Commit Graph

1575 Commits

Author SHA1 Message Date
Kazu Hirata 8afcfbfb8f Use true/false instead of 1/0 (NFC)
Identified by modernize-use-bool-literals.
2022-01-09 12:21:06 -08:00
Kazu Hirata b12fd13812 Fix bugprone argument comments.
Identified by bugprone-argument-comment.
2022-01-09 12:21:02 -08:00
Kazu Hirata b8336280d8 [lldb] Use nullptr instead of 0 or NULL (NFC)
This is a re-submission of 24d2405588
without the hunks in HostNativeThreadBase.{h,cpp}, which break builds
on Windows.

Identified with modernize-use-nullptr.
2022-01-01 11:54:25 -08:00
Kazu Hirata 95f7112be8 Revert "[lldb] Use nullptr instead of 0 or NULL (NFC)"
This reverts commit 913457acf0.

It again broke builds on Windows:

  lldb/source/Host/common/HostNativeThreadBase.cpp(37,14): error:
  assigning to 'lldb::thread_result_t' (aka 'unsigned int') from
  incompatible type 'std::nullptr_t'
2022-01-01 11:15:14 -08:00
Kazu Hirata 913457acf0 [lldb] Use nullptr instead of 0 or NULL (NFC)
This is a re-submission of 24d2405588
without the hunk in HostNativeThreadBase.h, which breaks builds on
Windows.

Identified with modernize-use-nullptr.
2022-01-01 10:48:56 -08:00
Nico Weber 4f2eeb6a65 Revert "[lldb] Use nullptr instead of 0 or NULL (NFC)"
This reverts commit 24d2405588.
Breaks building on Windows:

    ../../lldb/include\lldb/Host/HostNativeThreadBase.h(49,36): error:
        cannot initialize a member subobject of type 'lldb::thread_result_t'
        (aka 'unsigned int') with an rvalue of type 'std::nullptr_t'
      lldb::thread_result_t m_result = nullptr;
                                       ^~~~~~~
    1 error generated.
2022-01-01 13:35:54 -05:00
Kazu Hirata 24d2405588 [lldb] Use nullptr instead of 0 or NULL (NFC)
Identified with modernize-use-nullptr.
2022-01-01 08:54:05 -08:00
Greg Clayton a2154b1951 Cache the manual DWARF index out to the LLDB cache directory when the LLDB index cache is enabled.
This patch add the ability to cache the manual DWARF indexing results to disk for faster subsequent debug sessions. Manual DWARF indexing is time consuming and causes all DWARF to be fully parsed and indexed each time you debug a binary that doesn't have an acceptable accelerator table. Acceptable accelerator tables include .debug_names in DWARF5 or Apple accelerator tables.

This patch breaks up testing by testing all of the encoding and decoding of required C++ objects in a gtest unit test, and then has a test to verify the debug info cache is generated correctly.

This patch also adds the ability to track when a symbol table or DWARF index is loaded or saved to the cache in the "statistics dump" command. This is essential to know in statistics as it can help explain why a debug session was slower or faster than expected.

Reviewed By: labath, wallace

Differential Revision: https://reviews.llvm.org/D115951
2021-12-28 11:00:28 -08:00
Kazu Hirata 2d303e6781 Remove redundant return and continue statements (NFC)
Identified with readability-redundant-control-flow.
2021-12-24 23:17:54 -08:00
Greg Clayton da816ca0cb Added the ability to cache the finalized symbol tables subsequent debug sessions to start faster.
This is an updated version of the https://reviews.llvm.org/D113789 patch with the following changes:
- We no longer modify modification times of the cache files
- Use LLVM caching and cache pruning instead of making a new cache mechanism (See DataFileCache.h/.cpp)
- Add signature to start of each file since we are not using modification times so we can tell when caches are stale and remove and re-create the cache file as files are changed
- Add settings to control the cache size, disk percentage and expiration in days to keep cache size under control

This patch enables symbol tables to be cached in the LLDB index cache directory. All cache files are in a single directory and the files use unique names to ensure that files from the same path will re-use the same file as files get modified. This means as files change, their cache files will be deleted and updated. The modification time of each of the cache files is not modified so that access based pruning of the cache can be implemented.

