clang/lib/Frontend/DiagnosticRenderer.cpp

   1 //===- DiagnosticRenderer.cpp - Diagnostic Pretty-Printing ----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "clang/Frontend/DiagnosticRenderer.h"
  10 #include "clang/Basic/Diagnostic.h"
  11 #include "clang/Basic/DiagnosticOptions.h"
  12 #include "clang/Basic/LLVM.h"
  13 #include "clang/Basic/SourceLocation.h"
  14 #include "clang/Basic/SourceManager.h"
  15 #include "clang/Edit/Commit.h"
  16 #include "clang/Edit/EditedSource.h"
  17 #include "clang/Edit/EditsReceiver.h"
  18 #include "clang/Lex/Lexer.h"
  19 #include "llvm/ADT/ArrayRef.h"
  20 #include "llvm/ADT/DenseMap.h"
  21 #include "llvm/ADT/SmallString.h"
  22 #include "llvm/ADT/SmallVector.h"
  23 #include "llvm/ADT/StringRef.h"
  24 #include "llvm/Support/raw_ostream.h"
  25 #include <algorithm>
  26 #include <cassert>
  27 #include <iterator>
  28 #include <utility>
  29
  30 using namespace clang;
  31
  32 DiagnosticRenderer::DiagnosticRenderer(const LangOptions &LangOpts,
  33                                        DiagnosticOptions *DiagOpts)
  34     : LangOpts(LangOpts), DiagOpts(DiagOpts), LastLevel() {}
  35
  36 DiagnosticRenderer::~DiagnosticRenderer() = default;
  37
  38 namespace {
  39
  40 class FixitReceiver : public edit::EditsReceiver {
  41   SmallVectorImpl<FixItHint> &MergedFixits;
  42
  43 public:
  44   FixitReceiver(SmallVectorImpl<FixItHint> &MergedFixits)
  45       : MergedFixits(MergedFixits) {}
  46
  47   void insert(SourceLocation loc, StringRef text) override {
  48     MergedFixits.push_back(FixItHint::CreateInsertion(loc, text));
  49   }
  50
  51   void replace(CharSourceRange range, StringRef text) override {
  52     MergedFixits.push_back(FixItHint::CreateReplacement(range, text));
  53   }
  54 };
  55
  56 } // namespace
  57
  58 static void mergeFixits(ArrayRef<FixItHint> FixItHints,
  59                         const SourceManager &SM, const LangOptions &LangOpts,
  60                         SmallVectorImpl<FixItHint> &MergedFixits) {
  61   edit::Commit commit(SM, LangOpts);
  62   for (const auto &Hint : FixItHints)
  63     if (Hint.CodeToInsert.empty()) {
  64       if (Hint.InsertFromRange.isValid())
  65         commit.insertFromRange(Hint.RemoveRange.getBegin(),
  66                            Hint.InsertFromRange, /*afterToken=*/false,
  67                            Hint.BeforePreviousInsertions);
  68       else
  69         commit.remove(Hint.RemoveRange);
  70     } else {
  71       if (Hint.RemoveRange.isTokenRange() ||
  72           Hint.RemoveRange.getBegin() != Hint.RemoveRange.getEnd())
  73         commit.replace(Hint.RemoveRange, Hint.CodeToInsert);
  74       else
  75         commit.insert(Hint.RemoveRange.getBegin(), Hint.CodeToInsert,
  76                     /*afterToken=*/false, Hint.BeforePreviousInsertions);
  77     }
  78
  79   edit::EditedSource Editor(SM, LangOpts);
  80   if (Editor.commit(commit)) {
  81     FixitReceiver Rec(MergedFixits);
  82     Editor.applyRewrites(Rec);
  83   }
  84 }
  85
  86 void DiagnosticRenderer::emitDiagnostic(FullSourceLoc Loc,
  87                                         DiagnosticsEngine::Level Level,
  88                                         StringRef Message,
  89                                         ArrayRef<CharSourceRange> Ranges,
  90                                         ArrayRef<FixItHint> FixItHints,
  91                                         DiagOrStoredDiag D) {
  92   assert(Loc.hasManager() || Loc.isInvalid());
  93
  94   beginDiagnostic(D, Level);
  95
  96   if (!Loc.isValid())
  97     // If we have no source location, just emit the diagnostic message.
