//===- SourceManager.h - Track and cache source files -----------*- C++ -*-===//
 
//
 
// 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
 
//
 
//===----------------------------------------------------------------------===//
 
//
 
/// \file
 
/// Defines the SourceManager interface.
 
///
 
/// There are three different types of locations in a %file: a spelling
 
/// location, an expansion location, and a presumed location.
 
///
 
/// Given an example of:
 
/// \code
 
/// #define min(x, y) x < y ? x : y
 
/// \endcode
 
///
 
/// and then later on a use of min:
 
/// \code
 
/// #line 17
 
/// return min(a, b);
 
/// \endcode
 
///
 
/// The expansion location is the line in the source code where the macro
 
/// was expanded (the return statement), the spelling location is the
 
/// location in the source where the macro was originally defined,
 
/// and the presumed location is where the line directive states that
 
/// the line is 17, or any other line.
 
//
 
//===----------------------------------------------------------------------===//
 
 
 
#ifndef LLVM_CLANG_BASIC_SOURCEMANAGER_H
 
#define LLVM_CLANG_BASIC_SOURCEMANAGER_H
 
 
 
#include "clang/Basic/Diagnostic.h"
 
#include "clang/Basic/FileEntry.h"
 
#include "clang/Basic/FileManager.h"
 
#include "clang/Basic/SourceLocation.h"
 
#include "llvm/ADT/ArrayRef.h"
 
#include "llvm/ADT/BitVector.h"
 
#include "llvm/ADT/DenseMap.h"
 
#include "llvm/ADT/DenseSet.h"
 
#include "llvm/ADT/IntrusiveRefCntPtr.h"
 
#include "llvm/ADT/PointerIntPair.h"
 
#include "llvm/ADT/SmallVector.h"
 
#include "llvm/ADT/StringRef.h"
 
#include "llvm/Support/Allocator.h"
 
#include "llvm/Support/Compiler.h"
 
#include "llvm/Support/MemoryBuffer.h"
 
#include <cassert>
 
#include <cstddef>
 
#include <map>
 
#include <memory>
 
#include <optional>
 
#include <string>
 
#include <utility>
 
#include <vector>
 
 
 
namespace clang {
 
 
 
class ASTReader;
 
class ASTWriter;
 
class FileManager;
 
class LineTableInfo;
 
class SourceManager;
 
 
 
/// Public enums and private classes that are part of the
 
/// SourceManager implementation.
 
namespace SrcMgr {
 
 
 
/// Indicates whether a file or directory holds normal user code,
 
/// system code, or system code which is implicitly 'extern "C"' in C++ mode.
 
///
 
/// Entire directories can be tagged with this (this is maintained by
 
/// DirectoryLookup and friends) as can specific FileInfos when a \#pragma
 
/// system_header is seen or in various other cases.
 
///
 
enum CharacteristicKind {
 
  C_User,
 
  C_System,
 
  C_ExternCSystem,
 
  C_User_ModuleMap,
 
  C_System_ModuleMap
 
};
 
 
 
/// Determine whether a file / directory characteristic is for system code.
 
inline bool isSystem(CharacteristicKind CK) {
 
  return CK != C_User && CK != C_User_ModuleMap;
 
}
 
 
 
/// Determine whether a file characteristic is for a module map.
 
inline bool isModuleMap(CharacteristicKind CK) {
 
  return CK == C_User_ModuleMap || CK == C_System_ModuleMap;
 
}
 
 
 
/// Mapping of line offsets into a source file. This does not own the storage
 
/// for the line numbers.
 
class LineOffsetMapping {
 
public:
 
  explicit operator bool() const { return Storage; }
 
  unsigned size() const {
 
    assert(Storage);
 
    return Storage[0];
 
  }
 
  ArrayRef<unsigned> getLines() const {
 
    assert(Storage);
 
    return ArrayRef<unsigned>(Storage + 1, Storage + 1 + size());
 
  }
 
  const unsigned *begin() const { return getLines().begin(); }
 
  const unsigned *end() const { return getLines().end(); }
 
  const unsigned &operator[](int I) const { return getLines()[I]; }
 
 
 
  static LineOffsetMapping get(llvm::MemoryBufferRef Buffer,
 
                               llvm::BumpPtrAllocator &Alloc);
 
 
 
  LineOffsetMapping() = default;
 
  LineOffsetMapping(ArrayRef<unsigned> LineOffsets,
 
                    llvm::BumpPtrAllocator &Alloc);
 
 
 
private:
 
  /// First element is the size, followed by elements at off-by-one indexes.
 
  unsigned *Storage = nullptr;
 
};
 
 
 
/// One instance of this struct is kept for every file loaded or used.
 
///
 
/// This object owns the MemoryBuffer object.
 
class alignas(8) ContentCache {
 
  /// The actual buffer containing the characters from the input
 
  /// file.
 
  mutable std::unique_ptr<llvm::MemoryBuffer> Buffer;
 
 
 
public:
 
  /// Reference to the file entry representing this ContentCache.
 
  ///
 
  /// This reference does not own the FileEntry object.
 
  ///
 
  /// It is possible for this to be NULL if the ContentCache encapsulates
 
  /// an imaginary text buffer.
 
  ///
 
  /// FIXME: Make non-optional using a virtual file as needed, remove \c
 
  /// Filename and use \c OrigEntry.getNameAsRequested() instead.
 
  OptionalFileEntryRefDegradesToFileEntryPtr OrigEntry;
 
 
 
  /// References the file which the contents were actually loaded from.
 
  ///
 
  /// Can be different from 'Entry' if we overridden the contents of one file
 
  /// with the contents of another file.
 
  const FileEntry *ContentsEntry;
 
 
 
  /// The filename that is used to access OrigEntry.
 
  ///
 
  /// FIXME: Remove this once OrigEntry is a FileEntryRef with a stable name.
 
  StringRef Filename;
 
 
 
  /// A bump pointer allocated array of offsets for each source line.
 
  ///
 
  /// This is lazily computed.  The lines are owned by the SourceManager
 
  /// BumpPointerAllocator object.
 
  mutable LineOffsetMapping SourceLineCache;
 
 
 
  /// Indicates whether the buffer itself was provided to override
 
  /// the actual file contents.
 
  ///
 
  /// When true, the original entry may be a virtual file that does not
 
  /// exist.
 
  unsigned BufferOverridden : 1;
 
 
 
  /// True if this content cache was initially created for a source file
 
  /// considered to be volatile (likely to change between stat and open).
 
  unsigned IsFileVolatile : 1;
 
 
 
  /// True if this file may be transient, that is, if it might not
 
  /// exist at some later point in time when this content entry is used,
 
  /// after serialization and deserialization.
 
  unsigned IsTransient : 1;
 
 
 
  mutable unsigned IsBufferInvalid : 1;
 
 
 
  ContentCache()
 
      : OrigEntry(std::nullopt), ContentsEntry(nullptr),
 
        BufferOverridden(false), IsFileVolatile(false), IsTransient(false),
 
        IsBufferInvalid(false) {}
 
 
 
  ContentCache(FileEntryRef Ent) : ContentCache(Ent, Ent) {}
 
 
 
  ContentCache(FileEntryRef Ent, const FileEntry *contentEnt)
 
      : OrigEntry(Ent), ContentsEntry(contentEnt), BufferOverridden(false),
 
        IsFileVolatile(false), IsTransient(false), IsBufferInvalid(false) {}
 
 
 
  /// The copy ctor does not allow copies where source object has either
 
  /// a non-NULL Buffer or SourceLineCache.  Ownership of allocated memory
 
  /// is not transferred, so this is a logical error.
 
  ContentCache(const ContentCache &RHS)
 
      : BufferOverridden(false), IsFileVolatile(false), IsTransient(false),
 
        IsBufferInvalid(false) {
 
    OrigEntry = RHS.OrigEntry;
 
    ContentsEntry = RHS.ContentsEntry;
 
 
 
    assert(!RHS.Buffer && !RHS.SourceLineCache &&
 
           "Passed ContentCache object cannot own a buffer.");
 
  }
 
 
 
  ContentCache &operator=(const ContentCache &RHS) = delete;
 
 
 
  /// Returns the memory buffer for the associated content.
 
  ///
 
  /// \param Diag Object through which diagnostics will be emitted if the
 
  ///   buffer cannot be retrieved.
 
  ///
 
  /// \param Loc If specified, is the location that invalid file diagnostics
 
  ///   will be emitted at.
 
  std::optional<llvm::MemoryBufferRef>
 
  getBufferOrNone(DiagnosticsEngine &Diag, FileManager &FM,
 
                  SourceLocation Loc = SourceLocation()) const;
 
 
 
  /// Returns the size of the content encapsulated by this
 
  /// ContentCache.
 
  ///
 
  /// This can be the size of the source file or the size of an
 
  /// arbitrary scratch buffer.  If the ContentCache encapsulates a source
 
  /// file this size is retrieved from the file's FileEntry.
 
  unsigned getSize() const;
 
 
 
  /// Returns the number of bytes actually mapped for this
 
  /// ContentCache.
 
  ///
 
  /// This can be 0 if the MemBuffer was not actually expanded.
 
  unsigned getSizeBytesMapped() const;
 
 
 
  /// Returns the kind of memory used to back the memory buffer for
 
  /// this content cache.  This is used for performance analysis.
 
  llvm::MemoryBuffer::BufferKind getMemoryBufferKind() const;
 
 
 
  /// Return the buffer, only if it has been loaded.
 
  std::optional<llvm::MemoryBufferRef> getBufferIfLoaded() const {
 
    if (Buffer)
 
      return Buffer->getMemBufferRef();
 
    return std::nullopt;
 
  }
 
 
 
  /// Return a StringRef to the source buffer data, only if it has already
 
  /// been loaded.
 
  std::optional<StringRef> getBufferDataIfLoaded() const {
 
    if (Buffer)
 
      return Buffer->getBuffer();
 
    return std::nullopt;
 
  }
 
 
 
  /// Set the buffer.
 
  void setBuffer(std::unique_ptr<llvm::MemoryBuffer> B) {
 
    IsBufferInvalid = false;
 
    Buffer = std::move(B);
 
  }
 
 
 
  /// Set the buffer to one that's not owned (or to nullptr).
 
  ///
 
  /// \pre Buffer cannot already be set.
 
  void setUnownedBuffer(std::optional<llvm::MemoryBufferRef> B) {
 
    assert(!Buffer && "Expected to be called right after construction");
 
    if (B)
 
      setBuffer(llvm::MemoryBuffer::getMemBuffer(*B));
 
  }
 
 
 
  // If BufStr has an invalid BOM, returns the BOM name; otherwise, returns
 
  // nullptr
 
  static const char *getInvalidBOM(StringRef BufStr);
 
};
 
 
 
// Assert that the \c ContentCache objects will always be 8-byte aligned so
 
// that we can pack 3 bits of integer into pointers to such objects.
 
static_assert(alignof(ContentCache) >= 8,
 
              "ContentCache must be 8-byte aligned.");
 
 
 
/// Information about a FileID, basically just the logical file
 
/// that it represents and include stack information.
 
