clang-tools-extra/clangd/Diagnostics.cpp

   1 //===--- Diagnostics.cpp -----------------------------------------*- C++-*-===//
   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 "Diagnostics.h"
  10 #include "../clang-tidy/ClangTidyDiagnosticConsumer.h"
  11 #include "Compiler.h"
  12 #include "Protocol.h"
  13 #include "SourceCode.h"
  14 #include "support/Logger.h"
  15 #include "clang/Basic/AllDiagnostics.h" // IWYU pragma: keep
  16 #include "clang/Basic/Diagnostic.h"
  17 #include "clang/Basic/DiagnosticIDs.h"
  18 #include "clang/Basic/LLVM.h"
  19 #include "clang/Basic/SourceLocation.h"
  20 #include "clang/Basic/SourceManager.h"
  21 #include "clang/Basic/TokenKinds.h"
  22 #include "clang/Lex/Lexer.h"
  23 #include "clang/Lex/Token.h"
  24 #include "llvm/ADT/ArrayRef.h"
  25 #include "llvm/ADT/DenseSet.h"
  26 #include "llvm/ADT/STLExtras.h"
  27 #include "llvm/ADT/STLFunctionalExtras.h"
  28 #include "llvm/ADT/ScopeExit.h"
  29 #include "llvm/ADT/SmallString.h"
  30 #include "llvm/ADT/SmallVector.h"
  31 #include "llvm/ADT/StringExtras.h"
  32 #include "llvm/ADT/StringRef.h"
  33 #include "llvm/ADT/StringSet.h"
  34 #include "llvm/ADT/Twine.h"
  35 #include "llvm/Support/ErrorHandling.h"
  36 #include "llvm/Support/FormatVariadic.h"
  37 #include "llvm/Support/Path.h"
  38 #include "llvm/Support/SourceMgr.h"
  39 #include "llvm/Support/raw_ostream.h"
  40 #include <algorithm>
  41 #include <cassert>
  42 #include <optional>
  43 #include <set>
  44 #include <string>
  45 #include <tuple>
  46 #include <utility>
  47 #include <vector>
  48
  49 namespace clang {
  50 namespace clangd {
  51 namespace {
  52
  53 const char *getDiagnosticCode(unsigned ID) {
  54   switch (ID) {
  55 #define DIAG(ENUM, CLASS, DEFAULT_MAPPING, DESC, GROPU, SFINAE, NOWERROR,      \
  56              SHOWINSYSHEADER, SHOWINSYSMACRO, DEFERRABLE, CATEGORY)            \
  57   case clang::diag::ENUM:                                                      \
  58     return #ENUM;
  59 #include "clang/Basic/DiagnosticASTKinds.inc"
  60 #include "clang/Basic/DiagnosticAnalysisKinds.inc"
  61 #include "clang/Basic/DiagnosticCommentKinds.inc"
  62 #include "clang/Basic/DiagnosticCommonKinds.inc"
  63 #include "clang/Basic/DiagnosticDriverKinds.inc"
  64 #include "clang/Basic/DiagnosticFrontendKinds.inc"
  65 #include "clang/Basic/DiagnosticLexKinds.inc"
  66 #include "clang/Basic/DiagnosticParseKinds.inc"
  67 #include "clang/Basic/DiagnosticRefactoringKinds.inc"
  68 #include "clang/Basic/DiagnosticSemaKinds.inc"
  69 #include "clang/Basic/DiagnosticSerializationKinds.inc"
  70 #undef DIAG
  71   default:
  72     return nullptr;
  73   }
  74 }
  75
  76 bool mentionsMainFile(const Diag &D) {
  77   if (D.InsideMainFile)
  78     return true;
  79   // Fixes are always in the main file.
  80   if (!D.Fixes.empty())
  81     return true;
  82   for (auto &N : D.Notes) {
  83     if (N.InsideMainFile)
  84       return true;
  85   }
  86   return false;
  87 }
  88
  89 bool isExcluded(unsigned DiagID) {
  90   // clang will always fail parsing MS ASM, we don't link in desc + asm parser.
  91   if (DiagID == clang::diag::err_msasm_unable_to_create_target ||
  92       DiagID == clang::diag::err_msasm_unsupported_arch)
  93     return true;
  94   return false;
  95 }
  96
  97 // Checks whether a location is within a half-open range.
  98 // Note that clang also uses closed source ranges, which this can't handle!
  99 bool locationInRange(SourceLocation L, CharSourceRange R,
 100                      const SourceManager &M) {
 101   assert(R.isCharRange());
 102   if (!R.isValid() || M.getFileID(R.getBegin()) != M.getFileID(R.getEnd()) ||
 103       M.getFileID(R.getBegin()) != M.getFileID(L))
 104     return false;
 105   return L != R.getEnd() && M.isPointWithin(L, R.getBegin(), R.getEnd());
 106 }
 107
 108 // Clang diags have a location (shown as ^) and 0 or more ranges (~~~~).
 109 // LSP needs a single range.
 110 std::optional<Range> diagnosticRange(const clang::Diagnostic &D,
 111                                      const LangOptions &L) {
 112   auto &M = D.getSourceManager();
 113   auto PatchedRange = [&M](CharSourceRange &R) {
 114     R.setBegin(translatePreamblePatchLocation(R.getBegin(), M));
 115     R.setEnd(translatePreamblePatchLocation(R.getEnd(), M));
 116     return R;
 117   };
 118   auto Loc = M.getFileLoc(D.getLocation());
 119   for (const auto &CR : D.getRanges()) {
 120     auto R = Lexer::makeFileCharRange(CR, M, L);
 121     if (locationInRange(Loc, R, M))
 122       return halfOpenToRange(M, PatchedRange(R));
 123   }
 124   // The range may be given as a fixit hint instead.
