//===-- CXLoadedDiagnostic.cpp - Handling of persisent diags ----*- 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

//

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

//

// Implements handling of persisent diagnostics.

//

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

#include "CXLoadedDiagnostic.h"

#include "CXString.h"

#include "clang/Basic/Diagnostic.h"

#include "clang/Basic/FileManager.h"

#include "clang/Basic/LLVM.h"

#include "clang/Frontend/SerializedDiagnosticReader.h"

#include "clang/Frontend/SerializedDiagnostics.h"

#include "llvm/ADT/STLExtras.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/ADT/Twine.h"

#include "llvm/Bitstream/BitstreamReader.h"

#include "llvm/Support/ErrorHandling.h"

using namespace clang;

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

// Extend CXDiagnosticSetImpl which contains strings for diagnostics.

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

typedef llvm::DenseMap<unsigned, const char *> Strings;

namespace {

class CXLoadedDiagnosticSetImpl : public CXDiagnosticSetImpl {

public:

  CXLoadedDiagnosticSetImpl() : CXDiagnosticSetImpl(true), FakeFiles(FO) {}

  ~CXLoadedDiagnosticSetImpl() override {}

  llvm::BumpPtrAllocator Alloc;

  Strings Categories;

  Strings WarningFlags;

  Strings FileNames;

  FileSystemOptions FO;

  FileManager FakeFiles;

  llvm::DenseMap<unsigned, const FileEntry *> Files;

  /// Copy the string into our own allocator.

  const char *copyString(StringRef Blob) {

    char *mem = Alloc.Allocate<char>(Blob.size() + 1);

    memcpy(mem, Blob.data(), Blob.size());

    mem[Blob.size()] = '\0';

    return mem;

  }

};

} // end anonymous namespace

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

// Cleanup.

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

CXLoadedDiagnostic::~CXLoadedDiagnostic() {}

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

// Public CXLoadedDiagnostic methods.

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

CXDiagnosticSeverity CXLoadedDiagnostic::getSeverity() const {

  // FIXME: Fail more softly if the diagnostic level is unknown?

  auto severityAsLevel = static_cast<serialized_diags::Level>(severity);

  assert(severity == static_cast<unsigned>(severityAsLevel) &&

         "unknown serialized diagnostic level");

  switch (severityAsLevel) {

#define CASE(X) case serialized_diags::X: return CXDiagnostic_##X;

  CASE(Ignored)

  CASE(Note)

  CASE(Warning)

  CASE(Error)

  CASE(Fatal)

#undef CASE

  // The 'Remark' level isn't represented in the stable API.

  case serialized_diags::Remark: return CXDiagnostic_Warning;

  }

  llvm_unreachable("Invalid diagnostic level");

}

static CXSourceLocation makeLocation(const CXLoadedDiagnostic::Location *DLoc) {

  // The lowest bit of ptr_data[0] is always set to 1 to indicate this

  // is a persistent diagnostic.

  uintptr_t V = (uintptr_t) DLoc;

  V |= 0x1;

  CXSourceLocation Loc = { {  (void*) V, nullptr }, 0 };

  return Loc;

}  

CXSourceLocation CXLoadedDiagnostic::getLocation() const {

  // The lowest bit of ptr_data[0] is always set to 1 to indicate this

  // is a persistent diagnostic.

  return makeLocation(&DiagLoc);

}

CXString CXLoadedDiagnostic::getSpelling() const {

  return cxstring::createRef(Spelling);

}

CXString CXLoadedDiagnostic::getDiagnosticOption(CXString *Disable) const {

  if (DiagOption.empty())

    return cxstring::createEmpty();

  // FIXME: possibly refactor with logic in CXStoredDiagnostic.

  if (Disable)

    *Disable = cxstring::createDup((Twine("-Wno-") + DiagOption).str());

  return cxstring::createDup((Twine("-W") + DiagOption).str());

}

unsigned CXLoadedDiagnostic::getCategory() const {

  return category;

}

CXString CXLoadedDiagnostic::getCategoryText() const {

  return cxstring::createDup(CategoryText);

}

unsigned CXLoadedDiagnostic::getNumRanges() const {

  return Ranges.size();

}

CXSourceRange CXLoadedDiagnostic::getRange(unsigned Range) const {

  assert(Range < Ranges.size());

  return Ranges[Range];

}

unsigned CXLoadedDiagnostic::getNumFixIts() const {

  return FixIts.size();

}

CXString CXLoadedDiagnostic::getFixIt(unsigned FixIt,

                                      CXSourceRange *ReplacementRange) const {

  assert(FixIt < FixIts.size());

  if (ReplacementRange)

    *ReplacementRange = FixIts[FixIt].first;

  return cxstring::createRef(FixIts[FixIt].second);

}

void CXLoadedDiagnostic::decodeLocation(CXSourceLocation location,

                                        CXFile *file,

                                        unsigned int *line,

                                        unsigned int *column,

                                        unsigned int *offset) {

  // CXSourceLocation consists of the following fields:

  //

  //   void *ptr_data[2];

  //   unsigned int_data;

  //

  // The lowest bit of ptr_data[0] is always set to 1 to indicate this

  // is a persistent diagnostic.

