Commit Graph

2210 Commits

Author SHA1 Message Date
Reid Kleckner 89b57061f7 Move TargetRegistry.(h|cpp) from Support to MC
This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.

This allows us to ensure that Support doesn't have includes from MC/*.

Differential Revision: https://reviews.llvm.org/D111454
2021-10-08 14:51:48 -07:00
Pavel Labath 3d7161e3c1 [lldb] Remove shared_ptr from some global Properties objects
they're unnecessary, make the code longer, and their removal actually
ensures proper initialization in multithreaded scenarios.
2021-10-08 10:43:37 +02:00
Pavel Labath 202af507fd Recommit: [lldb] Remove "dwarf dynamic register size expressions" from RegisterInfo
The previous version of the patch did not update the definitions in
conditionally compiled code. This patch includes changes to ARC and
windows targets.

Original commit message was:

These were added to support some mips registers on linux, but linux mips
support has now been removed due.

They are still referenced in the freebds mips implementation, but the
completeness of that implementation is also unknown. All other
architectures just set these fields to zero, which is a cause of
significant bloat in our register info definitions.

Arm also has registers with variable sizes, but they were implemented in
a more gdb-compatible fashion and don't use this feature.

Differential Revision: https://reviews.llvm.org/D110914
2021-10-07 11:15:00 +02:00
Michael Forster b2c906da19 Revert "[lldb] Remove "dwarf dynamic register size expressions" from RegisterInfo"
This reverts commit 00e704bf08.

This commit should should have updated
llvm/llvm-project/lldb/source/Plugins/ABI/ARC/ABISysV_arc.cpp like the other
architectures.
2021-10-06 18:15:25 +02:00
Pavel Labath 00e704bf08 [lldb] Remove "dwarf dynamic register size expressions" from RegisterInfo
These were added to support some mips registers on linux, but linux mips
support has now been removed due.

They are still referenced in the freebds mips implementation, but the
completeness of that implementation is also unknown. All other
architectures just set these fields to zero, which is a cause of
significant bloat in our register info definitions.

Arm also has registers with variable sizes, but they were implemented in
a more gdb-compatible fashion and don't use this feature.

Differential Revision: https://reviews.llvm.org/D110914
2021-10-06 13:22:38 +02:00
Michał Górny 214054f78a [lldb] Move DynamicRegisterInfo to public Target library
Move DynamicRegisterInfo from the internal lldbPluginProcessUtility
library to the public lldbTarget library.  This is a prerequisite
towards ABI plugin changes that are going to pass DynamicRegisterInfo
parameters.

Differential Revision: https://reviews.llvm.org/D110942
2021-10-05 12:40:55 +02:00
Michał Górny 58b4501eea [lldb] [Host] Refactor TerminalState
Refactor TerminalState to make the code simpler.  Move 'struct termios'
to a PImpl-style subclass.  Add an RAII interface to automatically store
and restore the state.

Differential revision: https://reviews.llvm.org/D110721
2021-10-01 12:53:21 +02:00
Pavel Labath 156cb4cc64 [lldb] Remove non-stop mode code
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
2021-09-28 14:13:50 +02:00
Michał Górny 3a6ba36751 [lldb] Convert misc. StringConvert uses
Replace misc. StringConvert uses with llvm::to_integer()
and llvm::to_float(), except for cases where further refactoring is
planned.  The purpose of this change is to eliminate the StringConvert
API that is duplicate to LLVM, and less correct in behavior at the same
time.

Differential Revision: https://reviews.llvm.org/D110447
2021-09-25 14:19:19 +02:00
Pavel Labath 966922320f [lldb] Remove two #ifndef linux from Platform.cpp
These have been here since r215992, guarding the calls to HostInfo, but
their purpose unclear -- HostInfoLinux provides these functions and they
work fine.
2021-09-20 08:30:02 +02:00
Pavel Labath bd590a5f89 [lldb] Make Platform::DebugProcess take a Target reference
instead of a pointer. There are just two callers of this function, and
both of them have a valid target pointer, so there's no need for all
implementations to concern themselves with whether the pointer is null.
2021-09-16 11:33:47 +02:00
Michał Górny 8567f4d4b9 [lldb] Support querying registers via generic names without alt_names
Update GetRegisterInfoByName() methods to support getting registers
by a generic name independently of alt_name entries in the register
context.  This makes it possible to use generic names when interacting
with gdbserver (that does not supply alt_names).  It also makes it
possible to remove some of the duplicated information from register
context declarations and/or use alt_names for another purpose.

