1//===- llvm/Support/StringSaver.h -------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_SUPPORT_STRINGSAVER_H
10#define LLVM_SUPPORT_STRINGSAVER_H
11
12#include "llvm/ADT/DenseSet.h"
13#include "llvm/ADT/StringRef.h"
14#include "llvm/ADT/Twine.h"
15#include "llvm/Support/Allocator.h"
16
17namespace llvm {
18
19/// Saves strings in the provided stable storage and returns a
20/// StringRef with a stable character pointer.
21class StringSaver final {
22 BumpPtrAllocator &Alloc;
23
24public:
25 StringSaver(BumpPtrAllocator &Alloc) : Alloc(Alloc) {}
26
27 BumpPtrAllocator &getAllocator() const { return Alloc; }
28
29 // All returned strings are null-terminated: *save(S).end() == 0.
30 StringRef save(const char *S) { return save(S: StringRef(S)); }
31 StringRef save(StringRef S);
32 StringRef save(const Twine &S);
33 StringRef save(const std::string &S) { return save(S: StringRef(S)); }
34};
35
36/// Saves strings in the provided stable storage and returns a StringRef with a
37/// stable character pointer. Saving the same string yields the same StringRef.
38///
39/// Compared to StringSaver, it does more work but avoids saving the same string
40/// multiple times.
41///
42/// Compared to StringPool, it performs fewer allocations but doesn't support
43/// refcounting/deletion.
44class UniqueStringSaver final {
45 StringSaver Strings;
46 llvm::DenseSet<llvm::StringRef> Unique;
47
48public:
49 UniqueStringSaver(BumpPtrAllocator &Alloc) : Strings(Alloc) {}
50
51 // All returned strings are null-terminated: *save(S).end() == 0.
52 StringRef save(const char *S) { return save(S: StringRef(S)); }
53 StringRef save(StringRef S);
54 StringRef save(const Twine &S);
55 StringRef save(const std::string &S) { return save(S: StringRef(S)); }
56};
57
58} // namespace llvm
59#endif
60

source code of llvm/include/llvm/Support/StringSaver.h