YQ Connector: support managed ClickHouse

Со стороны dqrun можно обратиться к инстансу коннектора, который работает на streaming стенде, и извлечь данные из облачного CH.

1 files changed, 2192 insertions, 0 deletions

diff --git a/contrib/libs/clang14/lib/Lex/Pragma.cpp b/contrib/libs/clang14/lib/Lex/Pragma.cpp
new file mode 100644
index 0000000000..eb7e7cbc47
--- /dev/null
+++ b/contrib/libs/clang14/lib/Lex/Pragma.cpp
@@ -0,0 +1,2192 @@
+//===- Pragma.cpp - Pragma registration and handling ----------------------===//
+//
+// 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 PragmaHandler/PragmaTable interfaces and implements
+// pragma related methods of the Preprocessor class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Lex/Pragma.h"
+#include "clang/Basic/CLWarnings.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticLex.h"
+#include "clang/Basic/FileManager.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/TokenKinds.h"
+#include "clang/Lex/HeaderSearch.h"
+#include "clang/Lex/LexDiagnostic.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Lex/LiteralSupport.h"
+#include "clang/Lex/MacroInfo.h"
+#include "clang/Lex/ModuleLoader.h"
+#include "clang/Lex/PPCallbacks.h"
+#include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/PreprocessorLexer.h"
+#include "clang/Lex/PreprocessorOptions.h"
+#include "clang/Lex/Token.h"
+#include "clang/Lex/TokenLexer.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Optional.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/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/Timer.h"
+#include <algorithm>
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <limits>
+#include <string>
+#include <utility>
+#include <vector>
+
+using namespace clang;
+
+// Out-of-line destructor to provide a home for the class.
+PragmaHandler::~PragmaHandler() = default;
+
+//===----------------------------------------------------------------------===//
+// EmptyPragmaHandler Implementation.
+//===----------------------------------------------------------------------===//
+
+EmptyPragmaHandler::EmptyPragmaHandler(StringRef Name) : PragmaHandler(Name) {}
+
+void EmptyPragmaHandler::HandlePragma(Preprocessor &PP,
+                                      PragmaIntroducer Introducer,
+                                      Token &FirstToken) {}
+
+//===----------------------------------------------------------------------===//
+// PragmaNamespace Implementation.
+//===----------------------------------------------------------------------===//
+
+/// FindHandler - Check to see if there is already a handler for the
+/// specified name.  If not, return the handler for the null identifier if it
+/// exists, otherwise return null.  If IgnoreNull is true (the default) then
+/// the null handler isn't returned on failure to match.
+PragmaHandler *PragmaNamespace::FindHandler(StringRef Name,
+                                            bool IgnoreNull) const {
+  auto I = Handlers.find(Name);
+  if (I != Handlers.end())
+    return I->getValue().get();
+  if (IgnoreNull)
+    return nullptr;
+  I = Handlers.find(StringRef());
+  if (I != Handlers.end())
+    return I->getValue().get();
+  return nullptr;
+}
+
+void PragmaNamespace::AddPragma(PragmaHandler *Handler) {
+  assert(!Handlers.count(Handler->getName()) &&
+         "A handler with this name is already registered in this namespace");
+  Handlers[Handler->getName()].reset(Handler);
+}
+
+void PragmaNamespace::RemovePragmaHandler(PragmaHandler *Handler) {
+  auto I = Handlers.find(Handler->getName());
+  assert(I != Handlers.end() &&
+         "Handler not registered in this namespace");
+  // Release ownership back to the caller.
+  I->getValue().release();
+  Handlers.erase(I);
+}
+
+void PragmaNamespace::HandlePragma(Preprocessor &PP,
+                                   PragmaIntroducer Introducer, Token &Tok) {
+  // Read the 'namespace' that the directive is in, e.g. STDC.  Do not macro
+  // expand it, the user can have a STDC #define, that should not affect this.
+  PP.LexUnexpandedToken(Tok);
+
+  // Get the handler for this token.  If there is no handler, ignore the pragma.
+  PragmaHandler *Handler
+    = FindHandler(Tok.getIdentifierInfo() ? Tok.getIdentifierInfo()->getName()
+                                          : StringRef(),
+                  /*IgnoreNull=*/false);
+  if (!Handler) {
+    PP.Diag(Tok, diag::warn_pragma_ignored);
+    return;
+  }
+
+  // Otherwise, pass it down.
+  Handler->HandlePragma(PP, Introducer, Tok);
+}
+
+//===----------------------------------------------------------------------===//
+// Preprocessor Pragma Directive Handling.
+//===----------------------------------------------------------------------===//
+
+namespace {
+// TokenCollector provides the option to collect tokens that were "read"
+// and return them to the stream to be read later.
+// Currently used when reading _Pragma/__pragma directives.
+struct TokenCollector {
+  Preprocessor &Self;
+  bool Collect;
+  SmallVector<Token, 3> Tokens;
+  Token &Tok;
+
+  void lex() {
+    if (Collect)
+      Tokens.push_back(Tok);
+    Self.Lex(Tok);
+  }
+
+  void revert() {
+    assert(Collect && "did not collect tokens");
+    assert(!Tokens.empty() && "collected unexpected number of tokens");
+
+    // Push the ( "string" ) tokens into the token stream.
+    auto Toks = std::make_unique<Token[]>(Tokens.size());
+    std::copy(Tokens.begin() + 1, Tokens.end(), Toks.get());
+    Toks[Tokens.size() - 1] = Tok;
+    Self.EnterTokenStream(std::move(Toks), Tokens.size(),
+                          /*DisableMacroExpansion*/ true,
+                          /*IsReinject*/ true);
+
+    // ... and return the pragma token unchanged.
+    Tok = *Tokens.begin();
+  }
+};
+} // namespace
+
+/// HandlePragmaDirective - The "\#pragma" directive has been parsed.  Lex the
+/// rest of the pragma, passing it to the registered pragma handlers.
+void Preprocessor::HandlePragmaDirective(PragmaIntroducer Introducer) {
+  if (Callbacks)
+    Callbacks->PragmaDirective(Introducer.Loc, Introducer.Kind);
+
+  if (!PragmasEnabled)
+    return;
+
+  ++NumPragma;
+
+  // Invoke the first level of pragma handlers which reads the namespace id.
+  Token Tok;
+  PragmaHandlers->HandlePragma(*this, Introducer, Tok);
+
+  // If the pragma handler didn't read the rest of the line, consume it now.
+  if ((CurTokenLexer && CurTokenLexer->isParsingPreprocessorDirective())
+   || (CurPPLexer && CurPPLexer->ParsingPreprocessorDirective))
+    DiscardUntilEndOfDirective();
+}
+
+/// Handle_Pragma - Read a _Pragma directive, slice it up, process it, then
+/// return the first token after the directive.  The _Pragma token has just
+/// been read into 'Tok'.
+void Preprocessor::Handle_Pragma(Token &Tok) {
+  // C11 6.10.3.4/3:
+  //   all pragma unary operator expressions within [a completely
+  //   macro-replaced preprocessing token sequence] are [...] processed [after
+  //   rescanning is complete]
+  //
+  // This means that we execute _Pragma operators in two cases:
+  //
+  //  1) on token sequences that would otherwise be produced as the output of
+  //     phase 4 of preprocessing, and
+  //  2) on token sequences formed as the macro-replaced token sequence of a
+  //     macro argument
+  //
+  // Case #2 appears to be a wording bug: only _Pragmas that would survive to
+  // the end of phase 4 should actually be executed. Discussion on the WG14
+  // mailing list suggests that a _Pragma operator is notionally checked early,
+  // but only pragmas that survive to the end of phase 4 should be executed.
+  //
+  // In Case #2, we check the syntax now, but then put the tokens back into the
+  // token stream for later consumption.
+
+  TokenCollector Toks = {*this, InMacroArgPreExpansion, {}, Tok};
+
+  // Remember the pragma token location.
+  SourceLocation PragmaLoc = Tok.getLocation();
+
+  // Read the '('.
+  Toks.lex();
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(PragmaLoc, diag::err__Pragma_malformed);
+    return;
+  }
+
+  // Read the '"..."'.
+  Toks.lex();
+  if (!tok::isStringLiteral(Tok.getKind())) {
+    Diag(PragmaLoc, diag::err__Pragma_malformed);
+    // Skip bad tokens, and the ')', if present.
+    if (Tok.isNot(tok::r_paren) && Tok.isNot(tok::eof))
+      Lex(Tok);
+    while (Tok.isNot(tok::r_paren) &&
+           !Tok.isAtStartOfLine() &&
+           Tok.isNot(tok::eof))
+      Lex(Tok);
+    if (Tok.is(tok::r_paren))
+      Lex(Tok);
+    return;
+  }
+
+  if (Tok.hasUDSuffix()) {
+    Diag(Tok, diag::err_invalid_string_udl);
+    // Skip this token, and the ')', if present.
+    Lex(Tok);
+    if (Tok.is(tok::r_paren))
+      Lex(Tok);
+    return;
+  }
+
+  // Remember the string.
+  Token StrTok = Tok;
+
+  // Read the ')'.
+  Toks.lex();
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(PragmaLoc, diag::err__Pragma_malformed);
+    return;
+  }
+
+  // If we're expanding a macro argument, put the tokens back.
+  if (InMacroArgPreExpansion) {
+    Toks.revert();
+    return;
+  }
+
+  SourceLocation RParenLoc = Tok.getLocation();
+  std::string StrVal = getSpelling(StrTok);
+
+  // The _Pragma is lexically sound.  Destringize according to C11 6.10.9.1:
+  // "The string literal is destringized by deleting any encoding prefix,
+  // deleting the leading and trailing double-quotes, replacing each escape
+  // sequence \" by a double-quote, and replacing each escape sequence \\ by a
+  // single backslash."
+  if (StrVal[0] == 'L' || StrVal[0] == 'U' ||
+      (StrVal[0] == 'u' && StrVal[1] != '8'))
+    StrVal.erase(StrVal.begin());
+  else if (StrVal[0] == 'u')
+    StrVal.erase(StrVal.begin(), StrVal.begin() + 2);
+
+  if (StrVal[0] == 'R') {
+    // FIXME: C++11 does not specify how to handle raw-string-literals here.
+    // We strip off the 'R', the quotes, the d-char-sequences, and the parens.
+    assert(StrVal[1] == '"' && StrVal[StrVal.size() - 1] == '"' &&
+           "Invalid raw string token!");
+
+    // Measure the length of the d-char-sequence.
