clang/lib/Frontend/DiagnosticRenderer.cpp - third_party/github.com/llvm/llvm-project - Git at Google

 //===- 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/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);

     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, {}, 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 (llvm::binary_search(CommonArgExpansions, 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, {});
 }

 /// A helper function to check if the current ranges are all inside the same
 /// macro argument expansion as Loc.
 static bool
 rangesInsideSameMacroArgExpansion(FullSourceLoc Loc,
                                   ArrayRef<CharSourceRange> Ranges) {
   assert(Loc.isMacroID() && "Must be a macro expansion!");

   SmallVector<CharSourceRange> SpellingRanges;
   mapDiagnosticRanges(Loc, Ranges, SpellingRanges);

   unsigned ValidCount =
       llvm::count_if(Ranges, [](const auto &R) { return R.isValid(); });
   if (ValidCount > SpellingRanges.size())
     return false;

   const SourceManager &SM = Loc.getManager();
   for (const auto &R : Ranges) {
     // All positions in the range need to point to Loc.
     SourceLocation Begin = R.getBegin();
     if (Begin == R.getEnd()) {
       if (!SM.isMacroArgExpansion(Begin))
         return false;
       continue;
     }

     while (Begin != R.getEnd()) {
       SourceLocation MacroLoc;
       if (!SM.isMacroArgExpansion(Begin, &MacroLoc))
         return false;
       if (MacroLoc != Loc)
         return false;

       Begin = Begin.getLocWithOffset(1);
     }
   }

   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());

       if (rangesInsideSameMacroArgExpansion(FullSourceLoc(L, SM), Ranges))
         IgnoredEnd = LocationStack.size();
     } else
       LocationStack.push_back(L);

     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());
 }
	//===- 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/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);

	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, {}, 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 (llvm::binary_search(CommonArgExpansions, 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, {});
	}

	/// A helper function to check if the current ranges are all inside the same
	/// macro argument expansion as Loc.
	static bool
	rangesInsideSameMacroArgExpansion(FullSourceLoc Loc,
	ArrayRef<CharSourceRange> Ranges) {
	assert(Loc.isMacroID() && "Must be a macro expansion!");

	SmallVector<CharSourceRange> SpellingRanges;
	mapDiagnosticRanges(Loc, Ranges, SpellingRanges);

	unsigned ValidCount =
	llvm::count_if(Ranges, [](const auto &R) { return R.isValid(); });
	if (ValidCount > SpellingRanges.size())
	return false;

	const SourceManager &SM = Loc.getManager();
	for (const auto &R : Ranges) {
	// All positions in the range need to point to Loc.
	SourceLocation Begin = R.getBegin();
	if (Begin == R.getEnd()) {
	if (!SM.isMacroArgExpansion(Begin))
	return false;
	continue;
	}

	while (Begin != R.getEnd()) {
	SourceLocation MacroLoc;
	if (!SM.isMacroArgExpansion(Begin, &MacroLoc))
	return false;
	if (MacroLoc != Loc)
	return false;

	Begin = Begin.getLocWithOffset(1);
	}
	}

	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());

	if (rangesInsideSameMacroArgExpansion(FullSourceLoc(L, SM), Ranges))
	IgnoredEnd = LocationStack.size();
	} else
	LocationStack.push_back(L);

	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());
	}