///
 
/// Each FileInfo has include stack information, indicating where it came
 
/// from. This information encodes the \#include chain that a token was
 
/// expanded from. The main include file has an invalid IncludeLoc.
 
///
 
/// FileInfo should not grow larger than ExpansionInfo. Doing so will
 
/// cause memory to bloat in compilations with many unloaded macro
 
/// expansions, since the two data structurs are stored in a union in
 
/// SLocEntry. Extra fields should instead go in "ContentCache *", which
 
/// stores file contents and other bits on the side.
 
///
 
class FileInfo {
 
  friend class clang::SourceManager;
 
  friend class clang::ASTWriter;
 
  friend class clang::ASTReader;
 
 
 
  /// The location of the \#include that brought in this file.
 
  ///
 
  /// This is an invalid SLOC for the main file (top of the \#include chain).
 
  SourceLocation IncludeLoc;
 
 
 
  /// Number of FileIDs (files and macros) that were created during
 
  /// preprocessing of this \#include, including this SLocEntry.
 
  ///
 
  /// Zero means the preprocessor didn't provide such info for this SLocEntry.
 
  unsigned NumCreatedFIDs : 31;
 
 
 
  /// Whether this FileInfo has any \#line directives.
 
  unsigned HasLineDirectives : 1;
 
 
 
  /// The content cache and the characteristic of the file.
 
  llvm::PointerIntPair<const ContentCache *, 3, CharacteristicKind>
 
      ContentAndKind;
 
 
 
public:
 
  /// Return a FileInfo object.
 
  static FileInfo get(SourceLocation IL, ContentCache &Con,
 
                      CharacteristicKind FileCharacter, StringRef Filename) {
 
    FileInfo X;
 
    X.IncludeLoc = IL;
 
    X.NumCreatedFIDs = 0;
 
    X.HasLineDirectives = false;
 
    X.ContentAndKind.setPointer(&Con);
 
    X.ContentAndKind.setInt(FileCharacter);
 
    Con.Filename = Filename;
 
    return X;
 
  }
 
 
 
  SourceLocation getIncludeLoc() const {
 
    return IncludeLoc;
 
  }
 
 
 
  const ContentCache &getContentCache() const {
 
    return *ContentAndKind.getPointer();
 
  }
 
 
 
  /// Return whether this is a system header or not.
 
  CharacteristicKind getFileCharacteristic() const {
 
    return ContentAndKind.getInt();
 
  }
 
 
 
  /// Return true if this FileID has \#line directives in it.
 
  bool hasLineDirectives() const { return HasLineDirectives; }
 
 
 
  /// Set the flag that indicates that this FileID has
 
  /// line table entries associated with it.
 
  void setHasLineDirectives() { HasLineDirectives = true; }
 
 
 
  /// Returns the name of the file that was used when the file was loaded from
 
  /// the underlying file system.
 
  StringRef getName() const { return getContentCache().Filename; }
 
};
 
 
 
/// Each ExpansionInfo encodes the expansion location - where
 
/// the token was ultimately expanded, and the SpellingLoc - where the actual
 
/// character data for the token came from.
 
class ExpansionInfo {
 
  // Really these are all SourceLocations.
 
 
 
  /// Where the spelling for the token can be found.
 
  SourceLocation SpellingLoc;
 
 
 
  /// In a macro expansion, ExpansionLocStart and ExpansionLocEnd
 
  /// indicate the start and end of the expansion. In object-like macros,
 
  /// they will be the same. In a function-like macro expansion, the start
 
  /// will be the identifier and the end will be the ')'. Finally, in
 
  /// macro-argument instantiations, the end will be 'SourceLocation()', an
 
  /// invalid location.
 
  SourceLocation ExpansionLocStart, ExpansionLocEnd;
 
 
 
  /// Whether the expansion range is a token range.
 
  bool ExpansionIsTokenRange;
 
 
 
public:
 
  SourceLocation getSpellingLoc() const {
 
    return SpellingLoc.isInvalid() ? getExpansionLocStart() : SpellingLoc;
 
  }
 
 
 
  SourceLocation getExpansionLocStart() const {
 
    return ExpansionLocStart;
 
  }
 
 
 
  SourceLocation getExpansionLocEnd() const {
 
    return ExpansionLocEnd.isInvalid() ? getExpansionLocStart()
 
                                       : ExpansionLocEnd;
 
  }
 
 
 
  bool isExpansionTokenRange() const { return ExpansionIsTokenRange; }
 
 
 
  CharSourceRange getExpansionLocRange() const {
 
    return CharSourceRange(
 
        SourceRange(getExpansionLocStart(), getExpansionLocEnd()),
 
        isExpansionTokenRange());
 
  }
 
 
 
  bool isMacroArgExpansion() const {
 
    // Note that this needs to return false for default constructed objects.
 
    return getExpansionLocStart().isValid() && ExpansionLocEnd.isInvalid();
 
  }
 
 
 
  bool isMacroBodyExpansion() const {
 
    return getExpansionLocStart().isValid() && ExpansionLocEnd.isValid();
 
  }
 
 
 
  bool isFunctionMacroExpansion() const {
 
    return getExpansionLocStart().isValid() &&
 
           getExpansionLocStart() != getExpansionLocEnd();
 
  }
 
 
 
  /// Return a ExpansionInfo for an expansion.
 
  ///
 
  /// Start and End specify the expansion range (where the macro is
 
  /// expanded), and SpellingLoc specifies the spelling location (where
 
  /// the characters from the token come from). All three can refer to
 
  /// normal File SLocs or expansion locations.
 
  static ExpansionInfo create(SourceLocation SpellingLoc, SourceLocation Start,
 
                              SourceLocation End,
 
                              bool ExpansionIsTokenRange = true) {
 
    ExpansionInfo X;
 
    X.SpellingLoc = SpellingLoc;
 
    X.ExpansionLocStart = Start;
 
    X.ExpansionLocEnd = End;
 
    X.ExpansionIsTokenRange = ExpansionIsTokenRange;
 
    return X;
 
  }
 
 
 
  /// Return a special ExpansionInfo for the expansion of
 
  /// a macro argument into a function-like macro's body.
 
  ///
 
  /// ExpansionLoc specifies the expansion location (where the macro is
 
  /// expanded). This doesn't need to be a range because a macro is always
 
  /// expanded at a macro parameter reference, and macro parameters are
 
  /// always exactly one token. SpellingLoc specifies the spelling location
 
  /// (where the characters from the token come from). ExpansionLoc and
 
  /// SpellingLoc can both refer to normal File SLocs or expansion locations.
 
  ///
 
  /// Given the code:
 
  /// \code
 
  ///   #define F(x) f(x)
 
  ///   F(42);
 
  /// \endcode
 
  ///
 
  /// When expanding '\c F(42)', the '\c x' would call this with an
 
  /// SpellingLoc pointing at '\c 42' and an ExpansionLoc pointing at its
 
  /// location in the definition of '\c F'.
 
  static ExpansionInfo createForMacroArg(SourceLocation SpellingLoc,
 
                                         SourceLocation ExpansionLoc) {
 
    // We store an intentionally invalid source location for the end of the
 
    // expansion range to mark that this is a macro argument location rather
 
    // than a normal one.
 
    return create(SpellingLoc, ExpansionLoc, SourceLocation());
 
  }
 
 
 
  /// Return a special ExpansionInfo representing a token that ends
 
  /// prematurely. This is used to model a '>>' token that has been split
 
  /// into '>' tokens and similar cases. Unlike for the other forms of
 
  /// expansion, the expansion range in this case is a character range, not
 
  /// a token range.
 
  static ExpansionInfo createForTokenSplit(SourceLocation SpellingLoc,
 
                                           SourceLocation Start,
 
                                           SourceLocation End) {
 
    return create(SpellingLoc, Start, End, false);
 
  }
 
};
 
 
 
// Assert that the \c FileInfo objects are no bigger than \c ExpansionInfo
 
// objects. This controls the size of \c SLocEntry, of which we have one for
 
// each macro expansion. The number of (unloaded) macro expansions can be
 
// very large. Any other fields needed in FileInfo should go in ContentCache.
 
static_assert(sizeof(FileInfo) <= sizeof(ExpansionInfo),
 
              "FileInfo must be no larger than ExpansionInfo.");
 
 
 
/// This is a discriminated union of FileInfo and ExpansionInfo.
 
///
 
/// SourceManager keeps an array of these objects, and they are uniquely
 
/// identified by the FileID datatype.
 
class SLocEntry {
 
  static constexpr int OffsetBits = 8 * sizeof(SourceLocation::UIntTy) - 1;
 
  SourceLocation::UIntTy Offset : OffsetBits;
 
  SourceLocation::UIntTy IsExpansion : 1;
 
  union {
 
    FileInfo File;
 
    ExpansionInfo Expansion;
 
  };
 
 
 
public:
 
  SLocEntry() : Offset(), IsExpansion(), File() {}
 
 
 
  SourceLocation::UIntTy getOffset() const { return Offset; }
 
 
 
  bool isExpansion() const { return IsExpansion; }
 
  bool isFile() const { return !isExpansion(); }
 
 
 
  const FileInfo &getFile() const {
 
    assert(isFile() && "Not a file SLocEntry!");
 
    return File;
 
  }
 
 
 
  const ExpansionInfo &getExpansion() const {
 
    assert(isExpansion() && "Not a macro expansion SLocEntry!");
 
    return Expansion;
 
  }
 
 
 
  static SLocEntry get(SourceLocation::UIntTy Offset, const FileInfo &FI) {
 
    assert(!(Offset & (1ULL << OffsetBits)) && "Offset is too large");
 
    SLocEntry E;
 
    E.Offset = Offset;
 
    E.IsExpansion = false;
 
    E.File = FI;
 
    return E;
 
  }
 
 
 
  static SLocEntry get(SourceLocation::UIntTy Offset,
 
                       const ExpansionInfo &Expansion) {
 
    assert(!(Offset & (1ULL << OffsetBits)) && "Offset is too large");
 
    SLocEntry E;
 
    E.Offset = Offset;
 
    E.IsExpansion = true;
 
    new (&E.Expansion) ExpansionInfo(Expansion);
 
    return E;
 
  }
 
};
 
 
 
} // namespace SrcMgr
 
 
 
/// External source of source location entries.
 
class ExternalSLocEntrySource {
 
public:
 
  virtual ~ExternalSLocEntrySource();
 
 
 
  /// Read the source location entry with index ID, which will always be
 
  /// less than -1.
 