+    unsigned NumDChars = 0;
+    while (StrVal[2 + NumDChars] != '(') {
+      assert(NumDChars < (StrVal.size() - 5) / 2 &&
+             "Invalid raw string token!");
+      ++NumDChars;
+    }
+    assert(StrVal[StrVal.size() - 2 - NumDChars] == ')');
+
+    // Remove 'R " d-char-sequence' and 'd-char-sequence "'. We'll replace the
+    // parens below.
+    StrVal.erase(0, 2 + NumDChars);
+    StrVal.erase(StrVal.size() - 1 - NumDChars);
+  } else {
+    assert(StrVal[0] == '"' && StrVal[StrVal.size()-1] == '"' &&
+           "Invalid string token!");
+
+    // Remove escaped quotes and escapes.
+    unsigned ResultPos = 1;
+    for (size_t i = 1, e = StrVal.size() - 1; i != e; ++i) {
+      // Skip escapes.  \\ -> '\' and \" -> '"'.
+      if (StrVal[i] == '\\' && i + 1 < e &&
+          (StrVal[i + 1] == '\\' || StrVal[i + 1] == '"'))
+        ++i;
+      StrVal[ResultPos++] = StrVal[i];
+    }
+    StrVal.erase(StrVal.begin() + ResultPos, StrVal.end() - 1);
+  }
+
+  // Remove the front quote, replacing it with a space, so that the pragma
+  // contents appear to have a space before them.
+  StrVal[0] = ' ';
+
+  // Replace the terminating quote with a \n.
+  StrVal[StrVal.size()-1] = '\n';
+
+  // Plop the string (including the newline and trailing null) into a buffer
+  // where we can lex it.
+  Token TmpTok;
+  TmpTok.startToken();
+  CreateString(StrVal, TmpTok);
+  SourceLocation TokLoc = TmpTok.getLocation();
+
+  // Make and enter a lexer object so that we lex and expand the tokens just
+  // like any others.
+  Lexer *TL = Lexer::Create_PragmaLexer(TokLoc, PragmaLoc, RParenLoc,
+                                        StrVal.size(), *this);
+
+  EnterSourceFileWithLexer(TL, nullptr);
+
+  // With everything set up, lex this as a #pragma directive.
+  HandlePragmaDirective({PIK__Pragma, PragmaLoc});
+
+  // Finally, return whatever came after the pragma directive.
+  return Lex(Tok);
+}
+
+/// HandleMicrosoft__pragma - Like Handle_Pragma except the pragma text
+/// is not enclosed within a string literal.
+void Preprocessor::HandleMicrosoft__pragma(Token &Tok) {
+  // During macro pre-expansion, check the syntax now but put the tokens back
+  // into the token stream for later consumption. Same as Handle_Pragma.
+  TokenCollector Toks = {*this, InMacroArgPreExpansion, {}, Tok};
+
+  // Remember the pragma token location.
+  SourceLocation PragmaLoc = Tok.getLocation();
+
+  // Read the '('.
+  Toks.lex();
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(PragmaLoc, diag::err__Pragma_malformed);
+    return;
+  }
+
+  // Get the tokens enclosed within the __pragma(), as well as the final ')'.
+  SmallVector<Token, 32> PragmaToks;
+  int NumParens = 0;
+  Toks.lex();
+  while (Tok.isNot(tok::eof)) {
+    PragmaToks.push_back(Tok);
+    if (Tok.is(tok::l_paren))
+      NumParens++;
+    else if (Tok.is(tok::r_paren) && NumParens-- == 0)
+      break;
+    Toks.lex();
+  }
+
+  if (Tok.is(tok::eof)) {
+    Diag(PragmaLoc, diag::err_unterminated___pragma);
+    return;
+  }
+
+  // If we're expanding a macro argument, put the tokens back.
+  if (InMacroArgPreExpansion) {
+    Toks.revert();
+    return;
+  }
+
+  PragmaToks.front().setFlag(Token::LeadingSpace);
+
+  // Replace the ')' with an EOD to mark the end of the pragma.
+  PragmaToks.back().setKind(tok::eod);
+
+  Token *TokArray = new Token[PragmaToks.size()];
+  std::copy(PragmaToks.begin(), PragmaToks.end(), TokArray);
+
+  // Push the tokens onto the stack.
+  EnterTokenStream(TokArray, PragmaToks.size(), true, true,
+                   /*IsReinject*/ false);
+
+  // With everything set up, lex this as a #pragma directive.
+  HandlePragmaDirective({PIK___pragma, PragmaLoc});
+
+  // Finally, return whatever came after the pragma directive.
+  return Lex(Tok);
+}
+
+/// HandlePragmaOnce - Handle \#pragma once.  OnceTok is the 'once'.
+void Preprocessor::HandlePragmaOnce(Token &OnceTok) {
+  // Don't honor the 'once' when handling the primary source file, unless
+  // this is a prefix to a TU, which indicates we're generating a PCH file, or
+  // when the main file is a header (e.g. when -xc-header is provided on the
+  // commandline).
+  if (isInPrimaryFile() && TUKind != TU_Prefix && !getLangOpts().IsHeaderFile) {
+    Diag(OnceTok, diag::pp_pragma_once_in_main_file);
+    return;
+  }
+
+  // Get the current file lexer we're looking at.  Ignore _Pragma 'files' etc.
+  // Mark the file as a once-only file now.
+  HeaderInfo.MarkFileIncludeOnce(getCurrentFileLexer()->getFileEntry());
+}
+
+void Preprocessor::HandlePragmaMark(Token &MarkTok) {
+  assert(CurPPLexer && "No current lexer?");
+
+  SmallString<64> Buffer;
+  CurLexer->ReadToEndOfLine(&Buffer);
+  if (Callbacks)
+    Callbacks->PragmaMark(MarkTok.getLocation(), Buffer);
+}
+
+/// HandlePragmaPoison - Handle \#pragma GCC poison.  PoisonTok is the 'poison'.
+void Preprocessor::HandlePragmaPoison() {
+  Token Tok;
+
+  while (true) {
+    // Read the next token to poison.  While doing this, pretend that we are
+    // skipping while reading the identifier to poison.
+    // This avoids errors on code like:
+    //   #pragma GCC poison X
+    //   #pragma GCC poison X
+    if (CurPPLexer) CurPPLexer->LexingRawMode = true;
+    LexUnexpandedToken(Tok);
+    if (CurPPLexer) CurPPLexer->LexingRawMode = false;
+
+    // If we reached the end of line, we're done.
+    if (Tok.is(tok::eod)) return;
+
+    // Can only poison identifiers.
+    if (Tok.isNot(tok::raw_identifier)) {
+      Diag(Tok, diag::err_pp_invalid_poison);
+      return;
+    }
+
+    // Look up the identifier info for the token.  We disabled identifier lookup
+    // by saying we're skipping contents, so we need to do this manually.
+    IdentifierInfo *II = LookUpIdentifierInfo(Tok);
+
+    // Already poisoned.
+    if (II->isPoisoned()) continue;
+
+    // If this is a macro identifier, emit a warning.
+    if (isMacroDefined(II))
+      Diag(Tok, diag::pp_poisoning_existing_macro);
+
+    // Finally, poison it!
+    II->setIsPoisoned();
+    if (II->isFromAST())
+      II->setChangedSinceDeserialization();
+  }
+}
+
+/// HandlePragmaSystemHeader - Implement \#pragma GCC system_header.  We know
+/// that the whole directive has been parsed.
+void Preprocessor::HandlePragmaSystemHeader(Token &SysHeaderTok) {
+  if (isInPrimaryFile()) {
+    Diag(SysHeaderTok, diag::pp_pragma_sysheader_in_main_file);
+    return;
+  }
+
+  // Get the current file lexer we're looking at.  Ignore _Pragma 'files' etc.
+  PreprocessorLexer *TheLexer = getCurrentFileLexer();
+
+  // Mark the file as a system header.
+  HeaderInfo.MarkFileSystemHeader(TheLexer->getFileEntry());
+
+  PresumedLoc PLoc = SourceMgr.getPresumedLoc(SysHeaderTok.getLocation());
+  if (PLoc.isInvalid())
+    return;
+
+  unsigned FilenameID = SourceMgr.getLineTableFilenameID(PLoc.getFilename());
+
+  // Notify the client, if desired, that we are in a new source file.
+  if (Callbacks)
+    Callbacks->FileChanged(SysHeaderTok.getLocation(),
+                           PPCallbacks::SystemHeaderPragma, SrcMgr::C_System);
+
+  // Emit a line marker.  This will change any source locations from this point
+  // forward to realize they are in a system header.
+  // Create a line note with this information.
+  SourceMgr.AddLineNote(SysHeaderTok.getLocation(), PLoc.getLine() + 1,
+                        FilenameID, /*IsEntry=*/false, /*IsExit=*/false,
+                        SrcMgr::C_System);
+}
+
+static llvm::Optional<Token> LexHeader(Preprocessor &PP,
+                                       Optional<FileEntryRef> &File,
+                                       bool SuppressIncludeNotFoundError) {
+  Token FilenameTok;
+  if (PP.LexHeaderName(FilenameTok, /*AllowConcatenation*/ false))
+    return llvm::None;
+
+  // If the next token wasn't a header-name, diagnose the error.
+  if (FilenameTok.isNot(tok::header_name)) {
+    PP.Diag(FilenameTok.getLocation(), diag::err_pp_expects_filename);
+    return llvm::None;
+  }
+
+  // Reserve a buffer to get the spelling.
+  SmallString<128> FilenameBuffer;
+  bool Invalid = false;
+  StringRef Filename = PP.getSpelling(FilenameTok, FilenameBuffer, &Invalid);
+  if (Invalid)
+    return llvm::None;
+
+  bool isAngled =
+      PP.GetIncludeFilenameSpelling(FilenameTok.getLocation(), Filename);
+  // If GetIncludeFilenameSpelling set the start ptr to null, there was an
+  // error.
+  if (Filename.empty())
+    return llvm::None;
+
+  // Search include directories for this file.
+  File = PP.LookupFile(FilenameTok.getLocation(), Filename, isAngled, nullptr,
+                       nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
+                       nullptr);
+  if (!File) {
+    if (!SuppressIncludeNotFoundError)
+      PP.Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
+    return llvm::None;
+  }
+
+  return FilenameTok;
+}
+
+/// HandlePragmaIncludeInstead - Handle \#pragma clang include_instead(header).
+void Preprocessor::HandlePragmaIncludeInstead(Token &Tok) {
+  // Get the current file lexer we're looking at.  Ignore _Pragma 'files' etc.
