<feed xmlns='http://www.w3.org/2005/Atom'>
<title>llvm-project.git/lldb/source/Target/ThreadPlanStepOut.cpp, branch users/mingmingl-llvm/samplefdo-profile-format</title>
<subtitle>Unnamed repository; edit this file 'description' to name the repository.
</subtitle>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/'/>
<entry>
<title>[lldb] Create ThreadPlanStepOut ctor that never skips frames (#136163)</title>
<updated>2025-04-17T21:13:28+00:00</updated>
<author>
<name>Felipe de Azevedo Piovezan</name>
<email>fpiovezan@apple.com</email>
</author>
<published>2025-04-17T21:13:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=12becfff035a33141a0b2fb3ea5d5558738ce7eb'/>
<id>12becfff035a33141a0b2fb3ea5d5558738ce7eb</id>
<content type='text'>
The function QueueThreadPlanForStepOutNoShouldStop has the semantics of
"go this parent frame"; ThreadPlanStepOut needs to respect that, not
skipping over any frames it finds uninteresting. This commit creates a
constructor that respects such instruction.</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The function QueueThreadPlanForStepOutNoShouldStop has the semantics of
"go this parent frame"; ThreadPlanStepOut needs to respect that, not
skipping over any frames it finds uninteresting. This commit creates a
constructor that respects such instruction.</pre>
</div>
</content>
</entry>
<entry>
<title>[lldb][nfc] Split the constructor of ThreadPlanStepOut (#136160)</title>
<updated>2025-04-17T19:53:25+00:00</updated>
<author>
<name>Felipe de Azevedo Piovezan</name>
<email>fpiovezan@apple.com</email>
</author>
<published>2025-04-17T19:53:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=9f9c1f93819d441c561d18a73a55bcb6d8a692df'/>
<id>9f9c1f93819d441c561d18a73a55bcb6d8a692df</id>
<content type='text'>
A subsequent commit will create a new constructor for ThreadPlanStepOut,
which needs to reuse much of the same logic of the existing constructor.
This commit places all of that reusable logic into a separate function.</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
A subsequent commit will create a new constructor for ThreadPlanStepOut,
which needs to reuse much of the same logic of the existing constructor.
This commit places all of that reusable logic into a separate function.</pre>
</div>
</content>
</entry>
<entry>
<title>[lldb][nfc] Factor out code from ThreadPlanStepOut ctor (#136159)</title>
<updated>2025-04-17T18:33:07+00:00</updated>
<author>
<name>Felipe de Azevedo Piovezan</name>
<email>fpiovezan@apple.com</email>
</author>
<published>2025-04-17T18:33:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=9d5f16308a2a1d778b9022c3a06a3cecc6d5e066'/>
<id>9d5f16308a2a1d778b9022c3a06a3cecc6d5e066</id>
<content type='text'>
A future patch will need to create a new constructor for this class, and
extracting code out of its sole existing constructor will make this
easier.

This commit creates a helper function for the code computing the target
frame to step out to.</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
A future patch will need to create a new constructor for this class, and
extracting code out of its sole existing constructor will make this
easier.

This commit creates a helper function for the code computing the target
frame to step out to.</pre>
</div>
</content>
</entry>
<entry>
<title>[lldb] inserted a typeo when checking in a suggested fix</title>
<updated>2025-02-12T22:00:41+00:00</updated>
<author>
<name>Jason Molenda</name>
<email>jmolenda@apple.com</email>
</author>
<published>2025-02-12T22:00:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=fa71238da800f3a818ec0e0649462389dc577890'/>
<id>fa71238da800f3a818ec0e0649462389dc577890</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>[lldb] Update ThreadPlanStepOut to handle new breakpoint behavior (#126838)</title>
<updated>2025-02-12T21:48:01+00:00</updated>
<author>
<name>Jason Molenda</name>
<email>jmolenda@apple.com</email>
</author>
<published>2025-02-12T21:48:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=cbb4e99f3613549c2168f52d6f348e3a7ee3cf55'/>
<id>cbb4e99f3613549c2168f52d6f348e3a7ee3cf55</id>
<content type='text'>
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.</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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.</pre>
</div>
</content>
</entry>
<entry>
<title>[lldb] Move ValueObject into its own library (NFC) (#113393)</title>
<updated>2024-10-25T03:20:48+00:00</updated>
<author>
<name>Jonas Devlieghere</name>
<email>jonas@devlieghere.com</email>
</author>
<published>2024-10-25T03:20:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=b852fb1ec5fa15f0b913cc4988cbd09239b19904'/>
<id>b852fb1ec5fa15f0b913cc4988cbd09239b19904</id>
<content type='text'>
ValueObject is part of lldbCore for historical reasons, but conceptually
it deserves to be its own library. This does introduce a (link-time) circular
dependency between lldbCore and lldbValueObject, which is unfortunate
but probably unavoidable because so many things in LLDB rely on
ValueObject. We already have cycles and these libraries are never built
as dylibs so while this doesn't improve the situation, it also doesn't
make things worse.

