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//===- SourceMgr.h - Manager for Source Buffers & Diagnostics ---*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file declares the SMDiagnostic and SourceMgr classes. This
// provides a simple substrate for diagnostics, #include handling, and other low
// level things for simple parsers.
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SMLoc.h"
#include <algorithm>
#include <cassert>
#include <memory>
#include <string>
#include <utility>
#include <vector>
namespace llvm {
class raw_ostream;
class SMDiagnostic;
class SMFixIt;
/// This owns the files read by a parser, handles include stacks,
/// and handles diagnostic wrangling.
class SourceMgr {
enum DiagKind {
/// Clients that want to handle their own diagnostics in a custom way can
/// register a function pointer+context as a diagnostic handler.
/// It gets called each time PrintMessage is invoked.
using DiagHandlerTy = void (*)(const SMDiagnostic &, void *Context);
struct SrcBuffer {
/// The memory buffer for the file.
std::unique_ptr<MemoryBuffer> Buffer;
/// Helper type for OffsetCache below: since we're storing many offsets
/// into relatively small files (often smaller than 2^8 or 2^16 bytes),
/// we select the offset vector element type dynamically based on the
/// size of Buffer.
using VariableSizeOffsets = PointerUnion4<std::vector<uint8_t> *,
std::vector<uint16_t> *,
std::vector<uint32_t> *,
std::vector<uint64_t> *>;
/// Vector of offsets into Buffer at which there are line-endings
/// (lazily populated). Once populated, the '\n' that marks the end of
/// line number N from [1..] is at Buffer[OffsetCache[N-1]]. Since
/// these offsets are in sorted (ascending) order, they can be
/// binary-searched for the first one after any given offset (eg. an
/// offset corresponding to a particular SMLoc).
mutable VariableSizeOffsets OffsetCache;
/// Populate \c OffsetCache and look up a given \p Ptr in it, assuming
/// it points somewhere into \c Buffer. The static type parameter \p T
/// must be an unsigned integer type from uint{8,16,32,64}_t large
/// enough to store offsets inside \c Buffer.
template<typename T>
unsigned getLineNumber(const char *Ptr) const;
/// This is the location of the parent include, or null if at the top level.
SMLoc IncludeLoc;
SrcBuffer() = default;
SrcBuffer(SrcBuffer &&);
SrcBuffer(const SrcBuffer &) = delete;
SrcBuffer &operator=(const SrcBuffer &) = delete;
/// This is all of the buffers that we are reading from.
std::vector<SrcBuffer> Buffers;
// This is the list of directories we should search for include files in.
std::vector<std::string> IncludeDirectories;
DiagHandlerTy DiagHandler = nullptr;
void *DiagContext = nullptr;
bool isValidBufferID(unsigned i) const { return i && i <= Buffers.size(); }
SourceMgr() = default;
SourceMgr(const SourceMgr &) = delete;
SourceMgr &operator=(const SourceMgr &) = delete;
~SourceMgr() = default;
void setIncludeDirs(const std::vector<std::string> &Dirs) {
IncludeDirectories = Dirs;
/// Specify a diagnostic handler to be invoked every time PrintMessage is
/// called. \p Ctx is passed into the handler when it is invoked.
void setDiagHandler(DiagHandlerTy DH, void *Ctx = nullptr) {
DiagHandler = DH;
DiagContext = Ctx;
DiagHandlerTy getDiagHandler() const { return DiagHandler; }
void *getDiagContext() const { return DiagContext; }
const SrcBuffer &getBufferInfo(unsigned i) const {
return Buffers[i - 1];
const MemoryBuffer *getMemoryBuffer(unsigned i) const {
return Buffers[i - 1].Buffer.get();
unsigned getNumBuffers() const {
return Buffers.size();
unsigned getMainFileID() const {
return 1;
SMLoc getParentIncludeLoc(unsigned i) const {
return Buffers[i - 1].IncludeLoc;
/// Add a new source buffer to this source manager. This takes ownership of
/// the memory buffer.
unsigned AddNewSourceBuffer(std::unique_ptr<MemoryBuffer> F,
SMLoc IncludeLoc) {
SrcBuffer NB;
NB.Buffer = std::move(F);
NB.IncludeLoc = IncludeLoc;
return Buffers.size();
/// Search for a file with the specified name in the current directory or in
/// one of the IncludeDirs.
/// If no file is found, this returns 0, otherwise it returns the buffer ID
/// of the stacked file. The full path to the included file can be found in
/// \p IncludedFile.
unsigned AddIncludeFile(const std::string &Filename, SMLoc IncludeLoc,
std::string &IncludedFile);
/// Return the ID of the buffer containing the specified location.
/// 0 is returned if the buffer is not found.
unsigned FindBufferContainingLoc(SMLoc Loc) const;
/// Find the line number for the specified location in the specified file.
