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2025-02-13[lldb] Change lldb's breakpoint handling behavior, reland (#126988)Jason Molenda
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
2024-07-19Revert "[lldb] Change lldb's breakpoint handling behavior (#96260)"Jason Molenda
This reverts commit 05f0e86cc895181b3d2210458c78938f83353002. The debuginfo dexter tests are failing, probably because the way stepping over breakpoints has changed with my patches. And there are two API tests fails on the ubuntu-arm (32-bit) bot. I'll need to investigate both of these, neither has an obvious failure reason.
2024-07-19[lldb] Change lldb's breakpoint handling behavior (#96260)Jason Molenda
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, but I'm convinced it 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 thread plan 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. I discussed this with Jim, and trying to paper over this behavior will lead to more complicated scenarios behaving non-intuitively. And mostly it's the testsuite that was trying to instruction step past a breakpoint and getting thrown off -- and I changed those tests to expect the new behavior. 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. rdar://123942164
2023-11-10[lldb] Change interface of StructuredData::Array::GetItemAtIndexAsDictionary ↵Alex Langford
(#71961) Similar to my previous patch (#71613) where I changed `GetItemAtIndexAsString`, this patch makes the same change to `GetItemAtIndexAsDictionary`. `GetItemAtIndexAsDictionary` now returns a std::optional that is either `std::nullopt` or is a valid pointer. Therefore, if the optional is populated, we consider the pointer to always be valid (i.e. no need to check pointer validity).
2023-10-25[lldb] Fix assertions caused by un-checked errors in ScriptedProcessMed Ismail Bennani
This patch should fix some assertion that started getting hit after f22d82c. That commit changed the scripted object plugin creation to use `llvm::Expected<T>` as a return type to enforce error handling, however I forgot to handle the error which caused the assert. The interesting part about this, is that since that assert was triggered in the ScriptedProcess constructor (where the `llvm::Error` wasn't handled), that impacted every test that launched any kind of process, since the process plugin manager would eventually also iterate over the `ScriptedProcess::Create` factory method. This patch should fix the assertions by handling the errors. Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
2023-10-25[lldb/Interpreter] Make ScriptedInterface Object creation more generic (#68052)Med Ismail Bennani
This patch changes the way plugin objects used with Scripted Interfaces are created. Instead of implementing a different SWIG method to create the object for every scripted interface, this patch makes the creation more generic by re-using some of the ScriptedPythonInterface templated Dispatch code. This patch also improves error handling of the object creation by returning an `llvm::Expected`. Signed-off-by: Med Ismail Bennani <ismail@bennani.ma> Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
2023-06-21[lldb] Fix failure in TestStackCoreScriptedProcess on x86_64Med Ismail Bennani
This patch should address the failure of TestStackCoreScriptedProcess that is happening specifically on x86_64. It turns out that in 1370a1cb5b97, I changed the way we extract integers from a `StructuredData::Dictionary` and in order to get a stop info from the scripted process, we call a method that returns a `SBStructuredData` containing the stop reason data. TestStackCoreScriptedProcess` was failing specifically on x86_64 because the stop info dictionary contains the signal number, that the `Scripted Thread` was trying to extract as a signed integer where it was actually parsed as an unsigned integer. That caused `GetValueForKeyAsInteger` to return the default value parameter, `LLDB_INVALID_SIGNAL_NUMBER`. This patch address the issue by extracting the signal number with the appropriate type and re-enables the test. Differential Revision: https://reviews.llvm.org/D152848 Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
2023-06-15[lldb] Introduce DynamicRegisterInfo::CreateFromDictAlex Langford
I want to add some error handling to DynamicRegisterInfo because there are many operations that can fail and many of these operations do not give meaningful information back to the caller. To begin that process, I want to add a static method that is responsible for creating a DynamicRegisterInfo from a StructuredData::Dictionary (and ArchSpec). This is meant to replace the equivalent constructor because constructors are ill-equipped to perform error handling. Differential Revision: https://reviews.llvm.org/D152594
2023-06-13Revert "[lldb] Fix failure in TestStackCoreScriptedProcess on x86_64"Med Ismail Bennani
This reverts commit 4177b490358432a457935ba5d6d076ae60de588f, since I landed it by mistake.
