1656 Commits

Author SHA1 Message Date
Simon Pilgrim
93a5a03030 [lldb] Host::ShellExpandArguments - fix error check for valid dictionary
Fix repeated check for a valid JSON parse and actually check the dictionary pointer

Reported here: https://pvs-studio.com/en/blog/posts/cpp/1003/ (N40)
2022-10-25 17:44:04 +01:00
Emmmer
05ae747a53 [LLDB][RISCV] Add RV64C instruction support for EmulateInstructionRISCV
Add:

- RV64C instructions sets.
- corresponding unittests.
- `c.break` code for lldb and lldb-server

Fix:
- wrong decoding of imm in `DecodeSType`

Reviewed By: DavidSpickett

Differential Revision: https://reviews.llvm.org/D136362
2022-10-25 19:12:45 +08:00
Michał Górny
e8ee0f121d [lldb] [MainLoopPosix] Fix crash upon adding lots of pending callbacks
If lots of pending callbacks are added while the main loop has exited
already, the trigger pipe buffer fills in, causing the write to fail
and the related assertion to fail.  To avoid this, add a boolean member
indicating whether the callbacks have been triggered already.
If the trigger was done, avoid writing to the pipe until loops proceeds
to run them and resets the variable.

Besides fixing the issue, this also avoids writing to the pipe multiple
times if callbacks are added faster than the loop is able to process
them.  Previously, this would lead to the loop performing multiple read
iterations from pipe unnecessarily.

Sponsored by: The FreeBSD Foundation

Differential Revision: https://reviews.llvm.org/D135516
2022-10-17 17:48:44 +02:00
David Spickett
812ad2167b [LLDB] Change RegisterValue::SetFromMemoryData to const RegisterInfo&
All callers were either assuming their pointer was not null before calling
this, or checking beforehand.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D135668
2022-10-12 08:10:24 +00:00
David Spickett
c7ddbd62d8 [LLDB] Change RegisterValue::GetAsMemoryData to const RegisterInfo&
Most of the paths to this never passed nullptr intentionally. Those
that possibly could have were assuming it was not null elsehwere,
so would have crashed.

I've added asserts in those cases.

At least one case was relying on GetAsMemoryData to return an error
when it was given nullptr. So I've hoisted that error setting code
out into the caller.

Depends on D134963

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D134965
2022-10-11 13:59:05 +00:00
Martin Storsjö
e9e3a612ec [lldb] Fix warnings about unused variables when building without asserts. NFC. 2022-10-01 14:27:48 +03:00
Jonas Devlieghere
70599d7027
[lldb] Remove LLDB reproducers
This patch removes the remaining reproducer code. The SBReproducer class
remains for ABI stability but is just an empty shell. This completes the
removal process outlined on the mailing list [1].

[1] https://lists.llvm.org/pipermail/lldb-dev/2021-September/017045.html
2022-09-19 14:43:31 -07:00
Pavel Labath
681d0d9e5f [lldb-server] Report launch error in vRun packets
Uses our existing "error string" extension to provide a better
indication of why the launch failed (the client does not make use of the
error yet).

Also, fix the way we obtain the launch error message (make sure we read
the whole message, and skip trailing garbage), and reduce the size of
TestLldbGdbServer by splitting some tests into a separate file.

Differential Revision: https://reviews.llvm.org/D133352
2022-09-09 15:10:38 +02:00
Joe Loser
47b76631e7 [lldb] Use std::size instead of llvm::array_lengthof
LLVM contains a helpful function for getting the size of a C-style
array: `llvm::array_lengthof`. This is useful prior to C++17, but not as
helpful for C++17 or later: `std::size` already has support for C-style
arrays.

Change call sites to use `std::size` instead.

Differential Revision: https://reviews.llvm.org/D133501
2022-09-08 14:21:55 -06:00
Pavel Labath
6a8bbd26ab [lldb] Enable the insertion of "pending callbacks" to MainLoops from other threads
This will be used as a replacement for selecting over a pipe fd, which
does not work on windows. The posix implementation still uses a pipe
under the hood, while the windows version uses windows event handles.

The idea is that, instead of writing to a pipe, one just inserts a
callback, which does whatever you wanted to do after the bytes come out
the read end of the pipe.