The symbol table cache files start with a signature that uniquely identifies a file on disk and contains one or more of the following items:
- object file UUID if available
- object file mod time if available
- object name for BSD archive .o files that are in .a files if available

If none of these signature items are available, then the file will not be cached. This keeps temporary object files from expressions from being cached.

When the cache files are loaded on subsequent debug sessions, the signature is compare and if the file has been modified (uuid changes, mod time changes, or object file mod time changes) then the cache file is deleted and re-created.

Module caching must be enabled by the user before this can be used:

symbols.enable-lldb-index-cache (boolean) = false

(lldb) settings set symbols.enable-lldb-index-cache true

There is also a setting that allows the user to specify a module cache directory that defaults to a directory that defaults to being next to the symbols.clang-modules-cache-path directory in a temp directory:

(lldb) settings show symbols.lldb-index-cache-path
/var/folders/9p/472sr0c55l9b20x2zg36b91h0000gn/C/lldb/IndexCache

If this setting is enabled, the finalized symbol tables will be serialized and saved to disc so they can be quickly loaded next time you debug.

Each module can cache one or more files in the index cache directory. The cache file names must be unique to a file on disk and its architecture and object name for .o files in BSD archives. This allows universal mach-o files to support caching multuple architectures in the same module cache directory. Making the file based on the this info allows this cache file to be deleted and replaced when the file gets updated on disk. This keeps the cache from growing over time during the compile/edit/debug cycle and prevents out of space issues.

If the cache is enabled, the symbol table will be loaded from the cache the next time you debug if the module has not changed.

The cache also has settings to control the size of the cache on disk. Each time LLDB starts up with the index cache enable, the cache will be pruned to ensure it stays within the user defined settings:

(lldb) settings set symbols.lldb-index-cache-expiration-days <days>

A value of zero will disable cache files from expiring when the cache is pruned. The default value is 7 currently.

(lldb) settings set symbols.lldb-index-cache-max-byte-size <size>

A value of zero will disable pruning based on a total byte size. The default value is zero currently.
(lldb) settings set symbols.lldb-index-cache-max-percent <percentage-of-disk-space>

A value of 100 will allow the disc to be filled to the max, a value of zero will disable percentage pruning. The default value is zero.

Reviewed By: labath, wallace

Differential Revision: https://reviews.llvm.org/D115324
2021-12-16 09:59:55 -08:00
Luís Ferreira efefc4ee3b [lldb][NFC] Format lldb/include/lldb/Symbol/Type.h
Reviewed By: teemperor, JDevlieghere, dblaikie

Differential Revision: https://reviews.llvm.org/D113604
2021-12-14 19:31:18 +00:00
Lasse Folger b2e2eece9a [lldb][NFC] clang-format some files as preparation for https://reviews.llvm.org/D114627
Reviewed By: werat

Differential Revision: https://reviews.llvm.org/D115110
2021-12-09 12:38:00 +01:00
Dave Lee 13278efd0c [lldb] Remove some trivial scoped timers
While profiling lldb (from swift/llvm-project), these timers were noticed to be short lived and high firing, and so they add noise more than value.

The data points I recorded are:

`FindTypes_Impl`: 49,646 calls, 812ns avg, 40.33ms total
`AppendSymbolIndexesWithName`: 36,229 calls, 913ns avg, 33.09ms total
`FindAllSymbolsWithNameAndType`: 36,229 calls, 1.93µs avg, 70.05ms total
`FindSymbolsWithNameAndType`: 23,263 calls, 3.09µs avg, 71.88ms total

Differential Revision: https://reviews.llvm.org/D115182
2021-12-06 15:22:28 -08:00
Greg Clayton 7e6df41f65 [NFC] Refactor symbol table parsing.
Symbol table parsing has evolved over the years and many plug-ins contained duplicate code in the ObjectFile::GetSymtab() that used to be pure virtual. With this change, the "Symbtab *ObjectFile::GetSymtab()" is no longer virtual and will end up calling a new "void ObjectFile::ParseSymtab(Symtab &symtab)" pure virtual function to actually do the parsing. This helps centralize the code for parsing the symbol table and allows the ObjectFile base class to do all of the common work, like taking the necessary locks and creating the symbol table object itself. Plug-ins now just need to parse when they are asked to parse as the ParseSymtab function will only get called once.

