Export clang-format16 via ydblib project

6e6be3a95868fde888d801b7590af4044049563f

1 files changed, 634 insertions, 0 deletions

diff --git a/contrib/libs/clang16/lib/Frontend/DiagnosticRenderer.cpp b/contrib/libs/clang16/lib/Frontend/DiagnosticRenderer.cpp
new file mode 100644
index 0000000000..9177ba9f4f
--- /dev/null
+++ b/contrib/libs/clang16/lib/Frontend/DiagnosticRenderer.cpp
@@ -0,0 +1,634 @@
+//===- DiagnosticRenderer.cpp - Diagnostic Pretty-Printing ----------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Frontend/DiagnosticRenderer.h"
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Basic/LLVM.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Edit/Commit.h"
+#include "clang/Edit/EditedSource.h"
+#include "clang/Edit/EditsReceiver.h"
+#include "clang/Lex/Lexer.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+#include <iterator>
+#include <utility>
+
+using namespace clang;
+
+DiagnosticRenderer::DiagnosticRenderer(const LangOptions &LangOpts,
+                                       DiagnosticOptions *DiagOpts)
+    : LangOpts(LangOpts), DiagOpts(DiagOpts), LastLevel() {}
+
+DiagnosticRenderer::~DiagnosticRenderer() = default;
+
+namespace {
+
+class FixitReceiver : public edit::EditsReceiver {
+  SmallVectorImpl<FixItHint> &MergedFixits;
+
+public:
+  FixitReceiver(SmallVectorImpl<FixItHint> &MergedFixits)
+      : MergedFixits(MergedFixits) {}
+
+  void insert(SourceLocation loc, StringRef text) override {
+    MergedFixits.push_back(FixItHint::CreateInsertion(loc, text));
+  }
+
+  void replace(CharSourceRange range, StringRef text) override {
+    MergedFixits.push_back(FixItHint::CreateReplacement(range, text));
+  }
+};
+
+} // namespace
+
+static void mergeFixits(ArrayRef<FixItHint> FixItHints,
+                        const SourceManager &SM, const LangOptions &LangOpts,
+                        SmallVectorImpl<FixItHint> &MergedFixits) {
+  edit::Commit commit(SM, LangOpts);
+  for (const auto &Hint : FixItHints)
+    if (Hint.CodeToInsert.empty()) {
+      if (Hint.InsertFromRange.isValid())
+        commit.insertFromRange(Hint.RemoveRange.getBegin(),
+                           Hint.InsertFromRange, /*afterToken=*/false,
+                           Hint.BeforePreviousInsertions);
+      else
+        commit.remove(Hint.RemoveRange);
+    } else {
+      if (Hint.RemoveRange.isTokenRange() ||
+          Hint.RemoveRange.getBegin() != Hint.RemoveRange.getEnd())
+        commit.replace(Hint.RemoveRange, Hint.CodeToInsert);
+      else
+        commit.insert(Hint.RemoveRange.getBegin(), Hint.CodeToInsert,
+                    /*afterToken=*/false, Hint.BeforePreviousInsertions);
+    }
+
+  edit::EditedSource Editor(SM, LangOpts);
+  if (Editor.commit(commit)) {
+    FixitReceiver Rec(MergedFixits);
+    Editor.applyRewrites(Rec);
+  }
+}
+
+void DiagnosticRenderer::emitDiagnostic(FullSourceLoc Loc,
+                                        DiagnosticsEngine::Level Level,
+                                        StringRef Message,
+                                        ArrayRef<CharSourceRange> Ranges,
+                                        ArrayRef<FixItHint> FixItHints,
+                                        DiagOrStoredDiag D) {
+  assert(Loc.hasManager() || Loc.isInvalid());
+
+  beginDiagnostic(D, Level);
+
+  if (!Loc.isValid())
+    // If we have no source location, just emit the diagnostic message.
+    emitDiagnosticMessage(Loc, PresumedLoc(), Level, Message, Ranges, D);
+  else {
+    // Get the ranges into a local array we can hack on.