Differential Revision: https://reviews.llvm.org/D131160
2022-09-06 10:56:10 +02:00
Jim Ingham
5ad6ed0e55 Change the meaning of a UUID with all zeros for data.
Previously, depending on how you constructed a UUID from data or a
StringRef, an input value of all zeros was valid (e.g. setFromData)
or not (e.g. setFromOptionalData).  Since there was no way to tell
which interpretation to use, it was done somewhat inconsistently.
This standardizes the meaning of a UUID of all zeros to Not Valid,
and removes all the Optional methods and their uses, as well as the
static factories that supported them.

Differential Revision: https://reviews.llvm.org/D132191
2022-08-30 10:17:58 -07:00
Martin Storsjö
118038e878 [lldb] Use the NativeSock type instead of plain 'int'
This fixes a warning when building for Windows:

    ../tools/lldb/source/Host/common/TCPSocket.cpp:297:16: warning: comparison of integers of different signs: 'int' and 'const NativeSocket' (aka 'const unsigned long long') [-Wsign-compare]
          if (sock != kInvalidSocketValue) {
              ~~~~ ^  ~~~~~~~~~~~~~~~~~~~

Differential Revision: https://reviews.llvm.org/D132841
2022-08-30 10:07:44 +03:00
Martin Storsjö
5f0080fbe8 [lldb] Fix warnings about unused variables when building without asserts. NFC. 2022-08-29 13:25:38 +03:00
John Ericson
3adda398ce [clang][lldb][cmake] Use new *_INSTALL_LIBDIR_BASENAME CPP macro
Use this instead of `*_LIBDIR_SUFFIX`, from which it is computed.

This gets us ready for D130586, in which `*_LIBDIR_SUFFIX` is
deprecated.

Differential Revision: https://reviews.llvm.org/D132300
2022-08-20 12:52:21 -04:00
Kazu Hirata
c38bc421b1 [lldb] Use Optional::value instead of Optional::getValue (NFC) 2022-08-19 21:40:48 -07:00
Pavel Labath
c74c17f37a [lldb] Use WSAEventSelect for MainLoop polling on windows
This patch switches the MainLoop class to use the WSAEventSelect
mechanism to wait for multiple sockets to become readable. The
motivation for doing that is that this allows us to wait for other kinds
of events as well (as long as they can be converted to WSAEvents). This
will allow us to avoid (abstract away) pipe-based multiplexing
mechanisms in the generic code, since pipes cannot be combined with
sockets on windows.

Since the windows implementation will now look completely different than
the posix (file descriptor-based) implementations, I have split the
MainLoop class into two (MainLoopPosix and MainLoopWindows), with the
common code going into MainLoopBase.

Differential Revision: https://reviews.llvm.org/D131159
2022-08-19 13:25:25 +02:00
John Ericson
e941b031d3 Revert "[cmake] Use CMAKE_INSTALL_LIBDIR too"
This reverts commit f7a33090a91015836497c75f173775392ab0304d.

Unfortunately this causes a number of failures that didn't show up in my
local build.
2022-08-18 22:46:32 -04:00
John Ericson
f7a33090a9 [cmake] Use CMAKE_INSTALL_LIBDIR too
We held off on this before as `LLVM_LIBDIR_SUFFIX` conflicted with it.
Now we return this.

`LLVM_LIBDIR_SUFFIX` is kept as a deprecated way to set
`CMAKE_INSTALL_LIBDIR`. The other `*_LIBDIR_SUFFIX` are just removed
entirely.

I imagine this is too potentially-breaking to make LLVM 15. That's fine.
I have a more minimal version of this in the disto (NixOS) patches for
LLVM 15 (like previous versions). This more expansive version I will
test harder after the release is cut.

Reviewed By: sebastian-ne, ldionne, #libc, #libc_abi

Differential Revision: https://reviews.llvm.org/D130586
2022-08-18 15:33:35 -04:00
Slava Gurevich
5a197772ee [LLDB][NFC] Suppress spurious static inspection warnings
Suppress coverity false positives.
This diff contains comments only, including the hints for Coverity static code inspection
to suppress the warning originating at the next line after the comment.