+  PreprocessorLexer *TheLexer = getCurrentFileLexer();
+
+  if (!SourceMgr.isInSystemHeader(Tok.getLocation())) {
+    Diag(Tok, diag::err_pragma_include_instead_not_sysheader);
+    return;
+  }
+
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(Tok, diag::err_expected) << "(";
+    return;
+  }
+
+  Optional<FileEntryRef> File;
+  llvm::Optional<Token> FilenameTok =
+      LexHeader(*this, File, SuppressIncludeNotFoundError);
+  if (!FilenameTok)
+    return;
+
+  Lex(Tok);
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(Tok, diag::err_expected) << ")";
+    return;
+  }
+
+  SmallString<128> FilenameBuffer;
+  StringRef Filename = getSpelling(*FilenameTok, FilenameBuffer);
+  HeaderInfo.AddFileAlias(TheLexer->getFileEntry(), Filename);
+}
+
+/// HandlePragmaDependency - Handle \#pragma GCC dependency "foo" blah.
+void Preprocessor::HandlePragmaDependency(Token &DependencyTok) {
+  Optional<FileEntryRef> File;
+  llvm::Optional<Token> FilenameTok =
+      LexHeader(*this, File, SuppressIncludeNotFoundError);
+  if (!FilenameTok)
+    return;
+
+  const FileEntry *CurFile = getCurrentFileLexer()->getFileEntry();
+
+  // If this file is older than the file it depends on, emit a diagnostic.
+  if (CurFile && CurFile->getModificationTime() < File->getModificationTime()) {
+    // Lex tokens at the end of the message and include them in the message.
+    std::string Message;
+    Lex(DependencyTok);
+    while (DependencyTok.isNot(tok::eod)) {
+      Message += getSpelling(DependencyTok) + " ";
+      Lex(DependencyTok);
+    }
+
+    // Remove the trailing ' ' if present.
+    if (!Message.empty())
+      Message.erase(Message.end()-1);
+    Diag(*FilenameTok, diag::pp_out_of_date_dependency) << Message;
+  }
+}
+
+/// ParsePragmaPushOrPopMacro - Handle parsing of pragma push_macro/pop_macro.
+/// Return the IdentifierInfo* associated with the macro to push or pop.
+IdentifierInfo *Preprocessor::ParsePragmaPushOrPopMacro(Token &Tok) {
+  // Remember the pragma token location.
+  Token PragmaTok = Tok;
+
+  // Read the '('.
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(PragmaTok.getLocation(), diag::err_pragma_push_pop_macro_malformed)
+      << getSpelling(PragmaTok);
+    return nullptr;
+  }
+
+  // Read the macro name string.
+  Lex(Tok);
+  if (Tok.isNot(tok::string_literal)) {
+    Diag(PragmaTok.getLocation(), diag::err_pragma_push_pop_macro_malformed)
+      << getSpelling(PragmaTok);
+    return nullptr;
+  }
+
+  if (Tok.hasUDSuffix()) {
+    Diag(Tok, diag::err_invalid_string_udl);
+    return nullptr;
+  }
+
+  // Remember the macro string.
+  std::string StrVal = getSpelling(Tok);
+
+  // Read the ')'.
+  Lex(Tok);
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(PragmaTok.getLocation(), diag::err_pragma_push_pop_macro_malformed)
+      << getSpelling(PragmaTok);
+    return nullptr;
+  }
+
+  assert(StrVal[0] == '"' && StrVal[StrVal.size()-1] == '"' &&
+         "Invalid string token!");
+
+  // Create a Token from the string.
+  Token MacroTok;
+  MacroTok.startToken();
+  MacroTok.setKind(tok::raw_identifier);
+  CreateString(StringRef(&StrVal[1], StrVal.size() - 2), MacroTok);
+
+  // Get the IdentifierInfo of MacroToPushTok.
+  return LookUpIdentifierInfo(MacroTok);
+}
+
+/// Handle \#pragma push_macro.
+///
+/// The syntax is:
+/// \code
+///   #pragma push_macro("macro")
+/// \endcode
+void Preprocessor::HandlePragmaPushMacro(Token &PushMacroTok) {
+  // Parse the pragma directive and get the macro IdentifierInfo*.
+  IdentifierInfo *IdentInfo = ParsePragmaPushOrPopMacro(PushMacroTok);
+  if (!IdentInfo) return;
+
+  // Get the MacroInfo associated with IdentInfo.
+  MacroInfo *MI = getMacroInfo(IdentInfo);
+
+  if (MI) {
+    // Allow the original MacroInfo to be redefined later.
+    MI->setIsAllowRedefinitionsWithoutWarning(true);
+  }
+
+  // Push the cloned MacroInfo so we can retrieve it later.
+  PragmaPushMacroInfo[IdentInfo].push_back(MI);
+}
+
+/// Handle \#pragma pop_macro.
+///
+/// The syntax is:
+/// \code
+///   #pragma pop_macro("macro")
+/// \endcode
+void Preprocessor::HandlePragmaPopMacro(Token &PopMacroTok) {
+  SourceLocation MessageLoc = PopMacroTok.getLocation();
+
+  // Parse the pragma directive and get the macro IdentifierInfo*.
+  IdentifierInfo *IdentInfo = ParsePragmaPushOrPopMacro(PopMacroTok);
+  if (!IdentInfo) return;
+
+  // Find the vector<MacroInfo*> associated with the macro.
+  llvm::DenseMap<IdentifierInfo *, std::vector<MacroInfo *>>::iterator iter =
+    PragmaPushMacroInfo.find(IdentInfo);
+  if (iter != PragmaPushMacroInfo.end()) {
+    // Forget the MacroInfo currently associated with IdentInfo.
+    if (MacroInfo *MI = getMacroInfo(IdentInfo)) {
+      if (MI->isWarnIfUnused())
+        WarnUnusedMacroLocs.erase(MI->getDefinitionLoc());
+      appendMacroDirective(IdentInfo, AllocateUndefMacroDirective(MessageLoc));
+    }
+
+    // Get the MacroInfo we want to reinstall.
+    MacroInfo *MacroToReInstall = iter->second.back();
+
+    if (MacroToReInstall)
+      // Reinstall the previously pushed macro.
+      appendDefMacroDirective(IdentInfo, MacroToReInstall, MessageLoc);
+
+    // Pop PragmaPushMacroInfo stack.
+    iter->second.pop_back();
+    if (iter->second.empty())
+      PragmaPushMacroInfo.erase(iter);
+  } else {
+    Diag(MessageLoc, diag::warn_pragma_pop_macro_no_push)
+      << IdentInfo->getName();
+  }
+}
+
+void Preprocessor::HandlePragmaIncludeAlias(Token &Tok) {
+  // We will either get a quoted filename or a bracketed filename, and we
+  // have to track which we got.  The first filename is the source name,
+  // and the second name is the mapped filename.  If the first is quoted,
+  // the second must be as well (cannot mix and match quotes and brackets).
+
+  // Get the open paren
+  Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << "(";
+    return;
+  }
+
+  // We expect either a quoted string literal, or a bracketed name
+  Token SourceFilenameTok;
+  if (LexHeaderName(SourceFilenameTok))
+    return;
+
+  StringRef SourceFileName;
+  SmallString<128> FileNameBuffer;
+  if (SourceFilenameTok.is(tok::header_name)) {
+    SourceFileName = getSpelling(SourceFilenameTok, FileNameBuffer);
+  } else {
+    Diag(Tok, diag::warn_pragma_include_alias_expected_filename);
+    return;
+  }
+  FileNameBuffer.clear();
+
+  // Now we expect a comma, followed by another include name
+  Lex(Tok);
+  if (Tok.isNot(tok::comma)) {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << ",";
+    return;
+  }
+
+  Token ReplaceFilenameTok;
+  if (LexHeaderName(ReplaceFilenameTok))
+    return;
+
+  StringRef ReplaceFileName;
+  if (ReplaceFilenameTok.is(tok::header_name)) {
+    ReplaceFileName = getSpelling(ReplaceFilenameTok, FileNameBuffer);
+  } else {
+    Diag(Tok, diag::warn_pragma_include_alias_expected_filename);
+    return;
+  }
+
+  // Finally, we expect the closing paren
+  Lex(Tok);
+  if (Tok.isNot(tok::r_paren)) {
+    Diag(Tok, diag::warn_pragma_include_alias_expected) << ")";
+    return;
+  }
+
+  // Now that we have the source and target filenames, we need to make sure
+  // they're both of the same type (angled vs non-angled)
+  StringRef OriginalSource = SourceFileName;
+
+  bool SourceIsAngled =
+    GetIncludeFilenameSpelling(SourceFilenameTok.getLocation(),
+                                SourceFileName);
+  bool ReplaceIsAngled =
+    GetIncludeFilenameSpelling(ReplaceFilenameTok.getLocation(),
+                                ReplaceFileName);
+  if (!SourceFileName.empty() && !ReplaceFileName.empty() &&
+      (SourceIsAngled != ReplaceIsAngled)) {
+    unsigned int DiagID;
+    if (SourceIsAngled)
+      DiagID = diag::warn_pragma_include_alias_mismatch_angle;
+    else
+      DiagID = diag::warn_pragma_include_alias_mismatch_quote;
+
+    Diag(SourceFilenameTok.getLocation(), DiagID)
+      << SourceFileName
+      << ReplaceFileName;
+
+    return;
+  }
+
+  // Now we can let the include handler know about this mapping
+  getHeaderSearchInfo().AddIncludeAlias(OriginalSource, ReplaceFileName);
+}
+
+// Lex a component of a module name: either an identifier or a string literal;
+// for components that can be expressed both ways, the two forms are equivalent.
