Commit Graph

310 Commits

Author SHA1 Message Date
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
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
2ace1e5753 [lldb] Remove ConstString from GetPluginNameStatic of some plugins
This patch deals with ObjectFile, ObjectContainer and OperatingSystem
plugins. I'll convert the other types in separate patches.

In order to enable piecemeal conversion, I am leaving some ConstStrings
in the lowest PluginManager layers. I'll convert those as the last step.

Differential Revision: https://reviews.llvm.org/D112061
2021-10-21 12:58:45 +02:00
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
Pavel Labath
93c1b3caf0 [lldb] Remove some anonymous namespaces
.. and reduce the scope of others. They don't follow llvm coding
standards (which say they should be used only when the same effect
cannot be achieved with the static keyword), and they set a bad example.
2021-10-05 08:35:18 +02:00
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
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
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
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
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
Pavel Labath
e5984a3680 [lldb/elf] Avoid side effects in function calls ParseUnwindSymbols
This addresses post-commit feedback to cd64273.
2021-04-22 14:31:00 +02:00
Pavel Labath
cd64273f5e [lldb/ELF] Fix IDs of synthetic eh_frame symbols
The code used the total number of symbols to create a symbol ID for the
synthetic symbols. This is not correct because the IDs of real symbols
can be higher than their total number, as we do not add all symbols (and
in particular, we never add symbol zero, which is not a real symbol).

This meant we could have symbols with duplicate IDs, which caused
problems if some relocations were referring to the duplicated IDs. This
was the cause of the failure of the test D97786.

This patch fixes the code to use the ID of the highest (last) symbol
instead.
2021-04-21 11:24:43 +02:00
Jason Molenda
e9fe788d32 Target::ReadMemory read from read-only binary file Section, not memory
Commiting this patch for Augusto Noronha who is getting set
up still.

This patch changes Target::ReadMemory so the default behavior
when a read is in a Section that is read-only is to fetch the
data from the local binary image, instead of reading it from
memory.  Update all callers to use their old preferences
(the old prefer_file_cache bool) using the new API; we should
revisit these calls and see if they really intend to read
live memory, or if reading from a read-only Section would be
equivalent and important for performance-sensitive cases.

rdar://30634422

Differential revision: https://reviews.llvm.org/D100338
2021-04-16 16:13:07 -07:00
Greg Clayton
e122877f10 Add a progress class that can track long running operations in LLDB.
LLDB can often appear deadlocked to users that use IDEs when it is indexing DWARF, or parsing symbol tables. These long running operations can make a debug session appear to be doing nothing even though a lot of work is going on inside LLDB. This patch adds a public API to allow clients to listen to debugger events that report progress and will allow UI to create an activity window or display that can show users what is going on and keep them informed of expensive operations that are going on inside LLDB.

Differential Revision: https://reviews.llvm.org/D97739
2021-03-24 12:58:13 -07:00
Peter Collingbourne
c314f5ede8 ObjectFileELF: Test whether reloc_header is non-null instead of asserting.
It is possible for the GetSectionHeaderByIndex lookup to fail because
the previous FindSectionContainingFileAddress lookup found a segment
instead of a section. This is possible if the binary does not have
a PLT (which means that lld will in some circumstances set DT_JMPREL
to 0, which is typically an address that is part of the ELF headers
and not in a section) and may also be possible if the section headers
have been stripped. To handle this possibility, replace the assert
with an if.

Differential Revision: https://reviews.llvm.org/D93438
2021-02-11 15:05:18 -08:00
Luís Marques
15f5971150 [LLDB][RISCV] Add RISC-V ArchSpec and rv32/rv64 variant detection
Adds the RISC-V ArchSpec bits contributed by @simoncook as part of D62732,
plus logic to distinguish between riscv32 and riscv64 based on ELF class.

The patch follows the implementation approach previously used for MIPS.
It defines RISC-V architecture subtypes and inspects the ELF header,
namely the ELF class, to detect the right subtype.

Differential Revision: https://reviews.llvm.org/D86292
2021-01-07 23:02:55 +00:00
Jonas Devlieghere
5c1c8443eb [lldb] Abstract scoped timer logic behind LLDB_SCOPED_TIMER (NFC)
This patch introduces a LLDB_SCOPED_TIMER macro to hide the needlessly
repetitive creation of scoped timers in LLDB. It's similar to the
LLDB_LOG(F) macro.