This is a retry of the original patch https://reviews.llvm.org/D113965 which was reverted. There was a deadlock in the Manual DWARF indexing code during symbol preloading where the module was asked on the main thread to preload its symbols, and this would in turn cause the DWARF manual indexing to use a thread pool to index all of the compile units, and if there were relocations on the debug information sections, these threads could ask the ObjectFile to load section contents, which could cause a call to ObjectFileELF::RelocateSection() which would ask for the symbol table from the module and it would deadlock. We can't lock the module in ObjectFile::GetSymtab(), so the solution I am using is to use a llvm::once_flag to create the symbol table object once and then lock the Symtab object. Since all APIs on the symbol table use this lock, this will prevent anyone from using the symbol table before it is parsed and finalized and will avoid the deadlock I mentioned. ObjectFileELF::GetSymtab() was never locking the module lock before and would put off creating the symbol table until somewhere inside ObjectFileELF::GetSymtab(). Now we create it one time inside of the ObjectFile::GetSymtab() and immediately lock it which should be safe enough. This avoids the deadlocks and still provides safety.

Differential Revision: https://reviews.llvm.org/D114288
2021-11-30 13:54:32 -08:00
Luís Ferreira 2e5c47eda1
Revert "[lldb][NFC] Format lldb/include/lldb/Symbol/Type.h"
This reverts commit 6f99e1aa58.
2021-11-30 00:52:53 +00:00
Luís Ferreira 6f99e1aa58
[lldb][NFC] Format lldb/include/lldb/Symbol/Type.h
Reviewed By: teemperor, JDevlieghere

Differential Revision: https://reviews.llvm.org/D113604

Signed-off-by: Luís Ferreira <contact@lsferreira.net>
2021-11-29 23:55:58 +00:00
Greg Clayton a68ccda203 Revert "[NFC] Refactor symbol table parsing."
This reverts commit 951b107eed.

Buildbots were failing, there is a deadlock in /Users/gclayton/Documents/src/llvm/clean/llvm-project/lldb/test/Shell/SymbolFile/DWARF/DW_AT_range-DW_FORM_sec_offset.s when ELF files try to relocate things.
2021-11-17 18:07:28 -08:00
Greg Clayton 951b107eed [NFC] Refactor symbol table parsing.
Symbol table parsing has evolved over the years and many plug-ins contained duplicate code in the ObjectFile::GetSymtab() that used to be pure virtual. With this change, the "Symbtab *ObjectFile::GetSymtab()" is no longer virtual and will end up calling a new "void ObjectFile::ParseSymtab(Symtab &symtab)" pure virtual function to actually do the parsing. This helps centralize the code for parsing the symbol table and allows the ObjectFile base class to do all of the common work, like taking the necessary locks and creating the symbol table object itself. Plug-ins now just need to parse when they are asked to parse as the ParseSymtab function will only get called once.

Differential Revision: https://reviews.llvm.org/D113965
2021-11-17 15:14:01 -08:00
Luís Ferreira 96a7359908 [lldb] Add support for demangling D symbols
This is part of https://github.com/dlang/projects/issues/81 .

This patch enables support for D programming language demangler by using a
pretty printed stacktrace with demangled D symbols, when present.

