| Age | Commit message (Collapse) | Author |
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In C++17, static constexpr members are implicitly inline, so they no
longer require an out-of-line definition.
Identified with readability-redundant-declaration.
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Another attempt at resolving the deadlock issue @GeorgeHuyubo discovered
(his previous
[attempt](https://github.com/llvm/llvm-project/pull/160225)).
This change can be summarized as the following:
* Plumb through a boolean flag to force no preload in
`GetOrCreateModules` all the way through to `LoadModuleAtAddress`.
* Parallelize `Module::PreloadSymbols` separately from
`Target::GetOrCreateModule` and its caller `LoadModuleAtAddress` (this
is what avoids the deadlock).
These changes roughly maintain the performance characteristics of the
previous implementation of parallel module loading. Testing on targets
with between 5000 and 14000 modules, I saw similar numbers as before,
often more than 10% faster in the new implementation across multiple
trials for these massive targets. I think it's because we have less lock
contention with this approach.
# The deadlock
See [bt.txt](https://github.com/user-attachments/files/22524471/bt.txt)
for a sample backtrace of LLDB when the deadlock occurs.
As @GeorgeHuyubo explains in his
[PR](https://github.com/llvm/llvm-project/pull/160225), the deadlock
occurs from an ABBA deadlock that happens when a thread context-switches
out of `Module::PreloadSymbols`, goes into `Target::GetOrCreateModule`
for another module, possibly entering this block:
```
if (!module_sp) {
// The platform is responsible for finding and caching an appropriate
// module in the shared module cache.
if (m_platform_sp) {
error = m_platform_sp->GetSharedModule(
module_spec, m_process_sp.get(), module_sp, &search_paths,
&old_modules, &did_create_module);
} else {
error = Status::FromErrorString("no platform is currently set");
}
}
```
`Module::PreloadSymbols` holds a module-level mutex, and then
`GetSharedModule` *attempts* to hold the mutex of the global shared
`ModuleList`. So, this thread holds the module mutex, and waits on the
global shared `ModuleList` mutex.
A competing thread may execute `Target::GetOrCreateModule`, enter the
same block as above, grabbing the global shared `ModuleList` mutex.
Then, in `ModuleList::GetSharedModule`, we eventually call
`ModuleList::FindModules` which eventually waits for the `Module` mutex
held by the first thread (via `Module::GetUUID`). Thus, we deadlock.
## Reproducing the deadlock
It might be worth noting that I've never been able to observe this
deadlock issue during live debugging (e.g. launching or attaching to
processes), however we were able to consistently reproduce this issue
with coredumps when using the following settings:
```
(lldb) settings set target.parallel-module-load true
(lldb) settings set target.preload-symbols true
(lldb) settings set symbols.load-on-demand false
(lldb) target create --core /some/core/file/here
# deadlock happens
```
## How this change avoids this deadlock
This change avoids concurrent executions of `Module::PreloadSymbols`
with `Target::GetOrCreateModule` by waiting until after the
`Target::GetOrCreateModule` executions to run `Module::PreloadSymbols`
in parallel. This avoids the ordering of holding a Module lock *then*
the ModuleList lock, as `Target::GetOrCreateModule` executions maintain
the ordering of the shared ModuleList lock first (from what I've read
and tested).
## Why not read-write lock?
Some feedback in https://github.com/llvm/llvm-project/pull/160225 was to
modify mutexes used in these components with read-write locks. This
might be a good idea overall, but I don't think it would *easily*
resolve this specific deadlock. `Module::PreloadSymbols` would probably
need a write lock to Module, so even if we had a read lock in
`Module::GetUUID` we would still contend. Maybe the `ModuleList` lock
could be a read lock that converts to a write lock if it chooses to
update the module, but it seems likely that some thread would try to
update the shared module list and then the write lock would contend
again.
Perhaps with deeper architectural changes, we could fix this issue?
