3202 Commits

Author SHA1 Message Date
Michael Buch
134a94ae0b [lldb][test] TestCppTemplateArguments.py: skip on older compilers
This test needs to be compiled with compilers that support floating point NTTP.
2025-02-14 10:26:47 +00:00
Michael Buch
050933b41f [lldb][test] TestCppTemplateArguments.py: adjust expected type
LLVM started emitting the `DW_AT_const_value` for floating point template parameters since https://github.com/llvm/llvm-project/pull/127045. Adjust the expected type in this test. It's still not quite correct but that requires a separate fix in LLDB.
2025-02-13 23:13:46 +00:00
Jason Molenda
b666ac3b63
[lldb] Change lldb's breakpoint handling behavior, reland (#126988)
lldb today has two rules: When a thread stops at a BreakpointSite, we
set the thread's StopReason to be "breakpoint hit" (regardless if we've
actually hit the breakpoint, or if we've merely stopped *at* the
breakpoint instruction/point and haven't tripped it yet). And second,
when resuming a process, any thread sitting at a BreakpointSite is
silently stepped over the BreakpointSite -- because we've already
flagged the breakpoint hit when we stopped there originally.

In this patch, I change lldb to only set a thread's stop reason to
breakpoint-hit when we've actually executed the instruction/triggered
the breakpoint. When we resume, we only silently step past a
BreakpointSite that we've registered as hit. We preserve this state
across inferior function calls that the user may do while stopped, etc.

Also, when a user adds a new breakpoint at $pc while stopped, or changes
$pc to be the address of a BreakpointSite, we will silently step past
that breakpoint when the process resumes. This is purely a UX call, I
don't think there's any person who wants to set a breakpoint at $pc and
then hit it immediately on resuming.

One non-intuitive UX from this change, butt is necessary: If you're
stopped at a BreakpointSite that has not yet executed, you `stepi`, you
will hit the breakpoint and the pc will not yet advance. This thread has
not completed its stepi, and the ThreadPlanStepInstruction is still on
the stack. If you then `continue` the thread, lldb will now stop and
say, "instruction step completed", one instruction past the
BreakpointSite. You can continue a second time to resume execution.

The bugs driving this change are all from lldb dropping the real stop
reason for a thread and setting it to breakpoint-hit when that was not
the case. Jim hit one where we have an aarch64 watchpoint that triggers
one instruction before a BreakpointSite. On this arch we are notified of
the watchpoint hit after the instruction has been unrolled -- we disable
the watchpoint, instruction step, re-enable the watchpoint and collect
the new value. But now we're on a BreakpointSite so the watchpoint-hit
stop reason is lost.

Another was reported by ZequanWu in
https://discourse.llvm.org/t/lldb-unable-to-break-at-start/78282 we
attach to/launch a process with the pc at a BreakpointSite and
misbehave. Caroline Tice mentioned it is also a problem they've had with
putting a breakpoint on _dl_debug_state.

The change to each Process plugin that does execution control is that

1. If we've stopped at a BreakpointSite that has not been executed yet,
we will call Thread::SetThreadStoppedAtUnexecutedBP(pc) to record that.
When the thread resumes, if the pc is still at the same site, we will
continue, hit the breakpoint, and stop again.

2. When we've actually hit a breakpoint (enabled for this thread or
not), the Process plugin should call
Thread::SetThreadHitBreakpointSite(). When we go to resume the thread,
we will push a step-over-breakpoint ThreadPlan before resuming.

The biggest set of changes is to StopInfoMachException where we
translate a Mach Exception into a stop reason. The Mach exception codes
differ in a few places depending on the target (unambiguously), and I
didn't want to duplicate the new code for each target so I've tested
what mach exceptions we get for each action on each target, and
reorganized StopInfoMachException::CreateStopReasonWithMachException to
document these possible values, and handle them without specializing
based on the target arch.

I first landed this patch in July 2024 via
https://github.com/llvm/llvm-project/pull/96260

but the CI bots and wider testing found a number of test case failures
that needed to be updated, I reverted it. I've fixed all of those issues
in separate PRs and this change should run cleanly on all the CI bots
now.

rdar://123942164
2025-02-13 11:30:10 -08:00
John Harrison
c2e96778e0
[lldb-dap] Ensure we do not print the close sentinel when closing stdout. (#126833)
If you have an lldb-dap log file you'll almost always see a final
message like:

```
<-- 
Content-Length: 94

{
  "body": {
    "category": "stdout",
    "output": "\u0000\u0000"
  },
  "event": "output",
  "seq": 0,
  "type": "event"
}
<-- 
Content-Length: 94

{
  "body": {
    "category": "stderr",
    "output": "\u0000\u0000"
  },
  "event": "output",
  "seq": 0,
  "type": "event"
}
```

The OutputRedirect is always writing the `"\0"` byte as a final stdout
message during shutdown. Instead, I adjusted this to detect the sentinel
value and break out of the read loop as if we detected EOF.

