LibraryOptionsContext.h

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//===----------------------------------------------------------------------===//
//
// 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_SUPPORT_LIBRARYOPTIONSCONTEXT_H
#define LLVM_SUPPORT_LIBRARYOPTIONSCONTEXT_H
 
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Compiler.h"
 
namespace llvm {
 
class Error;
 
namespace cl {
 
class LibraryOptions;
 
// The library options of one compilation context, such as an LLVMContext.
// Libraries declared with perContext read their options here.
class LLVM_ABI LibraryOptionsContext {
public:
  // Replaces the library options with Other's by replaying its arguments.
  //
  // A library's values start as a copy of its global(), which may refer to
  // strings that ResetAllOptionOccurrences frees.
  // Indexing libraries registered since the last parse is not thread-safe.
  void assign(const LibraryOptionsContext &Other);
 
  // Parses the option of L that Args[0] spells, keeping the other values.
  Error parse(LibraryOptions &L, ArrayRef<const char *> Args,
              unsigned &Consumed);
 
  // The arguments assigned so far.
  ArrayRef<const char *> args() const { return SavedArgs; }
 
  // T's values, or T::Global if there are none.
  template <typename T> const T &get() const {
    if (const void *Opts = Values.lookup(&T::Global))
      return *static_cast<const T *>(Opts);
    // TODO: Return the defaults once cl::ParseCommandLineOptions callers have
    // migrated to parseCommandLineOptions and no longer set T::Global.
    return T::Global;
  }
 
  // C's values of T, or T::Global if C is null.
  template <typename T> static const T &get(const LibraryOptionsContext *C) {
    return C ? C->get<T>() : T::Global;
  }
 
private:
  DenseMap<const void *, void *> Values;
  SmallVector<const char *, 0> SavedArgs;
  BumpPtrAllocator Alloc;
};
 
} // namespace cl
} // namespace llvm
 
#endif // LLVM_SUPPORT_LIBRARYOPTIONSCONTEXT_H