llvm/lib/Option/OptTable.cpp

   1 //===- OptTable.cpp - Option Table Implementation -------------------------===//
   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 "llvm/Option/OptTable.h"
  10 #include "llvm/ADT/STLExtras.h"
  11 #include "llvm/ADT/StringRef.h"
  12 #include "llvm/ADT/StringSet.h"
  13 #include "llvm/Option/Arg.h"
  14 #include "llvm/Option/ArgList.h"
  15 #include "llvm/Option/OptSpecifier.h"
  16 #include "llvm/Option/Option.h"
  17 #include "llvm/Support/CommandLine.h" // for expandResponseFiles
  18 #include "llvm/Support/Compiler.h"
  19 #include "llvm/Support/ErrorHandling.h"
  20 #include "llvm/Support/raw_ostream.h"
  21 #include <algorithm>
  22 #include <cassert>
  23 #include <cctype>
  24 #include <cstring>
  25 #include <map>
  26 #include <string>
  27 #include <utility>
  28 #include <vector>
  29
  30 using namespace llvm;
  31 using namespace llvm::opt;
  32
  33 namespace llvm {
  34 namespace opt {
  35
  36 // Ordering on Info. The ordering is *almost* case-insensitive lexicographic,
  37 // with an exception. '\0' comes at the end of the alphabet instead of the
  38 // beginning (thus options precede any other options which prefix them).
  39 static int StrCmpOptionNameIgnoreCase(const char *A, const char *B) {
  40   const char *X = A, *Y = B;
  41   char a = tolower(*A), b = tolower(*B);
  42   while (a == b) {
  43     if (a == '\0')
  44       return 0;
  45
  46     a = tolower(*++X);
  47     b = tolower(*++Y);
  48   }
  49
  50   if (a == '\0') // A is a prefix of B.
  51     return 1;
  52   if (b == '\0') // B is a prefix of A.
  53     return -1;
  54
  55   // Otherwise lexicographic.
  56   return (a < b) ? -1 : 1;
  57 }
  58
  59 #ifndef NDEBUG
  60 static int StrCmpOptionName(const char *A, const char *B) {
  61   if (int N = StrCmpOptionNameIgnoreCase(A, B))
  62     return N;
  63   return strcmp(A, B);
  64 }
  65
  66 static inline bool operator<(const OptTable::Info &A, const OptTable::Info &B) {
  67   if (&A == &B)
  68     return false;
  69
  70   if (int N = StrCmpOptionName(A.Name, B.Name))
  71     return N < 0;
  72
  73   for (const char * const *APre = A.Prefixes,
  74                   * const *BPre = B.Prefixes;
  75                           *APre != nullptr && *BPre != nullptr; ++APre, ++BPre){
  76     if (int N = StrCmpOptionName(*APre, *BPre))
  77       return N < 0;
  78   }
  79
  80   // Names are the same, check that classes are in order; exactly one
  81   // should be joined, and it should succeed the other.
  82   assert(((A.Kind == Option::JoinedClass) ^ (B.Kind == Option::JoinedClass)) &&
  83          "Unexpected classes for options with same name.");
  84   return B.Kind == Option::JoinedClass;
  85 }
  86 #endif
  87
  88 // Support lower_bound between info and an option name.
  89 static inline bool operator<(const OptTable::Info &I, const char *Name) {
  90   return StrCmpOptionNameIgnoreCase(I.Name, Name) < 0;
  91 }
  92
  93 } // end namespace opt
  94 } // end namespace llvm
  95
  96 OptSpecifier::OptSpecifier(const Option *Opt) : ID(Opt->getID()) {}
  97
  98 OptTable::OptTable(ArrayRef<Info> OptionInfos, bool IgnoreCase)
  99     : OptionInfos(OptionInfos), IgnoreCase(IgnoreCase) {
 100   // Explicitly zero initialize the error to work around a bug in array
 101   // value-initialization on MinGW with gcc 4.3.5.
 102
 103   // Find start of normal options.
