This reverts commit 5778ada8e5.
The watchpoint tests all stall on aarch64-ubuntu bots. Reverting till I can
get my hands on an system to test this out.
This reverts commit 555ae5b8f5.
Apparently, there's something different about how Linux ARM handles watchpoints,
as all the watchpoint tests seem to stall on the Ubuntu aarch64 bots.
Reverting till I can get my hands on a linux system and see what is
wrong.
That was causing hit counts to be double-counted on x86_64 Linux.
It looks like StopInfoWatchpoint::ShouldStopSynchronous gets called
twice for a give stop on Linux (not on Darwin). I had taken out the
"have I been called already" check when I reworked this part of the
code because it didn't seem necessary. Putting that back in because
it looks like it is on some systems.
Since we want to present the "new & old" values for watchpoint hits, on architectures,
including the ARM family, that stop before the triggering instruction is run, we need
to single step over the instruction before stopping for realz. This was incorrectly
done directly in the StopInfoWatchpoint::ShouldStop. That causes problems if more than
one thread stops "for a reason" at the same time as the watchpoint, since the other actions
didn't expect the process to make progress in this part of the execution control machinery.
The correct way to do this is to schedule the step over using ThreadPlans, and then to restore
the stop info after that plan stops, so that the rest of the stop info actions can happen when
all the other threads have handled their immediate actions as well.
Differential Revision: https://reviews.llvm.org/D129814
Thanks to ymeng@fb.com for coming up with this change.
`thread trace dump info` can dump some metrics that can be useful for
analyzing the performance and quality of a trace. This diff adds a --json
option for dumping this information in json format that can be easily
understood my machines.
Differential Revision: https://reviews.llvm.org/D129332
Thanks to fredzhou@fb.com for coming up with this feature.
When tracing in per-cpu mode, we have information of in which cpu we are execution each instruction, which comes from the context switch trace. This diff makes this information available as a `cpu changed event`, which an additional accessor in the cursor `GetCPU()`. As cpu changes are very infrequent, any consumer should listen to cpu change events instead of querying the actual cpu of a trace item. Once a cpu change event is seen, the consumer can invoke GetCPU() to get that information. Also, it's possible to invoke GetCPU() on an arbitrary instruction item, which will return the last cpu seen. However, this call is O(logn) and should be used sparingly.
Manually tested with a sample program that starts on cpu 52, then goes to 18, and then goes back to 52.
Differential Revision: https://reviews.llvm.org/D129340
In rare situations, disassemblying would fail that produce an invalid
InstructionSP object. We need to check that it's valid before using.
With this change, now the dumper doesn't crash with dumping instructions of
ioctl. In fact, it now dumps this output
{
"id": 6135,
"loadAddress": "0x7f4bfe5c7515",
"module": "libc.so.6",
"symbol": "ioctl",
"source": "glibc/2.34/src/glibc-2.34/sysdeps/unix/syscall-template.S",
"line": 120,
"column": 0
}
Anyway, we need to investigate why the diassembler failed disassembling that
instruction. From over 2B instructions I was disassembling today, just this
one failed, so this could be a bug in LLVM's core disassembler.
Differential Revision: https://reviews.llvm.org/D129588
not to be hit. But another thread might be hit at the same time and
actually stop. So we have to be sure to switch the first thread's
stop info to eStopReasonNone or we'll report a hit when the condition
failed, which is confusing.
Differential Revision: https://reviews.llvm.org/D128776
We want to include events with metadata, like context switches, and this
requires the API to handle events with payloads (e.g. information about
such context switches). Besides this, we want to support multiple
similar events between two consecutive instructions, like multiple
context switches. However, the current implementation is not good for this because
we are defining events as bitmask enums associated with specific
instructions. Thus, we need to decouple instructions from events and
make events actual items in the trace, just like instructions and
errors.
- Add accessors in the TraceCursor to know if an item is an event or not
- Modify from the TraceDumper all the way to DecodedThread to support
- Renamed the paused event to disabled.
- Improved the tsc handling logic. I was using an API for getting the tsc from libipt, but that was an overkill that should be used when not processing events manually, but as we are already processing events, we can more easily get the tscs.
event items. Fortunately this simplified many things
- As part of this refactor, I also fixed and long stating issue, which is that some non decoding errors were being inserted in the decoded thread. I changed this so that TraceIntelPT::Decode returns an error if the decoder couldn't be set up proplerly. Then, errors within a trace are actual anomalies found in between instrutions.