/// This is not a fast method.
unsigned FindLineNumber(SMLoc Loc, unsigned BufferID = 0) const {
return getLineAndColumn(Loc, BufferID).first;
/// Find the line and column number for the specified location in the
/// specified file. This is not a fast method.
std::pair<unsigned, unsigned> getLineAndColumn(SMLoc Loc,
unsigned BufferID = 0) const;
/// Emit a message about the specified location with the specified string.
/// \param ShowColors Display colored messages if output is a terminal and
/// the default error handler is used.
void PrintMessage(raw_ostream &OS, SMLoc Loc, DiagKind Kind,
const Twine &Msg,
ArrayRef<SMRange> Ranges = None,
ArrayRef<SMFixIt> FixIts = None,
bool ShowColors = true) const;
/// Emits a diagnostic to llvm::errs().
void PrintMessage(SMLoc Loc, DiagKind Kind, const Twine &Msg,
ArrayRef<SMRange> Ranges = None,
ArrayRef<SMFixIt> FixIts = None,
bool ShowColors = true) const;
/// Emits a manually-constructed diagnostic to the given output stream.
/// \param ShowColors Display colored messages if output is a terminal and
/// the default error handler is used.
void PrintMessage(raw_ostream &OS, const SMDiagnostic &Diagnostic,
bool ShowColors = true) const;
/// Return an SMDiagnostic at the specified location with the specified
/// string.
/// \param Msg If non-null, the kind of message (e.g., "error") which is
/// prefixed to the message.
SMDiagnostic GetMessage(SMLoc Loc, DiagKind Kind, const Twine &Msg,
ArrayRef<SMRange> Ranges = None,
ArrayRef<SMFixIt> FixIts = None) const;
/// Prints the names of included files and the line of the file they were
/// included from. A diagnostic handler can use this before printing its
/// custom formatted message.
/// \param IncludeLoc The location of the include.
/// \param OS the raw_ostream to print on.
void PrintIncludeStack(SMLoc IncludeLoc, raw_ostream &OS) const;
/// Represents a single fixit, a replacement of one range of text with another.
class SMFixIt {
SMRange Range;
std::string Text;
// FIXME: Twine.str() is not very efficient.
SMFixIt(SMLoc Loc, const Twine &Insertion)
: Range(Loc, Loc), Text(Insertion.str()) {
// FIXME: Twine.str() is not very efficient.
SMFixIt(SMRange R, const Twine &Replacement)
: Range(R), Text(Replacement.str()) {
StringRef getText() const { return Text; }
SMRange getRange() const { return Range; }
bool operator<(const SMFixIt &Other) const {
if (Range.Start.getPointer() != Other.Range.Start.getPointer())
return Range.Start.getPointer() < Other.Range.Start.getPointer();
if (Range.End.getPointer() != Other.Range.End.getPointer())
return Range.End.getPointer() < Other.Range.End.getPointer();
return Text < Other.Text;
/// Instances of this class encapsulate one diagnostic report, allowing
/// printing to a raw_ostream as a caret diagnostic.
class SMDiagnostic {
const SourceMgr *SM = nullptr;
SMLoc Loc;
std::string Filename;
int LineNo = 0;
int ColumnNo = 0;
SourceMgr::DiagKind Kind = SourceMgr::DK_Error;
std::string Message, LineContents;
std::vector<std::pair<unsigned, unsigned>> Ranges;
SmallVector<SMFixIt, 4> FixIts;
// Null diagnostic.
SMDiagnostic() = default;
// Diagnostic with no location (e.g. file not found, command line arg error).
SMDiagnostic(StringRef filename, SourceMgr::DiagKind Knd, StringRef Msg)
: Filename(filename), LineNo(-1), ColumnNo(-1), Kind(Knd), Message(Msg) {}
// Diagnostic with a location.
SMDiagnostic(const SourceMgr &sm, SMLoc L, StringRef FN,
int Line, int Col, SourceMgr::DiagKind Kind,
StringRef Msg, StringRef LineStr,
ArrayRef<std::pair<unsigned,unsigned>> Ranges,
ArrayRef<SMFixIt> FixIts = None);
const SourceMgr *getSourceMgr() const { return SM; }
SMLoc getLoc() const { return Loc; }
StringRef getFilename() const { return Filename; }
int getLineNo() const { return LineNo; }
int getColumnNo() const { return ColumnNo; }
SourceMgr::DiagKind getKind() const { return Kind; }
StringRef getMessage() const { return Message; }
StringRef getLineContents() const { return LineContents; }
ArrayRef<std::pair<unsigned, unsigned>> getRanges() const { return Ranges; }
void addFixIt(const SMFixIt &Hint) {
ArrayRef<SMFixIt> getFixIts() const {
return FixIts;
void print(const char *ProgName, raw_ostream &S, bool ShowColors = true,
bool ShowKindLabel = true) const;
} // end namespace llvm