Add the clang library to the repo (with some of my changes, too).

1 files changed, 697 insertions, 0 deletions

diff --git a/clang/lib/Basic/DiagnosticIDs.cpp b/clang/lib/Basic/DiagnosticIDs.cpp
new file mode 100644
index 0000000..8c33a96
--- /dev/null
+++ b/clang/lib/Basic/DiagnosticIDs.cpp
@@ -0,0 +1,697 @@
+//===--- DiagnosticIDs.cpp - Diagnostic IDs Handling ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the Diagnostic IDs-related interfaces.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/DiagnosticIDs.h"
+#include "clang/Basic/AllDiagnostics.h"
+#include "clang/Basic/DiagnosticCategories.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/ErrorHandling.h"
+
+#include <map>
+using namespace clang;
+
+//===----------------------------------------------------------------------===//
+// Builtin Diagnostic information
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+// Diagnostic classes.
+enum {
+  CLASS_NOTE       = 0x01,
+  CLASS_WARNING    = 0x02,
+  CLASS_EXTENSION  = 0x03,
+  CLASS_ERROR      = 0x04
+};
+
+struct StaticDiagInfoRec {
+  unsigned short DiagID;
+  unsigned Mapping : 3;
+  unsigned Class : 3;
+  unsigned SFINAE : 1;
+  unsigned AccessControl : 1;
+  unsigned WarnNoWerror : 1;
+  unsigned WarnShowInSystemHeader : 1;
+  unsigned Category : 5;
+
+  uint16_t OptionGroupIndex;
+
+  uint16_t DescriptionLen;
+  const char *DescriptionStr;
+
+  unsigned getOptionGroupIndex() const {
+    return OptionGroupIndex;
+  }
+
+  StringRef getDescription() const {
+    return StringRef(DescriptionStr, DescriptionLen);
+  }
+
+  bool operator<(const StaticDiagInfoRec &RHS) const {
+    return DiagID < RHS.DiagID;
+  }
+};
+
+} // namespace anonymous
+
+static const StaticDiagInfoRec StaticDiagInfo[] = {
+#define DIAG(ENUM,CLASS,DEFAULT_MAPPING,DESC,GROUP,               \
+             SFINAE,ACCESS,NOWERROR,SHOWINSYSHEADER,              \
+             CATEGORY)                                            \
+  { diag::ENUM, DEFAULT_MAPPING, CLASS, SFINAE, ACCESS,           \
+    NOWERROR, SHOWINSYSHEADER, CATEGORY, GROUP,                   \
+    STR_SIZE(DESC, uint16_t), DESC },
+#include "clang/Basic/DiagnosticCommonKinds.inc"
+#include "clang/Basic/DiagnosticDriverKinds.inc"
+#include "clang/Basic/DiagnosticFrontendKinds.inc"
+#include "clang/Basic/DiagnosticSerializationKinds.inc"
+#include "clang/Basic/DiagnosticLexKinds.inc"
+#include "clang/Basic/DiagnosticParseKinds.inc"
+#include "clang/Basic/DiagnosticASTKinds.inc"
+#include "clang/Basic/DiagnosticSemaKinds.inc"
+#include "clang/Basic/DiagnosticAnalysisKinds.inc"
+#undef DIAG
+  { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
+};
+
+static const unsigned StaticDiagInfoSize =
+  sizeof(StaticDiagInfo)/sizeof(StaticDiagInfo[0])-1;
+
+/// GetDiagInfo - Return the StaticDiagInfoRec entry for the specified DiagID,
+/// or null if the ID is invalid.
+static const StaticDiagInfoRec *GetDiagInfo(unsigned DiagID) {
+  // If assertions are enabled, verify that the StaticDiagInfo array is sorted.
+#ifndef NDEBUG
+  static bool IsFirst = true;
+  if (IsFirst) {
+    for (unsigned i = 1; i != StaticDiagInfoSize; ++i) {
+      assert(StaticDiagInfo[i-1].DiagID != StaticDiagInfo[i].DiagID &&
+             "Diag ID conflict, the enums at the start of clang::diag (in "
+             "DiagnosticIDs.h) probably need to be increased");
+
+      assert(StaticDiagInfo[i-1] < StaticDiagInfo[i] &&
+             "Improperly sorted diag info");
+    }
+    IsFirst = false;
+  }
+#endif
+
+  // Search the diagnostic table with a binary search.