All test pass
Differential Revision: https://reviews.llvm.org/D128576
The current way ot traversing the cursor is a bit uncommon and it can't handle empty traces, in fact, its invariant is that it shold always point to a valid item. This diff simplifies the cursor API and allows it to point to invalid items, thus being able to handle empty traces or to know it ran out of data.
- Removed all the granularity functionalities, because we are not actually making use of that. We can bring them back when they are actually needed.
- change the looping logic to the following:
```
for (; cursor->HasValue(); cursor->Next()) {
if (cursor->IsError()) {
.. do something for error
continue;
}
.. do something for instruction
}
```
- added a HasValue method that can be used to identify if the cursor ran out of data, the trace is empty, or the user tried to move to an invalid position via SetId() or Seek()
- made several simplifications to severals parts of the code.
Differential Revision: https://reviews.llvm.org/D128543
As previously discussed with @jj10306, we didn't really have a name for
the post-mortem (or offline) trace session representation, which is in
fact a folder with a bunch of files. We decided to call this folder
"trace bundle", and the main JSON file in it "trace bundle description
file". This naming is pretty decent, so I'm refactoring all the existing
code to account for that.
Differential Revision: https://reviews.llvm.org/D128484
In order to provide simple scripting support on top of instruction traces, a simple solution is to enhance the `dump instructions` command and allow printing in json and directly to a file. The format is verbose and not space efficient, but it's not supposed to be used for really large traces, in which case the TraceCursor API is the way to go.
- add a -j option for printing the dump in json
- add a -J option for pretty printing the json output
- add a -F option for specifying an output file
- add a -a option for dumping all the instructions available starting at the initial point configured with the other flags
- add tests for all cases
- refactored the instruction dumper and abstracted the actual "printing" logic. There are two writer implementations: CLI and JSON. This made the dumper itself much more readable and maintanable
sample output:
```
(lldb) thread trace dump instructions -t -a --id 100 -J
[
{
"id": 100,
"tsc": "43591204528448966"
"loadAddress": "0x407a91",
"module": "a.out",
"symbol": "void std::deque<Foo, std::allocator<Foo>>::_M_push_back_aux<Foo>(Foo&&)",
"mnemonic": "movq",
"source": "/usr/include/c++/8/bits/deque.tcc",
"line": 492,
"column": 30
},
...
```
Differential Revision: https://reviews.llvm.org/D128316
This fixes an issue that, when you start lldb or use `target create`
with a program name which is on $PATH, or not specify the .exe suffix of
a program in the working directory on Windows, you get a confusing
error, for example:
(lldb) target create notepad
error: 'C:\WINDOWS\SYSTEM32\notepad.exe' doesn't contain any 'host'
platform architectures: i686, x86_64, i386, i386
Fixes https://github.com/mstorsjo/llvm-mingw/issues/265
Reviewed By: DavidSpickett
Differential Revision: https://reviews.llvm.org/D127436
Add a setting to configure how LLDB parses dynamic Objective-C class
metadata. By default LLDB will choose the most appropriate method for
the target OS.
Differential revision: https://reviews.llvm.org/D128312
Add trace load functionality to SBDebugger via the `LoadTraceFromFile` method.
Update intelpt test case class to have `testTraceLoad` method so we can take advantage of
the testApiAndSB decorator to test both the CLI and SB without duplicating code.
Differential Revision: https://reviews.llvm.org/D128107
When we hit a breakpoint site all of whose owners are internal, we don't
broadcast that event to the public event queue. However, we were checking
whether that was true in the ShouldNotify method, which gets run after the
breakpoint callbacks get run. If the breakpoint callback deletes the site
we just hit, we no longer have the information to make that determination.
This patch just gathers the "was all internal" fact when the StopInfoBreakpoint
gets made, which happens before anyone has a chance to delete the site, and then
uses that cached value.
This bug was causing a couple of tests (including TestStopAtEntry.py) to fail
when using new the macOS Ventura dyld support.
Differential Revision: https://reviews.llvm.org/D127997
Having a member variable TraceIntelPT * makes it look as if it was
optional. I'm using instead a weak_ptr to indicate that it's not
optional and the object is under the ownership of TraceIntelPT.