  ///
 
  /// \returns true if an error occurred that prevented the source-location
 
  /// entry from being loaded.
 
  virtual bool ReadSLocEntry(int ID) = 0;
 
 
 
  /// Retrieve the module import location and name for the given ID, if
 
  /// in fact it was loaded from a module (rather than, say, a precompiled
 
  /// header).
 
  virtual std::pair<SourceLocation, StringRef> getModuleImportLoc(int ID) = 0;
 
};
 
 
 
/// Holds the cache used by isBeforeInTranslationUnit.
 
///
 
/// The cache structure is complex enough to be worth breaking out of
 
/// SourceManager.
 
class InBeforeInTUCacheEntry {
 
  /// The FileID's of the cached query.
 
  ///
 
  /// If these match up with a subsequent query, the result can be reused.
 
  FileID LQueryFID, RQueryFID;
 
 
 
  /// The relative order of FileIDs that the CommonFID *immediately* includes.
 
  ///
 
  /// This is used to compare macro expansion locations.
 
  bool LChildBeforeRChild;
 
 
 
  /// The file found in common between the two \#include traces, i.e.,
 
  /// the nearest common ancestor of the \#include tree.
 
  FileID CommonFID;
 
 
 
  /// The offset of the previous query in CommonFID.
 
  ///
 
  /// Usually, this represents the location of the \#include for QueryFID, but
 
  /// if LQueryFID is a parent of RQueryFID (or vice versa) then these can be a
 
  /// random token in the parent.
 
  unsigned LCommonOffset, RCommonOffset;
 
 
 
public:
 
  InBeforeInTUCacheEntry() = default;
 
  InBeforeInTUCacheEntry(FileID L, FileID R) : LQueryFID(L), RQueryFID(R) {
 
    assert(L != R);
 
  }
 
 
 
  /// Return true if the currently cached values match up with
 
  /// the specified LHS/RHS query.
 
  ///
 
  /// If not, we can't use the cache.
 
  bool isCacheValid() const {
 
    return CommonFID.isValid();
 
  }
 
 
 
  /// If the cache is valid, compute the result given the
 
  /// specified offsets in the LHS/RHS FileID's.
 
  bool getCachedResult(unsigned LOffset, unsigned ROffset) const {
 
    // If one of the query files is the common file, use the offset.  Otherwise,
 
    // use the #include loc in the common file.
 
    if (LQueryFID != CommonFID) LOffset = LCommonOffset;
 
    if (RQueryFID != CommonFID) ROffset = RCommonOffset;
 
 
 
    // It is common for multiple macro expansions to be "included" from the same
 
    // location (expansion location), in which case use the order of the FileIDs
 
    // to determine which came first. This will also take care the case where
 
    // one of the locations points at the inclusion/expansion point of the other
 
    // in which case its FileID will come before the other.
 
    if (LOffset == ROffset)
 
      return LChildBeforeRChild;
 
 
 
    return LOffset < ROffset;
 
  }
 
 
 
  /// Set up a new query.
 
  /// If it matches the old query, we can keep the cached answer.
 
  void setQueryFIDs(FileID LHS, FileID RHS) {
 
    assert(LHS != RHS);
 
    if (LQueryFID != LHS || RQueryFID != RHS) {
 
      LQueryFID = LHS;
 
      RQueryFID = RHS;
 
      CommonFID = FileID();
 
    }
 
  }
 
 
 
  void setCommonLoc(FileID commonFID, unsigned lCommonOffset,
 
                    unsigned rCommonOffset, bool LParentBeforeRParent) {
 
    CommonFID = commonFID;
 
    LCommonOffset = lCommonOffset;
 
    RCommonOffset = rCommonOffset;
 
    LChildBeforeRChild = LParentBeforeRParent;
 
  }
 
};
 
 
 
/// The stack used when building modules on demand, which is used
 
/// to provide a link between the source managers of the different compiler
 
/// instances.
 
using ModuleBuildStack = ArrayRef<std::pair<std::string, FullSourceLoc>>;
 
 
 
/// This class handles loading and caching of source files into memory.
 
///
 
/// This object owns the MemoryBuffer objects for all of the loaded
 
/// files and assigns unique FileID's for each unique \#include chain.
 
///
 
/// The SourceManager can be queried for information about SourceLocation
 
/// objects, turning them into either spelling or expansion locations. Spelling
 
/// locations represent where the bytes corresponding to a token came from and
 
/// expansion locations represent where the location is in the user's view. In
 
/// the case of a macro expansion, for example, the spelling location indicates
 
/// where the expanded token came from and the expansion location specifies
 
/// where it was expanded.
 
class SourceManager : public RefCountedBase<SourceManager> {
 
  /// DiagnosticsEngine object.
 
  DiagnosticsEngine &Diag;
 
 
 
  FileManager &FileMgr;
 
 
 
  mutable llvm::BumpPtrAllocator ContentCacheAlloc;
 
 
 
  /// Memoized information about all of the files tracked by this
 
  /// SourceManager.
 
  ///
 
  /// This map allows us to merge ContentCache entries based
 
  /// on their FileEntry*.  All ContentCache objects will thus have unique,
 
  /// non-null, FileEntry pointers.
 
  llvm::DenseMap<const FileEntry*, SrcMgr::ContentCache*> FileInfos;
 
 
 
  /// True if the ContentCache for files that are overridden by other
 
  /// files, should report the original file name. Defaults to true.
 
  bool OverridenFilesKeepOriginalName = true;
 
 
 
  /// True if non-system source files should be treated as volatile
 
  /// (likely to change while trying to use them). Defaults to false.
 
  bool UserFilesAreVolatile;
 
 
 
  /// True if all files read during this compilation should be treated
 
  /// as transient (may not be present in later compilations using a module
 
  /// file created from this compilation). Defaults to false.
 
  bool FilesAreTransient = false;
 
 
 
  struct OverriddenFilesInfoTy {
 
    /// Files that have been overridden with the contents from another
 
    /// file.
 
    llvm::DenseMap<const FileEntry *, FileEntryRef> OverriddenFiles;
 
 
 
    /// Files that were overridden with a memory buffer.
 
    llvm::DenseSet<const FileEntry *> OverriddenFilesWithBuffer;
 
  };
 
 
 
  /// Lazily create the object keeping overridden files info, since
 
  /// it is uncommonly used.
 
  std::unique_ptr<OverriddenFilesInfoTy> OverriddenFilesInfo;
 
 
 
  OverriddenFilesInfoTy &getOverriddenFilesInfo() {
 
    if (!OverriddenFilesInfo)
 
      OverriddenFilesInfo.reset(new OverriddenFilesInfoTy);
 
    return *OverriddenFilesInfo;
 
  }
 
 
 
  /// Information about various memory buffers that we have read in.
 
  ///
 
  /// All FileEntry* within the stored ContentCache objects are NULL,
 
  /// as they do not refer to a file.
 
  std::vector<SrcMgr::ContentCache*> MemBufferInfos;
 
 
 
  /// The table of SLocEntries that are local to this module.
 
  ///
 
  /// Positive FileIDs are indexes into this table. Entry 0 indicates an invalid
 
  /// expansion.
 
  SmallVector<SrcMgr::SLocEntry, 0> LocalSLocEntryTable;
 
 
 
  /// The table of SLocEntries that are loaded from other modules.
 
  ///
 
  /// Negative FileIDs are indexes into this table. To get from ID to an index,
 
  /// use (-ID - 2).
 
  SmallVector<SrcMgr::SLocEntry, 0> LoadedSLocEntryTable;
 
 
 
  /// The starting offset of the next local SLocEntry.
 
  ///
 
  /// This is LocalSLocEntryTable.back().Offset + the size of that entry.
 
  SourceLocation::UIntTy NextLocalOffset;
 
 
 
  /// The starting offset of the latest batch of loaded SLocEntries.
 
  ///
 
  /// This is LoadedSLocEntryTable.back().Offset, except that that entry might
 
  /// not have been loaded, so that value would be unknown.
 
  SourceLocation::UIntTy CurrentLoadedOffset;
 
 
 
  /// The highest possible offset is 2^31-1 (2^63-1 for 64-bit source
 
  /// locations), so CurrentLoadedOffset starts at 2^31 (2^63 resp.).
 
  static const SourceLocation::UIntTy MaxLoadedOffset =
 
      1ULL << (8 * sizeof(SourceLocation::UIntTy) - 1);
 
 
 
  /// A bitmap that indicates whether the entries of LoadedSLocEntryTable
 
  /// have already been loaded from the external source.
 
  ///
 
  /// Same indexing as LoadedSLocEntryTable.
 
  llvm::BitVector SLocEntryLoaded;
 
 
 
  /// An external source for source location entries.
 
  ExternalSLocEntrySource *ExternalSLocEntries = nullptr;
 
 
 
  /// A one-entry cache to speed up getFileID.
 
  ///
 
  /// LastFileIDLookup records the last FileID looked up or created, because it
 
  /// is very common to look up many tokens from the same file.
 
  mutable FileID LastFileIDLookup;
 
 
 
  /// Holds information for \#line directives.
 
  ///
 
  /// This is referenced by indices from SLocEntryTable.
 
  std::unique_ptr<LineTableInfo> LineTable;
 
 
 
  /// These ivars serve as a cache used in the getLineNumber
 
  /// method which is used to speedup getLineNumber calls to nearby locations.
 
  mutable FileID LastLineNoFileIDQuery;
 
  mutable const SrcMgr::ContentCache *LastLineNoContentCache;
 
  mutable unsigned LastLineNoFilePos;
 
  mutable unsigned LastLineNoResult;
 
 
 
  /// The file ID for the main source file of the translation unit.
 
  FileID MainFileID;
 
 
 
  /// The file ID for the precompiled preamble there is one.
 
  FileID PreambleFileID;
 
 
 
  // Statistics for -print-stats.
 
  mutable unsigned NumLinearScans = 0;
 
  mutable unsigned NumBinaryProbes = 0;
 
 
 
  /// Associates a FileID with its "included/expanded in" decomposed
 
  /// location.
 
  ///
 
  /// Used to cache results from and speed-up \c getDecomposedIncludedLoc
 
  /// function.
 
  mutable llvm::DenseMap<FileID, std::pair<FileID, unsigned>> IncludedLocMap;
 
 
 
  /// The key value into the IsBeforeInTUCache table.
 
  using IsBeforeInTUCacheKey = std::pair<FileID, FileID>;
 
 
 
  /// The IsBeforeInTranslationUnitCache is a mapping from FileID pairs
 
  /// to cache results.
 
  using InBeforeInTUCache =
 
      llvm::DenseMap<IsBeforeInTUCacheKey, InBeforeInTUCacheEntry>;
 
 
 
  /// Cache results for the isBeforeInTranslationUnit method.
 
  mutable InBeforeInTUCache IBTUCache;
 
  mutable InBeforeInTUCacheEntry IBTUCacheOverflow;
 
 
 
  /// Return the cache entry for comparing the given file IDs
 
  /// for isBeforeInTranslationUnit.
 