+  StaticDiagInfoRec Find = { static_cast<unsigned short>(DiagID),
+                             0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+
+  const StaticDiagInfoRec *Found =
+    std::lower_bound(StaticDiagInfo, StaticDiagInfo + StaticDiagInfoSize, Find);
+  if (Found == StaticDiagInfo + StaticDiagInfoSize ||
+      Found->DiagID != DiagID)
+    return 0;
+
+  return Found;
+}
+
+static DiagnosticMappingInfo GetDefaultDiagMappingInfo(unsigned DiagID) {
+  DiagnosticMappingInfo Info = DiagnosticMappingInfo::Make(
+    diag::MAP_FATAL, /*IsUser=*/false, /*IsPragma=*/false);
+
+  if (const StaticDiagInfoRec *StaticInfo = GetDiagInfo(DiagID)) {
+    Info.setMapping((diag::Mapping) StaticInfo->Mapping);
+
+    if (StaticInfo->WarnNoWerror) {
+      assert(Info.getMapping() == diag::MAP_WARNING &&
+             "Unexpected mapping with no-Werror bit!");
+      Info.setNoWarningAsError(true);
+    }
+
+    if (StaticInfo->WarnShowInSystemHeader) {
+      assert(Info.getMapping() == diag::MAP_WARNING &&
+             "Unexpected mapping with show-in-system-header bit!");
+      Info.setShowInSystemHeader(true);
+    }
+  }
+
+  return Info;
+}
+
+/// getCategoryNumberForDiag - Return the category number that a specified
+/// DiagID belongs to, or 0 if no category.
+unsigned DiagnosticIDs::getCategoryNumberForDiag(unsigned DiagID) {
+  if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID))
+    return Info->Category;
+  return 0;
+}
+
+namespace {
+  // The diagnostic category names.
+  struct StaticDiagCategoryRec {
+    const char *NameStr;
+    uint8_t NameLen;
+
+    StringRef getName() const {
+      return StringRef(NameStr, NameLen);
+    }
+  };
+}
+
+// Unfortunately, the split between DiagnosticIDs and Diagnostic is not
+// particularly clean, but for now we just implement this method here so we can
+// access GetDefaultDiagMapping.
+DiagnosticMappingInfo &DiagnosticsEngine::DiagState::getOrAddMappingInfo(
+  diag::kind Diag)
+{
+  std::pair<iterator, bool> Result = DiagMap.insert(
+    std::make_pair(Diag, DiagnosticMappingInfo()));
+
+  // Initialize the entry if we added it.
+  if (Result.second)
+    Result.first->second = GetDefaultDiagMappingInfo(Diag);
+
+  return Result.first->second;
+}
+
+static const StaticDiagCategoryRec CategoryNameTable[] = {
+#define GET_CATEGORY_TABLE
+#define CATEGORY(X, ENUM) { X, STR_SIZE(X, uint8_t) },
+#include "clang/Basic/DiagnosticGroups.inc"
+#undef GET_CATEGORY_TABLE
+  { 0, 0 }
+};
+
+/// getNumberOfCategories - Return the number of categories
+unsigned DiagnosticIDs::getNumberOfCategories() {
+  return sizeof(CategoryNameTable) / sizeof(CategoryNameTable[0])-1;
+}
+
+/// getCategoryNameFromID - Given a category ID, return the name of the
+/// category, an empty string if CategoryID is zero, or null if CategoryID is
+/// invalid.