Differential Revision: https://reviews.llvm.org/D108554
2021-09-13 13:05:06 +02:00
Pavel Labath b03126768a [lldb] Remove PluginInterface::GetPluginVersion
In all these years, we haven't found a use for this function (it has
zero callers). Lets just remove the boilerplate.

Differential Revision: https://reviews.llvm.org/D109600
2021-09-13 10:29:00 +02:00
Raphael Isemann 0c8444bd34 [lldb] Fix Clang modules build after D101329
D101329 introduces the Process:SaveCore function returning a
`llvm::Expected<bool>`. That function causes that Clang with -fmodules crashes
while compiling LLDB's PythonDataObjects.cpp. With enabled asserts Clang fails
because of:

    Assertion failed: (CachedFieldIndex && "failed to find field in parent")

Crash can be reproduced by building via -DLLVM_ENABLE_MODULES=On with Clang
12.0.1 and then building PythonDataObjects.cpp.o .

Clang bug is tracked at rdar://82901462
2021-09-10 13:10:19 +02:00
Michał Górny 4a2a947317 [lldb] [client] Implement follow-fork-mode
Implement a new target.process.follow-fork-mode setting to control
LLDB's behavior on fork.  If set to 'parent', the forked child is
detached and parent continues being traced.  If set to 'child',
the parent is detached and child becomes traced instead.

Differential Revision: https://reviews.llvm.org/D100503
2021-09-02 12:16:58 +02:00
Alex Langford 862a311301 [lldb] Tighten lock in Language::ForEach
It is easy to accidentally introduce a deadlock by having the callback
passed to Language::ForEach also attempt to acquire the same lock. It
is easy enough to disallow the callback from calling anything in
Language directly, but it may happen through a series of other
function/method calls.

The solution I am proposing is to tighten the lock in Language::ForEach
so that it is only held as we gather the currently loaded language
plugins. We store them in a vector and then iterate through them with
the callback so that the callback can't introduce a deadlock.

Differential Revision: https://reviews.llvm.org/D109013
2021-08-31 15:45:38 -07:00
Michał Górny 0a1d80d56e [lldb] [gdb-remote client] Support minimal fork/vfork handling
Add a support for handling fork/vfork stops in LLGS client.  At this
point, it only sends a detach packet for the newly forked child
(and implicitly resumes the parent).

Differential Revision: https://reviews.llvm.org/D100206
2021-08-30 10:24:38 +02:00
Omar Emara 82507f1798 [LLDB][GUI] Add Process Launch form
This patch adds a process launch form. Additionally, a LazyBoolean field
was implemented and numerous utility methods were added to various
fields to get the launch form working.

Differential Revision: https://reviews.llvm.org/D107869
2021-08-18 15:43:30 -07:00
Michał Górny 14735cab65 [lldb] [gdb-remote] Add eOpenOptionReadWrite for future gdb compat
Modify OpenOptions enum to open the future path into synchronizing
vFile:open bits with GDB.  Currently, LLDB and GDB use different flag
models effectively making it impossible to match bits.  Notably, LLDB
uses two bits to indicate read and write status, and uses union of both
for read/write.  GDB uses a value of 0 for read-only, 1 for write-only
and 2 for read/write.

In order to future-proof the code for the GDB variant:

1. Add a distinct eOpenOptionReadWrite constant to be used instead
   of (eOpenOptionRead | eOpenOptionWrite) when R/W access is required.

2. Rename eOpenOptionRead and eOpenOptionWrite to eOpenOptionReadOnly
   and eOpenOptionWriteOnly respectively, to make it clear that they
   do not mean to be combined and require update to all call sites.

3. Use the intersection of all three flags when matching against
   the three possible values.

This commit does not change the actual bits used by LLDB.