+static bool LexModuleNameComponent(
+    Preprocessor &PP, Token &Tok,
+    std::pair<IdentifierInfo *, SourceLocation> &ModuleNameComponent,
+    bool First) {
+  PP.LexUnexpandedToken(Tok);
+  if (Tok.is(tok::string_literal) && !Tok.hasUDSuffix()) {
+    StringLiteralParser Literal(Tok, PP);
+    if (Literal.hadError)
+      return true;
+    ModuleNameComponent = std::make_pair(
+        PP.getIdentifierInfo(Literal.GetString()), Tok.getLocation());
+  } else if (!Tok.isAnnotation() && Tok.getIdentifierInfo()) {
+    ModuleNameComponent =
+        std::make_pair(Tok.getIdentifierInfo(), Tok.getLocation());
+  } else {
+    PP.Diag(Tok.getLocation(), diag::err_pp_expected_module_name) << First;
+    return true;
+  }
+  return false;
+}
+
+static bool LexModuleName(
+    Preprocessor &PP, Token &Tok,
+    llvm::SmallVectorImpl<std::pair<IdentifierInfo *, SourceLocation>>
+        &ModuleName) {
+  while (true) {
+    std::pair<IdentifierInfo*, SourceLocation> NameComponent;
+    if (LexModuleNameComponent(PP, Tok, NameComponent, ModuleName.empty()))
+      return true;
+    ModuleName.push_back(NameComponent);
+
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::period))
+      return false;
+  }
+}
+
+void Preprocessor::HandlePragmaModuleBuild(Token &Tok) {
+  SourceLocation Loc = Tok.getLocation();
+
+  std::pair<IdentifierInfo *, SourceLocation> ModuleNameLoc;
+  if (LexModuleNameComponent(*this, Tok, ModuleNameLoc, true))
+    return;
+  IdentifierInfo *ModuleName = ModuleNameLoc.first;
+
+  LexUnexpandedToken(Tok);
+  if (Tok.isNot(tok::eod)) {
+    Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+    DiscardUntilEndOfDirective();
+  }
+
+  CurLexer->LexingRawMode = true;
+
+  auto TryConsumeIdentifier = [&](StringRef Ident) -> bool {
+    if (Tok.getKind() != tok::raw_identifier ||
+        Tok.getRawIdentifier() != Ident)
+      return false;
+    CurLexer->Lex(Tok);
+    return true;
+  };
+
+  // Scan forward looking for the end of the module.
+  const char *Start = CurLexer->getBufferLocation();
+  const char *End = nullptr;
+  unsigned NestingLevel = 1;
+  while (true) {
+    End = CurLexer->getBufferLocation();
+    CurLexer->Lex(Tok);
+
+    if (Tok.is(tok::eof)) {
+      Diag(Loc, diag::err_pp_module_build_missing_end);
+      break;
+    }
+
+    if (Tok.isNot(tok::hash) || !Tok.isAtStartOfLine()) {
+      // Token was part of module; keep going.
+      continue;
+    }
+
+    // We hit something directive-shaped; check to see if this is the end
+    // of the module build.
+    CurLexer->ParsingPreprocessorDirective = true;
+    CurLexer->Lex(Tok);
+    if (TryConsumeIdentifier("pragma") && TryConsumeIdentifier("clang") &&
+        TryConsumeIdentifier("module")) {
+      if (TryConsumeIdentifier("build"))
+        // #pragma clang module build -> entering a nested module build.
+        ++NestingLevel;
+      else if (TryConsumeIdentifier("endbuild")) {
+        // #pragma clang module endbuild -> leaving a module build.
+        if (--NestingLevel == 0)
+          break;
+      }
+      // We should either be looking at the EOD or more of the current directive
+      // preceding the EOD. Either way we can ignore this token and keep going.
+      assert(Tok.getKind() != tok::eof && "missing EOD before EOF");
+    }
+  }
+
+  CurLexer->LexingRawMode = false;
+
+  // Load the extracted text as a preprocessed module.
+  assert(CurLexer->getBuffer().begin() <= Start &&
+         Start <= CurLexer->getBuffer().end() &&
+         CurLexer->getBuffer().begin() <= End &&
+         End <= CurLexer->getBuffer().end() &&
+         "module source range not contained within same file buffer");
+  TheModuleLoader.createModuleFromSource(Loc, ModuleName->getName(),
+                                         StringRef(Start, End - Start));
+}
+
+void Preprocessor::HandlePragmaHdrstop(Token &Tok) {
+  Lex(Tok);
+  if (Tok.is(tok::l_paren)) {
+    Diag(Tok.getLocation(), diag::warn_pp_hdrstop_filename_ignored);
+
+    std::string FileName;
+    if (!LexStringLiteral(Tok, FileName, "pragma hdrstop", false))
+      return;
+
+    if (Tok.isNot(tok::r_paren)) {
+      Diag(Tok, diag::err_expected) << tok::r_paren;
+      return;
+    }
+    Lex(Tok);
+  }
+  if (Tok.isNot(tok::eod))
+    Diag(Tok.getLocation(), diag::ext_pp_extra_tokens_at_eol)
+        << "pragma hdrstop";
+
+  if (creatingPCHWithPragmaHdrStop() &&
+      SourceMgr.isInMainFile(Tok.getLocation())) {
+    assert(CurLexer && "no lexer for #pragma hdrstop processing");
+    Token &Result = Tok;
+    Result.startToken();
+    CurLexer->FormTokenWithChars(Result, CurLexer->BufferEnd, tok::eof);
+    CurLexer->cutOffLexing();
+  }
+  if (usingPCHWithPragmaHdrStop())
+    SkippingUntilPragmaHdrStop = false;
+}
+
+/// AddPragmaHandler - Add the specified pragma handler to the preprocessor.
+/// If 'Namespace' is non-null, then it is a token required to exist on the
+/// pragma line before the pragma string starts, e.g. "STDC" or "GCC".
+void Preprocessor::AddPragmaHandler(StringRef Namespace,
+                                    PragmaHandler *Handler) {
+  PragmaNamespace *InsertNS = PragmaHandlers.get();
+
+  // If this is specified to be in a namespace, step down into it.
+  if (!Namespace.empty()) {
+    // If there is already a pragma handler with the name of this namespace,
+    // we either have an error (directive with the same name as a namespace) or
+    // we already have the namespace to insert into.
+    if (PragmaHandler *Existing = PragmaHandlers->FindHandler(Namespace)) {
+      InsertNS = Existing->getIfNamespace();
+      assert(InsertNS != nullptr && "Cannot have a pragma namespace and pragma"
+             " handler with the same name!");
+    } else {
+      // Otherwise, this namespace doesn't exist yet, create and insert the
+      // handler for it.
+      InsertNS = new PragmaNamespace(Namespace);
+      PragmaHandlers->AddPragma(InsertNS);
+    }
+  }
+
+  // Check to make sure we don't already have a pragma for this identifier.
+  assert(!InsertNS->FindHandler(Handler->getName()) &&
+         "Pragma handler already exists for this identifier!");
+  InsertNS->AddPragma(Handler);
+}
+
+/// RemovePragmaHandler - Remove the specific pragma handler from the
+/// preprocessor. If \arg Namespace is non-null, then it should be the
+/// namespace that \arg Handler was added to. It is an error to remove
+/// a handler that has not been registered.
+void Preprocessor::RemovePragmaHandler(StringRef Namespace,
+                                       PragmaHandler *Handler) {
+  PragmaNamespace *NS = PragmaHandlers.get();
+
+  // If this is specified to be in a namespace, step down into it.
+  if (!Namespace.empty()) {
+    PragmaHandler *Existing = PragmaHandlers->FindHandler(Namespace);
+    assert(Existing && "Namespace containing handler does not exist!");
+
+    NS = Existing->getIfNamespace();
+    assert(NS && "Invalid namespace, registered as a regular pragma handler!");
+  }
+
+  NS->RemovePragmaHandler(Handler);
+
+  // If this is a non-default namespace and it is now empty, remove it.
+  if (NS != PragmaHandlers.get() && NS->IsEmpty()) {
+    PragmaHandlers->RemovePragmaHandler(NS);
+    delete NS;
+  }
+}
+
+bool Preprocessor::LexOnOffSwitch(tok::OnOffSwitch &Result) {
+  Token Tok;
+  LexUnexpandedToken(Tok);
+
+  if (Tok.isNot(tok::identifier)) {
+    Diag(Tok, diag::ext_on_off_switch_syntax);
+    return true;
+  }
+  IdentifierInfo *II = Tok.getIdentifierInfo();
+  if (II->isStr("ON"))
+    Result = tok::OOS_ON;
+  else if (II->isStr("OFF"))
+    Result = tok::OOS_OFF;
+  else if (II->isStr("DEFAULT"))
+    Result = tok::OOS_DEFAULT;
+  else {
+    Diag(Tok, diag::ext_on_off_switch_syntax);
+    return true;
+  }
+
+  // Verify that this is followed by EOD.
+  LexUnexpandedToken(Tok);
+  if (Tok.isNot(tok::eod))
+    Diag(Tok, diag::ext_pragma_syntax_eod);
+  return false;
+}
+
+namespace {
+
+/// PragmaOnceHandler - "\#pragma once" marks the file as atomically included.
+struct PragmaOnceHandler : public PragmaHandler {
+  PragmaOnceHandler() : PragmaHandler("once") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &OnceTok) override {
+    PP.CheckEndOfDirective("pragma once");
+    PP.HandlePragmaOnce(OnceTok);
+  }
+};
+
+/// PragmaMarkHandler - "\#pragma mark ..." is ignored by the compiler, and the
+/// rest of the line is not lexed.
+struct PragmaMarkHandler : public PragmaHandler {
+  PragmaMarkHandler() : PragmaHandler("mark") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &MarkTok) override {
+    PP.HandlePragmaMark(MarkTok);
+  }
+};
+
+/// PragmaPoisonHandler - "\#pragma poison x" marks x as not usable.
+struct PragmaPoisonHandler : public PragmaHandler {
+  PragmaPoisonHandler() : PragmaHandler("poison") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &PoisonTok) override {
+    PP.HandlePragmaPoison();
+  }
+};
+
+/// PragmaSystemHeaderHandler - "\#pragma system_header" marks the current file
+/// as a system header, which silences warnings in it.
+struct PragmaSystemHeaderHandler : public PragmaHandler {
+  PragmaSystemHeaderHandler() : PragmaHandler("system_header") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &SHToken) override {
+    PP.HandlePragmaSystemHeader(SHToken);
+    PP.CheckEndOfDirective("pragma");
+  }
+};
+
+/// PragmaIncludeInsteadHandler - "\#pragma clang include_instead(header)" marks
+/// the current file as non-includable if the including header is not a system
+/// header.