  98     emitDiagnosticMessage(Loc, PresumedLoc(), Level, Message, Ranges, D);
  99   else {
 100     // Get the ranges into a local array we can hack on.
 101     SmallVector<CharSourceRange, 20> MutableRanges(Ranges);
 102
 103     SmallVector<FixItHint, 8> MergedFixits;
 104     if (!FixItHints.empty()) {
 105       mergeFixits(FixItHints, Loc.getManager(), LangOpts, MergedFixits);
 106       FixItHints = MergedFixits;
 107     }
 108
 109     for (const auto &Hint : FixItHints)
 110       if (Hint.RemoveRange.isValid())
 111         MutableRanges.push_back(Hint.RemoveRange);
 112
 113     FullSourceLoc UnexpandedLoc = Loc;
 114
 115     // Find the ultimate expansion location for the diagnostic.
 116     Loc = Loc.getFileLoc();
 117
 118     PresumedLoc PLoc = Loc.getPresumedLoc(DiagOpts->ShowPresumedLoc);
 119
 120     // First, if this diagnostic is not in the main file, print out the
 121     // "included from" lines.
 122     emitIncludeStack(Loc, PLoc, Level);
 123
 124     // Next, emit the actual diagnostic message and caret.
 125     emitDiagnosticMessage(Loc, PLoc, Level, Message, Ranges, D);
 126     emitCaret(Loc, Level, MutableRanges, FixItHints);
 127
 128     // If this location is within a macro, walk from UnexpandedLoc up to Loc
 129     // and produce a macro backtrace.
 130     if (UnexpandedLoc.isValid() && UnexpandedLoc.isMacroID()) {
 131       emitMacroExpansions(UnexpandedLoc, Level, MutableRanges, FixItHints);
 132     }
 133   }
 134
 135   LastLoc = Loc;
 136   LastLevel = Level;
 137
 138   endDiagnostic(D, Level);
 139 }
 140
 141 void DiagnosticRenderer::emitStoredDiagnostic(StoredDiagnostic &Diag) {
 142   emitDiagnostic(Diag.getLocation(), Diag.getLevel(), Diag.getMessage(),
 143                  Diag.getRanges(), Diag.getFixIts(),
 144                  &Diag);
 145 }
 146
 147 void DiagnosticRenderer::emitBasicNote(StringRef Message) {
 148   emitDiagnosticMessage(FullSourceLoc(), PresumedLoc(), DiagnosticsEngine::Note,
 149                         Message, {}, DiagOrStoredDiag());
 150 }
 151
 152 /// Prints an include stack when appropriate for a particular
 153 /// diagnostic level and location.
 154 ///
 155 /// This routine handles all the logic of suppressing particular include
 156 /// stacks (such as those for notes) and duplicate include stacks when
 157 /// repeated warnings occur within the same file. It also handles the logic
 158 /// of customizing the formatting and display of the include stack.
 159 ///
 160 /// \param Loc   The diagnostic location.
 161 /// \param PLoc  The presumed location of the diagnostic location.
 162 /// \param Level The diagnostic level of the message this stack pertains to.
 163 void DiagnosticRenderer::emitIncludeStack(FullSourceLoc Loc, PresumedLoc PLoc,
 164                                           DiagnosticsEngine::Level Level) {
 165   FullSourceLoc IncludeLoc =
 166       PLoc.isInvalid() ? FullSourceLoc()
 167                        : FullSourceLoc(PLoc.getIncludeLoc(), Loc.getManager());
 168
 169   // Skip redundant include stacks altogether.
 170   if (LastIncludeLoc == IncludeLoc)
 171     return;
 172
 173   LastIncludeLoc = IncludeLoc;
 174
 175   if (!DiagOpts->ShowNoteIncludeStack && Level == DiagnosticsEngine::Note)
 176     return;
 177
 178   if (IncludeLoc.isValid())
 179     emitIncludeStackRecursively(IncludeLoc);
 180   else {
 181     emitModuleBuildStack(Loc.getManager());
 182     emitImportStack(Loc);
 183   }
 184 }
 185
 186 /// Helper to recursively walk up the include stack and print each layer
 187 /// on the way back down.