Signed-off-by: Luís Ferreira <contact@lsferreira.net>

Reviewed By: JDevlieghere, teemperor

Differential Revision: https://reviews.llvm.org/D110578
2021-11-11 11:11:21 +01:00
Zequan Wu cc9ced0ed4 [LLDB][Breakpad] Make lldb understand INLINE and INLINE_ORIGIN records in breakpad.
Teach LLDB to understand INLINE and INLINE_ORIGIN records in breakpad.
They have the following formats:
```
INLINE inline_nest_level call_site_line call_site_file_num origin_num [address size]+
INLINE_ORIGIN origin_num name
```
`INLNIE_ORIGIN` is simply a string pool for INLINE so that we won't have
duplicated names for inlined functions and can show up anywhere in the symbol
file.
`INLINE` follows immediately after `FUNC` represents the ranges of momery
address that has functions inlined inside the function.

Differential Revision: https://reviews.llvm.org/D113330
2021-11-10 11:20:32 -08:00
Adrian Prantl c9881c7d99 Support looking up absolute symbols
The Swift stdlib uses absolute symbols in the dylib to communicate
feature flags to the process. LLDB's expression evaluator needs to be
able to find them. This wires up absolute symbols so they show up in
the symtab lookup command, which is also all that's needed for them to
be visible to the expression evaluator JIT.

rdar://85093828

Differential Revision: https://reviews.llvm.org/D113445
2021-11-09 09:44:37 -08:00
Benjamin Kramer 48677f58b0 [lldb] Unbreak the macOS build after dfd499a61c 2021-11-02 09:47:44 +01:00
Greg Clayton 2887d9fd86 Add new key/value pairs to the module statistics for "statistics dump".
The new key/value pairs that are added to each module's stats are:
"debugInfoByteSize": The size in bytes of debug info for each module.
"debugInfoIndexTime": The time in seconds that it took to index the debug info.
"debugInfoParseTime": The time in seconds that debug info had to be parsed.

At the top level we add up all of the debug info size, parse time and index time with the following keys:
"totalDebugInfoByteSize": The size in bytes of all debug info in all modules.
"totalDebugInfoIndexTime": The time in seconds that it took to index all debug info if it was indexed for all modules.
"totalDebugInfoParseTime": The time in seconds that debug info was parsed for all modules.

Differential Revision: https://reviews.llvm.org/D112501
2021-10-26 15:09:31 -07:00
Greg Clayton c571988e9d Add modules stats into the "statistics dump" command.
The new module stats adds the ability to measure the time it takes to parse and index the symbol tables for each module, and reports modules statistics in the output of "statistics dump" along with the path, UUID and triple of the module. The time it takes to parse and index the symbol tables are also aggregated into new top level key/value pairs at the target level.

Differential Revision: https://reviews.llvm.org/D112279
2021-10-25 11:50:02 -07:00
Pavel Labath a3939e159f [lldb] Return StringRef from PluginInterface::GetPluginName
There is no reason why this function should be returning a ConstString.

While modifying these files, I also fixed several instances where
GetPluginName and GetPluginNameStatic were returning different strings.

I am not changing the return type of GetPluginNameStatic in this patch, as that
would necessitate additional changes, and this patch is big enough as it is.

Differential Revision: https://reviews.llvm.org/D111877
2021-10-18 10:14:42 +02:00
Michał Górny 3a6ba36751 [lldb] Convert misc. StringConvert uses
Replace misc. StringConvert uses with llvm::to_integer()
and llvm::to_float(), except for cases where further refactoring is
planned.  The purpose of this change is to eliminate the StringConvert
API that is duplicate to LLVM, and less correct in behavior at the same
time.

Differential Revision: https://reviews.llvm.org/D110447
2021-09-25 14:19:19 +02:00
Alex Langford c4a406bbd0 [lldb][NFC] Remove outdated FIXME 2021-09-20 11:44:20 -07:00
Pavel Labath b03126768a [lldb] Remove PluginInterface::GetPluginVersion
In all these years, we haven't found a use for this function (it has
zero callers). Lets just remove the boilerplate.

Differential Revision: https://reviews.llvm.org/D109600
2021-09-13 10:29:00 +02:00
Nico Weber cfe0284749 [gn build] Add build files for LLDB
This is enough to get the lit-based tests to pass on macOS.