+struct PragmaIncludeInsteadHandler : public PragmaHandler {
+  PragmaIncludeInsteadHandler() : PragmaHandler("include_instead") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &IIToken) override {
+    PP.HandlePragmaIncludeInstead(IIToken);
+  }
+};
+
+struct PragmaDependencyHandler : public PragmaHandler {
+  PragmaDependencyHandler() : PragmaHandler("dependency") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &DepToken) override {
+    PP.HandlePragmaDependency(DepToken);
+  }
+};
+
+struct PragmaDebugHandler : public PragmaHandler {
+  PragmaDebugHandler() : PragmaHandler("__debug") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &DebugToken) override {
+    Token Tok;
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::identifier)) {
+      PP.Diag(Tok, diag::warn_pragma_diagnostic_invalid);
+      return;
+    }
+    IdentifierInfo *II = Tok.getIdentifierInfo();
+
+    if (II->isStr("assert")) {
+      if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
+        llvm_unreachable("This is an assertion!");
+    } else if (II->isStr("crash")) {
+      llvm::Timer T("crash", "pragma crash");
+      llvm::TimeRegion R(&T);
+      if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
+        LLVM_BUILTIN_TRAP;
+    } else if (II->isStr("parser_crash")) {
+      if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash) {
+        Token Crasher;
+        Crasher.startToken();
+        Crasher.setKind(tok::annot_pragma_parser_crash);
+        Crasher.setAnnotationRange(SourceRange(Tok.getLocation()));
+        PP.EnterToken(Crasher, /*IsReinject*/ false);
+      }
+    } else if (II->isStr("dump")) {
+      Token Identifier;
+      PP.LexUnexpandedToken(Identifier);
+      if (auto *DumpII = Identifier.getIdentifierInfo()) {
+        Token DumpAnnot;
+        DumpAnnot.startToken();
+        DumpAnnot.setKind(tok::annot_pragma_dump);
+        DumpAnnot.setAnnotationRange(
+            SourceRange(Tok.getLocation(), Identifier.getLocation()));
+        DumpAnnot.setAnnotationValue(DumpII);
+        PP.DiscardUntilEndOfDirective();
+        PP.EnterToken(DumpAnnot, /*IsReinject*/false);
+      } else {
+        PP.Diag(Identifier, diag::warn_pragma_debug_missing_argument)
+            << II->getName();
+      }
+    } else if (II->isStr("diag_mapping")) {
+      Token DiagName;
+      PP.LexUnexpandedToken(DiagName);
+      if (DiagName.is(tok::eod))
+        PP.getDiagnostics().dump();
+      else if (DiagName.is(tok::string_literal) && !DiagName.hasUDSuffix()) {
+        StringLiteralParser Literal(DiagName, PP);
+        if (Literal.hadError)
+          return;
+        PP.getDiagnostics().dump(Literal.GetString());
+      } else {
+        PP.Diag(DiagName, diag::warn_pragma_debug_missing_argument)
+            << II->getName();
+      }
+    } else if (II->isStr("llvm_fatal_error")) {
+      if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
+        llvm::report_fatal_error("#pragma clang __debug llvm_fatal_error");
+    } else if (II->isStr("llvm_unreachable")) {
+      if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
+        llvm_unreachable("#pragma clang __debug llvm_unreachable");
+    } else if (II->isStr("macro")) {
+      Token MacroName;
+      PP.LexUnexpandedToken(MacroName);
+      auto *MacroII = MacroName.getIdentifierInfo();
+      if (MacroII)
+        PP.dumpMacroInfo(MacroII);
+      else
+        PP.Diag(MacroName, diag::warn_pragma_debug_missing_argument)
+            << II->getName();
+    } else if (II->isStr("module_map")) {
+      llvm::SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 8>
+          ModuleName;
+      if (LexModuleName(PP, Tok, ModuleName))
+        return;
+      ModuleMap &MM = PP.getHeaderSearchInfo().getModuleMap();
+      Module *M = nullptr;
+      for (auto IIAndLoc : ModuleName) {
+        M = MM.lookupModuleQualified(IIAndLoc.first->getName(), M);
+        if (!M) {
+          PP.Diag(IIAndLoc.second, diag::warn_pragma_debug_unknown_module)
+              << IIAndLoc.first;
+          return;
+        }
+      }
+      M->dump();
+    } else if (II->isStr("overflow_stack")) {
+      if (!PP.getPreprocessorOpts().DisablePragmaDebugCrash)
+        DebugOverflowStack();
+    } else if (II->isStr("captured")) {
+      HandleCaptured(PP);
+    } else if (II->isStr("modules")) {
+      struct ModuleVisitor {
+        Preprocessor &PP;
+        void visit(Module *M, bool VisibleOnly) {
+          SourceLocation ImportLoc = PP.getModuleImportLoc(M);
+          if (!VisibleOnly || ImportLoc.isValid()) {
+            llvm::errs() << M->getFullModuleName() << " ";
+            if (ImportLoc.isValid()) {
+              llvm::errs() << M << " visible ";
+              ImportLoc.print(llvm::errs(), PP.getSourceManager());
+            }
+            llvm::errs() << "\n";
+          }
+          for (Module *Sub : M->submodules()) {
+            if (!VisibleOnly || ImportLoc.isInvalid() || Sub->IsExplicit)
+              visit(Sub, VisibleOnly);
+          }
+        }
+        void visitAll(bool VisibleOnly) {
+          for (auto &NameAndMod :
+               PP.getHeaderSearchInfo().getModuleMap().modules())
+            visit(NameAndMod.second, VisibleOnly);
+        }
+      } Visitor{PP};
+
+      Token Kind;
+      PP.LexUnexpandedToken(Kind);
+      auto *DumpII = Kind.getIdentifierInfo();
+      if (!DumpII) {
+        PP.Diag(Kind, diag::warn_pragma_debug_missing_argument)
+            << II->getName();
+      } else if (DumpII->isStr("all")) {
+        Visitor.visitAll(false);
+      } else if (DumpII->isStr("visible")) {
+        Visitor.visitAll(true);
+      } else if (DumpII->isStr("building")) {
+        for (auto &Building : PP.getBuildingSubmodules()) {
+          llvm::errs() << "in " << Building.M->getFullModuleName();
+          if (Building.ImportLoc.isValid()) {
+            llvm::errs() << " imported ";
+            if (Building.IsPragma)
+              llvm::errs() << "via pragma ";
+            llvm::errs() << "at ";
+            Building.ImportLoc.print(llvm::errs(), PP.getSourceManager());
+            llvm::errs() << "\n";
+          }
+        }
+      } else {
+        PP.Diag(Tok, diag::warn_pragma_debug_unexpected_command)
+          << DumpII->getName();
+      }
+    } else {
+      PP.Diag(Tok, diag::warn_pragma_debug_unexpected_command)
+        << II->getName();
+    }
+
+    PPCallbacks *Callbacks = PP.getPPCallbacks();
+    if (Callbacks)
+      Callbacks->PragmaDebug(Tok.getLocation(), II->getName());
+  }
+
+  void HandleCaptured(Preprocessor &PP) {
+    Token Tok;
+    PP.LexUnexpandedToken(Tok);
+
+    if (Tok.isNot(tok::eod)) {
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol)
+        << "pragma clang __debug captured";
+      return;
+    }
+
+    SourceLocation NameLoc = Tok.getLocation();
+    MutableArrayRef<Token> Toks(
+        PP.getPreprocessorAllocator().Allocate<Token>(1), 1);
+    Toks[0].startToken();
+    Toks[0].setKind(tok::annot_pragma_captured);
+    Toks[0].setLocation(NameLoc);
+
+    PP.EnterTokenStream(Toks, /*DisableMacroExpansion=*/true,
+                        /*IsReinject=*/false);
+  }
+
+// Disable MSVC warning about runtime stack overflow.
+#ifdef _MSC_VER
+    #pragma warning(disable : 4717)
+#endif
+  static void DebugOverflowStack(void (*P)() = nullptr) {
+    void (*volatile Self)(void(*P)()) = DebugOverflowStack;
+    Self(reinterpret_cast<void(*)()>(Self));
+  }
+#ifdef _MSC_VER
+    #pragma warning(default : 4717)
+#endif
+};
+
+/// PragmaDiagnosticHandler - e.g. '\#pragma GCC diagnostic ignored "-Wformat"'
+struct PragmaDiagnosticHandler : public PragmaHandler {
+private:
+  const char *Namespace;
+
+public:
+  explicit PragmaDiagnosticHandler(const char *NS)
+      : PragmaHandler("diagnostic"), Namespace(NS) {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &DiagToken) override {
+    SourceLocation DiagLoc = DiagToken.getLocation();
+    Token Tok;
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::identifier)) {
+      PP.Diag(Tok, diag::warn_pragma_diagnostic_invalid);
+      return;
+    }
+    IdentifierInfo *II = Tok.getIdentifierInfo();
+    PPCallbacks *Callbacks = PP.getPPCallbacks();
+
+    if (II->isStr("pop")) {
+      if (!PP.getDiagnostics().popMappings(DiagLoc))
+        PP.Diag(Tok, diag::warn_pragma_diagnostic_cannot_pop);
+      else if (Callbacks)
+        Callbacks->PragmaDiagnosticPop(DiagLoc, Namespace);
+      return;
+    } else if (II->isStr("push")) {
+      PP.getDiagnostics().pushMappings(DiagLoc);
+      if (Callbacks)
+        Callbacks->PragmaDiagnosticPush(DiagLoc, Namespace);
+      return;
+    }
+
+    diag::Severity SV = llvm::StringSwitch<diag::Severity>(II->getName())
+                            .Case("ignored", diag::Severity::Ignored)
+                            .Case("warning", diag::Severity::Warning)
+                            .Case("error", diag::Severity::Error)
+                            .Case("fatal", diag::Severity::Fatal)
+                            .Default(diag::Severity());
+
+    if (SV == diag::Severity()) {
+      PP.Diag(Tok, diag::warn_pragma_diagnostic_invalid);
+      return;
+    }
+
+    PP.LexUnexpandedToken(Tok);
+    SourceLocation StringLoc = Tok.getLocation();
+
+    std::string WarningName;
+    if (!PP.FinishLexStringLiteral(Tok, WarningName, "pragma diagnostic",
+                                   /*AllowMacroExpansion=*/false))
+      return;
+
+    if (Tok.isNot(tok::eod)) {
+      PP.Diag(Tok.getLocation(), diag::warn_pragma_diagnostic_invalid_token);
+      return;
+    }
+
+    if (WarningName.size() < 3 || WarningName[0] != '-' ||
+        (WarningName[1] != 'W' && WarningName[1] != 'R')) {
+      PP.Diag(StringLoc, diag::warn_pragma_diagnostic_invalid_option);
+      return;
+    }
+
+    diag::Flavor Flavor = WarningName[1] == 'W' ? diag::Flavor::WarningOrError
+                                                : diag::Flavor::Remark;
+    StringRef Group = StringRef(WarningName).substr(2);
+    bool unknownDiag = false;
+    if (Group == "everything") {
+      // Special handling for pragma clang diagnostic ... "-Weverything".
+      // There is no formal group named "everything", so there has to be a
+      // special case for it.