 104   for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
 105     unsigned Kind = getInfo(i + 1).Kind;
 106     if (Kind == Option::InputClass) {
 107       assert(!TheInputOptionID && "Cannot have multiple input options!");
 108       TheInputOptionID = getInfo(i + 1).ID;
 109     } else if (Kind == Option::UnknownClass) {
 110       assert(!TheUnknownOptionID && "Cannot have multiple unknown options!");
 111       TheUnknownOptionID = getInfo(i + 1).ID;
 112     } else if (Kind != Option::GroupClass) {
 113       FirstSearchableIndex = i;
 114       break;
 115     }
 116   }
 117   assert(FirstSearchableIndex != 0 && "No searchable options?");
 118
 119 #ifndef NDEBUG
 120   // Check that everything after the first searchable option is a
 121   // regular option class.
 122   for (unsigned i = FirstSearchableIndex, e = getNumOptions(); i != e; ++i) {
 123     Option::OptionClass Kind = (Option::OptionClass) getInfo(i + 1).Kind;
 124     assert((Kind != Option::InputClass && Kind != Option::UnknownClass &&
 125             Kind != Option::GroupClass) &&
 126            "Special options should be defined first!");
 127   }
 128
 129   // Check that options are in order.
 130   for (unsigned i = FirstSearchableIndex + 1, e = getNumOptions(); i != e; ++i){
 131     if (!(getInfo(i) < getInfo(i + 1))) {
 132       getOption(i).dump();
 133       getOption(i + 1).dump();
 134       llvm_unreachable("Options are not in order!");
 135     }
 136   }
 137 #endif
 138
 139   // Build prefixes.
 140   for (unsigned i = FirstSearchableIndex + 1, e = getNumOptions() + 1;
 141                 i != e; ++i) {
 142     if (const char *const *P = getInfo(i).Prefixes) {
 143       for (; *P != nullptr; ++P) {
 144         PrefixesUnion.insert(*P);
 145       }
 146     }
 147   }
 148
 149   // Build prefix chars.
 150   for (StringSet<>::const_iterator I = PrefixesUnion.begin(),
 151                                    E = PrefixesUnion.end(); I != E; ++I) {
 152     StringRef Prefix = I->getKey();
 153     for (StringRef::const_iterator C = Prefix.begin(), CE = Prefix.end();
 154                                    C != CE; ++C)
 155       if (!is_contained(PrefixChars, *C))
 156         PrefixChars.push_back(*C);
 157   }
 158 }
 159
 160 OptTable::~OptTable() = default;
 161
 162 const Option OptTable::getOption(OptSpecifier Opt) const {
 163   unsigned id = Opt.getID();
 164   if (id == 0)
 165     return Option(nullptr, nullptr);
 166   assert((unsigned) (id - 1) < getNumOptions() && "Invalid ID.");
 167   return Option(&getInfo(id), this);
 168 }
 169
 170 static bool isInput(const StringSet<> &Prefixes, StringRef Arg) {
 171   if (Arg == "-")
 172     return true;
 173   for (StringSet<>::const_iterator I = Prefixes.begin(),
 174                                    E = Prefixes.end(); I != E; ++I)
 175     if (Arg.startswith(I->getKey()))
 176       return false;
 177   return true;
 178 }
 179
 180 /// \returns Matched size. 0 means no match.
 181 static unsigned matchOption(const OptTable::Info *I, StringRef Str,
 182                             bool IgnoreCase) {
 183   for (const char * const *Pre = I->Prefixes; *Pre != nullptr; ++Pre) {
 184     StringRef Prefix(*Pre);
 185     if (Str.startswith(Prefix)) {
 186       StringRef Rest = Str.substr(Prefix.size());
 187       bool Matched = IgnoreCase ? Rest.startswith_insensitive(I->Name)
 188                                 : Rest.startswith(I->Name);
 189       if (Matched)
 190         return Prefix.size() + StringRef(I->Name).size();
 191     }
 192   }
 193   return 0;
 194 }
 195
 196 // Returns true if one of the Prefixes + In.Names matches Option
 197 static bool optionMatches(const OptTable::Info &In, StringRef Option) {
 198   if (In.Prefixes) {
 199     StringRef InName(In.Name);
 200     for (size_t I = 0; In.Prefixes[I]; I++)
 201       if (Option.endswith(InName))
 202         if (Option.slice(0, Option.size() - InName.size()) == In.Prefixes[I])
 203           return true;
 204   }
 205   return false;
 206 }
 207
 208 // This function is for flag value completion.
