1 //===-- ConstString.cpp -----------------------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "lldb/Utility/ConstString.h"
12 #include "lldb/Utility/Stream.h"
14 #include "llvm/ADT/StringMap.h"
15 #include "llvm/ADT/iterator.h"
16 #include "llvm/Support/Allocator.h"
17 #include "llvm/Support/DJB.h"
18 #include "llvm/Support/FormatProviders.h"
19 #include "llvm/Support/RWMutex.h"
20 #include "llvm/Support/Threading.h"
30 using namespace lldb_private;
34 typedef const char *StringPoolValueType;
35 typedef llvm::StringMap<StringPoolValueType, llvm::BumpPtrAllocator>
37 typedef llvm::StringMapEntry<StringPoolValueType> StringPoolEntryType;
39 static StringPoolEntryType &
40 GetStringMapEntryFromKeyData(const char *keyData) {
41 return StringPoolEntryType::GetStringMapEntryFromKeyData(keyData);
44 static size_t GetConstCStringLength(const char *ccstr) {
45 if (ccstr != nullptr) {
46 // Since the entry is read only, and we derive the entry entirely from
47 // the pointer, we don't need the lock.
48 const StringPoolEntryType &entry = GetStringMapEntryFromKeyData(ccstr);
49 return entry.getKey().size();
54 StringPoolValueType GetMangledCounterpart(const char *ccstr) const {
55 if (ccstr != nullptr) {
56 const uint8_t h = hash(llvm::StringRef(ccstr));
57 llvm::sys::SmartScopedReader<false> rlock(m_string_pools[h].m_mutex);
58 return GetStringMapEntryFromKeyData(ccstr).getValue();
63 bool SetMangledCounterparts(const char *key_ccstr, const char *value_ccstr) {
64 if (key_ccstr != nullptr && value_ccstr != nullptr) {
66 const uint8_t h = hash(llvm::StringRef(key_ccstr));
67 llvm::sys::SmartScopedWriter<false> wlock(m_string_pools[h].m_mutex);
68 GetStringMapEntryFromKeyData(key_ccstr).setValue(value_ccstr);
71 const uint8_t h = hash(llvm::StringRef(value_ccstr));
72 llvm::sys::SmartScopedWriter<false> wlock(m_string_pools[h].m_mutex);
73 GetStringMapEntryFromKeyData(value_ccstr).setValue(key_ccstr);
80 const char *GetConstCString(const char *cstr) {
82 return GetConstCStringWithLength(cstr, strlen(cstr));
86 const char *GetConstCStringWithLength(const char *cstr, size_t cstr_len) {
88 return GetConstCStringWithStringRef(llvm::StringRef(cstr, cstr_len));
92 const char *GetConstCStringWithStringRef(const llvm::StringRef &string_ref) {
93 if (string_ref.data()) {
94 const uint8_t h = hash(string_ref);
97 llvm::sys::SmartScopedReader<false> rlock(m_string_pools[h].m_mutex);
98 auto it = m_string_pools[h].m_string_map.find(string_ref);
99 if (it != m_string_pools[h].m_string_map.end())
100 return it->getKeyData();
103 llvm::sys::SmartScopedWriter<false> wlock(m_string_pools[h].m_mutex);
104 StringPoolEntryType &entry =
106 .m_string_map.insert(std::make_pair(string_ref, nullptr))
108 return entry.getKeyData();
114 GetConstCStringAndSetMangledCounterPart(llvm::StringRef demangled,
115 const char *mangled_ccstr) {
116 const char *demangled_ccstr = nullptr;
119 const uint8_t h = hash(demangled);
120 llvm::sys::SmartScopedWriter<false> wlock(m_string_pools[h].m_mutex);
122 // Make or update string pool entry with the mangled counterpart
123 StringPool &map = m_string_pools[h].m_string_map;
124 StringPoolEntryType &entry = *map.try_emplace(demangled).first;
126 entry.second = mangled_ccstr;
128 // Extract the const version of the demangled_cstr
129 demangled_ccstr = entry.getKeyData();
133 // Now assign the demangled const string as the counterpart of the
134 // mangled const string...
135 const uint8_t h = hash(llvm::StringRef(mangled_ccstr));
136 llvm::sys::SmartScopedWriter<false> wlock(m_string_pools[h].m_mutex);
137 GetStringMapEntryFromKeyData(mangled_ccstr).setValue(demangled_ccstr);
140 // Return the constant demangled C string
141 return demangled_ccstr;
144 const char *GetConstTrimmedCStringWithLength(const char *cstr,
146 if (cstr != nullptr) {
147 const size_t trimmed_len = std::min<size_t>(strlen(cstr), cstr_len);
148 return GetConstCStringWithLength(cstr, trimmed_len);
153 //------------------------------------------------------------------
154 // Return the size in bytes that this object and any items in its collection
155 // of uniqued strings + data count values takes in memory.
156 //------------------------------------------------------------------
157 size_t MemorySize() const {
158 size_t mem_size = sizeof(Pool);
159 for (const auto &pool : m_string_pools) {
160 llvm::sys::SmartScopedReader<false> rlock(pool.m_mutex);
161 for (const auto &entry : pool.m_string_map)
162 mem_size += sizeof(StringPoolEntryType) + entry.getKey().size();
168 uint8_t hash(const llvm::StringRef &s) const {
169 uint32_t h = llvm::djbHash(s);
170 return ((h >> 24) ^ (h >> 16) ^ (h >> 8) ^ h) & 0xff;
174 mutable llvm::sys::SmartRWMutex<false> m_mutex;
175 StringPool m_string_map;
178 std::array<PoolEntry, 256> m_string_pools;
181 //----------------------------------------------------------------------
182 // Frameworks and dylibs aren't supposed to have global C++ initializers so we
183 // hide the string pool in a static function so that it will get initialized on
184 // the first call to this static function.
