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1//===- GsymCreator.h --------------------------------------------*- C++ -*-===//
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
12#include <functional>
13#include <memory>
14#include <mutex>
15#include <thread>
18#include "llvm/ADT/ArrayRef.h"
19#include "llvm/ADT/StringSet.h"
23#include "llvm/Support/Endian.h"
24#include "llvm/Support/Error.h"
25#include "llvm/Support/Path.h"
27namespace llvm {
29namespace gsym {
30class FileWriter;
31class OutputAggregator;
33/// GsymCreator is used to emit GSYM data to a stand alone file or section
34/// within a file.
36/// The GsymCreator is designed to be used in 3 stages:
37/// - Create FunctionInfo objects and add them
38/// - Finalize the GsymCreator object
39/// - Save to file or section
41/// The first stage involves creating FunctionInfo objects from another source
42/// of information like compiler debug info metadata, DWARF or Breakpad files.
43/// Any strings in the FunctionInfo or contained information, like InlineInfo
44/// or LineTable objects, should get the string table offsets by calling
45/// GsymCreator::insertString(...). Any file indexes that are needed should be
46/// obtained by calling GsymCreator::insertFile(...). All of the function calls
47/// in GsymCreator are thread safe. This allows multiple threads to create and
48/// add FunctionInfo objects while parsing debug information.
50/// Once all of the FunctionInfo objects have been added, the
51/// GsymCreator::finalize(...) must be called prior to saving. This function
52/// will sort the FunctionInfo objects, finalize the string table, and do any
53/// other passes on the information needed to prepare the information to be
54/// saved.
56/// Once the object has been finalized, it can be saved to a file or section.
60/// GSYM files are designed to be memory mapped into a process as shared, read
61/// only data, and used as is.
63/// The GSYM file format when in a stand alone file consists of:
64/// - Header
65/// - Address Table
66/// - Function Info Offsets
67/// - File Table
68/// - String Table
69/// - Function Info Data
71/// HEADER
73/// The header is fully described in "llvm/DebugInfo/GSYM/Header.h".
77/// The address table immediately follows the header in the file and consists
78/// of Header.NumAddresses address offsets. These offsets are sorted and can be
79/// binary searched for efficient lookups. Addresses in the address table are
80/// stored as offsets from a 64 bit base address found in Header.BaseAddress.
81/// This allows the address table to contain 8, 16, or 32 offsets. This allows
82/// the address table to not require full 64 bit addresses for each address.
83/// The resulting GSYM size is smaller and causes fewer pages to be touched
84/// during address lookups when the address table is smaller. The size of the
85/// address offsets in the address table is specified in the header in
86/// Header.AddrOffSize. The first offset in the address table is aligned to
87/// Header.AddrOffSize alignment to ensure efficient access when loaded into
88/// memory.
92/// The function info offsets table immediately follows the address table and
93/// consists of Header.NumAddresses 32 bit file offsets: one for each address
94/// in the address table. This data is aligned to a 4 byte boundary. The
95/// offsets in this table are the relative offsets from the start offset of the
96/// GSYM header and point to the function info data for each address in the
97/// address table. Keeping this data separate from the address table helps to
98/// reduce the number of pages that are touched when address lookups occur on a
99/// GSYM file.
103/// The file table immediately follows the function info offsets table. The
104/// encoding of the FileTable is:
106/// struct FileTable {
107/// uint32_t Count;
108/// FileEntry Files[];
109/// };
111/// The file table starts with a 32 bit count of the number of files that are
112/// used in all of the function info, followed by that number of FileEntry
113/// structures. The file table is aligned to a 4 byte boundary, Each file in
114/// the file table is represented with a FileEntry structure.
115/// See "llvm/DebugInfo/GSYM/FileEntry.h" for details.
119/// The string table follows the file table in stand alone GSYM files and
120/// contains all strings for everything contained in the GSYM file. Any string
121/// data should be added to the string table and any references to strings
122/// inside GSYM information must be stored as 32 bit string table offsets into
123/// this string table. The string table always starts with an empty string at
124/// offset zero and is followed by any strings needed by the GSYM information.
125/// The start of the string table is not aligned to any boundary.