The header includes were updated with the following command:

```
find . -type f -exec sed -i.bak "s%include \"lldb/Core/ValueObject%include \"lldb/ValueObject/ValueObject%" '{}' \;
```</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
ValueObject is part of lldbCore for historical reasons, but conceptually
it deserves to be its own library. This does introduce a (link-time) circular
dependency between lldbCore and lldbValueObject, which is unfortunate
but probably unavoidable because so many things in LLDB rely on
ValueObject. We already have cycles and these libraries are never built
as dylibs so while this doesn't improve the situation, it also doesn't
make things worse.

The header includes were updated with the following command:

```
find . -type f -exec sed -i.bak "s%include \"lldb/Core/ValueObject%include \"lldb/ValueObject/ValueObject%" '{}' \;
```</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "Revert "[lldb] Extend frame recognizers to hide frames from backtraces (#104523)""</title>
<updated>2024-08-23T18:06:01+00:00</updated>
<author>
<name>Adrian Prantl</name>
<email>aprantl@apple.com</email>
</author>
<published>2024-08-23T16:55:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=3c0fba4f2471cacb27d787c7d8f54f21d9dcafae'/>
<id>3c0fba4f2471cacb27d787c7d8f54f21d9dcafae</id>
<content type='text'>
This reverts commit 547917aebd1e79a8929b53f0ddf3b5185ee4df74.
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 547917aebd1e79a8929b53f0ddf3b5185ee4df74.
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "[lldb] Extend frame recognizers to hide frames from backtraces (#104523)"</title>
<updated>2024-08-22T11:24:57+00:00</updated>
<author>
<name>Dmitri Gribenko</name>
<email>gribozavr@gmail.com</email>
</author>
<published>2024-08-22T09:58:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=547917aebd1e79a8929b53f0ddf3b5185ee4df74'/>
<id>547917aebd1e79a8929b53f0ddf3b5185ee4df74</id>
<content type='text'>
This reverts commit f01f80ce6ca7640bb0e267b84b1ed0e89b57e2d9.

This commit introduces an msan violation. See the discussion on https://github.com/llvm/llvm-project/pull/104523.
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit f01f80ce6ca7640bb0e267b84b1ed0e89b57e2d9.

This commit introduces an msan violation. See the discussion on https://github.com/llvm/llvm-project/pull/104523.
</pre>
</div>
</content>
</entry>
<entry>
<title>[lldb] Extend frame recognizers to hide frames from backtraces (#104523)</title>
<updated>2024-08-20T23:01:22+00:00</updated>
<author>
<name>Adrian Prantl</name>
<email>aprantl@apple.com</email>
</author>
<published>2024-08-20T23:01:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=f01f80ce6ca7640bb0e267b84b1ed0e89b57e2d9'/>
<id>f01f80ce6ca7640bb0e267b84b1ed0e89b57e2d9</id>
<content type='text'>
Compilers and language runtimes often use helper functions that are
fundamentally uninteresting when debugging anything but the
compiler/runtime itself. This patch introduces a user-extensible
mechanism that allows for these frames to be hidden from backtraces and
automatically skipped over when navigating the stack with `up` and
`down`.

This does not affect the numbering of frames, so `f &lt;N&gt;` will still
provide access to the hidden frames. The `bt` output will also print a
hint that frames have been hidden.