# Other attempts
One downside of this approach (and the former approach of parallel
module loading) is that each DYLD would need to implement this pattern
themselves. With @clayborg's help, I looked at a few other approaches:
* In `Target::GetOrCreateModule`, backgrounding the
`Module::PreloadSymbols` call by adding it directly to the thread pool
via `Debugger::GetThreadPool().async()`. This required adding a lock to
`Module::SetLoadAddress` (probably should be one there already) since
`ObjectFileELF::SetLoadAddress` is not thread-safe (updates sections).
Unfortunately, during execution, this causes the preload symbols to run
synchronously with `Target::GetOrCreateModule`, preventing us from truly
parallelizing the execution.
* In `Module::PreloadSymbols`, backgrounding the `symtab` and `sym_file`
`PreloadSymbols` calls individually, but similar issues as the above.
* Passing a callback function like
https://github.com/swiftlang/llvm-project/pull/10746 instead of the
boolean I use in this change. It's functionally the same change IMO,
with some design tradeoffs:
* Pro: the caller doesn't need to explicitly call
`Module::PreloadSymbols` itself, and can instead call whatever function
is passed into the callback.
* Con: the caller needs to delay the execution of the callback such that
it occurs after the `GetOrCreateModule` logic, otherwise we run into the
same issue. I thought this would be trickier for the caller, requiring
some kinda condition variable or otherwise storing the calls to execute
afterwards.
# Test Plan:
```
ninja check-lldb
```
---------
Co-authored-by: Tom Yang <toyang@fb.com>
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The new test fails on x86 and arm64 public macOS bots:
```
09:27:59 ======================================================================
09:27:59 FAIL: test_append_frames (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59 Test that we can add frames after real stack.
09:27:59 ----------------------------------------------------------------------
09:27:59 Traceback (most recent call last):
09:27:59 File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 122, in test_append_frames
09:27:59 self.assertEqual(new_frame_count, original_frame_count + 1)
09:27:59 AssertionError: 5 != 6
09:27:59 Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59 ======================================================================
09:27:59 FAIL: test_applies_to_thread (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59 Test that applies_to_thread filters which threads get the provider.
09:27:59 ----------------------------------------------------------------------
09:27:59 Traceback (most recent call last):
09:27:59 File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 218, in test_applies_to_thread
09:27:59 self.assertEqual(
09:27:59 AssertionError: 5 != 1 : Thread with ID 1 should have 1 synthetic frame
09:27:59 Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59 ======================================================================
09:27:59 FAIL: test_prepend_frames (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59 Test that we can add frames before real stack.
09:27:59 ----------------------------------------------------------------------
09:27:59 Traceback (most recent call last):
09:27:59 File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 84, in test_prepend_frames
09:27:59 self.assertEqual(new_frame_count, original_frame_count + 2)
09:27:59 AssertionError: 5 != 7
09:27:59 Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59 ======================================================================
09:27:59 FAIL: test_remove_frame_provider_by_id (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59 Test that RemoveScriptedFrameProvider removes a specific provider by ID.
09:27:59 ----------------------------------------------------------------------
09:27:59 Traceback (most recent call last):
09:27:59 File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 272, in test_remove_frame_provider_by_id
09:27:59 self.assertEqual(thread.GetNumFrames(), 3, "Should have 3 synthetic frames")
09:27:59 AssertionError: 5 != 3 : Should have 3 synthetic frames
09:27:59 Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59 ======================================================================
09:27:59 FAIL: test_replace_all_frames (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59 Test that we can replace the entire stack.
09:27:59 ----------------------------------------------------------------------
09:27:59 Traceback (most recent call last):
09:27:59 File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 41, in test_replace_all_frames
09:27:59 self.assertEqual(thread.GetNumFrames(), 3, "Should have 3 synthetic frames")
09:27:59 AssertionError: 5 != 3 : Should have 3 synthetic frames
09:27:59 Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59 ======================================================================
09:27:59 FAIL: test_scripted_frame_objects (TestScriptedFrameProvider.ScriptedFrameProviderTestCase)
09:27:59 Test that provider can return ScriptedFrame objects.