129/// The function info data is the payload that contains information about the
130/// address that is being looked up. It contains all of the encoded
131/// FunctionInfo objects. Each encoded FunctionInfo's data is pointed to by an
132/// entry in the Function Info Offsets Table. For details on the exact encoding
133/// of FunctionInfo objects, see "llvm/DebugInfo/GSYM/FunctionInfo.h".
135 // Private member variables require Mutex protections
136 mutable std::mutex Mutex;
137 std::vector<FunctionInfo> Funcs;
138 StringTableBuilder StrTab;
139 StringSet<> StringStorage;
141 // Needed for mapping string offsets back to the string stored in \a StrTab.
143 std::vector<llvm::gsym::FileEntry> Files;
144 std::vector<uint8_t> UUID;
145 std::optional<AddressRanges> ValidTextRanges;
146 std::optional<uint64_t> BaseAddress;
147 bool IsSegment = false;
148 bool Finalized = false;
149 bool Quiet;
152 /// Get the first function start address.
153 ///
154 /// \returns The start address of the first FunctionInfo or std::nullopt if
155 /// there are no function infos.
156 std::optional<uint64_t> getFirstFunctionAddress() const;
158 /// Get the last function address.
159 ///
160 /// \returns The start address of the last FunctionInfo or std::nullopt if
161 /// there are no function infos.
162 std::optional<uint64_t> getLastFunctionAddress() const;
164 /// Get the base address to use for this GSYM file.
165 ///
166 /// \returns The base address to put into the header and to use when creating
167 /// the address offset table or std::nullpt if there are no valid
168 /// function infos or if the base address wasn't specified.
169 std::optional<uint64_t> getBaseAddress() const;
171 /// Get the size of an address offset in the address offset table.
172 ///
173 /// GSYM files store offsets from the base address in the address offset table
174 /// and we store the size of the address offsets in the GSYM header. This
175 /// function will calculate the size in bytes of these address offsets based
176 /// on the current contents of the GSYM file.
177 ///
178 /// \returns The size in byets of the address offsets.
179 uint8_t getAddressOffsetSize() const;
181 /// Get the maximum address offset for the current address offset size.
182 ///
183 /// This is used when creating the address offset table to ensure we have
184 /// values that are in range so we don't end up truncating address offsets
185 /// when creating GSYM files as the code evolves.
186 ///
187 /// \returns The maximum address offset value that will be encoded into a GSYM
188 /// file.
189 uint64_t getMaxAddressOffset() const;
191 /// Calculate the byte size of the GSYM header and tables sizes.
192 ///
193 /// This function will calculate the exact size in bytes of the encocded GSYM
194 /// for the following items:
195 /// - The GSYM header
196 /// - The Address offset table
197 /// - The Address info offset table
198 /// - The file table
199 /// - The string table
200 ///
201 /// This is used to help split GSYM files into segments.
202 ///
203 /// \returns Size in bytes the GSYM header and tables.
204 uint64_t calculateHeaderAndTableSize() const;
206 /// Copy a FunctionInfo from the \a SrcGC GSYM creator into this creator.
207 ///
208 /// Copy the function info and only the needed files and strings and add a
209 /// converted FunctionInfo into this object. This is used to segment GSYM
210 /// files into separate files while only transferring the files and strings
211 /// that are needed from \a SrcGC.
212 ///
213 /// \param SrcGC The source gsym creator to copy from.
214 /// \param FuncInfoIdx The function info index within \a SrcGC to copy.
215 /// \returns The number of bytes it will take to encode the function info in
216 /// this GsymCreator. This helps calculate the size of the current GSYM
217 /// segment file.
218 uint64_t copyFunctionInfo(const GsymCreator &SrcGC, size_t FuncInfoIdx);
220 /// Copy a string from \a SrcGC into this object.
221 ///
222 /// Copy a string from \a SrcGC by string table offset into this GSYM creator.
223 /// If a string has already been copied, the uniqued string table offset will
224 /// be returned, otherwise the string will be copied and a unique offset will
225 /// be returned.
226 ///
227 /// \param SrcGC The source gsym creator to copy from.
228 /// \param StrOff The string table offset from \a SrcGC to copy.
229 /// \returns The new string table offset of the string within this object.
230 uint32_t copyString(const GsymCreator &SrcGC, uint32_t StrOff);
232 /// Copy a file from \a SrcGC into this object.
