Option.cpp

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//===- Option.cpp - Abstract Driver Options -------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/Option/Arg.h"
#include "llvm/Option/ArgList.h"
#include "llvm/Option/Option.h"
#include "llvm/Option/OptTable.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstring>

using namespace llvm;
using namespace llvm::opt;

Option::Option(const OptTable::Info *info, const OptTable *owner)
  : Info(info), Owner(owner) {
  // Multi-level aliases are not supported. This just simplifies option
  // tracking, it is not an inherent limitation.
  assert((!Info || !getAlias().isValid() || !getAlias().getAlias().isValid()) &&
         "Multi-level aliases are not supported.");

  if (Info && getAliasArgs()) {
    assert(getAlias().isValid() && "Only alias options can have alias args.");
    assert(getKind() == FlagClass && "Only Flag aliases can have alias args.");
    assert(getAlias().getKind() != FlagClass &&
           "Cannot provide alias args to a flag option.");
  }
}

void Option::print(raw_ostream &O) const {
  O << "<";
  switch (getKind()) {
#define P(N) case N: O << #N; break
    P(GroupClass);
    P(InputClass);
    P(UnknownClass);
    P(FlagClass);
    P(JoinedClass);
    P(ValuesClass);
    P(SeparateClass);
    P(CommaJoinedClass);
    P(MultiArgClass);
    P(JoinedOrSeparateClass);
    P(JoinedAndSeparateClass);
    P(RemainingArgsClass);
    P(RemainingArgsJoinedClass);
#undef P
  }

  if (Info->Prefixes) {
    O << " Prefixes:[";
    for (const char *const *Pre = Info->Prefixes; *Pre != nullptr; ++Pre) {
      O << '"' << *Pre << (*(Pre + 1) == nullptr ? "\"" : "\", ");
    }
    O << ']';
  }

  O << " Name:\"" << getName() << '"';

  const Option Group = getGroup();
  if (Group.isValid()) {
    O << " Group:";
    Group.print(O);
  }

  const Option Alias = getAlias();
  if (Alias.isValid()) {
    O << " Alias:";
    Alias.print(O);
  }

  if (getKind() == MultiArgClass)
    O << " NumArgs:" << getNumArgs();

  O << ">\n";
}

#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void Option::dump() const { print(dbgs()); }
#endif

bool Option::matches(OptSpecifier Opt) const {
  // Aliases are never considered in matching, look through them.
  const Option Alias = getAlias();
  if (Alias.isValid())
    return Alias.matches(Opt);

  // Check exact match.
  if (getID() == Opt.getID())
    return true;

  const Option Group = getGroup();
  if (Group.isValid())
    return Group.matches(Opt);
  return false;
}

Arg *Option::acceptInternal(const ArgList &Args, unsigned &Index,
                            unsigned ArgSize) const {
  StringRef Spelling = StringRef(Args.getArgString(Index), ArgSize);
  switch (getKind()) {
  case FlagClass: {
    if (ArgSize != strlen(Args.getArgString(Index)))
      return nullptr;
    return new Arg(*this, Spelling, Index++);
  }
  case JoinedClass: {
    const char *Value = Args.getArgString(Index) + ArgSize;
    return new Arg(*this, Spelling, Index++, Value);
  }
  case CommaJoinedClass: {
    // Always matches.
    const char *Str = Args.getArgString(Index) + ArgSize;
    Arg *A = new Arg(*this, Spelling, Index++);

    // Parse out the comma separated values.
    const char *Prev = Str;
    for (;; ++Str) {
      char c = *Str;

      if (!c || c == ',') {
        if (Prev != Str) {
          char *Value = new char[Str - Prev + 1];
          memcpy(Value, Prev, Str - Prev);
          Value[Str - Prev] = '\0';
          A->getValues().push_back(Value);
        }

        if (!c)
          break;

        Prev = Str + 1;
      }
    }
    A->setOwnsValues(true);

    return A;
  }
  case SeparateClass:
    // Matches iff this is an exact match.
    // FIXME: Avoid strlen.
    if (ArgSize != strlen(Args.getArgString(Index)))
      return nullptr;

    Index += 2;
    if (Index > Args.getNumInputArgStrings() ||
        Args.getArgString(Index - 1) == nullptr)
      return nullptr;

    return new Arg(*this, Spelling, Index - 2, Args.getArgString(Index - 1));
  case MultiArgClass: {
    // Matches iff this is an exact match.
    // FIXME: Avoid strlen.
    if (ArgSize != strlen(Args.getArgString(Index)))
      return nullptr;

    Index += 1 + getNumArgs();
    if (Index > Args.getNumInputArgStrings())
      return nullptr;

