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NSString.cpp
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1//===-- NSString.cpp ------------------------------------------------------===//
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#include "NSString.h"
10
16#include "lldb/Target/Target.h"
19#include "lldb/Utility/Endian.h"
20#include "lldb/Utility/Status.h"
21#include "lldb/Utility/Stream.h"
22
23using namespace lldb;
24using namespace lldb_private;
25using namespace lldb_private::formatters;
26
27std::map<ConstString, CXXFunctionSummaryFormat::Callback> &
29 static std::map<ConstString, CXXFunctionSummaryFormat::Callback> g_map;
30 return g_map;
31}
32
34 ValueObject &valobj, Stream &stream,
35 const TypeSummaryOptions &summary_options) {
36 static constexpr llvm::StringLiteral g_TypeHint("NSString");
37
38 ProcessSP process_sp = valobj.GetProcessSP();
39 if (!process_sp)
40 return false;
41
42 ObjCLanguageRuntime *runtime = ObjCLanguageRuntime::Get(*process_sp);
43
44 if (!runtime)
45 return false;
46
48 runtime->GetClassDescriptor(valobj));
49
50 if (!descriptor.get() || !descriptor->IsValid())
51 return false;
52
53 uint32_t ptr_size = process_sp->GetAddressByteSize();
54
55 lldb::addr_t valobj_addr = valobj.GetValueAsUnsigned(0);
56
57 if (!valobj_addr)
58 return false;
59
60 ConstString class_name_cs = descriptor->GetClassName();
61 llvm::StringRef class_name = class_name_cs.GetStringRef();
62
63 if (class_name.empty())
64 return false;
65
66 bool is_tagged_ptr = class_name == "NSTaggedPointerString" &&
67 descriptor->GetTaggedPointerInfo();
68 // for a tagged pointer, the descriptor has everything we need
69 if (is_tagged_ptr)
70 return NSTaggedString_SummaryProvider(valobj, descriptor, stream,
71 summary_options);
72
73 auto &additionals_map(NSString_Additionals::GetAdditionalSummaries());
74 auto iter = additionals_map.find(class_name_cs), end = additionals_map.end();
75 if (iter != end)
76 return iter->second(valobj, stream, summary_options);
77
78 // if not a tagged pointer that we know about, try the normal route
79 uint64_t info_bits_location = valobj_addr + ptr_size;
80 if (process_sp->GetByteOrder() != lldb::eByteOrderLittle)
81 info_bits_location += 3;
82
84
85 uint8_t info_bits = process_sp->ReadUnsignedIntegerFromMemory(
86 info_bits_location, 1, 0, error);
87 if (error.Fail())
88 return false;
89
90 bool is_mutable = (info_bits & 1) == 1;
91 bool is_inline = (info_bits & 0x60) == 0;
92 bool has_explicit_length = (info_bits & (1 | 4)) != 4;
93 bool is_unicode = (info_bits & 0x10) == 0x10;
94 bool is_path_store = class_name == "NSPathStore2";
95 bool has_null = (info_bits & 8) == 8;
96
97 size_t explicit_length = 0;
98 if (!has_null && has_explicit_length && !is_path_store) {
99 lldb::addr_t explicit_length_offset = 2 * ptr_size;
100 if (is_mutable && !is_inline)
101 explicit_length_offset =
102 explicit_length_offset + ptr_size; // notInlineMutable.length;
103 else if (is_inline)
104 explicit_length = explicit_length + 0; // inline1.length;
105 else if (!is_inline && !is_mutable)
106 explicit_length_offset =
107 explicit_length_offset + ptr_size; // notInlineImmutable1.length;
108 else
109 explicit_length_offset = 0;
110
111 if (explicit_length_offset) {
112 explicit_length_offset = valobj_addr + explicit_length_offset;
113 explicit_length = process_sp->ReadUnsignedIntegerFromMemory(
114 explicit_length_offset, 4, 0, error);
115 }
116 }
117
118 const llvm::StringSet<> supported_string_classes = {
119 "NSString", "CFMutableStringRef",
120 "CFStringRef", "__NSCFConstantString",
121 "__NSCFString", "NSCFConstantString",
