[lldb] Fix Intel PT plugin compile errors (#77252)

Fix #77251.

[lldb][NFCI] DecodedThread::TraceItemStorage::error should own its own data

The way it works now, it stores a `const char *` that it does not
explicitly own. It's owned by the ConstString StringPool

[lldb][NFCI] DecodedThread::TraceItemStorage::error should own its own data

The way it works now, it stores a `const char *` that it does not
explicitly own. It's owned by the ConstString StringPool. This is purely
to manage its lifetime, we don't really benefit from deduplication (nor
should we try to, they are errors). We also don't really benefit from
quick comparisons.

This may make the size of TraceItemStorage larger, but you have to pay
the cost of owning the data somewhere. The ConstString StringPool is an
attractive choice but ultimately a poor one.

Differential Revision: https://reviews.llvm.org/D152326

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[lldb] Use std::optional instead of llvm::Optional (NFC)

This patch replaces (llvm::|)Optional< with std::optional<. I'll post
a separate patch to clean up the "using" declarations, #include
"llvm/

[lldb] Use std::optional instead of llvm::Optional (NFC)

This patch replaces (llvm::|)Optional< with std::optional<. I'll post
a separate patch to clean up the "using" declarations, #include
"llvm/ADT/Optional.h", etc.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

show more ...

[lldb] Add #include <optional> (NFC)

This patch adds #include <optional> to those files containing
llvm::Optional<...> or Optional<...>.

I'll post a separate patch to actually replace llvm::Optiona

[lldb] Add #include <optional> (NFC)

This patch adds #include <optional> to those files containing
llvm::Optional<...> or Optional<...>.

I'll post a separate patch to actually replace llvm::Optional with
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

show more ...

[lldb] Use std::nullopt instead of llvm::None (NFC)

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getv

[lldb] Use std::nullopt instead of llvm::None (NFC)

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

show more ...

[trace][intel pt] Simple detection of infinite decoding loops

The low-level decoder might fall into an infinite decoding loop for
various reasons, the simplest being an infinite direct loop reached

[trace][intel pt] Simple detection of infinite decoding loops

The low-level decoder might fall into an infinite decoding loop for
various reasons, the simplest being an infinite direct loop reached due
to wrong handling of self-modified code in the kernel, e.g. it might
reach

```
0x0A: pause
0x0C: jump to 0x0A
```

In this case, all the code is sequential and requires no packets to be
decoded. The low-level decoder would produce an output like the
following

```
0x0A: pause
0x0C: jump to 0x0A
0x0A: pause
0x0C: jump to 0x0A
0x0A: pause
0x0C: jump to 0x0A
... infinite amount of times
```

These cases require stopping the decoder to avoid infinite work and signal this
at least as a trace error.

- Add a check that breaks decoding of a single PSB once 500k instructions have been decoded since the last packet was processed.
- Add a check that looks for infinite loops after certain amount of instructions have been decoded since the last packet was processed.
- Add some `settings` properties for tweaking the thresholds of the checks above. This is also nice because it does the basic work needed for future settings.
- Add an AnomalyDetector class that inspects the DecodedThread and the libipt decoder in search for anomalies. These anomalies are then signaled as fatal errors in the trace.
- Add an ErrorStats class that keeps track of all the errors in a DecodedThread, with a special counter for fatal errors.
- Add an entry for decoded thread errors in the `dump info` command.

Some notes are added in the code and in the documention of the settings,
so please read them.

Besides that, I haven't been unable to create a test case in LLVM style, but
I've found an anomaly in the thread #12 of the trace
72533820-3eb8-4465-b8e4-4e6bf0ccca99 at Meta. We have to figure out how to
artificially create traces with this kind of anomalies in LLVM style.