Differential Revision: https://reviews.llvm.org/D131998
2022-08-17 16:12:42 -07:00
Jonas Devlieghere
570e10cb9d
[lldb] Fix warning: comparison of integers of different signs
Fixes a warning about comparison of integers of different signs
'wchar_t' and 'int' in Editline.cpp:

      return out != (int)WEOF;
             ~~~ ^  ~~~~~~~~~
2022-08-15 11:25:46 -07:00
Kazu Hirata
448c466636 Use llvm::erase_value (NFC) 2022-08-13 12:55:50 -07:00
Slava Gurevich
256ba7738e [LLDB][NFC] Fix the style issue in TCPSocket
Style fixes for the entire file

Differential Revision: https://reviews.llvm.org/D131543
2022-08-11 18:02:01 -07:00
Emmmer
0247b5aaae [LLDB][RISCV] Add riscv software breakpoint trap code
Added:
- Take RISC-V `ebreak` instruction as breakpoint trap code, so our breakpoint works as expected now.

Further work:
- RISC-V does not support hardware single stepping yet. A software implementation may come in future PR.
- Add support for RVC extension (the trap code, etc.).

Reviewed By: DavidSpickett

Differential Revision: https://reviews.llvm.org/D131566
2022-08-11 14:26:22 +08:00
Emmmer
7bece0f03b [LLDB][RISCV] Add riscv register definition and read/write
This patch is based on the minimal extract of D128250.

What is implemented:
- Use the same register layout as Linux kernel and mock read/write for `x0` register (the always zero register).
- Refactor some duplicate code, and delete unused register definitions.

Reviewed By: DavidSpickett

Differential Revision: https://reviews.llvm.org/D130342
2022-08-11 14:24:06 +08:00
Slava Gurevich
aa4977f2e1 [LLDB][NFC] Reliability fixes to TCPSocket code
Patch the following issues found by static code inspection:
- Unchecked return values from lib calls
- Passing potentially negative arg into a function that requires non-negative input
- Possible socket double-close

Differential Revision: https://reviews.llvm.org/D131294
2022-08-06 23:06:55 -07:00
Jonas Devlieghere
71ebcd3348
[lldb] Make LLDB resilient against failing dyld introspection SPIs
Make LLDB resilient against failing dyld introspection SPIs:

 - dyld_process_create_for_current_task
 - dyld_process_snapshot_create_for_process
 - dyld_process_snapshot_get_shared_cache

These can all fail and return a nullptr. Instead of having an assert,
which doesn't really make sense, as we have no control over whether
these calls succeed or not, bail out gracefully and use the fallback
logic.

rdar://98070414

Differential revision: https://reviews.llvm.org/D131110
2022-08-03 15:47:58 -07:00
Jonas Devlieghere
9ffcc85fbe
Revert "Revert "[lldb][modules] Disable Clang Modules in source/Host directory on macOS""
This reverts commit c7bd61d4a79b88dbd97028bb0a73a73b2d6aca89 because it
breaks the underlying issue is apparently not yet resolved. This only
affects the modules build.
2022-08-03 14:39:45 -07:00
Jonas Devlieghere
c7bd61d4a7
Revert "[lldb][modules] Disable Clang Modules in source/Host directory on macOS"
This reverts commit 7cf4ab13af8aa3183e551b3319399cddd9384948 as it was a
temporary workaround that's no longer needed.
2022-08-02 16:14:02 -07:00
Greg Clayton
529a3d87a7 [NFC] Improve FileSpec internal APIs and usage in preparation for adding caching of resolved/absolute.
Resubmission of https://reviews.llvm.org/D130309 with the 2 patches that fixed the linux buildbot, and new windows fixes.

The FileSpec APIs allow users to modify instance variables directly by getting a non const reference to the directory and filename instance variables. This makes it impossible to control all of the times the FileSpec object is modified so we can clear cached member variables like m_resolved and with an upcoming patch caching if the file is relative or absolute. This patch modifies the APIs of FileSpec so no one can modify the directory or filename instance variables directly by adding set accessors and by removing the get accessors that are non const.

Many clients were using FileSpec::GetCString(...) which returned a unique C string from a ConstString'ified version of the result of GetPath() which returned a std::string. This caused many locations to use this convenient function incorrectly and could cause many strings to be added to the constant string pool that didn't need to. Most clients were converted to using FileSpec::GetPath().c_str() when possible. Other clients were modified to use the newly renamed version of this function which returns an actualy ConstString:

ConstString FileSpec::GetPathAsConstString(bool denormalize = true) const;

This avoids the issue where people were getting an already uniqued "const char *" that came from a ConstString only to put the "const char *" back into a "ConstString" object. By returning the ConstString instead of a "const char *" clients can be more efficient with the result.