 209 // Eg. When "-stdlib=" and "l" was passed to this function, it will return
 210 // appropiriate values for stdlib, which starts with l.
 211 std::vector<std::string>
 212 OptTable::suggestValueCompletions(StringRef Option, StringRef Arg) const {
 213   // Search all options and return possible values.
 214   for (size_t I = FirstSearchableIndex, E = OptionInfos.size(); I < E; I++) {
 215     const Info &In = OptionInfos[I];
 216     if (!In.Values || !optionMatches(In, Option))
 217       continue;
 218
 219     SmallVector<StringRef, 8> Candidates;
 220     StringRef(In.Values).split(Candidates, ",", -1, false);
 221
 222     std::vector<std::string> Result;
 223     for (StringRef Val : Candidates)
 224       if (Val.startswith(Arg) && Arg.compare(Val))
 225         Result.push_back(std::string(Val));
 226     return Result;
 227   }
 228   return {};
 229 }
 230
 231 std::vector<std::string>
 232 OptTable::findByPrefix(StringRef Cur, unsigned int DisableFlags) const {
 233   std::vector<std::string> Ret;
 234   for (size_t I = FirstSearchableIndex, E = OptionInfos.size(); I < E; I++) {
 235     const Info &In = OptionInfos[I];
 236     if (!In.Prefixes || (!In.HelpText && !In.GroupID))
 237       continue;
 238     if (In.Flags & DisableFlags)
 239       continue;
 240
 241     for (int I = 0; In.Prefixes[I]; I++) {
 242       std::string S = std::string(In.Prefixes[I]) + std::string(In.Name) + "\t";
 243       if (In.HelpText)
 244         S += In.HelpText;
 245       if (StringRef(S).startswith(Cur) && S != std::string(Cur) + "\t")
 246         Ret.push_back(S);
 247     }
 248   }
 249   return Ret;
 250 }
 251
 252 unsigned OptTable::findNearest(StringRef Option, std::string &NearestString,
 253                                unsigned FlagsToInclude, unsigned FlagsToExclude,
 254                                unsigned MinimumLength) const {
 255   assert(!Option.empty());
 256
 257   // Consider each [option prefix + option name] pair as a candidate, finding
 258   // the closest match.
 259   unsigned BestDistance = UINT_MAX;
 260   for (const Info &CandidateInfo :
 261        ArrayRef<Info>(OptionInfos).drop_front(FirstSearchableIndex)) {
 262     StringRef CandidateName = CandidateInfo.Name;
 263
 264     // We can eliminate some option prefix/name pairs as candidates right away:
 265     // * Ignore option candidates with empty names, such as "--", or names
 266     //   that do not meet the minimum length.
 267     if (CandidateName.empty() || CandidateName.size() < MinimumLength)
 268       continue;
 269
 270     // * If FlagsToInclude were specified, ignore options that don't include
 271     //   those flags.
 272     if (FlagsToInclude && !(CandidateInfo.Flags & FlagsToInclude))
 273       continue;
 274     // * Ignore options that contain the FlagsToExclude.
 275     if (CandidateInfo.Flags & FlagsToExclude)
 276       continue;
 277
 278     // * Ignore positional argument option candidates (which do not
 279     //   have prefixes).
 280     if (!CandidateInfo.Prefixes)
 281       continue;
 282
 283     // Now check if the candidate ends with a character commonly used when
 284     // delimiting an option from its value, such as '=' or ':'. If it does,
 285     // attempt to split the given option based on that delimiter.