With this change, that anomalous thread now shows:

```
(lldb)thread trace dump instructions 12 -e -i 23101

thread #12: tid = 8
...missing instructions
23101: (error) anomalous trace: possible infinite loop detected of size 2
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 5 [inlined] rep_nop at processor.h:13:2
23100: 0xffffffff81342785 pause
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 7 at panic.c:87:2
23099: 0xffffffff81342787 jmp 0xffffffff81342785 ; <+5> [inlined] rep_nop at processor.h:13:2
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 5 [inlined] rep_nop at processor.h:13:2
23098: 0xffffffff81342785 pause
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 7 at panic.c:87:2
23097: 0xffffffff81342787 jmp 0xffffffff81342785 ; <+5> [inlined] rep_nop at processor.h:13:2
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 5 [inlined] rep_nop at processor.h:13:2
23096: 0xffffffff81342785 pause
vmlinux-5.12.0-0_fbk8_clang_6656_gc85768aa64da`panic_smp_self_stop + 7 at panic.c:87:2
23095: 0xffffffff81342787 jmp 0xffffffff81342785 ; <+5> [inlined] rep_nop at processor.h:13:2
```

It used to be in an infinite loop where the decoder never stopped.

Besides that, the dump info command shows

```
(lldb) thread trace dump info 12

Errors:
Number of individual errors: 32
Number of fatal errors: 1
Number of other errors: 31
```

and in json format

```
(lldb) thread trace dump info 12 -j

"errors": {
"totalCount": 32,
"libiptErrors": {},
"fatalErrors": 1,
"otherErrors": 31
}
```

Differential Revision: https://reviews.llvm.org/D136557

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[trace][intel pt] Fix per-psb packet decoding

The per-PSB packet decoding logic was wrong because it was assuming that pt_insn_get_sync_offset was being udpated after every PSB. Silly me, that is no

[trace][intel pt] Fix per-psb packet decoding

The per-PSB packet decoding logic was wrong because it was assuming that pt_insn_get_sync_offset was being udpated after every PSB. Silly me, that is not true. It returns the offset of the PSB packet after invoking pt_insn_sync_forward regardless of how many PSBs are visited later. Instead, I'm now following the approach described in https://github.com/intel/libipt/blob/master/doc/howto_libipt.md#parallel-decode for parallel decoding, which is basically what we need.

A nasty error that happened because of this is that when we had two PSBs (A and B), the following was happening

1. PSB A was processed all the way up to the end of the trace, which includes PSB B.
2. PSB B was then processed until the end of the trace.

The instructions emitted by step 2. were also emitted as part of step 1. so our trace had duplicated chunks. This problem becomes worse when you many PSBs.

As part of making sure this diff is correct, I added some other features that are very useful.

- Added a "synchronization point" event to the TraceCursor, so we can inspect when PSBs are emitted.
- Removed the single-thread decoder. Now the per-cpu decoder and single-thread decoder use the same code paths.
- Use the query decoder to fetch PSBs and timestamps. It turns out that the pt_insn_sync_forward of the instruction decoder can move past several PSBs (this means that we could skip some TSCs). On the other hand, the pt_query_sync_forward method doesn't skip PSBs, so we can get more accurate sync events and timing information.
- Turned LibiptDecoder into PSBBlockDecoder, which decodes single PSB blocks. It is the fundamental processing unit for decoding.
- Added many comments, asserts and improved error handling for clarity.
- Improved DecodeSystemWideTraceForThread so that a TSC is emitted always before a cpu change event. This was a bug that was annoying me before.
- SplitTraceInContinuousExecutions and FindLowestTSCInTrace are now using the query decoder, which can identify precisely each PSB along with their TSCs.
- Added an "only-events" option to the trace dumper to inspect only events.

I did extensive testing and I think we should have an in-house testing CI. The LLVM buildbots are not capable of supporting testing post-mortem traces of hundreds of megabytes. I'll leave that for later, but at least for now the current tests were able to catch most of the issues I encountered when doing this task.

A sample output of a program that I was single stepping is the following. You can see that only one PSB is emitted even though stepping happened!

```
thread #1: tid = 3578223
0: (event) trace synchronization point [offset = 0x0xef0]
a.out`main + 20 at main.cpp:29:20
1: 0x0000000000402479 leaq -0x1210(%rbp), %rax
2: (event) software disabled tracing
3: 0x0000000000402480 movq %rax, %rdi
4: (event) software disabled tracing
5: (event) software disabled tracing
6: 0x0000000000402483 callq 0x403bd4 ; std::vector<int, std::allocator<int>>::vector at stl_vector.h:391:7
7: (event) software disabled tracing
a.out`std::vector<int, std::allocator<int>>::vector() at stl_vector.h:391:7
8: 0x0000000000403bd4 pushq %rbp
9: (event) software disabled tracing
10: 0x0000000000403bd5 movq %rsp, %rbp
11: (event) software disabled tracing
```