186 // Note, for now we make the string pool a pointer to the pool, because we
187 // can't guarantee that some objects won't get destroyed after the global
188 // destructor chain is run, and trying to make sure no destructors touch
189 // ConstStrings is difficult. So we leak the pool instead.
190 //----------------------------------------------------------------------
191 static Pool &StringPool() {
192 static llvm::once_flag g_pool_initialization_flag;
193 static Pool *g_string_pool = nullptr;
195 llvm::call_once(g_pool_initialization_flag,
196 []() { g_string_pool = new Pool(); });
198 return *g_string_pool;
201 ConstString::ConstString(const char *cstr)
202 : m_string(StringPool().GetConstCString(cstr)) {}
204 ConstString::ConstString(const char *cstr, size_t cstr_len)
205 : m_string(StringPool().GetConstCStringWithLength(cstr, cstr_len)) {}
207 ConstString::ConstString(const llvm::StringRef &s)
208 : m_string(StringPool().GetConstCStringWithLength(s.data(), s.size())) {}
210 bool ConstString::operator<(const ConstString &rhs) const {
211 if (m_string == rhs.m_string)
214 llvm::StringRef lhs_string_ref(GetStringRef());
215 llvm::StringRef rhs_string_ref(rhs.GetStringRef());
217 // If both have valid C strings, then return the comparison
218 if (lhs_string_ref.data() && rhs_string_ref.data())
219 return lhs_string_ref < rhs_string_ref;
221 // Else one of them was nullptr, so if LHS is nullptr then it is less than
222 return lhs_string_ref.data() == nullptr;
225 Stream &lldb_private::operator<<(Stream &s, const ConstString &str) {
226 const char *cstr = str.GetCString();
233 size_t ConstString::GetLength() const {
234 return Pool::GetConstCStringLength(m_string);
237 bool ConstString::Equals(const ConstString &lhs, const ConstString &rhs,
238 const bool case_sensitive) {
239 if (lhs.m_string == rhs.m_string)
242 // Since the pointers weren't equal, and identical ConstStrings always have
243 // identical pointers, the result must be false for case sensitive equality
248 // perform case insensitive equality test
249 llvm::StringRef lhs_string_ref(lhs.GetStringRef());
250 llvm::StringRef rhs_string_ref(rhs.GetStringRef());
251 return lhs_string_ref.equals_lower(rhs_string_ref);
254 int ConstString::Compare(const ConstString &lhs, const ConstString &rhs,
255 const bool case_sensitive) {
256 // If the iterators are the same, this is the same string
257 const char *lhs_cstr = lhs.m_string;
258 const char *rhs_cstr = rhs.m_string;
259 if (lhs_cstr == rhs_cstr)
261 if (lhs_cstr && rhs_cstr) {
262 llvm::StringRef lhs_string_ref(lhs.GetStringRef());
263 llvm::StringRef rhs_string_ref(rhs.GetStringRef());
265 if (case_sensitive) {
266 return lhs_string_ref.compare(rhs_string_ref);
268 return lhs_string_ref.compare_lower(rhs_string_ref);
273 return +1; // LHS isn't nullptr but RHS is
275 return -1; // LHS is nullptr but RHS isn't
278 void ConstString::Dump(Stream *s, const char *fail_value) const {
280 const char *cstr = AsCString(fail_value);
286 void ConstString::DumpDebug(Stream *s) const {
287 const char *cstr = GetCString();
288 size_t cstr_len = GetLength();
289 // Only print the parens if we have a non-nullptr string
290 const char *parens = cstr ? "\"" : "";
291 s->Printf("%*p: ConstString, string = %s%s%s, length = %" PRIu64,
292 static_cast<int>(sizeof(void *) * 2),
293 static_cast<const void *>(this), parens, cstr, parens,
294 static_cast<uint64_t>(cstr_len));
297 void ConstString::SetCString(const char *cstr) {
298 m_string = StringPool().GetConstCString(cstr);
301 void ConstString::SetString(const llvm::StringRef &s) {
302 m_string = StringPool().GetConstCStringWithLength(s.data(), s.size());
305 void ConstString::SetStringWithMangledCounterpart(llvm::StringRef demangled,
306 const ConstString &mangled) {
307 m_string = StringPool().GetConstCStringAndSetMangledCounterPart(
308 demangled, mangled.m_string);
311 bool ConstString::GetMangledCounterpart(ConstString &counterpart) const {
312 counterpart.m_string = StringPool().GetMangledCounterpart(m_string);
313 return (bool)counterpart;
316 void ConstString::SetCStringWithLength(const char *cstr, size_t cstr_len) {
317 m_string = StringPool().GetConstCStringWithLength(cstr, cstr_len);
320 void ConstString::SetTrimmedCStringWithLength(const char *cstr,
322 m_string = StringPool().GetConstTrimmedCStringWithLength(cstr, cstr_len);
325 size_t ConstString::StaticMemorySize() {
326 // Get the size of the static string pool
327 return StringPool().MemorySize();
330 void llvm::format_provider<ConstString>::format(const ConstString &CS,
331 llvm::raw_ostream &OS,
332 llvm::StringRef Options) {
333 format_provider<StringRef>::format(CS.AsCString(), OS, Options);