Differential revision: https://reviews.llvm.org/D93663
2020-12-22 09:10:27 -08:00
Fred Riss
a4a00ced0c [lldb/Module] Allow for the creation of memory-only modules
Summary:
This patch extends the ModuleSpec class to include a
DataBufferSP which contains the module data. If this
data is provided, LLDB won't try to hit the filesystem
to create the Module, but use only the data stored in
the ModuleSpec.

Reviewers: labath, espindola

Subscribers: emaste, MaskRay, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D83512
2020-07-14 08:45:44 -07:00
Jonas Devlieghere
06412dae82 [lldb] Use std::make_unique<> (NFC)
Update the rest of lldb to use std::make_unique<>. I used clang-tidy to
automate this, which probably missed cases that are wrapped in ifdefs.
2020-06-24 17:48:40 -07:00
Pavel Labath
3a16829748 [lldb] Switch Section-dumping code to raw_ostream
Also, add a basic test for dumping sections.
2020-05-14 11:59:18 +02:00
Kazuaki Ishizaki
e9264b746b [lldb] NFC: Fix trivial typo in comments, documents, and messages
Differential Revision: https://reviews.llvm.org/D77460
2020-04-07 01:06:16 +09:00
Kai Wang
581ba35291 [RISCV] ELF attribute section for RISC-V.
Leverage ARM ELF build attribute section to create ELF attribute section
for RISC-V. Extract the common part of parsing logic for this section
into ELFAttributeParser.[cpp|h] and ELFAttributes.[cpp|h].

Differential Revision: https://reviews.llvm.org/D74023
2020-03-31 16:16:19 +08:00
Pavel Labath
7b59ff2fa0 [lldb] Add boilerplate to recognize the .debug_tu_index section
It's just like debug_cu_index, only for type units.
2020-02-20 13:44:21 +01:00
Jonas Devlieghere
bba9ba8d95 [lldb/Plugin] s/LLDB_PLUGIN/LLDB_PLUGIN_DEFINE/ (NFC)
Rename LLDB_PLUGIN to LLDB_PLUGIN_DEFINE as Pavel suggested in D73067 to
avoid name conflict.
2020-02-14 09:58:24 -08:00
Martin Storsjö
6115bd9ba2 [LLDB] Fix GCC warnings about extra semicolons. NFC. 2020-02-10 11:20:44 +02:00
Jonas Devlieghere
fbb4d1e43d [lldb/Plugins] Use external functions to (de)initialize plugins
This is a step towards making the initialize and terminate calls be
generated by CMake, which in turn is towards making it possible to
disable plugins at configuration time.

Differential revision: https://reviews.llvm.org/D74245
2020-02-07 15:28:27 -08:00
Michał Górny
98594a44aa [lldb] [ObjectFile/ELF] Fix negated seg ids on 32-bit arches
Scale segment identifier up to user_id_t before negating it.  This fixes
the identifers being wrongly e.g. 0x00000000fffffffe instead of
0xfffffffffffffffe.  Fix suggested by Pavel Labath.

This fixes 5 tests failing on i386 (PR #44748):

  lldb-shell :: ObjectFile/ELF/PT_LOAD-overlap-PT_INTERP.yaml
  lldb-shell :: ObjectFile/ELF/PT_LOAD-overlap-PT_TLS.yaml
  lldb-shell :: ObjectFile/ELF/PT_LOAD-overlap-section.yaml
  lldb-shell :: ObjectFile/ELF/PT_LOAD.yaml
  lldb-shell :: ObjectFile/ELF/PT_TLS-overlap-PT_LOAD.yaml

Differential Revision: https://reviews.llvm.org/D73914
2020-02-04 05:50:56 +01:00
Alex Langford
22b044877d [lldb][NFCI] Remove unused LanguageType parameters
These parameters are unused in these methods, and some of them only had a
LanguageType parameter to pipe to other methods that don't use it
either.
2020-01-30 21:57:23 -08:00
Benjamin Kramer
adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
Raphael Isemann
808142876c [lldb][NFC] Fix all formatting errors in .cpp file headers
Summary:
A *.cpp file header in LLDB (and in LLDB) should like this:
```
//===-- TestUtilities.cpp -------------------------------------------------===//
```
However in LLDB most of our source files have arbitrary changes to this format and
these changes are spreading through LLDB as folks usually just use the existing
source files as templates for their new files (most notably the unnecessary
editor language indicator `-*- C++ -*-` is spreading and in every review
someone is pointing out that this is wrong, resulting in people pointing out that this
is done in the same way in other files).