 286     StringRef LHS, RHS;
 287     char Last = CandidateName.back();
 288     bool CandidateHasDelimiter = Last == '=' || Last == ':';
 289     std::string NormalizedName = std::string(Option);
 290     if (CandidateHasDelimiter) {
 291       std::tie(LHS, RHS) = Option.split(Last);
 292       NormalizedName = std::string(LHS);
 293       if (Option.find(Last) == LHS.size())
 294         NormalizedName += Last;
 295     }
 296
 297     // Consider each possible prefix for each candidate to find the most
 298     // appropriate one. For example, if a user asks for "--helm", suggest
 299     // "--help" over "-help".
 300     for (int P = 0;
 301          const char *const CandidatePrefix = CandidateInfo.Prefixes[P]; P++) {
 302       std::string Candidate = (CandidatePrefix + CandidateName).str();
 303       StringRef CandidateRef = Candidate;
 304       unsigned Distance =
 305           CandidateRef.edit_distance(NormalizedName, /*AllowReplacements=*/true,
 306                                      /*MaxEditDistance=*/BestDistance);
 307       if (RHS.empty() && CandidateHasDelimiter) {
 308         // The Candidate ends with a = or : delimiter, but the option passed in
 309         // didn't contain the delimiter (or doesn't have anything after it).
 310         // In that case, penalize the correction: `-nodefaultlibs` is more
 311         // likely to be a spello for `-nodefaultlib` than `-nodefaultlib:` even
 312         // though both have an unmodified editing distance of 1, since the
 313         // latter would need an argument.
 314         ++Distance;
 315       }
 316       if (Distance < BestDistance) {
 317         BestDistance = Distance;
 318         NearestString = (Candidate + RHS).str();
 319       }
 320     }
 321   }
 322   return BestDistance;
 323 }
 324
 325 bool OptTable::addValues(const char *Option, const char *Values) {
 326   for (size_t I = FirstSearchableIndex, E = OptionInfos.size(); I < E; I++) {
 327     Info &In = OptionInfos[I];
 328     if (optionMatches(In, Option)) {
 329       In.Values = Values;
 330       return true;
 331     }
 332   }
 333   return false;
 334 }
 335
 336 // Parse a single argument, return the new argument, and update Index. If
 337 // GroupedShortOptions is true, -a matches "-abc" and the argument in Args will
 338 // be updated to "-bc". This overload does not support
 339 // FlagsToInclude/FlagsToExclude or case insensitive options.
 340 Arg *OptTable::parseOneArgGrouped(InputArgList &Args, unsigned &Index) const {
 341   // Anything that doesn't start with PrefixesUnion is an input, as is '-'
 342   // itself.
 343   const char *CStr = Args.getArgString(Index);
 344   StringRef Str(CStr);
 345   if (isInput(PrefixesUnion, Str))
 346     return new Arg(getOption(TheInputOptionID), Str, Index++, CStr);
 347
 348   const Info *End = OptionInfos.data() + OptionInfos.size();
 349   StringRef Name = Str.ltrim(PrefixChars);
 350   const Info *Start = std::lower_bound(
 351       OptionInfos.data() + FirstSearchableIndex, End, Name.data());
 352   const Info *Fallback = nullptr;
 353   unsigned Prev = Index;
 354
 355   // Search for the option which matches Str.
 356   for (; Start != End; ++Start) {
 357     unsigned ArgSize = matchOption(Start, Str, IgnoreCase);
 358     if (!ArgSize)
 359       continue;
 360
 361     Option Opt(Start, this);
 362     if (Arg *A = Opt.accept(Args, StringRef(Args.getArgString(Index), ArgSize),
 363                             false, Index))
 364       return A;
 365
 366     // If Opt is a Flag of length 2 (e.g. "-a"), we know it is a prefix of
 367     // the current argument (e.g. "-abc"). Match it as a fallback if no longer
 368     // option (e.g. "-ab") exists.
 369     if (ArgSize == 2 && Opt.getKind() == Option::FlagClass)
 370       Fallback = Start;
 371
 372     // Otherwise, see if the argument is missing.