 125   for (const auto &F : D.getFixItHints()) {
 126     auto R = Lexer::makeFileCharRange(F.RemoveRange, M, L);
 127     if (locationInRange(Loc, R, M))
 128       return halfOpenToRange(M, PatchedRange(R));
 129   }
 130   // Source locations from stale preambles might become OOB.
 131   // FIXME: These diagnostics might point to wrong locations even when they're
 132   // not OOB.
 133   auto [FID, Offset] = M.getDecomposedLoc(Loc);
 134   if (Offset > M.getBufferData(FID).size())
 135     return std::nullopt;
 136   // If the token at the location is not a comment, we use the token.
 137   // If we can't get the token at the location, fall back to using the location
 138   auto R = CharSourceRange::getCharRange(Loc);
 139   Token Tok;
 140   if (!Lexer::getRawToken(Loc, Tok, M, L, true) && Tok.isNot(tok::comment))
 141     R = CharSourceRange::getTokenRange(Tok.getLocation(), Tok.getEndLoc());
 142   return halfOpenToRange(M, PatchedRange(R));
 143 }
 144
 145 // Try to find a location in the main-file to report the diagnostic D.
 146 // Returns a description like "in included file", or nullptr on failure.
 147 const char *getMainFileRange(const Diag &D, const SourceManager &SM,
 148                              SourceLocation DiagLoc, Range &R) {
 149   // Look for a note in the main file indicating template instantiation.
 150   for (const auto &N : D.Notes) {
 151     if (N.InsideMainFile) {
 152       switch (N.ID) {
 153       case diag::note_template_class_instantiation_was_here:
 154       case diag::note_template_class_explicit_specialization_was_here:
 155       case diag::note_template_class_instantiation_here:
 156       case diag::note_template_member_class_here:
 157       case diag::note_template_member_function_here:
 158       case diag::note_function_template_spec_here:
 159       case diag::note_template_static_data_member_def_here:
 160       case diag::note_template_variable_def_here:
 161       case diag::note_template_enum_def_here:
 162       case diag::note_template_nsdmi_here:
 163       case diag::note_template_type_alias_instantiation_here:
 164       case diag::note_template_exception_spec_instantiation_here:
 165       case diag::note_template_requirement_instantiation_here:
 166       case diag::note_evaluating_exception_spec_here:
 167       case diag::note_default_arg_instantiation_here:
 168       case diag::note_default_function_arg_instantiation_here:
 169       case diag::note_explicit_template_arg_substitution_here:
 170       case diag::note_function_template_deduction_instantiation_here:
 171       case diag::note_deduced_template_arg_substitution_here:
 172       case diag::note_prior_template_arg_substitution:
 173       case diag::note_template_default_arg_checking:
 174       case diag::note_concept_specialization_here:
 175       case diag::note_nested_requirement_here:
 176       case diag::note_checking_constraints_for_template_id_here:
 177       case diag::note_checking_constraints_for_var_spec_id_here:
 178       case diag::note_checking_constraints_for_class_spec_id_here:
 179       case diag::note_checking_constraints_for_function_here:
 180       case diag::note_constraint_substitution_here:
 181       case diag::note_constraint_normalization_here:
 182       case diag::note_parameter_mapping_substitution_here:
 183         R = N.Range;
 184         return "in template";
 185       default:
 186         break;
 187       }
 188     }
 189   }
 190   // Look for where the file with the error was #included.
 191   auto GetIncludeLoc = [&SM](SourceLocation SLoc) {
 192     return SM.getIncludeLoc(SM.getFileID(SLoc));
 193   };
 194   for (auto IncludeLocation = GetIncludeLoc(SM.getExpansionLoc(DiagLoc));
 195        IncludeLocation.isValid();
 196        IncludeLocation = GetIncludeLoc(IncludeLocation)) {
 197     if (clangd::isInsideMainFile(IncludeLocation, SM)) {
 198       R.start = sourceLocToPosition(SM, IncludeLocation);
 199       R.end = sourceLocToPosition(
 200           SM,
 201           Lexer::getLocForEndOfToken(IncludeLocation, 0, SM, LangOptions()));
 202       return "in included file";
 203     }
 204   }
 205   return nullptr;
 206 }
 207
 208 // Place the diagnostic the main file, rather than the header, if possible:
 209 //   - for errors in included files, use the #include location
 210 //   - for errors in template instantiation, use the instantiation location
 211 // In both cases, add the original header location as a note.
 212 bool tryMoveToMainFile(Diag &D, FullSourceLoc DiagLoc) {
 213   const SourceManager &SM = DiagLoc.getManager();
 214   DiagLoc = DiagLoc.getExpansionLoc();
 215   Range R;
 216   const char *Prefix = getMainFileRange(D, SM, DiagLoc, R);
 217   if (!Prefix)
 218     return false;
 219
 220   // Add a note that will point to real diagnostic.