 188 void DiagnosticRenderer::emitIncludeStackRecursively(FullSourceLoc Loc) {
 189   if (Loc.isInvalid()) {
 190     emitModuleBuildStack(Loc.getManager());
 191     return;
 192   }
 193
 194   PresumedLoc PLoc = Loc.getPresumedLoc(DiagOpts->ShowPresumedLoc);
 195   if (PLoc.isInvalid())
 196     return;
 197
 198   // If this source location was imported from a module, print the module
 199   // import stack rather than the
 200   // FIXME: We want submodule granularity here.
 201   std::pair<FullSourceLoc, StringRef> Imported = Loc.getModuleImportLoc();
 202   if (!Imported.second.empty()) {
 203     // This location was imported by a module. Emit the module import stack.
 204     emitImportStackRecursively(Imported.first, Imported.second);
 205     return;
 206   }
 207
 208   // Emit the other include frames first.
 209   emitIncludeStackRecursively(
 210       FullSourceLoc(PLoc.getIncludeLoc(), Loc.getManager()));
 211
 212   // Emit the inclusion text/note.
 213   emitIncludeLocation(Loc, PLoc);
 214 }
 215
 216 /// Emit the module import stack associated with the current location.
 217 void DiagnosticRenderer::emitImportStack(FullSourceLoc Loc) {
 218   if (Loc.isInvalid()) {
 219     emitModuleBuildStack(Loc.getManager());
 220     return;
 221   }
 222
 223   std::pair<FullSourceLoc, StringRef> NextImportLoc = Loc.getModuleImportLoc();
 224   emitImportStackRecursively(NextImportLoc.first, NextImportLoc.second);
 225 }
 226
 227 /// Helper to recursively walk up the import stack and print each layer
 228 /// on the way back down.
 229 void DiagnosticRenderer::emitImportStackRecursively(FullSourceLoc Loc,
 230                                                     StringRef ModuleName) {
 231   if (ModuleName.empty()) {
 232     return;
 233   }
 234
 235   PresumedLoc PLoc = Loc.getPresumedLoc(DiagOpts->ShowPresumedLoc);
 236
 237   // Emit the other import frames first.
 238   std::pair<FullSourceLoc, StringRef> NextImportLoc = Loc.getModuleImportLoc();
 239   emitImportStackRecursively(NextImportLoc.first, NextImportLoc.second);
 240
 241   // Emit the inclusion text/note.
 242   emitImportLocation(Loc, PLoc, ModuleName);
 243 }
 244
 245 /// Emit the module build stack, for cases where a module is (re-)built
 246 /// on demand.
 247 void DiagnosticRenderer::emitModuleBuildStack(const SourceManager &SM) {
 248   ModuleBuildStack Stack = SM.getModuleBuildStack();
 249   for (const auto &I : Stack) {
 250     emitBuildingModuleLocation(I.second, I.second.getPresumedLoc(
 251                                               DiagOpts->ShowPresumedLoc),
 252                                I.first);
 253   }
 254 }
 255
 256 /// A recursive function to trace all possible backtrace locations
 257 /// to match the \p CaretLocFileID.
 258 static SourceLocation
 259 retrieveMacroLocation(SourceLocation Loc, FileID MacroFileID,
 260                       FileID CaretFileID,
 261                       const SmallVectorImpl<FileID> &CommonArgExpansions,
 262                       bool IsBegin, const SourceManager *SM,
 263                       bool &IsTokenRange) {
 264   assert(SM->getFileID(Loc) == MacroFileID);
 265   if (MacroFileID == CaretFileID)
 266     return Loc;
 267   if (!Loc.isMacroID())
 268     return {};
 269
 270   CharSourceRange MacroRange, MacroArgRange;
 271
 272   if (SM->isMacroArgExpansion(Loc)) {
 273     // Only look at the immediate spelling location of this macro argument if
 274     // the other location in the source range is also present in that expansion.