---------

Co-authored-by: Pavel Labath <pavel@labath.sk>
2025-02-13 10:35:50 -08:00
Michael Buch
0feb00f17c [lldb][test] TestCPPEnumPromotion: make sure enums are preserved in dSYM
On macOS CI this was failing with:
```
FAIL: test_dsym (TestCPPEnumPromotion.TestCPPEnumPromotion)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 1784, in test_method
    return attrvalue(self)
  File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/lang/cpp/enum_promotion/TestCPPEnumPromotion.py", line 28, in test
    self.expect_expr("+EnumUChar::UChar", result_type=UChar_promoted.type.name)
  File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 2540, in expect_expr
    value_check.check_value(self, eval_result, str(eval_result))
  File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 299, in check_value
    test_base.assertSuccess(val.GetError())
  File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/packages/Python/lldbsuite/test/lldbtest.py", line 2575, in assertSuccess
    self.fail(self._formatMessage(msg, "'{}' is not success".format(error)))
AssertionError: 'error: <user expression 0>:1:2: use of undeclared identifier 'EnumUChar'
    1 | +EnumUChar::UChar
      |  ^
' is not success
```
But only for the `dSYM` variant of the test.

Looking at the dSYM, none of the enums are actually preserved in the debug-info. We have to actually use the enum types in source to get dsymutil to preserve them. This patch does just that.
2025-02-13 18:13:09 +00:00
Ilia Kuklin
f30c891464
[lldb] Analyze enum promotion type during parsing (#115005)
The information about an enum's best promotion type is discarded after
compilation and is not present in debug info. This patch repeats the
same analysis of each enum value as in the front-end to determine the
best promotion type during DWARF info parsing.

Fixes #86989
2025-02-13 22:08:31 +05:00
Georgiy Samoylov
1138a4964a
[lldb] Fix build problem in llgs tests for RISC-V (#127091)
During testing of LLDB on RISC-V target, tests from the llgs category
were built with an error: `Error when building test subject.`

```
llvm-project/lldb/test/API/tools/lldb-server/main.cpp:151:40: error: missing ')' after '__builtin_debugtrap'
  151 | #elif __has_builtin(__builtin_debugtrap())
      |                     ~~~~~~~~~~~~~~~~~~~^
llvm-project/lldb/test/API/tools/lldb-server/main.cpp:151:20: note: to match this '('
  151 | #elif __has_builtin(__builtin_debugtrap())
      |                    ^
```

This patch fixes this error.
2025-02-13 16:48:03 +00:00
Michael Buch
3ad8657ff6
[lldb][SBAPI] Add new SBType::GetTemplateParameterValue API (#126901)
This patch adds a new API to `SBType` to retrieve the value of a
template parameter given an index. We re-use the
`TypeSystemClang::GetIntegralTemplateArgument` for this and thus
currently only supports integral non-type template parameters. Types
like float/double are not supported yet.

rdar://144395216
2025-02-13 09:53:17 +00:00
Jason Molenda
cbb4e99f36
[lldb] Update ThreadPlanStepOut to handle new breakpoint behavior (#126838)
I will be changing breakpoint hitting behavior soon, where currently
lldb reports a breakpoint as being hit when a thread is *at* a
BreakpointSite, but possibly has not executed the breakpoint instruction
and trapped yet, to having lldb only report a breakpoint hit when the
breakpoint instruction has actually been executed.

One corner case bug with this change is that when you are stopped at a
breakpoint (that has been hit) on the last instruction of a function,
and you do `finish`, a ThreadPlanStepOut is pushed to the thread's plan
stack to put a breakpoint on the return address and resume execution.
And when the thread is asked to resume, it sees that it is at a
BreakpointSite that has been hit, and pushes a
ThreadPlanStepOverBreakpoint on the thread.   The StepOverBreakpoint
plan sees that the thread's state is eStateRunning (not eStateStepping),
so it marks itself as "auto continue" -- so once the breakpoint has
been stepped over, we will execution on the thread.

With current lldb stepping behavior ("a thread *at* a BreakpointSite is
said to have stopped with a breakpoint-hit stop reason, even if the
breakpoint hasn't been executed yet"),
`ThreadPlanStepOverBreakpoint::DoPlanExplainsStop` has a special bit of
code which detects when the thread stops with a eStopReasonBreakpoint.
It first checks if the pc is the same as when we started -- did our
"step instruction" not actually step? -- says the stop reason is
explained. Otherwise it sets auto-continue to false (because we've hit
an *unexpected* breakpoint, and we have advanced past our original pc,
and returns false - the stop reason is not explained.