+    SmallVector<CharSourceRange, 20> MutableRanges(Ranges.begin(),
+                                                   Ranges.end());
+
+    SmallVector<FixItHint, 8> MergedFixits;
+    if (!FixItHints.empty()) {
+      mergeFixits(FixItHints, Loc.getManager(), LangOpts, MergedFixits);
+      FixItHints = MergedFixits;
+    }
+
+    for (const auto &Hint : FixItHints)
+      if (Hint.RemoveRange.isValid())
+        MutableRanges.push_back(Hint.RemoveRange);
+
+    FullSourceLoc UnexpandedLoc = Loc;
+
+    // Find the ultimate expansion location for the diagnostic.
+    Loc = Loc.getFileLoc();
+
+    PresumedLoc PLoc = Loc.getPresumedLoc(DiagOpts->ShowPresumedLoc);
+
+    // First, if this diagnostic is not in the main file, print out the
+    // "included from" lines.
+    emitIncludeStack(Loc, PLoc, Level);
+
+    // Next, emit the actual diagnostic message and caret.
+    emitDiagnosticMessage(Loc, PLoc, Level, Message, Ranges, D);
+    emitCaret(Loc, Level, MutableRanges, FixItHints);
+
+    // If this location is within a macro, walk from UnexpandedLoc up to Loc
+    // and produce a macro backtrace.
+    if (UnexpandedLoc.isValid() && UnexpandedLoc.isMacroID()) {
+      emitMacroExpansions(UnexpandedLoc, Level, MutableRanges, FixItHints);
+    }
+  }
+
+  LastLoc = Loc;
+  LastLevel = Level;
+
+  endDiagnostic(D, Level);
+}
+
+void DiagnosticRenderer::emitStoredDiagnostic(StoredDiagnostic &Diag) {
+  emitDiagnostic(Diag.getLocation(), Diag.getLevel(), Diag.getMessage(),
+                 Diag.getRanges(), Diag.getFixIts(),
+                 &Diag);
+}
+
+void DiagnosticRenderer::emitBasicNote(StringRef Message) {
+  emitDiagnosticMessage(FullSourceLoc(), PresumedLoc(), DiagnosticsEngine::Note,
+                        Message, std::nullopt, DiagOrStoredDiag());
+}
+
+/// Prints an include stack when appropriate for a particular
+/// diagnostic level and location.
+///
+/// This routine handles all the logic of suppressing particular include
+/// stacks (such as those for notes) and duplicate include stacks when
+/// repeated warnings occur within the same file. It also handles the logic
+/// of customizing the formatting and display of the include stack.
+///
+/// \param Loc   The diagnostic location.
+/// \param PLoc  The presumed location of the diagnostic location.
+/// \param Level The diagnostic level of the message this stack pertains to.
+void DiagnosticRenderer::emitIncludeStack(FullSourceLoc Loc, PresumedLoc PLoc,
+                                          DiagnosticsEngine::Level Level) {
+  FullSourceLoc IncludeLoc =
+      PLoc.isInvalid() ? FullSourceLoc()
+                       : FullSourceLoc(PLoc.getIncludeLoc(), Loc.getManager());
+
+  // Skip redundant include stacks altogether.
+  if (LastIncludeLoc == IncludeLoc)
+    return;
+
+  LastIncludeLoc = IncludeLoc;
+
+  if (!DiagOpts->ShowNoteIncludeStack && Level == DiagnosticsEngine::Note)
+    return;
+
+  if (IncludeLoc.isValid())
+    emitIncludeStackRecursively(IncludeLoc);
+  else {
+    emitModuleBuildStack(Loc.getManager());
+    emitImportStack(Loc);
+  }
+}
+
+/// Helper to recursively walk up the include stack and print each layer
+/// on the way back down.
+void DiagnosticRenderer::emitIncludeStackRecursively(FullSourceLoc Loc) {
+  if (Loc.isInvalid()) {
+    emitModuleBuildStack(Loc.getManager());
+    return;
+  }
+
+  PresumedLoc PLoc = Loc.getPresumedLoc(DiagOpts->ShowPresumedLoc);
+  if (PLoc.isInvalid())
+    return;
+
+  // If this source location was imported from a module, print the module
+  // import stack rather than the
+  // FIXME: We want submodule granularity here.