Besides that, I've simplified the Perf aux and data buffers copying by
using vector.insert.
I'm also renaming Lookup2 to Lookup. The 2 in the name is confusing.
Differential Revision: https://reviews.llvm.org/D127881
As discusses offline with @jj10305, we are updating some naming used throughout the code, specially in the json schema
- traceBuffer -> iptTrace
- core -> cpu
Differential Revision: https://reviews.llvm.org/D127817
This applies the changes requested for diff 12.
- use DenseMap<ConstString, _> instead of std::unordered_map<ConstString, _>, which is more idiomatic and possibly performant.
- deduplicate some code in Trace.cpp by using helper functions for fetching in maps
- stop using size and offset when fetching binary data, because we in fact read the entire buffers all the time. If we ever need streaming, we can implement it then. Now, the size is used only to check that we are getting the correct amount of data. This is useful because in some cases determining the size doesn't involve fetching the actual data.
- added back the x86_64 macro to the perf tests
- added more documentation
- simplified some file handling
- fixed some comments
Differential Revision: https://reviews.llvm.org/D127752
This improves several things and addresses comments up to the diff [11] in this stack.
- Simplify many functions to receive less parameters that they can identify easily
- Create Storage classes for Trace and TraceIntelPT that can make it easier to reason about what can change with live process refreshes and what cannot.
- Don't cache the perf zero conversion numbers in lldb-server to make sure we get the most up-to-date numbers.
- Move the thread identifaction from context switches to the bundle parser, to leave TraceIntelPT simpler. This also makes sure that the constructor of TraceIntelPT is invoked when the entire data has been checked to be correct.
- Normalize all bundle paths before the Processes, Threads and Modules are created, so that they can assume that all paths are correct and absolute
- Fix some issues in the tests. Now they all pass.
- return the specific instance when constructing PerThread and MultiCore processor tracers.
- Properly implement IntelPTMultiCoreTrace::TraceStart.
- Improve some comments.
- Use the typedef ContextSwitchTrace more often for clarity.
- Move CreateContextSwitchTracePerfEvent to Perf.h as a utility function.
- Synchronize better the state of the context switch and the intel pt
perf events.
- Use a booblean instead of an enum for the PerfEvent state.
Differential Revision: https://reviews.llvm.org/D127456
For some context, The context switch data contains information of which threads were
executed by each traced process, therefore it's not necessary to specify
them in the trace file.
So this diffs adds support for that automatic feature. Eventually we
could include it to live processes as well.
Differential Revision: https://reviews.llvm.org/D127001
This is the final functional patch to support intel pt decoding per cpu.
It works by doing the following:
- First, all context switches are split by tid and sorted in order. This produces a list of continuous executes per thread per core.
- Then, all intel pt subtraces are split by PSB boundaries and assigned to individual thread continuous executions on the same core by doing simple TSC-based comparisons.
- With this, we have, per thread, a sorted list of continuous executions each one with a list of intel pt subtraces. Up to this point, this is really fast because no instructions were actually decoded.
- Then, each thread can be decoded by traversing their continuous executions and intel pt subtraces. An advantage of having these continuous executions is that we can identify if a continuous exexecution doesn't have intel pt data, and thus has a gap in it. We can later to more sofisticated comparisons to identify if within a continuous execution there are gaps.
I'm adding a test as well.
Differential Revision: https://reviews.llvm.org/D126394
- Add the logic that parses all cpu context switch traces and produces blocks of continuous executions, which will be later used to assign intel pt subtraces to threads and to identify gaps. This logic can also identify if the context switch trace is malformed.
- The continuous executions blocks are able to indicate when there were some contention issues when producing the context switch trace. See the inline comments for more information.
- Update the 'dump info' command to show information and stats related to the multicore decoding flow, including timing about context switch decoding.
- Add the logic to conver nanoseconds to TSCs.
- Fix a bug when returning the context switches. Now they data returned makes sense and even empty traces can be returned from lldb-server.
- Finish the necessary bits for loading and saving a multi-core trace bundle from disk.
- Change some size_t to uint64_t for compatibility with 32 bit systems.