 221   auto FE = *SM.getFileEntryRefForID(SM.getFileID(DiagLoc));
 222   D.Notes.emplace(D.Notes.begin());
 223   Note &N = D.Notes.front();
 224   N.AbsFile = std::string(FE.getFileEntry().tryGetRealPathName());
 225   N.File = std::string(FE.getName());
 226   N.Message = "error occurred here";
 227   N.Range = D.Range;
 228
 229   // Update diag to point at include inside main file.
 230   D.File = SM.getFileEntryRefForID(SM.getMainFileID())->getName().str();
 231   D.Range = std::move(R);
 232   D.InsideMainFile = true;
 233   // Update message to mention original file.
 234   D.Message = llvm::formatv("{0}: {1}", Prefix, D.Message);
 235   return true;
 236 }
 237
 238 bool isNote(DiagnosticsEngine::Level L) {
 239   return L == DiagnosticsEngine::Note || L == DiagnosticsEngine::Remark;
 240 }
 241
 242 llvm::StringRef diagLeveltoString(DiagnosticsEngine::Level Lvl) {
 243   switch (Lvl) {
 244   case DiagnosticsEngine::Ignored:
 245     return "ignored";
 246   case DiagnosticsEngine::Note:
 247     return "note";
 248   case DiagnosticsEngine::Remark:
 249     return "remark";
 250   case DiagnosticsEngine::Warning:
 251     return "warning";
 252   case DiagnosticsEngine::Error:
 253     return "error";
 254   case DiagnosticsEngine::Fatal:
 255     return "fatal error";
 256   }
 257   llvm_unreachable("unhandled DiagnosticsEngine::Level");
 258 }
 259
 260 /// Prints a single diagnostic in a clang-like manner, the output includes
 261 /// location, severity and error message. An example of the output message is:
 262 ///
 263 ///     main.cpp:12:23: error: undeclared identifier
 264 ///
 265 /// For main file we only print the basename and for all other files we print
 266 /// the filename on a separate line to provide a slightly more readable output
 267 /// in the editors:
 268 ///
 269 ///     dir1/dir2/dir3/../../dir4/header.h:12:23
 270 ///     error: undeclared identifier
 271 void printDiag(llvm::raw_string_ostream &OS, const DiagBase &D) {
 272   if (D.InsideMainFile) {
 273     // Paths to main files are often taken from compile_command.json, where they
 274     // are typically absolute. To reduce noise we print only basename for them,
 275     // it should not be confusing and saves space.
 276     OS << llvm::sys::path::filename(D.File) << ":";
 277   } else {
 278     OS << D.File << ":";
 279   }
 280   // Note +1 to line and character. clangd::Range is zero-based, but when
 281   // printing for users we want one-based indexes.
 282   auto Pos = D.Range.start;
 283   OS << (Pos.line + 1) << ":" << (Pos.character + 1) << ":";
 284   // The non-main-file paths are often too long, putting them on a separate
 285   // line improves readability.
 286   if (D.InsideMainFile)
 287     OS << " ";
 288   else
 289     OS << "\n";
 290   OS << diagLeveltoString(D.Severity) << ": " << D.Message;
 291 }
 292
 293 /// Capitalizes the first word in the diagnostic's message.
 294 std::string capitalize(std::string Message) {
 295   if (!Message.empty())
 296     Message[0] = llvm::toUpper(Message[0]);
 297   return Message;
 298 }
 299
 300 /// Returns a message sent to LSP for the main diagnostic in \p D.
 301 /// This message may include notes, if they're not emitted in some other way.
 302 /// Example output:
 303 ///
 304 ///     no matching function for call to 'foo'
 305 ///
 306 ///     main.cpp:3:5: note: candidate function not viable: requires 2 arguments
 307 ///
 308 ///     dir1/dir2/dir3/../../dir4/header.h:12:23
 309 ///     note: candidate function not viable: requires 3 arguments
 310 std::string mainMessage(const Diag &D, const ClangdDiagnosticOptions &Opts) {
 311   std::string Result;
 312   llvm::raw_string_ostream OS(Result);
 313   OS << D.Message;
 314   if (Opts.DisplayFixesCount && !D.Fixes.empty())
 315     OS << " (" << (D.Fixes.size() > 1 ? "fixes" : "fix") << " available)";
 316   // If notes aren't emitted as structured info, add them to the message.
 317   if (!Opts.EmitRelatedLocations)
 318     for (auto &Note : D.Notes) {
 319       OS << "\n\n";
 320       printDiag(OS, Note);
 321     }
 322   OS.flush();
 323   return capitalize(std::move(Result));
 324 }
 325
 326 /// Returns a message sent to LSP for the note of the main diagnostic.
 327 std::string noteMessage(const Diag &Main, const DiagBase &Note,
 328                         const ClangdDiagnosticOptions &Opts) {
 329   std::string Result;
 330   llvm::raw_string_ostream OS(Result);
 331   OS << Note.Message;
 332   // If the client doesn't support structured links between the note and the
 333   // original diagnostic, then emit the main diagnostic to give context.