The patch:
- Removes the non const GetDirectory() and GetFilename() get accessors
- Adds set accessors to replace the above functions: SetDirectory() and SetFilename().
- Adds ClearDirectory() and ClearFilename() to replace usage of the FileSpec::GetDirectory().Clear()/FileSpec::GetFilename().Clear() call sites
- Fixed all incorrect usage of FileSpec::GetCString() to use FileSpec::GetPath().c_str() where appropriate, and updated other call sites that wanted a ConstString to use the newly returned ConstString appropriately and efficiently.

Differential Revision: https://reviews.llvm.org/D130549
2022-07-28 13:28:26 -07:00
Slava Gurevich
24301569f0 [LLDB][NFC][Reliability] Fix uninitialized variables from Coverity scan. Part 3
Improve LLDB reliability by fixing the following "uninitialized variables" static code inspection warnings from
scan.coverity.com/projects/llvm:

1355854, 1347549, 1316348, 1372028, 1431625,
1315634, 1315637, 1355855, 1364803, 1420505,
1420563, 1420685, 1366014, 1203966, 1204029,
1204031, 1204032, 1328411, 1325969, 1325968,
1374921, 1094809

Differential Revision: https://reviews.llvm.org/D130602
2022-07-27 10:39:49 -07:00
Kazu Hirata
559463e94e [lldb] Use true instead of 0 (NFC)
Identified with modernize-use-bool-literals.
2022-07-24 12:27:06 -07:00
Nico Weber
1b4b12a340 Revert "[NFC] Improve FileSpec internal APIs and usage in preparation for adding caching of resolved/absolute." and follow-ups
This reverts commit 9429b67b8e300e638d7828bbcb95585f85c4df4d.

It broke the build on Windows, see comments on https://reviews.llvm.org/D130309

It also reverts these follow-ups:

Revert "Fix buildbot breakage after https://reviews.llvm.org/D130309."
This reverts commit f959d815f4637890ebbacca379f1c38ab47e4e14.

Revert "Fix buildbot breakage after https://reviews.llvm.org/D130309."
This reverts commit 0bbce7a4c2d2bff622bdadd4323f93f5d90e6d24.

Revert "Cache the value for absolute path in FileSpec."
This reverts commit dabe877248b85b34878e75d5510339325ee087d0.
2022-07-23 12:35:48 -04:00
Greg Clayton
0bbce7a4c2 Fix buildbot breakage after https://reviews.llvm.org/D130309. 2022-07-22 13:59:06 -07:00
Greg Clayton
f959d815f4 Fix buildbot breakage after https://reviews.llvm.org/D130309. 2022-07-22 13:24:26 -07:00
Greg Clayton
9429b67b8e [NFC] Improve FileSpec internal APIs and usage in preparation for adding caching of resolved/absolute.
The FileSpect APIs allow users to modify instance variables directly by getting a non const reference to the directory and filename instance variables. This makes it impossibly to control all of the times the FileSpec object is modified so we can clear the cache. This patch modifies the APIs of FileSpec so no one can modify the directory or filename directly by adding set accessors and by removing the get accessors that are non const.

Many clients were using FileSpec::GetCString(...) which returned a unique C string from a ConstString'ified version of the result of GetPath() which returned a std::string. This caused many locations to use this convenient function incorrectly and could cause many strings to be added to the constant string pool that didn't need to. Most clients were converted to using FileSpec::GetPath().c_str() when possible. Other clients were modified to use the newly renamed version of this function which returns an actualy ConstString:
    ConstString FileSpec::GetPathAsConstString(bool denormalize = true) const;

This avoids the issue where people were getting an already uniqued "const char *" that came from a ConstString only to put the "const char *" back into a "ConstString" object. By returning the ConstString instead of a "const char *" clients can be more efficient with the result.

The patch:
- Removes the non const GetDirectory() and GetFilename() get accessors
- Adds set accessors to replace the above functions: SetDirectory() and SetFilename().
- Adds ClearDirectory() and ClearFilename() to replace usage of the FileSpec::GetDirectory().Clear()/FileSpec::GetFilename().Clear() call sites
- Fixed all incorrect usage of FileSpec::GetCString() to use FileSpec::GetPath().c_str() where appropriate, and updated other call sites that wanted a ConstString to use the newly returned ConstString appropriately and efficiently.