 275     if (std::binary_search(CommonArgExpansions.begin(),
 276                            CommonArgExpansions.end(), MacroFileID))
 277       MacroRange =
 278           CharSourceRange(SM->getImmediateSpellingLoc(Loc), IsTokenRange);
 279     MacroArgRange = SM->getImmediateExpansionRange(Loc);
 280   } else {
 281     MacroRange = SM->getImmediateExpansionRange(Loc);
 282     MacroArgRange =
 283         CharSourceRange(SM->getImmediateSpellingLoc(Loc), IsTokenRange);
 284   }
 285
 286   SourceLocation MacroLocation =
 287       IsBegin ? MacroRange.getBegin() : MacroRange.getEnd();
 288   if (MacroLocation.isValid()) {
 289     MacroFileID = SM->getFileID(MacroLocation);
 290     bool TokenRange = IsBegin ? IsTokenRange : MacroRange.isTokenRange();
 291     MacroLocation =
 292         retrieveMacroLocation(MacroLocation, MacroFileID, CaretFileID,
 293                               CommonArgExpansions, IsBegin, SM, TokenRange);
 294     if (MacroLocation.isValid()) {
 295       IsTokenRange = TokenRange;
 296       return MacroLocation;
 297     }
 298   }
 299
 300   // If we moved the end of the range to an expansion location, we now have
 301   // a range of the same kind as the expansion range.
 302   if (!IsBegin)
 303     IsTokenRange = MacroArgRange.isTokenRange();
 304
 305   SourceLocation MacroArgLocation =
 306       IsBegin ? MacroArgRange.getBegin() : MacroArgRange.getEnd();
 307   MacroFileID = SM->getFileID(MacroArgLocation);
 308   return retrieveMacroLocation(MacroArgLocation, MacroFileID, CaretFileID,
 309                                CommonArgExpansions, IsBegin, SM, IsTokenRange);
 310 }
 311
 312 /// Walk up the chain of macro expansions and collect the FileIDs identifying the
 313 /// expansions.
 314 static void getMacroArgExpansionFileIDs(SourceLocation Loc,
 315                                         SmallVectorImpl<FileID> &IDs,
 316                                         bool IsBegin, const SourceManager *SM) {
 317   while (Loc.isMacroID()) {
 318     if (SM->isMacroArgExpansion(Loc)) {
 319       IDs.push_back(SM->getFileID(Loc));
 320       Loc = SM->getImmediateSpellingLoc(Loc);
 321     } else {
 322       auto ExpRange = SM->getImmediateExpansionRange(Loc);
 323       Loc = IsBegin ? ExpRange.getBegin() : ExpRange.getEnd();
 324     }
 325   }
 326 }
 327
 328 /// Collect the expansions of the begin and end locations and compute the set
 329 /// intersection. Produces a sorted vector of FileIDs in CommonArgExpansions.
 330 static void computeCommonMacroArgExpansionFileIDs(
 331     SourceLocation Begin, SourceLocation End, const SourceManager *SM,
 332     SmallVectorImpl<FileID> &CommonArgExpansions) {
 333   SmallVector<FileID, 4> BeginArgExpansions;
 334   SmallVector<FileID, 4> EndArgExpansions;
 335   getMacroArgExpansionFileIDs(Begin, BeginArgExpansions, /*IsBegin=*/true, SM);
 336   getMacroArgExpansionFileIDs(End, EndArgExpansions, /*IsBegin=*/false, SM);
 337   llvm::sort(BeginArgExpansions);
 338   llvm::sort(EndArgExpansions);
 339   std::set_intersection(BeginArgExpansions.begin(), BeginArgExpansions.end(),
 340                         EndArgExpansions.begin(), EndArgExpansions.end(),
 341                         std::back_inserter(CommonArgExpansions));
 342 }
 343
 344 // Helper function to fix up source ranges.  It takes in an array of ranges,
 345 // and outputs an array of ranges where we want to draw the range highlighting
 346 // around the location specified by CaretLoc.
 347 //
 348 // To find locations which correspond to the caret, we crawl the macro caller
 349 // chain for the beginning and end of each range.  If the caret location
 350 // is in a macro expansion, we search each chain for a location
 351 // in the same expansion as the caret; otherwise, we crawl to the top of
 352 // each chain. Two locations are part of the same macro expansion
 353 // iff the FileID is the same.
 354 static void
 355 mapDiagnosticRanges(FullSourceLoc CaretLoc, ArrayRef<CharSourceRange> Ranges,
 356                     SmallVectorImpl<CharSourceRange> &SpellingRanges) {
 357   FileID CaretLocFileID = CaretLoc.getFileID();
 358
 359   const SourceManager *SM = &CaretLoc.getManager();
 360
 361   for (const auto &Range : Ranges) {
 362     if (Range.isInvalid())
 363       continue;
 364
 365     SourceLocation Begin = Range.getBegin(), End = Range.getEnd();
 366     bool IsTokenRange = Range.isTokenRange();
 367
 368     FileID BeginFileID = SM->getFileID(Begin);
 369     FileID EndFileID = SM->getFileID(End);
 370
 371     // Find the common parent for the beginning and end of the range.