My primary motivation for this feature is to hide thunks in the Swift
programming language, but I'm including an example recognizer for
`std::function::operator()` that I wished for myself many times while
debugging LLDB.

rdar://126629381


Example output. (Yes, my proof-of-concept recognizer could hide even
more frames if we had a method that returned the function name without
the return type or I used something that isn't based off regex, but it's
really only meant as an example).

before:
```
(lldb) thread backtrace --filtered=false
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
    frame #1: 0x0000000100003a00 a.out`decltype(std::declval&lt;int (*&amp;)(int, int)&gt;()(std::declval&lt;int&gt;(), std::declval&lt;int&gt;())) std::__1::__invoke[abi:se200000]&lt;int (*&amp;)(int, int), int, int&gt;(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
    frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper&lt;int, false&gt;::__call[abi:se200000]&lt;int (*&amp;)(int, int), int, int&gt;(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
    frame #3: 0x0000000100003968 a.out`std::__1::__function::__alloc_func&lt;int (*)(int, int), std::__1::allocator&lt;int (*)(int, int)&gt;, int (int, int)&gt;::operator()[abi:se200000](this=0x000000016fdff280, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:171:12
    frame #4: 0x00000001000026bc a.out`std::__1::__function::__func&lt;int (*)(int, int), std::__1::allocator&lt;int (*)(int, int)&gt;, int (int, int)&gt;::operator()(this=0x000000016fdff278, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:313:10
    frame #5: 0x0000000100003c38 a.out`std::__1::__function::__value_func&lt;int (int, int)&gt;::operator()[abi:se200000](this=0x000000016fdff278, __args=0x000000016fdff224, __args=0x000000016fdff220) const at function.h:430:12
    frame #6: 0x0000000100002038 a.out`std::__1::function&lt;int (int, int)&gt;::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
    frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
    frame #8: 0x0000000183cdf154 dyld`start + 2476
(lldb) 
```

after

```
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
    frame #1: 0x0000000100003a00 a.out`decltype(std::declval&lt;int (*&amp;)(int, int)&gt;()(std::declval&lt;int&gt;(), std::declval&lt;int&gt;())) std::__1::__invoke[abi:se200000]&lt;int (*&amp;)(int, int), int, int&gt;(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
    frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper&lt;int, false&gt;::__call[abi:se200000]&lt;int (*&amp;)(int, int), int, int&gt;(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
    frame #6: 0x0000000100002038 a.out`std::__1::function&lt;int (int, int)&gt;::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
    frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
    frame #8: 0x0000000183cdf154 dyld`start + 2476
Note: Some frames were hidden by frame recognizers
```</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Compilers and language runtimes often use helper functions that are
fundamentally uninteresting when debugging anything but the
compiler/runtime itself. This patch introduces a user-extensible
mechanism that allows for these frames to be hidden from backtraces and
automatically skipped over when navigating the stack with `up` and
`down`.

This does not affect the numbering of frames, so `f &lt;N&gt;` will still
provide access to the hidden frames. The `bt` output will also print a
hint that frames have been hidden.

My primary motivation for this feature is to hide thunks in the Swift
programming language, but I'm including an example recognizer for
`std::function::operator()` that I wished for myself many times while
debugging LLDB.

rdar://126629381


Example output. (Yes, my proof-of-concept recognizer could hide even
more frames if we had a method that returned the function name without
the return type or I used something that isn't based off regex, but it's
really only meant as an example).

before:
```
(lldb) thread backtrace --filtered=false
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
    frame #1: 0x0000000100003a00 a.out`decltype(std::declval&lt;int (*&amp;)(int, int)&gt;()(std::declval&lt;int&gt;(), std::declval&lt;int&gt;())) std::__1::__invoke[abi:se200000]&lt;int (*&amp;)(int, int), int, int&gt;(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
    frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper&lt;int, false&gt;::__call[abi:se200000]&lt;int (*&amp;)(int, int), int, int&gt;(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
    frame #3: 0x0000000100003968 a.out`std::__1::__function::__alloc_func&lt;int (*)(int, int), std::__1::allocator&lt;int (*)(int, int)&gt;, int (int, int)&gt;::operator()[abi:se200000](this=0x000000016fdff280, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:171:12
    frame #4: 0x00000001000026bc a.out`std::__1::__function::__func&lt;int (*)(int, int), std::__1::allocator&lt;int (*)(int, int)&gt;, int (int, int)&gt;::operator()(this=0x000000016fdff278, __arg=0x000000016fdff224, __arg=0x000000016fdff220) at function.h:313:10
    frame #5: 0x0000000100003c38 a.out`std::__1::__function::__value_func&lt;int (int, int)&gt;::operator()[abi:se200000](this=0x000000016fdff278, __args=0x000000016fdff224, __args=0x000000016fdff220) const at function.h:430:12
    frame #6: 0x0000000100002038 a.out`std::__1::function&lt;int (int, int)&gt;::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
    frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
    frame #8: 0x0000000183cdf154 dyld`start + 2476
(lldb) 
```