So we do the "finish", lldb instruction steps, we stop *at* the
return-address breakpoint and lldb sets the thread's stop reason to
breakpoint-hit. ThreadPlanStepOverBreakpoint sees an
eStopReasonBreakpoint, sets its auto-continue to false, and says we
stopped for osme reason other than this plan. (and it will also report
`IsPlanStale()==true` so it will remove itself) Meanwhile the
ThreadPlanStepOut sees that it has stopped in the StackID it wanted to
run to, and return success.

This all changes when stopping at a breakpoint site doesn't report
breakpoint-hit until we actually execute the instruction. Now the
ThraedPlanStepOverBreakpoint looks at the thread's stop reason, it's
eStopReasonTrace (we've instruction stepped), and so it leaves its
auto-continue to `true`. ThreadPlanStepOut sees that it has reached its
goal StackID, removes its breakpoint, and says it is done.
Thread::ShouldStop thinks the auto-continue == yes vote from
ThreadPlanStepOverBreakpoint wins, and we lose control of the process.

This patch changes ThreadPlanStepOut to require that *both* (1) we are
at the StackID of the caller function, where we wanted to end up, and
(2) we have actually hit the breakpoint that we inserted.

This in effect means that now lldb instruction-steps over the breakpoint
in the callee function, stops at the return address of the caller
function. StepOverBreakpoint has completed. StepOut is still running,
and we continue the thread again. We immediatley hit the breakpoint
(that we're sitting at), and now ThreadPlanStepOut marks itself as
completed, and we return control to the user.

Jim suggests that ThreadPlanStepOverBreakpoint is a bit unusual because
it's not something pushed on the stack by a higher-order thread plan
that "owns" it, it is inserted by the Thread as it is about to resume,
if we're at a BreakpointSite. It has no connection to the thread plans
above it, but tries to set the auto-continue mode based on the state of
the thread when it is inserted (and tries to detect an unexpected
breakpoint and unset that auto-continue it previously decided on,
because it now realizes it should not influence execution control any
more). Instead maybe the
ThreadPlanStepOverBreakpoint should be inserted as a child plan of
whatever the lowest plan is on the stack at the point it is added.

I added an API test that will catch this bug in the new thread
breakpoint algorithm.
2025-02-12 13:48:01 -08:00
Jonas Devlieghere
d81b604656
[lldb] Add a test for terminal dimensions (#126598)
Add a test for the `term-width` and `term-height` settings. I thought I
was hitting bug because in my statusline test I was getting the default
values when running under PExpect. It turned out hat the issue is that
we clear the settings at the start of the test. The Editline tests
aren't affected by this because Editline provides its own functions to
get the terminal dimensions and explicitly does not rely on LLDB's
settings (presumably exactly because of this behavior).
2025-02-10 14:46:03 -08:00
Jonas Devlieghere
4722200773
[lldb] Merge TestSBCommandReturnObject tests
In #125132, Michael pointed out that there are now two tests with the
same name:

./lldb/test/API/api/command-return-object/TestSBCommandReturnObject.py
./lldb/test/API/python_api/commandreturnobject/TestSBCommandReturnObject.py
2025-02-09 11:16:59 -08:00
Felipe de Azevedo Piovezan
b8002933e9
[lldb] Add missing return statements in ThreadMemory (#126128)
These prevented ThreadMemory from correctly returning the
Name/Queue/Info of the backing thread.

Note about testing: this test only finds regressions if the system sets
a name or queue for the backing thread. While this may not be true
everywhere, it still provides coverage in some systems, e.g. in Apple
platforms.
2025-02-06 15:59:43 -08:00
Jason Molenda
8b65411b00
[lldb][NFC] Remove old skipIfOutOfTreeDebugserver's (#126144)
When a test depends on a new debugserver feature/fix, the API test must
be marked @skipIfOutOfTreeDebugserver because the macOS CI bots test
using the latest Xcode release debugserver. But over time all of these
fixes & new features are picked up in the Xcode debugserver and these
skips can be removed.

We may see unexpected test failures from removing all of these 1+ year
old skips, but that's likely a separate reason the test is failing that
is being papered over by this skip.
2025-02-06 14:50:09 -08:00
Ben Jackson
e8d437f827
[lldb] WatchAddress ignores modify option (#124847)
The WatchAddress API includes a flag to indicate if watchpoint should be
for read, modify or both. This API uses 2 booleans, but the 'modify'
flag was ignored and WatchAddress unconditionally watched write
(actually modify).

We now only watch for modify when the modify flag is true.

---

The included test fails prior to this patch and succeeds after. That is
previously specifying `False` for `modify` would still stop on _write_,
but after the patch correctly only stops on _read_
2025-02-04 16:03:13 -08:00
Jonas Devlieghere
53d6e59b59
[lldb] Check the command string in TestCommandInterepterPrintCallback
Now that we store the command in the CommandReturnObject (#125132) we
can check the command in the print callback.
2025-02-04 10:42:08 -08:00
Jonas Devlieghere
97f6e53386
[lldb] Support CommandInterpreter print callbacks (#125006)
Xcode uses a pseudoterminal for the debugger console.