122 "NSCFString", "NSPathStore2"};
123 if (supported_string_classes.count(class_name) == 0) {
124 // not one of us - but tell me class name
125 stream.Printf("class name = %s", class_name_cs.GetCString());
126 return true;
127 }
128
129 llvm::StringRef prefix, suffix;
130 if (Language *language = Language::FindPlugin(summary_options.GetLanguage()))
131 std::tie(prefix, suffix) = language->GetFormatterPrefixSuffix(g_TypeHint);
132
134 options.SetPrefixToken(prefix.str());
135 options.SetSuffixToken(suffix.str());
136
137 if (is_mutable) {
138 uint64_t location = 2 * ptr_size + valobj_addr;
139 location = process_sp->ReadPointerFromMemory(location, error);
140 if (error.Fail())
141 return false;
142 if (has_explicit_length && is_unicode) {
143 options.SetLocation(location);
144 options.SetTargetSP(valobj.GetTargetSP());
145 options.SetStream(&stream);
146 options.SetQuote('"');
147 options.SetSourceSize(explicit_length);
148 options.SetHasSourceSize(has_explicit_length);
149 options.SetNeedsZeroTermination(false);
150 options.SetIgnoreMaxLength(summary_options.GetCapping() ==
151 TypeSummaryCapping::eTypeSummaryUncapped);
152 options.SetBinaryZeroIsTerminator(false);
154 StringPrinter::StringElementType::UTF16>(options);
155 } else {
156 options.SetLocation(location + 1);
157 options.SetTargetSP(valobj.GetTargetSP());
158 options.SetStream(&stream);
159 options.SetSourceSize(explicit_length);
160 options.SetHasSourceSize(has_explicit_length);
161 options.SetNeedsZeroTermination(false);
162 options.SetIgnoreMaxLength(summary_options.GetCapping() ==
163 TypeSummaryCapping::eTypeSummaryUncapped);
164 options.SetBinaryZeroIsTerminator(false);
166 StringPrinter::StringElementType::ASCII>(options);
167 }
168 } else if (is_inline && has_explicit_length && !is_unicode &&
169 !is_path_store && !is_mutable) {
170 uint64_t location = 3 * ptr_size + valobj_addr;
171
172 options.SetLocation(location);
173 options.SetTargetSP(valobj.GetTargetSP());
174 options.SetStream(&stream);
175 options.SetQuote('"');
176 options.SetSourceSize(explicit_length);
177 options.SetHasSourceSize(has_explicit_length);
178 options.SetIgnoreMaxLength(summary_options.GetCapping() ==
179 TypeSummaryCapping::eTypeSummaryUncapped);
181 StringPrinter::StringElementType::ASCII>(options);
182 } else if (is_unicode) {
183 uint64_t location = valobj_addr + 2 * ptr_size;
184 if (is_inline) {
185 if (!has_explicit_length) {
186 return false;
187 } else
188 location += ptr_size;
189 } else {
190 location = process_sp->ReadPointerFromMemory(location, error);
191 if (error.Fail())
192 return false;
193 }
194 options.SetLocation(location);
195 options.SetTargetSP(valobj.GetTargetSP());
196 options.SetStream(&stream);
197 options.SetQuote('"');
198 options.SetSourceSize(explicit_length);
199 options.SetHasSourceSize(has_explicit_length);
200 options.SetNeedsZeroTermination(!has_explicit_length);
201 options.SetIgnoreMaxLength(summary_options.GetCapping() ==
202 TypeSummaryCapping::eTypeSummaryUncapped);
203 options.SetBinaryZeroIsTerminator(!has_explicit_length);
205 StringPrinter::StringElementType::UTF16>(options);
206 } else if (is_path_store) {
207 // _lengthAndRefCount is the first ivar of NSPathStore2 (after the isa).
208 uint64_t length_ivar_offset = 1 * ptr_size;
209 CompilerType length_type = valobj.GetCompilerType().GetBasicTypeFromAST(
211 ValueObjectSP length_valobj_sp =
212 valobj.GetSyntheticChildAtOffset(length_ivar_offset, length_type, true,
213 ConstString("_lengthAndRefCount"));
214 if (!length_valobj_sp)
215 return false;
216 // Get the length out of _lengthAndRefCount.