09:27:59 ----------------------------------------------------------------------
09:27:59 Traceback (most recent call last):
09:27:59 File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/scripted_frame_provider/TestScriptedFrameProvider.py", line 159, in test_scripted_frame_objects
09:27:59 self.assertEqual(frame0.GetFunctionName(), "custom_scripted_frame_0")
09:27:59 AssertionError: 'thread_func(int)' != 'custom_scripted_frame_0'
09:27:59 - thread_func(int)
09:27:59 + custom_scripted_frame_0
09:27:59
09:27:59 Config=arm64-/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/lldb-build/bin/clang
09:27:59 ----------------------------------------------------------------------
09:27:59 Ran 6 tests in 14.242s
09:27:59
09:27:59 FAILED (failures=6)
```
Reverts llvm/llvm-project#161870
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This patch extends ScriptedFrame to work with real (non-scripted)
threads,
enabling frame providers to synthesize frames for native processes.
Previously, ScriptedFrame only worked within
ScriptedProcess/ScriptedThread
contexts. This patch decouples ScriptedFrame from ScriptedThread,
allowing
users to augment or replace stack frames in real debugging sessions for
use
cases like custom calling conventions, reconstructing corrupted frames
from
core files, or adding diagnostic frames.
Key changes:
- ScriptedFrame::Create() now accepts ThreadSP instead of requiring
ScriptedThread, extracting architecture from the target triple rather
than ScriptedProcess.arch
- Added SBTarget::RegisterScriptedFrameProvider() and
ClearScriptedFrameProvider() APIs, with Target storing a
SyntheticFrameProviderDescriptor template for new threads
- Added "target frame-provider register/clear" commands for CLI access
- Thread class gains LoadScriptedFrameProvider(),
ClearScriptedFrameProvider(),
and GetFrameProvider() methods for per-thread frame provider management
- New SyntheticStackFrameList overrides FetchFramesUpTo() to lazily
provide
frames from either the frame provider or the real stack
This enables practical use of the SyntheticFrameProvider infrastructure
in
real debugging workflows.
rdar://161834688
Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
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We're iterating over the stop hooks so if one of them changes the stop
hook list by deleting itself or another stop hook, that invalidates our
iterator.
I chose to fix this by making a copy of the stop hook list and iterating
over that. That's a cheap operation since this is just an array of
shared pointers. But more importantly doing it this way means that if on
a stop where one stop hook deletes another, the deleted hook will always
get a chance to run. If you iterated over the list itself, then whether
that to be deleted hook gets to run would be dependent on whether it was
before or after the deleting stop hook, which would be confusing.
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Main executables were bypassing the locate module callback that shared
libraries use, preventing custom symbol file location logic from working
consistently.
This PR fix this by
* Adding target context to ModuleSpec
* Leveraging that context to use target search path and platform's
locate module callback in ModuleList::GetSharedModule
This ensures both main executables and shared libraries get the same
callback treatment for symbol file resolution.
---------
Co-authored-by: George Hu <hyubo@meta.com>
Co-authored-by: George Hu <georgehuyubo@gmail.com>
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This avoids unintentional comparisons between `SourceLanguage` and
`LanguageType`.
Also marks `operator bool` explicit so we don't implicitly convert to
bool.
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This commit aggregates the following changes:
1. Fix the format (i.e., indentation) when printing stop hooks via `target
stop-hook list`.
2. Add `IndentScope Stream::MakeIndentScope()` to make managing (and restoring!)
of the indentation level on `Stream` instances more ergonomic and less error
prone.
3. Simplify printing of stop hooks using the new `IndentScope`.
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eliminate code duplication (#164739)
### Summary
This PR refactors breakpoint event notification in LLDB to centralize
and eliminate code duplication. It creates a unified method in the
`Target` class for sending breakpoint change events. The new methods
check if listeners exist before broadcasting events
### Test
<img width="1532" height="76" alt="Screenshot 2025-10-23 at 12 49 31 PM"
src="https://github.com/user-attachments/assets/6d6a6da6-9684-463c-aeeb-90663cdbd077"
/>
---------
Co-authored-by: Piyush Jaiswal <piyushjais@meta.com>
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Introduce the concept of internal stop hooks.