- The upside of this apporach is that it means that it can rely on
LLDB's IOHandlers for multiline and script input.
- The downside of this approach is that the command output is printed to
the PTY and you don't get a SBCommandReturnObject. Adrian added support
for inline diagnostics (#110901) and we'd like to access those from the
IDE.

This patch adds support for registering a callback in the command
interpreter that gives access to the `(SB)CommandReturnObject` right
before it will be printed. The callback implementation can choose
whether it likes to handle printing the result or defer to lldb. If the
callback indicated it handled the result, the command interpreter will
skip printing the result.

We considered a few other alternatives to solve this problem:

- The most obvious one is using `HandleCommand`, which returns a
`SBCommandReturnObject`. The problem with this approach is the multiline
input mentioned above. We would need a way to tell the IDE that it
should expect multiline input, which isn't known until LLDB starts
handling the command.
- To address the multiline issue,we considered exposing (some of the)
IOHandler machinery through the SB API. To solve this particular issue,
that would require reimplementing a ton of logic that already exists
today in the CommandInterpeter. Furthermore that seems like overkill
compared to the proposed solution.

rdar://141254310
2025-02-04 09:01:08 -08:00
Jonas Devlieghere
906eeeda83
[lldb] Store the command in the CommandReturnObject (#125132)
As suggested in #125006. Depending on which PR lands first, I'll update
`TestCommandInterepterPrintCallback.py` to check that the
`CommandReturnObject` passed to the callback has the correct command.
2025-02-04 08:55:30 -08:00
Jacob Lalonde
ce7bca7691
[LLDB][Save Core Options] Custom ranges should follow the same safety checks as everyone else (#125323)
I encountered a `qMemoryRegionInfo not supported` error when capturing a
Minidump. This was surprising, and I started looking around I found
@jasonmolenda's fix in #115963 and then realized I was not validated
anything from the custom ranges.
2025-02-03 19:22:01 -08:00
Adrian Vogelsgesang
8e6fa15bc3
[lldb-dap] Support column breakpoints (#125347)
This commit adds support for column breakpoints to lldb-dap

To do so, support for the `breakpointLocations` request was
added. To find all available breakpoint positions, we iterate over
the line table.

The `setBreakpoints` request already forwarded the column correctly to
`SBTarget::BreakpointCreateByLocation`. However, `SourceBreakpointMap`
did not keep track of multiple breakpoints in the same line. To do so,
the `SourceBreakpointMap` is now indexed by line+column instead of by
line only.

This was previously submitted as #113787, but got reverted due to
failures on ARM and macOS. This second attempt has less strict test
case expectations. Also, I added a release note.
2025-02-04 01:23:28 +01:00
Ben Jackson
c26bb4f095
[lldb] correct event when removing all watchpoints (#125312)
LLDB: correct event when removing all watchpoints
    
    Previously we incorrectly checked for a "breakpoint changed" event
    listener removing all watchpoints (e.g. via
SBTarget::DeleteAllWatchpoints()), although we would emit a "watchpoint
    changed" event if there were a listener for 'breakpoint changed'.
    
This meant that we might not emit a "watchpoint changed" event if there
    was a listener for this event.
    
    Correct it to check for the "watchpoint changed" event.


---


Updated regression tests which were also incorrectly peeking for the
wrong event type. The 'remove' action actually triggers 2 events which
the test didn't allow, so I updated it to allow specifically what was
requested.

The test fails (expectedly) at the line following "DeleteAllWatchpoints"
prior to this patch, and passes after.
2025-02-03 14:39:43 -08:00
Zequan Wu
e269c2b5fa
[lldb] Show value for libcxx and libstdcxx summary and remove pointer value in libcxx container summary (#125294)
This has two changes:
1. Set show value for libcxx and libstdcxx summary provider. This will
print the pointer value for both pointer type and reference type.
2. Remove pointer value printing in libcxx container summary.

Discussion:

https://discourse.llvm.org/t/lldb-hides-raw-pointer-value-for-libcxx-and-libstdcxx-pointer-types-in-summary-string/84226
2025-02-03 14:34:20 -05:00
Jonas Devlieghere
6deee0d5b3
[lldb] Use llvm::Error instead of CommandReturnObject for error reporting (#125125)
Use `llvm::Error` instead of `CommandReturnObject` for error reporting.
The command return objects were populated with errors but never
displayed. With this patch they're at least logged.
2025-01-31 13:23:26 -08:00
Adrian Prantl
87b7f63a11 Revert "Reland "[lldb] Implement basic support for reverse-continue" (#125242)"
This reverts commit 7e66cf74fb4e6a103f923e34700a7b6f20ac2a9b.