+  std::pair<FullSourceLoc, StringRef> Imported = Loc.getModuleImportLoc();
+  if (!Imported.second.empty()) {
+    // This location was imported by a module. Emit the module import stack.
+    emitImportStackRecursively(Imported.first, Imported.second);
+    return;
+  }
+
+  // Emit the other include frames first.
+  emitIncludeStackRecursively(
+      FullSourceLoc(PLoc.getIncludeLoc(), Loc.getManager()));
+
+  // Emit the inclusion text/note.
+  emitIncludeLocation(Loc, PLoc);
+}
+
+/// Emit the module import stack associated with the current location.
+void DiagnosticRenderer::emitImportStack(FullSourceLoc Loc) {
+  if (Loc.isInvalid()) {
+    emitModuleBuildStack(Loc.getManager());
+    return;
+  }
+
+  std::pair<FullSourceLoc, StringRef> NextImportLoc = Loc.getModuleImportLoc();
+  emitImportStackRecursively(NextImportLoc.first, NextImportLoc.second);
+}
+
+/// Helper to recursively walk up the import stack and print each layer
+/// on the way back down.
+void DiagnosticRenderer::emitImportStackRecursively(FullSourceLoc Loc,
+                                                    StringRef ModuleName) {
+  if (ModuleName.empty()) {
+    return;
+  }
+
+  PresumedLoc PLoc = Loc.getPresumedLoc(DiagOpts->ShowPresumedLoc);
+
+  // Emit the other import frames first.
+  std::pair<FullSourceLoc, StringRef> NextImportLoc = Loc.getModuleImportLoc();
+  emitImportStackRecursively(NextImportLoc.first, NextImportLoc.second);
+
+  // Emit the inclusion text/note.
+  emitImportLocation(Loc, PLoc, ModuleName);
+}
+
+/// Emit the module build stack, for cases where a module is (re-)built
+/// on demand.
+void DiagnosticRenderer::emitModuleBuildStack(const SourceManager &SM) {
+  ModuleBuildStack Stack = SM.getModuleBuildStack();
+  for (const auto &I : Stack) {
+    emitBuildingModuleLocation(I.second, I.second.getPresumedLoc(
+                                              DiagOpts->ShowPresumedLoc),
+                               I.first);
+  }
+}
+
+/// A recursive function to trace all possible backtrace locations
+/// to match the \p CaretLocFileID.
+static SourceLocation
+retrieveMacroLocation(SourceLocation Loc, FileID MacroFileID,
+                      FileID CaretFileID,
+                      const SmallVectorImpl<FileID> &CommonArgExpansions,
+                      bool IsBegin, const SourceManager *SM,
+                      bool &IsTokenRange) {
+  assert(SM->getFileID(Loc) == MacroFileID);
+  if (MacroFileID == CaretFileID)
+    return Loc;
+  if (!Loc.isMacroID())
+    return {};
+
+  CharSourceRange MacroRange, MacroArgRange;
+
+  if (SM->isMacroArgExpansion(Loc)) {
+    // Only look at the immediate spelling location of this macro argument if
+    // the other location in the source range is also present in that expansion.