This patch removes most of these inconsistencies including the editor language indicators,
all the different missing/additional '-' characters, files that center the file name, missing
trailing `===//` (mostly caused by clang-format breaking the line).

Reviewers: aprantl, espindola, jfb, shafik, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: dexonsmith, wuzish, emaste, sdardis, nemanjai, kbarton, MaskRay, atanasyan, arphaman, jfb, abidh, jsji, JDevlieghere, usaxena95, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D73258
2020-01-24 08:52:55 +01:00
Pavel Labath
4b5bc38802 [lldb/DWARF] Move location list sections into DWARFContext
These are the last sections not managed by the DWARFContext object. I
also introduce separate SectionType enums for dwo section variants, as
this is necessary for proper handling of single-file split dwarf.
2020-01-14 15:19:29 +01:00
Jan Kratochvil
bf7225888a [lldb] Fix lookup of symbols with the same address range but different binding
This fixes a failing testcase on Fedora 30 x86_64 (regression Fedora 29->30):

PASS:
./bin/lldb ./lldb-test-build.noindex/functionalities/unwind/noreturn/TestNoreturnUnwind.test_dwarf/a.out -o 'settings set symbols.enable-external-lookup false' -o r -o bt -o quit
  * frame #0: 0x00007ffff7aa6e75 libc.so.6`__GI_raise + 325
    frame #1: 0x00007ffff7a91895 libc.so.6`__GI_abort + 295
    frame #2: 0x0000000000401140 a.out`func_c at main.c:12:2
    frame #3: 0x000000000040113a a.out`func_b at main.c:18:2
    frame #4: 0x0000000000401134 a.out`func_a at main.c:26:2
    frame #5: 0x000000000040112e a.out`main(argc=<unavailable>, argv=<unavailable>) at main.c:32:2
    frame #6: 0x00007ffff7a92f33 libc.so.6`__libc_start_main + 243
    frame #7: 0x000000000040106e a.out`_start + 46

vs.

FAIL - unrecognized abort() function:
./bin/lldb ./lldb-test-build.noindex/functionalities/unwind/noreturn/TestNoreturnUnwind.test_dwarf/a.out -o 'settings set symbols.enable-external-lookup false' -o r -o bt -o quit
  * frame #0: 0x00007ffff7aa6e75 libc.so.6`.annobin_raise.c + 325
    frame #1: 0x00007ffff7a91895 libc.so.6`.annobin_loadmsgcat.c_end.unlikely + 295
    frame #2: 0x0000000000401140 a.out`func_c at main.c:12:2
    frame #3: 0x000000000040113a a.out`func_b at main.c:18:2
    frame #4: 0x0000000000401134 a.out`func_a at main.c:26:2
    frame #5: 0x000000000040112e a.out`main(argc=<unavailable>, argv=<unavailable>) at main.c:32:2
    frame #6: 0x00007ffff7a92f33 libc.so.6`.annobin_libc_start.c + 243
    frame #7: 0x000000000040106e a.out`.annobin_init.c.hot + 46

The extra ELF symbols are there due to Annobin (I did not investigate why this
problem happened specifically since F-30 and not since F-28).

It is due to:

Symbol table '.dynsym' contains 2361 entries:
Valu e          Size Type   Bind   Vis     Name
0000000000022769   5 FUNC   LOCAL  DEFAULT _nl_load_domain.cold
000000000002276e   0 NOTYPE LOCAL  HIDDEN  .annobin_abort.c.unlikely
...
000000000002276e   0 NOTYPE LOCAL  HIDDEN  .annobin_loadmsgcat.c_end.unlikely
...
000000000002276e   0 NOTYPE LOCAL  HIDDEN  .annobin_textdomain.c_end.unlikely
000000000002276e 548 FUNC   GLOBAL DEFAULT abort
000000000002276e 548 FUNC   GLOBAL DEFAULT abort@@GLIBC_2.2.5
000000000002276e 548 FUNC   LOCAL  DEFAULT __GI_abort
0000000000022992   0 NOTYPE LOCAL  HIDDEN  .annobin_abort.c_end.unlikely

GDB has some more complicated preferences between overlapping and/or sharing
address symbols, I have made here so far the most simple fix for this case.

