llvm-project/clang/lib/Driver/OptTable.cpp

//===--- OptTable.cpp - Option Table Implementation ---------------------*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "clang/Driver/OptTable.h"
#include "clang/Driver/Arg.h"
#include "clang/Driver/ArgList.h"
#include "clang/Driver/Option.h"
#include <algorithm>
#include <cassert>

using namespace clang::driver;
using namespace clang::driver::options;

// Ordering on Info. The ordering is *almost* lexicographic, with two
// exceptions. First, '\0' comes at the end of the alphabet instead of
// the beginning (thus options preceed any other options which prefix
// them). Second, for options with the same name, the less permissive
// version should come first; a Flag option should preceed a Joined
// option, for example.

static int StrCmpOptionName(const char *A, const char *B) {
  char a = *A, b = *B;
  while (a == b) {
    if (a == '\0')
      return 0;

    a = *++A;
    b = *++B;
  }

  if (a == '\0') // A is a prefix of B.
    return 1;
  if (b == '\0') // B is a prefix of A.
    return -1;

  // Otherwise lexicographic.
  return (a < b) ? -1 : 1;
}

namespace clang {
namespace driver {
static inline bool operator<(const OptTable::Info &A, const OptTable::Info &B) {
  if (&A == &B)
    return false;

  if (int N = StrCmpOptionName(A.Name, B.Name))
    return N == -1;

  // Names are the same, check that classes are in order; exactly one
  // should be joined, and it should succeed the other.
  assert(((A.Kind == Option::JoinedClass) ^ (B.Kind == Option::JoinedClass)) &&
         "Unexpected classes for options with same name.");
  return B.Kind == Option::JoinedClass;
}

// Support lower_bound between info and an option name.
static inline bool operator<(const OptTable::Info &I, const char *Name) {
  return StrCmpOptionName(I.Name, Name) == -1;
}
static inline bool operator<(const char *Name, const OptTable::Info &I) {
  return StrCmpOptionName(Name, I.Name) == -1;
}
}
}

//

OptTable::OptTable(const Info *_OptionInfos, unsigned _NumOptionInfos)
  : OptionInfos(_OptionInfos), NumOptionInfos(_NumOptionInfos),
    Options(new Option*[NumOptionInfos]),
    TheInputOption(0), TheUnknownOption(0), FirstSearchableIndex(0)
{
  // Explicitly zero initialize the error to work around a bug in array
  // value-initialization on MinGW with gcc 4.3.5.
  memset(Options, 0, sizeof(*Options) * NumOptionInfos);

  // Find start of normal options.
  for (unsigned i = 0, e = getNumOptions(); i != e; ++i) {
    unsigned Kind = getInfo(i + 1).Kind;
    if (Kind == Option::InputClass) {
      assert(!TheInputOption && "Cannot have multiple input options!");
      TheInputOption = getOption(i + 1);
    } else if (Kind == Option::UnknownClass) {
      assert(!TheUnknownOption && "Cannot have multiple input options!");
      TheUnknownOption = getOption(i + 1);
    } else if (Kind != Option::GroupClass) {
      FirstSearchableIndex = i;
      break;
    }
  }
  assert(FirstSearchableIndex != 0 && "No searchable options?");

#ifndef NDEBUG
  // Check that everything after the first searchable option is a
  // regular option class.
  for (unsigned i = FirstSearchableIndex, e = getNumOptions(); i != e; ++i) {
    Option::OptionClass Kind = (Option::OptionClass) getInfo(i + 1).Kind;
    assert((Kind != Option::InputClass && Kind != Option::UnknownClass &&
            Kind != Option::GroupClass) &&
           "Special options should be defined first!");
  }

  // Check that options are in order.
  for (unsigned i = FirstSearchableIndex+1, e = getNumOptions(); i != e; ++i) {
    if (!(getInfo(i) < getInfo(i + 1))) {
      getOption(i)->dump();
      getOption(i + 1)->dump();
      assert(0 && "Options are not in order!");
    }
  }
#endif
}

