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
https://reviews.llvm.org/D128453 recently added some safety checks for
command arguments. Unfortunately, some few commands started failing due
to that, and this diff fixes it. But fortunately, the fix is trivial, which is
simply declaring the argument that these commands will receive.
Differential Revision: https://reviews.llvm.org/D128775
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
The requirements for "thread until <line number>" are:
a) If any code contributed by <line number> or the nearest subsequent of <line number> is executed before leaving the function, stop
b) If you end up leaving the function w/o triggering (a), then stop
In case of (a), since the <line number> may have multiple entries in the line table and the compiler might have scheduled/moved the relevant code across, and the lldb does not know the control flow, set breakpoints on all the line table entries of best match of <line number> i.e. exact or the nearest subsequent line.
Along with the above, currently, CommandObjectThreadUntil is also setting the breakpoints on all the subsequent line numbers after the best match and this latter part is wrong.
This issue is discussed at http://lists.llvm.org/pipermail/lldb-dev/2018-August/013979.html.
In fact, currently `TestStepUntil.py` is not actually testing step until scenarios and `test_missing_one` test fails without this patch if tests are made to run. Fixed the test as well.
Reviewed By: jingham
Differential Revision: https://reviews.llvm.org/D50304
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
For the 'thread until' command, the selected thread ID, to perform the operation on, could be of the current thread or the specified thread.
Reviewed By: jingham
Differential Revision: https://reviews.llvm.org/D48865
A trace might contain events traced during the target's execution. For
example, a thread might be paused for some period of time due to context
switches or breakpoints, which actually force a context switch. Not only
that, a trace might be paused because the CPU decides to trace only a
specific part of the target, like the address filtering provided by
intel pt, which will cause pause events. Besides this case, other kinds
of events might exist.
This patch adds the method `TraceCursor::GetEvents()`` that returns the
list of events that happened right before the instruction being pointed
at by the cursor. Some refactors were done to make this change simpler.
Besides this new API, the instruction dumper now supports the -e flag
which shows pause events, like in the following example, where pauses
happened due to breakpoints.
```
thread #1: tid = 2717361
a.out`main + 20 at main.cpp:27:20
0: 0x00000000004023d9 leaq -0x1200(%rbp), %rax
[paused]
1: 0x00000000004023e0 movq %rax, %rdi
[paused]
2: 0x00000000004023e3 callq 0x403a62 ; std::vector<int, std::allocator<int> >::vector at stl_vector.h:391:7
a.out`std::vector<int, std::allocator<int> >::vector() at stl_vector.h:391:7
3: 0x0000000000403a62 pushq %rbp
4: 0x0000000000403a63 movq %rsp, %rbp
```
The `dump info` command has also been updated and now it shows the
number of instructions that have associated events.
Differential Revision: https://reviews.llvm.org/D123982
In order to support quick arbitrary access to instructions in the trace, we need
each instruction to have an id. It could be an index or any other value that the
trace plugin defines.
This will be useful for reverse debugging or for creating callstacks, as each
frame will need an instruction id associated with them.
I've updated the `thread trace dump instructions` command accordingly. It now
prints the instruction id instead of relative offset. I've also added a new --id
argument that allows starting the dump from an arbitrary position.
Differential Revision: https://reviews.llvm.org/D122254
Minor fixes needed and now `./bin/lldb-dotest -p TestTrace` passes
correctly.
- There was an incorrect iteration.
- Some error messages changed.
- The way repeat commands are handled changed a bit, so I had to create
a new --continue arg in "thread trace dump instructions" to handle this
correctly.
Differential Revision: https://reviews.llvm.org/D122023
Applied modernize-use-default-member-init clang-tidy check over LLDB.
It appears in many files we had already switched to in class member init but
never updated the constructors to reflect that. This check is already present in
the lldb/.clang-tidy config.
Differential Revision: https://reviews.llvm.org/D121481
Some dyld cross library stubs can have line information but no function. Make sure you
check that you have a valid Function object before asking it questions.
Differential Revision: https://reviews.llvm.org/D119297
This way if you have a long stack, you can issue "thread backtrace --count 10"
and then subsequent <Return>-s will page you through the stack.