after

```
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000100001f04 a.out`foo(x=1, y=1) at main.cpp:4:10
    frame #1: 0x0000000100003a00 a.out`decltype(std::declval&lt;int (*&amp;)(int, int)&gt;()(std::declval&lt;int&gt;(), std::declval&lt;int&gt;())) std::__1::__invoke[abi:se200000]&lt;int (*&amp;)(int, int), int, int&gt;(__f=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:149:25
    frame #2: 0x000000010000399c a.out`int std::__1::__invoke_void_return_wrapper&lt;int, false&gt;::__call[abi:se200000]&lt;int (*&amp;)(int, int), int, int&gt;(__args=0x000000016fdff280, __args=0x000000016fdff224, __args=0x000000016fdff220) at invoke.h:216:12
    frame #6: 0x0000000100002038 a.out`std::__1::function&lt;int (int, int)&gt;::operator()(this= Function = foo(int, int) , __arg=1, __arg=1) const at function.h:989:10
    frame #7: 0x0000000100001f64 a.out`main(argc=1, argv=0x000000016fdff4f8) at main.cpp:9:10
    frame #8: 0x0000000183cdf154 dyld`start + 2476
Note: Some frames were hidden by frame recognizers
```</pre>
</div>
</content>
</entry>
<entry>
<title>[lldb] [mostly NFC] Large WP foundation: WatchpointResources (#68845)</title>
<updated>2023-11-30T22:59:10+00:00</updated>
<author>
<name>Jason Molenda</name>
<email>jmolenda@apple.com</email>
</author>
<published>2023-11-27T21:28:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.belthelziquor.com/llvm-project.git/commit/?id=c73a3f16f81aaa427c61f69020a82b5b09570ffb'/>
<id>c73a3f16f81aaa427c61f69020a82b5b09570ffb</id>
<content type='text'>
This patch is rearranging code a bit to add WatchpointResources to
Process. A WatchpointResource is meant to represent a hardware
watchpoint register in the inferior process. It has an address, a size,
a type, and a list of Watchpoints that are using this
WatchpointResource.

This current patch doesn't add any of the features of
WatchpointResources that make them interesting -- a user asking to watch
a 24 byte object could watch this with three 8 byte WatchpointResources.
Or a Watchpoint on 1 byte at 0x1002 and a second watchpoint on 1 byte at
0x1003, these must both be served by a single WatchpointResource on that
doubleword at 0x1000 on a 64-bit target, if two hardware watchpoint
registers were used to track these separately, one of them may not be
hit. Or if you have one Watchpoint on a variable with a condition set,
and another Watchpoint on that same variable with a command defined or
different condition, or ignorecount, both of those Watchpoints need to
evaluate their criteria/commands when their WatchpointResource has been
hit.

There's a bit of code movement to rearrange things in the direction I'll
need for implementing this feature, so I want to start with reviewing &amp;
landing this mostly NFC patch and we can focus on the algorithmic
choices about how WatchpointResources are shared and handled as they're
triggeed, separately.

This patch also stops printing "Watchpoint &lt;n&gt; hit: old value: &lt;x&gt;, new
vlaue: &lt;y&gt;" for Read watchpoints. I could make an argument for print
"Watchpoint &lt;n&gt; hit: current value &lt;x&gt;" but the current output doesn't
make any sense, and the user can print the value if they are
particularly interested. Read watchpoints are used primarily to
understand what code is reading a variable.

This patch adds more fallbacks for how to print the objects being
watched if we have types, instead of assuming they are all integral
values, so a struct will print its elements. As large watchpoints are
added, we'll be doing a lot more of those.

To track the WatchpointSP in the WatchpointResources, I changed the
internal API which took a WatchpointSP and devolved it to a Watchpoint*,
which meant touching several different Process files. I removed the
watchpoint code in ProcessKDP which only reported that watchpoints
aren't supported, the base class does that already.

