text: //===- Multilib.h -----------------------------------------------*- C++ -*-===//
  //
  // 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
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef LLVM_CLANG_DRIVER_MULTILIB_H
  #define LLVM_CLANG_DRIVER_MULTILIB_H
  
  #include "clang/Basic/LLVM.h"
  #include "llvm/ADT/ArrayRef.h"
  #include "llvm/ADT/STLExtras.h"
  #include "llvm/ADT/StringRef.h"
  #include "llvm/Support/Compiler.h"
  #include <cassert>
  #include <functional>
  #include <string>
  #include <utility>
  #include <vector>
  
  namespace clang {
  namespace driver {
  
  /// This corresponds to a single GCC Multilib, or a segment of one controlled
  /// by a command line flag
  class Multilib {
  public:
    using flags_list = std::vector<std::string>;
  
  private:
    std::string GCCSuffix;
    std::string OSSuffix;
    std::string IncludeSuffix;
    flags_list Flags;
  
  public:
    Multilib(StringRef GCCSuffix = {}, StringRef OSSuffix = {},
             StringRef IncludeSuffix = {});
  
    /// Get the detected GCC installation path suffix for the multi-arch
    /// target variant. Always starts with a '/', unless empty
    const std::string &gccSuffix() const {
      assert(GCCSuffix.empty() ||
             (StringRef(GCCSuffix).front() == '/' && GCCSuffix.size() > 1));
      return GCCSuffix;
    }
  
    /// Set the GCC installation path suffix.
    Multilib &gccSuffix(StringRef S);
  
    /// Get the detected os path suffix for the multi-arch
    /// target variant. Always starts with a '/', unless empty
    const std::string &osSuffix() const {
      assert(OSSuffix.empty() ||
             (StringRef(OSSuffix).front() == '/' && OSSuffix.size() > 1));
      return OSSuffix;
    }
  
    /// Set the os path suffix.
    Multilib &osSuffix(StringRef S);
  
    /// Get the include directory suffix. Always starts with a '/', unless
    /// empty
    const std::string &includeSuffix() const {
      assert(IncludeSuffix.empty() ||
             (StringRef(IncludeSuffix).front() == '/' && IncludeSuffix.size() > 1));
      return IncludeSuffix;
    }
  
    /// Set the include directory suffix
    Multilib &includeSuffix(StringRef S);
  
    /// Get the flags that indicate or contraindicate this multilib's use
    /// All elements begin with either '+' or '-'
    const flags_list &flags() const { return Flags; }
    flags_list &flags() { return Flags; }
  
    /// Add a flag to the flags list
    /// \p Flag must be a flag accepted by the driver with its leading '-' removed,
    ///     and replaced with either:
    ///       '-' which contraindicates using this multilib with that flag
    ///     or:
    ///       '+' which promotes using this multilib in the presence of that flag
    ///     otherwise '-print-multi-lib' will not emit them correctly.
    Multilib &flag(StringRef F) {
      assert(F.front() == '+' || F.front() == '-');
      Flags.push_back(F);
      return *this;
    }
  
    LLVM_DUMP_METHOD void dump() const;
    /// print summary of the Multilib
    void print(raw_ostream &OS) const;
  
    /// Check whether any of the 'against' flags contradict the 'for' flags.
    bool isValid() const;
  
    /// Check whether the default is selected
    bool isDefault() const
    { return GCCSuffix.empty() && OSSuffix.empty() && IncludeSuffix.empty(); }
  
    bool operator==(const Multilib &Other) const;
  };
  
  raw_ostream &operator<<(raw_ostream &OS, const Multilib &M);
  
  class MultilibSet {
  public:
    using multilib_list = std::vector<Multilib>;
    using iterator = multilib_list::iterator;
    using const_iterator = multilib_list::const_iterator;
    using IncludeDirsFunc =
        std::function<std::vector<std::string>(const Multilib &M)>;
    using FilterCallback = llvm::function_ref<bool(const Multilib &)>;
  
  private:
    multilib_list Multilibs;
    IncludeDirsFunc IncludeCallback;
    IncludeDirsFunc FilePathsCallback;
  
  public:
    MultilibSet() = default;
  
    /// Add an optional Multilib segment
    MultilibSet &Maybe(const Multilib &M);
  
    /// Add a set of mutually incompatible Multilib segments
    MultilibSet &Either(const Multilib &M1, const Multilib &M2);
    MultilibSet &Either(const Multilib &M1, const Multilib &M2,
                        const Multilib &M3);
    MultilibSet &Either(const Multilib &M1, const Multilib &M2,
                        const Multilib &M3, const Multilib &M4);
    MultilibSet &Either(const Multilib &M1, const Multilib &M2,
                        const Multilib &M3, const Multilib &M4,
                        const Multilib &M5);
    MultilibSet &Either(ArrayRef<Multilib> Ms);
  
    /// Filter out some subset of the Multilibs using a user defined callback
    MultilibSet &FilterOut(FilterCallback F);
  
    /// Filter out those Multilibs whose gccSuffix matches the given expression
    MultilibSet &FilterOut(const char *Regex);
  
    /// Add a completed Multilib to the set
    void push_back(const Multilib &M);
  
    /// Union this set of multilibs with another
    void combineWith(const MultilibSet &MS);
  
    /// Remove all of the multilibs from the set
    void clear() { Multilibs.clear(); }
  
    iterator begin() { return Multilibs.begin(); }
    const_iterator begin() const { return Multilibs.begin(); }
  
    iterator end() { return Multilibs.end(); }
    const_iterator end() const { return Multilibs.end(); }
  
    /// Pick the best multilib in the set, \returns false if none are compatible
    bool select(const Multilib::flags_list &Flags, Multilib &M) const;
  
    unsigned size() const { return Multilibs.size(); }
  
    LLVM_DUMP_METHOD void dump() const;
    void print(raw_ostream &OS) const;
  
    MultilibSet &setIncludeDirsCallback(IncludeDirsFunc F) {
      IncludeCallback = std::move(F);
      return *this;
    }
  
    const IncludeDirsFunc &includeDirsCallback() const { return IncludeCallback; }
  
    MultilibSet &setFilePathsCallback(IncludeDirsFunc F) {
      FilePathsCallback = std::move(F);
      return *this;
    }
  
    const IncludeDirsFunc &filePathsCallback() const { return FilePathsCallback; }
  
  private:
    /// Apply the filter to Multilibs and return the subset that remains
    static multilib_list filterCopy(FilterCallback F, const multilib_list &Ms);
  
    /// Apply the filter to the multilib_list, removing those that don't match
    static void filterInPlace(FilterCallback F, multilib_list &Ms);
  };
  
  raw_ostream &operator<<(raw_ostream &OS, const MultilibSet &MS);
  
  } // namespace driver
  } // namespace clang
  
  #endif // LLVM_CLANG_DRIVER_MULTILIB_H
  