+      PP.getDiagnostics().setSeverityForAll(Flavor, SV, DiagLoc);
+    } else
+      unknownDiag = PP.getDiagnostics().setSeverityForGroup(Flavor, Group, SV,
+                                                            DiagLoc);
+    if (unknownDiag)
+      PP.Diag(StringLoc, diag::warn_pragma_diagnostic_unknown_warning)
+        << WarningName;
+    else if (Callbacks)
+      Callbacks->PragmaDiagnostic(DiagLoc, Namespace, SV, WarningName);
+  }
+};
+
+/// "\#pragma hdrstop [<header-name-string>]"
+struct PragmaHdrstopHandler : public PragmaHandler {
+  PragmaHdrstopHandler() : PragmaHandler("hdrstop") {}
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &DepToken) override {
+    PP.HandlePragmaHdrstop(DepToken);
+  }
+};
+
+/// "\#pragma warning(...)".  MSVC's diagnostics do not map cleanly to clang's
+/// diagnostics, so we don't really implement this pragma.  We parse it and
+/// ignore it to avoid -Wunknown-pragma warnings.
+struct PragmaWarningHandler : public PragmaHandler {
+  PragmaWarningHandler() : PragmaHandler("warning") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    // Parse things like:
+    // warning(push, 1)
+    // warning(pop)
+    // warning(disable : 1 2 3 ; error : 4 5 6 ; suppress : 7 8 9)
+    SourceLocation DiagLoc = Tok.getLocation();
+    PPCallbacks *Callbacks = PP.getPPCallbacks();
+
+    PP.Lex(Tok);
+    if (Tok.isNot(tok::l_paren)) {
+      PP.Diag(Tok, diag::warn_pragma_warning_expected) << "(";
+      return;
+    }
+
+    PP.Lex(Tok);
+    IdentifierInfo *II = Tok.getIdentifierInfo();
+
+    if (II && II->isStr("push")) {
+      // #pragma warning( push[ ,n ] )
+      int Level = -1;
+      PP.Lex(Tok);
+      if (Tok.is(tok::comma)) {
+        PP.Lex(Tok);
+        uint64_t Value;
+        if (Tok.is(tok::numeric_constant) &&
+            PP.parseSimpleIntegerLiteral(Tok, Value))
+          Level = int(Value);
+        if (Level < 0 || Level > 4) {
+          PP.Diag(Tok, diag::warn_pragma_warning_push_level);
+          return;
+        }
+      }
+      PP.getDiagnostics().pushMappings(DiagLoc);
+      if (Callbacks)
+        Callbacks->PragmaWarningPush(DiagLoc, Level);
+    } else if (II && II->isStr("pop")) {
+      // #pragma warning( pop )
+      PP.Lex(Tok);
+      if (!PP.getDiagnostics().popMappings(DiagLoc))
+        PP.Diag(Tok, diag::warn_pragma_diagnostic_cannot_pop);
+      else if (Callbacks)
+        Callbacks->PragmaWarningPop(DiagLoc);
+    } else {
+      // #pragma warning( warning-specifier : warning-number-list
+      //                  [; warning-specifier : warning-number-list...] )
+      while (true) {
+        II = Tok.getIdentifierInfo();
+        if (!II && !Tok.is(tok::numeric_constant)) {
+          PP.Diag(Tok, diag::warn_pragma_warning_spec_invalid);
+          return;
+        }
+
+        // Figure out which warning specifier this is.
+        bool SpecifierValid;
+        PPCallbacks::PragmaWarningSpecifier Specifier;
+        if (II) {
+          int SpecifierInt = llvm::StringSwitch<int>(II->getName())
+                                 .Case("default", PPCallbacks::PWS_Default)
+                                 .Case("disable", PPCallbacks::PWS_Disable)
+                                 .Case("error", PPCallbacks::PWS_Error)
+                                 .Case("once", PPCallbacks::PWS_Once)
+                                 .Case("suppress", PPCallbacks::PWS_Suppress)
+                                 .Default(-1);
+          if ((SpecifierValid = SpecifierInt != -1))
+            Specifier =
+                static_cast<PPCallbacks::PragmaWarningSpecifier>(SpecifierInt);
+
+          // If we read a correct specifier, snatch next token (that should be
+          // ":", checked later).
+          if (SpecifierValid)
+            PP.Lex(Tok);
+        } else {
+          // Token is a numeric constant. It should be either 1, 2, 3 or 4.
+          uint64_t Value;
+          if (PP.parseSimpleIntegerLiteral(Tok, Value)) {
+            if ((SpecifierValid = (Value >= 1) && (Value <= 4)))
+              Specifier = static_cast<PPCallbacks::PragmaWarningSpecifier>(
+                  PPCallbacks::PWS_Level1 + Value - 1);
+          } else
+            SpecifierValid = false;
+          // Next token already snatched by parseSimpleIntegerLiteral.
+        }
+
+        if (!SpecifierValid) {
+          PP.Diag(Tok, diag::warn_pragma_warning_spec_invalid);
+          return;
+        }
+        if (Tok.isNot(tok::colon)) {
+          PP.Diag(Tok, diag::warn_pragma_warning_expected) << ":";
+          return;
+        }
+
+        // Collect the warning ids.
+        SmallVector<int, 4> Ids;
+        PP.Lex(Tok);
+        while (Tok.is(tok::numeric_constant)) {
+          uint64_t Value;
+          if (!PP.parseSimpleIntegerLiteral(Tok, Value) || Value == 0 ||
+              Value > INT_MAX) {
+            PP.Diag(Tok, diag::warn_pragma_warning_expected_number);
+            return;
+          }
+          Ids.push_back(int(Value));
+        }
+
+        // Only act on disable for now.
+        diag::Severity SV = diag::Severity();
+        if (Specifier == PPCallbacks::PWS_Disable)
+          SV = diag::Severity::Ignored;
+        if (SV != diag::Severity())
+          for (int Id : Ids) {
+            if (auto Group = diagGroupFromCLWarningID(Id)) {
+              bool unknownDiag = PP.getDiagnostics().setSeverityForGroup(
+                  diag::Flavor::WarningOrError, *Group, SV, DiagLoc);
+              assert(!unknownDiag &&
+                     "wd table should only contain known diags");
+              (void)unknownDiag;
+            }
+          }
+
+        if (Callbacks)
+          Callbacks->PragmaWarning(DiagLoc, Specifier, Ids);
+
+        // Parse the next specifier if there is a semicolon.
+        if (Tok.isNot(tok::semi))
+          break;
+        PP.Lex(Tok);
+      }
+    }
+
+    if (Tok.isNot(tok::r_paren)) {
+      PP.Diag(Tok, diag::warn_pragma_warning_expected) << ")";
+      return;
+    }
+
+    PP.Lex(Tok);
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma warning";
+  }
+};
+
+/// "\#pragma execution_character_set(...)". MSVC supports this pragma only
+/// for "UTF-8". We parse it and ignore it if UTF-8 is provided and warn
+/// otherwise to avoid -Wunknown-pragma warnings.
+struct PragmaExecCharsetHandler : public PragmaHandler {
+  PragmaExecCharsetHandler() : PragmaHandler("execution_character_set") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    // Parse things like:
+    // execution_character_set(push, "UTF-8")
+    // execution_character_set(pop)
+    SourceLocation DiagLoc = Tok.getLocation();
+    PPCallbacks *Callbacks = PP.getPPCallbacks();
+
+    PP.Lex(Tok);
+    if (Tok.isNot(tok::l_paren)) {
+      PP.Diag(Tok, diag::warn_pragma_exec_charset_expected) << "(";
+      return;
+    }
+
+    PP.Lex(Tok);
+    IdentifierInfo *II = Tok.getIdentifierInfo();
+
+    if (II && II->isStr("push")) {
+      // #pragma execution_character_set( push[ , string ] )
+      PP.Lex(Tok);
+      if (Tok.is(tok::comma)) {
+        PP.Lex(Tok);
+
+        std::string ExecCharset;
+        if (!PP.FinishLexStringLiteral(Tok, ExecCharset,
+                                       "pragma execution_character_set",
+                                       /*AllowMacroExpansion=*/false))
+          return;
+
+        // MSVC supports either of these, but nothing else.
+        if (ExecCharset != "UTF-8" && ExecCharset != "utf-8") {
+          PP.Diag(Tok, diag::warn_pragma_exec_charset_push_invalid) << ExecCharset;
+          return;
+        }
+      }
+      if (Callbacks)
+        Callbacks->PragmaExecCharsetPush(DiagLoc, "UTF-8");
+    } else if (II && II->isStr("pop")) {
+      // #pragma execution_character_set( pop )
+      PP.Lex(Tok);
+      if (Callbacks)
+        Callbacks->PragmaExecCharsetPop(DiagLoc);
+    } else {
+      PP.Diag(Tok, diag::warn_pragma_exec_charset_spec_invalid);
+      return;
+    }
+
+    if (Tok.isNot(tok::r_paren)) {
+      PP.Diag(Tok, diag::warn_pragma_exec_charset_expected) << ")";
+      return;
+    }
+
+    PP.Lex(Tok);
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma execution_character_set";
+  }
+};
+
+/// PragmaIncludeAliasHandler - "\#pragma include_alias("...")".
+struct PragmaIncludeAliasHandler : public PragmaHandler {
+  PragmaIncludeAliasHandler() : PragmaHandler("include_alias") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &IncludeAliasTok) override {
+    PP.HandlePragmaIncludeAlias(IncludeAliasTok);
+  }
+};
+
+/// PragmaMessageHandler - Handle the microsoft and gcc \#pragma message
+/// extension.  The syntax is:
+/// \code
+///   #pragma message(string)
+/// \endcode
+/// OR, in GCC mode:
+/// \code
+///   #pragma message string
+/// \endcode
+/// string is a string, which is fully macro expanded, and permits string
+/// concatenation, embedded escape characters, etc... See MSDN for more details.
+/// Also handles \#pragma GCC warning and \#pragma GCC error which take the same
+/// form as \#pragma message.