217 explicit_length = length_valobj_sp->GetValueAsUnsigned(0) >> 20;
218 lldb::addr_t location = valobj.GetValueAsUnsigned(0) + ptr_size + 4;
219
220 options.SetLocation(location);
221 options.SetTargetSP(valobj.GetTargetSP());
222 options.SetStream(&stream);
223 options.SetQuote('"');
224 options.SetSourceSize(explicit_length);
225 options.SetHasSourceSize(has_explicit_length);
226 options.SetNeedsZeroTermination(!has_explicit_length);
227 options.SetIgnoreMaxLength(summary_options.GetCapping() ==
228 TypeSummaryCapping::eTypeSummaryUncapped);
229 options.SetBinaryZeroIsTerminator(!has_explicit_length);
231 StringPrinter::StringElementType::UTF16>(options);
232 } else if (is_inline) {
233 uint64_t location = valobj_addr + 2 * ptr_size;
234 if (!has_explicit_length) {
235 // in this kind of string, the byte before the string content is a length
236 // byte so let's try and use it to handle the embedded NUL case
238 explicit_length =
239 process_sp->ReadUnsignedIntegerFromMemory(location, 1, 0, error);
240 has_explicit_length = !(error.Fail() || explicit_length == 0);
241 location++;
242 }
243 options.SetLocation(location);
244 options.SetTargetSP(valobj.GetTargetSP());
245 options.SetStream(&stream);
246 options.SetSourceSize(explicit_length);
247 options.SetHasSourceSize(has_explicit_length);
248 options.SetNeedsZeroTermination(!has_explicit_length);
249 options.SetIgnoreMaxLength(summary_options.GetCapping() ==
250 TypeSummaryCapping::eTypeSummaryUncapped);
251 options.SetBinaryZeroIsTerminator(!has_explicit_length);
252 if (has_explicit_length)
254 StringPrinter::StringElementType::UTF8>(options);
255 else
257 StringPrinter::StringElementType::ASCII>(options);
258 } else {
259 uint64_t location = valobj_addr + 2 * ptr_size;
260 location = process_sp->ReadPointerFromMemory(location, error);
261 if (error.Fail())
262 return false;
263 if (has_explicit_length && !has_null)
264 explicit_length++; // account for the fact that there is no NULL and we
265 // need to have one added
266 options.SetLocation(location);
267 options.SetTargetSP(valobj.GetTargetSP());
268 options.SetStream(&stream);
269 options.SetSourceSize(explicit_length);
270 options.SetHasSourceSize(has_explicit_length);
271 options.SetIgnoreMaxLength(summary_options.GetCapping() ==
272 TypeSummaryCapping::eTypeSummaryUncapped);
274 StringPrinter::StringElementType::ASCII>(options);
275 }
276}
277
279 ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
280 TargetSP target_sp(valobj.GetTargetSP());
281 if (!target_sp)
282 return false;
283 uint32_t addr_size = target_sp->GetArchitecture().GetAddressByteSize();
284 uint64_t pointer_value = valobj.GetValueAsUnsigned(0);
285 if (!pointer_value)
286 return false;
287 pointer_value += addr_size;
288 CompilerType type(valobj.GetCompilerType());
289 ExecutionContext exe_ctx(target_sp, false);
291 "string_ptr", pointer_value, exe_ctx, type));
292 if (!child_ptr_sp)
293 return false;
294 DataExtractor data;
296 child_ptr_sp->GetData(data, error);
297 if (error.Fail())
298 return false;
299 ValueObjectSP child_sp(child_ptr_sp->CreateValueObjectFromData(
300 "string_data", data, exe_ctx, type));
301 child_sp->GetValueAsUnsigned(0);
302 if (child_sp)
303 return NSStringSummaryProvider(*child_sp, stream, options);
304 return false;
305}
306
308 ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
309 return NSAttributedStringSummaryProvider(valobj, stream, options);
310}
311
314 Stream &stream, const TypeSummaryOptions &summary_options) {
315 static constexpr llvm::StringLiteral g_TypeHint("NSString");
316
317 if (!descriptor)
318 return false;
319 uint64_t len_bits = 0, data_bits = 0;
320 if (!descriptor->GetTaggedPointerInfo(&len_bits, &data_bits, nullptr))
321 return false;
322
323 static const int g_MaxNonBitmaskedLen = 7; // TAGGED_STRING_UNPACKED_MAXLEN
324 static const int g_SixbitMaxLen = 9;
325 static const int g_fiveBitMaxLen = 11;
326
327 static const char *sixBitToCharLookup = "eilotrm.apdnsIc ufkMShjTRxgC4013"
328 "bDNvwyUL2O856P-B79AFKEWV_zGJ/HYX";
329
330 if (len_bits > g_fiveBitMaxLen)
331 return false;
332
333 llvm::StringRef prefix, suffix;
334 if (Language *language = Language::FindPlugin(summary_options.GetLanguage()))
335 std::tie(prefix, suffix) = language->GetFormatterPrefixSuffix(g_TypeHint);
336
337 // this is a fairly ugly trick - pretend that the numeric value is actually a
338 // char* this works under a few assumptions: little endian architecture
339 // sizeof(uint64_t) > g_MaxNonBitmaskedLen
340 if (len_bits <= g_MaxNonBitmaskedLen) {
341 stream << prefix;
342 stream.Printf("\"%s\"", (const char *)&data_bits);
343 stream << suffix;
344 return true;
345 }
346
347 // if the data is bitmasked, we need to actually process the bytes
348 uint8_t bitmask = 0;
349 uint8_t shift_offset = 0;
350
351 if (len_bits <= g_SixbitMaxLen) {
352 bitmask = 0x03f;
353 shift_offset = 6;
354 } else {
355 bitmask = 0x01f;
356 shift_offset = 5;
357 }
358
359 std::vector<uint8_t> bytes;
360 bytes.resize(len_bits);
361 for (; len_bits > 0; data_bits >>= shift_offset, --len_bits) {
362 uint8_t packed = data_bits & bitmask;
363 bytes.insert(bytes.begin(), sixBitToCharLookup[packed]);
364 }
365
366 stream << prefix;
367 stream.Printf("\"%s\"", &bytes[0]);
368 stream << suffix;
369 return true;
370}
static llvm::raw_ostream & error(Stream &strm)
Generic representation of a type in a programming language.