 334   if (!Opts.EmitRelatedLocations) {
 335     OS << "\n\n";
 336     printDiag(OS, Main);
 337   }
 338   OS.flush();
 339   return capitalize(std::move(Result));
 340 }
 341
 342 void setTags(clangd::Diag &D) {
 343   static const auto *DeprecatedDiags = new llvm::DenseSet<unsigned>{
 344       diag::warn_access_decl_deprecated,
 345       diag::warn_atl_uuid_deprecated,
 346       diag::warn_deprecated,
 347       diag::warn_deprecated_altivec_src_compat,
 348       diag::warn_deprecated_comma_subscript,
 349       diag::warn_deprecated_copy,
 350       diag::warn_deprecated_copy_with_dtor,
 351       diag::warn_deprecated_copy_with_user_provided_copy,
 352       diag::warn_deprecated_copy_with_user_provided_dtor,
 353       diag::warn_deprecated_def,
 354       diag::warn_deprecated_increment_decrement_volatile,
 355       diag::warn_deprecated_message,
 356       diag::warn_deprecated_redundant_constexpr_static_def,
 357       diag::warn_deprecated_register,
 358       diag::warn_deprecated_simple_assign_volatile,
 359       diag::warn_deprecated_string_literal_conversion,
 360       diag::warn_deprecated_this_capture,
 361       diag::warn_deprecated_volatile_param,
 362       diag::warn_deprecated_volatile_return,
 363       diag::warn_deprecated_volatile_structured_binding,
 364       diag::warn_opencl_attr_deprecated_ignored,
 365       diag::warn_property_method_deprecated,
 366       diag::warn_vector_mode_deprecated,
 367   };
 368   static const auto *UnusedDiags = new llvm::DenseSet<unsigned>{
 369       diag::warn_opencl_attr_deprecated_ignored,
 370       diag::warn_pragma_attribute_unused,
 371       diag::warn_unused_but_set_parameter,
 372       diag::warn_unused_but_set_variable,
 373       diag::warn_unused_comparison,
 374       diag::warn_unused_const_variable,
 375       diag::warn_unused_exception_param,
 376       diag::warn_unused_function,
 377       diag::warn_unused_label,
 378       diag::warn_unused_lambda_capture,
 379       diag::warn_unused_local_typedef,
 380       diag::warn_unused_member_function,
 381       diag::warn_unused_parameter,
 382       diag::warn_unused_private_field,
 383       diag::warn_unused_property_backing_ivar,
 384       diag::warn_unused_template,
 385       diag::warn_unused_variable,
 386   };
 387   if (DeprecatedDiags->contains(D.ID)) {
 388     D.Tags.push_back(DiagnosticTag::Deprecated);
 389   } else if (UnusedDiags->contains(D.ID)) {
 390     D.Tags.push_back(DiagnosticTag::Unnecessary);
 391   }
 392   if (D.Source == Diag::ClangTidy) {
 393     if (llvm::StringRef(D.Name).starts_with("misc-unused-"))
 394       D.Tags.push_back(DiagnosticTag::Unnecessary);
 395     if (llvm::StringRef(D.Name).starts_with("modernize-"))
 396       D.Tags.push_back(DiagnosticTag::Deprecated);
 397   }
 398 }
 399 } // namespace
 400
 401 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const DiagBase &D) {
 402   OS << "[";
 403   if (!D.InsideMainFile)
 404     OS << D.File << ":";
 405   OS << D.Range.start << "-" << D.Range.end << "] ";
 406
 407   return OS << D.Message;
 408 }
 409
 410 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Fix &F) {
 411   OS << F.Message << " {";
 412   const char *Sep = "";
 413   for (const auto &Edit : F.Edits) {
 414     OS << Sep << Edit;
 415     Sep = ", ";
 416   }
 417   return OS << "}";
 418 }
 419
 420 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Diag &D) {
 421   OS << static_cast<const DiagBase &>(D);
 422   if (!D.Notes.empty()) {
 423     OS << ", notes: {";
 424     const char *Sep = "";
 425     for (auto &Note : D.Notes) {
 426       OS << Sep << Note;
 427       Sep = ", ";
 428     }
 429     OS << "}";
 430   }
 431   if (!D.Fixes.empty()) {
 432     OS << ", fixes: {";
 433     const char *Sep = "";
 434     for (auto &Fix : D.Fixes) {
 435       OS << Sep << Fix;
 436       Sep = ", ";
 437     }
 438     OS << "}";
 439   }
 440   return OS;
 441 }
 442
 443 Diag toDiag(const llvm::SMDiagnostic &D, Diag::DiagSource Source) {
 444   Diag Result;
 445   Result.Message = D.getMessage().str();
 446   switch (D.getKind()) {
 447   case llvm::SourceMgr::DK_Error:
 448     Result.Severity = DiagnosticsEngine::Error;
 449     break;
 450   case llvm::SourceMgr::DK_Warning:
 451     Result.Severity = DiagnosticsEngine::Warning;
 452     break;
 453   default:
 454     break;
 455   }
 456   Result.Source = Source;
 457   Result.AbsFile = D.getFilename().str();
 458   Result.InsideMainFile = D.getSourceMgr()->FindBufferContainingLoc(
 459                               D.getLoc()) == D.getSourceMgr()->getMainFileID();
 460   if (D.getRanges().empty())
 461     Result.Range = {{D.getLineNo() - 1, D.getColumnNo()},
 462                     {D.getLineNo() - 1, D.getColumnNo()}};
 463   else
 464     Result.Range = {{D.getLineNo() - 1, (int)D.getRanges().front().first},
 465                     {D.getLineNo() - 1, (int)D.getRanges().front().second}};
 466   return Result;
 467 }
 468
 469 void toLSPDiags(
 470     const Diag &D, const URIForFile &File, const ClangdDiagnosticOptions &Opts,
 471     llvm::function_ref<void(clangd::Diagnostic, llvm::ArrayRef<Fix>)> OutFn) {
 472   clangd::Diagnostic Main;
 473   Main.severity = getSeverity(D.Severity);
 474   // We downgrade severity for certain noisy warnings, like deprecated
 475   // declartions. These already have visible decorations inside the editor and
 476   // most users find the extra clutter in the UI (gutter, minimap, diagnostics
 477   // views) overwhelming.