+StringRef DiagnosticIDs::getCategoryNameFromID(unsigned CategoryID) {
+  if (CategoryID >= getNumberOfCategories())
+   return StringRef();
+  return CategoryNameTable[CategoryID].getName();
+}
+
+
+
+DiagnosticIDs::SFINAEResponse 
+DiagnosticIDs::getDiagnosticSFINAEResponse(unsigned DiagID) {
+  if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID)) {
+    if (Info->AccessControl)
+      return SFINAE_AccessControl;
+    
+    if (!Info->SFINAE)
+      return SFINAE_Report;
+
+    if (Info->Class == CLASS_ERROR)
+      return SFINAE_SubstitutionFailure;
+    
+    // Suppress notes, warnings, and extensions;
+    return SFINAE_Suppress;
+  }
+  
+  return SFINAE_Report;
+}
+
+/// getBuiltinDiagClass - Return the class field of the diagnostic.
+///
+static unsigned getBuiltinDiagClass(unsigned DiagID) {
+  if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID))
+    return Info->Class;
+  return ~0U;
+}
+
+//===----------------------------------------------------------------------===//
+// Custom Diagnostic information
+//===----------------------------------------------------------------------===//
+
+namespace clang {
+  namespace diag {
+    class CustomDiagInfo {
+      typedef std::pair<DiagnosticIDs::Level, std::string> DiagDesc;
+      std::vector<DiagDesc> DiagInfo;
+      std::map<DiagDesc, unsigned> DiagIDs;
+    public:
+
+      /// getDescription - Return the description of the specified custom
+      /// diagnostic.
+      StringRef getDescription(unsigned DiagID) const {
+        assert(this && DiagID-DIAG_UPPER_LIMIT < DiagInfo.size() &&
+               "Invalid diagnosic ID");
+        return DiagInfo[DiagID-DIAG_UPPER_LIMIT].second;
+      }
+
+      /// getLevel - Return the level of the specified custom diagnostic.
+      DiagnosticIDs::Level getLevel(unsigned DiagID) const {
+        assert(this && DiagID-DIAG_UPPER_LIMIT < DiagInfo.size() &&
+               "Invalid diagnosic ID");
+        return DiagInfo[DiagID-DIAG_UPPER_LIMIT].first;
+      }
+
+      unsigned getOrCreateDiagID(DiagnosticIDs::Level L, StringRef Message,
+                                 DiagnosticIDs &Diags) {
+        DiagDesc D(L, Message);
+        // Check to see if it already exists.
+        std::map<DiagDesc, unsigned>::iterator I = DiagIDs.lower_bound(D);
+        if (I != DiagIDs.end() && I->first == D)
+          return I->second;
+
+        // If not, assign a new ID.
+        unsigned ID = DiagInfo.size()+DIAG_UPPER_LIMIT;
+        DiagIDs.insert(std::make_pair(D, ID));
+        DiagInfo.push_back(D);
+        return ID;
+      }
+    };
+
+  } // end diag namespace
+} // end clang namespace
+
+
+//===----------------------------------------------------------------------===//
+// Common Diagnostic implementation
+//===----------------------------------------------------------------------===//
+
+DiagnosticIDs::DiagnosticIDs() {
+  CustomDiagInfo = 0;
+}
+
+DiagnosticIDs::~DiagnosticIDs() {
+  delete CustomDiagInfo;
+}
+
+/// getCustomDiagID - Return an ID for a diagnostic with the specified message
+/// and level.  If this is the first request for this diagnosic, it is
+/// registered and created, otherwise the existing ID is returned.
+unsigned DiagnosticIDs::getCustomDiagID(Level L, StringRef Message) {
+  if (CustomDiagInfo == 0)
+    CustomDiagInfo = new diag::CustomDiagInfo();
+  return CustomDiagInfo->getOrCreateDiagID(L, Message, *this);
+}
+
+
+/// isBuiltinWarningOrExtension - Return true if the unmapped diagnostic
+/// level of the specified diagnostic ID is a Warning or Extension.
+/// This only works on builtin diagnostics, not custom ones, and is not legal to
+/// call on NOTEs.
+bool DiagnosticIDs::isBuiltinWarningOrExtension(unsigned DiagID) {
+  return DiagID < diag::DIAG_UPPER_LIMIT &&
+         getBuiltinDiagClass(DiagID) != CLASS_ERROR;
+}
+
+/// \brief Determine whether the given built-in diagnostic ID is a
+/// Note.