    Arg *A = new Arg(*this, Spelling, Index - 1 - getNumArgs(),
                     Args.getArgString(Index - getNumArgs()));
    for (unsigned i = 1; i != getNumArgs(); ++i)
      A->getValues().push_back(Args.getArgString(Index - getNumArgs() + i));
    return A;
  }
  case JoinedOrSeparateClass: {
    // If this is not an exact match, it is a joined arg.
    // FIXME: Avoid strlen.
    if (ArgSize != strlen(Args.getArgString(Index))) {
      const char *Value = Args.getArgString(Index) + ArgSize;
      return new Arg(*this, Spelling, Index++, Value);
    }

    // Otherwise it must be separate.
    Index += 2;
    if (Index > Args.getNumInputArgStrings() ||
        Args.getArgString(Index - 1) == nullptr)
      return nullptr;

    return new Arg(*this, Spelling, Index - 2, Args.getArgString(Index - 1));
  }
  case JoinedAndSeparateClass:
    // Always matches.
    Index += 2;
    if (Index > Args.getNumInputArgStrings() ||
        Args.getArgString(Index - 1) == nullptr)
      return nullptr;

    return new Arg(*this, Spelling, Index - 2,
                   Args.getArgString(Index - 2) + ArgSize,
                   Args.getArgString(Index - 1));
  case RemainingArgsClass: {
    // Matches iff this is an exact match.
    // FIXME: Avoid strlen.
    if (ArgSize != strlen(Args.getArgString(Index)))
      return nullptr;
    Arg *A = new Arg(*this, Spelling, Index++);
    while (Index < Args.getNumInputArgStrings() &&
           Args.getArgString(Index) != nullptr)
      A->getValues().push_back(Args.getArgString(Index++));
    return A;
  }
  case RemainingArgsJoinedClass: {
    Arg *A = new Arg(*this, Spelling, Index);
    if (ArgSize != strlen(Args.getArgString(Index))) {
      // An inexact match means there is a joined arg.
      A->getValues().push_back(Args.getArgString(Index) + ArgSize);
    }
    Index++;
    while (Index < Args.getNumInputArgStrings() &&
           Args.getArgString(Index) != nullptr)
      A->getValues().push_back(Args.getArgString(Index++));
    return A;
  }

  default:
    llvm_unreachable("Invalid option kind!");
  }
}

Arg *Option::accept(const ArgList &Args,
                    unsigned &Index,
                    unsigned ArgSize) const {
  std::unique_ptr<Arg> A(acceptInternal(Args, Index, ArgSize));
  if (!A)
    return nullptr;

  const Option &UnaliasedOption = getUnaliasedOption();
  if (getID() == UnaliasedOption.getID())
    return A.release();

  // "A" is an alias for a different flag. For most clients it's more convenient
  // if this function returns unaliased Args, so create an unaliased arg for
  // returning.

  // This creates a completely new Arg object for the unaliased Arg because
  // the alias and the unaliased arg can have different Kinds and different
  // Values (due to AliasArgs<>).

  // Get the spelling from the unaliased option.
  StringRef UnaliasedSpelling = Args.MakeArgString(
      Twine(UnaliasedOption.getPrefix()) + Twine(UnaliasedOption.getName()));

  // It's a bit weird that aliased and unaliased arg share one index, but
  // the index is mostly use as a memory optimization in render().
  // Due to this, ArgList::getArgString(A->getIndex()) will return the spelling
  // of the aliased arg always, while A->getSpelling() returns either the
  // unaliased or the aliased arg, depending on which Arg object it's called on.
  Arg *UnaliasedA = new Arg(UnaliasedOption, UnaliasedSpelling, A->getIndex());
  Arg *RawA = A.get();
  UnaliasedA->setAlias(std::move(A));

  if (getKind() != FlagClass) {
    // Values are usually owned by the ArgList. The exception are
    // CommaJoined flags, where the Arg owns the values. For aliased flags,
    // make the unaliased Arg the owner of the values.
    // FIXME: There aren't many uses of CommaJoined -- try removing
    // CommaJoined in favor of just calling StringRef::split(',') instead.
    UnaliasedA->getValues() = RawA->getValues();
    UnaliasedA->setOwnsValues(RawA->getOwnsValues());
    RawA->setOwnsValues(false);
    return UnaliasedA;
  }

  // FlagClass aliases can have AliasArgs<>; add those to the unaliased arg.
  if (const char *Val = getAliasArgs()) {
    while (*Val != '\0') {
      UnaliasedA->getValues().push_back(Val);

      // Move past the '\0' to the next argument.
      Val += strlen(Val) + 1;
    }
  }
  if (UnaliasedOption.getKind() == JoinedClass && !getAliasArgs())
    // A Flag alias for a Joined option must provide an argument.
    UnaliasedA->getValues().push_back("");
  return UnaliasedA;
}