Doesn't yet add build targets for:
- Any LLDB unit tests
- swig bindings
- various targets not needed by lit tests

LLDB has many dependency cycles, something GN doesn't allow. For
that reason, I've omitted some dependency edges. Hopefully we can
clean up the cycles one day.

LLDB has a public/private header distinction, but mostly ignores it.
Many libraries include private headers from other modules.

Since LLDB is the first target the LLVM/GN build that uses Objective-C++
code, add some machinery to the toolchain file to handle that.

Differential Revision: https://reviews.llvm.org/D109185
2021-09-07 15:25:04 -04:00
Kim-Anh Tran 3973d8b29e [lldb] Return all line entries matchign a line if no column is specified
Previously, if no column was specified, ResolveSymbolContext would take
the first match returned by FindLineEntryIndexByFileIndex, and reuse it
to find subsequent exact matches. With the introduction of columns, columns
are now considered when matching the line entries.

This leads to a problem if one wants to get all existing line entries
that match that line, since now the column is also used for the exact match.
This way, all line entries are filtered out that have a different
column number, but the same line number.

This patch changes that by ignoring the column information of the first match
if the original request of ResolveSymbolContext was also ignoring it.

Reviewed By: mib

Differential Revision: https://reviews.llvm.org/D108816
2021-08-30 14:45:46 +02:00
Alex Langford 4947f6d8bc [lldb][NFC] Remove unused header include 2021-08-19 11:06:56 -07:00
Dimitry Andric 5033f0793f [lldb] Avoid unhandled Error in TypeSystemMap::GetTypeSystemForLanguage
When assertions are turned off, the `llvm::Error` value created at the
start of this function is overwritten using the move-assignment
operator, but the success value is never checked. Whenever a TypeSystem
cannot be found or created, this can lead to lldb core dumping with:

    Program aborted due to an unhandled Error:
    Error value was Success. (Note: Success values must still be checked prior to being destroyed).

Fix this by not creating a `llvm::Error` value in advance, and directly
returning the result of `llvm::make_error` instead, whenever an error is
encountered.

See also: <https://bugs.freebsd.org/253881> and
<https://bugs.freebsd.org/257829>.

Reviewed By: teemperor

Differential Revision: https://reviews.llvm.org/D108088
2021-08-16 17:34:42 +02:00
Eric Leese 437e37dd55 [nfc] [lldb] Support moving support files instead of copy
Split from D100299.

Reviewed By: jankratochvil

Differential Revision: https://reviews.llvm.org/D107165
2021-08-02 21:43:34 +02:00
Eric Leese fb09f365ae [lldb] [DWARF-5] Be lazier about loading .dwo files
This change makes sure that DwarfUnit does not load a .dwo file until
necessary. I also take advantage of DWARF 5's guarantee that the first
support file is also the primary file to make it possible to create
a compile unit without loading the .dwo file.

Testcases now require Linux as it is needed for -gsplit-dwarf.

Review By: jankratochvil, dblaikie

Differential Revision: https://reviews.llvm.org/D100299
2021-07-31 10:45:31 +02:00
Stella Stamenova dfb6f7b015 Revert "[lldb] [DWARF-5] Be lazier about loading .dwo files"
This reverts commit 8dfd6cae9b.

This change broke the windows lldb bot:
https://lab.llvm.org/buildbot/#/builders/83/builds/8842
2021-07-30 18:33:13 -07:00
Eric Leese 8dfd6cae9b [lldb] [DWARF-5] Be lazier about loading .dwo files
This change makes sure that DwarfUnit does not load a .dwo file until
necessary. I also take advantage of DWARF 5's guarantee that the first
support file is also the primary file to make it possible to create
a compile unit without loading the .dwo file.

Review By: jankratochvil, dblaikie

Differential Revision: https://reviews.llvm.org/D100299
2021-07-30 23:17:06 +02:00
Jan Kratochvil d0e6d946b6 Revert "[lldb] [DWARF-5] Be lazier about loading .dwo files"
This reverts commit e7b8ba103a.