+    if (std::binary_search(CommonArgExpansions.begin(),
+                           CommonArgExpansions.end(), MacroFileID))
+      MacroRange =
+          CharSourceRange(SM->getImmediateSpellingLoc(Loc), IsTokenRange);
+    MacroArgRange = SM->getImmediateExpansionRange(Loc);
+  } else {
+    MacroRange = SM->getImmediateExpansionRange(Loc);
+    MacroArgRange =
+        CharSourceRange(SM->getImmediateSpellingLoc(Loc), IsTokenRange);
+  }
+
+  SourceLocation MacroLocation =
+      IsBegin ? MacroRange.getBegin() : MacroRange.getEnd();
+  if (MacroLocation.isValid()) {
+    MacroFileID = SM->getFileID(MacroLocation);
+    bool TokenRange = IsBegin ? IsTokenRange : MacroRange.isTokenRange();
+    MacroLocation =
+        retrieveMacroLocation(MacroLocation, MacroFileID, CaretFileID,
+                              CommonArgExpansions, IsBegin, SM, TokenRange);
+    if (MacroLocation.isValid()) {
+      IsTokenRange = TokenRange;
+      return MacroLocation;
+    }
+  }
+
+  // If we moved the end of the range to an expansion location, we now have
+  // a range of the same kind as the expansion range.
+  if (!IsBegin)
+    IsTokenRange = MacroArgRange.isTokenRange();
+
+  SourceLocation MacroArgLocation =
+      IsBegin ? MacroArgRange.getBegin() : MacroArgRange.getEnd();
+  MacroFileID = SM->getFileID(MacroArgLocation);
+  return retrieveMacroLocation(MacroArgLocation, MacroFileID, CaretFileID,
+                               CommonArgExpansions, IsBegin, SM, IsTokenRange);
+}
+
+/// Walk up the chain of macro expansions and collect the FileIDs identifying the
+/// expansions.
+static void getMacroArgExpansionFileIDs(SourceLocation Loc,
+                                        SmallVectorImpl<FileID> &IDs,
+                                        bool IsBegin, const SourceManager *SM) {
+  while (Loc.isMacroID()) {
+    if (SM->isMacroArgExpansion(Loc)) {
+      IDs.push_back(SM->getFileID(Loc));
+      Loc = SM->getImmediateSpellingLoc(Loc);
+    } else {
+      auto ExpRange = SM->getImmediateExpansionRange(Loc);
+      Loc = IsBegin ? ExpRange.getBegin() : ExpRange.getEnd();
+    }
+  }
+}
+
+/// Collect the expansions of the begin and end locations and compute the set
+/// intersection. Produces a sorted vector of FileIDs in CommonArgExpansions.
+static void computeCommonMacroArgExpansionFileIDs(
+    SourceLocation Begin, SourceLocation End, const SourceManager *SM,
+    SmallVectorImpl<FileID> &CommonArgExpansions) {
+  SmallVector<FileID, 4> BeginArgExpansions;
+  SmallVector<FileID, 4> EndArgExpansions;
+  getMacroArgExpansionFileIDs(Begin, BeginArgExpansions, /*IsBegin=*/true, SM);
+  getMacroArgExpansionFileIDs(End, EndArgExpansions, /*IsBegin=*/false, SM);
+  llvm::sort(BeginArgExpansions);
+  llvm::sort(EndArgExpansions);
+  std::set_intersection(BeginArgExpansions.begin(), BeginArgExpansions.end(),
+                        EndArgExpansions.begin(), EndArgExpansions.end(),
+                        std::back_inserter(CommonArgExpansions));
+}
+
+// Helper function to fix up source ranges.  It takes in an array of ranges,
+// and outputs an array of ranges where we want to draw the range highlighting
+// around the location specified by CaretLoc.
+//
+// To find locations which correspond to the caret, we crawl the macro caller
+// chain for the beginning and end of each range.  If the caret location
+// is in a macro expansion, we search each chain for a location
+// in the same expansion as the caret; otherwise, we crawl to the top of
+// each chain. Two locations are part of the same macro expansion
+// iff the FileID is the same.
+static void
+mapDiagnosticRanges(FullSourceLoc CaretLoc, ArrayRef<CharSourceRange> Ranges,
+                    SmallVectorImpl<CharSourceRange> &SpellingRanges) {
+  FileID CaretLocFileID = CaretLoc.getFileID();
+
+  const SourceManager *SM = &CaretLoc.getManager();
+
+  for (const auto &Range : Ranges) {
+    if (Range.isInvalid())
+      continue;
+
+    SourceLocation Begin = Range.getBegin(), End = Range.getEnd();
+    bool IsTokenRange = Range.isTokenRange();
+
+    FileID BeginFileID = SM->getFileID(Begin);
+    FileID EndFileID = SM->getFileID(End);
+
+    // Find the common parent for the beginning and end of the range.