This is another trace of a long program with a few PSBs.
```
(lldb) thread trace dump instructions -E -f thread #1: tid = 3603082
0: (event) trace synchronization point [offset = 0x0x80]
47417: (event) software disabled tracing
129231: (event) trace synchronization point [offset = 0x0x800]
146747: (event) software disabled tracing
246076: (event) software disabled tracing
259068: (event) trace synchronization point [offset = 0x0xf78]
259276: (event) software disabled tracing
259278: (event) software disabled tracing
no more data
```

Differential Revision: https://reviews.llvm.org/D131630

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[NFC][lldb][trace] Fix formatting of tracing files

Pavel Labath taught me that clang-format sorts headers automatically
using llvm's rules, and it's better not to have spaces between

So in this dif

[NFC][lldb][trace] Fix formatting of tracing files

Pavel Labath taught me that clang-format sorts headers automatically
using llvm's rules, and it's better not to have spaces between

So in this diff I'm removing those spaces and formatting them as well.

I used `clang-format -i` to format these files.

show more ...

[trace] Add SBTraceCursor bindings

Add bindings for the `TraceCursor` to allow for programatic traversal of
traces.
This diff adds bindings for all public `TraceCursor` methods except
`GetHwClock` a

[trace] Add SBTraceCursor bindings

Add bindings for the `TraceCursor` to allow for programatic traversal of
traces.
This diff adds bindings for all public `TraceCursor` methods except
`GetHwClock` and also adds `SBTrace::CreateNewCursor`. A new unittest
has been added to TestTraceLoad.py that uses the new `SBTraceCursor` API
to test that the sequential and random access APIs of the `TraceCursor`
are equivalent.

This diff depends on D130925.

Test Plan:
`ninja lldb-dotest && ./bin/lldb-dotest -p TestTraceLoad`

Differential Revision: https://reviews.llvm.org/D130930

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[trace][intel pt] Introduce wall clock time for each trace item

- Decouple TSCs from trace items
- Turn TSCs into events just like CPUs. The new name is HW clock tick, wich could be reused by other

[trace][intel pt] Introduce wall clock time for each trace item

- Decouple TSCs from trace items
- Turn TSCs into events just like CPUs. The new name is HW clock tick, wich could be reused by other vendors.
- Add a GetWallTime that returns the wall time that the trace plug-in can infer for each trace item.
- For intel pt, we are doing the following interpolation: if an instruction takes less than 1 TSC, we use that duration, otherwise, we assume the instruction took 1 TSC. This helps us avoid having to handle context switches, changes to kernel, idle times, decoding errors, etc. We are just trying to show some approximation and not the real data. For the real data, TSCs are the way to go. Besides that, we are making sure that no two trace items will give the same interpolation value. Finally, we are using as time 0 the time at which tracing started.