It broke 32-bit ARM - lldb-arm-ubuntu, reported by omjavaid:
  https://lab.llvm.org/buildbot/#/builders/17/builds/9595
2021-07-30 14:54:27 +02:00
Eric Leese e7b8ba103a [lldb] [DWARF-5] Be lazier about loading .dwo files
This change makes sure that DwarfUnit does not load a .dwo file until
necessary. I also take advantage of DWARF 5's guarantee that the first
support file is also the primary file to make it possible to create
a compile unit without loading the .dwo file.

Review By: jankratochvil, dblaikie

Differential Revision: https://reviews.llvm.org/D100299
2021-07-30 13:34:51 +02:00
Greg Clayton ec1a491701 Create synthetic symbol names on demand to improve memory consumption and startup times.
This is a resubmission of https://reviews.llvm.org/D105160 after fixing testing issues.

This fix was created after profiling the target creation of a large C/C++/ObjC application that contained almost 4,000,000 redacted symbol names. The symbol table parsing code was creating names for each of these synthetic symbols and adding them to the name indexes. The code was also adding the object file basename to the end of the symbol name which doesn't allow symbols from different shared libraries to share the names in the constant string pool.

Prior to this fix this was creating 180MB of "___lldb_unnamed_symbol" symbol names and was taking a long time to generate each name, add them to the string pool and then add each of these names to the name index.

This patch fixes the issue by:

not adding a name to synthetic symbols at creation time, and allows name to be dynamically generated when accessed
doesn't add synthetic symbol names to the name indexes, but catches this special case as name lookup time. Users won't typically set breakpoints or lookup these synthetic names, but support was added to do the lookup in case it does happen
removes the object file baseanme from the generated names to allow the names to be shared in the constant string pool
Prior to this fix the startup times for a large application was:
12.5 seconds (cold file caches)
8.5 seconds (warm file caches)

After this fix:
9.7 seconds (cold file caches)
5.7 seconds (warm file caches)

The names of the symbols are auto generated by appending the symbol's UserID to the end of the "___lldb_unnamed_symbol" string and is only done when the name is requested from a synthetic symbol if it has no name.

Differential Revision: https://reviews.llvm.org/D106837
2021-07-27 16:51:12 -07:00
Jonas Devlieghere 6b0d266036 Revert "Create synthetic symbol names on demand to improve memory consumption and startup times."
This reverts commit c8164d0276 and
43f6dad234 because it breaks
TestDyldTrieSymbols.py on GreenDragon.
2021-07-02 16:21:47 -07:00
Jonas Devlieghere fd2433e139 [lldb] Replace default bodies of special member functions with = default;
Replace default bodies of special member functions with = default;

$ run-clang-tidy.py -header-filter='lldb' -checks='-*,modernize-use-equals-default' -fix ,

https://clang.llvm.org/extra/clang-tidy/checks/modernize-use-equals-default.html

Differential revision: https://reviews.llvm.org/D104041
2021-07-02 11:31:16 -07:00
Greg Clayton 43f6dad234 Fix buildbot compile error for https://reviews.llvm.org/D105160. 2021-06-29 18:03:25 -07:00
Greg Clayton c8164d0276 Create synthetic symbol names on demand to improve memory consumption and startup times.
This fix was created after profiling the target creation of a large C/C++/ObjC application that contained almost 4,000,000 redacted symbol names. The symbol table parsing code was creating names for each of these synthetic symbols and adding them to the name indexes. The code was also adding the object file basename to the end of the symbol name which doesn't allow symbols from different shared libraries to share the names in the constant string pool.

Prior to this fix this was creating 180MB of "___lldb_unnamed_symbol" symbol names and was taking a long time to generate each name, add them to the string pool and then add each of these names to the name index.