  InBeforeInTUCacheEntry &getInBeforeInTUCache(FileID LFID, FileID RFID) const;
 
 
 
  // Cache for the "fake" buffer used for error-recovery purposes.
 
  mutable std::unique_ptr<llvm::MemoryBuffer> FakeBufferForRecovery;
 
 
 
  mutable std::unique_ptr<SrcMgr::ContentCache> FakeContentCacheForRecovery;
 
 
 
  mutable std::unique_ptr<SrcMgr::SLocEntry> FakeSLocEntryForRecovery;
 
 
 
  /// Lazily computed map of macro argument chunks to their expanded
 
  /// source location.
 
  using MacroArgsMap = std::map<unsigned, SourceLocation>;
 
 
 
  mutable llvm::DenseMap<FileID, std::unique_ptr<MacroArgsMap>>
 
      MacroArgsCacheMap;
 
 
 
  /// The stack of modules being built, which is used to detect
 
  /// cycles in the module dependency graph as modules are being built, as
 
  /// well as to describe why we're rebuilding a particular module.
 
  ///
 
  /// There is no way to set this value from the command line. If we ever need
 
  /// to do so (e.g., if on-demand module construction moves out-of-process),
 
  /// we can add a cc1-level option to do so.
 
  SmallVector<std::pair<std::string, FullSourceLoc>, 2> StoredModuleBuildStack;
 
 
 
public:
 
  SourceManager(DiagnosticsEngine &Diag, FileManager &FileMgr,
 
                bool UserFilesAreVolatile = false);
 
  explicit SourceManager(const SourceManager &) = delete;
 
  SourceManager &operator=(const SourceManager &) = delete;
 
  ~SourceManager();
 
 
 
  void clearIDTables();
 
 
 
  /// Initialize this source manager suitably to replay the compilation
 
  /// described by \p Old. Requires that \p Old outlive \p *this.
 
  void initializeForReplay(const SourceManager &Old);
 
 
 
  DiagnosticsEngine &getDiagnostics() const { return Diag; }
 
 
 
  FileManager &getFileManager() const { return FileMgr; }
 
 
 
  /// Set true if the SourceManager should report the original file name
 
  /// for contents of files that were overridden by other files. Defaults to
 
  /// true.
 
  void setOverridenFilesKeepOriginalName(bool value) {
 
    OverridenFilesKeepOriginalName = value;
 
  }
 
 
 
  /// True if non-system source files should be treated as volatile
 
  /// (likely to change while trying to use them).
 
  bool userFilesAreVolatile() const { return UserFilesAreVolatile; }
 
 
 
  /// Retrieve the module build stack.
 
  ModuleBuildStack getModuleBuildStack() const {
 
    return StoredModuleBuildStack;
 
  }
 
 
 
  /// Set the module build stack.
 
  void setModuleBuildStack(ModuleBuildStack stack) {
 
    StoredModuleBuildStack.clear();
 
    StoredModuleBuildStack.append(stack.begin(), stack.end());
 
  }
 
 
 
  /// Push an entry to the module build stack.
 
  void pushModuleBuildStack(StringRef moduleName, FullSourceLoc importLoc) {
 
    StoredModuleBuildStack.push_back(std::make_pair(moduleName.str(),importLoc));
 
  }
 
 
 
  //===--------------------------------------------------------------------===//
 
  // MainFileID creation and querying methods.
 
  //===--------------------------------------------------------------------===//
 
 
 
  /// Returns the FileID of the main source file.
 
  FileID getMainFileID() const { return MainFileID; }
 
 
 
  /// Set the file ID for the main source file.
 
  void setMainFileID(FileID FID) {
 
    MainFileID = FID;
 
  }
 
 
 
  /// Returns true when the given FileEntry corresponds to the main file.
 
  ///
 
  /// The main file should be set prior to calling this function.
 
  bool isMainFile(const FileEntry &SourceFile);
 
 
 
  /// Set the file ID for the precompiled preamble.
 
  void setPreambleFileID(FileID Preamble) {
 
    assert(PreambleFileID.isInvalid() && "PreambleFileID already set!");
 
    PreambleFileID = Preamble;
 
  }
 
 
 
  /// Get the file ID for the precompiled preamble if there is one.
 
  FileID getPreambleFileID() const { return PreambleFileID; }
 
 
 
  //===--------------------------------------------------------------------===//
 
  // Methods to create new FileID's and macro expansions.
 
  //===--------------------------------------------------------------------===//
 
 
 
  /// Create a new FileID that represents the specified file
 
  /// being \#included from the specified IncludePosition.
 
  ///
 
  /// This translates NULL into standard input.
 
  FileID createFileID(const FileEntry *SourceFile, SourceLocation IncludePos,
 
                      SrcMgr::CharacteristicKind FileCharacter,
 
                      int LoadedID = 0,
 
                      SourceLocation::UIntTy LoadedOffset = 0);
 
 
 
  FileID createFileID(FileEntryRef SourceFile, SourceLocation IncludePos,
 
                      SrcMgr::CharacteristicKind FileCharacter,
 
                      int LoadedID = 0,
 
                      SourceLocation::UIntTy LoadedOffset = 0);
 
 
 
  /// Create a new FileID that represents the specified memory buffer.
 
  ///
 
  /// This does no caching of the buffer and takes ownership of the
 
  /// MemoryBuffer, so only pass a MemoryBuffer to this once.
 
  FileID createFileID(std::unique_ptr<llvm::MemoryBuffer> Buffer,
 
                      SrcMgr::CharacteristicKind FileCharacter = SrcMgr::C_User,
 
                      int LoadedID = 0, SourceLocation::UIntTy LoadedOffset = 0,
 
                      SourceLocation IncludeLoc = SourceLocation());
 
 
 
  /// Create a new FileID that represents the specified memory buffer.
 
  ///
 
  /// This does not take ownership of the MemoryBuffer. The memory buffer must
 
  /// outlive the SourceManager.
 
  FileID createFileID(const llvm::MemoryBufferRef &Buffer,
 
                      SrcMgr::CharacteristicKind FileCharacter = SrcMgr::C_User,
 
                      int LoadedID = 0, SourceLocation::UIntTy LoadedOffset = 0,
 
                      SourceLocation IncludeLoc = SourceLocation());
 
 
 
  /// Get the FileID for \p SourceFile if it exists. Otherwise, create a
 
  /// new FileID for the \p SourceFile.
 
  FileID getOrCreateFileID(const FileEntry *SourceFile,
 
                           SrcMgr::CharacteristicKind FileCharacter);
 
 
 
  /// Creates an expansion SLocEntry for the substitution of an argument into a
 
  /// function-like macro's body. Returns the start of the expansion.
 
  ///
 
  /// The macro argument was written at \p SpellingLoc with length \p Length.
 
  /// \p ExpansionLoc is the parameter name in the (expanded) macro body.
 
  SourceLocation createMacroArgExpansionLoc(SourceLocation SpellingLoc,
 
                                            SourceLocation ExpansionLoc,
 
                                            unsigned Length);
 
 
 
  /// Creates an expansion SLocEntry for a macro use. Returns its start.
 
  ///
 
  /// The macro body begins at \p SpellingLoc with length \p Length.
 
  /// The macro use spans [ExpansionLocStart, ExpansionLocEnd].
 
  SourceLocation createExpansionLoc(SourceLocation SpellingLoc,
 
                                    SourceLocation ExpansionLocStart,
 
                                    SourceLocation ExpansionLocEnd,
 
                                    unsigned Length,
 
                                    bool ExpansionIsTokenRange = true,
 
                                    int LoadedID = 0,
 
                                    SourceLocation::UIntTy LoadedOffset = 0);
 
 
 
  /// Return a new SourceLocation that encodes that the token starting
 
  /// at \p TokenStart ends prematurely at \p TokenEnd.
 
  SourceLocation createTokenSplitLoc(SourceLocation SpellingLoc,
 
                                     SourceLocation TokenStart,
 
                                     SourceLocation TokenEnd);
 
 
 
  /// Retrieve the memory buffer associated with the given file.
 
  ///
 
  /// Returns std::nullopt if the buffer is not valid.
 
  std::optional<llvm::MemoryBufferRef>
 
  getMemoryBufferForFileOrNone(const FileEntry *File);
 
 
 
  /// Retrieve the memory buffer associated with the given file.
 
  ///
 
  /// Returns a fake buffer if there isn't a real one.
 
  llvm::MemoryBufferRef getMemoryBufferForFileOrFake(const FileEntry *File) {
 
    if (auto B = getMemoryBufferForFileOrNone(File))
 
      return *B;
 
    return getFakeBufferForRecovery();
 
  }
 
 
 
  /// Override the contents of the given source file by providing an
 
  /// already-allocated buffer.
 
  ///
 
  /// \param SourceFile the source file whose contents will be overridden.
 
  ///
 
  /// \param Buffer the memory buffer whose contents will be used as the
 
  /// data in the given source file.
 
  void overrideFileContents(const FileEntry *SourceFile,
 
                            const llvm::MemoryBufferRef &Buffer) {
 
    overrideFileContents(SourceFile, llvm::MemoryBuffer::getMemBuffer(Buffer));
 
  }
 
 
 
  /// Override the contents of the given source file by providing an
 
  /// already-allocated buffer.
 
  ///
 
  /// \param SourceFile the source file whose contents will be overridden.
 
  ///
 
  /// \param Buffer the memory buffer whose contents will be used as the
 
  /// data in the given source file.
 
  void overrideFileContents(const FileEntry *SourceFile,
 
                            std::unique_ptr<llvm::MemoryBuffer> Buffer);
 
  void overrideFileContents(FileEntryRef SourceFile,
 
                            std::unique_ptr<llvm::MemoryBuffer> Buffer) {
 
    overrideFileContents(&SourceFile.getFileEntry(), std::move(Buffer));
 
  }
 
 
 
  /// Override the given source file with another one.
 
  ///
 
  /// \param SourceFile the source file which will be overridden.
 
  ///
 
  /// \param NewFile the file whose contents will be used as the
 
  /// data instead of the contents of the given source file.
 
  void overrideFileContents(const FileEntry *SourceFile, FileEntryRef NewFile);
 
 
 
  /// Returns true if the file contents have been overridden.
 
  bool isFileOverridden(const FileEntry *File) const {
 
    if (OverriddenFilesInfo) {
 
      if (OverriddenFilesInfo->OverriddenFilesWithBuffer.count(File))
 
        return true;
 
      if (OverriddenFilesInfo->OverriddenFiles.find(File) !=
 
          OverriddenFilesInfo->OverriddenFiles.end())
 
        return true;
 
    }
 
    return false;
 
  }
 
 
 
  /// Bypass the overridden contents of a file.  This creates a new FileEntry
 
  /// and initializes the content cache for it.  Returns std::nullopt if there
 
  /// is no such file in the filesystem.
 
  ///
 
  /// This should be called before parsing has begun.
 