233 ///
234 /// Copy a file from \a SrcGC by file index into this GSYM creator. Files
235 /// consist of two string table entries, one for the directory and one for the
236 /// filename, this function will copy any needed strings ensure the file is
237 /// uniqued within this object. If a file already exists in this GSYM creator
238 /// the uniqued index will be returned, else the stirngs will be copied and
239 /// the new file index will be returned.
240 ///
241 /// \param SrcGC The source gsym creator to copy from.
242 /// \param FileIdx The 1 based file table index within \a SrcGC to copy. A
243 /// file index of zero will always return zero as the zero is a reserved file
244 /// index that means no file.
245 /// \returns The new file index of the file within this object.
246 uint32_t copyFile(const GsymCreator &SrcGC, uint32_t FileIdx);
248 /// Inserts a FileEntry into the file table.
249 ///
250 /// This is used to insert a file entry in a thread safe way into this object.
251 ///
252 /// \param FE A file entry object that contains valid string table offsets
253 /// from this object already.
254 uint32_t insertFileEntry(FileEntry FE);
256 /// Fixup any string and file references by updating any file indexes and
257 /// strings offsets in the InlineInfo parameter.
258 ///
259 /// When copying InlineInfo entries, we can simply make a copy of the object
260 /// and then fixup the files and strings for efficiency.
261 ///
262 /// \param SrcGC The source gsym creator to copy from.
263 /// \param II The inline info that contains file indexes and string offsets
264 /// that come from \a SrcGC. The entries will be updated by coping any files
265 /// and strings over into this object.
266 void fixupInlineInfo(const GsymCreator &SrcGC, InlineInfo &II);
268 /// Save this GSYM file into segments that are roughly \a SegmentSize in size.
269 ///
270 /// When segemented GSYM files are saved to disk, they will use \a Path as a
271 /// prefix and then have the first function info address appended to the path
272 /// when each segment is saved. Each segmented GSYM file has a only the
273 /// strings and files that are needed to save the function infos that are in
274 /// each segment. These smaller files are easy to compress and download
275 /// separately and allow for efficient lookups with very large GSYM files and
276 /// segmenting them allows servers to download only the segments that are
277 /// needed.
278 ///
279 /// \param Path The path prefix to use when saving the GSYM files.
280 /// \param ByteOrder The endianness to use when saving the file.
281 /// \param SegmentSize The size in bytes to segment the GSYM file into.
282 llvm::Error saveSegments(StringRef Path, llvm::endianness ByteOrder,
283 uint64_t SegmentSize) const;
285 /// Let this creator know that this is a segment of another GsymCreator.
286 ///
287 /// When we have a segment, we know that function infos will be added in
288 /// ascending address range order without having to be finalized. We also
289 /// don't need to sort and unique entries during the finalize function call.
290 void setIsSegment() {
291 IsSegment = true;
292 }
295 GsymCreator(bool Quiet = false);
297 /// Save a GSYM file to a stand alone file.
298 ///
299 /// \param Path The file path to save the GSYM file to.
300 /// \param ByteOrder The endianness to use when saving the file.
301 /// \param SegmentSize The size in bytes to segment the GSYM file into. If
302 /// this option is set this function will create N segments
303 /// that are all around \a SegmentSize bytes in size. This
304 /// allows a very large GSYM file to be broken up into
305 /// shards. Each GSYM file will have its own file table,
306 /// and string table that only have the files and strings
307 /// needed for the shared. If this argument has no value,
308 /// a single GSYM file that contains all function
309 /// information will be created.
310 /// \returns An error object that indicates success or failure of the save.
312 std::optional<uint64_t> SegmentSize = std::nullopt) const;
314 /// Encode a GSYM into the file writer stream at the current position.
315 ///
316 /// \param O The stream to save the binary data to
317 /// \returns An error object that indicates success or failure of the save.
318 llvm::Error encode(FileWriter &O) const;
320 /// Insert a string into the GSYM string table.
321 ///
322 /// All strings used by GSYM files must be uniqued by adding them to this
323 /// string pool and using the returned offset for any string values.
324 ///
325 /// \param S The string to insert into the string table.