  //

  // For now, do the unoptimized approach and store the data in a side

  // data structure.  We can optimize this case later.

  uintptr_t V = (uintptr_t) location.ptr_data[0];

  assert((V & 0x1) == 1);

  V &= ~(uintptr_t)1;

  const Location &Loc = *((Location*)V);

  if (file)

    *file = Loc.file;  

  if (line)

    *line = Loc.line;

  if (column)

    *column = Loc.column;

  if (offset)

    *offset = Loc.offset;

}

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

// Deserialize diagnostics.

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

namespace {

class DiagLoader : serialized_diags::SerializedDiagnosticReader {

  enum CXLoadDiag_Error *error;

  CXString *errorString;

  std::unique_ptr<CXLoadedDiagnosticSetImpl> TopDiags;

  SmallVector<std::unique_ptr<CXLoadedDiagnostic>, 8> CurrentDiags;

  std::error_code reportBad(enum CXLoadDiag_Error code, llvm::StringRef err) {

    if (error)

      *error = code;

    if (errorString)

      *errorString = cxstring::createDup(err);

    return serialized_diags::SDError::HandlerFailed;

  }

  std::error_code reportInvalidFile(llvm::StringRef err) {

    return reportBad(CXLoadDiag_InvalidFile, err);

  }

  std::error_code readRange(const serialized_diags::Location &SDStart,

                            const serialized_diags::Location &SDEnd,

                            CXSourceRange &SR);

  std::error_code readLocation(const serialized_diags::Location &SDLoc,

                               CXLoadedDiagnostic::Location &LoadedLoc);

protected:

  std::error_code visitStartOfDiagnostic() override;

  std::error_code visitEndOfDiagnostic() override;

  std::error_code visitCategoryRecord(unsigned ID, StringRef Name) override;

  std::error_code visitDiagFlagRecord(unsigned ID, StringRef Name) override;

  std::error_code visitDiagnosticRecord(

      unsigned Severity, const serialized_diags::Location &Location,

      unsigned Category, unsigned Flag, StringRef Message) override;

  std::error_code visitFilenameRecord(unsigned ID, unsigned Size,

                                      unsigned Timestamp,

                                      StringRef Name) override;

  std::error_code visitFixitRecord(const serialized_diags::Location &Start,

                                   const serialized_diags::Location &End,

                                   StringRef CodeToInsert) override;

  std::error_code

  visitSourceRangeRecord(const serialized_diags::Location &Start,

                         const serialized_diags::Location &End) override;

public:

  DiagLoader(enum CXLoadDiag_Error *e, CXString *es)

      : SerializedDiagnosticReader(), error(e), errorString(es) {

    if (error)

      *error = CXLoadDiag_None;

    if (errorString)

      *errorString = cxstring::createEmpty();

  }

  CXDiagnosticSet load(const char *file);

};

} // end anonymous namespace

CXDiagnosticSet DiagLoader::load(const char *file) {

  TopDiags = std::make_unique<CXLoadedDiagnosticSetImpl>();

  std::error_code EC = readDiagnostics(file);

  if (EC) {

    switch (EC.value()) {

    case static_cast<int>(serialized_diags::SDError::HandlerFailed):

      // We've already reported the problem.

      break;

    case static_cast<int>(serialized_diags::SDError::CouldNotLoad):

      reportBad(CXLoadDiag_CannotLoad, EC.message());

      break;

    default:

      reportInvalidFile(EC.message());

      break;

    }

    return nullptr;

  }

  return (CXDiagnosticSet)TopDiags.release();

}

std::error_code

DiagLoader::readLocation(const serialized_diags::Location &SDLoc,

                         CXLoadedDiagnostic::Location &LoadedLoc) {

  unsigned FileID = SDLoc.FileID;

  if (FileID == 0)

    LoadedLoc.file = nullptr;

  else {

    LoadedLoc.file = const_cast<FileEntry *>(TopDiags->Files[FileID]);

    if (!LoadedLoc.file)

      return reportInvalidFile("Corrupted file entry in source location");