Breaking green dragon:

https://green.lab.llvm.org/job/llvm.org/view/LLDB/job/as-lldb-cmake/19569/testReport/junit/lldb-api/functionalities_reverse-execution/TestReverseContinueWatchpoints_py/
2025-01-31 13:11:20 -08:00
Jonas Devlieghere
dbabad0fc0
[lldb] Use validation combination of options in TestAbbreviations (#125270)
Name and line number are part of different option groups and are not
compatible.

```
(lldb) breakpoint set -n foo -l 10
error: invalid combination of options for the given command
```

The help output for `breakpoint set` confirms this. This patch updates
the test to use two compatible options. With the improved error
reporting from #125125 this becomes an issue.
2025-01-31 11:57:49 -08:00
David Spickett
7e66cf74fb
Reland "[lldb] Implement basic support for reverse-continue" (#125242)
This reverts commit a774de807e56c1147d4630bfec3110c11d41776e.

This is the same changes as last time, plus:
* We load the binary into the target object so that on Windows, we can
resolve the locations of the functions.
* We now assert that each required breakpoint has at least 1 location,
to prevent an issue like that in the future.
* We are less strict about the unsupported error message, because it
prints "error: windows" on Windows instead of "error: gdb-remote".
2025-01-31 15:56:33 +00:00
Pavel Labath
13d0318a98
[lldb] Add support for gdb-style 'x' packet (#124733)
See also
https://discourse.llvm.org/t/rfc-fixing-incompatibilties-of-the-x-packet-w-r-t-gdb/84288
and https://sourceware.org/pipermail/gdb/2025-January/051705.html
2025-01-31 09:07:11 +01:00
David Spickett
a774de807e
Revert "Reland "[lldb] Implement basic support for reverse-continue" (#123906)"" (#125091)
Reverts llvm/llvm-project#123945

Has failed on the Windows on Arm buildbot:
https://lab.llvm.org/buildbot/#/builders/141/builds/5865
```
********************
Unresolved Tests (2):
  lldb-api :: functionalities/reverse-execution/TestReverseContinueBreakpoints.py
  lldb-api :: functionalities/reverse-execution/TestReverseContinueWatchpoints.py
********************
Failed Tests (1):
  lldb-api :: functionalities/reverse-execution/TestReverseContinueNotSupported.py
```
Reverting while I reproduce locally.
2025-01-30 16:45:36 +00:00
David Spickett
0caba6c8dc
Reland "[lldb] Implement basic support for reverse-continue" (#123906)" (#123945)
This reverts commit 22561cfb443267905d4190f0e2a738e6b412457f and fixes
b7b9ccf44988edf49886743ae5c3cf4184db211f (#112079).

The problem is that x86_64 and Arm 32-bit have memory regions above the
stack that are readable but not writeable. First Arm:
```
(lldb) memory region --all
<...>
[0x00000000fffcf000-0x00000000ffff0000) rw- [stack]
[0x00000000ffff0000-0x00000000ffff1000) r-x [vectors]
[0x00000000ffff1000-0xffffffffffffffff) ---
```
Then x86_64:
```
$ cat /proc/self/maps
<...>
7ffdcd148000-7ffdcd16a000 rw-p 00000000 00:00 0                          [stack]
7ffdcd193000-7ffdcd196000 r--p 00000000 00:00 0                          [vvar]
7ffdcd196000-7ffdcd197000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0                  [vsyscall]
```
Compare this to AArch64 where the test did pass:
```
$ cat /proc/self/maps
<...>
ffffb87dc000-ffffb87dd000 r--p 00000000 00:00 0                          [vvar]
ffffb87dd000-ffffb87de000 r-xp 00000000 00:00 0                          [vdso]
ffffb87de000-ffffb87e0000 r--p 0002a000 00:3c 76927217                   /usr/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1
ffffb87e0000-ffffb87e2000 rw-p 0002c000 00:3c 76927217                   /usr/lib/aarch64-linux-gnu/ld-linux-aarch64.so.1
fffff4216000-fffff4237000 rw-p 00000000 00:00 0                          [stack]
```
To solve this, look up the memory region of the stack pointer (using
https://lldb.llvm.org/resources/lldbgdbremote.html#qmemoryregioninfo-addr)
and constrain the read to within that region. Since we know the stack is
all readable and writeable.

I have also added skipIfRemote to the tests, since getting them working
in that context is too complex to be worth it.

Memory write failures now display the range they tried to write, and
register write errors will show the name of the register where possible.