Definition: CompilerType.h:36
CompilerType GetBasicTypeFromAST(lldb::BasicType basic_type) const
Create related types using the current type's AST.
A uniqued constant string class.
Definition: ConstString.h:40
llvm::StringRef GetStringRef() const
Get the string value as a llvm::StringRef.
Definition: ConstString.h:197
const char * GetCString() const
Get the string value as a C string.
Definition: ConstString.h:216
An data extractor class.
Definition: DataExtractor.h:48
"lldb/Target/ExecutionContext.h" A class that contains an execution context.
static Language * FindPlugin(lldb::LanguageType language)
Definition: Language.cpp:84
std::shared_ptr< ClassDescriptor > ClassDescriptorSP
static ObjCLanguageRuntime * Get(Process &process)
virtual ClassDescriptorSP GetClassDescriptor(ValueObject &in_value)
An error handling class.
Definition: Status.h:44
A stream class that can stream formatted output to a file.
Definition: Stream.h:28
size_t Printf(const char *format,...) __attribute__((format(printf
Output printf formatted output to the stream.
Definition: Stream.cpp:134
lldb::LanguageType GetLanguage() const
Definition: TypeSummary.cpp:31
lldb::TypeSummaryCapping GetCapping() const
Definition: TypeSummary.cpp:33
CompilerType GetCompilerType()
Definition: ValueObject.h:352
lldb::ProcessSP GetProcessSP() const
Definition: ValueObject.h:338
virtual lldb::ValueObjectSP GetSyntheticChildAtOffset(uint32_t offset, const CompilerType &type, bool can_create, ConstString name_const_str=ConstString())
static lldb::ValueObjectSP CreateValueObjectFromAddress(llvm::StringRef name, uint64_t address, const ExecutionContext &exe_ctx, CompilerType type, bool do_deref=true)
Given an address either create a value object containing the value at that address,...
virtual uint64_t GetValueAsUnsigned(uint64_t fail_value, bool *success=nullptr)
lldb::TargetSP GetTargetSP() const
Definition: ValueObject.h:334
static std::map< ConstString, CXXFunctionSummaryFormat::Callback > & GetAdditionalSummaries()
Definition: NSString.cpp:28
static bool ReadStringAndDumpToStream(const ReadStringAndDumpToStreamOptions &options)
bool NSMutableAttributedStringSummaryProvider(ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options)
Definition: NSString.cpp:307
bool NSAttributedStringSummaryProvider(ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options)
Definition: NSString.cpp:278
bool NSTaggedString_SummaryProvider(ValueObject &valobj, ObjCLanguageRuntime::ClassDescriptorSP descriptor, Stream &stream, const TypeSummaryOptions &summary_options)
Definition: NSString.cpp:312
bool NSStringSummaryProvider(ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options)
Definition: NSString.cpp:33
A class that represents a running process on the host machine.
Definition: SBAddress.h:15
@ eBasicTypeUnsignedInt
std::shared_ptr< lldb_private::ValueObject > ValueObjectSP
Definition: lldb-forward.h:475
std::shared_ptr< lldb_private::Process > ProcessSP
Definition: lldb-forward.h:384
@ eByteOrderLittle
uint64_t addr_t
Definition: lldb-types.h:80
std::shared_ptr< lldb_private::Target > TargetSP
Definition: lldb-forward.h:439