  OptionalFileEntryRef bypassFileContentsOverride(FileEntryRef File);
 
 
 
  /// Specify that a file is transient.
 
  void setFileIsTransient(const FileEntry *SourceFile);
 
 
 
  /// Specify that all files that are read during this compilation are
 
  /// transient.
 
  void setAllFilesAreTransient(bool Transient) {
 
    FilesAreTransient = Transient;
 
  }
 
 
 
  //===--------------------------------------------------------------------===//
 
  // FileID manipulation methods.
 
  //===--------------------------------------------------------------------===//
 
 
 
  /// Return the buffer for the specified FileID.
 
  ///
 
  /// If there is an error opening this buffer the first time, return
 
  /// std::nullopt.
 
  std::optional<llvm::MemoryBufferRef>
 
  getBufferOrNone(FileID FID, SourceLocation Loc = SourceLocation()) const {
 
    if (auto *Entry = getSLocEntryForFile(FID))
 
      return Entry->getFile().getContentCache().getBufferOrNone(
 
          Diag, getFileManager(), Loc);
 
    return std::nullopt;
 
  }
 
 
 
  /// Return the buffer for the specified FileID.
 
  ///
 
  /// If there is an error opening this buffer the first time, this
 
  /// manufactures a temporary buffer and returns it.
 
  llvm::MemoryBufferRef
 
  getBufferOrFake(FileID FID, SourceLocation Loc = SourceLocation()) const {
 
    if (auto B = getBufferOrNone(FID, Loc))
 
      return *B;
 
    return getFakeBufferForRecovery();
 
  }
 
 
 
  /// Returns the FileEntry record for the provided FileID.
 
  const FileEntry *getFileEntryForID(FileID FID) const {
 
    if (auto *Entry = getSLocEntryForFile(FID))
 
      return Entry->getFile().getContentCache().OrigEntry;
 
    return nullptr;
 
  }
 
 
 
  /// Returns the FileEntryRef for the provided FileID.
 
  OptionalFileEntryRef getFileEntryRefForID(FileID FID) const {
 
    if (auto *Entry = getSLocEntryForFile(FID))
 
      return Entry->getFile().getContentCache().OrigEntry;
 
    return std::nullopt;
 
  }
 
 
 
  /// Returns the filename for the provided FileID, unless it's a built-in
 
  /// buffer that's not represented by a filename.
 
  ///
 
  /// Returns std::nullopt for non-files and built-in files.
 
  std::optional<StringRef> getNonBuiltinFilenameForID(FileID FID) const;
 
 
 
  /// Returns the FileEntry record for the provided SLocEntry.
 
  const FileEntry *getFileEntryForSLocEntry(const SrcMgr::SLocEntry &sloc) const
 
  {
 
    return sloc.getFile().getContentCache().OrigEntry;
 
  }
 
 
 
  /// Return a StringRef to the source buffer data for the
 
  /// specified FileID.
 
  ///
 
  /// \param FID The file ID whose contents will be returned.
 
  /// \param Invalid If non-NULL, will be set true if an error occurred.
 
  StringRef getBufferData(FileID FID, bool *Invalid = nullptr) const;
 
 
 
  /// Return a StringRef to the source buffer data for the
 
  /// specified FileID, returning std::nullopt if invalid.
 
  ///
 
  /// \param FID The file ID whose contents will be returned.
 
  std::optional<StringRef> getBufferDataOrNone(FileID FID) const;
 
 
 
  /// Return a StringRef to the source buffer data for the
 
  /// specified FileID, returning std::nullopt if it's not yet loaded.
 
  ///
 
  /// \param FID The file ID whose contents will be returned.
 
  std::optional<StringRef> getBufferDataIfLoaded(FileID FID) const;
 
 
 
  /// Get the number of FileIDs (files and macros) that were created
 
  /// during preprocessing of \p FID, including it.
 
  unsigned getNumCreatedFIDsForFileID(FileID FID) const {
 
    if (auto *Entry = getSLocEntryForFile(FID))
 
      return Entry->getFile().NumCreatedFIDs;
 
    return 0;
 
  }
 
 
 
  /// Set the number of FileIDs (files and macros) that were created
 
  /// during preprocessing of \p FID, including it.
 
  void setNumCreatedFIDsForFileID(FileID FID, unsigned NumFIDs,
 
                                  bool Force = false) const {
 
    auto *Entry = getSLocEntryForFile(FID);
 
    if (!Entry)
 
      return;
 
    assert((Force || Entry->getFile().NumCreatedFIDs == 0) && "Already set!");
 
    const_cast<SrcMgr::FileInfo &>(Entry->getFile()).NumCreatedFIDs = NumFIDs;
 
  }
 
 
 
  //===--------------------------------------------------------------------===//
 
  // SourceLocation manipulation methods.
 
  //===--------------------------------------------------------------------===//
 
 
 
  /// Return the FileID for a SourceLocation.
 
  ///
 
  /// This is a very hot method that is used for all SourceManager queries
 
  /// that start with a SourceLocation object.  It is responsible for finding
 
  /// the entry in SLocEntryTable which contains the specified location.
 
  ///
 
  FileID getFileID(SourceLocation SpellingLoc) const {
 
    return getFileID(SpellingLoc.getOffset());
 
  }
 
 
 
  /// Return the filename of the file containing a SourceLocation.
 
  StringRef getFilename(SourceLocation SpellingLoc) const;
 
 
 
  /// Return the source location corresponding to the first byte of
 
  /// the specified file.
 
  SourceLocation getLocForStartOfFile(FileID FID) const {
 
    if (auto *Entry = getSLocEntryForFile(FID))
 
      return SourceLocation::getFileLoc(Entry->getOffset());
 
    return SourceLocation();
 
  }
 
 
 
  /// Return the source location corresponding to the last byte of the
 
  /// specified file.
 
  SourceLocation getLocForEndOfFile(FileID FID) const {
 
    if (auto *Entry = getSLocEntryForFile(FID))
 
      return SourceLocation::getFileLoc(Entry->getOffset() +
 
                                        getFileIDSize(FID));
 
    return SourceLocation();
 
  }
 
 
 
  /// Returns the include location if \p FID is a \#include'd file
 
  /// otherwise it returns an invalid location.
 
  SourceLocation getIncludeLoc(FileID FID) const {
 
    if (auto *Entry = getSLocEntryForFile(FID))
 
      return Entry->getFile().getIncludeLoc();
 
    return SourceLocation();
 
  }
 
 
 
  // Returns the import location if the given source location is
 
  // located within a module, or an invalid location if the source location
 
  // is within the current translation unit.
 
  std::pair<SourceLocation, StringRef>
 
  getModuleImportLoc(SourceLocation Loc) const {
 
    FileID FID = getFileID(Loc);
 
 
 
    // Positive file IDs are in the current translation unit, and -1 is a
 
    // placeholder.
 
    if (FID.ID >= -1)
 
      return std::make_pair(SourceLocation(), "");
 
 
 
    return ExternalSLocEntries->getModuleImportLoc(FID.ID);
 
  }
 
 
 
  /// Given a SourceLocation object \p Loc, return the expansion
 
  /// location referenced by the ID.
 
  SourceLocation getExpansionLoc(SourceLocation Loc) const {
 
    // Handle the non-mapped case inline, defer to out of line code to handle
 
    // expansions.
 
    if (Loc.isFileID()) return Loc;
 
    return getExpansionLocSlowCase(Loc);
 
  }
 
 
 
  /// Given \p Loc, if it is a macro location return the expansion
 
  /// location or the spelling location, depending on if it comes from a
 
  /// macro argument or not.
 
  SourceLocation getFileLoc(SourceLocation Loc) const {
 
    if (Loc.isFileID()) return Loc;
 
    return getFileLocSlowCase(Loc);
 
  }
 
 
 
  /// Return the start/end of the expansion information for an
 
  /// expansion location.
 
  ///
 
  /// \pre \p Loc is required to be an expansion location.
 
  CharSourceRange getImmediateExpansionRange(SourceLocation Loc) const;
 
 
 
  /// Given a SourceLocation object, return the range of
 
  /// tokens covered by the expansion in the ultimate file.
 
  CharSourceRange getExpansionRange(SourceLocation Loc) const;
 
 
 
  /// Given a SourceRange object, return the range of
 
  /// tokens or characters covered by the expansion in the ultimate file.
 
  CharSourceRange getExpansionRange(SourceRange Range) const {
 
    SourceLocation Begin = getExpansionRange(Range.getBegin()).getBegin();
 
    CharSourceRange End = getExpansionRange(Range.getEnd());
 
    return CharSourceRange(SourceRange(Begin, End.getEnd()),
 
                           End.isTokenRange());
 
  }
 
 
 
  /// Given a CharSourceRange object, return the range of
 
  /// tokens or characters covered by the expansion in the ultimate file.
 
  CharSourceRange getExpansionRange(CharSourceRange Range) const {
 
    CharSourceRange Expansion = getExpansionRange(Range.getAsRange());
 
    if (Expansion.getEnd() == Range.getEnd())
 
      Expansion.setTokenRange(Range.isTokenRange());
 
    return Expansion;
 
  }
 
 
 
  /// Given a SourceLocation object, return the spelling
 
  /// location referenced by the ID.
 
  ///
 
  /// This is the place where the characters that make up the lexed token
 
  /// can be found.
 
  SourceLocation getSpellingLoc(SourceLocation Loc) const {
 
    // Handle the non-mapped case inline, defer to out of line code to handle
 
    // expansions.
 
    if (Loc.isFileID()) return Loc;
 
    return getSpellingLocSlowCase(Loc);
 
  }
 
 
 
  /// Given a SourceLocation object, return the spelling location
 
  /// referenced by the ID.
 
  ///
 
  /// This is the first level down towards the place where the characters
 
  /// that make up the lexed token can be found.  This should not generally
 
  /// be used by clients.
 
  SourceLocation getImmediateSpellingLoc(SourceLocation Loc) const;
 
 
 
  /// Form a SourceLocation from a FileID and Offset pair.
 
  SourceLocation getComposedLoc(FileID FID, unsigned Offset) const {
 
    auto *Entry = getSLocEntryOrNull(FID);
 
    if (!Entry)
 
      return SourceLocation();
 
 
 
    SourceLocation::UIntTy GlobalOffset = Entry->getOffset() + Offset;
 
    return Entry->isFile() ? SourceLocation::getFileLoc(GlobalOffset)
 
                           : SourceLocation::getMacroLoc(GlobalOffset);
 
  }
 
 
 
  /// Decompose the specified location into a raw FileID + Offset pair.
 
  ///
 
  /// The first element is the FileID, the second is the offset from the
 
  /// start of the buffer of the location.
 
  std::pair<FileID, unsigned> getDecomposedLoc(SourceLocation Loc) const {
 
    FileID FID = getFileID(Loc);
 
    auto *Entry = getSLocEntryOrNull(FID);
 
    if (!Entry)
 
      return std::make_pair(FileID(), 0);
 
    return std::make_pair(FID, Loc.getOffset() - Entry->getOffset());
 
  }
 
 
 
  /// Decompose the specified location into a raw FileID + Offset pair.
 
