;

}

void Preprocessor::SetPoisonReason(IdentifierInfo *II, unsigned DiagID) {

  PoisonReasons[II] = DiagID;

}

void Preprocessor::PoisonSEHIdentifiers(bool Poison) {

  assert(Ident__exception_code && Ident__exception_info);

  assert(Ident___exception_code && Ident___exception_info);

  Ident__exception_code->setIsPoisoned(Poison);

  Ident___exception_code->setIsPoisoned(Poison);

  Ident_GetExceptionCode->setIsPoisoned(Poison);

  Ident__exception_info->setIsPoisoned(Poison);

  Ident___exception_info->setIsPoisoned(Poison);

  Ident_GetExceptionInfo->setIsPoisoned(Poison);

  Ident__abnormal_termination->setIsPoisoned(Poison);

  Ident___abnormal_termination->setIsPoisoned(Poison);

  Ident_AbnormalTermination->setIsPoisoned(Poison);

}

void Preprocessor::HandlePoisonedIdentifier(Token & Identifier) {

  assert(Identifier.getIdentifierInfo() &&

         "Can't handle identifiers without identifier info!");

  llvm::DenseMap<IdentifierInfo*,unsigned>::const_iterator it =

    PoisonReasons.find(Identifier.getIdentifierInfo());

  if(it == PoisonReasons.end())

    Diag(Identifier, diag::err_pp_used_poisoned_id);

  else

    Diag(Identifier,it->second) << Identifier.getIdentifierInfo();

}

/// Returns a diagnostic message kind for reporting a future keyword as

/// appropriate for the identifier and specified language.

static diag::kind getFutureCompatDiagKind(const IdentifierInfo &II,

                                          const LangOptions &LangOpts) {

  assert(II.isFutureCompatKeyword() && "diagnostic should not be needed");

  if (LangOpts.CPlusPlus)

    return llvm::StringSwitch<diag::kind>(II.getName())

#define CXX11_KEYWORD(NAME, FLAGS)                                             \

        .Case(#NAME, diag::warn_cxx11_keyword)

#define CXX20_KEYWORD(NAME, FLAGS)                                             \

        .Case(#NAME, diag::warn_cxx20_keyword)

#include "clang/Basic/TokenKinds.def"

        // char8_t is not modeled as a CXX20_KEYWORD because it's not

        // unconditionally enabled in C++20 mode. (It can be disabled

        // by -fno-char8_t.)

        .Case("char8_t", diag::warn_cxx20_keyword)

        ;

  llvm_unreachable(

      "Keyword not known to come from a newer Standard or proposed Standard");

}

void Preprocessor::updateOutOfDateIdentifier(IdentifierInfo &II) const {

  assert(II.isOutOfDate() && "not out of date");

  getExternalSource()->updateOutOfDateIdentifier(II);

}

/// HandleIdentifier - This callback is invoked when the lexer reads an

/// identifier.  This callback looks up the identifier in the map and/or

/// potentially macro expands it or turns it into a named token (like 'for').

///

/// Note that callers of this method are guarded by checking the

/// IdentifierInfo's 'isHandleIdentifierCase' bit.  If this method changes, the

/// IdentifierInfo methods that compute these properties will need to change to

/// match.

bool Preprocessor::HandleIdentifier(Token &Identifier) {

  assert(Identifier.getIdentifierInfo() &&

         "Can't handle identifiers without identifier info!");

  IdentifierInfo &II = *Identifier.getIdentifierInfo();

  // If the information about this identifier is out of date, update it from

  // the external source.

  // We have to treat __VA_ARGS__ in a special way, since it gets

  // serialized with isPoisoned = true, but our preprocessor may have

  // unpoisoned it if we're defining a C99 macro.

  if (II.isOutOfDate()) {

    bool CurrentIsPoisoned = false;

    const bool IsSpecialVariadicMacro =

        &II == Ident__VA_ARGS__ || 
&II == Ident__VA_OPT__60.1k
;

    if (IsSpecialVariadicMacro)

      CurrentIsPoisoned = II.isPoisoned();

    updateOutOfDateIdentifier(II);

    Identifier.setKind(II.getTokenID());

    if (IsSpecialVariadicMacro)

      II.setIsPoisoned(CurrentIsPoisoned);