Differential Revision: https://reviews.llvm.org/D130309
2022-07-22 10:12:31 -07:00
Kazu Hirata
5cff5142a8 Use value instead of getValue (NFC) 2022-07-15 20:03:13 -07:00
Jonas Devlieghere
9bdb7e5734
[lldb] Add a log dump command
Add a log dump command to dump logs to a file. This only works for
channels that have a log handler associated that supports dumping. For
now that's limited to the circular log handler, but more could be added
in the future.

Differential revision: https://reviews.llvm.org/D128557
2022-06-27 10:02:34 -07:00
Kazu Hirata
3b7c3a654c Revert "Don't use Optional::hasValue (NFC)"
This reverts commit aa8feeefd3ac6c78ee8f67bf033976fc7d68bc6d.
2022-06-25 11:56:50 -07:00
Kazu Hirata
aa8feeefd3 Don't use Optional::hasValue (NFC) 2022-06-25 11:55:57 -07:00
Jonas Devlieghere
87a3293961
[lldb] Move Host::SystemLog out of !defined(_WIN32)
The definition of Host::SystemLog was (unintentionally) guarded by
!defined(_WIN32).
2022-06-24 11:18:31 -07:00
Jonas Devlieghere
1e5d5261e2
[lldb] Add SystemLogHandler for emitting log messages to the system log
Add a system log handler that emits log messages to the operating system
log. In addition to the log handler itself, this patch also introduces a
new Host::SystemLog helper function to abstract over writing to the
system log.

Differential revision: https://reviews.llvm.org/D128321
2022-06-24 10:53:15 -07:00
Jonas Devlieghere
6879391908
[lldb] Replace Host::SystemLog with Debugger::Report{Error,Warning}
As it exists today, Host::SystemLog is used exclusively for error
reporting. With the introduction of diagnostic events, we have a better
way of reporting those. Instead of printing directly to stderr, these
messages now get printed to the debugger's error stream (when using the
default event handler). Alternatively, if someone is listening for these
events, they can decide how to display them, for example in the context
of an IDE such as Xcode.

This change also means we no longer write these messages to the system
log on Darwin. As far as I know, nobody is relying on this, but I think
this is something we could add to the diagnostic event mechanism.

Differential revision: https://reviews.llvm.org/D128480
2022-06-24 09:46:26 -07:00
Michał Górny
5b04eb23ae [lldb] [MainLoop] Support "pending callbacks", to be called once
Support adding a "pending callback" to the main loop, that will be
called once after all the pending events are processed.  This can be
e.g. to defer destroying the process instance until its exit is fully
processed, as suggested in D127500.

Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.llvm.org/D128253
2022-06-21 19:47:30 +02:00
Jonas Devlieghere
9916633997
[lldb] Fix modernize-use-override warnings (NFC)
Fix modernize-use-override warnings. Because this check is listed in
LLDB's top level .clang-tidy configuration, the check is enabled by
default and the resulting warnings show up in my editor.

I've audited the modified lines. This is not a blind change.
2022-06-17 15:08:02 -07:00
Walter Erquinigo
a758205951 [trace][intelpt] Support system-wide tracing [9] - Collect and return context switch traces
- Add collection of context switches per cpu grouped with the per-cpu intel pt traces.
- Move the state handling from the interl pt trace class to the PerfEvent one.
- Add support for stopping and enabling perf event groups.
- Return context switch entries as part of the jLLDBTraceGetState response.
- Move the triggers of whenever the process stopped or resumed. Now the will-resume notification is in a better location, which will ensure that we'll capture the instructions that will be executed.
- Remove IntelPTSingleBufferTraceUP. The unique pointer was useless.
- Add unit tests

Differential Revision: https://reviews.llvm.org/D125897
2022-06-15 12:07:59 -07:00
Pavel Labath
cf2c8e419d [lldb] Fix TestDyldExecLinux with xml enabled
NativeProcessLinux is not able to properly read libraries-svr4 data when
running with ld.so as the "main" executable. Normally, this is not a big
problem, as it returns an error message, and lldb can fallback to manual
library loading.