+bool DiagnosticIDs::isBuiltinNote(unsigned DiagID) {
+  return DiagID < diag::DIAG_UPPER_LIMIT &&
+    getBuiltinDiagClass(DiagID) == CLASS_NOTE;
+}
+
+/// isBuiltinExtensionDiag - Determine whether the given built-in diagnostic
+/// ID is for an extension of some sort.  This also returns EnabledByDefault,
+/// which is set to indicate whether the diagnostic is ignored by default (in
+/// which case -pedantic enables it) or treated as a warning/error by default.
+///
+bool DiagnosticIDs::isBuiltinExtensionDiag(unsigned DiagID,
+                                        bool &EnabledByDefault) {
+  if (DiagID >= diag::DIAG_UPPER_LIMIT ||
+      getBuiltinDiagClass(DiagID) != CLASS_EXTENSION)
+    return false;
+  
+  EnabledByDefault =
+    GetDefaultDiagMappingInfo(DiagID).getMapping() != diag::MAP_IGNORE;
+  return true;
+}
+
+bool DiagnosticIDs::isDefaultMappingAsError(unsigned DiagID) {
+  if (DiagID >= diag::DIAG_UPPER_LIMIT)
+    return false;
+
+  return GetDefaultDiagMappingInfo(DiagID).getMapping() == diag::MAP_ERROR;
+}
+
+/// getDescription - Given a diagnostic ID, return a description of the
+/// issue.
+StringRef DiagnosticIDs::getDescription(unsigned DiagID) const {
+  if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID))
+    return Info->getDescription();
+  return CustomDiagInfo->getDescription(DiagID);
+}
+
+/// getDiagnosticLevel - Based on the way the client configured the
+/// DiagnosticsEngine object, classify the specified diagnostic ID into a Level,
+/// by consumable the DiagnosticClient.
+DiagnosticIDs::Level
+DiagnosticIDs::getDiagnosticLevel(unsigned DiagID, SourceLocation Loc,
+                                  const DiagnosticsEngine &Diag) const {
+  // Handle custom diagnostics, which cannot be mapped.
+  if (DiagID >= diag::DIAG_UPPER_LIMIT)
+    return CustomDiagInfo->getLevel(DiagID);
+
+  unsigned DiagClass = getBuiltinDiagClass(DiagID);
+  assert(DiagClass != CLASS_NOTE && "Cannot get diagnostic level of a note!");
+  return getDiagnosticLevel(DiagID, DiagClass, Loc, Diag);
+}
+
+/// \brief Based on the way the client configured the Diagnostic
+/// object, classify the specified diagnostic ID into a Level, consumable by
+/// the DiagnosticClient.
+///
+/// \param Loc The source location we are interested in finding out the
+/// diagnostic state. Can be null in order to query the latest state.
+DiagnosticIDs::Level
+DiagnosticIDs::getDiagnosticLevel(unsigned DiagID, unsigned DiagClass,
+                                  SourceLocation Loc,
+                                  const DiagnosticsEngine &Diag) const {
+  // Specific non-error diagnostics may be mapped to various levels from ignored
+  // to error.  Errors can only be mapped to fatal.
+  DiagnosticIDs::Level Result = DiagnosticIDs::Fatal;
+
+  DiagnosticsEngine::DiagStatePointsTy::iterator
+    Pos = Diag.GetDiagStatePointForLoc(Loc);
+  DiagnosticsEngine::DiagState *State = Pos->State;
+
+  // Get the mapping information, or compute it lazily.
+  DiagnosticMappingInfo &MappingInfo = State->getOrAddMappingInfo(
+    (diag::kind)DiagID);
+
+  switch (MappingInfo.getMapping()) {
+  case diag::MAP_IGNORE:
+    Result = DiagnosticIDs::Ignored;
+    break;
+  case diag::MAP_WARNING:
+    Result = DiagnosticIDs::Warning;
+    break;
+  case diag::MAP_ERROR:
+    Result = DiagnosticIDs::Error;
+    break;
+  case diag::MAP_FATAL:
+    Result = DiagnosticIDs::Fatal;
+    break;
+  }
+
+  // Upgrade ignored diagnostics if -Weverything is enabled.