 372
 373     // First, crawl the expansion chain for the beginning of the range.
 374     llvm::SmallDenseMap<FileID, SourceLocation> BeginLocsMap;
 375     while (Begin.isMacroID() && BeginFileID != EndFileID) {
 376       BeginLocsMap[BeginFileID] = Begin;
 377       Begin = SM->getImmediateExpansionRange(Begin).getBegin();
 378       BeginFileID = SM->getFileID(Begin);
 379     }
 380
 381     // Then, crawl the expansion chain for the end of the range.
 382     if (BeginFileID != EndFileID) {
 383       while (End.isMacroID() && !BeginLocsMap.count(EndFileID)) {
 384         auto Exp = SM->getImmediateExpansionRange(End);
 385         IsTokenRange = Exp.isTokenRange();
 386         End = Exp.getEnd();
 387         EndFileID = SM->getFileID(End);
 388       }
 389       if (End.isMacroID()) {
 390         Begin = BeginLocsMap[EndFileID];
 391         BeginFileID = EndFileID;
 392       }
 393     }
 394
 395     // There is a chance that begin or end is invalid here, for example if
 396     // specific compile error is reported.
 397     // It is possible that the FileID's do not match, if one comes from an
 398     // included file. In this case we can not produce a meaningful source range.
 399     if (Begin.isInvalid() || End.isInvalid() || BeginFileID != EndFileID)
 400       continue;
 401
 402     // Do the backtracking.
 403     SmallVector<FileID, 4> CommonArgExpansions;
 404     computeCommonMacroArgExpansionFileIDs(Begin, End, SM, CommonArgExpansions);
 405     Begin = retrieveMacroLocation(Begin, BeginFileID, CaretLocFileID,
 406                                   CommonArgExpansions, /*IsBegin=*/true, SM,
 407                                   IsTokenRange);
 408     End = retrieveMacroLocation(End, BeginFileID, CaretLocFileID,
 409                                 CommonArgExpansions, /*IsBegin=*/false, SM,
 410                                 IsTokenRange);
 411     if (Begin.isInvalid() || End.isInvalid()) continue;
 412
 413     // Return the spelling location of the beginning and end of the range.
 414     Begin = SM->getSpellingLoc(Begin);
 415     End = SM->getSpellingLoc(End);
 416
 417     SpellingRanges.push_back(CharSourceRange(SourceRange(Begin, End),
 418                                              IsTokenRange));
 419   }
 420 }
 421
 422 void DiagnosticRenderer::emitCaret(FullSourceLoc Loc,
 423                                    DiagnosticsEngine::Level Level,
 424                                    ArrayRef<CharSourceRange> Ranges,
 425                                    ArrayRef<FixItHint> Hints) {
 426   SmallVector<CharSourceRange, 4> SpellingRanges;
 427   mapDiagnosticRanges(Loc, Ranges, SpellingRanges);
 428   emitCodeContext(Loc, Level, SpellingRanges, Hints);
 429 }
 430
 431 /// A helper function for emitMacroExpansion to print the
 432 /// macro expansion message
 433 void DiagnosticRenderer::emitSingleMacroExpansion(
 434     FullSourceLoc Loc, DiagnosticsEngine::Level Level,
 435     ArrayRef<CharSourceRange> Ranges) {
 436   // Find the spelling location for the macro definition. We must use the
 437   // spelling location here to avoid emitting a macro backtrace for the note.
 438   FullSourceLoc SpellingLoc = Loc.getSpellingLoc();
 439
 440   // Map the ranges into the FileID of the diagnostic location.
 441   SmallVector<CharSourceRange, 4> SpellingRanges;
 442   mapDiagnosticRanges(Loc, Ranges, SpellingRanges);
 443
 444   SmallString<100> MessageStorage;
 445   llvm::raw_svector_ostream Message(MessageStorage);
 446   StringRef MacroName = Lexer::getImmediateMacroNameForDiagnostics(
 447       Loc, Loc.getManager(), LangOpts);
 448   if (MacroName.empty())
 449     Message << "expanded from here";
 450   else
 451     Message << "expanded from macro '" << MacroName << "'";
 452
 453   emitDiagnostic(SpellingLoc, DiagnosticsEngine::Note, Message.str(),
 454                  SpellingRanges, {});
 455 }
 456
 457 /// Check that the macro argument location of Loc starts with ArgumentLoc.