 478   if (D.Severity == DiagnosticsEngine::Warning) {
 479     if (llvm::is_contained(D.Tags, DiagnosticTag::Deprecated))
 480       Main.severity = getSeverity(DiagnosticsEngine::Remark);
 481   }
 482
 483   // Main diagnostic should always refer to a range inside main file. If a
 484   // diagnostic made it so for, it means either itself or one of its notes is
 485   // inside main file. It's also possible that there's a fix in the main file,
 486   // but we preserve fixes iff primary diagnostic is in the main file.
 487   if (D.InsideMainFile) {
 488     Main.range = D.Range;
 489   } else {
 490     auto It =
 491         llvm::find_if(D.Notes, [](const Note &N) { return N.InsideMainFile; });
 492     assert(It != D.Notes.end() &&
 493            "neither the main diagnostic nor notes are inside main file");
 494     Main.range = It->Range;
 495   }
 496
 497   Main.code = D.Name;
 498   if (auto URI = getDiagnosticDocURI(D.Source, D.ID, D.Name)) {
 499     Main.codeDescription.emplace();
 500     Main.codeDescription->href = std::move(*URI);
 501   }
 502   switch (D.Source) {
 503   case Diag::Clang:
 504     Main.source = "clang";
 505     break;
 506   case Diag::ClangTidy:
 507     Main.source = "clang-tidy";
 508     break;
 509   case Diag::Clangd:
 510     Main.source = "clangd";
 511     break;
 512   case Diag::ClangdConfig:
 513     Main.source = "clangd-config";
 514     break;
 515   case Diag::Unknown:
 516     break;
 517   }
 518   if (Opts.SendDiagnosticCategory && !D.Category.empty())
 519     Main.category = D.Category;
 520
 521   Main.message = mainMessage(D, Opts);
 522   if (Opts.EmitRelatedLocations) {
 523     Main.relatedInformation.emplace();
 524     for (auto &Note : D.Notes) {
 525       if (!Note.AbsFile) {
 526         vlog("Dropping note from unknown file: {0}", Note);
 527         continue;
 528       }
 529       DiagnosticRelatedInformation RelInfo;
 530       RelInfo.location.range = Note.Range;
 531       RelInfo.location.uri =
 532           URIForFile::canonicalize(*Note.AbsFile, File.file());
 533       RelInfo.message = noteMessage(D, Note, Opts);
 534       Main.relatedInformation->push_back(std::move(RelInfo));
 535     }
 536   }
 537   Main.tags = D.Tags;
 538   // FIXME: Get rid of the copies here by taking in a mutable clangd::Diag.
 539   for (auto &Entry : D.OpaqueData)
 540     Main.data.insert({Entry.first, Entry.second});
 541   OutFn(std::move(Main), D.Fixes);
 542
 543   // If we didn't emit the notes as relatedLocations, emit separate diagnostics
 544   // so the user can find the locations easily.
 545   if (!Opts.EmitRelatedLocations)
 546     for (auto &Note : D.Notes) {
 547       if (!Note.InsideMainFile)
 548         continue;
 549       clangd::Diagnostic Res;
 550       Res.severity = getSeverity(Note.Severity);
 551       Res.range = Note.Range;
 552       Res.message = noteMessage(D, Note, Opts);
 553       OutFn(std::move(Res), llvm::ArrayRef<Fix>());
 554     }
 555 }
 556
 557 int getSeverity(DiagnosticsEngine::Level L) {
 558   switch (L) {
 559   case DiagnosticsEngine::Remark:
 560     return 4;
 561   case DiagnosticsEngine::Note:
 562     return 3;
 563   case DiagnosticsEngine::Warning:
 564     return 2;
 565   case DiagnosticsEngine::Fatal:
 566   case DiagnosticsEngine::Error:
 567     return 1;
 568   case DiagnosticsEngine::Ignored:
 569     return 0;
 570   }
 571   llvm_unreachable("Unknown diagnostic level!");
 572 }
 573
 574 std::vector<Diag> StoreDiags::take(const clang::tidy::ClangTidyContext *Tidy) {
 575   // Do not forget to emit a pending diagnostic if there is one.
 576   flushLastDiag();
 577
 578   // Fill in name/source now that we have all the context needed to map them.
 579   for (auto &Diag : Output) {
 580     if (const char *ClangDiag = getDiagnosticCode(Diag.ID)) {
 581       // Warnings controlled by -Wfoo are better recognized by that name.
 582       StringRef Warning = DiagnosticIDs::getWarningOptionForDiag(Diag.ID);
 583       if (!Warning.empty()) {
 584         Diag.Name = ("-W" + Warning).str();
 585       } else {
 586         StringRef Name(ClangDiag);
 587         // Almost always an error, with a name like err_enum_class_reference.
 588         // Drop the err_ prefix for brevity.
 589         Name.consume_front("err_");
 590         Diag.Name = std::string(Name);
 591       }
 592       Diag.Source = Diag::Clang;
 593     } else if (Tidy != nullptr) {
 594       std::string TidyDiag = Tidy->getCheckName(Diag.ID);
 595       if (!TidyDiag.empty()) {
 596         Diag.Name = std::move(TidyDiag);
 597         Diag.Source = Diag::ClangTidy;
 598         // clang-tidy bakes the name into diagnostic messages. Strip it out.