This patch fixes the issue by:
- not adding a name to synthetic symbols at creation time, and allows name to be dynamically generated when accessed
- doesn't add synthetic symbol names to the name indexes, but catches this special case as name lookup time. Users won't typically set breakpoints or lookup these synthetic names, but support was added to do the lookup in case it does happen
- removes the object file baseanme from the generated names to allow the names to be shared in the constant string pool

Prior to this fix the startup times for a large application was:
12.5 seconds (cold file caches)
8.5 seconds (warm file caches)

After this fix:
9.7 seconds (cold file caches)
5.7 seconds (warm file caches)

The names of the symbols are auto generated by appending the symbol's UserID to the end of the "___lldb_unnamed_symbol" string and is only done when the name is requested from a synthetic symbol if it has no name.

Differential Revision: https://reviews.llvm.org/D105160
2021-06-29 17:44:33 -07:00
Adrian Prantl a346372200 Change PathMappingList::FindFile to return an optional result (NFC)
This is an NFC modernization refactoring that replaces the combination
of a bool return + reference argument, with an Optional return value.

Differential Revision: https://reviews.llvm.org/D104405
2021-06-29 15:10:46 -07:00
Stella Stamenova bb2cfca2f3 Revert D104488 and friends since it broke the windows bot
Reverts commits:
"Fix failing tests after https://reviews.llvm.org/D104488."
"Fix buildbot failure after https://reviews.llvm.org/D104488."
"Create synthetic symbol names on demand to improve memory consumption and startup times."

This series of commits broke the windows lldb bot and then failed to fix all of the failing tests.
2021-06-29 12:58:55 -07:00
Greg Clayton 323bcbdba0 Fix buildbot failure after https://reviews.llvm.org/D104488. 2021-06-28 18:12:05 -07:00
Greg Clayton d77ccfdc72 Create synthetic symbol names on demand to improve memory consumption and startup times.
This fix was created after profiling the target creation of a large C/C++/ObjC application that contained almost 4,000,000 redacted symbol names. The symbol table parsing code was creating names for each of these synthetic symbols and adding them to the name indexes. The code was also adding the object file basename to the end of the symbol name which doesn't allow symbols from different shared libraries to share the names in the constant string pool.

Prior to this fix this was creating 180MB of "___lldb_unnamed_symbol" symbol names and was taking a long time to generate each name, add them to the string pool and then add each of these names to the name index.

This patch fixes the issue by:
- not adding a name to synthetic symbols at creation time, and allows name to be dynamically generated when accessed
- doesn't add synthetic symbol names to the name indexes, but catches this special case as name lookup time. Users won't typically set breakpoints or lookup these synthetic names, but support was added to do the lookup in case it does happen
- removes the object file baseanme from the generated names to allow the names to be shared in the constant string pool

Prior to this fix the startup times for a large application was:
12.5 seconds (cold file caches)
8.5 seconds (warm file caches)

After this fix:
9.7 seconds (cold file caches)
5.7 seconds (warm file caches)

The names of the symbols are auto generated by appending the symbol's UserID to the end of the "___lldb_unnamed_symbol" string and is only done when the name is requested from a synthetic symbol if it has no name.

Differential Revision: https://reviews.llvm.org/D104488
2021-06-28 18:04:51 -07:00
Alex Langford 5bebc0b177 [lldb] Decouple ObjCLanguage from Symtab
We can extend/modify `GetMethodNameVariants` to suit our purposes here.
What symtab is looking for is alternate names we may want to use to
search for a specific symbol, and asking for variants of a name makes
the most sense here.

Differential Revision: https://reviews.llvm.org/D104067
2021-06-23 13:49:46 -07:00
Alexander Mols 0a2d4f3f24 [lldb] Enable Rust v0 symbol demangling
Rust's v0 name mangling scheme [1] is easy to disambiguate from other
name mangling schemes because symbols always start with `_R`. The llvm
Demangle library supports demangling the Rust v0 scheme. Use it to
demangle Rust symbols.

Added unit tests that check simple symbols. Ran LLDB built with this
patch to debug some Rust programs compiled with the v0 name mangling
scheme. Confirmed symbol names were demangled as expected.