These are similar to LLDB's internal breakpoints:
LLDB itself will add them and users of LLDB will
not be able to add or remove them.
This change adds the following 3
independently-useful concepts:
* Maintain a list of internal stop hooks that will be populated by LLDB
and cannot be added to or removed from by users. They are managed in a
separate list in `Target::m_internal_stop_hooks`.
* `StopHookKind:CodeBased` and `StopHookCoded` represent a stop hook
defined by a C++ code callback (instead of command line expressions or a
Python class).
* Stop hooks that do not print any output can now also suppress the
printing of their header and description when they are hit via
`StopHook::GetSuppressOutput`.
Combining these 3 concepts we can model "internal
stop hooks" which serve the same function as
LLDB's internal breakpoints: executing built-in,
LLDB-defined behavior, leveraging the existing
mechanism of stop hooks.
This change also simplifies
`Target::RunStopHooks`. We already have to
materialize a new list for combining internal and
user stop hooks. Filter and only add active hooks to this list to avoid
the need for "isActive?"
checks later on.
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This fixes a potential use after free where
ModuleList::RemoveSharedModuleIfOrphaned ->
SharedModuleList::RemoveIfOrphaned -> SharedModuleList::RemoveFromMap
would potentially dereference a freed pointer. This fixes it by not
calling ModuleList::RemoveSharedModuleIfOrphaned at all if the pointer
was just freed.
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### Summary
Add support for unique target ids per Target instance. This is needed
for upcoming changes to allow debugger instances to be shared across
separate DAP instances for child process debugging. We want the IDE to
be able to attach to existing targets in an already runny lldb-dap
session, and having a unique ID per target would make that easier.
Each Target instance will have its own unique id, and uses a
function-local counter in `TargetList::CreateTargetInternal` to assign
incremental unique ids.
### Tests
Added several unit tests to test basic functionality, uniqueness of
targets, and target deletion doesn't affect the uniqueness.
```
bin/lldb-dotest -p TestDebuggerAPI
```
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Resolves #141955
- Adds data to breakpoints `Source` object, in order for assembly
breakpoints, which rely on a temporary `sourceReference` value, to be
able to resolve in future sessions like normal path+line breakpoints
- Adds optional `instructions_offset` parameter to `BreakpointResolver`
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(#150720)
This is NFC, I'm modernizing the interface before I add to it in a
subsequent commit.
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(#149620)
Target::ReadMemory may or may not read live memory, but whether it did
read from live memory or from the filecache is opaque to callers. Add an
extra out parameter to indicate whether live memory was read or not.
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c72c0b298c13 fixed a race condition in Target::GetExecutableModule. The
patch originally added the lock_guard but I suggested using the locking
ModuleList::Modules() helper instead. That didn't consider that the
fallback would still access the ModuleList without holding the lock.
This patch fixes the remaining issue.
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(#145111)
…ess" (#144810)
This relands commit e0933ab5ae4856c4aa188a5ea16716b3a8d0840b. The
original commit was causing the test TestCreateAfterAttach.py to fail on
ARM Ubuntu bots. It's possible that this could've been happening because
the test for wait-attach progress reporting is waiting on a process
named "a.out" which could be too generic as multiple other tests (when
run in parallel on the bots) could also be using processes named
"a.out". This commit changes the wait-attach progress report test to
wait on a unique process name.
Original PR description:
This commit adds a progress report when wait-attaching to a process as
well as a test for this.
Original PR link: https://github.com/llvm/llvm-project/pull/144768
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(#144810)
This is breaking TestCreateAfterAttach.py on Ubuntu:
```
======================================================================
FAIL: test_create_after_attach_dwo (TestCreateAfterAttach.CreateAfterAttachTestCase.test_create_after_attach_dwo)
Test thread creation after process attach.