Differential revision: https://reviews.llvm.org/D63540
2020-01-13 12:05:26 +01:00
Pavel Labath
4023bd05fc [lldb] Add boilerplate to recognize the .debug_rnglists.dwo section 2019-11-26 13:58:26 +01:00
Adrian Prantl
f98606f177 Remove obsolete parameter.
llvm-svn: 374185
2019-10-09 16:55:27 +00:00
Adrian Prantl
939411c1aa Remove the is_mangled flag from Mangled and Symbol
Testing whether a name is mangled or not is extremely cheap and can be
done by looking at the first two characters. Mangled knows how to do
it. On the flip side, many call sites that currently pass in an
is_mangled determination do not know how to correctly do it (for
example, they leave out Swift mangling prefixes).

This patch removes this entry point and just forced Mangled to
determine the mangledness of a string itself.

Differential Revision: https://reviews.llvm.org/D68674

llvm-svn: 374180
2019-10-09 16:22:14 +00:00
Hans Wennborg
1e1e3ba252 Unify the two CRC implementations
David added the JamCRC implementation in r246590. More recently, Eugene
added a CRC-32 implementation in r357901, which falls back to zlib's
crc32 function if present.

These checksums are essentially the same, so having multiple
implementations seems unnecessary. This replaces the CRC-32
implementation with the simpler one from JamCRC, and implements the
JamCRC interface in terms of CRC-32 since this means it can use zlib's
implementation when available, saving a few bytes and potentially making
it faster.

JamCRC took an ArrayRef<char> argument, and CRC-32 took a StringRef.
This patch changes it to ArrayRef<uint8_t> which I think is the best
choice, and simplifies a few of the callers nicely.

Differential revision: https://reviews.llvm.org/D68570

llvm-svn: 374148
2019-10-09 09:06:30 +00:00
Antonio Afonso
ad6690afa3 Explicitly set entry point arch when it's thumb [Second Try]
Summary:
This is a redo of D68069 because I reverted it due to some concerns that were now addressed along with the new comments that @labath added.

I found a case where the main android binary (app_process32) had thumb code at its entry point but no entry in the symbol table indicating this. This made lldb set a 4 byte breakpoint at that address (we default to arm code) instead of a 2 byte one (like we should for thumb).
The big deal with this is that the expression evaluator uses the entry point as a way to know when a JITed expression has finished executing by putting a breakpoint there. Because of this, evaluating expressions on certain android devices (Google Pixel something) made the process crash.
This was fixed by checking this specific situation when we parse the symbol table and add an artificial symbol for this 2 byte range and indicating that it's arm thumb.

I created 2 unit tests for this, one to check that now we know that the entry point is arm thumb, and the other to make sure we didn't change the behaviour for arm code.

I also run the following on the command line with the `app_process32` where I found the issue:
**Before:**
```
(lldb) dis -s 0x1640 -e 0x1644
app_process32[0x1640]: .long  0xf0004668                ; unknown opcode
```
**After:**
```
(lldb) dis -s 0x1640 -e 0x1644
app_process32`:
app_process32[0x1640] <+0>: mov    r0, sp
app_process32[0x1642]:      andeq  r0, r0, r0
```

Reviewers: clayborg, labath, wallace, espindola

Reviewed By: labath

Subscribers: labath, lldb-commits, MaskRay, kristof.beyls, arichardson, emaste, srhines

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D68533

llvm-svn: 374132
2019-10-08 23:44:49 +00:00
Konrad Kleine
2c082b4827 [lldb][ELF] Read symbols from .gnu_debugdata sect.
Summary:
If the .symtab section is stripped from the binary it might be that
there's a .gnu_debugdata section which contains a smaller .symtab in
order to provide enough information to create a backtrace with function
names or to set and hit a breakpoint on a function name.

This change looks for a .gnu_debugdata section in the ELF object file.
The .gnu_debugdata section contains a xz-compressed ELF file with a
.symtab section inside. Symbols from that compressed .symtab section
are merged with the main object file's .dynsym symbols (if any).
In addition we always load the .dynsym even if there's a .symtab
section.