Sample output:

```
(lldb) r
Process 750047 launched: '/home/wallace/a.out' (x86_64)
Process 750047 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x0000000000402479 a.out`main at main.cpp:29:20
26 };
27
28 int main() {
-> 29 std::vector<int> vvv;
30 for (int i = 0; i < 100; i++)
31 vvv.push_back(i);
32
(lldb) process trace start -s 64kb -t --per-cpu
(lldb) b 60
Breakpoint 2: where = a.out`main + 1689 at main.cpp:60:23, address = 0x0000000000402afe
(lldb) c
Process 750047 resuming
Process 750047 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 2.1
frame #0: 0x0000000000402afe a.out`main at main.cpp:60:23
57 map<int, int> m;
58 m[3] = 4;
59
-> 60 map<string, string> m2;
61 m2["5"] = "6";
62
63 std::vector<std::string> vs = {"2", "3"};
(lldb) thread trace dump instructions -t -f -e thread #1: tid = 750047
0: [379567.000 ns] (event) HW clock tick [48599428476224707]
1: [379569.000 ns] (event) CPU core changed [new CPU=2]
2: [390487.000 ns] (event) HW clock tick [48599428476246495]
3: [1602508.000 ns] (event) HW clock tick [48599428478664855]
4: [1662745.000 ns] (event) HW clock tick [48599428478785046]
libc.so.6`malloc
5: [1662746.995 ns] 0x00007ffff7176660 endbr64
6: [1662748.991 ns] 0x00007ffff7176664 movq 0x32387d(%rip), %rax ; + 408
7: [1662750.986 ns] 0x00007ffff717666b pushq %r12
8: [1662752.981 ns] 0x00007ffff717666d pushq %rbp
9: [1662754.977 ns] 0x00007ffff717666e pushq %rbx
10: [1662756.972 ns] 0x00007ffff717666f movq (%rax), %rax
11: [1662758.967 ns] 0x00007ffff7176672 testq %rax, %rax
12: [1662760.963 ns] 0x00007ffff7176675 jne 0x9c7e0 ; <+384>
13: [1662762.958 ns] 0x00007ffff717667b leaq 0x17(%rdi), %rax
14: [1662764.953 ns] 0x00007ffff717667f cmpq $0x1f, %rax
15: [1662766.949 ns] 0x00007ffff7176683 ja 0x9c730 ; <+208>
16: [1662768.944 ns] 0x00007ffff7176730 andq $-0x10, %rax
17: [1662770.939 ns] 0x00007ffff7176734 cmpq $-0x41, %rax
18: [1662772.935 ns] 0x00007ffff7176738 seta %dl
19: [1662774.930 ns] 0x00007ffff717673b jmp 0x9c690 ; <+48>
20: [1662776.925 ns] 0x00007ffff7176690 cmpq %rdi, %rax
21: [1662778.921 ns] 0x00007ffff7176693 jb 0x9c7b0 ; <+336>
22: [1662780.916 ns] 0x00007ffff7176699 testb %dl, %dl
23: [1662782.911 ns] 0x00007ffff717669b jne 0x9c7b0 ; <+336>
24: [1662784.906 ns] 0x00007ffff71766a1 movq 0x3236c0(%rip), %r12 ; + 24
(lldb) thread trace dump instructions -t -f -e -J -c 4
[
{
"id": 0,
"timestamp_ns": "379567.000000",
"event": "HW clock tick",
"hwClock": 48599428476224707
},
{
"id": 1,
"timestamp_ns": "379569.000000",
"event": "CPU core changed",
"cpuId": 2
},
{
"id": 2,
"timestamp_ns": "390487.000000",
"event": "HW clock tick",
"hwClock": 48599428476246495
},
{
"id": 3,
"timestamp_ns": "1602508.000000",
"event": "HW clock tick",
"hwClock": 48599428478664855
},
{
"id": 4,
"timestamp_ns": "1662745.000000",
"event": "HW clock tick",
"hwClock": 48599428478785046
},
{
"id": 5,
"timestamp_ns": "1662746.995324",
"loadAddress": "0x7ffff7176660",
"module": "libc.so.6",
"symbol": "malloc",
"mnemonic": "endbr64"
},
{
"id": 6,
"timestamp_ns": "1662748.990648",
"loadAddress": "0x7ffff7176664",
"module": "libc.so.6",
"symbol": "malloc",
"mnemonic": "movq"
},
{
"id": 7,
"timestamp_ns": "1662750.985972",
"loadAddress": "0x7ffff717666b",
"module": "libc.so.6",
"symbol": "malloc",
"mnemonic": "pushq"
},
{
"id": 8,
"timestamp_ns": "1662752.981296",
"loadAddress": "0x7ffff717666d",
"module": "libc.so.6",
"symbol": "malloc",
"mnemonic": "pushq"
}
]
```

Differential Revision: https://reviews.llvm.org/D130054

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[trace][intel pt] Create a CPU change event and expose it in the dumper

Thanks to fredzhou@fb.com for coming up with this feature.

When tracing in per-cpu mode, we have information of in which cpu

[trace][intel pt] Create a CPU change event and expose it in the dumper

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

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[trace] Make events first class items in the trace cursor and rework errors

We want to include events with metadata, like context switches, and this
requires the API to handle events with payloads (

[trace] Make events first class items in the trace cursor and rework errors

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

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[trace] Improve the TraceCursor iteration API

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 v

[trace] Improve the TraceCursor iteration API

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

show more ...

[trace][intel pt] Support events

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 breakpoin

[trace][intel pt] Support events

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

show more ...