+  if (Diag.EnableAllWarnings && Result == DiagnosticIDs::Ignored &&
+      !MappingInfo.isUser())
+    Result = DiagnosticIDs::Warning;
+
+  // Ignore -pedantic diagnostics inside __extension__ blocks.
+  // (The diagnostics controlled by -pedantic are the extension diagnostics
+  // that are not enabled by default.)
+  bool EnabledByDefault = false;
+  bool IsExtensionDiag = isBuiltinExtensionDiag(DiagID, EnabledByDefault);
+  if (Diag.AllExtensionsSilenced && IsExtensionDiag && !EnabledByDefault)
+    return DiagnosticIDs::Ignored;
+
+  // For extension diagnostics that haven't been explicitly mapped, check if we
+  // should upgrade the diagnostic.
+  if (IsExtensionDiag && !MappingInfo.isUser()) {
+    switch (Diag.ExtBehavior) {
+    case DiagnosticsEngine::Ext_Ignore:
+      break; 
+    case DiagnosticsEngine::Ext_Warn:
+      // Upgrade ignored diagnostics to warnings.
+      if (Result == DiagnosticIDs::Ignored)
+        Result = DiagnosticIDs::Warning;
+      break;
+    case DiagnosticsEngine::Ext_Error:
+      // Upgrade ignored or warning diagnostics to errors.
+      if (Result == DiagnosticIDs::Ignored || Result == DiagnosticIDs::Warning)
+        Result = DiagnosticIDs::Error;
+      break;
+    }
+  }
+
+  // At this point, ignored errors can no longer be upgraded.
+  if (Result == DiagnosticIDs::Ignored)
+    return Result;
+
+  // Honor -w, which is lower in priority than pedantic-errors, but higher than
+  // -Werror.
+  if (Result == DiagnosticIDs::Warning && Diag.IgnoreAllWarnings)
+    return DiagnosticIDs::Ignored;
+
+  // If -Werror is enabled, map warnings to errors unless explicitly disabled.
+  if (Result == DiagnosticIDs::Warning) {
+    if (Diag.WarningsAsErrors && !MappingInfo.hasNoWarningAsError())
+      Result = DiagnosticIDs::Error;
+  }
+
+  // If -Wfatal-errors is enabled, map errors to fatal unless explicity
+  // disabled.
+  if (Result == DiagnosticIDs::Error) {
+    if (Diag.ErrorsAsFatal && !MappingInfo.hasNoErrorAsFatal())
+      Result = DiagnosticIDs::Fatal;
+  }
+
+  // If we are in a system header, we ignore it. We look at the diagnostic class
+  // because we also want to ignore extensions and warnings in -Werror and
+  // -pedantic-errors modes, which *map* warnings/extensions to errors.
+  if (Result >= DiagnosticIDs::Warning &&
+      DiagClass != CLASS_ERROR &&
+      // Custom diagnostics always are emitted in system headers.
+      DiagID < diag::DIAG_UPPER_LIMIT &&
+      !MappingInfo.hasShowInSystemHeader() &&
+      Diag.SuppressSystemWarnings &&
+      Loc.isValid() &&
+      Diag.getSourceManager().isInSystemHeader(
+          Diag.getSourceManager().getExpansionLoc(Loc)))
+    return DiagnosticIDs::Ignored;
+
+  return Result;
+}
+
+struct clang::WarningOption {
+  // Be safe with the size of 'NameLen' because we don't statically check if
+  // the size will fit in the field; the struct size won't decrease with a
+  // shorter type anyway.
+  size_t NameLen;
+  const char *NameStr;
+  const short *Members;
+  const short *SubGroups;
+
+  StringRef getName() const {
+    return StringRef(NameStr, NameLen);
+  }
+};
+
+#define GET_DIAG_ARRAYS
+#include "clang/Basic/DiagnosticGroups.inc"
+#undef GET_DIAG_ARRAYS
+
+// Second the table of options, sorted by name for fast binary lookup.