For example, the Fedora and RHEL operating systems strip their binaries
but keep a .gnu_debugdata section. While gdb already can read this
section, LLDB until this patch couldn't. To test this patch on a
Fedora or RHEL operating system, try to set a breakpoint on the "help"
symbol in the "zip" binary. Before this patch, only GDB can set this
breakpoint; now LLDB also can do so without installing extra debug
symbols:

    lldb /usr/bin/zip -b -o "b help" -o "r" -o "bt" -- -h

The above line runs LLDB in batch mode and on the "/usr/bin/zip -h"
target:

    (lldb) target create "/usr/bin/zip"
    Current executable set to '/usr/bin/zip' (x86_64).
    (lldb) settings set -- target.run-args  "-h"

Before the program starts, we set a breakpoint on the "help" symbol:

    (lldb) b help
    Breakpoint 1: where = zip`help, address = 0x00000000004093b0

Once the program is run and has hit the breakpoint we ask for a
backtrace:

    (lldb) r
    Process 10073 stopped
    * thread #1, name = 'zip', stop reason = breakpoint 1.1
        frame #0: 0x00000000004093b0 zip`help
    zip`help:
    ->  0x4093b0 <+0>:  pushq  %r12
        0x4093b2 <+2>:  movq   0x2af5f(%rip), %rsi       ;  + 4056
        0x4093b9 <+9>:  movl   $0x1, %edi
        0x4093be <+14>: xorl   %eax, %eax

    Process 10073 launched: '/usr/bin/zip' (x86_64)
    (lldb) bt
    * thread #1, name = 'zip', stop reason = breakpoint 1.1
      * frame #0: 0x00000000004093b0 zip`help
        frame #1: 0x0000000000403970 zip`main + 3248
        frame #2: 0x00007ffff7d8bf33 libc.so.6`__libc_start_main + 243
        frame #3: 0x0000000000408cee zip`_start + 46

In order to support the .gnu_debugdata section, one has to have LZMA
development headers installed. The CMake section, that controls this
part looks for the LZMA headers and enables .gnu_debugdata support by
default if they are found; otherwise or if explicitly requested, the
minidebuginfo support is disabled.

GDB supports the "mini debuginfo" section .gnu_debugdata since v7.6
(2013).

Reviewers: espindola, labath, jankratochvil, alexshap

Reviewed By: labath

Subscribers: rnkovacs, wuzish, shafik, emaste, mgorny, arichardson, hiraditya, MaskRay, lldb-commits

Tags: #lldb, #llvm

Differential Revision: https://reviews.llvm.org/D66791

llvm-svn: 373891
2019-10-07 10:32:16 +00:00
Antonio Afonso
ae08e479aa Revert "Explicitly set entry point arch when it's thumb"
Backing out because SymbolFile/Breakpad/symtab.test is failing and it seems to be a legit issue. Will investigate.

This reverts commit 72153f95ee4c1b52d2f4f483f0ea4f650ec863be.

llvm-svn: 373687
2019-10-04 01:45:58 +00:00
Antonio Afonso
ac14695804 Explicitly set entry point arch when it's thumb
Summary:
I found a case where the main android binary (app_process32) had thumb code at its entry point but no entry in the symbol table indicating this. This made lldb set a 4 byte breakpoint at that address (we default to arm code) instead of a 2 byte one (like we should for thumb).
The big deal with this is that the expression evaluator uses the entry point as a way to know when a JITed expression has finished executing by putting a breakpoint there. Because of this, evaluating expressions on certain android devices (Google Pixel something) made the process crash.
This was fixed by checking this specific situation when we parse the symbol table and add an artificial symbol for this 2 byte range and indicating that it's arm thumb.

I created 2 unit tests for this, one to check that now we know that the entry point is arm thumb, and the other to make sure we didn't change the behaviour for arm code.

I also run the following on the command line with the `app_process32` where I found the issue:
**Before:**
```
(lldb) dis -s 0x1640 -e 0x1644
app_process32[0x1640]: .long  0xf0004668                ; unknown opcode
```
**After:**
```
(lldb) dis -s 0x1640 -e 0x1644
app_process32`:
app_process32[0x1640] <+0>: mov    r0, sp
app_process32[0x1642]:      andeq  r0, r0, r0
```

Reviewers: clayborg, labath, wallace, espindola

Subscribers: srhines, emaste, arichardson, kristof.beyls, MaskRay, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D68069

llvm-svn: 373680
2019-10-04 00:11:22 +00:00
Konrad Kleine
2f3884ca1d Revert "[LLDB][ELF] Load both, .symtab and .dynsym sections"
This reverts commit 3a4781bbf4.