+
+    // First, crawl the expansion chain for the beginning of the range.
+    llvm::SmallDenseMap<FileID, SourceLocation> BeginLocsMap;
+    while (Begin.isMacroID() && BeginFileID != EndFileID) {
+      BeginLocsMap[BeginFileID] = Begin;
+      Begin = SM->getImmediateExpansionRange(Begin).getBegin();
+      BeginFileID = SM->getFileID(Begin);
+    }
+
+    // Then, crawl the expansion chain for the end of the range.
+    if (BeginFileID != EndFileID) {
+      while (End.isMacroID() && !BeginLocsMap.count(EndFileID)) {
+        auto Exp = SM->getImmediateExpansionRange(End);
+        IsTokenRange = Exp.isTokenRange();
+        End = Exp.getEnd();
+        EndFileID = SM->getFileID(End);
+      }
+      if (End.isMacroID()) {
+        Begin = BeginLocsMap[EndFileID];
+        BeginFileID = EndFileID;
+      }
+    }
+
+    // There is a chance that begin or end is invalid here, for example if
+    // specific compile error is reported.
+    // It is possible that the FileID's do not match, if one comes from an
+    // included file. In this case we can not produce a meaningful source range.
+    if (Begin.isInvalid() || End.isInvalid() || BeginFileID != EndFileID)
+      continue;
+
+    // Do the backtracking.
+    SmallVector<FileID, 4> CommonArgExpansions;
+    computeCommonMacroArgExpansionFileIDs(Begin, End, SM, CommonArgExpansions);
+    Begin = retrieveMacroLocation(Begin, BeginFileID, CaretLocFileID,
+                                  CommonArgExpansions, /*IsBegin=*/true, SM,
+                                  IsTokenRange);
+    End = retrieveMacroLocation(End, BeginFileID, CaretLocFileID,
+                                CommonArgExpansions, /*IsBegin=*/false, SM,
+                                IsTokenRange);
+    if (Begin.isInvalid() || End.isInvalid()) continue;
+
+    // Return the spelling location of the beginning and end of the range.
+    Begin = SM->getSpellingLoc(Begin);
+    End = SM->getSpellingLoc(End);
+
+    SpellingRanges.push_back(CharSourceRange(SourceRange(Begin, End),
+                                             IsTokenRange));
+  }
+}
+
+void DiagnosticRenderer::emitCaret(FullSourceLoc Loc,
+                                   DiagnosticsEngine::Level Level,
+                                   ArrayRef<CharSourceRange> Ranges,
+                                   ArrayRef<FixItHint> Hints) {
+  SmallVector<CharSourceRange, 4> SpellingRanges;
+  mapDiagnosticRanges(Loc, Ranges, SpellingRanges);
+  emitCodeContext(Loc, Level, SpellingRanges, Hints);
+}
+
+/// A helper function for emitMacroExpansion to print the
+/// macro expansion message
+void DiagnosticRenderer::emitSingleMacroExpansion(
+    FullSourceLoc Loc, DiagnosticsEngine::Level Level,
+    ArrayRef<CharSourceRange> Ranges) {
+  // Find the spelling location for the macro definition. We must use the
+  // spelling location here to avoid emitting a macro backtrace for the note.
+  FullSourceLoc SpellingLoc = Loc.getSpellingLoc();
+
+  // Map the ranges into the FileID of the diagnostic location.
+  SmallVector<CharSourceRange, 4> SpellingRanges;
+  mapDiagnosticRanges(Loc, Ranges, SpellingRanges);
+
+  SmallString<100> MessageStorage;
+  llvm::raw_svector_ostream Message(MessageStorage);
+  StringRef MacroName = Lexer::getImmediateMacroNameForDiagnostics(
+      Loc, Loc.getManager(), LangOpts);
+  if (MacroName.empty())
+    Message << "expanded from here";
+  else
+    Message << "expanded from macro '" << MacroName << "'";
+
+  emitDiagnostic(SpellingLoc, DiagnosticsEngine::Note, Message.str(),
+                 SpellingRanges, std::nullopt);
+}
+
+/// Check that the macro argument location of Loc starts with ArgumentLoc.