326 /// \param Copy If true, then make a backing copy of the string. If false,
327 /// the string is owned by another object that will stay around
328 /// long enough for the GsymCreator to save the GSYM file.
329 /// \returns The unique 32 bit offset into the string table.
330 uint32_t insertString(StringRef S, bool Copy = true);
332 /// Insert a file into this GSYM creator.
333 ///
334 /// Inserts a file by adding a FileEntry into the "Files" member variable if
335 /// the file has not already been added. The file path is split into
336 /// directory and filename which are both added to the string table. This
337 /// allows paths to be stored efficiently by reusing the directories that are
338 /// common between multiple files.
339 ///
340 /// \param Path The path to the file to insert.
341 /// \param Style The path style for the "Path" parameter.
342 /// \returns The unique file index for the inserted file.
346 /// Add a function info to this GSYM creator.
347 ///
348 /// All information in the FunctionInfo object must use the
349 /// GsymCreator::insertString(...) function when creating string table
350 /// offsets for names and other strings.
351 ///
352 /// \param FI The function info object to emplace into our functions list.
353 void addFunctionInfo(FunctionInfo &&FI);
355 /// Finalize the data in the GSYM creator prior to saving the data out.
356 ///
357 /// Finalize must be called after all FunctionInfo objects have been added
358 /// and before GsymCreator::save() is called.
359 ///
360 /// \param OS Output stream to report duplicate function infos, overlapping
361 /// function infos, and function infos that were merged or removed.
362 /// \returns An error object that indicates success or failure of the
363 /// finalize.
366 /// Set the UUID value.
367 ///
368 /// \param UUIDBytes The new UUID bytes.
370 UUID.assign(UUIDBytes.begin(), UUIDBytes.end());
371 }
373 /// Thread safe iteration over all function infos.
374 ///
375 /// \param Callback A callback function that will get called with each
376 /// FunctionInfo. If the callback returns false, stop iterating.
378 std::function<bool(FunctionInfo &)> const &Callback);
380 /// Thread safe const iteration over all function infos.
381 ///
382 /// \param Callback A callback function that will get called with each
383 /// FunctionInfo. If the callback returns false, stop iterating.
385 std::function<bool(const FunctionInfo &)> const &Callback) const;
387 /// Get the current number of FunctionInfo objects contained in this
388 /// object.
389 size_t getNumFunctionInfos() const;
391 /// Set valid .text address ranges that all functions must be contained in.
393 ValidTextRanges = TextRanges;
394 }
396 /// Get the valid text ranges.
397 const std::optional<AddressRanges> GetValidTextRanges() const {
398 return ValidTextRanges;
399 }
401 /// Check if an address is a valid code address.
402 ///
403 /// Any functions whose addresses do not exist within these function bounds
404 /// will not be converted into the final GSYM. This allows the object file
405 /// to figure out the valid file address ranges of all the code sections
406 /// and ensure we don't add invalid functions to the final output. Many
407 /// linkers have issues when dead stripping functions from DWARF debug info
408 /// where they set the DW_AT_low_pc to zero, but newer DWARF has the
409 /// DW_AT_high_pc as an offset from the DW_AT_low_pc and these size
410 /// attributes have no relocations that can be applied. This results in DWARF
411 /// where many functions have an DW_AT_low_pc of zero and a valid offset size
412 /// for DW_AT_high_pc. If we extract all valid ranges from an object file
413 /// that are marked with executable permissions, we can properly ensure that
414 /// these functions are removed.
415 ///
416 /// \param Addr An address to check.
417 ///
418 /// \returns True if the address is in the valid text ranges or if no valid
419 /// text ranges have been set, false otherwise.
420 bool IsValidTextAddress(uint64_t Addr) const;
422 /// Set the base address to use for the GSYM file.
423 ///
424 /// Setting the base address to use for the GSYM file. Object files typically
425 /// get loaded from a base address when the OS loads them into memory. Using
426 /// GSYM files for symbolication becomes easier if the base address in the
427 /// GSYM header is the same address as it allows addresses to be easily slid
428 /// and allows symbolication without needing to find the original base
429 /// address in the original object file.
430 ///
431 /// \param Addr The address to use as the base address of the GSYM file
432 /// when it is saved to disk.
434 BaseAddress = Addr;
435 }
437 /// Whether the transformation should be quiet, i.e. not output warnings.