  }

  LoadedLoc.line = SDLoc.Line;

  LoadedLoc.column = SDLoc.Col;

  LoadedLoc.offset = SDLoc.Offset;

  return std::error_code();

}

std::error_code

DiagLoader::readRange(const serialized_diags::Location &SDStart,

                      const serialized_diags::Location &SDEnd,

                      CXSourceRange &SR) {

  CXLoadedDiagnostic::Location *Start, *End;

  Start = TopDiags->Alloc.Allocate<CXLoadedDiagnostic::Location>();

  End = TopDiags->Alloc.Allocate<CXLoadedDiagnostic::Location>();

  std::error_code EC;

  if ((EC = readLocation(SDStart, *Start)))

    return EC;

  if ((EC = readLocation(SDEnd, *End)))

    return EC;

  CXSourceLocation startLoc = makeLocation(Start);

  CXSourceLocation endLoc = makeLocation(End);

  SR = clang_getRange(startLoc, endLoc);

  return std::error_code();

}

std::error_code DiagLoader::visitStartOfDiagnostic() {

  CurrentDiags.push_back(std::make_unique<CXLoadedDiagnostic>());

  return std::error_code();

}

std::error_code DiagLoader::visitEndOfDiagnostic() {

  auto D = CurrentDiags.pop_back_val();

  if (CurrentDiags.empty())

    TopDiags->appendDiagnostic(std::move(D));

  else

    CurrentDiags.back()->getChildDiagnostics().appendDiagnostic(std::move(D));

  return std::error_code();

}

std::error_code DiagLoader::visitCategoryRecord(unsigned ID, StringRef Name) {

  // FIXME: Why do we care about long strings?

  if (Name.size() > 65536)

    return reportInvalidFile("Out-of-bounds string in category");

  TopDiags->Categories[ID] = TopDiags->copyString(Name);

  return std::error_code();

}

std::error_code DiagLoader::visitDiagFlagRecord(unsigned ID, StringRef Name) {

  // FIXME: Why do we care about long strings?

  if (Name.size() > 65536)

    return reportInvalidFile("Out-of-bounds string in warning flag");

  TopDiags->WarningFlags[ID] = TopDiags->copyString(Name);

  return std::error_code();

}

std::error_code DiagLoader::visitFilenameRecord(unsigned ID, unsigned Size,

                                                unsigned Timestamp,

                                                StringRef Name) {

  // FIXME: Why do we care about long strings?

  if (Name.size() > 65536)

    return reportInvalidFile("Out-of-bounds string in filename");

  TopDiags->FileNames[ID] = TopDiags->copyString(Name);

  TopDiags->Files[ID] =

      TopDiags->FakeFiles.getVirtualFile(Name, Size, Timestamp);

  return std::error_code();

}

std::error_code

DiagLoader::visitSourceRangeRecord(const serialized_diags::Location &Start,

                                   const serialized_diags::Location &End) {

  CXSourceRange SR;

  if (std::error_code EC = readRange(Start, End, SR))

    return EC;

  CurrentDiags.back()->Ranges.push_back(SR);

  return std::error_code();

}

std::error_code

DiagLoader::visitFixitRecord(const serialized_diags::Location &Start,

                             const serialized_diags::Location &End,

                             StringRef CodeToInsert) {

  CXSourceRange SR;

  if (std::error_code EC = readRange(Start, End, SR))

    return EC;

  // FIXME: Why do we care about long strings?

  if (CodeToInsert.size() > 65536)

    return reportInvalidFile("Out-of-bounds string in FIXIT");

  CurrentDiags.back()->FixIts.push_back(

      std::make_pair(SR, TopDiags->copyString(CodeToInsert)));

  return std::error_code();

}

std::error_code DiagLoader::visitDiagnosticRecord(

    unsigned Severity, const serialized_diags::Location &Location,

    unsigned Category, unsigned Flag, StringRef Message) {

  CXLoadedDiagnostic &D = *CurrentDiags.back();

  D.severity = Severity;

  if (std::error_code EC = readLocation(Location, D.DiagLoc))

    return EC;

  D.category = Category;

  D.DiagOption = Flag ? 
TopDiags->WarningFlags[Flag]19
 : "";

  D.CategoryText = Category ? TopDiags->Categories[Category] : 
""25
;

  D.Spelling = TopDiags->copyString(Message);

  return std::error_code();

}

CXDiagnosticSet clang_loadDiagnostics(const char *file,

                                      enum CXLoadDiag_Error *error,

                                      CXString *errorString) {

  DiagLoader L(error, errorString);

  return L.load(file);

}