+/// The starting location of the macro expansions is used to differeniate
+/// different macro expansions.
+static bool checkLocForMacroArgExpansion(SourceLocation Loc,
+                                         const SourceManager &SM,
+                                         SourceLocation ArgumentLoc) {
+  SourceLocation MacroLoc;
+  if (SM.isMacroArgExpansion(Loc, &MacroLoc)) {
+    if (ArgumentLoc == MacroLoc) return true;
+  }
+
+  return false;
+}
+
+/// Check if all the locations in the range have the same macro argument
+/// expansion, and that the expansion starts with ArgumentLoc.
+static bool checkRangeForMacroArgExpansion(CharSourceRange Range,
+                                           const SourceManager &SM,
+                                           SourceLocation ArgumentLoc) {
+  SourceLocation BegLoc = Range.getBegin(), EndLoc = Range.getEnd();
+  while (BegLoc != EndLoc) {
+    if (!checkLocForMacroArgExpansion(BegLoc, SM, ArgumentLoc))
+      return false;
+    BegLoc.getLocWithOffset(1);
+  }
+
+  return checkLocForMacroArgExpansion(BegLoc, SM, ArgumentLoc);
+}
+
+/// A helper function to check if the current ranges are all inside the same
+/// macro argument expansion as Loc.
+static bool checkRangesForMacroArgExpansion(FullSourceLoc Loc,
+                                            ArrayRef<CharSourceRange> Ranges) {
+  assert(Loc.isMacroID() && "Must be a macro expansion!");
+
+  SmallVector<CharSourceRange, 4> SpellingRanges;
+  mapDiagnosticRanges(Loc, Ranges, SpellingRanges);
+
+  /// Count all valid ranges.
+  unsigned ValidCount = 0;
+  for (const auto &Range : Ranges)
+    if (Range.isValid())
+      ValidCount++;
+
+  if (ValidCount > SpellingRanges.size())
+    return false;
+
+  /// To store the source location of the argument location.
+  FullSourceLoc ArgumentLoc;
+
+  /// Set the ArgumentLoc to the beginning location of the expansion of Loc
+  /// so to check if the ranges expands to the same beginning location.
+  if (!Loc.isMacroArgExpansion(&ArgumentLoc))
+    return false;
+
+  for (const auto &Range : SpellingRanges)
+    if (!checkRangeForMacroArgExpansion(Range, Loc.getManager(), ArgumentLoc))
+      return false;
+
+  return true;
+}
+
+/// Recursively emit notes for each macro expansion and caret
+/// diagnostics where appropriate.
+///
+/// Walks up the macro expansion stack printing expansion notes, the code
+/// snippet, caret, underlines and FixItHint display as appropriate at each
+/// level.
+///
+/// \param Loc The location for this caret.
+/// \param Level The diagnostic level currently being emitted.
+/// \param Ranges The underlined ranges for this code snippet.
+/// \param Hints The FixIt hints active for this diagnostic.
+void DiagnosticRenderer::emitMacroExpansions(FullSourceLoc Loc,
+                                             DiagnosticsEngine::Level Level,
+                                             ArrayRef<CharSourceRange> Ranges,
+                                             ArrayRef<FixItHint> Hints) {
+  assert(Loc.isValid() && "must have a valid source location here");
+  const SourceManager &SM = Loc.getManager();
+  SourceLocation L = Loc;
+
+  // Produce a stack of macro backtraces.
+  SmallVector<SourceLocation, 8> LocationStack;
+  unsigned IgnoredEnd = 0;
+  while (L.isMacroID()) {
+    // If this is the expansion of a macro argument, point the caret at the
+    // use of the argument in the definition of the macro, not the expansion.