I haven't yet changed how we receive a watchpoint to identify the
WatchpointResource responsible for the trigger, and identify all
Watchpoints that are using this Resource to evaluate their conditions
etc. This is the same work that a BreakpointSite needs to do when it has
been tiggered, where multiple Breakpoints may be at the same address.

There is not yet any printing of the Resources that a Watchpoint is
implemented in terms of ("watchpoint list", or
SBWatchpoint::GetDescription).

"watchpoint set var" and "watchpoint set expression" take a size
argument which was previously 1, 2, 4, or 8 (an enum). I've changed this
to an unsigned int. Most hardware implementations can only watch 1, 2,
4, 8 byte ranges, but with Resources we'll allow a user to ask for
different sized watchpoints and set them in hardware-expressble terms
soon.

I've annotated areas where I know there is work still needed with
LWP_TODO that I'll be working on once this is landed.

I've tested this on aarch64 macOS, aarch64 Linux, and Intel macOS.

https://discourse.llvm.org/t/rfc-large-watchpoint-support-in-lldb/72116
(cherry picked from commit fc6b72523f3d73b921690a713e97a433c96066c6)
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch is rearranging code a bit to add WatchpointResources to
Process. A WatchpointResource is meant to represent a hardware
watchpoint register in the inferior process. It has an address, a size,
a type, and a list of Watchpoints that are using this
WatchpointResource.

This current patch doesn't add any of the features of
WatchpointResources that make them interesting -- a user asking to watch
a 24 byte object could watch this with three 8 byte WatchpointResources.
Or a Watchpoint on 1 byte at 0x1002 and a second watchpoint on 1 byte at
0x1003, these must both be served by a single WatchpointResource on that
doubleword at 0x1000 on a 64-bit target, if two hardware watchpoint
registers were used to track these separately, one of them may not be
hit. Or if you have one Watchpoint on a variable with a condition set,
and another Watchpoint on that same variable with a command defined or
different condition, or ignorecount, both of those Watchpoints need to
evaluate their criteria/commands when their WatchpointResource has been
hit.

There's a bit of code movement to rearrange things in the direction I'll
need for implementing this feature, so I want to start with reviewing &amp;
landing this mostly NFC patch and we can focus on the algorithmic
choices about how WatchpointResources are shared and handled as they're
triggeed, separately.

This patch also stops printing "Watchpoint &lt;n&gt; hit: old value: &lt;x&gt;, new
vlaue: &lt;y&gt;" for Read watchpoints. I could make an argument for print
"Watchpoint &lt;n&gt; hit: current value &lt;x&gt;" but the current output doesn't
make any sense, and the user can print the value if they are
particularly interested. Read watchpoints are used primarily to
understand what code is reading a variable.

This patch adds more fallbacks for how to print the objects being
watched if we have types, instead of assuming they are all integral
values, so a struct will print its elements. As large watchpoints are
added, we'll be doing a lot more of those.

To track the WatchpointSP in the WatchpointResources, I changed the
internal API which took a WatchpointSP and devolved it to a Watchpoint*,
which meant touching several different Process files. I removed the
watchpoint code in ProcessKDP which only reported that watchpoints
aren't supported, the base class does that already.

I haven't yet changed how we receive a watchpoint to identify the
WatchpointResource responsible for the trigger, and identify all
Watchpoints that are using this Resource to evaluate their conditions
etc. This is the same work that a BreakpointSite needs to do when it has
been tiggered, where multiple Breakpoints may be at the same address.

There is not yet any printing of the Resources that a Watchpoint is
implemented in terms of ("watchpoint list", or
SBWatchpoint::GetDescription).

"watchpoint set var" and "watchpoint set expression" take a size
argument which was previously 1, 2, 4, or 8 (an enum). I've changed this
to an unsigned int. Most hardware implementations can only watch 1, 2,
4, 8 byte ranges, but with Resources we'll allow a user to ask for
different sized watchpoints and set them in hardware-expressble terms
soon.

I've annotated areas where I know there is work still needed with
LWP_TODO that I'll be working on once this is landed.

I've tested this on aarch64 macOS, aarch64 Linux, and Intel macOS.

https://discourse.llvm.org/t/rfc-large-watchpoint-support-in-lldb/72116
(cherry picked from commit fc6b72523f3d73b921690a713e97a433c96066c6)
</pre>
</div>
</content>
</entry>
</feed>