Differential Revision: https://reviews.llvm.org/D106984
2021-08-09 12:06:59 +02:00
Dave Lee 41d0b20cc9 [lldb] Avoid moving ThreadPlanSP from plans vector
Change `ThreadPlanStack::PopPlan` and `::DiscardPlan` to not do the following:

1. Move the last plan, leaving a moved `ThreadPlanSP` in the plans vector
2. Operate on the last plan
3. Pop the last plan off the plans vector

This leaves a period of time where the last element in the plans vector has been moved. I am not sure what, if any, guarantees there are when doing this, but it seems like it would/could leave a null `ThreadPlanSP` in the container. There are asserts in place to prevent empty/null `ThreadPlanSP` instances from being pushed on to the stack, and so this could break that invariant during multithreaded access to the thread plan stack.

An open question is whether this use of `std::move` was the result of a measure performance problem.

Differential Revision: https://reviews.llvm.org/D106171
2021-08-01 10:40:04 -07:00
Stella Stamenova 66ba4e3dc6 Revert "[lldb] Assert filecache and live memory match on debug under a setting"
This reverts commit 77e9d10f0f.

This change broke the Windows LLDB bot:
https://lab.llvm.org/buildbot/#/builders/83/builds/8784/steps/7/logs/stdio
2021-07-29 10:48:57 -07:00
Augusto Noronha 77e9d10f0f [lldb] Assert filecache and live memory match on debug under a setting 2021-07-29 10:29:34 -03:00
Jim Ingham 910353c104 When calculating the "currently selected thread" in
Process::HandleStateChangedEvent, we check whether a thread stopped
for eStopReasonSignal is stopped for a signal that's currently set to
"no-stop". If it is, then we don't set that thread as the currently
selected thread.

But that only happens in the part of the algorithm that's handling the
case where the previously selected thread has no stop reason. Since we
want to keep on a thread as long as it is doing something interesting,
we always prefer the current thread. That's almost right, but we
forgot to check whether the previously selected thread stopped with an
eStopReasonSignal for a "no-stop" signal. If it did, then we shouldn't
select it.

This patch adds that check. I can't figure out a good way to test
this. This is the sort of thing that Ismail's scripted process plugin
will make easy once it is a real boy. But figuring out how to do this
in a real process is not trivial.

Differential Revision: https://reviews.llvm.org/D106712
2021-07-27 13:38:09 -07:00
David Spickett 5ea091a817 [lldb][AArch64] Add memory tag writing to lldb
This adds memory tag writing to Process and the
GDB remote code. Supporting work for the
"memory tag write" command. (to follow)

Process WriteMemoryTags is similair to ReadMemoryTags.
It will pack the tags then call DoWriteMemoryTags.
That function will send the QMemTags packet to the gdb-remote.

The QMemTags packet follows the GDB specification in:
https://sourceware.org/gdb/current/onlinedocs/gdb/General-Query-Packets.html#General-Query-Packets

Note that lldb-server will be treating partial writes as
complete failures. So lldb doesn't need to handle the partial
write case in any special way.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D105181
2021-07-27 15:18:42 +01:00
Walter Erquinigo c1b4632528 [trace] Add the definition of a TraceExporter plugin
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
2021-07-26 18:01:50 -07:00
Walter Erquinigo ef8c6849a2 [source maps] fix source mapping when there are multiple matching rules
D104406 introduced an error in which, if there are multiple matchings rules for a given path, lldb was only checking for the validity in the filesystem of the first match instead of looking exhaustively one by one until a valid file is found.

Besides that, a call to consume_front was being done incorrectly, as it was modifying the input, which renders subsequent matches incorrect.

I added a test that checks for both cases.

Differential Revision: https://reviews.llvm.org/D106723
2021-07-23 17:53:12 -07:00
Jim Ingham bcce8e0fcc Fix the logic so stop-hooks get run after a breakpoint that ran an expression
Code was added to Target::RunStopHook to make sure that we don't run stop hooks when
you stop after an expression evaluation. But the way it was done was to check that we
hadn't run an expression since the last natural stop. That failed in the case where you
stopped for a breakpoint which had run an expression, because the stop-hooks get run
after the breakpoint actions, and so by the time we got to running the stop-hooks,
we had already run a user expression.

I fixed this by adding a target ivar tracking the last natural stop ID at which we had
run a stop-hook. Then we keep track of this and make sure we run the stop-hooks only
once per natural stop.

Differential Revision: https://reviews.llvm.org/D106514
2021-07-22 15:06:41 -07:00
Med Ismail Bennani 312b43da05 [lldb/Plugins] Add ScriptedProcess Process Plugin
This patch introduces Scripted Processes to lldb.