438 bool isQuiet() const { return Quiet; }
441 /// Create a segmented GSYM creator starting with function info index
442 /// \a FuncIdx.
443 ///
444 /// This function will create a GsymCreator object that will encode into
445 /// roughly \a SegmentSize bytes and return it. It is used by the private
446 /// saveSegments(...) function and also is used by the GSYM unit tests to test
447 /// segmenting of GSYM files. The returned GsymCreator can be finalized and
448 /// encoded.
449 ///
450 /// \param [in] SegmentSize The size in bytes to roughly segment the GSYM file
451 /// into.
452 /// \param [in,out] FuncIdx The index of the first function info to encode
453 /// into the returned GsymCreator. This index will be updated so it can be
454 /// used in subsequent calls to this function to allow more segments to be
455 /// created.
456 /// \returns An expected unique pointer to a GsymCreator or an error. The
457 /// returned unique pointer can be NULL if there are no more functions to
458 /// encode.
460 createSegment(uint64_t SegmentSize, size_t &FuncIdx) const;
463} // namespace gsym
464} // namespace llvm
arc branch finalize
uint64_t Addr
raw_pwrite_stream & OS
StringSet - A set-like wrapper for the StringMap.
std::pair< llvm::MachO::Target, std::string > UUID
The AddressRanges class helps normalize address range collections.
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
iterator end() const
Definition: ArrayRef.h:154
iterator begin() const
Definition: ArrayRef.h:153
Lightweight error class with error context and mandatory checking.
Definition: Error.h:160
Tagged union holding either a T or a Error.
Definition: Error.h:474
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
StringSet - A wrapper for StringMap that provides set-like functionality.
Definition: StringSet.h:23
Utility for building string tables with deduplicated suffixes.
A simplified binary data writer class that doesn't require targets, target definitions,...
Definition: FileWriter.h:29
GsymCreator is used to emit GSYM data to a stand alone file or section within a file.
Definition: GsymCreator.h:134
void addFunctionInfo(FunctionInfo &&FI)
Add a function info to this GSYM creator.
uint32_t insertString(StringRef S, bool Copy=true)
Insert a string into the GSYM string table.
void setBaseAddress(uint64_t Addr)
Set the base address to use for the GSYM file.
Definition: GsymCreator.h:433
const std::optional< AddressRanges > GetValidTextRanges() const
Get the valid text ranges.
Definition: GsymCreator.h:397
llvm::Expected< std::unique_ptr< GsymCreator > > createSegment(uint64_t SegmentSize, size_t &FuncIdx) const
Create a segmented GSYM creator starting with function info index FuncIdx.
llvm::Error save(StringRef Path, llvm::endianness ByteOrder, std::optional< uint64_t > SegmentSize=std::nullopt) const
Save a GSYM file to a stand alone file.
Definition: GsymCreator.cpp:68
llvm::Error encode(FileWriter &O) const
Encode a GSYM into the file writer stream at the current position.
Definition: GsymCreator.cpp:80
bool isQuiet() const
Whether the transformation should be quiet, i.e. not output warnings.
Definition: GsymCreator.h:438
void setUUID(llvm::ArrayRef< uint8_t > UUIDBytes)
Set the UUID value.
Definition: GsymCreator.h:369
void SetValidTextRanges(AddressRanges &TextRanges)
Set valid .text address ranges that all functions must be contained in.
Definition: GsymCreator.h:392
uint32_t insertFile(StringRef Path, sys::path::Style Style=sys::path::Style::native)
Insert a file into this GSYM creator.
Definition: GsymCreator.cpp:29
size_t getNumFunctionInfos() const
Get the current number of FunctionInfo objects contained in this object.
bool IsValidTextAddress(uint64_t Addr) const
Check if an address is a valid code address.
void forEachFunctionInfo(std::function< bool(FunctionInfo &)> const &Callback)
Thread safe iteration over all function infos.
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
Definition: bit.h:70
Files in GSYM are contained in FileEntry structs where we split the directory and basename into two d...
Definition: FileEntry.h:24
Function information in GSYM files encodes information for one contiguous address range.
Definition: FunctionInfo.h:88
Inline information stores the name of the inline function along with an array of address ranges.
Definition: InlineInfo.h:59