This took a little more effort than just adding the repeat command, since
the GetRepeatCommand API was returning a "const char *". That meant the command
had to keep the repeat string alive, which is inconvenient. The original
API returned either a nullptr, or a const char *, so I changed the private API to
return an llvm::Optional<std::string>. Most of the patch is propagating that change.
Also, there was a little thinko in fetching the repeat command. We don't
fetch repeat commands for commands that aren't being added to history, which
is in general reasonable. And we don't add repeat commands to the history -
also reasonable. But we do want the repeat command to be able to generate
the NEXT repeat command. So I adjusted the logic in HandleCommand to work
that way.
Differential Revision: https://reviews.llvm.org/D119046
[NFC] As part of using inclusive language within the llvm project, this patch
renames master plan to controlling plan in lldb.
Reviewed By: jingham
Differential Revision: https://reviews.llvm.org/D113019
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
We added some support for this mode back in 2015, but the feature was
never productionized. It is completely untested, and there are known
major structural lldb issues that need to be resolved before this
feature can really be supported.
It also complicates making further changes to stop reply packet
handling, which is what I am about to do.
Differential Revision: https://reviews.llvm.org/D110553
Copying from the inline documentation:
```
Trace exporter plug-ins operate on traces, converting the trace data provided by an \a lldb_private::TraceCursor into a different format that can be digested by other tools, e.g. Chrome Trace Event Profiler.
Trace exporters are supposed to operate on an architecture-agnostic fashion, as a TraceCursor, which feeds the data, hides the actual trace technology being used.
```
I want to use this to make the code in https://reviews.llvm.org/D105741 a plug-in. I also imagine that there will be more and more exporters being implemented, as an exporter creates something useful out of trace data. And tbh I don't want to keep adding more stuff to the lldb/Target folder.
This is the minimal definition for a TraceExporter plugin. I plan to use this with the following commands:
- thread trace export <plug-in name> [plug-in specific args]
- This command would support autocompletion of plug-in names
- thread trace export list
- This command would list the available trace exporter plug-ins
I don't plan to create yet a "process trace export" because it's easier to start analyzing the trace of a given thread than of the entire process. When we need a process-level command, we can implement it.
I also don't plan to force each "export" command implementation to support multiple threads (for example, "thread trace start 1 2 3" or "thread trace start all" operate on many threads simultaneously). The reason is that the format used by the exporter might or might not support multiple threads, so I'm leaving this decision to each trace exporter plug-in.
Differential Revision: https://reviews.llvm.org/D106501
When the user types that command 'thread trace dump info' and there's a running Trace session in LLDB, a raw trace in bytes should be printed; the command 'thread trace dump info all' should print the info for all the threads.
Original Author: hanbingwang
Reviewed By: clayborg, wallace
Differential Revision: https://reviews.llvm.org/D105717
D104422 added the interface for TraceCursor, which is the main way to traverse instructions in a trace. This diff implements the corresponding cursor class for Intel PT and deletes the now obsolete code.
Besides that, the logic for the "thread trace dump instructions" was adapted to use this cursor (pretty much I ended up moving code from Trace.cpp to TraceCursor.cpp). The command by default traverses the instructions backwards, and if the user passes --forwards, then it's not forwards. More information about that is in the Options.td file.
Regarding the Intel PT cursor. All Intel PT cursors for the same thread share the same DecodedThread instance. I'm not yet implementing lazy decoding because we don't need it. That'll be for later. For the time being, the entire thread trace is decoded when the first cursor for that thread is requested.
Differential Revision: https://reviews.llvm.org/D105531
Replacing existing uses with AppendError.
SetError is also part of the SBI API. This remains
but instead of calling the underlying SetError it
will call AppendError.
Reviewed By: teemperor
Differential Revision: https://reviews.llvm.org/D104768
This adds a basic SB API for creating and stopping traces.
Note: This doesn't add any APIs for inspecting individual instructions. That'd be a more complicated change and it might be better to enhande the dump functionality to output the data in binary format. I'll leave that for a later diff.