+static const WarningOption OptionTable[] = {
+#define GET_DIAG_TABLE
+#include "clang/Basic/DiagnosticGroups.inc"
+#undef GET_DIAG_TABLE
+};
+static const size_t OptionTableSize =
+sizeof(OptionTable) / sizeof(OptionTable[0]);
+
+static bool WarningOptionCompare(const WarningOption &LHS,
+                                 const WarningOption &RHS) {
+  return LHS.getName() < RHS.getName();
+}
+
+/// getWarningOptionForDiag - Return the lowest-level warning option that
+/// enables the specified diagnostic.  If there is no -Wfoo flag that controls
+/// the diagnostic, this returns null.
+StringRef DiagnosticIDs::getWarningOptionForDiag(unsigned DiagID) {
+  if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID))
+    return OptionTable[Info->getOptionGroupIndex()].getName();
+  return StringRef();
+}
+
+void DiagnosticIDs::getDiagnosticsInGroup(
+  const WarningOption *Group,
+  llvm::SmallVectorImpl<diag::kind> &Diags) const
+{
+  // Add the members of the option diagnostic set.
+  if (const short *Member = Group->Members) {
+    for (; *Member != -1; ++Member)
+      Diags.push_back(*Member);
+  }
+
+  // Add the members of the subgroups.
+  if (const short *SubGroups = Group->SubGroups) {
+    for (; *SubGroups != (short)-1; ++SubGroups)
+      getDiagnosticsInGroup(&OptionTable[(short)*SubGroups], Diags);
+  }
+}
+
+bool DiagnosticIDs::getDiagnosticsInGroup(
+  StringRef Group,
+  llvm::SmallVectorImpl<diag::kind> &Diags) const
+{
+  WarningOption Key = { Group.size(), Group.data(), 0, 0 };
+  const WarningOption *Found =
+  std::lower_bound(OptionTable, OptionTable + OptionTableSize, Key,
+                   WarningOptionCompare);
+  if (Found == OptionTable + OptionTableSize ||
+      Found->getName() != Group)
+    return true; // Option not found.
+
+  getDiagnosticsInGroup(Found, Diags);
+  return false;
+}
+
+void DiagnosticIDs::getAllDiagnostics(
+                               llvm::SmallVectorImpl<diag::kind> &Diags) const {
+  for (unsigned i = 0; i != StaticDiagInfoSize; ++i)
+    Diags.push_back(StaticDiagInfo[i].DiagID);
+}
+
+StringRef DiagnosticIDs::getNearestWarningOption(StringRef Group) {
+  StringRef Best;
+  unsigned BestDistance = Group.size() + 1; // Sanity threshold.
+  for (const WarningOption *i = OptionTable, *e = OptionTable + OptionTableSize;
+       i != e; ++i) {
+    // Don't suggest ignored warning flags.
+    if (!i->Members && !i->SubGroups)
+      continue;
+
+    unsigned Distance = i->getName().edit_distance(Group, true, BestDistance);
+    if (Distance == BestDistance) {
+      // Two matches with the same distance, don't prefer one over the other.
+      Best = "";
+    } else if (Distance < BestDistance) {
+      // This is a better match.
+      Best = i->getName();
+      BestDistance = Distance;
+    }
+  }
+
+  return Best;
+}
+
+/// ProcessDiag - This is the method used to report a diagnostic that is
+/// finally fully formed.
+bool DiagnosticIDs::ProcessDiag(DiagnosticsEngine &Diag) const {
+  Diagnostic Info(&Diag);
+
+  if (Diag.SuppressAllDiagnostics)
+    return false;
+
+  assert(Diag.getClient() && "DiagnosticClient not set!");
+
+  // Figure out the diagnostic level of this message.
+  DiagnosticIDs::Level DiagLevel;
+  unsigned DiagID = Info.getID();
+
+  if (DiagID >= diag::DIAG_UPPER_LIMIT) {
+    // Handle custom diagnostics, which cannot be mapped.
+    DiagLevel = CustomDiagInfo->getLevel(DiagID);
+  } else {
+    // Get the class of the diagnostic.  If this is a NOTE, map it onto whatever
+    // the diagnostic level was for the previous diagnostic so that it is
+    // filtered the same as the previous diagnostic.