  ///
 
  /// If the location is an expansion record, walk through it until we find
 
  /// the final location expanded.
 
  std::pair<FileID, unsigned>
 
  getDecomposedExpansionLoc(SourceLocation Loc) const {
 
    FileID FID = getFileID(Loc);
 
    auto *E = getSLocEntryOrNull(FID);
 
    if (!E)
 
      return std::make_pair(FileID(), 0);
 
 
 
    unsigned Offset = Loc.getOffset()-E->getOffset();
 
    if (Loc.isFileID())
 
      return std::make_pair(FID, Offset);
 
 
 
    return getDecomposedExpansionLocSlowCase(E);
 
  }
 
 
 
  /// Decompose the specified location into a raw FileID + Offset pair.
 
  ///
 
  /// If the location is an expansion record, walk through it until we find
 
  /// its spelling record.
 
  std::pair<FileID, unsigned>
 
  getDecomposedSpellingLoc(SourceLocation Loc) const {
 
    FileID FID = getFileID(Loc);
 
    auto *E = getSLocEntryOrNull(FID);
 
    if (!E)
 
      return std::make_pair(FileID(), 0);
 
 
 
    unsigned Offset = Loc.getOffset()-E->getOffset();
 
    if (Loc.isFileID())
 
      return std::make_pair(FID, Offset);
 
    return getDecomposedSpellingLocSlowCase(E, Offset);
 
  }
 
 
 
  /// Returns the "included/expanded in" decomposed location of the given
 
  /// FileID.
 
  std::pair<FileID, unsigned> getDecomposedIncludedLoc(FileID FID) const;
 
 
 
  /// Returns the offset from the start of the file that the
 
  /// specified SourceLocation represents.
 
  ///
 
  /// This is not very meaningful for a macro ID.
 
  unsigned getFileOffset(SourceLocation SpellingLoc) const {
 
    return getDecomposedLoc(SpellingLoc).second;
 
  }
 
 
 
  /// Tests whether the given source location represents a macro
 
  /// argument's expansion into the function-like macro definition.
 
  ///
 
  /// \param StartLoc If non-null and function returns true, it is set to the
 
  /// start location of the macro argument expansion.
 
  ///
 
  /// Such source locations only appear inside of the expansion
 
  /// locations representing where a particular function-like macro was
 
  /// expanded.
 
  bool isMacroArgExpansion(SourceLocation Loc,
 
                           SourceLocation *StartLoc = nullptr) const;
 
 
 
  /// Tests whether the given source location represents the expansion of
 
  /// a macro body.
 
  ///
 
  /// This is equivalent to testing whether the location is part of a macro
 
  /// expansion but not the expansion of an argument to a function-like macro.
 
  bool isMacroBodyExpansion(SourceLocation Loc) const;
 
 
 
  /// Returns true if the given MacroID location points at the beginning
 
  /// of the immediate macro expansion.
 
  ///
 
  /// \param MacroBegin If non-null and function returns true, it is set to the
 
  /// begin location of the immediate macro expansion.
 
  bool isAtStartOfImmediateMacroExpansion(SourceLocation Loc,
 
                                    SourceLocation *MacroBegin = nullptr) const;
 
 
 
  /// Returns true if the given MacroID location points at the character
 
  /// end of the immediate macro expansion.
 
  ///
 
  /// \param MacroEnd If non-null and function returns true, it is set to the
 
  /// character end location of the immediate macro expansion.
 
  bool
 
  isAtEndOfImmediateMacroExpansion(SourceLocation Loc,
 
                                   SourceLocation *MacroEnd = nullptr) const;
 
 
 
  /// Returns true if \p Loc is inside the [\p Start, +\p Length)
 
  /// chunk of the source location address space.
 
  ///
 
  /// If it's true and \p RelativeOffset is non-null, it will be set to the
 
  /// relative offset of \p Loc inside the chunk.
 
  bool
 
  isInSLocAddrSpace(SourceLocation Loc, SourceLocation Start, unsigned Length,
 
                    SourceLocation::UIntTy *RelativeOffset = nullptr) const {
 
    assert(((Start.getOffset() < NextLocalOffset &&
 
               Start.getOffset()+Length <= NextLocalOffset) ||
 
            (Start.getOffset() >= CurrentLoadedOffset &&
 
                Start.getOffset()+Length < MaxLoadedOffset)) &&
 
           "Chunk is not valid SLoc address space");
 
    SourceLocation::UIntTy LocOffs = Loc.getOffset();
 
    SourceLocation::UIntTy BeginOffs = Start.getOffset();
 
    SourceLocation::UIntTy EndOffs = BeginOffs + Length;
 
    if (LocOffs >= BeginOffs && LocOffs < EndOffs) {
 
      if (RelativeOffset)
 
        *RelativeOffset = LocOffs - BeginOffs;
 
      return true;
 
    }
 
 
 
    return false;
 
  }
 
 
 
  /// Return true if both \p LHS and \p RHS are in the local source
 
  /// location address space or the loaded one.
 
  ///
 
  /// If it's true and \p RelativeOffset is non-null, it will be set to the
 
  /// offset of \p RHS relative to \p LHS.
 
  bool isInSameSLocAddrSpace(SourceLocation LHS, SourceLocation RHS,
 
                             SourceLocation::IntTy *RelativeOffset) const {
 
    SourceLocation::UIntTy LHSOffs = LHS.getOffset(), RHSOffs = RHS.getOffset();
 
    bool LHSLoaded = LHSOffs >= CurrentLoadedOffset;
 
    bool RHSLoaded = RHSOffs >= CurrentLoadedOffset;
 
 
 
    if (LHSLoaded == RHSLoaded) {
 
      if (RelativeOffset)
 
        *RelativeOffset = RHSOffs - LHSOffs;
 
      return true;
 
    }
 
 
 
    return false;
 
  }
 
 
 
  //===--------------------------------------------------------------------===//
 
  // Queries about the code at a SourceLocation.
 
  //===--------------------------------------------------------------------===//
 
 
 
  /// Return a pointer to the start of the specified location
 
  /// in the appropriate spelling MemoryBuffer.
 
  ///
 
  /// \param Invalid If non-NULL, will be set \c true if an error occurs.
 
  const char *getCharacterData(SourceLocation SL,
 
                               bool *Invalid = nullptr) const;
 
 
 
  /// Return the column # for the specified file position.
 
  ///
 
  /// This is significantly cheaper to compute than the line number.  This
 
  /// returns zero if the column number isn't known.  This may only be called
 
  /// on a file sloc, so you must choose a spelling or expansion location
 
  /// before calling this method.
 
  unsigned getColumnNumber(FileID FID, unsigned FilePos,
 
                           bool *Invalid = nullptr) const;
 
  unsigned getSpellingColumnNumber(SourceLocation Loc,
 
                                   bool *Invalid = nullptr) const;
 
  unsigned getExpansionColumnNumber(SourceLocation Loc,
 
                                    bool *Invalid = nullptr) const;
 
  unsigned getPresumedColumnNumber(SourceLocation Loc,
 
                                   bool *Invalid = nullptr) const;
 
 
 
  /// Given a SourceLocation, return the spelling line number
 
  /// for the position indicated.
 
  ///
 
  /// This requires building and caching a table of line offsets for the
 
  /// MemoryBuffer, so this is not cheap: use only when about to emit a
 
  /// diagnostic.
 
  unsigned getLineNumber(FileID FID, unsigned FilePos, bool *Invalid = nullptr) const;
 
  unsigned getSpellingLineNumber(SourceLocation Loc, bool *Invalid = nullptr) const;
 
  unsigned getExpansionLineNumber(SourceLocation Loc, bool *Invalid = nullptr) const;
 
  unsigned getPresumedLineNumber(SourceLocation Loc, bool *Invalid = nullptr) const;
 
 
 
  /// Return the filename or buffer identifier of the buffer the
 
  /// location is in.
 
  ///
 
  /// Note that this name does not respect \#line directives.  Use
 
  /// getPresumedLoc for normal clients.
 
  StringRef getBufferName(SourceLocation Loc, bool *Invalid = nullptr) const;
 
 
 
  /// Return the file characteristic of the specified source
 
  /// location, indicating whether this is a normal file, a system
 
  /// header, or an "implicit extern C" system header.
 
  ///
 
  /// This state can be modified with flags on GNU linemarker directives like:
 
  /// \code
 
  ///   # 4 "foo.h" 3
 
  /// \endcode
 
  /// which changes all source locations in the current file after that to be
 
  /// considered to be from a system header.
 
  SrcMgr::CharacteristicKind getFileCharacteristic(SourceLocation Loc) const;
 
 
 
  /// Returns the "presumed" location of a SourceLocation specifies.
 
  ///
 
  /// A "presumed location" can be modified by \#line or GNU line marker
 
  /// directives.  This provides a view on the data that a user should see
 
  /// in diagnostics, for example.
 
  ///
 
  /// Note that a presumed location is always given as the expansion point of
 
  /// an expansion location, not at the spelling location.
 
  ///
 
  /// \returns The presumed location of the specified SourceLocation. If the
 
  /// presumed location cannot be calculated (e.g., because \p Loc is invalid
 
  /// or the file containing \p Loc has changed on disk), returns an invalid
 
  /// presumed location.
 
  PresumedLoc getPresumedLoc(SourceLocation Loc,
 
                             bool UseLineDirectives = true) const;
 
 
 
  /// Returns whether the PresumedLoc for a given SourceLocation is
 
  /// in the main file.
 
  ///
 
  /// This computes the "presumed" location for a SourceLocation, then checks
 
  /// whether it came from a file other than the main file. This is different
 
  /// from isWrittenInMainFile() because it takes line marker directives into
 
  /// account.
 
  bool isInMainFile(SourceLocation Loc) const;
 
 
 
  /// Returns true if the spelling locations for both SourceLocations
 
  /// are part of the same file buffer.
 
  ///
 
  /// This check ignores line marker directives.
 
  bool isWrittenInSameFile(SourceLocation Loc1, SourceLocation Loc2) const {
 
    return getFileID(Loc1) == getFileID(Loc2);
 
  }
 
 
 
  /// Returns true if the spelling location for the given location
 
  /// is in the main file buffer.
 