+struct PragmaMessageHandler : public PragmaHandler {
+private:
+  const PPCallbacks::PragmaMessageKind Kind;
+  const StringRef Namespace;
+
+  static const char* PragmaKind(PPCallbacks::PragmaMessageKind Kind,
+                                bool PragmaNameOnly = false) {
+    switch (Kind) {
+      case PPCallbacks::PMK_Message:
+        return PragmaNameOnly ? "message" : "pragma message";
+      case PPCallbacks::PMK_Warning:
+        return PragmaNameOnly ? "warning" : "pragma warning";
+      case PPCallbacks::PMK_Error:
+        return PragmaNameOnly ? "error" : "pragma error";
+    }
+    llvm_unreachable("Unknown PragmaMessageKind!");
+  }
+
+public:
+  PragmaMessageHandler(PPCallbacks::PragmaMessageKind Kind,
+                       StringRef Namespace = StringRef())
+      : PragmaHandler(PragmaKind(Kind, true)), Kind(Kind),
+        Namespace(Namespace) {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    SourceLocation MessageLoc = Tok.getLocation();
+    PP.Lex(Tok);
+    bool ExpectClosingParen = false;
+    switch (Tok.getKind()) {
+    case tok::l_paren:
+      // We have a MSVC style pragma message.
+      ExpectClosingParen = true;
+      // Read the string.
+      PP.Lex(Tok);
+      break;
+    case tok::string_literal:
+      // We have a GCC style pragma message, and we just read the string.
+      break;
+    default:
+      PP.Diag(MessageLoc, diag::err_pragma_message_malformed) << Kind;
+      return;
+    }
+
+    std::string MessageString;
+    if (!PP.FinishLexStringLiteral(Tok, MessageString, PragmaKind(Kind),
+                                   /*AllowMacroExpansion=*/true))
+      return;
+
+    if (ExpectClosingParen) {
+      if (Tok.isNot(tok::r_paren)) {
+        PP.Diag(Tok.getLocation(), diag::err_pragma_message_malformed) << Kind;
+        return;
+      }
+      PP.Lex(Tok);  // eat the r_paren.
+    }
+
+    if (Tok.isNot(tok::eod)) {
+      PP.Diag(Tok.getLocation(), diag::err_pragma_message_malformed) << Kind;
+      return;
+    }
+
+    // Output the message.
+    PP.Diag(MessageLoc, (Kind == PPCallbacks::PMK_Error)
+                          ? diag::err_pragma_message
+                          : diag::warn_pragma_message) << MessageString;
+
+    // If the pragma is lexically sound, notify any interested PPCallbacks.
+    if (PPCallbacks *Callbacks = PP.getPPCallbacks())
+      Callbacks->PragmaMessage(MessageLoc, Namespace, Kind, MessageString);
+  }
+};
+
+/// Handle the clang \#pragma module import extension. The syntax is:
+/// \code
+///   #pragma clang module import some.module.name
+/// \endcode
+struct PragmaModuleImportHandler : public PragmaHandler {
+  PragmaModuleImportHandler() : PragmaHandler("import") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    SourceLocation ImportLoc = Tok.getLocation();
+
+    // Read the module name.
+    llvm::SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 8>
+        ModuleName;
+    if (LexModuleName(PP, Tok, ModuleName))
+      return;
+
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    // If we have a non-empty module path, load the named module.
+    Module *Imported =
+        PP.getModuleLoader().loadModule(ImportLoc, ModuleName, Module::Hidden,
+                                      /*IsInclusionDirective=*/false);
+    if (!Imported)
+      return;
+
+    PP.makeModuleVisible(Imported, ImportLoc);
+    PP.EnterAnnotationToken(SourceRange(ImportLoc, ModuleName.back().second),
+                            tok::annot_module_include, Imported);
+    if (auto *CB = PP.getPPCallbacks())
+      CB->moduleImport(ImportLoc, ModuleName, Imported);
+  }
+};
+
+/// Handle the clang \#pragma module begin extension. The syntax is:
+/// \code
+///   #pragma clang module begin some.module.name
+///   ...
+///   #pragma clang module end
+/// \endcode
+struct PragmaModuleBeginHandler : public PragmaHandler {
+  PragmaModuleBeginHandler() : PragmaHandler("begin") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    SourceLocation BeginLoc = Tok.getLocation();
+
+    // Read the module name.
+    llvm::SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 8>
+        ModuleName;
+    if (LexModuleName(PP, Tok, ModuleName))
+      return;
+
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    // We can only enter submodules of the current module.
+    StringRef Current = PP.getLangOpts().CurrentModule;
+    if (ModuleName.front().first->getName() != Current) {
+      PP.Diag(ModuleName.front().second, diag::err_pp_module_begin_wrong_module)
+        << ModuleName.front().first << (ModuleName.size() > 1)
+        << Current.empty() << Current;
+      return;
+    }
+
+    // Find the module we're entering. We require that a module map for it
+    // be loaded or implicitly loadable.
+    auto &HSI = PP.getHeaderSearchInfo();
+    Module *M = HSI.lookupModule(Current, ModuleName.front().second);
+    if (!M) {
+      PP.Diag(ModuleName.front().second,
+              diag::err_pp_module_begin_no_module_map) << Current;
+      return;
+    }
+    for (unsigned I = 1; I != ModuleName.size(); ++I) {
+      auto *NewM = M->findOrInferSubmodule(ModuleName[I].first->getName());
+      if (!NewM) {
+        PP.Diag(ModuleName[I].second, diag::err_pp_module_begin_no_submodule)
+          << M->getFullModuleName() << ModuleName[I].first;
+        return;
+      }
+      M = NewM;
+    }
+
+    // If the module isn't available, it doesn't make sense to enter it.
+    if (Preprocessor::checkModuleIsAvailable(
+            PP.getLangOpts(), PP.getTargetInfo(), PP.getDiagnostics(), M)) {
+      PP.Diag(BeginLoc, diag::note_pp_module_begin_here)
+        << M->getTopLevelModuleName();
+      return;
+    }
+
+    // Enter the scope of the submodule.
+    PP.EnterSubmodule(M, BeginLoc, /*ForPragma*/true);
+    PP.EnterAnnotationToken(SourceRange(BeginLoc, ModuleName.back().second),
+                            tok::annot_module_begin, M);
+  }
+};
+
+/// Handle the clang \#pragma module end extension.
+struct PragmaModuleEndHandler : public PragmaHandler {
+  PragmaModuleEndHandler() : PragmaHandler("end") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    SourceLocation Loc = Tok.getLocation();
+
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    Module *M = PP.LeaveSubmodule(/*ForPragma*/true);
+    if (M)
+      PP.EnterAnnotationToken(SourceRange(Loc), tok::annot_module_end, M);
+    else
+      PP.Diag(Loc, diag::err_pp_module_end_without_module_begin);
+  }
+};
+
+/// Handle the clang \#pragma module build extension.
+struct PragmaModuleBuildHandler : public PragmaHandler {
+  PragmaModuleBuildHandler() : PragmaHandler("build") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    PP.HandlePragmaModuleBuild(Tok);
+  }
+};
+
+/// Handle the clang \#pragma module load extension.
+struct PragmaModuleLoadHandler : public PragmaHandler {
+  PragmaModuleLoadHandler() : PragmaHandler("load") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    SourceLocation Loc = Tok.getLocation();
+
+    // Read the module name.
+    llvm::SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 8>
+        ModuleName;
+    if (LexModuleName(PP, Tok, ModuleName))
+      return;
+
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    // Load the module, don't make it visible.
+    PP.getModuleLoader().loadModule(Loc, ModuleName, Module::Hidden,
+                                    /*IsInclusionDirective=*/false);
+  }
+};
+
+/// PragmaPushMacroHandler - "\#pragma push_macro" saves the value of the
+/// macro on the top of the stack.
+struct PragmaPushMacroHandler : public PragmaHandler {
+  PragmaPushMacroHandler() : PragmaHandler("push_macro") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &PushMacroTok) override {
+    PP.HandlePragmaPushMacro(PushMacroTok);
+  }
+};
+
+/// PragmaPopMacroHandler - "\#pragma pop_macro" sets the value of the
+/// macro to the value on the top of the stack.
+struct PragmaPopMacroHandler : public PragmaHandler {
+  PragmaPopMacroHandler() : PragmaHandler("pop_macro") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &PopMacroTok) override {
+    PP.HandlePragmaPopMacro(PopMacroTok);
+  }
+};
+
+/// PragmaARCCFCodeAuditedHandler -
+///   \#pragma clang arc_cf_code_audited begin/end
+struct PragmaARCCFCodeAuditedHandler : public PragmaHandler {
+  PragmaARCCFCodeAuditedHandler() : PragmaHandler("arc_cf_code_audited") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &NameTok) override {
+    SourceLocation Loc = NameTok.getLocation();
+    bool IsBegin;
+
+    Token Tok;
+
+    // Lex the 'begin' or 'end'.
+    PP.LexUnexpandedToken(Tok);
+    const IdentifierInfo *BeginEnd = Tok.getIdentifierInfo();
+    if (BeginEnd && BeginEnd->isStr("begin")) {
+      IsBegin = true;
+    } else if (BeginEnd && BeginEnd->isStr("end")) {
+      IsBegin = false;
+    } else {
+      PP.Diag(Tok.getLocation(), diag::err_pp_arc_cf_code_audited_syntax);
+      return;
+    }
+
+    // Verify that this is followed by EOD.
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    // The start location of the active audit.
+    SourceLocation BeginLoc = PP.getPragmaARCCFCodeAuditedInfo().second;
+
+    // The start location we want after processing this.
+    SourceLocation NewLoc;
+
+    if (IsBegin) {
+      // Complain about attempts to re-enter an audit.
+      if (BeginLoc.isValid()) {
+        PP.Diag(Loc, diag::err_pp_double_begin_of_arc_cf_code_audited);
+        PP.Diag(BeginLoc, diag::note_pragma_entered_here);
+      }
+      NewLoc = Loc;
+    } else {
+      // Complain about attempts to leave an audit that doesn't exist.
+      if (!BeginLoc.isValid()) {
+        PP.Diag(Loc, diag::err_pp_unmatched_end_of_arc_cf_code_audited);
+        return;
+      }
+      NewLoc = SourceLocation();
+    }
+
+    PP.setPragmaARCCFCodeAuditedInfo(NameTok.getIdentifierInfo(), NewLoc);
+  }
+};
+
+/// PragmaAssumeNonNullHandler -
+///   \#pragma clang assume_nonnull begin/end
+struct PragmaAssumeNonNullHandler : public PragmaHandler {
+  PragmaAssumeNonNullHandler() : PragmaHandler("assume_nonnull") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &NameTok) override {
+    SourceLocation Loc = NameTok.getLocation();
+    bool IsBegin;
+
+    Token Tok;
+
+    // Lex the 'begin' or 'end'.
