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/StringExtras.h"
15 #include "llvm/ADT/StringMap.h"
16 #include "llvm/ADT/iterator.h" // for iterator_facade_base
17 #include "llvm/Support/Allocator.h" // for BumpPtrAllocator
18 #include "llvm/Support/FormatProviders.h" // for format_provider
19 #include "llvm/Support/RWMutex.h"
20 #include "llvm/Support/Threading.h"
22 #include <algorithm> // for min
24 #include <utility> // for make_pair, pair
26 #include <inttypes.h> // for PRIu64
27 #include <stdint.h> // for uint8_t, uint32_t, uint64_t
28 #include <string.h> // for size_t, strlen
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 the
47 // 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(const char *demangled_cstr,
115 const char *mangled_ccstr) {
116 if (demangled_cstr != nullptr) {
117 const char *demangled_ccstr = nullptr;
120 llvm::StringRef string_ref(demangled_cstr);
121 const uint8_t h = hash(string_ref);
122 llvm::sys::SmartScopedWriter<false> wlock(m_string_pools[h].m_mutex);
124 // Make string pool entry with the mangled counterpart already set
125 StringPoolEntryType &entry =
127 .m_string_map.insert(std::make_pair(string_ref, mangled_ccstr))
130 // Extract the const version of the demangled_cstr
131 demangled_ccstr = entry.getKeyData();
135 // Now assign the demangled const string as the counterpart of the
136 // mangled const string...
137 const uint8_t h = hash(llvm::StringRef(mangled_ccstr));
138 llvm::sys::SmartScopedWriter<false> wlock(m_string_pools[h].m_mutex);
139 GetStringMapEntryFromKeyData(mangled_ccstr).setValue(demangled_ccstr);
142 // Return the constant demangled C string
143 return demangled_ccstr;
148 const char *GetConstTrimmedCStringWithLength(const char *cstr,
150 if (cstr != nullptr) {
151 const size_t trimmed_len = std::min<size_t>(strlen(cstr), cstr_len);
152 return GetConstCStringWithLength(cstr, trimmed_len);
157 //------------------------------------------------------------------
158 // Return the size in bytes that this object and any items in its
159 // collection of uniqued strings + data count values takes in
161 //------------------------------------------------------------------
162 size_t MemorySize() const {
163 size_t mem_size = sizeof(Pool);
164 for (const auto &pool : m_string_pools) {
165 llvm::sys::SmartScopedReader<false> rlock(pool.m_mutex);
166 for (const auto &entry : pool.m_string_map)
167 mem_size += sizeof(StringPoolEntryType) + entry.getKey().size();
173 uint8_t hash(const llvm::StringRef &s) const {
174 uint32_t h = llvm::HashString(s);
175 return ((h >> 24) ^ (h >> 16) ^ (h >> 8) ^ h) & 0xff;
179 mutable llvm::sys::SmartRWMutex<false> m_mutex;
180 StringPool m_string_map;
183 std::array<PoolEntry, 256> m_string_pools;
186 //----------------------------------------------------------------------
187 // Frameworks and dylibs aren't supposed to have global C++
188 // initializers so we hide the string pool in a static function so
189 // that it will get initialized on the first call to this static
192 // Note, for now we make the string pool a pointer to the pool, because
193 // we can't guarantee that some objects won't get destroyed after the
194 // global destructor chain is run, and trying to make sure no destructors
195 // touch ConstStrings is difficult. So we leak the pool instead.