  ///
 
  /// This check ignores line marker directives.
 
  bool isWrittenInMainFile(SourceLocation Loc) const {
 
    return getFileID(Loc) == getMainFileID();
 
  }
 
 
 
  /// Returns whether \p Loc is located in a <built-in> file.
 
  bool isWrittenInBuiltinFile(SourceLocation Loc) const {
 
    PresumedLoc Presumed = getPresumedLoc(Loc);
 
    if (Presumed.isInvalid())
 
      return false;
 
    StringRef Filename(Presumed.getFilename());
 
    return Filename.equals("<built-in>");
 
  }
 
 
 
  /// Returns whether \p Loc is located in a <command line> file.
 
  bool isWrittenInCommandLineFile(SourceLocation Loc) const {
 
    PresumedLoc Presumed = getPresumedLoc(Loc);
 
    if (Presumed.isInvalid())
 
      return false;
 
    StringRef Filename(Presumed.getFilename());
 
    return Filename.equals("<command line>");
 
  }
 
 
 
  /// Returns whether \p Loc is located in a <scratch space> file.
 
  bool isWrittenInScratchSpace(SourceLocation Loc) const {
 
    PresumedLoc Presumed = getPresumedLoc(Loc);
 
    if (Presumed.isInvalid())
 
      return false;
 
    StringRef Filename(Presumed.getFilename());
 
    return Filename.equals("<scratch space>");
 
  }
 
 
 
  /// Returns if a SourceLocation is in a system header.
 
  bool isInSystemHeader(SourceLocation Loc) const {
 
    if (Loc.isInvalid())
 
      return false;
 
    return isSystem(getFileCharacteristic(Loc));
 
  }
 
 
 
  /// Returns if a SourceLocation is in an "extern C" system header.
 
  bool isInExternCSystemHeader(SourceLocation Loc) const {
 
    return getFileCharacteristic(Loc) == SrcMgr::C_ExternCSystem;
 
  }
 
 
 
  /// Returns whether \p Loc is expanded from a macro in a system header.
 
  bool isInSystemMacro(SourceLocation loc) const {
 
    if (!loc.isMacroID())
 
      return false;
 
 
 
    // This happens when the macro is the result of a paste, in that case
 
    // its spelling is the scratch memory, so we take the parent context.
 
    // There can be several level of token pasting.
 
    if (isWrittenInScratchSpace(getSpellingLoc(loc))) {
 
      do {
 
        loc = getImmediateMacroCallerLoc(loc);
 
      } while (isWrittenInScratchSpace(getSpellingLoc(loc)));
 
      return isInSystemMacro(loc);
 
    }
 
 
 
    return isInSystemHeader(getSpellingLoc(loc));
 
  }
 
 
 
  /// The size of the SLocEntry that \p FID represents.
 
  unsigned getFileIDSize(FileID FID) const;
 
 
 
  /// Given a specific FileID, returns true if \p Loc is inside that
 
  /// FileID chunk and sets relative offset (offset of \p Loc from beginning
 
  /// of FileID) to \p relativeOffset.
 
  bool isInFileID(SourceLocation Loc, FileID FID,
 
                  unsigned *RelativeOffset = nullptr) const {
 
    SourceLocation::UIntTy Offs = Loc.getOffset();
 
    if (isOffsetInFileID(FID, Offs)) {
 
      if (RelativeOffset)
 
        *RelativeOffset = Offs - getSLocEntry(FID).getOffset();
 
      return true;
 
    }
 
 
 
    return false;
 
  }
 
 
 
  //===--------------------------------------------------------------------===//
 
  // Line Table Manipulation Routines
 
  //===--------------------------------------------------------------------===//
 
 
 
  /// Return the uniqued ID for the specified filename.
 
  unsigned getLineTableFilenameID(StringRef Str);
 
 
 
  /// Add a line note to the line table for the FileID and offset
 
  /// specified by Loc.
 
  ///
 
  /// If FilenameID is -1, it is considered to be unspecified.
 
  void AddLineNote(SourceLocation Loc, unsigned LineNo, int FilenameID,
 
                   bool IsFileEntry, bool IsFileExit,
 
                   SrcMgr::CharacteristicKind FileKind);
 
 
 
  /// Determine if the source manager has a line table.
 
  bool hasLineTable() const { return LineTable != nullptr; }
 
 
 
  /// Retrieve the stored line table.
 
  LineTableInfo &getLineTable();
 
 
 
  //===--------------------------------------------------------------------===//
 
  // Queries for performance analysis.
 
  //===--------------------------------------------------------------------===//
 
 
 
  /// Return the total amount of physical memory allocated by the
 
  /// ContentCache allocator.
 
  size_t getContentCacheSize() const {
 
    return ContentCacheAlloc.getTotalMemory();
 
  }
 
 
 
  struct MemoryBufferSizes {
 
    const size_t malloc_bytes;
 
    const size_t mmap_bytes;
 
 
 
    MemoryBufferSizes(size_t malloc_bytes, size_t mmap_bytes)
 
      : malloc_bytes(malloc_bytes), mmap_bytes(mmap_bytes) {}
 
  };
 
 
 
  /// Return the amount of memory used by memory buffers, breaking down
 
  /// by heap-backed versus mmap'ed memory.
 
  MemoryBufferSizes getMemoryBufferSizes() const;
 
 
 
  /// Return the amount of memory used for various side tables and
 
  /// data structures in the SourceManager.
 
  size_t getDataStructureSizes() const;
 
 
 
  //===--------------------------------------------------------------------===//
 
  // Other miscellaneous methods.
 
  //===--------------------------------------------------------------------===//
 
 
 
  /// Get the source location for the given file:line:col triplet.
 
  ///
 
  /// If the source file is included multiple times, the source location will
 
  /// be based upon the first inclusion.
 
  SourceLocation translateFileLineCol(const FileEntry *SourceFile,
 
                                      unsigned Line, unsigned Col) const;
 
 
 
  /// Get the FileID for the given file.
 
  ///
 
  /// If the source file is included multiple times, the FileID will be the
 
  /// first inclusion.
 
  FileID translateFile(const FileEntry *SourceFile) const;
 
  FileID translateFile(FileEntryRef SourceFile) const {
 
    return translateFile(&SourceFile.getFileEntry());
 
  }
 
 
 
  /// Get the source location in \p FID for the given line:col.
 
  /// Returns null location if \p FID is not a file SLocEntry.
 
  SourceLocation translateLineCol(FileID FID,
 
                                  unsigned Line, unsigned Col) const;
 
 
 
  /// If \p Loc points inside a function macro argument, the returned
 
  /// location will be the macro location in which the argument was expanded.
 
  /// If a macro argument is used multiple times, the expanded location will
 
  /// be at the first expansion of the argument.
 
  /// e.g.
 
  ///   MY_MACRO(foo);
 
  ///             ^
 
  /// Passing a file location pointing at 'foo', will yield a macro location
 
  /// where 'foo' was expanded into.
 
  SourceLocation getMacroArgExpandedLocation(SourceLocation Loc) const;
 
 
 
  /// Determines the order of 2 source locations in the translation unit.
 
  ///
 
  /// \returns true if LHS source location comes before RHS, false otherwise.
 
  bool isBeforeInTranslationUnit(SourceLocation LHS, SourceLocation RHS) const;
 
 
 
  /// Determines whether the two decomposed source location is in the
 
  ///        same translation unit. As a byproduct, it also calculates the order
 
  ///        of the source locations in case they are in the same TU.
 
  ///
 
  /// \returns Pair of bools the first component is true if the two locations
 
  ///          are in the same TU. The second bool is true if the first is true
 
  ///          and \p LOffs is before \p ROffs.
 
  std::pair<bool, bool>
 
  isInTheSameTranslationUnit(std::pair<FileID, unsigned> &LOffs,
 
                             std::pair<FileID, unsigned> &ROffs) const;
 
 
 
  /// Determines the order of 2 source locations in the "source location
 
  /// address space".
 
  bool isBeforeInSLocAddrSpace(SourceLocation LHS, SourceLocation RHS) const {
 
    return isBeforeInSLocAddrSpace(LHS, RHS.getOffset());
 
  }
 
 
 
  /// Determines the order of a source location and a source location
 
  /// offset in the "source location address space".
 
  ///
 
  /// Note that we always consider source locations loaded from
 
  bool isBeforeInSLocAddrSpace(SourceLocation LHS,
 
                               SourceLocation::UIntTy RHS) const {
 
    SourceLocation::UIntTy LHSOffset = LHS.getOffset();
 
    bool LHSLoaded = LHSOffset >= CurrentLoadedOffset;
 
    bool RHSLoaded = RHS >= CurrentLoadedOffset;
 
    if (LHSLoaded == RHSLoaded)
 
      return LHSOffset < RHS;
 
 
 
    return LHSLoaded;
 
  }
 
 
 
  /// Return true if the Point is within Start and End.
 
  bool isPointWithin(SourceLocation Location, SourceLocation Start,
 
                     SourceLocation End) const {
 
    return Location == Start || Location == End ||
 
           (isBeforeInTranslationUnit(Start, Location) &&
 
            isBeforeInTranslationUnit(Location, End));
 
  }
 
 
 
  // Iterators over FileInfos.
 
  using fileinfo_iterator =
 
      llvm::DenseMap<const FileEntry*, SrcMgr::ContentCache*>::const_iterator;
 
 
 
  fileinfo_iterator fileinfo_begin() const { return FileInfos.begin(); }
 
  fileinfo_iterator fileinfo_end() const { return FileInfos.end(); }
 
  bool hasFileInfo(const FileEntry *File) const {
 
    return FileInfos.find(File) != FileInfos.end();
 
  }
 
 
 
  /// Print statistics to stderr.
 
  void PrintStats() const;
 
 
 
  void dump() const;
 
 
 
  // Produce notes describing the current source location address space usage.
 
  void noteSLocAddressSpaceUsage(DiagnosticsEngine &Diag,
 
                                 std::optional<unsigned> MaxNotes = 32) const;
 
 
 
  /// Get the number of local SLocEntries we have.
 
  unsigned local_sloc_entry_size() const { return LocalSLocEntryTable.size(); }
 
 
 
  /// Get a local SLocEntry. This is exposed for indexing.
 
  const SrcMgr::SLocEntry &getLocalSLocEntry(unsigned Index) const {
 
    assert(Index < LocalSLocEntryTable.size() && "Invalid index");
 
    return LocalSLocEntryTable[Index];
 
  }
 
 
 
  /// Get the number of loaded SLocEntries we have.
 
  unsigned loaded_sloc_entry_size() const { return LoadedSLocEntryTable.size();}
 
 
 
  /// Get a loaded SLocEntry. This is exposed for indexing.
 
  const SrcMgr::SLocEntry &getLoadedSLocEntry(unsigned Index,
 
                                              bool *Invalid = nullptr) const {
 
    assert(Index < LoadedSLocEntryTable.size() && "Invalid index");
 
    if (SLocEntryLoaded[Index])
 
      return LoadedSLocEntryTable[Index];
 
    return loadSLocEntry(Index, Invalid);
 
  }
 
 
 
  const SrcMgr::SLocEntry &getSLocEntry(FileID FID,
 
                                        bool *Invalid = nullptr) const {
 
    if (FID.ID == 0 || FID.ID == -1) {
 
      if (Invalid) *Invalid = true;
 
      return LocalSLocEntryTable[0];
 
    }
 
    return getSLocEntryByID(FID.ID, Invalid);
 
  }
 
 
 
  SourceLocation::UIntTy getNextLocalOffset() const { return NextLocalOffset; }
 
 
 
  void setExternalSLocEntrySource(ExternalSLocEntrySource *Source) {
 
    assert(LoadedSLocEntryTable.empty() &&
 
           "Invalidating existing loaded entries");
 
    ExternalSLocEntries = Source;
 
  }
 
 
 
  /// Allocate a number of loaded SLocEntries, which will be actually
 
  /// loaded on demand from the external source.
 