The patch also includes a workaround for a an issue where the test code
could mistake an `x` response that happens to begin with an `O` for an
output packet (stdout). This workaround will not be necessary one we
start using the [new
implementation](https://discourse.llvm.org/t/rfc-fixing-incompatibilties-of-the-x-packet-w-r-t-gdb/84288)
of the `x` packet.

---------

Co-authored-by: Pavel Labath <pavel@labath.sk>
2025-01-30 14:03:01 +00:00
David Spickett
c5840cc609
[lldb][AArch64] Add register fields for Guarded Control Stack registers (#124295)
The features and locked registers hold the same bits, the latter
is a lock for the former. Tested with core files and live processes.

I thought about setting a non-zero lock register in the core file,
however:
* We can be pretty sure it's reading correctly because its between
  the 2 other GCS registers in the same core file note.
* I can't make the test case modify lock bits because userspace
can't clear them (without using ptrace) and we don't know what the libc
has locked
  (probably all feature bits).
2025-01-28 12:05:24 +00:00
David Spickett
75aa5a3556
[lldb][AArch64] Add Guarded Control Stack support for Linux core files (#124293)
This allows you to read the same registers as you would for a live
process.

As the content of proc/pid/smaps is not included in the core file, we
don't get the "ss" marker that tell us that it is shadow stack. The GCS
region is still in the list though.
2025-01-28 11:32:24 +00:00
David Spickett
e9e06bea86 [lldb][AArch64][NFC] Move a comment in GCS tests
Got put in the wrong place during a rebase.
2025-01-27 13:27:31 +00:00
David Spickett
b31e9747d0
[lldb][AArch64] Fix expression evaluation with Guarded Control Stacks (#123918)
When the Guarded Control Stack (GCS) is enabled, returns cause the
processor to validate that the address at the location pointed to by
gcspr_el0 matches the one in the link register.

```
ret (lr=A) << pc

| GCS |
+=====+
|  A  |
|  B  | << gcspr_el0

Fault: tried to return to A when you should have returned to B.
```

Therefore when an expression wrapper function tries to return to the
expression return address (usually `_start` if there is a libc), it
would fault.

```
ret (lr=_start) << pc

| GCS        |
+============+
| user_func1 |
| user_func2 | << gcspr_el0

Fault: tried to return to _start when you should have returned to user_func2.
```

To fix this we must push that return address to the GCS in
PrepareTrivialCall. This value is then consumed by the final return and
the expression completes as expected.

If for some reason that fails, we will manually restore the value of
gcspr_el0, because it turns out that PrepareTrivialCall
does not restore registers if it fails at all. So for now I am handling
gcspr_el0 specifically, but I have filed
https://github.com/llvm/llvm-project/issues/124269 to address the
general problem.

(the other things PrepareTrivialCall does are exceedingly likely to not
fail, so we have never noticed this)

```
ret (lr=_start) << pc

| GCS        |
+============+
| user_func1 |
| user_func2 |
| _start     | << gcspr_el0

No fault, we return to _start as normal.
```

The gcspr_el0 register will be restored after expression evaluation so
that the program can continue correctly.

However, due to restrictions in the Linux GCS ABI, we will not restore
the enable bit of gcs_features_enabled. Re-enabling GCS via ptrace is
not supported because it requires memory to be allocated by the kernel.

We could disable GCS if the expression enabled GCS, however this would
use up that state transition that the program might later rely on. And
generally it is cleaner to ignore the enable bit, rather than one state
transition of it.

We will also not restore the GCS entry that was overwritten with the
expression's return address. On the grounds that:
* This entry will never be used by the program. If the program branches,
the entry will be overwritten. If the program returns, gcspr_el0 will
point to the entry before the expression return address and that entry
will instead be validated.
* Any expression that calls functions will overwrite even more entries,
so the user needs to be aware of that anyway if they want to preserve
the contents of the GCS for inspection.
* An expression could leave the program in a state where restoring the
value makes the situation worse. Especially if we ever support this in
bare metal debugging.

I will later document all this on
https://lldb.llvm.org/use/aarch64-linux.html.

Tests have been added for:
* A function call that does not interact with GCS.
* A call that does, and disables it (we do not re-enable it).
* A call that does, and enables it (we do not disable it again).
* Failure to push an entry to the GCS stack.
2025-01-27 13:06:33 +00:00
Dave Lee
aba0476f23 [lldb] Delete lldbutil.PrintableRegex (NFC)
Use of this class wasn't making use of the original regex string. Note that `re.Pattern`
has a `pattern` property to access the original regex.
2025-01-25 09:58:52 -08:00
Dave Lee
8b62114727 [lldb] Delete unused lldbutil.print_registers (NFC) 2025-01-25 09:39:10 -08:00
Dave Lee
7293455cf2
[lldb] Add SBThread.selected_frame property (#123981)
Adds a `selected_frame` property to `SBThread`. The setter accepts either a frame index (like `SetSelectedFrame`), or a frame object.