Unfortunately, lldb-server also does not clear cached svr4 data on exec,
which means that it does *not* return an error when the application
execs from the "regular" to the "ld.so" mode. Instead it returns
incorrect data (it is missing the main executable) and causes
TestDyldExecLinux to fail (but only when building with xml support
enabled).

This patch makes ensures that cached process data is cleared on exec,
fixing the test. Since TestDyldExecLinux has shown to be sensitive to
the way we read library info, I fork it into two (with svr4 enabled and
disabled).
2022-06-14 11:44:59 +02:00
Pavel Labath
926a7ecdc8 [lldb] Fix TCPSocket::Connect when getaddrinfo returns multiple addrs
TCPSocket::Connect() calls SocketAddress::GetAddressInfo() and tries to
connect any of them (in a for loop).

This used to work before commit 4f6d3a376c9f("[LLDB] Fix setting of
success in Socket::Close()") https://reviews.llvm.org/D116768.

As a side effect of that commit, TCPSocket can only connect to the first
address returned by SocketAddress::GetAddressInfo().

1. If the attempt to connect to the first address fails,
   TCPSocket::Connect(), calls CLOSE_SOCKET(GetNativeSocket()), which
   closes the fd, but DOES NOT set m_socket to kInvalidSocketValue.
2. On the second attempt, TCPSocket::CreateSocket() calls
   Socket::Close().
3. Socket::Close() proceeds, because IsValid() is true (m_socket was not
   reset on step 1).
4. Socket::Close() calls ::close(m_socket), which fails
5. Since commit 4f6d3a376c9f("[LLDB] Fix setting of success in
   Socket::Close()"), this is error is detected. Socket::Close() returns
   an error.
6. TCPSocket::CreateSocket() therefore returns an error.
7. TCPSocket::Connect() detects the error and continues, skipping the
   second (and the third, fourth...) address.

This commit fixes the problem by changing step 1: by calling
Socket::Close, instead of directly calling close(m_socket), m_socket is
also se to kInvalidSocketValue. On step 3, Socket::Close() is going to
return immediately and, on step 6, TCPSocket::CreateSocket() does not
fail.

How to reproduce this problem:

On my system, getaddrinfo() resolves "localhost" to "::1" (first) and to
"127.0.0.1" (second).

Start a gdbserver that only listens on 127.0.0.1:

```
gdbserver 127.0.0.1:2159 /bin/cat
Process /bin/cat created; pid = 2146709
Listening on port 2159
```

Start lldb and make it connect to "localhost:2159"

```
./bin/lldb
(lldb) gdb-remote localhost:2159
```

Before 4f6d3a376c9f("[LLDB] Fix setting of success in Socket::Close()"),
this used to work. After that commit, it stopped working. This commit
fixes the problem.

Reviewed By: labath

Differential Revision: https://reviews.llvm.org/D126702
2022-06-14 08:49:02 +02:00
Kazu Hirata
4391625255 [lldb] Fix an unused function warning
This patch fixes:

  .../llvm-project/lldb/source/Host/common/PseudoTerminal.cpp:106:20:
  error: unused function 'use_ptsname' [-Werror,-Wunused-function]
2022-05-25 09:49:05 -07:00
Jonas Devlieghere
ea4864007c
[lldb] Fix 'ptsname_r' is only available on macOS 10.13.4 or newer
A deployment target less than 10.13.4 causes an error saying that
'ptsname_r' is only available on macOS 10.13.4 or newer. The current
logic only checks if the symbol is available and doesn't account for the
deployment target. This patch fixes that by adding an availability
check.

Differential revision: https://reviews.llvm.org/D125995
2022-05-19 21:39:52 -07:00
Walter Erquinigo
1637545f68 [trace][intelpt] Support system-wide tracing [5] - Disable/enable per-core tracing based on the process state
When tracing on per-core mode, we are tracing all processes, which means
that after hitting a breakpoint, our process will stop running (thus
producing no more tracing data) but other processes will continue
writing to our trace buffers. This causes a big data loss for our trace.
As a way to remediate this, I'm adding some logic to pause and unpause
tracing based on the target's state. The earlier we do it the better,
however, I'm not adding the trigger at the earliest possible point for
simplicity of this diff. Later we can improve that part.

Differential Revision: https://reviews.llvm.org/D124962
2022-05-17 12:46:54 -07:00