 373     if (Prev != Index)
 374       return nullptr;
 375   }
 376   if (Fallback) {
 377     Option Opt(Fallback, this);
 378     if (Arg *A = Opt.accept(Args, Str.substr(0, 2), true, Index)) {
 379       if (Str.size() == 2)
 380         ++Index;
 381       else
 382         Args.replaceArgString(Index, Twine('-') + Str.substr(2));
 383       return A;
 384     }
 385   }
 386
 387   return new Arg(getOption(TheUnknownOptionID), Str, Index++, CStr);
 388 }
 389
 390 Arg *OptTable::ParseOneArg(const ArgList &Args, unsigned &Index,
 391                            unsigned FlagsToInclude,
 392                            unsigned FlagsToExclude) const {
 393   unsigned Prev = Index;
 394   const char *Str = Args.getArgString(Index);
 395
 396   // Anything that doesn't start with PrefixesUnion is an input, as is '-'
 397   // itself.
 398   if (isInput(PrefixesUnion, Str))
 399     return new Arg(getOption(TheInputOptionID), Str, Index++, Str);
 400
 401   const Info *Start = OptionInfos.data() + FirstSearchableIndex;
 402   const Info *End = OptionInfos.data() + OptionInfos.size();
 403   StringRef Name = StringRef(Str).ltrim(PrefixChars);
 404
 405   // Search for the first next option which could be a prefix.
 406   Start = std::lower_bound(Start, End, Name.data());
 407
 408   // Options are stored in sorted order, with '\0' at the end of the
 409   // alphabet. Since the only options which can accept a string must
 410   // prefix it, we iteratively search for the next option which could
 411   // be a prefix.
 412   //
 413   // FIXME: This is searching much more than necessary, but I am
 414   // blanking on the simplest way to make it fast. We can solve this
 415   // problem when we move to TableGen.
 416   for (; Start != End; ++Start) {
 417     unsigned ArgSize = 0;
 418     // Scan for first option which is a proper prefix.
 419     for (; Start != End; ++Start)
 420       if ((ArgSize = matchOption(Start, Str, IgnoreCase)))
 421         break;
 422     if (Start == End)
 423       break;
 424
 425     Option Opt(Start, this);
 426
 427     if (FlagsToInclude && !Opt.hasFlag(FlagsToInclude))
 428       continue;
 429     if (Opt.hasFlag(FlagsToExclude))
 430       continue;
 431
 432     // See if this option matches.
 433     if (Arg *A = Opt.accept(Args, StringRef(Args.getArgString(Index), ArgSize),
 434                             false, Index))
 435       return A;
 436
 437     // Otherwise, see if this argument was missing values.
 438     if (Prev != Index)
 439       return nullptr;
 440   }
 441
 442   // If we failed to find an option and this arg started with /, then it's
 443   // probably an input path.
 444   if (Str[0] == '/')
 445     return new Arg(getOption(TheInputOptionID), Str, Index++, Str);
 446
 447   return new Arg(getOption(TheUnknownOptionID), Str, Index++, Str);
 448 }
 449
 450 InputArgList OptTable::ParseArgs(ArrayRef<const char *> ArgArr,
 451                                  unsigned &MissingArgIndex,
 452                                  unsigned &MissingArgCount,
 453                                  unsigned FlagsToInclude,
 454                                  unsigned FlagsToExclude) const {
 455   InputArgList Args(ArgArr.begin(), ArgArr.end());
 456
 457   // FIXME: Handle '@' args (or at least error on them).
 458
 459   MissingArgIndex = MissingArgCount = 0;
 460   unsigned Index = 0, End = ArgArr.size();
 461   while (Index < End) {
 462     // Ingore nullptrs, they are response file's EOL markers
 463     if (Args.getArgString(Index) == nullptr) {
 464       ++Index;
 465       continue;
 466     }
 467     // Ignore empty arguments (other things may still take them as arguments).
 468     StringRef Str = Args.getArgString(Index);
 469     if (Str == "") {
 470       ++Index;
 471       continue;
 472     }
 473
 474     unsigned Prev = Index;
 475     Arg *A = GroupedShortOptions
 476                  ? parseOneArgGrouped(Args, Index)
 477                  : ParseOneArg(Args, Index, FlagsToInclude, FlagsToExclude);
 478     assert((Index > Prev || GroupedShortOptions) &&
 479            "Parser failed to consume argument.");
 480
 481     // Check for missing argument error.