[trace][intelpt] Remove code smell when printing the raw trace size

Something ugly I did was to report the trace buffer size to the DecodedThread,
which is later used as part of the `dump info` comm

[trace][intelpt] Remove code smell when printing the raw trace size

Something ugly I did was to report the trace buffer size to the DecodedThread,
which is later used as part of the `dump info` command. Instead of doing that,
we can just directly ask the trace for the raw buffer and print its size.

I thought about not asking for the entire trace but instead just for its size,
but in this case, as our traces as not extremely big, I prefer to ask for the
entire trace, ensuring it could be fetched, and then print its size.

Differential Revision: https://reviews.llvm.org/D123358

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[trace][intel pt] Create a class for the libipt decoder wrapper

As we soon will need to decode multiple raw traces for the same thread,
having a class that encapsulates the decoding of a single raw

[trace][intel pt] Create a class for the libipt decoder wrapper

As we soon will need to decode multiple raw traces for the same thread,
having a class that encapsulates the decoding of a single raw trace is
a stepping stone that will make the coming features easier to implement.

So, I'm creating a LibiptDecoder class with that purpose. I refactored
the code and it's now much more readable. Besides that, more comments
were added. With this new structure, it's also easier to implement unit
tests.

Differential Revision: https://reviews.llvm.org/D123106

show more ...

[trace][intelpt] Introduce instruction Ids

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 th

[trace][intelpt] Introduce instruction Ids

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

show more ...

[lldb][intelpt] Remove `IntelPTInstruction` and move methods to `DecodedThread`

This is to reduce the size of the trace further and has appreciable results.

Differential Revision: https://reviews.l

[lldb][intelpt] Remove `IntelPTInstruction` and move methods to `DecodedThread`

This is to reduce the size of the trace further and has appreciable results.

Differential Revision: https://reviews.llvm.org/D122991

show more ...

[trace][intel pt] Handle better tsc in the decoder

A problem that I introduced in the decoder is that I was considering TSC decoding
errors as actual instruction errors, which mean that the trace ha

[trace][intel pt] Handle better tsc in the decoder

A problem that I introduced in the decoder is that I was considering TSC decoding
errors as actual instruction errors, which mean that the trace has a gap. This is
wrong because a TSC decoding error doesn't mean that there's a gap in the trace.
Instead, now I'm just counting how many of these errors happened and I'm using
the `dump info` command to check for this number.

Besides that, I refactored the decoder a little bit to make it simpler, more
readable, and to handle TSCs in a cleaner way.

Differential Revision: https://reviews.llvm.org/D122867

show more ...

[intelpt] Refactor timestamps out of `IntelPTInstruction`
Storing timestamps (TSCs) in a more efficient map at the decoded thread level to speed up TSC lookup, as well as reduce the amount of memory

[intelpt] Refactor timestamps out of `IntelPTInstruction`
Storing timestamps (TSCs) in a more efficient map at the decoded thread level to speed up TSC lookup, as well as reduce the amount of memory used by each decoded instruction. Also introduced TSC range which keeps the current timestamp valid for all subsequent instructions until the next timestamp is emitted.

Differential Revision: https://reviews.llvm.org/D122603

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[intelpt] Refactoring instruction decoding for flexibility

Now the decoded thread has Append methods that provide more flexibility
in terms of the underlying data structure that represents the
instr

[intelpt] Refactoring instruction decoding for flexibility

Now the decoded thread has Append methods that provide more flexibility
in terms of the underlying data structure that represents the
instructions. In this case, we are able to represent the sporadic errors
as map and thus reduce the size of each instruction.

Differential Revision: https://reviews.llvm.org/D122293

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[trace][intelpt] Added total memory usage by decoded trace

This fails currently but the basics are there

Differential Revision: https://reviews.llvm.org/D122093

[trace] [intel pt] Create a "thread trace dump stats" command

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 pr

[trace] [intel pt] Create a "thread trace dump stats" command

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

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[intel pt] Add TSC timestamps

Differential Revision: https://reviews.llvm.org/D106328

[trace][intel pt] Implement the Intel PT cursor

D104422 added the interface for TraceCursor, which is the main way to traverse instructions in a trace. This diff implements the corresponding cursor

[trace][intel pt] Implement the Intel PT cursor

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

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