+    PP.LexUnexpandedToken(Tok);
+    const IdentifierInfo *BeginEnd = Tok.getIdentifierInfo();
+    if (BeginEnd && BeginEnd->isStr("begin")) {
+      IsBegin = true;
+    } else if (BeginEnd && BeginEnd->isStr("end")) {
+      IsBegin = false;
+    } else {
+      PP.Diag(Tok.getLocation(), diag::err_pp_assume_nonnull_syntax);
+      return;
+    }
+
+    // Verify that this is followed by EOD.
+    PP.LexUnexpandedToken(Tok);
+    if (Tok.isNot(tok::eod))
+      PP.Diag(Tok, diag::ext_pp_extra_tokens_at_eol) << "pragma";
+
+    // The start location of the active audit.
+    SourceLocation BeginLoc = PP.getPragmaAssumeNonNullLoc();
+
+    // The start location we want after processing this.
+    SourceLocation NewLoc;
+    PPCallbacks *Callbacks = PP.getPPCallbacks();
+
+    if (IsBegin) {
+      // Complain about attempts to re-enter an audit.
+      if (BeginLoc.isValid()) {
+        PP.Diag(Loc, diag::err_pp_double_begin_of_assume_nonnull);
+        PP.Diag(BeginLoc, diag::note_pragma_entered_here);
+      }
+      NewLoc = Loc;
+      if (Callbacks)
+        Callbacks->PragmaAssumeNonNullBegin(NewLoc);
+    } else {
+      // Complain about attempts to leave an audit that doesn't exist.
+      if (!BeginLoc.isValid()) {
+        PP.Diag(Loc, diag::err_pp_unmatched_end_of_assume_nonnull);
+        return;
+      }
+      NewLoc = SourceLocation();
+      if (Callbacks)
+        Callbacks->PragmaAssumeNonNullEnd(NewLoc);
+    }
+
+    PP.setPragmaAssumeNonNullLoc(NewLoc);
+  }
+};
+
+/// Handle "\#pragma region [...]"
+///
+/// The syntax is
+/// \code
+///   #pragma region [optional name]
+///   #pragma endregion [optional comment]
+/// \endcode
+///
+/// \note This is
+/// <a href="http://msdn.microsoft.com/en-us/library/b6xkz944(v=vs.80).aspx">editor-only</a>
+/// pragma, just skipped by compiler.
+struct PragmaRegionHandler : public PragmaHandler {
+  PragmaRegionHandler(const char *pragma) : PragmaHandler(pragma) {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &NameTok) override {
+    // #pragma region: endregion matches can be verified
+    // __pragma(region): no sense, but ignored by msvc
+    // _Pragma is not valid for MSVC, but there isn't any point
+    // to handle a _Pragma differently.
+  }
+};
+
+/// This handles parsing pragmas that take a macro name and optional message
+static IdentifierInfo *HandleMacroAnnotationPragma(Preprocessor &PP, Token &Tok,
+                                                   const char *Pragma,
+                                                   std::string &MessageString) {
+  std::string Macro;
+
+  PP.Lex(Tok);
+  if (Tok.isNot(tok::l_paren)) {
+    PP.Diag(Tok, diag::err_expected) << "(";
+    return nullptr;
+  }
+
+  PP.LexUnexpandedToken(Tok);
+  if (!Tok.is(tok::identifier)) {
+    PP.Diag(Tok, diag::err_expected) << tok::identifier;
+    return nullptr;
+  }
+  IdentifierInfo *II = Tok.getIdentifierInfo();
+
+  if (!II->hasMacroDefinition()) {
+    PP.Diag(Tok, diag::err_pp_visibility_non_macro) << II;
+    return nullptr;
+  }
+
+  PP.Lex(Tok);
+  if (Tok.is(tok::comma)) {
+    PP.Lex(Tok);
+    if (!PP.FinishLexStringLiteral(Tok, MessageString, Pragma,
+                                   /*AllowMacroExpansion=*/true))
+      return nullptr;
+  }
+
+  if (Tok.isNot(tok::r_paren)) {
+    PP.Diag(Tok, diag::err_expected) << ")";
+    return nullptr;
+  }
+  return II;
+}
+
+/// "\#pragma clang deprecated(...)"
+///
+/// The syntax is
+/// \code
+///   #pragma clang deprecate(MACRO_NAME [, Message])
+/// \endcode
+struct PragmaDeprecatedHandler : public PragmaHandler {
+  PragmaDeprecatedHandler() : PragmaHandler("deprecated") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    std::string MessageString;
+
+    if (IdentifierInfo *II = HandleMacroAnnotationPragma(
+            PP, Tok, "#pragma clang deprecated", MessageString)) {
+      II->setIsDeprecatedMacro(true);
+      PP.addMacroDeprecationMsg(II, std::move(MessageString),
+                                Tok.getLocation());
+    }
+  }
+};
+
+/// "\#pragma clang restrict_expansion(...)"
+///
+/// The syntax is
+/// \code
+///   #pragma clang restrict_expansion(MACRO_NAME [, Message])
+/// \endcode
+struct PragmaRestrictExpansionHandler : public PragmaHandler {
+  PragmaRestrictExpansionHandler() : PragmaHandler("restrict_expansion") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    std::string MessageString;
+
+    if (IdentifierInfo *II = HandleMacroAnnotationPragma(
+            PP, Tok, "#pragma clang restrict_expansion", MessageString)) {
+      II->setIsRestrictExpansion(true);
+      PP.addRestrictExpansionMsg(II, std::move(MessageString),
+                                 Tok.getLocation());
+    }
+  }
+};
+
+/// "\#pragma clang final(...)"
+///
+/// The syntax is
+/// \code
+///   #pragma clang final(MACRO_NAME)
+/// \endcode
+struct PragmaFinalHandler : public PragmaHandler {
+  PragmaFinalHandler() : PragmaHandler("final") {}
+
+  void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+                    Token &Tok) override {
+    std::string Macro;
+
+    PP.Lex(Tok);
+    if (Tok.isNot(tok::l_paren)) {
+      PP.Diag(Tok, diag::err_expected) << "(";
+      return;
+    }
+
+    PP.LexUnexpandedToken(Tok);
+    if (!Tok.is(tok::identifier)) {
+      PP.Diag(Tok, diag::err_expected) << tok::identifier;
+      return;
+    }
+    IdentifierInfo *II = Tok.getIdentifierInfo();
+
+    if (!II->hasMacroDefinition()) {
+      PP.Diag(Tok, diag::err_pp_visibility_non_macro) << II;
+      return;
+    }
+
+    PP.Lex(Tok);
+    if (Tok.isNot(tok::r_paren)) {
+      PP.Diag(Tok, diag::err_expected) << ")";
+      return;
+    }
+    II->setIsFinal(true);
+    PP.addFinalLoc(II, Tok.getLocation());
+  }
+};
+
+} // namespace
+
+/// RegisterBuiltinPragmas - Install the standard preprocessor pragmas:
+/// \#pragma GCC poison/system_header/dependency and \#pragma once.
+void Preprocessor::RegisterBuiltinPragmas() {
+  AddPragmaHandler(new PragmaOnceHandler());
+  AddPragmaHandler(new PragmaMarkHandler());
+  AddPragmaHandler(new PragmaPushMacroHandler());
+  AddPragmaHandler(new PragmaPopMacroHandler());
+  AddPragmaHandler(new PragmaMessageHandler(PPCallbacks::PMK_Message));
+
+  // #pragma GCC ...
+  AddPragmaHandler("GCC", new PragmaPoisonHandler());
+  AddPragmaHandler("GCC", new PragmaSystemHeaderHandler());
+  AddPragmaHandler("GCC", new PragmaDependencyHandler());
+  AddPragmaHandler("GCC", new PragmaDiagnosticHandler("GCC"));
+  AddPragmaHandler("GCC", new PragmaMessageHandler(PPCallbacks::PMK_Warning,
+                                                   "GCC"));
+  AddPragmaHandler("GCC", new PragmaMessageHandler(PPCallbacks::PMK_Error,
+                                                   "GCC"));
+  // #pragma clang ...
+  AddPragmaHandler("clang", new PragmaPoisonHandler());
+  AddPragmaHandler("clang", new PragmaSystemHeaderHandler());
+  AddPragmaHandler("clang", new PragmaIncludeInsteadHandler());
+  AddPragmaHandler("clang", new PragmaDebugHandler());
+  AddPragmaHandler("clang", new PragmaDependencyHandler());
+  AddPragmaHandler("clang", new PragmaDiagnosticHandler("clang"));
+  AddPragmaHandler("clang", new PragmaARCCFCodeAuditedHandler());
+  AddPragmaHandler("clang", new PragmaAssumeNonNullHandler());
+  AddPragmaHandler("clang", new PragmaDeprecatedHandler());
+  AddPragmaHandler("clang", new PragmaRestrictExpansionHandler());
+  AddPragmaHandler("clang", new PragmaFinalHandler());
+
+  // #pragma clang module ...
+  auto *ModuleHandler = new PragmaNamespace("module");
+  AddPragmaHandler("clang", ModuleHandler);
+  ModuleHandler->AddPragma(new PragmaModuleImportHandler());
+  ModuleHandler->AddPragma(new PragmaModuleBeginHandler());
+  ModuleHandler->AddPragma(new PragmaModuleEndHandler());
+  ModuleHandler->AddPragma(new PragmaModuleBuildHandler());
+  ModuleHandler->AddPragma(new PragmaModuleLoadHandler());
+
+  // Add region pragmas.
+  AddPragmaHandler(new PragmaRegionHandler("region"));
+  AddPragmaHandler(new PragmaRegionHandler("endregion"));
+
+  // MS extensions.
+  if (LangOpts.MicrosoftExt) {
+    AddPragmaHandler(new PragmaWarningHandler());
+    AddPragmaHandler(new PragmaExecCharsetHandler());
+    AddPragmaHandler(new PragmaIncludeAliasHandler());
+    AddPragmaHandler(new PragmaHdrstopHandler());
+    AddPragmaHandler(new PragmaSystemHeaderHandler());
+  }
+
+  // Pragmas added by plugins
+  for (const PragmaHandlerRegistry::entry &handler :
+       PragmaHandlerRegistry::entries()) {
+    AddPragmaHandler(handler.instantiate().release());
+  }
+}
+
+/// Ignore all pragmas, useful for modes such as -Eonly which would otherwise
+/// warn about those pragmas being unknown.
+void Preprocessor::IgnorePragmas() {
+  AddPragmaHandler(new EmptyPragmaHandler());
+  // Also ignore all pragmas in all namespaces created
+  // in Preprocessor::RegisterBuiltinPragmas().
+  AddPragmaHandler("GCC", new EmptyPragmaHandler());
+  AddPragmaHandler("clang", new EmptyPragmaHandler());
+}