 458 /// The starting location of the macro expansions is used to differeniate
 459 /// different macro expansions.
 460 static bool checkLocForMacroArgExpansion(SourceLocation Loc,
 461                                          const SourceManager &SM,
 462                                          SourceLocation ArgumentLoc) {
 463   SourceLocation MacroLoc;
 464   if (SM.isMacroArgExpansion(Loc, &MacroLoc)) {
 465     if (ArgumentLoc == MacroLoc) return true;
 466   }
 467
 468   return false;
 469 }
 470
 471 /// Check if all the locations in the range have the same macro argument
 472 /// expansion, and that the expansion starts with ArgumentLoc.
 473 static bool checkRangeForMacroArgExpansion(CharSourceRange Range,
 474                                            const SourceManager &SM,
 475                                            SourceLocation ArgumentLoc) {
 476   SourceLocation BegLoc = Range.getBegin(), EndLoc = Range.getEnd();
 477   while (BegLoc != EndLoc) {
 478     if (!checkLocForMacroArgExpansion(BegLoc, SM, ArgumentLoc))
 479       return false;
 480     BegLoc.getLocWithOffset(1);
 481   }
 482
 483   return checkLocForMacroArgExpansion(BegLoc, SM, ArgumentLoc);
 484 }
 485
 486 /// A helper function to check if the current ranges are all inside the same
 487 /// macro argument expansion as Loc.
 488 static bool checkRangesForMacroArgExpansion(FullSourceLoc Loc,
 489                                             ArrayRef<CharSourceRange> Ranges) {
 490   assert(Loc.isMacroID() && "Must be a macro expansion!");
 491
 492   SmallVector<CharSourceRange, 4> SpellingRanges;
 493   mapDiagnosticRanges(Loc, Ranges, SpellingRanges);
 494
 495   // Count all valid ranges.
 496   unsigned ValidCount =
 497       llvm::count_if(Ranges, [](const auto &R) { return R.isValid(); });
 498
 499   if (ValidCount > SpellingRanges.size())
 500     return false;
 501
 502   // To store the source location of the argument location.
 503   FullSourceLoc ArgumentLoc;
 504
 505   // Set the ArgumentLoc to the beginning location of the expansion of Loc
 506   // so to check if the ranges expands to the same beginning location.
 507   if (!Loc.isMacroArgExpansion(&ArgumentLoc))
 508     return false;
 509
 510   for (const auto &Range : SpellingRanges)
 511     if (!checkRangeForMacroArgExpansion(Range, Loc.getManager(), ArgumentLoc))
 512       return false;
 513
 514   return true;
 515 }
 516
 517 /// Recursively emit notes for each macro expansion and caret
 518 /// diagnostics where appropriate.
 519 ///
 520 /// Walks up the macro expansion stack printing expansion notes, the code
 521 /// snippet, caret, underlines and FixItHint display as appropriate at each
 522 /// level.
 523 ///
 524 /// \param Loc The location for this caret.
 525 /// \param Level The diagnostic level currently being emitted.
 526 /// \param Ranges The underlined ranges for this code snippet.
 527 /// \param Hints The FixIt hints active for this diagnostic.
 528 void DiagnosticRenderer::emitMacroExpansions(FullSourceLoc Loc,
 529                                              DiagnosticsEngine::Level Level,
 530                                              ArrayRef<CharSourceRange> Ranges,
 531                                              ArrayRef<FixItHint> Hints) {
 532   assert(Loc.isValid() && "must have a valid source location here");
 533   const SourceManager &SM = Loc.getManager();
 534   SourceLocation L = Loc;
 535
 536   // Produce a stack of macro backtraces.
 537   SmallVector<SourceLocation, 8> LocationStack;
 538   unsigned IgnoredEnd = 0;
 539   while (L.isMacroID()) {
 540     // If this is the expansion of a macro argument, point the caret at the
 541     // use of the argument in the definition of the macro, not the expansion.