+    if (SM.isMacroArgExpansion(L))
+      LocationStack.push_back(SM.getImmediateExpansionRange(L).getBegin());
+    else
+      LocationStack.push_back(L);
+
+    if (checkRangesForMacroArgExpansion(FullSourceLoc(L, SM), Ranges))
+      IgnoredEnd = LocationStack.size();
+
+    L = SM.getImmediateMacroCallerLoc(L);
+
+    // Once the location no longer points into a macro, try stepping through
+    // the last found location.  This sometimes produces additional useful
+    // backtraces.
+    if (L.isFileID())
+      L = SM.getImmediateMacroCallerLoc(LocationStack.back());
+    assert(L.isValid() && "must have a valid source location here");
+  }
+
+  LocationStack.erase(LocationStack.begin(),
+                      LocationStack.begin() + IgnoredEnd);
+
+  unsigned MacroDepth = LocationStack.size();
+  unsigned MacroLimit = DiagOpts->MacroBacktraceLimit;
+  if (MacroDepth <= MacroLimit || MacroLimit == 0) {
+    for (auto I = LocationStack.rbegin(), E = LocationStack.rend();
+         I != E; ++I)
+      emitSingleMacroExpansion(FullSourceLoc(*I, SM), Level, Ranges);
+    return;
+  }
+
+  unsigned MacroStartMessages = MacroLimit / 2;
+  unsigned MacroEndMessages = MacroLimit / 2 + MacroLimit % 2;
+
+  for (auto I = LocationStack.rbegin(),
+            E = LocationStack.rbegin() + MacroStartMessages;
+       I != E; ++I)
+    emitSingleMacroExpansion(FullSourceLoc(*I, SM), Level, Ranges);
+
+  SmallString<200> MessageStorage;
+  llvm::raw_svector_ostream Message(MessageStorage);
+  Message << "(skipping " << (MacroDepth - MacroLimit)
+          << " expansions in backtrace; use -fmacro-backtrace-limit=0 to "
+             "see all)";
+  emitBasicNote(Message.str());
+
+  for (auto I = LocationStack.rend() - MacroEndMessages,
+            E = LocationStack.rend();
+       I != E; ++I)
+    emitSingleMacroExpansion(FullSourceLoc(*I, SM), Level, Ranges);
+}
+
+DiagnosticNoteRenderer::~DiagnosticNoteRenderer() = default;
+
+void DiagnosticNoteRenderer::emitIncludeLocation(FullSourceLoc Loc,
+                                                 PresumedLoc PLoc) {
+  // Generate a note indicating the include location.
+  SmallString<200> MessageStorage;
+  llvm::raw_svector_ostream Message(MessageStorage);
+  Message << "in file included from " << PLoc.getFilename() << ':'
+          << PLoc.getLine() << ":";
+  emitNote(Loc, Message.str());
+}
+
+void DiagnosticNoteRenderer::emitImportLocation(FullSourceLoc Loc,
+                                                PresumedLoc PLoc,
+                                                StringRef ModuleName) {
+  // Generate a note indicating the include location.
+  SmallString<200> MessageStorage;
+  llvm::raw_svector_ostream Message(MessageStorage);
+  Message << "in module '" << ModuleName;
+  if (PLoc.isValid())
+    Message << "' imported from " << PLoc.getFilename() << ':'
+            << PLoc.getLine();
+  Message << ":";
+  emitNote(Loc, Message.str());
+}
+
+void DiagnosticNoteRenderer::emitBuildingModuleLocation(FullSourceLoc Loc,
+                                                        PresumedLoc PLoc,
+                                                        StringRef ModuleName) {
+  // Generate a note indicating the include location.
+  SmallString<200> MessageStorage;
+  llvm::raw_svector_ostream Message(MessageStorage);
+  if (PLoc.isValid())
+    Message << "while building module '" << ModuleName << "' imported from "
+            << PLoc.getFilename() << ':' << PLoc.getLine() << ":";
+  else
+    Message << "while building module '" << ModuleName << "':";
+  emitNote(Loc, Message.str());
+}