llvm-svn: 371625
2019-09-11 14:33:37 +00:00
Konrad Kleine
d44c4a71df Revert "[LLDB][ELF] Fixup for comments in D67390"
This reverts commit 813f05915d.

llvm-svn: 371624
2019-09-11 14:33:21 +00:00
Konrad Kleine
813f05915d [LLDB][ELF] Fixup for comments in D67390
llvm-svn: 371600
2019-09-11 10:12:36 +00:00
Konrad Kleine
3a4781bbf4 [LLDB][ELF] Load both, .symtab and .dynsym sections
Summary:
This change ensures that the .dynsym section will be parsed even when there's already is a .symtab.

It is motivated because of minidebuginfo (https://sourceware.org/gdb/current/onlinedocs/gdb/MiniDebugInfo.html#MiniDebugInfo).

There it says:

    Keep all the function symbols not already in the dynamic symbol table.

That means the .symtab embedded inside the .gnu_debugdata does NOT contain the symbols from .dynsym. But in order to put a breakpoint on all symbols we need to load both. I hope this makes sense.

My other patch D66791 implements support for minidebuginfo, that's why I need this change.

Reviewers: labath, espindola, alexshap

Subscribers: JDevlieghere, emaste, arichardson, MaskRay, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D67390

llvm-svn: 371599
2019-09-11 10:00:30 +00:00
Jonas Devlieghere
a8f3ae7c9c [LLDB] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

Differential revision: https://reviews.llvm.org/D66259

llvm-svn: 368933
2019-08-14 22:19:23 +00:00
Pavel Labath
8280730f96 ObjectFileELF: Remove NT_*** constants
llvm now has definitions of those in BinaryFormat/ELF.h. Use those
instead.

llvm-svn: 368159
2019-08-07 12:13:48 +00:00
Pavel Labath
1177bc597d ObjectFileELF: permit thread-local sections with overlapping file addresses
Summary:
In an attempt to make file-address-based lookups more predictable, in D55998
we started ignoring sections which would result in file address
overlaps. It turns out this was too aggressive because thread-local
sections typically will have file addresses which apear to overlap
regular data/code. This does not cause a problem at runtime because
thread-local sections are loaded into memory using special logic, but it
can cause problems for lldb when trying to lookup objects by their file
address.

This patch changes ObjectFileELF to permit thread-local sections to
overlap regular ones by essentially giving them a separate address
space. It also makes them more symmetrical to regular sections by
creating container sections from PT_TLS segments.

Simultaneously, the patch changes the regular file address lookup logic
to ignore sections with the thread-specific bit set. I believe this is
what the users looking up file addresses would typically expect, as
looking up thread-local data generally requires more complex logic (e.g.
DWARF has a special opcode for that).

Reviewers: clayborg, jingham, MaskRay

Subscribers: emaste, aprantl, arichardson, lldb-commits

Differential Revision: https://reviews.llvm.org/D65282

llvm-svn: 368010
2019-08-06 10:04:27 +00:00
Pavel Labath
bfb261baca ObjectFile[ELF]: Refactor gnu_debuglink interface
Summary:
The contents of the gnu_debuglink section were passed through the
GetDebugSymbolFilePaths interface, which was more generic than needed.
As the only class implementing this function is ObjectFileELF, we can
modify the function to return just a single FileSpec (instead of a
list). Also, since the SymbolVendorELF already assumes ELF object files,
we don't have to make this method available on the generic ObjectFile
interface -- instead we can put it on ObjectFileELF directly.

This change also makes is so that if the Module has an explicit symbol
file spec set, we disregard the value the value of the debug link
(instead of doing a secondary lookup using that). I think it makes sense
to honor the users wishes if he had explicitly set the symbol file spec,
and this seems to be consistent with what SymbolVendorMacOSX is doing
(SymbolVendorMacOSX.cpp:125).

The main reason for making these changes is to make the treatment of
build-ids and debug links simpler in the follow-up patch.

Reviewers: clayborg, jankratochvil, mgorny, espindola

Subscribers: emaste, arichardson, MaskRay, lldb-commits

Differential Revision: https://reviews.llvm.org/D65560

llvm-svn: 367824
2019-08-05 09:55:07 +00:00