 599         // It would be much nicer to make clang-tidy not do this.
 600         auto CleanMessage = [&](std::string &Msg) {
 601           StringRef Rest(Msg);
 602           if (Rest.consume_back("]") && Rest.consume_back(Diag.Name) &&
 603               Rest.consume_back(" ["))
 604             Msg.resize(Rest.size());
 605         };
 606         CleanMessage(Diag.Message);
 607         for (auto &Note : Diag.Notes)
 608           CleanMessage(Note.Message);
 609         for (auto &Fix : Diag.Fixes)
 610           CleanMessage(Fix.Message);
 611       }
 612     }
 613     setTags(Diag);
 614   }
 615   // Deduplicate clang-tidy diagnostics -- some clang-tidy checks may emit
 616   // duplicated messages due to various reasons (e.g. the check doesn't handle
 617   // template instantiations well; clang-tidy alias checks).
 618   std::set<std::pair<Range, std::string>> SeenDiags;
 619   llvm::erase_if(Output, [&](const Diag &D) {
 620     return !SeenDiags.emplace(D.Range, D.Message).second;
 621   });
 622   return std::move(Output);
 623 }
 624
 625 void StoreDiags::BeginSourceFile(const LangOptions &Opts,
 626                                  const Preprocessor *PP) {
 627   LangOpts = Opts;
 628   if (PP) {
 629     OrigSrcMgr = &PP->getSourceManager();
 630   }
 631 }
 632
 633 void StoreDiags::EndSourceFile() {
 634   flushLastDiag();
 635   LangOpts = std::nullopt;
 636   OrigSrcMgr = nullptr;
 637 }
 638
 639 /// Sanitizes a piece for presenting it in a synthesized fix message. Ensures
 640 /// the result is not too large and does not contain newlines.
 641 static void writeCodeToFixMessage(llvm::raw_ostream &OS, llvm::StringRef Code) {
 642   constexpr unsigned MaxLen = 50;
 643   if (Code == "\n") {
 644     OS << "\\n";
 645     return;
 646   }
 647   // Only show the first line if there are many.
 648   llvm::StringRef R = Code.split('\n').first;
 649   // Shorten the message if it's too long.
 650   R = R.take_front(MaxLen);
 651
 652   OS << R;
 653   if (R.size() != Code.size())
 654     OS << "…";
 655 }
 656
 657 /// Fills \p D with all information, except the location-related bits.
 658 /// Also note that ID and Name are not part of clangd::DiagBase and should be
 659 /// set elsewhere.
 660 static void fillNonLocationData(DiagnosticsEngine::Level DiagLevel,
 661                                 const clang::Diagnostic &Info,
 662                                 clangd::DiagBase &D) {
 663   llvm::SmallString<64> Message;
 664   Info.FormatDiagnostic(Message);
 665
 666   D.Message = std::string(Message.str());
 667   D.Severity = DiagLevel;
 668   D.Category = DiagnosticIDs::getCategoryNameFromID(
 669                    DiagnosticIDs::getCategoryNumberForDiag(Info.getID()))
 670                    .str();
 671 }
 672
 673 void StoreDiags::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
 674                                   const clang::Diagnostic &Info) {
 675   // If the diagnostic was generated for a different SourceManager, skip it.
 676   // This happens when a module is imported and needs to be implicitly built.
 677   // The compilation of that module will use the same StoreDiags, but different
 678   // SourceManager.
 679   if (OrigSrcMgr && Info.hasSourceManager() &&
 680       OrigSrcMgr != &Info.getSourceManager()) {
 681     IgnoreDiagnostics::log(DiagLevel, Info);
 682     return;
 683   }
 684
 685   DiagnosticConsumer::HandleDiagnostic(DiagLevel, Info);
 686   bool OriginallyError =
 687       Info.getDiags()->getDiagnosticIDs()->isDefaultMappingAsError(
 688           Info.getID());
 689
 690   if (Info.getLocation().isInvalid()) {
 691     // Handle diagnostics coming from command-line arguments. The source manager
 692     // is *not* available at this point, so we cannot use it.
 693     if (!OriginallyError) {
 694       IgnoreDiagnostics::log(DiagLevel, Info);
 695       return; // non-errors add too much noise, do not show them.
 696     }
 697
 698     flushLastDiag();
 699
 700     LastDiag = Diag();
 701     LastDiagLoc.reset();
 702     LastDiagOriginallyError = OriginallyError;
 703     LastDiag->ID = Info.getID();
 704     fillNonLocationData(DiagLevel, Info, *LastDiag);
 705     LastDiag->InsideMainFile = true;
 706     // Put it at the start of the main file, for a lack of a better place.