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 1804, in test_method
return attrvalue(self)
^^^^^^^^^^^^^^^
File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/decorators.py", line 149, in wrapper
return func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^
File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/test/API/functionalities/thread/create_after_attach/TestCreateAfterAttach.py", line 36, in test_create_after_attach
self.runCmd("process attach -p " + str(pid))
File "/home/buildbot/worker/as-builder-9/lldb-remote-linux-ubuntu/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 1005, in runCmd
self.assertTrue(self.res.Succeeded(), msg + output)
AssertionError: False is not true : Command 'process attach -p 1474309' did not return successfully
Error output:
error: attach failed: lost connection
```
on the buildbots for lldb-remote-linux-ubuntu, lldb-arm-ubuntu,
lldb-aarch64-ubuntu, lldb-arm-ubuntu.
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This commit adds a progress report when wait-attaching to a process as
well as a test for this.
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Since this PR: https://github.com/llvm/llvm-project/pull/141670/ We
started to override the Platform/Arch for a target if needed. However we
may have already registered locate module callback with the old
platform.
This PR will move the locate module callback to the new Platform
whenever Target changes architecture.
Co-authored-by: George Hu <georgehuyubo@gmail.com>
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Use the locking iterator to ensure module don't change during iteration.
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We're reading from the object's vtable to determine the pointer to the
full object. The vtable is normally in the "rodata" section of the
executable, which is often not included in the core file because it's
not supposed to change and the debugger can extrapolate its contents
from the executable file. We weren't doing that.
This patch changes the read operation to use the target class (which
falls back onto the executable module as expected) and adds the missing
ReadSignedIntegerFromMemory API. The fix is tested by creating a core
(minidump) file which deliberately omits the vtable pointer.
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stop-hooks are supposed to trigger every time the process stops, but as
initially implemented they would only fire when control was returned to
the user. So for instance when a process was launched the stop hook
would only trigger when the process hit a breakpoint or crashed.
However, it would be really useful to be able to trigger a stop hook
when lldb first gains control over the process. One way to do that would
be to implement general "target lifecycle events" and then send process
created events that users could bind actions to.
OTOH, extending the stop hooks to fire when lldb first gains control
over the process is a pretty natural extension to the notion of a stop
hook. So this patch takes the shorter route to that ability by making
stop-hooks fire when lldb first gains control over the process.
I also added the ability to specify whether to trigger the stop hook "on
gaining control". I'm on the fence about whether to set the default to
be "trigger on gaining control" or "don't trigger on gaining control".
Since I think it's a generally useful feature, I've set the default to
"trigger on gaining control".
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Follow-up fix discussed here:
https://github.com/llvm/llvm-project/pull/129578#issuecomment-2695838042
---------
Co-authored-by: Jim Ingham <jingham@apple.com>
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This patch improves LLDB launch time on Linux machines for **preload
scenarios**, particularly for executables with a lot of shared library
dependencies (or modules). Specifically:
* Launching a binary with `target.preload-symbols = true`
* Attaching to a process with `target.preload-symbols = true`.
It's completely controlled by a new flag added in the first commit
`plugin.dynamic-loader.posix-dyld.parallel-module-load`, which *defaults
to false*. This was inspired by similar work on Darwin #110646.
Some rough numbers to showcase perf improvement, run on a very beefy
machine:
* Executable with ~5600 modules: baseline 45s, improvement 15s
* Executable with ~3800 modules: baseline 25s, improvement 10s
* Executable with ~6650 modules: baseline 67s, improvement 20s
* Executable with ~12500 modules: baseline 185s, improvement 85s
* Executable with ~14700 modules: baseline 235s, improvement 120s
A lot of targets we deal with have a *ton* of modules, and unfortunately
we're unable to convince other folks to reduce the number of modules, so
performance improvements like this can be very impactful for user
experience.
This patch achieves the performance improvement by parallelizing
`DynamicLoaderPOSIXDYLD::RefreshModules` for the launch scenario, and
`DynamicLoaderPOSIXDYLD::LoadAllCurrentModules` for the attach scenario.
