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//===- Memory.h -------------------------------------------------*- C++ -*-===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines arena allocators.
//
// Almost all large objects, such as files, sections or symbols, are
// used for the entire lifetime of the linker once they are created.
// This usage characteristic makes arena allocator an attractive choice
// where the entire linker is one arena. With an arena, newly created
// objects belong to the arena and freed all at once when everything is done.
// Arena allocators are efficient and easy to understand.
// Most objects are allocated using the arena allocators defined by this file.
//
// If you edit this file, please edit COFF/Memory.h too.
//
//===----------------------------------------------------------------------===//
#ifndef LLD_ELF_MEMORY_H
#define LLD_ELF_MEMORY_H
#include "llvm/Support/Allocator.h"
#include "llvm/Support/StringSaver.h"
#include <vector>
namespace lld {
namespace elf {
// Use this arena if your object doesn't have a destructor.
extern llvm::BumpPtrAllocator BAlloc;
extern llvm::StringSaver Saver;
// These two classes are hack to keep track of all
// SpecificBumpPtrAllocator instances.
struct SpecificAllocBase {
SpecificAllocBase() { Instances.push_back(this); }
virtual ~SpecificAllocBase() = default;
virtual void reset() = 0;
static std::vector<SpecificAllocBase *> Instances;
};
template <class T> struct SpecificAlloc : public SpecificAllocBase {
void reset() override { Alloc.DestroyAll(); }
llvm::SpecificBumpPtrAllocator<T> Alloc;
};
// Use this arena if your object has a destructor.
// Your destructor will be invoked from freeArena().
template <typename T, typename... U> T *make(U &&... Args) {
static SpecificAlloc<T> Alloc;
return new (Alloc.Alloc.Allocate()) T(std::forward<U>(Args)...);
}
inline void freeArena() {
for (SpecificAllocBase *Alloc : SpecificAllocBase::Instances)
Alloc->reset();
BAlloc.Reset();
}
}
}
#endif
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