 482     if (!A) {
 483       assert(Index >= End && "Unexpected parser error.");
 484       assert(Index - Prev - 1 && "No missing arguments!");
 485       MissingArgIndex = Prev;
 486       MissingArgCount = Index - Prev - 1;
 487       break;
 488     }
 489
 490     Args.append(A);
 491   }
 492
 493   return Args;
 494 }
 495
 496 InputArgList OptTable::parseArgs(int Argc, char *const *Argv,
 497                                  OptSpecifier Unknown, StringSaver &Saver,
 498                                  function_ref<void(StringRef)> ErrorFn) const {
 499   SmallVector<const char *, 0> NewArgv;
 500   // The environment variable specifies initial options which can be overridden
 501   // by commnad line options.
 502   cl::expandResponseFiles(Argc, Argv, EnvVar, Saver, NewArgv);
 503
 504   unsigned MAI, MAC;
 505   opt::InputArgList Args = ParseArgs(makeArrayRef(NewArgv), MAI, MAC);
 506   if (MAC)
 507     ErrorFn((Twine(Args.getArgString(MAI)) + ": missing argument").str());
 508
 509   // For each unknwon option, call ErrorFn with a formatted error message. The
 510   // message includes a suggested alternative option spelling if available.
 511   std::string Nearest;
 512   for (const opt::Arg *A : Args.filtered(Unknown)) {
 513     std::string Spelling = A->getAsString(Args);
 514     if (findNearest(Spelling, Nearest) > 1)
 515       ErrorFn("unknown argument '" + A->getAsString(Args) + "'");
 516     else
 517       ErrorFn("unknown argument '" + A->getAsString(Args) +
 518               "', did you mean '" + Nearest + "'?");
 519   }
 520   return Args;
 521 }
 522
 523 static std::string getOptionHelpName(const OptTable &Opts, OptSpecifier Id) {
 524   const Option O = Opts.getOption(Id);
 525   std::string Name = O.getPrefixedName();
 526
 527   // Add metavar, if used.
 528   switch (O.getKind()) {
 529   case Option::GroupClass: case Option::InputClass: case Option::UnknownClass:
 530     llvm_unreachable("Invalid option with help text.");
 531
 532   case Option::MultiArgClass:
 533     if (const char *MetaVarName = Opts.getOptionMetaVar(Id)) {
 534       // For MultiArgs, metavar is full list of all argument names.
 535       Name += ' ';
 536       Name += MetaVarName;
 537     }
 538     else {
 539       // For MultiArgs<N>, if metavar not supplied, print <value> N times.
 540       for (unsigned i=0, e=O.getNumArgs(); i< e; ++i) {
 541         Name += " <value>";
 542       }
 543     }
 544     break;
 545
 546   case Option::FlagClass:
 547     break;
 548
 549   case Option::ValuesClass:
 550     break;
 551
 552   case Option::SeparateClass: case Option::JoinedOrSeparateClass:
 553   case Option::RemainingArgsClass: case Option::RemainingArgsJoinedClass:
 554     Name += ' ';
 555     LLVM_FALLTHROUGH;
 556   case Option::JoinedClass: case Option::CommaJoinedClass:
 557   case Option::JoinedAndSeparateClass:
 558     if (const char *MetaVarName = Opts.getOptionMetaVar(Id))
 559       Name += MetaVarName;
 560     else
 561       Name += "<value>";
 562     break;
 563   }
 564
 565   return Name;
 566 }
 567
 568 namespace {
 569 struct OptionInfo {
 570   std::string Name;
 571   StringRef HelpText;
 572 };
 573 } // namespace
 574
 575 static void PrintHelpOptionList(raw_ostream &OS, StringRef Title,
 576                                 std::vector<OptionInfo> &OptionHelp) {
 577   OS << Title << ":\n";
 578
 579   // Find the maximum option length.