OptTable::~OptTable() {
  for (unsigned i = 0, e = getNumOptions(); i != e; ++i)
    delete Options[i];
  delete[] Options;
}

Option *OptTable::CreateOption(unsigned id) const {
  const Info &info = getInfo(id);
  const OptionGroup *Group =
    cast_or_null<OptionGroup>(getOption(info.GroupID));
  const Option *Alias = getOption(info.AliasID);

  Option *Opt = 0;
  switch (info.Kind) {
  case Option::InputClass:
    Opt = new InputOption(); break;
  case Option::UnknownClass:
    Opt = new UnknownOption(); break;
  case Option::GroupClass:
    Opt = new OptionGroup(id, info.Name, Group); break;
  case Option::FlagClass:
    Opt = new FlagOption(id, info.Name, Group, Alias); break;
  case Option::JoinedClass:
    Opt = new JoinedOption(id, info.Name, Group, Alias); break;
  case Option::SeparateClass:
    Opt = new SeparateOption(id, info.Name, Group, Alias); break;
  case Option::CommaJoinedClass:
    Opt = new CommaJoinedOption(id, info.Name, Group, Alias); break;
  case Option::MultiArgClass:
    Opt = new MultiArgOption(id, info.Name, Group, Alias, info.Param); break;
  case Option::JoinedOrSeparateClass:
    Opt = new JoinedOrSeparateOption(id, info.Name, Group, Alias); break;
  case Option::JoinedAndSeparateClass:
    Opt = new JoinedAndSeparateOption(id, info.Name, Group, Alias); break;
  }

  if (info.Flags & DriverOption)
    Opt->setDriverOption(true);
  if (info.Flags & LinkerInput)
    Opt->setLinkerInput(true);
  if (info.Flags & NoArgumentUnused)
    Opt->setNoArgumentUnused(true);
  if (info.Flags & RenderAsInput)
    Opt->setNoOptAsInput(true);
  if (info.Flags & RenderJoined) {
    assert(info.Kind == Option::SeparateClass && "Invalid option.");
    Opt->setForceJoinedRender(true);
  }
  if (info.Flags & RenderSeparate) {
    assert(info.Kind == Option::JoinedClass && "Invalid option.");
    Opt->setForceSeparateRender(true);
  }
  if (info.Flags & Unsupported)
    Opt->setUnsupported(true);

  return Opt;
}

Arg *OptTable::ParseOneArg(const InputArgList &Args, unsigned &Index) const {
  unsigned Prev = Index;
  const char *Str = Args.getArgString(Index);

  // Anything that doesn't start with '-' is an input, as is '-' itself.
  if (Str[0] != '-' || Str[1] == '\0')
    return new PositionalArg(TheInputOption, Index++);

  const Info *Start = OptionInfos + FirstSearchableIndex;
  const Info *End = OptionInfos + LastOption - 1;

  // Search for the first next option which could be a prefix.
  Start = std::lower_bound(Start, End, Str);

  // Options are stored in sorted order, with '\0' at the end of the
  // alphabet. Since the only options which can accept a string must
  // prefix it, we iteratively search for the next option which could
  // be a prefix.
  //
  // FIXME: This is searching much more than necessary, but I am
  // blanking on the simplest way to make it fast. We can solve this
  // problem when we move to TableGen.
  for (; Start != End; ++Start) {
    // Scan for first option which is a proper prefix.
    for (; Start != End; ++Start)
      if (memcmp(Str, Start->Name, strlen(Start->Name)) == 0)
        break;
    if (Start == End)
      break;

    // See if this option matches.
    options::ID id = (options::ID) (Start - OptionInfos + 1);
    if (Arg *A = getOption(id)->accept(Args, Index))
      return A;

    // Otherwise, see if this argument was missing values.
    if (Prev != Index)
      return 0;
  }

  return new PositionalArg(TheUnknownOption, Index++);
}