 707     LastDiag->Range.start = Position{0, 0};
 708     LastDiag->Range.end = Position{0, 0};
 709     return;
 710   }
 711
 712   if (!LangOpts || !Info.hasSourceManager()) {
 713     IgnoreDiagnostics::log(DiagLevel, Info);
 714     return;
 715   }
 716
 717   SourceManager &SM = Info.getSourceManager();
 718
 719   auto FillDiagBase = [&](DiagBase &D) {
 720     fillNonLocationData(DiagLevel, Info, D);
 721
 722     SourceLocation PatchLoc =
 723         translatePreamblePatchLocation(Info.getLocation(), SM);
 724     D.InsideMainFile = isInsideMainFile(PatchLoc, SM);
 725     if (auto DRange = diagnosticRange(Info, *LangOpts))
 726       D.Range = *DRange;
 727     else
 728       D.Severity = DiagnosticsEngine::Ignored;
 729     auto FID = SM.getFileID(Info.getLocation());
 730     if (const auto FE = SM.getFileEntryRefForID(FID)) {
 731       D.File = FE->getName().str();
 732       D.AbsFile = getCanonicalPath(*FE, SM.getFileManager());
 733     }
 734     D.ID = Info.getID();
 735     return D;
 736   };
 737
 738   auto AddFix = [&](bool SyntheticMessage) -> bool {
 739     assert(!Info.getFixItHints().empty() &&
 740            "diagnostic does not have attached fix-its");
 741     // No point in generating fixes, if the diagnostic is for a different file.
 742     if (!LastDiag->InsideMainFile)
 743       return false;
 744     // Copy as we may modify the ranges.
 745     auto FixIts = Info.getFixItHints().vec();
 746     llvm::SmallVector<TextEdit, 1> Edits;
 747     for (auto &FixIt : FixIts) {
 748       // Allow fixits within a single macro-arg expansion to be applied.
 749       // This can be incorrect if the argument is expanded multiple times in
 750       // different contexts. Hopefully this is rare!
 751       if (FixIt.RemoveRange.getBegin().isMacroID() &&
 752           FixIt.RemoveRange.getEnd().isMacroID() &&
 753           SM.getFileID(FixIt.RemoveRange.getBegin()) ==
 754               SM.getFileID(FixIt.RemoveRange.getEnd())) {
 755         FixIt.RemoveRange = CharSourceRange(
 756             {SM.getTopMacroCallerLoc(FixIt.RemoveRange.getBegin()),
 757              SM.getTopMacroCallerLoc(FixIt.RemoveRange.getEnd())},
 758             FixIt.RemoveRange.isTokenRange());
 759       }
 760       // Otherwise, follow clang's behavior: no fixits in macros.
 761       if (FixIt.RemoveRange.getBegin().isMacroID() ||
 762           FixIt.RemoveRange.getEnd().isMacroID())
 763         return false;
 764       if (!isInsideMainFile(FixIt.RemoveRange.getBegin(), SM))
 765         return false;
 766       Edits.push_back(toTextEdit(FixIt, SM, *LangOpts));
 767     }
 768
 769     llvm::SmallString<64> Message;
 770     // If requested and possible, create a message like "change 'foo' to 'bar'".
 771     if (SyntheticMessage && FixIts.size() == 1) {
 772       const auto &FixIt = FixIts.front();
 773       bool Invalid = false;
 774       llvm::StringRef Remove =
 775           Lexer::getSourceText(FixIt.RemoveRange, SM, *LangOpts, &Invalid);
 776       llvm::StringRef Insert = FixIt.CodeToInsert;
 777       if (!Invalid) {
 778         llvm::raw_svector_ostream M(Message);
 779         if (!Remove.empty() && !Insert.empty()) {
 780           M << "change '";
 781           writeCodeToFixMessage(M, Remove);
 782           M << "' to '";
 783           writeCodeToFixMessage(M, Insert);
 784           M << "'";
 785         } else if (!Remove.empty()) {
 786           M << "remove '";
 787           writeCodeToFixMessage(M, Remove);
 788           M << "'";
 789         } else if (!Insert.empty()) {
 790           M << "insert '";
 791           writeCodeToFixMessage(M, Insert);
 792           M << "'";
 793         }
 794         // Don't allow source code to inject newlines into diagnostics.
 795         std::replace(Message.begin(), Message.end(), '\n', ' ');
 796       }
 797     }
 798     if (Message.empty()) // either !SyntheticMessage, or we failed to make one.
 799       Info.FormatDiagnostic(Message);
 800     LastDiag->Fixes.push_back(
 801         Fix{std::string(Message.str()), std::move(Edits), {}});
 802     return true;
 803   };
 804
 805   if (!isNote(DiagLevel)) {
 806     // Handle the new main diagnostic.
 807     flushLastDiag();
 808
 809     LastDiag = Diag();
 810     // FIXME: Merge with feature modules.
 811     if (Adjuster)
 812       DiagLevel = Adjuster(DiagLevel, Info);
 813
 814     FillDiagBase(*LastDiag);
 815     if (isExcluded(LastDiag->ID))
 816       LastDiag->Severity = DiagnosticsEngine::Ignored;
 817     if (DiagCB)
 818       DiagCB(Info, *LastDiag);
 819     // Don't bother filling in the rest if diag is going to be dropped.
 820     if (LastDiag->Severity == DiagnosticsEngine::Ignored)
 821       return;
 822
 823     LastDiagLoc.emplace(Info.getLocation(), Info.getSourceManager());
 824     LastDiagOriginallyError = OriginallyError;
 825     if (!Info.getFixItHints().empty())
 826       AddFix(true /* try to invent a message instead of repeating the diag */);
 827     if (Fixer) {
 828       auto ExtraFixes = Fixer(LastDiag->Severity, Info);
 829       LastDiag->Fixes.insert(LastDiag->Fixes.end(), ExtraFixes.begin(),
 830                              ExtraFixes.end());
 831     }
 832   } else {
 833     // Handle a note to an existing diagnostic.