Tested by saving a trace session of a program that sleeps 100 times, it was able to produce the following 'dump info' text:
```
(lldb) trace load /tmp/trace3/trace.json (lldb) thread trace dump info Trace technology: intel-pt
thread #1: tid = 4192415
Total number of instructions: 1
Memory usage:
Total approximate memory usage (excluding raw trace): 2.51 KiB
Average memory usage per instruction (excluding raw trace): 2573.00 bytes
Timing for this thread:
Timing for global tasks:
Context switch trace decoding: 0.00s
Events:
Number of instructions with events: 0
Number of individual events: 0
Multi-core decoding:
Total number of continuous executions found: 2499
Number of continuous executions for this thread: 102
Errors:
Number of TSC decoding errors: 0
```
Differential Revision: https://reviews.llvm.org/D126267
The `frame variable` command supports an implicit `this`/`self`, allowing a
user to run `v some_field` instead of `v this->some_field`. However, some
languages have non-pointer `this`/`self` types (for example, Swift).
This change adds support for non-pointer implicit `this`/`self`. This is done
by consulting the type of the instance variable. If the type is known to be
non-pointer, the dot operator is used instead of the arrow operator.
The C language of families each have a pointer instance type, which makes
testing of this difficult. Tests for this feature will be done in the Swift
downstream fork, as Swift's `self` is a non-pointer (reference) type.
rdar://82095148
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D127605
:q!
This diff is massive, but it's because it connects the client with lldb-server
and also ensures that the postmortem case works.
- Flatten the postmortem trace schema. The reason is that the schema has become quite complex due to the new multicore case, which defeats the original purpose of having a schema that could work for every trace plug-in. At this point, it's better that each trace plug-in defines it's own full schema. This means that the only common field is "type".
-- Because of this new approach, I merged the "common" trace load and saving functionalities into the IntelPT one. This simplified the code quite a bit. If we eventually implement another trace plug-in, we can see then what we could reuse.
-- The new schema, which is flattened, has now better comments and is parsed better. A change I did was to disallow hex addresses, because they are a bit error prone. I'm asking now to print the address in decimal.
-- Renamed "intel" to "GenuineIntel" in the schema because that's what you see in /proc/cpuinfo.
- Implemented reading the context switch trace data buffer. I had to do
some refactors to do that cleanly.
-- A major change that I did here was to simplify the perf_event circular buffer reading logic. It was too complex. Maybe the original Intel author had something different in mind.
- Implemented all the necessary bits to read trace.json files with per-core data.
- Implemented all the necessary bits to save to disk per-core trace session.
- Added a test that ensures that parsing and saving to disk works.
Differential Revision: https://reviews.llvm.org/D126015
- Add logging for when the live state of the process is refreshed
- Move error handling of the live state refreshing to Trace from TraceIntelPT. This allows refreshing to fail either at the plug-in level or at the base class level. The error is cached and it can be gotten every time RefreshLiveProcessState is invoked.
- Allow DoRefreshLiveProcessState to handle plugin-specific parameters.
- Add some encapsulation to prevent TraceIntelPT from accessing variables belonging to Trace.
Test done via logging:
```
(lldb) b main
Breakpoint 1: where = a.out`main + 20 at main.cpp:27:20, address = 0x00000000004023d9
(lldb) r
Process 2359706 launched: '/home/wallace/a.out' (x86_64)
Process 2359706 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x00000000004023d9 a.out`main at main.cpp:27:20
24 };
25
26 int main() {
-> 27 std::vector<int> vvv;
28 for (int i = 0; i < 100000; i++)
29 vvv.push_back(i);
30
(lldb) process trace start (lldb) log enable lldb target -F(lldb) n
Process 2359706 stopped
* thread #1, name = 'a.out', stop reason = step over
frame #0: 0x00000000004023e8 a.out`main at main.cpp:28:12
25
26 int main() {
27 std::vector<int> vvv;
-> 28 for (int i = 0; i < 100000; i++)
29 vvv.push_back(i);
30
31 std::deque<int> dq1 = {1, 2, 3};
(lldb) thread trace dump instructions -c 2 -t Trace.cpp:RefreshLiveProcessState Trace::RefreshLiveProcessState invoked
TraceIntelPT.cpp:DoRefreshLiveProcessState TraceIntelPT found tsc conversion information
thread #1: tid = 2359706
a.out`std::vector<int, std::allocator<int>>::vector() + 26 at stl_vector.h:395:19
54: [tsc=unavailable] 0x0000000000403a7c retq
```
See the logging lines at the end of the dump. They indicate that refreshing happened and that perf conversion information was found.