The commits have some context on their specific changes as well --
hopefully this helps the review.
# More context on implementation
We discovered the bottlenecks by via `perf record -g -p <lldb's pid>` on
a Linux machine. With an executable known to have 1000s of shared
library dependencies, I ran
```
(lldb) b main
(lldb) r
# taking a while
```
and showed the resulting perf trace (snippet shown)
```
Samples: 85K of event 'cycles:P', Event count (approx.): 54615855812
Children Self Command Shared Object Symbol
- 93.54% 0.00% intern-state libc.so.6 [.] clone3
clone3
start_thread
lldb_private::HostNativeThreadBase::ThreadCreateTrampoline(void*) r
std::_Function_handler<void* (), lldb_private::Process::StartPrivateStateThread(bool)::$_0>::_M_invoke(std::_Any_data const&)
lldb_private::Process::RunPrivateStateThread(bool) n
- lldb_private::Process::HandlePrivateEvent(std::shared_ptr<lldb_private::Event>&)
- 93.54% lldb_private::Process::ShouldBroadcastEvent(lldb_private::Event*)
- 93.54% lldb_private::ThreadList::ShouldStop(lldb_private::Event*)
- lldb_private::Thread::ShouldStop(lldb_private::Event*) *
- 93.53% lldb_private::StopInfoBreakpoint::ShouldStopSynchronous(lldb_private::Event*) t
- 93.52% lldb_private::BreakpointSite::ShouldStop(lldb_private::StoppointCallbackContext*) i
lldb_private::BreakpointLocationCollection::ShouldStop(lldb_private::StoppointCallbackContext*) k
lldb_private::BreakpointLocation::ShouldStop(lldb_private::StoppointCallbackContext*) b
lldb_private::BreakpointOptions::InvokeCallback(lldb_private::StoppointCallbackContext*, unsigned long, unsigned long) i
DynamicLoaderPOSIXDYLD::RendezvousBreakpointHit(void*, lldb_private::StoppointCallbackContext*, unsigned long, unsigned lo
- DynamicLoaderPOSIXDYLD::RefreshModules() O
- 93.42% DynamicLoaderPOSIXDYLD::RefreshModules()::$_0::operator()(DYLDRendezvous::SOEntry const&) const u
- 93.40% DynamicLoaderPOSIXDYLD::LoadModuleAtAddress(lldb_private::FileSpec const&, unsigned long, unsigned long, bools
- lldb_private::DynamicLoader::LoadModuleAtAddress(lldb_private::FileSpec const&, unsigned long, unsigned long, boos
- 83.90% lldb_private::DynamicLoader::FindModuleViaTarget(lldb_private::FileSpec const&) o
- 83.01% lldb_private::Target::GetOrCreateModule(lldb_private::ModuleSpec const&, bool, lldb_private::Status*
- 77.89% lldb_private::Module::PreloadSymbols()
- 44.06% lldb_private::Symtab::PreloadSymbols()
- 43.66% lldb_private::Symtab::InitNameIndexes()
...
```
We saw that majority of time was spent in `RefreshModules`, with the
main culprit within it `LoadModuleAtAddress` which eventually calls
`PreloadSymbols`.
At first, `DynamicLoaderPOSIXDYLD::LoadModuleAtAddress` appears fairly
independent -- most of it deals with different files and then getting or
creating Modules from these files. The portions that aren't independent
seem to deal with ModuleLists, which appear concurrency safe. There were
members of `DynamicLoaderPOSIXDYLD` I had to synchronize though: namely
`m_loaded_modules` which `DynamicLoaderPOSIXDYLD` maintains to map its
loaded modules to their link addresses. Without synchronizing this, I
ran into SEGFAULTS and other issues when running `check-lldb`. I also
locked the assignment and comparison of `m_interpreter_module`, which
may be unnecessary.
