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