2023-06-13[lldb] Fix failure in TestStackCoreScriptedProcess on x86_64Med Ismail Bennani
This patch should address the failure of TestStackCoreScriptedProcess that is happening specifically on x86_64. It turns out that in 1370a1cb5b97, I changed the way we extract integers from a `StructuredData::Dictionary` and in order to get a stop info from the scripted process, we call a method that returns a `SBStructuredData` containing the stop reason data. TestStackCoreScriptedProcess` was failing specifically on x86_64 because the stop info dictionary contains the signal number, that the `Scripted Thread` was trying to extract as a signed integer where it was actually parsed as an unsigned integer. That caused `GetValueForKeyAsInteger` to return the default value parameter, `LLDB_INVALID_SIGNAL_NUMBER`. This patch address the issue by extracting the signal number with the appropriate type and re-enables the test. Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
2023-05-22[lldb] Add "Trace" stop reason in Scripted ThreadMed Ismail Bennani
This patch adds support to eStopReasonTrace to Scripted Threads. This is necessary when using a Scrited Process with a Scripted Thread Plan to report a special thread stop reason to the thread plan. rdar://109425542 Differential Revision: https://reviews.llvm.org/D151043 Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
2023-05-22[lldb] Add support for negative integer to {SB,}StructuredDataMed Ismail Bennani
This patch refactors the `StructuredData::Integer` class to make it templated, makes it private and adds 2 public specialization for both `int64_t` & `uint64_t` with a public type aliases, respectively `SignedInteger` & `UnsignedInteger`. It adds new getter for signed and unsigned interger values to the `StructuredData::Object` base class and changes the implementation of `StructuredData::Array::GetItemAtIndexAsInteger` and `StructuredData::Dictionary::GetValueForKeyAsInteger` to support signed and unsigned integers. This patch also adds 2 new `Get{Signed,Unsigned}IntegerValue` to the `SBStructuredData` class and marks `GetIntegerValue` as deprecated. Finally, this patch audits all the caller of `StructuredData::Integer` or `StructuredData::GetIntegerValue` to use the proper type as well the various tests that uses `SBStructuredData.GetIntegerValue`. rdar://105575764 Differential Revision: https://reviews.llvm.org/D150485 Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>
2023-02-06[lldb/Plugins] Fix method dispatch bug when using multiple scripted processesMed Ismail Bennani
This patch should address a bug when a user have multiple scripted processes in the same debugging session. In order for the scripted process plugin to be able to call into the scripted object instance methods to fetch the necessary data to reconstruct its state, the scripted process plugin calls into a scripted process interface, that has a reference to the created script object instance. However, prior to this patch, we only had a single instance of the scripted process interface, living the script interpreter. So every time a new scripted process plugin was created, it would overwrite the script object instance that was held by the single scripted process interface in the script interpreter. That would cause all the method calls made to the scripted process interface to be dispatched by the last instanciated script object instance, which is wrong. In order to prevent that, this patch moves the scripted process interface reference to be help by the scripted process plugin itself. rdar://104882562 Differential Revision: https://reviews.llvm.org/D143308 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2023-01-12[lldb/Interpreter] Make ScriptedProcessInfo more genericMed Ismail Bennani
This patch moves the ScriptedProcessInfo class out of the ScriptedProcess and hoist it as a standalone interpreter class, so it can be reused with the Scripted Platform. Differential Revision: https://reviews.llvm.org/D139247 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2023-01-07[lldb] Use std::optional instead of llvm::Optional (NFC)Kazu Hirata
This patch replaces (llvm::|)Optional< with std::optional<. I'll post a separate patch to clean up the "using" declarations, #include "llvm/ADT/Optional.h", etc. This is part of an effort to migrate from llvm::Optional to std::optional: https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2023-01-07[lldb] Add #include <optional> (NFC)Kazu Hirata