The goal, here, is to be able to attach in the debugger to fake processes
that are backed by script files (in Python, Lua, Swift, etc ...) and
inspect them statically.

Scripted Processes can be used in cooperative multithreading environments
like the XNU Kernel or other real-time operating systems, but it can
also help us improve the debugger testing infrastructure by writting
synthetic tests that simulates hard-to-reproduce process/thread states.

Although ScriptedProcess is not feature-complete at the moment, it has
basic execution capabilities and will improve in the following patches.

rdar://65508855

Differential Revision: https://reviews.llvm.org/D100384

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-07-22 14:47:33 +02:00
Alex Langford 8e6b31c395 [LLDB] Move Trace-specific classes into separate library
These two classes, TraceSessionFileParser and ThreadPostMortemTrace,
seem to be useful primarily for tracing. Currently it looks like
intel-pt is the sole user of these, but that other tracing plugins could
be written in the future that take advantage of these. Unfortunately
with them in Target, there is a dependency on PluginProcessUtility. I'd
like to sever that dependency, so I moved them into a `TraceCommon`
plugin.

Differential Revision: https://reviews.llvm.org/D105649
2021-07-21 13:28:34 -07:00
Walter Erquinigo 04195843ef [intel pt] Add TSC timestamps
Differential Revision: https://reviews.llvm.org/D106328
2021-07-20 16:29:17 -07:00
Benjamin Kramer aa09d1f9c9 [lldb] Remove unused variable. NFCI 2021-07-20 10:34:05 +02:00
Michał Górny 7b54b1cdaf [lldb] Make WatchpointList iterable
Based on de448c0a9e.

Differential Revision: https://reviews.llvm.org/D106263
2021-07-20 07:47:48 +02:00
Jim Ingham 2656af95eb Don't use !eStateRunning when you mean eStateStopped in DestroyImpl.
When we go to destroy the process, we first try to halt it, if
we succeeded and the target stopped, we want to clear out the
thread plans and breakpoints in case we still need to resume to complete
killing the process.  If the target was exited or detached, it's
pointless but harmless to do this.  But if the state is eStateInvalid -
for instance if we tried to interrupt the target to Halt it and that
fails - we don't want to keep trying to interact with the inferior,
so we shouldn't do this work.

This change explicitly checks eStateStopped, and only does the pre-resume
cleanup if we did manage to stop the process.
2021-07-19 14:30:04 -07:00
Walter Erquinigo b0aa70761b [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
2021-07-16 16:47:43 -07:00
Jim Ingham 6eb576dcff Add a mutex to guard access to the ThreadPlanStack class
We've seen reports of crashes (none we've been able to reproduce
locally) that look like they are caused by concurrent access to a
thread plan stack.  It looks like there are error paths when an
interrupt request to debugserver times out that cause this problem.

The thread plan stack access is never in a hot loop, and there
aren't enough of them for the extra data member to matter, so
there's really no good reason not to protect the access.

Adding the mutex revealed a couple of places where we were
using "auto" in an iteration when we should have been using
"auto &" - we didn't intend to copy the stack - and I fixed
those as well.

Except for preventing crashes this should be NFC.

Differential Revision: https\://reviews.llvm.org/D106122
2021-07-16 15:40:58 -07:00
David Spickett d046fb62b7 [lldb][AArch64] Refactor memory tag range handling
Previously GetMemoryTagManager checked many things in one:
* architecture supports memory tagging
* process supports memory tagging
* memory range isn't inverted
* memory range is all tagged

Since writing follow up patches for tag writing (in review
at the moment) it has become clear that this gets unwieldy
once we add the features needed for that.

It also implies that the memory tag manager is tied to the
range you used to request it with but it is not. It's a per
process object.

Instead:
* GetMemoryTagManager just checks architecture and process.
* Then the MemoryTagManager can later be asked to check a
  memory range.

This is better because:
* We don't imply that range and manager are tied together.
* A slightly diferent range calculation for tag writing
  doesn't add more code to Process.
* Range checking code can now be unit tested.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D105630
2021-07-16 11:02:06 +01:00
Jonas Devlieghere 1e4a417ee6 [lldb] Always call DestroyImpl from Process::Finalize
Always destroy the process, regardless of its private state. This will
call the virtual function DoDestroy under the hood, giving our derived
class a chance to do the necessary tear down, including what to do when
the private state is eStateExited.