# Alternate implementations
When creating this patch, another implementation I considered was
directly background-ing the call to `Module::PreloadSymbol` in
`Target::GetOrCreateModule`. It would have the added benefit of working
across platforms generically, and appeared to be concurrency safe. It
was done via `Debugger::GetThreadPool().async` directly. However, there
were a ton of concurrency issues, so I abandoned that approach for now.
# Testing
With the feature active, I tested via `ninja check-lldb` on both Debug
and Release builds several times (~5 or 6 altogether?), and didn't spot
additional failing or flaky tests.
I also tested manually on several different binaries, some with around
14000 modules, but just basic operations: launching, reaching main,
setting breakpoint, stepping, showing some backtraces.
I've also tested with the flag off just to make sure things behave
properly synchronously.
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New changes: add check to avoid accessing invalid obj
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target (#127834)"
This reverts commit 04e39ce3fddaaec41d9c7babcca55133d7e49969 due to test
breakage.
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Co-authored-by: Pavel Labath <pavel@labath.sk>
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Introduce `StopHookResult::NoPreference` and
simplify control flow in `Target::RunStopHooks()`.
The algorithm is (in order):
1. "Auto continue" set on any hook -> continue
2. "Stop demanded" by any hook -> stop
3. "Continue requested" by any hook -> continue
4. No hooks, or "no preference" only (default
stance) -> stop
The new `NoPreference` lets us keep the default
stance, distinguishing case 3. and 4.
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We didn't also copy over the next stop hook id, which meant we would
overwrite the stop hooks from the dummy target with stop hooks set after
they are copied over.
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Remove Debugger::GetOutputStream and Debugger::GetErrorStream in
preparation for replacing both with a new variant that needs to be
locked and hence can't be handed out like we do right now.
The patch replaces most uses with GetAsyncOutputStream and
GetAsyncErrorStream respectively. There methods return new StreamSP
objects that automatically get flushed on destruction.
See #126630 for more details.
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Lots of code around LLDB was directly accessing the target's section
load list. This NFC patch makes the section load list private so the
Target class can access it, but everyone else now uses accessor
functions. This allows us to control the resolving of addresses and will
allow for functionality in LLDB which can lazily resolve addresses in
JIT plug-ins with a future patch.
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Compared to the python version, this also does type checking and error
handling, so it's slightly longer, however, it's still comfortably
under 500 lines.
Relanding with more explicit type conversions.
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This reverts commit f6012a209dca6b1866d00e6b4f96279469884320.
Revert "[lldb] Add cast to fix compile error on 32-but platforms"
This reverts commit d300337e93da4ed96b044557e4b0a30001967cf0.
Revert "[lldb] Improve log message to include missing strings"
This reverts commit 0be33484853557bc0fd9dfb94e0b6c15dda136ce.
Revert "[lldb] Add comment"
This reverts commit e2bb47443d2e5c022c7851dd6029e3869fc8835c.
Revert "[lldb] Implement a formatter bytecode interpreter in C++"
This reverts commit 9a9c1d4a6155a96ce9be494cec7e25731d36b33e.
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Compared to the python version, this also does type checking and error
handling, so it's slightly longer, however, it's still comfortably
under 500 lines.
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Add support for type summaries embedded into the binary.
These embedded summaries will typically be generated by Swift macros,
but can also be generated by any other means.
rdar://115184658
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(#117186)
Prior to this patch, the function returned an exit status, sometimes a
ValueObject with an error and a Status object. This patch removes the
Status object and ensures the error is consistently returned as the
error of the ValueObject.
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"statistics dump" currently report the statistics of all targets in
debugger instead of current target. This is wrong because there is a
"statistics dump --all-targets" option that supposed to include
everything.
This PR fixes the issue by only report statistics for current target
instead of all. It also includes the change to reset statistics debug
info/symbol table parsing/indexing time during debugger destroy. This is
required so that we report current statistics if we plan to reuse
lldb/lldb-dap across debug sessions
---------
Co-authored-by: jeffreytan81 <jeffreytan@fb.com>
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Add the framework code for hooking up and calling the Data Inspection
Language (DIL) implementation, as an alternate implementation for the
'frame variable' command. For now, this is an opt-in option, via a
target setting 'target.experimental.use-DIL'. See
https://discourse.llvm.org/t/rfc-data-inspection-language/69893 for more
information about this project.