This also enhances the existing tests so that they test the same flow using both the command interface and the SB API.
I also did some cleanup of legacy code.
Differential Revision: https://reviews.llvm.org/D103500
This is part 2, covering the commands source.
Some uses remain where it's tricky to see what the
logic is or they are not used with AppendError.
Reviewed By: teemperor
Differential Revision: https://reviews.llvm.org/D104448
This converts a default constructor's member initializers into C++11
default member initializers. This patch was automatically generated with
clang-tidy and the modernize-use-default-member-init check.
$ run-clang-tidy.py -header-filter='lldb' -checks='-*,modernize-use-default-member-init' -fix
This is a mass-refactoring patch and this commit will be added to
.git-blame-ignore-revs.
Differential revision: https://reviews.llvm.org/D103483
This implements the interactive trace start and stop methods.
This diff ended up being much larger than I anticipated because, by doing it, I found that I had implemented in the beginning many things in a non optimal way. In any case, the code is much better now.
There's a lot of boilerplate code due to the gdb-remote protocol, but the main changes are:
- New tracing packets: jLLDBTraceStop, jLLDBTraceStart, jLLDBTraceGetBinaryData. The gdb-remote packet definitions are quite comprehensive.
- Implementation of the "process trace start|stop" and "thread trace start|stop" commands.
- Implementaiton of an API in Trace.h to interact with live traces.
- Created an IntelPTDecoder for live threads, that use the debugger's stop id as checkpoint for its internal cache.
- Added a functionality to stop the process in case "process tracing" is enabled and a new thread can't traced.
- Added tests
I have some ideas to unify the code paths for post mortem and live threads, but I'll do that in another diff.
Differential Revision: https://reviews.llvm.org/D91679
Depends on D90490.
The stop command is simple and invokes the new method Trace::StopTracingThread(thread).
On the other hand, the start command works by delegating its implementation to a CommandObject provided by the Trace plugin. This is necessary because each trace plugin needs different options for this command. There's even the chance that a Trace plugin can't support live tracing, but instead supports offline decoding and analysis, which means that "thread trace dump instructions" works but "thread trace start" doest. Because of this and a few other reasons, it's better to have each plugin provide this implementation.
Besides, I'm using the GetSupportedTraceType method introduced in D90490 to quickly infer what's the trace plug-in that works for the current process.
As an implementation note, I moved CommandObjectIterateOverThreads to its header so that I can use it from the IntelPT plugin. Besides, the actual start and stop logic for intel-pt is not part of this diff.
Reviewed By: clayborg
Differential Revision: https://reviews.llvm.org/D90729
Depends on D89408.
This diff finally implements trace decoding!
The current interface is
$ trace load /path/to/trace/session/file.json
$ thread trace dump instructions
thread #1: tid = 3842849, total instructions = 22
[ 0] 0x40052d
[ 1] 0x40052d
...
[19] 0x400521
$ # simply enter, which is a repeat command
[20] 0x40052d
[21] 0x400529
...
This doesn't do any disassembly, which will be done in the next diff.
Changes:
- Added an IntelPTDecoder class, that is a wrapper for libipt, which is the actual library that performs the decoding.
- Added TraceThreadDecoder class that decodes traces and memoizes the result to avoid repeating the decoding step.
- Added a DecodedThread class, which represents the output from decoding and that for the time being only stores the list of reconstructed instructions. Later it'll contain the function call hierarchy, which will enable reconstructing backtraces.
- Added basic APIs for accessing the trace in Trace.h:
- GetInstructionCount, which counts the number of instructions traced for a given thread
- IsTraceFailed, which returns an Error if decoding a thread failed
- ForEachInstruction, which iterates on the instructions traced for a given thread, concealing the internal storage of threads, as plug-ins can decide to generate the instructions on the fly or to store them all in a vector, like I do.
- DumpTraceInstructions was updated to print the instructions or show an error message if decoding was impossible.
- Tests included
Differential Revision: https://reviews.llvm.org/D89283
Depends on D88841
As per the discussion in the RFC, we'll implement both
thread trace dump [instructions | functions]
This is the first step in implementing the "instructions" dumping command.