Updates a few tests to make use of the new `selected_frame`. While doing so I noticed some of the usage could be cleaned up, so I did that too.
2025-01-24 10:02:15 -08:00
David Spickett
02c6002d1c
[lldb][AArch64] Add Guarded Control Stack registers (#123720)
The Guarded Control Stack extension implements a shadow stack and the
Linux kernel provides access to 3 registers for it via ptrace.

struct user_gcs {
	__u64 features_enabled;
	__u64 features_locked;
	__u64 gcspr_el0;
};

This commit adds support for reading those from a live process.

The first 2 are pseudo registers based on the real control register and
the 3rd is a real register. This is the stack pointer for the guarded
stack.

I have added a "gcs_" prefix to the "features" registers so that they
have a clear name when shown individually. Also this means they will tab
complete from "gcs", and be next to gcspr_el0 in any sorted lists of
registers.

Guarded Control Stack Registers:
  gcs_features_enabled = 0x0000000000000000
  gcs_features_locked = 0x0000000000000000
  gcspr_el0 = 0x0000000000000000

Testing is more of the usual, where possible I'm writing a register then
doing something in the program to confirm the value was actually sent to
ptrace.
2025-01-24 13:42:06 +00:00
Pavel Labath
0236cb6895
[lldb] Enable "frame diagnose" on linux (#123217)
.. by changing the signal stop reason format 🤦

The reason this did not work is because the code in
`StopInfo::GetCrashingDereference` was looking for the string "address="
to extract the address of the crash. Macos stop reason strings have the
form
```
  EXC_BAD_ACCESS (code=1, address=0xdead)
```
while on linux they look like:
```
  signal SIGSEGV: address not mapped to object (fault address: 0xdead)
```

Extracting the address from a string sounds like a bad idea, but I
suppose there's some value in using a consistent format across
platforms, so this patch changes the signal format to use the equals
sign as well. All of the diagnose tests pass except one, which appears
to fail due to something similar #115453 (disassembler reports
unrelocated call targets).

I've left the tests disabled on windows, as the stop reason reporting
code works very differently there, and I suspect it won't work out of
the box. If I'm wrong -- the XFAIL will let us know.
2025-01-23 13:04:36 +01:00
Michael Buch
4bcdb26dac
Revert "[lldb][test] Remove compiler version check and use regex" (#124101)
Reverts llvm/llvm-project#123393

This is causing `TestVectorOfVectorsFromStdModule.py` to fail on the the
macOS clang-15 matrix bot.
2025-01-23 11:29:06 +00:00
Jacob Lalonde
a939a9fd53
[LLDB-DAP] Send Progress update message over DAP (#123837)
When testing my SBProgress DAP PR (#123826), I noticed Progress update
messages aren't sent over DAP. This patch adds the lldb progress event's
message to the body when sent over DAP.

Before 

![image](https://github.com/user-attachments/assets/404adaa8-b784-4f23-895f-cd3625fdafad)


Now

![image](https://github.com/user-attachments/assets/eb1c3235-0936-4e36-96e5-0a0ee60dabb8)

Tested with my [progress tester
command](https://gist.github.com/Jlalond/48d85e75a91f7a137e3142e6a13d0947),
testing 10 events 5 seconds apart 1-10
2025-01-22 15:49:13 -08:00
Pavel Labath
22561cfb44
Revert "[lldb] Implement basic support for reverse-continue" (#123906)
Reverts llvm/llvm-project#112079 due to failures on the arm bot.
2025-01-22 09:43:11 +01:00
Robert O'Callahan
b7b9ccf449
[lldb] Implement basic support for reverse-continue (#112079)
This commit adds support for a
`SBProcess::ContinueInDirection()` API. A user-accessible command for
this will follow in a later commit.

This feature depends on a gdbserver implementation (e.g. `rr`) providing
support for the `bc` and `bs` packets. `lldb-server` does not support
those packets, and there is no plan to change that. For testing
purposes, this commit adds a Python implementation of *very limited*
record-and-reverse-execute functionality, implemented as a proxy between
lldb and lldb-server in `lldbreverse.py`. This should not (and in
practice cannot) be used for anything except testing.

The tests here are quite minimal but we test that simple breakpoints and
watchpoints work as expected during reverse execution, and that
conditional breakpoints and watchpoints work when the condition calls a
function that must be executed in the forward direction.
2025-01-22 08:37:17 +01:00
Jonas Devlieghere
2841cdbfda
[lldb] Support format string in the prompt (#123430)
Implement ansi::StripAnsiTerminalCodes and fix a long standing bug where
using format strings in lldb's prompt resulted in an incorrect prompt
column width.
2025-01-21 21:01:02 -08:00
David Spickett
5658bc4ae7
[lldb][Linux] Add Control Protection Fault signal (#122917)
This will be sent by Arm's Guarded Control Stack extension when an
invalid return is executed.