Differential revision: https://reviews.llvm.org/D106004
2021-07-14 13:35:53 -07:00
Jim Ingham 379f24ffde Revert "Revert "Reset the wakeup timeout when we re-enter the continue wait.""
This reverts commit 82a3883715.

The original version had a copy-paste error: using the Interrupt timeout
for the ResumeSynchronous wait, which is clearly wrong.  This error would
have been evident with real use, but the interrupt is long enough that it
only caused one testsuite failure (in the Swift fork).

Anyway, I found that mistake and fixed it and checked all the other places
where I had to plumb through a timeout, and added a test with a short
interrupt timeout stepping over a function that takes 3x the interrupt timeout
to complete, so that should detect a similar mistake in the future.
2021-07-12 14:20:49 -07:00
Med Ismail Bennani 8266b7ea7d [lldb/Target] Fix event handling during process launch
This patch fixes process event handling when the events are broadcasted
at launch. To do so, the patch introduces a new listener to fetch events
by hand off the event queue and then resending them ensure the event ordering.

Differental Revision: https://reviews.llvm.org/D105698

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-07-12 12:34:26 +01:00
Muhammad Omair Javaid 5e6aabd48e Support AArch64/Linux watchpoint on tagged addresses
AArch64 architecture support virtual addresses with some of the top bits ignored.
These ignored bits can host memory tags or bit masks that can serve to check for
authentication of address integrity. We need to clear away the top ignored bits
from watchpoint address to reliably hit and set watchpoints on addresses
containing tags or masks in their top bits.

This patch adds support to watch tagged addresses on AArch64/Linux.

Reviewed By: DavidSpickett

Differential Revision: https://reviews.llvm.org/D101361
2021-07-12 07:39:26 +05:00
Adrian Prantl d124133f17 Add scoped timers to ReadMemoryFromInferior and ReadMemoryFromFileCache. 2021-07-09 13:37:04 -07:00
Jonas Devlieghere fd2433e139 [lldb] Replace default bodies of special member functions with = default;
Replace default bodies of special member functions with = default;

$ run-clang-tidy.py -header-filter='lldb' -checks='-*,modernize-use-equals-default' -fix ,

https://clang.llvm.org/extra/clang-tidy/checks/modernize-use-equals-default.html

Differential revision: https://reviews.llvm.org/D104041
2021-07-02 11:31:16 -07:00
Jan Kratochvil e825c244b6 [lldb] Fix Recognizer/assert.test with glibc-2.33.9000-31.fc35.x86_64
While on regular Linux system (Fedora 34 GA, not updated):

* thread #1, name = '1', stop reason = hit program assert
    frame #0: 0x00007ffff7e242a2 libc.so.6`raise + 322
    frame #1: 0x00007ffff7e0d8a4 libc.so.6`abort + 278
    frame #2: 0x00007ffff7e0d789 libc.so.6`__assert_fail_base.cold + 15
    frame #3: 0x00007ffff7e1ca16 libc.so.6`__assert_fail + 70
  * frame #4: 0x00000000004011bd 1`main at assert.c:7:3

On Fedora 35 pre-release one gets:

* thread #1, name = '1', stop reason = signal SIGABRT
  * frame #0: 0x00007ffff7e48ee3 libc.so.6`pthread_kill@GLIBC_2.2.5 + 67
    frame #1: 0x00007ffff7dfb986 libc.so.6`raise + 22
    frame #2: 0x00007ffff7de5806 libc.so.6`abort + 230
    frame #3: 0x00007ffff7de571b libc.so.6`__assert_fail_base.cold + 15
    frame #4: 0x00007ffff7df4646 libc.so.6`__assert_fail + 70
    frame #5: 0x00000000004011bd 1`main at assert.c:7:3

I did not write a testcase as one needs the specific glibc. An
artificial test would just copy the changed source.

Reviewed By: mib

Differential Revision: https://reviews.llvm.org/D105133
2021-07-01 09:16:07 +02:00
Adrian Prantl 21e013303b Improve path remapping in cross-debugging scenarios
This patch implements a slight improvement when debugging across
platforms and remapping source paths that are in a non-native
format. See the unit test for examples.

rdar://79205675

Differential Revision: https://reviews.llvm.org/D104407
2021-06-29 15:27:01 -07:00
Adrian Prantl 302b1b9718 Express PathMappingList::FindFile() in terms of PathMappingList::RemapPath()
NFC.