Note: enabling the new name mangling scheme requires a nightly
toolchain:

```
$ cat main.rs
fn main() {
    println!("Hello world!");
}
$ $(rustup which --toolchain nightly rustc) -Z symbol-mangling-version=v0 main.rs -g
$ /home/asm/hacking/llvm/build/bin/lldb ./main --one-line 'b main.rs:2'
(lldb) target create "./main"
Current executable set to '/home/asm/hacking/llvm/rust/main' (x86_64).
(lldb) b main.rs:2
Breakpoint 1: where = main`main::main + 4 at main.rs:2:5, address = 0x00000000000076a4
(lldb) r
Process 948449 launched: '/home/asm/hacking/llvm/rust/main' (x86_64)
warning: (x86_64) /lib64/libgcc_s.so.1 No LZMA support found for reading .gnu_debugdata section
Process 948449 stopped
* thread #1, name = 'main', stop reason = breakpoint 1.1
    frame #0: 0x000055555555b6a4 main`main::main at main.rs:2:5
   1    fn main() {
-> 2        println!("Hello world!");
   3    }
(lldb) bt
error: need to add support for DW_TAG_base_type '()' encoded with DW_ATE = 0x7, bit_size = 0
* thread #1, name = 'main', stop reason = breakpoint 1.1
  * frame #0: 0x000055555555b6a4 main`main::main at main.rs:2:5
    frame #1: 0x000055555555b78b main`<fn() as core::ops::function::FnOnce<()>>::call_once((null)=(main`main::main at main.rs:1), (null)=<unavailable>) at function.rs:227:5
    frame #2: 0x000055555555b66e main`std::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>(f=(main`main::main at main.rs:1)) at backtrace.rs:125:18
    frame #3: 0x000055555555b851 main`std::rt::lang_start::<()>::{closure#0} at rt.rs:49:18
    frame #4: 0x000055555556c9f9 main`std::rt::lang_start_internal::hc51399759a90501a [inlined] core::ops::function::impls::_$LT$impl$u20$core..ops..function..FnOnce$LT$A$GT$$u20$for$u20$$RF$F$GT$::call_once::h04259e4a34d07c2f at function.rs:259:13
    frame #5: 0x000055555556c9f2 main`std::rt::lang_start_internal::hc51399759a90501a [inlined] std::panicking::try::do_call::hb8da45704d5cfbbf at panicking.rs:401:40
    frame #6: 0x000055555556c9f2 main`std::rt::lang_start_internal::hc51399759a90501a [inlined] std::panicking::try::h4beadc19a78fec52 at panicking.rs:365:19
    frame #7: 0x000055555556c9f2 main`std::rt::lang_start_internal::hc51399759a90501a [inlined] std::panic::catch_unwind::hc58016cd36ba81a4 at panic.rs:433:14
    frame #8: 0x000055555556c9f2 main`std::rt::lang_start_internal::hc51399759a90501a at rt.rs:34:21
    frame #9: 0x000055555555b830 main`std::rt::lang_start::<()>(main=(main`main::main at main.rs:1), argc=1, argv=0x00007fffffffcb18) at rt.rs:48:5
    frame #10: 0x000055555555b6fc main`main + 28
    frame #11: 0x00007ffff73f2493 libc.so.6`__libc_start_main + 243
    frame #12: 0x000055555555b59e main`_start + 46
(lldb)
```

[1]: https://github.com/rust-lang/rust/issues/60705

Reviewed By: clayborg, teemperor

Differential Revision: https://reviews.llvm.org/D104054
2021-06-21 18:20:15 +02:00
Jonas Devlieghere 9494c510af [lldb] Use C++11 default member initializers
This converts a default constructor's member initializers into C++11
default member initializers. This patch was automatically generated with
clang-tidy and the modernize-use-default-member-init check.

$ run-clang-tidy.py -header-filter='lldb' -checks='-*,modernize-use-default-member-init' -fix

This is a mass-refactoring patch and this commit will be added to
.git-blame-ignore-revs.

Differential revision: https://reviews.llvm.org/D103483
2021-06-09 09:43:13 -07:00