 542     if (SM.isMacroArgExpansion(L))
 543       LocationStack.push_back(SM.getImmediateExpansionRange(L).getBegin());
 544     else
 545       LocationStack.push_back(L);
 546
 547     if (checkRangesForMacroArgExpansion(FullSourceLoc(L, SM), Ranges))
 548       IgnoredEnd = LocationStack.size();
 549
 550     L = SM.getImmediateMacroCallerLoc(L);
 551
 552     // Once the location no longer points into a macro, try stepping through
 553     // the last found location.  This sometimes produces additional useful
 554     // backtraces.
 555     if (L.isFileID())
 556       L = SM.getImmediateMacroCallerLoc(LocationStack.back());
 557     assert(L.isValid() && "must have a valid source location here");
 558   }
 559
 560   LocationStack.erase(LocationStack.begin(),
 561                       LocationStack.begin() + IgnoredEnd);
 562
 563   unsigned MacroDepth = LocationStack.size();
 564   unsigned MacroLimit = DiagOpts->MacroBacktraceLimit;
 565   if (MacroDepth <= MacroLimit || MacroLimit == 0) {
 566     for (auto I = LocationStack.rbegin(), E = LocationStack.rend();
 567          I != E; ++I)
 568       emitSingleMacroExpansion(FullSourceLoc(*I, SM), Level, Ranges);
 569     return;
 570   }
 571
 572   unsigned MacroStartMessages = MacroLimit / 2;
 573   unsigned MacroEndMessages = MacroLimit / 2 + MacroLimit % 2;
 574
 575   for (auto I = LocationStack.rbegin(),
 576             E = LocationStack.rbegin() + MacroStartMessages;
 577        I != E; ++I)
 578     emitSingleMacroExpansion(FullSourceLoc(*I, SM), Level, Ranges);
 579
 580   SmallString<200> MessageStorage;
 581   llvm::raw_svector_ostream Message(MessageStorage);
 582   Message << "(skipping " << (MacroDepth - MacroLimit)
 583           << " expansions in backtrace; use -fmacro-backtrace-limit=0 to "
 584              "see all)";
 585   emitBasicNote(Message.str());
 586
 587   for (auto I = LocationStack.rend() - MacroEndMessages,
 588             E = LocationStack.rend();
 589        I != E; ++I)
 590     emitSingleMacroExpansion(FullSourceLoc(*I, SM), Level, Ranges);
 591 }
 592
 593 DiagnosticNoteRenderer::~DiagnosticNoteRenderer() = default;
 594
 595 void DiagnosticNoteRenderer::emitIncludeLocation(FullSourceLoc Loc,
 596                                                  PresumedLoc PLoc) {
 597   // Generate a note indicating the include location.
 598   SmallString<200> MessageStorage;
 599   llvm::raw_svector_ostream Message(MessageStorage);
 600   Message << "in file included from " << PLoc.getFilename() << ':'
 601           << PLoc.getLine() << ":";
 602   emitNote(Loc, Message.str());
 603 }
 604
 605 void DiagnosticNoteRenderer::emitImportLocation(FullSourceLoc Loc,
 606                                                 PresumedLoc PLoc,
 607                                                 StringRef ModuleName) {
 608   // Generate a note indicating the include location.
 609   SmallString<200> MessageStorage;
 610   llvm::raw_svector_ostream Message(MessageStorage);
 611   Message << "in module '" << ModuleName;
 612   if (PLoc.isValid())
 613     Message << "' imported from " << PLoc.getFilename() << ':'
 614             << PLoc.getLine();
 615   Message << ":";
 616   emitNote(Loc, Message.str());
 617 }
 618
 619 void DiagnosticNoteRenderer::emitBuildingModuleLocation(FullSourceLoc Loc,
 620                                                         PresumedLoc PLoc,
 621                                                         StringRef ModuleName) {
 622   // Generate a note indicating the include location.
 623   SmallString<200> MessageStorage;
 624   llvm::raw_svector_ostream Message(MessageStorage);
 625   if (PLoc.isValid())
 626     Message << "while building module '" << ModuleName << "' imported from "
 627             << PLoc.getFilename() << ':' << PLoc.getLine() << ":";
 628   else
 629     Message << "while building module '" << ModuleName << "':";
 630   emitNote(Loc, Message.str());
 631 }