It includes:
- A minimal ProcessTrace plugin for representing processes from a trace file. I noticed that it was a required step to mimic how core-based processes are initialized, e.g. ProcessElfCore and ProcessMinidump. I haven't had the need to create ThreadTrace yet, though. So far HistoryThread seems good enough.
- The command handling itself in CommandObjectThread, which outputs a placeholder text instead of the actual instructions. I'll do that part in the next diff.
- Tests
{F13132325}
Differential Revision: https://reviews.llvm.org/D88769
1. Added a common completion completing with a list of the threads of the current process;
2. Apply the common completion above to these commands: thread
continue/info/exception/select/step-in/step-inst/step-inst-over/step-out/step-over/step-script
3. Correlated test case test_common_completion_thread_index.
Reviewed By: teemperor
Differential Revision: https://reviews.llvm.org/D84088
Dedicated completion for the command `thread plan discard` with a corresponding
test case.
Reviewed By: teemperor
Differential Revision: https://reviews.llvm.org/D83234
Summary:
This replaces the current use of LLDB's own `StringConvert` with LLVM's
`to_integer` which has a less error-prone API and doesn't use special 'error
values' to designate parsing problems.
Where needed I also added missing error handling code that prints a parsing
error instead of continuing with the error value returned from `StringConvert`
(which either gave a cryptic error message or just took the error value
performed an incorrect action with it. For example, `frame recognizer delete -1`
just deleted the frame recognizer at index 0).
Reviewers: #lldb, labath
Reviewed By: labath
Subscribers: labath, abidh, JDevlieghere
Differential Revision: https://reviews.llvm.org/D82297
that were not reported by the OS plugin. To facilitate this, move
adding/updating the ThreadPlans for a Thread to the ThreadPlanStackMap.
Also move dumping thread plans there as well.
Added some tests for "thread plan list" and "thread plan discard" since
I didn't seem to have written any originally.
Differential Revision: https://reviews.llvm.org/D76814
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.
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
Summary: This removes most of unnecessary includes in the `source/Commands` directory. This was generated by IWYU and a script that fixed all the bogus reports from IWYU. Patch is tested on Linux and macOS.
Reviewers: JDevlieghere
Reviewed By: JDevlieghere
Subscribers: krytarowski, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D71489
Summary:
CompileUnit is a complicated class. Having it be implicitly convertible
to a FileSpec makes reasoning about it even harder.
This patch replaces the inheritance by a simple member and an accessor
function. This avoid the need for casting in places where one needed to
force a CompileUnit to be treated as a FileSpec, and does not add much
verbosity elsewhere.
It also fixes a bug where we were wrongly comparing CompileUnit& and a
CompileUnit*, which compiled due to a combination of this inheritance
and the FileSpec*->FileSpec implicit constructor.
Reviewers: teemperor, JDevlieghere, jdoerfert
Subscribers: lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70827
For example, it is pretty easy to write a breakpoint command that implements "stop when my caller is Foo", and
it is pretty easy to write a breakpoint command that implements "stop when my caller is Bar". But there's no
way to write a generic "stop when my caller is..." function, and then specify the caller when you add the
command to a breakpoint.
With this patch, you can pass this data in a SBStructuredData dictionary. That will get stored in
the PythonCommandBaton for the breakpoint, and passed to the implementation function (if it has the right
signature) when the breakpoint is hit. Then in lldb, you can say:
(lldb) break com add -F caller_is -k caller_name -v Foo
More generally this will allow us to write reusable Python breakpoint commands.
Differential Revision: https://reviews.llvm.org/D68671
This will allow us to write reusable scripted ThreadPlans, since
you can use key/value pairs with known keys in the plan to parametrize
its behavior.
Differential Revision: https://reviews.llvm.org/D68366
llvm-svn: 373675
The StringRef should always be identical to the C string, so we
might as well just create the StringRef from the C-string. This
might be slightly slower until we implement the storage of ArgEntry
with a string instead of a std::unique_ptr<char[]>. Until then we
have to do the additional strlen on the C string to construct the
StringRef.
llvm-svn: 371842