Differential Revision: https://reviews.llvm.org/D125943
lldb will only backtrace a fixed number of stack frames, as a
last-ditch attempt to avoid a runaway looping backtrace. It's
unusual that anyone ends up depending on this final safety net in
years. I picked the original number of 300000 was picked by seeing
how many stack frames I could make in a small recursive function
on Darwin systems before using the default stack space. Checking
again today on a modern system, I can exceed this limit & lldb will
not show the original invocation of the recursing call. Double the
old value to cover this larger maximum possible stack frame count,
as a default value.
(`target.process.thread.max-backtrace-depth`)
so that they can be used to prime new Process runs. "process handle"
was also changed to populate the dummy target if there's no selected
target, so that the settings will get copied into new targets.
Differential Revision: https://reviews.llvm.org/D126259
should not receive as exceptions (some will get converted to BSD
signals instead). This is really the only stable way to ensure that
a Mach exception gets converted to it's equivalent BSD signal. For
programs that rely on BSD signal handlers, this has to happen or you
can't even get the program to invoke the signal handler when under
the debugger.
This builds on a previous solution to this problem which required you
start debugserver with the -U flag. This was not very discoverable
and required lldb be the one to launch debugserver, which is not always
the case.
Differential Revision: https://reviews.llvm.org/D125434
Non-address bits are not part of the virtual address in a pointer.
So they must be removed before passing to interfaces like ptrace.
Some of them we get way with not removing, like AArch64's top byte.
However this is only because of a hardware feature that ignores them.
This change updates all the Process/Target Read/Write memory methods
to remove non-address bits before using addresses.
Doing it in this way keeps lldb-server simple and also fixes the
memory caching when differently tagged pointers for the same location
are read.
Removing the bits is done at the ReadMemory level not DoReadMemory
because particualrly for process, many subclasses override DoReadMemory.
Tests have been added for read/write at the command and API level,
for process and target. This includes variants like
Read<sometype>FromMemory. Commands are tested to make sure we remove
at the command and API level.
"memory find" is not included because:
* There is no API for it.
* It already has its own address handling tests.
Software breakpoints do use these methods but they are not tested
here because there are bigger issues to fix with those. This will
happen in another change.
Reviewed By: omjavaid
Differential Revision: https://reviews.llvm.org/D118794
This diffs implements per-core tracing on lldb-server. It also includes tests that ensure that tracing can be initiated from the client and that the jLLDBGetState ppacket returns the list of trace buffers per core.
This doesn't include any decoder changes.
Finally, this makes some little changes here and there improving the existing code.
A specific piece of code that can't reliably be tested is when tracing
per core fails due to permissions. In this case we add a
troubleshooting message and this is the manual test:
```
/proc/sys/kernel/perf_event_paranoid set to 1
(lldb) process trace start --per-core-tracing error: perf event syscall failed: Permission denied
You might need that /proc/sys/kernel/perf_event_paranoid has a value of 0 or -1.
``
Differential Revision: https://reviews.llvm.org/D124858
llvm's json parser supports uint64_t, so let's better use it for the
packets being sent between lldb and lldb-server instead of using int64_t
as an intermediate type, which might be error-prone.
symbol name matches. Instead, we extract the incoming path's base
name, look up all the symbols with that base name, and then compare
the rest of the context that the user provided to make sure it
matches. However, we do this comparison using just a strstr. So for
instance:
break set -n foo::bar
will match not only "a::foo::bar" but "notherfoo::bar". The former is
pretty clearly the user's intent, but I don't think the latter is, and
results in breakpoints picking up too many matches.
This change adds a Language::DemangledNameContainsPath API which can
do a language aware match against the path provided. If the language
doesn't provide this we fall back to the strstr (though that's changed
to StringRef::contains in the patch).
Differential Revision: https://reviews.llvm.org/D124579
llvm's json parser supports uint64_t, so let's better use it for the
packets being sent between lldb and lldb-server instead of using int64_t
as an intermediate type, which might be error-prone.