  ///
 
  /// NumSLocEntries will be allocated, which occupy a total of TotalSize space
 
  /// in the global source view. The lowest ID and the base offset of the
 
  /// entries will be returned.
 
  std::pair<int, SourceLocation::UIntTy>
 
  AllocateLoadedSLocEntries(unsigned NumSLocEntries,
 
                            SourceLocation::UIntTy TotalSize);
 
 
 
  /// Returns true if \p Loc came from a PCH/Module.
 
  bool isLoadedSourceLocation(SourceLocation Loc) const {
 
    return isLoadedOffset(Loc.getOffset());
 
  }
 
 
 
  /// Returns true if \p Loc did not come from a PCH/Module.
 
  bool isLocalSourceLocation(SourceLocation Loc) const {
 
    return isLocalOffset(Loc.getOffset());
 
  }
 
 
 
  /// Returns true if \p FID came from a PCH/Module.
 
  bool isLoadedFileID(FileID FID) const {
 
    assert(FID.ID != -1 && "Using FileID sentinel value");
 
    return FID.ID < 0;
 
  }
 
 
 
  /// Returns true if \p FID did not come from a PCH/Module.
 
  bool isLocalFileID(FileID FID) const {
 
    return !isLoadedFileID(FID);
 
  }
 
 
 
  /// Gets the location of the immediate macro caller, one level up the stack
 
  /// toward the initial macro typed into the source.
 
  SourceLocation getImmediateMacroCallerLoc(SourceLocation Loc) const {
 
    if (!Loc.isMacroID()) return Loc;
 
 
 
    // When we have the location of (part of) an expanded parameter, its
 
    // spelling location points to the argument as expanded in the macro call,
 
    // and therefore is used to locate the macro caller.
 
    if (isMacroArgExpansion(Loc))
 
      return getImmediateSpellingLoc(Loc);
 
 
 
    // Otherwise, the caller of the macro is located where this macro is
 
    // expanded (while the spelling is part of the macro definition).
 
    return getImmediateExpansionRange(Loc).getBegin();
 
  }
 
 
 
  /// \return Location of the top-level macro caller.
 
  SourceLocation getTopMacroCallerLoc(SourceLocation Loc) const;
 
 
 
private:
 
  friend class ASTReader;
 
  friend class ASTWriter;
 
 
 
  llvm::MemoryBufferRef getFakeBufferForRecovery() const;
 
  SrcMgr::ContentCache &getFakeContentCacheForRecovery() const;
 
 
 
  const SrcMgr::SLocEntry &loadSLocEntry(unsigned Index, bool *Invalid) const;
 
 
 
  const SrcMgr::SLocEntry *getSLocEntryOrNull(FileID FID) const {
 
    bool Invalid = false;
 
    const SrcMgr::SLocEntry &Entry = getSLocEntry(FID, &Invalid);
 
    return Invalid ? nullptr : &Entry;
 
  }
 
 
 
  const SrcMgr::SLocEntry *getSLocEntryForFile(FileID FID) const {
 
    if (auto *Entry = getSLocEntryOrNull(FID))
 
      if (Entry->isFile())
 
        return Entry;
 
    return nullptr;
 
  }
 
 
 
  /// Get the entry with the given unwrapped FileID.
 
  /// Invalid will not be modified for Local IDs.
 
  const SrcMgr::SLocEntry &getSLocEntryByID(int ID,
 
                                            bool *Invalid = nullptr) const {
 
    assert(ID != -1 && "Using FileID sentinel value");
 
    if (ID < 0)
 
      return getLoadedSLocEntryByID(ID, Invalid);
 
    return getLocalSLocEntry(static_cast<unsigned>(ID));
 
  }
 
 
 
  const SrcMgr::SLocEntry &
 
  getLoadedSLocEntryByID(int ID, bool *Invalid = nullptr) const {
 
    return getLoadedSLocEntry(static_cast<unsigned>(-ID - 2), Invalid);
 
  }
 
 
 
  FileID getFileID(SourceLocation::UIntTy SLocOffset) const {
 
    // If our one-entry cache covers this offset, just return it.
 
    if (isOffsetInFileID(LastFileIDLookup, SLocOffset))
 
      return LastFileIDLookup;
 
 
 
    return getFileIDSlow(SLocOffset);
 
  }
 
 
 
  bool isLocalOffset(SourceLocation::UIntTy SLocOffset) const {
 
    return SLocOffset < CurrentLoadedOffset;
 
  }
 
 
 
  bool isLoadedOffset(SourceLocation::UIntTy SLocOffset) const {
 
    return SLocOffset >= CurrentLoadedOffset;
 
  }
 
 
 
  /// Implements the common elements of storing an expansion info struct into
 
  /// the SLocEntry table and producing a source location that refers to it.
 
  SourceLocation
 
  createExpansionLocImpl(const SrcMgr::ExpansionInfo &Expansion,
 
                         unsigned Length, int LoadedID = 0,
 
                         SourceLocation::UIntTy LoadedOffset = 0);
 
 
 
  /// Return true if the specified FileID contains the
 
  /// specified SourceLocation offset.  This is a very hot method.
 
  inline bool isOffsetInFileID(FileID FID,
 
                               SourceLocation::UIntTy SLocOffset) const {
 
    const SrcMgr::SLocEntry &Entry = getSLocEntry(FID);
 
    // If the entry is after the offset, it can't contain it.
 
    if (SLocOffset < Entry.getOffset()) return false;
 
 
 
    // If this is the very last entry then it does.
 
    if (FID.ID == -2)
 
      return true;
 
 
 
    // If it is the last local entry, then it does if the location is local.
 
    if (FID.ID+1 == static_cast<int>(LocalSLocEntryTable.size()))
 
      return SLocOffset < NextLocalOffset;
 
 
 
    // Otherwise, the entry after it has to not include it. This works for both
 
    // local and loaded entries.
 
    return SLocOffset < getSLocEntryByID(FID.ID+1).getOffset();
 
  }
 
 
 
  /// Returns the previous in-order FileID or an invalid FileID if there
 
  /// is no previous one.
 
  FileID getPreviousFileID(FileID FID) const;
 
 
 
  /// Returns the next in-order FileID or an invalid FileID if there is
 
  /// no next one.
 
  FileID getNextFileID(FileID FID) const;
 
 
 
  /// Create a new fileID for the specified ContentCache and
 
  /// include position.
 
  ///
 
  /// This works regardless of whether the ContentCache corresponds to a
 
  /// file or some other input source.
 
  FileID createFileIDImpl(SrcMgr::ContentCache &File, StringRef Filename,
 
                          SourceLocation IncludePos,
 
                          SrcMgr::CharacteristicKind DirCharacter, int LoadedID,
 
                          SourceLocation::UIntTy LoadedOffset);
 
 
 
  SrcMgr::ContentCache &getOrCreateContentCache(FileEntryRef SourceFile,
 
                                                bool isSystemFile = false);
 
 
 
  /// Create a new ContentCache for the specified  memory buffer.
 
  SrcMgr::ContentCache &
 
  createMemBufferContentCache(std::unique_ptr<llvm::MemoryBuffer> Buf);
 
 
 
  FileID getFileIDSlow(SourceLocation::UIntTy SLocOffset) const;
 
  FileID getFileIDLocal(SourceLocation::UIntTy SLocOffset) const;
 
  FileID getFileIDLoaded(SourceLocation::UIntTy SLocOffset) const;
 
 
 
  SourceLocation getExpansionLocSlowCase(SourceLocation Loc) const;
 
  SourceLocation getSpellingLocSlowCase(SourceLocation Loc) const;
 
  SourceLocation getFileLocSlowCase(SourceLocation Loc) const;
 
 
 
  std::pair<FileID, unsigned>
 
  getDecomposedExpansionLocSlowCase(const SrcMgr::SLocEntry *E) const;
 
  std::pair<FileID, unsigned>
 
  getDecomposedSpellingLocSlowCase(const SrcMgr::SLocEntry *E,
 
                                   unsigned Offset) const;
 
  void computeMacroArgsCache(MacroArgsMap &MacroArgsCache, FileID FID) const;
 
  void associateFileChunkWithMacroArgExp(MacroArgsMap &MacroArgsCache,
 
                                         FileID FID,
 
                                         SourceLocation SpellLoc,
 
                                         SourceLocation ExpansionLoc,
 
                                         unsigned ExpansionLength) const;
 
};
 
 
 
/// Comparison function object.
 
template<typename T>
 
class BeforeThanCompare;
 
 
 
/// Compare two source locations.
 
template<>
 
class BeforeThanCompare<SourceLocation> {
 
  SourceManager &SM;
 
 
 
public:
 
  explicit BeforeThanCompare(SourceManager &SM) : SM(SM) {}
 
 
 
  bool operator()(SourceLocation LHS, SourceLocation RHS) const {
 
    return SM.isBeforeInTranslationUnit(LHS, RHS);
 
  }
 
};
 
 
 
/// Compare two non-overlapping source ranges.
 
template<>
 
class BeforeThanCompare<SourceRange> {
 
  SourceManager &SM;
 
 
 
public:
 
  explicit BeforeThanCompare(SourceManager &SM) : SM(SM) {}
 
 
 
  bool operator()(SourceRange LHS, SourceRange RHS) const {
 
    return SM.isBeforeInTranslationUnit(LHS.getBegin(), RHS.getBegin());
 
  }
 
};
 
 
 
/// SourceManager and necessary dependencies (e.g. VFS, FileManager) for a
 
/// single in-memorty file.
 
class SourceManagerForFile {
 
public:
 
  /// Creates SourceManager and necessary dependencies (e.g. VFS, FileManager).
 
  /// The main file in the SourceManager will be \p FileName with \p Content.
 
  SourceManagerForFile(StringRef FileName, StringRef Content);
 
 
 
  SourceManager &get() {
 
    assert(SourceMgr);
 
    return *SourceMgr;
 
  }
 
 
 
private:
 
  // The order of these fields are important - they should be in the same order
 
  // as they are created in `createSourceManagerForFile` so that they can be
 
  // deleted in the reverse order as they are created.
 
  std::unique_ptr<FileManager> FileMgr;
 
  std::unique_ptr<DiagnosticsEngine> Diagnostics;
 
  std::unique_ptr<SourceManager> SourceMgr;
 
};
 
 
 
} // namespace clang
 
 
 
#endif // LLVM_CLANG_BASIC_SOURCEMANAGER_H