  }

  // If this identifier was poisoned, and if it was not produced from a macro

  // expansion, emit an error.

  if (II.isPoisoned() && 
CurPPLexer27.7k
) {

    HandlePoisonedIdentifier(Identifier);

  }

  // If this is a macro to be expanded, do it.

  if (MacroDefinition MD = getMacroDefinition(&II)) {

    auto *MI = MD.getMacroInfo();

    assert(MI && "macro definition with no macro info?");

    if (!DisableMacroExpansion) {

      if (!Identifier.isExpandDisabled() && 
MI->isEnabled()92.8M
) {

        // C99 6.10.3p10: If the preprocessing token immediately after the

        // macro name isn't a '(', this macro should not be expanded.

        if (!MI->isFunctionLike() || 
isNextPPTokenLParen()53.2M
)

          return HandleMacroExpandedIdentifier(Identifier, MD);

      } else {

        // C99 6.10.3.4p2 says that a disabled macro may never again be

        // expanded, even if it's in a context where it could be expanded in the

        // future.

        Identifier.setFlag(Token::DisableExpand);

        if (MI->isObjectLike() || 
isNextPPTokenLParen()574
)

          Diag(Identifier, diag::pp_disabled_macro_expansion);

      }

    }

  }

  // If this identifier is a keyword in a newer Standard or proposed Standard,

  // produce a warning. Don't warn if we're not considering macro expansion,

  // since this identifier might be the name of a macro.

  // FIXME: This warning is disabled in cases where it shouldn't be, like

  //   "#define constexpr constexpr", "int constexpr;"

  if (II.isFutureCompatKeyword() && 
!DisableMacroExpansion1.00k
) {

    Diag(Identifier, getFutureCompatDiagKind(II, getLangOpts()))

        << II.getName();

    // Don't diagnose this keyword again in this translation unit.

    II.setIsFutureCompatKeyword(false);

  }

  // If this is an extension token, diagnose its use.

  // We avoid diagnosing tokens that originate from macro definitions.

  // FIXME: This warning is disabled in cases where it shouldn't be,

  // like "#define TY typeof", "TY(1) x".

  if (II.isExtensionToken() && 
!DisableMacroExpansion7.61k
)

    Diag(Identifier, diag::ext_token_used);

  // If this is the 'import' contextual keyword following an '@', note

  // that the next token indicates a module name.

  //

  // Note that we do not treat 'import' as a contextual

  // keyword when we're in a caching lexer, because caching lexers only get

  // used in contexts where import declarations are disallowed.

  //

  // Likewise if this is the C++ Modules TS import keyword.

  if (((LastTokenWasAt && 
II.isModulesImport()3.12k
) ||

       Identifier.is(tok::kw_import)) &&

      !InMacroArgs && 
!DisableMacroExpansion1.72k
 &&

      (getLangOpts().Modules || 
getLangOpts().DebuggerSupport41
) &&

      CurLexerKind != CLK_CachingLexer) {

    ModuleImportLoc = Identifier.getLocation();

    ModuleImportPath.clear();

    ModuleImportExpectsIdentifier = true;

    CurLexerKind = CLK_LexAfterModuleImport;

  }

  return true;

}

void Preprocessor::Lex(Token &Result) {

  ++LexLevel;

  // We loop here until a lex function returns a token; this avoids recursion.

  bool ReturnedToken;

  do {

    switch (CurLexerKind) {

    case CLK_Lexer:

      ReturnedToken = CurLexer->Lex(Result);

      break;

    case CLK_TokenLexer:

      ReturnedToken = CurTokenLexer->Lex(Result);

      break;

    case CLK_CachingLexer:

      CachingLex(Result);

      ReturnedToken = true;

      break;

    case CLK_LexAfterModuleImport:

      ReturnedToken = LexAfterModuleImport(Result);

      break;

    }

  } while (!ReturnedToken);

  if (Result.is(tok::unknown) && 
TheModuleLoader.HadFatalFailure13.9k
)

    return;

  if (Result.is(tok::code_completion) && 
Result.getIdentifierInfo()3.29k
) {

    // Remember the identifier before code completion token.

    setCodeCompletionIdentifierInfo(Result.getIdentifierInfo());

    setCodeCompletionTokenRange(Result.getLocation(), Result.getEndLoc());

    // Set IdenfitierInfo to null to avoid confusing code that handles both

    // identifiers and completion tokens.