196 //----------------------------------------------------------------------
197 static Pool &StringPool() {
198 static llvm::once_flag g_pool_initialization_flag;
199 static Pool *g_string_pool = nullptr;
201 llvm::call_once(g_pool_initialization_flag,
202 []() { g_string_pool = new Pool(); });
204 return *g_string_pool;
207 ConstString::ConstString(const char *cstr)
208 : m_string(StringPool().GetConstCString(cstr)) {}
210 ConstString::ConstString(const char *cstr, size_t cstr_len)
211 : m_string(StringPool().GetConstCStringWithLength(cstr, cstr_len)) {}
213 ConstString::ConstString(const llvm::StringRef &s)
214 : m_string(StringPool().GetConstCStringWithLength(s.data(), s.size())) {}
216 bool ConstString::operator<(const ConstString &rhs) const {
217 if (m_string == rhs.m_string)
220 llvm::StringRef lhs_string_ref(GetStringRef());
221 llvm::StringRef rhs_string_ref(rhs.GetStringRef());
223 // If both have valid C strings, then return the comparison
224 if (lhs_string_ref.data() && rhs_string_ref.data())
225 return lhs_string_ref < rhs_string_ref;
227 // Else one of them was nullptr, so if LHS is nullptr then it is less than
228 return lhs_string_ref.data() == nullptr;
231 Stream &lldb_private::operator<<(Stream &s, const ConstString &str) {
232 const char *cstr = str.GetCString();
239 size_t ConstString::GetLength() const {
240 return Pool::GetConstCStringLength(m_string);
243 bool ConstString::Equals(const ConstString &lhs, const ConstString &rhs,
244 const bool case_sensitive) {
245 if (lhs.m_string == rhs.m_string)
248 // Since the pointers weren't equal, and identical ConstStrings always have
249 // identical pointers,
250 // the result must be false for case sensitive equality test.
254 // perform case insensitive equality test
255 llvm::StringRef lhs_string_ref(lhs.GetStringRef());
256 llvm::StringRef rhs_string_ref(rhs.GetStringRef());
257 return lhs_string_ref.equals_lower(rhs_string_ref);
260 int ConstString::Compare(const ConstString &lhs, const ConstString &rhs,
261 const bool case_sensitive) {
262 // If the iterators are the same, this is the same string
263 const char *lhs_cstr = lhs.m_string;
264 const char *rhs_cstr = rhs.m_string;
265 if (lhs_cstr == rhs_cstr)
267 if (lhs_cstr && rhs_cstr) {
268 llvm::StringRef lhs_string_ref(lhs.GetStringRef());
269 llvm::StringRef rhs_string_ref(rhs.GetStringRef());
271 if (case_sensitive) {
272 return lhs_string_ref.compare(rhs_string_ref);
274 return lhs_string_ref.compare_lower(rhs_string_ref);
279 return +1; // LHS isn't nullptr but RHS is
281 return -1; // LHS is nullptr but RHS isn't
284 void ConstString::Dump(Stream *s, const char *fail_value) const {
286 const char *cstr = AsCString(fail_value);
292 void ConstString::DumpDebug(Stream *s) const {
293 const char *cstr = GetCString();
294 size_t cstr_len = GetLength();
295 // Only print the parens if we have a non-nullptr string
296 const char *parens = cstr ? "\"" : "";
297 s->Printf("%*p: ConstString, string = %s%s%s, length = %" PRIu64,
298 static_cast<int>(sizeof(void *) * 2),
299 static_cast<const void *>(this), parens, cstr, parens,
300 static_cast<uint64_t>(cstr_len));
303 void ConstString::SetCString(const char *cstr) {
304 m_string = StringPool().GetConstCString(cstr);
307 void ConstString::SetString(const llvm::StringRef &s) {
308 m_string = StringPool().GetConstCStringWithLength(s.data(), s.size());
311 void ConstString::SetCStringWithMangledCounterpart(const char *demangled,
312 const ConstString &mangled) {
313 m_string = StringPool().GetConstCStringAndSetMangledCounterPart(
314 demangled, mangled.m_string);
317 bool ConstString::GetMangledCounterpart(ConstString &counterpart) const {
318 counterpart.m_string = StringPool().GetMangledCounterpart(m_string);
319 return (bool)counterpart;
322 void ConstString::SetCStringWithLength(const char *cstr, size_t cstr_len) {
323 m_string = StringPool().GetConstCStringWithLength(cstr, cstr_len);
326 void ConstString::SetTrimmedCStringWithLength(const char *cstr,
328 m_string = StringPool().GetConstTrimmedCStringWithLength(cstr, cstr_len);
331 size_t ConstString::StaticMemorySize() {
332 // Get the size of the static string pool
333 return StringPool().MemorySize();
336 void llvm::format_provider<ConstString>::format(const ConstString &CS,
337 llvm::raw_ostream &OS,
338 llvm::StringRef Options) {
339 format_provider<StringRef>::format(CS.AsCString(), OS, Options);