The signal does have an address we could show, but it's the PC at which
the fault occured. The debugger has plenty of ways to show you that
already, so I've left it out.

```
(lldb) c
Process 460 resuming
Process 460 stopped
* thread #1, name = 'test', stop reason = signal SIGSEGV: control protection fault
    frame #0: 0x0000000000400784 test`main at main.c:57:1
   54  	  afunc();
   55  	  printf("return from main\n");
   56  	  return 0;
-> 57  	}
(lldb) dis
<...>
->  0x400784 <+100>: ret
```

The new test case generates the signal by corrupting the link register
then attempting to return. This will work whether we manually enable GCS
or the C library does it for us.

(in the former case you could just return from main and it would fault)
2025-01-21 09:24:41 +00:00
Wanyi
b62e55803c
[lldb][test] Remove compiler version check and use regex (#123393)
The test checks specific compiler version to determine the output.
However, the compiler version string is always set to 15.0.0 for our
local build. Remove this check and use regex match instead.

## Test Plan
```
./bin/llvm-lit -sva /home/wanyi/llvm-sand/external/llvm-project/lldb/test/API/commands/expression/import-std-module/vector-of-vectors/TestVectorOfVectorsFromStdModule.py
...
Skipping the following test categories: ['dsym', 'gmodules', 'debugserver', 'objc']

--
Command Output (stderr):
--
UNSUPPORTED: LLDB (/home/wanyi/llvm-sand/build/Release+Distribution/fbcode-x86_64/toolchain/bin/clang-x86_64) :: test_dsym (TestVectorOfVectorsFromStdModule.TestVectorOfVectors) (test case does not fall in any category of interest for this run) 
PASS: LLDB (/home/wanyi/llvm-sand/build/Release+Distribution/fbcode-x86_64/toolchain/bin/clang-x86_64) :: test_dwarf (TestVectorOfVectorsFromStdModule.TestVectorOfVectors)
PASS: LLDB (/home/wanyi/llvm-sand/build/Release+Distribution/fbcode-x86_64/toolchain/bin/clang-x86_64) :: test_dwo (TestVectorOfVectorsFromStdModule.TestVectorOfVectors)
----------------------------------------------------------------------
Ran 3 tests in 4.636s

OK (skipped=1)

--

********************

Testing Time: 4.97s

Total Discovered Tests: 1
  Passed: 1 (100.00%)
```
2025-01-17 22:27:34 -05:00
Adrian Prantl
8f18f36b49 [lldb] Skip unreliable test under ASAN 2025-01-17 13:27:11 -08:00
Jacob Lalonde
6b048aeaf8
[LLDB] Add SBProgress so Python scripts can also report progress (#119052)
Recently I've been working on a lot of internal Python tooling, and in
certain cases I want to report async to the script over DAP. Progress.h
already handles this, so I've exposed Progress via the SB API so Python
scripts can also update progress objects.

I actually have no idea how to test this, so I just wrote a [toy command
to test
it](https://gist.github.com/Jlalond/48d85e75a91f7a137e3142e6a13d0947)


![image](https://github.com/user-attachments/assets/7317cbb8-9145-4fdb-bacf-9864bf50c467)

I also copied the first section of the extensive Progress.h class
documentation to the docstrings.
2025-01-17 12:00:31 -08:00
Pavel Labath
58fc8029e9 [lldb] Skip TestStepUntilAPI on !x86_64, !aarch64
The compiler does not support this feature on other architectures.
2025-01-17 13:07:06 +01:00
Pavel Labath
f66a5e220c
[lldb] Fix SBThread::StepOverUntil for discontinuous functions (#123046)
I think the only issue here was that we would erroneously consider
functions which are "in the middle" of the function were stepping to as
a part of the function, and would try to step into them (likely stepping
out of the function instead) instead of giving up early.
2025-01-17 12:13:30 +01:00
Jonas Devlieghere
8ac0aaaebb
[lldb] Improve user expression diagnostics (#123242)
This patch rewords some of the user expression diagnostics.

 - Differentiate between being interrupted and hitting a breakpoint.
- Use "expression execution" to make it more obvious that the diagnostic
is associated with the user expression.
 - Consistently use a colon instead of semicolons and commas.

rdar://143059974
2025-01-16 16:09:20 -08:00
Felipe de Azevedo Piovezan
cb82771c96
[lldb] Add OS plugin property for reporting all threads (#123145)
Currently, an LLDB target option controls whether plugins report all
threads. However, it seems natural for this knowledge could come from
the plugin itself. To support this, this commits adds a virtual method
to the plugin base class, making the Python OS query the target option
to preserve existing behavior.
2025-01-16 15:05:46 -08:00