+    unsigned DiagClass = getBuiltinDiagClass(DiagID);
+    if (DiagClass == CLASS_NOTE) {
+      DiagLevel = DiagnosticIDs::Note;
+    } else {
+      DiagLevel = getDiagnosticLevel(DiagID, DiagClass, Info.getLocation(),
+                                     Diag);
+    }
+  }
+
+  if (DiagLevel != DiagnosticIDs::Note) {
+    // Record that a fatal error occurred only when we see a second
+    // non-note diagnostic. This allows notes to be attached to the
+    // fatal error, but suppresses any diagnostics that follow those
+    // notes.
+    if (Diag.LastDiagLevel == DiagnosticIDs::Fatal)
+      Diag.FatalErrorOccurred = true;
+
+    Diag.LastDiagLevel = DiagLevel;
+  }
+
+  // Update counts for DiagnosticErrorTrap even if a fatal error occurred.
+  if (DiagLevel >= DiagnosticIDs::Error) {
+    ++Diag.TrapNumErrorsOccurred;
+    if (isUnrecoverable(DiagID))
+      ++Diag.TrapNumUnrecoverableErrorsOccurred;
+  }
+
+  // If a fatal error has already been emitted, silence all subsequent
+  // diagnostics.
+  if (Diag.FatalErrorOccurred) {
+    if (DiagLevel >= DiagnosticIDs::Error &&
+        Diag.Client->IncludeInDiagnosticCounts()) {
+      ++Diag.NumErrors;
+      ++Diag.NumErrorsSuppressed;
+    }
+
+    return false;
+  }
+
+  // If the client doesn't care about this message, don't issue it.  If this is
+  // a note and the last real diagnostic was ignored, ignore it too.
+  if (DiagLevel == DiagnosticIDs::Ignored ||
+      (DiagLevel == DiagnosticIDs::Note &&
+       Diag.LastDiagLevel == DiagnosticIDs::Ignored))
+    return false;
+
+  if (DiagLevel >= DiagnosticIDs::Error) {
+    if (isUnrecoverable(DiagID))
+      Diag.UnrecoverableErrorOccurred = true;
+    
+    if (Diag.Client->IncludeInDiagnosticCounts()) {
+      Diag.ErrorOccurred = true;
+      ++Diag.NumErrors;
+    }
+
+    // If we've emitted a lot of errors, emit a fatal error instead of it to 
+    // stop a flood of bogus errors.
+    if (Diag.ErrorLimit && Diag.NumErrors > Diag.ErrorLimit &&
+        DiagLevel == DiagnosticIDs::Error) {
+      Diag.SetDelayedDiagnostic(diag::fatal_too_many_errors);
+      return false;
+    }
+  }
+
+  // Finally, report it.
+  Diag.Client->HandleDiagnostic((DiagnosticsEngine::Level)DiagLevel, Info);
+  if (Diag.Client->IncludeInDiagnosticCounts()) {
+    if (DiagLevel == DiagnosticIDs::Warning)
+      ++Diag.NumWarnings;
+  }
+
+  Diag.CurDiagID = ~0U;
+
+  return true;
+}
+
+bool DiagnosticIDs::isUnrecoverable(unsigned DiagID) const {
+  if (DiagID >= diag::DIAG_UPPER_LIMIT) {
+    // Custom diagnostics.
+    return CustomDiagInfo->getLevel(DiagID) >= DiagnosticIDs::Error;
+  }
+
+  // Only errors may be unrecoverable.
+  if (getBuiltinDiagClass(DiagID) < CLASS_ERROR)
+    return false;
+
+  if (DiagID == diag::err_unavailable ||
+      DiagID == diag::err_unavailable_message)
+    return false;
+
+  // Currently we consider all ARC errors as recoverable.
+  if (isARCDiagnostic(DiagID))
+    return false;
+
+  return true;
+}
+
+bool DiagnosticIDs::isARCDiagnostic(unsigned DiagID) {
+  unsigned cat = getCategoryNumberForDiag(DiagID);
+  return DiagnosticIDs::getCategoryNameFromID(cat).startswith("ARC ");
+}
+