| 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 | |
| 17 | namespace llvm { |
| 18 | |
| 19 | /// Saves strings in the provided stable storage and returns a |
| 20 | /// StringRef with a stable character pointer. |
| 21 | class StringSaver final { |
| 22 | BumpPtrAllocator &Alloc; |
| 23 | |
| 24 | public: |
| 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) { return save(S: StringRef(S.str())); } |
| 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. |
| 44 | class UniqueStringSaver final { |
| 45 | StringSaver Strings; |
| 46 | llvm::DenseSet<llvm::StringRef> Unique; |
| 47 | |
| 48 | public: |
| 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) { return save(S: StringRef(S.str())); } |
| 55 | StringRef save(const std::string &S) { return save(S: StringRef(S)); } |
| 56 | }; |
| 57 | |
| 58 | } // namespace llvm |
| 59 | #endif |
| 60 |