    Result.setIdentifierInfo(nullptr);

  }

  // Update ImportSeqState to track our position within a C++20 import-seq

  // if this token is being produced as a result of phase 4 of translation.

  if (getLangOpts().CPlusPlusModules && 
LexLevel == 15.91M
 &&

      !Result.getFlag(Token::IsReinjected)) {

    switch (Result.getKind()) {

    case tok::l_paren: case tok::l_square: case tok::l_brace:

      ImportSeqState.handleOpenBracket();

      break;

    case tok::r_paren: case tok::r_square:

      ImportSeqState.handleCloseBracket();

      break;

    case tok::r_brace:

      ImportSeqState.handleCloseBrace();

      break;

    case tok::semi:

      ImportSeqState.handleSemi();

      break;

    case tok::header_name:

    case tok::annot_header_unit:

      ImportSeqState.handleHeaderName();

      break;

    case tok::kw_export:

      ImportSeqState.handleExport();

      break;

    case tok::identifier:

      if (Result.getIdentifierInfo()->isModulesImport()) {

        ImportSeqState.handleImport();

        if (ImportSeqState.afterImportSeq()) {

          ModuleImportLoc = Result.getLocation();

          ModuleImportPath.clear();

          ModuleImportExpectsIdentifier = true;

          CurLexerKind = CLK_LexAfterModuleImport;

        }

        break;

      }

      LLVM_FALLTHROUGH;

    default:

      ImportSeqState.handleMisc();

      break;

    }

  }

  LastTokenWasAt = Result.is(tok::at);

  --LexLevel;

  if ((LexLevel == 0 || 
PreprocessToken1.13G
) &&

      !Result.getFlag(Token::IsReinjected)) {

    if (LexLevel == 0)

      ++TokenCount;

    if (OnToken)

      OnToken(Result);

  }

}

/// Lex a header-name token (including one formed from header-name-tokens if

/// \p AllowConcatenation is \c true).

///

/// \param FilenameTok Filled in with the next token. On success, this will

///        be either a header_name token. On failure, it will be whatever other

///        token was found instead.

/// \param AllowMacroExpansion If \c true, allow the header name to be formed

///        by macro expansion (concatenating tokens as necessary if the first

///        token is a '<').

/// \return \c true if we reached EOD or EOF while looking for a > token in

///         a concatenated header name and diagnosed it. \c false otherwise.

bool Preprocessor::LexHeaderName(Token &FilenameTok, bool AllowMacroExpansion) {

  // Lex using header-name tokenization rules if tokens are being lexed from

  // a file. Just grab a token normally if we're in a macro expansion.

  if (CurPPLexer)

    CurPPLexer->LexIncludeFilename(FilenameTok);

  else

    Lex(FilenameTok);

  // This could be a <foo/bar.h> file coming from a macro expansion.  In this

  // case, glue the tokens together into an angle_string_literal token.

  SmallString<128> FilenameBuffer;

  if (FilenameTok.is(tok::less) && 
AllowMacroExpansion23
) {

    bool StartOfLine = FilenameTok.isAtStartOfLine();

    bool LeadingSpace = FilenameTok.hasLeadingSpace();

    bool LeadingEmptyMacro = FilenameTok.hasLeadingEmptyMacro();

    SourceLocation Start = FilenameTok.getLocation();

    SourceLocation End;

    FilenameBuffer.push_back('<');

    // Consume tokens until we find a '>'.

    // FIXME: A header-name could be formed starting or ending with an

    // alternative token. It's not clear whether that's ill-formed in all

    // cases.

    while (FilenameTok.isNot(tok::greater)) {

      Lex(FilenameTok);

      if (FilenameTok.isOneOf(tok::eod, tok::eof)) {

        Diag(FilenameTok.getLocation(), diag::err_expected) << tok::greater;

        Diag(Start, diag::note_matching) << tok::less;

        return true;

      }

      End = FilenameTok.getLocation();

      // FIXME: Provide code completion for #includes.

      if (FilenameTok.is(tok::code_completion)) {

        setCodeCompletionReached();

        Lex(FilenameTok);

        continue;

      }