This patch adds #include <optional> to those files containing llvm::Optional<...> or Optional<...>. I'll post a separate patch to actually replace llvm::Optional with std::optional. This is part of an effort to migrate from llvm::Optional to std::optional: https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-11-03[lldb/crashlog] Add support for Application Specific Backtraces & InformationMed Ismail Bennani
For an exception crashlog, the thread backtraces aren't usually very helpful and instead, developpers look at the "Application Specific Backtrace" that was generated by `objc_exception_throw`. LLDB could already parse and symbolicate these Application Specific Backtraces for regular textual-based crashlog, so this patch adds support to parse them in JSON crashlogs, and materialize them a HistoryThread extending the crashed ScriptedThread. This patch also includes the Application Specific Information messages as part of the process extended crash information log. To do so, the ScriptedProcess Python interface has a new GetMetadata method that returns an arbitrary dictionary with data related to the process. rdar://93207586 Differential Revision: https://reviews.llvm.org/D126260 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2022-11-03[lldb/Plugins] Cleanup error handling in Scripted{Process,Thread} (NFC)Med Ismail Bennani
Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2022-09-13[lldb] Fixed a number of typosGabriel Ravier
I went over the output of the following mess of a command: (ulimit -m 2000000; ulimit -v 2000000; git ls-files -z | parallel --xargs -0 cat | aspell list --mode=none --ignore-case | grep -E '^[A-Za-z][a-z]*$' | sort | uniq -c | sort -n | grep -vE '.{25}' | aspell pipe -W3 | grep : | cut -d' ' -f2 | less) and proceeded to spend a few days looking at it to find probable typos and fixed a few hundred of them in all of the llvm project (note, the ones I found are not anywhere near all of them, but it seems like a good start). Differential revision: https://reviews.llvm.org/D131122
2022-08-11[lldb/crashlog] Improve exception reporting for interactive modeMed Ismail Bennani
This patch improve exception reporting when loading a crash report in a scripted process. Now, we parse the `exception` dictionary from the crash report use it the create a higher fidelity `MachException` stop info. This patch also updates the test to reflect that change. rdar://97096486 Differential Revision: https://reviews.llvm.org/D131086 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2022-03-04[lldb/Plugin] Use static ScriptedInterface::ErrorWithMessage function (NFC)Med Ismail Bennani
This patch replaces the calls to ErrorWithMessage using the GetInterface message by a call to the static method directly. Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2022-02-16[lldb/Plugin] Add artificial stackframe loading in ScriptedThreadMed Ismail Bennani
This patch adds the ability for ScriptedThread to load artificial stack frames. To do so, the interpreter instance can create a list that will contain the frame index and its pc address. Then, when the Scripted Process plugin stops, it will refresh its Scripted Threads state by invalidating their register context and load to list from the interpreter object and reconstruct each frame. This patch also removes all of the default implementation for `get_stackframes` from the derived ScriptedThread classes, and add the interface code for the Scripted Thread Interface. rdar://88721095 Differential Revision: https://reviews.llvm.org/D119388 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2022-02-03[lldb] Rename Logging.h to LLDBLog.h and clean up includesPavel Labath
Most of our code was including Log.h even though that is not where the "lldb" log channel is defined (Log.h defines the generic logging infrastructure). This worked because Log.h included Logging.h, even though it should. After the recent refactor, it became impossible the two files include each other in this direction (the opposite inclusion is needed), so this patch removes the workaround that was put in place and cleans up all files to include the right thing. It also renames the file to LLDBLog to better reflect its purpose.