This patch replaces the function body FindFile() with a call to
RemapPath(), since the two functions implement the same functionality.

Differential Revision: https://reviews.llvm.org/D104406
2021-06-29 15:14:31 -07:00
Adrian Prantl a346372200 Change PathMappingList::FindFile to return an optional result (NFC)
This is an NFC modernization refactoring that replaces the combination
of a bool return + reference argument, with an Optional return value.

Differential Revision: https://reviews.llvm.org/D104405
2021-06-29 15:10:46 -07:00
Adrian Prantl 4cf7c6c6a4 Change PathMappingList::RemapPath to return an optional result (NFC)
This is an NFC modernization refactoring that replaces the combination
of a bool return + reference argument, with an Optional return value.

Differential Revision: https://reviews.llvm.org/D104404
2021-06-25 14:15:29 -07:00
Martin Storsjö e50f9c419a [lldb] Rename StringRef _lower() method calls to _insensitive() 2021-06-25 00:22:01 +03:00
David Spickett 5d34362001 [lldb][AArch64] Add MTE memory tag reading to lldb
This adds GDB client support for the qMemTags packet
which reads memory tags. Following the design
which was recently committed to GDB.

https://sourceware.org/gdb/current/onlinedocs/gdb/General-Query-Packets.html#General-Query-Packets
(look for qMemTags)

lldb commands will use the new Process methods
GetMemoryTagManager and ReadMemoryTags.

The former takes a range and checks that:
* The current process architecture has an architecture plugin
* That plugin provides a MemoryTagManager
* That the range of memory requested lies in a tagged range
  (it will expand it to granules for you)

If all that was true you get a MemoryTagManager you
can give to ReadMemoryTags.

This two step process is done to allow commands to get the
tag manager without having to read tags as well. For example
you might just want to remove a logical tag, or error early
if a range with tagged addresses is inverted.

Note that getting a MemoryTagManager doesn't mean that the process
or a specific memory range is tagged. Those are seperate checks.
Having a tag manager just means this architecture *could* have
a tagging feature enabled.

An architecture plugin has been added for AArch64 which
will return a MemoryTagManagerAArch64MTE, which was added in a
previous patch.

Reviewed By: omjavaid

Differential Revision: https://reviews.llvm.org/D95602
2021-06-24 17:17:10 +01:00
Walter Erquinigo 2aa1dd1c66 [trace] Add a TraceCursor class
As a follow up of D103588, I'm reinitiating the discussion with a new proposal for traversing instructions in a trace which uses the feedback gotten in that diff.

See the embedded documentation in TraceCursor for more information. The idea is to offer an OOP way to traverse instructions exposing a minimal interface that makes no assumptions on:

- the number of instructions in the trace (i.e. having indices for instructions might be impractical for gigantic intel-pt traces, as it would require to decode the entire trace). This renders the use of indices to point to instructions impractical. Traces are big and expensive, and the consumer should try to do look linear lookups (forwards and/or backwards) and avoid random accesses (the API could be extended though, but for now I want to dicard that funcionality and leave the API extensible if needed).
- the way the instructions are represented internally by each Trace plug-in. They could be mmap'ed from a file, exist in plain vector or generated on the fly as the user requests the data.
- the actual data structure used internally for each plug-in. Ideas like having a struct TraceInstruction have been discarded because that would make the plug-in follow a certain data type, which might be costly. Instead, the user can ask the cursor for each independent property of the instruction it's pointing at.

The way to get a cursor is to ask Trace.h for the end or being cursor or a thread's trace.

There are some benefits of this approach:
- there's little cost to create a cursor, and this allows for lazily decoding a trace as the user requests data.
- each trace plug-in could decide how to cache the instructions it generates. For example, if a trace is small, it might decide to keep everything in memory, or if the trace is massive, it might decide to keep around the last thousands of instructions to speed up local searches.
- a cursor can outlive a stop point, which makes trace comparison for live processes feasible. An application of this is to compare profiling data of two runs of the same function, which should be doable with intel pt.

Differential Revision: https://reviews.llvm.org/D104422
2021-06-23 22:28:01 -07:00