 580   unsigned OptionFieldWidth = 0;
 581   for (unsigned i = 0, e = OptionHelp.size(); i != e; ++i) {
 582     // Limit the amount of padding we are willing to give up for alignment.
 583     unsigned Length = OptionHelp[i].Name.size();
 584     if (Length <= 23)
 585       OptionFieldWidth = std::max(OptionFieldWidth, Length);
 586   }
 587
 588   const unsigned InitialPad = 2;
 589   for (unsigned i = 0, e = OptionHelp.size(); i != e; ++i) {
 590     const std::string &Option = OptionHelp[i].Name;
 591     int Pad = OptionFieldWidth - int(Option.size());
 592     OS.indent(InitialPad) << Option;
 593
 594     // Break on long option names.
 595     if (Pad < 0) {
 596       OS << "\n";
 597       Pad = OptionFieldWidth + InitialPad;
 598     }
 599     OS.indent(Pad + 1) << OptionHelp[i].HelpText << '\n';
 600   }
 601 }
 602
 603 static const char *getOptionHelpGroup(const OptTable &Opts, OptSpecifier Id) {
 604   unsigned GroupID = Opts.getOptionGroupID(Id);
 605
 606   // If not in a group, return the default help group.
 607   if (!GroupID)
 608     return "OPTIONS";
 609
 610   // Abuse the help text of the option groups to store the "help group"
 611   // name.
 612   //
 613   // FIXME: Split out option groups.
 614   if (const char *GroupHelp = Opts.getOptionHelpText(GroupID))
 615     return GroupHelp;
 616
 617   // Otherwise keep looking.
 618   return getOptionHelpGroup(Opts, GroupID);
 619 }
 620
 621 void OptTable::printHelp(raw_ostream &OS, const char *Usage, const char *Title,
 622                          bool ShowHidden, bool ShowAllAliases) const {
 623   printHelp(OS, Usage, Title, /*Include*/ 0, /*Exclude*/
 624             (ShowHidden ? 0 : HelpHidden), ShowAllAliases);
 625 }
 626
 627 void OptTable::printHelp(raw_ostream &OS, const char *Usage, const char *Title,
 628                          unsigned FlagsToInclude, unsigned FlagsToExclude,
 629                          bool ShowAllAliases) const {
 630   OS << "OVERVIEW: " << Title << "\n\n";
 631   OS << "USAGE: " << Usage << "\n\n";
 632
 633   // Render help text into a map of group-name to a list of (option, help)
 634   // pairs.
 635   std::map<std::string, std::vector<OptionInfo>> GroupedOptionHelp;
 636
 637   for (unsigned Id = 1, e = getNumOptions() + 1; Id != e; ++Id) {
 638     // FIXME: Split out option groups.
 639     if (getOptionKind(Id) == Option::GroupClass)
 640       continue;
 641
 642     unsigned Flags = getInfo(Id).Flags;
 643     if (FlagsToInclude && !(Flags & FlagsToInclude))
 644       continue;
 645     if (Flags & FlagsToExclude)
 646       continue;
 647
 648     // If an alias doesn't have a help text, show a help text for the aliased
 649     // option instead.
 650     const char *HelpText = getOptionHelpText(Id);
 651     if (!HelpText && ShowAllAliases) {
 652       const Option Alias = getOption(Id).getAlias();
 653       if (Alias.isValid())
 654         HelpText = getOptionHelpText(Alias.getID());
 655     }
 656
 657     if (HelpText && (strlen(HelpText) != 0)) {
 658       const char *HelpGroup = getOptionHelpGroup(*this, Id);
 659       const std::string &OptName = getOptionHelpName(*this, Id);
 660       GroupedOptionHelp[HelpGroup].push_back({OptName, HelpText});
 661     }
 662   }
 663
 664   for (auto& OptionGroup : GroupedOptionHelp) {
 665     if (OptionGroup.first != GroupedOptionHelp.begin()->first)
 666       OS << "\n";
 667     PrintHelpOptionList(OS, OptionGroup.first, OptionGroup.second);
 668   }
 669
 670   OS.flush();
 671 }