2022-02-02[lldb] Convert "LLDB" log channel to the new APIPavel Labath
2022-01-24[lldb/Plugins] Fix ScriptedThread IndexID reportingMed Ismail Bennani
When listing all the Scripted Threads of a ScriptedProcess, we can see that all have the thread index set to 1. This is caused by the lldb_private::Thread constructor, which sets the m_index_id member using the provided thread id `tid`. Because the call to the super constructor is done before instantiating the `ScriptedThreadInterface`, lldb can't fetch the thread id from the script instance, so it uses `LLDB_INVALID_THREAD_ID` instead. To mitigate this, this patch takes advantage of the `ScriptedThread::Create` fallible constructor idiom to defer calling the `ScriptedThread` constructor (and the `Thread` super constructor with it), until we can fetch a valid thread id `tid` from the `ScriptedThreadInterface`. rdar://87432065 Differential Revision: https://reviews.llvm.org/D117076 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2022-01-24[lldb/Plugins] Enrich ScriptedThreads Stop Reasons with ExceptionsMed Ismail Bennani
This patch adds Exceptions to the list of supported stop reasons for Scripted Threads. The main motivation for this is that breakpoints are triggered as a special exception class on ARM platforms, so adding it as a stop reason allows the ScriptedProcess to selected the ScriptedThread that stopped at a breakpoint (or crashed :p). rdar://87430376 Differential Revision: https://reviews.llvm.org/D117074 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2022-01-24[lldb/Plugins] Add support of multiple ScriptedThreads in a ScriptedProcessMed Ismail Bennani
This patch adds support of multiple Scripted Threads in a ScriptedProcess. This is done by fetching the Scripted Threads info dictionary at every ScriptedProcess::DoUpdateThreadList and iterate over each element to create a new ScriptedThread using the object instance, if it was not already available. This patch also adds the ability to pass a pointer of a script interpreter object instance to initialize a ScriptedInterface instead of having to call the script object initializer in the ScriptedInterface constructor. This is used to instantiate the ScriptedThreadInterface from the ScriptedThread constructor, to be able to perform call on that script interpreter object instance. Finally, the patch also updates the scripted process test to check for multiple threads. rdar://84507704 Differential Revision: https://reviews.llvm.org/D117071 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2022-01-24[lldb/Plugins] Move ScriptedThreadInterface to ScriptedThreadMed Ismail Bennani
Since we can have multiple Scripted Threads per Scripted Process, having only a single ScriptedThreadInterface (with a single object instance) will cause the method calls to be done on the wrong object. Instead, this patch creates a separate ScriptedThreadInterface for each new lldb_private::ScriptedThread to make sure we interact with the right instance. rdar://87427911 Differential Revision: https://reviews.llvm.org/D117070 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-12-06[lldb/plugins] Add arm64(e) support to ScriptedProcessMed Ismail Bennani
This patch adds support for arm64(e) targets to ScriptedProcess, by providing the `DynamicRegisterInfo` to the base `lldb.ScriptedThread` class. This allows create and debugging ScriptedProcess on Apple Silicon hardware as well as Apple mobile devices. It also replace the C++ asserts on `ScriptedThread::GetDynamicRegisterInfo` by some error logging, re-enables `TestScriptedProcess` for arm64 Darwin platforms and adds a new invalid Scripted Thread test. rdar://85892451 Differential Revision: https://reviews.llvm.org/D114923 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-11-11[lldb/Plugins] Refactor ScriptedThread register context creationMed Ismail Bennani
This patch changes the ScriptedThread class to create the register context when Process::RefreshStateAfterStop is called rather than doing it in the thread constructor. This is required to update the thread state for execution control. Differential Revision: https://reviews.llvm.org/D112167 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-11-10[lldb] Fix Scripted ProcessLaunchInfo Argument nullptr derefMed Ismail Bennani
This patch adds a new `StructuredData::Dictionary` constructor that takes a `StructuredData::ObjectSP` as an argument. This is used to pass the opaque_ptr from the `SBStructuredData` used to initialize a ScriptedProecss, to the `ProcessLaunchInfo` class. This also updates `SBLaunchInfo::SetScriptedProcessDictionary` to reflect the formentionned changes which solves the nullptr deref. Differential Revision: https://reviews.llvm.org/D112107 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-10-08[lldb/Plugins] Replace platform-specific macro with LLVM_PRETTY_FUNCTION (NFC)Med Ismail Bennani
This patch refactors Scripted Process and Scripted Thread related classes to use LLVM_PRETTY_FUNCTION instead of the compiler macro. Differential Revision: https://reviews.llvm.org/D111452 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2021-10-08[lldb/Plugins] Add support for ScriptedThread in ScriptedProcessMed Ismail Bennani
This patch introduces the `ScriptedThread` class with its python interface. When used with `ScriptedProcess`, `ScriptedThreaad` can provide various information such as the thread state, stop reason or even its register context. This can be used to reconstruct the program stack frames using lldb's unwinder. rdar://74503836 Differential Revision: https://reviews.llvm.org/D107585 Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>