 834     if (!LastDiag) {
 835       assert(false && "Adding a note without main diagnostic");
 836       IgnoreDiagnostics::log(DiagLevel, Info);
 837       return;
 838     }
 839
 840     // If a diagnostic was suppressed due to the suppression filter,
 841     // also suppress notes associated with it.
 842     if (LastDiag->Severity == DiagnosticsEngine::Ignored)
 843       return;
 844
 845     // Give include-fixer a chance to replace a note with a fix.
 846     if (Fixer) {
 847       auto ReplacementFixes = Fixer(LastDiag->Severity, Info);
 848       if (!ReplacementFixes.empty()) {
 849         assert(Info.getNumFixItHints() == 0 &&
 850                "Include-fixer replaced a note with clang fix-its attached!");
 851         LastDiag->Fixes.insert(LastDiag->Fixes.end(), ReplacementFixes.begin(),
 852                                ReplacementFixes.end());
 853         return;
 854       }
 855     }
 856
 857     if (!Info.getFixItHints().empty()) {
 858       // A clang note with fix-it is not a separate diagnostic in clangd. We
 859       // attach it as a Fix to the main diagnostic instead.
 860       if (!AddFix(false /* use the note as the message */))
 861         IgnoreDiagnostics::log(DiagLevel, Info);
 862     } else {
 863       // A clang note without fix-its corresponds to clangd::Note.
 864       Note N;
 865       FillDiagBase(N);
 866
 867       LastDiag->Notes.push_back(std::move(N));
 868     }
 869   }
 870 }
 871
 872 void StoreDiags::flushLastDiag() {
 873   if (!LastDiag)
 874     return;
 875   auto Finish = llvm::make_scope_exit([&, NDiags(Output.size())] {
 876     if (Output.size() == NDiags) // No new diag emitted.
 877       vlog("Dropped diagnostic: {0}: {1}", LastDiag->File, LastDiag->Message);
 878     LastDiag.reset();
 879   });
 880
 881   if (LastDiag->Severity == DiagnosticsEngine::Ignored)
 882     return;
 883   // Move errors that occur from headers into main file.
 884   if (!LastDiag->InsideMainFile && LastDiagLoc && LastDiagOriginallyError) {
 885     if (tryMoveToMainFile(*LastDiag, *LastDiagLoc)) {
 886       // Suppress multiple errors from the same inclusion.
 887       if (!IncludedErrorLocations
 888                .insert({LastDiag->Range.start.line,
 889                         LastDiag->Range.start.character})
 890                .second)
 891         return;
 892     }
 893   }
 894   if (!mentionsMainFile(*LastDiag))
 895     return;
 896   Output.push_back(std::move(*LastDiag));
 897 }
 898
 899 bool isBuiltinDiagnosticSuppressed(unsigned ID,
 900                                    const llvm::StringSet<> &Suppress,
 901                                    const LangOptions &LangOpts) {
 902   // Don't complain about header-only stuff in mainfiles if it's a header.
 903   // FIXME: would be cleaner to suppress in clang, once we decide whether the
 904   //        behavior should be to silently-ignore or respect the pragma.
 905   if (ID == diag::pp_pragma_sysheader_in_main_file && LangOpts.IsHeaderFile)
 906     return true;
 907
 908   if (const char *CodePtr = getDiagnosticCode(ID)) {
 909     if (Suppress.contains(normalizeSuppressedCode(CodePtr)))
 910       return true;
 911   }
 912   StringRef Warning = DiagnosticIDs::getWarningOptionForDiag(ID);
 913   if (!Warning.empty() && Suppress.contains(Warning))
 914     return true;
 915   return false;
 916 }
 917
 918 llvm::StringRef normalizeSuppressedCode(llvm::StringRef Code) {
 919   Code.consume_front("err_");
 920   Code.consume_front("-W");
 921   return Code;
 922 }
 923
 924 std::optional<std::string> getDiagnosticDocURI(Diag::DiagSource Source,
 925                                                unsigned ID,
 926                                                llvm::StringRef Name) {
 927   switch (Source) {
 928   case Diag::Unknown:
 929     break;
 930   case Diag::Clang:
 931     // There is a page listing many warning flags, but it provides too little
 932     // information to be worth linking.
 933     // https://clang.llvm.org/docs/DiagnosticsReference.html
 934     break;
 935   case Diag::ClangTidy: {
 936     StringRef Module, Check;
 937     // This won't correctly get the module for clang-analyzer checks, but as we
 938     // don't link in the analyzer that shouldn't be an issue.
 939     // This would also need updating if anyone decides to create a module with a
 940     // '-' in the name.
 941     std::tie(Module, Check) = Name.split('-');
 942     if (Module.empty() || Check.empty())
 943       return std::nullopt;
 944     return ("https://clang.llvm.org/extra/clang-tidy/checks/" + Module + "/" +
 945             Check + ".html")
 946         .str();
 947   }
 948   case Diag::Clangd:
 949     if (Name == "unused-includes" || Name == "missing-includes")
 950       return {"https://clangd.llvm.org/guides/include-cleaner"};
 951     break;
 952   case Diag::ClangdConfig:
 953     // FIXME: we should link to https://clangd.llvm.org/config
 954     // However we have no diagnostic codes, which the link should describe!
 955     break;
 956   }
 957   return std::nullopt;
 958 }
 959
 960 } // namespace clangd
 961 } // namespace clang