This PR does not actually call any of the DIL code; instead the piece
that will eventually call the DIL code
(StackFrame::DILEvaluateVariableExpression) calls back into the original
'frame variable' implementation.
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Add the ability to override the disassembly CPU and CPU features through
a target setting (`target.disassembly-cpu` and
`target.disassembly-features`) and a `disassemble` command option
(`--cpu` and `--features`).
This is especially relevant for architectures like RISC-V which relies
heavily on CPU extensions.
The majority of this patch is plumbing the options through. I recommend
looking at DisassemblerLLVMC and the test for the observable change in
behavior.
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This retries the PR 113521 skipping a test in a remote environment.
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Reverts llvm/llvm-project#113521 due to build bot failures mentioned in
the original PR.
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Internally we use bazel in a way in which it can drop you in a LLDB
session with the target launched in a particular cwd, which is needed
for things to work. We've been making this automation work via `process
launch -w`. However, if later the user wants to restart the process with
`r`, then they end up using a different cwd for relaunching the process.
As a way to fix this, I'm adding a target-level setting that allows
configuring a default cwd used for launching the process without needing
the user to specify it manually.
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Create dependent modules in parallel in Target::SetExecutableModule.
This change was inspired by #110646 which takes the same approach when
attaching. Jason suggested we could use the same approach when you
create a target in LLDB.
I used Slack for benchmarking, which loads 902 images.
```
Benchmark 1: ./bin/lldb /Applications/Slack.app/Contents/MacOS/Slack
Time (mean ± σ): 1.225 s ± 0.003 s [User: 3.977 s, System: 1.521 s]
Range (min … max): 1.220 s … 1.229 s 10 runs
Benchmark 2: ./bin/lldb /Applications/Slack.app/Contents/MacOS/Slack
Time (mean ± σ): 3.253 s ± 0.037 s [User: 3.013 s, System: 0.248 s]
Range (min … max): 3.211 s … 3.310 s 10 runs
```
We see about a 2x speedup, which matches what Jason saw for the attach
scenario. I also ran this under TSan to confirm this doesn't introduce
any races or deadlocks.
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This reverts commit b360dfd5031e76c97257ef1b3e90385bf297e8ab.
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Create dependent modules in parallel in Target::SetExecutableModule.
This change was inspired by #110646 which takes the same approach when
attaching. Jason suggested we could use the same approach when you
create a target in LLDB.
I used Slack for benchmarking, which loads 902 images.
```
Benchmark 1: ./bin/lldb /Applications/Slack.app/Contents/MacOS/Slack
Time (mean ± σ): 1.225 s ± 0.003 s [User: 3.977 s, System: 1.521 s]
Range (min … max): 1.220 s … 1.229 s 10 runs
Benchmark 2: ./bin/lldb /Applications/Slack.app/Contents/MacOS/Slack
Time (mean ± σ): 3.253 s ± 0.037 s [User: 3.013 s, System: 0.248 s]
Range (min … max): 3.211 s … 3.310 s 10 runs
```
We see about a 2x speedup, which matches what Jason saw for the attach
scenario. I also ran this under TSan to confirm this doesn't introduce
any races or deadlocks.
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ValueObject is part of lldbCore for historical reasons, but conceptually
it deserves to be its own library. This does introduce a (link-time) circular
dependency between lldbCore and lldbValueObject, which is unfortunate
but probably unavoidable because so many things in LLDB rely on
ValueObject. We already have cycles and these libraries are never built
as dylibs so while this doesn't improve the situation, it also doesn't
make things worse.
The header includes were updated with the following command:
```
find . -type f -exec sed -i.bak "s%include \"lldb/Core/ValueObject%include \"lldb/ValueObject/ValueObject%" '{}' \;
```
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